Role of cholecystokinin (CCK)-A receptor for pancreatic growth after weaning: a study in a new rat model without gene expression of the CCK-A receptor

This work extends a recent observation that Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which have been established as an animal model of non-insulin-dependent diabetes mellitus, show no expression of the cholecystokinin (CCK)-A receptor gene in the pancreas. The CCK-A receptor is known to be involved in regulating pancreatic exocrine function and growth. We examined the growth of the pancreas in terms of wet weight, enzyme compositions, and protein and DNA contents at 5-6 and 24-25 weeks of age in OLETF rats and control (Long-Evans Tokushima; LETO) rats. The pancreatic wet weight increased significantly with age in both OLETF and LETO rats but was significantly lower in OLETF rats than in LETO rats. The total DNA contents in the whole pancreas (cell numbers) were comparable for both strains and increased significantly with age. However, the ratio of protein content to DNA content (the cell size) significantly increased with age in LETO rats, with no increase in OLETF rats. The changes in chymotrypsin, amylase, and insulin with respect to age were in the same direction in both strains: a decrease or no change in total and/or cellular contents of chymotrypsin and insulin and increases in amylase. These results suggest that the CCK-A receptor plays some role in the increase in cell size associated with normal growth of the pancreas from 5 to 25 weeks of age (after weaning).

Effects of pancreatic duct ligation and aging on acute taurocholate-induced pancreatitis. Experiments in the perfused pancreas in rats

CONCLUSION

When taurocholate was injected into the common bile duct, high ductal pressure due to ligation of the pancreatic duct did not produce more damage in the pancreas of both old rats and young adult rats, and levels of pancreatic enzymes in portal venous effluent were lower in old rats than in younger rats.

BACKGROUND

The effects of ligation of the pancreatic duct and aging on acute pancreatitis caused by taurocholate are still unclear.

METHODS

Young adult and old male Wistar rats were used. Six hours after ligation of the common bile duct in both the duodenum and liver hilus, rats were killed and the pancreata were perfused. Taurocholate or normal saline was injected retrogradely into the common bile duct. The levels of amylase and lipase in the portal venous effluent were determined as markers of damage to the pancreas. The pancreas was also histologically examined after the perfusion experiments using an Image Analysis System.

RESULTS

(1) A nonsignificant elevation of pancreatic enzymes was found in portal venous effluent by the retrograde injection of saline into the common bile duct. Injection of taurocholate caused a marked elevation of enzymes in the effluent for the first 30 min after injection, which then gradually decreased. (2) Basal levels of pancreatic enzymes were significantly higher in the ligation group than in the nonligation group. Injection of saline into the common bile duct had no apparent effect on enzymes in the effluent. In contrast, taurocholate injection into the common bile duct produced a marked increase in enzymes in the portal venous effluent. However, no significant difference was found between the ligation group and the nonligation group. (3) Similar findings were obtained when old rats were used. (4) Although basal levels of enzymes were almost the same in nonligated old and young adults rats, taurocholate injection into the pancreatic duct in old rats resulted in a significant depression of enzymes compared to that in young adult rats. In the ligation group, pancreatic enzymes in the portal venous effluent following taurocholate injection tended to be lower in old rats than in young adult rats. The results were histologically supported in that various degrees of fibrosis were found in the pancreata of old rats.

Pancreatic endocrine dysfunction in rats not expressing the cholecystokinin-A receptor

Cholecystokinin (CCK) has been suggested to modulate insulin output. We have shown that Otsuka Long-Evans Tokushima Fatty (OLETF) rats show little or no expression of the CCK-A receptor gene in the pancreas. We examined whether the CCK-A and CCK-B receptor genes are expressed in the islets and the role of CCK-A receptor in insulin secretion. Gene expressions of CCK receptors were determined by the reverse-transcriptase polymerase chain reaction (RT-PCR) followed by Southern blot hybridization and Northern transfer analysis using LETO rats as controls. Pancreatic endocrine function was examined in perfusion (exogenous CCK stimulation) and meal ingestion (endogenous CCK stimulation) studies. CCK-A receptor mRNA was detected in the islets of LETO rats but not OLETF rats. Expression of the CCK-B receptor gene was detected in both strains by RT-PCR. Insulin secretion was impaired in OLETF rats, but the insulin contents of OLETF and LETO rats were not different. No abnormalities were detected histologically in either strain. These results suggest that the occurrence of pancreatic endocrine dysfunction in OLETF rats may be due to a defect in expression of the CCK-A receptor gene, not to insulin deficiency.

Age-related changes in alpha-adrenoceptor-mediated blood pressure in the rat: relationship between the potency for phenylephrine and the maximum number of binding sites

To study the effects of aging on the blood pressure potency of phenylephrine, 6-, 10- and 40-week-old rats were used. In anesthetized rats, the potency (pD2 value) of phenylephrine on the blood pressure tended to increase with age from 6 to 10 weeks, but significantly decreased thereafter with age from 10 to 40 weeks. Similarly, in pithed rats, the potency of phenylephrine significantly increased, but decreased thereafter. In isolated rat thoracic aorta, the pD2 value of phenylephrine from the contractile responses significantly increased with age from 6 to 10 weeks, but decreased thereafter from 10 to 40 weeks. The change in the potency of phenylephrine on the blood pressure was proportional to the pD2 value of phenylephrine estimated in aortic preparations. The specific binding of [3H]prazosin to single smooth muscle cells of thoracic aorta from different aged rats was saturable. The maximum number of binding sites (Bmax) significantly increased with age from 6 to 10 weeks, but decreased thereafter from 10 to 40 weeks. However, the dissociation constant of [3H]prazosin (Kd) did not alter with age. The changes in the potencies (pD2 values) of phenylephrine on the pressure responses and on the contractile responses were proportional to the logarithm of the maximum number of binding sites. The present study suggests that age-related changes in blood pressure are due to changes in the maximum number of binding sites (receptor density) of alpha 1-adrenoceptors.

Somatostatin inhibits pancreatic exocrine secretion centrally via sympathetic nerves in conscious rats

Somatostatin is known to be a potent inhibitor of pancreatic exocrine secretion, but the mechanism of its effect is not fully understood. The mechanism of the inhibition by centrally administered somatostatin was examined in conscious rats. Rats were prepared with cannulae draining bile and pancreatic juice separately, and with a duodenal cannula, an extrajugular vein cannula and a cerebroventricular cannula. Somatostatin was injected into the left lateral ventricle, and the inhibitory mechanism was examined using vagotomized rats and various drugs that affect sympathetic neurons. Intracerebroventricular administration of somatostatin significantly inhibited pancreatic exocrine secretion stimulated by bile-pancreatic juice diversion. The inhibitory effect was not abolished by vagotomy, pretreatment with propranolol, but was abolished by pretreatment with hexamethonium or phentolamine. The plasma level of somatostatin after its intracerebroventricular administration increased 3-fold, but its intravenous infusion at a rate giving a similar plasma somatostatin level to that produced by its intracerebroventricular injection, had no significant effect on pancreatic secretion. These results suggest that somatostatin inhibits pancreatic exocrine secretion centrally via sympathetic efferent nerves and that alpha-adrenergic receptors have an important role in its inhibitory action.

Age-related alteration of alpha(1)-adrenoceptor mechanisms and Ca2+ inhibitory effects of isradipine

The effects of age on alpha1-adrenoceptor and Ca2+ channel-mediated contractile mechanisms in the thoracic aorta, isolated from rats of 3, 6, 10, 18 and 40 weeks old, were studied. The potency (pD(2) value) of norepinephrine increased with age from 3 to 10 weeks, but decreased thereafter from 10 to 40 weeks. The change in pD(2) value of norepinephrine was proportional to the logarithm of the maximum number of binding sites (B(max)), obtained in the [(3)H]prazosin binding study. The inhibitory effect of a potent Ca(2)+ channel blocker, israpidine, on the norepinephrine-induced contraction decreased with age from 3 to 10 weeks, but increased in rats aged 10 to 40 weeks. An inverse relationship between the change in isradipine inhibition, the maximum reduction of isradipine on norepinephrine-induced contraction and the logarithm of B(max) was found. The inhibitory effect of a nonselective Ca2+ channel blocker, SKF96365, on the norepinephrine-induced contraction did not change with age. The amplitude of the Ca2+-induced sustained contraction, after pretreatment with isradipine (10(-7) M) in the presence of norepinephrine (10(-6) M), increased with age from 3 to 10 weeks, but decreased thereafter in rats aged 10 to 40 weeks. There was no significant difference in the slope of the regression lines between the cytosolic Ca(2)+ level ([Ca2+]i) and the tension in the presence of norepinephrine at different ages. These results suggest that the changes in alpha(1)-adrenoceptor mechanisms and the reduction by isradipine with age are due to changes in the alpha1-adrenoceptor density and the population of Ca2+ channels, but not to changes in the affinity of drugs to the alpha1-adrenoceptor or Ca2+ sensitivity of contractile elements of aortic smooth muscles.

Gene expressions of cholecystokinin (CCK) and CCK receptors, and its satiety effect in young and old male rats

Cholecystokinin (CCK), one of the first discovered gastrointestinal hormones, which stimulates pancreatic enzyme secretion and induces gallbladder contraction, is one of the most abundant neurotransmitter peptides in the brain and is implicated in satiety via CCK-A receptors. We compared the suppressive effect of central administration of CCK on food intake in young and old rats. The suppressive effect on food intake was enhanced in old rats. To examine the mechanism of this enhanced suppression, we measured the mRNA levels of CCK, CCK-A and CCK-B receptors in the cerebral cortex and the hypothalamus of young and old male rats. The mRNA level of CCK-A receptors in the hypothalamus decreased with age, whereas the mRNA levels of CCK-B receptors in the hypothalamus and cerebral cortex did not. The mRNA level of CCK in the cerebral cortex decreased significantly in old rats, although the decrease in the hypothalamus was not significant. Therefore, the enhanced sensitivity to CCK of old rats could not be explained by changes in gene expressions of CCK and CCK receptors. Moreover, the effects of aging on the gene expressions of CCK-A and CCK-B receptors were different.

Partial sequence of ribulose-1,5-bisphosphate carboxylase/oxygenase and the phylogeny of Prochloron and Prochlorococcus (Prochlorales)

The prochlorophytes, oxygenic photosynthetic prokaryotes having no phycobiliprotein but possessing chlorophylls a and b, have been proposed to have a common ancestry with green chloroplasts, yet this is still controversal. We report here that partial sequence comparisons of the large subunit of ribulose-1,5'-bisphosphate carboxylase/oxygenase, including sequence data from two prochlorophytes, Prochlorococcus and Prochloron, indicate that Prochlorococcus is more closely related to a photosynthetic bacterium, Chromatium vinosum (gamma-purple bacteria), than to cyanobacteria, while Prochloron is closely related to the prochlorophyte Prochlorothrix and to cyanobacteria. The molecular phylogenetic tree indicates that a common ancestor of Prochlorococcus and gamma-purple bacteria branched off from the land plant lineage earlier than Prochloron, Prochlorothrix, and cyanobacteria.

Biochemical characterization of a Ca(2+)-dependent lectin from the hemolymph of a photosymbiotic marine bivalve, Tridacna derasa (Röding)

A Ca(2+)-dependent lectin was purified from the hemolymph of a photosymbiotic bivalve, Tridacna derasa. An electrophoretically homogeneous form was obtained by using affinity chromatography with Sepharose 4B. More than 80% of the hemolymph protein was accounted for by this lectin. The apparent molecular mass of the lectin, in its native form exhibiting hemagglutinating activity, was estimated by gel filtration analysis to be approximately 480 kDa. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, in the absence of reductants, it migrated as a single band corresponding to a very large size, while in the presence of 2-mercaptoethanol, it migrated as two distinct bands of 23 and 46 kDa. These results indicate that the subunits were linked by disulfide bridges to form the native protein. After reducing pyridylethylation, each of the 23- and 46-kDa polypeptides was isolated by gel filtration in a mobile phase containing guanidine-HCl. The two polypeptides had the same amino-terminal sequence and a similar amino-acid composition, and in the presence of 2-mercaptoethanol gave a single band on isoelectric focusing at a pH of 6.0. The results suggested that the 46-kDa peptide is a homodimer of 23-kDa subunits held together by a covalent bond other than a disulfide linkage. This lectin required calcium ions for its activity. By ultraviolet spectrophotometry the association constant for the calcium ion was determined to be 0.88 mM. The hemagglutinating activity decreased dramatically below pH 6.5, but re-increased to the original level when the solution was neutralized. Such a pH-dependent alteration of the ligand-binding activity was similar to that found in vertebrate asialoglycoprotein receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Decline in glucose metabolism in the brain in neuronal ceroid lipofuscinosis (NCL) in English setter--evidence by positron emission tomography (PET)

Positron emission tomography scans were performed on brains of homozygous and heterozygous English setters with neuronal ceroid-lipofuscinosis (NCL) from 13 months of age to 24-25 months of age for homozygous dogs and to 38 months for heterozygous dogs, respectively. After iv injection of 18F-fluorodeoxyglucose (FDG), 7 coronal brain scans as well as sequential arterial blood samplings were performed for 45 min under pentobarbital anesthesia. From these data, three different functional images (DAR (standardized uptake value), FDG uptake (fractional uptake) and glucose uptake) were reconstructed and quantitatively analysed. In the age range from 13 to 15 months, glucose images were comparable for both homozygous and heterozygous dogs, so that no differentiation was possible between healthy and diseased dogs on the basis of PET findings. Between 18 and 24 months of age, a drastic decline in glucose metabolism was observed in homozygous dogs, while the decline in glucose utilization was very mild in this period for heterozygous dogs. Furthermore, in PET scans, cerebral atrophy and ventricular enlargement were clearly shown in homozygous dogs. Consequently at the age from 20 to 24 months, a clear differential diagnosis between healthy (heterozygous) and diseased (homozygous) dogs became possible even if the clinical symptoms were still not clear in the latter. We conclude that the biochemical alterations in the brain in canine NCL occurs and progresses very rapidly in the last quarter of their lives.

Lack of satiety effect of cholecystokinin (CCK) in a new rat model not expressing the CCK-A receptor gene

This work expands recent observations that Otsuka Long-Evans Tokushima Fatty (OLETF) rats show little or no pancreatic expression of the cholecystokinin (CCK)-A receptor gene. We examined whether the CCK-A and -B receptor genes were expressed in the brain (hypothalamus) of OLETF rats in comparison with control (Long-Evans Tokushima Otsuka = LETO) rats. CCK-A receptor mRNA was detected in the hypothalamus of LETO rats but not OLETF rats. The CCK-B receptor gene was expressed in the hypothalamus in both strains. Cerebroventricular administration of CCK-8 sulfate inhibited daily food intake in LETO rats, but not in OLETF rats. These results show that in OLETF rats the absence of CCK-A receptor gene expression in the hypothalamus results in hyperphagia because of lack of satiety.

(-)Deprenyl increases the life span as well as activities of superoxide dismutase and catalase but not of glutathione peroxidase in selective brain regions in Fischer rats

(-)Deprenyl, a MAO-B inhibitor that is also known to be effective for symptoms of Parkinson's disease, when injected subcutaneously (sc) in male Fischer-344 rats at a dose of 0.5 mg/kg per day (3 times a week) from 18 months of age, significantly increased the remaining life expectancy. The average life span after 24 months was 34% greater in treated rats than in saline-treated control animals. Furthermore, a short-term (3 wk) continuous sc infusion of deprenyl significantly increased activities of superoxide dismutase and catalase but not of glutathione peroxidase in selective brain regions such as s. nigra, striatum, and cerebral cortex, but not in hippocampus or cerebellum, or the liver. The optimal dose for increasing these activities, however, differed greatly depending on the sex and age of animals, with a 10-fold lower value for young female than male rats. Interestingly, aging caused an increase and a decrease in the optimal dose in female and male rats, respectively. In addition, treatment for a longer term tended to reduce the optimal dosage in the same animal group. The results clearly demonstrate that deprenyl increases antioxidant enzyme activities in selective brain regions. If this effect of deprenyl is causally related to its life-prolonging effect, the dosage to be used for any life span study would be a critical factor, with the dosage differing widely depending on sex, age of animal, and mode and duration of drug administration.

The effect of a long term (6 months) treatment with (-)deprenyl on antioxidant enzyme activities in selective brain regions in old female Fischer 344 rats

The effect of long term treatment with (-)deprenyl (s.c. injection three times a week for 6 months) on superoxide dismutase (SOD) and catalase (CAT) in selective brain regions was examined in old (22 months) female Fischer 344 rats. The three doses of deprenyl used (0.1, 0.25 and 0.5 mg/kg/day) increased the activities of both enzymes in substantia nigra, striatum and cerebral cortices essentially in a dose dependent manner. However, for CAT activities in cerebral cortices, the smallest dose of 0.1 mg/kg/day was most effective, while the highest dose (0.5 mg/kg/day) had no effect. In contrast to these brain regions, there were no significant differences in enzyme activities between control and deprenyl-treated groups in the hippocampus and cerebellum. If the effect of deprenyl on the life span of female F-344 rats is causally related to its effect on antioxidant enzyme activities in selective brain regions as shown in this study, then a dose of 0.25 or 0.5 mg/kg/day appears to be most appropriate. Since this dose is much lower than the dose suggested by our previous short term (3 week) experiments, an even longer term experiment is necessary to determine the optimal dose of deprenyl to increase free radical scavenging and thus possibly extend lifespan.

Tauro alpha-muricholate is as effective as tauro beta-muricholate and tauroursodeoxycholate in preventing taurochenodeoxycholate-induced liver damage in the rat

Male Wistar rats were infused intravenously with taurochenodeoxycholate (0.4 mumol/min/100 gm) alone (group A) or with one of the three bile salts (tauroursodeoxycholate [group B], tauro beta-muricholate [group C] or tauro alpha-muricholate [group D]) at a rate of 0.2 mumol/min/100/gm for 1 hr. One-hour bile flow and bile salt excretion rates were significantly lower in group A than in the other three coinfused (B, C, D) groups. Biliary 1-hr outputs of lactate dehydrogenase and albumin in the bile, on the other hand, were significantly higher in group A than in the other groups. Plasma concentrations of lactate dehydrogenase at the time of killing (1 hr) were two to three times higher in group A than in the other groups. Although tauro alpha-muricholate does not possess a 7 beta-hydroxy group, the 6 beta-hydroxy group that tauro alpha-muricholate possesses thus appears to be as effective as a 7 beta-hydroxy group in reducing the liver damage caused by toxic bile salts such as taurochenodeoxycholate. The so-called hepatoprotective effects of tauroursodeoxycholate and tauro beta-muricholate found in previous studies may require explanation(s) other than the presence of a 7 beta-hydroxy group in their molecular structures.

Ursodeoxycholic acid reduces the systemic toxicity of 1,2-dichloro,4-nitrobenzene by stimulating hepatic glutathione S-transferase in mice

Male C57BL/6 mice were fed with normal diet (ND) or diets containing 0.3 or 0.5% ursodeoxycholic acid (UDCA) for 3 weeks. Glutathione S-transferase (GST) activities in the liver cytosolic fraction of these animals toward 1,2-dichloro,4-nitrobenzene (DCNB) as well as to 1-chloro,2,4-dinitrobenzene (CDNB) were significantly increased in a dose dependent manner in UDCA-treated groups compared with the control (ND-fed) animal group (one-way ANOVA). Reduced glutathione (GSH) levels tended to slightly decrease with UDCA diets but the difference did not attain a statistical significance (P > 0.05, one-way ANOVA). Twenty four hr survival rates after an oral challenge of 3.5 mg/kg of DCNB were significantly higher (P < 0.05, Chi-square test) in the two UDCA fed groups (10/10 for 0.5% group, 8/11 for 0.3% group) compared with the control group (3/11). Thus, UDCA appears to reduce the systemic toxicity of DCNB which is detoxified by the hepatic GST system. Although UDCA has been shown to exert hepatoprotective effects in experimental animals and humans in the past, to the best of our knowledge, the present study is the first report that UDCA reduces the systemic toxicity of a toxicant which is detoxified by the hepatic GST system. Although a direct proof is not available, it is most likely that the reduction of the systemic toxicity of DCNB was achieved by the increase in GST activity caused by UDCA feeding. This finding may open a new research field with regard to the unique biological properties of this bile salt in modulating hepatic detoxifying enzymes.

(-)deprenyl increases activities of superoxide dismutase and catalase in certain brain regions in old male mice

A subcutaneous continuous infusion of (-)deprenyl for 3 weeks in old C57BL male mice increased superoxide dismutase (SOD) and catalase (CAT) activities in s. nigra, striatum and cerebral cortex but not in hippocampus, cerebellum or liver. The doses of 0.5 and 1.0 mg/kg/day were most effective, while with a higher dose (2.0 mg/kg/day), deprenyl tended to lose its effect slightly and with a lower dose (0.25 mg/kg/day) deprenyl was clearly less effective. The results suggest that deprenyl can increase antioxidant enzyme activities in certain brain regions in mice as was previously demonstrated in rats of both sexes and different ages; this raises the possibility that deprenyl has this particular effect in animal species other than rats.

Tauro alpha-muricholate has a biliary transport maximum (Tm) value equivalent to that for tauroursodeoxycholate and tauro beta-muricholate in the rat

Our previous studies have shown that Tm values for tauroursodeoxycholate (TUDC) and tauro beta-muricholate (T beta-MC) are more than two-fold higher than that for taurocholate (TC) in the rat. The present study attempted to clarify whether tauro alpha-muricholate (T alpha-MC) also has such an unusually large Tm value in the rat. Under nembutal anesthesia, male Wistar derived rats (body weight 280-300 g, 13 wks in age) were continuously infused with T alpha-MC solution. The infusion rate was raised stepwise every 20 min, until the bile flow began to decline. Bile was collected every 10 min and bile salt excretion rate was determined. The average of the highest three excretion values was assumed to be the Tm in each animal. The Tm value of T alpha-MC was found to be 2.86 +/- 0.36 mumol/min/100 g (mean +/- SD, n = 4), which was even greater than Tm values for TUDC (2.59 +/- 0.39 mumol/min/100 g, n = 4) and T beta-MC (1.93 +/- 0.31 mumol/min/100 g, n = 4) as we reported previously. The relationship between the bile flow rate (microliter/min/100 g, Y axis) and bile salt excretion rate (mumol/min/100 g, X axis) was highly linear [Y = (6.00 +/- 0.29) x +(6.60 +/- 1.88), P < 0.001, r = 0.95, n = 54]. The slope value for T alpha-MC (6.00 +/- 0.29 microliters/mumol) was significantly higher than that for TUDC (4.76 +/- 0.71 microliters/mumol) and was comparable to that for T beta-MC as we previously found for these bile salts in this rat strain. The results suggest that T alpha-MC has a very efficient transport system in this species as was observed for the other two bile salts that have a 7 beta-hydroxy group (TUDC and T beta-MC). This efficient transport system thus appears to be shared not only by bile salts specifically having a 7 beta-hydroxy group, but also by other bile salts such as T alpha-MC that have a 6 beta-hydroxy group but not a 7 beta-hydroxy group.

[Antibiotic prophylaxis for transurethral resection of the prostate--comparison of oral administration therapy with intravenous administration therapy]

To compare the prophylactic effect of oral and intravenous antibiotics against postoperative fever and urinary tract infection (UTI) after transurethral resection of the prostate (TUR-P), we conducted a multi-center prospective randomized study. The incidence of pyrexia over 38 degrees C was defined as the primary endpoint. One hundred and fifty patients with sterile urine before TUR-P were entered into this study. The patients were allocated randomly into the two arms; arm A cefotiam 4 g a day for 7 days, arm B tosufloxacin 300 mg a day for 7 days, based on the stratification into the 4 groups determined with/without preoperative indwelling catheters and with/without the history of preoperative UTI. Of these patients, 143 were eligible. We divided 124 patients without preoperative UTI and without indwelling catheters as the "low risk group", and the other 19 patients with preoperative UTI and/or with indwelling catheters as the "high risk group". In the low risk group, 9 patients out of 63 (14.3%) in arm A and 6 out of 61 (9.8%) in arm B had pyrexia during 7 postoperative days. The incidence of fever in arm B was 4.4% less than that in arm A and the 95% confidence limit was from -7% to 16%. In the high risk group, 4 out of 11 (36.4%) patients in arm A and none of 8 in arm B had fever but the difference was not significant. The incidence of post operative UTI in the low risk group on the 4 to 5, 9 to 12, 23 to 26 and 37 to 40 postoperative days was 8.3, 16.4, 25.0 and 23.9% in arm A and 6.7, 16.7, 29.6 and 36.7% in arm B, respectively. The prophylactic effect of oral administration of tosufloxacin is equivalent to that of the intravenous administration of cefotiam. The use of oral antibiotics is beneficial to reducing the cost of medication.

Taurine conjugate of ursodeoxycholate plays a major role in the hepatoprotective effect against cholestasis induced by taurochenodeoxycholate in rats

Rats which were taurine-deprived through beta-alanine administration and untreated rats were used to elucidate the mechanism of hepatoprotective effects of ursodeoxycholate (UDC). Animals were infused with taurochenodeoxycholate (TCDC, 0.4 mumol.min-1.100 g-1) alone or in combination with tauroursodeoxycholate (TUDC), or with UDC (both 0.6 mumol.min-1.100 g-1) for 2 h. Ursodeoxycholate as well as TUDC prevented severe cholestasis and liver damage induced by TCDC infusion in both untreated and taurine-deprived rat groups. In untreated rats, however, UDC was less effective in hepatoprotection than TUDC as indicated by sequential changes in biliary LDH output during the period of 30 to 120 min (P < 0.05). In rats receiving UDC and TCDC, total biliary output of LDH for 2 h was significantly higher in taurine-deprived rats than that in the control (73.40 +/- 10.10 vs 41.14 +/- 12.56: P < 0.05), suggesting that the difference became greater upon taurine deprivation. In contrast, in rats receiving TUDC and TCDC, the protective effect was comparable for the taurine-deprived and untreated rats. When the animals were infused with UDC and TCDC, taurine-deprived rats exhibited a biliary excretion rate for TUDC half that of control rats (P < 0.05). Furthermore, a highly significant correlation was observed between the biliary excretion rate of TUDC and biliary output of LDH (r = -0.886, P < 0.0001). These results suggest that UDC conjugates, especially TUDC, and not UDC may play a major role in the prevention of cholestasis and liver cell damage caused by TCDC infusion.

[A case of bilateral synchronous renal cell carcinoma treated with partial nephrectomy with temporary occlusion of the segmental renal artery (segmental nephrectomy)]

We present a case of bilateral synchronous renal cell carcinoma. A 57-year-old man visited our hospital with a complaint of fever up. On ultrasonography and computerized tomography scan, a round tumor about 2.5 cm in diameter in the posterior portion of the right kidney and another tumor about 7 cm in diameter arising from the upper pole of the left kidney. Selective renal arteriogram showed that the inferior branch of the posterior segmental artery supplied blood to the right renal tumor. Left partial nephrectomy with temporary occlusion of the main renal artery and posterior segmental nephrectomy of the right kidney were performed at the same time. In patients with cancer confined to the posterior segment of the kidney, segmental nephrectomy can be performed while allowing unimpaired perfusion to the remainder of the kidney from the main renal artery.

Nucleotide sequence of the Mn-stabilizing protein gene of the thermophilic cyanobacterium Synechococcus elongatus

The nucleotide sequence of the psbO gene encoding the extrinsic 33 kDa protein (the Mn-stabilizing protein) from the thermophilic cyanobacterium Synechococcus elongatus was determined. The deduced amino acid sequence consisted of 272 residues; 26 for the signal peptide and 246 for the mature protein. The amino acid sequences of nine proteolytic peptides from the isolated protein completely agreed with the deduced amino acid sequence. Several unique variations of amino acids were found in the primary structure, of which some may be related to the high thermostability of the protein.

Chronic treatment of (-)deprenyl prolongs the life span of male Fischer 344 rats. Further evidence

Seventy male Fischer 344 (F-344) rats were treated with s.c. injection of (-)deprenyl (0.5 mg/kg, n = 35) or physiological saline (n = 35) 3 times a week from the age of 18 months until the time of their natural death. The fifty percent survival time was 28 months in control animals and 30 months in the deprenyl treated group. The mean survival time after the start of treatment (18 months) and after 24 months were 378.3 +/- 97.4 days (mean +/- SD) and 196.3 +/- 97.4 days, respectively, in deprenyl treated rats and 328.7 +/- 108.8 days and 146.7 +/- 108.7 days in control rats. The increases in average life expectancies caused by deprenyl treatment (15% from 18 months and 34% from 24 months) were both statistically significant (P < 0.05, two-tailed t-test). The average body weights were comparable for both groups but the variation of body weight was greater in control groups, thus excluding the possibility that the life prolonging effect of deprenyl results from reduced dietary intake. The results confirm those of two previous studies (1,2) which reported a significant life prolonging effect of deprenyl in aged rats and lend added support to the results of a study on male F-344 rats where the effect was only marginally significant (16% increase after 24 months, P = 0.048 by one-tailed t test) (2).