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Biomedical subjects

R S Davidson

Publications and source records attributed to R S Davidson.

At least 19 recordsLinked to original sources
PubMed1992

Sonography of the elbow in infants and children.

High-resolution real-time sonography of the musculoskeletal system of infants and young children is being used with increasing frequency, in part because of the inability of plain film radiography to visualize unossified cartilage. Real-time sonography now plays an important role in the evaluation of infantile hip dysplasia, as well as in the identification and aspiration of joint effusion. The purpose of this essay is to illustrate clinical situations in which sonography of the elbow is helpful.

Cellulitis↗
PubMed1992

Cognitive motivations for drinking among alcoholics: factor structure and correlates.

The aims of this study were to: a) Identify factors reflecting reasons for drinking and expectancies regarding the effects of drinking among inpatient alcoholics; b) Examine the relationship between these cognitive "motivations" for drinking and both patterns of alcohol consumption and various personal and social consequences of consumption. The factors which emerged relate to negative mood reduction, positive mood enhancement, and social functioning. Although the factors identified in this investigation were not associated with quantity of alcohol consumed, small to moderate associations were found between scores on three of four factors and a variety of adverse physical and occupational consequences of alcohol abuse.

Adult↗
PubMed1991

A comparison of continuous and episodic drinkers using the MCMI, MMPI, and ALCEVAL-R.

This study was designed to identify clinically meaningful differences between continuous and episodic drinkers who were entering inpatient treatment (N = 125) on the basis of information from intake administrations of the revised Alcohol Evaluation Instrument, the Million Clinical Multiaxial Inventory, and the Minnesota Multiphasic Personality Inventory. Separate discriminant analyses based upon (a) the MCMI and ALCEVAL-R and (b) MMPI and ALCEVAL-R yielded correct classification rates of 86% and 85%, respectively. Both analyses suggest that continuous drinkers may be characterized by greater confused and disorganized thinking, agitation, and cynicism and distrust in interpersonal relationships than are episodic drinkers. In contrast, episodic drinkers appear to have somewhat more socially conforming attitudes that may inhibit daily social drinking. Despite this, episodic drinking was associated with a higher divorce rate (71% vs. 32%) and less occupational stability.

Alcohol Drinking↗
PubMed1991

Torticollis in children.

Torticollis is a common clinical sign that is found in a variety of disorders. Childhood torticollis differs from the adult form in that congenital types are common and many frequently encountered disorders found in adults are unusual. Pediatric torticollis related to otolaryngologic conditions is reviewed, and three illustrative cases are presented.

Child↗
PubMed1991

Development and evaluation of the revised Alcohol Evaluation Instrument.

This study reports on the development of a revised version of the Alcohol Evaluation Instrument (ALCEVAL-R). Items in the four major areas of the ALCEVAL-R were factor analyzed separately and relationships among factors were examined. Results suggest that the ALCEVAL-R measures clinically meaningful aspects of the alcoholic patient's occupational and social status, and reveals important dimensions of alcohol consumption and of the personal and social consequences of alcohol abuse.

Alcohol Drinking↗
PubMed1991

Osteolysis of the calcaneus in a child with localized scleroderma.

In a young girl with localized scleroderma a circumscribed area of lysis developed in the calcaneus beneath the involved skin and soft tissues of the foot. A biopsy revealed vascular changes characteristic of scleroderma associated with infarction and severe resorption of the bone. A geographic pattern of bone destruction in a child with localized scleroderma has not previously been reported.

Biopsy↗
PubMed1990

Fluorescence quenching; a practical problem in flow cytometry.

Dual fluorescence analysis with a single-laser fluorescence-activated cell sorter is dependent on the use of two fluorochromes with similar excitation wavelengths but different emission wavelengths. The dye pair fluorescein and R-phycoerythrin (RPE) have been widely employed for this purpose and interaction between the two dyes has not been observed. Here evidence is presented to show that at high concentrations RPE can completely quench the fluorescein signal in dual fluorescence analysis of human tonsil lymphocytes labelled with pairs of monoclonal antibodies. Reduction in the fluorescein signal correlated with the intensity of red (RPE) staining. This phenomenon can seriously compromise interpretation of dual immunofluorescence carried out on a single laser instrument and can best be avoided by careful analysis of single colour controls.

Antibodies, Monoclonal↗
PubMed1990

The use of fluorescent probes in immunochemistry.

The limitations and advantages of particular dyes for labelling proteins and other biological materials are discussed. Methods available for conjugating dyes to proteins are outlined. Following a discussion of double labelling methods the use of photoactivatable fluorochromes and time resolved fluorescence methodologies are outlined. The reasons for the photoinstability of some fluorochromes are discussed and methods for overcoming the problem are described.

Antigen-Antibody Complex↗
PubMed1990

Neural injuries associated with supracondylar fractures of the humerus in children.

A retrospective review of displaced extension-type supracondylar fractures of the humerus in 101 children who were seen consecutively revealed eighteen associated neural injuries in thirteen children. Nine of the neural injuries in eight patients spontaneously resolved at a mean of 2.5 months (range, 1.5 to five months) after injury. The remaining nine lesions in five patients were explored at a mean of 7.5 months (range, five to fourteen months) after injury, because clinical and electromyographic studies showed no return of function. Neurolysis was performed on eight of the nerves that were explored (in five patients), and the remaining radial nerve was found to be completely lacerated and needed nerve-grafting. The length of follow-up after neurolysis averaged twenty-five months (range, thirteen to forty-four months). All five patients had functional recovery, as documented by range-of-motion, grip-strength and lateral pinch-strength, and von Frey and two-point-discrimination sensory testing. The patient who had had nerve-grafting never recovered neural function, and tendon transfers were needed. We concluded that observation and supportive therapy is the preferred initial approach for children who have a neural injury associated with a closed, displaced supracondylar fracture of the humerus. However, if there is no clinical or electromyographic evidence of return of neural function at five months after injury, exploration and neurolysis should be performed. If the nerve is in continuity, the prognosis after neurolysis is excellent.

Adolescent↗
PubMed1989

Personality and symptom characteristics of continuous vs. episodic drinkers.

This study was designed to identify clinically meaningful differences between Continuous and Episodic Drinkers who were entering inpatient treatment on the basis of demographic, social functioning, and drinking information, as well as scores based on an intake administration of the Millon Clinical Multiaxial Inventory. A discriminant analysis correctly classified 79% of patients into Continuous and Episodic Drinking groups. Variables that had both interpretable loadings on the discriminant function and scores that were associated positively with membership in the Continuous Drinking group include the Psychotic Thinking, Passive-Aggressive, Avoidant, and Psychotic Depression scales of the MCMI and a questionnaire item, "Drinking helps me to work better." In contrast, scores on the Conforming-Compulsive scale of the MCMI were associated positively with membership in the Episodic Drinking group.

Adult↗
PubMed1989

Orthopaedic complications of Lyme disease in children.

Lyme disease is transmitted by the tick Ixodes dammini ("deer tick") or a related ixodid tick. Early diagnosis of children with Lyme disease is difficult because the bite of the ixodid tick often goes unnoticed. Furthermore, erythema chronicum migrans, the characteristic rash of the disease, occurs in less than 50% of cases. However, an awareness of orthopaedic complications of Lyme disease may facilitate an early diagnosis of this disease. Orthopaedic complications of Lyme disease include those which are oligoarticular in nature. Brief intermittent attacks of swelling and pain in one or more joints--primarily large ones--is the pattern of disease most frequently presented. The knee is the joint most commonly affected. In most cases, pain is not severe enough to debilitate the patient or prevent weight-bearing activity. An elevated sedimentation rate is the only consistently abnormal routine laboratory finding in Lyme disease. The only radiographic abnormalities noted in children are effusion and osteopenia. However, the radiograph of a patient known to have Lyme disease may not show any abnormalities at all. Lyme disease shares symptoms in common with septic arthritis and juvenile rheumatoid arthritis. Whenever a distinction between Lyme arthritis and septic arthritis is difficult to make, treatment should be directed at septic arthritis while serological tests for Lyme disease are pending. The physician should consider Lyme disease to be a possible diagnosis of any patient with arthritis and a history of rash or fever, idiopathic neurological disease, or a cardiac conduction defect--especially if there is a history of possible exposure to the carrier tick.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Nondiaphyseal osteoid osteomas in the pediatric patient.

Nondiaphyseal osteoid osteomas lack the classic roentgenographic appearance of diaphyseal lesions. This may delay diagnosis and treatment. This paper reports on seven children with nondiaphyseal osteoid osteoma seen consecutively. Delay in making the diagnoses, once the children were examined by orthopedic surgeons, averaged six months. Absence of the classic roentgenographic appearance led to the delay in these cases. The difficulty in diagnosing the lesion on routine roentgenograms derives from the specific reaction to the lesion by cancellous bone as compared to cortical bone. Bone scans proved to be sensitive at locating a focal area of intense uptake but lacked the specificity to make the diagnosis. Computed tomography (CT) was quite specific at making the diagnosis and localizing the lesion for biopsy. How to differentiate between osteoid osteoma and osteomyelitis by CT is described. When osteoid osteoma is suspected in nondiaphyseal locations, CT is likely to aid in the diagnosis and localization of the lesion for biopsy.

Adolescent↗
PubMed1988

Fluorescence quenching of fluorescein by R-phycoerythrin. A pitfall in dual fluorescence analysis.

The use of a single laser fluorescence-activated cell sorter (FACS) to analyse cellular subpopulations by immunochemical staining requires an alternative dye to fluorescein with appropriate spectral characteristics. R-phycoerythrin (RPE) is widely employed for this purpose. In this study the ability of RPE to quench the fluorescein emission when both are attached to the same cell has been demonstrated by dual labelling of tonsil lymphocytes with pairs of monoclonal antibodies. Reduction of the fluorescein signal correlated with the amount of RPE attached and the relative intensity of emission from the two fluorochromes. The possible photochemical mechanisms which result in a reduction of the fluorescein signal by RPE are discussed. The inclusion of control tests, in which RPE is omitted, is recommended in order to avoid misinterpretation of the results of subpopulation analysis by single laser FACS - especially when low levels of fluorescein staining are obtained.

Antibodies, Monoclonal↗
PubMed1987

Problems associated with distinguishing between singlet oxygen and electron transfer photooxygenation reactions.

In the introduction a review is given of the various methods available for probing the mechanism of photooxygenation reactions. To illustrate the methodology, some new results on the photooxygenation of alpha-ketocarboxylic acids and esters is given in which it is shown that these compounds sensitise singlet oxygen formation but are relatively unreactive to this oxidising species. Alternative mechanistic schemes are proposed.

Carboxylic Acids↗
PubMed1987

Reliability and factor structure of the Alcohol Evaluation Instrument.

This study reports on the reliability and factor structure of an instrument called the ALCEVAL (Alcohol Evaluation Instrument). Results of this investigation reveal that the VA inpatient alcoholics in this study reported reliably on a variety of items on this structured self-report inventory. A factor analysis of reliable ALCEVAL items reveals that the instrument taps a variety of rather narrow dimensions pertaining to: onset and duration of drinking problems, family history, employment history, marital and family distress, and education and self-control of drinking behavior. Results of this investigation add to the growing body of research suggesting that the self-reports of alcoholics may be considered reliable particularly when obtained under standardized testing conditions.

Adult↗
PubMed1987

Lyme arthritis in children. An orthopaedic perspective.

The cases of forty-three children with clinical and serological evidence of Lyme arthritis that was diagnosed between August 1983 and July 1985 were evaluated. The mean length of follow-up was twenty months, with a range of five to thirty months. All of the children lived in or had visited an area where the disease was known to be endemic. Arthritis was the presenting feature in more than half of the children, and half of the children had initially consulted an orthopaedic surgeon, none of whom made the correct diagnosis. Only twenty patients had a history of erythema chronicum migrans, the characteristic rash that precedes the arthritis, and for only nineteen children was there any recollection of having been bitten by a tick. Three patients had Bell palsy and one had a popliteal cyst in conjunction with the arthritis. All of the patients had oligoarticular involvement. The knee was involved in all but two patients. Recurrent attacks of synovitis were common. Effusion was the only radiographic abnormality that was observed, and it was found in thirty-two patients. The sedimentation rate was elevated in thirty of thirty-six patients. Immunofluorescent serology for Lyme disease, which is sensitive and specific, was uniformly positive. Of thirty-three patients who were treated with oral administration of penicillin or tetracycline alone, thirty-one responded, while two patients who had recurrent attacks of the disease responded to parenteral administration of antibiotics. The remaining ten patients responded to combinations of orally and parenterally administered antibiotics. Longer follow-up is needed to further document the apparently low rate of relapse after antibiotic therapy in this young population.

Adolescent↗
PubMed1986

Concurrent validity of the clinical symptom syndrome scales of the Millon Clinical Multiaxial Inventory.

This study examined relationships between the clinical symptom syndrome scales of the Millon Clinical Multiaxial Inventory (MCMI) and the various clinically meaningful mood or symptom states measured by the six Profile of Mood States (POMS) scales (N = 243). The MCMI symptom scale--POMS symptom/mood scale relationships found in this study were compared with MCMI symptom scale--MMPI and SCL-90 symptom/mood scale relationships reported in the MCMI manual (Millon, 1983). Results of the present investigation, when combined with results of the previous analyses reported in the MCMI manual, reveal a number of consistent associations of moderate strength between MCMI symptom scales and selected mood or symptom scales from the MMPI and Symptom Checklist-90 as well as from the POMS. Although most relationships between the MCMI symptom scales and the symptom/mood scales of the POMS, MMPI and SCL-90 were consistent with expectation, the Anxiety, Dysthymia and Psychotic Depression scales of the MCMI show limited ability to discriminate appropriately between anxiety and depression in several of the concurrent validity analyses considered herein.

Adult↗