Thymic sarcomatoid carcinoma with skeletal muscle differentiation: report of two cases, one with cytogenetic analysis.

AIMS: Malignant thymic tumour histologically resembling a soft tissue sarcoma is extremely rare and defined as sarcomatoid carcinoma in the recent World Health Organization (WHO) classification. We report two such cases in which the tumour cells showed a prominent rhabdomyoblastic differentiation and analyse whether these tumours retain an epithelial nature at least in part. METHODS AND RESULTS: One tumour occurred in a 51-year-old man (Case 1) and the other in a 40-year-old woman (Case 2). Microscopically, both tumours consisted essentially of two types of tumour cells: spindle and large round cells, with no apparent epithelial components. Osteosarcomatous small foci were also found in Case 2. Immunohistochemically, desmin and muscle-specific actin were positive in the majority of both types of tumour cells, whereas myogenin was predominant in the spindle cells and myoglobin in the large round cells. Some of both types of cells expressed cytokeratin with co-expression of myoglobin in the large round cells, but with no myogenin in the spindle cells. Some cytokeratin-positive spindle cells were also negative for desmin. Ultrastructural examination of a recurrent tumour in Case 2 revealed some epithelial features among the spindle cells. Cytogenetic study of the same tumour showed a complex abnormality including der(16)t(1;16)(q12;q12.1), an identical pattern previously reported in a case of thymic squamous cell carcinoma. CONCLUSIONS: The findings support the definition in the WHO classification of sarcomatoid carcinoma that includes purely sarcomatous tumour as in the present cases. Occurrence of this type of tumour may indicate a relationship between thymic epithelial cells and myoid cells and/or a potential for divergent differentiation in thymic epithelial tumours.

Effects of hydrocortisone on the formation of gap junctions and the abnormal growth of cilia within the rat anterior pituitary gland: possible role of gap junctions on the regulation of cell development.

We investigated the effects of hydrocortisone on the formation of gap junctions in and the growth of cilia on folliculo-stellate cells. The male rats of experimental groups were given daily intraperitoneal injections of 5 mg/kg of hydrocortisone from Day 20 to 60. Five rats were killed at ages 10, 20, 30 and 40 days after initiation of injections, and the pituitary gland was removed from each rat. Then, the specimens were prepared for observation by transmission electron microscopy. A delay in the formation of gap junctions between folliculo-stellate cells was observed in hydrocortisone treated rats compared with control rats on Day 30, 40 and 50. Another finding in the present study was the increase of ciliated follicles on Day 40 and 50 in the hydrocortisone treated groups, simultaneous with the delay in gap junction formation. The results suggest that hydrocortisone has a suppressive effect on the gap junction formation between folliculo-stellate cells, and loss of intercellular communication by way of gap junctions may lead to alteration of morphological development of the cell.

Anti-rheumatic compound aurothioglucose inhibits tumor necrosis factor-alpha-induced HIV-1 replication in latently infected OM10.1 and Ach2 cells.

NF-kappaB is a potent cellular activator of HIV-1 gene expression. Down-regulation of NF-kappaB activation is known to inhibit HIV replication from the latently infected cells. Gold compounds have been effectively used for many decades in the treatment of rheumatoid arthritis. We previously reported that gold compounds, especially aurothioglucose (AuTG) containing monovalent gold ion, inhibited the DNA-binding of NF-kappaB in vitro. In this report we have examined the efficacy of the gold compound AuTG as an inhibitor of HIV replication in latently infected OM10.1 and Ach2 cells. Tumor necrosis factor (TNF)-alpha-induced HIV-1 replication in OM10.1 or Ach2 cells was significantly inhibited by non-cytotoxic doses of AuTG (>10 microM in OM10.1 cells and >25 F.M in Ach2 cells), while 25 microM of the counter-anion thioglucose (TG) or gold compound containing divalent gold ion, HAuCl3, had no effect. The effect of AuTG on NF-kappaB-dependent gene expression was confirmed by a transient CAT assay. Specific staining as well as electron microscopic examinations revealed the accumulation of metal gold in the cells, supporting our previous hypothesis that gold ions could block NF-kappaB-DNA binding by a redox mechanism. These observations indicate that the monovalent gold compound AuTG is a potentially useful drug for the treatment of patients infected with HIV.

Inhibition of IL-6 and IL-8 induction from cultured rheumatoid synovial fibroblasts by treatment with aurothioglucose.

Gold compounds have long been used in the treatment of rheumatoid arthritis (RA). However, their actions in RA have not been clarified. In this study, we examined the effect of one of the monovalent gold compounds, aurothioglucose (AuTG), on the IL-1-induced production of IL-6, IL-8 and granulocyte macrophage colony stimulating factor (GM-CSF) from rheumatoid synovial fibroblasts (RSF) isolated from three RA patients. IL-6 and IL-8 induction but not GM-CSF induction was inhibited in most of the RSF after pretreatment with AuTG. Since gene expression of these cytokines is known to be under the control of a common transcription factor, NF-kappaB, the effect of AuTG on the cellular localization of NF-kappaB (p65 subunit) and on NF-kappaB-DNA binding was examined. Although AuTG treatment did not prevent NF-kappaB nuclear translocation, AuTG blocked the DNA-binding activity of NF-kappaB when examined in vitro. Morphologically, both metal-specific cell staining using p-dimethylaminobenzylidene rhodamine and transmission electron microscopic examinations demonstrated the accumulation of metal gold in the cytoplama and some organella (mitochondria and lysosomes) of the AuTG-treated RSF. These results indicate that one of the anti-rheumatic actions of AuTG might be through its inhibitory action on NF-kappaB.

Folliculo-stellate cells and intercellular communication within the rat anterior pituitary gland.

Folliculo-stellate (FS) cell are agranular and arranged around a follicle. They contain the S-100 protein and beta-adrenergic receptors. It has been suggested that they can act as stem cells, since they show mitotic figures, and could transform into granular or chromophilic cells according to the concept of a "cell renewal system." Cell-to-cell interactions among pituitary cells have been described, and recent progress with freeze-fracture electron microscopy has provided novel observations of the cell surface and gap junctions within the rat or teleost fish pituitary gland, or in cultured rat pituitary cells. In adult rats, the anterior pituitary was composed of lobules incompletely separated by a basement membrane. Follicles consisted exclusively of FS cells. Gap junctions were observed only between adjacent FS cells, in rare cases on the tips of their cytoplasmic processes. Thus, the FS cells, connected by gap junctions, made up a dense cellular network throughout the pituitary. Gap and tight junctions were absent on granular cells. Elongated follicles with columnar FS cells were observed in 10-day-old rats and were separated into smaller units. The number of gap junctions rapidly increased with age until 40-45 days of age. Few S-100 protein positive cells were observed on day 10, along the marginal cell layer and near the so-called postero-lateral wing. The frequency of positive cells increased with age and by day 40; numerous cells were observed throughout the anterior lobe. Gap junction number also varied with the stage of the estrous cycle, and frequency; during diestrus, they were half of that during proestrus or estrus. The number of gap junctions increased in late pregnancy and in lactating rats, probably due to changes in estrogen and progesterone. Hormone (LH-RH and testosterone) treated groups of rats showed accelerated development by almost 10 days, compared with controls. In castrated male rats, the ultrastructure of the pituitary remained immature even at 40 days of age, when the number of gap junctions was a quarter or less than the number in intact rats. Testosterone treatment restored the frequency of gap junctions to a normal level. We conclude that the appearance of gap junctions in the pituitary cells and maturation of the gland are dependent to a large degree upon gonadal steroids.

Endotoxin-induced upregulation of type I interleukin-1 receptor mRNA expression in hepatocytes of mice: role of cytokines.

Interleukin-1 (IL-1) signal is transduced through the type I IL-1 receptor (IL-1RI). Although regulation of IL-1R expression has been extensively studied in vitro, little is known about it in vivo. By using RT-PCR analysis, we investigated the regulation of the IL-1RI mRNA expression level in various organs of mice at 2, 6, and 24 h following lipopolysaccharide (LPS) administration. IL-1RI mRNA expression in response to LPS appeared to be different in various organs. As a marked and sustained increase of IL-1RI mRNA expression in the liver was observed, we investigated the mechanism of the upregulation. IL-1, IL-6, and tumor necrosis factor (TNF) all increased the mRNA expression in the liver when administrated in vivo. In situ hybridization revealed that upregulation of IL-1R mRNA was observed in parenchymal liver cells (hepatocytes) in response to LPS administration. When primary cultured hepatocytes were treated in vitro, IL-1, IL-6, conditioned medium from LPS-treated mouse macrophages, and serum from LPS-treated mouse upregulated IL-1RI mRNA expression, but LPS, TNF, and prostaglandin E2 failed to do so. Therefore, these results suggest that the upregulation of IL-1RI mRNA in the hepatocytes by LPS administration is mediated by cytokines, especially by IL-1 and IL-6. The results also indicate that the regulation is different in different organs, and microenvironmental factors may be important.

Participation of endodermal epithelial cells on the synthesis of plasma LDL and HDL in the chick yolk sac.

We ultrastructually examined the chick yolk sac endodermal epithelium and evaluated our findings in combination with the biochemical analysis of serum and yolk lipoproteins. Twenty-five to 30 nm-sized particles were demonstrated to be a principal element of the extracellular yolk mass and these were determined to be yolk very low density lipoprotein (VLDL). The particles were shown to be taken up by the epithelial cells via coated pits and engulfed by plasma membrane invaginations together with yolk subdroplets, another element of the yolk mass. Through apical vacuoles, the two yolk elements were incorporated into yolk drops, which were identified to be one of the lysosomal structures by a cytochemical procedure using acid phosphatase (AcP)ase activity. During the last week of incubation, which is the final third of the incubation period, the digestion seemed to progress rapidly in the yolk drops, which came to resemble lipolysosomes; lipoprotein production became active as expressed by an enlarged Golgi apparatus. The newly produced lipoprotein particles were electron-lucent and irregular in size (50-120 nm). They were sequestered in secretory vacuoles and secreted from the vascular surface of the epithelial cells. Finally, the particles were thought to be taken into the vitelline circulation as plasma lipoproteins. The major component of lipoprotein in serum was determined to be low density lipoprotein (LDL) and high density lipoprotein (HDL), while cholesterol content was found to increase during incubation. We concluded that endodermal epithelial cells participate the synthesis of plasma LDL and HDL. For this synthesis the cells probably apply lipids and apo-protein generated from yolk VLDL degradation.

Egress route of emulsified 20 centistokes silicone oil from anterior chamber of rabbit.

Silicone oil is used in recent clinical practice, however, it may cause adverse reactions in the eyes. When the high viscosity silicone oil is contaminated with low molecular weight silicone oil, the contamination may cause ocular toxicity or elevation of the intraocular pressure. To obtain information on the distribution of this preparation, emulsified 20 centistokes silicone oil was injected into the anterior chamber of rabbit eyes. The silicone oil droplets were visualized by light and electron microscopy by using oil soluble phthalocyanine blue. This copper containing dye remains in the tissue after removal of the silicone oil by organic solvents. Two and 4 weeks after an injection, the silicone emulsion was observed as numerous small vacuoles with blue precipitate at the margin of vacuoles within elongated trabecular endothelial cells, fibroblasts along the route of uveoscleral outflow and cells of the iris. Three hours after the injection, only a few vacuoles were present in these cells. These results demonstrated that the emulsified silicone oil leaves the anterior chamber through the conventional and unconventional routes. Phagocytosis by the trabecular endothelial cells and fibroblasts along the uveoscleral route caused an accumulation of the emulsified silicone oil in these cells. With chronic exposure to emulsified silicone oil, changes in the trabecular meshwork may lead to a reduction in the outflow of aqueous humor and cause glaucoma.

Immunohistochemical study of the post-natal development of the folliculo-stellate cells in the rat anterior pituitary gland.

We investigated the post-natal development of cell-to-cell communication within the rat anterior pituitary gland cells using immunohistochemistry of the S-100 protein. Tissues of animals from 10 to 60 days of age were analyzed. At 10 days of age, S-100 protein-containing cells were rarely observed. With age, the population of S-100 immunostained cells increased until day 40 when they were found to be quite numerous. No further changes were noted from day 40 through day 60. From our previous studies, we conclude that the cells which reacted with the S-100 antiserum were folliculo-stellate cells and their developmental pattern parallels that of the hypophyseal-gonadal axis.

Intercellular communication within the rat anterior pituitary gland: V. Changes in cell-to-cell communications as a function of the timing of castration in male rats.

Cell-to-cell communication by gap junctions was investigated in the male rat anterior pituitary gland following several experimental regimens involving castration. The regimens included the following animals: (1) Group 1, castrated at 10-day intervals from day 10 to 50 and sacrificed at 60 days of age; (2) Group 2, castrated every 10 days from days 10 to 50 and sacrificed 50 days after castration; (3) Group 3, castrated at 5 days of age and sacrificed every 10 days from day 10 to 60; or (4) Group 4, remained intact and sacrificed every 10 days from days 10 to 60. In all of the castrated animals, numerous so-called castration cells were scattered throughout the pars distalis of the pituitary gland, with occasional "signet ring cells" being observed. In Groups 1 and 2, the pattern of gap junction development and their number was no different from the intact control (Group 4). In contrast, the number of gap junctions in the animals castrated on day 5 remained very small even into adulthood. These data demonstrate that gonadal steroids are important in the initial development of gap junctions within the pituitary gland but are not necessary to sustain their presence once an animal becomes an adult.

Intercellular communication within the rat anterior pituitary gland: IV. Changes in cell-to-cell communications during pregnancy.

Cell-to-cell communication by gap junctions was investigated in the female rat anterior pituitary gland from 9 through 21 days of pregnancy and subsequently on days 2 and 20 of the lactational period. Compared with intact estrus females, the major morphological characteristics of the pituitary gland during pregnancy were remarkably developed prolactin cells and gonadotrophs. A close relationship of both cell types was clearly evident. Gap junctions were present at each of the time intervals studied; however, they were noted only between adjacent folliculo-stellate cells. No remarkable changes were noted in the number of gap junctions during the middle stage of pregnancy (day 9 through day 15), with the relative number resembling that found in intact, 90-day-old controls during estrus (0.47 +/- .01 junctions/follicle-control vs. 0.50 +/- 0.08--day 15 of pregnancy). In the later stages of pregnancy (day 17 through day 21), a demonstrable increase was observed (0.64 +/- 0.10--day 17, 0.79 +/- 0.11--day 19 and 0.72 +/- 0.12--day 21), whereas during the lactation, this pattern returned to that seen at midpregnancy. Since both prolactin and the gonadal steroid hormones dramatically fluctuate during pregnancy and lactation, it is postulated that they may have an active role in gap junction formation during these two phases of reproductive life.

Intercellular communication within the rat anterior pituitary gland. III. Postnatal development and periodic changes of cell-to-cell communications in female rats.

Cell-to-cell communication by gap junctions was investigated in the female rat anterior pituitary gland from 10 through 45 days of postnatal development and in 60-day-old animals. Gap junctions initially appeared between adjacent folliculo-stellate cells on day 25. Their appearance in female rats was 5 days later than that observed in males (Soji et al., 1990). Gap junction number increased until the animals became 40 days of age, when they reached a level that resembled that found in adults. In addition, a correlation was evident between the frequency of gap junctions and stages of the estrous cycle, where they were most numerous during either proestrus or estrus. These results along with those previously published suggest that gap junction formation within the female rat hypophysis is in part modulated by both gonadal steroid hormones as well as prolactin.

Experimental retinal tolerance to emulsified silicone oil.

Vitreous replacement by silicone oil has become increasingly popular in the treatment of severe and complicated retinal detachment. Several studies have suggested that silicone oil may be toxic to the retina or may stimulate periretinal proliferation. To better understand its effects, emulsified or nonemulsified silicone oil was injected into rabbit eyes that had undergone mechanical vitrectomy. Silicone oil was labeled with phthalocyanine blue to aid in histologic localization. Retinal changes were compared by light microscopy at 1, 4, and 12 weeks after intraocular injection. Emulsified silicone oil was found to penetrate the inner retina at 1 week and cause epiretinal membrane formation as early as 4 weeks after injection. Nonemulsified oil produced no histologic changes in the retina. No cytotoxic effects were observed in eyes treated with ether emulsified or nonemulsified silicone oil. It is concluded that emulsified silicone oil can both penetrate the retina and stimulate epiretinal membrane formation in the vitrectomized rabbit eye.

Cytochemistry of Ca(++)-dependent adenosine triphosphatase (Ca-ATPase) in rat anterior pituitary cells.

In the present study, we demonstrate the localization of Ca(++)-ATPase in the anterior pituitary of the male rat. Ca(++)-ATPase was mainly distributed on the membrane system of the granular cells, which included the plasma membrane, the outer mitochondrial membrane, the enveloping membrane of secretory granules, the smooth endoplasmic reticulum and some components of the Golgi complex. No reaction product was detected on the membrane of the rough endoplasmic reticulum or that surrounding the lysosomes. A positive reaction was clearly observed on the membranes surrounding 'large' secretory granules, while that present on the membranes of the 'small' granules was comparatively weak. The cells which contained the 'large' granules were interpreted as growth hormone-secreting cells and those in which the 'small' granules were located as gonadotrophs. There were either no reaction or one that was barely detectable on the plasma membrane of the folliculo-stellate cells. These data along with our previous findings (Soji, 1982, 1984) suggest that the membranous enzymes are not uniformly distributed over all pituitary cells but rather are specific for a given cell population(s).

Intercellular communication within the rat anterior pituitary gland. I. Postnatal development and changes after injection of luteinizing hormone-releasing hormone (LH-RH) or testosterone.

The postnatal development of gap junction formation and cell-to-cell communication were investigated in male rats from 10 through 40 days of age. These junctions initially appeared between adjacent folliculo-stellate cells on day 20. Their numbers increased until the animals reached the age of 40 days, when their frequency reached a level that resembled that found in adults. The ontogeny of these junctions was examined in rats treated with luteinizing hormone releasing hormone (LH-RH) or testosterone. The two hormones were injected for 1 week into rats aged 3, 13, 23, or 33 days. The appearance of gap junctions was accelerated in a similar fashion by LH-RH and testosterone, with their formation and numbers being advanced by 10 days over that observed in the untreated controls. The results suggest a role for the gonadal steroid hormones in the formation of gap junctions in the rat hypophysis.

Intercellular communication within the rat anterior pituitary gland. II. Castration effects and changes after injection of luteinizing hormone-releasing hormone (LH-RH) or testosterone.

This study investigated the relationship between gap junction formation and sex steroids in the male rat anterior pituitary gland. Animals were castrated at 5 days of age and separated into the following three groups: 1) oil-treated controls, 2) those injected with LH-RH, and 3) those given testosterone. On days 10, 20, 30, and 40, five rats in each group were sacrificed and their hypophyses removed for ultrastructural examination. When compared with age-matched, intact animals, there was a marked suppression in follicular development and in the number of gap junctions present in the pituitary glands of both the castrated controls as well as the castrates given luteinizing hormone releasing hormone (LH-RH). In contrast, the morphology of these structures in the animals given testosterone was indistinguishable from that observed in the intact controls. These observations provide more definitive evidence that in the male rat pituitary gland maturation of the structural organization of the follicles, including gap junction formation, requires an intact hypophyseal-gonadal axis and is highly dependent on the hormone testosterone.

Intercellular communication between rat anterior pituitary cells.

Cell-to-cell communication within the rat anterior pituitary was investigated in 60-day-old male rats with immunohistochemistry, scanning electron microscopy, freeze-fracture electron microscopy, and conventional transmission electron microscopy. A dense cytoreticular network of cytoplasmic processes from the folliculostellate cells was found to contain immunoreactive S-100 protein and was observed throughout the anterior pituitary. Nonimmunoreactive cells, which were granular, were situated in the center of each network. Almost all of the granulated cells were situated in close proximity to the folliculostellate cells. Scanning electron microscopy revealed that the gland consisted of microlobules enclosed by a basal lamina. On the surface of the microlobules were blood vessels whose branches invaded its internal structures. Cytoplasmic processes from folliculostellate cells projected outside the microlobule. Freeze-fracture electron microscopy demonstrated the presence of numerous intramembranous particles on the P-face of the plasma membrane. Scattered on the cell surface were groups of particles forming gap junctions. Meshworks of ridges which were representations of tight junctions were also observed near clusters of microvillous fragments. Clusters of particles forming small gap junctions were located between the meshworks of tight junctions. Small gap junctions were clearly observed by conventional electron microscopy between junctional complexes in a manner similar to that seen by freeze-fracture electron microscopy. Slender cytoplasmic processes of folliculostellate cells came in contact near the basal lamina and were adjoined by small gap junctions. The ratio of nongranular cells which contained gap junctions to those in which the junctions were absent was about 1:1. The size of the gap junctions ranged from 50 nm to 3 microns. No gap junctions were observed along the plasma membranes of the granular cells. The significance of an intercellular communication system within the anterior pituitary gland of the rat is to establish a mechanism for rapid transmission of information in an organ which lacks direct innervation.

[A case of neurilemmomatosis].

A 25-year-old man had multiple subcutaneous nodules on the neck, trunk and extremities. Those nodules first appeared in the right popliteal fossa about 15 years ago and thereafter gradually increased in the number with hearing loss, tinnitus, and vertigo. The tumors had smooth surfaces and were elastic hard without any adhesion to the overlying skin or to subcutaneous tissue. Histological examination revealed, in most parts of the lesion, Antoni type A neurilemmoma and the Antoni type B picture at the periphery. As extracutaneous lesion, there were bilateral cerebello-pontine angle neurilemmomas, and spinal and adrenal tumors. Similar subcutaneous tumors have been recognized in 6 of 17 family members of the previous four generations of his family. According to a statistical analysis of 119 cases, including this one, in the Japanese dermatological field, of 75 cases of solitary neurilemmoma and 44 cases of multiple ones, the latter showed male predominance and lower age of the onset. Many of them had tumors not only in the skin but also in extracutaneous sites.

Granulated 'marginal cell layer' in the rat anterior pituitary gland.

A granulated 'marginal layer cell' was observed in the lining of Rathke's residual pouch of 5 and 10 day-old rat anterior pituitary glands. Immunohistochemistry was not employed to identify the precise function of these cells. However, the cytological characteristics of nearly all of the cells indicated that they resembled GH-secreting cells, with a few displaying morphological features of corticotrophs. In pituitary glands of 5-20 day-old rats, both ends of Rathke's residual pouch extended into the pars distalis at the site of transitional zone of this lobe and of the pars intermedia. The cells within the 'invading' residual pouch contained numerous microvilli. In the middle portion of the residual pouch, cavities lined by 'marginal layer cells' had numerous microvilli and were adjoined by junctional complexes. In the adult rat pituitary gland, there were no granulated cells in the 'marginal cell layer' and no invasion of the residual pouch into the anterior lobe. From these data the possible source of the follicle and of the folliculo-stellate cells in the anterior pituitary of the rat is proposed.

Histochemical study of the rat anterior pituitary LH-gonadotroph after administration of luteinizing hormone releasing hormone (LH-RH).

The aim of this study was to identify the LH-gonadotroph, aided by histochemical demonstrations of adenylate cyclase and acid phosphatase activities in 60-day-old male rats, after a single 100 micrograms injection of luteinizing hormone-releasing hormone (LH-RH). The results obtained are as follows: 1) Separation of the lysosomes from the large secretion granules in the LH-gonadotroph was accomplished in order to demonstrate acid phosphatase, the marker enzyme of lysosomes. 2) The large granules in the LH-gonadotroph decreased remarkably in number within 5 min after LH-RH injection. 3) A marked and prolonged increase in adenylate cyclase activity was observed on the plasma membrane of the LH-gonadotroph after LH-RH injection; this increase continued up to 30 min. 4) At 60 min after LH-RH injection the small secretion granules began to decrease in number. 5) Losing the large granules due to the LH-RH treatment, the LH-gonadotroph resembled the FSH-gonadotroph. From these observations it appears that the FSH-gonadotroph is an immature or storage state LH-gonadotroph and that it changes from an LH-gonadotroph into an FSH-gonadotroph on the loss of its large secretion granules.