In-Hospital Formula Supplementation in Appalachian Women Intending to Exclusively Breastfeed

OBJECTIVE

In-hospital formula supplementation places infants at risk for early breastfeeding cessation. The study's aim was to identify predictive and protective factors for in-hospital formula supplementation in individuals documented as wanting to exclusively breastfeed and residing in a geographic region with adverse social determinants of health and low breastfeeding rates. Additionally, we wished to determine if lactation consultation served as a protective factor against supplementation.

METHODS

In this cross-sectional study, we retrospectively reviewed 500 randomly selected charts of newborns born in a 12 month period at a regional tertiary care hospital. We included healthy, full-term neonates having a recorded maternal decision to exclusively breastfeed. Maternal-newborn dyad characteristics were compared between those exclusively breastfeeding and those with in-hospital formula supplementation.

RESULTS

Of the 500 charts, 70% of individuals desired to exclusively breastfeed. Overall, 41% of breastfed newborns were supplemented with formula before discharge, and 32% of women met with lactation consultants prior to supplementation. No statistically significant association was present between exclusive breastfeeding at discharge and meeting with a hospital lactation consultant (p = 0.55). When controlling for the confounders of maternal demographics and lactation consultation, significant associations with formula supplementation included Cesarean delivery (odd ratio: 2.08, 95% confidence interval: 1.04-4.16), primiparity (2.48, 1.27-4.87), and high school level of education (2.78, 1.33-5.78).

CONCLUSIONS

Maternal characteristics of high school level educational, primiparity, and Caesarean delivery place individuals at risk for in-hospital formula supplementation in individuals wishing to exclusively breastfeed. Addressing barriers to exclusive breastfeeding is essential to enhance maternal and newborn health equity.

Evaluation of QSAR models for predicting mutagenicity: outcome of the Second Ames/QSAR international challenge project

Quantitative structure-activity relationship (QSAR) models are powerful in silico tools for predicting the mutagenicity of unstable compounds, impurities and metabolites that are difficult to examine using the Ames test. Ideally, Ames/QSAR models for regulatory use should demonstrate high sensitivity, low false-negative rate and wide coverage of chemical space. To promote superior model development, the Division of Genetics and Mutagenesis, National Institute of Health Sciences, Japan (DGM/NIHS), conducted the Second Ames/QSAR International Challenge Project (2020-2022) as a successor to the First Project (2014-2017), with 21 teams from 11 countries participating. The DGM/NIHS provided a curated training dataset of approximately 12,000 chemicals and a trial dataset of approximately 1,600 chemicals, and each participating team predicted the Ames mutagenicity of each trial chemical using various Ames/QSAR models. The DGM/NIHS then provided the Ames test results for trial chemicals to assist in model improvement. Although overall model performance on the Second Project was not superior to that on the First, models from the eight teams participating in both projects achieved higher sensitivity than models from teams participating in only the Second Project. Thus, these evaluations have facilitated the development of QSAR models.

Beyond image defined risk factors (IDRFs): a delphi survey highlighting definition of the surgical complexity index (SCI) in neuroblastoma

PURPOSE

Preoperative evaluation of Image Defined Risk Factors (IDRFs) in neuroblastoma (NB) is crucial for determining suitability for upfront resection or tumor biopsy. IDRFs do not all carry the same weighting in predicting tumor complexity and surgical risk. In this study we aimed to assess and categorize a surgical complexity (Surgical Complexity Index, SCI) in NB resection.

METHODS

A panel of 15 surgeons was involved in an electronic Delphi consensus survey to identify and score a set of shared items predictive and/or indicative of surgical complexity, including the number of preoperative IDRFs. A shared agreement included the achievement of at least 75% consensus focused on a single or two close risk categories.

RESULTS

After 3 Delphi rounds, agreement was established on 25/27 items (92.6%). A severity score was established for each item ranging from 0 to 3 with an overall SCI range varying from a minimum score of zero to a maximum score of 29 points for any given patient.

CONCLUSIONS

A consensus on a SCI to stratify the risks related to neuroblastoma tumor resection was established by the panel experts. This index will now be deployed to critically assign a better severity score to IDRFs involved in NB surgery.

Ruptured Ovarian Cyst Masking Diagnosis of Hernia Through Broad Ligament of Uterus: A Case Report

Small bowel obstruction is a common surgical emergency and frequent cause of hospitalization. Internal hernias account for less than 6% of all small bowel obstruction cases. Less frequently, hernias through the broad ligament of the uterus can occur and account for only 4-7% of total internal hernia cases. We report a case of a small bowel hernia through broad ligament of the uterus in a young female. Multiple diagnostic modalities suggested a ruptured ovarian cyst as the most probable cause for her abdominal pain. However, her symptoms were much more severe than an ovarian cyst would normally produce. Therefore, a diagnostic laparotomy was performed, which found a small intestine hernia through the left broad ligament of the uterus. The diagnosis of intestinal hernias, specifically through the broad ligament, is often delayed due to the infrequent occurrence, varied presentation, and difficulty of confirmation on computed tomography (CT) scan. Surgery is the gold standard for the diagnosis and treatment of internal hernias. This article draws attention toward a rare and potentially life-threatening cause of abdominal pain.

Sexual function, quality of life, and fertility in women who had surgery for neonatal Hirschsprung's disease

The authors explore multi-domain outcomes in a cross-sectional cohort study of patients with Hirschsprung's Disease. They identify hitherto unrecognised issues affecting sexual function and fertility specifically in female patients.

A nurse staffing model for an unprecedented event

Lessons learned from one hospital's COVID-19 experience.

Thoracoscopic oesophageal atresia/tracheo-oesophageal fistula (OA/TOF) repair is associated with a higher stricture rate: a single institution’s experience

PURPOSE

Thoracoscopic OA/TOF repair was first described in 1999. Currently, less than 10% of surgeons routinely employ minimally access surgery. Our primary aim was to review our immediate-, early- and long-term outcomes with this technique compared with the open approach.

METHODS

A retrospective review of all patients undergoing primary OA/TOF (Type C) repair at our institution from 2009 was conducted. Outcome measures included length of surgery, conversion rate from thoracoscopy, early complications such as anastomotic leak and post-operative complications such as anastomotic strictures needing dilatations. Fisher's exact and Kruskal-Wallis tests were used for statistical analysis.

RESULTS

95 patients in total underwent OA/TOF repair during the study period of which 61 (64%) were completed via an open approach. 34 were attempted thoracoscopically of which 11 (33%) were converted. There was only one clinically significant anastomotic leak in our series that took place in the thoracoscopic group. We identified a significantly higher stricture rate in our thoracoscopic cohort (72%) versus open surgery (43%, P < 0.05). However, the median number of dilations (3) performed was not significantly different between the groups. There was one recurrent fistula in the thoracoscopic converted to open group. Our median follow-up was 60 months across the groups.

CONCLUSION

In our experience, the clinically significant leak rate for both open and thoracoscopic repair as well as recurrent fistula is much lower than has been reported in the literature. We do not routinely perform contrast studies and are, thus, reporting clinically significant leaks only. The use of post-operative neck flexion, ventilation and paralysis is likely to be protective towards a leak. Thoracoscopic OA/TOF repair is associated with a higher stricture rate compared with open surgery; however, these strictures respond to a similar number of dilatations and are no more refractory. Larger, multicentre studies may be useful to investigate these finding further.

The multi-disciplinary management of complex congenital and acquired tracheo-oesophageal fistulae

AIM OF THE STUDY

Complex tracheo-oesophageal fistulae (TOF) are rare congenital or acquired conditions in children. We discuss here a multidisciplinary (MDT) approach adopted over the past 5 years.

METHODS

We retrospectively collected data on all patients with recurrent or acquired TOF managed at a single institution. All cases were investigated with neck and thorax CT scan. Other investigations included flexible bronchoscopy and bronchogram (B&B), microlaryngobronchoscopy (MLB) and oesophagoscopy. All cases were subsequently discussed in an MDT meeting on an emergent basis if necessary.

MAIN RESULTS

14 patients were referred during this study period of which half had a congenital aetiology and the other half were acquired. The latter included button battery ingestions (5/7) and iatrogenic injuries during oesophageal atresia (OA) repair. Surgical repair was performed on cardiac bypass in 3/7 cases of recurrent congenital fistulae and all cases of acquired fistulae. Post-operatively, 9/14 (64%) patients suffered complications including anastomotic leak (1), bilateral vocal cord paresis (1), further recurrence (1), and mortality (1). Ten patients continue to receive surgical input encompassing tracheal/oesophageal stents and dilatations.

CONCLUSIONS

MDT approach to complex cases is becoming increasingly common across all specialties and is important in making decisions in these difficult cases. The benefits include shared experience of rare cases and full access to multidisciplinary expertise.

Esophageal atresia and malrotation: what association?

INTRODUCTION

Esophageal atresia/tracheo-esophageal fistula (EA/TEF) has an incidence of approximately 1:3,500. The incidence of malrotation is thought to be 1:200-500. We attempted to define the incidence of a combination and discuss the implications.

METHODS

This was a retrospective review of all patients admitted to a single institution with a diagnosis of EA or EA/TEF or TEF between April 1981 and January 2013. Patients were included if the position of the duodeno-jejunal flexure (DJF) was determined by upper GI contrast study (UGIS), surgery or post-mortem.

RESULTS

Case notes were reviewed for 235 patients. In the EA type A group, 3/28 (11 %; 95 % CI 3.7-27.2 %) had malrotation, significantly higher than the reported incidence of malrotation in the general population (p = 0.0008). All three patients in this group were symptomatic with one patient found to have a volvulus at emergency surgery. In the type C group, 6/196 (3 %, 95 % CI 1.4-6.5 %) had malrotation, significantly higher than the incidence reported for the general population (p = 0.0033) but not significantly different to that of the type A group (p = 0.0878). There were no patients with malrotation identified in any other EA/TEF type. In total, 9/235 (3.8 %; 95 % CI 2.0-7.2 %) patients with EA had malrotation, significantly higher than the 5/1,050 (0.48 %) reported for the general population (p = 0.0002).

CONCLUSION

There is a high incidence of malrotation in patients with pure EA. In the type A group an attempt to identify the DJF position at gastrostomy siting and/or performance of UGIS in the neonatal period should be undertaken. There should also be a low threshold for UGIS in all EA/TEF patients.

ToxML, a data exchange standard with content controlled vocabulary used to build better (Q)SAR models

Development of accurate quantitative structure-activity relationship (QSAR) models requires the availability of high quality validated data. International regulations such as REACH in Europe will now accept (Q)SAR-based evaluations for risk assessment. The number of toxicity datasets available for those wishing to share knowledge, or to use for data mining and modelling, is continually expanding. The challenge is the current use of a multitude of different data formats. The issues of comparing or combining disparate data apply both to public and proprietary sources. The ToxML project addresses the need for a common data exchange standard that allows the representation and communication of these data in a well-structured electronic format. It is an open standard based on Extensible Markup Language (XML). Supporting information for overall toxicity endpoint data can be included within ToxML files. This makes it possible to assess the quality and detail of the data used in a model. The data file model allows the aggregation of experimental data to the compound level in the detail needed to support (Q)SAR work. The standard is published on a website together with tools to view, edit and download it.

Advanced necrotizing enterocolitis part 2: recurrence of necrotizing enterocolitis

AIM OF THE STUDY

The aim of this study was to report incidence and clinical outcomes of recurrent necrotizing enterocolitis (NEC).

METHODS

Review of infants treated for recurrent episode(s) of NEC at a tertiary Neonatal Surgical Intensive Care Unit over 8 years (January 2002 to February 2011). Demographic, clinical, radiological, and operative data were analyzed and compared using Mann-Whitney or Fisher's exact tests. Data are reported as median (range).

RESULTS

A total of 212 consecutive infants were referred for surgical evaluation and treatment of NEC (Bell stage II or III). Of these patients, 22 (10%) had suspected recurrent NEC: in 11 of these the primary episode was Bell stage I successfully treated before coming to our institution (suspected recurrent NEC); in the remaining 11, the primary episode was confirmed (Bell stage II or III) NEC successfully treated in our hospital. Birth weight, gestational age at birth, corrected gestational age, weight on admission, gender, need for surgery, stricture, and mortality rates were similar between infants with recurrent NEC and those with a single episode. Long-term parenteral nutrition (PN) dependency (>28 days) was significantly more common following recurrent NEC compared with a single episode. Among the infants with recurrent NEC, medical therapy alone was not successful in the majority (82%) of cases during the first episode and all required surgery during the recurrent episode.

CONCLUSION

Infants (10%) referred for surgical treatment of NEC develop recurrence of the disease. Surprisingly, these infants have similar mortality and stricture rates to those with a single episode. However, the incidence of long-term PN dependency was significantly increased in those with recurrent episodes of NEC.

Fundoplication in ventilator-dependent infants with gastro-oesophageal reflux

AIM

In ventilator-dependent infants with complex comorbidities, severe gastro-oesophageal reflux (GOR) may contribute to prolonging the period of ventilation. It is often difficult to predict whether antireflux surgery will improve the respiratory status of an infant and assist with weaning off the ventilator. The aim of this study was to review the outcomes in a cohort of ventilator-dependent infants who underwent fundoplication to help wean them off ventilation.

METHODS

Between January 2006 and December 2010, out of 596 infants who underwent fundoplication for symptoms of GOR, 26 were ventilator dependent before surgery; 13 patients had an emergency fundoplication following an acute life-threatening event (n = 5, 19%) or an acute deterioration of respiratory status (n = 8, 31%). Fundoplication was planned in the rest of the group (n = 13, 50%) with the aim of improving respiratory status and weaning from ventilation. The median age at surgery was 5.8 months (range: 0.8 to 19.4 months). The median weight at surgery was 6.3 kg (range: 4 to 15.1 kg). Data were collected for each infant on comorbidities, pre- and postoperative ventilation status, pre- and postoperative GOR symptoms, and survival.

RESULTS

All infants underwent a Nissen fundoplication with no intraoperative morbidity or mortality. Of these, 12 infants had a laparoscopic fundoplication; 14 infants had an open fundoplication. Postoperatively, all infants received invasive positive pressure ventilation in the intensive care unit (ICU). All infants were successfully weaned from ventilation. The median time to extubation was 4 days (range: 2 to 18 days). The median postoperative ICU stay was 9 days (range: 3 to 52 days). Of the patients, 9 (34%) had a recurrence of symptoms following fundoplication; 5 (19%) subsequently underwent revision of fundoplication and 1 (3.8%) underwent oesophago-gastric dissociation; and 10 (38%) died within the study period.

CONCLUSION

In infants with severe GOR, ventilator dependence, and complex comorbidities, fundoplication may be a useful procedure to assist weaning off ventilator dependence. Rates of symptom recurrence, of revision of fundoplication, and of mortality within this cohort were higher than expected. These data reflect the challenges of patient selection in high-risk groups.

Effectiveness of the antegrade colonic enema stopper at preventing stomal stenosis: long-term follow-up

AIM OF THE STUDY

Stomal stenosis is the commonest complication of the antegrade colonic enema (ACE) procedure, reportedly occurring in 25-55% of patients. As such, a simple ACE stopper device (a small silicone plug sited in the ACE conduit between catheterisations) was designed to prevent stenosis. We performed a long-term follow-up study to determine the effectiveness of the stopper device.

METHODS

A retrospective case note review was performed of all patients who successfully underwent a primary ACE procedure over an 8.5-year period (January 2002 to June 2010). The inclusion criteria were (i) a minimum of 6 months follow-up, (ii) simple appendicostomy, (iii) caecal/colonic flap. In all patients an ACE stopper was sited in the conduit for at least 4 months and removed only for catheterisation. Data are mean±SEM.

MAIN RESULTS

38 children were included in our study. Mean age at surgery was 9.6±0.5 years. Surgery was performed in 22 patients for incontinence and in 16 for chronic constipation. 31 underwent an appendicostomy and 7 had a caecal/colonic flap; all received an ACE stopper. The mean follow-up was 2.6±0.3 years. Only 3 patients (8%) developed stomal stenosis. The first occurred 6 months postoperatively, resulting from an ACE stopper which was too small and consequently persistently fell out. This conduit required dilatation. The second occurred at 27 months secondary to a stomal infection and required surgical revision. The third occurred 8 months postoperatively for no obvious cause, and was treated with dilation. 1 patient experienced stomal leakage.

CONCLUSION

The ACE stopper is a simple yet highly effective method of preventing stomal stenosis. We recommend using the stopper in all ACE patients.

Advanced necrotizing enterocolitis part 1: mortality

AIM OF THE STUDY

The aim of this study was to investigate the factors associated with mortality in infants referred for the surgical treatment of advanced necrotizing enterocolitis (NEC).

METHODS

Retrospective review of all infants with confirmed (Bell stage II or III) NEC treated in our unit during the past 8 years (January 2002 to December 2010). Data for survivors and nonsurvivors were compared using Mann-Whitney test and Fisher's exact test and are reported as median (range).

RESULTS

Of the 205 infants with NEC, 35 (17%) were medically managed; 170 (83%) had surgery; 66 (32%) infants died; all had received surgery. Survivors and nonsurvivors were comparable for gestational age, birth weight, and gender distribution. Overall mortality was 32%, the highest mortality was in infants with pan-intestinal disease (86%) but remained significant in those with less severe disease (multifocal 39%; focal disease 21%). The commonest cause of mortality was multiple organ dysfunction syndrome and nearly half of the nonsurvivors had care withdrawn.

CONCLUSION

Despite improvement in neonatal care, overall mortality (32%) for advanced NEC has not changed in 10 years. Mortality is significant even with minimal bowel involvement.

A phase I study of the nitroimidazole hypoxia marker SR4554 using 19F magnetic resonance spectroscopy

Background:

SR4554 is a fluorine-containing 2-nitroimidazole, designed as a hypoxia marker detectable with ¹⁹F magnetic resonance spectroscopy (MRS). In an initial phase I study of SR4554, nausea/vomiting was found to be dose-limiting, and 1400 mg m⁻² was established as MTD. Preliminary MRS studies demonstrated some evidence of ¹⁹F retention in tumour. In this study we investigated higher doses of SR4554 and intratumoral localisation of the ¹⁹F MRS signal.

Methods:

Patients had tumours ⩾3 cm in diameter and ⩽4 cm deep. Measurements were performed using ¹H/¹⁹F surface coils and localised ¹⁹F MRS acquisition. SR4554 was administered at 1400 mg m⁻², with subsequent increase to 2600 mg m⁻² using prophylactic metoclopramide. Spectra were obtained immediately post infusion (MRS no. 1), at 16 h (MRS no. 2) and 20 h (MRS no. 3), based on the SR4554 half-life of 3.5 h determined from a previous study. ¹⁹Fluorine retention index (%) was defined as (MRS no. 2/MRS no. 1)*100.

Results:

A total of 26 patients enrolled at: 1400 (n=16), 1800 (n=1), 2200 (n=1) and 2600 mg m⁻² (n=8). SR4554 was well tolerated and toxicities were all ⩽grade 1; mean plasma elimination half-life was 3.7±0.9 h. SR4554 signal was seen on both unlocalised and localised MRS no. 1 in all patients. Localised ¹⁹F signals were detected at MRS no. 2 in 5 out of 9 patients and 4 out of 5 patients at MRS no. 3. The mean retention index in tumour was 13.6 (range 0.6–43.7) compared with 4.1 (range 0.6–7.3) for plasma samples taken at the same times (P=0.001) suggesting ¹⁹F retention in tumour and, therefore, the presence of hypoxia.

Conclusion:

We have demonstrated the feasibility of using ¹⁹F MRS with SR4554 as a potential method of detecting hypoxia. Certain patients showed evidence of ¹⁹F retention in tumour, supporting further development of this technique for detection of tumour hypoxia.

Undertaking procedure-based assessment is feasible in clinical practice

INTRODUCTION

With the development of a new curriculum, workplace based assessments such as procedure-based assessment (PBA) are becoming increasingly common within surgical training. However, there have been concerns about the impact of these assessments on clinical practice. This study assessed the time taken to complete PBA forms to determine whether it is feasible in clinical practice.

MATERIALS AND METHODS

PBAs for three colorectal procedures (anterior resection, right hemicolectomy and anal fistula) were undertaken by various trainers and trainees. A pilot study was performed to identify potential reasons for incomplete forms and procedural modifications subsequently applied in the main study. Times taken to complete the consenting and operative components of the forms were recorded.

RESULTS

Incomplete forms in the pilot were mainly attributable to time constraints. In the main study, all assessments were completed within 30 min. Assessment times increased with complexity of the procedure. Median times for completing the consenting and operative components in anterior resection were 13 min (range, 8-15 min) and 15 min (range, 10-18 min), respectively.

CONCLUSIONS

PBAs are feasible in clinical practice and are valued by trainees as a means of enabling focused feedback and targeted training. Commitment from trainers and trainees will be required but, with adequate planning, the assessment tool is effective with minimal impact on clinical practice.

Influence of environmental chemicals on drug therapy in humans: studies with contraceptive steroids

The effects have been studied of various environmental factors on the variability in response to oral contraceptive steroid therapy in women. Ten- to thirty-fold variations in plasma concentrations of norethisterone, L-norgestrel and ethinyloestradiol have been shown in samples taken 12 h after administration of oral contraceptives in mid-menstrual cycle. Factors shown to be responsible for this variation include passage into the enterohepatic circulation, a variable first-pass effect, and changes in metabolism in the gut wall or liver due to diet, disease, smoking or administration of drugs. Phenobarbitone and the antibiotic rifampicin increase both oestrogen and progestogen metabolism in women and in experimental animals by increasing hepatic and gut wall metabolism. In animals, other antibiotics (ampicillin, neomycin and lincomycin) suppress the gut flora that normally hydrolyse steroid conjugates excreted in bile; enterohepatic circulation or oral contraceptive steroids is thus reduced and their plasma concentrations lowered by up to 90%. In the human, ampicillin has a variable but less dramatic effect on elimination of oral contraceptives. Samples of gut wall mucosa obtained from patients with coeliac disease are defective in their ability to metabolize oral contraceptives. Cigarette smokers eliminate ethinyloestradiol more rapidly than non-smokers; an increased production of reactive steroid metabolites may thus be a cause of vascular disease in women who smoke and take contraceptive steroids.

Laparoscopic appendicectomy: a training model for laparoscopic right hemicolectomy?

OBJECTIVE

To analyse the outcome of laparoscopic appendicectomy and right hemicolectomy and see if the surgical approach to the former can be applied to the latter.

METHOD

A prospective electronic laparoscopic database identified 330 appendicectomies and 78 right hemicolectomies (using this approach) between 1996 and 2005.

RESULTS

Three hundred and thirty patients (188 males: median age 38 years, range 17-74 years) underwent laparoscopic appendicectomy; 270 (82%) were performed by trainees (higher surgical trainee 71%, basic surgical trainee 12%). The median operative time for trainees was 35 min (14-75 min) with a conversion rate 2%. There were no intra-operative complications. The postoperative complication rate excluding minor wound infection (5.5%) was 1.5%. There were no deaths. The median hospital stay was 2 days (1-15 days). The 30-day readmission rate was 1%. Seventy-eight patients (23-93 years) underwent laparoscopic right hemicolectomy during 2004/5; trainees performed parts thereof in the majority or all of the surgery in 25 cases. The median operation time was 55 min: trainees 115 (65-145 min). There was one conversion. The median hospital stay was 4 days (2-23 days) falling to 3 for the last 20 operations (1-8 days). There were two readmissions for wound sepsis and small bowel obstruction and three deaths (3.8%): anastomotic leak (one), C difficile infection leading to renal failure (one) and duodenal perforation (one).

CONCLUSION

Laparoscopic appendicectomy is a safe, predictable, easily learnt operation and an ideal model for learning the skills and principles required for more advanced laparoscopic colorectal interventions and in particular, right hemicolectomy.

Patterns of neuropsychological impairment in frontotemporal dementia

OBJECTIVE

To differentiate frontotemporal dementia (FTD) subtypes from each other and from probable Alzheimer disease (AD) using neuropsychological tests.

METHODS

Patients with FTD and AD (n = 109) were studied with a comprehensive neuropsychological protocol at first contact. Data were subjected to a principal components analysis (PCA) to extract core neuropsychological features. A five-factor solution accounted for 72.89% of the variance and yielded factors related to declarative memory, working memory/visuoconstruction, processing speed/mental flexibility, lexical retrieval, and semantic memory.

RESULTS

Between- and within-group analyses revealed that patients with AD obtain their lowest scores on tests of declarative memory while semantic dementia (SemD) patients are particularly disadvantaged on tests of semantic memory. On tests of processing speed/mental flexibility time to completion was faster for social comportment/dysexecutive (SOC/EXEC) patients, but these patients made more errors on some tests. Patients with corticobasal degeneration (CBD) and progressive nonfluent aphasia (PNFA) were impaired on tests of working memory. Logistic regression analyses using factor scores successfully assigned FTD subgroups and AD patients into their respective diagnostic categories.

CONCLUSION

Patients with differing frontotemporal dementia phenotypes can be distinguished from each other and from Alzheimer disease using neuropsychological tests.

Influenza fusion peptides

The 'fusion peptides' of a group of enveloped viruses that includes influenza, paramyxo-, retro-and filo-viruses are N-terminal regions of their membrane fusion proteins generated by cleavage of non-functional precursors. For the influenza membrane fusion protein, haemagglutinin (HA), the three-dimensional structures of precursor HA, cleaved HA and fusion-activated HA show that the fusion peptides are located in different positions in all three forms and adopt different structures. Analyses of mutant HAs with changes in fusion peptide sequence indicate the importance of specific residues for membrane-fusion activity and suggest a structure for the fusion peptide in a fusion-active molecule.

Solution structure of the B-chain of insulin as determined by 1H NMR spectroscopy. Comparison with the crystal structure of the insulin hexamer and with the solution structure of the insulin monomer

The solution structure of the isolated B-chain of bovine insulin has been determined by 1H NMR spectroscopy combined with simulated annealing calculations. Complete sequence-specific assignments for the proton resonances are reported together with a set of 309 NOEs used in the structure calculations. Chemical-shift variations from random coil values provide support for the existence of helical regions in the polypeptide chain, as do a characteristic series of d alpha beta(i, i + 3) NOEs from residues B8 to B17. While there is some evidence for a limited degree of conformational averaging over the helical region, in general the helix is relatively well defined and corresponds closely to the helical region seen in the X-ray crystal structure of the insulin hexamer. Other similarities with the crystal structure include turn-like conformations at the carboxy terminal end of the helix and extended strands at both the amino and carboxy termini of the peptide. These similarities between the crystal structure and the isolated B-chain suggest that this peptide has intrinsic folding properties, which allow it to adopt its characteristic structure in intact insulin without the need for extensive cooperative interactions with the A-chain. Despite these general similarities, an important difference between the isolated B-chain and the intact protein occurs in the carboxy terminal region. This region appears significantly more mobile in the isolated B-chain. As a conformational change involving the carboxy terminus has been implicated in receptor binding, the current study of the isolated B-chain provides valuable information on the extent of this region's intrinsic mobility.

1H-n.m.r. study of the solution properties and secondary structure of neurotoxin III from the sea anemone Anemonia sulcata

The solution properties, secondary structure and global fold of the 27-residue polypeptide neurotoxin III (ATX III), from the sea anemone Anemonia sulcata, have been investigated using high-resolution 1H-n.m.r. spectroscopy. Studies of the concentration dependence of the n.m.r. spectrum indicate that the molecule self-associates in the millimolar concentration range useable for n.m.r. analysis, the association being less pronounced at acidic pH values. The dependence on pH of association implies that electrostatic interactions play a role in this process, while the significant concentration-dependent shifts of the aromatic resonances of Tyr-7 and Trp-13 indicate that hydrophobic interactions also contribute. Individual pKa values have been determined for most ionizable groups in the molecule. Sequence-specific resonance assignments were obtained for all protons using a range of two-dimensional homonuclear-correlated and nuclear-Overhauser-effect (nOe) spectra. The secondary structure of the polypeptide was identified from sequential (i, i+1) and medium-range (i, i+2/3/4) nOe connectivities, NH to C alpha H coupling constants, C alpha H chemical shifts, and the location of slowly exchanging backbone-amide protons. ATX III contains no regular alpha-helix or beta-sheet, consisting instead of a network of reverse turns. nOe connectivities between half-cystine residues are consistent with the disulphide pairings 3-17, 4-11 and 6-22. ATX III has a well-defined structure and appears to lack the disordered loop which, in the longer sea anemone toxins (46-49 residues), may be part of the receptor-binding surface.

An examination of practice referral rates in relation to practice structure, patient demography and case mix

This paper examines the variation in practice referral rates from 53 practices over a twelve-month period. Data from the Second National Morbidity Study were used in relation to practice structure; age, sex and Social Class composition of the patient population; and the case mix by practice. The results show that the age of the patient is an important determinant of the probability of referral, whereas Social Class has little influence. Analysis of the practice-based data showed that practices were highly concordant in their referral activity across sex and age (greater or less than 45 years), sex and Social Class (manual or non-manual), and across chapters of the disease classification. This degree of concordance points to characteristics of the practices rather than patients, and their problems as the main source of variation in practice referral behaviour.

The measurement of referrals for practice audit

The Royal College of General Practitioners and the Office of Population Censuses and Surveys have collaborated in three national studies of morbidity in general practice at approximately ten-year intervals. This paper presents data derived from the second survey conducted in 1970/71. A comparison of practice referral rates based on different measures is reported, and consideration given to the consequences of the choice of measure on how practices may be perceived. The findings of this study emphasise the need for caution in the interpretation of practice referral data while providing encouragement for general practitioners to engage in open peer review of their practice activities.

Accidental hydrocarbon ingestion cases telephoned to a regional poison center

One hundred eighty-four telephone calls to the Texas State Poison Center concerning accidental hydrocarbon ingestion were reviewed in an attempt to define the risk of developing any subsequent medical problem requiring therapeutic intervention. Special attention was given to changing symptom severity in an attempt to evaluate its usefulness in predicting future complications. One hundred twenty patients (65%) had no initial symptoms and remained asymptomatic throughout an 18-hour follow-up period. Sixty-two (34%) of patients had symptoms initially but quickly became asymptomatic. Two (1%) developed significant complications (one chemical pneumonitis, one death). These data suggest that the risk of significant complications after accidental hydrocarbon ingestion is low (approximately 1% of patients at risk). Patients who are asymptomatic or who quickly become asymptomatic can be watched safely at home, and referral of asymptomatic patients to a hospital may be unwarranted.