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Biomedical subjects

K Doi

Publications and source records attributed to K Doi.

At least 721 records · Page 40Linked to original sources
PubMed1985

The determination of glial fibrillary acidic protein for the diagnosis and histogenetic study of central nervous system tumors: a study of 152 cases.

Glial fibrillary acidic protein (GFAP) was purified from human spinal cord and cerebral white matter. GFAP was localized by an immuno-peroxidase method in normal adult and fetal human brains, rat brains, and 152 central nervous system (CNS) tumors. GFAP was found in reactive and normal astrocytes, immature cells of fetal brain at the 18th to 21st gestational weeks, and normal rat astrocytes. This GFAP staining was quite specific for glial tumors, including astrocytomas, glioblastomas, astroblastomas, and ependymomas. GFAP-positive cells were also found in oligodendrogliomas and choroid plexus papillomas, and they were interpreted as being astroglial or ependymal differentiations. Stromal cells in cerebellar hemangioblastomas were negative. However, engulfed astrocytes were found at the periphery of such tumors and often adjacent to the proliferate blood vessels. In meningiomas, neurinomas, metastatic carcinomas, pituitary adenomas and other non-glial tumors, GFAP-positive cells were not identified.

Animals↗
PubMed1985

Sessile adenoma of the gallbladder. Reappraisal of its importance as a precancerous lesion.

Three hundred gallbladders from patients with cholelithiasis were examined under a dissection microscope. Sixteen (5%) were found to have what have been called sessile adenomas. They consisted of mixtures of hyperplastic lining epithelium and metaplastic mucous glands, and their interstitium often included smooth-muscle fibers. Small foci of moderately severe cellular atypism were present in 19% of the adenoma cases, but none had definitive evidence of malignancy. Carcinoembryonic antigen was demonstrated in hyperplastic lining epithelium with or without cellular atypism in 31% of the cases. Sessile adenomas most likely represent reactive overgrowth and therefore we prefer to term them hyperplastic polyps.

Adenoma↗
PubMed1985

Reconstruction of the thumb with a free wrap-around flap from the big toe and an iliac-bone graft.

Ten patients with an amputated thumb had reconstruction by a free wrap-around flap taken from the big toe, including the nail, and an iliac-bone graft as the core of the reconstruction. The long-term results showed that a better replica of the thumb was achieved. The results were quite satisfactory both cosmetically and functionally, but there were some new problems: resorption of the bone graft, bulging of the pulp, skin atrophy at the base of the thumb, and deformity of the nail in a few patients. Modifications of the flap design and of the shape of the bone graft eliminated these problems nearly entirely.

Adult↗
PubMed1985

[The choice of antibiotics for prophylaxis of postoperative infections in the field of orthopaedics. Clinical experience with cefoxitin].

The clinical effects of cefoxitin (CFX) were evaluated in the prophylaxis of postoperative infections in the field of orthopaedics. The clinical response was good in 46 out of 50 patients; an efficacy rate of 92%. Four patients (8%) who did not respond to CFX were suffering from infections due to Mycobacterium tuberculosis (1), suspected Pseudomonas aeruginosa (1), and infection of unknown organism (2). A review was also made of recent trends among clinically isolated bacterial strains and their susceptibility to antibiotics in the field of orthopaedics. CFX is recommended as an antibiotic of first choice for the prophylaxis of postoperative infections in the field of orthopaedics.

Adolescent↗
PubMed1984

Clinical and experimental studies of bone union in reimplantation of digits: a preliminary report on ischemic interval.

The relationship between ischemic interval and bone union in reimplantation of digits was studied clinically and experimentally. In 32 reimplanted digits, the cases in which the bone union delayed had a longer ischemic interval. In experimental study of rats, bone union of the group of which ischemic interval was 12 hours was definitively delayed in comparison with that of the control group.

Adult↗
PubMed1984

Automatic milking apparatus for the insufficient venous drainage of the replanted digit.

An automatic milking apparatus composed of a finger attachment and a pump to push out the air was devised in order to perform the forced drainage from replanted digits with insufficient venous drainage. Seven replanted digits with insufficient venous drainage after replantation were applied, and remarkable improvement was found in five digits. An interesting case is reported in which a replanted digit without venous anastomosis survived as a consequence of applying the milking apparatus. The advantages of our milking apparatus are also discussed.

Amputation, Traumatic↗
PubMed1984

The free vascularized sural nerve graft.

The sural nerve was described as a new donor nerve of the free vascularized nerve graft in a fresh cadaver's dissection and in four clinical cases. The vascularized sural nerve is nourished by the cutaneous branch of the peroneal artery or the muscular perforating branch of the posterior tibial artery in our grafts. Compared to other vascularized nerve grafts, the sural nerve has many advantages: 1) A "two- or three-fold nerve graft" can be designed on itself without damage to the blood supply of the nerve, 2) survival of the nerve can be reasoned by the accompanying flap and the flap can close the skin defect simultaneously without additional vascular anastomosis, and 3) sensory loss at the donor site is negligible. The final extent of sensory recovery in our clinical cases could require several months, but a quickly advanced Tinel's sign suggested the technique's superiority.

Adult↗
PubMed1984

Alumina ceramic finger implants: a preliminary biomaterial and clinical evaluation.

An alumina ceramic hinge-type finger prosthesis, composed of alumina ceramics and high-density polyethylene, is described. Biomaterial evaluations, including flexion-extension tolerance, stretching, twisting, extraction tests, and histologic examinations of affinity for bone, demonstrated that this implant has characteristics superior to those of previous finger implants. Eighteen proximal interphalangeal joints and 13 metacarpophalangeal joints have been replaced with this alumina ceramic finger implant. Follow-up studies (12 to 31 months) have been most encouraging with satisfactory functional recovery and no fracture or dislocation of the implants.

Adult↗
PubMed1984

A comparison of physical image quality indices and observer performance in the radiographic detection of nylon beads.

Although various models have been proposed in an attempt to predict the usefulness of a radiographic image in terms of its physical characteristics, no previous work has shown whether a single physical image quality index, such as a signal-to-noise ratio, can reliably predict the performance of a human observer over a broad range of image characteristics. We studied the relationship between physical and visual image quality for the task of detecting nylon beads in radiographs. Thirty-seven imaging cases with different combinations of physical image characteristics were considered; these included variations in object size and magnification, X-ray beam quality, screen-film system, screen-film contact, film density and illumination, and viewing distance. For each imaging case, visual image quality was quantified in terms of observer performance in a 2AFC visual detection experiment. Physical image quality indices were calculated according to eight different models of the detection process; these indices combined data regarding object size and attenuation, screen-film system MTF, film gradient, noise Wiener spectrum, and visual system response. The results of this work indicate that, for the conditions studied, human observer detection performance most closely resembles that of a sub-optimal statistical decision process.

Form Perception↗
PubMed1984

Disseminated atypical mycobacteriosis.

Two cases of disseminated infection caused by Mycobacterium intracellulare were reported and discussed. In the first case, the patient was a fifty-seven-year-old male who complained of general fatigue, weight loss, and fever. Biopsy of the right inguinal lymph nodes and the liver revealed infiltration by histiocytes engulfing many acid-fast bacilli. At autopsy and egg-sized abscess was found is the region of the right iliac lymph nodes. Histological examination showed histiocytic infiltration in the abscess wall, neighboring lymph nodes, liver, and spleen. In the second case, the patient was a four-year-old boy, who had persistent fever and splenomegaly. Splenectomy was performed and histological examination of the spleen revealed multiple nodular infiltration by swollen histiocytes with many acid-fast bacilli in their cytoplasm. The bone marrow aspirates and liver tissue obtained in the necropsy also showed many histiocytes containing many acid-fast bacilli. The authors emphasized the importance of paying special attention to atypical mycobacteriosis in feverish patients having lesions with a proliferation of histiocytes.

Abscess↗
PubMed1984

Backscatter from metal surfaces in diagnostic radiology.

Backscatter from four commonly used metals (aluminum, lead, copper, and iron) was measured under diagnostic imaging conditions, using screen-film systems as detectors. The results indicate that for an 80-kV filtered beam and Par Speed/XRP system, backscatter increases as aluminum (Al) thickness increases until it reaches a plateau of approximately 12% at 50 mm Al. The amount of backscatter from any of these four metals increases as the tube voltage is raised from 60 to 115 kV. Measured backscatter depends strongly on the screens used, possibly due to their attenuation and energy response. Backscatter from aluminum was significantly greater than that from the other metals tested.

Aluminum↗
PubMed1984

Digital image processing: effect on detectability of simulated low-contrast radiographic patterns.

Detection studies of simulated low-contrast radiographic patterns were performed with a high-quality digital image processing system. The original images, prepared with conventional screen-film systems, were processed digitally to enhance contrast by a "windowing" technique. The detectability of simulated patterns was quantified in terms of the results of observer performance experiments by using the multiple-alternative forced-choice method. The processed images demonstrated a significant increase in observer detection performance over that for the original images. These results are related to the displayed and perceived signal-to-noise ratios derived from signal detection theory. The improvement in detectability is ascribed to a reduction in the relative magnitude of the human observer's "internal" noise after image processing. The measured dependence of threshold signal contrast on object size and noise level is accounted for by a statistical decision theory model that includes internal noise.

Computers↗
PubMed1984

Absolute speeds of screen-film systems and their absorbed-energy constants.

Absolute speeds (mR-1) of screen-film systems were determined accurately and precisely from ten independent measurements over a six month period at several beam qualities that included both scatter and scatter-free conditions. The absorbed x-ray energies in the screens that yielded a net film density of 1.0 were obtained by means of Monte Carlo calculations and a semianalytical method. The standard deviations of the calculated absorbed x-ray energies at different beam qualities were less than 10% for all of the screen-film systems studied. Therefore, the absorbed x-ray energy that produces a given film density for these systems can be regarded as constant at the beam qualities used. Quantum absorption and fractional energy absorption of the screens were also calculated. The predicted Wiener spectral values based on the number of photons detected were compared with the measured Wiener spectral values of the screen-film systems.

Radiographic Image Enhancement↗