The path to a paradigm shift in hemodialysis.

About 1 out of 4 American conventional dialysis patients die in the first year and 3 out of 5 die within 5 years with no favorable trend in sight. Largely ignored in practice is the evidence accumulated over decades that longer, more frequent dialysis can immediately slash this grim result in half or more. Pierratos has called for a paradigm shift--a disruptive change--in dialysis practice from conventional treatment to daily nocturnal dialysis, performed at home, to realize this dramatic improvement. We examine here how such a paradigm shift might be brought about and suggest that changes in 3 perspectives must occur. First, new dialysis guidelines must be recast from the old goal of minimally adequate to a new goal of best possible. Second, the body of dialysis research must be interpreted through the lens of best possible patient survival and well being, and the near-impossibility of demonstrating dialysis survival advantage through randomized clinical trials must be acknowledged. Finally, dialysis modality must be seen as, most importantly, a survival and well-being choice, not merely a "Lifestyle" choice; hence, it must be the nondelegatable responsibility of the physician, not dialysis center personnel, to advise and prescribe. Many old perspectives, which might stand in the way of this sorely needed paradigm shift are also examined. These old perspectives make up a fabric of excuses that has delayed--and, if not discarded, will continue to delay--progress toward a survival and well-being outlook for dialysis patients just as favorable as might be achieved through kidney transplant.

Longer and better lives for patients ... and their centers: a strategy for building a home hemodialysis program.

Physicians should prescribe the dialysis mode most likely to result in the best outcome for the end-stage renal disease patient, not leave it to the patient or dialysis center to choose. That prescription, in order of decreasing desirability, should be for frequent home nocturnal hemodialysis, frequent home short-daily, or least efficacious, 3x in-center or peritoneal dialysis. Patient limitations may require prescribing a less than optimal mode. Physician-patient discussions should focus on expected clinical outcomes and health benefits, not patient convenience or "lifestyle." In order to overcome natural fears, qualified patients should participate in a short in-center frequent dialysis personal clinical trial to experience the benefits. The financial health of dialysis centers will be enhanced by shifting continually inflating labor costs from the center to patients and home caregivers. This shift from 3x in-center to frequent (optimally 6x nocturnal) home dialysis may reasonably be expected to enhance the survival and well-being of both the patient and the center.

Estimates of acute pesticide poisoning in agricultural workers in less developed countries.

The benefits of crop protection products have to be balanced against the risks to farmers and other agricultural workers handling and applying them. The extent of acute pesticide poisoning in these workers, particularly in less developed countries, has often been based on inadequate information. A number of approaches have been taken by researchers to acquire information on pesticide poisoning. These have resulted in worldwide (global) estimates and regional, localised or field assessments. The methods include descriptive epidemiology, cross-sectional and case studies. Attempts to estimate global pesticide poisonings have often been based upon extrapolations and assumptions from chemical-related fatalities in a small number of countries; such estimates do not provide reliable data. Epidemiological studies, relying mainly on hospital and poison centre data, have been biased towards the more severe poisonings, whereas field studies indicate that occupational pesticide poisoning is associated with less severe and minor effects. Many reports do not adequately distinguish between intentional, accidental and occupational pesticide poisoning statistics or are dominated by cases of intentional (suicidal) poisoning which, by their nature, result in severe or fatal results. The majority of reports do not adequately describe whether individual cases are minor, moderate or severe poisonings. In order to assess information on acute pesticide poisoning in agricultural workers in less developed countries and to draw conclusions on the extent and severity of occupational poisoning, the most recent (post-1990) literature was reviewed. Data were also derived from the World Health Organization (WHO), United Nations Environment Programme (UNEP) and the International Labour Office (ILO). The collected information was analysed to assess the extent and severity of occupational acute pesticide poisoning in less developed countries. Occupational acute pesticide poisonings in these countries are a small proportion of overall reported poisoning and are associated with the more minor effects of pesticides. They are a small proportion (<1-4%) of the several million cases of occupational injuries and ill health in agricultural workers worldwide. However, improvements are required for the collection of acute pesticide poisoning data in less developed countries and in the verification of the circumstances of poisonings and their relative severity. There is the need to move away from further attempts to estimate global data and concentrate instead on obtaining reliable data from realistic crop protection activities.

Applications of spatial light modulators in atom optics.

We discuss the application of spatial light modulators (SLMs) to the field of atom optics. We show that SLMs may be used to generate a wide variety of optical potentials that are useful for the guiding and dipole trapping of atoms. This functionality is demonstrated by the production of a number of different light potentials using a single SLM device. These include Mach-Zender interferometer patterns and the generation of a bottle-beam. We also discuss the current limitations in SLM technology with regard to the generation of both static and dynamically deformed potentials and their use in atom optics.

Optical trapping of three-dimensional structures using dynamic holograms.

We demonstrate the use of a spatial light modulator (SLM) to facilitate the trapping of particles in three-dimensional structures through time-sharing. This method allows particles to be held in complex, three-dimensional configurations using cycling of simple holograms. Importantly, we discuss limiting factors inherent in current phase only SLM design for applications in both optical tweezing and atom trapping.

Simultaneous micromanipulation in multiple planes using a self-reconstructing light beam.

Optical tweezers are commonly used for manipulating microscopic particles, with applications in cell manipulation, colloid research, manipulation of micromachines and studies of the properties of light beams. Such tweezers work by the transfer of momentum from a tightly focused laser to the particle, which refracts and scatters the light and distorts the profile of the beam. The forces produced by this process cause the particle to be trapped near the beam focus. Conventional tweezers use gaussian light beams, which cannot trap particles in multiple locations more than a few micrometres apart in the axial direction, because of beam distortion by the particle and subsequent strong divergence from the focal plane. Bessel beams, however, do not diverge and, furthermore, if part of the beam is obstructed or distorted the beam reconstructs itself after a characteristic propagation distance. Here we show how this reconstructive property may be utilized within optical tweezers to trap particles in multiple, spatially separated sample cells with a single beam. Owing to the diffractionless nature of the Bessel beam, secondary trapped particles can reside in a second sample cell far removed ( approximately 3 mm) from the first cell. Such tweezers could be used for the simultaneous study of identically prepared ensembles of colloids and biological matter, and potentially offer enhanced control of 'lab-on-a-chip' and optically driven microstructures.

Bromocriptine treatment of acromegaly following spontaneous conception.

A pregnancy occurring in an untreated woman with active acromegaly is described, together with the clinical and biochemical responses to bromocriptine treatment. It is suggested that bromocriptine treatment need not necessarily be continued throughout such a pregnancy.

Assessment of diagnostic aspiration curettage as an outpatient procedure.

Aspiration curettage proved acceptable to patients and medical staff when incorporated into a busy outpatient practice. The diagnostic reliability of curettings obtained was shown to be 93.5 per cent accurate. In all patients where mucus only is obtained, where symptoms persist or recur, or when aspiration curettage is too distressing, conventional curettage is mandatory.

PIP: An evaluative study of diagnostic aspiration curettage in an outpatient setting is presented. Curettage without analgesia was performed on 208 patients. 93.5% of the diagnoses were confirmed to be accurate. The majority of the diagnostic errors involved the inability to obtain adequate samples. Conventional curettage is mandatory when mucus only is obtained, when symptoms persist, or when aspiration curettage is too distressing. Patients who required diagnostic curettage preferred the aspiration curettage procedure. Aspiration curettage is considered a safe, acceptable procedure, and its use on an outpatient basis will expedite diagnosis.

Dilatation of the parous non-pregnant cervix.

In vitro cervical dilatations were carried out on 33 uteri removed by hysterectomy for conditions not involving the cervix from parous women in their reproductive span of life. A specially designed force measuring dilator was used for all the tests. The analysis of the results involved the application of a thick-walled cylindrical stress determination technique. Using this approach it was possible to calculate quasi-elastic moduli for different degrees of dilatation and obtain theoretical distributions of radial and circumferential stress across the cervical wall. These results indicated a yielding of the cervical tissue at about 9 to 11 mm. dilatation in a significant number of cases.