La lactancia prolongada se relaciona con menores niveles de leptina en pacientes con diabetes mellitus gestacional / Duration of lactation is associated with lower leptin levels in patients with gestational diabetes mellitus

Las mujeres con diabetes mellitus gestacional (DBTG) tienen un riesgo elevado de presentar diabetes tipo 2 en el posparto. La lactancia materna se ha asociado con una disminución del riesgo de diversas enfermedades metabólicas. El objetivo de este estudio fue evaluar el impacto de la duración de la lactancia sobre niveles de leptina en mujeres con DBTG previa, en comparación con mujeres con embarazo normal. Materiales y métodos: Se realizó un análisis secundario a una base de datos de un estudio prospectivo comparativo en el que se evaluaron en el embarazo y el posparto 43 mujeres con DBTG y 43 embarazadas normotensas euglucémicas. Se clasificó a las participantes de acuerdo con el tiempo de lactancia materna en duración breve (menos de 6 semanas) o duración prolongada (más de 6 semanas a menos de 6 meses) y se determinaron sus niveles de leptina. Resultados: Las mujeres con DBTG que tuvieron una lactancia de duración prolongada presentaron una mayor disminución de peso en el posparto y un menor nivel de leptina, en comparación con las de lactancia materna de duración breve. Esta diferencia permaneció estadísticamente significativa después del ajuste por el peso de las participantes. En el grupo de control, las mujeres con lactancia de duración prolongada presentaron menores niveles de triglicéridos, insulina y resistencia a la insulina. Conclusiones: La duración prolongada de la lactancia se asoció con menores niveles de leptina y con mejor perfil metabólico en el período posparto temprano de las mujeres con DBTG previa y con embarazo normal, respectivamente...

Relationship between circulating adipokines and insulin resistance during pregnancy and postpartum in women with gestational diabetes.

BACKGROUND AND AIMS: We undertook this study to assess the relationship between circulating adipokines and insulin resistance during pregnancy and postpartum in women with gestational diabetes mellitus (GDM). METHODS: This was a prospective study including 60 women with GDM and 60 subjects with normal gestation who were evaluated at gestational week 30, 6 weeks and 6 months postpartum. Circulating adipokines that were evaluated during the study were leptin, adiponectin, retinol-binding protein-4 (RBP4), and tumor necrosis factor-alpha (TNF-α). RESULTS: Women with GDM showed higher insulin resistance measured by HOMA-IR than subjects with normal gestation (2.3 ± 2.3 vs. 1.3 ± 0.95). There was no difference between groups in adipokines; however, in women with a healthy pregnancy, RBP4 was associated with insulin resistance (r = 0.47, p <0.05). At 6 weeks and 6 months postpartum, women with previous GDM exhibited persistent elevated leptin and insulin resistance. RBP4 was associated with insulin resistance only in women with a previous healthy pregnancy (r = 0.51, p <0.05). In addition, progressively impaired glucose tolerance was observed after delivery in women with previous GDM. CONCLUSIONS: It was demonstrated that GDM is associated with greater insulin resistance than observed in normal pregnancy; however, adipokines are similar in both groups. RBP4 levels are significantly associated with insulin resistance in healthy women during pregnancy and postpartum. After a pregnancy complicated by GDM, leptin and insulin resistance remain elevated and glucose tolerance worsens.

[Relationship between sex steroids and bone density in elderly men]. / Relación entre esteroides sexuales y densidad ósea en el hombre senescente.

OBJECTIVE: To determine the relationship between serum estradiol level (ESL) and testosterone serum level (TSL) with bone mineral density (BMD) in elderly men. METHODS: Cross-sectional study including 127 healthy men aged 60 years and over. BMD of the lumbar spine and femoral neck were measured. ESL, TSL and sex hormone binding globulin were estimated by radioimmunoassay. Free testosterone level (FTL) was calculated. RESULTS: The ESL and BMD correlation at the spine was r = 0.288, (p < 0.01) and at the femoral neck was r = 0.224, (p < 0.01). These correlations remained significant after adjustment for BMI and age. By contrast, no correlation was found between TSL and BMD. However FTL were associated with BMD at the spine (r = 0.288, p < 0.01) and at the femoral neck (r = 0.190, p < 0.05). CONCLUSIONS: ESL and FTL are associated with BMD in elderly men. This effect may be partially mediated by the peripheral conversion of testosterone into estradiol.

[Efficacy of strontium ranelate for the mineralization of bone in postmenopausal women]. / Eficacia del ranelato de estroncio para la mineralización ósea en mujeres posmenopáusicas.

INTRODUCTION: Osteoporosis is the most common skeletal disorder and is considered a risk of fracture. Most medication used for the treatment of osteoporosis are antiresorptive; however strontium therapy in postmenopausal women has shown a double effect on resorption and bone formation. OBJECTIVE: To evaluate the effect of strontium on bone mineral density (BMD) and circulating biochemical markers of bone turnover in postmenopausal women who had a decreased BMD. MATERIAL AND METHODS: A prospective study was carried out in 23 postmenopausal women who had decreased BMD, who received daily strontium orally by night during 12 months. Evaluation of BMD at lumbar spine and hip as well as biochemical markers in blood for bone turnover before and during therapy. RESULTS: BMD at the spine (0.755 +/- 0.104 to 0.792 +/- 0.094, p < 0.05) and hip (0.833 +/- 0.096 to 0.856 +/- 0.100, p < 0.05) increased significantly after 12 months of treatment. Bone turnover markers showed a decrement of osteocalcin, by contrast the specific alkaline phosphatase increased after 6 months of therapy; however C-terminal telopeptide of type 1 collagen was not modified. CONCLUSIONS: Strontium ranelate increased significantly BMD at the spine and at the hip in postmenopausal women and simultaneously improved bone turnover estimated by circulating bone markers.

Adiponectin is associated with low bone mineral density in elderly men.

OBJECTIVE: Recent evidence suggests that adiponectin may play a role in bone metabolism. Previous studies demonstrated that the adiponectin levels had a negative correlation with bone mineral density (BMD) in women. However, little is known about the relationship between adiponectin and BMD in men. The aim of this study was to determinate the relationship between the adiponectin levels and BMD in elderly men. DESIGN: Cross-sectional study including 92 healthy men aged 60-80 years. METHODS: Main outcome measures were the adiponectin levels estimated by RIA and BMD at lumbar spine and femoral neck using dual energy X-ray absorptiometry. Results The negative correlation between adiponectin and BMD at the spine was r=-0.209, (P<0.05) and at the femoral neck was r=-0.237, (P<0.001). These correlations disappeared after adjustment for body mass index (BMI). When stratified by BMI, the relationship between BMD and adiponectin remained significant in the subgroup of participants with BMI >27 kg/m(2), but disappeared in men with BMI 27. CONCLUSION: BMD is negatively associated with the adiponectin levels in men older than 60 years and this relationship is greater in those men with BMI >27, which suggests a plausible connection between bone and fat tissue.

Effect of testosterone therapy on lumbar spine and hip mineral density in elderly men.

OBJECTIVE: The aim of the present study was to analyse the effect of testosterone therapy on bone mineral density in healthy elderly men who had low levels of total testosterone. DESIGN: Randomized, double-blind, placebo-controlled study. PARTICIPANTS: Forty-eight men over 60 years old with decreased testosterone levels (< or =320 ng/dL) comprised the study. Twenty-five out of 48 received intramuscular injections of testosterone enanthate every three weeks during 12 months; the remaining 23 participants formed the control group. All participants had measurements of bone mineral density (BMD) in both lumbar spine and hip before and at the end of the study as well as testosterone and 17-beta estradiol levels. RESULTS: Testosterone treated group exhibited a significant (p < 0.05) increment (from 1.198 +/- 0.153 to 1.240 +/- 0.141 g/cm(2)) in lumbar BMD in parallel with a significant (p < 0.001) increment (from 301 +/- 32 to 471 +/- 107 ng/dL) in testosterone concentrations, whereas no significant change occurred in femoral neck BMD. CONCLUSIONS: Testosterone therapy elicited a positive effect only in lumbar BMD in elderly men with diminished testosterone serum levels.

[Adiponectin levels in perimenopause]. / Concentración de la adiponectina en perimenopáusicas.

BACKGROUND: Adiponectin is an hormone produced exclusively in adipose tissue, that actively acts in carbohydrate and fat regulation processes. OBJECTIVE: To determine adiponectin levels in a women's group. PATIENTS AND METHOD: Transversal study in 22 amenorrheal women with climacteric symptoms, and without estrogen therapy. There were excluded those with diabetes, hypertension, dislipoproteinemia and obesity. Significant differences among values of adiponectin in perimenopausal and young women during follicular phase of menstrual cycle were analyzed by means of Student t test. RESULTS: Adiponectin concentration in perimenopausal women was 14.1 +/- 8.2 microg/mL (M +/- SD), without meaningful difference compared with young women. CONCLUSIONS: It wasn't significant variation in adiponectin levels compared with normal menstrual cycle women. Further studies are necessary to establish adiponectin effect in postmenopause and its relation with the cardiovascular diseases.

Role versatility among men who have sex with men in urban Peru.

Role versatility refers to the practice in which individual men who have sex with men (MSM) play both insertive and receptive sexual roles over time. Versatility has been thought to be relatively uncommon among Latin American MSM but possibly rising. Versatility has also been shown to be a potentially large population-level risk factor for HIV infection. In this study we examine the correlates of versatile behavior and identity among 2,655 MSM in six Peruvian cities. Versatile behavior with recent male partners was found in 9% of men and versatile ("moderno") identity was reported by 16%. Significant predictors included high education, white-collar occupation, sex work, and residence in Lima. Age was not significant in any analysis. Since sex work is negatively correlated with other predictors, versatile men appear to comprise two distinct sub-populations. Insertive-only men appear to play a strong role in bridging the HIV epidemic between MSM and women.

Effect of estrogen therapy on insulin resistance and plasminogen activator inhibitor type 1 concentrations in postmenopausal women.

BACKGROUND/AIMS: An elevated thrombotic risk due to abnormal fibrinolysis might be associated with insulin resistance in postmenopause. The aim of this study was to investigate the association of insulin resistance with a biochemical marker of fibrinolysis as well as the effect of transdermal estrogen treatment (ET) on this association. METHODS: Thirty postmenopausal hysterectomized women received transdermal estradiol during 3 months. 17Beta-estradiol, FSH, LH, plasminogen activator inhibitor type 1 (PAI-1), insulin and glucose were measured in blood samples before and after ET. Insulin resistance was calculated by the use of the homeostasis model assessment for insulin resistance (HOMA-IR). RESULTS: ET induced a significant decrement in both PAI-1 levels and HOMA-IR values. The study also showed that HOMA-IR was a significant predictor for PAI-1 concentrations. CONCLUSION: Short-term ET improved HOMA-IR values in parallel with a decrease in PAI-1 levels.

[Adiponectin concentrations during menstrual cycle]. / Variación de adiponectina en el ciclo menstrual.

BACKGROUND: Adiponectin has a direct relationship with cellular sensibility grade to insulin action. OBJECTIVE: To determine adiponectin concentrations during the three phases of the menstrual cycle in young women, and to study the relationship with 17-beta estradiol and progesterone levels. PATIENT AND METHODS: Longitudinal and prospective study that included 30 normal menstruating women aged between 19 and 36 years; none had received any hormonal therapy prior to this study. Adiponectin, 17-beta estradiol, progesterone, LH and FSH were determined in blood in three phases of one menstrual cycle for each participant. RESULTS: Adiponectin concentrations were lower in the postovulatory phase as compared with the other two phases. Adiponectin levels did not significantly correlate with 17-beta estradiol and progesterone. CONCLUSION: Adiponectin blood levels are variable during the menstrual cycle, but the lower concentrations are observed in the postovulatory period that could be associated with other metabolic processes, such as insulin resistance.

[Oral or trandsdermanl hormone replacement therapy reduces interleukine-6 levels]. / La terapia estrogénica de reemplazo, oral o transdérmica, reduce las concentraciones de interleucina-6.

OBJECTIVE: To compare the effect of oral and transdermal estrogen replacement therapy (ET) on circulating interleukin-6 (IL-6) in post-menopausal women. PATIENTS AND METHOD: Prospective open trial study in 55 healthy hysterectomized postmenopausal women with a mean age of 52 years. Twenty-seven women received oral conjugated equine estrogens (0.625 mg daily) and the remaining 28 received transdermal estrogen replacement therapy (50 microg/day) during 6 months. At baseline both groups were similar as to age, body weight, and body mass index as well as serum levels of LH, FSH, 17-beta estradiol (E2) and IL-6. RESULTS: Baseline elevated IL-6 levels decreased significantly (p<0.05) after both oral and transdermal estrogen replacement therapy; this decrement showed no difference between the two groups. After the follow-up there were no differences in body weight and body mass index between groups; however, in the oral group there was a trend to increment this parameters. Serum levels of E2 and IL-6 were negatively correlated in the two groups and IL-6 was positively correlated with body mass index in untreated women and this correlation was the same in women with estrogen replacement therapy. CONCLUSIONS: The decrement of IL-6 after estrogen replacement therapy was similar for both routes of administration; in addition IL-6 had a negative correlation with E2 and a positive correlation with body mass index.

Glucose-6-phosphate dehydrogenase activity and NADPH/NADP+ ratio in liver and pancreas are dependent on the severity of hyperglycemia in rat.

Hyperglycemia is associated with metabolic disturbances affecting cell redox potential, particularly the NADPH/NADP+ ratio and reduced glutathione levels. Under oxidative stress, the NADPH supply for reduced glutathione regeneration is dependent on glucose-6-phosphate dehydrogenase. We assessed the effect of different hyperglycemic conditions on enzymatic activities involved in glutathione regeneration (glucose-6-phosphate dehydrogenase and glutathione reductase), NADP(H) and reduced glutathione concentrations in order to analyze the relative role of these enzymes in the control of glutathione restoration. Male Sprague-Dawley rats with mild, moderate and severe hyperglycemia were obtained using different regimens of streptozotocin and nicotinamide. Fifteen days after treatment, rats were killed and enzymatic activities, NADP(H) and reduced glutathione were measured in liver and pancreas. Severe hyperglycemia was associated with decreased body weight, plasma insulin, glucose-6-phosphate dehydrogenase activity, NADPH/NADP+ ratio and glutathione levels in the liver and pancreas, and enhanced NADP+ and glutathione reductase activity in the liver. Moderate hyperglycemia caused similar changes, although body weight and liver NADP+ concentration were not affected and pancreatic glutathione reductase activity decreased. Mild hyperglycemia was associated with a reduction in pancreatic glucose-6-phosphate dehydrogenase activity. Glucose-6-phosphate dehydrogenase, NADPH/NADP+ ratio and glutathione level, vary inversely in relation to blood glucose concentrations, whereas liver glutathione reductase was enhanced during severe hyperglycemia. We conclude that glucose-6-phosphate dehydrogenase and NADPH/NADP+ were highly sensitive to low levels of hyperglycemia. NADPH/NADP+ is regulated by glucose-6-phosphate dehydrogenase in the liver and pancreas, whereas levels of reduced glutathione are mainly dependent on the NADPH supply.

Expression of growth hormone receptor isoform exon-3-excluding and exon-3-retaining messenger RNAs in peripheral lymphocytes from normal and acromegalic subjects.

AIM: To determine the expression of two isoforms of the growth hormone (GH) receptor (GHR), which differ by the presence (GHR3+) or absence (GHR3-) of exon 3, and their correlation with circulating GH and insulin-like growth factor I (IGF-I) in normal subjects and in acromegalic patients. METHODS: The expression of GHR isoforms was determined by reverse-transcriptase polymerase chain reaction in lymphocytes from 12 normal subjects and from 11 patients with acromegaly. The levels of GHR mRNA were normalized to those of beta-actin, and ratios were calculated to assess the relative levels of expression. RESULTS: All samples showed expression of both GHR isoforms, but the expression of GHR3+ and GHR3- was similar in acromegalic patients (6.0+/-1.7 vs. 8.3+/-2.0%, mean +/- SE). In contrast, in healthy subjects, GHR3- was the predominant isoform (11.8+/-3.0 vs. 5.1+/-0.68%; p<0.05), and the levels of expression of GHR3- correlated significantly with IGF-I. CONCLUSIONS: These data demonstrate coexpression of both GHR isoforms under normal and pathological conditions; however, GHR3- is the predominant form in normal subjects and shows a negative correlation with IGF-I levels.

Pilot study of COBAS PCR and ligase chain reaction for detection of rectal infections due to Chlamydia trachomatis.

We tested rectal specimens from men who have sex with men for Chlamydia trachomatis by using COBAS PCR (Roche Diagnostics) and ligase chain reaction LCR (Abbott laboratories) and compared three PCR specimen-processing procedures. Chlamydiae were detected by one or more procedures in 22 of 186 specimens. All three PCR tests were positive for 17 specimens, all of which also tested positive by LCR.

Correction of insulin resistance in methimazole-treated patients with graves disease / Corrección de la resistencia a la insulina en pacientes con enfermedades de Graves tratados con metimazol

Durante muchos años el efecto del hipertiroidismo sobre la tolerancia a la glucosa, así como sobre la secreción de la insulina y su acción periférica han sido motivos de debate. El hipertiroidismo por enfermedad de Graves se ha relacionado con intolerancia a la glucosa y resistencia a la insulina. El objetivo del presente estudio fue determinar en pacientes con hipertiroidismo, el efecto del tratamiento con metimazol sobre la sensibilidad a la insulina, utilizando la técnica de la pinza hiperinsulinémica euglicémica. Después de cuatro meses de tratamiento, los pacientes se encontraban controlados en eutiroidismo y la sensibilidad a la insulina incrementó de 3.47 a 6.39 mg/kg/min (p<0.05); de lo anterior se concluye que la resistencia a la insulina mejora con el tratamiento exitoso del hipertiroidismo. El mecanismo preciso por lo el que un exceso de hormonas tiroideas deteriora la sensibilidad a la insulina aún no se encuentra completamente aclarado.

La leptina circulante no se modifica en mujeres posmenopáusicas que reciben terapia de reemplazo con tibolona / Circulating leptine does not increase in postmenopasual women receiving tibolone as replacement therapy

Durante la etapa posmenopáusica, la reducción de leptina circulante se ha relacionado con el incremento de peso corporal; sin embargo los resultados de los diferentes estudios han sido contradictorios y sólo se ha encontrado un incremento leve de la leptina con la terapia hormonal de reemplazo (THR). En este trabajo se hipotetizó que las concentraciones de leptina no estaban relacionadas con el hipoestrogenismo y que no se incrementaban por la THR. Para probar nuestra hipótesis se estudiaron 22 casos consecutivos de mujeres en etapa posmenopáusica, de 46 a 60 años de edad, que habían tomado al menos por 12 meses 2.5 mg diarios de tibolona. Otras 12 mujeres posmenopáusicas, agrupadas por edad y peso, sin THR, se utilizaron como grupo control. No se observaron diferencias significativas en las concentraciones de leptina entre las mujeres que estaban bajo la administración de tibolona (8.1 ñ 4.2ng/mL) y el grupo control (7.4 ñ 3.7 ng/mL). Las pacientes tratadas con tibolona presentaron disminución significativa de los niveles de insulina e incremento de IGF-l en comparación con el grupo testigo. De estos datos se puede concluir que la THR con tibolona no produce un incremento en la leptina circulante en mujeres menopáusicas, por lo que es probable que los niveles de leptina no ejerzan efecto sobre el peso corporal.

Evaluation of an immunoenzymometric assay (IEMA) using automated system for determination of luteinizing hormone and follicle stimulating hormone

It has been proposed that automated systems for immunoenxymometric assay (IEMA) may substitute traditional radioimmunoassay (RIA) for measurement of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in blood due to the advantage of being more rapid, higher sensitivity, lower cost and not requiring radioactive reagents. The study was designed to evaluate both systems using serum samples to determine luteinizing hormone (LH) and follicle stimulatin hormone (FSH) concnetrations. The automatic system (ES-300) for IEMA utilized two monoclonal antibodies, one of them on the solid phase was the specific extractant for the antigen, and the other was a peroxidase labeled antibody which recognizes a different epitope in the antigen molecule, specifically bound in linear proportion to the antigen concentration. Blood samples were obtained from patients who were treated at the hospital for various clinical problems ("problem group") as well as blood samples from patients in whom FSH and LH concentrations were already known ("high", "medium" and "low" levels) by previous RIA ("control group"). IEMA showed a higher sensitivity, 0.42 and 0.96 mIU/ml for FSH and LH, respectively, whereas RIA was 1.95 mIU/ml for both hormones. Intra and interassay coefficient of variation were below 10 percent within the range of 15-50 mIU/ml for FSH and 5-100 mIU for LH; however, the coeffcient of variation was 15 - 25 percent at lower concentrations of FSH and LH. Accuracy of IEMA was evaluated by recovery percentage, thus when high and medium concentrations of FSH and LH were analyzed the recovery was between 99 -104 percent. On the other hand, the recovery was 100 percent when low levels of FSH and LH were used. In coclusion, IEMA resulted reliale when FSH and LH concentrations are in the middle and high range; likewise, the detection limit of IEMA was lower than RIA, particularly for FSH. On the bases of these results, IEMA showed several advantages over RIA, but its reliability diminishes when serum samples contain low FSH and LH concentrations. It is important to extend theses studies to steroid assays and elaborate a database in each laboratory