Biomedical subjects
Publications and source records attributed to H S Lam.
Four cases of emphysematous pyelonephritis are reported and the pathogenesis, surgical implications and preferred mode of management are discussed. We have not found percutaneous drainage to be useful, but feel there is an important place for surgical drainage alone because of the potential for renal recovery and the risks of emergency nephrectomy.
The use of stone surface area measurements obtained from standard radiographs provides a more accurate and reproducible assessment of stone burden when reporting results and treatment recommendations for staghorn calculi. Techniques for determining stone surface area include use of graph paper, planimeter or computerized image analysis. The use of graph paper is inefficient while planimeters suffer from significant variation for areas less than 500 mm.2 (more than 5%). Computer image analysis is accurate, rapid and easiest to perform. Software programs compatible with microcomputers are readily available making assessment of stone surface area practical and inexpensive. Stone surface area showed close correlation to stone volume as measured by 3-dimensional computerized tomography (correlation coefficient 0.84, p = 0.005). Stone surface area determination enables more accurate reporting of treatment results and, thus, recommendations based upon stone burden. Comparison of data between institutions becomes more meaningful if stone surface area is used. Stone surface area also provides a useful basis to study and compare trends of treatment within a single institution.
Percutaneous nephrostolithotomy with or without extracorporeal shock wave lithotripsy (ESWL) has been extensively used in the management of staghorn calculi, with stone-free rates varying from 23 to 86%. Explanations for the variability of such results include differences in stone burden, differences in percutaneous techniques and an overreliance on ESWL. The results and changing trends in the relative roles of percutaneous nephrostolithotomy and ESWL in the management of staghorn calculi at the Methodist Hospital of Indiana were examined. We reviewed 343 cases of staghorn calculi (partial and complete) with adequate followup data, which were managed with initial percutaneous nephrostolithotomy. Cases were divided into 2 groups: group 1 (252 cases) from 1984 to 1987 when access was performed by a radiologist and group 2 (91 cases) from 1988 to 1990 when access was performed by a urologist. Although stones in group 2 tended to be larger, a decreasing dependence on ESWL was noted (64.7% in group 1 compared to 35.2% in group 2, p less than 0.001). Despite the larger stone size in group 2, stone-free rates were similar (83.3% in group 1, 86.8% in group 2). In groups 1 and 2 percutaneous nephrostolithotomy alone achieved stone-free rates of 91% and 91.5%, respectively. The stone-free rate with the combination approach was 79.1% and 78.1% in groups 1 and 2, respectively. Technical refinements with percutaneous nephrostolithotomy in group 2 include accurate and carefully selected accesses (superior pole in 36.3%) for best approach to the stone, multiple accesses (13.3%) and improved skills in flexible nephroscopy. Blood transfusion has not been required in group 2 compared with 11.1% in group 1. Mean hospital stay was 12.4 days in group 1 and 10.3 days in group 2 (percutaneous nephrostolithotomy alone, 7.2 days). With careful attention to percutaneous nephrostolithotomy techniques, complex renal stones can be successfully managed endourologically, reducing the need for combination ESWL. Complications previously associated with percutaneous nephrostolithotomy have decreased.
Treatment recommendations and results reported for the management of staghorn calculi are highly variable. In an attempt to provide a more objective means to compare treatment results for staghorn renal calculi, stone burden as measured by stone surface area was used. Stone surface area was determined by computer analysis. A total of 380 cases of staghorn calculi treated at the same institution was evaluated. Treatment consisted of initial percutaneous nephrostolithotomy with or without extracorporeal shock wave lithotripsy (ESWL*) in 298 cases and ESWL monotherapy in 82. When considered as a group, the overall stone-free rate for initial percutaneous nephrostolithotomy (mean surface area 1,378.3 mm.2) was 84.2% compared to 51.2% (p less than 0.0001) for ESWL monotherapy (mean surface area 693.4 mm.2). For staghorn calculi smaller than 500 mm.2 a stone-free rate of 94.4% was achieved in the percutaneous nephrostolithotomy with or without ESWL group compared to 63.2% for ESWL monotherapy (p = 0.0214). For calculi of 501 to 1,000 mm.2 the stone-free rates were 86% and 45.7%, respectively (p less than 0.0001). When stone surface area exceeded 1,000 mm.2 the stone-free rate for percutaneous nephrostolithotomy with or without ESWL was 82.4% but it was only 22.2% for ESWL monotherapy (p = 0.0002). Overall, when adjusted for stone surface area the odds of being stone-free were more than 8 times higher for initial percutaneous nephrostolithotomy versus ESWL monotherapy (odds ratio = 8.36, p less than 0.0001). While percutaneous nephrostolithotomy with or without ESWL appears to be the procedure of choice for most staghorn stones, ESWL monotherapy may have a role for some stones smaller than 500 mm.2. In 12 such cases associated with a nondilated renal collecting system (mean surface area 380.5 mm.2) a stone-free rate of 91.7% was achieved. The number of procedures required to complete therapy was higher in the initial percutaneous nephrostolithotomy group (2.8 versus 2.1, p less than 0.0001). Although complications were more common in the ESWL monotherapy group (manifested as obstruction in 30.5%), bleeding requiring blood transfusion was more frequent in the initial percutaneous nephrostolithotomy group (9.4%).
An interesting case of bifid blind-ending ureter occurring in a young Indian girl is reported. She presented with severe recurrent right iliac fossa pain for which she underwent appendicectomy which did not resolve her symptoms. Subsequent urological investigation--IVU and retrograde pyeleogram--revealed the genuine diagnosis. Surgical excision of the blind-ending branch was successful in relieving the intractable pain. A review of the literature on this uncommon congenital urological problem is outlined stating its clinical significance and treatment options.
This report deals with a father and his son who developed acute renal failure following multiple bee stings. The renal lesion in these patients appears to be due to rhabdomyolysis caused by the bee venom. The other mechanisms are also discussed. The need for clinicians to be aware of acute renal failure as a complication of bee stings is stressed.
This article describes the development of a computer-based system for the prospective collection of data for surgical audit and peer review with the generation of a surgical discharge letter. The software has been developed for an IBM personal computer and is suitable for any compatible computer. The system has potential advantages for teaching hospitals as it enables patients to obtain a definitive discharge letter on their discharge from hospital. It is also of potential benefit to surgeons who wish to collect clinical data and to audit the quality of their surgical practice.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A FORTRAN computer program is described which enables solution of a set of partial differential equations describing synaptic transmission, including neurotransmitter diffusion, binding to receptors on the postsynaptic membrane with subsequent formation of open ion-conducting channels, and hydrolysis. Integration is performed with a widely available package (PDETWO), and flexibility is achieved through use of 6 user-specified routines. The reliability of solution was checked by comparison with an analytic solution for a diffusion-only model. Application of the program is illustrated with an analysis of miniature endplate current rise times.
Neuromuscular blocking agents are widely used in anaesthesia, and a simple quantitative method of monitoring their effects is desirable. This paper describes a new instrument which has been developed for electromyographic monitoring of neuromuscular block by a non-invasive technique which is both reliable and easy to use. The median nerve is stimulated at the wrist and the electromyogram (e.m.g.) from a thenar muscle is detected, rectified and integrated electronically to produce a meter display of the assessment of block. The method is recommended for routine use.
There exists a good correlation between the measured electrical activities and isometric twitch tension in the cat soleus muscle during synchronous stimulation. For an unbiased sampling of electrical activities by averaging a number of electromyograms over the muscle concerned, a relation of the form E = 0.98T + 5.35 has been established. It is hoped that this relation will prove valuable in clinical application where EMGs are used. Electrode types for EMG pick-up differ in terms of the signal recorded due to the difference in the spatial and temporal addition of individual motor unit firing and the constructional difference of the electrodes. Fine wire pairs are the best for linearity and ease of application. Whe surface electrodes are used because of their non-invasive nature, care must be exercised to established the exact relation between EMG and tension. EMG recordings from different sites within a muscle show considerable variation. A more reliable measure can be obtained by external averaging of multiple pairs of electrodes.
The effect of hypothermia on the action of d-tubocurarine (d-TC) was studied under carefully controlled experimental conditions. It was found that with computer controlled infusion, 60% less d-TC was required to sustain 75% muscle paralysis in cats, during steady-state, in vivo, when the temperature was changed from 37 degrees C to 30 degrees C. The corresponding relaxant consumption rates were 0.136 +/- 0.025 and 0.055 +/- 0.012 mg/kg/1/2 hr respectively. When there was no temperature change the maintenance dosage of d-TC remained constant for up to four hours denoting the equilibrium phase of the relaxant kinetics. Temperature transitions introduced dynamic changes in these kinetics and altered the constancy of the maintenance dosage.