We have studied the effects of ARS addition and deletion on the maintenance of a 61-kb ring derivative of chromosome III in a minichromosome maintenance mutant of yeast carrying the mcm2-1 mutation. When this ring chromosome, CIIIR, had either of its two strong origins deleted, the resultant chromosome showed a much greater instability in the mutant as compared to that of the wild-type strain. Integration of more ARSs improved the maintenance of CIIIR in the mutant but not in the wild-type strain. Increase in the size of CIIIR, without any ARS addition, did not improve the stability in either strain. A spontaneous revertant for improved growth at 35 degrees C also co-reverted for minichromosome and CIIIR maintenance. The results suggest that ARS malfunctioning leads to minichromosome and chromosome loss from mutant cells, affecting their growth at higher temperatures.

Adenosine Triphosphatases↗

PubMedDate not supplied

Increased uracil nucleotide metabolism during the induction of cardiac hypertrophy by beta-stimulation in rats.

The dynamics of uracil nucleotides was followed in the rat heart during the induction of cardiac hypertrophy by beta-adrenoreceptor stimulation. Isoproterenol (ISO) 5 mg . kg-1 was administered subcutaneously daily for 8 consecutive days. A significant increase in ventricular dry weight (40%) was observed on the 5th day of beta-stimulation, thereafter no further increase occurred. A single dose of ISO increased uridine triphosphate (UTP) concentration and the whole uracil nucleotide pool (UN). The increase was maximal (80 and 100%) 12 hours after ISO administration. The 32phosphate incorporation into the alpha-phosphate group of UN was increased by about a factor of 2 for the same period of time. Slight decrease in pool sizes (UTP and UN) and labelling occurred from 12 to 24 h after beta-stimulation. Similar changes also occurred on the 8th day of ISO administration, however modifications in concentrations and labeling were attenuated. The results show that modifications in the synthesis of UN should also be taken into account when studying the early events leading to cardiac hypertrophy.

Adenosine Triphosphate↗

PubMedDate not supplied

Serum lipid profile and its relationship with host immunity in carcinomas of the breast and uterine cervix.

Carcinomas of the uterine cervix and breast, which have a different etiopathogenesis, are the most common malignancies among Indian women. Between these two cancers a comparative study was undertaken in which serum lipids were assessed along with host immunity. Thirty randomly selected cases each of breast and cervical carcinoma, and 20 matched healthy control women were studied by means of standard procedures. Significantly higher (P < 0.001) mean levels of triglycerides (x = 192.1 mg/dl, SD +/- 113.5) and total cholesterol (x = 212.9 mg/dl, SD +/- 49.78) were observed in breast cancer as compared to controls or cervical cancer patients. Patients with cervical cancer had low mean values of all lipid fractions. Women with the above malignancies also showed a significantly decreased CD3+ and CD4+ population (P < 0.001), while there was a significant increase in CD8+ cells (P < 0.005) compared to normal controls. Interestingly, a significant relationship (P < 0.05) was observed between CD8+ cells and LDL-cholesterol among the cancer patients (r = 0.3652 and r = 0.4298 for carcinomas of breast and cervix, respectively.

Adult↗