PubMed Health⌕ Search

Biomedical subjects

Y Minamikawa

Publications and source records attributed to Y Minamikawa.

At least 19 recordsLinked to original sources
PubMed1995

[The relationship between genotypes of HLA-DRB1 alleles and progression of bony destruction changes of rheumatoid arthritis].

The relationship between genotypes of HLA-DRB 1 alleles and the progression of bone destruction of RA patients was assessed. The genotypes of the HLA-DRB 1 alleles were determined in 329 Japanese patients with seropositive RNA by polymerase chain reaction and allele-specific oligonucleotide probe techniques. We regarded HLA-DRB 1* 0101, 0401, 0404, 0405, 1001 and 1402 as susceptible alleles of RA and classified the patients into three groups. The s/s group consisted of those with susceptible factors in both of the HLA-DRB 1 alleles. The s/n group was made up of those having one susceptible factor and one non-susceptible factor. The n/n group consisted of those possessing two non-susceptible factors. The grading of radiographic change that was evaluated by Larsen's criteria compared with the genotyped results. In the result, the median years taken to development to grade III, IV and V were significantly shorter in the s/s groups compared with that in the s/n and n/n groups. Thus, genotyping of HLA-DRB 1 can be a useful prognostic market in the progression of bone destruction of RA.

Adult↗
PubMed1994

Lateral stability of proximal interphalangeal joint replacement.

The lateral stability of the cadaver proximal interphalangeal joint was studied with an electromagnetic tracking system before and after implant replacement. Ten middle fingers were retrieved and randomly divided into two groups for joint replacement with either a silicone rubber flexible finger joint implant or a custom surface replacement prosthesis. Each finger was mounted on a fixture that allowed loading of the proximal interphalangeal joint with tension through the flexor, extensor, and intrinsic tendons. For the intact proximal interphalangeal joint under lateral stress, lateral angulation averaged 4 degrees in extension and 8 degrees with the joint in 60 degrees of flexion. Although lateral angulation increased after surface replacement prosthesis implantation when the joint was flexed more than 20 degrees, comparison with the intact joint showed no statistical difference. With the silicone implant, lateral angulation became more pronounced even in the extended position and showed a significant difference when the proximal interphalangeal joint was flexed more than 20 degrees.

Cadaver↗
PubMed1994

In vivo experimental analysis of silicone implants used with titanium grommets.

This study evaluated the titanium grommets recommended to reduce breakage by protecting hinge implants from bone edges. Silastic HP-100 (Dow Corning Wright, Arlington, TN) flexible finger implants (size 5) were used to replace one knee of 10 rabbits, and implants plus titanium grommets were used in another 10. X-ray films were taken monthly; deaths from each group were 1 animal at 2 and 4 months, 2 animals at 6, and 3 each at 12 and 16 months. X-ray films revealed that 4 of 10 implants from each group had fractured. Silicone fractures occurred identically at the proximal stem-hinge junction in both groups, destruction was always most pronounced at the dorsal surface of the proximal stems. The time from surgery to x-ray film evidence of implant fracture without grommets was an average of 9 months and with grommets 13 months. Although grommets delayed x-ray film evidence of fracture onset, after 14 months all implants in both groups of animals fractured. These findings do not support the hypothesis that grommets prevent silicone hinge implant wear or fracture in this experimental model.

Animals↗
PubMed1994

In vivo experimental analysis of silicone implants on bone and soft tissue.

We report experimentally produced silicone microparticles (synovitis) in 47 white rabbits and discuss the implications for clinical practice. Silastic HP100 (Dow Corning Wright, Arlington, TN) finger hinges (size 5) were inserted in 20 rabbit's knees. The upper tibia was replaced with Swanson design great toe implants in another 15 rabbits; articular cartilage was removed and endosteal drilling was performed in 6 animals as a "sham" arthroplasty. Small silicone blocks were inserted in the proximal tibial endosteal canal of 6 others. Animals were followed by monthly x-ray films and killed at 2, 4, 6, 12, and 16 months. Implant wear, bone surfaces, and soft tissue were examined under the operating microscope and by light microscopy; implant surfaces were examined with scanning electron microscopy. X-ray changes included reactive endosteal bone formation around implant stems as early as 1 month postoperatively; at 2-3 months the new bone line was clearest but it became progressively homogeneous and less evident. Extensive cortical erosion around the stems was observed in one third of the animals. Neither ossification nor lysis was observed around the silicone block. Proliferative synovitis was found at post-mortem examination beginning after 4 months; femoral condylar erosions were observed in most animals after 12 months. Wherever there was bone destruction, silicone particles were confirmed by x-ray spectrography.

Animals↗
PubMed1994

Rheumatoid-susceptible alleles of HLA-DRB1 are genetically recessive to non-susceptible alleles in the progression of bone destruction in the wrists and fingers of patients with RA.

OBJECTIVE: To assess the relationship between HLA-DRB1 genotypes and the progression of bone destruction in Japanese patients with RA. METHODS: The HLA-DRB1 alleles were determined by polymerase chain reaction and allele specific oligonucleotide probe techniques in 160 Japanese patients with RA. HLA-DR 0101, 0401, 0404, 0405, 1001 and 1402 were regarded as susceptible alleles of RA according to previous reports. Patients were classified into three groups (S/S, S/N and N/N group), based on the possession of two, one or no susceptible factor. The grading of radio-graphic changes in the wrists and fingers were evaluated by Larsen's criteria. The radiographic grades were first compared with the results of genotyping in the 160 cross sectional cases. A retrospective study was then conducted on a subgroup consisting of 57 cases taken from the 160 cases used for the cross sectional study. RESULTS: In the scatter diagram of the 160 cross sectional cases expressing the relationship between the stage of bone destruction and duration of RA, the regression line and the 95% confidence intervals separated the S/S group from the S/N and N/N groups in the early phase of development of bone destruction. In the retrospective study on the 57 cases the median years taken to development to stage V in the wrists after the onset of symptoms were 13.1 in the patients in the S/S group, 22.7 in the S/N group and 23.0 in the N/N group. The difference observed between the S/S and S/N group, and between the S/S and N/N group were statistically significant (p < 0.01), but that between the S/N and N/N groups was not. Thus the bone destruction in the wrists and fingers progressed more rapidly in the S/S group than in the S/N and N/N groups; and the rheumatoid susceptible alleles of HLA-DRB1 can be considered to be genetically recessive to the non-susceptible alleles in the progression of bone destructions in the wrists and fingers. CONCLUSION: Genotyping of HLA-DRB1 can be a useful prognostic marker in the early phase of RA.

Adult↗
PubMed1993

Stability and constraint of the proximal interphalangeal joint.

The kinematics of the intact proximal interphalangeal joint of 12 fresh cadaver index fingers were measured by means of an electromagnetic tracking system. The specimens were then randomly divided into two groups for ligament sectioning in two different sequences and for testing under lateral stress. Lateral stress of the intact proximal interphalangeal joints produced an average of 5 degrees of adduction and 9 degrees of supination motion throughout the arc of flexion/extension. Maximum lateral angulation was 15 degrees under 1 kg of force (30 N cm) applied at the distal end of the middle phalanx. Joint angulation increased to 20 degrees after total sectioning of the collateral ligament. Joint laxity was greatly reduced in full extension, in full flexion, and when the muscles were loaded. The proximal interphalangeal joint remained stable when one half of the collateral ligament was left intact. The results indicate that lateral stability of the proximal interphalangeal joint is provided primarily by the collateral ligament. When the lateral stress test is normal in proximal interphalangeal joint extension, an additional test in 20 to 30 degrees of flexion should be considered to avoid a false-negative result. Angulation greater than 20 degrees is abnormal and indicates a loss of collateral ligament integrity.

Electromagnetic Phenomena↗
PubMed1992

Tenosynovial injection for carpal tunnel syndrome.

Although local steroid injection into the tenosynovium is a frequent treatment for carpal tunnel syndrome, it involves some risk and is not always effective. We simulated injection on 16 fresh cadaver forearms, instilling 1 ml (group 1) or 2 ml (group 2) of methylene blue at 1 cm or 3 cm proximal to the most distal wrist crease. Passive flexion and extension were simulated 2 minutes after injection by application of traction to the appropriate digital tendons. Specimens were dissected under loupe magnification from midpalm to midforearm, dye diffusion was quantified and photographed, sections of the carpal tunnel and contents were graded for presence of dye, and average values were determined for each of the four groups. Diffusion of dye was best in group 2B in which 2 ml was injected 3 cm proximal to the distal wrist flexion crease.

Cadaver↗
PubMed1992

Wrist position and extensor tendon amplitude following repair.

After primary repair of severed extensor tendons, various methods are used to limit tendon adhesions and avoid rupture. Early passive digital motion with wrist extension (a "reverse Kleinert" protocol) has been advocated. However, there are no data to support an optimum wrist position or to indicate how much finger motion may safely be permitted. In this study we used eight fresh cadaver limbs to measure extensor tendon gliding in Verdan's zones 3 to 8 when active grip and passive extension were simulated at different wrist positions. We found that if the wrist is extended more than 21 degrees, the extensor tendon glides with little or no tension in zones 5 and 6 throughout full simulated grip to full passive extension, permitting "passive motion" exercises to minimize tendon adhesions without risking rupture. In addition, we found that up to 6.4 mm of tendon can be debrided safely and full grip can still be permitted postoperatively if the wrist is splinted at 45 degrees extension.

Cadaver↗
PubMed1992

Ideal scaphoid angle for intercarpal arthrodesis.

This experimental study was conducted to determine the best scaphoid position, measured as the radioscaphoid (RS) angle for optimum wrist motion after scapho-trapezio-trapezoid (STT) and scaphocapitate (SC) fusion and to assess the implications of radial styloidectomy on motion after STT fusion. STT and SC fusions were simulated in six fresh cadaver hands with the scaphoid in horizontal, neutral, and vertical positions with respect to the long axis of the radius seen on lateral x-rays. RS angle and wrist motion were measured on x-ray films before and after each simulated arthrodesis. Radial deviation and wrist extension increased as the RS angle increased (i.e., increased as the scaphoid became more nearly vertical). Ulnar deviation and flexion decreased as the scaphoid became more nearly horizontal. We found no statistically significant differences in RS angle between SST and SC fusions with respect to ulnar deviation, flexion, or extension. However, radial deviation was more sensitive to RS angle after STT fusion than after SC fusion, but the differences were not statistically significant. The ideal radioscaphoid angle (range) for maximal wrist motion when STT fusion is performed is 41 to 60 degrees; when SC fusion is performed, it is 30 to 57 degrees. Motion is not improved by radial styloidectomy after simulated STT fusion.

Arthrodesis↗
PubMed1991

De Quervain's syndrome: surgical and anatomical studies of the fibroosseous canal.

Anatomical variations of the first dorsal fibroosseous compartment were studied in 70 patients (38 women, 32 men) who underwent surgical release of the tendons. Seventy-one dissected forearms were also studied. De Quervain's tenosynovitis was the only diagnosis for two thirds of the patients. Nonoperative treatment for all of these patients failed. Forty-three patients (61%) had job-related symptoms. Recovery ranged from 3 to 36 months postoperatively (mean: 4.5 months). Multiple subcompartments were recorded in 47% of patients and in 75% of anatomic specimens. In 94% of the specimens, the abductor pollicis longus (APL) tendon had two to four slips, but in only two were there multiple extensor pollicis brevis (EPB) tendons. Surgeons must recognize that multiple APL tendon slips and two subcompartments are the rule, rather than the exception, in normal anatomy.

Adolescent↗