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Biomedical subjects

H L Lee

Publications and source records attributed to H L Lee.

At least 73 records · Page 4Linked to original sources
PubMed2000

Predictive efficacy of motion sickness history for airsickness.

BACKGROUND: Airsickness is a common problem in the early stage of flying training. It can be sufficiently severe to impair the student's flight performance and his ability to learn. Without adequate evaluation and rehabilitation, intractable airsickness symptoms will force student pilots to be permanently grounded. The purpose of this study was to evaluate the predictive efficacy of motion sickness history for airsickness of flight students. METHODS: A motion sickness history questionnaire with four different scores was used to predict airsickness of student pilots in the Air Force Academy. The questionnaire asked subjects questions about the severity and frequency of motion sickness symptom experienced in nine different motion sickness situations before and after 12 years of age. The results were grouped to four different scores. Pearson correlation and Student's t-test methods were used to evaluate the correlations of the four different scores. RESULTS: A total of 76 flight students in the class of 1997 who had under gone their flight-training course were included in this study. They were all healthy males with a mean age of 22.2 years (range, 20-24 years). The airsickness incidence of student pilots was 50%. The four different scores of motion sickness history questionnaire were highly correlated (r = 0.69-0.86, p < 0.01). The "after 12 years-of-age actually sick" score key had greater predictive validity for airsickness than the other motion sickness history questionnaire score keys and so did the "before 12 years-of-age feels sick" and "after 12 years-of-age feels sick" for no airsickness. CONCLUSIONS: The motion sickness history questionnaire was an efficient method to predict airsickness among Air Force student pilots.

Adult↗
PubMed1999

The molecular basis for the B(A) allele: an amino acid alteration in the human histoblood group B alpha-(1,3)-galactosyltransferase increases its intrinsic alpha-(1,3)-N-acetylgalactosaminyltransferase activity.

The formation of the subgroup B(A) phenotype is thought to be due to an overlapping specificity of the human blood group A and B transferases. A new molecular basis for the B(A) allele, resulting from the C(700) to G substitution which predicts the alteration of Pro(234) to Ala, just ahead of the second of the four amino acid residues which differentiates the specificities of the A and B transferases, is reported here. Compared to normal group B sera, a relatively lower B-transferase activity was demonstrated in the B(A) serum, which correlated well with the observation of a smaller amount of B antigen on the B(A) red cells. Also a much higher A-transferase activity was demonstrated in the B(A) serum in contrast to the minute amount of A-transferase activity found in normal group B sera. The formation of the B(A) phenotype in this report is most likely due to the shifting of the specificity of the B transferase rather than an enhanced B-transferase activity which was previously presumed to be responsible for the formation of this phenotype. The Pro(234) to Ala alteration is suggested to be responsible for the shifting of the specificity with a subsequent increase in A- but a decrease in B-transferase activity. This new B(A) allele shows that not only the four critical residues but also the neighboring areas may influence the specificity of the A and B transferases.

ABO Blood-Group System↗
PubMed1999

Acute poisoning with a herbicide containing imazapyr (Arsenal): a report of six cases.

BACKGROUND: Acute pesticide poisoning is a major cause of morbidity and mortality in Taiwan and herbicides are most frequently implicated. Imazapyr [2-(4-isopropyl-4-methyl-5-oxo-2 imidazoline-2-yl)nicotinic acid] is a new herbicide, recently registered in Taiwan under the tradename "Arsenal" (Imazapyr 23.1%, Cyanamid Taiwan Corporation, Taipei). Imazapyr is also marketed as Assault, Chopper, Contain, and Pivot. To the best of our knowledge, there is no information in the literature concerning acute toxicity in humans after ingestion of herbicides containing this compound. METHOD: Six cases of acute poisoning with Arsenal occurred during the period 1993-1997 in a single hospital. Emergency room records and medical charts were reviewed. RESULTS: Of 6 cases, 5 were suicide attempts and 1 was an act of violence inflicted on a child. Three of the 6 patients (50%) presented with severe symptoms, including impairment of consciousness and respiratory distress requiring intubation. Other presentations included metabolic acidosis (2), hypotension (2), leukocytosis (3), fever (2), mild elevation of hepatic transaminase and creatinine (2), unconjugated hyperbilirubinemia (2), oral ulceration (2), pharyngolaryngitis (2), and chemical burns of the cornea (1). All cases had copious vomiting after ingestion of Arsenal. No mortality occurred. CONCLUSION: According to our observations, it appeared the toxic syndrome that results from a large quantity (> 100 mL) of Arsenal herbicide ingestion consists of hypotension, pulmonary dysfunction, oral mucosal and gastrointestinal irritation, and transient liver and renal dysfunction. However, the existence of a dose-response relationship, with increasing amounts of ingestion resulting in more severe symptoms, needs further observation and studies that include a larger series.

Adult↗
PubMed1999

A newly identified nonsecretor allele of the human histo-blood group alpha(1,2)fucosyltransferase gene (FUT2).

BACKGROUND AND OBJECTIVES: The human Secretor alpha(1, 2)fucosyltransferase gene determines the ABH secretor status and influences the Lewis phenotype of an individual. Studies were carried out on the Lewis (a+b-) nonsecretors of different groups indigenous to Taiwan to demonstrate their se genotypes. METHODS: The Lewis phenotype of the blood samples was determined by a microplate method. The se genotypes of the individuals with the Lewis (a+b-) phenotype were analyzed by a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method designed for the se alleles reported previously. PCR and cloning techniques were used to determine the coding sequence of the novel se gene. RESULTS: A new se allele, se685, with a three-nucleotide deletion of GTGGT to GT in the coding region of nucleotides 685 through 689 was identified in a Le (a+b-) nonsecretor from the Ami tribe indigenous to Taiwan. The deletion predicts the loss of the amino acid Val230 in the corresponding secretor enzyme's C-terminal segment. The distribution of the se685 allele in the Ami tribe was further verified by PCR-RFLP analysis. CONCLUSION: The Se gene exhibits heterogeneity with some Se alleles being common but others displaying a unique distribution in different ethnic populations. The newly identified se685 allele seems to exist only in the Ami tribe indigenous to Taiwan.

ABO Blood-Group System↗
PubMed1999

Susceptibility of Musca domestica L. (Diptera: Muscidae) from various breeding sites to commonly used insecticides.

Field strains of house flies, Musca domestica L., from three different breeding sites-garbage dump (IMR), poultry farm (Kundang, Selangor), and agricultural farm (Kampung Batu, Kuala Lumpur), were evaluated against five insecticides. Resistance status of adult female flies was determined using the modified WHO bioassay methods. The WHO susceptibility strain was used as a reference strain for comparison. Flies from the garbage dump and poultry farm were more resistant to the insecticides than the strain from the agricultural farm. Results obtained from bioassay tests were confirmed by in-vitro microenzyme assays of non-specific esterases and glutathione-S-transferases. Significant differences between the esterase levels of WHO and field strains were observed. Levels of glutathion-S-transferases were approximately the same, which may indicate that other enzymes are involved in house fly resistance.

Animals↗
PubMed1999

Fatal hyperkalemia during rapid and massive blood transfusion in a child undergoing hip surgery--a case report.

We report a girl who developed severe and fatal hyperkalemia following rapid and massive blood transfusion during surgery. She was 7-year-old, 20-kg in weight, and received wide resection of the femoral bone with custom prosthesis implant because of malignant femoral osteosarcoma. During the procedure, bleeding was active and profuse and amounted to about 3,000 mL in 4 h, eventuating in shock. Despite rapid transfusion with 15 units of packed red blood cells (RBC) still she remained hypotensive and hypovolemic. When we switched to give her whole blood, actually 100 mL having been given, widening of QRS complex followed immediately by cardiac arrest developed. Cardiopulmonary resuscitation although started at once was unsuccessful. At this juncture, arterial blood gas analysis showed acidosis and severe hyperkalemia (10.3 mmol/L), possibly resulting from transfusion of blood of older storage. The case reminded us once again the importance and necessity of the use of potassium-low blood component (fresh, saline-washed RBCs) in case of massive and rapid blood transfusion especially in pediatric patients with hypovolemia and low cardiac output.

Bone Neoplasms↗
PubMed1999

Compatibility of Bacillus thuringiensis serovar israelensis and chemical insecticides for the control of Aedes mosquitoes.

The compatibility of the commercial aqueous Bacillus thuringiensis serovar israelensis (B.t.i.) formulation, Vectobac 12AS, with the chemical insecticides Actellic 50EC, Aqua Resigen, Resigen, and Fendona SC, for the simultaneous control of Aedes larvae and adults was studied by dispersing nine different formulations using a portable mist blower, in single story half-brick houses. The effectiveness of the treatment was evaluated by measuring the larval mortality, adult mortality, and droplet analysis at varying distances from the sprayer. Persistence of the larvicidal activity of the chemical insecticides and B.t.i was also determined by measuring the larval mortality in the test samples 7 days posttreatment. The sprayed particles in all the trials were 50-60 microns in size, indicating that the particles were those of mist spray. Test samples placed within 3 m from the sprayer gave the maximum larval and adult mortality. Chemical insecticides exhibited maximum larval mortality in the 1 h posttreatment test samples and it was comparable to the larvicidal activity of B.t.i. The larvicidal toxins of B.t.i were more stable and were able to affect sufficient larval mortality for 7 days posttreatment. The larvicidal activity of the mixtures, i.e., chemical insecticides with B.t.i, in the 1 h posttreatment test samples was not significantly different from the larvicidal activity of the chemical insecticides and it was comparable to the larvicidal activity of B.t.i alone. However, the larvicidal activity of the mixtures was significantly more than the chemical insecticides alone in the 7 days posttreatment test samples except for the Actellic 50EC and Vectobac 12AS mixture. In all the trials, with or without B.t.i, there was no significant difference in adult mortality, indicating that this B.t.i formulation, Vectobac 12AS, was not antagonistic to the adulticidal activity of the chemical insecticides. From this study, it can be concluded that chemical insecticides can be used effectively for both adult and larval control, but the chemical insecticides do not exhibit residual larvicidal activity. Hence, for an effective control of both Aedes larvae and adults, it is advisable to add B.t.i. to the chemical insecticides, as B.t.i is specifically larvicidal and is also able to effect extended residual larvicidal activity.

Aedes↗
PubMed1998

Prolonged glucocorticoid exposure dephosphorylates histone H1 and inactivates the MMTV promoter.

Glucocorticoids rapidly induce transcription from the mouse mammary tumour virus (MMTV) promoter via a glucocorticoid receptor (GR)-mediated chromatin disruption event. This remodelling of chromatin is transient such that upon prolonged exposure to hormone the promoter becomes refractory to glucocorticoids. We demonstrate that this refractory state requires the continual presence of hormone and can be reversed by its removal. Our experiments show that the promoter is inactivated via a mechanism whereby histone H1 is dephosphorylated in response to glucocorticoids. Removal of glucocorticoids results in the rephosphorylation of histone H1 and the reacquisition of transcriptional competence by the promoter. This response is specific for the MMTV promoter assembled as chromatin and is not observed for another inducible gene or transiently transfected MMTV DNA. Finally, we demonstrate that H1 on the MMTV promoter is dephosphorylated when the promoter is unresponsive to glucocorticoids. These studies indicate that phosphorylated H1 is intimately linked with the GR-mediated disruption of MMTV chromatin in vivo.

Animals↗
PubMed1998

Simultaneous determination of seven sulfonamide residues in swine wastewater by high-performance liquid chromatography.

A HPLC-UV method was used for simultaneous determination of the residual sulfonamides in swine wastewater. Sulfonamides were extracted with ethyl acetate prior to chromatographic analysis. An ODS column was used for separation and UV detection was used to monitor the sulfonamides. Factors that affect the chromatographic behavior and the recovery have been studied. Calibration graphs were linear with very good correlation coefficients (r > 0.9999) from 0.05 to 10 micrograms/ml. The applicability of the method to the analysis of swine wastewater samples was demonstrated.

Animals↗
PubMed1998

Fasting plasma glucose in screening for diabetes in the Taiwanese population.

OBJECTIVE: To reveal the relationship between fasting and 2-h postload plasma glucose and to examine the appropriate fasting glucose cutoff as the primary screening test for diabetes. RESEARCH DESIGN AND METHODS: We recruited 5,303 subjects from preventive services of the National Cheng Kung University Hospital. Exclusion criteria were age <20 years, pregnancy, known diabetes, and a history of recent surgery, trauma, or illness. All subjects received the 75-g oral glucose tolerance test. The relationship between fasting and 2-h glucose was examined. Sensitivities, specificities, efficiency, and predictive values were assessed at different cutoffs of fasting glucose for prediction of diabetes. RESULTS: The best fit model for the relationship between fasting and 2-h glucose was fasting glucose = 4.914-0.060 x (2-h glucose) + 0.0144 x (2-h glucose)2. From this model, the fasting glucose was 6.0 mmol/l when 2-h glucose was 11.1 mmol/l. A fasting glucose with 6.25 mmol/l gave the same diabetes prevalence as the World Health Organization 2-h glucose criterion. When 7.8 mmol/l was the fasting glucose cutoff, the sensitivity was 28.5%. Lowering the cutoff from 7.8 to 7.0 mmol/l increased the sensitivity by 11.2% and slightly reduced the specificity and positive predictive value. If the cutoffs were 6.25 and 6.0 mmol/l, the sensitivity increased and the specificity and the positive predictive value decreased accordingly. CONCLUSIONS: Our results suggest that fasting glucose as a screening criterion for diabetes could be revised downward to 7.0 mmol/l, because the slight reduction of positive predictive value was more than balanced by an apparent increase of sensitivity and insignificant change of specificity.

Adult↗
PubMed1998

Rate of resistance development in wild Culex quinquefasciatus (Say) selected by malathion and permethrin.

Wild caught female Culex quinquefasciatus (Say) from Kuala Lumpur were blood fed and reared in the insectarium. The late third stage of the F1 larvae which survived the high selection pressure of malathion and permethrin were reared and colonies were established from adults that emerged. Larvae from these colonies were then subjected in the subsequent 9 generations to higher selection pressure. The rate of resistance development were measured by LC50 value of larval bioassay, LT50 value of adult bioassay and the frequency of the elevated esterase levels. In another set of experiments using the same batch of Culex mosquitos, the larvae were not exposed to any insecticides and the decrease in resistance rate was monitored in each subsequent 9 generations by using similar methods. The heterozygous standard laboratory strain was selected for susceptibility using the single raft sib-selection method. The result showed that the field collected F1 generation was 96.0 and 6.3 fold more resistant to malathion and permethrin, respectively. After selection for about 9 generations the resistance ratio to malathion and permethrin was 6.2 and 767.3 fold more compared to the LC50 values of F1 generations, respectively. Esterase in F1 larvae was 6.0 fold more than the standard laboratory strain.

Animals↗
PubMed1997

Visualization of multicomponent transcription factor complexes on chromatin and nonnucleosomal templates in vivo.

There is increasing evidence that specific chromatin structures play an important role in the regulation of transcription in eukaryotes. The mouse mammary tumor virus (MMTV) promoter, which is reproducibly assembled into a phased array of six nucleosomes when introduced into cells, represents a particularly well-studied example. The second or B nucleosome of the phased array is disrupted in response to hormone stimulation, allowing the assembly of a preinitiation complex and the activation of transcription. In vitro experiments demonstrate that the assembly of the proximal promoter into chromatin is sufficient to prevent the binding of transcription factors such as nuclear factor 1. Consequently it is argued that chromatin serves to restrict the access of ubiquitous transcription factors in the absence of hormone stimulation. We have employed an in vivo exonuclease III (ExoIII)/Taq polymerase footprinting assay to study the hormone-dependent loading of transcription factors on the MMTV promoter. This assay makes use of stable mouse and human cell lines harboring bovine papilloma virus chimeras of the MMTV promoter attached to a reporter gene. To ascertain the significance of protein-chromatin interactions vs protein-DNA interactions, we examined transcription factor binding to chromatin and nonchromatin templates of the MMTV promoter within the same cells. By the use of primers specific for each of the two distinct reporter genes, and restriction enzymes that generate entry sites for ExoIII, we can distinguish chromatin and nonnucleosomal templates in vivo. This system has allowed us to visualize the assembly of multicomponent transcription preinitiation complexes and to ascertain the consequences of defined chromatin structures on the binding of individual transcription factors in vivo.

Animals↗
PubMed1997

Mechanical transport of rotavirus by the legs and wings of Musca domestica (Diptera: Muscidae).

Factors affecting the mechanical transmission of rotavirus by the legs and wings of the housefly, Musca domestica L., were examined in a laboratory study. Rotavirus was picked up when houseflies walked on thin smears of clarified rotavirus suspensions. The addition of glycerol, which increased viscosity of the virus suspension, and particulate human feces slightly increased the proportion of flies contaminated with virus. However, the addition of glycerol greatly reduced the average number of virus particles picked up per fly, whereas feces greatly increased the number of particles. The proportion of flies with virus-contaminated legs, which transferred virus to > 1 contact surface, was increased by longer contact time with the surface and when the contact surface was agar instead of glass. Most virus particles were deposited on 1st contact with the surface. Most flies dislodged virus particles inoculated on the underside of their wings soon after the start of simulated flight. Our data indicated that the nature of the virus-suspending medium has a greater effect on the level of virus contamination than on the ability to become contaminated. The importance of walking as a mode of virus transport depends on the nature of the contact surface, the risk of the contaminated fly settling first on a surface likely to come into contact with humans, and fly numbers.

Animals↗
PubMed1997

Effects of short-term exercise on female platelet function during different phases of the menstrual cycle.

Previous studies have shown that premenopausal women have a low incidence of cardiovascular diseases, and that acute exercise affects male platelet function in an intensity-dependent manner. To investigate whether acute exercise affects female platelet function differently from males, sixteen sedentary women in the midfollicular phase or midluteal phase received strenuous or moderate exercise on a bicycle ergometer. Before and immediately after exercise, platelet adhesiveness, adenosine diphosphate-induced platelet aggregation and intracellular calcium concentration elevation, platelet cAMP and cGMP contents, urinary 11-dehydro-TXB2 and 6-keto-prostaglandin F1 alpha levels, and plasma nitric oxide metabolite level were determined. Our results showed no differences in exercise performance and in resting platelet function between two menstrual phases, with little change in urinary eicosanoid metabolites and platelet cAMP levels under all experimental conditions. In addition, for women in the midfollicular phase, (1) strenuous exercise increased platelet adhesiveness, adenosine-diphosphate-induced platelet aggregation, and intracellular calcium concentration elevation, whereas moderate exercise suppressed them; (2) moderate exercise enhanced plasma nitric oxide metabolite and platelet cGMP levels. In contrast, none of these platelet functions was affected by acute exercise in the midluteal phase. Therefore, we conclude that acute exercise affects female platelet function in an intensity-dependent manner in the midfollicular phase but not in the midluteal phase. The irresponsiveness of platelets to acute exercise in the luteal phase may partially explain why premenopausal women have a lower incidence of cardiovascular diseases than men.

Adult↗
PubMed1997

Insecticide resistance status and mechanisms in Malaysian Blattella germanica (Linnaeus).

The insecticide resistance status of 4 strains of adult male Blattella germanica, viz M (Malacca), E (England), F (restaurant) and K (cafeteria) against malathion and bendiocarb compared with a reference susceptible strain (S) was determined by using a modified WHO bioassay method. The results indicated that all the 4 strains were resistant to the insecticides albeit in different degrees. Resistance ratios for malathion ranged from 1.85-41.07-fold, whereas that of bendiocarb ranged from 1.68-4.83-fold. The biochemical microplate enzyme assays technique employed indicated that the resistance in M and E strains were attributed to acetylcholinesterase insensitivity. Multiple resistance was not detected in any of the 4 strains. Parameters of the identified resistance mechanism correlated well with the observed level of resistance. Agar gel electrophoresis showed that variations in esterase isoenzymes did not confer organophosphate and carbamate resistance to the 4 strains.

Animals↗
PubMed1997

A novel insecticidal serotype of Clostridium bifermentans.

A novel Clostridium bifermentans strain toxic to mosquito larvae on ingestion was isolated from a soil sample collected from secondary forest floor. This strain was designated as serovar paraiba (C. b. paraiba) according to its specific H antigen. Clostridium bifermentans paraiba is most toxic to Anopheles maculatus Theobald larvae (LC50 = 0.038 mg/liter), whereas toxicity to Aedes aegypti (Linn.) (LC50 = 0.74 mg/liter) and Culex quinquefasciatus Say (LC50 = 0.11 mg/liter) larvae was 20 and 3 times lower, respectively. The toxicity to An. maculatus larvae is as high as that of Bacillus thuringiensis serovar israelensis. C. b. paraiba was also found to exhibit significant per os insecticidal activity toward adult Musca domestica (Linn.).

Aedes↗
PubMed1997

Preliminary field evaluation of the combined adulticidal, larvicidal, and wall residual activity of ULV-applied bifenthrin against mosquitoes.

The combined adulticidal, larvicidal, and wall residual activity of ULV-applied bifenthrin, a synthetic pyrethroid, was evaluated in houses in Kuala Lumpur, Malaysia, against larvae and adults of lab-bred Aedes aegypti and Culex quinquefasciatus. A portable ULV sprayer was used to disperse a ULV formulation of bifenthrin at a discharge rate of 45 ml/min. The results indicated that bifenthrin sprayed at this rate exhibited all the three activities against the test mosquitoes. Complete adult mortalities were achieved, while very high larvicidal activity was also effected, which persisted for seven days. Wall bioassay with adults of Ae aegypti also resulted in very high mortality, which also persisted for one week. The combined mosquitocidal activities of bifenthrin is considered more effective especially in the control of dengue vectors.

Aedes↗