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Biomedical subjects

M Arata

Publications and source records attributed to M Arata.

At least 19 recordsLinked to original sources
PubMed1995

Insulin secretion by pancreas of athymic mice injected with peripheral mononuclear cells from insulin-dependent diabetic patients.

We studied the effect of peripheral blood mononuclear cells (PBMNC) from insulin-dependent diabetic (IDDM) children on the insulin secretion pattern of the pancreas from recipient athymic mice. PBMNC from healthy controls or IDDM patients in different stages of disease were injected into athymic mice. PBMNC from newly diagnosed IDDM children elicited basal nonfasting hyperglycemia and in vitro inhibition of the first and second phases of glucose-stimulated insulin secretion in recipient mice. Animals injected with cells from chronically IDDM children showed normoglycemia, abnormal tolerance to glucose, and inhibition of first-phase insulin secretion. Mitomycin C treatment of MNC from IDDM patients abolished insulin secretion inhibition in recipient mice. PBMNC from newly diagnosed and chronically IDDM patients showed positive anti-beta-cell cellular immune aggression. Mice injected with cells from patients during the remission period showed normoglycemia and no alteration of insulin secretion patterns. When relapsed to their former clinical stage, injection of the cells significantly inhibited first-phase glucose-induced insulin secretion in recipients. PBMNC from newly diagnosed IDDM patients were found to migrate to the pancreas of recipient mice preferably as compared with cells from controls. Cells from chronically IDDM patients cultured with concanavalin A (Con A) increased insulin secretion inhibition; despite this, cells from children during the remission period cultured with Con A failed to modify insulin secretion in recipients. These results show that injection of PBMNC from diabetic patients leads to insulin secretion impairment in recipient mice pancreas, and provide a basis for the study of mechanisms involved in the onset and modulation of anti-beta-cell cellular immune aggression induced by human PBMNC.

Adolescent↗
PubMed1992

Comparison of two new immobilization collars.

STUDY OBJECTIVE: To evaluate the limitation of movement of four cervical collars, with emphasis on two new extrication collars. DESIGN: Ranges of motion permitted by four extrication collars, measured by two goniometric techniques, were compared. Times required to apply each collar were noted and compared. SETTING: In a laboratory setting, volunteers were asked to flex, extend, laterally bend, and rotate their necks, first without restriction and then with each of the collars applied. TYPE OF PARTICIPANTS: Participants were healthy volunteers who worked either in the Department of Physical Therapy or in the Emergency Department of Tulane Medical Center Hospital. INTERVENTIONS: The collars used were the Nec-Loc Extrication Collar, Philadelphia Collar, Philadelphia Red EM Collar with Immobilizer, and Vacuum Splint Cervical Collar. MEASUREMENTS: Measurements were performed first using the head goniometer and then the hand-held goniometer. Time required for application was measured in seconds. Statistical evaluation was performed using repeated measure analysis of variance and then Newman-Keuls multiple comparison procedure. MAIN RESULTS: The Vacuum Splint Cervical Collar restricted range of motion of the cervical spine most effectively. CONCLUSION: A cervical collar with design characteristics similar to the Vacuum Splint Cervical Collar (ie, a rigid collar that incorporates part of the thorax) will restrict movement of the neck more effectively than shorter, less rigid collars.

Adult↗
PubMed1992

Rhabdomyosarcoma with focal cartilaginous differentiation (malignant mesenchymoma) of the inferior vena cava.

A sarcoma arising from the inferior vena cava occupied the entire lumen of the inferior vena cava, right atrium, hepatic veins and common iliac veins. Its histological appearance was non-specific sarcoma, except for the presence of a few rhabdomyoblasts and some immature cartilaginous tissue. Immunohistochemically, some tumor cells were positive for myoglobin, desmin, HHF-35, and vimentin. Electron microscopy revealed that some tumor cells contained myofilaments and Z bands in the cytoplasm, which are characteristics of rhabdomyosarcoma. The tumor was diagnosed as rhabdomyosarcoma with focal cartilaginous differentiation (malignant mesenchymoma) of the inferior vena cava.

Aged↗
PubMed1989

Glucagon secretion and alpha-cell sensitivity to somatostatin in genetically diabetic mice C57BL/KsJ-mdb.

In previous studies in C57BL/KsJ mdb/mdb mice, we observed alterations in glucose-induced insulin secretion in vitro, and a defective inhibitory effect of somatostatin on insulin secretion. In this work we studied glucagon secretion patterns under arginine-glucose stimulation, in perifused pancreatic slices from genetically diabetic mice aged 20 to 90 days. We also explored whether alpha-cells present a diminished sensitivity to somatostatin. Results showed that: a) in mdb/mdb mice aged 20 to 90 days, glucagon secretion patterns exhibited basal hypersecretion and a diminished first peak; b) somatostatin inhibited stimulated-glucagon secretion below baseline values in mdb/mdb mice aged 20 to 30 days. In later stages (40 to 90 days), somatostatin exerted a lower inhibitory effect since glucagon levels remain above basal values. This could indicate a progressive impairment in alpha-cell sensitivity to somatostatin, as it was previously observed in beta-cells.

Age Factors↗
PubMed1988

First phase of insulin secretion stimulated by glucose plus theophylline and inhibitory effect of somatostatin in genetically diabetic mice (C57BL/KsJ-mdb).

In a previous study in C57BL/KsJ mdb/mdb mice aged 4 to 12 days we observed a diminished first phase of glucose-induced insulin secretion in vitro, and alterations in the inhibitory effect of somatostatin on insulin secretion. This study explores, using perifused pancreatic slices, whether the reduced B-cell responsiveness to somatostatin in mdb/mdb mice can be overcome upon induction of a biphasic insulin release by using theophylline. Under these conditions our results show: (1) in mdb/mdb mice aged 4 to 6 days, the restoration of the first peak of insulin secretion overcomes the reduced B-cell sensitivity to somatostatin; and (2) in mdb/mdb mice aged 7 to 12 days, the addition of theophylline only causes a partial restoration of B-cell responsiveness to somatostatin, suggesting that other mechanisms could be involved in the progressive impairement of B-cell sensitivity to somatostatin inhibitory effect.

Aging↗
PubMed1986

Secretion and effect of somatostatin in early stages of the diabetic syndrome in C57BL/KsJ-mdb mice.

In a previous study in C57BL/KsJ (mdb) mice aged 12 to 90 days, we observed alterations in the secretion of insulin and somatostatin and in the inhibitory effect of the latter upon insulin secretion. This study explores whether hormonal alterations are to be found in the very early stages of the diabetic syndrome, i.e. between ages 4 and 12 days. The results demonstrate two distinct phases in the development of the syndrome: up to age 6 days, the perifused slices of pancreata of control animals present biphasic glucose-induced patterns of insulin and somatostatin secretion, whereas the diabetic animals show a diminished first peak of insulin secretion, but a similar pattern of somatostatin secretion, to that of the control animals; between ages 7 and 12 days, the pancreata of diabetic mice exhibit insulin hypersecretion in basal conditions, and an absence of the first secretion peak and insulin hypersecretion in the second phase in response to glucose stimulation. The glucose-induced pattern of somatostatin secretion presents hormonal hypersecretion in both phases. B-cell sensitivity to the inhibitory effect of somatostatin is diminished in mdb mice of the above-mentioned groups, an alteration which becomes more evident as diabetes evolves. The results show that, in very early stages of the evolution of the diabetic syndrome in C57BL/KsJ (mdb) mice, there are already alterations in insulin and somatostatin secretion patterns and in the inhibitory effect of the latter on insulin secretion.

Age Factors↗