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Biomedical subjects

H Kuroki

Publications and source records attributed to H Kuroki.

At least 19 recordsLinked to original sources
PubMed2006

Maturation-dependent change and regional variations in acoustic stiffness of rabbit articular cartilage: an examination of the superficial collagen-rich zone of cartilage.

OBJECTIVE: The purpose of the study was to investigate maturation-dependent changes of acoustic (ultrasound) stiffness and other ultrasound features of articular cartilage in healthy rabbit knees. METHODS: Five groups of rabbits of various ages (3 weeks, 8 weeks, 6 months, 1 year, 2.5 years) consisting of five rabbits per group were examined. Signal intensity (index of stiffness), signal duration (index of surface irregularity) and interval between signals (index of thickness) of the ultrasound reflection from articular cartilage were examined at four sites: posterior lateral femoral condyle, posterior medial femoral condyle, lateral tibial plateau, and medial tibial plateau. The sites were observed macroscopically and microscopically with a light microscope and a polarized light microscope. RESULTS: At the lateral and medial condyles and the lateral tibial plateau, signal intensity was least in 3-week-old specimens. The intensity increased until 6 months or 1 year of age. At these sites, the signal durations and intervals between signals were least at the ages of 6 months or 1 year. At the medial tibial plateau, the intensity was the least at 2.5 years of age and the interval between signals was least at 3 weeks of age; there was no effect of age on signal duration. Cartilage surfaces of all specimens were smooth and no degenerative changes were macroscopically or microscopically evident. The surface brightness of cartilage under the polarized light microscope was consistent with signal intensity values. CONCLUSIONS: The response of articular cartilage to ultrasound was maturation-dependent. Acoustic properties differed from mechanical stiffness properties, which were determined using indentation. Ultrasound may detect properties of the surface collagen of the articular cartilage.

Aging↗
PubMed2001

Gene analysis of Vibrio cholerae NAGV14 pilus and its distribution.

Adhesive pilus of Vibrio cholerae 034, strain NAGV14, was genetically analyzed. The deduced amino acid (aa) sequence of the major pilin structural gene (VcfA) was 67% homologous to the MshA pilin in the N-terminal region, but no homology was found in the C-terminal region which contained the antigenic epitopes. Upstream and downstream flanking regions examined were highly homologous to mshB and mshC of the MSHA (mannose-sensitive hemagglutinin) gene locus. A short leader sequence and a pair of cysteines near the C-terminus which are the characteristics of type 4a pilus family were found. The major pilin structural gene of NAGV14 was compared to that of a strain V10 producing non-adhesive pili. The deduced aa sequences showed 60% homology, and the distance between two cysteines in the C-terminal region was different. A total of 177 V. cholerae strains were investigated for the presence of a type 4 pilus gene locus by PCR, and 95% were positive. The major pilin gene of NAGV14 was detected in 4 of 93 V. cholerae non-O1, non-0139 strains tested, but none of the V. cholerae O1 and O139 (72 and 12 strains, respectively). Our result suggested that a type 4 pilus gene locus similar to the MSHA gene locus is widely distributed among V. cholerae strains. We proposed naming this type 4 pilus gene locus the VCF (for V. cholerae flexible pili) gene locus.

Amino Acid Sequence↗
PubMed2001

Pesticide poisoning initially suspected as a natural death.

A pesticide poisoning victim suspected initially as having died a natural death was autopsied. The victim was a 47-year-old male. Macroscopically, signs of acute death and, in particular, general erosion in the mucosa of the airways and esophagus were observed. In the gastric contents, which had a pungent smell and a greenish-brown color, 5.00 g/L of propanil, 1.27 g/L of carbaryl, 0.38 g/L of ethylbenzene, and 0.32 g/L of xylene were detected. In the blood (serum), 21.6 mg/L of propanil, 8.1 mg/L of carbaryl, 1.7 mg/L of ethylbenzene, and 4.0 mg/L of xylene were identified. Postmortem methemoglobinemia (45%) was recognized. The cause of death was considered to have been pesticide poisoning; propanil was probably most responsible for his death. The police considered the case to be "death with illness as the suspected cause." By performing an autopsy, however, we were able to clarify that the cause of death was pesticide poisoning.

Carbaryl↗
PubMed2001

The effects of subminimal inhibitory concentrations of beta-lactam antibiotics against Clostridium perfringens.

The effects of subminimal inhibitory concentrations (sub-MIC) of four beta-lactam antibiotics [penicillin-G (PCG), ampicillin (AMP), cephaloridine (CER), cephalothin (CET)] were tested against Clostridium perfringens type A PB6K, after determining the minimum inhibitory concentrations (MIC) of 29 different Clostridium strains. The majority of the strains were sensitive to all beta-lactam antibiotics. Morphological changes, such as filamentous development and lysis, occurred at concentrations considerably lower than the MIC of CER and CET in C. perfringens. Clear cooperation of AMP and CER with rabbit polymorphonuclear leucocytes (PMNL) against C. perfringens was observed. The filamentous bacteria produced as a result of exposure to sub-MIC of each antibiotic, were phagocytosed easily. The ratios between the drug concentrations (microg/ml) at which the morphological changes began to occur, the minimum antibiotic concentrations (MAC), and the MIC values (microg/ml), were calculated. A large ratio indicated a wide range of effective concentrations below the MIC value for the antibiotics.

Animals↗
PubMed2001

[The changes of PCBs and PCDFs as well as symptoms in Yusho patients for 30 years].

Two mass-food poisonings called Yusho and Yucheng occurred in Western Japan and Taiwan in 1968 and 1979, respectively. Blood samples from 5 Yusho patients and 3 Yucheng patients were collected several times from 1982 to 1998 and from 1980 to 1995, respectively, and analyzed for PCB and PCDF congeners. Fat base concentrations of 2,3,4,7,8-penta-CDF in the Yusho patients, which were responsible for about 70% of the dioxin toxicity, are estimated to be decreased from 60 ppb in 1969 to 0.8 ppb in 1997 with the median half-life of 2.9 years in the first 15 years after the onset and 7.7 years in the next stage of 15 years. Fat base concentrations of total PCBs in the blood of Yusho patients are estimated to be decreased from 75 ppm just after the onset to 2.3 ppm after passage of 30 years. Typical Yusho symptoms of acneiform eruption, dermal pigmentation and increased eye discharge were very gradually recovered with lapse of ten years. However, enzyme and/or hormone mediated sign of high serum triglyceride, high serum thyroxin, immunoglobulin disorder and others are persistently maintained for 30 years.

Acneiform Eruptions↗
PubMed2001

[Assessment of hydroxylated metabolites of polychlorinated biphenyls and polychlorinated dibenzofurans as potential estrogens by yeast two-hybrid system].

The estrogenic activities of several hydroxylated metabolites of PCBs and PCDFs were investigated by yeast two-hybrid assay based on the ligand-dependent interaction of estrogen receptor with coactivator. For the hydroxylated PCBs, the order of estrogenic potency was 4-OH-2',4',6'-triCB > 4-OH-4'-monoCB, 4-OH-biphenyl. These compounds were evaluated as 10(3) to 10(4) less potent than 17 beta-estradiol based on the concentrations of test compounds showing 10% activity of 10(-7) M 17 beta-estradiol. 2-OH-3',4,4'-triCB, 4-OH-2',3,4'-triCB and 3-OH-/4-OH-2,2',5,5'-tetraCB, the metabolites of 2,2',5,5'-tetraCB were inactive as estrogens at the highest concentrations used in this study (10(-5) M). Also 4-OH-3,3',4',5-tetraCB, the metabolite of 3,3',4,4'-tetraCB was inactive as estrogen, indicating that this hydroxylated metabolite did not take part in the estrogenic activity of 3,3',4,4'-tetraCB. OH group at 4-position of biphenyl was necessary for the expression of estrogenicity, but one or two chloro-substitution adjacent to OH group inhibited the activity. For the hydroxylated PCDFs, 8-OH-2-monoCDF, 7-OH-3,4-diCDF, 8-OH-3,4-diCDF, 8-OH-3,4,6-triCDF and 3,8-(OH)2-2-monoCDF exhibited estrogenic activity. The estrogenic activity of 3,8-(OH)2-2-monoCDF was comparable to those of 4-OH-2',4',6'-triCB and 4-nonylphenol (mixture of compounds with branched sidechain). The order of activity was 3,8-(OH)2-monoCDF > 8-OH-3,4-diCDF, 7-OH-3,4-diCDF > 8-OH-2-monoCDF, 8-OH-3,4,6-triCDF. These compounds were evaluated as 2.5 x 10(3) to 3 x 10(4) less potent than 17 beta-estradiol. On the other hand, no estrogenic activity was observed for 2-OH-dibenzofuran, 3-OH-2,8-diCDF, 6-OH-3,4-diCDF and 9-OH-3,4-diCDF at concentrations as high as 10(-4) M. Substitution of OH group at 2(8)- or 3(7)-position of dibenzofuran and no chloro-substitution adjacent to OH group was required for the estrogenic activity.

Animals↗
PubMed2001

[Causes of dementia and bed-ridden state in elderly victims of road traffic accidents in Japan].

BACKGROUND: In Japan, autopsies are seldom performed for the victims of road traffic accidents (RTA). Thus, when an elderly RTA victim dies after long-term hospitalization, the actual cause of death is hard to determine. SUBJECTS: Eight hundred eleven road traffic victims (69 +/- 16 years, M/F = 592/219) for whom insurance companies required us to judge the medical causal relation between the accident and the death from the view point of clinical forensic medicine. METHODS: We discussed and reevaluated the cause of death and decided the cause and effect relation based on medical information. RESULTS: The number of subjects was equivalent to 8.4% of the yearly deaths by RTA in the investigated area, 19.3% of the aged death by RTA. An autopsy was performed only for 5%, ISS was 17.0 +/- 11.5; 94% were hospitalized; 62% continued to be unconscious, involving dementia (32%), persistent vegetative state (17%), coma or semi-coma (13%). Of the cases investigated, 89% died after becoming bedridden, which in 87% of cases was due to the RTA. The odds ratios of a bedridden state for head AIS > = 3, lower limbs AIS > = 2, lower limbs AIS > = 3, spinal AIS > = 3, chest AIS > = 2 were 3.1, 3.2, 7.2, 2.5, 1.8, respectively. The odds ratios of dementia for head AIS > = 3, head AIS > = 4, chest AIS > = 4 were 29.2, 35.9, 1.2, respectively. Patients with head injuries were more likely to be bedridden and senile, and patients with leg fractures tended to be bedridden, particular in the aged. When elderly traffic victims became bedridden or senile, most of them, 399 bedridden victims and 53 non-bedridden victims, died within 242 +/- 283 days, and 356 +/- 284 days from the RTA, respectively. The cause of death could be classified into five categories; pneumonia, other infection, malnutrition and/or dehydration, malnutrition and/or dehydration with pneumonia, malnutrition and/or dehydration with other infection. Traffic deaths were recorded on 31% of death certificates, but were 77% by our reevaluation (p < 0.00001), because the cause-of-death can be difficult to determine in elderly traffic victims. Logistic regression was used to calculate the risk of dementia caused by bone fractures after adjusting for age and gender. The risk of dementia due to bone fractures was influenced by the number of the long fractured bones, a high age group, a lower ADL, and a past history of dementia. Thus, we speculate that traumatic dementia based on bone fractures may occur.

Accidents, Traffic↗
PubMed2000

Haemophilus influenzae infection and Guillain-Barré syndrome.

It has been reported recently that Haemophilus influenzae can elicit an axonal form of Guillain-Barré syndrome. To investigate the incidence and features of H. influenzae-related Guillain-Barré syndrome, anti-H. influenzae antibody titres were measured by enzyme-linked immunosorbent assay (ELISA) in 46 consecutive Japanese patients with Guillain-Barré syndrome, 49 normal controls, 24 patients with multiple sclerosis and 27 patients with amyotrophic lateral sclerosis (ALS). Whole bacteria of non-encapsulated (non-typable) H. influenzae isolated from one of the Guillain-Barré syndrome patients was the antigen used. Elevated anti-H. influenzae antibodies for two or three classes of IgG, IgM and IgA were found in six (13%) Guillain-Barré syndrome patients, but not in the normal controls and patients with multiple sclerosis or ALS. The incidence was significantly higher in patients with Guillain-Barré syndrome than in the normal controls (P = 0.01) and patients with multiple sclerosis or ALS (P = 0.009). Western blot analysis confirmed that the H. influenzae-positive patients' IgG recognized the lipopolysaccharides of H. influenzae. Guillain-Barré syndrome patients with anti-H. influenzae antibodies showed relatively uniform clinical and laboratory features: prodromal respiratory infection, less frequent cranial and sensory nerve involvement, pure motor axonal degeneration on electrophysiology, and positivity for IgG anti-GM1 antibodies. Although the features were similar to those in Guillain-Barré syndrome patients infected by Campylobacter jejuni, the recoveries seemed to be better in patients with H. influenzae-related Guillain-Barré syndrome. It is concluded that a form of Guillain-Barré syndrome occurs after respiratory infection by H. influenzae in the Japanese population. A particular strain of non-typable H. influenzae has a ganglioside GM1-like structure and elicits axonal Guillain-Barré syndrome similar to C. jejuni-related Guillain-Barré syndrome.

Adult↗
PubMed2000

Characterization of an early decline in baseline plasma glucose concentration after acute insulin elevation during euglycemic hyperinsulinemic clamp in patients with type 2 diabetes mellitus.

To investigate the contribution of the liver to whole-body insulin resistance in patients with type 2 diabetes mellitus, we analyzed the early decline (slope "a") in the baseline plasma glucose level following acute hyperinsulinemia in the initial phase of a euglycemic hyperinsulinemic clamp study, rather than using an isotope-dilution method. Slope "a" was comparable among groups of diabetic and non-diabetic subjects, and did not correlate well with glucose infusion rate (GIR), an index of peripheral (primarily skeletal muscle) insulin resistance. In contrast, slope "a" was significantly lower in obese (BMI > 25) type 2 diabetic patients compared with their non-obese counterparts, consistent with the general belief that obesity is a condition of insulin resistance in liver as well as in peripheral tissues. A subset of six insulin-resistant (nearly zero GIR) type 2 diabetic patients (pubertal adolescents) demonstrated a markedly blunted slope "a". Their insulin resistance (GIR) substantially recovered concomitant with an increase in slope "a" after pretreatment with somatostatin analogue in two cases studied, suggesting possible suppression of hepatic glucose production through lowering of plasma glucagon concentrations. Furthermore, slope "a" correlated significantly (r = -0.480, p<0.0001) with HOMA index (FPG x FIRI), the latter being recently regarded as an index of hepatic insulin resistance. These data showed that slope "a" obtained from euglycemic hyperinsulinemic clamp may be a clinically useful index of hepatic insulin resistance rather than an index of peripheral insulin resistance.

Adolescent↗
PubMed2000

[Infections with drug resistant bacteria and their treatment methods--PRSP infections].

S. pneumoniae is one of the most important pathogens in respiratory tract infections and systemic infections. The frequencies of isolating Penicillin-resistant Streptococcus pneumoniae(PRSP) has been increasing recently. The therapeutic strategy is becoming difficult. Ampicillin and amoxicillin are the choices of drugs to treat respiratory infections with intermediate strains. Panipenem may be the first choice of treatment for systemic infections. Administration of vancomycin should also be considered. Judicious use of antimicrobials is necessary to avoid the spread of multi-resistant strains. In some cases physical therapy would be recommended.

Child, Preschool↗
PubMed1999

Haemophilus influenzae has a GM1 ganglioside-like structure and elicits Guillain-Barré syndrome.

The authors report a patient with an axonal Guillain-Barré syndrome (acute motor axonal neuropathy) associated with anti-GM1 antibody after Haemophilus influenzae infection. The result of ELISA inhibition studies and cytochemical staining with cholera toxin suggest the presence of a GM1-like structure on the surface of H. influenzae isolated from the patient. A particular strain of H. influenzae may have a GM1-like structure and may elicit an axonal Guillain-Barré syndrome.

Adult↗
PubMed1999

A comparative study of chemonucleolysis with recombinant human cathepsin L and chymopapain. A radiologic, histologic, and immunohistochemical assessment.

STUDY DESIGN: Investigation of the effects of recombinant human cathepsin L on intervertebral discs and comparison with the effects of chymopapain. OBJECTIVE: To evaluate the effects of cathepsin L on intervertebral discs as an agent for chemonucleolysis. SUMMARY BACKGROUND DATA: Cathepsin L is a typical cysteine proteinase that belongs to the papain superfamily. It plays a major role in intracellular proteolysis and is not believed to induce anaphylactic reactions. METHODS: In vivo: Rabbit intervertebral discs were injected with recombinant human cathepsin L, its buffer solution, and chymopapain. After 1, 4, and 16 weeks the animals were killed, and radiologic and histologic examinations were performed. In vitro: The enzymatic actions of recombinant human cathepsin L and chymopapain on human intervertebral disc proteoglycans were examined immunohistochemically using antiproteoglycan antibodies. RESULTS: In rabbit models, roentgenography showed that disc spaces treated with cathepsin L and chymopapain had become narrower 1 week after injection. Histologically, loss of safranin-O staining was observed in the anulus fibrosus of discs treated with cathepsin L. After 16 weeks, nucleus pulposus had regenerated with chondrocyte-like cells, and the safranin-O staining characteristics of the matrix also had recovered. In an immunohistochemical study, all components of the proteoglycan stained weakly after chymopapain digestion. After cathepsin L digestion, unsulfated chondroitin and core protein staining was weaker, but the chondroitin 6-sulfate staining was unaffected. CONCLUSIONS: Cathepsin L seems to be an effective agent for chemonucleolysis. Its enzymatic action on proteoglycan appears to be different from that of chymopapain.

Adult↗
PubMed1999

Detection of influenza virus RNA by reverse transcription-PCR and proinflammatory cytokines in influenza-virus-associated encephalopathy.

Eleven children with acute encephalopathy associated with an influenza virus infection were treated during the 1997-1998 influenza season. Reverse transcription-polymerase chain reaction (RT-PCR) assay was used to detect the viral genome in peripheral blood and cerebrospinal fluid (CSF) samples. The results were compared with those of control influenza patients without neurological complications. Viral RNA was detected only in the peripheral blood mononuclear cells of one patient with influenza-virus-associated encephalopathy (1 of 9; 11%) and in the CSF of another patient (1 of 11;9%). RT-PCR was negative in the blood of all the controls, but the percentage of RT-PCR-positive samples in the two groups was not significantly different. Cytokines and soluble cytokine receptors in plasma and CSF were then quantified using an enzyme-linked immunosorbent assay. The CSF concentrations of soluble tumor necrosis factor receptor-1 were elevated in two patients and interleukin-6 (IL-6) was elevated in one patient with influenza-virus-associated encephalopathy. On the other hand, the plasma concentrations of IL-6 were elevated in four of nine patients. The number of encephalopathy patients who had elevated plasma concentrations of IL-6 100 pg/ml was significantly higher than that of controls (P= .01). In conclusion, the infrequent detection of the viral genome in the CSF and blood showed that direct invasion of the virus into the central nervous system was an uncommon event. Proinflammatory cytokines and soluble cytokine receptors may mediate the disease. The high plasma concentration of IL-6 could be an indicator of the progression to encephalopathy.

Adolescent↗