Natural history of epilepsy in argininosuccinic aciduria provides new insights into pathophysiology: A retrospective international study

OBJECTIVE

Argininosuccinate lyase (ASL) is integral to the urea cycle, which enables nitrogen wasting and biosynthesis of arginine, a precursor of nitric oxide. Inherited ASL deficiency causes argininosuccinic aciduria, the second most common urea cycle defect and an inherited model of systemic nitric oxide deficiency. Patients present with developmental delay, epilepsy, and movement disorder. Here we aim to characterize epilepsy, a common and neurodebilitating comorbidity in argininosuccinic aciduria.

METHODS

We conducted a retrospective study in seven tertiary metabolic centers in the UK, Italy, and Canada from 2020 to 2022, to assess the phenotype of epilepsy in argininosuccinic aciduria and correlate it with clinical, biochemical, radiological, and electroencephalographic data.

RESULTS

Thirty-seven patients, 1-31 years of age, were included. Twenty-two patients (60%) presented with epilepsy. The median age at epilepsy onset was 24 months. Generalized tonic-clonic and focal seizures were most common in early-onset patients, whereas atypical absences were predominant in late-onset patients. Seventeen patients (77%) required antiseizure medications and six (27%) had pharmacoresistant epilepsy. Patients with epilepsy presented with a severe neurodebilitating disease with higher rates of speech delay (p = .04) and autism spectrum disorders (p = .01) and more frequent arginine supplementation (p = .01) compared to patients without epilepsy. Neonatal seizures were not associated with a higher risk of developing epilepsy. Biomarkers of ureagenesis did not differ between epileptic and non-epileptic patients. Epilepsy onset in early infancy (p = .05) and electroencephalographic background asymmetry (p = .0007) were significant predictors of partially controlled or refractory epilepsy.

SIGNIFICANCE

Epilepsy in argininosuccinic aciduria is frequent, polymorphic, and associated with more frequent neurodevelopmental comorbidities. We identified prognostic factors for pharmacoresistance in epilepsy. This study does not support defective ureagenesis as prominent in the pathophysiology of epilepsy but suggests a role of central dopamine deficiency. A role of arginine in epileptogenesis was not supported and warrants further studies to assess the potential arginine neurotoxicity in argininosuccinic aciduria.

A new respiratory scoring system for evaluation of respiratory outcomes in children with spinal muscular atrophy type1 (SMA1) on SMN enhancing drugs

Nusinersen (NUS), the first treatment approved for Spinal Muscular Atrophy type 1 (SMA1), was made available in the UK for SMA1 through the Expanded Access Program (EAP) in 2017. The Great Ormond Street Respiratory (GSR) score was developed as an objective respiratory assessment for children with SMA1 during their treatment. Aims: Track respiratory status of SMA1 children over the course of Nusinersen treatment and compare GSR scores amongst SMA1 sub-types. Single centre study on SMA1 patients using the GSR score at set time points: prior to first NUS dose; 2 weeks post end of loading doses; 2 weeks post-subsequent doses. GSR score ranges 1-28, being 1-9 = Stable minimal support, thorough to 23-28 = Poor reserve with maximum support. 20 SMA1 children underwent NUS treatment between January 2017 - November 2018. Median age of diagnosis was 5.0 months. NUS started at median of 9.57 months. From 5th dose onwards, GSR scores were significantly lower for Type 1C patients compared to Type 1B By month 18, irrespective of subtypes, the whole cohort appears to stabilise GSR Scores. As treatment duration increases, an overall stabilisation of respiratory status across the cohort was observed. Further longitudinal studies are needed to validate the GSR.

Respiratory and upper limb function as outcome measures in ambulant and non-ambulant subjects with Duchenne muscular dystrophy: A prospective multicentre study

The field of translational research in Duchenne muscular dystrophy (DMD) has been transformed in the last decade by a number of therapeutic targets, mostly studied in ambulant patients. A paucity of studies focus on measures that capture the non-ambulant stage of the disease, and the transition between the ambulant and non-ambulant phase. In this prospective natural history study, we report the results of a comprehensive assessment of respiratory, upper limb function and upper limb muscle strength in a group of 89 DMD boys followed in 3 European countries, 81 receiving corticosteroids, spanning a wide age range (5-18 years) and functional abilities, from ambulant (n = 60) to non-ambulant (n = 29). Respiratory decline could be detected in the early ambulatory phase using Peak Expiratory Flow percentage predicted (PEF%), despite glucocorticoid use (mean annual decline: 4.08, 95% CI [-7.44,-0.72], p = 0.02 in ambulant; 4.81, 95% CI [-6.79,-2.82], p < 0.001 in non-ambulant). FVC% captured disease progression in non-ambulant DMD subjects, with an annual loss of 5.47% (95% CI [-6.48,-4.45], p < 0.001). Upper limb function measured with the Performance of Upper Limb (PUL 1.2) showed an annual loss of 4.13 points (95% CI [-4.79,3.47], p < 0.001) in the non-ambulant cohort. Measures of upper limb strength (MyoGrip and MyoPinch) showed a continuous decline independent of the ambulatory status, when reported as percentage predicted (grip force -5.51%, 95% CI [-6.54,-4.48], p < 0.001 in ambulant and a slower decline -2.86%; 95% CI -3.29,-2.43, p < 0.001, in non-ambulant; pinch force: -2.66%, 95% CI [-3.82,-1.51], p < 0.001 in ambulant and -2.23%, 95% CI [-2.92,-1.53], p < 0.001 in non-ambulant). Furthermore, we also explored the novel concept of a composite endpoint by combining respiratory, upper limb function and force domains: we were able to identify clear clinical progression in patients in whom an isolated measurement of only one of these domains failed to appreciate the yearly change. Our study contributes to the field of natural history of DMD, linking the ambulant and non-ambulant phases of the disease, and suggests that composite scores should be explored further.

Maternal alcohol consumption

Background Despite decades of research, the aetiology of attention deficit disorder with hyperactivity (ADHD) remains largely unknown. Next to a strong genetic component, increasing evidence suggests additional adverse impact of environmental factors, two of which have, although controversially, withstood meta-analysis: gestational exposure to smoking (OR 2.39) and low birth weight (OR 2.64). Several studies have investigated a possible association between prenatal exposure to alcohol and ADHD, although the matter is complicated due to foetal alcohol syndrome disorders (FASD) with ADHD-like symptoms. Questions Can an estimate of the effect of gestational exposure to alcohol for ADHD be determined? What is the relevance of primary care services in screening and intervention in mild to moderate drinking in pregnant women? Method MEDLINE, Cinahl, PsychInfo, EMBASE (1995-2008) were searched for articles in English, supplemented by a manual search. Out of 23 reviewed studies, three were included in the metaanalysis; one further study was added to undertake a sub-analysis comparing severe versus mild alcohol consumption. Summary odds ratios (OR) were extracted and fixed/random-effects meta-analysis were used for combining the OR's. Heterogeneity across the studies was formally assessed using Cochran's Q. Results An OR of 2.33 (95% CI, 1.18-4.61), (z = 2.43, p = 0.02) suggests that exposed children are 2.33 times more likely to have ADHD than non exposed children. Discussion Our meta-analysis suggests that children exposed to alcohol during pregnancy are at risk for ADHD. However, evidence is sparse and it remains uncertain whether a causal association exists. Further research is needed into dose-response relationship, timing of exposure, influence of genetic factors involved in maternal alcohol abuse and the role of FASD in ADHD-like symptoms. If a detrimental effect of mild to moderate drinking on the offspring is supported by stronger evidence, primary care services could have a major role in prevention and early intervention. This would be in addition to their already established role in helping heavy drinking mothers.

Neonatal extracorporeal membrane oxygenation: practice patterns and predictors of outcome in the UK

OBJECTIVE

To review the UK neonatal extracorporeal membrane oxygenation (ECMO) service and identify predictors of outcome.

DESIGN

Retrospective review of the national cohort.

PATIENTS AND INTERVENTIONS

718 neonates received ECMO for respiratory failure between 1993 and 2005.

MEASUREMENTS AND RESULTS

Diagnoses were: 48.0% meconium aspiration syndrome (97.1% survivors), 15.9% congenital diaphragmatic hernia (CDH; 57.9% survivors), 15.9% sepsis (62.3% survivors), 9.5% persistent pulmonary hypertension (79.4% survivors), 5.6% respiratory distress syndrome (92.5% survivors) and 5.1% congenital lung abnormalities (24.3% survivors). The overall survival rate of 79.7% compared favourably with the worldwide Extracorporeal Life Support Organization (ELSO) Registry. Over the period of review, pre-ECMO use of advanced respiratory therapies increased (p<0.001), but ECMO initiation was not delayed (p = 0.61). The use of veno-venous (VV) ECMO increased (p<0.001) and average run time fell (p = 0.004). Patients treated with VV ECMO had a survival rate of 87.7% compared with 73.4% in the veno-arterial (VA) ECMO group; only 42.4% of those needing conversion from VV to VA ECMO survived. In non-CDH neonates, lower birth weight, lower gestational age, older age at ECMO and higher oxygenation index (OI) were associated with increased risk of death. In CDH neonates, lower birth weight and younger age at ECMO were identified as risk factors for death.

CONCLUSION

The UK neonatal ECMO service achieves good outcomes and with overall survival rate reaching 80% compares favourably with international results. Advanced respiratory therapies are used widely in UK ECMO patients. Identification of higher OI and older age at ECMO as risk factors in non-CDH neonates reinforces the importance of timely referral for ECMO.

The presence of vesicoureteric reflux does not identify a population at risk for renal scarring following a first urinary tract infection

BACKGROUND

Childhood urinary tract infection (UTI) with or without vesicoureteric reflux (VUR) may predispose to renal scarring. There is no clear consensus in the literature regarding imaging following UTI in infancy.

AIMS

To define the role of cystography following a first UTI in children aged under 1 year, when urinary tract ultrasonography (US) is normal.

METHODS

Retrospective data collection of 108 children (216 renal units) aged under 1 year at the time of a bacteriologically proven UTI. All had a normal US and underwent both catheter cystogram and DMSA test. Sensitivity, specificity, likelihood ratios positive and negative, and diagnostic odds ratio were calculated for VUR on cystography versus scarring on DMSA.

RESULTS

VUR was shown in 25 (11.6%) renal units. Scarring on DMSA was seen in 8 (3.7 %) kidneys. Only 16% of kidneys with VUR had associated scarring; 50% of scarred kidneys were not associated with VUR. The likelihood ratio positive was 4.95 (95% CI 2.22 to 11.05) and the likelihood ratio negative was 0.56 (95% CI 0.28 to 1.11). The diagnostic odds ratio was 8.9, suggesting that cystography provided little additional information.

CONCLUSION

Since only 16% of children with VUR had an abnormal kidney, the presence of VUR does not identify a susceptible population with an abnormal kidney on DMSA. In the context of a normal ultrasound examination, cystography contributes little to the management of children under the age of 1 year with a UTI. In this context, a normal DMSA study reinforces the redundancy of cystography.

Maternal phenylketonuria: report from the United Kingdom Registry 1978-97

BACKGROUND

The effects of maternal phenylalanine on the fetus include facial dysmorphism, microcephaly, intrauterine growth retardation, developmental delay, and congenital heart disease.

AIMS

To evaluate the impact of phenylalanine restricted diet in pregnant women with phenylketonuria (PKU) on their offspring.

METHODS

Data on virtually all pregnancies of women with PKU in the United Kingdom between 1978 and 1997 were reported to the United Kingdom PKU Registry. The effect of the use and timing in relation to pregnancy of a phenylalanine restricted diet on birth weight, birth head circumference, the presence or absence of congenital heart disease (CHD), 4 year developmental quotient, and 8 year intelligence quotient were examined.

RESULTS

A total of 228 pregnancies resulted in live births (seven twin pregnancies were excluded). In 110 (50%), diet started before conception. For this group mean (SD) birth weight was 3160 (612) g, birth head circumference 33.6 (1.9) cm, 4 year DQ 108.9 (13.2), 8 year IQ 103.4 (15.6), and incidence of CHD was 2.4%. In comparison, for those born where treatment was started during pregnancy (n = 91), birth weight was 2818 (711) g, birth head circumference 32.7 (2.0) cm, 4 year DQ 96.8 (15.0), 8 year IQ 86.5 (13.0), and incidence of CHD was 17%. Month-by-month regression analyses suggested that metabolic control by 12-16 weeks gestation had most influence on outcome.

CONCLUSIONS

Many features of the maternal PKU syndrome are preventable by starting a phenylalanine restricted diet. Women with PKU and their carers must be aware of the risks and should start the diet before conception, or as soon after as possible.

The GP perspective: problems experienced in providing diabetes care in UK general practice

AIMS

To describe the problems and barriers perceived by general practitioners (GPs) whilst providing diabetes care in primary care in England and Wales and to identify those health authorities (HAs) in which primary care reported the most and least difficulty.

DESIGN

Descriptive postal survey using a self-administered questionnaire.

SUBJECTS

One thousand eight hundred and seventy-three randomly sampled GP practices (one in five practices).

RESULTS

One thousand three hundred and twenty (70%) responded. Getting patients to alter their lifestyles was perceived as causing the most difficulty in managing individual patients, followed by lack of time, patients' nonattendance, noncompliance with medical regimens and poor communication with secondary care. The greatest barriers to practices providing desirable care were lack of time/under-funding and keeping up to date in the area of diabetes, followed by lack of space, inadequate chiropody, dietetics, ophthalmology and access to secondary care. There are important differences between HAs in the difficulties experienced by primary care teams and we have ranked the HAs accordingly.

CONCLUSION

The study has identified what problems need tackling in order to assist primary care to deliver good quality diabetes care, and has highlighted HAs where primary care needs further help, and HAs where examples of good practice may be found and useful lessons learnt. This should form the basis of a needs-based research and development programme for diabetes in primary care.

Risk and prevention of type II diabetes: offspring's views

BACKGROUND

People with a parent with type II diabetes have an increased risk of the disease. There is increasing evidence for the possibility of prevention, particularly by attaining and maintaining normal weight and adequate levels of physical exercise. No prior studies have reported awareness of risk and prevention in this high-risk group.

AIM

To explore beliefs about personal risk of diabetes and prevention in people with a parent with type II diabetes.

DESIGN OF STUDY

A total of 254 adults with type II diabetes were identified from five randomly selected practices in south London. Self-report questionnaires were sent to 152 eligible offspring of these patients. A total of 105 of the offspring returned the self-report questionnaires and participated in the study.

SETTING

Five randomly selected practices in south London.

METHODS

Patients with type II diabetes in five randomly selected practices in south London were asked if we might contact their offspring. One randomly selected offspring (over 18 years of age) from each family completed a self-report questionnaire.

RESULTS

Of 254 adults with type II diabetes 152 had eligible offspring. A total of 105 (69%) of the offspring participated in the study. A total of 69 (66%) of these offspring believed their personal risk of developing diabetes was 'low'. At least 28 (28%) and maybe as many as 73 (70%) underestimated the risk of diabetes in offspring. Compared with the number thinking their current risk was low significantly more (95 versus 69) thought that their risk would be low if neither of their parents had diabetes. Fifty-seven (54%) thought prevention was possible. Sixteen thought taking more exercise was important for prevention and only seven thought that weight control was important. Many had good general knowledge about diabetes and its complications but awareness of the relationship between diabetes and cardiovascular disease was poor.

CONCLUSIONS

People with a parent with type II diabetes are usually aware that they have an increased risk of diabetes. However, they often underestimate that risk and know little about potentially useful preventive strategies. They need accurate information about these matters if they are to reduce their risk of diabetes and its complications.

More good than harm: a randomised controlled trial of the effect of education about familial risk of diabetes on psychological outcomes

BACKGROUND

Offspring of people with type 2 diabetes underestimate their risk of developing the disease and know little about primary prevention. However, education about risk might cause psychological harm.

AIM

To examine cognitive and psychological effects of education about personal risk.

METHOD

Patients with type 2 diabetes were recruited from randomly selected general practices. One of their adult offspring was randomly selected and randomly allocated into one of three groups: 1. Group 1: given an initial interview, education, and a final interview; 2. Group 2: given an initial and final interview; and 3. Group 3: given one interview only. Psychological outcomes were assessed using Hospital Anxiety and Depression Scale (HAD) and Positive Well-Being Scale (PWB) scores.

RESULTS

Sixty-nine per cent (105/152) of eligible offspring participated. Ninety-one per cent (96/152) completed the study. Comparing first and final interviews, in Group 1, significantly fewer responders at final interview (after education) thought that their risk of developing diabetes was 'low' (65% versus 41%, P = 0.027), while in Group 2, there was no significant change in risk perception (P = 0.13). Significantly fewer people in the educated group (Group 1, final interview) than in the control group (Group 3) thought their risk of developing diabetes was 'low' (41% versus 77%, P = 0.002). Risk education did not affect total HAD scores or PWB scores significantly.

CONCLUSION

Educating offspring of people with type 2 diabetes in this way about their risk of diabetes and possible preventive strategies increases their perception of personal risk but does not cause psychological harm.

A survey of diabetes care in general practice in England and Wales

BACKGROUND

The focus of care for people with diabetes has shifted from hospital to general practice. Many practices now offer diabetes care via dedicated mini-clinics, shared care schemes or opportunistically. There has never been a national survey of the organisation of diabetes care in general practice.

AIM

To describe some key features of diabetes care in primary care in England and Wales.

METHOD

Descriptive postal questionnaire survey to one in five (1873) randomly sampled general practices.

RESULTS

Seventy per cent (1320) of practices responded. Of these, 96% had diabetes registers identifying 1.9% of their population as having diabetes; 71% held clinics run by a general practitioner (GP) and a nurse (64%) or a nurse alone (34%); 80% felt adequately supported; and 54% shared patient management protocols with the local secondary care team. Overall, practices provided most of the routine diabetes care for 75% of their diabetic patients. The majority of GPs and practice nurses had received some recent, albeit brief, diabetes education.

CONCLUSION

A large proportion of diabetes care now takes place in the community, much of it delivered by practice nurses. The organisational infrastructure necessary for delivering good care is in place. Many practices have a special interest in diabetes with the majority feeling adequately supported by secondary care. However, there are concerns about the educational needs of those providing care. More work needs to be done to ensure seamless care across the primary-secondary care interface.

The effects of acutely administered low dose sarin on cognitive behaviour and the electroencephalogram in the common marmoset

Previous studies have suggested that administration of a clinically sign-free dose of sarin to non-human primates gives rise to subtle changes in brain electrical activity as measured by electroencephalography (EEG) several months following exposure. The functional significances of such changes are unclear. The present study monitored EEG by using implantable radiotelemetry, and also assessed the performance of complex behavioural tasks, in non-human primates for up to 15 months following exposure to a low dose of sarin. Baselines of EEG and behaviour were shown to be stable over several months in control animals. The doses of sarin administered caused erythrocyte cholinesterase inhibitions of 36.4% to 67.1%. Overall, no significant changes in EEG patterns were observed although there were increases in beta 2 amplitude which approached significance (p=0.07). No deleterious effects on performance were seen on the touchscreen mediated discrimination tasks presented from the Cambridge Neuropsychological Test Automated Battery (CANTAB). This study illustrates the validity of the approach employed and makes an important contribution to the investigation of the long-term effects of organophosphorous compounds.

Synergism between sevoflurane and intravenous fentanyl on A delta and C somatosympathetic reflexes in dogs

In this study, we defined the nature of the interactions between sevoflurane and fentanyl on spontaneous and reflex-evoked sympathetic activity, resting heart rate (HR), and mean arterial pressure (MAP). Spontaneous renal sympathetic nerve activity (RSNA) and A delta- and C-fiber-mediated somatosympathetic reflexes, evoked by electrical stimulation of radial nerves, and HR and MAP were recorded in anesthetized dogs. In one group, the effects of incremental doses of 2-64 micrograms/kg fentanyl i.v. were observed. It had a greater inhibitory effect on C than on A delta reflexes, which were abolished by mean cumulative doses of 64 micrograms/kg and approximately 128 micrograms/kg, respectively. Although 1.5% sevoflurane reduced C reflexes by 28% and A delta reflexes by only 12%, it reduced the total doses of fentanyl required for their abolition to 32 micrograms/kg and 64 micrograms/kg, respectively. Mean RSNA, HR, and MAP values were reduced by 46%, 54%, and 30%, respectively, by fentanyl alone and by 23%, 11%, and 17%, respectively, in response to 1.5% sevoflurane. The combination of fentanyl and sevoflurane caused reductions of 44%, 54%, and 41%, respectively, which indicates a less than additive effect. These results indicate that sevoflurane interacts synergistically with fentanyl to depress A delta and C somatosympathetic reflexes, whereas for RSNA, HR, and MAP, their effects were less than the additive.

IMPLICATIONS

Although fentanyl caused a greater depression of C than of A delta reflexes to the point of abolition, the maximal depression of spontaneous sympathetic activity, heart rate, and arterial pressure occurred at smaller doses. The combined depressant effects of sevoflurane and fentanyl were synergistic on somatosympathetic reflexes but were less than additive on spontaneous sympathetic activity, heart rate, and arterial pressure.

Relationship between change in amniotic fluid index and volume of fluid removed at amnioreduction

OBJECTIVE

To determine the relationship between the change in amniotic fluid index (AFI) and the volume of fluid removed at amnioreduction.

METHODS

In a prospective study of 20 twin and 19 singleton pregnancies undergoing amnioreduction for severe polyhydramnios, AFI was measured immediately before and after the procedure and was correlated with the volume of fluid withdrawn.

RESULTS

A significant linear relationship was found between AFI change and the volume drained in all pregnancies (Y = -4.2X; R2 = 0.49; P = .002). This relationship was similar in singleton and twin pregnancies. However, there was a significant absolute difference in AFI change between singleton and twin pregnancies of 7.9 cm (95% confidence interval 0.41, 15.2; P = .04).

CONCLUSION

These findings support the use of the four-quadrant AFI as a semiquantitative index of amniotic fluid volume. This relationship can be used to predict the drainage volume required to achieve a target AFI with amnioreduction and thus avoid repeated AFI measurements during the procedure itself.

Assessment of total body water using bioelectrical impedance analysis in neonates receiving intensive care

AIMS

To determine the most suitable anthropometric and impedance measures and current frequency for the application of bioelectrical impedance to neonates receiving intensive care; and to derive predictive models for the estimation of total body water.

METHODS

Twenty eight babies (median gestational age 30.5 weeks, range 24-38; median birthweight 1.388 kg, range 0.690-3.510) were each studied once during the first week after birth. Total body water was first measured by the method of dilution of isotopic water (H218O). Bioelectrical measurements were made using the tetrapolar surface electrode method from four main distal limb positions (right hand-right foot; right hand-left foot; left hand-left foot; left hand-right foot), the left upper arm-left thigh position and the left scapula-right buttock position, and using six frequencies ((500, 250, 100, 50, 10 and 5 kHz). Regression models, to predict total body water, which were both independent and dependent of body weight on the day of study, were derived.

RESULTS

Resistance readings at 50 kHz obtained from the distal limb positions performed best. There was no difference between the distal limb positions. There was no difference in the goodness of fit of the models when using each of three indices of conductor length, foot, spine and sternum. The model total body water (litres) (TBW) = 0.016 + 0.674 body-weight(kg)-0.038 wt2 + 3.84 foot length (cm)2/resistance (50 kHz in OHMS) performed best, accounting for 99.5% of the variation in TBW, with a 95% prediction interval of 165 ml. The model TBW = 0.144 + 15.518 foot length (cm)2/resistance (50 kHz in ohms) accounted for 96.4% of the variation and had a 95% prediction interval of 420 ml.

CONCLUSIONS

Bioelectrical impedance analysis is a simple, non-invasive method of estimating total body water in neonates receiving intensive care. It can be applied to both the assessment of changes in body water and body composition.

Influence of respiratory distress syndrome on body composition after preterm birth

AIM

To observe changes in body composition during the first week after birth, in preterm neonates with and without respiratory distress syndrome (RDS), so as to be able to provide optimal fluid and energy intake.

METHODS

Twenty four babies with RDS and 19 healthy preterm babies, with gestational ages ranging from 26-36 weeks, were studied daily for the first week after birth. Total body water (TBW) was measured using bioelectrical impedance analysis. The babies were weighed daily and a record made of fluid and energy intake. Body solids were calculated as the difference between body weight and TBW.

RESULTS

There was a highly significant reduction in body weight by the end of the week, with the RDS babies losing more than the healthy babies (RDS 7.6%; non-RDS 3.7%). There was no significant difference in the amount of TBW at birth in the babies with and without RDS (RDS 85.1%; non-RDS 85.5%) and both groups lost the same amount of body water (RDS 10.9%; non-RDS 9.9%) by the end of the first week. The amount of total body water lost was unrelated to the volume of fluid administered. There was a loss of body solids during the first day in the RDS group, but, overall, there was a highly significant increase in both groups between birth and day 7, which was greater in the healthy babies (RDS 13.0%; non-RDS 42.7%).

CONCLUSIONS

Loss of body water after birth occurs to the same extent in healthy preterm neonates and in babies with RDS and is unrelated to the volume of fluid administered. Given adequate nutritional support, an increase in body solids can accompany early postnatal weight loss and begins almost immediately after birth, in both healthy preterm babies and babies with RDS.

Serum calcium, phosphorus and albumin levels in relation to the angiographic severity of coronary artery disease

Though calcium plays an important role in a number of biologic processes related to the pathogenesis of atherosclerosis, the relationship of serum calcium and phosphorus levels with the angiographic severity of coronary artery disease (CAD) is not known. We retrospectively studied 376 stable patients (age range 31-86 years, mean 59.2 +/- 10.5 years; 68% males) undergoing routine coronary angiography and related the angiographic severity of CAD with the serum levels of total and corrected calcium, phosphorus, albumin, total protein and bicarbonate. The primary variable studied was the number of vessels with haemodynamically significant disease. On univariate analysis, total serum calcium and serum albumin levels had a negative association with the number of vessels diseased (P = 0.046 and 0.057, respectively). Multiple regression analysis using age, sex, smoking, diabetes, hypertension, hyperlipidaemia, ethnicity and family history, in addition to serum calcium, phosphorus and albumin levels as the predictor variables, showed that serum albumin has an independent negative and serum phosphorus has an independent positive association with the angiographic severity of CAD (P = 0.04 and 0.003, respectively; n = 294). Serum phosphorus level also showed highly significant positive associations with the presence of total or subtotal occlusion and with most severe stenosis observed on angiography. A moderate change in the serum level of albumin or phosphorus confers a risk similar to that associated with smoking, as estimated by the odds ratios.

Estrous cycle phase variations in visceromotor and cardiovascular responses to colonic distension in the anesthetized rat

Visceromotor and cardiovascular responses to colonic distension were measured in female rats, anesthetized with halothane in oxygen, in the proestrus, estrus, metestrus and diestrus phases of the estrous cycle. Ten rats were studied in each group and responses were measured at 5-min intervals for 60 min. A mixed model analysis of variance showed that there was no real change in either the visceral or cardiovascular response with time. There was a highly significant difference in visceromotor responses between the phases of the estrous cycle (P < 0.001). During the phase of proestrus the balloon pressure at which a response was triggered was much lower, with a mean value (95% confidence interval) of 18.7 (16.1, 21.8) mmHg, than the other phases with mean values (95% confidence interval) of 31.9 (27.4, 37.2) mmHg for estrus, 28.1 (24.2, 32.8) mmHg for metestrus, and 31.1 (26.7, 36.3) mmHg for diestrus. The mean arterial blood pressure increased in all groups (range 3.2, 5.4%) as a response to the stimulus, but there was no associated heart rate variability and no significant differences in cardiovascular changes between the groups (P = 0.6). The visceromotor responses measured during the phase of proestrus occurred at a significantly lower threshold than in the other phases of estrous.

Effect of cell culture on rabbit colonic smooth muscle bradykinin receptors

The aim of this study was to assess the effect of cell culture on the bradykinin receptor of rabbit colon myocytes. In longitudinal muscle strips prepared from distal colon, bradykinin stimulated dose-dependent contraction that was 62% of the maximal response to bethanecol. At 4 degrees C, [3H]bradykinin binding to fresh muscle homogenates from the distal colon was time dependent, saturable, and linearly related to tissue concentration. Specific binding of 0.6 nmol/L [3H]bradykinin was 80% +/- 2% of total binding. In competitive binding studies, Hill coefficients approached unity, suggesting the presence of a single class of receptors. The order of potency was bradykinin greater than [D-Phe7]bradykinin much greater than des-Arg9, [Leu8]bradykinin, which is consistent with results of a B2 receptor subclass. Colon myocytes from the longitudinal muscle layer achieved confluence and were harvested for studies after 12-14 days in culture. Bradykinin receptors were of high affinity [disassociation constant (Kd) = 672 pmol/L] and numbered 10,217 +/- 2567/cell. To show that the receptors on cultured myocytes were functional, the effect of bradykinin was measured (a) on intracellular calcium concentration using Fura 2 and (b) on prostaglandin E2 concentration in the culture media using radioimmunoassay. In cells grown to confluence on cover slips and preloaded with Fura 2, bradykinin stimulated the threshold response at 1 nmol/L and maximal response (increased intracellular calcium concentration from 229 to 633 nmol/L) at 1 mumol/L. Bradykinin, 100 nmol/L, increased Prostaglandin E2 in the culture media threefold. In summary, colon myocytes express functioning bradykinin receptors, which, unlike muscarinic receptors, persist in culture. Bradykinin appears to be a suitable agonist for studies of receptor-mediated intracellular events in cultured colon myocytes.

Structural characterization of calcitonin gene-related peptide purified from rabbit intestine

Calcitonin gene-related peptide (CGRP) immunoreactive material has been found in extracts of the intestine, however, the structure of intestinal CGRP is not known. Analytical reverse phase HPLC and ion-exchange FPLC revealed one predominant immunoreactive CGRP peak in rabbit intestinal extracts. This material was purified from rabbit intestine by sequential steps of reverse phase HPLC and ion-exchange FPLC. Microsequence and mass spectral analysis of the purified peptide and its chymotryptic fragments were consistent with the structure: GCNTATCVTHRLAGLLSRSGGMVKSNFVPTNVGSEAF-amide. Rabbit intestinal CGRP is identical to human CGRP-II in 35 of 37 amino acid residues. Two amino acid differences were detected at position 1, with Gly in rabbit CGRP instead of Ala in human CGRP-II, and at position 35, with Glu instead of Lys, respectively. Rabbit CGRP differed from human CGRP-I by three additional amino acids at positions 3, 22, and 25. This report shows that a CGRP form which closely resembles human CGRP-II, by means of chemical characterization, is the predominant form in rabbit intestine. Rabbit CGRP is the only CGRP form which has Gly as the amino terminal amino acid. Since the amino terminus of CGRP seems to be important for expression of bioactivity, the biological activity of rabbit CGRP may differ from human, rat and porcine CGRP.