Effects of pacing-induced myocardial stress and spinal cord stimulation on whole body and cardiac norepinephrine spillover

AIMS: Spinal cord stimulation has been used in the treatment of intractable angina pectoris since the beginning of the 1980s. This study was designed to investigate whether the documented anti-ischaemic effects of spinal cord stimulation are mediated through a decrease in sympathetic activity. METHODS AND RESULTS: Ten patients with a spinal cord stimulator implanted as anti-anginal treatment were included in the study. Atrial pacing until the patient experienced moderate angina was performed and after 50 min rest the procedure was repeated during spinal cord stimulation. Total body and cardiac norepinephrine spillover was calculated and the former was found to have increased during pacing (47%, P = 0.02). When spinal cord stimulation was applied, total body norepinephrine spillover decreased at a comparable pacing rate (18%, P = 0.02). Cardiac norepinephrine spillover was not affected during the procedure. CONCLUSION: The results of this study indicate that the anti-ischaemic effect of spinal cord stimulation is not due to reduced cardiac sympathetic activity. However, spinal cord stimulation decreases overall sympathetic activity which may benefit the heart, possibly by reducing oxygen demand.     

Fertility in perimenopausal women

This study evaluated the effects of recombinant bovine somatotropin (bST; one injection of 320 mg per ewe) on milk production and composition and on the grazing behavior of multiparous ewes in the third to fourth lactation. Forty Comisana lactating ewes were divided into four groups: 1) untreated, grazing on natural pasture (botanical composition: 35% of Graminaceae, 49% of Fabaceae, 6% of Cruciferae, 10% of other families) at a low stocking rate (16 m2/d); 2) untreated, grazing at a high stocking rate (8 m2/d); 3) treated with bST, grazing at a low stocking rate; and 4) treated with bST, grazing at a high stocking rate. The diets of the ewes were supplemented with vetch and oat hay (500 g/d) and with concentrate (500 g/d). Treatment increased milk production (923.8 vs. 669.5 g/d) but had little effect on fat and protein contents. Administration of bST significantly increased herbage intake; the effect on intake was more marked at the high stocking rate. Under these grazing conditions, the treated ewes reduced selective intake behavior and, thus, achieved good feed intake despite the low biomass availability.     

Estrogen metabolism and excretion in Oriental and Caucasian women

BACKGROUND: Caucasian and Oriental women have different incidence rates of breast cancer. Among the underlying risk factors for the development of breast cancer in the women of these two groups may be their different diets and patterns of estrogen metabolism and excretion. The absolute levels and relative ratios of 16 alpha-hydroxylated estrogens and 2-hydroxylated estrogens (catechol estrogens) in the body may have a role in the etiology of breast cancer, but studies so far have provided only conflicting results. PURPOSE: Our goal was to study estrogen metabolism, in particular, the extent of 2-hydroxylation and 16 alpha-hydroxylation of estrogens in two groups of women, one Caucasian and one Oriental, with inherently different breast cancer risks. METHODS: Dietary records were analyzed over 3-day periods in the mid-follicular phase, twice, at 6-month intervals for 13 premenopausal Oriental women, recent immigrant arrivals in Hawaii with presumed low risk of breast cancer, and for 12 premenopausal Finnish women with presumed higher risk. The urinary estrogen profile was measured by gas chromatography-mass spectrometry and plasma and fecal estrogens were assayed by chromatographic radioimmunoassays. RESULTS: Mean fat intake per 1000 kcal was 73% higher (P < .001) in the Finnish women, but the mean fiber intake and fecal weights were similar to those of the Oriental women. Compared with Oriental women, Finnish women had 46% higher plasma estradiol (P < .01) and 124% higher plasma estrone sulfate (P < .01); however, after adjustment for differences in age and body mass index, only the difference in estrone sulfate remained statistically significant (P < .05). Mean plasma levels of estrone and estradiol correlated with height after adjustment for body mass index (P < .05). Mean plasma levels of estrone and sex hormone-binding globulin were similar. The Finns had higher mean urinary estrone (193%), estradiol (166%), various catechol estrogens (130%-439%), and total estrogen excretion (123%) (all P < .001), but similar 16 alpha-hydroxylated estrogen excretion. As calculated, 16 alpha-hydroxylation of estrone was significantly increased (P < .01) in the Oriental women, but 2-hydroxylation, 4-hydroxylation, and 16 beta-hydroxylation of estrone were similar in both groups. The ratio of catechol estrogen to 16 alpha-hydroxylated estrogen was four to five times higher (P < .001) in the Finnish women. The Oriental women had two to three times higher fecal excretion of estrogens than the Finnish women (P < .01). CONCLUSIONS: Our results indicate that high catechol estrogen formation may be a greater risk factor for breast cancer than high 16 alpha-hydroxylation of estrogens. However, the main risk factor for the Finnish women, as opposed to the Oriental women, may be their higher estrogen levels that result from a higher fat diet, higher estrogen production related to their greater height, and lower fecal estrogen excretion.     

Incidence of ovulation in perimenopausal women before and during hormone replacement therapy

Once hormone replacement therapy (HRT) has been commenced, it becomes extremely difficult to advise women approaching the menopause on the need for contraception. In this study of twenty women, neither the regularity of their pre-existing menstrual cycle nor a random FSH concentration predicted the likelihood of subsequent ovulation whilst taking HRT. HRT is not reliably contraceptive and women commencing HRT whilst still menstruating spontaneously must be advised on the need for additional contraception.     

Central DSP-4 treatment decreases norepinephrine levels and courtship behavior in male zebra finches

In zebra finches, gonadal steroids activate male courtship, including singing, and also strongly modulate norepinephrine (NE) levels and turnover in brain areas regulating courtship behavior. In a previous study, systemic administration of DSP-4 caused significant decreases in courtship singing. These behavioral decrements were correlated with the degree of NE depletion in several vocal control nuclei. In the present study, we attempted to further decrease brain NE levels while minimizing systemic effects by infusing DSP-4 directly into the third ventricle. DSP-4 treatment significantly reduced NE levels in three of six vocal control nuclei and both hypothalamic nuclei sampled without significantly altering dopamine or serotonin levels in any areas. DSP-4-treated males took longer to begin singing and performed fewer song bouts and courtship displays. Interestingly, behavioral deficits were limited to courtship song displays, other behavior patterns, including female-directed behaviors like approach and follow, were unaffected by DSP-4 treatment. DSP-4 treatment appeared to affect singing behavior by causing deficits in initial attentiveness to females and initiation of singing rather than by affecting song structure.     

Estrogen replacement in women treated for breast cancer

Oestrogen replacement therapy in women with a history of breast cancer has long been considered contraindicated. However, the literature does not indicate an increased risk of recurrent breast cancer in postmenopausal women receiving oestrogen replacement therapy. We advocate that women with a history of breast cancer without nodal involvement could be offered oestrogen replacement therapy and thereby benefit from prevention of cardiovascular disease and osteoporosis. But the patients must accept a potentially increased risk of recurrence. We emphasize the need for randomized prospective studies.     

Reproductive and menstrual factors in relation to mammographic parenchymal patterns among perimenopausal women

The relationship between mammographic patterns and reproductive and menstrual factors was examined in 3640 Norwegian women, aged 40-56 years, participating in the Third Troms? study conducted in 1986-87. Epidemiological data were obtained from questionnaires. The mammograms were categorised into five groups. This categorisation is based on anatomic-mammographic correlations, following three-dimensional (thick slice technique) histopathologic-mammographic comparisons, rather than simple pattern reading. Patterns 1-3 were combined into a low-risk group and patterns 4 and 5 into a high-risk group for analysis. Women who had more than four children were 90% less likely to have a high-risk pattern than nulliparous women (OR = 0.09, 95% CI 0.04-0.16) controlling for age, weight, height and menopausal status. Furthermore, those who first gave birth over 34 years of age were more than twice as likely to have a high-risk pattern than those giving birth in their teens (OR = 2.37, 95% CI 1.23-4.56) adjusting for parity. Among post-menopausal women, age at menarche was negatively (P for trend = 0.015) and late age at menopause positively (P for trend = 0.072) related to high-risk patterns. Among premenopausal women, age at menarche was positively related to high-risk patterns (P for trend = 0.001). Also, menopausal status rather than age was associated with high-risk patterns. These findings support the opinion that reproductive and menstrual factors are involved in determining the mammographic parenchymal pattern among perimenopausal women.     

Caffeine and other predictors of bone density among pre- and perimenopausal women

Cryopreservation has proved to be a highly successful method for long-term storage of viable embryos. The objective of this study on rat blastocysts was to define conditions for their cryopreservation. Three cryoprotectants, dimethyl sulfoxide, glycerol, and propanediol/sucrose, were compared in two cooling programs (to -30 or -80 degrees C) and two thawing protocols. The cooling was followed by immersion in liquid nitrogen. Programmed thawing was at the rate of 8 degrees C per minute; fast thawing consisted of direct exposure of the frozen embryos to the ambient laboratory temperature. The survival after the freeze/thaw was assessed from the post-thaw embryo morphology and ability to develop into apparently normal offspring in uteri of foster mothers (embryonic survival). The best method for preservation of rat blastocysts proved to be programmed cooling to -80 degrees C followed by fast thawing with glycerol as cryoprotectant (embryonic survival of 28.1%). In all the experimental groups, the proportion of embryos with good to excellent preservation of morphology was high. With dimethyl sulfoxide, after programmed cooling to -80 degrees C, embryonic survival was 9.9% (programmed thawing) and 17.5% (fast thawing). No embryos survived after programmed cooling to -30 degrees C. However, when the cryoprotectant was propanediol/sucrose, no difference was observed between programmed cooling to -80 degrees C with either method of thawing and programmed cooling to -30 degrees C and fast thawing (12.3, 6.2, and 8.0%, respectively).     

Changes in urinary excretion of type-I collagen cross-linked C-telopeptide and N-telopeptide in perimenopausal women

PURPOSE: The overall goal was to develop a simple test of random dot stereoacuity that can be used during the first 24 months of life to measure sensory outcomes following treatment of ophthalmopediatric disorders, both in the context of clinical trials and in the context of clinical management. METHODS: A series of random dot stereoacuity test cards were constructed using vectographic vertical bar stimuli with crossed disparities ranging from 1735 to 45 sec. A two-alternative, forced-choice, preferential-looking test protocol was used to measure stereoacuity in 95 healthy term infants (173 tests) over the 1.5-to-24-month age range. Success rate, validity, and tolerance limits for normal performance as a function of age were evaluated. RESULTS: The success rate was high (158 of 173 tests; 91.3%). The maturation of random dot stereoacuity was similar to that measured in earlier lab-based preferential-looking and visual evoked potential protocols; few infants younger than 2 months of age demonstrated stereopsis although by 12 months, mean stereoacuity was 2.1 log sec (120 sec). A further improvement to 1.7 log sec (56 sec) was seen during months 18 to 24, consistent with data obtained in an earlier operant random dot protocol. Tolerance limits for normal ranged from approximately 1000 sec at 6 months to 100 sec after 12 months. CONCLUSIONS: The infant random dot stereoacuity cards provide a simple, quick, and portable preferential-looking test of random dot stereoacuity for infants that has a high success rate and excellent concordance with stereoacuity outcomes from laboratory-based protocols.     

Estrogen absorption and metabolism in postmenopausal women with end-stage renal disease

Women with end-stage renal disease (ESRD) have a higher rate of death from heart disease than women with normal renal function. Because estrogen replacement therapy may significantly decrease the incidence of death due to cardiovascular disease in postmenopausal women with normal renal function, their use has been considered for women with ESRD. However, the pharmacokinetics of estrogen have not been studied in postmenopausal women with ESRD to determine the optimal estrogen dose. Six postmenopausal women with ESRD receiving maintenance hemodialysis and six controls matched for body mass index were admitted to the in-patient Clinical Research Center. A 1- or 2-mg oral estradiol (E2) pill was given while subjects fasted. Blood sampling was performed over the next 24 h for measurement of E2, estrone (E1), albumin, and sex hormone-binding globulin (SHBG). Three weeks later, the subjects were given the other E2 dose under identical conditions. At baseline, total and free E2 levels were higher in the subjects with ESRD than in controls (P = 0.0005 and 0.0035, respectively). After ingestion of 1 and 2 mg E2, total and free E2 levels remained significantly higher in the ESRD subjects from 2-8 h after treatment (P < or = 0.05). After 1 mg oral E2, total serum E2 peaked at 65 pg/mL at 4 h in ESRD subjects and at 27 pg/mL in control subjects at 8 h. After 2 mg oral E2 treatment, total serum E2 peaked at 8 h in both ESRD and control subjects, with levels of 99 and 37 pg/mL, respectively. E1 was higher in the subjects with ESRD than in the control subjects at baseline (P < 0.05). After ingestion of 1 mg E2, E1 concentrations were not significantly higher in ESRD than in control subjects, peaking at 180 and 121 pg/mL, respectively (P = 0.3). E1 concentrations were higher in ESRD than in control subjects after the ingestion of 2 mg E2, with peak levels of 376 and 201 pg/mL, respectively (P = 0.03). Total and free E2 levels are higher in patients with ESRD than in control subjects at baseline and after E2 ingestion, indicating that renal failure alters the pharmacokinetics of both endogenous and exogenous E2. Therefore, conventional E2 doses used in individuals with normal renal function may be excessive for patients with ESRD.     

Resistant starch decreases serum total cholesterol and triacylglycerol concentrations in rats

Rats were meal-fed semipurified diets containing a low (0.8 g/MJ) and a high (9.6 g/MJ) amount of resistant starch (RS) or various amounts of RS (0.8 to 9.6 g/MJ) and guar gum (0 to 8.8 g/MJ). In one experiment, rats were fed the low and high RS diets in three dietary regimens (ad libitum consuming, 12 h ad libitum/12 h food deprived, and meal fed). Effects of RS and guar gum on serum postprandial and postabsorptive concentrations of total cholesterol (TC) and triacylglycerol (TAG), growth, hydrogen excretion, tissue weights and contents of small intestine and cecum, and pH of cecal contents were investigated. In addition, effects of RS on food intake, de novo hepatic synthesis of fatty acids and neutral sterols, and on lipoprotein lipase activity and weight of epididymal fat pads were investigated. Compared with feeding the low RS diet, the high RS diet reduced the serum TC and TAG concentrations, with these effects observed after 1 and 2 wk of feeding, respectively. The dietary regimen did not influence the effect of RS on the serum TC and TAG concentrations, but it did affect the serum TAG concentration. Resistant starch had no effect on the hepatic synthesis of fatty acids and neutral sterols or on the lipoprotein lipase activity in epididymal fat pads. Guar gum also reduced the serum TC concentration, but it had no effect on serum TAG concentration. The tissue weights and contents of small intestine and cecum as well as hydrogen excretion increased with increasing amounts of dietary RS and guar gum, whereas the pH of cecal contents decreased. No effects of RS on food intake and total body weight gain were found, whereas guar gum decreased weight gain. Feeding the high RS diet also led to a lower weight of the epididymal fat pads. We conclude that dietary RS can reduce serum TC and TAG concentrations and fat accretion.     

The activity of thymidine phosphorylase in the uterine myomas and the myometrium in perimenopausal women

The activity of thymidine phosphorylase (dThdPase) in the myometrium and uterine myomas has been investigated in perimenopausal women. Differences in the activity of dThdPase have been found depending on the myoma type, menopause stage and the phase of the menstrual cycle in which the surgery was performed. The enzyme in the cytoplasmatic soluble fraction obtained at 50,000 x g was the most active in cellular leiomyomas of the follicular phase, the least in adenomyomas of the luteal phase of the menstrual cycle, whereas its activity in myometrium was always unchanged. Greater differences can be observed in the activity of dThdPase after a partial purification of the enzyme from myomas. It seems that the increase in dThdPase activity may point to its correlation with transient, premalignant tumor which may later transform into malignant forms.     

Blood pressure and plasma norepinephrine responses to dexfenfluramine in obese postmenopausal women

The study of social and emotional development is recognized for its complexity. To better understand developmental norms, and deviations thereof, researchers typically focus on individual (e.g., temperament), interactional (e.g., parenting behaviors), and relational (e.g., attachment, friendship) levels of analysis. Often forgotten, however, is the extent to which cultural beliefs and norms play a role in the interpretation of the acceptability of individual characteristics and the types and the ranges of interactions and relationships that are likely or permissible. This special issue comprises four sections in which culture is examined insofar as it relates to the aforementioned levels of social analysis: "Emotional Development," "Parenting and Parent-Child Relationships," "Social Cognition and Social Relationships," and "Social and Emotional Adjustment and Maladjustment." Each section is followed by a commentary.     

Soy isoflavones improve systemic arterial compliance but not plasma lipids in menopausal and perimenopausal women

The possibility that the heightened cardiovascular risk associated with the menopause, which is said to be ameliorated by soybeans, can be reduced with soy isoflavones was tested in 21 women. Although several were perimenopausal, all have been included. A placebo-controlled crossover trial tested the effects of 80-mg daily isoflavones (45 mg genistein) over 5- to 10-week periods. Systemic arterial compliance (arterial elasticity), which declined with age in this group, improved 26% (P < .001) compared with placebo. Arterial pressure and plasma lipids were unaffected. The vasodilatory capacity of the microcirculation was measured in nine women; high acetylcholine-mediated dilation in the forearm vasculature was similar with active and placebo treatments. LDL oxidizability measured in vitro was unchanged. Thus, one important measure of arterial health, systemic arterial compliance, was significantly improved in perimenopausal and menopausal women taking soy isoflavones to about the same extent as is achieved with conventional hormone replacement therapy.