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Biomedical subjects

R Levy

Publications and source records attributed to R Levy.

At least 343 records · Page 19Linked to original sources
PubMed1994

Mycoplasma and Chlamydia in adenoids and tonsils of children undergoing adenoidectomy or tonsillectomy.

The prevalence of mycoplasmal and chlamydial infection was assessed in 83 children undergoing adenoidectomy, tonsillectomy, or both procedures for recurrent adenotonsillitis or obstructive symptoms. Throat smears (surface specimens) and minced adenoids and tonsils (core specimens) were cultured for Mycoplasma spp and for Chlamydia spp. Isolation rates in adenoidal specimens were as follows: Mycoplasma hominis, surface 7.1% core 2.9%; and Ureaplasma urealyticum, surface 1.4%, core 2.9%. Mycoplasma hominis was also found in tonsillar specimens: surface 14.3%, core 20%. Chlamydia trachomatis was isolated only from a single core adenoidal specimen. The rate of mycoplasma isolation was significantly higher in children with recurrent adenotonsillitis (34.5%) than in those with obstructive symptoms (3.7%). Our findings document colonization of genital mycoplasmas in adenoids and tonsils of children with recurrent adenotonsillitis. Further studies are needed to evaluate the possible pathogenetic role of these microorganisms in adenotonsillar infection.

Adenoidectomy↗
PubMed1994

Neuropathological correlates of psychotic phenomena in confirmed Alzheimer's disease.

BACKGROUND: The prevalence of psychotic phenomena in confirmed Alzheimer's disease (AD) and their potential neuropathological correlates have rarely been the subject of prospective investigation. METHOD: Psychopathological disturbances were recorded prospectively according to the Geriatric Mental State Schedule and the CAMDEX: The frequency of these phenomena and neuropathological changes were examined in 56 patients with definite AD. RESULTS: Hallucinations had been documented in 13 patients, paranoid delusions in 9 and delusional misidentification (e.g. the Capgras-type and the 'phantom boarder' symptoms) in 14 patients. Misidentifications were associated with lower neurone counts in the area CA1 of the hippocampus. Delusions and hallucinations were observed in patients with less severe cell loss in the parahippocampal gyrus and with lower cell counts in the dorsal raphe nucleus. A decrease of neurones in the locus coeruleus in a subset of depressed patients with AD had been reported earlier. Delusions and delusional misidentification were common in 5 patients with basal ganglia mineralisation, but there was no statistically significant association of these symptoms with the presence of Lewy bodies in the brainstem and neocortex of our patient sample. CONCLUSIONS: These findings are compatible with the view that morphological changes in certain brain areas may promote the development of psychotic phenomena in AD. AD may offer a model for the understanding of pathomechanisms underlying the development of psychopathological disturbances in other psychoses with more discrete neuropathological changes.

Aged↗
PubMed1994

Quantitative magnetic resonance imaging volumetry distinguishes delusional disorder from late-onset schizophrenia.

BACKGROUND: Late paraphrenia is recognised as a heterogeneous disorder. This is reflected by the division of such patients into schizophrenia and delusional disorder in ICD-10. Earlier imaging studies have suggested that major structural abnormalities may be associated with the onset of psychosis in later life. METHOD: Fifty late paraphrenics and 35 age-matched healthy controls underwent structural magnetic resonance imaging of the whole brain in the coronal plane. Measurements were made of intracranial and brain volumes and the volumes of the intracerebral and extracerebral cerebrospinal fluid spaces. RESULTS: No differences in intracranial, brain or extracerebral cerebrospinal fluid volumes between patients and controls were found. Late paraphrenic patients had greater lateral and third ventricle volumes than controls and the left lateral ventricle was larger than the right. When the patients were divided into appropriate ICD-10 diagnoses: paranoid schizophrenia (n = 31) and delusional disorder (n = 16), lateral ventricle volumes in the delusional disorder patients were much greater than those of the schizophrenics and almost twice those of controls. CONCLUSIONS: Structural brain differences underly diagnostic heterogeneity within late paraphrenia. The brains of late onset schizophrenics are only subtly different from those of healthy elderly individuals.

Age of Onset↗
PubMed1994

Opioids inhibit endothelin-mediated DNA synthesis, phosphoinositide turnover, and Ca2+ mobilization in rat C6 glioma cells.

Opioid agonists inhibit DNA synthesis in C6 rat glioma cells that express opioid receptors, induced by desipramine (DMI). This inhibition was not observed in cells that were not treated with DMI, and thus did not express opioid-binding sites. Endothelin, a known mitogen, increased thymidine incorporation dose dependently (up to 1.7-fold) in DMI-treated C6 cells. This increase was reversed by an anti-idiotypic antibody to opioid receptors, Ab2AOR, which has opioid agonist properties. The opioid antagonist naltrexone blocked the inhibition caused by Ab2AOR. Endothelin also stimulated phosphoinositide (PI) turnover and this effect was inhibited by morphine (50%) or by Ab2AOR (72%) in DMI-treated but not in DMI-untreated C6 cells. These actions of morphine and Ab2AOR were reversed by naltrexone. The inhibition of PI turnover and of thymidine incorporation by Ab2AOR or morphine was insensitive to pertussis toxin (PTX). Since PI turnover is known to induce Ca2+ mobilization, it was of interest to examine the effects of the applied opioids on intracellular Ca2+ concentrations. Endothelin increased the concentration of cytosolic free Ca2+ in the cells while Ab2AOR, morphine, and beta-endorphin reversed the endothelin-induced Ca2+ mobilization in DMI-treated but not in DMI-untreated C6 cells. The effect of these agonists was also blocked by naltrexone. The results indicate that glial cells can be a target of an opioid receptor-mediated antimitogenic action and that an abatement in PI turnover and Ca2+ mobilization may be associated with this mechanism.

Animals↗
PubMed1994

Serum thyroglobulin and iodine-131 whole-body scan in the diagnosis and assessment of treatment for metastatic differentiated thyroid carcinoma.

UNLABELLED: Because of the limitations of periodic 131I whole-body scans, including suspension of substitution therapy, questionable sensitivity and low yield in detecting metastases in patients who have undergone thyroidectomy, serum thyroglobulin and 131I whole-body scans were evaluated for sensitivity in detecting local, regional or distant metastases in 261 patients with differentiated thyroid carcinoma after total thyroidectomy and ablation. METHODS: A noncompetitive immunoradiometric assay was used for serum thyroglobulin determination. An 131I whole-body scan was obtained after replacement therapy had been suspended for 6 wk or when TSH reached levels higher than 50 microU/ml. In patients who underwent radiological procedures with iodinated contrast media, the waiting period before the 131I whole-body scan was no less than 10 wk. RESULTS: Of the 58 patients with proven metastases who were followed for 12 yr (mean 7 +/- 3.3 yr), 51 (88.4%) had high serum thyroglobulin assays performed while under full replacement therapy and 32 (55%) showed clear 131I whole-body scan localization. There were no instances of positive whole-body scans and negative serum thyroglobulin. CONCLUSION: In patients treated with 131I, serum thyroglobulin assay was an excellent method to assess treatment. Patients with metastatic disease and negative whole-body scans with or without serum thyroglobulin exhibited a trend toward higher mortality. This trend may also indicate that the lack of 131I trapping and low thyroglobulin is a sign of metabolic dedifferentiation of otherwise histologically differentiated thyroid tumors.

Adenocarcinoma, Follicular↗
PubMed1993

Modulation of thymidine incorporation by kappa-opioid ligands in rat spinal cord-dorsal root ganglion co-cultures.

beta-Endorphin, met-enkephalin and several mu-selective opioid agonists were shown to decrease thymidine incorporation into DNA in various neural cell cultures. We now report that the kappa-selective opioid agonists U50488, U69593 and MR2034 modulate [3H]thymidine incorporation into DNA in rat spinal cord-dorsal root ganglion co-cultures. U50488 at 10 microM increased by 60% thymidine incorporation in 6-day-old cultures. The thymidine incorporation induced by U50488 was blocked by the kappa-selective antagonist nor-binaltorphimine, as well as by pertussis toxin and LiCl. U50488 treatment stimulated phosphatidylinositol turnover by three-fold compared with untreated controls. These findings suggest that kappa-opioid agonists modulate DNA synthesis in spinal cord-dorsal root ganglion co-cultures through a mechanism which involves pertussis toxin-sensitive GTP-binding proteins, as well as activation of phosphatidylinositol turnover.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

Expression of endothelin-1 in the lungs of patients with pulmonary hypertension.

BACKGROUND: Pulmonary hypertension is characterized by an increase in vascular tone or an abnormal proliferation of muscle cells in the walls of small pulmonary arteries. Endothelin-1 is a potent endothelium-derived vasoconstrictor peptide with important mitogenic properties. It has therefore been suggested that endothelin-1 may contribute to increases in pulmonary arterial tone or smooth-muscle proliferation in patients with pulmonary hypertension. We studied the sites and magnitude of endothelin-1 production in the lungs of patients with various causes of pulmonary hypertension. METHODS: We studied the distribution of endothelin-1-like immunoreactivity (by immunocytochemical analysis) and endothelin-1 messenger RNA (by in situ hybridization) in lung specimens from 15 control subjects, 11 patients with plexogenic pulmonary arteriopathy (grades 4 through 6), and 17 patients with secondary pulmonary hypertension and pulmonary arteriopathy of grades 1 through 3. RESULTS: In the controls, endothelin-1-like immunoreactivity was rarely seen in vascular endothelial cells. In the patients with pulmonary hypertension, endothelin-1-like immunoreactivity was abundant, predominantly in endothelial cells of pulmonary arteries with medial thickening and intimal fibrosis. Likewise, endothelin-1 messenger RNA was increased in the patients with pulmonary hypertension and was expressed primarily at sites of endothelin-1-like immunoreactivity. There was a strong correlation between the intensity of endothelin-1-like immunoreactivity and pulmonary vascular resistance in the patients with plexogenic pulmonary arteriopathy, but not in those with secondary pulmonary hypertension. CONCLUSIONS: Pulmonary hypertension is associated with the increased expression of endothelin-1 in vascular endothelial cells, suggesting that the local production of endothelin-1 may contribute to the vascular abnormalities associated with this disorder.

Adult↗
PubMed1993

Idiotype/granulocyte-macrophage colony-stimulating factor fusion protein as a vaccine for B-cell lymphoma.

To produce a vaccine against cancer, antigens must be found that are preferentially expressed by tumour cells and can induce an immune response against the tumour. The variable regions of the immunoglobulin molecules expressed on malignant B cells (idiotypes) are tumour-specific, but are weak immunogens. To induce an immune response in animals or humans, the idiotypic protein has therefore to be chemically coupled to a strongly immunogenic protein and mixed with an adjuvant. The resulting response can protect animals from subsequent tumour challenge, and cure animals with established tumours in combination with chemotherapy. Granulocyte-macrophage colony-stimulating factor (GM-CSF) augments antigen presentation in a variety of cells. Here we show that by fusing a tumour-derived idiotype to GM-CSF, it can be converted into a strong immunogen capable of inducing idiotype-specific antibodies without other carrier proteins or adjuvants and of protecting recipient animals from challenge with an otherwise lethal dose of tumour cells. This approach may be applicable to the design of vaccines for a variety of other diseases.

Animals↗