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Biomedical subjects

R H Ingraham

Publications and source records attributed to R H Ingraham.

35 records · Page 2Linked to original sources
PubMed1986

Calmodulin and troponin C: a comparative study of the interaction of mastoparan and troponin I inhibitory peptide [104-115].

Recent studies using bee and wasp venom peptides have led to the hypothesis that proper complex formation with calmodulin (CaM) requires the presence of a basic amphiphilic helix on the surface of the target protein [Cox, J. A. (1984) Fed. Proc., Fed. Am. Soc. Exp. Biol. 43, 3000]. We have tested this hypothesis by examining CaM and troponin C (TnC) complex formation with two basic peptides, the wasp venom tetradecapeptide mastoparan and the physiologically relevant synthetic troponin I (TnI) inhibitory peptide [104-115], using far-ultraviolet circular dichroism as a secondary structure probe. Complex formation between mastoparan and either CaM or TnC results in an increase in helical content, whereas the helical content of TnI inhibitory peptide does not increase when bound to either protein. Significantly, mastoparan is 78% alpha-helical in a 50% solution of the helix-inducing solvent trifluoroethanol and has a high helix-forming potential according to the Chou-Fasman rules while TnI inhibitory peptide contains none and is not predicted to have any. We interpret these data as indicating that these peptides exhibit substantially different secondary structures upon binding to CaM or TnC. The ability of mastoparan to regulate the acto-subfragment 1-tropomyosin ATPase has also been examined. Mastoparan and TnI inhibitory peptide inhibited 31% and 45% of the activity, respectively. TnC and CaM promote differing degrees of Ca2+-sensitive release of inhibition by both peptides. Sequence comparison suggests that the basic residues present in both peptides are important for binding. However, we conclude that an alpha-helical structure is not a prerequisite for the binding of target proteins to CaM and TnC.

Actins↗
PubMed1986

Observations on the use of prostaglandin F(2alpha) as an abortifacient and effect of gonadotrophin-releasing hormone on ovarian activity after induced abortion during the breeding season in goats.

Results of two experiments are described. In the first experiment, forty-one mixed-breed goats (does) with unknown gestation lengths were given 10 mg prostaglandin F(2alpha) (PGF(2alpha)) (2 doses of 5 mg each, 24 h apart) i.m. Blood samples were obtained before each treatment with PGF(2alpha) by jugular venipuncture, and plasma progesterone (P(4)) concentrations were determined by a nonextraction solid-phase radioimmunoassay. P(4) concentrations (ng/ml) were significantly decreased (15.47 vs 1.55, P<0.005) 24 h after the first injection of PGF(2alpha). A total of 63 fetuses was collected within 46.5 h following the first injection. Mean (+/- SE) crownrump lengths and body weights of 62 fetuses were 21.46 +/- 0.29 centimeters (cm) and 575.00 +/- 20.60 g, respectively. Based on these findings, the mean gestation length of these does was estimated to be 86.96 +/- 0.74 d. Thirty-one does retained their placenta for 12 to 72 h and were treated with a single injection of 5 mg PGF(2alpha) and 800 mg oxytetracycline i.m. Placental expulsion in all does occurred within 24 h posttreatment. The results of this study suggest that two doses of 5 mg PGF(2alpha) intramuscularly (i.m.) 24 h apart is an effective abortifacient at about 3 mo of pregnancy in does. In the second experiment, 38 does from the first experiment were divided in two groups of 19 each on Day 13 postabortion. Group A (treated) was given 50 ug GnRH i.m. while Group B (control) received 1 ml 0.9% saline i.m. Blood samples were obtained prior to treatment and on Day 23 postabortion and assayed for P(4) concentrations. There was no significant difference (P>0.10) in P(4) concentrations of samples obtained pre- and post-GnRH treatment. However, 14 of 19 and 12 of 19 in Groups A and B, respectively, exhibited estrus within 52 days following abortion. Twenty-six does were bred naturally and 17 became pregnant.

Journal Article↗
PubMed1986

Effect of serum sources and colostral whey on bovine semen quality and spermatozoa immunoglobulin G immunofluorescence.

Heifer, bull, fetal calf sera, and colostral whey were used to evaluate the influence of protein concentrations on percent progressive motility, head-to-head agglutination, acrosomal integrity, and immunoglobulin G immunofluorescence of bovine spermatozoa using ejaculates from 10 bulls. In the first experiment, 10% (vol/vol) addition of undiluted colostral whey resulted in the highest head-to-head agglutination, acrosomal integrity, and immunoglobulin G immunofluorescence. Ten percent (vol/vol) addition of whey diluted to a protein concentration equivalent to fetal calf serum produced significantly lower agglutination, acrosomal integrity, and immunoglobulin G immunofluorescence. Fetal calf serum was unable to produce agglutination and immunoglobulin G immunofluorescence of bovine spermatozoa. Heifer and bull sera produced similar responses for all seminal measurements. In Experiment 2, unheated whey and heifer serum resulted in higher response for all variables than heat inactivated whey and heifer serum. Whey treatment produced greater spermatozoal motility, agglutination, acrosomal integrity; and immunoglobulin G immunofluorescence than treatment with heifer serum. Spermatozoal immunofluorescence indicated antibodies in normal whey, bull, and heifer serum bound to spermatozoal membranes at the acrosomal region. Colostral whey was an effective source of agglutinin factor. Normal unheated whey and heifer serum did not cause sperm damage or immobilization.

Animals↗
PubMed1985

Interaction of troponin and tropomyosin: spectroscopic and calorimetric studies.

The thermodynamic parameters characterizing the interaction between rabbit fast skeletal muscle troponin and tropomyosin have been determined at 25 degrees C for three solution conditions: buffer containing (A) 1 mM CaCl2, simulating a "turned-on" state, (B) 3 mM MgCl2, simulating a "turned-off" state, and (C) 2 mM ethylenediaminetetraacetic acid, a reference state. The enthalpies were measured in two buffers with different heats of ionization to allow correction for dissociation or uptake of protons. The enthalpies corrected for proton effects are -22.1, -25.4, and -23.5 kcal/mol, respectively, in buffers A, B, and C. The interaction between troponin and tropomyosin in the presence of calcium is accompanied by release of 0.9 mol of proton per mole of complex. Proton effects in the presence of magnesium and in the absence of divalent metal ions were too small to quantitate. The association constants were measured by using tropomyosin labeled with the extrinsic fluorescent probe dansylaziridine, and binding was detected by enhancement of the probe fluorescence. The magnitudes of the association constants for unlabeled troponin are 7.5 X 10(5), 4.2 X 10(5), and 9.5 X 10(5) M-1, respectively, for the three solution conditions corresponding to unitary free energies of -10.4, -10.1, and -10.6 kcal/mol. The unitary entropies for the interaction are -39, -51, and -43 cal/(deg X mol), respectively, for the three solution conditions. Under these conditions, the troponin-tropomyosin interaction is enthalpy driven, and a large unfavorable entropy must be overcome in the formation of the complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effect of phenylbutazone (PBZ) on luteolysis in the mare induced by uterine biopsy.

Uterine biopsy in the mare on day 4 post-ovulation causes an acute inflammatory reaction which results in premature luteolysis. In this study, seven mares (4 to 6 years of age) were used in a switchback experimental design to test the hypothesis that in the mare parenterally administered PBZ will block luteolysis induced by uterine biopsy on day 4 post-ovulation. All mares were allowed two normal estrous cycles (range 18 to 24 days). On the first day of estrus of the third estrous cycle each mare was intravenously given 2 grams PBZ (treatment) or 10 ml 0.9% saline (control) daily until signs of estrus were exhibited. The day of ovulation (day 0) was determined by rectal palpation and subsequently verified by peripheral plasma progesterone concentrations. On day 4 following ovulation all mares were subjected to uterine biopsy, and subsequent estrus detection was performed daily using an andro-genized gelding. A total of 19 estrous cycles (ten for PBZ treatment and nine for controls) were evaluated. Mean number of days (+/-SE) from uterine biopsy to induced estrus was 5.00+/-0.16 for control cycles and was significantly different (P<0.025) when compared with 9.20+/-0.34 days for treatment cycles. Results of this study suggest that PBZ can block luteolysis in the mare induced by uterine biopsy on day 4 post-ovulation, possibly as a result of accumulating PBZ in acutely inflamed uterine tissue and inhibiting prostaglandin synthesis.

Journal Article↗
PubMed1984

Binary interactions of troponin subunits.

The association constants for the formation of the binary complexes of rabbit fast skeletal muscle troponin subunits have been determined for three solution conditions: (a) 1 mM CaCl2, (b) 3 mM MgCl2 and 1 mM EGTA, and (c) 2 mM EDTA. The subunits were labeled with extrinsic fluorescence probes, either 5-(iodoacetamido)eosin (IAE) or dansylaziridine (DANZ), and the binding was detected by enhancement or quenching of the probe fluorescence. The association constant for the TnI X TnT (where TnI and TnT are the inhibitory subunit and the tropomyosin-binding subunit, respectively, of troponin) complex was measured with two different probes, IAE-TnI and IAE-TnT. The measured values were not affected by the presence of Ca2+ or Mg2+, and the mean values for the three buffer conditions are, respectively, 8.0 X 10(6) and 9.0 X 10(6) M-1 for the two probes. The association constant for TnC-TnI (where TnC is the Ca2+-binding subunit of troponin) interaction was measured with three probes, IAE-TnC, DANZ-TnC, and IAE-TnI. Values of 1.7 X 10(9), 1.2 X 10(8), and 1.0 X 10(6) M-1 were obtained, respectively, in the presence of calcium ion, in the presence of magnesium ion (no calcium), and in the absence of divalent metal ions. A mean value of 4.0 X 10(7) M-1 was obtained for the association constant of TnC X TnT using DANZ-TnC and IAE-TnC as probes in the presence of calcium or magnesium ions. A value of 4.5 X 10(6) M-1 was obtained in the absence of divalent metal ions. The results show that the presence of magnesium ion in the Ca2+-Mg2+ sites strengthens the TnC-TnI and the TnC-TnT interactions and suggest that the troponin structure would be stabilized. This likely results from the effect of magnesium ion on the Ca2+-Mg2+ domains of TnC. The presence of calcium ion in the Ca2+-specific sites provides an additional binding free energy for the TnC-TnI interaction which presumably reflects the changes in the subunit interactions required for the calcium regulatory switch.

Animals↗
PubMed1984

Inability of progestogen pretreatment to prevent premature luteolysis of induced corpora lutea in the anestrous bitch.

Fourteen mature anestrous bitches were used to determine the effectiveness of pretreatment with an orally active progestogen to prevent premature luteolysis of induced corpora lutea (CL) in the anestrous bitch. In Group 1, seven bitches were treated orally with megestrol acetate (Ovaban((R))) at the rate of 2.2 mg/kg body weight for eight days. Three days later, the bitches were treated daily with pregnant mare's serum gonadotropin (PMSG) (44 IU/kg body weight) administered intramuscularly for nine consecutive days, and each bitch was given 500 IU human chorionic gonadotropin (HCG) on day 10, or on the first day of induced estrus if the bitches exhibited estrus while being treated with PMSG. A control group (Group 2) of seven bitches was not treated with Ovaban((R)) but was similarly given PMSG and HCG. Estrus was detected twice daily using a vasectomized male dog and verified by vaginal cytology. Blood samples were obtained on the first day of induced estrus (day 0) and every other day until day 90 post-estrus. Plasma progesterone (P(4)) concentrations were determined by a non-extraction solid phase radioimmunoassay (RIA), and data were analyzed by Student's t-test. There was no significant difference between the progesterone profiles of both groups of bitches. In addition, P(4) values were less than 1 ng/ml by day 50 post-estrus. Results of this study suggested that pretreatment with an orally active progestogen was not effective in preventing premature luteolysis of induced CL in the anestrous bitch.

Journal Article↗
PubMed1984

Relationship between fertility and blood glucose and cholesterol concentrations in Holstein cows.

Jugular blood samples were collected prepartum and postpartum from 97 Holstein cows and heifers. Samples were analyzed for total serum cholesterol and plasma glucose. Plasma samples taken 4, 11, 18, and 25 days postpartum were also analyzed for progesterone. Concentrations of cholesterol, glucose, and progesterone were evaluated in relation to summer- and winter-calving seasons, milk production, lactation number, days-to-conception, number of postcalving uterine infusions given, and time relative to calving. A temperature-humidity index was used as a covariate in the analysis to adjust the data for climatic effects so that seasonal effects other than temperature and humidity could be determined. Average plasma glucose was within the normal range (62 +/- 8 mg/dl). It increased before calving and then declined to a minimum value between 11 and 25 days postpartum. Glucose then increased after 25 days for the summer-calving group and remained relatively stable for the winter-calving cows. Blood glucose concentrations were inversely related to milk production. Negative correlations existed between milk production and plasma glucose at days 4, 11, 18, 25, and 39 postpartum. First-lactation heifers had higher blood glucose levels than cows in their second or later lactation. Blood glucose concentrations were not related to days-to-conception over both seasons. Average serum cholesterol was within the normal range (125 +/- 29 mg/dl). It decreased before calving and then increased for 88 days after calving. Summer-calving cows had higher serum cholesterol concentrations prepartum and winter-calving cows had higher concentrations from 39 through 88 days postpartum. Cholesterol concentrations were directly related to milk production from 25 through 88 days postpartum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Plasma copper concentration and packed cell volume and their relationships to fertility and milk production in Holstein cows.

Jugular blood samples were obtained from 55 summer-calving and 40 winter-calving Holstein cows fed diets which averaged 7.4 micrograms of Cu/g. Samples were collected within 3 days of 30, 11, and 4 days before calving and 4, 11, 18, 25, 39, 60, 88, 116, and 147 days after calving. Packed cell volume and plasma Cu concentrations were determined. Blood components were analyzed in relationship to season, milk production, lactation number, number of days to conception, number of postcalving uterine infusions, and time relative to calving. The environmental temperature-humidity index was used as a covariate in the analysis, so that seasonal effects represented feeding or production differences between seasons and were not due to the direct effects of climate. Plasma Cu concentrations were within the usual laboratory limits (1.05 +/- 0.20 microgram/ml). These values were unrelated to PCV in the summer-calving cows, but were slightly related in the winter-calving cows (r = 0.11). Plasma Cu values increased around the time of calving, with the maximum level (1.13 microgram/ml) occurring on postpartum day 11. Plasma Cu concentration was higher in cows that conceived within 80 days of calving than in cows which conceived at 120 days or more. Differences in plasma Cu among fertility groups were most evident during postpartum days 25 to 60. However, the relationship between plasma Cu concentrations and fertility was not consistent. Significant interactions existed for season X fertility groups and milk production groups X fertility groups. Plasma Cu concentration was significantly higher for the summer-calving cows and was inversely related to milk production level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Selenium concentrations in feeds and effects of treating pregnant Holstein cows with selenium and vitamin E on blood selenium values and reproductive performance.

Holstein cows (n = 104) and heifers (n = 35) were used to determine the effects of treatment with selenium (Se) and vitamin E on whole blood Se values and fertility. At 21 +/- 3 days before parturition, 55 cows and 19 heifers were injected with 680 IU of vitamin E and 50 mg of Se as sodium selenite. Treatment had no effect on days to first estrus, days to first service, days to conception, services per conception, or number of uterine infusions required. Blood samples were obtained from 33 nontreated cows and heifers and 32 treated animals at 21 and 14 days (+/- 3) before calving and at 7 and 14 days (+/- 3) after calving. Mean whole blood Se level at -21 days (day 0 was day of parturition) and before Se-vitamin E treatment was 0.109 micrograms/ml. At days -14, 7, and 14, blood Se was significantly higher in the treated than the non-treated animals. Blood Se was lower on all sampling days in cows calving in July through November than in cows calving in December through April. Heifers in their 1st lactation had lower blood Se concentrations than did cows in their 2nd or later lactation. In feeds sampled at 2-week intervals, mean concentrations of Se in Bahia grass, mixed ryegrass and oats, corn silage, and sorghum silage were less than 0.1 micrograms/g on a dry matter basis. Bermuda grass, alfalfa hay, and concentrates contained greater than 0.1 micrograms of Se/g. Large variation existed in Se concentrations of individual feedstuffs.

Animal Feed↗
PubMed1983

Stability of the Ca2+-specific and Ca2+-Mg2+ domains of troponin C. Effect of pH.

The unfolding of rabbit fast skeletal muscle troponin C has been examined as a function of pH using differential scanning calorimetry as a probe. Studies were conducted between pH 7.2 and 5.25 in the absence of both Ca2+ and Mg2+. At pH 7.2, a single unfolding transition, with a tm of 58 degrees C, is observed. Decreasing the pH to 5.5 increases the tm for this transition to 67 degrees C. At pH values less than or equal to 5.5, a second unfolding transition is observed, which has a tm of 51 degrees C. These studies suggest that troponin C consists of two types of structural domains: one has a compact structure throughout the pH range examined; the other has a poorly ordered structure at pH 7.2 which becomes more compact as the pH is decreased. We conclude that stabilization of both types of domains occurs through protonation of carboxylate groups clustered in each of the four Ca2+-binding loops. Our data are consistent with assignment of the higher-temperature transition to unfolding of the N-terminal portion of the molecule, which contains the Ca2+-specific domains and of the lower-temperature transition to unfolding of the C-terminal portion, which contains the Ca2+-Mg2+ domains.

Animals↗
PubMed1983

The effect of exogenous acth and pen-confinement on estrous cycle length, plasma steroid levels and ovarian function of beef heifers.

Each of 24 pasture-reared crossbred beef heifers were herded from a large pasture on day 14 of the estrous cycle and assigned randomly to one of four treatment groups as follows: Field Control (FC), Field ACTH (FA), Pen Control (PC) and Pen ACTH (PA). Field groups were maintained in a small field, and pen groups were confined in a pen in a pole barn. ACTH groups received 200 IU of ACTH IM daily for days 17 through 21 of the cycle and control groups received only the gelatin carrier IM on the same cycle days. Average cycle lengths for FA and PA heifers were 25 and 24.3 days with an average period from plasma progesterone decline below 1 ng/ml to estrus of 5.5 days. During the ACTH injection period, follicular growth was suppressed and the proestrus plasma estrogen rise was delayed. Average cycle lengths for FC and PC heifers were 20.8 and 22.8 days respectively. All control group heifers exhibited estrus within 2 days of the plasma progesterone decline below 1 ng/ml. In addition, pen confinement heifers showed a trend for extended luteal function and consequent extended estrous cycle length.

Journal Article↗
PubMed1979

Seasonal effects of tropical climate on shaded and nonshaded cows as measured by rectal temperature, adrenal cortex hormones, thyroid hormone, and milk production.

Rectal temperatures and hormone concentrations were monitored at intervals of 2 to 3 weeks, and milk, milk fat, and California mastitis test scores at intervals of 1 week in five shaded and in four nonshaded early lactation cows. Measurements were taken from September to December in the mildly heat stressing climate of Oahu, Hawaii. The daily ambient temperature flux ranged from 22 C to 29 C in September to 20 C to 25 C in December. Average daily temperature-humidity index (THI) values were 75 to 70 for September and December, respectively. Average daily THI values were correlated with rectal temperatures in nonshaded cows and were negatively correlated with plasma adrenal cortex hormones (corticoids) in shaded cows, plasma thyroid hormone in shaded and nonshaded cows, and with milk production in nonshaded cows. Estimated milk production decline per unit increase in THI was 0.32 kg. Nonshaded cows had higher rectal temperatures, a trend for lower plasma corticoids, produced less milk and milk fat, and had higher California mastitis test scores. Shaded cows maintained a higher fat percentage at THI above 74. Average plasma thyroid hormone values were not different between treatment groups. Both groups failed to attain normal rectal temperatures at night. Afternoon rectal temperatures were more highly correlated with the rectal temperature with which the cow started the day than they were with the THI of the day itself.

Adrenal Cortex Hormones↗
PubMed1976

Relationship of temperature and humidity to conception rate of Holstein cows in Hawaii.

Weather data and breeding records for a Holstein herd of 1300 cows in Hawaii were evaluated to determine effects of climate on reproductive performance. The dairy is in a coastal climate near latitude 21 degrees N. Average maximum temperature, relative humidity, and resulting temperature-humidity index for the warmest month of the year were 31 C, 44%, and 79. Average minimum temperature and attending values for the same period were 20 C, 96%, and 68. From late April to November, conception rates were correlated negatively with the average temperature-humidity index of each day of the estrous cycle beginning 11 days prior to breeding. Slopes of regression lines differed, suggesting varying sensitivity of conception rate to heat stress on different days of the cycle. The temperature-humidity index of the 2nd day prior to breeding was most closely correlated with conception rate. Conception rates declined from 66% to 35% as the index increased from 68 to 78. Only the temperature-humdity index of the 2nd day prior to breeding had a significant partial correlation coefficient when the index of the 2nd and 1st day prior to breeding, the day of breeding, and the day following breeding were each evaluated with the index of the others held constant.

Animals↗