Toxicity and metabolism of monoethylhexyl phthalate and diethylhexyl phthalate: a survey of recent literature

The literature dealing with monoethylhexyl phthalate (MEHP), the principal metabolite of di (2-ethylhexyl) phthalate (DEHP), a widely used plasticizer, is discussed. MEHP has been shown to be moderately toxic and, following oral administration, undergoes omega- and omega- 1 oxidation to yield the same metabolites as does DEHP. In plasma there is an equilibrium between MEHP absorbed to albumin and in free solution, whereas DEHP is bound to lipoproteins. Studies involving orally administered MEHP revealed the mild hepatic changes occurred but there was no bioaccumulation of the monoester. Studies of the rat and rabbit indicated that MEHP has no teratogenic effects.

Cadmium-induced prostate metallothionein in the rabbit

Male rabbits injected with cadmium chloride (4 mg/kg) lead to the detection of a major metal-containing peak in the prostate cytosol. Chromatographic profiles indicate the presence of metallothionein (MT). MT is associated with zinc ion. The rabbit prostate, like that of other species, contains zinc-associated proteins, and this protein possesses many of the characteristics of metallothionein.

Interaction between prolactin and androgens in the accessory sex organs of male mice

Treatment of adult male mice with varying doses of prolactin increased the weights of the seminal vesicles and the anterior prostate gland. Only in the seminal vesicles were these increases in organ weights associated with increased levels of DNA. In castrated mice, prolactin alone failed to alter the weights of the accessory sex organs or DNA content. However, the simultaneous administration of prolactin and testosterone resulted in enhanced androgenic stimulation of seminal vesicle weights and their DNA content. Prostatic weights, but not DNA content, were augmented by treatment with prolactin and testosterone. Although the kidneys exhibited androgen sensitivity, prolactin failed to enhance the effect of testosterone upon the kidney. Augmentation of androgen action in the accessory sex organs was observed only after treatment with prolactin or growth hormone. Prolactin also enhanced the effects of dihydrotestosterone and 5 alpha-androstane-3 alpha, 17 beta-diol, but not of 5 alpha-androstane-3 beta, 17 beta-diol. These studies revealed that prolactin enhances the proliferative actions of androgens in mouse seminal vesicles, but not in the anterior prostate glands or the kidneys.

Effects of cyproterone acetate on growth and androgen metabolism of rat ventral prostate transplants

Cyproterone acetate (CA0 (10 or 20 mg kg-1 daily for 5 days) injected into castrate rats supplemented with testosterone propionate (TP) caused a significant decrease in ventral prostate weights in situ; no inhibitory effects were noted in transplant weights. CA failed to significantly inhibit DNA in either the in situ prostate or transplant, but his anti-androgen caused a significant decrease in the formation of 3H-dihydrotestosterone and 3H-androstanediol from radioactive testosterone in the in situ organ. Histologically, CA caused a decrease in epithelial cell secretory activity.

The analysis of lymphoid subpopulations in normal and malignant tissues by immunofluorescence techniques

Tissue sections of frozen biopsy specimens obtained from normal and hyperplastic human lymphoid tissues as well as 40 cases of non-Hodgkin's lymphomas were analysed in immunofluorescence tests (using red TRITC and green FITC double-labeling). A panel of antisera including well-characterized conventional reagents to immunoglobulin classes, T-lymphoid and Ia-like antigens and monoclonal antibodies, including the OKT range made by Ortho Laboratories, was used. The findings show that the immunological methods can give a very accurate analysis of the normal and malignant lymphoid cells and can provide complementary information to conventional histology. Furthermore, the monoclonal antibodies to well defined lymphocyte subsets can provide data which suggests (although does not prove) functional relationships between different types of cells in normal and malignant lymph nodes. Thus, the technology described fills the gap between conventional histology and cellular immunology.

Effects of prolactin on DNA synthesis and growth of the accessory sex organs in male mice

The role of PRL in the development of male accessory sex organs remains unresolved. In the present studies, the influence of PRL and testosterone upon DNA synthesis and cell proliferation was examined in the anterior prostate gland (AP) and the seminal vesicles (SV) of mice. Hormonal effects on DNA synthesis were evaluated by examining the in vitro incorporation of [3H]thymidine into DNA in relation to temporal alterations in tissue DNA content. In intact mice, PRL (300 IU/kg daily) produced peak stimulation of [3H]thymidine incorporation into DNA by SV after 3 days of treatment. In contrast, PRL failed to alter [3H]thymidine incorporation by the AP. Only in SV did PRL injections lead to elevated levels of tissue DNA. Injections of testosterone (0.75 or 7.5 mg/kg daily for 3 days) to castrated mice also produced significant stimulation of labeled thymidine incorporation into DNA by AP and SV. Concomitant injections of PRL (150 IU/kg) and testosterone (0.75 or 7.5 mg/kg) enhanced the stimulatory effects of this androgen on DNA synthesis and DNA content in the SV, but not in the AP. When PRL alone was administered to castrated mice, it failed to affect either [3H]thymidine incorporation into DNA by AP and SV or accessory sex organ weights and DNA contents. The results of these studies suggest that PRL enhances the effects of androgens upon DNA synthesis and growth of the seminal vesicles, but not of the anterior prostate glands of mice.

Investigation and control of an outbreaks of legionnaires' disease in a district general hospital

Between December, 1979, and July, 1980, 12 cases of legionnaires' disease were recognised in a district general hospital. 11 of the patients probably acquired their infection within the hospital. Epidemiological and environmental studies indicated that the plumbing system and possibly also the air-conditioning cooling-tower exhaust in the new building of the hospital were the sources of infection. Chlorination of the cold-water supply and raising the hot-water temperature appeared to terminate the outbreak.

The human thymic environment

Selected combinations of antisera labelled with different fluorochromes were used to explore the cellular interactions in the human thymic cortex and the medulla. In the early fetal thymus the cortical epithelial cells and an apparently more mobile medullary interdigitating cell population expressed large amounts of Ia-like (HLA-DR) and moderate amounts of HLA-A,B,C antigens while the lymphoid cells in the cortex expressed human T lymphocyte and cortical thymocyte antigens but were Ia-, HLA-A,B,C-. This arrangement is maintained in the infant thymus. The terminal deoxynucleotidyl transferase enzyme is first generated in cortical thymocytes (around the 17th week of gestation) and appears in bone marrow precursor cells later. In the infant thymus the lymphoid populations could be classified, according to their reactivity pattern with the new monoclonal antibodies of the OKT series, into three cell types: putative prothymocytes, typical cortical thymocytes and medullary thymocytes. Among the medullary population the majority showed the phenotype of the "inducer" cell and a minority showed that of "suppressor-cytotoxic" cells. The thymic medulla (and interdigitating cells in peripheral lymphoid organs) may predominantly contribute to the generation of "inducer" T lymphocytes.

Differential diagnosis of malignant lymphoma and nonlymphoid tumors using monoclonal anti-leucocyte antibody

Pathologic samples from 34 cases of human solid malignancies were tested for reactivity with monoclonal anti-human leucocyte antibody, designated 2D1. This antibody detects a human leucocyte antigen (HLe-I) that is expressed strongly on B and T lymphoid cells and weakly on early hemopoietic cells, but is not found on normal mesenchymal and epithelial tissues. This study demonstrates the use of this reagent in cryostat sections of tumor samples using indirect immunofluorescence in combination with other lymphoid markers such as anti-T cell serum, anti-Ia-like serum (detecting p28, 33 "B cell associated" membrane antigen) and antisera to different immunoglobulin isotypes. Tumor cells from all 12 cases of epithelial malignancies and sarcomas were HLe-I- although adjacent (normal) lymphoid cells showed strong positive staining. In contrast, 20 cases of lymphoma (B- as well as T-cell types) were HLe-I+. Two other malignancies involving the lymphoid system were HLe-I- and failed to express any of the other lymphoid markers tested.

Phosphorylation of heart glycogen synthase by cAMP-dependent protein kinase. Regulatory effects of ATP

Glycogen synthase I, purified from bovine heart, had a specific activity of 33 units/mg and gave a single band on sodium dodecyl sulfate gel electrophoresis with a subunit molecular weight of 86,000. The enzyme was phosphorylated with cAMP-dependent protein kinase catalytic subunit, also isolated from heart. With 10 microM ATP, only one phosphate group was incorporated per subunit of glycogen synthase. The phosphorylation decreased the per cent of glycogen synthase I from 0.95 to 0.50 when activity was determined by assays with Na2SO4 and glucose 6-phosphate. Glycogen synthase containing one phosphate per subunit was designated GS-1. One additional phosphate was incorporated per synthase subunit when ATP was increased to 0.5 mM and the percent glycogen synthase I decreased from 0.50 to < 0.05. This enzyme form was designated GS-1,2. Conversion of GS-1 to Gs-1,2 gave cooperative kinetics with ATP concentration and a half-maximal stimulation at approximately 40 microM. Phosphorylation of GS-1 could also be achieved by adding other non-substrate nucleotide triphosphates such as ITP and UTP along with 10 microM ATP. Glucose-6-P and Na2SO4 were without effect on this phosphorylation reaction. Two separate peptides were obtained after CNBr cleavage of 32P-labeled GS-1,2 and only one from GS-1. Both enzyme forms contained a single phosphorylated peptide in common. Thus, heart glycogen synthase may be phosphorylated specifically in either of two different sites using appropriate concentrations of ATP. ATP acts as a substrate for the protein kinase and also affects the availability of a second site to phosphorylation by cAMP-dependent protein kinase.