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Biomedical subjects

S Ochi

Publications and source records attributed to S Ochi.

At least 19 recordsLinked to original sources

Assessment of implant mobility at second-stage surgery with the Periotest: DICRG Interim Report No. 3. Dental Implant Clinical Research Group.

Many of the presently used methods of evaluating osseointegration at implant uncovering are highly subjective. The Periotest is claimed to offer a more objective means to assess osseointegration by means of microcomputer-controlled percussion. Investigators involved in a long-term clinical study of dental implants being conducted by the Dental Implant Clinical Research Group used the Periotest to evaluate the mobility associated with all study implants at second-stage surgery and correlate the Periotest values with various bone densities. The Periotest values for 1,838 root form implants ranged from -8 to +25. Implants that appeared to be osseointegrated at uncovering recorded a mean Periotest value of -3.37 +/- 3.25, while nonosseointegrated implants had a mean Periotest value of +13.87 +/- 14.27. Mean Periotest values were -3.82 +/- 3.04 for quality 1 bone, -3.70 +/- 3.06 for quality 2 bone, -3.31 +/- 3.18 for quality 3 bone, and -1.29 +/- 3.57 for quality 4 bone. The Periotest has the potential of being a valuable instrument for assessing the status of osseointegration at second-stage surgery.

Alveolar Process

The influence of implant type, material, coating, diameter, and length on periotest values at second-stage surgery: DICRG interim report no. 4. Dental Implant Clinical Research Group.

Many of the presently used methods of evaluating osseointegration at second-stage surgery are highly subjective. The Periotest is claimed to offer a more objective means to assess osseointegration by means of microcomputer-controlled percussion. In 1991 the Dental Implant Clinical Research Group initiated a long-term clinical study in cooperation with the Department of Veterans Affairs to investigate the influence of implant design, application, and site of placement on clinical performance and crestal bone height. As part of this investigation, the Periotest values for 1,565 root form implants were determined at second-stage surgery and correlated with type, material, coating, diameter, and length. Hydroxyapatite-coated implants and increased implant diameter and length produced Periotest values that indicated a greater extent of stability as compared with noncoated implants with shorter diameters and lengths. Hydroxyapatite-coated cylinder-type implants yielded the most favorable Periotest readings. Not only does the Periotest have the potential of being a valuable instrument for assessing implant mobility at second-stage surgery, but it also appears to have the capability of determining slight differences in the implant-bone complex.

Dental Alloys

The effect of smoking on implant survival at second-stage surgery: DICRG Interim Report No. 5. Dental Implant CLinical Research Group.

Smoking has been reported to have a deleterious effect on the oral cavity. Research has associated smoking with oral cancer, periodontal disease, leukoplakia, stomatitis nicotina, and impaired gingival bleeding. In 1991 the Dental Implant Clinical Research Group initiated a prospective, randomized clinical study in cooperation with the Department of Veterans Affairs to investigate the influence of implant design, application, and site of placement on long-term clinical performance and crestal bone height. Over 70 dental and medical history variables and exclusion factors were analyzed to determine relationships, if any, with implant failure at the time of second-stage surgery. The variables were analyzed separately for individual implants, cases (prostheses), and patients. The cases ranged from one to five implants each, and more than one case from a single patient could be included in the investigation. At this interim analysis, 2,066 implants have been placed representing 433 cases in 310 patients. With regard to implant failure rates, possible exclusion variable (9) and medical history variables (39) were not found to be statistically significant. For the dental history variables (23), only the question related to smoking was statistically significant on an implant, case, and patient basis (P < 0.007). Results of this interim analysis suggest that smoking is detrimental to implant success.

Chi-Square Distribution

Patient demographics and implant survival at uncovering: Dental Implant Clinical Research Group Interim Report No. 6.

Implant prognoses for healthy elderly patients have been found to be comparable with those reported for younger patients. In 1991, the Dental Implant Clinical Research Group initiated a prospective, randomized clinical study in cooperation with the Department of Veterans Affairs to investigate the influence of implant design, application, and site of placement on long-term clinical performance and crestal bone height. As a result of the large sample size and wide range of patient ages, the study provided an opportunity to determine if age correlates with implant survival. Interim analysis of 2,132 root form implants at uncovering on an implant, case, and patient basis suggests that implant survival does not appear to be influenced by age in the largely white, male sample.

Adult

Second-stage failures related to bone quality in patients receiving endosseous dental implants: DICRG Interim Report No. 7. Dental Implant Clinical Research Group.

The quality of bone plays an important role in the long-term clinical success of dental implant treatment. An interim evaluation of the relationship between bone quality and the incidence of failure at second-stage surgery is presented. The data include 2,131 root form implants placed by the Dental Implant Clinical Research Group over the past three years. Trends to date suggest differences in the rates of osseointegration among the various bone qualities. Quality 1 bone experienced the greatest failure rate, whereas quality 2 and quality 3 bone had the lowest failure rates.

Alveolar Bone Loss

Regulation of Clostridium perfringens alpha-toxin-activated phospholipase C in rabbit erythrocyte membranes.

The rapid phosphatidic acid (PA) formation induced by Clostridium perfringens alpha-toxin was stimulated by AlF4- in rabbit erythrocyte membranes. GTP[gamma S] [guanosine 5'-O-(3-thiotriphosphate)] stimulated the rapid 1,2-diacylglycerol formation and inositol 1,4,5-trisphosphate release induced by the toxin. On the other hand, treatment of erythrocyte lysates with phorbol 12-myristate 13-acetate (PMA) resulted in inhibition of toxin-induced PA production, and long-term PMA or 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) treatment of the lysates led to stimulation of PA formation. Furthermore, treatment of erythrocytes with the toxin caused an increase of protein kinase C activity in membrane fractions. The results suggest that toxin-induced PA formation is mediated by endogenous phospholipase C regulated through GTP-binding protein and protein kinase C in rabbit erythrocytes.

Animals

[A case of hemifacial spasm associated with a cerebellar hematoma].

This is a report of a hemifacial spasm associated with a cerebellar hematoma. A 60 year-old female was admitted to our hospital due to severe vertigo and nausea. On admission, the neurological examination showed drowsy conscious level, cerebellar sign dominant on the left side, and left hemifacial spasm. CT scans disclosed a large hematoma in the left cerebellar hemisphere. An angiography revealed a dominant left PICA, but showed neither vascular malformation nor aneurysm. An emergency removal of the hematoma was carried out by using suboccipital craniectomy. Three days after the surgery, the patient's left hemifacial spasm disappeared completely. She had never suffered from left hemifacial spasm prior to this cerebellar bleeding. The hemifacial spasm was thought to be due to either the compression of the left facial nerve by the PICA which had been displaced by the cerebellar hematoma, or to the fact that the nucleus of the left facial nerve might have been stimulated by the hematoma, and the hemifacial spasm might have been caused as a result of the stimulation. The total removal of the hematoma and the postoperative CSF leakage might have decompressed the facial nerve. It was considered that this might be similar to microvascular decompression.

Cerebellar Diseases

[Cerebellar infarcts that require differentiation from tumors: diagnosis with MRI].

It is often difficult to differentiate cerebellar infarct with cerebellar swelling from neoplastic disorders, because former can be shown as cerebellar mass with marked contrast enhancement on CT scan. We analyzed radiologically three cases with cerebellar infarction by using MRI, conventional CT scan and angiography. Two cases in the acute stage could be diagnosed as cerebellar infarction by MRI alone based on the following findings: 1) the lesion was distributed in the territory of cerebellar arteries; 2) the normal pattern of cerebellar folia and fissures was preserved in Gd enhancement MRI image; 3) characteristics of MRI intensity were compatible with hemorrhagic infarction. The other case in the chronic stage showed peculiar enhancement, which was unusual for infarction. It was diagnosed as cellular infarction with reference to the angiographic findings. MRI is generally useful to obtain early diagnosis of tumor-like cerebellar infarcts, and proper treatment should be started as early as possible.

Aged

Transient presence of GABA in astrocytes of the developing optic nerve.

Immunostaining and high-pressure liquid chromatography (HPLC) were used to study the developmental time course of astrocytic gamma-aminobutyric acid (GABA) expression in rat optic nerve. GABA immunostaining was carried out on cultured astrocytes, and on whole optic nerve. Confocal scanning laser microscopy was used to obtain optical sections in excised whole tissue in order to localize the cellular origins of GABA within the relatively intact optic nerve. GABA immunoreactivity was localized in astrocytes identified by GFAP staining; GABA staining was most intense in early neonatal optic nerve and attenuated over 3 weeks of postnatal development. The staining was pronounced in the astrocyte cell bodies and processes but not in the nucleus. There was a paucity of GABA immunoreactivity by postnatal day 20, both in culture and in whole optic nerve. A biochemical assay for optic nerve GABA using HPLC indicated a relatively high concentration of GABA in the neonate, which rapidly attenuated over the first 3 postnatal weeks. Immunoreactivity for the GABA synthesis enzyme glutamic acid decarboxylase (GAD) was pronounced in neonates but also attenuated with development. These results indicate that GABA and the GABA synthesis enzyme GAD are localized in astrocytes of optic nerve, and that their expression is transient during postnatal development.

Animals

Evidence for coupling of Clostridium perfringens alpha-toxin-induced hemolysis to stimulated phosphatidic acid formation in rabbit erythrocytes.

When rabbit erythrocytes were exposed to low concentrations of Clostridium perfringens alpha-toxin, hot-cold hemolysis was observed. The toxin induced production of phosphatidic acid (PA) in a dose-dependent manner when incubated with erythrocytes at 37 degrees C. When erythrocyte membranes were incubated with the toxin and [gamma-32P]ATP in the presence or absence of ethanol, [32P]PA formation was maximal within 30 s, then sharply decreased, and began again after 5 min of incubation. Ethanol had no effect on the early appearance (at approximately 5 min) of PA formation induced by the toxin but significantly inhibited formation of PA over 10 min of incubation. Treatment of erythrocyte membranes with alpha-toxin resulted in the biphasic formation of 1,2-diacylglycerol and PA as well as an increase of inositol-1,4,5-trisphosphate (IP3) and decrease of phosphatidylinositol-4,5-bisphosphate (PIP2) within 30 s. Neomycin inhibited the toxin-induced increase in turbidity of egg yolk suspensions but did not inhibit the toxin-induced hemolysis of intact erythrocytes. On the other hand, neomycin inhibited the toxin-induced hemolysis of saponin-treated erythrocytes. In addition, neomycin inhibited PA formation induced by the toxin in erythrocyte membranes. IP3 was released by incubation of PIP2 with erythrocyte membranes but not by incubation of PIP2 with the toxin. The toxin stimulated the membrane-induced release of IP3 from PIP2. These data suggest that the toxin-induced hemolysis is dependent on the action of phospholipase C in erythrocyte membranes.

Animals

[A case of parenchymal pulmonary endometriosis with recurrent chest pain].

A 36-year-old woman was admitted to Nagasaki Citizens Hospital because of severe pleuritic chest pain associated with small amounts of hemoptysis. This episode occurred with the onset of her menses 2 months after a surgical abortion. Chest X-ray revealed a nodular shadow in the left middle lung field. ECG showed no abnormal findings. Pulmonary perfusion scintigram and arteriogram showed no evidence of pulmonary thromboembolism. Over the next 5 years she suffered 5 further episodes of chest pain without hemoptysis, in which every episode coincided with her menses and disappeared within several days after the end of the menses. Chest X-rays disclosed transient nodular shadows on 4 of 6 of the above mentioned episodes. In the earlier episodes one nodular shadow was noted in the left upper lobe S5 a. Later, it was accompanied by an additional nodular shadow in the S5b. Those shadows disappeared in accordance with the diminution of chest pain. From these findings the diagnosis of pulmonary endometriosis was confirmed. Consequently, the antigonadotropin danazol was administered for 6 months. After this, she had no recurrence of her symptoms. Catamenial hemoptysis is usually the most striking symptom of pulmonary endometriosis, which might be an important clue for its diagnosis. The case presented here was characterized by severe chest pain with paucity of hemoptysis.

Adult

The influence of implant design, application, and site on clinical performance and crestal bone: a multicenter, multidisciplinary clinical study. Dental Implant Clinical Research Group (Planning Committee).

This investigation is designed to provide scientific data that is directly relevant to the placement of dental implants. The study is concerned with the influence of implant design, application, and location on long-term clinical performance and crestal bone response over 5 years of function. It involves approximately 700 patients at 30 Veterans Administration Medical Centers from various geographic regions. Patients are being entered into the study over an 18-month period and monitored (post-loading) over 5 years. The participating centers were randomly assigned to one of two separate, independent study groups. Complications and adverse responses associated with the placement and use of the implants will be evaluated and all failures thoroughly documented. The experimental design and sample size are based on the primary hypothesis that an implant-supported prosthesis will be successful/functional over a 5-year period in at least 90 percent of the cases treated. Secondary hypotheses to be tested are (1) the success rate among implant designs are the same over a 5-year period; (2) the success rate among implant applications are the same over a 5-year period; (3) the success rate of individual implants are the same with regard to jaw location over a 5-year period; (4) the loss of crestal bone at the individual implant sites are the same among the implant designs over a 5-year period; and (5) the complications and adverse responses experienced with the different implant designs are the same over a 5-year period. The experimental design of this multicenter, multidisciplinary, randomized investigation is a cooperative effort of the Department of Veterans Affairs and several United States dental schools.

Alveolar Bone Loss

An evaluation of the Periotest system. Part II: Reliability and repeatability of instruments. Dental Implant Clinical Research Group (Planning Committee).

Investigators involved in a clinical study on dental implants being conducted by the Dental Implant Clinical Research Group participated in a two-part in vitro evaluation of the Periotest system. The first part involved each of 35 investigators taking three readings for each of 16 models designed to simulate an implant in place in the oral cavity and to cover most of the effective measuring range of the instrument. The second part, with which this article is concerned, was conducted by three study investigators to determine the level of agreement in readings for six different Periotest instruments. Readings were taken according to the manufacturer's instructions until two coincident readings were obtained. The readings were compared to evaluate inter- and intrainstrument reliability. Instrument repeatability was evaluated by examining the number of attempts required to obtain the two coincident readings. The Periotest system generally demonstrated a high degree of repeatability and reliability, with higher variability associated with specific model samples.

Dental Implants

Evaluation of the interprobe electronic periodontal probe.

The Interprobe is designed to provide measurements of pocket depths and attachment loss. Investigators involved in a clinical study on dental implants being conducted by the Dental Implant Clinical Research Group participated in an in vitro evaluation of the variability of repeated measurements made with the Interprobe. Measurements were made on holes drilled to predetermined depths in metal blocks. Three readings by investigators for each of nine test holes were in agreement 75.2 percent of the time. At least two of three readings were in agreement in 98.1 percent of the attempts. Either two of three or three of three readings were within 0.5 mm of the actual depth of the holes over 99 percent of the time. No correlation was noted for accuracy of measurements with hole depth or present clinical duties of the investigators. Although slight initial improvement in measurement accuracy was observed, it was not statistically significant in time over the three measurement sequence.

Analysis of Variance

Evaluation of hemodialysis efficiency by an edema fluid model.

The concentrations of urea, creatinine, and uric acid were measured in edema fluid and plasma during hemodialysis and 18 h after hemodialysis. The concentrations of these solutes in plasma were 15-17% lower than in the edema fluid after hemodialysis. Eighteen hours after hemodialysis, however, the concentrations in plasma were almost the same as those in edema fluid. These data suggest that the removal of these solutes from the extracellular space is delayed during hemodialysis. The plasma concentrations obtained at 18 h after hemodialysis are better indicators of hemodialysis efficiency.

Adult