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Biomedical subjects

N K Lee

Publications and source records attributed to N K Lee.

At least 19 recordsLinked to original sources
PubMed2001

The excisional, plication and internal drainage techniques: a comparison of the results for idiopathic hydrocele.

OBJECTIVE: To assess the results of the excision, plication and internal drainage techniques for hydrocele repair. PATIENTS AND METHODS: Between January 1990 and June 1998, 132 patients (mean age 54.36 years, range 16-83) underwent repair for idiopathic hydrocele using one of three techniques (excision, eversion/plication or internal drainage); the complication and recurrence rates of each technique were evaluated. RESULTS: The excisional technique resulted in the highest complication rate (81%) and the internal drainage technique the lowest (7%). Postoperative scrotal oedema occurred in 74% of patients after plication and this was the highest rate among the techniques (P < 0.001). Differences in the rates of wound infection and haematoma among the three techniques were not statistically significant. The internal drainage technique had the highest recurrence rate (85%) and the excisional technique the lowest (1.3%; P < 0.001). CONCLUSIONS: Although useful, the internal drainage technique has a high recurrence rate and we suggest abandoning its use for hydrocele repair. The present results suggest that plication is better than excision, causing fewer complications, and better than internal drainage, as the results are more favourable.

Adolescent↗
PubMed2000

Evidence for basolateral but not apical membrane localization of outwardly rectifying depolarization-induced Cl(-) channel in airway epithelia.

The rat primary cultured-airway monolayer had been an excellent model for deciphering the ion channel after nystatin permeabilization of its basolateral or apical membrane (Hwang et al., 1996). After apical membrane permeabilization of rat primary cultured-airway monolayer, 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS)-sensitive outwardly rectifying depolarization-induced Cl(-) (BORDIC) currents were observed across the basolateral membrane in symmetrical NMG-Cl solution in this study. No significant Cl(-) current induced by the application of voltage clamping was observed across the apical membrane in symmetrical NMG-Cl solution after basolateral membrane permeabilization. The halide permeability sequence for BORDIC current was Br(-) = I(-) > Cl(-). BORDIC current was not affected by basolaterally applied bumetanide (0.5 mm). Basolateral DIDS (0.2 mm) but not apical DIDS inhibited CFTR mediated short-circuit current (I(sc)) in an intact monolayer of rat airway epithelia, a T84 human colonal epithelial cell line, and a Calu-3 human airway epithelial cell line. This is the first report showing that depolarization induced Cl(-) current is present on the basolateral membrane of airway epithelia.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2000

Two cases of perineal ectopic testis.

PURPOSE: Perineal ectopic testis is seen very rarely and here we report on two patients with perineal ectopic testis. METHODS/RESULTS: We experienced two cases of perineal ectopic testis on which orchiopexies to the corresponding hemiscrotums were performed. CONCLUSIONS: On surgical exploration, the gubernaculum testes were found to lie fixed to the perineum.

Adult↗
PubMed2000

Infected hydrocele in a neonate.

A case of infected hydrocele in a neonate is presented. We describe this unusual condition, and discuss the diagnosis, pathophysiology and treatment.

Anti-Bacterial Agents↗
PubMed1999

The preventive effect of systemic treatment with interferon-alpha2B for infertility from mumps orchitis.

OBJECTIVE: To evaluate the effect of interferon-alpha2B on mumps orchitis, often caused by postpubertal mumps and which can result in permanent testicular atrophy. PATIENTS AND METHODS: The study included 21 patients with mumps orchitis, treated between May 1990 and June 1997. Patients were randomly assigned into two groups: in group 1, 13 patients received therapy with interferon-alpha2B (3 x 10(6) IU per day) and group 2 did not, acting as controls. All were evaluated by measurements of testis size, mumps virus titre, hormone level and semen analysis. RESULTS: In group 1, the patients' symptoms resolved within 2-3 days and the volume of the testes returned to normal within 11 days; there was no testicular atrophy in any patient during the follow-up. However, asthenospermia continued to be detected in four patients (unilateral in two, bilateral in two). In group 2, the patients' symptoms resolved within 5-6 days and the volume of the testes returned to normal within 10 days; testes atrophied in three patients (unilateral in two, bilateral in one) during the follow-up. Asthenospermia continued in four patients (unilateral in two, bilateral in two). CONCLUSION: These results suggest that treatment with systemic interferon-alpha2B is effective in preventing testicular atrophy when combined with standard symptomatic treatment.

Adolescent↗
PubMed1998

The differential role of alcohol expectancies and drinking refusal self-efficacy in problem and nonproblem drinkers.

OBJECTIVE: The present study aimed to examine the discriminatory ability of alcohol expectancies and drinking refusal self-efficacy and to identify the differential role of these constructs in social and problem drinkers. METHOD: Drinkers (N = 276) were self-selected from general (n = 185) and clinical (n = 91) populations to complete a 40-minute questionnaire that asked about alcohol expectancies, drinking refusal self-efficacy, consumption, degree of dependence and demographics. RESULTS: The results showed that in social drinkers both the expectancy and self-efficacy constructs were reliably able to discriminate between types of drinker. Expectancy was related to consumption in social drinkers, but did not appear to account for a significant proportion of the variance in problem drinkers. CONCLUSIONS: The findings are discussed in terms of a two-process model of drinking behavior that suggests that expectancies operate differently in social and problem drinkers.

Adult↗
PubMed1997

Alternatamides A-D: new bromotryptamine peptide antibiotics from the Atlantic marine bryozoan Amathia alternata.

Four new bromotryptamine peptides, alternatamides A-D (1-4), have been isolated from the Atlantic bryozoan Amathia alternata. The structures of the alternatamides were assigned primarily on the basis of 2D NMR data. The absolute stereochemistry of the N-methylleucine amino acid was shown to be L (2'S) by hydrolysis and comparison with standards. The alternatamides show modest antibacterial activities against several Gram-positive bacteria.

Animals↗
PubMed1996

Frequent allelic loss at chromosome arm 3p is distinct from genetic alterations of the Von-Hippel Lindau tumor suppressor gene in head and neck cancer.

Previous molecular genetic studies revealed that allelic loss of chromosome arm 3p is a frequent event in upper aerodigestive tract squamous cell carcinoma (UADT SCC). Recently, the Von-Hippel Lindau (VHL) tumor suppressor gene was identified at chromosome band 3p25-26. To determine if the VHL locus is altered in these tumors, a paired series of 26 tumors and blood from patients with UADT SCC that were previously shown to exhibit allelic loss of 3p were tested for LOH surrounding the VHL locus using four different polymorphic markers. All of the samples (100%) exhibited LOH for at least 1 marker. However, no LOH was detected using a polymorphism within exon 1 of the VHL gene which was informative for 18 of the 26 cases. Furthermore, mutations of the VHL gene could not be identified by single-strand conformation polymorphism, dideoxyfingerprint or direct DNA sequence analysis. In addition, the VHL gene was not inactivated by hypermethylation in any of the 26 tumor samples studied. These findings demonstrate that allelic loss of chromosome arm 3p in UADT SCC involves regions surrounding the VHL locus but does not include the VHL gene. The VHL gene, therefore, does not appear to be involved in the pathogenesis of UADT SCC.

Carcinoma, Squamous Cell↗
PubMed1994

Allelic loss at chromosomes 3p, 8p, 13q, and 17p associated with poor prognosis in head and neck cancer.

BACKGROUND: Little is known about the molecular genetic events that contribute to the pathogenesis of squamous cell carcinoma of the upper aerodigestive tract. Previous molecular genetic studies have been limited to the identification of mutations of the p53 (also known as TP53) tumor suppressor gene, activation of a limited set of oncogenes, allelic loss at 3p and other locations, and occasional association with human papillomavirus infection. PURPOSE: Our purpose was to screen tumor tissue and blood from patients with squamous cell carcinoma of the upper aerodigestive tract for loss of heterozygosity at polymorphic loci corresponding to each of the autosomal chromosomes and to identify the locations of additional putative tumor suppressor genes, other than RB (also known as RB1) and p53, that may contribute to the pathogenesis of this disease. METHODS: Tumor tissue and blood were obtained from 68 consecutive patients with squamous cell carcinoma of the upper aerodigestive tract. In all cases, tumor tissue was obtained from the center of the surgical specimen. The relative absence of non-neoplastic tissue was confirmed by frozen-section histologic examination of immediately adjacent tissue. Initially, 30 paired tissue and blood samples were tested for loss of heterozygosity by polymerase chain reaction (PCR) to amplify 43 different highly polymorphic sequences containing small oligonucleotide repeats. After PCR amplification, with unique oligonucleotides flanking the repeat, visualization and sizing of the alleles on DNA sequencing gels were performed. Specific loss of heterozygosity was distinguished from random genetic loss due to generalized chromosomal instability if it occurred in more than 20% of specimens tested for a particular marker. RESULTS: Significant loss of heterozygosity (> 20%) occurred at alleles at chromosome bands 3p21 (32%), 3p25-26 (56%), 8pter-21.1 (31%), 13q14 (27%), and 17p12 (45%). Loss of heterozygosity at more than two loci was significant with a poor prognosis (P = .039). CONCLUSIONS: These findings demonstrate that squamous cell carcinoma of the upper aerodigestive tract exhibits genetic alterations at multiple loci and that allelic loss at more than two locations is indicative of a poor prognosis (the likelihood of the patient dying of disease). IMPLICATIONS: While tumor suppressor genes at 3p (VHL), 13q (RB), and 17p (p53) have been identified, altered genes at other loci on 3p and on 8p have not yet been characterized. Furthermore, the genotype at these loci for squamous cell carcinoma of the upper aerodigestive tract has prognostic importance and may identify the patients who should receive the most aggressive treatment.

Adult↗
PubMed1994

Endoscopic resection of the intranasal frontal sinus floor.

The current accepted treatment for chronic frontal sinus disease unresponsive to medical management and endoscopic surgery is an external approach to either obliterate the sinus or restore communication to the nasal cavity. Here reported is an endoscopic approach for resection of the intranasal frontal sinus floor, a modification of a procedure first described by Lothrop in 1899. Eleven patients underwent this operation from April 1993 to December 1993. One complication, a cerebrospinal fluid leak treated successfully endoscopically, has occurred. Of the 7 patients followed up 3 months or longer after surgery, only 1 has developed symptoms of recurrent frontal sinusitis. On the basis of this limited preliminary experience, the endoscopic Lothrop procedure shows promise as an effective operation designed to establish a physiologic communication between the frontal sinus and the nasal cavity in selected patients who would otherwise be candidates for an external approach.

Adolescent↗
PubMed1993

p53, retinoblastoma, and human papillomavirus in squamous cell carcinoma and adjacent normal mucosa of the upper aerodigestive tract.

OBJECTIVE: The primary objective of this study was to determine the incidence of p53 and retinoblastoma tumor suppressor gene mutations and human papillomavirus infection in squamous cell carcinoma and adjacent normal mucosa of the upper aerodigestive tract. The secondary objective was to associate these findings with clinical and histopathologic features. DESIGN: Point mutations of p53 were identified by single-strand conformation polymorphism analysis and confirmed by direct DNA sequence analysis. Polymerase chain reaction-based methods were used to identify loss of heterozygosity of the retinoblastoma tumor suppressor gene and the presence of human papillomavirus sequences. SETTING: University-based tertiary care center. PATIENTS OR OTHER PARTICIPANTS: Forty-five consecutive cases of upper aerodigestive tract squamous cell carcinoma. RESULTS: Eleven point mutations of p53 were identified in tumor samples (24%). No functional p53 mutations were detected in adjacent normal tissue from eight of these individuals nor was there evidence of p53 alteration in normal tissue adjacent to 12 of 30 additional tumors tested that demonstrated conformational alterations by single-strand conformation polymorphism analysis. The p53 mutations were significantly associated with local invasion. Loss of heterozygosity (which has a 20% chance of random occurrence in tumors) was detected at the retinoblastoma locus in 15% of the tumors tested. Five of the specimens (11%) were positive for human papillomavirus sequences (two of which also contained p53 mutations). CONCLUSIONS: These findings suggest that p53 but not retinoblastoma or human papillomavirus is an important prognostic factor and is involved as a late event in the pathogenesis of upper aerodigestive tract squamous cell carcinoma.

Base Sequence↗
PubMed1993

The importance of alcohol expectancies and drinking refusal self-efficacy in the quantity and frequency of alcohol consumption.

Expectancies about alcohol have been shown to be related to and predictive of alcohol consumption. Research to date, however, has often failed to make a clear distinction between expectations about the effects of alcohol (alcohol expectancies) and expectations about one's ability to resist drinking in certain situations (drinking refusal self-efficacy). There is some evidence that alcohol expectancies (AE) and drinking refusal self-efficacy (DRSE) can play differential roles in the prediction of consumption in terms of quantity and frequency of drinking. This study aimed to replicate and extend these findings to the community population. Subjects (N = 185) were recruited from the general community using a peer network system. They were given a booklet comprising six self-report measures, including the Drinking Expectancy Questionnaire (DEQ), the Drinking Self-Efficacy Questionnaire (DSEQ), and the Khavari Alcohol Test (KAT), which produces measures of usual and maximum quantity as well as frequency of the usual and maximum consumed. It was expected that AE would be related to frequency of consumption whereas DRSE would be related to both quantity and frequency. The findings confirmed the differential role of AE and DRSE in drinking, and the role of factors within the two concepts. Results indicated that low DRSE was related to higher frequency of general consumption and a larger maximum quantity on any one occasion. AE was related to frequency, but not to quantity, as expected. The findings are presented with respect to the theoretical constructs; clinical and research implications are also discussed.

Adolescent↗
PubMed1993

Splenic and partial hepatic necrosis after vascular occlusion.

A 74-year-old woman underwent two operations to correct an aortoduodenal fistula and to have an axillofemoral bypass graft inserted; these required temporary vascular occlusion. Her hepatic function test results began deteriorating. Initial and follow-up Tc-99m sulfur colloid studies revealed activity in the kidneys, consistent with disseminated intravascular coagulation. There was significant radiocolloid in the bone marrow and lungs, suggesting severe hepatic dysfunction. The spleen was not demonstrable on dynamic images or static views. In addition, there was a significant lateral hepatic defect, with a "lung overlap." The splenic lack of function and the hepatic lesion were due to necrosis (demonstrable on CT imaging), likely related to the prior vascular clamping.

Abdomen↗
PubMed1992

Inositol trisphosphate (InsP3) causes contraction in skeletal muscle only under artificial conditions: evidence that Ca2+ release can result from depolarization of T-tubules.

It has been proposed that in striated muscle inositol 1,4,5-trisphosphate (InsP3) may serve as a chemical transmitter linking membrane depolarization to Ca(2+)-release from the sarcoplasmic reticulum. Key to that hypothesis of excitation-concentration (EC) coupling was the observation that skinned muscle fibres contract on the application of InsP3. Yet skinned fibres do not always respond in this way, and in our hands intact fibres do not contract when InsP3 (1 microM-1 mM) is microinjected into them. Glycerol-shocked fibres do contract, however, and so do intact fibres that have been depolarized to about -50 mV by increasing [K+]0. These observations and related pharmacological evidence support the hypothesis that InsP3 causes a low-level depolarizing current to cross the T-tubular membrane. This current is sufficient to depolarize the T-tubules to the threshold for contraction only when the tubules are sealed over or when they are already close to the threshold. The InsP3-induced Ca2+ release sometimes observed in skinned muscle fibres and in vesicles derived from junctional sarcoplasmic reticulum probably often results from an action on sealed-over transverse tubules; in such situations it is an artifact of cell disruption. The fact that high concentrations of InsP3 do not cause contraction in normal muscle fibres is strong evidence against the hypothesis that InsP3 plays a central role in EC coupling in skeletal muscle.

Aequorin↗
PubMed1992

Ventilation-perfusion lung imaging in nitrofurantoin-related pulmonary reaction.

A woman with a history of multiple drug allergies was admitted for cough and dyspnea. She had been taking nitrofurantoin for 10 days, was febrile, and had a rash on the trunk and extremities. A chest radiograph revealed right-sided pleural effusion and basal markings. Because of suspected nitrofurantoin-related pulmonary reaction, the medication was discontinued and the patient was started on an H2-blocker and intravenous corticosteroids. She improved clinically, and within 24 hours a radiograph revealed that her chest had largely cleared. Restricted distribution of radioxenon, seen initially on a ventilation lung scan, also reverted to near normal by the follow-up. The first perfusion lung scan showed multiple but nonspecific changes; this also came back to near normal. The nitrofurantoin-related pulmonary reaction should be considered in patients who present with pulmonary signs/symptoms while on the medication.

Drug Hypersensitivity↗
PubMed1991

Metastatic adenocarcinoma to the neck from an unknown primary source.

We report a retrospective review of 223 patients who presented to the Department of Head and Neck Surgery from 1970 through 1987 with a diagnosis of metastatic adenocarcinoma of unknown primary origin. Multivariate analysis was performed using the following parameters: age, sex, initial side and site of nodal involvement, involvement of other body sites, degree of differentiation, treatment modality, outcome, and survival. Follow-up was obtained in all patients, with a minimum of 2 years for survivors. Average age was 55 years, with an approximately equal male:female ratio. The most common site of presentation was the supraclavicular fossa (76%). The initial side of presentation was the left neck in 53% of patients, right neck in 33%, and bilateral in 14%. Metastatic disease to other body sites was present in 86% of patients, with the most common sites being mediastinum (35%), lung (21%), and bones (19%). Increased survival was associated with unilateral neck involvement (p = 0.001) and disease limited to nodes above the cricoid cartilage (p = 0.007). Mean survival was 17 months, with a median of 8 months. Death was due to the index cancer in all but four patients; three of these four patients died of treatment-related causes. Survival was 20% at 2 years and 9% at 5 years. Length of survival was not affected by age, sex, initial side of neck disease, location of other metastatic sites, histologic appearance, or treatment modality. Our current algorithm for the work-up and treatment of this lethal disease is explained.

Adenocarcinoma↗