Malone antegrade continence enema for adults with neurogenic bowel disease

PURPOSE

We describe the outcomes of adults with neurogenic bowel disease who underwent a Malone antegrade continence enema procedure with or without concomitant urinary diversion.

MATERIALS AND METHODS

Consecutive adult patients with neurogenic bowel disease who underwent an antegrade continence enema procedure (continent catheterizable appendicocecostomy for fecal impaction) were retrospectively reviewed.

RESULTS

Of the 7 patients who underwent an antegrade continence enema synchronous urinary procedure (ileal conduit, augmentation ileocystoplasty with continent catheterizable abdominal stoma or augmentation ileocystoplasty) was also performed in 6. Mean patient age was 32 years and mean followup was 11 months. Of the 7 patients 6 who self-administered antegrade continence enemas regularly were continent of stool per rectum and appendicocecostomy, using the appendicocecostomy as the portal for antegrade enemas. All 6 compliant patients reported decreased toileting time and improved quality of life. Preoperative autonomic dysreflexia resolved postoperatively in 3 patients. All urinary tracts were stable. In 4 patients 5 complications occurred, including antegrade continence enema stomal stenosis requiring appendicocutaneous revision (1), antegrade continence enema stomal stenosis requiring dilation (1), superficial wound infection (1), small bowel obstruction requiring lysis of adhesions (1) and urinary incontinence (1 who underwent continent urinary diversion).

CONCLUSIONS

Patients with neurogenic bladder and bowel disease may benefit from antegrade continence enema performed synchronously with a urinary procedure. Antegrade continence enema may be indicated alone for neurogenic bowel. Patient selection is important.

Malone antegrade continence enemas for autonomic dysreflexia secondary to neurogenic bowel

A 42-year-old man with T-4 ASIA B thoracic paraplegia presented with chronic constipation, fecal incontinence, and bowel-related autonomic dysreflexia (AD) refractory to conservative bowel program. His usual toileting time lasted one to five hours. Antegrade continence enemas (ACE) were performed. The ACE technique, which requires creating a continent catheterizable appendicocecostomy, is described. Postoperatively, a daily enema was given through the stoma. The patient's toileting time was reduced to 20 minutes and his AD resolved. The role of the ACE is discussed in adult spinal cord injury (SCI).

Visual search for motion-in-depth: stereomotion does not 'pop out' from disparity noise

In a visual search task, targets defined by motion or binocular disparity stand out effortlessly from stationary distractors ('pop-out'), suggesting that target and distractors are processed by different neural mechanisms. We used pop-out to explore whether motion directly toward or away from the observer (z-motion) is detected using binocular motion cues. A target moving laterally (x-motion) popped out amid stationary distractors with binocular disparity, but z-motion did not pop out. However, a small x-motion added to the target's z-motion caused it to pop out. We therefore suggest that the visual system may not be specifically sensitive to binocular motion differences.

Demand management: another marketing tool or a way to quality care?

Demand management tools are population-based strategies used to control costs and improve utilization of services by assisting health consumers in maintaining their health and seeking appropriate health care. These tools are increasingly used by health care delivery systems and, in the US, by fiscal intermediaries, such as insurance companies. If these tools are not properly applied, there is a clear possibility that their use may lead a reduction of health care services with no improvement in clinical, humanistic, or economic outcomes. Demand management effectiveness has not been rigorously examined by the medical industry or academia. Before adopting or purchasing demand management technologies, health care systems should examine them carefully to determine how the tools were developed and who they were intended to serve. Once implemented, careful tracking of population outcomes is as necessary with these technologies as with any other technologies that can affect health care.

Holmium:YAG percutaneous nephrolithotomy: the laser incident angle matters

PURPOSE

Laser physics dictate that maximal radiant exposure occurs when the laser strikes the target at a normal incidence. Since the renal collecting system often limits nephroscope movements during percutaneous nephrolithotomy, the laser-calculus incidence angle may vary. We have observed during holmium:YAG percutaneous nephrolithotomy that the side firing fiber more easily approaches a normal incidence compared to the end firing fiber. We test the hypothesis that holmium:YAG percutaneous nephrolithotomy is faster with a side firing fiber compared to an end firing fiber.

MATERIALS AND METHODS

Consecutive holmium:YAG percutaneous nephrolithotomy cases were studied retrospectively. The calculus size and composition, surgical time, fragmentation speed (size/time) and stone-free rates were compared between 11 patients treated with end and 8 treated with side firing fibers.

RESULTS

When the end and side firing groups were compared, calculus sizes (mean plus or minus standard deviation) were 22 +/- 13 versus 48 +/- 17 mm. (p = 0.004), calcium oxalate monohydrate incidence was 55 versus 75% (p = 0.3), surgical times were 168 +/- 87 versus 124 +/- 51 minutes, computed fragmentation speeds were 0.15 +/- 0.09 versus 0.43 +/- 0.15 mm. per minute (p = 0.0009) and stone-free rates were 73 versus 88% (p = 0.4), respectively.

CONCLUSIONS

The side firing fiber is faster than the end firing fiber for holmium:YAG percutaneous nephrolithotomy. These results are consistent with principles of laser physics.

Surface characterization of biomedical materials by measurement of electroosmosis

This paper reviews recent studies by the authors on the surface characterization of biomedically significant materials through electroosmosis determination. The surfaces studied include transparent and nontransparent materials such as quartz, ceramics, paper, and cast polymer capillaries, slides, and particles, in both native and surface modified form. The method is nondestructive, relatively fast, mechanistically simple, automatable to varying degrees, and can be used to analyze samples under physiologically compatible conditions. New experimental and mathematical modeling approaches allow estimates to be obtained with regard to the surface density and pK of various chemical groups, as well as the thickness of polymer or other surface coatings. Surface modifications which may be characterized include, covalent alteration via radiofrequency plasma discharge or organosilane grafting, noncovalent alteration via polymer adsorption, and covalent grafting of neutral polymers, such as poly(ethylene glycol) or dextran. Results complement those from other surface analysis techniques, and correlate with physiologically significant phenomena such as protein adsorption.

Carbon dioxide starvation, the development of C4 ecosystems, and mammalian evolution

The decline of atmospheric CO2 over the last 65 million years (Ma) resulted in the 'CO2-starvation' of terrestrial ecosystems and led to the widespread distribution of C4 plants, which are less sensitive to CO2 levels than are C3 plants. Global expansion of C4 biomass is recorded in the diets of mammals from Asia, Africa, North America, and South America during the interval from about 8 to 5 Ma. This was accompanied by the most significant Cenozoic faunal turnover on each of these continents, indicating that ecological changes at this time were an important factor in mammalian extinction. Further expansion of tropical C4 biomass in Africa also occurred during the last glacial interval confirming the link between atmospheric CO2 levels and C4 biomass response. Changes in fauna and flora at the end of the Miocene, and between the last glacial and interglacial, have previously been attributed to changes in aridity; however, an alternative explanation for a global expansion of C4 biomass is CO2 starvation of C3 plants when atmospheric CO2 levels dropped below a threshold significant to C3 plants. Aridity may also have been a factor in the expansion of C4 ecosystems but one that was secondary to, and perhaps because of, gradually decreasing CO2 concentrations in the atmosphere. Mammalian evolution in the late Neogene, then, may be related to the CO2 starvation of C3 ecosystems.

Dietary and environmental reconstruction with stable isotope analyses of herbivore tooth enamel from the Miocene locality of Fort Ternan, Kenya

Tooth enamel of nine Middle Miocene mammalian herbivores from Fort Ternan, Kenya, was analyzed for delta 13C and delta 18O. The delta 18O values of the tooth enamel compared with pedogenic and diagenetic carbonate confirm the use of stable isotope analysis of fossil tooth enamel as a paleoenvironmental indicator. Furthermore, the delta 18O of tooth enamel indicates differences in water sources between some of the mammals. The delta 13C values of tooth enamel ranged from -8.6(-)-13.0/1000 which is compatible with a pure C3 diet, though the possibility of a small C4 fraction in the diet of a few of the specimens sampled is not precluded. The carbon isotopic data do not support environmental reconstructions of a Serengeti-typed wooded grassland with a significant proportion of C4 grasses. This study does not preclude the presence of C3 grasses at Fort Ternan; it is possible that C3 grasses could have had a wider geographic range if atmospheric CO2 levels were higher than the present values.

Renin-angiotensin system genes in kidney development

The renin-angiotensin system (RAS) plays a key role in cardiovascular homeostasis through the interactions of angiotensin II with its receptors. All components of the RAS are developmentally regulated in the kidney. The functions of the system in the maturing kidney overlap those of the adult, but higher levels of expression and novel locations of expression in the fetus suggest that the RAS has alternate functions as well. Increasing evidence suggests that the RAS may regulate renal growth and development by initiating a complex cascade of events, involving growth factors and proto-oncogenes and other unidentified factors. These same cascades may also be important in renal disease states. Recent advances in the field of molecular and cell biology are providing new tools and strategies to elucidate the intimate mechanism whereby the RAS regulates growth processes and disease states.

The utility of ultrasonography in the evaluation of groin masses: a case report

Surgeons are often faced with the evaluation and management of groin masses. In most cases, an accurate history and physical examination will establish a diagnosis. Ultrasonography is being increasingly used in the evaluation of surgical problems. A case is presented in which bedside ultrasound was utilized in the evaluation of a large, symptomatic left inguinal mass found to be a synovial cyst on exploration. The differential diagnosis of cystic groin lesions and the impact of ultrasonography on diagnosis is reviewed with emphasis on synovial cysts. Surgeon-directed ultrasonography is an asset in the diagnosis of some patients with groin masses and may assist in the identification of those lesions requiring prompt operative intervention.

Promises and pitfalls of ensuring health care quality

On the surface, quality assurance and quality improvement appear to have similar objectives; however, the purpose of each is fundamentally different. This paper discusses these two frequently confused approaches to quality in health care, identifying the primary objective of each and clarifying which approach should be used for various situations. Past and present issues, including questions such as, "What should a health plan's role be?" and "What does the public want?" are explored using examples and study results. A California quality scoreboard project is also discussed, including the initial process of ranking plans and the difficulties encountered in attempting to publicize the data. Finally, areas of consensus and debate are addressed.

Evaluation of recurrent thrombosis and hypercoagulability

The primary mechanisms for coagulation were described more than a century ago. However, inherited disorders of coagulation have been recognized for only a few decades. Activated protein C resistance and other related protein defects account for many cases of hypercoagulability. Primary care physicians can initiate testing in individuals for whom there is a high degree of suspicion. Testing for specific disorders is best performed before initiation of anticoagulant therapy. Management often includes long-term warfarin therapy following initial anticoagulation with heparin.

Ureteroscopic management of ureteral calculi: electrohydraulic versus holmium:YAG lithotripsy

PURPOSE

This study compared electrohydraulic and holmium:YAG lithotripsy for ureteral calculi.

MATERIALS AND METHODS

Two cohorts of consecutive patients with ureteral calculi treated with ureteroscopic electrohydraulic or holmium:YAG lithotripsy were retrospectively compared. Electrohydraulic lithotripsy was done using a 1.9F fiber at energy settings between 50 and 100 v. Holmium:YAG lithotripsy was done using a 365 microm. fiber at energy settings of 0.6 to 1.5 J.

RESULTS

A total of 23 and 47 consecutive patients underwent electrohydraulic and holmium:YAG lithotripsy, respectively. For preoperative calculi less than 15 mm. mean stone size plus or minus standard deviation was 9 +/- 3 versus 9 +/- 3 mm. (p = 0.5), mean operative time was 72 +/- 21 versus 102 +/- 38 minutes (p = 0.004), stone-free rate at the end of ureteroscopy was 65 versus 97 (p < 0.01) and 3-month stone-free rate was 94 versus 97% (p = 0.4) for electrohydraulic versus holmium:YAG lithotripsy. For preoperative calculi 15 mm. or greater stone size was 19 +/- 5 versus 19 +/- 4 mm. (p = 0.9), operative time was 159 +/- 61 versus 108 +/- 27 minutes (p = 0.01), stone-free rate at the end of ureteroscopy was 33 versus 87% (p = 0.001) and 3-month stone-free rate was 67 versus 100% (p = 0.02). Complications were not significantly different in either comparison.

CONCLUSIONS

The overall likelihood that a patient would be rendered stone-free at ureteroscopy and 3 months after ureteroscopy favored holmium:YAG over electrohydraulic lithotripsy. For ureteral calculi less than 15 mm. electrohydraulic lithotripsy was more rapid than the holmium:YAG procedure but for ureteral calculi 15 mm. or greater the holmium:YAG technique was more rapid than electrohydraulic lithotripsy. The outcomes differences may have resulted from the different mechanisms of electrohydraulic and holmium:YAG lithotripsy.

Differences in costs of treatment for foot problems between podiatrists and orthopedic surgeons

We examined charge data for health insurance claims paid in 1992 for persons under age 65 covered by a large California managed care plan. Charge and utilization comparisons between podiatrists and orthopedic surgeons were made for all foot care and for two specific foot problems, acquired toe deformities and bunions. Podiatrists provided over 59% of foot care services for this commercial population of 576,000 people. Podiatrists charged 12% less per individual service than orthopedists. However, podiatrists performed substantially more procedures per episode of care and treated patients for longer time periods, resulting in 43% higher total charges per episode. Hospitalization was infrequent for all providers, although podiatrists had the lowest rates. In a managed care setting in which all providers must adhere to a preestablished fee schedule, regardless of specialty, the higher utilization by podiatrists should lead to higher overall costs. In some cases, strong utilization controls could offset this effect. We do not know if the utilization difference is due to actual treatment or billing differences. Further, we were unable to determine from the claims data if one specialty had better outcomes than the other.

Active Control of Heading and Depth

The addition of depth information has been reported to improve performance on a locomotor heading judgement task in a cloud of dots. Van den Berg and Brenner [1994 Nature (London)371 700 – 702] used stereoscopic disparity as a depth cue. Coding dots with disparity provides both cues for depth order and for identity between successive frames (each dot may be disambiguated from its 2-D neighbours by its 3-D position). Here, we attempted to determine the relative importance of depth and identity, by dissociating disparity-depth and disparity-identity.

We employed an active steering task that dissociates gaze and heading direction. Participants underwent simulated (18 Hz) locomotion through a cloud (100 dots, lifetime 440 ms) at 2 m s−1 for 8 s from an initial trajectory 15 deg (±20%) to the left or to the right of a target tower. Heading was adjusted with a joystick and simulated gaze was continuously computer adjusted so as to keep the tower centred on the projected display (20 deg horizontal). Mean unsigned heading error (gaze-heading angle) over the time course provided a performance measure.

Four types of stimuli were used: (i) veridical disparity depth; (ii) non-veridical disparity (disparity and associated motion-in-depth was randomly assigned to each point in the display); (iii) the left half image of the previous condition to both eyes; (iv) synoptic images (no disparity). No marked advantage was observed when the display contained veridical disparity, and non-veridical disparity produced only a minor impairment in performance in a subset of conditions. We suggest that depth information per se may not be utilised in the perception and control of heading.

Is stereopsis effective in breaking camouflage for moving targets?

It has been suggested that breaking camouflage is one of the major functions of stereopsis (Julesz, 1971). In this study, we found that stereopsis is less effective in breaking camouflage for moving targets than for static ones. Observers were asked to detect a single dot moving on a straight trajectory amidst identical noise dots in random motion. In the three-dimensional (3D) condition, the noise dots filled a cylindrical volume 5.7 cm in height and diameter; the trajectory signal dot moved on an oblique 3D trajectory through the center of the cylinder. In the two-dimensional (2D) control condition, observers viewed one half-image of the 3D cylinder binocularly. Surprisingly, trajectory detection in the 3D condition was only slightly better than in the 2D condition. Stereoscopic tuning for motion detection was also measured with a novel target configuration in which the random motion noise was presented in two depth planes that straddled the fixation plane where the trajectory target was presented. As the disparity between the noise planes and the fixation plane was increased, trajectory detection improved, reaching a peak between 6 and 12 arcmin, and then declining to the 2D level at larger disparities, where the noise became diplopic. Similar tuning measurements were made for detecting a static pattern, a string of five aligned dots presented in the fixation plane between two planes of static noise dots. Adding disparity to the noise planes produced a far greater improvement in static detection than in motion detection, for a comparable range of disparities (1.5-12 arcmin). We speculate that the temporal characteristics of the stereo system are not well suited for responding to moving targets, with the result that stereo does not greatly enhance motion detection in noise.

Fine-scale processing in human binocular stereopsis

Many studies have demonstrated that the human visual system is sensitive to very small differences in relative binocular disparity. It is not known over what monocular regions information is spatially integrated to mediate performance in such tasks. In this study we present psychophysical observations that define the smallest spatial scale involved in disparity processing, and we indicate the nature of the computations performed by the units mediating that disparity discrimination. We show that human observers can identify the sign of disparity of a single target dot when it is embedded in a row of identical dots, with these noise dots presented either in the fixation plane or with a proportion binocularly uncorrelated. In conjunction with the psychophysical data, we explore how a class of simple correlator models of stereopsis must be constrained in order to account for human performance for the same fine-scale tasks. Such models can perform the task only when the correlation is carried out over a very small region of the image, for a very small range of disparities. Our results demonstrate that there is a fine-scale input to the stereo system, mediated by foveal mechanisms that spatially integrate visual signals over a region as small as 4-6 arcmin in diameter.

Holmium:yttrium-aluminum-garnet laser cystolithotripsy of large bladder calculi

OBJECTIVES

Patients with large bladder calculi (4 cm or larger) have traditionally been managed with open cystolithotomy. Endoscopic management with cystolitholapaxy or electrohydraulic lithotripsy risks complications. In an effort to spare patients the morbidity of open cystolithotomy, the results of holmium:yttrium-aluminum-garnet (YAG) laser cystolithotripsy for bladder calculi 4 cm or larger were reviewed.

METHODS

Consecutive patients with bladder calculi of 4 cm or larger were managed with holmium:YAG laser cystolithotripsy. Laser energy was delivered using either the 365-micron end-firing fiber or the 550-micron side-firing fiber.

RESULTS

Fourteen consecutive patients were managed with holmium:YAG cystolithotripsy. All patients were rendered stone free, regardless of stone composition or size. Median anesthesia time was 57 minutes. Twelve of 14 patients were discharged by the first postoperative day. The procedure times normalized for stone size (mean +/- standard deviation) for the end-firing versus the side-firing fibers were 13 +/- 6 min/cm versus 6 +/- 1 min/cm, respectively; P = 0.04.

CONCLUSIONS

Holmium:YAG laser cystolithotripsy of large bladder calculi is effective, technically facile, and safe. The 550-micron side-firing fiber may be better suited for large bladder calculi compared with the 365-micron end-firing fiber. Holmium:YAG cystolithotripsy may obviate open cystolithotomy in selected patients.

Organization and expression of human telomere repeat binding factor genes

The ends of mammalian chromosomes terminate in structures called telomeres. Recently a human telomere repeat binding factor (TRF1) that binds the vertebrate TTAGGG telomeric repeat in situ was isolated by Chong et al. (1). TRF1 regulates telomere length (2), which is often altered in cancer cells. To understand their genetic organization, TRF1 genes were localized to human chromosomes 13cen, 21cen, and Xq13 by analysis of human monochromosomal hybrids, and by fluorescent in situ hybridization. We also confirmed the recent localization of a human TRF1 gene to chromosome 8, and provide evidence that this locus is alternatively spliced. In contrast to the TRF1 genes on chromosomes 8 and X, the chromosomes 13 and 21 TRF1 genes contained a 60 bp deletion in the coding region. The results suggest that two distinct forms of TRF1 are expressed and that the TRF1 gene family includes at least three pseudogenes whose dispersal in the human genome may have occurred via cDNA intermediates.