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Biomedical subjects

O Peters

Publications and source records attributed to O Peters.

At least 37 records · Page 2Linked to original sources
PubMed1994

Monosynaptic excitation of preganglionic vasomotor neurons by subretrofacial neurons of the rostral ventrolateral medulla.

Extracellular single unit recordings were made from barosensitive neurons in the subretrofacial nucleus (SRF) of the rostral ventrolateral medulla in chloralose-anaesthetised cats. At the same time, single preganglionic neuron activity was recorded from filaments of the cervical sympathetic trunk (CST); barosensitive units were selected for study. Evidence for monosynaptic connections between the two neuron groups was sought by cross-correlation analysis of their ongoing activity. Cross-correlograms of 16/16 SRF/CST neuron pairs showed a broad peak (100-200ms wide), reflecting the synchronizing action of arterial baroreceptors on both neurons' activity. Two of the 16 cross-correlograms additionally showed a robust, statistically significant, narrow peak of a single 2 ms bin width, providing the first physiological demonstration that ventrolateral medullary neurons monosynaptically excite preganglionic sympathetic neurons. Deductions are made about the strength, convergence and divergence of the connection.

Animals↗
PubMed1992

Influence of azithromycin and other macrolides on the intracellular killing of Staphylococcus aureus by human polymorphonuclear leucocytes of healthy donors and a patient with Chédiak-Higashi syndrome.

A mixture of human blood phagocytes from healthy donors and opsonized staphylococci was incubated in vitro for 30 min. After that time all the bacteria were phagocytosed. The test tubes were further incubated for 2, 4 and 24 h with or without addition of a macrolide (erythromycin, azithromycin, clarithromycin, roxithromycin) and the effect of these drugs on the survival of intracellular staphylococci (Staphylococcus aureus ATCC 25923) was measured. The minimal effective concentration of the antibiotic which killed 80-90% of the bacteria after a 4-hour incubation was 0.1 mg/l for erythromycin, azithromycin and clarithromycin and 1.2 mg/l for roxithromycin. The percentage of surviving bacteria after 2 and 4 h incubation was not significantly different between these macrolides at the minimal effective concentration. Increasing the concentration of each antibiotic above the minimal effective concentration did not alter the killing rate of intracellular staphylococci. The bacterial activity of polymorphonuclear leucocytes (PMNL) from a patient with Chédiak-Higashi syndrome was less in comparison to PMNL from healthy donors, but was improved in vitro by the addition of erythromycin or azithromycin.

Anti-Bacterial Agents↗
PubMed1989

Evaluation of oesophageal transit in patients with minor peptic oesophagitis.

Fifty-one adult patients with complaints suggesting peptic oesophagitis were submitted within the same week to a radionuclide swallow test (OT), an endoscopy and a manometry in order to evaluate the incidence of oesophageal peristaltic abnormalities in patients with only minor peptic oesophagitis. In all patients with normal endoscopy, OT did not show any transit abnormality. In the patients with slight (Stage I) or moderate (Stage II) oesophagitis, OT was abnormal in 60% of the cases. The results were at least as good as those obtained by means of manometry and suggest that OT is an accurate method for the detection of slight impairment of oesophageal contractility.

Adult↗
PubMed1987

Immunocytochemical and ultrastructural findings in a mature retroperitoneal teratoma.

Report is made of a mature retroperitoneal teratoma in a 32-year-old man. Investigation of the tumor revealed cells immunoreactive for ACTH, Met-enkephalin, beta-LPH, serotonin, FSH, BPP, S100, Neuron-specific-enolase. These cells were mainly present in the glandular epithelium, lining the cysts of the tumor. Ultrastructurally, neuro-secretory granules were demonstrated in the cytoplasm of the tumoral endocrine cells. At no time did the patient display endocrine symptoms.

Adrenocorticotropic Hormone↗
PubMed1987

Pneumomediastinum after self-dilation of the esophagus.

Pneumomediastinum following esophageal perforation is a known complication of Eder Puestow dilation for esophageal stenosis. This is the first reported case of esophageal perforation and pneumomediastinum occurring after instrumental self-dilation of a stenotic esophageal lesion. The observed 0.02 percent perforation rate in this patient (compared to the reported 0.3 percent in Eder Puestow "hetero"-dilation) makes the Eder Puestow auto-dilation procedure seem justifiable in a well-trained and well-informed patient.

Aged↗
PubMed1986

Intraarterial sodium nitroprusside infusion in the treatment of severe ergotism.

Treatment of migraine with ergot alkaloids may produce systemic vasospasm in patients, especially as a result of automedication and overconsumption but also due to individual hypersensitivity. Peripheral vasoconstriction may lead to gangrene of the extremities, necessitating amputation. Various treatments have been tried against ischemic complications during ergotism with varied and unpredictable results. We report two recent cases of severe acute peripheral ischemia due to ergotamine abuse successfully treated with continuous systemic sodium nitroprusside infusion. The doses used during intraarterial injection are well below those known to be toxic. Consequently, the adverse effects of cyanide toxicity can be avoided. We think that intraarterial infusion of sodium nitroprusside, associated with forced diuresis and the administration of hydroxycobalamin, constitutes the treatment of choice of extreme peripheral ischemia of ergotism.

Adult↗
PubMed1986

Periventricular metastases of a primary intracranial alpha-fetoprotein-producing germ cell tumor.

Periventricular subependymal lesions were found on CT scan in a young man with growth failure, diabetes insipidus, mental deterioration, and hypogonadism with delayed puberty. An initial very good response to radiotherapy was followed a few months later by a relapse, presenting as a very large tumor in the base of the frontal lobes. Serum alpha-fetoprotein at the time of the relapse was very elevated suggesting that the tumor was largely composed of an endodermal sinus tumor component, which was confirmed at autopsy. The purpose of this report is to stress the importance of the use of tumor markers in a particular clinical and neuroradiological setting.

Adolescent↗
PubMed1986

Posterior mediastinal sarcoidosis.

We report two cases of enlargement of the posterior mediastinal lymph nodes due to sarcoidosis. Bilateral hilar enlargement, pulmonary parenchymal involvement, or extrathoracic manifestations of sarcoidosis were absent. A diagnostic thoracotomy had to be performed in both instances.

Adult↗
PubMed1986

Aleukemic leukemia cutis. An unusual presentation of acute myelomonocytic leukemia.

A patient with acute myelomonocytic leukemia is reported. He had presented erythroderma and atypical cellular infiltration of the skin 4 months prior to the detection of leukemia in the peripheral blood and bone marrow. Aleukemic leukemia cutis is a rare condition which is characterized by leukemic cells invading the skin prior to the observation of leukemic cells in the peripheral blood. The cases of aleukemic leukemia cutis reported in the literature show little or no conformity in their clinical appearance. Enzyme cytochemistry, immunocytological and electron-microscopic studies are of considerable help in differentiating the cutaneous infiltrates and in establishing early diagnosis. We report herein a patient with erythroderma which regressed spontaneously, whereas microscopic examination of a cutaneous biopsy showed atypical cells infiltrating the dermis. After a period of 3 months, during which the patient remained free of lesions, he showed recurrence of the erythroderma while developing acute myelomonocytic leukemia. We feel this unusual presentation of aleukemic leukemia cutis should be added to the evergrowing list of cutaneous manifestations of leukemia.

Dermatitis, Exfoliative↗
PubMed1984

Intracellular inclusion bodies in 14 patients with B cell lymphoproliferative disorders.

Two types of intracytoplasmic inclusion were detected by immunofluorescence microscopy in 12 patients with chronic lymphocytic leukaemia and two patients with a leukaemic phase of well differentiated lymphocytic lymphoma. Further analysis with light- and electron microscopy, showed that most inclusion bodies were rod-like crystalline structures. However, in three patients they consisted of amorphous vesicular precipitates. Immunological studies revealed the presence of immunoglobulins of the same class and type at the cell surface as well as in the inclusion bodies. The monoclonal immunoglobulins were all of lambda type except in two cases. The origin of immunoglobulin inclusion bodies in B cell malignancies is discussed in relation to published data and our own observation in one patient followed during treatment.

Aged↗