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Biomedical subjects

A Young

Publications and source records attributed to A Young.

At least 343 records · Page 19Linked to original sources

Stress fractures of the lower limb in patients with rheumatoid arthritis.

Thirteen patients suffering from rheumatoid arthritis had 19 stress fractures of the tibia or fibula. These patients characteristically presented with sudden, severe, unexplained pain with localised tenderness just below the knee or above the ankle. In seven patients examination of the adjacent joint indicated a flare-up of disease activity or a pyogenic arthritis. In six patients the diagnosis was delayed by the late appearance of callus in minute fractures. All patients had rheumatoid deformities of the ipsilateral lower limb: valgus deformities of the knee and subtalar joints occurred most frequently. All patients had osteoporosis; all except two had received steroid treatment and five had abnormalities of calcium metabolism. We suggest that deformities of the knee and ankle predispose patients with rheumatoid arthritis and osteoporosis to stress fractures of the tibia and fibula.

Adult↗

The gay report on sexually transmitted diseases.

Most studies of sexually transmitted diseases in homosexual men have examined prevalence in clinic populations; for comparative purposes, we analyzed data from a survey of 4,329 gay men conducted in 1977. Among 4,212 respondents to the self-administered questionnaire, 66.8 per cent reported previous infection with pediculosis; 38.4 per cent, gonorrhea; 24.1 per cent, nonspecific urethritis; 18.1 per cent, venereal warts; 13.5 per cent, syphilis; 9.7 per cent, hepatitis; and 9.4 per cent, herpes. Number of different lifetime sexual partners best predicted histories of symphilis (r = .249), gonorrhea (r = .402), and the other diseases; frequency of checkups, years as a practicing homosexual, and furtive sexual activities were among the many other significant correlates of venereal infections. Respondents most often sought examinations from private physicians (39.4 per cent); those who visited gay clinics were examined most often and felt most positive about their medical care. Gay men who participated in the survey reported frequent infections with many of the same sexually transmitted diseases often seen in private medical practices, public VD clinics, and gay health centers. Since high rates of disease are related to large numbers of different partners, frequent exposures with anonymous contacts, and anal intercourse, we recommend frequent examinations for those whose life-styles include these characteristics.

Hepatitis B↗

Increased incidence of faecal Klebsiella pneumoniae in patients with HLA B7 CREG antigen and men with rheumatoid arthritis.

In a study of the carriage of faecal Klebsiella pneumoniae in 106 patients with rheumatoid arthritis the incidence of carriage was higher in men (28%) than women (14%) (p < 0.001) and klebsiellae were isolated on two or more occasions from a higher proportion of men than women (p < 0.002). The incidence of carriage was increased among patients with rheumatoid arthritis who had B7 cross-reacting (B7 CREG) antigens (32% v 13%--p < 0.001). Carriage of klebsiellae was not associated with clinical disease activity, raised erythrocyte sedimentation rate, drug treatment, or the presence of HLA Dw4 or DRw4 or both. Thus the carriage and prevalence of faecal Klebsiella pneumoniae appear to be partly determined by the sex and HLA state of the host.

Arthritis, Rheumatoid↗

The clinical assessment of joint inflammatory activity in rheumatoid arthritis related to radiological progression.

A simple clinical method for the assessment of joint disease activity is described, and analysed with respect to radiological progression of erosive disease. Ninety-four patients with rheumatoid arthritis attending a special research clinic as part of a prospective study were studied over a three-year period. A significant correlation was found between clinical activity, assessed at intervals of four months, and progressive erosive disease but not with juxta-articular osteoporosis. This clinical method compares favourably with a modification of the articular index described by the Cooperating Clinics of North America.

Arthritis, Rheumatoid↗

BK virus DNA sequence coding for the t and T antigens and evaluation of methods for determining sequence homology.

The DNA sequence of the early region of the human papovavirus BK (MM strain) was determined. A potential initiation signal for translation is located at nucleotides 3,047 to 3,045 or map position 0.614. Extending counterclockwise from this AUG signal there is only one open reading frame, which can code for a putative t antigen of 100 amino acids in length. If the early mRNA of BKV is spliced, then the regions between nucleotides 3,047 to 2,808 and 2,725 to 884 can code for a T antigen 694 amino acids in length. The sequences of the deduced T antigens in BK virus share 71% amino acid homology with those in simian virus 40, whereas the coding sequences of the two viruses share 70% DNA homology. Comparison of DNA sequences and evaluation of homology measurements between these two viruses are discussed.

Antigens, Neoplasm↗

Skeletal muscle strength during exposure to hypobaric hypoxia.

To assess the effects of acute exposure to hypobaric hypoxia and acute mountain sickness (AMS) on skeletal muscle strength, 10 healthy young men were studied before, during, and after a 48-h sojourn at a simulated altitude of 4,572 m (15,000 feet). Measurements were made of isokinetic (180 degrees, 36 degrees, and 0 degrees/s) knee extensor strength; isometric strength of upper torso, knee, and trunk extensor muscles; and strength endurance of knee extensor and elbow flexor muscles during a bout of repeated isokinetic contractions. There were no significant differences between strength measurements at sea level and after 2 and 24 h of hypoxic exposure. After 48 h of exposure, means of strength measurements were increased relative to sea-level values but the difference was statistically significant in the case of only one test; namely, isometric strength of the upper torso. Strength endurance was unchanged throughout the exposure. Symptoms of AMS were absent after 2 h, most pronounced after 24 h, and although somewhat reduced, still present to a significant extent after 48 h of hypoxia. Thus, despite the occurrence of AMS, muscle strength was unimpaired during acute hypoxic exposure.

Adult↗

Relaxation rate of constituent muscle-fibre types in human quadriceps.

1. Muscle fibres may be subdivided into type I (with slow-twitch contractile properties) and type II (fast-twitch) depending on their myosin adenosine triphosphatase activity. In voluntary isometric contractions type I fibres are utilized at low forces (less than 20% of maximum) whereas type II fibres are recruited in addition at high forces. This physiological recruitment order has enabled us to measure the relaxtion rate of type I and II fibres in vivo in normal human subjects. 2. Relaxation rate was measured in 16 subjects from low (10% of maximum) and maximum isometric quadriceps contractions and the muscle-fibre type composition determined from needle-biopsy specimens in 10 subjects. The relaxation rate of type II fibres was calculated to be twice as fast as that of type I. 3. It was not possible to estimate, from studies in 33 quadriceps muscles (25 normal subjects), the contribution of type II fibres to overall fibre area from the relaxation rate as determined from electrically stimulated isometric contractions.

Adenosine Triphosphatases↗

Muscle relaxation rate, fibre-type composition and energy turnover in hyper- and hypo-thyroid patients.

1. Quadriceps strength, relaxation rate, fibre-type composition and energy-turnover rate during a submaximal contraction have been measured in hypo- and hyper-thyroid patients and compared with findings in normal subjects. 2. Six out of eight hypothyroid patients had normal strength whereas four out of five hyperthyroid patients were weak. 3. Relaxation rate was decreased in all the hypothyroid patients but increased in only three out of five hyperthyroid patients. 4. In hypothyroidism there was a marked reduction in the percentage contributed by type II fibres to muscle cross-section, partly due to type II atrophy but also due to a decrease in the relative frequency of type II fibres. In hyperthyroidism both fibre types tended to atrophy. 5. The rate of ATP turnover during submaximal contraction held to fatigue was reduced in hypothyroidism. This was probably due to decreased ATP utilization rather than an impaired supply of energy-supplying substrates. In hyperthyroidism the rate of ATP turnover was increased. 6. Altered relaxation rate and ATP-turnover rate may be explained on the basis of changes in myosin ATPase activity with thyroid status. Changes in muscle-fibre-type composition, as determined histochemically, could not per se account for the functional abnormalities.

Adenosine Triphosphate↗