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Biomedical subjects

T Graham

Publications and source records attributed to T Graham.

At least 19 recordsLinked to original sources
PubMed2002

The effect of diet fed to lambs on subsequent development of Trichostrongylus colubriformis larvae in vitro and on pasture.

Contrasting herbage diets were fed to lambs to evaluate their effect on subsequent development of Trichostrongylus colubriformis larvae in faeces and on pasture. The diets had either no condensed tannin (CT), lucerne (Medicago sativa cv. Otaio), white clover (Trifolium repens cv. Tahora), or had moderate to high concentrations of CT, sulla (Hedysarum coronarium cv. Grassland Aokau), Lotus corniculatus (cv. Grasslands Goldie), L. pedunculatus (cv. Grassland Maku), Dorycnium pentophyllum, and Dorycnium rectum. Trials were carried out in summer (warm) and in autumn (cool and moist). In summer, egg viability was evaluated in vitro with egg hatch and larval development assays. In both seasons faeces were placed on pasture to compare recovery of eggs and larvae from faeces and larvae from herbage on the high and low fertility farmlets on the AgResearch Ballantrae Hill Country Research Station. D. rectum and D. pentophyllum diets decreased (P<0.01) egg hatching and larval development in laboratory assays relative to other diets. In summer, the number of larvae recovered from faeces placed on pasture was far greater (P<0.001) if the lambs had been fed lucerne than any other diet, whereas recovery was always lowest from faeces of sheep fed D. rectum and D. pentophyllum. Although dietary differences were lower in autumn than in summer, larval recoveries were lower (P<0.05) from faeces of lambs fed D. rectum and L. corniculatus than from white clover, lucerne and sulla diets. This study indicates that the diet of the host can have a significant impact on egg hatching and the subsequent development of T. colubriformis larvae in the laboratory and in the field. In particular, D. rectum consistently reduced T. colubriformis development. Effects measured in vitro generally under-estimated effects measured under field conditions.

Animal Feed↗
PubMed2001

Initial ethanol exposure results in decreased heart rate variability in ethanol-naive rhesus monkeys.

Ethanol's effects on heart rate variability may contribute to the increased cardiac disease and mortality observed in alcoholics. We assessed cardiac response to ethanol in seven previously ethanol-naive monkeys given a standard dose of ethanol, or saline. Ethanol exposure reduced cardiac signal complexity [mean+/-S.D. (ethanol: Hurst parameter=0.39+/-0.02; saline: Hurst parameter=0.32+/-0.06)] and increased the spectral exponent (ethanol: beta=1.36+/-0.35; saline: beta=1.12+/-0.35) when compared to saline, while heart rate itself was unaffected (saline: interbeat interval=303.57+/-24.57; ethanol: interbeat interval=308.14+/-20.45). Taken together with data that show autonomic disregulation in alcoholics, these findings provide further evidence of deleterious ethanol effects on cardiac signal dynamics.

Animals↗
PubMed2001

Gender differences in carbohydrate loading are related to energy intake.

We demonstrated that female endurance athletes did not increase their muscle glycogen concentration after an increase in the dietary carbohydrate intake (58 --> 74%), whereas men did (Tarnopolsky MA, SA Atkinson, SM Phillips, and JD McDougall, J Appl Physiol 78: 1360-1368, 1995). This may have been related to a lower energy or carbohydrate intake by the women or due to an inherent gender difference in glycogen storage capacity. We examined whether well-trained men (n = 6) and women (n = 6) increased muscle glycogen concentration after an increase in both the relative (58 --> 75%) and absolute energy and carbohydrate intake and whether potential gender differences were related to muscle hexokinase enzyme activity. Subjects were randomly allocated to three diets [Hab, habitual; CHO, high carbohydrate (75%); and CHO + E, extra energy + CHO ( upward arrow~34%)] for a 4-day period before a muscle biopsy for analysis of total and pro- and macroglycogen and hexokinase activity. Total glycogen concentration was higher for the men on the CHO and CHO + E trials compared with Hab (P < 0.05), whereas women increased only on the CHO + E trial compared with Hab (P < 0.05). There were no gender differences in the proportion of pro- and macroglycogen or hexokinase activity. A low energy intake may explain the previously reported lower capacity for women to glycogen load compared with men.

Adult↗
PubMed2001

Caffeine ingestion decreases glucose disposal during a hyperinsulinemic-euglycemic clamp in sedentary humans.

The purpose of this investigation was to examine the effect of caffeine (an adenosine receptor antagonist) on whole-body insulin-mediated glucose disposal in resting humans. We hypothesized that glucose disposal would be lower after the administration of caffeine compared with placebo. Healthy, lean, sedentary (n = 9) men underwent two trial sessions, one after caffeine administration (5 mg/kg body wt) and one after placebo administration (dextrose) in a double-blind randomized design. Glucose disposal was assessed using a hyperinsulinemic-euglycemic clamp. Before the clamp, there were no differences in circulating levels of methylxanthines, catecholamines, or glucose. Euglycemia was maintained throughout the clamp with no difference in plasma glucose concentrations between trials. The insulin concentrations were also similar in the caffeine and placebo trials. After caffeine administration, glucose disposal was 6.38 +/- 0.76 mg/kg body wt compared with 8.42 +/- 0.63 mg/kg body wt after the placebo trial. This represents a significant (P < 0.05) decrease (24%) in glucose disposal after caffeine ingestion. In addition, carbohydrate storage was 35% lower (P < 0.05) in the caffeine trial than in the placebo trial. Furthermore, even when the difference in glucose disposal was normalized between the trials, there was a 23% difference in the amount of carbohydrate stored after caffeine administration compared with placebo administration. Caffeine ingestion also resulted in higher plasma epinephrine levels than placebo ingestion (P < 0.05). These data support our hypothesis that caffeine ingestion decreases glucose disposal and suggests that adenosine plays a role in regulating glucose disposal in resting humans.

Administration, Oral↗
PubMed2001

Influence of close-up dry period protein supplementation on productive and reproductive performance of Holstein cows in their subsequent lactation.

Holstein cows on a commercial dairy were assigned to close-up dry groups and offered an 11.7% crude protein (CP) ration based on corn silage, alfalfa cubes, oat hay, corn, and barley grain without (Control; C) or with (Supplemented; S) 0.8 kg/d per cow of a high CP supplement of SoyPass, distillers dried grains, ring dried blood meal, feather meal, and corn gluten meal. Heifers (C: 37, S: 44) and mature cows (C: 96, S: 81) were allocated to one of four groups based upon their time in the close-up groups (i.e., 1 to 4, 5 to 8, 9 to 12, and 13 to 19 d) within parity (i.e., heifers or mature) for statistical analysis. Full lactation means of all response parameters for cows confirmed to be pregnant that completed a lactation (i.e., lactating at 305 d in milk or dried off before 305 d in milk but not culled; C: 28, S: 23 for heifers and C: 48, S: 43 for mature cows) were analyzed by ANOVA. Lactation curves were evaluated by parallel curve analysis to assess differences in lactation curve shape, and curve separation, due to treatments. Protein supplementation had no impact on full-lactation milk or milk component yields of heifers, determined by ANOVA, although parallel curve analysis showed higher milk and milk protein yield with protein supplementation. As the number of days cows spent consuming their assigned close-up dry rations increased, heifers produced more milk, milk fat and milk protein, although the maximum yield for milk and milk protein occurred for those fed close-up rations for 9 to 12 d. For mature cows, neither time close up or close-up period protein supplementation influenced any mean response parameter, by ANOVA, although parallel curve analysis showed higher milk and protein yield for supplemented cows as time close up increased. Overall, results suggest the optimum close-up period length was 9 to 12 d, with a protein content intermediate between 11.7 and 14.4% of DM, for heifers. In contrast, results do not support any substantive benefit of a close up period, or protein contents above 11.7%, for mature cows.

Analysis of Variance↗
PubMed2001

Increasing revenue through A/R recovery, revenue-cycle redesign.

After experiencing operating losses of more than $15 million and a growing number of days in accounts receivable and payment denials, Capital Health System implemented a multidisciplinary recovery program to redesign its revenue cycle. The system reorganized its business office staff, outsourced some collection activities, and stepped up its efforts to review coding, analyze billing errors and edits, update its charge description master, and track payment denials. Although this work is ongoing, during the initial revenue-cycle redesign, the system increased its cash flow by more than $30 million and increased patient-service revenue by 7 percent annually between January 1999 and July 2001. Capital has received more than $10 in new collected revenue for every dollar spent on accounts-receivable recovery and revenue enhancement.

Accounts Payable and Receivable↗
PubMed2000

omega-3 fatty acids decrease endothelial adhesion of human colorectal carcinoma cells.

BACKGROUND: Diets rich in omega-3 fatty acids have been shown to decrease both the initiation and promotion of colon carcinogenesis although their effect on hepatic metastasis formation is less well understood. Since adhesion of human colorectal carcinoma (HCRC) cells to hepatic endothelial cells is an important step in the metastatic cascade, the effect of membrane omega-3 fatty acid alterations on endothelial cell adhesion was studied. MATERIALS AND METHODS: CX-1 cells, a moderately differentiated HCRC cell line known to produce hepatic metastases in an athymic mouse intrasplenic injection model, were used. Cells were grown in omega-3 fatty acid-enriched medium and membrane-free fatty acid modifications confirmed with gas chromatography. Both human umbilical vein and hepatic sinusoidal endothelial cells were used in the binding assays. Adhesion assays were performed in a standard fashion using (51)Cr-labeled cells to tumor necrosis factor (TNF)-stimulated endothelial cell monolayers. Immunohistochemical analysis was performed for sialyl-Lewis(x), the receptor involved in endothelial adhesion on the surface of control and fatty acid-modified cells. RESULTS: Gas chromatographic analysis confirmed membrane fatty acid modification of CX-1 cells by growth in docosahexanoic acid (omega-3) (4.761 nmol/10(6) cells vs 0.057 nmol/10(6) cells for controls). Binding of CX-1 to both human umbilical vein and hepatic sinusoidal endothelial cells decreased from 38.4 +/- 0.44 to 11.58 +/- 0.87% (P < 0.01). Immunocytochemical analysis showed a decrease in sialyl-Lewis(x) expression with omega-3 treatment. CONCLUSIONS: These data indicate that omega-3 fatty acids may also be protective against the formation of hepatic metastases. The mechanism for this may be decreased endothelial cell adhesion which in turn may be due to decreased expression of the endothelial receptor sialyl-Lewis(x).

Animals↗
PubMed1999

Dose rate-dependent marrow toxicity of TBI in dogs and marrow sparing effect at high dose rate by dose fractionation.

We evaluated the marrow toxicity of 200 and 300 cGy total-body irradiation (TBI) delivered at 10 and 60 cGy/min, respectively, in dogs not rescued by marrow transplant. Additionally, we compared toxicities after 300 cGy fractionated TBI (100 cGy fractions) to that after single-dose TBI at 10 and 60 cGy/min. Marrow toxicities were assessed on the basis of peripheral blood cell count changes and mortality from radiation-induced pancytopenia. TBI doses studied were just below the dose at which all dogs die despite optimal support. Specifically, 18 dogs were given single doses of 200 cGy TBI, delivered at either 10 (n=13) or 60 (n=5) cGy/min. Thirty-one dogs received 300 cGy TBI at 10 cGy/min, delivered as either single doses (n=21) or three fractions of 100 cGy each (n=10). Seventeen dogs were given 300 cGy TBI at 60 cGy/min, administered either as single doses (n=5) or three fractions of 100 cGy each (n=10). Within the limitations of the experimental design, three conclusions were drawn: 1) with 200 and 300 cGy single-dose TBI, an increase of dose rate from 10 to 60 cGy/min, respectively, caused significant increases in marrow toxicity; 2) at 60 cGy/min, dose fractionation resulted in a significant decrease in marrow toxicities, whereas such a protective effect was not seen at 10 cGy/min; and 3) with fractionated TBI, no significant differences in marrow toxicity were seen between dogs irradiated at 60 and 10 cGy/min. The reduced effectiveness of TBI when a dose of 300 cGy was divided into three fractions of 100 cGy or when dose rate was reduced from 60 cGy/min to 10 cGy/min was consistent with models of radiation toxicity that allow for repair of sublethal injury in DNA.

Animals↗
PubMed1999

Gender differences in cardiovascular and catecholamine responses to cold-air exposure at rest.

Metabolic and cardiovascular responses were examined in 8 men and 9 women during 2 hrs of sitting at rest in 5 degrees C. The men and women had similar body fatness and both groups responded with similar changes relative to control in cardiac output, blood pressure, total peripheral resistance, VO2, respiratory exchange ratio, and rectal temperature. However, greater increases in stroke volume and decreases in heart rate and skin temperature were observed in men compared to women (p < 0.05). The contribution of CHO and fat to the total energy expended differed (p < 0.05) between genders; the CHO:fat ratio was 47:53 in men and 36:64 in women. No gender differences could be observed in plasma catecholamines. It is concluded that there are striking cardiovascular and metabolic gender differences in response to cold stress which cannot be accounted for by body fatness or catecholamine responses.

Adrenergic alpha-Agonists↗
PubMed1999

Muscle glycogen accumulation after a marathon: roles of fiber type and pro- and macroglycogen.

Muscle glycogen remains subnormal several days after muscle damaging exercise. The aims of this study were to investigate how muscle acid-soluble macroglycogen (MG) and acid-insoluble proglycogen (PG) pools are restored after a competitive marathon and also to determine whether glycogen accumulates differently in the various muscle fiber types. Six well-trained marathon runners participated in the study, and muscle biopsies were obtained from the vastus lateralis of the quadriceps muscle before, immediately after, and 1, 2, and 7 days (days 1, 2, and 7, respectively) after the marathon. During the race, 56 +/- 3.8% of muscle glycogen was utilized, and a greater fraction of MG (72 +/- 3.7%) was utilized compared with PG (34 +/- 6.5%). On day 2, muscle glycogen and MG values remained lower than prerace values, despite a carbohydrate-rich diet, but they had both returned to prerace levels on day 7. The PG concentration was lower on day 1 compared with before the race, whereas there were no significant differences between the prerace PG concentration and the concentrations on days 2 and 7. On day 2 the glycogen concentration was particularly low in the type I fibers, indicating that local processes are important for the accumulation pattern. We conclude that a greater fraction of human muscle MG than of PG is utilized during a marathon and that accumulation of MG is particularly delayed after the prolonged exercise bout. Furthermore, factors produced locally appear important for the glycogen accumulation pattern.

Adult↗
PubMed1999

The prevalence of verotoxins, Escherichia coli O157:H7, and Salmonella in the feces and rumen of cattle at processing.

Fecal samples collected from cattle at processing during a 1-year period were tested for verotoxins (VT1, VT2), Escherichia coli O157:H7, and Salmonella. Verotoxins were detected in 42.6% (95% CI, 39.8% to 45.4%), E. coli O157:H7 in 7.5% (95% CI, 6.1% to 9.1%), and Salmonella in 0.08% (95% CI, 0.004% to 0.5%) of the fecal samples. In yearling cattle, the median within-lot prevalence (percentage of positive samples within a lot) was 40% (range, 0% to 100%) for verotoxins and 0% for E. coli O157:H7 (range, 0% to 100%) and Salmonella (range, 0% to 17%). One or more fecal samples were positive for verotoxins in 80.4% (95% CI, 72.8% to 86.4%) of the lots of yearling cattle, whereas E. coli O157:H7 were detected in 33.6% (95% CI, 26.0% to 42.0%) of the lots. In cull cows, the median within-lot prevalence was 50% (range, 0% to 100%) for verotoxins and 0% (range, 0% to 100%) for E. coli O157:H7 and Salmonella (range, 0% to 0%). Verotoxins were detected in one or more fecal samples from 78.0% (95% CI, 70.4% to 84.2%) of the lots of cull cows, whereas E. coli O157:H7 were detected in only 6.0% (95% CI, 3.0% to 11.4%) of the lots of cull cows. The prevalence of verotoxins in fecal samples was lower in yearling cattle than in cull cows, whereas the prevalence of E. coli O157:H7 in fecal samples was higher in yearling cattle than in cull cows. The prevalence of E. coli O157:H7 in fecal samples was highest in the summer months. Rumen fill, body condition score, sex, type of cattle (dairy, beef), and distance travelled to the plant were not associated with the fecal prevalence of verotoxins or E. coli O157:H7. The prevalence of verotoxins in fecal samples of cull cows was associated with the source of the cattle. It was highest in cows from the auction market (52%) and farm/ranch (47%) and lowest in cows from the feedlot (31%). In rumen samples, the prevalence of verotoxins was 6.4% (95% CI, 4.2% to 9.4%), and it was 0.8% (95% CI, 0.2% to 2.3%) for E. coli O157:H7, and 0.3% (95% CI, 0.007% to 1.5%) for Salmonella.

Abattoirs↗
PubMed1998

Dose rate-dependent sparing of the gastrointestinal tract by fractionated total body irradiation in dogs given marrow autografts.

PURPOSE: We compared gastrointestinal toxicity of single vs. fractionated total body irradiation (TBI) administered at dose rates ranging from 0.021 to 0.75 Gy/min in a canine model of marrow transplantation. METHODS AND MATERIALS: Dogs were given otherwise marrow-lethal single or fractionated TBI from dual 60Co sources at total doses ranging from 8-18 Gy and delivered at dose rates of 0.021, 0.05, 0.10, 0.20, 0.40, and 0.75 Gy/min, respectively. They were protected from marrow death by infusion of previously stored autologous marrow cells and they were given intensive supportive care posttransplant. The study endpoint was 10-day mortality from gastrointestinal toxicity. Logistic regression analyses were used to jointly evaluate the effects of dose rate, total dose, and delivery regimen on toxicity. RESULTS AND CONCLUSION: With increasing dose rates, mortality increased for either mode of delivery of TBI. With dose rates through 0.10 Gy/min, mortality among dogs given single vs. fractionated TBI appeared comparable. Beginning at 0.20 Gy/min, fractionation appeared protective for the gastrointestinal tract. Results in dogs given TBI at 0.40 and 0.75 Gy/min, respectively, were comparable, and dose fractionation permitted the administration of considerably higher total doses of TBI than were possible after single doses, an increment that was on the order of 4.00 Gy. The data indicate that the impact of fractionating the total dose at high dose rates differs from the effect of fractionation at low dose rates.

Animals↗
PubMed1997

Use of the flagellar H7 gene as a target in multiplex PCR assays and improved specificity in identification of enterohemorrhagic Escherichia coli strains.

PCR products of 1.8 kb were generated with DNAs from all Escherichia coli H7 strains tested by using oligonucleotide primers which flank the fliC gene. Three RsaI digestion profiles of these PCR products were evident on agarose gels; the first occurred with serotype O55:H7, O157:H7, or nonmotile (NM) strains, the second occurred with serotype O1:H7 and O18:H7 strains, and the third occurred with serotype O?:H7, O19:H7, O121:H7, O88:H7, and O156:H7 strains. Despite these differences, the nucleotide sequences of the E. coli E32511 (O157:NM) and U5-41 (O1:H7) fliC genes were 97% homologous. Two PCR primer pairs synthesized on the basis of the E32511 H7 fliC sequence amplified specific DNA fragments from all E. coli H7 strains, but did not amplify DNA fragments from the other bacterial strains. The H7-specific primers were used in combination with other primers which target the Verotoxin 1(VT1) and VT2 genes and the E. coli O157:H7 eaeA gene in multiplex PCR assays. In these assays, vt and eaeA PCR products were observed with DNAs from the majority of EHEC strains and vt, eaeA, and fliC PCR products were observed with DNAs from E. coli O157:H7 or NM strains. Only eaeA PCR products were present with DNA from enteropathogenic E. coli, and only vt PCR products occurred with VT-producing E. coli which are not EHEC. The multiplex PCR assays described allow for the specific identification of E. coli O157:H7 or NM and other EHEC strains.

Adhesins, Bacterial↗