Search PubMed⌕ Search

Biomedical subjects

J Werner

Publications and source records attributed to J Werner.

At least 55 records · Page 3Linked to original sources
PubMed2001

Desmopressin impairs microcirculation in donor pancreas and early graft function after experimental pancreas transplantation.

BACKGROUND: Protective effects of desmopressin in brain dead organ donors oppose reports on a hypercoagulatory potential and an increased leukocyte-endothelial interaction (LEI) after application of the drug. The aim was to evaluate the effect of desmopressin on organ donor's pancreas and early graft function. METHODS: Donor microcirculation was evaluated via intra-vital microscopy (IVM) in 24 BR (di/di) rats with central diabetes insipidus, randomly assigned to groups I (control without desmopressin application), II (single i.v. application, no pretreatment) or group III (single i.v. desmopressin application, s.c. pretreatment for 3 days). Microcirculation in recipients was evaluated 1 hr and 6 hr after syngenic pancreas transplantation. Groups III and I served as organ donors. After IVM specimens were taken for histology and immunohistochemistry. RESULTS: Desmopressin in II vs. I led to temporarily (30') increased LEI (Sticker 274.3+/-87.7 vs. 76.5+/-31.1/mm2 endothelial surface; P<0.01) and impaired microcirculation (MCEV 0.43+/-0.07 vs. 0.99+/-0.06 mm/s; P<0.01). Repeated application reduced MCEV and increased LEI for up to 12 hr. Histology in I vs. III showed increased inflammation (n.s.), necrosis (P<0.05) and vacuolization (P<0.01). Immunohistochemistry revealed increased endothelial P-selectin 20' after application. 6 hr after reperfusion organs from III showed reduced MCEV and increased LEI (P<0.01). CONCLUSION: Repeated application of desmopressin impairs graft microcirculation. Perfusion of the pancreas is significantly reduced at the beginning of organ tissue conservation as well as after reperfusion. These disturbances might partly be due to observed endothelial P-selectin expression. Application of desmopressin up to 12 hr prior to organ explantation may impact graft quality.

Animals↗
PubMed2001

Phase II study of the cyclin-dependent kinase inhibitor flavopiridol administered to patients with advanced gastric carcinoma.

PURPOSE: Flavopiridol is the first cyclin-dependent kinase inhibitor to enter clinical trials. Activity in gastric cancer xenografts and in a patient with gastric cancer on the phase I trial led to this phase II study of flavopiridol in patients with metastatic gastric cancer. PATIENTS AND METHODS: Sixteen patients were entered onto the study, and 14 were assessable for response. Flavopiridol was administered initially at a dose of 50 mg/m(2)/d by continuous infusion for 72 hours every 2 weeks. Assessment of plasma pharmacokinetics was performed in all patients. Peripheral mononuclear cells were collected throughout the 72-hour infusion for determinants of apoptosis. RESULTS: There were no major objective responses (exact confidence interval 0% to 23%). One patient achieved a minor response in his liver metastases, though the primary progressed. Other patients exhibited histologic and radiographic evidence of tumor necrosis. Common toxicities included fatigue in 93% of patients (grade 3 or 4 in 27%) and diarrhea in 73% of patients (grade 3 or 4 in 20%). Five patients (33%) developed venous thromboses at the central catheter tip. The studies performed on peripheral mononuclear cells indicated no induction of apoptosis. CONCLUSION: Flavopiridol administered as a single agent for 72 hours every 14 days is inactive in the treatment of gastric cancer. The drug also induced an unexpected higher incidence of vascular thrombosis and fatigue than was anticipated from the phase I trials. Future development of flavopiridol will depend on other doses and schedules in combination with chemotherapy.

Adenocarcinoma↗
PubMed2001

[Importance of intraoperative parathormone measurements in primary hyperparathyroidism with 5-gland hyperplasia].

While intraoperative parathormone measurements are mandatory for unilateral operations of primary hyperparathyroidism (pHPT), its value for treatment of parathyroid hyperplasia is regarded as insufficient. We report a case of a pHPT with hyperplasia of five glands, in which only the intraoperative analysis of parathormone detected the remaining fifth hyperparathyroid gland after extirpation of four enlarged parathyroid glands. We describe technical problems involved in the tests available today and how the results of the intraoperative parathormone test need to be interpreted. As several factors can influence the decrease in parathormone concentration, a kinetic analysis may be more accurate in assessing the adequacy of resection. Therefore, intraoperative parathormone measurements are especially useful and important for adequate surgical therapy for pHPT with parathyroid hyperplasia.

Adult↗
PubMed2001

Mediator, not holoenzyme, is directly recruited to the heat shock promoter by HSF upon heat shock.

Activators of RNA polymerase II (Pol II) transcription have been shown to bind several coactivators and basal factors in vitro. Whether such interactions play a primary regulatory role in recruiting these factors to activator-associated chromosomal target sites in living cells remains unclear. Here, we show that upon heat shock the Pol II-free form of Mediator is rapidly recruited to HSF binding sites. Unlike the TAFs and Pol II, the interaction between Mediator and HSF on chromosomal loci is direct and mechanistically separable from the preinitiation complex assembly step. Therefore, the activator-Mediator interaction likely underlies the initiation of signal transfer from enhancer-bound activators to the basal transcription machinery.

Amanitins↗
PubMed2001

Biological implications of tumor cells in blood and bone marrow of pancreatic cancer patients.

BACKGROUND: Patients with pancreatic cancer often have tumor recurrence despite curative resection. Cancer cells detected in blood or bone marrow at the time of diagnosis may relate to tumor stage and to prognosis. Recent research emphasis has centered on tumor cells in bone marrow aspirates, but whether these represent early micrometastases or blood-borne cells in transit is unknown. PATIENTS AND METHODS: We developed a specific immunocytochemical assay that evaluated more than 5.3 x 10(6) extracted mononuclear cells per sample of blood and bone marrow and that could identify a single tumor cell in that population. The assay was applied to samples of blood and bone marrow from 105 patients with pancreatic cancer and 66 controls. The prevalence of isolated tumor cells was compared with Union Internationale Contre le Cancer (UICC) stage. A multivariate Cox regression analysis for survival was performed. RESULTS: Pancreatic cancer cells were detected in 26% of blood samples and in 24% of bone marrow specimens. Specificity for cancer was 96%. The prevalence of isolated tumor cells in patients with proven resectable cancer was 9% in blood and 13% in bone marrow. The prevalence increased with UICC tumor stage in blood (P =.04) but not in bone marrow (P =.52) and correlated in blood with resectability (P =.02), progression of disease (P=.08), and peritoneal dissemination (P =.003). While survival correlated significantly with tumor stage (P <.001) and isolated tumor cells in blood correlated with tumor stage, the finding of cancer cells in blood or bone marrow, or both, was not independently associated with survival in patients with pancreatic cancer. CONCLUSIONS: Isolated tumor cells in blood but not bone marrow reflect the stage of growth and spread of pancreatic cancer, particularly in the peritoneal cavity. The findings are consistent with cells in bone marrow aspirates being in transit, not implanted. These disseminated cancer cells may be the consequence, rather than the cause, of progression.

Aged↗
PubMed2001

Linkage of oxidative and nonoxidative ethanol metabolism in the pancreas and toxicity of nonoxidative ethanol metabolites for pancreatic acinar cells.

BACKGROUND: Alcohol abuse is a major cause of pancreatic damage. Recent experimental evidence suggests that fatty acid ethyl esters (FAEE), nonoxidative ethanol metabolites, injure pancreatic acinar cells. Linkage between oxidative and nonoxidative metabolism of ethanol in the pancreas may contribute to increased FAEE levels. METHODS: To study the association between oxidative and nonoxidative ethanol metabolism, FAEE concentration and FAEE synthase activity in rat pancreatic and liver homogenates incubated with ethanol were evaluated with and without inhibitors of oxidative ethanol metabolism. For toxicity studies, trypsinogen activation peptide synthesis as a measure of pancreatic cell injury was quantitated in unstimulated and cerulein-stimulated isolated pancreatic acinar cells incubated with ethanol or FAEE. RESULTS: Inhibition of oxidative ethanol metabolism results in a 2- to 3-fold increase in nonoxidative ethanol metabolism to FAEE in pancreas and in liver. Both ethanol and FAEE induce increased intracellular trypsinogen activation by more than 50% in the presence of physiologic concentrations of cerulein in vitro. CONCLUSIONS: These findings demonstrate that the inhibition of oxidative ethanol metabolism results in an increase in flux through the nonoxidative pathway and support the proposition that alcohol-induced pancreatic injury is mediated at least in part by FAEE, which are important products of pancreatic ethanol metabolism.

Acyltransferases↗
PubMed2001

Cariporide (HOE 642) attenuates leukocyte activation in ischemia and reperfusion.

UNLABELLED: Cariporide (HOE 642) ameliorates myocardial ischemia/reperfusion (I/R) injury, by the well established reduction of cytosolic [Ca(2+)] in cardiac myocytes through inhibition of Na(+)/H(+) exchange. However, postischemic inflammation also contributes to I/R injury. We tested the hypothesis that cariporide also modulates the inflammatory response. The effect of cariporide on L-selectin expression by human leukocytes in vitro and leukocyte adhesion and emigration in the reperfused rat cremaster muscle in vivo were studied. The rat cremaster muscle was exteriorized for intravital videomicroscopy, induction of ischemia (90 min), and reperfusion (90 min). Eleven rats were pretreated with cariporide (9 mg/kg body weight IV) whereas 11 rats received saline. Leukocyte adhesion was quantified offline. Human venous blood was incubated with cariporide (3 micromol/L) or saline, stimulated with formyl- methionine-leucine-phenylalanine (10(-10)-10(-6) mol/L), and granulocyte L-selectin expression was analyzed by flow cytometry. Cariporide reduced leukocyte rolling and adhesion by approximately 35% and 45%, respectively, after 30 min of reperfusion. Leukocyte extravasation was decreased by approximately 85% after 90 min. Cariporide increased L-selectin shedding at each formyl-methionine-leucine-phenylalanine concentration, reducing the 50% effective dose from 9.95 to 4.68 nmol/L. Thus, cariporide may ameliorate I/R injury not only by the known reduction of cytosolic [Ca(2+)] in cardiomyocytes, but also by attenuating leukocyte-dependent inflammatory responses. Promotion of L-selectin shedding from activated leukocytes may present a mechanism underlying this newly detected effect. IMPLICATIONS: This study provides evidence that inhibition of Na(+)/H(+) exchange by cariporide (HOE 642) attenuates the postischemic inflammatory response. Leukocyte adhesion and emigration, assessed by in vivo microscopy, were markedly reduced in rat cremaster muscle, possibly because of increased L-selectin shedding of activated leukocytes as demonstrated by flow cytometry.

Animals↗
PubMed2001

Promoting effect of a high-fat/high-protein diet in DMBA-induced ductal pancreatic cancer in rats.

OBJECTIVE: To investigate whether a high-fat/high-protein diet (HFPD) acts as a promoter of the natural course of cancer growth in the 7,12-dimethylbenzanthracene (DMBA)-induced ductal pancreatic cancer model in rats. SUMMARY BACKGROUND DATA: DMBA implantation to the rat pancreas induces ductal adenocarcinoma. Information regarding the effects of diet and the presence of K-ras mutation in this model is not available. METHODS: Rats were randomly assigned to regular rat chow or a diet with a 30% content in fat and protein (HFPD). The presentation of cancer, the histologic spectrum of neoplasia at 1 and 9 months, and the prevalence of cancer in relation to diet were assessed. Histologic specimens comprising normal ducts, hyperplasia, dysplasia/carcinoma in situ, or carcinoma were designated by a pathologist and microdissected. Genomic DNA was extracted, and K-ras and H-ras gene mutations were determined by a mutant-enriched polymerase chain reaction assay and direct sequencing. RESULTS: Rats fed HFPD increased their weight significantly compared with controls. DMBA induced characteristic stages of neoplasia at the implant site but not elsewhere. Macroscopic cancers of the pancreatic head presented regularly with common bile duct and gastric outlet obstruction. The prevalence of K-ras mutations was proportional to the degree of epithelial abnormality. K-ras mutations were significantly more frequent in cancer than in normal and hyperplastic ducts. H-ras mutations were not found. At 1 month in the HFPD-fed rats, the prevalence of cancer (16%) and dysplasia (16%) was not significantly different from the prevalence of cancer (29%) and dysplasia (8%) in the chow-fed rats. At 9 months the prevalence of cancer in the HFPD-fed rats increased to 29%, whereas that in the chow-fed rats decreased to 17%. The combined prevalence of cancer and dysplasia at 9 months in the HFPD-fed rats (34%) significantly exceeded that in the chow-fed rats. CONCLUSIONS: DMBA induces characteristic stages of neoplasia in the evolution of ductal pancreatic cancer in rats. K-ras mutations occur progressively in the ladder of oncogenesis, as in human pancreatic neoplasms. The addition of a diet with a high fat and protein content acts as a promoter of carcinogenesis, possibly by interfering with repair mechanisms and natural regression of early lesions.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2001

Improving depression outcomes in community primary care practice: a randomized trial of the quEST intervention. Quality Enhancement by Strategic Teaming.

OBJECTIVE: To determine whether redefining primary care team roles would improve outcomes for patients beginning a new treatment episode for major depression. DESIGN: Following stratification, 6 of 12 practices were randomly assigned to the intervention condition. Intervention effectiveness was evaluated by patient reports of 6-month change in 100-point depression symptom and functional status scales. SETTING: Twelve community primary care practices across the country employing no onsite mental health professional. PATIENTS: Using two-stage screening, practices enrolled 479 depressed adult patients (73.4% of those eligible); 90.2% completed six-month follow-up. INTERVENTION: Two primary care physicians, one nurse, and one administrative staff member in each intervention practice received brief training to improve the detection and management of major depression. MAIN RESULTS: In patients beginning a new treatment episode, the intervention improved depression symptoms by 8.2 points (95% confidence interval [CI], 0.2 to 16.1; P =.04). Within this group, the intervention improved depression symptoms by 16.2 points (95% CI, 4.5 to 27.9; P =.007), physical role functioning by 14.1 points (95% CI, 1.1 to 29.2; P =.07), and satisfaction with care (P =.02) for patients who reported antidepressant medication was an acceptable treatment at baseline. Patients already in treatment at enrollment did not benefit from the intervention. CONCLUSIONS: In practices without onsite mental health professionals, brief interventions training primary care teams to assume redefined roles can significantly improve depression outcomes in patients beginning a new treatment episode. Such interventions should target patients who report that antidepressant medication is an acceptable treatment for their condition. More research is needed to determine how primary care teams can best sustain these redefined roles over time.

Adult↗
PubMed2001

Altered distribution of lipid-soluble antioxidant vitamins in juvenile sturgeon exposed to waterborne ethynylestradiol.

Studies in mammals have shown that exposure to estrogenic compounds can affect lipid metabolism and plasma concentrations of lipid-soluble vitamins. However, the potential for estrogenic contaminants to induce these effects in fish has not yet been examined. The ability of the estrogen analog ethynylestradiol (EE2) to alter concentrations of the lipid-soluble vitamins A and E in plasma, liver, and kidney was investigated in juvenile lake sturgeon (430 +/- 20 g). The EE2 was delivered to the sturgeon in the tank water at nominal concentrations of 0 (control), 15, 60, or 125 ng EE2/L for a period of 25 d. Concentrations of the egg yolk precursor, vitellogenin, increased dose dependently in plasma. Plasma vitamin E (tocopherol), A1 (retinol), and A2 (dehydroretinol) were elevated by the two highest EE2 treatments compared with the controls. Esterified storage forms of vitamin A were marginally lower in the livers of fish from the highest EE2 dose group, but vitamin E levels in the liver were not significantly affected. Concentrations of vitamin E and vitamin A were significantly depleted in the kidney of fish from the two highest EE2 dose groups. Total lipid content was elevated in the gonad of fish treated with the highest dose of EE2 compared with the controls. Altered lipid and vitamin distribution may be induced by estrogen to facilitate gonadal maturation in sturgeon. Results from these studies indicate that an examination of the implications for vitamin depletion by estrogenic contaminants in juvenile fish is warranted.

Animals↗
PubMed2000

High-resolution localization of Drosophila Spt5 and Spt6 at heat shock genes in vivo: roles in promoter proximal pausing and transcription elongation.

Recent studies have demonstrated roles for Spt4, Spt5, and Spt6 in the regulation of transcriptional elongation in both yeast and humans. Here, we show that Drosophila Spt5 and Spt6 colocalize at a large number of transcriptionally active chromosomal sites on polytene chromosomes and are rapidly recruited to endogenous and transgenic heat shock loci upon heat shock. Costaining with antibodies to Spt6 and to either the largest subunit of RNA polymerase II or cyclin T, a subunit of the elongation factor P-TEFb, reveals that all three factors have a similar distribution at sites of active transcription. Crosslinking and immunoprecipitation experiments show that Spt5 is present at uninduced heat shock gene promoters, and that upon heat shock, Spt5 and Spt6 associate with the 5' and 3' ends of heat shock genes. Spt6 is recruited within 2 minutes of a heat shock, similar to heat shock factor (HSF); moreover, this recruitment is dependent on HSF. These findings provide support for the roles of Spt5 in promoter-associated pausing and of Spt5 and Spt6 in transcriptional elongation in vivo.

Animals↗
PubMed2000

Renal excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine in Wistar rats with increased O(2) consumption due to cold stress.

DNA damage by reactive oxygen species is of special interest in the development of cancer and in aging. The renally excreted amount of 8-oxo-7,8-dihydro-2'-deoxyguanosine (oxo(8)dG) is a potential noninvasive marker of oxidative DNA damage. The respiratory chain of mitochondria is one source for the formation of reactive oxygen species. In the present study we investigated in Wistar rats (n = 7; mean body weight at start, 307.4 +/- 11 g) the effect of an increased O(2) consumption, i.e., energy expenditure, due to cold stress on the renally excreted amount of oxo(8)dG. First, the rats were housed for 4 days at 23.5 degrees C (basic period, BP), and then for 6 days at 10 degrees C (cold stress period, CSP), and finally for 3 days at 23.5 degrees C (recovery period, RP). The O(2) consumption (L O(2)/day/kg weight) was significantly (P < 0.0001) on average 50% higher in CSP (69.0 +/- 3.9) than in BP (45.8 +/- 4.8), and similar in BP and RP (44.3 +/- 5.4). The average renal excretion of oxo(8)dG (pmol/day/kg weight) was significantly (P < 0.025) on average 13% higher in CSP (375.5 +/- 27.7) than in BP (333.2 +/- 47. 4) and similar in BP and RP (331.8 +/- 34.3). Maximum increase in oxo(8)dG excretion of on average 17% was on the third to fifth day of the CSP. This study reveals that an increase in O(2) consumption of 50% resulted in a much lower increase in the renal excretion of oxo(8)dG.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

P-TEFb kinase recruitment and function at heat shock loci.

P-TEFb, a heterodimer of the kinase Cdk9 and cyclin T, was isolated as a factor that stimulates formation of productive transcription elongation complexes in vitro. Here, we show that P-TEFb is located at >200 distinct sites on Drosophila polytene chromosomes. Upon heat shock, P-TEFb, like the regulatory factor HSF, is rapidly recruited to heat shock loci, and this recruitment is blocked in an HSF mutant. Yet, HSF binding to DNA is not sufficient to recruit P-TEFb in vivo, and HSF and P-TEFb immunostainings within a heat shock locus are not coincident. Insight to the function of P-TEFb is offered by experiments showing that the direct recruitment of a Gal4-binding domain P-TEFb hybrid to an hsp70 promoter in Drosophila cells is sufficient to activate transcription in the absence of heat shock. Analyses of point mutants show this P-TEFb stimulation is dependent on Cdk9 kinase activity and on Cdk9's interaction with cyclin T. These results, coupled with the frequent colocalization of P-TEFb and the hypophosphorylated form of RNA polymerase II (Pol II) found at promoter-pause sites, support a model in which P-TEFb acts to stimulate promoter-paused Pol II to enter into productive elongation.

Animals↗
PubMed2000

[New pathophysiologic knowledge about acute pancreatitis].

Induction of acute pancreatitis follows a uniform mechanism independent of the different etiologic factors such as gallstones, alcohol, ischemia, hyperlipidemia, hypercalcemia, hereditary and others. Each cause seems to affect primarily the acinar cell, resulting in premature intracellular activation of trypsinogen and other digestive enzymes. Activated enzymes and oxygen free radicals injure the acinar cell and cause a release of cytokines and vasoactive mediators, attract inflammatory cells and activate the vascular endothelium as well as the expression of adhesion molecules. The disturbance of the pancreatic microcirculation induces a progression from edematous to necrotizing pancreatitis independent of the early intracellular events, including protease activation. Specific therapy must be directed towards microperfusion failure as a secondary pathogenetic step, since the initial enzyme activation and cytokine release is irreversible by the time of clinical presentation. In experimental designs comparable to the clinical situation the following therapeutic principles have proven beneficial: increase of blood fluidity by dextran, inhibition of leukocyte-endothelium interaction by ICAM-1 antibodies, and blockade of local vasoconstriction by endothelin-receptor antagonists.

Acute Disease↗
PubMed2000

Genetic analysis of immunomodulating factors in sporadic Parkinson's disease.

Immunomodulating factors have been shown to play a role in the pathogenesis of Parkinson's disease (PD) by biochemical methods. In order to investigate functionally important genes of the tumor necrosis factor alpha (TNFalpha) pathway we studied the frequency of DNA polymorphisms in the interleukin 6 (IL6), the TNFalpha, and the TNFalpha receptor 1 (TNFR1) genes in 264 sporadic German PD patients and in 183 age and sex matched German healthy controls. Analyzing the TNFalpha-308 polymorphism we found heterozygous individuals carrying alleles 1 and 2 more frequently in patients with a relative risk of 1.56 (p = 0.046, p(c) = 0.13, chi2 = 3.98). In contrast, the frequency of the B/2 haplotype described by the TNFR1-609 and TNFRI+36 polymorphisms was significantly decreased in our PD patients group (p = 0.0097, p(c) = 0.048, chi2 = 6.69) with a relative risk reduced to 0.52. Our results suggest an involvement of immunomodulating factors in the pathogenesis of sporadic PD as revealed by a molecular genetic approach.

Adjuvants, Immunologic↗