The South African National Non-Natural Mortality Surveillance System--rationale, pilot results and evaluation

BACKGROUND

While individual mortuaries have recorded data for non-natural deaths in time-limited studies, there have been no systematic efforts to draw forensic-medical services and state mortuaries into a nationwide fatal injury surveillance system. Beginning in June 1998, the National Non-Natural Mortality Surveillance System (NMSS) commenced pilot operation.

OBJECTIVE

To evaluate the NMSS and illustrate its utility from sample findings.

DESIGN

Data entered into the system by mortuary staff were checked against a random sample of cases for which separate forms were completed by an independent researcher. Process observations and follow-up with data users were used to assess the system's acceptability, timeliness and data usefulness.

SETTING

Eighteen mortuaries in six provinces representing approximately 35,000 cases per year, or around 50% of all non-natural deaths.

PARTICIPANTS

The National Departments of Health; Safety and Security; and Arts, Culture, Science and Technology; national and provincial forensic medico-legal services; the South African Police Services; universities and science research councils.

MAIN OUTCOME MEASURES

Surveillance system simplicity, flexibility, acceptability, sensitivity, positive predictive value, representativeness, timeliness, data usefulness and resources.

RESULTS

The NMSS was established at 10 target sites. Lack of equipment, personnel resistance, and closure of some mortuaries prevented implementation in the remaining eight mortuaries. Sensitivity was internally assessed and ranged from 65% to 95% for manner of death. Positive predictive value was also internally measured, and ranged from 74% to 80% for manner of death and from 71% to 82% for mechanism of death. Timeliness was good, and basic reports covering most items were available 6 weeks after a case had been examined. While staff found the system simple, acceptability depended on the individuals involved at different mortuaries, and the system was compromised to some extent by bureaucratic barriers. End users found the data to be of great value. NMSS set-up costs totalled approximately R26,000 per mortuary, and it is estimated that maintenance costs will be R8.00 per case registered.

CONCLUSIONS

With minimal resources, the NMSS uses existing investigative procedures to describe and report the epidemiology of fatal injuries. The pilot study demonstrates the feasibility of the system, and identifies the need to remove organisational constraints and individual barriers if it is to be sustained and expanded beyond the pilot sites.

A molecular analysis of dietary diversity for three archaic Native Americans

DNA was extracted from three fecal samples, more than 2,000 years old, from Hinds Cave, Texas. Amplification of human mtDNA sequences showed their affiliation with contemporary Native Americans, while sequences from pronghorn antelope, bighorn sheep, and cottontail rabbit allowed these animals to be identified as part of the diet of these individuals. Furthermore, amplification of chloroplast DNA sequences identified eight different plants as dietary elements. These archaic humans consumed 2-4 different animal species and 4-8 different plant species during a short time period. The success rate for retrieval of DNA from paleofeces is in strong contrast to that from skeletal remains where the success rate is generally low. Thus, human paleofecal remains represent a source of ancient DNA that significantly complements and may in some cases be superior to that from skeletal tissue.

Co-existence of lysosomal storage diseases in a consanguineous family

Lysosomal storage diseases are rare and coexistence of more than one in a family can present a diagnostic challenge as illustrated by this study. The index case born to consanguineous Asian parents presented with developmental delay. Investigations led to an incidental finding of Fabry disease. After numerous additional investigations over a year, a second diagnosis of aspartylglucosaminuria (AGU) was made. A family history of renal disease and developmental delay was disclosed. The sister and first cousin of the index case were diagnosed as homozygous for AGU, but do not have Fabry disease. The younger brother has since been diagnosed with both Fabry disease and AGU. Another cousin has learning difficulties and fits, but is heterozygous for AGU, and possibly has another uncharacterised autosomal recessive disorder. In a family with consanguinity when the clinical picture in an individual is not fully explained by the presence of one rare metabolic disease, it is essential to investigate further for the presence of others.

Physicochemical consequences of the perdeuteriation of glutathione S-transferase from S. japonicum

Glutathione S:-transferase (GST) from Schistosoma japonicum has been prepared in both normal protiated (pGST) and fully deuteriated (dGST) form by recombinant DNA technology. Electrospray mass spectrometry showed that the level of deuteriation in dGST was 96% and was homogeneous across the sample. This result is attributed to the use of a deuterium-tolerant host Escherichia coli strain in the preparation of the protein. 10 heteroatom-bound deuteriums (in addition to the carbon-bound deuteriums) were resistant to exchange when dGST was incubated in protiated buffer. The physicochemical and biological properties of the two proteins were compared. dGST was relatively less stable to heat denaturation and to proteolytic cleavage than was pGST. The midpoint transition temperature for pGST was 54.9 degrees C, whereas that for dGST was 51.0 degrees C. Static light-scattering measurements revealed that the association behavior of dGST is also different from that of pGST. The perdeuteriated enzyme shows a tendency to associate into dimers of the fundamental dimer. This is in contrast with results that have been obtained for other perdeuteriated proteins in which perdeuteriation has been shown to promote dissociation of aggregates. dGST showed a similar K(m) to pGST; similar results had been obtained previously with bacterial alkaline phosphatase. However, whereas the alkaline phosphatase showed a reduced rate of catalysis on deuteriation, dGST exhibited a slightly higher rate of catalysis than pGST. It is clear that the bulk substitution of deuterium for protium has significant effects on the properties of proteins. Until many more examples have been studied, it will be difficult to predict these effects for any given protein. Nevertheless, deuteriation represents an intriguing method of preparing functional analogs of recombinant proteins.

Complete mitochondrial genome sequences of two extinct moas clarify ratite evolution

The origin of the ratites, large flightless birds from the Southern Hemisphere, along with their flighted sister taxa, the South American tinamous, is central to understanding the role of plate tectonics in the distributions of modern birds and mammals. Defining the dates of ratite divergences is also critical for determining the age of modern avian orders. To resolve the ratite phylogeny and provide biogeographical data to examine these issues, we have here determined the first complete mitochondrial genome sequences of any extinct taxa--two New Zealand moa genera--along with a 1,000-base-pair sequence from an extinct Madagascan elephant-bird. For comparative data, we also generated 12 kilobases of contiguous sequence from the kiwi, cassowary, emu and two tinamou genera. This large dataset allows statistically precise estimates of molecular divergence dates and these support a Late Cretaceous vicariant speciation of ratite taxa, followed by the subsequent dispersal of the kiwi to New Zealand. This first molecular view of the break-up of Gondwana provides a new temporal framework for speciation events within other Gondwanan biota and can be used to evaluate competing biogeographical hypotheses.

Thermodynamics of ion-induced RNA folding in the hammerhead ribozyme: an isothermal titration calorimetric study

The hammerhead ribozyme undergoes a well-defined two-stage conformational folding process, induced by the binding of magnesium ions. In this study, we have used isothermal titration calorimetry to analyze the thermodynamics of magnesium binding and magnesium ion-induced folding of the ribozyme. Binding to the natural sequence ribozyme is strongly exothermic and can be analyzed in terms of sequential interaction at two sites with association constants K(A) = 480 and 2840 M(-1). Sequence variants of the hammerhead RNA give very different isothermal titration curves. An A14G variant that cannot undergo ion-induced folding exhibits endothermic binding. By contrast, a deoxyribose G5 variant that can undergo only the first of the two folding transitions gives a complex titration curve. However, despite these differences the ITC data for all three species can be analyzed in terms of the sequential binding of magnesium ions at two sites. While the binding affinities are all in the region of 10(3) M(-1), corresponding to free energies of Delta G degrees = -3.5 to -4 kcal mol(-1), the enthalpic and entropic contributions show much greater variation. The ITC experiments are in good agreement with earlier conformational studies of the folding of the ion-induced folding of the hammerhead ribozyme.

Prehospital endotracheal intubation for severe head injury in children: a reappraisal

Controversy exists regarding the efficacy of prehospital assisted ventilation by endotracheal intubation (ETI) versus bag-valve-mask (BVM) in serious pediatric head injury. The National Pediatric Trauma Registry (NPTR-3) data set was analyzed to examine this question. NPTR-3 (n = 31,464) was queried regarding the demographics, injury mechanism, injury severity, prehospital interventions, transport mode, mortality rate, injury complications, procedure and equipment failure or complications, and functional outcome of seriously head-injured patients (n = 578) with comparable injury mechanisms and injury severity who received endotracheal intubation (ETI) (n = 479; 83%) versus those who received BVM (n = 99; 17%). Mortality rate was virtually identical between the 2 groups (ETI = 48%, BVM = 48%), although children receiving ETI were significantly older (P < .01), more often transported by helicopter (P < .01), and more often received intravenous fluid in the field (P < .05). However, injury complications affecting nearly every body system or organ (except kidney, gut, and skin) occurred less often in children receiving ETI (ETI = 58%, BVM = 71%, P < .05). Procedure and equipment failure or complications, and functional outcome, were similar between the 2 groups. Prehospital endotracheal intubation appears to offer no demonstrable survival or functional advantage when compared with prehospital bag-valve-mask for prehospital assisted ventilation in serious pediatric head injury. Injury complications appear to occur somewhat less often among patients intubated in the field.

The TolA-recognition site of colicin N. ITC, SPR and stopped-flow fluorescence define a crucial 27-residue segment

Colicins translocate across the Escherichia coli outer membrane and periplasm by interacting with several receptors. After first binding to the outer membrane surface receptors via their central region, they interact with TolA or TonB proteins via their N-terminal region. Colicin N residues critical to TolA binding have been discovered, but the full extent of any colicin TolA site is unknown. We present, for the first time, a fully mapped TolA binding site for a colicin. It was determined through the use of alanine-scanning mutants, glutathione S-transferase fusion peptides and Biacore/fluorescence binding studies. The minimal TolA binding region is 27 residues and of similar size to the TolA binding region of bacteriophage g3p-D1 protein. Stopped-flow kinetic studies show that the binding to TolA follows slow association kinetics. The role of other E. coli Tol proteins in colicin translocation was also investigated. Isothermal titration microcalorimetry (ITC) and in vivo studies conclusively show that colicin N translocation does not require the presence of TolB. ITC also demonstrated colicin A interaction with TolB, and that colicin A in its native state does not interact with TolAII-III. Colicin N does not bind TolR-II. The TolA protein is shown to be unsuitable for direct immobilisation in Biacore analysis.

The 2000 Moyer Award. The relevance of base deficits after burn injuries

The relevance of an elevated base deficit (BD) during the fluid resuscitation of a thermally injured patient is not completely understood. After nonthermal trauma, early elevation of the BD represents insufficient cellular perfusion and is ultimately associated with a higher incidence of organ dysfunction and death. However, this relationship has not been completely examined after burn injuries. The purpose of this study was to determine if elevation of the BD during burn resuscitation was associated with potential consequences of malperfusion, such as systemic inflammatory response syndrome, acute respiratory distress syndrome, and multiple organ dysfunction. The records of 72 patients with burn injuries (mean age, 46 +/- 17 years; mean total body surface area burned, 44% +/- 18%) who required fluid resuscitation on admission to an adult regional burn center were analyzed. Patients with a mean BD of less than -6 mmol/L during the first 24 hours were compared with patients with a mean BD of more than -6 mmol/L. Despite adequate resuscitation with good maintenance of urinary output, the patients in the group with a mean BD of less than -6 mmol/L had more florid systemic inflammatory response syndrome (P = .004), had more prevalent acute respiratory distress syndrome (P = .012), and experienced more severe multiple organ dysfunction (P < .001) compared with patients in the group with a mean BD of more than -6 mmol/L. The results suggest that abnormal elevation of the BD after burn injuries represents a malperfusion state, which may not be recognized if only "traditional" parameters, such as UO, are followed. Furthermore, this state appears to be related to the onset of more severe systemic inflammation and organ dysfunction.

Bactericidal action of high-power Nd:YAG laser light on Escherichia coli in saline suspension

Infra-red light (1064 nm) from a high-power Nd:YAG laser caused more than 90% loss of viability of Escherichia coli during exposures that raised the temperature of PBS suspensions of the bacteria to 50 C in a thermocouple-equipped cuvette. In contrast, there was minimal loss of viability after heating the same suspensions to 50 degrees C in a water-bath, or in a PCR thermal cycler. The mechanism of laser killing at 50 degrees C was explored by differential scanning calorimetry, by laser treatment of transparent and turbid bacterial suspensions, and by optical absorbency studies of E. coli suspensions at 1064 nm. Taken together, the data suggested that the bactericidal action of Nd:YAG laser light at 50 degrees C was due partly to thermal heating and partly to an additional, as yet undefined, mechanism. Scanning electron microscopy revealed localized areas of surface damage on laser-exposed E. coli cells.

Fourteen novel mucopolysaccharidosis IVA producing mutations in GALNS gene

Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive disorder caused by a deficiency of the lysosomal N-acetylgalactosamine-6-sulfate sulfatase. Here, we report our analysis of data on 21 patients of diverse ethnic and geographic origins studied by SSCP and sequencing analysis. Sixteen mutations were detected, including 14 new mutations (11 missense, one premature termination, one splice site alteration, and one cryptic site alteration). The donor splice site mutation (IVS4 + 1G-->A) predicts that normal splicing will be abolished and that translation would lead to an immediate premature termination (W141X). Another novel nucleotide change outside the coding sequence is an intronic alteration (IVS9-42C-->T:ggtcggtgcggttggtgc) creating a potential cryptic donor site. The nucleotide sequence surrounding this alteration is highly suggestive of a consensus donor splice site. All 12 missense and nonsense mutations were shown by transient expression to abolish or greatly reduce GALNS activity, thereby providing an explanation as to why they produce MPS IVA. All mutations were readily confirmed by restriction enzyme or by allelic specific oligonucleotide analysis (ASO). These findings, coupled with previously reported mutations, bring the total of different mutations to 41 among independent families with MPS IVA, illustrating the extensive allelic heterogeneity among mutations producing MPS IVA.

Polymorphism of the transforming growth factor-beta 1 gene correlates with the development of coronary vasculopathy following cardiac transplantation

BACKGROUND

Expression of transforming growth factor-beta1 (TGF-beta1) is central to vascular repair due to its effects on smooth muscle cell, monocyte/macrophage, leucocyte, and extracellular matrix accumulation and proliferation. Genetic polymorphism at position +915 of the TGF-beta1 gene determines the degree of cytokine production in response to injury. We investigated this allelic variation on the development of cardiac transplant-related coronary vasculopathy (CV).

METHODS

Using sequence-specific primers to the TGF-beta1 gene region of interest, a polymerase chain reaction (PCR) and gel electrophoresis identified the genotype in 129 cardiac transplant recipients. An association was sought between the presence of a high- (GG) or low/intermediate-producing (CC/GC) genotype and the development of coronary vasculopathy diagnosed by coronary angiography.

RESULTS

C allele carriers made up 10.9% of the recipient population but were significantly less likely to develop coronary vasculopathy (p = 0. 0361). Mean time to diagnosis was 1240.5 days in G homozygotes relative to 2266.5 days in C allele carriers (p = 0.002). Pre- and 1-year posttransplant clinical variables were equivalent between the 2 groups. Multivariate analysis identified the GG genotype (p = 0. 042, hazard ratio 3.01, [95% CI, 1.056-10.99]), donor age (p = 0.002, hazard ratio 1.063, [95% CI, 1.029-1.097]), and number of acute-rejection episodes of grade 3 or greater in the first year (p = 0.029, hazard ratio 1.11, [95% CI, 1.05-1.26]) as significant predictors of vasculopathy.

CONCLUSION

This study demonstrates a correlation between a high-producing TGF-beta1 genotype and an earlier onset of cardiac-transplant coronary vasculopathy. This gives an important insight into the pathophysiology of cardiac transplant vasculopathy and suggests new treatment options.

Heat capacity of hydrogen-bonded networks: an alternative view of protein folding thermodynamics

Large changes in heat capacity (deltaCp) have long been regarded as the characteristic thermodynamic signature of hydrophobic interactions. However, similar effects arise quite generally in order-disorder transitions in homogeneous systems, particularly those comprising hydrogen-bonded networks, and this may have significance for our understanding of protein folding and other biomolecular processes. The positive deltaCp associated with unfolding of globular proteins in water, thought to be due to hydrophobic interactions, is also typical of the values found for the melting of crystalline solids, where the effect is greatest for the melting of polar compounds, including pure water. This suggests an alternative model of protein folding based on the thermodynamics of phase transitions in hydrogen-bonded networks. Folded proteins may be viewed as islands of cooperatively-ordered hydrogen-bonded structure, floating in an aqueous network of less-well-ordered H-bonds in which the degree of hydrogen bonding decreases with increasing temperature. The enthalpy of melting of the protein consequently increases with temperature. A simple algebraic model, based on the overall number of protein and solvent hydrogen bonds in folded and unfolded states, shows how deltaCp from this source could match the hydrophobic contribution. This confirms the growing view that the thermodynamics of protein folding, and other interactions in aqueous systems, are best described in terms of a mixture of polar and non-polar effects in which no one contribution is necessarily dominant.

Making a difference to practice: clinical benchmarking. Part 2

In the second of two articles, the authors explore further the use of clinical practice benchmarking. In particular, practice related to improving nutritional care for patients, caring for patients with mental health needs and safely transferring critically ill patients is examined. The authors conclude by summarising the value of clinical practice benchmarking and how it made a difference to practice in their trust. The first article appeared in Nursing Standard last week.

Cloning and characterization of the murine coagulation factor X gene

The gene encoding murine coagulation factor X (fX) was isolated and characterized from a lamdaFIX II library generated from murine genomic DNA. The 20130 bp sequence contains 18049 nucleotides that extend from the initiating methionine to the polyadenylation site. 1056 nucleotides 5' of the start codon were determined and contain putative start sites for the FX mRNA as well as sites for binding of putative transcription factors. The sequence extends 1024 3' of the polyadenylation site. The gene contains 8 exons and 7 introns which were determined by comparing the mouse FX cDNA and gene sequences. The exonic structure of the gene is similar to that of the other mammalian vitamin K-dependent serine proteases of the coagulation system. These include an exon encoding the prepropepetide, the gla-domain, a short helical stack, two exons for the two EGF domains, the activation pepetide, and two exons encoding the serine protease domain. The 5' sequence of the mouse FX gene overlaps with the 3' region of the FVII gene indicating that the murine FVII and FX gene are arranged in a head to tail arrangement as they are in humans.

Are women discriminated against for lipid lowering therapy? Results from a prospective cohort of women with coronary artery disease

The objective of the study was to compare the lipid management of men and women with documented coronary artery disease in 587 patients (433 men and 154 women) undergoing coronary angiography between 1991 and 1995. A fasting total cholesterol (TC) was measured in all patients on the morning of angiography. A postal/telephone follow-up was carried out one year after angiography in a subpopulation of 278 patients (194 men and 84 women) who were not taking lipid-lowering therapy (LLT) or whose TC was > 5.2 mmol/l at the time of angiography. At baseline, mean TC was 5.89 mmol/l (SE 0.06) in the men and 6.47 mmol/l (SE 0.09) in the women (p = < 0.0001). Action or recommendation to institute LLT was taken in 141 (32.7%) men and 62 (40.3%) women (p = 0.09). In the follow-up population, comparing men with women, 74 (38.3%) vs 39 (46.4%) were taking LLT (p = 0.21); 56 (28.9%) vs 26 (31.0%) had not undergone repeat TC testing (p = 0.73); when performed, repeat TC was 5.75 (0.09) mmol/l vs 5.64 (0.16) mmol/l (p = 0.53); mean decrease in TC between baseline and follow-up was 0.86 (0.10) mmol/l vs 1.01 (0.21) mmol/l (p = 0.51). There was no significant gender difference in lipid management either at the time of coronary angiography or subsequent follow-up, although the level of lipid-lowering drug use remained inadequate in both sexes.

Making a difference to practice: clinical benchmarking. Part 1

In the first of two articles, the authors describe how an internal clinical practice benchmarking group was established in Preston to compare and share examples of best practice. The aim was to ensure consistent high standards of care practice across the trust. Activity related to discharge planning and visiting is used here to illustrate the effectiveness of clinical practice benchmarking as a continuous quality improvement tool. The second article will appear in Nursing Standard on May 3.

Chest pain in the emergency department

The assessment of patients with chest pain is challenging for any emergency physician because of the spectrum of illness covered by this symptom. Patients may have a serious life-threatening condition or a trivial self-limiting illness. This article presents an approach to the assessment and early management of patients presenting with acute non-traumatic chest pain in the emergency department.

Population genetics of ice age brown bears

The Pleistocene was a dynamic period for Holarctic mammal species, complicated by episodes of glaciation, local extinctions, and intercontinental migration. The genetic consequences of these events are difficult to resolve from the study of present-day populations. To provide a direct view of population genetics in the late Pleistocene, we measured mitochondrial DNA sequence variation in seven permafrost-preserved brown bear (Ursus arctos) specimens, dated from 14,000 to 42,000 years ago. Approximately 36,000 years ago, the Beringian brown bear population had a higher genetic diversity than any extant North American population, but by 15,000 years ago genetic diversity appears similar to the modern day. The older, genetically diverse, Beringian population contained sequences from three clades now restricted to local regions within North America, indicating that current phylogeographic patterns may provide misleading data for evolutionary studies and conservation management. The late Pleistocene phylogeographic data also indicate possible colonization routes to areas south of the Cordilleran ice sheet.

The ABA-1 allergen of Ascaris lumbricoides: sequence polymorphism, stage and tissue-specific expression, lipid binding function, and protein biophysical properties

The ABA-1 protein of Ascaris lumbricoides (of humans) and Ascaris suum (of pigs) is abundant in the pseudocoelomic fluid of the parasites and also appears to be released by the tissue-parasitic larvae and the adult stages. The genes encoding the polyprotein precursor of ABA-1 (aba-1) were found to be arranged similarly in the two taxa, comprising tandemly repeating units encoding a large polyprotein which is cleaved to yield polypeptides of approximately 15 kDa which fall into 2 distinct classes, types A and B. The polyprotein possibly comprises only 10 units. The aba-1 gene of A. lumbricoides is polymorphic, and the majority of substitutions observed occur in or near predicted loop regions in the encoded proteins. mRNA for ABA-1 is present in infective larvae within the egg, and in all parasitic stages, but was not detectable in unembryonated eggs. ABA-1 mRNA was confined to the gut of adult parasites, and not in body wall or reproductive tissues. Recombinant protein representing a single A-type unit for the A. lumbricoides aba-1 gene was produced and found to bind retinol (Vitamin A) and a range of fatty acids, including the pharmacologically active lipids lysophosphatidic acid, lysoplatelet activating factor, and there was also evidence of binding to leukotrienes. It failed to bind to any of the anthelmintics screened. Differential Scanning Calorimetry showed that the recombinant protein was highly stable, and unfolded in a single transition at 90.4 degrees C. Analysis of the transition indicated that the protein occurs as a dimer and that the dimer dissociates simultaneously with the unfolding of the monomer units.

Predicting inpatient mortality for pediatric trauma patients with blunt injuries: a better alternative

PURPOSE

The aim of this study was to identify significant independent predictors of inpatient mortality rates for pediatric victims of blunt trauma and to develop a formula for predicting the probability of inpatient mortality for these patients.

METHODS

Emergency department and inpatient data from 2,923 pediatric victims of blunt injury in the New York State Trauma Registry in 1994 and 1995 were used to explore the relationship between patient risk factors and mortality rate. A stepwise logistic regression model with P<.05 was developed using survival status asthe dependent variable. Independent variables included are elements of the Pediatric Trauma Score (PTS), additional elements from the Revised Trauma Score (RTS), the motor response and eye opening components of the Glasgow Coma Scale (GCS), age-specific systolic blood pressure, the AVPU score, and 2 measures of anatomic injury severity (the Injury Severity Score [ISS] and the International Classification of Disease, Ninth Revision-based Injury Severity Score [ICISS]).

RESULTS

The only significant independent predictors of severity that emerged were the ICISS, no motor response (best motor response = 1) from the GCS, and the unresponsive component from the AVPU score. The statistical model exhibited an excellent fit (C statistic = .964). The specificity associated with the prediction of inpatient mortality rate based on the presence of 1 or more of these risk factors was .926, and the sensitivity was .944.

CONCLUSION

The best independent predictors of inpatient mortality rate for pediatric trauma patients with blunt injuries include variables not specifically contained in the PTS or the RTS: ICISS, no motor response (best motor response = 1) from the GCS, and the unresponsive component of the AVPU score.

A randomised placebo controlled trial of the effects of tibolone on blood pressure and lipids in hypertensive women

The effects of hormone replacement therapy in hypertensive women are controversial. This randomised placebo controlled trial assessed the effect of tibolone 2.5 mg on blood pressure and fasting plasma lipids in 29 hypertensive postmenopausal women over 6 months using a 2:1 randomisation to tibolone. The primary clinical end-point was mean office blood pressure. At 6 months systolic blood pressure declined by 5.30 +/- 2.87% vs 4.94 +/- 3.37% whilst diastolic blood pressure declined 5.38 +/- 2.65% vs 0.85 +/- 3.69% on tibolone and placebo respectively. These differences were not statistically significant. Triglycerides decreased by 33.3 +/- 6.1% vs 7.6 +/- 7.9% (P < 0.01) and high-density lipoprotein (HDL)-cholesterol by 21.7 +/- 3.8% vs 2.4 +/- 2.6% (P < 0.01) with tibolone as opposed to placebo. No significant differences were observed in total cholesterol, low-density lipoprotein (LDL)-cholesterol and lipoprotein (a). Fibrinogen levels were reduced by 13.6 +/- 6.8% on tibolone compared to a 19.3 +/- 15.4% rise (P < 0.05) on placebo. This study suggests that tibolone has no deleterious effect on blood pressure in women with hypertension but has contrasting effects on biochemical risk factors. Large-scale studies are required to determine the overall effect of tibolone on cardiovascular morbidity and mortality.

Effect of 1-(gamma)linolenyl-3-eicosapentaenoyl propane diol on the growth of human pancreatic carcinoma in vitro and in vivo

Essential fatty acids such as (gamma)linolenic (GLA) and eicosapentaenoic (EPA) acids have been proposed as anticancer drugs. The aim of this study was to test the effect of a lipid emulsion containing both GLA and EPA in a novel chemical formulation of 1-(gamma)linolenyl-3-eicosapentaenoyl propane diol on the growth of human pancreatic carcinoma in vitro and in nude mice. This compound had a dose-dependent growth-inhibitory effect on human pancreatic cancer cell lines MIA PaCa-2 and Panc-1 in vitro. The concentration necessary for 50% growth inhibition was 25 micromol/l for MIA PaCa-2 and 68 micromol/l for Panc-1 (95% CI 20-29 and 59-77 micromol/l respectively). Nude mice bearing subcutaneous pancreatic tumours produced with the MIA PaCa-2 cell line were treated with the maximum tolerated dose (6.75 mg GLA and 7.3 mg EPA per g of body weight) administered over 10 days by daily intravenous (i.v.) bolus injections. No antitumour effect or major alteration in tumour lipid fatty acid composition was seen in comparison with control animals. Concurrent treatment with parenteral iron (iron saccharate, 5 microg/gram body weight daily) did not make a significant difference. Further improvements in fatty acid delivery mechanisms are necessary before they can become useful anticancer agents.

National benchmarking as a support system for clinical governance

Audit of the management of acute asthma in hospital has developed in tandem with guidelines produced and updated by the British Thoracic Society (BTS), on the principle that agreed guidelines combined with systematic review of practice by periodic audit are more likely to result in improvements in practice than guidelines alone. A short audit data set was distilled from previous experience with more elaborate tools and made available nationally to audit departments and through letters to consultant members of the BTS. Hospitals have been able to contribute since 1990. The data set reflects key items of the process of care: peak flow measured on admission and twice daily during the hospital stay; blood gases on admission; systemic corticosteroids as an inpatient; discharged with inhaled and oral corticosteroids; written self-management plans; follow-up arrangements. Data from 4,741 admissions over a seven year period are presented. The proportion of patients nationally receiving these items of asthma care is given. The median values for hospital performance improved significantly over the seven years, although there is potential for further improvement. If these data represent the national picture, they could form the basis upon which to set national standards for the care of patients with acute asthma in hospital. A further result of the developing audit has been the recognition of the value of external benchmarking in providing a context for the interpretation of local audit results. This audit system provides hospitals with a quick and easy method of obtaining an overview of local performance, with comparative national data for the same year. This has potential as a tool for clinical governance with much wider applicability, providing the data are handled carefully, particularly as the variability between hospitals diminishes over time.

An examination of the volume-mortality relationship for New York State trauma centers

OBJECTIVES

New York State Trauma Registry data were analyzed to determine whether there is a significant relationship between the volume of trauma patients treated by a trauma center and its risk-adjusted inpatient mortality rate.

METHODS

Stepwise logistic regression was used to identify significant independent predictors of mortality, their weights, and the probability of in-hospital mortality for each patient. These data were then used to calculate risk-adjusted mortality rates for various ranges of hospital volume. Ranges were identified on the basis of homogeneity of mortality rates, the number of hospitals in each range, and the number of patients in each range. Three volume measures were used: (1) total annual volume of trauma cases > or = 1200 and total annual volume > or = 240 for patients with Injury Severity Score (ISS) > or = 15 (equivalent to American College of Surgeons [ACS] criteria), (2) total annual volume of patients with ISS > or = 15, and (3) total annual volume of cases in the Registry (approximately, inpatients with ISS > or = 9).

RESULTS

Results show that the 35 New York State trauma centers not meeting the ACS criteria had lower, but not significantly lower, observed and risk-adjusted mortality rates (7.62% and 8.25%, respectively) than the corresponding rates for the 8 New York State trauma centers that met the ACS criteria (9.36% and 8.83%, respectively). Regarding the other two criteria, hospital ranges representing lower annual volumes tended to have somewhat lower, although not significantly lower, observed and risk-adjusted mortality rates. For example, using a total annual volume for patients with ISS > or = 15, the risk-adjusted mortality rates for the volume ranges 1-150, 151-250, and 251+ were 7.78%, 9.23%, and 8.70%, respectively.

CONCLUSIONS

We were unable to document an inverse relationship between hospital volume and inpatient mortality rate for trauma centers in New York State. Volume criteria should not be considered indicators of the quality of trauma care.

Accounting for intubation status in predicting mortality for victims of motor vehicle crashes

BACKGROUND

Two of the important predictors of mortality for trauma patients are the Glasgow Coma Scale and the respiratory rate. However, for intubated patients, the verbal response component of the Glasgow Coma Scale and the respiratory rate cannot be accurately obtained. This study extends previous work that attempts to predict mortality accurately for intubated patients without using verbal response and respiratory rate.

METHODS

The New York State Trauma Registry was used to identify 1994 and 1995 victims of motor vehicle crashes (MVCs). For the subset of patients who were not intubated, we developed two statistical models to predict mortality: one did not contain verbal response or respiratory rate, and the other contained a predicted verbal response. These were compared with a model that did include verbal response and respiratory rate. We also compared the predictive abilities of the first two models for all MVC patients (intubated and nonintubated) and determined the extent to which intubated patients were at increased risk of dying in the hospital after having adjusted for other predictors of mortality.

RESULTS

For nonintubated patients, the statistical model without verbal response and the model with predicted verbal response had slightly better discrimination and worse calibration than the model that included verbal response and respiratory rate. Predicted verbal response did not improve the strength of the model without verbal response. For all MVC patients (intubated and nonintubated), predicted verbal response was not a significant predictor of mortality when used in combination with the other predictors. Intubation status was a significant predictor, with intubated patients having a higher probability of dying in the hospital than patients with otherwise identical risk factors.

CONCLUSION

Inpatient mortality for intubated MVC patients can be accurately predicted without respiratory rate or verbal response. There appears to be no need for predicted verbal response to be part of the prediction formula, but intubation status is an important independent predictor of mortality and should be used in statistical models that predict mortality for MVC patients.

Quantitation of metal ion and DNA junction binding to the Holliday junction endonuclease Cce1

Cce1 is a magnesium-dependent Holliday junction endonuclease involved in the resolution of recombining mitochondrial DNA in Saccharomyces cerevisiae. Cce1 binds four-way DNA junctions as a dimer, opening the junction into an extended, 4-fold symmetric structure, and resolves junctions by the introduction of paired nicks in opposing strands at the point of strand exchange. In the present study, we have examined the interactions of wild-type Cce1 with a noncleavable four-way DNA junction and metal ions (Mg(2+) and Mn(2+)) using isothermal titration calorimetry, EPR, and gel electrophoresis techniques. Mg(2+) or Mn(2+) ions bind to Cce1 in the absence of DNA junctions with a stoichiometry of two metal ions per Cce1 monomer. Cce1 binds to four-way junctions with a stoichiometry of two Cce1 dimers per junction molecule in the presence of EDTA, and one dimer of Cce1 per junction in 15 mM magnesium. The presence of 15 mM Mg(2+) dramatically reduces the affinity of Cce1 for four-way DNA junctions, by about 900-fold. This allows an estimation of DeltaG degrees for stacking of four-way DNA junction 7 of -4.1 kcal/mol, consistent with the estimate of -3.3 to -4.5 kcal/mol calculated from branch migration and NMR experiments [Overmars and Altona (1997) J. Mol. Biol. 273, 519-524; Panyutin et al. (1995) EMBO J. 14, 1819-1826]. The striking effect of magnesium ions on the affinity of Cce1 binding to the four-way junction is predicted to be a general one for proteins that unfold the stacked X-structure of the Holliday junction on binding.

I.V. fluid therapy. Part 2. I.V. fluid selection

I.v. fluid selection depends on the estimated fluid loss, the primary fluid compartment involved, the patient's underlying problem and the physiological and haemodynamic impact of the i.v. solution. Clinically, the most important problem is intravascular fluid volume deficit, which is associated with hypotension, inadequate tissue oxygenation and hypoperfusion of essential organs. Intravascular volume resuscitation is therefore of primary importance. Crystalloid solutions have the disadvantage of only small amounts remaining in the IVS whereas colloids are known as plasma volume expanders due to predominantly remaining in the IVS in the presence of an intact capillary endothelium. Managing i.v. fluid administration requires close observation of the patient's subtle responses that may indicate states of fluid depletion or overload. Understanding the physiological principles of the body's fluid distribution in relation to the clinical assessment of the patient's hydration status, together with knowledge of the selected i.v. solution's properties, will enable the nurse to provide quality nursing care and improve patient outcomes.

Relationships of the extinct moa-nalos, flightless Hawaiian waterfowl, based on ancient DNA

The extinct moa-nalos were very large, flightless waterfowl from the Hawaiian islands. We extracted, amplified and sequenced mitochondrial DNA from fossil moa-nalo bones to determine their systematic relationships and lend insight into their biogeographical history. The closest living relatives of these massive, goose-like birds are the familiar dabbling ducks (tribe Anatini). Moa-nalos, however, are not closely related to any one extant species, but represent an ancient lineage that colonized the Hawaiian islands and evolved flightlessness long before the emergence of the youngest island, Hawaii, from which they are absent. Ancient DNA yields a novel hypothesis for the relationships of these bizarre birds, whereas the evidence of phylogeny in morphological characters was obscured by the evolutionary transformation of a small, volant duck into a giant, terrestrial herbivore.

The caseload, assessment and treatment of atopic dermatitis: a survey of Australian dermatologists

In early 1995 we surveyed all 250 practicing Australian members of the Australasian College of Dermatologists by a mail-out questionnaire to determine information, such as the caseload imposed by atopic dermatitis, the severity of cases seen by dermatologists, current treatment and dermatologists' satisfaction with treatment. One hundred and forty-nine responses were received. Fifty per cent of patients with atopic dermatitis seen by dermatologists were younger than 10 years, 18% were 10-16 years, and 52% were older than 16 years. Disease was considered to be severe in 18% of patients, moderate in 41% and mild in 41%. Emollients and topical corticosteroids were the most commonly used treatments but there was wide variation in other treatments used by individual dermatologists. Only 10% of respondents were very satisfied with existing treatments for severe atopic dermatitis; 20% of patients with severe disease were considered as refractory or non-responsive. New therapies such as cyclosporin have the potential to improve existing standards of care.

NOS2-derived nitric oxide regulates the size, quantity and quality of granuloma formation in Mycobacterium avium-infected mice without affecting bacterial loads

Granuloma formation in response to mycobacterial infections is associated with increased expression of inducible nitric oxide synthase (NOS2) within granuloma macrophages and increased levels of nitrate/nitrite in the sera of infected mice. Continuous treatment with 5 mm or 10 mm l-N6-(1-imino-ethyl)-lysine (L-NIL), a selective NOS2-inhibitor, in acidified drinking water for up to 7 weeks consistently reduced infection-induced nitrate/nitrite to background levels in mycobacteria-infected BALB/c mice. Oral treatment with 5 mm L-NIL initiated at the time of infection significantly exacerbated growth of Mycobacterium tuberculosis, but had no effect on Mycobacterium avium colony-forming unit development in the liver, spleen and lungs of intravenously infected mice. In order to examine the role of nitric oxide in mycobacteria-induced granulomatous inflammation in the absence of any effect on the bacterial load, M. avium-infected mice were treated with 5 mm L-NIL from day 1 through 38 and the development of granulomatous lesions in the liver was assessed by histology, immunohistology and reverse-transcription-polymerase chain reaction (RT-PCR). Computer- and video-assisted morphometry performed at 4 and 7 weeks post-infection showed that treatment with L-NIL led to markedly increased number, cellularity and size of granulomatous lesions in infected mice regardless of the virulence of the M. avium isolate used for infection. Immunohistology of the liver revealed that in mice treated with L-NIL, the numbers of CD3+ T cells, CD21/35+ B cells, CD11b+ macrophages and RB6-8C5+ granulocytes associated with granulomatous lesions was increased. RT-PCR of the liver showed that in L-NIL-treated mice infected with M. avium, mRNA levels of tumour necrosis factor, interleukin-12p40, interferon-gamma, interleukin-10 and interferon-gamma-inducible protein-10 (IP-10) were up-regulated, while mRNA levels of interleukin-4, monocyte chemotactic protein-1 (MCP-1) and MCP-5 were similar to those in untreated control infected mice. When M. avium-infected mice were treated with 5 mm L-NIL between the 5th and 12th weeks of infection, similar changes in granuloma number and size were found in the absence of any effect on the bacterial load. These findings demonstrate that nitric oxide regulates the number, size and cellular composition of M. avium-induced granulomas independently of antibacterial effects by modulating the cytokine profile within infected tissues.

Hepatitis from 5-methoxypsoralen occurring in a patient with previous flucloxacillin hepatitis

A 55-year-old woman with psoriasis vulgaris was treated with oral 5-methoxypsoralen and UVA photochemotherapy. After 40 treatments over 3 months she became unwell with hepatitis attributable to the psoralen. Six years earlier she developed cholestatic hepatitis to flucloxacillin. A previous history of drug-induced reactions should be sought before prescribing further drugs with similar adverse effects.

Thermodynamic analysis of biomolecular interactions

Direct measurement of the thermodynamics of biomolecular interactions is now relatively easy. Interpretation of these thermodynamics in simple molecular terms is not. Recent work shows how the multiplicity of weak noncovalent interactions, and the inevitable enthalpy/entropy compensation that these interactions engender, lead to difficulties in teasing out the different components.

Homing in on the role of transition metals in the HNH motif of colicin endonucleases

The cytotoxic domain of the bacteriocin colicin E9 (the E9 DNase) is a nonspecific endonuclease that must traverse two membranes to reach its cellular target, bacterial DNA. Recent structural studies revealed that the active site of colicin DNases encompasses the HNH motif found in homing endonucleases, and bound within this motif a single transition metal ion (either Zn(2+) or Ni(2+)) the role of which is unknown. In the present work we find that neither Zn(2+) nor Ni(2+) is required for DNase activity, which instead requires Mg(2+) ions, but binding transition metals to the E9 DNase causes subtle changes to both secondary and tertiary structure. Spectroscopic, proteolytic, and calorimetric data show that, accompanying the binding of 1 eq of Zn(2+), Ni(2+), or Co(2+), the thermodynamic stability of the domain increased substantially, and that the equilibrium dissociation constant for Zn(2+) was less than or equal to nanomolar, while that for Co(2+) and Ni (2+) was micromolar. Our data demonstrate that the transition metal is not essential for colicin DNase activity but rather serves a structural role. We speculate that the HNH motif has been adapted for use by endonuclease colicins because of its involvement in DNA recognition and because removal of the bound metal ion destabilizes the DNase domain, a likely prerequisite for its translocation across bacterial membranes.

Formation and biochemical characterization of tube/pelle death domain complexes: critical regulators of postreceptor signaling by the Drosophila toll receptor

In Drosophila, the Toll receptor signaling pathway is required for embryonic dorso-ventral patterning and at later developmental stages for innate immune responses. It is thought that dimerization of the receptor by binding of the ligand spätzle causes the formation of a postreceptor activation complex at the cytoplasmic surface of the membrane. Two components of this complex are the adaptor tube and protein kinase pelle. These proteins both have "death domains", protein interaction motifs found in a number of signaling pathways, particularly those involved in apoptotic cell death. It is thought that pelle is bound by tube during formation of the activation complexes, and that this interaction is mediated by the death domains. In this paper, we show using the yeast two-hybrid system that the wild-type tube and pelle death domains bind together. Mutant tube proteins which do not support signaling in the embryo are also unable to bind pelle in the 2-hybrid assay. We have purified proteins corresponding to the death domains of tube and pelle and show that these form corresponding heterodimeric complexes in vitro. Partial proteolysis reveals a smaller core consisting of the minimal death domain sequences. We have studied the tube/pelle interaction with the techniques of surface plasmon resonance, analytical ultracentrifugation and isothermal titration calorimetry. These measurements produce a value of K(d) for the complex of about 0.5 microM.

A randomised comparison of the effects of oral versus transdermal 17beta-oestradiol, each combined with sequential oral norethisterone acetate, on serum lipoprotein levels

OBJECTIVE

To investigate the effects of oral versus transdermal 17beta-oestradiol, given in both cases with sequential addition of oral norethisterone acetate, on serum lipid and lipoprotein levels in postmenopausal women.

DESIGN

Open, randomised, parallel groups study.

SETTING

University Clinical Research Group.

POPULATION

Sixty-four postmenopausal women with climacteric complaints who were otherwise healthy were screened. Of these, 58 fulfilled the entry criteria.

METHODS

Fifty-eight postmenopausal women were randomised to receive either oral 17beta-oestradiol/oestriol (Trisequens) or transdermal 17beta-oestradiol (Estrapak) together with cyclical addition of norethisterone acetate for 48 weeks.

MAIN OUTCOME MEASURES

Serum levels of total cholesterol, triglycerides, high density lipoproteins (HDL), low density lipoproteins (LDL), very low density lipoproteins (VLDL), apolipoproteins, and lipoprotein(a) at baseline, and after 46 weeks (oestrogen-alone phase), and 48 weeks (oestrogen-progestogen phase) of treatment.

RESULTS

Oral oestradiol therapy did not affect serum total cholesterol levels during the oestrogen-alone phase, but during the combined phase there was a 5% fall (P < 0.05) due to a 7% decrease in LDL cholesterol levels (P < 0.01). Oral therapy also increased serum triglyceride levels by 9.4% during the oestrogen-alone phase (P < 0.05). During the combined phase of transdermal therapy, there was a 19% fall in serum triglyceride levels (P < 0.05) and a 6% fall in HDL levels (P < 0.05). Oral oestradiol reduced lipoprotein(a) levels by 31% during the oestrogen-alone phase and by 37% with norethisterone acetate addition (P < 0.05). Transdermal therapy had no significant effect on lipoprotein(a).

CONCLUSIONS

Other than a minor fall in HDL3 in women receiving transdermal 17beta-oestradiol, coadministration of oral progestogen in general improved, rather than worsened, this serum lipoprotein profile.

Permeability characteristics of human oocytes in the presence of the cryoprotectant dimethylsulphoxide

Equilibration of oocytes with cryoprotectants is a prerequisite of low temperature storage. However, cryoprotectant exposure may induce damage via osmotic stress. Knowledge of cell membrane permeability characteristics and their temperature dependence would facilitate the design of cryopreservation protocols in which osmotic stress is minimized and the incidence of intracellular freezing is reduced. To obtain such data, the volume change of donated human oocytes following exposure to cryoprotectant was measured at a variety of temperatures. After removal of cumulus cells, each oocyte was placed in a 5 microl droplet of phosphate-buffered medium. The oocyte was held in position by suction generated using a fine pipette and perfused with 1 ml 1.5 mol/l dimethylsulphoxide (DMSO) at 30, 24 or 10 degrees C. The volume of the oocyte before, during and after perfusion was recorded by videomicroscopy. Oocyte volume was calculated from radius measurements and the Kedem-Katchalsky (K-K) passive coupled transport coefficients, namely L(p) (hydraulic permeability), P(DMSO) (permeability to DMSO) and sigma (reflection coefficient) were derived. The resulting coefficients were L(p) = 1. 65 +/- 0.15, 0.70 +/- 0.06 and 0.28 +/- 0.04 microm/min.atm; P(DMSO) = 0.79 +/- 0.10, 0.25 +/- 0.04 and 0.06 +/- 0.01 microm/s and sigma = 0.97 +/- 0.01, 0.94 +/- 0.03 and 0.96 +/- 0.01 at 30, 24 and 10 degrees C respectively. The activation energy for L(p) was 14.70 and for P(DMSO) was 20.82 kcal/mol. The permeability parameters of human oocytes are higher than those of murine oocytes, suggesting that they require a shorter period of exposure to DMSO with concomitantly reduced toxic effects.

Why patients do not attend cardiac rehabilitation: role of intentions and illness beliefs

OBJECTIVE

Many patients fail to attend cardiac rehabilitation. Attempts to identify sociodemographic or clinical predictors of non-attendance have not been very successful; therfore, this study aimed to determine whether the illness beliefs held during hospitalisation by patients who had suffered acute myocardial infarction or who had undergone coronary artery bypass graft surgery could predict cardiac rehabilitation attendance.

SUBJECTS AND METHODS

152 patients were prospectively studied of whom 41% had attended cardiac rehabilitation at six months.

RESULTS

In addition to being older, less aware of their cholesterol values, and less likely to be employed, non-attenders were less likely to believe their condition was controllable and that their lifestyle may have contributed to their illness.

CONCLUSION

It should now be determined whether interventions aimed at optimising certain perceptions could promote cardiac rehabilitation uptake among those patients who could benefit the most.

A family IIb xylan-binding domain has a similar secondary structure to a homologous family IIa cellulose-binding domain but different ligand specificity

BACKGROUND

Many enzymes that digest polysaccharides contain separate polysaccharide-binding domains. Structures have been previously determined for a number of cellulose-binding domains (CBDs) from cellulases.

RESULTS

The family IIb xylan-binding domain 1 (XBD1) from Cellulomonas fimi xylanase D is shown to bind xylan but not cellulose. Its structure is similar to that of the homologous family IIa CBD from C. fimi Cex, consisting of two four-stranded beta sheets that form a twisted 'beta sandwich'. The xylan-binding site is a groove made from two tryptophan residues that stack against the faces of the sugar rings, plus several hydrogen-bonding polar residues.

CONCLUSIONS

The biggest difference between the family IIa and IIb domains is that in the former the solvent-exposed tryptophan sidechains are coplanar, whereas in the latter they are perpendicular, forming a twisted binding site. The binding sites are therefore complementary to the secondary structures of the ligands cellulose and xylan. XBD1 and CexCBD represent a striking example of two proteins that have high sequence similarity but a different function.

Predictors of mortality in adult patients with blunt injuries in New York State: a comparison of the Trauma and Injury Severity Score (TRISS) and the International Classification of Disease, Ninth Revision-based Injury Severity Score (ICISS)

BACKGROUND

The purpose of this study was to determine the statistical model that best predicted mortality from blunt trauma using a contemporary population-based database.

METHODS

1994-1995 New York State Trauma Registry data for patients with blunt injuries were used to predict mortality using three statistical models: (1) the original Trauma and Injury Severity Score (TRISS) model based on Major Trauma Outcome Study data, (2) a new TRISS model whose coefficients were derived using New York data, and (3) the International Classification of Disease, Ninth Revision-based Injury Severity Score (ICISS) with predicted survival values obtained from the Agency for Health Care Policy and Research's Health Care Utilization Project. The models were compared with respect to discrimination (using the C statistic) and calibration (using the Hosmer-Lemeshow [H-L] statistic). In addition, the models were tested to see how well they predicted outcomes for each of the three mechanisms of blunt injury.

RESULTS

The ICISS model had a significantly higher C statistic (0.878) and a better H-L statistic (29.38) for predicting mortality for all adult patients with blunt injuries. The original TRISS model had very poor calibration (H-L = 687.38). None of the three models predicted mortality accurately for victims of motor vehicle crashes or victims of low falls. When separate models were developed for all motor vehicle crashes, low falls, and other blunt injuries, the ICISS and New York TRISS models both fit well, although the calibration was marginal in most cases. The ICISS model had a statistically significantly higher C statistic for other blunt injuries and for motor vehicle crashes. The New York TRISS model had better calibration for low falls.

CONCLUSIONS

The ICISS has promise as an alternative to TRISS, but many more comparative studies need to be undertaken using updated TRISS coefficients. Models should also be developed for mechanisms of injury, not just for blunt and penetrating injuries.

Long-term follow-up following bone marrow transplantation for Hunter disease

Bone marrow transplantation (BMT) was performed in 10 patients with Hunter disease (mucopolysaccharidosis type II, iduronate-2-sulphatase deficiency). The donor was an HLA-identical sibling in 2 cases, an HLA-nonidentical relative in 6 cases, a volunteer unrelated donor in 1 case, and details were not available in 1 case. Only three patients have survived for more than 7 years post BMT; however, this high mortality probably resulted from poor donor selection. In two, there has been a steady progression of physical disability and mental handicap. One patient has maintained normal intellectual development, with only mild physical disability. It is possible that BMT may be useful in selected patients with MPS II.

Cryopreservation of bovine ovarian tissue: structural normality of follicles after thawing and culture in vitro

The recovery of viable follicles from cryopreserved ovarian tissue would be of benefit in many areas of assisted reproduction. Structural integrity needs to be maintained following cryopreservation of ovarian tissue in order to retrieve healthy follicles which can then be cultured in vitro to produce viable oocytes. We have assessed the effect of in vitro culture of bovine tissue for 0, 1, 4, 24, or 48 h after exposure to, or cryopreservation in, dimethylsulphoxide. Immediately after freezing, normality of primary and preantral follicles within the tissue was significantly lower than for tissue exposed to the cryoprotectant without freezing or for control tissue. After 4 h in culture, cryopreserved tissue appeared to have recovered from damage caused by freezing, although the percentage of tissue with normal morphology declined after 24 and 48 h of culture. There was no significant difference between percentage normality in control tissue and tissue exposed to the cryoprotectant without freezing for any of the culture times studied. These data indicate that it is possible to freeze/thaw bovine ovarian tissue while retaining a reasonable yield of morphologically intact follicles and that a short period of post-thaw culture may enhance follicle recovery.

Ligand binding by antibody IgE Lb4: assessment of binding site preferences using microcalorimetry, docking, and free energy simulations

Antibody IgE Lb4 interacts favorably with a large number of different compounds. To improve the current understanding of the structural basis of this vast cross-reactivity, the binding of three dinitrophenyl (DNP) amino acids (DNP-alanine, DNP-glycine, and DNP-serine) is investigated in detail by means of docking and molecular dynamics free energy simulations. Experimental binding energies obtained by isothermal titration microcalorimetry are used to judge the results of the computational studies. For all three ligands, the docking procedure proposes two plausible subsites within the binding region formed by the antibody CDR loops. By subsequent molecular dynamics simulations and calculations of relative free energies of binding, one of these subsites, a tyrosine-surrounded pocket, is revealed as the preferred point of complexation. For this subsite, results consistent with experimental observations are obtained; DNP-glycine is found to bind better than DNP-serine, and this, in turn, is found to bind better than DNP-alanine. The suggested binding mode makes it possible to explain both the moderate binding affinity and the differences in binding energy among the three ligands.

Independently melting modules and highly structured intermodular junctions within complement receptor type 1

A segment of complement receptor type 1 (CR1) corresponding to modules 15-17 was overexpressed as a functionally active recombinant protein with N-glycosylation sites ablated by mutagenesis (referred to as CR1 approximately 15-17(-)). A protein consisting of modules 15 and 16 and another corresponding to module 16 were also overexpressed. Comparison of heteronuclear nuclear magnetic resonance (NMR) spectra for the single, double, and triple module fragments indicated that module 16 makes more extensive contacts with module 15 than with module 17. A combination of NMR, differential scanning calorimetry, circular dichroism, and tryptophan-derived fluorescence indicated a complex unfolding pathway for CR1 approximately 15-17(-). As temperature or denaturant concentration was increased, the 16-17 junction appeared to melt first, followed by the 15-16 junction, and module 17 itself; finally, modules 15 and 16 became denatured. Modules 15 and 16 adopted an intermediate state prior to total denaturation. These results are compared with a previously published study [Clark, N. S., Dodd, I, Mossakowska, D. E., Smith, R. A. G., and Gore, M. G. (1996) Protein Eng. 9, 877-884] on a fragment consisting of the N-terminal three CR1 modules which appeared to melt as a single unit.