Estrogen replacement therapy

Estrogen stimulates adenosine receptor expression subtypes in human breast cancer MCF-7 cell line

Estrogen is a steroid hormone that plays a key role in the development and regulation of reproductive system. It has been shown that estrogen is related to breast cancer development through binding to its receptors. In order to uncover the estrogen effects on adenosine receptor expression, estrogen-positive MCF-7 cells were used to treat with agonist and antagonist of estrogen and then the mRNA expression of adenosine receptor subtypes were evaluated. Estrogen-positive MCF-7 cells were treated with various concentrations of 17β estradiol (E2) as an estrogen agonist, and ICI 182,780 as an estrogen antagonist. The gene expression of adenosine receptor subtypes were detected by real time RT-PCR. The results of MTT assay showed that E2 increased cell viability in a dose dependent manner. The expression pattern of all adenosine receptor subtypes are as follow; A2b > A1 > A2a > A3 in untreated MCF-7 cells. Obtained results showed that E2 incubation at 0.001-0.01 μM led to up-regulation of A1ARs, A2aARs and A3ARs dose dependently. E2 at 0.001 μM also had no significant effect on A2bARs expression but, at higher doses induced a considerable decrease in mRNA A2bARs expression. Treatment with antagonist confirmed that up-regulation of these receptors is mediated by estrogen receptor. Taken together, our results indicate that treatment of MCF-7 cells with E2 led to up-regulation of adenosine receptors. However, these effects were partially restored by treatment with antagonist suggesting that such effects are mediated by estrogen receptors.

SERUM LIPID PROFILE OF SPAYED AND NON-SPAYED FEMALE DOGS ASSOCIATED WITH THE BODY CONDITION SCORE

Neutering females may be associated to weight gain in dogs. In order to diagnose possible alterations, such as diabetes and hyperlipidemias, laboratory assessment of carbohydrate and lipid metabolism is important. The aim of this study was to verify glycemia and serum lipid profile in non-spayed and spayed female dogs, and associate these results with the body condition score. Thirty-two spayed (n=16) and non-spayed (n=16) female dogs had their blood collected for biochemical analysis, and were classified as to their body condition score (BCS). Nine had normal BCS, 10 were overweight, and 13 were obese. Little difference was observed among spayed and non-spayed dogs. Glycemia of spayed canine females is higher than that of non-spayed dogs, regardless of the body condition score. Likewise, total cholesterol levels are higher in non-spayed females. The HDL is higher in non-spayed obese dogs than in spayed dogs with the same body condition, this parameter did not differ in other weight groups. Contrary to what happens in post-menopausal women, spaying dogs does not seem to have such a strong effect on the metabolic parameters assessed. This study revealed unique results, where neither spaying nor weight group had a strong association with metabolic alterations.

Densidade mineral óssea em cadelas submetidas à ovarioisterectomia com e sem reposição estrogênica oral

Estudaram-se os efeitos da ovarioisterectomia na densidade mineral óssea de cadelas e da reposição de estrógenos após a cirurgia. Foram utilizadas 12 cadelas, sem raça definida, entre dois e seis anos de idade e pesos entre 5 e 15kg. Os animais, submetidos à ovarioisterectomia, foram separados em dois grupos de seis. Um grupo serviu como controle, e o outro recebeu estrógenos naturais conjugados na dose de 0,01mg/kg via oral a cada 48 horas, durante 12 meses. No dia da cirurgia e após 12 meses, foram feitas radiografias com vistas à densitometria óptica em imagem radiográfica. A ovarioisterectomia diminuiu a densidade óssea, e a reposição estrogênica, na dose utilizada, foi capaz de preservá-la.

Continuation rate of hormone replacement therapy in Hong Kong public health sector

OBJECTIVES

To assess the 1-year continuation rate of HRT prescribed in Hong Kong public health sector and to identify factors affecting this continuation rate.

METHODS

All women who received at least one dispensed prescription of estrogens between January 1998 and December 2000 from 36 specialist outpatient clinics of the Hospital Authority were selected, and observed for at least 2 years and at most 3 years. The duration of use and variables including age, types of hormones, routes of delivery, dose of estrogen, and prescribing specialty were retrieved from the central prescription database of the Hospital Authority.

RESULTS

Of 12,711 incident users of HRT, more than half were aged 50-59. Most (78.5%) of the users took conjugated equine estrogens (CEE) 0.625 mg or related products. Only a small proportion (3.0%) of women used CEE 0.3 mg. Initial estrogen prescriptions were written by gynaecologists in 86.7%. The overall 1-year continuation rate was 68.3%. The highest and lowest continuation rates were observed in women aged 40-49 and the two extreme age groups (35-39 and 70-79), respectively. Better continuation rate was observed in women taking estrogen-only therapy such as CEE or estradiol (overall 76.3%) than in women using continuous combined therapy (58.6%), sequential combined therapy (64.8%), or transdermal estrogen (60.6%). In the age group 60-69, the use of CEE 0.3 mg was associated with better continuation rate than CEE 0.625 mg.

CONCLUSIONS

Better continuation rate at 1 year was associated with age younger than 60, oral route of HRT and hysterectomy.

Perfil lipoprotéico de cadelas submetidas à ovário-histerectomia com e sem reposição estrogênica

Doze cadelas mestiças, adultas, foram submetidas à ovário-histerectomia e posteriormente distribuídas em dois grupos de seis animais. Um dos grupos recebeu estrógenos naturais conjugados na dose de 0,01mg/kg, via oral, a cada 48 horas, durante 12 meses, e o outro serviu como controle. A cada 60 dias foram realizadas colheitas de sangue e obtidos os valores de colesterol total, triglicerídeos, HDL, LDL e VLDL. Houve elevação do colesterol total e do LDL nas fêmeas sem reposição de hormônio. No grupo que recebeu estrógenos houve elevação do HDL. A ovário-histerectomia influenciou significativamente o perfil lipoprotéico; a reposição com estrógenos foi capaz de preservar esse perfil nas cadelas castradas.

Development of an immunosensor for human ferritin, a nonspecific tumor marker, based on surface plasmon resonance

A direct human ferritin immunosensor was developed using anti-human ferritin monoclonal antibodies (MAbs) immobilized on the gold surface of a self-assembled surface plasmon resonance (SPR) apparatus. A kind of self-assembled monolayer (SAM) prepared by cystamine-glutaraldehyde method was applied to immobilize the MAbs. The reusability of the sensor chip adopting the SAM was found to be better than the other immobilization methods including adsorption, protein A, concanavalin A method. Ten cycles of measurements could be performed on the same chip regenerated with a 0.1M HCl solution. A linear relationship existed between the angle shifts (millidegrees) and the log values of ferritin concentrations in the range from 0.2 to 200 ng/ml in buffer and human serum. When used for 15 days, the angle shifts were all >95% of those on the response at the first day. A 10 M NaOH solution was used for clearing nonspecific binding in human serum. Correlation coefficient was 0.991 between this SPR method and chemiluminescent immunoassay for determination of ferritin in clinical human serum samples. The SPR sensor offers advantages of simplicity of immobilization, high sensitivity, high specificity, low sample requirement, high reusability, no label and no pretreatment etc.

Early detection of genetic hemochromatosis: should all young adults be offered the genetic test?

Genetic hemochromatosis (GH) is a late-onset, autosomal recessive disorder. The majority of those at risk from iron overload and its clinical consequences may be detected by a simple genetic test. Furthermore, treatment by phlebotomy, if instituted early, removes excess iron and prevents the complications of iron overload which include arthralgia, diabetes, and cirrhosis of the liver. GH seems to be an obvious candidate for inclusion in national screening programs. However, important questions remain concerning the proportion of individuals with the high-risk genotype who eventually show clinical manifestations of iron overload and the significance of heterozygosity for haemochromatosis in terms of morbidity. Until these questions are resolved, the introduction of widespread genetic screening cannot be justified.

Monoclonal and polyclonal antibodies against human ferritin, a nonspecific tumor marker

The aim of this study was to produce monoclonal and polyclonal antibodies against a nonspecific tumor marker, human ferritin. Hyperimmune ICR mice produced polyclonal antibodies after injection with 0.5 mL pristane, and were injected with NS-1 myeloma cells 2 weeks later. Hyperimmune Balb/c mice were used for the production of monoclonal antibodies (MAbs). Mice were immunized four times, given a final boost, and their spleen cells were collected and fused with NS-1 myeloma cells under the presence of PEG 1500. The fused cells were then selected in the HAT-RPMIX medium. Anti-ferritin antibody-secreting hybridoma cell lines with high titer were cloned by enzyme-linked immunoadsorbent assay (ELISA) and then subcloned by limiting dilution in 15% fetal bovine serum (FBS) HT-RPMIX medium. Five murine hybridoma-producing antiferritin MAbs were obtained and designated 1AD11F9, 1AD11E11, 2AD11D2, 2AD11A5, and 3AD11G8. Isotypes of these MAbs were identified as IgM heavy chain and kappa light chain. Hitrap Protein A and Hitrap IgM purification column were used for the purification of polyclonal and monoclonal antibodies, respectively.

Preperitoneal fat thickness determined by ultrasonography is correlated with coronary stenosis and lipid disorders in non-obese male subjects

OBJECTIVE

To investigate the relationship between preperitoneal fat thickness (PFT) determined by ultrasonography and the risk of coronary arterial disease, 130 non-obese patients with ischemic heart disease (77 men and 53 women) were examined.

RESULTS

There was a positive correlation between PFT and coronary artery stenosis score (r = 0.212, P < 0.05). After dividing the patients by gender, the correlation was recognized only in men (r = 0.246, P< 0.05). Also, PFT was positively correlated to serum total cholesterol (r = 0.259, P < 0.01), triglyceride (r = 0.205, P < 0.05) and low density lipoprotein (LDL)-cholesterol (r = 0.205, P < 0.05), and negatively correlated to serum high density lipoprotein (HDL)-cholesterol (r = -0.261, P < 0.01). Again, these correlations were found only in men, not in women.

CONCLUSION

PFT shows good correlations with coronary artery stenosis score and dyslipidemia, and may lead to the development of coronary artery disease in non-obese male subjects.

Is physical activity as effective in reducing risk of cardiovascular disease as estrogen replacement therapy in postmenopausal women?

Coronary heart disease (CHD) is known as a disease of postmenopausal women. While hormone replacement therapy is recommended increasingly to postmenopausal women for the prevention of CHD, the potential impact of non-pharmacologic interventions on cardiovascular disease reduction has been largely unexplored. The purpose of this article is to develop the understanding of the research literature on three risk factors by which estrogen and physical activity, a non-pharmacologic intervention, may confer cardiovascular protection in postmenopausal women. Three risk factors are lipoproteins, systolic pressure, and changes in the vascular endothelial functions. Effects of estrogen and physical activity on these biological factors are compared.

Individual and combined effects of estrogen/progestin therapy and lovastatin on lipids and flow-mediated vasodilation in postmenopausal women with coronary artery disease

OBJECTIVES

We sought to examine the individual and combined effects of estrogen/progestin therapy versus lovastatin on lipids and flow-mediated vasodilation in postmenopausal women with heart disease.

BACKGROUND

Little information is available regarding the relative benefits of estrogen replacement therapy versus reductase inhibitors and the potential utility of their combination as lipid-lowering therapy for postmenopausal women.

METHODS

We conducted a randomized, double-blind, crossover trial in 24 postmenopausal women, each of whom received the following drug regimens during three consecutive six-week treatment periods: 1) hormone replacement (oral dose of 0.625 mg/day conjugated equine estrogens and 2.5 mg/day medroxyprogesterone acetate); 2) 20 mg lovastatin/day and 3) hormone replacement plus lovastatin.

RESULTS

Total and low density lipoprotein (LDL) cholesterol were significantly lowered and high density lipoprotein (HDL) cholesterol was significantly increased by all three regimens compared with baseline (p < 0.05). Lovastatin was more effective than estrogen/progestin in reducing LDL (p < 0.001), but estrogen/progestin was slightly more effective in increasing HDL. The hormone replacement and lovastatin regimen blocked the estrogen-associated increase in triglycerides. Hormone replacement (alone and with lovastatin) resulted in increases in brachial artery flow-mediated vasodilator capacity (p = 0.01 for both regimens) and the area under the curve (p = 0.016 and p = 0.005, respectively) compared with baseline. Percent dilation was greatest after the hormone replacement regimen, whereas the area under the curve was greatest after hormone replacement plus lovastatin (69% improvement vs. baseline).

CONCLUSIONS

In postmenopausal women with coronary disease and hyperlipidemia, conjugated equine estrogen produced significant improvements in lipids and vasodilator responses despite the concurrent administration of low dose medroxyprogesterone acetate. Low dose lovastatin produced greater reductions in LDL, but less dramatic improvements in vasodilator responses. Estrogen/progestin plus lovastatin may provide additional benefits via a greater reduction in the LDL/HDL ratio and attenuation of estrogen-associated hypertriglyceridemia. More information is needed about the safety and efficacy of such combinations of hormone replacement and reductase inhibitor therapy.