Search PubMed⌕ Search

Biomedical subjects

R J Davidson

Publications and source records attributed to R J Davidson.

216 records · Page 12Linked to original sources
PubMed1970

A survey of infectious mononucleosis in the North-East Regional Hospital Board area of Scotland, 1960-9.

This report, based largely on 1258 laboratory proven cases of infectious mononucleosis (IM) detected in the North-Eastern Regional Board area of Scotland during the years 1960-9 inclusive, describes and discusses some of the epidemiological and diagnostic aspects of the disease.During the period of study, the annual rate of incidence increased fourfold from 11.1 to 44.3 cases per 100,000 population. Evidence is presented to indicate that this does not represent a true increase in prevalence but reflects improvements in disease detection. The annual incidence rates as reported by the C.D.S. for 1967-9 inclusive are regarded as a considerable underestimation of the ;true' incidence of the disease. Over a 3-year period an annual incidence equivalent to 100 per 100,000 population was found in each of two selected group practices. This value was constant and is thought to approximate the ;true' incidence of symptomatic, seropositive IM in the general community.Of the 1258 seropositive cases, 48.7% were males and 51.3% females. The peak age incidence was 15-19 years for both sexes. Twenty-one per cent of the cases were in children under 15 years and only 8.1% in adults older than 25 years. No significant variation was found in the seasonal or urban/rural incidence. Marked differences were found in the leucocyte patterns of seropositive and ;seronegative' cases.

Adolescent↗
PubMed1968

The effect of gamma-irradiation on soluble collagen.

1. A study was made of the effect of gamma-irradiation on the sub-unit composition, as well as the conformational changes taking place in cooled solutions of thermally denatured neutral-salt-soluble and acid-soluble collagen. 2. The increase in negative rotation and viscosity at 15 degrees for irradiated and thermally denatured collagen solutions becomes less as the irradiation dose is increased. 3. The initial effect of gamma-irradiation is the depolymerization of the dimers found in both neutral-salt-soluble and acid-soluble collagen. 4. The principal effect of gamma-irradiation up to 10 Mrads is the fission of peptide bonds, yielding crystalline irradiation-resistant portions of the molecule incapable of associating to the native structure. 5. The effects of gamma-irradiation on both neutral-salt-soluble and acid-soluble collagen are very similar and bear a close resemblance to the effects induced by ultraviolet irradiation.

Acids↗
PubMed1968

Prophylactic folic acid in women with pernicious anaemia pregnant after periods of infertility.

The haematological and obstetric details of five women with Addisonian pernicious anaemia and infertility are described together with those of another patient who developed the anaemia soon after confinement. The implications are discussed, and it is concluded that the prophylactic administration of small doses of folic acid during pregnancy is a safe procedure while the risk of precipitating subacute combined degeneration of the cord in undiagnosed Addisonian pernicious anaemia is hypothetical. Although the mechanism of the infertility in pernicious anaemia remains undefined, several factors which may be of aetiological significance are considered.

Adult↗
PubMed1967

The effect of ultraviolet irradiation on acid-soluble collagen.

1. A study has been made of the effect of ultraviolet irradiation on the conformational changes taking place in cooled solutions of thermally denatured acid-soluble calf-skin collagen. 2. The increase in negative rotation and viscosity at 15 degrees for irradiated and thermally denatured collagen solutions becomes less as the irradiation dose is increased. 3. The principal effect of ultraviolet irradiation is the fission of the primary collagen chains, eventually yielding chain lengths incapable of stabilizing a helical structure. 4. The effects of ultraviolet irradiation on acid-soluble collagen may be closely correlated with similar effects on neutral salt-soluble collagen.

Journal Article↗
PubMed1967

New slide test for infectious mononucleosis.

The rapid and simple slide test for infectious mononucleosis designed by Hoff and Bauer (1965) is designed and compared with a modified sheep-cell slide screening test (Maloney and Malzone, 1949) and the differentenial absorption technique (Davidson, 1937). The claim of Hoff and Bauer that their test is more ;specific' is substantiated. Brief clinical histories illustrate the argument.

Adolescent↗
PubMed1966

The effect of ultraviolet irradiation on collagen-fold formation.

1. A study has been made of the effect of ultraviolet irradiation, in the presence of air and nitrogen, on the conformational changes taking place in cooled solutions of gelatin prepared from thermally denatured neutral-salt-soluble collagen. 2. The increase in negative rotation and viscosity at 15 degrees for irradiated and thermally denatured solutions of collagen becomes less as the irradiation time is increased. 3. The principal effect of ultraviolet irradiation is the fission of the primary collagen peptide chains, eventually yielding chain lengths incapable of stabilizing a helical structure. 4. Irradiation in both air and nitrogen results in a loss of tyrosine, histidine and phenylalanine, with more denaturation occurring in the presence of nitrogen.

Chemical Phenomena↗
PubMed1965

The effect of ultraviolet irradiation on soluble collagen.

1. The effect of ultraviolet irradiation on acid-soluble and neutral-salt-soluble calf-skin collagen was studied by chromatography, gel filtration, amino acid analysis and sedimentation of the sub-units, and the reaction kinetics of degradation were obtained from viscosity and optical rotation measurements. 2. It was demonstrated that, whereas the structure of neutral-salt-soluble calf-skin collagen may be represented by the formula (alpha(1))(2)alpha(2), the acid-soluble extract has the formula alpha(1).(alpha(2))(2). The acid-soluble collagen is also unusual in containing a large amount of a component that could be beta(22). 3. Ultraviolet irradiation causes the progressive degradation of the collagen molecule into smaller molecular fragments that subsequently lose their helical nature. The rate constants show that the denaturation of soluble collagens by ultraviolet irradiation is much slower, under the conditions used, than denaturation by heat or enzymes.

Journal Article↗
PubMedDate not supplied

Effects of personality and semantic content of stimuli on augmenting and reducing in the event-related potential.

Two groups of subjects classified as high vs. low in the need for power (n power) were assessed for augmenting versus reducing in the event-related potential (ERP) elicited by neutral and power-related words. Words at four different intensity levels in each of these two classes were randomly presented and ERPs in response to each word class at each of the four intensity levels were computed from EEG recorded at Fz. The results indicated that the two groups responded differentially to the power-related vs. neutral words. HIgh n power subjects showed reduction in response to both power-related and neutral words while low n power subjects showed augmentation in response to the power-related words.

Adult↗
PubMedDate not supplied

Salivary cortisol as a predictor of socioemotional adjustment during kindergarten: a prospective study.

This study, based on a sample of 172 children, examined the relation between average afternoon salivary cortisol levels measured at home at age 4.5 years and socioemotional adjustment a year and a half later, as reported by mothers, fathers, and teachers. Cortisol levels were hypothesized to be positively associated with withdrawal-type behaviors (e.g., internalizing, social wariness) and inversely related to approach-type behaviors, both negative and positive (e.g., externalizing, school engagement). Higher cortisol levels at age 4.5 predicted more internalizing behavior and social wariness as reported by teachers and mothers, although child gender moderated the relation between cortisol and mother report measures. An inverse relation was found between boys' cortisol levels and father report of externalizing behavior. A marginal inverse relation was found between child cortisol levels and teacher report of school engagement. Behavior assessed concurrently with cortisol collection did not account for the prospective relations observed,suggesting that cortisol adds uniquely to an understanding of behavioral development.

Adaptation, Psychological↗
PubMedDate not supplied

Effect of subinhibitory concentrations of Ciprofloxacin and gentamicin on the adherence of Pseudomonas aeruginosa to Vero cells and voided uroepithelial cells.

The effect of subinhibitory concentrations (1/8 x, 1/16 x, 1/32 x MIC) of ciprofloxacin or gentamicin on the adherence of Pseudomonas aeruginosa to Vero cells and voided uroepithelial cells was studied using two different assay methods. Strains studied included both reference strains and clinical strains, including mucoid and nonmucoid isolates. Sub-MICs of ciprofloxacin decreased adherence to Vero cells and voided uroepithelial cells in 3 of 4 ciprofloxacin-susceptible nonmucoid isolates but not in ciprofloxacin-resistant or mucoid isolates. Sub-MICs of gentamicin significantly reduced adherence in 5 of 7 nonmucoid strains but not in mucoid strains. Gentamicin effect on adherence did not correlate with susceptibility to ciprofloxacin. We conclude that ciprofloxacin susceptibility determines the effect of sub-MICs of ciprofloxacin on P. aeruginosa adherence to Vero cells and voided uroepithelial cells. In addition, both the Vero cell assay and voided uroepithelial cell assay demonstrated similar results.

Animals↗
PubMedDate not supplied

Community care networks: cornerstone of health care reform.

Calls to reform the American health care delivery system include proposals to expand access to insurance and to impose expenditure controls. That approach is flawed and could only lead to an increase in costs. To truly reform the system, the U.S. must fundamentally alter its health care delivery system. One proposal is to create community care networks to coordinate the care of patients. Such a system could operate under a capitated payment system that is publicly accountable.

American Hospital Association↗
PubMedDate not supplied

Antimicrobial treatment options in the management of odontogenic infections.

Most acute orofacial infections are of odontogenic origin. In normal hosts, however, they usually do not occur without some type of predisposing condition. Early recognition and management of acute orofacial infections is critical, because rapid systemic involvement can occur, especially in children. Antimicrobial therapy has an essential role in the management of these infections. If it is initiated before surgery, it can shorten the period of infection and minimize associated risks. The etiology of odontogenic infections is usually attributed to the endogenous flora of the mouth, and not to the introduction of non-resident bacteria. Odontogenic infections are typically polymicrobial; however, anaerobes generally outnumber aerobes by at least four fold. The penicillins have historically been used as the first-line therapy in these cases, but increasing rates of resistance have lowered their usefulness. Bacterial resistance to this class of agents is predominately achieved through the production of beta-lactamases. Clindamycin, because of its broad spectrum of activity and resistance to beta-lactamase degradation, is an attractive first-line therapy in the treatment of odontogenic infections.

Ampicillin↗