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Biomedical subjects

M Albrecht

Publications and source records attributed to M Albrecht.

At least 91 records · Page 5Linked to original sources
PubMed1996

Pathophysiologic features of a pneumoperitoneum at laparoscopy: a swine model.

OBJECTIVE: The aim of this study was to examine local and systemic reactions of the body to a pneumoperitoneum to elucidate potential dangers and risks of laparoscopic procedures. STUDY DESIGN: Laparoscopy was performed on 25 pigs. The pigs were divided into five groups by level of intraabdominal pressure (14 and 18 mm Hg) and gas used (carbon dioxide and air). The effects of the pneumoperitoneum on cardiopulmonary condition and the peritoneal milieu were observed. These effects should be the result of various changes as the mechanical, ventilatory, cellular, hormonal, and immunologic levels. RESULTS: In this animal study marked changes in the peritoneal milieu were observed, and we demonstrated that these changes were dependent on the gas used, intraabdominal pressure, and duration of application. Locally these changes are manifest in the development of severe peritoneal acidosis, hypercapnia, and the release of various mediators. Systemic changes, in particular cardiopulmonary changes, also depend on the intraabdominal pressure and the gas used. CONCLUSION: During conventional pneumoperitoneum the peritoneum might change to a large extent so that the development of new risks are possibly encouraged. A reduction in intraabdominal pressure with the use of carbon dioxide as the insufflation gas should result in normal acid-base balance.

Abdomen↗
PubMed1996

Effects of intramuscular or interpleural administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy.

OBJECTIVE: To evaluate effects of interpleural or IM administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy. DESIGN: Experimental trial. ANIMALS: 18 healthy dogs. PROCEDURE: Dogs underwent median sternotomy and were randomly assigned to groups of 6 dogs each. Group-A dogs were given morphine (1.0 mg/kg of body weight) i.m.; group-B dogs were given 0.5% bupivacaine (1.5 mg/kg) interpleurally; and group-C dogs were given morphine (1.0 mg/kg) interpleurally. Heart rate; systolic, diastolic, and mean arterial pressures; rectal temperature; pain score; and arterial blood gas partial pressures were measured and pulmonary function testing was performed immediately after extubation (time 0) and up to 48 hours later. Serum cortisol and morphine concentrations were measured at time 0 and up to 12 hours after surgery. RESULTS: There was a significant decrease in pH, PaO2, mean oxygen saturation of hemoglobin, and dynamic compliance; and a significant increase in PaCO2, alveolar-arterial difference in partial pressure of oxygen, pulmonary resistance, and work of breathing for dogs in all groups after surgery. Serum cortisol concentrations were significantly increased, compared with preoperative values, in all dogs. Serum cortisol concentrations were significantly higher in group-B dogs between 3 and 5 hours after surgery, compared with group-A dogs. CONCLUSIONS: Median sternotomy was associated with significant alterations in pulmonary function. Effects of interpleural administration of bupivacaine and morphine were similar to effects of i.m. administration of morphine.

Analgesics, Opioid↗
PubMed1996

[An unusual cause for conversion in laparoscopic cholecystectomy].

The authors describe the case of a female patient who had a planned operation on account of cholecystolithiasis. An unexpected and undiagnosed cavernous haemangioma of the liver at the site of the gallbladder meant a serious complication of the operation and called for conversion. The authors discuss the necessity of detailed pre-operative diagnosis as a means of prevention of unexpected complications and emphasise the necessity of perfect knowledge of classical surgical procedures.

Cholecystectomy↗
PubMed1996

Effects of oral doxycycline administration on histomorphometry and dynamics of subchondral bone in a canine model of osteoarthritis.

OBJECTIVE: To determine whether oral administration of doxycycline, in a dose that inhibits cartilage breakdown in a canine cruciate deficiency model of osteoarthritis (OA), affected formation or resorption of subchondral bone. METHODS: Ten healthy adult mongrel dogs underwent transection of the left anterior cruciate ligament. Five were given doxycycline, 3.5 mg/kg/day, orally, from the day after surgery until they were sacrificed 6 weeks later; the other 5 dogs served as positive OA controls. Three weeks before sacrifice, each dog was given an intravenous injection of the fluorochrome label, calcein, on each of 2 consecutive days; 10 days later, the injection regimen was repeated. At sacrifice, samples of bone from the medial femoral condyle of both knees of each dog were obtained for staining with Villanueva tetrachrome to localize the fluorochrome label and McNeal's tetrachrome for measurement of osteoid and cell counts. RESULTS: Cruciate deficiency resulted in a marked decrease in bone mass, with increased osteoclastic activity and increased bone formation. Doxycycline treatment did not significantly affect either bone formation or bone resorption. CONCLUSION: Doxycycline protects against joint breakdown in this OA model via inhibition of matrix metalloproteinases in articular cartilage, rather than through an effect on subchondral bone.

Administration, Oral↗
PubMed1996

[How to grasp the gallbladder reliably].

The authors describe a new laparoscopic instrument to be used for reliable gripping of tissue. The instrument is very simple from the technical aspect. Due to the firm and reliable grip the preparation of tissue is greatly facilitated. This shortens the operation time and is thus less demanding on the patient. The instrument is used currently in clinical practice and proved very useful.

Humans↗
PubMed1995

Molecular cloning and functional expression in E. coli of a novel plant enzyme mediating zeta-carotene desaturation.

We have cloned a cDNA from the plant Capsicum annuum which encodes a novel enzyme mediating the dehydrogenation of zeta-carotene and neurosporene to lycopene when expressed in E. coli cells accumulating zeta-carotene or neurosporene. This enzyme is unable to dehydrogenate either phytoene or lycopene. The deduced amino acid sequence suggests that this cDNA encodes a polypeptide whose mature size is ca. 59 kDa and which is synthesized as a precursor with a NH2-terminal extension resembling transit peptides for plastid targeting. Sequence comparison reveals 33-35% similarity with previously cloned plant or cyanobacterial phytoene desaturases. In contrast, only limited sequence similarity is found with a zeta-carotene desaturase from the cyanobacterium Anabaena.

Amino Acid Sequence↗
PubMed1995

Cerebral endothelial cells are a major source for soluble intercellular adhesion molecule-1 in the human central nervous system.

Immunohistological analysis of tissue sections from human brain revealed that intercellular adhesion molecule-1 (ICAM-1) is mainly expressed on endothelial cells of small vessels, including the subependymal vessels of the choroid plexus. In addition, it is expressed on cerebrospinal fluid (CSF) cells in patients with inflammatory diseases of the central nervous system. Stimulation of confluent monolayers of adult human cerebral endothelial cells with lipopolysaccharide (LPS) or recombinant human tumor necrosis factor-alpha (TNF-alpha) could induce expression and secretion of soluble ICAM-1 in a dose dependent manner. In addition, sICAM-1 was also present in the supernatant from U251 glioma cells. No sICAM was detected in the culture supernatant from activated blood or CSF lymphocytes. Cerebral endothelial cells are therefore a likely source for sICAM-1 in the CSF.

Base Sequence↗
PubMed1995

Tumor necrosis factor-alpha messenger RNA expression in patients with relapsing-remitting multiple sclerosis is associated with disease activity.

We determined the cytokine messenger RNA (mRNA) expression pattern of blood mononuclear cells in 29 patients with relapsing-remitting multiple sclerosis every 4 weeks over a period of 12 months. During this period 27 relapses occurred in 14 patients (48%). Progression of disease activity as assessed by the occurrence of new lesions on nonenhancing T2-weighted magnetic resonance images of the head was detected in 12 (48%) of 25 patients. Using a semiquantitative polymerase chain reaction we demonstrated significant increases in tumor necrosis factor-alpha mRNA expression in peripheral blood mononuclear cells prior to a relapse. In 24 (85%) of 27 relapses increased tumor necrosis factor-alpha mRNA expression preceded clinical symptoms by 4 weeks. A similar pattern was observed for lymphotoxin mRNA expression. At the same time, transforming growth factor-beta and interleukin-10 mRNA levels declined. Fluctuations in the mRNA expression of tumor necrosis factor-alpha were also observed in 6 patients with stable disease who had active magnetic resonance scans on follow-up. No correlation of disease activity was observed with interleukin-1 beta, -4, or -6, inferferon gamma or endothelin-1 mRNA expression. From these data it can be concluded that variations in cytokine mRNA expression in blood mononuclear cells are correlated with disease activity in relapsing-remitting multiple sclerosis. It may be a valuable parameter to monitor the immunological status of patients in future clinical trials.

Adult↗
PubMed1995

A soluble form of tumour necrosis factor receptor in cerebrospinal fluid and serum of HTLV-I-associated myelopathy and other neurological diseases.

Paired samples of cerebrospinal fluid (CSF) and serum from 17 patients with human T-cell lymphotrophic virus I (HTLV-I)-associated myelopathy, 5 patients with multiple sclerosis and 11 controls with non-inflammatory disorders (migraine, idiopathic epilepsy and myelopathy of unknown aetiology) were examined by enzyme-linked immunosorbent assay for the presence of the 60-kDa soluble form of tumour necrosis factor receptor (sTNF-R). The results were compared with blood-CSF barrier function, cell count and the intrathecal synthesis of HTLV-I antibodies. No correlation could be demonstrated. High levels of sTNF-R were found in CSF of patients with HTLV-I-associated myelopathy and multiple sclerosis. In addition, intrathecal sTNF-R was also detected in the patients with non-inflammatory diseases, indicating that sTNF-R is definitively a normal constituent of CSF.

Blood-Brain Barrier↗
PubMed1995

Semi-quantitative analysis of cytokine gene expression in blood and cerebrospinal fluid cells by reverse transcriptase polymerase chain reaction.

An easy, reproducible and semi-quantitative, non-radioactive method for the analysis of mRNA expression for various cytokines, (i.e., Interleukin (IL)-1 beta, IL-4, IL-6, tumor necrosis factor (TNF)-alpha, lymphotoxin (LT), transforming growth factor (TGF)-beta, interferon (IFN)-gamma and endothelin-1 (ET-1)) in cells from cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) has been established. By means of polymerase chain reaction primers that cover a splice junction, amplification of contaminating DNA was omitted. Densitometric scanning of ethidium bromide-stained agarose gels proved to be very sensitive for semiquantitative analysis of PCR products. Serial tenfold dilutions of cDNA revealed a log-linear regression from 10(6) to 10(2) cells under optimal cycle conditions. The intra- and inter-assay variability of the method was below 10%. With this assay, the cytokine expression pattern of as few as 10(4) mononuclear cells from blood or CSF was determined. This method made it possible to detect differences in the cytokine gene expression pattern of mononuclear cells from patients with different neurological diseases. CSF cells from 43 patients with various neurological diseases were analyzed. TNF-alpha, LT, and IL-1 mRNA were prominent in the CSF cells of most patients with bacterial meningitis. TNF-alpha, LT, IFN-gamma and IL-6 mRNAs were detected in patients with active multiple sclerosis, whereas TNF-alpha, IL-6, and endothelin-1 mRNA expression was found frequently in patients with HIV encephalitis. Pro-inflammatory cytokines were rarely detected in CSF cells from patients with non-inflammatory diseases of the central nervous system. In blood mononuclear cells from patients with multiple sclerosis, TNF-alpha mRNA expression was associated with disease activity. The sensitivity, specificity, velocity and reliability of this assay considerably facilitates the analysis of cytokine production in mononuclear cells even in conditions where only a limited number of cells is available for analysis.

Base Sequence↗
PubMed1995

Soluble forms of intercellular adhesion molecule-1 (ICAM-1) block lymphocyte attachment to cerebral endothelial cells.

Serum levels of circulating ICAM-1 are increased in various disorders including inflammatory diseases of the central nervous system (CNS). We recently described an association between high sICAM-1 levels in the serum of patients with multiple sclerosis and disease activity. The functional consequences of increased circulating adhesion molecules are not fully understood. This may simply arise as a consequence of inflammation or may have immune modulating properties. ICAM-1 plays an important role in the recruitment of activated lymphocytes to sites of inflammation within the CNS. We therefore tested the ability of soluble forms of ICAM-1 to prevent adhesion of activated lymphocytes to cerebral endothelial cells. Mitogen-activated blood mononuclear cells (PBMC) as well as PBMCs from patients with active multiple sclerosis adhered to cerebral endothelial cell cultures in vitro. This adhesion could be blocked if lymphocytes were preincubated with a recombinant form of soluble ICAM-1. In addition, serum from patients with active multiple sclerosis and high sICAM-1 levels blocked adhesion in a dose-dependent manner which was abrogated by pre-adsorption to an anti ICAM-1 antibody. Since soluble forms of ICAM-1 are able to block lymphocyte adhesion to cerebral endothelial cells, they may provide new therapeutic tools to interfere with the pathogenesis of inflammatory diseases of the CNS.

Cell Adhesion↗
PubMed1995

Comparative pharmacokinetics of fluconazole and of itraconazole in Japanese and in German subjects.

In separate but identically designed studies the oral pharmacokinetics of 100 mg doses of the 2 antimycotics fluconazole and itraconazole were examined in Japanese and German subjects (both n = 12), both fasting and concomitant to a heavy breakfast. The results with the 2 races were compared. With fasting subjects no significant difference was found with either antimycotic for any parameter. With fluconazole the pharmacokinetic parameters after food were essentially the same for the 2 races. The only significant difference, a delay of 1.5 h in the median tmax in the Japanese relative to the Germans, should not be of practical importance. In contrast, the mean AUC for itraconazole in Japanese subjects after the meal was only 54.9% of the value with Germans (p < 0.05); the corresponding Cmax was only 54.7% (p < 0.01). As itraconazole is normally administered together with food, this suggests that there is a possibility of underdosage in Japanese subjects. There appears to be no such problem with fluconazole.

Administration, Oral↗