Value of heptyl-beta-D-thioglucoside, a new nonionic detergent, in studies on membrane proteins

A new nonionic detergent, heptylthioglucoside, was synthesized and found to be more soluble than octylthioglucoside in water at low temperatures. Use of this detergent for solubilization and reconstitution of membrane proteins of Escherichia coli was examined. Heptylthioglucoside was as effective as octylthioglucoside and octylglucoside in solubilizing membrane proteins, and by the heptylthioglucoside-dilution procedure the H+-translocating ATPase (F1F0) and melibiose carrier could easily be reconstituted into liposomes. It is concluded that heptylthioglucoside is very useful in studies on membrane proteins.

Intestinal absorption mechanisms of gamma-butyrolactone-gamma-carbonyl-L-histidyl-L-prolinamide citrate (DN-1417) and thyrotropin-releasing hormone (TRH)

The absorption mechanisms of gamma-butyrolactone-gamma-carbonyl-L-histidyl-L-prolinamide citrate (DN-1417) and thyrotropin-releasing hormone (TRH) were studied in the rat. In situ absorption experiments were carried out by the radioimmunoassay, and experiments using everted sacs of small intestine were by radioactivity measurements with 14C-labeled DN-1417 or 3H-labeled TRH in the low concentration range of drug and by a high pressure liquid chromatography in the rather high concentration range of drug. The site specificity of absorption in the small intestine of rats could not be found with DN-1417, whereas TRH-T was absorbed from only the upper part of small intestine. Dose-proportional absorption of DN-1417 was observed in experiments of in situ as well as in vitro. Dose-proportional transfer of DN-1417 through the everted small intestine was also found within the concentration range from 120 ng/ml to 27 mg/ml, whereas the transfer ratio of TRH decreased with increase in the concentration of TRH. DN-1417 transfer from mucosal to serosal fluid was not inhibited by the replacement of medium Na ions by K ions, pretreatment of intestinal mucosa with HgCl2, the existence of an oligopeptide, or the existence of beta-lactam antibiotics which had been reported to be absorbed by active transport or carrier-mediated transport systems. While, TRH transfer was inhibited by the replacement of medium Na ions by K ions, pretreatment of intestinal mucosa with HgCl2, the existence of an oligopeptide, and the existence of beta-lactam antibiotics.(ABSTRACT TRUNCATED AT 250 WORDS)

Recent developments in the organic synthesis of lipid A in relation to biologic activities

For elucidation of a relationship between chemical structure and biologic activity of lipid A, syntheses of 13 derivatives of glucosamine beta (1-6) disaccharide, which were acylated at 3, 4, and 6'-hydroxyl groups and/or phosphorylated at positions 1 and 4', were carried out. The results showed the importance of the presence of the phosphate group at either position 1 or 4' and of the beta-hydroxyl group in acyl function, particularly in N-linked fatty acids, for the exhibition of biologic activities characteristic of lipid A. New evidence on the positions of fatty acids in natural lipid A of Escherichia coli species obtained by means of 2D-H nuclear magnetic resonance was also demonstrated; the findings indicate that the 3'-hydroxyl group is acylated and the 6'-hydroxyl group in the molecule must be free.

Nucleotide sequence of the promoter region of the melibiose operon of Escherichia coli

The nucleotide sequence of the promoter region of the melibiose operon of E. coli was determined. Consensus sequences for the -35 region, the Pribnow box and the binding site for cyclic AMP receptor protein were found in this region. The possible secondary structure of this DNA region was very similar to that of the promoter region of the lactose operon. A possible initiation ATG preceded by a Shine-Dalgarno sequence with proper spacing was present just downstream of the promoter region. The possible sequence of 52 amino acid residues in the NH2 terminus of the alpha-galactosidase were determined.

Nucleotide sequence of the melB gene and characteristics of deduced amino acid sequence of the melibiose carrier in Escherichia coli

The nucleotide sequence of the melB gene coding for the melibiose carrier in Escherichia coli has been determined. The melibiose carrier is predicted to consist of 469 amino acid residues, resulting in a protein with a molecular weight of 52,029. The predicted carrier protein is highly hydrophobic (70% nonpolar amino acid residues). The hydropathic profile suggests that there are 10 long hydrophobic segments in the primary structure of the carrier protein. Most of them seem to traverse the membrane. Although the hydropathic profile of the melibiose carrier is similar to that of the lactose carrier as a whole, homology in the primary structure between the two carriers is very low. Furthermore, no homology in the nucleotide sequence is found in the structural genes for the two carriers. However, the nucleotide sequences of the intergenic regions are very similar between the melibiose operon and the lactose operon. There is a typical intercistronic regulatory sequence in the 3'-flanking region of the melB as well as in that of the lacY, which suggests the presence of another gene downstream of the melB.

Vaginal absorption of a potent luteinizing hormone-releasing hormone analogue (leuprolide) in rats. IV: Evaluation of the vaginal absorption and gonadotropin responses by radioimmunoassay

The vaginal absorption of leuprolide (a potent luteinizing hormone-releasing hormone analogue), which has the potential for producing regression of hormone-dependent tumors as well as high gonadotropin-releasing and ovulation-inducing activities, was evaluated in rats by radioimmunoassay. Gonadotropin (luteinizing hormone and follicle-stimulating hormone) release was concomitantly determined. Although leuprolide disappeared rapidly from the serum after intravenous administration (the biological half-lives were 8.4 min in the alpha-phase and 33.2 min in the beta-phase), long-lasting serum levels were observed when the analogue was administered vaginally. The vaginal absorption was enhanced by adding citric acid to the test solution. The absolute bioavailability, estimated by the AUC of serum leuprolide levels, was 25.8% over 6 h and 38.0% over 12 h in the 5% citric acid solution (pH 3.5). The sustained release of gonadotropin was also obtained after vaginal administration of the analogue. A linear dose absorption correlation of leuprolide was obtained in the range of 10-1000 micrograms/kg in an aqueous solution or methylcellulose jelly. The release of gonadotropin showed a plateau level at greater than 10 micrograms/kg, which corresponds to an effective dose for antitumor activity. The vaginal absorption of leuprolide varied with the estrous cycle, but this effect was eliminated by prior subcutaneous pretreatment with the analogue.

A collaborative study of stroke incidence in Japan: 1975-1979

A Japan Collaborative Study of Stroke covering 20 regional and occupational population groups was conducted with the support of the Ministry of Health and Welfare. In this study 17,423 males and 16,856 females, aged 40 to 69, were followed up prospectively from 1975 to 1979. The average annual incidence of all types of stroke was 3.94 for men and 2.52 for women per 1,000 population. The incidence of cerebral hemorrhage for men and women stood at 1.26 and 0.59 and that of cerebral infarction at 1.87 and 1.10 respectively. The difference in incidence between the sexes was large particularly in the age range of 40-49. The incidence of all types of stroke, cerebral hemorrhage and cerebral infarction increased with age. The incidence of all strokes in Japan during the period 1975-1979 appears to have decreased in comparison with that in 1960-1969, but tended to be still higher than that in Western countries.

Alcohol intake and hypertension among urban and rural Japanese populations

A significant positive relationship was found between alcohol intake and blood pressure for men 40-69 years old living in urban Osaka (492 men) and in rural Akita (395 men), Japan, surveyed from 1975 to 1977. Both mean blood pressure and the prevalence of hypertension were related to alcohol intake in a graded fashion. Stepwise multiple regression also showed that both systolic and diastolic pressure were associated with alcohol intake independent of ponderosity index, serum cholesterol, triglycerides, hemoglobin, uric acid, smoking, and age. This cross-sectional study indicates a continuous--and not a threshold--relationship between alcohol and blood pressure, with the effect of even moderate consumption, e.g. 28-55 g per day (equivalent to about 2-4 U.S. drinks per day).

Desensitization of gonadotropin-releasing response following vaginal consecutive administration of leuprolide in rats

The vaginal absorption of a potent luteinizing hormone-releasing hormone analog (leuprolide), and the gonadotropins (luteinizing hormone and follicule-stimulating hormone)-releasing response after continuous vaginal and subcutaneous administration of the analog to rats were determined by the radioimmunoassay. A marked suppressive effect on the gonadotropin-releasing response along with long-lasting serum levels of leuprolide were paradoxically observed after consecutive 3-d vaginal administration of the analog at doses of 1 microgram/kg or greater. Pituitary function recovered progressively with cessation of the treatment but was not complete 4 d after cessation. Continuous vaginal and subcutaneous infusion resulted in an almost complete inhibition of both gonadotropins response. It is suggested that effective desensitization of the pituitary gonadotropin response is elicited by continuous administration of leuprolide and, therefore, the vaginal administration resulting in prolonged serum levels of the analog could be preferable as a self-administration method for medical treatments such as anti-tumor therapy and birth control.

Patulin biosynthesis: enzymatic and nonenzymatic transformations of the mycotoxin (E)-ascladiol

A mycotoxin, (E)-ascladiol, was established as a direct precursor of patulin in cell-free preparations of Penicillium urticae patulin-minus mutants J1 and S11, but not S15. Isomerization to a side product, (Z)-ascladiol, was nonenzymatically catalyzed by sulfhydryl compounds.

Correlation of the bioavailability of diazepam from uncoated tablets in beagle dogs with its dissolution rate and bioavailability in humans

The bioavailability of diazepam (I) in uncoated tablets in beagles was tested using tablets tested previously in humans. The correlations of the dissolution rates and bioavailabilities of these tablets in humans and beagles were examined. The plasma level of N-desmethyldiazepam (II), the main metabolite of I, was used as an index of bioavailability after p.o. administration of uncoated tablets of I, because I is rapidly metabolized. Thus the plasma level of I is very low, and AUCs (areas under plasma level-time curves) calculated from plasma levels of II were related to the dose of I (2-10 mg). With different tablets, the rates and extents of bioavailability of I differed significantly in beagles, but only the rate of bioavailability showed significant differences in humans. The rank orders of tablets, based on the blood levels of II soon after p.o. administration of the tablets were the same, but other parameters of bioavailability of I in the tablets were quite different in beagles and humans. Consequently, there was no significant correlation between the bioavailabilities of I in beagles and humans. The gastric fluid of beagles is almost neutral, and the bioavailabilities of the tablets in beagles correlated well with the dissolution rates of I determined at pH 4.6, but not at pH 1.2. The differences in the bioavailabilities of I in humans and beagles were attributed to differences in transit time in the gastrointestinal tract and/or in the volume of the gastrointestinal fluid.

Dietary intake and serum total cholesterol level: their relationship to different lifestyles in several Japanese populations

Serum total cholesterol level and dietary intake were surveyed 1975--1977 in six Japanese population groups with different lifestyles, including groups in both rural (Akita and Kochi) and urban (Osaka) areas. Clerical workers in Osaka, who had the most westernized lifestyle of all the study groups, had the highest mean serum total cholesterol level (202 mg/dl for men ages 40--49 and 50--59 years), while farmers in Akita had the lowest mean serum total cholesterol level (163 mg/dl for men 40--49 years old, 159 mg/dl for men 50--59 years old, 165 mg/dl for men 60--69 years old). Nutrient intake data for mean ages 40--59 years showed 23% of calories from fat for clerical workers in Osaka, the highest among the study groups, whereas farmers in Akita showed a low level of 14%. The ratio of dietary polyunsaturated to saturated fatty acids was over 1.1 for all groups. Cholesterol intake was 339--487 mg/day. Total carbohydrate as a percentage of calories was 53--65%; 75--80% of carbohydrate energy was ingested from cereals. Sugar accounted for less than 3.5% of total calories. In the cross-group correlation analysis between dietary lipid intake and serum total cholesterol, a significant strong positive correlation was found between the dietary lipid factor (phi) of Keys et al. and the mean serum total cholesterol level. A weak but significant correlation was observed between the dietary lipid factor and serum total cholesterol for individual inhabitants of Osaka.

Serum total cholesterol, triglyceride level, and dietary intake in Japanese students aged 15 years

The authors surveyed serum cholesterol and triglyceride levels in 238 male and 217 female students aged 15 years in Osaka, Japan, in 1977, as well as dietary intake, using a 24-hour record in 81 male and 61 female students. Serum cholesterol and triglyceride levels of Japanese students were 163.6 mg/dl and 81.7 mg/dl, respectively, for males, and 182.2 mg/dl and 78.9 mg/dl for females. For female students, those who participated in a school sports club regularly during the previous three years had cholesterol levels 10 mg/dl lower than the subjects who had not participated in a sports club; these active students also had smaller skinfold thickness, although there was no difference in other anthropometric measurements. Although the dietary intake of Japanese students was found to be westernized, compared with that of Japanese adults, Japanese students reported low fat intake (25-30% of energy), high polyunsaturated/saturated fatty acid ratio (1.1-1.2), and high carbohydrate intake (55-61% of energy), differing considerably from US students.

Multivariate analysis of risk factors for stroke. Eight-year follow-up study of farming villages in Akita, Japan

Akita Prefecture has an especially high mortality rate from stroke, and its age-adjusted death rate from stroke is the highest in Japan. We have carried out an epidemiological survey of cardio- and cerebrovascular diseases (CVD) in farming villages in this prefecture since 1963, with a response rate of 84%. During our 8-year follow-up, 94 new stroke cases were observed among 1,814 subjects. Multiple logistic function analysis was carried out on nonstroke and stroke cases from subjects aged 40 to 69 years at time of initial examination, in order to clarify the risk factors for stroke. The analysis used eight variables: age, sex, systolic blood pressure, obesity index, urinary sugar, urinary protein, serum total cholesterol, and total protein. The results showed that hypertension was the most important risk factor for stroke. However, regarding cholesterol, multivariate analysis showed that among men and women aged 40 to 69 years at entry, subjects with low serum total cholesterol levels were more prone to cerebral hemorrhage, but that serum cholesterol level had no weight as a risk factor for cerebral infarction. These results correspond well with the observed fact that stroke incidence or death rate in Japan is higher in populations with high prevalence of hypertension and low concentration of cholesterol, and also with the fact that death rate from hemorrhage declines with the increment of serum total cholesterol and the westernization of diet.