The amphibian peptide Yodha is virucidal for Zika and dengue viruses

Zika virus (ZIKV) has emerged as a serious health threat in the Americas and the Caribbean. ZIKV is transmitted by the bite of an infected mosquito, sexual contact, and blood transfusion. ZIKV can also be transmitted to the developing fetus in utero, in some cases resulting in spontaneous abortion, fetal brain abnormalities, and microcephaly. In adults, ZIKV infection has been correlated with Guillain-Barre syndrome. Despite the public health threat posed by ZIKV, neither a vaccine nor antiviral drugs for use in humans are currently available. We have identified an amphibian host defense peptide, Yodha, which has potent virucidal activity against ZIKV. It acts directly on the virus and destroys Zika virus particles within 5 min of exposure. The Yodha peptide was effective against the Asian, African, and South American Zika virus strains and has the potential to be developed as an antiviral therapeutic in the fight against Zika virus. The peptide was also effective against all four dengue virus serotypes. Thus, Yodha peptide could potentially be developed as a pan-therapeutic for Zika and dengue viruses.

Early AID expression in developing B cells marks a population with a restricted IgH repertoire favoring D-proximal VH gene usage

Activation-induced cytidine deaminase (AID) is well characterized in germinal center reactions as a driver of secondary antibody diversification through the processes of somatic hypermutation and class-switch recombination, but recent reports from clinical and murine studies suggest an additional role during primary diversification. Specifically, inhibition or knockout of AID activity during B cell development results in increased IgM autoantibody production. Furthermore, the expression of AID during development appears to be driven by B cell receptor mediated recognition of autoantigens, including RNA and dsDNA. To examine the pattern of early AID expression, we used lineage tracing in an AID-Cre x R26R-EYFP mouse model to identify a subpopulation of AID experienced (AID-exp) pre-B cells. Sequencing of the IgH repertoire from the AID-exp subpopulation reveals a stark reduction in the diversity of VH gene usage compared to AID-naïve pre-B cells. The reduction in diversity is accompanied by enrichment for specific VH genes, including D-proximal elements associated with B1 cells and autoantibodies. Thus, we discern skewing within the AID-exp repertoire suggestive of antigen-dependent selection in the bone marrow compartment. Our results support the hypothesis that AID is induced in pre-B cells carrying an autoreactive heavy chain and effects tolerization to specific self-antigens.

A synthetic stroma-free germinal center niche for efficient generation of humoral immunity ex vivo

B cells play a major role in the adaptive immune response by producing antigen-specific antibodies against pathogens and imparting immunological memory. Following infection or vaccination, antibody-secreting B cells and memory B cells are generated in specialized regions of lymph nodes and spleens, called germinal centers. Here, we report a fully synthetic ex-vivo system that recapitulates the generation of antigen-specific germinal-center (GC) like B cells using material-surface driven polyvalent signaling. This synthetic germinal center (sGC) reaction was effectively induced using biomaterial-based artificial "follicular T helper cells (T_FH)" that provided both natural CD40-CD40L ligation as well as crosslinking of CD40 and by mimicking artificial "follicular dendritic cells (FDC)" to provide efficient, polyvalent antigen presentation. The artificial sGC reaction resulted in efficient B cell expansion, immunoglobulin (Ig) class switching, and expression of germinal center phenotypes. Antigen presentation during sGC reaction selectively enhanced the antigen-specific B cell population and induced somatic hyper-mutations for potential affinity maturation. The resulting B cell population consisted primarily of GC-like B cells (centrocytes) as well as some plasma-like B cells expressing CD138. With concurrent cell sorting, we successfully created highly enriched populations of antigen-specific B cells. Adoptive transfer of these GC-like B cells into non-irradiated isogeneic or non-lethally irradiated congenic recipient mice showed successful engraftment and survival of the donor cells for the 4 week test period. We show that this material-surface driven sGC reaction can be successfully applied to not only splenic B cells but also B cells isolated from more therapeutically relevant sources such as peripheral blood mononuclear cells (PBMCs), thus making our current work an exciting prospect in the new era of personalized medicine and custom-immunotherapy.

Prospective evaluation of protein C and factor VIII in prediction of cancer-associated thrombosis

Venous thromboembolism (VTE) is a preventable disease, yet it is one of the leading causes of death among patients with cancer. Improving risk stratification mechanisms will allow us to personalize thrombo-prophylaxis strategies. We sought to evaluate Collagen and Thrombin Activated Platelets (COAT-platelets) as well as protein C and factor VIII as biomarkers predictive of cancer-associated thrombosis in a prospective cohort of patients with cancer. Protein C was selected as a candidate based on bioinformatics prediction. Blood samples were collected before chemotherapy. All specimen processing was blinded to clinical data. Surveillance and adjudication of the main outcome of VTE was performed for up to 1 year. We used Cox proportional hazard regression to measure the association of biomarkers and incident events using SAS 9.2 for all statistical analysis. Death was modeled as a competing event. Among 241 patients followed for an average of 10.4 months, 15% died and 13% developed a VTE. COAT-platelets were not predictive of VTE. Low levels of pre-chemotherapy protein C (<118%) (HR 2.5; 95% CI 1.1-5.5) and high baseline factor VIII (>261% I) (HR 3.0; 95% CI 1.1-8.0) were predictive of VTE after adjusting for age, Khorana prediction risk, metastatic disease and D dimer. In addition, low protein C was predictive of overall mortality independent of age, metastatic disease and functional status (HR 2.8; 95% CI 1.3-6.0). Addition of these biomarkers to cancer-VTE risk prediction models may add to risk stratification and patient selection to optimize thrombo-prophylaxis.

Inflammasome proteins in cerebrospinal fluid of brain-injured patients as biomarkers of functional outcome: clinical article

OBJECT

Traumatic brain injury (TBI), the third most common CNS pathology, plagues 5.3 million Americans with permanent TBI-related disabilities. To evaluate injury severity and prognosis, physicians rely on clinical variables. Here, the authors seek objective, biochemical markers reflecting molecular injury mechanisms specific to the CNS as more accurate measurements of injury severity and outcome. One such secondary injury mechanism, the innate immune response, is regulated by the inflammasome, a molecular platform that activates caspase-1 and interleukin-1β.

METHODS

The authors investigated whether inflammasome components were present in the CSF of 23 patients with TBI and whether levels of inflammasome components correlate with outcome. The authors performed an immunoblot analysis of CSF samples from patients who suffered TBI and nontrauma controls and assessed the outcomes 5 months postinjury by using the Glasgow Outcome Scale. Data were analyzed using Mann-Whitney U-tests and linear regression analysis.

RESULTS

Patients with severe or moderate cranial trauma exhibited significantly higher CSF levels of the inflammasome proteins ASC, caspase-1, and NALP-1 than nontrauma controls (p < 0.0001, p = 0.0029, and p = 0.0202, respectively). Expression of each protein correlated significantly with the Glasgow Outcome Scale score at 5 months postinjury (p < 0.05). ASC, caspase-1, and NALP-1 were significantly higher in the CSF of patients with unfavorable outcomes, including death and severe disability (p < 0.0001).

CONCLUSIONS

NALP-1 inflammasome proteins are potential biomarkers to assess TBI severity, outcome, and the secondary injury mechanisms impeding recovery, serving as adjuncts to clinical predictors.

A transcriptional regulator of a pristinamycin resistance gene in Streptomyces coelicolor

Pip is a pristinamycin-induced transcriptional regulator protein detected in many Streptomyces species by its ability to specifically bind sequence motifs within the promoter of a Streptomyces pristinaespiralis multidrug resistance gene (ptr). To investigate the possible role of Pip in regulating multidrug resistance, it was purified from a genetically characterized species, Streptomyces coelicolor, utilizing an affinity matrix of the ptr promoter conjugated to magnetic beads. Reverse genetics identified the corresponding locus and confirmed that it encoded Pip, a protein belonging to the TetR family of procaryotic transcriptional repressors. Pip binding motifs were located upstream of the adjacent gene pep, encoding a major facilitator antiporter homologous to ptr. In vivo analysis of antibiotic susceptibility profiles demonstrated that pep conferred elevated levels of resistance only to pristinamycin I (PI), a streptogramin B antibiotic having clinical importance. Purified recombinant Pip was a dimer (in the presence or absence of PI) and displayed a high affinity for its palindromic binding motifs within the ptr promoter and the upstream region of pep. The Pip/ptr promoter complex was dissociated by PI but not by any of the other nonstreptogramin antibiotics that were described previously as transcriptional inducers. These procaryotic regulatory elements served as the basis for the development of systems allowing repression or induction of cloned genes in mammalian and plant cells in response to streptogramin antibiotics (including pristinamycin, virginiamycin, and Synercid(R)).

Developmental control of stress stimulons in Streptomyces coelicolor revealed by statistical analyses of global gene expression patterns

Stress-induced regulatory networks coordinated with a procaryotic developmental program were revealed by two-dimensional gel analyses of global gene expression. Four developmental stages were identified by their distinctive protein synthesis patterns using principal component analysis. Statistical analyses focused on five stress stimulons (induced by heat, cold, salt, ethanol, or antibiotic shock) and their synthesis during development. Unlike other bacteria, for which various stresses induce expression of similar sets of protein spots, in Streptomyces coelicolor heat, salt, and ethanol stimulons were composed of independent sets of proteins. This suggested independent control by different physiological stress signals and their corresponding regulatory systems. These stress proteins were also under developmental control. Cluster analysis of stress protein synthesis profiles identified 10 different developmental patterns or "synexpression groups." Proteins induced by cold, heat, or salt shock were enriched in three developmental synexpression groups. In addition, certain proteins belonging to the heat and salt shock stimulons were coregulated during development. Thus, stress regulatory systems controlling these stimulons were implicated as integral parts of the developmental program. This correlation suggested that thermal shock and salt shock stress response regulatory systems either allow the cell to adapt to stresses associated with development or directly control the developmental program.

[A decentralized breast cancer screening program in the French department of Bas-Rhin]

Since 1989, in the French department of Bas-Rhin, a breast cancer screening program in going on and its results are presented here. This program, concerning women of 50 to 65 years-old, is decentralized, based on private or public radiologists and the motivation of women because there is no invitation. The interval between screening test is 2 years. After 8 years, the results are rather satisfactory: participation rate of the initial cohort is 77% in December 31st 1997, participation at incident screenings is above than 85%, early indicators (recall rate, detection rate, PPV of screening, PPV of biopsy) are improving with time to attain numbers like international studies. The ADEMAS program shows that a decentralized screening program, based on existing medical structures is possible in France. Anyway, it must be organized, evaluated at any time, with a quality assurance system to guarantee the women the best taking charge.

Crystal engineering: a case study using the 24 kDa fragment of the DNA gyrase B subunit from Escherichia coli

Site-directed mutagenesis was used to determine the efficacy of changing surface residues to improve crystal quality. Nine mutants of the 24 kDa fragment of the Escherichia coli DNA gyrase B subunit were produced, changing residues on the protein's surface. The mutations changed either the charge or the polarity of the wild-type amino acid. It was found that single amino-acid changes on the surface could have a dramatic effect on the crystallization properties of the protein and generally resulted in an improvement in the number of crystal-screen hits as well as an improvement in crystal quality. It is concluded that crystal engineering is a valuable tool for protein crystallography.

Urinary creatinine adjusted reference ranges for homovanillic and vanillylmandelic acid in children and adults

The relationship between urinary homovanillic acid (HVA), vanillylmandelic acid (VMA) and creatinine is investigated and reference ranges are constructed for HVA and VMA. A total of 769 urine samples were obtained from children and adults. The ratios HVA/creatinine and VMA/creatinine were highly correlated with creatinine concentration; hence, reference to creatinine was found to be an inappropriate adjustment for urinary dilution. An alternative method based upon linear regression is proposed. After allowing for differing levels of creatinine, HVA and VMA were found to be significantly correlated with age, height and weight for individuals aged less than 20 years. In those aged over 20 years, HVA was significantly correlated with weight and VMA with age. Differences between sexes were found in the levels of HVA and VMA, the exception being VMA in the over 20 age group. Reference ranges were constructed for HVA and VMA which are variously dependent upon creatinine, age, sex and weight.

Quality control in mammography: an initiative in France

The ultimate effectiveness of any mass screening campaign is directly related to strict compliance with certain rules and technical protocols designed for radiological installations. Concerning radiological screening, the primary technical objective is to ensure reproducibly high quality images at low radiation dose to the patient. This paper describes the methodology followed for the implementation of a quality control (QC) programme of 48 mammography installations used within the context of the breast cancer screening campaign in the Bas-Rhin region of eastern France. In order to demonstrate the efficacy of such a programme, results of QC tests and procedures relating to each element of the radiological imaging chain are presented and compared for four control visits carried out at 6 month intervals over a period of 2 years. A reduction of 50% (from 16 mGy to 7.5 mGy) of breast entrance doses (normalized to a breast thickness of 4.5 cm) and a significant improvement of detectability of high contrast details are discussed. The importance of encouraging an extension of a similar process to the other screening experiments currently underway in France is emphasized.

False positive results in a neuroblastoma screening programme

Twenty thousand, eight hundred and twenty-nine babies were screened for neuroblastoma at 6 months of age by measuring homovanillic (HVA) and vanillylmandelic (VMA) acid in urine and rationing these to creatinine. Using a "cut off" of the mean + 3 SD, 10 were found to be positive. Two were found on evaluation to have neuroblastoma and in the remaining 8 the raised levels of HVA and/or VMA returned to normal. Only one of the 8 false positive babies was absolutely normal, most having a chronic disorder or illness. Utilising new centiles which relate HVA and VMA to creatinine, only 3 of the 8 would have remained positive, a false positive rate of 0.01%. The false negative rate would have remained unchanged.

Creatinine related reference ranges for urinary homovanillic acid and vanillylmandelic acid at 6 months of age

The relationship between homovanillic acid (HVA), vanillylmandelic acid (VMA), and creatinine in the urine of 6 month old babies has been studied and reference ranges in the form of centiles constructed for HVA and VMA against creatinine. Over 10,000 urine samples were collected from babies in four health districts in the north of England. HVA and VMA concentration, either independently or when divided by creatinine concentration, were dependent upon the absolute concentration of creatinine in the sample. After adjustment for creatinine significant differences in the mean concentration of HVA were found between sexes. No such differences were found for VMA. HVA and VMA were also found to be age dependent. Centiles were constructed using a procedure which makes no distributional assumptions about the data. The net effect of utilising these centiles was to increase the predictive value of a positive screening test from 20% to 40% without any increase in the false negative rate.

Screening for neuroblastoma in the north of England

OBJECTIVE

To determine the feasibility of establishing a system of screening for neuroblastoma.

DESIGN

Prospective study of mass screening in four clearly defined geographical areas.

SETTING

Four health districts of the Northern region of England.

SUBJECTS

20,829 babies aged 6 months, 92% of target population.

INTERVENTIONS

Collection of urine on filter paper for analysis of content of homovanillic and vanillylmandelic acid in relation to urinary creatinine concentrations.

MAIN OUTCOME MEASURES

Derivation of reference range. Identification of babies with homovanillic or vanillylmandelic acid > 3 SD above the mean (positive cases). Investigation of positive cases for evidence of neuroblastoma.

RESULTS

The upper limit of normal (3 SD above the mean) for vanillylmandelic acid was 15 mumol/mmol creatinine and for homovanillic acid 24 mumol/mmol creatinine. Of the 20,829 babies screened, 2537 (12.2%) required a second sample to be taken because the first sample was inadequate. Of these, 527 (2.5%) provided a liquid urine specimen and 10 (0.04%) had positive results for neuroblastoma. Two of them had neuroblastoma (true positives) and eight did not (false positives). A further three children from the cohort were subsequently found to have neuroblastoma; they had raised homovanillic acid or vanillylmandelic acid values, or both, but screened negative at 6 months.

CONCLUSIONS

Screening for neuroblastoma is possible in the health care system of the United Kingdom. Evaluation of the efficacy of screening in reducing the mortality from neuroblastoma requires a controlled trial.

A pilot study of screening for neuroblastoma in the north of England

A pilot study has been carried out to assess the feasibility of screening for neuroblastoma in 6-month-old infants in the north of England. A total of 20,829 infants were screened. Two true-positive cases were found, along with eight false-positive and three false-negative cases. It was shown that the concentrations of catecholamine metabolites in the urine are dependent on the creatinine content; centiles have been established to allow this relationship to be taken into account. Five of the eight false-positive cases would have been correctly assessed as normal if the new centiles had been used. Preliminary results lend support to the need for a well-designed study of neuroblastoma screening to be carried out, with death from this disease as the only end point.

[Principles and first results of the European program of breast cancer screening in the Bas-Rhin]

A mammographic breast cancer screening began in May 1989 in the Bas-Rhin. It has been selected by "Europe against Cancer" for France. Its aim is not to prove the efficiency of mammography screening by one view every two years, as many studies has proven it. Its purpose is to find the best methodological model for a national campaign. Its principles are to change attitudes and to obtain the active participation of the physicians without creating new structures. This campaign is offered to women aged 50 to 65, living in Bas-Rhin (74,200 women) without individual convocations. Their participation is obtained by a continuous information and motivation. The mammographic examinations are taken in charge by the Health Insurance and performed by the radiologists who have signed a convention. The homogeneity of the results is assured by a double and triple reading under the responsibility of the ADEMAS. In May 1990, after one year, 17,228 women had presented to the screening test. The positive test rate is 7.6% and 7.6% of the women had a diagnostic procedure which indicated a biopsy for 188 women. Among the first 176 histological results, 76 cancers have been diagnosed, 100 women had a benign lesion. The ratio cancer/benign lesion is 0.76.

A simple technique for head repositioning in CT scanning

With conventional CT scans, alterations of morphology on repeated examinations can only be appreciated if significant, because identical slice positions are impossible to achieve. The authors have developed a simple and accurate method of repositioning the head not requiring conventional stereotactic head fixation and suitable for the outpatient situation.

Outcome in mild and moderate cervical dysplasias related to the presence of specific human papillomavirus types

In situ hybridization with biotinylated DNA viral probes (ISH-B) for human papillomavirus (HPV) types 6/11, 16, 18, 31, and 33 was used to study the outcome in 32 cases of mild and 21 cases of moderate cervical dysplasia with koilocytotic change that were followed for an average of 27 mo. The rates of regression, persistence, and progression for cervical intraepithelial neoplasia (CIN) I and CIN II were 50%, 41%, and 9%, and 43%, 48%, and 9%, respectively. While progression of HPV 16 CIN I and II lesions was observed, regression occurred in 80% (four of five) and 43% (three of seven) of CIN I and II HPV 16-positive lesions, respectively. Regression was also seen in lesions that contained HPV 31 or HPV 33. All of the HPV 18 lesions persisted. The findings are compared with those of previous studies. Since some of the assumed more aggressive viral types can regress when followed by cytologic and biopsy examinations, caution must be exercised when attempting to predict the clinical outcome based solely on the specific viral type present in a given CIN lesion.

Strychnine poisoning as an unusual cause of convulsions

A fatal case of strychnine poisoning is presented. The patient vomited then suffered a series of tonic convulsions which were triggered by tactile stimulation. In between paroxysms he was initially alert. Eventually the patient became comatosed due to anoxia and had a cardiac arrest. He presented with a marked metabolic acidosis and rapidly developed renal failure caused by acute rhabdomyolysis. This clinical picture is classical for strychnine poisoning and the complications which the intoxication produces. Attention is drawn to the fact that survival can even follow the ingestion of very large doses of strychnine providing there is no delay in diagnosis and treatment.

Familial lysinuric protein intolerance presenting as coma in two adult siblings

Lysinuric protein intolerance (LPI) is an inborn error of metabolism which usually presents in infancy with failure to thrive and vomiting. Two patients are described who presented in adult life with hyperammonaemic coma due to LPI. Both had been underweight and had had intermittent gastrointestinal symptoms during childhood. They were of normal intellect and had maintained good health, until presentation in their thirties, by unconscious dietary protein avoidance. The diagnosis of LPI should be considered in patients who present with obscure relapsing coma associated with hyperammonaemia. Considerable clinical improvement may result from dietary protein restriction and citrulline supplementation.

Detection and localization of human papillomavirus in penile condylomas and squamous cell carcinomas using in situ hybridization with biotinylated DNA viral probes

Human papillomavirus (HPV) has been previously demonstrated in male genital neoplasms using Southern blot hybridization (SBH) and in situ hybridization with radiolabeled probes (ISH-R). In this study we used in situ hybridization with biotinylated DNA viral probes (ISH-B), a technique that can be applied to routinely collected and processed tissue. Thirty cases of exophytic penile condyloma acuminatum and nine cases of invasive squamous cell carcinoma of the penis were examined for the presence of HPV using ISH-B for HPV types 6, 11, 16, 18, 31, and 33. HPV DNA was found in 25 of 30 (83%) penile condylomas; HPV type 6 in 13 (43%); and HPV type 11 in 12 (40%). Slight cross-reactivity between HPV types 6 and 11 was noted. None of the condyloma cases was positive for HPV types 16, 18, 31, or 33. One of the nine patients with squamous cell carcinoma of the penis was positive for HPV 16. In situ hybridization with biotinylated DNA viral probes is a highly sensitive method for detecting and localizing HPV in penile condylomas. This method, however, may not be as sensitive as SBH for detecting HPV in invasive penile squamous cell carcinomas.

Biochemical screening for neuroblastoma in infants: a feasibility study

Neuroblastoma is the most common solid tumour of childhood with an incidence of about 1:10,000 births. Prognosis depends on age and stage at presentation and for disseminated disease presenting after the age of 1 year has scarcely altered at all in the past 20 years. In Japan a method has been pioneered of mass population screening of 6-month-old babies using a urine test for the catecholamine metabolites vanillylmandelic acid and homovanillic acid. They have been able to detect the majority of cases at 6 months and have improved the overall prognosis from 25% to 75% survival. A pilot study to assess the feasibility of such a study in the UK has been carried out in the north of England. Methodology has been established for the collection of urine by health visitors and biochemical analysis by gas chromatography with both flame ionisation and mass spectrometry detection; 4,897 samples have been collected, and reference ranges have been established.

Incidence and types of acute viral hepatitis in Newcastle upon Tyne

The incidence and types of viral hepatitis in the city of Newcastle upon Tyne have been studied by serological analysis of (a) all blood samples sent to the virological laboratory for hepatitis testing and (b) all blood samples sent by general practitioners to the biochemical laboratory for liver function testing. The annual detection rate of acute viral hepatitis was found to be 31.5 cases/100,000 population, of which 9.1 were hepatitis B. Only three sporadic cases of non-A non-B hepatitis were identified. The incidence of hepatitis is at least four-fold greater than suggested by notification rates and may be substantially higher as general practitioners rarely requested laboratory confirmation of household contacts of index cases.

Biotinidase deficiency: a survey of 10 cases

Ten patients with biotinidase deficiency were studied. Clinical findings at presentation varied with dermatological signs (dermatitis and alopecia), neurological abnormalities (fits, hypotonia, and ataxia), and recurrent infections being the most common features, although none of these occurred in every case. Biochemically the disease is characterised by metabolic acidosis and organic aciduria. Treatment with biotin results in pronounced, rapid, clinical and biochemical improvement, but some patients have residual neurological damage comprising neurosensory hearing loss, visual pathway defects, ataxia, and mental retardation. The cause of this permanent damage remains obscure and it is not clear if the early introduction of treatment will prevent it.

Urinary excretion of HMMA and HVA in infants

Gas chromatography with flame ionisation detection has been used to establish the normal urinary excretion values of homovanillic acid and 4-hydroxy-3-methoxymandelic acid in 808 infants aged 6 months. This study, the essential pre-requisite for population screening for neuroblastoma in babies, reveals a mean homovanillic acid of 10.9 mumol/mmol creatinine and mean 4-hydroxy-3-methoxymandelic of 6.8 mumol/mmol creatinine. The upper 95% confidence interval were 25.5 mumol/mmol creatinine for homovanillic acid and 15.0 mumol/mmol creatinine for 4-hydroxy-3-methoxymandelic. Gas chromatography/mass spectrometry analysis of the 39 samples, (4.8%) with apparent increased excretion of one or both metabolites, revealed that this was, in each case, due to interfering peaks on chromatography.

The characterisation of molecular forms of acetylcholinesterase in Hirschsprung's disease

Aganglionic rectal tissue from patients with Hirschsprung's disease contains four forms of acetylcholinesterase; the major component has a sedimentation coefficient in the region of 10.0S. Results from gel filtration confirm these findings and, when used in conjunction with the sedimentation data, allow the determination of the molecular mass of these forms. The four species of acetylcholinesterase include: monomer, G1, 74 kDa dimer, G2, 131 kDa; tetramer G4, 275 kDa and an asymmetric form, A12, 811 kDa. Evidence is provided which shows that the major form, G4 interacts with the detergent Triton X-100. Selective measurement of G4-AChE using a suitable assay may provide the basis for improving the existing means of diagnosis of Hirschsprung's disease.

Neural tube defect-specific acetylcholinesterase: its properties and quantitation in the detection of anencephaly and spina bifida

Amniotic fluid from neural tube defect-affected pregnancies (NTD) contains three forms of acetylcholinesterase (AChE), the major species of which is present only in trace amounts in normal pregnancies or those associated with a non-NTD fetal malformation. The activity of this 'specific' AChE is increased 62-fold in the presence of NTD and its measurement provides a sensitive and specific test for the biochemical detection of this disorder. The sedimentation coefficient of 'NTD specific' AChE (10.3S) indicates that it is a tetrameric species, and that the two additional forms present, (4.0S and 5.5S) are monomer and dimer, respectively. Gel filtration studies also support these findings. Combining these data, the molecular masses of monomer, dimer and tetramer are shown to be 78, 126 and 256 kDa (+/- 10%). 'NTD-Specific' AChE does not react with the detergent Triton X-100, indicating that it is a soluble, and probably secreted, species without membrane associating properties.

A 7-year study of the diagnostic value of rectal mucosal acetylcholinesterase measurement in Hirschsprung's disease

Over a 7-year period, 213 children were investigated for failure to pass meconium or for chronic constipation. Of these, 45 were confirmed to have Hirschsprung's disease; in this group the acetylcholinesterase activity in rectal biopsy tissue was significantly increased (P less than .001; mean 34.2, 95% confidence limits, 8.6 to 95.2) units g-1 when compared with the non-Hirschsprung's group (mean 6.6, 95% confidence limits, 2.0 to 15.9 units g-1). By expressing the acetylcholinesterase activity as a percentage of the total cholinesterase activity it is possible to compensate for evaporative weight loss and the combination of these two measurements improves the overall diagnostic value of the test. There were no false-positive and only two false-negative results.

Profound hypophosphataemia in patients collapsing after a "fun run"

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Molecular forms of acetylcholinesterase in Hirschsprung's disease

We describe changes in the levels of different molecular forms of acetylcholinesterase in four cases of Hirschsprung's disease linked to the transition from aganglionic to normal bowel. In addition changes in a control case with histologically normal bowel is reported. In all patients with Hirschsprung's disease there is a marked increase in the level of the tetrameric form of the enzyme in the aganglionic region. The changing level of this form of the enzyme correlates well with the histochemical appearance suggesting that quantitative measurement of this molecular species might form the basis of an improved diagnostic test for the disease.