[Interferon as a bronchospastic factor in patients with bronchial asthma].

Twenty three asthmatics were examined during the symptoms free period. Each subject inhaled aerolised human interferon alpha (Hu IFN-alpha, Le) in increasing doses 4000 and 8000 units. IFN inhalation provoked significant decline in FEV1 (by 9.9% after the 1st dose and 6.6% after the 2nd dose on average). This results indicate that inhaled interferon induces bronchospastic reactions in asthmatics.


[Activity of glucose-6-phosphate dehydrogenase in erythrocytes in patients with atopic asthma and allergic rhinitis].

A significant decrease of erythrocyte G-6-P dehydrogenase activity in patients with atopic asthma and allergic rhinitis was observed. In order to define the cause of this phenomenon the enzyme was isolated from the cells. The kinetic and molecular properties of the erythrocyte G-6-P dehydrogenase were studied. A change in the Michaelis constant for G-6-P dehydrogenase was seen in erythrocytes of both patient groups. The thermoresistance at 45 C was reduced significantly. These modified properties can imply a change in the dehydrogenase molecule, this is seen more significantly in the group with allergic rhinitis.


[Studies on the possibility of desensitizing patients sensitive to plant pollens and house dust by an oral route].

Oral hyposensitization was carried out in 26 patients with pollinosis and in 67 patients sensitive to house dust with all year symptoms of allergic disease of the skin, airways or conjunctivitis. The patients were hyposensitized with grass pollen extracts and house dust produced by Lab. Sevac. The pollen allergen was administered before the pollinating season, in increasing doses during 18 weeks. The following concentrations were used: 0.1 PNU, 1.0 PNU, 10 PNU, 100 PNU, and 1000 PNU. The house dust allergen was administered in the same manner, using the same concentrations and time during autumn and winter. In the group of patients with plant pollinosis 10 out of 26 did not experience any symptoms of the disease after hyposensitization. In 9 further patients the symptoms were milder. In the group of 44 patients with atopic dermatitis sensitive to house dust, a complete cure was seen in 62% of the patients. In further 25% milder symptoms were observed. In the group of 11 patients allergic to house dust and with the asthma-prurigo syndrome, the respiratory and dermatologic symptoms resolved completely or diminished in 3 and 6 patients respectively. In the group of 7 patients with dermatitis and full year rhinitis, complete resolvement of symptoms was seen in 2 patients and diminished symptoms in 3 cases. In the group of 4 patients with conjunctivitis full resolvement of symptoms was observed in 3, while partial in 1. Only in 3 out of 93 treated subjects intolerance of this therapy was found.(ABSTRACT TRUNCATED AT 250 WORDS)


[Phenologic observations of the Rabka health resort in 1990].

Important factors decisive of the health resort's climatic characteristics are the results of aero-phenologic studies. These results take in account the different pollinating seasons of various plants, grasses and weeds. Quantification and qualification of air pollination using the volume method with a Burkhard analytical device. Basing on results the authors have found increasing pollination string from March. At his time the main pollens come from birch, hazel, alder, weeping willow. The concentration of these pollens decrease in April, completely diminishing in May. Grass pollens increase in mid-May, peaking in June to early August. Pine pollens are found in May and June. A characteristic feature of the phenologic calendar is pollination of grass and pines in the same period (late May and June). The results of this are seen in children treated at the Mother and Child Institute Branch in Rabka, who demonstrate increased signs of pollinosis. The results of this study should modify treatment and change prophylaxis in children treated in Rabka.


[Changes of alpha-amylase activity in serum and urine of patients with various histological types of lung cancer].

Serum and urinary activity of alpha-amylase was assessed in different types and clinical stages of lung cancer. Significantly increased activity was seen in adenocarcinoma and in stage III of the disease. Following surgical removal of the tumor alpha-amylase decreased on the 7th day by 19% and on the 21st day by 26.8%. The activity of urinary alpha-amylase also decreased. The authors have determined the thermostable fraction of the alpha-amylase which may imply the source of the enzyme in the serum.


[Foreign bodies in the bronchi of adult patients].

846 bronchoscopies were carried out in adults between 1.01.1988 and 31.01.1991. 11 of these were performed in order to remove endobronchial foreign bodies. In 5 cases the foreign bodies were located in the bronchi of the right lung. In 1 case the foreign body was localized in the left lung. All were removed bronchoscopically. The youngest patients had 54 years, the oldest 82. The author discussed the diagnosis and removal of endobronchial foreign bodies. No complications were observed.


[Pulmonary lymphangiomyomatosis].

A case of pulmonary lymphangiomyomatosis in a female during menopause is presented. Difficulties in correct histopathological assessment of lung biopsies were met. The diagnosis was made after diagnosis lymph seeping into the pleural cavity. The patient was initially treated with prednisolone, tamoxifen followed by methyl progesterone and after characterizing the patient's hormone profile with danazol. Lymph seeping to the right pleural cavity was treated with pleural drainage and diet limitations. Lymph exudate to the left pleural cavity was controlled with local cytotoxic therapy. After 7 years of therapy and 8 years since the initial symptoms the state of the patient has deteriorated although she can perform every day chores and does not require oxygen therapy. High resolution CT scan disclosed extensive pulmonary changes implying extensive progression of the disease.


[Lactate acidosis in the course of status asthmaticus--case report].

A case report of lactate acidosis in the course of status asthmaticus in a 34 year old female is presented. The lactate acidosis was due to increased anaerobic glycolysis in respiratory muscles caused by decreased oxygen recruitment and increased oxygen consumption by respiratory muscles. The authors discuss the clinical significance of lactate acidosis and proper treatment of status asthmaticus.


[Cellular bronchoalveolar lavage (BAL) components and pulmonary function in chronic extrinsic allergic alveolitis].

Bronchoalveolar lavage (BAL) and pulmonary function tests were carried out in 22 patients with chronic, extrinsic allergic alveolitis. In all a marked decrease of diffusion capacity was observed. The mean DLCO values was 34% predicted value. In 94% of the patients compliance was lowered. More pronounced abnormalities of pulmonary function (decrease of TLC and DLCO) were found with low BAL lymphocyte counts and increased macrophages count. The duration of the disease correlated with the absolute lymphocyte BAL count (r = -0.43). The BAL differential can be an additional measure of severity, duration of the disease process in chronic, extrinsic allergic alveolitis.


Treatment of portwine stains using the pulsed dye laser.

Five years of clinical experience of the treatment of portwine stains using the flashlamp-pumped dye laser is presented. The dye laser, when turned to a wavelength of 577 nanometres with a short pulsewidth of the order of 340 microseconds, may be used to target selectively the dilated vasculature constituting the lesion. Patients with ages ranging from 5-45 years were treated under general anaesthetic using a computer controlled scanning system developed by the authors. Several repeat treatments were found to be necessary. Results are presented ranging from total eradication of the lesion to marginal lightening only. No scarring of the treated sites was evident.


Management of the soft tissues in open tibial fractures.

This paper reviews the treatment of 168 open tibial fractures referred to the Northern Ireland Plastic Surgery Service over a 15-year period. Flap reconstruction was carried out in 133 (79%) and split skin graft cover in 22 (13%). There were 18 amputations (11%). There was a high incidence of complications among early post-injury fasciocutaneous flaps and late free flaps. Twenty-five primary free flaps were transferred without complication. The current management of open tibial fractures in this Unit is described.


Comparative analysis of tissue fluorescence as related to capillary perfusion in random pattern skin flaps.

In random pattern skin flaps of mice, tissue fluorescence measured by means of videodensitometry at 24 h after flap elevation significantly correlates with intravital microscopically measured functional vessel density and viability of skin tissue as assessed by transmission light and electron microscopy. The correlation was found reproducible in non-ischaemic flaps (r = 0.86) and flaps being rendered ischaemic for 6 h after elevation (r = 0.98), indicating that increased microvascular permeability as a result of ischaemia/reperfusion does neither affect tissue fluorescence nor the accuracy of the fluorescein dye test. In addition, tissue fluorescence at 24 h after flap elevation accurately predicts ultimate flap survival on the 7th postoperative day with a sensitivity of 0.89 and a specificity of 0.85. These results suggest that in non-ischaemic as well as in ischaemic random pattern skin flaps tissue fluorescence can be used for assessment of nutritive blood flow, viability of skin tissue and ultimate tissue survival in these flaps.


Neurocutaneous island flaps in the hand: anatomical basis and preliminary results.

The neurocutaneous flap is an axial flap composed of one vein and one nerve, the arterial vascularisation of which is provided by the vascular plexus around and inside the nerve. The vascularisation of the radial and ulnar nerves on the dorsal aspect of the hand were studied in 20 fresh upper limbs. There is always a consistent arterial longitudinal plexus alongside the nerves, which links the cutaneous perforating arteries. On the basis of our anatomical findings, neurocutaneous island flaps with retrograde flow were raised on the hands of five patients and are reported on.


Trimmed second toetip transfer for reconstruction of claw nail deformity of the fingers.

Claw nail deformities of the fingers have been repaired by many methods, but the results have been cosmetically unsatisfactory because of loss of the distal phalangeal bone and the short nail bed. We have employed a trimmed second toetip including the distal phalangeal bone and excluding the germinal matrix as a vascularised composite flap for two patients with claw nail deformity of the fingers. The advantages of this method are that the repaired nail regrows to normal size and has bilateral nail folds. We believe that, in comparison with other conventional local or island flaps, this composite flap is functionally and cosmetically ideal for the repair of claw nail deformities.


Desmoplastic melanoma: a clinico-pathological review.

Desmoplastic Melanoma (DM) represents a rare histological variant of melanoma. It has been described in isolated case reports as a cutaneous tumour with a high incidence of local recurrence and nodal metastases, requiring early aggressive surgery. However, overall clinical experience of the tumour is limited. 13 patients with DMM seen over a 20 year period were reviewed. The mean age at presentation was 67 years (range 34-87), and 2/3 of the lesions were in the head and neck. Tumour thickness averaged 5.78 mm (Breslow). 7 patients developed recurrence, 4 as regional nodes, and 3 as skin nodules. Four of these patients developed disseminated disease, of whom 3 died. The mean time to first recurrence was 26 months and mean follow-up time in the review was 40 months (range 3-141 months).


Simple line closure for macrostomia repair.

In repair of macrostomia, many authors have used a Z-plasty to prevent postoperative scar contracture. We found that the Z-plasty scar may be conspicuous when the patients open their mouths. Here we present a method of nearly straight line closure resulting in an inconspicuous scar even when the patients move their mouths.


Hydration and occlusion treatment for hypertrophic scars and keloids.

In 31 patients with hypertrophic scars or keloids, a side by side test was carried out to check the efficacy of an occlusive dressing technique using cream which did not contain silicone oil, versus a simple application of vaseline, used as a control. In all cases, the cream treated areas of scar and keloid demonstrated a remarkable improvement over that of the vaseline treated area. These findings strongly suggest that the mechanisms of hydration and occlusion are the main basis of the therapeutic action of this method in treating hypertrophic scars and keloids.


Reconstruction of adactyly for 4th and 5th toes: the study of foot pressure.

Analysis of foot pressures in cases of reconstructed adactyly of the lateral toes is presented. Two cases with adactyly of the 4th and 5th toes in which new toes were created by cross-knee tubed pedicle flap were chosen and foot pressures of both the operated foot and the contralateral normal foot were measured postoperatively. The results did not indicate any functional disturbance after this method of reconstruction.


Different ability in PC12 clones to recover from MMC toxicity following NGF treatment.

PC12 cells were cloned, and from their ability to form neurite-like processes 3 clones were selected: NGF-highly sensitive clone (HS), -moderately sensitive clone (MS), and -insensitive clone (IS). These clones were tested for the presence of specific NGF receptors by measuring the binding of 125I-labeled NGF. All 3 clones were capable of binding NGF, but the HS clone had more NGF receptors than the MS and IS clones. The effects of methyl mercuric chloride (MMC) and/or nerve growth factor (NGF) on these clones were tested. The HS clone was a little more susceptible to MMC than the MS and IS clones. When NGF was added to the culture medium in addition to MMC, cell recovery was observed. The tendency toward recovery was more prominent in the HS clone than in the IS one. Recovery in the MS clone was intermediate. These results suggest that NGF treatment can contribute to functional recovery of PC12 cloned cells from the cytotoxic effects of MMC depending on their ability to react to NGF.


Warfarin-induced complete bilateral breast necrosis.

Plastic surgeons are routinely consulted about the care of extended cutaneous necrosis. We present an unusual case of complete bilateral breast necrosis and review of the literature of warfarin-induced necrosis to inform plastic surgeons of new advances in the physiopathology of this entity. Warfarin-induced necrosis seems to be produced by an imbalance between circulating clotting factors and blood anticoagulation factors.


Tetanus following human bite.

We present an unusual case of tetanus which followed a human bite. The patient, a 43-year-old woman, developed tetanus within 4 days of sustaining a human bite. She died 6 days after admission despite aggressive management in the intensive care unit.


Influence of trigeminal nasal afferents on bulbar respiratory neuronal activity.

This study examined the influence of nasal trigeminal afferents, the anterior ethmoidal nerve (AEN) and posterior nasal nerves (PNN) on the spike discharges of respiratory-related neurons recorded in the ventral respiratory group (VRG) (2.6-3.5 mm lateral to the midline, from 1 mm rostral to 3 mm caudal to the obex and at depth of 2-4 mm below the dorsal surface). Electrical stimulations to the AEN and PNN were administered to 10 pentobarbital anaesthetized cats and to 8 ketamine anaesthetized, vagotomized, curarized and ventilated cats. Single shock stimulations of either nerve evoked transient and total inhibition of inspiratory activities. Expiratory-related neurons of the VRG presented three patterns of activity in response to stimulation:excitation, inhibition or inhibition followed by excitation. More generally, expiratory units are activated with a short latency. In the course of repetitive stimulation of the AEN and PNN we observed a prolongation of the spontaneous inspiratory discharge which presented transient, short inhibition in response to each shock. Most expiratory units presented a short activation which was synchronous with the transient inhibition of inspiratory activities. When repetitive stimulation provoked a sneeze-like response, we observed a progressive increase in the duration of transient inspiratory inhibition first, associated with a progressive reinforcement of transient expiratory activation. Secondarily, just before the expiratory thrust, we noted a stronger inhibition of the inspiratory activity which preceded a high-frequency (400 Hz) expiratory discharge. Nasal afferents exert a forceful excitatory effect on bulbospinal (BS) and non-bulbospinal-non-vagal (NBS-NV) expiratory cells of the VRG. The effects due to vagotomy and curarization are discussed.


Thymopoietin, a thymic polypeptide, prevents nicotinic agonist-induced morphological changes in neonatal muscle cells in culture.

Thymopoietin, a polypeptide hormone isolated from thymus and involved in immune function, potently inhibited [125I]alpha-bungarotoxin binding to neonatal muscle cells in culture (IC50 = 3.8 nM) and blocked carbachol-stimulated 22Na uptake with an IC50 of 1.9 +/- 0.2 nM and 23 +/- 7 nM at a half-maximal and maximal concentration of carbachol, respectively. Studies were subsequently done to evaluate potential long-term functional consequences of this interaction of thymopoietin at the nicotinic receptor. Exposure (1-3 days) of neonatal muscle cells in culture to nicotine (3 x 10(-6) M) or carbachol (1 x 10(-6) M) resulted in a decline in myotube branching and a decrease in myotube length. Thymopoietin did not appreciably alter myotube morphology on its own; however, it prevented the effects of nicotine and carbachol on muscle cell morphology at concentrations (1-10 nM) which corresponded well to those with which thymopoietin interacted at the receptor. The action of alpha-bungarotoxin on the myotubes was very similar to that of thymopoietin. These studies suggest that the endogenously occurring polypeptide, thymopoietin, has the potential to modulate muscle cell morphology through an interaction at the nicotinic receptor.


Mechanically evoked perioral reflexes in infants.

Mechanically evoked activity in the superior and inferior segments of the orbicularis oris muscle was sampled in several young infants using a specially designed position-servo linear motor and a pacifier instrumented with eight miniature EMG electrodes. Unilateral stimulation of lip vermilion resulted in short latency, bilateral activation of the upper and lower lip recording sites. The ontogenesis of facial reflex sensitivity to mechanical inputs is discussed in relation to the acquisition of motor skills, including speech and smiling.


Cell swelling induced by medium hyposmolarity or isosmolar urea stimulates gonadotropin-releasing hormone secretion from perifused rat median eminence.

Medium hyposmolarity between 10 and 50% and isotonic urea between 22.5 and 90 mM induced a dose-dependent burst of gonadotropin-releasing hormone (GnRH) secretion from perifused median eminence tissue which was maximal at 2-3 min and returned to near baseline by 5 min in spite of continued exposure to the stimulus. If Ca(2+)-free medium was used, osmotic stimulation of secretion was increased or unchanged, but secretion induced by 30 mM K+ was markedly reduced. Our data indicate that cell swelling induced by medium hyposmolarity or permeant molecules stimulates GnRH secretion from median eminence cells or cell processes as it does secretion from normal endocrine cells containing hormone stored in intracellular vesicles. In both, Ca2+ influx is not required or has a negative modulating influence on cell swelling-induced secretion.


Cortical norepinephrine release elicited in situ by N-methyl-D-aspartate (NMDA) receptor stimulation: a microdialysis study.

Norepinephrine (NE) release measured by microdialysis from probes positioned in the prefrontal cortex of anesthetized rats was increased when N-methyl-D-aspartate (NMDA) was contained in the microdialysis medium. NE release increased by a factor of 3.6 compared to prior baseline levels when 1 mM NMDA was applied for 30 min. This increase was largely reversible, and when a second stimulation was applied using aconitine (0.3 mM, 30 min), which acts on voltage-sensitive sodium channels, a second evoked release of NE was observed, of a similar magnitude as that evoked by NMDA. Dizocilpine (300 nM), which blocks cation channels associated with NMDA receptors, prevented the NMDA-elicited NE increase but not the aconitine-elicited increase.


Somatic afferent fibers which continuously discharge after being isolated from their receptors.

A previous study in our laboratory has shown that some afferent axons produce prolonged discharges after the axons have been completely isolated. We have attempted to identify the type of afferent fibers displaying such activity. Single unit activity was recorded from a filament dissected from the distal stump of the cut sural or plantar nerve of an anesthetized rat. After thorough identification of the receptor type, the nerve was cut at a site between the recording electrode and the receptive field, completely isolating the fiber being recorded. Unit activity was recorded up to 1 h after sectioning the nerve. Upon sectioning the nerve, most units showed brief injury discharges lasting only a few seconds. However, 21 of 70 units exhibited prolonged discharges lasting at least 30 min after having been isolated from their receptors. These 21 units included 8 slowly adapting type II cutaneous mechanoreceptors, 3 Pacinian corpuscles and 10 muscle spindle afferent units. These results suggest that prolonged injury discharges can be produced in the axons of the slowly adapting type II cutaneous mechanoreceptors, Pacinian corpuscles, and muscle spindle afferents. This phenomenon may have important clinical and experimental consequences.


Human fetal myelinated organotypic cultures.

We have previously reported the establishment of organotypic cultures derived from human fetal brain tissue. Although these cultures permit the testing of multiple hypotheses about normal human neurodevelopment and neuropathologic conditions, they have the limitation of not being myelinated and therefore preclude the study of questions related to myelinogenesis and diseases of myelin. In the current communication, we describe recent developments that allow us to overcome this limitation and permit the establishment of a myelinated organotypic culture model. Sections of dorsal column dissected from the lumbar spinal cord of human fetuses ranging in age 21-23 weeks of gestation were placed in culture. The explants were maintained for up to 12 weeks during which time they were characterized and shown to express a number of CNS cell-type-specific markers including glial fibrillary acidic protein (astrocytes), nerve growth factor receptor and neurofilament protein (neurons), CD68 (microglia), and myelin basic protein, HNK-1 and galactocerebroside (oligodendrocytes). In addition, lectin histochemistry using Ricinus communis agglutinin-1 detected microglia and endothelial cells. Upon explantation, abundant myelin was seen by electron microscopy in the cultures. Although during the culture period there was degradation of myelin, there was also evidence of maintenance of intact myelin sheaths around small caliber axons and de novo myelin synthesis. This model system may permit the further use of human organotypic cultures to investigate issues related to neurodevelopment and to pathologic conditions including those relevant to dysmyelination and demyelination.


Action of picolinic acid and structurally related pyridine carboxylic acids on quinolinic acid-induced cortical cholinergic damage.

Picolinic acid, a pyridine monocarboxylic acid derived from tryptophan metabolism by the kynurenine pathway, was shown to block cortical cholinergic neurotoxicity induced by quinolinic acid (QUIN), a pyridine dicarboxylic acid yielded by the same pathway. This study examined the specificity of the anti-toxic effect of picolinic acid by comparing its effect with several structurally related mono- and dicarboxylic acids, and by evaluating its potential to influence cholinergic neurotoxicity produced by kainic, ibotenic and quisqualic acid. Picolinic acid or related agents were injected alone or in combination with a fixed dose of QUIN into the right nucleus basalis magnocellularis (nbM) of rats anesthetized with halothane. Cholinergic neurotoxicity was assessed 7 days post injection by measuring choline acetyltransferase (ChAT) activity in the frontoparietal cortex on the injected and uninjected side. In picolinate experiments, the staining of nbM neurons by acetylcholinesterase (AChE) histochemistry was also examined. Focal injections of QUIN depleted cortical ChAT activity and staining of AChE in the nbM. Co-injection of picolinic acid with QUIN attenuated the decline in these two cholinergic neuron markers. Isonicotinate (4-pyridine monocarboxylate), but not nicotinate (3-pyridine monocarboxylate), significantly attenuated QUIN's effect on cortical ChAT activity. Among several dicarboxylic acids examined, only dipicolinate (2,6-pyridine dicarboxylate) showed activity. It produced a modest QUIN-like effect, but in co-injection experiments it attenuated the QUIN-induced decrease in cortical ChAT. When co-injected into the nbM with a neurotoxic dose of kainic, ibotenic or quisqualic acid which produced a neurotoxic response comparable to that of QUIN, picolinic acid attenuated kainic acid-induced neurotoxicity, but not ibotenate or quisqualate neurotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)


Potential use of DPCPX as probe for in vivo localization of brain A1 adenosine receptors.

The suitability of (3H)DPCPX (8-cyclopentyl-1,3-dipropylxanthine), a xanthine derivative, as an vivo probe for labelling adenosine A1 receptors was studied in rats. [3H]DPCPX (nM) penetrated largely into the brain (0.8% of the injected dose per gram of brain tissue 5 min after injection). Brain concentrations stayed at a plateau level from 5 to 15 min after the injection. The distribution in the different brain regions was heterogeneous with the highest amount of [3H]DPCPX in cerebellum and hippocampus and the lowest concentrations in hypothalamus and brain stem. Displacement (45-70% of total radioactivity) was obtained by the injection of 250 nM of cold DPCPX or cyclopentylxanthine, an analog of DPCPX. The ex vivo autoradiographic distribution of [3H]DPCPX was similar to the in vitro autoradiographic distribution of tritiated A1 adenosine receptor ligand as [3H]CHA. These results suggest the potential use of DPCPX for further in vivo investigation of A1 adenosine receptors with techniques such as positron emission tomography.


Cell surface extensions associated with overexpression of Alzheimer beta/A4 amyloid.

Deposition of beta/A4 amyloid in Alzheimer disease (AD) brain parenchyma and vasculature occurs by mechanisms that are currently undefined. Similarly the potential consequences of amyloid accumulation for disrupting cellular integrity have not been addressed in detail. To investigate the possible significance of amyloid deposits for cellular viability, PC12 cells were permanently transfected with DNA coding for the beta/A4-C terminal region of the amyloid precursor protein. The DNA represented 97 amino acids of the amyloid precursor protein of which 40 amino acids were derived from the beta/A4 region. Transfected clonal cell lines and controls were examined at both the light and electron microscopic levels for morphological abnormalities. beta/A4 amyloid accumulated in the cell membrane where the peptide was located at cellular processes resembling blebs and microvilli. These specialized structures at the cell surface were over-abundant in transfected cells that overexpressed the beta/A4 peptide but not in controls. Membranous processes may be involved in the delivery of the beta/A4 peptide to the external surface of the cell of origin and release into the extracellular space. Similar surface features of cells in the AD brain, should they occur, may indicate a role for membrane-associated processes in the pathophysiology of the disorder.


Serotonergic reinnervation of the hamster suprachiasmatic nucleus and intergeniculate leaflet without functional circadian rhythm recovery.

Intraventricular injections of the neurotoxin, 5,7-dihydroxytryptamine (DHT), were used to lesion hamster forebrain serotonin systems. The entrained circadian wheelrunning rhythm was studied for up to 20 weeks post-lesion as was the extent of reinnervation of nuclei regulating circadian rhythmicity. Reinnervation of the suprachiasmatic nucleus and intergeniculate leaflet by serotonergic fibers begins by 8 weeks and progresses to substantial, but not complete, levels by week 20. Four measures of the nocturnal activity phase of the circadian rhythm were rapidly modified by the lesions, but in contrast to the morphology, persisted unchanged during the entire 20 week test period. The circadian rhythm system of hamsters may be fundamentally different from other behavioral or neuroendocrine systems studied in rats with respect to its inability to recover from damage to its serotonergic innervation. Alternatively, the failure to demonstrate functional recovery may reflect a species difference or insufficient recovery time.


Effects of different rates of drying cassava root on its toxicity to broiler chicks.

1. The effects of drying cassava root at different rates on its composition and toxicity to broiler chicks were examined. Unpeeled roots from a high-cyanide cultivar of cassava were chipped and dried at 25 degrees C to a moisture content of below 100 g/kg over 24 h for fast-dried meal (FD) or 72 h for slow-dried meal (SD). The meals were incorporated at 250 and 500 g/kg into semi-synthetic diets which were fed to day-old broiler chicks as mash or pellets in separate experiments. 2. The two drying rates produced meals with similar concentrations of polyphenols, but different concentrations of cyanogens, the latter being 38 and 482 mg total cyanide/kg for SD and FD, respectively. The linamarin, acetonecyanohydrin or total cyanide content measurements of pelleted diets were highly correlated. 3. Growth rates of chicks fed on SD-based diets were significantly higher than those of chicks fed on FD-based diets. Compared with a control diet, weight gain of chicks fed on the 500 g FD/kg diet (containing 258 mg total cyanide/kg) was 77% lower, although performance also appeared to be reduced at 142 mg total cyanide/kg. 4. The ratio of water:food intake of chicks was higher in FD than in SD groups, and this was reflected in the high water content of excreta. There was increased bile excretion, the chloretic effect increasing with the cyanogen content of diet. Pancreas weights were lower in FD than in SD groups in experiment 1 (mash diets), but not in experiment 2 (pelleted diets), while there was a significant interaction between drying method and cassava inclusion rate on liver weight in experiment 2, but not in experiment 1. There were no effects on the mortality rate. 5. Pelleting of diets generated high temperatures, but did not significantly alter the cyanogen concentration or the growth of the chicks. 6. Thus, slower rates of drying cassava roots produce meals with lower cyanogen concentration that are, consequently, less toxic to broiler chicks. Cassava root meal of less than 40 mg total cyanide/kg can be fed to broiler chicks at 500 g/kg without any adverse effects.


Plasma oestrogen and triglyceride concentrations and reproductive characteristics of broiler chickens after ten generations of selection at seven weeks of age for high or low plasma very low density lipoprotein concentration.

1. Day old female chicks from two lines of broilers, selected for high or low plasma concentrations of very low density lipoproteins, were fed ad libitum or restricted until point of lay. All birds were fed ad libitum after laying an egg, and aspects of growth and reproduction were measured to 40 weeks of age. 2. Compared with lean line birds the growth rate of fat line females fed ad libitum declined from 16 weeks of age. 3. Mortality from apparently stress-related causes in ad libitum fed fat line females increased from 16 weeks of age and was 71% overall, compared with 26% in ad libitum fed lean line females. Mortality in the corresponding restricted birds was 20% and 7%, respectively. 4. Few fat line females fed ad libitum commenced lay and those which were restricted during rearing stopped laying after the initiation of ad libitum feeding. Egg productions in lean line birds fed ad libitum or restricted were similar. 5. Fat line females fed ad libitum had few yellow follicles and a high rate of atresia at first egg and between 37 and 39 weeks, as did restricted fat line birds between 37 and 39 weeks of age after being fed ad libitum. 6. Plasma concentrations of oestradiol-17 beta were 5-fold higher in fat compared with lean line females at 35 weeks of age. There was a similar large difference in concentrations of plasma triglyceride which reached 59 mg/ml in fat line females fed ad libitum.


Biological chick procedure to determine fluoride availability in sepiolite.

1. A modified fluoride (F) bioassay procedure based on the method of standard additions and using chicks was tested for the determination of F availability in sepiolite. Chicks were distributed between a control group fed on a basal diet and experimental groups fed on this diet supplemented with 100, 200 or 300 mg/kg F as sodium fluoride. A further group was fed on the basal diet plus 2 g/kg sepiolite. 2. Body weight gain and food consumption during a 60 or 90 d study were similar for all treatments. 3. Ileal digestibility of F from the basal diet or from the diet supplemented with 200 mg/kg F as sodium fluoride was higher (0.907) than for chicks fed on the sepiolite diet (0.152). 4. Increases in the F contents of tibia ash were linearly related to dietary F concentration as sodium fluoride. 5. F contents of tibiae from the sepiolite group (at 60 or 90 d of age) were plotted against tibia F concentrations from groups receiving additional sodium fluoride in the diet. A weighted regression was performed. The values obtained for the relative available F from sepiolite were 0.213 and 0.150, respectively, at 60 and 90 d of age.


Occurrence of intraportally-infused urea-15N in the urine of domestic fowl.

1. Measurements were made in situ to determine the occurrence of intraportally infused urea-15N in ureteral urine of the fowl. 2. Of the total amount of infused urea-15N, 15% was excreted intact into the urine (90% of urinary total 15N) whereas 9% remained unchanged in the blood (78% of blood non-protein-15N). 3. The proportions of non-protein-15N in the blood, liver and kidney were 12, 3 and 1%, respectively of the infused 15N. Protein-15N was 3% of that infused in blood and much less in liver and kidney. 4. About 1% of the infused 15N was observed in the urinary uric acid, and 3% of the infused 15N in non-protein N, other than urea, ammonia and glutamine amide N, of blood and liver. 5. No appreciable amounts of 15N were present in ammonia and glutamine amide N of blood, liver or kidney and in uric acid of liver or kidney. 6. The caecal contents contained about 1% of the infused 15N with 15% of this as ammonia-15N. 7. It is concluded that intraportal urea is mostly excreted unchanged into ureteral urine of the fowl.


Effect of dietary protein content on episodic growth hormone secretion and on heat production of male broiler chickens.

1. The effect of the crude protein content (200 and 150 g/kg) of isoenergetic diets on episodic growth hormone (GH) release and on heat production was investigated in male broiler chickens. 2. Decreasing the crude protein content of isoenergetic diets from 200 g/kg (HP diet) to 150 g/kg (LP diet) resulted in depressed body weight gain, impaired food conversion efficiency and increased abdominal fat deposition. 3. The pattern of growth hormone secretion was markedly affected by dietary treatment. Broiler chickens fed on the LP diet had higher overall mean, amplitude, baseline and peak frequency than the HP chickens. 4. The LP chickens produced more heat per unit of metabolic body weight than the HP chickens. 5. The hypothesis relating the pattern of GH secretion to protein conversion efficiency was corroborated.


Non-invasive determination of heart rate in newly hatched chicks.

1. Using a flexible piezoelectric probe, we detected non-invasively the cardiogenic precordial movements of domestic fowl chicks and measured heart rate (HR) daily over the first week after hatching (day 0) for comparison with previously measured embryonic HR. 2. HR of the hatchlings was much more variable than embryonic HR. The mean HR at a given age also varied among the 5 chicks measured. 3. The overall mean HR was 280 +/- 20 (SD, n = 5) bpm on day 0. This value was similar to the prepipping HR and lower than that of externally pipped embryos. It increased to 342 +/- 39 bpm 3 days later.


Composition, cortical structure and mechanical properties of chicken tibiotarsi: effect of growth rate.

1. Comparisons of tibial growth in slowly (X) and rapidly (F) growing chicks were carried out weekly until the birds weighed 500 g. 2. Bone volume and percentage of ash per dry weight increased with age and were similar at equal body weights between crossbreeds. In birds of the same age, the ratio of tibial dry weight to hydrated weight was greater in crossbreed X as compared with crossbreed F. Consequently, the tibial density and the mineral content per volume were higher, at equal body weights, in crossbreed X. 3. Cortical cross-sectional area was greater in crossbreed F at the different ages, but was similar in both crossbreeds at equal body weights. A peripheral active zone of greater porosity was predominantly characterised by radial fibrolamellar tissue in fast growing birds and covered a larger area in crossbreed F than in crossbreed X. 4. Biomechanical properties of the tibiotarsi were evaluated in a three-point flexure test. The area moment of inertia was equal at similar body weights in both crossbreeds, but the yield or maximal forces and stiffness of tibiotarsi were lower in the rapidly growing crossbreed F compared with crossbreed X. 5. It is concluded that an increased rate of growth is associated with a lower mineral density and higher porosity of the tibial cortices resulting in reduced bending resistance.


Variation in egg yolk cholesterol concentration between and within breeds of the domestic fowl.

1. The pattern of variation for egg yolk cholesterol concentration between 5 commercial egg layer lines and a cross of Gallus domesticus is described. 2. Yolk cholesterol concentration in the cross was lower than in the lines, and 6.7% lower than the midparent value. 3. It is proposed that the reduced yolk cholesterol concentration of the cross may be a consequence of heterosis, although sex-linkage and/or maternal effects cannot be discounted. 4. The difference between the cross and parental lines is consistent with a physiological relationship between yolk cholesterol concentration and rate of egg production, but not between yolk cholesterol concentration and yolk weight.


Determination of pyrimethamine and sulphadimethoxine residues in eggs by high performance liquid chromatography.

1. Laying hens were given food containing per kg diet: 1 mg pyrimethamine, 10 mg sulphadimethoxine (SDM) or 1 mg pyrimethamine with 10 mg SDM, for 14 days. Residues in the eggs were determined by high performance liquid chromatography. 2. Pyrimethamine was mainly found in yolk. Its concentration was slightly higher when it was given with SDM. 3. The concentrations of SDM in eggs were not different when it was given alone or in combination with pyrimethamine. 4. After withdrawal, pyrimethamine residues decreased below the detection limit (0.02 mg/kg) in the yolk after 11 to 12 d and in the albumen after 2 to 3 d. SDM in yolk fell below the detection limit (0.01 mg/kg) on day 7, whereas in albumen it was not detectable after 2 to 3 d.


[The contribution of overseas health and medical services in food and nutrition].

This article reminds the contribution of Health and Medical Services in overseas territories and other developing countries. Seconded to Health Services, Pasteur Institutes, other scientific research Organisations, and International Organisations (FAO, WHO), medical doctors and pharmacists, properly trained in nutrition, have studied under-nutrition and malnutrition, and their effects on the health of the populations and the economy of their countries. Later, in cooperation with all departments concerned, they have realised a number of applied programmes, aiming at a real improvement in the situation or even the eradication of nutritional deficiencies. However the article deals mainly with actions related to food production and distribution, from the establishment of a national food policy to agriculture planning and evaluation, including specific, applied nutrition programmes in agriculture development and supplementary feeding programmes.


[Pharmacokinetics and therapeutic monitoring of cyclosporine in liver transplant recipients].

Cyclosporine (CsA) has played a major role in the development of organ transplantation. However, its use in the prevention of liver graft rejection is somewhat delicate because the liver plays an essential role in the intestinal absorption, metabolism and excretion of CsA. Interindividual differences in CsA pharmacokinetics are large, and clearance can vary by a factor of 40 in liver transplant recipients. During CsA therapy, the intact molecule is assayed in whole blood by means of specific technique. The margin between immunosuppressive and nephrotoxic concentration is poorly defined. The interpretation of blood concentrations must take into account the mode of administration, associated drug therapy, the time since grafting, and pathological episodes. The recommend trough concentrations are 150-200 ng/ml during the first three months.


[Primary hyperparathyroidism. Results of a French multicenter study].

The "Association française de Chirurgie" asked to authors an update on primary hyperparathyroidism based on a retrospective multicentric study on 4883 patients operated on by 79 surgeons. Aim of this study was an update on clinic and biologic aspects, localizing studies, and therapeutic aspects with their results. There were 3418 females (70%) and 1465 males (30%) mean age 53 years (9 to 91 years): 3702 solitary adenomas (75.8%), 720 multiglandular lesions (14.7%) 92 multiple endocrine neoplasias (1.9%) and 86 carcinomas (1.8%). None lesion was found in 283 cases (5.8%). To day, diagnosis is most often made on fortuitous hypercalcemia. Localising studies showed sensibility less than 50%. Surgery was successful in 92.7%. Mortality occurred in 0.6%, hypoparathyroidism in 3.8%, laryngeal palsy in 1.5% and hematomas in 0.45%. In conclusion this study shows the changes regarding the diagnosis, the uselessness of localizing studies before first cervicotomy, and the good results of surgery. Autotransplantation and cryopreservation allow reducing of hypoparathyroidism.


[Deficiencies, disabilities and handicaps: taking responsibility for the young maladjusted child].

A handicap should not be confused with deficiency or incapacity. It is the resulting difference between an individual's competencies and the situation which is proposed to, or imposed to, him. Whatever the type of deficiency a child may have, and the subsequent incapacity, it is important to discern for therapy, the positive aspects of his personality as soon as possible in order to develop his chances for success and avoid set backs. Structures such as the Medical and Social Early Action Center (CAMSP), which we created in 1976 at the Medical Center in Versailles, allow personalized care. More than progress in reference to an often illusory norm, it is the search for talents, aptitudes and, in function of this, the acquisition of knowledge, which should be the educator's concern. An excess of legislation may unfortunately lead to the standardization of the means and goals.


[Three bacterial species associated with Lyme borreliosis. CLinical and diagnostic implications].

DNAs from various Borrelia associated with Lyme disease were reciprocally hybridized. This genomic taxonomy method showed that Lyme disease agent comprised three genomic species. Two species could be differentiated by phenotypic characters as major proteins molecular weights and monoclonal antibodies reactivity. Western-blot with sera from patients suffering from different clinical forms of Lyme disease: arthritis, meningoradiculitis and Acrodermatitis Chronicum Atrophicans showed that each of these evolutive forms was preferentially associated with one of the species, respectively: Borrelia burgdorferi sensu stricto, Borrelia garinii and Borrelia group VS 461. Furthermore, geographical repartition of these three species was heterogeneous. B. burgdorferi sensu stricto seems to be the only one present in the United States of America, whereas it coexists in Europe mainly with B. garinii in Western Europe and Borrelia group VS 461 in Northern Europe.


[Is thyroid cancer a severe cancer? (Prognostic study of 800 surgically-treated cases of which 143 nodular differentiated cancers were followed-up for more than 20 years)].

The prognosis of thyroid carcinoma has always been difficult to appreciate because this rather rare carcinoma is polymorph and subject to some very late recurrencies. For these reasons an acceptable prognostic evaluation is only possible with an important material and very long follow-up. From 800 patients operated by the author, 102 (13%) had an extra-capsular tumor, which means for all authors a very poor prognosis. Still two groups must be separated: the anaplastic extracapsular tumors (33/102) gave a very low life expectancy with 17% survival at 5 years and no patient surviving at 8 years. In contrast the differentiated extracapsular tumors, mainly papillary, gave an unexpected survival rate of 35% at 15 years. The more frequent nodular form of differentiated carcinoma (698/800 = 87%) has a much better prognosis, but his slow evolution needs a long follow-up observation. From 160 patients operated on before 1971, 143 (90%) could be all followed during 20 years or more. The over-all survival rate at the 20th year is 83% with 76% of patients free of any recurrence. The analysis of several factors showed that the extension of the primitive operation (lobectomy or total thyroidectomy) does not influence the long term results. More reliable prognostic factors are the degree of histologic differentiation of the tumor, and the age of the patient. Finally, in spite of an excellent overall long-term prognosis, three very late recurrencies were observed in the group of 143 patients followed more than 20 years, respectively 21, 22 and 31 years after the first operation. This makes impossible the certitude of definitive cure of any thyroid cancer.


[Ethical and social problems posed by organ transplantation].

Organ transplantation more than a scientific fact is now a social fact. Since the first organ transplantations in France, forty years ago, medicine demonstrated its ability to perform the operation and to obtain (what was more difficult) the tolerance of the graft but medicine so far remains unable to give the material: organs. These organs are given by the donor's relatives when the kidney is concerned and when it is a donation from a living person. But such donation remain strictly limited in our country (less then 5% of the kidney transplantations) due to the risk of moral pressure and commercialization. More often and for the other organs (liver, heart, lung) a the donation is obtained after death, a special and dramatic death: the brain death. The nowadays spectacular results of organ transplantation 70 to 80% survival rate at 10 years with a complete rehabilitation gave a considerable increase on the demand. Unfortunately organ transplantation is the victim of its success, the number of donor's organ being insufficient to satisfy the needs. So in December 1990, 6,055 patients were on the waiting list and only 3,772 (56%) were transplanted. In December 1991, 6,334 patients were on the waiting list and may be only 4,000 could be transplanted. So the difference between the needs and the possibilities is increasing each year with for consequences, the death of 10% of the waiting patients and, for those who could be transplanted, a considerable increase in the waiting period responsible for slow deterioration of their status and less chances of success. The reason of the lack of organs is not due to the lack of brain deaths which are unfortunately too numerous, but to the impossibilities of organ retrieval due to: too advanced age or the presence of a transmissible disease of the donor, lack of medical means in some intensive care units, and family refusal. This refusal is easily understood and due to the very peculiar conditions in which the donation is required: the unexpected death of a loved parent and such a death with some life appearance. To avoid the increasing number of such refusal two actions are possible. One is the modification of the law. The French law is the Caillavet law which requires for organ retrieval, the written permission of the parents for a minor, or for an adult the absence of refusal expressed during his or her life.(ABSTRACT TRUNCATED AT 400 WORDS)


Modelling of the qualitative discrimination of odours in the first two layers of olfactory system by Jutten and Hérault algorithm.

The olfactory system discriminates many different odours although membrane receptors, and neuroreceptors that bear them, are only broadly tuned to volatile molecules. We investigated how mixed and redundant information carried by neuroreceptors could be efficiently coded by output neurons in the second neuronal layer in the brain. We showed that a good discrimination is yielded if neuroreceptors that terminate on the same output neuron belong to several types, if these types are in different proportions for each output neuron, and if each output neuron exerts an action on all others so that their independence is maximized, according to the Jutten and Hérault algorithm for separating linear mixtures of independent sources. The proposed model details the computations made by neurons and leads to a better understanding of several observed properties of the olfactory system, among which the inhibitory actions of local neurons of the second layer and the identifiability of insect glomeruli.


Peptide binding to MHC class I proteins measured with a novel fluorescent technique.

An N-dansylated peptide derived from the Plasmodium berghei circumsporozoite protein (PbCS 253-260) bound in an allele-specific manner to a single-chain Kd molecule (SC-Kd), and its binding resulted in significant fluorescent enhancement. The binding kinetics of unlabelled peptides could be determined by pre-incubating dansylated PbCS with a concentrated suspension of SC-Kd, and then diluting this mixture in the presence of unmodified peptide. The time-dependence of the ensuing fluorescence decrease could be fitted to a single-exponential, which gave an association rate constant of 77 M-1s-1 for unlabelled PbCS.


[Changes in heart genome expression in hypertensive diseases].

Chronic increases in haemodynamic load modify the expression of cardiac genes, leading to cardiac hypertrophy and a new phenotype. As an example, changes in the expression of the genes encoding the main contractile proteins, the isomyosin heavy chains, have been associated with modifications of the physiological properties of cardiac muscle. The cellular and molecular mechanisms which either do or do not initiate and maintain these changes in cardiac genomic expression remain to be elucidated. Using in situ hybridization we show that mRNAs encoding a cellular form of fibronectin (c-FN), a protein of the basal membrane which is not or poorly expressed in adult rat heart, are reexpressed as a result of severe hypertension with a similar time course than the beta-heavy chain of myosin (beta-MHC), also mostly expressed in fetal heart. The accumulation of the c-FN mRNAs was found in the wall of coronary arteries whilst that of the beta-MHC mRNAs occurred in the myocytes at the border zone of these arteries. Thus a high pressure in the arteries could be the trigger inducing the synthesis of factors which could, through a gradient, modulate the phenotype of both the smooth muscle cells of the media and the cardiocytes. Besides, using a model of cultured adult rat cardiocytes, we show that the differential expression of the MHC isoforms is dependent on the beta-adrenergic stimulation but that the regulation depends on the stage of development of the cells and differs for the alpha and beta MHC. These 2 complementary approaches for identifying the molecular mechanisms that control cardiac muscle growth should help for understanding cardiac adaptation triggered by haemodynamic overload, such as arterial hypertension as well as cardiac failure.


[Platelets and aging].

Platelets seem involved in pathogenesis of atherosclerosis and Alzheimer disease which frequency increases with population ageing. Platelet hyperactivation may contribute to atherosclerosis by release of factors, which increase fibroblast and smooth muscle cell proliferation and perhaps lipid deposition. Many studies evidenced an increased platelet activation with ageing concomitantly to an increase of some coagulation factors, and an impaired response of endothelial cells leading to a prethrombotic state and facilitating the occurrence of atherosclerosis. On the other hand, in Alzheimer disease, a deposit of amyloid beta protein responsible for vascular and neuronal damage was evidenced. Platelet activation is responsible for the release of an amyloid beta protein precursor (the protease nexin 2). An increased platelet activation as demonstrated with aging, may thus explained the increased occurrence of Alzheimer disease.


[Platelet plasma membrane: characterization of the serotonin transporter].

After treatment of human platelets by a sulfhydryl-dependent bacterial protein cytolysin, a glycoprotein was reproducibly purified by a one-step affinity chromatography using 6-fluorotryptamine as ligand and elution by serotonin (5-HT), cyanoimipramine, citalopram, or a Na(+)-free buffer. The purified fraction migrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis as a single band with an apparent molecular mass of 68 kDa. The purified glycoprotein bound the 5-HT uptake blockers 3H-paroxetine, 3H-cyanoimipramine, and 3H-citalopram with Kds similar to the ones observed for intact human platelets. No binding was detected with 3H-hydroxytetrabenazine, 3H-ouabain, 3H-gamma aminobutyric acid or 3H-BTCP, the respective markers of the granular monoamine transporter, the plasma membrane Na+, K(+)-ATPase, the gamma aminobutyric acid and dopamine carriers. The purified 68-kDa glycoprotein is therefore likely to correspond at least to the paroxetine and imipramine binding domains of the 5-HT transporter located at the human platelet plasma membrane. Finally a 68-kDa protein was purified in the same conditions from the human megakaryocytic cell line Dami and to a lesser extent from the human megakaryoblastic cell line MEG-01 but not from the human erythroleukaemic cell line HEL.


[Demonstration of a protector effect of interleukin-1 against hematologic toxicity of azidothymidine (AZT)].

3'-azido-3'-deoxythymidine (Azidothymidine or AZT) has attained wide critical utility in the treatment of acquired immunodeficiency syndrome (AIDS). Unfortunately, treatment with AZT is associated with the development of severe hematopoietic toxicity. The AZT sensitivity of marrow progenitors was different with an IC 50 of 10(-8) M and 10(-6) M for respectively BFU-E and CFU-GM/GEMM. Data reported here show that recombinant human interleukin-1 alpha (IL-1 alpha), a pleiotropic cytokine, was demonstrated to be efficient to protect normal human as well as murine hematopoietic progenitors (CFU-GM, CFU-GEMM and BFU-E) from the toxic effect of AZT. The maximal effect was observed with 30 U/ml (Human cells) or 100 U/ml (murine cells) IL-1 alpha for BFU-E and CFU-GM/GEMM, with a marked effect at 1 U/ml. The results demonstrate that marrow progenitors respond differently to AZT and point out the potential efficacy of IL-1 alpha to enhance the proliferation of hematopoietic stem cells treated with growth factors (IL-3, erythropoietin) and to minimize the hematopoietic toxicity associated with AZT treatment.


[Participation of cytokines and immune sera to the cytoadherence of erythrocytes infected by Plasmodium falciparum on the endothelial cells in culture].

In vitro binding capacity of erythrocytes infected with P. falciparum and the modulation of cytoadherence on human endothelial cells by cytokines and sera from semi immune subjects in relation to cytoadherence were studied. Tumor necrosis factor and interleukin-3, alone or in combination with granulocyte macrophage-colony stimulating factor, enhanced in vitro cytoadherence. Contrary to pooled immune sera, patients' sera obtained during acute or convalescent phase did not reverse nor inhibit in vitro cytoadherence.


[Study of possible influence of mixed lymphocyte reaction on experimental models used in biological dosimetry].

The study aimed to investigate whether "mixed lymphocyte reactions" could interfere with the results of experiments in which irradiated blood from one person is mixed with non-irradiated blood from another. This experimental model had been designed to simulate, in vitro, non-homogeneous in vivo exposure such as could occur after accidents with ionizing radiation. The results show that the experimental models gives valid results for donors with related blood characteristics.


[Free radicals, lipid peroxidation and muscular ischemia].

The role of oxygen free radicals in ischemia and reperfusion injury of skeletal muscle has not been well defined, partly because of the relative resistance of this tissue to normothermic ischemia. Under normal conditions small quantities of oxygen free radicals are produced but they are quenched by intracellular free radical scavenging enzymes (superoxide dismutase, catalase and glutathione peroxidase) or alpha-tocopherol. The increase in malondialdehyde suggests increased lipid peroxidation initiated by free radical reactions. Lipid peroxidation is potentially a very damaging process to the organized structure and function of membranes. The results of recent studies indicate that: a) oxygen free-radicals mediates, at least in part, the increased microvascular permeability produced by reoxygenation, b) free radical scavengers can reduce skeletal muscle necrosis occurring after prolonged ischemia. Additional evidence support the hypothesis of the interrelationship between ischemic tissue and inflammatory cells. So capillary plugging by granulocytes and oxygen free radical formation may contribute to the ischemic injury.


[Malondialdehyde production and erythrocyte membrane resistance to free radicals, in function of adequate or inadequate protein intake, associated with different oils (sunflower, soybean, coconut, salmon)].

Requirements in polyunsaturated fatty acids (PUFA) of series n-3 and n-6 may be amplified and their metabolism, transport, and utilization may be impaired in the long term, by protein depletion. The aim of this study was to evaluate, in young rats, malondialdehyde (MDA) production and erythrocyte membrane antioxidative defense, when they were fed balanced (20% casein) or depleted (2% casein) protein diet associated with various oils (sunflower, soybean, coconut or salmon). Over a short period (28 days), eight groups of 10 male Wistar rats were fed eight different diets: TOC (20% casein + 5% sunflower oil), TOd (2% casein + 5% soybean oil), SOC (20% casein + 5% soybean oil), SOd (2% casein + 5% soybean oil), COC (20% casein + 5% coconut oil), COd (2% casein + 5% coconut oil), SAC (20% casein + 5% salmon oil), SAd (2% casein + 5% salmon oil). Blood was removed, MDA was assessed in plasma (reaction with thiobarbituric acid). Washed erythrocytes were subjected to organic free radical generator (Kit KGRL 400 Spiral R.D., Couternon, 21560 France). The haemoglobin released was analysed by spectrophotometry. The total anti-radical defense status was expressed as the length of time to reach 50% hemolysis (T 50% in min). Plasma of deficient groups (2% casein) exhibited low concentrations of protein, particularly with coconut and salmon oils; phospholipid and total cholesterol, excepted with diet containing coconut oil; triacylglycerol; and VLDL. Malondialdehyde. In groups fed balanced protein diets, the lowest values were obtained with salmon and coconut oils. MDA contents of groups TOd, COd and SAd were higher than those of their respective control groups, but significantly only in group COd. Antiradical defense status. Total anti-radical defence status in erythrocytes was not modified in the short term by balanced or depleted protein diets which ever oil was used, despite deep changes in fatty acid composition of membrane phospholipids. In particular, phospholipid contents in eicosapentaenoic, docosahexaenoic acids were greatly enhanced by the consumption of salmon oil compared to the values obtained with coconut oil.


Regulation of intestinal glucose transport.

The small intestine is capable of adapting nutrient transport in response to numerous stimuli. This review examines several possible mechanisms involved in intestinal adaptation. In some cases, the enhancement of transport is nonspecific, that is, the absorption of many nutrients is affected. Usually, increased transport capacity in these instances can be attributed to an increase in intestinal surface area. Alternatively, some conditions induce specific regulation at the level of the enterocyte that affects the transport of a particular nutrient. Since the absorption of glucose from the intestine is so well characterized, it serves as a useful model for this type of intestinal adaptation. Four potential sites for the specific regulation of glucose transport have been described, and each is implicated in different situations. First, mechanisms at the brush-border membrane of the enterocyte are believed to be involved in the upregulation of glucose transport that occurs in streptozotocin-induced diabetes mellitus and alterations in dietary carbohydrate levels. Also, factors that increase the sodium gradient across the enterocyte may increase the rate of glucose transport. It has been suggested that an increase in activity of the basolaterally located Na(+)-K+ ATPase could be responsible for this phenomena. The rapid increase in glucose uptake seen in hyperglycemia seems to be mediated by an increase in both the number and activity of glucose carriers located at the basolateral membrane. More recently, it was demonstrated that mechanisms at the basolateral membrane also play a role in the chronic increase in glucose transport observed when dietary carbohydrate levels are increased. Finally, alterations in tight-junction permeability enhance glucose absorption from the small intestine.(ABSTRACT TRUNCATED AT 250 WORDS)


Application of alkaline unwinding assay for detection of mutagen-induced DNA strand breaks.

The frequency of single-strand breaks in parental DNA and gaps in nascent DNA in various cells exposed to methyl methanesulfonate (MMS) or methylnitrosourea (MNU) was investigated by alkaline unwinding assay using two types of alkaline lysis conditions, 22 degrees C lysis versus 0 degrees C lysis. The DNA damage induced by MMS and MNU is considered to be characteristic of lesions produced in DNA by alkylating agents. The aim of our research project was to adjust this method to be able to detect the greatest number of DNA lesions induced by alkylating agents in parental DNA of different mammalian cells. In our experiments we used human cell lines EUE, GM637 and XP12, Chinese hamster V79 cells, and Syrian hamster embryo cells. The higher level of strand interruptions was detected under conditions of lysis of cells at 22 degrees C. Probably the level of strand interruptions found after the lysis of cells at 22 degrees C correlates with the increased number of disrupted alkali-labile sites of DNA. It is remarkable that the different lysis conditions did not influence the number of gaps detected in nascent DNA of alkylated cells. Comparing induction of breaks and gaps in radiolabelled strands of parental and daughter DNA under different lysis conditions, we succeeded in defining the optimum conditions for detection of alkali-labile sites of parental DNA.


Evidence for endothelium-dependent and endothelium-independent vasodilation in human skin flaps.

Acetylcholine (ACh) and nitroglycerin (NTG) were used as probes to study endothelium-dependent and endothelium-independent vascular relaxation in isolated perfused transverse paraumbilical human skin flaps. It was observed that ACh (10(-6) M) significantly (p < 0.05) decreased the vascular resistance and increased dermal capillary perfusion (assessed by surface fluorometry) in norepinephrine (NE, 10(-6) M) preconstricted skin flaps, despite the presence of a cyclooxygenase inhibitor (indomethacin, 3 x 10(-5) M) and a beta-adrenergic receptor antagonist (propranolol, 10(-6) M). The ability of ACh to induce vascular relaxation in NE-preconstricted skin flaps was lost after damaging the vascular endothelial lining with saponin perfusion (100 mg.L-1, 5 min). In contrast, NTG (10(-6) M) induced vascular relaxation to a similar extent before and after saponin treatment. In a separate study, ACh was seen to induce vascular relaxation in a concentration-dependent manner in skin flaps preconstricted with NE (10(-6) M). This vascular relaxation effect of ACh over the dose range of 10(-9)-10(-5) M was significantly (p < 0.01) inhibited in the presence of N omega-nitro-L-arginine (10(-5) M), a nitric oxide (NO) synthesis inhibitor. These observations were taken to indicate the presence of endothelium-dependent and endothelium-independent vascular relaxation in human skin flaps and that the ACh-induced endothelium-dependent relaxation is probably mediated by NO. The importance of impairment of endothelium-dependent relaxation in the pathogenesis of skin flap ischemia, and the potential use of topical nitrovasodilators or NO donors for prevention and (or) treatment of skin flap ischemia were also discussed.


Abnormal magnesium metabolism in two rat models of genetic hypertension.

Magnesium concentrations in erythrocyte ghosts and arterial tissue of male, spontaneously hypertensive rats (SHR) were significantly less than in these tissues of male normotensive controls (Wistar-Kyoto; WKY) of the same age, which were also fed rat chow and tap water. The magnesium concentration in SHR erythrocyte ghosts was increased to the control value by incubating SHR erythrocytes with WKY blood plasma; SHR plasma did not affect the magnesium concentration in WKY erythrocyte ghosts. The magnesium concentrations in erythrocyte ghosts, aortas, and mesenteric arteries from female salt-sensitive (SS/JR) and salt-resistant (SR/JR) Dahl-derived rats, both maintained ad libitum on laboratory rat chow and either tap water or 0.9% NaCl, were not different but were significantly less than those of Sprague-Dawley rats considered as controls. While the ingestion of 0.9% NaCl had no effect on the magnesium concentrations measured in these animals, it caused the salt-sensitive rats to become severely hypertensive. It is evident from these observations that the decreased binding of magnesium to the plasma membrane of cells may be an inheritable metabolic defect that may be associated with the development of hypertension. However, in those instances of hypertension in which this defect occurs, it appears to be a contributing cause of the hypertension; by itself the defect is not a cause of hypertension.


An evaluation of three pesticides: piritione, supercypermethrin and metolachlor in transformation bioassays of BHK21 and hamster embryo cells.

In a study of potential carcinogenicity of pesticides, Piritione, metolachlor (in the form of Dual and VUCHT 524) and Supercypermethrin (in the form of Supercypermethrin EC and Supercypermethrin TP) were assayed for induction of anchorage independent growth of BHK21 cells and morphological transformation of Syrian hamster embryo cells. The activity of these substances in both transformation assays was compared to the activity of the direct-acting ultimate carcinogen N-methyl-N-nitrosourea. In comparison to the very strong transforming activity of N-methyl-N-nitrosourea all pesticides tested with or without S9 fraction manifested a very weak, weak, medium or strong effect. The ability to induce anchorage independent growth was graded as follows: Dual < Supercypermethrin EC < Supercypermethrin TP < or = Piritione < VUCHT 524. Results of Syrian hamster embryo cell transformation assay were very similar to the BKH21 transformation assay. VUCHT 524 strongly induced transformation whereas Dual was inactive. Piritione and Supecypermethrin EC and Supercypermethrin TP elicited a slight but significant positive response.


Effects of K+ on the twitch and tetanic contraction in the sartorius muscle of the frog, Rana pipiens. Implication for fatigue in vivo.

The effects of increasing the extracellular K+ concentration on the capacity to generate action potentials and to contract were tested on unfatigued muscle fibers isolated from frog sartorius muscle. The goal of this study was to investigate further the role of K+ in muscle fatigue by testing whether an increased extracellular K+ concentration in unfatigued muscle fibers causes a decrease in force similar to the decrease observed during fatigue. Resting and action potentials were measured with conventional microelectrodes. Twitch and tetanic force was elicited by field stimulation. At pHo (extracellular pH) 7.8 and 3 mmol K+.L-1 (control), the mean resting potential was -86.6 +/- 1.7 mV (mean +/- SEM) and the mean overshoot of the action potential was 5.6 +/- 2.5 mV. An increased K+ concentration from 3 to 8.0 mmol.L-1 depolarized the sarcolemma to -72.2 +/- 1.4 mV, abolished the overshoot as the peak potential during an action potential was -12.0 +/- 3.9 mV, potentiated the twitch force by 48.0 +/- 5.7%, but did not affect the tetanic force (maximum force) and the ability to maintain a constant force during the plateau phase of a tetanus. An increase to 10 mmol K+.L-1 depolarized the sarcolemma to -70.1 +/- 1.7 mV and caused large decreases in twitch (31.6 +/- 26.1%) and tetanic (74.6 +/- 12.1%) force. Between 3 and 9 mmol K+.L-1, the effects of K+ at pHo 7.2 (a pHo mimicking the change in interstitial pH during fatigue) and 6.4 (a pHo known to inhibit force recovery following fatigue) on resting and action potentials as well as on the twitch and tetanic force were similar to those at pHo 7.8. Above 9 mmol K+.L-1 significant differences were found in the effect of K+ between pHo 7.8 and 7.2 or 6.4. In general, the decrease in peak action potential and twitch and tetanic force occurred at higher K+ concentrations as the pHo was more acidic. The results obtained in this study do not support the hypothesis that an accumulation of K+ at the surface of the sarcolemma is sufficiently large to suppress force development during fatigue. The possibility that the K+ concentration in the T tubules reaches the critical K+ concentration necessary to cause a failure of the excitation-contraction coupling mechanism is discussed.


The hen's fertile egg screening test (HEST): a comparison between the acute toxicity for chick embryos and rodents of 20 drugs.

The possibilities of using developing chick embryos for evaluating drug activities and toxicities were studied by determining LD50 values for 20 drugs with 14 different pharmacological activities. Fifteen-day old chick embryos received drugs through the air cell and deaths were measured at 48 hr after the treatments. The LD50 values were determined and compared to the i.v., i.p., s.c. and p.o. values from mice listed in the Registry of Toxic Effects of Chemical Substance. The systemic toxicity of 15-day-old chick embryos to drugs were similar to those of mice with the following exceptions. The chick embryos seemed to be more sensitive than mice to antineoplastic or antibiotic agents such as actinomycin D and doxorubicin, whereas, LD50 values of cholinergic and cholinergic blocking drugs by this method were 10 to 20 fold of LD50 (i.v.) of mice. These observations are important for applying the hen's fertile screening test (HEST) to the determination of drug activities other than that of embryo toxicity or teratogenic activity.


Testosterone metabolism in an in vitro skin model.

The metabolic activity of skin is important in penetration of topically applied compounds. Currently, animal or cadaver skin is used to evaluate the relationship between metabolism and penetration. In the present study, testosterone metabolism and penetration in a three-dimensional human skin model consisting of keratinocytes and fibroblasts derived from neonatal foreskins was characterized. Pieces of the model were placed on tissue culture inserts with HEPES-buffered medium on the dermal side. Penetration of [3H]testosterone was faster at 32 degrees C than 4 degrees C suggesting that metabolism affected penetration. To evaluate this metabolism, [3H]testosterone was applied to the stratum corneum side of the skin model. Radiolabeled metabolites released into the medium after incubation were separated by HPTLC and analyzed by autoradiography. This skin model metabolized [3H]testosterone to both more polar and non-polar compounds which were similar to metabolites of neonatal foreskins. The appearance of non-polar compounds was earlier than the appearance of polar compounds. Both dermal fibroblasts and differentiated epidermal keratinocytes contributed to the metabolism of testosterone. Two testosterone metabolites, dihydrotestosterone and androstane-3, 17 diol, were reduced by addition of the cytochrome P-450 inhibitor metyrapone and were only produced by the keratinocytes. In conclusion, this model is a reproducible source of metabolically active skin and therefore a good alternative to animal or cadaver skin for evaluation of the contribution of metabolism to penetration.


Brush border membrane proteins in experimental Fanconi's syndrome induced by 4-pentenoate and maleate.

Fanconi's syndrome was investigated using brush border membrane (BBM) vesicles isolated from dog kidney. Sodium-dependent uptake of glucose, phosphate, and amino acids and protein phosphorylation were studied in BBM isolated from normal and from 4-pentenoate- and maleate-treated animals. The time course of D-glucose and phosphate uptake, in BBM vesicles, remained unchanged, indicating that both treatments had no effect on carrier properties, and that permeabilities to these substrates and to sodium were not modified. Furthermore, sodium-dependent transport of alanine, phenylalanine, proline, glycine, and glutamate into vesicles remained unaltered by either treatment. 4-Pentenoate treatment caused modifications of the phosphorylation pattern of BBM proteins: the phosphorylation of two proteins (61 and 74 kDa) was increased and that of two others (48 and 53 kDa) was decreased. Maleate treatment caused an increase in the phosphorylation for the same 61-kDa protein, which was also affected by 4-pentenoate treatment, suggesting that phosphorylation of this protein could be related to a mechanism involved in both 4-pentenoate- and maleate-induced Fanconi's syndrome. These changes were also observed in the presence of sodium fluoride and L-bromotetramisole, indicating that the modification of phosphorylation was not due to a difference in phosphatase activities. These results suggest that Fanconi's syndrome induced by 4-pentenoate or maleate is not caused by an inhibition of BBM Na(+)-dependent transport systems. Our results also suggest that protein phosphorylation may play an important role in the molecular defect involved in Fanconi's syndrome.


Attempts to use the HPRT-assay as an automated short-term monitor for an acute exposure to mutagens.

Attempts have been made to use the hypoxanthine-guanine-phospho-ribosyl-transferase-assay as a method for automated screening of agent-induced phenotypic variants of human peripheral lymphocytes reflecting 6-thioguanine resistance and assumed to indicate genotoxic action. Different protocols of the hypoxanthine-guanine-phospho-ribosyl-transferase-system were used in this study in order to investigate whether the system can be a candidate for a short-term test for a rapid and reliable identification of biological systems exposed to agents. The current protocols were based on: 1) fluoresceinated monoclonal antibodies against bromodeoxyuridine-DNA for labelling of 6-thioguanine-resistant human lymphocytes and direct flow-cytometric enumeration of bromodeoxyuridine-positive events and: 2) indirect flow-cytometric enrichment of 6-thioguanine-resistant cells labelled with 3H-thymidine followed by autoradiographic enumeration of positive events. Both the direct and the indirect enumeration method yielded similar results down to the range 10(-4) with respect to frequency of variants. For the less time-consuming direct enumeration method the resolution was limited due to non-specific binding of the antibody and false positives. It was, nevertheless, sufficient to score variants induced in vitro with the mutagens EMS, MMC and TT in the same range as e.g. that of cancer patients during and after chemotherapy or radiotherapy, or that of psoriasis patients during the after PUVA (8-methoxypsoralen and long range UV light)-therapy. We conclude that the direct enumeration protocol can be used for a rapid screening of so called outliers, but a more sensitive test, such as the more time-consuming enrichment protocol based on autoradiography, must be used in order to score variants in the range 10(-5)-10(-6).


Influence of chronic nadolol treatment on blood pressure and vascular changes in spontaneously hypertensive rats.

Chronic treatment of spontaneously hypertensive rats (SHR) and Kyoto-Wistar normotensive rats (WKY) with nadolol was carried out from gestation until 28 weeks of age. Nadolol treatment caused some lowering of blood pressure but did not prevent the development of hypertension or cardiac hypertrophy in the SHR, in spite of significant beta-blockade. The lumen of large mesenteric arteries from control SHR was smaller than from WKY, and nadolol treatment increased the lumen size in the SHR. An increased number of smooth muscle cell layers present in the control SHR as compared with WKY was reduced slightly by nadolol treatment. However, the changes produced by nadolol did not reach the levels of control and treated WKY. In the aorta, the incidence of polyploid smooth muscle cells was higher in the SHR than the WKY in the control group. Nadolol treatment reduced the percentage of polyploid cells in both SHR and WKY, so that the difference between these two groups of animals was eliminated in the treated groups. The tissue level of norepinephrine in the plasma, heart, mesenteric arteries, and adrenal glands in the SHR and WKY was not affected by the treatment. We suggest that the ineffectiveness of nadolol in preventing hypertension development may be due to its lack of effect in preventing primary changes in the resistance arteries, and that the development of polyploidy of smooth muscle cells may be mediated by beta-receptors.


Cadmium-2-acetylaminofluorene interaction in isolated rat hepatocytes.

Cadmium (Cd) is a non-essential, highly toxic heavy metal and a ubiquitous environmental contaminant. Evidence exists that Cd can affect parameters which are of great importance in the response towards xenobiotics. However, there is a lack of information about the mechanisms that take place at the cellular and molecular levels upon dual exposure to Cd and other toxins. The purpose of the present work was therefore to examine the biochemical interactions between Cd and a well-known genotoxic hepatocarcinogen, 2-acetylaminofluorene (AAF) in isolated rat hepatocytes. The cells were incubated for 10 hr with a sub-cytotoxic concentration (0.22 microM) of 109Cd. This was followed by a 10 hr exposure to 1 microM [3H]AAF. Cellular distribution of Cd and 3H was determined. Sephadex G-75 elution profiles of the cytosol showed that Cd was almost entirely associated with the intermediate molecular weight (IMW) fractions containing metallothionein (MT) ( > 80%), and with high molecular weight proteins. In parallel, the highest proportion of 3H was found in the low molecular weight components. Further analysis of IMW fractions by DEAE A-25 anion-exchange chromatography revealed that, in addition to Cd, there was some 3H which coeluted along with MT-I and MT-II isoforms, but preferentially with MT-I. Moreover, Cd pretreatment caused a 1.6-fold increase in MT level, as measured by the silver-saturation assay. Under these conditions, there was a 17% lower binding of 3H to the DNA. This reduced binding was neither accompanied by diminished AAF uptake nor by inhibition of cytochrome P-450 activity. Taken together, these results suggest that Cd exposure has a protective effect against the genotoxicity of AAF. MT, whose synthesis is induced, could play a role in the Cd-AAF interaction through scavenging of reactive metabolites.


Regulation of lipoprotein lipase activity in cardiac myocytes from control and diabetic rat hearts by plasma lipids.

The objective of this investigation was to test the hypothesis that the diabetes-induced reduction in lipoprotein lipase activity in cardiac myocytes may be due to hypertriglyceridemia. Administration of 4-aminopyrazolopyrimidine (50 mg/kg) to control rats for 24 h reduced plasma triacylglycerol levels and increased the heparin-induced release of lipoprotein lipase into the incubation medium of cardiac myocytes. The acute (3-5 days) induction of diabetes by streptozotocin (100 mg/kg) produced hypertriglyceridemia and reduced heparin-releasable lipoprotein lipase activity in cardiac myocytes. Treatment of diabetic rats with 4-aminopyrazolopyrimidine resulted in a fall in plasma triacylglycerol content and increased heparin-releasable lipoprotein lipase activity. Administration of Triton WR-1339 also resulted in hypertriglyceridemia, but the heparin-induced release of lipoprotein lipase from control cardiac myocytes was not reduced in the absence of lipolysis of triacylglycerol-rich lipoproteins. Treatment with Triton WR-1339 did, however, increase the heparin-induced release of lipoprotein lipase from diabetic cardiac myocytes. Preparation of cardiac myocytes with 0.9 mM oleic acid resulted in a decrease in both total cellular and heparin-releasable lipoprotein lipase activities. These results suggest that the diabetes-induced reduction in heart lipoprotein lipase activity may, at least in part, be due to an inhibitory effect of free fatty acids, derived either from lipoprotein degradation or from adipose tissue lipolysis, on lipoprotein lipase activity in (and (or) release from) cardiac myocytes.


Plasma atrial natriuretic factor and atrial wall stress in hypertensive and normotensive rabbits after pacing and volume expansion.

Atrial natriuretic factor (ANF) is present in high concentration in atria but in very low concentration in the ventricles. Under conditions of haemodynamic overload ventricular gene expression may become activated, but it is not clear if ventricular ANF can be released through a regulated or constitutive pathway. The purpose of this study was to determine whether basal and stimulated release of ANF are increased in perinephritic rabbits with mild hypertension. Six rabbits were rendered hypertensive by wrapping both kidneys in cellophane, and six sham-operated rabbits were used as controls. Eight weeks after renal wrapping, mean arterial pressure was approximately 20 mmHg higher in the experimental group. After anaesthesia, the renal-wrapped group had a higher vascular resistance. Right and left atrial wall stress was measured using sonomicrometry. Volume expansion by 30% of blood volume, using donor blood, caused a small increase in right and left atrial diastolic and systolic wall stress but did not significantly increase plasma ANF. Pacing the heart at 6 Hz caused increases in systolic but not diastolic wall stress and caused a significant increase in plasma ANF; the increase was larger after volume expansion. There were no significant differences between the responses of the experimental and control groups. It is concluded that mild hypertension, in the rabbit, does not lead to changes in atrial wall stress or either basal or stimulated release of ANF.


Effect of training and detraining on skeletal muscle glucose transporter (GLUT4) content in rats.

The aim of the present study was to examine the effects of treadmill exercise training and detraining on the skeletal muscle fiber type specific expression of the insulin-regulated glucose transporter protein (GLUT4) in rats. GLUT4 protein content was determined by Western and dot-blot analysis, using a polyclonal antibody raised against the carboxy-terminal peptide. Rats were sacrificed 24 h after the last training session. There were no significant changes in muscle GLUT4 after 1 day or 1 week of training. Six weeks of training increased GLUT4 protein content 1.4- to 1.7-fold (p < 0.05) over controls in the soleus and red vastus lateralis, whereas no significant change was evident in the white vastus lateralis muscle. GLUT4 protein content in both soleus and red vastus lateralis muscle returned to near control values after 7 days of detraining. Similar to GLUT4, citrate synthase activity showed no change after 1 day or 1 week of training, increased 1.8-fold over controls after 6 weeks of training, but returned to control values after 7 days detraining. These findings demonstrate that muscle GLUT4 protein is increased in rats with as little as 6 weeks of treadmill exercise training but that the adaptation is lost within 1 week of detraining. It is suggested that expression of the GLUT4 protein is coordinated with the well-documented adaptations in oxidative enzyme activity with endurance training and detraining.


Sensory irritation response in mice to sulfur dust.

The potential of sulfur dust to produce sensory irritation was evaluated in mice. Male Swiss--Webster mice were exposed by head-only inhalation to 106, 263, or 451 mg/m3 sulfur dust aerosol at room temperature. Breathing frequency and patterns were monitored before, during, and after exposure to evaluate the animal's sensory irritation response to the test atmosphere. Group average breathing rates were decreased 7 and 17% below pretest values in mice exposed to 106 and 263 mg/m3, respectively; however, breathing patterns appeared normal, indicating that there was no sensory irritation. Mice exposed to 451 mg/m3 showed an increase in breathing frequency of 7%, with 1/4 mice displaying very slight signs of pulmonary (deep lung) irritation. Some of the mice in the low- and high-dose groups exhibited signs of slight eye irritation immediately after exposure, but all mice were normal 1 day later. On the basis of these findings, exposure to sulfur dust up to 451 mg/m3 did not produce any sensory or upper airway irritation in mice.


Two-dimensional nuclear magnetic resonance studies of an intercalation complex between the novel semisynthetic anthracycline 3'-deamino-3'-(2-methoxy-4-morpholinyl)-doxorubicin and the hexanucleotide duplex d(CGTACG).

The complex of the hexanucleotide duplex d(CGTACG) and the antitumor drug 3'-(2-methoxy-4-morpholinyl)-doxorubicin was investigated by two-dimensional 1H nuclear magnetic resonance spectroscopy. After complete assignment of the non-exchanging DNA protons and nearly all drug protons, eight nuclear Overhauser enhancement interactions between drug and DNA were measured at short mixing times. A model was built which shows that the overall structure is very similar to the related daunomycin complex, with the new morpholinyl-substituent extending further into the minor groove of the DNA double helix. The structural information is used for the discussion of the possible formation of DNA-adducts by the new anticancer drug.


Arsenic induces and enhances rat hepatic metallothionein production in vivo.

Metallothionein genes (MT) are inducible by a variety of agents, including heavy metals. We report the induction of MT expression by arsenite (As3+) in rat liver in vivo. As3+ (but not arsenate [As5+]) injection increased MT protein and MT-1 and MT-2 mRNA accumulation in liver only, but not in kidney or pancreas. In addition, As3+ enhanced zinc-induced MT protein accumulation in liver without any increase in MT mRNA levels. These data indicate that arsenic may increase MT expression either directly (by inducing MT mRNA accumulation), or indirectly by altering post-transcriptional events. This constitutes an unusual mechanism of enhancement of MT gene expression and appears to be mediated by processes not specifically associated with binding of arsenite to MT in vivo.


Detection of tobacco smoke carcinogen-DNA adducts in cultured rat buccal mucosa cells following exposure to ethanol and total cigarette smoke condensate or chewing tobacco.

Formation of carcinogen-DNA adducts in rat oral epithelial cells after treatment with cigarette smoke condensate (CSC) or chewing tobacco in the presence of ethanol was investigated using the 32P-postlabeling procedure. Concomitant treatment of the cells with ethanol increased the relative adduct level over that found in cells treated with tobacco smoke condensate only. Treatment with chewing tobacco resulted in slightly higher adduct levels than in controls. Treatment of the cells with ethanol did not significantly increase the uptake of a polycyclic aromatic hydrocarbon, benzo[j]fluoranthene, however, high tar CSC alone or in combination with ethanol significantly increased the uptake of radiolabeled benzo[j]fluoranthene, suggesting that increased uptake of the carcinogens may be one of the synergistic mechanisms of alcohol in oral carcinogenesis.


Study on the regioselectivity and mechanism of the aromatic hydroxylation of monofluoroanilines.

The in vitro and in vivo metabolism of monofluoroanilines was investigated. Special attention was focused on the regioselectivity of the aromatic hydroxylation by cytochromes P-450 and the mechanism by which this reaction might proceed. The results clearly demonstrate that the in vitro and in vivo regioselectivity of the aromatic hydroxylation by cytochromes P-450 is dependent on the fluoro-substituent pattern of the aromatic aniline-ring. Results from experiments with liver microsomes from differently pretreated rats demonstrate that the observed regioselectivity for the aromatic hydroxylation is not predominantly determined by the active site of the cytochromes P-450. To investigate the underlying reason for the observed regioselectivity, semi-empirical molecular orbital calculations were performed. Outcomes of these calculations show that neither the frontier orbital densities of the LUMO/LUMO + 1 (lowest unoccupied molecular orbital) of the monofluoroanilines nor the spin-densities in their NH. radicals can explain the observed regioselectivities. The frontier orbital densities of the HOMO/HOMO - 1 (highest occupied molecular orbital) of the monofluoroanilines however, qualitatively correlate with the regioselectivity of the aromatic hydroxylation. Based on these results it is concluded that the cytochrome P-450 dependent aromatic hydroxylation of monofluoroanilines does not proceed by hydrogen or electron abstraction from the aniline substrate to give an aniline-NH. radical. The results rather suggest that cytochrome P-450 catalyzed aromatic hydroxylation of monofluoroanilines proceeds by an electrophilic attack of the (FeO)3+ species of cytochrome P-450 on a specific carbon atom of the aromatic aniline-ring.


HPLC separation of 32P-postlabelled DNA adducts formed from dibenz[a,h]anthracene in skin.

Mouse skin and human skin have been treated in vivo or in short-term organ culture with dibenz[a,h]anthracene (DB[a,h]A), the related 3,4- or 5,6-diols or the anti- or syn-3,4-diol 1,2-oxides. DNA hydrolysates have been 32P-postlabelled and the adducts present examined by HPLC using a phenyl-modified reverse phase column and, for comparison, by PEI-cellulose TLC and autoradiography. The adducts formed when the diol-epoxides were reacted with salmon sperm DNA were also examined. The results show that in mouse skin treated in vivo, the major adducts formed from DB[a,h]A and the 3,4-diol were the same and that two of them were more polar than those formed in skin or in DNA that had been treated with the related anti- or syn-diol epoxides. Human skin treated with DB[a,h]A in culture yielded an adduct profile that was qualitatively similar to the profiles obtained with mouse skin.


A comparative binding of platinum anti-tumour compounds to plasma proteins in the rat (in vivo) and mouse (in vitro).

Plasma protein binding of 195mPt-labelled cisplatin, carboplatin and iproplatin has been studied in vivo in rat and in vitro in mouse, using both electrophoresis and trichloroacetic acid precipitation. After intravenous injection plasma clearance rates were biphasic for all 3 compounds, (t1/2 alpha, 13-17 min) but cisplatin was retained thereafter longer than the others. By 5 min, gel electrophoresis showed protein labelling with all 3 drugs but none involved low mol.wt. proteins (< 16 kDa). At 2 h a notable proportion of the protein bound platinum was associated with the latter components. There was a general resemblance between the distribution patterns of cisplatin and carboplatin whereas iproplatin showed a persistent retention of the label with time to higher mol. wt. proteins. From in vitro incubation with mouse plasma, rates of interaction respectively were cisplatin t1/2 alpha, 35 min, beta 8 h, carboplatin t1/2, 44 h and iproplatin t1/2, 104 h. By electrophoresis the protein bound fraction pattern (1 h) was again similar for cisplatin and carboplatin with virtually no binding to low mol. wt. proteins. After 24 h these were now involved to a high degree (40%). Iproplatin showed relatively marked binding to proteins of higher mol. wt. but no transfer with time to the low mol. wt. protein zone. A possible explanation is the need for in vivo metabolism for this compound as manifest in the rat. It is suggested that the significance of interaction with low mol. wt. proteins merits further investigation in relation to the antitumour and toxicological actions of these drugs.


pH effects on the N-demethylation and formation of the cytochrome P-450 iron II nitrosoalkane complex for erythromycin derivatives.

The effects of pH on access to the cytochrome P-450 active site, N-demethylation and formation of the cytochrome P-450 Fe(II)-RNO metabolite complex for a series of erythromycin derivatives were examined. Studies were performed with dexamethasone-treated rat liver microsomes containing large amounts of cytochrome P-450 3A isozymes. In addition to factors such as hydrophobicity or hindrance around the dimethyl-amino function, the ionisation state of the N(CH3)2 group played an important role in the recognition and metabolism of the substrate by cytochrome P-450. Esterification of the desosamine in the beta position of the N(CH3)2 group leads to lower pKa values for the R--N+ H(CH3)2 <--> [R--N (CH3)2] + H+ equilibrium. At physiological pH, the amine group is mainly in the unprotonated form. Consequently, easier access to the protein active site and significant formation of cytochrome P-450 Fe(II)-RNO metabolite complex are observed for these derivatives. These results led us to interpret the formation of cytochrome P-450 Fe(II)-RNO metabolite complex as a series of multiple steps equilibria depending on the ionisation state of the N(CH3)2 group, the partition coefficient of the substrate between the microsomal layer and the aqueous media and a series of metabolic reactions leading partially to the final inhibitory nitrosoalkane-cytochrome P-450 Fe(II) complex.