Effects of glucagon on the redox states of cytochromes in mitochondria in situ in perfused rat liver

The effects of glucagon on the respiratory function of mitochondria in situ were investigated in isolated perfused rat liver. Glucagon at the concentrations higher than 20 pM and cyclic AMP (75 microM) stimulated hepatic respiration, and shifted the redox state of pyridine nucleotide (NADH/NAD) in mitochondria in situ to a more reduced state as judged by organ fluorometry and beta-hydroxybutyrate/acetoacetate ratio. The organ spectrophotometric study revealed that glucagon and cyclic AMP induced the reduction of redox states of cytochromes a(a3), b and c+c1. Atractyloside (4 micrograms/ml) abolished the effects of glucagon on these parameters and gluconeogenesis from lactate. These observations suggest that glucagon increases the availability of substrates for mitochondrial respiration, and this alteration in mitochondrial function is crucial in enhancing gluconeogenesis.     

Patterns of cancer in geographic and endogamous subdivisions of the Hutterite Brethren of Canada

The Hutterite Brethren comprise a religious isolate and live on communal agricultural farms (colonies) in North America. In 1976 there were approximately 15,000 Canadian Brethren living in 179 colonies of the three endogamous subdivisions, the Dariusleut, Lehrerleut, and Schmiedeleut. Dariusleut and Lehrerleut colonies are located in both Alberta and Saskatchewan, and the Schmiedeleut are in Manitoba. Brethren were identified on population-based cancer registries of the three Prairie Provinces and among death registrations in the vital statistics of Alberta and Saskatchewan. The method of ascertainment was by a search for the 15 contemporary surnames and verification by address. 89 male and 91 female Brethren were identified who had cancer during the period, 1956--1975. The numbers of observed cancers were less than expected from provincial incidence rates for males and females in each province. The largest deficits were for female Brethren in Manitoba and Saskatchewan. There is a marked deficiency of cancer of the uterine cervix among female Brethren. In males there is a significant deficit of lung cancer. The Hutterite way of life contributes to a low risk for cancers of smoking-associated sites. However, there is evidence that male Brethren in Alberta may be at relatively increased risk for stomach cancer and leukemias. The site distribution patterns of cancers among the three endogamous leut are similar.     

The exchange hypothesis for the formation of chromatid aberrations: an experimental test using bleomycin

The association between bleomycin-induced chromatid aberrations and BUdR-label exchange between sister chromatids was investigated in order to evaluate Revell's exchange hypothesis for the formation of chromatid aberrations. The results of this study indicate that a larger than expected proportion of chromatid breaks can be accounted for by the exchange hypothesis though not all breaks are the result of incomplete exchange.     

Comparative effectiveness of lymphotoxin anticarcinogenic and tumor cell growth-inhibitory activities

Prevention of ultraviolet radiation- or chemical carcinogen-induced morphologic transformation and inhibition of tumor-producing transformed cell growth by lymphotoxin and by normal spleen leukocytes were quantitatively compared to define the antineoplastic activity spectra of these natural immune mediators. When Syrian golden hamster embryo cells seeded for colony formation in culture dishes were treated simultaneously with carcinogen and lymphotoxin, the number of morphologically transformed cell colonies was irreversibly reduced by 50% in the presence of 6 units of lymphotoxin/ml. Lymphotoxin inhibition of tumor cell growth, however, was reversible and 50% reduction in tumor cell growth in three transformed lines required 124, 330, and 477 units/ml. Thus, the anticarcinogenic activity of lymphotoxin can be 20-fold or more greater than its tumor growth-inhibitory activity. Similarly spleen leukocytes also were more effective as an anticarcinogen than as an inhibitor of tumor cell growth, consistent with previous observations that naturally occurring spleen leukocyte antineoplastic activity may result from lymphotoxin secretion.     

Presence of mast cell precursors in the yolk sac of mice

Concentration of mast-cell precursors in hematopoietic tissues of mouse embryos was evaluated by a limiting dilution method. Cells from yolk sacs, livers, and bodies of (WB x C57BL/6)F1 (hereafter called WBB6F1)- +/+ embryos were injected directly into the skin of adult WBB6F1-W/Wv mice which were genetically depleted of tissue mast cells. Concentration of mast-cell precursors was calculated from the proportion of injection sites at which mast cells did not appear. Since the concentration of mast-cell precursors in the yolk sac was about 30 times as great as that of embryonic body at Day 9.5 of the pregnancy, the mast-cell precursors seemed to be generated within the yolk sac. The concentration in the yolk sac reached the maximum level at Day 11, and then dropped markedly at Day 13. In contrast, mast-cell precursors increased from Day 11 to Day 15 in the fetal liver. As a result, the concentration of 11-day yolk sacs was comparable to that of 15-day fetal liver. Although intravenous injection of 15-day fetal liver cells (2 x 10(6)) rescued the general mast-cell depletion of WBB6F1-W/Wv mice, the intravenous injection of the same number of 11-day yolk sac cells did not rescue it. In contrast with fetal livers, yolk sacs scarcely contained hematopoietic stem cells which were measured by spleen colony formation. Therefore, the mast-cell precursors of the yolk sac may not originate from such stem cells.     

Computerized matching of relevés and association tables,with an application to the British National Vegetation Classification

When a new relevé is to be assigned to a pre-existing type, its composition is compared with an association table. Bayesian inference may seem a good way to make the comparison, but presents difficulties. In an alternative approach, three indices of goodness-of-fit are proposed. Compositional satisfaction is a measure of how well the species composition of the relevé fits the constancy classes in the table; it is a minor modification of the Czekanowski coefficient of similarity between observed and expected numbers of species in each constancy class. Dominance satisfaction is a modification of the Czekanowski similarity between the relevé and cover values that might be expected from the association table. Dominance constancy is a weighted mean of the constancy class of the four most abundant species in the relevé. A computer program, TABLEFIT, combines them into a single index. It has been tested on British mire vegetation.     

Assessment of Amyloid β Protein in Cerebrospinal Fluid as an Aid in the Diagnosis of Alzheimer's Disease

Abstract: The principal constituent of amyloid plaques found in the brains of individuals with Alzheimer's disease (AD) is a 39–42-amino-acid protein, amyloid β protein (Aβ). This study examined whether the measurement of Aβ levels in CSF has diagnostic value. There were 108 subjects enrolled in this prospective study: AD (n = 39), non-AD controls (dementing diseases/syndromes; n = 20), and other (n = 49). CSF was obtained by lumbar puncture, and Aβ concentrations were determined using a dual monoclonal antibody immunoradiometric sandwich assay. The mean Aβ value for the AD group (15.9 ± 6.8 ng/ml) was not significantly different from that for the non-AD control group (13.0 ± 7.1 ng/ml; p = 0.07), and substantial overlap in results were observed. Aβ values did not correlate with age ( r = −0.05, p = 0.59), severity of cognitive impairment ( r = 0.22, p = 0.21), or duration of AD symptoms ( r = 0.14, p = 0.45). These findings are in conflict with other reports in the literature; discrepant results could be due to the instability of Aβ in CSF. Aβ immunoreactivity decays rapidly under certain conditions, particularly multiple freeze/thaw cycles. Use of a stabilizing sample treatment buffer at the time of lumbar puncture allows storage of CSF without loss of Aβ reactivity. In conclusion, the total CSF Aβ level is not a useful marker for current diagnosis of AD.     

Ethanol Inhibits Basic Fibroblast Growth Factor-Mediated Proliferation of C6 Astrocytoma Cells

Abstract: Early ethanol exposure alters the proliferative activity of glial and neuronal precursors in the developing CNS. The present study tests the hypothesis that ethanol-induced alterations in cell proliferation result from interference with growth factors. An in vitro model of astroglia (C6 astrocytoma cells) was used to study the effects of ethanol on proliferation mediated by basic fibroblast growth factor (bFGF). bFGF stimulated the proliferation of C6 cells. This bFGF-enhanced proliferation was evident by increases in total cell number, DNA synthesis (as measured by [³H]thymidine incorporation), and the number of cells that took up bromodeoxyuridine. A synthetic peptide that specifically blocked the binding of bFGF to its high-affinity receptor completely abolished the proliferation-promoting effect of bFGF. The action of another mitogen for C6 cells, insulin-like growth factor-1, was not affected by this peptide. Therefore, the bFGF-stimulated proliferation was mediated through a specific bFGF receptor. Ethanol inhibited bFGF-mediated proliferation in a concentration-dependent manner. Ethanol concentrations of 100 and 200 mg/dl partially inhibited bFGF-mediated proliferation (by 58 and 74%, respectively), whereas concentrations of ≥400 mg/dl completely abolished the growth-stimulating effect of bFGF. Our data show that ethanol alters proliferative activity of C6 cells by disrupting the action of bFGF. The target of ethanol neurotoxicity is a receptor-mediated activity. bFGF can affect cell proliferation by a non-receptor-mediated intracellular pathway, but ethanol does not have an impact on this pathway.     

A preliminary report on the use of transfer factor for treating stage D3 hormone-unresponsive metastatic prostate cancer

As conventional treatments are unsuccessful, the survival rate of stage D3 prostate cancer patients is poor. Reports have suggested the existence of humoral and cell-mediated immunity (CMI) against prostate cancer tumour-associated antigens (TAA). These observations prompted us to treat stage D3 prostate cancer patients with an in vitro produced transfer factor (TF) able to transfer, in vitro and in vivo, CMI against bladder and prostate TAA. Fifty patients entered this study and received one intramuscular injection of 2–5 units of specific TF monthly. Follow-up, ranging from 1 to 9 years, showed that complete remission was achieved in 2 patients, partial remission in 6, and no progression of metastatic disease in 14. The median survival was 126 weeks, higher than the survival rates reported in the literature for patients of the same stage.     

Detachment of transformed cells

A parallel-plate flow chamber was used to quantify the detachment of normal cloned rat embryo fibroblasts (CREF) fibroblasts,ras-transformed CREF fibroblasts (CREF T24), and CREF T24 fibroblasts transfected with a Krev/RAP1A suppressor gene (HK B1) from a confluent monolayer of normal CREF fibroblasts to determine if the expression patterns of CD44 variants (mol wt 110 and 140 kDa) corresponded with detachment properties and metastatic potential. In the detachment assay, known shear stresses ranging from 20–24 dyn/cm² were applied to the adherent cells and the number of cells detached from the monolayer after 180 s was determined. Results showed that cellular expression of CD44 variants correlated with the metastatic potential of the cells and with the cells’ ability to detach from a monolayer of normal cells. Western blot analysis showed a low level of expression of the CD44 variants in the normal cell line, CREF, and the lowly metastatic cell line, HK B1. Detachment studies showed a low percentage of detachment of both of these cell lines from a normal cell monolayer. Tumor-derived (HK B1-T) and lung nodule-derived (HK B1-M) cell lines were established and both formed tumors and metastasis with reduced latency periods as compared to HK B1, but still showed a markedly delayed latency period compared to the highly metastatic cell line, CREF T24. Both of these cell lines showed a higher expression of the CD44 variants as compared to CREF and HK B1, and detached easier than CREF and HK B1. CREF T24 showed a much higher level of expression of the variants and had a higher percentage detachment than all other cell lines. To further test the role of the CD44 variants in the ability of the cells to detach from the normal monolayer, CREF cells were transfected with a DNA construct that constitutively expresses the CD44 variants and the detachment properties of three randomly selected clones were studied. Clones 2 and 3 showed a low level of expression of the CD44 variants after transfection and detached from the normal monolayer similar to CREF. Clone 1 showed a high level of expression of the CD44 variants and the detachment of these cells was significantly higher than CREF. From these results, it is concluded that in the five cell lines studied, expression of the CD44 variants play a significant role in the ability of the cells to detach from a monolayer of normal cells. It is hypothesized that this detachment may be an important component of a cell’s ability to metastasize.