[Double ovulation in mares. Clinical, hormone analytical and sonographic studies]. 108 mares with a total of 135 oestrous cycles were examined. 30% of the mares showed development of double follicles, found by palpation and ultrasonography. Eight cases of double ovulation, four of them synchronous and four asynchronous, were examined closely. These cases of double ovulation showed different growth and different development of the follicular wall. This occurred at the same time in cases of synchronous double ovulation whereas it differed in case of asynchronous double ovulation. The later ovulating follicle was still growing while the first one had already burst. With both forms of double ovulation an equal concentration of progesterone was detected in peripheral blood. On the day of ovulation the rate of progesterone was low (1 ng/ml blood plasma) and it first started rising from the day +1 on. Double follicles matured slower than single follicles. Mares with synchronous double ovulation showed the typical oestrus behavior. This behavior was less distinct after the first ovulation in mares with asynchronous double ovulation. All four mares with asynchronous and two mares with synchronous double ovulation became pregnant. Twins did not occur. A possible relationship between double ovulation and twin pregnancy is discussed.


[Pathology of the cornea].

[Pathology of the cornea]. The basic pathologic mechanisms of corneal inflammation, including hereditary and degenerative-dystrophic keratopathies, are presented. Inflammatory keratopathies of non-ulcerative and ulcerative forms, which often occur in the ophthalmopathological diagnostics, are described, and special nosological entities are emphasized. The consequences of corneal ulceration are mentioned, and the incidence of neoplastic corneal processes is considered.


[Cytology of the cerebrospinal fluid in dogs with brain tumors and spinal cord compression. Part 4]. The results of cerebrospinal fluid (CSF) cytology of 9 dogs with brain tumors and 50 dogs with spinal cord compression are discussed. Of the 50 dogs with spinal cord compression, disc protrusion was diagnosed in 31, myelomalacia in 7, discospondylitis in 3 and spinal cord tumors in 9 dogs. In 4 of 9 dogs with brain tumors, tumor cells could be found by the sedimentation apparatus of Kölmel. Pleocytosis existed in 6 patients. In about 70% (29 of 41) of cases with disc protrusion, more than 200 cells could be evaluated in the CSF sediment, consisting mostly of transformed lymphocytes and activated monocytes. As the neurologic deficits increased, the amount of cells and especially cell complexes increased. This was especially evident in cases with myelomalacia of the spinal cord. Only in cases with discospondylitis or spinal cord neoplasia was the CSF cytology unchanged.


[The blood supply to the stomach of the dog--a corrosion cast and scanning electron microscopic study]. An unimpaired vascular circulation is vital for gastric function. The arteries of the stomach originate from the coeliac artery; the veins lead to the portal vein. Arteries in the right half of the organ form a perigastric circle of anastomosing vessels, which is lacking on the left side. The basal capillary network of the gastric submucosa shows no important regional differences. Territories of vascularisation are documented for the canine stomach.


Calcium antagonists and the kidney.

Calcium antagonists and the kidney. Recently, attention has focused on the effects of calcium antagonists on renal function. When administered in vitro to the isolated perfused kidney, calcium antagonist exhibit consistent actions permitting characterization of their renal effects. Calcium antagonists do not affect the vasodilated isolated perfused kidney, but they do dramatically alter the response of the kidney to vasoconstrictor agents. In the presence of norepinephrine, calcium antagonists markedly augment glomerular filtration rate but produce only a modest improvement in renal perfusion. Utilizing the isolated perfused hydronephrotic rat kidney model that permits direct visualization of afferent and efferent arterioles, we have demonstrated that this preferential augmentation of glomerular filtration rate is primarily attributable to a selective vasodilation of pre-glomerular vessels. Although the clinical implications of such observations are not yet clear, preliminary studies in experimental animal models indicate that calcium antagonists may exert salutary effects on renal function in clinical settings that are characterized by impaired renal hemodynamics. The possible benefits of calcium antagonists in ameliorating the development of renal dysfunction in patients in whom there is increased risk for the development of acute renal insufficiency remain to be evaluated.


The diuretic effect of calcium entry blockade in normals and hypertensive patients. Calcium entry blockers have been shown to exert hemodynamic and diuretic effects in the kidney. The diuretic effects can be demonstrated most clearly in the isolated perfused kidney, not influenced by compensatory mechanisms such as a lower blood pressure or changes of hormones. However, they can also be shown in vivo in humans. We studied the renal effects of calcium entry blockade after the first dosage and after continued oral dosages of 20 mg nicardipine tid in patients with essential hypertension and in normotensive controls. Renal function was determined during maximal free water clearance, allowing estimation of changes in "proximal" and "distal" tubular sodium reabsorption. Results showed a natriuretic effect. In the control subjects, clearance results were compatible with a decrease of proximal and distal tubular reabsorption, but in the hypertensive group natriuresis was mainly achieved by an increase of the glomerular filtration rate and a decrease of fractional distal reabsorption. In both groups the natriuresis occurred concomitantly with a lower blood pressure. The ratio plasma renin activity/plasma aldosterone concentration increased, although nicardipine did not inhibit the increase of plasma aldosterone during angiotensin II infusion. Pre-treatment with the calcium entry blocker nitrendipine enhanced the natriuretic effect of atrial natriuretic factor (ANF) in sodium replete normal volunteers. Facilitation of sodium excretion by human ANF may be an additional diuretic mechanism of calcium entry blockers.


Systemic and renovascular hypertension.

Systemic and renovascular hypertension. To ascertain the contribution of systemic hypertension in the progression of renal failure, we have studied the effects of pharmacological treatment of hypertension in rats with the remnant kidney model of renal insufficiency, streptozotocin diabetes, or nephrotoxic serum nephritis. Treatment with the angiotensin converting enzyme (ACE) inhibitor enalapril lowered systemic blood pressure in the remnant kidney and diabetic animals, but did not lower blood pressure in rats with nephrotoxic serum nephritis. Proteinuria was reduced in all three models, and creatinine clearance improved in the remnant kidney and diabetic animals, when compared with untreated controls. In the remnant kidney and diabetic models systemic blood pressure was lowered to a similar degree by treatments with a calcium blocker, with no improvement in either proteinuria, or glomerular filtration rate. Further studies of the long-term effects of enalapril have been undertaken in rats with the two kidney one clip model of hypertension. Rats treated with enalapril had a lower blood pressure and improved survival over one year of treatment, compared with untreated rats. After 1 year of treatment however the clipped kidney was small and fibrotic, and non functional. Following withdrawal of enalapril therapy there was no functional improvement of the clipped kidney. The possibility that ACE inhibitors have a specific intra-renal effect reducing the rate of progression of renal disease now needs confirmation in human studies. In renovascular hypertension however, intra-renal changes induced by ACE inhibitors may cause irreversible renal damage.


Preservation of renal function in chronic renal failure. Mechanisms of progression of chronic renal failure (CRF) have been well documented in the rat but may not be relevant in man. Factors which may modify clinical CRF include underlying disease, diet, hypertension, intercurrent events, and adverse or beneficial effects of drug therapy. It has been argued that progression in many forms of renal disease is inexorable below a certain level of renal function. In other diseases, eg primary malignant hypertension, analgesic nephropathy, function frequently improves in both the short and long term with appropriate management. Thus knowledge of the nature of the underlying disease is essential in assessing progression. The value of diet in preserving renal function has been debated, particularly the relative roles of protein and phosphate control. In our own unit, a prospective randomized study showed a benefit of protein restriction. Development of accelerated hypertension is an important cause of progression of renal disease and clinical and experimental evidence supports the view that non-accelerated hypertension is also a factor in progression, amenable to treatment. Various intercurrent events may accelerate progression and function may be lost permanently following sepsis, urinary tract obstruction, renal arterial or venous obstruction, hypotension and in some cases pregnancy. Numerous drugs can have deleterious effects on the kidney. The possibility that converting enzyme inhibitors might preserve renal function is attracting attention but in view of their side effects their place in therapy should be determined by prospective controlled studies in which the above factors are carefully considered.


Localization of components of the renin-angiotensin system within the kidney and sustained release of angiotensins from isolated and perfused kidney. We found colocalization of renin, angiotensin (Ang) I and Ang II in juxtaglomerular (JG) cells of the kidney. Coexistence of Ang II in renin granules was demonstrated by electron microscopic immunogold labeling of these components. Coexistence of both Ang I and Ang II in the high density renin storage granules were also demonstrated by gradient centrifugation of renal homogenate. These findings supported the synthesis of Ang I and Ang II in juxtaglomerular cells. Isolated and cultured JG cells showed the synthesis of Ang I, Ang II and renin. Ang I and Ang II were secreted from isolated and perfused rat kidneys at steady rates over 2 hr. Their secretion rates were proportional to that of renin. The rate of Ang II secretion from the kidney was higher than that from the vascular bed. Ang II was also found in renal lymph. These findings indicate that a large amount of Ang II is generated in JG cells by the intracellular action of renin and may play a significant role in the regulation of renal function.


Effect of sulindac on prostaglandin synthesis in human and in cultured rat renal and vascular smooth muscle cells. To examine the hypothesis that sulindac does not inhibit renal prostaglandin (PG) synthesis, we investigated the effects of sulindac and other nonsteroidal anti-inflammatory drugs on PG synthesis in human and in cultured rat renal and vascular smooth muscle (VSM) cells. In 7 patients with chronic glomerular disease, creatinine clearance and proteinuria were not changed by sulindac but were significantly reduced by diclofenac sodium. However, urinary excretion of PGE2 was decreased by both drugs. In cultured glomerular mesangial (GM), renal papillary collecting tubule (RPCT) and VSM cells from mesenteric artery, indomethacin, tiaprofenic acid, aspirin and ibuprofen inhibited both basal and arachidonic acid (AA)-stimulated PG synthesis dose-dependently. Although sulindac sulfoxide, at the same concentrations, inhibited both basal and AA-stimulated PGE2 synthesis in RPCT cells, it was less potent to inhibit PGI2 synthesis in VSM cells or PGE2 synthesis in GM cells. Active form sulindac sulfide inhibited PG synthesis in all types of cells but its inactive form sulfone did not. We conclude that sulindac inhibits renal PG synthesis but has little effect on renal function. This may be explained by its relatively weak potency on glomerular or vascular PG synthesis inhibition possibly due to the different biotransformation of the sulfoxide to the active sulfide in these cells.


Macula densa control of renin release and glomerular hemodynamics. In each nephron of the mammalian kidney, the tubule returns to the hilus of the parent glomerulus, forming the juxtaglomerular apparatus (JGA). The JGA displays a unique arrangement of afferent and efferent arterioles, interstitial cells and macula densa (a specialized plaque of tubular epithelial cells). Because of this intimate anatomical relationship, it has long been suggested that the macula densa may somehow sense changes in the composition of the tubular fluid and control both the glomerular filtration rate and renin release. Despite extensive investigation, attempts to obtain direct evidence of this have been hindered by the anatomical complexity of the JGA. However, recent technical developments now permit direct assessment of the role of the macula densa in the control of both renin release and glomerular hemodynamics. These developments include microdissection/perfusion of the afferent arteriole, the macula densa or both, as well as a sensitive renin assay which permits measurement of renin release from a single JGA. Observations resulting from such developments are discussed in this article.


Localization and regulation of renal receptors for angiotensin II and atrial natriuretic peptide. The anatomical distribution of receptors for angiotensin II (Ang II) and atrial natriuretic peptide (ANP) within the kidney has been investigated by in vitro autoradiography. Ang II and ANP receptor binding occurs together in several sites in the kidney, including renal vasculature, glomeruli, proximal convoluted tubule of the outer cortex, and the vasa recta bundles of the inner stripe of the outer medulla. However, in the glomeruli, Ang II receptor binding occurs predominantly in mesangial cells, while ANP receptors are localized mainly to the visceral epithelial cells. In the inner medulla, there is a moderate density of ANP receptors in marked contrast with Ang II binding which is not detected in this site. Both Ang II and ANP receptors are modulated by alterations in sodium and fluid intake, and the peptides themselves. The overlapping distribution of receptors for these two peptide hormones in several intrarenal sites may provide an anatomical basis for their physiological interaction to regulate renal hemodynamics and tubular reabsorption of sodium and water.


Eicosanoids, mesangial contraction, and intracellular signal transduction. The glomerular mesangial cell is a specialized pericyte with multiple functional capabilities including contraction. Mesangial contraction may reduce the glomerular filtration surface area and hence the ultrafiltration coefficient, Kf. Cultured mesangial cells convert arachidonic acid into biologically active eicosanoids which are either contractile (thromboxane A2 [TxA2], prostaglandin F2 alpha [PGE2 alpha]) or relaxant (PGE2, PGI2). The addition of TxA2 analogues, PGE2 or sulfidopeptide leukotrienes (LTC4 and LTD4) stimulated contraction of cultured mesangial cells with threshold responses at approximately 1 nM and maximum responses at 1 microM. PGE2 and PGI2 antagonized mesangial contraction induced by TxA2 analogues. Contraction was enhanced by inhibiting mesangial cyclooxygenase with nonsteroidal antiinflammatory drugs (NSAID). Contractile eicosanoids stimulated phospholipase C thereby elevating intracellular inositol trisphosphate and cytosolic free Ca2+ concentration ([Ca2+]i). Vasorelaxant prostanoids stimulated adenylate cyclase, increasing intracellular cyclic AMP. We conclude that eicosanoids control mesangial contractility by regulating [Ca2+]i and cAMP. NSAID increase mesangial reactivity by blocking the inhibitory effects of endogenous vasodilator eicosanoids, with potential consequences on glomerular hemodynamics.


Functions of ascending thin limb of Henle's loop with special emphasis on mechanism of NaCl transport. Major controversy concerning the ascending thin limb of Henle's loop (ATL) centers on the urine concentration mechanism based on the countercurrent multiplier system in the inner medulla of the kidney. This renal tubular segment has specific transport properties which function to dilute the urine without any movement of water across the epithelium. This segment is fundamentally impermeable to water, moderately permeable to urea, and highly permeable to Na+ and Cl-. Whether NaCl is reabsorbed actively in the ATL has long been an important question. While mathematical modelling studies have failed to explain completely how the osmotic gradient in the inner medulla is generated without active NaCl transport in the ATL, the experimental data support the view that active NaCl reabsorption is absent. Recently, we succeeded in measuring the intracellular Na+ concentration by using the fluorescent Na+ indicator sodium-binding benzofuran isophthalate in the in vitro microperfused ATL. Our data suggest that the ATL maintains a low intracellular Na+ concentration by the ouabain-sensitive Na+/K+ ATPase in the basolateral membrane, and that the luminal membrane of the ATL has furosemide-insensitive Na+ permeability. Active Na+ reabsorption estimated in our study amounts to only a few per cents of the net Na+ reabsorption in the ATL. It is therefore suggested that the major role of Na+ extrusion in the ATL cells is to maintain a low cellular Na+ concentration against ambient hyperosmolarity, although small but substantial amount of Na+ is reabsorbed by the furosemide-insensitive Na+ permeability and ouabain-sensitive Na+/K+ ATPase.


Effect of acute and chronic treatment of tin on blood pressure in spontaneously hypertensive rats. Cytochrome P450-dependent metabolites of arachidonic acid (AA) are increased in the kidneys of spontaneously hypertensive rats (SHR) as compared to control rats (WKY) in the period of rapid elevation of blood pressure (BP) from 5 to 13 weeks. We treated rats with stannous chloride (SnCl2) (10 mg/100 g body weight/day for 4 days) to decrease selectively renal cytochrome P450 content through increasing renal heme oxygenase activity. A decrease in renal cytochrome P450-dependent AA metabolites was associated with decreased BP and increased urinary Na+ excretion in 7- but not in 20-week-old SHR rats. Chronic treatment with SnCl2 (10 mg/100 g body weight twice a week) from 5 to 20 weeks prevented the elevation of BP in SHR rats. Further, the antihypertensive effects of tin persisted for 7 weeks beyond its discontinuation. BP in WKY rats was unaffected by tin. Both the acute and chronic treatment with tin are the first studies to demonstrate amelioration of hypertension in SHR by an intervention which is targeted at a single enzyme system.


Roles of renal cytochrome P450-dependent arachidonic acid metabolites in hypertension. Cytochrome P450 represents the third metabolic pathway of arachidonic acid giving rise to several biologically active compounds, such as 19-HETE, 20-HETE and EETs and their corresponding DHETs. The kidney is the rich source of these metabolites which have some important biologic actions within the kidney. These metabolites have a wide and contrasting spectrum of biological and renal effects, from vasodilation to vasoconstriction and from inhibition to stimulation of Na-K-ATPase, their relative production rates may influence not only renal hemodynamics but also pro- and anti-hypertensive mechanisms of hypertension. There is increasing evidence that the abnormality of these metabolites in animal models of hypertension. However, sufficient evidence of the physiological and pathophysiological roles of hypertension in man is still lacking.


Experimental studies on carcinogenesis in anomalous arrangement of the pancreaticobiliary ducts. An experimental model of anomalous arrangement of the pancreaticobiliary ducts (APBD) was produced by pancreaticocholecystostomy performed in 29 mongrel dogs. Our purpose was to study carcinogenesis of the extrahepatic biliary tract by DNA ploidy analysis with cytofluorometry. The amylase level in the bile was elevated in all 25 dogs tested except the controls. The phospholipase A2 level in the bile was elevated in all selected dogs except the controls. Common bile duct (CBD) dilatation was found in 23/29 (79%) of the dogs, and biliary stones were found in 3/29 (10%) dogs. Inflammatory changes were observed microscopically in all specimens except those from the controls. Intramural glandular structures were found in 17/25 (68%) of gallbladder (GB) specimens and 10/25 (40%) of CBD specimens; goblet cells were found in 7/25 (28%) of GB specimens and 2/25 (8%) of CBD specimens. In the controls neither glandular structures nor goblet cells were observed except for two GB specimens showing mild cholecystitis. Cytofluorometry showed 21% GB and 7% CBD diploidy, 69% GB and 65% CBD low ploidy, 10% GB and 28% CBD high ploidy patterns of histograms. These results show that, APBD may be central to high risk condition or play a key role to develop atypical biliary tract epithelium and DNA ploidy abnormality with or without biliary duct dilatation.


Correlation of carotid B-mode scanning with endarterectomy findings in Japanese patients. In this study, 13 Japanese patients who underwent carotid endarterectomy with en bloc method were prospectively evaluated by high-resolution B-mode scanning. B-mode imaging was carried out 1-2 days before operation. The most suitable consecutive longitudinal planes of the carotid bifurcation were photographed (5-8 planes). The echogain was gradually changed from a lower to a higher intensity during B-mode scanning to identify the echogenicity of the atheromatous plaques. Three-dimensional reconstructions were made of the carotid plaques before performing carotid endarterectomy, and the author investigated the correlations between the echo characteristics and the histology of the resected plaques. The echogenicity of all atheromatous plaques, except for those with calcification, was lower than that of the normal medial layer of the vessel wall. The consecutive B-mode image data correlated well with the histological findings of the resected plaques in this study. In 2 out of 13 cases, it was found to be very difficult to distinguish an ulcerated plaque from a region of fresh intraplaque hemorrhage. High-resolution B-mode scanning was found to be a very useful and reliable method for identifying the detailed structure of atheromatous plaques in the cervical carotid artery.


Clinical appraisal of stereotactic hematoma aspiration surgery for hypertensive thalamic hemorrhage--with respect to volume of the hematoma. Three hundred and four patients with hypertensive thalamic hemorrhage were managed by medical treatment, ventricular drainage, or CT-controlled stereotactic aspiration surgery (AS). The therapeutic results of the 6-month outcome were analyzed and correlated with the volume of the hematoma. A hematoma volume of 20 ml was thought to be the critical size in determining whether the outcome would be favourable or unfavorable. Indications for AS are suggested as follows. In patients with a small-sized hematoma having a volume of less than 10 ml use of AS should be restricted to patients with severe paralysis or other neurological complications and the elderly (aged 70 years or older). For patients with a medium-sized hematoma having a volume between 10 ml and 20 ml, AS is indicated for patients having severe paralysis and disturbances of consciousness. For patients with a large-sized hematoma having a volume of 20 ml or more, AS increases not only the survival rate of patients but also reduces the number of bedridden patients. We conclude that AS opens up a new avenue of surgical treatment for hypertensive thalamic hemorrhage, which has been no indication for hematoma evacuation by conventional craniotomy.


Accuracy of the results measured by in vivo 1H-MRS using model solutions. In in vivo 1H-MRS of human brain, main three metabolites such as N-acetyl-L-aspartate (NAA), creatine/phosphocreatine (PCr/Cr), and choline (Cho) have been observed. In this paper an accuracy of the results measured by in vivo 1H-MRS using above model solutions was discussed. 1.0 mmol/l choline and 1.5 mmol/l creatine/phosphocreatine saline solutions were measured with STEAM method (echo time 270 msec). The peak area of Cho was larger than that of PCr/Cr against their concentrations and was linearly increased with its concentration in the range of 5.8 and 29 mumol/27 cm3. Although both peak areas of Cho and Cr/PCr were varied with Volume-of-interest (VOI) coordinates, the ratio of Cho to PCr/Cr was approximately 1.6.


Glutamine antagonist with diet deficient in glutamine and aspartate reduce tumor growth. This study was designed to investigate whether a combination of a glutamine antagonist (DON) and a diet deficient in glutamate and aspartate (AG) altered glutamine metabolism in tumor tissue, and inhibited tumor growth. In experiment-1, 21 male Donryu rats were fed with AG and implanted with Yoshida's Sarcoma. Of them, 7 rats were sacrificed on the 5th day (group AG), other 7 were sacrificed next day (group AG-1) and the remaining 7 were injected with DON on the 5th day and sacrificed next day (group AG+D). The tumor weight of group AG+D was significantly lower than of group AG, or of group AG-1. In experiment-2, of 23 rats, 9 were fed with control diet and 14 were fed with AG and implanted. 12 were sacrificed on the 5th day (group C, AG), and 11 were injected with DON on the 5th day and sacrificed next day (group C+D, AG+D). The reduced ratio of tumor weight in group C+D and group AG+D were 25% and 67%, respectively. These results show that the tumor growth could be inhibited by using metabolic antagonist of glutamine, and that it had synergistic effect in conjunction with the imbalanced diet.


Comparison of cytofluorometric nuclear DNA ploidy analysis on fresh and paraffin embedded specimen. The cytofluorometric nuclear DNA ploidy analysis was performed in gallbladder (GB) epithelium of eight patients of chronic cholecystitis to make a comparison between fresh and paraffin embedded tissue analysis, to make an ideal single cellular suspension, to evaluate the ploidy pattern affected by inflammation and to assess the histological correlations. Six (75%) fresh specimens and eight (100%) paraffin embedded specimens showed diploidy pattern of histogram. Two (25%) fresh specimens showed low ploidy pattern of histogram. There was a good correlation between histological findings and the ploidy patterns of 100% paraffin embedded specimens and 75% fresh specimens. The relative fluorescence intensity was found higher and more stable in paraffin embedded tissues than fresh tissues. Inflammation did not affect the ploidy patterns of paraffin embedded specimens whereas the ploidy patterns of fresh specimens were affected. It can be concluded that the DNA ploidy patterns and histological findings have a good correlation and inflammation does not affect the cytofluorometric DNA ploidy pattern when using the paraffin embedded specimens. Paraffin embedded specimens are superior to fresh specimens for making an ideal single cellular suspension to obtain stable, high, and accurate fluorescence intensity with less background fluorescence which makes the ploidy pattern behave like exact behavior of tissues.


Quantified application of MRI for diagnosis of head and neck tumors. We evaluated T/M ratios and T2 values of 6 malignant lymphomas and 8 squamous cell carcinomas in the head and neck in order to differentiate these two entities. T/M ratios were calculated by dividing intensity of tumor by that of muscle in same slice images. T2 values were calculated from T2-weighted images and proton-weighted images. Statistical difference of T/M ratios was found between malignant lymphomas and squamous cell carcinomas, but no difference of T2 values was seen between two groups. T/M ratio was considered to be a useful and quantified index for evaluation of head and neck tumor.


Intramedullary spinal cord metastasis from lung cancer presenting with paraparesis: an autopsied case. A 75-year-old male presented with paraparesis and pain in the thighs, which progressed rapidly. Five days later, he was unable to stand or to void urine. A lung cancer was found in the right upper lobe. A spinal cord metastasis from the lung cancer was suspected from the neurologic and pulmonary findings. After 2 weeks, motor dysfunction and a total sensory deficit were observed below the lumbar region, and the patient developed pneumonia, which resulted in death. Autopsy showed an extensive intramedullary metastasis at the third lumbar segment of the spinal cord. Histology revealed poorly differentiated adenocarcinoma of the lung.


Protein deficiency and excess lipid synergistically augmented lipid peroxidation in growing rats. The influence of dietary protein and lipid on superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (GSH) and tissue lipid peroxidation, as measured by thiobarbituric acid-reactive substances (TBARS), was investigated in post-weaning male Wistar rats, fed either a diet containing 5% or 20% corn oil with 5%, 10% or 20% soy protein isolate (SPI) for four weeks. TBARS concentrations in 5% corn oil group was highest in 5% SPI group for all organs, followed by 10 and 20% SPI groups in the liver and 10 and 20% SPI groups in other organs. High lipid diet significantly increased TBARS formation in the liver of 10% SPI group. The liver and kidney SOD and GPx activities were higher in 5% and 10% SPI groups than in 20% SPI group, suggesting an augmented formation of radical substrates for these enzymes in low protein groups. Organ GSH concentrations did not show a linear correlation with dietary protein level. These results suggest that protein deficiency along with high lipid intake accelerates the peroxidative damage of the tissues by increasing oxy-radical formations and/or decreasing the defense mechanism.


Human and experimental studies on renal eicosanoid response to long-term cadmium exposure. In order to assess the effects of long-term exposure to cadmium (Cd) on the renal metabolism of eicosanoids, the urinary excretion of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2 alpha), and thromboxane B2 (TXB2) was determined in 37 workers exposed to Cd and in female Sprague-Dawley rats given 100 ppm Cd in drinking water for 10 months. Urinary output of sodium and calcium was also determined. The Cd-exposed workers showed an increased urinary concentration of 6-keto-PGF1 alpha, PGE2, sodium, and calcium. The rise of 6-keto-PGF1 alpha was related to Cd levels in blood and weakly correlated with urinary sodium. Calcium in urine was not related to the concentration of the metal in blood and urine. A slight elevation in urinary TXB2 was also observed in workers with blood Cd higher than 5 micrograms/liter. After 10 months of exposure to Cd, female Sprague-Dawley rats presented an enhanced urinary excretion of albumin, transferrin, beta 2-microglobulin, sodium, and PGE2 in urine. The latter was significantly correlated with albuminuria and transferrinuria. In conclusion the results show that chronic exposure to Cd induces changes in the urinary excretion of some eicosanoids. The possible relation of these changes to Cd-induced kidney dysfunction are discussed.


Altered capillary filtration coefficient in parathion- and paraoxon-induced edema in isolated and perfused rabbit lungs. Changes in pulmonary endothelium permeability and in microvascular hemodynamics induced by parathion (Pth) and paraoxon (Pox), its active metabolite, were investigated in isolated, perfused rabbit lungs. Blood-free perfusate was recirculated through isolated and ventilated lungs in an isogravimetric state and in zone III conditions. The arterial/venous/double occlusion technique was used to divide the total vascular resistance (Rt) into four components: arterial, precapillary, postcapillary, and venous. The capillary filtration coefficient (Kfc) was evaluated by measuring the amount of fluid filtering through the endothelium when the arterial and venous pressures were suddenly increased. Pth and Pox induced pulmonary edema by increasing endothelium permeability without changing the hemodynamic parameters at any level of the vascular bed. The Kfc value increased progressively, reaching a maximum (Emax) 60 min after administration of organophosphate (558 +/- 65% (n = 5) and 707 +/- 109% (n = 5) of baseline values, for Pth and Pox, respectively). During the next 60 min, it decreased. The time course of Pox-induced changes in Kfc was similar to that obtained with Pth. The concentration-response curve (Emax) expressed as a percentage of the baseline value versus the logarithm of the molar Pth concentration, ranging from 2 x 10(-5) to 4 x 10(-4) M) was linear (y = 1661.1 + 327.3x, r = 0.89, p < 0.001, n = 14). Piperonyl butoxide (4 x 10(-4) M), an inhibitor of cytochrome P450, had a strong protective effect against Pth (4 x 10(-4) M)-induced alterations of endothelium permeability (n = 5, p < 0.001). The effects of Pox (4 x 10(-4) M) on Kfc were completely abolished by pretreatment with 10(-5) M atropine, as shown by the significantly lower Emax value recorded in atropine-pretreated lungs (129 +/- 33%, n = 4) than in Pox-treated lungs (707 +/- 109%, n = 5, p < 0.001). The effects of Pth, on the other hand, were only partially inhibited, since the Emax value recorded in atropine-pretreated lungs (196 +/- 20%, n = 4) remained significantly higher than that recorded for control lungs (129 +/- 15%; n = 5; p < 0.05). These results show that isolated and perfused rabbit lungs constitute an appropriate model for studying the direct pulmonary effects of organophosphates. The edema-inducing action of Pth depends on its activation by conversion to Pox in the lung tissue.(ABSTRACT TRUNCATED AT 400 WORDS)


A physiologically based pharmacokinetic model for nicotine disposition in the Sprague-Dawley rat. A physiologically based pharmacokinetic (PBPK) model was developed to describe the disposition of nicotine in the Sprague-Dawley (SD) rat. Parameters for the model were either obtained from the literature (blood flows, organ volumes) or determined experimentally (partition coefficients). Nicotine metabolism was defined in the liver compartment by the first-order rate constants KNC and KNP which control the rate of nicotine metabolism to cotinine and "polar metabolites" (PM), respectively. These rate constants were estimated by optimizing the model fit to pharmacokinetic data obtained by administering an intraarterial (S)-[5-3H]nicotine bolus of 0.1 mg/kg to 6 rats. Model simulations that optimized for the appearance of cotinine in plasma estimated KNC and KNP to be 75.8 and 24.3 hr-1, respectively. Use of these constants in the model allowed us to accurately predict nicotine plasma kinetics and the fraction of the dose eliminated by renal (8.5%) and metabolic (91.5%) clearance. To validate the model's ability to predict tissue kinetics of nicotine, 21 male SD rats were administered 0.1 mg/kg (S)-[5-3H]nicotine intraarterially. At seven time points following treatment, 3 rats were euthanized and tissues were removed and analyzed for nicotine. Model-predicted nicotine tissue kinetics were in agreement with those determined experimentally in muscle, liver, skin, fat, and kidney. The brain, heart, and lung exhibited nonlinear nicotine elimination, suggesting that saturable nicotinic binding sites may be important in nicotine disposition in these organs. Inclusion of saturable receptor binding expressions in the mathematical description of these compartments resulted in better agreement with the experimental data. The Bmax and KD estimated by model simulations for these tissues were brain, 0.009 and 0.12; lung, 0.039 and 2.0; and heart, 0.039 nmol/tissue and 0.12 nM, respectively. This PBPK model can successfully describe the tissue and plasma kinetics of nicotine in the SD rat and will be a useful tool for pharmacologic studies in humans and experimental animals that require insight into the plasma or tissue concentration-effect relationship.


Characterization of lewisite toxicity in isolated perfused skin. Lewisite (L) is a potent organic arsenical that causes rapid onset of pain and severe vesication on contact with epithelial tissues. The isolated perfused porcine skin flap (IPPSF) is an in vitro model that has shown potential as a model for cutaneous vesicant research. The objective of this study was to characterize IPPSF responses after topical exposure to six concentrations of L ranging from 0.07 to 5.0 mg/ml (n = 4/treatment plus controls). Biochemical markers of viability (glucose utilization (CGU) and lactate dehydrogenase (LDH) release), vascular resistance (VR), venous arsenic flux, and morphological parameters (light and electron microscopy) were evaluated. In addition, lewisite lesions were characterized at 1, 3, 5, and 8 hr after exposure (n = 4/time plus controls) using these morphological parameters, as well as enzyme histochemistry. Macroscopic and microscopic lesions caused by L exposure were dose related. Mild decreases in CGU were noted with the higher concentrations of L, while generally increased responses in LDH release and VR were seen. Marked increases in LDH activity were noted in the blister fluid of IPPSFs treated with 5.0 mg/ml of L. Also, significant cutaneous arsenic flux was noted at the 5.0 mg/ml dose of L. The formation of gross blisters, the location and characterization of epidermal-dermal junction separation, and the time course of lesion production paralleled the description of L-induced lesions in humans. The sensitivity of the IPPSF to L exposure and the similarity of lesions to those described for humans suggests that this model provides a relevant in vitro model with which to study mechanisms of chemical vesication and arsenic toxicity, as well as protective and therapeutic intervention for vesicant exposure.


Inhibition of calcium-dependent pathways of B-cell activation by DMBA. The purpose of the experiments described in these studies was to determine the effects of 7,12-dimethylbenz[a]anthracene (DMBA) on B-cell activation produced by anti-IgD antibodies and interleukin-4 (IL-4). B and T cells are known to share many of the same biochemical pathways for cell activation by mitogen and antigen receptors. Previous studies in this laboratory have shown that DMBA inhibits mitogen-induced Ca2+ mobilization in murine and human T cells and produces an increase in intracellular Ca2+ in resting cells. The results of the present studies demonstrate that DMBA increases Ca2+ in resting B cells and inhibits B cell activation produced by anti-IgD antibodies, as measured by mobilization of free intracellular Ca2+ and [3H]thymidine incorporation. The proliferative response of B cells to insolubilized anti-IgD was suppressed only when cells were preexposed to DMBA. In contrast, IL-4 pathways of B-cell activation were insensitive to inhibition by DMBA, even when cells were preexposed. The induction of Class II MHC antigen (Ia) antigens on B cells by IL-4 was also found to be insensitive to DMBA treatment. These results suggest that DMBA suppresses only Ca(2+)-dependent pathways of B cell activation and indicate that altered Ca2+ homeostasis may be responsible for immunosuppression induced by this agent.


Differences in pulmonary biochemical and inflammatory responses of rats and guinea pigs resulting from daytime or nighttime, single and repeated exposure to ozone. Rats and guinea pigs were exposed to 0.8 mg ozone (O3)/m3 (approximately 0.4 ppm) for 12 hr during the daytime, 12 hr during the nighttime, or continuously to investigate circadian variation in O3-induced pulmonary toxicity during single and repeated O3 exposures. Biomarkers in bronchoalveolar lavage (BAL) fluid and lung tissues were measured as indicators of biochemical and inflammatory responses. Nighttime O3 exposure of rats resulted in larger increases of protein, albumin, and inflammatory cells in BAL fluid compared to those after daytime O3 exposure and this daytime-nighttime difference was statistically significant (p < 0.05). Single daytime or nighttime O3 exposure of guinea pigs resulted in comparable increases of BAL fluid proteins and inflammatory cells without a daytime-nighttime difference. Nighttime and continuous O3 exposure of rats for 3 days resulted in comparable increases in lung antioxidant enzyme activities, both of which differed statistically from effects from daytime O3 exposures (p < 0.05). Continuous O3 exposure of guinea pigs for 3 days caused, in general, statistically larger increases in lung tissue parameters compared to nighttime O3 exposures (p < 0.05). These results suggest that the extent of O3-induced acute pulmonary biochemical and inflammatory responses is directly related to the level of physical and respiratory activity. For rats, effects from continuous O3 exposure appear to be controlled by the nighttime, physically active period. In guinea pigs, the comparable responses following daytime or nighttime O3 exposure seem in accordance with their random behavioral daily activity pattern. This study supports the view that physical activity-related increases in inhaled dose significantly enhance the pulmonary O3 responses.


Enantioselective induction of peroxisomal proliferation in CD-1 mice by leukotriene antagonists. The effects of a racemic leukotriene antagonist (MK-0571) and its component enantiomers (L-668,018 and L-668,019) on hepatic peroxisome proliferation were examined in mice, rats, and rhesus monkeys. Administration of racemic MK-0571 to mice resulted in increased liver weights, increased peroxisomal volume density, and a pleiotropic induction of characteristic peroxisomal and nonperoxisomal enzyme activities associated with peroxisomal proliferation. When the individual enantiomers of MK-0571 were administered to mice, a pronounced enantioselective induction of peroxisome proliferation was observed. Toxicokinetic studies showed that the levels of each enantiomer in the liver or plasma after separate administration were similar. Thus, the enantioselectivity in the induction of peroxisome proliferation could not be explained on the basis of pharmacokinetic differences between the enantiomers. The hepatic peroxisomal response of the rat to MK-0571 was greatly attenuated compared to the mouse. As has been seen with other peroxisome-proliferating agents, MK-0571 had no effect on either peroxisomal volume density or peroxisomal enzyme activity in monkeys. Due to the high degree of enantiomeric discrimination toward the induction of peroxisomal proliferation by these enantiomers, compounds of this type may prove useful as probes to examine the mechanisms by which peroxisomal proliferating agents induce their effects.


Pulmonary cellular effects in rats following aerosol exposures to ultrafine Kevlar aramid fibrils: evidence for biodegradability of inhaled fibrils. Previous chronic inhalation studies have shown that high concentrations of Kevlar fibrils produced fibrosis and cystic keratinizing tumors in rats following 2-year inhalation exposures. The current studies were undertaken to evaluate mechanisms and to assess the toxicity of inhaled Kevlar fibrils relative to other reference materials. Rats were exposed to ultrafine Kevlar fibers (fibrils) for 3 or 5 days at concentrations ranging from 600-1300 fibers/cc (gravimetric concentrations ranging from 2-13 mg/m3). A complete characterization of the fiber aerosol and dose was carried out. These measurements included gravimetric concentrations, mass median aerodynamic diameter, fiber number, and count median lengths and diameters of the aerosol. Following exposures, cells and fluids from groups of sham- and fiber-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, lactate dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) values were measured in BAL fluids at several time points postexposure. Alveolar macrophages were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy. The lungs of additional exposed animals were processed for deposition, cell labeling, retained dose, and lung clearance studies, as well as fiber dimensions (from digested lung tissue), histopathology, and transmission electron microscopy. Five-day exposures to Kevlar fibrils elicited a transient granulocytic inflammatory response with concomitant increases in BAL fluid levels of alkaline phosphatase, NAG, LDH, and protein. Unlike the data from silica and asbestos exposures where inflammation persisted, biochemical parameters returned to control levels at time intervals between 1 week and 1 month postexposure. Macrophage function in Kevlar-exposed alveolar macrophages was not significantly different from sham controls at any time period. Cell labeling studies were carried out immediately after exposure, as well as 1 week and 1 month postexposure. Increased pulmonary cell labeling was measured in terminal bronchiolar cells immediately after exposure but returned to control values 1 week later. Fiber clearance studies demonstrated a transient increase in the numbers of retained fibers at 1 week postexposure, with rapid clearance of fibers thereafter. The transient increase in the number of fibers could be due to transverse cleaving of the fibers, since the average lengths of retained fibers continued to decrease over time. In this regard, a progressive decrease in the mean lengths and diameters of inhaled fibers was measured over a 6-month postexposure period.(ABSTRACT TRUNCATED AT 400 WORDS)


Lead inhibits secretion of osteonectin/SPARC without significantly altering collagen or Hsp47 production in osteoblast-like ROS 17/2.8 cells. In an effort to better understand the consequences of lead (Pb2+) on skeletal growth, the effects of Pb2+ were investigated using ROS 17/2.8 bone-like cells in vitro. These studies revealed that Pb2+ (4.5 x 10(-6) M -4.5 x 10(-7) M) has little or no effect on cell shape except when added immediately following seeding of the cells. However, proliferation of ROS cells was inhibited, in the absence of serum, at concentrations of 4.5 x 10(-6) M Pb2+. Protein production was generally increased, however, the major structural protein of bone, type I collagen, production was only slightly altered. Following treatment of ROS cells with Pb2+, intracellular levels of the calcium-binding protein osteonectin/SPARC were increased. Osteonectin/SPARC secretion into the media was delayed or inhibited. Coincident with retention of osteonectin/SPARC there was a decrease in the levels of osteonectin/SPARC mRNA as determined by Northern analysis. These studies suggest that processes associated with osteonectin/SPARC translation and secretion are sensitive to Pb2+.


Metabolism of benzo[a]pyrene by murine splenic cell types. The objective of the present study was to determine which splenic cell type(s) of B6C3F1 mice was capable of metabolizing B(a)P. Separation of splenocytes based on density by centrifugation through discontinuous Percoll gradients along with immunomagnetic negative selection or antibody-mediated complement lysis was utilized to obtain highly enriched populations of splenocytes for B(a)P metabolism studies. Immunofluorescent cell staining in conjunction with flow cytometry and examination of Giemsa-stained cytospin cell preparations indicated that B- or T-cell populations of greater than 95% purity and an 80-90% pure population of splenic macrophages were routinely attained. Splenic cell populations were incubated with [3H]B(a)P for 24 hr. High-pressure liquid chromatography was used to separate and quantitate the B(a)P metabolites generated by the enriched splenic cell populations. The results of these studies demonstrate that the macrophage is the cell type responsible for the metabolism of B(a)P within the spleen. The major metabolites of B(a)P produced were as follows: an unidentified peak of polar metabolites containing polyhydroxylated metabolites, B(a)P-9,10-dihydroxy-9,10-dihydrodiol, and B(a)P-7,8-dihydroxy-7,8- dihydrodiol. Other splenic cell types examined, including B and T cells, polymorphonuclear cells, or the spleen capsule did not produce amounts of B(a)P metabolites significantly above background levels. Based on these findings, macrophages are the splenic cell types which metabolize B(a)P. As a result, macrophages may be the cell type targeted by B(a)P resulting in suppression of splenic humoral immune responses.


Evaluation of murine splenic cell type metabolism of benzo[a]pyrene and functionality in vitro following repeated in vivo exposure to benzo[a]pyrene. Recent studies have demonstrated that macrophages are the cell types capable of metabolizing benzo[a]pyrene (B(a)P) within the spleens of untreated mice. Since repeated exposure to B(a)P results in immunosuppression and B(a)P is known to induce cytochrome P450 levels, the first objective of this study was to investigate whether exposure of mice to B(a)P could increase the amounts of immunosuppressive B(a)P metabolites generated and/or alter the pattern of B(a)P metabolites formed by several different splenic cell types. Mice were dosed with a daily sc dose of 200 mg/kg B(a)P or vehicle for 4 days. Separation of splenocytes based on density by centrifugation through discontinuous Percoll gradients along with immunomagnetic negative selection or antibody-mediated complement lysis was used to obtain different splenic cell populations. Cells were incubated with [3H]B(a)P for 24 hr. High-pressure liquid chromatography was used to separate and quantitate B(a)P metabolites. Results indicate that splenic macrophages of B(a)P-treated mice produced significantly greater amounts of some metabolites compared to those of vehicle-treated mice. The three major metabolites produced were an unidentified peak of polar metabolites containing polyhydroxylated metabolites, B(a)P-9,10- and B(a)P-7,8-dihydrodiols. Other splenic cell types examined did not produce metabolite amounts significantly above (T-cells, PMNs, or the capsule) or just above (B-cells) background. The second objective was to investigate the splenic cell type(s) targeted by B(a)P resulting in suppression of humoral immunity. Separation-reconstitution studies along with in vitro sensitization techniques with several different antigens (sheep red blood cells (SRBC), dinitrophenyl-Ficoll (DNP-Ficoll), lipopolysaccharide (LPS)) were used to identify splenic target cells following exposure of mice to B(a)P (200 mg/kg/day, sc for 4 days). Findings indicate that in vitro plaque-forming cell (PFC) suppression was due to alterations in the adherent (macrophage) cell population. Exposure also suppressed the PFC response to the T-dependent antigen SRBC and the T-independent antigen DNP-Ficoll, but did not suppress the PFC response to the polyclonal antigen, LPS. These data suggest that B(a)P is targeting macrophages.


Possible models for multiple chemical sensitivity: conceptual issues and role of the limbic system. Conceivably, chemicals contacting olfactory nerve projections in the nose could either be transported into or relay electrical signals to the limbic region, leading to a vast array of symptoms. Likewise, thought processes and mood states may trigger or interrupt pre-existing limbic activity. At present, however, no evidence suggests that limbic activity triggered by environmental exposures can be entirely overcome by psychologic interventions. One important ramification of a limbic hypothesis, if true, is that no convenient biologic marker for multiple chemical sensitivity may exist at the present time. Ten years from now, we may finally confirm the existence of multiple chemical sensitivities (by careful, blinded challenges) but still have no single mechanism to explain it; that is, after all avenues of biochemical and immunologic inquiry have been exhausted, no single cause or marker for this disorder may be apparent. The theory that adaptation plays a role in MCS is based on the observed responses of patients in a deadapted state who have been housed in an environmental unit. Although adaptation is only an observation at this time, not a mechanism, biologic limits might regulate how much an organism can adapt. Such limits could be highly individual and vary by orders of magnitude. Certainly adaptation occurs at all levels of biologic systems, from enzyme systems to cells, tissues, organs, and even behavior (Fregly, 1969). Theoretically, a major insult or the accumulation of lower-level injuries within these systems could lead to a kind of "overload" or "saturation" effect with respect to adaptive capacity. This might cause an individual to have environmental responses, which, instead of being flexible and fluid, would become fragile and overly responsive. Many MCS patients report that years, and in some cases decades, after the onset of their problems, they have recovered only a portion of their former energies and tolerance for their environment. Their descriptions seem to suggest the loss of an intangible capacity to adapt, parts of which may be temporary and recoverable and other parts of which may not. Perhaps our patients have been telling us the diagnosis.


History and clinical presentation of the chemically sensitive patient. Although no one has all the answers to the mystery of chemical sensitivity, the reality of this condition, most recently called multiple chemical sensitivities, is not in doubt. Evidence is increasing of its possible physiologic mechanisms, which will be discussed later in this volume. From the evidence and from personal and professional experience, the author believes that chemical sensitivity is not a diagnosis of exclusion, and that fixed-name diseases may have environmental triggers or complicating factors (Rea, 1990b). With appropriate preparation and environmental controls, MCS can be investigated and diagnosed in a scientific and reproducible manner.


Effects of amiodarone administration during lactation in Fischer-344 rats. The antiarrhythmic drug, amiodarone, was administered (35 mg/kg, p.o.) once daily to lactating Fischer-344 rats for either the first 7 days of lactation, the first 14 days of lactation, or for the full 24-day lactational period. Treatment with amiodarone resulted in a decrease in maternal weight gain compared to pair-fed vehicle-treated controls, however, neonatal weight gain was not affected. The concentration of amiodarone in the maternal milk was approx. 6-fold higher than its primary metabolite, desethylamiodarone. Plasma levels of amiodarone and desethylamiodarone were higher in maternal rats compared to neonates. Both amiodarone and desethylamiodarone were distributed to neonatal tissues through lactational transfer. The levels of desethylamiodarone were higher in neonatal lung compared to liver at all treatment times. They were also elevated above amiodarone in neonatal lung at all treatment times. The amiodarone levels in neonatal lung and liver were similar.


Multiple chemical sensitivity: treatment and followup with avoidance and control of chemical exposures. Reducing unnecessary chemical exposures, particularly pesticides and other petrochemicals, shows promise for reducing illness episodes in the chemically sensitive. Because similar types of exposures have been associated with the onset of chemical sensitivity, such precautions could have wider preventive value for the rest of society as well. Many uses of chemicals have dubious social benefits, and reduced use should be achievable. The chemical industry will likely bitterly contest the reduced use of chemicals because it stands to lose substantial sales. Compensation and liability insurance carriers also stand to lose if the environment is found problematic, rather than individual psychology, for example. Professionals should also recognize conflicts of interest for the chemical and insurance industries by openly acknowledging funding sources for research. The author believes that research on chemical sensitivity that blames the psyche of the victim rather than the chemical will more likely be funded by the insurance or chemical industry than will other research. Study designs should be developed in an atmosphere removed from financial conflicts of interest. This means a substantially larger role for government funding of research on chemical sensitivity to avoid biasing the knowledge base by financially interested parties. The time is critical for government funding of research on chemical sensitivity because the illness is being defined and characterized. If preliminary research is flawed by improper design and focus, our understanding of the problem could be delayed for years.


Studies of the amplification of carbaryl toxicity by various oximes. The administration of 2-pyridine aldoxime methyl chloride (2-PAM Cl) is a standard part of the regimen for treatment of human overexposure to many organophosphorus pesticides and nerve agents. However, some literature references indicate that poisoning by carbaryl (1-naphthyl N-methyl carbamate), an insecticide in everyday use, is aggravated by the administration of 2-PAM Cl. This effect has been reported in the mouse, rat, dog and man. We have found that the inhibition of both eel acetylcholinesterase (eel AChE, EC 3.1.1.7) and human serum cholinesterase (human BuChE, EC 3.1.1.8) by carbaryl was enhanced by several oximes. Based on 95% confidence limits the rank order of potentiation with eel AChE was TMB-4 = Toxogonin > HS-6 = HI-6 > 2-PAM Cl. By the same criterion, the rank order of potentiation with human BuChE was TMB-4 > Toxogonin > HS-6 = 2-PAM Cl. Carbaryl-challenged mice also reflected a potentiation since TMB-4 exacerbated the toxicity more than 2-PAM Cl. Our hypothesis is that certain oximes act as allosteric effectors of cholinesterases in carbaryl poisoning, resulting in enhanced inhibition rates and potentiation of carbaryl toxicity.


Treatment options in multiple chemical sensitivity. The essential features of treatment for chemical sensitivity are: 1) Encouraging the provision of clean air, food, water, and surroundings. 2) Identifying substances to which the patient is sensitive, with subsequent a) enhanced avoidance, or b) specific immunotherapy to reduce the patient's reactivity to those substances. 3) Assessing and enhancing the patient's nutritional status to maximize the body's ability to detoxify and to minimize the free-radical production and oxidative stress of xenobiotics. 4) Addressing concurrent problems such as infections, immunosuppression, and other medical conditions in an appropriate fashion. 5) Evaluating the patient's psychologic status and addressing any social and emotional problems in a compassionate manner. The author believes that multiple chemical sensitivity is a real condition with documented physiologic abnormalities. It is not a functional or psychologic illness or a belief system of the patient. Second, this condition is diagnosable and treatable by various means. These treatment options not only make common sense but usually result in significant improvement for these unfortunate patients, who deserve the very best efforts of their health care providers.


Dietary pyrrolizidine (Senecio) alkaloids and tissue distribution of copper and vitamin A in broiler chickens. The effect of feeding a diet containing 5% tansy ragwort (TR) (Senecio jacobaea), a poisonous plant containing pyrrolizidine alkaloids (PA), on the blood and liver levels of copper, zinc, iron and vitamin A in broiler chicks was examined. Serum and liver copper and liver iron concentrations were increased in chicks fed a diet with 5% TR, while serum and liver zinc and vitamin A decreased. When PA were removed from the diet, partial restoration of normal serum vitamin A level occurred, indicating that the ability to mobilize liver vitamin A is not irreversibly inhibited by PA. The decline in serum vitamin A occurred by 8 days of TR feeding with a concurrent decline in growth rate. When chicks were fed a diet high in vitamin A (25,000 IU/kg), followed by a basal diet containing TR, serum vitamin A levels were significantly (P < 0.01) decreased, while liver vitamin A level increased. This indicates that mobilization of previously stored vitamin A from the liver is impaired by PA. Prior feeding of a high vitamin A level resulted in protective effects against PA toxicity, as assessed by histopathology. This study shows that a dietary source of PA modifies metabolism and tissue distribution of minerals and vitamin A.


Effect of preperfusion of ascending concentrations of lead on digoxin-induced cardiac arrest in isolated frog heart. The present work investigated the effect of preperfusion of ascending concentrations of lead acetate (LA) (10(-9), 10(-7) and 10(-5) M) on digoxin (DGN) cardiotoxicity in isolated frog heart, in order to look for any consequent variations in its lead-induced potentiation. The DGN perfusion time(s) and DGN exposure (micrograms DGN/10 mg heart weight) for, and myocardial DGN level (ng DGN/g wet tissue) at, cardiac arrest were the parameters evaluated so as to assess cardiotoxicity. Both sodium acetate and LA (10(-7) M) preperfusion led to a diminution in cardiac rate at 10 min of DGN perfusion without altering the contractility compared to the DGN alone group. With regard to DGN perfusion time for cardiac arrest, preperfusion of ascending concentrations of LA induced a corresponding decrease which was statistically significant (P < 0.05). On the other hand, in the experimental group that received preperfusion of 10(-9) M LA, the DGN exposure for cardiac arrest was not significantly different from that of the control, whereas in the 10(-7) and 10(-5) M groups, it was significantly lower (P < 0.05). In the experimental group that received preperfusion of 10(-7) M LA, the significant reduction in DGN perfusion time and DGN exposure was well corroborated by a diminution in the myocardial DGN level (4.01 +/- 0.17 ng/g wet tissue in comparison with the control value of 5.72 +/- 0.4 ng/g wet tissue, P < 0.05) at cardiac arrest. Taken together, these data reveal that with the preperfusion of LA in ascending concentrations, there is a relative increase in LA-induced potentiation of DGN cardiotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)


Multiple chemical sensitivities: a practicing clinician's point of view. Clinical and immunologic research findings. The multiple chemical sensitivities syndrome is a symptom complex characterized by emotional depression, short-term memory loss, acquired intolerance to environmental agents such as aerosolized petrochemicals and foods, and alteration in metabolic rate associated with increased body mass. This syndrome can be caused by multiple etiologic agents. With careful evaluation, it is rare that a causal agent can not be identified in this syndrome. Our treatment regimens include combinations of diet and environment control as well as antiviral, antifungal, and immune modulator therapy. We find that the majority of patients can, through time and appropriate treatment, be restored to a normal and productive lives.


Morphological changes in the respiratory system of mice after inhalation of mosquito-coil smoke. Male ICR mice were exposed to mosquito-coil smoke with d-allethrin or without d-allethrin at airborne particles concentration of 1.27 mg/m3, 7 h/day, 7 days/week for 1, 3, 6, and 12 months. Additional groups of air exposure animals served as controls. At 1 month after exposure, the histopathological lesions included the loss of cilia, and the alteration of the alveolar pattern in the treated and the sham mice. Volume fractions of the type I and II cells were smaller (0.028 +/- 0.006, 0.044 +/- 0.002) in the treated group than those of the controls (0.049 +/- 0.008, 0.059 +/- 0.003). Fractions of the lumina of vessels and the vessel wall decreased in both the treated and the sham groups as compared to the control group. However, the volume fraction of alveolar air space increased significantly in both treated and sham groups as compared to the controls (0.619 +/- 0.022, 0.685 +/- 0.018 vs. 0.507 +/- 0.025). After 3- and 6-months exposure, the lesions observed in the trachea persisted. The intercellular fibrosis in the lung was increased in both the treated and sham groups at 6 months and became more severe at the later stages. At 12-months exposure, an increase in vascularity of the alveolar wall was observed and fine granular debris was frequently present in the alveolar space. The fraction volumes of the type II cells in the treated group and the type I cells in the sham group were significantly increased (0.059 +/- 0.010, 0.042 +/- 0.003) compared with those of the controls (0.038 +/- 0.008, 0.033 +/- 0.003). However, the fraction volume of air space and vessel lumen were not different among the three groups. Finally, there were no differences in the morphologic appearance of the airways and the lung periphery between the treated and the sham-exposed animals.


Development of multiple chemical sensitivity after an outbreak of sick-building syndrome. Investigation of this outbreak raises some important points for future research. Although for various reasons the case ascertainment for MCS was not complete, the three MCS patients described here all had preexisting conditions that may have put them at risk. In addition, one person among the 20 described had chronic fatigue syndrome but did not develop MCS. Many of the persons described here continue to have ongoing complaints that are not MCS. Significant exacerbation of preexisting allergic disease and new onset of asthma occurred among those patients. As a group, they did not recover completely after the outbreak; several are no longer working in the building but in alternative work spaces. An important distinction should be made between individuals who met the definition used here for MCS and others who had significant exacerbation of some better-defined illness brought on by building conditions. New onset of MCS was a partial but not complete explanation of the clinical course for this group of 20 persons.


Combined effect of cadmium and nickel on rat hepatic monooxygenases: possible stimulation of certain cytochrome P-450 isozymes. When male rats were given either a single dose of cadmium (3.58 mg CdCl2.6H2O/kg, i.p.) 72 h prior to sacrifice or a single dose of nickel (59.5 mg NiCl2.6H2O/kg, s.c.) 16 h prior to sacrifice, the activities of ethylmorphine N-demethylase, aminopyrine N-demethylase and aniline 4-hydroxylase, and the levels of cytochrome P-450 and microsomal heme were significantly decreased. Cadmium decreased the cytochrome b5 level significantly, whereas it did not alter the NADPH-cytochrome c reductase activity significantly. In contrast, Ni did not alter the cytochrome b5 level significantly but decreased the NADPH-cytochrome c reductase activity significantly. For the combined treatment, animals received the single dose of nickel 56 h after the single dose of cadmium and then they were killed 16 h later. In these animals ethylmorphine N-demethylase, aminopyrine N-demethylase and NADPH-cytochrome c reductase activities and cytochromes P-450 and b5 levels increased significantly as compared to those of controls, whereas aniline 4-hydroxylase activity and microsomal heme level remained unaltered. In concordance with the increase in the enzyme activities, certain P-450 protein bands were observed to be elevated when studied on SDS-polyacrylamide gel electrophoresis. Furthermore, when the monooxygenase activities and SDS-polyacrylamide gel electrophoresis profiles of combined metal-treated animals were compared with those of the animals treated with classic inducers such as phenobarbital (75 mg/kg i.p., 72, 48 and 24 h prior to sacrifice) and 3-methylcholanthrene (20 mg/kg i.p., 72, 48 and 24 h prior to sacrifice), the combination of metals seemed to have tendency to stimulate certain phenobarbital and 3-methylcholanthrene inducible cytochrome P-450 isozymes.


The metabolism of 1,3-dinitrobenzene by rat testicular subcellular fractions. The metabolism of 1,3-dinitrobenzene by rat testicular subcellular fractions (microsomes, cytosol or 9000 x g supernatant (S-9)) was studied. The effects of NADPH, oxygen, glutathione (GSH) and carbon monoxide upon the rate of metabolism were determined. Three metabolites were identified, and characterised as 3-nitrosonitrobenzene, 3-nitrophenylhydroxylamine and 3-nitroaniline by co-chromatography with authentic standards. These findings indicate the presence of an inherent enzyme system capable of facilitating nitro-reduction in the testes. The implications of these findings to the mechanism of 1,3-DNB-induced testicular toxicity are discussed.


Carcinogenicity assessment of lonidamine by dietary administration to Sprague-Dawley rats. Following chronic dietary administration of 20, 60 and 180 mg/kg per day of lonidamine for 2 years to groups of Sprague-Dawley rats, treatment-related non-tumour findings seen microscopically included the following: atrophy of the testis with associated changes in epididymis and pituitary at all dosages; neuropathy in the sciatic nerve accompanied by skeletal muscle atrophy which was dose-related, particularly in male animals. Neither the incidence of tumour-bearing animals, nor the spectrum of tumours seen, was significantly changed. In the females given 180 mg/kg per day an overall reduction in tumour incidence was noted, which was reflected in a significant reduction (P < 0.001) in mammary tumours.


Subchronic toxicity study of peppermint oil in rats. Peppermint oil was given p.o. to four groups of 28 rats at dosage levels of 0, 10, 40, and 100 mg/kg body wt. per day for 90 days. At the highest dose histopathological changes consisting of cyst-like spaces scattered in the white matter of cerebellum were seen. No other signs of encephalopathy were observed. Nephropathy was seen in the male rats in the highest dose group. A no-observed-adverse-effect level of 40 mg/kg body wt. per day was determined.


Covalent binding of ethylene dibromide and its metabolites to albumin. The present study was undertaken to determine covalent binding of [1,2-14C]ethylene dibromide (EDB) to albumin under in vivo and in vitro conditions. For the in vivo covalent binding, 25 mg/kg body weight of [1,2-14C]EDB was given daily to male rats for 12 consecutive days and the animals were sacrificed at 24 h following the last dose. Blood was withdrawn from inferior vena cava in heparinized tubes and plasma was separated, dialyzed against ice-cold 10 mM phosphate buffer (pH 7.4) and then subjected to size-exclusion high-performance liquid chromatography (SE-HPLC). A major radioactive peak eluted at an elution volume corresponding to 65,000 dalton molecular mass was found to be associated to albumin at a level of 0.14 nmol equivalent EDB/mg protein. For the in vitro covalent binding, human plasma or purified albumin was incubated with [1,2-14C]EDB in the presence of phenobarbital-treated rat liver microsomes and NADPH-generating system for 2 h at 37 degrees C. The 100,000 x g supernatant of the incubation mixture was dialyzed extensively and analyzed as described for the in vivo studies. Approximately 0.28 nmol equivalent EDB/mg protein was found to be associated to albumin (about 2-fold higher than the in vivo binding). Binding of 14C-label to albumin under in vivo and in vitro conditions was further supported by the affinity chromatography of albumin fraction isolated by SE-HPLC. Reversed-phase HPLC analysis of pronase digest of the albumin obtained from in vitro studies indicated formation of several amino acid adducts of EDB and/or its metabolites. Structure elucidation of such amino acid adducts will be helpful in developing a relatively non-invasive method of measuring the EDB exposure.


Co-exposure to gasoline vapor decreases benzene metabolism in Fischer-344 rats. The metabolic interactions of benzene and gasoline vapor were investigated in male Fischer-344 rats. A closed chamber gas-uptake exposure system was used to obtain inhalation uptake curves for benzene alone and benzene in the presence of gasoline vapor. Exposure to benzene as a component of gasoline vapor resulted in a decrease of benzene metabolism. A physiologically based pharmacokinetic model of benzene metabolism was used to quantitatively determine the extent of the inhibitory effect of gasoline vapor on benzene metabolism. This observed inhibitory effect cannot be accounted for by the presence of toluene in gasoline vapor.


Inhibition of human hepatic glutathione S-transferase isozymes by ethacrynic acid and its metabolites. The comparative inhibition of ethacrynic acid (EA) and its known metabolites against glutathione S-transferase (GST) was investigated using human livers procured from kidney donors. EA and all three metabolites of EA had an inhibitory effect against conjugation between 1-chloro-2,4-dinitrobenzene (CDNB) and glutathione (GSH). The GSH adduct of EA (EA-GSH) was the most potent inhibitor of GSTs; EA-GSH was approximately one order of magnitude more potent than the parent EA, while L-cysteine conjugate of EA (EA-cysteine) and N-acetyl-L-cysteine conjugate of EA (EA-mercapturate) were approximately two orders of magnitude less potent than the parent EA. Further metabolism of EA-GSH conjugate is suggested to be a detoxification process in terms of GST activities.


In vitro hydrolysis of methyl acetate, a limitation in application of head-space gas-chromatography in biological monitoring of exposure. Stoichiometric conversion of methyl acetate to methanol in vitro was detected when methyl acetate was incubated with blood for 2 to 8 h. The velocity of the reaction was so fast that almost all of methyl acetate disappeared in 8 h. The methanol formation was further confirmed by means of gas-chromatography-mass spectrometry. The capacity to hydrolyze methyl acetate was evenly distributed in cellular and noncellular fractions of blood, but not in urine. The significance of the observation is discussed in relation to biological monitoring of exposure to industrial ester solvents by means of head-space gas-chromatography of blood samples.


Benzo[a]pyrene and nicotine impair epidermal growth factor mediated cellular functions of buccal mucosa. This study investigated the effect of two major ingredients in cigarette smoke, benzo[a]pyrene (BP) and nicotine, on epidermal growth factor (EGF) receptor binding and EGF-mediated cellular functions in rat buccal mucosa. Rat buccal tissue was incubated in DMEM in the absence (control) and presence of 10 microM BP or nicotine for 2.5 h at 25 degrees C. There were no significant differences in [125I]EGF binding to the buccal mucosal membranes between the control and treatment groups. Protein tyrosine kinase assay showed that EGF stimulated phosphorylation of a 170-kDa protein band in the controls, but not in the BP- and nicotine-treated samples. The basal [3H]thymidine incorporations were not significantly different between the groups. Nevertheless, addition of 5 nM EGF increased [3H]thymidine incorporation by 22% in the control, but not in the BP- or nicotine-treated group. The results demonstrate that BP and nicotine change the buccal mucosal functions associated with alteration of EGF receptor.


Endocrine pancreas in the postnatal offspring of alloxan diabetic rats. This study was conducted to investigate the morphological changes in the postnatal pancreatic islets in offspring of diabetic rats. Diabetes was induced in female Sprague Dawley rats by intravenous injection of alloxan (40 mg/kg). After 1 week, rats with blood sugar above 270 mg% were bred and watched until spontaneous delivery occurred. Litters in the following age groups were sacrificed by decapitation, 0, 8, 24, 72 and 168 h, and compared with their controls. Blood sugar levels were significantly higher in the neonates of diabetic mothers immediately after delivery compared to the control, then became normal after 8 h. Islets of the offspring of the diabetics at birth showed weak positive staining for insulin using immunocytochemical techniques. By 72 h some cells showed immunopositive staining similar to the control, while at 168 h all the beta (B) cells were stained normally. Beta cells of the islets from the diabetic series at birth were almost completely degranulated except for scattered granules toward the periphery. Their cytoplasm exhibited glycogen and lipid accumulations. Cells also showed signs of hyperfunction in the form of an extensive endoplasmic reticulum and well-developed Golgi complex with distended Golgi cisternae. At 8 h postnatally the population of pale secretory granules was markedly increased. The changes described at birth persisted at 24 h and, to a lesser extent, 72 h after delivery. At the age of 1 week, the beta cells appeared to be normal.


Rates of ethyl acrylate binding to glutathione and protein. Ethyl acrylate is a monomer used extensively in polymer manufacturing. Although ethyl acrylate is toxic at high concentrations, it is metabolized and detoxified rapidly at low concentrations. In the current studies, in vitro experiments have demonstrated that [14C]ethyl acrylate reacts with both glutathione (GSH) and protein to give either [14C]3-(glutathion-S-yl)ethylpropionate or covalently bound protein adducts, respectively. The second-order rate constant for [14C]ethyl acrylate conjugation with GSH was determined by quantification of [14C]3-(glutathion-S-yl)ethylpropionate using an HPLC system equipped with a flow-through radioactive detector. The rate constant for conjugation was 32.8 M-1 min-1. Additionally, the apparent second-order rate constants were determined for [14C]ethyl acrylate binding to the protein fraction of 14 whole tissue homogenates. Estimation of total protein binding sites was performed by reacting tissue homogenates with high concentrations of [14C]ethyl acrylate, while rates of binding were determined by reacting tissue homogenates with 200 microM [14C]ethyl acrylate at 37 degrees C for various periods of time. Apparent second-order rate constants for ethyl acrylate binding to protein homogenates were similar to that observed for GSH reacting with ethyl acrylate. The role of GSH-transferase in catalyzing 3-(glutathion-S-yl)ethylpropionate formation also was evaluated with whole tissue homogenates. In most tissues, the GSH-transferases poorly catalyzed the conjugation reaction. However, a significant increase in 3-(glutathion-S-yl)ethylpropionate formation was observed with liver homogenate.


Inhibition of acetaminophen hepatotoxicity by acetaldehyde in the rat. Since we have observed that acetaldehyde, an oxidative metabolite of ethanol, inhibits acetaminophen activation in rat liver microsomes, the in vivo effect of acetaldehyde on acetaminophen hepatotoxicity was tested. In vivo experiments in 3-methylcholanthrene-pretreated male Sprague-Dawley rats showed that administration of cyanamide (20 mg/kg, i.p.) and acetaldehyde (600 mg/kg, s.c.) given 3 and 1 h, respectively, prior to acetaminophen (500 mg/kg, i.p.) but not cyanamide alone prevented acetaminophen hepatotoxicity as assessed by serum transaminases and histology. Acetaldehyde may partly be responsible for the inhibitory effect of ethanol on acetaminophen hepatotoxicity.


Mechanism of the increase in lipid peroxide induced by cisplatin in the kidneys of rats. To clarify the mechanism where by cisplatin induces increases in lipid peroxide, we examined the effects of antioxidants on changes in the activity of lipid peroxidation protecting enzymes in the kidneys of rats after cisplatin administration. alpha-Tocopherol and glutathione (GSH) significantly depressed lipid peroxidation in the kidneys of cisplatin-treated rats on the 4th day after cisplatin administration, and GSH depressed the increases in blood urea nitrogen levels induced by cisplatin. Thus, GSH appeared to reduce cisplatin-induced nephrotoxicity. However, alpha-tocopherol and GSH had no effect on the significant decrease in the activity of lipid peroxidation protecting enzymes induced in the kidney after cisplatin treatment. These results showed that lipid peroxide produced by cisplatin had no effect on these enzymes, suggesting that the increases of lipid peroxide were a result of the cisplatin-induced reduction in the activity of these enzymes.


Endrin-induced production of nitric oxide by rat peritoneal macrophages. The effect of oral endrin administration to rats on the production of nitric oxide (NO) by peritoneal macrophages was investigated. Nitric oxide formation was measured as nitrite. Endrin (4.5 mg/kg) enhanced the secretion of NO by approx. 300%. The effect of endrin on NO formation was both dose- and time-dependent. Ellagic acid, which has been shown to be a potent antioxidant, inhibited the elevation of NO production induced by endrin. These results suggest that the toxicity of endrin may at least in part be due to the production of an oxidative stress.


Wy-14,643 stimulates hepatic protein kinase C activity. The mechanism by which hypolipidemic drugs and industrial plasticizers cause hepatic tumors in rodents remains unknown. Protein kinase C is elevated during hepatic cell turnover, and sustained cellular replication has been shown to correlate with an increase in hepatic tumors. Therefore, the effect of [4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio]acetic acid (Wy-14,643) on protein kinase C activity was examined. Female Sprague-Dawley rats were given 100 mg/kg Wy-14,643 in olive oil (i.g.), while control rats received equal volumes of oil vehicle. After 24 h, the activity of protein kinase C was estimated in isolated hepatic fractions by measuring the binding of 3H-phorbol-12,13-dibutyrate, a specific ligand for protein kinase C. Administration of Wy-14,643 significantly increased protein kinase C activity nearly 2-fold in microsomal fractions. Thus, it is possible that Wy-14,643 increases cell proliferation and causes tumors by mechanisms involving protein kinase C.


Criterion of reliability as the function of variability and significance of biological parameters. A differentiated approach to the choice of criterion of reliability in toxicological studies is recommended. This approach is based on quantitative assessment of variability of biological parameters using the variation coefficient. All biological parameters are classified into rigid, flexible and high-flexible ones. The establishment of the biological significance of various parameters and assessment of the degree of their deviation allows the detection of prepathological changes in the body state, this being of importance for a more accurate LOAEL and NOAEL determination.


Protective effect of copper against cadmium cytotoxicity on cultured vascular endothelial cells. We investigated the effect of copper on cadmium-induced cytotoxicity on vascular endothelial cells from bovine aorta in a culture system. Cytotoxicity was evaluated by the [3H]adenine release assay and the histological observation. After a 24-h incubation, cadmium exhibited a significant cytotoxicity on confluent cultures of endothelial cells in a dose-dependent manner, while copper only slightly did after a 24-h incubation. It was found that copper (5 microM) significantly decreased cadmium (1 and 2 microM) cytotoxicity; histologically, formation of de-endothelialized areas in the cell layer caused by cadmium was reduced by copper. The accumulation of cadmium in the cell layer was significantly decreased by copper; however, that of copper was unaffected by cadmium. It was therefore suggested that copper significantly protects cadmium-induced cytotoxicity on cultured endothelial cells primarily through decreasing the cellular cadmium accumulation.


Mutagenicity of nitroxyl compounds: structure-activity relationships. Three piperidinoxyl radicals were found to be directly mutagenic in Salmonella typhimurium TA 100, one pyrrolidinoxyl compound had weaker activity, and two other pyrrolidinoxyl derivatives did not produce an increase of the spontaneous revertants. The tester strain TA 100 was selected in preliminary tests for its higher sensitivity compared to TA 98 and TA 102. The mutagenic activity of the three active compounds was abolished by partial reduction with ascorbic acid, suggesting that the mutagenicity was linked to the free radical nature of these compounds, and reduced in the presence of a cofactor supplemented rat liver subcellular fraction. The mutagenicity of the tested compounds was correlated to the resistance of the nitroxyl spin labels to reduction: the more reactive radicals were found to possess higher mutagenic activity.


Detection of sulphur-conjugated pyrrolic metabolites in blood and fresh or fixed liver tissue from rats given a variety of toxic pyrrolizidine alkaloids. Rats were given single injections of hepatotoxic pyrrolizidine alkaloids and killed after 30 h. Sulphur-bound pyrrolic metabolites from the alkaloids in samples of their blood or liver tissue were converted to extractable ethyl ethers of low molecular weight for detection and identification using TLC, HPLC or GC-MS. Liver samples were also preserved as an acetone-washed powder or in formalin-based fixative before being later subjected to similar analyses. S-Bound pyrrolic metabolites were identified in samples from rats given all the types of alkaloid tested, which included mono-esters (heliotrine, indicine), a diester (lasiocarpine), and macrocyclic diesters (retrorsine, senecionine). The pattern of pyrrolic metabolites from the crotanecine-based alkaloid anacrotine differed and could be distinguished from retronecine- or heliotridine-based alkaloids. Whereas the alkaloids tested ranged widely in toxicity, single doses of 0.25 x acute LD50 or more led to detectable metabolites. Liver pyrroles remained detectable in fixed or powdered samples preserved for long periods. Similar tests on rats given monocrotaline continuously in their drinking water (20 mg/l) led to detectable pyrroles in blood after 12 days (total intake approx. 27 mg/kg) and in liver after 25 days. The metabolites remained detectable in rats killed 17 days after the alkaloid exposure was discontinued. The simple procedures described are applicable to the diagnosis of pyrrolizidine alkaloid exposure in livestock, using fresh or dried blood or fresh or preserved liver samples. They bring to pyrrolizidine toxicology for the first time the capability to demonstrate chemically that livestock (or people) have been exposed to these alkaloids many days or weeks previously.


Sex differences in the bioavailability of soil-adsorbed m-xylene in orally exposed rats. The bioavailability of soil-adsorbed m-xylene was assessed in male and female rats gavaged with an aqueous suspension of 14C-m-xylene alone or adsorbed to sandy or clay soil. Sex-related differences were observed in the rate and the amount of m-xylene-derived radioactivity absorbed and excreted in the presence of the soils. A higher peak plasma concentration of radioactivity was observed in females following treatment with sandy soil-adsorbed m-xylene. Further, sandy and clay soil-adsorbed chemicals demonstrated significantly longer absorption half-lives (t1/2), while sandy soil produced a shorter elimination t1/2 vs. m-xylene alone in female rats. Increased bioavailability of sandy soil-adsorbed m-xylene in females was evidenced by a significantly increased area under the plasma concentration time curve (AUC). Neither of the soils altered the maximum plasma concentration, the rate at which xylene-derived radioactivity was absorbed or eliminated, or the AUC in male rats. Fat contained the highest tissue concentration of xylene-derived radioactivity in all treatment groups of both sexes. Further, in all male and female treatment groups m-xylene was primarily metabolized and excreted in urine with methyl hippuric acid identified as the main urinary metabolite. Sandy soil slightly delayed urinary excretion in females while both soils increased expired air excretion in males compared to m-xylene alone. Methylhippuric acid was the main urinary metabolite in all groups.


Pentamidine isethionate is negative in tests for microbial mutagenicity and chromosomal breakage in vitro. Pentamidine isethionate, a drug used for the treatment of Pneumocystis carinii pneumonia in AIDS patients, was assayed for mutagenicity in five strains of Salmonella typhimurium and for clastogenicity and mutagen-induced chromosomal breakage in five human lymphoblastoid cell lines. The mutagenicity assay employed both repair-deficient and repair-positive strains without and with the addition of rat liver S-9. There was no indication of a mutagenic response in any of the strains of Salmonella. Chromosomal breakage was measured in lymphoblastoid cell lines, both in the absence and presence of bleomycin. Following 2, 5 and 24 h of treatment, pentamidine alone did not induce clastogenicity, nor was there an increase in chromosomal breakage when the cell lines were treated with bleomycin simultaneously with, or 22 h prior to, the addition of pentamidine. From these data it can be concluded that pentamidine is not mutagenic or clastogenic in the two assays employed in this study.


Kinetics of aluminum in rats. IV: Blood and cerebrospinal fluid kinetics. Aluminum causes central nervous system (CNS) toxicities in both humans and various animal species. Although blood aluminum concentrations are monitored in the clinic, very little is known regarding the relationship between such concentrations and corresponding CNS aluminum content. As a first step in that direction, this study was undertaken to simultaneously determine blood and CSF kinetics of this element. Following intravenous injection of aluminum (1 mg/kg), there was a rapid (within 30 min, post injection) increase in CSF aluminum; peak concentrations (38-45 ng/ml) were achieved between 2-3 h. While peak blood aluminum concentrations increased about 58-fold from the pre-dose value (from 256 +/- 120 to 14,730 +/- 388 ng/ml), corresponding increases in CSF aluminum were only about 20-fold. Blood and CSF aluminum concentrations declined monoexponentially with half-lives of 2.77 and 3.45 h, respectively (P < 0.05). Results from these showed that blood and CSF compartments achieve equilibrium and indicated the feasibility of determining brain aluminum content using blood concentrations.


Stability of allylthiocyanate and allylisothiocyanate in bovine ruminal fluid. The rate of allylisothiocyanate (AITC) disappearance in bovine rumen fluid in vitro was 50-fold greater than the rate for allylthiocyanate (ATC). The results indicate that unlike AITC, ATC is more likely to be absorbed from the forestomachs and possible transferred to milk.


Glutathione and tissue amino acid responses to light-exposed parenteral nutrients. Effects of infusion of light-exposed (+L) or light-protected (-L) total parenteral nutrition solutions were investigated in rats. The parenteral infusions were carried out for 7 days through jugular cannulas in freely moving rats in metabolic cages. Plasma tyrosine and citrulline, hepatic methionine, valine, isoleucine, leucine and tyrosine, and biliary cystathionine were significantly greater in the -L than +L rats, whereas biliary arginine was significantly lower in the -L compared to +L rats. Bile flow, biliary inorganic phosphate and glucose were significantly lower, whereas biliary total glutathione (GSH+GSSG) was significantly greater in the -L compared to +L animals. These data suggest adverse effects on hepatobiliary function due to light exposure of parenteral nutrients. The endogenous markers used suggest that tight junction permeability, bile acid-independent flow, glutathione and amino acid homeostasis are altered by light exposure and that these changes can be minimized by light protection. The mechanisms involved in the induction of these changes need to be elucidated. The role of light exposure of parenteral nutrients during routine clinical use in the induction of hepatic dysfunction, a common metabolic complication of parenteral nutrition, needs to be considered.


Dietary restriction decreases thiobarbituric acid-reactive substances generation in the small intestine and in the liver of young rats. This study investigated the influence of dietary restriction on thiobarbituric acid-reactive substances (TBARS) contents and on the intracellular antioxidant defence system in the small intestine or liver of young rats. Four weeks of diet restriction (-40%) lowered the TBARS level in both organs. No variations were found for the superoxide dismutase and catalase activities; only liver seleno-dependent glutathione peroxidase was enhanced by the restriction. The protection appeared more marked in the intestine than in the liver, and would be dependent on glutathione concentration.


Clinical expression of organophosphate-induced delayed polyneuropathy in rats. Single doses of certain organophosphates (OP), such as dibutyl-2,2-dichlorovinyl phosphate (DBDCVP) cause organophosphate-induced delayed polyneuropathy (OPIDP) in hens. Clinical effects correlate with inhibition of neuropathy target esterase (NTE) which is considered the target for this toxicity. Pre-treatment with non-neuropathic NTE inhibitors, such as phenylmethanesulfonyl fluoride (PMSF), protects from OPIDP. However, when given after OPs, these compounds promote OPIDP. Chicks are relatively resistant to OPIDP despite high NTE inhibition. It has also always been reported that rats represent a species which is resistant to OPIDP and that they might develop morphological but not clinical signs of OPIDP. We report here that clinical OPIDP can be produced in 3.5- and 6-month-old rats by DBDCVP (5 mg/kg s.c.) and that it correlates with high (> 90%) NTE inhibition. When PMSF (120 mg/kg s.c. x 2) was given after DBDCVP, OPIDP was promoted. Pretreatment with PMSF protected from OPIDP. We conclude that resistance to OPIDP in the rat is age-related, as it is in the hen.


[The effect of different vacuum therapy regimens on protein and mineral metabolism in periodontal tissues]. Radionuclide label was used to study the effects of various vacuum therapy schemes on the protein and mineral metabolism in periodontal tissues. Vacuum therapy was found to normalize Ca, P, and protein metabolism in spontaneous atrophy of the alveolar processes in white rats. Focal dosed vacuum was found the most effective. These data will be used to develop a complex of measures to prevent atrophies of the maxillary alveolar processes.


[The morphological changes in the periodontal tissues of outbred white rats during ontogeny]. Morphologic studies, carried out by three methods, by van Gieson's, Schmorl's methods, and with the use of 0.1% solution of safranin T, have revealed heretofore unknown structures lying beyond the tooth rudiment of white noninbred rats and disappearing in the course of ontogenesis. The mechanism of the formation of autonomic circulation of the dental follicle, unrelated to the animal body, has been shown. Dental follicular tissues were found grown together with the gingival epithelium and they ruptured during tooth eruption.


[Alkaline and acid phosphatase activity in the dynamics of ectopic osteogenesis]. Activities of marker enzymes of osteoblasts (alkaline phosphatase), osteoclasts (tartrate-resistant isoform of acid phosphatase), and macrophages (tartrate-sensitive isoform of acid phosphatase) in bone tissue forming after osteoinduction on the basis of demineralized bone matrix were under study. Early (1 week) stages of osteosynthesis were characterized by low activity of alkaline phosphatase, acid phosphatase being represented by the tartrate-sensitive isoform. Two-three weeks later alkaline phosphatase activity grew and the tartrate-resistant isoform of acid phosphatase appeared. By the fourth-sixth weeks of osteogenesis alkaline phosphatase activity stabilized at a certain level and acid phosphatase activity still grew at the expense of the tartrate-resistant isoform. Conformity of the enzymologic data to changes in cellular populations in ectopic osteogenesis is discussed.


[A method for assessing the efficacy of means for interdental space hygiene]. A method for assessment of the efficacy of various means for maintenance of interdental space hygiene is suggested, based on measurement of the activity of acid producing oral microflora expressed through local pH-metry values. Three types of dental threads were under study.


[Lipid peroxidation and the status of the basal membrane of the acinar cells in the minor salivary glands of patients with Sjögren's syndrome]. Lipid peroxidation parameters were assessed from the levels of malonic dialdehyde, antioxidant activity from the blood and salivary total antioxidant activity, biopsy specimens of the minor salivary glands were examined by electron microscopy in 34 patients with Sjogren's disease. Both blood and salivary levels of malonic dialdehyde were found increased whereas total antioxidant activity lowered in these patients; destructive changes were detected in the acinar cells basal membranes. The authors suggest that spontaneous (because of insufficiency of antioxidant enzymic systems) lipid peroxidation reactions are responsible for these changes.


[The ATPase content of the blood neutrophils and lymphocytes in patients with chronic periodontitis]. Chronic periodontitis is associated with reduced immunologic reactivity of the body, that may present as disturbed status of the lymphocytes and neutrophils due to reduced activity of adenosine triphosphatases. Drug therapy of periodontitis, physiotherapy, oral hygiene, sodium chloride reducing diets are conductive to improvement of the clinical status of the periodontium and to recovery of ATPase activities.


[Changes in the electric conductivity of the dentin during caries treatment]. Dentin permeability at the bottom of carious cavities of 124 teeth was studied by electrometry. Dentin permeability was found to be higher in deep caries than in moderate-severe and higher in the teeth that had not been treated before than in those filled. Treatment of the cavities with potassium oxalate before filling helped rapidly and effectively lower the dentin permeability in order to prevent involvement of the pulp.


[The results of the hirudotherapy of patients with paresthesia of the oral mucosa]. Presents the immediate and late (a follow-up of up to 3 years) results of the treatment of 30 patients with oral mucosa paresthesia by the method of hirudotherapy. Discusses the factors influencing the treatment efficacy and leading to recurrences of the disease.