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Biomedical subjects

S Hayami

Publications and source records attributed to S Hayami.

At least 19 recordsLinked to original sources
PubMed2001

Iron(III) spin-crossover compounds with a wide apparent thermal hysteresis around room temperature.

The magnetic properties of the spin-crossover compounds, [Fe(qsal)2]NCSe-MeOH (1) and [Fe(qsal)2]NCSe-CH2Cl2 (2), have been measured. We have discovered that both compounds 1 and 2 exhibit a wide thermal hysteresis loop of 140 K (T(1/2) upward arrow = 352 K and T(1/2) downward arrow = 212 K) and 180 K (T(1/2) upward arrow = 392 K and T(1/2) downward arrow = 212 K), respectively, in the first cycle. Thermogravimetric analysis shows that solvent molecules escape from compounds 1 and 2 around 340 and 395 K, respectively. This means that the hysteresis loops observed for the first cycle are only apparent ones. Following the first loop, they show a two-step spin-crossover in warming mode. The so-called "step 1" and "step 2" are centered around T(1/2(S1)) upward arrow = 215 K and T(1/2(S2)) upward arrow = 282 K, respectively. On the other hand, a one-step spin-crossover occurs at T(1/2) downward arrow = 212 K in cooling mode. The hysteresis widths can be estimated to be 3 K (step 1) and 70 K (step 2), assuming that the widths in steps 1 and 2 are defined as the differences between T(1/2(S1)) upward arrow and T(1/2) downward arrow, and T(1/2(S2)) upward arrow and T(1/2) downward arrow, respectively. The hysteresis width of 70 K in step 2 is one of the widest values reported so far for spin-crossover complexes. It is thought that the cooperativity operating in the complexes arises mainly from the intermolecular pi interactions between quinoline and phenyl rings. Using a previously reported model, we are able to simulate the hysteresis loop with a two-step spin-crossover in warming mode and a one-step transition in cooling mode.

Journal Article↗
PubMed2001

Effectiveness of oxidative potential water as a root canal irrigant.

AIM: The aim of this study was to evaluate the effectiveness of oxidative potential water (OPW) as an irrigant, based on its ability to remove the smear layer and/or debris from instrumented root canals. METHODOLOGY: One hundred and twenty root canals from extracted human maxillary incisors were instrumented using a conventional step-back technique with irrigation from sodium hypochlorite (NaOCl) or oxidative potential water (OPW). After instrumentation, the canals were irrigated by syringe or ultrasound using 15% EDTA or OPW as an irrigant. The volume of each irrigant used for syringe irrigation was 10, 20, and 30 mL, respectively, whilst the duration for ultrasonic irrigation was 1, 3, and 5 min, respectively. After irrigation, each root was split longitudinally in two with cutting pliers, and the specimens were prepared for SEM observation. The presence of debris and smear layer on each canal wall was assessed using a three-point scale for each parameter. RESULTS: Smear layer was effectively removed with EDTA both introduced via syringe and via ultrasonic irrigation. A similar effect was observed with OPW via syringe irrigation following instrumentation with 5% NaOCl. The canal walls in any of these cases showed open and patent dentinal tubules following smear layer removal. Some specimens irrigated with EDTA exhibited the effect of demineralization on the dentine resulting in funnelling of tubule orifices. Syringe irrigation was more effective in smear layer removal, except for ultrasonic irrigation with 15% EDTA, whilst ultrasonic irrigation was more effective in debris removal including the use of OPW as irrigant following instrumentation with 5% NaOCl. Neither syringe nor ultrasonic irrigation with OPW following instrumentation with OPW removed smear layer or debris effectively. CONCLUSIONS: The most effective irrigation technique for smear removal was 15% EDTA irrigation by means of syringe following instrumentation with 5% NaOCl solution. However, the most effective irrigation technique for debris removal was ultrasonic irrigation regardless of irrigant used. OPW irrigation by means of syringe following instrumentation with 5% NaOCl showed a similar effect to that of 15% EDTA irrigation for removal of smear layer and debris.

Anti-Infective Agents, Local↗
PubMed2001

Voiding dysfunction in a patient with adolescent adrenoleukodystrophy.

The details are reported of bladder dysfunction in a Japanese boy with adrenoleukodystrophy. He developed gait disturbance at the age of 15 years. Spastic paraparesis progressed from the legs to the hands and brain magnetic resonance imaging showed characteristic degenerative change. Detrusor hyperreflexia was found by a urodynamic study and detrusor-sphincter dyssynergia was also suspected.

Adolescent↗
PubMed2000

Change in caspase-3-like protease in the liver and plasma during rat liver regeneration following partial hepatectomy.

Recent studies have shown that many factors orchestrate liver regeneration after a two-thirds partial hepatectomy (PH). However, the termination mechanism in liver regeneration has not been thoroughly studied. In this paper, we report that the activity of liver caspase-3-like protease, which is specifically activated in apoptosis, increases 18, 36, and 48 hr after PH during maximal hepatocyte proliferative activity. This is the first study that shows the activation of an apoptosis-executing enzyme during physiological liver regeneration. These results suggest that apoptosis is induced in each surge of DNA synthesis as the termination mechanism. When phenoxybenzamine, an alpha-blocker that has been reported to inhibit DNA synthesis during liver regeneration, was injected 8 hr after PH, the caspase-3-like activity in the liver peaked at 15 hr after PH and the enzyme activity also increased in plasma at 18 and 24 hr after PH in sharp contrast to the case of normal regeneration. These results indicate that extensive apoptosis is caused by phenoxybenzamine and that the secondary necrosis of apoptotic cells results in the increase of caspase-3-like protease activity in the plasma.

Animals↗
PubMed2000

Evaluation of oxidative stress based on lipid hydroperoxide, vitamin C and vitamin E during apoptosis and necrosis caused by thioacetamide in rat liver.

After 12 h of thioacetamide (500 mg/kg body weight) administration to rats, the activity of caspase-3-like protease in the liver increased significantly compared to that in the control group. In plasma, the activity of caspase-3 was barely detectable in the control rat, but had increased significantly after 24 h of drug administration along with a dramatic increase in GOT. These results indicate that thioacetamide causes apoptosis in the liver by activating caspase-3, which is released to plasma by successive necrosis. At 24 h, the concentration of liver lipid hydroperoxides, a mediator of radical reaction, was 2.2 times as high as that of control rats. After 12 and 24 h of thioacetamide administration, the liver concentrations of vitamins C and E decreased significantly. The decrease of antioxidants and formation of lipid hydroperoxides 24 h after thioacetamide administration support the view that extensive radical reactions occur in the liver during the necrotic process.

Animals↗
PubMed2000

In vivo antioxidative activity of propolis evaluated by the interaction with vitamins C and E and the level of lipid hydroperoxides in rats.

In vivo antioxidative activity of propolis was evaluated on the basis of ameliorative effects on the oxidative stress induced by vitamin E deficiency in rats. The control group was fed vitamin E-deficient diet, and the propolis group was fed vitamin E-deficient diet supplemented with 1% of propolis for 4 and 8 weeks. Comparisons were made in tissue concentrations of vitamin C, vitamin E, and lipid hydroperoxides between these groups. No significant difference was observed in tissue vitamin E concentration between these groups after both 4 and 8 weeks. After 4 weeks, the plasma vitamin C concentration of the propolis group was significantly higher than that of the control group. After 8 weeks, the tissue concentrations of vitamin C in the kidney, stomach, small intestine, and large intestine of the propolis group were significantly higher than those of the control group. These results suggest that some components of propolis are absorbed to circulate in the blood and behave as a hydrophilic antioxidant that saves vitamin C. The concentration of lipid hydroperoxides in the large intestine of the propolis group was significantly lower than that of the control group after 8 weeks. These results suggest that propolis exerts its antioxidative effect where it is assumed to accumulate, such as on the kidney, where it is excreted, and on the gastrointestinal tract, where propolis influences these tissues even from the outside of the cell.

Animals↗
PubMed1999

Increase of caspase-3 activity in rat liver and plasma by thioacetamide.

Twelve and twenty-four hours after intraperitoneal administration of thioacetamide (200 mg/kg body weight) to rats, caspase-3 activity in the liver and plasma of the treated rats increased significantly compared with that of the control group. These results demonstrated that thioacetamide caused apoptosis, which involved activation of caspase-3, although there may be a number of pathways to apoptosis in the liver that may or may not involve the activation of this protein. The results also indicated that the activated caspase-3 was released in plasma along with glutamate-oxaloacetate transaminase (GOT) by successive necrosis. This is the first study that shows an increase of caspase-3 activity in plasma.

Animals↗
PubMed1999

Canal configuration of the mesiobuccal root of the maxillary first molar of a Japanese sub-population.

AIM: The aim of this study was to determine the percentage of anatomical canal configurations of the mesiobuccal root of the maxillary first molar in Japanese patients. METHODOLOGY: Three hundred teeth were obtained from general dentists who knew absolutely that they were extracted from Japanese patients. The distobuccal and palatal roots were amputated for radiographic convenience. Preoperative radiographs were taken of the remaining crown and mesiobuccal root (MBR) from mesiodistal and buccopalatal directions for each tooth. Routine endodontic access cavities were prepared and size 08 files were placed through the orifice into the MBR until they were seen at the apex. In some cases preparation of the canal orifice with a long shank round burr was necessary to gain access. In seven teeth, no access to the apex was possible and these teeth were eliminated. In the other 293 teeth, the MBR canal(s) was (were) enlarged up to size 15 file. If another canal opening was found at the apex a 08 file was inserted into the second opening and passed coronally. Postoperative radiographs with file(s) in place were taken from the two directions, as before. RESULTS: Of the 293 teeth, 123 (42.0%) were Type II, 89 (30.4%) showed Type III systems and 10 (3.4%) were Type IV. Suggestions for identification and treatment of the second canal in the MBR are presented. CONCLUSIONS: The proportion of cases with two canals in the mesiobuccal root of maxillary first molars from Japanese patients was high and similar to that described from studies of other ethnic populations.

Asian People↗
PubMed1998

The effect of triathlon on urinary excretion of enzymes and proteins.

In order to investigate the effect of triathlon and renal function of normal subjects, we evaluated the excretion of urinary enzymes and proteins before and after triathlon. From 6 subjects samples were obtained 24 hours after the first urine collection. We performed quantification of urinary total protein, beta2-microglobulin (beta2-M), N-acetyl-beta-D-glucosaminidase activity (NAG), and concentration of urinary creatinine from each participant. There was a significant increase in urinary total protein excretion immediately after triathlon (p<0.01). The urinary beta2-M and NAG excretions after triathlon were higher than the initial values. Post-exercise proteinuria in one subject persisted until the next morning, whereas the increased excretion of urinary beta2-M and NAG returned to the pre-exercise level at least 24 hours after triathlon. It appears to be reasonable to presume that glomerular damage may persist in some subjects who do heavy exercise.

Acetylglucosaminidase↗
PubMed1998

Juxtaglomerular cell tumor without hypertension.

Juxtaglomerular cell tumors are rare. This report presents a case of juxtaglomerular cell tumor without hypertension. All previously reported cases showed marked hypertension, whereas this is the first case of juxtaglomerular cell tumor without hypertension. The immunohistochemistry and ultrastructure of this case are discussed.

Adenocarcinoma↗
PubMed1998

Serum levels of total and free prostate specific antigen in men on hemodialysis.

PURPOSE: The measurement of prostate specific antigen (PSA) is widely used in screening programs for early detection of prostate cancer. It has been recently shown that the ratio of free-to-total PSA in serum is lower in malignant than in nonmalignant prostatic disorders and, therefore, might be a parameter to improve screening specificity. We determine the influence of renal failure on serum levels of total and free PSA, and free-to-total PSA ratio. MATERIALS AND METHODS: Serum concentrations of total and free PSA, and free-to-total PSA ratio were measured in 93 men undergoing hemodialysis. The control group consisted of 2,298 healthy blood donors. RESULTS: Serum levels of total PSA were not significantly different between control and hemodialysis patients. Serum free PSA and free-to-total PSA ratio of hemodialysis patients were significantly higher than those of controls (p <0.01 to 0.001). However, these values did not change in uremic patients after hemodialysis. Although serum total and free PSA levels increased with each decade of age, they did not correlate with age in hemodialysis patients. CONCLUSIONS: Serum free PSA as well as total PSA is not eliminated by hemodialysis, and elevated levels of free PSA and free-to-total PSA ratio in hemodialysis patients may be caused by a concomitant decrease in binding proteins. The reference ranges for total and free PSA, and free-to-total PSA ratio may not be necessarily beneficial in hemodialysis patients.

Adult↗
PubMed1997

Effect of the alpha-1 adrenoceptor blocker on tissue norepinephrine contents in human benign prostatic hyperplasia.

To see the effect of the alpha-adrenergic blocking agent on tissue norepinephrine contents of the prostate, norepinephrine (NE) levels were investigated in patients with symptomatic benign prostatic hyperplasia (BPH). Morphometrical analyses were also performed to detect the differences in tissue composition. Nineteen patients were subdivided into two groups. Patients in Group 1 were given tamsulosin hydrochloride (0.2 mg/day) for at least 4 weeks before transurethral resection of the prostate (TURP), while patients in the control group (Group 2) underwent no previous treatment for BPH before TURP. Tissue NE contents were investigated by high performance liquid chromatography on a chip of the prostate obtained by TURP. These two groups were closely similar in age distribution, prostatic size, results of preoperative symptom scoring and relative proportion of smooth muscle component within the evaluated specimen. In the present series, tissue NE contents in these groups were not statistically different (p = 0.64). Chronic and acute administration of the alpha-1 antagonist did not apparently influence the tissue NE level in patients with BPH.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed1997

A case of primary giant calculus in female urethra.

Urinary calculus is rarely seen in the urethra and is usually encountered in men with urethral stricture or diverticulum. Primary urethral calculi are extremely rare in females. We describe a case of a giant urethral stone impacted in the urethra of a 103-year-old female.

Aged↗
PubMed1997

Thermoreceptor mediated bladder sensation in patients with diabetic cystopathy.

Urinary bladder sensation to ice water instillation was evaluated in 32 patients with diabetes mellitus. Sixteen patients were urodynamically normal (group 1) and the remaining 16 were diagnosed as having diabetic cystopathy (group 2). Eleven out of 16 patients in group 2 could be considered as having impairment of sensation to urinate. Two out of 16 (12.5%) subjects in group 1 could not perceive ice water infusion, whereas 25% of patients in group 2 did not feel the ice water sensation. In group 2, patients with impaired urinary sensation showed relatively high incidence of negative ice water test (36.4%), although there were no statistical differences between the other groups. There was no apparent relationship between prevalence of peripheral neuropathy and that of negative ice water test. Impairment of ice water perception was less frequent than that of mechanoreceptor sensation in patients with diabetic cystopathy.

Aged↗
PubMed1997

Histopathological study of a newly developed root canal sealer containing tetracalcium-dicalcium phosphates and 1.0% chondroitin sulfate.

We studied the possibility of the clinical use of a calcium phosphate-type newly developed sealer composed of tetracalcium phosphate, dicalcium phosphate dihydrate, and a modified McIlvain's buffer solution (TDM). Another sealer using the buffer solution, to which 2.5% chondroitin sulfate was added to promote wound healing (TDM-S), was also studied. TDM and TDM-S were histopathologically compared with another type of calcium phosphate sealer (ARS), which is commercially available in Japan, in the dorsal subcutaneous tissue and in the periapical tissue of rats. TDM and TDM-S caused no inflammatory reactions in the subcutaneous tissue. The periapical tissue reacted mildly to them. ARS caused severe inflammatory reactions in both the subcutaneous and the periapical tissue. These results indicate that TDM-S has excellent histocompatibility and potential as a root canal sealer.

Acrylic Resins↗