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Biomedical subjects

G J Hunter

Publications and source records attributed to G J Hunter.

49 records · Page 3Linked to original sources

Cholecystokinin cholecystography: a three year prospective trial.

A prospective study was undertaken to assess whether or not cholecystokinin cholecystography was able to predict the long-term results of cholecystectomy. The patients studied were all suffering from abdominal pain which was thought to be biliary in nature but in whom standard oral cholecystography did not reveal gall-bladder disease. There were 48 patients, mostly female, who were followed for 3 or more years after investigation and treatment. Half of the patients underwent cholecystectomy. There was no difference in outcome between those patients treated conservatively and those who underwent cholecystectomy. Cholecystokinin cholecystography was unable to predict the response of the patient to surgery in respect of relief of pain. It is concluded that cholecystokinin cholecystography is not a useful investigation when considering whether or not cholecystectomy would benefit the patient and afford lasting relief from pain.

Adult↗

Digital subtraction angiography in coronary artery bypass graft assessment: clinical applicability.

Application of electrocardiogram gated digital subtraction angiography to the assessment of coronary artery bypass graft function was studied one week to eight years after bypass operation in ten unselected patients with recurrent chest pain. For the digital method, contrast was injected into the ascending aorta via a 4 or 5 French gauge catheter. The results of this technique were compared with those of selective graft and coronary angiography in the same patients by two independent observers. Of twenty six grafts in the series, patency was confirmed in twenty one by both selective and digital angiography. The quality of graft run off, graded by each observer using a simple scoring system, demonstrated six points of inter observer disagreement when standard cineangiograms were used, compared with nine points of disagreement when digital images were used. Digital subtraction angiography provided useful graft visualisation, but was less good than conventional angiography at defining the native coronary circulation. The role of this promising new technique has yet to be established.

Aged↗

In vivo transcription of ribosomal RNA in relation to the mitotic cycle in Physarum polycephalum.

We have investigated the transcription of ribosomal RNA in plasmodia of Physarum polycephalum by a combination of pulse-labelling with [3H]uridine and RNA:DNA hybridization. The DNA used for the hybridization was a HindIII restriction fragment (cloned in bacteriophage lambda) of Physarum ribosomal DNA that carries a substantial fraction of the rRNA genes, enabling the ribosomal transcripts in the newly synthesized RNA to be measured. We found that ribosomal RNA constituted about 40% of the pulse-labelled RNA at all times during the synchronous mitotic cycle.

DNA↗

Rickets in adolescence.

The radiological diagnosis of rickets is mainly based on the widened appearance of actively developing epiphyseal growth plates. In the adolescent with rickets the secondary iliac and ischial ossification centres may be abnormally wide when most other epiphyses have fused. The appearance of the iliac crest is of use both in helping to make the diagnosis and in monitoring the results of treatment.

Adolescent↗

Necrotic carcinoma of the colon.

The radiological appearances of necrotic colonic neoplasms have been described previously and their bad prognosis has been stressed. Four cases of carcinoma of the colon which exhibited characteristic radiological features are described. Survival following surgery in these cases was extremely variable.

Adenocarcinoma↗

Tobramycin in external eye disease: a double-masked study vs. gentamicin.

A double-masked randomized study was conducted at four centers to compare the efficacy and safety of tobramycin and gentamicin ophthalmic ointment in the treatment of superficial external eye disease. Seventy-seven patients with blepharitis and/or conjunctivitis were evaluated for safety, and 56 of the 77 individuals also qualified for evaluation of drug efficacy. After a 10 day treatment regimen, 97% of the tobramycin treated patients and 91.3% of the gentamicin treated patients were clinically cured or improved. Antibacterial effectiveness studies in the conjunctiva showed that tobramycin eradicated or controlled 87.8% of the bacterial infections vs. 77.4% for gentamicin. There was also a 9.3% adverse reaction rate with tobramycin vs. 17.6% with gentamicin. Primary symptoms consisted of erythema, injection, discomfort and itching. All adverse reactions were mild and cleared upon discontinuation of the study drug. While the trends seem to favor tobramycin, no difference was statistically significant at the p less than or equal to 0.05 level. These results indicate that tobramycin is a clinically effective and safe topical antibiotic and that it is comparable to gentamicin for topical treatment of bacterial external eye infections. It also may be better tolerated than gentamicin.

Anti-Bacterial Agents↗

Measurement of stroke volume and cardiac output within a single breath hold with echo-planar MR imaging.

The measurement of cardiac output and ejection fraction is useful in the treatment of diverse cardiac and cardiopulmonary disease states. Although several techniques are available for accurate measurement of left ventricular parameters, assessment of the right ventricle is less well represented. No single method is overwhelmingly superior, each having different strengths and weaknesses. In the present study, the applicability of an echo-planar magnetic resonance (MR) imaging method in which a complete volumetric measurement of the right and left ventricles may be obtained during 12 heart-beats is demonstrated. This rapidity permits imaging during a 15-second breath hold. The authors show in 12 volunteers that breath-hold echo-planar volume measurements of both ventricles were consistent with results obtained with conventional MR imaging methods.

Adult↗

Interactions between DNA and coat protein in the structure and assembly of filamentous bacteriophage fd.

Bacteriophage fd is a class I filamentous virus (others are M13 and f1) that comprises a circular, single-stranded DNA molecule enclosed in a cylindrical protein sheath to form a flexible particle approximately 890 nm long and 7 nm in diameter. The viral DNA contains 6,408 nucleotides incorporating 10 genes, and the protein sheath is composed of about 2,700 major coat protein subunits in a shingled helical array, the symmetry of which is defined by a fivefold rotational axis combined with a twofold screw axis of pitch 3.2 nm. The DNA extends throughout the length of the particle but is not base-paired and has a symmetry different from that of the protein helix. How the DNA is packed remains unclear but the number (2.4) of nucleotides packaged per major coat protein subunit is certainly not integral, in contrast with, say, the packaging of RNA in tobacco mosaic virus. The coat protein subunit is 50 amino-acid residues in length and, in the virus particle, adopts a largely alpha-helical conformation, with the long axis of the helix aligned close to the long axis of the filament. This protein is arranged with its negatively charged N-terminal region on the outside of the filament and its positively charged C-terminal region on the inside abutting the DNA. We report here that positive charge on one of the four lysine side chains in the latter region has a direct effect on DNA packaging, because when this charge is absent, elongated particles are produced with lengths that can be correlated with the residual positive charge in the C-terminal region of the coat protein subunit.

Amino Acid Sequence↗

CT angiography in the rapid triage of patients with hyperacute stroke to intraarterial thrombolysis: accuracy in the detection of large vessel thrombus.

PURPOSE: The purpose of this work was to evaluate the accuracy of CT angiography (CTA) for the detection of large vessel intracranial thrombus in clinically suspected hyperacute (<6 h) stroke patients. METHOD: Forty-four consecutive intraarterial thrombolysis candidates underwent noncontrast CT followed immediately by CTA. Axial source and two-dimensional collapsed maximum intensity projection reformatted CTA images were rated for the presence or absence of large vessel occlusion. Five hundred seventy-two circle-of-Willis vessels were reviewed; arteriographic correlation was available for 224 of these. RESULTS: Sensitivity and specificity for the detection of large vessel occlusion were 98.4 and 98.1%; accuracy, calculated using receiver operating characteristic analysis, was 99%. Mean time for acquisition, reconstruction, and analysis of CTA images was approximately 15 min. CONCLUSION: CTA is highly accurate for the detection and exclusion of large vessel intracranial occlusion and may therefore be valuable in the rapid triage of hyperacute stroke patients to intraarterial thrombolytic treatment.

Adult↗

Measurement of cerebral blood volume with subtraction three-dimensional functional CT.

PURPOSE: To implement a three-dimensional subtraction functional CT technique to permit rapid quantitative mapping of regional cerebral blood volume (CBV). METHODS: The 3-D functional CT technique was implemented in a rabbit model using normal and ischemic animals. Two spiral data acquisitions were performed, one before and one during biphasic administration of contrast material. CBV maps were then produced on a voxel-by-voxel basis through the whole brain. RESULTS: The average normal CBV was 3.3 +/- 0.4 mL/100 g (n = 7), and the regional values were 4.5 +/- 0.6 mL/100 g for cortical gray matter, 2.5 +/- 0.6 mL/100 g for white matter, and 3.7 +/- 0.4 mL/100 g for the basal ganglia. The CBVs in ischemic regions were 1.5 +/- 0.4 mL/100 g, 0.7 +/- 0.7 mL/100 g, and 1.8 +/- 0.9 mL/100 g, respectively. CONCLUSION: Subtraction 3-D functional CT is a fast, potentially cost-effective method with which to assess whole-brain CBV. Because the data collected in 3-D functional CT imaging also can be used to produce large-vessel angiograms, its use in a clinical setting can provide a multiparametric study of cerebrovascular abnormalities that encompasses both large and small vessel circulations for patients being examined for stroke.

Animals↗