Biomedical subjects

F Masani

Publications and source records attributed to F Masani.

23 records · Page 2Linked to original sources

PubMed1989

[An ultrastructural study of arrhythmogenic right ventricular dysplasia: comparison among islands of myocytes, marginal zone and control zone].

During surgery for intractable ventricular tachycardia, an ultrastructure of cardiac tissue was obtained from two male patients, 54 and 59 years old. On light microscopy, the histopathology was compatible with arrhythmogenic right ventricular dysplasia (ARVD). These myocardial samples were divided into three parts: an island of myocytes (some grouped cardiocytes floating on the fatty layer), a marginal zone (the parts of the myocardium surrounding the fatty infiltration), and a distant zone (as a control muscle). In the island of myocytes and marginal zone, myocardial hypertrophy, variability of cell diameter, degenerative changes of myocytes and interstitial fibrosis were more distinct than in the control zone. In addition, the number and diameter of intrasarcoplasmic lipid droplets detected among interstices of myofibrils also increased in both groups. The variability in number and diameter of the lipid droplets seemed to have a relation to the pathogenesis of fatty infiltration into the myocardium in ARVD. Lipid droplets were also revealed not only in the nuclei of myocytes but in the endothelial cells of capillaries and small vessels. Internuclear inclusion of the lipid was limited to the island and margin, but the lipid droplets in the endothelium spread widely in every zone. These lipid droplets are expected to have diagnostic value in the histological study of ARVD using endomyocardial biopsy.

Arrhythmias, Cardiac↗

PubMed1988

[Myocardial involvement in female Fabry's disease: evaluation by thallium-201 myocardial scintigraphy].

Fabry's disease is characterized by an inherited X-linked disorder of glycosphingolipid catabolism, and heterozygous women affected with this disease who show overt symptoms including cardiac manifestations have rarely been reported. To elucidate the features of myocardial involvement in female patients, noninvasive techniques including exercise stress thallium-201 myocardial scintigraphy were performed. Three female patients, Cases 1-3, 26, 29 and 50 years of age, were documented low leucocytic alpha-galactosidase activities of less than 48% of normal (67.92-16.2 nmol/mg protein/h). They were examined using ECG, two-dimensional echocardiography (2-D Echo), Holter ECG, treadmill test and stress scintigraphy. On the ECG, negative T waves were shown in leads III and aVF in Cases 1 and 2. Left ventricular high voltage, giant negative T waves and short PR intervals were seen in Case 3. The 2-D Echo revealed neither valvular change nor left ventricular hypertrophy. On the Holter ECG, monofocal ventricular premature beats were occasionally observed in Cases 1 and 3. The treadmill test showed positive ST changes only in Case 2. On the exercise stress scintigraphy, uptake of thallium-201 was enhanced in the apex of the heart in Cases 2 and 3. Low uptake areas of thallium-201 were observed in Case 3. The ventricular angiogram revealed slight hypertrophy of the wall of the apical portion. In endocardial biopsies from the right ventricle, myelinoid lamellar inclusions were demonstrated in myocardial cells electron microscopically. Increased uptake of thallium-201 in the apex was noted in two of the three patients, but no apical thickening was noticed in any of the three cases by 2-D Echo. From the result of the biopsy of Case 3, the increased apical uptake of thallium-201 seems to reflect thickening caused by the deposition of glycosphingolipid. It was concluded that myocardial involvement in female Fabry's disease may occur early in the third decade and that the lesions could be detected with high sensitivity by thallium-201 myocardial scintigraphy.

Adult↗

PubMed1986

Immunohistochemical demonstration of S-100 protein in fibroblast-like cells of the guinea-pig heart.

The immunocytochemical localization of S-100 protein was examined in the hearts of adult guinea-pigs. In addition to Schwann cells, adipose cells and chondrocytes, fibroblast-like cells densely distributed in the cardiac skeleton, all of the four valves and tendinous chordae were immunoreactive for S-100 protein. The S-100-positive fibroblast-like cells were conspicuously rounded in shape and extended their thin, thread-like cell processes in opposite directions; the cytoplasm was restricted to perinuclear region. In these morphological features, the cells were distinctly different from ordinary fibroblasts which were immunonegative for S-100 protein. Electron microscopic observation revealed that the S-100-like immunoreactivity was distributed throughout the cytoplasmic matrix in the cell body and processes, but absent from the nuclei and cell organelles. The significance of the S-100 immunopositive fibroblast-like cells was discussed in relation to cartilaginous tissues, which have the potential to form in the region of the cardiac skeleton and valves under both normal and abnormal conditions.

Animals↗

PubMed1986

Node-like cells in the myocardial layer of the pulmonary vein of rats: an ultrastructural study.

The myocardial layer of the pulmonary vein of adult rats was examined by electron microscopy. Among ordinary myocardial cells resembling those of the atrial myocardium, clear cells with structural features similar to those of sinus node cells were identified. They were distributed in the intrapulmonary, preterminal portion of the pulmonary vein. They appeared singly or in small groups among the ordinary myocardial cells. Their cytoplasm was characterised by a paucity of myofilaments, irregular disposition of myofilament bundles, small and oval mitochondria, absence of atrial specific granules and a wide cytoplasmic matrix between intracellular organelles. The intercalated discs of node-like cells were composed of small junctional specialisations. Nerve fibres containing small and large vesicles with and without dense cores were juxtaposed to the node-like cells over an intercellular space of more than 200 nm. Taking into consideration physiological data, the possibility is discussed that the node-like cells may have a potential pacemaking activity and represent an ectopic pacemaker centre in the pulmonary vein.

Actin Cytoskeleton↗

PubMedDate not supplied

Ethanol ingestion on allylamine-induced experimental subendocardial fibrosis.

Effects of ethanol ingestion on allylamine-induced subendocardial fibrosis of the myocardium and intimal hyperplasia of the intramyocardial coronary artery were investigated in male Wistar rats. The toxic effect of allylamine is ascribed to acrolein produced from allylamine by benzylamine oxidase. Animals were forced to drink allylamine solution for 12 weeks. Incidence and size of subendocardial fibrosis were examined, and the lesions of the intramyocardial artery were scrutinized. Effects of ethanol on the systemic blood pressure and benzylamine oxidase activity were investigated in another experiment. Treatment with allylamine resulted in subendocardial fibrosis (size = 4.2%) in 4 of 12 rats. The incidence of fibrosis was increased (up to 6/12) and the area of fibrosis was augmented (to 6.8%) in animals additionally treated with epinephrine. The lesions in the intramyocardial vasculature were also augmented. Ethanol ingestion reduced allylamine-induced subendocardial fibrosis and intramyocardial coronary lesions. The effects were significant in animals additionally treated with epinephrine. Systemic blood pressure and benzylamine oxidase activity were not significantly affected by allylamine or by ethanol. The vasodilatory effect of ethanol may have prevented the development of microvascular spasm induced by allylamine.

Alcohol Drinking↗