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Biomedical subjects

P B Loder

Publications and source records attributed to P B Loder.

At least 19 recordsLinked to original sources
PubMed1996

Transperineal repair of symptomatic rectocele with Marlex mesh: a clinical, physiological and radiologic assessment of treatment.

BACKGROUND: The aim of this study was to evaluate the operative repair of rectoceles in a defined group of women by a technique designed to deal with the cause (failure of the rectovaginal septum) rather than the effect (rectal and vaginal wall bulging). STUDY DESIGN: Only women whose defecation was aided by vaginal digitation and who had large rectoceles on proctography were included. Any other clinical symptoms in the absence of vaginal digitation, even when proctography demonstrated a rectocele, were not taken as indicators for surgery in this study. There were nine women, median age 50 years (range, 32 to 61). The rectovaginal septum was repaired with Marlex mesh through a perineal approach by one surgeon. The median follow-up period was 29 months. RESULTS: Eight of the nine women achieved successful evacuation after surgery without the need for vaginal digitation. Rectocele size, depth, and the percent of barium trapped in the rectocele on proctography were all improved. Anorectal physiology measurements were unchanged by surgery. CONCLUSIONS: Operative repair of the rectovaginal septum removes the need for vaginal digitation in most women with large rectoceles on proctography. Further studies in well-defined groups of women are needed to establish how well rectocele repair aids women with a variety of other pelvic and perineal symtoms.

Adult↗
PubMed1995

Trephine colostomy: a warning.

A case of trephine colostomy is presented in which air insufflation incorrectly identified the distal limb. Disaster was averted by correct identification at laparotomy. The probable cause of the error and methods of avoidance are discussed.

Colostomy↗
PubMed1994

Haemorrhoids: pathology, pathophysiology and aetiology.

Haemorrhoidal disease is the consequence of distal displacement of the anal cushions, which are normal structures with an important role in continence. The causes of haemorrhoidal disease are unknown; constipation and abnormal bowel habit are commonly blamed despite largely contrary evidence. The most consistently demonstrated physiological abnormality is an increased maximum resting anal pressure. Most evidence points to this being a secondary phenomenon rather than the cause of haemorrhoidal disease. Among the many unexplored areas are the function of the longitudinal muscle in relation to haemorrhoidal disease, the description and pharmacological responsiveness of the anal subepithelial muscle, and the clinical role of specific pharmacological agents that might reverse some of the observed physiological changes.

Anal Canal↗
PubMed1994

'Reversible chemical sphincterotomy' by local application of glyceryl trinitrate.

Nitric oxide has emerged as one of the most important neurotransmitters mediating internal anal sphincter relaxation. The effect of glyceryl trinitrate, a nitric oxide donor, on anal tone was examined. Maximum resting pressure, predominantly a function of the smooth muscle internal anal sphincter, was measured before and 20 min after application of 0.2 per cent glyceryl trinitrate ointment in ten patients. Pressure decreased by a mean of 27 per cent (95 per cent confidence interval 18-36 per cent) (P = 0.0004) after administration of the drug. A further 20 patients were then randomized to either active or placebo ointment. Anal pressure was significantly decreased (P = 0.002) in those who received 0.2 per cent glyceryl trinitrate, but there was no significant reduction in the control patients. Mild headache occurred in two patients who were given the active preparation and in one who received placebo. Manometry was repeated 9h after application of glyceryl trinitrate and showed a sustained decrease in pressure in two patients. Topical glyceryl trinitrate may have a role in the treatment of anal fissure, haemorrhoids, certain types of constipation and anal pain. It may also reduce injury to the internal sphincter during peranal operations.

Administration, Topical↗
PubMed1994

Vaginal endosonography. New approach to image the undisturbed anal sphincter.

PURPOSE: Although anal endosonography provides clear images of anal sphincters, the probe in the anal canal may distort epithelial structures and sphincter muscles may be compressed, producing inaccurate muscle thickness measurements. The aim of this study is to describe a new approach using vaginal endosonography to image the anal canal undistorted. METHODS: Twenty females (10 healthy volunteers and 10 with fecal incontinence) had both anal and vaginal endosonography performed. RESULTS: The undisturbed anorectum, submucosa, anal cushions, and anal sphincter muscles were clearly visualized by vaginal endosonography, and anatomy was described. Although anal and vaginal endosonographic measurements of internal sphincter muscle thickness correlated (r = 0.83; P = 0.01), anal endosonography consistently underestimated the thickness (2.3 +/- 0.5 vs. 3.2 +/- 1.2 mm; mean +/- standard deviation). Anterior internal and external anal sphincter defects were identified accurately with both techniques. CONCLUSIONS: Vaginal endosonography is a new technique that enables accurate imaging of anal sphincters and epithelial structures at rest. In addition to making the diagnosis of anal sphincter defects, it has potential applications in the imaging of anovaginal sepsis and malignancy and possibly in understanding the pathogenesis of anal fissure and hemorrhoids.

Adult↗
PubMed1990

What rate of infusion of intravenous nutrition solution is required to stimulate uptake of amino acids by peripheral tissues in depleted patients?

We examined the effect of varying the quantities (0, 0.1, 0.2, 0.3, and 0.4 gN.kg-1.[day]-1) of nitrogen input on N balance, 3-methylhistidine (3MH) excretion, plasma amino acid concentration and the net flux of amino acids across the leg in depleted patients requiring parenteral nutrition. The calorie-to-nitrogen ratio was 140 to 1 (kcal:1 gN) and consequently the patients received varying amounts of calories (8, 14, 28, 42, and 56 kcal.kg-1.[day]-10. There was negative nitrogen balance and net loss of amino acids from the limb during fasting. An infusion of 0.2 gN.kg-1.[day]-1 of IVN reversed the net catabolic process and resulted in equilibrium of peripheral total amino acid flux and of tyrosine flux without a decrease in 3MH excretion. Net uptake of total amino acids and tyrosine in peripheral tissues was achieved with 0.4 gN.kg-1.[day]-1 and 56 kcal.kg-1.[day]-1. This was associated with a fivefold increase in 3MH excretion (p less than 0.01), indicating that net anabolism occurred with increased protein turnover. Fifty per cent of the amino acids taken up by peripheral tissues during infusions of 0.4 gN.kg-1.[day]-1 was due to the uptake of glutamate (Glu) and 20% was due to the uptake of branched chain amino acids (BCAA). Plasma Glu concentration, [Glu], did not increase with increasing IVN infusion, but BCAA concentrations did. Although the mean plasma [Glu] did not change with IVN infusion, there was an independent effect of plasma [Glu] (p less than 0.0001) and of N input (p less than 0.0001) on Glu flux, indicating that even at high infusion rates the maximal capacity of peripheral tissues to take up Glu had not been reached.

Amino Acids↗
PubMed1989

Validity of urinary urea nitrogen as a measure of total urinary nitrogen in adult patients requiring parenteral nutrition.

The validity of the urinary urea nitrogen (UUN) estimate of total urinary nitrogen (TUN) was tested in patients who required iv nutrition. UUN and TUN were determined in 120 urine collections from ten preoperative, 13 postoperative, and 11 stressed patients. The relationship between TUN and UUN was examined by linear regression, and analysis of covariance was used on log-transformed data to assess differences between the patient groups. Although there was a close relationship between UUN and TUN for the preoperative patients (r2 = .94, total range of differences = 3.85 g N), this was not as accurate in postoperative and stressed patients (r2 = .69 and .76, respectively, total range of differences = 16.8 and 10.7 g N, respectively). There was no significant difference between the slopes of the regression lines for the relationship between UUN and TUN for three groups (f = 1.1, df = 2114, p less than .3), but the intercepts of the regression lines differed between the preoperative and stressed patient groups (t = 3.47, v = 114, p less than .001). The relationship between TUN and UUN for the whole group was improved by the inclusion of the independent variables of both the patient's clinical state and the urinary creatinine excretion. Arm muscle circumference, which is an estimate of muscle mass, may replace creatinine excretion with little loss in prediction accuracy.

Adult↗
PubMed1987

A randomised comparison of three drainage systems following cholecystectomy.

The efficacy of low pressure, high pressure and passive drainage systems have been compared after cholecystectomy. Symptoms of pain, discomfort and nausea were compared using linear analogue scales and spirometry was used to examine pre-operative and postoperative respiratory function. The low pressure suction drain removed an intraperitoneal marker, gentamicin, more effectively than the high pressure suction drain, but not more effectively than the passive drain. There were no differences in postoperative respiratory function nor in the amount of pain or discomfort between the groups. The passive drain group reported less nausea than the suction drain groups. If a negative pressure drainage system is to be used, a low pressure suction drain should be used in preference to a high pressure system.

Cholecystectomy↗
PubMed1971

Isolation and nature of intracellular peptides from a cephalosporin C-producing Cephalosporium sp.

1. Three peptides containing alpha-aminoadipic acid and cysteine have been obtained in small amounts from the mycelium of a Cephalosporium sp. 2. The peptides were precipitated as cuprous mercaptides together with glutathione and resolved from the latter and from each other by preparative paper electrophoresis and chromatography either in the sulphonic acid form or as S-sulphonyl derivatives. From the S-sulphonyl derivatives they were obtained in the thiol form. 3. One peptide (P3) was shown by amino acid analysis and the mass spectrum of the NS-ethoxycarbonyl derivative of its methyl ester to be delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine. A second peptide (P2) contained alpha-aminoadipic acid, cysteine, valine and glycine, and the third peptide (P1) contained alpha-aminoadipic acid, cysteine, beta-hydroxyvaline and glycine.

Acremonium↗
PubMed1971

Biosynthesis of peptides containing -aminoadipic acid and cysteine in extracts of a Cephalosporium sp.

1. Three intracellular peptides found in small amount in a Cephalosporium sp. were rapidly labelled when dl-[(14)C]valine was added to a shaken suspension of the organism. More (14)C was incorporated into peptide P3, delta-(l-alpha-aminoadipyl)-l-cysteinyl-d-valine, than into peptide P2 (containing alpha-aminoadipic acid, cysteine, valine and glycine) or peptide P1 (containing beta-hydroxyvaline in place of the valine in peptide P2). 2. Peptides P3 and P2, but not peptide P1 were formed in a broken-cell system from the Cephalosporium sp. in the presence of delta-(l-alpha-aminoadipyl)-l-cysteine and dl-[(14)C]valine. No synthesis was observed in the presence of delta-(d-alpha-aminoadipyl)-l-cysteine or of dl-alpha-amino[(14)C]adipic acid and l-cysteinyl-l-valine or l-cysteinyl-d-valine. 3. The biosynthesis of these peptides was catalysed by the particulate fraction of the broken-cell system, whereas that of glutathione was catalysed by the supernatant fraction. 4. These results are discussed in relation to penicillin N and cephalosporin C biosynthesis.

Acremonium↗
PubMed1969

Behaviour of alpha-aminoadipylcysteine and glutamylcysteine in the presence of intact and disrupted mycelium of a Cephalosporium sp.

1. delta-(l-alpha-Aminoadipyl)-l-cysteine, the corresponding d- and dl-alpha-aminoadipyl isomers, delta-(dl-alpha-amino[6-(14)C]adipyl)-l-cysteine and gamma- and alpha-l-glutamyl-l-cysteine were synthesized. 2. The behaviour of delta-(l-aminoadipyl)-l-cysteine and the corresponding d- and dl-alpha-aminoadipyl isomers was studied in the presence of suspensions of intact mycelium of a Cephalosporium sp., suspensions treated ultrasonically and extracts obtained by grinding with alumina. 3. With intact mycelium the l-alpha-aminoadipyl isomer was removed more rapidly from the extracellular fluid than the corresponding d-isomer. 4. Addition of delta-(dl-alpha-amino[6-(14)C]adipyl)-l-cysteine to suspensions of intact mycelium led to the labelling of extracellular and intracellular penicillin N and cephalosporin C, but also to extensive hydrolysis of the dipeptide. 5. Broken-cell systems hydrolysed delta-(l-alpha-aminoadipyl)-l-cysteine and the corresponding d-alpha-aminoadipyl isomer, but the former was hydrolysed more readily than the latter. 6. gamma- and alpha-l-Glutamyl-l-cysteine were also hydrolysed but delta-(l-alpha-aminoadipyl)-l-cysteinyl-l-valine was not. 7. Only part of the enzyme activity in broken-cell systems responsible for the hydrolysis of delta-(alpha-aminoadipyl)-l-cysteine was present in the supernatant obtained on centrifugation at 20000g. 8. Possible implications of these findings are discussed.

Acremonium↗
PubMed1968

Measurement of three antibiotics (penicillin, cephalothin, and chloramphenicol) when present together in mixtures.

Benzylpenicillin, cephalothin, and chloramphenicol were measured individually and quantitatively when present together in mixtures at concentrations found in patients. The assay depended on the selective inactivation of two of the antibiotics, permitting the third to be assayed as if present alone. Agar seeded with a chloramphenicol-resistant, penicillinase-negative Staphylococcus aureus was used for a cylinder-plate assay of appropriately diluted fluid to determine the activity of either benzylpenicillin or cephalothin after either beta-lactamase inactivation of the former or ultraviolet light inactivation of the latter. Chloramphenicol was assayed with Sarcina lutea after appropriate beta-lactamase inactivation of both cephalothin and benzylpenicillin. Fluids containing various amounts of the three antibiotics were assayed by this method with less than 8% error. Procedures that fail to measure each antibiotic individually may give larger errors.

Biological Assay↗
PubMed1968

Enhancing effect on alkalinization of the medium on the activity of erythromycin against gram-negative bacteria.

The antibacterial activity of erythromycin was markedly enhanced by alkalinization of the culture medium or urine within the clinical range (pH 6.0 to 8.2). This effect was demonstrated against recent isolates of Escherichia coli, Klebsiella pneumoniae, Enterobacter sp., and Pseudomonas aeruginosa, as well as against Staphylococcus aureus and Streptococcus faecalis. The urine of normal volunteers was made alkaline by ingestion of sodium bicarbonate or acetazolamide (Diamox) during administration of 1.0 g of erythromycin every 8 hr; such urine was capable of inhibiting E. coli and K. pneumoniae even when diluted up to (in one instance) 128 times with broth of the same pH as the urine. Undiluted urine of the same subjects, without alkalinization, was seldom capable of inhibiting these organisms. The range of pH (6.6 to 8.6) over which the antibacterial effect was enhanced coincided with that over which there was decreasing ionization of a basic group.

Bacteria↗