Supression by copulation of the inhibitory effect of p-chlorophenylalanine on rat ovulation (author's transl)]

The effect of copulating on reflex ovulation was studied in rat. The effect of PCPA (300 mg/kg, i.p.) on ovulation and reproduction was compared by evaluating number of oocytes in tubes, histologic features of ovaries, vaginal cycle, insemination, fertilization and number of embryos per rat. PCPA, administered on 9th and 16th h of the estrus phase, totally inhibits ovulation, stimulates reproductive behaviour and prolongs the estrogenic phase. When the animals are kept in copulatory conditions for 16 or 46 hours, the inhibition induced in ovulation disappears to the extent that 60% of the rats become pregnant though the number of embryos is under that of the control group. The farther the treatment with PCPA within the same cycle in the ovulatory period, the greater the inhibitory effect on ovulation is and the lesser the neutralizing effect produced by reflexes related to copulation. Administration of PCPA at the 16 hour of the diestrus causes a greater increase in the average number of embryos-as compared to administration at the 9 hour. In periods longer than 48 hours before ovulation, the inhibition brought about by PCPA is not suppressed by copulatory conditions kept for 16 or 24 hours and is only neutralized if they are kept during a complete cycle. Those treated with PCPA in the diestrus phase and maintained in copulatory conditions for 46 hours, present a higher average of embryos than those maintained in similar conditions for 16 hours.     

Effect of p-chlorophenylalanine on the reproduction of the rat (author's transl)]

The effect of p-chlorophenylalanie (p-CPA) --300 mg/kg-- on reproduction has been studied in the female rat. Groups of animals were injected with a dose of 300 mg/kg of p-CPA 48 hours before proper copulation conditions at different moments along the ovarian cycle. Presence of spermatozoa in the vaginal frotis was negative in treated rats; in the control groups however, positivity was found in variable proportions according to the phase of the ovarian cycle: 30 ad 90% in diestrus and proestrus respectively. Treated animals showed continuous diestrus phases and diffuse luteinitation of the ovary. The results may indicate that a decrease of cerebral 5-HT, caused by p-CPA, lessens the reproductive behaviour of the female rat through mechanisms depending probably on the liberation of gonadrotrophins.     

Modification of the ovarian cycle, ovulation and reproduction in rat by administration of p-chlorophenylalanine in the pre and post ovulation period (author's transl)]

The effect of p-Chlorophenylalanine (PCPA) administered in pre and post-ovulation phases on ovulation reproduction and ovarian cycle was studied in rats. Vaginal smears, number of ovules, mature follicles and ovaric histologic features were evaluated. PCPA administered in the periods after follicular rupture prolongs the diestrus phase from 2 to 10 consecutive days and totally inhibits the reproductive conduct. When administered in the periods just prior to follicular rupture, PCPA prolongs the estrus phase from 2 to 4 consecutive days and does not totally inhibit reproduction. A progressive increase in reproduction took place as treatment time approached ovulation, to such an extent that the number of inseminated and fertilized rats when treated at the ninth hour of the proestrus phase, was superior to the control group. PCPA administered in periods after and before follicular rupture totally inhibits ovulation in all cases. Ovaries present many mature follicles, as many as in the controls sacrificed at the 18 hour of the proestrus, just before ovulation.     

Effect of p-chlorophenylalanine on rat reproduction under different conditions of lighting (author's transl)]

Reproduction in female rats kept on artificial cycles of light/darkness, continuous lighting and continuous darkness, has been studied. Three weekly doses of p-chlorophenylalanine (p-CPA), 100 mg/kg, were given to half of the rats in each group during the two preconditioning months before copulation. An evaluation has been made of the insemination, fecundation, number of embryos, ovarian cycle and level of 5-HT in the hypothalamus. The administration of p-CPA had an inhibitory effect on the reproductive behavior, especially pronounced in rats kept under continuous lighting and under continuous darkness. The difference in 5-TH levels were greater among the groups kept on cycles of light/darkness without treatment and with p-CPA (0.05 greater than P greater than 0.01). The importance of 5-HT in the mechanisms of reproductive behavior is emphasized.     

Effect of alloxan in pancreatectomized rats (author's transl)]

Sensitivty to alloxan of pancreatectomized rats is studied injecting on the seventh day after surgical resection with different dose of monohydrated alloxan. Totally pancreatectomized rats develop a strong diabetes just the same as the control group, but the former present higher glycemias and longer survival.     

Multiple osteosarcoma in spontaneously hypertensive rats (author's transl)]

For period from 1971 to 1975, 18 cases of osteosarcoma were experienced among 9132 spontaneously hypertensive rats. The onset was at 72 to 145 days of age and death occurred before 423 days of age. The tumors were multiple being distributed in the skull (11 of 14 cases), caudal vertebrae (8 of 14 cases), and fore- and hind-limb. All the tumors were mainly composed of sarcomatous tissue with some osteoid and cartilage. Metastasis was never observed. Serum A1-P levels of tumor bearing animals were 2 times higher than those without tumor. Bronchiectasis and abscess formation of submaxillary lymph nodes were noted in most affected animals.     

Effects of the population density on growth of SD-JCL rats (author's transl)]

The effects of the population density on growth and life span of 21 to 26 months in SD-JCL-rats were investigated. The mean life spans of males and females were 23 and 24 months, respectively. The population density had no definite influence on increase in body weight of females, whereas a most accelerated growth of males was seen with 2 rats per cage. The total amounts of food intake of each animal throughout its life were about 15 and 11 kg for males and females, respectively, and those of water intake were about twice the food. No correlation was observed between the population density and the weights of the liver, kidney, heart and femur, though mals reared at 5 animals per cage had lightest adrenals among all the animals.     

Diaplacental passage of Sarcocystis antibodies in man and rats (author's transl)]

Sera of babies up to the age of 3 months were tested for Sarcocystis antibodies using the indirect immunofluorescence test (IIFT). In addition titre of the Sarcocystis antibody level of litters born to serologic Sarcocystis positive mother rats was compared to those of their mothers. The results are as follows: 1. 45 (= 14.6%) out of 308 sera from babies up to the age of 3 months reacted positively in the Sarcocystis antibody test. 2. 28 (= 62.2%) out of the 45 positive sera were from babies up to 2 weeks old, 13 (= 28.9%) were from babies older than 2 weeks but not more than 4 weeks old, and 2 (=4.4%) each were from babies whose ages ranged from 4 to 8, and 8 to 12 weeks respectively. 3. These babies acquired their Sarcocystis antibodies which decreased in the first 3 months of life from their mothers. 4. Litters born to serologic Sarcocystis positive mother rats also demonstrated Sarcocystis antibodies. The titres of these antibodies were at the same level as their mothers' at birth but reduced gradually so that most of these young rats were negative at the age of 3 months. 5. Suckling rats born to Sarcocystis negative mothers but positive fathers remained negative. 6. Serologic positive mother and father rats still demonstrated Sarcocystis antibodies in the sera at a time when their litters have become negative. 7. Sarcocystis antibodies could be passed onto the newborn from their positive mothers in both man and rats. 8. These antibodies were probably passed onto the newborn through the placenta but their passage through the colostrum and the mother's milk cannot be ruled out.     

Bacteroides and appendicitis (author's transl)]

Bacteroides fragilis is frequently recovered from cases of appendicitis with perforation and from infections developing secondary to appendicitis. In order to assess the part played by B. fragilis in the aetiology of appendicitis, quantitative aerobic and anaerobic culture studies of the contents of 49 inflammated appendices were performed. Anaerobic gram-negative non-sporing rods were cultivated from 43 appendices in the range 10(3)-10(9)/g. A total of 1,473 isolates was differentiated by biochemical methods, and 1,374 cultures were found to belong to the saccharolytic species of the genus Bacteroides (B. fragilis, B. thetaiotaomicron, B. vulgatus, B. distasonis etc.). B fragilis was detected in 31 appendices; the species predominated in 18 samples. B theraiotamicron, recovered from 27 samples, was prevalent in 4 appendices. In one sample, B. fragilis and B. thetaiotaomicron outnumbered the other appendicular bacterial. B. vulgatus was cultivated from 12 appendices, but did once constitute the prevalent group. It has been previously shown that B. vulgatus (43% of intestinal isolates) and B. thetaiomicron predominate in the normal narge bowel flora. On the other hand, approximately 80% of pyrogenic Bacteroides strains belong to B. fragilis, B. thetaiotaomicron accounting for 19% and B. vulgatus being virtually absent. From these striking differences in species distribution the conclusion was drawn that B. fragilis possesses the highest virulence for man. Species distribution within the 1,374 appendicular isolates of saccharolytic Bacteroides (percentages of 62, 19 and 4.3 for B. fragilis, B. thetaiotaomicron, and B. vulgatus, respectively) was very similar to that encountered in clinical specimens. From the results obtained it becomes evident that pyrogenic Bacteroides, in particular B. fragilis, plays an important role in nearly 50% of cases of appendicitis.