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Biomedical subjects

P Knight

Publications and source records attributed to P Knight.

At least 55 records · Page 3Linked to original sources
PubMed1984

Reducing the risk of wound infection in operations upon the colon.

One hundred and forty-seven patients undergoing elective colonic operations during a 30 month period were studied. The over-all wound infection rate was 6.8 per cent. Thirty-seven patients had subcutaneous drains used and, in none, did a wound infection develop. The incidence of wound sepsis in the remaining patients was 9.1 per cent. Wicks appear to be of benefit in reducing the incidence of wound infections in elective colonic operations.

Adenocarcinoma↗
PubMed1983

Evaluation of basket and paddle dissolution methods using different performance standards.

Dissolution studies using both basket and paddle methods were carried out to evaluate two prednisone standards. Results of the experiments showed that the USP prednisone calibrator is sensitive to perturbations by the basket method but not to perturbations by the paddle method. However, the National Center for Drug Analysis (NCDA) prednisone performance standard is sensitive to perturbations by the paddle method but not to perturbations by the basket method. These results suggest that no single standard can predict the suitability of the dissolution equipment by the basket and paddle methods.

Evaluation Studies as Topic↗
PubMed1983

The middle thyroid vein: an alternate route for central venous catheter insertion.

The technique for using the middle thyroid vein to insert infant central venous nutrition catheters is described. The middle thyroid vein is an alternate route of access to the central circulation when attempts to insert a central catheter through the external jugular vein are unsuccessful. Seventy percent of infants (11:16) had successful cannulations of their central venous circulation through the middle thyroid vein.

Catheterization↗
PubMed1982

TRH concentration in rat olfactory bulb is undiminished by deafferentation.

The effect of deafferentation of the rat olfactory bulb on bulbar TRH concentration was studied. TRH concentrations in the lesioned bulbs did not decline when compared to concentrations in sham-lesioned bulbs for the post-lesion intervals of 1 h through 14 days. Since TRH concentrations did not decline following deafferentation, TRH in the olfactory bulb does not derive from centrifugal neurons.

Afferent Pathways↗
PubMed1982

Thiazides IV: Comparison of dissolution with bioavailability of chlorothiazide tablets.

Based on the initial dissolution rate profiles in water, a slow-dissolving, an intermediate-dissolving, and a fast-dissolving chlorothiazide 250-mg tablet were selected for the bioavailability and bioequivalence study. In addition, two marketed 500-mg chlorothiazide tablets were studied. The three 250-mg tablets were bioequivalent, as were the two 500-mg tablets. Therefore, the dissolution test conditions were modified to associate in vitro dissolution with in vivo performance of the product. Based on these results, it was concluded that a dissolution of 75% in 60 min by paddle method at 75 rpm in pH 7.4 phosphate buffer can be used as a quality assurance test for 250- and 500-mg chlorothiazide tablets.

Biological Availability↗
PubMed1980

Pyomyositis tropicans: a diagnostic dilemma.

Pyomyositis tropicans is a rare disease in non-tropical climates and thus presents diagnostic difficulties. Two children with single staphylococcal psoas muscle abscesses were recently successfully treated. Computerized axial tomography was found to be a useful diagnostic aid, allowing exact localization of the lesion. The diagnosis and therapy of these abscesses are discussed.

Abscess↗
PubMed1980

Investigation, by cross-linking, of conformational changes in F-actin during its interactions with myosin.

The hypothesis that the subunits of F-actin rotate during interactin with myosin and ATP has been tested by using the specific cross-linking reagent p-phenylene-N,N'-bis(maleimide) (PM). The insertion of cross-links between F-actin subunits does not change the ability of the F-actin to activate the ATPase of either myosin subfragment-1 (S-1) or heavy meormyosin, and its ability to superprecipitate with myosin is unimpaired. We conclude that large-scale rotations of actin subunits are not required for activity. The cross-linking of F-actin by PM is, however, inhibited in a noncooperative fashion by S-1 binding, suggesting that a small local change in actin structure may accompany the binding of S-1 or that S-1 sterically blocks the cross-linking by binding near the contact region between actin subunits.

Actins↗
PubMed1980

The use of levarterenol and phentolamine in patients with low cardiac output following open-heart surgery.

A study was made of the hemodynamic effects of levarterenol and phentolamine in patients in whom low cardiac output developed following open-heart operation. After the patients were weaned from cardiopulmonary bypass, the inotropic agents were infused into an external or internal jugular vein through an IVAC pump. Levarterenol was administered first until systolic arterial pressure rose 20 to 30% above the higest recorded preoperative pressure. After stabilization, phentolamine was administered, and infusion rates were adjusted so that arterial blood pressure was returned to levels measured before bypass. After infusion, all patients showed an increase in cardiac index, mean arterial pressure, mean stroke volume index, and left ventricular stroke work index. Mean pulmonary artery pressure, pulmonary vascular resistance, and left atrial pressure decreased in all patients. This study demonstrates that hemodynamic improvement occurs in humans in low cardiac output state with simultaneous infusion of levarterenol and phentolamine. We recommend these agents for use in patients with low output, unless they continue to receive propranolol during and after operation. Patients on a regimen of propranolol should not be given levarterenol and phentolamine.

Blood Pressure↗
PubMed1980

Evaluating students in family medicine using simulated patients.

Various techniques have been used to evaluate students in family medicine clerkships and electives. Multiple choice or essay questions have been used extensively but are not satisfactory in testing some of the affective areas considered important for future family physicians. At Southern Illinois University School of Medicine, the Department of Family Practice has evolved an evaluation system using simulated patients as well as traditional methods. Simulated patients have proved to be an excellent means of evaluating affective skills which are not easily tested by other techniques.

Clinical Competence↗
PubMed1979

Hydrolysis of p-NN'-phenylenebismaleimide and its adducts with cysteine. Implications for cross-linking of proteins.

To understand the extent of the cross-linking of proteins by the bifunctional reagent p-NN'-phenylenebismaleimide, a quantitative study of competing reactions has been undertaken. The two reactive maleimide rings of the bismaleimide are hydrolysed in mildly alkaline aqueous solutions much more rapidly than is the single maleimide ring of the monofunctional analogue N-ethylmaleimide. The kinetics of hydrolysis are second-order, depending on both imide and hydroxyl ion concentration in the pH range 8-10. The hydrolysis of the first imide ring of the bismaleimide is more rapid than the second, with second-order rate constants of 1600 M-1 . s-1 and 500 M-1 . s-1 respectively, at 25 degrees C. The half-times for hydrolysis of the first and second imide rings at pH 9.0 are therefore only 43s and 140s. Because it renders the maleimide ring unreactive towards cysteine, this rapid hydrolysis can limit the extent of cross-linking of proteins by the bismaleimide.

Chemical Phenomena↗
PubMed1978

p-NN'-phenylenebismaleimide, a specific cross-linking agent for F-actin.

Covalent cross-links can be inserted between the subunits of F-actin by using p-NN'-phenylenebismaleimide. Cross-linking reaches its maximum value when one molecule of reagent has reacted with each actin subunit. p-NN'-Phenylenebismaleimide reacts initially with a cysteine residue on one subunit, the slower cross-linking reaction involving a lysine residue on a neighbouring subunit. Hydrolysis of the actin-bound reagent limits the extent of cross-linking. Quantitative analysis of the amounts of cross-linked oligomers seen on polyacrylamide gels containing sodium dodecyl sulphate suggests that neither the binding of the reagent to actin nor the formation of cross-links introduces strain into the structure. The cross-links do not join together different F-actin filaments, and evidence is presented that suggests that the cross-links join subunits of the same long-pitched helix.

Actins↗
PubMed1977

The arm circumference at birth and its relations to other anthropomeric parameters.

The weight, head, chest and arm circumference of four hundred and sixty-one infants in Jamaica were measured during the first twenty-four hours of birth. The purpose of this work was to draw attention to the arm circumference as a possible indicator of the stage of maturity at birth and correlate this parameter against the other three and against factors on the mother. The highest positive correlation was found between the weight and the chest circumference, followed by the weight and arm cirucmference. Attempt to produce an equation to estimate birth weight from arm and chest circumference was unsatisfactory.

Anthropometry↗
PubMed1973

Reactions to tetanus toxoid.

In a factory population the occurrence of reactions to tetanus toxoid was recorded after 6740 injections. The incidence of general reactions was 0.3% and of local reactions 2.6%. The local reaction rate to the first injection of the basic immunization course was 0.9%, to the second injection 2.7%, and to the third injection 7.4%. To booster injections the rate was 1.6%. The local reaction rate was appreciably higher in women than in men - 14.4% and 5.7% respectively in the case of the third injection - and the incidence among women increased with age.Tetanus vaccine containing 10 Lf of toxoid caused fewer reactions than one containing 20 Lf, but a reduction in the content of aluminium adjuvant did not affect the reaction rate.Almost all reactors were found to have a satisfactory serum antitoxin concentration at the time of the reaction or developed a satisfactory immunity within 1-6 months.Skin tests were made in 32 hypersensitive patients. Neither the diluent, thiomersal preservative, nor the culture medium appeared to be responsible for hypersensitivity. The degree of hypersensitivity elicited by a special highly purified toxoid was only very slightly less than that elicited by the commercially pure toxoid. It is suggested that reactions are largely due to the toxoid antigen itself rather than to impurities or other components of the vaccine.

Adjuvants, Immunologic↗