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Biomedical subjects

W T Lee

Publications and source records attributed to W T Lee.

At least 37 records · Page 2Linked to original sources
PubMed2000

Mitochondrial cytopathy combined with Fanconi's syndrome.

Severe muscle weakness in Fanconi's syndrome is rarely the result of mitochondrial cytopathy. We describe a rare case of a 9-year-old male with early onset of Fanconi's syndrome. He developed severe proximal muscle weakness exacerbated by hypokalemia and hypophosphatemia in childhood. The muscle biopsy revealed increased accumulation of abnormal mitochondria and fat droplets in histochemical stains and electron microscopy. Mitochondrial cytopathy cannot be excluded in Fanconi's syndrome with late onset of muscular impairment. Long-term follow-up of his clinical course is suggested to understand the natural history of this unusual case.

Acidosis, Renal Tubular↗
PubMed2000

Acute hemiplegia associated with herpes zoster infection in children: report of one case.

Herpes zoster infection has been rarely reported to cause angiitis of the central nervous system in children. We describe a 4-year, 8-month-old female with acute hemiplegia and central facial palsy 6 weeks after she had had zoster ophthalmicus. The findings of magnetic resonance angiography, the clinical picture, and a preceding history of herpes zoster ophthalmicus suggested zoster vasculitis. Herpes zoster vasculitis is thus another consideration when examining a child with acute hemiplegia and a recent herpes zoster infection.

Child, Preschool↗
PubMed2000

Congenital intracranial teratoma.

Congenital intracranial teratoma is a rare disease. A fetus with a congenital intracranial teratoma presenting with a disproportionately enlarged head at 27 weeks gestation is presented. Prenatal ultrasonography and fetal magnetic resonance imaging demonstrate a huge, heterogenous intracranial mass in the left supratentorial region, with the left cerebral hemisphere being compressed and flattened. The infant died of respiratory failure within 24 hours of birth at 28 weeks gestation. On postmortem examination the histologic report revealed an immature teratoma. Fetal MRI is helpful in the prenatal diagnosis and evaluation of intracranial tumor.

Brain Neoplasms↗
PubMed2000

Growth and nutrition of Hong Kong children aged 0-7 years.

OBJECTIVE: To study the early dietary practices in relation to growth of Hong Kong children from birth to 7 years. METHODOLOGY: One hundred and seventy-three full-term Hong Kong Chinese babies were recruited at birth and were followed up for anthropometric measurements using standardized methods and dietary assessment using a combination of dietary history, 24 h recall and food frequency. At 7 years, 125 children remained in the study. RESULTS: Mean (SD) birthweight was 3.3 (0.38) kg for boys and 3.1 (0.38) kg for girls. Mean (SD) weight at 7 years was 22.4 (4.2) kg for boys and 21.1 (3.7) kg for girls, and mean (SD) height was 120.3 (4.8) cm for boys and 119.8 (5.1) cm for girls. Hong Kong children were lighter and shorter than Australian children and the National Centre for Health Statistics (NCHS) references, but the magnitude is less than one standard deviation score. Mean weight and height of Hong Kong children were lower compared to Caucasian and Beijing children, with more obvious differences between 1 and 5 years. At 1 year, mean (SD) daily energy intake was 98 (24) kcal/kg/day for boys and 100 (26) kcal/kg/day for girls. By 7 years, it decreased to 82 (18) kcal/kg/day for boys and 73 (22) kcal/kg/day for girls. Between 2 to 4 years of age the energy intake of studied children were slightly lower than the Australian and Finnish children, but the protein intake was higher. Percentage of fat contributing to total daily energy intake was lower throughout at a level of 30%. Such differences in diet reflect a lower consumption of milk fat, higher consumption of meat and lower level of physical activity in Hong Kong children. Intakes of calcium, iron and vitamin C all reached 60% or above of US recommended daily allowance. CONCLUSIONS: The smaller body build of Chinese compared to Caucasians cannot be explained by dietary differences. The diet of Hong Kong children is changing to one which is more Westernized with a higher consumption of animal products.

Anthropometry↗
PubMed2000

Fat intake in Hong Kong Chinese children.

The people of Hong Kong are experiencing a transition in dietary practices and lifestyle that can be observed in the fat intakes of Hong Kong children as compared with those of their counterparts on mainland China. The studies described here include 1) a longitudinal and observational dietary survey beginning with a cohort of 174 newborns and concluding with 124 children at age 7 y; 2) a biochemical study of serum lipids in relation to dietary fat intake at age 7 y; 3) a chemical fatty acid analysis and comparison of duplicate meals collected from 20 Hong Kong and 20 mainland Chinese children at age 7 y; 4) a dietary assessment of 52 lactoovovegetarian children aged 4-14 y; and 5) a comparison of the growth of all subjects with US National Center for Health Statistics standards. About 30% of the total daily energy intake of Hong Kong Chinese children aged 1-7 y was contributed by fat-much more than that in the traditional Chinese diet. Growth of the children was not impaired, including that of children on the mainland and of those lactoovovegetarians in Hong Kong whose fat intakes were lower. Mean serum cholesterol of Hong Kong Chinese children at age 7 y was 4.59 mmol/L, significantly higher than that of their counterparts on the mainland, 4.16 mmol/L. Foods consumed in Hong Kong had a significantly lower ratio of 18:2 to 14:0. Nutritional deficiency was uncommon. Chinese children in Hong Kong had a dietary fat intake that was both quantitatively and qualitatively different from the traditional Chinese diet.

Adolescent↗
PubMed1999

Axial and peripheral bone mineral acquisition: a 3-year longitudinal study in Chinese adolescents.

UNLABELLED: We performed a 3-year longitudinal study of a group of 179 healthy Chinese adolescents (92 boys and 87 girls) aged from 12 to 16 years to determine the effects of puberty, physical activity, physical fitness, and calcium intake on the acquisition of bone mass. At yearly intervals for 3 consecutive years we recorded nutrition, calcium intake and anthropometric measurements, and assessed pubertal status according to Tanner. Bone mass of the lumbar spine was determined by dual-energy X-ray absorptiometry and radial bone mass by single-photon absorptiometry. Physical fitness and level of physical activity were assessed and muscle strength and power determined by isokinetic testing. Peripheral bone mass correlated with axial skeleton bone mass. Age, pubertal staging, physical fitness and muscle strength were significantly associated with bone mass increments on cross-sectional univariate and regression analysis. Longitudinal regression analysis showed that the most important factor affecting bone mass accretion in adolescents in both sexes was their pubertal stage. In boys, bone mass increment throughout the study was greater in children who were already in the advanced pubertal stages on entering the study than in those who started puberty in year 2 or 3 of the study. The percentage change in bone mineral content of the forearm and in bone mineral density of the lumbar spine was greater than 25% in the advanced pubertal group as compared to around 20% in the less mature group. For girls, the reverse was true. The increment of bone mass during the study period was significantly greater in those who presented in the earlier pubertal stages than in those who were at the more advanced stage of puberty on entry into the study. There was no significant effect of calcium intake and physical activities on the bone mass accretion. CONCLUSION: In Chinese adolescents, bone mineral accretion at adolescence is not influenced by exercise, level of physical fitness and calcium intake. In both sexes, and especially in girls, to optimally increase bone mass, regular physical exercise programmes should be instituted well before the onset of puberty rather than at or after it. Once puberty starts, these interventions may have no or only limited effect.

Adolescent↗
PubMed1999

Decreased cerebrospinal fluid absorption during abdominal insufflation.

BACKGROUND: Intracranial pressure (ICP) is known to rise during induced CO(2) pneumoperitoneum. This rise correlates with an increase in inferior vena caval pressure; therefore, it is probably associated with increased pressure in the lumbar venous plexus. Branches of this plexus communicate with arachnoid villi in the lumbar cistern and the dural sleeves of spinal nerve roots-areas where cerebrospinal fluid (CSF) absorption to normally takes place. The increased venous pressure in this area may impede CSF absorption. Because CSF is produced at a constant rate, decreased absorption will increase ICP. We hypothesized that increased ICP occurring during abdominal insufflation is due, at least in part, to decreased absorption of CSF. The purpose of this study is to show that CSF absorption is inhibited during abdominal insufflation. METHODS: After appropriate approval was obtained, 16 domestic swine were anesthetized and injected into the CSF with 100 microcuries (microCu) of I(131) radioactive iodinated human serum albumin (RISA) in 2 ml of normal saline. Eight subjects underwent CO(2) abdominal insufflation to 15 mmHg and were maintained for 4 h. A control group did not undergo insufflation. Blood levels of RISA were measured over a 4-h period to determine the rate of CSF absorption. RESULTS: Blood levels of RISA increased at a slower rate in the subjects undergoing abdominal insufflation than in the control group. The mean change over 2 h in the insufflated group was 15% compared to 34% in the control group (p = 0.02). This difference indicates decreased absorption of CSF in the insufflated group. CONCLUSIONS: These results demonstrate decreased absorption of CSF during abdominal insufflation and support the hypothesis that the increase in ICP pressure occurring during abdominal insufflation is caused, at least in part, by decreased absorption of CSF in the region of the lumbar cistern and the dural sleeves of spinal nerve roots.

Animals↗
PubMed1999

3-D power Doppler cerebral angiography in neonates and young infants: comparison with 2-D power Doppler angiography.

The aims of this study were to evaluate the ability of 3-dimensional (3-D) power Doppler angiography (3DPDA) to depict the intracranial vasculature in infants, to compare with 2-D power Doppler ultrasonography (2DPDU), and to explore the potential clinical applications of this procedure in young infants with brain disorders. We performed 3DPDA in 27 infants. 2DPDU were completed in both sagittal and coronal directions in 12 of these patients. In the other 15, only right sagittal plane images were available for comparison. Using a grading system and with only vessels with more than half of the length demonstrated included for comparison, we compared the Doppler signals of major vessels. 3DPDA could have good visualization in more than 60% of the internal carotid artery, ophthalmic artery, pericallosal artery, callosomarginal artery, internal cerebral vein, vein of Galen, and straight sinus in the sagittal plane. 3DPDA also could have good demonstration in about 50% of basilar artery in coronal plane, and posterior communicating artery, posterior cerebral artery, and lenticulostriate artery in sagittal plane. 3DPDA was better than 2DPDU in demonstrating all the major intracranial vessels in different planes, except the anterior communicating artery. In the anterior communicating artery, neither can demonstrate more than 30%.

Brain Diseases↗
PubMed1999

Vocal cord paralysis and hypoventilation in a patient with suspected Leigh disease.

The authors report the case of a 16-month-old male with suspected Leigh disease, which was diagnosed on the basis of the clinical manifestations, abnormal lactate stimulation test, proton magnetic resonance spectroscopy, and neuroradiologic findings. Progressive stridor resulting from bilateral vocal cord paralysis and hypoventilation was evident. The authors suggest that for infants or children who exhibit vocal cord paralysis, mitochondrial disorders, such as Leigh disease, should be considered.

Humans↗
PubMed1999

Power Doppler ultrasound imaging in neonatal cerebral venous sinus thrombosis.

Neonatal sinus thrombosis is a rare occurrence in sick neonates. Because of its nonspecific manifestations, the incidence is underestimated. This disease may not be demonstrated by conventional color Doppler and is diagnosed by computed tomography or magnetic resonance imaging. The authors report a neonate with neonatal sinus thrombosis diagnosed by power Doppler and suggest that the technique may be used as a less expensive and more available screening and follow-up method in high-risk neonates.

Female↗
PubMed1999

T cells contribute to disease severity during coxsackievirus B4 infection.

By using a model of coxsackievirus B4-induced disease, the question of whether tissue damage is due to the virus or to immune-mediated mechanisms was addressed. Both viral replication and T-cell function were implicated in contributing to the severity of disease. Three stages (I to III) of disease, which correspond to periods of high viral titers, low viral titers, and no infectious virus, have been identified. Stage I disease is considered to be primarily the result of viral replication. Immunopathological mechanisms appear to contribute to the severity of stage II and III disease. To investigate the role of T cells in contributing to the severity of disease, viral infection in CD8 knockout (ko) mice and CD4 ko mice was analyzed. CD8 T-cell responses appear to be beneficial during early, viral disease but detrimental in later disease when viral titers are diminishing. CD4 ko mice, unlike the parental strain, survived infection. Viral replication was lower in the CD4 ko mice. Was survival due to decreased viral replication or to the lack of T-helper-cell function? To investigate further the role of T helper cells in contributing to tissue damage, viral infection in two additional ko strains (interleukin-4 [IL-4] ko and gamma interferon ko strains) was examined. A clear correlation between viral replication and the outcome of infection was not observed. The absence of IL-4, which may influence T-helper-cell subset development, was advantageous during early viral disease but deleterious in later disease. The results suggest that T-cell-mediated immunity is both beneficial and detrimental during coxsackievirus B4 infection.

Animals↗
PubMed1998

Self-restricted dual receptor memory T cells.

Enhanced immune responses during secondary exposure to Ag result from the development of memory cells. In the present report we show that stimulation through one receptor on dual receptor CD4 cells can promote the generation of T cells capable of giving a memory response through the second receptor, even though the cells had not been previously exposed to the Ag recognized by the second receptor. Cloned cells generated from dual receptor memory T cells proliferated and secreted the same lymphokines after stimulation with either Ag. Independent recognition of both Ags by distinct TCRs was shown by production of variants that had lost either Ag specificity along with the corresponding TCR. Recognition of both Ags is MHC restricted, since the cells recognize Ag presented by self, but not non-self, MHC class II molecules. These results raise the possibility that one potential mechanism of maintaining specific memory to a given Ag is through stimulation by an unrelated Ag via the second TCR.

Animals↗
PubMed1998

Visualizing memory phenotype development after in vitro stimulation of CD4(+) T cells.

Stimulation of naive CD4 cells by specific antigen results in proliferation and changes in cell surface marker expression as the cells differentiate into effector and memory cells. Several of the marker changes (e.g., differences in CD45RB, CD44, and L-selectin levels) appear to be relatively stable and permit the identification of memory T cells. In this study, we examined the acquisition of memory markers after the initial stimulation of naive T cells. CD4(+) T cells from DO11.10 TCR transgenic mice were labeled with the fluorescent dye carboxyfluorescein diacetate succinimidyl ester (CFSE) and were stimulated with specific antigen (OVA323-339). Specific activation was observed, as CFSE-associated fluorescence was reduced twofold with each division of DO11.10 clonotype-bearing cells. Phenotypic changes could also be observed as the cells differentiated into effector/memory cells. However, individual surface markers exhibited a varied relationship to cell division. Although changes in some markers (L-selectin) occurred independently of cell division, changes in other markers were either strictly related to cell division (CD45RB) or were a prerequisite to cell division (CD4, CD44).

Animals↗
PubMed1998

Genetic immunization of chimpanzees chronically infected with the hepatitis B virus, using a recombinant retroviral vector encoding the hepatitis B virus core antigen.

Cytotoxic T lymphocyte (CTL) activity and CD4+ helper T cell responses to the hepatitis B virus (HBV) core antigen (HBcAg) have been implicated in clearance of acute and chronic HBV infections. We showed that intramuscular injections of a novel recombinant retroviral vector expressing an HBcAg-neomycin phosphotransferase II (HBc-NEO) fusion protein induces HBc/eAg-specific antibodies and CD4+ and CD8+ T cell responses in mice and rhesus monkeys. We have now immunized three chronically infected chimpanzees, each with 10(10) CFU of nonreplicating retroviral vector particles expressing the HBc-NEO fusion protein. Of two immunized chimpanzees examined for CTL responses, one developed HBcAg-specific CTLs and showed marginal, transient elevations of alanine aminotransferase (ALT) levels following injection. However, both chimpanzees remained positive for serum HBeAg, negative for anti-HBe antibody by conventional assays, and displayed no change in HBV viral load throughout the study. In contrast, the third chimpanzee exhibited a traditional seroconversion evidenced by a loss of serum HBeAg and the subsequent emergence of anti-HBe antibodies within 24 weeks after the first injection. Simultaneously, two transient ALT flares and a significant decrease in the serum HBV DNA levels were noted. Despite its limitations, the present study demonstrates (1) the safety of treatment with high titers of retroviral vector in chimpanzees, (2) the capability of a retroviral vector expressing HBcAg to stimulate immune responses in HBV chronic carrier chimpanzees, and (3) that retroviral vector immunization may be therapeutically beneficial in the treatment of chronic HBV infection.

Amino Acid Sequence↗
PubMed1998

Differential effects of lead and cAMP on development and activities of Th1- and Th2-lymphocytes.

Lead (Pb) is known to have detrimental effects on the central nervous, hematopoietic, renal, and immune systems. Herein, it is demonstrated that Pb can skew T cell reactivities by preferentially enhancing the development of Th2 cells and inhibiting the development of Th1 cells. When naive splenic CD4+ T cells from DO11.10 ovalbumin-specific transgenic (OVA-tg) mice or OVA-tg/RAG2-/- mice were developed in vitro in the presence of Pb, preferential skewing toward Th2 cells was evident. The Pb-driven skewing toward Th2 was blocked significantly in the presence of exogenous IL-12 or anti-IL-4 mAbs. Although Pb and dibutyryl cAMP (dbcAMP) appear to have similar effects on the development and reactivity of Th1 cells, unlike Pb, dbcAMP did not enhance Th2 development/activity. Further evidence of Pb's differential T cell effects was observed, in that regardless of the activation stimuli (Ag/APC; anti-CD3; PMA + ionomycin), the addition of PbCl2 consistently resulted in significant inhibition of IFN gamma production by a Th1 clone and in increased IL-4 production by a Th2 clone. In vitro addition of IL-12 overcame Pb's inhibition of Th1 cells. Th1 cells treated with a phosphodiesterase inhibitor had significantly elevated [cAMP]i levels following anti-CD3 activation in the presence of Pb, suggesting that Pb may inhibit Th1 development by enhancing adenylate cyclase activity and elevating the [cAMP]i level. Similar to Pb, a low concentration (10 microM) of dbcAMP inhibited IFN gamma production by Th1, which was prevented by IL-12; however, inhibition of protein kinase A activity by KT5720 did not reverse these effects. These results indicate that the environmental toxicant Pb can modify immune reactivities by significantly altering the differentiation of precursor or naive Th cells as well as by directly inhibiting Th1 cells and stimulating Th2 cells.

Animals↗
PubMed1998

Repair of ruptured sinus of valsalva aneurysm: determinants of long-term survival.

BACKGROUND: Ruptured sinus of Valsalva aneurysm is a rare cardiac anomaly and long-term survival after surgical treatment is not well established. This study was designed to investigate the determinants of long-term survival after repair of ruptured sinus of Valsalva aneurysm. METHODS: From April 1978 to April 1996, 53 patients underwent operation for ruptured sinus of Valsalva aneurysm. The incidence among our cardiac surgical population was 0.56%. Long-term survival was investigated in 46 patients (13 to 65 years) who survived the operation, with 96.2% follow-up completeness (mean+/-standard deviation, 6.5+/-4.9 years; maximum, 17.2 years), by univariate and multivariate analyses. RESULTS: There was no early operative death and no recurrence after the initial repair. Actuarial survival was 83.8%+/-8.4% at 15 years. Reoperation, aneurysm draining into the left ventricle, aortic prosthetic dehiscence, bacterial endocarditis, and aortic cross-clamp time (<70 minutes) were significant factors in long-term survival (p < 0.05). Multivariate analysis revealed that only aortic prosthesis dehiscence was the significant factor influencing late survival (p = 0.0001). CONCLUSIONS: Surgical treatment for ruptured sinus of Valsalva aneurysm is safe and has satisfactory results. Aortic prosthesis dehiscence is the independent determinant for long-term survival. Other factors including bacterial endocarditis, concomitant ventricular septal defect repair, and aortic valve replacement did not independently influence long-term survival.

Adolescent↗