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Biomedical subjects

J Woo

Publications and source records attributed to J Woo.

At least 19 recordsLinked to original sources
PubMed2003

Identification of novel genes expressed during spermatogenesis in stage-synchronized rat testes by differential display.

The molecular mechanism regulating spermatogenesis at different developmental stages remains largely unknown. In a vitamin A-deficiency (VAD) rat model, five distinct histologically defined, stage-synchronized testes: (i) resting spermatogonia and preleptotene spermatocytes at Day 0 of post-vitamin A treatment (PVA); (ii) early pachytene spermatocytes at Day 7 PVA; (iii) late pachytene at Day 15 PVA; (iv) round spermatids at Day 25 PVA; and (v) elongated spermatids at Day 35 PVA were used to study gene expression profiles by mRNA differential display. Twenty-four differentially expressed cDNA fragments were identified and cloned; oligonucleotide sequence analyses indicated that there are 12 novel gene sequences, half of which share no apparent match in current GenBank/EMBL databases. Other 12 VAD clones share sequence homology to membrane channel and transport, transcription and translation, cell cycle and morphogenesis, inducer and transducer, surface or secreted glycoproteins or enzymes, and other miscellaneous molecules. Semi-quantitative RT-PCR analyses against different stages of VAD testes demonstrated: (i) restricted expression of VAD1.2 and 1.3 (novel) on Day 25 PVA when round spermatids form; (ii) escalating pattern of VAD12 (Cx43) in Sertoli cells; and (iii) relative constant levels of VAD4 (A5D3), VAD26.1 (ribonuclease), and VAD27 (GRP8) in spermatogenesis.

Animals↗
PubMed2003

Areal and volumetric bone density in Hong Kong Chinese: a comparison with Caucasians living in the United States.

It is a common perception that Asians have lower bone density than Caucasians. However, such relationships could be confounded by bone size. In this study, the skeletal status of a convenience sample of 482 men and 887 women living in Hong Kong is compared with published data for Caucasians living in Rochester, Minnesota. Areal bone mineral density (BMD, g/cm(2)) and volumetric bone mineral apparent density (BMAD, g/cm(3)) were determined for the lumbar spine and proximal femur, using the Hologic QDR 2000 instrument. Cross-calibration was performed by measuring a common phantom, and the Hong Kong data were adjusted by a multiplication factor. Lumbar spine and femoral neck BMD and BMAD of Chinese men and women were all significantly lower ( P<0.001 by t-test) than those of Caucasians, but the differences in BMAD were on average only about half the size of the differences in BMD. For instance, in postmenopausal Chinese women, BMD at the femoral neck and lumbar spine were 15.2% and 18.8% lower respectively, but BMAD at the femoral neck and lumbar spine were only 7.8% and 12.4% lower respectively. Similar trends were observed in men. After adjusting for age, body height and weight, the difference in BMAD between Caucasians and Chinese was further reduced and only statistically significant among postmenopausal women and among men younger than age 50 years for the lumbar spine. For instance, the adjusted BMAD in postmenopausal Chinese women at the femoral neck and lumbar spine were 3.9% ( P=0.03 by ANCOVA) and 7.3% ( P<0.001 by ANCOVA) lower respectively, while the adjusted BMAD at the lumbar spine for Chinese men younger than 50 years was 11.7% lower ( P<0.01 by ANCOVA). Predictors of BMAD in Hong Kong Chinese women include body weight, age at menarche, cigarette smoking, and oral contraceptive use ( P<0.001), while body weight was the only independent predictor of BMAD in Hong Kong Chinese men ( P<0.001). We conclude that bone density is lower in Hong Kong Chinese men and women than in Caucasians, although such differences were attenuated by adjustments for bone size, body weight and height.

Adult↗
PubMed2003

Genetic and environmental risk factors and their interactions for Parkinson's disease in a Chinese population.

The interaction between genetic and environmental factors for PD was examined in a Chinese population. It was found that although the intron 2 MAOB (GT)(n) repeat polymorphism was not associated with PD in the population, a relationship might have been masked by the "protective effect" of tea drinking. In individuals who did not drink tea (<1 cup/day), the possession of short length < or = 178 bp (GT)(n) alleles conferred a borderline significant increased risk for PD (adjusted OR=1.47; C.I.=1.03-2.1). As the extent of tea consumption increased, the association between the < or = 178 bp allele and PD disappeared. This result suggests that the MAOB gene may be associated with PD in Chinese if the putative protective effect of tea drinking is taken into account. The significance of this finding is unclear as the study may be limited because of its marginal significance and limited numbers. However, it does demonstrate the importance of considering putative positive and negative environmental risk factors in any examination of genetic risk factors for PD.

Asian People↗
PubMed2003

Relationship of urinary sodium/potassium excretion and calcium intake to blood pressure and prevalence of hypertension among older Chinese vegetarians.

OBJECTIVE: To examine the associations of dietary sodium and potassium, as reflected by the urinary sodium/potassium excretion, and calcium intake with blood pressure and the prevalence of hypertension among older Chinese vegetarians in Hong Kong. DESIGN: Cross-sectional study. SETTING: Research clinic in a teaching hospital in Hong Kong. SUBJECTS: A total of 111 ambulatory vegetarians over the age of 55 were recruited from members of religious organizations or old age hostels. MAIN OUTCOME MEASURES: Hypertension was defined as supine blood pressure >140/90 mmHg or a history of hypertension. Dietary sodium, potassium and calcium intakes were assessed by 24 h recall method or fasting urinary sodium or potassium/creatinine ratios. RESULTS: Seventy-one subjects (64%) were found to have hypertension. Compared with normotensive subjects, hypertensive subjects had lower calcium intake (411+/-s.d. 324 vs 589+/-428 mg, P=0.04), but higher urinary sodium/creatinine ratio (32.6+/-19.3 vs 21.0+/-12.4, P=0.00) and sodium/potassium ratio (4.7+/-2.8 vs 3.4+/-2.3, P=0.02). Among 88 subjects not taking diuretics or antihypertensive drugs, systolic blood pressure was related to calcium intake (r=-0.40), urinary sodium/creatinine ratio (r=0.39), urinary sodium/potassium ratio (r=0.30) and age (r=0.23). Diastolic blood pressure was related to urinary sodium/creatinine (r=0.29). Twenty-three subjects with high urinary sodium/potassium and low calcium intake and 16 subjects with low urinary sodium/potassium ratio and high calcium intake differed markedly with respect to systolic blood pressure (159+/-26 vs 130+/-15 mmHg) and prevalence of hypertension (78% vs 25%). CONCLUSIONS: Older Chinese vegetarians are predisposed to hypertension because of their sodium-rich but calcium-deficient diets.

Aged↗
PubMed2003

Diet and glucose tolerance in a Chinese population.

BACKGROUND: Associations between dietary factors and glucose tolerance observed in Caucasian populations may not be applicable to Chinese populations, since the traditional Chinese diet contains plentiful vegetables and is rice-based (which has a lower glycemic index than potatoes). To address this question, the dietary patterns in 988 Hong Kong Chinese subjects with normal and impaired glucose tolerance, and diabetes, were examined in a cross sectional survey to determine if there is any association between diet and glucose tolerance. METHOD: A stratified random population sample of 988 subjects (488 male, 500 female) was recruited. A food frequency questionnaire was used to determine dietary intake, and glucose tolerance was examined using the glucose tolerance test and the WHO criteria used to classify subjects into the three glucose tolerance categories. RESULTS: Using the standardized world population of Segi, the prevalence rate for DM was 6.6% for men and 5.7% for women; and for IGT 10.3% for men and 15.4% for women aged 30-64 y. Abnormal glucose tolerance is associated with female gender, older age, lower educational attainment and higher body mass index (BMI). No clear pattern of association with dietary factors was observed after adjusting for confounding factors. However, if subjects with BMI>or=25 kg/m(2) were excluded, an increase in mean consumption of rice/noodles/pasta per week was observed in the DM group, after adjusting for total energy intake and other confounding factors. No association between dietary variety, which has been linked with body fatness, and glucose tolerance, was observed. CONCLUSION: Dietary habit may not be a strong risk factor for the development of glucose intolerance in Chinese populations, given the favorable features of the Chinese diet. The high consumption of rice in the DM subjects who are of normal BMI suggests that further studies examining glycemic indices of Chinese food items may be beneficial. Obesity still remains the most important predisposing factor.

Adult↗
PubMed2003

Efficacy of a specially designed hip protector for hip fracture prevention and compliance with use in elderly Hong Kong Chinese.

BACKGROUND: Hip protectors, while effective in prevention of hip fractures, have been designed for a Caucasian body build and may not be suitable for Asian subjects living in a subtropical climate. OBJECTIVE: Hip protectors and accompanying shorts were specially designed for use for the Chinese body build and subtropical climate, and tested for compliance and efficacy in fracture prevention. METHOD: A pragmatic study examining compliance with the wearing of hip protectors, and effectiveness in preventing hip fractures (using a case control design), in 302 subjects wearing hip protectors and 352 control subjects. RESULTS: Overall compliance varied from 55 to 70%. The relative risk for hip fracture was 0.18 (0.04-0.79), relative risk reduction 82%, and the number of subjects needing to wear a hip protector to prevent one fracture was 33 (19-117). CONCLUSION: Hip protectors adapted for use in Chinese people appear to reduce hip fractures in routine clinical practice.

Accidental Falls↗
PubMed2003

Ethical issues related to the use of placebo in clinical trials.

Controversy exists regarding the ethics of using placebo control groups in clinical trials when effective treatments exist. The debate was fuelled by the announcement of the fifth revision of the Declaration of Helsinki in 2000. This study reviews the history and scientific background surrounding the controversy and investigates the prevailing attitudes of Hong Kong researchers regarding this issue. The controversy has centred on several issues. The first involves the methodological superiority of placebo-controlled trials in discerning treatment effects. Secondly, it is unclear whether the treatment effects encompass absolute treatment effects (including placebo effects) or are confined to treatment-specific effects (excluding placebo effects). Thirdly, there are concerns that subjects in the placebo group could be exposed to a high risk for developing serious adverse events. Fourthly, it is unclear whether the standard of best available treatment should be local or international. Preliminary research findings suggest that the opinions of Hong Kong researchers are divided on the use of placebo control groups in clinical trials when effective treatment exists. Further research on the topic is therefore warranted, and training and consensus meeting may be necessary to minimise the confusion related to this issue.

Clinical Trials as Topic↗
PubMed2002

Independent effect of vitamin B12 deficiency on hematological status in older Chinese vegetarian women.

We have examined the independent effect of vitamin B(12) deficiency on hematological indices in older Chinese vegetarian women using a cross-sectional study design: 119 women older than 55 years who had been vegetarian for more than 3 years were studied. Fasting blood samples were taken for complete blood count, serum iron, total serum iron binding capacity, serum iron saturation, serum vitamin B(12), serum folate, serum methylmalonic acid levels (MMA), and renal function test. Subjects with iron deficiency (iron saturation <15%) and those with serum creatinine >150 mmol/L were excluded. The prevalence of definite vitamin B(12) deficiency (vitamin B(12) level < 150 pmol/L and MMA >or= 0.4 micromol/L) was 42%. Another 32.8% had possible vitamin B(12) deficiency (either criterion). The prevalence of iron deficiency was 10%. After exclusions, 96 subjects were further analyzed. Vitamin B(12) deficiency defined by serum vitamin B(12) and MMA was associated with a decrease in hemoglobin concentrations by up to 0.9 g/dL, but it was not associated with an increase in mean corpuscular volume (MCV). Serum MMA but not vitamin B(12) levels correlated inversely with hemoglobin and platelet counts and positively with MCV, after adjustment of confounding factors. However, the percentage of subjects with anemia did not increase significantly until serum MMA became >1.0 micromol/L. In conclusion, vitamin B(12) deficiency was associated with a significant decrease in hemoglobin concentration. However, anemia associated with vitamin B(12) deficiency was seldom macrocytic. We recommend that older vegetarians should be given vitamin B(12) supplements routinely.

Aged↗
PubMed2002

Vitamin D receptor start codon polymorphism (Fok I) and bone mineral density in Chinese men and women.

The relationship between Fok I polymorphism of the vitamin D receptor start codon, bone mineral density (BMD) and vertebral fractures was studied in 684 Chinese men and women. A significant trend was observed only in Chinese women aged 70-79 years. The mean BMD at the total body was 0.85 +/- 0.01 g/cm2, 0.82 +/- 0.01 g/cm2 and 0.84 +/- 0.01 g/cm2 for elderly women of the FF, Ff and ff genotypes respectively (p = 0.06 by ANOVA). Similar but statistically non-significant trends were observed at the hip and spine. However, no association between BMD and the Fok I genotype was observed in younger women (aged 50-59 years) and elderly men (aged 70-79 years). In all study groups, there was no effect of an interaction between Fok I polymorphism and calcium intake on BMD (p > 0.05 for the interaction effects by two-way ANOVA). No significant association was observed between Fok I polymorphism and vertebral fracture in elderly men or women (p > 0.05 by the chi-square test). We conclude that the Fok I polymorphism may have a weak effect on the BMD of elderly Chinese women.

Age Factors↗
PubMed2002

Baseline BMD and bone loss at distal radius measured by peripheral quantitative computed tomography in peri- and postmenopausal Hong Kong Chinese women.

The current study was designed to investigate the rate of bone loss in distal radius and its association with baseline volumetric bone mineral density (BMD) and years since menopause (YSM) in peri- and postmenopausal women using precise and multislice peripheral quantitative computed tomography (pQCT; Densiscan 2000). Two hundred and five healthy Hong Kong Chinese perimenopausal ( n = 26) and postmenopausal ( n = 179) women within 10 years of the onset of menopause were recruited. Anthropometric parameters and menstrual status were also measured. The linear regression model derived from the baseline volumetric BMD revealed a significant and slightly better correlation with YSM than age, with a YSM-related annual decline of 2.56%, 1.82% and 0.65% in trabecular BMD (tBMD), integral BMD (iBMD) and cortical BMD (cBMD), respectively. Follow-up measurements after a time interval of 12 months showed that the rate of bone loss was higher than the annual decline in BMD calculated from the baseline BMD, with decreases of 2.89%, 2.16% 0.91% in tBMD, iBMD and cBMD, respectively. Baseline BMD was associated with age or YSM ( r ranges from -0.283 to -0.502; p<0.001 in all cases), but no relationship was found between annual rate of bone loss and age or YSM. The rate of bone loss did not correlate with baseline volumetric BMD values or YSM after dividing the subjects into fast bone losers (with annual tBMD loss > or =3%), normal bone losers (with annual tBMD loss > or = 1% but <3%) or slow bone losers (with annual tBMD loss <1%). The rate of bone loss was greater in both trabecular and cortical bone of postmenopausal women within the first 3 menopausal years but was only significant in the iBMD as compared with perimenopausal and postmenopausal women over 7 years after onset of menopause. The percentage distribution of slow and fast bone losers was not found to be associated with YSM. As a total of only 4 fracture cases were documented, the study could not provide conclusive information on whether perimenopausal and early postmenopausal baseline volumetric BMD or rate of bone loss determines the development of osteoporosis or fracture occurrence.

Adult↗
PubMed2002

Lack of association between CYP1A1 polymorphism and Parkinson's disease in a Chinese population.

Apart from very few families who have a direct cause from genetic mutation, causes of most Parkinson's disease (PD) remain unclear. Many allelic association studies on polymorphism of different candidate genes have been studied. Although these association studies do not imply a causal relationship, it does warrant further studies to elucidate the pathophysiologic significance. CYP1A1 polymorphisms have been reported to be associated with PD in a Japanese population sample. Since CYP1A1 transforms aromatic hydrocarbons into products that may be neurotoxic and perhaps lead to PD, we therefore undertook a study to look at the possible association of CYP1A1 polymorphism and PD in a Chinese population. Contrary to the Japanese result, we did not find any statistically significant difference between the PD group and the control group in our study with a bigger sample size.

Aged↗
PubMed2002

Milk supplementation prevents bone loss in postmenopausal Chinese women over 3 years.

Previously published results from a 2 year randomized, controlled clinical trial on supplementing the diet of postmenopausal Chinese women with high-calcium milk powder (containing 800 mg of calcium) showed that bone loss, as measured by bone mineral density (BMD), was prevented. To determine whether the effect of calcium supplementation could be sustained, the study was extended for 1 additional year. According to the intention-to-treat analysis, the differences in the rate of bone loss (percentage decrease in control group--percentage decrease in milk supplementation group) in the third year of the study were: total body BMD, 0.23% (95% confidence interval [CI] 0.07%-0.39%); total spine BMD, 0.31% (95% CI - 0.02%-0.65%); and total hip BMD, 0.44% (95% CI 0.19%-0.69%). Analysis by the per-protocol method showed a similar effect size. These results indicate that the effects of milk supplementation in preventing bone loss in postmenopausal Chinese women were sustained after 2 years.

Animals↗
PubMed2002

Total daily energy expenditure in wasted chronic obstructive pulmonary disease patients.

OBJECTIVES: To investigate total daily energy expenditure in chronic obstructive pulmonary disease (COPD) patients during a rehabilitation programme. DESIGN: Observational study involving a case and a control group. SUBJECTS: Ten COPD patients (six with body mass index (BMI) <18.5 kg/m(2) and four with BMI >18.5 kg/m(2)) were evaluated for their energy expenditure profile. Four additional healthy age-matched volunteers were also included for methodology evaluation. INTERVENTIONS: Measurements of total daily energy expenditure (TEE), resting energy expenditure (REE) and diet-induced thermogenesis (DIT) and energy intake were undertaken by indirect calorimetry and bicarbonate-urea methods and dietary records. RESULTS: REE in COPD patients was not significantly different from that predicted by the Harris-Benedict equation. Before the exercise day the mean TEE was 1508 kcal/day and physical activity level (PAL as calculated by TEE/REE) was 1.52. On the exercise day the TEE increased to 1568 kcal/day and PAL was 1.60, but neither of these changes were significant. The energy cost of increased physical activity during rehabilitation exercise was estimated to be 191 kcal/day. No significant change was found in DIT between the two patient groups. However, overall energy balances were found to be negative (-363 kcal/day). CONCLUSION: The rehabilitation programme did not cause a significant energy demand in COPD patients. TEE in COPD patients was not greater than in free-living healthy subjects. Patients, who were underweight, did not have a higher TEE than patients with normal weight. This suggested that malnutrition in COPD patients was not due to an increased energy expenditure. On the other hand, a significant negative energy balance due to insufficient energy intake was found in seven out of 10 patients.

Aged↗
PubMed2002

Is waist circumference a useful measure in predicting health outcomes in the elderly?

OBJECTIVE: To examine the effect of age on the relationship between body mass index (BMI) and waist circumference (WC), and the usefulness of BMI, WC and waist-hip ratio (WHR) in predicting mortality and cardiovascular risk in the elderly population. DESIGN: Longitudinal observational study of 36 months duration. SUBJECTS AND METHOD: A stratified random sample of 2,032 Chinese subjects (990 male, 1,033 female) mean age (s.d.) 80.1 (7.5), interviewed and examined at baseline and after 36 months. Deaths and presence of diabetes mellitus and hypertension were documented. A younger data set of 1,010 subjects (500 male, 510 female), mean age (s.d.) 45.5 (11.6), was used for comparison of the BMI-WC relationship between younger and older subjects. In predicting outcomes using different values of BMI, WC and WHR, receiver operating characteristic curve analysis was used to derive cut-off values with optimal sensitivity and specificity, and the likelihood ratios for mortality, diabetes and hypertension for different anthropometric values were plotted. RESULTS: The waist circumference values corresponding to BMI values of 25 and 30 kg/m(2) were higher in elderly (92 and 103 cm for men; 88 and 99 cm for women) compared with younger subjects (85 and 97 cm for men; 78 and 88 cm for women). BMI and WC are inversely associated with mortality, in both men and women, positively associated with diabetes in men but not in women. WC was positively associated with hypertension in men and women. WHR was not associated with any outcome measures. The anthropometric measurement at the point of intersection of the likelihood curves for mortality and diabetes may be considered the optimum value, being BMI=21 kg/m(2) for men and 25 kg/m(2) for women, WC between 80 and 85 cm, and WHR 0.88-0.90. CONCLUSION: Waist measurement values for predicting health outcomes in elderly people aged 70 y and over are different compared with younger subjects, and have similar predictive accuracy compared with body mass index. Waist-hip ratio is not a useful predictor.

Aged↗
PubMed2002

Prevalence of wheeze, bronchial hyper-responsiveness and asthma in the elderly Chinese.

BACKGROUND: Asthma is a common health problem affecting patients of all ages. Because of the ease of sampling, epidemiological studies have concentrated mainly on the paediatric and general population. OBJECTIVE: This study aimed to determine the prevalence of wheeze, bronchial hyper-responsiveness and asthma amongst our elderly population and deduce any clinical and laboratory risk factors that might identify elderly asthmatics at an earlier stage. METHODS: Two thousand and thirty-two elderly Chinese aged > or = 70 years, randomly selected from a registered list of all recipients of Old Age and Disability Allowances in Hong Kong, were administered a questionnaire on lung health. Two hundred and fifty subjects were invited to attend our laboratory for skin tests and pulmonary function tests and 179 agreed. Of these, 173 (96.6%) and 176 (98.3%) had eosinophil count and serum IgE levels measured, respectively. Two definitions of asthma were used: (1) bronchial hyper-responsiveness (BHR) plus current wheeze, and (2) history of wheezing without previous diagnostic labels of emphysema or chronic bronchitis. RESULTS: Fifteen patients (out of 179: 8.4%) reported wheezing over the past 1 year. Fifty-one patients (28.5%) demonstrated BHR on spirometry or histamine challenge tests. Seven patients had both symptoms of wheezing and evidence of BHR. The prevalence of asthma using this definition is therefore 3.9% (95% CI 1.6-7.9%). Nine patients had symptoms of wheezing without previous diagnostic labels of chronic bronchitis or emphysema and, using this definition, the prevalence is 5.0% (95% CI 2.3-9.3%). Using multiple logistic regression studies, sex, social class, age, smoking habits, serum IgE levels and eosinophil counts did not predict a diagnosis of asthma using either definition. We found no association between a positive skin test and any respiratory symptoms or illnesses including asthma. CONCLUSION: Wheeze, bronchial hyper-responsiveness and asthma are prevalent amongst our elderly population. However, there were no identifiable demographic and laboratory risk factors in this study that may help us predict a diagnosis of asthma.

Aged↗
PubMed2002

Thermoluminescence of PbWO4 irradiated with UV light.

PbWO4 single crystals were grown by the Czochralski method in argon and air. The glow curves induced by UV light and the absorption spectra of PbWO4 annealed at various temperatures were measured. The glow curves of PbWO4 were strongly dependent on the growing atmospheres. The activation energies of the 110 K peak of PbWO4 grown in argon and the 122 K peak of PbWO4 grown in air were calculated to be 0.23 eV and 0.29 eV, respectively. The ratio of the 2.76 eV emission band to the 2.48 eV or 2.26 eV emission bands of the PbWO4 grown in air was smaller than that of the PbWO4 grown in argon. The glow curve of PbWO4 grown in argon was similar to that of PbWO4 grown in air when the annealing temperatures were increased.

Air↗
PubMed2001

Virulence differences between two field isolates of feline immunodeficiency virus (FIV-APetaluma and FIV-CPGammar) in young adult specific pathogen free cats.

The goal of this study was to identify a strain of feline immunodeficiency virus (FIV) that would be more virulent for adult cats than the prototype FIV-APetaluma and, thereby, enhance the FIV infection model for HIV-1 related research. Diehl et al. reported that one clade C strain of FIV, FIV-CPGammar, was more virulent than other known FIV isolates. Mortalities from 58 to 100% were reported for kittens 12 weeks of age and less following intravenous inoculation. A more variable and somewhat less virulent disease course was observed in neonatal to 8-10-week-old kittens infected orally, intravaginally or intrarectally with this same isolate (Obert and Hoover, 2000). However, no studies have been done with FIV-CPGammar in adult cats. Therefore, the virulence of FIV-CPGammar for young adult cats was compared to that of FIV-APetalulma, the original FIV isolate. One group of five cats were inoculated intraperitoneally with 470 TCID(50) of FIV-CPGammar in the form of pooled plasma from acutely infected cats, while a second group was infected with plasma containing the 750 TCID50 of FIV-APetaluma. The cats were observed for 20 weeks for gross signs of disease, hematologic abnormalities, time of antibody appearance, and plasma and peripheral blood mononuclear cell (PBMC) associated virus levels. Viral RNA and proviral DNA were measured by a real-time PCR, sensitive to 50 copies per milliliter. The only outward sign of disease was lymphadenopathy, which occurred at a similar time and intensity in both groups of cats. Cats infected with FIV-CPGammar were more likely to be neutropenic and lymphopenic during the first 10-12 weeks of infection than cats infected with FIV-APetaluma. Both groups of cats showed similar overall declines in absolute mean CD4 cell counts and identical concomitant increases in CD8 cells. CD4/CD8 cell ratios were also similar. Antibody, as measured by an ELISA against recombinant FIV-TM antigen, appeared in all cats by 4 weeks post-infection. The most significant differences were in plasma viral RNA and PBMC proviral DNA levels. Cats infected with FIV-CPGammar had up to 100 times higher mean levels of viral RNA during the first few weeks of infection than cats infected with FIV-APetaluma. This difference was also mirrored in levels of proviral DNA in PBMC, which were significantly higher in the FIV-CPGammar infected cats. Plasma viral RNA and PBMC proviral DNA levels were virtually identical in both groups of cats at 20 weeks post-infection. However, proviral DNA in tissues such as thymus and popliteal lymph nodes was 10-fold or so higher in FIV-CPGammar infected cats at 20 weeks and histopathologic lesions were more severe. Based on these various parameters, we concluded that FIV-CPGammar was more virulent than FIV-APetaluma in young adult cats during the 20-week study period. However, we were not able to recreate the severe and rapidly progressive disease previously reported for kittens, suggesting an age-related resistance similar to that observed previously for FIV-APetaluma (George et al., 1993).

Animals↗