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D Weiss

Publications and source records attributed to D Weiss.

At least 55 records · Page 3Linked to original sources
PubMed2000

Department of Veterans Affairs Cooperative Studies Program genetic linkage study of schizophrenia: ascertainment methods and sample description.

To help clarify the genetics of schizophrenia, the Department of Veterans Affairs Cooperative Studies Program has completed data collection for a genetic linkage study of schizophrenia. This article describes the methodological details of the data collection. Subsequent articles will describe the results of our genome scan, which is now in progress. The data collection protocol included the Diagnostic Interview for Genetic Studies, the Family Interview for Genetic Studies, a review of medical records, and the collection of blood for transformation into lymphoblast cell lines. Among relatives of schizophrenic probands, we assessed auditory attention and verbal memory with neuropsychological tests. Among the 166 families ascertained for the study, 143 had a single affected sib-pair, 17 had three affected siblings, one had five affected siblings and five had two sets of affected siblings. There was a total of 216 affected sib-pairs in these families. Using the n-1 rule, these families contain 188 independent affected sib-pairs.

Adult↗
PubMed2000

Weak localization in antidot arrays: signature of classical chaos

We study, experimentally and theoretically, quantum weak localization (WL) corrections to the classical magnetoconductivity of two-dimensional ballistic systems with regular and disordered patterns of dense antidots. We analyze the observed temperature and flux dependences of the WL using different theoretical models for the chaotic dynamics and dephasing rates. The measured resistivity curves, which deviate from those of diffusive systems, reflect chaotic motion and correlations in the classical dynamics of electrons in the antidot landscape. The results support the significance of the Ehrenfest time as a relevant time scale for ballistic WL.

Journal Article↗
PubMed2000

Computed tomography of cryogenic biological specimens based on X-ray microscopic images.

Soft X-ray microscopy employs the photoelectric absorption contrast between water and protein in the 2.34-4.38 nm wavelength region to visualize protein structures down to 30 nm size without any staining methods. Due to the large depth of focus of the Fresnel zone plates used as X-ray objectives, computed tomography based on the X-ray microscopic images can be used to reconstruct the local linear absorption coefficient inside the three-dimensional specimen volume. High-resolution X-ray images require a high specimen radiation dose, and a series of images taken at different viewing angles is needed for computed tomography. Therefore, cryo microscopy is necessary to preserve the structural integrity of hydrated biological specimens during image acquisition. The cryo transmission X-ray microscope at the electron storage ring BESSY I (Berlin) was used to obtain a tilt series of images of the frozen-hydrated green alga Chlamydomonas reinhardtii. The living specimens were inserted into borosilicate glass capillaries and, in this first experiment, rapidly cooled by plunging into liquid nitrogen. The capillary specimen holders allow image acquisition over the full angular range of 180 degrees. The reconstruction shows for the first time details down to 60 nm size inside a frozen-hydrated biological specimen and conveys a clear impression of the internal structures. This technique is expected to be applicable to a wide range of biological specimens, such as the cell nucleus. It offers the possibility of imaging the three-dimensional structure of hydrated biological specimens close to their natural living state.

Algorithms↗
PubMed2000

Refractory sprue syndrome with clonal intraepithelial lymphocytes evolving into overt enteropathy-type intestinal T-cell lymphoma.

INTRODUCTION: Recently, patients with refractory sprue have been shown to contain a clonal proliferation of phenotypically abnormal intraepithelial lymphocytes in their intestine. Whether this signifies early enteropathy-type intestinal T-cell lymphoma (EITCL) or a reactive condition is not clear. We report on a patient presenting with the findings of refractory sprue who subsequently developed overt EITCL. MATERIAL AND METHODS: Duodenal biopsies from 1997 (refractory sprue) and duodenal and jejunal biopsies from 1998 (intestinal T-cell lymphoma) were compared by immunohistochemistry and PCR for the detection of T-cell receptor (TCR)-gamma gene rearrangements. Clonal PCR products were sequenced. RESULTS: The duodenal biopsies from both 1997 and 1998 and the jejunal tumor biopsy showed villus atrophy and an increase of intraepithelial lymphocytes with an abnormal immunophenotype (CD3+, CD4-, CD8- and TCR-beta-). In all duodenal specimens including the one from 1997, and the jenunal tumor biopsy, an identical clonal amplificate was detected by enzymatic amplification of the TCR-gamma gene. CONCLUSION: These data suggest that refractory sprue containing a clonal proliferation of phenotypically abnormal intraepithelial lymphocytes may represent an early manifestation of EITCL. The detection of immunohistochemical negativity for several antigens normally found on intraepithelial lymphocytes such as CD8 or the TCR-beta chain in combination with clonal T-cell populations by PCR may be helpful in identifying refractory sprue with a malignant transformation.

CD3 Complex↗
PubMed2000

Role of inflammatory mediators in priming, activation, and deformability of bovine neutrophils.

OBJECTIVE: To determine the capacity of inflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), platelet-activating factor (PAF), lipopolysaccharide (LPS), and leukotoxin to prime, activate, or alter deformability of adult bovine neutrophils. SAMPLE POPULATION: Blood collected from 5 healthy adult Holstein cows. PROCEDURE: Isolated neutrophils or whole blood was incubated with TNF-alpha, IL-8, PAF, LPS, or leukotoxin, and neutrophil chemiluminescence, degranulation, deformability, shape change, CD11b expression, and size distribution was measured. RESULTS: Incubation with TNF-alpha, IL-8, PAF, and LPS primed neutrophils for oxygen radical release but caused minimal oxygen radical release by themselves. None of the inflammatory mediators induced degranulation. Incubation with TNF-alpha and PAF resulted in a decrease in neutrophil deformability and induced shape change in neutrophils. Incubation with PAF consistently resulted in an increase in neutrophil size as measured by use of flow cytometry. Only IL-8 caused an increase in expression of CD11b by neutrophils. CONCLUSIONS AND CLINICAL RELEVANCE: Inflammatory mediators tested had minimal effects on neutrophil oxygen radical production or degranulation but did prime neutrophils for oxygen radical production. Incubation with PAF and TNF-alpha caused a decrease in neutrophil deformability and altered neutrophil shape and size. Results of our study indicate that PAF- and TNF-alpha-induced changes in neutrophil deformability and size may cause integrin- and selectin-independent trapping of neutrophils in the lungs of cattle with pneumonic pasteurellosis.

Alkaline Phosphatase↗
PubMed2000

How to help your patients lose weight: current therapy for obesity.

Obesity is epidemic and dangerous. Weight loss is difficult but worth the effort. Although new weight-loss drugs are available, there are no magic bullets: to lose weight and keep it off, people must eat less and exercise more. This article presents a practical approach on how physicians can help their patients lose weight through diet, behavior modification, and adjunctive pharmacologic therapy. An appropriate initial goal is to lose 5% to 10% of one's baseline weight over 3 to 6 months. Drug therapy should not be used in isolation, but it can be an adjunct to diet, exercise, and behavior modification if a patient is committed and able to make necessary changes in eating and activity, and if the patient has a BMI of 30 or higher or a BMI greater than 27 with weight-related comorbid conditions. Anorectic therapy is unlikely to succeed and should be stopped if the patient does not lose at least 4 lb in the first 4 weeks of therapy. Orlistat is unlikely to be of benefit if patients do not lose at least 3% of their baseline weight by 12 weeks. Because obesity is a chronic disease, drug treatment should be continued indefinitely. The physician and patient must understand the intention to treat long-term. The weight loss plan devised should improve upon previous plans: for example, implementing a regular, convenient exercise program that had not been included in the past, or offering pharmacotherapy.

Anti-Obesity Agents↗
PubMed1999

Interdependence of peat and vegetation in a tropical peat swamp forest.

The visual uniformity of tropical peat swamp forest masks the considerable variation in forest structure that has evolved in response to differences and changes in peat characteristics over many millennia. Details are presented of forest structure and tree composition of the principal peat swamp forest types in the upper catchment of Sungai Sebangau, Central Kalimantan, Indonesia, in relation to thickness and hydrology of the peat. Consideration is given to data on peat geochemistry and age of peat that provide evidence of the ombrotrophic nature of this vast peatland and its mode of formation. The future sustainability of this ecosystem is predicted from information available on climate change and human impact in this region.

Carbon Radioisotopes↗
PubMed1999

A redox-dependent, G-protein-coupled phospholipase A of the plasma membrane is involved in the elicitation of alkaloid biosynthesis in Eschscholtzia californica.

In cultured cells of California poppy formation of benzophenanthridine alkaloids can be triggered by a yeast elicitor preparation independently of the hypersensitive reaction. A plasma membrane (PM) bound phospholipase A (PLA) is likely to play a role in the signalling process: PLA activity was detectable in individual cells, cell suspensions and PM vesicles with the fluorogenic phospholipid bis-BODIPY FL C11-PC and was sensitive to known inhibitors of PLA2. In microscopic assays, enzyme activity increased after elicitor contact of cells that were pretreated with non-saturating concentrations of PLA2 inhibitors. In PM vesicles a PLA2-like protein as well as G alpha- and G beta-proteins were detected immunologically. Anti-G alpha or anti-G beta antisera or mastoparan stimulated PLA activity thus indicating a G-protein-controlled enzyme. Elicitation of alkaloid production was sensitive to aristolochic acid and enhanced by PLA2 products such as lysophosphatidylcholine and linolenic acid. Pretreatment of the cells with the artificial electron acceptors hexabromoiridate(V) or ferricyanide(III) reversibly abolished the effect of subsequent elicitation and reduced the activity of PLA both in intact cells and in PM vesicles. It appears, therefore, that PLA2 is a point of interference of redox control with the signal path.

Alkaloids↗
PubMed1999

Testicular fine needle aspiration: the alternative method for sperm retrieval in non-obstructive azoospermia.

The objective of this prospective open study was to determine the feasibility of obtaining mature spermatozoa for intracytoplasmic sperm injection (ICSI) by testicular fine needle aspiration (TEFNA) in men diagnosed with non-obstructive azoospermia. TEFNA consisted of a mean of 15 punctures and aspirations in each testis, using 23 gauge butterfly needles, connected to a 20 ml syringe with an aspiration handle. Patients (n = 85) underwent 111 TEFNA cycles. Mature testicular spermatozoa were recovered in 65 (58.5%) cycles from 50 (58.8%) patients. The sperm recovery rate by testicular histology was 14 out of 29 (48.3%) in patients with Sertoli cell-only, 13 out of 28 (46.4%) in patients with maturation arrest, 19 out of 20 (95%) in patients with hypospermatogenesis, four out of six (66.6%) in patients with tubular hyalinization due to non-mosaic Klinefelter's syndrome. No spermatozoa were found in two cases with post-irradiation fibrosis. ICSI was performed in all 65 cycles. In 58 cycles in which only the husbands' spermatozoa were used, 406 mature oocytes were injected, and 154 (37.9%) were normally fertilized. Of the 143 embryos that developed (92.8%), 119 were transferred in 42 cycles resulting in 18 clinical pregnancies (42. 8%), with 31 gestational sacs, providing an implantation rate of 26%. One abortion of a singleton pregnancy occurred (5.6%). No major side-effects, such as haematoma or infection were recorded. In conclusion, we have found TEFNA to be efficient, easy to learn, safe and well tolerated by all patients. In our opinion, TEFNA should be considered the first choice whenever sperm recovery is attempted in patients with non-obstructive azoospermia.

Adult↗
PubMed1999

ADHD boys in young adulthood: psychosocial adjustment.

OBJECTIVE: To prospectively examine psychosocial functioning in young adulthood in children with attention-deficit/hyperactivity disorder (ADHD). METHOD: This 10-year prospective study compared psychosocial functioning in 18 young adult men in whom ADHD had been diagnosed in childhood and 18 male controls who had never been psychiatrically ill. Subjects' average age was 21 years at follow-up. Interviews assessed subjects' educational, occupational, residential, and marital status; utilization of mental health services; and psychological status. RESULTS: Young adults with ADHD were significantly more likely than controls to be using mental health services, to report psychological problems, and to have fathered children. In addition, a trend indicated that young men with ADHD were more likely to have dropped out of high school but subsequently attained a graduate equivalency diploma. There was also a trend for young adults with ADHD to report a greater history of trouble with the law; however, the groups did not differ on current legal problems. CONCLUSIONS: Overall, these young adults with ADHD appear to have overcome educational and legal difficulties experienced during high school. However, continued problems in psychological functioning appear to persist into young adulthood.

Adult↗
PubMed1999

The effects of finasteride on scalp skin and serum androgen levels in men with androgenetic alopecia.

BACKGROUND: Data suggest that androgenetic alopecia is a process dependent on dihydrotestosterone (DHT) and type 2 5alpha-reductase. Finasteride is a type 2 5alpha-reductase inhibitor that has been shown to slow further hair loss and improve hair growth in men with androgenetic alopecia. OBJECTIVE: We attempted to determine the effect of finasteride on scalp skin and serum androgens. METHODS: Men with androgenetic alopecia (N = 249) underwent scalp biopsies before and after receiving 0.01, 0.05, 0.2, 1, or 5 mg daily of finasteride or placebo for 42 days. RESULTS: Scalp skin DHT levels declined significantly by 13.0% with placebo and by 14.9%, 61.6%, 56. 5%, 64.1%, and 69.4% with 0.01, 0.05, 0.2, 1, and 5 mg doses of finasteride, respectively. Serum DHT levels declined significantly (P <.001) by 49.5%, 68.6%, 71.4%, and 72.2% in the 0.05, 0.2, 1, and 5 mg finasteride treatment groups, respectively. CONCLUSION: In this study, doses of finasteride as low as 0.2 mg per day maximally decreased both scalp skin and serum DHT levels. These data support the rationale used to conduct clinical trials in men with male pattern hair loss at doses of finasteride between 0.2 and 5 mg.

5-alpha Reductase Inhibitors↗
PubMed1999

Clinical dose ranging studies with finasteride, a type 2 5alpha-reductase inhibitor, in men with male pattern hair loss.

BACKGROUND: Androgenetic alopecia is a common condition of adult men. Finasteride, a type 2 5alpha-reductase inhibitor, decreases the formation of dihydrotestosterone from testosterone. OBJECTIVE: Two separate clinical studies were conducted to establish the optimal dose of finasteride in men with this condition. METHODS: Men from 18 to 36 years of age with moderate vertex male pattern hair loss received finasteride 5, 1, 0.2, or 0.01 mg/day or placebo based on random assignment. Efficacy was determined by scalp hair counts, patient self-assessment, investigator assessment, and assessment of clinical photographs. Safety was assessed by clinical and laboratory measurements and by analysis of adverse experiences. RESULTS: Efficacy was demonstrated for all end points for finasteride at doses of 0.2 mg/day or higher, with 1 and 5 mg demonstrating similar efficacy that was superior to lower doses. Efficacy of the 0.01 mg dose was similar to placebo. No significant safety issues were identified in the trials. CONCLUSION: Finasteride 1 mg/day is the optimal dose for the treatment of men with male pattern hair loss and was subsequently identified for further clinical development.

5-alpha Reductase Inhibitors↗
PubMed1998

History of atmospheric lead deposition since 12,370 (14)C yr BP from a peat bog, jura mountains, switzerland

A continuous record of atmospheric lead since 12,370 carbon-14 years before the present (14C yr BP) is preserved in a Swiss peat bog. Enhanced fluxes caused by climate changes reached their maxima 10, 590 (14)C yr BP (Younger Dryas) and 8230 (14)C yr BP. Soil erosion caused by forest clearing and agricultural tillage increased lead deposition after 5320 (14)C yr BP. Increasing lead/scandium and decreasing lead-206/lead-207 beginning 3000 (14)C yr BP indicate the beginning of lead pollution from mining and smelting, and anthropogenic sources have dominated lead emissions ever since. The greatest lead flux (15.7 milligrams per square meter per year in A.D. 1979) was 1570 times the natural, background value (0.01 milligram per square meter per year from 8030 to 5320 (14)C yr BP).

Journal Article↗
PubMed1998

Isolation and characterization of a heat-induced gene, hcit2, encoding a novel 16.5 kDa protein: expression coincides with heat-induced tolerance to chilling stress.

Heat treatment of tomato fruits induces tolerance to chilling injury. We have previously shown that specific heat-shock proteins (HSPs) are expressed in heated tomato fruits after cold storage. To search for heat-induced genes that are expressed at low temperatures, a cDNA library prepared from pre-heated chilled tomato fruits was differentially screened. A novel cDNA clone, hcit2, encoding a protein of ca. 16.5 kDa, was isolated. The predicted protein contains three putative trans-membrane hydrophobic sequences, suggesting that the protein is membrane-localized. The expression of hcit2 in fruits was induced by high temperature, but not by other stresses such as low temperature, drought or anaerobic conditions, and not during fruit ripening. A high level of hcit2 transcript was found in heated fruits after 2 weeks at 2 degrees C. High temperatures also induced hcit2 expression in tomato leaves, flowers and stems. The HCIT2 protein may be involved in the acquisition of tolerance to chilling injury.

Amino Acid Sequence↗
PubMed1998

Double trauma: a group therapy approach for Vietnam Veterans suffering from war and childhood trauma.

A model of a 9-month exploratory psychotherapy group for male Vietnam War veterans diagnosed with posttraumatic stress disorder (PTSD) who also experienced childhood physical and sexual abuse is presented. Recent literature delineating an association between combat PTSD and earlier childhood abuse is briefly reviewed and forms the basis for a new treatment strategy. A trauma group psychotherapy approach that investigates the connections between war and childhood traumas and their effects on later adult coping and interpersonal relationships is fundamentally different than existing trauma group treatment paradigms that focus primarily on war-related events. A description of the group formation, philosophy, course, and outcome is provided and enriched by clinical material.

Adaptation, Psychological↗
PubMed1998

Expression of small heat-shock proteins at low temperatures. A possible role in protecting against chilling injuries.

We previously reported that short exposure of tomato (Lycopersicon esculentum L.) fruits to high temperature protects them from chilling injury. To study the involvement of heat-shock proteins (HSPs) in the acquisition of low-temperature tolerance, we cloned two heat-shock-induced genes that are also expressed at low temperatures. The cloned cDNAs belong to the small HSP group. Sequence analyses of the clones showed perfect homology to the tomato-ripening gene tom66 and to the tomato chloroplastic HSP21 gene tom111. The expression of both genes was induced by high temperature in fruits, flowers, leaves, and stems, but not by low or ambient temperatures or by other stresses such as drought and anaerobic conditions. When the heated fruits were transferred to low temperature, tom66 and tom111 mRNA levels first decreased but were then reinduced. Induction was not observed in nonheated fruits at low temperature. Immunodetection of tom111-encoded protein indicated that this protein is present at low temperatures in the heated fruits. The results of this study show that the expression of tom66 and tom111 is correlated with protection against some, but not all, symptoms of chilling injury.

Acclimatization↗