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Biomedical subjects

C B Styles

Publications and source records attributed to C B Styles.

11 recordsLinked to original sources
PubMed1998

The effects of carotid endarterectomy on ocular haemodynamics.

PURPOSE: To determine the profile of blood flow velocities and resistive indices in the ocular vessels of patients with atherosclerotic carotid disease and characterise the effect of endarterectomy on these parameters. METHODS: Following a preliminary study on healthy volunteers, ophthalmic colour Doppler ultrasound examinations were performed on 27 male and 11 female patients with carotid disease. These measurements were compared with central retinal artery perfusion pressures and intraoperative internal carotid artery stump pressures. RESULTS: Significant changes were seen on the endarterectomised side. The peak systolic velocity in the ophthalmic artery, and resistive indices in the ophthalmic artery, central retinal artery and nasal posterior ciliary artery, rose from pre-operative values. No correlation between colour Doppler ultrasound measurements and intraoperative internal carotid artery stump pressures was present. When compared with ophthalmodynamometry readings, a relationship was noted with maximum velocities in the central retinal vein. CONCLUSION: Carotid endarterectomy alters the haemodynamics in selected vessels of the ocular circulation as measured by colour Doppler ultrasound, but more work is required to determine the clinical utility of this investigative modality.

Adult↗
PubMed1998

Bone tracer uptake in a ureteric calculus.

Technetium-99m methylene diphosphonate was observed to concentrate in a mildly obstructive left ureteric calculus. The bone scan findings alerted the clinicians to this possibility, which was subsequently confirmed and the patient successfully treated. The stone was heterogeneous in texture and predominantly formed from magnesium ammonium phosphate. At extraction the major fragment contained 0.4% of the injected bone tracer dose and autoradiography demonstrated peripheral tracer distribution within the calculus.

Aged↗
PubMed1992

Identification of the site of severe colon bleeding by technetium-labeled red-cell scan.

In cases of severe colon bleeding, it is more important to know the site than the cause, in case surgery is required. Technetium-labeled red-cell scan (TLRCS) is known to identify the site of bleeding at the rate of 0.1 ml per minute or more. The aim of this retrospective study was to see whether TLRCS was a reliable indicator of the site of severe colon bleeding. A retrospective study was made of patients investigated in this way for acute, severe colon bleeding at St. Vincent's Hospital, Melbourne, from 1984 to 1988 (five years). TLRCS identified the site of bleeding in less than half of the cases but correctly identified the site in all nine patients in whom bleeding was so severe as to require emergency surgery, avoiding total colectomy in eight cases.

Aged↗
PubMed1985

Ultrasound in the diagnosis of jaundice--a review.

A retrospective study of 92 jaundiced patients undergoing ultrasound examination was undertaken to assess the clinical utility of this test. The patients were graded according to the likelihood of biliary obstruction. In those in whom biliary obstruction was proven to be present, the sensitivity of ultrasound to detect the obstruction was 91% and the test specificity was 100%. In patients who had undergone cholecystectomy no increase in the diameter of the common duct was observed. Liver function tests proved to be unreliable in discriminating between extrahepatic obstructive jaundice and other forms of jaundice. Ultrasound scanning is a useful screening test in the diagnosis of the jaundiced patient. However, follow-up is suggested for those with a negative result of this test but in whom biliary obstruction is suspected. An approach to the investigation of the jaundiced patient should include early ultrasound examination in those with possible biliary obstruction.

Adolescent↗
PubMed1985

The detection of abscesses with diffusible tracers.

In six patients with suspected infection, scintigraphy with diffusible tracers outlined the margins and central portion of an abscess. An animal model was developed to study this process quantitatively. Small inflammatory lesions yielding volumes of pus of 0.1-0.2 mL were shown to have increased blood volume of 0.7 +/- 0.5 mL, increased blood flow by a factor of three and increased extracellular fluid volume of 10 +/- 6 mL. This supports the patient data and indicates that the pathophysiologic features characterising the clinical studies are hyperemia and oedema associated with an abscess. The slow, central area of tracer diffusion corresponded to the presence of pus. Scintigraphy with 99mTc-DTPA is a convenient way of detecting suspected inflammatory lesions and localising collections of pus.

Abscess↗
PubMed1985

Omega iodo fatty acid scintigraphy--what are we measuring?

In an open chested dog model utilizing dual isotope techniques (125I heptadecanoic acid and 9, 10 3H palmitic acid), sequential myocardial biopsies were performed to: validate the scintigraphic background subtraction technique for the iodo fatty acid, compare the myocardial activity time course for the fatty acids and by TLC methods determine the chemical form of the myocardial activity and to study the influence of free iodide on the overall time-activity pattern. The findings supported the method of background subtraction and demonstrated a similar activity-time course for the two fatty acids. In spite of this, approximately 30% of the myocardial activity (125I) was in the form of free iodide which suggested that the rate of diffusion of iodide may be an important kinetic element in the system. Some differences in the lipid form of the radioactivity (3H, 125I) were noted.

Animals↗
PubMed1984

Gastroesophageal reflux and transit scintigraphy: a comparison with esophageal biopsy in patients with heartburn.

A method for combining scintigraphic studies of esophageal transit and gastroesophageal (GE) reflux is presented. Thirty-two patients with symptoms of GE reflux were studied. The severity of their symptoms was compared to nuclear medicine studies and esophageal mucosal biopsy. Fifteen healthy volunteers were studied as a control group for scintigraphy. The sensitivity of reflux scintigraphy to detect GE reflux as determined by esophageal histology was 70% and its specificity 87%. No relationship was observed between the magnitude of symptoms and the volume of GE reflux. A higher incidence of esophageal transit abnormalities was observed in those patients with histologic features of GE reflux than in those with normal histology. The combination of esophageal reflux and transit scintigraphy provides a way of studying some of the esophageal motor abnormalities associated with GE reflux. For clinical purposes GE reflux scintigraphy seems unsuitable as a single screening test.

Adolescent↗
PubMed1984

Esophageal transit scintigraphy--a cautionary note.

Esophageal transit scintigraphy and esophageal manometry were compared in forty-two patients with symptoms of esophageal disease. Fifteen healthy volunteers were studied as a control group for the scintigraphic investigation. Agreement between the tests was present in 79% of patients. In all the five patients in whom the esophageal manometry was abnormal and the esophageal transit study was normal, the manometric finding was "giant esophageal contractions." In four of the control group an abnormal transit pattern was observed on one of two esophageal studies. Esophageal transit scintigraphy has some limitations as a screening test for esophageal motor dysfunction.

Adolescent↗
PubMed1983

Effect of doxorubicin on [omega-I-131]heptadecanoic acid myocardial scintigraphy and echocardiography in dogs.

The effects of serial treatment with doxorubicin on dynamic myocardial scintigraphy with [omega-I-131]heptadecanoic acid (I-131 HA), and on global left-ventricular function determined echocardiographically, were studied in a group of nine mongrel dogs. Total extractable myocardial lipid was compared postmortem between a group of control dogs and doxorubicin-treated dogs. A significant and then progressive fall in global LV function was observed at a cumulative doxorubicin dose of 4 mg/kg. A significant increase in the myocardial t1/2 of the I-131 HA was observed only at a higher cumulative dose, 10 mg/kg. No significant alteration in total extractable myocardial lipids was observed between control dogs and those treated with doxorubicin. Our findings suggest that the changes leading to an alteration of myocardial dynamic imaging with I-131 HA are not the initiating factor in doxorubicin cardiotoxicity.

Animals↗