Antibiotic resistance and plasmid pattern of enterotoxigenic ST-a strains of Escherichia coli isolated in Puebla, México

Antibiotic susceptibilities of 22 strains of Escherichia coli isolated from children from 0 to 3 years old at the University Hospital of Puebla were determined. Almost all strains were resistant to ampicillin, tetracycline, streptomycin, and kanamycin. Gel electrophoresis of DNA from 10 clinical strains of E. coli revealed a heterogeneous plasmid population. Plasmid DNA, ranging in molecular mass from 1.8 to 120 megadaltons, was demonstrated in 10 strains. Moreover, the frequency of antibiotic transfer ranged from 1.6/10(8) to 2/10, and the simultaneous transfer of the gene encoding heat-stable enterotoxin was also determined. Six out of 10 strains tested were able to cotransfer ST-a as demonstrated by the suckling mouse test. It is possible that antibiotic selective pressure may increase the isolation of enterotoxigenic E. coli strains.     

The activity of alkaline phosphatase in the sera of DBA/2NCrj and CBA/BrA mice with calcified tongue lesions

Spontaneously occurring calcified lesions were found in the tongues of DBA/2NCrj and CBA/BrA mice. In the DBA/2NCrj strain, the frequency of the lesion was 80% (males) and 88% (females). The youngest age of a mouse with this lesion was 18 days after birth, and 3-4 lesions were found in the tongue of 6- to 8-week-old mice. In CBA/BrA mice, 20% of females and 48% of males had the lesions. No significant differences were found in the serum calcium concentrations in high and low lesion-developing strains, but the alkaline phosphatase activities in the high-developing DBA/2NCrj, DBA/LiA, and CBA/BrA strains were higher than in strains with no calcified lesions.     

Coprophagy in the germfree mouse

Coprophagy was observed in germfree (GF) ICR mice of both sexes, and the results were compared with those of conventional mice. Frequency of coprophagy per animal per day in GF mice was 5.1 in males and 5.8 in females. In conventional (CV) mice, the frequencies were 6.2 in males and 5.3 in females (data from Zoological Science 2:249-255, 1985), with no significant differences compared with GF mice. Coprophagy in CV mice was frequently observed during 6-8 hr after lighting, whereas such close time relationships tended to weaken in GF animals. In a comparison of levels of constituents per unit weight between feces and diet, fecal crude protein and crude fat exhibited lower values than those in the diet. Levels of fecal crude ash and crude fiber were higher than those in the diet, and nitrogen-free extract was almost equal to that in the diet. No essential difference in these tendencies was found compared with CV mice. Levels of fecal vitamin B1, B2, B12 and folic acid were lower than those in the diet. In CV mice, except for vitamin B1, these vitamins exhibited either almost equal or much higher levels compared with those in the diet (data from Experimental Animals 35: 381-386, 1986). From the fact that coprophagy was observed in GF mice, it is suggested that the behavior is inherent in the mouse.     

Nonsurgical collection of embryos in Shiba goats

A method of nonsurgical embryo collection in the Shiba goat, a native Japanese miniature goat breeding nonseasonally, was developed. The apparatus used for flushing the uterus was made on the model of the two-way catheter for cows. Embryo collection was performed on days 5 to 7 in 37 females superovulated with PMSG and hCG and resulted in successful recovery of 69 embryos in 19 females (51.4%). The average number of embryos collected from each successful female was 3.6. The recovery rate of embryos calculated on the basis of the number of embryos recovered and corpora lutea observed by culdoscopy in 15 successful females was 89.5%. This nonsurgical method seem to be efficient enough for collecting morulae and blastocysts in Shiba goats.     

Study on the optimum number of trials and intensity of unconditioned stimulants and strain difference in the two-way shuttle-box avoidance test using rats

In order to determine the optimun conditions suitable for a number of trials and the intensity of unconditioned stimulant (US) in the two-way shuttle-box avoidance test in Sprague-Dawley strain rats, which are used most frequently in reproduction studies, conditioned avoidance response was observed under various conditions for 30 and 60 trials and the low and high US levels. Investigation was also conducted in Wistar rats under a high US level with 30 and 60 trials. Latency time of the escape response in Sprague-Dawley rats was shortened with increasing trials. Body weight gains of both strains of rats in the high US level with the 60-trial group decreased during the observation period. These findings suggest that the high US level with the 60-trial group is not suitable for the two-way shuttle-box avoidance test. The rate and latency time of the avoidance response were lower in Wistar rats than in Sprague-Dawley rats, although those of the escape response were higher. Significant changes in the following were observed, mainly from first to third sessions: the avoidance rate of all groups in strains of rats, escape rate of 60-trial group in Sprague-Dawley rats, avoidance and escape latency time of the 60-trial groups in both strains of rats and escape latency time of the 30-trial group in Sprague-Dawley strain rats.     

L-641,953 (R-8-fluoro-dibenzo[b, f]thiepin-3-carboxylic acid-5-oxide): a novel thromboxane-prostaglandin endoperoxide antagonist

The effects of L-641,953 (R-8-fluoro-dibenzo[b, f]thiepin-3-carboxylic acid-5-oxide) have been studied on pulmonary and other smooth muscle preparations in vitro and in vivo. When studied in vitro on guinea-pig tracheal chains, L-641,933 produced significant shifts in the dose-response curves to the prostaglandin endoperoxide analogues, U-44069 (pA2 7.06) and U-46619 (pA2 7.14), and prostaglandin (PG) F2 alpha (pA2 6.33) had minimal activity against contractions induced by histamine (pA2 4.38), 5-hydroxytryptamine (pA2 4.63), and acetylcholine (pA2 4.56) and slightly enhanced relaxation induced by PGE2. When tested on the guinea-pig gall bladder strip in vitro, L-641,953 antagonized contractions induced by U-44069 (pA2 7.03) but was less active against those induced by PGF2 alpha (pA2 6.03), PGE1 (pA2 5.62), and histamine (pA2 4.84). When tested in vitro on the guinea-pig pulmonary artery, L-651-953 significantly antagonized contractions induced by U-44069 (pA2 7.04), U-46619 (pA2 7.14), and PGF2 alpha (pA2 7.16) but was less effective against contractions induced by histamine (pA2 4.19). Schild analysis indicated that L-641,953 was fully competitive against contractions of either the guinea-pig tracheal chain induced by U-46619 or the guinea-pig pulmonary artery induced by U-44069 and U-46619. When tested on human platelets in vitro L-641,953 inhibited aggregation induced by U-44069 (IC50 1.3 X 10(-6) M) but not ADP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Renin substrate (angiotensinogen) preparations in the determination of prorenin and renin: evidence for extrarenal plasma prorenin and its renal "convertase"

Standard methods for determining prorenin-renin concentrations in plasma (PRC) and other tissues require the addition of exogenous renin substrate (angiotensinogen) to improve the kinetics of the renin reaction. We studied the effects of substrate prepared from normal human plasma fraction Cohn IV-4, or from nephrectomized (2NX) sheep plasma, on PRC of normal and 2NX human plasmas before and after prorenin activation by acid, cold, and trypsin, and compared the results with plasma renin activities (PRA, no added substrate). Plasmas from 2NX men exhibited negligible basal PRA, indicating that very little, if any, renin had been formed from the extrarenal prorenin they contained, and suggesting the lack of an endogenous prorenin activating mechanism, or "convertase," of probable renal origin. Prorenin was demonstrable by tryptic activation, more than by acid or cold, at up to about 30% of normal. Addition of Cohn IV-4 substrate to 2NX plasma unexpectedly produced (i) a basal PRC value higher than in normal plasma, (ii) total renin values after activation by acid, cold, and trypsin that were much closer to normal values than reflected by PRA methodology, without a commensurate increase (if anything a decrease) in prorenin as a percentage of total renin estimated by all activation methods, and (iii) substantial equalization of activation effects such that trypsin was no longer more effective than acid and cold (and this was also noted with normal plasma). The skewing effect of adding Cohn IV-4 substrate on the PRC of 2NX plasma was much greater than in normal plasma, even though 2NX plasma already had an above normal level of endogenous substrate and should have been influenced less. Enhancement of PRC was very pronounced even when Cohn IV-4 was added to make up only 9% of total (endogenous + exogenous) substrate in the incubation system, suggesting that it was not the added substrate but a renin-generating contaminant that inflated the PRC. Such inflation could be blocked by adding protease inhibitors, suggesting that the responsible protease(s) acted as a prorenin "convertase" that generated new renin from renal and (or) extrarenal prorenin contributed by the added substrate, as well as by the plasma being assayed. One component of convertase could be kallikrein, which was identified by chromogenic assay, the importance of which relative to total convertase activity is unknown.(ABSTRACT TRUNCATED AT 400 WORDS)     

Hypersomatostatinemia in chronic renal failure

Plasma concentrations of somatostatin-like immunoreactivity (SLI) were determined in uremic patients on maintenance hemodialysis. Plasma SLI levels were significantly (p less than 0.001) elevated in 26 diabetic uremic patients (67.1 +/- 6.8 pg/ml, mean +/- SE) and in 24 non-diabetic uremic patients (43.5 +/- 7.2 pg/ml), when compared with 60 healthy subjects (5.0 +/- 0.7 pg/ml). Paired pooled plasma from uremic patients before and after hemodialysis was subjected to a reverse-phase octadecasilyl-silica (C-18) cartridge and then the extract was gel filtered on a Sephadex G-25 column (1.6 X 90 cm). Both elution profiles showed two peaks of SLI which coeluted with synthetic somatostatin (SS)-28 and SS-14 markers, respectively. The SS-28-like immunoreactivity (LI) peak, which was estimated by using SS-14 as a reference standard, was 3-fold larger than that for SS-14 LI. On the basis of immunoequivalency of the two components in the present assay, SS-28 LI constitutes approximately 75% of circulating somatostatin. In conclusion, plasma SLI is substantially high in uremic patients of both diabetic and non-diabetic etiology and the SS-28 is a predominant form of circulating SLI in these patients, probably, in part, for a lower clearance of this molecule.     

A case of von Recklinghausen's disease associated with pheochromocytoma and papillary carcinoma of the thyroid gland

A 58-year-old woman was admitted to our hospital complaining of headache, dizziness and intermittent elevation of blood pressure. Multiple café-au-lait spots and neurofibromas had appeared on the back and the limbs since the age of 30 years. At the age of 54 years she underwent total thyroidectomy because of papillary carcinoma of the thyroid gland. On admission, the levels of plasma norepinephrine and epinephrine, urinary norepinephrine and normetanephrine were all within the normal range. However, urinary excretion of metanephrine was markedly increased to 1.49 +/- 0.45 (Mean +/- SD) mg/day and that of epinephrine was also slightly increased. The computed tomographic scans of the abdomen and the scintigraphy with 131I-metaiodobenzylguanidine revealed a tumor mass in the region of the right adrenal gland. The tumor was histologically confirmed to be pheochromocytoma at the operation. In her family history, her mother and one of her two sisters had von Recklinghausen's disease and another sister suffered from follicular carcinoma of the thyroid gland. As far as we know, this paper is the first report of a patient with von Recklinghausen's disease associated with both pheochromocytoma and non-medullary carcinoma of the thyroid gland, and her family.