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Biomedical subjects

A H Little

Publications and source records attributed to A H Little.

18 recordsLinked to original sources
PubMed1994

Investigating the genetic basis for ankylosing spondylitis. Linkage studies with the major histocompatibility complex region.

OBJECTIVE: To assess the hypothesis that B27 or a gene(s) in close proximity (e.g., within or near the major histocompatibility complex [MHC]) represents a disease-causing ankylosing spondylitis (AS) gene, and therefore contributes directly to the pathogenesis of this disorder. METHODS: MHC haplotypes were determined by both serologic and molecular analyses in 15 multiple-case AS families from Toronto and Newfoundland. Segregation of MHC haplotypes with AS within these families was examined by linkage and identity-by-descent analyses. Attributable risk estimates for various genetic markers and for sex were calculated. RESULTS: Linkage analyses established significant linkage between AS and the MHC, the maximal logarithm of odds (LOD) score being 3.48 at a recombination frequency (O) of 0.05. In a second analysis in which the population association of the MHC gene HLA-B27 with AS was taken into account, the maximal LOD score was 7.5 at O = 0.05. Identity-by-descent analyses showed a significant departure from random segregation among affected avuncular (P < 0.05) and cousin (P < 0.01) pairs. The presence of HLA-B40 in HLA-B27 positive individuals increased the risk for disease more than 3-fold, confirming previous reports. Disease susceptibility modeling suggested an autosomal dominant pattern of inheritance, with penetrance of approximately 20%. CONCLUSION: These data provide the first conclusive demonstration of linkage between the MHC region and AS, and confirm that genes within this region contribute directly to the genetic susceptibility for AS.

Adolescent↗
PubMed1984

Classical conditioning and retention of the infant's eyelid response: effects of age and interstimulus interval.

Independent groups of 10-,20-, and 30-day-old infants were subjected to a classical eyelid conditioning procedure involving either a 500- or a 1500-msec interstimulus interval (ISI). Ten days later, all received a second conditioning session. A reliable increase in conditioned responding was observed at all ages but only by infants receiving the 1500-msec ISI. Although age was not a significant factor in any conditioning measure except final performance level, which was greater for the oldest than for the youngest group, it did influence long-term retention. A reliable memory component was observed in the Session 2 performance of infants initially trained at 20 and 30 days but not at 10 days. These data demonstrate the importance of temporal parameters in the formation of conditioned associations very early in infancy and provide evidence for the long-term behavioral consequences of those associations.

Acoustic Stimulation↗
PubMed1983

Lymphomatoid granulomatosis involving the gastrointestinal tract. Two case reports and a review of the literature.

Two cases of lymphomatoid granulomatosis affecting the gastrointestinal tract in the form of gastric ulceration and intestinal perforation are described. This rare presentation of lymphomatoid granulomatosis is discussed in the context of previous reviews of the disease, and it is suggested that clinically overt gastrointestinal involvement represents a very poor prognostic indicator in this condition.

Adult↗
PubMed1983

Stress fractures in rheumatoid arthritis.

Four cases of rheumatoid arthritis with a total of 12 undisplaced stress fractures of the lower extremities are described. Pain, swelling and disability arising from these fractures were initially mistaken for rheumatoid synovitis. Three patients had osteoporosis, and one had osteomalacia. A high index of suspicion is necessary in the diagnosis of these fractures. Radiographs and, if necessary, bone scans are indicated in rheumatoid patients presenting with spontaneous pain in the lower extremities in association with tenderness localized over the bone rather than the joint, particularly in the absence of other signs of rheumatoid activity.

Aged↗
PubMed1981

Clinical and roentgenographic aspects of pseudogout: a study of 50 cases and a review.

Pseudogout, defined as recurrent acute arthritis due to intrasynovial deposition of calcium pyrophosphate dihydrate crystals, is a relatively common arthritic disorder of the elderly. The clinical and roentgenographic aspects of 50 cases of pseudogout in hospitalized patients are reviewed in this paper. Oligoarticular and polyarticular episodes were observed in half of these patients. Antecedent problems included infection, trauma, surgery and vascular events. Consistent with previous reports, most patients had roentgenographic evidence of chondrocalcinosis. A third had asymptomatic capsular or periarticular calcific deposits or both, and a third had pyrophosphate arthropathy, a progressive, destructive, accelerated form of osteoarthritis. An attack of pseudogout may offer a clue to the presence of an unsuspected metabolic disease, such as primary hyperparathyroidism or idiopathic hemochromatosis.

Age Factors↗
PubMed1980

Ankylosing spondylitis: survival in men with and without radiotherapy.

We investigated survival of a group of 151 Canadian war veterans with ankylosing spondylitis who were entered into a prospective study in 1947-1949. With 94% successful followup, total survival was 60.9%, significantly less than expected. However, a subgroup who had not been treated with radiotherapy had a survival not significantly different from the general population. Causes of death in both irradiated and nonirradiated subgroups were determined.

Adult↗
PubMed1976

Sacroiliitis in severe psoriasis.

In 100 consecutive patients admitted to the hospital for control of severe psoriasis, 25 had radiologic changes characteristic of psoriatic arthritis. Twenty had erosions and mild sclerosis around the sacroiliac joint; in eight of these, asymptomatic sacroiliac changes were the sole manifestation of musculoskeletal disease. Twelve had vertebral syndesmophytes, 11 had terminal interphalangeal joint changes, and 10 had peripheral joint involvement.

Adult↗
PubMed1975

Bone growth kinetics IV: a preliminary investigation on a biorhythm in human osteogenesis.

Multiple doses of oxytetracycline were administered at regular but different intervals to groups of patients undergoin orthopaedic surgery. It was found that doses of the drug were incorporated at bone growth sites most frequently if the intervals between those doses were 3 or 6 days. This suggests a biorhythm in human bone growth with a periodicity of 3 days: this biorhythm may be altered by hormones or drugs.

Adult↗
PubMedDate not supplied

Apatite-associated arthropathy: a clinical study of 14 cases and of 2 patients with calcific bursitis.

Fourteen cases of acute calcific periarthritis and 2 cases of acute calcific bursitis are described. All patients had radiologic periarticular calcific deposits. Synovial fluid was available from 8 patients. Hydroxyapatite crystals were positively identified in 1 by x-ray diffraction analysis and by scanning and transmission electron microscopy. Apatite-associated arthropathy likely represents a form of crystal-induced inflammation. Three articular syndromes can be recognized; acute calcific periarthritis, acute (calcific) arthritis and a subacute-to-chronic arthritis resembling osteoarthritis. To improve patient classification, diagnostic criteria are proposed.

Acute Disease↗
PubMedDate not supplied

Coexistence of rheumatoid arthritis in married couples: a search for etiological factors.

Epstein-Barr virus (EBV) and the genetic marker HLA-DR4 both appear to play a role in the etiology of rheumatoid arthritis (RA). Antibodies to viral capsid antigen and the early antigen complex of the EB virus as well as the HLA phenotype were studied in 6 families. Both spouses had classical or definite RA but none of their offspring, all adult, had any evidence of RA. At least 1 spouse of each couple had DR4 and this phenotype was found in 4 of the 8 offspring. All parents and their offspring had been infected with EBV. This study supports the association of DR4 and RA. The presence of DR4 in 4 normal adult offspring was not associated with the absence of primary infection or enhanced levels of EBV-specific antibodies.

Adult↗
PubMedDate not supplied

Cholesterol crystals in osteoarthritic joint effusions.

Cholesterol crystals were demonstrated in synovial fluids from 4 patients with knee osteoarthritis and recurrent synovial effusions. Large crystals (10-80 micros) were readily identifiable by their characteristic plate-like morphology. Some fluids also contained numerous smaller (1-5 microns) irregular, rod and needle shaped crystals. Identification of these crystals as cholesterol was established by x-ray diffraction analysis (2 fluids) and by ultrastructural studies (1 fluid). This study documents the occurrence of cholesterol crystals in osteoarthritic effusions, but their precise pathogenetic significance remains unclear.

Adult↗