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Biomedical subjects

P Pohl

Publications and source records attributed to P Pohl.

At least 91 records · Page 5Linked to original sources

[Control of serum concentration of anticonvulsants in pregnancy].

In a prospective study we investigated the serum concentrations and frequency of seizures in 38 women with epilepsy in a total of 44 pregnancies. Monthly follow-up examinations were carried out in cooperation with the risk outpatient unit of the Department of Gynecology. Antiepileptic serum concentrations were determined using the technique of fluorescence polarisation. At constant dosage, a decrease in serum concentration occurred in most cases with a maximum at the 5th and 6th month of gestation, regardless of the kind of antiepileptic medication. No changes in seizure frequency have been observed. The treatment of epilepsy during pregnancy should in any case depend on the course of the illness, rather than on laboratory parameters.

Adult↗

Kinetic properties of cation/H(+)-exchange: calcimycin (A23187)-mediated Ca2+/2H(+)-exchange on the bilayer lipid membrane.

The calcimycin (A23187)-mediated electrically silent flux of hydrogen ions coupled with a counter transport of calcium or magnesium ions was measured by the method of local pH changes recording in the unstirred layers near the planar bilayer lipid membrane (BLM). It was shown that: (1) the pH dependence of calcimycin-mediated Ca2+/2H+ exchange had a maximum at pH 7; (2) the apparent Michaelis constant for the alkali earth cations were higher at acidic pH than the corresponding values at alkaline pH; (3) the apparent Michaelis constant for calcium was similar to that for magnesium ions in agreement with calcimycine cation binding constants; (4) the ratio of calcium and magnesium fluxes was independent of pH in the pH range from 5 to 8. (5) the flux was proportional to the calcimycin concentration at pH greater than 6.3 and proportional to the square of the carrier concentration at pH less than 5; (6) the addition of calcium ion chelator EDTA increased the flux significantly. These data were discussed in terms of the model of cation/H(+)-exchange and it was concluded that the dissociation of the cation-carrier complex at the membrane/water interface played an important role in the process of calcimycine operation. The comparison of the kinetic properties of calcimycin with the previously described kinetics of nigericin (Antonenko and Yaguzhinsky (1988) Biol. Membr. (Russian) 5, 718-728) revealed much similarity. On the other hand, a significant difference was found between the mechanism of the nigericin K/Na selectivity and calcimycin Ca/Mg selectivity.

Binding, Competitive↗

Prevalence of four enterotoxin (STaP, STaH, STb, and LT) and four adhesin subunit (K99, K88, 987P, and F41) genes among Escherichia coli isolates from cattle.

Colony hybridizations with DNA probes for 3 heat-stable (STaP, STaH, and STb) enterotoxins and 1 heat-labile (LT) enterotoxin and for 4 adhesins (K99, F41, K88, 987P) were performed on 870 Escherichia coli isolates to determine pathotypes prevalent among enterotoxigenic E coli (ETEC) isolated from cattle in Belgium. One hundred thirty-two E coli isolates (15.2%) hybridized with probes STaP, K99, and/or F41. The 5 other probes were not hybridized by E coli isolates. Therefore, only STaP enterotoxin and K99 and F41 adhesins were virulence factors of ETEC isolated from cattle. Two major pathotypes accounted for 95% of the ETEC: STaP+K99+F41+ (67.4%) and STaP+K99+ (27.3%). The last 5% of probe-positive isolates had STaP+, STaP+F41+, or K99+F41+ minor pathotypes. Of 12 American ETEC isolates also assayed, 7 were positive with STb and/or 987P probes (pathotypes STaP+STb+, STaP+ 987P+, or STaP+STb+987P+) and may be porcine- rather than bovine-specific enteropathogens. The remaining 5 American ETEC isolates belonged to 3 minor pathotypes (STaP+, STaP+F41+, and K99+F41+) also found among Belgian E coli isolates. Such isolates may be derivatives of STaP+K99+F41+ or STaP+K99+ ETEC after in vivo or in vitro loss of virulence genes and/or non-ETEC isolates, which have acquired virulence genes by in vivo transfer.

Adhesins, Escherichia coli↗

[Pathologico-morphologic changes in the digestive system in rabid foxes].

Pathologico-morphological changes in the digestive tract were investigated in fifty naturally infected common foxes (Vulpes vulpes crucigera). Nineteen animals were found to suffer from mild cachexia, 31 animals suffered from complete cachexia. Erosions were observed in the mucosa of oral cavities of 21 foxes. Traumatic injuries appeared in the teeth of 11 animals. One case of swollen and hyperaemic tongue was described; in three cases there occurred sialo-adenitis. A mild degree of inflammation was recorded in the gullet in three animals. Fifteen animals had empty stomachs, thirty-five animals had atypical food or foreign bodies in the stomach contents; simple hyperaemia was recorded 18 times, acute catarrhal gastritis 19 times and haemorrhagic gastritis was observed in two cases. Acute catarrhal enteritis was found in six cases, haemorrhagic enteritis in one case.

Animals↗

Vacuolar myelopathy with multinucleated giant cells in the acquired immune deficiency syndrome (AIDS). Light and electron microscopic distribution of human immunodeficiency virus (HIV) antigens.

Vacuolar myelopathy (VM) is a frequent neurological complication of the acquired immune deficiency syndrome (AIDS). A suspected connection between VM and human immunodeficiency virus (HIV) has been based only on HIV isolation from affected spinal cord tissue. We report here an AIDS patient dying after 14 months of progressive dementia, including 3 months of spinal signs and symptoms. At autopsy, the brain revealed moderate diffuse damage of the white matter compatible with HIV-induced progressive diffuse leukoencephalopathy. The spinal cord showed VM mainly in the lateral and the posterior columns. Mono- and multinucleated macrophages were localized within intramyelinic and periaxonal vacuoles. Light and electron microscopic immunocytochemistry revealed the presence of HIV antigens restricted to mono- and multinucleated macrophages within the spongy lesions. Productive HIV infection is documented for the first time within VM lesions of this case. Therefore, VM should be included among HIV-induced lesions of the central nervous system. The intimate relation of infected macrophages to vacuolar myelinopathy could suggest secretion of a myelinotoxic factor by macrophages productively infected by HIV. Immune electron microscopy appears as promising tool to detect HIV in tissue even when the density of virus may be low.

AIDS Dementia Complex↗

Doppler and duplex sonography of the cervical arteries and correlations with other examinations. A field study in a population over forty years.

Of the population of a small Tyrolean village, 185 (56%) of the 329 inhabitants over 40 years were investigated by means of Doppler and duplex sonography, electroencephalography (EEG), electrocardiography (ECG), and neurological examination. Four subjects (2%) previously had a transitory ischemic attack (TIA) or stroke in the carotid territory. Sonographically detectable abnormalities in one or more extracranial arteries were present in 42 (23%) persons. Of the 14 subjects with more than slight abnormalities in the common or internal carotid artery two were symptomatic. Two additional cases with TIA or stroke did not show relevant lesions on sonographic examination. The presence of narrowing in the extracranial artery was not related to risk factors (hypertension, smoking, obesity) or abnormalities on ECG and EEG. This study shows 1) that the clinical relevance of ultrasound screening of the carotid arteries in an average population is 15%; 2) that significantly more patients with TIAs or strokes are found in the group with more severe sonographic findings (p = 0.001) than in the group with normal ultrasound results.

Carotid Arteries↗

Steroid-induced complete remission in a case of primary cerebral non-Hodgkin's lymphoma.

A case of a primary non-Hodgkin's lymphoma of the CNS is reported in which a complete and stable disappearance of an enhancing mass lesion on the CT scan after treatment with dexamethasone was followed by the occurrence of a high-grade malignant lymphoma in the opposite hemisphere 18 months later. The long-lasting and stable remission suggests a direct oncolytic effect of corticosteroids on lymphoma cells. Furthermore, this case illustrates the usefulness of repeated CT examinations in patients with CNS lymphoma and steroid treatment.

Aged↗

Detection and identification of pathotypes of verocytotoxigenic Escherichia coli isolated from weaned piglets using gene probes for seven E. coli toxins.

Seventy verocytotoxigenic (VTEC) and sixty-three non VTEC haemolytic Escherichia coli isolated from recently weaned piglets were examined by the colony hybridization assay using gene probes for three verocytotoxins: Edema disease principle (EDP) and Shiga-like toxins I and II (SLTI and SLTII). The results with the EDP and SLTII probes were identical. All VTEC hybridized with these two probes, while non VTEC did not. All 133 E. coli were negative for the SLTI probe. Hybridization of the plasmid content of 14 VTEC did not show any evidence for plasmid localization of the genes coding for the EDP. The 70 VTEC were also assayed with gene probes for heat-stable (STaP, STb) and heat-labile (LT, LTIIa) enterotoxins. Only the STb probe was hybridized by 36 of them. Most STb-positive isolates belonged to serotype O141: K85 biotypes 9 and 13 PC.

Animals↗

Retroviral infections (HIV-1, HIV-2, and HTLV-I) in rural northwestern Tanzania. Clinical findings, epidemiology, and association with infections common in Africa.

During a three-week period in March/April 1987, the authors examined 253 consecutive patients referred to a rural hospital in northwestern Tanzania. Sera were tested for antibodies to human immunodeficiency virus type 1 (HIV-1), human immunodeficiency virus type 2 (HIV-2), and human T-lymphotropic virus type I (HTLV-I), as well as for various parasites, hepatitis B virus, and Treponema pallidum. Neopterin (urinary and serum) was chosen as the immunologic parameter. In eight of the 253 patients (3.2%), a clinical diagnosis of acquired immunodeficiency syndrome (AIDS) was established. Three of the AIDS patients had HIV-1 antibodies, two had HIV-1 antigen, one had both HIV-1 and HIV-2 antibodies, and in one patient, only HIV-2 antibodies were found. The total HIV-1 and HIV-2 seroprevalence (antibodies plus antigen) was 4.3%; HTLV-I seroprevalence was 9.9%. No correlation could be found between HIV (or HTLV-I) seropositivity and raised levels of antibody to the above pathogens. There was, however, a significantly positive correlation between HIV seropositivity and history of gonorrhea, whereas a history of operations, injections, vaccinations, blood transfusions, or scarification did not influence the level of HIV seropositivity. The most frequently noted epidemiologic association with HIV seropositivity was traveling to or coming from Uganda or Rwanda. Two thirds of the studied Tanzanians had elevated neopterin levels, and all seven HIV-seropositive patients with clinical signs of AIDS had extremely high serum and urinary neopterin levels compared with HIV-seropositive patients without signs of AIDS. Increased neopterin levels reflect a stimulation of the T-cell/macrophage system.

Acquired Immunodeficiency Syndrome↗

[Sonographic determination of the position of the carotid bifurcation as a diagnostic aid in cerebral catheter angiography].

A simple sonographic method is described for demonstrating the position of the carotid bifurcation in the sagittal plane. As a result, it is possible to demonstrate the bifurcation by angiography without overlay, thereby improving the diagnosis of vascular abnormalities. Since non-invasive sonography of the carotid arteries should be carried out before cerebral angiography in any case, the present procedure does not involve any additional effort.

Carotid Arteries↗

Isolation and nucleotide sequence of the F17-A gene encoding the structural protein of the F17 fimbriae in bovine enterotoxigenic Escherichia coli.

The genetic determinant for production of the fimbrial F17 adhesive antigen was isolated from a bovine enterotoxigenic Escherichia coli strain. The F17-A gene, coding for the structural component of the F17 fimbrial adhesin, was cloned and sequenced. An open reading frame of 540 base pairs encoding a polypeptide of 180 amino acids, of which the NH2-terminal 21 residues are characteristic of a signal sequence, has been characterized. The mature protein lacks histidine, methionine, and tryptophan. A possible promoter and ribosome binding site as well as a possible site for termination of transcription are proposed. An important homology of the F17-A protein with fimA and papA fimbrial proteins was found. The N-terminal sequence of the mature F17-A pilin is extremely similar to the N-terminal sequence of the G fimbriae identified on human pyelonephritogenic E. coli strains.

Amino Acid Sequence↗

Borrelia burgdorferi antibodies in patients with relapsing/remitting form and chronic progressive form of multiple sclerosis.

Sera of 106 multiple sclerosis patients and 103 closely matched controls were examined for Borrelia burgdorferi antibodies. The prevalence rate in multiple sclerosis patients was 14.2%, in controls 25.2%. Overall prevalence was 20.1%. Mean IgG antibody level was insignificantly higher in controls than in multiple sclerosis patients. Patients with a chronic progressive course of multiple sclerosis had an insignificantly higher mean borrelia antibody level, when compared with those suffering from relapsing/remitting form of disease.

Adolescent↗

Characterization and purification of the F17 adhesin on the surface of bovine enteropathogenic and septicemic Escherichia coli.

The F17 antigen from bovine enterotoxigenic Escherichia coli strain (E coli 25KHO9), which adhered to calf intestinal villi, was isolated. An enterotoxin-negative derivative (25KHO9st) was used for further studies. Using an immunogold-labeling technique, the F17 antigen was characterized as a fimbrial protein. Pure fimbriae with a subunit molecular weight of 20,000 were obtained by homogenization and use of a sucrose gradient. The adhesion of E coli 25KHO9st was mediated by the F17 fimbriae, as both F17 antibodies and F17 protein blocked the adhesion of the strain 25KHO9st. The F17 fimbriae were serologically distinct from K88, K99, F41, and 987P fimbriae and did not agglutinate bovine, ovine, guinea pig, human, or chicken erythrocytes. Peptide fingerprint analysis revealed F17 and F(Y) adhesins to be homologous, if not identical.

Adhesins, Escherichia coli↗