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Biomedical subjects

J S Davidson

Publications and source records attributed to J S Davidson.

At least 91 records · Page 5Linked to original sources
PubMed1984

The early diagnosis of acute gall-bladder disease: the accuracy of overnight eight-hour infusion cholangiography.

The reliability of overnight 8-hour infusion cholangiography in confirming the diagnosis of acute cholecystitis or biliary colic was assessed by a prospective study in 100 patients. 55 positive infusion cholangiograms were subsequently confirmed at operation in 45 patients and by cholecystogram in 10 patients who did not have surgical treatment. The absence of false positive examinations is of fundamental importance if early cholecystectomy is to be performed without the risk of an unnecessary laparotomy. Infusion cholangiography proved to be a safe, simple and reliable investigation in the confirmation of acute gall-bladder disease.

Acute Disease↗
PubMed1982

Amniotic fluid acetylcholinesterase electrophoresis in the prenatal diagnosis of neural tube defects.

Amniotic fluid acetylcholinesterase electrophoresis has become available as a test for the prenatal diagnosis of open neural tube defects. The results of acetylcholinesterase electrophoresis on 125 amniotic fluid samples, including 18 from fetuses with open neural tube defects, are presented. These results indicate that this test, in conjunction with alpha-fetoprotein measurement, is of considerable practical value.

Acetylcholinesterase↗
PubMed1982

Sodium-potassium cotransport activity as genetic marker in essential hypertension.

Sodium-potassium cotransport activity is thought to be defective in essential hypertension and could be a useful genetic marker for susceptibility to essential hypertension. In this study cotransport activity in subjects with hypertension was compared with that in normotensive controls. The effects of ethnic differences, environment, and antihypertensive drugs were also studied. Mean cotransport activity was lower in hypertensive subjects than in controls of the same ethnic groups. There was, however, a large overlap between controls and hypertensive subjects. No ethnic or environmental influences were found. The large overlap found suggests that sodium-potassium cotransport activity is not a useful genetic marker in essential hypertension.

Adult↗
PubMed1980

Measurement of total ammonia levels in plasma, whole blood, and cerebrospinal fluid of dogs using an ion-specific electrode.

[NH3] (dissolved NH3 plus NH4+) was measured in cerebrospinal fluid (CSF) and blood of awake and anesthetized dogs using an ion-specific electrode. When oxalate was used as an anticoagulant, plasma [NH3] was increased by 46% in comparison with plasma [NH3] when the anticoagulant was "NH3-free" heparin. As whole blood [NH3] was the same using either anticoagulant, the choice of anticoagulant influenced distribution of NH3 between plasma and red blood cells. In awake animals venous [NH3] was the same as arterial [NH3]; however, following anesthesia plasma [NH3] increased significantly and there was a tendency for venous [NH3] to exceed arterial [NH3]. In some dogs, anesthesia resulted in marked changes in arterial and (or) venous plasma and whole blood [NH3]. Examination of the red blood cell : plasma ratio for [NH3] indicated that ammonia may not be distributed passively between the two compartments. Similarly, calculations of ammonia distribution between CSF and plasma indicated that ammonia is unlikely to be distributed by passive forces between CSF and plasma.

Ammonia↗
PubMed1976

High peptic stricture of the oesophagus.

Fifty-seven patients with high peptic stricture and the lower oesophagus lined by columnar epithelium are considered from the clinical point of view. Information from 115 cases of low stricture is introduced for comparison. The average age of adult patients was 62 years with a sex incidence of 36 females to 21 males. There is little difference between the symptoms of high and low strictures. Radiologically, the majority of high strictures are short and smooth but other types are illustrated. Carcinoma and congenital mid-oesophageal web are considered in the differential diagnosis. There was an associated duodenal ulcer in 10% of cases. In six patients, a high stricture developed soon after an abdominal operation or period of recumbency. Two patients are illustrated showing the process of stricture formation. Four patients are described who had gastric-lined oesophagus but no ulceration of stricture. One patient had a Barrett ulcer in addition to a high stricture. A patient is described in whom the mucosa of the lower oesophagus appeared to be replaced by jejunal mucosa following oesophagojejunostomy. One patient is illustrated in whom a stricture was seen to ascend the oesophagus over a period of six years. Thirty-three patients were treated by dilatation and 24 by operation. Hernial repair is an effective form of treatment. Of 19 patients treated in this way, significant dysphagia persisted in two and slight dysphagia in one. The clinical findings are discussed in relation to the origin of columnar epithelium in the oesophagus.

Adolescent↗
PubMed1968

Hiatal hernia.

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Hernia, Diaphragmatic↗
PubMedDate not supplied

Heterophile antibodies may cause falsely lowered serum cortisol values.

OBJECTIVE: We describe a case where interference by heterophile antibodies in a cortisol immunoassay led to a falsely lowered serum cortisol level. CASE DATA: As part of a diagnostic workup for fatigue, a 42-yr-old woman was found to have a low 9.00 h serum cortisol and an abnormal Synacthen stimulation test consistent with adrenal insufficiency. On insulin hypoglycemia testing, markedly discrepant cortisol levels were obtained from paired samples tested by two different immunoassays. Further tests, including plasma ACTH and overnight metyrapone test, confirmed normal hypothalamic-pituitary-adrenal axis function. Negative interference on the initial immunoassay from a heterophile antibody in the patient's serum was detected, thereby explaining the abnormal results. CONCLUSIONS: This report demonstrates that potentially significant consequences can arise from the failure to consider heterophile antibody interference. Clinicians who interpret test results need to be aware of the potential for interference in immunoassays by heterophile antibodies.

Adrenal Insufficiency↗
PubMedDate not supplied

In vitro elution of gentamicin, amikacin, and ceftiofur from polymethylmethacrylate and hydroxyapatite cement.

OBJECTIVE: To compare the elution characteristics of ceftiofur and liquid and powdered gentamicin and amikacin from polymethylmethacrylate (PMMA) and from hydroxyapatite cement (HAC). METHODS: PMMA and HAC beads in triplicate were impregnated with various amounts and formulations of antibiotics. Beads were immersed in 5 mL of phosphate buffered saline that was replaced at 1, 3, 6, and 12 hours, and 1, 2, 3, 5, 7, 10, 14, 18, 22, 26, and 30 days. The eluent was stored at -70 degrees C until assayed within 2 weeks by microbiological assay (gentamicin and amikacin) or capillary electrophoresis (ceftiofur). RESULTS: Rate of elution for all beads was greatest within the first 24 hours. Cumulative release of total antibiotic dose from beads over 30 days was significantly greater from HAC than PMMA. Antibiotic elution was directly related to the amount of antibiotic incorporated into the cement. Powdered and liquid forms of gentamicin had similar elution rates from PMMA. Elution of amikacin from PMMA beads was greater when the powdered form was used compared with liquid amikacin. Eluent concentrations of ceftiofur were similar to those of the aminoglycosides during the first 3 to 7 days but then decreased precipitously by comparison. CONCLUSIONS: Elution of antibiotics from HAC was greater than from PMMA. Gentamicin- and amikacin-impregnated PMMA and HAC released bactericidal concentrations of antibiotic for at least 30 days. Ceftiofur-impregnated PMMA or HAC is unlikely to provide long-term bactericidal concentrations. CLINICAL RELEVANCE: Gentamicin and amikacin elute effectively from PMMA and HAC.

Amikacin↗
PubMedDate not supplied

Pane in the back.

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Ankle↗