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Biomedical subjects

R Schmid

Publications and source records attributed to R Schmid.

At least 145 records · Page 8Linked to original sources
PubMed1995

Quantitative measurement of HbA1c by an immunoturbidimetric assay compared to a standard HPLC method.

Determination of hemoglobin A1c (HbA1c) is one of the most important monitoring procedures for long-term control of diabetes mellitus. Several analytical methods have been developed for the measurement of glycohemoglobin (GHb). Those most frequently used are ion-exchange chromatography for HbA1c and affinity chromatography for total GHb. In this study, a new turbidimetric immunoassay for HbA1c (Boehringer Mannheim, Germany) was evaluated that was performed on a Hitachi 911 clinical chemistry analyzer (Boehringer Mannheim). Good linearity in the range of 5% to 15% HbA1c, within-run and between-run coefficients of variation ranging from 2.4% to 5.9% were obtained. Results of 179 diabetic and nondiabetic patients showed good correlation to those of a routine HPLC method (r = 0.96). In addition, HbA2, HbS, and HbF in samples from nondiabetic patients were not detected by the immunoturbimetric assay and the "labile" HbA1c fraction (Schiff base) did not interfere with the new test.

Chromatography, High Pressure Liquid↗
PubMed1995

Key metabolite kinetics in human skeletal muscle during ischaemia and reperfusion: measurement by microdialysis.

The tissue kinetics of key metabolites of ischaemic and postischaemic tissue damage were studied in the intercellular space of human skeletal muscle by microdialysis. In vivo microdialysis calibration experiments (n = 5) yielded the basal intercellular concentration of glucose in human skeletal muscle (3.6 +/- 0.6 mM; mean +/- SD). The corresponding mean plasma glucose concentration was 4.3 +/- 0.2 mM which was significantly higher. The time vs. concentration profiles of intercellular glucose (n = 7), lactate (n = 5), TxB2 (n = 6) and urea (n = 8) were characterized during a 20 min period of leg constriction. TxB2 increased exclusively during reperfusion in comparison to baseline (n = 6). Administration of 500 mg acetylsalicylic acid, 5-10 min after onset of ischaemia blunted TxB2-response to reperfusion (n = 4). It is concluded that intercellular muscle glucose concentration is less than that in plasma. Glucose uptake in skeletal muscle is rapid even under ischaemic conditions. Synthesis and release of TxB2 is not evident during ischaemia. TxB2 mediated reperfusion injury might be reduced by acetylsalicylic acid, even if administered after onset of ischaemia.

Adult↗
PubMed1995

A gene at 333 degrees on the Bacillus subtilis chromosome encodes the newly identified sigma B-dependent general stress protein GspA.

In Bacillus subtilis, general stress proteins (Gsps) are induced in response to different stresses (heat, salt, or ethanol) or after nutrient starvation. The majority of the genes for the Gsps are organized in a very large stationary-phase or stress regulon which is controlled by alternative sigma factor sigma B. The most striking spots on Coomassie-stained two-dimensional gels belong to GsiB and GspA, which are synthesized at extremely high levels in response to different stresses. Therefore, we determined the N-terminal protein sequence of GspA, which exhibited total identity to a hypothetical 33.5-kDa protein of B. subtilis encoded by open reading frame 2 (ipa-12d) in the sacY-tyrS1 intergenic region. The GspA-encoding gene gspA and the upstream and downstream regions were cloned with the aid of the PCR technique. By primer extension experiments, one sigma B-dependent promoter immediately upstream of the coding region was identified. A putative factor-independent terminator closely followed the coding region. By Northern (RNA) blot analysis, a 0.95-kb transcript was detected which indicates a monocistronic transcriptional unit. The gspA mRNA was strongly induced by different stimuli like heat or salt stress and starvation for glucose. Analysis of RNA isolated from a sigma B deletion mutant revealed that the transcription of gspA is sigma B dependent. Insertional inactivation of the B. subtilis chromosomal gspA gene confirmed that the gspA gene is not essential for either vegetative growth or growth under the influence of different stresses. In gspA mutant cells, the level of flagellin was increased severalfold over that in wild-type cells.

Amino Acid Sequence↗
PubMed1995

Laparoscopic treatment of biliary and gastric outlet obstruction.

To avoid laparotomy in patients with biliary or gastric outlet obstruction in inoperable carcinoma of the pancreas, we evaluated the feasibility of double-bypass operation in 20 pigs. In model A (n = 10), biliary bypass was a Roux-en-Y loop for cholecystojejunostomy after choledochal clip occlusion. In model B (n = 10) an additional Roux-en-Y loop was attached to the stomach after transection of the duodenum. Model A showed functioning biliary bypass with patent and leak-free anastomoses at necropsy on day 28. In model B, four pigs were sacrificed earlier, but nine had normal functioning double bypass (two intussusceptions of the ileum, one bleeding ulcer at the gastroenterostomy, one necrotic Roux-en-Y-loop). Based on the presented bypass function, we are encouraged to perform laparoscopic biliary and gastroenteral bypass in humans to treat malignant jaundice and gastric outlet obstruction.

Anastomosis, Roux-en-Y↗
PubMed1995

[Secondary traumatic diaphragmatic hernia with incarceration--a diagnostic problem].

In this paper we discuss the case of a 64-year-old patient suffering from a traumatic rupture of the diaphragm with delayed manifestation three years after the trauma. The subsequent diagnostic errors gave rise to a discussion of the value of the physical examination, imaging methods and invasive diagnostic methods, particularly laparoscopy and thoracoscopy in the acute and delayed diagnosis of diaphragmatic injuries.

Arrhythmias, Cardiac↗
PubMed1994

Comparison of Seven Commonly Used Agents for Prophylaxis of Seasickness.

The objective of the study was to compare the efficacy and tolerability of seven drugs frequently used for the prevention of seasickness: the drugs were namely cinnarizine, cinnarizine with domperidone, cyclizine, dimenhydrinate with caffeine, ginger root, meclozine with caffeine, and scopolamine. The design was a randomized, double-blind study with two arms. On ethical grounds, a placebo group was not included as in a previous study, in the same setting, 80% of the passengers not receiving prophylactic drugs were seasick. The setting was in Andenes (Norway) during a time period from July to September 1992. Subjects were 1741 tourist volunteers who were joining a whale safari. The main outcome measures were vomiting, malaise (modified Graybiel criteria), and subjective reports of adverse events. Follow up was possible in 1489 volunteers (85.5%). In each active treatment group, 4.1-10.2% experienced vomiting and 16.4-23.5% experienced malaise (not significant). Equally, there was no significant difference in the incidence and characteristics of adverse events reported in the various medication groups. Scopolamine Transdermal Therapeutic System (TTS) users exhibited slightly more visual problems and the agent tended to be less effective. Six of the seven medications may be recommended for prevention of seasickness; scopolamine TTS seems the least attractive.

Journal Article↗
PubMed1994

[Experimental laparoscopic bypass of bile duct and duodenal obstruction].

UNLABELLED: In order to avoid laparotomy in patients with biliary and/or gastric outlet obstruction due to inoperable carcinoma of the pancreas, the feasibility of minimal invasive double bypass operation was evaluated in 20 pigs. In model A (n = 10) biliary bypass was performed using a Roux-en-Y loop for cholecystojejunostomy after previous choledochal clip occlusion. In mod-el B (n = 10) an additional Roux-en-Y loop was placed to the stomach after transection and closure of the duodenum. RESULTS: Model A showed functioning biliary bypass with patent and leakfree anastomoses at necropsy at day 28. In model B nine of ten had a normal functioning double bypass. One pig was sacrificed at day 6 due to necrotic Roux-en-Y loop. CONCLUSIONS: Laparoscopic biliary and gastroenteral bypass is feasible and safe. Laparoscopic Roux-en-Y loop technique considerably widens the spectrum of minimal invasive visceral surgery.

Anastomosis, Roux-en-Y↗
PubMed1994

Nucleotide-induced conformational changes of MalK, a bacterial ATP binding cassette transporter protein.

Nucleotide-induced structural rearrangements of MalK, the ATP-hydrolyzing component of the ATP binding cassette transporter for maltose from Salmonella typhimurium were investigated by means of analysis of intrinsic tryptophan fluorescence and limited proteolysis. ATP was found to decrease the tryptophan fluorescence of purified MalK by 37 +/- 1%. ADP or adenosine 5'-O-(3-(thio)triphosphate) (ATP gamma S) caused similar quenching while AMP was rather ineffective. Mg2+ ions were not required. Exposure of MalK to increasing concentrations of trypsin and subsequent analysis by SDS-polyacrylamide gel electrophoresis and immunoblotting revealed the formation of three major transiently stable peptide fragments of 24 (T2), 23 (T3), and 20 kDa (T4), respectively. In addition, a minor rapidly degraded fragment of 33 kDa (T1) was observed. However, in the presence of MgATP, fragment T1 as well as a substantial fraction of native MalK were strongly protected against proteolytic attack. Similar protection against the protease was observed in the presence of MgGTP or, to a lesser extent, MgCTP. In contrast, MgADP, ATP in the presence of EDTA, CaATP or nonhydrolyzable nucleotides such as MgATP gamma S or MgAMP-PNP (beta, gamma-imidoadenosine-5'-triphosphate) failed to significantly affect the susceptibility of MalK to the protease. MgATP similarly affected the tryptic digestion pattern of a mutant protein (MalKK42R) that exhibits only a much reduced ATPase activity but has retained the capability to bind nucleotides. N-terminal protein sequence analysis of the peptides revealed cleavage by trypsin at Arg66 (T1), Arg146 (T2), Arg153 (T3), and Arg185 (T4), respectively. These results indicate that (i) nucleotide binding to MalK is accompanied by a global conformational change of the protein; (ii) a very specific interaction occurs with substrates of the MalK-ATPase, resulting in structural changes that involve the helical domain from Arg66 to Arg146; and (iii) the C-terminal half of MalK is rather resistant to proteolysis.

ATP-Binding Cassette Transporters↗
PubMed1994

[Effect of conjugated PRP vaccines on the incidence of invasive diseases caused by Haemophilus influenzae Type B in childhood].

Prior to the introduction of conjugate vaccines, Haemophilus influenzae type b (Hib) was the leading cause of severe invasive infections in young children, in Switzerland as in other countries. From 1976 to 1990, 150 children were treated for Hib meningitis at the Children's Hospital of Lucerne, corresponding to an annual incidence of 9.2 cases per 100,000 children aged under 15 years. In the same time period, the case fatality rate for meningitis was 4%. 87.3% of the meningitis cases occurred among children aged under 5 years. For this age group an annual incidence of 26.4 cases per 100,000 children was calculated. From 1979 to 1990, 141 children were hospitalized for epiglottitis, corresponding to an annual incidence of 10.9 cases per 100,000 children aged under 15. The introduction of conjugated vaccines resulted in a significant reduction in the frequency of invasive Hib disease. From 1991 to 1992, 9 cases each of meningitis and epiglottitis were observed. In 1993, only one case of meningitis and 2 cases of epiglottitis were seen. For children under 15 years these 21 cases represent annual incidences of 3.2 cases of meningitis and 3.6 cases of epiglottitis per 100,000 children. 2 of 10 meningitis cases occurred in twice vaccinated children under 2 years of age with no signs of immunodeficiency, and another case was seen in a 5-month-old infant vaccinated with only one dose. Assuming a vaccination coverage of 70% among children under 5 during the years 1991 and 1992, the calculated efficacy is 80 to 85% for the vaccine PRP-D in this predominantly affected age group during the period when only this vaccine was available.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Hemofiltration during cardiopulmonary bypass: quality assessment of hemoconcentrated blood.

UNLABELLED: Hemofiltration is often used during cardiopulmonary bypass (CPB) for water removal. In a prospective random study 11 patients undergoing elective coronary artery surgery with hemofiltration during CPB were observed and compared to 11 patients without filtration. The quantitative and qualitative aspects of blood before and after filtration while still on CPB and until the first postoperative day were assessed. Intra- and postoperative volume requirements, standard hematology and chemistry, as well as hemolysis, complement activation, and coagulation factors were analysed at nine sequential points in time. RESULTS: There were no significant differences in pre- and postoperative patient data between the two groups except that the majority of patients in the study group (55%) were anticoagulated and required a significantly longer CPB time with higher doses of protamine and had higher postoperative drainage (2.9 vs. 1.4 L). Intra- and postoperative hemoglobin concentrations, transfusion and volume requirements were similar in both groups. 927 ml of plasma water were filtered during CPB within 4 min 20 s without hemodynamic changes or electrolyte imbalance. Hemoglobin and protein concentrations increased significantly during hemofiltration (Hb increases 3.6 g/dl). Hemolysis and activated complement fractions were elevated during CPB but showed no further increase during filtration; in contrast C4a, C5a, and prothrombin F1 + 2 increased significantly after cessation of CPB. In conclusion, hemofiltration during CPB is a safe and efficient method for water removal and for concentration of red blood cells and proteins without adverse effects on the patient's hemodynamics, blood quality, and volume requirements. More especially, no negative influence of hemofiltration could be determined with regard to activation of the coagulation and complement system.

Blood Cell Count↗
PubMed1994

Analysis of the induction of general stress proteins of Bacillus subtilis.

In Bacillus subtilis stress proteins are induced in response to different environmental conditions such as heat shock, salt stress, glucose and oxygen limitation or oxidative stress. These stress proteins have been previously grouped into general stress proteins (Gsps) and heat-specific stress proteins (Hsps). In this investigation the N-terminal sequences of 13 stress proteins of B. subtilis were determined. The quantification of the mRNA and the analysis of the protein synthesis pattern support the initial hypothesis that the chaperones DnaK and GroEL are Hsps in B. subtilis. In contrast, the recently described proteins GsiB, Ctc and RsbW belong to a class of Gsps that are induced by various stresses including heat shock. The main part of the Gsps described in this study failed to be induced in the sigB deletion mutant ML6 in response to heat shock. However, all the five Hsps were induced in this mutant in response to heat shock. These data indicate that SigB plays a crucial role in the induction of general stress genes, but is dispensable for the induction of Hsps.

Amino Acid Sequence↗
PubMed1994

Maltose transport in Aeromonas hydrophila: purification, biochemical characterization and partial protein sequence analysis of a periplasmic maltose-binding protein.

A clinical isolate of Aeromonas hydrophila was demonstrated to transport [14C]maltose with similar kinetics to enteric bacteria (Km: 0.3 microM; Vmax: 22 nmol min-1 per 10(9) cells). The uptake of [14C]maltose was completely inhibited in the presence of unlabelled maltose or maltodextrins, whereas other mono- and disaccharides, such as glucose, galactose, sucrose, lactose or melibiose, had no effect. A protein with an apparent molecular mass of 39 kDa (maltose-binding protein; MBP) was identified in osmotic-shock fluid of maltose-grown cells by SDS-gel electrophoresis, and was purified to homogeneity by either amylose affinity chromatography or ion-exchange chromatography. Equilibrium dialysis experiments revealed the ability of the purified protein to bind [14C]maltose with high affinity (KD = 1.6 microM). Unlabelled maltose and maltodextrins competed for the binding site. In a reconstitution experiment, A. hydrophila MBP poorly restored the transport activity of a binding-protein-deficient Escherichia coli (delta malE) mutant. N-terminal sequence analyses of the purified native protein and of peptides generated by cleavage with CNBr and subsequently separated by HPLC revealed about 56% identical amino acid residues, as compared to enterobacterial MBPs. We conclude that maltose is transported into A. hydrophila via a binding-protein-dependent transport system.

ATP-Binding Cassette Transporters↗
PubMed1994

Demonstration and minimization of serum interference in flow cytometric two-site immunoassays.

The ability of serum factors to cross-link labeled mouse monoclonal antibody (mAb) of irrelevant specificity (mAb FN61, subclass IgG1) to different particle types coated with sheep IgG, bovine gamma-globulin, or mAb FN61 was measured simultaneously by flow cytometry. Significant interference with mAb FN61-coated particles was detected in 53 of 101 sera. Of the 30 sera showing the most pronounced interference, 23 were characterized by an even stronger cross-linking to particles coated with bovine gamma-globulin. These were designated type 1 sera. Seven sera, designated type 2, displayed a dominant interference with the mAb FN61-coated particles. The interference reaction in the two serum types was characterized by different kinetics, dependence on particle concentration, and response to blocking agents. The interference was minimized by addition of 500 micrograms of bovine gamma-globulin and 50 micrograms of mAb HH1 (IgG1) of irrelevant specificity per 10 microL of serum sample in a final assay volume of 100 microL.

Antibodies, Monoclonal↗
PubMed1994

[Laparoscopic Y-Roux anastomosis].

In order to circumvent laparotomy in patients with biliary obstruction due to inoperable carcinoma of the pancreatic head, we evaluated the feasibility of a bypass operation using minimal invasive measures. A technique of laparoscopic cholecystojejunostomy was developed in adult pigs with a previous clip occlusion of the distal common bile duct to imitate choledochal obstruction. Complete biliary bypass was restored with a cholecystojejunostomy via a Roux-en-Y loop using two circular staplers (21, 25 or 29 mm diameter), introduced through a 33-mm-diameter trocar, to perform the proximal and distal anastomoses. 12 pigs operated in this way, recovered easily with normal weight gain and without technical complications. Contrast radiography of the biliary bypass at autopsy on day 28 demonstrated patent and leak-free anastomoses and functional bypass. We conclude that laparoscopic cholecystojejunostomy with Roux-en-Y loop is a feasible technique resulting in an uncomplicated postoperative course and a biliary bypass with optimal function. Endoscopic application of circular staplers to perform laparoscopic entero-biliary and entero-enteral anastomosis is practical and safe.

Anastomosis, Roux-en-Y↗
PubMed1994

[Technique of laparoscopic descendo-rectostomy for reconstruction of intestinal continuity after Hartmann operation].

Reestablishing bowel continuity subsequent to sigma resection with terminal descendostomy and blind closure of the rectum (Hartmann procedure) by a descendo-rectostomy (DR) is well suited for a laparoscopic approach. One part of the operation is performed extracorporally, and with the laparoscopic operation there is no need to consider radical tumor surgery or staging rules. We demonstrate our techniques for laparoscopic DR. - Operational steps. - A. conventionally: complete dissection of the descendo-stoma, insertion of a 29 or 31 mm circular stapler head secured by a purse string suture and repositioning of the colon into the abdomen; blunt dissection of reachable intra-abdominal adhesions with a finger, and placement of a 10-mm umbilical trocar using palpation; air tight closure of the abdominal wall at the original stoma site. B. laparoscopically: upon creation of a CO2 pneumoperitoneum, placement of two additional 10 mm trocars; adhesiolysis of the pelvis; preparation of the blind rectal stump; transanal insertion of the circular stapler and perforation of the rectal stump; bringing down the proximal colon into the pelvis (possible need to mobilise the splenic flexure); reconnecting the stapler head with the instrument and firing the stapled anastomosis. - The postoperative period was uneventful. Using a laparascopic approach for a DR following Hartmann's procedure is an attractive and viable method to reestablish bowel continuity.

Anastomosis, Surgical↗
PubMed1993

[Comparison of conventional versus 24-hour blood pressure measurement. How often do variations in diagnostic/therapeutic evaluation occur?].

QUESTION: The question as to whether and to what extent 24-hour blood pressure measurement (Holter monitoring) is capable of improving the diagnosis and treatment of arterial hypertension was investigated. METHODS: For this purpose, 50 patients with the diagnosis--based on random blood pressure measurement--of, or receiving treatment for, hypertension were referred to our hospital by general practitioners. In 26 patients, the diagnosis hypertension, and in 24 patients the "well-controlled hypertension" were checked with the aid of 24-hour ambulatory monitoring. RESULTS: Of the patients referred with the diagnosis hypertension, 27% were shown by 24-hour blood pressure measurement not to be suffering from hypertension. The treatment of the 24 patients considered to be "well-controlled hypertensives" was validated by 24-hour blood pressure measurement in only 13 cases.

Adult↗