The effect of snacking and eating frequency on dietary quality in British adolescents.

PURPOSE: To describe the effects of number of eating occasions and snacks on dietary quality (DQ), defined as adherence to dietary recommendations. METHODS: A sample of 884 adolescents (11-18 years) in the UK National Diet and Nutrition Survey (NDNS) were included. The Diet Quality Index for Adolescents (DQI-A) was implemented. The total number of eating occasions and snacks was frequency of food or beverages consumed over 24 h and frequency of foods or beverages consumed outside of the three mealtimes, respectively. Results were generated with and without low-energy food under 210 kJ (50 kcal). Regression models were generated with DQ score as the outcome variable and number of eating occasions and snacks as predictors. RESULTS: The mean (95 % CI) DQ score was 31.1 % (30.2, 32.0). The mean number of eating occasions and snacks was 7.5 (7.3, 7.7) and 2.6 (2.6, 2.7) times/day, respectively. When low-energy events were excluded, the mean number of eating occasions and snacks reduced to 6.2 (6.1, 6.4) and 2.0 (2.0, 2.1) times/day, respectively. DQ score increased by 0.74 points (0.42, 1.05; p < 0.01) and 0.55 points (-0.08, 0.69; p = 0.17) for total eating occasions and snacks, respectively. When low-energy events were excluded, DQ score increased by 0.30 points (-0.84, 0.69; p = 0.13) for each eating occasion and decreased by 1.20 points (-2.1, -0.3; p < 0.01) for each snack. CONCLUSION: Eating more frequently improves dietary quality especially if some eating occasions are low in energy. A focus on replacing high-energy snacks with low-energy alternatives rather than reducing the number of eating occasions may result in improved dietary quality in adolescents.

Association between sugar-sweetened and artificially sweetened soft drinks and type 2 diabetes: systematic review and dose-response meta-analysis of prospective studies.

The intake of sugar-sweetened soft drinks has been reported to be associated with an increased risk of type 2 diabetes, but it is unclear whether this is because of the sugar content or related lifestyle factors, whether similar associations hold for artificially sweetened soft drinks, and how these associations are related to BMI. We aimed to conduct a systematic literature review and dose-response meta-analysis of evidence from prospective cohorts to explore these issues. We searched multiple sources for prospective studies on sugar-sweetened and artificially sweetened soft drinks in relation to the risk of type 2 diabetes. Data were extracted from eleven publications on nine cohorts. Consumption values were converted to ml/d, permitting the exploration of linear and non-linear dose-response trends. Summary relative risks (RR) were estimated using a random-effects meta-analysis. The summary RR for sugar-sweetened and artificially sweetened soft drinks were 1·20/330 ml per d (95 % CI 1·12, 1·29, P< 0·001) and 1·13/330 ml per d (95 % CI 1·02, 1·25, P= 0·02), respectively. The association with sugar-sweetened soft drinks was slightly lower in studies adjusting for BMI, consistent with BMI being involved in the causal pathway. There was no evidence of effect modification, though both these comparisons lacked power. Overall between-study heterogeneity was high. The included studies were observational, so their results should be interpreted cautiously, but findings indicate a positive association between sugar-sweetened soft drink intake and type 2 diabetes risk, attenuated by adjustment for BMI. The trend was less consistent for artificially sweetened soft drinks. This may indicate an alternative explanation, such as lifestyle factors or reverse causality. Future research should focus on the temporal nature of the association and whether BMI modifies or mediates the association.

Techniques of assessing hypoxia at the bench and bedside.

Tissues require an adequate supply of oxygen in order to maintain normal cell function. Low oxygen tension (hypoxia) is characteristic of a number of conditions, including cancer, atherosclerosis, rheumatoid arthritis, critical limb ischaemia, peripheral vascular disease, and ischaemic heart disease. Tissue hypoxia is found in tumours, atherosclerotic plaque, and ischaemic myocardium. There is a growing interest in methods to detect and assess hypoxia, given that hypoxia is important in the progression of these diseases. Hypoxia can be assessed at the level of the whole organ, tissue, or cell, using both invasive and non-invasive methods, and by a range of immunohistochemical, biochemical, or imaging techniques. This review describes and critiques current methods of assessing hypoxia that are used at the bench and in clinical practice.

The effect of feed processing of novel unheated, low trypsin inhibitor soybeans on the performance of young female turkeys reared from hatch to 21 days of age.

The objective of this study was to evaluate the effects of dietary inclusion of a novel low trypsin inhibitor soybean (LTI) fed as mash or crumbled pellet form on the productive performance and digestibility in turkey poults from hatch to 21 d. A total of 336 Hybrid Converter turkey poults were allocated in groups of 7 to 6 treatments, each with 8 replicate cages. Treatments were arranged as a 3 × 2 factorial with inclusion level of the low trypsin-inhibitor soybean (0, 20, and 40% LTI) and feed form (mash and crumbled pellet). A single batch of feed was mixed for each inclusion level and divided into 2 aliquots: one remaining as mash and the other conditioned at 82°C for approximately 30 s, pelleted and then crumbled. On d 7, 14, and 21 posthatching, BW, and feed intake (FI) were recorded and BW gain (BWG) and feed conversion ratio (FCR) calculated. Excreta samples were collected from d 19 to 21 and pooled by cage. At d 21, intestines were excised, pancreas weights recorded (PRW), and ileal contents collected. There were no interactions (linear, P > 0.05) between LTI inclusion and feed form on BW, BWG, FI, or FCR at d 7 or 21. Increasing LTI resulted in a linear reduction in BW at 7, 14, and 21 d (P < 0.006). Poults fed crumbles were significantly heavier at d 21 than those fed mash feed (P < 0.027) with no interaction of LTI level with feed form. FCR was not significantly greater with increasing LTI. However, poults fed crumbles had a better, lower FCR that those fed mash feed from d 0 to 21 (P < 0.018). There was a significant interaction between feed form and LTI level at 14 d (P < 0.031), but not 7 or 21 d. Pancreatic hypertrophy (PRW) increased linearly with increasing LTI (P < 0.001) with a significant linear interaction with feed form (P < 0.001). Poults fed crumbles had less pancreatic hypertrophy. At 21 d of age, dietary fat digestibility (ALD, %) was linearly reduced with increasing LTI (P < 0.001). However, poults fed crumbles had significantly better fat absorption than poults fed mash (91.2 vs. 85.8%) (P < 0.001), and there was a significant linear interaction between feed form and LTI level (P < 0.001). AMEn was significantly better for the poults fed crumbles compared to mash (3228 vs. 3132 kcal/kg) (P < 0.001), and there was a significant linear interaction between feed form and LTI level (P < 0.001). Based on the results this trial, it is possible to include up to 20% unheated full fat LTI soybeans into poult starter diets after pelleting. Pelleting improves nutrient utilization, allowing for greater incorporation of the LTI soybean in the crumbled diet compared to the mash diet.

Alterations in corticostriatal synaptic plasticity in mice overexpressing human alpha-synuclein.

Most forms of Parkinson's disease (PD) are sporadic in nature, but some have genetic causes as first described for the alpha-synuclein gene. The alpha-synuclein protein also accumulates as insoluble aggregates in Lewy bodies in sporadic PD as well as in most inherited forms of PD. The focus of the present study is the modulation of synaptic plasticity in the corticostriatal pathway of transgenic (Tg) mice that overexpress the human alpha-synuclein protein throughout the brain (ASOTg). Paired-pulse facilitation was detected in vitro by activation of corticostriatal afferents in ASOTg mice, consistent with a presynaptic effect of elevated human alpha-synuclein. However basal synaptic transmission was unchanged in ASOTg, suggesting that human alpha-synuclein could impact paired-pulse facilitation via a presynaptic mechanism not directly related to the probability of neurotransmitter release. Mice lacking alpha-synuclein or those expressing normal and A53T human alpha-synuclein in tyrosine hydroxylase-containing neurons showed, instead, paired-pulse depression. High-frequency stimulation induced a presynaptic form of long-term depression solely in ASOTg striatum. A presynaptic, N-methyl-d-aspartate receptor-independent form of chemical long-term potentiation induced by forskolin (FSK) was enhanced in ASOTg striatum, while FSK-induced cAMP levels were reduced in ASOTg synaptoneurosome fractions. Overall the results suggest that elevated human alpha-synuclein alters presynaptic plasticity in the corticostriatal pathway, possibly reflecting a reduction in glutamate at corticostriatal synapses by modulation of adenylyl cyclase signaling pathways. ASOTg mice may recapitulate an early stage in PD during which overexpressed alpha-synuclein dampens corticostriatal synaptic transmission and reduces movement.

A history and review of school meal standards in the UK.

This review details the history of school meals in the UK, from their origin in the mid-19th Century, to the present day, and provides a summary of how each country has independently developed its own food and or nutrient-based standards for school meals. The standards in place in the UK are amongst some of the most detailed and comprehensive in the world. Regular monitoring to ensure that these standards are being met and that schools are improving healthy eating is essential to their success. Of no lesser importance are assessments to determine whether changes to school meals are having an impact on the diets of school children. It is early days in terms of evaluation because food-based standards have only recently been introduced and nutrient-based standards are in the process of being developed and implemented. Studies in England provide some evidence that the re-introduction of standards for school food is having a positive impact on both pupil's food choices and the nutritional profile of school lunches. At present, there does not appear to be a pattern between current obesity levels and the types of school meals provided, although it is anticipated that, in the long term, these comprehensive standards may contribute to a less obesogenic environment.

Interventions to reduce consumption of sugar-sweetened beverages or increase water intake: evidence from a systematic review and meta-analysis.

A systematic review and meta-analyses were conducted to evaluate the effects of interventions to reduce sugar-sweetened beverages (SSB) or increase water intakes and to examine the impact of behaviour change techniques (BCTs) in consumption patterns. Randomized and nonrandomized controlled trials published after January 1990 and until December 2016 reporting daily changes in intakes of SSB or water in volumetric measurements (mL d-1 ) were included. References were retrieved through searches of electronic databases and quality appraisal followed Cochrane principles. We calculated mean differences (MD) and synthesized data with random-effects models. Forty studies with 16 505 participants were meta-analysed. Interventions significantly decreased consumption of SSB in children by 76 mL d-1 (95% confidence interval [CI] -105 to -46; 23 studies, P < 0.01), and in adolescents (-66 mL d-1 , 95% CI -130 to -2; 5 studies, P = 0.04) but not in adults (-13 mL d-1 , 95% CI -44 to 18; 12 studies, P = 0.16). Pooled estimates of water intakes were only possible for interventions in children, and results were indicative of increases in water intake (MD +67 mL d-1 , 95% CI 6 to 128; 7 studies, P = 0.04). For children, there was evidence to suggest that modelling/demonstrating the behaviour helped to reduce SSB intake and that interventions within the home environment had greater effects than school-based interventions. In conclusion, public health interventions - mainly via nutritional education/counselling - are moderately successful at reducing intakes of SSB and increasing water intakes in children. However, on average, only small reductions in SSBs have been achieved by interventions targeting adolescents and adults. Complementary measures may be needed to achieve greater improvements in both dietary behaviours across all age groups.

Cyclic hydrostatic pressure and particles increase synthesis of 1,25-dihydroxyvitamin D3 by human macrophages in vitro.

1,25-Dihydroxyvitamin D(3) has a pivotal role in bone resorption and osteoclast activity. As activated macrophages are known to synthesise 1,25-dihydroxyvitamin D(3), this study examined whether pressure modulated its synthesis. Pressure and particles have been shown to increase synthesis of pro-resorptive cytokines and other factors by cultured macrophages. Human peripheral blood macrophages were isolated, cultured and exposed to pressure (similar to that found in the human joint) and/or particles. Synthesis of 1,25-dihydroxyvitamin D(3) by macrophages was assayed using high pressure liquid chromatography and in situ hybridization. Synthesis of 1,25-dihydroxyvitamin D(3) but not 24,25-dihydroxyvitamin D(3) was increased in macrophages under pressure. In situ hybridization demonstrated an increase in 1alpha-hydroxylase expression in response to pressure or particles and simultaneous exposure to both stimuli generated higher expression of 1alpha-hydroxylase. In conclusion, this is the first study to demonstrate that mechanical loading, in the form of pressure, stimulates 1,25-dihydroxyvitamin D(3) synthesis in human macrophages. These findings have implications for the in vivo situation, as they suggest that 1,25-dihydroxyvitamin D(3) could be one factor stimulating osteoclastic bone resorption in pathologies, such as arthritis or implant loosening, where intra-articular or intra-osseous pressure is raised or where wear particles interact with macrophages.

Age of donor alters the effect of cyclic hydrostatic pressure on production by human macrophages and osteoblasts of sRANKL, OPG and RANK.

BACKGROUND: Cyclic hydrostatic pressure within bone has been proposed both as a stimulus of aseptic implant loosening and associated bone resorption and of bone formation. We showed previously that cyclical hydrostatic pressure influenced macrophage synthesis of several factors linked to osteoclastogenesis. The osteoprotegerin/soluble receptor activator of NF-kappa beta ligand /receptor activator of NF-kappa beta (OPG/ RANKL/ RANK) triumvirate has been implicated in control of bone resorption under various circumstances. We studied whether cyclical pressure might affect bone turnover via effects on OPG/ sRANKL/ RANK. METHODS: In this study, cultures of human osteoblasts or macrophages (supplemented with osteoclastogenic factors) or co-cultures of macrophages and osteoblasts (from the same donor), were subjected to cyclic hydrostatic pressure. Secretion of OPG and sRANKL was assayed in the culture media and the cells were stained for RANK and osteoclast markers. Data were analysed by nonparametric statistics. RESULTS: In co-cultures of macrophages and osteoblasts, pressure modulated secretion of sRANKL or OPG in a variable manner. Examination of the OPG:sRANKL ratio in co cultures without pressurisation showed that the ratio was greater in donors <70 years at the time of operation (p < 0.05 Mann Whitney U) than it was in patients >70 years. However, with pressure the difference in the OPG:sRANKL ratios between young and old donors was not significant. It was striking that in some patients the OPG:sRANKL ratio increased with pressure whereas in some it decreased. The tendency was for the ratio to decrease with pressure in patients younger than 70 years, and increase in patients > or = 70 years (Fishers exact p < 0.01). Cultures of osteoblasts alone showed a significant increase in both sRANKL and OPG with pressure, and again there was a decrease in the ratio of OPG:RANKL. Secretion of sRANKL by cultures of macrophages alone was not modulated by pressure. Only sRANKL was assayed in this study, but transmembrane RANKL may also be important in this system. Macrophages subjected to pressure (both alone and in co-culture) stained more strongly for RANK on immunohistochemstry than non-pressurized controls and 1,25-dihydroxyvitamin D3 (1,25 D3) further increased this. Immunocytochemical staining also demonstrated that more cells in pressurized co-cultures exhibited osteoclast markers (tartrate-resistant acid phosphatase, vitronectin receptor and multinuclearity) than did unpressurized controls. CONCLUSION: These data show that in co-cultures of osteoblasts and macrophages the ratio of OPG : sRANKL was decreased by pressure in younger patients but increased in older patients. As falls in this ratio promote bone resorption, this finding may be important in explaining the relatively high incidence of osteolysis around orthopaedic implants in young patients. The finding that secretion of OPG and sRANKL by osteoblasts in monoculture was sensitive to hydrostatic pressure, and that hydrostatic pressure stimulated the differentiation of macrophages into cells exhibiting osteoclast markers indicates that both osteoblasts and preosteoclasts are sensitive to cyclic pressure. However, the effects of pressure on cocultures were not simply additive and coculture appears useful to examine the interaction of these cell types. These findings have implications for future therapies for aseptic loosening and for the development of tests to predict the development of this condition.

Measuring diet in primary school children aged 8-11 years: validation of the Child and Diet Evaluation Tool (CADET) with an emphasis on fruit and vegetable intake.

BACKGROUND/OBJECTIVES: The Child And Diet Evaluation Tool (CADET) is a 24-h food diary that measures the nutrition intake of children aged 3-7 years, with a focus on fruit and vegetable consumption. Until now CADET has not been used to measure nutrient intake of children aged 8-11 years. To ensure that newly assigned portion sizes for this older age group were valid, participants were asked to complete the CADET diary (the school and home food diary) concurrently with a 1-day weighed record. SUBJECTS/METHODS: A total of 67 children with a mean age of 9.3 years (s.d.: ± 1.4, 51% girls) participated in the study. Total fruit and vegetable intake in grams and other nutrients were extracted to compare the mean intakes from the CADET diary and Weighed record using t-tests and Pearson's r correlations. Bland-Altman analysis was also conducted to assess the agreement between the two methods. RESULTS: Correlations comparing the CADET diary to the weighed record were high for fruit, vegetables and combined fruit and vegetables (r=0.7). The results from the Bland-Altman plots revealed a mean difference of 54 g (95% confidence interval: -88, 152) for combined fruit and vegetables intake. CADET is the only tool recommended by the National Obesity Observatory that has been validated in a U.K. population and provides nutrient level data on children's diets. CONCLUSIONS: The results from this study conclude that CADET can provide high-quality nutrient data suitable for evaluating intervention studies now for children aged 3-11 years with a focus on fruit and vegetable intake.

Bisphosphonates modulate the effect of macrophage-like cells on osteoblast.

Macrophages (MPs) are present in many tissues and have been implicated in the excessive bone resorption seen in patients with skeletal disorders. Our previous studies showed that macrophage-like cells influenced osteoblasts (OB) in co-culture, as number and activity of osteoblasts were decreased in co-cultures compared with controls. Macrophages are probable precursors of osteoblasts which have been shown to be inhibited by bisphosphonates (BPs). Bisphosphonates also modulate macrophage and osteoblasts activity. This study investigated whether addition of bisphosphonates to co-cultures of osteoblast and macrophages could reduce or block the adverse effects of macrophages on osteoblasts. The results showed that, compared to controls, fewer osteoblasts were present over time in macrophage/osteoblast co-cultures (at day 12, 15.5 x 10(4) and 8.8 x 10(4); P<0.0001) and that addition of bisphosphonates (10(-9)-10(-5)M) to the co-cultures prevented this reduction (P<0.001). Bisphosphonates also elicited an increase in numbers of osteoblast (82%) and restored alkaline phosphatase (ALP) activity, which was reduced by 15% (P approximately equal to 0.05) compared to control levels. The number of macrophages in co-cultures was reduced when bisphosphonates were added (P<0.001) and release of lactate dehydrogenase (LDH) was seen, which was not detectable in control cultures. It therefore, appears that bisphosphonates initiated macrophage death. These results demonstrated that the inhibitory effect of macrophages on osteoblasts in vitro could be overcome by the action of bisphosphonates. These findings have implications for the treatment of skeletal conditions where macrophage-derived cytokines are important, such as arthritis and implant loosening, although it is clearly important to distinguish between those bisphosphonates which enhance synthesis of pro-inflammatory cytokines and those which inhibit such synthesis.

Myeloma affects both the growth and function of human osteoblast-like cells.

Myeloma behaves differently to other osteolytic tumours which metastasize to bone, in that the latter usually provoke reactive bone formation in the host bone. A previous study showed that a myeloma cell line (GM1500) secreted an osteoblast-inhibiting factor(s). The present study was undertaken to determine whether other myeloma cells also secreted a factor(s) which inhibited both cell proliferation and DNA synthesis of osteoblast-like cells and whether the myeloma also affected the function of osteoblasts. The results showed that a second cell line (Karpas 707) as well as myeloma tissue taken from two patients had a similar effect. The myeloma cells did not affect total collagen or protein synthesis, and did not affect the overall degree of mineralization. A biphasic effect was seen on alkaline phosphatase activity. Thus, although the proliferation of the pre-osteoblast was affected, the synthetic functions of the osteoblasts were not.

Synergistic effect of particles and cyclic pressure on cytokine production in human monocyte/macrophages: proposed role in periprosthetic osteolysis.

Macrophages, activated by particulate wear debris, are important in the process of osteolysis, which occurs during joint implant loosening. We previously found increased levels of interleukin-1beta (IL-1beta), IL-6, and tumor necrosis factor-alpha in cultured macrophages subjected to cyclical pressure of 0.138 MPa, suggesting that cyclic pressure may be another relevant cause of macrophage activation. The current study first investigated the effects of a range of cyclic pressures on cultured macrophages, including an investigation of the time course of cytokine expression. At 0.138 MPa, supernatant levels of TNF-alpha were maximal at 12 h, whereas IL-6 and IL-1beta were maximal at 24 h. All four cyclic pressure levels tested (without particles) resulted in increased production of all three cytokines relative to control. These increases were most marked at 0.069 and 0.035 MPa, and the increase in cytokine production at 0.017 MPa was not statistically significant. Further studies demonstrated that conditioned media from cyclically pressurized macrophages stimulated bone resorption in a neonatal mouse calvarial assay system. There were increased levels of calcium released from calvaria cultured in conditioned media from pressurised monocytes, and an increase in tartate-resistant acid phosphatase-positive osteoclasts was observed microscopically. As particulate wear debris is important in implant loosening, ultra high molecular weight polyethylene particles were also added to the pressurized cell cultures. The experiments compared the effect of atmospheric pressure, cyclic pressure alone, particles alone, and particles and cyclic pressure combined. A combination of ultra high molecular weight polyethylene particles and cyclic pressure at 0.017 MPa resulted in a dramatic synergistic elevation of levels of all three cytokines compared with the levels found with either pressure or particles alone. We propose that monocyte/macrophage activation by cyclic pressure plays a major role in the osteolysis seen in aseptic loosening of implants. The synergistic effect observed between particles and pressure could accelerate implant loosening, and implies that reduction in either cyclic pressure (by improving implant fixation) or wear debris load would reduce osteolysis.

Home blood pressure-measuring devices: a comparative study of accuracy.

Self monitoring of blood pressure by hypertensive patients has been shown to be of value and is increasingly popular. However, the accuracy and ease of use of at least some of the equipment for home use is questionable. We tested 23 pairs of home blood pressure devices, using static methods, trained observers with volunteer subjects and hypertensive patients. Eleven (48%) of the 23 pairs of devices tested were found inconsistent with their duplicate and failed the standards for automated devices of the Association for the Advancement of Medical Instrumentation. Several of the devices, all sold for home use by lay people, contained no instructions whatsoever and even patients using those machines with instructions required further training in blood pressure measurement. While home blood pressure monitoring is useful in certain circumstances, care must be taken in the choice of device, and training is required for all devices.

Hypertension control in two Canadian communities: evidence for better treatment and overlabelling.

We evaluated the prevalence and control of hypertension in two Canadian cities without university medical centre facilities. A stratified multistage probability sample was selected, and we interviewed 6258 adults between the ages of 30 and 69 inclusive. Blood pressure measurements were obtained during home interviews. Up to two further visits were made to people with untreated blood pressure elevation. By a diagnostic criterion of 90 mmHg, the hypertension prevalence was 114/1000. Six per cent of the hypertensives were undetected, 6% detected but untreated, 17% treated but uncontrolled and 70% were being treated and controlled. Control was better in females and older subjects. These findings show no disadvantages to hypertensives living away from university medical centres. We found a hypertension prevalence of 143/1000 among people who reported being diagnosed as hypertensive but who had normal blood pressure while not on medication. These results suggest a problem with over-labelling of hypertensives.

Breast carcinomas synthesize factors which influence osteoblast-like cells independently of osteoclasts in vitro.

Bone metastases in breast cancer may be osteolytic, osteosclerotic, or a mixture of the two. Although stimulation of bone resorption by breast cancer cells has attracted some interest, the formation of osteosclerotic secondary tumours and the influence of human mammary carcinoma cells on osteoblasts (bone forming cells), both important in understanding breast cancer--bone interactions, have been largely neglected. We therefore examined the effects of conditioned medium (CM) from two cultured human breast cancer cell lines (MCF7 and ZR-75) and from primary cultures of breast carcinomas from two patients, on osteoblasts and recruitment of bone-resorbing cells (osteoclasts) in vitro. Osteoblast-like cells (BDC) were cultured from human trabecular bone explants. Osteoclast maturation was studied in fetal rat calvaria cultured on collagen gels. CM from the MCF-7 line and cells derived from one patient each inhibited BDC DNA synthesis, but stimulated osteoclast recruitment. In contrast, CM from the second patient's cells or ZR-75 enhanced DNA synthesis in BDC, but blocked osteoclast maturation. This suggests that human breast carcinomas secrete soluble factors which influence both osteoclasts and osteoblasts. A further unexpected implication is that mammary carcinoma cells may cause local osteosclerosis by directly stimulating osteoblasts, rather than through raised bone turnover in metastases.

Interaction of amosite and surface-modified amosite with a V79-4 (Chinese hamster lung) cell line.

We have been examining a number of chemically modified mineral fibers, derived from amosite asbestos, by in vitro methods to clarify the role of the fiber surface in determining biological activity. The various fibers have identical size distributions but differ in their affinities for components of the cell membrane. They were treated with boiling toluene or chemically modified by treatment with alkyldimethylchlorosilanes (R = C8, C18) that react with free-surface hydroxyl groups to form the corresponding siloxanes. Fibers in MEM supplemented with 15% fetal calf serum were added to a suspension of V79-4 cells labeled with tritiated thymidine and the mixture was incubated. Aliquots of this mixture were spun down on a density gradient to determine the degree of cell-fiber interaction. At 37 degrees C native amosite (UICC standard) stuck to cells within 15 min of incubation, and the amount of sticking was maximum within 70 min. Decreasing the temperature decreased the amount of sticking, and at 20 degrees C no sticking was observable. The chemically modified amosite and the amosite treated with boiling toluene did not stick to the cells even after 70 min. Soaking the toluene-treated amosite with aqueous solutions at room temperature for 48 hr produced a material that had the same sticking properties as the original untreated fiber. These results indicate that the silanol content, and possibly the degree of hydration of the fiber surface, is important for a fiber to stick to a cell surface.

Selective opportunistic screening for hypercholesterolemia in primary care practice.

OBJECTIVES: To assess the performance of selective opportunistic screening in a primary care group practice. DESIGN: Cross-sectional survey of coronary heart disease risk factors and retrospective chart audit of cholesterol testing. SETTING: Capitation-funded primary care group practice in Ontario, Canada. SUBJECTS: 7785 enrolled patients between the ages of 20 and 69 years. INTERVENTION: Protocol-based selective opportunistic screening program for hypercholesterolemia of 45 months duration. MAIN OUTCOME MEASURES: Targeting (proportion of screening tests that were appropriate), coverage (proportion of those meeting screening criteria who had a screening test performed), over-screening (proportion of those not meeting screening criteria who had a screening test performed), and screening ratio (likelihood that a screening test was performed on an individual who met screening criteria rather than one who failed to meet screening criteria). RESULTS: 64.7% of patients tested met the practice criteria for screening. 37.7% of patients who met the practice screening criteria were tested and 24.9% of those not meeting practice screening criteria had a cholesterol test performed. The screening ratio was 1.52. CONCLUSION: Our findings bring into question the effectiveness of opportunistic approaches to preventive care.

Internal carotid artery aneurysm: a singular anomaly.

A 9-year-old Indian boy was found to have an aneurysm of the left internal carotid artery. The vessel was heavily atherosclerosed, and the distal segment of the artery was tortuous and dilated. Serum lipid estimations showed the presence of type IIB hyperlipoproteinemia, with evidence of the disease in the patient's identical twin sibling and 37-year-old father. There was also a marginal increase in serum triglycerides in a 4-year-old younger brother. The patient's 29-year-old mother was unaffected. The patient had suffered hemolytic disease as a newborn, which resulted in kernicterus and subsequent mental retardation. This incident is considered to have been the result of a proven glucose-6-phosphate dehydrogenase deficiency. The aneurysm was resected and arterial continuity was ensured by using an end-to-end anastomosis. Post-operative blood flow studies showed normal flow patterns in the reconstituted artery. Postoperatively, the patient's mental performance increased dramatically; it is hypothesized that such progress is the consequence of an improvement in the blood supply to the limbic system, following the operative procedure.

Effect of donor age on the growth in vitro of cells obtained from human trabecular bone.

The proliferation of human bone-derived cells (BDCs) was assessed in vitro, using [3H]thymidine incorporation and cell counting in a haemacytometer. The cells were cultured from human trabecular bone from 87 patients aged 2-88 years. The in vitro growth of these cells was unaffected by the chronological age of the donor. However, the cell number at confluence was shown to decrease with increasing donor age, this trend being most marked after 60 years of age. Other assays of the metabolic efficiency of the BDCs, namely, total protein, osteocalcin, and alkaline phosphatase synthesis, did not show any change with increasing donor age. These results suggest that while the ability of individual cells to divide and to perform specific synthetic activities is unimpaired with increasing age, other subtler changes may occur, leading to a decrease in the bone's osteogenic capacity.