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Biomedical subjects

A Wolf

Publications and source records attributed to A Wolf.

At least 109 records · Page 6Linked to original sources
PubMed1999

Angiotensinogen M235T polymorphism is associated with plasma angiotensinogen and cardiovascular disease.

BACKGROUND: Genes encoding components of the renin-angiotensin system have been associated with elevated blood pressure (BP) and an increased risk of coronary artery disease. To explore the role of the angiotensinogen (AGT) gene in coronary atherosclerosis and thrombosis, we studied the effect of the AGT M235T gene variant on plasma AGT levels and BP in patients with coronary artery disease and in the subgroup of survivors of myocardial infarction as compared with angiographically defined control subjects. METHODS AND RESULTS: This was a case-control study of 301 white male subjects examined at Frankfurt University medical center. Plasma AGT levels increased stepwise according to the number of T235 alleles present (no T235 allele, 14.8 +/- 3.9 nmol/L; 1 allele, 15.7 +/- 5.1 nmol/L; 2 alleles, 17.3 +/- 4.7 nmol/L; P =.006). In a multivariate model, circulating AGT emerged as the most important predictor of diastolic pressure (P =.001). In addition, AGT M235T gene polymorphism remained a significant predictor of diastolic BP in a multivariate model adjusted for age, body mass index, fasting glucose, apolipoprotein B, presence of coronary artery disease, and treatment with antihypertensive agents ( P <.05). Finally, homozygosity for T235 was associated with increased univariate risk of coronary artery disease and myocardial infarction (odds ratio estimates 1.5; 95% confidence intervals 1.1 to 2.1, P =.03, and 1.0 to 2.1, P =.05, respectively). CONCLUSIONS: The significant relations observed between the AGT M235T variant, its protein product, and the cardiovascular disease phenotypes provide evidence for a possible role of elevated circulating AGT in the pathogenesis of coronary artery disease.

Alleles↗
PubMed1999

Spinal epidural abscess: contemporary trends in etiology, evaluation, and management.

BACKGROUND: Despite advances in neuroimaging and neurosurgical treatment, spinal epidural abscess remains a challenging problem; early diagnosis is often difficult and treatment is delayed. Optimal management is unclear, and morbidity and mortality are significant. To define contemporary trends in etiology and management, and establish diagnostic and therapeutic guidelines, we reviewed our 10-year experience with spinal epidural abscess. METHODS: We examined medical records, laboratory data, radiological (CT and MRI) studies, and operative reports from 75 cases of spinal epidural abscess between 1983 and 1992. Demographic characteristics, frequency, clinical features, pathogens, risk factors, surgical and medical treatment, and outcome were analyzed. RESULTS: We found a significant increase in the frequency of spinal epidural abscess over the 10-year period (p-value = 0.0195). Intravenous drug abuse was present in 28 patients (33%), diabetes mellitus in 22 patients (27%), and prior spinal surgery in 11 patients (17%). Back pain, progressive neurologic deficit, and low grade fever remained the distinguishing diagnostic features. Erythrocyte sedimentation rate was elevated in 48 of 50 patients (95%); peripheral leukocyte count was elevated in 45 patients (60%). MRI was the most effective technique for diagnosing spinal epidural abscess, revealing or suggesting the diagnosis in all 59 patients (100%) studied. Sites of spinal epidural abscess were equally distributed along the spinal axis. Staphylococcus aureus was the predominant organism (67% of patients, with 15% having a methicillin-resistant strain); 8% of patients had Streptococcal species. Most patients had open surgical drainage followed by prolonged antibiotic treatment; 22 patients were managed with antibiotics alone; 50 patients (66%) had a good clinical outcome after treatment. Multiple medical problems, prior spinal surgery, and methicillin-resistant Staphylococci were correlated with a significantly worse outcome. CONCLUSIONS: The frequency of diagnosis of spinal epidural abscess is increasing. To prevent serious morbidity and mortality, early diagnosis is essential. Patients with localized back pain who are at risk for developing such abscesses or who have an increased erythrocyte sedimentation rate and/or neurologic deficit should have an immediate MRI scan with contrast enhancement. Surgical drainage and prolonged antibiotic use are the cornerstones of treatment, although selected patients may be treated conservatively.

Abscess↗
PubMed1999

Lack of association between a human beta-2 adrenoceptor gene polymorphism (gln27glu) and morbid obesity.

OBJECTIVE: To determine the frequency of the gln27glu polymorphism in the beta-2 adrenoceptor gene in patients with morbid obesity. SUBJECTS: 243 patients with morbid obesity (mean body mass index 51. 6) and 199 healthy blood donors. RESULTS: The same frequency, 0.42, of the glu allele was observed in both groups. Neither the incidence in obese women (0.41, n=197) compared to control women (0.43, n=61), nor that in obese men (0.44, n=46) compared to control men (0.41, n=138) was significantly different. The difference in frequency between obese men and women, 0.44 vs 0.41 was not significant (P=0. 68). Genotype information from the families of 18 of the obese patients showed no association between the glu27 allele and BMI. CONCLUSIONS: We find no evidence for a role of the glu27 variant in the beta-2 adrenoceptor gene in the development of morbid obesity.

Alleles↗
PubMed1999

Stanniocalcin 2: characterization of the protein and its localization to human pancreatic alpha cells.

Stanniocalcin (STC) is a hormone that was originally identified in fish, where it inhibits calcium uptake by the gills and gut and stimulates phosphate adsorption by the kidney. Recently, two mammalian homologues of stanniocalcin were identified. The first (STC1) shows 61% identity to the fish stanniocalcins and appears to have a function similar to that of the fish stanniocalcins. The second homologue (STC2) is 30-38% identical to the fish stanniocalcins, and is characterized by unique cysteine and histidine motifs that are not found in the other stanniocalcins. We purified both the native hamster and recombinant human STC2 proteins and obtained a partial amino acid sequence of the hamster protein. Both proteins behave as a disulfide bonded homodimer, which undergoes post-translational modification(s). The STC2 gene was localized to human chromosome 5q35. Northern blot analysis revealed that the primary site of human STC2 production is the pancreas, and immunostaining localized the STC2 protein to a subpopulation of cells in the islet. Double immunostaining for STC2 and either insulin or glucagon revealed that STC2 protein is found in the alpha cells, but not the beta cells. We speculate that STC2 may play a role in glucose homeostasis.

Amino Acid Sequence↗
PubMed1999

Neurodevelopmental outcome at early school age of children born to mothers with gestational diabetes.

AIMS: To study the metabolic derangements in the second half of pregnancy caused by gestational diabetes, on the long term development of children. METHODS: The neuropsychological function of 32 school age children born to 32 mothers with well controlled gestational diabetes and 57 control children matched by age, birth order, and parental socioeconomic status was studied. RESULTS: There were no differences in head circumference and height, but the children born to diabetic mothers were heavier. The verbal IQ scores of index children below the age of 9 years were lower than those of control children. No differences were found between the groups in various sensory and motor functions and in the Touwen and Prechtl neurological test. The young index group children performed less well than controls in fine and gross motor functions, as observed on the Bruininks-Oseretzky test of motor proficiency. The scores of young children born to mothers with gestational diabetes were also lower than controls on the Pollack tapper test, and there were more index group children who scored abnormally on the parents' Conners questionnaire. No correlation was found between the performance of the index group children on various neurodevelopmental tests and the severity of perinatal complications. The differences tended to disappear with age. CONCLUSIONS: Gestational diabetes, as a result of the metabolic abnormalities in the second half of pregnancy, induces long term minor neurological deficits which are more pronounced in younger children. There does not seem to be any direct relation between the appearance of congenital anomalies and neurodevelopmental outcome.

Child↗
PubMed1999

Parallel Synthesis and Testing of Catalysts under Nearly Conventional Testing Conditions.

Acceleration by one to two orders of magnitude for catalyst development without much loss of information: Parallelized synthesis and screening has been used to evaluate catalysts for the room-temperature oxidation of CO. The overall process was highly reproducible, and the data quality is comparable to that of conventional testing. The graph shows the results of parallel testing of Au/Co(3)O(4) catalyts at 25 degrees C (y=yield of CO(2)).

Journal Article↗
PubMed1998

Malaria infection of the mosquito Anopheles gambiae activates immune-responsive genes during critical transition stages of the parasite life cycle.

Six gene markers have been used to map the progress of the innate immune response of the mosquito vector, Anopheles gambiae, upon infection by the malaria parasite, Plasmodium berghei. In addition to four previously reported genes, the set of markers included NOS (a nitric oxide synthase gene fragment) and ICHIT (a gene encoding two putative chitin-binding domains separated by a polythreonine-rich mucin region). In the midgut, a robust response occurs at 24 h post-infection, at a time when malaria ookinetes traverse the midgut epithelium, but subsides at later phases of malaria development. In contrast, the salivary glands show no significant response at 24 h, but are activated in a prolonged late phase when sporozoites are released from the midgut into the haemolymph and invade the glands, between 10 and 25 days after blood feeding. Furthermore, the abdomen of the mosquito minus the midgut shows significant activation of immune markers, with complex kinetics that are distinct from those of both midgut and salivary glands. The parasite evidently elicits immune responses in multiple tissues of the mosquito, two of which are epithelia that the parasite must traverse to complete its development. The mechanisms of these responses and their significance for malaria transmission are discussed.

Amino Acid Sequence↗
PubMed1998

Attenuation of the lordosis-inhibiting effects of 8-OH-DPAT by TFMPP and quipazine.

Regularly cycling, proestrous female rats received infusions of 200 ng of the serotonin (5-HT) 1A receptor agonist, (+/-) 8-hydroxy 2-(di-n-propylamino) tetralin-HBr (8-OH-DPAT), or 200 ng 8-OH-DPAT and 1000 or 2000 ng of N-(3-trifluoro-methylphenyl) piperazine hydrochloride (TFMPP) or 2-(1-piperazinyl) quinoline dimaleate (quipazine). Infusions were made bilaterally into the ventromedial nucleus of the hypothalamus (VMN). Animals receiving 200 ng 8-OH-DPAT exhibited a decline in lordosis behavior following infusion. Rats receiving 8-OH-DPAT and 1000 or 2000 ng quipazine or TFMPP were protected from the lordosis-inhibiting effects of 8-OH-DPAT, alone. Although both quipazine and TFMPP act on multiple 5-HT receptors, they overlap in their agonist action at 5-HT2 receptors. Consequently, these results provide further evidence supporting the contention that within the VMN, both 5-HT1A and 5-HT2 receptor subtypes contribute to the modulation of lordosis behavior in the female rat. The data are discussed in terms of the relative potency of 5-HT at 5-HT receptors mediating inhibition and facilitation of lordosis behavior.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1998

Dissociative recombination of HD+ in selected vibrational quantum states

Rate coefficients for dissociative recombination of HD+ in selected vibrational states have been measured by a combination of two molecular fragment imaging methods by using the heavy-ion storage ring technique. Recombination fragment imaging yields state-to-state reaction rates. These rates are converted to rate coefficients by using vibrational level populations of the stored ion beam, derived from nuclear coordinate distributions measured on extracted ions. The results show strongly increasing rate coefficients for high vibrational excitation, where additional dissociation routes open up, in agreement with a theoretical calculation. Very low rate coefficients are found for certain, isolated vibrational states.

Journal Article↗
PubMed1998

Thermal control of drug release by a responsive ion track membrane observed by radio tracer flow dialysis.

The combination of a responsive hydrogel with a rigid porous supporting structure yield a membrane with high mechanical strength and high on-off-permeability ratio. A membrane consisting of an ion track filter with a thermally responsive lining was prepared by penetrating a 19 micron thick foil of poly(ethylene terephthalate) (PET) with swift heavy ions at a fluence of 5 x 10(5) ions/cm2, followed by etching of the ion tracks to generate an ion track filter with 2.9 micron pore diameter, onto which a thin layer of poly(N-isopropylacrylamide) (NIPAAm) hydrogel was grafted. It was revealed that the mass flow of various molecules (water, chloride-, choline+, insulin, and albumin) through the membrane could be thermally controlled. The on-off-permeability ratio ranged between 3 and 10 increasing with molecular weight. Over a storage time of 5 months the permeabilities varied up to a factor of 2.6, while the on-off-permeability ratio and temperature sensitivity remained practically constant.

Drug Delivery Systems↗
PubMed1998

Facilitation of female rat lordosis behavior by hypothalamic infusion of 5-HT(2A/2C) receptor agonists.

Ovariectomized rats were hormonally primed with 0.5 microg estradiol benzoate and 500 microg progesterone to produce two groups of rats differing in their lordosis behavior. Females with a lordosis to mount (L/M) ratio < 0.5 were used to test the hypothesis that 5-HT(2A/2C) receptor agonists could facilitate lordosis behavior. Females with L/M ratios > or = 0.5 were used to evaluate the potential suppressive effect of 5-HT(2A/2C) receptor compounds. Lordosis behavior was examined following bilateral infusion of drugs into the ventromedial nucleus of the hypothalamus (VMN). Drugs examined were the 5-HT(2A/2C) receptor agonist, (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI), the 5-HT(2A/2C) receptor antagonist, 3-[2-[4-(4-fluorobenzoyl)-1-piperdinyl]ethyl]-2,4(1H,3H)-quinazoli nedione tartrate (ketanserin tartrate), and the non-selective 5-HT receptor agents, 2-(1-piperazinyl)quinoline dimaleate (quipazine) and N-(3-trifluoromethylphenyl)piperazine HCl (TFMPP). Drugs with agonist action at 5-HT(2A/2C) receptors increased lordosis behavior in rats with low sexual receptivity. The 5-HT(2A/2C) receptor antagonist, ketanserin, inhibited lordosis behavior in sexually receptive rats. DOI attenuated the lordosis-inhibiting effect of ketanserin, but ketanserin was less effective in preventing DOI from increasing lordosis behavior. These results strengthen prior inferences that activation of 5-HT(2A/2C) receptors can facilitate lordosis behavior and that the VMN is one site at which such facilitation can occur.

Amphetamines↗
PubMed1998

Myocardial ischemia and infarction due to multiple coronary-cameral fistulae: two case reports and review of the literature.

The functional significance of coronary-cameral fistulae, and the effect of these arterial anomalies upon effective coronary blood flow, continue to be debated. Two cases of coronary cameral fistulae, each of which illustrates the likelihood of an ischemic substrate, are herein presented, along with a review of the relevant literature regarding this disorder.

Aged↗
PubMed1998

Use of assumed versus measured oxygen consumption for the determination of cardiac output using the Fick principle.

Assumed oxygen consumption (VO2) is increasingly used as a convenient surrogate for measured VO2 for calculation of cardiac output. This substitution is often based on empirical formulae, previously validated only in relatively young patients. To assess the inaccuracy introduced by extrapolating these formulae to older patients, we compared measured VO2 with assumed VO2 in 57 patients. VO2 was measured using an open circuit analyzer. Assumed VO2 was calculated according to the LaFarge or Bergstra formulae. Agreement between both methods was assessed according to the method of Bland and Altman. The mean difference of measured VO2 minus assumed VO2 was 7.9 ml/min/m2 (P < 0.02) using the LaFarge formula, and -15.6 ml/min/m2 (P < 0.0002) using the Bergstra formula across a range of measured VO2 from 70 to 176 ml/min/m2. A systematic error was introduced by assumed VO2 from both formulae of underestimating higher and overestimating lower values of VO2, resulting in poor overall agreement with measured VO2. The same error and poor agreement was found when analyzing subgroups of patients > or =60 or <70 years of age. In summary, use of assumed VO2 introduces large, unpredictable errors in adult patients, suggesting requirement for measurement of VO2 when calculating cardiac output.

Adolescent↗
PubMed1998

Effect of phorbol ester (PMA) on antioxidant enzyme expression in TGF-beta 1-induced apoptosis in primary cultures of hepatocytes.

Apoptosis has been documented as a fundamental component of the life cycle of many cell types. One of the characteristics of this process is the cleavage of genomic DNA into oligonucleosomal fragments. The multifunctional cytokine TGF-beta 1 has been described to induce apoptosis in cultured hepatocytes although in this condition DNA fragmentation has not been detected. We investigated whether TGF-beta 1-induced apoptosis was associated with DNA fragmentation and was affected by PMA. Agarose gel electrophoresis of TGF-beta 1-treated hepatocytes shows a typical ladder-like pattern of DNA fragments and PMA, a selective stimulator of protein kinase C, diminishes the DNA fragmentation and cell death. It has been described that the antioxidant enzyme systems play an important role in the control of apoptosis and that the apoptogenic ability of TGF-beta 1 is through the inhibition of antioxidant enzyme expression in cultured hepatocytes [8]. However, PMA does not induce significant changes levels of manganese superoxide dismutase, copper-zinc superoxide dismutase and catalase mRNAs. Our data reveal that the attenuation of TGF-beta 1-induced DNA fragmentation by PMA is not associated with changes in the expression of antioxidant systems and is probably due selectively to the stimulation of protein kinases C.

Animals↗
PubMed1998

Early child-care selection: variation by geographic location, maternal characteristics, and family structure.

More than half of all U.S. infants and toddlers spend at least 20 hr per week in the care of a nonparent adult. This article uses survival analysis to identify which families are most likely to place their child in care and the ages when these choices are made, using data from a national probability sample of 2,614 households. Median age at first placement is 33 months, but age varies by geographic region, mother's employment status during pregnancy, mother's education level, and family structure (1 vs. 2 parents, mother's age at 1st birth, and number of siblings). Controlling for these effects, differences by race and ethnicity are small. Implications for studies of child-care selection and evaluations of early childhood programs are discussed.

Adolescent↗
PubMed1998

The outcome of children requiring admission to an intensive care unit following bone marrow transplantation.

We report the results of a retrospective study of the role of intensive care unit (ICU) admission in the management of 367 children who underwent bone marrow transplantation (BMT) at a tertiary referral institution. 39 patients (11%) required 44 ICU admissions for a median of 6 d. 70% received marrow from unrelated donors, half of which were mismatched; 80% had leukaemia and two-thirds were considered high-risk transplants. Respiratory failure was the major reason for admission to ICU. 75% of admissions required mechanical ventilation (for a median of 5 d) and 20 patients had lung injury as defined by the criteria of the Seattle group. None of 11 patients with proven viral pneumonitis survived (P = 0.06) and only one of 20 patients with lung injury survived (P < 0.01). Six of seven patients with a primary neurological problem survived (P < 0.001); these appear to represent a good outcome group. Age, the presence of graft-versus-host disease, the use of inotropes, isolated renal or hepatic impairment, and paediatric risk of mortality (PRISM) score were not predictive of outcome. In total, 12 patients (27% of admissions) survived and were discharged from hospital 30d or more after admission and eight (18%) survived >6 months. ICU admission can be beneficial to selected children post-BMT but it may be less useful in proven viral pneumonitis. Where mechanical ventilation is required, the duration of this support should be limited unless there is rapid improvement.

Acute Disease↗
PubMed1998

The effect of non-genotoxic carcinogens, phenobarbital and clofibrate, on the relationship between reactive oxygen species, antioxidant enzyme expression and apoptosis.

Phenobarbital and clofibrate, two non-genotoxic carcinogens, have been investigated regarding the relationship between reactive oxygen species, antioxidant enzyme expression and apoptosis in primary cultures of rat hepatocytes. Low toxicity concentrations, 200 and 100 microg/ml for phenobarbital and clofibrate respectively, were used to examine their effect on spontaneous or transforming growth factor beta1 (TGFbeta1)-induced apoptosis and on the expression of antioxidant defence enzymes (superoxide dismutases and catalase). The increased incidence of apoptotic nuclei was visualized in TGFbeta1-treated cultures with the fluorescent dye Hoechst 33258 and was quantified under all experimental conditions by measurement of the hypodiploid peak in DNA histograms obtained by flow cytometry. Both substances, when added separately to hepatocyte cultures and incubated for 24 and 48 h, significantly diminished spontaneous apoptosis and exhibited a slight suppression of TGFbeta1-induced apoptosis. Endogenous peroxide production by hepatocytes increased with TGFbeta1, phenobarbital or clofibrate and the increase was greater with phenobarbital and in the presence of TGFbeta1 with both drugs. Gene expression of catalase and Mn- and Cu,Zn superoxide dismutases (SOD) was evaluated by northern blot analysis of hepatocytes incubated in the presence of phenobarbital or clofibrate with or without TGFbeta1 and the following differences were detected: phenobarbital induced a significant decrease in both dismutases (to 56%, P < 0.05, and 55%, P < 0.05, for Mn- and Cu,Zn-SOD respectively) and a 2-fold increase (P < 0.01) in catalase; clofibrate induced a slight decrease in both SODs and a 4-fold increase (P < 0.05) in catalase; TGFbeta1 significantly decreased to 37% (P < 0.05) expression of catalase while not significantly affecting expression of both SODs. We conclude that inhibition of spontaneous apoptosis induced by either phenobarbital or clofibrate is accompanied by increases in the endogenous levels of peroxides and by significant induction of catalase gene expression. Furthermore, the lack of effect of both compounds on TGFbeta1-induced apoptosis could be a consequence of the inability of these two compounds to counteract the depressing effect of TGFbeta1 on expression of catalase.

Animals↗