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G Weiss

Publications and source records attributed to G Weiss.

At least 73 records · Page 4Linked to original sources

Intramucosal pH and liver endotoxin clearance during experimental liver transplantation.

The study was designed to assess the gastrointestinal ischaemia and the influence of the specific Kupffer cell toxin gadolinium chloride (GdCl3) on the hepatic and extrahepatic endotoxin [lipopolysaccharide (LPS)] clearance during experimental orthotopic liver transplantation (OLT) in pigs. In eight pig liver transplantations, the donors received 20 mg/kg of GdCl3 24 h before explantation, while controls (n = 8) received normal saline. Gastric and sigmoid intramucosal pH (pHi), LPS and endotoxin-neutralising capacity (ENC) levels were measured in the portal vein and superior vena cava after laparatomy, at the end of the anhepatic phase and 1 h after reperfusion. During the anhepatic phase, the sigmoid pHi decreased significantly from 7.32 +/- 0.02 to 7.29 +/- 0.03 (P < 0.001) and was associated with a substantial increase of portal LPS. Following reperfusion, the systemic LPS concentrations were significantly lower in the pretreated group [39 +/- 23 pg/ml (Control); 14 +/- 7 (GdCl3); P < 0.05] suggesting an improved liver LPS clearance [86% (GdCl3); 58.2% (Control); P < 0.05]. This corresponded to an increased ENC in the pretreated group [118 +/- 52 ENU/ml (GdCl3) vs 81 +/- 45 ENU/ml (Control); P < 0.05]. The anhepatic phase induced splanchnic ischaemia which correlated with portal endotoxaemia. Donor preconditioning with GdCl3 leads to lower systemic LPS concentrations in the recipient and increases ENC values in the early phase after OLT. An improved hepatocellular LPS extraction and/or an activation of the extrahepatic reticulo-endothelial system as a result of GdCl3 treatment is discussed.

Animals↗

Sequential (domino) transplantation of the liver in a transthyretin-50 familial amyloid polyneuropathy. Special reference to cardiological diagnosis and complications.

BACKGROUND: General shortage of cadaveric organs has led to a search for alternative methods to expand the donor pool. Sequential (domino) transplantation is yet another attempt to compensate for the declining consent to organ donation. PATIENTS AND METHODS: To qualify for a domino liver transplantation, the following preconditions must be fulfilled: (1) extrahepatic disease must exist, (2) liver must be fully functional, and (3) the genetic defect in the host should recur within a sufficient latency period. Familial amyloid polyneuropathy (FAP) is an autosomal dominant disease which involves a genetic defect for transthyretin (TTR), which is predominantly produced in the liver. RESULTS: In this report, we describe a rare case of a FAP TTR-50 variant undergoing domino liver transplantation. Since myocardial symptoms precede peripheral polyneuropathy, special emphasis should be placed on arrhythmias and the restrictive cardiomyopathy necessitating a veno-venous bypass or a cardiac pacemaker in order to improve cardiac contractility. The type of anastomosis of the suprahepatic inferior vena cava and possible alternatives are discussed. CONCLUSION: Despite ethical problems, the advantages of the domino procedure are obvious: (1) expansion of the donor pool, (2) ability to use living donors, and (3) presence of very short ischemic time and thus excellent liver function. Due to the kinetics of TTR production and deposition, donors and recipients of FAP livers should be followed up using an extensive neurological and cardiological protocol.

Adult↗

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↗

A phase II trial of topotecan in esophageal carcinoma: a Southwest Oncology Group study (SWOG 9339).

BACKGROUND: Chemotherapeutic treatments containing topoisomerase I inhibitors have shown antitumor activity against a number of solid tumors. Responses have been seen in Phase I trials using topotecan in ovarian, lung, and esophageal cancer. A phase II trial using continuous infusion topotecan was completed to assess activity in esophagus cancer. METHODS: Forty-five eligible patients with locally-advanced or metastatic squamous cell carcinoma or adenocarcinoma of the esophagus received a regimen consisting of 24-hour continuous infusion topotecan at 1.5 mg/m2/day on Days 1, 8, 15, 22 (of 42-day cycle). Patients continued on treatment until evidence of disease progression or unacceptable toxicity. RESULTS: Partial response was demonstrated in 1 patient (2% confirmed response rate). Thirty-six patients progressed during the first cycle of treatment. The median survival was 3 months, and the median progression-free survival was 1 month. Toxicity was mild with only one Grade 4 toxicity reported. CONCLUSIONS: This phase II trial indicates no significant anti-neoplastic activity for topotecan administered in the dose and schedule to patients with squamous cell or adenocarcinoma of the esophagus.

Adenocarcinoma↗

A phase I study of rhizoxin (NSC 332598) by 72-hour continuous intravenous infusion in patients with advanced solid tumors.

BACKGROUND: Rhizoxin (NSC 332598) is a novel macrolide antitumor antibiotic that inhibits microtubule assembly and also depolymerizes preformed microtubules. In preclinical evaluations, rhizoxin demonstrated broad antitumor activity in vitro and in vivo including both vincristine- and vindesine-resistant human lung cancers. Prolonged exposure schedules in xenograft models demonstrated optimal efficacy indicating schedule-dependent antitumor activity. The early phase I and II evaluations a five-minute bolus infusion schedule was studied, however, only modest anti-tumor activity was noted, possibly due to rapid systemic clearance. To overcome these limitations and to exploit the potential for schedule-dependent behavior of rhizoxin, the feasibility of administering rhizoxin as a 72-hour continuous intravenous (i.v.) infusion was evaluated. PATIENTS AND METHODS: Patients with advanced solid malignancies were entered into this phase I study, in which both the infusion duration and dose of rhizoxin were increased. The starting dose was 0.2 mg/m2 over 12 hours administered every 3 weeks. In each successive dose level, the dose and infusion duration were incrementally increased in a stepwise fashion. Once a 72-hour i.v. infusion duration was reached, rhizoxin dose-escalations alone continued until a maximum tolerated dose (MTD) was determined. RESULTS: Nineteen patients were entered into the study. Rhizoxin was administered at doses ranging from 0.2 mg/m2 i.v. over 12 hours to 2.4 mg/m2 i.v. over 72 hours every 3 weeks. The principal dose-limiting toxicities (DLT) were severe neutropenia and mucositis, and the incidence of DLT was unacceptably high at rhizoxin doses above 1.2 mg/m2, which was determined to be the MTD and dose recommended for phase II studies. At these dose levels, rhizoxin could not be detected in the plasma by a previously validated and sensitive high-performance liquid chromatography assay with a lower limit of detection of 1 ng/ml. No antitumor responses were observed. CONCLUSIONS: Rhizoxin can be safely administered using a 72-hour i.v. infusion schedule. The toxicity profile is similar to that observed previously using brief infusion schedules. Using this protracted i.v. infusion schedule the maximum tolerated dose is 1.2 mg/m2/72 hours.

Adult↗

Comparison of clinical outcomes following treatment of chronic adult periodontitis with subgingival scaling or subgingival scaling plus metronidazole gel.

BACKGROUND, AIMS: Conventional treatment of chronic periodontitis involves mechanical debridement of periodontal pockets. Recently, subgingival antimicrobials have been used adjunctively following such debridement. This 2-centre study compared the clinical effects of subgingival scaling (SRP) with SRP plus subgingival application of 25% metronidazole gel, Elyzol (SRP+gel), in patients with chronic adult periodontitis. METHOD: Voluntary informed written consent was obtained from 45 subjects at the Eastman (mean age 46, range 34-63) and 43 subjects at RAF Halton (mean age 47, range 34-71) who participated in this blind, randomised split-mouth design study. All had at least 2 sites in each quadrant with probing pocket depth (PPD) > or = 5 mm. PPD, bleeding on probing (BOP), and clinical probing attachment levels (CAL) measured using a stent, were recorded at baseline and at 1, 3, 6 and 9 months post-therapy. After subgingival scaling of all quadrants, 2 quadrants were randomly selected to be treated with metronidazole gel. RESULTS: A paired t-test on baseline values showed no bias between groups. Both treatments effectively reduced the signs of periodontitis. At each follow-up visit, reduction in PPD, CAL and BOP after the combined treatment was greater than for SRP alone. Paired t-tests showed that the improvement in the SRP+gel group was statistically significantly better (p<0.001) than for SRP alone (mean 0.5 +/- 0.6 mm. 95% CI 0.4-0.6 mm.) Similarly, the % of sites which improved to a final pocket depth of < or = 3 mm and the % of sites which improved over the 9 months of the study by as much as > or = 2 mm were greater for SRP+gel than for SRP alone. CONCLUSIONS: At the end of the study, the mean reductions for PPD were 1.0 mm (SRP) compared to 1.5 mm (SRP+gel), and for CAL they were 0.4 mm (SRP) compared to 0.8 mm (SRP+gel), with mean difference for CAL between treatments of 0.4 +/- 0.6 mm (95% confidence intervals of 0.3-0.6 mm). The combination therapy of SRP+gel was superior to the conventional treatment of SRP alone, and these differences were maintained for 9 months.

Adult↗

Relationship between TNF-alpha and iron metabolism in differentiating human monocytic THP-1 cells.

The human monocytic cell line THP-1 differentiates along the macrophage line after phorbol-12-myristate-13-acetate (PMA) supplementation and can be stimulated to secrete tumour necrosis factor alpha (TNF-alpha) by interferon gamma (IFN-gamma) addition. We found that, in the early stage of differentiation (1-48 h), PMA induction elicited an upregulation of intracellular H ferritin and H ferritin binding sites and a downregulation of transferrin receptor. In addition, we found that iron administration to PMA-differentiating cells induced the expression of TNF-alpha mRNA and TNF-alpha secretion to levels even higher than those induced by IFN-gamma alone. The iron chelator desferrioxamine showed the opposite effect and reduced TNF-alpha release. In contrast, preincubation of the cells with iron before PMA induction resulted in a decrease of the TNF-alpha secretion induced by IFN-gamma, whereas the opposite was true after preincubation with desferrioxamine. The data support a co-ordinate interaction between iron and TNF-alpha in monocyte macrophages, with an iron-mediated upregulation of TNF-alpha in the early phase of differentiation and an iron-mediated inhibition at later stages. This complex relationship has to be considered in evaluating the effects of iron on inflammation.

Binding Sites↗

Severe anaemia in Zambian children with Plasmodium falciparum malaria.

BACKGROUND: Severe anaemia and cerebral malaria are highly prevalent complications of Plasmodium falciparum malaria among African children. The mechanisms of severe malarial anaemia, and the relative importance of this condition in comparison to cerebral malaria, are not known for many regions of Africa. METHODS We reviewed the records of 6200 children up to 6 years of age admitted to one rural Zambian hospital between 1994 and 1996. Severe malarial anaemia was defined as an haemoglobin concentration < 5.0 g/dl in a patient with asexual forms of P. falciparum in the peripheral blood. Cerebral malaria was defined as impaired consciousness (Blantyre coma score < 5) not attributable to any other cause in a patient with a positive malaria smear. RESULTS Severe malarial anaemia was found in 590 children (9.5% of paediatric admissions) and strictly defined cerebral malaria occurred in 286 children (4.6% of paediatric admissions); 98 of these patients had the combination of both complications. Severe malarial anaemia correlated strongly with the degree of parasitaemia, with malnutrition as indicated by low weight for age, with absence of fever and with presentation late in the malaria season. In comparison, patients with cerebral malaria were more often febrile and presented earlier in the malaria season. The case fatality rate of severe malarial anaemia (0.088) was about half that of cerebral malaria (0.189), but because severe malarial anaemia was more common, these two forms of complicated malaria were implicated in similar numbers of in-hospital paediatric deaths. CONCLUSION Severe anaemia is a more common complication of P. falciparum malaria in hospitalized Zambian children than cerebral malaria and is associated with a similar number of deaths. Malnutrition and changes in immune response patterns due to prolonged exposure to P. falciparum may contribute to the development of this complication.

Anemia↗

Effect of granulocyte colony-stimulating factor treatment on ex vivo neutrophil functions in nonneutropenic surgical intensive care patients.

Granulocyte colony-stimulating factor (G-CSF) preferentially stimulates growth and differentiation of neutrophil precursors and activates neutrophil functions. The aim of the present study was to investigate the functional response of the neutrophil to exogenous recombinant human G-CSF (rHuG-CSF) in nonneutropenic patients. In 30 surgical intensive care unit patients with severely impaired wound healing, leukocyte differential count, plasma G-CSF level, and a broad spectrum of neutrophil functions were monitored before (day 0), throughout (days 1 and 5), and at days 1 and 5 after stopping G-CSF treatment. G-CSF application resulted in a 3.5-fold increase in peripheral blood granulocyte count at day 5 of treatment. The mean plasma G-CSF level rose from 48 to a maximum of 2314 pg/ml at day 1 of G-CSF therapy. Neutrophil chemotaxis and stimulated lysozyme release were decreased throughout G-CSF treatment, whereas respiratory burst activity, phagocytic activity, and intracellular calcium concentration were enhanced by G-CSF. Neutrophil membrane depolarization remained unaffected. The increased count and activation state of neutrophils were associated with clinical improvement in most of these patients. Thus, G-CSF may be a useful adjuvant treatment for nonneutropenic patients with severely impaired wound healing.

Adult↗

IFN-gamma and IL-4 differently regulate inducible NO synthase gene expression through IRF-1 modulation.

NO is a labile radical involved in several immunological, antimicrobial and inflammatory processes. In macrophages, NO formation is catalyzed by the cytokine-inducible enzyme inducible NO synthase (iNOS). The importance of IFN regulatory factor (IRF)-1 and of the signal transducers and activators of transcription (STAT)-1 for the induction of iNOS gene expression in response to IFN-gamma has been well defined. Here, we investigated the molecular events responsible for the inhibition of iNOS gene expression by IL-4 in the murine macrophage cell line RAW264.7. Unidirectional deletion analysis on iNOS promoter demonstrated that an IFN-stimulated responsive element (ISRE), contained in the -980 to -765 bp region of the iNOS promoter, may be involved in the IL-4-mediated inhibition of IFN-gamma-inducible iNOS transcription. Accordingly, the IFN-gamma-induced binding activity of IRF-1 to the ISRE sequence was reduced in cells pre-treated with IL-4, while the binding activity of STAT-1 to the STAT-binding element (SBE) within the same region of the iNOS promoter remained unaffected. Moreover, IL-4 even down-regulated IFN-gamma-inducible expression of IRF-1 mRNA. This could be related to a transcriptional mechanism by which IL-4 and IFN-gamma differentially influence the trans-acting activity of the STAT factors binding to SBE within the IRF-1 promoter. SBE is targeted by IFN-gamma-inducible STAT-1 and by IL-4-inducible STAT-6. Although STAT-6 has no trans-acting function on iNOS gene expression, it is able to inhibit the IFN-gamma-induced expression of IRF-1. Thus, IL-4 may down-regulate IFN-gamma-inducible iNOS transcription by activation of STAT-6 which in turn inhibits IRF-1 expression.

Animals↗

ADHD in parents.

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Adult↗

Phase I and pharmacologic study of PN401 and fluorouracil in patients with advanced solid malignancies.

PURPOSE: To assess the feasibility of administering PN401, an oral uridine prodrug, as a rescue agent for the toxic effects of fluorouracil (5-FU), and to determine the maximum-tolerated dose of 5-FU when given with PN401, with an 8-hour treatment interval between these agents. PATIENTS AND METHODS: Patients with advanced solid malignancies were treated with escalating doses of 5-FU, given as a rapid intravenous infusion weekly for 3 consecutive weeks every 4 weeks. PN401 was administered orally 8 hours after 5-FU administration, to achieve sustained plasma uridine concentrations of at least 50 micromol/L. Initially, patients received 6 g of PN401 orally every 8 hours for eight doses (schedule 1). When dose-limiting toxicity (DLT) was consistently noted, patients then received 6 g of PN401 every 2 hours for three doses and every 6 hours thereafter for 15 doses (schedule 2). RESULTS: Twenty-three patients received 50 courses of 5-FU and PN401. Among patients on schedule 1, DLT (grade 4 neutropenia complicated by fever and diarrhea) occurred in those receiving 5-FU 1,250 mg/m(2)/wk. Among patients on schedule 2, 5-FU 1,250 mg/m(2)/wk was well tolerated, but grade 4, protracted (> 5 days) neutropenia was consistently noted in those treated with higher doses of the drugs. Nonhematologic effects were uncommon and rarely severe. The pharmacokinetics of 5-FU, assessed in 12 patients on schedule 2, were nonlinear, with the mean area under the time-versus-concentration curve (AUC) increasing from 298 +/- 44 to 962 +/- 23 micromol/L and mean clearance decreasing from 34 +/- 4 to 15.6 +/- 0.38 L/h/m(2) as the dose of 5-FU was increased from 1,250 to 1,950 mg/m(2)/wk. 5-FU AUCs achieved with 5-FU 1,250 mg/m(2)/wk for 6 weeks along with the intensified PN401 dose schedule were approximately five-fold higher than those achieved with 5-FU alone. Plasma uridine concentrations increased with each of the three PN401 doses given every 2 hours, and uridine steady-state concentrations were greater than 50 micromol/L. CONCLUSION: Treatment with oral PN401 beginning 8 hours after 5-FU administration is well tolerated and results in sustained plasma uridine concentrations above therapeutic-relevant levels. The recommended 5-FU dosage for phase II evaluations is 1,250 mg/m(2)/wk for 3 weeks every 4 weeks with the intensified PN401 dose schedule (schedule 2). At this dose, systemic exposure to 5-FU as measured by AUC was five-fold higher than that observed after administration of a conventional 5-FU bolus.

Acetates↗

Luteal progesterone relates to histological endometrial maturation in fertile women.

To examine the relationship between endometrial histological maturation and reproductive hormones, we studied 11 fertile women, aged 18-37 yr. All participants had had at least 1 previous pregnancy and cycled regularly, every 25-35 days. Women collected daily, first morning voided urine for measurement of estradiol and progesterone metabolite excretion, estrone conjugates (E1c), and pregnanediol glucuronide (Pdg), respectively, throughout the cycle of study. Hormones were normalized for creatinine. Between 7-9 days after home detection of a LH surge (Sure Step), participants underwent an endometrial biopsy using a small bore (Pipelle) catheter. Tissue was prepared for histological and biochemical analyses. The histological analysis is reported herein. Endometrium was dated by 3 authors (N.S., D.H., and S.P.), all of whom were blinded to the participant's identity or timing of biopsy within her cycle. Final dating was agreed upon based upon the method of Noyes et al. E1c and Pdg were integrated throughout the cycle using the trapezoidal rule, and correlations were sought between deviation from expected histology (based upon urinary hormones and LH surge) and integrated hormone values. E1c varied over a 2-fold range in these normal women, from 1196-2040 ng/cycle. Pdg excretion was much more variable, ranging from 22-119 microg/cycle. No relationship could be found between histological lagging of endometrial maturation and lower excretion of E1c. A moderate correlation was observed (Spearman's r = 0.6; P < 0.05) between degree of histological maturation and integrated Pdg. Of two women with evidence of a disparity between gland and stromal development (glands lagging behind stroma by >2 days), one excreted 24 microg Pdg/cycle, the next to lowest value. We conclude that normal fertile women experience a wide range of hormone concentrations in the face of normal endometrial maturation. Progesterone appears to exert a dose-related effect on endometrial maturation, and the techniques we used, although relatively crude clinical measures, appeared to be sufficient to detect this relationship.

Adolescent↗

Markers of inflammation in children with severe malarial anaemia.

OBJECTIVE: To investigate if severe malarial anaemia is associated with a specific immune response pattern, we determined serum levels of neopterin (a marker of activation of macrophages by interferon-gamma) and of the anti-inflammatory cytokines, interleukins 4 and 10. METHODS: Zambian children < 6 years of age presenting to a rural hospital with cerebral malaria were studied. Twenty-one children with admission haemoglobin concentrations </= 5 g/dl were classified as having severe anaemia and 40 with haemoglobin concentrations >/= 7 g/dl served as a control group. RESULTS: Logistic regression modelling indicated that a 10-fold rise in serum neopterin concentrations was associated with a 50-fold increase in the estimated odds of having severe anaemia (P = 0.015), while a 10-fold rise in serum interleukin 4 concentrations was associated with a 10-fold decrease in the estimated odds of having severe anaemia (P = 0.023). Increasing serum interleukin 10 concentrations, measured in less than half of the subjects, were associated with a nonsignificant reduction in the odds of having severe anaemia (P = 0.095). CONCLUSION: Development of severe malarial anaemia may be directly associated with serum neopterin concentrations and inversely correlated with serum interleukin 4 levels.

Anemia↗