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Biomedical subjects

M M Lee

Publications and source records attributed to M M Lee.

At least 109 records · Page 6Linked to original sources
PubMed1992

Takayasu arteritis in Korea: clinical and angiographic features.

Clinical and angiographic features of Takayasu arteritis were investigated in 129 Korean patients. This disease affects females more frequently than males, in a ratio of 6.6 to 1. Of the total number of patients, 51 were in the third decade, 27 in the fourth decade, and 23 in the second decade. Common clinical symptoms were headache (60%), exertional dyspnea (42%), dizziness (36%), and malaise or weakness (34%). Takayasu arteritis affected the abdominal aorta (46%) and descending thoracic aorta (37%) more frequently than the ascending aorta (1%) and aortic arch (2%) According to Ueno's classification based on aortographic findings, the 129 patients were divided into type I (37), type II (25), and type III (67). Among the 48 patients who had coronary angiography, 11 (23%) showed coronary arterial involvement. Because the clinical features are determined by the extent and severity of the specific artery involved in the occlusive phase of the disease, total aortography including coronary angiography is very important in the initial evaluation of Takayasu arteritis.

Adolescent↗
PubMed1992

Isolation of the rat gene for Mullerian inhibiting substance.

Mullerian inhibiting substance (MIS), a testicular glycoprotein also known as anti-Mullerian hormone, plays a key role in male sexual development by causing regression of the Mullerian duct, the anlagen of the uterus, the Fallopian tubes, and part of the vagina. MIS is also expressed in the postnatal ovary, but its precise function is still not known. We report here the complete nucleotide sequence of the rat MIS gene. Rat MIS is encoded in five exons and is synthesized as a precursor of 553 amino acids, containing a 24-amino-acid leader. Based on homology with human MIS, we predict that the rat protein undergoes proteolytic processing at a site 108 amino acids from the C-terminus. Expression of the rat MIS mRNA is high in the 1-day-postnatal testis and decreases to a low level in the adult testis. In contrast, expression is not detected in the 1-day ovary, but increases to an intermediate level in the adult ovary. The rat gene should provide a good model for studying transcriptional regulation of MIS in the testis and ovary.

Animals↗
PubMed1992

Reliability of recalled physical activity, cigarette smoking, and alcohol consumption.

Reliability of recalled measures of physical activity and alcohol and tobacco use was examined in a cohort of 873 men and women in three California communities. In personal interviews in 1972, participants provided baseline data on these three habits. In repeat interviews in 1983, they recalled their habits in 1972 and reported their current habits. On average, recalled physical activity levels significantly exceeded those originally reported (1899 kcal/d versus 1345 kcal/d, P < 0.001) and were similar to current reported levels (1822 kcal/d). Similarly, recalled alcohol and cigarette consumption was higher than the original reports (alcohol: 126 versus 119 g/wk; cigarettes: 8.5 versus 6.2/d). By contrast, current reported alcohol (103 g/wk) and cigarette consumption (4.6/d) were lower than at baseline. Analysis of variance was used to partition the variation in recalled and original habits into components due to interpersonal variation in true measures, errors in recall, and residual reporting error. Interpersonal variation accounted for only 20% of the total variation in physical activity, but for 48 to 60% of total variation in cigarette smoking and alcohol consumption. These results suggest that inconsistencies among studies of chronic disease and physical activity may arise from either large random measurement errors in individual assessments or from homogeneity of activity levels among the populations studied.

Adult↗
PubMed1992

Foods predictive of nutrient intake in Chinese diet in Taiwan: I. Total calories, protein, fat and fatty acids.

Dietary consumption data obtained by food weighing for 539 households in Taiwan in 1980-1981 were used to search for foods predictive of nutrient intake. The average per capita nutrient intake in each household was calculated for total calories, protein, fat and fatty acids (saturated fatty acids, oleic acid and unsaturated fatty acids). Stepwise multiple regression analysis was carried out to reveal the relative importance of each of 405 food items in the dietary survey data for predicting nutrient intake. We found that as few as seven to 20 food items could account for a large proportion of the variability of macronutrient intake in this population. These lists of foods were the minimum needed to categorize an individual's nutrient intake for epidemiological studies in Taiwan. The types and amounts of cooking oils (important predictors of fat and calories) added to the dishes were found to vary from family to family, and should be considered in designing dietary questionnaires for Chinese in other societies.

Adolescent↗
PubMed1992

Foods predictive of nutrient intake in Chinese diet in Taiwan: II. Vitamin A, vitamin B1, vitamin B2, vitamin C and calcium.

Dietary consumption data obtained by food weighing for 539 households in Taiwan in 1980-1981 were used to search for predictor foods of individual intake of several vitamins and calcium. Stepwise multiple regression analysis was carried out on food items that were univariately and significantly associated with nutrient intakes, to screen for the important predictors. Less than ten foods were enough to explain more than 90% of the interperson variation for vitamin A, vitamin B1, and vitamin B2. For vitamin C and calcium, 20 food items could explain only 87% of the variation. Salt, brown sugar, and soy bean sauce were selected among calcium predictors. The information on foods predictive of nutrient intake is useful in designing food frequency questionnaires and materials for nutrition education. Although this paper provides such information for Chinese living in Taiwan, some issues described (such as the need to assess spices) may have been overlooked and could be generalized to populations using stir-frying as a major cooking method.

Ascorbic Acid↗
PubMed1992

Developmentally regulated polyadenylation of two discrete messenger ribonucleic acids for müllerian inhibiting substance.

Mullerian inhibiting substance (MIS) is a 140-kilodalton homodimeric glycoprotein that causes regression of the Mullerian ducts in male embryos, and may also have a role in both males and females in the regulation of germ cell maturation. We examined the ontogeny of MIS messenger RNA (mRNA) in rat testes from midgestation through adulthood and found two discrete MIS mRNA species that are developmentally regulated. The larger 2.0-kilobase species is abundant at embryonic day 14, then decreases in late gestation, and is barely detectable after birth. The smaller 1.8-kilobase species is first noted at embryonic day 18 and is the major species detected postnatally. Both species are abundant just prior to birth, at embryonic day 21, then decrease markedly after birth. This variation in MIS mRNA levels correlates with the developmental expression of MIS protein. A series of oligonucleotide-directed ribonuclease H mapping experiments determined that the two mRNA species differ at their 3' ends in the extent of polyadenylation. Thus, differential polyadenylation of MIS mRNA may be an additional mechanism for regulating MIS expression during fetal and postnatal development.

Aging↗
PubMed1992

Mullerian inhibiting substance messenger ribonucleic acid expression in granulosa and Sertoli cells coincides with their mitotic activity.

In males, Mullerian inhibiting substance (MIS) mRNA was first detected on the medial aspect of the urogenital ridge early on the morning of day 13 of gestation before testicular differentiation was evident, and localized to the more obvious Sertoli cells later on embryonic day 13. MIS transcripts remained at maximal levels between 14.5 and 17.5 days gestation, while the Mullerian duct involutes, and remained high until birth. MIS gene expression decreased progressively after birth and, as germ cell meiosis increased, became barely detectable in the Sertoli cells of the seminiferous tubules. In female rats, MIS mRNA was first detected in the single layer of cuboidal granulosa cells surrounding larger primary follicles 3 days after birth, coincident with the initiation of follicular growth. As follicular growth progressed, MIS mRNA expression was high in preantral and small antral follicles, especially in those granulosa cells closest to the oocyte. MIS mRNA expression decreased gradually in larger antral follicles, remaining prominent only in the cumulus cells and the dividing population of granulosa cells closest to the lumen. MIS gene expression was absent in follicles with features of atresia and in the larger antral follicles. The expression of MIS mRNA in actively dividing Sertoli and granulosa cells correlates with the stages of germ cell division. These findings are suggestive of a role for MIS in the control of germ cell maturation.

Animals↗
PubMed1992

Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men.

Serum GH concentrations are increased in fasted or malnourished human subjects. We investigated the dynamic mechanisms underlying this phenomenon in nine normal men by analyzing serum GH concentrations measured in blood obtained at 5-min intervals over 24 h on a control (fed) day and on the second day of a fast with a multiple-parameter deconvolution method to simultaneously resolve endogenous GH secretory and clearance rates. Two days of fasting induced a 5-fold increase in the 24-h endogenous GH production rate [78 +/- 12 vs. 371 +/- 57 micrograms/Lv (Lv, liter of distribution volume) or 0.24 +/- 0.038 vs. 1.1 +/- 0.16 mg/m2 (assuming a distribution volume of 7.9% body weight), P = 0.0001]. This enhanced GH production rate was accounted for by 2-fold increases in the number of GH secretory bursts per 24 h (14 +/- 2.3 vs. 32 +/- 2.4, P = 0.0006) and the mass of GH secreted per burst (6.3 +/- 1.2 vs. 11 +/- 1.6 micrograms/Lv, P = 0.002). The latter was a result of increased secretory-event amplitudes (maximal rates of GH release attained within a burst) with unchanged secretory burst durations. GH was secreted in complex volleys composed of multiple discrete secretory bursts. These secretory volleys were separated by shorter intervals of secretory quiescence in the fasted than fed state (respectively, 88 +/- 4.2 vs. 143 +/- 14 min, P = 0.0001). Similarly, within volleys of GH release, constituent individual secretory bursts occurred more frequently during the fast [every 33 +/- 0.64 (fasted) vs. every 44 +/- 2.0 min (fed), P = 0.0001]. The t1/2 of endogenous GH was not significantly altered by fasting [18 +/- 2.2 (fasted) vs. 20 +/- 1.5 min (fed), P = 0.47]. Serum insulin-like growth factor I concentrations were unchanged after 56 h of fasting. In conclusion, the present data suggest that starvation-induced enhancement of GH secretion is mediated by an increased frequency of GHRH release, and longer and more pronounced periods of somatostatin withdrawal.

Adult↗
PubMed1992

Percutaneous mitral valvuloplasty in a mid-term pregnant woman with severe rheumatic mitral stenosis.

A 28-year-old woman with severe mitral stenosis underwent percutaneous mitral valvuloplasty at 26 weeks' gestation. Balloon dilation using a double 18-18 mm balloon resulted in improvement in mean mitral pressure gradient (32 to 8 mmHg) and in calculated mitral valve area (0.9 to 2.4 cm2) without complications and any evidence of fetal distress during procedures with an estimated radiation exposure to the fetus of 0.13 rem. This procedure resulted in the disappearance of symptoms of congestive heart failure and allowed for normal full term spontaneous delivery of a 3.51 Kg boy without any complication.

Adult↗
PubMed1991

The mechanism of differential sensitivity to methotrexate of normal and malignant human epidermal cells.

Squamous carcinoma cells are much more sensitive (greater than 10(4) times) to the cytotoxic effects of methotrexate (MTX) and 5-fluorodeoxyuridine (FUDR) than are normal human keratinocytes as measured by cell growth. Among the drugs tested, this phenomenon was found to be specific for MTX and FUDR, since arabinosylcytidine (ARA-C), 13-bis-chloroethylnitrosourea (BCNU), and daunomycin failed to show differences in inhibition between the normal and malignant cell lines. Drug uptake studies did not reveal a significant difference in MTX intracellular levels between malignant and normal epidermal cell lines at 60 min. Thymidine (TdR) salvage was assessed by examining the effects of the presence of 3 microM TdR on MTX-induced cytotoxicity. On the withdrawal of TdR, normal cells demonstrated an increased level of inhibition amounting to 4 orders of magnitude, whereas the squamous-cell carcinoma cells showed no change in sensitivity. Interestingly, the immortal nontumorigenic keratinocyte line (NM-110) was similarly not rescued by the addition of TdR. The high degree of sensitivity TO MTX shown by squamous-cell carcinoma (SCC) and NM-110 cells is attributable to a significant diminution of their ability to use exogenous TdR as compared with that of normal keratinocytes and might be indicative of a biochemical change associated with cellular immortality.

Carcinoma, Squamous Cell↗
PubMed1991

Müllerian inhibiting substance production and cleavage is modulated by gonadotropins and steroids.

Analysis of the ontogeny and localization of the amino (N)-terminal and carboxy (C)-terminal cleavage products of Müllerian Inhibiting Substance (MIS) and their modulation by hormones of the hypothalamic-pituitary gonadal axis by immunohistochemistry and Northern analysis led to the discovery of a novel mode of posttranslational regulation of this differentiating agent. Antibody to both holo- and C-terminal MIS identically stained the cytosol of testicular Sertoli cells from 21-day fetal rats, whereas staining of antibody to N-terminal MIS localized to the basement membrane of seminiferous tubules. In addition, when studied longitudinally, basement membrane staining for N-terminal MIS persisted; cytosolic staining for C-terminal MIS was no longer detectable in post-natal testes, but marked basement membrane staining for the N-terminal fragment could still be observed in the testes of untreated 7-day postnatal animals. When 19-day fetuses were injected with FSH, testes collected 2 days later showed less immunohistochemical staining for holo-, N-, and C-terminal MIS, and less MIS messenger RNA. This suggested that FSH downregulates MIS transcription, as had been shown previously in neonatal testes treated with FSH. Testes collected at 21 days from fetuses treated at day 19 in utero with human CG or testosterone, also showed less staining for holo-MIS, but, surprisingly, increased staining for the N- and C-terminal fragments. These changes in MIS protein were accompanied by no or minimal changes in MIS messenger RNA levels, indicating that human CG and testosterone do not affect transcription, but may regulate the cleavage and/or dissociation of MIS. This study describes a form of post-translational regulation of MIS and shows that both transcription and processing of MIS may be differentially modulated by gonadotropins and sex steroids.

Amino Acid Sequence↗
PubMed1991

Successful management of mechanical complications following acute myocardial infarction--a case report.

Rupture of the heart as a complication of myocardial infarction is one of the most common causes of in-hospital mortality. Rupture of the free wall of the ventricle or interventricular septum has a poor prognosis when treated conservatively. So, rupture of the heart after infarction requires prompt diagnosis and early surgical repair despite the high overall incidence of early operative mortality before hemodynamic deterioration and multiorgan failures develop. Rupture of the left ventricle results in pseudoaneurysm if the overlying pericardium adhers to the surface of the heart. Pseudoaneurysms which rarely develop after infarction, tend to rupture. Their presence alone is an indicator for operation because of the very poor prognosis following rupture. We experienced successful management of 2 rare complications after acute myocardial infarction: ventricular septal defect and pseudoaneurysm. The first patient was a 49-year-old man who had an apical septal defect. His electrocardiogram showed Q wave in leads V2-V6, II, III, and aVF but a coronary angiogram showed normal findings. He was successfully treated by patch closure of the septal defect. The second patient was a 65-year-old female who had false aneurysm of the left ventricle. She had neither chest pain nor abnormality on the electrocardiogram. A coronary angiogram showed complete occlusion of the distal circumflex artery. Under cardiopulmonary bypass, the neck of the aneurysmal sac was successfully closed with a prolene suture.

Aged↗
PubMed1991

Pulmonary calcification caused by Pneumocystis carinii pneumonia. A clinicopathological study of 13 cases in acquired immune deficiency syndrome patients.

Pulmonary microcalcifications were identified in 13 patients with Pneumocystis carinii pneumonia (PCP) and acquired immune deficiency syndrome (AIDS). Several patterns of calcification were noted including bubbly, plate-like, elongate, and conchoidal forms. All calcifications contained P. carinii cysts within them as demonstrated by Grocott's methenamine silver stain. In eight of the 13 cases, the typical intra-alveolar exudate of P. carinii was absent. Therefore, the calcifications were the only histopathologic indication of prior P. carinii infection. The above-mentioned calcifications are important because in five cases they occurred without a prior diagnosis of PCP, subsequent therapy, or prophylaxis. This indicates that in some patients there is destruction of P. carinii organisms with subsequent calcification, and this can occur without therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Adhesive interaction of erythrocytes in vitro in multiple myeloma.

The early stage of rouleaux formation, which can be observed on a microscope slide, was assessed quantitatively for pairs of cells forming adhering doublets. Previous work on normal cells in normal plasma has been extended to blood samples from patients with multiple myeloma, a blood disorder with a large component of high molecular weight immune plasma protein. Cine film records were obtained for each of 19 pairs of cells which made adhesive contact in a cell suspension diluted by myeloma blood plasma. Analysis, restricted to the events of sliding contact between cells, revealed an approximate doubling of peak sliding velocity, a marked reduction in time to half complete sliding interaction (13 compared to 56 sec for normal cells), and a high variance when comparing sliding velocity as a function of position of overlap. We invite consideration that circumstances of low or zero fluid shear rate that can occur in the venous side of the circulation might have a transient but profound affect on local blood viscosity.

Blood Flow Velocity↗