PubMed Health⌕ Search

Biomedical subjects

C Loo

Publications and source records attributed to C Loo.

9 recordsLinked to original sources
PubMed2006

Target tracking in infrared imagery using weighted composite reference function-based decision fusion.

In this paper, we propose a novel decision fusion algorithm for target tracking in forward-looking infrared image sequences recorded from an airborne platform. An important part of this study is identifying the failure modes in this type of imagery. Our strategy is to prevent these failure modes from developing into tracking failures. The results furnished by competing ego-motion compensation and tracking algorithms are evaluated based on their similarity to a target model constructed using the weighted composite reference function.

Algorithms↗
PubMed2001

Effects of a 2- to 4-week course of repetitive transcranial magnetic stimulation (rTMS) on neuropsychologic functioning, electroencephalogram, and auditory threshold in depressed patients.

BACKGROUND: The safety of repetitive transcranial magnetic stimulation (rTMS) has only previously been formally studied in volunteers receiving a single session of stimulation or in a small number of depressed subjects receiving a 2-week treatment course. This study examined safety issues in depressed subjects receiving up to 4 weeks of rTMS. Efficacy results from this study have been previously reported. METHODS: Eighteen subjects with DSM-IV major depression participated in a 2-week, parallel, double-blind, sham-controlled study of rTMS treatment. Twelve subjects then went on to receive 4 weeks active rTMS in an open follow-up. We examined the effects of rTMS on neuropsychologic function (up to 4 weeks), auditory threshold (up to 6 weeks exposure to rTMS noise), and an electroencephalogram (after 2 weeks). Data were analyzed by repeated measures analysis. RESULTS: There were trends for improvement in neuropsychologic performance, probably due to practice effects. No mean changes in auditory threshold occurred, but two patients showed mild high-frequency hearing loss after several weeks of rTMS. Electroencephalograms in two patients, one of whom had sham stimulation, showed minor abnormality. CONCLUSIONS: No significant mean deficits were demonstrated in this cohort. Overall, rTMS for up to 4 weeks is safe, but individual results suggest caution and the need for further investigation of the safety of several weeks of rTMS.

Adult↗
PubMed2001

Karyotype, phenotype and parental origin in 19 cases of triploidy.

The parental origin of triploidy in 19 cases was examined by inheritance of DNA microsatellites and by methylation patterns of SNRPN or PW71 (where parents' blood was unavailable). The fetal and placental morphology on these cases was reviewed. The phenotype of the fetuses with non-mosaic triploidy was assessed in relation to the two types described by McFadden and Kalousek. Of the diandric fetuses three of the six showed mild-to-moderate symmetrical growth retardation and the other three had growth characteristics in accordance with their gestational ages. This study would suggest the fetal triploid 'Type 1' definition be modified to 'well grown to moderate symmetrical IUGR' to allow for such variation. In the digynic fetuses (McFadden/Kalousek Type 2) there were poor growth characteristics with IUGR being more severe and asymmetrical. The diandric fetuses were as common as digynic fetuses in this series. The ratio of diandric to digynic specimens was 11:8 but if only fetal specimens (not embryos or mosaic children) were included the ratio was 6:5. Many diandric conceptions end as partial moles but later in gestation diandric fetuses may be well grown. It is proposed that there may be a survival barrier for diandric fetuses early in gestation (possibly based on the proportion of vascularised placental villi), although once this is passed the diandric fetuses are comparatively more viable and better grown than digynic fetuses. In the XXY triploid fetuses, 5/6 had hypoplastic or ambiguous external genitalia (two were recorded as of female phenotype) as has been reported previously. In these, the gonadal histology was testicular in all the diandrics but in the single digynic XXY case, sex reversal was complete with normal uterus and Fallopian tubes and the gonads were histologically ovaries. Two triploid/diploid mosaics were proven to be due to digyny. The probable cause is delayed incorporation of the second polar body into a blastomere and there was evidence of identical alleles from the same sperm being present in both diploid and triploid cells. In one of these triploid/diploid mosaics in which there was a termination of pregnancy (TOP) after prenatal karyotyping the diploid cell line had trisomy 16 which was not evident in the triploid line. This trisomy was probably of post-zygotic origin and we suggest the fetus was rescued by the prominence of the triploid line.

Abortion, Spontaneous↗
PubMed2000

Subtyping depression by clinical features: the Australasian database.

OBJECTIVE: To distinguish psychotic, melancholic and a residual non-melancholic class on the basis of clinical features alone. Previous studies at our Mood Disorders Unit (MDU) favour a hierarchical model, with the classes able to be distinguished by two specific clinical features, but any such intramural study risks rater bias and requires external replication. METHOD: This replication study involved 27 Australasian psychiatrist raters, thus extending the sample and raters beyond the MDU facility. They collected clinical feature data using a standardized assessment with precoded rating options. A psychotic depression (PD) class was derived by respecting DSM-IV decision rules while a cluster analysis distinguished melancholic (MEL) and non-melancholic classes. RESULTS: The MELs were distinguished virtually entirely by the presence of significant psychomotor disturbance (PMD), as rated by the observationally based CORE measure, with over-representation on only three of an extensive set of 'endogeneity symptoms'. CONCLUSION: In comparison to PMD, endogeneity symptoms appear to be poor indicators of 'melancholic' type, confounding typology with severity. Results again support the hierarchical model.

Adult↗
PubMed2000

Tobacco use by youth: a surveillance report from the Global Youth Tobacco Survey project.

The Global Youth Tobacco Survey (GYTS) project was developed by the World Health Organization and the US Centers for Disease Control and Prevention to track tobacco use among youth in countries across the world, using a common methodology and core questionnaire. The GYTS is school based and employs a two-stage sample design to produce representative data on smoking among students aged 13-15 years. The first stage consists of a probabilistic selection of schools, and the second consists of a random selection of classes from the participating schools. All students in the selected classes are eligible for the survey. In 1999, the GYTS was conducted in 13 countries and is currently in progress in over 30 countries. This report describes data from 12 countries: Barbados, China, Costa Rica, Fiji, Jordan, Poland, the Russian Federation (Moscow), South Africa, Sri Lanka, Ukraine (Kiev), Venezuela, and Zimbabwe. The findings show that tobacco use in the surveyed age group ranged from a high of 33% to a low of 10%. While the majority of current smokers wanted to stop smoking, very few were able to attend a cessation programme. In most countries the majority of young people reported seeing advertisements for cigarettes in media outlets, but anti-tobacco advertising was rare. The majority of young people reported being taught in school about the dangers of smoking. Environmental tobacco smoke exposure was very high in all countries. These results show that the GYTS surveillance system is enhancing the capacity of countries to design, implement, and evaluate tobacco prevention and control programmes.

Adolescent↗
PubMed1999

Double-blind controlled investigation of transcranial magnetic stimulation for the treatment of resistant major depression.

OBJECTIVE: The efficacy and safety of left prefrontal repetitive transcranial magnetic stimulation (rTMS) for treating resistant major depression were examined in a double-blind, controlled study. METHOD: Eighteen medication-resistant depressed subjects were randomly assigned to 2 weeks of real or sham rTMS, then permitted up to 4 weeks of real rTMS. Effects on mood, neuropsychological function, EEG, and hearing were assessed. RESULTS: The groups receiving real and sham rTMS improved in mood significantly over the 2-week double-blind period, but there was no significant difference between groups. CONCLUSIONS: Repetitive transcranial magnetic stimulation did not provide significantly greater improvement than did sham treatment. A 4-week course of rTMS, as administered in this study, was safe.

Affect↗
PubMed1993

Surgical management of early invasive cancer of the cervix associated with pregnancy.

The simultaneous occurrence of carcinoma of the cervix in pregnancy is uncommon. In a prospective study of 397 patients undergoing type III radical hysterectomy for early invasive cancer of the cervix, 18 were pregnant at the time of surgery; 4 of these were operated after delivery elsewhere. Two others had a type I extrafascial hysterectomy. The incidence was 1 in 4077 deliveries. The clinical and histological characteristics of these patients are presented. Routine speculum examination and cervical cytology in all pregnant patients early in pregnancy are vital for early diagnosis. Bleeding in pregnancy should not automatically be assumed to be caused by pregnancy-related conditions. The strategies in surgical management are discussed. Radical hysterectomy in pregnancy is safe. No major complications were encountered; the mean blood loss was 1.4 liters. The incidence of pelvic node metastases was similar to that seen in nonpregnant patients. The overall 5-year survival rate was 77.7%. Of the 4 patients who died, 3 presented in the puerperium; all succumbed within 27 months. Poor histological prognostic features contributed to the significantly poorer survival in the puerperal patients (P = 0.0445). The 5-year survival in those presenting during the antepartum period (92.8%) was, however, similar to that in the nonpregnant patients. Metastases to the placenta or fetus were not encountered.

Adult↗
PubMed1978

The group assessment of interpersonal traits (GAIT): differentiation of measures and their relationship to behavioral response modes.

GAIT performances of undergraduates were rated by peers and professsional clinical psychologists from video tape. Two additional measures; Potential for Clinical Effectiveness, and Insight into the Client's Problem, were included with GAIT measures of Openness, Empathy, Acceptance, and Outgoing and were also rated. GAIT ratings of Empathy, Acceptance, Potential for Clinical Effectiveness were not well differentiated. The behavioral response modes of each participant in the Understander's role were analyzed and correlated with GAIT measures, Potential and Insight. Empathy was correlated with reflecting feelings and advice-giving questions and negatively correlated with dysfunctional questions and silence. Acceptance was correlated with nonverbal attending behavior and negatively correlated with dysfunctional questions. Outgoing was positively correlated with information-gathering questions and total questions. Insight was correlated with reflecting feelings and negatively correlated with silence. An Understander who was rated high on Potential for Clinical Effectiveness was active, made statements about or asked questions pertaining to the Discloser's feelings, asked advice giving questions, tended to have infrequent silences during the interaction, and did not ask digressive or dysfunctional questions. Finally, the importance of Outgoing suggests the salience of an activity dimension in judged Clinical Potential.

Adult↗