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Five childhood malignant ectomesenchymomas are reported from three centers in three countries. The children were all younger than 3 years (four less than 12 months), four were boys, and four tumors were sited in the pelvis or external genitalia. All tumors had distinctive light microscopic features of rhabdomyosarcoma and three also demonstrated small numbers of included neuronal cells. Immunohistochemical studies and transmission electron microscopy revealed the additional presence of neurogenic components in the remaining two patients. An additional epithelial component was found by immunohistochemistry in one tumor, which suggests a pluripotential origin that still requires karyotypic investigation. Aggressive chemotherapy and adequate surgical excision have thus far been effective in providing disease-free follow-up for periods of 7 to 50 months. It is implied that because the biological behavior and morphology closely resemble those of rhabdomyosarcoma and because the neurogenic component is often in...

Lidocaine is administered to assess donor or recipient liver function during hepatic transplantation. This study was performed to determine whether lidocaine administered at a constant concentration affected hepatic function or had demonstrable effects on hepatocellular ultrastructure. Fourteen pigs were randomly allocated to receive either a two-stage infusion of lidocaine hydrochloride or of saline. Transhepatic blood samples were taken and ultrasonic portal venous and hepatic arterial blood flow readings made on animals anesthetized with isoflurane in nitrous oxide. Liver biopsies were taken for histological analysis and determination of adenine nucleotide status prior to and after 2 hr of the two-stage infusion. A mean systemic constant plasma lidocaine concentration of 5.9 micrograms/ml was achieved during the second hour of infusion. There were no differences between the two groups in a large number of indices of hepatic function and plasma composition prior to and during the second hour of the respective infusions. Hepatic blood flow was also similar at these times. On histological examination there were no electron microscopic changes that could be specifically attributed to the administration of lidocaine. However, there were progressive changes with time. This study suggests that in anesthetized pigs a constant lidocaine concentration of about 6 micrograms/ml has no detrimental effect on hepatic function. Progressive hepatic ultrastructural changes occurred that could not be attributed to the administration of lidocaine. These may be the result of anesthetic administered or the surgery performed.

Two fatal childhood cases of the rare pulmonary blastoma are reported. One was associated with a congenital cystic adenomatoid malformation. Both neoplasms extended to involve visceral pleura and were entirely composed of blastemal and mesenchymal elements without recognizable neoplastic epithelial components. The mesenchymal component in both instances consisted of malignant rhabdomyoblasts, undifferentiated mesenchyme, and differentiated, apparently benign, cartilage. Review of the literature suggests that these features may be specific for the childhood forms of pulmonary blastoma. It is further suggested that pulmonary blastoma, malignant mesenchymoma of the lung, and primary pulmonary rhabdomyosarcoma may have a common pathogenetic origin.

A simple and rapid method of processing ethylene-diamine-tetra-acetic acid anticoagulated peripheral blood or aspirated bone marrow for electron microscopy is described. The resultant buffy coat pellet is easily processed into epoxy resin. Semithin sections (1 mu) stained with 1% toluidine blue reveal the various stratified cell layers allowing convenient selection for ultramicrotomy and ultrastructural evaluation.

The monoclonal antibody, mAb3C4, raised against sonicated Mycobacterium bovis (Mb) BCG (Tokyo strain 172) cells recognises a 23-kDa protein in the cell wall. The gene encoding this protein was cloned and sequenced and found to be 100% homologous to mpb83 and mpt83 and the putative protein to have a 76% sequence similarity to the secreted, Mb-specific protein, MPB70. MPB83 contains the amino acid (aa) sequence LAGC, which corresponds to the consensus sequence for bacterial lipoprotein modification and processing. MPB83 associated with the detergent phase when separated with Triton X-114 confirming that it is a lipoprotein. When the putative site of acylation, the Cys in the sequence LAGC, was substituted with Ser, the mutated MPB83 associated with the aqueous phase. The cloned gene was used to determine the distribution of mpb83 in various Mycobacterium species. The gene was present in the M. tuberculosis (Mt) complex organisms, as well as in M. kansasii. In addition, Southern blot analysis of Mb and Mt DNA indicated that the mpb83 and mpb70 genes are located close to each other on the genome. Western blot analysis of cell lysates of various Mycobacterium species indicated that only Mt H37Rv and H37Ra produced proteins which reacted with mAb3C4. Furthermore, only two out of six of the Mb field isolates produced detectable antigen, indicating that expression of the mpb83 gene is variable within the Mt complex organisms.

A case of Pearson's marrow-pancreas syndrome is presented. The dominant clinical feature was a generalized disorder of proximal tubule function with severe renal magnesium wasting. Renal and muscle biopsies were performed and showed bizarre giant mitochondria.

Mucosal-associated lymphoid tissue (MALT) is a specialized form of peripheral lymphoid tissue which is found in mucosal surfaces directly or indirectly exposed to the environment. Using immunohistological labeling techniques and electron microscopy, we have explored the possibility that MALT exists in the normal fallopian tube. Immunohistological analysis has demonstrated a striking degree of uniformity in the phenotype of intraepithelial lymphocytes with a predominance of T-lymphocytes of T-cytotoxic/suppressor subtype. Occasional intraepithelial macrophages are also present, but B-cells, T-helper cells, and natural killer cells are absent or are rarely found in the epithelium. Electron microscopy has provided morphological evidence of an interaction between epithelial cells and intraepithelial lymphocytes. The opposing plasma membranes of these two cell types are arranged in the form of complex interdigitations and laminations. These striking arrangements substantially increase the total area of contact between the two cell types. We conclude that MALT does exist in the fallopian tube and that epithelial cells form an integral part of the system. A hypothetical view of the relationship between these cell types is presented.