Histologic and electron microscopy observations on diethylnitrosamine-induced hepatomas in small aquarium fish (Oryzias latipes).

Liver neoplasms were induced in medakas (Oryzias latipes) by the addition of diethylnitrosamine (DENA) to their aquarium water at levels of 15-135 ppm for 8 weeks. After 13 weeks, 21 to 32 fish had developed hepatomas. Medakas are useful for further studies because they are highly susceptible to the carcinogenic effect of DENA, and the time for tumor induction is relatively short. Histologic type differed in the lesions of different fish and also within individual tumors. Some were typical trabecular hepatomas, others were anaplastic hepatomas or cholangiomas, or mixtures of these. Electron microscopy revealed an extensive rough-surfaced endoplasmic reticulum in a lamellar pattern, many mitochondria, and several round lysosomes in tumor cells. A few fat droplets with occasional crystalline ghosts were sometimes in the cytoplasm. The Golgi apparatus was not conspicuous. Some cells had highly developed microvilli that showed differentiation toward structures resembling bile capillaries.

Reactive lymphoid hyperplasia of the stomach. An immunohistochemical study.

The surgically excised stomachs were re-examined histopathologically, and eighteen cases were placed in the category of reactive lymphoid hyperplasia (RLH). The distribution and the classes of infiltrating immunoglobulin (Ig) bearing cells were examined on lesions of RLH cases together with ten histopathologically determined malignant lymphomas (ML) of the stomach and the control stomachs. It was found that in eleven cases of RLH and one case of ML, many lymphoid cells bearing different classes of Ig were present in those lesions in an intermingled way (polyspecific group). Meanwhile, lymphoid cells in three RLH cases and two ML cases bore only a single monospecific Ig (monospecific group). In other cases, the number of Ig bearing cells were not sufficient to reach any clear conclusions (undetermined group). It was speculated that regardless of the histopathological diagnosis, the monospecific group might belong to the category of neoplasm of B cell type and the polyspecific group in the category of true reactive process. The possible histopathological criteria for differentiation of the reactive process and lymphoid neoplasm of the stomach were re-checked, and the importance of immunohistochemical study on these cases were stressed.

Generalized aspergillosis showing a granulomatous pattern.

An autopsy case of a very rare form of generalized aspergillosis with a prominent granulomatous pattern simulating sarcoidosis was presented. The patient was a forty-year-old Japanese female with a four years' clinical course. Kveim's test was positive. Multiple epithelioid cell granulomata as well as necrotizing and suppurative lesions were recognized in generalized lymph nodes, liver, epicardium, gall bladder, adrenals, kidneys and duodenal mucosa. Fungal elements in the epithelioid cell granulomata and necrotizing lesions were identified as Aspergillus by fluorescent antibody technique (indirect method). Predisposing factors for the generalized fungal infection could not be clarified in this case. There was neither underlying disease nor evident immunodeficiency state, so far as examined.

A seventy-year history of the Japanese pathological society.

This paper provides the chronological outline of the Society's activities during the past seventy years. Membership, which started from a mere 204, has now reached a total of nearly 3,000. This seventy-year history shows that the Society has repeatedly adapted itself to the progress of science and to the trends of the time.

An autopsy study of lung cancer in University of Tokyo for the last 27 years, from 1958 to 1984, with special reference to the characteristics of lung cancer in Japan.

Four hundred and sixty-five male and 159 female consecutive autopsy cases of lung cancer, autopsied over the 27 years from 1958 to 1984, were analysed and were compared with other materials and mortality statistics, including statistics from other countries. Malignant tumor autopsy cases are gradually increasing and now comprise more than 60% of total autopsy cases. The percentage of lung cancer cases among all autopsy cases was 7% in males and 4% in females. The percentage of lung cancer in autopsies of patients with malignancies was about 13% for males and 9% for females. The most frequent fatal malignant tumors were gastric cancer, lung cancer, and leukemia. The relative incidence of gastric cancer was decreasing, while that of lung cancer was increasing. In the distribution of the histological types of lung cancer, adenocarcinomas were the most frequent types in both sexes. As has been noted in mortality statistics, we noticed a gradual shift in the peak age of lung cancer autopsy cases towards older patients. During the period under study, the peak shifted from patients in their sixties to patient in their seventies; this was true for most of the major histological types in both sexes. The male/female ratio of all lung cancer cases was 2.9, which was much lower than the ratio found in the United States and Europe, and very similar to the ratio of the mortality rates in Japan and other Asian countries. It was pointed out that the male/female ratios by age-group in each country is a very good reflection of the histological distribution.

The distribution of cells expressing a natural killer cell marker (HNK-1) in normal human lymphoid organs and malignant lymphomas.

A murine monoclonal antibody, HNK-1, is known to react with some human leukocytes including all natural killer (NK) cells in peripheral blood. The distribution of cells reacting with this antibody (HNK-1+ cell) was studied in human peripheral lymphoid organs, consisting of five lymph nodes, two specimens of gastric mucosa with lymphoid tissue, two tonsils, one appendix, and two thymuses. Fourteen cases of malignant lymphoma (ML) were also examined. For the demonstration of HNK-1+ cells, the peroxidase-antiperoxidase (PAP) bridge method was applied to cryostat sections of these specimens. It was found that in normal lymphoid organs most HNK-1+ cells were located in lymph follicles, especially in germinal centers, and some were found in 'mixed' regions which indicate outsides of both the follicles and T-zones. Amongst the ML, large clusters of HNK-1+ cells were observed only in two cases of follicular lymphoma, although a few scattered HNK-1+ cells were noted in other ML, including five diffuse B-cell lymphomas, six T-cell lymphomas and one null cell lymphoma. The possible significance of these findings is discussed.

Familial amyloid polyneuropathy with marked hypertrophy of the peripheral nerves.

Autopsy findings in a 40-year-old male with heredofamilial amyloidosis and polyneuropathy are reported. He had been suffering from progressive autonomic as well as sensorimotor dysfunctions. Prominent amyloid deposit was found in the kidney, heart, thyroid, and testis, and less in the interstitium and small vessels of almost all organs. The peripheral nerves, some showing prominent hypertrophy, were most severely involved by amyloid deposit in a form of stellate mass, which ultrastructurally consisted of radially arranged amyloid filaments. In the hypertrophied nerves and ganglia, in addition to amyloid, massive accumulation of acid mucopolysaccharide (AMPS) was seen filling up the interstitial space, which was the cause of hypertrophy. Ultrastructurally, AMPS was seen as finely granular substance. An extracted amyloid from the kidney showed 8 nm filament on negative staining and was estimated of having a molecular weight of 14,000.