Biomedical subjects

K S Liu

Publications and source records attributed to K S Liu.

At least 19 recordsLinked to original sources

PubMed2002

Physiognomy and teeth: an ethnographic study among young and middle-aged Hong Kong adults.

OBJECTIVES: To determine knowledge and beliefs about traditional physiognomy (judging an individual's character from their facial appearance) concerning teeth among young (17-26) and middle-aged (35-44) Hong Kong adults. METHODS: In a cross sectional ethnographical telephone survey, 400 adults were interviewed about 16 traditional physiognomy concerning teeth (in consultation with a Feng Shui specialist). RESULTS: Most completed the interview (93%, 373). Over half the study group (63%, 234) claimed they had heard of aspects of physiognomy concerning teeth, and a quarter (24%, 88) believed in such ideologies. Variations in knowledge and beliefs were apparent among people of different age (P < 0.01), gender (P < 0.05), educational attainment (P < 0.01), economic status (P < 0.01), place of birth (P < 0.01) and religion (P < 0.01). Their knowledge and belief in aspects of physiognomy concerning teeth was also associated with reported use of dental services (P < 0.01). CONCLUSION: Among young and middle-aged adults in Hong Kong, knowledge and beliefs concerning traditional physiognomy regarding teeth is strong, and socio-demographic variations exist in these perceptions. These findings have implications for all those involved in the delivery of dental care in multicultural societies and in raising cultural awareness about traditional health beliefs.

Adolescent↗

PubMed2001

A survey of environmental tobacco smoke controls in California office buildings.

A survey of environmental tobacco smoke (ETS) controls in California office buildings was carried out to obtain information of the type and distribution of ETS controls in office buildings and to evaluate the effectiveness of various ETS controls. A total of 118 smoking areas in 111 county and city buildings were inspected to collect information on the type of ETS controls. Only 31% of the smoking areas inspected were physically separated from nonsmoking areas with full floor-to-true-ceiling walls, 25% exhausted air to the outside, and 38% did not recirculate air to non-smoking areas. A total of 23 smoking areas and their adjacent non-smoking areas in 21 buildings were monitored for nicotine and fluorescent particulate matter (FPM). A tracer gas, sulfur hexafluoride (SF6), was released in smoking areas to measure the air leakage from smoking areas to adjacent non-smoking areas. The measurements of nicotine, FPM, and SF6 have shown large variations of the effectiveness of ETS controls. The least effective type of smoking area studied were open areas with no physical barriers between smoking and nonsmoking areas, no exhaust to the outside and no return air separation. On the contrary, smoking rooms with three ETS controls (i.e., physical separation, exhaust to outside, and no air recirculation) were the most effective design in containing ETS within smoking areas.

California↗

PubMed2001

Multiple actinomyces brain abscesses: case report.

A case of multiple cerebral abscesses caused by actinomyces is reported in a 37 year old male with mucoepidermoid carcinoma of the right lung. In conjunction with penicillin, sulfonamide and erythromycin, the patient underwent stereotactic surgery for aspiration of the brain abscesses under (CT). The bacteria, considered to originate from the right lung, were identified from the abscess material obtained at surgery. Using proper therapy to control infection and intracranial pressure is important. A lon g term follow up with frequent computerised tomography evaluation has been conducted and the patient outcome has been successful recovery.

Actinomycosis↗

PubMed2001

The zebrafish space cadet gene controls axonal pathfinding of neurons that modulate fast turning movements.

All vertebrates depend on neural circuits to produce propulsive movements; however, the contribution of individual neural cell types to control such movements are not well understood. We report that zebrafish space cadet mutant larvae fail to initiate fast turning movements properly, and we show that this motor phenotype correlates with axonal defects in a small population of commissural hindbrain neurons, which we identify as spiral fiber neurons. Moreover, we demonstrate that severing spiral fiber axons produces space cadet-like locomotor defects, thereby providing compelling evidence that the space cadet gene plays an essential role in integrating these neurons into the circuitry that modulates fast turning movements. Finally, we show that axonal defects are restricted to a small set of commissural trajectories, including retinal ganglion cell axons and spiral fiber axons, and that the space cadet gene functions in axonal pathfinding. Together, our results provide a rare example in vertebrates of an individual neuronal cell type that contributes to the expression of a defined motor behavior. Movies available on-line

Animals↗

PubMed2000

Dynamic effects of self-efficacy on smoking lapse and relapse.

Self-efficacy (SE) is thought to be critical to success in smoking cessation both as an individual difference and as a dynamic process after a quit attempt. In this study, 214 smokers used palm-top computers to record day-to-day variations in SE during 4 weeks after quitting. SE remained at high and stable levels prior to a 1st lapse but decreased and became more variable thereafter. The authors used event history models with time-varying covariates to assess the effect of daily SE on lapse and relapse risk. Daily SE measures predicted an initial lapse on the subsequent day. However, this relationship was accounted for by stable baseline differences in SE (assessed by questionnaire), rather than by day-to-day dynamics in SE. Progression from 1st lapse to relapse was also examined. In this instance, daily SE predicted subsequent relapse risk, even when baseline SE and concurrent smoking were accounted for, suggesting the importance of SE dynamics for this stage of the relapse process.

Adult↗

PubMed2000

Comparative efficacy of 24-hour and 16-hour transdermal nicotine patches for relief of morning craving.

AIMS: To compare a transdermal nicotine patch designed for 24-hour wear with one designed for 16-hour wear for relief of craving and withdrawal, particularly in the morning hours. DESIGN: Smokers were randomly assigned to use one of two common patch regimens: NicoDerm/NiQuitin (24-hour wear, 21 mg nicotine) or Nicotrol/Nicorette (16-hour wear, 15 mg). In a double-dummy design, participants wore two patches during the day, one active, one placebo and one patch while sleeping. SETTING: A smoking cessation research clinic. PARTICIPANTS: Two hundred and forty-four smokers who suffered morning cravings. INTERVENTION: Two patch formulations approved and marketed for over-the-counter use in the US--NicoDerm CQ (labeled as 21 mg over 24 hours) and Nicotrol (labeled as 15 mg over 16 hours)--were each used according to its instructions. Smokers also received behavioral counseling. MEASUREMENTS: For a week of baseline and 2 weeks after quitting, smokers used palm-top computers to assess craving and withdrawal symptoms several times each day. FINDINGS: The 21 mg/24-hour patch yielded consistently better control of craving, not only during the morning hours, but throughout the day, and over the 2-week period of abstinence. Additionally, the 21 mg/24-hour patch yielded greater reductions in anxiety, irritability and restlessness. Smokers using the 21 mg/24-hour dosing regimen also experienced longer abstinence than those using the 15 mg/16-hour patch. CONCLUSIONS: These findings demonstrate that 24-hour dosing with a 21 mg patch affords superior relief of craving and withdrawal during the first 2 weeks of abstinence, when symptoms are at their peak, and when relapse is most likely. They confirm the importance of dosing parameters in nicotine replacement products.

Administration, Cutaneous↗

PubMed1999

Laser ablations reveal functional relationships of segmental hindbrain neurons in zebrafish.

Segmentation of the vertebrate brain is most obvious in the hindbrain, where successive segments contain repeated neuronal types. One such set of three repeated reticulospinal neurons--the Mauthner cell, MiD2cm, and MiD3cm--is thought to produce different forms of the escape response that fish use to avoid predators. We used laser ablations in larval zebrafish to test the hypothesis that these segmental hindbrain cells form a functional group. Killing all three cells eliminated short-latency, high-performance escape responses to both head- and tail-directed stimuli. Killing just the Mauthner cell affected escapes from tail-directed but not from head-directed stimuli. These results reveal the contributions of one set of reticulospinal neurons to behavior and support the idea that serially repeated hindbrain neurons form functional groups.

Animals↗

PubMed1998

Zebrafish as a model system for studying neuronal circuits and behavior.

Zebrafish are best known as a model system for studies of the genetics of development. They do, however, also offer many advantages for the study of neuronal circuitry because the larvae are transparent, allowing optical studies of neuronal activity and noninvasive photoablations of individual neurons. The combination of these optical methods with genetics through the use of mutant and transgenic lines of fish should make the zebrafish model a unique and powerful one among vertebrates. Here we review the strengths of the model and the possibilities it offers for studies of the neural basis of behavior.

Animals↗

PubMed1998

Identification and case management in an HMO of patients at risk of preterm labor.

We carried out a study of pregnant patients in a health maintenance organization to identify and provide case management of women at risk of preterm labor and to determine important risk factors for preterm labor in a managed care population. Data were collected on 794 women who completed an initial prenatal care visit at HealthAmerica of Pittsburgh between July 15, 1994, and March 31, 1995, and delivered at a local Pittsburgh hospital. The patients were assessed during an initial call to schedule their first prenatal visit and also at the 8- to 15-week and 24- to 28-week prenatal visits. Patients scoring 10 or higher on the risk assessment form were referred to a nurse case manager who provided education and support. Results of a logistic regression analysis suggest that the risk assessment tool was effective in identifying women at risk for preterm labor. "Physical/stressful work", as assessed by the patient, history of a prior preterm birth, and multiple gestation were all statistically significant predictors of preterm birth. Further research is needed to confirm the finding that physical or stressful work is a significant predictor of preterm births and to determine which aspects of the work may increase the patient's risk. This study was based on 8 months of data; however, additional program implementation is needed to evaluate fully the potential long-term benefits of the program.

Case Management↗

PubMed1998

Causes of unintentional deaths from carbon monoxide poisonings in California.

The purpose of this study was to determine the annual number and incidence of unintentional deaths from carbon monoxide (CO) poisonings in California and to identify specific factors that caused or contributed to the deaths. Unintentional CO deaths in California over a ten-year period (1979 to 1988) were identified from the database of the California Master Mortality File and coroners' investigation reports. Factors associated with unintentional CO deaths were determined based on the information from the investigation reports. The annual number of unintentional CO deaths varied from 27 to 58 over the ten years examined, with an average annual death incidence of 1.7 x 10(-6). Death rates were high among males and African-Americans. Alcohol appeared to be a factor in 31% of the cases. The types of combustion sources associated with unintentional CO deaths were: heating or cooking appliances; motor vehicles; charcoal grills and hibachis; small engines; and camping equipment. Factors associated with unintentional CO deaths interact in a complex way. To reduce the rate of unintentional CO deaths effectively, joint efforts involving several prevention methods are suggested.

Adolescent↗

PubMed1997

Dependence of myocardial hypothermia tolerance on sources of activator calcium.

To determine the relationship between cardiac hypothermia tolerance and the sources of activator calcium, we selectively modified either the sarcolemmal calcium permeability by nifedipine or the sarcoplasmic reticulum function by caffeine in papillary muscles from both the rat, as a cold sensitive model, and the ground squirrel, Citellus dauricus, a deep hibernator. Both force-interval relationship and cooling performance were investigated. At 25 degrees C, the slope of the force-interval curve of the ground squirrel was nearly double that of the rat. At shorter test intervals 0.5 muM nifedipine moved the curve down with little effect at longer intervals, and the curve slope increased. Caffeine (1 mM) decreased the peak force and eliminated its dependence upon test interval. When the temperature was lowered, rat preparations showed a marked increase of resting tension and aftercontraction between 7 and 12 degrees C and became inexcitable. In contrast, they maintained contractility down to a few degrees above 0 degrees C without aftercontraction and increased resting tension in the ground squirrel. In the rat nifedipine shortened the contractions, prevented the increase of resting tension, and minimized aftercontractions, with little improvement of contractility. Caffeine prolonged the contractions, caused a striking increase of resting tension and aftercontractions, and finally disabled the contractility at about 5-10 degrees C, even in the ground squirrel. We conclude that depressed calcium influx helps to prevent hypothermic calcium overload of the cardiac cells. Good function of the sarcoplasmic reticulum is essential for tolerance of hypothermia by cardiac cells. A suggestion that may improve the hypothermic tolerance of the myocardium from nonhibernators is postulated.

Adaptation, Physiological↗

PubMed1995

Participation of the protein Go in multiple aspects of behavior in C. elegans.

The goa-1 gene encoding the alpha subunit of the heterotrimeric guanosine triphosphate-binding protein (G protein) Go from Caenorhabditis elegans is expressed in most neurons, and in the muscles involved in egg laying and male mating. Reduction-of-function mutations in goa-1 caused a variety of behavioral defects including hyperactive movement, premature egg laying, and male impotence. Expression of the activated Go alpha subunit (G alpha o) in transgenic nematodes resulted in lethargic movement, delayed egg laying, and reduced mating efficiency. Induced expression of activated G alpha o in adults was sufficient to cause these phenotypes, indicating that G alpha o mediates behavior through its role in neuronal function and the functioning of specialized muscles.

Amino Acid Sequence↗

PubMed1995

Sensory regulation of male mating behavior in Caenorhabditis elegans.

C. elegans male mating behavior comprises a series of steps: response to contact with the hermaphrodite, backing along her body, turning around her head or tail, location of the vulva, insertion of the two copulatory spicules into the vulva, and sperm transfer. By ablation of male-specific copulatory structures and their associated neurons, we have identified sensory structures and neurons that participate in each of these steps: the sensory rays mediate response to contact and turning; the hook, the postcloacal sensilla, and the spicules mediate vulva location; the spicules also mediate spicule insertion and regulate sperm transfer. Generally, successful completion of each step places the male in a position to receive a cue for the next step in the pathway. However, the high degree of sensory regulation allows the male to execute some steps independently.

Animals↗

PubMed1995

Relation between residential radon concentrations and housing characteristics. The Cracow Study.

The survey on indoor radon exposure was undertaken to explain whether the excess in lung cancer deaths in Cracow city center may be attributed to this particular exposure. A total of 310 detectors was placed in households randomly chosen from three homogenous strata of residential buildings. The first stratum included house in the old city center constructed predominantly out of the stone bricks. The second stratum covered area of the city with big apartment condominiums built out of concrete blocks. The third stratum consisted of single family houses located in a suburban area. From each of these residency strata a random sample of equal number of households has been chosen and the radon detectors were placed in households located at different levels of buildings. The three-month radon sampling data were used to determine the distribution of various levels of radon in the households. In the measurement of radon exposure the Landauer alpha-track samplers were used. The data collected show that the best single predictor of indoor radon concentrations was type of building. Other variables found to be associated significantly with indoor concentrations were household level in the building and house age. In general, residences with a concrete slabs and dwellings with rarely-opened windows were found to have slightly higher radon concentrations.

Air Pollution, Indoor↗

PubMed1994

Correlation between meteorological conditions and mutagenicity of airborne particulate samples in a tropical monsoon climate area from Kaohsiung City, Taiwan.

Kaohsiung is a city of 1.5 million located in the southern part of Taiwan. It has a serious air pollution problem mainly attributable to much industrial and commercial activity. In order to estimate the effects of traffic, season, and meteorological conditions on the mutagenicity of Kaohsiung City's urban ambient particulate matter, 624 airborne particulate samples were collected on a weekly basis from 12 locations for an entire year. The mutagenic potential of acetone extracts of air samples was evaluated by the Salmonella/microsomal test with S. typhimurium TA98 in the presence and absence of S9 mixtures. The air samples from November 1990 showed the highest direct and indirect mutagenicity among the 12 months, whereas those from June and July 1991 had the lowest direct and indirect mutagenic activity, respectively. The mutagenicity showed a good correlation with amounts of the acetone extractable matter of airborne particulates. The meteorological conditions, monthly mean precipitation, and wind speed also showed a good correspondence with mutagenicity. Wind direction and temperature had a moderate relationship. The major mutagenic fractions of air samples that had the highest mutagenic activity in a month were purified using Sephadex LH-20 column chromatography, and the contents of PAHs, 1-NP, and DNPs were analyzed by HPLC. The characteristic concentration ratios of PAHs indicated that, for the main pollution sources of airborne particulates from Kaohsiung city, the mobile sources were more important than the stationary ones. The total amounts of 1-NP and DNPs in airborne particulates seemed to correspond to their mutagenicity. Although the total amounts of 1-NP and DNPs in the air samples correlated with their mutagenicity, the major mutagenic chemicals in the airborne particulate samples from Kaohsiung City need further investigation.

Air Pollutants↗

PubMed1993

Unintentional carbon monoxide deaths in California from charcoal grills and hibachis.

This study was carried out to determine the annual incidence rate of and factors associated with unintentional deaths due to carbon monoxide (CO) poisoning from charcoal grills/hibachis in California during 1979-1988. A search through the California Master Mortality File was conducted to identify all cases with ICD-9 codes related to unintentional CO deaths. Individual coroners' investigation reports were obtained from 42 counties and evaluated by three evaluators. After excluding miscoded and misclassified cases, 444 deaths were judged to be authentic cases of unintentional CO poisoning. Among them, 59 deaths found to be due to the improper use of charcoal grills/hibachis. An increasing but not statistically significant trend was observed over the 10-year period. The highest rates occurred among males, asians, blacks, and middle-aged (20-39) people. Fifty-four percent of the deaths occurred in motor vehicles and 46% in residential structures.

Accidents↗

PubMed1991

Annual average radon concentrations in California residences.

A study was conducted to determine the annual average radon concentrations in California residences, to determine the approximate fraction of the California population regularly exposed to radon concentrations of 4 pCi/l or greater, and to the extent possible, to identify regions of differing risk for high radon concentrations within the state. Annual average indoor radon concentrations were measured with passive (alpha track) samplers sent by mail and deployed by home occupants, who also completed questionnaires on building and occupant characteristics. For the 310 residences surveyed, concentrations ranged from 0.10 to 16 pCi/l, with a geometric mean of whole-house (bedroom and living room) average concentrations of 0.85 pCi/l and a geometric standard deviation of 1.91. A total of 88,000 California residences (0.8 percent) were estimated to have radon concentrations exceeding 4 pCi/l. When the state was divided into six zones based on geology, significant differences in geometric mean radon concentrations were found between several of the zones. Zones with high geometric means were the Sierra Nevada mountains, the valleys east of the Sierra Nevada, the central valley (especially the southern portion), and Ventura and Santa Barbara Counties. Zones with low geometric means included most coastal counties and the portion of the state from Los Angeles and San Bernardino Counties south.

Air Pollution, Indoor↗

PubMed1991

Irritant effects of formaldehyde exposure in mobile homes.

This paper reports the irritant effects associated with formaldehyde exposures in mobile homes. Week-long, integrated formaldehyde concentrations were measured using passive monitors in summer and winter while the mobile home residents continued their normal activities. Information on acute health problems, chronic respiratory/allergic illnesses, smoking behavior, demographic variables, and time spent at home was obtained on over 1000 individuals during the sampling period. Measured formaldehyde concentrations varied from under the limit of detection (0.01 ppm) to 0.46 ppm. Formaldehyde exposure was estimated for each individual by multiplying the concentration measured in his or her home by the time he or she spent at home. Irritant effects were found to be associated with formaldehyde exposure after controlling for age, sex, smoking status, and chronic illnesses using a logistic procedure. Some of the interaction terms found to be significant indicated that there were synergistic effects between formaldehyde exposure and chronic health problems.

Adolescent↗