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Biomedical subjects

C Lang

Publications and source records attributed to C Lang.

At least 37 records · Page 2Linked to original sources
PubMed2002

[Plasma cholinesterase variations as a result of prolonged neuromuscular blockade. Review and problems encountered in two cases of prolonged neuromuscular blockade after muscle relaxation with succinylcholine as compared to mivacurium].

Succinylcholine and mivacurium are degraded more slowly in patients with a qualitatively or quantitatively reduced plasma cholinesterase and are therefore known for inducing a prolonged postoperative apnea. Perioperative laboratory screening even including plasma cholinesterase activity testing will not prevent this due to a possible aberration only in the qualitative cholinesterase activity. This is illustrated by introducing two cases reports of prolonged apnea after administration of mivacurium or succinylcholine. The pathophysiology of plasma cholinesterase is reviewed including genetically determined variants and the degradation pathways of mivacurium and succinylcholine. Only extensive laboratory chemical tests are sufficient to prevent this possible complication. Due to the rare incidence there is no evidence for recommending these laboratory investigations in all patients. Once prolonged apnea occurs following the administration of mivacurium or succinylcholine the best choice is ongoing ventilation combined with a sufficient sedation.

Apnea↗
PubMed2002

[Placental passage of anesthetics and adjuvants].

In obstetric anaesthesia almost all anaesthetic agents are capable of traversing the fetomaternal blood barrier. They all carry potential side-effects putting the unborn or newborn child at risk. Of major relevance is their potential for embryotoxicity, teratogenicity, postpartal cardiorespiratory or neuromuscular depression and the disturbance of thermoregulation. This can possibly lead to fetal malformation, asphyxia or floppy infant syndrome. Furthermore compromisation of uterine blood flow or contractility of the mature uterus plays an important role for the incidence of intrauterine asphyxia and premature labour or birth. Considering the physiological and pathophysiological alterations during pregnancy regarding all organ systems, the overall goal is to find an ideal choice of anaesthetic drugs and techniques in order to minimise an increased anaesthetic risk during pregnancy.

Adjuvants, Anesthesia↗
PubMed2002

[First findings about the nasal airflow in noses with septal perforation].

BACKGROUND: A nasal septum perforation often leads to considerable complaints like nasal obstruction, crusting, epistaxis or whistling. Up to now there is no certain knowledge about the airflow pattern in noses with septal perforations. METHOD: We performed fluid dynamic experiments on functional nasal models (so-called modified Mink boxes). We investigated the flow pattern in models with septal perforations, different in size and location and in combination with and without septal deviations. RESULTS AND CONCLUSIONS: We have found no essential influence of the location of perforation on the airflow pattern. With increasing size of perforation the streamlines bump toward the posterior border of the perforation, causing turbulence. The whistling during inspiration is based on the principle of a lip whistle. The required flow velocity for vibration of the air depends on the dimension of the perforation. For large perforations it is impossible to get the required high flow velocity to cause a whistle.

Diagnosis, Differential↗
PubMed2002

[Fibrolipoma of the larynx].

Benign mesenchymal tumors of the upper aerodigestive tract are very rare. In this localisation some tumors cause life-threatening upper airway obstruction. We report on a 42-year old man who complained dysphagia and globus sensation. The physical examination revealed a smooth tumor of the left aryepiglottic fold. A magnet resonance imaging (MRI) leaded to the suspicion of a laryngocele with extension in the left aryepiglottic fold. The therapeutical procedure included the microlaryngoscopical extirpation of the tumor with laser surgery. The histology showed a fibrolipoma of the larynx. Because of frequent recurrences even after an extended period of time long term follow-up is necessary.

Adult↗
PubMed2002

Clear cell chondrosarcoma of the larynx: a case report of a rare histologic variant in an uncommon localization.

The authors describe a clear cell chondrosarcoma of the larynx. The clear cell type is a rare variant of chondrosarcoma that only twice has been reported in this localization. The light-microscopic diagnosis of the actual case was confirmed by immunohistochemical results, in particular by positive staining for S-100 protein and collagen type II, and ultrastructural findings. Loss of heterozygosity analysis demonstrated allelic loss at 9p22 and 18q21, but neither in the region of the Rb gene on chromosome 13q nor at the p53 locus on chromosome 17p where allelic loss has already been reported in chondrosarcomas. Furthermore, our molecular genetic investigations revealed a methylation of the cell cycle control gene p16, which is localized on chromosome 9p. This characteristic has been recorded previously only in high-grade chondrosarcomas. Mutations in the exons of p16, alterations of the putative tumor suppressor gene MMAC1/PTEN on chromosome 10q, or an amplification of the cyclin D1 gene (CCND1) on 11q13, which were found to be changed in other studies of chondrosarcomas, could not be demonstrated here.

Chondrosarcoma↗
PubMed2001

Two distinct effects on neurotransmission in a temperature-sensitive SNAP-25 mutant.

Vesicle fusion in eukaryotic cells is mediated by SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors). In neurons, the t-SNARE SNAP-25 is essential for synaptic vesicle fusion but its exact role in this process is unknown. We have isolated a SNAP-25 temperature-sensitive paralytic mutant in Drosophila, SNAP-25(ts). The mutation causes a Gly50 to Glu change in SNAP-25's first amphipathic helix. A similar mutation in the yeast homologue SEC9 also results in temperature sensitivity, implying a conserved role for this domain in secretion. In vitro-generated 70 kDa SNARE complexes containing SNAP-25(ts) are thermally stable but the mutant SNARE multimers (of approximately 120 kDa) rapidly dissociate at 37 degrees C. The SNAP-25(ts) mutant has two effects on neurotransmitter release depending upon temperature. At 22 degrees C, evoked release of neurotransmitter in SNAP-25(ts) larvae is greatly increased, and at 37 degrees C, the release of neurotransmitter is reduced as compared with controls. Our data suggest that at 22 degrees C the mutation causes the SNARE complex to be more fusion competent but, at 37 degrees C the same mutation leads to SNARE multimer instability and fusion incompetence.

Amino Acid Sequence↗
PubMed2001

Visualization of neuropeptide expression, transport, and exocytosis in Drosophila melanogaster.

Neuropeptides affect an extremely diverse set of physiological processes. Neuropeptides are often coreleased with neurotransmitters but, unlike neurotransmitters, the neuropeptide target cells may be distant from the site(s) of secretion. Thus, it is often difficult to measure the amount of neuropeptide release in vivo by electrophysiological methods. Here we establish an in vivo system for studying the developmental expression, processing, transport, and release of neuropeptides. A GFP-tagged atrial natriuretic factor fusion (preproANF-EMD) was expressed in the Drosophila nervous system with the panneural promoter, elav. During embryonic development, proANF-EMD was first seen to accumulate in synaptic regions of the CNS in stage 17 embryos. By the third instar larval stage, highly fluorescent neurons were evident throughout the CNS. In the adult, fluorescence was pronounced in the mushroom bodies, antennal lobe, and the central complex. At the larval neuromuscular junction, proANF-EMD was concentrated in nerve terminals. We compared the release of proANF-EMD from synaptic boutons of NMJ 6/7, which contain almost exclusively glutamate-containing clear vesicles, to those of NMJ 12, which include the peptidergic type III boutons. Upon depolarization, approximately 60% of the tagged neuropeptide was released from NMJs of both muscles in 15 min, as assayed by decreased fluorescence. Although the elav promoter was equally active in the motor neurons that innervate both NMJs 6/7 and 12, NMJ 12 contained 46-fold more neuropeptide and released much more proANF-EMD during stimulation than did NMJ 6/7. Our results suggest that peptidergic neurons have an enhanced ability to accumulate and/or release neuropeptides as compared to neurons that primarily release classical neurotransmitters.

Animals↗
PubMed2001

[Exclusion of coronary calcium with electron beam tomography: an effective filter before invasive diagnosis in symptomatic patients?].

Electron beam computed tomography (EBCT) is the most sensitive and accurate method of measuring coronary calcium which indicates coronary atherosclerosis. We performed a prospective study in 1764 symptomatic patients who were referred to our hospital for coronary angiography because of suspected coronary artery disease. In all of these patients cardiac catheterization and coronary calcium scanning was performed within 3.2 +/- 4 days. 454/1225 men (37.0%) and 165/539 women (30.6%) had significant coronary stenoses > or = 75%. Only two men (0.4%) and no single woman (0.0%) with stenoses > or = 75% and only 3/323 patients (0.9%) with moderate stenoses (50-75%) did not exhibit coronary calcium. Coronary angiography excluded stenoses in 822 patients. Of these patients 261 (29.4%) did not reveal coronary calcium. In younger patients (< 60 years) without stenosis exclusion of coronary calcium was a frequent finding: 31% of men and 55.8% of women were free of coronary calcium. Thus, exclusion of coronary calcium with electron beam tomography defines a substantial subgroup of patients who have an extremely low risk of significant coronary stenosis despite suspected coronary artery disease in history and non-invasive testing. Determination of coronary calcium might, therefore, be an effective filter before invasive angiography in selected groups of symptomatic patients.

Adult↗
PubMed2001

Neuroleptic malignant syndrome in pregnancy.

BACKGROUND: Neuroleptic malignant syndrome can be a serious neurologic complication of drug therapy during pregnancy. CASE: A young woman was admitted to the intensive care unit with worsening varicella pneumonia. After being given haldol for agitation, she developed fever, increasing agitation, rigidity, tachycardia, and tremors; she was diagnosed as having neuroleptic malignant syndrome. She was treated successfully with bromocriptine and dantrolene. CONCLUSION: Despite the common use of antipsychotic medications, neuroleptic malignant syndrome is seen infrequently during pregnancy. The diagnosis can be difficult to make, but if suspected, it can be treated successfully.

Antipsychotic Agents↗
PubMed2001

Correlation of coronary calcification and angiographically documented stenoses in patients with suspected coronary artery disease: results of 1,764 patients.

OBJECTIVES: This study correlated the electron beam computed tomographic (EBCT) calcium scores with the results of coronary angiography in symptomatic patients in order to assess its value to predict or exclude significant coronary artery disease (CAD). BACKGROUND: Electron beam computed tomography is a sensitive method to detect coronary calcium. However, it is unclear whether it may play a role as a filter before invasive procedures in symptomatic patients. METHODS: A total of 1,764 patients (1,225 men and 539 women) with suspected CAD from a single center were included in our study. All patients underwent calcium screening with EBCT (C150XP Imatron) and conventional coronary angiography. RESULTS: Fifty-six percent of men and 47% of women revealed significant coronary stenoses (> or =50%). Total exclusion of coronary calcium (14% of the study group) was associated with an extremely low probability of stenosis (<1%). With calcium scores > or =20th, > or =100th or > or =75th percentile of age groups, the sensitivity to detect stenoses decreased to 97%, 93% and 81%, respectively, in men and to 98%, 82% and 76%, respectively, in women. At the same time, the specificity increased up to 77% in men and women. There was a significant difference in coronary calcium between men and women in all age groups; however, receiver-operating characteristic curves indicated that the test can be performed with equal accuracy in all of these subgroups. CONCLUSIONS: Calcium screening with EBCT is a highly sensitive and moderately specific test to predict stenotic disease. Exclusion of coronary calcium defines a substantial subgroup of patients, albeit symptomatic, with a very low probability of significant stenoses.

Adult↗
PubMed2001

Sudden death due to pituitary apoplexy.

A case of sudden, unexpected death due to hemorrhage into a large, previously undiagnosed pituitary adenoma (pituitary apoplexy) in a 41-year-old man is presented. Pituitary adenomas are frequent intracranial tumors with usually benign prognosis. Acute hemorrhage into the tumor is a severe and potentially fatal complication, if not diagnosed and treated early, and occurs in up to 10% of cases. Sudden tumor enlargement due to the hemorrhage with compression of vessels and neural tissue at the skull base may result in coma and death without preceding symptoms leading to forensic investigations as demonstrated by this case report.

Journal Article↗
PubMed2001

On the analysis of spatial binary images.

This paper deals with the analysis of spatial images taken from microscopically heterogeneous but macroscopically homogeneous microstructures. A new method is presented, which is strictly based on integral-geometric formulae such as Crofton's intersection formulae and Hadwiger's recursive definition of the Euler number. By means of this approach the quermassdensities can be expressed as the inner products of two vectors where the first vector carries the 'integrated local knowledge' about the microstructure and the second vector depends on the lateral resolution of the image as well as the quadrature rules used in the discretization of the integral-geometric formulae. As an example of application we consider the analysis of spatial microtomographic images obtained from natural sandstones.

Journal Article↗
PubMed2001

[Interesting case no. 44. Osteoma].

We report on a 30-year-old man who was treated in the outpatient clinic for bifrontal headache for four weeks. Computed tomography showed sinusitis maxillaris, a large osteoma in the ethmoid sinus on the right side and a pneumocephalus. The surgical procedure included removal of the focus (sinusitis), extirpation of the osteoma and reconstruction of the skull base from an external approach.

Adult↗
PubMed2001

A randomized, double-blind, placebo-controlled trial of single-dose intravenous secretin as treatment for children with autism.

OBJECTIVE: To determine whether a single injection of intravenous secretin results in measurable improvements in socialization and/or communication skills in children with autism. STUDY DESIGN: Sixty subjects with autism were randomly selected and assigned to either treatment or placebo group. Subjects in the treatment group received 2.0 clinical units of secretin per kilogram of body weight as a single intravenous dose. Subjects in the placebo group received normal saline solution. Neurodevelopmental and behavioral assessments were performed for all subjects before injection and at 3 and 6 weeks after injection. RESULTS: Assessment of language skills and parents' behavioral assessments revealed no significant differences between the treatment and placebo groups. Raters' assessments of severity of autistic symptoms did not differ for the 2 groups at 6 weeks after injection. A marginally statistically significant improvement in autistic behaviors was seen in the treatment group at 3 weeks after injection (P =.051). CONCLUSIONS: A single dose of intravenous secretin does not appear to have significant effects on either parents' perception of autistic behaviors or language skills at 6 weeks after injection. Transient, marginally significant improvements in autistic behaviors may occur in some children.

Autistic Disorder↗
PubMed2001

Rhesus monkey (Macaca mulatta) mucosal antimicrobial peptides are close homologues of human molecules.

One component of host defense at mucosal surfaces appears to be epithelium-derived antimicrobial peptides. Molecules of the defensin and cathelicidin families have been studied in several species, including human and mouse. We describe in this report the identification and characterization of rhesus monkey homologues of human mucosal antimicrobial peptides. Using reverse transcriptase PCR methodology, we cloned the cDNAs of rhesus monkey beta-defensin 1 and 2 (rhBD-1 and rhBD-2) and rhesus monkey LL-37/CAP-18 (rhLL-37/rhCAP-18). The predicted amino acid sequences showed a high degree of homology to the human molecules. The expression of the monkey antimicrobial peptides was analyzed using immunohistochemistry with three polyclonal antibodies to the human molecules. As in humans, rhesus monkey antimicrobial peptides are expressed in epithelia of various organs. The present study demonstrates that beta-defensins and cathelicidins of rhesus monkeys are close homologues to the human molecules and indicate that nonhuman primates represent valid model organisms to study innate immune functions.

Animals↗
PubMed2001

Radiologic and endoscopic evaluation for laparoscopic adjustable gastric banding: preoperative and follow-up.

BACKGROUND: Laparoscopic adjustable silicone gastric banding (LASGB) has replaced vertical banded gastroplasty (VBG) as the most widespread restrictive bariatric operation in Europe. Although these two procedures are similar in principle, the experience concerning the preoperative examinations and follow-up cannot be arbitrarily transferred from VBG to LASGB. The reasons for and consequences drawn from radiologic and endoscopic examinations are described. METHODS: From December 1996 to January 2000, 148 patients (84% women, average age 39 years, body weight 127 kg, BMI 45 kg/m2) underwent LASGB. The mean follow-up was 17 months. Upper GI series, abdominal ultrasound, and gastroscopy were done before operation. The postoperative stoma adjustments were performed under radiological observation. All adjustments were analyzed. RESULTS: Preoperative: Of 147 upper GI series, 74 showed hiatal hernia, 2 motility disorders, and 1 an incomplete malrotation. In 104 gastroscopies, 35 reflux and 53 gastritis with 24 Helicobacter pylori infections were found. Postoperative: On average, 2.7 radiological adjustments were done per patient. Until satisfactory satiety and weight reduction, 78% of the patients needed 0-3 adjustments. Besides routine adjustments, an additional 57 upper GI series were done in 35 patients, 44 times with opening of the stoma-diameter. A total of 14 slippages and 4 pouch enlargements were found. A gastroscopy was required in 12 patients. CONCLUSION: Radiologic and endoscopic examinations before LASGB revealed pathology needing therapy in 42% of the patients and provided important additional information influencing the operative procedure. At an average follow-up of 17 months, 24% of the 148 patients needed unplanned additional upper GI series.

Abdominal Pain↗
PubMed2001

Impaired hepatic fatty acid oxidation in rats with short-term cholestasis: characterization and mechanism.

Rats with long-term cholestasis have reduced ketosis during starvation. Because it is unclear whether this is also the case in short-term cholestasis, we investigated hepatic fatty acid metabolism in rats with bile duct ligation for 5 days (BDL5, n = 11) or 10 days (BDL10, n = 11) and compared the findings with those made with pair-fed control rats (CON5 and CON10, n = 11). The plasma beta-hydroxybutyrate concentration was reduced in BDL rats (0.54 +/- 0.10 vs. 0.83 +/- 0.30 mM at 5 days and 0.59 +/- 0.24 vs. 0.88 +/- 0.09 mM at 10 days in BDL and control rats, respectively). In isolated liver mitochondria, state 3 oxidation rates for various substrates were not different between BDL and control rats. Production of ketone bodies from [(14)C]palmitate was reduced by 40% in mitochondria from BDL rats at both time points, whereas production of (14)CO(2) was maintained. These findings indicated intact function of the respiratory chain, Krebs cycle, and beta-oxidation and suggested impaired ketogenesis (HMG-CoA pathway). Accordingly, the formation of acetoacetate from acetyl-CoA by disrupted mitochondria was reduced in BDL rats at 5 days (2.1 +/- 1.0 vs. 4.8 +/- 1.9 nmol/min per mg protein) and at 10 days (1.7 +/- 1.0 vs. 6.2 +/- 1.9 nmol/min per mg protein). The principal defect could be localized at the rate-limiting enzyme of the HMG-CoA pathway, HMG-CoA synthase, which revealed decreased activity, and reduced hepatic mRNA and protein levels. We conclude that short-term cholestasis in rats leads to impaired hepatic fatty acid metabolism due to impaired ketogenesis. Ketogenesis is impaired because of decreased mRNA levels of HMG-CoA synthase, leading to reduced hepatic protein levels and to decreased activity of this key enzyme of ketogenesis. - Lang, C., M. Schäfer, D. Serra, F. G. Hegardt, L. Krähenbühl, and S. Krähenbühl. Impaired hepatic fatty acid oxidation in rats with short-term cholestasis: characterization and mechanism. J. Lipid Res. 2001. 42: 22;-30.

Animals↗