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Biomedical subjects

Z Harel

Publications and source records attributed to Z Harel.

At least 19 recordsLinked to original sources
PubMed2001

Antibodies against human putamen in adolescents with anorexia nervosa.

OBJECTIVE: To examine whether antiputamen antibodies are present in adolescents with anorexia nervosa (AN). METHOD: Using enzyme-linked immunosorbent assay (ELISA) with an extract of human putamen as an antigen, sera samples obtained from 22 adolescents with active AN and from 22 healthy adolescents (control group) were assayed for antibodies to neuronal components RESULTS: Mean optical density (OD) readings for serum antibodies against human putamen in adolescents with AN was significantly greater than the mean OD readings in the control group (0.492 +/- 0.086 vs. 0.275 +/- 0.028, p =.02). When serum positivity was defined as an OD level greater than 2 SD above the mean control group value (0.541), antiputamen antibodies were detected in the blood of 6 AN patients (27%) whereas they were detected in the blood of 1 patient (5%) in the control group (p <.05; Fisher's exact test). DISCUSSION: The detection of antiputamen antibodies in adolescents with AN suggests an underlying immune process at the putamen level in some patients with this eating disorder.

Adolescent↗
PubMed2001

Serotesting versus presumptive varicella vaccination of adolescents with a negative or uncertain history of chickenpox.

OBJECTIVE: To review the current practice of adolescent health care providers when an adolescent reports a negative or uncertain history of chickenpox in order to provide information for future practice. METHODS: Retrospective chart review of a sample of patients seen in a hospital-based adolescent primary care clinic between 1996 and 1999. RESULTS: Among adolescents who reported a positive history of chickenpox (190 patients, aged 15 +/- 1 years), varicella occurred before age 5 years in 30%, between 5 and 10 years in 56%, and at older than age 10 years in 14% of the patients. When adolescents reported a negative or uncertain history of varicella (55 patients, aged 15 +/- 1 years), serotesting was ordered for the majority (73%) of cases, while only 16% were presumptively vaccinated with varicella vaccine. In six patients no intervention was noted in the charts, and these patients were contacted. In 80% of the patients who were serotested, varicella IgG titers of > or = 1:32 indicated a previous unnoticed infection and lifelong immunity to varicella. In only 20% of the patients sera were negative for varicella IgG titer, requiring varicella vaccination. There was no statistical difference between the number of siblings of patients with a positive serologic test (3 +/- 1) and the number of siblings of seronegative patients (2 +/- 1, p = 0.41). Seven of the eight seronegative patients consented to varicella vaccination and were vaccinated within 10 months of serotesting. CONCLUSIONS: These data support the practice of serotesting for a previously unnoticed varicella infection rather than presumptive vaccination in the adolescent age group. A follow-up vaccination of seronegative adolescents should be scheduled as close to serotesting as possible.

Adolescent↗
PubMed2001

Omega-3 polyunsaturated fatty acids in adolescents: knowledge and consumption.

OBJECTIVE: To assess adolescents' knowledge about n-3 polyunsaturated fatty acids (PUFA) and their dietary intake of these important nutrients. METHODS: A questionnaire consisting of 12 questions assessing the knowledge and intake of n-3 PUFA and of a 24-h dietary recall was administered to 1117 ninth-grade adolescents (52% girls and 48% boys) attending five public schools. The adolescents were subsequently provided with verbal and written information on the health benefits, requirements, and dietary sources of n-3 PUFA. Dietary recalls were analyzed for energy and n-3 PUFA intake. Descriptive statistics, Student's t-tests, Chi-square analysis, and multiple regression analysis were used to assess adolescents' knowledge about n-3 PUFA as well as to examine relationships of independent variables with n-3 PUFA intake. RESULTS: Most adolescents (89%) believed that eating fish, a main source of very long chain (VLC) n-3 PUFA, is healthy and may prevent heart disease (59%), but only a few knew about n-3 PUFA's role in alleviating inflammation (29%) and its potential for cancer prevention (25%). Many were aware of marine sources of n-3 PUFA, such as salmon (67%), tuna (46%), mackerel (30%), and herring (26%), but only 36% knew about adequate intake of VLC n-3 PUFA. The main source of n-3 PUFA information was parents (58%), whereas only 21% of adolescents reported that their care providers had discussed health benefits of n-3 PUFA with them. About one-third of adolescents consumed fish at least once a week, and 29% consumed fish once a month. Dislike (22% of participants) and allergy (3%) were the main reasons for rarely (< or = 3 times/year; 18%) or never (17%) consuming fish. Only one adolescent reported daily consumption of a fish concentrate supplement. Daily consumption of linolenic acid was higher in boys (0.38 +/- 0.02 g) than in girls (0.31 +/- 0.01 g; p =.002). Total intake of n-3 PUFA represented only 30% of the presently available (Canadian) recommended daily allowance (CRDA) for 14- to 15-year-old boys (1.4 g/day) and 29% of the CRDA for 14- to 15-year-old girls (1.2 g/day). CONCLUSIONS: Adolescents are aware of some of the health benefits of n-3 PUFA but lack concrete information about dietary requirements of n-3 PUFA and about n-3 PUFA content of various dietary sources.

Adolescent↗
PubMed2001

Aromatase p450 expression in a feminizing adrenal adenoma presenting as isosexual precocious puberty.

A 7-yr-old girl presented with isosexual precocious puberty secondary to a feminizing adrenal adenoma. The adrenal tumor was found to express aromatase messenger ribonucleic acid. Enzyme kinetic studies revealed a high level of aromatase activity in the adrenal tumor, with a K(m) of 45 nmol/L and a maximum velocity of 25.6 pmol/mg.h. Aromatase activity was approximately 500-fold higher in the tumor than in adjacent normal adrenal tissue. Although histopathological examination of the tumor was most consistent with a benign adenoma, the aromatase transcripts present in the tumor corresponded to those previously associated with malignant as well as benign tumors. We consider the pattern of aromatase expression sufficient to warrant continued follow-up for tumor recurrence. Our case demonstrates that isosexual precocious puberty secondary to a feminizing adrenal tumor can be due to estrogen synthesis from the tumor itself rather than peripheral aromatization as had been previously theorized.

Adenoma↗
PubMed2000

Urinary leukotriene (LT) E(4) in adolescents with dysmenorrhea: a pilot study.

In the present study we measured levels of urinary leukotriene (LT) E(4) as an index of LT production during the menstrual cycle in adolescents. Mean urinary LTE(4) levels in girls with dysmenorrhea was approximately threefold higher than normal laboratory values on Day 1 of the menstrual period and approximately twofold higher than normal laboratory values on Day 5 of the menstrual period. Compared with urinary LTE(4) levels in girls with eumenorrhea, urinary LTE(4) levels in girls with dysmenorrhea were higher on Day 1 [361 +/- 123 pg/mg creatinine vs. 122 +/- 37 pg/mg creatinine, p =.1; not significant (NS)] and on Day 5 (202 +/- 26 pg/mg creatinine vs. 117 +/- 26 pg/mg creatinine, p <.05) of the menstrual period, as well as on Day 10 (159 +/- 33 pg/mg creatinine vs. 88 +/- 21 pg/mg creatinine, p =.1; NS) of the menstrual cycle. Increased urinary excretion of leukotrienes, inflammatory mediators known to cause potent vasoconstriction and uterine contractions, in girls with dysmenorrhea in this pilot study, suggests that these mediators may be involved in generating dysmenorrhea symptoms in adolescents.

Adolescent↗
PubMed2000

Adolescents: at increased risk for osteoporosis?

Perhaps the most important factor in the primary prevention of osteoporosis is the attainment of an optimal peak bone during adolescence. In addition to endogenous factors, such as genetic and ethnic background, environmental factors such as dietary habits, physical activity, and sex hormone therapy, influence the accretion of bone mass during this critical period of skeletal growth. First, calcium dietary intake in adolescents is generally well less than the current recommended RDA of 1200 mg/day. Multiple studies of children and adolescents have demonstrated increases in bone mass with dietary calcium supplementation. Second, regarding physical activity, the overall impression is that a moderate amount of particularly weight-bearing exercise has a positive impact on bone. There appears, however, to be a threshold of intensity of physical activity over which a negative impact on bone occurs, particularly when the exercise is of an anaerobic nature or occurring in very thin, amenorrheic participants. Third, previous research suggests that the various forms of hormonal contraception exert differing effects on bone mass in adolescents, with levonorgestrel implants and combined oral contraceptives may be associated with a more positive effect on bone mass compared with that observed with depot medroxyprogesterone acetate. From a clinical perspective, approaches to optimizing peak bone mass in adolescents would include increasing calcium intake, whether in the form of dairy products, fortified foods, or supplements as well as encouraging participation at a moderate level, in weight-bearing exercise. Last, in adolescents with extensive risk factors and predicted long duration of use, subdermal implants or combined oral contraceptives may be the optimal hormonal methods of birth control.

Adolescent↗
PubMed1999

The use of long-acting contraceptives in adolescents.

DMPA and implants have played an important role in the attempt to prevent teenage pregnancies. Adolescent health care providers should provide continued counseling to girls using DMPA or implants and should promptly address any concern associated with these methods. Future studies are warranted to explore ways to prevent or reduce the side effects of DMPA and implants, as well as to develop new, optimal, long-acting contraceptives. Detailed baseline information should be obtained in every future study that explores the presence of side effects during the use of long-acting contraceptives.

Adolescent↗
PubMed1999

New developments in adolescent nutrition.

Many adolescents are not aware of optimal dietary requirements and this lack of knowledge may adversely affect their present well-being and future health. Adolescent health providers, nurses, dietitians and health teachers should disseminate information about dietary requirements and about important nutrients for adolescents.

Adolescent↗
PubMed1998

Adolescents and calcium: what they do and do not know and how much they consume.

PURPOSE: To assess knowledge about calcium and dietary intake among a sample of adolescents. METHODS: A survey consisting of 24-h dietary recall and 14 questions assessing knowledge about calcium was administered to 1117 adolescents (52% girls and 48% boys) attending the ninth grade in five public schools. RESULTS: A majority (98%) believed that dietary calcium is healthy, strengthens the bones (92%), and may prevent osteoporosis (51%), but only a few were aware of the role of calcium in neuromuscular function (20%) and blood pressure regulation (15%). About 60% knew that adolescence is a critical period for peak bone mass accretion. Only 19% were aware of the recommended dietary allowance (RDA) of calcium for adolescents [4 servings (1200 mg)/day]. The majority knew that dairy products are the main dietary source of calcium, but only 10% were aware of the calcium content of various dairy products. Only 45% knew about nondairy sources of calcium. The adolescents' main sources of calcium information were health teachers (55%) and parents (46%), while only 38% reported that their health care providers had discussed health benefits of calcium. Dairy products accounted for most of the reported daily calcium intake, and the majority (79%) reported consuming dairy products daily. "Dislike" and allergy were the main reasons given for not consuming dairy products. One third reported daily supplementation with vitamins and minerals, 68% of which contained 100-200 mg of elemental calcium. Calculated calcium intake (foods, beverages, and supplements) was 536 +/- 19 mg/24 h (45% of RDA) in girls and 681 +/- 28 mg/24 h (57% of RDA) in boys (p < 0.0001). CONCLUSIONS: While adolescents are aware of the main health benefits of calcium, they lack specific information about daily requirements and calcium content of the various dietary sources. This lack of information may contribute to adolescents' suboptimal intake of calcium.

Adolescent↗
PubMed1997

On the need to screen for Chlamydia and gonorrhea infections prior to colposcopy in adolescents.

PURPOSE: The purposes of this study were to explore the association of pelvic inflammatory disease (PID) with cervical biopsy and to examine whether screening for Chlamydia and gonorrhea infections within 2 weeks prior to colposcopy is a standard clinical practice among adolescents' care providers in the United States. METHODS: An anonymous questionnaire was distributed to U.S. physicians and nurses who are members of the Society for Adolescent Medicine, and/or the North American Society for Pediatric and Adolescent Gynecology. RESULTS: A total of 368, from all the states in America, responded. Only 5% of the respondents have encountered biopsy-associated PID owing to Chlamydia and/or gonorrhea. The incidence rate of biopsy-associated PID reported by the respondents to this survey was approximately 1:1000 colposcopic biopsies. Fifteen percent of the respondents screen their adolescent patients, and 23% favor screening for Chlamydia and gonorrhea infections within 2 weeks prior to colposcopy. Previous experience with colposcopy and previous encounters with biopsy-associated PID in adolescents did not significantly affect the practice or the opinion of the respondents. CONCLUSIONS: Screening for Chlamydia and gonorrhea infections within 2 weeks prior to colposcopy in adolescents is presently not a common clinical practice among U.S. adolescents' care providers. Because of the potential risk of biopsy-associated PID, it is advisable to minimize the interval between Chlamydia and gonorrhea screening and colposcopy in adolescents.

Adolescent↗
PubMed1996

Adolescents' reasons for and experience after discontinuation of the long-acting contraceptives Depo-Provera and Norplant.

PURPOSE: The objectives of this study were to examine the reasons for discontinuation of the long-acting contraceptives Depo-Provera and Norplant in adolescents, and to assess the adolescents' experience after discontinuation of the methods. METHODS: A total of 35 adolescents [gynecologic age 4.7 +/- 0.3 years, and body mass index (BMI) 24.2 +/- 0.6] who discontinued Depo-Provera, and 31 adolescents (gynecologic age 3.4 +/- 0.3 years, BMI 24.1 +/- 0.9) who discontinued Norplant were periodically assessed during use of the methods and up to 12 months after discontinuation. RESULTS: The most common reasons for discontinuation of both Norplant (after 21.8 +/- 1.6 months of use) and Depo-Provera (9.2 + 0.9 months of use) were irregular menstrual bleeding (64%), weight gain (41%), and increased headaches (30%). Resumption of menstrual regularity and dysmenorrhea was noted sooner after discontinuation of Norplant, compared with Depo-Provera. The increase in BMI noted at discontinuation of Depo-Provera (1.1, P = .0005) and Norplant (1.3, P = .03) persisted up to 6 months after discontinuation of either method (0.6, P = .01 post-Depo-Provera discontinuation; and 0.9, P = 0.02 post-Norplant discontinuation). Only 62% of the adolescents reported no break in contraceptive practice. The condom was the most popular method (37%) after discontinuation of Depo-Provera, and oral contraceptive (39%) after discontinuation of Norplant. The cumulative conception proportion reached 0.93 at 12 months after discontinuation of Norplant, and was significantly higher (P = .01) compared with the cumulative proportion of conception after discontinuation of Depo-Provera (P = .50). CONCLUSIONS: Health care providers should aggressively manage physical problems associated with Depo-Provera and Norplant use, and expedite the transition to a new contraceptive method to minimize the high pregnancy rate observed after discontinuation of these methods in adolescents.

Adolescent↗
PubMed1996

Supplementation with omega-3 polyunsaturated fatty acids in the management of dysmenorrhea in adolescents.

OBJECTIVES: The purpose of the study was to examine whether dietary supplementation with omega-3 fatty acids can relieve symptoms of dysmenorrhea in adolescents. STUDY DESIGN: Forty-two adolescents with dysmenorrhea were randomly allocated to two groups. In the first group 21 girls received fish oil (1080 mg icosapentaenoic acid, 720 mg docosahexaenoic acid, and 1.5 mg vitamin E) daily for 2 months followed by a placebo for an additional 2 months. In the second group 21 girls received placebo for the first 2 months, followed by fish oil for 2 more months. The Cox Menstrual Symptom Scale was used to assess response to treatment. RESULTS: There were no significant differences in the Cox Menstrual Symptom Scale between the two groups at baseline after 2 months of placebo administration. After 2 months of treatment with fish oil there was a marked reduction in the Cox Menstrual Symptom Scale from a baseline mean value of 69.9 to 44.0 (p < 0.0004). CONCLUSIONS: This study suggests that dietary supplementation with omega-3 fatty acids has a beneficial effect on symptoms of dysmenorrhea in adolescents.

Adolescent↗
PubMed1995

Effects of long term treatment with sertraline (Zoloft) simulating hypothyroidism in an adolescent.

A 16-year-old depressed adolescent, who had received sertraline treatment for the previous 18 months, developed insomnia, daytime somnolence and lack of energy. His thyroid function tests revealed low levels of total T4 with normal levels of free T4 and TSH, and a normal thyrotropin-releasing hormone (TRH) stimulation test. Discontinuing sertraline resulted in improved sleep and disappearance of daytime somnolence. Although daytime somnolence and low levels of total T4 can mimic hypothyroidism, in this case sertraline only displaced the bound-fraction of total T4 and was not associated with true hypothyroidism.

1-Naphthylamine↗
PubMed1995

Depo-Provera in adolescents: effects of early second injection or prior oral contraception.

PURPOSE: To examine the effects of an early second injection or prior use of oral contraceptive pills (OCP) on side effects of Depo-Provera during the early months of use in adolescents. METHODS: Thirty-six girls, gynecologic age 4.2 +/- 0.3 years, and body mass index (BMI) 23.2 +/- 0.8, received the currently recommended injection of 150 mg every three months. Twenty-seven girls (gynecologic age 3.9 +/- 0.5 years, BMI 24.0 +/- 0.8) received the second injection six weeks after the first injection. Fifteen girls (gynecologic age 5.0 +/- 0.5, BMI 25.4 +/- 1.3) switched directly from an OCP to Depo-Provera. The patients were periodically assessed by their care providers. RESULTS: Early administration of the second injection of Depo-Provera did not alter the bleeding episodes, onset of bleeding, or total days of bleeding (14.3 +/- 3.7 vs. 17.1 +/- 4.0, p = 0.62) during the three months interval following injection, compared with the standard second injection interval. Moreover, an excessive BMI gain (BMI increase 0.99 +/- 0.22 vs. 0.40 +/- 0.14, p = 0.03) was observed in these girls. Girls who switched directly from OCP showed no difference in the rate of BMI gain when compared to those not previously on OCP (BMI increase 0.38 +/- 0.3). Bleeding duration of these girls, however, was markedly reduced; the total number of days of bleeding was 5.7 +/- 1.9 (p = 0.0003) during the first three month interval, and 5.7 +/- 2.3 (p = 0.019) during the three month period following the second injection. This reduction did not persist beyond the first six months. CONCLUSIONS: Early second Depo-Provera injection does not alter the experience of menstrual abnormalities, and predisposes to greater weight gain; OCP use prior to Depo-Provera results in a decrease in the duration of bleeding with no change in the weight gain rate.

Adolescent↗
PubMed1995

Long-term alterations in growth hormone and insulin secretion after temporary dietary protein restriction in early life in the rat.

Protein malnutrition early in life stunts subsequent physical growth in both humans and rats, but the mechanism(s) is unknown. To test the hypothesis that temporary early life dietary protein restriction produces long-term alterations in the growth hormone (GH) neuroendocrine axis, we examined the effects of 3 wk of exposure to dietary protein restriction in male rats postweaning (3-6 wk of age) on spontaneous and GH-releasing factor (GRF)-stimulated GH secretion at 12 wk of age. In comparison to rats weaned onto a normal diet (23% protein), rats weaned onto a low (4%) protein diet failed to catch up growth when transferred to the normal diet between 6 and 12 wk of age. Spontaneous 6-h GH secretory profiles of adult rats fed the low protein diet early in life showed a 41% reduction in mean GH peak amplitude and a significant suppression in overall mean 6-h plasma GH concentrations (37.5 +/- 4.5 versus 56.9 +/- 5.9 micrograms/L; p < 0.02). The magnitude of the GH response to 1 microgram of rat GRF(1-29)NH2 i.v. challenge was augmented during the GH trough period in these rats (165.7 +/- 30.4 versus 43.9 +/- 17.6 micrograms/L; p < 0.01). Although basal plasma IGF-I levels and glucose tolerance of protein-deprived rats were normal at 12 wk of age, the insulin response to ip glucose was severely blunted [insulin integrated area under the curve: 303.0 +/- 32.7 versus 778.3 +/- 105.0 pmol/L/75 min; p < 0.01]. These results demonstrate that temporary protein malnutrition early in life 1) blunts spontaneous pulsatile GH secretion, 2) augments GH responsiveness to GRF challenge, and 3) reduces the insulin secretory response to glucose in adulthood. Our findings suggest that dietary protein in early life is an important determinant for CNS control of GH secretion as well as for the development of pancreatic beta-cell sensitivity to glucose. Such alterations in the GH neuroendocrine axis, together with the subnormal insulin secretion, likely contribute to the lack of catch-up growth in this model.

Animals↗