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Biomedical subjects

D L Watson

Publications and source records attributed to D L Watson.

At least 55 records · Page 3Linked to original sources
PubMed1990

The contribution of symptomatology and/or uterine activity to the incidence of unscheduled visits.

Home uterine activity monitoring and perinatal nursing support have been shown to be associated with a decrease in preterm births with no increase in the number of unscheduled patient visits. This prospective, randomized multicenter study compared the frequency of unscheduled visits in patients receiving home uterine activity monitoring and perinatal nursing support with that of patients receiving education regarding the detection and reporting of preterm labor symptomatology. The contribution of patient-reported signs and symptoms versus objective uterine activity data to unscheduled visits is assessed. The overall frequency of unscheduled visits was similar in both groups. In the home uterine activity monitoring and perinatal nursing support group, the contributions of uterine activity versus signs and symptoms to the diagnosis of preterm labor were equal, with 36% of patients diagnosed with preterm labor sent to the physician for increased uterine activity and 36% for signs and symptoms. The sensitivity for the group receiving monitoring and nursing support in detecting preterm labor was 93%. The majority of false-positive visits were associated with patient symptoms. These data show that this combination service does not lead to a clinically significant increase in unscheduled visits. Further, the visits resulting from the combination service provide a sensitive predictive method to aid physicians in detecting early labor.

Clinical Trials as Topic↗
PubMed1990

Relationship of uterine contractility to preterm labor.

An increased uterine contraction rate is associated with preterm labor. The contraction rate in individual patients, however, has not been evaluated critically as to its predictive value in forecasting early labor. In this randomized multicenter study, 105 patients at high risk for preterm delivery monitored their contraction rate at home on a daily basis. An analysis was conducted to determine the association of at least four contractions per hour on a routine strip followed by at least four contractions per hour on a repeat tracing with subsequent preterm labor. Using this threshold, 70% of the patients were correctly classified. This contraction rate resulted in a sensitivity of 57%, a specificity of 80%, a positive predictive value of 72%, and a negative predictive value of 68%. A threshold rate of at least four contractions per hour on a remonitor strip identifies a patient at increased risk for preterm labor (P = .003).

Cardiotocography↗
PubMed1990

Home uterine activity monitoring is associated with a reduction in preterm birth.

The value of home uterine activity monitoring plus perinatal nursing support in the prevention of preterm birth among high-risk patients has been demonstrated by several studies. Other reports with less stringent guidelines and less intensive nursing contact have questioned the contribution of home uterine activity monitoring and perinatal nursing support to a preterm birth prevention program. In this large, prospective, randomized multicenter study, patients were assigned to receive either daily monitoring and nursing contact or a preterm birth prevention program including intensive education and more frequent prenatal visits. Among the monitored patients, there was a significant increase in early detection of preterm labor (2 cm or less), successful tocolysis, and prolongation of pregnancy to term. Thirty-one percent of these diagnoses of preterm labor resulted from evaluation of increased uterine activity without associated patient-perceived symptoms. We conclude that a program of daily uterine activity monitoring and perinatal nursing support results in earlier diagnosis of preterm labor and subsequently more effective tocolysis.

Cardiotocography↗
PubMed1990

Preventing preterm birth in twin gestation: home uterine activity monitoring and perinatal nursing support.

In this investigation, 45 women with twin gestations in four centers were randomly assigned to either daily home uterine activity monitoring and perinatal nursing support (19) or an education group (26). Patients in the home uterine activity monitoring and perinatal nursing support group monitored uterine activity twice daily, transmitted the data each day, and had 24 hour-a-day access to nursing support. Education patients were counseled regarding the common signs and symptoms of preterm labor. Both groups had scheduled prenatal visits at least every 2 weeks. Sixteen (62%) of the education group and 14 (74%) of the home uterine activity monitoring and perinatal nursing support group developed preterm labor, values that were not significantly different. Of the monitored group who experienced preterm labor, all 14 were dilated 3 cm or less at diagnosis of the first preterm labor, compared with ten of 16 in the education group (P = .01; one-tailed Fisher test). The mean cervical dilatation at the first preterm labor episode in the group receiving daily monitoring and contact (1.6 cm) was significantly less (P = .01) than that in the education group (2.9 cm). Thus, fewer preterm births were recorded in the home uterine activity monitoring and perinatal nursing support group and significantly fewer patients delivered because of failed tocolysis (P = .03).

Adult↗
PubMed1990

Management of preterm labor patients at home: does daily uterine activity monitoring and nursing support make a difference?

Daily home uterine activity monitoring and perinatal nursing support were compared with standard care in managing patients with recurrent preterm labor during the current pregnancy in an effort to reduce preterm birth. Sixty-seven successfully treated preterm labor patients were randomly assigned in this multicenter study to daily home uterine activity monitoring and perinatal nursing support or to a standard-care group. Recurrent preterm labor occurred in 15 (45%) of monitored patients and 19 (56%) of standard-care patients. The risk of preterm birth (before 37 weeks) for patients with recurrent preterm labor was significantly reduced (P = .025) in the monitored group (seven, or 47%) compared with the standard-care group (16, or 84%). The relative risk of delivering because of failed tocolysis was 2.8 for the standard-care group versus the monitored group. There were no patients in the monitored group who delivered at the first recurrence of preterm labor for failed tocolysis. The data suggest that home uterine activity monitoring and perinatal nursing support are helpful in achieving term birth through earlier detection and treatment of recurrent preterm labor.

Adult↗
PubMed1989

Calcium channel antagonist receptors in cerebral cortex from alcoholic patients.

Exposure to ethanol for days to weeks enhances the expression of voltage-dependent Ca2+ channels in the brains of experimental animals and in cultured neural cell lines. To determine if similar changes occur in the brains of alcoholic patients, we measured the binding of (+)-[3H]PN 200-110 to cerebral cortex samples obtained at autopsy from alcoholic and non-alcoholic patients. No difference in (+)-[3H]PN 200-110 binding was observed, suggesting that ethanol-induced changes in Ca2+ channel expression are more likely to be related to acute withdrawal than to chronic ethanol exposure alone.

Aged↗
PubMed1989

Inflammatory response and antigen localization following immunization with influenza virus ISCOMs.

The inflammatory response, antigen retention, and antigen localization was studied in mice after immunization with influenza virus glycoproteins presented in two physically defined forms--micelles and ISCOMS (immunostimulating complexes). Two hours after intraperitoneal injection, the proportion of polymorphonuclear leukocytes (PMNs) in peritoneal lavage cells increased from less than 1% to 82% in ISCOM-treated mice and from less than 1% to 41% of the total cell count in micelle-treated mice. For both treatment groups, the proportion of PMNs returned to around zero 24 h postimmunization. Total recovery of radioactive antigen was significantly greater (P less than 0.05) in ISCOM-treated than in micelle-treated mice at one, two, and eight days postinjection. At all times tested, animals given ISCOMs had significantly more radioactive antigen in their spleens than animals given micelles. By electron microscopy ISCOMs were found to attach externally to the plasma membrane or within phagosomes of macrophages in close association with the membranes.

Animals↗
PubMed1989

Significance of Freund's adjuvant/antigen injection granuloma in the maintenance of serum antibody response.

An experimental system involving injections of ovalbumin (OVA) and ferritin (FER) in Freund's incomplete adjuvant (FIA) into the right and left flank skin folds of sheep was used to study the influence of the FIA/antigen depot and the draining lymph node in maintaining an antibody response. Excision of the injection granuloma and draining lymph node from one side 2-3 months after injections resulted in a profound decrease in serum antibody titres. This response was observed in all eight sheep in the experimental group. In five of eight animals in another experiment, excision of the injection sites had no appreciable effect on antigen-specific antibody titres when compared with antibody specific for antigen on the intact side of the sheep. In the remaining three animals, excision of the injection site did cause some fall in titre. Radiotracer studies revealed that about one-third of the original [125I]OVA/FIA injected was present in the granuloma 20 weeks after injection. Lymphatic cannulation approaches were used to study the responsiveness of the lymph node draining an FIA/antigen granuloma established 12 weeks earlier and showed that increments of 1-2 mg OVA in saline administered adjacent to the granuloma at 6-7 day intervals gave rise to strong anti-OVA containing cell (AOCC) responses in lymph. There were 2-6-fold increases in serum antibody titre in response to 3-5 doses of OVA or FER (1-2 mg) in saline injected adjacent to the FIA/antigen injection site (which had been administered 14-16 weeks previously). It is concluded that the release rate of antigen from a FIA/antigen depot is insufficient to sustain maximal antibody levels in blood serum.

Animals↗
PubMed1989

Comparative effects of chronic exposure to ethanol and calcium channel antagonists on calcium channel antagonist receptors in cultured neural (PC12) cells.

Treatment with 200 mM ethanol for 6 days increased binding of the Ca2+ channel antagonist, (+)-[3H]PN 200-110, to intact PC12 cells in culture. Enhancement of binding by ethanol was due to an increase in binding site number without appreciable change in binding affinity. Long-term exposure to Ca2+ channel antagonist drugs (nifedipine, verapamil, or diltiazem), which, like ethanol, acutely inhibit Ca2+ flux, failed to alter (+)-[3H]PN 200-110 binding to PC12 membranes. Cotreatment of ethanol-containing cultures with the Ca2+ channel agonist, Bay K 8644, did not attenuate the response to ethanol; instead, chronic exposure to Bay K 8644 alone increased (+)-[3H]PN 200-110 binding. These results suggest that chronic exposure to ethanol increases Ca2+ channel antagonist receptor density in living neural cells, but that acute inhibition of Ca2+ flux by ethanol is unlikely to trigger this response.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1989

Expression of a pseudocapsule by Staphylococcus aureus: influence of cultural conditions and relevance to mastitis.

Strains of Staphylococcus aureus from cases of mastitis in ruminants were cultured in various media and the cells examined electron microscopically for a pseudocapsule. Organisms grown inside the udder, or in nutrient broth supplemented with ovine, bovine or caprine milk whey produced a large, well-defined pseudocapsule outside the cell wall, but such cells had no true capsule when tested by the India ink technique. Modified staphylococcus 110 medium induced secretion by the organisms of copious extracellular slime but did not induce the pseudocapsule. Organisms grown in the presence of milk whey showed a strong propensity to autoagglutinate and produced pseudocapsular material which contained antigens in common with staphylococci grown in vivo. Supplementing media with lactose, dextrose or casein failed to modify the cell surface of S aureus in a manner analogous to that induced by ruminant whey.

Agglutination Tests↗
PubMed1989

Ovine opsonins for Staphylococcus aureus cell wall and pseudocapsule.

Blood serum, milk whey and purified IgG1 and IgG2 antibody preparations from sheep immunised with live or killed Staphylococcus aureus vaccines were assayed for opsonising activity against S aureus using ovine mammary neutrophils as effector cells. Serum had much higher levels of opsonins than whey; whey did not inhibit the potent opsonising activity of hyperimmune serum. IgG1 antibodies against cell wall antigens of in vitro-grown S aureus and pseudocapsular antigens of in vivo-grown S aureus had low opsonising activity. IgG2 antibody against in vitro-grown S aureus surface antigens had significantly greater opsonising activity than IgG1 of this specificity. The most powerful opsonising activity was associated with IgG2 antibody against the pseudo-capsular antigens produced by S aureus grown under in vivo, or simulated in vivo cultural conditions.

Animals↗
PubMed1989

Bromocriptine mesylate for lactation suppression: a risk for postpartum hypertension?

The etiology of postpartum eclampsia and hypertension remains controversial. Recent reports have suggested a possible idiosyncratic hypertensive reaction associated with the use of bromocriptine mesylate. The purpose of this study was to determine whether bromocriptine, used for lactation suppression, is a risk factor for postpartum hypertension. In 1813 consecutively delivered staff patients, blood pressures at three separate home visits were obtained between 3-21 days postpartum. Postpartum hypertension, defined for the purposes of this study as systolic pressure of 140 mmHg or greater and/or diastolic pressure of 90 mmHg or greater on any of the three home visits, was the dependent variable; bromocriptine exposure was the independent variable. Covariates included age, race, chronic hypertension, pregnancy-induced hypertension, and antihypertensive medication. Discriminant analysis, including the first-order interactions, revealed that race, history of chronic hypertension, pregnancy-induced hypertension, and antihypertensive medication contributed significantly to postpartum hypertension (F (7, 1803) = 107.9; P less than .001, explained variance 30%). Of all the interaction terms, only the bromocriptine by pregnancy-induced hypertension interaction was significant. These findings support the contention that patients with antepartum pregnancy-induced hypertension who receive bromocriptine for lactation suppression are at increased risk for postpartum hypertension. Avoiding the elective use of this drug in patients with pregnancy-induced hypertension might constitute a reasonable clinical response to these findings.

Adult↗
PubMed1988

Dextromethorphan and dextrorphan as calcium channel antagonists.

Dextromethorphan and dextrorphan, which reduce excitatory amino acid-induced neurotoxicity, decreased K+ depolarization-evoked 45Ca2+ uptake into brain synaptosomes and cultured neural (PC12) cells. Half-maximal inhibition of synaptosomal 45Ca2+ uptake occurred with 48 microM dextromethorphan or 200 microM dextrorphan, which are similar to concentrations associated with protection from excitotoxicity. The ability to decrease Ca2+ flux through N-type (synaptosomal) and L-type (PC12) voltage-gated Ca2+ channels may therefore contribute to the neuroprotective effects of these compounds.

Animals↗
PubMed1988

Striatal calcium channel antagonist receptors in Huntington's disease and Parkinson's disease.

The density of calcium channel antagonist receptors labeled by (+)-[3H]PN 200-110 was reduced by 75% in striata from patients with Huntington's disease, but unchanged in patients with Parkinson's disease, compared with control subjects. These receptors are therefore likely to be localized to neurons with cell bodies in striatum, rather than nigrostriatal nerve terminals or glia, and their loss may contribute to the pathophysiology of basal ganglia disorders.

Aged↗
PubMed1988

Transport of serum IgA into bile of sheep infected with Fasciola hepatica.

Sheep infected with Fasciola hepatica were studied for their ability to transport intravenously injected radiolabelled IgA from serum to bile. The results show that there was an apparent reduction in the selectivity of transport of IgA into bile in infected animals compared with uninfected controls. However, in infected animals the biliary flow rate was approximately twice that of uninfected animals, and the total amount of radiolabelled IgA transported was similar irrespective of infection status. The possible relevance of the elevated biliary flow rate is discussed with respect to the pharmacokinetics of drugs used for the chemotherapy of helminth infections in sheep.

Animals↗
PubMed1988

Immunological cross-reactivity between pseudocapsular antigens of strains of Staphylococcus aureus isolated from cases of bovine mastitis.

An assay was developed to measure the degree of immunological cross-reactivity between the pseudocapsules of a vaccine (reference) strain of Staphylococcus aureus and pseudocapsules of strains of S. aureus isolated from cases of bovine mastitis. The field strains were obtained from Australia, New Zealand, Norway, the U.K. and the U.S.A. There was large variation among strains in cross-reactivity of their pseudocapsules with those of the reference strain. For 104 Australian strains, the range of cross-reactivity indices (CRI) was 6.1-63.2% (on a scale of 0-100%, with 0% being complete identity and 100% being nil identity); for 61 overseas strains the range of CRI values was 25.7-72.1%. The data indicated that pseudocapsule antigens of Australian strains were antigenically more closely related to those of the reference strain than were pseudocapsular antigens of strains from the 4 other countries.

Animals↗
PubMed1988

Immunoglobulin isotype influences traffic of B lymphocytes through popliteal lymph nodes in sheep.

The antigen specificity of blast B lymphocytes was used to trace their passage from blood through antigenically naive popliteal lymph nodes in sheep. Ovine popliteal nodes selectively recruited lymphocytes containing IgG1 in preference to those containing IgG2. This selection appeared to operate at the level of the vascular endothelium. Stimulation of lymph nodes with killed S. aureus and dextran sulphate (DXS) (which promotes an antibody response in ovine lymph nodes biased in favour of IgG2) did not significantly alter this pattern.

Animals↗