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Biomedical subjects

R G Palmer

Publications and source records attributed to R G Palmer.

At least 19 recordsLinked to original sources
PubMed2001

Oxalate content of soybean seeds (Glycine max: Leguminosae), soyfoods, and other edible legumes.

Consumption of soybeans and food products made from them is increasing because of their desirable nutritional value. However, the oxalate content of seeds from 11 cultivars of soybean showed relatively high levels of total oxalate from 0.67 to 3.5 g/100 g of dry weight. Oxalate primarily was found as calcium oxalate crystals. Thirteen tested commercial soyfoods contained between 16 and 638 mg of total oxalate per serving. These values compare to those of three other legume foods, peanut butter, refried beans, and lentils, which contained 197, 193, and 100 mg of total oxalate per serving, respectively. After oxalate has been absorbed from the diet, it cannot be metabolized and is excreted by the kidney into urine, where it binds to calcium forming an insoluble salt that may precipitate to form kidney stones. The amounts of total oxalate in soybean seeds, soy foods, and other common legume foods exceed current recommendations for oxalate consumption by individuals who have a history of calcium oxalate kidney/urinary stones. This study serves as the basis to find soybean cultivars lower in oxalate, which will have lower risk for kidney stone formation after human consumption.

Calcium Oxalate↗
PubMed1999

Analysis and mapping of gene families encoding beta-1,3-glucanases of soybean.

Oligonucleotide primers designed for conserved sequences from coding regions of beta-1,3-glucanase genes from different species were used to amplify related sequences from soybean [Glycine max (L.) Merr.]. Sequencing and cross-hybridization of amplification products indicated that at least 12 classes of beta-1,3-glucanase genes exist in the soybean. Members of classes mapped to 34 loci on five different linkage groups using an F(2) population of 56 individuals. beta-1,3-Glucanase genes are clustered onto regions of five linkage groups. Data suggest that more closely related genes are clustered together on one linkage group or on duplicated regions of linkage groups. Northern blot analyses performed on total RNA from root, stem, leaf, pod, flower bud, and hypocotyl using DNA probes for the different classes of beta-1,3-glucanase genes revealed that the mRNA levels of all classes were low in young leaves. SGlu2, SGlu4, SGlu7, and SGlu12 mRNA were highly accumulated in young roots and hypocotyls. SGlu7 mRNA also accumulated in pods and flower buds.

Amino Acid Sequence↗
PubMed1999

Behçet's syndrome: a multidisciplinary approach to clinical care.

Behçet's syndrome is a multisystem disorder characterized by recurrent orogenital ulceration and an occlusive vasculitis. Histologically, there is a combination of a perivascular lymphocytic infiltration with endothelial cell damage coupled with a pro-thrombotic tendency. We present a multidisciplinary approach to the management of Behçet's syndrome, and compare our findings with other published studies. Over a nine-year period, 50 patients with Behçet's syndrome were followed in a multidisciplinary combined clinic. Patients were assessed by an ophthalmologist, a rheumatologist and a specialist in oral medicine. Data on disease activity and damage were collected using a standardized proforma for each specialty. Mean age of onset was 30 years; 56% were male. Recurrent oral ulceration was the commonest manifestation and the presenting feature in 76%. The commonest second systems involved were genital mucosae and eyes. We found a larger proportion of patients with ophthalmic (80%) and central nervous system (14%) manifestations compared with many other studies. There was an association between central nervous system and thrombotic events (p<0.001). Our multidisciplinary approach allowed us to keep each system involved in Behçet's syndrome under careful review. The development of recurrent sight-threatening eye disease was unpredictable and occurred despite aggressive immunosuppression.

Adolescent↗
PubMed1998

Instability at the k2 Mdh1-n y20 chromosomal region in soybean.

Ten mutants have been reported at the k2 (tan saddle seed coat) Mdh1-n (mitochondrial malate dehydrogenase 1 null) y20 (yellow foliage) chromosomal region in soybean [Glycine max (L.) Merr.]. The precise genetic mechanism(s) responsible for generating these mutants is (are) not known. The objective of this study was to determine whether chromosomal instability exists at this region. We introduced the w4-m and Y18-m mutable systems into the three independent sources of tan saddle seed coat mutants, T239 (k2), T261 (k2 Mdh1-n), and L67-3483 (k2). A total of 12 bright yellow mutants were isolated with tan saddle seed coat, malate dehydrogenase 1 null phenotypes. Of these, 11 were found in 11 F2 mutant families out of a total of 977 derived by crossing T239 (k2), T261 (k2 Mdh1-n), and L67-3483 (k2) with six lines suspected to contain active transposable elements. One was found in the F3 generation derived from the cross A1937 x T239 (k2). Of the 11 F2 mutant families, 10 (out of a total of 381 F2 families) were associated with the T239 (k2) genetic background, and one out of 323 was associated with the T261 (k2 Mdh1-n) genetic background. But no mutation events were found among the 273 families with the L67-3483 (k2) genetic background. Allelism and inheritance studies indicated that these 12 bright yellow mutants were new mutants in the k2 Mdh1-n y20 chromosomal region. Thus, on introducing the w4-m and Y18-m mutable systems into T239 (k2) and T261 (k2 Mdh1-n) genetic backgrounds, chromosomal instability was induced in this region. In addition, 21 greenish yellow mutants were identified in the total of 977 F2 families. All 21 greenish yellow mutants were associated with the T239 (k2) genetic background. The mutations for greenish yellow foliage affected foliage color only at the seedling stage. Cosegregation of the tan saddle seed coat character with greenish yellow foliage were observed for these 21 greenish yellow mutants, suggesting that the greenish yellow phenotype may be due to a pleiotropic effect of the k2 allele in T239 or to chromosomal rearrangements at or near the k2 allele in T239. Finally, we believe that the genetic mechanism responsible for this high frequency of instability at the k2 Mdh1-n y20 chromosomal region involves receptor element activities present at this chromosomal region, which may contain complex chromosomal rearrangements in T239 and T261.

Chromosome Breakage↗
PubMed1997

Programmed cell death in the root cortex of soybean root necrosis mutants.

The soybean root necrosis (rn) mutation causes a progressive browning of the root soon after germination that is associated with accumulation of phytoalexins and pathogenesis-related proteins and an increased tolerance to root-borne infection by the fungal pathogen, Phytophthora sojae. Grafting and decapitation experiments indicate that the rn phenotype is root-autonomous at the macroscopic level. However, the onset and severity of browning was modulated in intact plants by exposure to light, as was the extent of lateral root formation, suggesting that both lateral roots and the rn phenotype could be directly or indirectly controlled by similar shoot-derived factors. Browning first occurs in differentiated inner cortical cells adjacent to the stele and is preceded by a wave of autofluorescence that emanates from cortical cells opposite the xylem poles and spreads across the cortex. Before any visible changes in autofluorescence or browning, fragmented DNA was detected by TUNEL (Terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling) in small clusters of inner cortical cells that subsequently could be distinguished cytologically from neighboring cells throughout rn root development. Inner cortical cells overlying lateral root primordia in either Rn or rn plants also were stained by TUNEL. Features commonly observed in animal cell apoptosis were confirmed by electron microscopy but, surprisingly, cells with a necrotic morphology were detected alongside apoptotic cells in the cortex of rn roots when TUNEL-positive cells were first observed. The two morphologies may represent different stages of a common pathway for programmed cell death (pcd) in plant roots, or two separate pathways of pcd could be involved. The phenotype of rn plants suggests that the Rn gene could either negatively regulate cortical cell death or be required for cortical cell survival. The possibility of a mechanistic link between cortical cell death in rn plants and during lateral root emergence is discussed.

Apoptosis↗
PubMed1995

The prevalence and incidence of systemic lupus erythematosus in Birmingham, England. Relationship to ethnicity and country of birth.

OBJECTIVE: To establish the point prevalence of systemic lupus erythematosus (SLE) on January 1, 1992, and the incidence of SLE during 1991, in Birmingham, England, a large city with a broad ethnic mix. METHODS: Six sources were used to ascertain patients with diagnosed SLE, including notification by attending and primary care physicians, the lupus patient support group, and hospital inpatient and laboratory data. RESULTS: There were 242 SLE patients (227 females, 15 males) identified: prevalence rate 27.7/100,000 (95% confidence interval 24.2-31.2/100,000) in the population and 206.0/100,000 in Afro-Caribbean females. No significant differences in female ethnic prevalence rates by place of birth were observed. Thirty-three patients developed SLE in 1991: incidence rate 3.8/100,000/year (95% confidence interval 2.5-5.1/100,000/year). CONCLUSION: This study illustrates dramatic differences in incidence and prevalence rates in the UK, depending on ethnic group and irrespective of place of birth.

Adolescent↗
PubMed1994

Cumulative effects model: a response to Williams (1994)

The cumulative effects (CE) model explains free-operant choice by the ratio of total numbers of responses and reinforcements, a probability-like variable. Williams (1994) argues that the model is vulnerable to experiments that disprove melioration, a local probability model. The authors note critical differences between the nonlocal CE model and local probability models that allow the CE model to handle some data with which they are incompatible. All models are simplifications of reality; hence, a model's failures are as revealing as its successes. Williams suggests that simple models may need to be abandoned in favor of a "representational" account. The authors point out that representations must be both acquired and acted on. Acquisition requires processing of responses and reinforcers; action requires decision rules. Models are simply testable suggestions for what these rules and processes might be.

Behavior Therapy↗
PubMed1994

Cross-sectional analysis of the differences between patients with systemic lupus erythematosus in England, Brazil and Sweden.

This study is a cross-sectional analysis of the differences between SLE outpatients seen in Rheumatology departments at University centres in England, Brazil and Sweden, using a standard protocol. The demographic characteristics, extent and activity of disease of 209 patients with SLE were studied; 112 patients were seen in England, 33 in Brazil and 64 in Sweden. The median age of disease onset of Brazilian and English patients was 25 years and of Swedish patients 31.5 years. Disease activity was measured by the BILAG index. In most systems Brazilian patients experienced more activity than English patients and English patients more activity than Swedish patients. Non-Caucasians experienced more active disease than Caucasians. No sex or occupational differences were observed in disease activity. English patients were the most likely to have experienced photosensitivity, oral ulcers and haematological disorders, Brazilian patients renal disorders and Swedish patients discoid rashes. Brazilian patients were the most likely to be prescribed only one drug for treatment of SLE and to be taking steroids and the highest dose of steroids, in contrast to the European patients who were often prescribed steroids and an antimalarial agent or azathioprine. The results of this cross-sectional assessment of disease activity using a standardized instrument indicate that there are real differences in the extent and degree of activity of SLE in different national groups. This reflects a combination of genetic, environmental and social influences on disease expression and has implications for treatment and monitoring of SLE patients.

Adolescent↗
PubMed1993

The process of recurrent choice.

Recurrent choice has been studied for many years. A static law, matching, has been established, but there is no consensus on the underlying dynamic process. The authors distinguish between dynamic models in which the model state is identified with directly measurable behavioral properties (performance models) and models in which the relation between behavior and state is indirect (state models). Most popular dynamic choice models are local, performance models. The authors show that behavior in different types of discrimination-reversal experiments and in extinction is not explained by 2 versions of a popular local model and that the nonlocal cumulative-effects model is consistent with matching and that it can duplicate the major properties of recurrent choice in a set of discrimination-reversal experiments. The model can also duplicate results from several other experiments on extinction after complex discrimination training.

Animals↗
PubMed1993

Cardiac and systemic complications in multicentric reticulohistiocytosis.

A 75-year-old man with a short history of cutaneous lesions of multicentric reticulohistiocytosis, preceded by a few months of a symmetrical polyarthritis is described. Within 5 months of onset of symptoms, he developed congestive cardiac failure secondary to pericardial involvement by the disease and succumbed despite therapy with cyclophosphamide and methylprednisolone. Post-mortem revealed the true extent of the disease, with nodules seen in the epiglottis and aryepiglottic folds, duodenal mesentery, pleura, pericardium and myocardium. Although the hallmarks of the disease are the papulonodular skin lesions, together with a severe, sometimes mutilating polyarthropathy, its widespread systemic nature is not often appreciated. We review five other cases in the literature with pericardial involvement and discuss aids to earlier diagnosis by synovial fluid cytology; gallium scanning is discussed as a potentially useful means of detecting the extent of systemic involvement in multicentric reticulohistiocytosis.

Aged↗
PubMed1992

Inheritance of malate dehydrogenase nulls in soybean.

Three chlorophyll-deficient mutants (CD-1, CD-2, and CD-3), derived from the progeny of independent germinal revertants from the w4-mutable soybean line [Glycine max (L.) Merrill], were characterized genetically. Electrophoretic analyses indicated that these lines lacked two of three mitochondrial malate dehydrogenase isozymes (MDH-). The absence of two MDH bands was conditioned by a recessive allele at a locus designated Mdh1. All three CDs were allelic to each other and to T253, a Harosoy isoline y20-k2 MDH- from the Genetic Type Collection. The MDH- phenotype and the yellow-green plant phenotype were each inherited as single recessive alleles. No recombination between the two traits was found in nine F2 populations from crosses of the CDs by wild-type soybean lines. Complete linkage of the Mdh1 and y20 loci suggested that the mutations in the chlorophyll-deficient lines were deletions. Phenotypic differences among the CDs suggested that the deletions may have different endpoints. The chromosomal aberrations were not large enough to affect transmission of y20 and Mdh1 mutant alleles through the pollen or ovule. CD-1, CD-2, and CD-3 were added to the Soybean Genetic Type Collection as T323, T324, and T325, respectively.

Alleles↗
PubMed1992

Polyclonal origin of rheumatoid synovial T-lymphocytes.

Nineteen T-cell clones from seven patients with RA were obtained by cloning infiltrating lymphocytes from needle synovial biopsies. Southern blot analysis of the T-cell receptor (TCR) beta-chain genes in these clones revealed that there were no T-cell clones with an identical rearrangement of the TCR beta gene. These results do not support the idea that the infiltrating T-lymphocytes in RA are of monoclonal or oligoclonal origin.

Arthritis, Rheumatoid↗
PubMed1992

Questionnaire study of the use of surgical shoes prescribed in a rheumatology outpatient clinic.

Our questionnaire study was undertaken to ascertain the proportion of patients who use an appliance and to what extent, up to a year after being prescribed. Twenty-four percent no longer used the appliance. Two-thirds wore their orthosis for more than 6 hours/day. Half the patients had surgical shoes--moulded and bespoke, most found their shoes of benefit. Moulded shoes were found to be worn more frequently and to be more comfortable, easier to put on and more attractive. Patients reported a significantly greater improvement in their condition with moulded shoes than with bespoke shoes.

Adult↗
PubMed1991

Panniculitis: a report of four cases and literature review.

Panniculitis is a disease with many causes and associations. The classification of clinical subtypes is unsatisfactory and hampered by the use of eponyms. Four children with recurring panniculitis are described and their histology presented. Three had subcutaneous fat atrophy with lobular panniculitis on biopsy; all responded well to corticosteroids. The fourth child had a septal panniculitis with no atrophy of subcutaneous tissues and only a partial response to treatment with corticosteroids. A widely accepted precise histological classification of panniculitis is needed to enable accurate predictions of the outcome of this serious disorder.

Adipose Tissue↗
PubMed1990

Azathioprine, cyclophosphamide and chlorambucil.

Immunosuppressive agents serve a major role in the management of once-fatal conditions such as the systemic necrotizing vasculitides, but they are also being used in more common, chronic inflammatory disorders such as rheumatoid arthritis. The drugs are all capable of reducing cell division but they differ in their modes of action. This is in keeping with their differing rates of action, and different indications. Azathioprine is a valuable alternative to slow-acting antirheumatic drugs in older patients with rheumatoid arthritis. Cyclophosphamide has transformed the outlook of many forms of vasculitis. Chlorambucil is particularly useful in improving the prognosis for children with amyloidosis secondary to juvenile chronic arthritis. We have tried to highlight the role of these drugs in a number of rheumatic diseases. We have emphasized their clinical applications, with some laboratory evidence for their effects. The major side-effects are reviewed. Finally, we have discussed their possible mechanisms of action.

Arthritis, Rheumatoid↗
PubMed1989

Herpes simplex virus and the rheumatic diseases.

A viral aetiology for rheumatoid arthritis and inflammatory connective tissue diseases has been sought in general terms first, by studying viral growth patterns in lymphocytes from the blood and lesions of patients affected second, by analysing lymphocyte concentrations of the interferon-induced enzyme 2-5 oligo-adenylate synthetase (2-5 A); and third, by probing Southern blots of lymphocyte DNA with viral probes. Indirect evidence consistent with a viral aetiology has been found in several such diseases, but direct proof has been difficult to adduce. There is some suggestion that herpes simplex viral (HSV) DNA is present in Behcet's blood lymphocytes, but the findings are inconsistent. It is also plausible that viruses such as HSV do not induce these diseases through classic immunopathological mechanisms, but as "promoters" of abnormal lymphoproliferation in individuals with predisposing defects, possibly related to selective DNA repair defects.

Behcet Syndrome↗