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Biomedical subjects

S Handa

Publications and source records attributed to S Handa.

446 records · Page 25Linked to original sources
PubMedDate not supplied

Variations in myocardial contraction sequence under various hypoxic conditions.

Hypokinetic myocardial segment motion is observed in various pathophysiologic conditions. The aim of this study was to clarify the mechanisms involved in differences in segment motion of hypokinesis. Nineteen open-chest dogs were studied with regard to myocardial segment length, left ventricular pressure, and internal minor-axis diameter. Sequential instantaneous myocardial elastance [alpha(t) curve] was calculated under 4 different hypoxic conditions: complete coronary occlusion and reperfusion, partial coronary occlusion, coronary microembolization, and anoxic perfusion. The alpha(t) curve peaked at end-systole in the case of normal contraction; but it was almost totally flat when complete bulging occurred. The hypokinesis which occurred during development of the complete systolic bulge immediately after complete coronary occlusion had an earlier alpha(t) peak curve than the hypokinesis resulting from partial coronary stenosis (209.5 +/- 35.6 ms after end-diastole vs. 261.9 +/- 18.2 ms; p less than 0.02), microsphere injection into the coronary artery (243.2 +/- 24.5 ms vs. 289.3 +/- 15.4 ms; p less than 0.05), or anoxic perfusion (213.4 +/- 40.2 vs. 275.6 +/- 28.3 ms; p less than 0.05). The early alpha(t) peak resulted in a late-systolic bulge in segment length motion. In conclusion, hypokinetic segment motion differed depending on whether the coronary blood flow was present or not. A late-systolic bulge only developed immediately after complete coronary occlusion, and resulted from an abrupt decrease in myocardial stiffness during the cardiac cycle, which is closely related to the abrupt cessation of coronary blood flow.

Animals↗
PubMedDate not supplied

Linear hypopigmentation after triamcinolone injection: a rare complication of a common procedure.

The development of linear hypopigmentation after intralesional or intraarticular injection of triamcinolone acetonide has been reported in the literature as a very rare side effect. This case report describes a patient with linear hypopigmentation and discusses the possible pathophysiology. Clinicians involved in the care of hypertrophic scars and keloids need to be aware of this rare side effect so that they can guide their patients appropriately. They need to understand the pathogenesis of this complication better so that it may become avoidable.

Anti-Inflammatory Agents↗
PubMedDate not supplied

Bilateral en coup de sabre-a rare entity.

Linear scleroderma involving the frontal or frontoparietal region of the scalp (with or without associated facial hemiatrophy) is called "en coup de sabre" (like the stroke of a sabre). We report a case which to the best of our knowledge is only the fifth instance of this subset of localized morphea occurring in a bilateral distribution. We believe that the rarity of this presentation warrants a report.

Child, Preschool↗
PubMedDate not supplied

Tuberous sclerosis with macrodactyly.

Tuberous sclerosis with macrodactyly is a very uncommon presentation. We report a 15-year-old girl with a thick, loose hyperpigmented area on the dorsum of the left hand with macrodactyly. A skin biopsy specimen from the dorsum of the left hand revealed dense collagenization in the dermis. Radiographs showed marked irregular thickening of the cortex of the metacarpals and phalanges of the left index and middle fingers.

Adolescent↗
PubMedDate not supplied

Spinal dysraphism presenting as acro-osteolysis: report of four cases.

The acro-osteolyses are a heterogeneous group of disorders characterized by bone resorption. The disorder may occur as familial, idiopathic, or secondary to vascular, inflammatory, or neurologic conditions. Acro-osteolysis is rare in association with spinal dysraphism. It is even rarer for it to be the presenting symptom in spinal dysraphism. We report here four patients in whom the diagnosis of spinal dysraphism was established while investigating for the various causes of acro-osteolysis. All four patients presented with trophic changes and acro-osteolysis. Hyperhidrosis in the affected limb was seen in three patients. One patient had leg pain, the others had no sensory or motor deficits. Magnetic resonance imaging showed spinal dysraphism in all four patients.

Adolescent↗
PubMedDate not supplied

Beta-blockade prevents ventricular failure following aortic regurgitation in rabbits.

This study investigated the effects of chronic beta-blockade on the pathophysiology of heart failure following induction of aortic regurgitation (AR). Nine rabbits with AR were administered propranolol continuously for 7 days (AR+P), 8 rabbits with AR received vehicle for the same period (AR+C), and 7 rabbits underwent sham operation. Cardiac output was lower and the left-ventricular end-diastolic pressure was higher in AR+C than in sham-operated rabbits, but there was no difference in the right-ventricular end-diastolic pressure between the two groups. Down-regulation of beta-adrenoceptors was observed in the left ventricle, but not in the right ventricle. All of these variables were reversed in AR+P. In left-ventricular failure produced by AR, (1) the augmentation of adrenergic drive occurred selectively in the left ventricle, and (2) propranolol blunted adrenergic drive and played a protective role against myocardial damage.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Multiple primary left ventricular myxomas with multiple intraventricular recurrences.

A 23-year-old male was operated on for two primary left ventricular myxomas of the "complex" type. Ten months later, abnormal echo reappeared and reoperation was carried out to excise 2 recurrent myxomas in the left ventricle. Multiple foci were most likely responsible for the recurrence. No recurrence has been detected for 20 months postoperatively. This may be the first reported case of multiple primary left ventricular myxoma with multiple recurrences in the left ventricular cavity.

Adult↗
PubMedDate not supplied

[Low concentrations of epinephrine can augment shear stress-induced platelet aggregation].

Platelet aggregation induced by shear stress is distinct from that induced by an agonist such as ADP or collagen. The physiological significance of shear-induced platelet aggregation was investigated by measuring the effects of the presence of physiological concentrations of epinephrine. Blood samples were taken from 10 normal volunteers who had received no drugs known to interfere with platelet functions for 1 month preceding the study. Blood was mixed with 1/10 volume of 3.1% sodium citrate solution. Platelet-rich plasma and platelet-poor plasma were prepared by centrifugation at 100 g for 15 min and 2,000 g for 15 min, respectively. The platelet count of platelet-rich plasma was adjusted to 3 x 10(5)/microliters. Shear-induced platelet aggregation in platelet-rich plasma was determined using a modified cone and plate viscometer controlled by a personal computer system. The intensity of light transmission was continuously recorded. The percent platelet aggregation was calculated according to the Lambert-Beer equation. Platelet aggregation occurred under both low (12 dyn/cm2) and high (108 dyn/cm2) shear stress. More significant aggregation was observed under high shear stress. The maximum percent platelet aggregation was 44.7 +/- 13.4%, which increased to 53.3 +/- 10.0% in the presence of 10 pg/ml epinephrine. With 100 pg/ml of epinephrine, shear-induced platelet aggregation induced by 12 dyn/cm2 shear significantly increased, but the effects on shear-induced platelet aggregation of 108 dyn/cm2 shear were not uniform. Shear-induced platelet aggregation is enhanced by physiological concentrations of epinephrine, which may be a cause of arterial thrombotic occlusion in sympathomimetic states.

Adult↗