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Biomedical subjects

K Morgan

Publications and source records attributed to K Morgan.

At least 361 records · Page 20Linked to original sources
PubMed1978

Migration of human lymphocytes. I. A model using the mouse as host.

The distribution of radioactivity after the intravenous injection of 51Cr-labelled human lymphocytes has been examined in normal mice, irradiated mice, mice treated with anti-platelet antiserum and in mice treated with colloidal carbon. Pre-treatment with carbon and anti-platelet antiserum appears to protect the human lymphocytes from uptake by the host's reticuloendothelial system (RES). Comparison of tissue radioactivity in carbon-treated mice after the injection of viable human lymphocytes with that found after the injection of dead cells and soluble or insoluble cell debris showed that radioactivity recovered in the spleen and lymph nodes is primarily due to the migration of viable lymphocytes into these tissues. Thus the measurement of radioactivity in lymph nodes of carbon-treated mice after the injection of 51Cr-labelled human lymphocytes can be used as a model of these lymphocytes' ability to migrate into the lymph nodes during recirculation and to study factors influencing this migration.

Animals↗
PubMed1978

Migration of human lymphocytes. II. Variation of lymphocyte distribution.

Variations in the distribution of 51Cr-labelled human lymphocytes from several donors and from one donor on several occasions have been determined after their injection into carbon-treated mice and reasons for the variation discussed. Natural alteration of the lymphocyte surface (leukaemic lymphocytes) or induced change (trypsin-treatment) reduced lymph node localisation as did treatment with formalin, sodium azide and antilymphocyte globulin. We have concluded that the presence of radioactivity in the lymph nodes is due to the presence of viable, metabolically active lymphocytes with normal surfaces capable of interacting with the endothelium of the post-capillary venules.

Adult↗
PubMedDate not supplied

HLA class I, II & III genes in confirmed late-onset Alzheimer's disease.

We first examined all the then known alleles (1997) at the HLA-A, B, Bw, C, DRB1, 3, 4 and 5, and DQB1 loci in 55 late-onset (>65y) AD cases and 73 elderly controls from Oxford. We found an association of HLA-B7 with late-onset AD (odds ratio = 3.1, corrected P = 0.04) that was limited to apolipoprotein E epsilon4-negative subjects (odds ratio = 5.1, corrected P = 0.005). We then studied linkages with Class III genes and, finally, we sought to replicate our HLA-B7 result in cohorts from Montreal and Nottingham. Altogether, we used 299 histopathologically confirmed cases of late-onset AD and 175 controls. Our initial, clear finding was not replicated in Montreal and Nottingham, however. We also failed to support any other previously reported association of AD with an HLA gene. Though we cannot exclude distinct linkages in different cohorts as an explanation of the conflicting results of HLA/AD studies, we conclude that there is no compelling evidence of a strong, direct association between late-onset AD and any HLA Class I or II allele.

Aged↗
PubMedDate not supplied

Genetic mapping of X-linked loci involved in skewing of X chromosome inactivation in the human.

We have analyzed X-chromosome inactivation patterns in lymphocytes of 264 females from 38 families not known to have any genetic disease. Quantitative measures of X-inactivation showed strong sister-sister correlation in the degree of departure from equal numbers of cells having each X chromosome active, suggesting heritability of this phenotype. Strong sister-sister correlation was also observed for the fraction of cells having the same parent's X chromosome active, consistent with the possibility that this trait might be controlled by a cis-acting, X-linked gene. We used a sib-pair approach to determine whether X-inactivation phenotype was linked to loci in any region of the X chromosome. Both quantitative and discrete measures of X-inactivation phenotype showed evidence of linkage to markers in the region of the X inactivation center (XIC). The quantitative measure of X-inactivation phenotype used in our study also showed linkage to loci at Xq25-q26. This study provides the first evidence for X-linked inheritance of X chromosome inactivation phenotype derived from linkage analysis in phenotypically normal human families.

Base Sequence↗
PubMedDate not supplied

Normal values for range of shoulder abduction in men and women aged over 65 years.

The range of movement of the shoulder in abduction at 45 degrees of flexion was objectively measured using a standard technique in a demographically representative survey of 1000 men and women living in their own homes. Sampling was stratified to obtain approximately equal numbers of those aged 65-74 years and those aged 75 and over. The response rate was 80%. Normal values for shoulder abduction grouped by age and sex are presented as frequency distributions, means and deciles. Information about health problems was also recorded in the survey; the prevalences of these problems and their associations with shoulder abduction have been investigated. Women had significantly lower values for shoulder abduction than men. For both sexes values were on average about 30 degrees lower than those found in younger adults, and about half of the elderly group had values below 120 degrees. The prevalence of specified health problems was high with only 3% of the older group and 6% of the younger group being free from all the specified health problems. There was a significant independent negative association between shoulder abduction and both age and reported health. The associations were more marked in women than in men. This was so for both a cumulated 14-item health index and selected individual health items which included arthritis, lack of mobility and incontinence. The decile values for shoulder abduction for women without these health problems are presented. This provides more appropriate normal data for them; it is more normally distributed and reduces the percentage with a shoulder abduction less than 120 degrees to 30%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Protein catabolic rate in patients on continuous peritoneal dialysis. A multivariate predictive model.

Protein catabolic rate (PCR) and PCR normalized to standard weight (PCRN) are important indices of nutrition in patients on continuous peritoneal dialysis. The purpose of this study was to test whether urea clearance is among the predictors of PCR and PCRN in a multivariate analysis. Stepwise logistic regression was used to develop separate models for low PCR and low PCRN on a set of 143 urea kinetic studies in 92 patients on continuous peritoneal dialysis. The regression models were tested on an independent sample of 189 urea kinetic studies in 102 patients on continuous peritoneal dialysis by deriving the area under a receiver operating characteristic curve. In the derivation set, low serum urea, high serum creatinine, low urine and dialysate drain volumes, and low body surface area were identified as predictors of PCR < or = 50 g daily. The area under the receiver operating characteristic curve in the validation set was 0.930 (95% confidence interval: 0.915-0.945). Low serum urea, male gender, high body mass index and low urea fractional clearance (KT/V) were predictors of PCRN < or = 0.80 g/kg daily. The receiver operating characteristic area for this model was 0.948 (95% confidence interval: 0.926-0.970). Logistic regression analysis was repeated twice after adding urea nitrogen excretion normalized to standard weight (UNEN) as a candidate variable. This process identified low UNEN, male gender, and obesity as the predictors of low PCRN, and low UNEN, male gender, low urine volume, low drain volume normalized by body water, and high serum albumin as predictors of low KT/V urea. The authors conclude that PCR and PCRN can be predicted by models that incorporate serum azotemic indices, body size and composition, and direct or indirect measurements of urea clearance. Small body size and lean body composition predict low PCR but high PCRN values. Both PCRN and KT/V urea are predicted by UNEN. Multivariate analysis cannot, therefore, rule out the hypothesis that PCRN and KT/V are linked mathematically.

Body Weight↗
PubMedDate not supplied

Type II collagen induced arthritis: comparison of histological changes in arthritis-susceptible and arthritis-resistant rats.

Wistar rats (type II collagen-induced arthritis-susceptible) and PVG.RT1u rats (arthritis-resistant) were immunised with type II collagen and histological changes in the synovial tissues of the hind feet and in the popliteal lymph nodes draining these feet were examined and compared with unimmunised rats. There were no apparent differences in the joints of unimmunised rats of each strain, but the popliteal lymph nodes of the Wistar rats appeared more "activated", suggesting possible differences between strains in the continuous, low-grade release of antigens from the joints. Whilst the joints of arthritic rats showed the most marked histological changes, the joints of immunised PVG.RT1u rats and of non-arthritic Wistar rats showed some minor changes in the synovia and loss of cartilage with a concomitant increase in the size of the popliteal lymph nodes. The number of mast cells per unit area increased in the lymph nodes of immunised PVG.RT1u rats in proportion to the size increase, but decreased in those draining arthritic Wistar rat feet. The number of mast cells per unit area of synovium decreased most in arthritic feet and the staining pattern of the mast cells altered in the most severely arthritic feet, suggesting a change in mast cell population. These differences in mast cells may be directly related to whether or not clinical arthritis develops in a particular joint. Further study of mast cell sub-populations is warranted.

Animals↗
PubMedDate not supplied

Diversity of the immune response to bovine type II and XI collagens in rats.

Immunisation of rats with native type II or type XI collagen produced an inflammatory arthritis in certain strains of rats. Antibodies to the native and denatured whole molecules, to the individual alpha chains and to the cyanogen bromide derived peptides of these chains were studied. Inter- and intra-strain variation in the specificity of the antibodies produced was seen and there were also changes with time, especially with the rats immunised with type XI collagen. Both collagen type-specific and cross-reacting antibodies were produced following immunisation with either type II or type XI collagen. Although no specific pattern of antibodies was unique to the presence or absence of arthritis in all rats, antibodies that bound to the CB-11 peptide or antibodies that bound to the CB-9,7 peptide of type II collagen occurred at the time of onset of arthritis in type II or type XI immunised, arthritic rats. Antibodies to these peptides occur in many patients with rheumatoid arthritis (RA) who also have antibodies to type II collagen. Therefore these findings suggest that epitopes on these peptides may be important in the continued production of antibodies to these collagens in patients with RA and that these antibodies may indeed be pathogenic.

Animals↗
PubMedDate not supplied

Independent mutations in the flanking sequence of the alpha-1-antitrypsin gene are associated with chronic obstructive airways disease.

Two restriction fragment length polymorphisms (RFLPs) of the flanking sequence of the alpha 1-antitrypsin (AAT) gene, detected with the restriction enzymes HindIII and TaqI, have been reported to occur more commonly in patients with chronic obstructive airways disease (COAD). Their frequencies were investigated in 20 Caucasian families with a family history of COAD and in 140 unrelated COAD patients none of whom had AAT deficiency. The HindIII polymorphism was present in six index cases of 20 families (p = 0.0015) and 14 of the unrelated patients (p = 0.061) compared with one of 60 healthy unrelated controls. The TaqI polymorphism was present in five of 101 healthy unrelated controls and in three index cases of the 20 families. In the unrelated patient group 28 of 140 had the polymorphism (chi 2 = 10.01, p = 0.0016) and corresponds to a mean log odds ratio of 1.56 (95 per cent confidence limits of 0.58-2.56). The polymorphisms occurred independently of each other and were not associated with AAT deficiency in the basal state.

Adolescent↗