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Biomedical subjects

T Shono

Publications and source records attributed to T Shono.

At least 91 records · Page 5Linked to original sources
PubMed1995

Acquired Chiari I malformation and syringomyelia associated with bilateral chronic subdural hematoma. Case report.

The authors report a case of bilateral chronic subdural hematoma in a 25-year-old woman who had occipital and neck pain. Magnetic resonance imaging revealed progressive caudal descent of the cerebellar tonsils (acquired Chiari I malformation) and a large eccentric syrinx in the spinal cord from the C3-T7 levels. Spontaneous disappearance of the chronic subdural hematomas resulted in radiographic resolution of both lesions, as well as clinical improvement. Theories of syringomyelia formation, the relationship to acquired Chiari I malformation, and the implications of this case are discussed.

Adult↗
PubMed1995

The progressive degeneration of interlobular bile ducts in biliary atresia: an ultrastructural study.

The ultrastructure of the interlobular bile ducts were observed in hepatic specimens obtained at surgery in ten patients with biliary atresia, in order to investigate the progress of their degeneration over time after the onset of the disease. As an index for the passage of time, the degree of fibrosis in the portal tracts was investigated. Then the ultrastructural features in the interlobular bile ducts were contrasted with the grading of portal fibrosis Generally, the ultrastructural changes of the interlobular bile ducts were more marked in the cases with severe portal fibrosis than that observed in the cases with mild fibrosis. This correlation suggests that the degeneration of the interlobular bile ducts progressively worsens over time after the obliteration of the extrahepatic bile duct.

Bile Ducts, Extrahepatic↗
PubMed1994

The effect of flutamide on testicular descent in rats examined by scanning electron microscopy.

The effect of prenatal flutamide exposure on testicular descent was investigated by using scanning electron microscopy (SEM) in prenatal and postnatal rats. In 20-day-old fetal rats, SEM showed no significant difference in the degree of gubernacular development or testicular descent relative to the kidney between flutamide-treated (74.5 +/- 2.2 U) and control rats (73.3 +/- 1.5 U); however, there was significant inhibition in oestrogen-treated rats (44.3 +/- 2.2 U) (P < .001). (The distance between the kidney and the bladder neck was standardized to 100 U.) In 5-day-old rats, SEM showed inhibited downward growth of the processus vaginalis in flutamide-treated rats. The length of processus vaginalis below the inguinal ligament was 32.8 +/- 2.4 U in flutamide-treated rats and 51.7 +/- 1.8 U in controls (P < .001). In 30- to 35-day-old mature rats, the frequency of cryptorchidism was 41.3% for flutamide-treated rats and 0% for controls (P < .001). Some cryptorchid testes were located in the lower abdominal cavity (10.9%); others were in the suprainguinal position (26.1%) or on the line of descent in the inguinal region (4.3%). In the flutamide-treated group, no testes were located in the posterior abdominal cavity, near the kidney. These results suggest that transabdominal descent of the testis is independent of androgen action, but that androgens control inguinoscrotal descent of the testis by regulating gubernacular migration and the growth of the processus vaginalis.

Animals↗
PubMed1994

Relationship between surface area for adhesion and tensile bond strength--evaluation of a micro-tensile bond test.

OBJECTIVES: The purpose of this study was to test the null hypothesis that there is no relationship between the bonded surface area of dentin and the tensile strength of adhesive materials. METHODS: The enamel was removed from the occlusal surface of extracted human third molars, and the entire flat surface was covered with resin composite bonded to the dentin to form a flat resin composite crown. Twenty-four hours later, the bonded specimens were sectioned parallel to the long axis of the tooth into 10-20 thin sections whose upper part was composed of resin composite with the lower half being dentin. These small sections were trimmed using a high speed diamond bur into an hourglass shape with the narrowest portion at the bonded interface. Surface area was varied by altering the specimen thickness and width. Tensile bond strength was measured using custom-made grips in a universal testing machine. RESULTS: Tensile bond strength was inversely related to bonded surface area. At surface areas below 0.4 mm2, the tensile bond strengths were about 55 MPa for Clearfil Liner Bond 2 (Kuraray Co., Ltd.), 38 MPa for Scotchbond MP (3M Dental Products), and 20 MPa for Vitremer (3M Dental Products). At these small surface areas all of the bond failures were adhesive in nature. SIGNIFICANCE: This new method permits measurement of high bond strengths without cohesive failure of dentin. It also permits multiple measurements to be made within a single tooth.

Composite Resins↗
PubMed1994

Capsaicin increases the frequency of cryptorchidism in flutamide-treated rats.

Capsaicin, a specific neurotoxin that irreversibly results in degeneration of sensory C fibers of the peripheral nerves, was investigated for its ability to affect testicular descent. In particular, we investigated the ability of prenatal flutamide, postnatal capsaicin or combined prenatal flutamide with postnatal capsaicin to induce undescended testes in rats. Within these treatment groups the frequency of maldescent was 42% in the animals treated prenatally with flutamide, 32% with postnatal capsaicin, and 100% with prenatal flutamide and postnatal capsaicin. Of interest, it was found that all animals that received capsaicin had maldevelopment of the scrotum. Our data suggest that capsaicin increased the frequency of cryptorchidism in rats prenatally treated with flutamide, perhaps by inhibition of scrotal development. These findings indicate that sensory nerves to the scrotum may affect scrotal development and testicular descent.

Animals↗
PubMed1994

Transabdominal testicular descent is really ovarian ascent.

Some investigators have suggested that testicular descent relative to the ovary is actually caused by the relative upward growth of the structures adjacent to the testis and that in the early phase of descent the testis is anchored to the inguinal region as the embryo enlarges. This concept was founded on results from the dissection of human fetuses. In this study the development of the urogenital system in fetal mice is examined using scanning electron microscopy to determine the distance between the bladder neck and the lower pole of the gonad. The results of this study confirm that transabdominal descent of the testis relative to the ovary is in one sense really ascent of the ovary in the fetal mouse, while the testis is anchored to the inguinal region by the developed gubernaculum. The testis shows real movement at the beginning of the inguinoscrotal phase of testicular descent at birth.

Animals↗
PubMed1993

Postoperative MRI evaluation of anorectal malformations with clinical correlation.

Sixteen postoperative patients with anorectal malformation were evaluated by MRI, and the results compared with the clinical assessment. Patients were classified into three groups--good (group 1, n = 10), fair (group 2, n = 3) and poor (group 3, n = 3)--on the basis of Kelly's clinical score of incontinence. The degree of development of the puborectalis and external sphincter muscles and the levator hammock was evaluated on MRI in comparison with patients without anorectal disease. The proportions of fair or poor development of the muscles were 37% in group 1,22% in group 2 and 67% in group 3. Although fair or poor development of the muscles was seen more frequently in group 3, there was no statistically significant difference between groups. However, poorly developed muscles were seen only in patients with fair or poor clinical scores. The difference in the anorectal angle measured on sagittal MRI images between patients in group 1 and groups 2 or 3 was significant. Our study indicates that MRI evaluation based solely on muscle development can be misleading, and measurement of the anorectal angle should be included in the MRI evaluation.

Abnormalities, Multiple↗
PubMed1993

Motility function of the esophagus before primary anastomosis in esophageal atresia.

Two patients with a long gap esophageal atresia without tracheoesophageal fistula underwent an esophageal manometric study before primary anastomosis and one of them underwent an identical study after operation. Before operation both patients showed peristaltic contraction in the proximal esophagus when swallowing which was always followed by a coordinated contraction of the distal esophagus the same as in that of the normal esophagus. These peristaltic contractions induced a reflex relaxation of the lower esophageal sphincter (LES). After operation the manometric studies of the repaired esophagus demonstrated an abnormal esophageal motility, with simultaneous contractions occurring when swallowing in the proximal to the distal esophagus. In addition, the reflex relaxation of LES was incomplete. These data suggest that even if the intraluminal continuity is defective, the esophageal motility function is not disturbed in the proximal to distal esophagus in preoperative esophageal atresia, and that intraoperative mobilization and denervation may be suggested to be an important factor in esophageal dysmotility even when esophageal atresia is successfully repaired.

Anastomosis, Surgical↗
PubMed1993

[Cardiorespiratory responses during flume swimming and treadmill running in swimmers].

The present study was designed to compare cardiorespiratory responses of swimmers to swimming and running. Six male trained college swimmers performed maximal work test (progressive method) in flume swimming and treadmill running. VEmax during swimming (128.3 +/- 20.6 l/min) was about 4% lower than during running (133.2 +/- 9.9 l/min). VO2max during swimming (3628 +/- 228 ml/min) was significantly higher than during running (3408 +/- 222 ml/min). HRmax during swimming (191 +/- 8 beats/min) was significantly lower than during running (198 +/- 6 beats/min). VO2 at ventilatory threshold (VT) during swimming (2177 +/- 183 ml/min) was significantly higher than during running (1699 +/- 214 ml/min). %VO2max at VT during swimming (60.1 +/- 4.2%) was significantly about 10% higher than during running (49.8 +/- 4.4%). These results suggest that subjects of this study have specific cardiorespiratory adaptation to swimming from a long period of swim training.

Adult↗
PubMed1993

Effect of aging on dentin bonding.

The purpose of this paper was to evaluate the effect of aging of dentin on the tensile bond strengths of four dentin bonding systems using proximal dentin of premolars extracted from young (aged from 9-21 years) and old (aged from 42-64 years) patients. Clearfil Linerbond System and Super Bond D-Liner showed higher bond strengths to both young and old teeth than those of Clearfil Photo Bond and Resto Bond 3. However, similar bond strengths to both young and old teeth for all four products were obtained despite the effects of aging. Furthermore, a SEM study of the site of bond failure revealed the persistence of the resin impregnated layer on the dentin surface, in spite of the difference of bonding system and dentin, indicating that adhesive failure tended to occur at the interface between the bonding resin and the resin impregnated layer.

Adolescent↗
PubMed1992

Comparison of the conversion rates of alpha-linolenic acid (18:3(n - 3)) and stearidonic acid (18:4(n - 3)) to longer polyunsaturated fatty acids in rats.

The delta 6-desaturase reaction is regarded to be the rate-limiting step in the conversion of linoleic acid (18:2(n - 6)) to arachidonic acid (20:4(n - 6)). The same is probably also the case with the conversion of alpha-linolenic acid (18:3(n - 3)) to eicosapentaenoic acid (20:5(n - 3)). However, there are very few in vivo studies that directly compared the conversion rate between 18:3(n - 3) and stearidonic acid (18:4(n - 3)), which is the delta 6-desaturated product of 18:3(n - 3). We compared this rate by feeding rats on a lipid-free diet supplemented with lard (9%, w/w) and 18:3(n - 3) ethyl ester (1%) diet or on a diet containing lard (9%) and 18:4(n - 3) ethyl ester (1%). A lard (10%)-supplemented diet was used as the control diet. The fatty acid compositions of total phospholipids, triglycerides and free fatty acids of both liver and plasma were measured after 1 or 3 weeks on different diets. The molar ratio of 20:5(n - 3) of most lipid fractions was about 2-fold higher in rats fed the 18:4(n - 3)-supplemented diet than in rats fed the 18:3(n - 3)-supplemented diet. 18:4(n - 3) was found in the liver lipid fraction in only a very small amount, even in the 18:4(n - 3)-supplemented groups. Thus, desaturation at C-6 is suggested to be the rate-limiting step in the conversion of 18:3(n - 3) to 20:5(n - 3).

Animals↗
PubMed1992

Right-sided diaphragmatic hernia following group B streptococcal pneumonia and sepsis.

A case of right-sided diaphragmatic hernia following group B streptococcal pneumonia and sepsis is reported herein. The clinical course was characteristic. The position of the right hemidiaphragm was initially normal. After an antecedent group B streptococcal infection, an abnormal shadow indicating either pneumonia or a pleural effusion on the chest x-ray was recognized and an elevation of the bowel and liver into the right hemithorax gradually appeared. Repair of the hernia was indicated and the postoperative result was excellent. The relationship between a delayed-onset diaphragmatic hernia and a group B streptococcal infection is still unknown. Increased intrathoracic pressure caused by mechanical ventilation coupled with an abnormal lung compliance due to inflammation may have resulted in the delayed herniation. Among various methods for diagnosis applied, chest x-ray and ultrasonography were noninvasive and useful.

Hernia, Diaphragmatic↗
PubMed1992

Manometric evaluation of gastrointestinal motility in a case of megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS).

We report on a manometric study of the esophagus, stomach, duodenum, jejunum and anorectum in a case of megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS). An esophageal examination showed normal esophageal contractions and a positive rectoanal reflex was obtained in an anorectal manometry. However, the continuous fasting manometric recording of the antrum, duodenum and jejunum lasting a total of 12 hours revealed a severe motility disturbance of the gastrointestinal tract. During the examination a band of low amplitude contractions was observed in the antrum only once and it was followed by small rhythmic contractions of the duodenum, but none of propagated or spontaneous contractions were seen in the jejunum.

Child, Preschool↗
PubMed1990

Flow injection of lithium ion using chromogenic 14-crown-4 derivatives as extraction-spectrophotometric reagents.

A system for flow injection of Li+ has been designed, with use of proton-dissociable chromogenic 14-crown-4 derivatives as the extraction-spectrophotometric reagents, and the analytical conditions have been optimised. This flow injection system showed high selectivity for Li+ reflecting the cation-complexing property of the chromogenic crown ethers. The determination of Li+ in the clinical range in blood under a high Na+ background of 130-160 mM was feasible, with a small sample size (50 microliters) and high sampling rate (more than 100 injections per hour), with this method. The proposed extraction-spectrophotometric flow injection system was, therefore, found to be promising for the efficient determination of Li+ in biological samples, such as blood sera, with a high Na+ background.

Autoanalysis↗
PubMed1990

Autosomal sex-associated pyrethroid resistance in a strain of house fly (Diptera: Muscidae) with a male-determining factor on chromosome three.

Mechanisms and genetics of resistance to pyrethroid insecticides were investigated in a strain of house fly (ASPR) collected from a cattle ranch in Miyagi, Gunma Prefecture, Japan. Flies were selected in the laboratory with the pyrethroid insecticide permethrin. Both sexes were resistant to pyrethroids; however, females were 22- to 245-fold more resistant than males. Permethrin resistance could be partly suppressed by the monooxygenase inhibitor piperonyl butoxide in females, but not in males. In this strain, sex was determined by a male factor on the third autosome. The relationship of the autosomal male factor to the lower resistance levels observed in the males and the mechanisms of resistance expressed in each sex are discussed.

Animals↗
PubMed1990

Effect of magnesium deficiency on lipid metabolism in uremic rats.

The effects of acute magnesium deficiency on lipid metabolism were examined in five-sixths nephrectomized uremic rats and sham-operated rats. Three weeks after the surgery, both groups were divided into two subgroups. Half of the uremic and sham-operated rats received a magnesium-deficient diet. The rest of the experimental animals received a control diet. After 2 weeks on this regimen, all animals were sacrificed. In uremic rats, magnesium deficiency increased serum triglyceride levels and decreased high-density lipoprotein cholesterol levels as in sham-operated rats. Total serum cholesterol levels were higher in uremic rats than in sham-operated rats with or without magnesium deficiency. Serum free fatty acid levels were increased only in uremic rats with magnesium deficiency. These results suggest that magnesium deficiency worsens several parameters of lipid in uremic rats.

Animals↗
PubMed1989

New ultraviolet labelling agents for high-performance liquid chromatographic determination of monocarboxylic acids.

New UV-labelling agents have been synthesized, which are designed to convert monocarboxylic acids into their highly UV-absorbing derivatives for enhancement of the sensitivities of UV detection in high-performance liquid chromatography. The reagents are p-nitrobenzyl, 3,5-dinitrobenzyl and 2-(phthalimino)ethyl p-toluenesulphonates. Each has been prepared by reaction of p-toluenesulphonyl chloride with p-nitrobenzyl alcohol, 3,5-dinitrobenzyl alcohol or N-(hydroxyethyl)phtalimide, respectively, in the presence of sodium hydroxide, and they are stable in the solid state for at least 6 months. Monocarboxylic acids were derivatized to their p-nitrobenzyl, 3,5-dinitrobenzyl or 2-(phthalimino)ethyl esters with each of the above reagents, respectively, then determined by high-performance liquid chromatography with UV detection. In the UV-labelling with each reagent, 18-crown-6 was used as the catalyst. The effects of the reaction solvent, reaction temperature and time and the concentrations of each reagent and the catalyst were also examined.

Carboxylic Acids↗