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.     

Polycondensation-addition. V. Polyurethan-ureas with asymmetric carbon atoms in the main chain from L- and DL-2-alkyl-2-isocyanatoethyl chloroformates and diamines1

L - and DL-2-Alkyl-2-isocyanatoethyl chloroformates were synthesized by the phosgenation of the corresponding amino alcohols. These optically active or racemic difunctional compounds were submitted to polycondensation-addition with various diamines to form high molecular weight polyurethan-ureas having asymmetric carbon atoms along the main chain. The optically active polyurethan-ureas obtained had slightly higher melting points than the corresponding racemic polymers.     

Lyotropic mesophase of imogolite, 1. Effect of polydispersity on phase diagram

The acidic aqueous solution of imogolite is proposed to be an ideal lyotropic system. No temperature dependence was marked on the two phase boundary concentrations (A and B points) of imogolite solutions as predicted by the theories of Flory and Onsager. A satisfactory quantitative agreement was observed with Onsager's theory. The polydispersity of rod lengths was found to shift the A point towards lower concentrations than expected from theory.     

A rapid isolation technique of unmodified human T cells on a polystyrene resin column

An easy and rapid isolation technique of human T cells on a polystyrene resin particle column has been developed. The cells of the effluent fraction contained more than 90% sheep erythrocyte (SRBC) rosette-forming cells and less than 1% of cells bearing surface immunoglobulin (Ig) or peroxidase. The T cell (SRBC rosette-forming cells) recovery rate was 80%. The distribution of OKT antigen T cell subsets was essentially the same as that of T cells separated by rosette sedimentation. Cell functions such as tritiated thymidine uptake by T cells and helper activity in Ig production were also the same as that of T cells separated by SRBC rosette sedimentation. Natural killer-like activity of the T cells isolated by the present method increased more than that of T cells obtained by the conventional method. Moreover, it was free from functional modification which tends to result from stimulation such as by the SRBC antigen in the SRBC centrifugation method. The combination of a T cell population offered by the present method and B cells depleted of SRBC-binding B cells minimized background plaque formation and enabled us to quantify the plaque-forming cell number in an antigen-specific plaque-forming assay. Furthermore, these populations produced relatively pure interleukin 2 (IL 2) by stimulation of an autologous mixed lymphocyte reaction without any absorption of IL 2 produced in the same culture. It seemed to be useful to evaluate the ability of lymphocytes from normal individuals and patients to produce IL 2.     

The effect of prednisolone on substance P-induced vascular permeability in mice

The effect of prednisolone on the substance P (SP)-induced vascular permeability increase in male ddY, WBB6 F₁–+/+ (control) and WBB6 F₁-W/W^v (no mast cell in skin or internal organs) mice was investigated. 1) SP (1–10 000 pg/site) increased vascular permeability in ddY, WBB6 F₁–+/+ and WBB6 F₁-W/W^v mice ears. 2) SP (100 pg/site)-induced vascular permeability was inhibited by prednisolone (10 mg/kg) administered intraperitoneally 3 to 12 hours prior to the elicitation of the reaction in ddY mice. When dexamethasone at a dose of 1 mg/kg was administered intraperitoneally 2 to 24 hours prior to the elicitation of the reaction, significant inhibition was observed. When prednisolone was administered intraperitoneally 8 hours prior to the elicitation of the reaction, the SP-induced capillary permeability increase in both ddY and WBB6 F₁-W/W^v mice was clearly inhibited by the drug at doses of 5 and 10 mg/kg. 3) Diphenhydramine (1 and 10 mg/kg) inhibited SP-induced vascular reaction in ddY mice but not in WBB6 F₁-W/W^v mice. 4) Atropine (10 mg/kg) inhibited SP-induced vascular reaction in both ddY and WBB6 F₁-W/W^v mice. But acetylcholine did not cause an increase of vascular permeability in ddY and WBB6 F₁-W/W^v mice ears. 5) Prednisolone (5 mg/kg) inhibited histamine- and serotonin-induced vascular permeability in ddY and WBB6 F₁-W/W^v mice ears. 6) Prednisolone (5 and 10 mg/kg) inhibited the SP-induced histamine release from ddY mice peritoneal mast cells. These results suggest that the vascular effect of SP is mediated by both mast cell dependent (release of histamine from mast cells) and mast cell independent mechanisms. Prednisolone inhibits the SP-induced vascular permeability mediated by both mechanisms in mice.     

Coexistence of peptides (corticotropin releasing factor/neurotensin and substance P/somatostatin) in the bed nucleus of the stria terminalis and central amygdaloid nucleus of the rat

Coexistence of corticotropin releasing factor and neurotensin and also of substance P and somatostatin was demonstrated in the lateral bed nucleus of the stria terminalis and the central amygdaloid nucleus of the rat, by means of a light microscopic mirror method or immunofluorescent double staining. Using the former technique, a major proportion of corticotropin releasing factor-like immunoreactive cells were found to display neurotensin-like immunoreactivity in the dorsal subdivision of the lateral bed nucleus of the stria terminalis and the lateral subdivision of the central amygdaloid nucleus. On the other hand, the immunofluorescent method showed that a significant number of neurons with both substance P- and somatostatin-like immunoreactivity were located in the ventral subdivision of the lateral bed nucleus of the stria terminalis and the medial subdivision of the central amygdaloid nucleus. Distribution patterns of such co-localized peptides may indicate that there are morphological and biochemical similarities between the dorsal subdivision of the lateral bed nucleus of the stria terminalis and the lateral subdivision of the central amygdaloid nucleus, as well as between the ventral subdivision of the lateral bed nucleus of the stria terminalis and the medial subdivision of the central amygdaloid nucleus. Previous studies have demonstrated that peptide-containing neurons in the lateral bed nucleus of the stria terminalis and central amygdaloid nucleus, such as corticotropin releasing factor-, neurotensin-, substance P- and somatostatin-like immunoreactive cells, project to the lower brainstem. The results of the present study suggest that corticotropin releasing factor/neurotensin and substance P/somatostatin neurons may be part of the lateral bed nucleus of the stria terminalis/central amygdaloid nucleus-lower brainstem pathways.     

Proliferative cell nuclear antigen expression in follicular tumours of the thyroid with special reference to oxyphilic cell lesions

The expression of proliferative cell nuclear antigen (PCNA) in follicular tumours of the thyroid was examined by immunohistochemistry. Both usual nonoxyphilic cell follicular tumours (non-OCT) and oxyphilic cell tumours (OCT) were subdivided into benign, indeterminate, encapsulated carcinoma, and widely invasive carcinoma types. Among non-OCT the percentages of PCNA-positive cells in benign tumours, encapsulated carcinomas, and widely invasive carcinomas was 2.5%–8.6%, 11.8%–39.1%, and 18.6%–20.0%, respectively. There was a statistically significant difference between benign tumours and encapsulated or widely invasive carcinomas, as in previous studies. A value of 10% was appropriate to distinguish benign from malignant lesions. PCNA-positive cells in indeterminate-type non-OCT were not significantly different from those in benign tumours, ranging from 4.3%–19.6%, and occurring at more than 10% in three of six tuours. Among OCT the positivity was less than 10% in benign tumours (4.5%–7.8%) and more than 10% in malignant tumours (14.1%–35.9%) and all the eight indeterminate tumours (12.5%–27.3%), with a statistically significant differences between the benign tumour and each of the latter types. These results indicate that the examination of PCNA is valuable in diagnosis of thyroid follicular tumours and that the use of similar diagnostic criteria may be warranted in both non-OCT and OCT.     

A new gene encoding tRNAPro (GGG) is present in the chloroplast genome of black pine: a compilation of 32 tRNA genes from black pine chloroplasts

The chloroplast genome of black pine (Pinus thumbergii), a gymnosperm, contains 32 different tRNA genes, 30 of which correspond to those previously identified in tobacco and rice chloroplast genomes. Two additional genes encode tRNA^Pro (GGG) and tRNA^Arg (CCG); the former is newly identified while the latter is present in liverwort, Physcomitrella patens and Angiopteris lygodiifolia, chloroplast genomes. Moreover, a partial copy of the split tRNA^Gly (UCC) gene and full copies of tRNA^His (GUG), tRNA^Thr (GGU) and tRNA^Ser (GCU) genes are present in the large single-copy region of the genome, suggesting extensive rearrangements of the chloroplast genome during evolutio. No tRNA genes whose tRNA products can recognize codons CUU/C (Leu) and GCU/C (Ala) have been found. We propose that the 32 tRNAs are sufficient to read all the 61 sense codons in the black pine system using the two-out-of-three and the U:N wobble mechanisms.