PubMed Health⌕ Search

Biomedical subjects

Kunio Kobayashi

Publications and source records attributed to Kunio Kobayashi.

16 recordsLinked to original sources
PubMed2006

Diagnosis of the "large medial meniscus" of the knee on MR imaging.

Although several quantitative magnetic resonance (MR) diagnostic criteria for discoid lateral meniscus (DLM) have been described, there are no criteria by which to estimate the size of the medial meniscus. We define a medial meniscus that exceeds the normal size as a "large medial meniscus" (LMM), and the purpose of this study is to establish the quantitative MR diagnostic criteria for LMM. The MR imaging findings of 96 knees with arthroscopically confirmed intact semilunar lateral meniscus (SLM), 18 knees with intact DLM, 105 knees with intact semilunar medial meniscus (SMM) and 4 knees with torn LMM were analyzed. The following three quantitative parameters were measured: (a) meniscal width (MW): the minimum MW on the coronal slice; (b) ratio of the meniscus to the tibia (RMT): the ratio of minimum MW to maximum tibial width on the coronal slice; (c) continuity of the anterior and posterior horns (CAPH): the number of consecutive 5-mm-thick sagittal slices showing continuity between the anterior horn and the posterior horn of the meniscus on sagittal slices. Using logistic discriminant analysis between intact SLM and DLM groups and using descriptive statistics of intact SLM and SMM groups, the cutoff values used to discriminate LMM from SMM were calculated by MW and RMT. Moreover, the efficacy of these cutoff values and three slices of the cutoff values for CAPH were estimated in the medial meniscus group. "MW> or =11 mm" and "RMT> or =15%" were determined to be effective diagnostic criteria for LMM, while three of four cases in the torn LMM group were true positives and specificity was 99% in both criteria. When "CAPH> or =3 slices" was used as a criterion, three of four torn LMM cases were true positives and specificity was 93%.

Adolescent↗
PubMed2006

Comparison of response to 17 beta-estradiol and 17 beta-trenbolone among three small fish species.

Three small fish species, medaka (Oryzias latipes), fathead minnow (Pimephales promelas), and zebrafish (Danio rerio), were exposed to an estrogen, 17 beta-estradiol (E2), and an androgen, 17 beta-trenbolone (TB), for 21 d under flow-through conditions to compare the susceptibility among these three small fish species to the substances. Effects on gross morphology, including secondary sex characteristics and gonadosomatic index, as well as on blood or liver vitellogenin (VTG) levels were assessed. In E2 exposures, significant increases in estrogenic activity were observed in both sexes of all three fish species. The lowest-observed-effect concentrations (LOECs) of E2 for VTG induction in males of medaka, fathead minnow, and zebrafish were less than or equal to 8.94, 28.6, and 85.9 ng/L, respectively. In TB exposures, we observed masculinization of secondary sex characteristics in females as a result of the androgenic activity of TB in medaka with a LOEC of 365 ng/L and in fathead minnow with a LOEC of 401 ng/ L. We also found VTG reduction in females of all three fish species. These results suggest that the susceptibility of medaka to estrogenic chemicals may be higher than those of fathead minnow and zebrafish and that the susceptibility of medaka to androgenic chemicals may be almost equal to that of fathead minnow in the 21-d fish assay.

Animals↗
PubMed2005

Prognostic implications of inhalation injury in burn patients in Tokyo.

Inhalation injury has recently emerged as the major cause of mortality in burn patients. However, the prognostic value of inhalation injury has not been thoroughly assessed in Japanese burn facilities. The aim of the present study was to evaluate the impact of inhalation injury on burn patients' mortality in Tokyo. Of 6416 patients admitted to 13 burn facilities of the Tokyo Burn Unit Association between 1984 and 2002; the 5560 eligible patients were included in this study (mean age, 40+/-20 years; male, 61.6%; mean partial- and full-thickness burn size, 10.7+/-13.0% and 9.6+/-20.5%). Of the 5560 patients, 1690 patients (30.4%) had experienced inhalation injury. The overall in-hospital mortality rate of the patients with inhalation injury was higher than that of those without inhalation injury (33.6% versus 8.1%, odds ratio, 5.72 [95% CI, 4.91-6.67]). The results of the multivariate analysis indicated that inhalation injury; full- and partial-thickness burn size, and age were independent predictors of outcome (relative risk, 2.58 [2.03-3.29], 1.10 [1.09-1.11], 1.06 [1.06-1.07], 1.05 [1.05-1.06], respectively). In conclusion, inhalation injury was the most important predictor of overall mortality among burned patients in Tokyo.

Adult↗
PubMed2005

Fish full life-cycle testing for 17beta-estradiol on medaka (Oryzias latipes).

We studied the chronic effects of 17beta-estradiol (E2) on the reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure to assess its hazard on this species. The exposure of parental (F0) medaka to E2 was begun on embryos within 12 h postfertilization and continued for up to 101 d; the assessment endpoints included embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to E2 at each mean measured concentration of 0.939, 2.86, 8.66, 27.9, and 92.4 ng/L. Eggs (F1) spawned from the F0 fish at 98, 99, and 100 d posthatch were also examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG level until 59 d posthatch. In the F0 medaka, no concentration-related effect of E2 was observed on hatching, posthatch mortality, and growth. However, we observed abnormal sex differentiation, induction of VTG, and reproductive impairment in a dose-dependent manner. The lowest-observed-effect concentration and no-observed-effect concentration of E2 for these effects were 8.66 and 2.86 ng/L, respectively. In the F1 medaka treated with E2 at < or = 8.66 ng/L, however, dose-dependent effects were not observed in any parameter. The results indicate that E2 can have significant effects on reproductive potential of medaka at concentrations as low as 8.66 ng/L, suggesting that the ecological risk of E2 is higher than that of weak estrogens, such as nonylphenol and octylphenol.

Animals↗
PubMed2004

Fish full life-cycle testing for androgen methyltestosterone on medaka (Oryzias latipes).

Abstract-We studied the chronic effects of methyltestosterone (MT) on reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure to verify the applicability of the fish full life-cycle test (FFLC) for this androgen with this species. The exposure of parental (F0) medaka to MT was begun on embryos within 12 h postfertilization and continued for up to 101 d; assessment endpoints included embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to MT at each mean measured concentration of 0.35, 1.09, 3.29, 9.98, and 27.75 ng/L. Eggs (F1) spawned from the F0 fish at 98, 99, and 100 d posthatch were examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG level until 60 d posthatch. In the FFLC with medaka, MT induced masculinization of both secondary sex characteristics and gonads. We observed that all F0 fish in the 27.75-ng/L treatment group showed male secondary sex characteristics in which no fish with ovary could be discerned. Several fish with ovaries in F0 and F1 generations treated with 9.98 ng/L showed male secondary sex characteristics. We also observed swollen abdomens in the F0 and F1 female fish in the 9.98-ng/L treatment group. These swollen abdomens were induced by enlarged ovaries and were accompanied with declined fecundity and fertility in the F0 generation. These results indicate that MT reduces the reproductive potential of medaka and that the FFLC with this species is applicable to the evaluation of androgens.

Animals↗
PubMed2004

[Suppression of neutrophil immune function in rabbit models of hemorrhagic shock complicated by intra-abdominal hypertension].

OBJECTIVE: To investigate the effects of hemorrhagic shock and intra-abdominal hypertension (IAH) on inflammatory responses of peripheral circulating neutrophils such as intracellular cytokine production, phagocytic capacity and expression of nuclear factor (NF)- kappaB. METHODS: Twenty-four rabbits were divided equally into 4 groups including a hemorrhagic shock (HS) group complicated by abdominal compartment syndrome (ACS) (Group A), a HS group (Group B), a ACS group (Group C) and a normal control group (Group D). Intracellular interleukin (IL)-8 production in the peripheral neutrophils were measured in the rabbits by flow cytometry, phagocytic function of the neutrophils evaluated by a chemiluminescence method and the NF-kappaB expression detected by immunocytochemistry before, immediately and 4 h after the traumatization. RESULTS: Four hours after the trauma, decreased intracellular IL-8 production and impaired phagocytic function of the peripheral neutrophils were observed in Group A along with suppressed NF-kappaB expression. But in Group B and Group C, the intracellular IL-8 production, phagocytic function and expression of NF-kappaB returned to the normal levels 4 hours after the trauma following the early-stage changes. In Group D, no significant changes occurred during the observation. CONCLUSIONS: Responsiveness and function of the neutrophils to the stimuli by endotoxin are suppressed by the sequential second-hit of IAH after hemorrhagic shock, which may contribute to the occurrence of sepsis in ACS.

Abdomen↗
PubMed2004

Development of vitellogenin assay for endocrine disrupters using medaka (Oryzias latipes).

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of the egg yolk precursor vitellogenin (VTG) in the liver of medaka (Oryzias latipes) and was employed to establish an in vivo testing system for estrogen and estrogenic compounds using liver homogenates. Results of 3-month-old fish exposed to three reference chemicals (ethynylestradiol, methyltestosterone and flutamide) recommended by Organisation for Economic Co-operation and Development (OECD) for the validation showed the induction and decrease of vitellogenic responses, making the assay using the liver VTG of medaka a possible screening method for not only estrogens but also androgens. In addition, 21-day exposure of male fish to 4-tert-octylphenol and 4-nonylphenol produced concentration-dependent inductions of liver vitellogenin, with the lowest observed effect concentrations of 64.1 microg/L and 22.5 microg/L, respectively, while no significant VTG responses were observed in male and female fish exposed to tributyltin chloride and dibutyl phthalate. This study demonstrates that the VTG assay using liver homogenates from small fish such as medaka can be used as a screening method for environmental estrogens. This is because the sensitivity of the VTG response in medaka may be almost the same as that of other fish using blood samples.

Androgens↗
PubMed2003

Biliary cystadenocarcinoma followed up as benign cystadenoma for 10 years.

We describe a case of biliary cystadenocarcinoma that showed a longterm clinical course. A 69-year-old Japanese man was admitted to our hospital because of abdominal discomfort. The patient had been diagnosed with benign cystadenoma of the liver at another hospital in 1987 and had been followed up for 10 years. Abdominal ultrasonography (US) and computed tomography (CT) scan demonstrated a unilocular cystic lesion, which included multiple conspicuous papillary protrusions in the left hepatic lobe. Left lateral segmentectomy was performed, and intraoperative cholangiography revealed a communication between the cystic tumor and intrahepatic bile duct. The tumor contained clear mucinous fluid and enfolded multiple yellowish papillary projections on the cystic wall. Histological examination showed the tumor to be biliary cystadenocarcinoma. The patient is doing well 4 years after the operation.

Abdomen↗
PubMed2003

[Postgraduate trauma education for surgeon--from the veiwpoint of trauma and emergency physicians].

A recent important topic in the field of trauma care is the elimination of "preventable death." Since patients' satisfactory prognosis and good recovery mainly depend upon the success of the initial evaluation and care, the responsibility of physicians who first come into contact with trauma patients in the emergency room is especially heavy. Many general surgeons examine trauma patients, although, unfortunately they have few opportunities for training in how to deal with those patients in the present educational program. Traumatology should be one of the most important areas of surgery, and therefore this paper emphasizes that every surgeon needs to be educated and trained in an adequate curriculum of trauma care. The Japanese Association for Acute Medicine could help by offering the Japan Advanced Trauma Evaluation and Care (JATEC) training program. JATEC proposes standardized guidelines as well as a nationwide the educational program for trauma management.

Education, Medical, Graduate↗
PubMed2003

Fish full life-cycle testing for the weak estrogen 4-tert-pentylphenol on medaka (Oryzias latipes).

We studied the chronic effects of 4-tert-pentylphenol (4-PP) on reproductive status of medaka (Oryzias latipes) over two generations under continuous exposure, with the goal of verifying the applicability of the fish full life-cycle test (FFLC) for this weak estrogen with this species. The exposure of parental (F0) medaka to 4-PP was begun on embryos within 12 h after fertilization and continued for up to 101 d, with monitoring of embryological development, hatching, posthatch survival, growth, sexual differentiation, reproduction, and hepatic vitellogenin (VTG) levels under flow-through exposure to 4-PP at mean measured concentrations of 51.1, 100, 224, 402, and 931 microg/L. Eggs (F1) spawned from the F0 fish at 99, 100, and 101 d after hatch also were examined for hatchability, survival after hatching, growth, sexual differentiation, and hepatic VTG levels, until 61 d after hatch. In the FFLC with the F0 medaka, the lowest-observed-effect concentration (LOEC) of 4-PP for lethal and sublethal toxicity (as shown by growth inhibition) was 931 microg/L. The LOECs for estrogenic effects (as shown by abnormal sexual differentiation and VTG induction) were 224 and < or = 51.1 microg/L, respectively, and the LOEC for reproductive impairment was 224 microg/L. Therefore, the effective concentrations of 4-PP for abnormal sexual differentiation and reproductive impairment were about four times lower than those for lethal and sublethal toxicity. In the F1 medaka, the LOECs for sublethal toxicity and estrogenic effects were 224 and < or = 51.1 microg/L, respectively. This finding suggests that the continuous exposure to 4-PP over two generations induced these adverse effects at lower concentrations in the F1 generation than those in the F0 generation. Thus, 4-PP has estrogenic effects that reduce the reproductive potential of medaka. The results indicate that the FFLC with medaka is applicable to the evaluation of weak estrogens.

Animals↗
PubMed2003

Effects of 4-nonylphenol and 4-tert-octylphenol on sex differentiation and vitellogenin induction in medaka (Oryzias latipes).

Medaka (Oryzias latipes) were continuously exposed to various concentrations of two alkylphenols, 4-nonylphenol (NP) and 4-tert-octylphenol (OP), from fertilized eggs to 60 d posthatch. The effects on sexual differentiation and hepatic vitellogenin (VTG) induction in medaka were assessed to elucidate the lowest-observed-effect concentrations (LOECs) of NP and OP for these events during early life stages. The LOECs of NP and OP for these events were 11.6 and 11.4 microg/L, respectively. These results suggest that NP and OP may have adverse effects at similar concentrations during early life stage in medaka. Additionally, we investigated whether the abnormal sex differentiation induced by these alkylphenols would be permanent or reversible once the medaka were returned to clean water. The appearance of the secondary sex characteristics reverted from female to male when fish were returned to clean water. However, gonadal histology showed that intersex gonads still existed, even after the fish were transferred to clean water for two months. These results suggest that the induced feminization of secondary sex characteristics in medaka exposed to alkylphenols during the stage of sexual differentiation may not always be permanent, but the gonadal alteration (testis-ova) may continue much longer.

Animals↗
PubMed2002

Diagnosis of discoid lateral meniscus of the knee on MR imaging.

To establish the quantitative MR diagnostic criteria for discoid lateral meniscus, MR imaging of 60 knees with arthroscopically confirmed discoid lateral menisci and 134 knees with semilunar lateral menisci were analyzed. Following four quantitative parameters were measured. (1) Meniscal width (MW): The minimum meniscal width on the coronal slice. (2) Ratio of the meniscus to the tibia (RMT): The ratio of minimum meniscal width to maximum tibial width on the coronal slice. (3) Percent coverage of the meniscus (PCM): The ratio of the sum of the width of the anterior and posterior horns to the meniscal diameter on the sagittal slice showing the maximum meniscal diameter. (4) Continuity of the anterior and posterior horns (CAPH): The number of consecutive sagittal slices showing continuity between the anterior and posterior horns of the meniscus on the sagittal slice. The cut-off values of each parameter to discriminate between the discoid and semilunar meniscus were calculated based on a univariate logistic regression analysis. The sensitivity and specificity were also calculated for each of 4 parameters and combinations of these parameters. The cut-off value was 15 mm for the MW, 20% for the RMT, 75% for the PCM, and 3 slices for the CAPH. The sensitivity and specificity of the four parameters ranged between 87% and 50% and between 99% and 92%, respectively. The most accurate diagnostic criterion was either the RMT > or = 20% or the PCM > or = 75%, and the sensitivity and specificity were 95% and 97%, respectively, even when torn menisci were included.

Adolescent↗
PubMed2002

[Damage control surgery--a historical view].

"Damage control surgery" is a surgical strategy to cope with the lethal triad of death, i.e., acidosis, hypothermia, and coagulopathy, often seen in severely injured patients. Perihepatic packing was attempted by some trauma surgeons during the 1970s as an alternative to hepatectomy for severe liver injury, with favorable results. The concept of bail-out surgery and reoperation was introduced during the 1980s as a treatment modality for severe abdominal trauma. This strategy of trauma care was named "damage control surgery" by Rotondo et al in 1993, which consists of initial laparotomy, secondary resuscitation, and definitive surgery. Angiography and TAE may be used during secondary resuscitation for hemostasis. The concept of damage control surgery is now applied not only to severely injured patients but also for other surgical patients in critical condition. Damage control surgery was introduced to Japan during the late 1990s. However, the Japanese experience has been limited because the volume of severe trauma cases is very small.

Critical Care↗
PubMed2002

Effect of ethinylestradiol on the reproduction and induction of vitellogenin and testis-ova in medaka (Oryzias latipes).

Mature medaka (Oryzias latipes) were exposed to ethinylestradiol (EE2) at measured concentrations of 32.6, 63.9, 116, 261, and 488 ng/L for 21 d under flow-through conditions. Effects on reproductive success of the fish as well as on gonadal condition and vitellogenin (VTG) induction were assessed. A significant decrease in fecundity was observed only at the highest EE2 concentration, whereas hepatic VTG concentration in males was increased at concentrations of 63.9 ng/L and greater. In addition, an intersex condition (testis-ova) of the gonad was observed in male medaka exposed to EE2 concentrations of > or = 63.9 ng/L. Overall, these results indicate that the lowest-observed-effect concentrations of EE2 based on reproduction versus induction of both VTG and testis-ova in the medaka were 488 and 63.9 ng/L, respectively. Thus, the physiological and histological measurements were approximately eightfold more responsive to the EE2 exposure than were overt reproductive effects. This suggests that the elevated VTG levels and testis-ova may not be definitely responsible for reproductive impairment of the fish.

Animals↗