How Safe Is Exercise during Pregnancy?

Increasing numbers of women include exercise even during pregnancy as an essential part of their daily routines. Because of the additional physiological demands imposed by pregnancy, health-care practitioners must determine whether or not aerobic exercise is, in fact, healthy for the expectant mother and developing fetus. This article examines whether or not the traditional advice that women receive regarding exercise during pregnancy is supported by the existing scientific literature.     

SERUM ZINC CONCENTRATIONS IN GROWING PREMATURE INFANTS

ABSTRACT. Serial serum zinc concentrations were measured in 31 relatively well, growing premature infants during the first 26 weeks of life. Zinc concentrations declined progressively from 17.9 μmol (1.17 mg/1) at birth (normal adult value) to 8.9 μmol (0.58 mg/1) at 6 weeks of age despite a zinc intake of greater than 13.7 μmol (900 μg)/kg/day after the second week of life. The serum zinc increased after 16 weeks of age to 10.7 μmol/dl (0.7 mg/1). No infant demonstrated clinical signs of zinc deficiency. This data may serve as a reference against which serum zinc concentrations in other premature infants may be compared in order to help define the deficiency state.     

Mapping the receptor-recognition site of human transforming growth factor-α

The receptor-recognition site human transforming growth factor-α (TGFα), a 50-residue tricyclic peptide with three disulfide bonds, was mapped by a set of 46 peptide analogs consisting of linear, monocyclic, bicyclic, and tricyclic structures representing individual and overlapping subdomains of human TGFα. Linear overlapping fragments ranging from 7 to 18 residues and spanning the entire length of TGFα as well as monocyclic analogs with one disulfide linkage were found to be inactive in both receptor-binding and mitogenic assays. Bicyclic analogs with two disulfide linkage and representing either the amino or carboxyl two-thirds of TGFα showed low activity at 0.1–0.9 mm concentrations. Tricyclic analogs containing all three disulfide linkages but lacking either the amino or carboxyl terminal heptapeptide was, respectively, 3% and 0.1 % as active as TGFα. These results show that determinants for the receptor binding cannot be represented by a short continuous fragment or a single subdomain, but are located on a discontinuous surface on a folded structure with disulfide restraints. Furthermore, these results when combined with our previous results which shows that the middle subdomain (second disulfide loop) is not involved in the receptor binding suggest that the receptor-binding residues are constituted of three fragments located at the first and third subdomains as well as the external carboxyl peptide.     

Correlations between human skin bacteria and skin lipids

Correlation matrices were constructed for various human skin variables (propionibacteria, micrococcaceae, sebum excretion rate, percentage of free fatty acids and free fatty acid production rate). Two independent populations were studied (n= 87 and n= 103), and a subpopulation (n= 30) was investigated on three occasions at intervals of 1 month. In this way consistently high correlations could be differentiated from ‘fortuitous’ correlations. Propionibacteria versus micrococcaceae showed the highest correlation coefficient and propionibacteria versus percentage free fatty acids was also highly correlated. A scatter diagram indicated a relationship between the lower threshold of microbial density and sebum excretion rate. An explanation based on relative duct and gland size is presented.     

Plasma Volume Contraction: A Significant Factor in Both Pregnancy-Associated Hypertension (Pre Eclampsia) and Chronic Hypertension in Pregnancy

The role of plasma volume in hypertension in pregnancy (pre-eclampsla)was investigated. Significant volume expansion from non-pregnantlevels (16·5 ± 1·60 ml/cm height) was presentthroughout pregnancy in 189 normal women, reaching 23·1± 1·21 ml/cm at 33–36 weeks amenorrhoea.In another 40 initially normotensive pregnant women who developedhypertension, simllar early volume expansion was followed bysignificant volume contraction in the third trimester, beforeelevation of blood pressure in 29 (20·6 ± 1·26ml/cm), after it in 11(18·6 ± 1·27 ml/cm).Equivalent volume contraction was present in another 44 womenstudied only after hypertension developed in the third tri mester.Oedema had no value as a clinical sign. In another 30 women with chronic hypertension, blood pressurewas inversely related to plasma volume (r = –0·822)and to fetal growth (r = –0·710), which was directlyrelated to plasma volume (r=0·701). Plasma volume depletionplays a significant role in hypertension in pregnancy.     

Flexural Strength and Modulus Properties of Carbamide Peroxide–Treated Bovine Dentin

Background : The effects of carbamide peroxide bleach on tooth structure are uncertain.
Purpose : The purpose of this study was to investigate the effects of direct or indirect carbamide peroxide application on dentin flexural strength and modulus in vitro.
Materials and Methods : Dentin bars were machined from bovine incisors and treated with 10% carbamide peroxide for 6 h/d for 14 days. Four groups were created, with eight bars in each group: group 1–direct bleach application only; group 2–indirect bleach application only; group 3–direct bleach application followed by a 2–week storage in artificial saliva; group 4–direct bleach application followed by a 2-week storage in artificial saliva and daily topical fluoride treatments. The specimens' flexural strength and modulus were tested after 24 hours, and the results were compared with water controls using independent t -tests ( p < .05).
Results : Flexural strength results (in megapascals) for bleached versus control dentin (1 = 205 ± 26 vs 215 ± 14,2 = 257 ± 25 vs 261 ± 14,3 = 180 ± 22 vs 193 ± 36, 4 = 157 ± 18 vs 184 ± 11) were significantly lower in group 4 ( p = .005). Modulus results (in gigapascals) for bleached versus control dentin (1 = 10.7 ± 1.4 vs 12.2 ± 0.6, 2 = 14.2 ± 1.7 vs 14.4 ± 1.6, 3 = 10.0 ± 2.0 vs 10.9 ± 1.3, 4 = 9.0 ± 1.2 vs 11.1 ± 1.0) were significantly lower in groups 1 and 4 ( p = .013 and p = .003, respectively). There were no significant differences in strength and modulus results between the bleached and control dentin in groups 2 and 3. A direct application of carbamide peroxide to bovine dentin significantly decreased some dentin mechanical properties in vitro. An indirect application of carbamide peroxide to dentin did not significantly decrease dentin strength and stiffness.     

The effectiveness of brief alcohol interventions in primary care settings: A systematic review

Issues. Numerous studies have reported that brief interventions delivered in primary care are effective in reducing excessive drinking. However, much of this work has been criticised for being clinically unrepresentative. This review aimed to assess the effectiveness of brief interventions in primary care and determine if outcomes differ between efficacy and effectiveness trials. Approach. A pre‐specified search strategy was used to search all relevant electronic databases up to 2006. We also hand‐searched the reference lists of key articles and reviews. We included randomised controlled trials (RCT) involving patients in primary care who were not seeking alcohol treatment and who received brief intervention. Two authors independently abstracted data and assessed trial quality. Random effects meta‐analyses, subgroup and sensitivity analyses and meta‐regression were conducted. Key Findings. The primary meta‐analysis included 22 RCT and evaluated outcomes in over 5800 patients. At 1 year follow up, patients receiving brief intervention had a significant reduction in alcohol consumption compared with controls [mean difference: ?38 g week^?1, 95%CI (confidence interval): ?54 to ?23], although there was substantial heterogeneity between trials (I² = 57%). Subgroup analysis confirmed the benefit of brief intervention in men but not in women. Extended intervention was associated with a non‐significantly increased reduction in alcohol consumption compared with brief intervention. There was no significant difference in effect sizes for efficacy and effectiveness trials. Conclusions. Brief interventions can reduce alcohol consumption in men, with benefit at a year after intervention, but they are unproven in women for whom there is insufficient research data. Longer counselling has little additional effect over brief intervention. The lack of differences in outcomes between efficacy and effectiveness trials suggests that the current literature is relevant to routine primary care. [Kaner EFS, Dickinson HO, Beyer F, Pienaar E, Schlesinger C, Campbell F, Saunders JB, Burnand B, Heather N. The effectiveness of brief alcohol interventions in primary care settings: A systematic review. Drug Alcohol Rev 2009;28:301–323]