Haemodynamic changes and oxygen uptake during crossclamping of the thoracic aorta in dexmedetomidine pretreated dogs.

This study was designed to test the hypothesis that the alpha 2 adrenergic agonist, dexmedetomidine (DEX), decreases tissue oxygen demand thereby increasing tolerance to hypoxic insult. In 17 anaesthetized dogs, cardiac output was measured with thermodilution, blood flow through the inferior caval vein was determined using an electromagnetic flowmeter, and oxygen consumption was calculated by the Fick principle. The animals were divided into three groups: control group (n = 5), D3 and D30 groups (n = 6 for each group) treated with two doses of DEX (3 micrograms.kg-1 and 30 micrograms.kg-1, respectively) prior to aortic crossclamping. Upon crossclamping of the thoracic aorta, the cardiac index decreased in all three groups with the largest decrease in the D30 group, and the smallest decrease in the control group. Blood flow through the inferior vena cava decreased in all three groups of animals while blood flow through the superior caval vein increased in the control group, did not change in the D3 group, and decreased in the D30 group. Oxygen saturation in mixed venous blood increased in the control group, did not change in the D3 group and decreased in D30 group. Blood flow and oxygen uptake in the lower part of the body decreased in all groups. Oxygen consumption in the upper part of the body decreased equally in all three groups. Arterial lactate concentrations increased almost two-fold in the control group while it increased by only 30% in animals treated with DEX. A lesser increase in lactate concentrations and oxygen extraction in tissues below aortic crossclamping is consistent with the hypothesis that DEX decreases tissue oxygen requirement which might prove particularly useful in clinical situations where tissue hypoxia is expected.


Comparative in vitro cytotoxicity of taxol and Taxotere against cisplatin-sensitive and -resistant human ovarian carcinoma cell lines.

Using the sulforhodamine B assay, we compared the cytotoxic properties of the novel microtubule agent taxol and the semi-synthetic related compound Taxotere in nine human ovarian-carcinoma cell lines, including three pairs of cell lines rendered resistant to cisplatin or carboplatin. In addition, the cytotoxicity of the commonly used anticancer drugs cisplatin and adriamycin and the topoisomerase II inhibitor etoposide was determined. The results of continuous drug exposure showed that taxol [mean concentration producing 50% growth inhibition (IC50), 1.1 x 10(-9) M; range, 2.8 x 10(-9)-5 x 10(-10) M and Taxotere (mean IC50, 5.1 x 10(-10) M; range, 7.2-3.3 x 10(-10) M) were greater than 1,000 times more cytotoxic than either cisplatin (mean IC50, 3.1 x 10(-6) M; P less than 0.05) or etoposide (mean IC50, 2.3 x 10(-6) M; P less than 0.05) and greater than 100 times more cytotoxic than Adriamycin (mean IC50, 6.9 x 10(-8) M; P less than 0.05). Taxotere was more cytotoxic than taxol; following continuous exposure, the mean difference across the cell lines was 2 orders of magnitude (range, 1.1-3.9 orders of magnitude for individual lines). Although this difference did not reach statistical significance for any individual cell line (P values ranged from 0.17 for HX/62 to 0.9 for OVCAR-3), when all IC50 values for the 96-h experiments were pooled, Taxotere was found to be significantly more potent than taxol (P = 0.05). Following 2 h exposure, the mean cytotoxicity of Taxotere was 3.9-fold greater than that of taxol across the nine lines (range, 0.75- to 10-fold; P less than 0.05 for the CH1 cell line; overall pooled IC50 data, P = 0.05). Although a 71-fold range of sensitivity to cisplatin was observed across the six parent cell lines (IC50 most resistant line/IC50 most sensitive line), this was largely abolished by treatment with taxol (5.6-fold range) and Taxotere (2.2-fold range). Following continuous exposure of the three pairs of lines exhibiting acquired resistance to platinum, no cross-resistance with either Taxotere or taxol was found (resistance factors, less than 1.5). In the 41M and 41McisR pair of lines, in which previous studies have shown resistance to be due to reduced platinum accumulation, taxol and Taxotere exhibited some collateral sensitivity (resistance factors, 0.69 and 0.66, respectively). Taxotere and, particularly, taxol showed a pronounced concentration times exposure duration (C x T) dependence as compared with cisplatin (P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)


Measurement of neutrophil activation and epidermal cell toxicity by palytoxin and 12-O-tetradecanoylphorbol-13-acetate.

Palytoxin is a human and mouse skin irritant and complete mouse skin tumor promoter that differs from the well-studied phorbol ester class of tumor promoters in many respects. In this study, we have found palytoxin to stimulate the production of superoxide by isolated human neutrophils using electron paramagnetic resonance (EPR) spectroscopy with the spin-trap DMPO. This stimulation of oxyradical production by palytoxin is relatively weak, however, when compared to that by 12-O-tetradecanoylphorbol-13-acetate (TPA). The maximal amount of oxyradicals produced by palytoxin-stimulated neutrophils is 10(-4) mumols/10(6) neutrophils, and this stimulation requires nanomolar concentrations of palytoxin, with half maximal stimulation at concentrations of approximately 30 nM. In contrast, the tumor promoter TPA causes human neutrophils to generate in excess of 10(-3) mumols oxyradicals/10(6) neutrophils with concentrations as low as 1 nM. Toxicity to cultured human epidermal cells was observed at very low concentrations of palytoxin, with 50% loss of colony-forming efficiency observed at approximately 3 x 10(-13) M. For TPA, 50% loss of colony-forming efficiency for cultured epidermal cells requires approximately 5 nM. Thus, although palytoxin stimulates superoxide production in isolated neutrophils, epidermal cells are sensitive at much lower concentrations and are likely to be the important target cell in vivo. This is in contrast to TPA, where neutrophils are stimulated at concentrations less than those required to produce pathological effects on epidermal cells, suggesting that neutrophils may be an important target cell for TPA in vivo.


Inhibition of aflatoxin B1-induced gamma-glutamyltranspeptidase positive (GGT+) hepatic preneoplastic foci and tumors by low protein diets: evidence that altered GGT+ foci indicate neoplastic potential.

Previous studies in this laboratory with young Fischer 344 male rats have shown that the post-initiation development of aflatoxin B1 (AFB1)-induced gamma-glutamyltranspeptidase positive (GGT+) hepatic foci was markedly inhibited by low protein feeding, even though the energy intake was greater. This dietary effect, however, did not necessarily apply to hepatic tumor development. Thus, the present investigation was undertaken to examine this dietary effect upon the development of hepatic tumors and, is so doing, to determine the correlation of foci development with tumor development. Following AFB1 dosing (15 daily doses of 0.3 mg/kg each), animals were fed diets containing 6, 14 or 22% casein (5.2, 12.2, 19.1% protein) for 6, 12, 40, 58 and 100 weeks. Foci at 12 weeks and tumors at 40, 58 and 100 weeks developed dose-dependently to protein intake. Foci development, tumor incidence, tumor size and the number of tumors per animal were markedly reduced while the time to tumor emergence was increased with low protein feeding. Non-hepatic tumor incidence also was lower in the animals fed the lowest protein diet. Foci development indices (foci number, per cent liver volume occupied) were highly correlated with tumor incidence at 58 and 100 weeks (r = 0.90-1.00). Tumor and foci inhibition occurred in spite of the greater energy intake.


Mechanism of hind limb vasoconstriction due to cyclosporin A in the dog.

Cyclosporin A (CSA) causes an acute vasoconstriction of hind limb arterial vessels. To determine the mechanism of action of CSA on the peripheral arterial bed, studies were performed on the isolated femoral artery perfused at constant flow in 61 dogs. Changes in femoral perfusion pressure reflected variations in vascular resistance. Pure powder CSA was dissolved in autologous blood and injected at doses of 1, 5, 10, and 20 mg. Infusions of 1 and 5 mg CSA caused nonsignificant mean increases of 4 +/- 2 mm Hg (95% confidence interval [CI], 0-8; p > 0.05) and 10 +/- 4 mm Hg (95% CI, 0-21; p > 0.05) in femoral perfusion pressure, with CSA blood levels in the femoral vein averaging 40 +/- 16 and 126 +/- 50 nmol/l, respectively, at the end of the injections. Infusions of 10 and 20 mg CSA caused significant increases in femoral perfusion pressure averaging of 8 +/- 3 mm Hg (95% CI, 1-14; p < 0.05) and 20 +/- 4 mm Hg (95% CI, 11-29; p < 0.05) in femoral perfusion pressure. CSA blood levels at the end of injections averaged 271 +/- 99 and 431 +/- 146 nmol/l, respectively, in the femoral vein. Blockade of alpha-adrenergic receptors with phentolamine and surgical lumbar sympathectomy decreased significantly the CSA vasoconstrictive effect in peripheral arterial vessels, with increases in perfusion pressure averaging 29 +/- 5 mm Hg before and 14 +/- 3 mm Hg after phentolamine (p < 0.05) and 30 +/- 2 mm Hg before and 8 +/- 2 mm Hg after sympathectomy (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)


Active cell death in hormone-dependent tissues.

Active cell death (ACD) in hormone-dependent tissues such as the prostate and mammary gland is readily induced by hormone ablation and by treatment with anti-androgens or anti-estrogens, calcium channel agonists and TGF beta. These agents induce a variety of genes within the hormone-dependent epithelial cells including TRPM-2, transglutaminase, poly(ADP-ribose) polymerase, Hsp27 and several other unidentified genes. Not all epithelial cells in the glands are equally sensitive to the induction of ACD. In the prostate, the secretory epithelial cells that are sensitive to hormone ablation are localized in the distal region of the prostatic ducts, and are in direct contact with the neighboring stroma. In contrast, the epithelial cells in the proximal regions of the ducts are more resistant to hormone ablation, probably because the permissive effects of the stroma are attenuated by the presence of the basal epithelial cells, which are intercalated between the epithelium and stroma. The underlying biology of ACD in prostate and mammary glands, and its relevance to hormone resistance, is discussed in this review.


Mechanisms of alpha 1-adrenergic vascular desensitization in conscious dogs.

To investigate the mechanisms of alpha 1-adrenergic vascular desensitization, osmotic minipumps containing either saline (n = 9) or amidephrine mesylate (AMD) (n = 9), a selective alpha 1-adrenergic receptor agonist, were implanted subcutaneously in dogs with chronically implanted arterial and right atrial pressure catheters and aortic flow probes. After chronic alpha 1-adrenergic receptor stimulation, significant physiological desensitization to acute AMD challenges was observed, i.e., pressor and vasoconstrictor responses to the alpha 1-adrenergic agonist were significantly depressed (p < 0.01) compared with responses in the same dogs studied in the conscious state before pump implantation. However, physiological desensitization to acute challenges of the neurotransmitter norepinephrine (NE) (0.1 micrograms/kg per minute) in the presence of beta-adrenergic receptor blockade was not observed for either mean arterial pressure (MAP) (30 +/- 7 versus 28 +/- 5 mm Hg) or total peripheral resistance (TPR) (29.8 +/- 4.9 versus 28.9 +/- 7.3 mm Hg/l per minute). In the presence of beta-adrenergic receptor plus ganglionic blockade after AMD pump implantation, physiological desensitization to NE was unmasked since the control responses to NE (0.1 micrograms/kg per minute) before the AMD pumps were now greater (p < 0.01) than after chronic AMD administration for both MAP (66 +/- 5 versus 32 +/- 2 mm Hg) and TPR (42.6 +/- 10.3 versus 23.9 +/- 4.4 mm Hg/l per minute). In the presence of beta-adrenergic receptor, ganglionic, plus NE-uptake blockade after AMD pump implantation, desensitization was even more apparent, since NE (0.1 micrograms/kg per minute) induced even greater differences in MAP (33 +/- 5 versus 109 +/- 6 mm Hg) and TPR (28.1 +/- 1.8 versus 111.8 +/- 14.7 mm Hg/l per minute). The maximal force of contraction induced by NE in the presence or absence of endothelium was significantly decreased (p < 0.05) in vitro in mesenteric artery rings from AMD pump dogs compared with saline control dogs. Furthermore, alpha 1-adrenergic receptor density, as determined by [3H]prazosin binding in membrane preparations from vessels in the mesentery, was decreased (8.2 +/- 1.0 versus 18.4 +/- 1.4 fmol/mg protein, p < 0.001) without any change in Kd in the AMD pump dogs compared with the saline pump dogs.(ABSTRACT TRUNCATED AT 400 WORDS)


A study on the ecological habit of Armigeres subalbatus in Dawa area of the Mengshan Mountain in Shandong Province.

Armigeres subalbatus (A.s.) was reported in Shandong Province for the first time in 1965 and found in five counties of south Shandong including Pingyi, Linyi etc. in 1986. In Dawa area of the Mengshan mountain A.s. alults could be found in the first ten days of May, which increased in number in July, and become the dominant species in mosquito colonies in Aug. and Sept., then decreased gradually in number in Oct. and disappeared in Nov. There were two peaks of activity and blood-sucking behavior during the 24 hours of a day, one at dusk and the other at dawn. When the temperature dropped to 16 degrees C and below in the last ten days of Oct., the wigglers began their diapause period. The survival ratio reached 90.5% after 12 h freezing at -5 degrees C and none survived after 60 hours freezing. When the temperature rose to 17 degrees C and above the over-winterting larvae developed into adults, which could suck blood only at the temperature above 17.5 degrees C.


Role of alpha 2-adrenoceptors in normal and atherosclerotic human coronary circulation.

Experimental studies on the effects of alpha 2-adrenoceptors on regional coronary blood flow in normal and ischemic myocardium are highly controversial. A beneficial effect on regional ischemic myocardium has been demonstrated in different animal preparations with either alpha 2-adrenoceptor blockade or stimulation. Animal studies also demonstrated that postsynaptic alpha 2-adrenoceptors mediate vasoconstriction in coronary and femoral vascular beds. The aims of the study were 1) to investigate the effects of regional alpha 2-adrenoceptor stimulation on regional coronary blood flow in subjects with angiographically normal coronary arteries, 2) to assess the effect of alpha 2-adrenoceptor blockade on coronary circulation in control subjects, and 3) to examine the influence of atherosclerosis on coronary blood flow response to alpha 2-adrenoceptor blockade. The effect of regional administration of BHT 933 (a selective alpha 2-adrenoceptor agonist) was studied in eight subjects with angiographically normal coronary arteries. The coronary blood flow velocity was measured using a subselective intracoronary 3F Doppler catheter and coronary diameter by quantitative coronary angiography. BHT 933 induced a reduction in coronary artery diameter from 2.5 +/- 0.6 mm to 1.8 +/- 0.4 mm (p less than 0.05) as well as in coronary blood flow velocity (from 6.4 +/- 0.9 cm/sec to 4.6 +/- 1.9 cm/sec, p less than 0.01). In some subjects, ST segment abnormalities occurred. In patients with angiographically normal coronary arteries (n = 6), the regional infusion of a selective alpha 2-adrenoceptor blocking agent after beta-blockade did not change coronary diameter or coronary blood flow velocity. In contrast, in patients with significant coronary stenoses (n = 6), regional infusion of an alpha 2-adrenoceptor blocking agent reduced regional coronary artery diameter (from 2.3 +/- 0.5 mm to 2.1 +/- 0.6 mm, p less than 0.01) as well as coronary blood flow velocity (from 5.8 +/- 0.8 cm/sec to 3.7 +/- 0.6 cm/sec, p less than 0.05); in addition, alpha 2-adrenoceptor blockade significantly increased coronary sinus plasma norepinephrine levels (from 300 +/- 144 pg/ml to 429 +/- 207 pg/ml, p less than 0.01). The selective in vivo stimulation of alpha 2-adrenoceptors produces a reduction in coronary blood flow and diameter in humans with angiographically normal coronary arteries. alpha 2-Adrenergic blockade does not change coronary blood flow in subjects with angiographically normal coronary arteries (suggesting no resting alpha 2-adrenergic vasoconstrictor tone), whereas in patients with coronary artery stenosis, regional coronary blood flow decreases after alpha 2-receptor blockade. Finally, our data also suggest that alpha 2-adrenoceptors participate in the modulation of sympathetic neuronal norepinephrine release in the human heart.


[Influence of moxibustion on TXA2 and PGI2 in plasma of rat infected epidemic hemorrhagic fever virus (EHFV)].

In this paper, the model of rat infected EHFV was made and the influence of moxibustion on TXA2 and PGI2 in its plasma was observed. The results show that the content of TXA2 increased and PGI2 decreased in rat significantly after the abdominal inoculation of EHFV, and the content of TXA2 decreased and PGI2 increased markedly in rat infected EHFV to normal level after treatment with moxibustion, suggesting that the regulative function of moxibustion on TXA2 and PGI2 is one of its nerve-endocrine-immune regulations to the body, and there is an important significance. This study provides an important reference for mechanism exploration of moxibustion preventing and treating EHF.


Early postnatal changes in presynaptic potassium sensitivity.

Amplitude histograms of miniature endplate potentials (MEPPs) and the overall frequency of skew-MEPPs and bell-MEPPs were examined in 5 and 15 mM potassium solutions at postnatal day (PD) 3, PD 10 and PD 27 neuromuscular junctions. Temporal non-uniformities in spontaneous release produced clusters of bell-MEPPs at PD 0-PD 3 junctions. PD 3 nerve terminals that preferentially released skew-MEPPs (5 mM potassium) were significantly (P less than 0.01) less sensitive to elevations in potassium than more mature (PD 10) junctions that preferentially released bell-MEPPs. Increases in the potassium concentration at PD 3 junctions increased the frequency of bell-MEPPs and altered the MEPP amplitude distribution profile by significantly (P less than 0.01) reducing the percentage of skew-MEPPs. Although the potassium sensitivity of PD 10 and PD 27 preparations were as expected for adult preparations, there was an increase in overall MEPP frequency in 5 mM potassium between PD 10 and PD 27. These results suggest that early postnatal increases in the number of presynaptic calcium channels establish adult levels of depolarization sensitivity and promote the preferential spontaneous release of bell-MEPPs. Since these changes occur during an early period of synapse elimination, they may play a critical role in synapse stabilization.


Cortical AMPA receptors: age-dependent regulation by cellular depolarization and agonist stimulation.

We have recently shown that a high-affinity AMPA receptor labelled with the antagonist [3H]CNQX can be regulated in a 'living' cortical slice preparation by agonist stimulation or changes in electrical activity (Lanius, R.A. and Shaw, C. (1992) Anat. Rec., in press). Based on a study of GABAA receptors (Shaw, C. and Scarth, B.A. (1992) Mol. Brain Res., in press), which showed age-dependent changes in regulation, we have now investigated the regulation of high-affinity AMPA receptors in neocortex at different stages in postnatal development. The results show that regulation by agonist stimulation and increases in bioelectric activity are age-dependent in amount and, in the latter case, in direction. Agonist stimulation using quisqualate resulted in a significant receptor down-regulation of approximately 7% at ages less than 20 days postnatal; in adult rats quisqualate led to a significant 23% decrease. Changes in bioelectric activity induced by a combination of veratridine and glutamate showed a significant increase in AMPA receptor number of 16% at ages less than 20 days, whereas such treatment resulted in a significant 18% decrease in adult rats. The present data reveal a near mirror-image to the effects of veratridine and glutamate and agonist on GABAA receptors in the same preparation, but with a temporal mismatch in the amount and direction of regulation. We speculate that the age-dependent differences in direction of regulation for the receptor populations which serve key excitatory and inhibitory functions in cortex may provide a molecular basis for the gradual decline of neuronal plasticity during the critical period.


An immunohistochemical study of regenerating newt retinas.

Light-microscopical examination was carried out to investigate the emergence and development of several classes of immunoreactive cells in regenerating retinas of the adult newt (Triturus pyrrhogaster) after total retinal ablation. Immunoreactive proliferating cell nuclear antigen (ir-PCNA, a marker for replicating cells) was present in nuclei of all neuroblasts in the early mono-layered to several-layered stages (15-20 days after retinal ablation; days 15-20), but was lost progressively in an intermediate-to-central/peripheral order as cells and layers increased (days 20-25). Cells, which had lost ir-PCNA, began to separate to form the outer nuclear, inner nuclear and ganglion cell layers around days 25-30 (the cell separation stage). Finally, the location of ir-PCNA was restricted to a band of neuroblast cells at the retinal margin (days 30-35) as seen in intact adult retinas. Visinin-immunoreactive (ir) cells, mainly destined to be cones, appeared first singly or as clusters at the most distal layer in the intermediate region of retinas multi-layered with PCNA-ir neuroblasts, which was followed by appearance of opsin-ir rod outer segments and tyrosine hydroxylase-ir amacrine cells around the cell separation stage. Shortly later, cells respectively immunoreactive to glutamic acid decarboxylase, neuropeptide Y, serotonin, glucagon, glutamine synthetase, glial fibrillary acidic protein, substance P and protein kinase C were found to emerge also in an intermediate-to-central/peripheral sequence. Some of the glucagon-ir cells appeared to be of an interplexiform type.


A simple, sensitive technique for classification of apolipoprotein(a) isoforms by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Lipoprotein(a) (Lp(a)) is a lipoprotein containing a unique glycoprotein, apolipoprotein(a) (apo(a)), which shows considerable heterogeneity of apparent molecular mass on sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). A unifying classification of isoform has been lacking. A simple sensitive procedure for classifying apo(a) isoforms was developed in which the relative mobility of apo(a) on SDS-PAGE was related to that of apolipoprotein (apo) B-100 (Rf vs B). After Western blotting apo(a) bands were visualised by a sensitive double antibody technique employing commercial polyclonal antibodies (sheep antihuman Lp(a) antibody, alkaline phosphatase-linked donkey antisheep antibody). The technique was sensitive (lower limit of detection 0.02 micrograms apo(a)) and had good reproducibility (coefficient of variation 0.9-6.4%). Ten isoform mobilities are described (less than 0.35, 0.40, 0.50, 0.60, 0.70, 0.80, 1.0, 1.10, greater than 1.15). Individuals may have single or double band phenotypes. This classification is compatible with those previously described and the method is suitable for many laboratories, as it employs standard equipment and commercially available materials.


Characterization of the carbohydrate moiety of human gamma-glutamyltransferases using lectin-blotting and glycosidase treatment.

The presence of both N- and O-linked carbohydrate was demonstrated on gamma-glutamyltransferase (GT) from human liver and kidney. The N-linked carbohydrate constituted 25-30% of the total molecular mass of the enzymes. O-Glycosylation was detected on both subunits of the liver enzyme, but only on the small subunit of the kidney enzyme. Lectin blot analysis indicated that the glycan chains were of the complex type for both the liver and the kidney GT and lectin blotting may to some extent distinguish the two enzymes.


HLA class II gene polymorphism contributes little to Hashimoto's thyroiditis.

Previous studies of HLA and Hashimoto's thyroiditis have shown weak associations between the disease and various HLA-DR antigens. To define better the contribution of HLA class II alleles to susceptibility to Hashimoto's thyroiditis. Comparison of HLA-DRB, DQA and DQB restriction fragment length polymorphisms in patients with Hashimoto's thyroiditis and control subjects, and meta-analysis of this and other published studies. Fifty Caucasian patients with Hashimoto's thyroiditis and 93 racially-matched control subjects. A 4.6 kb Taq 1 DQA restriction fragment length polymorphism occurred in 60% of patients compared with 35.5% of controls, Pc < 0.025. No other restriction fragment length polymorphism was significantly associated with the disease. Meta-analysis of several studies demonstrated weak, positive associations between the disease and DR3 and DR4. An association with DR5 was not significant. DR antigens are unlikely to determine disease susceptibility directly. These findings indicate that any contribution of HLA genes to inherited susceptibility to Hashimoto's thyroiditis is small and requires confirmation in family studies.


A case of multiple endocrine neoplasia: hyperparathyroidism, insulinoma, GRF-oma, hypercalcitoninaemia and intractable peptic ulceration.

A 42-year-old woman with a family history of multiple endocrine neoplasia type 1 (MEN 1) presented with symptomatic hypoglycaemia and peptic ulceration. Investigation revealed an insulinoma, hyperparathyroidism, hypercalcitoninaemia with a positive pentagastrin stimulation test, acromegaly due to a GRF-oma, hyperprolactinaemia and normal serum gastrin levels. Five pancreatic tumours were removed at laparotomy and immunostaining was positive for insulin, calcitonin, somatostatin and glucagon. Post-operatively she developed elevated serum gastrin levels and gross peptic ulceration, despite H2-blockers, and died of gastro-intestinal haemorrhage suggesting that removal of the somatostatinoma may have allowed increased gastrin secretion from a gastrinoma. This case emphasizes the importance of measuring a wide variety of tumour marker peptides in MEN 1 and suggests that caution is required in interpretation of the pentagastrin stimulation test in such cases. Patients with MEN 1 and known peptic ulceration may require perioperative omeprazole treatment even if serum gastrin levels are normal.


Effects of alpha 1-receptor blockade on the hemodynamic responses to exercise in young hypertensives.

The purpose of this study was to determine if alpha 1-adrenergic receptor blockade alters the hemodynamic response to exercise in young (less than 25 yr) male borderline hypertensives differently than in young normotensives. Five hypertensive (HTN, MAP greater than 105 mmHg) and 7 normotensive (NTN, MAP less than 95 mmHg) college-age males underwent two 30 min bouts of cycle ergometry exercise at 50% VO2pk in a warm (25 degrees C, 50% rh) environment; one following alpha 1-receptor blockade with prazosin (PRAZ) and the other following placebo administration (PLAC). During resting PLAC and compared to NTN, HTN exhibited an elevated cardiac index (CI, p = .002), similar HR and elevated total peripheral resistance index (TPRI, p = .015). During resting PRAZ, CI and TPRI were similar but HR was higher (p = .013) in HTN than NTN. While reduced during PRAZ, resting MAP was higher in HTN than NTN (p = .007) for both trials. With exercise and PLAC, CI was higher (p = .029) while HR and TPRI were similar for HTN compared to NTN. With PRAZ, the exercise CI, TPRI and HR responses were similar for both groups. Exercise MAP was blunted in both groups with PRAZ. While not differing significantly between groups for each treatment, MAP was stable for NTN while it declined after 10 min of exercise in HTN. The elevated CI seen in exercising HTN with PLAC was removed with PRAZ; the exercise response was otherwise unaltered by alpha 1-blockade. Consequently, these data suggest that young male hypertensives have an elevated blood pressure due to an elevated CI incompletely offset by a reduced TPRI. While alpha 1-blockade lowers MAP by lowering CI, the MAP response to exercise remains unaltered.


Pseudohypoparathyroidism type I and Albright's hereditary osteodystrophy with a proximal 15q chromosomal deletion in mother and daughter.

A 33-year-old woman and her 71-year-old mother were both found to have pseudohypoparathyroidism type I with Albright's hereditary osteodystrophy associated with a cytogenetic deletion of the proximal part of one chromosome 15, resembling that found in Prader-Willi syndrome. As there are overlapping clinical features between these two syndromes a causal relationship cannot be excluded. However, molecular analyses with 10 probes from this region did not detect any uniparental disomy or deletion, features frequently found in Prader-Willi syndrome.


Anti-endothelial cell antibodies in nephropathia epidemica and other viral diseases.

Increased capillary permeability is a central feature of the severe forms of haemorrhagic fever with renal syndrome (HFRS) and occurs also, though less frequently, in nephropathia epidemica (NE), one of the milder forms of this syndrome, caused by Puumala virus. We therefore searched for antiendothelial cell antibodies (AECA) in patients with NE and in those with other presumed or serologically proven acute viral illnesses. By enzyme immunoassay, using human umbilical vein endothelial cells (HUVEC) as the substrate, IgG class AECA were detected significantly more frequently in patients with NE and with influenza A than in Red Cross blood donors. A lesser degree of reactivity could be shown with a human alveolar cell carcinoma line and with human and mouse embryonic fibroblasts. Pretreatment of HUVEC with interferon-gamma (IFN-gamma), but not with IL-1 or tumour necrosis factor-alpha (TNF-alpha), increased their ability to bind IgG of sera from patients with NE and acute febrile illnesses. We conclude that, although AECA can be demonstrated in NE, they occur also in other acute viral illnesses and, unless cytopathic by a mechanism not shared by the AECA of these other illnesses, are unlikely to be casually related to the capillary leak in HFRS.


Characterization of cytokine gene expression in CD4+ and CD8+ T cells after activation with phorbol myristate acetate and phytohaemagglutinin.

Cytokines are important mediators involved in the development of effector cells and in the regulation of immune responses. The gene expression of these mediators in T cell subset has yet to be fully elucidated. Using sensitive reverse transcription-polymerase chain reaction (RT-PCR), the kinetics of cytokine gene expression in human CD4+ and CD8+ T cells were examined. CD4+ T cells were more readily activated by phorbol myristate acetate (PMA) and phytohaemagglutinin (PHA) than CD8+ T cells in terms of the IL-2 receptor (IL-2R) mRNA expression. Quantitative differences in cytokine gene expression between CD4+ and CD8+ T cells were confirmed and higher levels of cytokine mRNAs were induced in CD4+ than in CD8+ T cells. Early induction of IL-2 mRNA was observed in both T cell subsets. The demonstration of different kinetics of cytokine gene expression illustrates one of the examples of the complexity of immunoregulation. The differential response of cytokine gene expression in different T cell subsets should be taken into consideration when clinical studies in cytokine production by peripheral blood mononuclear cells are interpreted.


Increased CD11/CD18 expression on peripheral blood leucocytes of patients with sarcoidosis.

Sarcoidosis is a multisystem disease of unknown etiology characterized by non-caseating granulomata, formed mainly from macrophages surrounded by lymphocytes and plasma cells. Using a novel method for the preparation of blood leucocytes for flow cytometry, we report increased expression of LeuCAMs (CD11/CD18) on peripheral blood leucocytes of 11 Caucasian and 10 Afro-Caribbean patients with sarcoidosis compared with age-, sex- and race-matched controls. Whilst the percentages of the cells expressing CD11/CD18 were no different, the density, expressed as mean fluorescence intensity (MFI), was greater for all leucocytes in sarcoids than in normal individuals. The expression of intercellular adhesion molecule-1 (ICAM-1), a ligand for LFA-1 which is expressed on all leucocytes, was not significantly different from normal, whereas HLA-DR was expressed more intensely on sarcoid monocytes (P less than 0.01) and blood lymphocytes (P less than 0.005) than control cells. Our findings are consistent with leucocyte activation although we were unable to confirm reports of elevated tumour necrosis factor-alpha (TNF-alpha) in the patients' plasma using an ELISA. Increased expression of adhesion molecules on peripheral blood leucocytes may play a role in the cellular extravasation, aggregation, and granuloma formation seen in sarcoidosis.


A study of serum prolactin levels in schizophrenia: comparison of males and females.

1. Serum prolactin levels were measured in large cohorts of schizophrenic patients (67 males and 42 females) and normal subjects (78 males and 42 females). 2. There was no significant differences between the serum prolactin levels of patients and controls, except in the age group 15-29 years. There were no significant differences between the serum prolactin levels of males and females, either among the patients or the control subjects. 3. The rise in serum prolactin levels after the commencement of neuroleptic medication in the patients was greater in females than in males even though the female patients received neuroleptics at lower doses. 4. These data indicate that serum prolactin levels in unmedicated males and females are similar; however, the prolactin response to neuroleptic medication is greater in females than in males.


Human immunodeficiency virus-infected monocyte-derived macrophages express surface gp120 and fuse with CD4 lymphoid cells in vitro: a possible mechanism of T lymphocyte depletion in vivo.

Monocyte-derived macrophages (MDM) infected in vitro with a macrophage-tropic strain of human immunodeficiency virus (HIV) fused with uninfected, CD4-expressing T lymphoblastoid cells, but not with a subclone of these cells lacking surface CD4. Infected MDM also fused with uninfected autologous and heterologous MDM. Recombinant soluble CD4 protein (rsCD4) (10 micrograms/ml) and full-length recombinant glycosylated gp120 (20 micrograms/ml) each inhibited fusion by 94-99%; the inhibition was dose-dependent. The N-terminal portion of gp120 did not inhibit syncytium formation. Fusion was also inhibited by a monoclonal antibody to an epitope which binds gp120 (S3.5), but not by antibody to an epitope not involved in gp120 binding (OKT4). HIV-infected MDM specifically bound fluorescein-conjugated rsCD4, and virus could be visualized budding from the surface of these cells. HIV-infected MDM express viral gp120 on their surface and fuse with CD4-bearing cells in a fashion similar to lymphoid cells. Macrophages may contribute to CD4 lymphocyte depletion in vivo by this fusion mechanism.


The onset of nephritis in the (NZB x SWR)F1 murine model for systemic lupus erythematosus correlates with an increase in the ratio of CD4 to CD8 T lymphocytes specific for the nephritogenic idiotype (IdLNF1).

An idiotypically related family of nephritogenic antibodies (IdLNF1) has been shown to be important in the pathogenesis of autoimmune glomerulonephritis in the (NZB x SWR)F1 hybrid, SNF1. Idiotype-specific T lymphocytes which modulate expression of antibody bearing that idiotype may be important in the pathogenesis of systemic lupus erythematosus (SLE). Here, IdLNF1-reactive T lymphocytes were not only found to be present in the NZB, SWR, and SNF1, but a significantly (P < or = 0.05) greater number of IdLNF1-reactive Thy 1.2+ splenic lymphocytes were observed as early as 12 weeks of age in the SNF1. Further, a significant shift in the ratio of CD4+ to CD8+ IdLNF1-reactive T lymphocytes in favor of CD4+ IdLNF1-reactive T cells was observed at 20 to 24 weeks of age only in the SNF1. This shift correlated with an increase in IdLNF1+IgG, and deposition of IdLNF1 bearing immunoglobulin in the kidney glomeruli. These observations suggest a role for idiotype-specific T lymphocytes in the induction of glomerulonephritis in this murine model of SLE.


Hormonal and immunological regulation of 2', 5'-oligoadenylate synthetase activity in human peripheral blood mononuclear cells.

A newly developed method for assaying 2', 5'-oligoadenylate (2, 5A) synthetase activity by polyacrylamide gel electrophoresis was applied to peripheral blood mononuclear cells (PBMC) from normal subjects, HIV-positive subjects, and renal cell carcinoma (RCC) patients. Sex differences were observed in 2, 5A synthetase activity of PBMC from normal young adults, males having eightfold higher activities of this enzyme than females. Moreover, compared to values for postmenopausal (PM) females receiving estrogen replacement, untreated PM females had higher activities. Collectively, these results suggest that estrogen downregulates 2, 5A synthetase activity. Activities of 2, 5A synthetase were investigated in two disease states associated with altered immune function. In one patient with AIDS-related Kaposi's sarcoma, interferon-alpha (IFN-alpha) therapy increased 2, 5A synthetase activity twofold. In addition, combined therapy with interleukin-2 (IL-2) and IFN-alpha increased 2, 5A synthetase activities in eight of nine patients with RCC. Therefore, in patients receiving immunotherapy with IL-2 and IFN-alpha, our new assay could contribute to evaluation of immune stimulation. In general, studies in vitro confirmed these observations; however, exposure of PBMC from RCC patients revealed that in vitro IL-2 failed to induce this enzyme activity as it did in PBMC from normal volunteers.


Effective treatment of hypertension in patients with diabetes mellitus.

Atherosclerosis, presenting as macrovascular complications of diabetes mellitus, produces approximately 80% of all diabetic mortality, whether the patient has Type I insulin-dependent diabetes (IDDM) or Type II non-insulin dependent diabetes mellitus (NIDDM). Specifically, 75% of this atherosclerotic macrovascular mortality flows as the outcome of coronary atherosclerosis, which is increased approximately two-fold in men and four-fold in women with diabetes as compared with otherwise matched populations with entirely normal carbohydrate tolerance. The remaining 25% of this atherosclerotic mortality in patients with diabetes mellitus is the result either of accelerated cerebrovascular or of peripheral vascular complications of diabetes, both of which are increased four-fold and five-fold, respectively, in patients with diabetes mellitus, regardless of type. Furthermore, atherosclerosis is the principal cause of hospitalizations for patients with diabetes mellitus. Admissions for this complication account for approximately 77% of total hospitalizations for diabetes owing to complications. Aside from mortality data alone, atherosclerosis is obviously a leading cause of diabetic disability, since it produces patients who are chronic cardiovascular, peripheral or cerebrovascular cripples, perhaps for many years before their ultimate demise. Small blood vessel or microvascular complications of diabetes mellitus, while formerly thought to be the end-stage in the unfolding of the diabetic process, do not appear to have the potential for mortality as do the atherosclerotic large blood vessel complications.(ABSTRACT TRUNCATED AT 250 WORDS)


The use of beta-blockade therapy in treatment of congestive heart failure.

If the activation of the sympathetic nervous system in chronic heart failure is causally related to progressive pump dysfunction, sudden death, and exercise intolerance, then selective blockade of the beta-adrenergic system may prove to be therapeutically beneficial. This report briefly reviews the evidence that there is systemic activation of the sympathetic nervous system in chronic heart failure, postulates mechanisms by which this activation might contribute to the morbidity and mortality of the syndrome, and hypothesizes further regarding how beta blockade may be beneficial in heart failure. The clinical evidence that the use of beta blockers is beneficial in the treatment of chronic heart failure is reviewed.


The effect of age and acetylator phenotype on the pharmacokinetics of sulfasalazine in patients with rheumatoid arthritis.

The pharmacokinetic disposition of sulfasalazine and its metabolites was studied in 8 young and 12 elderly patients with active rheumatoid arthritis. Equal numbers of slow and fast acetylators were included in each age group. Patients received enteric-coated sulfasalazine 2g daily for 21 days; specimens of serum and urine were collected for 96 h after administration on days 1 and 21. The elimination half-life of sulfasalazine was greater in the elderly patients. Many disposition parameters of sulfapyridine differed in slow and fast acetylators; of greatest significance were the increased values of steady-state serum concentration in the slow acetylators. There was no effect of age on any sulfapyridine disposition parameters. Values for the steady-state serum concentrations of N-acetyl-5-acetylsalicylic acid were greater in elderly than in young patients. The metabolism of sulfapyridine was markedly affected by acetylator phenotype and this was reflected in the composition of sulfapyridine-related material in the urine. Thus, age is a determinant of the steady-state concentrations of salicylate moieties but acetylator phenotype plays a greater role in determining the serum concentration of sulfapyridine, which has greater therapeutic implications in rheumatology.


Expression of adhesion molecules on circulating leucocytes in patients with inflammatory bowel disease.

1. The expression of leucocyte antigens CD11/CD18 and complement receptor 1 was studied on the circulating leucocytes of 13 patients with inflammatory bowel disease and 13 age- and sex-matched healthy control subjects. 2. Monoclonal antibodies against CD11/CD18 and complement receptor 1 were added to leucocyte suspensions from patients and control subjects. Antibody binding was detected using a fluorescein-conjugated rabbit anti-mouse antibody and flow cytometry. The proportions of lymphocytes, monocytes and granulocytes expressing these molecules and the density of antigen expression, measured as mean fluorescence intensity, were determined. 3. There were no differences between patients and control subjects in the mean fluorescence intensity of antibody staining of surface molecules or in the proportion of cells expressing each molecule for any cell type. Analysis of subgroups of patients according to disease type, severity or treatment also showed no difference compared with control subjects. 4. We conclude that failure to identify a population of circulating leucocytes whose adhesion molecules or complement receptors are upregulated may arise because cells are only activated locally within the gut vasculature. Alternatively, structural changes in these molecules, rather than an increase in their number or the expression of other surface glycoproteins, may be more important in mediating adhesive interactions in inflammatory bowel disease.


[Micropolyarteritis. The modern nosographic picture and a discussion of a clinical case].

Having observed a patient presenting micropolyarteritis with necrotic skin lesions, hypertension and renal injury, the authors had the opportunity to define more closely a disease that only recently has been recognized as a separate nosological entity within the vast and as yet not fully understood field of arterial disorders. In addition, recent literature on the subject is critically reviewed.


Immunological follow-up of 17 patients with rheumatoid arthritis treated in vivo with an anti-T CD4+ monoclonal antibody (B-F5)

Seventeen patients with steroid-refractory rheumatoid arthritis were treated with a monoclonal antibody: anti-T CD4/B-F5 (IgG1) for 10 days. The daily dose was 20 mg. No severe side effects were observed and clinical improvement was seen in 15 patients, accompanied by a steep decline in C reactive protein levels. This improvement persisted as long as 12 months in 3 patients. A decline in lymphocyte counts was observed 2 hours after infusion. CD3+, CD4+, CD8+ and B cells were affected. Monocyte levels also decreased, whereas NK cell levels remained unchanged. After 24 hours a subsequent recovery of lymphocyte cell numbers made it possible to return to pre-treatment levels. Residual CD4+ cells coated with CD4 antibody were sporadically found even if residual antibody could be detected in the serum. These results indicate insufficient mAb concentrations. No patients developed detectable anti-mouse Ig antibodies during the treatment period, but 5 patients developed antibodies 15 to 30 days after the end of the treatment. Proliferative responses (mainly the response to ConA) were reduced at the end of the treatment. One month later the proliferative response returned to pre-treatment levels. mAb treatment did not induce long lasting cell activation, as indicated by the low levels of CD25+ or DR+ cells. Soluble IL2 receptor levels were significantly higher before treatment, but did not change after treatment. Soluble CD8 and soluble CD4 molecules were also more numerous before treatment and this increase was correlated with clinical parameters. Of interest was the correlation between the variations in soluble CD8 and the Ritchie index during treatment. The increased levels of serum TNF alpha and IL6 were not modified by treatment. A randomized study now appears necessary to prove the efficacy of the treatment. Such a study would also provide biological data and thus help to define factors predictive of a response in this heterogeneous disease.


Dipeptidyl peptidase IV in patients with systemic lupus erythematosus.

The activity of dipeptidyl peptidase IV (DPP IV) was measured in the serum and peripheral blood mononuclear cells (MNC) of patients with systemic lupus erythematosus (SLE). The number of DPP IV positive (DPP IV+) lymphocytes in blood smears was determined cytochemically in groups of patients with active, moderate and inactive disease. Compared with healthy subjects, serum DPP IV activity was significantly decreased regardless of the level of disease activity. DPP IV activity in MNC was markedly decreased only in the patients with the active disease. Moreover, marked differences in the number of DPP IV+ lymphocytes could be detected between the groups of patients with the inactive and/or moderately active forms of the disease and those with active disease. The percentages of DPP IV+ lymphocytes, as well as DPP IV activity in MNC, showed significant correlations with the percentages of E-rosetting cells. Evaluation of DPP IV in SLE patients represents a new approach in the study of the pathological process of this disease.


Regulation of in vitro anti-DNA antibody production by a novel disease modifying anti-rheumatic drug, Lobenzarit.

Lobenzarit (CCA) is a novel disease modifying anti-rheumatic drug. Although CCA has been shown to prevent the development of the autoimmune disorders in NZB/W F1 mice and in MRL/l mice, the precise mechanism of its action has not yet been clarified. The current study examined the effect of CCA on the in vitro production of anti-DNA antibody, a hallmark of the autoimmune disorders. In vitro anti-DNA antibody production was induced from highly purified B cells of normal human individuals by stimulation with Staphylococcus aureus and CD4+ T cells or with immobilized anti-CD3 activated CD4+ T cells. CCA suppressed the production of anti-DNA antibody as well as IgM at pharmacologically obtainable concentrations (10-50 micrograms/ml). CCA did not inhibit the initial stages of B cell activation in either culture system, but rather suppressed the maturation of previously activated B cells. Although CCA suppressed IL2 production by immobilized anti-CD3 activated CD4+ T cells, its suppressive effects on B cells were not overcome by the addition of IL2 or factors generated from mitogen activated T cells (TF). CCA did not suppress IL6 production by immobilized anti-CD3 activated CD4+ T cells nor that by B cells activated with SA+ IL2. These results indicate that CCA suppresses the production of anti-DNA antibody by directly inhibiting activated B cells. The data therefore suggest the possible efficacy of CCA in suppressing the function of activated B cells in human SLE patients.


Development of a new investment for high-frequency induction soldering.

This study developed a new investment for induction soldering using high frequency induction heating. Ninety-five mass% magnesia clinker and 5 mass% dental stone were selected for the main constituents. The magnesia investment itself was scarcely affected by induction heating, so the addition of metal powders such as Fe, Ni, Co were investigated. Among these three powders, the addition of 10 mass% cobalt powder was most effective. This investment needed only 40 seconds of high frequency induction heating to go from room temperature to 900 degrees C without preheating. Thermal expansion of this investment in a vacuum atmosphere was 1.25% at 1000 degrees C. Dimensional changes during induction soldering were measured using German-silver and silver solder. When the new magnesia investment containing 10 mass% Co powder was used, the dimensional change was -0.2%. This contraction was less than when a magnesia investment without metal additives was used.


The ontogeny of homeothermic regulation in post-hatching chicks: its influence on the development of hearing.

1. The maturation of homeothermy in chicks from day 0 to day 30 after hatching (P0-P30) was studied by measuring rectal temperatures following different environmental exposures. 2. Body temperature regulation and an adult-like temperature (41.5 degrees C) develop with different time courses, being mature on days P4 and P23, respectively. After 1 hr at 20 degrees C, P0 chicks were 4.5-6.5 degrees C cooler than P30 animals. 3. A temperature effect shifts frequency in the auditory pathway up to 0.5 octaves to lower values. Some shifts in tonotopic maps observed in developmental studies of frequency representation in awake chicks can be fully explained by this temperature effect.


Synaptic transmission at high pressure: effects of [Ca2+]o.

1. The effects of pressure on synaptic currents were examined in crayfish abdominal muscles. 2. Helium pressure (10.1 MPa) considerably decreased extracellularly-recorded excitatory junctional potentials associated with increased short-term facilitation. 3. These effects could be mimicked by a reduction of [Ca2+]o, and partially compensated by an increase in [Ca2+]o. 4. Pressure also reduced the amplitude of the extracellular nerve terminal potentials (ENTP) by up to 25%, and significantly increased synaptic delay in a [Ca2+]o-dependent manner. 5. The interaction between compression and various [Ca2+]o were analysed in terms of an existing model of transmitter release. The results were consistent with the hypothesis that high pressure decreases the maximal Ca2+ influx into nerve terminals. 6. The decreased ENTP and increased synaptic delay suggest that additional processes may be involved in pressure effects on synaptic transmission.


Effects of angiotensin II and bladder condition on hydration behavior and water uptake in the toad, Bufo woodhousei.

1. Water absorption response (WR) behavior and water weight gain were examined in hydrated toads, Bufo woodhousei, treated with angiotensin II (AII) or with a control Ringer's solution. The effects of urinary bladder condition (ad lib. bladder urine or empty bladder) were examined concurrently. 2. Toads treated with AII (100 micrograms/100 g body weight), spent more time in WR posture and absorbed more water than Ringer's-injected toads. 3. Toads with empty bladders maintained WR posture for longer periods of time and gained more weight than toads whose bladders were not emptied. 4. The effects of AII and bladder urine on water absorption by B. woodhousei appear to be separate and additive.


Ontogeny of type I and type III deiodinase activities in embryonic and posthatch chicks: relationship with changes in plasma triiodothyronine and growth hormone levels.

1. The ontogeny of type I and type III deiodinase activities was studied in embryonic and posthatch chicks. 2. Hepatic type I activity showed a 3-fold increase up to the period of pipping and hatching and decreased slowly thereafter. 3. Hepatic type III activity increased by 3-fold from E14 to E17 and decreased more than 10-fold from E17 to C0. Posthatch levels were very low. 4. Type I activity in the kidney decreased slowly after hatching while type III activity was very low over the whole period studied. 5. Developmental changes during the late embryonic period suggest a causal relationship between the increase in plasma GH and T3 levels and the decrease in hepatic type III activity.


Sympathoadrenal activity during helox-cold induced hypothermia in Syrian hamsters.

1. As reflected by increasing plasma concentrations of cortisol, norepinephrine, epinephrine and dopamine, a marked stimulation of the adrenal cortex and of the sympathetic nervous system occurred in Syrian hamsters during moderate hypothermia induced by helium-oxygen atmosphere and cold. 2. A profound hyperglycemia was observed during hypothermia. 3. All effects due to the helium-oxygen atmosphere and cold exposure (helox-cold) disappeared almost completely after rewarming. 4. The results corroborate the hypothesis of an involvement of the adrenal cortex combined with the sympathetic nervous system in the control of acute induced heat production.


Secretory oedema in diabetic submandibular glands during parasympathetic nerve stimulation: relationship to microvascular abnormalities in streptozotocin-treated rats.

1. Submandibular secretion during parasympathetic stimulation (5 Hz) was examined in streptozotocin-diabetic and age-matched control rats. 2. At 3 weeks, but not 3 and 6 months, flow rate was initially greater than in controls, but it declined rapidly after 30 min. 3. The reduction in flow rate was associated with oedema of the gland. 4. At 3 months, graded stimulation revealed a tendency to oedema at frequencies of 10 Hz and above. 5. Morphologically, submandibular capillary density was increased in diabetic rats. 6. Thus, in diabetes the submandibular gland appears less able to withstand continuous parasympathetic stimulation, due in part to an increase in tissue capillary area.


Preparation and execution of movement: parallels between insect and mammalian motor systems.

1. The organization of the motor systems underlying locomotion in insects and mammals is surprisingly similar. There are also parallels between the insect motor system and the system underlying reaching and the occulomotor system in primates. 2. The movements generated by all these systems are planned or prepared before their execution and there is a partial separation of circuits for preparation and execution. 3. These circuits consist of multiple descending pathways interconnected to form overlapping loops which work co-operatively to determine the motor output. Thus, both insect and mammalian motor systems can be treated as parallel distributed (PDP) systems. 4. This enables a comparison of functional levels of processing in the different systems and also provides a basis for modelling motor systems with attractor neural networks.


Effects of dehydration and rehydration on the intravascular space in horses.

1. The resistance of sub-tropical horses, and desert-dwelling horses to 72 hr dehydration/24 hr rehydration was investigated via changes in red cell parameters and plasma protein concentration. 2. Red cell count, haemoglobin and haematocrit increased up to 48 hr dehydration. Between 48 and 72 hr dehydration these parameters decreased, implying a fluid shift onto the intravascular space from the interstitium/hindgut. Most parameters had regained baseline values by 24 hr rehydration. 3. Mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration and total plasma protein were not significantly different between breeds at, or between most stages of hydration. 4. Protection of plasma volume during dehydration/rehydration was aided by maintaining intravascular protein (especially albumin) levels. Red cells were transiently dehydrated and overhydrated but resisted osmolysis.


Age influences on amino acid intestinal transport.

1. Intestinal absorption of amino acids show a decrease with aging in different animal species such as avians, rodents and ruminants. 2. The different intestinal segments show different absorptive capacities, the jejunum being the most absorbent. 3. Chickens show the biggest capacity for amino acid absorption close to hatching. 4. In rodents the third week seems to be the period of increased transport capacity.


An in vitro study of short-chain fatty acid concentrations, production and absorption in pig (Sus scrofa) colon.

1. Short-chain fatty acid concentration was 180 mmol/l in the proximal colon and decreased to 108 mmol/l in the rectum. 2. Fermentation in chymus from different regions of the colon, showed the pattern of end products to reflect the substrate and not the site of the colon. 3. Isolated mucosa from proximal and distal colon had electroneutral sodium absorption of 4.8 +/- 0.2 and 2.9 +/- 0.8 mueq/cm2 hr in bicarbonate free media, which was abolished in the absence of chloride. 4. Electroneutral sodium absorption was enhanced by short-chain fatty acids in the proximal colon and could be described by Michaelis-Menten kinetics with Km 2.0-11 mmol/l and Jm 1.6-3.6 mueq/cm2 hr. In the distal colon the stimulation was smaller and propionate even inhibited sodium absorption. 5. Butyrate was absorbed in the proximal colon, whereas acetate and propionate, and butyrate in the distal colon had a flux ratio of one. 6. Amiloride (5 mmol/l) inhibited sodium absorption and net butyrate absorption.


Influence of dietary sources of fat on lipid synthesis in mink (Mustela vison) mammary tissue.

1. The fatty acid composition of the triglyceride fraction of mink milk sampled during mid-lactation (day 28 post partum) from two nursing mink was compared to that of plasma samples and to the fatty acid composition of the feed rations used. 2. Chemical analysis of the triglyceride composition of mink milk demonstrated only minute concentrations of fatty acids with a chain length below C14. 3. The saturated C16:0- and C18:0-unit fatty acids in mink milk made up for 24-40% of the total amount of fatty acids extracted, the remainder being represented by mono and polyunsaturated long-chain (C16-C24) fatty acids. 4. Preliminary in vitro experiments proved the incorporation of 14C-labelled glucose, acetate or palmitate into triacylglycerols in cultures of mink mammary tissue to be linear for at least 2 hr. 5. The in vitro capacity for de novo fatty acid synthesis in mink mammary tissue using 14C-labelled glucose or acetate was low, i.e. ranging from 0.096-0.109 nmol/g (fresh tissue)/min, and amounted to only about 5% of that obtained in the case of [14C]palmitic acid incubation. 6. Following 14C-labelled acetic or palmitic acid incubation of mink mammary tissue neither desaturation nor chain elongation was observed. 7. In response to long-term feeding on rations with two different sources of animal fat (F = fish oil or L = lard) the influence of compositional changes in dietary neutral lipids on the fatty acid composition of the lipids of mink milk is discussed.


Effects of arterial insufficiency on glucose uptake by fast and slow rat skeletal muscles.

1. Muscle wet weight and glucose uptake were measured in female Wistar rats 7 and 14 days after unilateral ligation and section of the artery. 2. Following the induction of arterial insufficiency, muscle wet weight decreased significantly in the extensor digitorum longus (EDL), but not in the soleus muscle (Sol). 3. Muscle glucose uptake per wet weight increased significantly in EDL after arterial insufficiency, but not in Sol. 4. It is suggested that arterial insufficiency influences the metabolic control of fast muscle via anoxia as a main etiologic factor.


Circulating vasotocin in the snake Bothrops jararaca.

1. There is biochemical and pharmacological evidence to suggest the presence of vasotocin in the blood and plasma of the snake Bothrops jararaca (Bj). 2. XE-64 extracts from Bj blood showed antidiuretic and hypotensive activities in rats and a contractile effect on rat isolated uterus, which was totally dialysable and inhibited by thioglycollate. 3. Extracts from Bj whole plasma presented an antidiuretic activity which was only partially dialysable. 4. The plasma extracts also showed oxytocic properties. 5. When EDTA and Sep-Pak C18 extraction were used, a better recovery and characterization of vasotocin by HPLC was obtained. 6. These results indicate the occurrence of free and bound circulating vasotocin in Bj, in an equilibrium dependent of its enzymatic hydrolysis.


Adrenocortical responsiveness to immobilization stress in spotted hyenas (Crocuta crocuta).

1. The adrenocortical responsiveness to an induced stressor was monitored in free-living spotted hyenas belonging to a number of social and reproductive categories. 2. No significant differences between sexes, or changes in mean cortisol concentrations during serial sampling within the sexes, could be demonstrated. 3. The extreme individual variance in temporal cortisol profiles recorded in this study is inexplicable, as it was not related to differences in immobilization procedure, sex, age, reproductive or social category. 4. Females, which are the dominant sex in this species, generally showed larger percentage increases in cortisol concentrations during serial sampling. 5. Significant correlations between initial cortisol concentrations, as well as cortisol responsiveness and androgen concentrations, in a number of social and reproductive categories, suggest that these categories do not provide sufficient resolution for the identification of specific dominance-related trends.


Dye-coupling among frog (Rana catesbeiana) taste disk cells.

1. Dye-coupling among taste disk cells in the bullfrog fungiform papillae was examined histologically by injecting a fluorescent dye (Lucifer yellow) into the cell, and the effects of the dye-coupling on depolarizing responses induced by taste stimuli were studied electrophysiologically. 2. With dye injection into a taste cell, dye-coupling was found between taste cells (23%) or between taste cell and supporting cell (28%). With dye injection into a supporting cell, dye-coupling was found between supporting cells (34%) or between supporting cell and taste cell (27%). 3. Depolarizing responses recorded from either a taste cell or a supporting cell to stimulation with 0.5 M NaCl or 10 mM quinine-HCl were the same in amplitude whether the dye-coupling to another cell was present or not. On the other hand, depolarizing responses recorded from a taste cell for 0.5 mM acetic acid became significantly larger when dye-coupled to a supporting cell. 4. It is concluded that gustatory transduction for acid stimuli is influenced by supporting cells coupled to taste cells.


The biosynthesis of polyunsaturated fatty acids by rat sertoli cells.

1. The biosynthesis of polyunsaturated fatty acids (PUFA) of the n-6 and n-3 series was investigated in cultured Sertoli cells. 18:2n-6, 18:3n-6, 20:2n-6, 18:3n-3 and 20:3n-3 were added individually at a concentration of 20 mumol to culture media. 2. Maximum incorporation of 20- and 22-carbon PUFA into membrane lipids was observed after 72 hr of incubation with all the exogenous substrates used. 3. As reported in other cell systems, the delta 6 desaturation was the first rate-limiting step; the major factor regulating this activity was the concentration of linoleic acid or alpha-linolenic acid in the medium. 4. Our data show that the delta 5-desaturation represents a second regulatory step in PUFA biosynthesis. 5. The sum of n-6 and n-3 PUFA of the 22 carbon chain length constantly represented between 11 and 12% of total fatty acids, regardless of the exogenous substrate used. 6. Our kinetic studies of the incorporation of PUFA of the n-6 and n-3 series did not permit detection of a delta 8 desaturase activity.


User requirements and standards for PACS. 2nd Japan-Nordic PACS Symposium.

PACS has been regarded as a system which will bring a new era to image handling, radiology departments and its services to other departments of the hospital. However, many recently held international conferences indicate that a worldwide consensus on 'what is PACS, why is PACS needed and who is PACS for' has not been established. Although the actual PACS implementation will vary among the countries and according to each situation, a worldwide consensus of PACS should be possible. This would help those involved to speed up the implementation of PACS. It is suggested that this consensus needs to be developed by convergence of three points of view; the availability, maturity and cost of the technologies on which PACS is built, the user requirements for PACS and standardization in PACS. These themes were the topics of the 2nd Japan-Nordic PACS Symposium which was arranged in Tampere, Finland, June 9-11th 1991. A summary of the papers and discussions of the symposium is produced in this paper.


Do the benefits outweigh the costs of PACS? The results of an International Workshop on Technology Assessment of PACS.

On May 26-27, 1991, an International Workshop on the Technology Assessment of PACS was held at Enkhuizen, The Netherlands. During this workshop 35 experts in the field, from 13 different countries, discussed amongst others the required functionality of PACS, diagnostic aspects and the quality of care and organizational aspects. The key question was whether, when and how PACS is feasible, both from a financial and a clinical point of view. Data which were collected with the aid of the software tool CAPACITY formed the starting point of this meeting. This paper gives an outline of the discussions during this workshop. The main conclusion is that more clinical research is needed, to get a better insight into the costs and the clinical benefits of PACS. Because of the high costs of the PACS technology, international cooperation in this field is requested. It is recommended that the CAPACITY project, which is set up to stimulate the international dialogue and data exchange on PACS, is continued.


Cross-reactivity with Tagetes in Arnica contact eczema.

A 69-year-old patient, with known mercury and adhesive plaster allergy, developed facial dermatitis within 24 h of contact with arnica (Arnica). Skin testing showed positive reactions to arnica and, among various other plants of the Compositae, also to Tagetes sp. hybr. (marigold). Cross-reactivity between Tagetes and arnica has not previously been described.


DSM-II personality characteristics of panic disorder with agoraphobia patients in stable remission.

The Personality Diagnostic Questionnaire (PDQ), a self-rating scale designed to assess DSM-III axis II personality disorders (PD), was administered to 12 panic disorder with agoraphobia patients during a 6-month stable and virtually symptom-free remission period with the aim of assessing the personality characteristics of these patients in the best possible approximation of the not-ill condition in clinical reality. The personality profile of the sample remained unchanged during remission and was predominated by avoidant PD traits. In a finer grain analysis, the stable and commonly endorsed individual PDQ items were compared with previously reported panic disorder and normal control subjects, which showed that the present sample was more like the panic patients in their tendency to see themselves as rather unassertive, indecisive, self-critical, and emotional individuals who are easily frustrated and feel rejected when criticized by others. These results suggest that avoidant behavioral and attitudinal patterns may be enduring personality characteristics of panic disorder with agoraphobia patients.


[A study on virus localization and microcirculation in the liver in patients with epidemic hemorrhagic fever].

The findings in our clinical study was consistent with those reported by others that a temporary elevation of serum alanine aminotransferase activity is associated with epidemic hemorrhagic fever (EHF). However, the pathogenesis of the concomitant changes in liver function tests is still not clear. To clarify whether EHF virus is cytopathic or not for the liver, percutaneous liver biopsy was done in 19 patients with EHF within 3-12 days after the onset of symptoms. These liver biopsy specimens were examined with immunofluorescence assay and cell cultural technique, showing the presence of active viral replication in liver cells. Electron microscopy observation of the infected liver cells showed that ultrastructural distortions was accompanied by the existence of inclusion bodies of EHF virus in vacuoles of rough endoplasmic reticulum, endotheliocyte and microvilli. These findings strongly suggest that EHF virus may play a causative role in liver injury in patients suffering from EHF and hepatic microcirculation disturbance may be involved in the pathogenesis of EHF-related liver dysfunction as well.


[A study on pathogenesis and therapy of hemorrhagic fever with renal syndrome].

581 early cases of typical hemorrhagic fever with renal syndrome (HFRS) were dynamically studied on the clinical manifestations and laboratory findings from 1986 to 1989. All the patients were treated with various methods. The results showed: (1) The manifestations of microvascular damage, proteinuria and thrombocytopenia can be found at the first day of the onset in 80.0%, 72.2% and 33.3% respectively. In a word, the characteristic features of HFRS appear at the onset of the disease. (2) In 446 early cases the initial severity of the disease corresponded with the final severity at a rate of 89.2%; it indicated that the damage of HFRS may result from the first attack. (3) The time of the onset, peak and persistence of all the characteristic features were similar; it is suggested that the course of HFRS may be self-limited. (4) Based on the clinical understanding and the effective results in the 446 early cases treated with fluid therapy alone, we consider that the effective treatment of HFRS is early and reasonable fluid therapy.


Ca(2+)-cyclic AMP interactions in sustained cellular responses.

As early as 1970 it was apparent that the cyclic AMP (cAMP) and Ca2+ messenger systems often interact to regulate cellular responses. Work over the past 20 years has greatly expanded our knowledge of these interactions, and has shown that these signalling systems interact in complex ways to regulate sustained cellular responses such as aldosterone secretion, smooth muscle contraction and insulin secretion. The latter system is considered in detail because it illustrates several types of interactions, both positive and negative, which help to determine the normal response of beta-cells to physiological stimuli, and how abnormalities in secretory patterns can develop as a consequence of the prolonged stimulation of a messenger system.


[The correlation between clozapine saliva level and clinical response as well as side effect in patient with schizophrenia].

It was measured for clozapine saliva level in 62 patients with schizophrenia taking clozapine, the study have found that therapeutic window was at the range from 550 ng/ml to 920 ng/ml in 34 patients with duration more than two years and was at the range from 400 ng/ml to 510 ng/ml in 28 patients with duration less than two years. Clozapine saliva concentration has positively correlated with improvement of though disorders and hostility & suspiciousness in 30 patients with duration more than two years and with improvement of activation in 12 patients with duration less than two years and with anti-adrenergic side effect in 62 patients, the latter effect was significant increased when clozapine saliva level was more than 380 ng/ml.


[A study on transmission of epidemic hemorrhagic fever virus through skin wounds among rodents in natural conditions].

224 rodents captured from endemic areas of epidemic hemorrhagic fever (EHF) in Hubei province were examined for the presence of skin wounds and EHF viral antigens and antibodies by immunofluorescent assay (IFA) technique. It was found that 30.8% (69/224) of the captured rodents had skin wounds and that 24.6% (17/69) and 29.0% (20/69) of the wounded rodents were positive respectively to EHF viral antigens and antibodies, as compared with the corresponding rates of 9.0% (14/155) and 8.4% (13/155) in rodents without skin wounds. This suggests that infection through skin wounds could be an important route of transmission of the EHF virus among rodents under natural conditions.


[Preliminary studies on c-erbB-2 protooncogene in breast cancer].

c-erbB-2 protooncogene amplification was analyzed with Southern blot technique in 50 breast cancer patients in an attempt to correlate the results with the prognosis. The median follow-up was 59 months. Amplification was found in 15/50 (30%) of these patients including two cases of rearrangement. A highly statistically significant difference was found in postoperative survivals of patients with or without c-erbB-2 amplification (P less than 0.005). When patients were divided into groups by stage, nodal status, tumor size and PR status, the prognosis tended to become worse with c-erbB-2 amplification. It was demonstrated that the postoperative median survival of Stage I and II patients with amplification was similar to those of Stage III and IV patients without amplification (48 and 47.8 months). The postoperative median survival of node negative patients with amplification was shortened as compared to those of node positive ones without amplification (47.3 and 54 months). This observation indicates that c-erbB-2 amplification seems to be an useful independent prognosis indicator in breast cancer, particularly in identifying the subsets of high risk of recurrence in node negative or Stage I and II patients.


Metabolism of the leukotriene receptor antagonist 5-(2-(8-phenyloctyl)phenyl)-4,6-dithianonanedioic acid (SK&F 102922) in the guinea pig. Rearrangement of the acyl glucuronide.

A primary route of inactivation of leukotrienes and their receptor antagonists (LTRA) is metabolism by omega oxidation. SK&F 102922 [5-(2-(8-phenyloctyl)phenyl)-4,6-dithianonanedioic acid] is a LTRA that was designed to be resistant to omega oxidation. Therefore, these experiments were designed to characterize the metabolic fate of [14C]SK&F 102922. Following iv administration of SK&F 102922 (5 mg/kg), 80% of injected radioactivity was excreted in bile in 1 hr. At least five metabolites and parent (18% of administered dose) were present in bile. One metabolite (M1), which accounted for less than 10% of the excreted radioactivity, was monohydroxylated. Three metabolites (M2, M3A, and M3B), which together accounted for greater than 50% of excreted radioactivity, had mass spectra consistent with acyl glucuronides. All three metabolites were alkali labile, whereas only one metabolite (M2) was susceptible to beta-glucuronidase hydrolysis. These data indicate that M3a and M3b are nonglycosidic isomers of M2 that were formed by a nonenzymic reaction involving migration of the aglycone (SK&F 102922) from C-1 to C-2, C-3, or C-4 of glucuronic acid. The 1-O-acyl-beta-glucuronide of SK&F 102922 (M2) exhibits pH dependent rearrangement, with half-lives ranging from 1 to greater than 1000 hr. Therefore, acyl glucuronidation can account for much of the metabolic fate of SK&F 102922 and, potentially, other structurally related LTRAs or endogenous leukotrienes themselves.


A physiologically based pharmacokinetic model for (-)-quinuclidinyl benzylate using nonlinear irreversible tissue binding parameters in rats.

The disposition characteristics of (-)-quinuclidinyl benzylate (QNB) were investigated in rats, and a physiologically based pharmacokinetic model was established using its linear and nonlinear tissue binding parameters. The steady-state distribution volume (Vdss) and systemic clearance (CLtot) were comparable after iv administration of 325 ng/kg and 3.2 mg/kg, suggesting that QNB pharmacokinetics based on plasma concentrations is linear. However, tissue accumulation was observed in the heart, lung, muscle, and brain. This accumulation persisted for over 12 hr after the iv administration of 325 ng/kg [3H]QNB. Tissue binding parameters were determined after continuous infusion of QNB. Irreversible and nonlinear binding parameters were obtained in various regions of the brain and other tissues. Reversible equilibrium concentration ratios between tissue and plasma were determined after high-dose infusion. QNB concentrations in the plasma, heart, lung, muscle, and brain were predicted after the administration of 325 ng/kg or 3.2 mg/kg. There was reasonable agreement between the model predictions and the observed data.


Effects of dose, sex, and age on the disposition of alendronate, a potent antiosteolytic bisphosphonate, in rats.

Alendronate (4-amino-1-hydroxybutylidene-1,1-bisphosphonate), an antiosteolytic agent, is currently under investigation in the treatment of a variety of bone disorders. Earlier studies from this laboratory have demonstrated that systemically administered drug was rapidly taken up by bone tissue or excreted by the kidneys. Approximately 60 to 70% of the dose was taken up by the bone, and 30 to 40% was excreted in the urine. The purpose of this study was to determine the effects of dose, sex, and age on the disposition kinetics of alendronate using rats as an animal model. No evidence of saturation of drug uptake by the bone was observed in young rats when small, repetitive doses of alendronate were administered every 3 days for 21 days (total 35 mg/kg iv). However, less than proportional uptake by the bone was observed in young rats when single iv doses exceeded 10 mg/kg. Overall, a 500-fold increase in dose resulted in a 350-fold increase in drug concentration in bone. Nonlinear uptake of alendronate by bone was accompanied by simultaneous accumulation in noncalcified tissues at high doses. Less than 1% of the dose was found in noncalcified tissues at 24 hr after low doses (1 mg/kg iv), and 25% after high doses (30 mg/kg iv). Following iv administration, uptake of alendronate by the bone was lower in senescent rats than in young rats by a factor of 2 to 3. Bone uptake was lower in female rats than in male rats by about 30 to 40%, but this sex difference was only observed at low doses and in young rats.


Metabolism of simultaneously administered antipyrine and theophylline in male BN/BiRij rats before and after induction with 3-methylcholanthrene.

In order to study the metabolic activities of different P-450 enzymes in male Brown Norway rats, formation rates of antipyrine (AP) metabolites and theophylline (TH) metabolic clearance were determined. Brown Norway rats are often used in studies concerning the influence of age on liver function. Experiments were performed after simultaneous iv administration of the two compounds with and without 3-methylcholanthrene (3-MC) pretreatment. Pharmacokinetic data of both AP and TH were significantly influenced by 3-MC pretreatment. Metabolic clearance of AP increased from 6.8 +/- 1.0 (mean +/- SD, N = 23) to 18.4 +/- 7.9 (N = 10) ml.min-1.kg-1, whereas the metabolic clearance of TH increased from 1.9 +/- 0.6 to 20.0 +/- 5.1 ml.min-1.kg-1. Elimination half-life in plasma decreased from 77 +/- 10 to 33 +/- 9 min for AP and from 171 +/- 36 to 25 +/- 7 min for TH, respectively. Urinary recovery as the metabolites 3-hydroxymethylantipyrine, 4-hydroxyantipyrine, and norantipyrine accounted for approximately 36% of the administered dose in the control situation, and for approximately 21% after 3-MC pretreatment. 3-MC pretreatment strongly reduced the formation of 3-hydroxymethylantipyrine, but increased the formation rate of 4-hydroxyantipyrine and norantipyrine. Weak correlations were found between the clearances of formation of the AP metabolites and the metabolic clearance (CLm) of TH in the control rats. This may be caused by a large contribution of constitutive P-450 enzymes in the formation of AP metabolites and/or the metabolic clearance of TH in Brown Norway rats.(ABSTRACT TRUNCATED AT 250 WORDS)


Lack of effect of streptogramins on hepatic drug metabolism enzymes in the rat.

Male Sprague-Dawley rats were treated with streptogramin derivatives (RP 7293, RP 54476, RP 57669, and RP 59500) or with the macrolide troleandomycin. Liver cytosol and microsomes were prepared, and the in vitro transformation of several model substrates studied. Furthermore, total and complexed microsomal cytochrome P-450 levels were compared. Hepatic cytochrome P-450 metabolite complexes were detected 4 days after troleandomycin treatment (500 mg/kg/day po), whereas such effects were not observed with po RP 7293 (500 mg/kg/day, 4 days) or with iv RP 54476 (12 mg/kg/day, 7 days), RP 57669 (6 mg/kg/day, 7 days), or RP 59500 (6 and 18 mg/kg/day, 7 days). The administration of troleandomycin resulted in statistically significant increases in liver weight (+20%), microsomal protein (+70%), total cytochrome P-450 (+187%), and cytosolic glutathione S-transferase activity (+32%). The activities of aniline hydroxylase, aminopyrine N-demethylase, and the high and low phases of 7-ethoxyresorufin O-deethylase were markedly decreased by 36% to 56%. In contrast, none of these hepatic parameters was changed significantly after administration of each streptogramin. These results suggest that streptogramins have not, in contrast to many commonly used macrolide antibiotics, had potent or specific effects on hepatic drug metabolizing enzymes in rats.


Probenecid-impaired biliary excretion of acetaminophen glucuronide and sulfate in the rat.

Acetaminophen (APAP; 100 mg/kg iv) and probenecid (50 mg/kg bolus + 11.4 mg/hr/kg infusion) were administered to male Sprague-Dawley rats to examine the disposition of APAP, and its glucuronide (AG) and sulfate (AS) conjugates in plasma, bile, and urine. Probenecid significantly decreased the formation clearance of AG from 3.65 +/- 0.434 to 1.94 +/- 0.441 ml/min/kg and the renal clearance of AS from 9.32 +/- 2.26 to 3.15 +/- 1.21 ml/min/kg. The biliary excretion of AG was reduced approximately 3- to 4-fold by probenecid, from 6.54 to 1.87% of the APAP dose, and the AG biliary excretion rate was decreased 4- to 5-fold during probenecid treatment. The more extensive impairment of AG biliary excretion relative to AG formation suggests that probenecid may inhibit the hepatobiliary transport of AG. The significant reduction in the biliary excretion rate at early time points for AS suggests that probenecid may inhibit hepatic AS transport. The study results indicate that probenecid impairs AG and AS formation, AS renal secretion, and AG and AS biliary excretion.


Noninvasive in vivo 13C-NMR spectroscopy in the rat to study the pharmacokinetics of 13C-labeled xenobiotics.

Noninvasive NMR methodology has been developed to enable monitoring of 13C-labeled xenobiotics in the rat in vivo. 2,2-Dichloro-1-(2-chlorophenyl)-1-(4-chlorophenyl)-[3-13C]-propane can be detected in the liver of intact rats by in vivo 13C surface coil NMR spectroscopy after ip administration of the compound. The experiments were performed at 1.9 and 9.4 Tesla. The intrahepatic changes of the signal intensity of the labeled compound were followed as a function of time. In the days following administration, the concentration decreased and dropped to values below the detection limit after 12 days. The study demonstrates the feasibility of studies on pharmacokinetics of 13C-labeled compounds in the rat using noninvasive, in vivo surface coil NMR spectroscopy in animals. The sensitivity allows the detection of a single dose of the drug of 200 mg/kg, but can be improved.


Dominant role of cytochrome P-450 2E1 in human hepatic microsomal oxidation of the CFC-substitute 1,1,1,2-tetrafluoroethane.

The chlorofluorocarbon substitute 1,1,1,2-tetrafluoroethane (HFC-134a) is subject to metabolism by cytochrome P-450 in hepatic microsomes from rat, rabbit, and human. In rat and rabbit, the P-450 form 2E1 is a predominant low-KM, high-rate catalyst of HFC-134a biotransformation and is prominently involved in the metabolism of other tetrahaloalkanes of greater toxicity than HFC-134a [e.g. 1,2-dichloro-1,1-difluoroethane (HCFC-132b)]. In this study, we determined that the human ortholog of P-450 2E1 plays a role of similar importance in the metabolism of HFC-134a. In human hepatic microsomes from 12 individuals, preparations from subjects with relatively high P-450 2E1 levels were shown to metabolize HFC-134a at rates 5- to 10-fold greater than microsomes of individuals with lower levels of this enzyme; the increased rate of metabolism of HFC-134a was specifically linked to increased expression of P-450 2E1. The primary evidence for this conclusion is drawn from studies using mechanism-based inactivation of P-450 2E1 by diethyldithiocarbamate, competitive inhibition of HFC-134a oxidation by p-nitrophenol (a high-affinity substrate for P-450 2E1), strong positive correlation of rates of HFC-134a defluorination with p-nitrophenol hydroxylation in the study population, and correlation of P-450 2E1 levels with rates of halocarbon oxidation. Thus, our findings support the conclusion that human metabolism of HFC-134a is qualitatively similar to that of the species (rat and rabbit) used for toxicological assessment of this halocarbon.(ABSTRACT TRUNCATED AT 250 WORDS)


Effects of pregnancy and ethanol treatment on the metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone by hamster liver and lung microsomes.

The tobacco-specific N-nitrosamino 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a potent carcinogen in adult Syrian golden hamsters and causes a high incidence of tumors in the offspring of hamsters after in utero exposure. We have investigated how pregnancy and/or ethanol treatment modulates the microsomal metabolism of NNK. Pregnancy decreased the alpha-carbon hydroxylation (activation) of NNK, whereas it increased both the pyridine N-oxidation and carbonyl reduction of NNK in liver microsomes, but not in the lung. Ethanol treatment of nonpregnant hamsters induced both the hepatic microsomal alpha-carbon hydroxylation and pyridine N-oxidation of NNK, but it increased only the formation of NNAL, the N-nitroso alcohol NNAL, in the lung. Ethanol-consuming pregnant hamsters showed no changes in the hepatic or pulmonary metabolism of NNK. In contrast, fetal hamsters exposed in utero to ethanol showed a general increase in the rate of metabolism of NNK. Immunoblot analyses demonstrated a reduction in the P-450IIE1 and total P450IIB1/IIB2 protein levels in the liver of pregnant hamsters, whereas a moderate increase of P-450IIB1 was observed in the lung. Moreover, ethanol treatment increased the amount of immunodetectable P-450IIE1 and total P-450IIB1/IIB2 in the liver of nonpregnant hamsters, but only the hepatic P-450IIE1 was induced by ethanol in pregnant hamsters. The P-450IIB1 protein levels were not affected by ethanol treatment in the lung of nonpregnant, pregnant, or fetal hamsters. In contrast, the fetal hepatic P-450IIE1 and P-450IIB1/IIB2 protein levels were increased by transplacental ethanol exposure.(ABSTRACT TRUNCATED AT 250 WORDS)


Pharmacokinetics of azelastine and its active metabolite, desmethylazelastine, in guinea pigs.

Pharmacokinetics of azelastine (AZ) and its major active metabolite desmethylazelastine (DAZ) after iv or po administration of 1 mg/kg [14C]AZ hydrochloride or unlabeled AZ hydrochloride were studied in guinea pigs. Total 14C radioactivity concentrations in blood, plasma, lung, urine, and feces were determined by liquid scintillation counting. AZ and DAZ concentrations in the plasma and lung samples were determined by HPLC methods. For pharmacokinetic modeling, the mean concentrations of AZ and DAZ in plasma were converted to those in blood. Following the iv or po dose, AZ blood concentrations declined biexponentially with the distribution and elimination phases. The open two- and one-compartment models for AZ and DAZ concentrations in blood, respectively, and the open one-compartment model for the two compounds in lung tissue describe the experimental data reasonably well. The apparent volume of distribution of AZ suggested that the drug was widely distributed in the body. The mean lung/blood concentration ratios, which varied from 14.2 to 20.1 in the iv- and po-dosed animals for AZ and from 96.7 to 140.3 in the iv- and po-dosed groups for DAZ, respectively, indicate the capacity of the lung ("target tissue") for preferential uptake of the drug and its active metabolite. The efficiency of the desmethyl metabolite uptake into the lung was about 6-fold greater than that of AZ. The clearance of AZ from the body was faster than that of DAZ following either po or iv administration. The estimated availability of the AZ oral dose in guinea pigs was 0.19, which suggested that AZ was subjected to an extensive hepatic first-pass metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)


Tissue distribution and lung localization of [14C]azelastine in guinea pigs.

Tissue distribution was performed in male guinea pigs that received a single oral dose of 1 mg/kg [14C]azelastine. Determination of 14C concentrations by liquid scintillation counting in 16 tissues and by whole-body autoradiography showed preferential uptake of the radioactivity by the lung. The liver had a higher and all other tissues had lower concentrations of 14C than the lung. The lowest 14C concentrations were in the eyes and brain. Light microscopy autoradiography of lung and trachea sections indicated localization of 14C, possibly in alveolar macrophages. The radioactivity cleared completely from lung tissue, as well as from other tissues within 48 hr.


Effects of low-density lipoprotein and ethinyl estradiol on cyclosporine metabolism in isolated rat liver perfusions.

The effects of low-density lipoprotein (LDL) on cyclosporine (CyA) metabolism were studied in the isolated perfused rat liver, in a recirculating mode, using Krebs-Ringer buffer in the absence (control perfusion) or presence of LDL (1 microM) (LDL perfusion). In the LDL perfusions, CyA concentrations at all sampling times were about 2-fold higher, whereas the biliary excretion of CyA and measured metabolites (AM1, AM9, AM1c, and AM4N) were all lower than those obtained with the control perfusions. At the end of the perfusion (3 hr), the percentage of total CyA remaining (liver, bile, and perfusate) was significantly higher (76 +/- 1.2% to 85 +/- 2.4%) and the percentage of dose metabolized to AM9 was lower (4.8 +/- 1.2% to 2.4 +/- 0.6%) in the LDL perfusions (N = 4). These results further suggest the inhibitory effects of LDL on CyA uptake, and, thereby, its metabolism as we observed previously in isolated rat hepatocyte studies. Because ethinyl estradiol (EE) is known to increase LDL receptors in rats, we investigated the possible involvement of LDL receptors in transporting CyA into liver cells using rats pretreated with EE (5 mg/kg/day sc for 5 days). The effects of LDL in maintaining CyA perfusate concentrations, and in decreasing biliary excretion of CyA and its metabolites in the EE-treated animals, were in the same direction as those noted in animals without EE, but the differences due to LDL were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)


Total body and hepatic clearance in rats of recombinant tissue-type plasminogen activator expressed in mouse C127 and Chinese hamster ovary cells.

The total body and hepatic clearance of two recombinant human tissue-type plasminogen activators (t-PA) produced in mouse C127 cells [t-PA(C127)] and in Chinese hamster ovary cells [t-PA(CHO)] were determined in rats. Recombinant t-PA was administered as a constant iv or intraportal venous infusion for 60 min. The plasma t-PA level over 120 min was measured by an ELISA. Whole-body pharmacokinetics were characterized in terms of the total body clearance (CLt), total volume of distribution, and mean residence time in the body. Hepatic disposition was described by the hepatic clearance (CL(hep)) and the mean hepatoportal transit time. Whereas a marked hepatic extraction was observed with both t-PAs, the estimated CL(hep) accounted for only one-half the Clt. No elimination took place in the lung, because no difference was observed between iv and intraarterial administration. Extrahepatic elimination, such as that in circulating blood, appeared to play a significant role in the disposition of t-PA in vivo. t-PA(C127) is known to possess the Gal alpha 1-3Gal epitope in its complex-type carbohydrate chains, whereas this structure is not involved in t-PA(CHO). In the presence of Bandeiraea simplicifolia lectin I isolectin B4, which is specific to the Gal alpha 1-3Gal, the Clt of t-PA(C127) was significantly decreased, whereas that of t-PA(CHO) was unchanged. These results imply that the formation of a high molecular weight complex by this carbohydrate epitope effectively reduces the rate of catabolism of t-PA in vivo.


Effect of miconazole on warfarin disposition in rabbits.

To elucidate the mechanism underlying the reported potentiation of warfarin anticoagulant action after initiation of miconazole therapy, the effects of acute and chronic miconazole administration on warfarin disposition were examined in six adult New Zealand male rabbits. The rabbits received a 3.5 mg/kg iv dose of warfarin either alone, 1 hr after a single 100 mg/kg ip miconazole dose, or on day 5 of a 6-day 50 mg/kg/12 hr ip miconazole dosing regimen. Acute miconazole administration decreased the elimination rate constant of warfarin, but other warfarin disposition parameters were not altered. Chronic miconazole administration caused a 47% increase in warfarin plasma-free fraction (probably caused by competitive or noncompetitive protein binding displacement by miconazole metabolites) and a 42% decrease in warfarin intrinsic clearance (probably caused by a miconazole-induced inhibition in warfarin metabolism). As a consequence of these quantitatively similar but opposite changes, the total body clearance of warfarin (a low clearance drug) was marginally decreased. A significant decrease in the elimination rate constant and an increase in the tissue-free fraction of warfarin were also observed during chronic miconazole treatment. These results suggest that chronic miconazole administration should not significantly affect the steady-state plasma concentrations of total warfarin, but should increase the steady-state plasma concentrations of free warfarin. The expected increases in the steady-state plasma concentrations of free, pharmacologically active warfarin may account for the reported potentiation of the pharmacological action of warfarin when coadministered with chronic miconazole. Measurement of total plasma concentrations, and estimation of total body clearance might be misleading, and inadequate in identifying certain drug interactions involving low clearance drugs.


Metabolism of [14C]azelastine in guinea pigs.

A specific HPLC separation method was used to generate 14C metabolite profiles in lung, muscle, and liver tissue and in bile, urine, and feces obtained from male guinea pigs that received a single oral dose of 1 mg/kg [14C]azelastine. Profiles were also generated in urine and feces of animals that received a single iv dose of labeled drug. In lung and muscle tissue, azelastine (AZ) and desmethylazelastine (DAZ) were the major components of 14C radioactivity. The amount of the amino acid metabolites (2- and 7-ACID), formed by oxidation and azepinyl ring opening, was relatively small. In the liver significant amounts of the 7-ACID were observed in addition to AZ and DAZ. The major metabolite in bile, urine, and feces was the 7-ACID, with much less AZ and DAZ present. The balance of 14C in the form of AZ and three metabolites in excreta (percentage of dose) was: AZ, 9.7-10.5%; DAZ, 8.7-9.6%; 2-ACID, 2.9-3.0%; and 7-ACID, 43.0-54.6%. No large differences in the quantitative profile between the two dosing routes were observed.


12 alpha-hydroxytestosterone. A hitherto unidentified testosterone metabolite produced by cytochrome P-450 2A2.

Several cytochrome P-450 enzymes are able to hydroxylate testosterone to many different metabolites, some of which remain to be identified. One hitherto unidentified metabolite represents a major metabolite of P-450 2A2, present in the liver of adult male rats, and a minor metabolite of several other cytochrome P-450 enzymes. Using the techniques of HPLC and GC/MS, we have obtained unequivocal evidence that this metabolite is 12 alpha-hydroxytestosterone.