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Biomedical subjects

C Davidson

Publications and source records attributed to C Davidson.

At least 37 records · Page 2Linked to original sources
PubMed1990

Serial evaluation of ventricular function after percutaneous aortic balloon valvuloplasty.

To evaluate the serial changes in right and left ventricular performance after percutaneous aortic balloon valvuloplasty, 15 patients, mean age 75 +/- 18 years, and in New York Heart Association (NYHA) class III, were studied with first-pass radionuclide angiocardiography (RNA) immediately before, then 5 minutes, 2 hours, 4 hours, 6 hours, and 3 days after valvuloplasty. No change was observed in heart rate, aortic root systolic pressure, Fick, or RNA cardiac output, amount of aortic insufficiency measured either angiographically or with the regurgitant fraction determination immediately after valvuloplasty. However, significant changes were observed in the peak-to-peak aortic valve gradient (63 to 35 mm Hg; p less than 0.001), mean aortic valve gradient (54 to 33 mm Hg; p less than 0.001), aortic valve area (0.60 to 0.90 cm2; p less than 0.001), and meridional wall stress (79 to 50 10(3) dynes/cm2; p less than 0.01) immediately following valvuloplasty. In addition, left ventricular end-diastolic volume decreased from 186 to 153 ml (p less than 0.001), end-systolic volume decreased from 114 to 86 ml (p less than 0.001), micromanometric left ventricular end-diastolic pressure decreased from 20 to 14 mm Hg (p less than 0.02), and left ventricular ejection fraction increased from 0.39 to 0.45 (p less than 0.001). Peak positive left ventricular dP/dt and end-systolic pressure-volume ratio did not change after valvuloplasty (1700 to 1550 mm Hg/sec, 2.1 to 2.5 mm Hg/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

A semiautomated method for measuring brain infarct volume.

An accurate, reproducible method for determining the infarct volumes of gray matter structures is presented for use with presently available image analysis systems. Areas of stained sections with optical densities above that of a threshold value are automatically recognized and measured. This eliminates the potential error and bias inherent in manually delineating infarcted regions. Moreover, the volume of surviving normal gray matter is determined rather than that of the infarct. This approach minimizes the error that is introduced by edema, which distorts and enlarges the infarcted tissue and surrounding white matter.

Animals↗
PubMed1989

Sexing the human fetus and identification of polyploid nuclei by DNA-DNA in situ hybridisation in interphase nuclei.

Samples of human adult lymphocytes, fetal lymphocytes, amniotic fluid cells, and chorionic villus cells were sexed independently by cytogenetics and DNA-DNA in situ hybridisation to a tritiated Y probe. For the in situ hybridisation analysis, the presence of Y bodies (hybridisation bodies) in 100 interphase nuclei were scored after autoradiography. In all, 82/83 samples were sexed in this way (one technical failure) and 78/82 were sexed by both in situ hybridisation and cytogenetics. There was complete agreement between the two methods. There was a considerable variation (40-100%) in the percentage of interphase nuclei with a hybridisation body among the male samples, but very few nuclei from female samples showed significant hybridisation. In situ hybridisation could be used to sex the conceptus when males but not females are at risk for various X-linked genetic disorders and may also be useful for detecting 45,X/46,XY mosaicism or polyploid/diploid mosaicism. This would be particularly useful for direct preparations of chorionic villus samples, which often prove difficult to analyse cytogenetically but offer the best means of avoiding maternal contamination. Some interphase nuclei had more than one hybridisation body, and this was most commonly found among amniotic fluid cells. Comparison of sizes of nuclei with one or two hybridisation bodies strongly suggested that most of the amniotic fluid cell nuclei with two hybridisation bodies were tetraploid.

Adult↗
PubMed1988

Determination of the molecular size distribution of immunoglobulin G (IgG) in intravenous IgG-albumin formulations by high-performance liquid chromatography.

Recent reports have expressed concern about the safety of intravenous human immunoglobulin G (IgG) preparations. Evidence seems to indicate that aggregates in these formulations are responsible for several adverse reactions in some patients, including anaphylaxis and dyspnea. Therefore, monitoring the molecular size distribution of IgG in these products is essential for ensuring their safety. This paper describes a sensitive and precise two-stage high-performance liquid chromatographic method for determining the molecular size distribution profile of IgG in an intravenous formulation stabilized with albumin. In the first step, all molecular forms of IgG are separated from all molecular forms of albumin by anion-exchange chromatography. In the second stage, a portion of the collected IgG fraction is re-chromatographed by size-exclusion chromatography and separated into its aggregate, dimer, and monomer components. Although some minor losses of aggregate do occur in the procedure, the overall molecular size distribution is not significantly affected. The method described is both time-efficient and accurate, and represents an improvement over existing methods.

Albumins↗
PubMed1988

New child abuse spectrum in an era of increased awareness.

Three hundred eight-two children were evaluated for abuse or neglect during a 30-month period in a pediatric clinic in a county hospital. Fifty-one percent presented for sexual abuse, 34% for physical abuse, and 15% for neglect. Thirteen children were hospitalized. Children examined for sexual abuse had a mean age of 5.8 years and a median age of 5 years; 71% had normal findings on examination, including 48% of those with a history of penetration. Fourteen children were brought for evaluation on the basis of caretakers' misinterpretation, overconcern, or malice. The current spectrum of patients seen for child abuse or neglect reflects increased public and professional awareness of the problem. Earlier recognition of abuse, especially greater readiness to consider sexual abuse, brings younger, less physically injured children to the clinic.

Age Factors↗
PubMed1987

Dietitian-patient communication: a critical appraisal and approach to training.

This paper argues that dietetic interviews are strongly influenced by the traditional model of the medical consultation. Evidence concerning the limitations of this model, in terms of patient satisfaction and compliance, for both doctor-patient and dietitian-patient communication, is reviewed. The interpretation of this evidence suggests that dissatisfaction and non-compliance are related to two sets of variables: cognitive and socio-emotional. A programme of training on communication and counselling skills for dietetic students, which aims to enable students to address these problems, is described and a short-term evaluation by the students of this programme is reported. The paper concludes with an evaluation of the course by staff members and some comments as to possible future trends in dietetic education.

Communication↗
PubMed1986

General medicine in the 'eighties.

The general physician with or without an interest is directly responsible for the initial and continuing care in most acute medicine. Specialty interests cover the whole range of medicine but in most instances are subordinate to the claims of general medicine. Consultants in district general hospitals carry a bigger caseload in acute medicine than their colleagues in teaching hospitals, and this has implications for undergraduate and postgraduate training. The management of patients in intensive care units remains very much the task of the general physician. The general physician will continue to be an essential member of the hospital service in the foreseeable future.

Emergencies↗
PubMed1986

Relations between erythrocyte lithium efflux, blood pressure and family histories of hypertension and cardiovascular disease: studies in a factory workforce and hypertension clinic.

Sodium-dependent lithium efflux was measured in erythrocytes from 399 factory workers and 125 patients attending a hypertension clinic. Thirty-two factory workers had unsuspected essential hypertension (diastolic blood pressure phase V greater than 90 mmHg). These subjects had the same average erythrocyte lithium efflux as those with normal blood pressure, whereas lithium efflux was increased on average in the clinic hypertensives. Lithium efflux was greater in those subjects from both groups who had a family history of high blood pressure. Our clinic hypertensives did not have raised lithium efflux when they were matched for family history; the increased lithium efflux in the group as a whole (and in analysis of published reports) was explained by an excess of subjects with a family history of hypertension. Furthermore, when a family history of hypertension was present, lithium efflux was increased on average only in those whose relatives also had a cardiovascular event associated with their high blood pressure. These results, in conjunction with detailed analysis of the distributions of lithium efflux within the groups, suggest that, though not linked to blood pressure itself, an increase in lithium efflux is an inherited marker for those at risk from the cardiovascular complications associated with high blood pressure.

Adolescent↗
PubMed1986

Enalapril in moderate to severe hypertension: a comparison with atenolol.

Patients with moderate to severe essential hypertension (mean untreated supine blood pressure 190/112 mm Hg) received once daily enalapril 20-40 mg or atenolol 50-100 mg, supplemented if required by hydrochlorothiazide 25-100 mg, in a randomized observer-blind trial. Both regimens produced a highly significant reduction in supine and standing blood pressure. There was no significant difference in the antihypertensive effects of enalapril and atenolol when they were used as monotherapy. After hydrochlorothiazide was added to patients not achieving 'target' blood pressure, the fall in systolic pressure was significantly greater in the enalapril group than in the atenolol group, despite similar dosage of hydrochlorothiazide in the two groups. At the end of 6 months' treatment, a supine diastolic blood pressure of 90 mm Hg or below was achieved in 74% of patients on enalapril plus hydrochlorothiazide and 56% of patients on atenolol plus hydrochlorothiazide. This difference was not statistically significant. A small rise in plasma urea and creatinine was observed in the enalapril group and a small rise of urea only in the atenolol group. These changes were statistically significant but of uncertain clinical importance. This study confirms that once daily enalapril and atenolol, both alone and in combination with hydrochlorothiazide, are effective drugs in the management of moderate to severe hypertension.

Adolescent↗
PubMed1985

Bruising: a useful physical sign in ruptured knee joint.

The clinical distinction of a ruptured knee joint or popliteal cyst from a deep venous thrombosis is important in the planning of treatment, particularly to avoid anticoagulant therapy. Bruising, which may be severe, may occur when inappropriate anticoagulants are administered. It is less well recognised that spontaneous bruising may occur with a ruptured knee joint even when anticoagulant therapy has not been given. A case is presented which demonstrates this useful physical sign and shows also the value of the patient's history in eliciting the diagnosis. The bruising extended to the foot, its gravitational and propulsive advance being halted by the pressure of footwear. This appearance has not been emphasised in the rheumatology literature.

Aged↗
PubMed1985

A study of two diuretic/potassium combinations in heart failure.

The effect of potassium supplements was studied in 28 patients taking long term frusemide (40-80 mg daily). Plasma potassium fell when supplements were stopped, and rose towards prior values on the potassium/frusemide combination, Diumide K. In a crossover study in 14 of these patients comparing equivalent doses of frusemide, Diumide K (frusemide 40 mg, potassium 8 mmol), bumetanide, and Burinex K (bumetanide 0.5 mg, potassium 7.7 mmol) plasma potassium was lower on frusemide than on bumetanide. On Diumide K and Burinex K plasma potassium rose significantly but did not reach the levels on prior therapy. Small doses of potassium in combined formulations seem to be effective in countering the mild hypokalaemia caused by loop diuretics.

Adult↗
PubMed1984

[Influence of the educational course on the future of young persons thought to be mentally deficient].

A survey of mental deficiency among children was carried out in 1967 in the department of Haute-Vienne by the Centre International de l'Enfance and the Institut National de la Santé et de la Recherche Médicale. A representative sample of the children was examined, with data recorded under paediatric, social, and psychological (including an intelligence quotient test, the "WISC") criteria. This study was resumed in 1974 and 1978 in order to determine how the children--by then, between 20 and 26 years of age--had fared. Among the 325 studied, it appears that those educated in specialized facilities succeeded less well than those who followed a normal curriculum. Only 39% of the former vs 58% of the latter won a diploma; 27% vs 17% were fired from jobs; 23% vs 9% experienced adaptation difficulties at work. Even when the IQs and the socioprofessional category of the parents are the same, the differences concerning diplomas (particularly in general, as opposed to professional, education) persist, as do problems in the workplace.

Adult↗