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Biomedical subjects

P A Lee

Publications and source records attributed to P A Lee.

At least 19 recordsLinked to original sources

Staggered local density of states around the vortex in underdoped cuprates.

We have studied a single vortex with the staggered flux (SF) core based on the SU(2) slave-boson theory of high T(c) superconductors. We find that, whereas the center in the vortex core is a SF state, as one moves away from the core center a correlated staggered modulation of the hopping amplitude chi and pairing amplitude Delta becomes predominant. We predict that in this region the local density of states exhibits staggered modulation when measured on the bonds, which may be directly detected by STM experiments.

Journal Article↗

Counselor and stimulus control enhancements of a stage-matched expert system intervention for smokers in a managed care setting.

BACKGROUND: Previous research has demonstrated the efficacy of an interactive expert system intervention for smoking cessation for a general population. The intervention provides individualized feedback that guides participants through the stages of change for cessation. Enhancing the expert system by adding proactive telephone counseling or a stimulus control computer designed to produce nicotine fading could produce preventive programs with greater population impacts. METHODS: Four interventions were compared: (a) the interactive expert system intervention; (b) the expert system intervention plus counselor calls; (c) the expert system intervention plus the stimulus control computer; and (d) an assessment only condition. A 4 (intervention) x 4 (occasions) (0,6,12, and 18 months) design was used. Smokers were contacted at home via telephone or mail. The initial subject pool was the 24,178 members of a managed care company. Screening was completed for 19,236 members (79.6%), of whom 4,653 were smokers; 85.3% of the smokers were enrolled. RESULTS: Thirty-eight percent were in the precontemplation stage, 45% in the contemplation stage, and only 17% in the preparation stage. At 18 months, the expert system resulted in 23.2% point prevalence abstinence, which was 33% greater than that of assessment only. The counselor enhancement produced increased cessation at 12 months but not at 18 months. The stimulus control computer produced no improvement, resulting in 20% worse cessation rates than the assessment only condition. CONCLUSIONS: The enhanced conditions failed to outperform the expert system alone. The study also demonstrated the ability of the interactive expert system to produce significantly greater cessation in a population of smokers than assessment alone.

Adult↗

Age of puberty: data from the United States of America.

In an attempt to determine whether the secular trend toward an earlier onset of puberty has continued over recent decades in the United States of America, published reports concerning the age of attainment of pubertal events have been reviewed. Such reports are very limited and vary in both design and inclusive ages of study subjects. Among females, two recent large cross-sectional studies indicate that fifty percent of females in the United States attain Tanner breast stage 2 at 9.5 to 9.7 years of age. This is younger than previously thought, although adequate earlier studies of girls in the United States are not available for comparison. These two studies also indicate that about 14% of girls attain Tanner stage 2 while 8 years of age; one study extends earlier reporting that about 6% exhibit onset of breast development while 7 years of age. There is no evidence that the age of menarche or the attainment of adult (Tanner 5) breast development has decreased over the past 30 years. The data also suggest an earlier onset of Tanner stage 2 pubic hair but no change in attainment of stage 5. Among males, pubic hair may be appearing at younger ages, but data are inadequate or too inconsistent to allow firm interpretation. The lack of standardization of genital criteria of pubertal onset in the male makes any conclusions regarding secular trends impossible. In summary, earlier secular trends over recent decades related to better health, improved nutrition or socio-economic status, or any putative influence by endocrine disrupters cannot be verified.

Adolescent↗

Relationship of young adult Chinese Americans with their parents: variation by migratory status and cultural orientation.

To examine whether Chinese and American cultural orientations mediate the association between migratory status and parent relationship, 122 American-born, 121 early-immigrant, and 110 late-immigrant Chinese young adults were measured on cultural orientation and parent relationship. The poorest relationships were found in the early-immigrant group. Cultural orientation mediated the difference in parent relationship between early and late immigrant groups, but not between early-immigrant and American-born groups. Implications of the findings for research and practice are discussed.

Adult↗

Asian American college students as model minorities: an examination of their overall competence.

Educational success among Asian Americans has led to their being labeled the "model minority." At the University of California, Berkeley (UCB), Asian American students have higher grade point averages (GPAs) than Hispanic and African American but not White students, supporting the notion that Asian Americans are more successful compared with other racial minorities. However, success in the classroom does not implicate effective functioning in life, and nonacademic criteria ought to be considered in assessing the validity of the model minority image. Given the increasing diversification of the United States, cross-racial engagement may be an additional contributor to overall competence. This was empirically tested in a group of 642 undergraduates at UCB, including 291 Asian, 197 White, 20 African American, 67 Hispanic, and 56 multiracial students. Overall competence was operationalized by sense of coherence, that is, the extent to which the world is experienced as comprehensible, manageable, and meaningful (A. Antonovsky, 1979, 1987). As predicted, Asian Americans had significantly fewer numbers of cross-racial groups represented in their friendship network than did students of all other races. Lower cross-racial engagement and being Asian (as compared with White) were related to a lower sense of coherence, whereas lower GPA was not. Within the Asian American subsample, cross-racial engagement was again significantly associated with greater coherence, whereas GPA again was not. Thus, extending the definition of success to overall competence, these findings raise questions about the applicability of the model minority label to Asian Americans, despite their academic achievement. Future studies need to assess the reasons for their limited cross-racial engagement and lower sense of coherence and to examine means to assist the development of these strengths.

Achievement↗

Cultural predictors of self-esteem: a study of Chinese American female and male young adults.

This study examined how specific domains of cultural orientation (language, social affiliation, and cultural pride) related to self-esteem for a sample of 174 Chinese American male and 179 Chinese American female college students. Participants completed measures of cultural orientation (General Ethnicity Questionnaire; J.L. Tsai, Y.W. Ying, & P.A. Lee, 2000) and self-esteem (M. Rosenberg, 1965). Cultural orientation significantly predicted self-esteem, above and beyond the contribution of age, gender, grade point average, and socioeconomic status. Specifically, proficiency in English and Chinese languages and pride in Chinese culture were positively correlated with self-esteem, whereas affiliation with Chinese people was negatively correlated with selfesteem. The cultural predictors of self-esteem differed for Chinese American men and women. Whereas self-esteem was mainly related to pride in Chinese culture for Chinese American women, self-esteem was mainly related to English and Chinese language proficiency for Chinese American men. Implications of these findings for understanding Asian Americans are discussed.

Adult↗

Fertility after bilateral cryptorchidism. Evaluation by paternity, hormone, and semen data.

PURPOSE: Evaluation of the fertility of a cohort of formerly bilaterally cryptorchid men in comparison with a group of formerly unilaterally cryptorchid men, and a group of control men. MATERIALS AND METHODS: Using a detailed questionnaire concerning paternity and factors related to paternity, a cohort of formerly bilateral cryptorchid men were studied and compared with men who had undergone orchiopexy for unilateral cryptorchidism, and a group of control men. All study subjects had had surgery at the Children's Hospital of Pittsburgh, Pittsburgh, Pa., between 1955 and 1975. A subset of the full cohort underwent clinical evaluation that included a physical examination, serum hormonal determination and semen analyses. RESULTS: Paternity rates are significantly lower among the formerly bilaterally cryptorchid men who have attempted to father a child (65.3%) as compared to the formerly unilaterally cryptorchid (89.7%; p < 0.001) and control men (93.2%; p < 0.001). Differences in the ability to father children are also apparent when semen and hormone levels are compared between the three groups. The bilateral group has significantly lower sperm density and inhibin B levels, and higher FSH and LH levels, than the unilateral and control groups. CONCLUSIONS: Men born with bilateral cryptorchidism have severely compromised fertility in adulthood. This reduction in fertility is clearly shown in comparisons of both paternity rates, and in semen and hormone analyses, between the formerly bilateral, formerly unilateral, and control groups.

Adult↗

Inhibin B: comparison with indexes of fertility among formerly cryptorchid and control men.

Infertility may be a consequence of cryptorchidism. We previously reported, using a large study cohort, that 38% of formerly bilateral cryptorchid men, 10% of unilateral cryptorchid men, and 5% of the control group were infertile. Men from this cohort donated blood and semen samples for inhibin B, FSH, LH, testosterone, free testosterone, and semen analyses. Results are reported comparing the entire group; some comparisons are based on normal or low sperm density. Data are also presented for men who had fathered children or had unsuccessfully attempted paternity. Mean (+/-SD) inhibin B levels were lower for the cryptorchid men (109 +/- 59 pg/mL) than the control men (153 +/- 60; P < 0.001), and FSH levels were higher (7.4 +/- 6.2 and 4.0 +/- 3.2; P < 0.0001). Inhibin B levels correlated with all other parameters for the cryptorchid group; however, correlations for the control group were only found with gonadotropins. Among the cryptorchid men, levels were significantly greater among men with normal sperm counts than men with low sperm counts (124 +/- 47 vs. 75 +/- 48 pg/mL; P < 0.0001). No difference was present for the control group (155 +/- 61 vs. 149 +/- 63 pg/mL). When the fertile group (based on paternity) vs. the infertile group (based on attempted paternity) were compared, significant differences were found for the cryptorchid group (117 +/- 62 vs. 73 +/- 52 pg/mL; P < 0.03), but not the control group (163 +/- 62 vs. 146 +/- 73 pg/mL). These data reveal relationships not apparent among the control group of men, which includes infertile men. Inhibin B data suggest that a larger portion of formerly cryptorchid men have compromised testicular function than indicated by paternity data. Low levels of inhibin B among individuals are an indication of diminished seminiferous tubule function and thus compromised potential for fertility. Low inhibin B levels together with elevated FSH levels and decreased sperm density are indicative of a high risk of infertility.

Cohort Studies↗

No relationship of testicular size at orchiopexy with fertility in men who previously had unilateral cryptorchidism.

PURPOSE: We determined whether testicular size at orchiopexy is predictive of fertility potential and whether size correlates with sperm parameters, hormone levels or testicular volume in adulthood. MATERIALS AND METHODS: Testicular size obtained from the operative notes of patients who underwent unilateral orchiopexy was classified as normal, small or large for age. These data were compared with outcome data. Paternity data were included on 166 men who reported achieving or unsuccessfully attempting paternity for 12 or more months. Of the men 49 provided blood for hormone level measurement, 43 underwent semen analysis and in 29 testicular volume was determined. RESULTS: In the 166 men, including 98, 65 and 3 with small, normal and large testes for age at orchiopexy, respectively, there was no difference in paternity based on testicular size. Of those who achieved paternity time to conception did not differ based on size. Mean age at surgery also did not differ, nor did the percent of small versus normal testes in the age categories 0 to 2, 3 to 5, 6 to 8 and 9 to 11 years. There was no difference in men with small or normal testicular size at surgery in mean luteinizing hormone, follicle-stimulating hormone, testosterone or inhibin B. Sperm density, motility and morphology, and volume in adulthood of a previously undescended testis, previously descended testis or previously undescended and descended testes did not differ in these 2 groups, although the previously undescended testis was smaller than the contralateral testis. CONCLUSIONS: In men with a history of unilateral cryptorchidism small testicular size at orchiopexy is not associated with decreased paternity (89.8%), abnormal hormone levels, a lower sperm count or decreased testicular volume in adulthood.

Child↗

Genomic sequence and transcriptional profile of the boundary between pericentromeric satellites and genes on human chromosome arm 10q.

The organization of centromeric heterochromatin has been established in a number of eucaryotes but remains poorly defined in human. Here we present 1025 kb of contiguous human genomic sequence which links pericentromeric satellites to the RET proto-oncogene in 10q11.2 and is presumed to span the transition from centric heterochromatin to euchromatin on this chromosome arm. Two distinct domains can be defined within the sequence. The proximal approximately 240 kb consists of arrays of satellites and other tandem repeats separated by tracts of complex sequence which have evolved by pericentromeric-directed duplication. Analysis of 32 human paralogues of these sequences indicates that most terminate at or within repeat arrays, implicating these repeats in the interchromosomal duplication process. Corroborative PCR-based analyses establish a genome-wide correlation between the distribution of these paralogues and the distribution of satellite families present in 10q11. In contrast, the distal approximately 780 kb contains few tandem repeats and is largely chromosome specific. However, a minimum of three independent intrachromosomal duplication events have resulted in >370 kb of this sequence sharing >90% identity with sequences on 10p. Using computer-based analyses and RT-PCR we confirm the presence of three genes within the sequence, ZNF11/33B, KIAA0187 and RET, in addition to five transcripts of unknown structure. All of these transcribed sequences map distal to the satellite arrays. The boundary between satellite-rich interchromosomally duplicated DNA and chromosome-specific DNA therefore appears to define a transition from pericentromeric heterochromatin to euchromatin on the long arm of this chromosome.

Centromere↗

No association between body mass index and beta(3)-adrenergic receptor variant (W64R) in children with premature pubarche and adolescent girls with hyperandrogenism.

OBJECTIVE: To determine if the Trp(64)Arg (W64R) variant of the beta(3)-adrenergic receptor (ADRB3) could be used as a genetic marker to define risk for polycystic ovary syndrom (PCOS) and/or obesity in children and adolescents. DESIGN: Association study. SETTING: Academic research environment. PATIENT(S): Children referred for evaluation of premature pubic hair (n = 63), adolescent girls referred for evaluation of hirsutism and/or oligomenorrhea (n = 33), and healthy adult controls (n = 67). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Relationship of body mass index (BMI) to presence or absence of W64R variant and frequency of W64R variant in our patient population. RESULT(S): Body mass index (kg/m(2)) was determined for 63 children (55 girls and 8 boys) and 33 adolescent girls. Presence or absence of the W64R variant was assayed by polymerase chain reaction (PCR) amplification followed by allele-specific restriction fragment digest. Twelve subjects and 11 healthy controls were found to be heterozygous for the W64R variant. One subject was found to be homozygous for the W64R variant. Allele frequency for the W64R variant was comparable between patients and controls. Among the patients, mean BMI values were not different between carriers and noncarriers. CONCLUSION(S): Although other studies suggest that the W64R variant is associated with the development of obesity and insulin resistance, we cannot demonstrate that it has a major effect on BMI in children with premature pubarche or in adolescent girls with hyperandrogenism. Serial observations are necessary to determine if this variant predicts the development of obesity and/or PCOS in adulthood.

Adolescent↗

The conception of depression in Chinese American college students.

The conception of depression in Chinese American college students was examined with the Center for Epidemiologic Studies--Depression Scale (CES-D). It was hypothesized that, because of their significant engagement with mainstream American culture, these students' conception of depression would better approximate White Americans' differentiated view (L. Radloff, 1977) than the general Chinese American community's integrated view (Y. Ying, 1988). A total of 353 bicultural Chinese American college students participated in the study. Consistent with the hypothesis, principal-components factor analysis with varimax rotation revealed a factor structure and loading similar to that found in White American adults. Confirmatory factor analysis also showed Chinese American college students to better approximate Radloff's differentiated model based on her White American samples than Ying's integrated model based on her Chinese American community sample. Implications of the findings and directions for future research are discussed.

Acculturation↗

Pharmacokinetics and tissue distribution of a ribozyme directed against hepatitis C virus RNA following subcutaneous or intravenous administration in mice.

A nuclease resistant ribozyme targeting the 5' untranslated region (5' UTR) of hepatitis C virus (HCV) at site 195 has been identified. To investigate the therapeutic utility of this ribozyme, we evaluated the pharmacokinetics and tissue distribution with two labeled forms of this ribozyme. [(32)P]-labeled ribozyme was administered as a single subcutaneous (SC) or intravenous (IV) bolus at a dose of 10 mg/kg or 30 mg/kg in C57Bl/6 mice. Regardless of route of administration, peak liver concentrations achieved were greater than the concentration necessary to inhibit HCV-IRES-luciferase expression in cell culture. The ribozyme was well absorbed after SC administration (89%) and had an elimination half-life of 23 minutes. To show intracellular localization of the ribozyme in target tissue, a tetramethyl rhodamine (TMR)-labeled ribozyme was administered as a single SC or IV bolus at a dose of 30 mg/kg in C57Bl/6 mice. Mice treated SC or IV with TMR-labeled ribozyme had positive fluorescence in the liver from 15 minutes to 48 hours after dosing. Definite positive fluorescence was still present at 72 hours in the mice dosed via the IV route. At early time points (15 and 30 minutes postinjection), nuclear and possibly cytoplasmic fluorescence was present in the hepatocytes, and sinusoidal fluorescence was intense. At the later time points, fluorescence became more punctate. Abundant staining was often present in Kupffer cells. This study confirms the retention of ribozyme in liver cells and supports the potential of an anti-HCV ribozyme as a therapeutic agent for treatment of chronic hepatitis C.

Animals↗

Prospective evaluation of short-term, high-volume isovolemic hemofiltration on the hemodynamic course and outcome in patients with intractable circulatory failure resulting from septic shock.

OBJECTIVE: To evaluate the effects of short-term, high-volume hemofiltration (STHVH) on hemodynamic and metabolic status and 28-day survival in patients with refractory septic shock. DESIGN: Prospective, interventional. SETTING: Intensive care unit (ICU), tertiary institution. PATIENTS: Twenty patients with intractable cardiocirculatory failure complicating septic shock, who had failed to respond to conventional therapy. INTERVENTIONS: STHVH, followed by conventional continuous venovenous hemofiltration. STHVH consisted of a 4-hr period during which 35 L of ultrafiltrate is removed and neutral fluid balance is maintained. Subsequent conventional continuous venovenous hemofiltration continued for at least 4 days. MEASUREMENTS AND MAIN RESULTS: Cardiac index, systemic vascular resistance, pulmonary vascular resistance, oxygen delivery, mixed venous oxygen saturation, arterial pH, and lactate were measured serially. Fluid and inotropic support were managed by protocol. Therapeutic endpoints were as follows during STHVH: a) by 2 hrs, a > or =50% increase in cardiac index; b) by 2 hrs, a > or =25% increase in mixed venous saturation; c) by 4 hrs, an increase in arterial pH to >7.3; d) by 4 hrs, a > or =50% reduction in epinephrine dose. Patients who attained all four goals (11 of 20) were considered hemodynamic "responders"; patients who did not (9 of 20) were considered hemodynamic "nonresponders." There were no differences in baseline hemodynamic, metabolic, and Acute Physiology and Chronic Health Evaluation and Simplified Acute Physiology Scores between responders and nonresponders. Survival to 28 days was better among responders (9 of 11 patients) than among nonresponders (0 of 9). Factors associated with survival were hemodynamic-metabolic response status, time interval from ICU admission to initiation of STHVH, and body weight. CONCLUSIONS: These data suggest that STHVH may be of major therapeutic value in the treatment of intractable cardiocirculatory failure complicating septic shock. Early initiation of therapy and adequate dose may improve hemodynamic and metabolic responses and 28-day survival.

Acid-Base Equilibrium↗

Insulin-like 3/relaxin-like factor gene mutations are associated with cryptorchidism.

Cryptorchidism is a common anomaly of male sexual differentiation. Two phases of testicular descent are recognized, transabdominal and inguinoscrotal. With evidence that androgens and Müllerian inhibitory hormone were not completely responsible for testicular descent, the existence of a third testicular hormone mediating testicular descent was postulated. Insulin-like 3 (INSL3) [also known as relaxin-like factor (RLF) and Leydig insulin-like protein (LEY I-L)] is a member of the insulin/relaxin hormone superfamily that is highly expressed in Leydig cells. The phenotype of transgenic mice with targeted deletion of the Insl3 gene was bilateral cryptorchidism with morphological evidence of abnormal gubernacular development. With this implicit evidence that Insl3 mediates testicular descent in mice, we performed mutation detection analysis of the coding regions of the 2 exon INSL3 gene in genomic DNA samples obtained from 145 formerly cryptorchid patients and 36 adult male controls. Single-strand conformational polymorphism analysis was used for the mutation detection studies. Two mutations, R49X and P69L, and several polymorphisms were identified. Both mutations were located in the connecting peptide region of the protein. The frequency of INSL3/RLF gene mutations as a cause of cryptorchidism is low, because only 2 of 145 (1.4%) formerly cryptorchid patients were found to have mutations.

Adolescent↗

Paternity and hormone levels after unilateral cryptorchidism: association with pretreatment testicular location.

PURPOSE: We determined differences in paternity and levels of the hormones inhibin B, follicle- stimulating hormone, luteinizing hormone, testosterone and free testosterone based on the preoperative location of the undescended testis in men with previous unilateral cryptorchidism. MATERIALS AND METHODS: Testicular location was determined by a review of the medical records and paternity or attempted paternity using a detailed questionnaire administered to 320 men with previous unilateral cryptorchidism. In 103 cases we performed semen analysis and measured the levels of the hormones inhibin B, luteinizing hormone, follicle-stimulating hormone, testosterone and free testosterone. Paternity, sperm count and hormonal parameters were compared with cryptorchid testicular location using analysis of variance and chi-square analysis. Logistic regression was done to analyze pretreatment testicular location as a risk factor for infertility. RESULTS: Paternity, duration of attempted conception in men who achieved paternity, sperm count and hormone levels did not differ based on pretreatment abdominal, internal ring, inguinal canal, external ring, upper scrotum or ectopic testicular location. The overall paternity rate was 90% with the lowest rate of 83.3% in the abdominal group. More than 12 months were required to achieve conception in 28.9% of the study group overall and in 39.4% of the abdominal group. Varicocele and a partner with fertility problems were risk factors for infertility, while abdominal testicular location caused borderline significant risk. CONCLUSIONS: Preoperative testicular location in men with previous unilateral cryptorchidism is not a major determinant of fertility according to paternity, sperm count or hormone levels.

Adult↗

Absence of microdeletions in the Y chromosome in patients with a history of cryptorchidism and azoospermia or oligospermia.

OBJECTIVE: To determine if cryptorchidism is associated with microdeletions of interval 6 of the Y chromosome, we evaluated this locus in men with a history of cryptorchidism with and without azoospermia or oligospermia and in a control group. DESIGN: Clinical study. SETTING: Academic research environment. PATIENT(S): Men in whom surgical treatment of cryptorchidism had been performed in childhood and healthy control male subjects. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Genotyping of interval 6 of the Y chromosome. RESULT(S): Analysis of semen obtained from men treated for cryptorchidism in childhood showed azoospermia or oligospermia in 14 of 38 (37%) men. No microdeletions were identified with polymerase chain reaction amplification of 17 distinct sequence tagged sites located on the long arm of the Y chromosome and the sex determining region on Y (SRY) gene. CONCLUSION(S): Microdeletions of interval 6 of the Y chromosome were not detected in either the formerly cryptorchid or in the healthy subjects. Although we cannot exclude the possibility of point mutations, we conclude that cryptorchidism or cryptorchidism associated with azoospermia or oligospermia is not due to microdeletions involving interval 6 of the Y chromosome.

Cryptorchidism↗