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Biomedical subjects

M J Maresh

Publications and source records attributed to M J Maresh.

16 recordsLinked to original sources
PubMed2000

Glycemic control throughout pregnancy and fetal growth in insulin-dependent diabetes.

OBJECTIVE: To determine the time of growth acceleration in fetuses of insulin-dependent diabetic women who are large for gestational age (LGA) at birth and the relationship between growth acceleration and diabetic control throughout pregnancy. METHODS: We studied a consecutive sample of 76 women with insulin-dependent diabetes divided by those who delivered LGA or normally grown infants. Fetal abdominal circumference (AC) was measured ultrasonically at regular intervals between 20 and 34 weeks' gestation. Diabetic control was assessed by regular measurement of glycosylated hemoglobin and capillary blood glucose levels. RESULTS: A significant difference in fetal AC between groups developed between 20 and 24 weeks' gestation, and the LGA group continued to have accelerated fetal growth. Between 18 and 24 weeks glycosylated hemoglobin and capillary blood glucose concentrations were significantly higher in women who delivered LGA infants. After 28 weeks, blood glucose concentrations and glycosylated hemoglobin did not differ significantly between groups. There was a nonsignificant trend toward more vaginal deliveries in the normal group (45% versus 32%). CONCLUSION: In insulin-dependent diabetic pregnancy, although actual growth acceleration occurred from about 20 weeks' gestation, growth potential of fetuses appeared to be determined by prevailing maternal glucose concentrations before then. Excessive growth continued despite subsequent satisfactory glucose control. If strict blood glucose control is maintained during first and second trimesters, it might reduce the incidence of LGA infants.

Abdomen↗
PubMed2000

Monitoring quality of audit in obstetrics and gynaecology.

OBJECTIVE: To develop a questionnaire to assess audit activity and to use it to evaluate systematically the quality of audit in obstetrics and gynaecology within NHS hospitals in the UK. DESIGN: Retrospective review of 212 consecutive questionnaires completed at hospital recognition committee visits for training accreditation, between 1 January 1993 and 31 August 1998, validated against hospital trust annual audit reports. MAIN MEASURES: Use of seven quality criteria developed within the Royal College of Obstetricians and Gynaecologists clinical audit unit and also assessment of support for audit and participation in regional and national audit. Results were compared between 1993/4 (n = 72), 1995/6 (n = 72), and 1997/8 (n = 68) for evidence of improvement. RESULTS: After modifications to the questionnaire the version used from 1993 proved to be a satisfactory tool with minimal need for subsequent change. The results showed that there has been a significant improvement in the quality of obstetric and gynaecology audit with time (p < 0.0001) with 36 (53%) of departments in the previous two year period meeting all seven criteria. Similarly by this stage, 60 (88%) of departments had reached the stage of re-audit and 55 (81%) had conducted patient satisfaction surveys, both of these having significantly improved with time. Critical incident monitoring also became used more widely with time. Validation of topics audited was possible for 45% of hospitals where trust annual audit reports were available and these showed a high level of correlation. CONCLUSIONS: It has proved possible to conduct an audit of audit using the current system of hospital recognition visits for training accreditation. This has shown a great variety in the depth and breadth of audit that is being undertaken within individual obstetric and gynaecology departments. Since 1993 there has been an improvement in the quality of audit programmes undertaken, in particular in the number of hospitals carrying out critical incident monitoring, patient satisfaction surveys, and re-audit. This should be associated with improvements in staff training and in patient care.

Adult↗
PubMed1999

Antenatal screening by history taking--a missed opportunity.

In order to determine how effectively obstetricians and midwives identify and manage women at increased risk of fetal abnormality a case note review was undertaken. Two district general hospitals in each of two health regions and their tertiary referral centres making seven hospitals in all were studied. Women booked for antenatal care over a one-year period were included (19 895) which was estimated to be 75% of the total. Significant numbers of women at high risk because of age, past obstetric, medical or family history were not offered appropriate tests such as detailed scanning, carrier status testing, amniocentesis or chorion villus sampling. Asian women were less likely to be offered screening compared with Caucasians. Women at low risk were subjected to inappropriate tests such as amniocentesis. Ultrasound departments were rarely informed that a woman had had a previous baby with a structural abnormality. In conclusion the quality of booking histories was poor allowing important information about past medical, family or obstetric history to be overlooked. Maternity units should use carefully structured forms taking when booking histories and all staff must have regular training on risk factors.

Journal Article↗
PubMed1996

Detection of fetal fibronectin as a predictor of preterm delivery in high risk asymptomatic pregnancies.

OBJECTIVE: The study was designed to determine whether fetal fibronectin would predict delivery before 37 weeks in women at high risk of preterm delivery. STUDY METHODS: Forty-three women considered at risk of preterm delivery were recruited antenatally into a blind longitudinal study. Quantitative assays of fetal fibronectin were obtained from sequential high vaginal swabs taken fortnightly from 24 to 34 weeks of gestation. Fibronectin concentrations of 0.05 microgram/ml or more were considered as positive. RESULTS: Results were calculated by swab and by subject. The sensitivity of an individual fibronectin swab in predicting preterm delivery within 14 days of testing was 71% and the specificity was 93%. The overall positive predictive value was 31% and the negative predictive value was 99%. The sensitivity of the fibronectin swab in predicting delivery before 37 weeks was 17% and the specificity was 93%. The positive predictive value was 50% and the negative predictive value was 73%. For a woman who has had a positive swab the sensitivity in predicting preterm delivery within 14 days of testing was 80% and the specificity was 83%; a woman was counted as positive only if the final swab was positive and preceded delivery by not more than 14 days. The positive predictive value was 36% and the negative predictive value was 97%. For a woman who has had a positive swab the sensitivity in predicting delivery before 37 weeks was 54%. The specificity, the positive predictive value and the negative predictive value were 85%, 64% and 79%, respectively. Women were counted as positive if any swab in the sampling sequence was positive. Fibronectin swabbing when calculated by patient did predict preterm delivery within 14 days of testing (P=0.01) and before 37 weeks (P=0.01). Analysis of the accuracy of predicting delivery from 7 to 28 days after sampling revealed that the best prediction for delivery was within the following 14 days. CONCLUSION: Serial fetal fibronectin assessment from 24 to 34 weeks of gestation anticipated preterm delivery within 14 days of testing and before 37 weeks for high risk asymptomatic women. Such testing should be performed every two weeks.

Adult↗
PubMed1995

Audit of currently available endometrial ablative techniques.

Techniques for the treatment of menorrhagia have changed rapidly over the last few years. The enthusiastic introduction by a small number of protagonists of a variety of ablation/resection techniques has been followed by an exponential uptake in their use. At the same time there has been a period of critical appraisal by the Royal College of Obstetricians and Gynaecologists and the British Society for Gynaecological Endoscopy. The MISTLETOE Survey was the culmination of this association and has provided useful large data sets of the various techniques under evaluation. It is expected that recommendations concerning; the training of potential operators; various practical aspects of the surgical, medical and anaesthetic techniques required to undertake the procedures safely; types and frequencies of complications of the procedures, and success rates following the widespread use of these procedures will be made available following analysis of the data sets.

Catheter Ablation↗
PubMed1994

Altered activity of the system A amino acid transporter in microvillous membrane vesicles from placentas of macrosomic babies born to diabetic women.

Fetal macrosomia (FM) is a well-recognized complication of diabetic pregnancy but it is not known whether placental transport mechanisms are altered. We therefore studied the activity of the system A amino acid transporter, the system L amino acid transporter, and the Na+/H+ exchanger in microvillous membrane vesicles from placentas of macrosomic babies born to diabetic women (FM group), from placentas of appropriately grown babies born to diabetic women (appropriate for gestational age group) and from placentas of appropriately grown babies of normal women (control group). Sodium-dependent uptake of [14C]-methylaminoisobutyric acid at 30 s (initial rate, a measure of system A activity) was 49% lower into FM vesicles than into control vesicles (P < 0.02); this effect was due to a decrease in Vmax of the transporter with no change in Km. There was no significant difference in system A activity between the appropriate for gestational age group and control or FM group. There was also no difference between system L transporter or Na+/H+ exchanger activity between the three groups. We conclude that the number of system A transporters per milligram of membrane protein in the placental microvillous membrane is selectively reduced in diabetic pregnancies associated with FM.

Adult↗
PubMed1994

Predicting preterm delivery: the fetal fibronectin test.

Preterm labour and delivery is a major problem and the leading cause of perinatal death in the UK. At present it is virtually impossible for doctors and midwives to predict when preterm labour is about to start. A new test may help with this problem. It detects the presence of fetal fibronectin in the vagina, which may indicate that the cervix is preparing to begin labour. Although these are early days, the fibronectin test looks promising. It is suitable at present for high-risk patients. Further studies are needed before its use can be justified as a screening test for low-risk women.

Female↗
PubMed1993

Inhibition of contractions of the isolated human myometrium by potassium channel openers.

OBJECTIVE: The aim was to investigate the properties of two potassium channel openers in human myometrium. STUDY DESIGN: The abilities of aprikalim and BRL 38227 to inhibit contractions produced by potassium chloride and oxytocin of myometrial strips from nonpregnant and pregnant women were studied. RESULTS: Aprikalim (1 and 10 mumol/L) and BRL 38227 (1 and 10 mumol/L) suppressed contractions induced by low (10 and 20 mmol/L) but not high (40 and 80 mmol/L) potassium chloride concentrations. Aprikalim and BRL 38227 were also potent relaxants of oxytocin (1 nmol/L)-induced contractions with rapid onset of action, of similar potency to each other, and reversible. Both compounds were significantly more potent against oxytocin (1 nmol/L)-induced contractions in myometrial strips from nonpregnant than from pregnant women. Aprikalim and BRL 38227, as relaxants of oxytocin-induced contractions, were antagonized by glibenclamide (1 mumol/L), a blocker of adenosine 5'-triphosphate-sensitive potassium channels. CONCLUSIONS: The results suggest that aprikalim and BRL 38227 relax the human myometrium by potassium channel opening, possibly at adenosine 5'-triphosphate-sensitive potassium channels. Compounds of this pharmacologic class are useful for investigating the physiologic functions of potassium channels in this tissue and could have a place in the treatment of dysmenorrhea and preterm labor.

Benzopyrans↗
PubMed1992

Induction of labour with prostaglandin gel in patients with unfavourable cervices.

151 primigravid patients with Bishop scores of 4 or less were induced with prostaglandin E2 gel using an initial dose of 2 mg followed by 1 mg or 2 mg at 6 hours. Eighty one patients (53.6 per cent) were in established labour or had delivered by 12 hours, and a further 31 (20.5 per cent) had achieved successful ripening of the cervix. Ninety per cent and 64.5 per cent respectively achieved vaginal delivery and although 39 patients failed to respond to this regime, 72 per cent delivered vaginally after augmentation. No case of hypertonus was recorded and only one patient had abdominal delivery for "failed induction". This regime provides an effective means of induction of labour for a difficult group of patients with little worry of overstimulation and low "failed induction" rates.

Administration, Intravaginal↗
PubMed1991

Sodium-dependent magnesium transport across in situ perfused rat placenta.

Placentas of anesthetized rats were perfused in situ on the fetal side to study mechanisms of Mg2+ transport. The perfusate was a Mg(2+)-free Krebs-Ringer, and the unidirectional transfer of Mg2+ from maternal plasma to this Ringer was compared with that of 45Ca and 51Cr-EDTA, the latter being employed as a paracellular diffusional marker. Placental perfusion with amiloride (0.5 mM) or ouabain (1 mM) both rapidly (4 min) reduced maternal-fetal clearance (Kmf) for Mg2+ but had no effect on Kmf for 45Ca. In contrast, perfusion of the carbonic anhydrase inhibitor acetazolamide (1 mM) did not affect Kmf for Mg2+ or 45Ca. Placental perfusion with a Na+-free Ringer reduced Kmf for both Mg2+ and 45Ca, although the latter response was delayed. Kmf for 51Cr-EDTA was increased by amiloride and was unaffected by perfusion of ouabain, acetazolamide, or Na+-free Ringer, indicating that the effects of these treatments on Kmf of Mg2+ do not reflect nonspecific effects on placental permeability. These data suggest that maternal-fetal transfer of Mg2+ across the perfused rat placenta is Na+ dependent.

Acetazolamide↗
PubMed1991

Effects of two synthetic parathyroid hormone-related protein fragments on maternofetal transfer of calcium and magnesium and release of cyclic AMP by the in-situ perfused rat placenta.

Two human parathyroid hormone-related protein (hPTHrP) fragments were tested for effects on maternofetal transfer of 45Ca and Mg across the in-situ perfused rat placenta at 21 days of gestation (term = 23 days). The fetal placental circulation was perfused with a Mg-free Krebs-Ringer solution and the unidirectional maternofetal clearance (Kmf) of 45Ca and Mg compared with that of 51Cr-EDTA, the latter being employed as a paracellular diffusional marker. Placental perfusion with hPTHrP(1-34) (100 ng/ml) or hPTHrP(75-86)amide (50 ng/ml) did not significantly alter the Kmf of 45Ca or that of Mg. In separate rats, however, hPTHrP(1-34) but not hPTHrP(75-86)amide stimulated marked placental cyclic AMP (cAMP) release, the peak response of 63 +/- 7 pmol/min occurring 10 min after the beginning of the peptide perfusion. A lower dose of hPTHrP(1-34) (4 ng/ml) produced a similar peak release of cAMP, as did [Nle8,21, Tyr34]-rPTH(1-34)amide (4 ng/ml) and the adenylate cyclase agonist forskolin (17 mumol/l). Forskolin also rapidly increased the Kmf of 45Ca but not that of Mg or 51Cr-EDTA. The present study indicates that hPTHrP does not acutely affect maternofetal transfer of Ca or Mg across the perfused rat placenta. The data also question the role played by cAMP in the stimulatory actions of forskolin on placental Ca transport.

Animals↗
PubMed1990

Evidence for active maternofetal transfer of magnesium across the in situ perfused rat placenta.

Mechanisms of maternofetal Mg transfer have been investigated across the in situ perfused rat placenta at 21 d gestation (term = 23 d). The fetal placental circulation was perfused with Mg-free Krebs-Ringer solution and clearance of Mg from maternal plasma across the placenta [unidirectional maternofetal clearance (Kmf) Mg] compared with that for 45Ca and 51Cr-EDTA, the latter being used as a diffusional marker. Because diffusion coefficients determined for these solutes were similar (6.8-7.6 X 10(-6) cm2.sec-1), greater Kmf values determined for Mg and 45Ca (mean +/- SD: 26.7 +/- 9.2 and 93.1 +/- 29.8 microL.min-1.g-1 placenta, respectively) compared to 51Cr-EDTA (3.2 +/- 0.9 microL.min-1.g-1) suggest that maternofetal transfer of these cations occurs by mechanisms in addition to diffusion. Kmf Mg was also greater than Kmf 51Cr-EDTA when measured across the dually perfused rat placenta, in which the maternal uterine artery was additionally perfused with Mg-containing (0.5 mmol.L-1) Krebs-Ringer solution. Decreasing the Mg concentration in the maternal perfusate by 90% reduced Mg appearance in the fetal perfusate by 87% within 8 min; this suggests that Kmf Mg across the in situ perfused placenta largely reflects Mg transfer from maternal plasma and not simply elution of a placental Mg pool. Addition of KCN (1 mmol.L-1) to the fetal perfusate or lowering perfusate temperature from 37 to 26 degrees C significantly reduced Kmf Mg and Kmf 45Ca across the in situ perfused placenta. In contrast, Kmf 51Cr-EDTA was increased by KCN and unaffected by temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Maternal pyrexia associated with the use of epidural analgesia in labour.

To establish the effect of pain relief on maternal temperature during labour forty patients who went into spontaneous labour with a single fetus, had a normal temperature (less than 37.5 degrees C), and had no clinical evidence of infection were investigated prospectively. They were divided into two comparable groups--one receiving pethidine and the other epidural analgesia. Both groups had much the same temperatures at the beginning of labour and before any analgesic administration. The mean temperature in the pethidine group remained constant during labour, whereas in the epidural analgesia group it showed a significant rise after only 6 hours of labour. This rise was not related to any clinical evidence of infection. Patients receiving epidural analgesia during labour are at increased risk of developing pyrexia. This pyrexia may be the result of vascular and thermoregulatory modifications induced by epidural analgesia.

Adult↗