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Biomedical subjects

M Stevens

Publications and source records attributed to M Stevens.

At least 199 records · Page 11Linked to original sources
PubMed1982

Skin conductance habituation during acute episodes of schizophrenia: qualitative differences from anxious and depressed patients.

Skin conductance habituation was measured in schizophrenic patients (N = 41) during an acute episode and compared with neurotic patients (N = 86) who were either predominantly anxious or predominantly depressed. All patients were tested before the onset of drug treatment. Between the 14th and 15th tone of the 17 tone simple habituation series a loud 'dishabituating' tone was inserted. In terms of traditional measures based on response frequency, non-habituation was most frequent in the anxious patients and least frequent in the depressed patients, with schizophrenic patients being intermediate. However, in terms of response amplitude the schizophrenic patients showed significantly faster habituation than either neurotic group. This paradox seems to be a consequence of the frequency of spontaneous fluctuations which was highly related to habituation status in the schizophrenic group, but not in the neurotic groups. When habituation was defined in terms of response amplitudes falling below spontaneous fluctuation amplitudes (rather than zero) the schizophrenic group showed the lowest frequency of non-habituation. None of the groups showed any evidence of dishabituation after the loud tone, but the schizophrenics showed a significantly smaller response to the loud tone itself. Following Groves & Thompson (1970), this is interpreted as showing that the loud tone induced a greater response because of its perceived difference from the other tones rather than a sensitization effect because of its loudness. In these terms the schizophrenic patients showed greater response generalization than the neurotic patients.

Acute Disease↗
PubMed1981

Numerical taxonomy of Pseudomonas based on published records of substrate utilization.

Data published by R. Y. Stanier, N. J. Palleroni, M. Doudoroff and their colleagues on Pseudomonas have been analysed by numerical taxonomy. Records on 401 strains were used, representing 155 characters, mostly utilization of substrates as carbon-energy sources. Twenty-nine phenons were recognized, which included 394 strains: the remaining 7 remained unclustered. The results were in very good accord with the conclusions of these authors. Almost all phenons were well separated with very little overlap. Many of them corresponded to distinct species, and others corresponded to recognized biotypes. Some small groups may represent unnamed new species. Analyses by Gower's Coefficient showed five major groupings: A) the fluorescent pseudomonads; B) biochemically active species (Pseudomonas cepacia, P. pseudomallei and allies); C) moderately active free-living species (P. acidovorans, P. alcaligenes and allies); D) P. solanacearum and allies; and #) P. mallei P. diminuta does not appear to be clearly distinct from P. vesicularis, nor does P alcaligenes appear clearly distinct from P. pseudoalcaligenes. There may, however, be some difference between P. multivorans and P. cepacia. Analyses using the Pattern Coefficient differed mainly in the relationships shown by a few of the metabolically active species. Of the two coefficients, the Pattern Coefficient gave results that were in somewhat better agreement with evidence from nucleic acids, but it showed an unexpectedly close relationship between P. solanacearum and P. cepacia.

Fluorescence↗
PubMed1981

The relationships between clinical response, psychophysiological variables and plasma levels of amitriptyline and diazepam in neurotic outpatients.

In a 4 week study of the response of neurotic outpatients to treatment with amitriptyline, diazepam, amitriptyline and diazepam, or placebo clinical and psychophysiological variables and plasma levels of the drug were assessed. Clinical improvements were substantial in all treatment groups but clear relationships between clinical change, psychophysiological change and plasma levels of the drugs were not established. There was no relationship between plasma levels of the drugs and cigarette smoking. It is concluded that neither plasma levels of amitriptyline and diazepam nor change in skin conductance responsivity offer a useful guide to clinical response to drug treatment.

Adult↗
PubMed1980

Study of red blood cell and serum enzymes in five Pyrenean communities and in a Basque population sample.

Until recently, no data on genetic polymorphisms in the populations living on the northern side of the Pyrenees have been available, except for the Basques. Several investigations were done lately on rural communities in various geographic zones in the Pyrenees from the eastern to the western part. In this paper, the results for the following enzyme polymorphisms are reported: acid phosphatases, AK, ADA, PGM1 and PGM2, 6PGD, NADH diaphorase, SOD, MDH, TGP, G6PD, C5 esterase (E2 locus), serum cholinesterase (E1 locus). Significant variation in gene frequencies was observed over the distinct geographic zones for the main polymorphic system. Furthermore, some rare alleles were found: a new G6PD variant (Luz-Saint-Sauveur), the presence of ADA3 and ADA5 alleles in two groups of the Central Pyrenees, a Dia2 gene among Basques and in the Pays de Sault, a high rate of Ea1 allele in the Basque group. The values obtained for the degree of heterozygosity are in agreement with the relative isolation of the different groups studied and confirm the importance of sociocultural factors in the evolution of the genetic background of rural communities in Europe.

Acid Phosphatase↗
PubMed1980

Identification of testicular cell plasma membrane receptors for calcitonin.

Recent studies have suggested a role for CT in the serum and tissue zinc homeostatic mechanism. The effects of CT on zinc transport appeared to be most pronounced in testis and thymus. If these effects are physiologically important, a cell membrane CT receptor, similar to those described for other peptide hormones, ought to be demonstrable. Rat testicular and hepatic cell membranes were isolated on a linear 15% to 50% sucrose density gradient. Specific hormone binding was assessed by Scatchard analysis of the binding of a constant amount of radiolabeled hormone in the presence of known variable amounts of unlabeled hormone. Nonspecific binding was assessed by measurement of radiolabeled hormone binding in the presence of 10(3) molar excess of unlabeled hormone. Hepatic cell membrane demonstrated no specific binding of either 125I-synthetic human CT or 125I-synthetic 1-34 bovine PTH. Testicular cell membranes demonstrated no specific binding for PTH. CT, however, was specifically bound with a mean KD of 3.2 +/- 0.8 X 10(-8) (S.E.M.) mol/L (M). Specificity studies demonstrated no inhibition of CT binding of 10(2) molar excess of FSH, LH, 1-34 PTH, or insulin. These data suggest the presence of a specific plasma membrane receptor for CT in rat testes. The presence of a membrane receptor in this tissue is consistent with previous observations that CT can alter the zinc content of rat testis in vivo.

Animals↗
PubMed1979

Skin conductance responsivity during acute episodes of schizophrenia as a predictor of symptomatic improvement.

Skin conductance responses to a series of tones were measured in 41 patients during an acute episode of schizophrenia before they received treatment and after 4 weeks of treatment with either alpha-flupenthixol, beta-flupenthixol or placebo. Patients who did not habituate to the tones prior to treatment tended to show no symptomatic improvement during the course of treatment. Patients who habituated and also showed an acute onset of their current symptoms ('Feighner negative' patients) showed a marked improvement even without active medication. Skin conductance responsivity did not change with improvement in symptoms alone, but decreased in patients on active medication (alpha-flupenthixol). Non-habituation of skin conductance and insidious onset (i.e. fulfilment of the Feighner criteria) were found to be independent predictors of poor outcome. Taken together, these criteria may define a group of patients with particularly poor prognosis.

Acute Disease↗
PubMed1979

The outcome of severe acute schizophrenic illnesses after one year.

Forty-five patients with acute schizophrenic illnesses (defined by PSE criteria) were assessed in clinical, cognitive and social terms before being entered in a four week study of the isomers of flupenthixol and placebo. At the end of one year they were re-assessed in the same terms. The clinical and psychological features of the acute illness and the drug treatment given did not predict outcome. Poor outcome in social terms was significantly related to severe social isolation in the initial assessment and to the presence of nuclear symptoms and negative schizophrenic features at follow-up.

Acute Disease↗
PubMed1978

Age disorientation in schizophrenia: a constant prevalence of 25 per cent in a chronic mental hospital population?

The prevalence of age disorientation was estimated in the population of patients with a diagnosis of schizophrenia in a large mental hospital. Of these 357 patients 25 per cent demonstrated age disorientation, defined as a five-year discrepancy between true and subjective age, and 11 per cent of the population believed themselves to be within five years of the age they were at admission, although they were a mean 28.9 years older. Age-disorientated patients differed from the age-orientated in being significantly older. However, when age-matched, they were younger at first admission and had a longer duration of stay than patients with a diagnosis of schizophrenia without age-disorientation. Age-disorientation may thus be a feature of a type of schizophrenic illness of early onset and poor prognosis.

Adult↗
PubMed1978

Age disorientation in chronic schizophrenia: the nature of the cognitive deficit.

In an interview survey of temporal orientation in chronic schizophrenia, patients with age disorientation (n = 77) were much less likely than patients without age disorientation (n = 222) to be able to give correct answers to simple questions about dates and the passage of time (e.g. their date of birth, the present year and the duration of their hospital stay). The age disorientated systematically under-estimate the present year and their duration of hospital stay; in individual patients the errors they make are consistent with their concept of their own age. "Time stands still" for these patients. However, there are patients in whom an incorrect appreciation of their own age co-exists with correct awareness of the present year. Between these patients and those for whom subjective time stands still, there appears to be a continuum of increasing temporal disorientation. This dimension may be a clinical correlate of intellectual impairment.

Age Factors↗
PubMed1977

A study of the increased serum level of IgG1 in 'lethargic' mice combined with a depressed thymus-dependent lymphoid system.

In a series of recent studies on 'lethargic' mice, a neurological mutation of the mouse, significant abnormalities were discovered in the thymus and its dependent regions in the lymph nodes and spleen. The present study was made as an approach toward finding the possible causes for these abnormalities. Serum IgG1 levels were stldied in 'lethargic' mutants at the age when severe deficiency of the thymus-dependent lymphoid system is known to occur in the animal. Using the radial immunodiffusion method, it was found that serum IgG1 levels are always significantly higher in 'lethargic' mice than in their normal littermates. Possible causes of the higher IgG1 in the serum of 'lethargic' mice are discussed. The authors note the similarities of other mouse mutations to that of the 'lethargic' mouse and propose the possibility that a common mechanism may account for immunologic deficiencies in several types of mutant mice.

Animals↗
PubMed1977

One hundred patients with acute leukemia treated by chemotherapy, total body irradiation, and allogeneic marrow transplantation.

One hundred patients, 54 with acute myelogenous leukemia (AML) and 46 with acute lymphoblastic leukemia (ALL), considered to be in the end stages of their disease, after combination chemotherapy were treated by marrow transplantation. All patients were given a marrow graft from an HLA-identical sibling after receiving 1000-rad total body irradiation (TBI). One group of 43 patients was given cyclophosphamide (CY), 60 mg/kg on each of 2 days, 5 and 4 days before TBI. In a second group of 31 patients, additional chemotherapy was given before CY and TBI. In a third group of 19 patients, BCNU was given before CY and TBI. A fourth group of 7 patients received other chemotherapy regimens before TBI. Six patients died 3-17 days after marrow infusion without evidence of engraftment. Ninety-four patients were engrafted and only one patient rejected the graft. Thirteen patients are alive with a marrow graft, on no maintenance antileukemic therapy, and without recurrent leukemia 1-4 1/2 yr after transplantation. Three have chronic graft-versus-host disease (GVHD). Four patients are alive 1 1/2 - 3 1/2 yr after grafting but have had a relapse of their leukemia. Of 93 evaluable patients, 19 did not develop GVHD and 24 developed very mild GVHD. Fifty patients developed moderate to severe GVHD, and 40 of these were treated with antithymocyte globulin. Interstitial pneumonia occurred in 54 patients and was the primary cause of death in 34. Interstitial pneumonia often occurred in association with GVHD and the most common etiologic agent was cytomegalovirus. A total of 31 patients have had a relapse of leukemia. There was no definite correlation between relapse of leukemia and the presence or absence of GVHD. The relapse rate appeared to be relatively constant over the first 2 yr and was extremely low after that time. Neither survival nor leukemic relapse appeared to be influenced by the type of leukemia nor by the preparative chemotherapy regimen given before TBI. Patients in fair clinical condition at the time of transplantation showed significantly longer survival times than patients in poor condition (p = 0.001). This observation, coupled with the observation that some patients may be cured of their disease, indicates that marrow transplantation should now be undertaken earlier in the management of patients with acute leukemia who have an HLA-matched sibling marrow donor.

Antilymphocyte Serum↗