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Biomedical subjects

J Chapman

Publications and source records attributed to J Chapman.

At least 181 records · Page 10Linked to original sources
PubMed1999

Antiphospholipid antibodies permeabilize and depolarize brain synaptoneurosomes.

Antiphospholipid antibodies (aPL) are associated with neurological diseases such as stroke, migraine, epilepsy and dementia and are thus associated with both vascular and non-vascular neurological disease. We have therefore examined the possibility that these antibodies interact directly with neuronal tissue by studying the electrophysiological effects of aPL on a brain synaptosoneurosome preparation. IgG from patients with high levels of aPL and neurological involvement was purified by protein-G affinity chromatography as was control IgG pooled from ten sera with low levels of aPL. Synaptoneurosomes were purified from perfused rat brain stem. IgG from the patient with the highest level of aPL at a concentration equivalent to 1:5 serum dilution caused significant depolarization of the synaptoneurosomes as determined by accumulation of the lipophylic cation [3H]-tetraphenylphosphonium. IgG from this patient as well as IgG from two elderly patients with high levels of aPL were subsequently shown to permeabilize the synaptosomes to labeled nicotinamide adenine dinucleotide (NAD) and pertussis toxin-ADP-ribose transferase (PTX-A protein) as assayed by labeled ADP-ribosylation of G-proteins in the membranes. No such effects were seen with the control IgG. aPL may thus have the potential to disrupt neuronal function by direct action on nerve terminals. These results may explain some of the non-thromboembolic CNS manifestations of the antiphospholipid syndrome.

Adult↗
PubMed1999

A point mutation inactivating the sulfonylurea receptor causes the severe form of persistent hyperinsulinemic hypoglycemia of infancy in Finland.

Mutations in genes encoding the ATP-regulated potassium (K(ATP)) channels of the pancreatic beta-cell (SUR1 and Kir6.2) are the major known cause of persistent hyperinsulinemic hypoglycemia of infancy (PHHI). We collected all cases of PHHI diagnosed in Finland between 1983 and 1997 (n = 24). The overall incidence was 1:40,400, but in one area of Central Finland it was as high as 1:3,200. Haplotype analysis using polymorphic markers spanning the SUR1/Kir6.2 gene cluster confirmed linkage to the 11p region. Sequence analysis revealed a novel point mutation in exon 4 of SUR1, predicting a valine to aspartic acid change at amino acid 187 (V187D). Of the total cases, 15 affected individuals harbored this mutation in heterozygous or homozygous form, and all of these had severe hyperinsulinemia that responded poorly to medical treatment and required subtotal pancreatectomy. No K(ATP) channel activity was observed in beta-cells isolated from a homozygous patient or after coexpression of recombinant Kir6.2 and SUR1 carrying the V187D mutation. Thus, the mutation produces a nonfunctional channel and, thereby, continuous insulin secretion. This unique SUR1 mutation explains the majority of PHHI cases in Finland and is strongly associated with a severe form of the disease. These findings provide diagnostic and prognostic utility for suspected PHHI patients.

ATP-Binding Cassette Transporters↗
PubMed1999

Homozygotes for oculopharyngeal muscular dystrophy have a severe form of the disease.

Autosomal dominant oculopharyngeal muscular dystrophy (OPMD) usually begins with ptosis or dysphagia during the fifth or sixth decade of life. We studied 7 patients with OPMD symptoms starting before the age of 36 years. All were found to be homozygotes for the dominant (GCG)9 OPMD mutation. On average, disease onset was 18 years earlier than in heterozygotes, and patients had a significantly larger number of muscle nuclei containing intranuclear inclusions (INIs) (9.4 vs 4.9%).

Adult↗
PubMed1998

Cytomegalovirus and human herpesvirus 6 both cause viral disease after renal transplantation.

BACKGROUND: Systemic viral disease after renal transplantation, especially after treatment with OKT3 or antithymocyte globulin, has usually been attributed to cytomegalovirus (CMV) infection. Identification of human herpesvirus 6 (HHV6) has raised the possibility that infection or reactivation of this virus may also occur in the same setting. METHODS: We thus examined the incidence of CMV and HHV6 infection in a prospective blinded consecutive series of 30 renal and renal/pancreas transplant patients, 22 of whom received OKT3, antithymocyte globulin, or both. RESULTS: Clinical diagnosis of a viral syndrome was made in 15 patients. Three patients with only HHV6 DNA in urine or serum had fever and abnormal liver function but not neutropenia. All five CMV-seronegative patients who received positive kidneys developed moderate to severe disease with fever and neutropenia but also had HHV6 DNA in urine or serum. Seven CMV-seropositive patients developed disease, mostly after OKT3/antithymocyte globulin, but six shed both CMV and HHV6 in urine or serum. The simultaneous detection of both HHV6 and CMV DNA in either urine or serum was the strongest predictor of disease (and also the severity of disease), with an odds ratio of 99.0 (95% confidence intervals 5.4-1814, P<0.002). CONCLUSION: Most systemic viral disease after renal transplantation may be due to either coinfection or reactivation of CMV and HHV6 together. A wider understanding of risk factors for severe viral disease in this setting may come from testing for both viruses in all donors and patients in both clinical practice and clinical trials.

Acyclovir↗
PubMed1998

Activation of proliferator-activated receptors alpha and gamma induces apoptosis of human monocyte-derived macrophages.

Peroxisome proliferator-activated receptors (PPARs) have been implicated in metabolic diseases, such as obesity, diabetes, and atherosclerosis, due to their activity in liver and adipose tissue on genes involved in lipid and glucose homeostasis. Here, we show that the PPARalpha and PPARgamma forms are expressed in differentiated human monocyte-derived macrophages, which participate in inflammation control and atherosclerotic plaque formation. Whereas PPARalpha is already present in undifferentiated monocytes, PPARgamma expression is induced upon differentiation into macrophages. Immunocytochemistry analysis demonstrates that PPARalpha resides constitutively in the cytoplasm, whereas PPARgamma is predominantly nuclear localized. Transient transfection experiments indicate that PPARalpha and PPARgamma are transcriptionally active after ligand stimulation. Ligand activation of PPARgamma, but not of PPARalpha, results in apoptosis induction of unactivated differentiated macrophages as measured by the TUNEL assay and the appearance of the active proteolytic subunits of the cell death protease caspase-3. However, both PPARalpha and PPARgamma ligands induce apoptosis of macrophages activated with tumor necrosis factor alpha/interferon gamma. Finally, PPARgamma inhibits the transcriptional activity of the NFkappaB p65/RelA subunit, suggesting that PPAR activators induce macrophage apoptosis by negatively interfering with the anti-apoptotic NFkappaB signaling pathway. These data demonstrate a novel function of PPAR in human macrophages with likely consequences in inflammation and atherosclerosis.

Apoptosis↗
PubMed1998

Molecular cloning of the cDNA encoding the carboxy-terminal domain of chimpanzee apolipoprotein(a): an Asp57 --> Asn mutation in kringle IV-10 is associated with poor fibrin binding.

Insight into the structural features of human lipoprotein(a) [Lp(a)] which underlie its functional implication in fibrinolysis may be gained from comparative studies of apo(a). Indeed, cloning of rhesus monkey apo(a) has shown that a Trp72 --> Arg mutation in the lysine-binding site (LBS) of KIV-10 leads to loss of lysine-binding properties of the rhesus Lp(a) particle. Consequently, comparative studies of apo(a) sequences in different Old World monkey species should further our understanding of the molecular role of Lp(a) in the fibrinolytic process. In contrast to other Old World monkeys, including rhesus monkey, cynomolgus, and baboon, the chimpanzee exhibits an elevated level of Lp(a) and a distinct isoform distribution as compared to humans [Doucet et al. J. Lipid Res. (1994) 35, 263-270]. Clearly then, the chimpanzee is an interesting animal model for study of the structure, function, and potential pathophysiological roles of Lp(a). We have cloned and sequenced the region of chimpanzee apo(a) cDNA spanning KIV-3 to the stop codon. The global organization of this region is similar to that of human apo(a) with the presence of KV, which is absent in rhesus monkey apo(a). Nucleotide sequence comparison indicates a variation of 1.4% between chimpanzee and man and 5.1% between chimpanzee and rhesus monkey. The differences concerned single base changes. An Asp57 --> Asn mutation was detected in KIV-10; this residue is critical to the LBS of KIV-10 in human apo(a). To verify that the Asp57 --> Asn substitution was specific to apo(a), we have also cloned the cDNA-encoding plasminogen, which exhibited an Asp at the corresponding position in kringle IV. Using an in vitro binding assay, we have demonstrated that chimpanzee Lp(a) exhibits poor lysine-specific interaction with both intact and plasmin-degraded fibrin as compared to its human counterpart. We propose that the Asn57 substitution in KIV-10 of chimpanzee apo(a) is responsible for this property. Chimpanzee Lp(a) therefore represents an appropriate particle with which to explore the potential effects of Lp(a) on the fibrinolytic system, such as the inhibition of plasminogen activation or inhibition of t-PA activity.

Amino Acid Substitution↗
PubMed1998

Elevated lipoprotein(a) levels and small apo(a) isoforms are compatible with longevity: evidence from a large population of French centenarians.

Epidemiological studies have shown lipoprotein(a) (Lp(a)) to be an independent risk factor for cardiovascular disease. Lp(a) is a cholesterol-rich, low-density lipoprotein (LDL)-like particle to which a large glycoprotein, apolipoprotein(a) (apo(a)) is attached. Plasma Lp(a) levels are highly genetically determined and influenced to a minor degree by environmental factors. In an effort to determine whether Lp(a) might be associated with longevity, we have evaluated Lp(a) levels and apo(a) isoform sizes in a population of French centenarians (n = 109) compared to a control group (n = 227). The mean age of centenarians was 101.5 +/- 2.4 years while the control group was 39.4 +/- 7.2 years. Plasma levels of total cholesterol and triglyceride were within the normal range in both centenarian and control subjects. Lp(a) levels were higher in centenarians (both male and female) than in the normolipidemic control group (mean Lp(a) level = 0.33 +/- 0.42 and 0.22 +/- 0.27 mg/ml, respectively, P < 0.005). The distribution of apo(a) isoforms was significantly shifted towards small isoform size in the centenarian population as compared to the controls (54.4 and 41.4% of isoforms < or = 27 kringles (kr), respectively, P = 0.04). Nonetheless, the apo(a) size distribution in centenarians did not entirely explain the high Lp(a) levels observed in this population. Factors other than apo(a) size, and which may be either genetic or environmental in nature, appear to contribute to the elevated plasma Lp(a) levels of our centenarian population. We conclude therefore that high plasma Lp(a) levels are compatible with longevity.

Adult↗
PubMed1998

Why do GPs perform investigations?: The medical and social agendas in arranging back X-rays.

OBJECTIVE: We aimed to determine the most important medical and psychosocial reasons GPs report for requesting back X-rays. METHODS: All GPs in a single health district were mailed a questionnaire and asked to document their reasons for requesting back X-rays. RESULTS: A total of 166/236 (70%) of GPs responded. There were 445 comments (mean 2.7 per doctor): 319 (72%) were medical indications (mean 1.9 per doctor) and 126 (28%) psychosocial reasons (mean 0.8 per doctor). GPs' medical criteria for requesting back X-rays were mainly in line with current guidelines. The most common psychosocial reasons were patient satisfaction (17%), work related (14%) and reassurance (8%). CONCLUSION: GPs' reported medical criteria for arranging back X-rays are mainly 'appropriate', but psychosocial reasons-especially patient satisfaction and reassurance-are also likely to be important factors. If psycho-social agendas are important in ordering investigations, then clinical guidelines which discuss only medical criteria may not be effective in reducing 'inappropriate' investigations.

Back Pain↗
PubMed1998

Apolipoprotein E4 in Parkinson disease and dementia: new data and meta-analysis of published studies.

The authors examined whether the epsilon4 allele might be associated with dementia in Parkinson disease (PD), given that the dementia of PD shares neuroanatomic and neurochemical features with Alzheimer disease (AD) and that many recent studies have found a high prevalence of the epsilon4 allele of apolipoprotein E (ApoE) in AD. The authors examined patients with PD (n=125, 47 demented) and unrelated controls (n=93) using a short mental test. DNA was obtained from blood leukocytes. The relevant portion of the apolipoprotein E (ApoE) gene was amplified by polymerase chain reaction, and the epsilon4 allele was identified using a restriction enzyme. The frequency of the ApoE epsilon4 allele in demented patients with PD (14%) was not greater than that in nondemented patients (17%), whereas patients with PD as a whole showed a trend toward a higher epsilon4 allele frequency (16%) than age-matched controls (10%, p=0.07). The epsilon4 allele frequency in nondemented patients with PD was significantly higher than in controls (p=0.055). These results and the meta-analysis of four published reports fail to support the hypothesis that the epsilon4 allele is associated with dementia in PD.

Aged↗
PubMed1998

Identification in Israel of 2 Jewish Creutzfeld-Jakob disease patients with a 178 mutation at their PrP gene.

Among the dozen known mutations in the PrP gene which segregate with the inherited prion diseases, only 2 mutations have been described in Israel so far: the codon 200 mutation in Creutzfeldt-Jakob disease (CJD) affected Libyan Jews, and the codon 102 mutation in 1 Jewish Gerstmann-Straussler-Scheinker (GSS) affected pedigree of German origin. We report here 2 unrelated CJD178 cases affected by a unique phenotype: aphemia, apraxia, uncontrolled laugh and no ataxia. As opposed to other CJD178 patients, in these patients, the signal transduction protein 14-3-3, recently suggested as a CJD marker, was detected in the cerebrospinal fluid samples by immunostaining. The D178N mutation, known to be linked to 2 different phenotypes: Fatal Familial Insomnia (FFI) and CJD, was not described so far among Jews. The phenotype reported here, although it shares a common Va1129/Asn178 haplotype with the previously described CJD178, may point to a different clinical subtype of CJD178.

Behavioral Symptoms↗
PubMed1998

Chimpanzee lipoprotein(A): Relationship between apolipoprotein(A) isoform size and the density profile of lipoprotein(A) in animals with different heterozygous apo(A) phenotypes.

In a previous study [C. Doucet et al., J. Lipid Res 35:263-270, 1994], we have shown that plasma lipoprotein (a) [Lp(a)] levels were significantly elevated in a population of unrelated chimpanzees as compared to those in normolipidemic human subjects. Nonetheless, the inverse correlation between Lp(a) levels and apolipoprotein (a) [apo(a)] isoforms typical of man was maintained in the chimpanzee. In the present study, we describe the density profiles of apo B- and apo A1-containing lipoproteins and of Lp(a) in chimpanzee plasmas heterozygous for apo(a) isoforms after fractionation by single spin ultracentrifugation in an isopycnic gradient. The distribution of apo(a) isoforms in the density gradient was also examined by SDS-agarose gel electrophoresis and immunoblotting using chemiluminescence detection. In all double-band phenotypes examined, the smallest isoform was present along the entire length of the density gradient. The density distribution of the second isoform varied according to the size difference between the respective isoforms. Two isoforms close in size (difference in apparent molecular mass = 60 kDa) were present together in every gradient subfraction. On the contrary, when the two isoforms displayed distinct molecular mass (maximal difference in apparent molecular mass = 340 kDa), then the largest was principally present in the densest fractions of the gradient (d > 1.1 mg/ml). These observations suggest that Lp(a) particles with small apo(a) isoforms are more susceptible to interact with other lipoproteins than are Lp(a) particles with large isoforms.

Animals↗
PubMed1998

Pulmonary function, exercise performance, and growth in survivors of congenital diaphragmatic hernia.

A cohort of survivors of congenital diaphragmatic hernia (CDH), with matched controls, was studied to assess growth, respiratory function, and exercise performance. Nineteen of 24 survivors from an 11 year period (79%) were compared with 19 matched controls. Subjects had detailed auxology, performed spirometry and cycle ergometry, and completed questionnaires about respiratory symptoms and exercise. There were no significant differences between the groups for height, weight, sitting height, head circumference, or body mass index expressed as SD scores. The mean (95% confidence interval) percentage predicted forced vital capacity (FVC) was 84.7% (79.1 to 90.3) in index cases and 96.5% (91.4 to 101.6) in controls (p < 0.01). There was no significant difference in total lung capacity. Expiratory flow rates corrected for FVC were also similar between groups, suggesting normal airway function relative to lung size. Mean maximum oxygen consumption in ml/kg/min was 40.1 (36.8 to 43.4) and 42.2 (38.5 to 45.8) in index and control cases. These differences were not significant. Index cases achieved a similar minute ventilation to controls by more rapid and shallower breathing. Index cases had lower perception of their own fitness and lower enjoyment of exercise, although habitual activity levels were similar. Survivors of CDH repair have reduced functional lung volumes, but normal airway function compared with matched controls. They have no growth impairment nor significant impairment of exercise performance, although they have more negative perceptions of their own fitness. They should be encouraged and expected to participate fully in sport and exercise.

Child↗
PubMed1998

ACE, MTHFR, factor V Leiden, and APOE polymorphisms in patients with vascular and Alzheimer's dementia.

BACKGROUND AND PURPOSE: There is a growing interest in the use of genetic markers in the differential diagnosis of dementia. In the current study we examined the usefulness of genetic risk factors for vascular disease as markers for vascular dementia (VD). METHODS: The groups included 41 patients with VD, 49 patients with dementia of the Alzheimer's type, and 40 age-matched control subjects without dementia. These patients were genotyped for vascular disease-associated polymorphisms in the genes coding for methylenetetrahydrofolate reductase (MTHFR), angiotensin-converting enzyme (ACE), factor V Leiden (FVL), and a common genetic risk factor for AD, apolipoprotein E epsilon4 (APOE epsilon4). RESULTS: There was no significant association between ACE, MTHFR, and FVL genotypes with VD whether compared with subjects with AD or with control subjects. There was a higher frequency of APOE epsilon4 alleles in patients with AD (30%, P=0.016) and VD (26%, P=0.07) compared with control subjects (15%). CONCLUSIONS: VD is not associated with the genetic risk factors for vascular disease examined in this study, indicating that the pathogenesis of VD may differ from other vascular diseases.

Aged↗
PubMed1998

APOE in non-Alzheimer amyloidoses: transmissible spongiform encephalopathies.

BACKGROUND: The APOE genotype has been shown to influence the risk of developing sporadic and familial AD. This effect is isoform-dependent, the APOE epsilon4 allele increasing susceptibility and the APOE epsilon2 allele providing protection. Amyloid formation is an important part of the pathogenesis in AD as well as in spongiform encephalopathies; apoE deposition in amyloid plaques has been documented in both conditions. METHODS: We examined the frequency of the APOE alleles in patients with various forms of transmissible spongiform encephalopathies, or prion diseases, including sporadic and iatrogenic Creutzfeldt-Jakob disease; familial Creutzfeldt-Jakob disease associated with PRNP 178N/129V and 200K/129M point mutations and a 24-nucleotide repeat expansion; fatal familial insomnia caused by the 178N/129M mutation; Gerstmann-Sträussler-Scheinker disease associated with 102L/129M mutation; and kuru. RESULTS: None of the groups we studied had a significant excess of APOE epsilon4 allele when compared with appropriate controls. CONCLUSION: Our results do not support the contention that the APOE epsilon4 allele is a risk factor for developing Creutzfeldt-Jakob disease or related disorders.

Alleles↗
PubMed1998

Antineurofilament antibodies in postpolio syndrome.

We determined the levels of antineurofilament antibodies in 29 patients with postpolio syndrome (PPS), 26 stable postpolio (PP) patients, 22 patients with ALS, and 20 normal controls (NCs). Patients with PPS had higher antibody levels to cholinergic neurofilaments than did all other groups. PP patients and those with ALS had antibody levels similar to those of NCs. The antibody binding level showed no relation to the age of the patients, duration of disease, or motor score.

Adult↗
PubMed1998

188Re(V)-DMSA revisited: preparation and biodistribution of a potential radiotherapeutic agent with low kidney uptake.

Methods of preparation and biodistribution in mice of tin-free 99Tcm(V)-DMSA and 188Re(V)-DMSA, a potential matching pair of radiopharmaceuticals for diagnosis and therapy of certain cancers, are described. Preparation of tin-free 188Re(V)-DMSA (I) is based on reduction with either SO2-releasing compounds like Na2S2O4 (30 mg Na2S2O4, 10 mg DMSA, 1 mg L-ascorbic acid, 37 degrees C, 60 min incubation), Na2S2O5 (as before, 70 degrees C, 15 min incubation), or HBr (0.2 ml 48% HBr, 0.2 ml 7 M HCl, 10 mg DMSA, 1 mg L-ascorbic acid, 70 degrees C, 60 min incubation). I exhibits significantly lower kidney uptake than tin-containing 188Re(V)-DMSA (II) (2-3% and 49% injected dose per gram organ, 1 h post-injection, respectively). HPLC profiles of I and II are similar. DMSA excess in tin-free 188Re(V)-DMSA is not responsible for the low kidney uptake of I. High kidney uptake of II is explained by formation of a mixed 188Re(V)-Sn-DMSA complex in vivo. Age-linked bone uptake in mice dependent on the maturation of the bone is demonstrated for both I and II.

Aging↗
PubMed1998

Mothers' perceptions of the care-by-parent program prior to hospital discharge of their preterm infants.

PURPOSE: This research was conducted to gain an understanding of the care-by-parent experience for mothers of preterm infants. DESIGN: Phenomenologic methodology was used to explore the experiences of six mothers. Each participant slept overnight with her infant in a private hospital room. The mother assumed responsibility for her infant's care, knowing that nursing staff assistance was available if needed. Interviews were conducted on the following day and again after the infant had been home at least four days. SAMPLE: The participants were six mothers of preterm infants. MAIN OUTCOME VARIABLE: Mothers' experiences as they assumed responsibility in caring for their preterm infants away from the intensive care nursery. RESULTS: Findings revealed that the care-by-parent experience gives the mother an opportunity to assume full responsibility for her preterm infant's care, tests the reality of caregiving, helps her learn about caregiving activities and her infant's patterns of behavior, and confirms her readiness for independent parenting and the infant's readiness for discharge home. These findings confirm the benefits of rooming-in prior to discharge of preterm infants and provide guidelines for discharge planning.

Attitude to Health↗