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Biomedical subjects

M Fink

Publications and source records attributed to M Fink.

At least 199 records · Page 11Linked to original sources
PubMed1990

[Diabetes mellitus and breast cancer. A retrospective follow-up study].

The influence of diabetes mellitus on the course of breast cancer was investigated retrospectively in 752 patients. Possible unfavourable prognostic factors like overweight, lipid disorders, age and menopausal status were considered as confounders in a Cochran-Mantel-Haensel analysis. There was no difference in primary tumor status and lymph node involvement between patients with diabetes mellitus and nondiabetic patients. Diabetic patients had more often overweight, lipid disorders and were older than nondiabetic patients. Metastatic disease was highly significant correlated with primary tumor status (p less than 10(-6)) lymph node involvement (p less than 10(-10)) and diabetes mellitus (p less than 10(-5)). Overweight, lipid disorders, age and menopausal status were not correlated with metastatic disease. A possible explanation of the correlation between diabetes mellitus and metastatic disease could be hyperinsulinism in type IIB diabetes. A type IIB diabetes in most of the patients included in this study is very plausible because of the correlation between overweight, lipid disorders, old age and diabetes mellitus. This type of diabetes is characterised by a relative resistence to insulin in the target tissues and a prolonged and exceeding insulin secretion. Experimental data demonstrate that insulin stimulates the growth of breast cancer cell in vivo and in vitro.

Adult↗
PubMed1990

Partially coherent transducers: the random phase transducer approach.

Ultrasound speckle is a consequence of the stochastic nature of the reflectivity of scattering media (e.g., biological tissue) and of the coherent nature of piezoelectric transducers. This speckle noise can be reduced by the use of incoherent processing techniques (e.g., spatial compounding, incoherent summation, random phase and phase insensitive transducers). We present a unified framework that explains the limitations of incoherent processing in terms of the information grain theory. This theory predicts the gains in SNR as well as the losses in directivity. We also present the random phase transducer approach to incoherence to total coherence. We present applications to speckle reduction, detection of specular reflectors, attenuation estimation and ultrasound imaging. We show that totally incoherent transducers completely remove diffraction effects. They might be used in attenuation estimation, in which case, correction for diffraction is no longer required, in order to obtain unbiased estimates. Partially coherent transducers might also be useful in imaging to reduce speckle noise.

Humans↗
PubMed1990

Infrared optical fibers for surgical applications.

The basic characteristics of fibers that are appropriate for surgical use in the infrared are reviewed. New fiber materials, such as sapphire, fluorozirconate and chalcogenide glasses, and polycrystalline fibers are discussed as well as their applicability for surgical procedures.

Equipment Design↗
PubMed1990

How does convulsive therapy work?

There is no death of hypotheses to explain the antidepressant action of convulsive therapy. Neurohumoral-receptor, kindling-anticonvulsant, and neuroendocrine ideas are prominently discussed. Views based on direct comparisons with antidepressant drugs or based on pharmacologic models are seen as inadequate. The neuroendocrine hypothesis, derived from human studies, appears the most viable. It argues that the affective disorders result from a deficiency of a mood-modifying peptide (antidepressin) derived from the hypothalamus. Convulsive therapy stimulates the production and release of antidepressin. Studies dedicated to the search for this peptide as a replacement for ECT are encouraged.

Adrenocorticotropic Hormone↗
PubMed1989

Multiple brown tumors in a patient with nutritional secondary hyperparathyroidism.

For years, brown tumors have been considered to be a characteristic of primary hyperparathyroidism. However, since 1963 several reports indicate the incidence of brown tumors in patients with renal secondary hyperparathyroidism to be 1.5%-1.7%. The appearance of multiple brown tumor lesions is rather uncommon in secondary hyperparathyroidism which is also true for malabsorption as its cause. We report on a 56-year-old man presenting with pain in the bones and multiple osteolyses. A bone biopsy specimen and the laboratory examinations were indicative of secondary hyperparathyroidism caused by malabsorption most likely due to Billroth's II/I gastric resection. Thus, the patient's osteolyses represent brown tumors which have been induced by nutritional secondary hyperparathyroidism.

Bone Neoplasms↗
PubMed1988

Mechanisms of altered monocyte prostaglandin E2 production in severely injured patients.

Monocytes from immunosuppressed trauma (11 patients) and burn (12 patients) patients stimulated with muramyl dipeptide, a potent prostaglandin E2 (PGE2) secretagogue, showed twofold greater PGE2 production compared with normal controls or immunocompetent patients. Monocyte plasminogen activator production was markedly depressed and inversely correlated to patients' monocyte hyper PGE2 production. Levels of the PGE2-producing monocyte subset (selected as high-affinity Fc+ receptors) were progressively elevated after injury in immunosuppressed patients, reaching 65% to 80% of the total monocyte population (39% for normal controls). Although early T-suppressor (Ts) lymphocytes did not augment monocyte PGE2 secretion, Ts lymphocytes that appeared late (greater than 12 days after injury), during chronic infection, acted as monocyte PGE2 secretagogues. Posttraumatic increases in monocyte sensitivity to PGE2 secretagogues augmented the numbers of PGE2-secreting monocytes, and the appearance of Ts lymphocytes with PGE2 secretagogue activity may be responsible for elevated monocyte PGE2 production in immunosuppressed trauma patients.

Adult↗