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Biomedical subjects

H Kanai

Publications and source records attributed to H Kanai.

At least 19 recordsLinked to original sources
PubMed2000

High prevalence of herpes simplex virus type 2 in acute retinal necrosis syndrome associated with herpes simplex virus in Japan.

PURPOSE: To determine the type of herpes simplex virus in acute retinal necrosis syndrome associated with herpes simplex virus. METHODS: Herpes simplex virus type 1, herpes simplex virus type 2, varicella-zoster virus, Epstein-Barr virus, and cytomegalovirus were examined by polymerase chain reaction in intraocular specimens from 16 patients with acute retinal necrosis syndrome. Anti-herpes simplex virus type 1 and anti-herpes simplex virus type 2 type-specific antibodies in serum from the patients were detected by enzyme immunoassay. RESULTS: Of 16 patients with acute retinal necrosis syndrome, seven were polymerase chain reaction positive for herpes simplex virus type 2 and nine were positive for varicella-zoster virus. Anti-herpes simplex virus type 2 antibody was positive and anti-herpes simplex virus type 1 antibody was negative in the sera of the seven patients with herpes simplex virus type 2 DNA-positive acute retinal necrosis syndrome. In contrast, anti-herpes simplex virus type 2 antibody was absent in all nine varicella-zoster virus DNA-positive acute retinal necrosis syndrome patients. CONCLUSION: Herpes simplex virus type 2 has been demonstrated to be the major causative agent in acute retinal necrosis syndrome associated with herpes simplex virus by molecular biological and serological methods. Negative preexisting anti-herpes simplex virus type 1 antibody may play an important role in acute retinal necrosis syndrome associated with herpes simplex virus type 2.

Adolescent↗
PubMed2000

Onset of pulsatile waves in the heart walls at end-systole.

We have previously developed a novel ultrasonic method, namely, the phased tracking method, for accurately tracking the movement of the heart wall based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. With this method, it is possible to accurately detect small-amplitude velocity signals of less than a few micrometers of the heart wall that are superimposed on the motion of the heart wall due to the heart beat. There are several remarkable pulsatile waves during one cardiac cycle in the resultant velocity signals, some of them being commonly obtained for both healthy subjects and patients. These pulsatile waves cannot be recognized in standard echocardiography M-mode images. In this paper, by focusing on one pulsatile wave that occurs around the end-systole, the physiological meaning of these is considered based on various in-vivo experiments. The pulsatile wave measured by this novel ultrasonic method will offer potential for a quantitative assessment of myocardial viability.

Adult↗
PubMed2000

Real-time velocimetry for evaluation of change in thickness of arterial wall.

We previously developed a new method, namely, the phased tracking method, for accurately tracking the movement of the heart wall and arterial wall based on both the phase and magnitude of the demodulated signals to determine the instantaneous position of an object. By this method, the local change in wall thickness during one heartbeat can be determined. We have now developed a real-time system for measuring change in thickness of the myocardium and arterial wall. In this system, four high-speed digital signal processing (DSP) chips are employed for obtaining the initially developed method in real time. The tracking results for both sides of the wall are superimposed on the M (motion)-mode image in the workstation, and the thickness changes of the arterial wall are displayed in real time. Using this system, reported herein, velocity signals of the arterial wall with amplitudes less than several micrometers can be successfully detected in real time with sufficient reproducibility. The elasticity of the arterial wall is evaluated by referring to the blood pressure. In in vivo experiments, the rapid response of the change in wall thickness of the carotid artery to the dose of nitroglycerine (NTG) is evaluated for a young healthy subject and a young smoker. This new real-time system offers potential for quantitative diagnosis of early-stage atherosclerosis by the transient evaluation of the rapid response of the cardiovascular system to physiological stress.

Adult↗
PubMed2000

Therapeutic effects of ulinastatin on experimental crescentic glomerulonephritis in rats.

Ulinastatin is a potent protease inhibitor purified from the human urine that has been used clinically to treat acute pancreatitis and circulatory shock. In the current study, we evaluated the therapeutic effects of Ulinastatin in a rat model of crescentic glomerulonephritis (CrGN) and investigated its putative mechanisms. Wistar-Kyoto rats were injected with nephrotoxic serum and received daily intraperitoneal injection of Ulinastatin. Ulinastatin treatment significantly reduced proteinuria and glomerular crescentic formation. Moreover, glomerular infiltration of neutrophils and ED1+ cells (monocytes/macrophages) was significantly suppressed by Ulinastatin. In contrast, the glomerular deposition of heterologous (rabbit) and autologous (rat) antibodies was not changed. Neither serum complement activation nor the anti-rabbit immune response was affected by Ulinastatin administration. Our results suggest that Ulinastatin has preventive effects on rat experimental CrGN, mediated at least in part by inhibiting intraglomerular infiltration of inflammatory cells.

Animals↗
PubMed2000

[Hypertensive putaminal hemorrhage with extensive subarachnoid hemorrhage presenting extravasation of contrast material during angiography: case report].

The authors describe a case of hypertensive putaminal hemorrhage with extensive subarachnoid hemorrhage. On admission, the patient aged 71 presented right-sided motor weakness. CT scan on admission revealed left putaminal hemorrhage with extension into the ipsilateral thalamus and lateral ventricle as well as into the subarachnoid space of the suprasellar, ambient, interhemispheric and contralateral sylvian cisterns. To exclude vascular lesions, left carotid angiography was performed just after admission. The lateral view was unremarkable, but the anterior-posterior view demonstrated extravasation of contrast material from the left lateral lenticulostriate artery. The angiographic sylvian point was shifted to the lateral side. No abnormal vessels were revealed. CT scan after angiography showed exacerbation of both intracerebral and subarachnoid hemorrhages, but the consciousness level was unchanged. CT-guided stereotactic aspiration of the hematoma was performed 4 days after the onset, but failed to remove much hemtoma. The patient died of aspiration pneumonia 9 days after onset. The authors emphasize that extensive subarachnoid hemorrhage in cases with hypertensive putaminal hemorrhage may be an important finding which indicates high risk of rebleeding.

Aged↗
PubMed2000

Cerebral ischemia as a causative mechanism for rapid progression of brain atrophy in chronic hemodialysis patients.

BACKGROUND: It has been found that brain atrophy develops more rapidly in patients with end-stage renal failure after initiation of dialysis therapy. The present study was designed to analyze the relationship between brain atrophy and asymptomatic ischemic brain lesions. PATIENTS AND METHODS: Magnetic resonance imaging (MRI) was performed for the evaluation of brain atrophy and ischemic lesions. Brain atrophy was assessed by the ventricular-brain ratio (VBR), calculated as the ratio of the ventricular area to the whole brain area on the maximum MRI slice. The severity of periventricular hyperintensity (PVH) and the number of lacunae were also regarded as ischemic brain lesions. Fifty-five patients undergoing maintenance hemodialysis (HD) without clinically overt neurological signs and symptoms, with a mean age of 52 +/- 11 (SD) years and a mean HD duration of 7 +/- 6 (SD) years were subjected. VBR and its relationship to ischemic brain lesion data were compared to those in 35 non-HD patients (controls), with a mean age of 42 +/- 14 (SD) years. RESULTS: The VBR, the number of lacunae and the severity of PVH tended to increase with age in HD. The VBRs at all age groups were significantly higher in HD than in controls (7.0 vs 3.7% at the 4th decade, p < 0.05; 8.4 vs 5. 9% at the 5th decade, p < 0.05; 9.6 vs 5.4% at the 6th decade, p < 0.05; and 11.6 vs 6.3% at the 7th decade, p < 0.05). HD patients had significantly higher number of lacunae and had more advanced PVH than did controls. Both the number of lacunae and the severity of PVH were significantly correlated to VBR in HD. CONCLUSION: In conclusion, the rapid progression of brain atrophy was related to the asymptomatic ischemic brain lesions in our HD patients. Such data indicated that cerebral ischemia might be a causative mechanism of brain atrophy in chronic hemodialysis patients.

Atrophy↗
PubMed1999

Study of the relation between fluid distribution change in tissue and impedance change during hemodialysis by frequency characteristics of the flowing blood.

Erythrocyte orientation and deformation cause differences in impedance between flowing and resting blood. Through theoretical calculation and experimental measurements, we studied the effects of these factors on blood impedance. The size and shape of the erythrocyte and the conductivity of the interior medium of the erythrocyte change when the osmotic pressure of plasma is changed. From experimental results, we obtained the following: when the size of the erythrocyte becomes larger than the normal size due to the osmotic pressure change, the beta dispersion frequency decreases and the intra- and extracellular fluid resistance increase. These experimental results corroborate that the change of tissue impedance like muscle impedance during hemodialysis is caused by the change of the fluid distribution and the change of ionic concentration of the electrolyte in tissues during hemodialysis. Also, we could estimate the relative change value of the intra- and extracellular fluid volume by the impedance method, if there were no ionic concentration change in the electrolyte. It would be very difficult to estimate the absolute change value of them because a shadow effect due to the cells depends greatly upon the shape and size of the cells and the cell concentration.

Anisotropy↗
PubMed1999

Orientation and deformation of erythrocytes in flowing blood.

The effects of flow on the changes of electrical resistivity and light-scattering characteristics of blood are experimentally and theoretically discussed. Studies indicate that most erythrocytes deform and orient themselves in the flow direction when blood flows in a conduit. Such oriented blood shows anisotropic properties. Anisotropic electrical resistivity of flowing blood is measured in three rectangular directions with a measurement cell of coaxial cylindrical type. From these experimental results, the orientation and deformation of erythrocytes are discussed. The orientation ratio and the deformation are calculated using a simplified spheroidal model of an erythrocyte. Calculated results show that the fractions of erythrocytes with their short axis parallel to each direction and the equivalent axis ratio for a simplified spheroidal model change with the shear rate of flow.

Blood Flow Velocity↗
PubMed1999

Colonna capsular arthroplasty: a 33-year follow-up of four patients.

We evaluated the results of Colonna capsular arthroplasty in 4 patients with unilateral congenital dislocation of the hip. All of these patients were female, aged 10-14 years at the time of surgery, and 42-50 years at the time of follow-up. The most striking finding in this study was the good ability to walk. Although radiographs showed considerable joint degeneration, all of these patients had only mild to moderate pain in the hip.

Adolescent↗
PubMed1999

Spontaneous subcapital femoral neck fracture complicating a healed intertrochanteric fracture.

A spontaneous subcapital femoral neck fracture is an uncommon complication of a healed intertrochanteric hip fracture. To determine the etiology of this complication, 274 patients who had been treated for intertrochanteric hip fractures were followed up over an 8-year period from June 1988 to June 1996. We found 7 fractures of the subcapital femoral neck without a history of a trauma. The remaining 267 patients were defined as the control group. All seven patients with fractures of the subcapital femoral neck were women, and their average age at the time of compression hip screw (CHS) fixation was 83 years (range 74-92 years). The subcapital fractures occurred between 4 and 36 months after CHS fixation. The difference in the Singh index between the patient and control groups was statistically significant (P < 0.01). However, with regard to the position of the screw, spinal score, age, ambulatory ability, height, weight, and intertrochanteric fracture type (Jensen type), the differences between the patient and control groups were not statistically significant. Based on our findings, we conclude that a high grade of osteoporosis is the most important predisposing factor in the spontaneous development of a subcapital femoral neck fracture after a healed intertrochanteric hip fracture.

Aged↗
PubMed1999

Rotational acetabular osteotomy for the treatment of dysplastic hips with end-stage osteoarthrosis--a biological alternative to total hip arthroplasty?

We evaluated the results of rotational acetabular osteotomy (RAO) for the treatment of dysplastic hips with end-stage osteoarthrosis. Sixteen patients, aged 15-45 years at the time of surgery, were reviewed at a mean follow-up of 8 years (range 3-17 years). Remodeling of the hip joint occurred in half of the patients, with significant clinical improvement. A subsequent total hip arthroplasty, however, was done within 2 years after RAO in two other patients who had had large bone cysts in the femoral head and acetabulum. We suggest that RAO may be the procedure of choice for selected young patients, especially teenage patients, to postpone total hip arthroplasty.

Acetabulum↗
PubMed1999

Study of the cause of the temperature rise at the muscle-bone interface during ultrasound hyperthermia.

Undesirable temperature rise at the muscle-bone interface has been one of the major problems during ultrasound hyperthermia treatment. In this study, we examined by both computer calculation and phantom experiment the cause of this problem. Ultrasound penetrates a bone in two different waveforms, longitudinal and transversal. The transmission coefficient of these two waves vary greatly with the incident angle. From both theoretical and experimental results, the incident angle dependency of the interface heat was confirmed. When the incident angle is less than the critical angle of the longitudinal wave, the main cause of the temperature elevation is the absorption of the longitudinal wave in the bone. When the incident angle is larger than the critical angle of the longitudinal wave, the transversal wave becomes the major cause of the heat generation. At the incident angles larger than the critical angle of the transversal wave, no temperature rise is produced by the absorption of the ultrasound at the bone; the incident longitudinal wave, strengthened by the reflected wave, is absorbed in the muscle just in front of the bone. The heat generated in the muscle is transported to the interface so that the temperature of the interface and bone increases slightly.

Bone and Bones↗
PubMed1999

Adenovirus strains of subgenus D associated with nosocomial infection as new etiological agents of epidemic keratoconjunctivitis in Japan.

Adenovirus strains of a new type were isolated from patients with epidemic keratoconjunctivitis. They were not completely neutralized by any antiserum against adenovirus prototypes. PCR followed by restriction endonuclease analysis demonstrated that they were type 8. PCR followed by sequencing revealed a high homology rate between them and type 9.

Adenoviridae↗
PubMed1999

The increase of parathyroid hormone-related peptide and cytokine levels in synovial fluid of elderly rheumatoid arthritis and osteoarthritis.

We simultaneously measured the concentrations of parathyroid hormone related peptide (PTHrP) and cytokines in synovial fluid (SF) to clarify the relationship between PTHrP and cytokine network in the SF of elderly patients with arthritis. SF was collected from knee joints of five RA patients aged 66+/-11 years old and nine osteoarthritis (OA) patients aged 80+/-9 years old. PTHrP in SF was measured by enzyme-linked immunosorbent assay (ELISA), whereas tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-8 (IL-8) in SF were all measured by ELISA. The PTHrP levels in the SF of RA patients (2.56+/-0.89 pmol/l) were significantly (p<0.05) higher than those of OA patients (1.66+/-0.17 pmol/l). TNF-alpha, IL-1beta, IL-2 and IL-6 concentrations in SF of RA were also significantly higher than those in SF of OA (TNF-alpha 22.5+/-14.8 vs 4.8+/-3.0 pg/ml, p<0.01; IL-1beta 11.8+/-11.4 vs 1.4+/-1.3, p<0.05; IL-2 59.9+/-46.6 vs 12.5+/-8.0 pg/ml, p<0.05; IL-6 18424+/-8901 vs 3547+/-2948 pg/ml, p<0.01). The concentrations of IL-4 and IL-8 in SF of RA were similar to those of OA. Immunohistochemical studies revealed the presence of immunoreactive PTHrP in synovial fibroblasts from RA and OA. Among cytokines, only IL-6 was positively correlated with PTHrP levels in SF (r=0.685, p<0.01). In the culture of synovial cells from RA and OA, PTHrP was produced in RA more than OA after phorbol 12-mysistate 13-acetate (TPA) stimulation. These results indicate that PTHrP and cytokines, especially IL-6, might be involved in the inflammatory processes of elderly RA and OA. This is the first study in which PTHrP and cytokine levels were simultaneously examined in synovial fluid of elderly RA and OA.

Aged↗
PubMed1999

[Genome analysis with restriction endonucleases recognizing 4- or 5-base pair sequences of adenovirus type 4].

PURPOSE: To ascertain the chronological change of subgenome types of adenovirus type 4 (Ad 4) through DNA analysis. MATERIALS AND METHODS: We evaluated sixteen Ad 4 strains from patients with acute viral conjunctivitis at four eye clinics in Sapporo, northern Japan. Seven strains were obtained from December 1993 through March 1994 (first period). Nine strains were obtained from March through May in 1995 (second period). These strains were analysed using DNA restriction endonucleases recognizing 4- or 5-base-pair sequences, Taq I and Hin f I. RESULTS: The genome type of sixteen strains was Ad 4 a. Seven strains in the first period showed the same subgenome type. Nine strains in the second period showed two subgenome types: five strains showing the same subgenome type as in the first period, and four showing a different subgenome type. The two subgenome types were similar in DNA pattern, suggesting that both were derivatives of a common subgenome type. All the sixteen strains were a new subgenome type which was different from those previously isolated during 1985-1989. CONCLUSION: The subgenome types of Ad 4 in 1993-1995 have changed from those in 1985-1989.

Adenoviruses, Human↗
PubMed1998

Non-invasive estimation of human left ventricular end-diastolic pressure.

Sato et al. (Electronic Letters 32, 949-950, 1996) reported that one can obtain a non-invasive estimate of left ventricular (LV) pressure at around end-diastole in an isolated canine preparation. In this study we examined whether this method can be applied to humans. Using the method proposed by Kanai et al. (IEEE. Trans. UFFC, 43, 791-810,1996), we detected small amplitude LV vibration from an ultrasonic pulse Doppler signal reflected from the interventricular septum in five patients (44-63 y.o., male;4, female;1). We measured the oscillation frequency of the LV wall through the wavelet transform of small amplitude LV vibration, and calculated LV pressure at around end-diastole from the values of oscillation frequency, internal radius and wall thickness using Mirsky's equation. The estimated LV pressures at around end-diastole were similar to end-diastolic pressure measured directly by cardiac catheterization. These results show the possibility that this method allows for the non-invasive estimate of LV pressure at around end-diastole, and furthermore provides the basis for future clinical applicability of this technique.

Adult↗