Biomedical subjects

Sang Won Han

Publications and source records attributed to Sang Won Han.

25 records · Page 2Linked to original sources

PubMed2004

Intravesical electrical stimulation improves neurogenic bowel dysfunction in children with spina bifida.

PURPOSE: We observed concomitant improvement in fecal incontinence in children with myelomeningocele undergoing intravesical electrical stimulation (IVES) to decrease uninhibited bladder contractions and increase bladder capacity and/or bladder sensation. We retrospectively reviewed the effect of intravesical electrical stimulation on neurogenic bowel dysfunction in these children. MATERIALS AND METHODS: A total of 9 boys and 15 girls 3.9 to 13.2 years old (mean age 8.1) completed a mean of 30.3 daily sessions (range 10 to 69) of IVES. Evaluation forms were used to record frequency of fecal incontinence, daily bowel movement and diaper use before and after IVES. RESULTS: The mean number of overall fecal incontinence episodes decreased significantly from 7.36 to 4.8 a week after IVES (p <0.05). Greater than 50% decrease in the episodes of fecal incontinence was observed in 75% of the patients. However, there was no significant change in the number of daily bowel movements before (1.8 daily) and after (1.55 daily) IVES. CONCLUSIONS: These results demonstrate the therapeutic effect of IVES in children with neurogenic bowel dysfunction and spina bifida. We believe that IVES is another viable option for controlling fecal incontinence in these children.

Adolescent↗

PubMed2004

Structural evidence against hormonal therapy for cryptorchid testis: abnormal gubernacular attachment.

PURPOSE: Various factors are involved in testicular descent, and no single factor is elucidated as the cause of cryptorchidism. We prospectively observed the locations of gubernacular attachments in the cryptorchid testis. MATERIALS AND METHODS: From April 1996 to June 2002, 639 boys underwent surgical correction of cryptorchid testis. Those with complete records of testicular locations and gubernacular attachments were analyzed. RESULTS: A total of 639 boys underwent 732 surgical corrections of inguinal testis (425, 58%), high scrotal testis (165, 23%) and impalpable abdominal testis (142, 19%). Impalpable abdominal testes had gubernacular attachment to either the lateral or upper scrotum in 36 cases (25%) or around the inguinal ring in 83 (58%). The gubernaculum was attached to the bottom of the scrotum in 21 inguinal testes (5%), to the lateral or upper scrotum in 132 (31%) or around the inguinal ring in 268 (63%). In cases of high scrotal testis the gubernaculum was attached usually to the bottom of the scrotum (28, 17%), to the lateral or upper scrotum (109, 66%) or around the inguinal ring (26, 16%). CONCLUSIONS: The locations of distal gubernacular attachments in the cryptorchid testis were usually abnormal (93%). In these cases the possible testicular descent induced by hormonal therapy may either be insufficient or unable to prevent future ascent. Thus, early surgical correction rather than hormonal therapy is warranted in boys with cryptorchid testis.

Child↗

PubMed2004

Increased nephron volume is not a cause of supranormal renographic differential renal function in patients with ureteropelvic junction obstruction.

PURPOSE: Increasing clinical importance is being placed on the role of differential renal function (DRF) in the management of congenital ureteropelvic junction obstruction. Supranormal DRF of the hydronephrotic kidney on renal scan is a puzzling phenomenon and is hypothesized to be due to an increase in single nephron filtration or nephron volume without sound evidence. We studied the histopathological changes of hydronephrotic kidneys to determine whether glomerular hypertrophy underlies supranormal DRF. MATERIALS AND METHODS: We retrospectively evaluated the records of 3 females and 32 males with unilateral congenital hydronephrosis who underwent pyeloplasty. Mean patient age at operation was 12.6 months (range 0.1 to 144). Needle biopsies from 3 different sites at the lower pole of the kidney were performed during surgery. To evaluate the presence of glomerular hypertrophy, the maximal planar area of glomeruli was measured under light microscopy using an image analyzer. Tissue samples obtained from kidneys without a history of urinary tract disease at autopsy were used as controls. The mean glomerular areas of the patient and control groups were evaluated according to DRF and age. RESULTS: The mean glomerular area values of the patient group were smaller than those of the control group, except for 4 patients. The glomerular areas of the hydronephrotic kidneys with supranormal DRF were not significantly different from those of the control group. Instead, the probability of larger renal glomeruli increased with decreasing DRF (p = 0.1155). CONCLUSIONS: Increased nephron volume can be discounted as a cause of supranormal DRF.

Biopsy↗

PubMed2003

Methylation status of promoters and expression of MUC2 and MUC5AC mucins in pancreatic cancer cells.

Anomalous expression of certain types of mucins occurs in pancreatic tumors, but little is known about the causes. MUC2 and MUC5AC are not expressed in normal pancreas. In the present study an immunohistochemical screening showed that MUC2 antigen was expressed in 6% of invasive tumors. Of the pancreatic cell lines, 2.4% expressed MUC2 message and antigen. In contrast, MUC5AC antigen was expressed in 86-100% of invasive adenocarcinoma (depending on the antibody). MUC5AC message and antigen were expressed in 66.7% of the cell lines tested. A polymerase chain reaction based assay was used to determine if methylation of CpG sites immediately 5' of the transcription initiation sites of the MUC2 and MUC5AC genes could be related to mucin expression in the cell lines. Digestibility by the methylation sensitive restriction enzyme HpaII correlated with the presence or absence of mRNA in 100% and 77.8% of the cell lines for MUC2 and MUC5AC, respectively. Treatment of a cell line that did not express MUC2 or MUC5AC gene products with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine resulted in an increase in MUC2 message but no change in MUC5AC message. In summary, the expression of MUC2 gene products correlated well with methylation of the proximal region of the promoter whereas expression of MUC5AC may involve additional regions or other mechanisms.

Adenocarcinoma↗

PubMed2002

Mutational analyses of the signals involved in the subcellular location of DSCR1.

BACKGROUND: Down syndrome is the most frequent genetic disorder in humans. Rare cases involving partial trisomy of chromosome 21 allowed a small chromosomal region common to all carriers, called Down Syndrome Critical Region (DSCR), to be determined. The DSCR1 gene was identified in this region and is expressed preferentially in the brain, heart and skeletal muscle. Recent studies have shown that DSCR1 belongs to a family of proteins that binds and inhibits calcineurin, a serine-threonine phosphatase. The work reported on herein consisted of a study of the subcellular location of DSCR1 and DSCR1-mutated forms by fusion with a green fluorescent protein, using various cell lines, including human. RESULTS: The protein's location was preferentially nuclear, independently of the isoform, cell line and insertion in the GFP's N- or C-terminal. A segment in the C-terminal, which is important in the location of the protein, was identified by deletion. On the other hand, site-directed mutational analyses have indicated the involvement of some serine and threonine residues in this event. CONCLUSION: In this paper, we discuss the identification of amino acids which can be important for subcellular location of DSCR1. The involvement of residues that are prone to phosphorylation suggests that the location and function of DSCR1 may be regulated by kinases and/or phosphatases.

Amino Acid Motifs↗

PubMed2002

Cellular proliferation during compensatory renal growth in neonatal rats using flow cytometry.

BACKGROUND: Compensatory renal growth consists of cellular enlargement and a small but consistent increase in DNA content. It has been assumed that the increase in the total renal DNA content was due to new cell formation. METHODS: To test the hypothesis of whether cellular hyperplasia is the cause of the compensatory renal growth after the loss of the renal parenchyma and the timing of the DNA increase in neonatal rats, we performed cell cycle analysis using flow cytometry. RESULTS: Following unilateral nephrectomy, the maximum increases of neonatal cortical cells entering the S phase occurred at 72 and 120 h (9.4 and 9.6% compared to 7.0 and 6.1% of the sham-operated group). Peak increases of neonatal kidney cortical cells entering the G2M phase occurred at 48 and 72 h (4.3 and 4.6% compared to 3.3 and 3.9% of the sham-operated group). CONCLUSION: DNA synthesis and replication occurs during compensatory renal growth following unilateral nephrectomy in neonatal rats as evidenced by an increase in cells entering both the S and G2M phases. In neonatal rats these events appear to be completed within 48-120 h after nephrectomy.

Animals↗

PubMed2002

Sensory neuronal change after intravesical electrical stimulation in spinailized rat.

The clinical benefits of intravesical electrical stimulation (IVES) in patients with increased residual urine or reduced bladder capacity have been reported. However, studies on the underlying mechanism of IVES has been limited to the Adelta afferent and parasympathetic neurons. This study investigated the changes in the calcitonin gene-related peptide (CGRP), substance P (SP), and nitric oxide synthase (NOS) expression in the thoracolumbar and lumbosacral dorsal root ganglia (DRG) of spinalized rats to determine the effect of IVES on the C fiber afferent nerve. Forty Sprague-Dawley rats were divided into normal controls (n=10); IVES treated normal rats (n=10), spinalized rats (n=10), and IVES treated spinalized rats (n=10). IVES was performed for 2 weeks (5 days a week). IVES was started 3 weeks after spinalization in the spinalized animals. All animals had the DRG removed at the thoracolumbar (T13-L2) and lumbosacral (L5-S1) level. Changes in the CGRP, SP and n-NOS levels at the DRG were measured by western-blot analysis. The relative density of the CGRP and SP following spinalization was significantly higher compared to the controls in both the T13-L2 and L5-S1 DRG. However, IVES in the spinalized rat significantly decreased the relative density of the CGRP and SP compared to the rats with spinalization alone. A significant increase in the relative density of n-NOS was detected in the L5-S1 DRG following spinalization. However, the density of n-NOS was significantly lower after IVES in both the T13-L2 and L5-S1 DRGs. In conclusion, IVES significantly reduced the CGRP, SP and n-NOS levels in the DRG of spinalized rats. CGRP, SP and n-NOS are the main factors that contribute to the hyperexcitability of the micturition reflex after spinal cord injury. These results suggest that the bladder C fiber afferent is also involved in modulating the micturition reflex by IVES.

Animals↗