Postmortem neurochemistry in schizophrenia

The renaissance in postmortem studies in schizophrenia is in full bloom. Although there is no shortage of findings, there have been significant problems with replications and interpretations. Regardless, the postmortem approach remains a valid and promising one. Thus far, it has allowed for the testing of a number of hypotheses involving catecholamines, indoleamines, and neuropeptides in schizophrenia. It is hoped that new approaches, such as autoradiography and automated cell counting, will add new dimensions to postmortem studies of schizophrenia. If these studies can be coupled with premortem exams of patients, perhaps new inroads can be made in the understanding and treatment of the schizophrenic syndrome.     

Clinical and instrumental assessment of neuroleptic-induced parkinsonism in patients with tardive dyskinesia.

We evaluated 21 right-handed psychiatric patients with tardive dyskinesia (TD) for the presence and laterality of neuroleptic-induced tremor and rigidity. The goals of the study were to assess the frequency and coexistence of TD and neuroleptic-induced parkinsonism (NIP) using instrumental and clinical measurements and to evaluate the hypothesis that when TD and NIP coexisted in the same patient, they were more likely to appear in opposite limbs. Results indicated that a high percentage of TD patients had coexisting rigidity and tremor on the basis of both clinical ratings and instrumental procedures; however, only instrumental procedures were useful in identifying tremor and rigidity asymmetries. We found that TD and tremor or rigidity did not lateralize to opposite limbs, thus weakening the hypothesis that TD and NIP stemmed from reciprocal pathophysiological mechanisms.     

Evidence for covalent attachment of fatty acids to Sindbis virus glycoproteins.

Selective binding of lipid to glycoprotein was detected when [3H]palmitate-labeled Sindbis virus particles or viral-infected cells were disrupted by heating with sodium dodecyl sulfate, and glycoproteins were isolated by electrophoresis in sodium dodecyl sulfate/10% polyacrylamide gels. The smaller glycoprotein (E2) retained 2 to 3 times more labeled lipid than did the larger EI glycoprotein, and the cell-associated glycoprotein precursor (PE2) bound even less lipid. No lipid was associated with the nonglycosylated glycoproteins that accumulated in infected cells treated with tunicamycin. The labeled lipid remained bound to the glycoproteins after exhaustive extraction with chloroform/methanol of virus particles, infected-cell extracts, or isolated glycoproteins, but it could be extracted by chloroform/methanol after treating glycoproteins with mild alkali. Analysis by gas/liquid chromatography showed that 60% of the label was in palmitate and the balance of label was distributed between oleate and stearate. There were approximately 2 mol of fatty acid bound per mol of E1 glycoprotein. Proteolysis of the fatty acid-labeled glycoprotein with pepsin, thermolysin, and Pronase degraded the polypeptide to fragments that retained the fatty acids in an alkali-labile state. These data suggest that a covalent attachment of fatty acid may occur during maturation of the viral glycoproteins.     

Induction of Gastrointestinal Tumors in Mice Fed the Fungicide Folpet: Possible Mechanisms

Dietary administration of the fungicide folpet, N-(trichloromethylthio)phthalimide, to B6C3F¹ mice at dose levels of 1,000, 5,000 and 10,000 ppm induced a dose-related appearance of duodenal atypical hyperplasia, adenomas and adenocarcinomas. The appearance in some of these animals of gastric papillomas and gastric squamous cell carcinomas was correlated in many instances to the presence of duodenal obstructions. It is suggested that the gastric lesions appeared subsequent to, and as an indirect result of, these partial lumenal duodenal obstructions. We suggest that the presence of duodenal obstructions is consistent with the notion that reflux of folpet, bile acids and pancreatic enzymes into the stomach may have acted to irritate and consequently stimulate local neoplastic proliferation. In addition, the duodenal obstructions may have resulted in delayed emptying time of the stomach contents with consequential stagnation. This would cause high concentrations of folpet to act locally on the gastric mucosa.     

Association of psychosis and movement disorders in the elderly

There are a number of different relationships among aging, psychosis and movement disorders, most of which have been proposed to involve the neurotransmitter dopamine. Dopamine content and dopamine receptors have been shown to decrease with age, which may relate to the time of onset of different motor and psychotic disorders, as well as to the appearance of these disorders. For example, some so-called senile movement disorders, such as senile tremor and senile chorea, may relate to alterations in dopaminergic transmission with age, as might the general findings of increased slowing of movements and mildly increased rigidity with age, although it is not clear how common some of these changes are in the medically healthy elderly. Decrease in dopamine with age may also be associated with the findings that choreiform and psychotic disorders (which have been proposed to be related to excess dopaminergic activity) tend to predominate at younger ages, whereas parkinsonism is more common at later ages. Certain findings support this notion, such as the appearance of both dyskinesia and psychosis in patients treated with L-dopa, the finding that psychosis may be less common in patients with later-onset Huntington's disease, and the fact that neuroleptic-induced parkinsonism is often more severe in the elderly. However, the situation is more complicated than this, because there are a number of phenomena that do not fit the pattern, including the observation of an increased incidence of tardive dyskinesia in the elderly. Age-related changes in other transmitters are undoubtedly important in both movements disorders and psychosis, and even dopamine has been proposed to have both trophic and toxic properties over the aging process. In general, care is warranted in the use of any psychotropic medications in the elderly, because there can be widespread and often unpredictable effects of these drugs on both motor and mental function.     

The relationship between leftward turning bias and visuospatial ability in humans.

A significant relationship was found between a bias to make complete counter-clockwise (leftward) turns and performance levels on tests of visuospatial function. Subjects who turned preferentially to the left over a four-day period performed above average on visuospatial tests with those having the greatest turning bias performing the best. Subjects who tended to turn to the right performed below average on tests of visuospatial function. There was no relationship between rotational bias and verbosequential skills, but there was a significant relationship between turning bias and a cognitive profile defined as the difference between visuospatial ability and verbosequential ability. The cognitive profile effectively partialed out overall ability suggesting that the turning bias is related to the bias for better visuospatial processing rather than the level of visuospatial performance per se. Asymmetric turning has been shown to be related to asymmetries of dopamine activity in rats. Therefore, the present results are discussed in relation to the possibility that the dopamine neurotransmitter system may underlie both rotational behavior and visuospatial cognitive function in humans.     

A village-sclae trial with dichlorvos as a residual fumigant insecticide in southern Nigeria

Hut and village-scale trials with solid and liquid-type dichlorvos dispensers were carried out in 1961 in the vicinity of Lagos, Nigeria, by the WHO Insecticide Testing Unit. Bioassay results indicated that with a single application satisfactory mortalities of caged mosquitos could be obtained for a period of 12-13 weeks in mud-walled huts, whether with galvanized corrugated-iron roofs or with thatched roofs. Chemical analysis of air samples showed that satisfactory concentrations of dichlorvos vapour were maintained throughout the huts for about 12 weeks, after which time sublethal concentrations were observed first near the floors of the dwellings. No depression in blood or plasma cholinesterase was noted in the exposed inhabitants     

Infertility: Human decidua-associated protein hDP200 in menstrual fluid: comparison between fertile women and women after failed in-vitro fertilization/embryo transfer treatment

The concentration of human decidua-associated protein (hDP)200 was measured in 238 menstrual fluid samples obtained fromnormal fertile women and in 26 menstrual fluid samples obtainedfrom infertile women who failed to conceive and menstruatedfollowing in-vitro fertilization (IVF)/embryo transfer treatment.A significant association was observed between the concentrationof hDP200 and the age of the women. A maximal concentrationof hDP200 was observed in women aged 28–30 years, withsignificantly lower concentrations in those aged 18–20and 39–41 years. The presence of an intra-uterine devicehad no effect on menstrual fluid hDP200 concentrations. A significantlylower mean concentration of hDP200 (82 U/ml) was measured inmenstrual fluid samples obtained from failed IVF/embryo transferpatients as compared with that in menstrual fluid samples fromnormal fertile women (191 U/ml). These findings support theconcept that adequate endometrial function, as evaluated bymenstrual fluid concentration of hDP200, is important for thesuccess of the fertility process.