Biomedical subjects

R Schulz

Publications and source records attributed to R Schulz.

At least 685 records · Page 38Linked to original sources

PubMedDate not supplied

Increased production of atrial natriuretic peptide in the rat thymus after irradiation.

The rat thymus involutes when exposed to dexamethasone, and this phenomenon is accompanied by a striking increase of ANP localized in thymic macrophages. This study was designed to investigate whether a stimulus, that is X-rays, well known to also cause involution of the thymus, is followed by an elevation of ANP-expression. Rats were irradiated with 4, 6 and 8 Gy, and after 4 days we found a dose-dependent increase (3-, 30- and 40-fold) of mRNA coding for ANP. The corresponding ANP precursor (ANP1-126) has been found elevated 4-, 10-, and 13-fold, respectively. Immunohistochemical analysis of irradiated (6 Gy) tissue revealed heavily IR-ANP positive cells in the cortex, which, due to their morphological and enzyme-histochemical characteristics, were identified as highly phagocytising macrophages. We suggest, thus, that regardless of the stimulus applied (DEX or X-rays) causing the vast cell death in the thymus, the increased ANP-expression is linked to the highly activated phagocytic system of the thymus under these conditions.

Animals↗

PubMedDate not supplied

Endogenous ligands for kappa-opiate receptors.

The receptor preferences of opioids in the mouse vas deferens was tested by means of tolerance and cross-tolerance studies. The preparations were rendered tolerant in situ by superfusion with the kappa-receptor agonist dynorphin and with alpha-neoendorphin, respectively, and set up in vitro in the presence of the respective peptide to maintain tolerance. The investigations revealed strong kappa-agonistic activities both of alpha-neoendorphin and of dynorphin and its fragments 1-13 and 1-11. As the dynorphin chain shortened, the kappa-receptor activity declined and delta-receptor activity became progressively apparent. Interestingly, the octapeptide met-enkephalin[Arg6,Gly7,Leu8], a fragment of the adrenal medulla proenkephalin, also displayed considerable kappa-agonistic properties under the experimental conditions employed. Presumably, the decapeptide alpha-neoendorphin and the octapeptide met-enkephalin[Arg6,Gly7,Leu8] cover in addition to the kappa-receptor population in the MVD further opiate receptors, most probably delta-receptors.

Animals↗

PubMedDate not supplied

Presence of atrial natriuretic peptide-like material in guinea pig intestine.

Acidic extracts of guinea pig jejunum and colon contain atrial natriuretic peptide-like material (IR-ANP) detected by radioimmunoassay after purification by Sephadex G-50 gel filtration. Immunohistochemical analysis of guinea pig colon also revealed IR-ANP to be located directly beneath the lamina muscularis mucosae. High performance gel permeation chromatography (HP-GPC) and reverse phase high performance chromatography (RP-HPLC) of the IR-ANP showed correspondence to the 15 kD ANP precursor molecule (pro-ANP). No low molecular weight forms of ANP were detected. The extracted pro-ANP could be converted to alpha-ANP-like material by incubation with serum or supernatant of colonic homogenate. These data indicate the intestine to be a further site of ANP synthesis.

Animals↗

PubMedDate not supplied

The rat thymus--a site of atrial natriuretic peptide synthesis.

The atrium of the heart has been demonstrated to represent the major site of synthesis of atrial natriuretic peptide (ANP), a potent natriuretic, diuretic and vasoactive hormone. Our recent studies revealed ANP-like material outside the heart, namely, in lymphoid follicles of the intestine and in the thymus, and now we report data demonstrating the thymus as a site of synthesis for ANP. The experimental evidence is as follows: firstly, the immunoreactive material detected corresponds chromatographically with the precursor of ANP. Secondly, the thymus contains mRNA for ANP. Thirdly, immunohistochemistry locates ANP-like material to cortical thymocytes with particularly dense staining in the subcapsular areas of the thymus. Interestingly, both ANP-like material and the mRNA coding for ANP were expressed to a larger extent in newborn rats as compared to adult animals, suggesting that ANP may be involved in the development and/or function of T-cells.

Aging↗

PubMedDate not supplied

Failed surgery for temporal lobe epilepsy: predictors of long-term seizure-free course.

OBJECTIVES: To identify prognostic factors which predict the outcome 2 years after TLE surgery in those patients who were not seizure-free at the 6-month postoperative examination. METHODS: We included 86 postoperative TLE patients who had undergone presurgical evaluation, including video-EEG and high-resolution MRI, and who had seizures between the second and sixth postoperative months. RESULTS: 32% of patients were seizure-free in the second postoperative year. We found that normal MRI findings and secondarily generalized seizures (SGTCS) preoperatively were associated with a non-seizure-free outcome, while rare postoperative seizures and ipsilateral temporal IED with seizure-free outcome. Newly administered levetiracetam showed a significant positive effect on the postoperative outcome independent of other prognostic factors. Five of seven patients who received levetiracetam became seizure-free (p = 0.006). CONCLUSION: One-third of patients who did not become seizure-free immediately after surgery, eventually achieved long-term seizure freedom. We suggest watching for long-term seizure freedom after failed epilepsy surgery especially in patients who had rare postoperative seizures, focal MRI abnormality, ipsilateral temporal spikes, or no SGTCS preoperatively. Levetiracetam may have a positive effect on postsurgical seizures.

Adult↗

PubMedDate not supplied

Effectiveness of low dose captopril versus propranolol therapy in infants with severe congestive failure due to left-to-right shunts.

UNLABELLED: To evaluate the therapeutical effects of the angiotensin converting enzyme inhibitor Captopril to the beta-blocker Propranolol in infants with congestive failure due to pulmonary overcirculation, we retrospectively analysed clinical, neurohormonal and hemodynamic data in 22 infants, 11 of whom were treated with Captopril (Group 1), 11 with Propranolol (Group 2). Age, weight, number of palliative operations, plasma renin activities and pulmonary to systemic flow ratios (3.5 vs. 3.5) were not significantly different prior to Captopril or Propranolol therapy. If treatment with digoxin and diuretics did not succeed, the infants were additionally treated with Captopril (1 mg/kg) for a mean of 7.4 months, or with 1.9 mg/kg Propranolol for 9.2 months. RESULTS: 1 mg/kg Captopril did not effectively suppress angiotensin converting enzyme in the steady state at trough level (92+/-52 vs. 87+/-50 nmol/min/ml). In the Propranolol group, the clinical heart failure score (2.6+/-1.5 vs. 7. 4+/-2.5) and plasma renin activities (14+/-10 vs. 101+/-70 ng/ml/h) were significantly lower, compared to the Captopril group. Length of hospital stay (23+/-9 vs. 52+/-24 days) was lower and weight gain (126+/-38 vs. 86+/-84 g/week) was higher within 3 months after starting Propranolol therapy. Significantly lower left atrial pressures (6.2+/-2.2 vs. 13.4+/-9.2 mmHg) and lower endiastolic ventricular pressures (7.6+/-2.5 vs. 12.6+/-4.0 mmHg) during pre-operative cardiac catheterization indicated a better diastolic ventricular function under chronic Propranolol treatment. CONCLUSION: Although high dose Captopril was not evaluated in this study, when compared to patients on low Captopril dosages, infants who received Propranolol treatment showed improvement in heart failure scores, shorter lengths of hospital stay, lower plasma renin activities and better diastolic ventricular functions.

Angiotensin-Converting Enzyme Inhibitors↗

PubMedDate not supplied

Clinical features and surgical outcome of medial temporal lobe epilepsy with a history of complex febrile convulsions.

PURPOSE: Temporal lobe epilepsy (TLE) is frequently associated with hippocampal sclerosis (HS) and complex febrile convulsions (CFC). The causal relationship between TLE, HS, and CFC is unclear. There is also contradictory data whether CFC-associated TLE is a distinct epilepsy syndrome and has different surgical outcome than other medial TLEs. METHODS: We investigated 133 patients (aged 16-59 years) with HS-associated TLE. Thirty-six patients with CFC (CFC group) versus 97 patients without febrile convulsions (NFC group) were compared for clinical history, video-EEG recorded seizure semiology, and surgical outcome. RESULTS: In the CFC group the right-sided HS (67% versus 32%) occurred more frequently than in the NFC group (P<0.001). The two groups did not differ according to the clinical features, both groups share the typical symptoms and findings of the medial TLE. In the CFC group, seizure-freedom 2 years after surgery was 91%, while in the NFC group it was only 64% (P=0.023). This difference was significant even after considering the other known predictive factors for medial TLE. CONCLUSIONS: Medial TLE with CFC is not a distinct epilepsy syndrome. The surgical outcome, however, is much more favorable in these patients in comparison with medial TLE patients who had no history of febrile convulsions.

Adolescent↗

PubMedDate not supplied

Sonographic evaluation of interdigital neuromas.

The purpose of this study is to evaluate the effectiveness of sonography to accurately identify interdigital neuromas. Twenty patients, all complaining of interdigital neuroma type pain, underwent sonographic evaluation of the symptomatic intermetatarsal space and adjacent interspaces. Each patient subsequently had surgical exploration of the symptomatic site. Fourteen patients had sonographic evidence of neuromas which were confirmed surgically; one patient had sonographic evidence of a neuroma that was not confirmed surgically. The remaining five patients did not have sonographic or surgical evidence of neuroma in spite of clinical signs and symptoms. No adjacent neuromas were appreciated. The correlation of sonography and clinical measurements was determined using Pearson's product moment correlation coefficient (r = 0.804, p < 0.001). Measurements performed with ultrasound were highly correlated with surgical findings. The mean size (standard deviation) of neuromas identified with ultrasound and during surgical inspection was 5.35 mm. (1.36) and 5.43 mm. (1.04). Ultrasound demonstrated a sensitivity of 100% and a specificity of 83.3%. Ultrasound was able to accurately predict the presence, size, and location of Morton's neuromas.

Adult↗

PubMedDate not supplied

Patients' perceived benefit from and satisfaction with asthma-related pharmacy services.

OBJECTIVE: To determine whether patients targeted to receive intervention from an asthma management program reported receiving more services and had greater perceived benefit and satisfaction with those services compared with asthma patients not targeted by the program. DESIGN: Mailed survey. SETTING: Community pharmacy. PATIENTS: 471 community-based patients receiving asthma medications from 44 intervention pharmacies and 1,164 patients from 46 usual care (control) pharmacies. MAIN OUTCOME MEASURES: Five-point agreement scale measuring asthma services received, perceived value of the services, and satisfaction. RESULTS: Usable surveys were received from 39.0% of intervention patients and 42.4% of controls. There were no statistically significant differences between groups in the frequency of provision of listed services. Approximately 60% of respondents from both groups received written materials on asthma medications and 54% received inhaler counseling; both were rated high for perceived benefit. Fewer than 20% reported being counseled about asthma triggers. Fewer than 5% reported pharmacists talking to physicians on their behalf. General satisfaction with pharmacy services was high (78.2% agree or strongly agree), but not statistically different between groups. More than 65% believed that pharmacists spend enough time counseling patients. Several comments indicated that patients did not expect or ask for information because they were unaware that services were available and/or they had already been counseled by their physician. Responses to the statement "my asthma is better controlled because of help given to me by the pharmacist" were equivocal and not different between groups. CONCLUSION: Overall, there were few differences between groups. General satisfaction with pharmacy services is high, but patients' perceived benefit and satisfaction with cognitive services is lower. Increased public awareness of pharmacists' capabilities and a more proactive approach to providing cognitive services is needed.

Adrenergic beta-Agonists↗

PubMedDate not supplied

Coronary microembolization.

Atherosclerotic plaque rupture is a key event in the pathogenesis of acute coronary syndromes and during coronary interventions. Atherosclerotic plaque rupture does not always result in complete thrombotic occlusion of the entire epicardial coronary artery with subsequent acute myocardial infarction; however, in milder forms it may result in the embolization of atherosclerotic and thrombotic debris into the coronary microcirculation. The present report summarizes the available morphologic evidence for coronary microembolization in patients who died of coronary artery disease, especially sudden death. The report then goes on to address the experimental pathophysiology of coronary microembolization in animal models of acute coronary syndromes and heart failure. Finally, the report presents the available clinical evidence for coronary microembolization, highlights its key features--arrhythmias, contractile dysfunction, infarctlets and reduced coronary reserve--and addresses prevention by mechanical protection devices and glycoprotein IIb/IIIa antagonism.

Animals↗

PubMedDate not supplied

Detection of diuretics in horse urine by GC/MS.

The use of diuretics in horses subject to doping control is prohibited. Thus, a sensitive screening procedure is required to identify the chemically different diuretics. We communicate here a method to detect three commonly employed acidic diuretics: bumetanide, ethacrynic acid, and furosemide. A liquid-liquid extraction on Extrelut 3 was performed at weak acidic and basic conditions using ethyl acetate as organic solvent. For analysis by GC, the diuretics were methylated on-column in the presence of MSTFA/TMAH, avoiding the commonly employed highly toxic derivatizing agent methyl iodide. For identification of diuretics, we used a mass selective detector operating in the SIM (selected ion monitoring) mode. Confirmation analysis may be obtained with a full scan run. Recoveries for the individual drugs ranged from 31 to 48% at the 100-ng/mL level for 3 mL urine, using calibration curves of drug standards with linearity from 2.5 to 20 ng injected. The limit of detection amounts to 40 ng/mL for the three diuretics. The method permits rapid and sensitive detection of diuretics in horse urine and is recommended for doping control.

Animals↗

PubMedDate not supplied

Methadone screening of racehorses.

The misuse of opiates in racehorses relates to their effect of increasing locomotor activity. Because methadone, a narcotic analgesic, has been suspected of use as a doping compound in the past, it was added to the list of banned drugs and should be considered in doping control. Because the literature fails to provide information on detection of methadone in blood or urine of horses, an enzyme-linked immunosorbent assay was developed to monitor this narcotic in equine body fluids. Combined with high-performance liquid chromatography, the immunoassay also served to confirm positives indicated by screening. Following intravenous administration of methadone (0.1 mg/kg), the drug was found for up to 24 h in blood but was never identified in urine (10-pg/mL detection limit). Thus, urine is dismissed as a source of methadone control, and the use of blood to screen racehorses for this narcotic analgesic is suggested.

Analgesics↗

PubMedDate not supplied

Endothelin concentration in plasma of healthy dogs and dogs with congestive heart failure, renal failure, diabetes mellitus, and hyperadrenocorticism.

Plasma concentrations of endothelin (ET)-1 and -3 were determined simultaneously in dogs with various pathophysiological conditions, because these peptides may display different pharmacological profiles. The study pays special attention to the characterization of plasma ET immunoreactivity (ET-IR), using high-pressure liquid chromatography (HPLC) analysis with off-line detection by radio-immunoassay (RIA). In most sick dogs evaluated total plasma ET-1-IR concentration did not differ from that of healthy dogs. However, HPLC analysis of their total plasma ET-1-IR revealed distinct ET-IR profiles. Big-ET-1, which is barely detectable in control dogs, does represent the predominant ET in sick dogs. Regardless of the pathophysiological conditions, considerable amounts of high-molecular weight ET-1-IR, most likely aggregated ET-material, was found consistently. With respect to ET-3, we constantly observed moderately increased concentrations, though no major difference of molecular pattern was evident between healthy and sick dogs. The data show a distinct regulation of ET-1 and ET-3 in dogs. Furthermore, specific molecular forms of ET-IR were found to occur in various diseases. The endothelins may therefore prove to be of diagnostic importance in the pathophysiology of vascular diseases.

Adrenal Cortex Diseases↗

PubMedDate not supplied

Evidence for nickel in the soluble hydrogenase from the unicellular green alga Scenedesmus obliquus.

Cultures of the green alga Scenedesmus obliquus were grown in the presence of either the chelating reagent EDTA or NiCl2 in various concentrations and assayed for hydrogenase catalyzed photohydrogen evolution after an anaerobic dark adaptation period. Cultivation of algae in the presence of 100 microM EDTA inhibited the formation of hydrogenase activity by 37%. After a cultivation of the cells in the presence of 5-20 microM NiCl2 photohydrogen evolution was increased by 20-40%. Addition of EDTA up to a final concentration of 1.5 mM had no effect on the activity of hydrogenase in cell-free hydrogenase preparations. Cultures grown in the presence of radioactive 63NiCl2 incorporated 63Ni in a parallel fashion to the cell growth. In radioactive labeled hydrogenase preparations a co-elution of radioactivity and hydrogenase activity could be observed using gel filtration chromatography.

Anaerobiosis↗

PubMedDate not supplied

Purification and characterization of cytochrome c6 from the unicellular green alga Scenedesmus obliquus.

Purification of a soluble cytochrome c6 from the unicellular green alga Scenedesmus obliquus by a simple and rapid method is described. The purification procedure includes ammonium sulfate precipitation and non-denaturating PAGE. The N-terminal sequence of the first 20 amino acids was determined and shows 85% similarity and 75% identity to the sequence of cytochrome c6 from the green alga Monoraphidium braunii. The ferrocytochrome shows typical UV/VIS absorption peaks at 552.9, 521.9 and 415.7 nm. The apparent molecular mass was estimated to be 12 kDa by SDS-PAGE. EPR-spectroscopy at 20 K shows resonances indicative for two distinct low-spin heme forms.

Amino Acid Sequence↗

PubMedDate not supplied

Spray deposition of two insecticides into surface waters in a South African orchard area.

Drift from pesticide spray application can result in contamination of nontarget environments such as surface waters. Azinphos-methyl (AZI) and endosulfan (END) deposition in containers of water was studied in fruit orchards in the Western Cape, South Africa. Additionally, attention was given to the contamination in farm streams, as well as to the resulting contamination of the subsequent main channel (Lourens River) approx. 25 km downstream of the tributary stream inlets. Spray deposit decreased with increasing distance downwind and ranged from 4.7 mg m(-2) within the target area to 0.2 mg m(-2) at 15 m downwind (AZI). Measured in-stream concentrations of both pesticides compared well with theoretical values calculated from deposition data for the respective distances. Furthermore, they were in the range of values predicted by an exposure assessment based on 95th-percentile values for basic drift deposition (German Federal Biological Research Centre for Agriculture and Forestry [BBA] and USEPA). Pesticide deposition in the tributaries was followed by a measurable increase of contamination in the Lourens River. Mortality of midges (Chironomus spp.) exposed for 24 h to samples obtained from the AZI trials decreased with decreasing concentrations (estimated LC50 from field samples = 10 microg L(-1) AZI; lethal distance: LD50 = 13 m). Mortality in the tributary samples averaged 11% (0.5-1.7 microg L(-1) AZI), while no mortality was discernible in the Lourens River samples (0.041 microg L(-1)). The sublethal endpoint failure to form tubes from the glass beads provided was significantly increased at all sites in comparison with the control (analysis of variance [ANOVA], Fisher's protected least significant difference [PLSD], p < 0.01).

Agriculture↗

PubMedDate not supplied

Pyrogallol poisoning of pigeons caused by acorns.

Green acorns are known to contain high concentrations of pyrogallol. Here, we describe an extended case report of two pigeons found dead with a filled muscular stomach of acorns. The following pathologic findings were observed: irritation of mucosal membranes in the gastrointestinal tract, blackish discolored chyme, hyperemic organs, and general edemas. The muscular stomach (ventriculus) was filled with pieces of acorns, and the abdominal cavity contained bloody aqueous fluid. In order to uncover the cause of death, we determined pyrogallol in liver and kidney of one dead pigeon and in ventriculus contents of both pigeons by gas chromatography/mass spectrometry. A further aim of our study was to compare pathologic findings and pyrogallol concentrations in kidney, liver, and ventriculus of poisoned pigeons with those of healthy pigeons. The pyrogallol concentrations in samples of dead pigeons were 16-1200-fold higher than in control animals fed grass and maize-corn. Altogether, the acorn-filled ventriculus, the pathologic findings, the well nourished state, and the high pyrogallol concentrations in the dead pigeons suggest an acute pyrogallol poisoning by acorn. With respect to controls, we conclude that pyrogallol concentrations of 6 ng/g of kidney, 8 ng/g of liver, and 2 ng/g of gastric content do not affect the health of pigeons.

Animals↗

PubMedDate not supplied

[Detection of levamisole and ivermectin in organ samples from a dead collie].

A collie, known for its breed-dependent adverse reaction to ivermectin, was without any clinical signs. The dog was prophylactically treated with 3 mg/kg KG (s.c.) of levamisole. Within 15 minutes, the dog showed convulsions, vomitus, and dyspnea, and perished 2.5 hours after injection of the drugs. The pathological findings were not informative as to the cause of death, and with regard to the adverse reactions, additional application of ivermectin was not excluded. Therefore, organ samples were submitted for toxicological analysis of both levamisole and ivermectin. For detection of levamisole and ivermectin, modified GC/MS and HPLC procedures were developed. Concentrations up to 535 micrograms levamisole and up to 26 ng ivermectin were found per g tissue. Both analytical methods are sensitive enough to detect these drugs after application of low doses. This study elucidates that combination of low-dosed ivermectin and levamisole is no recommendable means against adverse effects of ivermectin, with respect to collies. Moreover, the synergistic effects of ivermectin and levamisole suggests the same drug incompatibility in other dog breeds and animal species.

Adipose Tissue↗