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Biomedical subjects

S K Choi

Publications and source records attributed to S K Choi.

At least 109 records · Page 6Linked to original sources
PubMed1993

Transdermal dihydrotestosterone therapy and its effects on patients with microphallus.

To investigate the efficacy of transdermal dihydrotestosterone therapy on 22 patients with microphallus, we applied dihydrotestosterone gel for 8 weeks to the external genitalia at daily doses of 12.5 mg. and 25 mg. for ages less than and older than 10 years, respectively. All patients were evaluated for penile and prostatic growth, pituitary-gonadal axis function, serum sex hormone binding globulin, lipid metabolism, hepatotoxicity, bone age and height velocity. All patients demonstrated growth of the penis during treatment. The mean increase rate (153%) in the first 4 weeks of treatment was higher than that (118%) of the second 4 weeks. Of importance is that responses were noted in 4 patients who had failed testosterone therapy for microphallus. The pituitary-gonadal axis was transiently suppressed during treatment, and serum sex hormone binding globulin and lipid metabolism were transiently affected during treatment. Serum alkaline phosphatase increased, mainly due to change of bone isoenzyme but bone ages and mean height velocity were not significantly affected. In conclusion, transdermal dihydrotestosterone therapy is an effective and relatively safe modality in the treatment of microphallus.

Administration, Cutaneous↗
PubMed1993

Trephination with vacuum trephine in undercorrection of myopic epikeratoplasty.

For the treatment of undercorrection after myopic epikeratoplasty, early suture removal, scar revision, retrephination, replacement of lenticule and, recently, excimer laser photorefractive keratoplasty have been employed. We performed trephination with Hessburg-Barron vacuum trephine on 11 eyes of 11 patients whose post-epikeratoplasty myopic power was over -4.00 diopters for 3 consecutive months. Patients were followed up on post-trephination 1 month, 3 months and 6 months. The mean duration from epikeratoplasty to trephination was 14.27 months, the mean pre-trephination spherical equivalent was -8.50 D and the mean keratometric reading was 40.87 D. The mean reduction of spherical equivalent was -4.07, -5.99, -8.02 D at post-trephination 1, 3, 6 months, respectively. The mean keratometric reading was 37.60 diopters at 1 month and 41.53 diopters at 6 months. At 1 and 3 months, there were significant reductions of myopic power in refraction and keratometry (p < 0.01), but, at 6 months, regression to pre-trephination levels took place (p > 0.05). There was no change of uncorrected and best corrected visual acuity between baseline and post-trephination 6 months.

Adult↗
PubMed1993

Silicone oil keratopathy.

Light microscopy and electron microscopic examination were carried out on the corneal buttons of two patients who required penetrating keratoplasty for treatment of corneal complication following the intraocular injection of silicone oil to repair recurrent retinal detachments in aphakic eyes. Light microscopic examination demonstrated increased cellularity and irregularity of collagen fibers of stromal layer, defect of endothelial cell layer and endothelial degeneration. Electron microscopy examination demonstrated marked decrease in endothelial cell population density, accompanied by flattening and thinning of the remaining cells and attenuation of cell borders. There were silicone droplets in the endothelial cell layer and collagenous layer posterior to endothelial layer. These findings are well correlated to clinical manifestation and are thought to be rather due to barrier effect of silicone oil than direct toxicity.

Adult↗
PubMed1993

Selective antagonism of native and cloned kainate and NMDA receptors by polyamine-containing toxins.

Antagonism of rat excitatory amino acid receptors by a synthetic analog [philanthotoxin-343 (PhTX-343)] of a polyamine amide, wasp toxin (philanthotoxin-433) and a structurally related spider toxin, argiotoxin-636 (ArgTX-636), was examined in Xenopus oocytes injected with rat brain RNA or RNA transcribed from the excitatory amino acid receptor clones GluR1, GluR2 and NMDAR1. Antagonism of both kainate- and N-methyl-D-aspartate (NMDA)-elicited responses by PhTX-343 and ArgTX-636 was reversible, noncompetitive and partly voltage-dependent. Dose-inhibition curves were constructed using EC50 concentrations of kainate (100 microM) and N-methyl-D-aspartate (33 microM) in the presence of variable concentrations of ArgTX-636 and PhTX-343. In oocytes injected with rat brain RNA, IC50s for antagonism of kainate-induced currents were similar, i.e., 0.07 microM and 0.12 microM for ArgTX-636 and PhTX-343, respectively, whereas IC50s for antagonism of NMDA-induced currents were dissimilar, i.e., 0.04 microM for ArgTX-636 and 2.5 microM for PhTX-343. In oocytes expressing NMDAR1, IC50s were similar to those for the antagonism of NMDA-induced currents of oocytes injected with rat brain RNA. PhTX-343 and ArgTX-636 were more or less equally potent (IC50s were 2.8 microM and 3.4 microM, respectively) antagonists of the response of GluR1 to 100 microM kainate. However, GluR1 was approximately 50 times less sensitive to the toxins than non-N-methyl-D-aspartate receptors expressed in oocytes injected with rat brain RNA. Receptors co-expressed from GluR1 + GluR2 were virtually insensitive to PhTX-343 (IC50 = 270 microM) and to ArgTX-343 (IC50 approximately 300 microM).

Animals↗
PubMed1992

Rapid expansion of hypertensive intracerebral hemorrhage.

We report a series of 10 patients who had a rapid expansion of a hypertensive intracerebral hemorrhage (HICH). It occurred in approximately 3% of 320 patients who sought treatment for HICH during the past 2 years. The site of hemorrhage was the putamen in 6 patients and the thalamus in 4 patients. Neurological deterioration occurred in a mean time of 40 hours after the onset of symptoms (range, 5.5-109 h). Fifty percent of all patients deteriorated within 24 hours. Persistent hypertension was recorded in all patients. Repeat computed tomography showed an increase of hematoma volume that was twice as large in thalamic hemorrhage and about three times as large in putaminal hemorrhage. Six patients died, whereas 3 survived with severe disability and 1 survived with moderate disability. This study indicates that continued or subsequent bleeding can occur in HICH. If those lesions are not detected early and microsurgically evacuated, they are almost always fatal. Early stereotactic evacuation with urokinase irrigation is considered more dangerous than open craniotomy by microsurgical techniques. We stress the need for attention to this problem during the acute phase of HICH.

Adult↗
PubMed1991

Autoradiographic and immunohistochemical study on the proliferative kinetics of intestinal metaplasia.

In order to elucidate the proliferative behavior of the intestinal metaplasia around gastric cancer, the authors used both in vitro tritiated thymidine (3H-thymidine) autoradiography and in vivo bromodeoxyuridine (BrdUrd) immunohistochemistry for labeling the proliferative cells of the normal pyloric glands and metaplastic gastric glands. The results of the methods were comparable: The labeling pattern and the rate of labeling were very similar. In the normal pyloric mucosa, the labeled cells were confined to the isthmus region, indicating that pyloric glandular cells are normally renewed from the isthmus region. On the other hand, a zone of the labeled cells was found in the lower half of the intestinalized mucosa, indicating that cell proliferation took place deep in the mucosa, just like the case of normal intestinal glands. The labeling indices of the pyloric mucosa were 19.4% by autoradiography and 18.0% by immunohistochemistry, and that of the intestinalized gastric glands were 25.2% by autoradiography and 24.2% by immunohistochemistry. In conclusion, both 3H-thymidine autoradiography and BrdUrd immunohistochemistry showed that the proliferative kinetics of the intestinalized gastric glands was similar to that of the normal intestinal glands rather than the pyloric glands, i.e. a lower level of proliferative zone and higher labeling index were present.

Aged↗
PubMed1990

MR imaging in hypertrophic neuropathy: a case of hereditary motor and sensory neuropathy, type I (Charcot-Marie-Tooth).

We describe findings of Charcot-Marie-Tooth disease in magnetic resonance imaging (MRI). The MRI examination of the lumbar spine with and without gadolinium DTPA showed diffusely enlarged cauda equina, nerve roots, and ganglia. In the setting of appropriate family history and clinical presentation, the findings of diffusely enlarged nerve roots support the diagnosis of hereditary motor and sensory neuropathy, Type I (HMSN I, Charcot-Marie-Tooth).

Adult↗
PubMed1989

A survey of externally recognizable genitourinary anomalies in Korean newborns. Korean Urological Association.

To estimate the incidence of externally recognizable genitourinary anomalies and associated anomalies in the newborns in Korea, retrospective and prospective studies have been performed. Thirty eight of 48 urology training hospitals participated in this nationwide survey. In this study we have included minor defects or variations in the anomaly to evaluate the incidence of the recognizable genitourinary conditions in the newborns. The incidence of genitourinary anomaly in 1,000 newborn delivery in a year was 11.0 in the prospective study and this figure is about three times higher than the retrospective study and is considered to be close to the true incidence. The incidence of genitourinary anomaly in 1,000 male newborn was 20.4. Hydrocele, cryptorchidism and hypospadias were most commonly observed. The incidence of hydrocele in 1,000 male newborn was 9.89 and the incidence of cryptorchidism was 7.26 and the incidence of hypospadias was 2.13. The incidence of associated anomaly in 100 genitourinary anomaly was 7.9. Congenital heart diseases and anorectal anomalies were commonly associated anomalies. In the newborns with genitourinary anomalies, premature infants account larger portion than is usually reported in total delivery.

Birth Weight↗
PubMed1989

Early gastric cancer in Korea.

We reviewed the 639 cases of early gastric cancer from nation-wide 16 medical centers. The proportion of early gastric cancer among surgically resected gastric carcinoma comprised 6 to 12 percent. Male to female ratio was 1.7 to 1 with male preponderance. Mean ages of the early gastric cancer was 49.0 years and most prevalent ages was 5th decade. Macroscopically type IIc was most prevalent, reaching 59.9 percent. Depressed type lesions was more frequent than elevated type lesions by four folds. The size of lesions less than 4 cm accounted for more than 80 percent. Most frequent site of lesions were lower third by the CMA classification and lesser curvature transectionally. Lymph node metastasis was observed in 10.9 percent of all cases and it was more frequent in large tumor size more than 4 cm, elevated type, and undifferentiated carcinoma. 5-year survival rate was 91.6 percent. Gastrofiberscopic examination was superior to that of radiological examination in the diagnosis of early gastric cancer.

Adult↗
PubMed1988

Clinical features of Crohn's disease in Korea.

Crohn's disease is a rare disease in Korea, and only 45 cases have been reported during the period of 34 years from 1952 to 1985. The male to female ratio was about 1.3 to 1 with a slight preponderance of males. The age at diagnosis ranged from 8 to 72 (mean 35.5) years, and the peak incidence occurred in the 3rd, 4th and 5th decades and declined thereafter. More than two thirds of the cases had a grossly demonstrable lesion involving the small bowel, including the terminal ileum. The proportion of patients with macroscopic disease continued to the large bowel alone was only 15%. Abdominal pain was common, presenting in 89% of the patients, while such symptoms as fever, hematochezia and diarrhea were not common. Abdominal mass was palpable in more than half the cases, which made it difficult to differentiate Crohn's disease from cancer of the colon, especially in cases with a predominant infiltration of the bowel wall and a secondary ulcer formation. That is one of the reasons why most cases in Korea have been reported by surgeons. A wide variety of complications were present, of which small bowel obstruction was the most common. Other complications were free perforation, malnutrition, fistula formation, hemorrhage and abscess formation, in decreasing order. The incidence of symptomatic perianal disease was only 11%, and this might be due to the small proportion of the disease confined to large bowel. Extraintestinal manifestations were also rare, and only three patients presented symptoms of arthritis. Other systemic features such as liver disease, skin lesion, eye complications were absent.

Adolescent↗
PubMed1987

Risk stratification in perforated duodenal ulcers. A prospective validation of predictive factors.

In order to validate a previously derived set of risk factors, 259 consecutive patients who had simple closure or definitive operation for perforated duodenal ulcers were studied prospectively. Major medical illness, preoperative shock, and longstanding perforation (more than 24 hours) correctly predicted the outcome in 93.8% of patients. Most importantly, 16 patients (6.2%) who died after operation could be identified (no false-negative error). The mortality rate increased progressively with increasing numbers of risk factors: 0%, 10%, 45.5%, and 100% in patients with none, one, two, and all three risk factors, respectively. These findings underscore the importance of patient selection and the feasibility of a risk grading system in guiding surgical management. Definitive surgery can be done safely in good-risk patients. Simple closure is preferable in those patients with uncomplicated perforations if any risk factor is present. Truncal vagotomy and drainage may be required if there is coexisting bleeding or stenosis. Nonoperative treatment deserves re-evaluation in patients with all three risk factors because of their uniformly dismal outcome after operation.

Adult↗
PubMed1986

Arachnoid cyst of the collicular cistern.

Arachnoid cysts of the collicular cistern are rare. Two patients with this lesion are reported in whom the extent and location of the cyst were shown by computed tomography. The clinical and radiographic features of this lesion are summarized.

Adolescent↗
PubMed1986

Prostaglandin E1 (misoprostol) overcomes the adverse effect of chronic cigarette smoking on duodenal ulcer healing.

Chronic cigarette smoking adversely affects duodenal ulcer healing despite treatment by potent gastric acid-reducing agents. Prostaglandins of the E series possess antisecretory and cytoprotective properties and theoretically offer advantages over existing therapeutic agents. A double-blind randomized study was performed to compare complete duodenal ulcer healing as assessed by endoscopies every two weeks for up to 12 weeks. Two hundred twenty-nine patients were randomized to receive misoprostol, an orally stable synthetic derivative of prostaglandin E1, in 200-micrograms or 300-micrograms qid dosages, or placebo. Life-table analysis showed that (1) both regimens of misoprostol were significantly more effective than placebo, achieving healing rates of 61% and 71%, respectively, at four weeks, and (2) cigarette smoking significantly impaired healing by placebo but not by misoprostol. In fact, the time-healing curves of smokers and nonsmokers on the higher dose of misoprostol completely overlapped. Furthermore, delayed treatment and large ulcer diameter adversely affected healing by misoprostol in smokers, whereas in nonsmokers, high basal and maximal acid output were unfavorable. Misoprostol is recommended for the treatment of duodenal ulcer, particularly in chronic smokers early in a given period of symptoms.

Adult↗