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Biomedical subjects

C Lang

Publications and source records attributed to C Lang.

At least 73 records · Page 4Linked to original sources
PubMed1999

High rates of appendicectomy in a developing country: an attempt to contribute to a more rational use of surgical resources.

OBJECTIVE: In view of the high appendicectomy rate in a university teaching hospital in a developing country, we investigated the regional epidemiology of appendicitis. DESIGN: Prospective clinical and pathological study. SETTING: Teaching hospital, Madagascar. SUBJECTS: 165 patients who underwent appendicectomy during a two month period. INTERVENTIONS: Clinical investigation and histopathological examination of removed appendixes. MAIN OUTCOME MEASURES: Appendicitis score, local incidence of appendicectomy, appendicitis, perforation, and negative appendicectomy. RESULTS: There was a high incidence of primary appendicectomy (51.1/10,000 population/year) in relation to the incidence of histologically confirmed appendicitis (7.7/10,000), resulting in a negative appendicectomy rate of 85% (43/10,000). There were considerable sex related differences in the incidence of primary appendicectomy (81/10,000 women/year; 22/10,000 men), appendicectomy for appendicitis (12/10,000 women/year; 4/10,000 men) and non-perforating appendicitis (8/10,000 women/year; 2/10,000 men), but much less in that of perforating appendicitis (4/10,000 women/year; 2/10,000 men). CONCLUSION: There is potential for more economic use of medical resources by reducing the rate of negative appendicectomy. The incidence of non-perforating appendicitis depends on the number of appendicectomies done, which may explain the differences observed in the incidence of appendicitis between industrialised and developing countries.

Appendectomy↗
PubMed1999

Propofol-thiopentone admixture-hypnotic dose, pain on injection and effect on blood pressure.

This study examined some pharmacodynamic characteristics of two admixtures of propofol and thiopentone. Ninety unpremedicated ASA 1 or 2 patients were group-randomized to receive, in a double-blinded manner, one of the following mixtures for induction of anaesthesia: Group P50: propofol 1% 10 ml/thiopentone 2.5% 10 ml; Group P75: propofol 1% 15 ml/thiopentone 2.5% 5 ml; Group P100: propofol 1% 20 ml/lignocaine 1% 4 ml. An additional 30 randomized but unblinded patients from the same patient cohort received thiopentone 2.5% to provide predictive dose data for groups P50 and P75. Haemodynamic data were collected pre- and post-induction. The required induction dose of both mixtures of propofol and thiopentone found an additive rather than a synergistic interaction with no significant difference between predicted and observed dose. Thiopentone resulted in significantly more rapid induction of anaesthesia than propofol/lignocaine or propofol/thiopentone. The addition of thiopentone to propofol was found to be as efficacious as the mixing of lignocaine with propofol in reducing pain on injection. The fall in systolic blood pressure was significantly less in group P50 compared with groups P75 or P100. Admixture of thiopentone with propofol results in an additive hypnotic effect, a reduction in pain of injection (comparable with addition of lignocaine) and a reduced hypotensive response compared to propofol injection alone during induction.

Adolescent↗
PubMed1999

Formation of a carcinogenic aromatic amine from an azo dye by human skin bacteria in vitro.

Azo dyes represent the major class of dyestuffs. They are metabolised to the corresponding amines by liver enzymes and the intestinal microflora following incorporation by both experimental animals and humans. For safety evaluation of the dermal exposure of consumers to azo dyes from wearing coloured textiles, a possible cleavage of azo dyes by the skin microflora should be considered since, in contrast to many dyes, aromatic amines are easily absorbed by the skin. A method for measuring the ability of human skin flora to reduce azo dyes was established. In a standard experiment, 3x10(11) cells of a culture of Staphylococcus aureus were incubated in synthetic sweat (pH 6.8, final volume 20 mL) at 28 degrees C for 24 h with Direct Blue 14 (C.I. 23850, DB 14). The reaction products were extracted and analysed using HPLC. The reduction product o-tolidine (3,3'-dimethylbenzidine, OT) could indeed be detected showing that the strain used was able to metabolise DB 14 to the corresponding aromatic amine. In addition to OT, two further metabolites of DB 14 were detected. Using mass spectrometry they were identified as 3,3'-dimethyl-4-amino-4'-hydroxybiphenyl and 3, 3'-dimethyl-4-aminobiphenyl. The ability to cleave azo dyes seems to be widely distributed among human skin bacteria, as, under these in vitro conditions, bacteria isolated from healthy human skin and human skin bacteria from strain collections also exhibited azo reductase activity. Further studies are in progress in order to include additional azo dyes and coloured textiles. At the moment, the meaning of the results with regard to consumer health cannot be finally assessed.

Benzidines↗
PubMed1999

Molecular characterization and developmentally regulated expression of Xenopus lamina-associated polypeptide 2 (XLAP2).

Lamina-associated polypeptides 2 (LAP2alpha, beta, gamma)/thymopoietins (TPalpha, beta, gamma) are a family of proteins that are generated by alternative splicing from a single gene. These proteins have been primarily characterized in mammals. One member of this protein family, the integral membrane protein LAP2beta/TPbeta, has been localized to the inner nuclear membrane of somatic cells where it binds to chromatin and B-type lamins. By cDNA cloning we have characterized XLAP2, a Xenopus homologue of the mammalian LAP2beta. Using LAP2-specific antibodies, the Mr 68,000 XLAP2 was found to be the only member of the LAP2/TP family expressed in somatic cells and adult tissues. XLAP2 was not detected in oocytes, eggs and in early embryos up to the gastrula stage at the mRNA and protein level demonstrating that it is not synthesized from maternal mRNA. In counterpart oocytes, eggs, and embryos contained one LAP2-related integral membrane proteins of Mr 84,000. Northern blot analysis with the XLAP2 cDNA showed that a single hybridizing mRNA band of 1.8-2.0 kb was present in Xenopus somatic cells whereas two other hybridizing mRNA species of 2.8-3.0 and 0. 9-1.1 kb were present in oocytes, eggs and early embryos. All together, these results indicated that at least three distinct LAP2-related proteins might be expressed in Xenopus. The LAP2/TP protein of Mr 84,000 is present in the early embryos but its amount decreases during embryogenesis concomitant with the increase of XLAP2 in the embryo. Our results are the first description of the developmentally regulated expression of integral nuclear envelope proteins during early embryogenesis.

Amino Acid Sequence↗
PubMed1998

Conformational analysis of ketolide, conformations of RU 004 in solution and bound to bacterial ribosomes.

A new structurally distinct class of 14-membered-ring macrolides is characterized by a keto-function instead of the cladinose sugar, well-known for its fragility even in weakly acidic media. This new class called ketolides is endowed with remarkable antibacterial activity against macrolide-resistant strains. A complete assignment of the 1H and 13C NMR spectra of RU 004 in deuteriochloroform, methanol-d4 and D2O has been made using different two-dimensional (2D) chemical-shift correlation methods. The study of ketolide-ribosome interaction has been investigated using 2D transferred nuclear Overhauser effect spectroscopy (TRNOESY). A comparison of the conformations in solution and bound to ribosomes was made with those of previous macrolides. This study can highlight some of the significant differences between RU 004 and other antibiotics.

Anti-Bacterial Agents↗
PubMed1998

Human transferrin receptor is active and plasma membrane-targeted in yeast.

The human transferrin receptor, a type II plasma membrane protein which mediates iron transport in human cells, was expressed in the yeast Saccharomyces cerevisiae. The transferrin receptor synthesized by yeast cells was posttranslationally modified comparable to the native receptor with respect to glycosylation and dimer formation. The location of the expressed receptor in the yeast plasma membrane indicates that the targeting of this type II membrane protein shares similar mechanisms in yeast and mammalian cells. The yeast-expressed transferrin receptor showed binding activity towards its natural ligand, transferrin in an ELISA binding assay.

Cell Membrane↗
PubMed1998

Overexpression of a cytosolic hydroxymethylglutaryl-CoA reductase leads to squalene accumulation in yeast.

The enzyme 3-hydroxy-3-methylglutaryl-co-enzyme-A (HMG-CoA) reductase is known as the rate limiting enzyme in early sterol biosynthesis in eukaryotic cells. To eliminate this regulation in the yeast Saccharomyces cerevisiae, a truncated HMG1 gene, producing a form of the enzyme that lacks the membrane-binding region (i.e. amino acids 1-552), was constructed and overexpressed in this yeast. The transformed strains accumulated large amounts of the sterol precursor squalene, while the levels of ergosterol and a number of other sterol compounds were only slightly elevated. These findings suggest that HMG-CoA reductase is not the only rate-limiting step in sterol synthesis and its overexpression cannot significantly influence this pathway beyond the sterol precursor squalene.

Cytosol↗
PubMed1998

Hyperemesis gravidarum associated with Helicobacter pylori seropositivity.

OBJECTIVE: To test the hypothesis that infection with Helicobacter pylori is associated with hyperemesis gravidarum. METHODS: From January 1995 to November 1996 we enrolled 105 patients with hyperemesis gravidarum in a prospective study. The Helicobacter serum Immunoglobulin (Ig) G concentrations in these patients were compared with those in asymptomatic gravidas matched for week of gestation. RESULTS: Positive serum IgG concentrations were found in 95 of the 105 hyperemesis patients (90.5%) compared with 60 of 129 controls (46.5%). A chi2 test showed statistical significance (P < .001). The mean (+/-standard deviation) index percentages of the IgG titers were 74.2+/-23.6% in the hyperemesis group and 24.3+/-4.4% in the control group (P < .01, Student t test). CONCLUSION: Infection with H pylori may cause hyperemesis gravidarum.

Adolescent↗
PubMed1998

p53 autoantibodies in patients with urological tumours.

OBJECTIVE: To determine the presence of p53 serum antibodies in patients with clinically well-defined urological cancer using a new enzyme-linked immunosorbent assay (ELISA). PATIENTS AND METHODS: The study included 73 patients with prostatic cancer, 72 with transitional cell carcinoma of the urinary tract, 37 with renal cell cancer and 16 controls with a benign disease, all of whom were tested using the ELISA for p53 autoantibodies. The specific reaction of the ELISA (positive p53 antibody titre) was confirmed by Western Blot analysis. RESULTS: Thirteen patients with cancer and one control patient (7.6% overall) were positive for p53 autoantibodies. The sensitivity of the test was low, whereas the specificity was remarkably high. Surprisingly, 9 of the 13 p53-positive patients died within a median of 3.7 months (range 2-6) and the one positive control patient died of undetected lung cancer. There was no significant correlation of p53 antibody positivity with clinical stage or tumour-specific differences. CONCLUSIONS: The expression of p53 autoantibody seems to be a very late but significant event in urological tumour development, with the worst outcome (tumour-specific death) within a few weeks of developing positivity. In histopathologically heterogeneous tumour entities, p53 autoantibodies might be independent prognostic factors in patients with urological cancers.

Autoantibodies↗
PubMed1998

Influence of the renal endothelin A system on the autoregulation of renal hemodynamics in SHRs and WKY rats.

In this study, we investigated the influence of a short-term blockade of the renal endothelin A system on the autoregulation of total renal blood flow, cortical renal blood flow, and pressure-dependent plasma renin activity in spontaneously hypertensive rats (SHRs) and normotensive controls [Wistar-Kyoto (WKY) rats]. In anesthetized rats, renal blood flow was measured by a transit-time flow probe and cortical blood flow by a laser flow probe. Blood samples were taken for measurement of plasma renin activity. Renal perfusion pressure was reduced in 5-mm Hg steps by means of a servocontrolled electropneumatic device by an inflatable suprarenal cuff. During the experiments, the rats (n = 6, each group) received an intrarenal infusion of either the selective endothelin A-receptor antagonist BQ123 (3 mg/kg/h) or vehicle. We observed an improvement of total and cortical blood flow autoregulation as indicated by a shift of lower limits of autoregulation to lower threshold pressures [103 +/- 2 vs. 132 +/- 4 mm Hg compared with 98 +/- 3 vs. 120 +/- 4 mm Hg (mean +/- SEM); p < 0.01 resp. p < 0.05] in BQ123-treated SHRs, whereas BQ123 had no influence on breakpoints of autoregulation in WKY rats (p > 0.05). Pressure-dependent plasma renin activity in SHRs was not influenced by BQ123. Renal blood flow autoregulation is improved in SHRs after short-term blockade of the renal endothelin A system. This effect is independent of the renin-angiotensin system. The endothelin A system does not seem to play an important role in the autoregulation of renal blood flow in normotensive WKY rats.

Animals↗
PubMed1998

Differential alteration of adenylyl cyclase subtypes I, II, and V/VI in postmortem human brains of heroin addicts.

In animal and culture cell experiments, the upregulation of cAMP-related signal transduction after chronic opioid administration has been hypothesized to be an adaptive change of the molecular mechanism to maintain homeostasis in intracellular signals downstream from opioid receptors. Herein, we have examined the quantitative changes of three adenylyl cyclase (AC) subtypes (I, II, and V/VI) in temporal cortex membranes from brains of heroin addicts and age-matched controls by immunoblotting. The immunoreactivity of AC-I decreased significantly (p < 0.05) in heroin addicts, compared with controls; whereas those of AC-II and AC-V/VI were not changed. The present findings indicate that differential regulation of AC subtypes occurs and that AC-I may play an important role in the signal transduction for opiate-induced tolerance and dependence mechanisms in human brain cortex.

Adenylyl Cyclases↗
PubMed1998

Comparison of hyper- and microgravity on rat muscle, organ weights and selected plasma constituents.

BACKGROUND: Centrifugation has been proposed to be one possible countermeasure for the skeletal muscle, organ, hormonal, and plasma chemistry adaptations associated with chronic unloading (e.g., during spaceflight). HYPOTHESIS: Our hypothesis was that there would be a continuum of physiological and morphological responses from zero gravity to hypergravity. METHODS: Adult male rats were centrifuged continuously at 2G for 14 d and the weights of limb muscles and organs, and the levels of plasma constituents were compared with the same measurements from rats flown on a 14-d spaceflight (Cosmos 2044). RESULTS: Mean body weights of centrifuge rats did not change, whereas age-matched controls grew 21%. There was a sparing of muscle protein in the centrifuge rats; the absolute weights of predominantly slow muscles in the hindlimb were maintained and the relative weights (expressed relative to body weight and as a percent difference from control) of almost all muscles studied were larger than control. In contrast, spaceflight resulted in a decrease in the relative weights of most extensor, but not flexor, hindlimb muscles studied. Relative organ weights, in general, were elevated in centrifuge rats compared with control rats. Relative organ weights in flight rats were similar to control, except for a decrease in testes weight. Plasma thyroxine and testosterone levels were significantly reduced following flight, whereas only thyroxine was decreased after centrifugation. Centrifugation resulted in a decrease in most other plasma chemistry measurements, whereas flight rats showed no change or an elevation in these measures. DISCUSSION: These data indicate that the physiological responses to micro- and hypergravity are often in the opposite direction, suggesting that in general there is a continuum of physiological and morphological effects from microgravity to 1G to hypergravity. These data further suggest that the imposition of hypergravity conditions on animals that are in a microgravity environment may have a beneficial effect in maintaining some physiological systems at or near control levels.

Animals↗
PubMed1998

Membrane thickness and PROM--high-frequency ultrasound measurements.

Premature rupture of the membranes (PROM) is still an unsolved problem in obstetrics. Neither prevention nor diagnosis nor therapy is readily available. The amniotic sac is stabilized mechanically by a dense network of collagenous fibres; in the event of PROM, the collagenous mesh is dissolved and the thickness of the amniotic sac is reduced. In a prospective study involving 32 patients, we measured the thickness of the membranes in vitro by high-frequency ultrasound and by light microscopy of histological sections, between gestational weeks 28 and 32. We compared 18 patients with premature rupture of the amnio-chorionic membrane with 14 patients following induction of labour, with intact membranes at the same gestational age in vitro. We were able to show that the membrane in the PROM group (0.54 +/- 0.9 mm) was markedly thinner with fewer collagenous fibres than in the control group (0.74 +/- 1.01 mm). The application of high-frequency ultrasound in vivo in PROM may become helpful for the prediction of PROM; further studies are therefore desirable.

Amnion↗
PubMed1997

[Outpatient management of chronic pain in Middle Franconia].

UNLABELLED: In Middle Franconia, one of the larger Bavarian administrative division (population 1994: 1,657,101), the number of patients suffering from cancer pain, chronic headache and chronic back pain is not known. Furthermore, there are no data on interdisciplinary organization of outpatient pain management. METHODS: All physicians and psychologists involved in outpatient pain management in Middle Franconia (n=2130) were asked (questionnaires) to estimate the number of patients suffering from cancer pain, chronic (>6 months) headache and chronic (>6 months) back pain treated the last 12 months. RESULTS: 264 (12.4%) responses were analyzed; 107,346 patients had been treated in the last 12 months, 67% by a single specialist and 33% by two or more specialists. The participation of psychotherapists and anesthetists in outpatient management of pain patients was poor; 22,754 (21%) patients were thought to need multidisciplinary analgesia therapy in a pain clinic, which actually does not exist in Middle Franconia. CONCLUSION: The data presented suggest that patients suffering from chronic pain are not optimally managed in Middle Franconia. Regional institutions for multidisciplinary pain treatment have to be established close to where chronic pain patients live.

English Abstract↗
PubMed1997

Comparison between esophageal Wallstent and Ultraflex stents in the treatment of malignant stenoses of the esophagus and cardia.

BACKGROUND AND STUDY AIMS: Several published studies have examined various self-expanding metal esophageal stents for use in the palliative treatment of esophageal or cardiac neoplasia, but few have compared different self-expanding metal stents. The aim of this study was to evaluate non-covered Wallstent and Ultraflex prostheses in the treatment of malignancies in the esophagus and the cardiac region. MATERIALS AND METHODS: In a retrospective study, the effectiveness of non-covered Wallstents (46 patients) and Ultraflex stents (36 patients) was compared in the treatment of malignancies in the esophageal and cardiac regions. RESULTS: Reintervention procedures were necessary in 16 of the 46 Wallstent patients (six patients during an early phase) and in 22 of the 36 Ultraflex patients (13 during an early phase) (overall P = 0.022; early P = 0.018). The major complication in the Wallstent group was tumor ingrowth (12 of 35 complications), while in the Ultraflex group, it was incomplete deployment (18 of 49 complications). Incomplete stent deployment occurred more often in patients treated with Ultraflex (P = 0.01), and food impaction was more often observed in the Wallstent group (P = 0.001). In addition, in patients with Ultraflex stents, more complex reinterventions were necessary than those required with Wallstents (four vs. 13 complex reinterventions, P = 0.0046). Wallstents tended to improve dysphagia better than Ultraflex stents. CONCLUSION: Compared to Ultraflex stents, Wallstents have several significant short-term and long-term advantages in the palliative treatment of malignancy of the esophagus and cardia.

Adult↗
PubMed1997

Influence of the renal endothelin system on the autoregulation of renal blood flow in spontaneously hypertensive rats.

The renal endothelin (ET) system has been claimed to play an important role in the regulation of renal blood flow (RBF) and sodium excretion in primary hypertension. The aim of the present study was to investigate the contribution of the endogenous ET system in the autoregulation of total RBF, cortical blood flow (CBF), pressure-dependent plasma renin activity (PRA) and pressure natriuresis in spontaneously hypertensive rats (SHR) by means of the combined (A/B) ET-receptor antagonist, bosentan. In anesthetized rats, RBF was measured by transit-time flow probes and CBF by laser flow probes. During the experiments, the rats received an intrarenal infusion of either bosentan (1 mg/kg/h) or vehicle. Renal perfusion pressure (RPP) was lowered in pressure steps of 5 mm Hg with a servo-controlled electropneumatic device via an inflatable suprarenal cuff. Bosentan had no effect on resting RPP, CBF, PRA and renal sodium excretion, whereas RBF was lowered by 30% (p < 0.05). Furthermore after bosentan the rats revealed a complete loss of RBF autoregulation. In contrast no changes in autoregulation of CBF, pressure-dependent PRA and pressure natriuresis were observed. Our findings demonstrate a significant impairment in total RBF autoregulatory ability during renal ET-receptor blockade which is not confined to the cortical vessels. These data suggest that the renal ET system plays an important role in the dynamic regulation of renal blood flow in SHR.

Animals↗
PubMed1997

Successful treatment of a high-risk choriocarcinoma in Figo stage IV (WHO score 12).

In the present report, a case of high-risk choriocarcinoma (Figo stage IV, WHO score 12) with persisting vaginal and urethral bleedings is described. In addition to a course of multiagent chemotherapy, arterial embolization of both iliac vessels using Gianturco coils was carried out. This caused a dramatic improvement of the patient's general condition. A subsequently performed laparatomy with extirpation of the uterus and both adnexa finally led to remission.

Adult↗