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Ultrasonography plays critical roles in many aspects of nephrology practice. Applications include the evaluation of the kidneys and urinary tract, guidance for the percutaneous kidney biopsy and temporary hemodialysis access placement, and vascular ultrasound of upper extremities related to the permanent hemodialysis access. The simplicity of technique and the limited spectrum of pathological changes coupled with portability, low cost, and safety make sonography the modality of choice for kidney and vascular imaging. This review summarizes the indications for kidney and vascular ultrasound and describes the most commonly encountered findings. Although many ultrasound findings are nonspecific, their diagnostic use is greatly enhanced by knowledge of the clinical presentation. Therefore, it is essential for nephrologists to possess skills in performing and interpreting ultrasound studies in order to improve the care of patients with kidney diseases.

AbstractSalmonellosis is the second most common cause of bacterial gastroenteritis, yet the yield from routine stool culture is low. Commonly used selective enteric media have poor specificities for salmonella identification, resulting in a high laboratory workload. A special chromogenic medium, ABC agar, is a promising alternative but its cost-effectiveness has not been evaluated in diagnostic laboratories. A collaborative study is therefore undertaken in two district general hospitals laboratories. Routine stool samples (n=866) were subcultured onto ABC agar half plates after selective enrichment in selenite broth. Similarly, 246 and 620 stool samples were subcultured onto desoxycholate lactose sucrose (DCLS) and xylose lactose desoxycholate (XLD) whole agar plates, respectively. Salmonellaspp. were isolated from only 14 (1.6%) of stool samples tested. Specificity was significantly higher for ABC (98%) than DCLS (67%) or XLD (78%) agars. Welcan workload units (ABC 4.8, XLD and DCLS both 7.3) and costs per specimen (ABC £1.26, DCLS £3.81 and XLD £1.83) were similarly lower with ABC agar. The results indicate that ABC chromogenic agar offers improvements in specificity, workload and costs over conventional enteric media for Salmonellaspp. isolation.

Photographic spectrographic calculations of intensity ratios and the corresponding element concentrations are performed faster and more accurately with programmable desk calculators than by graphical methods. These calculations are facilitated by applying a transform to microphotometer transmittance readings to make them linear with respect to intensity. This transform has the form log [{(100 – T)/T} {(a + T)/T}] where a is the transform constant and Tis percent transmittance. A FORTRAN computer program strategy is given for calculating the transform constant from emulsion calibration data and obtaining a linear equation for the emulsion calibration curve. This equation is used to program a desk calculator to convert transmittance readings to intensity ratios corrected for background. A second calculator program computes element concentrations from the intensity ratios.

A procedure for purification of the bungarotoxin-binding fraction of sarcolemma from rabbit skeletal muscle is described. Muscle is homogenized in 0.25M sucrose without high salt extraction and membrane fractions separated initially by differential centrifugation procedures. An ultracentrifugation pellet enriched in cell surface and sarcoplasmic reticulum markers is further fractionated on a dextran gradient (density = 1.0 to 1.09). Two fractions are identified as sarcolemma according to high specific activities for lactoperoxidaseiodination, Na+, K+-ATPase and α-bungarotoxin-binding. No Ca++, Mg++-ATPase activity is found in these fractions. A third fraction, the dextran gradient pellet, is enriched in Ca++, Mg++-ATPase activity and lactoperoxidase iodinatable material and characterized by low bungarotoxin binding. This fraction represents a mixture of sarcoplasmic reticulum and transverse tubules with some sarcolemma contamination.

Summary: Na+-K+-2Cl– cotransport in aortic endothelial cells is activated by cell shrinkage, inhibited by cell swelling, and is responsible for recovery of cell volume. The role of protein phosphorylation in the regulation of cotransport was examined with two inhibitors of protein phosphatases, okadaic acid and calyculin, and a protein kinase inhibitor, K252a. Both phosphatase inhibitors stimulated cotransport in isotonic medium, with calyculin, a more potent inhibitor of protein phosphatase I, being 50-fold more potent. Neither agent stimulated cotransport in hypertonic medium. Stimulation by calyculin was immediate and was complete by 5 min, with no change in cell Na + K content, indicating that the stimulation of cotransport was not secondary to cell shrinkage. The time required for calyculin to activate cotransport was longer in swollen cells than in normal cells, indicating that the phosphorylation step is affected by cell volume. Activation of cotransport when cells in isotonic medium were placed in hypertonic medium was more rapid than the inactivation of cotransport when cells in hypertonic medium were placed in isotonic medium, which is consistent with a shrinkage-activated kinase rather than a shrinkage-inhibited phosphatase. K252a, a nonspecific protein kinase inhibitor, reduced cotransport in both isotonic and hypertonic media. The rate of inactivation was the same in either medium, indicating that dephosphorylation is not regulated by cell volume. These results demonstrate that Na+-K+-2Cl– cotransport is activated by protein phosphorylation and is inactivated by a Type I protein phosphatase. The regulation of cotransport by cell volume is due to changes in the rate of phosphorylation rather than dephosphorylation, suggesting the existence of a volume-sensitive protein kinase. Both the kinase and the phosphatase are constitutively active, perhaps to allow for rapid changes in cotransport activity.

The neoclassical growth model of a capitalistic economy is investigated for stability and optimality properties under the assumption that firms maximize the rate of reduction in their production costs. An optimal trajectory is then shown to be stable relative to exogenous disturbances if it meets certain sufficient conditions placed on its time-varying, linear approximant system in a neighborhood near the trajectory.

Several letters to the editor are presented in response to articles in previous issues including one on the television program "Rowan & Martin's Laugh-In," in the October 11, 1968 issue, one on U.S. presidential candidate George Wallace, in the October 18, 1968 issue, and the essay "The New Black Magic," in the September 27, 1968 issue.

AbstractFusobacterium necrophorumis an obligate anaerobe believed to be a member of the normal flora of the human oropharangeal and urogenital tract. It has been associated with deep-seated infections and was first described in 1936 by Lemierre, a French microbiologist. There is now strong evidence to suggest that it is also a cause of recurrent sore throat and persistent sore throat syndrome (PSTS) without leading to full systemic infection. It is considered to be the second most common cause of sore throat after group A β-haemolytic streptococci. This study was performed over a six-month period (October 2004 to March 2005) at the Eastbourne District General Hospital. All throat swabs received in the laboratory are cultured routinely for haemolytic group A streptococci and pathogenic Corynebacteriaspp. During the study period an extra fastidious anaerobic blood agar plate with neomycin was inoculated, with a 30 µg vancomycin disc placed at the junction of the second and third streaks. This was examined after 48 h for the presence of F. necrophorum. A total of 1157 swabs were processed during the study period: 156 were positive for haemolytic group A streptococci, 57 were positive for F. necrophorum, 47 for group C haemolytic streptococci, nine for group G haemolytic streptococci, and one was positive for C. ulcerans. Patient age ranged from less than a year old to 88. The majority of F. necrophorumisolates were from patients in the 11–25 age group, with an isolation rate of 9.48% (44/464). This age group accounted for 40% (464/1157) of the swabs received during the study period and 77% (44/57) of these were positive for F. necrophorum. Group A haemolytic streptococci showed an overall isolation rate of 13.5%, with peaks of 23% in the 0–10 and 26–35 age ranges. Together, these two organisms were responsible for 18.4% (213/1157) of all throat infections in this study. The results presented here indicate that F. necrophorumis second to group A haemolytic streptococci as a cause of sore throat, especially in the young adult, and introduction of routine culture should be considered.