PubMed Health⌕ Search

Biomedical subjects

B G Kim

Publications and source records attributed to B G Kim.

At least 37 records · Page 2Linked to original sources
PubMed2000

Relative sparing of calretinin containing neurons in the substantia nigra of 6-OHDA treated rat parkinsonian model.

A certain calcium binding protein (CaBP) has been known to exert a neuroprotective effect in various neurodegenerative diseases. Using the 6-OHDA induced rat Parkinsonian model, we examined if calretinin (CR), one of CaBP family, could play the similar role in the Parkinson's disease because CR is profusely localized in dopaminergic neurons of the substantia nigra pars compacta (SNPC) of the rat. Employing immunohistochemical analyses, we found that the survival rate of CR neurons was significantly higher than that of tyrosine hydroxylase (TH) neurons in the SNPC of the Parkinsonian rat. Furthermore double-labeled fluorescent microscopy revealed that almost all surviving TH neurons were also positive to CR. Our data suggest that CR-positive neurons are less vulnerable to 6-OHDA and CR in the dopaminergic neurons may have a protective function for survival of these neurons in the experimentally induced Parkinsonian rat.

Animals↗
PubMed2000

Inhibition of interleukin-10 (IL-10) production from MOPC 315 tumor cells by IL-10 antisense oligodeoxynucleotides enhances cell-mediated immune responses.

Interleukin-10 (IL-10) has both inhibitory and stimulatory effects on diverse cell types of the immune system. It inhibits the antigen-presenting capacity of monocytes/macrophages and stimulates T cell proliferation. Although many tumors spontaneously release IL-10, the physiological relevance of this phenomenon to the in vivo antitumor immune response is not known. To elucidate the physiological role of tumor-released IL-10, we used IL-10-specific antisense oligodeoxynucleotides (AS-ODN) for the inhibition of IL-10 production from the tumor cells. Incubation of MOPC 315 plasmacytoma with IL-10 AS-ODN in vitro resulted in inhibition of IL-10 production and also in enhancement of the expression of major histocompatibility complex (MHC) class I, MHC class II, and B7-1 molecules. MOPC 315 cells incubated with IL-10 AS-ODN (MOPC-IL10AS) for 16 h in vitro showed reduced tumorigenicity in Balb/c mice. The mice implanted with MOPC-IL10AS effectively rejected the tumor graft, and showed strong cytotoxic T lymphocyte (CTL) activity against the parental MOPC 315 cells. In addition, MOPC-IL10AS were more effective as stimulator cells in mixed lymphocyte/ tumor cell culture, and as target cells in a CTL assay. These results imply that IL-10 spontaneously released from MOPC 315 cells inhibits their immunogenicity and that the inhibition of IL-10 production by IL-10 AS-ODN may be a way to enhance the host cellular antitumor immune response.

Animals↗
PubMed2000

Effect of Qi-training on blood pressure, heart rate and respiration rate.

To examine the physiological effects of Korean traditional Qi-training, we investigated the changes in blood pressure, heart and respiratory rates before, during and after ChunDoSunBup (CDSB) Qi-training. Twelve normal healthy CDSB Qi-trainees (19-37 years old; trained for 1.3 +/- 0.2 years; 9 men and 3 women) volunteered to participate in this study. Heart rate, respiratory rate, systolic blood pressure and rate-pressure product were significantly decreased during Qi-training. From these results, we suggest that CDSB Qi-training has physiological effects that indicate stabilization of cardiovascular system.

Adult↗
PubMed2000

Interpretation of Wada memory test for lateralization of seizure focus by use of (99m)technetium-HMPAO SPECT.

PURPOSE: Although the intracarotid amobarbital procedure (IAP) or Wada test is useful in lateralizing seizure focus in patients with temporal lobe epilepsy (TLE), the results of the IAP memory test are frequently nonlateralizing. An insufficient suppression of the medial temporal region contralateral to the seizure focus may contribute to the failure of lateralization. We tried to correlate IAP memory results with the functional changes in the contralateral medial temporal region as measured by single photon emission computed tomography (SPECT) during IAP. METHODS: We performed a (99m)technetium-(Tc) hexamethylene-propylene-amine-oxime (HMPAO) brain SPECT in 19 medial TLE patients during a contralateral IAP (sodium amobarbital injected contralateral to the seizure focus). Regional cerebral blood flow (rCBF) was measured in the contralateral medial temporal region. The amount of decrease in the rCBF was calculated by subtracting the previous measurement from the one obtained with the interictal SPECT. RESULTS: Ten (53%) patients passed and nine (47%) failed the contralateral IAP. The mean percentage decrease in rCBF was 5.3+/-5.3%. There was a significant negative correlation between a decrease in the rCBF and the IAP memory-retention score by Spearman correlation (p = -0.53: p<0.021). Patients with smaller decreases in rCBF (<5%) more frequently passed the contralateral IAP memory test than did those with larger decreases (80 vs. 22%; p<0.023). CONCLUSIONS: We suggest that an insufficient suppression of the contralateral medial temporal function is partly responsible for nonlateralizing IAP memory tests. An IAP-SPECT may be useful in interpreting IAP memory tests for the lateralization of seizure focus in TLE patients.

Adult↗
PubMed1999

Isolation and transformation of uracil auxotrophs of the edible basidiomycete Pleurotus ostreatus.

Uracil auxotrophs of Pleurotus ostreatus were isolated using the selectable marker, resistance to 5'-fluoro-orotic acid (5'-FOA). Two of the nine uracil auxotrophs obtained were transformed to prototrophy using plasmid pTRura 3-2 that contains the orotidine monophosphate decarboxylase (ura3) gene from Trichoderma reesei. Southern blot analyses of the transformants showed that the transforming DNA had integrated into the genome of the protoplasts. Using 2 x 10(7) protoplasts, this system gave a transformation efficiency of about 30 transformants per microg of DNA. Normal fruiting bodies were induced in the transformants by crossing them with wild-type monokaryons, and the basidiospores collected from these fruiting bodies showed a biased segregation rate to prototrophy. These results indicate the integrated DNA was stably inherited.

Aspartate Carbamoyltransferase↗
PubMed1999

Asymmetric synthesis of chiral amines with omega-transaminase.

The asymmetric synthesis of chiral amines using prochiral ketones was carried out with (S)-specific omega-transaminase (omega-TA) from Vibrio fluvialis JS17. This reaction is inhibited severely by both products, (S)-amine and deaminated ketone. In addition, thermodynamic equilibrium strongly favored the reverse reaction. L-Alanine proved to be the best amino donor based on easy removal of the products. Optimal pH of the reactions with both whole cells and cell-free extract was 7. Amino acceptor reactivities of ketone substrates and reaction profiles of the asymmetric synthesis showed that the initial rate as well as the reaction yield were lower when the resulting (S)-amine from a prochiral ketone substrate was a more reactive amino donor. The yield could be increased dramatically by removing pyruvate, which is a more inhibitory product than (S)-alpha-methylbenzylamine [(S)-alpha-MBA] when acetophenone and L-alanine are used as an amino acceptor and donor, respectively. The removal of pyruvate was carried out by incorporating lactate dehydrogenase (LDH) in cell-free extract or by using whole cells. The whole cell reaction yielded a much better result. When 25 mM benzylacetone and 30 mM acetophenone were used as an amino acceptor with 300 mM L-alanine, 90.2% and 92.1% of the reaction yields after 1 day were obtained with whole cells, respectively. Enantiomeric excesses of both (S)-alpha-MBA and (S)-1-methyl-3-phenylpropylamine [(S)-MPPA] were all above 99%.

Alanine↗
PubMed1999

Melatonin promotes osteoblast differentiation and bone formation.

Prior studies have demonstrated that the pineal hormone, melatonin, can stimulate chloramphenicol acetyltransferase activity in Drosophila SL-3 cells transfected with a chloramphenicol acetyltransferase reporter construct containing the response element of rat bone sialoprotein (BSP). Based on these findings, studies were performed to determine whether melatonin could similarly modulate the expression of BSP in two cell lines, the MC3T3-E1(MC3T3) pre-osteoblast and rat osteoblast-like osteosarcoma 17/2.8 cell. Initial studies demonstrated that MC3T3 cells grown in the presence of 50 nM melatonin underwent cell differentiation and mineralization by day 12 instead of the 21-day period normally required for cells grown in untreated media. Melatonin increased gene expression of BSP and the other bone marker proteins, including alkaline phosphatase (ALP); osteopontin; secreted protein, acidic and rich in cysteine; and osteocalcin in MC3T3 cells in a concentration-dependent manner. Levels of melatonin as low as 10 nM were capable of stimulating transcription of these genes when cells were grown in the presence of beta-glycerophosphate and ascorbic acid. Under these conditions, melatonin induced gene expression of the bone marker proteins; however, this does not occur until the 5th day after seeding the culture dishes. Thereafter, MC3T3 cells responded to melatonin within 2 h of treatment. The fully differentiated rat osteoblast-like osteosarcoma 17/2.8 cells responded rapidly to melatonin and displayed an increase in the expression of BSP, ALP, and osteocalcin genes within 1 h of exposure to the hormone. To determine whether melatonin-induced osteoblast differentiation and bone formation are mediated via the transmembrane receptor, MC3T3 cells were treated in the presence and absence of melatonin with either luzindole, a competitive inhibitor of the binding of melatonin to the transmembrane receptors, or pertussis toxin, an uncoupler of G(i) from adenylate cyclase. Both luzindole and pertussis toxin were shown to reduce melatonin-induced expression of BSP and ALP. These results demonstrate, for the first time, that the pineal hormone, melatonin, is capable of promoting osteoblast differentiation and mineralization of matrix in culture and suggest that this hormone may play an essential role in regulating bone growth.

3T3 Cells↗
PubMed1999

High-level secretory production of intact, biologically active staphylokinase from Bacillus subtilis.

Staphylokinase is a promising blood-clot dissolving agent for the treatment of patients suffering from a heart attack. It would be desirable to produce this protein in large quantities for biochemical characterization and clinical trials. Production of intact, biologically active staphylokinase from bacterial expression systems has been a challenge because of N-terminal microheterogeneity, plasmid instability, or low-production yield. By using a seven-extracellular-protease deficient Bacillus subtilis strain, WB700, intact staphylokinase can be produced via secretion. However, native staphylokinase gene (sak) in a high-copy number plasmid was found to be unstable in B. subtilis. To optimize the production and the stability of the expression vectors, both the promoter and the signal sequence of sak were replaced by B. subtilis promoters (P43, a constitutively expressed promoter; Pamy, a stationary-phase promoter; and PsacB, a sucrose-inducible promoter) and the levansucrase-signal sequence, respectively. This overcame the plasmid instability problem. To enhance transcription from the sacB promoter, degQ encoding a transcriptional activator for sacB and other protease genes was also installed in the expression vector. The use of WB700 as the expression host allowed enhanced production of staphylokinase from the sucrose-inducible plasmid without causing any obvious degradation of staphylokinase. Both the P43 and PsacB (with DegQ) promoters worked well. Over 90% of staphylokinase synthesized can be secreted effectively. With the optimization of both the culture media and the fermentation conditions, production of staphylokinase reached a level of 337 mg/L, and staphylokinase could be purified to homogeneity by a simple three-step purification scheme. Secreted staphylokinase did not show any N-terminal heterogeneity. This presents an attractive system for the production of staphylokinase in both high quality and quantity.

Amino Acid Sequence↗
PubMed1999

Evaluation of functional changes in the medial temporal region during intracarotid amobarbital procedure by use of SPECT.

PURPOSE: Because the main blood supply to the medial temporal region is through the posterior cerebral artery, the validity of the intracarotid amobarbital procedure (IAP) is still debated. To verify clinical validity of the IAP, we investigated changes in neuronal function in the medial temporal region during IAP. METHODS: Brain single photon emission computed tomography (SPECT) was performed during IAP (IAP-SPECT) in 22 patients with temporal lobe epilepsy (TLE), and regional cerebral blood flow (rCBF) in the medial and lateral temporal regions of interest (ROIs) was measured quantitatively. To determine the distribution of sodium amobarbital, in another 20 patients with TLE, SPECT images were obtained after intracarotid injection of 99mTc-HMPAO mixed with sodium amobarbital. RESULTS: Mean rCBF was 89.2% in the medial temporal region and 81.6% in the lateral temporal region: in the former region, it was significantly lower than that shown by the results of interictal SPECT (99.1%; p < 0.001). In a few patients, however, rCBF did not decrease in the medial temporal region. In only 25% of patients, the medial temporal region was visualized in SPECT images obtained after intracarotid injection of 99mTc-HMPAO. CONCLUSIONS: The results in this study demonstrate that IAP is valid because the medial temporal region is inactivated in spite of infrequent delivery of sodium amobarbital. We assume that intratemporal diaschisis is operating for the inactivation of neuronal function. IAP-SPECT with intratemporal ROIs may be useful for monitoring changes in neuronal function in the medial temporal region during IAP.

Adolescent↗
PubMed1999

A Minnesota multiphasic personality inventory profile of ChunDoSunBup qi-trainees: a preliminary study.

The aim of this study is to explore the effects of ChunDoSunBup Qi-training on personality traits. Twenty-six normal healthy subjects (mean age = 26.58 +/- 6.56) and 26 CDSB Qi-trainees (mean age = 27.74 +/- 5.21) participated in this study. Analysis of MMPI profiles showed that CDSB Qi-trainees scored significantly lower on Depression (D), Hysteria (Hy), Paranoia (Pa), Schizophrenia (Sc) and Frequency (F) and significantly higher on the Correction (K) Scales. In addition, CDSB Qi-trainees reported a significantly lower Cook-Medley Hostility (Ho) scale than that of controls. This preliminary study suggests that CDSB Qi-training may be effective in protection as well as restoration of emotional, psychological symptomatology and personality trait disorder.

Adult↗
PubMed1998

Kinetic modeling of omega-transamination for enzymatic kinetic resolution of alpha-methylbenzylamine.

A kinetic model for omega-transaminase from Bacillus thuringiensis JS64 was developed by using the King-Altman method to simulate the kinetic resolution of alpha-methylbenzylamine (alpha-MBA). Starting from a ping-pong bi-bi mechanism, a complete kinetic model including substrate inhibition only in the reverse reaction (i.e., transamination between acetophenone and L-alanine) was developed. The asymmetric synthesis of (S)-alpha-MBA proved to be difficult due to a much lower maximum reverse reaction rate than the maximum forward reaction rate, thermodynamically exergonic forward reaction (i.e., transamination between (S)-alpha-MBA and pyruvate), and the severe product and substrate inhibition of the reverse reaction. Experimental values for kinetic parameters show that the product inhibition constant of (S)-alpha-MBA is the most important parameter on determining the resolution reaction rate, suggesting that the resolution reaction rate will be very low unless (S)-alpha-MBA strongly inhibits the reverse reaction. Using the kinetic model, the kinetic resolution of alpha-MBA in aqueous buffer was simulated, and the simulation results showed a high degree of consistency with experimental data over a range of reaction conditions. Various simulation results suggest that the crucial bottleneck in the kinetic resolution of alpha-MBA lies mainly in the accumulation of acetophenone in reaction media as the reaction proceeds, whereas L-alanine exerts a little inhibitory effect on the reaction. The model predicts that removing acetophenone produced during the reaction can enhance the reaction rate dramatically. Indeed, the biphasic reaction system is capable of extracting acetophenone from the aqueous phase, showing a much higher reaction rate compared to a monophasic reaction system. The kinetic model was also useful in predicting the properties of other, better enzymes as well as the optimal concentrations of amino acceptor and enzyme in the resolution reaction.

Acetophenones↗
PubMed1996

Spectrophotometric assay using streptavidin-alkaline phosphatase conjugate for studies on the proteolysis of polymer bead-bound peptides.

A simple method for indirectly measuring the concentration of biologically available peptides on the surface of polymer beads synthesized for the peptide or nonpeptide library is developed. To identify very small differences in the amount of cleaved peptides after alpha-chymotrypsin treatment, the so-called "shaving" process, a system of biotin and streptavidin-alkaline phosphatase conjugate was used. To this conjugate, 5-bromo-4-chloro-3-indolyl phosphate and nitro blue tetrazolium (NBT) are coupled consecutively, to carry out alkaline phosphatase reaction and color reaction, respectively. The proteolytic action of alpha-chymotrypsin on surface peptides located on polymer beads was detected and cleaved peptides were quantified spectrophotometrically by analyzing unreacted NBT. Using this method, the enzymatic "shaving" process of surface peptides on polymer beads can be optimized by examining the effects of the morphology of polymer beads and the length of spacers on how easily enzymes such as alpha-chymotrypsin can access the surface of polymer beads. Quantitative understanding of molecular interactions on the bead surface will give us very useful information in designing polymer bead and bead-bound oligopeptide structures for the peptide or nonpeptide library.

Alkaline Phosphatase↗
PubMed1996

Relationship between squamous cell carcinoma antigen levels and tumor volumes in patients with cervical carcinomas undergoing neoadjuvant chemotherapy.

This study was performed to determine whether there is a linear correlation between serum squamous cell carcinoma (SCC) antigen levels and tumor volumes in patients with cervical carcinoma. Sera from 43 patients with stage IIb bulky (>4 cm) cervical carcinoma were collected prospectively and assayed for SCC antigen levels before, and 2 weeks after, three courses of neoadjuvant chemotherapy. At the same time, tumor volume was measured by pelvic magnetic resonance imaging (MRI). Mean serum SCC antigen level declined significantly after neoadjuvant chemotherapy, from 16.8 ng/ml (range 0.4-80.2 ng/ml) to 3.1 ng/ml (range 0.1-13.0 ng/ml) (P = 0.0001). Also, the percentage of patients with elevated serum SCC antigen level decreased significantly from 79.1 to 25.6% (P < 0.001). Furthermore, mean tumor volume also declined significantly after neoadjuvant chemotherapy, from 54.1 cm3 (range 8.4-133.9 cm3) to 5.3 cm3 (range 0-77.8 cm3) (P = 0.0001). However, serum SCC antigen levels did not show a linear correlation with tumor volumes before and after neoadjuvant chemotherapy (r = 0.0776, P = 0.6208; r = 0.1887, P = 0.2256, respectively). Interestingly, the percentage reduction in serum SCC antigen levels showed a linear correlation with that of tumor volume after neoadjuvant chemotherapy in 34 patients who had elevated prechemotherapy serum SCC antigen levels (r = 0.5094, P = 0.0021). These results suggest that although serum SCC antigen level does not have a direct linear relationship to tumor volume, reduction in serum SCC antigen level has a linear correlation with that of tumor volume after neoadjuvant chemotherapy in patients with cervical carcinoma and elevated prechemotherapy SCC antigen levels.

Antigens, Neoplasm↗
PubMed1996

Optimization of environmental factors for the production and handling of recombinant retrovirus.

Certain steps from the production to infection of the amphotropic retroviral vector, MFG- LacZ, were optimized and the factors that affect retroviral titers were analyzed. Retroviral vector titers were highest when the culture supernatant was harvested 3 days after the producer cells had reached confluence. About a 2-fold increase in vector production was achieved at 32 degrees C compared to that at 37 degrees C. Low serum concentrations had no significant effect on the titers of virus produced by the CRIP cell line. Retroviral vectors were stable at 4 degrees C but very unstable at 37 degrees C and were quite sensitive to freezing and thawing. About 30%-50% of viral infectivity was lost during the thawing step and the loss was not recovered by the addition of commonly used cryoprotectants. Increase in viral exposure time for infection to target NIH3T3 cells was linearly proportional to the retroviral titer for up to 15 h. In addition, using DEAE-dextran in place of polybrene as a polycation during infection enhanced infection efficiency about 3-fold. The retrovirus was robust to simple ultrafiltration and its titer could be easily concentrated 16-fold. Taken together, our data suggest that at least a 100-fold increase in titer can be achieved with simple optimization.

3T3 Cells↗
PubMed1996

Clinical utility of calculated creatinine clearance as a guide to chemotherapy in patients with gynecologic malignancies.

OBJECTIVE: To examine the relationship between calculated and measured creatinine clearance, and also to evaluate the clinical utility of calculated creatinine clearance before administration of chemotherapy in patients with gynecologic malignancies. METHODS: In 38 patients with gynecologic malignancies, a total-69 paired creatinine clearance measured by 24-hour urinary creatinine clearance and calculated were compared. RESULTS: The significant correlation (r = 0.597, p < 0.0001) was observed between creatinine clearances determined by both methods. There were 26 (37.7%) 24-hour urine collections. The correlation between two methods improved when these inaccurate samples were excluded (r = 0.876, p < 0.0001). In addition, if a creatinine clearance of 50 ml/min is set as a threshold for dose modification, only 2.9% of the patients would have received reduced doses inappropriately, by using the calculated creatinine clearance alone. CONCLUSION: These results suggest that in patients with gynecologic malignancies, a calculated creatinine clearance prior to chemotherapy is sufficient for evaluation of renal function and measured creatinine clearance would be determined only when calculated creatinine clearance is below the threshold for dose modification.

Adult↗
PubMed1996

Expression of urokinase-type plasminogen activator, its receptor, and its inhibitor in gastric adenocarcinoma tissues.

The plasminogen and plasmin system, which is mainly regulated by urokinase-type plasminogen activator (uPA), its receptor (uPAR) and its inhibitor (PAI-1), is generally believed to play a role in cancer invasion and metastasis. This study was conducted to investigate the role of uPA, uPAR and PAI-1 in the invasion and metastasis of gastric adenocarcinoma. The expression of mRNAs for uPA and PAI-1 was determined by Northern blot analysis in nine primary gastric cancer tissues, nine paired metastatic lymph nodes and normal gastric mucosa. The mRNA of uPA was not or faintly detected in normal mucosa, while the expression was increased in both primary gastric cancer tissues and metastatic lymph nodes to a similar degree. The mRNA expression for PAI-1 in the gastric cancer tissues was not different from that in the paired metastatic lymph nodes and normal mucosae. uPAR was determined by immunohistochemical staining, demonstrating that five (56%) and six (67%) out of nine primary gastric cancer tissues and nine paired metastatic lymph nodes were positive, respectively and the intensity was stronger in metastatic lymph nodes. The results support the concept that most gastric cancer cells may have an innately moderate level of uPA and uPAR, and that increase of uPAR expression can be considered to be closely associated with cancer invasion and metastasis.

Adenocarcinoma↗
PubMed1995

Phase I/II study of neoadjuvant intraarterial chemotherapy with mitomycin-C, vincristine, and cisplatin in patients with stage IIb bulky cervical carcinoma.

BACKGROUND: Stage IIb bulky cervical carcinomas have been considered difficult to treat successfully by radiation and/or surgery, compared with smaller lesions. This study was designed to evaluate the efficacy of neoadjuvant pelvic intraarterial chemotherapy (IAC) and to determine the optimal dosage of cisplatin for reducing tumor volume in these patients. METHODS: Twenty-one previously untreated patients with primary cervical carcinoma of more than 4 cm in greatest dimension and parametrial invasion were included in this study. Pelvic IAC was administered using a combination of mitomycin-C, 10 mg/m2; vincristine, 1 mg/m2; and cisplatin, 50 mg/m2 (MVC; group 1, 8 patients) or 75 mg/m2 (group 2, 13 patients). Tumor volumes were measured three-dimensionally by magnetic resonance imaging (MRI) before and after three courses of IAC. Clinical responses were evaluated with gynecologic examination and MRI; pathologic responses were evaluated with histologic examinations of surgical specimens. RESULTS: The mean volume reduction rate (74.2% vs. 97.2% in groups 1 and 2, respectively, P = 0.0022), the clinical complete response rate (0% vs. 69.2%, P = 0.0033), and the pathologic complete response rate (0% vs. 46.2%, P = 0.0445) were significantly higher in group 2. Type III radical hysterectomy was possible in 19 patients (90.5%). Toxicities of grades 2-3 (World Health Organization criteria) were nausea and/or vomiting (38.1%), leukopenia (33.3%), and fever (14.2%). CONCLUSIONS: These preliminary results suggest that neoadjuvant pelvic IAC with MVC (especially with cisplatin at a dose of 75 mg/m2) is effective in reducing tumor volume, increasing the clinical and pathologic complete response rate, and improving the operability in most patients with Stage IIb bulky cervical carcinoma, generally considered inoperable.

Adult↗