Sequential morphological studies of the esophageal carcinoma of rats induced by N-methyl-N-amylnitrosamine

N-Methyl-N-amylnitrosamine was given to male Wistar rats in the drinking water at a concentration of 0.003% for 8 weeks. Three rats were autopsied weekly from the first to the 25th week. The stages of hyperplasia, dysplasia and squamous cell carcinoma in the esophagus were chronologically observed. Hyperplasia and dysplasia were found by the 6th week and continuously observed until the end of the experiment. Early squamous cell carcinomas were found in the 13th week. They showed endophytic or exophytic growths. Histologically, the endophytic growths were well-differentiated squamous cell carcinomas and the exophytic growths were poorly-differentiated. Advanced carcinomas were first found in the 15th week and were almost well-differentiated. Carcinomas were not found in papillomas. The incidence of carcinomas increased with time, being 9 out of 15 rats (60%) in the final 21st through 25th weeks. Lymph node metastasis was found in one rat, killed at the 24th week.

[Difference of the shortening characteristics between left ventricular endocardium and epicardium as measured by radiopaque markers in experimental dogs]

This study was performed to clarify the difference of shortening characteristics between left ventricular epicardium and endocardium. Four to five pairs of radiopaque markers (lead beads, phi 0.3- 0.8 mm) were implanted just beneath the epicardium and endocardium, respectively in eight open-chest dogs. After the pericardium and thorax were closed, biplane cine-roentgenograms were obtained. The spatial distance (segment length) between any two of the markers was calculated using a digitizer-computer-plotter system. Left ventricular wall thickness (Th) was measured as a distance between epicardial and endocardial markers. The maximum left ventricular thickness (Thmax) was 9.4 +/- 3.4 mm (mean +/- SD), the minimum (THmin) 8.4 +/- 3.1 mm, and a percent increase of wall thickness [(Thmax-Thmin)/Thmin] was 12.7 +/- 6.5%. The value of epicardial segment length divided by endocardial segment length as normalized by each length at R wave of ECG was 1.088 +/- 0.071 at the end of systole and 0.979 +/- 0.016 at end diastole, indicating that endocardial segment shortened and distended more than epicardial segment during systole and diastole, respectively. Epicardial segment began to shorten 3 +/- 26 msec earlier and distend 4 +/- 50 msec earlier than endocardial one. This study revealed a small but consistent difference in the amount of shortening and its initiation and termination between the epicardium and endocardium.

[Effect of nitroglycerin on epicardial and endocardial shortening characteristics in dogs]

In 8 dogs, several paired lead beads as radiopaque markers were implanted in the subepicardial and subendocardial regions, and biplane cineradiograms were obtained after closure of the chest. The spatial distance (segment length) between the two markers in the outer and inner sides of the myocardium was calculated using a digitizer-computer-plotter system, and the effect of nitroglycerin on regional left ventricular geometry was assessed. Segment length at the R wave of the electrocardiogram (LECG R) was reduced from 39.7 +/- 11.8 (mean +/- SD) to 38.8 +/- 12.1 mm at the subepicardium and from 31.9 +/- 9.5 to 29.5 +/- 10.4 mm at the subendocardium 3 minutes after intravenous injection of 0.5 mg of nitroglycerin. Segment length at endsystole (LES) was also reduced from 38.9 +/- 11.7 to 38.2 +/- 11.8 mm at the subepicardium and from 29.6 +/- 9.2 to 27.9 +/- 9.9 mm at the subendocardium by nitroglycerin. Systolic shortening [(LECG R--LES)/LECG R] x 100) showed a slight reduction after nitroglycerin. Left ventricular wall thickness measured as a distance between subepicardial and correspondent subendocardial markers showed a slight but significant increase by nitroglycerin: Maximal thickness was increased from 10.9 +/- 3.2 to 11.4 +/- 3.3 mm, and thickness at the R wave of the electrocardiogram was also increased from 10.9 +/- 3.1 to 10.5 +/- 3.2 mm. Thickening of the wall was markedly increased at the anterior mid portion of the left ventricle but not at the base, suggesting nitroglycerin has larger effect on the former position than the latter.

Retinal vascular patterns in the macula and the perimacular area in premature and full-term infants

27 eyes of 20 premature and full-term infants were subjected to trypsin digestion, and a study was made of the extension of the temporal retinal vessels and of the formation of the radial peripapillary capillaries (RPCs) and the capillary-free zone in the macula. The advancing borders of the temporal retinal vessels exhibited a V-shaped appearance in cases of 23-29 weeks in gestational age. The RPCs were observed in cases after the 27th week of gestation. The capillary-free zone in the macula was observed in cases after the 25th week of gestation. There were two eyes having extremely small and incomplete capillary-free zones: in one eye a vascular network was present in the region corresponding to the center of the macula. It was thought that the vascular network in the temporal horizontal aspect of the macula is formed by anastomosis of the superior and inferior temporal vessels, and that the capillary-free zone in the macula develops secondarily as the result of retraction of the capillaries.

Characterization of human peripheral blood T lymphocytes bearing receptors for autologous erythrocytes and T lymphocytes lacking these receptors

When human T cells were treated with neuraminidase from Vibrio cholerae, the capacity of T cells to form rosettes with autologous erythrocytes was markedly enhanced. The neuraminidase-treated T cells wee separated with autologous erythrocytes into autorosetting and nonrosetting cell populations, and these two populations examined for their reactivity to mitogens and B cells and for their regulatory activities. Autorosetting T cells proliferated poorly in response to mitogens and autologous and allogeneic B cells; these cells were particularly enriched for cells capable of becoming concanavalin A-induced suppressor cells. Nonrosetting T cells capable of most actively proliferating in response to the mitogens and the B cells failed to exhibit such suppressor function after concanavalin A activation. Coculture experiments between autorosetting and nonrosetting cells further demonstrated that the nonrosetting T cells were able to potentiate the proliferation of the autorosetting T cells with concomitant expression of the suppressor properties.

The origin of amyloid in gelatinous drop-like corneal dystrophy

The origin of amyloid in gelatinous drop-like corneal dystrophy, one of the primary corneal amyloidoses, was studied by light and electron microscopy. Milky-white granules over the corneal surface are the first clinical findings. In the initial stage, the amyloid substance exists between the basal cell of the corneal epithelium and the basal lamina of the cell. The basal lamina, Bowman's membrane and the stroma remained intact. Numerous filaments, about 7nm in width, were seen in the normal basal cells. In addition, many fibrils, about 10nm in width, were observed in the damaged basal cells. With progressing of the disease, the amyloid increased in amount and Bowman's membrane disappeared. Our results suggest that the basal cell of the corneal epithelium may produce and secreted the amyloid substance and gelatinous drop-like corneal dystrophy occurred.

Separation of concanavalin A-induced human suppressor and helper T cells by the autologous erythrocyte rosette technique

Very few normal human peripheral blood T cells are capable of binding autologous erythrocytes to form rosettes, whereas in the T cell population activated by concanavalin A (Con A) the autorosette levels are markedly enhanced. Fractionation of the Con A-activated T cells with autologous erythrocytes into autorosetting and nonrosetting cells demonstrates that suppressor, but not helper, activity resides in the autorosetting population, whereas the reverse is true of the nonrosetting population. Both these activities are found to be Con A dependent. The Con A-induced human suppressor cells can be identified and separated from the Con A-induced human helper cells by the autorosette technique. Studies on the surface properties of autorosetting and nonrosetting T cells indicate that there is little correlation between the activated suppressor and helper T cell subsets defined by autorosette technique and either those defined by monoclonal antibodies (which are able to distinguish these subsets in the resting but not activated T cells) or those defined by Fc receptors. Since the autorosetting T cell population (which acts as suppressor cells) bears receptors for peanut agglutinin, the nature of Con A-induced human suppressor cells appears to be analogous to that of Con A-induced murine suppressor cells.

Platelet aggregation and coagulation in the pathogenesis of diabetic retinopathy in rats

Fifty male rats were made diabetic by a single injection of streptozotocin and were killed at periods varying from 1 to 12 mo. Ten saline-injected rats and three rats treated with 3-O-methylglucose and streptozotocin served as controls. Intraluminal changes in retinal vessels were studied by electron microscopy. In diabetic rats maintained for 9-12 mo, microthrombus formation was observed in the various sized retinal vessels at the histologic and ultrastructural level. The microthrombi were mainly composed of aggregated platelets and fibrin strands. However, there was no definite evidence of detachment or loss of the endothelial cells. This microthrombus formation may play an important role in the development of diabetic retinopathy.