Phenotype/Genotype Correlations in the Ultrastructure of Monogenetic Glomerular Diseases

Electron microscopy defined classic patterns of hereditary glomerular disease long before genetics revealed an underlying specific mutation. Genetic analysis is now easier to perform in clinical practice but an earlier optimism that genetics would predict disease severity and phenotype is challenged. The classic paradigm is Alport nephritis in which only a subset of mutations may predict glomerular abnormalities and disease severity. Interpretation of ultrastructural pathology of monogenetic diseases like Alport nephritis is complicated when the proband is the first family member to be diagnosed or there is discrepancy between clinical presentation and ultrastructural changes. In this review the authors have selected a dozen cases representative of common monogenetic glomerular diseases as a platform to discuss the utility of diagnostic electron microscopy in the era of molecular genetics. The emphasis is on genotype/glomerular phenotype correlations.

Contribution of neural crest-derived cells in the embryonic and adult thymus

Neural crest (NC)-derived mesenchyme has previously been shown to play an important role in the development of fetal thymus. Using Wnt1-Cre and Sox10-Cre mice crossed to Rosa26(eYfp) reporter mice, we have revealed NC-derived mesenchymal cells in the adult murine thymus. We report that NC-derived cells infiltrate the thymus before day 13.5 of embryonic development (E13.5) and differentiate into cells with characteristics of smooth muscle cells associated with large vessels, and pericytes associated with capillaries. In the adult organ at 3 mo of age, these NC-derived perivascular cells continue to be associated with the vasculature, providing structural support to the blood vessels and possibly regulating endothelial cell function.

Phenotypic spectrum of neurodegeneration associated with mutations in the PLA2G6 gene (PLAN)

BACKGROUND

Neurodegeneration associated with brain iron accumulation (NBIA) comprises a heterogeneous group of disorders in which disruption of cellular mechanisms leads to accumulation of iron in the basal ganglia. This group includes patients with recently discovered mutations in the PLA2G6 gene encoding a calcium-independent phospholipase A2 enzyme that catalyzes the hydrolysis of glycerophospholipids. Previously, children with PLA2G6 mutations have been diagnosed with several different disorders and we wished to better define the phenotype of PLA2G6- associated neurodegeneration.

METHODS

Detailed review of the clinical and genetic features of 14 and radiologic features of 13 of these patients with PLA2G6 mutations was undertaken.

RESULTS

Median age of symptom presentation was 14 months. One third of the cohort presented following an intercurrent illness. The children had progressive cognitive and motor skill regression, with evidence of axial hypotonia, four limb spasticity, bulbar dysfunction, and strabismus. All patients developed cerebellar ataxia and dystonia. Most patients had optic atrophy. Brain imaging demonstrated cerebellar cortical atrophy and gliosis in all patients. Changes consistent with increased iron deposition were identified in the globus pallidus and substantia nigra. Novel corpus callosum changes are also reported.

CONCLUSION

We describe a cohort of patients with PLA2G6-associated neurodegeneration (PLAN). Although patients with PLAN have previously been diagnosed with infantile neuroaxonal dystrophy, neurodegeneration associated with brain iron accumulation, and Karak syndrome, they display a characteristic clinical and radiologic phenotype. PLA2G6 mutational analysis will negate the need for more invasive diagnostic procedures such as tissue biopsy.

Evaluation of the impact of errors in the measurement of backfat depth on the prediction of fat-free lean mass

The development of regression equations to predict carcass composition typically assumes that the independent variables, such as backfat depth, are measured without error. However, technological and operator-specific types of measurement errors do exist. To evaluate the impact of measurement error for backfat depth, Monte Carlo simulation was used to model carcass fat-free lean mass (FFLM) in pigs. In the simulation, FFLM was a linear function of carcass weight and actual backfat depth (ABFD). Carcass weight was assumed to be measured without error, but measurement errors were generated such that the correlation (r(BF)) of the measured backfat depth (BFD) and ABFD ranged from 0.70 to 0.95. Two types of measurement errors were simulated: 1) constant variation that was additive to the variance of ABFD, and 2) variation proportional to the ABFD that was additive to the variance in ABFD. A total of 1,000 replications of 1,000 pigs were simulated. Within each type of measurement error, the absolute values of the regression coefficients and R2 values of the equations decreased as r(BF) decreased. The probability of the backfat depth squared (BFD2) being significant (P < 0.05) in the regression equation was increased when the measurement errors were proportional to ABFD. The occurrence of a significant BFD2 variable was 792 times out of 1,000 replications when r(BF) = 0.95 and increased to 996 times out of 1,000 when r(BF) = 0.85 for BFD with type 2 measurement errors. The inclusion of a CW x BFD variable in the regression equations (P < 0.05) increased (270 to 423 times out of 1,000) as r(BF) decreased from 0.85 to 0.70 for BFD with type 2 errors. Equations developed from BFD with measurement errors resulted in biased predictions of FFLM and changes in FFLM per unit change in BFD. The level and type of measurement errors that exist in the independent variables should be evaluated.

Substance P and acetylcholine are co-localized in the pathway mediating mucociliary activity in Rana pipiens

Mucociliary activity is an important clearance mechanism in the respiratory system of air breathing vertebrates. Substance P (SP) and acetylcholine play a key role in the stimulation of the mucociliary transport in the frog palate. In this study, retrograde neuronal tracing was combined with immunocytochemistry for SP and choline acetyl transferase (ChAT) in the trigeminal ganglion and for neurokinin-1 receptor (NK1R) in the palate of Rana pipiens. The cells of origin of the palatine nerve were identified in the trigeminal ganglion using the retrograde tracer Fluorogold (FG). Optimal labeling of FG cells in the trigeminal ganglion was obtained at 96 h of exposure. Immunoflorescent shows that SP and acetylcholine are co-localized in 92% of the cells labeled with FG in the trigeminal ganglion. NK1 receptors were found in the membrane of epithelial and goblet cells of the palate. Ultrastructural study of the palate showed axonal-like endings with vesicles in connection with epithelial and goblet cells. These results further support the concerted action of both neurotransmitters in the regulation of mucociliary activity in the frog palate.

The metabolic syndrome and schizophrenia: the latest evidence and nursing guidelines for management

The introduction of second-generation antipsychotic drugs for the treatment of schizophrenia has provided significant benefits for clients experiencing this disorder. While they have been found effective in reducing psychotic symptoms, there is evidence that these drugs are also linked with a group of side effects commonly known as the metabolic syndrome. Mental health nurses are well positioned to prevent, detect and/or manage the development of this problematic constellation of symptoms. Guidelines for practice can be useful in prevention and management of the syndrome and enhance nursing care of clients who are taking second-generation antipsychotics.

Gene therapy progress and prospects: Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disorder affecting 1/3500 male births. There is currently no effective treatment, but gene therapy approaches are offering viable avenues for treatment development. The last 10 years have seen the development of a number of strategies and tools for muscle gene therapy. However, the major hurdle has been the inability to deliver vectors at high enough efficiency via a systemic route. The last 2-3 years (reviewed here) have seen unrivalled progress in efficient systemic delivery of viral and non-viral gene transfer agents and antisense oligonucleotides. This progress, coupled with the successful completion of the first gene therapy clinical trial for DMD, has led to three more clinical trials planned for the immediate future.

Clinical assessment and core outcome variables are poor predictors of hip arthritis diagnosed by MRI in juvenile idiopathic arthritis

OBJECTIVES

To compare the diagnostic performance of clinical assessment against magnetic resonance imaging (MRI) diagnosed hip arthritis in a juvenile idiopathic arthritis (JIA) population. To determine the clinical and serological predictors of MRI diagnosed hip arthritis.

METHODS

A total of 34 JIA patients with established disease (mean disease duration 6.3 yrs) had their hip MRIs scored for features of active hip arthritis and hip damage. Results were compared with clinical variables (disease subtype, history of hip pain, core outcome variables (COV)) and the clinician's assessment of active hip arthritis.

RESULTS

MRI features of active hip arthritis were found in 45 hips (70%) and hip damage in 36 hips (56%). Clinical assessment had fair agreement with MRI scoring of active arthritis in patients with disease duration <4 yrs (kappa score 0.38, P = 0.045). Clinical assessment had a sensitivity of 25.7% and specificity of 91% for detecting MRI diagnosed arthritis. Of the core outcome variables only erythrocyte sedimentation rate predicted inflammation detected on MRI (r = 0.44, P = 0.014).

CONCLUSIONS

The association between the clinician's assessment, core outcome variables and MRI findings in this study was limited. This indicates that clinical and laboratory findings are inadequate diagnostic tools for the assessment of hip arthritis when compared with MRI as the gold standard.

Adaptation of healthy mastication to factors pertaining to the individual or to the food

Mastication is a physiological process controlled by the central nervous system and modulated by inputs from the mouth. Both the intrinsic characteristics of the subject and the extrinsic characteristics of the chewed food are responsible for variations of the masticatory function. Age, gender and dental state constitute the most studied intrinsic factors whereas hardness, rheological characteristics such as plasticity or elasticity, and food size are the better known extrinsic factors. These factors cause physiological adaptations which can occur during individual cycles or the whole sequence of mastication. Electromyographic and jaw movements (kinematic) recordings are commonly used to study mastication, from which, several variables can be measured. Vertical and lateral amplitudes and, velocities of jaw movements, are only given by kinematic recordings. Bioelectrical activities per cycle or per sequence are closely linked to masticatory forces and are measured from electromyographic recordings. Number of cycles, sequence duration and masticatory frequency can be measured from both types of recordings. The objective of this review is to provide an overview of the variations of the measured masticatory variables that occur when mastication adapts to changes in characteristics of the individual or the food.

Antipsychotic drugs and pregnant or breastfeeding women: the issues for mental health nurses

Antipsychotic drugs and pregnant or breastfeeding women: the issues for mental health nurses Mental illness can affect up to 10% of pregnant women, and women with a pre-existing psychiatric condition are more likely to experience a relapse of symptoms during pregnancy. Antipsychotic drugs are an important part of the treatment of psychotic illnesses; however, their safety with pregnant or breastfeeding women has not been fully established. Given that these drugs will be ordered for pregnant or breastfeeding women diagnosed with a psychosis or with a pre-existing psychiatric condition, it is imperative that mental health nurses and others administering the drugs, or caring for those taking the drugs, be aware of their consequences. A review of the available evidence, albeit at times contradictory, is presented along with a discussion of the implications for mental health nurses. Recommendations for consideration when administering or counselling women regarding the use of antipsychotic drugs in pregnancy or when breastfeeding, are also included.

Guidelines and adenosine dosing in supraventricular tachycardia

This retrospective review of present practice of administration of adenosine by paediatricians shows that current guidelines recommend starting doses that are effective in only 9% of infants and children.

Anosmia is very common in the Lewy body variant of Alzheimer's disease

BACKGROUND

Olfactory abnormalities are reported in Alzheimer's disease and Parkinson's disease. Anosmia appears to be common in dementia with Lewy bodies but not in pure Alzheimer's disease.

OBJECTIVE

To determine whether anosmia improves discrimination between the Lewy body variant (LBV) of Alzheimer's disease and "pure" Alzheimer's disease.

METHODS

106 cases of necropsy confirmed pure Alzheimer's disease (n = 89) or LBV (n = 17) were reviewed. All had received butanol odour threshold testing. Anosmia was defined as a score < or = 1.0 on a 0-9 point scale. Logistic regression analysis was used to model potential predictors (for example, parkinsonism, smoking, hallucinations) of neuropathological diagnosis and anosmia.

RESULTS

LBV cases had an increased prevalence of anosmia (65%) compared with Alzheimer's disease (23%; odds ratio (OR) = 6.3, p = 0.00045), or normal elderly people (6.7%). Within the dementia cases, the negative predictive value (92%) and specificity (78%) of anosmia were both good; sensitivity for detecting LBV was 65%, but the positive predictive value (PPV) was only 35%. Logistic regression models showed anosmia (OR = 5.4, p = 0.005) and visual hallucinations (OR = 7.3, p = 0.007) were strong independent predictors of Lewy body pathology. When anosmia was added as a core feature to consensus diagnostic criteria for probable Lewy body dementia, five additional cases of LBV were detected (29% increased sensitivity), but with four additional false positives (1% increased discrimination, 4% decreased specificity, 33% decreased PPV).

CONCLUSIONS

Anosmia is very common in LBV. Adding anosmia as a core feature improved sensitivity for detecting LBV, but did not improve discrimination between Alzheimer's disease and LBV owing to a concomitant increase in false positives.

Clostridium difficile: a questionnaire survey of laboratory practice in England, Wales, and Northern Ireland

Since January 2004, the incidence of Clostridium difficile associated disease (CDAD) has been monitored by a systematic, national, laboratory surveillance system. This system incorporates the recommendations of a body of experts, the National Clostridium difficile Standards Group, which was convened in 2002 to advise the Department of Health (DoH). The recommendations of the group were informed by a questionnaire survey of current practice, and the results of that survey have been used to assess the implications of the recommendations on laboratory practice. Large variability was found as to the specimens selected, tested, and reported on for C. difficile. Standardisation of the diagnosis and reporting of CDAD is desirable and necessary to increase understanding of its epidemiology.

MRI of the marrow in the paediatric skeleton

Magnetic resonance imaging (MRI) has greatly advanced evaluation of marrow diseases of the paediatric skeleton. As with many other aspects of paediatric radiology it is important to recognize the normal variations in the appearance of the marrow that occur in the growing child. These normal variations need to be differentiated from diseases and conditions that affect the marrow. This review describes the normal changes that occur in children with age, and the appearances of the pathological changes seen in infection, infiltration, haematological disorders, transplantation and radiation therapy.

The circumstances of adults with a psychotic disorder

This article presents some findings about adults with a psychotic disorder who were identified in the OPCS surveys of psychiatric morbidity. The main aim of the analysis was to identify characteristics associated with differences in the circumstances and health-related behaviour of adults aged 16-64 with psychosis. The analysis covers people who were identified by the various criteria used on the surveys as having a psychotic illness and who were considered to be living in private households. First we describe briefly the survey methods used and how diagnoses of psychosis were derived. We then present results from four topic areas covered in the analysis. These are: use of medication, use of health services, difficulties with activities of daily living, and social support.