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Biomedical subjects

G Hamilton

Publications and source records attributed to G Hamilton.

At least 289 records · Page 16Linked to original sources
PubMed1981

Portal vein prostacyclin activity in experimental portal hypertension in rats.

1. Portal hypertension was produced experimentally in rats by partial ligation of the portal vein. 2. One week later portal veins of these animals were shown to release significantly greater amounts of prostacyclin than control animals. 3. It is postulated that if this response occurs in man, local vasodilatation and inhibition of platelet aggregation may be exacerbatory factors in the severity of haemorrhage from oesophageal varices that complicate portal hypertension.

Animals↗
PubMed1981

Clinical trials for communication aids? A study provoked by the clinical trials of SPLINK.

It is evident that evaluation of communication aids in a functional situation is a necessary part of their development, because of various psychological, social and practical factors related to their acceptability. This is indicated by many unexpected findings in the trial results of one such aid "SPLINK", presented here. This was a multicentre trial with 127 subjects aged between 7 - 82, all of whom had such severe communication problems that spontaneous conversation was limited. The results show that a substantial number of these speech handicapped would benefit from using this aid in various ways and that in some cases it can greatly improve their quality of life. The importance of selection of the aid for the patient and the necessity of expertise on part of the therapist is highlighted by the fact that 80% of users in a previous single centre trial benefitted as compared with 54% in this trial. There are strong indications that attitudes of speech therapists to communication aids range from strongly positive to totally negative; it is vital that they should at least be open-minded as their approach is crucial to outcome.

Adult↗
PubMed1981

"Abnormal" responses of ejection fraction to exercise, in healthy subjects, caused by region-of-interest selection.

We performed serial exercise equilibrium radionuclide angiography in eight normal subjects with each subject executing three tests: control, after nitroglycerin, and after propranolol. The left-ventricular ejection fraction (EF) was calculated by two methods: (a) fixed region-of-interest (FROI) using a single end-diastolic ROI, and (b) variable region-of-interest (VROI) where an end-diastolic and end-systolic region of interest were used. Abnormal maximal EF responses occurred in five of eight subjects during control using FROI but in zero of eight employing VROI (p < 0.05). After nitroglycerin, three of eight subjects had abnormal responses by FROI, but zero of eight were abnormal by VROI (p < 0.05). After propranolol, blunted EF responses occurred in three of seven by both methods. Falsely abnormal EF responses to execrise RNA may occur due to the method of region-of-interest selection in normal subjects with normal or high ejection fractions.

Adult↗
PubMed1980

Eyelid tumors anmd renal transplantation.

The high incidence of malignant neoplasms in renal transplant recipients and other immunosuppressed patients is well recognized. A large proportion of these neoplasms are skin cancers. The frequent occurrence of other ocular complications, such as cataract, elevated intraocular pressure, hypertensive retinopathy, cytomegalovirus retinitis, and herpetic keratitis in patients after kidney transplant, has also been described. This report presents the clinical and histopathologic features of eyelid involvement by keratoacanthoma and squamous cell carcinoma in two patients after renal transplantation and alerts ophthalmologists to the potential for this association.

Adolescent↗
PubMed1980

Epidurography using metrizamide an out-patient examination.

An improved technique of epidurography using metrizamide is described. Fifty patients were examined in order to establish whether the technique can be satisfactorily performed as an outpatient procedure and whether it is as useful as radiculography. The findings indicate that metrizamide epidurography is a safe examination, providing at least as much information as radiculography. Our patients tolerated the examination well, avoiding the after effects associated with intradural techniques, and were able to leave hospital a few hours later. No untoward sequelae occurred.

Ambulatory Care↗
PubMed1979

Jogger's heat stroke.

Two patients developed heat stroke following jogging. Transient disturbance of cerebral function was the most dramatic clinical feature. Although haemorrhagic complications were not seen, marked changes in the haemostatic system occurred with both thrombocytopenia and a reduction of clotting factors synthesised by the liver. No evidence of disseminated intravascular coagulation was found. Heat stroke must now be added to the list of jogging hazards.

Adult↗
PubMed1979

Hypothermia.

Explore the source record for details and available documents.

Humans↗
PubMed1978

The crystal sheaths from bivalve hinge ligaments.

The aragonite crystals in the molluscan bivalve hinge ligament are surrounded by an organic sheath which is distinct from the remainder of the ligament matrix. Methods have been developed to isolate these sheathed crystals from the ligaments of Spisula solidissima and Mercenaria mercenaria employing a papain digestion of the matrix protein. The sheathed crystals from Spisula have a CaCO3/protein ratio of 11.1 and those from Mercenaria a ratio of 29.6. The sheathed crystals and the empty crystal sheaths have been examined by electron microscopy for structural integrity. The sheath proteins exhibit much smaller proportions of the amino acids glycine and methionine than the hinge ligaments. These are characteristic amino acids of high concentrations in the hinge ligaments of both species. The concentrations of acidic and basic amino acids are increased about two fold in the sheaths over those of the ligaments. Otherwise there is little similarity in the amino acid composition of the sheaths in the two species. However, SDS electrophoresis shows the sheaths of both to contain a major protein component with a molecular weight of about 25,000. The sheath protein from the Mercenaria ligament contains about 5% carbohydrate and that of Spisula sheaths less than 1% carbohydrate.

Amino Acids↗
PubMed1978

Axial volvulus of Meckel's diverticulum.

Two cases of axial volvulus of a Meckel's diverticulum associated with a diverticular band are described. In both cases, the pre-operative diagnosis was of acute appendicitis. The importance of further exploration if the appendix is insufficiently inflamed to acount for the symptoms and signs is emphasized.

Acute Disease↗
PubMed1977

Postprostatectomy urinary infection: cystourethrographic study.

Postoperative cystourethrography can be valuable in the diagnosis and management of urinary tract infection and other postprostatectomy complications. The authors have studied 50 patients and recommend voiding cystourethrography prior to endoscopic assessment of bladder outlet resistance. In addition, urinary infection may complicate a clear-cut obstructive lesion and present as a mixture of irritative and obstructive symptoms. The correlation between symptoms and the obstructive lesion is only 40 per cent. There is obviously a need for a more objective evaluation by means of cystourethrography.

Aged↗
PubMed1976

Inhibition of feline collateral vessel development following experimental thrombolic occlusion.

We compared development of feline hindlimb collateral circulation after acute occlusion of the terminal aorta by ligation, thrombus formation, and formation of a "closed" aortic loop containing thromboplastin. Collateral circulation development was assessed by aortograms, scintillation scans, neurological signs following occlusion, measurement of hindlimb muscle blood flow, and forelimb and hindlimb temperature. In cats in which aortic occlusion was the result of ligation or thromboplastin in the aortic loop, paralysis was not evident. Aortograms and scintillation scans indicated hindlimb blood flow. Both muscle temperature and blood flow data indicated that the return of blood flow was rapid. The 5th lumbar artery appears to be the origin of the collateral vessels. The mid-zone component is a dorsal and ventral vertebral route and an epaxial muscle route. The reentry components are the 6th or 7th lumbar arteries. The collateral vessels arise from preexisting collateral vessels. Of those cats in which aortic occlusion was the result of a thrombus, all exhibited paralysis. Aortograms, scintillation scans, muscle temperature, and hindlimb blood flow data indicated reduced hindlimb blood flow. The results suggest that the thrombus has an inhibitory effect on the development of collateral circulation.

Acute Disease↗
PubMed1971

Unilateral decrease in renal vascularity on the "excretory" urogram.

Unilateral decrease in renal vascularity is demonstrated by a new technique for studying the renal vascular parenchyma on the "excretory" urogram.Renal vascularity, decreased on the side of acute ureteral obstruction, returns to normal with the relief of the obstruction.The use of the vascular nephrogram as a screening test for renovascular hypertension is illustrated and discussed.

Humans↗
PubMedDate not supplied

The relationship between prostacyclin activity and pressure in the portal vein.

The effect of portal hypertension (induced by partial ligation) on the ability of the portal vein wall to produce prostacyclin (PGI2) was studied in rats over a period of 6 weeks. PGI2-like activity measured by bioassay was shown to be significantly increased in portal vein segments during established hypertension when compared to control groups. As a collateral circulation developed with consequent fall in portal venous pressure, PGI2-like activity decreased. A positive correlation between PGI2-like activity and portal pressure has been demonstrated. Parallel measurements of this activity by bioassay and radioimmunoassay to 6-keto-prostaglandin-F1 alpha showed a positive correlation (r = 0.88) and suggested that PGI2 is the inhibitory prostaglandin involved. The possible significance of these observations in relation to the hemorrhagic manifestations associated with portal hypertension in man is discussed.

Animals↗