Genetic resistance to mammary tumorigenesis in a mouse strain with high murine mammary tumor virus expression

Although II-TES mice release large amounts of murine mammary tumor virus (MMTV) in milk, they are resistant to mammary tumorigenesis. High mammary tumor incidence was observed in (BALB/ca X II-TES)F1 and (C57BL/6N X II-TES)F1, whereas no mammary tumors developed in BALB/ca X OZ-F)F1. Mammary tumors developed in 68% of (OZ-F X (OZ-F X II-TES)F1 and 45% of (II-TES X (OZ-F X II-TES)F1). These results suggest that the II-TES mouse carries a recessive gene for mammary tumor resistance which does not inhibit MMTV release, and two independent dominant mammary tumor promoting genes which are inhibited by the resistant gene.

Analysis of surface deposits on intrauterine contraceptive devices

Surface deposits on stainless steel contraceptive devices removed from the uterus after varying periods of insertion were examined and analyzed by means of scanning electron microscopy (SEM), X-ray energy dispersive analysis (XEDA), Augar electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and atomic absorption spectrophotometry for microquantitative analysis. The data obtained were compared with the data for copper-bearing IUDs (TCu200) obtained by the same method. The wire coils of stainless steel IUDs which had been in situ for 5 years showed no obvious changes, but copper wire coils showed varying degrees of erosion after the same period of time. Analysis clearly showed that the wire coils of both types of IUD were encrusted with deposits. Deposition began earlier on copper-bearing IUDs than on stainless steel IUDs (27 days and 3 months after insertion, respectively). This process began earlier than has previously been reported in the literature. The amount of deposit increased with duration of insertion, but there were large individual variations. The microanalysis showed that the principal component of the deposit on both types of IUD was calcium, which was present in the crystal form of calcium carbonate. The substances attaching to the crystals were similar to the nitrogenous organic compounds. We suggest that the mechanism regulating the deposited formation may be similar to that of calculus. The influence of these deposits on complications relating to IUD insertion, such as uterine bleeding and accidental pregnancy, is briefly discussed in this article. The subject should be studied in greater detail.

Oxygen quenching of sensitized terbium luminescence in complexes of terbium with small organic ligands and proteins

Oxygen does not quench the luminescence of either free Tb or of Tb bound to dipicolinate. However, sensitized Tb luminescence in complexes of that ion with elastase, thermolysin, and alpha-amylase is quenched by oxygen at rates that far exceed that with which the intrinsic fluorescence of the proteins is quenched. We infer that this more rapid quenching of Tb luminescence indicates a major role for energy transfer from tryptophan moieties in a triplet excited state.

Hepatic damage in experimental and clinical paragonimiasis

The hepatic damage induced by Paragonimus skrjabini, and the migration route of this species and that of P. westermani, were investigated in a series of animal experiments and in 34 clinical and four autopsy cases of paragonimiasis. The major symptoms and signs of an unique case reported from Sichuan Province included hepatic tenderness, disturbance of hepatic functions, remittent fever, and cough with bloody sputum. Laparotomy revealed marked adhesions surrounding the liver, spleen and duodenum. Diagnosis was made by finding P. skrjabini in a bulla on the abdominal wall about 5 months after the onset of illness. After specific treatment with bithional, body temperature and liver functions returned to normal. Twenty-three of 33 cases independently studied from Fujian Province also showed similar hepatic function disturbance. Autopsy cases showed hepatic chronic eosinophilic abscesses with Charcot-Leyden crystals. Experimentally, P. skrjabini infection caused hepatic damage in all laboratory animals used. The main pathologic changes were initially acute eosinophilic abscesses in the liver, worms being found sometimes in the necrotic cavities of the abscesses; hepatomagaly also occurred. Some cysts containing mature worms were found in the liver of dogs 3-9 months after infection. Numerous eggs were deposited in the cyst walls. The migration route of P. skrjabini was studied in young dogs. Worms appeared in the liver initially on day 3 and reached their highest level on day 14. P. westermani also migrated into liver, but their numbers were less than those of P. skrjabini.

"Medical oophorectomy" using a long-acting GNRH agonist--a possible new approach to the treatment of endometriosis

Five women with endometriosis were given a daily dose of a potent long-acting GnRH agonist, D-Trp6-Pro9-Net-LHRH (GnRH-A) for 28 days in an attempt to suppress ovarian estrogen secretion. The mean level of estradiol (E2) during sampling over 24 hours decreased (P less than 0.01) from 62 +/- 11 to 10 +/- 1 pg/ml at the end of treatment. Mean concentrations of androstenedione, testosterone, estrone and E2 on day 28 of therapy were similar to those measured in oophorectomized women. The level of FSH was decreased (P less than 0.001) during GnRH-a, whereas that of LH was significantly (P less than 0.001) increased, suggesting differing intracellular control mechanisms for release of the two gonadotropins. Desensitization of the pituitary was demonstrated at the end of treatment by a complete lack of acute response of FSH or LH to the daily dose of GnRH-a. "Medical oophorectomy" provides a new approach to the treatment of endometriosis.

Cloning of a yeast gene coding for arginine-specific carbamoyl-phosphate synthetase

Several recombinant plasmids containing cpaII, the gene that encodes the large subunit of yeast arginine-specific carbamoyl-phosphate synthetase [carbamoyl-phosphate synthetase (glutamine-hydrolyzing), carbon-dioxide: L-glutamine amido-ligase (ADP-forming, carbamate-phosphorylating), EC 6.3.3.5], have been isolated. The plasmids were selected by transformation of a yeast strain with a mutation in the structural gene of the large subunit of carbamoyl-phosphate synthetase. By using a recombinant pool with inserts of yeast nuclear DNA of 5-20 kilobase pairs, we obtained 13 transformants. Of five transformants studied, three have been found to have stable plasmid inserts. These plasmids could be amplified in Escherichia coli and transferred back into the yeast carbamoyl-phosphate synthetase-deficient strains with concomitant complementation of the nuclear mutation. Plasmids pJL2/T1 and pJL2/T5 contain identical nuclear DNA inserts of 5.9 kilobase pairs. Although the insert of plasmid pJL2/T3 is also 5.9 kilobase pairs long, the sequence overlap with pJL2/T1 and pJL2/T5 is only 4.5 kilobase pairs long. The T3 insert has an orientation in the vector opposite to that of the T1 and T5 inserts. The recombinant plasmids with the yeast cpaII gene fail to cross-hybridize with a cloned fragment of E. coli DNA containing the carA and carB genes for the bacterial carbamoyl-phosphate synthetase.

Diet and vitamin nutrition of the high esophageal cancer risk population in Linxian, China

In order to examine the nutritional status of the population of Linxian (in Henan, China) known to be at high risk for esophageal cancer (EC), we analyzed blood samples and conducted 3-day dietary surveys on 3 groups of normal adults, age 40-50, from Henan province. Two groups were from Linxian, where the EC mortality rate is about 138/100,000 (Group C, consisting of volunteers with a family history of EC, and Group NC, consisting of those who did not have a family history of EC). The third group, Group F, was from Fanxian, where the EC mortality rate is about 24/100,000. The average plasma retinol level was found to be about 0.27 micrograms/ml in all 3 groups; about 13%-20% of the individuals had a level less than 0.2 micrograms/ml. The average plasma carotene level of all 3 groups appeared to be adequate, ranging from 0.5-1.0 micrograms/ml. About 23% of the subjects in both Groups C and NC had low (less than 2 micrograms/ml) plasma ascorbate levels; in Group F, 16% had low ascorbate levels. Less than 12% of the individuals in each of the 3 groups had erythrocyte glutathione reductase activation coefficients less than 1.2, indicating a widely occurring riboflavin deficiency. Consumption of alcoholic beverages was not found to be a contributing factor to EC. The results of the present study reveal a deficiency of vitamins in the study populations, but do not indicate that the average nutritional status of the volunteers in Group C was worse than that of Groups NC and F with regard to vitamin A, ascorbate, and riboflavin.