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Biomedical subjects

M M Lee

Publications and source records attributed to M M Lee.

At least 91 records · Page 5Linked to original sources
PubMed1994

Comparison of dietary habits, physical activity and body size among Chinese in North America and China.

BACKGROUND: Chinese in North America have higher rates of many chronic diseases than do Chinese in Asia. However, there is a lack of data among comparisons of the environmental and lifestyle factors for Chinese in China and Chinese residing in North America. METHODS: We examined self-reported dietary nutrient intakes, physical activity patterns and body mass index of 2488 healthy Chinese men and women residing in North America (US and Canada) and in the People's Republic of China. RESULTS: On average, Chinese in China consumed more calories (males 2904 kcal in China, versus 2201 kcal in North America; females 2317 Kcal in China, versus 1795 Kcal in North America and more carbohydrate, but less fat (males 72.2 g in China versus 84.5 g in North America, females 56.6 g in China versus 70.8 g in North America), protein, vitamin A, beta-carotene and vitamin C than did Chinese in North America. Per cent calories from fat was 35% for Chinese in North America and 22% for Chinese in China. In contrast, the per cent of calories from carbohydrates was 62-68% in China and 48% in North America. Chinese in China reported spending more time in vigorous activity, sleeping and walking but less hours in sitting than Chinese in North America. Chinese in China weighted less and were leaner than North American Chinese. CONCLUSIONS: These differences in nutrient intakes, physical activity and body size of Chinese living on two different continents suggest possible explanations for observed differences in chronic disease rates in the two populations.

Asian People↗
PubMed1994

Relationship of gingival calculus and bleeding on probing in CPITN code 2 sextants.

The aims of this study were twofold: firstly, to evaluate the relationship of supra- or subgingival calculus and bleeding on probing (BOP) in sextants coded 2 in the Community Periodontal Index of Treatment Needs (CPITN); and secondly, to compare the differences in four investigations in Taiwan, Hong Kong, Japan and Norway. In a national survey, a total of 2658 Chinese dentate adults were examined by using modified CPITN in the Taiwan area from 1985 to 1987. Sextants given Code 2 were divided into four subclassifications: supragingival calculus with bleeding (I+), supragingival calculus without bleeding (I-), subgingival calculus with bleeding (II+) and subgingival calculus without bleeding (II-). The results showed that of the 9394 sextants given Code 2, the highest percentage (70%) were characterized by the presence of subgingival calculus with bleeding and the lowest percentage (4%) by supragingival calculus with bleeding. The ratio of sextants coded 2 with only supragingival calculus versus subgingival was 1:6.2. The bleeding to nonbleeding ratio of sextants coded 2 in this study was similar to the Hong Kong study. However, differences among Taiwan, Japan and Norway were found. The results indicated that sextants with subgingival calculus had a higher tendency to BOP, with a ratio of 4:1. Those with supragingival calculus had a ratio of 3:7. We conclude therefore, that it is essential to scale teeth to remove subgingival calculus for determination of the necessity of periodontal treatment.

Adolescent↗
PubMed1994

Developmental changes in mullerian inhibiting substance in the cynomolgus monkey, Macaca fascicularis.

Mullerian inhibiting substance (MIS) is a glycoprotein hormone produced in Sertoli cells of the fetal and postnatal testis, and granulosa cells of the pubertal ovary. We examined MIS expression in a nonhuman primate, the cynomolgus macaque monkey (Macaca fascicularis), to define an animal model for studying MIS gene regulation. Changes in testicular MIS mRNA with age were assessed by in situ hybridization of prepubertal to adult testes, Northern analysis of pubertal and adult specimens, and determination of serum MIS concentrations from infancy to adulthood. We found that MIS expression was highest in the youngest animals and decreased progressively with increasing age. Serum MIS concentrations correlated inversely with increasing age (r = -0.74), body weight (r = -0.79), and testicular volume (r = -0.73), but not with testosterone levels (r = -0.35). The mean MIS concentrations +/- SEM for the four developmental age groups were 270.6 +/- 23.8 (infants), 195.5 +/- 18.5 (juveniles), 102.7 +/- 28.4 (peripubertals), and 51.6 +/- 7.1 (adults). This study confirms that nonhuman primate and human MIS are highly homologous and have similar developmental patterns. The normative data for serum MIS concentrations in cynomolgus monkeys at different ages and developmental stages will be invaluable for further work examining MIS regulation.

Aging↗
PubMed1994

Variant angina complicating ergot therapy of migraine.

A 55-year-old man demonstrated typical reflux esophagitis, not esophageal spasm, by esophageal manometry, although he demonstrated classic migraine, positive Raynaud's scan, and proven coronary artery spasm. He suffered from severe chest pain by medication of ergotamine tartrate. Ergot alkaloids should be avoided in patients with symptomatic coronary artery spasm.

Angina Pectoris, Variant↗
PubMed1994

The role of sunlight and DNA repair in melanoma and nonmelanoma skin cancer. The xeroderma pigmentosum paradigm.

BACKGROUND AND DESIGN: The frequency of melanoma and nonmelanoma skin cancer is increasing rapidly in the United States. However, the linkage of these cancers to sun exposure has been questioned because of differences in anatomic site distribution. To obtain insights into the development of these skin cancers, we examined reports of 132 patients with xeroderma pigmentosum (XP), an inherited cancer-prone, DNA repair-deficient disorder with marked clinical and laboratory UV hypersensitivity. RESULTS: Malignant skin neoplasms were present in 70% of the patients with XP at a median age of 8 years, which is 50 years earlier than in the US white population. Fifty-seven percent of the patients had basal cell or squamous cell carcinoma, and 22% had melanoma. The frequency of melanomas, like the frequency of nonmelanoma skin cancers (basal cell and squamous cell carcinomas), anterior eye cancers, and tongue cancers, but unlike that of internal neoplasms, was increased 1000-fold or more in patients with XP who were younger than 20 years. As in the general population, the anatomic distribution of melanomas was different from that of nonmelanomas in the patients with XP. CONCLUSIONS: These data suggest that (1) DNA repair plays a major role in the prevention of cutaneous cancers in the general population and (2) sunlight exposure is responsible for the induction of melanoma as well as nonmelanoma skin cancer in patients with XP, although acting by different mechanisms for the two types of skin cancer.

Adolescent↗
PubMed1993

A human DNA segment encompassing leucine and methionine tRNA pseudogenes localized on chromosome 6.

A human genomic clone, designated LHtlm8, that strongly hybridized to a mammalian leucine tRNA(IAG) probe, was found to encompass a pair of tRNA pseudogenes that are transcribed in a homologous cell extract. A leucine tRNA(AAG) pseudogene (TRLP1) is 2.1-kb upstream and of opposite polarity to a methionine elongator tRNA(CAU) pseudogene (TRMEP1). TRLP1 has three nucleotide variations (97% identity) from its cognate leucine tRNA(IAG), while TRMEP1 has a 78% identity with its cognate tRNA. Similar to a number of other eukaryotic tRNA pseudogenes, presumptive precursor tRNA transcripts are generated from the two pseudogenes in vitro, but possibly due to their aberrant and unstable secondary and tertiary structures, no detectable mature tRNA products are observed. The two tRNA pseudogenes are encompassed within a 9.6-kb EcoRI fragment that has been assigned to the chromosomal locus, 6pter-q13, by Southern blot hybridization of human-rodent somatic cell hybrid DNAs with probes derived from the cloned tRNA pseudogenes and flanking sequences. A 4.4-kb EcoRI fragment also harbored in clone LHtlm8 was mapped to human chromosome 11, suggesting that the two EcoRI fragments were inadvertantly ligated together during construction of the genomic library.

Animals↗
PubMed1993

A study of surface property changes in rat mesothelial cells induced by asbestos using aqueous two-phase polymer solutions.

Intraperitoneal (i.p.) injection of crocidolite asbestos was used to induce mesotheliomas in rats. The morphological changes of the mesothelial cells were studied by light and electron microscopy and by cytologic examination of peritoneal washings. After injection, the asbestos fibres stimulated an acute inflammatory response and were rapidly phagocytosed by the mesothelial cells and incorporated into the submesothelial tissues. At 7 days, the normal microvillous surface of the mesothelium was replaced with a syncytium of proliferating mesothelial cells showing extensive loss of microvilli. Nine months or so later, multifocal mesothelial tumours arose within the peritoneal cavity. The surface thermodynamic properties of normal, asbestos-stimulated mesothelial cells and of mesothelial tumour cells in culture were studied using an aqueous two-phase system containing 4% Dextran T-2000 and 4% poly (ethylene glycol) (PEG) w/w. After asbestos stimulation, there was a significant (P < 0.01) increase in contact angle between the dextran-rich phase and the mesothelial cell surface. These changes were even greater for the mesothelial tumours. The results indicate that the work of adhesion for asbestos-stimulated mesothelial cells and mesothelial tumours is lower than in normal tissue. These findings may be relevant to the process of tumour spread in the serosal cavities and to the development of distant metastases.

Animals↗
PubMed1993

Breast cancer risk associated with abnormal cytology in nipple aspirates of breast fluid and prior history of breast biopsy.

The authors previously reported an increased risk of breast cancer in women from the San Francisco Bay Area first enrolled between 1973 and 1980 with proliferative cytologic findings (hyperplasia, moderate hyperplasia, and atypia) compared with women with normal cytologic findings in breast fluids obtained by nipple aspiration and with women from whom breast fluid could not be obtained. To look for factors which might modify the risks associated with cytology, the authors examined several standard breast cancer risk factors: parity, age at first pregnancy, age at menarche, family history of breast cancer, and prior history of breast biopsy. Among women aged 30 years or over, only prior biopsy modified the effect of proliferative cytologic findings on the risk of breast cancer (p < 0.10). For those women with no prior biopsy, breast cancer incidence was 5% (47 of 985) among women with normal cytology and 5% (13 of 277) among women with proliferative findings, whereas among those women with normal cytology and 18% (11 of 62) among women with proliferative cytology. Age-adjusted as well as multivariate-adjusted relative risks indicated that the increased risk of breast cancer associated with proliferative cytologic findings was largely confined to women who had a prior history of breast biopsy.

Adult↗
PubMed1993

Type I glycogen storage disease: nine years of management with cornstarch.

Long-term effects of cornstarch (CS) therapy on biochemical values and physical growth in children with type I glycogen storage disease (GSD I) were compared to those of children receiving continuous nocturnal nasogastric glucose feedings (CNG). Only patients who had received more than 5 years of dietary therapy (either CS or CNG) were evaluated. Six patients (five female, age 13.5 years +/- 1.3, range 11.7-16.5 years) received CS (1.75-2.5 g/kg, four times daily) and seven patients (five female, age 9.6 +/- 2.5 years, range 7.3-14.8 years) received CNG. Blood glucose, lactate, cholesterol and triglyceride levels were not significantly different between the two methods of treatment. All patients maintained linear growth rates normal for their age. The standard deviation score of height after 6.7 +/- 1.6 years (range 5-9 years) of CS treatment was -1.29 +/- 0.59 and after 8.8 +/- 2.4 years (range 7-14 years) of CNG was -1.24 +/- 0.63. These values did not differ significantly from each other or from the target height, an estimate of genetic potential for height as determined from parental heights. With the exceptions of diarrhea, increased flatulence and excess weight gain, there were no adverse effects of CS after 9 years of treatment. Our data suggests that cornstarch is a simple, effective and safe therapy for GSD I.

Adolescent↗
PubMed1993

Relation of pulmonary venous flow to mean left atrial pressure in mitral stenosis with sinus rhythm.

To determine whether pulmonary venous flow measured by transesophageal Doppler echocardiography can be used to estimate mean left atrial pressure (LAP), we prospectively studied 12 consecutive patients with sinus rhythm undergoing percutaneous mitral balloon commissurotomy for their severe mitral stenosis (mitral valve area < 1.5 cm2). We correlated Doppler variables of pulmonary venous flow and the mean LAP measured by left atrial catheterization. Among the variables of the pulmonary venous flow, the systolic fraction (i.e., the systolic velocity-time integral expressed as a fraction of the sum of systolic and early diastolic velocity-time integral) correlated significantly with mean LAP (r = -0.71, p < 0.05) and mitral valve area (r = 0.64, p < 0.05). Peak velocity and velocity-time integral in systole also significantly correlated with mean LAP (r = -0.66, r = -0.67 respectively, p < 0.05). We conclude that the more severe the degree of mitral stenosis in patients with sinus rhythm, the less systolic pulmonary venous flow in severe mitral stenosis.

Adult↗
PubMed1993

Müllerian inhibiting substance in the diagnosis and management of intersex and gonadal abnormalities.

Müllerian inhibiting substance (MIS), a gonadal hormone important in sexual differentiation, is high (10 to 70 ng/mL) in human male serum postnatally for several years before declining during the peripubertal period, but is undetectable in female serum until the onset of puberty. The sexually dimorphic secretion of MIS suggested possibilities for its use in several clinical settings. Thirty-one patients with intersex and gonadal anomalies from 17 institutions were therefore evaluated between 1989 and 1992 with an MIS enzyme-linked immunosorbent assay (ELISA). Serum MIS levels correlated with the presence of testicular tissue in two patients with suspected anorchia, five patients with male pseudohermaphroditism, and eight other intersex patients with undescended testes, dysgenetic gonads, or ovotestes. In these latter patients, serial MIS values were also helpful to confirm complete removal of gonadal tissue postoperatively. MIS may be a more sensitive marker for the presence of testicular tissue than serum testosterone levels, both before and after the neonatal androgen surge, and, consequently, may obviate the need for human chorionic gonadotropin stimulation in the evaluation of certain intersex disorders. In values were useful in differentiating the underlying etiology of the disorder. Four patients with undetectable levels have presumptive MIS gene mutations, while 7 others with MIS values of 2 to 45 ng/mL may have bioinactive hormone of MIS receptor defects. Finally, two young girls with ovarian granulosa cell tumors had elevated MIS values that fell from 18 to 2 ng/mL and from 6.5 to 1 ng/mL during postoperative follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

The reappraisal of the association of glycosylated hemoglobin A1c (HbA1c) and blood pressure: a hypertension and diabetes study in a Taiwan rural area.

The association of age, body weight, body mass index (BMI) and glycosylated hemoglobin A1c (HbA1c) to blood pressure in the general population of the Ho-long area in Taiwan was examined. A total of 1341 subjects, 746 men and 595 women, aged 40-90 years, were studied. Sex-specific multiple regression analyses were carried out on variables both univariately and significantly associated with blood pressure. Results show HbA1c to be significantly associated with SBP in both males and females before age, weight and/or BMI are adjusted (p < 0.05). After controlling for these confounders, the strength of SBP-HbA1c association was slightly reduced in males, but remained significant. In contrast, there was no significance in females. Moreover, no significant relationship in DBP-HbA1c was found in either sex group. These findings suggest that although a positive correlation was found between HbA1c and SBP, HbA1c or glucose status appeared to be a less important contributing factor in hypertension than age or body weight.

Age Factors↗
PubMed1993

Müllerian inhibiting substance is present in embryonic testes of dogs with persistent müllerian duct syndrome.

Müllerian Inhibiting Substance (MIS) causes regression of the Müllerian ducts during a critical period in embryonic development in male mammals. In Persistent Müllerian Duct Syndrome (PMDS), an autosomal recessive trait in humans and dogs, the Müllerian ducts fail to regress in otherwise normal males. Previously we reported that PMDS-affected dogs produce bioactive testicular MIS postnatally. The purpose of the present study was to determine whether PMDS-affected canine embryos appropriately express MIS mRNA and protein during the critical period for Müllerian duct regression. Homozygous (PMDS-affected) and normal canine embryos were removed from timed pregnancies. Gonadal sex and the degree of Müllerian duct regression were determined from histologic sections. Positive immunohistochemical staining for MIS was found in testis sections of PMDS-affected and normal male embryos. A 1.8-kb MIS mRNA transcript was detected in testes of PMDS-affected males and normal male embryos and neonates. Furthermore, equal amounts of MIS mRNA transcript were detected in testes of PMDS-affected embryos and normal male littermates during the critical period for Müllerian duct regression. These data support a hypothesis of target organ resistance, such as an abnormality in the putative MIS receptor, as the etiology of the defect in this dog model.

Animals↗
PubMed1993

Mullerian inhibiting substance: a gonadal hormone with multiple functions.

Mullerian inhibiting substance (MIS) is the gonadal hormone that causes regression of the Mullerian ducts, the anlagen of the female internal reproductive structures, during male embryogenesis. MIS is a member of the large transforming growth factor-beta (TGF beta) multigene family of glycoproteins that are involved in the regulation of growth and differentiation. The proteins in this gene family are all produced as dimeric precursors and undergo posttranslational processing for activation, requiring cleavage and dissociation to release bioactive C-terminal fragments. Similarly, the 140 kilodalton (kDa) disulfide-linked homodimer of MIS is proteolytically cleaved to generate its active C-terminal fragments. The sexually dimorphic expression of MIS in Sertoli cells of the testis and granulosa cells of the ovary is critical for normal differentiation of the internal reproductive tract structures. A number of extra-Mullerian functions such as control of germ cell maturation and gonadal morphogenesis, induction of the abdominal phase of testicular descent, suppression of lung maturation, and growth inhibition of transformed cells have also been proposed for this growth-inhibitory hormone and will be discussed. This article will summarize the current understanding of the biology and multiple functions of MIS including its activation, regulation, and mechanism of action and discuss areas of interest in ongoing research.

Adolescent↗
PubMed1992

Breast cancer incidence in women with abnormal cytology in nipple aspirates of breast fluid.

This is a prospective study of breast cancer risk in relation to nipple aspirate fluid cytology in 2,701 volunteer white women from the San Francisco Bay Area first enrolled between 1973 and 1980. The women were not pregnant or lactating and were free of breast cancer within 6 months of entry into the study. The breast cancer status of this cohort was determined between June 1988 and April 1991. Follow-up was complete for 87% (n = 2,343) of the cohort, representing 29,961 person-years and an average of 12.7 years of follow-up. The overall breast cancer incidence was 4.4% (104 of 2,343) and rose with fluid cytology findings as follows: no fluid obtained, 2.6% (9 of 352); unsatisfactory specimen, 4.8% (15 of 315); normal cytology, 4.3% (56 of 1,291); epithelial hyperplasia, 5.5% (18 of 327); and atypical hyperplasia, 10.3% (6 of 58). Relative risks for breast cancer and their 95% confidence intervals were estimated by Cox regression, adjusting for age and year of entry. Compared with the relative risk for women who yielded no fluid, relative risks were: unsatisfactory specimen, relative risk (RR) = 1.4 (95% confidence interval (CI) 0.6-3.3); normal cytology, RR = 1.8 (95% CI 0.9-3.6); epithelial hyperplasia, RR = 2.5 (95% CI 1.1-5.5); and atypical hyperplasia, RR = 4.9 (95% CI 1.7-13.9). These findings were strongest for and were mainly confined to women aged 25-54 years. Women with atypical hyperplasia and a first-degree family history of breast cancer were six times more likely to develop breast cancer than were women with atypical hyperplasia but without a family history of breast cancer (95% CI 1.0-30.2). These findings provide strong support for our hypothesis that hyperplasia and atypical hyperplasia diagnosed in nipple aspirates of breast fluid are associated with an increased risk of breast cancer.

Adolescent↗