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Biomedical subjects

J Weiss

Publications and source records attributed to J Weiss.

At least 73 records · Page 4Linked to original sources
PubMed2000

Effect of diazepam on the immune response of rats exposed to acute and chronic swim stress.

To examine the effect of the anti-stress agent diazepam on the immune response, rats were exposed either to acute swim stress, i.e., swimming once only for 30 minutes (non-trained swimmers), or to chronic stress with gradual progressive training for 6 weeks (trained swimmers). Both groups of animals were divided into subgroups treated before swimming with and without diazepam, 1 mg/kg, administered i.m. The phagocytic capacity and superoxide anion generation of the peritoneal macrophages was examined. In addition, the proliferative response of the splenic cells (splenocytes) to concanavalin A (Con A) and phytohemagglutinin (PHA), as well as the serum corticosterone levels were investigated. Diazepam abolished increased superoxide anion production in both non-trained and trained swimmers. In non-trained swimmers, the number of latex particles internalized by each cell was decreased and further reduced by the drug. In trained rats treated with diazepam, the percentage of phagocytosing cells remained reduced compared to controls, whereas the drug prevented a decrease in the engulfing capacity of individual cells. Diazepam lowered the suppressed proliferative response of the splenocytes to PHA found in non-trained swimmers. It is concluded that diazepam modifies the immune response of rats exposed to acute and chronic swim stress.

Animals↗
PubMed2000

Addition of sugars influences color of oil-in-water emulsions.

The influence of glucose, fructose, lactose, and glycerol on the color and appearance of surfactant-stabilized oil-in-water emulsions containing a red dye was investigated. A stabilized (Tween-20) oil-in-water emulsion was diluted into sugar solutions to give a range of oil droplet and sugar concentrations. Tristimulus coordinates (L, a, b) and reflectance spectra were measured using a spectrophotometer. With increasing sugar concentration, reflectance spectra shifted to lower reflectance values. Tristimulus coordinates were reduced by approximately 50% for emulsions containing high concentrations of sugar. Adding fructose to emulsions reduced L, a, b values more significantly than adding glucose, lactose, or glycerol. Tristimulus coordinates remained constant when the temperature was raised from 20 to 80 degrees C. The experimental results were explained in terms of the change of relative refractive index at the water-oil interface. The results have important implications for the food industry as they offer a new means to control and optimize the color of food emulsions.

Carbohydrates↗
PubMed2000

Effects of stimulant medication treatment on mothers' and children's attributions for the behavior of children with attention deficit hyperactivity disorder.

Participants were 55 children with attention deficit hyperactivity disorder (ADHD) who were receiving ongoing treatment with stimulant medications and their mothers, and 31 children with ADHD who were beginning stimulant medication and their mothers. Mothers and children offered attributions for child behaviors that occurred when the child was medicated and not medicated. Mothers rated child compliance and prosocial behavior as more global and stable when the child was medicated and rated noncompliance, ADHD symptoms, and oppositional behavior as more externally caused, less global and stable, but more controllable by the child when the child was medicated. Children rated both their compliance and noncompliance as more controllable in the medicated condition. On a forced-choice measure, both mothers and children selected ability, effort, and task attributions for compliance more in the not-medicated condition, and pill-taking attributions more in the medicated condition. This was reversed for noncompliance, which was attributed more to effort, task, or ability in the medicated condition and more to not taking a pill in the not-medicated condition. The potential risks and benefits for parent-child interactions and children's self-perceptions of these medication-related differences in attributions are discussed.

Adolescent↗
PubMed2000

Abdominal recovery after laparotomy and omental transposition into a grossly contaminated median sternotomy wound.

Grossly contaminated median sternotomy wounds are frequently treated with transposed omental flaps. A laparotomy adjacent to such an infected wound carries the risk of peritonitis. It has been suggested that this risk may increase when the omentum, which has anti-infective properties, is removed from the abdominal cavity and is transposed to the chest. The authors evaluated abdominal recovery after laparotomy and omental transposition into an adjacent, grossly contaminated median sternotomy wound. The study group included 15 patients who had sternal wound reconstruction with an omental flap between 1990 and 1998. All patients underwent median sternotomy reconstruction according to a "two-compartment" operative sequence protocol, which included division of the surgical field into an upper (thoracic) contaminated zone and a lower (abdominal) clean zone. The control group was comprised of 15 patients who underwent elective laparotomy for splenectomy during the same time period. The effect of the surgical procedure on the abdomen was compared between the two groups. The timing of the reappearance of peristalsis and regular bowel function, and the incidence of bowel obstruction and postoperative peritonitis were similar in the two groups. The findings indicate that laparotomy and omental transposition in the presence of a grossly contaminated median sternotomy wound is a safe procedure, and is associated with a low rate of abdominal complications.

Aged↗
PubMed2000

Quantitative estimation of attenuation in ultrasound video images: correlation with histology in diffuse liver disease.

RATIONALE AND OBJECTIVES: To determine the relationship between the attenuation of backscatter intensity in B-scan images of the liver and diffuse liver disease in order to assess the usefulness of this method in providing quantitative objective characterization of diffuse liver diseases in general and in fatty liver in particular. METHODS: Twenty-four healthy volunteers and 28 patients with elevated liver enzyme levels who underwent liver biopsy were included in this study. An automatic far-field slope (FFS) algorithm that estimates the decrease in amplitude of the backscattered echo as a function of beam depth was implemented on the noncompensated image that was acquired on a commercial phased-array ultrasound system fitted to a custom-built interface card. The images were processed at a work-station. All scans were acquired repeatedly, read, and graded blindly by experienced ultrasound radiologists. Histology obtained via needle biopsy was reviewed without knowledge of the ultrasound findings. RESULTS: Analysis of the FFS data for fatty infiltration in all patient groups yielded a sensitivity of 67%, a specificity of 77%, a positive predictive value (PPV) of 77%, negative predictive value (NPV) of 67%, and an accuracy of 71%. The mean score of the ultrasound reviewers showed a sensitivity of 82%, a specificity of 66%, a PPV% of 68%, an NPV of 81%, and an accuracy of 72%. Normal FFS values (false-negative) were found in five patients with proved fatty infiltration. All of these patients had coexistent moderate to severe hepatic inflammation. However, FFS data in patients with uncomplicated (pure) fatty infiltration revealed a sensitivity of 100%, a specificity of 80%, a PPV of 89%, an NPV of 100%, and an accuracy of 92%. The best ultrasound score yielded a sensitivity of 100%, a specificity of 60%, a PPV of 80%, an NPV of 100%, and an accuracy of 85% in the same patients. CONCLUSIONS: The data demonstrate an excellent sensitivity (100%) of the FFS values in patients with uncomplicated fatty infiltration. This was also the only group of patients in whom the FFS score was superior to the radiologists' best score. The FFS method can be used as a tool to follow up the response to a clinical or research treatment and to obtain standardization of pattern interpretation independently of the individual reader.

Adolescent↗
PubMed2000

Phospholipid synthesis by Staphylococcus aureus during (Sub)Lethal attack by mammalian 14-kilodalton group IIA phospholipase A2.

Killing of gram-positive bacteria by mammalian group IIA phospholipases A2 (PLA2) requires the catalytic activity of the enzyme. However, nearly complete degradation of the phospholipids can occur with little effect on bacterial viability, suggesting that PLA2-treated bacteria can biosynthetically replace phospholipids that are lost due to PLA2 action. In the presence of albumin, phospholipid degradation products are quantitatively sequestered extracellularly. In the absence of albumin, the bacteria retain and substantially reutilize the phospholipid breakdown products and survive an otherwise lethal dose of PLA2. PLA2-treated bacteria also continue to incorporate sodium [2-(14)C]acetate into phospholipids, suggesting that the bacteria are attempting to repair the damaged membranes by de novo synthesis of phospholipids. To determine whether PLA2 action also triggers activation of bacterial lipolytic enzymes, the effects of nisin and PLA2 on the degradation of S. aureus lipids were compared. In contrast to nisin treatment, PLA2 treatment does not stimulate endogenous phospholipase activity in S. aureus. These findings show that S. aureus responds to PLA2 attack by continued phospholipid (re)synthesis by both de novo and salvage pathways. The fate of PLA2-treated S. aureus therefore appears to depend on the relative rates of phospholipid degradation and synthesis.

Acetates↗
PubMed2000

Warnings about vulnerability in clients with diabetes and hypertension.

The purpose of the grounded theory study discussed in this article was to discover and explicate the basic social problem in clients with diabetes and hypertension that affects their adherence to health care directives. In-depth interviews with 21 clients with both diabetes and hypertension and 3 health care providers who care for such clients were concurrently conducted, coded, and analyzed according to the grounded theory method. Clients with diabetes and hypertension described being bombarded repeatedly with warnings about their vulnerability. The warnings were both external (coming from health care providers, family, and friends) and internal (coming from within themselves). Internal warnings were discovered to be far more influential in affecting adherence. This discovery can be used to shape health care providers' social interactions and treatment plan strategies with clients with diabetes and hypertension.

Attitude to Health↗
PubMed2000

Randomized phase III study of temozolomide versus dacarbazine in the treatment of patients with advanced metastatic malignant melanoma.

PURPOSE: To compare, in 305 patients with advanced metastatic melanoma, temozolomide and dacarbazine (DTIC) in terms of overall survival, progression-free survival (PFS), objective response, and safety, and to assess health-related quality of life (QOL) and pharmacokinetics of both drugs and their metabolite, 5-(3-methyltriazen-1-yl)imidazole-4-carboximide (MTIC). PATIENTS AND METHODS: Patients were randomized to receive either oral temozolomide at a starting dosage of 200 mg/m(2)/d for 5 days every 28 days or intravenous (IV) DTIC at a starting dosage of 250 mg/m(2)/d for 5 days every 21 days. RESULTS: In the intent-to-treat population, median survival time was 7.7 months for patients treated with temozolomide and 6.4 months for those treated with DTIC (hazards ratio, 1.18; 95% confidence interval [CI], 0.92 to 1.52). Median PFS time was significantly longer in the temozolomide-treated group (1.9 months) than in the DTIC-treated group (1.5 months) (P =.012; hazards ratio, 1.37; 95% CI, 1.07 to 1.75). No major difference in drug safety was observed. Temozolomide was well tolerated and produced a noncumulative, transient myelosuppression late in the 28-day cycle. The most common nonhematologic toxicities were mild to moderate nausea and vomiting, which were easily managed. Temozolomide therapy improved health-related QOL; more patients showed improvement or maintenance of physical functioning at week 12. Systemic exposure (area under the curve) to the parent drug and the active metabolite, MTIC, was higher after treatment with oral temozolomide than after IV administration of DTIC. CONCLUSION: Temozolomide demonstrates efficacy equal to that of DTIC and is an oral alternative for patients with advanced metastatic melanoma.

Adult↗
PubMed2000

Survivor guilt, submissive behaviour and evolutionary theory: the down-side of winning in social comparison.

In prior research submissive behaviour has been studied in relation to social comparison. Evolutionary theory conceptualized submissive behaviour as a fear-based self-protective strategy when in a subordinate position. In this study we hypothesized that survivor guilt, the type of guilt associated with feeling better off than others, is also linked to submissive behaviour. The Interpersonal Guilt Questionnaire, the Submissive Behaviour Inventory, the Eysenck Personality Questionnaire-Revised and the Automatic Thoughts Questionnaire were administered to a sample of 199 college students. Submissive behaviour was found to be significantly correlated with survivor guilt. Introversion, used as an indirect measure of the fear of being put down, was also correlated with submissive behaviour. A principal components analysis found two components: the first was composed of high loadings of submissiveness, survivor guilt and omnipotent responsibility guilt; the second was composed of high loadings of submissiveness and introversion. This supports the hypothesis that there may be two motivational states related to submissive behaviour, the fear of harm to the self, as described in prior studies, and the fear of harm to another or guilt-based submissive behaviour. We propose that survivor guilt has been selected by evolution as a psychological mechanism supporting group living, and that it may be considered from the perspective of inclusive fitness, reciprocal altruism, and multilevel selection theory.

Adaptation, Psychological↗
PubMed2000

11q23 allelic loss is associated with regional lymph node metastasis in melanoma.

Genetic alterations of the long arm of chromosome 11 have been implicated in melanoma pathogenesis, and we recently identified two distinct regions of common allelic loss in chromosomal band 11q23. To establish the point in time of melanoma tumorigenesis at which these two putative tumor suppressor loci become relevant, we investigated allelic loss [loss of heterozygosity (LOH)] in both chromosomal regions in tumors of progressing patients. We analyzed 102 tumor samples from 23 patients for whom at least two (10 patients) or three (13 patients) tumor samples from different clinical progression steps (such as primary tumor and/or in-transit metastasis and/or regional lymph node metastasis and/or distant metastasis) were available. We detected no 11q23 LOH at any stage in 3 of 23 patients and detected LOH at all stages tested in 8 of 23 patients. In 8 of the remaining 12 (67%) patients with 11q23 LOH at some stage during tumor progression, we found this to occur first at regional lymph node metastasis. Two of these patients retained constitutional heterozygosity in several in-transit metastases that developed up to 7 months after lymph node metastases that already had loss. We therefore conclude that 11q23 LOH is associated with regional lymph node metastasis in melanoma. Finally, we detected an allele shift restricted to a histomorphologically distinct part of a primary melanoma and found that the same parental chromosome was affected by allelic loss in a subsequently occurring lymph node metastasis. These findings support our conclusion and give additional evidence for the hypothesis of molecular heterogeneity of early tumor cell populations in melanoma.

Alleles↗
PubMed1999

Deacylation of lipopolysaccharide in whole Escherichia coli during destruction by cellular and extracellular components of a rabbit peritoneal inflammatory exudate.

Deacylation of purified lipopolysaccharides (LPS) markedly reduces its toxicity toward mammals. However, the biological significance of LPS deacylation during infection of the mammalian host is uncertain, particularly because the ability of acyloxyacyl hydrolase, the leukocyte enzyme that deacylates purified LPS, to attack LPS residing in the bacterial cell envelope has not been established. We recently showed that the cellular and extracellular components of a rabbit sterile inflammatory exudate are capable of extensive and selective removal of secondary acyl chains from purified LPS. We now report that LPS as a constituent of the bacterial envelope is also subject to deacylation in the same inflammatory setting. Using Escherichia coli LCD25, a strain that exclusively incorporates radiolabeled acetate into fatty acids, we quantitated LPS deacylation as the loss of radiolabeled secondary (laurate and myristate) and primary fatty acids (3-hydroxymyristate) from the LPS backbone. Isolated mononuclear cells and neutrophils removed 50% and 20-30%, respectively, of the secondary acyl chains of the LPS of ingested whole bacteria. When bacteria were killed extracellularly during incubation with ascitic fluid, no LPS deacylation occurred. In this setting, the addition of neutrophils had no effect, but addition of mononuclear cells resulted in removal of >40% of the secondary acyl chains by 20 h. Deacylation of LPS was always restricted to the secondary acyl chains. Thus, in an inflammatory exudate, primarily in mononuclear phagocytes, the LPS in whole bacteria undergoes substantial and selective acyloxyacyl hydrolase-like deacylation, both after phagocytosis of intact bacteria and after uptake of LPS shed from extracellularly killed bacteria. This study demonstrates for the first time that the destruction of Gram-negative bacteria by a mammalian host is not restricted to degradation of phospholipids, protein, and RNA, but also includes extensive deacylation of the envelope LPS.

Acylation↗
PubMed1999

Decreased phagocytic capacity of rat peritoneal macrophages following photon abdominal irradiation.

Photon irradiation of the abdomen may be accompanied by complications due to a decrease in the immune defense of the recipient. Since peritoneal macrophages are an important component of the immune system, we examined the phagocytic activity and oxygen superoxide anion generation by peritoneal macrophages from rats 2 and 4 weeks after abdominal irradiation with 6 MV photons applying a single dose of 2 Gy. Two and 4 weeks after irradiation, peritoneal macrophages were harvested and their capacity to engulf latex particles and to produce oxygen superoxide anions was determined. Non-irradiated rats, treated identically otherwise, served as controls. Two weeks after irradiation the phagocytic capacity and oxygen superoxide anion generation decreased by 61 and 70%, respectively, compared with controls. This tendency persisted after 4 weeks post irradiation, the decrease in both functions being 50 and 74%, respectively. It is suggested that the altered function of peritoneal macrophages following irradiation may further compromise the immune defense in patients receiving abdominal radiotherapy.

Abdomen↗