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Biomedical subjects

J Janzen

Publications and source records attributed to J Janzen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Takayasu's arteritis and fibromuscular dysplasia as causes of acquired atypical coarctation of the aorta: retrospective analysis of seven cases.

Coarctation of the aorta usually occurs in the aortic isthmus: however, 2% of all coarctation is localized at atypical sites such as the aortic arch and the thoracic and/or abdominal aorta. Causal therapy involves vascular surgery, and during the procedure, biopsies of the involved vessels should be taken to establish the etiology. This study involved the retrospective analysis of clinical and histopathological findings for seven patients who underwent vascular surgical procedures (age range, 10-37 years; male/female ratio 3:4). Histopathological analysis of specimens revealed two pathological processes taking place with different localization in the aortic wall as the cause of the atypical coarctation of the aorta: (1) fibrosis/scarification in the tunica media and adventitia compatible with chronic lesions of Takayasu's arteritis (four cases); (2) fibromuscular dysplasia in the tunica media (three cases).

Adolescent↗
PubMed1998

Inhibition of liposome-induced complement activation by incorporated poly(ethylene glycol)-lipids.

Complement activation causes opsonization of foreign particles leading to particle elimination from the blood. Complement-mediated opsonization of charged and large liposomes presents a fundamental problem in their use to deliver therapeutic agents in vivo. To prolong the circulation half-lives of such liposomes, complement activation must be curtailed. The aim of this study was to assess the ability of poly(ethylene glycol)-lipids (PEG-lipids) to inhibit the in vitro activation of the classical pathway of complement in human serum by anionic liposomes. Incorporation of cholesterol-PEG600 (CH-PEG600), cholesterol-PEG1000 (CH-PEG1000), or phosphatidylethanolamine-PEG2000 (PE-PEG2000) resulted in dose-dependent inhibition of C1q binding and complement activation. The dose of PEG-lipid at which complement activation was blocked was inversely related to the PEG chain length. Complement activation was strongly inhibited when 15 mole% of CH-PEG600, 10 mole% CH-PEG1000, or 5 mole% PE-PEG2000 was incorporated into 100-nm anionic liposomes. PEG-lipid incorporation into larger liposomes (240 nm) was also successful in blocking C1q binding and complement activation. Radiolabeled cholesterol-PEG approximately 1400 was prepared and used to determine both the percentage of CH-PEG incorporated into the liposomes and the percentage maintained in the liposomes in the presence of 50% human serum at 37 degrees C for up to 24 h.

Cholesterol↗
PubMed1998

Bladder tissue biopsies in spinal cord injured patients: histopathologic aspects of 61 cases.

It was the aim of this histopathologic study to examine and compare results of bladder tissue biopsies in spinal cord injured (SCI) patients. The study group consisted of 61 SCI patients who received treatment at the Swiss Paraplegic Centre in Nottwil, near Lucerne, Switzerland. The mean age of the study group was 41 years (range, 17-73) and the mean duration of spinal cord lesion was 10 years and 4 months (range, 5 months to 44 years). The male:female ratio was 57:4. Bladder infections had occurred in each patient one to six times per year (median, 3.2). All samples were taken from the trigone of the bladder during endoscopic urologic procedures with a flexible cystoscope. Histopathologic analysis showed abnormal alterations of bladder tissue in 56 SCI patients (91.8%). Forty-six SCI patients (75.4%) had a chronic type and 10 SCI patients (16.4%) a subacute type of inflammation. Normal bladder tissue was found in five cases (8.2%). Further observation revealed the presence of fibrosis (34.4%), edema (9.8%), and lymphoid hyperplasia (6.6%). A t-test for independent samples showed a lack of significant correlation between the number of clinical bladder infections per year, the duration of injury, the neurologic level of the spinal cord lesion, and histopathologic types of infections.

Adolescent↗
PubMed1997

Glutamate transporter EAAC-1-deficient mice develop dicarboxylic aminoaciduria and behavioral abnormalities but no neurodegeneration.

Four L-glutamate neurotransmitter transporters, the three Na(+)-dependent GLAST-1, GLT-1 and EAAC-1, and the Cl(-)-dependent EAAT-4, form a new family of structurally related integral plasma membrane proteins with different distribution in the central nervous system. They may have pivotal functions in the regulation of synaptic L-glutamate concentration during neurotransmission and are believed to prevent glutamate neurotoxicity. To investigate the specific physiological and pathophysiological role of the neuronal EAAC-1, which is also expressed in kidney and small intestine, we have generated two independent mouse lines lacking EAAC-1. eaac-1(-/-) mice develop dicarboxylic aminoaciduria. No neurodegeneration has been observed during a period of >12 months, but homozygous mutants display a significantly reduced spontaneous locomotor activity.

Amino Acid Sequence↗
PubMed1997

Toxin production by Burkholderia pseudomallei strains and correlation with severity of melioidosis.

An exotoxin lethal to cells in culture (cytolethal toxin, CLT) was identified in culture filtrates of Burkholderia pseudomallei, the causative organism of melioidosis. CLT could pass through a 10-kDa cut-off ultrafilter and its properties suggest that it is a peptide. Isolates from soil, animals and man showed differential cytolethality in vitro. The isolates were divided into low, medium and high CLT producers with soil isolates being low producers and isolates from patients with melioidosis encephalitis being high producers. CLT levels are subject to regulation, as a strain isolated from an infected goat was one of the highest producers whereas the same strain isolated from soil was a low producer. In addition to CLT, all isolates produced a protein with cell-elongating activity which was also present in culture filtrates.

Animals↗
PubMed1997

The oral hygiene and gingival health of paraplegic inpatients--a cross-sectional survey.

Physical and/or mental handicaps are known to directly or indirectly compromise hygiene habits including oral hygiene. It is recommended that handicapped patients, their parents or care workers require from an early stage dental health education and active involvement in preventive programmes. This study surveyed the oral hygiene of paraplegic patients in a specialised centre to determine their oral hygiene needs. Most patients had moderate to poor oral hygiene and gingivitis was prevalent and severe. Plaque and gingivitis was increased in quadriplegic compared to hemiplegic patients. The data indicate that as part of rehabilitation of paraplegic patients there is a need for oral hygiene programmes to be established.

Adolescent↗
PubMed1996

Interfacial thickness of liposomes containing poly(ethylene glycol)-cholesterol from electrophoresis.

The electrophoretic mobilities of liposomes incorporating a polyethylene glycol (PEG) headgroup coupled to cholesterol for PEG of average chain index 3.0, 13.2, and 22.3 have been determined as a function of PEG-cholesterol mole fraction between 5% and 40% and ionic strength between 2 and 200 mM. The liposome compositions were 40 mole % cholesterol plus PEG-cholesterol, 10 mole % 1,2-dipalmitoyl-sn-glyerco-3-phosphoglycerol, and 50 mole % egg phosphatidylcholine. The mobilities were fit to a model in which the PEG forms a surface layer of polymer subject to viscous drag arising from electroosmotic flow within this layer. The model provides estimates of the average layer thickness that are comparable to those determined from contemporary models of surface-attached polymer.

Biophysical Phenomena↗
PubMed1995

Fibromuscular dysplasia causing atypical coarctation of the thoracic aorta: histological presentation of a case.

The authors report a case of atypical coarctation of the thoracic aorta discovered by chance in a 37-year-old man, victim of a car accident. The angiogram revealed a "string-of-beads" contour in the coarctate area while the left subclavian artery presented a severe stenosis at its origin. Vascular checkup examination failed to identify any additional vascular anomaly. The patient underwent surgical resection, with a Dacron prosthetic bypass. Histological study of the specimen removed, showed a typical perimedial and extensive medial types of fibromuscular dysplasia (FMD) of the aorta. Pathogenesis of this disease is discussed.

Adult↗
PubMed1993

[The disease picture of atypical aortic coarctation].

The atypical coarctation of aorta is a very rare disease. Approximately 1-2% of all coarctations are not localized in isthmus aortae. The etiology of this disease is still unknown. There are existing opinions about acquired and also congenital origin.

Adult↗
PubMed1989

Involvement of the MN blood group antigen in shear-enhanced hemagglutination induced by the Escherichia coli F41 adhesin.

An adhesin from Escherichia coli F41 with an apparent subunit molecular weight of 28,000 daltons was isolated by using (NH4)2SO4 precipitation at pH 10 and Sephacryl S-500 gel filtration. The hemagglutination (HA) properties of the native high-molecular-weight adhesin were studied by using a viscometric assay, which provided a quantitative index of the degree of agglutination present as a function of time at a known rate of shear. Shear was found to enhance the degree of agglutination over a 20-min period. A strong, shear-enhanced HA was observed for all donors with the MM or MN blood type studied, but those with the NN blood type showed very little HA. In the microtiter HA assay, the selectivity of the adhesin for MM over NN erythrocytes was found to be dependent on pH and temperature. At 21 degrees C and pH 7.4, there was little difference in HA between the two blood types, but NN cells were progressively more weakly agglutinated than MM cells as the pH or the temperature was increased. Glycophorin A, which bears the M or N determinant, was isolated from individuals with the MM and NN blood types and was shown to be an effective inhibitor of the reaction, with the MM type being the more effective in both microtiter and viscometric assays. Acidic monosaccharides, particularly sialic acid, were also effective inhibitors of HA, although they were less potent on a molar basis than glycophorin. The adsorption isotherm of 125I-labeled adhesin was measured, and the binding was shown to be strongly inhibited by MM glycophorin and somewhat less strongly by NN glycophorin. Collectively, these data strongly suggest that glycophorin AM is a receptor for the F41 adhesin.

Adhesins, Escherichia coli↗
PubMed1989

Epidural analgesia in the management of symptomatic symphysis pubis diastasis.

The pain of symphysis pubis diastasis during and after pregnancy can be disabling. This report describes for the first time the successful use of epidural analgesia in relieving the pain of this disorder. Our patient had been confined to bed or chair for 10 weeks. The epidural analgesia described allowed her to mobilize immediately and remain normally active for the remainder of her pregnancy. Early consultation with an anesthesiologist in severe cases of symphysis pubis diastasis is encouraged.

Adult↗
PubMed1986

[Not Available].

Explore the source record for details and available documents.

Africa↗
PubMed1978

Epidemiology of hepatitis B surface antigen (HBsAg) and antibody to HBsAg in hospital personnel.

The epidemiology of hepatitis B in hospital personnel was studied by testing of sera from 3,770 employees of the Medical School of Hannover (Hannover, West Germany) for hepatitis B surface antigen (HBsAg) and its corresponding antibody (anti-HBs) by solid-phase radioimmunoassay. An average prevalence of 2.2% for HBsAg and 11.7% for anti-HBs was found. Physicians (18.2%), nurses (20.1%), and members of the cleaning service (26.3%) showed the highest frequencies of HBsAg or anti-HBs carriage. In a study of age- and sex-matched personnel, nurses showed a significantly (P less than 0.01) higher rate of infection than a control group with less exposure to infectious materials. The frequency of HBsAg or anti-HBs was highest in persons associated with dialysis (31.3%), anesthesiology (31.0%), ophthalmology (29.4%, neurosurgery (28.0%), and surgery (24.4%). The rate of infection was significantly higher in surgical departments (24.4%) than in nonsurgical ones (13.3%). Persons who had been nursing patients with hepatitis were significantly (P less than 0.05) more frequently carriers of HBsAg or anti-HBs than a comparable control group.

Adult↗