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Biomedical subjects

H Kim

Publications and source records attributed to H Kim.

At least 1,171 records · Page 65Linked to original sources
PubMedDate not supplied

Effect of drug stability on the analysis of release data from controlled release microspheres.

The objective of this study was to determine the effect of drug stability on the analysis of in vitro release data from controlled release microspheres. Amoxicillin was chosen as a model drug and its stability in various media determined. The in vitro release of amoxicillin from PLGA microspheres was investigated in phosphate buffered saline (PBS) containing either Tween-80 or Tween-80 + Na-azide. Drug concentration in the media and the amount remaining inside the microspheres were analysed using HPLC. Amoxicillin degraded rapidly in PBS. The rate of degradation was reduced in the presence of Tween 80 and Na-azide. Drug release from the microspheres was analysed with and without considering the drug degradation rate. Mass balance between released drug, drug remaining in the microspheres and initial drug loading was only achieved when drug degradation was accounted for. Drug stability should be considered in analysis of in vitro extended release data, since released drug may degrade with time. These results have implications for in vitro release studies for controlled release products that include drugs and other compounds which are susceptible to degradation during the course of the release study.

Amoxicillin↗
PubMedDate not supplied

Fabrication and analysis of plastic hypodermic needles.

Plastic hypodermic needles may help reduce illness and disease due to unsterile re-use, as they may be more easily disabled and disposed of as compared to metal ones. This paper presents the fabrication of plastic hypodermic needles using micro-injection moulding and the analyses of their buckling behaviour. As a needle cannula is a thin-walled column (here 0.7 mm outer diameter with a 0.15 mm wall thickness), it is vulnerable to buckling. The buckling behaviour is characterized by numerical simulation and experiments, which are compared to the penetration forces for rubber skin mimic and human skin.

Disposable Equipment↗
PubMedDate not supplied

Admission motor impairment as a predictor of physical disability after stroke rehabilitation.

The purpose of this study is to investigate the Fugl-Meyer Motor Impairment Scale and physical disability as measured by the Functional Independence Measure (FIM) as predictors of physical independence after stroke inpatient rehabilitation. Forty-eight patients admitted to a rehabilitation hospital within 6 wk of their first unifocal stroke were prospectively studied. Upper and lower extremity Fugl-Meyer scores were obtained near rehabilitation admission. FIMs were obtained on admission and discharge. Discharge FIM self-care was predicted best by admission FIM total (rs = 0.75; P < 0.0001), although admission FIM self-care, other FIM components, and upper- and lower-extremity Fugl-Meyer scores were also good predictors. Discharge FIM mobility and locomotion correlated well with their admission counterparts (rs = 0.54 and 0.45; P < 0.001 and < 0.01, respectively) but were even more strongly related to admission Fugl-Meyer scores (rs = 0.63 and 0.74, respectively; P < 0.0001). As expected, cognitive and psychosocial components of the FIM at discharge correlated poorly with admission Fugl-Meyer. These data confirm the strong motor impairment basis for the physical disability subdimensions of the FIM and suggest that dependency in physical activities of daily living after stroke is primarily determined by degree of motor impairment.

Activities of Daily Living↗
PubMedDate not supplied

Bladder volume measurement with electrical impedance analysis in spinal cord-injured patients.

The purpose of the study contained herein was to determine the usefulness of electrical impedance for measurement of bladder volume in spinal cord-injured patients, with an assessment of the relationship between electrical impedance and bladder volume exclusively. The study was performed during urodynamic studies to match the exact bladder volume. Thirteen patients with complete spinal cord injuries were recruited. We used silver-silver chloride compound electrodes composed of one pair of current and amplitude electrodes to minimize the influence of superficial skin impedance. Each compound electrode was attached on the lower abdomen bilaterally after skin cleansing. Constant current (60 kHz-1.0 mA), converted from 9 V of direct current, was applied, and corresponding electrical impedance (omega) was measured at "pre" (before urodynamic empty bladder), "full" (with a urodynamic filled bladder), and "post" (after urodynamic empty bladder) status. Electrical impedance at the full status was definitely lower than that at the pre and post statuses in all subjects, with a statistically significant difference (P < 0. 001). The correlation between electrical impedance and bladder volume was negative (r = -0.7988), and the fact of how much the variation in electrical impedance could be explained by variation in bladder volume was estimated (r2 = 0.6381). From these findings, we have determined that the electrical impedance analysis technique can be an alternative measure of bladder volume indirectly.

Adult↗
PubMedDate not supplied

Replacement of a tracheal defect with autogenous mucosa lined tracheal prosthesis made from polypropylene mesh.

Reliable prosthetic or tissue grafts for the trachea have not, as yet, been developed for reconstruction of large, circumferential tracheal defects. Major limitations are anastomotic dehiscence and stenosis, attributed to the poor epithelialization and vascularization of the prosthetic graft. We have developed a new tracheal prosthesis that has a well vascularized and viable mucosa. The prosthesis consists of a Prolene mesh reinforced with polypropylene rings, and coated with gelatin. We lined the luminal surface of the prosthesis with transplanted autogenous oral mucosa, wrapped the prosthesis with greater omentum, and placed it in the peritoneal cavity for 2 weeks. Complete surgical resection and replacement of a segment (5 cm in length, 8 to 10 tracheal rings) of the thoracic trachea was then performed in nine adult mongrel dogs. The transplanted mucosa was well vascularized and maintained its normal histology in prereplacement analysis. Dogs with tracheal replacement regained their full activity and did not show any respiratory problems until sacrifice at 1, 2, and 6 months. After 6 months, the prostheses were completely incorporated by the host trachea in all dogs and confluent epithelialization was confirmed histologically from the upper to the lower anastomotic site of the prosthesis; furthermore, the transplanted mucosal cells had changed to ciliated columnar epithelium.

Animals↗
PubMedDate not supplied

T1 lung cancer on CT: frequency of extrathoracic metastases.

PURPOSE: To determine the frequency of extrathoracic metastases in T1 non-small-cell lung cancer. METHOD: Ninety patients with T1 lung cancer identified on CT were included. Extrathoracic metastases were evaluated at the time of initial diagnosis and during a 1-year follow-up study. The frequency of metastases was compared in terms of cell type (squamous or nonsquamous), size (<2 cm or >2 cm), and the initial CT findings of the tumor. RESULTS: Extrathoracic metastases were identified in 12 (13%) of 90 patients at the time of diagnosis and in 10 patients at the 1-year follow-up study (total, 22 of 90 [24%] patients). Tumors with ground-glass opacity on CT were associated with a significantly lower prevalence of metastases (p = 0.042). The area of ground-glass opacity was seen in 1 of 13 (85%) patients with bronchioloalveolar carcinoma and in 12 of 53 (23%) patients with adenocarcinoma other than bronchioloalveolar carcinoma (p < 0.001). There was no significant difference in the prevalence of metastases between squamous and nonsquamous cell carcinoma, between tumors smaller than 2 cm (n = 17) and larger than 2 cm in diameter (n = 73) and between tumors with or without mediastinal nodal metastases (p>0.05). CONCLUSION: Extrathoracic metastases were apparent at the initial examination in 13% of patients and at the 1-year follow-up examination in 11% of patients. The prevalence is significantly lower in tumors with ground-glass opacity.

Carcinoma, Non-Small-Cell Lung↗
PubMedDate not supplied

Severe spontaneous ovarian hyperstimulation syndrome with MR findings.

We describe a case of severe spontaneous ovarian hyperstimulation syndrome (OHSS) with MR findings. MR scans showed bilateral symmetric enlargement of ovaries with multiple cystic changes, giving the classic "wheel-spoke" appearance. There was no definite abnormally thickened or enhanced wall, but there was internal hemorrhage in some chambers. To avoid unnecessary laparotomy, we emphasize the importance of careful diagnosis to differentiate spontaneous OHSS from ovarian cystic neoplasms.

Adult↗
PubMedDate not supplied

A DBMS-based medical teleconferencing system.

This article presents the design of a medical teleconferencing system that is integrated with a multimedia patient database and incorporates easy-to-use tools and functions to effectively support collaborative work between physicians in remote locations. The design provides a virtual workspace that allows physicians to collectively view various kinds of patient data. By integrating the teleconferencing function into this workspace, physicians are able to conduct conferences using the same interface and have real-time access to the database during conference sessions. The authors have implemented a prototype based on this design. The prototype uses a high-speed network test bed and a manually created substitute for the integrated patient database.

Computer Graphics↗
PubMedDate not supplied

Randomized assessment of a warfarin nomogram for initial oral anticoagulation after venous thromboembolic disease.

Standard treatment for venous thromboembolism is parenteral heparin followed by warfarin. In this study we assess whether a standardized method of ordering warfarin reduces the duration of hospitalization. Consecutive patients were randomized to receive warfarin managed by attending physicians or by a nomogram. Patients were stratified according to primary or secondary venous thromboembolism. Prothrombin times were measured daily and heparin was given for a minimum of 5 days and stopped when the International Normalized Ratio was >1.9. Patients were followed for 3 months. There were 111 patients, 80 with primary and 31 with secondary venous thromboembolism. Overall there were no differences between the two warfarin groups with respect to length of admission. Given the prolonged duration of admission in many patients with secondary venous thromboembolism, a subset analysis was conducted on the 80 patients with primary venous thromboembolism. Patients in the standard group stayed significantly longer than patients in the nomogram group (6.0 vs. 5.6 days, p = 0.02). The warfarin nomogram as tested is safe and leads to a significantly shorter length of stay for patients with primary venous thromboembolism as compared to standard practice.

Administration, Oral↗
PubMedDate not supplied

The endoplasmic reticulum chaperone GRP94 is induced in the thyrocytes by cadmium.

We established a relationship between the toxic effects of cadmium on the expression of the endoplasmic reticulum (ER) chaperone GRP94 (glucose regulated protein 94) and cell survival in cultured rat-thyrocytes of FRTL5 cells. There are no data reporting that the enhanced expression of GRP94 by Cd stimulation is detectable in thyrocytes. Western blot analysis revealed higher levels of GRP94 expression in those cells post-treated with low concentrations of Cd, following a step-down treatment method, than in Cd pre-treated cells or cells not treated with any Cd, due to changes in cellular sensitivity after pre-treatment with Cd and the possible induction of GRP94 expression after removal of a low concentration of Cd. Elevated GRP94 expression in thyrocytes post-treated with Cd confers a survival advantage by rendering them resistant to cytotoxic stress, and the existence in the thyrocytes of a Cd-specific pathway regulates the expression of stress proteins by Cd.

Cadmium↗
PubMedDate not supplied

Involvement of endothelial nitric oxide synthase in the impaired endothelium-dependent relaxation of cavernous smooth muscle in hypercholesterolemic rabbit.

The present study was designed to evaluate whether functional impairment and/or protein expression of constitutive nitric oxide synthase (cNOS; endothelial NOS [eNOS] and neuronal NOS[nNOS]) was involved in impairment of endothelium-dependent relaxation of cavernous smooth muscle in hypercholesterolemic rabbits. New Zealand White rabbits were randomly divided into control and experimental groups. The control group (n=20) received a regular diet, while the two experimental groups (n=20 for each) were fed a 2% cholesterol diet for 4 and 8 weeks, respectively. We conducted isometric tension studies with endothelium-dependent and endothelium-independent vasodilators with or without preincubation with L-arginine and nonadrenergic, noncholinergic (NANC)-selective electrical field stimulation on isolated strips of corpus cavernosum. Expression of cNOS (eNOS and nNOS) protein was assessed by Western blot analysis. cNOS activities in both cytosolic and particulate fractions were measured by determining the conversion of L-[U-14C] arginine to L-[U-14C] citrulline. Blood levels of cholesterol were significantly higher (P < 0.01) in the experimental groups than in the control group. The relaxation responses to endothelium-dependent agents (acetylcholine and adenosine 5'-diphosphate [ADP]) were significantly reduced (P < 0.05) in both experimental groups, regardless of their incubation with L-arginine, compared with the control group. However, no differences were found among the three groups in the relaxation response to endothelium-independent agents (papaverine and nitroprusside) and to NANC-selective electrical field stimulation. There was no difference in immunoreactive nNOS from cytosolic and particulate fractions between the cavernous tissues of the control and experimental groups. nNOS protein levels in the particulate fractions were markedly lower than in the cytosolic fractions. The particulate cNOS activity was significantly decreased (P < 0.05) in the experimental groups compared with the control group, while the cytosolic cNOS activity in the experimental groups was not different from that found in the control group. Therefore, it is concluded that functional impairment of eNOS, rather than of nNOS, may lead to impairment of cavernous smooth muscle relaxation in response to endothelium-mediated stimuli in hypercholesterolemic rabbits.

Animals↗
PubMedDate not supplied

Enhanced hippocampal CA1 LTP but normal spatial learning in inositol 1,4,5-trisphosphate 3-kinase(A)-deficient mice.

To define the physiological role of IP(3)3-kinase(A) in vivo, we have generated a mouse strain with a null mutation of the IP(3)3-kinase(A) locus by gene targeting. Homozygous mutant mice were fully viable, fertile, apparently normal, and did not show any morphological anomaly in brain sections. In the mutant brain, the IP4 level was significantly decreased whereas the IP3 level did not change, demonstrating a major role of IP(3)3-kinase(A) in the generation of IP4. Nevertheless, no significant difference was detected in the hippocampal neuronal cells of the wild-type and the mutant mice in the kinetics of Ca2+ regulation after glutamate stimulation. Electrophysiological analyses carried out in hippocampal slices showed that the mutation significantly enhanced the LTP in the hippocampal CA1 region, but had no effect on the LTP in dentate gyrus (DG). No difference was noted, however, between the mutant and the wild-type mice in the Morris water maze task. Our results indicate that IP(3)3-kinase(A) may play an important role in the regulation of LTP in hippocampal CA1 region through the generation of IP4, but the enhanced LTP in the hippocampal CA1 does not affect spatial learning and memory.

Animals↗
PubMedDate not supplied

Genetic variation in susceptibility to Marek's disease in a commercial broiler population.

Two commercial broiler pure lines that were previously identified to differ in their susceptibility to Marek's disease (MD) were line-crossed to generate an F1 population. Eight F1 males were randomly mated to four or five F1 females to produce an F2 test population that would be segregating for genes affecting MD. All F2 progeny (four hatches) were pedigreed at hatch and placed in colony houses as nonvaccinated. At 5 days of age, they were challenged intraabdominally with MD virus RB1B. Clinical signs, mortality, and gross and microscopic lesions were recorded during the MD challenge. At 8 wk postchallenge, all remaining birds were euthanatized and necropsied. During the MD challenge of the first two hatches, we observed that several severely stunted broilers originated from certain families and the differences in body weight among birds appeared as early as 3 wk postchallenge. To confirm this observation, body weight at 6 wk postchallenge was determined for all surviving birds in hatches 3 and 4 (n = 242). Genetic variation in body weight among broiler sire families was apparent; the average body weight for males at this time was 2.07 kg, whereas with females, it was 1.87 kg. At least 12.2% of the broilers, including both sexes, weighed less than 1 kg ("severely stunted") at this time. The incidence of these growth-stunted birds within each broiler sire family ranged from 0 to 26% and for dam families, 0 to 60%. Correlation analyses between stunting and other MD-associated traits revealed that the incidence of stunting had a significant and positive association with paralysis (r = 0.50). Therefore, the data suggest that there may be a genetic component affecting body weight loss during MD infection. The genetic component is speculated to affect susceptibility to MD paralysis with an indirect effect on the body weight of birds. The significance of this finding is best exemplified by the identification of a broiler sire family with over 26% of its progeny affected by this MD-associated trait.

Animals↗