The use of catheter-tipped pressure transducers for chronic measurement of genital tract pressures in the ewe. II. Effects of oxytocin and prostaglandin F(2)alpha

Chronic catheterisation of the uterus, ampulla, and abdomen was performed in five ewes using solid-state, catheter-tipped pressure transducers. The catheters remained in place for up to 129 d, allowing in vivo studies of the effects of oxytocin and prostaglandin F(2)alpha (PGF(2)alpha). These agents did not produce any measurable increase in abdominal pressure. Intravenous (i.v.) oxytocin elicited a rapid increase in work done by both the uterus and ampulla. Intramuscular (i.m.) PGF(2)alpha produced a delayed uterine response but little change in the ampulla; i.v. PGF(2)alpha produced a rapid response at both sites. Low plasma progesterone concentrations (< 0.5 ng/ml) were associated with a greater uterine and ampullary response to oxytocin and with an enhanced uterine response to PGF(2)alpha. However, the uterine tube response to intravenous PGF(2)alpha was greatest when plasma progesterone concentrations were high.     

Genital tract pressures in mares. I. Normal pressures and the effect of physiological events

A computerised system involving electronic catheter-tipped transducers was used to measure pressures developed within the vagina and uterus of mares. Larger mares tended to have lower intravaginal pressure than ponies. Insertion of an arm into the vagina to place the catheters caused a rise in intravaginal pressure. Pressure in the uterus was usually higher than that in the vagina. Both vaginal and uterine pressures were increased by urination, snorting, whinnying, stretching and respiration - the latter effect was most noticeable in larger mares. Vaginal pressure was also influenced by peristalsis in the rectum, defaecation, the passage of flatus and the stance of the mare.     

Development of a noninvasive technique for the measurement of intracranial pressure.

Intracranial pressure (ICP) dynamics are important for understanding adjustments to altered gravity. Previous flight observations document significant facial edema during exposure to microgravity, which suggests that ICP is elevated during microgravity. However, there are no experimental results obtained during space flight, primarily due to the invasiveness of currently available techniques. We have developed and refined a noninvasive technique to measure intracranial pressure noninvasively. The technique is based upon detecting skull movements of a few micrometers in association with altered intracranial pressure. We reported that the PPLL technique has enough sensitivity to detect changes in cranial distance associated with the pulsation of ICP in cadavera. In normal operations, however, we place a transducer on the scalp. Thus, we cannot rule out the possibility that the PPLL technique picks up cutaneous pulsation. The purpose of the present study was therefore to show that the PPLL technique has enough sensitivity to detect changes in cranial distance associated with cardiac cycles in vivo.     

Effects of progesterone and oestradiol on RNA and protein metabolism in the genital tract and on survival of embryos in the ovariectomized ewe.

The hormonal regulation of metabolism in the genital tract and the development of embryos during early pregnancy in the ewe have been examined. Ovariectomized ewes received injections of maintenance progesterone, oestrous oestradiol and priming progesterone according to schedules designed to simulate endogenous ovarian secretion during early pregnancy, around the time of oestrus and during the luteal phase of the oestrous cycle immediately preceding oestrus. The survival and development of embryos was dependent upon the dose of maintenaince progesterone and the duration of treatment at the time of transfer, but changes in progesterone dose did not change endometrial protein or RNA metabolism on particular days. Both priming progesterone and oestrous oestradiol were required for normal embryo development. Priming progesterone and oestrous oestradiol each increased endometrial RNA/DNA ratios during early pregnancy. There were no interactions between priming progesterone and oestrous oestradiol, their effects being simply additive. Neither maintenance nor priming progesterone had any effect on protein and RNA metabolism in the oviduct. It is suggested that in the intact ewe oestrogen secreted at oestrus and progesterone secreted prior to oestrus play important roles in the establishment of a uterine environment suitable for the subsequent normal development of embryos.     

The biology and significance of human papillomavirus infections in the genital tract.

A variety of human papillomavirus (HPV) types infect the anogenital mucosa, giving rise to lesions that differ in clinical appearance, histology, and risk of malignant progression. Certain high-risk types (HPVs 16, 18, 31, 33, 35 and 39) have a strong association with high-grade epithelial neoplasia and invasive carcinomas of the anogenital tract. Cancer appears to have a multifactorial etiology, and HPV infection alone is probably insufficient for malignant transformation. The consistent association between HPV infection and anogenital cancers emphasizes, however, that the sexually transmitted papillomaviruses may have a necessary role in carcinogenesis. Hence, there is a prospect that vaccination programs may one day allow public health control of HPV infection, thereby eliminating an important risk factor.     

The effect of the stage of the oestrous cycle and exogenous sex steroids on the transport of starch grains through the genital tract of the ewe, a preliminary study

The starch grain test was studied in two ewes to determine the effect of the stage of the oestrous cycle on their transport through the Fallopian tubes. There was very little difference when the test was performed at oestrus or day 10 of the oestrous cycle. Bilateral ovariectomy had very little effect on the transport of starch grains. When progesterone in oil was administered by intramuscular injection to a bilaterally ovariectomised ewe and an intact ewe there was a marked increase in the number of grains which were recovered. Oestradiol benzoate in oil delayed the recovery of grains and reduced their numbers.     

The use of information technology in improving medical performance. Part I. Information systems for medical transactions

Investment in medical information technologies reached $15 billion in 1996. However, these technologies have not had the wide impact predicted in streamlining bureaucracy, improving communications, and raising the effectiveness of care. In this series, we identify how such technologies are being used to improve quality and performance, the future directions for advancement, and the policy and research developments required to maximize public benefit from these technologies. Each of these articles focuses on a different type of information technology: (1) information systems to manage medical transactions; (2) physician-support technologies to improve medical practice; and (3) patient-focused technologies designed to change how people manage their own care. This first article of a 3-part series examines the successes of and opportunities for using advanced information systems that track and manage medical transactions for large populations to improve performance. Examples of such systems include: HEDIS, which gathers standardized data from health plans on quality of care; the USQA Health Services Research Program, which tracks treatment patterns and outcomes for 14 million insurance members; Ford's program to collect medical data for over 600,000 employees; and Harvard Pilgrim Health Care's system of computerized laboratory, pharmacy, ambulatory, and hospital admission records for its 1.5 million members. Data from these systems have led to modest improvements in knowledge and practice patterns for some diseases. Significant barriers are slowing efforts to add outcomes data to these databases and broaden the databases to cover larger populations. Nonetheless, existing data in currently evolving systems could be used to greater benefit in tracking public health and in identifying more effective treatments and causes of diseases.     

The use of high pressure liquid chromatography (HPLC) for the separation of radiolabeled arachidonic acid and its metabolities produced by thrombin-treated human platelets. I. The validation of the technique

We have developed a technique for the rapid separation and quantitative collection of thromboxane B2 (TXB2), PGE2, PGD2, PGF2 alpha, 12-hydroxy-5,8,10 heptadecatrienoic acid (HHT), 12-L-hydroxy-5,8,10,14 eicosatetraenoic acid (HETE), and arachidonic acid released from thrombin treated human platelets. Platelets were pre-labeled with 3H-arachidonic acid and then isolated by gel filtration. They were then exposed to thrombin for various intervals and separated by centrifugation. Aliquots of the cell-free medium were applied directly to a high pressure liquid chromatograph containing a fatty acid column as the stationary phase. A quarternary solvent system containing tetrahydrofuran (THF), acetonitrile (CH3CN), water and acetic acid (HOAC) resolved and eluted the arachidonic acid metabolites within 30 minutes. Since no sample preparation is required and since the solvent system does not quench the counting efficiency of a standard liquid scintillation fluor the technique permits rapid separation and quantitation of radiolabeled arachidonic acid and its metabolites.