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Biomedical subjects

R Adair

Publications and source records attributed to R Adair.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effect of melengestrol acetate (MGA) or progesterone-releasing intravaginal device (PRID) on follicular development, concentrations of estradiol-17 beta and progesterone, and luteinizing hormone release during an artificially lengthened bovine estrous cycle.

Two trials were conducted to determine whether 7-d progestogen treatment beginning on d 17 of the estrous cycle altered 1) ovarian follicular development, 2) serum concentration of estradiol-17 beta (E2) and progesterone (P4), and 3) patterns of release of luteinizing hormone (LH). In both trials, Angus, Angus x Holstein, or Holstein cows 2 to 6 yr of age were randomly assigned to receive either melengestrol acetate (MGA, .5 mg.animal-1.d-1; n = 23), a progesterone-releaseing intravaginal device (PRID, n = 26) or to serve as untreated Controls (n = 14). Ultrasonography and blood sampling were performed daily throughout the experiment beginning on d 3 (Trial 1) or d 9 (Trial 2) of the estrous cycle. In Trial 2, blood samples were collected every 15-min for 6 h on d 17 (all cows) and d 20 and 23 (MGA and PRID cows) for determination of LH. Estrous cycle length was 3 to 5 d greater (P < .05) for MGA- and PRID-treated cows characterized by two (MGA-2 and PRID-2) or three (MGA-3 and PRID-3) dominant follicles than for control cows exhibiting two (Control-2) or three (Control-3) dominant follicles. A greater proportion (P < .05) of MGA- than of PRID-treated cows ovulated the follicle that was dominant at the beginning of treatment on d 17 (10 of 23 vs 1 of 26). Serum P4 concentrations declined 3 d earlier in Control-2 and MGA-2 cows than in Control-3, MGA-3 or PRID-3 cows.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravaginal↗
PubMed1993

The time required for the presence of bulls to alter the interval from parturition to resumption of ovarian activity and reproductive performance in first-calf suckled beef cows.

This experiment was designed to determine 1) if exposure of firstcalf suckled beef cows to mature bulls in the first 30 days, after 30 days, or continuously post partum reduces the postpartum anestrous period and 2) if exposure to bulls alters the first service pregnancy rate. Postpartum first-calf suckled crossbred (Angus x Hereford; Hereford x Angus) cows were randomly assigned to be 1) exposed continuously to mature, epididectomized bulls (BE; n = 18); 2) exposed to bulls for the first 30 days post partum (BE/NE; n = 17); 3) exposed to bulls after the first 30 days post partum (NE/BE; n = 16); or not exposed to bulls (NE; n = 18). Blood samples were collected weekly to be assayed for progesterone to determine resumption of ovarian cyclic activity. All the cows were bred for 21 days by AI while under their respective treatment regimens and were then exposed to fertile bulls for an additional 35 days. The postpartum interval to resumption of ovarian cyclic activity did not differ (P>0.10) among the 3 (BE, BE/NE, and NE/BE) treatment groups, but it was 15.4 d shorter (P<0.05) than for cows in the NE group. The overall pregnancy rates did not differ (P>0.10) among the treatment groups. The AI pregnancy rates for the BE/NE and NE/BE treatment groups were higher (P<0.05) than for the NE group. The AI pregnancy rates for the BE and NE treatment groups did not differ (P>0.10). The results showed that all three treatments (BE, BE/NE and NE/BE) similarly decrease the postpartum interval and that exposure to bulls may improve the reproductive performance of first-calf suckled beef cows.

Journal Article↗
PubMed1992

Cortisol and prolactin concentrations during three different seasons in relocated Brahman and Hereford bulls.

The objective of this study was to evaluate seasonal changes of cortisol and prolactin (PRL) concentrations in Brahman and Hereford bulls moved to locations that differ in geographical and environmental conditions. Postpubertal Hereford bulls from Montana (n = 15) and Nebraska (n = 15) and Brahman bulls from Texas (n = 18) were located in or relocated to Montana, Nebraska or Texas so that each location had 5 Montana Herefords, 5 Nebraska Herefords and 6 Texas Brahman bulls. Blood samples were collected at 20-minute intervals for 8 hours in November (Fall 1), April (Spring) and November (Fall 2) of the next year. These dates corresponded to 6, 12 and 18 months, respectively, after relocation in May of the first year. Cortisol concentrations were higher (P<0.05) in Fall 1 than in Fall 2 and were higher (P<0.05) for bulls in Montana than for bulls in Texas. The decrease in cortisol concentrations from Fall 1 to Fall 2 was negatively related (P<0.05) to age and weight. There was a three-way interaction (P<0.05) of breed-type origin, location and season for PRL concentrations. Seasonal patterns of PRL concentrations differed between relocated Texas Brahman and Hereford bulls, and patterns for relocated bulls differed from those of the nonrelocated bulls. Seasonal patterns of PRL were influenced to a greater extent by relocation in Texas Brahman bulls than in Hereford bulls.

Journal Article↗
PubMed1992

Reducing night waking in infancy: a primary care intervention.

Approximately 25% of infants wake regularly at night and need help in resettling. The purpose of this study was to implement and evaluate a brief intervention to prevent such night waking. The study used a prospective cohort design with historical controls. Information from the control group was collected at the 9-month visit. The intervention group was enrolled at the 4-month visit. The intervention consisted of information about sleep-onset associations, completion of a sleep chart, and discussion about sleep with the pediatrician. The outcome was also measured at the 9-month visit. To obscure the purpose of the study, the outcome questionnaire for both groups addressed feeding and sleeping. One hundred twenty-eight (74%) of 172 eligible infant-parent pairs comprised the control group and 164 (74%) of 222 the intervention group. The majority of families were white, married, and well-educated. The groups were similar with regard to sociodemographic variables and factors thought to be related to night waking such as current breast-feeding, thumb/pacifier sucking, maternal isolation, and parental perception of difficult child. At 9 months of age, the intervention infants were reported to experience 36% less night waking per week compared with those in the control group (2.5 vs 3.9 wakings per week, P = .02). Frequent night waking was twice as common in control infants (27% vs 14%, P = .01). It is concluded that this pediatric intervention can help parents reduce night waking in infants.

Cohort Studies↗
PubMed1991

Night waking during infancy: role of parental presence at bedtime.

Night waking occurs commonly in infants and young children. The goal of this study is to determine whether parents who report being present when their infant falls asleep at bedtime are more likely to report increased frequency of night waking by the infant. Mothers were consecutively recruited when they brought their infants to the clinic for their 9-month well-child visit. A total of 122 mothers agreed to participate and completed a questionnaire consisting of closed-ended, forced choice questions about their infant's feeding and sleeping behavior, and demographic and psychosocial characteristics. For 33% of the mothers, a parent was routinely present when the infant went to sleep. The entire sample of infants averaged 4.1 night wakings during the week prior to questionnaire completion. Infants whose parents were present at bedtime were significantly more likely to wake at night than infants whose parents were not present (6.2 vs 3.1, P = .01). Frequent night waking (seven or more wakings in the prior week) occurred in 28% of the sample. More of the infants whose parents were present experienced frequent night waking compared with infants whose parents were not present (40% vs 22%, P less than .04). When potential confounding variables were controlled by multivariate analysis, parents being present when the child went to sleep was independently associated with night waking (P less than .03). The association of parental presence at bedtime and night waking has implications for preventing and managing disruptive night waking in infancy.

Behavior↗
PubMed1990

Postpartum interval to estrus and patterns of LH and progesterone in first-calf suckled beef cows exposed to mature bulls.

Two trials were conducted in which Angus x Hereford first-calf cows were assigned randomly at calving to one of two treatments: exposure to mature penile-blocked bulls (BE) or isolation from bulls (NE). In Trial 1 (BE, n = 38; NE, n = 37), cow to bull ratio increased from 12:1 to 19:1 over a 14-d period; in Trial 2 (BE, n = 25; NE, n = 24), this ratio was maintained at 13:1. In both trials, blood samples were collected weekly for progesterone and ovaries and uteri of cows were examined rectally. Cows were observed for estrus twice daily (am:pm) beginning 10 d after calving. In Trial 2, intensive blood sampling for LH began 10 d after calving (eight cows per treatment) and continued at weekly intervals until estrus or the end of the trial. Postpartum weight change, condition score change and time to uterine involution did not differ (P greater than .10) between treatments in either trial. Interval to estrus was shorter (P less than .05) for BE cows than for NE cows in both trials. A greater proportion (P less than .05) of BE cows exhibited estrus by 60 and 90 d after calving and showed an increase in progesterone before first estrus. Mean and baseline LH concentrations and amplitude, frequency and duration of LH pulses were not altered (P greater than .10) by bull exposure. In conclusion, exposing first-calf suckled beef cows to bulls after calving hastened resumption of estrous cycles. Bull exposure did not alter patterns of LH concentrations but did increase proportions of cows that showed increased progesterone before first estrus.

Animals↗
PubMed1989

Effect of prostaglandin F2alpha dosage and stage of estrous cycle on the estrous response and corpus luteum function in beef heifers.

Ninety-five normal cyclic crossbred beef heifers were used to determine if the proportions of heifers showing estrus, intervals to estrus and corpus luteum (CL) function were influenced by PGF2alpha dosage and (or) the stage of luteal phase when PGF2alpha was administered. Heifers were assigned randomly to treatments in a 4x3 factorial arrangement. Treatments were 5, 10, 25 or 30 mg PGF2alpha injected either in early (5 to 9 d), mid (10 to 14 d) or late (15 to 19 d) stages of the luteal phase. Jugular samples were taken at 0 h and at 8 h-intervals for 48 h and again at 60 h after PGF2alpha treatment for progesterone assay. Heifers were observed for estrus continuously for 120 h PGF2alpha treatment. The proportion of heifers showing estrus was dependent upon (P<0.05) both dosage of PGF2alpha and stage of luteal phase. Heifers given 5 mg of PGF2alpha showed estrus only if treated during the late stage, while those given 10 mg of PGF2alpha showed a progressive increase of heifers in estrus as stage of luteal phase advanced. The proportion of heifers showing estrus after 25 and 30 mg of PGF2alpha increased from 56% for the early stage to 100% for the mid and late stages. Interval to estrus in heifers showing estrus within 120 h after PGF2alpha treatment did not differ (P>0.05) among dosages but tended (P=0.10) to be longer in heifers treated during the mid luteal stage (67 h) than in heifers treated in the two other stages (56 h). A greater proportion of heifers (P<0.05) showed estrus by 60 h after PGF2alpha when treated during the early and late luteal stages (75.5%) than for heifers treated during the mid luteal stage (30.4%). Patterns of progesterone concentrations were influenced (P=0.08) by the three way interaction of dosage, stage and time. In heifers that showed estrus, rate of decline in progesterone tended (P=0.07) to be slower during the mid luteal stage than during the early and late stages. Progesterone did not drop below 1 ng/ml until 32 h in heifers treated during the mid luteal stage; whereas progesterone dropped below 1 ng/ml by 24 h in heifers treated during the early and late stages. These data may be useful in designing more efficient systems for using PGF2alpha or its analogues in estrus synchronization of beef cattle.

Journal Article↗
PubMed1988

Divorce and children.

The divorce rate in the United States is currently half the rate of marriages. Whether this rate will continue is not known. Millions of American children have already experienced their parents' divorce and millions more are likely to share the experience in the future. This makes divorce a problem that frequently appears in a pediatrician's patient population. Most children of divorce will experience it at the least as a potent transient stress that disrupts virtually all aspects of their lives. Many will accommodate to their new life circumstances successfully, but a substantial percentage will suffer long-term negative effects. Many of the problems of these children and their families can be anticipated, prevented, or alleviated by thoughtful and timely intervention. The pediatrician can be helpful by serving as the child's advocate, offering anticipatory guidance, helping the family weather the turmoil of the acute stage, screening for maladjustment or maladaptive behavior of children and parents, providing counseling, and referring the children and family for more specialized mental health input when indicated.

Adaptation, Psychological↗
PubMed1988

The impact of pediatric asthma education on morbidity. Assessing the evidence.

We reviewed the literature evaluating pediatric asthma education interventions to assess their impact on morbidity (school absences and health care utilization). Thirteen studies were analyzed, most of which reported favorable outcomes. Of the ten studies reporting on school absences, only seven used tests of statistical significance when reporting on postintervention reductions, and of those, only two found a significant decrease in absenteeism. Similarly, among the studies reporting on utilization, not all used tests of statistical significance when reporting on postintervention decreases in physician visits, ER visits, and hospitalization. Only four of the ten studies used adequate sample sizes to detect a 20 percent reduction in school absences, and stratification of the sample by severity of asthma suggests that some programs do reduce health care utilization among those children with more severe disease. We conclude that the effectiveness of asthma educational programs on reducing school absences and health care utilization may be small. These programs are best directed toward children with moderate or severe disease. Finally, it is important for pediatricians, children with asthma, and their families to have realistic expectations about what these programs may accomplish.

Absenteeism↗
PubMed1980

Serum cortisol response to acute myocardial infarction in the aged.

The adrenocortical response to acute myocardial infarction in aged patients was studied by measuring serum cortisol concentration (radioimmunoassay) at the time of hospital admission. The mean serum cortisol level in 9 patients over 80 years old was similar to that in 5 patients less than 60 years old. In all patients who died, or in whom shock developed, the serum cortisol concentration was significantly elevated.

Acute Disease↗
PubMed1976

GABA and glycine transport in frog CNS: high affinity uptake and potassium-evoked release in vitro.

Slices of frog cerebrum, optic tectum, medulla and spinal cord rapidly accumulate [3H]GABA and [3H]glycine from the surrounding medium so that after 10 min tissue:medium ratios as high as 113 for GABA (optic tectum) and 18.5 for glycine (medulla) may be achieved. Kinetic analysis revealed two distinct saturable uptake systems for each amino acid in the 4 CNS areas. The high affinity systems (apparent Km: 9-22 muM for GABA; 5-35 muM for glycine) required sodium ions in the medium and were relatively substrate specific. Significant release of [3H]GABA and [3H]glycine, but not of L-[3H]leucine, was evoked by exposure to medium containing potassium ions in a concentration of 40 mM. The process of release was calcium-dependent. The importance of these results with regard to the roles of GABA and glycine as neurotransmitters in both spinal and supraspinal levels of the amphibian neuraxis is discussed.

Alanine↗