PubMed Health⌕ Search

Biomedical subjects

J R Gibbons

Publications and source records attributed to J R Gibbons.

At least 19 recordsLinked to original sources
PubMed1999

Follicular and FSH dynamics in ewes with a history of high and low ovulation rates.

Daily transrectal ultrasound scanning and twice-daily blood sampling were used to monitor the temporal relationships between FSH concentrations and follicle development during complete interovulatory intervals for ewes in which the ovulation rate in each of the 2 previous years was high or low (> or = 3 and < or = 2 ovulations, respectively). Follicles that reached > or = 5 mm were used to define a follicular wave and were tracked retrospectively to 3 mm (emergence). The hypothesis that FSH surges (identified with a computer program) and follicular waves (retrospectively determined based on ultrasound scanning) are temporally associated was supported in both groups by the emergence of an anovulatory or ovulatory follicular wave near the peak of an FSH surge. Further support for the hypothesis was a significant increase in FSH concentrations before and a significant decrease after follicular-wave emergence in both groups independent of the identification of FSH surges. Ewes with a history of high ovulation rates had smaller follicles (anovulatory and ovulatory) and more ovulations, but the 2 groups were similar in the number of ovulatory follicular waves and associated FSH surges, number and characteristics of the FSH surges, and mean FSH concentrations per interovulatory interval. Surges of FSH were periodic (every 3 or 4 d) regardless of the ovulation-rate group or follicle response. In ewes with a low ovulation rate, the nonovulatory FSH surges were most frequently associated with emergence of detected anovulatory follicular waves. In ewes with a high ovulation rate, more FSH surges were not associated with a detected follicular wave, as defined, presumably because the largest follicle did not reach 5 mm. The results indicated that the factors resulting in a high ovulation rate were not exerted through circulatory patterns or concentrations of FSH but involved a shorter growth phase and smaller maximal diameter of follicles.

Animals↗
PubMed1999

Effects of ultrasound-guided transvaginal follicular aspiration on oocyte recovery and hormonal profiles before and after GnRH treatment.

Endocrine changes and recovered oocytes were evaluated during 16 wk of ultrasound-guided transvaginal follicular aspiration (TVFA) and prior to and following administration of GnRH at the cessation of aspiration. Nonlactating previously aspirated (PAC, n = 4) and non-aspirated, (AC, n = 4) Holstein cows were subjected to 16 wk of twice-weekly aspiration. Four control cows (OAC) were aspirated 1 time only at the final TVFA session (wk 16). Jugular blood samples were collected from all cows during aspiration, before and after the final TVFA session, and during an 18-d period following cessation of aspiration. Ovarian activity was monitored in all cows after cessation of aspiration for 18 d. The PAC and AC cows averaged 3.4 +/- 1.2 (+/- SE) and 6.8 +/- 1.2 oocytes per session, respectively. Progesterone concentrations during TVFA did not differ between the PAC and AC (0.8 +/- 0.1 and 0.9 +/- 0.1 ng/mL, respectively). Progesterone concentration in OAC was 4.5 +/- 0.2 ng/mL before TVFA, while the PAC and AC averaged 0.5 +/- 0.2 and 0.3 +/- 0.2 ng/mL, respectively, at 16 wk. At Week 16 LH was 1.0 +/- 0.2 ng/mL and it increased to 7.5 +/- 0.1 ng/mL after GnRH treatment. The LH concentration before the final aspiration session was higher at peak amplitude in PAC than in AC groups and peak length was longer in OAC than in AC cows (P < 0.07). Between 18 and 24 h after the last aspiration there were more LH peaks and greater peak frequencies in PAC than in OAC cows (P < 0.07), and the interval between peaks was longer in PAC and AC cows (P < 0.10) than in OAC cows. Mean FSH concentrations were lower (P < 0.01) for OAC than for PAC and AC groups at 20 and 24 h after the last aspiration. Follicle numbers after GnRH varied most among treatment groups for follicles < 9 mm, with the PAC, AC and OAC averaging 5.1 +/- 1.0, 5.1 +/- 1.0, and 3.8 +/- 1.0 follicles/d, respectively. Progesterone concentrations increased to 1.1 +/- 0.3 ng/mL in PAC cows and 2.5 +/- 0.3 and 3.4 +/- 0.3 ng/mL in AC and OAC groups, respectively, during the 18-d period. These results suggest that long-term TVFA affects progesterone, LH and FSH profiles and ovarian dynamics in cows.

Animals↗
PubMed1999

Relationship between follicular development and the decline in the follicle-stimulating hormone surge in heifers.

Experiment 1 was conducted to determine whether progesterone affects the pattern of the FSH surge or follicular development associated with a follicular wave in heifers. On Day 7 (Day 0 = ovulation), heifers were allocated into a group receiving prostaglandin F2alpha (PGF2alpha; n = 6) or a control group (n = 5). Twenty-four hours later, all detectable follicles (>/= 2 mm) were ablated (Hour 0). Follicular development was monitored Hours 0, 3, 6, 9, 12, and 16, at 8-h intervals thereafter until Hour 112. To monitor FSH concentrations, blood was sampled at Hours -24, 0, 3, 6, 9, 12, and 16, and at 8-h intervals thereafter until Hour 104. There were no differences (p > 0.05) between the PGF2alpha-treated group and controls in the patterns of the FSH surge or follicular development. Experiment 2 tested the hypothesis that 3-mm follicles do not have FSH-suppressing capacity and that suppression increases as follicles grow beyond 5 mm. Twenty-four hours after an injection of PGF2alpha (Days 6-8), heifers were subjected to either ablation of follicles >/= 2 mm or ovariectomy. Intact heifers were allocated into four groups (n = 5) in which all follicles of the new wave were ablated upon reaching either 3, 5, or 7 mm or were not ablated (controls). Blood was sampled at 8-h intervals to monitor FSH and estradiol-17beta. Averaged over Hours 8-120, FSH concentrations (ng/ml) were higher (p < 0.05) in the ovariectomized (2.02 +/- 0.05) and the 3-mm groups (1.91 +/- 0.05) than in the 5-mm (1.52 +/- 0.05), 7-mm (1.35 +/- 0.04), and control groups (1.33 +/- 0.05); and estradiol concentrations (pg/ml) were lower (p < 0.05) in the ovariectomized group (0.19 +/- 0.03) than in the 3-mm (1.48 +/- 0. 16), 5-mm (1.56 +/- 0.15), 7-mm (2.22 +/- 0.27), and control groups (2.55 +/- 0.49). In conclusion, the presence of endogenous progesterone did not affect FSH patterns or follicular development. Follicles </= 3 mm had no detectable capacity to suppress FSH. As follicles grew from 3 to 5 mm, they gained the capacity to suppress FSH; however, as follicles grew beyond 5 mm, FSH-suppressing capacity did not increase. The FSH decline was not attributable to an increase in circulating estradiol.

Animals↗
PubMed1999

Effect of thoracotomy and lung resection on exercise capacity in patients with lung cancer.

BACKGROUND: Resection is the treatment of choice for lung cancer, but may cause impaired cardiopulmonary function with an adverse effect on quality of life. Few studies have considered the effects of thoracotomy alone on lung function, and whether the operation itself can impair subsequent exercise capacity. METHODS: Patients being considered for lung resection (n = 106) underwent full static and dynamic pulmonary function testing which was repeated 3-6 months after surgery (n = 53). RESULTS: Thoracotomy alone (n = 13) produced a reduction in forced expiratory volume in one second (FEV1; mean (SE) 2.10 (0.16) versus 1.87 (0.15) l; p<0.05). Wedge resection (n = 13) produced a non-significant reduction in total lung capacity (TLC) only. Lobectomy (n = 14) reduced forced vital capacity (FVC), TLC, and carbon monoxide transfer factor but exercise capacity was unchanged. Only pneumonectomy (n = 13) reduced exercise capacity by 28% (PVO2 23.9 (1.5) versus 17.2 (1.7) ml/min/kg; difference (95% CI) 6.72 (3.15 to 10.28); p<0.01) and three patients changed from a cardiac limitation to exercise before pneumonectomy to pulmonary limitation afterwards. CONCLUSIONS: Neither thoracotomy alone nor limited lung resection has a significant effect on exercise capacity. Only pneumonectomy is associated with impaired exercise performance, and then perhaps not as much as might be expected.

Exercise Test↗
PubMed1998

Effectiveness of Menuzo's B2 medium with buffalo rat liver cells for development of in vitro matured/in vitro fertilized bovine oocytes.

PURPOSE: The effectiveness of two culture media on the development of bovine embryos in a buffalo rat liver (BRL) coculture system was investigated. METHODS: Bovine oocytes were matured and fertilized in vitro, then cocultured, 25 per well, for 7 days in 500 microliters of modified M199 or modified Menuzo's B2 medium over a BRL cell monolayer at 39 degrees C in an atmosphere of 5% CO2 in air. Medium 199 was modified by the addition of 10% of (v/v) fetal bovine serum (FBS), 9 mg/ml bovine serum albumin, 2 mM glycine, 1 mM alanine, and 0.1 mM nonessential amino acids (NEAA). Menuzo's B2 medium was modified by the addition of 10% (v/v) FBS, 1 mM alanine, and 0.1 mM NEAA. RESULTS: Modified Menuzo's B2 medium improved embryo development to the morula or blastocyst stage compared to modified M199 (121/353, 34.3%, versus 99/362, 27.3%, P < 0.05). CONCLUSIONS: These results suggest that Menuzo's B2 medium with modifications in a BRL coculture system can provide a significant benefit for culture of early bovine embryos over the traditional use of medium 199.

Animals↗
PubMed1997

Functional interrelationships between follicles greater than 4 mm and the follicle-stimulating hormone surge in heifers.

The interrelationships between the FSH surge that initiates a follicular wave and the follicles in the wave were examined in heifers. In experiment 1, > or = 5-mm follicles were ablated 5 days after ovulation and heifers (n = 6/group) received a total dosage of 0, 37.5, 75, or 150 units of porcine FSH. Half of the FSH dosage was administered 24 h after ablation followed by the other half 12 h later. Blood samples were taken after the initial FSH injection for FSH assay, and ovaries were examined daily with ultrasound to monitor follicle growth. There were progressively higher FSH concentrations at the mean peak (8 h after initial injection in all groups) as the dosage increased (interaction of dose and time; p < 0.001). Compared to values in controls, the highest dosage (150 units) approximately doubled the number of 5- and 6-mm follicles; this then progressed into a 4- to 7-fold increase in the number of 7- and 8-mm follicles. In experiment 2, either all (controls; n = 6), two (n = 11), one (n = 6), or zero (n = 6) follicles of the first wave of an estrous cycle were retained and the remaining were ablated upon reaching 5 mm. Scanning and blood sampling were performed every 8 h for 72 h after the initial ablation. Mean FSH concentrations during 0 to 72 h decreased (p < 0.004) as the number of retained follicles increased. In heifers in the one-follicle group, the randomly chosen 5-mm follicle developed the characteristics of a dominant follicle. The following conclusions were made: 1) the number of follicles that advanced into a follicular wave was increased by exaggerating the height of the FSH surge, 2) all > or = 5-mm follicles of a wave contributed to the declining portion of the FSH surge, and 3) any 5-mm follicles at the emergence of a wave were capable of becoming the dominant follicle.

Animals↗
PubMed1995

Nuclear transfer in the bovine using microinjected donor embryos: assessment of development and deoxyribonucleic acid detection frequency.

Bovine embryos that had been microinjected with DNA were examined for their potential use as donor embryos in nuclear transfer. Donor embryos were obtained from oocytes collected by transvaginal oocyte aspiration, matured and fertilized in vitro, microinjected with a murine whey acidic protein-human protein C genomic DNA construct, and cultured in vitro on liver cells of buffalo rat (Rattus norvegicus). Blastomeres from these embryos were transferred into enucleated bovine oocytes received from an abattoir by electrofusion at 40 h postmaturation. Following 7 d of culture, the developmental stage was recorded, and resulting embryos were prepared for analysis by polymerase chain reaction. Embryos that were derived from microinjected donor embryos did not differ from control donor embryos (11 vs. 8.6%) in development to the morula and blastocyst stage. Of the biopsies from 20 microinjected donor embryos, 19 were positive for the injected DNA. Of 37 embryos developing normally, only 12 (32.4%) were positive for the injected DNA. These results indicate that microinjected embryos can be successfully used in a nuclear transfer program to produce additional viable embryos and that these embryos may be reliably screened for the transgene for transfer to recipients.

Animals↗
PubMed1994

Influence of time of gene microinjection on development and DNA detection frequency in bovine embryos.

The effect of DNA microinjection at various times after in vitro insemination on DNA detection and survival rates of bovine embryos was investigated. Oocytes were inseminated 24 h after maturation with frozen/thawed semen prepared with a Percoll separation procedure. At 11, 15 and 19 h after insemination, embryos were centrifuged to visualize pronuclei and microinjected with a murine whey acidic protein-human protein C genomic DNA construct. After culture for 7 days on Buffalo Rat Liver cells, embryos were assessed for stage of development and assayed for the presence of the transgene by polymerase chain reaction. Of zygotes in the 11 h after insemination treatment, 16% (25/152) of non-injected and 7% (11/161) of injected embryos developed to the morula or blastocyst stage. Comparable development of non-injected and injected embryos treated at 15 h after insemination was 15% (23/158) and 4% (6/159) and treated at 19 h after insemination was 14% (23/162) and 1% (1/165), respectively. Development of injected embryos was greater (p < 0.05) when injection was performed at 11 h after insemination compared to 19 h after insemination. Development of non-injected embryos was greater (p < 0.01) than that of injected embryos. There was no difference in transgene detection frequency in embryos of all developmental states between treatments (53% at 11; 50% at 15; 48% at 19 h after insemination). Injected embryos testing positive for the presence of the transgene exhibited increased development over negative embryos (p < 0.01). Greater development efficiencies can be obtained in microinjected bovine embryos when injection is performed early in pronuclear formation.

Animals↗
PubMed1994

Tracheobronchial injury in blunt and penetrating chest trauma.

Ten patients were seen in Northern Syria with tracheobronchial injury from June 1986 to July 1988. Eight were male; and five were children. Blunt trauma was the cause of rupture in five and penetrating trauma in five. Nine patients had associated injuries. In seven, the diagnosis was made within 24 h. The seven patients who had surgery were well at last follow-up, as was a child with a main bronchial tear who was treated conservatively. Two men died without having surgery, one of respiratory failure and sepsis and the other of hemorrhagic shock. The group's mean age was 17.5 years. The average hospital stay was six days (eight for survivors), and the follow-up period was seven months. The clinical presentations and outcome stress the essential role of early chest x-ray and bronchoscopy, as well as a high index of suspicion.

Adolescent↗
PubMed1993

Prophylactic digitalization fails to control dysrhythmia in thoracic esophageal operations.

A prospective, controlled, randomized study of 80 patients undergoing esophageal operations was undertaken, in which one group of patients was given digoxin and the other was not. The incidence of cardiac dysrhythmia was compared in each group. Twenty-six patients underwent operation for benign disease. Equal numbers were digitalized or not and no dysrhythmias occurred. Fifty-four patients underwent operation for malignant disease. Of 26 in the group digitalized, 12 suffered dysrhythmia (46%). Of 28 not digitalized, 9 suffered dysrhythmia (32%). Overall, 39% of patients with malignant disease suffered a dysrhythmia compared with none with benign disease (p < 0.002 by chi 2).

Aged↗
PubMed1993

Diagnostic rigid and flexible oesophagoscopy in carcinoma of the oesophagus: a comparison.

BACKGROUND: Flexible oesophagoscopy is regarded as superior to rigid oesophagoscopy on the basis of perforation rates as an end point. This advantage may be more apparent than real because no comparison has been made in a diagnostic setting in patients with carcinoma of the oesophagus with both perforation rate and diagnostic efficacy as indices. METHODS: A retrospective analysis was carried out on data on 336 diagnostic oesophagoscopies in patients with carcinoma of the oesophagus, comparing rigid with flexible oesophagoscopy. RESULTS: Both rigid and flexible oesophagoscopies were performed without perforation when they were used for diagnosis only. Rigid biopsy achieved a diagnostic success rate of 99.3%, compared with 80.5% for flexible oesophagoscopy. CONCLUSIONS: Diagnostic oesophagoscopy can be achieved without perforation with either instrument, but the chance of diagnosing carcinoma was significantly greater with the rigid instrument.

Biopsy↗
PubMed1993

Congenital oesophageal respiratory tract fistula presenting in adult life.

Congenital oesophageal respiratory tract fistula presenting in adult life is rare. A tracheo-oesophageal and a broncho-oesophageal fistula presenting in a 22 year old female and 68 year male, respectively, are described. In both, symptoms of chronic recurrent pulmonary suppuration were initially attributed to alternative aetiologies, resulting in diagnostic delay and inappropriate management. Correct diagnosis was established by flexible bronchoscopy and oesophageal contrast studies. Surgical division of fistulae resulted in complete symptom resolution.

Adult↗
PubMed1992

The role of rigid oesophagoscopy in oesophageal carcinoma.

The efficacy and safety of rigid oesophagoscopy in diagnostic and therapeutic settings in a consecutive series of 404 patients with oesophageal carcinoma were studied and compared to that for flexible oesophagoscopy in the same group. In addition, we examined the same parameters in a smaller group who had undergone radiotherapy with subsequent malignant stricturing. We performed 328 rigid procedures and 118 flexible procedures in a single regional surgical referral unit over a 7 year period. The combined perforation rate was 1.3%, with an overall mortality of 1% from 446 procedures. We conclude that rigid oesophagoscopy in the presence of carcinoma retains an important diagnostic and therapeutic role which can be achieved with low incidence of perforation in high-risk patients.

Dilatation↗
PubMed1992

Prophylactic digitalisation in pulmonary surgery.

BACKGROUND: Prophylactic digoxin is widely used in patients undergoing pulmonary surgery to prevent or control cardiac arrhythmias, but whether it is helpful or not is uncertain. METHODS: An open, controlled randomised prospective clinical study of 111 patients was undertaken to compare the incidence of cardiac arrhythmias in the 58 patients who received preoperative digoxin and the 53 who did not. RESULTS: Cardiac arrhythmia occurred in half (29/58) of those given prophylactic digoxin and in 36% (19/53) of those who were not. The overall incidence of arrhythmia was 43%, with no statistically significant difference between the groups. CONCLUSION: Cardiac arrhythmias remain an important complication of pulmonary surgery and the incidence is not reduced by prophylactic digoxin.

Aged↗