Sensing glucose concentrations at GHz frequencies with a fully embedded Biomicro-electromechanical system (BioMEMS)

The progressive scaling in semiconductor technology allows for advanced miniaturization of intelligent systems like implantable biosensors for low-molecular weight analytes. A most relevant application would be the monitoring of glucose in diabetic patients, since no commercial solution is available yet for the continuous and drift-free monitoring of blood sugar levels. We report on a biosensor chip that operates via the binding competition of glucose and dextran to concanavalin A. The sensor is prepared as a fully embedded micro-electromechanical system and operates at GHz frequencies. Glucose concentrations derive from the assay viscosity as determined by the deflection of a 50 nm TiN actuator beam excited by quasi-electrostatic attraction. The GHz detection scheme does not rely on the resonant oscillation of the actuator and safely operates in fluidic environments. This property favorably combines with additional characteristics-(i) measurement times of less than a second, (ii) usage of biocompatible TiN for bio-milieu exposed parts, and (iii) small volume of less than 1 mm3-to qualify the sensor chip as key component in a continuous glucose monitor for the interstitial tissue.

What's in a number?

Ten years ago, the first estimates of the existing number of drug targets were made. This month's issue features an article and poster that together summarize current drug targets and associated characteristics, providing a basis to better understand the potential for future therapeutic exploitation.

Case histories, magic bullets and the state of drug discovery

The case histories of five modern drugs are taken as a basis for reflection on the state of drug discovery. Two issues intimately associated with drug research are highlighted: the nature of the intellectual process leading to new discoveries; and the possibility that the principle of selective efficacy, which has guided drug research from its beginnings, might need modification, at least in some areas of pharmacotherapy.

Paul Ehrlich: magister mundi

Paul Ehrlich, a founding father in fields across a wide range of medical sciences, was born 150 years ago. To mark this anniversary, this article gives an overview of his life, highlighting his major scientific contributions and paying tribute to Paul Ehrlich the man.

Levels of parotid and submandibular/sublingual salivary immunoglobulin A in response to experimental gingivitis in humans

Salivary secretory IgA (s-IgA) is considered to act as an important first line of defense mechanism in the oral cavity. It has therefore been suggested that an increased antigenic load would induce an increase in salivary IgA production. This study investigated the pure glandular levels of salivary IgA in parotid and submandibular/sublingual (SM/SL) saliva during plaque accumulation leading to experimental gingivitis. Starting from regular oral hygiene, 14 healthy, nonsmoking men refrained from all oral hygiene measures for 12 days. On days -2, 0, 3, 6, and 12 a plaque index, a bleeding index, and unstimulated and stimulated saliva from the parotid and the SM/SL glands were measured. Salivary IgA was quantified using a sandwich ELISA. All subjects developed gingivitis as measured by a bleeding index. Compared to baseline the salivary flow rate was increased on day 12. Regarding the secretion rate of IgA there was a statistically significant increase in stimulated parotid saliva but not SM/SL saliva compared to baseline after 6 and 12 days without oral hygiene. No significant changes were observed for the concentration of IgA during the trial. Thus, in healthy subjects with regular oral hygiene the development of plaque induced gingivitis is associated with increased salivary gland output and increased total IgA output levels in stimulated parotid saliva but not in SM/SL saliva.

Stategic trends in the drug industry

The promise of genomics in drug discovery, which was eagerly embraced in the mid-1990s, has not yet been fulfilled. However, the influence of modern biology on drug discovery remains viable. The promise of genomics and biology should be put in context with the two central problems of drug discovery: the search for disease-related targets, and the study of drug-protein interactions and protein-protein interactions. The first tier of the biotechnology industry has now become the most productive segment of the drug industry. It combines a high degree of innovative spirit with solid pharmaceutical professionalism. Some biotechnology firms have succeeded in addressing unmet medical needs in technologically appealing ways. In their totality, these changes will deeply alter the nature and appearance of the drug industry.

[Mycotic aneurysms--A retrospective analysis]

12 patients (10 males and 2 females, average age 53 years) were operated upon in our hospital between 1994 and 1999 for mycotic aneurysms. The aneurysms were located in 7 patients in the aorto-iliac segment, 5 patients were treated for peripheral or visceral aneurysms. Two of these patients suffered from multiple aneurysms. When peripheral arteries were affected, a pulsatile tumour was felt. Most of these tumours developed in a relatively short period of time and sometimes a perivascular inflammation occurred. This was not the case when central arteries were attacked. A septic process or an infection, for example salmonella-enteritis, often preceded shortly the development of a mycotic aneurysm. In the case of an aneurysm of the aorto-iliac section we consider an in situ reconstruction with alloplastic material in combination with a perivascular debridement, lavage and omentum majus plastic as the treatment of choice. In peripheral arteries reconstruction should be performed with autologous vessels. Depending on the local findings, a perivascular debridement should also be performed in these cases. The reconstruction always should be combined with a calculated antibiotic therapy. Two of our patients died perioperatively. During follow up, 8 patients showed patent reconstructions and no signs of infection. The urgency of surgery depends on the level of inflammation and the existence of any secondary complications.

Quo vadis, biotech? (Part 2)

Those following the financial markets and the valuation of biotechnology companies recently might find themselves perplexed. Towards the end of 1999, during which the availability of capital for biotech initial public offerings and for private investment rounds seemingly withered, the markets suddenly turned around and gave the biotechnology industry its biggest bonanza ever.

Drug discovery: a historical perspective

Driven by chemistry but increasingly guided by pharmacology and the clinical sciences, drug research has contributed more to the progress of medicine during the past century than any other scientific factor. The advent of molecular biology and, in particular, of genomic sciences is having a deep impact on drug discovery. Recombinant proteins and monoclonal antibodies have greatly enriched our therapeutic armamentarium. Genome sciences, combined with bioinformatic tools, allow us to dissect the genetic basis of multifactorial diseases and to determine the most suitable points of attack for future medicines, thereby increasing the number of treatment options. The dramatic increase in the complexity of drug research is enforcing changes in the institutional basis of this interdisciplinary endeavor. The biotech industry is establishing itself as the discovery arm of the pharmaceutical industry. In bridging the gap between academia and large pharmaceutical companies, the biotech firms have been effective instruments of technology transfer.

The 6 volt battery for implantable cardioverter/defibrillators

The usage of a 6 V lithium manganese dioxide battery results in a significant reduction of capacitor loading time within implantable defibrillators/cardioverters. In order to provide ERI indication a new cathode formulation has been developed. The battery shows no voltage delays, a low self-discharge and fulfilled all requirements to an energy source for an implantable device.

Intent and coincidence in pharmaceutical discovery. The impact of biotechnology

Drug research developed around a purpose: the cure of diseases. This intent to cure, however, offered no clue to the understanding of diseases and to their treatment. Instead such guidance had to come from scientific disciplines which laid the foundations for drug research and offered specific opportunities for the solution of therapeutic problems. In the sequence of their appearance, these scientific disciplines were: chemistry, pharmacology/physiology, microbiology, biochemistry and molecular biology. It can be shown that new therapeutic classes of drugs like muscle relaxants, diuretics, L-dopa, antibiotics, recombinant proteins, monoclonal antibodies and others were generated on the basis of scientific opportunities rather than therapeutic need. All of these drugs were created within the confines of a chemical paradigm of medicine and drug therapy. We are now witnessing the entry of a new informational paradigm into medicine which is most prominently represented by genomic sciences. This paradigm will bring two important changes to the therapy of diseases. First, molecular biology has matured to such a degree that it can now study complex genomes and their functionality in complex organisms such as humans. Therefore, results from these studies no longer have to be translated into the context of medicine: they are already within this context. Secondly, drug therapy which used to be largely symptomatic, will now aim at targets which are closer to the causes of diseases than previously. Therapeutic progress, which used to be indirect, conjectural and coincidental, is about to become more directed, definitive and intentional. At least from the limited and utilitarian perspective of medicine, drug discovery will be more often based on intent rather than coincidence. But industry and, for that matter, society as a whole should not forget that this situation has come about through the evolution of science which was not, and can never be, predictable.

Medicine and genetic engineering: just another method or a new paradigm?

Scientific and technical developments have influenced medicine in a more profound way than any other cultural forces. In our days, molecular biology appears to be the major scientific factor which forms medicine. To those who practise medicine in the clinical environment, this statement may come as a surprise; however, if one looks at therapeutic and diagnostic research, the magnitude of change becomes evident. Most of these changes can still be interpreted in the context of known categories. In the analysis of the human genome, as well as in somatic gene therapy, however, a new principle emerges which will change our understanding of disease in a profound way. The scientific interpretation of disease as well as of diagnosis and therapy was first based on a morphological paradigm, which can be traced back to R. Virchow as well as to his contemporaries and successors. This powerful paradigm was later complemented by a chemical or biochemical paradigm which turned out to be extremely useful: modern diagnostics based on clinical chemistry as well as drug therapy are direct consequences of this influence. The new understanding of disease, diagnosis and treatment, which molecular biology is affording, is centered around the concept of genetic information. Diseases can be interpreted as informational deficits, as manifestations of faulty, inadequate or surplus information. While disease was previously interpreted on the basis of alterations in form and function it can now be seen as a derangement of the flow of information within cells, between cells, and between organs. The consequences for strategies of diagnosis and treatment will be profound.(ABSTRACT TRUNCATED AT 250 WORDS)

Gene technology and the drugs of tomorrow

The progress of pharmaceutical research depends on three factors: on the evolution of medical needs, on societal attitudes, and on scientific and technical feasibility. Among the factors which are 'internal' to science, molecular biology seems to be the most important driving force, at least for the foreseeable future. The influence of molecular biology on pharmaceutical research is occurring in several distinct phases. The first phase was characterized by the use of gene technology as a production instrument for known proteins. In the second phase, gene technology is instrumental in the identification of novel proteins and in the elucidation of their gene structure and physiological function. A great number of proteins which have therapeutic potential will eventually emerge from this phase, with the more important ones like the hematopoietic factors yet to come. During the third phase, gene technology will provide proteins that can serve as pharmacological tools: receptors, ligands, enzymes, cytokines and other proteins provided by gene technology will enable us to open up new fields of pharmacology from which novel drugs, often low molecular weight chemical entities, will emerge. Finally the fourth phase will be characterized by a knowledge of gene structure and regulation extensive enough to develop a pharmacology of gene regulation and to establish somatic gene therapy. New drugs that can be expected to emerge from the interaction of molecular biology and pharmaceutical research within the next ten to twelve years are discussed. It is expected that pharmaceutical research will in the end be transformed into a discipline in which molecular biology and structural chemistry play dominating roles while synthetic chemistry will be reduced to the role of an important tool.

Does active rheumatoid arthritis affect intestinal iron absorption?

One of the causes of anaemia in rheumatoid arthritis is thought to be defective iron absorption. In this study the 59Fe absorption in patients with active rheumatoid arthritis is measured and correlated with the results for bone marrow iron stores (and in some cases with the iron stores in the terminal duodenum), which were assessed simultaneously with semiquantitative methods, and with the serum ferritin concentration. In 11 patients with rheumatoid arthritis and increased bone marrow iron stores, iron absorption was decreased. In five patients it was normal and in three further patients, whose bone marrow iron stores were depleted, iron absorption was maximally increased. According to the results both intestinal malabsorption and defective iron absorption can be excluded as causes.

The experimental and clinical use of immune-modulating drugs in the prophylaxis and treatment of infections

Therapeutic agents capable of stimulating immune responses could be of great value in the prophylaxis and treatment of infectious diseases. Three classes of compounds, each representing a separate approach to the goal of immune stimulation, are discussed with respect to recent experimental and clinical findings. The action of microbial structures and their derivatives can be understood on the basis of "acquired cellular immunity", a phenomenon first described in connection with infections by mycobacteria and other intracellular organisms. In contrast, there is hardly a common denominator for synthetic compounds which are currently used as immune-stimulatory agents. Substances which influence purine metabolism in lymphocytes on the one hand and histamine H2 blockers such as cimetidine on the other hand seem to represent the most promising developments in this field to date. Products of immune cells such as transfer factor and lymphokines form the third and possibly most important group of immune-stimulating agents. Current experimental and clinical trends in this field are briefly described. It is suggested that the delineation of the mechanism of action of lymphokines will open the door to the identification or synthesis of artificial agonists and antagonists as has been the case in the pharmacology of the endocrine and nervous systems.

[Analysis of prognostic factors in plasmacytoma]

For analysis of prognostic factors the clinical course of 109 patients with multiple myeloma was evaluated. Survival curves of immunoglobulin (Ig)G- and IgA-myelomas were identical (Fig. 1) with median survival times of 52 and 42 months, respectively, whereas patients with IgD- and Bence-Jones-myeloma had short survival times (median 3 months). Most important risk factors were anemia, renal insufficiency, and hypercalcemia (Figs. 7 and 8). Median survival time dropped from 52 months (Hb above 100 g/l) to 22 (Hb 85-100 g/l) and 1 month (Hb below 85 g/l). Patients with serum creatinine values below 2 mg/dl lived significantly longer than those with values above. Median survival times were 52 and 1 month, respectively. All seven hypercalcemic patients had a renal insufficiency and were in a very poor condition; their median survival time was 1 month. Analysis of the widely used staging system of Durie and Salmon gave disappointing results. Survival curves of the three A-stages ran close together with median survival times of 58, 51, and 36 months. Only the A-B classification according to renal function (A: creatinine under 2 mg/dl; B: creatinine above 2 mg/dl) proved prognostically relevant.

Immunostimulation. Clinical and experimental perspectives

Three classes of immunostimulating drugs are described, each representing a different approach to the problem of pharmacological immunostimulation. The rationale for the use of microbes or microbial agents as immunostimulators rests on the fact that some micro-organisms, especially those that replicate intracellularly, carry a special potential to activate macrophages. Clinically, the use of these agents in patients with tumors and infections has been disappointing; however, there have been positive exceptions like the responsiveness of melanomas and bladder carcinomas to the injection of BCG. Many of the inconclusive results may be due to insecurities in the dosage of microbial preparations and to a general lack in standardization. Some structures with high efficacy and low toxicity which have recently evolved from this field deserve further investigation. A number of structurally unrelated synthetic compounds was found to influence immune parameters. Levamisole can today be classified as an immunostimulating drug with limited utility in recurring infections and in chronic polyarthritis. Several immunostimulating drugs which have attracted interest contain a purine as the effective component. This is not surprising in view of the fact that many genetically determined immunodeficiencies can be traced to defects of enzymes which play a crucial role in purine biosynthesis. Finally, the potential role of lymphokines as stimulators of the immunosystem is briefly described. Some of these glycoproteins have recently become available for clinical trials. Others will be made available through genetic engineering. The therapeutic utility of these compounds is not yet clear; they will, however, be of great value as probes for the study of immune functions and for the development of immunopharmacology.

The experimental and clinical use of immune-modulating drugs in the prophylaxis and treatment of infections

Therapeutic agents capable of stimulating immune responses could be of great value in the prophylaxis and treatment of infectious diseases. Three classes of compounds, each representing a separate approach to the goal of immune stimulation, are discussed with respect to recent experimental and clinical findings. The action of microbial structures and their derivatives can be understood on the basis of "acquired cellular immunity", a phenomenon first described in connection with infections by mycobacteria and other intracellular organisms. In contrast, there is hardly a common denominator for synthetic compounds which are currently used as immune-stimulatory agents. Substances which influence purine metabolism in lymphocytes on the one hand and histamine H2 blockers such as cimetidine on the other hand seem to represent the most promising developments in this field to date. Products of immune cells such as transfer factor and lymphokines form the third and possibly most important group of immune-stimulating agents. Current experimental and clinical trends in this field are briefly described. It is suggested that the delineation of the mechanism of action of lymphokines will open the door to the identification or synthesis of artificial agonists and antagonists as has been the case in the pharmacology of the endocrine and nervous systems.

In vitro activity of naftifine, a new antifungal agent

Naftifine exhibits an interesting in vitro spectrum of activity against dermatophytes (38 strains; minimal inhibitory concentration [MIC] range 0.1 to 0.2 microgram/ml), aspergilli (6 strains; MIC range, 0.8 to 12.5 microgram/ml), Sporothrix schenckii (2 strains; MICs, 0.8 and 1.5 microgram/ml), and yeasts of the genus Candida (77 strains; MIC range, 1.5 to greater than 100 microgram/ml). Its degree of efficacy is unaffected by the organism density in the test medium, and it is primarily fungicidal against dermatophytes as well as yeasts. Its in vitro efficacy is pH dependent and rises with increasing pH values.

[Clinical trial in couples of effectiveness and side-effects of gold and D-penicillamine in long term treatment of rheumatoid arthritis (author's transl)]

A prospective clinical trial in couples was done to compare effectiveness and toxicity of gold and D-penicillamine (D-Pen.) in treatment of rheumatoid arthritis (r.A.). Respecting defined criteria 70 patients were put to couples according to a random list and were treated with gold or D-Pen. alternatively. Physical and laboratory indices of inflammatory activity were checked every 3 months, X-rays every 12 months. Dropouts (side effects, missing compliance, uneffectiveness) were replaced by the nextcoming fitting patient. Thirty-two of 147 totally recruited patients stopped treatment because of side effects, three because of unsatisfying efficiency. Forty-two patients shuned the necessary controls. The clinical course was better in 16 couples with gold, only in sex couples with D-Pen. Thirteen pairs showed no difference in this respect (p = 0.05). Looking to the laboratory parameters separately D-Pen. tends to be superior (p < 0.05), radiografic deterioration seems to be more seldom with gold (< 0.05). Side effects occur with both drugs in comparable frequency (15/44 with D-Pen., 17/52 with gold), but the complications with D-Pen. are more serious. Altogether this trial shows gold superior to D-Pen. in the long-term treatment of r.A.

Inhibition of mitogen-induced lymphokine production by cyclosporin A

The new antilymphocytic agent Cyclosporin A was found to inhibit the production and/or secretion of migration inhibitory factor (MIF) in human lymphocytes stimulated by Concanavalin A. Preincubation for one hour with the compound, followed by 8 hr restoration period of the cells in absence of the drug, resulted in moderate decrease in MIF synthesis and/or release. Cell viability was not affected. The agent was shown not to interfere with MIF action on the macrophage. We conclude that the molecular mechanism of action of Cyclosporin A is based, at least partially, on a blockade of synthesis and/or secretion of lymphokines from immunocompetent cells.

Differential analysis of selected prompts and neurological variables in motor assessment of moderately mentally retarded children

The purpose of this study was to elevate the specificity of gross-motor assessment strategies presently used with moderately mentally retarded children by measuring voluntary motor performance as a function of level of reflex development, level of orthopedic functioning, and type of prompts used in test instructions. After clinically assessing subjects' levels of reflex and orthopedic functioning, we randomly assigned subjects to multisensory-, physical-, modeling-, and verbal-prompt treatment groups. Multisensory prompts and differential use of selected prompts were effective with younger and older children, respectively. A significant interrelationship was found between subjects' levels of reflex development and voluntary motor performance.

The effect of a protein-bound polysaccharide from Coriolus versicolor on immunological parameters and experimental infections in mice

The influence of PSK, a protein bound polysaccharide from Coriolus versicolor on various immunological parameters was studied, PSK was found to enhance B cell activity as measured by the spleen plaque-forming cell assay in mice, and to stimulate mouse macrophages as determined by an enhancement of carbon clearance and an increase in the phagocytosis of opsonized sheep red blood cells by peritoneal mouse macrophages in vitro. The activation of mouse macrophages by PSK appeared to correlate with the therapeutic effects of the compound. In mice made granulocytopenic with cyclophosphamide and subsequently infected with a variety of garm-negative pathogens or with Candida albicans, PSK prolonged the average survival time of the animals. The compound also led to a drastic increase in the number of animals surviving such experimental infections as compared to untreated controls. Possible mechanisms responsible for these protective effects by PSK are discussed.