Biomedical subjects

A Kojima

Publications and source records attributed to A Kojima.

At least 109 records · Page 6Linked to original sources

PubMed1998

Accidental transmission of HCV and treatment with interferon.

Accidental transmission of contagious pathogens, especially hepatitis C virus (HCV), by needlestick or other means as an occupational hazard for medical staff is of concern. We retrospectively analysed cases of work-related accidental injury with pathogens such as hepatitis B virus (HBV), HCV, syphilis and human immunodeficiency virus (HIV) reported to the centres for disease control at 15 hospitals (total 5776 beds) in the Gunma prefecture, Japan, from December 1990 to August 1993 (24.7 months). There were 416 such cases (16.8 cases/month), with an incidence of 0.2-3.5 accidents per month per hospital. Such accidents occurred in 297 (71.2%) nurses, 98 (23.5%) medical doctors, 13 (3%) laboratory technicians, four (1.0%) hospital maintenance workers, one (0.2%) assistant nurse, one secretary and two others. There were 323 (77.6%) injuries caused by needlestick, 42 (10.1%) from suture needles or surgical knife cuts, 17 (4.1%) from blood splatters from patients into the eyes or mouth, 10 (2.4%) from contact with injured skin and 24 (5.8%) simple skin contacts. Of the pathogens, 60.3% were HCV, 22.6% HBV, 5.8% syphilis, 0.7% HIV and 10.6% were of unknown origin. Four cases (1.6%) of HCV infection were found and treated with one or two courses of interferon therapy, and HCV was subsequently cleared. All four patients were cured with interferon therapy. None of the HBV-injured cases resulted in infection, possibly because of prophylaxis with HB immunoglobulin and HB vaccine. No HIV or syphilis infection was contracted. In summary, chronic HCV infection acquired as an occupational hazard can be cured by appropriate treatment, such as with interferon, after early detection of the infection.

Accidents, Occupational↗

PubMed1998

Inhibition of human immunodeficiency virus type 1 virion entry by dominant-negative Hck.

To study the role of Src family tyrosine kinases in infection with human immunodeficiency virus type 1 (HIV-1), we constructed an Hck mutant, HckN, that hinders signaling from wild-type Hck. HIV-1 produced in HckN-expressing cells was significantly less infectious to HeLa-CD4-LTR-beta-gal (MAGI) cells than HIV-1 produced in mock-transfected cells. The inhibitory effect of HckN was compensated for by the expression of vesicular stomatitis virus G protein. Finally, we found that the HIV-1 produced in the HckN-expressing cells entered into the cells less efficiently than did the control HIV-1. These results suggest that the Src family tyrosine kinases regulate entry of HIV-1 into target cells.

Gene Products, nef↗

PubMed1998

Adenovirus vector-mediated perforin expression driven by a glucocorticoid-inducible promoter inhibits tumor growth in vivo.

To evaluate the concept that in vivo transfer of perforin complementary DNA (cDNA) will suppress tumor growth, we constructed an adenovirus vector (AdGRE.PFP) carrying perforin cDNA driven by the glucocorticoid response element (GRE) promoter. We infected A549 lung carcinoma cells with this vector in vitro and in vivo, and evaluated cell growth over time. In the presence of dexamethasone, in vitro infection of A549 cells with the AdGRE.PFP vector yielded perforin messenger RNA (mRNA) transcripts and effectively suppressed A549 cell growth. In accord with these in vitro observations, administration of dexamethasone following direct injection of AdGRE. PFP into established subcutaneous A549 tumors in nude mice resulted in a marked reduction in tumor growth as compared with AdGRE.PFP infection without dexamethasone or with dexamethasone alone. These observations suggest that regulable, adenovirus-mediated gene expression of perforin cDNA may have potential as a strategy for local control of tumor cell growth.

Adenoviridae↗

PubMed1998

Production of recombinant porcine tumor necrosis factor alpha in a baculovirus expression system.

Porcine tumor necrosis factor alpha (TNF-alpha) was produced using a baculovirus system in Spodoptera frugiperda (SF21AE) cells. Cytotoxic activity was detected in supernatant of sonicated SF21AE cells infected with recombinant viruses. The recombinant protein was also demonstrated to be functionally active by its ability to cause apoptosis in Wehi 164 cells. Three distinct bands of 26, 17 and 14 kDa were revealed by Western blot analysis using anti-human TNF-alpha antibody. Moreover, the anti-human TNF-alpha antiserum significantly neutralized the cytotoxic activity of the supernatant of sonicated SF21AE cells infected with recombinant viruses.

Animals↗

PubMed1998

Compensatory excretion of prostacyclin and thromboxane metabolites in obstructive sleep apnea syndrome.

Since obstructive sleep apnea syndrome (OSAS) is often linked with systemic hypertension, we sought to clarify the characteristics of prostanoid metabolism in OSAS. In 7 OSAS patients (apnea-hypopnea index, 51.0 +/- 23.4) and 7 non-snorers as control, nocturnal urine was sampled and analyzed for stable metabolites of prostacyclin (PGI2) and thromboxane A2 (TxA2), [6-keto-PGF1alpha and thromboxane B2 (TxB2)]. The ratio of 6-keto-PGF1alpha to TxB2 was significantly higher in OSAS (2.97 +/- 1.52) than in control (1.38 +/- 0.38). Successful treatment with nasal continuous positive airway pressure (8.3 +/- 1.5 cmH2O) for 3 days caused a significant decrease in mean blood pressure in OSAS. Moreover, the 6-keto-PGF1alpha to TxB2 ratio also significantly decreased to 1.74 +/- 0.58, a level which may not significantly different from control. These results suggest that the production ratio of PGI2 to TxA2 is shifted toward vasodilatation in untreated OSAS. We conclude that the production of prostanoids plays a role in compensating for the systemic hypertension in OSAS.

6-Ketoprostaglandin F1 alpha↗

PubMed1998

[Results of anatomical segmentectomy for lung cancers].

Anatomical resections of the segment, so called 'anatomical segmentectomy', involving a small-sized lung cancer performed in 55 compromised cases in our hospital since 1985. On the operation we separated the intersegmental plane not with the traditional digital dissection but with meticulous electrocautery following the intersegmental pulmonary venous structure from hilal towards the peripheral area. Forty-six cases were primary lung cancers and 9 were metastatic ones. In 7 cases cancer residue was confirmed, especially on the intersegmental plane in one case and on the bronchial stump in another one. In 35 cases of primary non-small cell lung cancer (NSLC), recurrences in the separated plane or other segment of the same lobe appeared later in 2 cases, however there was no locoregional recurrence in cases with tumorous diameter less than 30 mm. The prognosis of 29 cases of NSLC with p-stage I is excellent because those 5 year survival rate is very high, 87.1%. The mean loss of ventilatory functions after segmentectomy was approximately half that of lobectomy. According to these results, we conclude that the anatomical segmentectomy is useful to the limited resection for small-sized NSLC with stage I.

Adenocarcinoma↗

PubMed1998

[A case of bronchial mucoepidermoid carcinoma treated with right sleeve middle lobectomy].

We reported one case of a 26-year-old woman in whom mucoepidermoid carcinoma of the right middle lobe bronchus was successfully treated by bronchoplasty. The patient complaining fever and cough was admitted to our hospital and the bronchoscopic examination revealed a tumor mass occluding the right middle lobe bronchus. Thus, sleeve middle lobectomy was performed. The histological examination of the resected material revealed a low-grade malignant mucoepidermoid carcinoma with no lymphatic metastasis. The patient has been well and free of recurrence for one year postoperatively. In this case, sleeve lobectomy is approved of an effective method for local curability and preservation of respiratory function.

Adult↗

PubMed1998

[Types and dimensions of mineral fibers in the atmosphere and from lungs of residents in the urban area].

OBJECTIVE: The objective of this study was to estimate the types and origin of the mineral fibers in the lungs of residents in the urban area. METHODS: Mineral fibers in the atmosphere from 21 urban areas were analyzed by direct transfer-analytical transmission electron microscopy (ATEM). Lung tissues of 36 urban residents without occupational asbestos exposure were also analyzed by ATEM after low temperature ashing. Measurement of dimensions of all types of mineral fibers, identification of asbestos, and classification of nonasbestos fibers according to the combination of main elements were carried out. RESULTS: 1. Chrysotile, amosite, actinolite, tremolite and 11 types of nonasbestos fibers were found in both the lung tissues and the atmospheric samples. The fibers, mainly composed of Al and Si, contributed 16.3% and 62.3% of the atmospheric samples and lung tissues respectively. On the other hand, the proportion of the fibers mainly composed of S and Ca were 43.7% and 0.0% in the atmosphere and lung tissues respectively. Those fibers mainly composed of P and Fe were 0.4% and 18.4% in the atmosphere and lung tissues respectively. 2. Fifteen types of nonasbestos fibers were found exclusively in the atmosphere. The average proportions for ten of these were less than 0.5% each. 3. Crocidolite was found exclusively in the lung tissues. 4. No significant difference in the geometric mean of length and diameter of asbestos was found between the atmospheric samples and lung tissues. Some types of nonasbestos fibers had significantly larger length and diameter in the atmospheres than in the lung tissues (p < 0.01). CONCLUSION: The results suggest that mineral fibers found in lung tissues could be classified into three groups on the basis of their behavior. 1) Some fibers, such as amphibole asbestos and fibers composed of Al and Si, are inhaled from the atmosphere and remain in the lung tissues for a long time. 2) Some fibers, such as those composed of S and Ca, are inhaled from the atmosphere and eliminated from the lung tissues within a relatively short time. 3) Some fibers found more in the lung tissues than in the atmospheres, such as those composed of P and Fe, are suspected to be generated in the lungs.

Air Pollutants↗

PubMed1997

Generation of neutralizing antibody to the reverse transcriptase of human immunodeficiency virus type 1 by immunizing of mice with an infectious vaccinia virus recombinant.

Antibodies inhibiting the reverse transcriptase (RT) of human immunodeficiency virus type-1 (HIV-1) were found to be generated in the serum of mice repeatedly infected with a vaccinia virus recombinant, WRRT, expressing the enzyme. A monoclonal antibody (mAb), 7C4, which specifically and almost completely inhibits the RNA-dependent DNA polymerase activity of HIV-1 RT was produced from a mouse repeatedly immunized with WRRT. 7C4 seems to be specific for HIV-1 among retroviruses: 7C4 inhibited RT activity of three strains of HIV-1 (IIIB, Bru, and IMS-1) but not of two strains of HIV-2 (GH-1 and LAV-2) or two strains of SIV (MAC and MND). The immunoglobulin isotype of three out of four mAbs produced from spleen cells of the immunized mouse were IgG2a. This immunization method that avoids protein denaturation may preferentially induce a T helper type-1 immune response and increase the chances of producing the only occasionally obtainable mAb capable of recognizing a conformational epitope and completely inhibiting enzyme activity.

Animals↗

PubMed1997

Detection of Mycoplasma in avian live virus vaccines by polymerase chain reaction.

The polymerase chain reaction (PCR) was evaluated to detect mycoplasma contamination of avian live virus vaccines. The specificity of the primers showed that 34 strains belonging to nine species of avian mycoplasma DNA could be detected. The sensitivity of PCR to detect mycoplasma DNA was 10(0.2) colony forming units (cfu) of Mycoplasma synoviae and 10(0.7) cfu of Mycoplasma gallisepticum. When M. synoviae and M. gallisepticum were spiked into several avian live virus vaccines, PCR gave a positive reaction except for the avian pox and the avian encephalomyelitis vaccines which were prepared from organ homogenates. Short-term incubation of avian encephalomyelitis vaccines improved the sensitivity of PCR to detect both M. synoviae and M. gallisepticum. Therefore, PCR, combined with the short-term incubation, were shown to be most effective in detecting mycoplasma contamination in all of avian live virus vaccines.

Animals↗

PubMed1997

Analysis of canine herpesvirus gB, gC and gD expressed by a recombinant vaccinia virus.

The genes encoding the canine herpesvirus (CHV) glycoprotein B (gB), gC and gD homologues have been reported already. However, products of these genes have not been identified yet. Previously, we have identified three CHV glycoproteins, gp 145/112, gp80 and gp47 using a panel of monoclonal antibodies (MAbs). To determine which CHV glycoprotein corresponds to gB, gC or gD, the putative genes of gB, gC, and gD of CHV were inserted into the thymidine kinase gene of vaccinia virus LC16mO strain under the control of the early-late promoter for the vaccinia virus 7.5-kilodalton polypeptide. We demonstrated here that gp145/112, gp80 and gp47 were the translation products of the CHV gB, gC and gD genes, respectively. The antigenic authenticity of recombinant gB, gC and gD were confirmed by a panel of MAbs specific for each glycoprotein produced in CHV-infected cells. Immunization of mice with these recombinants produced high titers of neutralizing antibodies against CHV. These results suggest that recombinant vaccinia viruses expressing CHV gB, gC and gD may be useful to develop a vaccine to control CHV infection.

Animals↗

PubMed1997

Prediction of effect of interferon on chronic hepatitis C.

Clinical, pathological, and virological analysis including hypervariable region-1 of hepatitis C virus (HCV) was performed to predict the effect of interferon (IFN) on 41 patients with chronic hepatitis type C. The low virus load, low frequency of the mutation in the hypervariable region-1 as the change of amino acid and high level of serum aminotransferase make one estimate the good effect of IFN on patients with HCV. Mutation in the hypervariable region-1 of HCV measured by fast assay fluorescence single-stranded conformational polymorphism was more frequent in nonresponders to IFN than responders. The most frequently mutated position was amino acid number 406. This indicates that the specific mutation site might affect the response of IFN.

Amino Acid Sequence↗

PubMed1997

Cervical spondylosis in paraplegic patients and analysis of the wheelchair driving action: a preliminary communication.

We investigated cervical spondylotic changes in paraplegic patients by examining the radiographs of their cervical spine. The incidence of cervical spondylosis in these patients was significantly higher than was found in normal control subjects of a matching age. We attributed this finding to the mechanical stress on the cervical spine during wheelchair driving. We then performed a biomechanical analysis using electromyography and goniometer. Paraplegic patients frequently flexed and extended their cervical spine shown by the goniometer, whilst the normal control subjects walked almost without moving their cervical spine. However, the integrated electron myography (IEMG) of the paraplegic patients was not synchronously increased with the integration of goniometer (IGOM) and the IEMG of the normal controls was significantly larger than that found in paraplegic patients on increasing their speed. This was thought to be necessary for steadying the head whilst walking or running.

Adult↗

PubMed1997

Enhanced expression of angiotensin-converting enzyme is associated with progression of coronary atherosclerosis in humans.

BACKGROUND: The clinical usefulness of angiotensin converting enzyme (ACE) inhibitors in preventing the recurrence of myocardial infarction has been investigated in large randomized trials. Results from many studies using animal models have suggested that ACE inhibitors have vasculoprotective effects, which may contribute to the prevention of coronary atherosclerosis. OBJECTIVE: To examine the association between vascular angiotensin generation and the development of coronary atherosclerosis in humans. METHODS: We used immunocytochemical techniques to examine frozen sections from 44 coronary artery segments from 19 corpses. RESULTS: Three segments were sites of plaque rupture in patients who had died from acute myocardial infarction. Other specimens of coronary artery segments were characterized histologically to be normal artery segments with diffuse intimal thickening (n = 6), hypercellular lesions composed of smooth muscle cells with or without infiltration of macrophages (n = 11), atheromatous plaque (n = 12), and fibrosclerotic plaque (n = 12). In normal arteries with diffuse intimal thickening, ACE was expressed in endothelial cells. In those with hypercellular lesions and atheromatous plaques, however, enhanced ACE expression was found in macrophages and smooth muscle cells. In contrast, arteries with fibrosclerotic plaques exhibited little or no ACE expression within the plaque. All three ruptured plaques expressed ACE strongly in macrophages accumulated around the attenuated fibrous cap. CONCLUSION: The strong association of enhanced ACE expression with the histologic characteristics of plaques suggests that ACE in hypercellular lesions, atheromatous plaques, and ruptured plaques contributes greatly to the further progression of atherosclerosis via an increase in vascular angiotensin II formation and inactivation of bradykinin.

Adult↗

PubMed1997

Genetically determined thymus enlargement in the early life in BUF/Mna rats.

BUF/Mna (B) rat is a mutated strain, having much larger thymus than WKY/ NCrj (W), ACI/NMs (A), and F344 (F) rats throughout their life-span. Rats of the latter 3 strains have normal sized thymuses, being less than 5.3 in the thymus to body weight ratio (mg/g), when they were killed at 6 weeks of age. Genetic segregation of large thymus size in the B strain at 6 weeks of age was studied by crossing B rats with W, A or F rats. All of 3 types of the F1 hybrid rats between the B strain and the other strains showed intermediate thymus ratios between those of both parental strains. In F2 rats between the B and W strains, the distribution of thymus ratios showed about 5 different peaks. These findings might indicate that two polymeric autosomal loci, thymus enlargement-1 (Ten-1) and thymus enlargement-2 (Ten-2), can enlarge the thymus size in B rats. Histometrically, whole thymus and cortex areas of the B rats were 2-5 times larger than the W rats during 6-12 weeks of age, but medulla areas were slightly different between the strains, showing that larger thymuses in B rats were mainly due to the enlarged cortex areas.

Animals↗

PubMed1997

[Energy spectral analysis in a photopeak region of 201Hg X-rays for 201Tl imaging].

For thallium-201 (201Tl) imaging, a photopeak of X-ray region of mercury-201 (201Hg) around 70 keV is usually employed. In such a low energy region, scatter and attenuation in the body become serious problems for quantitative scintigraphic imaging. We measured energy spectra around 201Hg X-ray region by a 201Tl line source with scattering materials and a gamma camera, and analyzed them to investigate the amount of scattered photons in 201Tl imaging window. Furthermore, Monte Carlo calculations were performed to distinguish primary photons from scattered photons. The results of analysis of energy spectra showed that the 201Hg X-ray photopeak consists of four different X-rays and do not have a perfect Gaussian shape. It was also found that not only forward scatter but also much backward scatter are included in this region. These scattered photons were reduced by using an off-peak window moved toward the higher energy region. We conclude that the data obtained from the analysis of scattered photons in 201Tl imaging window are very useful to develop a new scatter correction method and evaluate the scatter rejection methods proposed.

Gamma Cameras↗

PubMed1997

[Detection of microemboli by transcranial Doppler sonography after carotid endarterectomy].

Transcranial Doppler sonography (TCD), a non-invasive monitoring technique, has potential for detecting microemboli caused by the extracranial internal carotid artery. Many previous reports have shown that TCD-detected microemboli may be a risk factor for stroke. The main purpose of this study is to verify whether microemboli cease after carotid endarterectomy (CEA). TCD monitoring was performed in 43 cases before and after CEA. TCD monitoring was carried out for an hour at the ipsilateral middle cerebral artery of each case using a 2-MHz pulse-wave transcranial Doppler device, and high intensity transient signals were counted as microemboli. Microemboli were detected preoperatively in 10 cases (23.3%). Microemboli were not detected in any case immediately after CEA, in either the subacute stage (from 14 to 21 days after CEA) or in the chronic stage (more than 3 months after CEA). In the acute stage (from 3 to 7 days after CEA), microemboli were detected in three cases (7.0%). The rate of TCD-detected microembolic was always significantly reduced after CEA. TCD monitoring can be helpful in assessing the effect of CEA for prevention of stroke by removing the suspected source of microemboli.

Aged↗

PubMed1997

[Scatter correction with an off-peak triple energy window method in thallium-201 imaging].

For scatter correction using the triple energy window (TEW) acquisition in 201Tl imaging, we propose an off-peak TEW (OFPTEW) method. This OFPTEW method employs a wide main energy window of 34 keV centered at 73 keV and two 5.1 keV sub-energy windows and uses the scatter correction factor of 0.55. To assess scatter correction using the OFPTEW method in 201Tl imaging, phantom studies for planar and SPECT imaging were performed and the data with the OFPTEW method were compared with those by the conventional TEW method using the trapezoidal formula with the 20% main energy window centered at 70 keV and two 4.9 keV sub-energy windows. The planar images corrected by both methods were visually similar. The OFPTEW method, however, estimated the true primary counts and the contrast value in the cold lesion accurately, while the conventional TEW method underestimated the primary counts by 30% and gave wrong contrast values. For the myocardial SPECT imaging, the short-axis images by both methods were very similar, but the images by the OFPTEW method had 1.46 times more counts than those corrected by the conventional TEW method. In conclusion, the OFPTEW method can correct scatter in 201Tl imaging accurately and increase the primary counts effectively compared with the conventional TEW method.

Phantoms, Imaging↗