PubMed Health⌕ Search

Biomedical subjects

G Bryson

Publications and source records attributed to G Bryson.

At least 37 records · Page 2Linked to original sources
PubMed1998

The functional consequences of memory impairments on initial work performance in people with schizophrenia.

Exploring the link between cognitive impairments and domains of function is a new trend in schizophrenia research. This study reports on the association of verbal memory impairment and initial work function for a group of 87 individuals diagnosed with either schizophrenia or schizoaffective disorder. Multiple regression analyses were used to predict the degree of association between verbal memory variables and ratings on the Work Behavior Inventory (WBI) in the initial week of a vocational rehabilitation program. Results indicated that verbal memory scores predicted 20% of the WBI total score. Results also indicated strong relationships with the individual work domains of work habits and work quality and weaker relationships with the domains of cooperativeness and personal presentation. No significant relationship was found between verbal memory variables and social skills at the job site. Verbal memory impairment is discussed as a rate limiting factor in rehabilitation.

Adult↗
PubMed1998

Heterogeneity of CD44 expression among human B-cell subpopulations.

CD44 is a widely distributed cell surface glycoprotein that participates in a number of cellular adhesion and signal transduction processes. Germinal center B cells express very low levels of CD44, whereas their precursors and differentiation products express much higher levels. In immunofluorescence studies comparing 20 antibodies classified as being against the hematopoietic isoform of CD44, one antibody, A1G3, was unreactive with germinal center B cells, whereas the other antibodies showed low intensity but definite reactivity. Western blotting and sequential immunoprecipitation studies of lysates from density-separated lymphocyte fractions showed two bands that were differentially expressed and reacted differently with A1G3 compared with the other CD44 antibodies. These results suggest that germinal center B cells and non-germinal center B cells express different forms of CD44. Of 21 malignant B-cell populations examined, 5 showed reactivity with a "standard" CD44 reagent and significantly reduced reactivity with A1G3, while one sample showed the opposite pattern and the remainder were positive for both reagents. Of 10 cell lines studied, 5 were differentially stained by A1G3 and a standard CD44 antibody. PCR amplification of reverse transcribed mRNA from sorted human tonsil B-cell subpopulations and Southern blotting showed that B cells express a number of splice isoforms of CD44. These results demonstrate that B cells express multiple forms of CD44; both splice insert isoforms and variants distinguished by A1G3; the form of CD44 expressed depends on B-cell differentiation state.

Antibodies, Monoclonal↗
PubMed1998

Neurocognitive function and insight in schizophrenia: support for an association with impairments in executive function but not with impairments in global function.

It remains unclear how impaired insight and neurocognitive impairment are related to one another in schizophrenia. In order to examine this relationship, subjects with schizophrenia or schizoaffective disorder were classified as having 'impaired' (n=38) or 'unimpaired' (n=43) insight based on their insight rating on the Positive and Negative Syndrome Scale (PANSS). Their performance on neuropsychological tests of global function, executive function, memory and vigilance was then compared. Multivariate analyses followed by Scheffe tests indicated that subjects with impaired insight performed less well on the Wisconsin Card Sorting Test, demonstrating poorer abstract flexibility and heightened perseveration. No differences were found between the groups with regard to global cognitive function, memory or vigilance. This suggests that insight is closely linked to deficits in executive function, and that it may be associated with the compromise of frontal lobe function.

Adult↗
PubMed1997

Positive and negative affect recognition in schizophrenia: a comparison with substance abuse and normal control subjects.

This study had three aims: to compare a schizophrenia sample (n = 50) with a substance abuse (n = 25) and normal sample (n = 81) on affect recognition; to compare differences in their performance between positive and negative affect recognition; and to introduce a new videotape method of stimulus presentation. Subjects were asked to identify the predominant affect depicted in 21 5-10-s vignettes containing three trials of seven affect states. Results demonstrate significant group differences: normal subjects scored in the normal or mild range, substance abuse (s/a) subjects scored in the mild and moderate ranges, and the schizophrenia sample scored predominantly in the moderate to severe ranges. Accuracies were 92.3% for the normal sample, 77.2 for the s/a sample and 64.8 for the schizophrenia sample. Response dispersions were 97.6% for the schizophrenia group, 69% for the s/a sample and 38% in the normal sample. A repeated measures ANOVA revealed a group by type of affect interaction with schizophrenia subjects showing far greater differential impairment on negative affect recognition. Difficulty of item did not contribute to this difference. Test-retest reliability at 5 months for this new method was r = 0.76, and stability of categorization was very high over 5 months (weighted kappa = 0.93). These affect recognition deficits in schizophrenia are discussed as they relate to lateralization of brain function, high EE families, social skills impairment and implications for rehabilitation services.

Adult↗
PubMed1997

Affect recognition in schizophrenia: a function of global impairment or a specific cognitive deficit.

To investigate cognitive variables related to affect recognition in schizophrenia, 63 subjects with DSM-III-R diagnoses of schizophrenia or schizoaffective disorder were administered a test battery which included the Bell-Lysaker Emotion Recognition Task (BLERT), Wisconsin Card Sorting Test (WCST), Wechsler Memory (WMS-R) and Adult Intelligence Scales (WAIS-R), Hopkins Verbal Learning Test, Gorham's Proverbs, and Continuous Performance Task (CPT). Coefficients revealed a moderate relationship between emotion recognition and WCST and CPT but no significant relationship with other test variables. Multiple regression analysis demonstrated that approximately one-third of the variance in BLERT scores could be explained by cognitive variables including the Digit Symbol Subtest, CPT, and Hopkins Verbal Learning Test. Other analyses demonstrated that subjects with moderate to severe affect recognition impairment had more perseverative errors, had fewer complete categories on the WCST and had more errors on the CPT. However, there were no significant differences on global measures of impairment such as WAIS-R IQs and Digit Symbol Substitution Test. The discussion focuses on deficits in affect recognition as a distinct feature which contributes to the heterogeneity of the disorder.

Adult↗
PubMed1997

Wisconsin Card Sorting Test dimensions in schizophrenia: factorial, predictive, and divergent validity.

This study explored the factor structure of the Wisconsin Card Sorting Test (WCST). Scores from 197 participants with schizophrenia or schizoaffective disorder were subjected to an exploratory factor analysis that yielded three factors: Perseveration, Nonperseverative Error, and Inefficient Sorting. Comparison with two previous factor analyses revealed remarkable factorial invariance. Correlations with subject and illness characteristics, symptom dimensions, and work performance demonstrated predictive and divergent validity for the three factors. However, a representative item from each factor yielded similar correlations with very little loss of power suggesting that the factors are composed of highly redundant items. When data reduction is necessary, schizophrenia researchers are justified in using three variables: perseverative error, nonperseverative error, and failure to maintain set, to represent WCST performance.

Adult↗
PubMed1995

Edrophonium requirements for reversal of deep neuromuscular block following infusion of mivacurium.

Mivacurium is a new non-depolarizing muscle relaxant consisting of three stereoisomers. The two active isomers (cis-trans and trans-trans) undergo rapid metabolism by plasma cholinesterase (t1/2 beta < 2 min). Due to its rapid elimination, the need for reversal of mivacurium-induced neuromuscular block is controversial, and to date there have been no studies evaluating reversal of deep blocks. The object of the current investigation was to establish the lowest effective dose of edrophonium required to reverse deep mivacurium-induced neuromuscular block. One hundred ASA Class I and II patients undergoing outpatient surgery in two teaching institutions were studied in this randomized, placebo-controlled double-blind trial. Under balanced propofol/nitrous oxide/alfentanil anaesthesia, a continuous infusion of mivacurium was adjusted to maintain between 5-10% of control T1 amplitude. Upon completion of surgery, neuromuscular block was reversed by injecting normal saline (Group PLAC), edrophonium 0.125 mg.kg-1 (Group EDR-1), 0.25 mg.kg-1 (Group EDR-2), or 0.50 mg.kg-1 (Group EDR-3), in addition to a corresponding dose of atropine. Spontaneous recovery, from a T1 response of < 10% to a TOF ratio > or = 0.7, required 13.5 +/- 2.6 min (PLAC Group). In comparison, patients in the EDR-1 group required 9.2 +/- 2.6 min (P < 0.01). Higher doses of edrophonium conferred no advantage. Four patients (4%) had not achieved a TOF ratio of > or = 70%, 20 min after reversal, and required additional edrophonium. Two patients (PLAC group), had dibucaine numbers and cholinesterase levels consistent with an EUEA genotype, whereas the two patients with delayed recovery in the EDR-1 group had characteristics of a normal genotype. We conclude that a very low dose of edrophonium (0.125 mg.kg-1) hastens reversal of deep mivacurium-induced neuromuscular block by approximately four minutes, and that edrophonium doses exceeding 0.125 mg.kg-1 provide no additional benefit. Heterozygous patients with atypical plasma cholinesterase levels, as well as certain individuals with normal dibucaine numbers and plasma cholinesterase activity, are at risk for prolonged neuromuscular block, but the block is easily reversed with edrophonium.

Adjuvants, Anesthesia↗
PubMed1994

Insight and psychosocial treatment compliance in schizophrenia.

Research has suggested that poor insight in patients with schizophrenia is associated with poorer medication compliance and heightened levels of psychopathology. This study examined the relationship of insight to compliance with a work rehabilitation program and with levels of psychopathology and psychosocial functioning. Poor insight was found to be positively associated with fewer weeks of participation and with poorer social skills and personal presentation in the fifth week of work. Poor insight was also associated with cognitive disorganization and a lower intelligence quotient, but not with heightened levels of psychopathology. Results suggest that poor insight may predict noncompliance with psychosocial treatment and may be related to a constellation of cognitive deficits.

Adult↗
PubMed1991

Prognostic importance of cellular DNA content in head-and-neck squamous-cell cancers. A comparison of retrospective and prospective series.

Flow cytometric DNA-ploidy measurements were performed on formalin-fixed tumour specimens from 172 patients with squamous-cell cancers (SCCs) of the head and neck region. One hundred and two samples were chosen retrospectively and a further 70 consecutive patients were analysed prospectively in order to assess the prognostic significance of DNA ploidy and DNA index (DI). There were no statistically significant differences between retrospective and prospective groups in regard to age, sex, TNM stage, ploidy or DI. Sixty-seven percent of patients were aneuploid (65% retrospective; 71% prospective). The proportion of aneuploid tumours was significantly higher among poorly differentiated tumours. Survival analysis using Cox multivariate regression modelling revealed that DNA aneuploidy and increasing DI were significant independent prognostic factors for both relapse-free and overall survival. The relapse and death rates among aneuploid subjects were approximately 3 times as high as those for diploid subjects. Patients with a DI greater than 2.11 (hypertetraploidy) experienced a 6.6-fold higher death rate than diploid subjects. These results provide strong support for the incorporation of DNA ploidy profiles into the clinical management of patients with head and neck cancer.

Adult↗
PubMed1982

Tissue reaction to and fate of parenterally administered titanium dioxide. I. The intraperitoneal site in male Marsh-Buffalo mice.

In 32 male Marsh-Buffalo mice each receiving a saline suspension of 25 mg TiO2 intraperitoneally, four neoplasms appeared over the 18-month experimental period. During this time, four neoplasms appeared in 30 control mice receiving isotonic saline by the same injection route. A nonsignificant association of tumorigenesis with experimental treatment indicated a lack of carcinogenic potential for TiO2 and is discussed in terms of the local tissue reaction in the mice that received the TiO2. Focal deposits of dose material rather than a diffuse distribution were found on the intraperitoneal wall and muscles as well as the gut. In some instances, TiO2 had migrated from the initial injection site. For the most part, no foreign-body reaction to TiO2 involving the presence of macrophages or characteristic capsular connective tissue formation was demonstrated, although a dose deposit attached to the peritoneum by a transparent membrane was observed. In one mouse, chronic myositis developed in muscle tissue containing a large amount of dose material.

Animals↗
PubMed1981

Long-term estrogenization in mammals. IV. Body, adrenal, and testes weights; polydipsia; food intake; vasopressin administration; and serum corticosterone levels in estrogenized male Evans rats.

In three experiments, the initial body weight losses after estrogenization were maintained or lagged the weight gains of the controls by the same amount over 61, 138, and 336 days, respectively. The mean serum corticosterone level of the controls was 56% that of the estrogenized rats 341 days after estrogenization. Water consumption (mg/kg b.w.) approximated 150% that of the controls several weeks following estrogenization, remaining elevated until the end of the experiment. Estrogen treatment produced a higher level of water intake in a few rats similar to that previously observed for mice. During the experimental period for water measurement, food consumption (g/kg b.w.) approximated 115% that of the controls. Gnawing and food-spilling behavior was observed in some of the estrogenized rats. Following vasopressin administration, food intake was lowered the first and second days in one estrogenized group; water intake was lowered the first day in the three control and estrogenized groups. In contrast to studies with Marsh mice, estrogenization did not produce bladder damage in Evans rats, but two showed tubular calcification in the kidneys.

Adrenal Glands↗
PubMed1981

Effects of adrenocortical stress responses and metabolic functions during and after long-term administration of dexamethasone to adult Evans-Long rats.

During the last 75 days of a 130-day period of daily ip. administration of dexamethasone (DEX) sodium phosphate to adult female Evans-Long rats, mean body weight stabilized 20% below that of the controls, returning to the comparison-control level by the 64th day after the end of DEX treatment. Throughout the experiment, all animals received Purina Laboratory Chow, tap water, and a 0.7 M NaCl solution ad libitum. With DEX dosage, daily total fluid intake means determined weekly were consistently greater than the control values. There were 11 instances of increased saline intake also accompanied by significant increases in daily total fluid intake, but these did not establish salt dependency. Plasma corticosterone levels during DEX treatment were decreased significantly, but the DEX group was still responsive to stress; a significant within-subjects correlation, seen only in this group, between low- and high-stress corticosterone levels suggests that DEX selectively suppressed stress-release factors. Mean corticosterone levels of the DEX group sampled under conditions of increased stress did not exceed those for low-stress sampling of the controls. Following a recovery period after termination of DEX dosage, corticosterone levels were the same for both groups sampled under similar stress conditions and were not correlated with stress levels or with adrenal weights in either group.

Adrenal Cortex↗
PubMed1980

Long-term estrogenization in mammals. II. Environmental influences of housing conditions upon estrogen-induced polydipsia and food intake in Marsh mice.

Estrogen-induced polydipsia was influenced by environmental conditions in which Marsh mice were housed in plastic cages with bedding or in metal cages having grilled floors and no bedding. Increases in this polydipsia with metal-cage housing were reversed upon return to plastic. The increases over controls as ml/kg body weight ranged from 40 to 250%. After an initial fall in food consumption following estrogenization, controls and estrogenized mice consumed nearly the same amount of food/mouse but 10% more for the estrogenized mice on a g/kg body-weight basis. Increased food consumption for controls and estrogenized mice following the change from plastic to metal cages was attributed to compensation for increased loss of body heat. Whether in plastic or metal cages, core temperatures of controls were higher than those of estrogenized mice; both groups had relatively higher temperatures in the metal cages. The older mice in metal cages developed a gnawing pattern wasting food. In five experiments with males, body-weight losses following estrogenization were maintained 43 to 70 days but recovered in 2 of 4 experiments with females under comparable conditions.

Animals↗
PubMed1980

Long-term estrogenization in mammals. III. Vasopressin and calcitonin in the regulation of water intake in estrogenized Marsh mice.

During the increasing polydipsia following estrogenization, vasopressin administration produced increasing antidiuretic effects demonstrating that renal receptor sites remained functional. The antidiuretic effect in the controls was less than in the estrogenized mice. An antidiuretic effect with calcitonin was demonstrated in the controls and in one experiment in the estrogenized mice but not in another with a high standard error for water intake. A decrease in food intake for the estrogenized mice the first day after vasopressin administration was of doubtful significance. A significant decrease in food intake in the control and estrogenized mice was demonstrated for calcitonin. The effects of the vehicles used for hormone administration on water and food intake necessitated a correction in some instances. As previously observed in estrogenized mice, bladder pathology preceded kidney pathology in additional experiments.

Animals↗
PubMed1979

Long-term estrogenization in mammals. I. Histopathology of kidney, bladder, adrenals, and gonads; polydipsia; body weight; and serum levels of corticosterone and testosterone in estrogenized Marsh mice.

Single, sublethal, long-acting doses of estrone or estradiol cypionate produced the following histologic, behavioral, and blood chemistry effects in Marsh mice: (a) Bladder pathology developed following estrogen-induced polydipsia but was not consistently associated with kidney damage. (b) This polydipsia was more intense (a maximum of 250% over control intake) when the housing was in metal cages with floor screens than in plastic cages with bedding. Water intake of control mice was unaffected by housing changes. (c) Comparing litter-mate 2.5-month-old males and females, body weight loss following estrogen administration was transient with the females. With males, initial weight losses as compared with weight gains in the controls were demonstrated over a 20-week period. (d) Estrogenization markedly increased corticosterone and decreased testosterone serum levels with a significant negative correlation for these levels in the estrogenized mice. A significant positive correlation was also observed between testosterone levels and testis weights in the estrogenized mice.

Adrenal Glands↗
PubMed1979

Short- and long-term effects of graduated doses of DL-6-OH-DOPA upon marsh mice.

The lethal effects in Marsh mice for a range of DL-6-OH-DOPA levels were ascertained and exceeded those previously reported for 6-OH-DA under comparable conditions. The addition of vitamin "C" to the 6-OH-DOPA solution given intraperitoneally increased the lethal effect, as did the intraperitionel route of injection over that of the subcutaneous. Increased water consumption developed the fourth day for those surviving toxic levels of 6-OH-DOPA given subcutaneously as compared with controls. For all mice initially surviving administration of 6-OH-DOPA, tumorigenesis and long-term survival were of the same order as that of the controls. The toxicity of 6-OH-DOPA relating to ferric heme formation more likely involves metmyoglobin than methemoglobin. The combination of direct damage to sympathetic adrenergic cardiac innervation and metmyoglobin formation appears sufficient to account for the lethal effects of 6-OH-DOPA.

Age Factors↗