Dental problems and Familismo: social network discussion of oral health issues among adults of Mexican origin living in the Midwest United States.

OBJECTIVE: To examine the influence of collectivist orientation (often called familismo when applied to the Latino sub-group in the United States) in oral health discussion networks. BASIC RESEARCH DESIGN: Through respondent-driven sampling and face-to-face interviews, we identified respondents' (egos) personal social network members (alters). Egos stated whom they talked with about oral health, and how often they discussed dental problems in the preceding 12 months. PARTICIPANTS: An urban community of adult Mexican-American immigrants in the Midwest United States. We interviewed 332 egos (90% born in Mexico); egos named an average of 3.9 alters in their networks, 1,299 in total. METHOD: We applied egocentric network methods to examine the ego, alter, and network variables that characterize health discussion networks. RESULTS: Kin were most often leveraged when dental problems arose; egos relied on individuals whom they perceive to have better knowledge about dental matters. However, reliance on knowledgeable alters decreased among egos with greater behavioral acculturation. CONCLUSIONS: This paper developed a network-based conceptualization of familismo. We describe the structure of oral health networks, including kin, fictive kin, peers, and health professionals, and examine how networks and acculturation help shape oral health among these Mexican-Americans.

GnRH treatment at artificial insemination in beef cattle fails to increase plasma progesterone concentrations or pregnancy rates.

Treatment with GnRH at the onset of standing estrus increased pregnancy percentages and circulating concentrations of progesterone in repeat breeder dairy cows. The objective of this study was to determine the effect of treatment with GnRH at AI on concentrations of progesterone and conception rates in beef cattle that exhibited estrus. Two hundred ninety-three heifers at four locations were synchronized with the Select Synch plus CIDR protocol (given GnRH and a CIDR was placed into the vagina, and 7 d later, given PGF(2alpha) and CIDR removed; n=253) or the 14-19 melengestrol acetate (MGA) protocol (MGA fed at 0.5mg/head/d for 14 d, with PGF(2alpha) 19 d after MGA withdrawal n=40) and AI was done after detection of estrus. At Location 1, blood samples were collected on Day 2, 4, 6, 10, 15, and 18 after AI (Day 0=AI). Two hundred and fifty postpartum cows at two locations were synchronized with the Select Synch plus CIDR protocol, and AI was performed after detection of estrus. At AI, cattle were alternately assigned to one of two treatments: (1) treatment with GnRH (100microg) at AI (n=127 heifers and n=108 cows); or (2) non-treated control (n=120 heifers and n=119 cows). Concentrations of progesterone tended to be greater in control heifers compared to GnRH-treated heifers on Days 6 (P=0.08), 10 (P=0.07), and 15 (P=0.11). Overall conception rates were 68% and 66% for GnRH treated and control, respectively, and were not different between treatments (P=0.72). In summary, treatment with GnRH at time of AI had no influence on conception rates in cattle that had exhibited estrus.

Effect of preovulatory concentrations of estradiol and initiation of standing estrus on uterine pH in beef cows.

Previous studies have indicated that initiation of standing estrus within 24h of fixed-time AI influenced pregnancy rates. Furthermore, uterine environment at time of insemination can influence sperm transport. We hypothesized that preovulatory concentrations of estradiol would influence uterine pH at time of insemination. The objective of this study was to determine the influence of elevated preovulatory concentrations of estradiol on uterine pH following a fixed-time AI protocol. Cows were synchronized with the CO-Synch (n=57) protocol, and 29 cows were treated with an injection of estradiol cypionate (ECP; 1mg) 36h before the second injection of GnRH. Cows that exhibited standing estrus or were treated with ECP had increased (P<0.05) concentrations of estradiol compared to cows not in estrus and not administered ECP, respectively. There was an ECP by standing estrus interaction on uterine pH (P=0.01). Control cows that exhibited estrus had a reduced uterine pH (6.72+/-0.10; P=0.05) compared to control cows not exhibiting estrus (7.0+/-0.06). Cows treated with ECP and detected in standing estrus had a greater uterine pH (7.0+/-0.07) compared to control cows in estrus (P=0.02) and ECP cows not in estrus (6.81+/-0.09; P=0.06). The interval between the initiation of standing estrus and when pH was determined also influenced uterine pH. Cows that initiated standing estrus within 4h of pH determination had a lower uterine pH (6.74+/-0.12) compared to cows that initiated estrus 4-8h (7.09+/-0.08; P=0.07) or 8-12h (7.10+/-0.15; P=0.03) after pH determination. In summary, elevated concentrations of estradiol influenced standing estrus but only influenced uterine pH when pH was determined within 4h of the initiation of standing estrus.

At the intersection of lay and professional social networks: how community ties shape perceptions of mental health treatment providers.

BACKGROUND: The therapeutic alliance is a critical determinant of individuals' persistence and outcomes in mental health treatment. Simultaneously, individuals' community networks shape decisions about whether, when, and what kind of treatment are used. Despite the similar focus on social relationship influence for individuals with serious mental illness, each line of research has maintained an almost exclusive focus on either 'inside' (i.e. treatment) networks or 'outside' (i.e. community) networks, respectively. METHOD: For this study, we integrate these important insights by employing a network-embedded approach to understand the therapeutic alliance. Using data from the Indianapolis Network Mental Health Study (INMHS, n = 169, obs = 2206), we target patients experiencing their first major contact with the mental health treatment system. We compare patients' perceptions of support resources available through treatment providers and lay people, and ask whether evaluations of interpersonal dimensions of the therapeutic alliance are contingent on characteristics of community networks. RESULTS: Analyses reveal that providers make up only 9% of the whole social network, but are generally perceived positively. However, when community networks are characterized by close relationships and frequent contact, patients are significantly more likely to report that treatment providers offer useful advice and information. Conversely, when community networks are in conflict, perceptions of treatment providers are more negative. CONCLUSION: Community-based social networks are critical for understanding facilitators of and barriers to effective networks inside treatment, including the therapeutic alliance. Implications for community-based systems of care are discussed in the context of the USA and global patterns of deinstitutionalization and community reintegration.

Psychological and behavioral acculturation in a social network of Mexican Americans in the United States and use of dental services.

OBJECTIVES: We used data from the TalaSurvey study to examine associations between dental health experiences, social network characteristics, and levels of behavioral and psychological acculturation in one location in the American Midwest. METHODS: Starting in parishes and community organizations, we identified adults of Mexican origin living in Indianapolis, who were 1st- or 2nd-generation immigrants from Tala, Mexico. Using a social networks methodology and following extensive formative research, we created an egocentric social network survey and administered it via face-to-face interviews. We identified the peers (alters) in interviewees' (egos) personal networks. We asked egos about multiple oral health and dental care variables for self and for alters. Acculturation (psychological and behavioral) was measured with a validated tool. Through logistic and negative binomial regression, we examined the effects of acculturation and network composition on ego's dental insurance status, dental office visits, and the reason for most recent dental office visit. RESULTS: A total of 332 egos (mean age 36; 63% female) were interviewed: 90% were born in Mexico; 45% had completed elementary school or lower; and most had low income. Each ego named 3.9 (SD±1.9) alters in his/her personal network, for a total of 1299 alters (mean age 39; 61% female). Both behavioral acculturation and psychological acculturation were moderately associated with dental insurance coverage, and greater behavioral acculturation predicted more frequent dental care. More psychologically acculturated egos were more likely to seek preventive care. Further, egos with more highly educated networks sought care more frequently and for preventive purposes, net of ego's own education and acculturation. CONCLUSIONS: This study contextualizes acculturation of Mexican Americans within the personal networks in which oral health discussion takes place. The findings underscore the critical importance of acculturation and social network factors in shaping a subgroup of Latinos' orientation toward dental care.

Estimation of pulmonary/systemic resistance ratios from echocardiographic systolic time intervals in young patients with congenital or acquired heard disease.

Previous work has shown the positive correlation of echocardiographic right ventricular preejection period/right ventricular ejection time ratio (RPEP/RVET) with pulmonary vascular resistance and pulmonary arterial diastolic pressure obtained at cardiac catheterization. However, the correlation was insufficient to predict pulmonary arterial diastolic pressure or vascular resistance from a given RPEP/RVET ratio. In this study the RPEP/RVET ratio was compared with left ventricular preejection period/ejection time ratio (LVEP/LVET) in 25 patients undergoing cardiac catheterization, and a strong correlation was found between the ratio (RPEP/RVET)/(LPEP/LVET) = R/L and the ratio of pulmonary arteriolar resistance/systemic arteriolar resistance (PAR/RS), especially when R/L was correlated with log10 PAR/RS (r = 0.902). A very high correlation (r = 0.960) was found between R/L and log10 PAR/RS when the group was restricted to patients with a ventricular septal defect or a complete endocardial cushion defect. Regression equations for prediction of PAR/RS have been derived for the various groups.

Surgical and medical results of complete atrioventricular canal: a ten year review.

The files of 121 patients who presented to Children's Hospital of Michigan over the last 10 years with complete atrioventricular (AV) canal were reviewed to evaluate long-term management and overall outcome. Of 121 patients, 70 underwent corrective surgery, 21 (30%) of whom died perioperatively. The surgical mortality rate was 13% when patients with hypoplastic left or right ventricle (n = 6), double-orifice mitral valve or extreme deficiency of mitral tissue (n = 5), and pulmonary vascular obstructive disease (n = 5) were excluded. Of the 49 patients who survived operation, 36 are in New York Heart Association class I, 1 patient requires a pacemaker and 3 died late. In 34 of the 51 patients (28%) who did not undergo operation, pulmonary vascular obstructive disease developed; it occurred within 12 months in 10 patients (8%). Eight other patients who did not undergo operation died before planned surgery (age 1 to 9 months). Although surgical prognosis in good candidates is acceptable, the overall prognosis for children with complete AV canal is guarded because of the risk of early death or early pulmonary vascular obstructive disease and frequently unfavorable anatomy.

Ventricular septal defect: results after repair in infancy.

During the 19 years from 1957 through 1975, there have been 106 patients under age 2 years who have undergone surgery for repair of a large ventricular septal defect at the University of Michigan Medical Center. The majority of the patients had either severe pulmonary hypertension or intractable congestive heart failure. Eighty-three infants survived operation; there has been one late death. The greatest mortality occurred in patients under age 6 months and in those with severe pulmonary hypertension. Surviving infants showed marked symptomatic improvement and change in growth patterns. Complications included the development of complete right bundle branch blodk or left anterior hemiblock in approximately 50 percent of patients and, in one instance, complete atrioventricular block. Forty-five patients have undergone cardiac catheterization 1 to 8 years postoperatively. Although 17 were found to have residual septal defects only 3 of these had a pulmonary to systemic flow ratio of 1.5:1 or more, and reoperation was accomplished without incident in these 3 patients and in 3 others with smaller shunts. With one exception, postoperative pulmonary arterial pressures and pulmonary to systemic vascular resistance ratios were normal or near normal, thus representing a significant contrast with findings in patients operated on after age 2 years. Whereas the complications of surgery appear no greater in the infant than in the older patient, many of the benefits can be realized only with operation at the earlier age.

Early and late results of total correction of tetralogy of Fallot.

Two hundred and nine patients underwent total repair of tetralogy of Fallot without congenital pulmonary atresia from 1971 to 1979. The age of the patients ranged from 22 months to 27 years (mean 6.8 years). Previous palliative shunts were present in 130 patients (62.2%). The right ventricular outflow tract obstruction was relieved by infundibulectomy in 31 patients (14.8%), by transannular patching in 142 patients (67.9%), and by insertion of a right ventricular--to--pulmonary artery prosthetic conduit in 10 patients (4.7%) with associated coronary artery anomalies. A porcine valve was inserted after transannular patching only in patients with undersized pulmonary arteries, unilateral pulmonary artery, or congenitally absent pulmonary valve. There were 10 early postoperative deaths (4.7%). Previous palliative shunts did not adversely affect early postoperative mortality rate. Surgically induced permanent complete heart block occurred in one patient (0.4%). Six patients (3%) died in the late postoperative period, three of them of unrelated causes. Late results were good in 170 patients (87%), fair in 10 patients (5.1%), and poor in 15 patients (7.6%). Poor results were due to residual stenosis at the origin of the pulmonary arteries in 13 patients (6.5%) and to residual ventricular septal defect in two patients (1%). The mean cardiothoracic ratio was 0.61 for patients with poor results and 0.54 for the entire group. Pulmonary valvular insufficiency was well tolerated postoperatively in the absence of distal pulmonary artery obstruction. This experience supports a policy of aggressive relief of the right ventricular outflow tract obstruction including liberal use of transannular patching and, when indicated, extensive reconstruction of the pulmonary artery branches. We also recommend a two-stage treatment program for symptomatic infants with unfavorable anatomy consisting of initial Blalock-Taussig shunt followed by total repair at about 3 years of age.

Classic shunting operations for congenital cyanotic heart defects.

A total of 297 consecutive classic systemic artery-pulmonary artery shunts were performed in 281 patients over the past 9 years. This experience includes 200 Blalock-Taussig shunts (67.3%), 84 Waterston shunts (28.2%), and 13 Potts shunts (4.3%). The overall early mortality after the Blalock-Taussig shunt (5.5%) was significantly lower (p less than 0.02) than for the Waterston shunt (13%). The early mortality after either the Blalock-Taussig or Waterston shunt was not statistically related to the age of the patient at operation. Both the Blalock-Taussig and Waterston shunts demonstrated a higher mortality (p less than 0.02) among patients in Group II (complex defects) than in patients in Group I (tetralogy of Fallot and pulmonary atresia with ventricular septal defect [VSD]). However, the Blalock-Taussig shunt had a significantly lower (p less than 0.04) probability of early postoperative death than the Waterston shunt among patients with complex lesions. The Blalock-Taussig shunt also revealed a lower incidence of important late postoperative complications and did not affect adversely the hemodynamic result after intracardiac correction, as evidenced by late postoperative cardiac catheterization. This study also confirms the feasibility of the Blalock-Taussig shunt during the neonatal period without significantly increased age-related risk of postoperative death (p = 0.13) and with good early and late long-term patency rates.

Results of the Mustard operation for dextro-transposition of the great arteries.

One hundred twenty patients with dextro-transposition of the great arteries (TGA) underwent intra-arterial baffle repair using thin Dacron fabric from 1971 to 1979. The ages of the patients ranging from 29 days to 17 years (mean age 28 months). Thirty-five patients had undergone 49 preliminary palliative operations. Early postoperative mortality was 4.8% for patients with simple TGA but was higher among patients with associated ventricular septal defect (26%), VSD and left ventricular outflow tract obstruction (28.5%) and intact ventricular septum with left ventricular outflow tract obstruction (12.5%). Early nonfatal postoperative complications included low cardiac output (23.3%), respiratory insufficiency (35.8%), junctional rhythm (34.1%), superior vena caval (SVC) obstruction (9.1%), and chylothorax (7.5%). Late postoperative mortality for all groups was 7.5% (nine patients). Late cardiac dysrhythmias occurred in 33 patients (40.7%). Normal sinus rhythm has been preserved in all patients since direct, high SVC cannulation was instituted. Late postoperative hemodynamic and angiographic evaluation in 61 patients revealed severe to total SVC obstruction in 12 patients (20.2%) and pulmonary venous obstruction in four patients (6.5%). Among the latter, two patients died following reoperation and another patient died without operation. SVC obstruction was clinically important in only three patients, two of whom have undergone successful reoperation. All other late survivors are acyanotic and clinically well. The Mustard operation has dramatically improved the survival rate and quality of life for patients with TGA. However, postoperative caval and pulmonary venous obstruction are problems which require additional technical modifications and stimulate the search for alternative corrective operations.

Down's syndrome, complete atrioventricular canal, and pulmonary vascular obstructive disease.

We reviewed our experience over a 10-year period to determine whether children with Down's syndrome and complete atrioventricular canal develop pulmonary vascular obstructive disease earlier than children with normal chromosomes and this defect. Comparisons were made between Down's syndrome and normal chromosome children regarding (1) pulmonary blood flow and pulmonary vascular resistance at initial catheterization, (2) operability as related to elevation in pulmonary vascular resistance, and (3) age at diagnosis of fixed pulmonary vascular obstructive disease. The 45 patients with Down's syndrome catheterized under 1 year of age had a lower mean pulmonary blood flow (3.2 versus 5.7; p = 0.0001) and higher mean pulmonary vascular resistance (8.3 versus 4.6 Wood units.m2; p = 0.0003) than their 34 normal chromosome counterparts. When all ages were included, 38 of 81 (47%) of the children with Down's syndrome and 32 of 40 (80%) of the normal children were considered operable. Non-Down's syndrome patients who had operations had a higher pulmonary blood flow (5.8 versus 3.3; p = 0.004) and lower pulmonary vascular resistance (3.6 versus 6.0 Wood units.m2; p = 0.005) than Down's syndrome patients. Of the 34 patients who did not have operations because of pulmonary vascular obstructive disease, 31 had Down's syndrome. In 10 of 81 children with Down's syndrome, fixed pulmonary vascular obstructive disease was diagnosed before the age of 1 year, while this was found in none of 40 normal children. Our data demonstrate that Down's syndrome patients with complete atrioventricular canal have a greater degree of elevation of pulmonary vascular resistance in the first year of life and more rapid progression to fixed pulmonary vascular obstructive disease than children with normal chromosomes.

Surgical treatment of cor triatriatum.

Six patients with cor triatriatum underwent surgical correction. They ranged for 1.5 to 93 months old (mean, 22 months). Congestive heart failure was present in 3 patients. Cardiomegaly and increased pulmonary vascularity were evident roentgenographically in all patients. Cardiac cineangiography demonstrated the subdividing left atrial membrane in 5 patients and suggested the correct diagnosis by revealing an abnormal configuration of the left atrium in the other patient. The opening in the anomalous left atrial membrane was stenotic in every instance. The proximal left atrial chamber communicated with the right atrium through an atrial septal defect in 5 patients and with the systemic venous circuit through a persistent left superior vena cava in the other patient, in whom the atrial septum was intact. A right atrial-transseptal approach provided ample exposure for complete excision of the obstructing membrane and repair of the atrial septum in all patients. One patient died of low cardiac output during the early postoperative period. The other 5 are alive and well at an average of 48 months after operation.

Where your patients are.

Thomas Jefferson University Hospital conducted qualitative research to determine consumers' attitudes toward allopathic and alternative medicine. Results suggest that patients undergoing both allopathic and alternative treatment simultaneously often do not trust their allopathic physicians enough to discuss their alternative treatment.

Relationship of follicle size and concentrations of estradiol among cows exhibiting or not exhibiting estrus during a fixed-time AI protocol.

Cows exhibiting estrus near fixed-time artificial insemination (AI) had greater pregnancy success than cows not showing estrus. The objective of this study was to determine the relationship between follicle size and peak estradiol concentration between cows that did or did not exhibit estrus during a fixed-time AI protocol. Ovulation was synchronized in beef cows by applying the CO-Synch protocol [GnRH (100 µg) on day-9, prostaglandin F2α (PGF2α; 25 mg) on day-2, and a second injection of GnRH 48 h after PGF2α (day 0)] to both suckled (experiment 1) and nonsuckled (experiment 2) cows. Follicle size (day 0) and ovulation (day 2) was determined by ultrasonography. Blood samples were collected every 3 or 4 h beginning at the time of PGF2α injection (0 h). Estrus was detected by visual observation with the aid of estrus-detection patches, and cows that ovulated were classified as exhibited estrus (n = 46) or did not exhibit estrus (n = 63). In both suckled and nonsuckled cows, there was a positive relationship between all cows (P < 0.05) and among those that exhibited estrus (P < 0.05) between follicle size and peak estradiol concentration, but no linear relationship (P > 0.50) between follicle size and peak estradiol concentration was observed among cows not exhibiting estrus. Cows that exhibited estrus had greater (P < 0.01) peak estradiol concentrations than cows that did not exhibit estrus. Suckled cows exhibiting standing estrus had greater (P < 0.001) preovulatory concentrations of estradiol beginning 6 h (replicate 1) or 4 h (replicate 2) after the injection of PGF2α on day-2 compared with cows not exhibiting standing estrus. Nonsuckled cows exhibiting standing estrus had greater (P < 0.001) preovulatory concentrations of estradiol beginning at the injection of PGF2α on day-2 compared with cows not exhibiting standing estrus. Furthermore, cows that exhibited estrus had an increased (P < 0.01) rate in the rise in concentrations of estradiol following the PGF2α to peak estradiol than cows not exhibiting estrus. In summary, follicle diameter had a positive relationship with peak concentrations of estradiol, but only among cows that exhibited standing estrus, and estradiol increased earlier in cows that exhibited estrus compared with cows that did not.

Influence of inducing luteal regression before a modified fixed-time artificial insemination protocol in postpartum beef cows on pregnancy success.

Most fixed-time insemination protocols utilize an injection of GnRH at the beginning of the protocol to initiate a new follicular wave. However, the ability of GnRH to initiate a new follicular wave is dependent on the stage of the estrous cycle. We hypothesized that administering PGF(2α) 3 d before initiating a fixed-time AI protocol would improve synchrony of follicular waves and result in greater pregnancy success. Therefore, our objective was to determine whether inducing luteal regression 3 d before a fixed-time AI protocol would improve control of follicular turnover and pregnancy success to fixed-time AI. Multiparous crossbred cows at 3 locations (n = 108, 296, and 97) were randomly assigned to 1 of 2 treatments: 1) PGF(2α) [25 mg; intramuscularly (i.m.)] on d -9, GnRH (100 µg; i.m.) and insertion of a controlled internal drug-releasing device (CIDR) on d -6, PGF(2α) (25 mg; i.m.) and CIDR removal with PGF(2α) (25 mg; i.m.) at CIDR removal on d 0 (PG-CIDR) or 2) GnRH (100 µg; i.m.) and insertion of a CIDR on d -5 and CIDR removal with PGF(2α) (25 mg; i.m.) at CIDR removal and 4 to 6 h after CIDR removal (5-d CIDR). Cows were time-inseminated between 66 and 72 h (PG-CIDR) or 70 to 74 h (5-d CIDR) after CIDR removal, and GnRH was administered at the time of fixed-time AI. At location 1, ovulatory response to the first injection of GnRH was determined by ultrasonography at the time of GnRH and 48 h after GnRH administration. Among cows with follicles ≥10 mm in diameter, more (P = 0.03) PG-CIDR-treated cows ovulated after the initial GnRH injection (88%, 43/49) compared with the 5-d CIDR-treated cows (68%, 34/50). Pregnancy outcome was not influenced by location (P = 0.96), age of the animal (P = 1.0), cycling status (P = 0.99), BCS (P = 1.0), or any 2-way interactions (P ≥ 0.13). However, pregnancy success was influenced by synchronization protocol (P = 0.04). Pregnancy outcome was greater (P = 0.04) for the PG-CIDR protocol (64%) compared with the 5-d CIDR protocol (55%). In summary, control of follicular turnover was improved by inducing luteal regression 3 d before initiation of a fixed-time AI protocol, and pregnancy success was improved with the PG-CIDR protocol compared with the 5-d protocol.

Influence of standing estrus before an injection of GnRH during a beef cattle fixed-time AI protocol on LH release, subsequent concentrations of progesterone, and steriodogenic enzyme expression.

Beef cows that exhibit estrus before fixed-time AI have been reported to have increased pregnancy success and increased concentrations of progesterone during the subsequent estrous cycle. Therefore, these experiments were conducted to evaluate if initiation of standing estrus before an injection of GnRH during a fixed-time AI protocol affected LH pulses, subsequent concentrations of progesterone, and luteal steroidogenic enzyme expression. In Experiments 1 and 2, cows were treated with the CO-Synch protocol (100 µg GnRH day -9, 25 mg PGF(2α) day -2, and 100 µg GnRH day 0) and allotted to one of two treatments: 1) cows that initiated estrus before GnRH on day 0 (estrus; n = 5) or 2) cows that did not initiate estrus and were induced to ovulate by the GnRH on day 0 (no estrus; n = 5). In Experiment 1, blood samples were collected at 15-min intervals from 0 to 6 (bleed 1), 12 to 20 (bleed 2), 26 to 34 (bleed 3), and 40 to 48 (bleed 4) h after GnRH. Daily blood samples were collected for 17 d. Initiation of estrus before the GnRH injection had no effect on LH release or the pattern of progesterone increase; however, cows detected in estrus had overall increased (P = 0.002) concentrations of progesterone compared with cows not in estrus. In Experiment 2, estrus was detected with the HeatWatch system. Location and size of the ovulatory follicle was determined on day 0 by transrectal ultrasonography at time of injection with GnRH. Blood samples were collected on days 3, 4, 5, 7, and 9; luteal tissue was collected on day 10 (n = 4 estrus and n = 9 no estrus) from corpus luteum (CL) originating from similar-sized follicles (13.0 to 16.0 mm). Total cellular RNA was extracted, and relative mRNA levels were determined by real-time reverse transcription PCR and corrected for GAPDH. There was no effect of estrus on CL weight or concentrations of progesterone. In addition, there was no effect of estrus, follicle size, or CL weight on luteal expression of LH receptor, StAR, CYP11A1, or 3ßHSD. However, there was a correlation between follicle size and CL weight (P = 0.01; R(2) = 0.43); for every increase of 1 mm in follicle size, CL weight increased by 1.5 g. In summary, estrus did not influence release of LH, CL weight, progesterone concentrations, or expression of steriodogenic enzymes. However, as follicle size increased, CL weight increased; therefore, both follicle size and CL weight were associated with progesterone concentrations.

Influence of inducing luteal regression before a modified controlled internal drug-releasing device treatment on control of follicular development.

At the initiation of most controlled internal drug-releasing (CIDR) device protocols, GnRH has been used to induce ovulation and reset follicular waves; however, its ability to initiate a new follicular wave is variable and dependent on stage of the estrous cycle. The objectives of the current studies were to determine 1) if inducing luteal regression before the injection of GnRH at time of insertion of a CIDR resulted in increased control of follicular development, and 2) if removing endogenous progesterone by inducing luteal regression before insertion of the CIDR decreased variation in LH pulse frequency. In Exp. 1 and 2, Angus-cross cycling beef heifers (n = 22 and 38, respectively) were allotted to 1 of 2 treatments: 1) heifers received an injection of PGF(2α) on d -3, an injection of GnRH and insertion of a CIDR on d 0, and a PGF(2α) injection and CIDR removal on d 6 (PG-CIDR) or 2) an injection of GnRH and insertion of a CIDR on d 0 and on d 7 an injection of PGF(2α) and removal of CIDR (Select Synch + CIDR). In Exp. 3, Angus-cross beef heifers (n = 15) were assigned to 1 of 3 treatments: 1) PG-CIDR; 2) PGF(2α) on d -3, GnRH on d 0, and PGF(2α) on d 6 (PG-No CIDR); or 3) Select Synch + CIDR. Follicular development and ovulatory response were determined by transrectal ultrasonography. Across all experiments, more (P = 0.02) heifers treated with PG before GnRH initiated a new follicular wave after the injection of GnRH compared with Select Synch + CIDR-treated heifers. In Exp. 1, after CIDR removal, interval to estrus did not differ (P = 0.18) between treatments; however, the variance for the interval to estrus was reduced (P < 0.01) in PG-CIDR heifers compared with Select Synch + CIDR heifers. In Exp. 3, there was a tendency (P = 0.09) for LH pulse frequency to be greater among PG-CIDR and PG-No CIDR compared with the Select Synch + CIDR, but area under the curve, mean LH concentrations, and mean amplitude did not differ (P > 0.76). In summary, induction of luteal regression before an injection of GnRH increased the percentage of heifers initiating a new follicular wave. Removal of endogenous progesterone tended to increase LH pulse frequency, and the modified treatment increased the synchrony of estrus after CIDR removal.