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Biomedical subjects

K Shirakura

Publications and source records attributed to K Shirakura.

At least 19 recordsLinked to original sources
PubMed2005

Changes in biochemical parameters after anterior cruciate ligament injury.

We studied the biochemical characteristics of human knees with deficient anterior cruciate ligaments (ACL) and analysed their relationship to the time after ligamentous injury. Thirty-two patients with isolated ACL-injured knees and six healthy volunteers were enrolled. Synovial fluid samples were centrifuged after aspiration during arthroscopic examination, and aliquots of supernatant were frozen and stored at -80 degrees C. The samples were analysed for interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha, IL-6, matrix metalloproteinase (MMP)-3, and tissue inhibitor of metalloproteinase (TIMP)-1 using commercially available sandwich enzyme-linked immunosorbent assay. In fluid from ACL-injured knees, the average concentrations of IL-6, MMP-3 and TIMP-1 were highly elevated in comparison with normal controls. There was a statistically significant correlation between the concentrations of MMP-3 and IL-6. The IL-6 and TIMP-1 concentrations were interrelated. The concentration of MMP-3 remained high, independent of the duration since the injury, whereas the TIMP-1 and IL-6 levels decreased. The results suggest that the timing of the treatment of an ACL-injured knee might be of importance.

Adolescent↗
PubMed2002

Varus inclination of the distal femur and high tibial osteotomy.

We have analysed retrospectively the relationship between the axial parameters of alignment of the lower limb and the recurrence of varus deformity after high tibial osteotomy. We studied 29 patients (37 knees) with a mean age at surgery of 66 years. The mean follow-up was for 7.4 years (5 to 10.5). Recurrence of varus deformity was defined as an increase in the femorotibial angle of 3 degrees or more, compared with that obtained six months after the operation. There were four patients (four knees) with recurrence of varus deformity. They had a greater varus inclination of the distal femur than those without varus recurrence. An association between varus inclination of the distal femur and horizontal obliquity of the joint surface was observed. Excessive obliquity prevents the shift of weight-bearing to the lateral compartment, and may cause a recurrence of varus deformity after high tibial osteotomy.

Aged↗
PubMed2001

Propofol activates vanilloid receptor channels expressed in human embryonic kidney 293 cells.

Propofol (2,6-diisopropylphenol) is an intravenous anesthetic agent structurally unrelated to any other intravenous anesthetics. We examined the effect of propofol on a rat vanilloid receptor that was expressed in the human embryonic kidney (HEK) 293 cells by using calcium imaging method. Propofol caused a concentration-dependent increase in [Ca(2+)](i) in the HEK293 cells with the receptor. These responses were inhibited by removing extracellular calcium ions. The propofol-evoked increase in [Ca(2+)](i) in the HEK293 cells with the receptor was partially inhibited by capsazepine, a competitive antagonist of capsaicin. We conclude that propofol acts as an agonist for the receptor.

Anesthetics, Intravenous↗
PubMed2001

Gouty tophus of the patella evaluated by PET imaging.

We report a case of gouty tophus of the patella, a rare lesion, which was evaluated using positron emission tomography (PET). This modality, which uses a combination of an amino-acid analog emitter, L-[3-(18)F]-alpha-methyl tyrosine (FMT), which neglects malignancies, and a glucose analog emitter, (18)F-fluoro-2-deoxy-D-glucose (FDG), which neglects benign lesions, simulating the radiographic findings, may be useful for the preoperative evaluation of gouty tophus occurring in patella partita, including detection, differentiation from malignant tumors, and possible pathogenetic diagnosis.

Gout↗
PubMed2001

The natural history of disappearing bone tumours and tumour-like conditions.

We describe 27 cases of bone tumours or tumour-like lesions where there was spontaneous regression. The follow-up period was 2.8-16.7 years (average, 7.0 years). Fourteen of these cases were no longer visible on plain radiographs. Histological diagnosis included exostosis, eosinophilic granuloma, fibrous dysplasia, fibrous cortical defect, non-ossifying fibroma, osteoid osteoma and bone island. Most cases began to reduce in adolescence or earlier, although sclerotic type lesions showed their regression in older patients. All lesions thought to be eosinophilic granuloma began to regress after periods of less than 3 months, while the duration of the other lesions showed wide variation (1-74 months). As resolution of the lesions took between 2 and 79 months (mean, 25.0 +/- 20.3 months) we consider that the most likely mechanism was recovery of normal skeletal growth control. In exostosis with fracture, alteration of vascular supply may contribute to growth arrest, but not to subsequent remodelling stage. In inflammatory-related lesions such as eosinophilic granuloma, cessation of inflammation may be the mechanism of growth arrest, whilst temporary inflammation may stimulate osteogenic cells engaged in remodeling. In the sclerotic type, growth arrest is a less probable mechanism. Necrosis within the tumour and/or local changes in hormonal control, plus remodelling of the sclerotic area takes longer. Knowledge of the potential for spontaneous resolution may help in management of these tumour and tumour-like lesions of bone.

Adolescent↗
PubMed2001

Alcohol and the pancreas.

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The presentations were (1) Phenotypic alteration of myofibroblast during ethanol-induced pancreatic injury: its relation to bFGF, by Masahiko Nakamura, Kanji Tsuchimoto, and Hiromasa Ishii; (2) Activation of pancreatic stellate cells in pancreatic fibrosis, by Paul S. Haber, Gregory W. Keogh, Minoti V. Apte, Corey S. Moran, Nancy L. Stewart, Darrell H.G. Crawford, Romano C. Pirola, Geoffrey W. McCaughan, Grant A. Ramm, and Jeremy S. Wilson; (3) Pancreatic blood flow and pancreatic enzyme secretion on acute ethanol infusion in anesthetized RAT, by H. Nishino, M. Kohno, R. Aizawa, and N. Tajima; (4) Genotype difference of alcohol-metabolizing enzymes in relation to chronic alcoholic pancreatitis between the alcoholic in the National Institute on Alcoholism and patients in other general hospitals in Japan, by K. Maruyama, H. Takahashi, S. Matsushita, K. Okuyama, A. Yokoyama, Y. Nakamura, K. Shirakura, and H. Ishii; and (5) Alcohol consumption and incidence of type 2 diabetes, by Katherine M. Conigrave, B. Frank Hu, Carlos A. Camargo Jr, Meir J. Stampfer, Walter C. Willett, and Eric B. Rimm.

Alcohol Drinking↗
PubMed2001

Knee stability after repair of isolated midsubstance tears of the posterior cruciate ligament.

This study was made to compare the results after operative versus non-operative management for tears in the substance of posterior cruciate ligament. The subjects were 40 patients, half of whom were managed operatively and the other half non-operatively. End-to-end suture was performed on the operated group. The procedure was followed by cast immobilization for 4 weeks. Non-operative management consisted of immobilization in a cast for 4 weeks after arthroscopy. The average follow-up periods were 6 years 7 months and 4 years 3 months. The operated knees were significantly more stable than those of the non-operated group on stress radiographs (p<0.0001), but not to the extent of an age-matched control group (p<0.0001). The knee rating scores did not indicate any improvement of the functional outcome in the operated group. Surgery resulted in better posterior laxity than non-operative management; the achieved stability, however, was clearly less than in controls.

Journal Article↗
PubMed2000

The management of medial ligament tears in patients with combined anterior cruciate and medial ligament lesions.

The management of patients with combined medial collateral (MCL) and anterior cruciate (ACL) rupture remains controversial. We studied 25 such patients who elected to have the ACL lesion treated conservatively; 14 underwent MCL repair with early mobilization and 11 were treated with immobilization for two weeks. The mean follow up was 5.9 years (2 to 11). There was no difference in the clinical assessment of ligamentous laxity, KT-1000 measurements or Tegner activity scores between the two groups but there were significantly higher Lysholm function scores in the operated group.

Adult↗
PubMed2000

Factors affecting long-term results after arthroscopic partial meniscectomy.

The purpose of this study was to determine functional and radiographic changes on long-term followup of knees with isolated meniscal tears. Sixty-seven patients were evaluated retrospectively with an average of 12.2 years' followup using the scale of Tapper and Hoover. The criteria for the radiographic results were the Fairbank's changes as the standard comparing the preoperative and the postoperative conditions of the affected knee with the contralateral knee. Seventy-nine percent of the patients had a satisfactory outcome in terms of function. The amount of meniscus removed and the Outerbridge classification of the articular cartilage at the time of the meniscectomy were determining factors for long-term functional results. Osteoarthritic deterioration was seen in 48% of patients after the surgery, but radiographic deterioration after arthroscopic partial meniscectomy was mild on long-term followup. Medial meniscectomy and the amount of meniscus removed were risk factors for postoperative radiographic change. Age, gender, and the degree of cartilage degeneration at the time of operation, in contrast, showed no significant association. Arthroscopic partial meniscectomy for isolated meniscal injury yields favorable functional results but leads to significantly increased osteoarthritic change in the long-term.

Adolescent↗
PubMed1999

[Preliminary survey of illegal drug misuse among Japanese high school students].

For several years, amphetamine misuse by high school students has been increasing in Japan. The Japanese National Police Agency announced that the third widespread use of amphetamines has started, especially among adolescents. However, there are few data on misuse of amphetamines or other substance abuse among high school students except for solvent inhalation. This is a preliminary survey report concerning substance abuse and substance-related problems among high school students. We surveyed 3393 high school students from 8 high schools in Kanagawa Prefecture and Kyushu Area on drinking and smoking status, and experience of illegal substance use. The results showed that 5.1% of the high school students had experiences of solvents inhalation, 1.1% of marijuana use, and 0.8% of amphetamine use. Around these illegal drug misusers, there were many reserves, such as students who experienced temptation to use solvents (13.6%), marijuana (2.4%), and amphetamines (2.5%), and those who responded that they wanted to use solvents (3.7%), marijuana (3.5%), and amphetamines (2.4%) if they were tempted. The prevalence of illegal drug misusers and reserves was not significantly different between male and female students, and they were concentrated among problem drinkers by the QF Scale and among current smokers. Prevalence of illegal drug misuse among Japanese high school students can not be estimated from the results of the survey because the subjects were limited to two areas and a small number of schools.

Adolescent↗
PubMed1998

Mutation in the alpha-synuclein gene and sporadic Parkinson's disease, Alzheimer's disease, and dementia with lewy bodies.

Recently, alpha-synuclein attracted attention when Polymeropoulos and colleagues identified a missense mutation of this gene (Science 276:2045-2047, 1997), which is responsible for a form of early-onset familial Parkinson's disease (PD). Immunohistochemically, alpha-synuclein is localized in Lewy bodies, characteristic brain pathology of PD, dementia with Lewy bodies (DLB), and Alzheimer's disease (AD), suggesting that this protein may link these common neurological diseases. Exploration of the possibility that the same mutation of the alpha-synuclein gene as that in familial PD (Ala53Thr) may also confer susceptibility to sporadic PD, DLB, and AD revealed the mutation in none of the samples of 329 cases and 230 controls examined, suggesting that this mutation is not involved in these neurological diseases.

Aged↗
PubMed1998

Imaging features of subcutaneous sarcoidosis.

OBJECTIVE: This report describes subcutaneous sarcoidosis, focusing on the radiological and magnetic resonance (MR) features of the disease. DESIGN AND PATIENTS: The cases of four patients (one male and three female, age range 36-75 years) who had subcutaneous sarcoidosis with no other organs affected were reviewed. Lesions were nodular in two cases, and in the other two were diffuse. RESULTS: Computed tomography (CT) demonstrated a well-defined, homogeneous, and enhanced lesion in the nodular cases. However, in the diffuse cases, CT showed a heterogeneous, honeycomb-like appearance and little enhancement. Angiography showed a fine stain in the arterial phase. MR imaging of the nodular lesions was homogeneous with a signal intensity similar to muscle on T1-weighted images but heterogeneous with a higher signal than muscle on T2-weighted images. Diffuse lesions showed a striped or mesh pattern with intermediate signal intensity on both T1- and T2-weighted images. Contrast-enhanced MR images showed slight enhancement. CONCLUSIONS: Subcutaneous sarcoidosis should be considered in the differential diagnosis when a patient presents with the radiological and MR features described.

Adult↗
PubMed1998

The treatment of neuroleptic malignant syndrome using dantrolene sodium.

The use of dantrolene sodium (DS) in the treatment of neuroleptic malignant syndrome (NMS) was studied from the data of 21 cases of NMS, which satisfied the diagnostic criteria of Pope et al. The mean dosage of DS was 0.97+/-0.52 mg/kg per day and the mean duration of treatment was 8.3+/-5.3 days. It was confirmed that the mean duration of treatment with DS tended to be longer in the cases involving disturbance of consciousness. However, there were no significant differences in the duration of treatment or the mean daily dosage, in the cases without disturbance of consciousness regardless of any other complications and symptoms. Also, there were no significant differences in the mean duration of treatment using DS and the mean dosage of DS between five cases that were considered to be 'typical' and 16 cases that were considered to be 'incomplete'. In addition, the prognoses of these cases were good such that not even one death occurred. In 13 cases, the treatment of psychiatric symptoms with thioridazine was started without recurrence of NMS.

Adolescent↗
PubMed1998

Alcohol-related cancers and aldehyde dehydrogenase-2 in Japanese alcoholics.

Aldehyde dehydrogenase-2 (ALDH2) eliminates most of the acetaldehyde produced during alcohol metabolism. In some drinkers, a mutant ALDH2 allele contributes to diminished activity of the enzyme, dramatically increasing the risk for esophageal cancer. This study was designed to evaluate the ALDH2 gene polymorphism as a predictor of the development of cancers prevalent in Japanese alcoholics. We performed ALDH2 genotyping on lymphocyte DNA samples from Japanese alcoholic men (487 cancer-free; 237 with cancer, including 34 oropharyngolaryngeal, 87 esophageal, 58 stomach, 46 colon, 18 liver, 7 lung, 9 other sites, and 19 multiple primary cancers in two or three organs). The frequencies of the mutant ALDH2*2 allele were significantly higher in alcoholics with oropharyngolaryngeal (52.9%), esophageal (52.9%), stomach (22.4%), colon (21.7%) and esophageal cancer concomitant with oropharyngolaryngeal and/or stomach cancer (78.6%), than in cancer-free alcoholics (9.0%). After adjustment for age, daily alcohol consumption and amount of cigarette smoking, significantly increased risks (odds ratios) in the presence of the ALDH2 *2 allele were found for oropharyngolaryngeal (11.14), esophageal (12.50), stomach (3.49), colon (3.35), lung (8.20) and esophageal cancer concomitant with oropharyngolaryngeal and/or stomach cancer (54.20) but not for liver or other cancers. These results suggest a general role of acetaldehyde, a recognized animal carcinogen, in the development of human cancers.

Adult↗
PubMed1998

The influence of osteoporosis on varus osteoarthritis of the knee.

We studied 37 patients with varus osteoarthritis of the knee to determine the influence of the bone mineral density (BMD) on the varus deformity. There were 15 men (21 knees) and 22 women (38 knees). The mean age of the men was 69 years and of the women 68 years. BMD was measured in the L1-L4 spinal region using dual X-ray absorptiometry. In the women a low level of BMD was associated with varus deformity originating at the proximal tibia, but a high level was predominantly linked with deformity originating in the joint space. Similar findings were obtained in the men. Our results suggest that a low BMD predisposes to trabecular microfractures and consequently increased stress on the articular cartilage. A low BMD does not preclude osteoarthritic change in the knee.

Absorptiometry, Photon↗
PubMed1998

Calcific tendinitis in the posterior proximal thigh as a self-limited condition: pathogenic role of inflammatory responses.

OBJECTIVE: Calcific tendinitis occurs rarely in the posterior proximal thigh. We investigated whether it is self-limited and how the natural course of the disease progresses. METHODS: We treated 6 patients with no surgical intervention, and analyzed laboratory and radiological findings in the followup period of more than one year (average followup, 2.5 yrs). RESULTS: Although tendinitis was severe, rapid relief was observed within 2 weeks (average 5 days). Radiological features including extraskeletal calcifications did not change within 2 weeks, and then improved by 6 weeks. Four of 6 cases showed abnormal laboratory variables. All elevated white blood cell counts and C-reactive protein levels improved within one week with clinical resolution. In comparison with time course of the symptoms, changes in the radiological findings over time appeared not to be parallel with the clinical course, but laboratory progression appeared to correspond well with clinical resolution. CONCLUSION: Inflammatory responses to hydroxyapatite crystals may play a role in the pathogenesis of symptoms of calcific tendinitis in the posterior proximal thigh, most of which are self-limited.

Adult↗
PubMed1998

Analysis of muscle bioenergetic metabolism in rabbit leg lengthening.

The effect of lengthening on muscle metabolism was measured and correlated to the percent lengthening at early and late time points. Using the rabbit tibial lengthening model, the authors examined the effects of lengthening on the tibialis anterior muscle using phosphorus-31 magnetic resonance spectroscopy. Thirty-six rabbits were divided into five groups, four groups by percent lengthening (0%, 15%, 20%, and 25%), with each group divided into subgroups of early (end distraction) and late (12 weeks after end distraction), and the fifth group using the opposite untreated leg as control. Several parameters measuring metabolism of muscle using phosphorus-31 magnetic resonance spectroscopy analysis were compared. No changes occurred to 15% lengthening, but significant decreases were measured at 20% and 25% lengthening. After a 25% lengthening, the decreased metabolism persisted at 12 weeks after distraction, indicating the possibility of permanent damage. After 20% lengthening, the same parameters improved but never to normal levels. The authors conclude that lengthening to 15% is safe for muscle, but 20% to 25% lengthening may result in permanent metabolic damage. The current study also suggests that phosphorus-31 magnetic resonance spectroscopy may provide a viable clinical method for evaluating muscle damage during lengthening.

Adenosine Triphosphate↗