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Every patent document has two major sections. The first section, called the specification, is primarily a technical document intended to describe the invention in sufficient detail such that a person of ordinary skill in the art can make and use the invention in the best mode contemplated by the inventor. The second section is primarily a legal document and contains the claims. A patent gives the inventor a time-limited monopoly in the invention. The claims provide the legal description of that monopoly. When an inventor asserts a patent against an alleged infringer, the claims determine whether an infringement has occurred. Three types of claims are commonly used for electrical engineering-type inventions. These three types are: apparatus claims, method claims, and means-plus-function claims. Means-plus-function claims are a special type of apparatus claims. In means-plus-function claims, the physical elements of the apparatus are described in the claim by reciting the functional aspects of the elements but not the structural aspects.

The effect of blood-membrane interaction on several biocompatibility parameters has been investigated. Four groups of healthy subjects underwent sham hemodialysis, i.e. the establishment of blood-dialysis membrane contact, but without circulating dialysate, using cellulose-based membranes (regenerated cellulose and cellulose acetate) or synthetic membranes (polysulfone and polyacrilonitrile). Contact between blood and cellulose-based membranes resulted in pronounced complement activation and leukopenia whereas contact between blood and synthetic membranes induced weak complement reaction. The release of granulocytic elastase comparable to that obtained during clinical dialysis seemed to correlate directly with the types of membrane used. The gradual increase in the level of plasma elastase during blood-membrane contact, as opposed to the transient nature of the increase in the levels of complement, suggests that different mechanisms are responsible for these reactions. Nutritional implications of dialysis membrane bioincompatibility are discussed in the light of recently published metabolic data obtained in these subjects.

In the US, software has been patentable subject matter for many years. Nevertheless, it was not uncommon to hear engineers, and even some patent attorneys, assert that software was not patentable. The patentability of mathematical algorithms in the US is not so clear cut, but changes in US patent law have expanded the scope of patentability for mathematical algorithms. Many types of mathematical algorithms that were previously not patentable subject matter are now patentable subject matter. The full impact of these changes is yet to be determined, but the trend is clearly in favor of the patentability of mathematical algorithms. In Europe, the expanding scope of patentability for software and mathematical algorithms is lagging the US to some extent. The patentability of software in Europe was somewhat uncertain. However, a decision by the Technical Board of Appeal (TBA) appears to have removed the uncertainty and clearly established that computer software is generally patentable subject matter in the European Patent Office (EPO). The patentability of a mathematical algorithm is still uncertain. Inventors wanting to obtain patent protection for their mathematical algorithms or computer software should not assume that such protection is unavailable or even that they know where the boundary lies. It is a mistake, and it can be a costly mistake, to presuppose that something is unpatentable simply because it is a mathematical algorithm.

Accessible online at: www.karger.com/journals/bpu The minireviews by Stegmayr and Matic and coworkers, explore the relatively new blood-cleansing domain of immunoadsorption. This technology is a logical outgrowth of past technology for nonspecifically removing unwanted disease-causing proteins from the blood such as endotoxin, and the antibodies directed against glomerular basement membrane, and circulating immune complexes. In the beginning there was plasmapheresis, which separated cells from plasma protein in order to permit exchanging the pathological proteins with ‘normal’ substitutes such as albumin or physiologic saline. As noted in the reviews, biomedical engineering has enhanced both the specificity of this technology as well as the ease of the methods by which it is applied. The latter was accomplished by utilizing the uniqueness of the interaction between a pathological antibody and its corresponding antigen linked to beads in a column or tethered to the walls of a hollow fiber device. While this is a magnificent step forward and will likely enhance the success of life-saving therapies such as xenotransplantation by selectively removing anti-Gal alpha 1-3 Gal antibody (the cause of xenograft hyperacute rejection), there remains a lingering concern about other applications that are less well controlled temporally than placing a xenograft. The problem with septicemia as discussed by Stegmayr below exemplifies this concern. In this clinical setting, by the time clinical awareness of the need for endotoxin removal is manifest and endotoxin appears in significant concentrations in the blood, the triggering of inflamatory mediators is well underway and the specific removal of endotoxin as treatment is ‘too little too late’. By then, one is obliged to consider removing an entire spectrum of reaction products, a considerably more daunting task. The nonmedical analogy of the formula for making perfect toast comes to mind; namely, removal of the toast from the toaster 25 seconds before you see smoke. As is usual with novel medical technology, the capability to accomplish a biomedical task runs well in advance of our understanding of how best to utilize it. And also, as is usual, the new technology provides an elegant study tool to explore the pathophysiology of the offending condition for which it was designed. This field of selective toxin removal is currently under lively investigation and should be watched for contributions to our basic understanding of the major clinical abnormalities begetting kidney failure.

Four patients who received renal homografts were studied during the first 24 hours after operation to determine the mechanisms of the post-transplantation diuresis. The marked diuresis was associated with decreased tubular reabsorption of sodium and glucose. Fractional excretion of filtered sodium reached values as high as 0.12 to 0.21, and fractional excretion of glucose achieved values as high as 0.10 at normal plasma glucose levels. The marked natriuresis and glycosuria subsided or improved spontaneously despite meticulous replacement of all renal and extrarenal fluid and electrolyte losses. In two subjects who excreted a hypotonic urine, free water excretion during the natriuresis rose to values as high as 12 to 20 percent of the glomerular filtration rate. Excreted potassium exceeded filtered potassium in two subjects. The data indicate that the early post-transplantation diuresis is due primarily to intrinsic defects in the proximal tubular transport systems for sodium and glucose whereas t...

This study is concerned with the detectionof overt and latent viruses in explant cultures of renal biopsies from 72 patients with various forms of renal disease. Of the 77 biopsies, 52 grew in culture

In 12 uremic patients, simultaneous records of the ballistocardiogram and the carotid pulse derivative were taken before and after 36 dialyses. The ECG was also taken in many cases. In the great major