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Biomedical subjects

Y G Kim

Publications and source records attributed to Y G Kim.

At least 19 recordsLinked to original sources
PubMed1997

Effect of mandibular setback surgery on occlusal force.

PURPOSE: This study investigated the effect of mandibular setback surgery on occlusal force and evaluated the extent to which postsurgical changes in such force can be explained by the type of operation, the duration of maxillo-mandibular fixation (MMF), and the changes in the mechanical advantage of the jaw musculature. MATERIALS AND METHODS: Maximal molar bite force was measured before surgery and at MMF removal, and 3, 6, and 12 months thereafter in 26 patients with mandibular prognothism. To correlate bite force and skeletal change, the cephalometric tracings were measured, tabulated, and statistically analyzed. RESULTS: Mean bite force was 13.7 kg before surgery, 7.6 kg at MMF removal, 14.2 kg at 3 months, 19.7 kg at 6 months, and 26.1 kg at 12 months post-surgery. The bite force was positively correlated with the surgical change in mandibular plane angle and mandibular body length. The recovery of bite force was significantly affected by the type of operation and duration of MMF. CONCLUSIONS: To hasten recovery and increase bite force after orthognathic surgery, long periods of MMF and injury to the masticatory muscles should be avoided.

Adolescent↗
PubMed1997

Superoxide dismutase activity and lipid peroxidation in the liver of guinea pig infected with Leptospira interrogans.

Superoxide dismutase (SOD) activity and the degree of lipid peroxidation were studied over a two week period in guinea pigs infected with Leptospira interrogans derived from wild mice. The total SOD activity in infected host liver increased by four-fold two days after infection; this was followed by a 20% decrease resulting in levels comparable to normal, uninfected liver. During the period of decreasing SOD activity after day two, the levels of TBA-reactive material (TBARS) are increased by three-fold in infected guinea pig, liver, compared to uninfected liver. The results indicate that SOD attenuates intracellular superoxide-mediated toxic effects in guinea pigs infected with L. interrogans. In addition, electron microscopy structure demonstrates correlated pathogenic shrinkage of mitochondrial and Kupffer cell structures.

Animals↗
PubMed1996

Hybrid restriction enzymes: zinc finger fusions to Fok I cleavage domain.

A long-term goal in the field of restriction-modification enzymes has been to generate restriction endonucleases with novel sequence specificities by mutating or engineering existing enzymes. This will avoid the increasingly arduous task of extensive screening of bacteria and other microorganisms for new enzymes. Here, we report the deliberate creation of novel site-specific endonucleases by linking two different zinc finger proteins to the cleavage domain of Fok I endonuclease. Both fusion proteins are active and under optimal conditions cleave DNA in a sequence-specific manner. Thus, the modular structure of Fok I endonuclease and the zinc finger motifs makes it possible to create "artificial" nucleases that will cut DNA near a predetermined site. This opens the way to generate many new enzymes with tailor-made sequence specificities desirable for various applications.

Bacteriophage lambda↗
PubMed1996

Pharmacokinetics of DA-125, a new anthracycline, after intravenous administration to uranyl nitrate-induced acute renal failure rats or protein-calorie malnutrition rats.

The pharmacokinetics of DA-125 were compared after intravenous (i.v.) administration of the drug, 10 mg kg-1, to control male Sprague-Dawley rats (n = 9) and uranyl nitrate-induced acute renal failure (U-ARF, n = 12) rats, or male Sprague-Dawley rats fed on a 23% (control, n = 8) or a 5% (protein-calorie malnutrition, PCM, n = 9) protein diet. After i.v. administration of DA-125, almost 'constant' plasma concentrations of M1, M2, and M4 were maintained from 1-2 h to 8-10 h in all rat groups due to the continuous formation of M2 from M1 and M4 from M3. The plasma concentrations of M3 were the lowest among M1-M4 for all rat groups due to the rapid and almost complete conversion of M3 to M4 and other metabolite(s). The AUCt values of M1 (115 against 82.5 micrograms min mL-1), M2 (33.0 against 23.6 micrograms min mL-1), and M4 (26.3 against 15.1 micrograms min mL-1) were significantly higher in the U-ARF rats than in the control rats. The percentages of i.v. dose excreted in 24 h urine as M1 (under the detection limit against 0.316%), M2 (under the detection limit against 5.58%), and M4 (0.0174 against 0.719%)--expressed in terms of DA-125--were significantly lower in the U-ARF rats than in the control rats, and this could be due to the decreased kidney function in the U-ARF rats. However, the percentages of i.v. dose recovered from the GI tract at 24 h as M1 (0.0532% against under the detection limit), M3 (0.0286% against under the detection limit), and M4 (0.702% against 0.305%)--expressed in terms of DA-125--were significantly greater in the U-ARF rats than in the control rats. All U-ARF rats had ascites, but the concentrations of M1 (0.0320 micrograms mL-1), M2 (0.0265 micrograms mL-1), M3 (under the detection limit), and M4 (0.032 micrograms mL-1) in the ascites from one rat were almost negligible. The plasma concentrations and most of the pharmacokinetic parameters of M1, M2, and M4 were not significantly different between the PCM rats and their control rats.

Acute Kidney Injury↗
PubMed1996

Chromosomal numerical aberrations in gastric carcinoma: analysis of eighteen cases using in situ hybridization.

Paraffin-embedded tumor cells of 18 cases of gastric carcinoma were hybridized with digoxigenin-labeled repetitive DNA probes specific for the centromeric regions of chromosomes X, Y, 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 15, 16, 17, 18, and 20. All cases demonstrated numerical chromosomal aberrations. The most exciting aberration, polysomy (five or more copies) of several chromosomes, was found in all cases except a case of mucinous adenocarcinoma, which showed trisomy 9 as the sole chromosomal numerical aberration. In nine cases of tubular adenocarcinoma, poorly-differentiated polysomies of several chromosomes were the consistent numerical aberration and monosomy 7, 18(2 cases each), 10, and 17(1 case each) were also found. In moderately-differentiated tubular adenocarcinoma all three cases also showed polysomies of several chromosomes. The total number of extra chromosomes (polysomy was counted as 5 copies) was higher in the intestinal type (mean 20.9) than in the diffuse type (mean 14.1). Regional lymph node metastasis, vein invasion, or perineural invasion was not related to any specific chromosomal numerical aberration in gastric cancer. Chromosomes X, 1, 2, 3, 4, 15, 17, and 20 had extra copies especially polysomy in most cases. However, chromosomes 7 and 18 revealed monosomy in many cases (31.3% and 33.3% respectively, and chromosome 9 and 11 revealed trisomy in 35.7% and 75% each. Numerically, the most conserved chromosome in gastric cancer was chromosome 12 (62.5%). By flow cytometry, two diploidy and 8 aneuploidy cases with the DNA indices from 1.30 to 1.85 were found.

Adult↗
PubMed1996

Counts of common and atypical melanocytic nevi in Korean young men: assessment of their risks and correlations with associated factors.

Two hundred and thirty-five Korean young men were examined for the count of melanocytic nevi (MN). The mean count of common MN of at least 2 mm diameter was 16.1. Three subjects had more than 50 common MN and another four had clinically atypical MN. We determined skin phototype by interview with questionnaires in the same persons as proposed by Fitzpatrick. All subjects were classified with respect to skin phototype and the number of previous sunburns. The correlations between common MN and the skin phototype or the number of previous sunburns were statistically analyzed. The skin phototype showed the correlation with the number of common MN, which means if skin phototype of any subject belongs to type I, he could to be predicted to have many more common MN than subjects with darker phototypes, like type VI. The correlation between number of previous sunburns and number of common MN was not statistically significant. This study shows persons at moderate risk of cutaneous melanoma (CM) do exist and skin phototype is associated with the prevalence of common MN in Koreans.

Adolescent↗
PubMed1996

Tuberculosis-associated hemophagocytic syndrome in a hemodialysis patient: case report and review of the literature.

We present an unusual hematologic manifestation of tuberculosis in a hemodialysis patient. A 37-year-old man was admitted because of fever, anorexia, and weight loss which developed 3 months earlier. He previously received a renal transplant and commenced hemodialysis 1 year ago. Physical examination revealed hepatomegaly, and peripheral blood counts revealed pancytopenia. The delayed bone marrow biopsy demonstrated marked hemophagocytosis, granuloma and tubercle bacilli by the acid-fast stain. The clinical course was fatal and he died without definite treatment. Through this case, we would like to recommend early bone marrow biopsy and antituberculosis therapy if fever of unknown origin, anorexia, weight loss, hepatomegaly and pancytopenia develop in patients undergoing dialysis.

Adult↗
PubMed1996

Protein and messenger RNA expression of connexin43 in astrocytomas: implications in brain tumor gene therapy.

The expression of connexin43, the primary gap-junction constituent of glial cells, was evaluated at the messenger RNA and protein levels in different grades of astrocytoma to investigate the relevance of gap junctions in herpes simplex virus-thymidine kinase (HSV-tk)-mediated gene therapy of brain tumors. Transduction of the retroviral-mediated HSV-tk gene into tumor cells with subsequent administration of ganciclovir has recently been used as an experimental therapeutic strategy for treatment of brain tumors. One aspect of this approach is the bystander effect, which augments the efficacy of this therapeutic approach. Glioblastoma cells with minimum levels of connexin43 protein were transfected with a connexin43 complementary DNA. These cells manifested a marked increase in the in vitro bystander effect, supporting the contention that the in vitro bystander effect is a consequence of metabolic cooperation between cells mediated by gap junctions. To assess relative levels of gap-junction protein expression in the relevant tumor type, we examined primary astrocytomas, primary astrocytoma cell cultures, and glioblastoma cell lines. Although most astrocytoma tumor samples expressed connexin43, they differed in the level of expression, with the greatest variation exhibited in high-grade astrocytomas. Primary glioblastoma cell cultures and established glioblastoma cell lines also displayed some variability in connexin43 levels. In aggregate, our results anticipate that glioblastomas will have a varied bystander effect during HSV-tk gene therapy depending on the level of connexin43 expression.

Astrocytoma↗
PubMed1996

Medial collateral ligament injuries of the knee: ultrasonographic findings.

The aims of our study were (1) to describe the ultrasonographic findings of the injured medial collateral ligament of the knee and (2) to assess the usefulness of ultrasonography in both evaluating the presence and location of the medial collateral ligament injuries and predicting the prognoses for the patients. The study group consisted of 16 patients with the clinical diagnosis of medial collateral ligament injury. We also examined 20 knee joints in 10 volunteers who had no history of injury to the knee. To predict prognoses, we divided the patients into two groups on the basis of the location of medial collateral ligament injuries. A thickened and heterogeneously hypoechoic appearance of the medial collateral ligament was considered abnormal. The normal medial collateral ligament was a thin and moderately homogeneous hypoechoic band with an average thickness of 4.3 mm (range, 3.3 to 5.6 mm) at the femoral attachment and of 2.3 mm (range, 1.3 to 3.2 mm) at the tibial attachment. All injured medial collateral ligament structures were thickened and heterogeneously hypoechoic. According to the criteria for grading of medial collateral ligament injury with stress view, 10 patients had grade III medial collateral ligament tears, three had grade II tears, and none had grade I injuries. In 15 (94%) of 19 knees, a correct diagnosis could be made with ultrasonography. Ultrasonography is useful in evaluating isolated medial collateral ligament injuries and in predicting patient outcome on the basis of the location of the medial collateral ligament injuries.

Adult↗
PubMed1995

Status signaling games in animal contests.

This paper provides evolutionary game-theoretic models for the status signaling problem in animal contests. Two stage status signaling game models are introduced and evolutionarily stable strategies and their modifications are characterized for the games. It is shown that in the stable long-run equilibria, animals must make use of signals systematically to settle the contest peacefully.

Animals↗
PubMed1995

Physicochemical effects of a new slow-release potassium phosphate preparation (UroPhos-K) in absorptive hypercalciuria.

A new slow-release, neutral potassium phosphate salt (UroPhos-K) has been formulated in order to minimize gastrointestinal side effects and avoid sodium-induced calciuria. It was tested in a prospective randomized, double-blind trial in a group of 21 kidney stone patients with absorptive hypercalciuria type I (AH). Twelve patients allocated to the UroPhos-K group received four tablets twice daily with breakfast and an evening snack providing 1240 mg of phosphorus and 63.5 mEq of potassium daily. Nine patients assigned to the placebo group received placebo tablets of the same appearance containing excipient only. Subjects were studied during a 3-day period in the hospital while consuming a constant metabolic diet containing 400 mg Ca, 100 mEq Na, and 800 mg P per day before and after 3 months of treatment. Treatment with UroPhos-K did not cause any significant gastrointestinal side effects; nor did it raise fasting serum K or phosphorus, or reduce hemoglobin or creatinine clearance. It was associated with a rise in urinary K from 46 +/- 7 to 98 +/- 9 mEq per day and phosphorus from 744 +/- 185 to 1535 +/- 112 mg per day (p < 0.001 each). UroPhos-K treatment reduced urinary Ca from 288 +/- 63 to 171 +/- 49 mg/day (p < 0.001), without altering oxalate excretion. It reduced the urinary saturation of calcium oxalate without altering that of brushite. Moreover, by increasing urinary excretion of inhibitors (citrate and pyrophosphate), it reduced the propensity for spontaneous nucleation of brushite (increased formation product of brushite) and inhibited crystal agglomeration of calcium oxalate.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

Self-expandable metallic stents in high-risk patients with benign prostatic hyperplasia: long-term follow-up.

PURPOSE: To evaluate the long-term clinical utility of self-expandable metallic Z stents in benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: Under fluoroscopic guidance, 14 multiple-connected Z stents (10 mm in diameter fully expanded, 30-60 mm in length) were placed in 13 patients with bladder obstruction from BPH and high operative risks. The stents were placed in the prostatic urethra with 2-20-mm protrusion into the urinary bladder in six patients (group A) and entirely within the prostatic urethra in seven patients (group B). RESULTS: Eleven of 13 patients could void immediately, and the other two patients with atonic bladder voided within 8 weeks. Maximum urine flow rates just after stent placement were 8-27 mL/sec. Two patients died of unrelated causes within 2 months. During the follow-up period (mean, 37 months) in the other 11 patients, all patients in group A but none in group B underwent surgery owing to stone formation where the stent protruded into the bladder. CONCLUSION: Expandable Z stents are effective in patients with BPH but should not protrude into the urinary bladder because of stone formation.

Aged↗
PubMed1995

Design of an emergency teleradiology system based on progressive transmission.

In clinical surgery, there are frequent needs for communication between the house staff and the attending physician in an emergency situation. To overcome the limitation of voice communication through the telephone line, we have designed an 'emergency teleradiology system' which can be used for emergency surgical and medical decision making. This system can transmit the high quality images of CT, MRI, and other X-ray data using a PC attached to a modem through the conventional telephone line. It is based on the progressive transmission system which enables the successive update of a received image. The iterative residual coding/decoding algorithm efficiently compresses the image to maximally utilize the low bandwidth PSTN channels. This system also satisfies design requirements such as low-cost, ease of operation, fast transmission, and interactive image communication including voice. Test results using several CT, MR, and X-ray images evaluate the compression performance, image quality, transmission time and computational time of the coding and decoding processes, thus demonstrate the usefulness of this system in an emergency situation.

Algorithms↗
PubMed1994

Insertion and deletion mutants of FokI restriction endonuclease.

FokI restriction endonuclease recognizes the nonpalindromic pentadeoxyribonucleotide, 5'-GGATG-3':5'-CATCC-3' in duplex DNA and cleaves 9 and 13 nucleotides away from the recognition site. We have reported the presence of two distinct and separable protein domains within this enzyme: one for the sequence-specific recognition of DNA (the DNA binding domain) and the other for the endonucleases activity (the cleavage domain). Our studies have suggested that the two domains are connected by a linker region, which appears to be amenable for repositioning of the DNA-sequence recognition domain with respect to the catalytic domain. Here, we report the construction of several insertion (4-, 8-, 12-, 18-, 19-, or 23-amino acid residues) and deletion (4- or 7-amino acid residues) mutants of the linker region of FokI endonuclease. The mutant enzymes were purified, and their cleavage properties were characterized. The mutants have the same DNA sequence specificity as the wild-type enzyme. However, compared with the wild-type enzyme, the insertion mutants cleave predominantly one nucleotide further away from the recognition site on both strands of the DNA substrate. The four-codon deletion mutant shows relaxed specificity at the cut site while the seven-codon deletion appears to inactivate the enzyme. The DNA binding and cleavage domains of FokI appear to be linked by a relatively malleable linker. No simple linear relationship exists between the linker length and the distance of the cut site from the recognition site. Furthermore, the four-codon insertion mutants cleave DNA substrates containing hemi-methylated FokI sites; they do not cleave fully methylated substrates. These results are best explained as a consequence of protein-protein interactions between the domains.

Amino Acid Sequence↗