Pyramidal neuron morphogenesis requires a septin network that stabilizes filopodia and suppresses lamellipodia during neurite initiation

Pyramidal neurons are a major cell type of the forebrain, consisting of a pyramidally shaped soma with axonal and apicobasal dendritic processes. It is poorly understood how the neuronal soma develops its pyramidal morphology, while generating neurites of the proper shape and orientation. Here, we discovered that the spherical somata of immature neurite-less neurons possess a circumferential wreath-like network of septin filaments, which promotes neuritogenesis by balancing the protrusive activity of lamellipodia and filopodia. In embryonic rat hippocampal and mouse cortical neurons, the septin wreath network consists of curvilinear filaments that contain septins 5, 7, and 11 (Sept5/7/11). The Sept5/7/11 wreath network demarcates a zone of myosin II enrichment and Arp2/3 diminution at the base of filopodial actin bundles. In Sept7-depleted neurons, cell bodies are enlarged with hyperextended lamellae and abnormally shaped neurites that originate from lamellipodia. This phenotype is accompanied by diminished myosin II and filopodia lifetimes and increased Arp2/3 and lamellipodial activity. Inhibition of Arp2/3 rescues soma and neurite phenotypes, indicating that the septin wreath network suppresses the extension of lamellipodia, facilitating the formation of neurites from the filopodia of a consolidated soma. We show that this septin function is critical for developing a pyramidally shaped soma with properly distributed and oriented dendrites in cultured rat hippocampal neurons and in vivo in mouse perinatal cortical neurons. Therefore, the somatic septin cytoskeleton provides a key morphogenetic mechanism for neuritogenesis and the development of pyramidal neurons.

Difluoromethylornithine (DFMO) Enhances the Cytotoxicity of PARP Inhibition in Ovarian Cancer Cells

Ovarian cancer accounts for 3% of the total cancers in women, yet it is the fifth leading cause of cancer deaths among women. The BRCA1/2 germline and somatic mutations confer a deficiency of the homologous recombination (HR) repair pathway. Inhibitors of poly (ADP-ribose) polymerase (PARP), another important component of DNA damage repair, are somewhat effective in BRCA1/2 mutant tumors. However, ovarian cancers often reacquire functional BRCA and develop resistance to PARP inhibitors. Polyamines have been reported to facilitate the DNA damage repair functions of PARP. Given the elevated levels of polyamines in tumors, we hypothesized that treatment with the polyamine synthesis inhibitor, α-difluoromethylornithine (DFMO), may enhance ovarian tumor sensitivity to the PARP inhibitor, rucaparib. In HR-competent ovarian cancer cell lines with varying sensitivities to rucaparib, we show that co-treatment with DFMO increases the sensitivity of ovarian cancer cells to rucaparib. Immunofluorescence assays demonstrated that, in the presence of hydrogen peroxide-induced DNA damage, DFMO strongly inhibits PARylation, increases DNA damage accumulation, and reduces cell viability in both HR-competent and deficient cell lines. In vitro viability assays show that DFMO and rucaparib cotreatment significantly enhances the cytotoxicity of the chemotherapeutic agent, cisplatin. These results suggest that DFMO may be a useful adjunct chemotherapeutic to improve the anti-tumor efficacy of PARP inhibitors in treating ovarian cancer.

Three-dimensional visualisation of the feto-placental vasculature in humans and rodents

Adequate development of the feto-placental circulation is critical for placental exchange function and healthy fetal growth. Understanding the structure of this circulation and how it informs fetal outcomes is important both in the human placenta, and the rodent, a purported comparative experimental model. Vascular casting and micro-CT imaging approaches enable detailed quantification of the complex vascular relationships in the feto-circulation, and provide detailed data to parameterise in silico models. Here, to assist researchers to apply these technically challenging methods we provide detailed approaches to cast and image; 1) human placentas at the cotyledon-level, and 2) whole rodent placentas.

Autosomal dominant tubulointerstitial kidney disease (ADTKD) in Ireland

Introduction: Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a rare genetic cause of renal impairment resulting from mutations in the MUC1, UMOD, HNF1B, REN, and SEC61A1 genes. Neither the national or global prevalence of these diseases has been determined. We aimed to establish a database of patients with ADTKD in Ireland and report the clinical and genetic characteristics of these families.

Methods: We identified patients via the Irish Kidney Gene Project and referral to the national renal genetics clinic in Beaumont Hospital who met the clinical criteria for ADTKD (chronic kidney disease, bland urinary sediment, and autosomal dominant inheritance). Eligible patients were then invited to undergo genetic testing by a variety of methods including panel-based testing, whole exome sequencing and, in five families who met the criteria for diagnosis of ADTKD but were negative for causal genetic mutations, we analyzed urinary cell smears for the presence of MUC1fs protein.

Results: We studied 54 individuals from 16 families. We identified mutations in the MUC1 gene in three families, UMOD in five families, HNF1beta in two families, and the presence of abnormal MUC1 protein in urine smears in three families (one of which was previously known to carry the genetic mutation). We were unable to identify a mutation in 4 families (3 of whom also tested negative for urinary MUC1fs).

Conclusions: There are 4443 people with ESRD in Ireland, 24 of whom are members of the cohort described herein. We observe that ADTKD represents at least 0.54% of Irish ESRD patients.

Validation of carcass lesions as indicators for on-farm health and welfare of pigs

Incorporating indicators for pig health and welfare at meat inspection could reduce the need for on-farm assessments. Skin and tail lesions are important welfare indicators in pigs with good potential to record during meat inspection and could possibly function as iceberg indicators of on farm welfare. The aim of this study was to validate the use of these carcass lesions at meat inspection for the assessment of pig health and welfare on farm. Thirty-one farrow-to-finish pig farms (∼12% of Irish herds) were assessed using an adapted version of the Welfare Quality protocol by inspecting 6 randomly selected pens of pigs in the first weaner (4 to 8 wk), second weaner (8 to 13 wk) and finisher stage (13 to 23 wk). The average prevalence of welfare outcomes for each stage was calculated. One batch of pigs was observed at slaughter and skin and tail lesions were scored according to severity for each carcass. The average prevalence of carcass lesion outcomes was calculated for each farm. Linear regression models were developed to predict the prevalence of each welfare outcome in each stage based on the prevalence of the different carcass lesions. The welfare outcomes of different welfare aspects that were best predicted by abattoir information (highest ) were poor body condition (first weaner stage), bursitis (second weaner stage), huddling (first weaner stage), severe tail lesions (finisher stage) and coughing (second weaner stage). Regression trees and receiver-operating curves (ROC) were used to evaluate the usefulness of carcass lesions as monitoring tools. Receiver-operating curves were created using the 75th percentile to classify farms as a problem farm for these welfare outcomes. Cut-off values of predictive carcass lesion prevalence were similar using both techniques. Models for predicting problem farms with poor body condition, bursitis and severe tail lesions were moderately accurate. Sensitivity and specificity ranged from 75 to 100% and 70 to 87%, respectively at the optimal cut-off value of the predictive carcass lesion prevalence. Results show potential for using carcass skin and tail lesions as iceberg indicators of pig health and welfare on farm. Future work is needed to evaluate the cost of including carcass lesion recording at meat inspection, the cost of failing to identify problem farms and the cost of incorrectly visiting or penalizing problem farms before carcass lesions can be used as welfare indicators in a commercial setting.

Reassessing critical maternal antibody threshold in RhD alloimmunization: a 16-year retrospective cohort study

OBJECTIVE

To determine the critical maternal antibody threshold for specialist referral in cases of RhD alloimmunization.

METHODS

This was a retrospective cohort study, covering a 16-year period at the national tertiary fetal medicine center for management of alloimmunization. Data concerning RhD alloimmunized pregnant women were extracted from an institutional database and maternal anti-D antibody levels were cross-checked with the national reference laboratory. Fetal hemoglobin (Hb) levels were determined only at the first intrauterine transfusion (IUT) and were compared with the pretransfusion maternal anti-D antibody level (IU/mL). Sensitivity, specificity and positive and negative predictive values of maternal antibody thresholds for detecting moderate to severe (Hb ≤ 0.64MoM) fetal anemia were calculated.

RESULTS

Between 1996 and 2011, 66 women underwent a first IUT for RhD alloimmunization at our institution. The highest serum anti-D antibody level was extracted for 208 RhD alloimmunized women who did not require IUT during the last 10 years of the study period. The traditional maternal antibody threshold of > 15 IU/mL failed to detect 20% of cases of moderate to severe fetal anemia. The ≥ 4 IU/mL threshold had 100% sensitivity but a 45% false-positive rate. The optimal anti-D antibody threshold for specialist referral in our population was ≥ 6 IU/mL; at this level, no case of moderate to severe anemia was missed and specificity was 61%. Use of this threshold would have eliminated 10% of referrals to our fetal medicine unit without compromising fetal outcomes.

CONCLUSIONS

Setting the critical maternal RhD antibody level at >15 IU/mL does not provide sufficient sensitivity. The lower threshold of ≥ 4 IU/mL, though sensitive, is associated with a 45% false-positive rate. In our population, a threshold of ≥ 6 IU/mL minimizes false-positive referrals while maintaining 100% sensitivity for moderate to severe fetal anemia.

Differential expression of mitochondrial energy metabolism profiles across the metaplasia-dysplasia-adenocarcinoma disease sequence in Barrett's oesophagus

Contemporary clinical management of Barrett's oesophagus has highlighted the lack of accurate predictive markers of disease progression to oesophageal cancer. This study aims to examine alterations in mitochondrial energy metabolism profiles across the entire disease progression sequence in Barrett's oesophagus. An in-vitro model was used to screen 84 genes associated with mitochondrial energy metabolism. Three energy metabolism genes (ATP12A, COX4I2, COX8C) were significantly altered across the in-vitro Barrett's disease sequence. In-vivo validations across the Barrett's sequence demonstrated differential expression of these genes. Tissue microarrays demonstrated significant alterations in both epithelial and stromal oxidative phosphorylation (ATP5B and Hsp60) and glycolytic (PKM2 and GAPDH) protein markers across the in-vivo Barrett's sequence. Levels of ATP5B in sequential follow up surveillance biopsy material segregated Barrett's non progressors and progressors to HGD and cancer. Utilising the Seahorse XF24 flux analyser, in-vitro Barrett's and adenocarcinoma cells exhibited altered levels of various oxidative parameters. We show for the first time that mitochondrial energy metabolism is differentially altered across the metaplasia-dysplasia-adenocarcinoma sequence and that oxidative phosphorylation profiles have predictive value in segregating Barrett's non progressors and progressors to adenocarcinoma.

A correlation between severe haemolytic disease of the fetus and newborn and maternal ABO blood group

OBJECTIVE

To analyse anti-D quantification levels and frequency of intrauterine transfusion (IUT), per maternal ABO blood group.

BACKGROUND

Maternally derived red cell allo-antibodies can target fetal red cell antigens in utero leading to haemolytic disease and fetal anaemia. When a clinically significant allo-antibody is formed the priority is ascertaining the risk to the fetus and maternal ABO blood groups are not considered relevant.

MATERIALS AND METHODS

This was a 10-year retrospective, observational study carried out on women referred for anti-D quantification (n = 1106), and women whose fetuses required an IUT to treat fetal anaemia (n = 62) due to anti-D, in the Republic of Ireland.

RESULTS

Relative to the overall incidence of RhD allo-immunisation by blood group, women of blood group A were more likely to require IUT compared with those who were blood group O (P = 0.002).

CONCLUSION

It is known that ABO feto-maternal compatibility can influence the incidence and level of red cell allo-antibodies in pregnancy; however, it does not account for the significantly high rate of severe haemolytic disease requiring IUT seen in blood group A women.

Debt crisis ahead for Irish medical students

Internationally medical student debt is a cause of concern. A survey of medical students in UCC (response rate of 191 representing 35% of the EU student cohort) reveals that 34 (26%) of direct entry medicine (DEM) students and 36 (61%) graduate entrants (GEM) have a loan with an anticipated average debt of Euro17,300 and Euro80,000 on graduation respectively. Fifty-three (90%) graduate entrants and 75 (57%) direct entrants revealed that they often worry about their current financial situation. Fifty-three (28%) of students have a part-time job and many were concerned about the degree to which this conflicted with their academic workload. 118 (89%) of school leavers and 48 (81%) graduates received financial assistance from their families to fund their college expenses. Student responses recommended the introduction of a government supported low interest rate loan and other incentives to help service high levels of debt associated with medical education.

Surveying the management practices and research needs of graziers in the New England region of New South Wales

The inaugural committee of the Cicerone Project commissioned a survey of livestock producers in the New England region to determine the research problems and production practices which were of greatest importance to graziers. In addition, an assessment was made of the level of interest livestock producers had in participating in a proposed producer-led research and adoption project. The survey was mailed to livestock producers in five districts across the New England region during October and November 1997. The survey results concerning land and pasture management issues suggested that a majority of livestock producers in the New England region found the challenges of dry seasons, fertiliser use, pasture composition and pasture persistence to be major problems. A further issue identified was the problem of resistance to drenches used for internal parasite control in sheep. It was clear that producers depend largely on pastures as the primary feed source due to the high cost of supplementary feed. There was considerable interest in learning how to fill gaps in the feed supply, and the management of the feed supply through droughts. Thus, one desired focus of future studies was to explore management systems that might improve the productivity, resilience, stability and longevity of pastures in the New England region. In addition, a focus on grazing management and its effects on pastures and on internal parasite control was suggested by survey respondents. Of the 316 responses to the survey, 76% expressed interest in becoming involved in the Cicerone Project, confirming the desirability of forming a producer-led research and adoption network within the New England region. One hundred and eighty-one respondents expressed an interest in becoming partner members, 100 respondents indicated they were interested in having their farm included in a network, while 139 people were interested in attending regional workshops where further details about the nature of the Cicerone Project would be developed. The survey was clearly of interest to commercial-scale livestock producers as the average size of respondents’ sheep flocks and cattle herds was over 5000 and 500, respectively. The results of this survey provided empirical evidence to support the formation of the Cicerone Project, which was created in 1998 following the approval of a business plan by the primary funding agency, the Woolmark Co.

Mice lacking the Raf-1 kinase inhibitor protein exhibit exaggerated hypoxia-induced pulmonary hypertension

BACKGROUND AND PURPOSE

Increased pulmonary vascular remodelling, pulmonary arterial pressure and pulmonary vascular resistance characterize the development of pulmonary arterial hypertension (PAH). Activation of the Raf/mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)1/2 is thought to play an important role in PAH and Raf-1 kinase inhibitor protein (RKIP), negatively regulates this pathway. This study investigated whether genetic deletion of RKIP (and hence ERK1/2 up-regulation) resulted in a pulmonary hypertensive phenotype in mice and investigated a role for RKIP in mitogen-regulated proliferative responses in lung fibroblasts.

EXPERIMENTAL APPROACH

Pulmonary vascular haemodynamics and remodelling were assessed in mice genetically deficient in RKIP (RKIP-/-) after 2 weeks of either normoxia or hypoxia. Immunoblotting and immunohistochemistry were used to examine phosphorylation of Raf-1, RKIP and ERK1/2 in mouse pulmonary arteries. In vitro, RKIP inhibition of mitogen signalling was analysed in CCL39 hamster lung fibroblasts.

KEY RESULTS

RKIP-/- mice demonstrated elevated indices of PAH and ERK1/2 phosphorylation compared with wild-type (WT) mice. Hypoxic RKIP-/- mice exhibited exaggerated PAH indices. Hypoxia increased phosphorylation of Raf-1, RKIP and ERK1/2 in WT mouse pulmonary arteries and Raf-1 phosphorylation in RKIP-/- mouse pulmonary arteries. In CCL39 cells, inhibition of RKIP potentiated mitogen-induced proliferation and phosphorylation of RKIP, and Raf-1.

CONCLUSIONS AND IMPLICATIONS

The lack of RKIP protein resulted in a pulmonary hypertensive phenotype, exaggerated in hypoxia. Hypoxia induced phosphorylation of RKIP signalling elements in WT pulmonary arteries. RKIP inhibition potentiated mitogen-induced proliferation in lung fibroblasts. These results provide evidence for the involvement of RKIP in suppressing the development of hypoxia-induced PAH in mice.

An integrative computational model for intestinal tissue renewal

OBJECTIVES

The luminal surface of the gut is lined with a monolayer of epithelial cells that acts as a nutrient absorptive engine and protective barrier. To maintain its integrity and functionality, the epithelium is renewed every few days. Theoretical models are powerful tools that can be used to test hypotheses concerning the regulation of this renewal process, to investigate how its dysfunction can lead to loss of homeostasis and neoplasia, and to identify potential therapeutic interventions. Here we propose a new multiscale model for crypt dynamics that links phenomena occurring at the subcellular, cellular and tissue levels of organisation.

METHODS

At the subcellular level, deterministic models characterise molecular networks, such as cell-cycle control and Wnt signalling. The output of these models determines the behaviour of each epithelial cell in response to intra-, inter- and extracellular cues. The modular nature of the model enables us to easily modify individual assumptions and analyse their effects on the system as a whole.

RESULTS

We perform virtual microdissection and labelling-index experiments, evaluate the impact of various model extensions, obtain new insight into clonal expansion in the crypt, and compare our predictions with recent mitochondrial DNA mutation data.

CONCLUSIONS

We demonstrate that relaxing the assumption that stem-cell positions are fixed enables clonal expansion and niche succession to occur. We also predict that the presence of extracellular factors near the base of the crypt alone suffices to explain the observed spatial variation in nuclear beta-catenin levels along the crypt axis.

Assessing Effect of the Migration of A Paraffin Wax on the Surface Free Energy of Natural Rubber

The effect of the migration of paraffin wax on the surface free energy of natural rubber (NR) was investigated. The rubber was mixed with the wax and then stored at ambient temperature for up to 168 hrs before its surface free energy was measured using contact angle measurement. Static secondary ion mass spectrometry was also used to provide a chemical fingerprint of the rubber surfaces. The surface free energy decreased as a function of storage time because of the migration of the wax to the rubber surface. The highest rate of reduction was recorded up to 3 hrs and thereafter, the surface free energy decreased at a much slower rate, reaching a plateau after 48 hrs in storage. In total, the surface free energy reduced by approximately 46% as a result of the migration of the wax to the rubber surface. The reduction in surface free energy could adversely affect ability of the rubber to stick to itself and to other dissimilar elastomers.

Sentinel lymph node biopsy in patients with a needle core biopsy diagnosis of ductal carcinoma in situ: is it justified?

BACKGROUND

The incidence of ductal carcinoma in situ (DCIS) has increased markedly with the introduction of population-based mammographic screening. DCIS is usually diagnosed non-operatively. Although sentinel lymph node biopsy (SNB) has become the standard of care for patients with invasive breast carcinoma, its use in patients with DCIS is controversial.

AIM

To examine the justification for offering SNB at the time of primary surgery to patients with a needle core biopsy (NCB) diagnosis of DCIS.

METHODS

A retrospective analysis was performed of 145 patients with an NCB diagnosis of DCIS who had SNB performed at the time of primary surgery. The study focused on rates of SNB positivity and underestimation of invasive carcinoma by NCB, and sought to identify factors that might predict the presence of invasive carcinoma in the excision specimen.

RESULTS

7/145 patients (4.8%) had a positive sentinel lymph node, four macrometastases and three micrometastases. 6/7 patients had invasive carcinoma in the final excision specimen. 55/145 patients (37.9%) with an NCB diagnosis of DCIS had invasive carcinoma in the excision specimen. The median invasive tumour size was 6 mm. A radiological mass and areas of invasion <1 mm, amounting to "at least microinvasion" on NCB were predictive of invasive carcinoma in the excision specimen.

CONCLUSIONS

SNB positivity in pure DCIS is rare. In view of the high rate of underestimation of invasive carcinoma in patients with an NCB diagnosis of DCIS in this study, SNB appears justified in this group of patients.

Trends in the prevalence of adolescent births in Antigua and Barbuda over 35 years

A retrospective study was undertaken to determine trends in teenage births in Antigua and Barbuda from 1969 to 2003. Maternity Ward records were reviewed at Holberton Hospital, site of over 90% of deliveries in Antigua and Barbuda. Maternal age for all births were included. The estimated population in Antigua and Barbuda increased from 60,159 in 1969 to 69,866 in 1998, with no suspected change in age-group or gender distribution. Births to mothers 12-13, 14-15, 16-17 and 18-19 years old were analyzed separately. Yearly birth totals for the 10-year period from 1969 to 1973 and 1999 to 2003 were compared using student t test analysis. The total number of births averaged 1075 per year with no change in trend. For females aged 12 and 13 years, there was no change in births from 1969 to 1978 compared with 1994 to 2003. For females aged 14 years, there was a 54% drop; for females aged 15 years, a 59% drop; for females aged 16 years, a 53% drop; for females aged 17 years, a 51% drop; for females 18 years, a 37% drop and for females aged 19 years, a 30% drop, while births to mothers > or = 20 years increased 25%. The decrease for all teen births was 42% from 1969-1978 to 1994-2003. Teen births accounted for 29% of all births at Holberton in 1969 to 1973 but only 16% of births in 1999 to 2003. In conclusion, Antigua and Barbuda has seen a marked drop of 42% in teenage deliveries, including a 53% drop in school-aged teens from 1969 to 2003. Explanations include factors such as economic, social, educational and medical developments.

Liquid-based cytology improves productivity in cervical cytology screening

OBJECTIVES

The ThinPrep test was introduced into our institution on a phased basis over 3 years between January 2002 and December 2004. This study set out to assess its effect on productivity (as measured by output of cases per medical scientist per day) during the changeover period. Numbers of high and low-grade lesions and of unsatisfactory slides were also monitored.

METHODS

The percentage conversion from conventional preparation to liquid-based cytology (LBC) and output of cases per medical scientist per day were calculated from our database at 6-month intervals. The average backlog, average number of cases received per month and percentage of unsatisfactory and abnormal cases were calculated similarly.

RESULTS

Over the study period 92 084 cases were received. The percentage of cases using ThinPrep increased: from 9% in January 2002 to 73% in December 2004. During the study there was an increase in output from 17.0 to 22.3 cases per medical scientist per day, representing a 31% improvement at 73% conversion. Numbers of unsatisfactory cases decreased substantially and the numbers of low and high-grade diagnoses were relatively constant.

CONCLUSIONS

The change to ThinPrep has improved productivity and decreased the number of unsatisfactory cases. There was no adverse effect on quality during the changeover.

Decreasing nosocomial urinary tract infection in a large academic community hospital

Urinary Tract Infection (UTI) is the second most prevalent complication at Lehigh Valley Hospital and Health Network, occurring in 3% of all patients admitted over a 12-month period and contributing to a significant increase in costs. Utilizing data from CareScience's Care Management System, an online decision support tool, in conjunction with hospital laboratory data, and without manual chart review, approximately 20% of all UTIs diagnosed were found to be potentially nosocomial, and were often treated with an expensive broad-spectrum antibiotic. A multidisciplinary hospital committee developed interventions to study and address these findings. The National Nosocomial Infection Surveillance program was initiated on selected units of the hospital; strict catheter placement guidelines and a postoperative urinary retention protocol were developed to minimize catheter use and dwell time, a cost-benefit analysis was conducted, antibiotic use for UTIs was evaluated, and system-wide education was conducted for physicians, residents, and nurses.

Pressure ulcers and spinal-cord injury: incidence among admissions to the Irish national specialist unit

Unlike many other countries, Ireland does not have a pathway to facilitate rapid transfer to its national spinal injuries unit. This retrospective study investigated the effect of this on the incidence of pressure ulceration in new admissions to the unit.

Gene profiling of in vitro and in vivo models of delayed neutrophil apoptosis: a common pathway?

Mechanisms responsible for the termination of an inflammatory response include the activation of a genetic programme of cellular suicide termed apoptosis, which leads to the elimination of the cellular effectors of acute inflammation, particularly the neutrophil. However, delays in this response result in the persistence of inflammation and the development of inflammatory disorders. Understanding the mechanism that inhibits the process of cell death may be helpful in the treatment of inflammatory disorders. Inflammatory cytokines have been shown to inhibit apoptosis through stabilization of the mitochondria and inhibition of the caspase cascade. To date, how these processes are inhibited remains the central question. We hypothesize that the decision for the delay in neutrophil apoptosis is made through signals delivered on the cell surface, which activate combinations of specific genes that inhibit the cell death pathway. Gene chip microarray experiments were performed in in vivo and in vitro models of delayed neutrophil apoptosis. Analysis has yielded changes in a large number of genes involved in inflammation, metabolism, signalling, mitochondrial function and apoptosis. A number of genes have been identified as suitable targets responsible for the regulation of neutrophil apoptosis and their expression was confirmed by real-time PCR and explored at the level of the protein. Their functional role in the apoptotic response is now being determined. One significant finding is that the gene patterns of delay in vitro and in vivo appear to be different, indicating the possibility for different pathways regulating the delay in neutrophil apoptosis.

Use of an improved Watusi collar to manage pediatric neck burn contractures

Burns to the neck present a serious challenge to the pediatric burn team. Even when full neck range of motion is maintained, scarring may lead to banding and a loss of the neck's natural contour. Conventional thermoplastic neck conformers have been used to maintain neck position and provide pressure to maturing scars, but they are rigid and limit functional mobility. This is of particular concern in the pediatric population where limiting neck mobility can disrupt the development of sensory and motor patterns that are essential to normal developmental progression. The Multi-Ring Watusi collar is a flexible neck orthosis that allows mobility and provides circumferential pressure to the neck. We modified this collar to improve its comfort, cosmetic appearance and ease in donning/doffing. The improved Watusi collar is a flexible splint that supports neck position, provides circumferential pressure, and allows for functional neck mobility.

Dynamics of the 16O(e, e'p) reaction at high missing energies

We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25<E(m)<50 MeV and P(m) approximately 60 MeV/c, the reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.

Before you touch that keyboard

New technology often gives rise to new health and safety concerns. The Model-T didn't come equipped with a seatbelt; now it is standard equipment. For years, bike helmets were purely optional; now many jurisdictions legislate their use. We wear seatbelts and helmets to prevent injuries, yet we spend hours each day at a potentially hazardous activity--keyboarding--with absolutely no thought to our own health and safety. This is starting to take a toll.

Thrombocytopenia

Determining the true cause of thrombocytopenia is a difficult and challenging clinical problem. Thrombocytopenia results from various causes, but ultimately occurs when platelets are destroyed, sequestered in the body, or not produced. The differential diagnosis of thrombocytopenia is extensive and complex, and there is a significant overlap among disorders. The advanced practice nurse must take a holistic approach to the patient, eliciting a detailed history and performing a comprehensive physical examination with special emphasis on the skin, abdominal, lymph node and neurologic consideration.

TISSUE PRESSURES IN PYOGENIC FLEXOR TENOSYNOVITIS OF THE FINGER

We investigated 14 patients with pyogenic flexor tenosynovitis for increased tissue pressures in involved digits. All showed raised pressures, in eight to 30 mmHg or more. These levels are consistent with a compartment syndrome.

We describe the results of a modified operative technique which includes irrigation of the sheath and the leaving open of a lateral incision. This also allows early active mobilisation of the finger and has given satisfactory early results.

Tissue pressures in pyogenic flexor tenosynovitis of the finger. Compartment syndrome and its management

We investigated 14 patients with pyogenic flexor tenosynovitis for increased tissue pressures in involved digits. All showed raised pressures, in eight to 30 mmHg or more. These levels are consistent with a compartment syndrome. We describe the results of a modified operative technique which includes irrigation of the sheath and the leaving open of a lateral incision. This also allows early active mobilisation of the finger and has given satisfactory early results.

Differences in participation in experimental drug trials among persons with AIDS

To measure participation in experimental drug trials among persons with acquired immunodeficiency syndrome (AIDS), we interviewed 4,604 persons at least 18 years of age who were reported to have AIDS to 11 state and city health departments in the United States. Ten percent reported that they were currently in a trial. Current enrollment differed significantly (p < 0.05) by race/ethnicity (blacks, 5%; whites, 14%; Hispanics, 15%), gender (women, 7%; men, 11%), exposure mode (injection drug use, 5%, men who have sex with men, 14%), annual household income (< $10,000, 8%, > or = $10,000, 14%), education (< 12 years, 6%; > or = 12 years, 12%), health care (no regular care, 1%, public care, 8%; private care, 17%), and time since AIDS diagnosis (< or = 6 months, 9%; > 6 months, 12%). Adjusting for all factors and time since AIDS diagnosis, blacks (adjusted odds ratio [AOR] = 0.35, 95% confidence interval [CI] 0.26, 0.47), persons with less than 12 years of education (AOR = 0.71, CI 0.53, 0.96), and those without regular health care (AOR = 0.24, CI 0.10, 0.61) remained less likely to be in a trial. Blacks, those with less than 12 years of education, and persons without regular health care were less likely than other persons with AIDS to be currently enrolled in AIDS trials. To increase enrollment of these persons, researchers must address barriers to participation for these groups.

HIV testing patterns: where, why, and when were persons with AIDS tested for HIV?

OBJECTIVE

To describe the location of, primary reason for, and time between the first positive HIV test and AIDS diagnosis in a sample of persons with newly diagnosed AIDS.

DESIGN

Interviews supplementing information routinely collected through AIDS case reporting.

SETTING

Eleven US states and cities.

PATIENTS

Persons with AIDS (2441) diagnosed between January 1990 and December 1992.

MAIN OUTCOME MEASURES

Location of first positive HIV test, primary reason for testing, and time interval between first positive HIV test and AIDS diagnosis.

RESULTS

Overall, persons were tested late in their course of HIV infection: 36% were tested for HIV within 2 months and 51% within 1 year of their AIDS diagnosis. Sixty-five per cent were HIV-tested in acute health-care settings: 33% in hospitals, 28% in physicians' offices, and 4% in emergency departments. Testing during hospitalization was most common among injecting drug users (43%) and persons infected through heterosexual contact (50%). Persons primarily sought HIV testing because of illness (58%); other reasons included being in a known risk group (13%) and having had a known HIV-infected sex partner (8%). Testing because of being in a known risk group was least common among persons infected through heterosexual contact (1%). Among persons in these exposure categories, testing differed by race/ethnicity.

CONCLUSION

Most persons with AIDS were tested relatively late in their course of HIV infection, in acute health-care settings, and because of illness. Not knowing one's serostatus precludes early medical intervention and may increase transmission.

Stimulus-response compatibility in a small sample of cerebral palsied adults

Stimulus-response compatibility refers to the correspondence between a sensory event and the motor response which it specifies. A discrete aimed movement task with two conditions of stimulus-response compatibility tested whether higher compatibility would decrease the reaction time of 5 subjects with normal movement and 6 subjects with cerebral palsy. A board with 3 distances (13.5, 28.0, 40.5 cm) along each of 3 rays (45 degrees, 90 degrees, 135 degrees) provided 9 target sites for a detachable leaf switch. A light on the switch was turned off or on for the low or high compatibility condition. The independent variables were the Index of Difficulty, target position and compatibility. The dependent variables were reaction time and movement time. The reaction times for both groups were less during the high compatibility condition than during the low compatibility condition as shown by a t test for differences between means. Multiple regression analyses showed that reaction time of the normal group was a positive linear function of compatibility and movement time was a positive linear function of the Index of Difficulty for both groups and of position for the normal group, 3 normal subjects and 2 cerebral palsied subjects. There were indications of ballistic rather than aimed movements. The results are discussed with regard to the role of visual fixation in aimed movement, the similarities between groups in conformance to Fitts' Law and differences between groups in reaction and movement times.

The effect of simulated fracture-angulations of the tibia on cartilage pressures in the knee joint

The effects of angular deformities of the tibia on the contact areas and pressures on cartilage in the knee were measured with use of pressure-sensitive film. Six cadaver knees were mounted in a test-frame, such that the offset and tilt of the knee relative to the load-axis simulated that due to angular deformities of the tibia of 5, 10, 15, or 20 degrees of varus or valgus at the levels of the proximal, middle, and distal thirds. Angulation had little effect on the contact area. The change in pressure was least for fractures of the distal third and greatest for fractures of the proximal third. For example, a 20-degree angulation of the distal third increased the maximum contact pressure by an average of 26 per cent in the compartment toward the load-axis and reduced it by 32 per cent in the opposite compartment. With an angulation of 20 degrees at the level of the proximal third of the tibia, the increase in pressure averaged 106 per cent and the decrease averaged 89 per cent. The changes in pressure with fractures at the middle third were between these extremes.