Hypertrophic cardiomyopathy: histopathological features of sudden death in cardiac troponin T disease.

BACKGROUND: Patients with hypertrophic cardiomyopathy (HCM) are at increased risk of premature death; this is particularly apparent for patients with mutations of the troponin T gene. Myocyte disarray and interstitial fibrosis, pathological features of HCM, may be determinants in these deaths. The relation between genotype, pathological phenotype, and mode of death has not been explored. METHODS AND RESULTS: Seventy-five hearts with HCM were examined. DNA was available in 50 for screening of the troponin T gene. The macroscopic findings, percentage of disarray, percentage of fibrosis, and percentage of small-vessel disease were correlated with the genotype. A troponin T mutation was identified in 9 of the 50 patients, 8 of whom died suddenly. Patients with a troponin T mutation were younger (mean age, 21.0 years [range, 6 to 37] versus 39.1 years [range, 14 to 72]; P<0.0001), had more sudden death (P=0.02), and had lower heart weights, less fibrosis, and greater disarray than other HCM patients (mean heart weight, 380.3+/-105.4 versus 585.0+/-245.7 g, P=0.002; mean fibrosis, 0.7+/-0.4% versus 2.6+/-2.8%, P=0.001; mean disarray, 46.2+/-7.2% versus 24.1+/-15.9%, P<0.0001; and mean small-vessel disease, 11.7+/-14.6 versus 14.1+/-8.7, P=0.6, respectively). Similarly, patients with troponin T mutations who died suddenly had lower heart weights and greater disarray than patients who died suddenly with unknown genotype (ie, troponin T mutation excluded) (mean heart weight, 429.8+/-75.4 versus 559.6+/-204.43 g, P=0.04, and mean disarray, 40.1+/-9.4% versus 20.2+/-12.6%, P=0.002, respectively). CONCLUSIONS: Patients with troponin T mutations had severe disarray, with only mild hypertrophy and fibrosis. These patients died suddenly and at an especially early age. We propose that extensive myocyte disarray in the absence of marked hypertrophy is the pathological substrate for sudden death in these patients.

Expression of CD44 during early development of the chick embryo.

CD44, the major cell-surface receptor for hyaluronate, is expressed on many cell types to mediate different functions including cell activation, homing and adhesion. The early pattern of CD44 expression was determined in the avian embryo by using a specific monoclonal antibody in whole-mount and tissue sections. CD44 was first expressed on cephalic neural fold cells and later on by subpopulations of pre-and migratory cranial neural crest cells. Trunk neural crest cells did not express CD44. At the 18-20 somite stage, CD44 expressing cells were also localized in the caudal region of the embryo, in the mesoderm of the remaining primitive streak and in the caudal ectoderm and above the secondary neural tube during the process of cavitation. In addition, some hemopoietic cells present in the blood stream were also CD44 positive.

Molecular motors in the heart.

The contractile apparatus of muscle is a highly efficient and adaptable mechanism for producing movement and is exploited throughout the animal kingdom. Molecular biology is yielding important insights into the intricate functioning of muscular contraction, especially in the heart, and in explaining the genesis of inherited myopathies. Mutational analyses of the sarcomeric-protein genes in conjunction with clinical assessment have shown that certain mutations indicate a more serious prognosis in HCM. Detecting these mutations in individuals is important for screening other family members for the disease. Understanding the contractile apparatus at the molecular level could contribute to the design of more effective drugs for treatment of cardiac diseases.

A new mutation of the cardiac troponin T gene causing familial hypertrophic cardiomyopathy without left ventricular hypertrophy.

AIM: To screen for a mutation of the cardiac troponin T gene in two families where there had been sudden deaths without an increase in left ventricular mass but with myocardial disarray suggesting hypertrophic cardiomyopathy. METHODS: DNA from affected individuals from both families was used to screen the cardiac troponin T gene on an exon by exon basis. Mutation screening was achieved by polymerase chain reaction and direct sequencing. Where appropriate, a mutation was confirmed by restriction digest. RESULTS: A novel missense mutation of exon 9 was found in the affected individuals of one of the families. This mutation at amino acid 94 resulted in the substitution of arginine for leucine and was not found in 100 normal control samples. A mutation of the cardiac troponin T gene was excluded in the second family. CONCLUSIONS: A mutation of the gene for the sarcomeric protein cardiac troponin T can cause familial hypertrophic cardiomyopathy with marked myocyte disarray and frequent premature sudden death in the absence of myocardial hypertrophy at clinical or macroscopic level.

Quantification of Marek's disease virus in chicken lymphocytes using the polymerase chain reaction with fluorescence detection.

A quantitative assay was developed for Marek's disease virus (MDV). The assay determines the numbers of viral genomes present in samples by polymerase chain reaction (PCR) amplification of a portion of the viral genome for a restricted number of cycles. Fluorescent-tagged primers are used for the PCR amplification which allows quantification of the fluorescent product. Previously, quantitation of Marek's disease virus has required plaque assays, which are laborious and potentially error-prone, and this had limited quantitative comparisons. The PCR assay is rapid, less laborious and can be applied to high levels of accuracy, since replicate assays can be carried out relatively easily. The PCR-based assay assesses the number of viral genomes present in the sample, rather than the numbers of infected cells measured in the plaque assay, however correlation between the two assays is high, suggesting viral copy number per cell may be rather uniform. In crosses between genetically resistant and susceptible animals the PCR-based assay was correlated significantly with subsequent development of disease, and was a better predictor than the plaque assay of the likelihood of development of pathological disease in the birds studied.

A follow-up study of children attending a primary-age language unit.

Twenty-seven children of normal non-verbal intelligence and a mean age of 8 years, attending a primary-age language unit, were assessed on measures of language, reading and behavioural adjustment. Three and a half years later, when many of the children had reached secondary school age, they were re-assessed using the same measures. Although mean language and reading age scores had improved, they were still well below age level and the gap between chronological age and language and reading ages had increased. There was also some evidence of increasing behavioural and emotional problems. Children who had moved to mainstream education at follow-up had, on average, higher levels of intelligence and significantly higher scores on language and reading tests than the children who had remained in special education. However, even amongst this group many problems persisted, although few pupils received any additional help in dealing with them.

Spontaneous epileptiform seizures but increased resistance to kindled seizures in a mutant Sprague-Dawley rat (mf/mf).

Approximately 30% of a breeding colony of Sprague-Dawley rats homozygous for an autosomal recessive mutation mf ("mutilated foot") associated with a peripheral sensory neuropathy have been found unexpectedly to suffer spontaneous epileptiform attacks. Seizures ranged from brief episodes of compulsive running to tonic-clonic convulsions lasting for up to 30 s, recurring at intervals of hours or days. EEG recordings during seizures showed high-voltage 8-10 Hz spike trains that abated over the ensuing 1-2 min. Interictal records were usually normal. Twice-daily kindling of the amygdala (200 microA sinewave for 1.0 s) was unexpectedly ineffective. Most of the rats that had suffered spontaneous seizures failed to develop kindled afterdischarges, even after 30 kindling stimulations. Other mf rats developed prolonged high-amplitude kindled afterdischarges that were arrested at stage 2 and failed to evolve into convulsive seizures. Hippocampal dentate granule cells of kindled mf rats, stained for zinc by Timm's method, showed significantly less mossy fibre sprouting than wild-type Sprague-Dawley rats after the same number of kindled afterdischarges. A minority of the mf rats tested (2 of 14) kindled normally. Auditory stimulation (n = 23) or stroboscopic flicker (n = 14) failed to elicit seizures or running fits in any mf rat. Peripheral neuropathy corresponding to that in the mf rat, with resistance to kindling and diminished mossy fibre sprouting, have also been reported in transgenic mice with defective p75NGFR neurotrophin receptors. A homologous genetic defect in the rat could account for most of the features of the mf phenotype.

Mitochondrial DNA levels in the brain of HIV-positive patients after zidovudine therapy.

Previous studies have shown that the antiviral nucleoside analogue zidovudine (AZT) depletes levels of mitochondrial DNA (mtDNA) in muscle of patients on long-term therapy. In this study we found that in a similar group of eight HIV-positive patients receiving AZT there was no depletion of brain mtDNA. This finding suggests that AZT-related mtDNA depletion is not a contributing factor in the HIV encephalopathy that occurs in a proportion of HIV-positive patients receiving this antiviral agent.

Quantification of HIV DNA in the brain by PCR: differences between fresh frozen and formalin fixed tissue.

HIV-1 DNA extracted from frozen and formalin fixed brain tissue can be detected using PCR. This work has been extended by amplifying, using semiquantitative PCR, HIV DNA extracted from frontal lobe tissue of 16 patients with AIDS (eight positive and eight negative for p24 antigen). DNA was amplified using HIV-1 pol gene digoxigenin labelled primers and detected by chemiluminescence and densitometry. Cloned standards were amplified in parallel for quantification. HIV DNA levels detected in frozen tissue showed a correlation with p24 positivity and the severity of the histological diagnosis. This correlation was less clear in the formalin fixed material.

The effects of formalin fixation on the detection of apoptosis in human brain by in situ end-labelling of DNA.

The technique of DNA in situ end-labelling (ISEL) for the detection of apoptotic cells has recently become the method of choice. The incorporation of a labelled nucleotide to facilitate detection into the single-stranded region of DNA cleaved by endogenous nucleases has proved to be a sensitive and straightforward technique. Previous reports have applied the technique to the study of apoptotic cells in brain tissue, which is normally subjected to relatively long-term formalin fixation. In this study we have examined the effects of long-term formalin fixation on the ability to detect apoptosis using ISEL in a variety of pathologies and in a normal rat testis. In the tissues which had been treated with overnight formalin fixation, apoptotic cells were readily identified in those pathologies where it might be expected to occur. However, in tissue which had been fixed for several weeks or more, apoptotic cells were not detectable. Samples of brain lymphoma tissue and rat testis subjected to a prospective analysis with respect to fixation time showed that the ability to detect apoptotic cells tailed off at around 3-5 weeks. In order to obviate the risk of false negative results it would be desirable to use ISEL in tissues formalin fixed for less than this period.

Treatment of a man with a mild learning disability who was sexually assaulted whilst in prison.

The aim of this study is to describe the psychological effects on a man with a mild learning disability who was sexually assaulted whilst in prison, and the treatment which was carried out. J. suffered Post-Traumatic Stress Disorder (PTSD), as defined in DSM-III-R, combined with associated features of depression and anxiety. Treatment involved imaginal exposure to the assault, followed by systematic desensitization to the traumatic experience of imprisonment preceding the assault. Activities were also carried out to develop J.'s self-esteem, coping strategies and anxiety management. The successful outcome of treatment is discussed in relation to models of emotional processing. Some discrepancies between scores on self-evaluation questionnaires and behavioural observations raise issues concerning the best way of assessing treatment outcome for people with learning disabilities.

Quantification of HIV by PCR in monocytes and lymphocytes in patients receiving antiviral treatment and low dose recombinant human granulocyte macrophage colony stimulating factor.

Neutropenia induced by antiviral treatment, in particular AZT, can be improved with recombinant human granulocyte macrophage colony stimulating factor (RHGMCSF) in HIV positive patients. However, there has been concern that this may increase the HIV load in the mononuclear cells of such patients. Five patients receiving AZT plus low dose RHGMCSF are reported. There was no consistent change in the levels of HIV DNA in the monocytes and lymphocytes. Additionally, all patients had stable disease with no opportunistic infection during the study period. It is concluded, therefore, that low dose RHGMCSF does not significantly change the viral DNA load in patients receiving AZT.

CD4+ lymphocytopenia due to common variable immunodeficiency mimicking AIDS.

There are an increasing number of published reports of patients with acquired immunodeficiency without evidence of HIV infection, who have been labelled as having "idiopathic CD4+ lymphocytopenia". The case is reported here of a young man who presented with Pneumocystis carinii pneumonia (PCP), CD4+ lymphopenia, and hypogammaglobulinaemia attributable to common variable immunodeficiency (CVID). The presentation of this condition, with many of the clinical and laboratory features of AIDS, highlights CVID as a diagnosis to be considered in the differential diagnosis of CD4+ lymphocytopenia.

Identification of hepatitis B virus-DNA in the liver by in situ hybridization using a biotinylated probe. Relation to HBcAg expression and histology.

The cellular localisation of hepatitis B virus (HBV)-DNA in liver tissue was studied by in situ hybridisation using biotinylated and radiolabelled probes on samples from HBsAg carriers with a spectrum of disease and related to the presence of HBV-DNA in serum and intrahepatic HBcAg expression. Sixteen of the 31 patients studied were seropositive for HBV-DNA; nine had chronic active hepatitis and seven had chronic persistent hepatitis. HBV-DNA was detected in the liver tissue in seven of these patients. In each, HBV-DNA was detected in both cytoplasm and nuclei. All seven also had nuclear and/or cytoplasmic HBcAg which in six was associated with chronic active hepatitis. HBcAg (without tissue HBV-DNA) was detected in the remaining nine patients with an exclusively nuclear pattern in two. Fifteen patients were seronegative for HBV-DNA. HBV-DNA was not detected in the tissue of any of these. Three of these were HBcAg positive but in each this was confined to occasional nuclei and each had inactive disease. The close association between the presence of detectable HBV-DNA in tissue, cytoplasmic HBV-DNA expression and chronic active hepatitis in one group and a failure to detect HBV-DNA in those with nuclear HBcAg and benign disease suggests that there may be two distinct patterns of HBV replication in chronic HBV carriers which may influence the development of liver damage.

Detection of HIV in haemopoietic progenitors.

Peripheral blood cytopenias present a major problem in the management of patients with HIV infection. Their pathophysiology is likely to be multifactorial, although there is controversy as to whether haemopoietic progenitors are a target for HIV. In order to investigate the haemopoietic defect in HIV infection, we looked at bone marrow culture characteristics of marrow from eight HIV+ patients compared to normal controls. We performed long-term liquid culture (LTC) and colony forming assays for granulocyte-macrophage (CFU-GM) and granulocyte, erythroid, megakaryocyte, macrophage (CFU-GEMM). In LTC we found normal stromal appearance and haemopoietic focus formation. There was no difference in colony assays of CFU-GM and CFU-GEMM between HIV+ and normal controls. Colonies taken from CFU-GM and CFU-GEMM were analysed for HIV DNA sequences, and we were able to detect HIV DNA in colonies from all HIV+ patients. Our results indicate that despite infection of haemopoietic progenitor cells by HIV, bone marrow function is preserved. This suggests that HIV-related cytopenias may be due to alternative mechanisms not present in our in vitro system.

Hepatic interferon-alpha gene transcripts and products in liver specimens from acute and chronic hepatitis B virus infection.

In this study we have examined the localization of interferon-alpha in liver tissue from acute and chronic hepatitis B virus carriers to establish whether the defect in interferon-alpha production reported in chronic hepatitis B virus infection is at a pretranscriptional or posttranscriptional level using in situ hybridization and immunohistochemical techniques. Interferon-alpha messenger RNA transcripts and the immunoreactive protein were abundant in liver tissue and in particular in hepatocytes from patients with acute hepatitis B virus infection who subsequently recovered. In contrast interferon-alpha polypeptide was present in a significantly lower number of sinusoidal cells, mononuclear cells and hepatocytes in chronic hepatitis B virus carriers. Although a high proportion of patients with chronic hepatitis B virus infection had cells that expressed interferon-alpha messenger RNA transcripts, the number of such cells was significantly less than in acute hepatitis B virus infection, indicating that the defect in the hepatic interferon-alpha synthesis is at the level of gene activation. Furthermore, using double immunohistochemical staining, the number of hepatocytes containing HBcAg correlated inversely with the proportion of neighboring sinusoidal cells expressing interferon-alpha. These data support previous observations that interferon-alpha production is reduced in chronic hepatitis B virus infection and are consistent with the view that this cytokine is important in the clearance of the virus.

Detection of hepatitis B virus DNA sequences in liver in HBsAg seronegative patients with liver disease with and without anti-HBc antibodies.

Excluding studies from Brechot and co-workers, little support has been found for a role of the hepatitis B virus in the pathogenesis of HBsAg seronegative patients with predominantly chronic liver diseases, including primary liver cancer. In this study liver DNA from 59 predominantly British patients (four cases with paired biopsies, 6-12 months apart) with different, mostly chronic, liver diseases was analysed by molecular hybridization. All were seronegative for HBsAg and serum hepatitis B virus DNA (dot blot hybridization) and their liver diseases were believed to be unrelated to hepatitis B virus infection. Hepatitis B virus DNA was detected in liver of 11 (18.6 per cent) patients; nine had episomal (3.2 Kb) DNA and eight had higher molecular weight bands suggesting integrated forms. Six patients were also seronegative for anti-HBc. Patients of UK and non-UK origin were equally represented. Hepatitis B virus DNA was detected in serum of six of nine patients tested using the polymerase chain reaction. The detection of hepatitis B virus DNA in liver and in serum by this assay in a significant proportion of patients with chronic liver disease, hitherto unsuspected of being hepatitis B virus-related, suggests a possible role for this virus in low- as well as high-prevalence countries.