"Desmoplastic" versus "classic" medulloblastoma: comparison of DNA content, histopathology and differentiation.

A microfluorometric analysis was performed to analyse the DNA content of 42 medulloblastomas (MBs) and to seek correlations, if any existed, between the DNA distribution and ploidy values, neoplasm types (i.e. classic vs desmoplastic), histological features of aggressiveness, and immunocytochemical features indicating glial and/or neuronal differentiation. Thirty-one cases were classified as classic and 11 cases as desmoplastic MBs. Ten of 11 desmoplastic MBs had a near-diploid main mode and the remaining 1 case had a near-tetraploid main mode. Moreover, 10 of 11 (90%) cases showed a "monomodal" DNA distribution diagram. All these cases showed a uniform histology. In contrast, classic MBs represented a heterogeneous group of neoplasms. Twenty-two cases were near-diploid, 5 cases were near-tetraploid and 3 cases were near-triploid. The histogram type distribution showed a similar heterogeneity. Twelve of 31 (39%) cases had a monomodal histogram, 12 (39%) cases had a bimodal diagram and 7 (22%) cases a complex DNA distribution. There was a statistically significant difference (P less than 0.001) in terms of prevalence of DNA monomodal histograms between classic and desmoplastic MBs. Significant correlations were not observed among classic MBs between histological features of aggressiveness, type and degree of differentiation and DNA distribution. The present study indicates that desmoplastic MBs represent a homogeneous group of neoplasms in terms of histology and DNA distribution. In contrast, classic MBs are lesions with different degrees of histologically apparent aggressiveness and a complex DNA distribution.

Gastric choriocarcinoma; an immunohistochemical study.

A case is reported of primary gastric choriocarcinoma occurring in a 73-year-old man, associated with a high serum level of beta hCG. Both primary and lymph node metastases contained exclusively cyto and syncytiotrophoblastic elements. Immunohistochemical localization of chorionic gonadotropin (hCG), placental lactogen (hPL) and pregnancy-specific glycoprotein (SP 1) is described in relation to cytotrophoblastic differentiation. An intramucosal focus of adenocarcinoma supports the hypothesis of the origin of choriocarcinoma from usual gastric cancer.

FC receptor for IgM: factors influencing detection on human T lymphocytes.

This paper is concerned with technical standardization in detecting Fc-IgM receptors on human T lymphocytes. We have investigated a number of factors of critical importance in obtaining easily reproducible and reliable estimates of the numbers of TM cells among human peripheral T lymphocytes. A point of major importance is optimal coating of erythrocytes by IgM molecules. For this condition to be met, particular attention is required when erythrocytes from animals other than the one used for obtaining antiserum are used to prepare EA-IgM. Determination of the agglutinating titer of IgM preparation is useful in determing optimal sensitizing dilutions. Full expression of Fc receptors is favoured when human cord serum is added to the medium. The influence of incubation period of EA-lymphocytes mixtures on TM counts has also been investigated.

Echinococcus granulosus: specific quantification of the two most immunoreactive antigens in hydatid fluids.

Preparations of the two most immunoreactive Echinococcus granulosus antigens (antigens 4 and 5) from sheep hydatid fluid, purified by a simplified method, and monospecific antisera against antigens 4 and 5, prepared by a new procedure, were used to measure the antigenic concentrations of antigens 4 and 5 in swine, sheep, and human hydatid fluids from pulmonary or hepatic cysts. Two bovine samples and two commercial preparations were also tested. The concentration of both antigens was significantly higher in sheep and human hydatid fluids than in swine hydatid fluid. The antigenic content of the two bovine samples and of the two commercial preparations was below the sensitivity level of the method employed. Independently of the species tested, the amount of Echinococcus antigens was greater in hepatic than in pulmonary cysts. The ratio between the concentrations of antigens 4 and 5 was constant at about 1:10 in the samples from various organs and from different species. When there were enough samples for statistical analysis a linear correlation was found between the contents of these two antigenic components but there was none between the amounts of proteins and the antigenic concentrations in the single cysts. Sheep hydatid fluid must therefore be considered the best source of antigenic material for diagnostic purposes even though in human cysts the antigenic fraction is less contaminated by serum proteins. We describe a reliable method of standardising antigenic material for the immunodiagnosis of hydatid disease.

Alpha-1-antitrypsin in umbilical cord serum: pi phenotypes and relationships with idiopathic respiratory distress syndrome.

The concentrations and phenotypes of serum alpha-1-antitrypsin (alpha1AT) were determined in 650 newborn infants. The distribution of these 650 subjects among the various Pi phenotypes confirms the higher frequency reported for the PiS allele in Latin populations. Serum alpha1AT levels vary between one phenotype and the other. Besides, at birth, infants weighing more than 2,500 g have alpha1AT levels significantly higher (P less than 0.001) than infants weighing less than 2,500 g; this difference in serum alpha1AT concentrations is due to the low alpha1AT levels found in preterm infants. The significantly lower alpha1AT concentrations found in preterms is associated with a higher risk of developing IRDS and with a mean birth weight under 2,000 g. Infants who develop IRDS frequently have lower alpha1AT levels than those who do not develop the syndrome, independently from body weight. On the basis of serum alpha1AT quantitation, newborn infants may be separated into two groups, characterized respectively by concentrations above or below 150 mg%. From our data, it appears that if the group with an alpha1AT concentration lower than 150 mg% is phenotyped, it is possible to differentiate infants with a high risk of fatal IRDS from individuals with a "pathological" phenotype.

Echinococcus granulosus: identification of subunits of the major antigens.

This paper describes a procedure for obtaining the two "major" Echinococcus granulosa antigens (antigens 4 and 5) from sheep hydatid fluid. Purified antigen 4 (m.w. 400,000 and over) and antigens 5 (m.w. 150,000) were separated in order to identify molecular subunits of each. SDS 12.5% polyacrylamide gel electrophoresis of antigen 4 gave a single band for which a m.w. of 67,000 was calculated. When 5% 2-mercaptoethanol was added to the antigen 4 preparation, SDS 12.5% polyacrylamide gel electrophoresis gave two bands (m.w. 47,000 and 20,000). SDS 12.5% polyacrylamide electrophoresis of antigen 5, with or without 2-mercaptoethanol, gave at least three bands with m.w. ranging from 10,500 to 20,000. Low m.w. subunits of both antigens were eluted in a single peak from a preparatory SDS 7.5% acrylamide gel electrophoresis; these subunits were found to be immunogenic and antigenic.

Isolation of the most immunoreactive antigenes of echinococcus granulosus from sheep hydatid fluid.

This paper describes a simplified procedure for obtaining purified Echinococcus granulosus antigens from sheep hydatid fluid by using affinity chromatography on concanavalin A-Sepharose. The presence of two "major" antigens (4 and 5) was confirmed. Antigen 5 was isolated by preparative polyacrylamide gel electrophoresis. Antigen 4, eluted by diffusion from the gel, was seen to be "contaminated" by antigen 5 and was isolated by using anti-5 Sepharose-linked serum. These two major antigens were then tested separately against the sera of hydatidosis patients by using very simple immunolgic tests. The best results were obtained in passive hemagglutination with antigen 4. Antigen 4 is the most immunoreactive parasitic antigen; antibodies against it were found in the sera of all hydatidosis patients showing positive reaction. Apart from the direct use of this antigen in serologic tests, it appears possible to standarize the most frequently used and commerically available antigenic materials by titrating this component.