Exaggerated primary endoscope deflection: initial clinical experience with prototype flexible ureteroscopes.

OBJECTIVE: To increase the clinical usefulness of the actively deflectable flexible ureteroscope by making sequential changes in design and then using these prototypes clinically; and to develop a clinical series using the optimum prototype and contrast it with an extensive database of patients treated with the traditional flexible ureteroscope. METHODS: A series of prototypic flexible ureteroscopes was developed and used clinically. The active deflection of the prototype ureteroscope was evaluated with and with no accessories in the working channel, and compared with a standard 7.5 F ureteroscope. Clinical data were then accrued and compared with a previously published database. RESULTS: The progression of prototypes led to a final version which incorporated > 300 degrees primary active deflection, shaft miniaturization (8.4 F) and an increase in endoscope shaft stiffness. The prototype flexible ureteroscope had significantly greater active deflection than the standard ureteroscope, especially when working channel accessories were used. In all, 115 endoscopic procedures were carried out, the indications for which included endoscopic lithotripsy for distal calculi (51), treatment of upper tract urothelial carcinoma (27), diagnostic endoscopy (26) and retrograde endopyelotomy (three). No guidewire was required to place the flexible ureteroscope into the upper urinary tract in 27% of patients. Active intramural dilatation for access was only required in 3% of the procedures. All lower pole calyces were accessed with this instrument. CONCLUSIONS: Adding exaggerated deflection is a timely advance in flexible ureteropyeloscopy. This and the other changes in design facilitated complex retrograde endoscopic procedures and increased the therapeutic potential of the instrument.

Glyoxalase I phenotype as a potential risk factor for prostate carcinoma.

OBJECTIVES: To elicit a possible link between glyoxalase I (Gly-I), a detoxifying enzyme, and the incidence of prostate cancer (PCa), we investigated Gly-I phenotypic expression in the prostatic tissue and red blood cells (RBCs) from patients with PCa. METHODS: Eighty-seven clinical specimens, including 42 PCa tissue samples, 20 RBC samples, and 25 matched pair (prostate and RBC) samples from patients at prostatectomy were examined. The Gly-I phenotypes in these specimens were assessed by nondenaturing starch-polyacrylamide gel electrophoresis. RESULTS: Of the 87 patients, 63 (72.4%) were white, 15 (17.2%) were black, and 9 (10.4%) were another ethnicity (eg, Hispanic, Asian, Indian). Three Gly-I phenotypes were detected in these specimens as fast, intermediate, and slow-moving bands on the gel. The fast phenotype was the most common form found in the white (34 [54%] of 63) and black (8 [53.3%] of 15) patients, but the third ethnic group was too small for proper analysis. To validate this finding, the data from the white patients were compared with the Gly-I phenotypic frequencies in U.S. populations. The data analysis confirmed that a higher incidence (54%) of the fast type in our white patients was statistically significant (P <0.0001) compared with its phenotypic frequency of 30.6% in the general U.S. white population. CONCLUSIONS: The significantly high frequency (P <0.0001) of the fast Gly-I phenotype was detected among patients with PCa, suggesting it is a potential risk factor for PCa. Whether its increased incidence in whites reflects the lack of sample numbers for other ethnic groups needs additional investigation.

Malignant priapism associated with metastatic urethral carcinoma.

We present a 40-year-old man with malignant priapism secondary to urethral squamous cell carcinoma. Magnetic resonance imaging revealed the tumor originating from the bulbous urethra, extending into the penile urethra and corpora spongiosa and cavernosa. A penile biopsy confirmed poorly differentiated squamous cell carcinoma of the urethra. Despite administration of systemic chemotherapy, the prognosis of the patient has worsened due to the extensive metastatic disease.

Determinants of power-frequency magnetic fields in residences located away from overhead power lines.

The Wertheimer-Leeper wire code, originally developed as a surrogate for magnetic-field exposure, has been associated with childhood leukemia in several epidemiologic investigations. However, these and other studies indicate that most between-residence variability in measured magnetic fields remains unexplained by wire codes. To better understand this remaining variability, engineering and demographic data were examined for 333 underground (UG) and very-low current configuration (VLCC) single-family or duplex residences, selected from a database of nearly 1000 residences specifically because their magnetic fields are most likely affected negligibly by overhead power lines. Using linear regression techniques, four factors predictive of the log-transformed residential field were identified: the square-root of the 24-h average net service drop current (this current is equivalent to the current in the grounding system), the log of the number of service drops on the same secondary serving the residence, residence age (four categories), and area type (rural, suburban, or urban). Complete data on ground current and service drops, the two factors with the strongest individual relationships to measured fields, were available for only half of the residences in the sample. However, these data were determined to be "missing at random" according to established statistical criteria. The full-sample or "composite" models thus relied on a method similar to regression imputation, accounting for missing data with binary dummy variables. When applied to the samples from which they were derived, these models accounted for 25% of the variance of the log-spot-measured magnetic field values in the full sample, while models that considered only those residences with complete data (n = 167) explained about 35%. The model validated well against a sample of 201 ordinary low current configuration (OLCC) homes selected from the same database.

Nursing care of patients with implanted pumps.

The implantable pump systems are totally implantable drug delivery systems designed for long-term infusion therapy. These systems have made it possible to maintain the regional delivery of cytotoxic agents and analgesics in a relatively safe and convenient manner for the patient. Regular maintenance is required. The nurse plays a key role in maintaining implantable pump systems, and he or she must have a thorough understanding of the systems and their various applications. Although these systems are complex, the discomfort and restrictions imposed on the patient by their use are minimal. The required maintenance is infrequent and simple enough to allow for greater mobility and freedom from hospitalization for the patient.

Reframing: a strategy to improve care of manipulative patients.

The use of reframing as a means of increasing nurses' choices in their behavioral responses to manipulative patients and an example of how the process might be used to influence nurses' perceptions are discussed. Perceptions influence nurses' behavioral responses. As individuals, nurses become accustomed to approaching new situations with familiar behaviors, and they lose sight of alternative responses. Choices will expand through the process of reframing, an intervention commonly utilized in therapy situations and a method for challenging the attitudes, values, and responses of a person. Simply defined, reframing is changing a person's interpretation of a given situation and therefore changing his or her behavioral response to it. Expanding nurses' choices is a step toward providing improved patient care.

Zinc-induced hemolytic anemia caused by ingestion of pennies by a pup.

A 4-month-old Pomeranian pup was examined because of anorexia, salivation, and persistent vomiting. Initial laboratory testing revealed marked hemolytic anemia with spherocytosis. Survey abdominal radiography revealed 4 metal objects which, when removed by gastrotomy, were identified as pennies. Of 4 pennies, 3 were minted since 1983 and were heavily pitted over the surface and rim. Partially digested pennies were composed of a copper-plated high zinc concentration alloy. Further laboratory testing indicated a marked increase in serum zinc concentration in the pup (28.8 mg/L), confirming metal toxicosis. Serum zinc concentrations decreased during recovery.

Repeatability of four clinical methods for assessment of lumbar spinal motion.

Spinal motion usually is recorded from subjective observation of the fully flexed trunk using a goniometer or the distance from the fingertips to the floor. To quantify functional improvement in the low-back pain patient, the repeatability of four clinical techniques was studied: the common fingertip-to-floor distance; the modified Schober; the two-inclinometer method, and a photometric technique. Ten normal subjects (five men, five women), ages 24 to 34 years old, were examined in full flexion, full extension, and the erect position, both standing and sitting. Repeatability was poor for the fingertip-to-floor method in all postures and for the two-inclinometer method in full flexion. Although other methods for various postures had good repeatability, the modified Schober method of determining lumbar spinal motion was the most repeatable and is recommended for a routine, noninvasive, clinical evaluation of lumbar spinal motion.

Trunk extensor EMG-torque relationship.

The integrated surface electromyogram (IEMG) of the lumbar erectores spinae and the torque generated were simultaneously recorded from 27 healthy subjects in the standing posture while they pulled isometrically against resistance provided by a harness around the shoulders. The IEMG-torque ratio (efficiency of electrical activity, or EEA) was used to characterize each subject. Individual recordings showed evidence of nonlinearity of the IEMG-torque relationship in that a statistically better fit to experimental recordings was obtained by using two straight lines with a breakpoint between them. However, with repeated testing, the gradients of these two lines were more variable than the slope of the single straight line fitted to the entire recording. The slope of the best fit line (EEA) was less for recordings made during torque decrease than for increasing-torque recordings. This also showed as a "hysteresis" pattern in the recordings. The coefficient of variability (within subjects) of the EEA was greater in day-to-day testing (24%) than with repeated pulls at the same testing session (14%). This was similar to variability of the maximum generated torque. About 25% of the variability between subjects was found to be due to anthropometric differences. The residual variability of the relationship would limit the accuracy of IEMG as a measure of muscular effort under changing torque conditions. However, the EEA may be useful for characterizing muscle performance, especially when maximum effort cannot be achieved.

Gene expression in Drosophila: post-translational modification of aldehyde oxidase and xanthine dehydrogenase.

Maroon-like homozygotes are completely deficient for xanthine dehydrogenase (XDH) and aldehyde oxidase (AO), however, ma-l is not a structural locus for either enzyme. Quantitative immunoelectrophoresis of ma-l and wild type extracts suggests that the ma-l function must be post-translational. To determine whether the ma-l function involves some direct physical changes in XDH and/or AO the enzymes were characterized with respect to temperature sensitivity and behavior in gel sieving electrophoresis. Since the XDH and AO from complementary ma-l heterozygotes is more thermolabile and different in shape from wild type XDH and AO, we conclude that ma-l is involved in a post-translational modification of these enzymes.

Structural flexibility of isozyme variants: genetic variants in Drosophila disguised by cofactor and subunit binding.

Wild populations of Drosophila mojavensis exhibit considerable conformational variation in the NAD+-free form of alcohol dehydrogenase (alcohol:NAD+ oxidoreductase; EC 1.1.1.1). The variation appears genetic, as it does not occur within an inbred strain. The NAD+-bound form of alcohol dehydrogenase, present in the same individuals, does not exhibit the variation, suggesting that the binding of NAD+ acts to stabilize conformation. Such cofactor binding to enzymes may thus conceal considerable variation. A similar effect is suggested for binding of esterase subunits.

Evaluation of the Stepwise Mutation Model of Electrophoretic Mobility: Comparison of the Gel Sieving Behavior of Alleles at the Esterase-5 Locus of DROSOPHILA PSEUDOOBSCURA.

Seven alleles at the esterase-5 locus of Drosophila pseudoobscura appear approximately uniformly spaced on 5% acrylamide gels. Such stepwise "ladders" in mobility have been used to argue for the charge-state model of electrophoretic mobility. To evaluate this interpretation, flies of the seven strains were examined in replicate electrophoresis on polyacrylamide gels of differing pore size, permitting estimation of the relative contributions of charge and of size/conformation to electrophoretic mobility. Six of the seven strains examined proved to be heterogeneous, containing multiple variants that migrate to similar positions on 5% acrylamide gels. In the one strain genetically analyzed to date, the hidden variants segregate in crosses. A total of fourteen variants are detected by this gel sieving analysis, many of them involving apparent conformational differences. Thus, protein properties in addition to net charge appear to play an important role in determining the degree of mobility difference between alleles. Examining estimates of free mobility, uniform charge differences are the rule within conformational classes. However, the superposition of conformational heterogeneity renders interpretation of mobility spacing solely in terms of such charge differences inappropriate.

Characterization of electrophoretically cryptic variation in the alpine butterfly Colias meadii.

Enzyme polymorphism was characterized among the proteins of 14 loci of Coliae meadii by replicate electrophoresis in polyacrylamide gels of differing pore size. The results reveal a large number of variants, with a very skewed frequency distribution. A large fraction of the variants cannot be differentiated by electrophoresis in 5--7% acrylamide gels. This gel sieving approach permits an estimate of the relative contributions of charge and of conformation to electrophoretic mobility. Many of the variant proteins do not differ in charge. Most variants exhibit different degrees of interaction with the gel and presumably differ in conformation.

Polymorphism and predictability at the alpha-glycerophosphate dehydrogenase locus in Colias butterflies: gradients in allele frequency within single populations.

Heterozygosity at the alpha-glycerophosphate dehydrogenase locus of five species of Colias butterflies is widespread in montane populations; alpine and lowland populations are not heterozygous. Within a single demographically characterized population of C. meadii where the population extends from alpine down into montane habitats, a marked cline in allele frequency is seen. Such within-population clines suggest the involvement of strong selection across the marked ecological interface. Thermal factors are the most likely causative agents, but associative overdominance is not excluded.