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Biomedical subjects

J R Kerr

Publications and source records attributed to J R Kerr.

At least 19 recordsLinked to original sources
PubMed2006

Chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) is thought to have a worldwide prevalence of 0.4-1% with approximately 240,000 patients in the UK. Diagnosis is based on clinical criteria and critically depends on exclusion of other physical and psychiatric diseases. Studies of pathogenesis have revealed immune system abnormalities and chronic immune activation, dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, brain abnormalities, evidence of emotional stress (comprising host aspects) and evidence of exogenous insults, for example, various microbial infections (Epstein-Barr virus, enteroviruses, parvovirus B19, Coxiella burnetii and Chlamydia pneumoniae), vaccinations and exposure to organophosphate chemicals and other toxins (comprising environmental aspects). Emotional stress appears to be very important as it reduces the ability of the immune system to clear infections, it's presence has been shown to determine whether or not an individual develops symptoms upon virus infection, and it leads to activation of the HPA axis. But, emotional stress is distinct from depression, the presence of which precludes a diagnosis of CFS. There is no specific treatment for CFS other than the much underutilised approach of specific treatment of virus infections. Current priorities are to understand the molecular pathogenesis of disease in terms of human and virus gene expression, to develop a diagnostic test based on protein biomarkers, and to develop specific curative treatments.

Diagnosis, Differential↗
PubMed2006

Current research priorities in chronic fatigue syndrome/myalgic encephalomyelitis: disease mechanisms, a diagnostic test and specific treatments.

Chronic fatigue syndrome (CFS) is an illness characterised by disabling fatigue of at least 6 months duration, which is accompanied by various rheumatological, infectious and neuropsychiatric symptoms. A collaborative study group has been formed to deal with the current areas for development in CFS research--namely, to develop an understanding of the molecular pathogenesis of CFS, to develop a diagnostic test and to develop specific and curative treatments. Various groups have studied the gene expression in peripheral blood of patients with CFS, and from those studies that have been confirmed using polymerase chain reaction (PCR), clearly, the most predominant functional theme is that of immunity and defence. However, we do not yet know the precise gene signature and metabolic pathways involved. Currently, this is being dealt with using a microarray representing 47,000 human genes and variants, massive parallel signature sequencing and real-time PCR. It will be important to ensure that once a gene signature has been identified, it is specific to CFS and does not occur in other diseases and infections. A diagnostic test is being developed using surface-enhanced, laser-desorption and ionisation-time-of-flight mass spectrometry based on a pilot study in which putative biomarkers were identified. Finally, clinical trials are being planned; novel treatments that we believe are important to trial in patients with CFS are interferon-beta and one of the anti-tumour necrosis factor-alpha drugs.

Fatigue Syndrome, Chronic↗
PubMed2005

Association of chronic fatigue syndrome with human leucocyte antigen class II alleles.

BACKGROUND: A genetic component to the development of chronic fatigue syndrome (CFS) has been proposed, and a possible association between human leucocyte antigen (HLA) class II antigens and chronic fatigue immune dysfunction has been shown in some, but not all, studies. AIMS: To investigate the role of HLA class II antigens in CFS. METHODS: Forty nine patients with CFS were genotyped for the HLA-DRB1, HLA-DQA1, and HLA-DQB1 alleles and the frequency of these alleles was compared with a control group comprising 102 normal individuals from the UK. All patients and controls were from the same region of England and, apart from two patients, were white. RESULTS: Analysis by 2 x 2 contingency tables revealed an increased frequency of HLA-DQA1*01 alleles in patients with CFS (51.0% v 35%; odds ratio (OR), 1.93; p = 0.008). HLA-DQB1*06 was also increased in the patients with CFS (30.2% v 20.0%; OR, 1.73, p = 0.052). Only the association between HLA-DQA1*01 and CFS was significant in logistic regression models containing HLA-DQA1*01 and HLA-DRQB1*06, and this was independent of HLA-DRB1 alleles. There was a decreased expression of HLA-DRB1*11 in CFS, although this association disappeared after correction for multiple comparisons. CONCLUSIONS: CFS may be associated with HLA-DQA1*01, although a role for other genes in linkage disequilibrium cannot be ruled out.

Adult↗
PubMed2005

Gene expression in peripheral blood mononuclear cells from patients with chronic fatigue syndrome.

BACKGROUND: Chronic fatigue syndrome (CFS) is a multisystem disease, the pathogenesis of which remains undetermined. AIMS: To test the hypothesis that there are reproducible abnormalities of gene expression in patients with CFS compared with normal healthy persons. METHODS: To gain further insight into the pathogenesis of this disease, gene expression was analysed in peripheral blood mononuclear cells from 25 patients with CFS diagnosed according to the Centers for Disease Control criteria and 25 normal blood donors matched for age, sex, and geographical location, using a single colour microarray representing 9522 human genes. After normalisation, average difference values for each gene were compared between test and control groups using a cutoff fold difference of expression > or = 1.5 and a p value of 0.001. Genes showing differential expression were further analysed using Taqman real time polymerase chain reaction (PCR) in fresh samples. RESULTS: Analysis of microarray data revealed differential expression of 35 genes. Real time PCR confirmed differential expression in the same direction as array results for 16 of these genes, 15 of which were upregulated (ABCD4, PRKCL1, MRPL23, CD2BP2, GSN, NTE, POLR2G, PEX16, EIF2B4, EIF4G1, ANAPC11, PDCD2, KHSRP, BRMS1, and GABARAPL1) and one of which was downregulated (IL-10RA). This profile suggests T cell activation and perturbation of neuronal and mitochondrial function. Upregulation of neuropathy target esterase and eukaryotic translation initiation factor 4G1 may suggest links with organophosphate exposure and virus infection, respectively. CONCLUSION: These results suggest that patients with CFS have reproducible alterations in gene regulation.

Adolescent↗
PubMed2004

A fatal case of disseminated aspergillosis caused by a non-sporulating strain of Aspergillus fumigatus.

This report describes the case of a 38 year old pregnant woman with fatal disseminated aspergillosis and multiorgan failure, which was preceded by a long history of allergic bronchopulmonary aspergillosis. Postmortem revealed massive infarction and abscess formation in both lungs. Histology revealed a focal granulomatous response. Fungal infiltration with areas of necrosis were also seen in the liver, spleen, and paratracheal, mediastinal, para-aortic, and hilar lymph nodes. Culture of tissue samples produced a non-sporulating, beige coloured fungus that developed green pigmentation only after three weeks of incubation. Nucleotide sequencing of the D1-D2 region of the large ribosomal subunit revealed 100% homology with Aspergillus fumigatus. Minimum inhibitory concentrations for amphotericin B and itraconazole were both 0.25 mg/litre (susceptible). Further work is urgently required to determine the prevalence of such non-sporulating strains and their relevance to clinical infection.

Adult↗
PubMed2003

Successful intravenous immunoglobulin therapy in 3 cases of parvovirus B19-associated chronic fatigue syndrome.

Three cases of chronic fatigue syndrome (CFS) that followed acute parvovirus B19 infection were treated with a 5-day course of intravenous immunoglobulin (IVIG; 400 mg/kg per day), the only specific treatment for parvovirus B19 infection. We examined the influence of IVIG treatment on the production of cytokines and chemokines in individuals with CFS due to parvovirus B19. IVIG therapy led to clearance of parvovirus B19 viremia, resolution of symptoms, and improvement in physical and functional ability in all patients, as well as resolution of cytokine dysregulation.

Adult↗
PubMed2003

Cytokine gene polymorphisms associated with symptomatic parvovirus B19 infection.

BACKGROUND: The immune system has been implicated in the pathogenesis of certain clinical manifestations of parvovirus B19 infection, including rash and arthralgia. Cytokines feature in the pathogenesis of parvovirus B19 infection, so inherited variability in cytokine responses to B19 infection might have a bearing on the symptomatology of parvovirus B19 infection. AIMS: To investigate the possible role of cytokine gene polymorphisms in the clinical manifestations of parvovirus B19 infection. METHODS: Thirty six patients with a variety of symptoms at acute infection and follow up (mean, 22.0 months) and controls (99-330, depending on the locus) were examined for the following cytokine polymorphisms: tumour necrosis factor alpha (TNF alpha), -308; interferon gamma (IFN-gamma), +874; interleukin 6 (IL-6), -174; IL-10, -592, -819, and -1082; and transforming growth factor beta1 (TGF beta 1), +869 (codon 10) and +915 (codon 25). RESULTS: The TNF alpha -308*A allele occurred in 13.9% of the parvovirus group compared with 27.0% of the control group (odds ratio (OR), 0.44; p = 0.02). The TGF beta 1 CG/CG haplotype was more frequent in the parvovirus group than in the controls (16.7% v 5%; OR, 4.8; p = 0.02). Within the B19 infected group, the TGF beta 1 +869 T allele was associated with skin rash at acute infection (p = 0.005), whereas at follow up the IFN-gamma +874 T allele was associated with the development of anti-B19 non-structural protein 1 antibodies (p = 0.04). CONCLUSIONS: The results of the present study suggest that inherited variability in cytokine responses may affect the likelihood of developing symptoms during parvovirus infection.

Adolescent↗
PubMed2003

Association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia.

AIMS: To investigate the association of acute parvovirus B19 infection with new onset of acute lymphoblastic and myeloblastic leukaemia. METHODS: Cerebrospinal fluid (CSF) samples from patients with acute myelogenous leukaemia (AML) at diagnosis (n = 2) and acute lymphoblastic leukaemia (ALL) at diagnosis (n = 14) were analysed for parvovirus B19 DNA by means of nested polymerase chain reaction. In addition, samples from patients with benign intracranial hypertension (BIH) (n = 10) and hydrocephalus (n = 13) were tested as controls. RESULTS: Four leukaemia cases were positive-common ALL (n = 2), null cell ALL (n =1), and M7 AML (n = 1)-whereas all controls were negative (Yates corrected chi(2) value, 3.97; p = 0.046; odds ratio, 16.92; confidence interval, 1.03 to 77.18). All four patients were significantly anaemic, but none was encephalitic or had evidence of central nervous system leukaemia. In three of these patients, serum tumour necrosis alpha, interferon gamma, interleukin 6, granulocyte-macrophage colony stimulating factor (range, 34.93-3800.06 pg/ml), and macrophage chemoattractant protein 1 were detectable. All of these four patients carried at least one of the HLA-DRB1 alleles, which have been associated with symptomatic parvovirus B19 infection. CONCLUSION: Erythroid suppression and immune cell proliferation are both associated with B19 infection and may also be important in the pathogenesis of acute leukaemia.

Acute Disease↗
PubMed2002

Evidence for the role of demyelination, HLA-DR alleles, and cytokines in the pathogenesis of parvovirus B19 meningoencephalitis and its sequelae.

OBJECTIVE: To review the clinical and pathological features of parvovirus B19 meningoencephalitis and its sequelae in 12 previously published cases, and to perform additional tests to determine the pathogenesis of the disease. METHODS: Cases were reviewed and available serum and cerebrospinal fluid (CSF) tested for antiganglioside antibodies and a range of cytokines. In situ hybridisation for parvovirus B19 DNA was performed on postmortem brain tissue in two cases. HLA-DRB1 typing was undertaken on genomic DNA extracted from peripheral blood leucocytes. RESULTS: Cerebellar involvement was suggested either clinically or pathologically in four cases. In the two cases with postmortem histology, there was marked atrophy of the molecular and granular layers of the cerebellum with focal loss of Purkinje cells. Brain scanning by MRI or CT was done in six cases during the acute phase. Three were abnormal with evidence of demyelination. Three had markedly enlarged ventricles, in two of which there was high signal intensity from the white matter on both T1 and T2 weighted images. The three cases with abnormal brain scans had long term neurological sequelae (mental retardation, personality change, altered affect). In situ hybridisation on available postmortem brain tissue was negative in the two cases tested. All cases in which HLA-DR alleles were determined carried at least one of the following alleles: HLA-DRB1*01, *04, *07, *09, *15, *16. Available serum and CSF was tested for antiganglioside antibodies (all negative) and for a panel of cytokines, which had a similar profile in both serum (n = 5) and CSF (n = 1) during the acute phase. Cytokines that were consistently detectable were IL-6 (mean 726.20 pg/ml), TNFalpha (50.64 pg/ml), IFNgamma (39.64 pg/ml), GM-CSF (216.12 pg/ml), and MCP-1 (154.43 pg/ml); IL-1beta, IL-5, and IL-13 were undetectable. CONCLUSIONS: HLA-DR associations, an increased cytokine response, and benefit from immunomodulatory treatment (in one case) support a role for the immune response in the pathogenesis of parvovirus B19 meningoencephalitis.

Adolescent↗
PubMed2001

Association of human parvovirus B19 infection with acute meningoencephalitis.

To find out the incidence and clinical presentation of parvovirus B19 meningoencephalitis, we tested samples of cerebrospinal fluid from 162 patients (one from each patient) with undiagnosed meningoencephalitis, who presented between March, 1997, and March, 1998 (an outbreak period) using nested PCR for B19 genes. Seven patients were positive; an incidence of 4.3%. Five additional cases of meningoencephalitis were detected from other years. Three patients with underlying disorders (haemophagocytic lymphohistiocytosis, Cockayne's syndrome, and Turner's syndrome) died. Neurological sequelae were observed in three surviving patients, all of whom had had striking abnormalities detected on brain scans done during the acute phase.

Adolescent↗
PubMed2001

The slope of the psychometric function for Bailey-Lovie letter charts: defocus effects and implications for modeling letter-by-letter scores.

BACKGROUND: Visual acuity measurement often results in an imprecise endpoint because subjects correctly identify some but not all of the letters on one or more size levels on a letter chart. The extent of this transition zone from seeing to nonseeing can be described by probit size, which is calculated by performing Probit Analysis on letter chart data. There has been no previous research into the effects of optical defocus on letter chart probit size. METHODS: We tested 18 young visually normal subjects monocularly during three different defocus conditions: best spectacle correction (zero defocus) and +1.00 D and +2.00 D additions. Stimuli were Bailey-Lovie-style logarithm of the minimum angle of resolution (log MAR) letter charts constructed with a 0.05 logMAR size progression between size levels. Frequency of seeing data from these charts were used to calculate probit size. RESULTS: There were statistically significant effects of optical defocus on mean probit size. After Monte Carlo correction for bias, we believe that true mean values for probit size are about 0.07 logMAR for well-corrected subjects and up to 0.12 logMAR with optical defocus. CONCLUSION: The smaller probit size for well-corrected subjects should correspond to a sharper logMAR visual acuity endpoint and less intrasubject variability in logMAR acuity than for subjects with a larger probit size (optical defocus). Our modeling shows that these different probit sizes can also significantly affect letter-by-letter visual acuity scoring.

Adult↗