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S Nakai

Publications and source records attributed to S Nakai.

At least 37 records · Page 2Linked to original sources
PubMed2001

Genetic characterization and evolutionary implications of a car gene cluster in the carbazole degrader Pseudomonas sp. strain CA10.

The nucleotide sequences of the 27,939-bp-long upstream and 9,448-bp-long downstream regions of the carAaAaBaBbCAc(ORF7)Ad genes of carbazole-degrading Pseudomonas sp. strain CA10 were determined. Thirty-two open reading frames (ORFs) were identified, and the car gene cluster was consequently revealed to consist of 10 genes (carAaAaBaBbCAcAdDFE) encoding the enzymes for the three-step conversion of carbazole to anthranilate and the degradation of 2-hydroxypenta-2,4-dienoate. The high identities (68 to 83%) with the enzymes involved in 3-(3-hydroxyphenyl)propionic acid degradation were observed only for CarFE. This observation, together with the fact that two ORFs are inserted between carD and carFE, makes it quite likely that the carFE genes were recruited from another locus. In the 21-kb region upstream from carAa, aromatic-ring-hydroxylating dioxygenase genes (ORF26, ORF27, and ORF28) were found. Inductive expression in carbazole-grown cells and the results of homology searching indicate that these genes encode the anthranilate 1,2-dioxygenase involved in carbazole degradation. Therefore, these ORFs were designated antABC. Four homologous insertion sequences, IS5car1 to IS5car4, were identified in the neighboring regions of car and ant genes. IS5car2 and IS5car3 constituted the putative composite transposon containing antABC. One-ended transposition of IS5car2 together with the 5' portion of antA into the region immediately upstream of carAa had resulted in the formation of IS5car1 and ORF9. In addition to the insertion sequence-dependent recombination, gene duplications and presumed gene fusion were observed. In conclusion, through the above gene rearrangement, the novel genetic structure of the car gene cluster has been constructed. In addition, it was also revealed that the car and ant gene clusters are located on the megaplasmid pCAR1.

Amino Acid Sequence↗
PubMed2001

Increased heat-escape/cold-seeking behavior following hypertonic saline injection in rats.

We examined the effect of hypertonic saline injection on heat-escape/cold-seeking behavior in desalivated rats. Rats were exposed to 40 degrees C heat after normal (154 mM NaCl, control) or hypertonic saline (2,500 mM NaCl) injection (1 ml/100 g body wt). The rats received a 0 degrees C air for 30 s when they entered a specific area in an experimental box. Core temperature (T(c)) surpassed 40 degrees C in both conditions when 0 degrees C air was not available. Hypertonic saline injection produced a lower baseline T(c) than control [36.9 +/- 0.2 and 37.9 +/- 0.2 degrees C (means +/- SE), P < 0.05] and a greater number of 0 degrees C air rewards during the 2-h heat with lower T(c) at the end (48 +/- 1 and 34 +/- 2, 37.6 +/- 0.1, and 37.3 +/- 0.1 degrees C in the control and hypertonic saline injection trial, respectively, P < 0.05, n = 6). However, T(c) was similar (37.7 +/- 0.2 and 37.6 +/- 0.4 degrees C in the control and hypertonic saline injection trial, n = 5) when 0 degrees C air was automatically and intermittently (35 times) given during the heat. Rats augment heat-defense mechanisms in response to osmotic stress by lowering the baseline T(c) and increasing heat-escape/cold-seeking behavior.

Animals↗
PubMed2001

CD31 expression on leukocytes is downregulated in vivo during hemodialysis.

BACKGROUND/AIM: CD31 on leukocytes is the adhesion molecule involved in the leukocyte extravasation in inflammatory conditions. During hemodialysis with cellulosic membranes, it is considered that activated leukocytes adhere to endothelium, but do not show extravasation. However, it is not elucidated why activated leukocytes do not show endothelial transmigration during hemodialysis with cellulosic membranes. METHODS: In the present study, changes in the expressions of Mac-1 and CD31 on granulocytes and monocytes were analyzed by flow cytometry during hemodialysis in 7 patients treated with regenerated-cellulose (RC) membranes and next with polysulfone (PS) membranes. RESULTS: During dialysis with RC, Mac-1 expressions on granulocytes and monocytes both significantly increased as compared with predialysis values and across the dialyzer. During dialysis with RC, the CD31 expression on granulocytes and monocytes significantly decreased as compared with predialysis values. During dialysis with PS, changes in Mac-1 and CD31 expressions on granulocytes and monocytes were smaller than those during dialysis with RC. CONCLUSIONS: Decreased CD31 expression on leukocytes may affect leukocyte function more in patients chronically hemodialyzed with RC than in those hemodialyzed with PS, since CD31 is important in leukocyte transendothelial migration in inflammatory conditions.

Adult↗
PubMed2001

Quantitative estimation of dietary energy deficiency and effects of its supplementation on protein nutritional status of nondiabetic uremic patients undergoing protein restricted dietary regimens.

In chronic renal failure (CRF) patients with a reduced protein intake, if the patients' energy intake could be estimated on the basis of biochemical data together with protein intake, it would be easier to provide them with adequate dietary treatment. Thus, from the relationship among the normalized protein catabolic rate (nPCR) and the intrinsic creatinine generation rate (%GCr) both calculated on the basis of 24-hr urine creatinine, as well as the daily dietary energy intake evaluated by a skilled nutritionist, we devised the following equation to estimate the amount of dietary energy deficiency (delta E) whose supplementation increases the %GCr of patients on protein-restricted dietary regimens to the target level (i.e., the dietary energy deficient amount). This was done by taking the %GCr of average nondiabetic hemodialysis patients of the same age and sex as a temporal target level: delta E = [31.22 - 1.97 (%GCr)0.6]/(nPCR)0.15. In order to examine the clinical usefulness of this equation, the daily dietary energy deficient amount calculated by the equation was supplemented with protein-free jelly. As a result, the %GCr increased from approximately three-fourths of the target level to the target level within 4 months.

Creatinine↗
PubMed2001

[Epidemiological features about serum phosphorus level in renal failure].

Before a renal failure patient begins dialysis therapy, the serum creatinine concentration becomes high and at the same time the serum phosphorus level is also on the rise. In a dialysis patient, on the other hand, the serum phosphorus concentration decreases with age. Also, among those on dialysis, a patient with elevated intact-PTH and one with a high normalized protein catabolic rate (nPCR) show virtually no relation of a high serum phosphorus level with either the serum calcium level or the serum phosphorus level. The phosphorous concentration in a hemodialysis patient is linked to the prognosis, and there is a high mortality risk in a patient with a pre-dialysis serum phosphorus level of less than 3.0 mg/dl or 7.0 mg/dl or more.

English Abstract↗
PubMed2000

Neuronal circuitries involved in thermoregulation.

The body temperature of homeothermic animals is regulated by systems that utilize multiple behavioral and autonomic effector responses. In the last few years, new approaches have brought us new information and new ideas about neuronal interconnections in the thermoregulatory network. Studies utilizing chemical stimulation of the preoptic area revealed both heat loss and production responses are controlled by warm-sensitive neurons. These neurons send excitatory efferent signals for the heat loss and inhibitory efferent signals for the heat production. The warm-sensitive neurons are separated and work independently to control these two opposing responses. Recent electrophysiological analysis have identified some neurons sending axons directly to the spinal cord for thermoregulatory effector control. Included are midbrain reticulospinal neurons for shivering and premotor neurons in the medulla oblongata for skin vasomotor control. As for the afferent side of the thermoregulatory network, the vagus nerve is recently paid much attention, which would convey signals for peripheral infection to the brain and be responsible for the induction of fever. The vagus nerve may also participate in thermoregulation in afebrile conditions, because some substances such as cholecyctokinin and leptin activate the vagus nerve. Although the functional role for this response is still obscure, the vagus may transfer nutritional and/or metabolic signals to the brain, affecting metabolism and body temperature.

Animals↗
PubMed2000

Anorectal and bladder function after sacrifice of the sacral nerves.

STUDY DESIGN: The quantitative changes in anorectal and bladder functions after sacrifice of the sacral nerves were assessed. OBJECTIVES: To evaluate the bladder and anorectal functions before and after sacral nerve division in patients with sacral bone tumors. SUMMARY OF BACKGROUND DATA: The quantitative changes in bladder and anorectal functions after sacrifice of the sacral nerves have not been intensively studied. The purpose of this investigation was to measure the bladder and anorectal function before and after sacral nerve division using manometry and cystometry. METHODS: Surgical resection of a sacral tumor was performed in five patients. The sacral nerves were sacrificed bilaterally in three patients and unilaterally in two patients. Anorectal function was evaluated on the basis of symptoms and physiologic tests. Micturition function was evaluated based on symptoms, and intravesical pressures were measured by cystometry. RESULTS: The two patients with unilateral sacral nerve loss did not experience subjective problems with defecation or micturition, although the residual volume of urine was increased after surgery. Two of the three patients with bilateral sacral nerve loss had no urge to defecate, were unable to differentiate between feces and flatus, and experienced no urgency. Fecal incontinence was uncommon because of firm feces. It was possible to control defecation using enemas on alternate days. The third patient underwent colostomy because the maximum resting pressure, which is controlled by the hypogastric nerves, was affected before surgery. CONCLUSION: Unilateral sacrifice of sacral nerves results in little bladder or anorectal dysfunction.

Adult↗
PubMed2000

Mmh/Ogg1 gene inactivation results in accumulation of 8-hydroxyguanine in mice.

The major mutagenic base lesion in DNA caused by exposure to reactive oxygen species is 8-hydroxyguanine or 7, 8-dihydro-8-oxoguanine (8-OH-G). Products of the human MMH/OGG1 gene are known to catalyze in vitro the reactions repairing this DNA lesion. To analyze the function of Mmh in vivo, we generated a mouse line carrying a mutant Mmh allele by targeted gene disruption. Mmh homozygous mutant mice were found to have a physically normal appearance, but to have lost nicking activity in liver extracts for substrate DNA containing 8-OH-G, exhibiting a 3-fold increased accumulation of this adduct at 9 weeks of age compared with wild-type or heterozygous mice. Further elevation to 7-fold was observed in 14-week-old animals. Substantial increase of spontaneous mutation frequencies was clearly identified in Mmh mutant mice bearing transgenic gpt genes. These results indicate that exposure of DNA to endogenous oxidative species continuously produces the mutagenic adduct 8-OH-G in mice, and Mmh plays an essential role in repair of this DNA damage.

Animals↗
PubMed2000

Experimental study on the dynamics of lumbosacral nerve root circulation.

STUDY DESIGN: Experimental investigation of the dynamics of nerve root circulation. OBJECTIVES: To study the dynamics of lumbosacral nerve root circulation by using seriography in dogs. SUMMARY OF BACKGROUND DATA: The vascular distribution to the nerve root has been discussed mainly from the morphologic aspects, and no adequate elucidation has been presented concerning the kinetics of the blood supply to the nerve root. METHODS: To investigate the direction of blood flow in the nerve roots, a series of photographs of the cauda equina were taken using a motor-driven camera immediately after 3 mL of india ink was injected through the aortic catheter manually. The changes in the blood flow direction caused by compression of the nerve root also were observed. After the dog was killed, the nerve roots were cleared by the Spalteholz technique to identify the vessels observed during the experiment. RESULTS: The blood flow in the radicular arteries was descending in the proximal part and ascending in the distal part of the nerve roots. This observation supports the suggestion that there is a so-called watershed of the blood flow in the radicular arteries themselves. However, when the ascending radicular artery of the nerve root was cramped, the radicular blood flow on the proximal side was downward. The microangiograms also showed that there were abundant anastomoses of intrinsic vessels in the nerve roots. CONCLUSIONS: There is no relatively hypovascular region in the nerve root that is vulnerable in the course of degenerative changes in the lumbosacral spine. Therefore, it is unlikely that the watershed represents a weak point of the blood flow in the nerve root.

Animals↗
PubMed2000

Role of autologous blood transfusion in sacral tumor resection: patient selection and recovery after surgery and blood donation.

We carried out sacral en-bloc resection in six patients (three with chordoma; one with pheochromocytoma; one with malignant schwannoma; and one with giant cell tumor) using preoperatively collected autologous blood, to avoid homologous blood transfusion. An average of 3200 ml was collected preoperatively, with patients receiving recombinant human erythropoietin (r-HuEPO), at a total dose of 130 000 units on average. In four patients, we were able to accomplish the surgery without homologous blood transfusion. Postoperatively, the hemoglobin level in these four patients recovered to the pre-collective level in 4.5 weeks, on average. These clinical results indicate that en-bloc sacrectomy, which requires a large volume of blood transfusion, can be accomplished with preoperatively collected autologous blood alone.

Adrenal Gland Neoplasms↗
PubMed2000

Gender difference in the mean age at the induction of hemodialysis in patients with autosomal dominant polycystic kidney disease.

Male patients with autosomal dominant polycystic kidney disease (ADPKD) begin hemodialysis earlier than female patients. The rate of progression of many other renal diseases is also faster in men than women. In this study, gender difference in ADPKD was compared with that in other diseases, such as chronic glomerulonephritis, diabetic nephropathy, and nephrosclerosis, using the data obtained from an annual statistical survey of the Japanese Society for Dialysis Therapy. The male-female ratio in ADPKD (n = 8,176) was 1.17:1 and closer to 1.0:1 than the other diseases. Men with ADPKD started hemodialysis therapy 1.3 years earlier than women (male age, 55.9 +/- 12.4 years versus female age, 57.2 +/- 11.5 years), and the age difference was less than that in other diseases. These results suggest that the prognosis in women with ADPKD is relatively worse than that in men with ADPKD or that women are not well protected against the progression of this disease compared with other renal diseases. In conclusion, men with ADPKD are introduced to hemodialysis therapy earlier than women; however, the age difference was small compared with other common renal diseases.

Adolescent↗
PubMed2000

Physicochemical changes and mechanism of heat-induced gelation of arrowtooth flounder myosin.

Physicochemical changes of myosin during heating were investigated to elucidate the mechanism of heat-induced gelation of arrowtooth flounder (ATF) myosin at high ionic strength. Changes in dynamic properties indicated ATF myosin formed a gel in three different stages as shown by the first increase in G' (storage modulus) at 28 degrees C, followed by the decrease at 35 degrees C and the second increase at 42 degrees C. DSC thermogram showed the onset of myosin denaturation at 25 degrees C with two maximum transition temperatures at 30 and 36 degrees C. The decrease in alpha-helical content indicated ATF myosin began to unfold at 15 degrees C and the unfolding continued until it reached 65 degrees C. Turbidity measurement showed myosin began to aggregate at 23 degrees C and the aggregation was complete at 40 degrees C. Surface hydrophobicity increased consistently in the temperature range studied, 20-65 degrees C. Sulfhydryl contents decreased significantly at 20-30 degrees C due to the formation of disulfide linkages but remained constant at temperatures >30 degrees C. ATF myosin was shown to be extremely sensitive to heat, resulting in denaturation at lower temperature than other fish myosin. Denaturation was initiated by unfolding of the alpha-helical region in myosin followed by exposure of hydrophobic and sulfhydryl residues, which are subsequently involved in aggregation and gelation processes.

Animals↗
PubMed2000

Solid phase microextraction/gas chromatography of Salmonella-infected beef.

Eight strains of Salmonellae were incubated in TSB culture medium at 37 degrees C for 24 h. Volatile compounds derived from the bacteria were collected using solid-phase microextraction fibers and then applied to gas chromatography (GC). Similarity analysis of the GC patterns thus obtained could separate these strains on principal component similarity (PCS) scattergrams. Five major food-related pathogenic bacteria and 10 other bacteria (including one Salmonella strain) were also classified by growing in the same medium. It is then proposed to utilize this approach to improve the GC/PCS method of Nakai et al. [Nakai, S.; Wang, Z. H.; Dou, J.; Nakamura, S.; Ogawa, M.; Nakai, E.; Vangerstoep, J. J. Agric. Food Chem. 1999, 47, 576-583] that has been developed for screening safe foods by detecting bacteria contaminated foods. Inoculating food samples pre-enriched through preliminary incubation into a culture medium and then subjecting to the GC/PCS method after secondary incubation enhances the detectability of pathogenic bacteria.

Animals↗
PubMed2000

Calbindin-D28k and calretinin in the rat posterior pituitary; light and electron microscopic localization and upregulation with dehydration.

Ca(2+) binding proteins (CaBPs), calbindin-D(28k) (calbindin) and calretinin, are thought to contribute to the regulation of intracellular Ca(2+) in many neuronal populations and perhaps more importantly, signal functional modulation in neuronal activity. In the present experiments, light microscopic immunohistochemistry revealed that the immunoreactivity of calbindin and calretinin was contained in varicose axons in the posterior pituitary. The dual labeling study with confocal microscopy demonstrated that calbindin immunoreactivity was present in the terminals of both oxytocin (OXT) and arginine-vasopressin (AVP) neurons. However, calretinin immunoreactivity was exclusively seen in the OXT terminals. Moreover, the dual labeling study showed that most calretinin-positive terminals contained calbindin immunoreactivity, demonstrating the colocalization of calbindin and calretinin in the same OXT nerve terminals. By electron microscopy, calbindin and calretinin immunoreactivities were seen in the neurosecretory axons and nerve terminals. These immunoreactive nerve terminals were seen to contain more clear microvesicles than dense-core neurosecretory granules. This immunoelectron microscopic observation suggests that both calbindin and calretinin localize preferentially in the active zone of the nerve terminals, which usually face the perivascular space around fenestrated capillaries. In spite of similar localization of calbindin and calretinin within the posterior pituitary, Western blot analysis showed some differences between the two CaBPs. Calbindin was present mostly in the soluble fraction with little in the insoluble fraction, but a substantial portion of calretinin was present in both the insoluble and soluble fractions. Moreover, dehydration induced by drinking 2% NaCl solution and deprivation of drinking water increased calretinin levels in the posterior pituitary as compared with control, but the calbindin level was not changed. The present findings demonstrate that calbindin and calretinin colocalize in the active zones of OXT nerve terminals, but only calretinin is upregulated with dehydration, suggesting different physiological role of calbindin and calretinin in the nerve terminals.

Animals↗
PubMed2000

Anterior transvertebral herniotomy for cervical disk herniation.

This study analyzed the results of anterior transvertebral herniotomy for cervical disk herniation to assess the utility of this procedure. Anterior transvertebral herniotomy was performed in 24 patients who had cervical disk herniation without spinal canal stenosis. In most patients, a good result was obtained, but simultaneous or subsequent anterior intervertebral fusion was necessary in four patients. In one (4%) patient, the two adjacent vertebrae had fused spontaneously. The best indication for this treatment judging from the postoperative results is a large disk hernia associated with either myelopathy or radiculopathy, but without spinal canal stenosis.

Adult↗
PubMed2000

Dose-effect relationship of dicentric and ring chromosomes in lymphocytes of individuals living in the high background radiation areas in China.

Chromosomes of 39 healthy family members (3 generations from 13 families) living both in the high-level background radiation areas (HBRA) and the control areas (CA) were studied. Cumulative dose from birth to the time of blood sampling was estimated by calculating measured exposure rate in each individual. The cumulative doses ranged 30.9-358.9 and 6.0-59.2 mGy for HBRA and CA, respectively. Peripheral lymphocyte chromosome preparations were made according to our improved method. Dicentric and ring chromosomes (Dic + Rc) were scored in average 2,527 cells per individual in HBRA and 2,694 cells in CA under a microscope equipped with an automated stage. A positive correlation between Dic + Rc and age was found in HBRA, while no such dose relationship was clear in CA. The frequency of Dic + Rc linearly increases over lifetime due to chronic low dose exposure and it is likely that the activation of repair enzymes is not triggered in the present HBRA. Threshold dose (rate) of the induction of chromosome aberrations, if any, is below the present dose (rate) level.

Adult↗
PubMed2000

Dose measurement, its distribution and individual external dose assessments of inhabitants in the high background radiation areas in China.

As a part of the China-Japan cooperative research on natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external exposure to natural radiation in the high background radiation areas (HBRA) of Yangjiang in Guangdong province and in the control areas (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all inhabitants directly by personal dosimeters, an indirect method was applied in which the exposed individual doses were estimated from the environmental radiation doses measured by survey meters and the occupancy factors of each hamlet. We analyzed the dose in the hamlets and the variation in the occupancy factors to obtain the parameters of dose estimation on the inhabitants in selected hamlets; Madi and several hamlets of different dose levels in HBRA and Hampizai hamlet in CA. With these parameters, we estimated individual dose rates and compared them with those obtained from direct measurement using dosimeters carried by selected individuals. The results obtained are as follows. 1) The environmental radiation doses are influenced by the natural radioactive nuclide concentrations in building materials, the age of the building and the arrangement of the houses in a hamlet. There existed a fairly large and heterogeneous distribution of indoor and outdoor environmental radiations. The indoor radiation doses were due to exposure from the natural radioactive nuclides in the building materials and were about two times as large as the outdoor radiation doses. The difference between indoor and outdoor doses was not observed in CA. 2) The occupancy factor was influenced by the age of individuals and by the season of the year. The occupancy factor was higher for infants and aged individuals than for other age groups. This lead to higher dose rates of exposure to those age groups. 3) A good correlation was observed between the dose assessed indirectly and that measured directly and the correlation factor was 0.97.

Background Radiation↗