Production of thymocyte-stimulating activity by cultured human thyroid epithelial cells.

Since thyroid follicular epithelial cells (thyrocytes) have been shown to express a number of functions similar to monocytes, they were further examined for their potency in secreting thymocyte-stimulating activity (TSA). Although spontaneous production of TSA could not be detected when thyrocytes were cultured in the culture medium, TSA was demonstrated in the culture supernatants after stimulation with the immune adjuvant lentinan. The release of TSA was found in the culture supernatants collected 24 h after stimulation and was maintained for the 4 days of culture. Maximum levels of TSA release were achieved by 2 days. In addition, when culture supernatants of thyrocytes stimulated with lentinan or monocyte-derived interleukin 1 (IL-1) were incubated with a rabbit antibody to human IL-1, a parallel reduction in TSA was observed, suggesting that the active product in the thyrocyte culture supernatant shared a common antigenic site with IL-1. The demonstration of the production of IL-1 like activity by thyrocytes provides additional evidence that these cells, in addition to their functions as endocrine cells, may also participate in the local immune responses under appropriate conditions.     

Isolation of amantadine-resistant influenza a viruses (H3N2) from patients following administration of amantadine in Japan

In Japan, the use of amantadine for treatment of influenza A virus infection was not accepted until November 1998, although it was widely used for treatment of Parkinsonism. Since then, we have monitored the emergence of amantadine-resistant viruses and isolated two viruses from patients on long-term treatment with amantadine.     

The PTEN/PI3K pathway governs normal vascular development and tumor angiogenesis

PTEN is an important tumor suppressor gene. Hereditary mutation of PTEN causes tumor-susceptibility diseases such as Cowden disease. We used the Cre-loxP system to generate an endothelial cell-specific mutation of Pten (Tie2CrePten) in mice. Tie2CrePten(flox/+) mice displayed enhanced tumorigenesis due to an increase in angiogenesis driven by vascular growth factors. This effect was partially dependent on the PI3K subunits p85alpha and p110gamma. In vitro, Tie2CrePten(flox/+) endothelial cells showed enhanced proliferation/migration. Tie2CrePten(flox/flox) mice died before embryonic day 11.5 (E11.5) due to bleeding and cardiac failure caused by impaired recruitment of pericytes and vascular smooth muscle cells to blood vessels, and of cardiomyocytes to the endocardium. These phenotypes depend strongly on p110gamma rather than on p85alpha and were associated with decreased expression of Ang-1, VCAM-1, connexin 40, and ephrinB2 but increased expression of Ang-2, VEGF-A, VEGFR1, and VEGFR2. Pten is thus indispensable for normal cardiovascular morphogenesis and post-natal angiogenesis, including tumor angiogenesis.     

Defects in regulation of apoptosis in caspase-2-deficient mice

During embryonic development, a large number of cells die naturally to shape the new organism. Members of the caspase family of proteases are essential intracellular death effectors. Herein, we generated caspase-2-deficient mice to evaluate the requirement for this enzyme in various paradigms of apoptosis. Excess numbers of germ cells were endowed in ovaries of mutant mice and the oocytes were found to be resistant to cell death following exposure to chemotherapeutic drugs. Apoptosis mediated by granzyme B and perforin was defective in caspase-2-deficient B lymphoblasts. In contrast, cell death of motor neurons during development was accelerated in caspase-2-deficient mice. In addition, caspase-2-deficient sympathetic neurons underwent apoptosis more effectively than wild-type neurons when deprived of NGF. Thus, caspase-2 acts both as a positive and negative cell death effector, depending upon cell lineage and stage of development.     

Evaluation of time-resolved fluorometric immunoassay of CA 50

Serum CA 50 was determined by a time resolved fluorometric immunoassay (TR-FIA) with CANAG CA-50 DELFIA kit. Evaluation of the assay system gave satisfactory results in its sensitivity, accuracy, reproducibility, dynamic range and easy handling. No prozone phenomenon was observed up to 347,000 U/ml. From a histogram of 134 normal sera, the cut off point was determined at 34 U/ml. CA 50 in 202 patients' sera was determined with this assay. Nineteen of 20 patients pancreatic cancer, 6 of 21 gastric cancer, 14 of 25 hepatoma gave positive values. In comparison with CA 19-9, higher values and higher rates of positive CA 50 were observed in benign and malignant liver diseases, suggesting its non-cancerous origin in the liver. A high correlation was observed between the level of CA 50 and CA 19-9 of 157 patients' sera. Serum CA 50 was completely correlated with CA 19-9 in the clinical course of patients with pancreatic cancer, but not in patients with hepatoma. Thus we conclude that the CANAG CA-50 DELFIA System is useful for the diagnosis and monitoring cancer patients but must be used with care because of its elevation in benign liver diseases.     

FLUORESCENCE AND ELECTRON MICROSCOPIC STUDIES ON THE PERIVASCULAR MESENCHYMAL CELLS AND FIBROBLASTS AFTER VITAMIN A ADMINISTRATION

Findings of perivascular mesenchymal cells and fibroblasts in mice receiving large doses of vitamin A were described. Liver, lung, intestine and skin were investigated by fluorescence and electron microscopy. Marked increase of fluorescence of vitamin A was observed in the sinusoidal wall of the liver, in the alveolar septa of the lungs, in the propria mucosa, submucosa and muscular layer of the intestine and in the dermis of the abdominal skin. Increased fluorescence of these organs corresponded, ultrastructually, to the appearance of numerous fat droplets in Ito cells of the liver, septal cells of the lung and fibroblasts of the intestine and of the skin. All of these cells showed the same morphological features and the same distribution in the tissue, namely in the interstitial connective tissue space. These findings indicate that vitamin A storing cells are distributed widely in the connective tissue of various organs and that perivascular vitamin A storing mesenchymal cells and interstitial fibroblasts are probably of common fibroblastic cell line.     

Dedifferentiated adenoid cystic carcinoma: a clinicopathologic study of 6 cases.

Dedifferentiated adenoid cystic carcinomas are a recently defined, rare variant of adenoid cystic carcinomas characterized histologically by two components: conventional low-grade adenoid cystic carcinoma and high-grade "dedifferentiated" carcinoma. We examined six cases and analyzed their clinicopathologic profiles, including immunohistochemical features and p53 gene alterations. The 6 patients (3 men and 3 women) had a mean age of 46.8 years (range, 34-70 y). The mean size of the tumors was 3.5 cm (range, 1.7-6 cm). The submandibular gland, maxillary sinus, and nasal cavity were involved in 2 cases each. Postoperatively, 5 patients had local recurrence and 5 developed metastatic disease. Five patients died of disease at a mean of 33.7 months after diagnosis (range, 6-69 mo), and one other was alive with disease at 60 months. Histologically, the conventional low-grade adenoid cystic carcinoma component of the tumors consisted of a mixture of cribriform and tubular patterns with scant solid areas. The high-grade dedifferentiated carcinoma component was either a poorly differentiated adenocarcinoma (4 cases) or undifferentiated carcinoma (2 cases). Three tumors were studied immunohistochemically. Myoepithelial markers were expressed in low-grade adenoid cystic carcinoma but not in the dedifferentiated component. In 2 cases, diffusely positive p53 immunoreactivity together with HER-2/neu overexpression was restricted to the dedifferentiated component. Loss of pRb expression was demonstrated only in the dedifferentiated component of the 1 other case. The Ki-67-labeling index was higher in the dedifferentiated component than in the low-grade adenoid cystic carcinoma component. Furthermore, molecular analysis of 2 cases demonstrated the loss of heterozygosity at p53 microsatellite loci, accompanied by p53 gene point mutation, only in the dedifferentiated carcinoma component of 1 case, which was positive for p53 immunostaining. These results indicate that dedifferentiated adenoid cystic carcinoma is a highly aggressive tumor. Because of frequent recurrence and metastasis, the clinical course is short, similar to that of adenoid cystic carcinomas with a predominant solid growth pattern. Limited evidence suggests that p53 abnormalities in combination with HER-2/neu overexpression or loss of pRb expression may have a role in dedifferentiation of adenoid cystic carcinoma.     

TWO CASES OF ACQUIRED TOXOPLASMIC LYMPHADENITIS. Light and Electron Microscopic and Immunohistochemical Studies

We report two cases of acquired toxoplasmic lymphadenitis, one with toxoplasmic cysts and the organisms of Toxoplasma gondii and the other with the organisms only. These cysts and organisms were observed in paraffin-embedded sections, touch smears and ultrathin sections for electron microscopy. Touch smears were especially valuable for the quick and accurate diagnosis of toxoplasmic lymphadenitis. We also studied immature sinus histiocytosis (ISH) in these cases. The predominant cells of ISH were confirmed to be B lymphocytes immunohistochemically, the majority being positive for polyclonal surface IgM. ISH was observed in the perifollicular and paracortical areas surrounding post-capillary venules (PCV), whereas the sinuses were only partially involved.     

Synthesis and characterization of poly(1-benzoylthiosemicarbazide) and poly(1,3,4-thiadiazole amine) from 2-(p-aminophenyl)-1,3,4-oxadiazoline-5-thione via ring-opening process

A novel thermally stable and semiconducting polyheterocycle, poly(1,3,4-thiadiazole amine), was synthesized from 2-(p-aminophenyl)-1,3,4-oxadiazoline-5-thione via ring-opening. The polymer is a new class of ordered alternating copoly(aniline) containing 1,3,4-thiadiazole heterocyclic units. An investigation of the reaction of 2-phenyl-1,3,4-oxadiazoline-5-thione with aniline was conducted as a model reaction for the polymerization, and poly(phosphoric acid) (PPA) and phosphorus pentoxide/methanesulfonic acid (PPMA) were found to be favorable both as condensing agent and solvent for the formation of 2-anilino-5-phenyl-1,3,4-thiadiazole as a model compound. The polymerization was carried out both by two-step procedure that included ring-opening self-polyaddition giving poly(1-benzoylthiosemicarbazide), followed by cyclodehydration to poly(1,3,4-thiadiazole amine), and by a one-step procedure including cyclodehydration in situ. The poly(1-benzoylthiosemicarbazide) which was formed in the first step in m-cresol had reduced viscosities up to 0,42 dL·g^?1, and it was converted to poly(1,3,4-thiadiazole amine) by treating in PPA or PPMA. Poly(1,3,4-thiadiazole amine) having reduced viscosities up to 0,25 dL·g^?1 was also synthesized by the direct one-step polymerization in PPA or PPMA. The polymer is highly thermally stable and exhibited no weight loss up to 350°C under nitrogen. Its electric conductivity was less than 10^?10 S·cm^?1 at ambient temperature, but markedly increased to 2,9·10^?7 S·cm^?1 upon doping with iodine.     

Bovine serum albumin (BSA) nephritis in rats II. Histological findings and complement activation by immune complex in SHR rats.

We introduced a mesangiopathic form of glomerulonephritis in spontaneously hypertensive (SHR) rats. Bovine serum albumin (BSA) was given i.v. to primed rats for 3 weeks and they were unilaterally nephrectomized (Nx). Then, they received rabbit anti-BSA- (Group A) or normal serum (Group B) for seven days, and half the rats were killed to obtain another kidney (Ex-1). The remainder were killed two weeks later and their kidneys were examined (Ex-2). In Nx kidneys, the glomerular lesions were characterized by leucocyte accumulation in the capillary lumina and by deposition of rat IgG, rat C3 and BSA both in the mesangial area and along the capillary walls. Glomeruli of Ex-1 kidneys manifested varying degrees of hypercellularity in the mesangium; a few leucocyte accumulations in the capillary lumina were noted and the immune deposits had decreased in the mesangium but not on the capillary walls. In Ex-2 kidneys, mesangial hypercellularity was conspicuous. There were no remarkable histological differences between Group A and B rats; in Ex-1 and Ex-2 kidneys of Group A, rabbit IgG was closely associated with rat IgG or C3. Serological evaluation revealed that the amount of circulating rat anti-BSA antibody was relatively small and that C3 was consumed by newly formed circulating immune complexes during BSA administration. Polymorphonuclear leucocyte (PMN) binding assay revealed that complement fixation to the immune deposits occurred in vitro and that this activity was highest in tissue from Nx kidneys.