The current and future role of the Internet in patient education

The Internet technology known as the World Wide Web is rapidly emerging as the most powerful medium of mass communication this century and it can be harnessed to dispense global, cost-effective, high-quality, multimedia patient education material. This paper reviews how the Internet has progressed from delivering simple static, text-based material to sophisticated interactive Web sites based on CGI Technology. Interactive Web sites can be used to deliver health assessment questionnaires and Web-based decision-support systems can give patients advice on the emergency management of acute medical problems. The advantages and drawbacks of this new technology, including information regulation and quality are discussed. The role of the Hospital Intranet as a patient education resource is described. The paper concludes by illustrating how patients can appreciate the 3-D structure of bones and organs using virtual reality in a VRML Web environment.     

Ambulatory urodynamics: extramural testing of the lower and upper urinary tract by Holter monitoring of cystometrogram, uroflowmetry, and renal pelvic pressures

This article elucidates the clinical applicability and state of the art of ambulatory urodynamics. Ambulatory urodynamics have evolved into practical investigations like EAC, HFM, and EAC combined with renal pelvimetry. EAC has been shown to be the method of preference if detrusor overactivity is involved. Conventional filling cystometry has proved to be an unreliable way to exclude detrusor instability. De novo instability after suspension surgery often indicates that an existing detrusor overactivity was not identified preoperatively. EAC including flowmetry has shown considerable variance in obstructive and contractility parameters in males with LUTS indicative for BPH. This raises doubt whether the clinical flow analysis is the suitable "gold standard" as advocated by the ICS. For a real break through of EAC, less complex automatic analysis is necessary. HFM is a newer method within the range of ambulatory urodynamic tests. It has not yet been completely evaluated. But, because the technique is analogous to the office flowmetry, noninvasive and very well accepted by the patients, it is expected to be widely used. This expectation is strengthened by the fact that HFM seems to show individual therapeutic efficacy of drugs, such as alpha-blockers. As a research tool to evaluate efficacy, it is far more powerful than conventional methods because of the reduction of within-patient standard deviation to about 10%. Finally, EAC combined with pelvimetry offers a promising method for the clinical evaluation of a combined dysfunction of upper and lower urinary tract.     

Evaluation of different disinfection calculation methods using CFD

Computational Fluid Dynamics combined with a particle tracking technique provides valuable information concerning residence times and contact times in chemical reactors. In drinking water treatment, for example an accurate estimation of the disinfection is important to predict the microbial safety. Ozone contactors are widely used for disinfection, but the complex geometry of the system causes suboptimal hydraulics and requires optimizations of the flow. This results in a lower ozone dosage, which may reduce the formation of unwanted disinfection-by-products and the consumption of energy. To that end disinfection needs to be calculated precisely, accounting for the complex hydraulics. Several calculation methods estimating the disinfection performance of ozone contactors were evaluated using Computational Fluid Dynamics. For an accurate disinfection prediction, the full distribution of ozone exposures (CT values) is needed, only a mean CT value or residence time distribution provides insufficient information for an accurate disinfection prediction. Adjustments to the geometry of the ozone contactor that reduce the short-circuit flows resulted in an increase in disinfection capacity, whereas the mean CT value remained the same. A sensitivity analysis with respect to the kinetics was conducted. The gain in disinfection capacity obtained by optimizing the hydraulics was significant for typical values used in practice.     

Non-linear diode ladder network

The analysis and synthesis are presented of a non-linear ladder network with diodes incorporated in the series branches. An explicit form of solution is proposed and then applied to the synthesis of piecewise-linear characteristics. An illustrative example is given.     

Skeletal resistance to the calcemic action of parathyroid hormone in uremia: role of 1,25 (OH)2 D3

Studies were carried out to investigate the role of 1,25(OH)2D3 in the skeletal resistance to the calcemic action of parathyroid hormone. The change in serum calcium after the intravenous infusion of 2 U of parathyroid extract (PTE)/kg body wt/hr for eight hours was evaluated in thyroparathyroidectomized (T-PTX) dogs before, and one, two and three days after, induction of uremia by bilateral ureteral ligation (11 dogs) or by bilateral nephrectomy (8 dogs). In another six nephrectomized and T-PTX dogs, 0.68 ug of 1, 25 (OH)2D3/day was given on the day of nephrectomy and for two days thereafter. Serum creatinine in each day of the study was not different among the three groups. The study also included the evaluation of the effect of sham operation (five dogs) and the administration of 1,25 (OH)2D3 to dogs with normal renal function (four dogs) on the calcemic response to PTE, as well as the reproducibility of such a response in the same animal. The results showed that 1) the calcemic response to PTE was markedly impaired after one day of bilateral ureteral ligation or nephrectomy, but the impairment was more severe after nephrectomy; 2) the calcemic response to PTE after two or three days of bilateral ureteral ligation was similar to that seen at one day after nephrectomy; 3) 1, 25 (OH)2D3 partially restored the calcemic response to PTE in the nephrectomized animals to levels similar to those seen after one day of bilateral ureteral ligation; 4) sham operation did not affect the response to PTE, and repeated infusion of PTE produced similar changes in the concentrations of serum calcium. The data indicate that (a) a deficiency of 1,25 (OH)2D3 is at least partly responsible for the skeletal resistance to the calcemic action of PTH in uremia; (b) uremia, per se, may also contribute to this phenomenon; and (c) the kidney after one day of complete bilateral ureteral ligation may still produce 1,25 (OH)2D3, but this ability is compromised after two days of ureteral obstruction.     

Screening and confirmatory methods for determining lincomycin residues in animal tissues

Methods for screening and for confirming residues of lincomycin in animal tissues, both sensitive to 0.1 ppm, are described. In the screening technique, residues are extracted, cleaned up by solvent partition, and detected by microbiological plate assay. In the confirmatory technique, residues are cleaned up on an unfunctionalized macroreticular-type resin column, concentrated, chromatographed on thin layer plates, and detected by bioautography. This system was effective in identifying lincomycin in the presence of 20 other antibiotics and chemicals used in the animal health industry.     

Antipyrine: radioimmunoassay in plasma and saliva following administration of a high dose and a low dose

The body's equilibrium is possible thanks to the integration of skeletal structure, vertebrae, ligaments and muscles to form one functional unity. The forces which determine posture are composed of two complementary systems, the ligamentary and the muscular systems, which together determine a dynamic act of balance. The ligaments operate mainly against the visco-hydraulic pressure of the nucleus pulposus and bind the vertebral bodies together, whereas the muscles exhibit an antigravity function and support spinal stability. A mathematical model based on a mixed theory of directed and oriented curves is proposed. Through this model it is possible to develop an exact theory governing the deformation of the ligamentous spine. This theory should be universal in the sense that it can be used to supply the spine in any of its environments.