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Biomedical subjects

S S Choi

Publications and source records attributed to S S Choi.

At least 55 records · Page 3Linked to original sources
PubMed1995

The radial sensory nerve entrapped between the two slips of a split brachioradialis tendon: a rare aspect of Wartenberg's syndrome.

A retrospective study was designed to verify how often an anatomic variation caused the radial sensory nerve entrapment at the forearm (Wartenberg's syndrome). This variation, in which the superficial branch of the radial nerve emerges from under the fascia between two slips of a split brachioradialis tendon, was mentioned once in a clinical textbook as a basis for nerve entrapment but was found to occur in 5 of 150 dissected arms in 4 of 75 cadavers (3.3% of the investigated arms) in a recent anatomic study. To evaluate the incidence of this variation, 143 operative reports from patients who had Wartenberg's syndrome were reviewed. The variation was observed in seven patients. We conclude that any operation for Wartenberg's syndrome should include a thorough investigation of the site where the radial sensory nerve emerges from under the fascia and, if the nerve emerges through a split brachioradialis tendon, the anomalous tendon slip should be divided.

Forearm↗
PubMed1995

Intracranial complications of sinusitis in childhood.

Complications of sinusitis in children, such as intracranial abscess formation, are uncommon and are often clinically unremarkable in comparison to similar disease processes in adults. Between 1983 and 1991, 443 children were admitted to Children's National Medical Center in Washington, DC, for treatment of sinusitis. Fourteen of these children presented with intracranial extension of the infection and abscess formation. A retrospective review of these patients revealed that the risk of developing an intracranial abscess secondary to sinusitis was 3%. The management of these patients included surgical drainage of the infected sinuses and intracranial surgical exploration. Cranialization and exenteration of the frontal sinus proved to be effective single-stage procedures. While not indicated in all patients, these procedures eliminated the sinus as a source of continued or potential infection and obviated the need for a second obliterative procedure. Combined antimicrobial therapy and surgical drainage should be the management protocol.

Adolescent↗
PubMed1995

Branchial anomalies: a review of 52 cases.

Fifty-two patients with branchial anomalies (BA) treated at the Children's National Medical Center between 1983 and 1993 were reviewed to determine the incidence of different types of anomalies and to analyze the authors' method of diagnosis and management. First BA was seen in 25%, second in 40%, third in 8%, and fourth in 2%. In 25%, the origin of the anomaly was undetermined. Our incidence of first BA was significantly higher than the incidence reported in other series. Of the anomalies, sinuses were more common than cysts or fistulae. Sinuses tend to present at an earlier age than cysts, which take time to enlarge and present clinically. Repeated incision and drainage and incomplete excisions were frequently seen with first, third, and fourth anomalies due to misdiagnosis. Recent trend has been to utilize radiographic studies more frequently, and they have been found to be helpful in guiding surgical therapy, particularly with the more complicated cases.

Adolescent↗
PubMed1994

A randomized double-blind trial of ondansetron alone versus in combination with dexamethasone versus in combination with dexamethasone and lorazepam in the prevention of emesis due to cisplatin-based chemotherapy.

OBJECTIVE: To compare the effectiveness and side effects of antiemetic regimens using ondansetron alone (O) versus ondansetron plus dexamethasone (OD) versus ondansetron plus dexamethasone plus lorazepam (ODA) in the prevention of emesis induced by cisplatin-based chemotherapy. DESIGN: Randomized, double-blind trial. PATIENTS AND METHODS: In this study, 75 patients who were receiving cisplatin (60 mg/m2) on day 1 and 5-fluorouracil (1,000 mg/m2) on day 2 to day 6 were enrolled. Patients were randomized to one of three treatment regimens: O, OD, or ODA. The patients assigned to O regimen received ondansetron 8 mg intravenously as a loading dose 15 minutes prior to cisplatin, then 1 mg/h continuous i.v. infusion (24 mg/day) for 48 hours. OD regimen consisted of ondansetron given as above plus dexamethasone administered at a dose of 10 mg i.v. injection every 12 hours for 3 days. ODA regimen was OD regimen plus lorazepam administered at a dose of 0.5 mg orally every 6 hours for 3 days. To ensure blinding, O group patients received 10 ml placebo-saline i.v. injection every 12 hours for 3 days, and O and OD group patients received placebo tablets orally every 6 hours for 3 days. RESULTS: One patient did not receive assigned antiemetic regimen and was excluded from the analysis. In the acute phase, complete control of emesis was seen in 85% of all patients, and there was no significant difference among the three groups (p = .442). Complete control of nausea during the acute phase was achieved in 10 patients (41.2%) treated with O regimen alone, in 23 patients (92.0%) treated with OD regimen, and in 16 patients (64.0%) treated with ODA regimen (p < .001). In the delayed phase, 68% of patients who received the three-drug combination (ODA) and 56% of patients who received the two-drug combination (OD) obtained complete control of emesis, as opposed to 29% who were given ondansetron alone (p < .021). The incidences of headache, flushing, dry mouth, hiccups, and constipation were mild and tolerable and did not differ among the three groups. DISCUSSION: Ondansetron was very effective in the prevention of nausea and vomiting during the acute phase after cisplatin administration. In treating delayed nausea and vomiting, although the results of three regimens were still disappointing, the combination of ondansetron plus dexamethasone or plus lorazepam provided superior results. Patients who received the lorazepam-containing regimen appeared more comfortable and less restless than those who were given other regimens.

Adult↗
PubMed1994

Arytenoidectomy in children.

Vocal cord paralysis is the second most common cause of stridor in early infancy, and as many as 52% of patients will not recover spontaneously. Bilateral vocal cord paralysis often requires a tracheotomy for airway distress. If resolution of the bilateral vocal cord paralysis does not allow for decannulation, arytenoidectomy is an option. A retrospective review of 30 children with bilateral vocal cord paralysis who underwent an arytenoidectomy was undertaken. An external arytenoidectomy via laryngofissure was performed in 19 patients, a laser arytenoidectomy in 12 patients, and a Woodman procedure in 1 patient. Twenty-five of the 30 patients (83%) were decannulated. Decannulation was more likely after a laryngofissure (84%) than after a laser arytenoidectomy (56%). The probability of decannulation was related to the presence of concomitant conditions and the need for other airway procedures. While breathiness, hoarseness, and pitch change were common, all patients had an adequate voice postoperatively and demonstrated little change from the preoperative voice disturbance. Aspiration was a rare complication. After an adequate period of observation for spontaneous resolution, arytenoidectomy via external laryngofissure is recommended to aid in the decannulation of children with bilateral true vocal cord paralysis.

Adolescent↗
PubMed1994

Effect of t-butylhydroperoxide on p-aminohippurat uptake in rabbit renal cortical slices.

OBJECTIVES: Oxygen free radical (superoxide radical, hydrogen peroxide, and hydroxyl radicals) have been considered to be responsible for the pathogenesis of ischemia reperfusion injury and toxic chemical injury in a variety of organs including myocardium, brain, intestine and kidneys. In in vitro models using a suspension of rat proximal tubule segments, t-butylhydroperoxide(t-BHP), a potent oxidant, induces the severity of tubular dysfunction as reflected by decreases in tubular respiration which is associated with a progressive increase in lipid peroxidation. The precise mechanism of t-BHP-induced cell injury remains to be determine. The study was carried out to determine the effect of oxygen free radicals on organic anion transport in renal proximal tubule. METHODS: By renal cortical slices, we studied accumulation of organic ions, PAH efflux oxygen consumption, lactate dehydrogenase (LDH), lipid peroxidation. The data are expressed as the mean +/- SE and evaluated for significance using Student's t-test. A probability level of 0.05 was used to establish significance. RESULTS: Effect of t-butylhydroperioxide(t-BHP), a potent oxidant, on organic anion p-amminohippurate(PAH) uptake was studied in rabbit renal cortical slices. t-BHP inhibited irreversibly PAH and organic cation tetraethylammonium(TEA) uptake in a dose dependent manner with IC50 of approximately 1.0 and 0.85 mM, respectively. The efflux rate constant pf PAH was not altered by the presence of 1 mM t-BHP, indicating that the inhibitory effect of t-BHP on the steady-state accumulation of PAH is due primary to the reduction in the influx of PAH across the basolateral membrane. The kinetic analysis showed that 1mM t-BHP caused a significant reduction in the maximum rate of PAH influx(Vmax) from 1.54 +/- 0.74 to 0.72 +/- 0.54 umol/g/10 min without an effect on Km, indicating that t-BHP depressed PAH influx across the basolateral membrane by reducing the number or turnover rate of active carrier for PAH transport, but not by altering substrate affinity of the carrier. Ouabain-sensitive and -insensitive oxygen consumption was not different between the control and t-BHP-treated slices. t-BHP caused an increase in LDH release and lipid peroxidation in a dose-dependent manner, which were highly correlated with changes in PAH uptake. CONCLUSION: These results suggest that t-BHP inhibition of PAH uptake is attributed to renal tubular cell damage and lipid peroxidation plays an important role in the inhibitory effect of t-BHP on PAH transport in rabbit proximl tubules.

Animals↗
PubMed1993

The structural basis of the inhibition of human alpha-mannosidases by azafuranose analogues of mannose.

Eight pyrrolidine, five pyrrolizidine and one indolizidine analogue(s) of the known alpha-mannosidase inhibitor, the azafuranose, 1,4-dideoxy-1,4-imino-D-mannitol (DIM), have been tested for inhibition of the multiple forms of alpha-mannosidase in human liver in vitro. Substitution of the ring nitrogen markedly decreased or abolished inhibition, but loss of the C-6 hydroxy group, as in 6-deoxy-DIM and 6-deoxy-6-fluoro-DIM, enhanced inhibition, particularly of the lysosomal alpha-mannosidase. Addition of the anomeric substituent-CH2OH decreased inhibition. To be a potent inhibitor of the lysosomal, Golgi II and neutral alpha-mannosidases, a polyhydroxylated pyrrolidine must have the same substituents and chirality as mannofuranose at C-2, C-3, C-4 and C-5. These four chiral centres can also be part of a polyhydroxylated indolizidine, e.g. swainsonine, but not of a pyrrolizidine, e.g. cyclized DIM, ring-contracted swainsonine or 1,7-diepi-australine. DIM did not inhibit lysosomal alpha-mannosidase intracellularly, but both 6-deoxy-DIM and 6-deoxy-6-fluoro-DIM caused accumulation of partially catabolized glycans in normal human fibroblasts. Analysis of these induced storage products by h.p.l.c. showed that both compounds also inhibited Golgi alpha-mannosidase II and that 6-deoxy-6-fluoro-DIM was also a good inhibitor of the endoplasmic reticulum alpha-mannosidase and specific lysosomal alpha (1-6)-mannosidase. None of the mannofuranose analogues appeared to inhibit Golgi alpha-mannosidase I.

Cells, Cultured↗
PubMed1992

Eversion endarterectomy of the cadaver donor renal artery: a method to increase the use of elderly donor kidney allografts.

Eversion endarterectomy was used to treat severe arteriosclerosis of the renal artery in 34 cadaver kidneys from elderly donors that have been considered unsuitable by other transplant centers. All kidneys were transplanted after biopsy confirmed normal histology. Graft survival and mean serum creatinine level at 4 years were 76.4% and 2.3 mg./dl., respectively. Use of these kidneys increased the number of cadaver kidney transplants at our center by 18%.

Adult↗
PubMed1992

Cyclosporin increases granulocyte/macrophage colony-stimulating factor (GM-CSF) activity and gene expression in murine keratinocytes.

Keratinocytes produce multiple cytokines in response to a variety of stimuli. The release of interleukin 1 (IL-1) from keratinocytes may be significant in initiation of cutaneous inflammation, and the presence of granulocyte/macrophage colony-stimulating factor (GM-CSF) is thought to be important in the regulation of antigen-presenting function by epidermal Langerhans cells. Because cyclosporin inhibits interleukin 2 release from T cells, it has been suggested that cyclosporin may function as an anti-inflammatory agent within the epidermis through inhibition of keratinocyte cytokine release. This investigation examined the direct effect of cyclosporin on the production of GM-CSF by murine keratinocytes and the keratinocyte cell line PAM 212. GM-CSF bioactivity increased in cell supernatants from keratinocytes exposed in vitro to 1 microgram/ml cyclosporin for up to 24 h. GM-CSF and IL-1 mRNA levels in keratinocytes cultured under similar conditions or in the presence of lipopolysaccharide also increased. The lack of inhibition of GM-CSF expression following cyclosporin treatment is consistent with recent observations in T cells and is opposite to the effect of cyclosporin on interleukin 2.

Animals↗
PubMed1990

Different outcomes of chronic hepatitis delta virus infection in woodchucks.

Hepatitis delta virus (HDV) superinfection of woodchuck chronic carriers of woodchuck hepatitis virus (WHV) results in acute and chronic disease. The different courses of disease mimicked the outcome of human HDV superinfection, making woodchucks valuable models for clinical studies of HDV. Ten of 11 woodchuck chronic carriers of WHV superinfected with HDV developed acute HDV infection with markers of viral replication in the serum and liver. One animal (DW128) had no serological markers of acute HDV infection. Nine of 11 (82%) superinfected animals developed chronic HDV infection. An unusual course of chronic HDV infection occurred in one woodchuck (DW128): no serum markers of acute or chronic HDV infection appeared but HDV RNA was detected in the liver, indicating that chronic HDV infection can occur without serological markers.

Acute Disease↗
PubMed1989

Inhibition of hepatitis delta virus RNA replication in primary woodchuck hepatocytes.

Cell cultures of primary woodchuck hepatocytes can be infected with hepatitis delta virus (HDV) as demonstrated by the appearance of genomic HDV RNA 7 days after inoculation. This tissue culture system was used to study the effect of antiviral substances. Ribavirin inhibited HDV replication at a concentration of 10 micrograms/ml, if added up to three days post infection. Suramin had an inhibitory effect only when added simultaneously with the virus, at a concentration of 200 micrograms/ml. This concentration had no toxic effect on primary woodchuck hepatocytes. alpha-Amanitin showed a weak inhibitory effect only at the highest nontoxic concentration of 0.1 microgram/ml. Acyclovir had no effect.

Amanitins↗
PubMed1989

Surgical management of voice disorders.

Voice disorders are frequently seen in the pediatric population. They can have significant impact on the patient. Voice disorders may result from aberrations in the speech mechanism. The salient features of four common voice disorders and their clinical relevance are discussed.

Child↗
PubMed1988

Propagation of woodchuck hepatitis delta virus in primary woodchuck hepatocytes.

Monolayer cell cultures of primary woodchuck hepatocytes, prepared by perfusing the liver in situ with collagenase type I, yielded hepatocytes with a viability of greater than 90% which could be held in culture for up to 3 months. Cultures of primary woodchuck hepatocytes were infected one day after plating with hepatitis delta virus (HDV) which had been passaged five times in woodchucks and was therefore identified as woodchuck hepatitis delta virus (WHDV). Replication of WHDV was demonstrated by the appearance of genomic WHDV RNA of ca. 1.7 kb beginning 7 days after infection, with an increase of copy numbers up to 2 weeks after inoculation. Synthesis of hepatitis delta virus-associated antigen (HDAg) in hepatocytes was detected by immunofluorescence staining of hepatocytes. Preincubation of the inoculum with rabbit sera containing antibodies against woodchuck hepatitis virus surface antigen (anti-WHs) reduced the infectivity of WHDV to an undetectable level compared with inocula which were treated with anti-WHs negative sera.

Animals↗