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Biomedical subjects

G Goldstein

Publications and source records attributed to G Goldstein.

At least 37 records · Page 2Linked to original sources
PubMed2000

Elevated plasma thymopoietin associated with therapeutic nonresponsiveness in major depression.

BACKGROUND: Stress predisposes to major depression, and hyperactivity of the stress-activated hypothalamic-pituitary-adrenal (HPA) axis occurs in this disease. Thymopentin, an active fragment of thymopoietin (TP), reduces endocrine and behavioral responses to experimental stress, possibly by lowering plasma TP (pTP) levels. METHODS: Plasma TP and the HPA hormones arginine vasopressin (pAVP), adrenocorticotropic hormone (pACTH), and plasma cortisol (pCORT) were measured in 21 untreated depressed patients and 21 matched control subjects. Clinical responses to antidepressants were evaluated in 17 depressed patients. RESULTS: Plasma TP was elevated in depression (p < .002), with in 8 out of 21 (38%) depressed patients having significant elevations (p < .03). For 17 patients whose antidepressant responses were evaluated, nonresponsiveness occurred in 6 out of 7 (86%) with elevated pTP (>7.5 pg/mL) versus 3 out of 10 (30%) with normal pTP (p < .05). CONCLUSIONS: The significant association of elevated pTP with nonresponsiveness to antidepressant drugs may signify a distinct pathogenesis for the depression of patients with elevated pTP.

Adrenocorticotropic Hormone↗
PubMed2000

Minimization of chronic plasma viremia in rhesus macaques immunized with synthetic HIV-1 Tat peptides and infected with a chimeric simian/human immunodeficiency virus (SHIV33).

HIV-1 Tat protein activates resting cells, rendering them permissive for viral replication. Replication of HIV-1 in vitro is enhanced by intercellular passage of Tat protein and inhibited by anti-Tat antibodies. Tat dependence of HIV-1 replication in vivo during acute, chronic asymptomatic and AIDS stages of infection was assessed by comparisons of plasma viremia in Tat-immunized or control monkeys challenged with SHIV(33) or SHIV(33A). Chronic plasma viremia became undetectable or minimized in Tat-immunized asymptomatic SHIV(33)-infected monkeys (p<0.008) while the high viral loads of acute infection or SHIV(33A)-induced simian AIDS were unaffected by Tat immunization. Active or passive immunotherapies targeting Tat provide potential approaches to controlling chronic HIV-1 viremia and preventing AIDS.

Amino Acid Sequence↗
PubMed2000

Influence of haloperidol on the relationship of frontal lobe function to psychomotor poverty and disorganization syndromes.

The aim of the study was to examine effects of haloperidol on the relationships between neuropsychological measures of frontal lobe functioning and the schizophrenia syndromes of psychomotor poverty and disorganization. Twenty-one participants with schizophrenia were initially evaluated when clinically stable and chronically treated with haloperidol, and 19 were evaluated again after a 3-week haloperidol-free period. Participants were evaluated with the Trail Making Test, the Wisconsin Card Sorting Test, the Purdue Pegboard, and psychiatric rating scales at each evaluation. There were significant correlations between schizophrenia syndromes and the tests sensitive to frontal lobe function when participants were medicated but not when drug-free. No significant changes in symptom severity or motor function occurred from the medication to the medication-free evaluation. The results indicate that haloperidol mediates the relationship between tests sensitive to frontal lobe function and the schizophrenia syndromes of psychomotor poverty and disorganization. This mediation effect was not attributable to changes in overall symptom severity or motor function.

Adult↗
PubMed2000

Responses to Light and Water Availability of Four Invasive Melastomataceae in the Hawaiian Islands.

Plant invasion by Neotropical Melastomataceae is prominent in Hawaii. To understand life history traits of four successful invasive Melastomataceae, two shade-intolerant herbs (Arthrostema ciliatum and Tibouchina herbacea) and two shade-tolerant woody species (Clidemia hirta, a shrub, and Miconia calvescens, a tree) were subjected to three light levels and two watering regimes in a greenhouse. Plant height, leaf number and area, biomass allocation, relative growth rate (RGR), carbon assimilation (A), leaf nutrient content, leaf construction costs (CC), specific leaf mass (SLM), and leaf spectral properties were determined at the end of the experimental period. Plant size, total biomass, RGR, A, CC, and SLM decreased, whereas leaf light transmittance and leaf N increased under low light in all species. The effects of water stress were weaker than light-stress effects. Relative growth rate of herbs grown in sun and partial shade (0.046 and 0.033 g g-1 d-1, respectively) was higher than in the woody species (0.027 and 0.020 g g-1 d-1). Woody species allocated more biomass to leaf production than herbs, which allocated more biomass to stem production. Shade increased allocation of biomass to leaves, and water stress increased the root-shoot ratio in all species. Partial shade increased leaf area ratios more in the herbs (140%) than in woody species (68%). Miconia calvescens and C. hirta had higher leaf absorbance (92%) than both herbs (79%). Maximum A under all light treatments was similar in all species, and there was substantial acclimation to the different light levels. Leaf construction cost was higher in the apparently long-lived leaves of the woody species. Relative growth rate, carbon allocation, and SLM showed larger changes to light and water stress than A and related photosynthetic parameters. All species showed responses qualitatively similar to those of other tropical species including the high acclimation potential to light, but the herbs exhibited the largest quantitative responses. When compared with a large group of native species, the four melastomes appear to be better suited to capture and use light, which is consistent with their rapid spread in mesic and disturbed Hawaiian environments.

Journal Article↗
PubMed2000

Morphological and Physiological Responses of Hawaiian Hibiscus tiliaceus Populations to Light and Salinity.

Hibiscus tiliaceus (Hau) is a pantropical mangrove associate that usually occurs in coastal ecosystems where substrate salinity is relatively high, but it also inhabits upland habitats in Hawaii. Cuttings from three populations on the island of Oahu, Hawaii, were collected and grown in the glasshouse under two levels of substrate salinity (0 and 335 mOsm kg-1) and three light treatments (0%, 50%, and 90% shade). Photosynthetic gas exchange, biomass allocation, and accumulation were studied in relation to salinity and light. Salinity reduced net CO2 assimilation in the upland population but had no effect or stimulated photosynthesis in the coastal populations, whereas increasing salinity decreased stomatal conductance in all populations and therefore increased water-use efficiency. The degree to which photosynthesis was inhibited by salinity was inversely proportional to the salinity of the source population, indicating a loss of salinity tolerance in upland plants. Light had a stronger effect on leaf area ratio (LAR) and leaf mass per area (LMA), whereas salinity had a stronger effect on leaf water content, internode length, and plant biomass. Salinity reduced total new biomass by 58%, 50%, and 34% in full sun, 50% shade, and 90% shade, respectively, but this response did not differ between populations. Salinity reduced the photosynthesis, but not growth, of upland plants because increased allocation to photosynthetic tissue increased LAR to compensate for inhibition of photosynthesis by salinity.

Journal Article↗
PubMed2000

Supercooling Capacity Increases from Sea Level to Tree Line in the Hawaiian Tree Species Metrosideros polymorpha.

Population-specific differences in the freezing resistance of Metrosideros polymorpha leaves were studied along an elevational gradient from sea level to tree line (located at ca. 2500 m above sea level) on the east flank of the Mauna Loa volcano in Hawaii. In addition, we also studied 8-yr-old saplings grown in a common garden from seeds collected from the same field populations. Leaves of low-elevation field plants exhibited damage at -2 degrees C, before the onset of ice formation, which occurred at -5.7 degrees C. Leaves of high-elevation plants exhibited damage at ca. -8.5 degrees C, concurrent with ice formation in the leaf tissue, which is typical of plants that avoid freezing in their natural environment by supercooling. Nuclear magnetic resonance studies revealed that water molecules of both extra- and intracellular leaf water fractions from high-elevation plants had restricted mobility, which is consistent with their low water content and their high levels of osmotically active solutes. Decreased mobility of water molecules may delay ice nucleation and/or ice growth and may therefore enhance the ability of plant tissues to supercool. Leaf traits that correlated with specific differences in supercooling capacity were in part genetically determined and in part environmentally induced. Evidence indicated that lower apoplastic water content and smaller intercellular spaces were associated with the larger supercooling capacity of the plant's foliage at tree line. The irreversible tissue-damage temperature decreased by ca. 7 degrees C from sea level to tree line in leaves of field populations. However, this decrease appears to be only large enough to allow M. polymorpha trees to avoid leaf tissue damage from freezing up to a level of ca. 2500 m elevation, which is also the current tree line location on the east flank of Mauna Loa. The limited freezing resistance of M. polymorpha leaves may be partially responsible for the occurrence of tree line at a relatively low elevation in Hawaii compared with continental tree lines, which can be up to 1500 m higher. If the elevation of tree line is influenced by the inability of M. polymorpha leaves to supercool to lower subzero temperatures, then it will be the first example that freezing damage resulting from limited supercooling capacity can be a factor in tree line formation.

Journal Article↗
PubMed2000

Length and number of hospitalizations in two cohorts of veterans with chronic schizophrenia.

Two cohorts of male veteran patients with schizophrenia were compared on several clinical and demographic measures. The first cohort, hospitalized in one of two Veterans Affairs hospitals between 1965 and 1975, consisted largely of Korean-era veterans. The second cohort, hospitalized between 1991 and 1994, were largely Vietnam-era veterans. Although treatment and management of patients with schizophrenia differed during the two eras and the second cohort had a significantly higher mean number of hospitalizations than the first, the two cohorts did not differ in total time hospitalized. The finding suggests the need to improve methods for relapse prevention.

Adult↗
PubMed2000

Neurologic examination abnormalities in schizophrenia with and without a history of alcoholism.

OBJECTIVE: The current investigation examines the impact of a past history of alcoholism on neurologic examination abnormalities in schizophrenia (SZ). BACKGROUND: Individuals with SZ have a high rate of comorbid alcohol use disorders (AUDs), but relatively little is known about the potential adverse consequences of alcoholism for neuropsychological and neurologic functioning in SZ. Recent evidence suggests consistent but subtle neurocognitive differences between groups, with more prominent differences in neurologic examination abnormalities. METHOD: Thirty-three male patients with SZ or SZ/AUDs were evaluated using a modified Neurologic Evaluation Scale (NES) and ratings for positive and negative symptoms. RESULTS: The SZ/AUD group exhibited a greater impairment in the Cognitive-Perceptual factor of the Neurologic Evaluation Scale. Greater impairment in the tandem-Romberg factor or in motor items was not found, nor were groups different based on positive or negative symptoms. CONCLUSIONS: A history of alcoholism in SZ is associated with greater overall neurologic impairment, particularly in the area of cognitive-perceptual dysfunction, an area often found to be impaired in patients with schizophrenia without alcoholism.

Adult↗
PubMed2000

[Treatment of adults with acute lymphoblastic leukemia--results at the Sheba Medical Center, Tel-Hashomer, 1977-1988].

Acute lymphoblastic leukemia (ALL) is a malignant disease whose incidence is relatively low among adults, unlike in children. Adults with ALL have a lower rate of long-term disease-free survival. During the last 20 years, a German multicenter group has shown that their protocols have achieved good results in adults ALL. We reviewed the medical records of 35 ALL patients, aged 19-63 years, whom we treated with these protocols (1988-1997). The remission rate was 94%. At a median follow-up of 46 months the 2-year overall survival was 54% and the disease-free survival was 94%. Although 2 patients died of bone marrow transplant complications, no death was directly associated with drug toxicity. The main grade 3 or 4 side effects (WHO classification) were neutropenia (91%), thrombocytopenia (71%) and anemia (71%). With there protocols we achieved high overall and disease-free survival rates, especially in comparison with other reports. Despite the high rate of severe treatment toxicity, there were no fatalities directly related to treatment. These results emphasize the need to concentrate treatment of adult ALL patients in large medical centers with expertise in the use of the complicated treatment protocols required.

Adult↗
PubMed1999

Lateralized brain dysfunction in schizophrenia: a comparison with patients with lateralized structural lesions.

A comparison was made among participants with schizophrenia and those with structural lateralized or diffuse brain damage in order to determine the extent to which the cognitive profile of the schizophrenia sample resembled the profiles obtained from patients with left-hemisphere, right-hemisphere, and diffuse brain damage. The Halstead-Reitan Neuropsychological Battery was used as the testing procedure. The data were subjected to discriminant analysis in order to obtain frequencies of predicted classification of the participants with schizophrenia into schizophrenia, left-hemisphere, right-hemisphere, and diffuse groups. Half of the participants with schizophrenia were classified into the schizophrenia group. The other half was evenly distributed across the left-hemisphere, right-hemisphere, and diffuse brain damage groups. There was not a disproportionately large number of participants classified into the left-hemisphere group. Comparisons among these four predicted groups were accomplished for each of the Halstead-Reitan Battery measures using one-way analysis of variance. The comparison of the subtest scores among the predicted groups indicated that the patients classified into the left-hemisphere group were characterized by a pattern of language dysfunction thought to be developmental in nature, and an abnormal lack of asymmetry in tapping speed favoring the right hand.

Adult↗
PubMed1999

MRI volumes of amygdala and hippocampus in non-mentally retarded autistic adolescents and adults.

OBJECTIVE: To determine whether volumes of hippocampus and amygdala are abnormal in people with autism. BACKGROUND: Neuropathologic studies of the limbic system in autism have found decreased neuronal size, increased neuronal packing density, and decreased complexity of dendritic arbors in hippocampus, amygdala, and other limbic structures. These findings are suggestive of a developmental curtailment in the maturation of the neurons and neuropil. METHODS: Measurement of hippocampus, amygdala, and total brain volumes from 1.5-mm coronal, spoiled gradient-recalled echo MRI scans in 14 non-mentally retarded autistic male adolescents and young adults and 14 individually matched, healthy community volunteers. RESULTS: Amygdala volume was significantly smaller in the autistic subjects, both with (p = 0.006) and without (p = 0.01) correcting for total brain volume. Total brain volume and absolute hippocampal volume did not differ significantly between groups, but hippocampal volume, when corrected for total brain volume, was significantly reduced (p = 0.04) in the autistic subjects. CONCLUSIONS: There is a reduction in the volume of amygdala and hippocampus in people with autism, particularly in relation to total brain volume. The histopathology of autism suggests that these volume reductions are related to a reduction in dendritic tree and neuropil development, and likely reflect the underdevelopment of the neural connections of limbic structures with other parts of the brain, particularly cerebral cortex.

Adolescent↗
PubMed1999

Molecular mechanisms of lead neurotoxicity.

Epidemiological studies have shown a strong relationship between the level of lead in blood and bone as assessed by performance on IQ tests and other psychometric tests. Approximately 1 out of 10 children in the United States have blood lead levels above 10 microg/dl, which has been established as the level of concern. Studies on experimental animals exposed to lead after birth have shown learning deficits at similar blood lead levels. Since learning requires the remodeling of synapses in the brain, lead may specifically affect synaptic transmission. Although the molecular targets for lead are unknown, a vast amount of evidence accumulated over many years has shown that lead disrupts processes that are regulated by calcium. Our laboratory has been studying the effect of lead on protein kinase C, a family of isozymes some of which require calcium for activity. We and others have shown that picomolar concentrations of lead can replace micromolar concentrations of calcium in a protein kinase C enzyme assay. Furthermore, lead activates protein kinase C in intact cells and induces the expression of new genes by a mechanism dependent on protein kinase C. We propose that the learning deficits caused by lead are due to events regulated by protein kinase C that most likely occur at the synapse.

Animals↗
PubMed1999

Neurocognitive dysfunction in patients diagnosed with schizophrenia and alcoholism.

The authors administered the Halstead-Reitan Neuropsychological Test Battery to schizophrenic groups with (n = 54) and without (n = 217) coexisting alcoholism, nonschizophrenic groups with alcoholism (n = 231), and a patient comparison group (n = 145) to determine the extent of additive cognitive impairment in schizophrenia associated with alcoholism and to compare cognitive function in alcoholism and schizophrenia. The additive effects of alcoholism on cognitive dysfunction in schizophrenia were subtle but were consistently identifiable. Cognitive dysfunction in alcoholism was less severe than in schizophrenia with or without alcoholism. The magnitude of additive effects of alcoholism on cognitive dysfunction in schizophrenia was age related with a significant interaction between age and presence or absence of alcoholism on a global index of cognitive dysfunction.

Adult↗
PubMed1999

Is the Halstead Category Test a multidimensional instrument?

Factor structure of the Halstead Category Test was evaluated in patients with schizophrenia, heterogeneous forms of brain damage, and patient controls using confirmatory factor analysis. Analyses were performed including and excluding subtests 1 and 2. In the first analysis, a three-factor model was optimal, with subtests 1 and 2 loading on one factor (Counting), 3, 4, and 7 loading on a second factor (Spatial Positional Reasoning), and subtests 5 and 6 loading on a third factor (Proportional Reasoning). Excluding subtests 1 and 2, a two-factor solution was optimal consisting of the Spatial Positional (subtests 3 and 4) and Proportional Reasoning (subtests 5 and 6) factors, with subtest 7 loading on both factors. Optimal factor structures for the three groups were identical. Correlations between factor scores were similar among groups. Factor scores also correlated significantly (p <.01 ) with all of the other cognitive measures. It was concluded that the Category Test is a multidimensional procedure with factors associated in a general way with other cognitive abilities.

Adult↗
PubMed1999

Relations between cognitive and symptom profile heterogeneity in schizophrenia.

Although numerous studies have consistently revealed cognitive heterogeneity in schizophrenia, the relationships between such heterogeneity and clinical phenomenology are not clear. Clusters derived from cognitive heterogeneity studies may or may not be associated with symptom profile or severity of illness. The purpose of this study was to examine the relationship between cognitive heterogeneity and demographic and clinical phenomenological measures. We examined cognitive heterogeneity in schizophrenia by empirically deriving clusters of patients based upon WAIS-R subtest scores and then analyzed the way in which these clusters related to demographic and symptom variables and to DSM-III-R diagnostic subtypes. Four cognitive clusters were identified that were consistent with previous research. These clusters were differentiated on the basis of educational level and occupational status but not on the basis of symptom profile, severity, or DSM-III-R subtypes. Results suggest that cognitive measures are independent of severity of the disorder and phenomenological symptom presentation in these subgroups of schizophrenic patients.

Adult↗
PubMed1998

Confirmatory factor analysis of the WAIS-R in patients with schizophrenia.

Although factor scores are commonly used to interpret the Weschsler Adult Intelligence Scale--Revised (WAIS-R), the WAIS-R factor structure has not been investigated in patients with schizophrenia. We used confirmatory factor analysis (CFA) to examine five latent construct models in 169 males with schizophrenia. The WAIS-R standardization sample (ages 35-44; n = 250) was used as a comparison group. For both groups, all model fit indexes used to determine model adequacy supported models composed of Verbal Comprehension (VC), Perceptual Organization (PO) and Freedom from Distractibility (FFD) factors. However, the Digit Symbol subtest loaded on both the PO and FFD factors for patients with schizophrenia but only on the FFD factor for the WAIS-R standardization sample. Patients with schizophrenia performed significantly worse on the FFD and PO factors compared to the VC factor, reflecting the well-characterized attention and problem solving deficits associated with schizophrenia. Also, patients with schizophrenia performed significantly worse than the WAIS-R sample on all factors. These results provide support for the validity of the WAIS-R factors in patients with schizophrenia.

Adult↗