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Biomedical subjects

G K Davis

Publications and source records attributed to G K Davis.

At least 19 recordsLinked to original sources
PubMed2003

Role of cardiac troponin testing in percutaneous transluminal coronary angioplasty.

Percutaneous transluminal coronary angioplasty (PTCA) is a common invasive procedure for myocardial revascularization. This article reviews the role of monitoring cardiac troponins in identifying procedural myocardial damage as a result of PTCA, its associations with balloon inflation time, stenting, side-branch occlusion and the prognostic implications of elevated levels of cardiac troponins. A review of several studies demonstrates that cardiac troponins are more sensitive than creatine kinase MB, CK-MB (mass) in detecting minor myocardial damage during PTCA. Increases in post-procedural cardiac troponin T and cardiac troponin I are associated with a greater degree of morbidity and mortality. Increases are more common and more pronounced following a longer duration of balloon inflation time, stenting and side-branch occlusion. Elevated cardiac troponins pre-procedure are a poor prognostic indicator.

Angioplasty, Balloon, Coronary↗
PubMed2001

Twenty-four-hour automated blood pressure monitoring as a predictor of preeclampsia.

OBJECTIVE: The purpose of this study was to determine the predictive ability of parameters of 24-hour ambulatory blood pressure monitoring for the development of preeclampsia or gestational hypertension in women who are already considered at risk for these disorders. STUDY DESIGN: One hundred twenty-two pregnant women who were considered high risk for the development of preeclampsia underwent 24-hour ambulatory blood pressure monitoring between 18 and 30 weeks gestation, while their condition was normotensive according to routine mercury sphygmomanometry. One hundred sixty-four healthy primigravid women who were considered at usual risk for preeclampsia underwent the same tests as a parallel study. Routine blood pressure, awake and sleep average blood pressure, and 24-hour mean average blood pressure were entered into multiple logistic regression as predictors of either preeclampsia or gestational hypertension; significant variables were then tested by a series of receiver operator curves. RESULTS: Eight percent of usual risk and 45% of high risk women experienced the development of preeclampsia or gestational hypertension. In both groups, the average routine mercury blood pressure and awake, sleeping, and 24-hour ambulatory blood pressure monitoring-derived blood pressure were significantly higher in women who later experienced the development of preeclampsia or gestational hypertension. In usual risk women, 24-hour systolic blood pressure of >or=115 mm Hg and sleeping systolic blood pressure of >or=106 mm Hg were predictive of later preeclampsia or gestational hypertension, but sensitivities were low (77% and 54%, respectively). In high risk women, sleeping diastolic blood pressure of >or=62 mm Hg and sleeping mean arterial pressure of >or=79 mm Hg were predictive of preeclampsia or gestational hypertension, but again sensitivities were low (70% and 65%, respectively). CONCLUSION: Awake and sleeping blood pressure are higher in midpregnancy in women who later experience the development of preeclampsia or gestational hypertension. Twenty-four-hour ambulatory blood pressure monitoring provides a noninvasive method of selecting some of these women, but this test has a sensitivity no better than that of other predictive tests, even in women at high risk for preeclampsia.

Adult↗
PubMed2001

Community-based continuity of midwifery care versus standard hospital care: a cost analysis.

This paper reports the costs of providing a new model of maternity care compared to standard care in an Australian public hospital. The mean cost of providing care per woman was lower in the group who had the new model of care compared with standard care ($2,579 versus $3,483). Cost savings associated with new model of care were maintained even after costs associated with admission to special care nursery were excluded. The cost saving was also sustained even when the caesarean section rate in the new model of care increased to beyond that of the standard care group.

Community Health Services↗
PubMed2001

The prevalence and clinical significance of nocturnal hypertension in pregnancy.

OBJECTIVE: To determine (a) the prevalence of hypertension during sleep in pre-eclampsia and gestational hypertension, and (b) whether women with hypertension during sleep have worse pregnancy outcomes than hypertensive pregnant women with controlled (normal) blood pressure (BP) during sleep. DESIGN: Prospective double-blind cohort study. SETTING: Inpatients and outpatients managed in a day assessment unit (DAU) at St George Hospital, Sydney, Australia. PARTICIPANTS: A total of 186 hypertensive pregnant women, 158 of whom had successful 24 h BP monitoring; 40% had proteinuric pre-eclampsia (PE), 43% gestational hypertension (GH) and 17% essential hypertension (EH). INTERVENTIONS: Blood pressure, 24 h non-invasive, monitoring (Spacelabs 90207) was undertaken successfully in 158 women with PE, GH or EH, whether or not they were receiving antihypertensives. Women and clinicians were blinded to results of these BP monitors. Sleep hypertension was defined as BP > 117/68 mmHg at 26-30 weeks or > 123/72 mmHg after 30 weeks gestation. MAIN OUTCOME MEASURES: Maternal and fetal outcomes were compared between women with and without sleep hypertension and the prevalence of sleep hypertension was determined. RESULTS: Sleep hypertension was present in 59%, more commonly in PE (79%) than GH/EH (45%), P < 0.0001. Sleep hypertensives also had higher routine sphygmomanometer BPs [137(10)/91(7) mmHg; mean(SD)] than women with normal sleep BP [130(12)/ 87(8) mmHg] P = 0.007, and higher awake ambulatory blood pressure monitoring (ABPM) BPs [137(8)/88(7) versus 127(7)/79(6) mmHg], P < 0.0001. Awake, but not sleep, average heart rate was lower in sleep hypertensives [85(11) versus 91 (10) beats per minute, bpm], P = 0.002. Sleep hypertensives had a significantly greater frequency of renal insufficiency, liver dysfunction, thrombocytopenia and episodes of (awake) severe hypertension (P < 0.05), as well as lower birth weight babies [2715 (808) versus 3224(598) g, P < 0.0001]. CONCLUSIONS: Hypertension during sleep is a common finding in women with hypertensive disorders of pregnancy, particularly pre-eclampsia. These women also have higher awake BPs and a greater frequency of adverse maternal and fetal outcomes. These findings are largely explained by the greater likelihood of pre-eclamptics having sleep hypertension.

Adult↗
PubMed2001

Collaboration in maternity care: a randomised controlled trial comparing community-based continuity of care with standard hospital care.

OBJECTIVE: To test whether a new community-based model of continuity of care provided by midwives and obstetricians improved maternal clinical outcomes, in particular a reduced caesarean section rate. DESIGN: Randomised controlled trial. SETTING: A public teaching hospital in metropolitan Sydney, Australia. Sample 1089 women randomised to either the community-based model (n = 550) or standard hospital-based care (n = 539) prior to their first antenatal booking visit at an Australian metropolitan public hospital. MAIN OUTCOME MEASURES: Data were collected on onset and outcomes of labour, antenatal, intrapartum and postnatal complications, antenatal admissions to hospital and neonatal mortality and morbidity. RESULTS: There was a significant difference in the caesarean section rate between the groups, 13.3% (73/550) in the community-based group and 17.8% in the control group (96/539). This difference was maintained after controlling for known contributing factors to caesarean section (OR = 0.6, 95% CI 0.4-0.9, P = 0.02). There were no other significant differences in the events during labour and birth. Eighty babies (14.5%) from the community-based group and 102 (18.9%) from the control group were admitted to the special care nursery, but this difference was not significant (OR 0.75, 95% CI 0.5-1.1, P = 0.12). Eight infants died during the perinatal period (four from each group), for an overall perinatal mortality rate of 7.3 per 1000 births. CONCLUSION: Community-based continuity of maternity care provided by midwives and obstetricians resulted in a significantly reduced caesarean section rate. There were no other differences in clinical outcomes.

Adult↗
PubMed2001

Introducing external cephalic version to clinical practice.

A service offering external cephalic version to all women with breech presentations at 36-38 weeks' gestation was introduced at St George Hospital in July 1997. This paper describes how this service was established and reports the clinical outcomes over the first three years; 116 external cephalic versions (ECV) were attempted on 114 women and success was achieved in 58 women (51%). Of the 58 women, 43 (74%) subsequently had vaginal deliveries. There were no fetal deaths, immediate Caesarean sections, or placental abruptions as a result of the ECV procedure. There were two (2%) episodes of transient fetal bradycardia following ECV, both of which returned to normal with a subsequent normal neonatal outcome. Pre- and post-ECV Kleihauer levels were collected with no increase in levels as a result of the ECV ECV is a procedure that can, and should, be provided as part of a public hospital service.

Adult↗
PubMed2001

Pax group III genes and the evolution of insect pair-rule patterning.

Pair-rule genes were identified and named for their role in segmentation in embryos of the long germ insect Drosophila. Among short germ insects these genes exhibit variable expression patterns during segmentation and thus are likely to play divergent roles in this process. Understanding the details of this variation should shed light on the evolution of the genetic hierarchy responsible for segmentation in Drosophila and other insects. We have investigated the expression of homologs of the Drosophila Pax group III genes paired, gooseberry and gooseberry-neuro in short germ flour beetles and grasshoppers. During Drosophila embryogenesis, paired acts as one of several pair-rule genes that define the boundaries of future parasegments and segments, via the regulation of segment polarity genes such as gooseberry, which in turn regulates gooseberry-neuro, a gene expressed later in the developing nervous system. Using a crossreactive antibody, we show that the embryonic expression of Pax group III genes in both the flour beetle Tribolium and the grasshopper Schistocerca is remarkably similar to the pattern in Drosophila. We also show that two Pax group III genes, pairberry1 and pairberry2, are responsible for the observed protein pattern in grasshopper embryos. Both pairberry1 and pairberry2 are expressed in coincident stripes of a one-segment periodicity, in a manner reminiscent of Drosophila gooseberry and gooseberry-neuro. pairberry1, however, is also expressed in stripes of a two-segment periodicity before maturing into its segmental pattern. This early expression of pairberry1 is reminiscent of Drosophila paired and represents the first evidence for pair-rule patterning in short germ grasshoppers or any hemimetabolous insect.

Amino Acid Sequence↗
PubMed2000

Angiotensin converting enzyme (ACE) gene expression in the human left ventricle: effect of ACE gene insertion/deletion polymorphism and left ventricular function.

AIMS: We investigated the effect of the angiotensin converting enzyme (ACE) I/D polymorphism and left ventricular (LV) function on ACE gene expression in tru-cut LV myocardial biopsies from 50 consecutive patients (II: 18, ID: 18, DD: 14; 40 males) with ischaemic heart disease undergoing coronary artery bypass grafting (CABG). METHODS: The polymerase chain reaction was used for ACE genotyping. LV function [normal (n=22) or impaired] was determined by left ventriculography at cardiac catheterisation prior to bypass surgery. ACE expression was determined (n=46) by a competitive quantitative reverse transcription PCR assay using 5x10(5), 12. 5x10(5) and 20x10(5) copies of a mutant DNA internal standard (IS). PCR products were analysed by negative film photography and laser densitometry to determine the number of ACE transcripts present. RESULTS: Mean age was similar (II: 59.1+/-10.4, ID: 57.0+/-10.6, DD: 61.4+/-6.2; P=NS) with no differences between groups in sex (P=0. 25); hypertension, P=0.31; previous myocardial infarction, P=0.44; LV function, P=0.23; and ACE inhibitor therapy, P=0.06. ACE expression per 100 ng of total RNA varied with genotype [<5x10(5) copies in II: 6, 5-12.5x10(5) copies in II: 6, ID: 16, DD: 4; and >12.5x10(5) (II: 4, ID: 2, DD: 8), Kendall's tau-b coefficient (tau(b))=0.43, P=0.003]. Impaired LV function also correlated with higher levels of ACE expression, Kendall's tau(b)=0.40, P=0.001. CONCLUSION: ACE gene expression in the left ventricle varied with ACE genotype and LV function in IHD patients undergoing CABG.

Female↗
PubMed2000

What do women feel about community-based antenatal care?

OBJECTIVE: This study evaluated women's perceptions of a new community-based model of continuity of antenatal care, the St George Outreach Maternity Project (STOMP). The model was established in an attempt to address some of the ongoing concerns and criticisms regarding antenatal care in Australia: lack of continuity of care and caregiver; prolonged waiting times; and inaccessible clinics. METHODS: A randomised controlled trial was conducted with 1,089 women (550 in the experimental group and 539 in the control group). The experimental group (the STOMP group) received antenatal care from small teams of midwives and an obstetrician in community-based settings. Data were collected using a questionnaire administered at 36 weeks' gestation, with a response rate of 75%. RESULTS: Women in the STOMP group reported waiting significantly less time for antenatal visits with easier access to care. STOMP group women also reported a higher perceived 'quality' of antenatal care compared with the control group. STOMP group women saw slightly more midwives and fewer doctors than control group women did. CONCLUSION AND IMPLICATIONS: This model of care has implications for the planning and provision of antenatal services within the Australian public health system, which is increasingly moving towards a community-based emphasis. Antenatal care is a service that can be successfully transferred into community-based settings with benefits for women.

Adult↗
PubMed2000

Management of acute myocardial infarction in the public sector in the Bahamas.

In 1996 and 1997, 52 patients were admitted to the Princess Margaret Hospital, Nassau, Bahamas, with a confirmed diagnosis of acute myocardial infarction (AMI). The average time to presentation after the onset of symptoms was 18 hours, with 56% of patients presenting within 12 hours. Risk factors identified for ischaemic heart disease were hypertension (77%), obesity (62%), diabetes mellitus (35%), tobacco smoking (25%), a family history of coronary artery disease (17%) and hypercholesterolaemia (8%). Medications administered in the treatment of AMI included oral nitrates (96%), intravenous heparin (90%), beta-blockers (65%), morphine (15%), thrombolytic agents (8%) and lignocaine (4%). In hospital post myocardial infarction complications were angina (23%), arrhythmias (12%) and cardiac failure (10%). The average hospital stay was eight days, with a mortality rate of 19%. These results show that there is considerable room for improvement, particularly in the use of thrombolytic therapy, to ensure that all patients receive optimal acute and post myocardial infarction care.

Adult↗
PubMed1999

The introduction of a woman-held record into a hospital antenatal clinic: the bring your own records study.

We report the introduction of a woman-held record into an antenatal clinic in a NSW teaching hospital using a randomized controlled trial. In 1997, 150 women were randomized to either retaining their entire antenatal record through pregnancy (women-held group) or to holding a small, abbreviated card, as was standard practice (control group). A questionnaire was distributed to women to measure sense of control, involvement in care and levels of communication. Availability of records at antenatal visits was also measured. Women in both groups were satisfied with their allocated method of record keeping, however, those in the women-held group were significantly more likely to report feeling in 'control' during pregnancy. Women in the control group were more likely to feel anxious and helpless and less likely to have information on their records explained to them by their caregiver. The number of records available at each clinic was similar in both groups.

Adult↗
PubMed1999

The origin and evolution of segmentation.

Arthropods, annelids and chordates all possess segments. It remains unclear, however, whether the segments of these animals evolved independently or instead were derived from a common ancestor. Considering this question involves examining not only the similarities and differences in the process of segmentation between these phyla, but also how this process varies within phyla, where the homology of segments is generally accepted. This article reviews what is known about the segmentation process and considers various proposals to explain its evolution.

Animals↗
PubMed1997

Molecular genetics of the renin-angiotensin system: implications for angiotensin II receptor blockade.

Angiotensin II (Ang II) is the main effector hormone of the renin-angiotensin system (RAS). The pathogenesis of many cardiovascular diseases, including heart failure and hypertension, appear to be related to Ang II production. The generation of Ang II involves angiotensin-converting enzyme (ACE) in circulating and tissue RAS's, as well as non-ACE pathways. ACE and other components of the RAS show natural mutations. In this review, we discuss the molecular genetics of the human RAS in relation to cardiovascular disease, including the clinical effects of known ACE molecular variants and possible pharmacological treatment strategies.

Angiotensin II↗