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Biomedical subjects

J H Payne

Publications and source records attributed to J H Payne.

At least 19 recordsLinked to original sources
PubMed1998

Role of early luteal phase progesterone in control of the timing of the luteolytic signal in cows.

The effects of the pattern and concentration of early luteal phase progesterone on subsequent prostaglandin F2 alpha release in response to exogenous oxytocin was investigated during simulated luteal phases in ovariectomized cows treated with progesterone and oestradiol in patterns designed to simulate the range of luteal phase concentrations that occur naturally. In the first experiment, three groups of four cows received different concentrations of early luteal phase progesterone to determine the effective concentration in terms of cycle control. The results show that a plasma progesterone concentration early in the luteal phase as low as 0.6 ng ml-1 was sufficient to affect the timing of the subsequent luteolytic signal. In the second experiment, an early (day 1), a normal (day 4) or a late (day 7) postovulatory increase in progesterone was recreated in three groups of four cows. Responsiveness to oxytocin in the early progesterone group developed 3 days earlier than in the normal progesterone group, demonstrating the ability of early progesterone to advance the luteolytic signal. However, in the late progesterone group, there was no delay in the development of responsiveness to oxytocin compared with the normal progesterone group, demonstrating that the luteolytic signal is programmed to occur by a given time, irrespective of the early progesterone pattern. This demonstrates that a factor other than the timing of the early luteal phase progesterone increase ultimately must control the timing of luteolysis in cows.

Analysis of Variance↗
PubMed1998

Laparoscopic staging of malignant disease.

The earliest applications of laparoscopy were for diagnostic procedures. The goal was to make a diagnosis while sparing the patient a major, and often futile, operation. However, the view was limited and it was not possible to palpate organs or masses. The recent development of advanced laparoscopic techniques and ultrasound have improved our view and restored our "sense of touch". These innovations bring the goal of minimally invasive diagnosis and staging closer to reality. This paper reviews the current literature on the laparoscopic staging of cancer with an emphasis on patient selection, diagnostic accuracy, and the reduction in morbidity which can be achieved.

Gastrointestinal Neoplasms↗
PubMed1998

Advanced laparoscopy: "the next generation". The adrenal, kidney, spleen, pancreas, and liver.

Following the rapid acceptance of laparoscopic cholecystectomy, a few adventurous surgeons "dared to boldly go where no one had gone before." They sought to achieve the same reduction in morbidity while accomplishing the same surgical goals. This paper will briefly review the current status of minimal access surgery for the solid organs of the abdomen. It will focus on the indications, risks, limitations, and on the balance between the trauma of access and the trauma of the procedure itself. As new techniques and equipment emerge and experience and data are accumulated, this balance may shift. Some of these procedures are in their infancy while others are rapidly becoming the new "Gold Standard".

Adrenalectomy↗
PubMed1997

Telementoring. A practical option in surgical training.

BACKGROUND: Telemedicine offers significant advantages in bringing consulting support to distant colleagues. There is a shortage of surgeons trained in performing advanced laparoscopic operations. AIM: Our aim was to evaluate the role of telementoring in the training of advanced laparoscopic surgical procedures. METHODS: Student surgeons received a uniform training format to enhance their laparoscopic skills and intracorporeal suturing techniques and specific procedural training in laparoscopic colonic resections and Nissen fundoplication. Subsequently, operating rooms were equipped with three cameras. Telestrator (teleguidance device), instant replay (to critique errors), and CD-ROM programs (to provide information of reference) were used as intraoperative educational assistance tools. In phase I, four colonic resections were performed with the mentor in the operating room (group A) and four colonic resections were performed with the mentor on the hospital grounds, but not in the operating room (group B). The voice and video signals were received at the mentor's location, using coaxial cable. In phase II, two Nissen fundoplications were performed with the mentors in the operating room (group C) and two Nissen fundoplications were performed with the mentors positioned five miles away from the operating room (group D), using currently existing land lines at the T-1 level. RESULTS: There were no differences in the performances of the surgeons and outcome of the operations between groups A & B and C & D. It was possible to tackle the intraoperative problems effectively. CONCLUSIONS: The telementoring concept is potentially a safe and cost-effective option for advanced training in laparoscopic operations. Further investigation is necessary before routine transcontinental patient applications are attempted.

Fundoplication↗
PubMed1996

The effect of oxytocin and oestradiol on the action of conceptus secretory protein in progesterone-treated ovariectomized ewes.

In intact cyclic ewes intrauterine infusion of conceptus secretory proteins results in the suppression of both endometrial oxytocin receptor concentrations and oxytocin-induced prostaglandin F2 alpha release. However, similar infusion in progesterone-treated ovariectomized ewes, while suppressing endometrial oxytocin receptors, does not fully inhibit oxytocin-induced prostaglandin F2 alpha release. To examine whether this anomaly resulted from an inadequate simulation of the luteal phase in the ovariectomized ewe treated with progesterone alone, the effects of additional treatment with two other ovarian hormones, oestradiol-17 beta and oxytocin, was investigated. Rather than permitting conceptus secretory protein to successfully inhibit oxytocin-induced prostaglandin F2 alpha release, treatment with oestradiol-17 beta in addition to progesterone actually resulted in an advancement in the timing of release. However, treatment with oxytocin, alone or in combination with oestradiol, permitted the full inhibition of oxytocin-induced prostaglandin F2 alpha release. To confirm that this effect did not result from the action of oxytocin alone, independently of the action of conceptus secretory protein, a second experiment was undertaken using a similar protocol but without the infusion of conceptus secretory protein. In this situation, oxytocin-induced prostaglandin F2 alpha release was only partially inhibited suggesting that both luteal oxytocin and conceptus secretory proteins are necessary to facilitate the full inhibition of luteolysis during early pregnancy in the ewe.

Animals↗
PubMed1996

Regulation of oxytocin, oestradiol and progesterone receptor concentrations in different uterine regions by oestradiol, progesterone and oxytocin in ovariectomized ewes.

The regulation of oxytocin, oestradiol and progesterone receptors in different uterine cell types was studied in ovariectomized ewes. Animals were pretreated with a progestogen sponge for 10 days followed by 2 days of high-dose oestradiol to simulate oestrus. They then received either low-dose oestradiol (Group E), low-dose oestradiol plus progesterone (Group P) or low-dose oestradiol, progesterone and oxytocin (via osmotic minipump; Group OT). Animals (three to six per time-point) were killed following ovariectomy (Group OVX), at oestrus (Group O) or following 8, 10, 12 or 14 days of E, P or OT treatment. In a final group, oxytocin was withdrawn on day 12 and ewes were killed on day 14 (Group OTW). Oxytocin receptor concentrations and localization in the endometrium and myometrium were measured by radioreceptor assay, in situ hybridization and autoradiography with the iodinated oxytocin receptor antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin. Oestradiol and progesterone receptors were localized by immunocytochemistry. Oxytocin receptors were present in the luminal epithelium and superficial glands of ovariectomized ewes. In Group O, endometrial oxytocin receptor concentrations were high (1346 +/- 379 fmol [3H]oxytocin bound mg protein-1) and receptors were also located in the deep glands and caruncular stroma in a pattern resembling that found at natural oestrus. Continuing low-dose oestradiol was unable to sustain high endometrial oxytocin receptor concentrations with values decreasing significantly to 140 +/- 20 fmol mg protein-1 (P < 0.01), localized to the luminal epithelium and caruncular stroma but not the glands. Progesterone treatment initially abolished all oxytocin receptors with none present on days 8 or 10. They reappeared in the luminal epithelium only between days 12 and 14 to give an overall concentration of 306 +/- 50 fmol mg protein-1. Oxytocin treatment caused a small increase in oxytocin receptor concentration in the luminal epithelium on days 8 and 10 (20 +/- 4 in Group P and 107 +/- 35 fmol mg protein-1 in Group OT, P < 0.01) but the rise on day 14 was not affected (267 +/- 82 in Group OT and 411 +/- 120 fmol mg protein-1 in Group OTW). In contrast, oestradiol treatment was able to sustain myometrial oxytocin receptors (635 +/- 277 fmol mg protein-1 in Group O and 255 +/- 36 in Group E) and there was no increase over time in Groups P, OT and OTW with values of 61 +/- 18, 88 +/- 53 and 114 +/- 76 fmol mg protein-1 respectively (combined values for days 8-14). Oestradiol receptor concentrations were high in all uterine regions in Group O. This pattern and concentration was maintained in Group E. In all progesterone-treated ewes, oestradiol receptor concentrations were lower in all regions at all time-points. The only time-related change occurred in the luminal epithelium in which oestradiol receptors were undetectable on day 8 but developed by day 10 of progesterone treatment. Progesterone receptors were present at moderate concentrations in the deep glands, caruncular stroma, deep stroma and myometrium in Group O. Oestradiol increased progesterone receptors in the luminal epithelium, superficial glands, deep stroma and myometrium. Progesterone caused the loss of its own receptor from the luminal epithelium and superficial glands and decreased its receptor concentration in the deep stroma and myometrium at all time-points. There was a time-related loss of progesterone receptors from the deep glands of progesterone-treated ewes between days 8 and 14. These results show differences in the regulation of receptors between uterine regions. In particular loss of the negative inhibition by progesterone on the oxytocin receptor by day 14 occurred only in the luminal epithelium, but is unlikely to be a direct effect of progesterone as no progesterone receptors were present on luminal epithelial cells between days 8 and 14.

Animals↗
PubMed1995

Local action of trophoblast interferons in suppression of the development of oxytocin and oestradiol receptors in ovine endometrium.

Luteolysis in sheep is associated with uterine secretion of pulses of prostaglandin F2 alpha (PGF2 alpha) due to the action of luteal oxytocin on endometrial oxytocin receptors. For pregnancy to become established inhibition of oxytocin receptors is important as an antiluteolytic mechanism. The maternal recognition of pregnancy in cattle and sheep involves production, by the trophoblast, of a type 1 interferon (IFN-tau) that suppresses uterine development of oxytocin receptors and the generation of luteolytic episodes of PGF2 alpha. The action of IFN-tau in surgically prepared unilaterally pregnant ewes was investigated. Finn-Dorset ewes were anaesthetized on day 6 or 7 of the oestrous cycle and one uterine horn was surgically isolated at the uterine bifurcation from the body of the uterus. Ewes were mated at the subsequent oestrus either by a fertile or by a vasectomized ram and killed on day 13 or 16 after mating. On day 16, in the non-pregnant ewes, there was no measurable uterine IFN-tau but there were high concentrations of oxytocin receptors in both horns. In the pregnant ewes on day 16 after mating, the oxytocin receptor concentration was 45 +/- 11 fmol mg-1 protein in the pregnant horn and 585 +/- 131 fmol mg-1 in the non-pregnant horn. Antiviral activity was 5.8 x 10(7) +/- 5.2 x 10(7) U ml-1 in the pregnant horn and 2.9 x 10(3) +/- 1.2 x 10(3) U ml-1 in the non-pregnant horn. Thus, 16 days after mating, the pregnant horn exhibited high antiviral activity but oxytocin receptors were suppressed, while in the same endocrine environment (characteristic of pregnancy) there were low IFN-tau and high oxytocin receptor concentrations in the isolated horn equivalent to those expected at the onset of luteolysis. In situ hybridization to ovine mRNA encoding the oxytocin receptor and autoradiographic studies using the 125I-labelled oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin both showed that the large amount of oxytocin receptor message and binding sites in the endometrium of the isolated horn were localized in the luminal epithelium. Immunocytochemical studies showed that there was a suppression of oestradiol receptors in the pregnant horn but high concentrations equivalent to those at oestrus were present in the isolated horn. The content of progesterone receptors was low in the stromal tissue only in both horns, a pattern of localization similar to that seen in the late luteal phase and in early pregnancy.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Laparoscopic or open inguinal herniorrhaphy? A randomized prospective trial.

OBJECTIVE: To determine whether transabdominal preperitoneal laparoscopic hernia repair can equal or surpass an established open method at an acceptable cost. DESIGN: A randomized, prospective comparison with a follow-up of 7 to 18 months (median, 10 months; planned, 5 years). SETTING: Health maintenance organization hospital. PATIENTS: One hundred patients between 20 and 70 years of age were randomized. No patient withdrew from the study after randomization. INTERVENTIONS: Transabdominal preperitoneal laparoscopic and open tension-free repairs using a polypropylene mesh. MAIN OUTCOME MEASURES: Operative and discharge times, costs, recovery, and morbidity. "Return to work" was supplemented by a performance assessment using a panel of exercises. RESULTS: Operative and hospitalization times were not significantly different between the two types of repair. Patients with laparoscopic unilateral repairs returned to work faster (9 vs 17 days). At 1 week postoperatively, performance of straight-leg raises correlated well with time to return to work for patients with strenuous jobs. The laparoscopic repair was more expensive than the open approach ($3093 vs $2494). CONCLUSIONS: Laparoscopic transabdominal preperitoneal hernia repair can be accomplished with operative and hospitalization times and a short-term recurrence rate similar to those of an established open technique. Perioperative exercise testing may be an important adjunct to return to work in the comparison of methods.

Adult↗
PubMed1994

Ultrasonic dissection.

Following its development for cataract surgery, and gaining widespread use in neurosurgery and liver resection, ultrasonic dissection has been adapted for laparoscopic use. The turbulence, heat, and pressure generated by imploding bubbles disrupts tissues high in water content. This phenomenon is called cavitation and is the principal means by which ultrasonic dissection is accomplished. A randomized, prospective trial demonstrated the utility of the device for laparoscopic cholecystectomy. It was particularly effective in the presence of acute periportal inflammation or fat. Additional experience with a wide range of laparoscopic procedures is being accumulated by several investigators around the world. The laparoscopic use of ultrasonic dissection will be most valuable whenever selective, precise, and, therefore, safe dissection is desired.

Cholecystectomy, Laparoscopic↗
PubMed1994

The direct influence of the embryo on uterine PGF2 alpha and PGE2 production in sheep.

In unilateral pregnant ewes, obtained by surgically transecting one uterine horn to isolate it from the rest of the pregnant uterus, the isolated horn develops endometrial oxytocin receptors by day 16 despite being in a hormonal environment equivalent of that of a pregnant ewe. This study examines uterine prostaglandin production in these animals. On day 16 of pregnancy, ewes were anaesthetized and a uterine vein draining each horn and the jugular vein cannulated. Venous blood samples were taken at 10 min intervals for 1 h before and 1 h after an i.v. injection of oxytocin (1 microgram). Uterine vein samples were assayed for PGF2 alpha and PGE2 and jugular blood samples assayed for 13,14-dihydro,15-keto-PGF2 alpha. All ewes showed high plasma concentrations of 13,14-dihydro,15-keto-PGF2 alpha after the oxytocin injection. PGF2 alpha increased in the uterine vein draining the nonpregnant transected horn of a unilaterally pregnant ewe following oxytocin treatment, whereas there was no increase in concentration in plasma draining the pregnant horn. Basal plasma PGF2 alpha concentrations from the uterine vein draining the pregnant horn were significantly higher than concentrations obtained from the uterine vein of the transected horn while PGE2 concentrations did not vary between the two horns. After oxytocin injection, there was a significant increase in plasma PGE2 concentration in venous blood collected from both sides.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Community care.

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Aged↗
PubMed1993

Pulsatile release of oxytocin after suppression of prostaglandin synthesis in hysterectomised ewes.

On days 13 and 14 after oestrus (day 0) oxytocin and 13,14-dihydro-15-keto-prostaglandin (PG)F2 alpha (PGFM) concentrations were measured in jugular plasma of hysterectomised sheep with or without systemic treatment with the PG cyclo-oxygenase inhibitor indomethacin (4 mg kg-1 three times a day on days 12, 13 and 14 subcutaneously. Pulsatile increases of oxytocin were observed in both untreated and treated sheep with mean (+/- SD) peak heights of 18.4 +/- 9.6 pg ml-1 (n = 11) and 23.5 +/- 9.4 pg ml-1 (n = 8), respectively; these means were not significantly different. Plasma concentrations of PGFM remained consistently low in both groups (under 100 pg ml-1) with no significant peaks observed. The data suggest that PGF2 alpha may not be the only stimulus for the release of luteal oxytocin, or that there may be a contribution by the posterior pituitary to oxytocin secretion during the luteal phase of the ovine oestrous cycle.

Activity Cycles↗
PubMed1992

The ultrasonic dissector facilitates laparoscopic cholecystectomy.

The ultrasonic dissector disrupts tissues in proportion to their fluid content by ultrasonically induced cavitational forces. Since sturdy tissues are spared, the instrument tends to follow tissue planes and to dissect fat and other soft tissues selectively. We performed a prospective, randomized, controlled trial in 73 patients comparing the safety and efficacy of a prototype ultrasonic dissector with that of electrosurgery and laser during laparoscopic cholecystectomy. Randomization was as follows: ultrasonic dissector, 37 patients; electrosurgery, 21 patients; and laser, 15 patients. The results were not different with respect to patient characteristics, amount of blood loss, technical difficulties, length of hospital stay, or return to work. Subjectively, the ultrasonic dissector was thought to be of special value in isolating the hilar structures, particularly when they were edematous or embedded in fat. The ultrasonic dissector disintegrated the fat, which was rapidly cleared up the suction channel, allowing the cystic duct and artery to be bared with less risk of injury. We concluded that the ultrasonic dissector has unique attributes that contribute to the ease and safety of laparoscopic cholecystectomy.

Adolescent↗
PubMed1992

Direct stimulation of bovine ovarian progesterone secretion by low concentrations of alpha-interferon.

The ruminant conceptus secretes proteins during early pregnancy which maintain the corpus luteum. These trophoblast proteins are related to the alpha II-interferons and prevent luteolysis indirectly by disrupting the secretion of endometrial prostaglandin. Although trophoblast interferons appear to be largely confined to the uterine lumen, it remains possible that they also act peripherally. This report describes in vitro studies which suggest that interferon may influence hormone secretion by the ovary directly. The study employed i) a well defined serum-free culture model in which bovine granulosa cells secrete the luteal hormones progesterone and oxytocin, and ii) serum-free and serum-supplemented cultures of cells from early CL. Dose-response experiments were performed using bovine recombinant alpha-interferon (brIFN). Progesterone and oxytocin secretions were measured over 4-5 days of culture and DNA content was also determined. Low concentrations of brIFN (10(-15) mol/l to 10(-11) mol/l) stimulated progesterone secretion by granulosa cells by up to three fold, without significantly affecting oxytocin concentrations or culture DNA content. Concentrations of 10(-10) mol/l to 10(-1) mol/l suppressed progesterone secretion in a log dose-related manner (r = 0.97) with evidence of toxicity (lower oxytocin concentrations and significantly reduced DNA compared with controls). Progesterone secretion by luteal cells in serum-free culture was stimulated in the presence of 10(-15) mol/l brIFN, whilst high concentrations again caused inhibition. The data show that ovarian cells can respond directly to low concentrations of interferon-like proteins.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Role of the oxytocin receptor in the choice between cyclicity and gestation in ruminants.

The endometrial oxytocin receptor occupies a central point in the choice between luteolysis and pregnancy in ruminants. Receptor expression determines the time at which luteolysis occurs in nonpregnant animals, and thereby determines the duration of the oestrous cycle. Inhibition of receptor expression by trophoblast interferon (IFN) blocks the process of luteal regression and leads to continued progesterone secretion and the successful growth of the conceptus. Trophoblast IFN is probably required from the time of normal luteolysis during the cycle until luteal oxytocin concentrations of pregnancy decline, thus removing the stimulatory mechanism for the release of the episodes of prostaglandin F2 alpha required for luteolysis.

Animals↗