Effect of interval to resynchronization of ovulation on fertility of lactating Holstein cows when using transrectal ultrasonography or a pregnancy-associated glycoprotein enzyme-linked immunosorbent assay to diagnose pregnancy status.

The objective of this study was to compare 2 strategies for resynchronization of ovulation based on nonpregnant diagnoses using transrectal ultrasonography or a pregnancy-associated glycoprotein (PAG) ELISA. Lactating Holstein cows (n = 1,038) were submitted for first postpartum timed artificial insemination (TAI) using a Presynch + Ovsynch protocol. After the initial breeding, cows were randomly assigned to initiate resynchronization 25 d (D25) or 32 d (D32) later. Pregnancy status of cows initiating Resynch 25 d after TAI was determined 27 d after TAI by using a PAG ELISA, whereas pregnancy status of cows initiating Resynch 32 d after TAI was determined 39 d after TAI using transrectal ultrasonography. Cows diagnosed as not pregnant continued the Resynch protocol by receiving an injection of PGF(2 alpha) 7 d after the initial GnRH injection and a second GnRH injection 54 h after the PGF(2 alpha) injection. Cows in both treatments were inseminated approximately 16 h after the second GnRH injection. Blood samples for analysis of progesterone (P(4)) were collected at the first GnRH injection of each Resynch protocol. Pregnancies per AI (P/AI) of nonpregnant cows initiating Resynch 25 vs. 32 d after first postpartum TAI did not differ 39 d after TAI and were 28.3 vs. 30.9% for D25 vs. D32 cows, respectively. Mean P(4) at the first GnRH injection of Resynch was greater for D32 than for D25 cows (3.67 +/- 0.22 vs. 2.83 +/- 0.22 ng/mL), indicating that the Resynch treatments were initiated at different stages of the estrous cycle. After blocking P(4) concentration into low (<1.0 ng/mL) or high (>or=1.0 ng/mL) classes, P(4) class was not found to affect P/AI 39 d after TAI. Early resynchronization was not found to affect P/AI 39 d after TAI; however, early resynchronization did decrease days between inseminations and the interval from the initial nonpregnant diagnosis to conception. Earlier detection of nonpregnant cows using the PAG ELISA in conjunction with a TAI resynchronization program may improve the rate at which cows become pregnant in a dairy herd compared with transrectal ultrasonography conducted at a later stage after TAI.

Effects of sustained release bovine somatotropin (sometribove) on animal health in commercial dairy herds.

The health of dairy cows given bovine somatotropin (bST) for one lactation was evaluated in 28 commercial herds located in four regions of the United States. At least six herds were in a region and at least one herd/region contained fewer than 60 cows. Cows (n = 1213) were assigned randomly to control or bST groups and were treated beginning in wk 9 to 10 of lactation and every 14 d until dry-off or d 400 of lactation. Management was according to site practices. Cows were observed for health-related signs by farm personnel daily and by the herd veterinarian biweekly. Average 305-d test-day milk yields were 932 kg greater for bST-treated cows. Pregnancy rates, days open, twinning, cystic ovaries, or abortions were unaffected by treatments. Supplementation of cows with bST had no effect on total mastitis cases, total days of mastitis, duration of mastitis, or the odds ratio of a cow to develop mastitis. Cows supplemented with bST used more medications for health events other than mastitis. This usage was associated primarily with treatments for disorders of the foot and hock. Supplemented cows had a slight increase in foot disorders. There was no effect of supplementation with bST on culling from the herd or removal from study. Overall, the results confirm that label directions for bST are adequate for safe use under field conditions. All clinical signs observed in this study occur normally in dairy herds and were managed in cows supplemented with bST.

Effect of ischemic time on survival in clinical lung transplantation.

BACKGROUND: While there is convincing evidence that prolonged ischemic times correlate with reduced long-term survival in heart transplantation, the effect of ischemic time on outcome in clinical lung transplantation remains controversial. To assess the effect of ischemic time on outcomes in lung transplantation, we reviewed our experience. METHODS: The study was performed by retrospective chart review. RESULTS: First-time lung transplantation was performed on 392 patients between 1988 and 1998. All grafts were flushed with cold crystalloid preservation solution and stored on ice. Ischemic time data were available for 352 of 392 (90%) patients. Ischemic times were grouped as follows: 0 to 4 hours (n = 91), 4 to 6 hours (n = 201), more than 6 hours (n = 60). Ischemic time did not correlate with survival: 3-year actuarial survival = 56% (0 to 4 hours), 58% (4 to 6 hours), 68% (> 6 hours), p = 0.58. There was no significant difference in the incidence of biopsy-proven diffuse alveolar damage in the first 30 days after transplantation (31%, 32%, 38%), episodes of acute rejection in the first 100 days after transplantation (1.9, 1.8, 1.7), duration of intubation (median 3, 4, 3 days), or incidence of obliterative bronchiolitis (23%, 28%, 26%) between the three groups (0 to 4 hours, 4 to 6 hours, > 6 hours, respectively). A diagnosis of diffuse alveolar damage was associated with a significantly worse outcome (1-year survival = 82% versus 54%, p < 0.0001). CONCLUSIONS: In contrast to heart transplantation, pulmonary allograft ischemic time up to 9 hours does not appear to have a significant impact on early graft function or survival. The presence of diffuse alveolar damage on biopsy early after transplantation does not correlate with prolonged ischemic time, but is associated with substantially reduced posttransplantation survival.

Single- versus double-lung transplantation for pulmonary hypertension.

OBJECTIVES: Uncertainty persists as to the best lung transplant operation for patients with pulmonary hypertension. To quantify short- and long-term outcomes after single- and double-lung transplantation for pulmonary hypertension, we reviewed our clinical experience. METHODS: A retrospective review of 58 lung transplants at a single institution between 1989 and 1996 was performed. Recipients had primary (n = 19) or secondary (n = 39) pulmonary hypertension. RESULTS: Thirty-seven double- and 21 single-lung transplants were performed. The groups were well matched with regard to preoperative characteristics. Cardiopulmonary bypass time was longer (151 vs 250 minutes) in the double-lung group. Excluding 10 patients surviving less than 30 days (6 double- and 4 single-lung transplants), median duration of intubation (7.5 vs 10 days), length of stay in the intensive care unit (10 vs 16 days), and hospital stay (32 vs 52 days) were not significantly different for the single- and double-lung groups, respectively. Actuarial survival was nearly identical, with 81% and 84% 1-month survivals for the single- and double-lung groups, and identical 1-year (67%) and 4-year (57%) survivals for both groups. Late functional status was similar for recipients of single- and double-lung grafts. During the period of this study, 58 patients with pulmonary hypertension died on our center's waiting list before coming to transplantation. CONCLUSIONS: These data suggest that lung transplant recipients with pulmonary hypertension have similar outcomes after single- or double-lung transplantation. These results support cautious preferential application of single-lung transplantation for pulmonary hypertension.

Safe laparoendoscopic approach to biliary pancreatitis in older patients.

OBJECTIVE: To evaluate management strategies for biliary pancreatitis in different age groups. DESIGN: Retrospective review. SETTING: Large private metropolitan teaching hospital. PATIENTS: Patients seen between January 1991 and December 1994 with a diagnosis of biliary pancreatitis (N = 136) divided into 2 groups (group 1, aged < 65 years; group 2, aged > or = 65 years). INTERVENTIONS: Primary treatments included endoscopic retrograde cholangiography (n = 36) alone or with endoscopic sphincterotomy (n = 27); operative procedures, including cholecystectomy by laparoscopic (n = 54) or open (n = 16) approaches; or no definitive therapy (n = 22). Secondary treatments of common bile duct stones included laparoscopic transcystic bile duct exploration (n = 5), open common bile duct exploration (n = 4), or postoperative endoscopic retrograde cholangiography (n = 10). MAIN OUTCOME MEASURES: Success of interventions, incidence and treatment of common bile duct stones, morbidity and mortality rates, frequency of retained stones, and length of hospitalization. RESULTS: Numbers of Ranson criteria were higher for older patients (group 1, 0.83 +/- 0.12 vs group 2, 1.57 +/- 0.11 [mean +/- SEM]; P < .001). Primary endoscopic retrograde cholangiography with or without endoscopic sphincterotomy was performed earlier than operative procedures, with a significantly higher incidence of common bile duct stones (72% vs 19%; P < .001). Number of primary procedures and complication and mortality rates for endoscopic retrograde cholangiography with or without endoscopic sphincterotomy were 36, 8%, and 3%, respectively; for laparoscopic cholecystectomy, 54, 9%, and 2%, respectively; and for open cholecystectomy, 16, 6%, and 19%, respectively. For complication and mortality rates, there were no statistical differences between groups or among treatments. Deferred therapy was used in 30 patients, with 20% readmitted for recurrence of biliary pancreatitis. Length of intensive care unit and total hospital stay were similar for all groups and treatments. CONCLUSIONS: Older patients with biliary pancreatitis may be safely treated with a combined laparoendoscopic approach. Management of common bile duct stones depends on age, with laparoscopic transcystic duct exploration or open common bile duct exploration preferred for younger patients and laparoscopic transcystic duct exploration or postoperative endoscopic sphincterotomy for older ones. Deferred therapy has a substantial relapse rate.

Continuing hazards of the learning curve in laparoscopic cholecystectomy.

Bile duct injury is one of the most serious complications of laparoscopic cholecystectomy (LC). In open cholecystectomy (OC) the reported incidence of injury is less than 0.2 per cent. In LC, the aggregate reported experience, in many thousands of cases, is three or four times this number. Although "the learning curve" has been considered the principal factor in the heightened incidence of this complication with LC, there are hazards inherent in this new surgical modality that may never allow elimination of the increased risk of bile duct injury. As a sequel to an earlier report of 1200 cases of OC before the laparoscopic era from a single institution, this report deals with the next 2427 consecutive cases of LC from the same institution. In the first 1284 cases of LC, there were seven bile duct injuries (0.58%); in the ensuing 1143 cases there were six bile duct injuries (0.50%). The overall incidence nationwide is even higher, as evidenced by widespread reports of repair of bile duct injuries referred to major tertiary care centers. Routine operative cholangiography is of the utmost importance in the early recognition and immediate repair of ductal injuries. In 12 of the 13 cases reported here, early recognition and repair during the primary surgery resulted in a successful outcome.

Stimulation of mammogenesis and lactogenesis by recombinant bovine placental lactogen in steroid-primed dairy heifers.

A model of induced lactation was modified to examine the effects of bovine prolactin (bPRL) and bovine placental lactogen (bPL) on mammary growth and differentiation. Thirty-two peripubertal, non-pregnant Holstein heifers were given daily s.c. injections of oestradiol (0.05 mg/kg) and progesterone (0.25 mg/kg) for 7 days to initiate mammary growth. Treatment with bromocriptine (40 mg/3 days) reduced serum PRL concentrations to approximately 25% of pretreatment levels, for the duration of the study. On the day following the last steroid injection, groups of eight heifers were given twice daily s.c. injections of either saline (negative control), recombinant bPRL (rbPRL; 80 mg/day) or recombinant bPL (rbPL; 80 and 160 mg/day) for 7 days. At the end of this period (day 15), growth and differentiation of the mammary glands were assessed. Treatment with rbPL increased total mammary DNA above control value by 50 and 60% for the 80 and 160 mg/day doses respectively. However, total DNA was not different for the control and rbPRL-treated groups. The blood serum concentration of alpha-lactalbumin was measured daily throughout the study and used as an index of mammary differentiation. Both rbPRL and rbPL stimulated mammary differentiation (i.e. induction of milk synthesis), although rbPRL appeared to be more potent than rbPL. These results indicate that rbPL is lactogenic in vivo and strongly suggest that bPL is a mammary mitogen.

Chemical synthesis of bovine transforming growth factor-alpha: synthesis, characterization and biological activity.

Bovine transforming growth factor-alpha (bTGF-alpha) is a 50 amino acid polypeptide with three disulfide linkages. In order to evaluate the biological function of this peptide, bTGF-alpha was synthesized via an automatic synthesizer and purified to homogeneity in high yield. The integrity of this synthetic peptide was confirmed by chemical analyses and bioassays. In a bovine liver radioreceptor assay, bTGF-alpha competes with radiolabeled EGF and has activity comparable to mEGF and hTGF-alpha. Compared to hEGF, bTGF-alpha elicits a greater response in a bovine mammary cell proliferation.

Purification and partial characterization of a bovine epidermal growth factor-like polypeptide.

A heterologous radioreceptor assay was developed to follow the purification of an EGF-like polypeptide from bovine kidney. Purification of the growth factor was facilitated by the use of a novel affinity column using fixed A431 cells attached to sephadex beads. The mol. wt. of the purified EGF-LP was estimated to be 5480 from the amino acid composition. The purified EGF-like polypeptide stimulated the proliferation of bovine mammary epithelial cells and appeared to be equipotent to mouse EGF. Available evidence suggests that the purified molecule is distinct from bovine TGF-alpha.

Isolation of genomic sequence encoding a biologically active bovine TGF-alpha protein.

Genomic clones encoding bovine TGF-alpha were identified by hybridization with probes derived from human TGF-alpha sequence. Nucleotide sequence of the clones predicts that mature bovine TGF-alpha is a 50 amino acid polypeptide which shares 96% and 92% homology with human and rat TGF-alpha, respectively. Bovine TGF-alpha with the predicted sequence was chemically synthesized and tested for activity. Synthetic bovine TGF-alpha competes in a radioreceptor assay with labelled mouse EGF with activity parallel to that of human TGF-alpha and mouse EGF. The mitogenic activity of bovine TGF-alpha is comparable to that of human EGF in causing proliferation of bovine mammary epithelial cells. An approximately 5.0 kilobase RNA transcript is observed in polyadenylated RNA from MDBK cells by Northern blot analysis. The polymerase chain reaction detects the presence of a TGF-alpha transcript in many bovine tissues. These data indicate that bovine TGF-alpha may be a normal regulator of cell growth in the bovine animal.

A novel system for mammary epithelial cell culture.

A method is described for the isolation and density gradient enrichment of mammary epithelial fragments from pregnant, nonlactating bovine tissue. Immunocytochemical analysis prior to and following culture revealed specific staining with antibodies to keratin, indicating that these cells are epithelial in nature. Fragments enriched for epithelium could be stored in liquid nitrogen for extended periods prior to culture. When cast within a three-dimensional matrix of collagen gel, the mammary fragments grew as branching, duct-like structures and displayed a 4-fold increase in cell number during 10 to 12 d of culture.

Collagen gel culture system and analysis of estrogen effects on mammary carcinogenesis.

The results obtained to date from studies dealing with the role of hormones, including estrogen, on growth of mammary epithelial cells inside the collagen gel are described. The collagen gel matrix culture system appears to be a suitable system to obtain in vivo-like effects of hormones on mammary cell in vitro. The results thus far indicate that prolactin along with progesterone or cortisol can stimulate mammary cell proliferation. Thus far, estrogen has not been found to be mitogenic in our in vitro system.