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Biomedical subjects

S W Kim

Publications and source records attributed to S W Kim.

At least 127 records · Page 7Linked to original sources
PubMed2001

Seroepidemiological study of Helicobacter pylori infection in asymptomatic people in South Korea.

BACKGROUND: Helicobacter pylori infection occurs throughout the world and causes gastroduodenal diseases in all age groups. The prevalence of H. pylori infection varies between countries and races. The aim of this study was to evaluate the seroprevalence of H. pylori infection in asymptomatic healthy people in South Korea. METHODS: From March 1998 to October 1998, 5732 asymptomatic subjects who responded to the self-assessment questionnaires from 54 hospitals in South Korea were enrolled in this study. The serum levels of antibodies for H. pylori immunoglobulinG were measured by using an ELISA test. RESULTS: The overall seroprevalence of H. pylori infection was 46.6% and there was no statistical difference between males (47.2%) and females (45.9%). In adults, a significant difference was observed between genders. According to the geographic areas, the high prevalent provinces were Kangwon (53.4%), Cheju (52.9%) and Cholla province (50.6%); Seoul (41.9%) was the lowest prevalent area. The seroprevalence increased with age and was highest when patients were aged in their 40s (78.5%). The characteristic feature of our study was that the infection rate was steeply increased in three age groups (10-12 year olds, 16-19 year olds and those aged in their 20s). In Seoul, there was no difference in the prevalence rate among the districts studied. CONCLUSIONS: This nation-wide seroprevalence of H. pylori infection in South Korea was 46.6%, which showed the transition from a developing country to a developed country. More studies on the epidemiological factors and the route of transmission of H. pylori infection should be warranted.

Adolescent↗
PubMed2001

Prophylactic efficacy of a new gentamicin-releasing urethral catheter in short-term catheterized rabbits.

OBJECTIVE: To describe an indwelling urethral catheter coated with gentamicin sulphate on the inner and outer surface of the catheter, and to evaluate the efficacy and safety of this catheter in preventing catheter-associated infections in rabbits. Materials and methods Sixty rabbits were divided equally into control and experimental groups which were then subdivided equally according to the duration of catheterization (1, 3 and 5 days). Silicone-treated latex catheters were used in the control group and gentamicin-releasing catheters in the experimental group. Urine samples and surface swabs from the catheter were cultured for bacteriological assessment, and the catheter surface examined by scanning electron microscopy to structurally analyse the biofilms. RESULTS: The gentamicin-releasing catheter reduced the incidence of bacteriuria (defined as > or = 100 c.f.u./mL) after both 3 and 5 days of catheterization (eight and 10 rabbits, respectively, for the control catheter, vs two and four rabbits for the gentamicin-releasing catheter, P < 0.05). The surfaces of the gentamicin-releasing catheter were colonized less often than those of the control catheter after both 3 and 5 days (eight and 10, respectively, for the control, vs one and four for the gentamicin-releasing catheter, P < 0.05). Scanning electron microscopy showed the formation of bacterial biofilm throughout the 3-day and 5-day control catheters, but deterioration of the bacterial biofilm was visible on the surface of the gentamicin-releasing catheters. CONCLUSION: This new gentamicin-releasing catheter produced an antibacterial barrier which inhibited catheter-associated urinary tract infection with no toxicity for at least 5 days. These in vivo studies suggest that this new catheter may be useful for controlling infection, with systemic and local safety, in patients undergoing short-term indwelling urethral catheterization.

Animals↗
PubMed2001

Enhancement of cephalosporin C production by cultivation of Cephalosporium acremonium M25 using a mixture of inocula.

AIMS: To enhance the productivity of Cephalosporin C (CPC) by cultivation of Cephalosporium acremonium M25 using a mixture of inocula. METHODS AND RESULTS: Inoculum age was classified into three stages (early, intermediate and late) by image analysis. A mixture of inocula, according to the inoculum ages, was used for efficient production of CPC in the main culture. The most effective mixing ratio of inocula for CPC production in shake flasks was a 3 : 7 volume ratio of early- and late-stage inocula. This was also the case in a 1.5 l stirred-tank reactor. CPC productivity was enhanced by about 32% and 34% when using an inoculum mixture in the shake flask and 1.5 l stirred-tank reactor, respectively. CONCLUSION: The morphological characteristics of C. acremonium M25 in the seed culture were quite different according to inoculum age. The compromise of different ages of inoculum showed better production of CPC. SIGNIFICANCE AND IMPACT OF THE STUDY: The productivity of CPC was enhanced considerably when using mixed inocula. The results of this study can be applied to fungal cultures for efficient production of various metabolites.

Acremonium↗
PubMed2001

Optimization of submerged culture conditions for the mycelial growth and exo-biopolymer production by Cordyceps militaris.

AIMS: The objective of the present study was to determine the optimal culture conditions for exo-biopolymer production by Cordyceps militaris in shake flask culture. METHODS AND RESULTS: The optimal temperature and initial pH for both mycelial growth and exo-biopolymer production by Cordyceps militaris in shake flask culture were found to be 20 degrees C and 6.0, respectively. Sucrose (40 g x l(-1)) and corn steep powder (10 g x l(-1)) were the most suitable carbon and nitrogen source for both mycelial growth and exo-biopolymer production. CONCLUSION: Under optimal culture conditions, the maximum exo-biopolymer concentration in a 5-l jar fermenter indicated 10.3 g x l(-1), which was approximately three times higher than that in shake flask culture. SIGNIFICANCE AND IMPACT OF THE STUDY: This process can have a significant impact on the industrial scale when sucrose and corn steep powder were used as carbon and nitrogen source.

Carbon↗
PubMed2001

Increased expression of atrial natriuretic peptide in the kidney of rats with bilateral ureteral obstruction.

BACKGROUND: Whether the postobstructive diuresis can be related to an altered regulation of local atrial natriuretic peptide (ANP) in the kidney was investigated. METHODS: Three groups of rats had both of their ureters obstructed for 48 hours. The kidneys were taken without releasing the obstruction in one group [bilateral ureteral obstruction (BUO)]. The obstruction was released in the other two groups and the animals were kept for 4 and 24 hours thereafter to collect urinary data (BUR-4 and BUR-24, respectively). Plasma and urine ANP levels were measured by radioimmunoassay. The mRNA expression of ANP, natriuretic peptide receptor-A (NPR-A), and NPR-C was determined by reverse transcription-polymerase chain reaction. ANP receptors were also quantitated by in vitro autoradiography. The activity of guanylyl cyclase was determined by the amount of cGMP generated in response to ANP. RESULTS: Urinary volume and sodium excretion increased in BUR-4, along with the ANP mRNA expression in the kidney and the urinary ANP excretion. The ANP excretion positively correlated with the urinary volume and sodium excretion. The mRNA expression of both NPR-A and NPR-C was decreased by BUO, the latter being far more prominently affected. The maximal binding capacity of radiolabeled ANP was decreased in the glomerulus and papilla in BUO. Not only the urinary parameters but also the mRNA expression of ANP, NPR-A, and NPR-C were comparable between BUR-24 and control rats. ANP-stimulated cGMP generation was reduced in the glomerulus and papilla in BUO animals, which was rapidly resumed following the release of the obstruction. CONCLUSIONS: Postobstructive diuresis may be due partially to an increased ANP activity in the kidney.

Animals↗
PubMed2001

Pelvic aspergillosis with tubo-ovarian abscess in a renal transplant recipient.

Common clinical manifestations of aspergillosis in renal transplant recipients are fever and pulmonary infiltrates, but involvement of the reproductive system is rare. We report a case of pelvic aspergillosis with tubo-ovarian abscess in a renal transplant patient. The patient received a cadaveric renal transplantation, and two episodes of acute rejection were treated with methylprednisolone pulse therapy. Surgical biopsy specimens of pelvic abscess detected by ultrasonogram and CT revealed Aspergillus. With amphotericin B treatment, the patient is well with normalization of erythrocyte sedimentation rate and C-reactive protein.

Abdominal Abscess↗
PubMed2001

The psychopharmacology of pathological gambling.

We discuss the rationale of the pharmacological approaches to pathological gambling and review the current status of drug treatments in this area. Specifically, we summarize the treatment study results of serotonin reuptake inhibitors, mood stabilizers, and opioid antagonists in pathological gambling. We also briefly describe the animal and human studies of other pharmacologic agents that show future promise in treating this disorder. Finally, we discuss a research agenda to be addressed in future drug treatment studies in pathological gambling.

Clinical Trials as Topic↗
PubMed2001

Amphotericin B decreases adenylyl cyclase activity and aquaporin-2 expression in rat kidney.

The present study was intended to examine whether the amphotericin-induced urinary concentration defect can be related to an altered regulation of aquaporin (AQP) water channels in the kidney. Male Sprague-Dawley rats were injected with amphotericin B (6 mg/kg/d, IP ) for 21 days. The protein expression of AQP1-3, Gsalpha, and adenylyl cyclase was determined in the kidney. To further specify the primary point of dysregulation of AQP channels that are activated by the arginine vasopressin/cyclic adenosine monophosphate (AVP/cAMP) pathway, different components of adenylyl cyclase complex were separately examined for their cAMP-generating activities. Amphotericin treatment resulted in kidney failure associated with decreased tubular water reabsorption and increased urinary flow rate. The expression of AQP2 proteins was significantly decreased in the outer medulla and inner medulla but not in the cortex. The expression of AQP2 proteins in the membrane fraction changed in parallel with that in the cytoplasmic fraction, suggesting a preserved targeting. Neither the expression of AQP1 nor that of AQP3 was significantly affected in the cortex, outer medulla, or inner medulla. The cAMP generation in response to AVP or sodium fluoride was decreased, whereas that to forskolin was not significantly altered. The expression of Gsalpha proteins was decreased in the inner medulla, whereas that of adenylyl cyclase VI remained unaltered. These findings indicate that the amphotericin-induced urinary concentration defect may in part be causally related to a reduced abundance of AQP2 channels in the kidney. It is also suggested that the primary impairment in the pathway leading to the activation of AQP channels that are regulated by the AVP/cAMP pathway lies at the level of G proteins.

Adenylyl Cyclases↗
PubMed2001

Increased expression of atrial natriuretic peptide in ureteral obstructed kidneys in rats.

OBJECTIVES: Whether the natriuresis in the previously ureteral obstructed kidney may be related to an altered regulation of local atrial natriuretic peptide (ANP) was investigated. MATERIALS AND METHODS: Male Sprague-Dawley rats were unilaterally obstructed of the left ureters for 48 hours. The left and right ureters were separately cannulated to collect urine samples. In some rats, both kidneys were removed without releasing the obstruction. Control rats were treated the same except that no ureteral obstruction was made. The mRNA expression of ANP and natriuretic peptide receptor (NPR)-A was determined in the kidney by reverse transcription-polymerase chain reaction. The guanylyl cyclase activity was measured by the amount of cGMP generated in response to ANP. Plasma levels of ANP were measured by radioimmunoassay. RESULTS: The ureteral obstruction did not significantly affect the plasma ANP levels. In the obstructed kidney, the creatinine clearance was decreased, while the fractional excretion of sodium increased. The expression of ANP mRNA was increased in the obstructed kidney. The NPR-A mRNA expression was not altered in the glomerulus, but was decreased in the papilla of the obstructed kidney. Nor was the guanylyl cyclase activity in the glomerulus altered. Although the guanylyl cyclase activity in the papilla was significantly decreased in the obstructed kidney, it was rapidly resumed upon releasing the obstruction. CONCLUSIONS: An increased local expression of ANP may, at least in part, account for the natriuresis in the previously ureteral obstructed kidney.

Animals↗
PubMed2001

The effect of zinc-crystallized glucagon-like peptide-1 on insulin secretion of macroencapsulated pancreatic islets.

This research investigates the use of an insulinotropic factor, glucagon-like peptide-1 (GLP-1), to enhance insulin secretion from islets within a macrocapsule. A zinc-crystallized form of GLP-1 was added to the macrocapsule device to have a longer and more controlled release of the bioactive monomer GLP-1. The type of macrocapsule device used for this study consisted of a hollow fiber (MWCO 100,000 and 1 mm inner diameter) containing rat islets and GLP-1 crystals within a poly(N-isopropylacrylamide-co-acrylic acid) (2 mol% acrylic acid) matrix. When incubating the system in media with a high glucose concentration (300 mg/dL), insulin secretion was enhanced with a >85% increase after an induction period. When the same type of system was used in a dynamic perfusion experiment, similar results were obtained. GLP-1 crystals can be an effective form to be entrapped in a bioartificial pancreas to enhance insulin secretion function, especially at high glucose concentrations.

Animals↗
PubMed2001

Sensate sole-to-sole reconstruction using the combined medial plantar and medialis pedis free flap.

The coverage of soft-tissue defects of the sole needs special consideration because of the forces of weight bearing on the reconstruction. A variety of free tissue transfers have been advocated for soft-tissue replacement of the weight-bearing portions. However, there is no doubt that the ideal tissue for resurfacing the sole is the plantar tissue itself. The authors present a case of reconstructing the sole with the combined medial plantar and medialis pedis free flap that involves approximately 70% of the weight-bearing portion. This contralateral, combined fasciocutaneous free flap based on the posterior tibial-medial plantar vascular system is a good alternative in covering extensive sole injuries.

Adolescent↗
PubMed2001

An open naltrexone treatment study in pathological gambling disorder.

The present study was designed to test the short-term efficacy and safety of naltrexone in the treatment of pathological gambling disorder. Seventeen subjects (seven men, 10 women) who fulfilled DSM-IV criteria for pathological gambling disorder, and were free from other Axis I diagnoses by Structured Clinical Interview for DSM-III-R screening, participated in a 6-week open naltrexone flexible dose trial. Gambling symptom change was assessed with the patient-rated Clinical Global Impression (CGI) Scale, the clinician-rated CGI and the Gambling Symptom Assessment Scale. Side-effects were monitored weekly and liver function tests biweekly. Naltrexone reduced urges to gamble and gambling behaviour. The mean change in gambling frequency per week was 1.40 +/- 0.28 episodes per week; the mean change in dollars lost per week was $66.95 +/- 13.77; and the mean change in clinician-rated CGI Improvement was 0.40 +/- 0.04. Of those who responded to the medication, the majority had done so by the end of the fourth week. Men responded to naltrexone as well as women. The average naltrexone dose required for effective symptom control was 157 mg/day. Nausea was common during the first week (47%). The present findings provide evidence that naltrexone may be effective in the treatment of pathological gambling disorder. The present report is preliminary and controlled trials are needed to confirm these findings.

Adolescent↗
PubMed2001

Synthetic phytoceramides induce apoptosis with higher potency than ceramides.

Ceramides are naturally occurring compounds recognized to mediate apoptosis. N-acylsphingosines, containing a double bond at carbons 4 and 5 of their sphingoid backbone, are thought to be the active form, because N-acylsphinganines with completely saturated sphingoid are inactive. In the present study, we synthesized a series of N-acyl-4D-ribo-phytosphingosines (phytoceramides) that contain a hydroxyl group at carbon 4 and investigated structure-cytotoxicity relationship of the presumed functional groups in ceramides. N-Acetylphytoceramide (PCer2) and N-hexanoylphytoceramide (PCer6) were found to be more cytotoxic than ceramides as determined by released lactate dehydrogenase activity and morphological criteria. This was not caused by intracellular conversion of phytoceramides to ceramides, because no N-hexanoylsphingosine was formed after incubation of cell lysate with PCer6. Among phytoceramides having acyl chains two to eight carbons long, the cytotoxicity was highest with five or six carbons. The carbonyl group of the amide bond did not seem to be critical, because substitution of the oxygen with sulfur did not influence the cytotoxicity. The phytoceramide-induced cell death was observed to be apoptotic in nature with the use of terminal deoxynucleotidyl transferase dUTP nick-end labeling and propidium iodide staining. Because phytoceramides can be readily synthesized from yeast sources, they may present a potential and economical alternative to ceramide in future studies and therapies.

Antineoplastic Agents↗
PubMed2001

Microtubule- and dynein-mediated movement of Orientia tsutsugamushi to the microtubule organizing center.

The host cell microfilaments and microtubules (MTs) are known to play a critical role in the life cycles of several pathogenic intracellular microbes by providing for successful invasion and promoting movement of the pathogen once inside the host cell cytoplasm. Orientia tsutsugamushi, an obligate intracellular bacterium, enters host cells by induced phagocytosis, escapes to the cytosol, and then replicates in the cytosol. ECV304 cells infected with O. tsutsugamushi revealed the colocalization of the MT organizing center (MTOC) and cytosolic orientiae by indirect immunofluorescence assay. Using immunofluorescence microscopy in the presence and absence of MT-depolymerizing agents (colchicine and nocodazole), it was shown that the cytosolic oriential movement was mediated by MTs. By transfection study (overexpression of dynamitin [also called p50], which is known to associate with dynein-dependent movement), the movement of O. tsutsugamushi to the MTOC was also mediated by dynein, the minus-end-directed MT-related motor. Although the significance of this movement in the life cycle of O. tsutsugamushi was not proven, we propose that the cytosolic O. tsutsugamushi bacteria use MTs and dyneins to propel themselves from the cell periphery to the MTOC.

Cell Line↗
PubMed2001

Diagnostic value of serum IGF-I and IGFBP-3 in growth hormone disorders in adults.

OBJECTIVE: To investigate the diagnostic value of serum insulin-like growth factor-I (IGF-I) and insulin-like growth factor-binding protein-3 (IGFBP-3) measurements in adult patients with acromegaly and GH deficiency (GHD). METHODS: Serum IGF-I and IGFBP-3 levels were measured in 39 active acromegalic patients, 34 adult patients with GHD and 150 healthy adults. Disease activity in patients with acromegaly was confirmed by nadir GH levels during an oral glucose tolerance test (OGTT). Among patients with acromegaly, 15 had not been treated previously and 24 had been treated but not cured. GHD in adults was diagnosed by an insulin tolerance test (ITT). Among patients with GHD, 15 were aged 20-40 years (9 men and 6 women) and 19 were aged over 40 years (9 men and 10 women). One hundred and fifty healthy subjects were recruited as a control group. To compare the individual serum IGF-I and IGFBP-3 levels of patients with the results of the gold standard, we calculated age- and sex-corrected standard deviation scores (SDS) for individual IGF-I and IGFBP-3 levels. The sensitivities of serum IGF-I and IGFBP-3 measurements for the disease diagnosis were analyzed using the mean +/- 2 SD of the values of healthy control subjects as a diagnostic cutoff, defining 95% specificity. RESULTS: The mean IGF-I and IGFBP-3 SDS levels were significantly higher in active acromegalic patients, both untreated and treated but not cured, than in the control subjects (p < 0.05). The sensitivities of serum IGF-I and IGFBP-3 measurements for the diagnosis of acromegaly were 97.4 and 81.8%, respectively. In untreated patients with acromegaly, the sensitivities of serum IGF-I and IGFBP-3 measurements for the diagnosis of disease were 100 and 100%, while these were 95.8 and 72.7% in treated patients with acromegaly. In adult patients with GHD, the mean IGF-I and IGFBP-3 SDS were significantly lower than those of the control subjects (IGF-I, -2.2 +/- 0.8 vs. 0.0 +/- 1.0 SDS, p < 0.0001); IGFBP-3, -1.7 +/- 1.2 vs. 0.0 +/- 1.0 SDS, p < 0.0001), but there was a considerable overlap between GHD in adults and the controls. In all patients with GHD, the sensitivities of serum IGF-I and IGFBP-3 measurements were 64.7 and 52.9%, respectively. In the group of women aged 20-40 years, the sensitivity of IGF-I measurement for the diagnosis of GHD was 100%, although the number of patients was only 6. CONCLUSION: Both serum IGF-I and IGFBP-3 measurements are comparable to an oral glucose tolerance test in patients with untreated acromegaly, but in acromegalic patients that have undergone surgery and/or radiotherapy, serum IGF-I is more valuable for determining disease activity than serum IGFBP-3. Serum IGF-I and IGFBP-3 measurements are not valuable for the diagnosis of GHD in adults, but in women aged 20-40 years serum IGF-I measurement appears to be useful in the diagnosis of GHD.

Acromegaly↗
PubMed2001

The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue.

Type 2 iodothyronine deiodinase (D2) is a selenoenzyme, the product of the recently cloned cAMP-dependent Dio2 gene, which increases 10- to 50-fold during cold stress only in brown adipose tissue (BAT). Here we report that despite a normal plasma 3,5,3'-triiodothyronine (T3) concentration, cold-exposed mice with targeted disruption of the Dio2 gene (Dio2(-/-)) become hypothermic due to impaired BAT thermogenesis and survive by compensatory shivering with consequent acute weight loss. This occurs despite normal basal mitochondrial uncoupling protein 1 (UCP1) concentration. In Dio2(-/-) brown adipocytes, the acute norepinephrine-, CL316,243-, or forskolin-induced increases in lipolysis, UCP1 mRNA, and O(2) consumption are all reduced due to impaired cAMP generation. These hypothyroid-like abnormalities are completely reversed by a single injection of T3 14 hours earlier. Recent studies suggest that UCP1 is primarily dependent on thyroid hormone receptor beta (TR beta) while the normal sympathetic response of brown adipocytes requires TR alpha. Intracellularly generated T3 may be required to saturate the TR alpha, which has an approximately fourfold lower T3-binding affinity than does TR beta. Thus, D2 is an essential component in the thyroid-sympathetic synergism required for thermal homeostasis in small mammals.

Adipose Tissue, Brown↗