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Biomedical subjects

M E White

Publications and source records attributed to M E White.

At least 55 records · Page 3Linked to original sources
PubMed1998

Effect of a combined trenbolone acetate and estradiol implant on steady-state IGF-I mRNA concentrations in the liver of wethers and the longissimus muscle of steers.

Treatment of lambs (initial BW 28 kg) for 24 d with a combined implant containing 40 mg of trenbolone acetate (TBA) and 8 mg of estradiol (E2) increased ADG 25% (P < .05, n = 8) and feed efficiency 23% (P < .05, n = 2) compared with unimplanted lambs. By d 3 following implantation, sera from wethers implanted with TBA + E2 showed 32% (307 vs 233 ng/mL) increases (P < .001, n = 8) in IGF-I concentration compared with sera from unimplanted wethers. This increase was maintained throughout the entire 24-d study. Steady-state hepatic IGF-I mRNA levels were increased approximately 150% in implanted lambs compared with unimplanted lambs (P < .05, n = 4). These data suggest that liver may be the source of at least part of the increased circulating IGF-I in TBA + E2-implanted sheep. In steers implanted with Revalor-S (120 mg of TBA and 24 mg of E2) for 40 d, the steady-state concentration of IGF-I mRNA in the longissimus muscle was 68% greater than in the longissimus muscle of unimplanted steers (P = .013, n = 4). Consequently, increased local production of IGF-I by muscle tissue may play a role in increasing circulating IGF-I concentrations as well as an autocrine or paracrine role in stimulating muscle growth in steers implanted with Revalor-S.

Anabolic Agents↗
PubMed1997

The relationship of calfhood morbidity with survival after calving in 25 New York Holstein herds.

The association of owner-diagnosed calfhood diseases with the length of herd life after calving was evaluated using data collected prospectively over a ten-year period in 25 New York Holstein dairy herds. Herds selected for the study were milking between 35 and 200 Holstein cows, used dairy herd improvement records, bred cows by artificial insemination unless they needed three or more services, and had regularly-scheduled herd health visits by clinicians from the Cornell University College of Veterinary Medicine. Owners recorded occurrences of dullness, respiratory disease, and scours from birth through 90 days of age for all heifer calves that lived at least 24 h and were to be kept as replacements. Milking herd life was measured as the difference between the age at first calving and the age at death or sale. Data on cows sold when the herd went out of business or still in the herd at the end of the study were censored observations. Cox's proportional hazards model was used for statistical analysis of the data. Controlling for age at first calving, study month of birth, and sire predicted difference for milk, there was no statistically significant association of calfhood morbidity with length of herd life. The estimated hazard rate ratios for leaving the milking herd and 95% confidence intervals for dullness, respiratory disease, and scours within 90 days of birth were 1.3 (0.9, 1.9), 0.9 (0.6, 1.3), and 1.0 (0.8, 1.3), respectively. Dullness was the only disease category with an estimated hazard rate ratio greater than 1, and although it was not statistically significant, may warrant evaluation in future studies of long term effects of calfhood morbidity.

Animals↗
PubMed1997

Risk factors associated with the likelihood of leptospiral seropositivity in horses in the state of New York.

OBJECTIVE: To determine and quantify risk factors associated with exposure of horses to the following serovars of Leptospira interrogans: pomona, autumnalis, and bratislava. ANIMALS: 2,551 horses were randomly selected from a target population during the period of May 1991 to August 1993. PROCEDURES: Blood was collected from the horses and tested for antibodies to serovars, using the microscopic agglutination test. A titer > or = 1:100 indicated seropositivity. Information was collected on each horse, its environment, and each farm's management practices. Logistic regression analysis was used to develop a multidimensional indexing system for indices of exposure and to identify factors significantly-associated with the risk of seropositivity. These indices were: 1) rodent exposure; 2) wildlife exposure; 3) soil and water; and 4) management. RESULTS: Rodent exposure index value was associated with the risk of exposure to all 3 serovars. Management index value was positively associated with the risk of exposure to serovars pomona and bratislava, but not with risk of exposure to serovar autumnalis. Soil and water index value had a positive association with risk of exposure to serovars pomona and autumnalis, but not to serovar bratislava. The wild-life index value and the population density of horses turned out together were associated with the risk of exposure to serovar autumnalis. Age of horse in years was associated nonlinearly (years) and linearly (years) with the risk of exposure to serovars autumnalis and bratislava, and only linearly with the risk of exposure to serovar pomona. CONCLUSION: Risk of seropositivity to the 3 serovars of L interrogans varies according to age, management practices, population density of horses turned out together, and the values of the rodent exposure, wildlife exposure, and soil and water indices.

Agglutination Tests↗
PubMed1996

Molecular cloning and sequence analysis of the porcine insulin-like growth factor binding protein-5 complementary deoxyribonucleic acid.

We report here for the first time the isolation of a cDNA clone containing the open reading frame sequence for porcine insulin-like growth factor binding protein-5 (pIGFBP-5) and the complete deduced amino acid sequence for this porcine IGFBP. The cDNA sequence shares 94%, 90% and 91% identity to its human, mouse and rat counterparts, respectively. The deduced amino acid sequence consists of 252 amino acids and a putative 19 amino acid signal and shares 97%, 96%, and 96% identity to the human, mouse and rat peptides, respectively. The mature peptide contains the 18 conserved cysteines found in all of the IGFBPs. Northern blot analysis of total RNA isolated from porcine heart, muscle and spleen using a 315 base pair cDNA insert derived from the pIGFBP-5 open reading frame sequence revealed a single mRNA transcript of 6.0 kilobases.

Amino Acid Sequence↗
PubMed1996

Porcine reproductive and respiratory syndrome (PRRS): a review, with emphasis on pathological, virological and diagnostic aspects.

Despite early attempts to control the spread of the disease, porcine reproductive and respiratory syndrome (PRRS) has now become endemic in many countries including Britain. The occurrence of subclinical herd infections, the prolonged circulation of virus within herds and probable aerogenic virus spread all mitigated against the success of control measures. The origin of the disease is unknown but the causative agent has been shown to be an arterivirus with shared features to lactate dehydrogenase virus of mice. There is evidence of extreme genetic and antigenic variability between American and European isolates. PRRS virus has a predilection for alveolar macrophages and does not grow in most cell lines. In infected pigs, viraemia can persist for many weeks in the face of circulating antibodies and little is known about the mechanisms by which immunity to infection develops. A wide spectrum of disease has been reported from the field, accompanied in some cases by heavy economic losses. Reproductive and perinatal losses were most prominent when the disease first appeared. In the endemic phase, PRRS may be more significant as a contributory factor to a post-weaning respiratory syndrome of young pigs of 3-8 weeks. On-farm techniques have been developed to reduce the recycling of PRRS virus from older infected nursery pigs to the younger newly weaned pig. Vaccines are now marketed for the control of PRRS, but are not licensed for use in Britain. Improvements in knowledge of virion composition and antigenic stability and in the nature of the immune response of the pig should result in genetically engineered subunit vaccines becoming available. Diagnosis of PRRS is still difficult as many animals do not show clinical signs and may only be detected by serology and often only when other respiratory diseases are being investigated. Now that the infection is widespread, serological testing must be properly targeted and interpreted to give meaningful results about virus circulation. An increasing arsenal of diagnostic methods are becoming available to detect virus in both fresh and fixed specimens. The pathogenic mechanisms of PRRS remain poorly defined and more work is needed to reveal the nature of the interaction between PRRS virus and other factors in disease.

Animals↗
PubMed1996

Expression of insulin-like growth factor II (IGF-II), IGF binding protein-2 and myogenin during differentiation of myogenic satellite cells derived from the turkey.

Myogenic satellite cells are essential for the development of postnatal skeletal muscle. The proliferation and differentiation of these cells are, in part, regulated by the insulin-like growth factors (IGFs), and it has been shown that the IGF binding proteins (IGFBPs) are capable of modulating the actions of IGFs. We have examined the endogenous expression of IGF-II, IGFBP-2 and the myogenic regulatory factor, myogenin, during differentiation of clonally derived turkey muscle satellite cells. Cells were harvested at approximately 80% of confluent density. Additional cultures were rinsed, fed differentiation medium and harvested when approximately 20%, 60% and 80% differentiated (fused). Northern blot analyses were performed using total cellular RNA and labeled rat cDNAs specific for IGF-II, IGFBP-2 and myogenin. A single IGF-II mRNA transcript of approximately 4.0 kb was observed. The relative mRNA abundance was highest in proliferating cultures and decreased with the onset of differentiation, to approximately 60% of initial levels where it remained throughout differentiation. Use of the IGFBP-2 cDNA probe indicated a single mRNA transcript of approximately 2.0 kb. The level of expression of IGFBP-2 mRNA was highest in proliferating cells and decreased to 25%, 16% and 11% of initial levels as differentiation progressed. A single 1.8 kb mRNA transcript was detected with the myogenin probe. Expression of myogenin was undetectable in proliferating cultures and increased significantly as differentiation progressed. Serum-free medium was conditioned for 24 h (CM) at each time point and collected from similar cultures. An IGFBP species of M(r) approximately 30,000 was detected in CM by probing western blots with [125I] IGF-I (ligand blot analysis). The intensity of this band decreased with differentiation to 35%, 24% and 18% of the level for proliferating cultures. Western blots were also probed with an antibody raised against the M(r)-34,000 bovine IGFBP-2. This antibody specifically bound to the M(r)-30,000 IGFBP, and the level of antibody binding decreased as differentiation progressed. It therefore appears that IGF-II, IGFBP-2 and myogenin are expressed in a differentiation-dependent manner by turkey myogenic satellite cells and may thus be involved in the process of differentiation of avian muscle cells.

Animals↗
PubMed1996

Hormonal regulation of IGF-binding protein-2 expression in proliferating C2C12 myoblasts.

No studies have investigated the hormonal regulation of IGF-binding protein-2 (IGFBP-2) secretion and mRNA expression in myoblasts. In this study, cells of the C2C12 mouse myoblast cell line were used to examine the effects of various agents on the hormonal regulation of IGFBP-2. Conditioned medium (CM) was collected and cells were harvested at 2, 4, 6, 15 and 24 h after exposure to treatment media containing porcine insulin (pINS) or recombinant human IGF-I (rhIGF-I), and at 6, 15 and 24 h after exposure to treatment media containing dexamethasone (DEX) or prostaglandin E2 (PGE2). Relative abundance of a single 1.8 kb IGFBP-2 mRNA transcript was determined by Northern analysis using total cellular RNA and a labeled cDNA specific for rat IGFBP-2. IGFBP-2 was detected in CM by probing Western blots with 125I-IGF-I (ligand blot analysis). We have previously shown by immunoblot analysis that the predominant 32,000 M(r) protein on ligand blots is IGFBP-2. Treatment with 10(-9) or 10(-6) M pINS led to a rapid reduction (P < 0.01) in relative IGFBP-2 mRNA abundance and protein secretion relative to controls. Treatment with 7 x 10(-10) or 7 x 10(-9) M (5 or 50 ng/ml) rhIGF-I increased IGFBP-2 mRNA abundance and protein secretion (P < 0.01). Cultures treated with 10(-8) M DEX exhibited significantly increased (P < 0.001) IGFBP-2 mRNA and protein. IGFBP-2 secretion was not affected by 10(-6) M PGE2 but mRNA levels were higher than controls at 24 h (P < 0.01). These findings suggest that multiple factors, including growth factors and metabolic hormones, are involved in regulating IGFBP-2 expression in C2C12 myoblasts.

Animals↗
PubMed1996

Serum insulin-like growth factor I (IGF-I) concentrations are increased in pigs fed antimicrobials.

The effect of antimicrobial supplementation on the sera concentrations of IGF-I was determined in crossbred weanling pigs. Pigs were allotted by weight, litter, and sex to either a control diet or a diet supplemented with ASP-250 (22.7 ppm of chlortetracycline, 22.7 ppm of sulfamethazine, and 11.4 ppm of penicillin) for 5 wk. The diets contained 21.8% crude protein and 1.15% lysine. Growth performance data were collected weekly. Insulin-like growth factor I and insulin-like growth factor binding protein (IGFBP) analyses were performed on blood samples that were drawn during the final week of the trial. Feeding ASP-250 to young pigs increased their sera IGF-I concentrations by 24.8% (P < .001). A 59% increase in sera IGFBP-3 levels also was observed. The pigs fed ASP-250 had a 26% increase in average daily gain (P < .01), a 6.7% improvement in gain:feed ratio (P < .05), and a 18.5% increase in feed consumption (P < .01) compared with pigs fed the control diet. Increased serum IGF-I concentrations with antimicrobial feeding may be involved in the enhanced growth performance observed.

Animal Feed↗
PubMed1996

Effect of concentrate source and amount in diets on plasma hormone concentrations of prepubertal heifers.

Effects of concentrate source (corn or soybean hulls) and amount (40 or 80% of DMI) on plasma hormone concentrations were evaluated for 32 prepubertal Holstein heifers in a 2 x 2 factorial design. Blood samples were collected every other day from d -4 through d 28 of the experiment and were analyzed for growth hormone, prolactin, IGF-1, and glucose. Ruminal samples were collected by esophageal tube on d 0, 7, 14, 21, and 28 and were analyzed for VFA content. Serial blood samples were collected on either d 25 or 26 at 20-min intervals for 8 h and were used for profile analysis of growth hormone and prolactin. Heifers fed 80% concentrate had higher IGF-1 concentrations in serum (158.1 vs. 131.9 ng/ml) than did heifers fed 40% concentrate, and heifers fed corn tended to have higher IGF-1 concentrations than heifers fed soybean hulls. Prolactin concentrations in samples that were collected every other day were higher for heifers fed the 80% soybean hull diet than for those fed 40% concentrate diets or the 80% corn diet. Effects of source and amount of concentrate on plasma prolactin concentrations were not evident in serial samples. Concentrate source or amount had no effect on plasma growth hormone or glucose. At high concentrate intakes, the source (soybean hulls vs. corn) affected intake parameters, ruminal VFA content, and prolactin concentrations.

Acetates↗
PubMed1995

The relationship of the interval from breeding to uterine palpation for pregnancy diagnosis with calving outcomes in holstein cows.

This study used data collected prospectively at 32 dairy herds to examine the effect of interval from breeding to uterine palpation for pregnancy diagnosis on calving interval and likelihood of calving. Multivariable statistical models were used to control for other factors that were significantly associated with the outcomes of interest. Cows diagnosed pregnant from 30 to 36 d post breeding had 2-wk longer calving intervals than cows palpated at later intervals. The interval from breeding until a cow was diagnosed open had a significant positive association with the calving interval. The interval to palpation was not associated with the probability of remaining in the herd to calve when controlling for the effects of herd, season of freshening, number of services, days to first service and mature equivalent milk production. Among cows diagnosed pregnant, 3.4% subsequently were bred and 1.5% were diagnosed open by palpation at a later date. About 5% of the cows diagnosed open calved at a time consistent with being pregnant when the diagnosis was made.

Journal Article↗
PubMed1995

Lectin binding distinguishes between neuroendocrine and neuronal derivatives of the sympathoadrenal neural crest.

Lectin cytochemistry was used to identify surface epitopes selectively expressed by chromaffin cell chemoreceptors (glomus cells) in the rat carotid body. Unexpectedly, these studies revealed that binding sites for peanut agglutinin (PNA; Arachis hypogea) were highly expressed by all neuroendocrine-derivatives of the sympathoadrenal neural crest, including glomus cells, small, intensely fluorescent cells, and adrenal chromaffin cells in situ. In contrast, principal sympathetic neurons did not express PNA receptors. PNA binding was inhibited by 2% galactose. To determine whether expression of PNA receptors was selectively induced by neuroendocrine differentiation of sympathoadrenal precursors, we compared PNA labeling of embryonic sympathoblasts in the presence of either nerve growth factor (NGF) or the synthetic glucocorticoid dexamethasone (DEX). DEX-treated cells, which expressed several neuroendocrine traits, bound PNA, whereas NGF-treated neuronal derivatives did not. In addition, to examine whether expression of existing PNA receptors was down-regulated by neuronal differentiation of chromaffin cells, we compared labeling of PC12 cells, which normally bind PNA, in the presence and absence of NGF. Although PC12 cells acquired characteristic neuronal morphologies in the presence of NGF, they did not lose PNA labeling, even after 8 days of NGF treatment. These findings indicate that neuronal and neuroendocrine derivatives of the sympathoadrenal lineage can be distinguished by differential expression of carbohydrate epitopes and suggest that PNA receptors are induced by neuroendocrine differentiation.

Adrenal Medulla↗
PubMed1995

The onset of maternal diabetes in swine induces alterations in the development of the fetal preadipocyte.

Diabetes induced during gestation has previously been demonstrated to increase adipose accretion in the fetal pig. The present experiment examined whether maternal diabetes alters the proliferation and differentiation of the fetal preadipocyte. Seven crossbred gilts were injected with alloxan (50 mg/kg) at d 75 of gestation to induce diabetes and seven additional gilts were injected with buffer (controls). All gilts underwent Caesarean section of d 105 of gestation. Cells obtained from adipose tissue of fetuses of diabetic swine (FDS) at d 105 of gestation demonstrated a greater (P < .05) proliferative response (57%) and higher (P < .05) rates of differentiation as determined by sn-glycerol-3-phosphate dehydrogenase (142% increase) and lipoprotein lipase (80% increase) activities than cells acquired from fetuses of control swine (FCS). Adipogenic activity of the sera from these two groups of fetuses did not differ when tested on adipose tissue from fetuses at 105 d of gestation. However, use of these sera on cells derived from normal fetuses at 75 d of gestation resulted in detection of an increase (P < .05) in adipogenic activity within the sera from FDS. This study suggests that maternal diabetes causes alterations in the preadipocyte fraction of cells within the developing adipose tissue that result in formation of more adipocytes and thus permits greater capacity for lipid accumulation in the growing fetus of the diabetic pig. These alterations in the preadipocyte result from the activity of factors that transitionally function during the latter half of gestation.

Adipocytes↗
PubMed1995

Lack of association between calf morbidity and subsequent first lactation milk production in 25 New York Holstein herds.

The association of owner-diagnosed calfhood diseases with first lactation milk production was evaluated using data collected prospectively for 728 heifers from 25 New York dairy herds. Cows diagnosed with one or more occurrences of dullness, respiratory disease, or scours within 90 d of birth had first lactation milk production that was similar to that of unaffected herdmates. Estimates for the effects of dullness, respiratory disease, and scours on second test milk production were -1.0, 1.0, and .4 kg/d, respectively (adjusted for season and age at calving, times milked per day, study month on birth, sire PTA for milk production, and the other two calfhood diseases). Estimates for the effects on 305-day mature equivalent production were -139, 123, and 158 kg for dullness, respiratory disease, and scours, respectively (adjusted for study month of birth, sire PTA for milk production, and the other two calfhood diseases). These results were based on data of heifers that were selected as replacements and remained in the herd long enough to have milk production recorded. There was no significant detrimental effect of owner-diagnosed calfhood disease on first lactation milk production, but affected heifers had higher mortality before calving and were less likely to enter the milking herd.

Animals↗
PubMed1994

Heterochronic expression of an adult muscle actin gene during ascidian larval development.

Adultation is a heterochronic mode of development in which adult tissues and organs differentiate precociously during the larval phase. We have investigated the expression of an adult muscle actin gene during adultation in the ascidian Molgula citrina. Ascidians contain multiple muscle actin genes which are expressed in the larva, the adult, or during both phases of the life cycle. In ascidian species with conventional larval development, the larval mesenchyme cells, which are believed to be progenitors of the adult mesoderm, remain undifferentiated and do not express the muscle actin genes. In M. citrina, the mesenchyme cells differentiate precociously during larval development, suggesting a role in adultation. An adult muscle actin gene from M. citrina was obtained by screening a mantle cDNA library with a probe containing the coding region of SpMA1, a Styela plicata adult muscle actin gene. The screen yielded a cDNA clone designated McMA1, which contained virtually the complete coding and 3' noncoding regions of a muscle actin gene. The deduced McMA1 and SpMA1 proteins exhibit 97% identity in amino acid sequence and may be encoded by homologous genes. The McMA1 gene is expressed in juveniles and adults, but not in larval tail muscle cells, suggesting that it is an adult muscle actin gene. In situ hybridization with a 3' non-coding region probe was used to determine whether the McMA1 gene is expressed during adultation in M. citrina. McMA1 mRNA was first detected exclusively in the mesenchyme cells during the late tailbud stage and continued to accumulate in these cells during their migration into the future body cavity and heart primordium in the hatched larva. The McMA1 transcripts persisted in mesenchyme cells after larval metamorphosis. It is concluded that an adult muscle actin gene shows a heterochronic shift of expression into the larval phase during adultation in M. citrina.

Actins↗
PubMed1994

Developmental changes in serum IGF-1 and IGFBP levels and liver IGFBP-3 mRNA expression in intrauterine growth-retarded and control swine.

The 29 M(r) x 10(-3) IGFBP was significantly elevated (P < 0.01) in IUGR piglets at 90 days fetally and at birth. Developmentally, 29 M(r) x 10(-3) IGFBP levels were higher fetally and at birth than at 21 and 49 days of age (P < 0.05). At 90 days fetally, hepatic IGFBP-3 mRNA levels were very high, while circulating levels of IGFBP-3 were extremely low whereas postnatally, hepatic IGFBP-3 mRNA and serum IGFBP-3 levels were parallel. This study provides new information concerning the developmental expression of IGFBP-3 and the relationship between serum levels of the 29 M(r) x 10(-3) IGFBP and IUGR in swine.

Animals↗
PubMed1994

Cholera in metropolitan Manila: foodborne transmission via street vendors.

Reported are the results of an unmatched case-control study to determine the risk factors associated with acquisition of cholera in Manila. Cases were patients admitted to the San Lazaro Hospital between July and September 1989 and whose stools yielded Vibrio cholerae O1 on culture. Controls were patients admitted to the same hospital and who had no history of diarrhoea or of having taken antibiotics during the 3 days prior to admission. Of the 158 cases and 158 controls who had bought food from street vendors, cases were more likely to have bought the following items: pansit (rice noodles with shrimp, meat, and vegetables), mussel soup, spaghetti, fish balls, pig blood coagulated with vinegar, and salty brine shrimp with vegetables. Cases were also more likely to lack piped water at home. An unconditional logistic regression analysis indicated that only pansit (OR = 2.15, 95% CI = 1.32-3.51), mussel soup (OR = 2.29, 95% CI = 1.06-4.95), and the absence of piped water at home (OR = 2.70, 95% CI = 1.63-4.46) remained as risk factors. As control measures we recommend stricter implementation of the food sanitation code and the licensing of street food vendors.

Adolescent↗