The pulvinar sign on magnetic resonance imaging in variant Creutzfeldt-Jakob disease

BACKGROUND

There is a need for an accurate non-invasive diagnostic test for variant Creutzfeldt-Jakob disease (vCJD). We investigated the sensitivity and specificity of bilateral pulvinar high signal on magnetic resonance imaging (MRI) for the diagnosis of vCJD.

METHODS

MRI from patients with vCJD and controls (patients with suspected CJD) were analysed. Scans were reviewed on two separate occasions by two neuroradiologists and scored for the distribution of changes, and likely final diagnosis. Scans from vCJD cases were reassessed to reach a consensus on all abnormalities.

FINDINGS

We analysed 36 patients and 57 controls. vCJD patients were correctly identified based on bilateral pulvinar high signal in 29 of 36 and 32 of 36 cases on the first assessment by the two radiologists, and 32 of 36 and 31 of 36 on their second assessment. Bilateral increased pulvinar signal was identified in one of 57 and one of 57 controls on the first assessment and two of 57 and three of 57 controls on the second assessment. These reported changes in controls were graded as minimal/equivocal in six of seven patients and moderate in one (<0.5% of all control assessments). 80% of the assessments in vCJD cases were graded as moderate or substantial. On consensus review, 28 of 36 cases and none of 57 controls had prominent bilateral pulvinar signal-sensitivity 78% (95% CI 60-90%) and specificity 100% (95% CI 94-100%). Other common MRI features of vCJD were medial thalamic and periaqueductal grey matter high signal, and the notable absence of cerebral atrophy. Pulvinar high signal correlated with histological gliosis.

INTERPRETATION

In the appropriate clinical context the MRI identification of bilaterally increased pulvinar signal is a useful non-invasive test for the diagnosis of vCJD.

Epithelial Na+ channels and stomatin are expressed in rat trigeminal mechanosensory neurons

Caenorhabditis elegans MEC-4 and MEC-10 are subunits of the degenerin/epithelial Na+ channel (DEG/ENaC) ion channel superfamily thought to be associated with MEC-2 (a stomatin-like protein) in a mechanotransducing molecular complex in specialized touch sensory neurons. A key question is whether analogous molecular complexes in higher organisms transduce mechanical signals. To address this question, we selected mechanoreceptors of the rat vibrissal follicle-sinus complex in the mystacial pad and the trigeminal ganglia for an immunocytochemical and molecular biological study. RT-PCR of poly(A+) mRNA of rat trigeminal ganglia indicated that alpha-, beta-, and gamma-ENaC and stomatin mRNA are expressed in rat trigeminal ganglia. Using immunocytochemistry, we found that alpha-, beta-, and gamma-ENaC subunits and stomatin are localized in the perikarya of the trigeminal neurons and in a minor fraction of their termination site in the vibrissal follicle-sinus complex, where longitudinal lanceolate endings are immunopositive. We conclude that alpha-, beta-, and gamma-ENaC subunits as well as the candidate interacting protein stomatin are coexpressed in a mammalian mechanoreceptor, a location consistent with a possible role in mechanotransduction.

Early echocardiographic changes and survival following renal transplantation

BACKGROUND

Left ventricular hypertrophy, ventricular dilatation and poor systolic function prior to renal transplantation are associated with increased mortality. However, whether the improvement in these echocardiographic indices that is reported to follow renal transplantation improves patient survival has not been investigated.

METHODS

We studied 67 patients who underwent renal transplantation in our unit between 1988 and 1990 and in whom echocardiography was performed immediately prior to transplant surgery and 4 months later. Pre- and post-transplantation echocardiographic parameters were compared between the 20 patients who have since died and surviving patients and a descriptive survival analysis was performed.

RESULTS

Following transplantation there was no significant change in left ventricular mass index (LVMI) or end diastolic diameter (EDD). End systolic diameter (ESD) improved in 60% of patients (median 3.3 vs 3. 7 cm; P=0.031) as did fractional shortening in 67% (0.33 vs 0.29; P=0.001). However, improvement was not associated with survival benefits. We also found that prior to transplantation, fractional shortening, ESD and EDD were strongly associated with outcome; this was no longer the case following transplantation. In contrast, LVMI provided a stronger association with adverse outcome (albeit of limited statistical significance) following transplantation.

CONCLUSIONS

In this Preliminary Report, we conclude that echocardiographic parameters are associated with adverse outcome in patients receiving renal replacement therapy (RRT). Different echocardiographic parameters are associated with adverse outcome before and after renal transplantation and improvement of pre-transplant abnormalities (e.g. poor LV systolic function) following transplantation does not necessarily confer survival benefits. Whether this is a genuine observation or a reflection of the interpretation of echocardiographic measurements in dialysis patients requires further investigation.

Mode-hop-free single-longitudinal-mode erbium-doped fiber laser frequency scanned with a fiber ring resonator

We describe the experimental construction of a single-longitudinal-mode erbium-doped fiber ring laser equipped with a ring resonator filter. The system is designed to avoid mode hopping and can be frequency scanned for spectroscopic sensor applications. We modified a conventional ring resonator filter to have the capability to reduce transmittance of unwanted modes, which is essential for frequency scanning without mode hopping.

Does spinal instrumentation influence the healing process of posterolateral spinal fusion? An in vivo animal model

STUDY DESIGN

An in vivo sheep model was used to investigate the effect of spinal instrumentation on the healing process of posterolateral spinal fusion.

OBJECTIVES

To examine the role of spinal instrumentation during the healing process of posterolateral fusion.

SUMMARY OF BACKGROUND DATA

In long bone fractures, internal fixation improves the union rate but does not accelerate the healing process. Spinal instrumentation also improves the fusion rate in spinal arthrodesis. However, it remains unclear whether the use of spinal instrumentation expedites the healing process of spinal fusion.

METHODS

Sixteen sheep underwent posterolateral spinal arthrodeses at L2-L3 and L4-L5 using equal amounts of autologous bone. One of those segments was selected randomly to be augmented with transpedicular screw fixation (Texas Scottish Rite Hospital spinal system). The animals were killed at 8 weeks or 16 weeks after surgery. Fusion status was evaluated by biomechanical testing, manual palpation, plain radiography, computed tomography, and histology.

RESULTS

Instrumented fusion segments demonstrated significantly higher stiffness than did uninstrumented fusions at 8 weeks after surgery. Radiographic assessment and manual palpation showed that the use of spinal instrumentation improved the fusion rate at 8 weeks (47% versus 38% in radiographs, 86% versus 57% in manual palpation). Histologically, the instrumented fusions consisted of more woven bone than the uninstrumented fusions at 8 weeks after surgery. The 16-week-old fusion mass was diagnosed biomechanically, radiographically, and histologically as solid, regardless of pedicle screw augmentation.

CONCLUSION

The current study's results demonstrated that spinal instrumentation creates a stable mechanical environment to enhance the early bone healing of spinal fusion.

Hereditary dehydrated and overhydrated stomatocytosis: recent advances

The hereditary stomatocytoses and allied disorders are genetic defects of the erythrocyte membrane that result in abnormal permeability to the univalent cations Na+ and K+. Although rare, these conditions reflect abnormalities in physiologic mechanisms that are of paramount interest. All cases (as defined here) show increased plasma membrane permeability to Na+ and K+ and, to a greater or lesser degree, stomatocytic morphology. Dehydrated hereditary stomatocytosis, the most common form of hereditary stomatocytosis, is more heterogeneous than previously thought and includes kindreds showing pseudohyperkalemia or perinatal edema, or both. The gene responsible for both dehydrated hereditary stomatocytosis and familial pseudohyperkalemia, a nonhemolytic variant that presents with high plasma K+ levels, has been mapped to 16q23-qter. The cause of overhydrated hereditary stomatocytosis remains elusive despite the manifest lack of the enigmatic protein stomatin in the erythrocyte membrane. In all cases where splenectomy has been performed, this procedure has conferred a marked risk for thrombosis in adult life. This finding stresses the importance of diagnostic distinction between these conditions and hereditary spherocytosis.

Adenosine and pediatric supraventricular tachycardia in the emergency department: multicenter study and review

STUDY OBJECTIVE

To determine the frequency of successful cardioversion and the adverse effects of adenosine treatment in pediatric emergency department patients with supraventricular tachycardia (SVT).

METHODS

This was a multicenter descriptive study with both prospective (convenience sample) and retrospective (chart review) patient entry. The setting was 7 urban pediatric EDs with a yearly census range of 22,000 to 70,000 visits. Pediatric patients 18 years of age and younger who received intravenous adenosine for presumed SVT were eligible.

RESULTS

Six investigators from 7 pediatric EDs entered 82 patients with 98 presumed SVT episodes (52 prospective and 46 retrospective) into the study. Twenty-five episodes occurred in children younger than 1 year of age. Eight patients had congenital heart disease, 59 had a history of SVT, 43 were taking cardiac medications (digoxin in 27), 13 had a history of asthma, and 25 presented in compensated cardiogenic shock. A total of 193 intravenous doses of adenosine were administered; doses were classified as low (<.1 mg/kg [n=18]), medium (.1 to <.2 mg/kg [n=116]), or high (>/=.2 mg/kg [n=59]). The dose range was.03 to.5 mg/kg, and only 2 doses were higher than.3 mg/kg. A total of 95 patient-events were determined to be SVT, all but 5 of which were atrioventricular (AV) node-dependent; 3 events were ventricular tachycardia. The overall cardioversion success rate of adenosine was 72% (71/98), and that for AV node-dependent SVT was 79% (71/90). Cardioversion was successful for 4 patient-events at a low dose, 44 at a medium dose, and 23 at a high dose of adenosine. Adverse effects occurred in 22 patients, and no patient had bronchospasm or hemodynamically significant arrhythmia.

CONCLUSION

Intravenous administration of adenosine led to successful cardioversion in 72% of pediatric ED patient-events that were presumed to be SVT. A dose range of.1 to.3 mg/kg was found to be most effective. Adenosine was not associated with significant adverse effects.

Geographical distribution of variant CJD in the UK (excluding Northern Ireland)

BACKGROUND

The agent that causes variant Creutzfeldt-Jakob disease (variant CJD) is indistinguishable from the causative agent of bovine spongiform encephalopathy (BSE). The transmission route by which human beings are infected has not been established. One hypothesis is that cases of variant CJD have resulted from exposure to the BSE agent via rendering plants involved in the production of meat and bone meal, the main vehicle of the BSE epidemic.

METHODS

We identified cases of variant CJD through the National CJD Surveillance Unit, and obtained lifetime residential histories of cases by interviewing a relative. The addresses of all rendering plants in the UK (excluding Northern Ireland) in production in 1988 were available from a survey done in that year. We calculated the distance between each case's place of residence on Jan 1, 1988, and the nearest rendering plant from postcode data, and used data from the 1991 UK census to estimate the population living within various distances of rendering plants. We compared the observed number of cases of variant CJD within a particular distance of a rendering plant with the number expected if there is no association between residential proximity to a rendering plant and the risk of developing variant CJD.

FINDINGS

Up to Aug 31, 1998, 26 cases of variant CJD with onset in the UK (Northern Ireland not included) had been identified. The observed and expected numbers of variant CJD cases living within a specified distance of any rendering plant up to 50 km were almost the same. Two plants in the county of Kent each had four cases within 50 km in 1988, significantly more cases than expected (plant A, 1.04 expected; plant B, 0.74 expected). Multiple significance tests were done, so some tests would be expected to appear significant by chance alone. Computer simulations suggested that the observation of four cases of variant CJD living in an area with a population of 1.5 million (the size of Kent) is not unexpected.

INTERPRETATION

There is no evidence that people with variant CJD tended to live closer than the population as a whole to rendering plants in the 1980s. The reported cluster of variant CJD cases in Kent is most probably a chance finding.

Inactivation of ataxia telangiectasia mutated gene in B-cell chronic lymphocytic leukaemia

BACKGROUND

Patients with the inherited disorder ataxia telangiectasia (A-T) have an increased susceptibility to lymphoid malignancies. In these patients mutations affect both alleles of the A-T gene (ATM). We have looked for mutations in the ATM gene in sporadic cases of B-cell chronic lymphocytic leukaemia (B-CLL).

METHODS

32 cases of B-CLL were analysed by restriction endonuclease fingerprinting to detect mutations within ATM. In six of the cases in which mutations were detected in tumour samples, germline DNA was screened to assess ATM carrier status. The samples in 20 cases were also studied by western blot for abnormal expression of ATM protein.

FINDINGS

Expression of the ATM protein was impaired in eight (40%) of the 20 tumours analysed, being absent in three and decreased in five. Mutations within ATM were detected in six (18%) of the 32 patients. These point mutations, deletions, and one insertion were distributed across the coding sequence of ATM. Germline mutations, which indicate ATM carrier status, were found in two of these six patients compared with a frequency within the general population of below 1 in 200.

INTERPRETATION

Abnormal expression of ATM protein is a frequent finding in B-CLL. Although the precise function of this protein is unknown, it is thought to have a role in programmed cell death, a deficiency of which would fit with the characteristic phenotype of prolonged cell survival seen in B-CLL tumour cells. Our results also suggest that carriers of ATM mutations may be at a particular risk for the development of B-CLL and this may partly explain the known genetic susceptibility to this disease.

A longitudinal study of the relationships between haemostatic, lipid, and oestradiol changes during normal human pregnancy

Increased activation of both blood coagulation and fibrinolysis occurs during normal pregnancy. The responsible mechanisms are unclear, but may include increases in both oestradiol and blood lipids. We, therefore, studied the associations between fasting serum oestradiol, plasma cholesterol and triglyceride, and Factor VII activity, PAI activity, t-PA antigen, fibrin D-dimer, and vWF antigen in 10 women, each sampled on 6 occasions between 10 weeks and 35 weeks during normal pregnancy. Strong and similar individual correlations were observed between increases in FVII, PAI, t-PA and D-dimer (but not vWF) and increases in both oestradiol and triglyceride. Associations between increments in plasma cholesterol and haemostatic factors (except for FVII), were somewhat weaker. We, therefore, suggest that oestradiol-induced hypertriglyceridaemia may be a cause of elevations in plasma Factor VII activity, PAI and t-PA, and fibrin turnover (D-dimer) during normal pregnancy, but is poorly related to the increase in vWF antigen.

Screening for carbon monoxide in children

OBJECTIVE

Carbon monoxide (CO), a colorless, odorless gas, accounts for the majority of fatal poisonings in the United States. To date, few screening studies that evaluate pediatric exposure are available. The objectives of this study were to determine the value of a CO breath analyzer for detecting pediatric CO exposure and to identify potential CO sources.

DESIGN

Prospective screening study.

SETTING

Emergency department of an urban children's hospital.

PATIENTS

A convenience random sample of 470 noncritically ill children, aged five to 20 years, who presented to a pediatric emergency department and could blow into a CO breath analyzer.

INTERVENTION

After informed consent and demographic and clinical variables were ascertained, eligible patients blew into a CO breath analyzer. Those with breath CO levels > or = 9 ppm underwent confirmatory cooximetric analysis of capillary blood. Sources of CO exposure were determined by history and a home-site evaluation by the local gas company. Patients with carboxyhemoglobin (COHb) levels of more than 5% were given normobaric 100% oxygen until their COHb levels were less than 5%.

RESULTS

1.9% (9/470) of patients had elevated breath CO levels and COHb levels by cooximetry. Putative sources of CO exposure were active cigarette smoking for five patients and a faulty furnace in the home for one patient. On the basis of the history, we believe environmental tobacco smoke or automobile exhaust or both contributed to the elevated COHb levels in the other three patients. There was a good correlation between COHb by cooximetry and breath analysis (concordance correlation = 0.739) CONCLUSION: Breath analysis for CO is a convenient tool to estimate exposure and identify older children at risk.

Outpatient continuous intravenous interleukin-2 or subcutaneous, polyethylene glycol-modified interleukin-2 in human immunodeficiency virus-infected patients: a randomized, controlled, multicenter study. Australian IL-2 Study Group

The safety and activity of outpatient-based continuous intravenous interleukin-2 (CIV IL-2) or a slow-release, polyethylene glycol (PEG)-modified IL-2 were studied in human immunodeficiency virus (HIV)-infected persons with CD4 cell counts between 200 and 500/mm3. One hundred fifteen patients were randomized to antiretroviral therapy plus cyclical CIV IL-2 (n = 27), subcutaneous PEG IL-2 (n = 58), or no IL-2 (n = 30). Toxicity withdrawal rates were low (4% for CIV IL-2 and 7% for PEG IL-2). There were median CD4 cell count increases of 359 and 44 cells/mm3 and a decline of 46 cells/mm3 in the 3 groups, respectively, over 1 year (P < .0001 for each intergroup comparison). CD4 cell count increases were greatest in those with lower HIV RNA load. Delayed-type hypersensitivity scores increased and HLA-DR expression on CD8 cells decreased significantly with IL-2 therapy. HIV RNA levels were unaffected. IL-2 therapy may expand the existing immune repertoire but not immediately reconstitute lost immune function.

Chronic multisymptom illness affecting Air Force veterans of the Gulf War

CONTEXT

Gulf War (GW) veterans report nonspecific symptoms significantly more often than their nondeployed peers. However, no specific disorder has been identified, and the etiologic basis and clinical significance of their symptoms remain unclear.

OBJECTIVES

To organize symptoms reported by US Air Force GW veterans into a case definition, to characterize clinical features, and to evaluate risk factors.

DESIGN

Cross-sectional population survey of individual characteristics and symptoms and clinical evaluation (including a structured interview, the Medical Outcomes Study Short Form 36, psychiatric screening, physical examination, clinical laboratory tests, and serologic assays for antibodies against viruses, rickettsia, parasites, and bacteria) conducted in 1995.

PARTICIPANTS AND SETTING

The cross-sectional questionnaire survey included 3723 currently active volunteers, irrespective of health status or GW participation, from 4 air force populations. The cross-sectional clinical evaluation included 158 GW veterans from one unit, irrespective of health status.

MAIN OUTCOME MEASURES

Symptom-based case definition; case prevalence rate for GW veterans and nondeployed personnel; clinical and laboratory findings among veterans who met the case definition.

RESULTS

We defined a case as having 1 or more chronic symptoms from at least 2 of 3 categories (fatigue, mood-cognition, and musculoskeletal). The prevalence of mild-to-moderate and severe cases was 39% and 6%, respectively, among 1155 GW veterans compared with 14% and 0.7% among 2520 nondeployed personnel. Illness was not associated with time or place of deployment or with duties during the war. Fifty-nine clinically evaluated GW veterans (37%) were noncases, 86 (54%) mild-to-moderate cases, and 13 (8%) severe cases. Although no physical examination, laboratory, or serologic findings identified cases, veterans who met the case definition had significantly diminished functioning and well-being.

CONCLUSIONS

Among currently active members of 4 Air Force populations, a chronic multisymptom condition was significantly associated with deployment to the GW. The condition was not associated with specific GW exposures and also affected nondeployed personnel.

Genomewide search for dehydrated hereditary stomatocytosis (hereditary xerocytosis): mapping of locus to chromosome 16 (16q23-qter)

Dehydrated hereditary stomatocytosis, also known as "hereditary xerocytosis," is caused by a red blood cell-membrane defect characterized by stomatocytic morphology, increased mean corpuscular hemoglobin concentration, decreased osmotic fragility, increased permeability to the univalent cations Na+ and K+, and an increased proportion of phosphatidylcholine in the membrane. The clinical presentation is heterogeneous, ranging from mild to moderate hemolytic anemia associated with scleral icterus, splenomegaly, and choletithiasis. Iron overload may develop later in life. The disease is transmitted as an autosomal dominant trait. We recruited a large three-generation Irish family affected with DHS and comprising 23 members, of whom 14 were affected and 9 were healthy. Two additional, small families also were included in the study. The DNA samples from the family members were used in a genomewide search to identify, by linkage analysis, the DHS locus. After the exclusion of a portion of the human genome, we obtained conclusive evidence for linkage of DHS to microsatellite markers on the long arm of chromosome 16 (16q23-q24). A maximum two-point LOD score of 6.62 at recombination fraction .00 was obtained with marker D16S520. There are no recombination events defining the telomeric limit of the region, which therefore is quite large. No candidate genes map to this area.

Effects of hydrotherapy on pressure ulcer healing

Pressure ulcers are a prevalent and potentially serious medical problem encountered in both the medical and rehabilitation settings. Because the progress of rehabilitation is often interrupted by the presence of pressure ulcers, the efficient care of these wounds is of great interest to the rehabilitation team. Patients in two acute care facilities with Stage III or IV pressure ulcers were identified and consented to participate in the study contained herein. All wounds were mechanically debrided of necrotic tissue, and then the patients were randomly assigned to the conservative treatment group (A; n = 18) or the conservative treatment plus whirlpool group (B; n = 24). Conservative treatment included measures to maximize pressure relief and wound care with wet-to-wet dressings using normal saline. The dressings were changed twice daily and when they became soiled. Whirlpool was administered for 20 min per day in Group B patients. Only those patients whose ulcers were followed-up for 2 or more wk were included in the study. Ulcers were then measured by a physician who was blinded as to the treatment groups. Ulcer dimension changes over time were compared between groups. The results indicate that the conservative treatment plus whirlpool group improved at a significantly faster rate than did the conservative treatment only group (P < 0.05).

The new variant form of Creutzfeldt-Jakob disease

A new phenotype of Creutzfeldt-Jakob disease termed new variant Creutzfeldt-Jakob disease (nvCJD) was first described in March 1996. This differs from other forms of CJD in terms of its epidemiology, clinical features and neuropathology. To date 24 cases of this new form of CJD have been described, 23 within the UK. This article describes nvCJD discussing clinical and epidemiological features and discusses possible links with the bovine spongiform encephalopathy epidemic in cattle in the UK.

Influence of polymorphism Q3405E and mutation A3371V in the apolipoprotein B gene on LDL receptor binding

Familial defective apolipoprotein B (FDB) is due to mutations in the apolipoprotein B (apo B) gene at codon 3500 or 3531 that affect low density lipoprotein (LDL) receptor binding. From sequence analysis the putative receptor binding site was believed originally to be upstream from this at residues 3147-3157 and 3357-3367. Using denaturing gradient gel electrophoresis, mutations were sought in codons 3350-3466. This includes the important positively charged residues 3357-3367. DNA from 928 hyperlipidaemic individuals was studied and two hitherto unknown DNA changes were discovered, one of which resulted in an altered amino acid in the apo B. A known polymorphism Q3405E was also detected at a carrier frequency of 1.4%. Using growth of U937 cells as a measure of binding affinity of LDL to its receptor the newly discovered mutant A3371V permitted the same growth as LDL from normolipidaemic individuals of the U937 cells, however, the LDL from Q3405E individuals permitted only 77% of the normal growth (P=0.009).

Cloning of a complementary DNA encoding an Ambystoma mexicanum metallothionein, AmMT, and expression of the gene during early development

We have used a polymerase chain reaction strategy to isolate a metallothionein (MT) cDNA from the amphibian Ambystoma mexicanum (axolotl). This cDNA is 875-bp long and encodes a 60 amino acid protein, AmMT, typical for family 1 MTs. It contains 20 cysteine (Cys) residues that can be aligned with those of other vertebrate MTs. The overall structure of the protein is unique among vertebrates in having only two amino acid residues before the first Cys at the amino-terminal end. Northern analyses showed that AmMT is expressed throughout embryogenesis, giving rise to three mRNA species of 650, 750, and 1,600 nucleotides (nt). The 750 and 1,600 nt transcripts appear to result from differential use of polyadenylation signals, whereas the 650 nt RNA could arise from deadenylation of the 750-nt transcript. Both the 750- and 1,600-nt RNAs were presented in embryos before the mid-blastula transition (MBT). After the MBT, the 750-nt RNA was replaced by the 650-nt RNA which was gradually degraded to undetectable levels in post-neurulation embryos. Levels of the 1,600-nt transcript increased at gastrulation and reach a maximum in Stage 30 embryos. In adult animals, levels of the 750-nt RNA were high in liver and testes, and very low in lung, gut, skin, and oviducts, whereas levels of the 1,600-nt transcript were similar and moderately elevated in all tissues examined. In contrast, in Xenopus laevis, Northern analysis did not detect XIMT-A mRNA in embryos before late neurulation (Stage 24). XIMT-A mRNA levels then increased sharply in Stage 36 hatched embryos at levels similar to those found in adult livers. These results show that AmMT presents a unique expression pattern among metazoans being transcribed as two transcripts differing in the length of their 3' untranslated regions, the levels of which vary during embryogenesis and in adult tissues.

Expect the worse or hope for the best? Prenatal diagnosis of geleophysic dysplasia

Geleophysic dysplasia is a rare, autosomal recessive disorder which causes disproportionate short stature associated with severe physical handicaps, but is compatible with survival into adulthood. We present a case, a first-born child, where genetic counselling difficulties arose following ultrasound recognition of short-limbed dwarfism in association with polyhydramnios and an initial incorrect prenatal diagnosis of lethal chondrodysplasia. After birth of the surviving affected infant, the parents had great difficulty accepting that there had been a prenatal misdiagnosis and they were greatly disappointed by our inability to predict the postnatal survival of an infant to whom no hope of life had previously been given. The correct diagnosis was not made until the proband was nearly 1 year old, and the true prognosis then became clearer. This experience underlines the relative ease of prenatal recognition of skeletal growth abnormalities compared with the considerable difficulties experienced in reaching a precise diagnosis. Thus, following prenatal diagnosis of unspecified chondrodysplasia when parents seek definite information about the prognosis, the temptation to be either overpessimistic or overoptimistic should be avoided.

Investigation of interferometric noise in fiber-optic gas sensors with use of wavelength modulation spectroscopy

We report on interferometric noise limitation of fiber-optic gas sensors with highly coherent lasers and wavelength modulation spectroscopy. Interference between signal wave and reflected waves causes signal fluctuation in the output, which limits the performance of the sensing system. Sensor resolution limited by interferometric noise is calculated for a fiber-optic gas sensor with the Q(6) absorption line of methane gas at approximately 1650 nm. The results are useful for system designers of this particular type of gas sensor.

Limitation of absorption-based fiber optic gas sensors by coherent reflections

We report the noise limitation of fiber optic gas sensors with highly coherent laser sources. Interference between signal and reflected waves causes signal fluctuation in the output; this limits the performance of the sensing system. Sensor resolutions limited by coherent reflections are calculated and compared with experimental results.

Changes in empowerment: effects of participation in a lay health promotion program

The Camp Health Aide Program is a lay health promotion program for migrant and seasonal farmworkers. The program increases access to health care while facilitating leadership development and empowerment of individual farmworkers through training and experience as lay health promoters (camp health aides [CHAs]). This article describes a study which documents impacts on the CHAs of working as lay health promoters in terms of changes in personal empowerment. The authors developed a working definition of personal empowerment and interviewed 27 CHAs at three program sites (Arizona, New Jersey, and Florida) at three different times. CHAs are grouped in five descriptive categories reflecting varying degrees of change in empowerment over this period. Of the total group of 27 CHAs, 24 exhibited some increase in personal empowerment during the study period. These changes are described in detail, and implications are discussed.

Specialisation in nursing: implications in Australia

Specialisation in professional nursing practice requires the collaborative development of appropriate processes, systems and pathways. Orderly development ensures that the unique knowledge, skills and attributes of specialist nurses are revealed, thereby empowering nurses and adding depth and breadth to specialist nursing knowledge and clinical practice.

HIV antibodies: further questions and a plea for clarification

The existence of specific antibody/protein reactions is the crucial assumption underlying proof of HIV isolation, proof of HIV infection and the causative role of HIV in AIDS. However, since 1. antibodies which react with the 'HIV' proteins arise following allogenic stimuli in non-HIV-infected animals and humans, as well as in mice and humans with autoimmune disorders; antibodies to antigens from both mycobacteria and yeasts cross-react with HIV env and gag proteins; 2. individuals belonging to the AIDS risk groups are subjected to allogenic stimuli and have high levels of autoimmune antibodies, while the vast majority of patients in the AIDS risk groups are infected with either or both mycobacteria or yeasts; the evidence for the existence of HIV and its putative role in AIDS must be reappraised.

Comparison of biochemical markers of bone turnover in Paget disease treated with pamidronate and a proposed model for the relationships between measurements of the different forms of pyridinoline cross-links

We have compared the use of new markers of bone turnover in the assessment and treatment of Paget disease and made observations on the mechanisms of bone resorption. Urine hydroxyproline (Hyp) as a bone resorption marker and serum alkaline phosphatase (ALP) as a bone formation marker have traditionally been used to biochemically assess and monitor treatment of Paget disease. Hyp and total ALP were compared with total urine pyridinoline (Pyd) and deoxypyridinoline (Dpd), free urine Pyd and Dpd, urine type I collagen N-terminal cross-linked telopeptide (NTX), type I collagen C-terminal propeptide (PICP), serum osteocalcin, and bone ALP in Paget patients treated with pamidronate. Patients were divided into three biochemical severity-based treatment groups by their fasting urine hydroxyprolline excretion (HypE) levels (Le., group 1, HypE < 5.0 mumol/l of glomerular filtrate [GF]; group 2, HypE of 5.0-9.9 mumol/l of GF; group 3, HypE > 10 mumol/l of GF). Group 1 received one 60 mg intravenous infusion of pamidronate, and groups 2 and 3 received four and six 60 mg infusions at weekly intervals, respectively. Fasting serum and morning urine specimens were taken before and at 2, 6, 13, and 26 weeks after starting treatment. Baseline Z scores were used to compare separation of patient results from normal, and the difference in Z scores from baseline to 13 weeks was used to compare response to treatment. Baseline discrimination and response to treatment at all disease activity levels was greatest for NTX and was poor for osteocalcin, PICP, and C-terminal cross-linked telopeptide of type I collagen (ICTP). The other markers showed good discrimination and response at medium and high levels of disease activity. NTX, total Pyd and Dpd, free Pyd and Dpd, and ICTP are all pyridinoline cross-link-based markers, but discrimination and response by NTX was generally much greater than for the others. Determination of the mechanism of the difference between NTX and other cross-link measures is necessary for appropriate use of the markers and may also lead to a better understanding of the bone resorption process. It has been proposed that the greater sensitivity and discrimination of NTX is because it is more bone-specific than the other cross-link markers with significant amounts of free Pyd and Dpd coming from nonbone sources. We propose another model where the proportion of peptide-bound cross-links such as NTX may be increased in high bone turnover states partly due to a rate-limiting step in their degradation to free cross-links. Conditions with high bone resorption rates would have high levels of NTX that would decline rapidly when resorption rates fall to a level where the capacity to degrade NTX matches the rate of production.

Patient outcomes after reoperation on the lumbar spine

A consecutive series of thirty-nine patients who had had a reoperation of the lumbar spine was followed up for an average of forty-eight months (range, twenty-four to eighty-six months). The patients were evaluated with regard to pain, functional status, and work status. Twenty-eight patients (72 percent) had a successful outcome, as determined by their ability to return to work, their lack of a need for narcotic analgesics, and their satisfaction with the operative results. Factors that were significantly associated with a successful outcome included a younger age (p < 0.02), working outside the home (p < 0.05), an initial period of improvement after the previous (index) operation (p < 0.01), fewer spinal levels operated on previously (p < 0.05), and a revision procedure incorporating anterior interbody arthrodesis (p < 0.02).

Resistance to Onchocerca volvulus: differential cellular and humoral responses to a recombinant antigen, OvMBP20/11

Persons putatively immune (PI) to Onchocerca volvulus (Ov) infection were identified in Ecuador on the basis of epidemiologic, clinical, and parasitologic findings. Immune responses of PI subjects to a recombinant onchocercal protein, OvMBP20/11, were determined and compared with those of a comparable infected (INF) group from the same Ov-endemic area. PI subjects had significantly less antibody reactivity to this molecule; however, not all INF subjects had an antibody response. IgG1 and IgG4 were the predominant IgG subclasses induced to this molecule, and the amount of IgG1 produced was the only significant difference between the PI and INF groups. In contrast to the antibody responses, proliferative responses to OvMBP20/11 were significantly higher in PI than in INF subjects. Cytokine analysis of peripheral blood mononuclear cell culture supernatants revealed that INF subjects produced significantly more interleukin-10 in response to OvMBP20/11 than did PI subjects. This antigen induced few other cytokines, and there were no differences between study groups.

Soft tissue swelling with fractures: abuse versus nonintentional

The objectives were to 1) define the amount of postfracture swelling at presentation in long bone fractures, and 2) to study the relationship between suspected abuse and/or neglect (A/N) and degree of postfracture swelling at presentation. This was a prospective study of 37 patients less than 11 years of age presenting with long bone fractures to the emergency department (ED) of the Children's Hospital of Michigan between August 1992 and December 1992. Data were recorded at the time of the ED visit and from medical records which were reviewed four to six months later. Of the patients enrolled in the study, eight were categorized as A/N and 29 as nonintentional. There was no difference in reported injury age between the two groups (15.5 +/- 24.5 hours vs 14.0 +/- 17.7, P = 0.8). At presentation the mean increase in circumference from post-fracture swelling was 9.6 +/- 7.1%, using the uninjured extremity as the control. The abuse group had a lesser increase in circumference compared to the nonintentional group, even after adjusting for injury age (3.8 +/- 3.6% vs 11.2 +/- 7.0%, P < 0.006). We concluded that patients with long bone fractures had a mean swelling of 9.6 +/- 7.1% at presentation. Injuries induced by A/N present with less swelling than similar injuries sustained nonintentionally, and we speculate that this difference indicates that the history and/or time of injury may not be reliable.

Gender and estrous cycle effects of the 5-HT1A agonist, 8-OH-DPAT, on hypothalamic serotonin

Effects of the 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 0.04, 0.25, or 1.0 mg/kg), on hypothalamic serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), and their ratio were determined in adult male rats and in diestrous, proestrous, and estrous female rats. Consistent with its action at the somatodendritic 5-HT1A autoreceptor, 8-OH-DPAT decreased the 5-HIAA/5-HT ratio, but the decrease was least evident in proestrous females and in males. Similar to hypothalamic tissue, there was also a decline in the 5-HIAA/5-HT ratio in the hippocampus after treatment with 0.25 mg/kg 8-OH-DPAT. When ovariectomized rats were treated with oil or estradiol benzoate followed 48 h later by oil or progesterone, 0.25 mg/kg 8-OH-DPAT produced a decrease in the hypothalamic 5-HIAA/5-HT ratio in every group except those rats treated with progesterone without estrogen priming. Treatment with estradiol benzoate increased hypothalamic 5-HIAA, and both progesterone and 8-OH-DPAT reduced the metabolite to the level of the ovariectomized control. These results suggest that both estrogen and progesterone contribute to an estrous cycle modulation of the 5-HT1A somatodendritic autoreceptor.

Use of dexamethasone in the outpatient management of acute laryngotracheitis

OBJECTIVE

Recent studies have demonstrated that a single intramuscular injection of dexamethasone (0.6 mg/kg) shortens the duration and severity of illness in hospitalized patients with acute viral laryngotracheitis (croup). Our objective was to determine if dexamethasone has a role in the outpatient management of patients with acute viral croup of moderate severity.

METHODS

Patients, 6 months to 5 years of age, who came to the emergency department (ED) with acute viral croup, a croup score of at least 2 (range 0 to 17), and a disposition of discharge were randomized in a double-blind fashion to receive a single intramuscular injection of dexamethasone, 0.6 mg/kg, or an equal volume of normal saline before discharge from the ED. Patients were excluded if they had any structural abnormalities, had received any steroids in the preceding 24 hours, or if they required beta-agonist therapy, more than one racemic epinephrine treatment, or hospitalization. Patients were followed up by telephone 24 hours and 7 to 10 days after discharge to determine whether additional medical attention was sought for perceived lack of improvement or worsening of symptoms. Secondary outcome included the parents' perception of how the child was doing at 24 hours, based on a 4-point ordinal scale: worse (1), same (2), improved (3), symptoms resolved (4), and the number of days it took for complete recovery.

RESULTS

Of the 38 patients comprising the study group, 19 received dexamethasone. The median age was 19 months (range 6 to 66 months), and median pretreatment croup score was 3 (range 2 to 5) for both groups. The number of patients requiring racemic epinephrine was similar in both groups. Five patients sought additional medical attention within 48 hours. Four of the five patients had received placebo (21% of the placebo group) and one had received dexamethasone (5% of the steroid group) (not statistically significant). At the 24-hour telephone follow-up, significantly more patients in the dexamethasone group had a score consistent with improvement compared with placebo (84% vs 42%, P = .003). There was no difference in the number of days for symptoms to completely resolve between the two groups.

CONCLUSION

The use of dexamethasone in the outpatient management of viral croup was associated with a reduction in severity of illness within 24 hours after treatment. Patients with viral croup of moderate severity should be considered as candidates for the use of dexamethasone before discharge from the ED.

The assessment of handicap: an evaluation of the Environmental Status Scale

The assessment and measurement of disability and handicap are of particular relevance in rehabilitation, as these are the main foci of therapeutic intervention. The area of handicap is the least developed with few measuring tools to provide an objective assessment of status. The Environmental Status Scale (ESS) is now becoming increasingly utilized to measure handicap. It was used in a study of 50 patients on admission and discharge in a neurorehabilitation unit, to analyse its validity and usefulness as an outcome measure of the rehabilitation process. The results suggest it has limited validity, mixes disability and handicap issues and in some sections has a misleading scoring system. It requires modification to overcome these difficulties.