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Biomedical subjects

A Kano

Publications and source records attributed to A Kano.

At least 19 recordsLinked to original sources
PubMed1997

Analysis of IFN-gamma-induced cell cycle arrest and cell death in hepatocytes.

The mechanism by which IFN-gamma induces cell cycle arrest and cell death in primary cultured hepatocytes was examined. The cell death exhibits apoptotic characters such as the appearance of apoptotic bodies and DNA fragmentation. IFN-gamma induced cell cycle arrest at the initial stage, followed by cell death. A protein synthesis inhibitor, cycloheximide, significantly inhibited cell death, implying that IFN-gamma induces de novo proteins involved in the death of hepatocytes. One of the most important apoptosis-related proteins, p53, was induced by IFN-gamma in hepatocytes in a dose- and time-dependent manner. Northern blot analysis demonstrated that IFN-gamma enhanced p53 mRNA expression as well as p21(WAF1/Cip1/Sdi1) mRNA expression, which is mediated by the increased expression of the p53 protein. Interestingly, IFN-gamma also induced cell death in p53-deficient hepatocytes. The cell death occurred rather earlier in p53-deficient cells than in normal hepatocytes. However, the cell death was not accompanied by apoptotic bodies. Therefore, IFN-gamma-induced hepatocyte cell death is p53-independent, and p53 may contribute to the apoptotic characters. In conclusion, IFN-gamma is supposed to cause cell cycle arrest by inducing p53 and p21(WAF1/Cip1/Sdi1), and it was demonstrated that IFN-gamma induces p53-independent cell death in primary cultured hepatocytes.

Animals↗
PubMed1996

Benign cementoblastoma. Case report.

Benign cementoblastoma is a rare benign odontogenic tumour of mesenchymal origin. A case of a 24-year-old man with benign cementoblastoma is presented. The lesion manifested as a round, radiopaque mass attached to the root of the left first molar of the mandible. The tooth was extracted and the lesion was removed. A diagnosis of benign cementoblastoma was made microscopically. There has been no evidence of recurrence during the three-year follow-up period. A review of the literature and a discussion of the histologic features of this case are included.

Adult↗
PubMed1995

Alternations in atrial natriuretic peptide release after DC cardioversion of non-valvular chronic atrial fibrillation.

The response of atrial natriuretic peptide (ANP) release to haemodynamic influences after cardioversion of atrial fibrillation has not been fully examined. We measured plasma concentrations of ANP and assessed haemodynamic changes 60-120 min after DC cardioversion in 22 patients with non-valvular chronic atrial fibrillation. Passive leg elevation to enhance volume expansion was performed 60 min after DC cardioversion. Sinus rhythm was restored in 18 of the 22 patients (successful DC cardioversion group). The control group consisted of seven patients with non-valvular chronic atrial fibrillation who did not undergo DC cardioversion (atrial fibrillation control group). In the successful DC cardioversion group, the mean pulmonary artery wedge pressure decreased significantly 15 min after cardioversion (P < 0.05) and then remained unchanged. Plasma concentrations of ANP also decreased significantly 15 min after cardioversion (P < 0.05). Furthermore, there was an additional significant decrease in ANP levels for up to 60 min after cardioversion (P < 0.05 from 15 min). Passive leg elevation for 15 min led to an increase in the mean pulmonary artery wedge pressure (P < 0.01) and right atrial pressure (P < 0.05), but did not result in increased plasma concentrations of ANP (47.1 +/- 27.6 vs 43.9 +/- 34.4 pg.ml-1, mean +/- SD, P = ns). In the atrial fibrillation control group, passive leg elevation increased the mean pulmonary artery wedge pressure (P < 0.01), the mean right atrial pressure (P < 0.05) and plasma concentrations of ANP (139.9 +/- 85.8 vs 168.1 +/- 108.2, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Effects of ventilation and pleural effusion on measurements of airway thermal volume and blood flow in dog lungs.

We studied the effects of ventilation and pleural effusion on measurements of airway thermal volume (ATV) and pulmonary blood flow (PBF) by using the airway gas thermometry method of V. B. Serikov, M. S. Rumm, K. Kambara, M. I. Bootomo, A. R. Osmack, and N. C. Staub (J. Appl. Physiol. 72: 944-953, 1992) in 39 anesthetized dogs with or without lung edema or pleural effusion. To examine the differential effects of increased-pressure and increased-permeability lung edema on accuracy and sensitivity of ATV and PBF, two models of lung edema were induced by intravenous infusion of a Dextran 70 solution and alloxan monohydrate, respectively. Dogs were hyperventilated for 3 min by using a wide range of minute ventilation (VE) to produce two steady-state conditions of airway temperature. Higher levels of VE increased an estimated amount of ATV. The ATV produced by hyperventilation at VE values of 559, 158, and 72 ml.min-1.kg-1 was consistent with the gravimetric total lung mass, the blood-free wet lung weight, and the extravascular lung water volume, respectively. The coefficient of lung thermal conductivity, a practical index of the rate of heat conduction through tissue from lung vessels, was related to the ratio of the decrease in expired air temperature to VE, and estimated PBF was consistent with the thermodilution cardiac output. Pleural effusion had little effect on measurements of ATV and PBF. However, ATV and PBF showed increased variation in dogs with dextran-induced lung edema.

Air Pressure↗
PubMed1994

Development of a digital duplication system for portable chest radiographs.

To provide high-quality duplicate chest images for the intensive care units, we have developed a digital duplication system in which film digitization is performed in conjunction with nonlinear density correction, contrast adjustment, and unsharp mask filtering. This system provides consistent image densities over a wide exposure range and enhancement of structures in the mediastinum and upper abdominal areas, improving visibility of catheters and tubes. The image quality is often superior to that of the original radiograph and is more consistent from day to day. Repeat rates for portable chest radiographs have been reduced by more than a factor of two since implementation of digitization in December 1991, and the number of repeat examinations caused by exposure errors have been substantially reduced.

Computer Systems↗
PubMed1994

Digital image subtraction of temporally sequential chest images for detection of interval change.

An automated digital image subtraction technique for temporally sequential chest images has been developed in order to aid radiologists in the detection of interval changes. A number of small regions of interest (ROIs) are selected automatically in the lung areas of two temporally sequential chest images. A local matching, based on a cross-correlation method, is performed on each pair of corresponding ROIs in order to determine shift values for the coordinates of two images. A proper warping of x,y coordinates is obtained by fitting two-dimensional polynomials to the distributions of shift values. One of the images is warped and then subtracted from the other. Forty six pairs of chest images (42 with interval changes and 4 without interval change) were processed using this method. The subtraction images were able to enhance various important interval changes, such as differences in the size of tumor masses, changes in heart size, and changes in pulmonary infiltrates or pleural effusions. Approximately 70% of the pairs showed reasonably good registration.

Humans↗
PubMed1994

[A case of gastric cancer completely responding to sequential methotrexate and 5-fluorouracil therapy].

A case of an 81-year-old male with Borrmann II type was reported. The lesion was diagnosed histologically as undifferentiated adenocarcinoma. Biochemically modulated chemotherapy preceded by administration of Methotrexate (MTX) and followed by 5-fluorouracil (5-FU) was given to him. The procedure was weekly intermediate-dose therapy consisting of MTX 100 mg (i.v.) followed 3 hours later by 5-FU 600 mg (i.v.) with leucovorin rescue in the following 2 days. After this treatment was repeated 6 times, advanced gastric cancer disappeared on endoscopic and histological findings, so the patient was regarded as showing a complete response. Ths, this biochemically modulated chemotherapy was thought to be in effective method against gastric cancer.

Adenocarcinoma↗
PubMed1993

[Evaluation of the potential benefit of computer-aided diagnosis (CAD) for lung cancer screenings using photofluorography: analysis of an observer study].

To evaluate the potential benefit of computer-aided diagnosis (CAD) in lung cancer screenings using photofluorographic films, we performed an observer test with 12 radiologists. We used 60 photofluorographic films obtained from a lung cancer screening program in Yamaguchi Prefecture (30 contained cancerous nodules and 30 had no nodules). In these cases, our current automated detection scheme achieved a sensitivity of 80%, but yielded an average of 11 false-positives per image. The observer study consisted of three viewing conditions: 1) only the original image (single reading), 2) the original image and computer output obtained from the current CAD scheme (CAD 1), 3) the original image and computer output obtained from a simulated improved CAD scheme with the same 80% true-positive rate, but with an average of one false-positive per image (CAD 2). Compared with double reading using independent interpretations, which is based on a higher score between two single readings, CAD 2 was more sensitive in subtle cases. The specificity of CAD was superior to that of double reading. Although CAD 1 (Az = 0.805) was inferior to double reading (Az = 0.837) in terms of the ROC curve, CAD 2 (Az = 0.872) significantly improved the ROC curve and also significantly reduced observation time (p < 0.05). If the number of false positives can be reduced, computer-aided diagnosis may play an important role in lung cancer screening programs.

Humans↗
PubMed1993

Unassigned or nonsense codons in Micrococcus luteus.

We previously reported that in Micrococcus luteus, a Gram-positive eubacterium with high genomic G + C content, certain codons ending with A did not appear in coding frames, including termination sites, and tRNAs that translate these codons were not detected. These facts suggest that at least some of them are unassigned (nonsense) codons, i.e. not assigned to any amino acid or to any stop signal. We have investigated whether AGA and AUA, universal Arg and Ile codons, respectively, are really unassigned codons by using a cell-free extract prepared from M. luteus and synthetic messenger RNAs. Translation of synthetic mRNA containing in-frame AGA codons does not result in "read-through" to codons beyond the AGA codons, i.e. translation ceases at codon AGA. Essentially the same result was obtained with mRNA containing AUA in-frame. A sucrose-gradient centrifugation profile of the reaction mixture has shown that practically all of the peptides that have been synthesized are attached to 70 S ribosomes. When in-frame AGA or AUA codons are replaced by UGA codons in mRNA, no read-through occurs beyond UGA, just as in the case of AGA or AUA. However, the synthesized peptide is released from the 70 S ribosomes. These data suggest that AGA and AUA are unassigned codons and differ from UGA in that they are not used for termination.

Adenine Nucleotides↗
PubMed1993

Computer-aided diagnosis in chest radiography. Preliminary experience.

RATIONALE AND OBJECTIVES: Computer-aided diagnosis (CAD) schemes for chest radiography are being developed with which to alert radiologists to possible lesions, and thus potentially improve diagnostic accuracy. However, CAD schemes have not been tested on a large number of clinical cases. The authors identify design parameters that would be required for development of an intelligent workstation. METHODS: Computer-aided diagnosis programs were applied for the automated detection of lung nodules, cardiomegaly, and interstitial infiltrates to 310 consecutive chest radiographs, and were analyzed for potential usefulness and limitations. Computer-aided diagnosis output was evaluated by radiologists and physicists for accuracy and technical problems, respectively. RESULTS: Approximately 70% of the results were judged to be potentially acceptable; however, the number of false-positive findings was relatively high. Technical problems included failure to detect subtle abnormalities and the occurrence of false-positive detections caused by normal anatomical structures. CONCLUSION: Computer-aided diagnosis has the potential to be a valuable aid to radiologists in clinical practice, if certain technical problems can be overcome and if optimal operating points can be defined for clinical use.

Adult↗
PubMed1993

Clinical experience with an advanced laser digitizer for cost-effective digital radiography.

Film digitization has not been widely pursued in clinical settings mainly because of perceived limitations involving film latitude and image quality. However, a high-quality laser digitizer can be combined with wide-latitude film and specially developed digital processing techniques to achieve image quality comparable or superior to that of storage phosphor computed radiography (SPR) over a wide range of exposure. This film digitization system provides the operational advantages of digital radiography, such as consistent image density, high-quality inexpensive duplicates, and digital storage and retrieval capability. The reliability and monetary costs of the system also compare favorably with those of SPR. In the long term, technologies that employ reusable plates and do not require chemical processing to produce diagnostic images may well replace screen-film systems. Presently, however, film digitization remains a practical and cost-effective approach to digital radiography.

Cost-Benefit Analysis↗
PubMed1993

Effects of acetylsalicylic acid on pulmonary vascular tone and membrane permeability in blood-perfused dog lung.

We studied the effects of acetylsalicylic acid (ASA) on pressor response, microvascular filtration coefficient (Kf), extravascular lung water, and plasma concentrations of cyclooxygenase- and 5-lipoxygenase-derived products in 21 blood-perfused dog lungs with constant flow. The lungs were perfused for 1 h with an intrapulmonary injection of saline as vehicle (n = 5), a low dose of ASA [136 +/- 25 (SD) micrograms/ml perfusate; n = 5], a high dose of ASA (1,006 +/- 278 micrograms/ml perfusate; n = 6), or alloxan (1,000 mg; n = 5). Alloxan significantly increased Kf and extravascular lung water, whereas neither the low nor high dose of ASA increased Kf or extravascular lung water. The ASA-induced increase in vascular resistance did not correlate with the extent of the decrease in perfusate 6-keto-prostaglandin F1 alpha or the ratio of perfusate 6-ketoprostaglandin F1 alpha to thromboxane B2. Moreover, ASA did not enhance the generation of perfusate leukotrienes B4, D4, or E4. We conclude that pulmonary microvascular permeability is unaltered by ASA and that neither the decrease in plasma prostacyclin nor the increase in plasma sulfidopeptide leukotrienes may account for ASA-induced pulmonary vasoconstriction.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

[Urease test].

In order to elucidate bacterial infection, as a rule, isolated and cultured bacteria of a specimen are identified by their morphologies or biochemical characteristics. However, the culture of Helicobacter pylori (H. pylori) is difficult and takes, much time. Therefore, favorable test results are currently obtained by combining the culture method, histopathologic method, urease test and sero-immunologic test. The merits of the urease test are that judgement is available immediately after endoscopy and that the test is inexpensive. The demerits are that the existence of H. pylori is diagnosed only by estimation that endoscopy is indispensable for the test. When compared with the culture method, the urease test has 91.8% sensitivity and 94.7% specificity and when compared with the histopathologic method, it has 94.4% sensitivity 88.4% specificity. In the future, the clinical requirement will increase for quick investigation on the evidence of H. pylori-induced infection. These results show that urease test is useful because it is simple and allows quick judgement.

Ammonia↗
PubMed1992

Image feature analysis of false-positive diagnoses produced by automated detection of lung nodules.

RATIONALE AND OBJECTIVES: To reduce the number of false-negative diagnoses by radiologists, the authors are developing a computer-aided diagnosis scheme for detection of lung nodules in digital chest images. In this study, the authors attempted to reduce the number of false-positive diagnoses obtained with a previous computer scheme by incorporating additional knowledge from experienced chest radiologists into the computer scheme. METHODS: The authors applied their previous computer scheme, using less-strict criteria, to 60 clinical chest radiographs; this yielded 735 candidate nodules (23 true nodules and 712 false-positive diagnoses). These candidates were analyzed using region-growing, trend-correction, and edge-gradient techniques to determine measures by which to quantify image features of candidate nodules. RESULTS: The 712 false-positive diagnoses represented various anatomic structures that were located throughout the chest image. From this analysis, we were able to decrease the number of false-positive errors from an average of 12 to approximately 5 per image without eliminating any true nodules. CONCLUSION: Our results show that incorporating knowledge from experienced chest radiologists into the computer algorithm will play an important role in the development of computerized schemes for the detection of pulmonary nodules.

Diagnostic Errors↗
PubMed1992

Predictors of relapse in peptic ulcer.

Four hundred and two patients with peptic ulcer were selected for acute therapy with either pirenzepine (100 mg/day) or cimetidine (800 mg/day) using the envelope method. Those who achieved healing within 3 months (251 patients) were randomized in a double-blind fashion to maintenance therapy with either pirenzepine (75 mg/day) or placebo. In a preliminary study of 163 patients in which a multiple regression life-table method was employed, 4 out of 15 possible predictors were found to have a significant influence on relapse. These were site of ulcer lesions, psychological stress, endoscopic findings at the time of healing of the original ulcers, and acute therapy. Stratified analysis of the evolution of relapse by the Cutler-Ederer life-table method indicated that several other factors also influenced relapse in certain patient subgroups. Most relapses (93.8%) occurred at the same site as, or close to the site of, the original ulcers, indicating that ulcer scars also play a role in relapse.

Adult↗
PubMed1991

Novel anticodon composition of transfer RNAs in Micrococcus luteus, a bacterium with a high genomic G + C content. Correlation with codon usage.

The number and relative amount of isoacceptor tRNAs for each amino acid in Micrococcus luteus, a Gram-positive bacterium with high genomic G + C content, have been determined by sequencing their anticodon loop and its adjacent regions and by selective labelling of tRNAs. Thirty-one tRNA species with 29 different anticodon sequences have been detected. All the tRNAs have G or C at the anticodon first position except for tRNA(ICGArg) and tRNA(NGASer), in response to the abundant usage of NNC and NNG codons. No tRNA with the anticodon UNN capable of translating codon NNA has been detected, in accordance with a very low or zero usage of NNA codons. The relative amount of isoacceptor tRNAs for an amino acid determined by selective labelling strongly correlates with usage of the corresponding codons. On the basis of these and other observations in this and other eubacterial species, we conclude that the relative amount and anticodon composition of isoacceptor tRNA species are flexible, and their changes are mainly adaptive phenomena that have been primarily affected by codon usage, which in turn is affected by directional mutation pressure.

Anticodon↗
PubMed1990

[An advanced gastric cancer with varied histopathologic features including a choriocarcinoma: report of a case].

A 77-year-old male, complaining of epigastralgia, was admitted to hospital. An upper GI series revealed a hemispheric filling defect at the greater curvature of the lower gastric body and two submucosal tumor-like lesions of the antrum. Closer inspection revealed a tumor measuring 60 x 42 mm, with an irregular ulcer, and two submucosal tumor-like lesions with bridging folds, measuring 42 x 28 mm and 20 x 14 mm, respectively. Histologically, the microscopic features in the ulcerated tumor showed a variety of tumor cells with clear PAS-positive cytoplasms and marked atypical nuclei forming glandular structures that predominated. Additionally, a clear cell carcinoma, a papillary adenocarcinoma, a signet-ring cell carcinoma, and a choriocarcinoma were partially seen. Finally, in the submucosal tumor-like lesions, diffuse small tumor cells with scanty PAS-positive cytoplasms without granular structures were seen.

Adenocarcinoma↗