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Biomedical subjects

B Schmidt

Publications and source records attributed to B Schmidt.

At least 649 records · Page 36Linked to original sources
PubMedDate not supplied

Stress-induced changes in the function of the parasympathetic nervous system are mimicked by blocking GABA in the CNS of the cat.

The purpose of this study was to determine the effect of blockade of receptors for gamma-aminobutyric acid (GABA) in the forebrain, on vagal activity to the stomach and heart. This was done by injecting bicuculline (50 micrograms) into the lateral ventricle of the brain and restricting the drug to the forebrain ventricles by cannulating the cerebral aqueduct. Studies were performed in chloralose-anesthetized cats and gastric motility was monitored using extraluminal force transducers, sutured to the antrum and pylorus. Cardiac vagal activity was determined by noting the sinus bradycardia that developed from activation of the baroreceptor reflex induced by phenylephrine. Administration of bicuculline into the lateral ventricle of 7 animals produced increases in the minute motility index of 5.3 +/- 0.8 (antrum) and 13.9 +/- 2.1 (pylorus). This was associated with inhibition of baroreceptor-induced vagal bradycardia (i.e. -38 +/- 6.4 beats/min before bicuculline and -7.7 +/- 5.7 beats/min after bicuculline). These data indicate that a GABAergic mechanism in the forebrain may be important for controlling vagal outflow to both the stomach and the heart.

Animals↗
PubMedDate not supplied

CRF in the paraventricular nucleus of the hypothalamus stimulates colonic motor activity in fasted rats.

The influence of corticotropin releasing factor (CRF) microinjected into the paraventricular nucleus of the hypothalamus (PVN) on colonic motility was investigated in conscious, fasted rats. Rats were chronically implanted with a bilateral guide cannula into the PVN and a catheter into the proximal colon to record motor activity manometrically. Microinjection of CRF (0.6 nmol/rat) into the PVN increased both phasic and tonic motor activity in the proximal colon. Atropine sulfate (1 mg/kg, IP) completely abolished the colonic motor response to CRF. Microinjection of CRF (0.6 nmol/rat) into sites outside of the PVN did not modify colonic motor activity. These data show that CRF acts in the PVN to stimulate tonic and phasic motor activity in the proximal colon. Corticotropin releasing factor action is site specific and mediated through cholinergic pathways.

Animals↗
PubMedDate not supplied

[Validity and reproducibility of osteodensitometric DEXA-measurements following total hip endoprosthesis].

For the determination of reproducibility of bone densitometric measurements we performed a measurement according to the DEXA- method. 35 patients after implantation of total hip replacement were examined with a Lunar DPX-L. We received a maximum reproduction error of 1.2% according to the GRUEN-analysis. The operated hip of 17 patients showed an increase in bone density between 5 and 18% by the implantation of an arthroplasty compared to the preoperative values. The non-operated prosthesis-corrected hip showed a reproduction error of 3.8% in ROI 1 in 17 patients, otherwise a maximum of 1.3%. Considering an interfemoral difference in bone density of up to 20%, differences in periprosthetic bone density of up to 40% compared to the contralateral side can be within the normal range in a retrospective measurement. Therefore retrospective determination of bone density after cementless hip arthroplasty only is of limited value. Only prospective analysis can provide reliable information about the actual loss of bone density.

Absorptiometry, Photon↗
PubMedDate not supplied

Gabapentin (Neurontin) as add-on therapy in patients with partial seizures: a double-blind, placebo-controlled study. The International Gabapentin Study Group.

A multicenter, double-blind, randomized, placebo-controlled study evaluated the efficacy and safety of gabapentin (Neurontin, GBP) as add-on therapy in 272 patients with refractory partial seizures who were receiving one to two standard antiepileptic drugs (AEDs). Efficacy assessments compared the frequency of partial seizures during the 12-week treatment phase (T) and the 12-week baseline period (B). The primary analysis compared data for patients receiving GBP 900 mg/day with placebo; the GBP 1,200-mg/day group provided dose-response data. Efficacy criteria were percentage of change in seizure frequency (PCH), responder rate (percentage of patients with > or = 50% reduction in seizure frequency), and response ratio, where RRatio = (T-B)/(T + B). Median PCH was -21.8% in the 900-mg/day group and -17.8% in the 1,200-mg/day group as compared with -0.3% in the placebo group. Responder rate was 22.9% in the 900-mg/day group and 10.1% in the placebo group (p = 0.020, Fisher's exact test). Adjusted mean RRatio was -0.136 in the 900-mg/day group and -0.025 in the placebo group (p = 0.0046, analysis of variance ANOVA). Results showed slightly greater improvement for the 1,200-mg/day than for the 900-mg/day group (RRatio = -0.157, responder rate 28.0%). Adverse events (AE) occurred in 69% of patients in the 900-mg/day group and in 64% in the 1,200-mg/day group as compared with 52% in patients receiving placebo as add-on therapy. The most frequent AE among patients treated with GBP were somnolence, dizziness, and fatigue. Clinical laboratory evaluations showed no clinically important trends and no evidence of hepatic or hematopoietic effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMedDate not supplied

Regulation of CD95 (Apo-1/Fas) ligand and receptor expression in human embryonal carcinoma cells by interferon gamma and all-trans retinoic acid.

Expression of CD95 (Apo-1/Fas) ligand and its two receptor isoforms, in response to all-trans retinoic acid and interferon gamma (IFNgamma), was analyzed atthe mRNA and protein levels in human Tera-2 embryonal carcinoma cells. Exposure of Tera-2 cells to all-trans retinoic acid for up to 16 days led to a decrease of CD95 ligand expression when compared to the control conditions, whereas expression of both CD95 isoforms increased. These changes were functionally significant since Tera-2 cells treated with all-trans retinoic acid for six to 16 days were more susceptible to CD95-mediated apoptosis. On the other hand, Tera-2 cells lost their capacity to induce apoptosis in CD95 receptor bearing Jurkat T lymphocytes after six days of incubation with all-trans retinoic acid. When Tera-2 cells were treated with IFNgamma, expression of CD95 ligand and both CD95 receptor isoforms increased within 24 hours. Tera-2 cells were then more susceptible to CD95 mediated apoptosis but also killed more CD95 receptor bearing Jurkat T lymphocytes via CD95 ligation compared to the control conditions. The results are indicative of differential regulation of CD95-mediated apoptosis by all-trans retinoic acid and IFNgamma in Tera-2 embryonal carcinoma cells, with likely impact on antitumor immunity.

Apoptosis↗
PubMedDate not supplied

Light-dependent interactions of phenazine methosulfate with 3-(3,4-dichlorophenyl)-1,1-dimethylurea-poisoned chloroplasts.

The chlorophyll fluorescence of isolated chloroplasts in the presence of phenazine methosulfate (PMS) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) can be quenched in a light-depentdent reaction. This phenomenan has been studied and the following observations were made: 1. Quenching occurs under non-phosphorylating conditions and is stimulated by Mg2+ ions. 2. Under the same conditions, a light-dependent, Mg2+ stimulated transient decrease of absorption at change and binding of PMS. Others, such as methylamine, ammonia, gramicidin and nigericin do not. It is suggested that fluorescence quenching, transient absorption change and binding of PMS are casually related. The concept, postulated by others, that a high-energy state of the chloroplast membrane is involved in the fluorescence lowering is questioned.

Chloroplasts↗
PubMedDate not supplied

Acyl chain specificity and kinetic properties of phospholipase A1 and A2 of bone marrow-derived macrophages.

The fatty acyl specificity of phospholipase A1 and A2 in homogenates of mouse bone marrow-derived macrophages was determined using phosphatidylcholine and phosphatidylethanolamine of different acyl chain composition. Phosphatidylcholine with arachidonoyl at position 2 was cleaved preferentially by an alkaline phospholipase A2 (pH-optimum 9.0) leading to selective liberation of arachidonic acid. In contrast, phosphatidylcholines with oleoyl or linoleoyl at position 2 were degraded mainly by an acid phospholipase A1 (pH-optimum 4-5) resulting in a conservation of these fatty acids esterified in lysophosphatides. Substrate kinetics of the alkaline phospholipase A2 revealed a 30 fold higher affinity (Km = 3.8 X 10(-7) M) for 1-acyl-2-arachidonoyl-glycerophosphocholine compared to 1-acyl-2-oleoyl-glycerophosphocholine. The kinetic data were not influenced by endogenous lipids indicating that exogenous substrates do not equilibrate with cellular lipids. These results are suitable to explain a selective liberation of arachidonic acid from a mixture of phospholipids.

Animals↗
PubMedDate not supplied

Four adult hemoglobin types in one mulatto family.

The studied family showed the presence of four different types of hemoglobin. The family member who gave rise to this study (=propositus) presented Hb C and the hybrid Hb CG-phila. The propositus has three children, all of which have Hb AC; none of the family members showed any clinical symptoms. The investigation of the hemoglobin arose from the finding of target red cells in a blood test done during the pre-operatory examination for lower limb varicose vein stripping. The hybrid Hb CG-phila is due to two gene pairs, each of which with individual expression, determining the synthesis and the particular type subunits. The hybrid Hb CG-phila is formed by the combination velocity of the subunits alpha 2G-phila beta 2; therefore the proportion of the hybrid Hb CG-phila is lower than Hb G-phila and Hb C. The identification and molecular characterization of Hb G-phila showed the position alpha 2(68) Asn-->Lys beta 2 and Hb C showed alpha 2 beta 2(6) Glu-->Lys.

Adult↗
PubMedDate not supplied

[Intrauterine energetic malnutrition in rats: muscle skeletal changes in the 1st and 2nd generations]

OBJECTIVE: To study by histochemical analysis the skeletal muscle in malnourished newborn rats submitted to intrauterine malnutrition. METHODS: 90 days old female, Wistar EPM-1 rats, with 200 -/+ 20g body weight, malnourished during the gestation period were studied. At the 21th day of gestation, muscular biopsy was performed in the biceps bracchi of the newborns, obtained by cesarean (1st generation). One group of newborn intrauterine malnourished rats had nutritional recovery after birth by staying six/lactating rat and by free feeding up to the 90th day of life, when the females became pregnant and their offspring formed the 2nd generation. RESULTS: Weight gain during gestation and body weight of the newborn were significantly different when each malnourished group was compared to its respective control. The muscular biopsies of the malnourished newborns presented tissue involvement, characterized by loss of predominance of type II fibres, low oxidative activity, lessening of muscular fiber diameter, proliferation of intersticial tissue, and edema. In the 2nd generation, the newborns presented adequate body weight, but maintained muscular tissue involvement, with lessening of predominance of type II fibers, reduction of muscular fiber diameter, low oxidative activity, increase of intersticial space, necrosis, but without edema. CONCLUSION: The energetic malnutrition affects the skeletal muscle at birth, when it occurs during miogenesis, in both 1st and 2nd generation, maintaining permanent or temporary lesions in the muscular tissue.

Journal Article↗
PubMedDate not supplied

Perioperative brachytherapy as an additional therapeutic option in patients with renal cell carcinoma (RCC), either inoperable or after completed percutaneous radiotherapy.

Between January 1992 and December 1997 60 patients with different tumors were treated with perioperative high dose rate brachytherapy with Iridium 192 in afterloading technique (HDR), total dosis 20-30 Gy. Three of the patients had RCC. These patients are presented in detail. In elected patients in whom other forms of treatment are not available or have failed, the method offers an additional therapeutic option and can achieve excellent results.

Aged↗
PubMedDate not supplied

[Spontaneous intestinal perforation in premature infants].

BACKGROUND: Spontaneous intestinal perforations mainly affect preterms within their first two weeks of life. PATHOGENESIS: In contrast to the findings in necrotizing enterocolitis demarcations due to spontaneous perforations are sharply punched out of an otherwise vital bowel section. Pathophysiologic interactions currently are poorly understood. Arterial hypotension and vascular compromises seem to play a crucial role in the development of spontaneous intestinal perforations. CLINICAL ASPECTS: Clinical characteristics are abdominal distension and green-blue discolouration in association with a stable general condition. Intestinal perforations require surgical intervention in terms of primary anastomosis or barrelled stoma, for instance. Spontaneous perforations carry favourable prognosis with a rare chance of relapses.

Diagnosis, Differential↗
PubMedDate not supplied

Low-dose heparinization can be used with DEAE-cellulose hemodialysis membranes.

The ability of DEAE-cellulose (Hemophan) membranes to bind heparin may reduce bioavailable heparin and predispose to dialyzer clotting, thus preventing use of Hemophan with low-dose heparin. To examine this possibility, residual blood volumes were determined following 95 treatments with dialyzers containing Hemophan membranes in 11 patients. No heparin was added to the saline used to prime the dialyzers. The anticoagulant effect of heparin was measured using recalcified activated clotting times (RACT). Two heparin doses, calculated by a pharmacokinetic model to increase baseline RACT by 12.5% and 25%, were used for each patient. The mean heparin loading doses were 10.2 +/- 2.8 and 15.3 +/- 2.2 IU/kg, respectively, and the mean infusion rates were 11.1 +/- 3.2 and 14.7 +/- 3.2 IU/kg/h, respectively. Residual blood volumes were determined by red cell lysis and hemoglobinometry. In 88 treatments, residual blood volume averaged 1.6 +/- 1.5 ml. In the other seven treatments, residual blood volume greater than 10 ml was seen. In five of these cases, clotting appeared to propagate from the arterial drip chamber. Residual blood volume did not correlate with the level of heparin. The data show that low-dose heparin can be used with Hemophan membranes, and suggest that blood tubing design may be an important factor in blood circuit clotting during hemodialysis.

Adult↗
PubMedDate not supplied

[Congenital muscular dystrophy. Report of 8 cases with evidence of central nervous system involvement].

Twelve patients with congenital muscular dystrophy (CMD) diagnosed by clinical and laboratorial criteria were submitted to CT scanning. Eight patients presented diffuse bilateral hypodensity of the white matter with predominance in the frontal lobes. These findings are indicative that CNS involvement in CMD is not confined to the Japanese population. Such involvement strongly suggests that the disease is transmitted by an autosomal recessive polymorphic gene responsible for the involvement of both CNS and skeletal muscle.

Brain Diseases↗
PubMedDate not supplied

[Classification of handicaps in elderly citizens].

As a preliminary result of our research with the ICIDH we propose a classification scheme of disability for older people. The patient classification in a consistent manner is possible applying a questionnaire for assessing functional disability (mobility, self-care, housecare, mental state). The suitability of the questionnaire was evaluated using a sample of non-institutionalized severely dependent elderly. The classification scheme categorizes patients according to the "interval of need" (Isaacs and Neville) for personal assistance. Levels of dependency are specified identifying the housing and support service needs for the elderly in the community. The applications of the classification scheme to both social services planning and case decision-making are discussed. Further investigation is necessary before screening inventories and criteria can be designed.

Activities of Daily Living↗
PubMedDate not supplied

Cystosarcoma phyllodes.

A series of 27 cystosarcoma phyllodes diagnosed in 23 patients is presented. Treatment consisted of wide local excision with a rim of normal tissue for the histologically benign-appearing tumors, and simple mastectomy for the histologically malignant-appearing tumors. Of the three tumors with a malignant appearance, one metastasized distantly and the patient died; the other two patients were apparently cured. Of the 24 benign-appearing tumors, 3 recurred locally and were cured by reexcision. None behaved in a malignant fashion. There was one case of bilateral cystosarcoma phyllodes, and one tumor was associated with carcinoma of the breast. The local recurrence rate of 11% (3 out of 27) and mortality rate of 4% (1 out of 23) appears to justify this therapeutic approach. The precise indications for mastectomy in this disease are still unclear.

Adolescent↗
PubMedDate not supplied

Apheresis without substitution fluid: devices, directions and limitations.

Significant economic and medical drawbacks attend the requirement for infusion of large quantities of exogenous substitution fluid during therapeutic plasma exchange. A variety of physicochemical processes are available for the fractionation of plasma (ultrafiltration, fractional precipitation, adsorption, electrophoresis, selective enzymatic degradation) and we review here their application to 'closed loop' apheresis, a format in which the patient's own plasma is returned after the pathogenic species are removed. The different separation processes vary significantly in their method of action, their specificity, and their status of development. Disposables and hardware for two specific protocols, cascade filtration and cryofiltration, are already commercially available and appropriate for routine clinical use in limited subsets of diseases considered treatable by therapeutic apheresis.

Adsorption↗