Biomedical subjects

R Lange

Publications and source records attributed to R Lange.

At least 289 records · Page 16Linked to original sources

PubMed1992

Ovalbumin blocking improves sensitivity and specificity of immunoglobulin M immunoblotting for serodiagnosis of patients with erythema migrans.

To improve the serodiagnosis of erythema migrans, we evaluated how sensitivity and specificity of immunoblotting are influenced by antigen concentration and blocking conditions. We found that an antigen concentration of 0.5 micrograms per lane in concert with ovalbumin blocking of the nitrocellulose provided the best results. In this case, 81% of the erythema migrans had positive immunoglobulin M tests, whereas only 33% were positive in a flagellum enzyme-linked immunosorbent assay (ELISA) and 28% were positive in a sonicate ELISA.

Antibody Specificity↗

PubMed1992

[Correlation between neurologic disease and Borrelia burgdorferi antibodies in 800 paired serum/cerebrospinal fluid samples].

Paired serum and cerebrospinal fluid (CSF) samples from 800 patients of a neurological clinic were tested for antibodies to Borrelia burgdorferi. A flagellum enzyme-linked immunosorbent assay was used for antibody screening. All serum/CSF pairs with any elevated antibody response were also tested by a Western blot, a method for confirmation. 65 patients (8.1%) had serum IgG antibodies on ELISA screening and 22 of these (2.8%) were confirmed by Western blot. 20 patients (2.5%) had elevated antibody titers in CSF by ELISA and 12 of these (1.5%) reacted to the Western blot. Clinical features of Bannwarth's syndrome (BS) were present in 12 patients (1.5%) and four patients (0.5%) showed other manifestations of Lyme borreliosis. All patients with Bannwarth's syndrome were positive in serum by both methods and 10 had elevated antibody activity in the CSF proven by the two methods. The combination of a sensitive ELISA for screening and a sensitive and specific Western blot for confirmation reduces the number of positive results but is sensitive in detecting active disease.

Antibodies, Bacterial↗

PubMed1992

Gastric tolerance of single dose unbuffered and buffered acetylsalicylic acid: a randomized comparative endoscopic study in 24 volunteers.

A randomized, three-way crossover study by gastroscopic examination in 24 healthy male volunteers was performed to compare the gastric tolerance of a single dose of buffered or unbuffered acetylsalicylic acid. Gastroscopic assessment was made two hours after administration of the buffered (800 mg ASA) or unbuffered (500 mg ASA) tablets taken with 200 ml of water. Mucosal changes were rare and of a minor nature. Only two volunteers in the unbuffered ASA group presented minor changes (erythema and oedema). No pathological changes were observed after the buffered ASA. Subjective adverse reactions, e.g. epigastric complaints, were reported by four volunteers in the unbuffered group and by two in the buffered group. Based on the limited number and the minor extent of visible changes, statistical tests did not appear to be warranted. The results indicate that buffered ASA is better tolerated.

Adult↗

PubMed1992

[Intraoperative evaluation of tricuspid valve annuloplasty with transesophageal echocardiography].

The present study shows a new application of transesophageal echocardiography (TEE) to optimize tricuspid valve annuloplasty. Eighteen patients with tricuspid regurgitation (TR) underwent De Vega tricuspid annuloplasty. After cardiopulmonary bypass the tension on the suture was adjusted until the surgeon could not feel any regurgitant jet by intraatrial palpation; subsequently, the tension was further adjusted on the basis of TEE. The post-pump residual tricuspid regurgitation was assessed by semiquantitative grading of tricuspid regurgitation (0 to 4+), area of regurgitant jet and percentage of right atrial area subtended by jet area. The data obtained by intraatrial palpation were compared with the data obtained by TEE. A significant reduction of residual tricuspid regurgitation was shown by TEE when compared to intraatrial palpation. After a follow-up period of 2 weeks, no significant changes in the grade of TR were observed. The results showed that the use of TEE was able to optimize the De Vega's tricuspid annuloplasty.

Adult↗

PubMed1992

Gastric emptying in childhood inflammatory bowel disease: nutritional and pathologic correlates.

To determine the incidence of gastric emptying abnormalities in children with inflammatory bowel disease, we performed dual liquid/solid-emptying studies on 25 children with ulcerative colitis (UC) and on 45 with Crohn's disease (CD) over a 6-yr period. Nutritional parameters were evaluated initially and at the time of repeat study in those with abnormal emptying after a period of nutritional rehabilitation. All UC patients and 30 of 45 with CD (67%) had normal emptying of both liquid and solid components of the meal. Fifteen children with CD had delayed emptying of the solid liquid. Fourteen of these had preceding weight loss and one had no weight gain for 3 months prior to the study. Twelve complained of upper gastrointestinal symptoms (nausea, early satiety, postprandial epigastric pain, and anorexia), and five had evidence of growth retardation. The group averaged 4.8 abnormal nutritional parameters, compared with an average of 2.2 in those with CD and normal gastric emptying. Twelve of the 15 with abnormal emptying had abnormal gastric and/or duodenal biopsies: 10 were treated with sulfasalazine and prednisone, whereas five were taking only sulfasalazine. Studies repeated 6-15 months later after establishment of weight gain by caloric supplementation showed significant improvements in gastric emptying, nutritional status, and disease activity for the group, despite persistence of upper gastrointestinal disease documented in eight patients who underwent reexamination.

Adolescent↗

PubMed1991

Nanosecond fluorescence of tryptophans in cytochrome P-450scc (CYP11A1): effect of substrate binding.

Fluorescence of eight tryptophan residues in cytochrome P-450scc with bound endogenous cholesterol could be fitted with a two component model: a single exponential and a "top-hat" distribution of lifetimes as the second component. The short-lived component (tau 1 about 700 ps) does not change significantly upon binding of substrate (22R-hydroxycholesterol). The parameters of the long-lived component (central lifetime tau m about 3.4 ns) change upon binding of carbon monoxide and substrate. 22R-hydroxycholesterol binding broadens the distribution of the long-lived component; that is the heterogeneity of the Trp environment is increased when this substrate displaces the endogenous cholesterol.

Adrenal Glands↗

PubMed1991

[Experiences with a modified implantation technique of Port-A-Cath systems as continuous venous access in infants and children].

Since April 1987 we implanted the Port-A-Cath infusion system in 60 children in the age of 2 months to 16 years (median: 4.3 years). We only used the adult system (Pharmacia). By one right side infraclavicular incision the silicon catheter was implanted into the jugular vein and also the port was fixed on the pectoral fascia. We saw one severe complication as a port perforation through the skin. 1.6% was the very low rate of complications which appeared in the median of the port using time of 168.5 days.

Adolescent↗

PubMed1991

Isolation and characterization of a cytochrome P450 of the IIA subfamily from human liver microsomes.

Antibodies raised against cytochrome P450, which is overexpressed in mouse hepatic tumors, (P450tu) crossreact with two human liver microsomal proteins (49 kDa and 52 kDa). We have quantified these proteins in 60 human liver samples and found great interindividual variability in both of them. The concentration of the 49-kDa protein varies up to 144 fold in the various samples and represents typically 10% of the total mincrosomal P450 content. Its immunologically determined concentration correlates well (R = 0.78) with the microsomal coumarin-7-hydroylase (COH) activity. This activity is strongly and completely inhibited by anti-P450tu antibody (IC50 = 0.13 mg IgG/mg microsomal protein). The crossreacting 49-kDa protein shows an unusually high substrate specificity towards coumarin; it presents all human COH and part of 7-ethoxycoumarin O-deethylase (ECOD). Besides these two activities, we did not find any activity with other typical P450 substrates. In primary cultures of human hepatocytes, it is inducible by phenobarbital and dexamethasone, but not by pyrazole and beta-naphthoflavone. We isolated this protein from human liver microsomes and purified it to homogeneity by a combination of aminooctyl-amino-Sepharose chromatography and immunoaffinity chromatography. The protein was identified as a cytochrome P450 of the IIA subfamily. Its N-terminal amino-acid sequence was identical with the first 20 residues deduced from the nucleotide sequence of P450IIA6.

7-Alkoxycoumarin O-Dealkylase↗

PubMed1991

Analyzing contractile responses in demembranized pig papillary muscle fibres: the influence of calcium, resting force, and temperature.

The influence of calcium, resting force and temperature on the contractile behaviour in isolated demembranized ("skinned") pig papillary muscle fibers (n = 36) was analysed. Demembranisation excludes the influence of any membrane related processes on the contractile response as the myofilaments are in direct contact with the bathing medium. Resting force (1 mN-9 mN), temperature (22 degrees C or 32 degrees C) and pCa 7.0-4.3 were varied and the contractile response was analyzed by studying the time constant and the extent of post vibration force recovery (PVFR) of the activated preparations (the vibration method). Additional constant-load experiments and detection of sarcomere-length were carried out. There was an inverse-linear relationship between time constants of post vibration force recovery and maximum shortening velocity as estimated by constant load experiments. Resting force affected the extent of force development but not the time constant of post vibration force recovery and modulated the pCa-force relationship without altering the calcium concentration required for half-maximal activation (calcium sensitivity). In contrast lowering the bath temperature from 32 degrees C to 22 degrees C caused a significant leftward shift of the pCa-force relationship potentially due to changes of the contractile filaments' calcium sensitivity. The effect of temperature on the myocardial contractile system is of special interest as hypothermia is frequently used in cardiac surgery. Analysis of alterations of the contractile proteins' calcium sensitivity during the rewarming period of the patient may provide further insight in the pathophysiology of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗

PubMed1991

Identification of a central regulator of stationary-phase gene expression in Escherichia coli.

During carbon-starvation-induced entry into stationary phase, Escherichia coli cells exhibit a variety of physiological and morphological changes that ensure survival during periods of prolonged starvation. Induction of 30-50 proteins of mostly unknown function has been shown under these conditions. In an attempt to identify C-starvation-regulated genes we isolated and characterized chromosomal C-starvation-induced csi::lacZ fusions using the lambda placMu system. One operon fusion (csi2::lacZ) has been studied in detail. csi2::lacZ was induced during transition from exponential to stationary phase and was negatively regulated by cAMP. It was mapped at 59 min on the E. coli chromosome and conferred a pleiotropic phenotype. As demonstrated by two-dimensional gel electrophoresis, cells carrying csi2::lacZ did not synthesize at least 16 proteins present in an isogenic csi2+ strain. Cells containing csi2::lacZ or csi2::Tn10 did not produce glycogen, did not develop thermotolerance and H2O2 resistance, and did not induce a stationary-phase-specific acidic phosphatase (AppA) as well as another csi fusion (csi5::lacZ). Moreover, they died off much more rapidly than wild-type cells during prolonged starvation. We conclude that csi2::lacZ defines a regulatory gene of central importanc e for stationary phase E. coli cells. These results and the cloning of the wild-type gene corresponding to csi2 demonstrated that the csi2 locus is allelic with the previously identified regulatory genes katF and appR. The katF sequence indicated that its gene product is a novel sigma factor supposed to regulate expression of catalase HPII and exonuclease III (Mulvey and Loewen, 1989). We suggest that this novel sigma subunit of RNA polymerase defined by csi2/katF/appR is a central early regulator of a large starvation/stationary phase regulon in E. coli and propose 'rpoS' ('sigma S') as appropriate designations.

Acid Phosphatase↗

PubMed1991

Performance of dynamic cardiomyoplasty related to the functional state of the heart.

Cardiomyoplasty (CMP) was performed with the left Latissimus dorsi in five beagles (group 1) with intact hearts and seven foxhounds (group 2) in whom the left ventricle was enlarged by 31 +/- 11.9% of cross-sectional area. Ventricular function curves were constructed at filling pressures ranging from 15-40 mmHg (group 2). Myocardial contraction patterns were investigated by epicardial 2-D echocardiography. Skeletal muscle contraction caused a significant increase in aortic pressure, dP/dt, stroke volume, work and performance in all animals. Function curves were shifted upward in a parallel manner. Echocardiography showed an increase of the LV cross-sectional delta area of 14.8% +/- 5.8% (group 1) and of 39.5% +/- 15.1%, and approximation of the edges of the wall defects (group 2). In conclusion, dynamic CMP as applied in this acute model, increased the performance of normal canine hearts and hence, a model of cardiac failure may not be a prerequisite for the investigation of certain technical aspects of CMP. In the failing heart, a parallel upward shift of myocardial function curves suggested increased performance of the heart/skeletal muscle complex over a wide range of filling pressures. However, the descending limb of the function curve with increasing filling pressures was observed despite skeletal muscle contraction. Hence, similar to other assist systems, the residual function of the heart may be of considerable importance in the overall performance of dynamic CMP.

Acute Disease↗

PubMed1991

Growth phase-regulated expression of bolA and morphology of stationary-phase Escherichia coli cells are controlled by the novel sigma factor sigma S.

The novel sigma factor (sigma S) encoded by rpoS (katF) is required for induction of many growth phase-regulated genes and expression of a variety of stationary-phase phenotypes in Escherichia coli. Here we demonstrate that wild-type cells exhibit spherical morphology in stationary phase, whereas rpoS mutant cells remain rod shaped and are generally larger. Size reduction of E. coli cells along the growth curve is a continuous and at least biphasic process, the second phase of which is absent in rpoS-deficient cells and correlates with induction of the morphogene bolA in wild-type cells. Stationary-phase induction of bolA is dependent on sigma S. The "gearbox" a characteristic sequence motif present in the sigma S-dependent growth phase- and growth rate-regulated bolAp1 promoter, is not recognized by sigma S, since stationary-phase induction of the mcbA promoter, which also contains a gearbox, does not require sigma S, and other sigma S-controlled promoters do not contain gearboxes. However, good homology to the potential -35 and -10 consensus sequences for sigma S regulation is found in the bolAp1 promoter.

Bacterial Proteins↗

PubMed1991

Trehalose synthesis genes are controlled by the putative sigma factor encoded by rpoS and are involved in stationary-phase thermotolerance in Escherichia coli.

The rpoS (katF) gene of Escherichia coli encodes a putative sigma factor (sigma S) required for the expression of a variety of stationary phase-induced genes, for the development of stationary-phase stress resistance, and for long-term starvation survival (R. Lange and R. Hengge-Aronis, Mol. Microbiol. 5:49-59, 1991). Here we show that the genes otsA, otsB, treA, and osmB, previously known to be osmotically regulated, are also induced during transition into stationary phase in a sigma S-dependent manner. otsA and otsB, which encode trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase, respectively, are involved in sigma S-dependent stationary-phase thermotolerance. Neither sigma S nor trehalose, however, is required for the development of adaptive thermotolerance in growing cells, which might be controlled by sigma E.

Adaptation, Physiological↗

PubMed1991

Enzyme activities, isoenzyme pattern and alpha-1-adrenergic receptor number in primary cultured hepatocytes.

Changes in the activities of pyruvate kinase, tyrosine aminotransferase and adenylate cyclase as well as in the number of alpha-1-adrenergic receptors of hepatocytes maintained in primary culture were investigated. During the culture in the presence of insulin and dexamethasone the activity of tyrosine aminotransferase (TAT) increased. The increase was suppressed by 12-O-tetradecanoylphorbol-13-acetate (TPA). The basic activity of adenylate cyclase increased; however, a weaker stimulation of the enzyme by glucagon was found. A loss of stimulation of pyruvate kinase by fructose-1,6-bisphosphate may result from phosphorylation of the enzyme. The number of alpha-1-adrenergic receptors decreased during culture, an event not influenced by TPA.

Adenylyl Cyclases↗

PubMed1991

[Vitamin B1 deficiency as cause of a severe lactic acidosis and ileus symptoms].

A 2-year-old boy presented with severe lactic acidosis and ileus symptoms after 3 weeks of parenteral nutrition. Diagnosis of thiamine deficiency was made only when further complications had occurred. This case shows the importance of sufficient substitution of thiamine during parenteral nutrition. In lactic acidosis of unknown etiology thiamine deficiency must be considered.

Acidosis, Lactic↗

PubMed1991

Outcomes of pregnancies among women and partners of men with a history of exposure to methoxsalen photochemotherapy (PUVA) for the treatment of psoriasis.

Because oral methoxsalen and UV-A radiation (PUVA) therapy is mutagenic, concern exists about the potential for teratogenic effects resulting from the use of this therapy at the time of conception and during pregnancy. After 12.8 years of prospective study, we documented the pregnancy outcomes among 1380 patients (892 men and 488 women) who received PUVA treatments. Ninety-four men reported 167 pregnancies in their partners, and 93 women reported 159 pregnancies. For 34% of pregnancies among partners of male patients, the man received PUVA therapy near the time of conception. Nineteen percent of female patients reported exposure to PUVA at the time of conception or during pregnancy. Induced and spontaneous abortions were reported as the outcome of pregnancy more often by female than by male patients (12% vs 30%). Two congenital malformations and two stillbirths occurred, an incidence not significantly different from that expected for the general population. Although the power of our study to detect an increase in the risk of specific defects is limited, our data show no evidence to suggest that PUVA is a potent teratogen. Still, because PUVA is mutagenic, we believe it prudent for patients to avoid PUVA treatment during pregnancy whenever practical.

Abortion, Induced↗

PubMed1991

[Porto-femoro-subclavian bypass and the rapid infusion technique in orthotopic liver transplantation].

Veno-venous bypass during orthotopic liver transplantation is commonly performed as a porto-femoro-axillary bypass. Right-angle positioning of one patient's arm and surgical preparation of the femoral and axillary veins are necessary. In 17 patients and 20 consecutive orthotopic liver transplant procedures the common porto-femoro-axillary veno-venous bypass was substituted by porto-femoro-subclavian bypass with a percutaneous 20 F cannulation set (LAUB catheter, Cook). The 20 F catheter was introduced into the left subclavian vein by Seldinger's technique before the operation and was connected intraoperatively to the outflow tube of the biopump. Surgical preparation of the axillary vein was not performed. In 10 patients a Y-connector was used to connect up the Rapid Infusion System in addition. Postoperatively the catheter was left in place for 2-4 days. Introduction and removal of the catheter were uneventful in all cases. High blood flow through the catheter could be maintained by a low driving pressure of the pump (4000 ml/min; 100 mmHg). No intraoperative complications were observed. Shunt flows remained stable throughout the surgical procedure during the anhepatic stage. There was no bleeding from the puncture site, especially after removal of the catheter, though several patients had a poor coagulatory status in the early postoperative period. Two postoperative complications were observed: air embolism due to disconnection and formation of a thrombus at the catheter tip, which it was possible to remove together with the catheter itself. Installation of an irrigation infusion in the postoperative period and well-tightened connections help avoid such complications as thrombus formation, bleeding or air embolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Electrocardiographic signal-averaging during atrial pacing and effect of cycle length on the terminal QRS in patients with and without inducible ventricular tachycardia.

Electrocardiographic signal-averaging during sinus rhythm (61 to 99 beats/min) and atrial pacing (100 to 171 beats/min) were performed to determine the effect of heart rate on late potentials in 15 patients without (group 1) and 7 patients with (group 2) inducible sustained ventricular tachycardia (VT). In sinus rhythm (79 +/- 12 vs 77 +/- 12 beats/min, difference not significant), the duration of the low-amplitude signal less than 40 microV was longer in group 2 than group 1 (43 +/- 21 vs 26 +/- 8 ms, p = 0.034) and more patients had late potentials (57 vs 7%, p = 0.021), but QRS duration (121 +/- 32 vs 98 +/- 19 ms) and terminal voltage (33 +/- 33 vs 50 +/- 26 ms) were not significantly different. With atrial pacing in group 1 (128 +/- 16 beats/min), 3 patients developed a simultaneous decrease in terminal voltage and an increase in terminal QRS duration consistent with a late potential, but mean total and terminal durations were unchanged. Terminal voltage increased (50 +/- 26 to 59 +/- 40) but not significantly. With atrial pacing in group 2 (119 +/- 12 beats/min) all patients either had a late potential or developed a simultaneous decrease in terminal voltage and an increase in terminal QRS duration (p = 0.001 vs group 1). Root mean square (p = 0.001 vs group 1). Root mean square voltage decreased (33 +/- 23 to 22 +/- 23) and became significantly different from group 1 (p = 0.017). Mean QRS duration, root mean square terminal voltage and low-amplitude terminal QRS duration, however, were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗