Biomedical subjects

M Aoki

Publications and source records attributed to M Aoki.

At least 397 records · Page 22Linked to original sources

PubMed1996

Mechanical characteristics of cross-stitch epitenon suture in association with various two-strand core sutures: a biomechanical study using canine cadaver tendons.

The purpose of this study was to investigate the ultimate tensile strength and stiffness of the cross-stitch epitenon suture technique in association with three different two-strand core suture techniques (the modified Kessler, Tsuge, and two-strand Savage). Twenty-four canine cadaver flexor profundus tendons were lacerated and repaired by one of the following techniques: the cross-stitch (Group 1), the modified Kessler with cross-stitch (Group 2), the Tsuge with cross-stitch (Group 3), and the two-strand Savage with cross-stitch (Group 4). Ultimate strength was determined with a tensile testing machine and stiffness was recorded by a video dimension analyser system. The ultimate strength of Group 2 (5.704 kgf) was significantly greater than that of the other techniques, followed by Group 4 (4.608 kgf), Group 3 (3.568 kgf), and Group 1 (2.935 kgf). The stiffness of Group 2 (495.8 kgf/m) was significantly greater than that of the other techniques, followed by Group 4 (369.7 kgf/m), Group 3 (225.7 kgf/m), and Group 1 (200.1 kgf/m). These results may be helpful to surgeons in deciding which core suture technique to use in association with the cross-stitch epitenon suture.

Animals↗

PubMed1996

Mechanical properties of various circumferential tendon suture techniques.

We evaluated the mechanical properties of six different circumferential tendon sutures with a variable number of suture strands. Seventy-two human cadaver flexor profundus tendons were cut and repaired using only a 6/0 polypropylene circumferential suture. The six running suture techniques were: Simple; Simple-locking; Lembert; Halsted; Cross-stitch; Lin-locking; using 10, 14 and 18 suture passes. The increased suture passes increased both tensile and gap strengths. The tensile strength of the Lin-locking technique (29 to 63 N) was significantly stronger than the others, followed by Cross-stitch (27 to 38 N), Halsted (21 to 27N), Lembert (20 to 27N), Simple (11 to 22 N) and Simple-locking (10 to 17 N). The gap strength values were between 3 to 14N, with no significant differences between the techniques. The resistance to gliding, as measured by work of flexion, was not affected by the number of strands. However, the Lin-locking significantly increased the resistance to gliding (33-36%) compared to the other techniques (6-21%); there were no significant differences between these five techniques.

Adult↗

PubMed1996

Tensile strength of cross-stitch epitenon suture.

Using a computerized tensiometer, the mechanical properties of two types of repair in the canine flexor digitorum superficialis tendon were examined. The slope and ultimate tensile strength of a cross-stitch epitenon suture were compared to those of a simple over-and-over running epitenon suture. Both epitenon sutures were combined with a modified Kessler core suture. Suture material was 6/0 monofilament nylon for the epitenon suture, and 4/0 braided polyester for core suture. Average relative values of individual ultimate tensile strength for the cross-stitch group was 245% compared to that for the running suture group. There was no discrepancy in slope between the two groups.

Achilles Tendon↗

PubMed1996

Effect of suture knot location on tensile strength after flexor tendon repair.

This study investigated the effect of increased suture material within the flexor tendon repair site on tensile strength in a canine model after in vivo healing. Four-strand modified Savage suture repairs with the knots located either inside or outside the repair site were performed in dogs. The tendons were placed on a passive-motion protocol after surgery and were biomechanically tested at 1, 3, and 6 weeks of in vivo healing. The knots-outside technique initially was 1.14 kg stronger on load-to-failure testing. After 6 weeks of healing, the knots-inside tendons had equal tensile strength (3.91 +/- 0.50 kg [inside] vs 4.16 +/- 0.66 kg [outside]). Relative tensile strength compared to initial strength showed an increase of 20% for the knots-outside technique and an increase of 67% for the knots-inside technique after 6 weeks. Suture material within the repair site did not have any deleterious effects on tensile strength and may stimulate tendon healing.

Animals↗

PubMed1996

Cyclic stress testing after in vivo healing of canine flexor tendon lacerations.

This study evaluated the effects of cyclic tension applied to lacerated and repaired canine flexor tendons after various periods of in vivo healing for up to 30 days. Final gaps obtained after cyclic stress testing were found to increase from a baseline of 0.75 +/- 0.17 mm (zero time controls) to a maximum of 1.14 +/- 0.24 mm at 3 days after repair, before returning to baseline at 10 days (0.63 +/- 0.27 mm). Gap formation at 30 days after repair (0.65 +/- 0.27 mm) was similar to that of control tendons. This canine study suggests that continued protection of flexor tendons from strong repetitive tensile, stress should extend at least through 30 days after repair.

Animals↗

PubMed1996

Effect of motion and tension on injured flexor tendons in chickens.

This study was undertaken to evaluate the individual effects of motion and tension on the healing response of injured flexor profundus tendons in chickens. Partial midsection transverse lacerations of the profundus tendons were produced in 53 chickens. Postoperatively, they were assigned randomly to four management groups: both motion and tension; only motion, no tension; no motion, only tension; no motion and no tension. Biomechanical results at 4 weeks showed that breaking strength significantly increased with both motion and tension, significantly decreased with neither, and was intermediate with only motion or only tension. Histologic evaluation generally showed the greatest cellular activity with both motion and tension, the least with neither, and an intermediate response with one or the other alone. Collagen fiber staining was increased primarily in the tension groups. The finding that both motion and tension enhance the tendon's response to injury encourages the development of active mobilization protocols following tendon repair.

Animals↗

PubMed1996

Resistance to antituberculosis drugs in Japan.

SETTING: Five years after the last survey of drug-resistant tuberculosis in Japan, a serious new phenomenon has gradually begun to appear. A nationwide survey was conducted by the Tuberculosis Research Committee. OBJECTIVE: To determine resistance patterns to five anti-tuberculosis drugs and risk factors. DESIGN: Cultures were obtained from patients hospitalized at 38 hospitals in various districts of Japan throughout 6 months, from 1 June through 30 November in 1992. Drug susceptibility testing was carried out in the national reference laboratory. RESULTS AND CONCLUSIONS: Resistance to one or more drugs was found in 5.6% of new cases and 27.8% of recurrent cases (P < 0.001). About 88% of drug resistant isolates from the new cases were resistant to one drug, while 50.8% of the drug resistant isolates from the recurrent cases had resistance to two or more drugs (P < 0.001). Resistance rates to both isoniazid and rifampin in new cases was very low (only 0.14%). Primary drug resistance rates were higher in age groups less than 60 years old, compared to those of 60 years and over (P = 0.05). Compared with the rate in Japanese patients, foreign-born individuals had a higher resistance rate in the recurrent cases (P = 0.034). This survey indicated a similar trend in resistance rates to five antituberculosis drugs to those of the last survey in 1987.

Adolescent↗

PubMed1996

Transport of chimeric proteins that contain a carboxy-terminal targeting signal into plant microbodies.

Malate synthase is a glyoxysome-specific enzyme. The carboxy-terminal tripeptide of the enzyme is Ser-Arg-Leu (SRL), which is known to function as a peroxisomal targeting signal in mammalian cells. To analyze the function of the carboxy-terminal amino acids of pumpkin malate synthase in plant cells, a chimeric gene was constructed that encoded a fusion protein which consisted of beta-glucuronidase and the carboxyl terminus of the enzyme. The fusion protein was expressed and accumulated in transgenic Arabidopsis that had been transformed with the chimeric gene. Immunocytochemical analysis of the transgenic plants revealed that the carboxy-terminal five amino acids of pumpkin malate synthase were sufficient for transport of the fusion protein into glyoxysomes in etiolated cotyledons, into leaf peroxisomes in green cotyledons and in mature leaves, and into unspecialized microbodies in roots, although the fusion protein was no longer transported into microbodies when SRL at the carboxyl terminus was deleted. Transport of proteins into glyoxysomes and leaf peroxisomes was also observed when the carboxy-terminal amino acids of the fusion protein were changed from SRL to SKL, SRM, ARL or PRL. The results suggest that tripeptides with S, A or P at the -3 position, K or R at the -2 position, and L or M at the carboxyl terminal position can function as a targeting signal for three kinds of plant microbody.

Amino Acid Sequence↗

PubMed1996

A reproducible assay of polymerase chain reaction to detect trinucleotide repeat expansion of Huntington's disease and senile chorea.

A simple and reproducible method of polymerase chain reaction (PCR) assay was established to detect trinucleotide repeat expansion for Huntington's disease (HD) using a new DNA polymerase and buffer system. The system consists of an extremely heat stable DNA polymerase (Pfu), and a buffer supplemented with ammonium sulfate and dimethyl sulfoxide. Previous methods to amplify expanded alleles for HD have been very complex in PCR conditions, but the reproducibility was sometimes very low because of repetitive sequences around the primer sequences. With the present method, strong bands for the disease alleles were reproducibly visible in a conventional agarose gel stained with ethidium bromide without using isotopes. Three cases with sporadic HD and a case with senile chorea showed expanded alleles for HD with smaller sizes of the expansion than cases with typical HD. These results showed that the present method provides a simple and reproducible way to detect HD allele, and some cases with sporadic HD and senile chorea had expanded HD alleles.

Adult↗

PubMed1996

Cloning and expression of the inorganic pyrophosphatase gene from thermophilic bacterium PS-3.

The thermophilic bacterium PS-3 ppa gene encoding inorganic pyrophosphatase (PPiase) has been cloned and sequenced. The deduced amino acid sequence was exactly the same as that determined on Edman degradation (Ichiba, T., Takenaka, O., Samejima, T. and Hachimori, A., J. Biochem. 108: 572-578, 1990) except that amino acid-70 is threonine instead of proline and two more amino acids, Asn-Lys, are present at the carboxyl terminus. The structural gene containing BamH I and Hind III restriction cleaving sites at the 5' and 3' ends, respectively, was amplified by the PCR method. Escherichia coli JM109 was transformed with a synthetic DNA, and we found that thermophilic ppa was expressed in E. coli, as judged on enzyme assaying, SDS-PAGE and immune assaying.

Amino Acid Sequence↗

PubMed1996

Founder effect in spinal and bulbar muscular atrophy (SBMA).

We analyzed the polymorphic (CAG)n and (GGC)n repeats of the androgen receptor gene in 113 unrelated X-linked spinal and bulbar muscular atrophy (SBMA) X chromosomes and 173 control X chromosomes in Japanese males. The control chromosomes had an average CAG repeat number of 21 +/- 3 with a range from 14-32 repeat units, and SBMA chromosomes had a range from 40-55 with a median of 47 +/- 3 copies. The control chromosomes had seven different alleles of the (GGC)n repeat with the range of 11 to 17; the most frequent size of (GGC)n was 16 (79%), while (GGC)17 was very rare (1%). However, in SBMA chromosomes only two alleles were seen; the most frequent size of (GGC)n was 16 (61%) followed by 17 (39%). (GGC)n size distribution was significantly different between SBMA and control chromosomes (P < 0.0001), indicating the presence of linkage disequilibrium. There was no allelic association between the (CAG)n and (GGC)n microsatellites among control subjects as well as SBMA patients, which suggests that a founder effect makes a more significant contribution to generation of Japanese SBMA chromosomes than new mutations.

Genetic Linkage↗

PubMed1996

Ender nailing for unstable surgical neck fractures of the humerus in elderly patients.

The purpose of this study was to assess the effects of stabilization of displaced and unstable surgical neck fractures of the humerus by Ender nailing followed by protected passive range of motion exercise of the shoulder. Thirty-four patients (29 women and 5 men) with such fractures were treated. The average age of patients was 69.5 years (range, 48-86 years), and the average followup period was 9.9 months (range, 6-22 months). Protected passive range of motion of the shoulder was started in 2 weeks after surgery for 25 patients and in 3 to 4 weeks for 9 patients. All patients experienced pain relief immediately after surgery. Bone union occurred at 5.9 weeks (range, 4-10 weeks) in all but 1 patient. The average range of motion of the shoulder at followup was 129.7 degrees elevation and 43.2 degrees external rotation. The average limitation of elbow extension was 4.3 degrees. The most important points of this procedure are to obtain immediate relief of pain, to stabilize the unstable fragment, and to begin protected passive range of motion of the shoulder before extensive adhesions develop.

Aged↗

PubMed1996

Successful treatment of chylothorax by bleomycin for Gorham's disease.

A patient with idiopathic osteolysis in the thoracolumbar spine who developed severe chylothorax after a spinal operation is described. Irradiation and pleural adhesion therapies with minocycline and bleomycin were undertaken to control the chylothorax. Pleural adhesion therapy with bleomycin proved effective in treating this patient. Magnetic resonance imaging was performed to detect the lesion. T1 weighted imaging was particularly useful in diagnosing the lesion and evaluating the degree of fusion in the spine.

Adult↗

PubMed1996

Hepatocyte growth factor is a novel member of the endothelium-specific growth factors: additive stimulatory effect of hepatocyte growth factor with basic fibroblast growth factor but not with vascular endothelial growth factor.

OBJECTIVE: To seek an endothelium-specific growth factor by examining the mitogenic effects of hepatocyte growth factor (HGF) on endothelial cells and on vascular smooth muscle cells (VSMC). METHODS: Rat and human endothelial cells and VSMC were employed. DNA, RNA and protein synthesis were measured by using [3H]-thymidine, uridine and leucine. Coculture of endothelial cells with VSMC was also performed to study the role of endothelial cells. RESULTS: Coculture of endothelial cells with VSMC resulted in a significant decrease in DNA synthesis of VSMC. HGF, as well as basic fibroblast growth factor (bFGF), stimulated DNA, RNA and protein synthesis by endothelial cells in a dose-dependent manner. Interestingly, co-incubation of endothelial cells with HGF and bFGF resulted in an additive stimulation of DNA synthesis. Similarly, HGF and interleukin-1 alpha and -6 stimulated DNA synthesis by coronary endothelial cells, whereas interleukin-1 beta and transforming growth factor-beta (TGF-beta) did not. However, HGF showed markedly different actions from bFGF on VSMC growth. bFGF, TGF-beta, interleukin-1 alpha, -1 beta and -6 stimulated DNA synthesis in VSMC significantly, whereas HGF did not. Finally, we examined the mitogenic effect of HGF on human aortic endothelial cells and VSMC. Incubation with HGF increased DNA synthesis and growth by endothelial cells in a dose-dependent manner, whose degree was significantly greater than those with bFGF, vascular endothelial growth factor (VEGF) and interleukin-6. Addition of HGF and VEGF showed no additive effect on DNA synthesis in endothelial cells, in contrast to those of bFGF and HGF. On the other hand, bFGF, but not HGF and VEGF, stimulated DNA synthesis in VSMC. CONCLUSION: These results demonstrate that HGF can exert stimulating effects on endothelial cell growth, but not on VSMC growth, in an additive manner with bFGF but not with VEGF. These characteristics of HGF as an endothelium-specific growth factor may provide the opportunity for a new therapeutic strategy for vascular diseases in which the abnormalities were vasoconstriction and pathological growth.

Animals↗

PubMed1996

Mitotic and meiotic stability of the CAG repeat in the X-linked spinal and bulbar muscular atrophy gene.

X-linked spinal and bulbar muscular atrophy (SBMA) occurs due to an expansion of the trinucleotide repeat (CAG)n in the androgen receptor gene. Anticipation is relatively rare in SBMA in contrast to spinocerebellar ataxia type 1 (SCAl), and dentatorubral and pallidoluysian atrophy (DRPLA) which show obvious paternal anticipation. The differences in the CAG repeat number were compared among sperm, leukocytes and skeletal muscles of SBMA patients. In SBMA, the sperm of most patients and the skeletal muscle of all patients showed the same repeat number as their leukocytes, whereas the increase in the repeat number from leukocytes to sperm was evident in SCA1 and DRPLA patients. The higher mosaicism level in sperm compared with leukocytes was common in SBMA, SCA1 and DRPLA, and the level of sperm was lower in SBMA than in SCA1 and DRPLA. Thus, spermatogenesis was suggested to be strongly associated with paternal anticipation. The mosaicism level was smaller in SBMA than in other (CAG)n expanded disorders, and smallest in the SBMA carrier females. These findings demonstrate that the CAG repeat in SBMA is relatively stable in mitotic and meiotic, processes, and there is a possibility that the lower mosaicism level of the carrier females compared with the SBMA patients is associated with X-linked recessive inheritance.

Female↗

PubMed1996

Reduction of CAG expansions in cerebellar cortex and spinal cord of DRPLA.

Recent studies have identified an unstable expansion of a CAG repeat in a gene located on chromosome 12 as a cause of dentatorubropallidoluysian atrophy (DRPLA). To investigate whether the somatic heterogeneity may relate to the selective neuronal damage caused by the disease, genomic DNA from various tissues of an autopsied patient with DRPLA was examined to compare possible variations of expanded CAG repeats for the disease. Although the size of the expanded CAG repeat from many organs was almost the same as that from peripheral lymphocytes, those from cerebellar cortex and spinal cord were unexpectedly reduced and numbers of peaks within an expanded allele were relatively strict. These results suggest that the CAG repeat is not simply expanded in the genome of the tissues that are most involved in DRPLA, but that another mechanism might be responsible for the specific neuronal death.

Adult↗

PubMed1996

Efficient oligonucleotide delivery using the HVJ-liposome method in the central nervous system.

We examined the efficiency and intracellular fate of oligodeoxy-nucleotides (ODN) in the central nervous system (CNS) after delivery with a hemagglutinating virus of Japan (HVJ)-liposome vector in vivo and in vitro. In primary cultured granular cells of the rat cerebellum, application of fluorescein isothiocyanate (FITC)-labeled ODN complexed with HVJ-liposomes in vitro resulted in strong fluorescence localized in nuclei that persisted for > or = 2 wk, in contrast to 3 days with ODN alone. In vivo ODN transfer was attempted by different approaches: infusions into the paraventricular nuclei of the hypothalamus and the lateral cerebroventricle. Injection of FITC-labeled ODN into the hypothalamus by the HVJ-liposome method produced a higher concentration and more persistent fluorescence than did injection of ODN alone. Administration of ODN into the lateral cerebroventricle with HVJ-liposomes yielded more conspicuous and prolonged fluorescence in the periventricular layer, predominantly in cell nuclei. Furthermore, the distribution of fluorescent cells was broader with the HVJ-liposome method. These results indicate that the HVJ-liposome method prolongs the half-life of ODN and concentrates them in cell nuclei. Thus it is an efficient method for ODN transfer and holds promise as a gene delivery method in the CNS.

Animals↗

PubMed1996

Tumor necrosis factor alpha immunoreactivity of rat peritoneal mast cell granules decreases during early secretion induced by compound 48/80: an ultrastructural immunogold morphometric analysis.

We used fast (seconds) and ultrafast (milliseconds) microwave energy-assisted chemical fixation protocols, postembedding immunogold staining, and a morphometric analysis to investigate the early morphological changes and the TNF-alpha immunoreactivity in the cytoplasmic granules of rat peritoneal mast cells that had been stimulated to secrete by exposure to compound 48/80. Exposure to compound 48/80 induced the development of increased numbers of cytoplasmic granules that exhibited decreased electron density; these granules often also appeared swollen. These granule alterations were accompanied by a significantly decreased proportion of granules that were positive for TNF-alpha immunoreactivity. We also calculated the density of TNF-alpha labeling/mu 2 in both dense (unaltered) and altered granules in specimens. TNF-alpha immunoreactivity was present in dense granules (regardless of whether or not the specimens had been stimulated with compound 48/80) and in cells that were fixed with either fast or ultrafast microwave energy. However, altered granules exhibited a decreased density of TNF-alpha label. These findings show that changes in the immunolocalization and/or density of TNF-alpha immunoreactivity occur very rapidly upon stimulation of rat peritoneal mast cells with compound 48/80.

Animals↗