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The activity and the affinity for concanavalin A-Sepharose (Con A) of liver gamma-glutamyltransferase (gamma GT) were investigated in man, under various clinical conditions and in rats during experimental hepatocarcinogenesis. In man, gamma GT activity was higher than normal in hepatomas and (except for 1 case of hemochromatosis) also higher in the surrounding cirrhotic liver. The proportion of gamma GT which did not bind to Con A (Con A- form) was also increased in the tumors and in the surrounding liver, yet (with the same exception as above) to a greater extent in the hepatomas. In rat, gamma GT activity was higher in fetal liver (15-fold) and in hepatocarcinomas (10-fold) than in normal adult liver; total liver gamma GT activity gradually increased during progression from foci of altered cells to neoplastic nodules and tumors. The proportion of the Con A- form of gamma GT in the early or late stage of the carcinogenic process did not significantly differ from that in normal adult or regenerating rat liver, i.e. about 20% of the total activity. By contrast, nearly all the gamma GT from fetal rat liver bound to Con A. This suggests that gamma GT expression in rat liver carcinoma does not correspond to so-called retrodifferentiation process.

By means of X-ray powder diffraction (XRD), octacalcium phosphate (OCP, Ca8H2(PO4)6 X 5H2O, Ca/P = 1.33) has been shown to be a metastable precursor of hydroxyapatite (HA, Ca10(PO4)6(OH)2, Ca/P = 1.67) during de novo HA formation in aqueous solutions containing [CaCl2] = 1.0-2.0 mM and [Na2HPO4] less than or equal to 3 mM, kept at 37 degrees C, 300 mosM and stirred gently at 150 rpm. At the precipitation boundary with initial pH = 7.4, OCP is stable for at least 24 hours when [Ca] = 1.0 mM, and is less stable when [Ca] = 2.0 mM, transforming into a mixture of OCP and HA within 24 hours. Almost complete transformation to HA within 24 hours takes place with high [Ca] and high [Pi]. Statistical analysis of the pH 7.4 precipitation boundary data supports the XRD findings: although [Ca][Pi] values vary significantly (P less than 0.001) with [Ca] (2.70 +/- 0.05 mM2 for [Ca] = 1.0 mM and 2.00 +/- 0.10 mM2 for [Ca] = 2.0 mM), [Ca]1.33[Pi] values do not vary with [Ca] suggesting that the initial precipitation process is 6(1.33 Ca + Pi)----OCP. With initial pH = 7.6, a different precipitation boundary with lower [Ca][Pi] values has been determined. These findings strongly support the fact that rat epiphyseal cartilage fluid which has [CaUF][PiUF] = 2.6 mM2 (UF = ultrafiltrate) and pH 7.6 [2] should be able to support de novo calcification.

To test the hypothesis that deficiencies in hypothalamic-pituitary function in genetic hemochromatosis result from cellular injury by iron deposits, we conducted provocative tests in 11 men with genetic hemochromatosis before and after iron depletion by serial phlebotomy and in 10 control subjects. We gave combination intravenous injections of insulin (0.15 U/kg), luteinizing hormone releasing hormone (LHRH, 100 micrograms), and thyrotropin releasing hormone (400 micrograms) and then measured plasma glucose, growth hormone, corticosteroids, follicle-stimulating hormone, luteinizing hormone, prolactin, and thyroid-stimulating hormone at 30-minute intervals for 90 minutes. Phlebotomy caused a substantial decrease in median values for serum ferritin, deferoxamine-chelatable iron, and hepatic iron concentration. Before phlebotomy, stimulation by hypoglycemia and thyrotropin releasing hormone caused significantly less secretion of growth hormone (P = 0.004) and prolactin (P = 0.03) in patients than in control subjects. No significant improvement was noted, however, in growth hormone or prolactin secretion after phlebotomy. Of the 11 patients, 7 had secondary hypogonadism, and phlebotomy did not improve the serum testosterone, follicle-stimulating hormone, luteinizing hormone, or responses to LHRH in any case. Chlorpromazine injections failed to elevate serum prolactin in all patients, and administration of levodopa caused a partial reduction in serum prolactin; thus, the hypothalamus may be an important locus of endocrine malfunction in these patients. We conclude that abnormal hypothalamic-pituitary function in genetic hemochromatosis is not substantially improved by iron-depletion therapy.

A study was carried out to determine the usefulness of erythrocyte ferritin analysis in identifying homozygotes and heterozygotes in families affected with hereditary hemochromatosis, an autosomal recessive disorder. To select the subjects the genotypes of 60 people from 26 affected families were determined by HLA-A and HLA-B haplotyping. In addition, data for 12 homozygotes for whom erythrocyte ferritin values were available from the literature were included. Likelihood analysis was used to evaluate the diagnostic value of erythrocyte ferritin analysis alone and in combination with serum ferritin testing. An erythrocyte ferritin value of 150 ag/cell or higher combined with a serum ferritin level above the 90th percentile indicated homozygosity, whereas a value of less than 150 ag/cell and a serum ferritin level at or below the 90th percentile indicated that homozygosity could be ruled out with a high degree of confidence. The probability of heterozygosity rose to 92% when the erythrocyte ferritin value was between 29 and 149 ag/cell and to 98% when this result was combined with a serum ferritin level at or below the 90th percentile. Erythrocyte ferritin analysis in combination with serum ferritin testing is useful for identifying homozygotes and a proportion of heterozygotes in families affected with hemochromatosis.

A 56-year-old man, who had previously been treated for arthritis of the hands, was admitted to the hospital because of abdominal pain and fever. Physical examination, laboratory tests and liver biopsy led to the diagnosis of hemochromatosis. The patient's brother, who had also been treated for arthritis, was then found to have hemochromatosis. The patient's five children appeared to be well, but serum iron studies and HLA typing showed that four were affected with hemochromatosis.

This study was designed to test the hypothesis that a hemochromatosis allele is implicated in the expression of porphyria cutanea tarda. HLA phenotypes were determined in 69 porphyria cutanea tarda patients, 42 of which had the sporadic type (normal erythrocyte uroporphyrinogen decarboxylase activity) and 27 unrelated patients who had the familial type (diminished erythrocyte uroporphyrinogen decarboxylase activity). The incidence of HLA antigen A3, a marker of the hemochromatosis allele, was identical in the sporadic patients (23.8%), in the familial patients (22.2%), and in the controls (24.5%). Furthermore, no clinical difference could be found between A3 and non-A3 patients. These results demonstrate no systematic association between hemochromatosis and porphyria cutanea tarda in the population studied. Another HLA-linked gene, however, could be implicated in the expression of the disease as HLA antigen DR7 presented an incidence statistically different (p less than 0.05) between sporadic (16.6%) and familial patients (43%).

We have mapped the transcription start sites of three petunia rbcS genes and reassayed the relative expression levels of the petunia rbcS genes using the technique of primer extension. This analysis was performed specifically to address the confusion in the literature concerning the relative expression levels of the two petunia rbcS genes, SSU301 and SSU11A. The primer extension analysis reported here confirms our previous results, specifically that the rbcS gene, which we term SSU301, gives significantly higher levels of steady state RNA than any of the other rbcS genes in leaf tissue from 10 week old petunia plants.

Estrogen receptor content of 8 cell lines from non-malignant human breast tissues was determined by an immunocytochemical assay using the Abbott ER-ICA monoclonal kit. The results were in accordance with those obtained by the conventional radiochemical (DCC) assay. Primary cultures of breast tissues are suggested as an important field for in situ application of the ER-ICA.