Two new reactive targets of 2,5-hexanedione in vitro – beta-alanine and glycine

In this study, we found that two amino acids reacted with 2,5-hexanedione to form new reaction products in vitro, respectively. In the reaction of beta-alanine and 2,5-hexanedione, a reaction product was obtained and analyses of obtained results showed it was 3-(2,5-dimethyl-1H-pyrrol-1-yl)propanoic acid; in the reaction of glycine and 2,5-hexanedione, a reaction product was also obtained and analyses showed it was (2,5-dimethyl-1H-pyrrol-1-yl)acetic acid. Two reaction products were found to be oxidized easily; in addition, the latter was more easily to be oxidized than the former in the air. Our discoveries demonstrated that reactions between amino acids and 2,5-hexanedione could exist possibly in vitro. At present, it is clear that 2,5-hexanedione causes either axon atrophy or swelling, but the underlying molecular mechanism is still unclear. Since both beta-alanine and glycine are considered as neurotransmitter in the central nervous system, the reaction products remain to be identified in vivo.

Fertilization rates of small-head sperm in conventional IVF and ICSI

Five men produced 23 ejaculates in 23 assisted reproductive technology cycles for semen analysis. In 11 of the 14 ICSI cycles and in 5 of the 9 IVF cycles, small-head sperm were found in more than 70% of the cells, having a length of < 3.5 micro m and a width of < 2 micro m. In 6 of the 14 ICSI cycles, the embryologist who performed the ICSI was not alerted to e presence of small-head sperm. Subsequent fertilization rate was significantly lower than a) the fertilization rate of the remaining 5 ICSI cycles that acted as a control, in which the embryologist was alerted to the presence of small-head sperm, and b) was lower than the 3 ICSI cycles with normal sperm head (p < .05). The 8 cell embryo and blastocyst rates in the former group were also decreased, although not significantly, compared to the latter groups. Likewise, in the 5 IVF cycles with small-head sperm, the fertilization rate was significantly lower than in the 4 IVF with normal sperm head (p < .05). Embryologists should be alerted when a high percentage of small-head sperm are detected during routine semen analysis because they may be associated with reduced fertilization and embryo outcome.

Long-term treatment with sterigmatocystin, a fungus toxin, enhances the development of intestinal metaplasia of gastric mucosa in Helicobacter pylori-infected Mongolian gerbils

BACKGROUND

Helicobacter pylori is a human gastric carcinogen. Sterigmatocystin (ST), a fungus toxin, is a risk factor of gastric cancer. Cytotoxin-vacuolation toxin A (VacA) present in supernatants of H. pylori suspensions can cause gastritis and ulcer. The aim of this study was to examine the effects of H. pylori, ST and VacA in Mongolian gerbils.

METHODS

Male Mongolian gerbils (n = 196) were treated with H. pylori supernatants (10 ml/1000 mg) mixed with diet or inoculated intragastrically with H. pylori alone or with ST (100 or 1000 ppb), and then killed 27 months later. Gastric tissue sections were stained with haematoxylin and eosin (H&E), periodic acid-Schiff (PAS), Alcian blue (AB, pH 2.5) and with immunostaining for PCNA and p53 expression.

RESULTS

In H. pylori-infected gerbils, the normal mucosa was replaced by hyperplastic epithelium. Severe gastritis, cystic dilatation of gastric glands, hyperplastic polyps and intestinal metaplasia were observed. In H. pylori + ST (1000 ppb) gerbils, intestinal metaplasia was significantly more frequent than in H. pylori alone animals. No pathological changes were observed in the H. pylori supernatant group. Osseous metaplasia was observed in the H. pylori + ST (100 ppb) group. Serum gastrin levels of the H. pylori + ST (1000 ppb) group were significantly higher than those of the other groups. PCNA labelling index and p53 index of infected gerbils were significantly higher than those of uninfected groups.

CONCLUSION

H. pylori causes gastritis, ulcer and intestinal metaplasia. ST enhances the development of intestinal metaplasia and increases gastrin levels in H. pylori-infected Mongolian gerbils.

Long-term Treatment with Sterigmatocystin, a Fungus Toxin, Enhances the Development of Intestinal Metaplasia of Gastric Mucosa in Helicobacter pylori-infected Mongolian Gerbils

BACKGROUND

Helicobacter pylori is a human gastric carcinogen. Sterigmatocystin (ST), a fungus toxin, is a risk factor of gastric cancer. Cytotoxin-vacuolation toxin A (VacA) present in supernatants of H. pylori suspensions can cause gastritis and ulcer. The aim of this study was to examine the effects of H. pylori, ST and VacA in Mongolian gerbils.

METHODS

Male Mongolian gerbils (n = 196) were treated with H. pylori supernatants (10 ml/1000 mg) mixed with diet or inoculated intragastrically with H. pylori alone or with ST (100 or 1000 ppb), and then killed 27 months later. Gastric tissue sections were stained with haematoxylin and eosin (H&E), periodic acid-Schiff (PAS), Alcian blue (AB, pH 2.5) and with immunostaining for PCNA and p53 expression.

RESULTS

In H. pylori-infected gerbils, the normal mucosa was replaced by hyperplastic epithelium. Severe gastritis, cystic dilatation of gastric glands, hyperplastic polyps and intestinal metaplasia were observed. In H. pylori + ST (1000 ppb) gerbils, intestinal metaplasia was significantly more frequent than in H. pylori alone animals. No pathological changes were observed in the H. pylori supernatant group. Osseous metaplasia was observed in the H. pylori + ST (100 ppb) group. Serum gastrin levels of the H. pylori + ST (1000 ppb) group were significantly higher than those of the other groups. PCNA labelling index and p53 index of infected gerbils were significantly higher than those of uninfected groups.

CONCLUSION

H. pylori causes gastritis, ulcer and intestinal metaplasia. ST enhances the development of intestinal metaplasia and increases gastrin levels in H. pylori-infected Mongolian gerbils.

Stomach cancer-related mortality rate is higher in young Japanese women than in men

This study compares stomach cancer-related mortality rates in Japan with those in European and Asian countries and analyzes trends in stomach cancer-related mortality rates according to gender in young Japanese over the period of 1957-1997. From official death certification numbers and population estimates, we obtained stomach cancer-related mortality rate for all ages and various ages according to gender. Japan's ranking compared to other countries in death percentage of all cancers which are attributable to stomach cancer was fourth for both men and women. In Japan and Ireland, total elimination of deaths from stomach cancer in men resulted in increased life expectancy of 0.68 and 0.22 y respectively, whereas the corresponding figures for women were 0.42 and 0.14 y respectively. The sex ratios of stomach cancer-related mortality rates were 0.75, 0.63, 0.80 and 0.94 for 25-29, 30-34, 35-39 and 40-44 y age groups, respectively, in 1997. The sex ratio of relative risk ranged from 0.62 to 0.92 in 25-40 y age groups during the observation period. The life expectancy in 30-34 y age group increased by 0.66 y for men and 0.41 y for women in 1995 after elimination of stomach cancer-related deaths. Our results suggest that stomach cancer-related mortality rates are still high in Japan and young women are at higher risk of stomach cancer-related death relative to young men and that sex ratio is stable or slightly decreased over the 40-y period. It is important to monitor this trend continuously in the next few years.

Stomach cancer-related mortality

In Japan stomach cancer remains the leading cause of cancer-related mortality. We analysed the annual mortality rate of stomach cancer in relation to age, gender and life expectancy in Japan between 1970 and 1995. The adjusted stomach cancer-related mortality rates decreased from 88.9 in 1970 to 45.4 per 100,000 in 1995 in males and from 46.5 to 18.5 per 100,000 in females. The male-female ratio for stomach cancer-related mortality in all ages was 1.9-2.5 during this 25-year period, and the mortality rate was higher in females than in males at young age. The negative contribution to life expectancy for stomach cancer in males was 0.65 years and 0.42 years in females, which is consistent with a higher mortality rate in males. This negative contribution was 41.8% of total cancer in 1970 and 39.4% in 1995 in males and 34.4% and 16.0%, respectively, in females. Our results demonstrated the need to take into consideration the characteristics of stomach cancer in young women and the effects of ageing when designing programmes aimed at prevention and control of this malignancy.

Absence of p53-mediated G1 arrest with induction of MDM2 in sterigmatocystin-treated cells

P53 plays a critical role in G1 checkpoint after DNA damage. MDM2 gene is a p53 target gene and its protein forms a feedback loop with p53 and inhibits p53-mediated G1 arrest. Sterigmatocystin (ST) is a mycotoxin and carcinogen. In this study we show that exposure of cells to ST for 12 or 24 h resulted in failure of G1 arrest at both time points. Accordingly, p53 protein was not increased and p21WAF1 expression was inhibited at 12 h, and both proteins were weakly induced at 24 h after treatment with ST. Meanwhile, MDM2 protein was induced in a p53-dependent fashion by ST at both 12 and 24 h. The induction of MDM2 was coincident with the cellular responses of p53 and p21WAF1, and might contribute to the failure of G1 arrest in ST-treated cells. In addition, ST-treated cells exhibited G2M arrest, regardless of p53 status. Our results indicate that the carcinogenic effects of ST seem to be mediated by failure of p53-mediated G1 checkpoint.

Effect of distance and population size on patient trips in a prefecture of Japan: Application of a transportation distribution model to the demand for and supply of health services

The gravity model, a method for analyzing transportation distribution in transportation engineering, was used to explain patient trips between ten health service regions in a Japanese prefecture. The OD (Origin-Destination) tables were constructed with zoning by regions, distinguishing between out- and inpatients. The observed trips were determined from the data of a survey conducted in 1992 that reported the locations of patient residences and chosen medical facilities.The base values used in the model calculations were the population size of each region and the road distance between the centers of regions. Problems of intrazonal trip were avoided by setting a mean intrazonal movement distance.This model was calibrated by the linear regression method with simultaneous validation by the index of correlation coefficients. The model was found to accurately simulate the effect of distance on the choice of medical facilities and the differences between the characteristics of in- and out-patients. The population value in use showed the relation not only with demand but also the supply of clinical services. It was suggested that the model presented here was useful in the allocation of medical resources and would help explain the relationship between suppliers and consumers of medical services.

Relationship between 2,5-hexanedione concentrations in nerve, serum, and urine alone or under co-treatment with different doses of methyl ethyl ketone, acetone, and toluene

To ascertain the relationship among 2,5-hexanedione (2,5-HD) concentrations in nerve, serum and urine, rats were injected subcutaneously with 2.6 mmol/kg 2,5-HD alone, or together with 2.6 or 13.0 mmol/kg of methyl ethyl ketone, acetone and toluene. 2,5-HD concentrations in sciatic nerve (NC), serum (SC) and urine (UC) were determined, and the linear regression between each two of NC, SC, and UC were calculated. There was good correlation between NC and SC, SC and UC in the 2,5-HD alone group, and good correlation between NC and SC in the co-treated groups. Co-treatment solvent had little effect on the relationship between SC and NC. 13.0 mmol/kg co-treated solvent tended to decrease the regression coefficients compared with 2.6 mmol/kg co-treated solvent. These results show that SC can be used in estimating NC in the 2,5-HD alone or co-treated groups, and UC can be used in estimating SC in the 2,5-HD alone group.

Effects of methyl ethyl ketone, acetone, or toluene coadministration on 2,5-hexanedione concentration in the sciatic nerve, serum, and urine of rats

OBJECTIVE

To clarify changes in the serum, nerve, and urinary levels of 2,5-hexanedione (2,5-HD) in rats on coadministration with methyl ethyl ketone (MEK), acetone (AC), and toluene (TO).

METHOD

2,5-HD alone or combined with MEK, AC, and TO was injected subcutaneously into a total of 306 male Wistar rats. The rats were divided as follows into 7 groups: (1) 2.6 mmol/kg 2,5-HD alone (HD) and (2) 2.6 mmol/ kg 2,5-HD combined with 2.6 mmol/kg MEK (HD + MEK), (3) with 2.6 mmol/kg AC (HD + AC), (4) with 2.6 mmol/kg TO (HD + TO), (5) with 13.0 mmol/kg MEK (HD + 5MEK), (6) with 13.0 mmol/kg AC (HD + 5AC), and (7) with 13.0 mmol/kg TO (HD + 5TO). 2,5-HD concentrations in the serum, sciatic nerve, and urine of rats were determined within 16 h of the injections and pharmacokinetic parameters were estimated.

RESULTS

It was observed that (1) the 2,5-HD concentration and AUC value (area under concentration versus time curve) determined in the serum and nerve increased significantly in the cotreated groups as compared with the HD group; (2) the effect MEK had in elevating the 2,5-HD concentration and AUC in the serum and nerve was stronger than that of AC, and the effect AC had was stronger than that of TO; (3) a. dose increase from 2.6 to 13.0 mmol/kg for MEK and AC induced further increases in the 2,5-HD concentration and AUC determined in the serum and nerve; (4) elimination constants recorded for 2,5-HD (Ke) from the serum and nerve decreased in all the cotreated groups, and the degree of the decrease correlated inversely with the elevation in 2,5-HD concentration and AUC in the serum and nerve; and (5) urinary 2,5-HD concentrations measured in the 13.0-mmol/kg cotreated groups increased in parallel with the elevation in serum 2,5-HD concentrations.

CONCLUSION

Coadministration of 2,5-HD with MEK, AC, or TO can increase the concentration and AUC of 2,5-HD in serum and the sciatic nerve, and these increases can be further enhanced by an increase in the concomitant doses of MEK and AC.

Evaluation of cutoff levels for screening of gastric cancer using serum pepsinogens and distributions of levels of serum pepsinogen I, II and of PG I/PG II ratios in a gastric cancer case-control study

This study was carried out to determine the cutoff levels of serum pepsinogen (PG) I, II and their ratio of PG I/PG II for gastric cancer to establish a better screening system. Optimal cutoff levels for gastric cancer screening using serum pepsinogens were determined using Youden's index. The sensitivity, specificity and Youden's index for gastric cancer cases were calculated according to sex, age and the stage of gastric cancer, and the maximum Youden's index in each category was adopted as the cutoff level for gastric cancer screening using serum pepsinogens. The maximal Youden's index in all gastric cancer cases was 0.37, corresponding to a cutoff level of PG I < 40 (micrograms g/l) and PG I/PG II < 3.5. The sensitivity and specificity for gastric cancer cases of these cutoff levels were 0.50 and 0.87, respectively. In future, better criteria for gastric cancer screening have to be examined with the estimation of Youden's index in addition to other epidemiological methods such as ROC (receiver operating characteristic) curves and/or cost benefit analyses.

Different administration schedules of the same dose of 2,5-hexanedione influence the development of neuropathy and the toxicokinetics

The same total dose (1.2 g/kg/week) of 2,5-hexanedione (2,5-HD) was administered subcutaneously at 100 mg/kg/12 hr, 200 mg/kg/24 hr, and 400 mg/kg/48 hr to three groups of Donryu rats. The peripheral neuropathy induced by 2,5-HD was confirmed by clinical observation every day, and neurophysiological measurements every 4 weeks. During the 15th week of this experiment, 2,5-HD concentrations in plasma 0.5 to 24 hours after injection were determined. It was found that the greater the dose of 2,5-HD per treatment injected, the earlier peripheral neuropathy developed. Toxicokinetic analysis showed that both the values of the area under the plasma concentration versus time curve and the half life of 2,5-HD were increased, but the excretion parameters (Ke) were decreased, in animals treated with 200 mg/kg/24 hr and 400 mg/kg/48 hr 2,5-HD.

Influence of different doses of methyl ethyl ketone on 2,5-hexanedione concentrations in the sciatic nerve, serum, and urine of rats

Rats were injected subcutaneously with 2,5-hexanedione (2,5-HD 2.6 m mol/kg) alone (HD group) or with 2,5-HD and methyl ethyl ketone (MEK) (2.6 m mol/kg of each agent, HD&MEK group) or with 2,5-HD 2.6 m mol/kg and 5 times that dose (13.0 m mol/kg) of MEK (HD&5MEK group). The concentration of 2,5-HD in serum and in the sciatic nerve was determined 0.5, 1, 2, 4, 8, and 16 h after administration. Urinary 2,5-HD concentration was determined from the beginning of administration up to 16 h afterward. 1) The concentration of 2,5-HD in the serum, the sciatic nerve, and the urine was increased significantly (p < 0.05) in the co-administered groups; the higher the MEK doses were, the greater was the increase. 2) The clearance of 2,5-HD from both the serum and the sciatic nerve was delayed in the co-administered groups. The highest concentration in serum and the sciatic nerve appeared at 1 and 2 h respectively. After administration, the biological halflife (t1/2) of 2,5-HD from 1 to 8 h in serum was 6.5, 5.8 and 12.0 h for the HD, HD&MEK, and HD&5 MEK groups respectively. From 8 to 16 h, the t1/2 in serum was 1.2, 3.2 and 16.6 h for the HD, HD&MEK, and HD&5MEK groups, respectively. In nerve tissue, the prolongation of clearance in the co-administered groups was greater than that in serum, the t1/2 from 2 to 8 h being 5.2, 9.6 and 19.9 h for the HD, HD&MEK, and HD&5MEK groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

[Seroepidemiological study on hepatitis C virus infection in an endemic area of hepatitis C virus]

To clarify the prevalence of hepatitis C virus infection in a rural area with high incidence of chronic liver disease in Japan, sera from 412 inhabitants, aged 20-89 years, collected in 1989-1990 and sera from 483 inhabitants in the same area, collected in 1982 were tested for anti-HCV (antibody to C100-3) with the first-generation enzyme-linked-immunosorbent-assay (ELISA). In addition, sera from 118 inhabitants, aged 20-49 years, collected in 1989-1990 were tested for HCV-RNA with the polymerase chain reaction technique, with use of primers from the 5'-untranslated region of the HCV genome. Anti-HCV was positive in 175 out of 412 sera collected in 1989-1990 (42.5%): prevalence was higher in male (54.0%) than in female (34.9%). The prevalence rates in the 20-29, 30-39, 40-49, 50-59, 60-69, and 70-89 year-old group were 0%, 14.3%, 51.9%, 41.7%, 49.1%, and 53.1%, respectively. On the other hand, in sera collected in 1982, the overall prevalence of anti-HCV was 42.5% (175 of 412). The prevalence rates in the 20-29, 30-39, 40-49, 50-59, 60-69, and 70-89 year-old group were 12.5%, 43.3%, 51.5%, 50.3%, 60.7%, and 68.9%, respectively. The prevalence rate of young adults less than 40 years old in 1982 were higher than that in 1989-1990. In short, the prevalence of hepatitis C virus infection in this area had altered a great deal. HCV-RAN was detected in 42 of 118 (35.6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of serum antibody titers against hepatitis C virus core protein with clinical features by western blot (immunoblot) analysis using a recombinant vaccinia virus expression system

In order to study the relationships among the clinical features of hepatitis C patients, the presence of hepatitis C virus (HCV) RNA in their blood, and their serum antibody titers against the core protein of virus and to study the antibody levels in asymptomatic HCV carriers, a recombinant vaccinia virus containing a core protein gene was constructed. The recombinant virus expressed a protein with a molecular mass of 22 kDa in RK-13 cells as determined by Western blot (immunoblot) analysis. By using the cell lysate of virus-infected cells and serially diluted serum samples, core antibody titers in the groups of patients in the chronic hepatitis phase and in the convalescent phase as well as in asymptomatic carriers were determined by enhanced chemiluminescence Western blot analysis. Almost all patients in the chronic phase were shown to have high antibody titers of more than 1:500,000 and with no exception had of HCV RNA in their sera. On the other hand, patients who had recovered naturally and were in the convalescent phase were shown to have significantly lower antibody titers, and the antibody was not detected in the lowest serum dilution of 1:500 in 43% of these patients (three of seven total patients). Antibody levels of patients who showed a good response to interferon treatment decreased to intermediate levels between those of patients in the chronic phase and those of patients in convalescent phase. The antibody titers in asymptomatic carriers varied considerably from 1:500,000 to 1:500, and 41% (11 of 27 total individuals) of these carriers showed a high titer equivalent to that of those in the chronic phase. Core antibody was detected consistently in the individuals in whom HCV RNA was detected. This system for core antibody might be useful for identifying the stage of an apparent HCV infection.

[Distribution of serum pepsinogen I, II values and their ratios in residents of a rural area]

In order to adopt pepsinogen levels as a screening indicator of gastric cancer, the serum pepsinogen I (PG I) and serum pepsinogen II (PG II) levels were studied using one thousand samples from a rural area and their ratios PG I/PG II were calculated. Samples were collected by stratified random sampling of the residents in S town with a population of about 10,000. The collected data was statistically analyzed to determine distributions by respective categories of sex and age. The following results were obtained. 1. The distributions of PG I, PG II and their ratio PG I/PG II levels largely deviated from normal distributions. Therefore, it is recommended that non-parametrical method is used to analyze this data. 2. The median of PG I level (49.3 micrograms/l) in males was statistically higher than that (43.6 micrograms/l) in females. On the other hand, a statistically significant difference between males and females was not observed in either the PG II value or the ratio PG I/PG II, respectively. 3. The pattern for changes in PG I values with age was different between males and females. While PG I levels were almost constant until the sixties, after the seventies levels showed a marked decrease in male subjects. In female subjects, an age effect in levels was not observed for PG I. On the other hand, PG II levels increased with age except for age group seventies, and the PG I/PG II ratios showed a decreasing tendency in both males and females.

Duodenal hemorrhage and dermal vasculitis associated with mixed connective tissue disease

We describe a 23-year-old woman with mixed connective tissue disease (MCTD) who developed duodenal bleeding responsive to treatment with corticosteroid and recurrent skin eruptions due to leukocytoclastic vasculitis. The endoscopic findings revealed patchy, reddened, edematous, friable mucosa with scattered small ulcers and oozing of blood in the second portion of the duodenum. Endoscopic pictures from the onset to healing are presented. This appears to be the first recorded occurrence of such findings in MCTD.

[Ion chromatographic determination of inorganic anions in human serum]

The ion chromatographic method is a rapid and reliable technique for the simultaneous determination of inorganic anion concentrations in serum. We are investigating the effects of various diseases on the serum levels of the following inorganic anions: phosphate, bromide, nitrate, and sulphate. In this paper, we tested the intra- and intermeasurement reproducibility of the ion chromatographic method using pooled normal human serum. We found a good intrameasurement reproducibility for all of the above inorganic anions. The intermeasurement reproducibility was good for three of the inorganic anions but not for nitrate. We measured the serum levels of these inorganic anions in 241 inhabitants in one rural area. Using sera of normal inhabitants chosen from the above group, we used the mean value plus or minus two standard deviations as the normal range of each inorganic anion. Our values are in agreement with previously published reports. We found that the serum levels of nitrate and sulphate tended to be increased in inhabitants with liver or kidney disfunction respectively.

Angiotensinogen's role in ANG formation, renin release, and renal hemodynamics in isolated perfused kidney

Isolated perfused rat kidneys were used to investigate the effects of the addition of pure angiotensinogen or renin-free plasma to the perfusate on angiotensin I (ANG I) and angiotensin II (ANG II) generation, renal hemodynamics, and renin release. When no angiotensinogen or plasma is added, a very small amount of angiotensinogen is initially detected in the perfusate. Whereas renin secreted by the kidney accumulates in the perfusate, angiotensinogen disappears during the perfusion and immunoreactive ANG II cannot be detected. The addition of angiotensinogen reactivates the renin-angiotensin system. ANG I, [des-Asp1] ANG I, ANG II, and [des-Asp1] ANG II are progressively generated in the perfusate. At a constant perfusion pressure, as well as at a variable perfusion pressure, a progressive fall in renal perfusate flow is observed that is significantly correlated to the level of immunoreactive ANG II. ANG II significantly blunts the rise in renin, and renin release in the perfusate is negatively correlated to immunoreactive ANG II levels. Comparison of the ANG I and ANG II levels in in vitro incubated perfusates and circulated perfusates shows that in plasma-injected perfusates the level of immunoreactive ANG II is dependent on both the production of ANG I and its conversion to ANG II by renal and perfusate converting-enzyme activity, and on ANG I and ANG II degradation by the kidney and the perfusate.

Effects of cefbuperazone on the chemiluminescence of human neutrophils

To investigate the in vivo effect of antimicrobial agent on neutrophil chemiluminescence and serum opsonic activity, cefbuperazone sodium (CBPZ) was administered to healthy male volunteers via an intravenous drip. A peripheral blood sample (10 ml) was collected 7 times: prior to injection, then 1, 3, 6, 9, 12 and 24 h after injection. Neutrophil chemiluminescence and serum opsonic activity was measured by the simultaneous multiple measurement system based on luminol-dependent chemiluminescence and indicated by peak height and peak time. Neutrophils were activated at hour 1 from the point of view of peak height and statistical significance was observed. The fluctuation of serum opsonic activity was small and statistical significance was not observed. CBPZ has an in vivo effect on neutrophils which was not supposed from in vitro study.

Metabolism of bradykinin in isolated perfused rat kidney. Measurement of kininase activity in perfusate and urine

The effect of bradykinin and kininase on renal function and the metabolism of bradykinin in the kidney were examined in isolated perfused rat kidney. In this experimental system, exogenous bradykinin did not affect the water and electrolyte handling by the kidney. Most of bradykinin and kininase in urine were derived from kidney but not from circulating medium. Kininase II may not have a major role in bradykinin destruction by the kidney.

[Kallikrein secretion by the isolated perfused rat kidney. Role of perfusion pressure and the renin-angiotensin system]

The isolated perfused rat kidney (IPRK) releases kallikrein in urine and renin in perfusate. We have previously shown (Kidney Int 24: 58-65, 1983) and confirm here that kallikrein, as well as renin releases are influenced by changes in renal hemodynamics in this model: a rise in perfusion pressure (PP) from 80 to 98 mmHg increases renal perfusate flow (RPF) by 48 +/- 3 p. 100, inhibits renin release and stimulates kallikrein secretion to 234 +/- 84 p. 100 of control values (n = 8). Since the perfusate lacks angiotensinogen, we decided to study the effect on kallikrein of the reconstitution of the renin-angiotensin system in the IPRK by adding angiotensinogen + angiotensin converting enzyme (AG + ACE) to the perfusion medium. After AG + ACE, PP rose to 107 +/- 4 mmHg, RPF decreased by 82 +/- 3 p. 100 as a consequence of the vasoconstrictor effect of angiotensin II, and renin release was suppressed. Again kallikrein secretion was stimulated and increased to 333 +/- 153 p. 100 of control values (n = 4). It is concluded 1) that kallikrein release is influenced by changes in PP but not in RPF on the IPRK. 2) that reconstitution of the renin-angiotensin system by addition of AG + ACE to the perfusate leads to vasoconstriction, suppression of renin release and a marked increase in kallikrein secretion.

Neurophysiological studies on the relation between the structural properties and neurotoxicity of aliphatic hydrocarbon compounds in rats

In order to determine the specific structural properties responsible for neurotoxic activity, the comparative neurotoxicity of n-hexane, methyl n-butyl ketone, 2,5-hexanedione, and their relatives was investigated in the peripheral nerves of rats. The maximum conduction velocity of motor and sensory fibres and the motor distal latency of the tail nerves of rats were periodically examined in animals receiving repeated subcutaneous injections of 11 aliphatic monoketone or diketone compounds and their relatives for prolonged periods. A study of the comparative neurotoxicity of n-hexane, methyl n-butyl ketone, and their metabolites showed that 2,5-hexanedione was the most actively neurotoxic. Furthermore, a study of other symmetrical diketones with different carbon numbers showed that 2,4-pentanedione, which is structurally similar to 2,5-hexanedione, possessed a different type of neurotoxic activity than 2,5-hexanedione. Regarding aliphatic monoketone compounds, acetone, 2-pentanone, 2-heptanone, and 2-octanone were confirmed non-neurotoxic for the peripheral nervous system. Evidence from some previous reports, however, suggested that 3-heptanone, 4-octanone, and 5-nonanone might produce neuropathies by being converted to 2,5-diketones under specific conditions.

A neurophysiological study among Chinese CS2-exposed workers

A neurophysiological study was carried out to examine peripheral neurotoxicity of extremely low levels of CS2, that is, less than 2 ppm (TWA-8hr) among Chinese viscose rayon workers. From the subjects who participated in a 1981 cross-sectional medical survey, 70 male workers exposed to CS2 and age-matched unexposed workers were randomly selected for the present neurophysiological examination. The conduction velocities of motor, sensory and slower motor fibres of the right ulnar nerve were measured using the same methods as those in the study by Seppäläinen (1974). Skin temperature was measured at the middle of the volar surface of the right forearm with a Thermistor thermometer. According to an earlier occupational hygiene survey in the plant, current personal exposures determined by a passive dosimeter method were very low; the average of daily exposure of 7 jobs studied was 1.45 ppm (range 0.2-5.0). Past and current area sampling data also suggested that occupational hygiene conditions regarding CS2 exposure in the plant had been extremely good for the previous 6 years. The present neurophysiological study clearly showed that significant reduction in the conduction velocities of motor and slower motor fibres of the ulnar nerve was detected as a consequence of chronic exposure to low levels of CS2. In the previous cross-sectional medical survey, no retinopathy was found among Chinese workers exposed to CS2 at this level. These results suggested that an effect of CS2 on the peripheral nerve would appear earlier than that on the retina.

Hemoglobin values in adult women of various occupational groups in the community

In 1966 and 1971, the authors studied hemoglobin values of about 2,000 women of 10 different occupational groups and different social classes in the same district. The mean values of hemoglobin and serum iron were highest in nursing students followed by urban housewives and nutritionists and lowest in 3 groups of farm wives and shoe factory laborers. The difference in the mean values of hemoglobin observed among occupational groups was in principle assumed to be due to the difference of frequency in levels of 11-12 g/dl. Hemoglobin levels between 1966 and 1971 tended to improve as a whole and the differences among occupational groups have been reduced. In this study, some kinds of social conditions as well as some physiological factors related to hemoglobin values were investigated. In the same occupational group, unmarried women had a higher level of hemoglobin than married women. Further, married women with infants showed a relatively lower level than those with no infants. This suggests that hemoglobin values of female workers may be significantly influenced not only by work conditions but also by social conditions including family circumstances.

Effects of circulating renin substrate on renal function in isolated perfused rat kidney

The effects of two different amounts of pure rat angiotensinogen were investigated in a closed circuit isolated perfused rat kidney. In response to angiotensinogen, circulating levels of angiotensin I (AI) and angiotensin II (AII) immunoreactive materials were found to increase in a time and dose-dependent manner. Vasoconstrictor and renin inhibitory effects were observed in parallel with the increase in AII. Glomerular filtration rate decreased after administration of angiotensinogen to a greater extent than renal flow and filtration fraction. The characterization by high performance liquid chromatography of peptides generated showed the liberation of AI, des-Asp1AI, AII and des-Asp1AII (AIII). These findings demonstrate that administration of angiotensinogen in an isolated perfused kidney model generates AI and that renal converting enzyme and aminopeptidases are able to convert AI to AII, AI to des-Asp1AI, and des-Asp1AI and/or AII to AIII. Changes in circulating level of angiotensinogen influence the activity of the renin-angiotensin system and, therefore, renal function.

[An electrophysiological study on peripheral neurotoxicity of 2,3-butanedione, 2,4-pentanedione and 2,5-hexanedione in rats]

A series of studies was made to clarify the relationship of the chemical structures of 2,3-butanedione (2,3-BDione), 2,4-pentanedione (2,4-PDione) and 2,5-hexanedione (2,5-HDione) to neurotoxicity in terms of n-hexane neuropathy and relative neurotoxic potentials, using electrophysiological methods. These compounds are all molecularly symmetrical diketones with 4, 5 and 6 carbons respectively. A 200 mg/kg dose of each compound was administered subcutaneously five days a week to one of three groups of eight rats. This program continued for 40 weeks in the case of 2,3-BDione and 2,4-PDione and for 14 weeks in the case of 2,5-HDione. Electrophysiological studies of the effects of the compounds on the peripheral nerve were performed by measuring maximum motor conduction velocities (MCV) and sensory conduction velocities (SCV) in the tail nerve of the rats. Residual latencies (RL), motor distal latencies (DL), amplitudes of the muscle action potentials (MAP), and amplitudes of the nerve action potentials (NAP) were also estimated. A significant slowing of MCV began to be observed in the 2,5-HDione group at the 6th week and in the 2,4-PDione group at 10th week. At 8th week, a significant decrease in SCV was also observed in these two groups. The degree of reduction in both MCV and SCV was more pronounced in the 2,5-HDione group than in the 2,4-PDione group. In the 2,5-HDione group, the MCV values were more strongly affected than the SCV values. On the other hand, in the 2,4-PDione group the SCV values were slowed more than the MCV values. The amplitudes of MAP and NAP in the 2,5-HDione group decreased significantly at 12th week and at 10th week, respectively. In the 2,4-PDione group, a significant decrease in NAP amplitudes was observed at 16th week and that in MAP amplitudes at 28th week. The 2,3-BDione group showed a decrease in MAP amplitudes at 28th week. The RL and DL were markedly prolonged at an early stage only in the 2,5-HDione group. The gamma-diketone of 6, 7 and 8 normal chains of the aliphatic hydrocarbons has been reported to cause peripheral distal axonopathy with giant axonal degeneration. This disorder is named gamma-diketone neuropathy. In this study, neurotoxic evidence was revealed by 2,4-PDione, which is 5-carbon and symmetrical beta-diketone.(ABSTRACT TRUNCATED AT 400 WORDS)

Regulation of kallikrein and renin release by the isolated perfused rat kidney

Rat kidneys perfused in vitro released kallikrein in urine, and renin and kallikrein in the perfusate. The kallikrein was characterized by its kininogenase activity and released bradykinin from bovine and dog substrates. Inactive trypsin activatable kallikrein was present in both perfusate and urine. Kallikrein secretion in urine was influenced by changes in perfusion pressure (PP). Raising the PP strikingly increased urinary kallikrein and lowering PP reduced it. Urinary water and electrolyte output were augmented to the same extent by furosemide and mannitol administration as by raising the PP, but neither drug affected kallikrein. Isoproterenol stimulated the release of renin but not kallikrein. Stopping the oxygen supply to the perfusate suppressed kallikrein secretion in urine and renin release in the perfusate. The kidneys released ten times less kallikrein in the perfusate than in urine, and perfusate kallikrein was not influenced by changes in PP. It is concluded that in this model, changes in PP and/or renal blood flow and/or oxygen supply regulate kallikrein secretion in urine, but that this secretion is unaffected by changes in urinary output. We also conclude that kallikrein release in urine and renin release in perfusate are regulated simultaneously by renal hemodynamic changes but are not affected concomitant by beta-adrenergic stimulation or changes in distal urine composition.

[An experimental study on electrophysiological and histopathological changes in 2,5-hexanedione-intoxicated rats]

An experimental study of neuropathy due to 2,5-hexanedione (2,5-HDione) was performed in rats by using simultaneously both electrophysiological and histopathological methods. Seven rats were given subcutaneously five days a week 200 mg/kg of 2,5-HDione for first 3 weeks and then 300 mg/kg for the next 5 weeks. Nerve conduction velocities in the tail were measured every week and after the respective measurement times one animals was sacrificed for histological study. At the 2nd week of the experiment, 2,5-HDione-treated rat showed a slight morphological changes with swollen axons in the posterior spinal root fiber and tail nerve. A slowing of motor and sensory conduction velocity (MCV and SCV) in the tail was observed in the treated group at the 4th week. Weakness of hindlimbs was apparently seen at the 5th week. At the 6th and 7th week, histological changes including giant axonal swelling, fiber loss, thinning of myelin and demyelination, were prominent in the various regions of the peripheral nervous system. Additionally, degenerative changes of the spermatogenic cells, especially the formation of multinucleated giant spermatids, were markedly observed in the treated rats at the 6th and 7th week.

Vascular effects and metabolism of angiotensins and their metabolites in the isolated perfused rat kidney

The vascular effects of the injection of angiotensin I (AI), des-Asp1-angiotensin I (des-Asp1-AI), angiotensin II (AII), des-Asp1-angiotensin II ( (2-8)AII) and des-Asp1-Arg2-angiotensin II ( (3-8)AII) have been investigated in an isolated perfused rat kidney model, using a closed circuit system. The apparent half-life of these peptides was measured by AI and AII radioimmunoassays. Des-Asp1-AI is less potent than AI and has a shorter duration of action on perfusion pressure and renal flow. Up to 7.6% of circulating AI and 12.4% of circulating des-Asp1-AI are converted by the kidney to AII, (2-8)AII and other AII immunoreactive materials. This intrarenal conversion entirely explains the vasoconstrictor effects of these two peptides. The vasoconstrictor effects of (2-8)AII is similar to that of AII, but (2-8)AII has a shorter duration of action. At the doses injected, renin secretion is completely inhibited by AII and (2-8)AII, it is partially inhibited by AI, an effect which disappears when converting enzyme is inhibited. Des-Asp1-AI is a less potent inhibitor of renin secretion than AI, and (3-8)AII is devoid of any action on renin secretion. The apparent half-life of AI is 24.3 +/- 1.1 minutes, des-Asp1-AI: 20 to 23 minutes, AII: 19.6 +/- 1.8 minutes, (2-8)AII: 12 to 14.5 minutes and (3-8)AII: 12.5 to 13.5 minutes. Differences in the metabolism of these peptides may contribute to the differences of magnitude and duration of their vascular effects.

Diuretic and natriuretic effects of nifedipine on isolated perfused rat kidneys

The effects of nifedipine, a vasodilating drug which acts through calcium antagonism, were studied in vitro using isolated perfused rat kidneys. Most of the nifedipine was neither metabolized nor excreted by this preparation. Four doses were tested: 50, 250, 500 and 750 nM. The two higher concentrations enhanced urine flow and sodium (UNaV) and potassium excretion. Tubular reabsorption of sodium was reduced compared to untreated control kidneys. The glomerular filtration rate was not modified but the filtration fraction decreased. The magnitude of urine volume, UNaV, urinary potassium excretion and filtration fraction changes were related to the dose of nifedipine. The decrement of total renal resistance and the increment of UNaV were correlated for 500 and 750 nM nifedipine (n = 13; r = -0.77; P less than .001), suggesting that it acted by dilating the renal vascular bed. Nifedipine at 250, 500 and 750 nM significantly increased the renin secretion rate compared to that of untreated control kidneys. When renin secretion was enhanced by 50 nM isoproterenol, this stimulatory effect was enhanced in kidneys concomitantly treated with 500 and 750 nM nifedipine. Dihydralazine, another vasodilating drug, was tested at a comparable molar dose (500 nM) and induced similar changes in urine volume, UNaV, urinary potassium excretion and Na reabsorption. The variations in total renal resistance and UNaV were also inversely correlated (n = 8; r = -0.68; P less than .05). Dihydralazine did not modify renin secretion rate significantly. These results suggest that: 1) both nifedipine and dihydralazine increase diuresis, natriuresis and kaliuresis in the isolated perfused rat kidney and 2) nifedipine enhances basal renin release from the juxta-glomerular cells and potentiates renin release caused by beta receptor stimulation.

[An experimental study on the neurotoxicity of 2-octanone and 2-hexanol, a metabolite of n-hexane]

An electrophysiological study of the neurotoxicity of 2-octanone (an analogue of methyl n-butyl ketone) and 2-hexanol (a metabolite of n-hexane) was conducted on rats as a part of the study to determine the specific molecular arrangement required for the development of peripheral neuropathy. The compound 2-octanone or 2-hexanol was administered subcutaneously in the daily dose of 400 mg/kg of each compound into the back of seven rats, weighing 290 g, 5 days per week for a period of 21 weeks. Animals treated with 2-octanone for 21 weeks failed to exhibit apparent clinical and neurophysiological evidence except a slight inhibition of weight gain and narcotic effects after treatment with the compound. The same doses of 2-hexanol for 21 weeks caused hypersalivation, gait disturbances, crossing phenomena of hind limbs and a failure of normal growth. Retardation of the conduction velocity in the motor and sensory nerve fibers and the prolonged motor latencies of the tail nerves (distal part) began to appear at the 14th week of the experiment when 9.6 g in the total dose had been given to each animal. These changes were intensified in the subsequent course of the experiment. Our previous experiments and the present results showed that n-hexane barely produced peripheral neuropathy in doses over 10.5 g, and that 2-hexanone (MBK), 2,5-hexanediol or 2,5-hexanedione never failed to produce a neuropathy even in doses less than 9.6 g of each compound. The above results suggest that the neurotoxic potency of 2-hexanol is greater than that of n-hexane but less than that of MBK, 2,5-hexanediol or 2,5-hexanedione.

Effect of adrenalectomy and aldosterone on the modulation of mineralocorticoid receptors in rat kidney

Adrenalectomized rat kidney is commonly used for the study of mineralocorticoid mechanism of action in mammals. In this model, aldosterone is known to bind to two classes of binding sites: type I (mineralocorticoid) and type II (glucocorticoid). The study of the aldosterone binding in normal rat kidney requires the elimination of endogenous hormones bound to each type of receptor. Thus, a suitable technique was developed using in situ perfusion of the kidneys. The efficacy of this method was of about 85 to 90% at the level of both cytoplasm and nucleus. Aldosterone binding capacity was checked in normal rat kidney after in situ perfusion and was found to be 300 to 500% lower than in adrenalectomized rat kidney, both in cytoplasm and nuclei. Computer analysis of aldosterone binding parameters in the cytoplasm (30,000 X g supernatant) of rat kidney suggested that adrenalectomy might induce an important rise in the number of mineralocorticoid receptors (congruent to 260%). An increase in the number of glucocorticoid receptors was also observed but appeared to be lower. Aldosterone, when perfused during 24 h in adrenalectomized rats, lowered the number of type I sites to the same level as observed in normal rat kidney. This effect was fully reversible after interruption of aldosterone perfusion. These results suggested an aldosterone-induced down regulation of mineralocorticoid receptors.

A comparison of multiple forms of renin in rat renal perfusate with those in renal extract

1. Physicochemical properties of renin secreted by isolated perfused rat kidney were examined and the results compared with those obtained for the renin in renal extract. 2. In renal extract, two high-molecular-weight renins (molecular weight 65 000 and 55 000) and one low-molecular-weight renin (molecular weight 39 000) were found. Their relative proportion varied depending on extraction conditions. By acidification, high-molecular-weight renins were converted into low-molecular-weight renin without marked changes in activity. 3. In renal perfusate only low-molecular-weight renin was found after renin stimulation by isoprenaline or anoxia. Inactive renin was not found. 4. Renin in renal extract and perfusate samples were both found to consist of at least four isoenzymes having different isoelectric points (pI). The pI patterns were identical in renal extract and perfusate samples: pI 5.7 (60-70%), 5.5 (15-25%), 5.3 (5-10%) and 5.0-5.2 (2-5%). 5. These results indicate that the native renin secreted by rat kidney consists entirely of the low-molecular-weight and active form comprising multiple isoenzymes with a stable pI pattern.

[Release of platelet activating factor (P.A.F.-acether) by isolated perfused rat kidney]

Platelet-activating factor (a 1-0-alkyl-2-acetyl glyceryl-3-phosphorylcholine, P.A.F.-acether) causes the aggregation of platelets from various Mammalian species and the release of their granule content. P.A.F.-acether activity has been recovered in vitro from perfused isolated Rat kidneys, stimulated by the ionophore A 23187. The maximum release was reached 10 min. after addition of the ionophore. P.A.F.-acether from kidney exhibited the same physico-chemical and biological characteristics as P.A.F.-acether from leucocytes. These data demonstrate that the kidney secretes a mediator of immediate hypersensitivity (P.A.F.-acether) in the veinous vasculature. Therefore the kidney itself has the ability of inducing intravascular platelet aggregation with subsequent local increase in vasopermeability.

Mechanism of renin inhibition by beta adrenergic blocking agents. Effects of dl-, d-, l-propranolol and pindolol on renin release

In order to reveal the mechanism of renin inhibition by beta adrenergic blocking agents, the effects of dl-, d-, l-propranolol and pindolol on renin release were studied. This was done by injecting them intraperitoneally or by using an in vitro system of rat kidney slices. In the in vivo study, dl-, d-, and l-propranolol inhibited plasma renin activity and renal renin content significantly in normal rats. Furthermore, in the in vitro study, the basal levels of renin in the media and that in the kidney were significantly inhibited by these agents. Pindolol also inhibited renin release, but its effects were significantly less than those of other agents. The finding that d-propranolol which has little beta adrenergic blocking action inhibited renin release, and that the effects of pindolol which displays strong beta adrenergic blocking action but little membrane stabilizing action, were less than those of other agents, may suggest that the inhibitory effects of beta adrenergic blocking agents on renin release are dependent mainly on the membrane stabilizing action rather than the beta adrenergic blocking action.

Effects of converting enzyme inhibitor (SQ 20881) on changes in blood pressure and plasma aldosterone induced by angiotensin I or acute hemorrhage in rabbits

The effects of angiotensin converting enzyme inhibitor (CEI) upon blood pressure and plasma aldosterone (PA) were studied in rabbits with a simultaneous infusion of angiotensin I (ANG I) or with hemorrhagic hypotension. Pretreatment with CEI (SQ 20881), 1.0 mg/Kg, inhibited the effects of infused ANG I, 30 ng/Kg/min, upon PA and blood pressure at 30 min of the infusion, but the inhibition on PA was not significant at 60 min of the infusion. The same dose of CEI was ineffective in blocking the effect of 100 ng/Kg/min of ANG I on PA and blood pressure even at 30 min of the infusion. In rabbits with hemorrhagic hypotension, injection of CEI resulted in the decrement in blood pressure, whereas no decrement in blood pressure was observed in normal control rabbits. This study suggests that CEI exerts it's effect in part by inhibiting conversion of ANG I to angiotensin II (ANG II), but this can't exclude other mechanisms.

Follow-up studies on the distribution of haemoglobin levels in female farm workers

Haemoglobin concentrations in about 1000 women agricultural workers in Japan were measured every year, except in 1972, during the period 1967-77. Improvements were noted in the course of this investigation, and these were predominantly associated with the fact that those in the study community began to pay attention to the problem of low haemoglobin levels and to improve their diet, with an increase in daily food intake, particularly of animal protein and iron. In addition, a marked decrease in anaemia caused by hookworm also played an important role. In this paper, the change in haemoglobin concentration during the period of study are described and the aetiology is discussed.