Biologic variation of common hematologic laboratory quantities in the elderly

Analytic, within-subject, and between-subject biologic variations were estimated for leukocytes, erythrocytes, hemoglobin, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin content (MCHC), platelets, and a three-component differential count (lymphocytes, monocytes, and granulocytes in terms of both concentration and percentage of leukocytes) in cohorts of 12 male and 12 female healthy elderly subjects. The assays were performed with an Ortho ELT-800 automated analyzer. The estimates of within-subject biologic variation were similar to published data on young subjects, indicating that this aspect of homeostasis is not compromised in the elderly. The data were used to derive objective analytic goals; goals were surpassed except for assays of erythrocytes, hematocrit, and the derived MCV, MCH, and MCHC. The changes required for serial results to be significantly different were determined and found to be generally valid because most quantities have no heterogeneity of within-subject variation. All quantities had significant individuality; in consequence, conventional population-based reference values are of limited utility, and screening using reference limits will not detect latent or early disease in many subjects.     

The dental caries status and dental treatment patterns of 12-year-old children in Hong Kong

A randomly selected sample of 662 12-year-old Hong Kong children, 529 of whom were Southern Chinese and 133 non-Chinese, was clinically examined for dental caries. The DMFT values were 2.76 and 1.66 for the Chinese and non-Chinese children, respectively. The D component for the Chinese children was 2.12, while for the non-Chinese children it was only 0.45. Approximately 24.0% of the Chinese children had attended the dentist because they were in pain. Only 3.8% of the Chinese children had sought orthodontic or preventive treatment, compared with 24.0% of the non-Chinese children. Although these findings indicate the caries experience to be well below the FDI/WHO global goal for the year 2000, there is a great need to increase the level of dental awareness among Chinese children.     

Inadequate dietary magnesium intake increases atherosclerotic plaque development in rabbits

Epidemiological studies have shown dietary magnesium (Mg) intake and serum Mg levels to be inversely correlated with the development of atherosclerosis. We hypothesized that low levels of Mg would promote atherosclerotic plaque development in rabbits. New Zealand white rabbits (4 months old, n = 22) were fed an atherogenic diet containing 0.12% (−Mg), 0.27% (control), or 0.43% (+Mg) Mg for 8 weeks. Blood samples were obtained at baseline, 2, 4, 6, and 8 weeks and were assayed for total cholesterol, high-density lipoprotein (HDL), non-HDL, triglycerides (TG), C-reactive protein, serum Mg, and erythrocyte Mg. Aortas from −Mg had significantly more plaque, with an intima thickness 42% greater than control and 36% greater than +Mg. Serum cholesterol levels rose over time, and at 8 weeks, −Mg had the highest and +Mg the lowest total and non-HDL cholesterol and TG levels, although these results did not reach significance. Over time, serum Mg levels increased, and erythrocyte Mg levels decreased. C-reactive protein significantly increased in all groups at 4 and 6 weeks but returned to baseline levels by 8 weeks. This study supports the hypothesis that inadequate intake of Mg results in an increase in atherosclerotic plaque development in rabbits.     

Newly developed hybrid suture without lubricant: noninvasive in vivo assessment of biocompatibility with multiparametric MR imaging.

Magnetic resonance imaging (MRI) and magnetic resonance (MR) relaxometry were used to assess noninvasively the tissue response of a new uncoated hybrid braided suture made from a combination of ultra-high-molecular-weight polyethylene (UHMWPE) and polyester (polyethylene terephthalate) (PET) yarns in comparison to a silicone impregnated braided 100% polyester (PET) control suture (Ticron). Both biomaterials were monitored for a period of 30 days following implantation in both incised and nonincised paravertebral rabbit muscles. In all cases, MR images and relaxometry demonstrated that the hybrid suture elicited either a milder or a similar tissue and cellular response compared to the control suture. These findings were confirmed by conventional histological analysis of the surrounding tissues. They also demonstrated that the hybrid suture promoted faster healing in terms of collagen infiltration between the yarns and individual filaments. This milder inflammatory reaction and improved biocompatibility represent a real advantage in the healing performance of sutures for cardiac and vascular surgery, and support the need for continued research and development of hybrid structures. This study also demonstrated the ability of MRI techniques to noninvasively evaluate the biocompatibility of biomaterials. By extending the capacity of MR diagnostic tools from patients to experimental animals, it is now possible to validate the healing performance of foreign materials with statistical reliability and fewer animals.     

Transmission of STIs/HIV at the partnership level: Beyond individual-level analyses

Mathematical modeling of transmission dynamics of sexually transmitted infections (STIs) and HIV has considerably advanced HIV research by highlighting the importance of certain types of partnerships in epidemic spread. Notably, concurrent partnerships, defined as a sexual partnership in which one or more of the partnership members have other sexual partners while continuing sexual activity with the original partner, have been shown to play a fundamental role in potentiating the spread of STIs and HIV. Risk behaviors such as concurrency and sex without condoms as well as STI/HIV prevalence vary with physical, social, and emotional factors within partnerships. The efficiency of STI/HIV transmission appears to vary across types of concurrent partnerships according to the differing dynamics within them. Previous research on partnership dynamics has improved our understanding of the multidimensional aspects of sexual partnering, but little is understood of how these aspects of sexual partnering interact and increase risks for HIV, nor how types of partnerships, partnership dynamics, and concurrency work together to affect both the behavior of condom use and the biological transmission of disease. In this article, we discuss the need to extend our understanding of concurrency to include partnerships among men who have sex with men (MSM) and to differentiate between types of partnerships and to develop interventions to modify risk within partnerships. We also introduce a conceptual framework that reflects how individual and partner characteristics influence partnership dynamics that in turn influence risk behaviors, such as concurrency and not using condoms, and associated risks for STIs and HIV.     

Comparison of fetal cerebellar measurements by two different techniques.

We examined 53 fetuses between 15 and 40 weeks of gestation with transverse and coronal sections of the head in order to evaluate the accuracy and reproducibility of the coronal cerebellar diameter. Intraobserver coefficient of variation was less than or equal to 2.2% and the mean interobserver difference was 2.2% (range, 0 to 6%). A positive linear correlation exists between transverse and coronal measurements (coronal diameter = 1.02 x transverse diameter - 0.48; R2 = 0.99; P less than 0.0001). We conclude that the coronal cerebellar diameter is reproducible and accurate and when indicated clinically can be used instead of the transverse cerebellar diameter when the latter is not obtainable because of fetal position.     

Influence of complement on sperm motility

Isolated sperm from normo-, oligo- and astheno-spermic men were incubated for 20 h in medium supplemented with 8% heat-inactivated or untreated human serum, and in medium with heated or untreated serum deficient in complement factor C3. Before and after incubation, sperm motility was assessed by means of a computer-assisted semen analyser. The results did not show significant differences between the motility of sperm incubated in heated or untreated serum. It is concluded that heating of homologous serum is not necessary for preserving sperm motility and in some cases may even be disadvantageous.