PubMed Health⌕ Search

Biomedical subjects

K Westphal

Publications and source records attributed to K Westphal.

71 records · Page 4Linked to original sources
PubMed1997

[Exposure of the pediatric surgeon to inhalation-anesthetic during pediatric bronchoscopy procedures].

BACKGROUND: General anaesthetic agents are frequently used for paediatric bronchoscopy. A disadvantage of this open system anaesthesia seems to be the contamination of the working environment. The aim of this study was to determine the exposure of the endoscopist during paediatric bronchoscopy under general anaesthesia in different working environments and to compare these measurements with the currently valid international threshold limit values. MATERIAL AND METHODS: 25 children (ASA I-III) scheduled for diagnostic bronchoscopy were included in the study. After inhalational induction all children were intubated with a nonflexible bronchoscope and manually ventilated through a side arm of the bronchoscope. Maintenance of anaesthesia was achieved with sevoflurane (2-3 vol%) in 80% oxygen. Trace concentrations were measured every 90 seconds in the breathing zones of the paediatrician by means of a highly sensitive direct-reading instrument (Brüel & Kjaer 1302). The lower detection limit was 0.02 ppm. The investigation was done in an OT with and without air conditioning and scavening system. RESULTS: The mean age of the children was 50.3 months (range: 3-109 months). Ventilation and oxygenation were stable throughout the bronchoscopic procedure. Mean exposure of the paediatrician without air-conditioning and scavening system to sevoflurane was over 50 ppm for the endoscopist. All international threshold limit values were exceeded. Peak concentrations higher than 100 ppm sevoflurane were detected repeatedly in 40% of anaesthesias. During bronchoscopy in the operating room equipped with laminar air flow (20.2 air exchanges per hour) and narcotic gas evacuation (30 l/min) the mean exposure of the paediatrician was 26.4 ppm sevoflurane. CONCLUSIONS: The main finding of the present study is that under inhalation anaesthesia with sevoflurane for paediatric bronchoscopy occupation exposure is higher than the limits stated in all known health regulation guidelines. Therefore, in case of such working conditions, the use of total intravenous anaesthesia is advocated also in very small infants.

Adult↗
PubMed1993

Purification of Coxiella burnetii antigen by gel-chromatography for use in enzyme-linked immunosorbent assay (ELISA).

Cell wall antigens from Coxiella burnetti were extracted by heat, ultrasonication, phenol, SDS or sodium deoxycholate. These antigens were subsequently purified by gel-chromatography yielding molecular weights of 700 and 270 KD. Using gel-chromatographical purification of antigens extracted by heat, ultrasonication or phenol Coxiella antigens nearly devoid of contaminations could be obtained. Of these highly purified antigens heat extracted antigen was treated with proteases, lysozyme or metaperiodate exemplarily. These treatments did neither destroy nor change its antigenic activity, except for the treatment with metaperiodate reducing the antigenic activity significantly. In further experiments heat extracted and gel-chromatographically purified Coxiella antigen was used for testing bovine sera in ELISA.

Animals↗
PubMed1989

Biomonitoring after controlled exposure to environmental tobacco smoke (ETS).

A rough estimation of the amounts of tobacco smoke components taken up by active and passive smoking suggests that, in the case of passive smoking, gas phase constituents in ETS are of greater relevance than particle-bound substances. Since this aspect is of importance for the risk evaluation of passive smoking, it was decided that it should be investigated further in a series of exposure studies with human volunteers. The ETS exposure conditions were characterized by measuring tobacco smoke components such as carbon monoxide (CO), nitrogen oxides (NOx), nicotine, formaldehyde, tobacco-specific nitrosamines (N-nitrosonornicotine (NNN), 4-methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), benzo(a)pyrene (BaP) and particulate matter in the air of the exposure room. The biomonitoring covered carboxyhemoglobin (COHb), thioethers and mutagenic activity in urine. These parameters were compared to those observed after controlled active smoking. It was found that urinary thioether excretion increased in non-smokers after extremely high ETS exposure. This effect could be attributed to gas phase ETS components. Urinary mutagenicity was not measurably increased in non-smokers under these conditions. This indicates that in passive smoking, as opposed to smoking, the gas phase might be more important in terms of possible effects than the particulate matter. It would, therefore, be misleading to make extrapolations based on the burden of smoking to establish the burden of passive smoking.

Adult↗
PubMed1987

Urinary mutagenicity after controlled exposure to environmental tobacco smoke (ETS).

20 non-smokers on a defined diet low in polycyclic aromatic hydrocarbons (PAH) were exposed to environmental tobacco smoke (ETS) in an unventilated room for 8 h. The urinary mutagenicity in the 24-h urine samples as tested with the Salmonella (TA98) microsome assay did not significantly increase after exposure to either 10 ppm CO or 20-25 ppm CO. We conclude that exposure of non-smokers to ETS does not lead to an increase in their urinary mutagenicity, provided the exposure conditions are within a realistic range.

Adult↗
PubMed1982

Test-condition-dependent influence of harman and nonharman on benzo[a]pyrene mutagenesis in Salmonella.

The enhancing or decreasing effect of harman or norharman on benzo[a]pyrene mutagenesis depends mainly on the metabolizing system (S9) used. When mammalian activation was performed by using liver homogenates from mice induced by 3-methylcholanthrene, phenobarbital or Aroclor 1254, then the mutagenicity of benzo[a]pyrene in Salmonella typhimurium TA98 decreased upon addition of harman or norharman. In the presence of rat-liver homogenate induced by Aroclor 1154, however, harman enhanced the number of benzo[a]pyrene revertants, whereas norharman did not show any significant alteration of the benzo[a]pyrene mutagenicity. Further tests carried out with phenobarbital-induced mouse-liver homogenate showed that, within certain limits, neither variations of the amount of S9 extract nor the amount of the cofactors nor the relative proportions of the test substances had any influence on the antagonistic effect of harman or norharman on the benzo[a]pyrene mutagenesis.

Alkaloids↗
PubMed1981

Myelin sheath maturation of intrapulmonary axon bundles in the rabbit fetus.

The development of intrapulmonary myelin sheaths began in the central parts of the lung and proceeded towards the periphery. It started suddenly on the 25th post conceptional (p.c.) day. Early stages of myelination could be demonstrated in the periphery on the 27th day p.c (2) Axons not surrounded by Schwann cells could be seen in large numbers on the 24th and 25th day p.c. but they became fewer on the following days. (3) Myelinated axons was found were often at the periphery of the axon bundle. The maximum number of myelin layers was 7 on the 25th day p.c. and 30 on the 31st day p.c. (4) Axons at early stages of myelination were seen along with axons with more progressive myelin sheath development. Abnormal structures of myelinated fibers could be demonstrated. Their significance is discussed.

Animals↗
PubMed1980

Mast cells in cluster headache.

Temporal skin biopsies were performed in six cluster headache patients and controls. In biopsies, mast cells were examined by light and electron microscopy for possible deviations in number, distribution and morphology. Three patients were in a headache phase, the other three in a headache-free interval. No differences between controls and patients could be observed. The results are discussed.

Adult↗
PubMed1979

Deoxyribonucleic acid in Nitrobacter carboxysomes.

Carboxysomes were isolated from Nitrobacter winogradskyi and Nitrobacter agilis. The icosahedral particles contained double-stranded deoxyribonucleic acid (DNA). In the presence of ethidium bromide and cesium chloride, the particle-bound DNA had a buoyant density of rho 25 = 1.701 g/cm3. Electron microscopy revealed the DNA to be a 14-micron circular molecule.

Centrifugation, Density Gradient↗
PubMed1977

Icosahedral inclusions (carboxysomes) of Nitrobacter agilis.

The icosahedral bodies of Nitrobacter agilis are about 120 nm in diameter and, as viewed by electron microscopy, consist of an outer shell enclosing 10-nm particles. The inner 10-nm particle is the enzyme D-ribulose 1,5-bisphosphate carboxylase. The bodies isolated from cells incubated 1 month without nitrite had a specific activity for the enzyme of 0.54 mu mol of CO2 fixed per min per mg of protein.

Carbon Dioxide↗
PubMed1977

[Brain infarctions during treatment with ovulation inhibitors (author's transl)].

392 cases of cerebrovascular disturbances in women while taking oral contraceptives are reported since 1962. There has been a remarkable change of the distribution of age among these women. Till 1970 were mostly women involved between the age of 30 and 34 years. Today this type of distribution is no more to be seen because of the growing number of reports about complications in other age-groups. Complications were till 1970 mostly reported in the period from ten days till six months after taking oral contraceptives. The publications of the last three years are showing that many women are involved, who had taken oral contraceptives more than two years. New publications and our own results are showing no changes of the clinical syndromes and of the prognosis. Our investigation shows no decrease in the number of young women suffering of thromboembolic cerebral disorders of unknown aetiology in the last years. In this group is the percentage of the women, which had taken ovulation inhibitors, no reduced. The conception, that there is a connection between oral contraceptives and cerebrovascular occlusions seems more possible as before. Especially attention in prescription of oral contraceptives should be given to the fact of a known predisposition. The rareness of these complications leads to the conclusion that one or more predisponating factors of a nature not yet known have to be existent.

Adult↗
PubMedDate not supplied

Complications of port-access cardiac surgery.

Port-Access cardiac surgery is a recent technology that is undergoing rapid development. The learning curve associated with this technique is a challenge even for the skilled and experienced cardiac surgeon. Mainly because of femoral cannulation, the use of guidewires, and working through small incisions, Port-Access cardiac surgery contains certain pitfalls that are clearly associated with the technology involved. These pitfalls currently require troubleshooting, but as the technology progresses, this may become less of an issue. Communicating these pitfalls to others is important to help others to avoid or better manage complications and to contribute to improving the technology of Port-Access techniques.

Cardiac Surgical Procedures↗
PubMedDate not supplied

The micro-mitral operation comparing the Port-Access technique and the transthoracic clamp technique.

BACKGROUND: Several minimally invasive approaches to the mitral valve have been described, including parasternal incision and right anterolateral thoracotomy. MATERIAL AND METHODS: Since September 1996, 58 patients underwent minimally invasive mitral valve surgery at our institution through a right anterolateral minithoractomy. Two different techniques were used for institution of cardiopulmonary bypass (CPB) and aortic clamping: in the Port-Access group (group A) patients had femoro-femoral cannulation with a special arterial cannula to introduce an endoaortic balloon clamp (n = 23). The second group (group B) of patients underwent femoro-femoral CPB as well in combination with a specially designed transthoracic aortic clamp (Chitwood technique, n = 35). Patients were assigned to either technique in a nonrandomized fashion. Demographics were similar in both groups. RESULTS: In group A, 4 valves were replaced, 19 patients had mitral valve repair. In group B, 7 patients had valve replacement and 28 patients underwent mitral repair. Four patients in group A were converted to Chitwood technique due to endoclamp dysfunction. Operating time, CPB time, cross-clamp time, and postoperative blood loss were lower in group B (operating time 295 +/- 83 min vs. 236 +/- 63.9 min; CPB min 167.6 = 64.9 min vs. 137.6 +/- 38.2 min; cross-clamp time 105.9 +/- 51.7 min vs. 78.9 +/- 25.2 min; postoperative blood loss 584 +/- 428 mL vs. 323 +/- 209 mL [p < 0.05]). Clinical outcome regarding postoperative mechanical ventilatilation time, hospital stay and hospital mortality was not different between groups. CONCLUSIONS: Minimally invasive mitral valve procedures via right anterolateral minithoracotomy, including complex valve repair, can be performed successfully using either technique. However, the Chitwood technique provides better intraoperative handling with shorter operation time and less postoperative blood loss. Additionally, costs of a procedure are less using the Chitwood technique compared to the Port-Access technique.

Adolescent↗