Enzymatic and immunologic study of the role of the thyroid hormone in the formation of the internal mitochondrial membrane during postnatal development of the rat

Hypothyroidism induces an increase of liver D-beta-hydroxybutyrate dehydrogenase activity. Injection of thyroid hormone reverses the phenomena. The use of monospecific antibody raised against the purified enzyme indicates that there was not an increase of apoenzyme biosynthesis. The thyroid hormone negative control is due to a metabolism alteration of the membrane phospholipids which are directly involved in the apoenzyme activity. The highest difference is observed with 20 days old rats. Opposite effects were obtained on succinate cytochrome c reductase.     

Properties of peroxisomes and their induction by clofibrate in normal adult rat hepatocytes in primary culture

Alterations in peroxisomes and catalase activity and their responsiveness to clofibrate in adult rat hepatocytes in primary culture were investigated. The numbers of peroxisomes with and without crystalloid nucleotids per unit cytoplasmic area were preserved in cultured hepatocytes for 2 d after seeding at a level comparable to that of freshly isolated hepatocytes. At Day 3 in culture, the number of anucleoid peroxisomes was reduced in untreated hepatocytes, accompanied by more significant reduction in the number of nucleoid-containing peroxisomes, which decreased until Day 5. Peroxisome diameters were reduced in untreated hepatocytes at Day 2 and this decrease in the diameter was continued until Day 7. Catalase activity in untreated hepatocytes decreased markedly with culture age. The number of anucleoid peroxisomes was significantly greater in hepatocytes treated with 2 mM clofibrate in culture than in freshly isolated hepatocytes for 2 d or in untreated hepatocytes of the same culture age through 7 d. The number of nucleoid-containing peroxisomes in the treated cells began to decrease in 3 d, but was greater than that of untreated cells at Days 3 and 5. Peroxisomes with well-developed nucleoids were observed frequently in the treated cells even at Day 7. Peroxisome diameters were greater in the treated cells than in untreated cells at Days 3, 5, and 7. Catalase activity was always higher in the treated cells than in untreated cells. These results suggest that clofibrate is effective in inducing peroxisome proliferation as well as in maintaining the organelles in cultured hepatocytes.     

Interaction between histamine and vagal stimulation on tracheal smooth muscle in dogs

We examined the interaction between histamine and vagal efferent activity on airway smooth muscle reactivity in 11 anesthetized vagotomized dogs using an isolated closed segment of the intrathoracic trachea filled with Tyrode solution under an isovolumetric condition. Intratracheal pressure change was measured as an index of tracheal smooth muscle tone. The administration into the tracheal segment of histamine (0.1 or 1.0 mg/ml) in six dogs and methacholine chloride (0.001 or 0.01 mg/ml) in the other five dogs elevated intratracheal pressure by about 5 cmH2O. The electrical stimulation of the peripheral ends of both of the cut cervical vagus nerves in the presence of histamine produced significantly greater responses than the additive responses of these two stimuli applied individually (two-way analysis of variance, P less than 0.025). However, the combined effects of vagal stimulation and methacholine were not significantly different from the additive responses of these two stimuli applied individually. The average values of intratracheal pressure elevated by the combined effects of vagal stimulation and histamine were significantly higher than those obtained by the combination of vagal stimulation and methacholine (two-way analysis of variance, P less than 0.01). This suggests that histamine potentiates tracheal smooth muscle reactivity to electrical vagal stimulation, which may contribute to the hyperreactivity observed in patients with asthma.     

Unique nature of an attenuated strain of tobacco mosaic virus: autoregulation

An attenuated strain L11A of tobacco mosaic virus (TMV) multiplied like wild type strain L at an early stage of infection in tomato leaves. Four days after inoculation, however, multiplication of L11A was drastically reduced (autoregulation) compared with the constant multiplication of L. In mixed infections, L11A strongly inhibited the multiplication of homologous strain L. Experiments with cucumber mosaic virus (CMV) or tobacco plants revealed that the inhibitory mechanism of L11A is not host-specific but virus-specific, and the autoregulatory mechanism is effective only for TMV. RNA synthesis in L11A infected leaves 4 days after inoculation was studied by polyacrylamide gel electrophoresis. Synthesis of TMV-RNA and its replicative intermediate were strongly inhibited, whereas the replicative form of TMV-RNA and ribosomal RNA were synthesized as in the case of L infection. Synthesis of non-coat-protein was studied by the incorporation of radioactive histidine into subcellular fractions derived from leaves infected with L or L11A for 4 days. Different patterns of the two strains in protein synthesis were noted. At least three proteins were predominantly synthesized in L11A infection. One of them was observed in the mitochondria fraction. From its position in polyacrylamide gel, it could be viral coded 165K protein which is considered to be involved in viral RNA replication. These results suggest that the unique nature of attenuated virus L11A, i.e. autoregulation, resulted from the inhibitory mechanism of viral RNA synthesis due to overproduction of 165K protein and is quite distinct from interferon, intrinsic interference or interference by defective virus.     

Adjuvant treatment with polyadenylic-polyuridylic acid in operable breast cancer: updated results of a randomised trial.

The results of a randomised trial of polyadenylic-polyuridylic acid given as adjuvant treatment for operable breast cancer were reviewed after a mean follow up period of 87 months. Of the 300 patients included in the original trial, 145 had been allocated to conventional treatment alone and served as controls. At the time of review the overall survival of the group given polyadenylic-polyuridylic acid was significantly improved (p less than 0.05) as compared with that of the controls given conventional treatment alone. Significant benefit (p less than 0.02) was also observed among patients with evidence of disease in lymph nodes, the best results occurring in those with up to three invaded nodes, who showed a significant increase in both overall and relapse free survival. No evidence of toxicity was recorded. These findings confirm the value of polyadenylic-polyuridylic acid as adjuvant treatment for operable breast cancer. Results in an experimental model and in patients receiving the adjuvant suggested a possible role of interferon and natural killer (NK) cells in the mechanism of action.     

Rapid and early determination of sex using trophoblast biopsy specimens and Y chromosome specific DNA probes.

The feasibility of determining sex by analysing deoxyribonucleic acid (DNA) with two probes specific for Y chromosomes was shown using DNA obtained from samples of blood from 30 non-related males and females of different ethnic origin. The DNA was spotted on nitrocellulose filters and hybridised with both a repetitive (P1) and a unique (49f) sequence specific for the human Y chromosome. A strong positive signal with both probes indicated the presence of male DNA. The sex of 12 fetuses was then similarly determined by molecular characterisation of DNA from trophoblast biopsy specimens. Chorionic samples were obtained in seven cases before termination of pregnancy in the first trimester and the aborted embryos subjected to karyotyping and sex chromatin analysis. In the five other cases samples were obtained from placentas obtained during caesarean section. Results of hybridisation were compared with those from cytogenic studies and actual sex at birth. The sex of all 12 fetuses was determined correctly by hybridisation.     

Effect of treatment with the MER tubercle bacillus fraction on syngeneic plasma cell tumors of BALB/c mice

Summary MER administered prophylactically prolonged the survival of BALB/c mice challenged with transplants of syngeneic plasmacytomas to a moderate but significant extent. In contrast, MER exerted little therapeutic action when given alone at or after tumor implantation.Combined treatment, with MER introduced prophylactically and cyclophopshamide (CY) after tumor implantation, decreased the incidence of recurrence of one of the tumors tested (MPC-11 NP, a non-myeloma protein producer) and prolonged host survival significantly as compared with animals subjected to CY therapy alone. When, instead, MER was introduced at the time of tumor challenge or thereafter to animals also treated with CY, the therapeutic response was not appreciably different from that of mice under therapy with CY only. With regard to the second plasmacytoma (MPC-11 P, a myeloma protein producer), mice treated with CY and given MER prior to or after challenge showed similar responses to animals given chemotherapy only; when MER was injected at the time of challenge and CY thereafter, the chemoimmunotherapy was somewhat inferior to chemotherapy alone.This work was supported by US Public Health Service Contract NO1-CM-12127, and by grants from Mrs. J. H. Hazen, Ruth Estrin Goldberg Memorial for Cancer Research, Leukemia Research Foundation, Inc., Concern Foundation, Inc., and Mr. and Mrs. M. Gordon