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K Morgan

Publications and source records attributed to K Morgan.

At least 217 records · Page 12Linked to original sources
PubMed1992

Linkage study of chronic childhood-onset spinal muscular atrophy (SMA): confirmation of close linkage to D5S39 in French Canadian families.

Chronic childhood-onset spinal muscular atrophy (SMA) is, after Duchenne muscular dystrophy, the most common neuromuscular disorder in childhood. Recent linkage analyses have mapped this disease to 5q12-5q14. We show that chronic SMA (Types II and III) is tightly linked to the marker locus D5S39 (Zmax = 5.47 at theta = 0.02) in eight French Canadian families. In contrast to previously published results, we do not observe close linkage between chronic SMA and D5S6 (Zmax = 0.34 at theta = 0.18) or D5S78 (Zmax = 0.25 at theta = 0.21). Last, we present a family that appears to be discordant for this localization but may represent the first example of an incompletely penetrant individual.

Canada↗
PubMed1992

Genetic control of the immune response to collagen by the major histocompatibility complex in the rat: I. Humoral responses to bovine and chick type II collagen.

A number of congenic and recombinant rat strains with different RT1 haplotypes on a PVG/c background were immunised with native bovine or chick type II collagen. Only strains with the "u" haplotype were good responders to bovine type II collagen whilst all strains responded to chick type II collagen. However, the "u" haplotype was again associated with the production of the highest amounts of antibody. All the strains responded to a non-collagenous antigen, keyhole limpet haemocyanin, showing that this effect was not a general one relating to all antigens. When antibodies were produced to the immunising collagen, binding of antibodies to native rat type II collagen was also seen. This association, of high amounts of antibody with the "u" haplotype, was inherited in a dominant fashion when F1 and F2 hybrids between low responder (RT1a) and high responder (RT1u) were examined. The recombinant r1 (class I av1, class II c) and r8 (class I av1 and class II u) strains showed that "u" haplotype at class II rather than at class I was associated with the strong response to type II collagen. The absence of arthritis in the "u" haplotype rats, suggests that the "u" haplotype alone is insufficient for arthritis induction after immunisation with type II collagen. It suggests that background genes outside the RT1 complex influence arthritis production as Wistar rats with the RT1u haplotype (but different minor genes outside RT1 complex) give an arthritis incidence of 50% under identical immunisation protocols.

Animals↗
PubMed1992

Corneal autoimmunity in patients with peripheral ulcerative keratitis (PUK) in association with rheumatoid arthritis and Wegener's granulomatosis.

Serum antibodies to the cornea were investigated in patients with peripheral ulcerative keratitis (PUK) in isolation or in association with a systemic disease (rheumatoid arthritis or Wegener's granulomatosis). Indirect immunofluorescence on bovine corneal sections demonstrated that antibodies bound to epithelial antigens in two distinct patterns: a lattice-like pattern, probably staining intercellular membrane antigens, and a diffuse pattern covering the entire surface of the epithelium. Both patterns were associated with PUK rather than systemic disease whilst the presence of the lattice pattern was more associated with the onset of the PUK. Immunoblotting of sera to corneal epithelial protein extracts demonstrated that a number of corneal antigens were targeted by antibodies. Two antigens, 54 kDa and 70 kDa, were of particular interest. Antibodies to the 54 kDa antigen, the major corneal-specific antigen, were also detected by enzyme-linked immunosorbent assay (ELISA). Longitudinal studies showed that these antibodies often first occurred after an episode of PUK. Antibodies to the 70 kDa antigen were related to the Wegener's granulomatosis rather than the PUK.

Adult↗
PubMed1992

The polar-lethal Ovum mutant gene maps to the distal portion of mouse chromosome 11.

Genome imprinting is the process by which identical alleles at a particular locus may be rendered functionally different depending on the sex of the parent contributing the allele. While several mutations in imprinted genes have been defined, no variants in the regulatory system that gives rise to imprinting have been described. Here we report our genetic analysis of the behavior of the interstrain, polar, embryonic-lethal phenotype known as the "DDK syndrome." We have mapped the interstrain, polar-lethal region of the genome to the distal portion of mouse chromosome 11, near the Xmv-42 locus. We propose that the lethal phenotype is not caused by a standard mutation, but by aberrant imprinting of a gene within this region.

Animals↗
PubMed1992

Monoclonal antibody epitopes of mycobacterial 65-kD heat-shock protein defined by epitope scanning.

The binding sites for MoAbs to the 65-kD heat-shock protein (hsp65) of mycobacteria have been investigated by epitope scanning. Five hundred and twenty-six 8-mer peptides representing the complete sequence of Mycobacterium tuberculosis hsp65 were synthesised in duplicate using the Epitope Scanning Kit (CRB Ltd.). The epitopes of six MoAbs raised to the hsp65 of M. tuberculosis or M. leprae were investigated. We have identified the epitope of a new MoAb (DC16); this epitope is continuous, hydrophilic in nature and 11 amino acids long. We have also confirmed the location of the epitopes of three MoAbs (IIH9, ML30 and IIC8). Thus the epitope scanning technique has proved suitable for the detection of continuous epitopes of hsp65.

Amino Acid Sequence↗
PubMed1992

The characterization of a mutation of the 3' flanking sequence of the alpha 1-antitrypsin gene commonly associated with chronic obstructive airways disease.

A restriction fragment length polymorphism (RFLP) of the 3' flanking region of the alpha 1-antitrypsin (AAT) gene, detected with the restriction enzyme TaqI, occurs in about 17% of patients with chronic obstructive airways disease (COAD). To characterize the mutation the sequence of this region of the normal AAT gene had to be determined. The sequence containing the site of the mutation was amplified by the polymerase chain reaction and the DNA was sequenced in six COAD patients. The mutation is a G to A transition and occurs in a region containing potential regulatory sequences corresponding to enhancer elements. It is as yet unclear if the mutation alters the expression of AAT.

Base Sequence↗
PubMed1992

Hypnotics, sleep, and mortality in elderly people.

OBJECTIVE: To re-assess relationships between mortality, hypnotic use, subjective insomnia, and sleep duration. DESIGN: A prospective study examining 5-year mortality among hypnotic drug users and respondents with subjective insomnia identified in a longitudinal study of health, activity, and lifestyle (Nottingham Longitudinal Study of Activity and Ageing). SETTING: General community. PARTICIPANTS: 1042 survey respondents, aged over 65 years, randomly selected from the community and stratified at age 75 years. MAIN OUTCOME MEASURE: Recorded mortality. RESULTS: During the 5-year period, 352 respondents died. The mortality rate was significantly greater among those taking some form of medication for sleep (n = 208) than for those not taking sleep medication (n = 812; chi-square = 4.91, df = 1, P = 0.027). When sleep medication users were categorized as either "hypnotic users" (ie, users of medication with recognized hypnotic or sedative actions) or "other users" (including analgesics and other over-the-counter medicines), only "other users" showed significant excess mortality (chi-square = 7.27, df = 1, P = 0.007). Logistic regression showed that "other users" were 2.5 times more likely to die than "non-users" even when gender, health risk, and usual sleep duration were controlled. There were no significant relationships between mortality and subjective insomnia or reported duration of sleep. CONCLUSIONS: Earlier reported relationships between excess mortality and use of medication for sleep are replicated in this study. Among elderly people, however, this relationship does not derive from the pharmacological characteristics of prescription hypnotics. Rather, it appears that reported self-medication to promote sleep, using a variety of non-sedative products, provides an epidemiological "marker" for a group within which levels of morbidity and mortality are particularly high. Excess mortality associated with very short or long sleep duration was not replicated in this study. Overall, these findings provide little epidemiological support for a wide-spread interaction between benzodiazepine hypnotic use and sleep disordered breathing in old age.

Aged↗
PubMed1992

Incidence of dementia: preliminary findings from the Nottingham Longitudinal Study of Activity and Ageing.

In a 4-year follow-up of 1,042 randomly sampled elderly people (aged 65+), levels of dementia were assessed using a two-phase case finding procedure (screening followed by clinical interview) among survivors. Clinical information on those not re-interviewed was provided by death certificates, hospital case notes or postal questionnaires. The unweighted 4-year cumulative incidence of dementia was 4.3%, with age-specific rates of 0.9, 2.8, 5.2, 9.0 and 8.7% for the age groups 65-69, 70-74, 75-79, 80-84, and 85-89, respectively.

Activities of Daily Living↗
PubMed1992

Identification of an immunodominant B-cell epitope in bovine type II collagen and the production of antibodies to type II collagen by immunization with a synthetic peptide representing this epitope.

Using epitope scanning of 272 short, synthetic peptides representing the amino acid sequence of the CB-11 peptide of type II collagen, we have shown that five strains of rat, immunized with type II collagen, produce antibodies to a region 37-45 amino acids from the amino end of CB-11 peptide. Antibodies to this region always gave the highest binding values suggesting that it is an immunodominant region. Wistar rats immunized with a synthetic peptide representing this region, coupled to keyhole limpet haemocyanin, produced antibodies to this peptide which could still be detected at 1:4000 to 1:8000 dilution but none developed clinical arthritis. All sera also showed binding of antibodies to denatured bovine type II collagen but not to native type II collagen, keyhole limpet haemocyanin or to bovine serum albumin by ELISA. Sera from peptide-immunized rats were examined for antibody binding to the 272 short peptides of the CB-11 peptide and to the synthetic peptides representing shortened forms of the immunodominant region and forms of it with substituted amino acids. These results showed that the antibodies in the peptide-immunized rats were not identical to those produced to that peptide by rats immunized with type II collagen but may represent subpopulations of them. These findings suggest caution in interpreting the role of antibodies to individual peptides in arthritis induction without knowledge of their fine specificity.

Animals↗
PubMed1992

[Genealogical study of oculopharyngeal dystrophy at Saguenay-Lac-St-Jean, Quebec, Canada].

The genealogies of 28 proband affected with oculopharyngeal dystrophy (OPD) distributed in 28 families from Saguenay-Lac-St-Jean, a geographically isolated region of northeastern Quebec, were reconstructed. The analysis of these genealogies showed that the Montmagny and L'Islet counties are the most likely center of diffusion of OPD among the French Canadians, as suggested by Barbeau in 1966. A unique founder couple, J.E.-M.B., common to all 28 genealogies was found. The children of this couple emigrated in the 17th century from Poitou (France), a region where several families with OPD were recently ascertained.

Blepharoptosis↗
PubMed1992

Atrial natriuretic factor in experimental cirrhosis in rats.

Atrial natriuretic factor (ANF) is a cardiac hormone with potent natriuretic, diuretic, and vasorelaxant properties. Although abnormalities in ANF release, plasma level, and renal receptors have been described in humans and/or animals with cirrhosis and ascites, little is known about the ANF hormonal system in cirrhosis without ascites. The aim of this study was to examine the ANF hormonal system in an animal model of cirrhosis to determine whether compensated cirrhosis is associated with changes in the ANF hormonal system. Pair-fed rats were studied 5-7 weeks after either sham surgery or bile duct ligation. Bile duct-ligated (BDL) rats had elevated portal pressure and cirrhosis but did not have ascites. ANF messenger RNA levels were increased onefold in the atria of BDL rats. Sham-operated and BDL rats had similar plasma ANF levels. Competitive binding inhibition studies of isolated glomeruli showed a single class of receptors in sham-operated and BDL rats. The equilibrium dissociation constant was similar in sham-operated (0.51 nmol/L) and BDL (0.63 nmol/L) rats. Glomerular ANF receptor density increased significantly in BDL rats. Cyclic guanosine monophosphate generation in isolated glomeruli in response to 100 nmol/L ANF decreased slightly but not significantly in BDL rats. It was concluded that the ANF hormonal system is altered in cirrhosis without ascites; atrial messenger RNA level and glomerular ANF receptor density are increased.

Animals↗
PubMed1992

Genetic analysis of 24 French families with multiple endocrine neoplasia type 2A.

The gene for multiple endocrine neoplasia type 2A (MEN2A) has been mapped to the pericentromeric region of chromosome 10 by linkage analysis. Thirty-four families with multiple cases of medullary carcinoma of the thyroid (MTC), including 24 families with origins in France, have been typed with nine polymorphic markers spanning the centromere of chromosome 10. No recombination was observed between the MEN2A locus and either of the four loci D10Z1 (lod score 12.79), D10S102 (lod score 6.38), D10S94 (lod score 7.76), and D10S34 (lod score 5.94). There was no evidence for genetic linkage heterogeneity in the panel of 34 families. Haplotypes were constructed for a total of 11 polymorphisms in the MEN2A region, for mutation-bearing chromosomes in 24 French families and for 100 spouse controls. One haplotype was present in four MEN2A families but was not observed in any control (P less than .01). Two additional families share a core segment of this haplotype near the MEN2A gene. It is likely that these six families have a common affected ancestor. Because the incidence of pheochromocytoma among carriers varies from 0% to 74% within these six families, it is probable that additional factors modify the expression of the MEN2A gene.

Adrenal Gland Neoplasms↗
PubMed1991

Normal values for weight, skeletal size and body mass indices in 890 men and women aged over 65 years.

Measurements of body weight and skeletal size have been made, as part of a demographically representative survey, in 532 women and 358 men aged over 65 years living in their own homes. Body weight was assessed using calibrated portable scales. Skeletal size was measured as half body span (demispan) using a steel tape stretched from the sternal notch to the finger roots. Age had a weak but significant negative association with both body weight and demispan. After controlling for demispan, age still accounted for a significant decline in weight (in kg per decade) of 2.5 in men and 3.5 in women. Weight, demispan and indices of weight-for-skeletal-size have been presented as percentiles for men and women separately.

Journal Article↗
PubMed1991

Genetic control of innate resistance to mycobacterial infections.

The Mendelian segregation of resistance to infection in different strains of mice infected with mycobacteria, Salmonella and Leishmania spp, all of which live in macrophages, is currently under close scrutiny. Here, Erwin Schurr and colleagues review the nature and function of the Bcg gene in controlling innate resistance to mycobacterial infection in mice and speculate on the occurrence of a possible human equivalent.

Animals↗
PubMed1991

Absence of autoimmunity to type II collagen in generalised nodal osteoarthritis.

A cardinal feature of generalised nodal osteoarthritis is the loss of articular cartilage. To determine if autoimmunity to these cartilage collagens occurred, serum antibodies to native and denatured type II collagen were measured by enzyme linked immunosorbent assay (ELISA) in 96 patients (90 women, six men, aged 47-91 years) with generalised nodal osteoarthritis. Generalised nodal osteoarthritis was diagnosed by typical clinical and radiological features. Serum samples from 42 blood donors were assayed as controls. No significant difference was found between the patients with generalised nodal osteoarthritis and the controls. Furthermore, the 20 patients who were HLA-A1, B8 positive had similar antibody levels to the group as a whole. One woman patient with generalised nodal osteoarthritis (HLA-A1, B8 negative) had markedly increased antibody levels to native and denatured type II collagen in a pattern similar to that seen in patients with rheumatoid arthritis. This patient did not develop super added rheumatoid arthritis during a three year follow up period. Autoimmunity to type II collagen is therefore rare in generalised nodal osteoarthritis. A lack of collagen antibodies in a condition characterised by hyaline cartilage loss suggests that the presence of such antibodies in rheumatoid arthritis is more than a secondary event to joint damage.

Aged↗