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Biomedical subjects

J M Harper

Publications and source records attributed to J M Harper.

At least 37 records · Page 2Linked to original sources
PubMed1997

Eating frequency in the Nationwide Food Consumption Survey (U.S.A.), 1987-1988.

This study was done to provide basic descriptive data on the variation in meal frequency in the U.S. The data analysed were from the 1987-1988 Nationwide Food Consumption Survey (NFCS), a stratified random sample of American households. Participants were asked to provide one 24-h diet recall and two 1-day diet records. Individuals who were pregnant, lactating, or younger than 19 years old were excluded. If more than one eligible subject per household participated, one subject was selected at random. Of the 4,078 eligible participants, data for 3,182 were complete for all three days and were included in the analyses. On average participants ate 3.47 times daily (SD 0.90). When eating occasions during which 70 or fewer kcal were excluded (tea, coffee, or diet beverages, primarily), the mean was 3.12 (SD 0.74), and over 90% of subjects ate between 1. 50 and 4.49 times daily. The ratio of within- to between-person variance in number of eating times daily was 1.17 (</=70 kcal excluded). The day-to-day variation in an individual's eating frequency was relatively large compared with the between-subject variation, suggesting that data for multiple days are needed to measure an individual's eating frequency with precision.

Adult↗
PubMed1997

Prognostic significance of chromosome 17p deletions in childhood primitive neuroectodermal tumors (medulloblastomas) of the central nervous system.

Deletions in the short arm of chromosome 17 (17p) are the most common genetic abnormality in primitive neuroectodermal tumors of the posterior fossa/medulloblastoma (PNET/Mb). The biological consequences of these deletions are not known for children with PNET/Mb; however, the presence of a tumor suppressor gene located in 17p, distinct from p53, has been implicated in tumorigenesis. Two recent studies suggest that 17p deletions in PNET/Mb are associated with a poor prognosis. To address this question, we identified deletions of chromosome 17p by cytogenetic and/or molecular biology methods in tumor biopsy samples from 56 patients with PNET/Mb. Associations between clinical characteristics or survival outcomes and 17p status were examined by multivariate analysis. Forty-one percent of PNET/Mb cases had a deletion of 17p. No significant association was found between 17p deletion and shorter survival duration or higher metastatic stage. Multivariate analysis did not find independent prognostic significance for 17p deletions after accounting for the effects of significant clinical variables. A larger study of the prognostic value of 17p deletion should be considered; however, clinical use of this factor to distinguish high-risk from standard-risk PNET/Mb populations is not warranted at this time.

Age Factors↗
PubMed1996

Alcohol and smoking in relation to the prevalence of adenomatous colorectal polyps detected at sigmoidoscopy.

Cigarette smoking has been associated with adenomatous polyps of the large bowel but not with increased risk of colorectal cancer. Giovannucci et al recently proposed a hypothesis to explain this inconsistency. A key testable aspect of the hypothesis is that smoking in the distant past increases the risk of large polyps. Questions also remain about the association between colorectal polyps and consumption of alcohol. To address these issues, we examined data from 488 cases with adenomatous polyps and 488 controls. Subjects were members of a prepaid health plan in Los Angeles who had a sigmoidoscopy in 1991-1993. As expected, the adjusted odds of polyps in current smokers compared with never-smokers was increased [odds ratio = 2.43; 95% confidence interval (CI) = 1.56-3.79]. For those who had smoked in the distant past (for example, 30 or more pack-years before 20 years ago), the adjusted odds of an adenoma > or = 1 cm, relative to nonsmokers, was 0.88 (95% CI = 0.23-3.42). The adjusted odds of polyps in those consuming > or = 46 gm per day of alcohol compared with nondrinkers was 1.50 (95% CI = 0.72-3.13). Although imprecise, these data do not support the hypothesis that past smoking increases the risk of large polyps, but our results indicate a weak association between alcohol use and risk of adenomatous polyps.

Adenomatous Polyps↗
PubMed1996

Dietary intake of specific carotenoids and vitamins A, C, and E, and prevalence of colorectal adenomas.

We determined whether intakes of the main dietary carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein plus zeaxanthin, and lycopene) and of vitamins A, C, and E were associated with the prevalence of colorectal adenomas among male and female members of a prepaid health plan in Los Angeles who underwent sigmoidoscopy (n = 488 matched pairs). Participants, ages 50-74 years, completed a 126-item semiquantitative food-frequency questionnaire and a non-dietary questionnaire from 1991 to 1993. In the univariate-matched analysis, alpha-carotene, beta-carotene (with and without supplements), beta-cryptoxanthin, lutein plus zeaxanthin, vitamin A (with and without supplements), and vitamin C (with and without supplements) were associated with a decreased prevalence of colorectal adenomas. After adjustment for intake of calories, saturated fat, folate, fiber, and alcohol, and for current smoking status, body mass index, race, physical activity, and use of nonsteroidal anti-inflammatory drugs, only beta-carotene including supplements was inversely associated with adenomas (odds ratio (OR), 0.6; 95% confidence interval (CI), 0.41.1; trend, P= 0.04; ORs compare highest to lowest quartiles0; vitamin C showed a weaker inverse association (OR, 0.8; 95% CI, 0.5-1.5; trend, P = 0.08); and the remaining compounds were no longer clearly associated with risk. After including beta-carotene with supplements and vitamin C simultaneously in the mutivariate model, the association of beta-carotene with supplements with adenomas was weakened (OR, 0.8; 95% CI, 0.5-1.3; trend P = 0.15), and vitamin C was no longer associated with risk. These data provide only modest support for a protective association of beta-carotene with colorectal adenomatous polyps.

Adenoma↗
PubMed1995

Effects of growth factors and gut regulatory peptides on nutrient uptake in ovine muscle cell cultures.

Effects of gut regulatory peptides and growth factors on the uptake of 2-aminoisobutyric acid (AIB) and 2-deoxy-D-glucose (2-DOG) were examined in differentiated ovine satellite cell cultures. Insulin and insulin-like growth factor I (IGF-I) gave maximal increases of 160-180% of controls for AIB and over 190% for 2-DOG. IGF-I showed half-maximal effects at 0.1-1 nM, and insulin at 1-10 nM. Bovine growth hormone (0.01-100 nM) had no effect. Gastrin, gastric inhibitory polypeptide (GIP), bombesin and somatostatin had no action in either the absence or presence of insulin. In primary cultures epidermal growth factor (EGF) increased the uptake of AIB (133-137%) and 2-DOG (171-176%). In clonal lines, EGF had little effect on nutrient uptake but still simulated protein synthesis.

Aminoisobutyric Acids↗
PubMed1994

Risk factors for calculus formation in patients with renal transplants.

OBJECTIVE: To investigate the risk factors for stone formation in patients with functioning renal transplants in whom renal calculi develop. PATIENTS AND METHODS: Renal calculi developed in six of 178 patients with functioning renal transplants under current review, an incidence of 3%. Risk factors for stone formation were investigated in five of these patients and compared with a randomly selected control group of 41 transplant patients with no stone problems. RESULTS: Patients with transplant calculi typically passed smaller volumes of significantly more concentrated and alkaline urine with greater urinary excretion of uric acid (P < 0.05). Urine calcium excretion was also increased. Crystalluria was present in three of five stone formers compared with two of 25 controls. Overall, metabolic abnormalities included hypocitraturia (75%), hyperparathyroidism (36%), hypophosphataemia (24%) and hypercalcaemia (10%). Urinary infection was common (50%) and urinary output of magnesium and phosphate was at the lower end of normal for all patients. CONCLUSION: These results suggest a multifactorial aetiology for stone formation in renal transplant recipients. Approaches to prevention and management are discussed.

Citrates↗
PubMed1994

The divine triangle: God in the marital system of religious couples.

Incorporating both Bowenian and structural approaches, this article offers a constructivist view for dealing with religious belief systems of couples. After exploring the evolving process by which couples mutually define an ongoing triadic relationship with their Deity, different triangular processes from an integrated structural and Bowenian perspective are presented. This view is evaluative in terms of the triangulation process rather than the belief systems themselves, and, as such, it can be useful in marital therapy regardless of the religious beliefs of the therapist. Implications for marital therapy are examined.

Adult↗
PubMed1993

Comparison of digestibility, nutritive value, and storage characteristics of different forms of cottonseed in diets fed to lactating dairy cows.

Thirty-two Holstein cows averaging 70 d postpartum were used to compare digestibility of whole short staple cottonseed (SS) to whole Pima (WP), coarsely cracked Pima (CrP), and ground Pima (GP) cottonseeds and their effects on lactational performance. Cottonseed was fed at 15% of diet DM. Milk and solids-corrected milk (SCM) yields were higher for cows fed GP than for cows fed CrP or WP but were not different from yields of cows fed SS. Feed efficiency (SCM/DMI) was higher for cows fed GP and SS than for those fed WP. Milk of cows fed GP was lower in stearic acid but higher in linoleic and linolenic acids than milk of cows fed SS. Whole seeds passing into the feces (percentage of consumed) were higher for WP (12.3%) than for SS (6.2%). Total tract digestibility of ether extract was lower for WP than for other diets. Digestibilities of other nutrients were not different. To test storage characteristics, samples of cottonseed were incubated at 32 degrees C and 30% relative humidity for 0, 10, 20, and 30 d, or stored at ambient temperatures in covered buckets for 9 mo. No differences in amount of free fatty acids between incubated samples were noted, and only CrP stored in buckets for 9 mo was significantly higher in free fatty acids than initial or frozen seed. No differences in aflatoxin were detected, and levels were very low. Milk yield of cows fed GP diets was similar to that of cows fed SS diets and slightly higher than those of cows fed CrP or WP diets. Processing the Pima seed increased feed efficiency.

Animal Feed↗
PubMed1993

Performance of dairy cows fed short staple, Pima, and cracked Pima cottonseed and feed characteristics.

Compared with short staple cottonseed, Pima cottonseed was higher in CP, ether extract, and oleic acid and lower in NDF, ADF, and linoleic acid. Pima cottonseed had greater bulk density, but short staple cottonseed had stronger seed coat strength; Pima cottonseed contained more of the (-)-gossypol isomer than short staple cottonseed. Lactating Holstein cows were fed whole short staple cottonseed, whole Pima cottonseed, and cracked Pima cottonseed at 15% of dietary DM for 70 d after a pretrial covariate period. The DMI was not significantly different among treatments, but cows fed whole Pima tended to yield less milk than those fed short staple and less FCM than those fed cracked Pima. Feed efficiency was improved by processing Pima cottonseed. Milk fat content was higher for whole and cracked Pima than for short staple cottonseed; gross feed efficiency was greatest for cows fed cracked Pima cottonseed. Whole cottonseed in feces was highest for whole Pima, intermediate for short staple, and negligible for cracked Pima cottonseed. Concentrations of milk stearic acid were lower, and linoleic acid higher, for cows fed cracked Pima than for cows fed short staple cottonseed. Total tract digestibility of ADF was least on the cracked Pima cottonseed diet, and ether extract digestibility was higher on cracked than on whole Pima cottonseed diets.

Animal Feed↗
PubMed1990

Beta-adrenoceptors and the effect of beta-agonists on protein metabolism in ovine primary muscle cultures.

The beta-adrenergic receptors of differentiated ovine muscle cultures derived from either fetal or pre-pubertal lambs were characterized by binding of (+/-)-[3H]CGP-12177, directly to intact cells in monolayer. Fetal muscle cells contained a single class of specific and saturable binding sites which had a dissociation constant (Kd) of 0.38 x 10(-9) M and a binding capacity of 55.2 fmol/micrograms protein. beta-Adrenergic agonists competed for the specific binding sites with a typical beta 2-adrenergic specificity. Satellite muscle cells derived from pre-pubertal lambs contained two classes of binding site. The high affinity site had a Kd of 1.02 x 10(-9) M and a binding capacity of 28.4 fmol/micrograms protein and the low affinity site a Kd of 12.1 x 10(-9) M and a binding capacity of 389 fmol/micrograms protein. beta-Adrenergic agonists competed for the specific binding sites with a typical beta 1-adrenergic specificity. The beta-agonist cimaterol had no effect on either protein synthesis or degradation in fetal muscle cells. In cultures derived from satellite cells cimaterol significantly stimulated protein synthesis at concentrations of 10(-8) - 10(-7) M and at 10(-8) - 10(-6) M in the presence of serum. These effects were maintained if 10(-5) M propranolol was added to the incubation media, but were blocked by 10(-6) M isoproterenol. Propranolol and isoproterenol had no stimulatory effects on protein synthesis. Cimaterol also had no detectable effects on protein degradation or the transport of amino acids or glucose. It is concluded that although beta-adrenergic receptors are present in ovine muscle cultures they may not play a role in the anabolic effect of beta-agonists observed in cultured muscle cells.

Adrenergic beta-Agonists↗
PubMed1990

The effects of beta agonists on muscle cells in culture.

Increases in protein synthesis of 12% were found with two myogenic cell lines (L6 and G8-1) on treatment for 6 hr with the beta-adrenergic agonist cimaterol. In L6 cells, propranolol blocked the effect. Protein breakdown measured over 18-24 hr was unchanged. The Kd for cimaterol binding to the L6 beta-receptor was 26 nM which was compatible with its EC50 for the stimulation of protein synthesis (approx 5 nM). Evidence provided with muscle cell lines indicates a direct effect of cimaterol on protein synthesis, which may contribute to muscle accretion in cimaterol-fed animals.

Adrenergic beta-Agonists↗
PubMed1989

Protein metabolism in ovine primary muscle cultures derived from satellite cells--effects of selected peptide hormones and growth factors.

Methods were developed for the isolation and culture of satellite cells from adult sheep muscle. Differentiated cultures of these cells were used to investigate the effects of four hormones and growth factors on protein synthesis and degradation. Insulin was found to have no effect except at supraphysiological concentrations (100 nmol/l and 1 mumol/l) where it is probably crossreacting with the insulin-like growth factor (IGF) type-I receptor. IGF-I was found to be anabolic at lower concentrations (1-3 nmol/l). Epidermal growth factor (EGF) had a smaller effect on protein synthesis and degradation than insulin or IGF-I. The specific activity of the muscle-specific enzyme creatine phosphokinase (CPK) was increased by treatment with EGF. When both IGF-I and EGF were present in the test media an additive effect on protein synthesis was observed. However, no additive effect of IGF-I and insulin was noted. No effects of bovine GH were seen.

Animals↗
PubMed1989

Nutritive value of high moisture alfalfa hay preserved with urea.

Urea (2 and 4%) was added to high moisture hays and compared with untreated wet or dry hays. Means for bale temperatures (degree C) for 1 wk postharvest were highest for wet control (41.2), lowest for dry control (31.4), and intermediate for urea treatments (36.7). By 4 wk postharvest, all temperatures were equal. Protection from molding was most effective for 4% urea, and 2% urea was superior to wet control. By 4 mo postharvest, CP for low urea had decreased due to NH3 loss, and CP for wet control had increased due to DM loss, so they were not different. Initially, ADF was similar for the hays, but after 4 mo storage the wet control was highest (41.7%), the dry control lowest (36.0%), and urea treatments intermediate. Lignin and NDF followed similar trends. In vitro DM digestibilities were highest for the wet control at harvest but lowest at 120 d with high urea and dry control greater than low urea. Feed intakes and milk yields in lactating cows fed the hays were not different. These data show that addition of 2 or 4% urea improved quality of hay baled at about 25% moisture; high urea was more effective than low urea.

Animal Feed↗
PubMed1987

Changes in protein metabolism of ovine primary muscle cultures on treatment with growth hormone, insulin, insulin-like growth factor I or epidermal growth factor.

Methods for the primary culture of muscle cells from fetal sheep were developed which gave high yields of cells. Myoblasts were grown in vitro, and allowed to fuse to form contractile multinucleate myotubes; these could be maintained in a good condition for at least 2 weeks. Protein turnover in these differentiated cultures was examined for sensitivity to each of four potentially anabolic peptide hormones and growth factors: insulin, insulin-like growth factor I (somatomedin C), epidermal growth factor and growth hormone. Insulin was found to have no effect except at high concentrations (1 mumol/l), compatible with its role as a somatomedin analogue. Insulin-like growth factor I was active at lower levels (1 nmol/l) but the cultures were not as responsive to it as were primary rat muscle cultures or differentiated L6 cells, which were tested in similar experiments. The maximum stimulation of protein synthesis observed with the ruminant system was only 16%. Epidermal growth factor was highly anabolic for primary cultures from sheep muscle, and the cells were very sensitive to it, half-maximal stimulation of protein synthesis being seen with concentrations as low as 20 pmol/l. No effects of bovine growth hormone were seen in the ovine system. However, an inhibition of protein breakdown was found with high concentrations (0.1 mumol/l) in the L6 rat myoblast cell line. It was found that the culture conditions used could affect the observed responses of protein synthesis and degradation, despite withdrawal of serum from the incubation media 22 h before testing.

Animals↗