Dichotomization of continuous measurements using generalized additive modelling--application in predicting intrapartum caesarean delivery

In prediction model development, continuous variables are often dichotomized at empirically chosen thresholds to simplify calculations and facilitate decision making. However, these choices are often made in the absence of estimated covariate effects and may be inaccurate, thus weakening the models. To improve this approach, generalized additive modelling that allows non-parametric estimation of the true covariate effects is used for threshold selection. In this study, this approach is illustrated by development of prediction models for intrapartum Caesarean deliveries. The prediction performance of the models thus developed is significantly better than that developed using empirically chosen thresholds for dichotomization.

Fetal and maternal levels of lipid peroxides in term pregnancies

OBJECTIVE

To examine the relationships between maternal and fetal concentrations of lipid peroxides in term pregnancies before the onset of labor.

METHODS

Umbilical cord arterial and venous blood samples were collected from 114 singleton term pregnancies delivered by elective cesarean section. Base excess, oxygen, carbon dioxide and pH were measured in both samples and compared to identify double venous samples. Maternal venous and umbilical cord arterial and venous concentrations of organic hydroperoxides and malondialdehyde were assayed.

RESULTS

Maternal plasma malondialdehyde was, on average, double that of cord blood, whereas maternal organic hydroperoxide was only 18% higher. Maternal organic hydroperoxide was correlated with cord arterial and venous levels of organic hydroperoxide but not with pH, carbon dioxide, oxygen or base excess. Maternal malondialdehyde concentration was significantly correlated with both umbilical arterial and venous values of malondialdehyde and with arterial oxygen. Multiple regression shows that 70% of the variation in maternal malondialdehyde can be accounted for by variation in arterial and venous malondialdehyde, and arterial oxygen and base excess. A similar regression analysis with maternal organic hydroperoxide as dependant variable incorporated only umbilical arterial organic hydroperoxide concentration.

CONCLUSION

These findings suggest that there is significant trans-placental transport of malondialdehyde from the fetal circulation.

Sequential assignment of 1H, 15N, 13C resonances and secondary structure of human calmodulin-like protein determined by NMR spectroscopy

Human calmodulin-like protein (CLP) is closely related to vertebrate calmodulin, yet its unique cell specific expression pattern, overlapping but divergent biochemical properties, and specific target proteins suggest that it is not an isoform of calmodulin. To gain insight into the structural differences that may underlie the difference target specificities and biochemical properties of CLP when compared to calmodulin, we determined the sequential backbone assignment and associated secondary structure of 144 out of the 148 residues of Ca2+-CLP by using multinuclear multidimensional NMR spectroscopy. Despite a very high overall degree of structural similarity between CLP and calmodulin, a number of significant differences were found mainly in the length of alpha-helices and in the central nonhelical flexible region. Interestingly, the regions of greatest primary sequence divergence between CLP and calmodulin in helices III and VIII displayed only minor secondary structure differences. The data suggest that the distinct differences in target specificity and biochemical properties of CLP and calmodulin result from the sum of several minor structural and side-chain changes spread over multiple domains in these proteins.

The use of continuous monitoring blood culture systems in the diagnosis of catheter related sepsis

AIM

To assess whether the information provided by automated continuous monitoring blood culture systems could aid in the diagnosis of catheter related sepsis.

METHODS

Serial dilutions of a strain of coagulase negative staphylococcus were inoculated into the BacT/Alert blood culture system. Blood culture results for seven patients with possible catheter related sepsis from coagulase negative staphylococci were reviewed.

RESULTS

Time to positivity and length of lag period were strongly related to the concentration of bacteria inoculated (average decrease of 1.5 hours to positivity for each 10-fold increase in concentration). Time to positivity and length of lag period were significantly shorter for central line blood cultures than for those taken from peripheral sites.

CONCLUSIONS

Using data already measured by continuous monitoring blood culture systems may provide a simple alternative to quantitative blood cultures for the diagnosis of catheter related sepsis.

Metabolic and inflammatory responses after laparoscopic and abdominal hysterectomy

OBJECTIVE

Our purpose was to quantify and compare the metabolic and inflammatory changes after laparoscopic and abdominal hysterectomy.

STUDY DESIGN

Forty-four patients with no major medical disease requiring abdominal hysterectomy for benign disorders were randomly assigned to have laparoscopic hysterectomy (n = 20) and abdominal hysterectomy (n = 24). Venous blood and 24-hour urine samples were collected the day before and for each of the first 3 postoperative days.

RESULTS

No differences were present in demographic characteristics, operating time, and uterine weight between the two groups. No major complications were encountered. The laparoscopic hysterectomy group had a significantly lower postoperative morphine consumption (median 5.5 vs 14 mg, P < .05), lower febrile morbidity rate (15% vs 45.8%, P < .05), and shorter hospital stay (median 4 vs 6 days, P < .001) and demonstrated a less intense stress response in terms of serum interleukin-6 (median 50.6 vs 73.9 pg/mL x hour x 10, P = .01), C-reactive protein (median 28.1 vs 44.7 mg/L x hour x 10(2), P = .005), cortisol (median 23.4 vs 27.2 mg/mL x hour x 10(3), P = .04), white blood cell count (median 59.5 vs 69.8 10(9)/L x hour x 10, P = .009), 24-hour urinary excretion of cortisol (median 34.8 vs 44.2 nmol/L x hour x 10(3), P = .02), and norepinephrine (median 80.8 vs 132.4 nmol/L x hour x 10(2), P = .001). No significant difference was detected in plasma glucose (median 41.5 vs 45.6 mmol/L x hour x 10, P = 6) and 24-hour urinary excretion of epinephrine (median 32.2 vs 34.1 nmol/L x hour x 10(2), P = .3).

CONCLUSION

Laparoscopic hysterectomy is associated with a lower morbidity and a less intense stress response than abdominal hysterectomy for benign diseases.

Lipid peroxidation in cord blood at birth: the effect of labour

OBJECTIVE

To determine the effect of labour on free oxygen radical activity in the fetus, as reflected by lipid peroxide levels in umbilical cord arterial blood.

DESIGN

Prospective, observational study.

SETTING

Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong.

METHODS

Umbilical cord arterial and venous blood samples were collected from singleton term infants delivered by elective caesarean section. Base excess, PO2, pCO2 and pH were measured in both samples and compared to identify double venous samples. Cord arterial acid-base balance and concentrations of organic hydroperoxides and malondialdehyde were compared with those obtained from normal vaginal deliveries.

RESULTS

Cord arterial blood samples, obtained from cases of uncomplicated labour followed by spontaneous vaginal delivery, had significantly higher lipid peroxide concentrations than those delivered following elective caesarean section. This was most marked for malondialdehyde with a median value increased by 105%, whilst organic hydroperoxide was increased by only 27%. Of the acid-base parameters, base excess was increased by 78%, with only minimal changes in pH, pCO2 and PO2. These differences remained highly significant after including other pregnancy characteristics in multivariate analysis.

CONCLUSION

The findings indicate that high levels of free oxygen radical activity in the fetus are a function of the labour process, as are changes in acid-base balance.

Developing the Cambridge palliative audit schedule (CAMPAS): a palliative care audit for primary health care teams

BACKGROUND

Problems with the provision of palliative care have been reported. Audit is one means of improving care. Earlier audits of primary care palliative care have been initiated by general practitioners (GPs) and are predominantly retrospective record reviews. Widely applicable methods for the audit of primary care palliative care do not exist.

AIM

To develop relevant palliative care standards and to devise an audit schedule (the Cambridge palliative audit schedule, CAMPAS) suitable for monitoring palliative care in diverse primary care settings.

METHOD

Primary health care team (PHCT) members collaborated at all stages. Reasonable outcomes and acceptable interventions for PHCTs were identified and standards developed. Each standard was constructed to ensure uniform interpretation, and CAMPAS was structured to collect data necessary for determining whether the standards were met.

RESULTS

Over 50% of PHCTs (n = 20) in the health district were recruited and trained to use CAMPAS. A total of 876 contacts with 29 patients was recorded by PHCTs using CAMPAS. Considerable inter- and intra-PHCT variation was found in the achievement of the standards.

CONCLUSIONS

The favourable participation rate suggests commitment to audit and improvement in patient care. Overall, the standards were reported to be suitable. Although 100% achievement of some standards may be unrealistic, the level of attainment for many suggests that it is possible. CAMPAS has been reported to be a useful structure for recording assessments and monitoring care, as well as a usable audit schedule. As an audit tool, it identified areas in need of improvement and facilitated feed-back to participants. Future audit is required to determine whether improvements in care have been effected.

Racial variation in incidence of trisomy 21: survey of 57,742 Chinese deliveries

The objective of this study was to establish whether the influence of advanced maternal age on the incidence of trisomy 21 in the local Chinese population is similar to that seen among European patients by comparing the observed number of trisomy 21 cases against the expected number which was calculated from age-specific Caucasian data and adjusted for intrauterine lethality and rate of amniocentesis. The obstetric and neonatal data of 57,742 pregnancies in ethnic Chinese were reviewed, of which 10.5% were from mothers age 35 or over. A total of 74 cases of trisomy 21 was detected (overall incidence of 1.28 per 1,000 deliveries). The expected number of trisomy 21 cases in mothers younger than 35 was 45.6, which was similar to the observed number of 43. Among mothers age 35 or above, the expected and observed numbers of cases were 38.52 and 31, respectively, again a difference not statistically significant. Therefore we conclude that there is no significant racial variation in the incidence of trisomy 21, both in the younger and older age groups, when comparing Chinese to Caucasian populations.

Lipid peroxidation in cord blood at birth: a marker of fetal hypoxia during labour

OBJECTIVE

This prospective study examined purine metabolism in relation to free oxygen radical activity, as reflected by lipid peroxide levels in umbilical cord blood at birth.

SETTING

Departments of Obstetrics and Gynaecology and of Chemical Pathology, the Chinese University of Hong Kong, Hong Kong, and Purine Research Laboratory, UMDS of Guy's and St. Thomas' Hospitals, London, UK.

METHODS

Umbilical cord arterial and venous blood samples were collected from 132 singleton term deliveries for determination of hypoxanthine, xanthine, inosine, uric acid, organic hydroperoxides (OHP) and malondialdehyde. Oxygen saturation, PO2, pCO2, pH, and base excess (BE) were also measured.

RESULTS

There was a significant correlation between umbilical arterial and venous levels of hypoxanthine, xanthine, inosine, uric acid and all acid-base parameters (p < 0.001). Significant arteriovenous differences were observed for all parameters with the exception of inosine, uric acid and OHP. Umbilical arterial xanthine and potassium correlated significantly with OHP, but hypoxanthine, inosine and uric acid did not. In 13 babies classified as severely asphyxiated at birth (umbilical arterial pH <7.15, BE <-8), xanthine and OHP levels were significantly elevated when compared with non-asphyxiated babies. No significant differences were observed for hypoxanthine, inosine or uric acid.

CONCLUSION

The findings indicate that OHP, either in cord arterial or venous blood, is the best marker of free oxygen radical activity in the fetus, and that this correlates with other evidence of cellular hypoxia-reperfusion injury. We propose OHP is a better measure of perinatal outcome than either acid-base balance or hypoxanthine.

Application of a chimeric green fluorescent protein to study protein-protein interactions

The green fluorescent protein (GFP) of the jellyfish Aequorea victoria is an emerging tool to monitor gene expression in situ and in vivo. Because of its fluorescence properties, when GFP is fused in-frame to a specific protein of interest, various aspects of the behavior of this protein can be analyzed noninvasively. Here we describe a fusion between GFP and human calmodulin-like protein (CLP) and show that this protein retains fluorescence and known characteristics of CLP, including Ca(2+)-dependent interaction with phenyl-Sepharose and interaction with a specific cellular target protein. The results suggest a novel application for GFP fusion proteins in the rapid, nonradioactive detection of interacting proteins on gel overlays.

The implementation of external cephalic version at term for singleton breech presentation--how can we further increase its impact?

The overall incidence of breech presentation at delivery remained at 2 to 3% in a unit where external cephalic version (ECV) was the preferred treatment option for term singleton breech presentation. The objective of this study was to investigate which factors accounted for this high residual incidence, so that the impact of ECV could be further increased. All breech deliveries and ECVs over a 1-year period in a teaching hospital are reviewed. The incidence of term singleton breech delivery was 1.96% among 7,702 total deliveries. There were 115 patients counselled for ECV, of which 15.7% declined the offer and 4.1% went into labour before their scheduled ECV. Among the 93 ECVs performed, 74 were successful and 56 delivered vaginally in cephalic presentation. ECV was not performed in 131 cases. The major reasons were patients' refusal (13.7%), breech first diagnosed in labour or after rupture of membranes (44.3%), oligohydramnios or growth retardation (9.9%) and previous Caesarean section (8.4%). Only 5 patients were not counselled for ECV in the absence of contraindications. The practice of ECV reduced the overall Caesarean section rate by 0.65%, or 4.3% of the total number of Caesarean sections. In conclusion, ECV at term definitely reduces the Caesarean section rate. However, it is unlikely that the overall Caesarean section rate could be reduced by more than 1% even with 100% uptake of ECV unless the use of ECV is to be extended to those with prior Caesarean section, ruptured membranes, oligohydramnios, growth retardation or those who are in labour.

Lipid peroxidation in cord blood: a randomised sequential pairs study of prophylactic saline amnioinfusion for intrapartum oligohydramnios

OBJECTIVE

To determine the efficacy of prophylactic intrapartum amnioinfusion in reducing cord arterial lipid peroxide levels in cases of intrapartum oligohydramnios.

DESIGN

Sequential randomised pairs trial.

SETTING

Delivery suite of a teaching hospital, the Chinese University of Hong Kong.

POPULATION

Women with singleton, term pregnancy, cephalic presentation, clear amniotic fluid and an amniotic fluid index < or = 5 cm, with a normal intrapartum fetal heart rate tracing within 30 minutes of amniotomy.

METHODS

Selected patients were randomised either for prophylactic saline amnioinfusion or as control cases. Cord arterial lipid peroxide concentrations and acid base balance were determined at delivery.

MAIN OUTCOME MEASURES

Operative intervention for fetal distress, cord arterial malondialdehyde and organic hydroperoxide levels, pH and base excess.

RESULTS

Amnioinfusion was associated with significant reductions in the incidence of operative delivery for fetal distress and in lipid peroxide levels, an increase in base excess, but no significant alteration in pH.

CONCLUSIONS

Oligohydramnios in labour is associated with high levels of lipid peroxidation, reflecting cellular damage by release of free radicals following hypoxia reperfusion. Prophylactic intrapartum saline amnioinfusion is an effective technique for the reduction of lipid peroxidation and of the incidence of operative intervention for fetal distress but has no significant effect on overall operative delivery rates.

Pregnancy outcome beyond 41 weeks gestation

OBJECTIVE

To determine maternal and perinatal morbidity and the spontaneous labor rate beyond 41 weeks of gestation.

METHOD

Patients with uncomplicated pregnancy were recruited at 41 weeks and screened for fetal or maternal well-being. Following observation between 41 and 42 weeks, patients were randomized to either serial monitoring by cardiotocography and measurement of amniotic fluid index, or to immediate induction. Comparisons were made using the chi(2) test. Results after 42 weeks were analyzed according to intention at randomization.

RESULTS

Morbidity was not increased before 42 weeks. After 42 weeks, the cesarean section rate and incidence of meconium below the vocal cords were increased in monitored patients. The median gestational age in patients who were monitored was 298.5 (294-321) days. In patients observed from 41 weeks, 91.6% labored spontaneously.

CONCLUSION

It is reasonable to observe uncomplicated pregnancy until 42 weeks with adequate monitoring. After 42 weeks, induction of labor is preferred.

Lipid peroxidation in cord blood: the effect of amniotic fluid volume

OBJECTIVE

To assess the effect of amniotic fluid volume on umbilical cord arterial lipid peroxide levels in relation to intrapartum events.

DESIGN

Prospective observational study.

SETTING

Delivery suite of a teaching hospital, the Chinese University of Hong Kong.

POPULATION

Women with singleton, term, cephalic presentation, and an initially normal fetal heart rate tracing.

METHODS

All pregnancies had amniotic fluid index assessments before and after amniotomy and cord arterial lipid peroxide determination at delivery. Multiple regression analysis.

MAIN OUTCOME MEASURES

Cord arterial malondialdehyde and organic hydroperoxide levels.

RESULTS

In 247 cases following amniotomy levels were inversely correlated with intrapartum amniotic fluid index. Amniotic fluid index during labour was an independent determinant of cord arterial lipid peroxide concentration, along with duration of second stage, absence of epidural, presence of tight nuchal cord entanglement and evidence of fetal distress.

CONCLUSIONS

Oligohydramnios during labour is associated with high levels of lipid peroxidation in the fetus, reflecting an increase in hypoxic cellular damage by free radicals.

Oxygen free radical activity in the second stage of labor

OBJECTIVE

To assess fetal cellular injury arising from oxygen free radical activity in relation to the duration of the second stage of labor.

PATIENTS AND METHODS

Cord arterial pH, malondialdehyde and organic hydroperoxides levels were determined following vaginal delivery of 326 term singleton pregnancies. Of these, 35 (11%) received epidural analgesia. The length of the second stage was recorded from the time of full dilatation to delivery.

RESULTS

Arterial cord pH, malondialdehyde and organic hydroperoxides were significantly correlated with duration of second stage of labor (r=-0.4492; r=0.2542; r=0.2244; respectively, p<0.001). The association of lipid peroxidation products with second stage duration was independent of cord pH. This correlation was unchanged when cases of operative delivery were excluded. However, the relationship lost statistical significance amongst cases who received epidurals.

CONCLUSIONS

The duration of the second stage is correlated with raised reactive oxygen species-derived lipid peroxidation products. Caution should be exercised in the management of prolonged second stage of labor.

Ten years experience of caesarean and postpartum hysterectomy in a teaching hospital in Hong Kong

OBJECTIVE

To review 10 years' experience of obstetric hysterectomy in a university teaching hospital.

STUDY DESIGN

A retrospective study of all cases of caesarean or postpartum hysterectomy between 1984-1994. Demographic data and clinical details including indications for operation, nature of surgical management and complications were analysed.

RESULTS

The incidence of obstetric hysterectomy was 1 in 1420 deliveries. Overall, 0.32% of caesarean sections and 0.02% of vaginal deliveries were complicated by emergency obstetric hysterectomy. Morbidly adherent placenta (32.7%) was the most common cause of uncontrollable haemorrhage. Prior caesarean delivery and placenta praevia were the main risk factors for its development. Operative complications included intra-operative hypotension (33.3%), urinary tract injury (22.2%) and re-exploration for persistent haemorrhage (12.5%). There was one maternal death due to suspected air embolism.

CONCLUSIONS

Emergency obstetric hysterectomy, though uncommon, remains a potentially life-saving procedure which every obstetrician must be familiar with. It is extremely important to have early surgical intervention, prompt resuscitation and management by experienced medical staff to minimise morbidity and mortality.

Predictors of successful external cephalic version at term: a prospective study

OBJECTIVE

To investigate clinical and ultrasonographic predictors of outcome of external cephalic version at term.

DESIGN

Prospective observational study.

SETTING

University obstetric unit.

POPULATION

All external cephalic versions performed over two years (n = 243).

METHODS

Nineteen different clinical and ultrasonographic variables were recorded before each procedure. The ability of each of the 19 variables to predict the success or failure of external cephalic version was assessed by univariate analysis. The study population was then divided into two subgroups of 129 and 114 patients by random allocation using computer generated numbers. Logistic regression was performed in each subgroup to assess the relative importance and independence of the important variables. The derived regression models were then applied to the other subgroup of patients to assess accuracy and reproducibility.

RESULTS

The overall success rate of the procedure was 69.5%. Both regression models identified the same three variables as independent predictors of failed versions: 1. presenting part engaged; 2. difficult to palpate the fetal head, and 3. a tense uterus on palpation. The two models correctly predicted 75.2% and 84.2% of outcomes in the other subgroup. If uterine tone, which was assessed after administration of tocolytic, was excluded from the analysis, the other two factors remained in the models, with the addition of nulliparity as a significant predictor of failed external cephalic version. The chance of success of external cephalic version in the original 243 women was found to be < 20% if two of these variables were present, 0% if all three were present, and 94% if none were present.

CONCLUSIONS

The outcome of external cephalic version can be predicted by easily available clinical parameters.

A study on prophylactic antibiotics in cesarean sections--is it worthwhile?

BACKGROUND

To study the effect of single-dose prophylactic Augmentin on patients undergoing cesarean section.

METHODS AND MATERIAL

Three hundred and twenty women undergoing cesarean section were randomized into two groups in a prospective, double-blind, placebo-controlled study. One hundred and sixty women were allocated to receive a single-dose of 1.2 g Augmentin at induction of anesthesia and 160 were allocated to a control group who received placebo. The following post-cesarean outcome parameters were compared between the two groups: duration of hospital stay, febrile morbidity, urine microscopy, bacteriuria, endometritis, and wound infection.

RESULTS

There was no significant difference between the two groups with respect to the duration of post-operative hospital stay or the incidence of febrile morbidity, endometritis, and wound infection. However, the study group had fewer post-operative abnormalities in urine microscopy (p < 0.05) and bacteriuria (p < 0.01). The bacterial flora were also different between the two groups.

CONCLUSION

Single-dose prophylactic Augmentin did not produce any clinically significant improvement in the post-operative course of patients undergoing cesarean section. If proper surgical techniques are followed in association with closed rectus sheath drainage, it is unlikely that any trial of antibiotics will be able to demonstrate any clinically significant outcome.

A randomized prospective study of laparoscopy and laparotomy in the management of benign ovarian masses

OBJECTIVE

Our purpose was to compare the results of laparoscopy with laparotomy in the management of ovarian masses not suspected to be malignant.

STUDY DESIGN

In a prospective randomized study 102 patients requiring surgical management of ovarian masses were randomly assigned to laparoscopy (52) or laparotomy (50) in a teaching hospital from July 1994 to September 1995. Inclusion criteria was tumor not suspected to be malignant with a diameter of < or = 10 cm as measured by ultrasonography. All operations were performed by trainees under the supervision of an experienced surgeon. Statistical analysis included t tests and chi2 tests.

RESULTS

There were no differences in demographic characteristics between the two groups nor any difference in the size of ovarian masses, adnexal adhesion score, or frequency of bilateral disease. All the ovarian masses were benign. Endometriotic cysts and dermoid cysts were the most common disorder in the two groups. Cystectomy was performed in > 70% of cases in each group. Operating time was not increased with the laparoscopic approach, and the frequency of inadvertent rupture of the ovarian masses was just as high as in laparotomy. The laparoscopic approach was associated with a significant reduction in operative morbidity (odds ratio 0.34, 95% confidence interval 0.13 to 0.88), postoperative pain and analgesic requirement, hospital stay, and recovery period. Patients in general were satisfied with the operation, but significantly more patients were satisfied with the laparoscopy scar.

CONCLUSION

Operative laparoscopy should replace laparotomy in the management of benign ovarian masses.

A review of laparoscopy and laparotomy in the management of tubal pregnancy

A retrospective review was performed of all women who had undergone operation for a tubal pregnancy at the Prince of Wales Hospital, Hong Kong, from November 1992 to March 1994. One hundred and five patients were included---61 were managed by laparoscopy and 44 by laparotomy. There were no differences in age, parity, gestational age, frequency of previous ectopic pregnancy, or laparotomy between the two groups. Sixty per cent of patients in the laparotomy group had a diagnostic laparoscopy prior to the laparotomy. The laparoscopy group had a lower incidence of haemoperitoneum (45.9% vs 75.0%, P<0.05). There was no difference in the mean operating time. The laparoscopic approach was associated with a significant reduction in: intra-operative blood loss (46.7plus minus76.8 mL vs 213.4plus minus149.3 mL. P<0.001), post-operative analgesia requirement (odds ratio 0.08, 95% CI, 0.02-0.32), post-operative morbidity (odds ratio 0.27, 95% CI, 0.12-0.58), length of hospital stay (2.9plus minus2.2 days vs 5.1plus minus1.2days, P<0.001) and recuperation period (11.0plus minus9.3days vs 21.7plus minus8.5 days, P<0.001). Operative laparoscopy has the advantage of combining diagnostic and therapeutic procedures in a single operation, and is a better approach than laparotomy in the management of tubal pregnancy.

Are Hong Kong babies getting bigger?

OBJECTIVE

To establish recent birth weight trends in Hong Kong.

METHOD

A total of 10,512 confinements for the years 1985-86, and 7857 for the years 1995-96 were analyzed.

RESULT

There was a significant increase in maternal height, weight at booking, and maternal age, whereas the body-mass index was reduced slightly (P < 0.0001). Parity increased significantly, with the percentage of parous women rising from 44.1% to 55.6% (P < 0.0001). The percentage of female infants decreased from 49.5% to 47.9%. Despite these changes there was no significant difference in mean birth weights between the two groups. When birth weight was controlled for sex, parity, maternal height and weight there was a trivial increase of 15 g over time (P = 0.01).

CONCLUSION

Birth weight has reached a plateau in Hong Kong despite a continuing increase in the regions' socioeconomic status, and evidence of improved nutritional well-being.

The treatment of cervical intra-epithelial neoplasia: when could we 'see and loop'

OBJECTIVE

To determine the possible role of the selective 'see and loop' approach with a loop electrosurgical excision procedure (LEEP) for high grade cervical intra-epithelial neoplasia (CIN).

DESIGN

Comparison of the colposcopic and histological diagnosis in patients who received LEEP treatment.

SUBJECTS

Subjects included 95 patients from May to October 1994.

SETTING

Department of Obstetrics and Gynaecology, the Prince of Wales Hospital, the Chinese University of Hong Kong.

MAIN OUTCOME MEASURES

Agreement between colposcopic and histological diagnosis and between histological diagnosis by biopsy and by LEEP. Sensitivity and false positive rate of colposcopic diagnosis in different classifications of high grade CIN lesions. Decision analysis on the cost of three proposed strategies based on the study results.

RESULTS

The colposcopic diagnosis was correct in 58% of cases with 31% overall and 11% undercall rates. The false positive rate of colposcopic examination was 11.4% in the diagnosis of CIN III or more advanced lesions and 36.8% if CIN II lesions are also classified as high grade. Decision analysis showed a saving of: (i) US$53,000: or (ii) US$73,000 per annum if 'see and loop' was performed on all cases where colposcopic diagnosis is: (i) CIN III or more; or (ii) CIN II or more. If the cost of inappropriate surgery by LEEP is estimated to be more than US$550 per person over-treated (i) becomes the preferred strategy.

CONCLUSIONS

Selective 'see and loop' approach for high grade CIN III lesions suspected on colposcopy will not over-treat significantly but will reduce the number of colposcopy appointments, waiting list for colposcopy and subsequent expenses.

Lipid peroxidation in cord blood: the effects of umbilical nuchal cord

OBJECTIVE

To examine the relation between cord entanglement around the fetal neck and umbilical arterial measures of free oxygen radical activity at birth.

DESIGN

Prospective observational study of the lipid peroxide levels in umbilical cord arterial blood.

SETTING

Delivery suite of Prince of Wales Hospital, Hong Kong.

POPULATION

Women with a singleton pregnancy, at term (37 to 42 weeks of gestation), cephalic presentation, spontaneous or induced labour and an initially normal fetal heart rate tracing.

METHODS

A series of 230 singleton deliveries had determination of two lipoperoxides in umbilical arterial cord blood: malondialdehyde and organic hydroperoxide. Umbilical pH, PO2, PCO2 and base excess were also measured in both umbilical cord arterial and venous blood.

MAIN OUTCOME MEASURES

Umbilical cord blood gases and arterial malondialdehyde and organic hydroperoxide levels.

RESULTS

Forty-nine cases of nuchal cord were observed: 14 tight and 35 loose. Tight nuchal cord was associated with a low 1-min Apgar score and increased lipid peroxide levels. Loose nuchal cord was associated with larger amniotic fluid volume and significantly decreased lipid peroxide levels.

CONCLUSIONS

This study suggests that tight nuchal cord is associated with increased free oxygen radical activity in the fetus, but that loose nuchal cord carries no adverse effects.

Dietary patterns amongst ethnic Chinese pregnant women in Hong Kong

OBJECTIVE

To provide baseline data on the food consumption pattern of ethnic Chinese women in Hong Kong during pregnancy, in order to identify any risk of nutritional imbalance in this population.

SUBJECTS AND OUTCOME MEASURES

One hundred and sixty-seven primagravid ethnic Chinese women attending the antenatal booking clinic at the Prince of Wales Hospital in the New Territories region were recruited. Among the study sample, subjects with less than 7 years of residence in Hong Kong were identified as recent immigrants (n = 25), while the remainder (n = 142) were classified as local. Half of the recent immigrants originated on the Chinese mainland and half from Indonesia. The eating patterns of the entire sample were compared with intake recommended in the Taiwan Food Guide. Comparisons were made between local and immigrant regarding age, educational standard and consumption of food from each food group.

RESULTS

The median intake of meat and meat substitutes was significantly higher than recommendation. There was no significant difference between actual and recommended intake of fruit but the consumption of dairy products, bread and cereals, and vegetables were all significantly below minimum recommendation.

CONCLUSION

The unfavorable dietary pattern reflected that many Chinese pregnant women are still not aware of dietary guidelines and the necessity of modifying their dietary practices in order to achieve the optimal maternal nutrition status. This lack of awareness is more prominently exhibited among the Asian Chinese immigrants.

C-myc mutation detected by polymerase chain reaction--heteroduplex in cervical cancer

To evaluate both the incidence of c-myc gene mutation and the relationship of this finding to the clinico-pathologic characteristics of patients with cervical cancer, a polymerase chain reaction (PCR)-based heteroduplex gel electrophoresis method was used to screen DNA extracted from 102 cervical invasive carcinomas referred to the Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong. C-myc mutation was detected and then characterised by sequencing of PCR products in 4 cases (4%). The incidence of c-myc mutation in patients with advanced stage tumours (stage III-IV, 11% was statistically higher than in those with early stages (stage I-II, 1%, p = 0.05). There was also a significant difference in the incidence of c-myc mutation among the patients who had died of their disease (10%), were alive with evidence of disease (25%), and those without evidence of disease (0%, p = 0.0003). These findings indicate that the c-myc mutation is not common in cervical cancer, but where it exists, it may be associated with cancer progression and poorer outcome. Whether the c-myc mutation is an adjunct prognostic indicator in cervical cancer remains to be established in a larger study.

Amnioinfusion for the prevention of meconium aspiration during labour

The aim of this observational study is to review the outcome of prophylactic intrapartum amnioinfusion (AI) in pregnancies complicated by moderate to thick meconium-stained liquor (MSL). The labour and neonatal outcome of all 298 AIs performed over a 3-year period were compared to a matched-control group of patients whose labour was complicated by moderate or thick MSL but without AI. The incidence of moderate or thick meconium below the vocal cords of the neonate were significantly lower in the AI group (6.4% and 3.4%) compared with the control group (15.4% and 6.7%). The incidence of meconium aspiration syndrome in the AI group was half (1.7%) that of the control group (3.7%), although the difference did not reach statistical significance. There was a significant higher incidence of cardiotocographic abnormalities in the AI group (30.5% versus 14.7%), with higher incidences of Caesarean section and operative vaginal deliveries. The reduction in the incidence and thickness of meconium after AI was not accompanied by any statistically significant reduction in adverse fetal outcomes such as low Apgar scores, cord pH values, admissions to and duration of admission to the neonatal unit, or the incidence of meconium-aspiration syndrome.

Vaccination of the badger (Meles meles) against Mycobacterium bovis

This review summarizes current knowledge relating to the potential development of a vaccine against Mycobacterium bovis (M. bovis) for use in badgers. The serious economic loss incurred from bovine tuberculosis in Ireland is highlighted. The problems presented to national bovine tuberculosis eradication programmes by wildlife reservoirs of M bovis, in particular the badger and the brushtail possum, are outlined. Badger and possum ecology and the epidemiology of M. bovis infection in these species are compared in relation to control strategies. Current information regarding the immune responses of badgers and possums to M. bovis infection is presented. Vaccine types, carrier and adjuvant systems, available vaccines for human and animal tuberculosis and delivery to wildlife species are described. The feasibility of vaccinating badgers against M. bovis infection and the possible options for a vaccination strategy are discussed.

Is laparoscopically-assisted vaginal hysterectomy associated with low operative morbidity?

Seventy-one consecutive patients undergoing laparoscopically-assisted vaginal hysterectomy were prospectively evaluated with particular emphasis on the operative morbidity. Bipolar desiccation was the mainstay for haemostasis. Fibroids accounted for two-thirds of the uterine pathology and the average uterine weight was 238.0 g (SD 134.6). Mean operating time was 126.3 minutes (SD 36.9) and decreased with experience despite the progressive increase in uterine weight. The mean blood loss was 432 mL (SD 288) with a mean haemoglobin change of 2.3 g/dL (SD 1.5). Intraoperative complications occurred in 5 patients (7.0%), 2 with inferior epigastric artery injuries and 3 serosal bladder injuries. Postoperative complications occurred in 45 patients (63.4%). Febrile morbidity was the major complication and occurred some 50% of patients, 45% of whom had no underlying cause identified. Vault haematoma was the second most common complication and occurred in 31.0%. The mean hospital stay was 5.4 days (SD 2.7) and the readmission rate was 10%. Our results of laparoscopically-assisted vaginal hysterectomy did not conform with the benefits of reduced blood loss, shorter hospital stay and reduced postoperative complications reported in the literature. The true complication rate of laparoscopically-assisted vaginal hysterectomy should be carefully assessed before this can be considered as the approach of choice to hysterectomy.

A comparison of laparotomy and laparoscopy in the management of ovarian masses

To compare the results of laparoscopy with laparotomy in the management of ovarian masses not suspected of being malignant, a retrospective review was made of 115 patients with ovarian masses operated on, 50 by laparotomy and 65 by laparoscopy, in the Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Hong Kong, from November 1, 1992, to October 31, 1993. In the laparoscopy group, the average size of the ovarian masses was smaller, and there was a significant reduction in the intraoperative blood loss, postoperative analgesic requirement, morbidity (particularly febrile morbidity and urinary retention), length of hospital stay, and recuperation period. The incidence of rupture of the ovarian mass was not related to the operative approach but to the underlying pathology. Two patients in the laparoscopy group were converted to laparotomy, and 1 in the laparotomy group required a second laparotomy. The operating time was longer in the laparoscopic approach, but this could be reduced with experience and improved technique in specimen removal. Laparoscopy appears to be a better approach than laparotomy in the management of ovarian masses where malignancy is not suspected and a competent surgeon is available.

Platelet angiotensin II receptor status during pregnancy in Chinese women at high-risk of developing pregnancy-induced hypertension

OBJECTIVES

The aims of this prospective study were to explore the changes in platelet angiotensin II (A-II) binding in pregnancy amongst Chinese women at high risk of developing pregnancy-induced hypertension (PIH) and the effects of low-dose aspirin and calcium supplementation on A-II binding.

METHODS

Platelet A-II binding was assayed in 15 non-pregnant women and in 63 pregnant women determined to be at risk of PIH on the basis of 2nd-trimester mean arterial pressure (MAP). The pregnant patients were randomized into three groups: control, low-dose aspirin, and calcium supplementation. A-II binding was assayed again during the 3rd trimester in half the women and 8 weeks after delivery.

RESULTS

A-II binding was negatively correlated with MAP measured in the left lateral position (p < 0.05) but not with MAP measured in the supine position. There were no significant differences between A-II binding in non-pregnant and pregnant women. Neither low-dose aspirin nor calcium supplementation caused significant reductions in A-II binding.

CONCLUSION

The measurement of platelet A-II binding is unlikely to provide significant information regarding the risk of PIH over and above that obtained from measurement of 2nd-trimester MAP.

Lipid peroxidation in cord blood at birth

OBJECTIVE

The purpose of this study was to determine oxygen free radical activity in the neonate at birth and relate it to umbilical cord blood acid-base status.

STUDY DESIGN

A series of 110 singleton deliveries had determination of two lipoperoxides in umbilical cord blood: malondialdehyde and organic hydroperoxide. Umbilical pH, PO2, PCO2, bicarbonate, and base excess were also measured.

RESULTS

There was a significant association between lipoperoxides and cord blood pH and base excess. A significant difference existed in the levels of umbilical artery lipoperoxides between nonacidemic and acidemic fetus, as defined by an umbilical arterial pH < 7.20.

CONCLUSION

There is a positive association between lipoperoxide production and acid-base balance at delivery.

Immunocytochemical localization of renin in the developing ovine fetus

The ontogeny of renin distribution in the outer cortical segments was studied by immunocytochemistry in two groups of ovine fetal kidneys; one set of fetal kidneys was obtained at 104-106 days (0.73 gestation, n = 6), and the other at 138-140 days (0.96 gestation, n = 6). Similar studies were performed in kidneys obtained from a lamb (2 weeks old) and from non-pregnant adult sheep, n = 4. Using rabbit anti-mouse renin antiserum that was proven to cross react with sheep renin and 0.033% 3',3'-diamino benzidine tetrachloride as a chromogen, immunoreactivity was found to be localized in the classical juxtaglomerular apparatus and the afferent arteriole in the immature fetuses, newborn lamb and adult sheep. In the mature fetuses a more extensive distribution was noted. Immunoreactivity was found in the afferent arteriole and the juxtaglomerular apparatus as well as other segments of the arterial vascular tree. These findings suggest that renal renin distribution in the lamb fetus is developmentally regulated. The results also correlate well with reports about renal cortical renin content and plasma renin activity at the stages studied. These observations further support the hypothesis that increased renal renin expression occurs in the fetus just prior to birth.

Second and early third trimester atrial natriuretic peptide (ANP) levels in pregnancies subsequently complicated by hypertension

OBJECTIVE

To explore the clinical utility of measuring atrial natriuretic peptide (ANP) in the second and early third trimesters of pregnancy in order to predict pregnancy induced hypertension (PIH).

METHODS AND MATERIALS

The study was done in a University Teaching Hospital. A prospective study of 200 women in their first pregnancy was conducted. ANP was measured at 2 gestational windows, 20-26 weeks and 30-34 weeks. This was correlated with pregnancy outcomes, in particular PIH. Student's t-test was used to compare ANP levels between women who developed PIH and those who did not. The receiver operator curve (ROC) was used to determine its clinical utility.

RESULTS

ANP levels were lower at 20-26 weeks in women who subsequently developed PIH but there was no significant difference at 30-34 weeks between women who had normotensive pregnancies and those who later developed PIH. The character of the ROC would indicate that it is not useful for prediction.

CONCLUSION

ANP levels in the second and early third trimesters has limited clinical utility for the prediction of PIH.

Pro-oxidant effects of cross-linked haemoglobins explored using liposome and cytochrome c oxidase vesicle model membranes

The therapeutic use of cell-free haemoglobin as a blood substitute has been hampered by toxicological effects. A model asolectin (phosphatidylcholine/phosphatidylethanolamine) liposome system was utilized to study the pro-oxidant efficiency of several chemically modified haemoglobins on biological membranes. Lipid peroxidation, resulting from the interactions between haemoglobin and liposomes, was measured by conjugated diene formation and the maximal rates of oxygen uptake. Spectral changes gave insight into the occurrence of the ferryl iron species. The residual reactivity of oxidatively damaged haemoglobins with ligands during incubation with liposomes was assessed from rapid kinetic carbon monoxide-binding experiments. Liposomes in which cytochrome c oxidase was embedded show both haemoglobin and the enzyme to be oxidatively damaged during incubation. The functional state of cytochrome c oxidase was monitored in the presence and absence of a free radical scavenger. Once in contact, both unmodified and modified haemoglobins triggered and maintained severe radical-mediated membrane damage. Differences in the pro-oxidant activities among haemoglobins may be explained by either the differential population of their ferryl intermediates or disparate dimerization and transfer of haem into the membrane with subsequent haem degradation. This study may contribute to a better understanding of the molecular determinants of haemoglobin interactions with a variety of biological membranes.

The cellular isoform of the prion protein, PrPc, is associated with caveolae in mouse neuroblastoma (N2a) cells

A major component of the infectious particle causing spongiform encephalopathies or prion diseases is an aberrant isoform (PrPSc) of a glycosyl-phosphatidylinositol (GPI)-anchored cell surface protein, PrPC. The cellular processes involved in the formation of PrPSc are unclear but involve the internalization of PrPC prior to conversion. Here, we demonstrate that PrPC is associated with caveolin, a structural protein component of caveolae. We show that PrPC and caveolin share similar detergent characteristics and copurify in linear sucrose gradients. PrPC was protected from proteinase K digestion in the caveolin fraction but solubilizing the caveolae prior to proteinase K digestion rendered PrPC susceptible to proteinase K digestion. Our results indicate a physical association between PrPC and caveolin in N2a cells. The implication of these results in relation to prion biogenesis is discussed.

Effects of polymerization on the oxygen carrying and redox properties of diaspirin cross-linked hemoglobin

Human hemoglobin site specifically cross-linked with bis(3,5-dibromosalicyl)fumarate results in a low oxygen affinity hemoglobin-based red cell substitute (alpha-DBBF). Polymerization of alpha-DBBF by bis(maleoylglycylamide) polyethylene glycol (BMAA-PEG) yields poly alpha-DBBF which offers the added benefits of reduced renal clearance and increased retention in the vascular circulation. Oxygen equilibrium curves for poly alpha-DBBF are slightly left-shifted (higher O2 affinity) compared to those of alpha-DBBF; with a diminished cooperativity and a reduced Bohr effect. In rapid mixing experiments (oxygen dissociation and carbon monoxide binding), poly alpha-DBBF exhibits a several fold increase in the overall rate of deoxygenation and carbon monoxide binding kinetics over its cross-linked counterpart. The rate of nitric oxide binding to the oxidized form of poly alpha-DBBF shows little or no change compared to the intramolecularly cross-linked derivative. The reduction of cyanomet poly alpha-DBBF by dithionite is several fold faster than that of HbA0 and alpha-DBBF whereas the slow subsequent cyanide dissociation from the ferrous iron remained unchanged among all proteins. The propensity of poly alpha-DBBF for auto-oxidation is slightly enhanced over alpha-DBBF whereas the extent of oxidative modification by hydrogen peroxide is very similar. Polymerization appears to selectively modify ligand interactions and redox kinetics of the tetrameric cross-linked form which reflects a possibly more open heme pocket. The data suggests that changes in oxygenation properties of hemoglobin brought about by a given modification are not necessarily predictive of other functional changes.

Prenatal gangrene in association with twin-twin transfusion syndrome

Therapeutic amniocentesis is currently used to treat hydramnios secondary to twin-twin transfusion syndrome. We present a case of prenatal gangrene resulting from hyperviscosity in the recipient partner of live-born twins in a pregnancy complicated by acute hydramnios from twin-twin transfusion syndrome and managed with aggressive amniocentesis.

Oestrogen and progesterone receptors in normal human endometrium: comparison of immunocytochemical analysis on frozen and paraffin sections with or without enzymatic pretreatment

Immunocytochemical study in paraffin sections of human endometrium showed that the receptor contents for both oestrogen and progesterone receptors were lower than in the frozen sections although the staining patterns were similar in these two section types. Pretreating the specimens with proteolytic enzymes like trypsin, DNase and pronase improved the oestrogen receptor staining but a better result with progesterone receptor staining was obtained when no enzymatic pretreatment was applied to the sections.

Determinants of birth weight in Vietnamese detainees in Hong Kong

Five hundred and fifty singleton pregnancies amongst Vietnamese Boat People delivering between January and December 1993 were studied post-natally. Multiple regression analysis showed no direct effect of ethnic origin on birth weight. When analyses were repeated on the two main ethnic subgroups we found that, amongst Anamese patients, both gestation at delivery and birth weight independently increased with longer duration of stay in Hong Kong. This relationship was not seen in Vietnamese patients of Chinese ethnic origin. Possible reasons for these different relationships are discussed.

Laparoscopic removal of retained surgical gauze after vaginal hysterectomy

Surgical gauze was retained intraabdominally in a woman who had undergone a vaginal hysterectomy with anterior colporrhaphy. Laparoscopic removal was successfully performed with minimal risk or trauma to the patient. The integrity of the vaginal vault support was maintained and the need for a laparotomy avoided. The use of laparoscopy in vaginal hysterectomy should be considered as this offers the chance to assess the pelvis pre- and post-operatively and to remove the ovaries, where indicated.

Laparoscopic removal of ovarian cysts using a zipper storage bag

Laparoscopic surgery has become increasingly popular in the management of pelvic masses. A major problem during laparoscopic surgery is removal of the specimen. The advantages of the bag retrieval technique using commercially available retrieval bag has been described. However, the size of the bags available is limited and they are relatively expensive. We describe the use of a zipper storage bag for the removal of ovarian cysts in 11 patients undergoing operative laparoscopy without spillage of the cyst contents, the need for abdominal wound extension or to perform a culdotomy. The operating time is reduced, compared to 'purpose designed' bag retrieval systems. This technique is safe, easy to perform and cost-effective.

The influence of obstetric workload on cesarean section rate

The cesarean section rate in a busy obstetric unit was studied in relation to the monthly confinement rate. A total of 30,825 births over a period of 5 years were analyzed. There was a negative correlation between the emergency cesarean section rate and the unit workload (correlation = -.498, 2 tailed p = 0.0001) whilst there was no relationship between workload and the elective cesarean section rate. This suggested that the unit may reach a certain saturation level as far as the emergency cases were concerned during the busy periods. However, there was no evidence that the perinatal outcome was affected by this variation in emergency cesarean section rate.

Childhood injury in Rowan County

Unintentional childhood injury is a public health problem of enormous magnitude. Its relative impact is actually increasing as deaths due to disease continue to decline. Despite this, I am heartened by the fact that this field is receiving more attention, more funding, and is the subject of more research each year. National organizations are providing leadership for state and county health departments which, in turn, provide information and resources at the local level. My studies in Rowan County confirm these effects. Ultimately we want to use the available data to formulate effective interventions that will greatly reduce death and disability. The implementation of such interventions is imperative--the most precious resource of any community is its children.

Acute effects of capsaicin on the postnatal spiral ganglion

Capsaicin exerts both excitatory and desensitizing effects on a subset of sensory neurons during development in the dorsal root ganglion, but it is not known how widespread these effects are in other sensory ganglia especially those not known to have any pain sensitivity. The capsaicin sensitivity of auditory neurons in the spiral ganglion was investigated in acute preparations from three postnatal age groups in the hamster: postnatal days 6-8 (group 1), postnatal days 13-15 (group 2) and postnatal days 20-22 (group 3). Morphologically, capsaicin altered the shape, size, and staining characteristics of spiral ganglion cells (SGCs) across all age groups and this effect was apparently not selective for any identifiable subpopulation. However, SGCs from the youngest age groups were particularly sensitive to capsaicin neurotoxicity. When incubated in media that contained cobalt, capsaicin stimulated cobalt uptake within SGCs. KCl depolarization was able to produce the same level of cobalt uptake as capsaicin treatment. Our data suggest that the extent of capsaicin neurotoxicity in the spiral ganglion is strongly age dependent, involves the entry of calcium ions and is relatively nonspecific.