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Biomedical subjects

K Iwano

Publications and source records attributed to K Iwano.

At least 19 recordsLinked to original sources
PubMed2006

Kudo type-5 total elbow arthroplasty in mutilating rheumatoid arthritis: a 5- to 11-year follow-up.

We studied 11 patients (14 elbows) with gross rheumatoid deformity of the elbow, treated by total arthroplasty using the Kudo type-5 unlinked prosthesis, and who were evaluated between five and 11 years after operation. Massive bone defects were augmented by autogenous bone grafts. There were no major complications such as infection, subluxation or loosening. In most elbows relief from pain and stability were achieved. The results, according to the Mayo Elbow Performance Score, were excellent in eight, good in five and fair in one. In most elbows there was minimal or no resorption of the grafted bone. There were no radiolucent lines around the stems of the cementless components. This study shows that even highly unstable rheumatoid elbows can be replaced successfully using an unlinked prosthesis, with augmentation by grafting for major defects of bone.

Adult↗
PubMed2001

Kudo total elbow arthroplasty in patients with rheumatoid arthritis: a long-term follow-up study.

BACKGROUND: Improvements in the design of total elbow prostheses over the last two decades have led to better and more consistent results. The type-3 Kudo total elbow prosthesis was developed in 1980. The long-term results of use of this implant have not been reported. Because it is an unlinked prosthesis, it is not known whether preservation of the anterior oblique component of the ulnar collateral ligament at the time of implantation is important. METHODS: A type-3 Kudo total elbow arthroplasty with cement was performed in forty-seven patients (fifty elbows) with rheumatoid arthritis. Revision rates, clinical symptoms, postoperative complications, and radiographic changes were assessed eleven to sixteen years (mean, thirteen years) postoperatively. RESULTS: The overall survival rate of the prosthesis was 90% at sixteen years. The mean Mayo elbow performance scores were all poor (mean overall score, 43 points) initially. The overall score was substantially improved at both the intermediate follow-up examination (four to six years after the operation) and the late follow-up examination (eleven to sixteen years after the operation), to 81 and 77 points, respectively. The overall rate of radiolucency about the humeral component was 45% at the intermediate follow-up examination and 100% at the long-term follow-up examination. The rate of radiolucency about the ulnar component at the intermediate and late follow-up examinations was 4.3% and 8.9%, respectively. No great differences in results were found with preservation of the anterior oblique component of the ulnar collateral ligament. CONCLUSIONS: This long-term follow-up study showed acceptable results of the type-3 Kudo total elbow arthroplasty in patients with rheumatoid arthritis. Preservation of the ulnar collateral ligament does not seem to be necessary when performing this procedure.

Arthritis, Rheumatoid↗
PubMed2001

[Prospective study of pulmonary embolism after total hip or knee arthroplasty].

We investigated the incidence of pulmonary embolism after total hip or knee arthroplasty. Arterial pO2 while the patient was breathing room air was measured at pre-operative day and 5 post-operative day using a Blood Gas Analyzer. Selection of patients for perfusion/ventilation scan during this study was dependent on the results of arterial blood gas determination that was more than 10 mmHg depression Of arterial pO2 level after surgery. More than depression of that was occurred in 11 patients (17.7%). Eight of them (72.7%) detected abnormalities (V/Q mismatch) in perfusion/ventilation scan, and we diagnosed them PE. More than 70% of PE was detected by only estimating the pre and post-operative arterial pO2. It was concluded that the estimation of arterial pO2 (pre and post-operation) was useful for the detection of PE, and combining estimation of arterial pO2 with the clinical feature evaluation method, low-invasive diagnosis and rapid treatment should be possible.

Aged↗
PubMed2000

[Transient left ventricular dysfunction is still present one hour after exercise stress test: evaluation by gated SPECT with 99mTc-labeled perfusion agent].

It has been reported that quantitative gated SPECT (QGS) has revealed post-stress dysfunction of the left ventricle (LV) 30 minutes after a stress test. The purpose of this study was to determine whether post-stress dysfunction of LV is still present one hour after an exercise stress test. The subjects comprised 152 patients (124 males and 28 females, mean age 59 +/- 10 years). Exercise stress myocardial scintigraphy was performed using a one-day, stress and rest protocol. 99mTc labeled myocardial perfusion tracer, tetrofosmin, 370 MBq was injected at the end-point of a supine ergometer stress test for stress imaging. ECG gated SPECT was carried out 1 hour after injection. Three hours later, 740 MBq to 1100 MBq of 99mTc labeled myocardial perfusion tracer was injected for rest imaging. ECG gated SPECT was again performed 1 hour after injection. We divided the subjects into four groups according to the severity score of defects on the stress image and the presence or absence of fill-in; normal (NOR, n = 59), myocardial infarct (MI, n = 65), small ischemia (S-IS, n = 13) and large ischemia (L-IS, n = 15). Post-stress dysfunction is defined according to two criteria: 1) rest LVEF--post-stress LVEF > or = 5% and 2) post-stress ESV--rest ESV > or = 5 ml. The frequency of post-stress dysfunction was 3.4%, 9.1%, 23.1% and 40% in NOR, MI, S-IS and L-IS, respectively. Post-stress LV dysfunction was found to be more frequent in the large ischemia group. In conclusion, post-stress dysfunction was present 1 hour after the stress test and was more frequent in the large ischemia group.

Aged↗
PubMed1999

Total elbow arthroplasty with use of a nonconstrained humeral component inserted without cement in patients who have rheumatoid arthritis.

BACKGROUND: Most total elbow prostheses that are currently in use require cement for fixation of each component. We developed a new (type-5) prosthesis that does not need cement for fixation. METHODS: The humeral component is made of cobalt-chromium alloy, and its stem is porous-coated with a plasma spray of titanium alloy. There are two options for the ulnar component: an all-polyethylene type and a metal-backed type with a porous-coated stem. Forty-three elbows in thirty-seven patients who had rheumatoid arthritis were treated with total elbow replacement arthroplasty with use of the type-5 prosthesis. The humeral component was implanted without cement in all elbows, whereas the ulnar component was implanted without cement in eleven elbows and was fixed with cement in the remaining thirty-two. The elbows were followed for an average of three years and ten months (range, two years and six months to five years and six months). RESULTS: The clinical results were assessed according to a modification of the Mayo Clinic Performance Index. At the time of the latest follow-up, the overall result was excellent for six elbows, good for thirty-one, and fair for six. All elbows had been rated as poor before the operation. There was almost complete relief of pain in twenty-nine elbows and mild or occasional pain in the remaining fourteen. Flexion increased markedly, from an average of 104 degrees preoperatively to an average of 133 degrees postoperatively; this difference was highly significant (p < 0.001, Student t test). In contrast, extension (flexion contracture) worsened slightly, from an average of 38 degrees preoperatively to an average of 42 degrees postoperatively; this difference was significant (p < 0.05). There was one postoperative dislocation of the elbow, and ectopic bone formed in another, with recurrence of ankylosis. Both elbows had a reoperation, and a good result eventually was obtained. There were no instances of postoperative infection or neuropathy of the ulnar nerve. Radiographically, there were no radiolucent lines at the bone-metal interface of any of the humeral or ulnar stems that had been implanted without cement, suggesting solid fixation by osseointegration. CONCLUSIONS: The results of total elbow arthroplasty with use of this prosthesis appear promising. There was a high rate of relief of pain as well as of restoration of adequate function in patients in whom the elbow was severely affected by rheumatoid arthritis.

Adult↗
PubMed1998

Left coronary artery-left ventricle fistula with right coronary artery spasm.

A 72-year-old woman was admitted to our hospital for evaluation of chest pain. Coronary angiography showed a left coronary artery-left ventricle fistula. An acetylcholine provocation test induced vasoconstriction of the right but not the left coronary artery. Her chest pain was not relieved by combined therapy with isosorbide dinitrate, diltiazem and nicorandil. Because of the coronary spasm, beta-blockers could not be used. However, her chest pain was relieved after the administration of a minor tranquilizer. Thus, the patient's chest pain was unlikely to be associated with either the fistula or the coronary spasm.

Acetylcholine↗
PubMed1998

Purification and characterization of a feruloylesterase from Aspergillus awamori.

A feruloylesterase was purified from the extracellular broth of Aspergillus awamori grown on wheat bran culture. The purified enzyme gave a single band on SDS-polyacrylamide gel electrophoresis and isoelectric focusing, with an apparent M(r) of 35,000 and a pI of 3.8, respectively. The substrate specificity of the purified enzyme differed obviously from that of acetylesterase of A. awamori. The enzyme bound to microcrystalline cellulose.

Aspergillus↗
PubMed1997

An Aspergillus awamori acetylesterase: purification of the enzyme, and cloning and sequencing of the gene.

An inducible acetylesterase was purified from the culture medium of Aspergillus awamori strain IFO4033 growing on wheat-bran culture by ion-exchange, gel-filtration and hydrophobic-interaction chromatographies. The purified enzyme had an Mr of 31000 and contained Asn-linked oligosaccharides. The enzyme liberated acetic acid from wheat bran, hydrolysed only alpha-naphthyl acetate and propionate when aromatic esters were used for the substrate, and was tentatively classified as a carboxylic esterase (EC 3.1.1.1). The gene encoding acetylesterase was cloned and sequenced. The deduced amino acid sequence showed that acetylesterase was produced as a 304-amino-acid-residue precursor, which was converted post-translationally into a 275-amino-acid-residue mature protein. Part of the sequence of acetylesterase was similar to the region near the active-site serine of lipases of Geotrichum candidum and Candida cylindracea. A unique site of putative Asn-linked oligosaccharides was presented.

Amino Acid Sequence↗
PubMed1996

Infection with hepatitis GB virus C in patients on maintenance hemodialysis.

BACKGROUND: A recently discovered non-A-E hepatitis virus has been designated hepatitis GB virus C (HGBV-C), but little is known about its mode of transmission and its clinical manifestations. We studied 519 patients on maintenance hemodialysis to determine whether they were infected with HGBV-C. METHODS: HGBV-C RNA was identified in serum by a reverse-transcription-polymerase-chain-reaction assay with nested primers deduced from a non-structural region. A nucleotide sequence of 100 bp in the nonstructural region was determined on HGBV-C clones. RESULTS: HGBV-C RNA was detected on 3.1 percent of the patients on hemodialysis (16 of 519), as compared with 0.9 percent of healthy blood donors (4 of 448, P<0.03). None of the 16 patients had evidence of active liver disease, although 7 were also infected with hepatitis C virus. Eight patients with HGBV-C infection were followed for 7 to 16 years. In two patients the virus was present at the start of hemodialysis. One had a history of transfusion, and HGBV-C persisted over a period of 16 years; the other became free of HGBV-C after 10 years. In five patients, HGBV-C RNA was first detected 3 to 20 weeks after blood transfusion and persisted for up to 13 years. One patient with no history of transfusion was infected with an HGBV-C variant with the same sequence as in two of the patients with post-transfusion HGBV-C infections. CONCLUSIONS: Patients on maintenance hemodialysis are at increased risk for HGBV-C infection. This virus produces persistent infections, which may be transmitted by transfusions but may also be transmitted by other means.

Adult↗
PubMed1995

Cloning and sequencing of cellulase cDNA from Aspergillus kawachii and its expression in Saccharomyces cerevisiae.

The cDNA encoding the endo-beta-1,4-glucanase (carboxymethylcellulase; CMCase-I) from Aspergillus kawachii IFO 4308 was cloned. Nucleotide-sequence analysis of the cloned cDNA insert showed a 717-bp open reading frame that encoded a protein of 239 amino-acid residues. The predicted amino-acid sequence of the mature protein had considerable homology with the protein sequence of the FI-CMCase of Aspergillus aculeatus. The cDNA was introduced into Saccharomyces cerevisiae. The expressed enzyme had carboxylmethylcellulase activity, identified by clear zones on a CMC-agar plate after Congo Red staining.

Amino Acid Sequence↗
PubMed1995

Cholesterol emboli following percutaneous transluminal coronary angioplasty as speculated by toe skin biopsy.

A 55-year-old man required hemodialysis for acute renal failure 3 days after repeat percutaneous transluminal coronary angioplasty (PTCA). Bilateral acrocyanosis and necrotic lesions of the toes occurred 10 days after PTCA. Skin biopsy samples revealed needle-shaped cholesterol crystals of the intraluminal clefts in his small arteries. He was diagnosed with cholesterol emboli presenting as blue toe syndrome. The conditions improved with anticoagulation and vasodilation, but improvement in renal function was temporary. He later required maintenance hemodialysis. Cholesterol emboli following PTCA are life threatening because they are difficult to diagnose and can cause severe complications.

Angioplasty, Balloon, Coronary↗
PubMed1994

Cementless or hybrid total elbow arthroplasty with titanium-alloy implants. A study of interim clinical results and specific complications.

Twenty-six patients (32 elbows) with rheumatoid arthritis had a total elbow arthroplasty with insertion of a cementless prosthesis. The humeral component was made of titanium alloy and it was fixed without cement in all elbows. The patients were followed for an average of 3 years 1 month (range, 2 years 2 months to 4 years 4 months). A good result was seen in 25 elbows, a fair result in 2, and a poor result in 5. The reason for the poor results was a breakage of the humeral component at the junctional portion of its stem. In all five of these elbows a marked resorption of bone mass within the condylar portion of the humeral component was observed on the lateral radiograph. The five elbows with a poor result had a revision operation, and in each of these black staining of the soft tissues within the joint was seen. This tissue metallosis due to wear debris of the titanium alloy was responsible for the osteolysis within the condylar portion. It became clear from this study that even in a non-weight-bearing joint, such as the elbow, titanium alloy may wear and result in tissue metallosis when used as a bearing surface of the implant. However, it was also found that in the majority of the elbows an establishment of the biologic fixation of the porous-coated stem could be achieved by use of this alloy.

Adult↗
PubMed1993

High carrier rate after hepatitis B virus infection in the elderly.

An outbreak of hepatitis B virus infection occurred in a nursing facility; it involved 31 patients with sequelae of cerebral vascular accidents (15 men and 16 women; mean age, 77.4 +/- 9.3 yr). HBsAg disappeared within 6 mo in 9 patients and persisted during an observation period of more than 6 mo in 13; the remaining 9 patients were lost to follow-up while they carried HBsAg. Thus 13 of 22 patients followed (59%) became HBsAg carriers. We amplified a part of the S gene (436 nucleotides) with polymerase chain reaction on hepatitis B virus DNA from 12 randomly selected patients. The sequences of nine patients were the same as that of a nursing assistant who was an HBsAg carrier and suspected as the source of infection; it differed by only 1 or 2 (< 0.5%) nucleotides from those of the remaining three patients. Between the group of nine patients with transient HBV infection and the 13 patients with persistent HBV infection, we found no differences in age or sex or in parameters of nutrition or immunocompetence. These results indicate a high incidence of HBV carrier state in the elderly.

Adolescent↗
PubMed1992

Hepatitis C virus infection in medical personnel after needlestick accident.

Hepatitis C virus infections in medical personnel after needlestick accidents have been documented generally by detection of seroconversion to a hepatitis C virus nonstructural region antigen, c100-3 (a marker of infection). We tested for hepatitis C virus core-derived antibodies and genomic RNA in addition to c100-3 antibody in 159 cases of needlestick exposure that did not involve patients positive for HBsAg. Of these we found 68 cases with index patients positive for both hepatitis C virus RNA and antibodies and members negative for antibodies to HCV core or c100-3 before the needlestick accidents. Seven of these medical personnel became infected with hepatitis C virus after the accidents. Their hepatitis was generally subclinical or self-limited and transient, except for one patient in whom liver enzyme elevation persisted along with the antibodies. In our study, the risk of hepatitis C virus transmission from a single needlestick accident with hepatitis C virus RNA-positive blood was 10%, considerably higher than the 4% estimated in a previous study. We found that donor blood with antibody to an hepatitis C virus core-derived peptide with enzyme-linked immunosorbent assay optical densities greater than 2.0 carried a significant risk of transmitting hepatitis C virus to needlestick victims. No hepatitis C virus seroconversions occurred in medical personnel exposed to hepatitis C virus antibody-negative or hepatitis C virus RNA-negative blood; however, one such exposure resulted in a very mild non-A, non-B, non-C hepatitis.

Health Personnel↗
PubMed1991

Surgical treatment of subaxial cervical myelopathy in rheumatoid arthritis.

Between 1978 and 1988 a total of 27 operations were performed on 26 patients for cervical myelopathy due to rheumatoid disease in the subaxial spine. Three different causes were recognised: the first group had cord compression due to subluxation of the cervical spine itself (6 patients); the second had cord compression occurring from in front, with rheumatoid lesions of vertebral bodies or discs (6); the third had compression from behind the cord due to granulation tissue within the epidural space (14). Group I was treated by closed reduction of the subluxation followed by surgical fusion either from in front or behind. Group II was decompressed by subtotal resection of the involved vertebral bodies and discs, followed by interbody fusion. The patients in group III were decompressed by laminectomy and excision of fibrous granulation tissue from the epidural space. Good recovery of neurological function was observed after 18 of the operations, fair recovery after five, poor recovery followed three, and one was worse. Myelopathy recurred in four patients, all of whom had had anterior interbody fusion.

Aged↗
PubMed1990

[Causes of death in patients with rheumatoid arthritis--analysis of 117 cases for 13 years].

One hundred seventeen deaths of RA patients (30 males and 87 females) at National Sagamihara Hospital for 13 years (1975-1988) were analysed. The average duration of disease were 10.5 years in male patients and 17.7 years in female. The average life span of the patients with RA, revealing 65.8 years in male and 63.7 years in female, were much shorter than of general population. The causes of all deaths were investigated by ourselves and/or autopsy. The autopsy was performed in 56.6%. The most common causes of death in RA patients were infectious diseases (20.5%), respiratory diseases (16%, mainly interstitial pneumonia and chronic obstructive lung diseases), and gastrointestinal diseases (14.7% chiefly perforation or bleeding of peptic ulcer). The distribution of causes of death in RA patients was quite different from in general population. The gastrointestinal disease decreased from 20% in the early half (1975-1981) to 12.6% in the latter half (1982-1987). It seems likely that H2-receptor antagonist played a major role for preventing the death by perforation or bleeding of ulcer, because the drug has been used since 1982 in Japan. Renal insufficiency including amyloidosis increased markedly in the latter half (14.9%) compared with in the early half (6.7%). Frequency of infectious diseases, respiratory diseases, and basilar impression remain unchanged in all course. Although our study are case-analysis in only one institute and further study will be necessary, the accumulation of the data investigated by rheumatologist will be helpful to grasp correct cause of death in patients with RA.

Adult↗
PubMed1990

Total elbow arthroplasty with a non-constrained surface-replacement prosthesis in patients who have rheumatoid arthritis. A long-term follow-up study.

Thirty-seven elbows in thirty-six patients who had rheumatoid arthritis had a total elbow arthroplasty with insertion of a non-constrained surface-replacement prosthesis. The patients were followed for an average of nine years and six months, the longest follow-up being seventeen years. A good result was seen in twenty-nine elbows; a fair result, in one; and a poor result, in seven. The reasons for the poor results were gross posterior displacement of the humeral component in five elbows, persistent subluxation with pain in one, and recurrent ankylosis in one. Of the five elbows that had gross posterior displacement, four had a revision operation with a new humeral component, and a satisfactory result was eventually achieved. Radiographic examination revealed various degrees of proximal subsidence of the humeral component in 70 per cent of the elbows. However, in most of the elbows the subsidence was not progressive and was compatible with a good clinical result. In contrast, the rate of loosening of the ulnar component was low; loosening was seen in only 5 per cent of the elbows. Seventeen elbows were followed for ten years or more, and comparison of the clinical results in the intermediate period with those at the most recent review revealed that the results improved with time. Because of the number of elbows in which subsidence of the humeral component developed, we now use a humeral component with an intramedullary stem, and were no longer recommend the use of our Type-1 and Type-2 prostheses.

Adult↗