Porphyria cutanea tarda associated with HIV infection.
Explore the source record for details and available documents.
Adult↗
Biomedical subjects
I Martin
Publications and source records attributed to I Martin.
Electrotherapy in mice: dopaminergic and noradrenergic effects in the Tail Suspension Test.
The Tail Suspension Test (TST) is a psychotropic screening test which is used principally to detect antidepressant activity. Electrotherapy (ECT) is used to treat depressions which are resistant to the usual antidepressant drugs and has proved to have a profile in the TST approaching that of antidepressants after treating mice at the rate of 2 shocks per day for 5 days. The results of a single treatment were not statistically different from those of the control group, whereas single daily treatment for 5 days showed a reduction in immobility which did not differ significantly from the control group. The reduction in immobility, induced by 5 days of ECT treatment twice daily, was antagonized by sulpiride and prazosin but not by yohimbine, methysergide, metergoline and DL propranolol. The results suggest that electrotherapy leads to an increase in noradrenergic and dopaminergic activities expressed by a reduction in immobility in the TST.
Animals↗
Adaptative decrease in expression of the mRNA for uncoupling protein and subunit II of cytochrome c oxidase in rat brown adipose tissue during pregnancy and lactation.
Uncoupling-protein (UCP) mRNA expression is decreased to 15% of virgin control levels between days 10 and 15 of pregnancy, and remains at these low values during late pregnancy and lactation. Abrupt weaning of mid-lactating rats causes a slight but significant increase in UCP mRNA. Expression of mRNA for subunit II of cytochrome c oxidase (COII) decreased to half that of virgin control in late pregnancy and during lactation. Whereas COII mRNA expression is in step with the known modifications of brown-fat mitochondria content during the breeding cycle of the rat, UCP mRNA expression appears to be diminished much earlier than the mitochondrial proton-conductance-pathway activity. On the other hand, the reactivity of brown fat to increase expression of UCP and COII mRNAs in response to acute cold or noradrenaline treatment is not impaired during lactation.
Adipose Tissue, Brown↗
Separation and molecular weight determination of prostaglandin B1 oligomers by size-exclusion chromatography.
An efficient size-exclusion chromatographic method for the simultaneous separation and molecular weight (MW) determination of prostaglandin (PG) oligomers on Sephadex G-50 with borate buffer is described. The prostaglandins 15-keto-PGB1 and 16,16-dimethyl-15-keto-PGB1 were used for the synthesis of oligomers. MW determinations in the monomer to octamer range is based on the linear correlation between the partition coefficient and log (MW) of the oligomers. The essential role of the borate anion between the gel matrix and the oligomers is demonstrated.
Chemical Phenomena↗
Secondary structure and orientation of a chemically synthesized mitochondrial signal sequence in phospholipid bilayers.
A pre-sequence of 25 amino acids is required for import of yeast cytochrome oxidase subunit IV into mitochondria. Structure and orientation of the 25 amino acids synthesized peptide (p25) in a lipid bilayer were investigated by infrared attenuated total reflection spectroscopy. This method allowed to overcome the difficulties related to the optical turbidity due to the light scattering on membrane fragments which prevents the use of circular dichroism. We demonstrate here that incubation of the peptide with DOPC (dioleoylphosphatidylcholine) and DOPC-CL (dioleoylphosphatidylcholine - cardiolipin) liposomes is accompanied by an increase in alpha-helical content as compared to beta structure. Polarisation measurements indicate that the amphipathic helical segment is inserted parallel to the lipid acyl chains in cardiolipin containing liposomes.
Cardiolipins↗
Propositional knowledge and mere responding.
This commentary examines views recently offered by Furedy and Riley (1987) on the nature of classical conditioning. Their analysis identifies propositional learning as a component of conditioning separate from response acquisition. They reserve to this component the label cognitive on the epistemological grounds of falsifiability. We suggest that this analysis does not do justice to the concept of cognition in human conditioning. In particular it limits the scope of propositional knowledge to a formal role in the conditioning paradigm and ignores the recent development of propositional models in cognitive science. In seeking to integrate their propositional account with animal conditioning theory they usefully map their two processes on to the conditioned response/instrumental response distinction proposed by Gormezano and Kehoe (1975). However, their propositional contingency interpretation of the Rescorla and Wagner (1972) theory ignores the essentially associative mechanism used in the model to account for interevent relations.
Animals↗
Time-dependent effects of alcohol on the hypothalamic-hypophyseal-testicular function in the rat.
Adult male rats were followed throughout ethanol administration, in order to examine the time-dependent effects of ethanol on the hypothalamic-pituitary-gonadal axis. The results indicate that there is an increase in plasma prolactin levels together with a reduction in basal plasma luteinizing hormone (LH) levels, which are evident from the beginning of the intoxication period. An exaggerated response of LH to luteinizing hormone-releasing hormone was also evident from 2nd week on, in ethanol-treated rats. Basal and human chorionic gonadotropin-stimulated plasma testosterone levels were decreased in alcohol-treated as compared to control rats, at all time points studied. In addition, plasma estradiol levels were increased in ethanol-fed rats. These data suggest a direct suppressive effect of ethanol on LH release in the beginning of the intoxication period. Subsequent elevations of plasma estradiol and prolactin levels may have contributed to the maintenance of hypogonadism at the end of the intoxication period.
Animals↗
Induction and metabolite regulation of levanase synthesis in Bacillus subtilis.
Levanase expression in Bacillus subtilis was studied by using transcriptional and translational fusions. It was shown that the degradative products of levan or inulin and low concentrations of fructose were able to induce levanase expression. In the wild-type strain and in a constitutive overproducing sacL mutant, levanase synthesis was repressed by glucose or fructose. This catabolite repression was partially abolished in the derepressed alpha-amylase gra-26 mutant. The levanase gene (sacC) appears to be the distal gene of an operon transcribed from a fructose-inducible promoter. Deletion mapping experiments and primer extension analysis revealed a transcriptional start point located 2.7 kilobases upstream from the sacC gene. Two constitutive sacL mutations were shown to be closely linked by transformation to the sacC gene. The sacL6 and sacL8 mutations were mapped in the promoter-proximal region of the operon.
Amino Acid Sequence↗
Intraoperative radiotherapy in the multidisciplinary treatment of pediatric tumors. A preliminary report on initial results.
From September 1984 to July 1987, 33 children received intraoperative radiotherapy as part of a multidisciplinary tumor treatment. Their age ranged from 2 to 17 years. Tumors types: Ewing's sarcoma (n = 11), osteosarcoma (n = 8), soft tissue sarcomas (n = 5), Wilms' tumor (n = 3), neuroblastoma (n = 3), malignant pheochromocytoma (n = 1), Hodgkin's disease (n = 1), and optic nerve glioma (n = 1). In 25 patients the disease was localized while 8 had distant metastases. Intraoperative radiotherapy was used in 26 previously untreated patients as part of a radical treatment program and in 7 cases as an effort to rescue local failures (5 in previously irradiated areas). The intraoperative radiation field included the surgically exposed tumor or tumor bed, and the single doses ranged from 10 to 20 Gy, with 6-20 MeV electrons. Patients with osteosarcoma and recurrent tumor in a previously irradiated area did not receive postoperative external beam radiotherapy. With a median follow-up time of 10 months (1 to 31 + months) 24 out of 33 patients are alive without local recurrence and 9 have died from tumor (5 with local disease progression). Intraoperative radiotherapy seems to be a feasible treatment which might promote local control in pediatric tumors.
Adolescent↗
Evidence for a differential physiological modulation of brown fat iodothyronine 5'-deiodinase activity in the perinatal period.
Brown adipose tissue iodothyronine 5'-deiodinase increases progressively in fetuses from the day 17 of pregnancy on, it reaches peak values on the 20th day of gestation and declines in the last days of fetal life as well as during the first day of life. Birth of premature fetuses causes a sudden drop in the enzyme activity. Postmaturity is associated to a decrease in brown fat 5'-deiodinase similar to that found after birth in fetuses born at term. In the first hours of life brown fat iodothyronine 5'-deiodinase is essentially insensitive to the cold-stimulus. Present data indicates that, differently from adult rats, brown fat iodothyronine 5'-deiodinase activity during the perinatal period is dissociated from the thermogenic activity of the tissue. It is suggested that factors different from the action of the sympathetic nervous system may play a main role in brown fat iodothyronine 5'-deiodinase activity modulation in the fetal and neonatal life.
Adipose Tissue, Brown↗
Effects of RO 15-1788 on a running response rewarded on continuous or partial reinforcement schedules.
Two experiments were run in which rats were rewarded with food for running in a straight alley at one trial a day, followed by extinction of the running response. During acquisition of the response, reward was delivered either on a continuous reinforcement (CRF) or on a quasirandom 50% partial reinforcement (PRF) schedule. The groups given PRF were more resistant to extinction than those given CRF, the well-known partial reinforcement extinction effect. In Experiment 1 different groups of rats were injected during acquisition only with 1, 5 or 10 mg/kg of the benzodiazepine antagonist, RO 15-1788, or with placebo. In Experiment 2, 5 mg/kg RO 15-1788 or placebo were administered in a full cross-over design during acquisition, extinction or both. At the end of Experiment 2 only [3H]-flunitrazepam binding was measured in either the presence or absence of added gamma-aminobutyrate (GABA) in homogenates of hippocampi dissected from the animals that had received behavioural training. The drug affected running speeds during both acquisition and extinction in different ways depending upon the schedule of reinforcement (CRF or PRF) and also gave rise to enhanced GABA stimulation of [3H]-flunitrazepam binding. The results are discussed in relation to the hypothesis that the neurochemical pathways by which reinforcement schedules modify behaviour include a step influenced by benzodiazepine receptors.
Animals↗
Possible role of prolactin in the induction of hypogonadism by chronic alcohol treatment in the male rat.
Treatment of adult male rats with ethanol for a period of six weeks resulted in a numerical but not significant increase in plasma prolactin levels together with a reduction in plasma luteinizing hormone (LH) levels. Although basal plasma testosterone (T) levels were not affected in ethanol-treated animals, testicular weight was reduced and seminiferous tubules exhibited signs of atrophy. The responses of LH to luteinizing hormone releasing hormone (LHRH) and T to hCG were significantly impaired in ethanol-treated rats (p less than 0.01). Treatment with bromocriptine (1 mg/kg body weight/day), resulted in the expected decrease in plasma levels of prolactin and an increase in basal plasma LH levels to the levels found in control groups. Basal plasma T levels were not affected by bromocriptine. However, both plasma LH responses to LHRH and plasma T responses to hCG were significantly improved by bromocriptine treatment in alcoholic rats and became similar to the responses measured in control animals. The results suggest that bromocriptine-induced suppression of prolactin release has a beneficial effect on ethanol-induced hypogonadism.
Alcoholism↗
Classical conditioning in a cognitive era.
Classical conditioning as a body of laboratory techniques and the phenomena which they have generated has a long history in behavioural science. Today, the emphasis on cognitive processes which has overtaken behavioural science threatens to displace the older technology. This paper examines those aspects of classical conditioning which might be expected to contribute a useful supplement to the cognitive description of human functioning. It is suggested that the emphasis on individual differences and on the modulation of affect and preference constitutes the core of this contribution.
Anxiety Disorders↗
Risk factors in the population of the GDR-MONICA Study (1983/84).
The GDR-MONICA project comprises 25 administratively defined areas with a population of nearly two million people aged 25-64. Data from the first random sample survey are reported here. The survey gathered information regarding risk factors, dietary behaviour, physical activity and psychosocial factors from 11,281 persons aged 25-64. The average risk factor levels were high in the population: The mean casual blood pressure was 140/88 mmHg and 138/86 mmHg for men and women respectively. In both sexes the mean total cholesterol level exceeded 6.1 mmol/L, and the mean body mass index (BMI) was just over 26.0. The study population consumed, on average, excessive amounts of energy, fat, alcohol, and sodium, and too few carbohydrates. Preliminary conclusions regarding unfavourable trends in risk factor levels have been drawn by comparing the present data with other recent reliable epidemiological studies.
Adult↗
A comparison of the effects of oxodipine and nifedipine on rat vas deferens.
The effects of oxodipine, a new dihydropyridine, were studied and compared with those of nifedipine in the complete vasa deferentia and in the prostatic and epididymal halves of the rat vas deferens. Oxodipine and nifedipine, 10(-9) -10(-6)M, produced a dose-dependent inhibition of the contractile responses induced by single pulse stimulation, noradrenaline (3 x 10(-5)M) and high-K (50 mM). The inhibitory effects of oxodipine were significantly reduced in high Ca media. From these experiments it is concluded that oxodipine, like nifedipine, produced a similar and potent inhibitory effect of the contractile responses induced in the rat vas deferens.
Animals↗
Dermatitis artefacta complicated by a cerebral abscess.
Explore the source record for details and available documents.
Brain Abscess↗
Characterization of the levanase gene of Bacillus subtilis which shows homology to yeast invertase.
The structural gene for the enzyme levanase of Bacillus subtilis (SacC) was cloned in Escherichia coli. The cloned gene was mapped by PBS1 transduction near the sacL locus on the B. subtilis chromosome, between leuA and aroD. Expression of the enzyme was demonstrated both in B. subtilis and in E. coli. The presence of sacC allowed E. coli to grow on sucrose as the sole carbon source. The complete nucleotide sequence of sacC was determined. It includes an open reading frame of 2,031 bp, coding for a protein with calculated molecular weight of 75,866 Da, including a putative signal peptide similar to precursors of secreted proteins found in Bacilli. The apparent molecular weight of purified levanase is 73 kDa. The sacC gene product was characterized in an in vitro system and in a minicell-producing strain of E. coli, confirming the existence of a precursor form of levanase of about 75 kDa. Comparison of the predicted aminoacid sequence of levanase with those of the two other known beta-D-fructofuranosidases of B. subtilis indicated a homology with sucrase, but not with levansucrase. A stronger homology was detected with the N-terminal region of yeast invertase, suggesting the existence of a common ancestor.
Amino Acid Sequence↗