Interferon treatment of multiple pulmonary malignancies associated with papilloma virus

Over a period of four years, beginning in spring 1988, a previously healthy man developed a primary squamous cell carcinoma of the tonsil, treated with radiotherapy, followed by 10 distinct, primary bronchial squamous cell carcinomas. Four of the cancers were surgically resected, all of which were positive by hybridization for human papilloma virus (type 16). Following the institution of alpha interferon, three smaller lesions disappeared and a larger one shrank in size, facilitating surgical resection. Over the following seven years no new ones have appeared. The finding of papilloma virus in malignancies should prompt consideration of antiviral therapy.

Does Danshen improve disability after acute ischaemic stroke?

OBJECTIVES

Danshen, a Chinese herb, has been used as a standard treatment for acute ischaemic stroke in China. This study assesses the quality of all randomized control trials (RCTs) comparing Danshen of any preparation to without Danshen (placebo or other western or herbal medicines), and to evaluate its effectiveness in improving disability.

MATERIALS AND METHODS

Systematic review through literature search in MEDLINE, Cochrane Library, China Biological Medicine Database and others. The main outcome measure is disability improvement on the Chinese National Disability Scale (CNDS) at 2 weeks after intervention.

RESULTS

Of 33 Danshen control trials for acute ischaemic stroke identified in the literature, none were placebo-controlled. Eleven RCTs comparing Danshen with one of seven Western and two herbal medicines met the inclusion criteria for review, however, these studies were of poor quality. Compared with the nine medicines, the effect of Danshen was inferior in five trials and not significantly different in another six trials. For the two trials comparing Danshen with Buflomedil, the combined odds ratio (OR) was 0.27 (95% CI: 0.12-0.61) favouring Buflomedil, but the test of homogeneity revealed heterogeneity (P = 0.083). For the two trials comparing Danshen with Naloxone, the combined OR was 0.16 (95% CI: 0.07-0.40) favouring Naloxone. However, none of the nine medicines per se has been proven effective in post-stroke disability improvement.

CONCLUSIONS

The existing Danshen RCTs are not placebo-controlled and are of poor quality, therefore, there is no substantial evidence that Danshen is effective. Systematic review on RCTs comparing Danshen with other medicines does not support the notion that Danshen may be beneficial to disability improvement after acute ischaemic stroke.

Plasma ghrelin and resistin concentrations are suppressed in infants of insulin-dependent diabetic mothers

This study aimed to investigate 1) the effect of maternal diabetes mellitus on ghrelin, resistin, leptin, and insulin in term newborns; 2) the interrelationship of these metabolic hormones in the early postnatal period; and 3) the association of the hormones with anthropometric parameters at birth. A total of 120 term newborns were prospectively enrolled and categorized into three groups: 40 were infants of nondiabetic mothers (group N), 42 were infants born to mothers with gestational diabetes on low energy dietary treatment (group D), and 38 were infants born to mothers with preexisting or severe gestational diabetes who required exogenous insulin for stabilization of blood sugar during pregnancy (group I). Plasma ghrelin and resistin were significantly lower in group I than in either group N or group D infants (P < 0.048). Plasma ghrelin and subscapular skinfold thickness were significantly higher in female than in male infants [plasma ghrelin: median (interquartile range), 3.8 (3.0-4.8) vs. 3.0 (2.4-4.0) ng/ml in females and males, respectively; P = 0.003; subscapular skinfold thickness: 4.9 (4.2-5.6) vs. 4.6 (3.9-5.2) mm; P = 0.03]. In group N, plasma ghrelin was significantly, but negatively, associated with birth weight (r = -0.31; P = 0.05) and body length (r = -0.33; P = 0.04), whereas in group I, plasma ghrelin was negatively correlated with plasma resistin (r = -0.37; P = 0.02). Plasma ghrelin and resistin are suppressed in infants of insulin-dependent diabetic mothers, suggesting that the metabolic hormonal system is probably operational in fetal and early postnatal life. A low circulating ghrelin concentration may be advantageous to these infants, because a reduction in appetite may prevent excessive weight gain postnatally and counterbalances the in utero anabolic effect of hyperinsulinism in poorly controlled diabetic mothers. The suppressive effect of insulin on resistin may partially explain the excess accumulation of adipose tissue in infants of diabetic mothers by reducing the inhibitory effect of resistin on adipogenesis. Female infants have significantly higher plasma ghrelin levels than male infants, suggesting that sexual dimorphism exists in utero. This study has also shown an association between some of the metabolic hormones in specific groups of infants and thus suggests that these hormones could have interacted in utero to regulate growth and fat storage during this critical period.

The effect of severe acute respiratory syndrome on emergency airway management

Study objectives: From early March 2003 to late May 2003, severe acute respiratory syndrome (SARS) was detected in Singapore. Two hundred thirty-eight patients were infected; 33 died. Forty-two percent were health care workers. The whole medical system in the country was put under stress. One major public hospital became the designated SARS hospital. Emergency cases were diverted to the remaining public hospitals, of which Singapore General Hospital was the main recipient. The increase in workload, new infection control procedures including mandatory wearing of the positive airway pressure respirator and personal protective equipment (PPE), and limiting the number of person-contacts with each patient were thought to affect resuscitation and airway management. Our aim is to study the effects of wearing of PPE and the restriction in number of resuscitation personnel on airway management during the SARS crisis.

Methods: The emergency department has an ongoing airway registry that prospectively captures patient demographics, diagnosis, indications for intubation, persons and discipline of intubating physician, number of attempts, method of intubation, success rates, and complications. The data were divided into 3 periods: (1) before PPE was instituted from November 1, 2002, to March 31, 2003; (2) during SARS (when PPE use was mandatory) from April 1 to July 31, 2003; and (3) after SARs (when PPE use was nonmandatory but encouraged) from August 1 to December 31, 2003.

Results: There was no change in patient demographics during the 3 periods, but there was a change in the patient diagnoses in period 2, with decreases in the proportion of respiratory and cardiac cases and increases in neurology and trauma cases. These changes reverted to the previous distribution in period 3. The alarming discovery was that whereas in period 1 (pre-SARS), resident medical officers attempted intubations 45% of the time, this figure went down to 35% in period 2 (SARS) and 23% in period 3 (post-SARS). Anesthetists performed 1.2%, 8%, and 0% of emergency intubations in periods 1, 2, and 3, respectively. Attending emergency physicians performed 54%, 56%, and 77% of intubations in periods 1, 2, and 3, respectively. The complication/peri-intubation event rates were 10.5%, 9.9%, and 9.4% in periods 1, 2, and 3, respectively. The success rate for residents was 80.8%, 89%, and 86.2% in periods 1, 2, and 3, respectively.

Conclusion: The wearing of PPE and positive airway pressure respirator is thought to make intubation more difficult, as seen by the increase in proportion of intubations performed by anesthetists in period 2 and by attending emergency physicians in periods 2 and 3. The infection control policy that restricts the number of health care staff attending to each patient may have influenced the department's decision to allow only the most confident or experienced personnel to manage the airway. The exposure of junior residents in emergency airway management during SARS and the immediate post-SARS period was decreased. This trend should be further monitored, and intervention may be necessary should it continue to decline.

Effects of inhaled corticosteroids on systemic blood pressure in preterm infants

OBJECTIVE

To assess the effect of inhaled fluticasone propionate on (i) systemic blood pressure, and (ii) the need for volume expanders (crystalloids and colloids) and inotropes for blood pressure support in preterm, very low birth weight (VLBW) infants.

METHODS

Ventilated VLBW infants, less than 32 weeks of gestation, with respiratory distress syndrome were randomised to receive a 14-day course of either fluticasone propionate (500 microg/puff, 2 puffs every 12 h; n=27) or placebo (n=26) with a metered dose inhaler-spacer device. The response of treatment was assessed by comparing the use of volume expanders, inotropes, and the average and the lowest systolic, mean and diastolic blood pressures in 6 hourly epochs between the 2 groups.

RESULTS

There were no significant differences in the average or the lowest systolic, mean and diastolic blood pressures in 6 hourly epochs between the 2 groups. However, the total volume of crystalloids and colloids requirement was significantly greater in control than in treated infants (p=0.03). There was also a trend towards greater consumption of the total cumulative dose of dopamine in the control infants (p=0.10).

CONCLUSIONS

Fluticasone-treated infants required significantly less volume of crystalloids and colloids for blood pressure support compared with control infants. Further larger scale studies are required to determine whether inhaled corticosteroids could minimise the use of volume replacement therapy and inotropes in the treatment of hypotension in preterm infants in the early postnatal period.

Combined use of alcohol hand rub and gloves reduces the incidence of late onset infection in very low birthweight infants

OBJECTIVE

To assess the incidence of late onset (> 72 hours) infection and necrotising enterocolitis (NEC) in very low birthweight (VLBW) infants in two 36 month periods using two hand hygiene protocols: conventional handwashing (HW; first 36 month period); an alcohol hand rub and gloves technique (HR; second 36 month period).

METHOD

VLBW infants admitted to the neonatal intensive care unit during the period December 1993-November 1999 were eligible. A new hand hygiene protocol using alcohol handrub and gloves was introduced in December 1996. Each patient's case record was reviewed retrospectively by two independent investigators using a standard data collection form. The incidence of NEC and systemic infections, including bacterial or fungal septicaemia, meningitis, and peritonitis, in the two periods were compared.

RESULTS

The HW and HR groups contained 161 and 176 VLBW infants respectively. The incidence of late onset systemic infection decreased from 13.5 to 4.8 episodes (including NEC)/1000 patient days after introduction of the HR regimen, representing a 2.8-fold reduction. Similarly, the incidence of Gram positive, Gram negative, and fungal infections decreased 2.5-fold, 2.6-fold, and 7-fold respectively. There was also a significant reduction in the incidence of NEC in the HR group (p < 0.0001). Subgroup analysis revealed that the incidence of methicillin resistant Staphylococcus aureus (MRSA) septicaemia was significantly decreased in the second 36 month period (p = 0.048). The clinical data suggest that infants in the HW group had significantly earlier onset of sepsis (p < 0.05) and required oxygen supplementation for longer (p < 0.05) than those in the HR group. Significantly more VLBW infants were discharged from the neonatal intensive care unit without ever being infected (p < 0.0001), and also significantly fewer infants had more than one episode of infection in the HR group (p < 0.0001).

CONCLUSION

The introduction of the HR protocol was associated with a 2.8-fold reduction in the incidence of late onset systemic infection, and also a significant decrease in the incidence of MRSA septicaemia and NEC in VLBW infants. This decrease in infection rate was maintained throughout the second 36 month period.

Transient adrenocortical insufficiency of prematurity and systemic hypotension in very low birthweight infants

OBJECTIVES

A proportion of preterm, very low birthweight (VLBW, < 1500 g) infants may show inadequate adrenal response to stress in the immediate postnatal period. The human corticotrophin releasing hormone (hCRH) stimulation test was used to: (a) determine the relation between pituitary-adrenal response and systemic blood pressure in these infants; (b) characterise the endocrinological features of transient adrenocortical insufficiency of prematurity (TAP).

STUDY DESIGN

A total of 226 hCRH tests were performed on 137 VLBW infants on day 7 and 14 of life in a tertiary neonatal centre.

RESULTS

Basal, peak, and incremental rise in serum cortisol (Delta Cort(0-30)) on day 7 were associated significantly with the lowest systolic, mean, and diastolic blood pressures recorded during the first two weeks of life (r > 0.25, p < 0.005). These cortisol concentrations also correlated significantly but negatively with the maximum and total cumulative dose of dopamine (r > -0.22, p < 0.02), dobutamine (r > -0.18, p < 0.04), and adrenaline (r > -0.26, p < 0.004), total volume of crystalloid (r > -0.22, p < 0.02), and duration of inotrope treatment (r > -0.25, p < 0.006). Multivariate regression analysis of significant factors showed that the lowest systolic, mean, and diastolic blood pressures remained independently associated with serum cortisol (basal, peak, and Delta Cort(0-30)) on day 7. Hypotensive infants requiring inotropes (group 2) were significantly less mature and more sick than infants with normal blood pressure (group 1). The areas under the ACTH response curves were significantly greater in group 2 than in group 1, on both day 7 (p = 0.004) and day 14 (p = 0.004). In contrast, the area under the cortisol response curve was significantly greater in group 1 than in group 2 on day 7 (p = 0.001), but there was no significant difference between the two groups on day 14. In addition, serum cortisol at the 50th centile in hypotensive infants had high specificity and positive predictive value (0.80-0.93 and 0.81-0.89 respectively) for predicting early neonatal hypotension.

CONCLUSIONS

This study characterises the fundamental endocrinological features of TAP: normal or exaggerated pituitary response; adrenocortical insufficiency; good recovery of adrenal function by day 14 of postnatal life. The results also provide the centiles of serum cortisol for hypotensive patients and infants with normal blood pressure, and show a significant relation between serum cortisol and blood pressure in VLBW infants.

Early pituitary-adrenal response and respiratory outcomes in preterm infants

OBJECTIVE

To assess the influence of circulating (basal) and stimulated plasma adrenocorticotrophin (ACTH) and serum cortisol on the duration of oxygen supplementation and development of chronic lung disease (CLD) in preterm, very low birthweight infants.

METHODS

A total of 226 human corticotrophin releasing hormone stimulation tests were performed on 137 very low birthweight infants on days 7 and 14 in a tertiary neonatal centre.

RESULTS

Multivariate regression analysis showed that the duration of oxygen supplementation was negatively associated with birth weight, but positively associated with alveolar-arterial oxygen gradient (A-aDO(2)) on the first day and with basal serum cortisol on day 14. In addition, the multivariate classification and regression trees model indicated that the two most useful indices for predicting CLD were clinical risk index for babies (CRIB) score (> 9) and peak serum cortisol (> 740 nmol/l) on day 14. The sensitivity, specificity, positive and negative predictive values of these factors for predicting CLD were 53%, 80%, 81%, and 70% respectively.

CONCLUSIONS

The findings suggest that birth weight, severity of initial respiratory failure as reflected by the A-aDO(2) gradient, and continuing "stress" with persistent increase in serum cortisol on day 14 are significant risk factors associated with the duration of oxygen supplementation, whereas early pituitary-adrenal response (basal and peak plasma ACTH and serum cortisol on day 7) is not an independent risk factor. Although CRIB score in combination with peak serum cortisol on day 14 are useful predictors of CLD, the need to use a stimulation test and the relatively late timing of the forecast render these indices unattractive for routine clinical use.

Simplified intensity-modulated arc therapy for dose escalated prostate cancer radiotherapy

Simplified intensity-modulated arc therapy (SIMAT) employs forward planned, conformal, and avoidance arc combinations with dynamic multileaf collimation (MLC) as a simpler alternative to other forms of intensity-modulated radiotherapy (IMRT). In this work, we compare SIMAT with 4-field (4F) and 6-field (6F) 3D conformal radiation therapy (CRT) for prostate cancer treatment. Prostate, seminal vesicle, bladder, and rectum were contoured on the CT images of 10 patients being planned for radiotherapy. Two planning target volumes (PTV) were defined: PTV1 (prostate + seminal vesicles + 1.0-cm margin) and PTV2 (prostate + 1.0-cm margin). SIMAT, 4F, and 6F plans were generated with a prescription dose of 78 Gy to prostate and 54 Gy to the seminal vesicles. Differences in the 3 techniques in terms of target and rectal coverage were compared. In addition, dose distributions of the SIMAT plans were verified with measurements in a phantom. Mean dose to PTV2 (4F, 76 Gy; 6F, 78 Gy; SIMAT, 76 Gy) and the dose delivered to 95% of the target volume (D(95)) were similar between the 3-techniques. Target conformity was better with SIMAT. Mean dose and calculated NTCP for the rectum were lower for SIMAT than those for 4F and 6F plans (4F 55.6 Gy vs. 6F 49.0 Gy vs. SIMAT 42.7 Gy). Mean dose to femoral heads was lower for the 4F technique vs. 6F and SIMAT techniques (4F 44.5 Gy vs. 6F 48.9 Gy vs. SIMAT 49.5 Gy). In-phantom measurement demonstrated good agreement between the plans and SIMAT treatments delivered in phantom. We concluded that SIMAT demonstrates advantages over 4F and 6F in terms of target conformity mean rectal dose and NTCP with good reproducibility in phantom. On the basis of this analysis, we have commenced a clinical pilot study of SIMAT for prostate cancer radiotherapy.

Psychosocial impact of breast cancer surgeries in chinese patients and their spouses

BACKGROUND AND PURPOSE

This pilot study assesses the psychosocial impact of different modalities of breast cancer surgery in Chinese patients and their husbands.

METHODS

Thirty-six patients who underwent conservative breast therapy (BCT) for breast cancer were compared with 36 women who underwent total mastectomy (TM) on four aspects of psychosocial adjustment. They were matched in pairs in terms of stage of disease, age and time since surgery. Where available, their husbands were also consented for similar assessment.

RESULTS

Women who underwent BCT showed a significantly better response to their body and sexual image than those who underwent TM. This difference did not translate into any significant difference in terms of emotional and symptomatic aspects, daily activities, or fear of recurrences. The husbands of patients in the TM group showed significantly more emotional and symptomatic distress and greater change in the perception of their wives' body and sexual images.

CONCLUSION

This is the first of such study conducted in a Chinese population. The lack of differences in certain psychosocial aspects may indicate a generally good adjustment in the TM patients after their surgery. It may also relate to the fact that volunteers for the study were themselves representative only of the patient population who adapted well to the surgery, and those patients who were emotionally distressed tended to decline to participate. Psychosocial disruption in the patients' families is reflected in our study where patients' husbands in the TM group were significantly more disturbed. However, due to the limited number of patients studied, the findings are not yet conclusive and require further studies for confirmation.

Auricular anthropometry of Hong Kong Chinese babies

OBJECTIVES

To provide a database of the auricular measurements of Chinese infants born in Hong Kong.

DESIGN

Prospective cross-sectional study.

SETTING AND SAMPLE POPULATION

A total of 2384 healthy singleton, born consecutively at the Prince of Wales Hospital and the Union Hospital from October 1998 to September 2000, were included in the study. The range of gestation was 33-42 weeks.

MEASUREMENTS AND RESULTS

Measurements included ear width (EW), ear length (EL) and ear position (EP). The data show generally higher values for males in the parameters measured. When compared with previously published data for Caucasian and Jordanian term babies, Chinese babies have shorter EL. The ears were within normal position in nearly all our infants.

CONCLUSION

The human ear appears to grow in a remarkably constant fashion. This study establishes the first set of gestational age-specific standard of the ear parameters for Chinese new-borns, potentially enabling early syndromal diagnosis. There are significant inter-racial differences in these ear parameters.

An algorithm for systematic selection of beam directions for IMRT

Selection of the number of beams and their directions can be an important problem in radiation therapy, especially when a tumor surrounds a critical organ or is surrounded by multiple critical organs. Beam directions, in this sense, are chosen to not only avoid critical organs, but also to achieve better target dose uniformity. In intensity-modulated radiation therapy (IMRT), optimization of beam directions is further complicated due to the dependence of one beam direction on its corresponding beamlet intensities and the beamlet intensities of all other beam directions. The result is an excessively enlarged search space, even when the number of beams is small (two to three). Until now, only a handful of publications exist regarding beam direction optimization in IMRT. Here, we report a new systematic approach that determines a suitable number of "more optimal" beam directions without optimizing a complicated objective function or resorting to brute force. We start by assuming that beam directions chosen for an N-beam plan are candidates for beam directions in the search for an (N + 1)-beam plan. Knowing that beam directions in an N-beam plan are not always the best choices for the (N + 1)-beam plan, we introduce into the beam direction selection process an analysis of the beamlet weights of every beam direction set sampled. If the relative weights of any particular beam compared to other beams are insignificant and hence have no significant effect on the quality of the treatment plan, then we eliminate this beam from the plan. The algorithm terminates basically when the relative weights of the last beam compared to other beams are insignificant or the replacement of an eliminated beam does not improve the plan. This concept was applied to three two-dimensional phantoms and each plan was compared to a standard equally spaced IMRT plan in terms of dose distributions, dose-volume histograms, and objective function values. The results show improvements in both target dose uniformity and critical organ sparing often with a fewer number of beams than standard equally spaced beam plans.

Cough frequency in children with stable asthma: correlation with lung function, exhaled nitric oxide, and sputum eosinophil count

BACKGROUND

A study was undertaken to assess the correlation between cough frequency in asthmatic children with lung function and two non-invasive markers of airway inflammation.

METHODS

Thirty two children of median age 12.0 years (interquartile range (IQR) 9.5-13.4) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring over 17 hours and 40 minutes. Coughing episodes were counted both as individual spikes and as clusters.

RESULTS

Complete cough frequency data were available in 29 children (90%) and their median forced expiratory volume in 1 second (FEV1) and eNO were 88.5% (IQR 79.5-98) and 23.9 ppb (IQR 11.4-41.5), respectively. The median number of cough episodes was 14 (IQR 7.0-24.0) which was significantly higher than that of normal children (6.7 (IQR 4.1-10.5), p<0.001). Sputum induction was successful in 61% of the subjects; the median induced sputum eosinophil count was 0.05% (IQR 0-9.0). Cough frequency was found to have a significant positive correlation with eNO (Spearman's r =0.781, p<0.001) but not with FEV1 or sputum eosinophil count (r =-0.270, p=0.157; r =0.173, p=0.508, respectively).

CONCLUSIONS

Children with stable asthma have increased cough frequency compared with normal controls and cough frequency was greater during the day than at night. Cough may be a more sensitive marker of airway inflammation than simple spirometry.

Evaluation of an education program for elementary school children with asthma

To evaluate the effectiveness of a comprehensive asthma management education program for 7- to 12-year-old children with asthma, entitled Roaring Adventures of Puff (RAP), 18 elementary schools in Edmonton were randomized to intervention and control groups. Participating in the program were 76 students with asthma in the intervention schools and 86 in the control schools. Children in the intervention schools had statistically significant improvements in unscheduled doctor visits, missed school days, moderate-to-severe parent rating of severity, severity of shortness of breath, limitations in the kind of play, and correct use of medications. Unscheduled doctor visits and missed school days were the only significant improvements in the control group; however, improvements were about half that of the intervention group. The results showed that a comprehensive, school-based asthma education program is feasible and improves outcomes.

Facial anthropometry of Hong Kong Chinese babies

OBJECTIVES

To provide a database of the craniofacial measurements of Chinese infants born in Hong Kong.

DESIGN

Prospective cross-sectional study.

SETTING AND SAMPLE POPULATION

A total of 2371 healthy singleton, born consecutively at the Prince of Wales Hospital and the Union Hospital from June 1998 to June 2000, were included in the study. The range of gestation was 33-42 weeks.

MEASUREMENTS AND RESULTS

Measurements included facial width (FW), facial height (FH), nasal length (NL), nasal width (NW), and length of the philtrum (PhilL). The facial, nasal, nasofacial and nasozygomatic indices were derived. The data show generally higher values for males in the parameters measured. The various indices remained remarkably constant and did not vary significantly between the two genders or with gestation. When compared with previously published data for white people term babies, Chinese babies have similar NW but shorter philtrum length.

CONCLUSION

The human face appears to grow in a remarkably constant fashion as defined by the various indices of facial proportions. This study establishes the first set of gestational age-specific standard of such craniofacial parameters for Chinese new-borns, potentially enabling early syndromal diagnosis. There are significant inter-racial differences in these craniofacial parameters.

Optimization of helical tomotherapy treatment plans for prostate cancer

Helical tomotherapy (HT) is a novel treatment approach where the ring gantry irradiation geometry of a helical CT scanner is combined with an intensity-modulated megavoltage x-ray fan beam. An inverse treatment planning system (TomoTherapy Inc., Madison) was used to optimize the treatment plans for ten randomly selected prostate patients. Five different sets of margins (2, 5, 7.5 and 10 mm uniform 3D margins and a non-uniform margin of 5 to 10 mm) were employed for the prostate (GTV2) and seminal vesicles (GTV1). The dose distribution was evaluated in targets, rectum, bladder and femoral heads. HT plans are characterized by a rapid dose fall off around the target in all directions resulting in low doses (less than 30% of the dose at ICRU reference point) to the femurs in all cases. Up to a margin of 5 mm for target structures, it was always possible to satisfy the requirements for dose delivery set by RTOG protocol P-0126. Using a 'class solution', HT plans require minimal operator interaction and result in excellent sparing of normal structures in prostate radiotherapy.

Functional analysis of the structural basis of homophilic cadherin adhesion

The structures of many cell surface adhesion proteins comprise multiple tandem repeats of structurally similar domains. In many cases, the functional significance of this architecture is unknown, and there are several cases in which evidence for individual domain involvement in adhesion has been contradictory. In particular, the extracellular region of the adhesion glycoprotein cadherin consists of five tandemly arranged domains. One proposed mechanism postulated that adhesion involves only trans interactions between the outermost domains. However, subsequent investigations have generated several competing models. Here we describe direct measurements of the distance-dependent interaction potentials between cadherin mutants lacking different domains. By quantifying both the absolute distances at which opposed cadherin fragments bind and the quantized changes in the interaction potentials that result from deletions of individual domains, we demonstrate that two domains participate in homophilic cadherin binding. This finding contrasts with the current view that cadherins bind via a single, unique site on the protein surface. The potentials that result from interactions involving multiple domains generate a novel, modular binding mechanism in which opposed cadherin ectodomains can adhere in any of three antiparallel alignments.

Updated gestational age specific birth weight, crown-heel length, and head circumference of Chinese newborns

OBJECTIVE

To construct gestation specific standards of birth weight, crown-heel length, and head circumference of Chinese infants.

DESIGN

A prospective cross sectional population study.

METHODS

The birth weight, crown-heel length, and head circumference were prospectively measured using standard equipment in newborns delivered at 24-42 weeks gestation in the maternity units of 10 public hospitals and two private hospitals in Hong Kong. The findings were used to construct gestation specific standards of these variables. The LMS method using maximum penalised likelihood was used to perform model fitting. The results were compared with those obtained from a cohort of infants born in the same locality between 1982 and 1986.

RESULTS

From October 1998 to September 2000, a total of 10 032 infants were measured, representing 9.6% of the total deliveries in Hong Kong during that period. An extra 307 infants with gestation < or = 35 weeks were recruited from October 2000 to June 2001. Each of the three variables showed a normal distribution at each gestational week. Gestation specific reference standards for each variable were constructed for male and female infants separately. Comparison with the 1982-1986 cohort showed a significant secular trend to increased birth weight. The trend was small, but significant, for crown-heel length and head circumference.

CONCLUSION

These growth standards will provide useful references for the care of newborns of ethnic Chinese origin. These standards, especially that for birth weight, should be updated regularly.