Search PubMed⌕ Search

Biomedical subjects

P M Kyle

Publications and source records attributed to P M Kyle.

At least 37 records · Page 2Linked to original sources
PubMed1996

Amniotic fluid culture failure: clinical significance and association with aneuploidy.

OBJECTIVE: To characterize clinical aspects associated with second-trimester amniotic fluid (AF) culture failure. METHODS: The reports of all amniocentesis samples received in our cytogenetic laboratory over a 9-year period were reviewed to identify cases in which culture failure of amniocytes occurred. Medical records were then reviewed for the prenatal ultrasonographic findings, karyotype when available, and clinical outcome. RESULTS: During the study period, 4134 second-trimester AF samples were processed, of which 42 (1%) failed to yield a result. Complete information was available in 41 pregnancies, which are the basis of this report. Karyotyping was done ultimately in 32 of the 41 cases (78%). The frequency of an abnormal karyotype was greater in those pregnancies in which AF culture failure occurred in comparison with those in which a cytogenetic result was obtained (six of 32 [19%] versus 149 of 4092 [4%], P < .001). There was also a greater prevalence of fetal abnormalities detected on prenatal ultrasonography, mainly oligohydramnios, hydrops, and fetal growth restriction, in the AF culture failure group compared with the successful AF culture group (17 of 41 [41%] versus 351 of 4092 [9%1, P < .001). All chromosomally abnormal fetuses had anomalies detected at ultrasonography. CONCLUSION: Our findings confirm the previously reported association between karyotype abnormality and AF culture failure, but suggest that this association is probably due to fetal anomalies, detectable on prenatal ultrasonography, that lead to decreased fetal cell shedding.

Amniocentesis↗
PubMed1996

High failure rate of postmortem karyotyping after termination for fetal abnormality.

OBJECTIVE: To determine the failure rate of karyotyping from samples taken after termination of pregnancy for fetal abnormality. METHODS: Perinatal autopsy reports over a 12-month period were reviewed to identify those with cytogenetic studies performed after termination of pregnancy for fetal abnormality. RESULTS: During the audit period, there were 104 terminations for fetal abnormality. In 89 fetuses, fetal skin (n = 85), placenta (n = 62), or other samples (n = 8) were obtained for postmortem cytogenetic analysis. In 24 (27%) fetuses, postmortem tissues did not yield a karyotype result. The failure rate of post-termination karyotyping was significantly influenced by delivery-sampling interval, but not by gestational age, type of tissue sampled, use of potassium chloride, or aneuploidy. Of the 24 cases for which no post-termination karyotype was obtained, 16 had had successful pre-termination karyotyping, resulting in only eight of 89 (9%) cases in the overall series not having a final karyotype. CONCLUSION: The high failure rate for post-termination karyotyping suggests that a pre-termination procedure is necessary if parents wish to have almost 100% certainty that cytogenetic information will be available for later genetic counseling.

Abortion, Induced↗
PubMed1996

A comparison of the inactive urinary kallikrein:creatinine ratio and the angiotensin sensitivity test for the prediction of pre-eclampsia.

OBJECTIVE: To determine the relation between the inactive urinary kallikrein: creatinine ratio (IUK:Cr) and the angiotensin sensitivity test (AST) at 28 weeks of gestation and to assess each as a screening test for pre-eclampsia. DESIGN: Prospective interventional study. SUBJECTS: Four hundred and fifty-nine normotensive nulliparous women recruited from hospital antenatal clinics. SETTING: John Radcliffe Maternity Hospital, Oxford, and Queen Charlotte's and Chelsea Hospital, London. INTERVENTIONS: A urine sample for IUK:Cr measurement was provided before performing the AST at 28 weeks of gestation. Those women who demonstrated increased sensitivity to angiotensin II were entered into a randomised placebo controlled trial of low dose aspirin for the prevention of pre-eclampsia (CLASP). MAIN OUTCOME MEASURES: The development of pre-eclampsia. RESULTS: The IUK:Cr ratio was significantly lower in those women who showed increased sensitivity to angiotensin II (P < 0.0001 Student's t test). The sensitivity and specificity for detecting pre-eclampsia were, respectively, 22% and 85% for the AST and 67% and 75% for the IUK:Cr. Low-dose aspirin (60 mg) had no effect on the pregnancy outcome. CONCLUSION: There appears to be some relation between the IUK:Cr and AST tests in pregnancy. However, in this population, the IUK:Cr ratio was a better screening test for pre-eclampsia than the AST, but overall neither test was a powerful predictor for the syndrome.

Angiotensin II↗
PubMed1995

The angiotensin sensitivity test and low-dose aspirin are ineffective methods to predict and prevent hypertensive disorders in nulliparous pregnancy.

OBJECTIVE: Our purpose was to assess the efficiency of the angiotensin sensitivity test as a predictive test for preeclampsia and the effectiveness of low-dose aspirin to prevent preeclampsia when commenced at 28 weeks' gestation in angiotensin II-sensitive women. STUDY DESIGN: A total of 495 healthy nulliparous women underwent the angiotensin sensitivity test at 28 weeks' gestation. The angiotensin II-sensitive women were randomized to 60 mg of aspirin or placebo as a subset of a large multicenter, randomized, controlled trial of low-dose aspirin therapy in pregnancy. Assessment of the efficiency of the angiotensin sensitivity test and low-dose aspirin in pregnancy was performed after detailed review of case notes after delivery. The Oxford definition of preeclampsia was used. This includes women without proteinuria but requires blood pressure increments that have been validated to bias the selection to primigravid women. RESULTS: Five women had proteinuric preeclampsia in the angiotensin II-sensitive group randomized to aspirin compared with none in the group randomized to placebo. Overall, 11 (25%) of the women randomized to aspirin had preeclampsia compared with four (11%) randomized to placebo (p < 0.05, not significant). The positive and negative predictive values for the angiotensin sensitivity test were 19% and 87%, respectively. CONCLUSION: The angiotensin sensitivity test is not an effective screening test for preeclampsia, and low-dose aspirin does not prevent preeclampsia when commenced at 28 weeks' gestation in angiotensin II-sensitive women.

Angiotensin II↗
PubMed1995

Platelet intracellular free calcium response to arginine vasopressin is similar in preeclampsia and normal pregnancy.

OBJECTIVE: Our purpose was to compare the effect of arginine vasopressin stimulation on platelet free intracellular calcium levels in normal pregnancy, incipient preeclampsia, and established preeclampsia. STUDY DESIGN: Cross-sectional and prospective observational study designs were used. Platelet free intracellular calcium was measured by flow cytometry in 10 nonpregnant female volunteers, 10 women with established preeclampsia and their normal pregnant matched controls, and 64 normal pregnant women at 28 weeks' gestation. All pregnant women were nulliparous. RESULTS: Increased response to arginine vasopressin stimulation was observed in nonpregnant compared with pregnant women (p < 0.001). No differences were observed between women with normal pregnancy, incipient preeclampsia, or established preeclampsia. CONCLUSION: The platelet intracellular free calcium response to arginine vasopressin is not a feature of incipient or established preeclampsia. Therefore, in contrast to a previous report, it does not appear to have value as a predictive test for preeclampsia.

Adolescent↗
PubMed1995

Long-term visual outcome following orbital decompression for dysthyroid eye disease.

The records of 33 patients who had undergone inferior and medial wall orbital decompressions for compressive optic neuropathy due to dysthyroid eye disease were reviewed. The indication for surgery in 32 patients was a reduction in Snellen visual acuity. The remaining patient had bilateral optic disc swelling but normal visual acuity. Twenty-nine patients (88%) were treated with systemic steroids pre-operatively, which resulted in an improvement in vision in all cases. In the immediate post-operative period visual acuity either improved or the steroid-induced visual improvement was maintained as the steroids were tailed off. Long-term visual outcome, however, varied. In 19 patients (58%) visual acuity was maintained with no requirement for additional treatment. In 12 patients (36%) there was a subsequent deterioration in vision which responded to additional treatment with either systemic steroids, orbital radiotherapy or further orbital surgery. In 2 patients (6%) vision continued to deteriorate despite further treatment. We conclude that although orbital decompression has resulted in the long-term preservation of visual acuity in 94% of our patients, there remains a small subgroup (6%) in whom visual function continues to deteriorate despite all forms of treatment.

Adult↗
PubMed1995

Flow cytometric detection of activated platelets in pregnant women prior to the development of pre-eclampsia.

Pre-eclampsia is a common complication of pregnancy, in which platelets may have an early pathogenetic role. In this prospective study a whole blood flow cytometric method has been used to detect circulating activated platelets in pregnant women prior to the development of pre-eclampsia. Activated platelets were identified by bound fibrinogen or by CD63 antigen expression. Of 121 healthy primiparous women studied at 28 weeks of pregnancy, 18 (15%) developed clinical pre-eclampsia six to thirteen weeks later. The platelets of these women showed increased fibrinogen binding ex vivo (5.1% platelets positive, compared with 3.4% in those who completed a normal pregnancy, p < 0.02), and increased CD63 antigen expression (0.73% positive compared to 0.45%, p = 0.01). In contrast, no differences between the women with different outcomes were detected at 28 weeks in platelet counts, or plasma beta-thromboglobulin levels. These findings confirm that whole blood flow cytometry is a sensitive technique for investigating platelet activation in a clinical setting and support the hypothesis that platelets have a critical role in the pathogenesis of pre-eclampsia.

Antigens, CD↗
PubMed1994

Life without amniocentesis: elevated maternal serum alpha-fetoprotein in the Manitoba program 1986-91.

Pregnant women demonstrating an elevated maternal serum alpha-fetoprotein level are at increased risk for fetal neural tube defect or other anomaly. Diagnostic procedures to evaluate these pregnancies include high-resolution ultrasound and amniocentesis to measure amniotic fluid levels of alpha-fetoprotein and N-acetylcholinesterase. We wished to examine the efficacy of detailed ultrasound examination alone, in evaluation of women with 'unexplained' elevation of maternal serum alpha-fetoprotein. The results showed that no neural tube defects were missed in the assessment of 1325 pregnancies with a raised level of maternal serum alpha-fetoprotein over 6 years, despite complete reliance on ultrasound in 98%. Detailed fetal ultrasound evaluation by experienced personnel is adequate to identify all cases of neural tube defects in a selected high-risk population.

Journal Article↗
PubMed1993

Noninvasive assessment of the maternal cerebral circulation by transcranial Doppler ultrasound during angiotensin II infusion.

OBJECTIVE: To examine the relationship between experimentally induced increments in blood pressure and maternal middle cerebral artery flow velocity patterns measured by transcranial Doppler ultrasound (TCD). DESIGN: Prospective experimental study. SETTING: John Radcliffe Maternity Hospital, Oxford. INTERVENTION: Middle cerebral artery flow velocity waveforms were measured using 2 MHz pulsed Doppler ultrasound via the temporal cranial approach at 28 weeks gestation before, during and 10 min following an angiotensin II infusion. SUBJECTS: 101 normotensive primiparous women at 28 weeks gestation. RESULTS: A significant rise in blood pressure and fall in heart rate were demonstrated between pre-infusion and maximum angiotensin II infusion (maximum blood pressure) recordings. Simultaneous changes were observed in all flow velocity indices, shown as a decrease in systolic velocity and pulsatility index, and an increase in diastolic and mean velocity (P < 0.0001). These values all returned to baseline levels 10 min post infusion (P < 0.0001). Statistical analysis suggested that the change in flow velocity is related to the rise in blood pressure rather than the direct effect of angiotensin II on the cerebral circulation. CONCLUSION: Transcranial Doppler can detect changes in the cerebral circulation associated with alterations in blood pressure during pregnancy. The technique needs to be evaluated further in hypertensive disease.

Adult↗
PubMed1993

Second trimester ambulatory blood pressure in nulliparous pregnancy: a useful screening test for pre-eclampsia?

OBJECTIVE: To assess the effectiveness of second trimester 24-hour ambulatory blood pressure measurement as a screening test for pre-eclampsia. DESIGN: Prospective interventional study. SETTING: John Radcliffe Maternity Hospital, Oxford, and Queen Charlotte's and Chelsea Hospital, London. SUBJECTS: One hundred and sixty-two normotensive nulliparous women recruited at hospital booking clinics. INTERVENTION: Ambulatory blood pressure was measured at 18 and 28 weeks gestation using the TM2420 monitor. MAIN OUTCOME MEASURE: The development of pre-eclampsia. RESULTS: Awake systolic and mean arterial pressures were significantly increased (P < 0.02) at 18 weeks in those who later developed pre-eclampsia. Those differences were more apparent at 28 weeks at which time the diastolic pressure was also increased (P < 0.01). At both stages of gestation the higher readings were sustained during sleep so that the awake-sleep differences were similar in relation to each outcome. The group with incipient pre-eclampsia had a significantly faster heart rate at both 18 and 28 weeks (P < 0.002) The sensitivity in predicting pre-eclampsia for a mean arterial pressure of 85 mmHg or greater at 28 weeks was 65%, with a positive predictive value of 31%. The sensitivity and positive predictive value for a test combining a mean arterial pressure of 85 mmHg or greater and a heart rate of 90 bpm or greater were 53% and 45%, respectively. CONCLUSION: Although second trimester ambulatory blood pressure is significantly increased in women who later develop pre-eclampsia, the predictive values for blood pressure alone are low. The efficiency of the test is increased by combining the awake ambulatory heart rate and blood pressure measurement together. If an effective method for preventing pre-eclampsia becomes available (commencing at 28 weeks gestation), then awake ambulatory blood pressure and heart rate may have some clinical value as a screening test.

Adolescent↗
PubMed1991

Delayed ciliochoroidal detachment following intraocular lens implantation.

Three patients who had extracapsular cataract extractions with intraocular lens implants developed delayed ciliochoroidal detachments, which responded to systemic steroid therapy. This rare complication may have been due to ciliary sulcus fixation of the implant. The possible mechanism and treatment are discussed.

Aged↗
PubMed1984

Routes of clearance of radioactive water from the rabbit vitreous.

The movement of water to and from the vitreous across the retina and pigment epithelium is important in relation to an understanding of such conditions as retinal detachment and its surgical cure, central serous retinopathy, and retinal oedema. Experiments were carried out to determine the main routes for removal of water injected into the vitreous and to see if the removal could be explained on the basis of diffusion or whether bulk flow was also implicated. 25 microCi of 3H2O in 25 microliter were injected into a central position in the vitreous humour of living rabbits under general anaesthesia. For 9 animals blood was collected from one of the 4 vortex veins draining the choroid and the radioactivity in the samples measured. For another 6 rabbits similarly injected the radioactivity in samples of aqueous humour was determined. The percentage of injectate recovered from the vortex vein blood ranged between 13% and 38%, mean 25 +/- 3%. The percentage of injectate recovered from the aqueous humour ranged between 1.2% and 5.2%, mean 2.8 +/- 0.6%. Analysis of the time course of isotope activity in the samples revealed a mean transit time from the mid vitreous to the choroid of 32 +/- 2 minutes, and from the mid vitreous to the anterior chamber of 84 +/- 3 minutes. By means of a computer model it was calculated that diffusion alone could effect this transfer; if active transport were involved in the transport of 3H2O to the choroid, this was not a limiting factor under the conditions of the experiment.

Animals↗