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Biomedical subjects

K Kim

Publications and source records attributed to K Kim.

At least 613 records · Page 34Linked to original sources
PubMed1982

Site location and requirements for the installation of a nuclear magnetic resonance scanning unit.

The installation of a nuclear magnetic resonance unit in any diagnostic facility involves certain location and environmental requirements. Based on our experience with the FONAR QED 80 system, we have delineated the major factors which must be considered when planning for such an installation. The major requirements are location and space. Suggested layouts for the suite and the control room are included. Certain environmental specifications will vary depending on the location of the facility and the type of unit installed.

Air Conditioning↗
PubMed1982

Nuclear magnetic resonance imaging and evaluation of human breast tissue: preliminary clinical trials.

In vivo clinical evaluations of human mammary tissue, including normal, dysplastic, and neoplastic breasts, were initiated using the FONAR method of nuclear magnetic resonance (NMR) imaging. Spin-lattice relaxation times (T1) were determined and correlated with other diagnostic modalities including mammography, xeroradiography, and sonography. Normal breasts and breasts with extensive fatty replacement were found to have the lowest T1 values, whereas T1 values of malignant tissue were elevated. T1 values for mammary dysplasia extended over a wide range, and NMR images exhibited lower proton density than normal tissue. In several patients with severely dysplastic breasts, T1 values overlapped those from patients with documented breast neoplasms. Markedly elevated T1 values were obtained from fluid-filled cysts that were well beyond the range of malignancy.

Breast↗
PubMed1981

Naloxone effects on the blood pressure response induced by thin-fiber muscular afferents.

Naloxone effects on the blood pressure level and on the blood pressure responses induced by thin-fiber muscular afferent stimulation were studied in anesthetized, bilaterally vagotomized and carotid sinus nerve-denervated dogs under artificial ventilation. Repetitive pulses of 8 Hz with various intensities were applied to the gastrocnemius nerve for 1 min while monitoring the compound action potentials. The mean arterial pressure significantly (P less than 0.001) rose by 10.95 +/- 1.78 mmHg (mean +/- S.E.) about 5 min after a naloxone injection. Compared with the reflexive response in the control period, the depressor effect significantly decreased by 3.80 +/- 1.06 mmHg, and the pressor effect significantly increased by 3.63 +/- 0.73 mmHg for 30 min after the injection of naloxone. No correlation was found between naloxone effects on the blood pressure level and on the reflex response, indicating an involvement of different mechanisms with these naloxone effects. We suggest that endogenous opiates might participate in the regulation of the blood pressure level, as well as of the blood pressure responses caused by thin-fiber muscular afferents.

Afferent Pathways↗
PubMed1981

Basis of observed resistance of L1210 leukemia in mice: methotrexate, 6-thioguanine, 6-methylmercaptopurine riboside, 6-mercaptopurine, 5-fluorouracil, and 1-beta-D-arabinofuranosylcytosine administered in different combinations.

Schmid et al. (Cancer Treat. Rep., 60: 23-27, 1976) reported rapid emergence of resistance of L1210 leukemia cells in mice to two schedules of six antimetabolites and much slower development of resistance to a third schedule. Such rapid development of resistance to six drugs presents a striking puzzle, and one whose solution gives some insights into the basis for general emergence of drug resistance. Our approach was to examine the consequences of applying these drugs singly or in pairs and, from the results, to infer interactions in six-drug combinations. 6-Thioguanine (TG) and 6-mercaptopurine are the key drugs since, as shown by Schmid et al., resistance of leukemic cells appeared to six-drug combinations at the same time as did resistance to the purine analogs; sensitivity to the other drugs remained. We demonstrated that cells which emerged were resistant to both of the purine analogs, owing to a deficiency of the activating enzyme hypoxanthine-guanine phosphoribosyltransferase. TG resistance arose in the presence of TG because of an overgrowth of TG-resistance mutants that were present as one cell in 10(4) in the original L1210 population. L1210 cultures were prepared free of TG-resistant mutants. With these cells, TG administered shortly after inoculation was very effective in delaying their death. The cells that finally grew out were still TG sensitive. Simultaneous treatment with all the drugs greatly delayed appearance of TG resistance in vivo and in vitro. Methotrexate alone was responsible for this result, owing to its ability preferentially to kill TG-resistant cells. The other three drugs were not effective in delaying TG resistance. Methotrexate was effective only if it was added daily; one large injection was ineffective. Therefore, TG and methotrexate added daily for 6 days (simultaneous schedule) was the most effective drug regimen tested.

Animals↗
PubMed1980

A possible participation of endogenous opiates in respiratory reflexes induced by thin-fiber muscular afferents.

In anesthetized, vagotomized, paralyzed, and artificially ventilated dogs, naloxone effects on respiratory responses induced by thin-fiber muscular afferents were studied by recording phrenic nerve discharges. Naloxone augmented respiratory outputs, before, during, and after the stimulation. Two different types were found in the returning phase of the respiratory response by thin-fiber muscular afferent stimulation: respiratory outputs were supressed below the pre-stimulus level within several minutes after the cessation of the stimulus in some cases, while in the other cases they remained above the pre-stimulus level. In the latter cases, naloxone did not change the pattern of returning phase of the response, on the other hand, in the former cases, the after-suppression was significantly reduced by naloxone. The present results suggest that endogenous opiates play a role in setting the level of respiratory outputs and that in addition to facilitatory effects on respiration, thin-fiber muscular afferents drive a negative feedback system via neurohumoral mechanisms.

Afferent Pathways↗
PubMed1980

Hepatitis B virus and alcoholic liver damage in the Airin district. (Osaka's skid row area).

Healthy adults and non-liver disease patients in the Airin district gave a positivity rate for HBs antigen of approximately 2%, which is not so much different from the average of the entire Japanese population. In this district, the positive rate of HBs antigen 5% (11 out of 244) in chronic liver disease is much lower than that (31%) of control group patients at Osaka City University Hospital (O.C.U.H.). However the positive rate of anti-HBs antibody in this district is 46% which is extremely high compared with that (23.4%) in the rest of Japan. The positive for anti-HB antibodies (including of anti-HBs and anti-HBc antibody) accounted for 67% of non-liver disease patients and 68% of chronic liver disease patients in the Airin district. Corresponding values for patients at O.C.U.H. were 44% and 43% respectively. There were no significant differences in the histological picture between HBs antigen-negative patients with and those without demonstrable anti-HBs antibodies. Changes in the liver exhibited by heavy drinkers inhabitating the Airin district were primarily those of alcoholic liver damage.

Antibodies, Viral↗
PubMed1980

Cytologic screening for gynecologic cancer.

In the past 30 years there has been no improvement in the five-year survival rate for endometrial carcinoma. Any change comparable to improved survival in cervical carcinoma will be accomplished only by similar detection of the early asymptomatic and precursor lesions of endometrial carcinoma. Reasons why the conventional Pap smear taken today has only a 25% to 50% screening accuracy for endometrial carcinoma are explained along with methods to improve these percentages. With our technic, endometrial aspiration cytology has the capabilities of screening for varying stages of endometrial hyperplasia that are considered precursors of endometrial carcinoma, as well as an 85% accuracy rate for screening detection of established endometrial carcinoma. These technics and methods, along with accompanying photographs and photomicrographs of representative cytologic and histologic specimens of varying representative lesions are shown.

Adult↗
PubMed1980

Malfunction of a Björk-Shiley mitral valve prosthesis due to excessive platelet-fibrin deposition on its sewing cuff. A case report.

A Bjork-Shiley mitral valve prosthesis had to be replaced 4 years after implantation because of disc entrapment by an over-grown fibrous tissue on its sewing cuff. This abnormal fibrous tissue was found out to be an organizing platelet-fibrin deposit, of which luminal surface was only incompletely endothelialized. It is indicated that the heart valve prosthesis generally remains non-endothelialized for a prolonged period of time after implantation in man. Anticoagulation therapy should thus be given throughout the postoperative period for patients with the heart valve prosthesis.

Adult↗
PubMed1979

Theoretical study of hydration of RNA.

The hydration phenomena of A-RNA double helix and the anticodon loop of transfer RNA have been theoretically investigated using the empirical potential energy functions. The hydration schemes of a model compound of A-RNA and a polynucleotide which has the structure of the anticodon loop of yeast tRNAPhe have been determined, and their stabilization energies produced by the introduction of water in the first hydration shell were calculated by considering the hydrated ones as supermolecules. The results indicate that hydration scheme of A-RNA considerably differs from that of B-DNA and stabilization energy due to hydration of A-RNA is not so great as B-DNA. In the anticodon loop structure, however, stabilizing effect of the bound water molecules upon the structure is significant. From the results, the reason why the structure of RNA remains unchanged with the change of hydration degree while that of DNA is altered was studied.

Anticodon↗