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Biomedical subjects

R Frater

Publications and source records attributed to R Frater.

At least 19 recordsLinked to original sources
PubMed2001

Value of quantitative analysis of mitral regurgitation jet eccentricity by color flow Doppler for identification of flail leaflet.

Early surgical intervention improves the outcome of patients with mitral regurgitation (MR) secondary to flail leaflet. Current criteria for the diagnosis of flail leaflet require a detailed definition of mitral valve anatomy, which is often challenging by transthoracic echocardiography (TTE) and, occasionally, even by transesophageal echocardiography (TEE). We studied 57 patients (mean age 63 +/- 15 years) with anatomically confirmed flail mitral leaflet and a control group of 57 patients (mean age 68 +/-14 years) with at least moderate MR but no flail leaflet. In patients with flail mitral leaflet, the mean angle formed by the axis of the MR jet and the plane of the mitral annulus was 33 +/- 11 degrees and 29 +/- 16 degrees when measured with TTE and TEE, respectively. In controls the mean angle was 66 +/- 16 degrees and 66 +/- 17 degrees by TTE and TEE, respectively (p <0.0001). Based on receiver- operating characteristic analysis, the optimal cutoff jet angle value for diagnosing flail mitral leaflet was 45 degrees with TTE (sensitivity 88%, specificity 88%), and 47 degrees by TEE (sensitivity 88%, specificity 88%). MR jet angles < or =45 degrees were also correctly identified by visual assessment of TTE images in >90% of cases, with good interobserver agreement (k = 0.76). Thus, quantitative analysis of MR jet eccentricity by color flow Doppler is highly sensitive and specific for diagnosing flail mitral leaflet.

Aged↗
PubMed1991

Surgical correction of posttraumatic VSD via the right atrium.

We report the cases of four patients seen with ventricular septal defects (VSDs) resulting from penetrating chest trauma; initial surgical management was via left thoracotomy and comprised relief of tamponade and suture of the surface cardiac wound. A VSD was suspected in all four patients postoperatively on the basis of a holosystolic murmur as confirmed with two-dimensional echo and angiography. Elective surgical repair was undertaken on cardiopulmonary bypass with bicaval cannulation and cardioplegic arrest. The interventricular septum was approached through the right atrium (no attempt was made to free the anterior surface of the right ventricle from adhesions). Three defects were closed directly and one was closed with a pericardial patch. The surgical correction of posttraumatic VSD from a penetrating injury can be safely and effectively achieved via a right atrial approach.

Echocardiography↗
PubMed1988

Double-blind comparison of the efficacy and safety of single doses of meptazinol as a suppository and morphine by i.m. injection.

The analgesic efficacy of a 150-mg meptazinol suppository was compared with that of morphine 10 mg i.m. in the treatment of moderate postoperative pain. Two groups of 15 female patients took part in a 4-h, randomized double-blind, double-dummy study on the first day after elective abdominal hysterectomy. Meptazinol did not provide satisfactory analgesia in five patients (P less than 0.05). A decrease in mean pain scores (linear analogue scale and verbal rating scale) was seen after the administration of meptazinol, but this was not as great as that produced by morphine i.m., nor was it as long in duration. Significant changes in arterial pressure, heart rate and ventilatory rates were not seen in association with the administration of meptazinol, but were observed after the administration of morphine.

Administration, Rectal↗
PubMed1985

A comparison of flow gradients across disposable arterial perfusion cannulas.

Five-hundred members of The Society of Thoracic Surgeons were canvassed to discover which cannulas are currently used for open-heart surgical procedures in adults; 120 surgeons responded. The mean arterial line pressure produced by 29 disposable arterial perfusion cannulas (size range, 16F to 30F) at flow rates of 1 to 5 liters per minute was compared. A roller pump with perfusion tubing 95 mm (0.75 inch) in diameter was used with water as the test solution. Line pressures in these cannulas ranged from 22.4 +/- 2.30 (standard deviation) to 271.0 +/- 6.60 mm Hg at 5 L/min. Four 24F cannulas had gradients of less than 55 mm Hg at a flow rate of 5 L/min, and 6 cannulas--4 of which were 22F and 2, 24F--had gradients higher than 150 mm Hg at 5 L/min. A number of cannulas kinked easily, and these showed marked increases in line pressure. The following results were obtained from this study: (1) a wide range of line pressures was observed in disposable arterial perfusion cannulas currently in clinical use; (2) some cannulas currently used for cardiopulmonary bypass in adults generated excessive line pressure; and (3) both material and design affect function, with some designs being safer than others. Cardiac surgeons should base the choice of an arterial perfusion cannula on the best performance and safest design available to avoid cannula-related problems at operation.

Aorta↗
PubMed1985

A removable polar embedding medium for light microscopy.

A new plastic embedding medium for light microscopy is described. The monomer mixture consists of equal proportions by volume of acrylonitrile, dimethyl acrylamide and methyl methacrylate, and may be polymerized by exposure to ultraviolet light in the presence of benzoin methyl ether as catalyst. Dithiothreitol may also be added to the monomer mix to limit the degree of polymerization. The resulting polymer is soluble in dimethyl formamide.

Acrylonitrile↗
PubMed1983

Inhibition of growth of hair follicles by a lectin-like substance from rat skin.

A small molecular weight (5 000-10 000) substance has been isolated from rat skin by affinity chromatography on a column of acid-hydrolysed Sepharose. The substance agglutinates rabbit red blood cells, inhibits DNA synthesis in rat hair follicles, and causes the appearance of autophagic vacuoles in the epithelial cells of the lower follicle bulb.

Animals↗
PubMed1981

Production of glycosaminoglycans by rat hair follicle cells in vitro.

Cultures of cells from rat dermal tissue, containing a large proportion of cells from the hair follicles, were found to produce glycosaminoglycans. The glycans were associated with the cell aggregates which typically form the such cultures, and also appeared to be present in material which was released from the cells. Examination of the glycosaminoglycan species present in the cultures showed the presence of hyaluronic acid, dermatan sulfate, chondroitin-4-sulfate, heparin and heparan sulfate-C, the first two compounds being secreted into the culture medium. The patterns of synthesis and sulfation of glycosaminoglycans were found to change with continued time in culture.

Animals↗
PubMed1980

The effect of rat serum on the morphology of rat hair follicles in tissue culture.

Rat hair follicles obtained from the skin of 12-day-old animals were cultured in the presence of 20% fetal calf serum and compared with those cultured in the presence of 20% rat serum obtained from animals aged 12-14, 18-20 days; and 1 year. Follicles cultured in the presence of fetal calf or 12-14-day rat serum showed no morphological change after 2 days of culture. Follicles cultured in the presence of 18-20 day serum or adult serum for 2 days showed greatly altered morphology, the dermal papilla degenerated, keratinization of hair cells occurred, and an enlarged outer sheath developed. The cells in this sheath contained many filaments which were periodic acid-Schiff positive. These changes are compared with those occurring during the catagen phase of the hair cycle in vivo.

Aging↗
PubMed1979

Mural vegetations at the site of endocardial trauma in infective endocarditis complicating idiopathic hypertrophic subaortic stenosis.

In two patients infective endocarditis developed as the primary manifestation of idiopathic hypertrophic subaortic stenosis. Infected vegetations were present on the mitral and aortic valves. In addition, bacterial vegetations were observed on the septal endocardium at the site of contact between the mitral valve leaflet and the hypertrophic septum. Thus, chronic endocardial trauma, a common finding in idiopathic hypertrophic subaortic stenosis, may provide a fertile nidus for the development of bacterial vegetation.

Aged↗
PubMed1979

Rapid removal of acid from glycol methacrylate for improved histological embedding.

A method for the rapid and complete removal of methacrylic acid from commercial samples of glycol methacrylate is presented. It entails conversion of the acid to an insoluble N-acylurea by treatment with an equivalent amount of N,N'-dicyclohexylcarbodiimide. Sections of tissue embedded in polymer prepared from the purified monomer can be stained with basic dyes without simultaneously staining the polymer.

Acrylates↗
PubMed1976

Location of a high-sulphur protein in developing wool follicles using peroxidase-labelled antibody.

Antiserum to a high-sulphur protein (SCMK-B2) from wool was purified to obtain the immunoglobin G fraction, and this was labelled with horse-radish peroxidase. The labelled antibody was then applied to sections of sheep skin embedded in glycol methacrylate in order to locate the distribution of high-sulphur protein within the lower hair shaft. Regions containing the highest concentration of high-sulphur protein were the cuticle of the hair shaft and the keratogenous zone of the cortex.

Animals↗