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Biomedical subjects

L Chang

Publications and source records attributed to L Chang.

At least 271 records · Page 15Linked to original sources
PubMed1995

Reassessment of adrenal androgen secretion in women with polycystic ovary syndrome.

OBJECTIVE: To reevaluate the clinical significance of elevations of adrenal androgens in polycystic ovary syndrome (PCOS). METHODS: Thirty women with PCOS and ten ovulatory controls were evaluated. Serum dehydroepiandrosterone (DHEA) sulfate and 11 beta-hydroxyandrostenedione were measured before and after 3 and 6 months of GnRH agonist (GnRH-A) therapy. All controls and 15 women with PCOS received intravenous ACTH before and after GnRH-A therapy. RESULTS: Twenty-one (70%) of the women with PCOS had elevations of DHEA sulfate, and 16 (53%) had elevations in 11 beta-hydroxyandrostenedione. Only two women with PCOS had normal values of both adrenal androgens. After GnRH-A therapy, only 11 subjects (37%) had elevated values of DHEA sulfate. Four of 16 women had reductions in 11 beta-hydroxyandrostenedione. Only those with elevated baseline DHEA sulfate levels had reductions after GnRH-A therapy. The reduction of DHEA sulfate with GnRH-A correlated with the reduction in androstenedione. Of the subjects who had reductions in DHEA sulfate with GnRH-A therapy, there was a blunted response of DHEA to ACTH after treatment. CONCLUSION: Our findings suggest that the ovary may influence the prevalence and magnitude of adrenal androgen excess in PCOS.

Adrenocorticotropic Hormone↗
PubMed1995

Analysis of brain tumors using 1H magnetic resonance spectroscopy.

BACKGROUND: Magnetic resonance imaging (MRI) is superior in delineating anatomic and pathologic information and has subsequently been married to the ability of magnetic resonance spectroscopy (MRS) to provide insight into the biochemical changes underlying pathology. Proton magnetic resonance spectroscopy (1H MRS) allows the non-invasive in vivo collection and measurement of chemical information from a selected volume of tissue (voxel). METHODS: We conducted a prospective trial in 23 patients with brain mass lesions and 16 normal subjects using proton magnetic resonance spectroscopy (1H MRS). The spectra were analyzed for N-acetyl-aspartate (NAA), choline compounds (Cho), creatine (Cr), and lactate (Lac). The ratios of the compounds in tumors were compared to normals. RESULTS: The tumors showed significant decreases in the mean peak height ratios of NAA/Cho, NAA/Cr, and significant increases in Cho/Cr when compared to tissue from normal subjects. Cho was elevated in all of the meningiomas and gliomas. In benign tumors, Cho was usually elevated while in metastases Cho was often normal or decreased. The four metastatic tumors showed NAA/Cho, NAA/Cr, and Cho/Cr that were similar to controls. Lac varied with tumor type and was elevated in many malignant primary brain tumors. CONCLUSIONS: 1H MRS is a powerful tool for safe, noninvasive analysis of tissue chemistry in vivo. Analysis of intracranial tumors reveals significant trends that might eventually be used in the classification of tumor histology and evaluation of the efficacy of tumor treatment.

Adult↗
PubMed1995

Retinoic acid induction of mouse cellular retinoic acid-binding protein-I gene expression is enhanced by sphinganine.

Cellular retinoic acid-binding protein-I (CRABP-I) gene expression is induced in mouse embryonal carcinoma P19 cells specifically by retinoic acid (RA) and the induction is enhanced by sphinganine. The effects of retinoic acid and sphinganine on CRABP-I gene expression can be accounted for by a stimulation of its transcription rate. Using a lacZ reporter system, it was determined that a DNA fragment containing a putative AP-1 binding site in the promoter region of CRABP-I gene is required for the up-regulation of CRABP-I gene transcription.

Animals↗
PubMed1995

Low-dose growth hormone-releasing factor may enhance folliculogenesis in regularly menstruating women: a preliminary study.

OBJECTIVE: To evaluate the effect of low-dose GH-releasing factor (GRF) on folliculogenesis in regularly menstruating women. DESIGN: Prospective clinical trial where individual patients served as their own control. SETTING: Outpatient Reproductive Endocrine/Infertility Clinic of the Los Angeles County-University of Southern California Medical Center, Los Angeles, California. PATIENTS: Seven regularly menstruating women. INTERVENTION: During treatment cycles, subjects received 100 micrograms SC GRF on cycle days 2 to 11 and were observed during a control cycle. MAIN OUTCOME MEASURES: Follicle number and diameter, as well as endometrial thickness were all assessed by vaginal ultrasound and blood was obtained for serum FSH, LH, E2, P, GH, insulin-like growth factor 1 (IGF-1), and insulin-like growth factor binding protein-3. RESULTS: During cycles treated with GRF, GH, and IGF-1 levels were normal. However, follicular growth rates and E2 to FSH ratios were significantly higher. The day of the peak E2 to follicular diameter ratio after GRF was earlier than in control cycles. Endometrial growth rates were also greater with GRF. CONCLUSIONS: Our data, although preliminary, support the hypothesis that low doses of GRF may independently stimulate the ovary and enhance folliculogenesis.

Adult↗
PubMed1995

Metabolism of dihydrotestosterone to 5 alpha-androstane-3 alpha, 17 beta-diol glucuronide is greater in the peripheral compartment than in the splanchnic compartment.

OBJECTIVE: To compare the peripheral versus the splanchnic contribution to the formation of 3 alpha-diol G. DESIGN: Prospective study in various groups of women and men. SETTING: Reproductive Endocrine service of our University Medical Center. PATIENTS: Six normal ovulatory women, five hirsute women with polycystic ovary syndrome, and six normal men. INTERVENTIONS: All subjects received IV dihydrotestosterone (DHT) infusions as well as percutaneous administration of DHT. Serum was obtained at multiple time points before and after each administration of DHT. MAIN OUTCOME MEASURES: Comparison of serum levels of DHT, 3 alpha-androstanediol (3 alpha-diol), 3 alpha-diol G, and androsterone glucuronide in the three groups. RESULTS: Steady-state levels of DHT were similar in the three groups and were also similar after the two different routes of administration. However, ratios of 3 alpha-diol G to DHT were significantly greater after percutaneous gel than after IV administration in all three groups. This also was the case for the ratio of unconjugated serum 3 alpha-diol to DHT. Levels of androsterone glucuronide were similar with the different routes of administration. CONCLUSION: Using normal routes of administration and, in attempting to assess in vivo metabolism of DHT, our data confirm that the skin is the major site of unconjugated 3 alpha-diol and 3 alpha-diol G formation. Serum 3 alpha-diol G, therefore, appears largely to reflect skin DHT metabolism.

Administration, Cutaneous↗
PubMed1995

Prevalence of psychiatric symptoms and their relation to adjustment among Chinese-American youth.

OBJECTIVE: The primary purpose of this investigation is to assess psychiatric symptoms of Chinese-American children using Achenbach's Child Behavior Checklist (CBCL) and to determine the impact of acculturation on these symptoms. METHOD: One hundred eighty-one forms of a Chinese CBCL and a 10-item questionnaire on adjustment and ethnic patterns of socialization were completed by a parent or guardian of Chinese-American children attending a Chinese school in New York City. RESULTS: The sample's total problem, internalizing, externalizing, total competence, activities, and social scores were significantly lower than Achenbach's American norms by age and sex. Favorable adjustment was correlated significantly with lower total problem and internalizing scores. Recent immigrants did not have higher symptom scores. CONCLUSION: Lower scores of the Chinese-American children may be due to temperamental differences, underreporting by the respondent, or cultural intolerance of misbehavior.

Acculturation↗
PubMed1995

Alpha 1-antitrypsin deficiency and anti-proteinase 3 antibodies in anti-neutrophil cytoplasmic antibody (ANCA)-associated systemic vasculitis.

alpha 1-antitrypsin (alpha 1-AT) is a naturally occurring inhibitor of proteinase 3 (PR3) and elastase, two of the target antigens of anti-neutrophil cytoplasmic antibodies (ANCA). An increased incidence of alpha 1-AT phenotypes associated with dysfunctional alpha 1-AT or low serum levels has been reported in patients with anti-PR3 antibodies. We have studied the relationship between ANCA, and phenotypes and serum levels of alpha 1-AT. Phenotypes usually associated with a moderate or severe reduction in alpha 1-AT serum levels or in dysfunctional activity were found more often in individuals with anti-PR3 antibodies than in the general population: four of the 31 patients (13%) with anti-PR3 antibodies had phenotypes MZ (n = 2), S (n = 1) or Z (n = 1) (P < 0.05). However, the corresponding alpha 1-AT serum levels were normal (n = 3) or elevated (n = 1). None of the 31 sera with anti-PR3 antibodies had low levels of alpha 1-AT. No abnormal alpha 1-AT phenotype was demonstrated in seven patients with anti-elastase antibodies, despite a low level of alpha 1-AT in one serum. Anti-myeloperoxidase antibodies are common in patients with ANCA, but no abnormal phenotype or low serum alpha 1-AT level was demonstrated in any of 29 sera containing these antibodies. Finally anti-glomerular basement membrane (GBM) antibodies occur occasionally in patients with ANCA-associated diseases, but again none of 10 sera had an abnormal alpha 1-AT phenotype or low serum level. ANCA were not demonstrated by indirect immunofluorescence in any serum from 73 patients with abnormal alpha 1-AT phenotypes. These results confirm that patients with anti-PR3 antibodies often have alpha 1-AT phenotypes that are usually associated with low serum levels of alpha 1-AT or with dysfunctional protein. Nevertheless, the incidence of anti-PR3 antibodies in patients with abnormal alpha 1-AT phenotypes is very low. This probably reflects the rarity of Wegener's granulomatosis, the major disease associated with anti-PR3 antibodies, and the relative frequency of abnormal alpha 1-AT phenotypes. The mechanism for the development of anti-PR3 antibodies in patients with abnormal alpha 1-AT phenotypes is not clear, but may relate to the increased propensity of unbound and uninhibited PR3 to stimulate autoantibody production.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1995

Epitope mapping of anti-proteinase 3 and anti-myeloperoxidase antibodies.

Anti-proteinase 3 (PR3) and anti-myeloperoxidase (MPO) autoantibodies are present in many patients with Wegener's granulomatosis (WG) and microscopic polyarteritis. The aim of this study was to determine whether these antibodies bound to linear peptide sequences on their target antigens. If common linear epitopes were demonstrated, then these could be manufactured and used in diagnostic ELISAs for anti-PR3 and anti-MPO antibodies. In addition, any homology between these epitopes and bacterial or viral sequences might implicate those microorganisms in the development of these antibodies and the pathogenesis of the associated diseases. The presence of linear epitopes on PR3 and MPO was suggested by the binding of the corresponding autoantibodies to these proteins after they had been reduced with beta-mercaptoethanol (beta-ME) and denatured with SDS or boiling, and digested with proteases. Four of the 22 sera with anti-PR3 antibodies bound to PR3 in Western blots after treatment with SDS, beta-ME and boiling for 5 min. Thermal denaturation reduced the amount of binding more than other forms of denaturation. One serum with anti-PR3 antibodies bound to Lys-C and Glu-C-digested PR3 in dot blots. Linear epitopes could not be further defined by their binding in an ELISA using overlapping peptides corresponding to the PR3 molecule because of non-specific binding. Three of the five sera with anti-MPO antibodies bound to MPO in Western blots after treatment with SDS, beta-ME and boiling for 5 min. One serum with anti-MPO antibodies bound to Lys-C and Glu-C-digested MPO in dot blots. Again, linear epitopes could not be further defined using an ELISA with overlapping peptides because of non-specific binding. Some anti-PR3 and anti-MPO antibodies are likely to recognize linear epitopes, but these cannot be defined by use of a PIN ELISA system.

Amino Acid Sequence↗
PubMed1995

Localized in vivo 1H magnetic resonance spectroscopy and in vitro analyses of heterogeneous brain tumors.

Results of magnetic resonance spectroscopic (MRS) studies of the chemical patterns in brain tumors have been inconsistent. Actual biochemical correlations are needed. In 2 patients with heterogeneous intracranial tumors, in vivo 1H MRS and in vitro biochemical analyses were correlated. Histology confirmed the tumor heterogeneity. Choline was elevated in the cellular portion of both tumors but decreased in the necrotic or cystic portions. Creatine was diffusely decreased while lactate was elevated in all regions of both tumors. Furthermore, the increase in the choline peak on 1H MRS appeared to be due to increases in water-soluble choline compounds. This study illustrates the value of small localized voxels for differentiating regional chemical differences in tumors.

Adult↗
PubMed1995

Brain lesions in patients with AIDS: H-1 MR spectroscopy.

PURPOSE: To evaluate the role of proton (hydrogen-1) magnetic resonance (MR) spectroscopy in the differential diagnosis of focal brain lesions in patients with acquired immunodeficiency syndrome (AIDS). MATERIALS AND METHODS: Twenty-six men with 35 AIDS-related brain lesions underwent MR imaging and localized H-1 MR spectroscopy. Lesions consisted of 11 toxoplasmic abscesses, 12 progressive multifocal leukoencephalopathic lesions, eight lymphomas, and four cryptococcomas. Metabolite peak areas in the lesions were compared with those in the contralateral hemisphere in each patient. RESULTS: H-1 MR spectroscopic findings showed significantly different biochemical profiles for each diagnostic group (P = .0001) with regard to N-acetyl compounds, total creatine pool, choline-containing compounds, myoinositol, and lactate. H-1 MR spectroscopy alone helped correctly diagnose 94% (84% with jackknifed classification) of the brain lesions, without overlap between toxoplasmosis and lymphoma. CONCLUSION: H-1 MR spectroscopy is a sensitive and potentially specific noninvasive adjunctive method for differential diagnosis of focal brain lesions in AIDS.

AIDS Dementia Complex↗
PubMed1995

A prospective randomized trial comparing finasteride to spironolactone in the treatment of hirsute women.

Enhanced 5 alpha-reductase activity has been found in the skin of the majority of women with hirsutism. Finasteride is a specific competitive inhibitor of 5 alpha-reductase, preferentially inhibiting the type 2 isoenzyme. Therefore, we randomly assigned 14 hirsute women in a 2:1 ratio to 1 of 2 treatment arms: 1) finasteride (F) treatment (n = 9; 5 mg, orally, daily), or 2) spironolactone (S) treatment (n = 5; 100 mg, orally, daily). Each group was treated for 6 months. Patients were evaluated at baseline and after 3 and 6 months of treatment. The 2 groups were similar in age, weight, hip/waist ratio, baseline Ferriman-Gallwey score (F, 19 +/- 2; S, 19 +/- 2), and baseline androgen levels. Finasteride treatment resulted in a significant increase in testosterone (T; P < 0.01) and the T/dihydrotestosterone ratio (P < 0.01). Finasteride caused a significant decrease in 5 alpha-androstane-3 alpha,17 beta-diol glucuronide (3 alpha-diolG; P < 0.05), the 3 alpha-diolG/T ratio (P < 0.01), and the 3 alpha-diolG/androstenedione ratio (P < 0.05). All changes were consistent with 5 alpha-reductase inhibition. In contrast, spironolactone treatment did not result in significant changes in serum hormone levels. Both treatments produced a significant decrease in anagen hair diameters [F, -14.0 +/- 6.7% (P < 0.05); S, -13.4 +/- 3.8% (P < 0.05)] and Ferriman-Gallwey scores [F, -2.1 +/- 0.4 (P < 0.05); S, -2.5 +/- 0.7 (P < 0.05)]. In conclusion, despite significantly different effects on androgen levels, finasteride and spironolactone treatment resulted in a similar clinical effect on hirsutism. Both caused significant, but limited, improvement in hirsutism. Although promising, further studies with finasteride are needed to verify its effectiveness as a treatment for hirsutism. Such studies will also provide a better understanding of the relative contribution of 5 alpha-reductase isoenzymes to hirsutism.

Adolescent↗
PubMed1995

The impact of estrogen on adrenal androgen sensitivity and secretion in polycystic ovary syndrome.

Adrenal hyperandrogenism is a common feature of patients with polycystic ovary syndrome (PCO). This may be due to enhanced adrenal sensitivity to ACTH. Because enhanced ovarian androgen secretion does not appear to explain this phenomenon, we explored the role of estrogen in inducing enhanced adrenal sensitivity, in that a state of relative hyperestrogenism exists in PCO. Eight patients with PCO and seven matched controls received ovine corticotropin-releasing hormone (oCRH; 0.1 micrograms/kg) iv before and after hypoestrogenism was induced by leuprolide acetate (LA; 1 mg, sc, each day). In patients with PCO, a third oCRH test was repeated after transdermal estradiol (E2; 0.1 mg) had been applied for a week, during which time LA was continued. At baseline, patients with PCO had increased responses of 11 beta-hydroxyandrostenedione and dehydroepiandrosterone (P < 0.03 and P < 0.02) and increased delta maximal ratios of androstenedione (A4)/ACTH and dehydroepiandrosterone/ACTH (P < 0.01) after oCRH treatment. After LA administration to patients with PCO, these ratios were significantly suppressed (P < 0.01) and returned to baseline after E2 was added. There were no changes in controls. Steroid ratio responses to oCRH suggested that 17,20-desmolase activity (delta maximum change in the ratio of A4/17-hydroxyprogesterone) was lowered with estrogen suppression and increased again after transdermal E2 administration. There was a significant positive correlation between changes in E2 levels and delta maximum change in the ratios of A4/17-OHP after oCRH treatment, signifying 17,20-desmolase activity (r = 0.58, P < 0.02). In conclusion, these data provide evidence that estrogen is at least one factor that influences adrenal androgen sensitivity in PCO and may help explain the frequent finding of adrenal hyperandrogenism in this syndrome.

17-alpha-Hydroxyprogesterone↗
PubMed1995

Elevation of microtubule-associated protein tau in the cerebrospinal fluid of patients with Alzheimer's disease.

Currently, there is no biochemical marker clinically available to test for the presence of Alzheimer's disease (AD). Recent studies suggest that the core component of AD-associated neurofibrillary tangles (NFTs), the microtubule-associated protein tau, might be present in CSF. This study focuses on establishing both the presence of tau in CSF and its potential utility in the diagnosis of AD. We obtained CSF from 181 individuals; 71 of these were diagnosed as having probable AD by NINCDS-ADRDA criteria. The remaining 110 individuals were divided into three groups: (1) age-matched demented non-AD patients (n = 25), (2) neurologic controls (n = 59), and (3) other controls (n = 26). We developed a sensitive enzyme-linked immunosorbent tau assay using monoclonal antibodies prepared against recombinant human tau. We confirmed specificity of the antibodies by a combination of immunoprecipitation and immunoblot results. By this assay we measured that the AD population has a mean level of tau 50% greater than the non-AD dementia patients. Comparing AD patients with all other groups, the difference in tau levels as analyzed by one-way ANOVA is highly statistically significant (p < 0.001). Postmortem analysis of two AD patients with high levels of CSF tau revealed a high density of NFTs in the hippocampus. There was no significant correlation between tau and age in the non-AD groups. This study suggests that CSF tau is elevated in AD and might be a useful aid in antemortem diagnosis.

Aged↗
PubMed1995

[Stimulating action of Carthamus tinctorius L., Angelica sinensis (Oliv.) Diels and Leonurus sibiricus L. on the uterus].

The experimental results indicate that the decoction of Chinese drugs Carthamus tinctorius, Angelica sinensis and Leonurus sibiricus has stimulating action on the uterus of mouse in vitro. The stimulating action of Carthamus tinctorius and Leomurus sibiricus has been found related to stimulating H1-receptor and alpha-adrenergic receptor of uterus, but the action of Angelica sinensis to stimulating H1-receptor of uterus only.

Animals↗
PubMed1995

[Post-operative radiotherapy of glioma in the cerebral hemisphere in adult--a retrospective study of 326 cases].

Three hundred twenty-six cases of adult patients with glioma in the cerebral hemisphere treated by post-operative radiotherapy at the General Hospital, Tianjin Medical University from 1976 through 1990 were reviewed. The 1-, 3-, 5- and 10-year survival rate was 76.8%, 62%, 55.7% and 42.1%, respectively in low grade gliomas and the 1-, 3-, and 5-year survival rate was 44.3%, 35% and 27.1% respectively in high grade gliomas. In this study, patients' age, performance status before radiotherapy and histopathologic type of the tumor are important factors influencing the treatment outcome. There is no correlation between radiation dose and survival rate. Since 1988, combined photon and electron beams from linear accelerator have been used with a total dose of 65-70Gy to the target area.

Adolescent↗
PubMed1995

[Changes in serum granulocyte colony-stimulating factor (G-CSF) in burned patients].

Serum G-CSF level was assayed in 20 burned patients (TBSA > or = 30%) 2 weeks postburn. In 11 of them plasma endotoxin was also measured. The results showed serum G-CSF level was increased in 87.5% (7/8) of burned patients with exceeding 50% TBSA and in 58.3% (7/12) of patients with 30%-50% TBSA, and in the former it was earlier increased (1-5 day postburn) than the latter (5-11 day postburn). Serum G-CSF was increased in 90% of the burned patients with wound sepsis. Increased of serum G-CSF in burned patients, especially in those exceeding 50% TBSA, indicates the occurrence of sepsis.

Burns↗