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Biomedical subjects

A J Wilson

Publications and source records attributed to A J Wilson.

At least 145 records · Page 8Linked to original sources
PubMed1992

Some 'antiphospholipid antibodies' bind to beta 2-glycoprotein I in the absence of phospholipid.

Some antiphospholipid antibodies (aPL) only bind to anionic phospholipids in the presence of a serum cofactor, beta 2-glycoprotein I (beta 2GPI). Whether these aPL can bind to beta 2GPI in the absence of phospholipid is controversial. We have purified anticardiolipin antibodies (aCL) from the plasma of four patients and beta 2GPI from normal plasma by solid phase affinity methods. All four aCL bound to cardiolipin and phosphatidylserine in the presence of beta 2GPI but not in its absence. The binding of two of the antibodies to cardiolipin and phosphatidylserine at various concentrations of human beta 2GPI was compared with that obtained using 10% bovine serum. The two antibodies responded differently to increasing beta 2GPI concentrations, and binding to phosphatidylserine was relatively greater than to cardiolipin using human beta 2GPI. All four aCL bound to plastic plates coated with beta 2GPI in the absence of phospholipid, and beta 2GPI in the fluid phase had no effect on binding. Binding to beta 2GPI coated plates was increased equally when bovine serum or bovine albumin were used as the sample diluent in place of gelatine. These findings and those of others have important implications for the design of assays for antiphospholipid antibodies.

Antibodies, Anticardiolipin↗
PubMed1992

Radiographic evaluation of the wrist: what does the hand surgeon want to know?

Congenital, developmental, and acquired wrist deformities predispose patients to characteristic conditions and their associated debilities. The accurate recognition and quantitation of these conditions represent guideposts to treatment and prognosis. The authors present mensuration methods and normal ranges for the important morphologic features of carpal height, ulnar variance, radial inclination, radial length, palmar tilt, and radial shift. These measurements assume importance in the description and quantitation of many conditions. The authors review the radiographic features and diagnosis of dissociated and nondissociated carpal instability, scapholunate advanced collapse, ulnar translocation, ulnocarpal impaction, and ulnoradial impingement.

Female↗
PubMed1992

Gross and microscopic lesions of naturally occurring tuberculosis in a captive herd of wapiti (Cervus elaphus nelsoni) in Colorado.

A Mycobacterium bovis-infected herd of captive wapiti (Cervus elaphus nelsoni) in Colorado was depopulated after lesions of bovine tuberculosis were confirmed in 8 of 10 tuberculin skin test reactors. Of the 43 animals > 1 year of age, 26 had gross lesions suggestive of tuberculosis, 24 had microscopic lesions of tuberculosis, and 23 had acid-fast bacilli associated with the lesions. Lungs and retropharyngeal lymph nodes were the most frequently affected sites. Most lesions grossly and microscopically resembled tuberculosis in cattle; however, some lesions resembled abscesses or ovine caseous lymphadenitis lesions. Special stains and immunohistochemical techniques labeled few to numerous mycobacteria associated with the lesions.

Animals↗
PubMed1992

Dynamic analysis of cardiac R-R intervals in normal infants and in infants who subsequently succumbed to the sudden infant death syndrome.

Infants who subsequently succumb to the sudden infant death syndrome (SIDS) have higher heart rates and reduced heart rate variation compared with other infants. We examined dynamic changes in cardiac interbeat intervals to explore these differences in cardiac control. Recordings of electrocardiographic activity and respiratory movement were acquired from 13 SIDS victims before their deaths. Moment-to-moment changes in R-R intervals during quiet sleep, rapid eye movement sleep, and waking were compared with values of 13 matched control infants. For each sleep-waking state, every R-R interval was plotted against the previous interval (Poincaré plots), and each change in interbeat interval was plotted against the previous change. Dispersion of interbeat intervals at different heart rates was reduced in SIDS victims, resulting in Poincaré plots markedly different from those of controls. The dispersion, sampled at the 10th and 90th percentiles of heart rates, was reduced across all sleep-waking states in SIDS victims. At high heart rates, the difference between groups disappeared after correcting for basal rate; however, the reduced range at low heart rates was independent of basal rate. SIDS victims also showed smaller beat-to-beat changes in heart rate and fewer sustained runs of consistent heart rate changes during waking relative to controls. The differences in cardiac rate dynamics suggest altered autonomic control in infants who succumb to SIDS. We speculate that the autonomic disturbance may lead to cardiac instability or may indicate CNS alterations with the potential to affect other vital functions.

Autonomic Nervous System↗
PubMed1992

Sleep state organization in normal infants and victims of the sudden infant death syndrome.

Infants at increased risk of the sudden infant death syndrome (SIDS) show abnormal patterning of sleep-waking states. It was hypothesized that infants who were to die of SIDS would show abnormalities of sleep state distribution prior to their deaths. Twenty-two 12-hour recordings were obtained from infants who subsequently died of SIDS, and sleep state patterns were compared in these records and 66 records of age-matched control infants. Each 1-minute epoch was classified as quiet sleep, rapid eye movement (REM) sleep, waking, indeterminate state, or artifact-contaminated. Victims of SIDS showed less waking and more sleep than control infants during the early-morning hours. Victims of SIDS younger than 1 month of age showed significantly more epochs classified as REM sleep across the night and significantly fewer epochs contaminated by artifacts relative to control infants. Further analysis indicated that the increased number of REM epochs resulted from fewer artifact-contaminated epochs, suggesting reduced motility during REM sleep in the SIDS victims compared with the control infants. The finding of decreased waking time during the early morning is of particular importance since most SIDS deaths occur during this portion of the day. The findings of altered sleep patterns in SIDS victims suggest that central neural changes are associated with SIDS risk.

Analysis of Variance↗
PubMed1991

CD1a and S100 antigen expression in skin Langerhans cells in patients with breast cancer.

Langerhans cells (LCs) are dendritic, antigen-presenting cells found in the epidermis. This study investigates the effect of early breast cancer on the expression of CD1a and S100 antigens by these cells. LCs were counted and expressed as cells/mm of epithelial basement membrane on biopsies from the skin overlying the tumour and from biopsies distant from the tumour. A control study was performed on normal breast skin, not adjacent to a lesion, from women with benign breast disease. The LC count of 18 patients undergoing biopsy for benign breast disease indicated a mean of 26 cells/mm [95 per cent confidence interval (CI) 23-29] and a S100/CD1a ratio of 70 per cent. In 35 cases of early breast cancer, the CD1a-positive LC count in the epidermis overlying the carcinoma (mean 26/mm; 95 per cent CI 23-29) was similar, but the count made on biopsies distant from the tumour (mean 21/mm; 95 per cent CI 19-23) was significantly smaller. The percentage ratio of S100/CD1a was 71 per cent over the carcinoma and 84 per cent in the distant biopsies. The changes were not associated with the presence of nodal metastases or the oestrogen and progesterone status of the primary tumour. The reduction in LC numbers provides a link between decreased monocyte function and the decreased skin hypersensitivity responses found in patients with breast cancer.

Adult↗
PubMed1991

Trypanosoma evansi infection in cattle, buffaloes and horses in Indonesia.

Cattle, buffaloes and horses in several areas of Indonesia were examined for evidence of infection with Trypanosoma evansi by the microhaematocrit centrifugation technique (MHCT) and an enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to T. evansi. Evidence of infection was found in animals at each sampling site although differences were seen in prevalence rates between sites. Prevalence rates in buffalo were usually higher than in cattle in the same area while in horses they were much lower than in cattle or buffalo. An age-dependent prevalence rate was seen in buffalo and cattle with the highest rates seen in animals older than 2 years. These results concur with the view that T. evansi infection is widespread throughout most of the livestock-producing areas of Indonesia. The apparent lack of any obvious disease owing to T. evansi infection in the sampled animals suggests that a form of stability exists in most endemic areas which serves to ameliorate the effect of T. evansi infection and has an immunological basis linked to the parasite's limited antigenic diversity.

Animals↗
PubMed1991

Effects of nonionic contrast media on the blood-brain barrier. Osmolality versus chemotoxicity.

This study was performed to assess the relative contributions of contrast medium osmolality and chemotoxicity to contrast-induced blood-brain barrier (BBB) damage. Experimental carotid angiography was carried out in rabbits with mannitol at an osmolality of 714 mOsm/kg, with the nonionic, monomeric contrast media iohexol and ioversol at similar osmolalities, and with the nonionic, dimeric contrast media iodixanol and iotrolan at osmolalities less than half that of the mannitol. The amount of damage caused by the procedure was assessed by determining the amount of intracerebral extravasation of intravascularly injected technetium-99m-pertechnetate. Mannitol caused no detectable BBB damage, but all four contrast media caused BBB damage that was significantly more severe than that caused by mannitol. The BBB damage caused by carotid angiography with iohexol, ioversol, iodixanol, and iotrolan was not attributable to their osmolalities, but due to some other physical and/or chemical effects of these media on the BBB.

Animals↗
PubMed1991

Chondromyxoid fibroma: radiographic appearance in 38 cases and in a review of the literature.

Thirty-eight cases of histologically confirmed chondromyxoid fibroma were reviewed and their radiographic features recorded. These findings, coupled with a review of the English-language medical literature, suggest that this rare, benign bone tumor has a characteristic but not specific radiographic appearance and may often mimic more common tumors. Chondromyxoid fibroma may occur anywhere in the skeleton, but almost half of the cases occur around the knee. The possibility of chondromyxoid fibroma should always be considered when a focal bone lesion is evaluated that has geographic bone destruction, a sclerotic rim, lobulated margins, and septation. The diagnosis of chondromyxoid fibroma is most likely when the patient is in the 2nd decade of life.

Adolescent↗
PubMed1991

Unidirectional joint communications in wrist arthrography: an evaluation of 250 cases.

Although arthrographically demonstrable communications between various compartments of the wrist occur in older persons without symptoms, similar communications in younger persons may indicate clinically significant posttraumatic ligament tears and other pathologic processes. However, detection of communications varies depending on the arthrographic technique used. It has been claimed that if triple-compartment arthrography is not used in all patients, clinically significant unidirectional ligament tears may be overlooked. We determined the frequency and distribution of unidirectional intercompartmental communications, using a modification of techniques described in the literature. Separate injections of contrast material were made in sequence into the midcarpal, distal radioulnar, and radiocarpal joints of 250 consecutive patients. We found 38 unidirectional communications (17 lunotriquetral, nine scapholunate, three radial capsular, one ulnar capsular, six combined sites, and two indeterminate sites) between the midcarpal and radiocarpal joints. Nine unidirectional communications between the radiocarpal and distal radioulnar joints were found. Comparison of these results with the frequency and direction of unidirectional communications reported by others suggests that demonstration of communications depends on specific technical factors, such as which joint is injected first, the amount of contrast material used, and the delay between injections. This dependence on technical factors raises questions about the value of routine three-compartment wrist arthrography.

Adult↗
PubMed1991

MR examination of the knee: interpretation with multiscreen digital workstation vs hardcopy format.

A multiscreen imaging workstation was compared with conventional hardcopy format for diagnostic interpretation of MR images of the knee. MR examinations from 30 patients were interpreted by two observers using film displayed both on a standard film panel alternator and an eight-screen digital workstation. Arthroscopic examination of these patients disclosed 30 meniscal tears and five anterior cruciate ligament tears in 28 patients. Two patients had normal arthroscopic examinations. The MR examinations were evaluated with a five-point confidence rating scale. Results were correlated with arthroscopic findings, and receiver-operating-characteristic curves were generated from these data. No significant difference was found between the areas under the receiver-operating-characteristic curves for film and digital display. The time required for image interpretation was greater when using the digital workstation than when using the film by a factor of approximately 2.7. Our data indicate that a multiscreen digital workstation can be used for interpreting MR examinations of the knee without impairment of diagnostic performance, but with increased time required for image interpretation when compared with radiographic film and a film panel alternator.

Adult↗
PubMed1991

Photostimulable phosphor digital radiography of the extremities: diagnostic accuracy compared with conventional radiography.

A direct comparison was made between digital and conventional radiographs to assess the relative accuracy of a photostimulable phosphor digital imaging system in detecting and localizing minor trauma in the extremities. Matched sets of images were obtained on 103 patients who came to the emergency department for radiographs of the hand, wrist, foot, or ankle. One set was obtained with a conventional screen/film system. The other set was obtained with photostimulable phosphor digital cassettes. The two sets of images of each patient were independently interpreted by three radiologists in a blinded fashion. The findings of each of these three readers were compared with the consensus opinion of two different radiologists. Receiver-operating-characteristic (ROC) curves were plotted for each of the three readers, areas under the curves were calculated, and true-positive fractions were determined at false-positive fractions of 0.1. Although no significant differences in the areas under the ROC curves for the two imaging systems were detected, conventional radiography showed a slight advantage. However, when true-positive fractions for fracture detection were compared at false-positive fractions of 0.1 a statistically significant difference was shown, with conventional screen/film radiography being more sensitive. This study raises questions about the use of currently available photostimulable phosphor systems for imaging trauma of the extremities and suggests that those systems should not be used exclusively.

Adult↗
PubMed1991

Sleep apnea in infants who succumb to the sudden infant death syndrome.

Previous studies have shown the frequency of respiratory pauses to be altered in groups of infants at risk for the sudden infant death syndrome (SIDS). In this study, we assess the frequency of apneic pauses during quiet sleep and rapid eye movement sleep in control infants and infants who subsequently died of SIDS. Sleep states were identified in 12-hour physiological recordings of SIDS victims and matched control infants, and the number of respiratory pauses from 4 to 30 seconds in duration was computed for quiet sleep and rapid eye movement sleep. SIDS victims 40 to 65 days of age showed significantly fewer apneic pauses than did age-matched control infants across the two sleep states. Fewer short respiratory pauses accounted for most of the reduction in number of apneic events in the SIDS victims during both sleep states. During the first month of life, SIDS victims did not differ significantly from control neonates on this measure. The finding that this respiratory difference exists during the second month of life, just before the period of maximal risk for SIDS, but not earlier, may have implications for the etiology of SIDS deaths.

Electrocardiography↗