Thyroid follicular adenoma with accumulation of collagen type IV in a common marmoset (Callithrix jacchus).

A thyroid tumour was identified in a 10-year-old male common marmoset (Callithrix jacchus). The tumour was encapsulated by fibrous connective tissue and compressed the adjacent normal thyroid. The tumour was composed of variably sized and irregularly shaped thyroid follicles lined by a single layer of columnar epithelial cells. Eosinophilic material at the base of the neoplastic cells stained black with periodic acid-methenamine silver and red with periodic acid-Schiff. Immunohistochemistry confirmed that this eosinophilic material was collagen type IV. Ultrastructurally, highly dense and amorphous material was observed at the base of the neoplastic cells. Small vesicles in the basolateral cytoplasm of the neoplastic cells contained similar material to that at the base of the cells. The tumour was diagnosed as a thyroid follicular adenoma with accumulation of collagen type IV. This is the first description of an endocrine tumour with accumulation of collagen type IV in animals.

Malignant amelanotic melanoma behind the left eye in a female Crj:CD(SD)IGS rat: a case report.

A tumor behind the left eye in a female Crj:CD(SD)IGS rat was investigated histopathologically, immunohistopathologically, and electron microscopically. The tumor invaded and destroyed orbital tissues and bones. It consisted of various tumor cells; namely, spindle-shaped, epithelioid, anaplastic melanoma cells, and had prominent eosinophilic cytoplasm and nuclei with a greater variation in size. Immunohistochemically, almost all of the tumor cells were positive for antimelanoma, PNL2 antibody. Ultrastructurally, the tumor cells were rich in small vesicles containing fine granules and filamentous structures. This is the first report describing an amelanotic melanoma in the head of an albino rat.

A novel immunohistochemical marker of normal and neoplastic melanocytes in formalin-fixed, paraffin-embedded tissues of albino rats.

In albino rats, spontaneous occurrence of melanocytic tumors is rare, with diagnosis difficult. This study evaluated immunoreactivity for PNL2 in normal and neoplastic melanocytes in formalin-fixed and paraffin-embedded tissues of albino rats. The samples consisted of 11 (1.57%) amelanotic melanomas in 700 rats (2 studies), 23 non-melanocytic tumors, and a wide variety of normal tissues. In normal albino rats, PNL2 stained the melanocytes in the iris and choroid of the eyeball and the hair bulb and basal cell layers of the epidermis of the whole body. In amelanotic melanoma, the tumor cells consisted of spindle cells with eosinophilic cytoplasm without melanin granules. PNL2 consistently stained cytoplasm in all amelanotic melanoma cells. In contrast, the nonmelanocytic tumor cells were not labeled. Electron microscopically, neoplastic, and normal melanocytes showed numerous cytoplasmic premelanosomes (stage II melanosome). In conclusion, PNL2 is direct against a fixative- and decalcific-resistant melanocyte-associated antigen, and has high specificity against normal and neoplastic melanocytes of albino rats.

Eosinophilic substance is "not amyloid" in the mouse nasal septum.

An eosinophilic substance (ES) is usually observed in the mouse nasal septum and increases in volume with aging. It has been described as amyloid in textbooks and one report. However, it has been described as "not amyloid" in other reports because there was a negative reaction to Congo red. In this study, the ES was investigated histopathologically and electron microscopically to determine whether it was amyloid or not. The ES was only observed at the interstitium of clear HE-stained nasal glands in the septum, in which 2 kinds of glands were present (dark and clear stained by HE). The volume of the ES was small in young mice and large in older ones. Neither nasal gland degeneration nor inflammation resulted, even if a large amount of the ES was observed. The ES reacted negatively to Congo red but was strongly positive to periodic acid-Schiff reaction with prior diastase treatment. In the electron microscope observation, the ES consisted of amorphous material and collagen, but no nonbranching fibrils. Similar amorphous material was also observed in the nasal gland epithelial cells and was connected to the material in the rough endoplasmic reticulum. The above-mentioned findings indicated that the ES was not amyloid and suggested the ES might consist of not only collagen but also complex carbohydrate, which was produced by the nasal gland epithelial cells.

8-Hydroxydeoxyguanosine levels in white blood cell DNA and ex vivo oxidation resistance of plasma in smokers.

Oxidative DNA damage in peripheral white blood cell of smokers were estimated in accordance with the levels of 8-Hydroxydeoxyguanosine (8-OHdG) in nuclear DNA and the antioxidant status of these smokers' plasma was investigated in terms of the ex vivo oxidation resistance of plasma. In a survey of 12 smokers (4 women) aged 22 to 48, the mean level of 8-OHdG was 3.79+/-0.65 residue/10(6) dG (mean +/- S.D.) with a range from 2.83 to 4.62 residue/10(6) dG. These measurements showed approximately 1.6-fold inter-individual variations of 8-OHdG level in smokers. A higher level of 8-OHdG was found for smokers whose ex vivo plasma oxidation resistance was weak. Significant association is seen between oxidized bases in white blood cells and plasma oxidation resistance, whereas signs of any association with plasma concentration of alpha-tocopherol, ascorbic acid, bilirubin, and uric acid are weak and sporadic. These findings indicate that apparent heterogeneity exists among smokers in some sort of resistance to the oxidative effects of smoking.

Thyroid hyperactivity induced by methimazole, spironolactone and phenobarbital in marmosets (Callithrix jacchus): histopathology, plasma thyroid hormone levels and hepatic T4 metabolism.

To determine drug-induced hyperfunction of marmoset thyroids due to inhibition of synthesis or enhancement of metabolic elimination of thyroid hormones, males were orally administered 10 and 30 mg/kg/day methimazole (MMI), 30 and 100 mg/kg/day spironolactone (SPL), or 50 mg/kg/day phenobarbital (PB) for 4 weeks. MMI caused marked hypertrophy of follicular epithelial cells in accordance with a significant decrease in the plasma thyroxin (T4) level. Hypertrophied epithelial cells were filled with dilated rough endoplasmic reticulum and reabsorbed intracellular colloids, and the luminal surface was covered with abundant microvilli. The colloid included vacuoles positive to anti T4 immuno-staining. SPL and PB also caused similar histomorphological changes, although they were less severe than those due to MMI and were not clearly associated with decrease in the plasma T4 levels. Hepatic T4 UDPGT activities tended to increase due to SPL and PB treatment, however, which were not so significant as increases in microsomal cytochrome P-450 contents. Some animals treated with SPL and PB showed marked increases in thyroid weights due to inactive dilated follicles. In conclusion, hyperactivity of thyroid follicles was induced in marmosets not only due to inhibition of T4 synthesis produced by MMI but also because of enhancement of hepatic T4 elimination produced by SPL and PB. However, hypertrophic effects of SPL and PB were less severe than MMI, because plasma T4 levels were maintained at almost pretreatment or control levels after SPL or PB treatment.

Lysyl oxidase coupled with catalase in egg shell membrane.

The activity of lysyl oxidase was found in egg shell membrane (ESM) of hens. The activity was determined by measuring the enzymatic conversion of n-butylamine and Nalpha-acetyl-L-lysine to n-butyraldehyde and Nalpha-acetyl-L-allysine, respectively. ESM lysyl oxidase was significantly inhibited by beta-aminopropionitrile, chelating agents, and deoxygenation, consistent with the known properties of lysyl oxidase. Nevertheless, ESM lysyl oxidase was insoluble in urea solution, suggesting that it complexes with ESM. These findings support previous reports indicating the presence of lysine-derived cross-links in ESM and the necessity of lysyl oxidase located in the isthmus of the hen oviduct for the biosynthesis of ESM. Lysyl oxidase secreted around the egg white from the isthmus may initiate the cross-linking reaction of ESM protein, and remain as the constituent of ESM. Moreover, the H(2)O(2) released by lysyl oxidase in ESM was completely decomposed by coexisting catalase activity. ESM lysyl oxidase activity was greatly elevated in the presence of H(2)O(2), probably due to the O(2) produced by catalase. These findings indicate that lysyl oxidase is coupled with catalase in ESM. This coupling enzyme system was considered to be involved in the biosynthesis of ESM and to protect the embryo against H(2)O(2).

Case report: spontaneous hemangiosarcoma in the pancreas of a Fischer rat.

Spontaneous hemangioma or hemangiosarcoma is sometimes found in the viscera and soft tissue of rats and mice. However, there is no report of the tumor occurring in the pancreas of rats. We report a pancreatic hemangiosarcoma in a 109-wk-old, male Fischer 344 rat, which was used in the control group of a carcinogenicity study. The tumor destroyed and compressed the normal pancreatic tissue and displayed a high density in terms of the numerous capillaries and strands of endothelial tumor cells. A reticulin stain revealed a dense network formation. The frequency of proliferating cell nuclear antigen-positive staining showed active proliferation of the tumor cells. Immunohistochemically, some of the tumor cells stained positive with factor VIII-related antigen, and ultrastructurally, Weibel-Palade bodies were rarely observed in the cytoplasm of the tumor cell. From these findings, the tumor was diagnosed as a hemangiosarcoma that occurred naturally in the pancreas.

Gangliocytoma with immature neuronal cell elements in the pituitary of a rat.

A spontaneous pituitary gangliocytoma with abundant, immature neuronal cell elements was found incidentally in a 109-week-old female Fischer 344 rat. The pituitary parenchyma was largely occupied by a tumor nodule with necrotic and hemorrhagic foci and cyst. The tumor was composed of mature ganglion-like (M) cells, small immature ganglion (I) cells and transitional (T) cells, with a fibrillar matrix. The I and T cells were intermingled with the M cells or were arranged in compact clusters, in which the I cells formed perivascular rosette-like structures, sometimes with mitotic figures. Immunohistochemically, all types of tumor cells were positive for neuron-specific enolase, and only the M cells was positive for chromogranin A. This result may be correlated with the degree of cytodifferentiation.

Angiotensin I-converting enzyme inhibitors in autolysates of squid liver and mantle muscle.

Autolysis of squid liver and mantle muscle homogenates, and blends of both, each yielded inhibitory activity toward the angiotensin I-converting enzyme. The inhibitory activity and the amount of solubilized protein in each of these autolysates were examined over a period of 24 h. Inhibitory peptides were isolated from the mixed autolysate, their structures (IC50) being Tyr-Ala-Leu-Pro-His-Ala (9.8 microM) and Gly-Tyr-Ala-Leu-Pro-His-Ala (27.3 microM).

Spontaneous lesions detected in the common cotton-eared marmosets (Callithrix jacchus).

Spontaneous lesions in the common cotton-eared marmosets (Callithrix jacchus), which were maintained in our laboratory or were purchased from a commercial breeder, were examined histopathologically. There were 39 males and 22 females, between the ages of 7 and 100 months. The most interesting finding noted was extramedullary hematopoiesis, which was observed in the mesenteric lymph nodes, spleen, liver, kidney, adrenal gland, and cerebral choroid plexus. Megakaryocytes were frequently observed in the blood vessels of the alveolar wall of the lung. It is important to distinguish extramedullary hematopoiesis which occurs accidentally from that induced by repeated blood sampling or that resulting from administration of chemicals. Extramedullary hematopoiesis was easily distinguishable from inflammation or hematopoietic neoplasms, because of the various cellular elements present, including megakaryocytes. In the weak and dead animals, enterocolitis was found at a high frequency. Other common findings included thymic involution, prominent vacuolation of liver sinusoidal cells, which were probably Ito-cells, and basophilic changes in the renal tubular epithelium. The liver and the kidney are frequently affected by toxic effects of chemicals. Therefore, it is important to distinguish the toxic changes from the spontaneous ones. Proliferation of apocrine glands in the cervical skin was an interesting finding; however, neither inflammatory change nor cellular atypia was noted in this structure. Although its function is unclear, this structure may be a marmoset-specific tissue.

Changes in biliary excretory mechanisms in bile duct-ligated rat.

The effects of bile duct ligation on biliary excretion of bile acids, glutathione, and lipids were studied in the rat. The bile duct of the rat was ligated for three days. The biliary bile acid excretion after bile duct cannulation was higher at first, but after 90 min became lower than that in the control rat. The bile flow in the bile duct-ligated rat was higher after bile duct cannulation and gradually decreased to the same level as in the control rat. Biliary glutathione excretion, which has been suggested to be a driving force for the bile acid-independent canalicular bile flow, was markedly decreased in the bile duct-ligated rat. The mannitol clearance was increased and the bile ductules showed proliferation in the bile duct-ligated rat, suggesting an increase in the ductular bile flow. Biliary excretion of lithocholate glucuronide was more markedly impaired than that of taurocholate. When taurocholate was infused at higher rates, which increases bile flow and biliary excretion of bile acid and lipids in the control rat, biliary bile acid and lipid excretion remained constant in the bile duct-ligated rat. These findings indicate that, in the bile duct-ligated rat, the ductular bile flow was increased and bile acid-independent canalicular bile flow was decreased and that, although the biliary excretion of bile acids was not as impaired as that of organic anions, the capacity of bile acid and lipid excretion was markedly decreased.

Effects of organic anions and bile acids on biliary lipid excretion in hyperbilirubinemic mutant Sprague-Dawley rats.

The effects of organic anions and bile acids on biliary lipid excretion were studied in EHBR, a hyperbilirubinemic mutant Sprague-Dawley rat. A marked delay in the biliary excretion of BSP, cefpiramide, rose bengal and ursodeoxycholate-disulfate was observed in these animals. The marked decrease in the biliary excretion of phospholipids and cholesterol and the uncoupling of biliary bile acids and lipids that occurred after the administration of BSP, cefpiramide and ursodeoxycholate-disulfate in control Sprague-Dawley rats was absent in EHBR. Rose bengal did not change biliary lipid excretion in either the control Sprague-Dawley rats or the EHBR. Although taurocholate markedly increased bile flow and biliary bile acid excretion in both types of rats, the increase in biliary lipid excretion observed in the control Sprague-Dawley rats was absent in EHBR. These findings indicate that EHBR have an impairment of hepatic lipid transfer that is enhanced by bile acids, possibly at the level of intracellular vesicular lipid transport.

Endocrine cell populations in the pancreas of diabetic WBN/Kob rats.

Numerical changes of insulin-, glucagon- and somatostatin-positive cells in the pancreas of WBN/Kob male rats with spontaneously occurring diabetes were examined. The rats examined were divided into three different age groups: Groups I (12 weeks old) and II (33 weeks old) were clinically prediabetic and group III (60-90 weeks old) was diabetic. Serum glucose value was in the normal range in groups I and II, while it was much higher in group III. B and A cells were markedly decreased in number in groups II and III. In group II, the ratio of B to A cells was normally preserved, though the total endocrine cell number was markedly decreased as compared with that in group I. In group III, the percentage of B cells was decreased significantly. The normal ratio in group II seemed to keep serum glucose within the normal level. In addition to the total endocrine cell reduction, an altered ratio of B and A cells was considered to cause the diabetic condition.

[A case of flomoxef-induced pneumonitis].

We report a case of flomoxef-induced pneumonitis. A 22-year-old man was treated with flomoxef following liver biopsy. A few days later he developed a high fever and severe dyspnea, and his chest X-ray film revealed diffuse reticulo-nodular shadows in both lung fields. We suspected interstitial pneumonitis due to flomoxef, and pulse therapy with methylprednisolone was started. He showed rapid recovery of symptoms and marked regression of pulmonary infiltration in his chest X-ray. Lymphocyte stimulation test was positive to flomoxef, which was compatible with the diagnosis of drug-induced pneumonitis. To our knowledge, there has been no previous case of pulmonary hypersensitivity to flomoxef reported in Japan.

Increased hexokinase activity in fetuses of rats developed under maternal hyperglycemia.

Hepatic and diaphragmatic hexokinase (HK) activities increased in fetuses of rats developed under maternal hyperglycemic conditions, compared to those in normal controls. In those organs, Type I and Type II hexokinase isozymes were detected by electrophoresis and densitometry with a chromatoscanner. Densitometric peak that corresponded to hepatic and diaphragmatic Type II hexokinase was also increased in the fetuses developed under hyperglycemia, compared to that of normal fetuses. These findings suggest that in the fetal liver, where significant activity of Type IV was absent, activity of Type II hexokinase varied depending on physiological state such as maternal hyperglycemia.

Purification of rat retinol-binding protein using Blue Sepharose CL-6B.

Studies were conducted to isolate rat plasma retinol-binding protein, the specific transport protein for vitamin A in the rat. Retinol-binding protein was isolated from rat plasma by a new simple procedure using Blue Sepharose CL-6B, and highly purified retinol-binding protein was obtained. This procedure included DEAE-cellulose chromatography at pH 6.0, Sephadex G-75 gel filtration in the presence of 3.0 M urea, Blue Sepharose CL-6B affinity chromatography at pH 7.0 and finally Sephadex G-100 gel filtration at pH 7.4. The third step completely accomplished the dissociation and separation of retinol-binding protein from its complex with prealbumin and plasma albumin. This procedure is a significant improvement over previously published procedures, in which sample recycling and preparative polyacrylamide gel electrophoresis are necessary. The molecular weight, electrophoretic behaviour, ultraviolet and fluorescence spectra of the retinol-binding protein were similar to those appearing in other reports.