Diet changes due to urbanization in South Africa are linked to microbiome and metabolome signatures of Westernization and colorectal cancer.

Transition from traditional high-fiber to Western diets in urbanizing communities of Sub-Saharan Africa is associated with increased risk of non-communicable diseases (NCD), exemplified by colorectal cancer (CRC) risk. To investigate how urbanization gives rise to microbial patterns that may be amenable by dietary intervention, we analyzed diet intake, fecal 16 S bacteriome, virome, and metabolome in a cross-sectional study in healthy rural and urban Xhosa people (South Africa). Urban Xhosa individuals had higher intakes of energy (urban: 3,578 ± 455; rural: 2,185 ± 179 kcal/d), fat and animal protein. This was associated with lower fecal bacteriome diversity and a shift from genera favoring degradation of complex carbohydrates (e.g., Prevotella) to taxa previously shown to be associated with bile acid metabolism and CRC. Urban Xhosa individuals had higher fecal levels of deoxycholic acid, shown to be associated with higher CRC risk, but similar short-chain fatty acid concentrations compared with rural individuals. Fecal virome composition was associated with distinct gut bacterial communities across urbanization, characterized by different dominant host bacteria (urban: Bacteriodota; rural: unassigned taxa) and variable correlation with fecal metabolites and dietary nutrients. Food and skin microbiota samples showed compositional differences along the urbanization gradient. Rural-urban dietary transition in South Africa is linked to major changes in the gut microbiome and metabolome. Further studies are needed to prove cause and identify whether restoration of specific components of the traditional diet will arrest the accelerating rise in NCDs in Sub-Saharan Africa.

Integrating a web-based, patient-administered assessment into primary care for HIV-infected adults.

Providers routinely under diagnose at risk behaviors and outcomes, including depression, suicidal ideation, substance abuse, and poor medication adherence. To address this, we developed a web-based, self-administered patient-reported assessment tool and integrated it into routine primary care for HIV-infected adults. Printed results were delivered to providers and social workers immediately prior to patient appointments. The assessment included brief, validated instruments measuring clinically relevant domains including depression, substance use, medication adherence, and HIV transmission risk behaviors. Utilizing the Institute for Healthcare Improvement's Plan-Do-Study-Act (PDSA) approach to quality improvement, we addressed issues with clinic flow, technology, scheduling, and delivery of assessment results with the support of all levels of clinic staff. We found web-based patient-reported assessments to be a feasible tool that can be integrated into a busy multi-provider HIV primary care clinic. These assessments may improve provider recognition of key patient behaviors and outcomes. Critical factors for successful integration of such assessments into clinical care include: strong top-level /ort from clinic management, provider understanding of patient-reported assessments as a valuable clinical tool, tailoring the assessment to meet provider needs, communication among clinic staff to address flow issues, timeliness of delivery, and sound technological resources.

Exploring the impact of traumatic brain injury on the older couple: 'yes, but how much of it is age, I can't tell you ...'.

PRIMARY OBJECTIVE: To qualitatively explore the partner relationships of older couples faced with traumatic brain injury (TBI). RESEARCH DESIGN: Qualitative analysis comparing individuals with TBI and a comparison group. METHODS AND PROCEDURES: Twenty-one individuals were interviewed using a semi-structured format focusing on various aspects of their partner relationship. A qualitative analysis of transcripts identified general themes. MAIN OUTCOMES AND RESULTS: Variability of relationship experiences (relationship relatedness and persistence of the partnership) was shown across groups. Aspects of relationship commitment to the partnership were revealed. Many individuals with TBI and their partners attributed various relationship changes to ageing and age-related issues and not to the TBI. CONCLUSIONS: These findings suggest that the effects of TBI are not clearly distinguished from age-related causes for change in the partners and their relationship. Older couples' experiences may be different from those of younger couples impacted by TBI, in the areas of sexuality, inter-personal support and role functions.

Complete genome sequence of Salmonella enterica serovar Typhimurium LT2.

Salmonella enterica subspecies I, serovar Typhimurium (S. typhimurium), is a leading cause of human gastroenteritis, and is used as a mouse model of human typhoid fever. The incidence of non-typhoid salmonellosis is increasing worldwide, causing millions of infections and many deaths in the human population each year. Here we sequenced the 4,857-kilobase (kb) chromosome and 94-kb virulence plasmid of S. typhimurium strain LT2. The distribution of close homologues of S. typhimurium LT2 genes in eight related enterobacteria was determined using previously completed genomes of three related bacteria, sample sequencing of both S. enterica serovar Paratyphi A (S. paratyphi A) and Klebsiella pneumoniae, and hybridization of three unsequenced genomes to a microarray of S. typhimurium LT2 genes. Lateral transfer of genes is frequent, with 11% of the S. typhimurium LT2 genes missing from S. enterica serovar Typhi (S. typhi), and 29% missing from Escherichia coli K12. The 352 gene homologues of S. typhimurium LT2 confined to subspecies I of S. enterica-containing most mammalian and bird pathogens-are useful for studies of epidemiology, host specificity and pathogenesis. Most of these homologues were previously unknown, and 50 may be exported to the periplasm or outer membrane, rendering them accessible as therapeutic or vaccine targets.

Time course changes in IGFBP-1 after treadmill exercise and postexercise food intake in rats.

Prolonged exercise increases circulating insulin-like growth factor binding protein-1 (IGFBP-1) in humans and animals, but its physiological significance is unknown. This study examined 1) time-course changes in plasma IGFBP-1 and hepatic IGFBP-1 mRNA expression after exercise, 2) changes in IGFBP-1 in relation to plasma glucose, insulin, and IGF-I, and 3) the impact of feeding a postexercise meal on the IGFBP-1 response. Food-deprived male rats were vigorously run on a treadmill and compared with nonexercised controls at 15 min and 1, 4, 8, and 12 h after exercise. Circulating insulin concentrations in exercised rats were lower than in controls at 15 min and 1 h, whereas plasma glucose and IGF-I remained unaffected. Circulating and hepatic expression of IGFBP-1 was markedly increased above that of controls at 15 min, 1 h, and 12 h. In a separate experiment, one-half of the exercised animals received a nutritionally complete meal immediately after the experimental run. The meal elevated plasma insulin and glucose concentrations at 15 min and 1 h. Despite this change in nutritional status, serum IGFBP-1 concentrations and hepatic IGFBP-1 abundance remained elevated at 15 min and 1 h. These results demonstrate that the IGFBP-1 response to a single bout of treadmill exercise is short in duration and independent of insulin, glucose, and amino acid availability.

Leucine supplementation enhances skeletal muscle recovery in rats following exercise.

This study was designed to determine the ability of leucine to enhance muscle recovery after exercise. Male rats (200 g) were divided into five groups: sedentary, food-deprived (SF); exercised, food-deprived (EF); exercised, fed a carbohydrate meal (EC); exercised, fed a leucine meal (EL); and exercised, fed a combination of carbohydrate and leucine (ECL). All meals were administered by oral gavage immediately following exercise. EC and ECL meals were isocaloric and provided 15% of daily energy intake. EL and ECL meals each provided 270 mg leucine. Rats ran on a motor-driven treadmill for 2 h at 36 m/min and were killed 1 h postexercise. Plasma glucose and insulin were measured, and the gastrocnemius and plantaris muscles were excised as a unit to determine glycogen levels and the fractional rate of skeletal muscle protein synthesis (Ks). Exercise did not alter plasma glucose or insulin. In contrast, prolonged exercise reduced muscle glycogen (-51%) and Ks (-18%). Refeeding a combination of carbohydrate and leucine increased plasma insulin relative to the EF and SF groups and produced complete recovery of muscle Ks and glycogen to values not different from those in SF rats. Feeding leucine alone restored Ks to that in the SF group without affecting plasma glucose or insulin concentrations. Feeding carbohydrate alone enhanced the rate of glycogen repletion compared to the EF group, concomitant with increases in plasma glucose and insulin. The degree of glycogen recovery correlated with plasma insulin concentrations (r = 0.58, P < 0.05). These data suggest that leucine stimulates muscle protein synthesis following exercise, independent of increased plasma insulin. This is the first demonstration that orally administered leucine stimulates recovery of skeletal muscle protein synthesis after exercise.

Growth hormone promotes somatic and skeletal muscle growth recovery in rats following chronic protein-energy malnutrition.

The efficacy of recombinant human growth hormone (GH) and/or a diet enriched in protein and energy to improve growth recovery following prolonged malnutrition was examined in male rats food-restricted from birth until 120 d of age. At d 121, restricted rats were randomly assigned to recovery groups receiving either a control or enriched diet with or without daily subcutaneous injections of GH. Rats were killed after 16 or 47 d of recovery. At d 16, GH treatment stimulated liver, heart, plantaris, soleus, carcass and body weight gain and inhibited fat gain when compared to recovery controls. Rats receiving GH also exhibited the highest serum insulin-like growth factor-I (IGF-I) concentrations and total muscle protein. At d 47, GH effects on body and muscle recovery were minimal, and differences among recovery groups in serum IGF-I concentration and total muscle protein were no longer present. Consumption of an enriched diet increased fat pad and liver mass, but did not promote muscle recovery. There were no differences among treatment groups in skeletal muscle IGF-I mRNA levels at d 16 or 47. In summary, GH had positive effects on somatic and skeletal muscle growth early in the recovery process, possibly via endocrine IGF-I-stimulated protein accretion. In contrast, the enriched diet promoted fat deposition with no impact on skeletal muscle growth recovery.

Response of the IGF-I system to prolonged undernutrition and its involvement in somatic and skeletal muscle growth retardation in rats.

We examined the response of the IGF-I system to prolonged undernutrition and its involvement in somatic and skeletal muscle growth retardation. Male rats were food-restricted to 50% of freely-fed controls (C) from birth to 120 days postpartum. Serum and tissues were collected at d 50 and d 120 postpartum. Somatic growth of food-restricted animals (R) was proportional to food intake while organ and tissue growth was disproportionate. Skeletal muscle DNA content and synthesis rates were depressed by undernutrition and DNA synthesis decreased with age. Food-restriction abated serum IGF-I concentrations, serum IGFBP-3 expression and hepatic IGF-I mRNA levels at d 50. Conversely, at d 120, hepatic IGF-I mRNA levels in R were similar to C despite decreased serum IGF-I concentrations and serum IGFBP-3 expression. Hepatic IGFBP-1 and -2 mRNA expression in R was increased at both d 50 and 120, and hepatic IGFBP-4 mRNA expression was elevated on d 120 compared to C. Gastrocnemius IGF-I mRNA levels in R were not different from C at either d 50 or 120. These results suggest that hepatic IGF-I sensitivity to undernutrition decreases with increasing age, and endocrine regulation of IGF-I following adaptation to chronic undernutrition occurs post-transcriptionally. Further, local production of IGF-I in skeletal muscle does not appear to be responsible for the marked decline in muscle DNA synthesis, for skeletal muscle IGF-I mRNA expression was not altered by undernutrition.

An in vitro system for studying osteointegration of dental implants utilizing cells grown on dense hydroxyapatite disks.

A proposed in vitro system is described where chick osteoblasts are cultured on the flat surfaces of dense, nonporous HA disks to facilitate the study of bone formation at the cell-HA interface. During early bone formation cell-coated HA disks were retrieved, fixed with buffered 2% glutaraldehyde, and embedded in epon/araldite. The underlying HA disks were demineralized in diluted acid, and the intact cell-HA interfaces were re-embedded and thin sectioned for routine transmission electron microscopy. Morphologic studies indicated that osteoblasts proliferated and formed nodules of cells on the surfaces of HA disks. With increasing time in culture, they deposited orthogonally packed collagen fibrils between the cell layers that were enveloped by electron-dense mineralized globules. Eventually, small spicules of mineralized HA formed along collagen fibrils. An electron-dense layer about 50 nm thick was observed on the surface of the HA disks. Biochemical studies indicated that cell proliferation, as judged by 3H-thymidine uptake, increased rapidly during the first 3 days, reached a maximum around 6 days, and then declined by 12 days in culture. AP activity and collagen synthesis, as determined by 3H-hydroxyproline formation, increased as cellular proliferation declined. Mineralization, as judged by 45Ca uptake and spicule formation, occurred, as expected, following the increase in AP activity and deposition of densely packed collagen fibrils. Thus, all morphological and biochemical parameters studied indicate that the proposed in vitro system is reproducible and can facilitate the study of the osteointegration of HA-coated implants.

Availability of eIF4E regulates skeletal muscle protein synthesis during recovery from exercise.

We examined the association of the mRNA cap binding protein eIF4E with the translational inhibitor 4E-BP1 in the acute modulation of skeletal muscle protein synthesis during recovery from exercise. Fasting male rats were run on a treadmill for 2 h at 26 m/min and were realimented immediately after exercise with either saline, a carbohydrate-only meal, or a nutritionally complete meal (54.5% carbohydrate, 14% protein, and 31.5% fat). Exercised animals and nonexercised controls were studied 1 h postexercise. Muscle protein synthesis decreased 26% after exercise and was associated with a fourfold increase in the amount of eIF4E present in the inactive eIF4E.4E-BP1 complex and a concomitant 71% decrease in the association of eIF4E with eIF4G. Refeeding the complete meal, but not the carbohydrate meal, increased muscle protein synthesis equal to controls, despite similar plasma concentrations of insulin. Additionally, eIF4E.4E-BP1 association was inversely related and eIF4E.eIF4G association was positively correlated to muscle protein synthesis. This study demonstrates that recovery of muscle protein synthesis after exercise is related to the availability of eIF4E for 48S ribosomal complex formation, and postexercise meal composition influences recovery via modulation of translation initiation.

Preexercise meal composition alters plasma large neutral amino acid responses during exercise and recovery.

This study was designed to determine the effect of ingesting three preexercise meals on energy metabolism during exercise and recovery and to relate metabolic perturbations to subjective and objective measurements associated with central fatigue. Twelve subjects consumed isoenergetic meals consisting of oat, wheat, or corn cereals 90 min before cycling. A fasting trial served as the control. Blood samples and cognitive function, perceived hunger, and sleepiness measurements were obtained before and after feeding and during recovery when self-selected food intake was also measured. After meal ingestion, plasma insulin was lower for oat than for wheat or corn whereas the ratio of tryptophan to large neutral amino acids (LNAAs) for corn was less than for all others. During exercise, the tryptophan-LNAA ratio increased from preexercise values for the fasting and wheat trials, but exercise performance was unaffected. During recovery, tryptophan:LNAA increased from postexercise values in fasting trials. Also, hunger and fatigue ratings were greater in fasted subjects, but self-selected food intake measured at the end of the recovery period was not different among groups. We conclude that preexercise meal consumption affected tryptophan:LNAA before, during, and after exercise, but these changes were not sufficient to alter physical and cognitive performance.

Oat, wheat or corn cereal ingestion before exercise alters metabolism in humans.

This study was designed to determine metabolic and physical performance responses to ingestion of pre-exercise meals with different macronutrient and fiber profiles. Twelve physically active subjects (6 males and 6 females) were used to investigate the metabolic and physical performance consequences of consuming pre-exercise meals consisting of oat, corn, or wheat cereals. A fasting trial served as the control, and all subjects received each treatment in a Latin-square design. Blood samples were drawn before and 85 min after meal ingestion, during 90 min of cycling exercise (60% VO2peak), after a 6.4 km performance ride, and during 60 min of recovery. Expired air samples were collected to determine nutrient utilization. Resting carbohydrate oxidation rates and plasma insulin concentrations after oat ingestion were less than after wheat, and corn and wheat ingestion, respectively (P < 0.05). During exercise, the change in plasma glucose from pre-exercise was greater after consuming wheat and corn compared with oat (P < 0.05), and it was inversely related to pre-exercise plasma insulin concentration (r = -0.55, P = 0.0001). Plasma free fatty acid concentrations were inversely related to plasma lactate concentrations (r = -0.58, P = 0.0001). Free fatty acid concentrations and fat oxidation were greater in fasting trials than all others, but performance ride times did not differ among treatments. Plasma branched-chain amino acid concentrations resembled their respective meal profiles throughout exercise, the performance ride, and recovery. These results indicate that pre-exercise meal composition can influence glucose homeostasis during early exercise and plasma branched-chain amino acid concentrations over a substantial range of metabolic demands.

Food restriction and lysine supplementation alter growth, RNA, DNA, and protein contents of skeletal muscle.

Efficacy of supplementing total protein or a limiting amino acid to maintain muscle development during food restriction was examined in growing rats. Male rats weighing 108 +/- 8 g were assigned to one of five diet groups plus an initial group. Animals were fed either a wheat gluten-based diet or the wheat gluten-based diet supplemented with adequate levels of lysine. These diets were fed ad libitum or at a 75% restricted level. One restricted group was fed a high gluten diet designed to meet lysine requirements but at the restricted energy level. Rats were fed these diets for 6 weeks. Lysine supplementation resulted in higher levels of protein, RNA, and DNA in skeletal muscle and liver of animals fed ad libitum. Food restriction resulted in loss of protein and RNA from liver and skeletal muscle and lower ratios of protein/DNA. Initial DNA contents of plantaris and soleus muscles were not affected by food restriction; however, hepatic DNA was reduced. Supplementation of lysine to animals restricted in food intake failed to improve growth of skeletal muscle or liver, and resulted in lower protein contents in liver (11%), plantaris (6%), and soleus (38%). Increasing total protein intake for the animals with the restricted intake resulted in a higher RNA/DNA ratio without a parallel increase in protein in liver or muscle. This study demonstrates that during severe food restriction skeletal muscle DNA is preserved which maintains high potential for growth recovery. This study also indicates that during severe, prolonged food restriction supplementation of protein or limiting amino acids results in lower tissue protein contents.

The effects of chlorhexidine on the attachment and growth of cultured human periodontal cells.

The purpose of this investigation was to evaluate the effects of chlorhexidine (CHX) on the attachment and growth of human gingival fibroblasts and periodontal ligament cells using an in vitro system where periodontal cells were grown on root surfaces treated previously with CHX. Our results indicate that the attachment of periodontal cells onto root surfaces was not adversely affected when roots were treated for 15 minutes with up to 0.12% CHX. However, cell attachment and morphology were adversely altered with prior 0.2 to 2.0% CHX treatment. The cells appeared round and retracted from roots treated with 0.2% CHX. With 2% CHX treatment, the cells exhibited a foamy appearance in which most of the cytoplasm seemed to have been extracted from the cells. Although 0.12% CHX treatment did not adversely affect the attachment of periodontal cells onto roots, direct exposure to as little as 0.01% CHX caused a 90% reduction in 3H-thymidine incorporation by cultured gingival fibroblasts. We conclude that although 0.12% CHX did not inhibit the attachment of cultured periodontal cells to pretreated roots, direct exposure of cells to much lower concentrations of CHX (0.0025 to 0.01%) caused a dose-dependent inhibition of growth.

Fibroblastic growth and attachment on hydroxyapatite-coated titanium surfaces following the use of various detoxification modalities. Part I: Noncontaminated hydroxyapatite.

Hydroxyapatite-coated titanium alloy test strips were treated with chlorhexidine gluconate, stannous fluoride, citric acid, tetracycline HCl, polymyxin B, hydrogen peroxide, and a plastic Cavitron tip: untreated sterile strips served as controls. The strips were incubated with cultured human gingival and periodontal ligament fibroblasts. Image analysis of three photomicrographs of each test strip (original magnification x350) indicated that the tetracycline HCl treatment resulted in significantly greater cellular surface area coverage compared with the other treatments. Citric acid and the plastic Cavitron tip also stimulated cell attachment, although the results from the Cavitron tip were not significantly different from citric acid or the other treatment groups. The remainder of the modalities and the untreated cellular controls experienced similar cellular coverage.

Fibroblastic growth and attachment on hydroxyapatite-coated titanium surfaces following the use of various detoxification modalities. Part II: Contaminated hydroxyapatite.

This study evaluated the ability of various chemotherapeutic and mechanical modalities to detoxify endotoxin-contaminated hydroxyapatite-coated dental implant surfaces as determined by the early attachment and growth of human gingival fibroblasts. Hydroxyapatite-coated test strips were contaminated with purified outer membranes of Escherichia coli and treated with citric acid, hydrogen peroxide, stannous fluoride, chlorhexidine gluconate, tetracycline HCl, polymyxin B, a plastic sonic scaler tip, or left untreated (contaminated and sterile controls). Human gingival fibroblasts were then seeded onto the test strips and incubated for 48 hours. The citric acid-treated strips showed greater cell growth than the other treatments. The plastic sonic scaler tip and the polymyxin B-treated samples exhibited greater cell coverage than the sterile control specimens. The use of citric acid and/or a modified plastic sonic scaler tip may be a valuable adjunct when surgical repair of an ailing hydroxyapatite-coated dental implant is contemplated.

Alterations in cell morphology and cytoskeletal proteins in gingival fibroblasts exposed to a Bacteroides gingivalis extract.

A soluble sonic extract (SSE) from Bacteroides gingivalis caused a dose-dependent inhibition of gingival fibroblast growth, reduced cell attachment and altered cell morphology. Most of its cytotoxic activity was destroyed by heating, indicating that the factor(s) was a protein rather than endotoxin. Cells, grown in the presence of, or on, root surfaces pretreated with 100-200 micrograms SSE/ml, partially retracted from the substratum and exhibited extensive surface blebbing and finger-like protrusions. Immunofluorescent staining showed that the morphological effects of Bacteroides gingivalis SSE are directed specifically at actin stress fibers and not microtubules of the cytoskeleton. Exposure to the SSE resulted in a dramatic relocalization of the bulk of F-actin from a fibrous form to a non-aggregated diffuse form. Disorganization of actin stress fibres occurred at concentrations of SSE that inhibited cell growth, but preceded any observable changes in cell attachment or morphology. The microtubular network remained intact, although it stained less intensely than that of controls. By contrast, Bacteroides intermedius SSE did not significantly influence growth, alter cellular morphology or affect the two cytoskeletal proteins.

Whole body and plasma protein synthesis in exercise and recovery in human subjects.

The effect of 4 h of exercise at 40% of maximal oxygen consumption (VO2 max) on protein metabolism was assessed in normal volunteers maintained on a diet containing 42 kcal.kg-1.day-1 and either 0.9 or 2.5 g protein.kg-1.day-1. Primed constant infusions of [1,2-13C]-leucine and [15N]glycine enabled the quantitation of whole body protein turnover and also the fractional synthetic rates (FSR) of albumin, fibrinogen, and fibronectin. In subjects who did not exercise, the fractional synthetic rates (%/day) on normal and high-protein intakes, respectively, were as follows: albumin, 10 +/- 1 and 9 +/- 1; fibrinogen, 21 +/- 3 and 18 +/- 1; and fibronectin, 31 +/- 3 and 34 +/- 3. Neither exercise nor recovery had an effect of whole body protein turnover or on albumin FSR, but the FSR of fibronectin was significantly elevated at the end of exercise, and fibrinogen was significantly elevated in recovery. Dietary protein intake had no major effect on the response to exercise. Thus, in response to exercise, there is a stimulation of the synthesis of some acute phase proteins, which may be a mechanism whereby nitrogen resulting from muscle protein breakdown is spared.

Use of ketamine-HC1 anesthesia in studies of chylomicron-triglyceride metabolism in the rat.

Ketamine with 10% acepromazine (Km/Ac) was evaluated for use in an investigation of plasma chylomicron-triglyceride clearance in rats. Clearance rate and the half-life of radiolabeled (14C) chylomicron triglycerides plus tissue uptake of 14C-fatty acids were equal in Km/Ac anesthetized and non-anesthetized rats. Km/Ac was found to be a suitable anesthesia in rats for the study of plasma chylomicron-triglyceride clearance.

Suppression of fibroblast growth by Bacteroides gingivalis endotoxin is not reduced by serum lipoproteins.

Previous studies indicated that Bacteroides and E. coli endotoxins caused a dose-dependent inhibition of human fibroblast growth. However, these endotoxins were relatively weak inhibitors of growth. Since cells were grown with serum, we questioned whether serum lipoproteins, which lessen endotoxin cytotoxicity in vivo, reduced the growth inhibitory effects of endotoxins in vitro. To determine whether serum lipoproteins reduced the growth inhibitory effects of endotoxins, logarithmically growing human periodontal cells were incubated with endotoxin and high density (HDL) or low density lipoprotein (LDL). Neither HDL nor LDL significantly reduced the initial growth inhibitory effects of B. gingivalis or E. coli endotoxins, as judged by 3H-thymidine incorporation. Even with prolonged exposure of up to 10 days in culture, HDL did not ameliorate growth inhibition by endotoxin, as determined by direct cell counts. We conclude that serum lipoproteins do not provide any significant protective effects against fibroblast growth inhibition by endotoxins in vitro.