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PubMed2004

Renal artery surgery in the era of endovascular intervention.

BACKGROUND: In the last decade the therapeutic concept of renovascular disease has changed. The numbers of primary surgical revascularisations have fallen substantially due to the invention of percutaneous transluminal angioplasty (PTA). PATIENTS AND METHODS: Retrospective data analysis. From September 1992 to December 2001, 42 patients were operated on 49 renal arteries at our institution. During the same period, 166 PTA of renal arteries alone and 92 PTA with stent were performed. Twenty-five patients and 27 renal arteries were operated encompassing an aortic reconstruction due to atherosclerosis (aortic occlusion 14, aortic aneurysm 11). The median age at operation was 61 years (range 47 years to 76 years). Four patients were operated on because of renal artery aneurysms with a diameter of more than 2.5 cm. The median age of these patients was 68.5 years (range 60 years to 77 years). Seven patients presented with atherosclerotic changes of the renal artery without aorto-iliac involvement. Their median age was 62.8 years at operation (range 39 years to 77 years). Of these, one suffered from rupture of the renal artery during PTA and needed emergency surgery: Six patients and 11 renal arteries with FMD were surgically reconstructed. RESULTS: The primary patency rate of all reconstructed renal arteries of surviving patients after 5 years was 92%, the secondary patency rate after 5 years was 98%. Two patients died perioperatively (4.7%). One patient had presented with a symptomatic thoraco-abdominal aneurysm and died ultimately because of a stroke. The second patient had an infrarenal AAA and died after a myocardial infarction. Twenty (47.7%) of all surgically treated patients had had at least one PTA preoperatively. CONCLUSION: During the last decade, primary surgical renal artery reconstruction was performed in about half of the cases. The decrease of primary open surgery of the renal arteries was most striking in patients with aorto-iliac occlusive disease. From 1996 on no patient of this group underwent open surgery without having had prior PTA of the renal arteries.

Adult↗
PubMed1999

Finland's first anaesthesia revealed by newspapers.

BACKGROUND: According to the literature on the history of anaesthesia, Finland's first anaesthesia was given on March 8, 1847 for a ligature of an aneurysm of the subclavian artery. It has, however, not been possible to verify the date with certainty. We therefore wanted to find out whether newspapers might give additional information and how this exceptionally important medical invention had been received by the Finnish newspapers. METHODS: Microfilms of the 10 newspapers which appeared in Finland in 1847 were studied at the Helsinki University library. RESULTS: The first report which made reference to English newspapers was published on February 10 by "Borgå Tidning". On March 6, "Helsingfors Tidningar" wrote that two anaesthesias had already been given in Helsinki; the first of them for a difficult varicose veins operation and the second for an exarticulation of a shoulder. But there was no information regarding the dates of the operations. Fortunately, both operations had been recorded in the patient diary of the clinic, although without any information about the anaesthesia. According to the diary, Johan August Orn was operated for varicose veins on February 16 and Anders Gustaf Henrikson had his right arm exarticulated on March 3. Both patients recovered. In total, only six pieces of news on anaesthesia were found. CONCLUSIONS: Finland's first anaesthesia was given on February 16, 1847, which is three weeks earlier than had been previously assumed.

Amputation, Surgical↗
PubMed2000

A catheter technique in ophthalmic regional anaesthesia. Cadaver experiments.

BACKGROUND: Regional anaesthesia for ophthalmic surgery is generally accomplished by peri- or retrobulbar techniques. Depending on the duration of ophthalmic surgery, reblock might become necessary. Our goal was to invent a catheter technique for ophthalmic regional anaesthesia that enables the user to administer local anaesthetics intraoperatively into the peri- or retrobulbar space continuously. METHODS: Twenty-five adult cadaver orbits of normal size and anatomy were used for the experiments. A flexible catheter was introduced transcutaneously or transconjunctivally into the extra- or intraconal space. Methylene blue solution was injected through the catheter. RESULTS: Using the same transcutaneous retro- and peribulbar technique, it was possible to introduce flexible catheters into a proper position of the cadaver orbits. The injected dye was found intra- or extraconally. CONCLUSION: Examining the spread of the dye in the orbit, we concluded that it is possible to provide ophthalmic anaesthesia for surgery through an indwelling catheter. We proved that continuous or intermittent administration of a local anaesthetic agent into the extra- or inraconal space can be achieved and this technique may allow us to maintain anaesthesia as long as it is necessary.

Anesthesia, Conduction↗
PubMed2000

The accuracy of the Vivacare true pressure-sensitive periodontal probe system in terms of probing force.

BACKGROUND: The Hunter TPS Vivacare periodontal probe was invented to perform consistent, accurate and reliable periodontal examinations "with controlled pressures". AIMS: The aims of the present investigation are 3: (1) what is the accuracy of the probing force when various probe heads are used in a correct operation position; (2) what is the effect of over- and under-reading of the operation position on the probing force; (3) what is the accuracy of the probing force when different probe handles are used. The Hunter TPS probe consists of a tip connected to a special spring mechanism, which controls the pressure extended to the probe tip. According to the manufacturer, the force indicator lines coincide at approximately 20 g force. METHOD: The test apparatus consisted of an electronic balance, and an electronic caliper. 12 TPS probes tips and 3 handles were selected to test whether there were differences in force between probes. Each probe tip was adapted to the same handle and tested 10 times. In a 2nd test, the TPS handles and over-, accurate-, and under-readings were analyzed as to how they affect the probing force. The 12 TPS probe tips were connected to each of the 3 handles and tested 10x for each of 3 handles and levels. RESULTS: The range in force between TPS probe tips was 8.4 g (p<0.001). For the handles as well as for each of the readings of the operating positions, the differences were small and non-significant. However, between over- and under-readings, there were statistical significant differences. CONCLUSION: The conclusion is that the variation in force between probe tips is high and always above the manufacturer's "approximately" 20 g. As long as the same handle and the same probe tip are used together, and the examiner is reading the markings correct, the TPS probe is adequate.

Electronics, Medical↗
PubMed2002

The road ended up at stem cells.

For me the search for hematopoietic stem cells (HSC) actually started with the discovery by Till, McCulloch, and colleagues (1-3) that bone marrow contained single cells that could give rise to myeloerythroid colonies in the spleen, and sometimes these colonies contained cells that made more spleen colonies as well as radioprotected and reconstituted lethally irradiated mice (3). But in retrospect, it should have started with the remarkable observation of Ray Owen in 1945 that bovine fraternal twins sharing a single placenta and blood circulation retained production of blood cells genetically defined to be from both throughout their life (4). It could be argued that this was the experiment that began both modern experimental hematology as well as modern cellular immunology. The Till, McCulloch, Wu, Becker, and Simonovitch experiments were elegant demonstrations that single, genetically marked cells existed (random DNA breaks and translocations induced by sublethal irradiation of the donor bone marrow) that could both self-renew and differentiate (2, 5). But these experiments did not put the pure cells in the hands of scientists, and so most of their functions for the next 25 years were implied rather than directly analyzed. Just as genetics is the complement to biochemistry (when one considers genes and gene products), cell marking is the complement to cell purification in the fields of developmental and cellular biology. The first attempts at such cellular purification came from the 'school' of Till & McCulloch (6, 7), and independently the school of Van Bekkum in the Netherlands (8). But what was lacking in those experiments and at that time were both a comprehensive approach that would take into account the clonal activity of stem cells in both self-renewal and differentiation to all blood cell outcomes, and the tools with which one could separate what turned out to be an extremely rare population in the bone marrow. And, it wasn't known until much later that most day 8-10 spleen colonies were the progeny of progenitors, not stem cells (9). Two inventions facilitated the technology of purification of HSC: the advent of monoclonal antibody technology by Kohler & Milstein (10), and the development of the multiparameter fluorescence activated cell sorter by the Herzenberg group (11). My laboratory had established assays for the clonal precursors of T cells and B cells, and we had been using the Till-McCulloch spleen colony clonal assays since the mid-1960s. In the late 1970s and early 1980s we began in earnest the search for mouse early hematopoietic progenitors, including HSCs (12-16). The purification of HSCs proved to be much like the purification of an enzyme, or a cell surface receptor, or a gene. Successive enrichments finally led to the isolation of a population, which could no longer be subdivided and which contained precursors that read out in all clonal assays as well as in radioprotection of lethally irradiated hosts (17). Our first experiments transplanting single HSC in 1991 and 1992, led to the definitive demonstration that these were indeed HSCs (18-20). But these experiments and the ideas that led to them were developed in the context of immunology and experimental hematology as they were emerging in the 1950s and 60 s. This volume of Immunological Reviews is a rich testimony to the kinds of ideas and experiments that, at least in retrospect, turned out to be critical. Many roads were taken, but only one ended up at stem cells.

Allergy and Immunology↗
PubMed2004

Charting the language of leadership: a methodological investigation of President Bush and the crisis of 9/11.

In many ways, leadership is a phenomenon that is ideally suited for new and inventive research methods. For researchers who seek to reliably study and systematically compare linguistically based elements of the leadership relationship, computerized content analysis has the potential to supplement, extend, and qualify existing leadership theory and practice. Through an examination of President Bush's rhetoric and the media coverage before and after the crisis of 9/11. the authors explore how elements of the President's speeches changed in response to the post-crisis environment. Using this example, the authors illustrate the process of computerized content analysis and many of its strengths and limitations, with the hope of facilitating future leadership research that uses this approach to explore important contextual and symbolic elements of the leadership relationship.

Communication↗
PubMed2005

Was Babbage's Analytical Engine intended to be a mechanical model of the mind?

In the 1830s, Charles Babbage worked on a mechanical computer he dubbed the Analytical Engine. Although some people around Babbage described his invention as though it had authentic mental powers, Babbage refrained from making such claims. He does not, however, seem to have discouraged those he worked with from mooting the idea publicly. This article investigates whether (1) the Analytical Engine was the focus of a covert research program into the mechanism of mentality; (2) Babbage opposed the idea that the Analytical Engine had mental powers but allowed his colleagues to speculate as they saw fit; or (3) Babbage believed such claims to be fanciful, but cleverly used the publicity they engendered to draw public and political attention to his project.

Cognitive Science↗
PubMed1999

Spontaneous confabulators fail to suppress currently irrelevant memory traces.

Human actions require integration of past experiences, ongoing percepts and future concepts. To adapt behavior to reality, the brain must identify mental representations of current relevance. Occasional amnesic subjects act according to invented stories ('spontaneous confabulations'), disregarding present reality. We used repeated runs of a continuous recognition task to measure the ability to distinguish currently relevant from previously encountered but currently irrelevant information. Spontaneous confabulators detected target items as accurately as nonconfabulating amnesics, but increasingly failed to suppress false-positive responses, confusing presentation in previous runs with presentation in the current run. Lesions involved the anterior limbic system: medial orbitofrontal cortex, basal forebrain, amygdala and perirhinal cortex or medial hypothalamus. We suggest that the anterior limbic system represents 'now' in human thinking by suppressing currently irrelevant mental associations.

Amnesia↗
PubMedDate not supplied

Characterization of beta-thalassaemia mutations using direct genomic sequencing of amplified single copy DNA.

Direct sequencing of specific regions of genomic DNA became feasible with the invention of the polymerase chain reaction (PCR) which permits amplification of specific regions of DNA. Recently, human mitochondrial DNA was amplified and directly sequenced. Using a thermostable DNA polymerase of T. aquaticus (Saiki, R.K. et al., manuscript in preparation) in the PCR, we have applied a combination of PCR and direct sequence analysis of the amplified product to a human single-copy gene. We studied the genomic DNA of five patients with beta-thalassaemia whose mutant alleles were uncharacterized, and found two previously undescribed mutations, along with three known alleles. One new allele is a frameshift at codons 106-107 and the other is an A-C transversion at the cap site (+1) of the beta-globin gene. This latter is the first natural mutation observed at the cap site and it occurs in a gene which is poorly expressed.

Base Sequence↗
PubMed2000

Amplifying quantum signals with the single-electron transistor

Transistors have continuously reduced in size and increased in switching speed since their invention in 1947. The exponential pace of transistor evolution has led to a revolution in information acquisition, processing and communication technologies. And reigning over most digital applications is a single device structure--the field-effect transistor (FET). But as device dimensions approach the nanometre scale, quantum effects become increasingly important for device operation, and conceptually new transistor structures may need to be adopted. A notable example of such a structure is the single-electron transistor, or SET. Although it is unlikely that SETs will replace FETs in conventional electronics, they should prove useful in ultra-low-noise analog applications. Moreover, because it is not affected by the same technological limitations as the FET, the SET can approach closely the quantum limit of sensitivity. It might also be a useful read-out device for a solid-state quantum computer.

Journal Article↗
PubMed2001

At the interfaces of epidemiology, genetics and genomics.

You come onto the court prepared for tennis but your partner seems to be ready for rugby. Neither of you is at all sure what it is that your opponent wants to play. The only recourse is to teach each other the rules of your own game and then decide whether you can collectively invent a new sport. Welcome to the dialogue at the intersections of epidemiology with genetics and genomics.

Alleles↗
PubMed2001

The art and design of genetic screens: zebrafish.

Inventive genetic screens in zebrafish are revealing new genetic pathways that control vertebrate development, disease and behaviour. By exploiting the versatility of zebrafish, biological processes that had been previously obscured can be visualized and many of the responsible genes can be isolated. Coupled with gene knockdown and overexpression technologies, and small-molecule-induced phenotypes, genetic screens in zebrafish provide a powerful system by which to dissect vertebrate gene function and gene networks.

Animals↗
PubMed1995

The case for genomic patenting.

Opposition to the patenting of genomic inventions threatens to erode the foundation of intellectual property rights needed to convert innovative research into new drugs, vaccines and diagnostic tests.

Base Sequence↗
PubMed2005

Culinary archaeology: Millet noodles in Late Neolithic China.

Noodles have been a popular staple food in many parts of the world for at least 2,000 years, although it is debatable whether the Chinese, the Italians or the Arabs invented them first. Here we analyse a prehistoric sample of noodles contained in a well preserved, sealed earthenware bowl discovered in the Late Neolithic archaeological site of Lajia in northwestern China. We identify millet as the source of the abundant seed-husk phytoliths and starch grains present in the vessel. This shows that the conversion of ground millet flour into dough that could be repeatedly stretched into long, thin strands for the preparation of boiled noodles was already established in this region 4,000 years ago.

Agriculture↗
PubMed2000

The most elegant immunological experiment of the XIX century.

When we remember that immunology was barely a decade old and knowledge of circulating antibodies only two years old when Ehrlich performed the experiments described, we can appreciate the inventiveness of his experimental designs. With little wasted effort he planned simple and rapid experiments to answer crucial questions about the mechanism of passive transfer of antibody from mother to fetus to suckling young. Most remarkable and difficult were the foster mother experiments, as anyone who has tried these with mice will attest. But they were judged to be critical and thus were pursued with ultimate success. These experiments would not be improved upon for 60 years, when the identification of immunoglobulin classes made differential transplacental and transglandular passage of immunoglobulins an object of interest. To conceive of studying the kinetics of the immune response by measuring changes in antibody concentration in the milk of lactating animals was yet another demonstration of the fertile imagination that had contributed so much to histology and hematology, and would soon contribute equally to experimental oncology and to scientific pharmacology.

Animals↗
PubMed1995

Visualizing life on biomembranes by atomic force microscopy.

Since its invention in 1986, the atomic force microscope (AFM) has become one of the most widely used near-field microscopes. Surfaces of hard samples are imaged routinely with atomic resolution. Soft biological samples, however, are still challenging. In this brief review, the AFM technique is introduced to the experimental biologist. We discuss recent data on imaging molecular structures of biomembranes, and give detailed information on the application of the AFM with two representative examples. One is imaging plasma membrane turnover of transformed renal epithelial cells during migration in vivo, and the other is visualizing macromolecular pore complexes of the nuclear envelope of aldosterone-sensitive kidney cells.

Animals↗
PubMed2002

Ultrafast precessional magnetization reversal by picosecond magnetic field pulse shaping.

Since the invention of the first magnetic memory disk in 1954, much effort has been put into enhancing the speed, bit density and reliability of magnetic memory devices. In the case of magnetic random access memory (MRAM) devices, fast coherent magnetization rotation by precession of the entire memory cell is desired, because reversal by domain-wall motion is much too slow. In principle, the fundamental limit of the switching speed via precession is given by half of the precession period. However, under-critically damped systems exhibit severe ringing and simulations show that, as a consequence, undesired back-switching of magnetic elements of an MRAM can easily be initiated by subsequent write pulses, threatening data integrity. We present a method to reverse the magnetization in under-critically damped systems by coherent rotation of the magnetization while avoiding any ringing. This is achieved by applying specifically shaped magnetic field pulses that match the intrinsic properties of the magnetic elements. We demonstrate, by probing all three magnetization components, that reliable precessional reversal in lithographically structured micrometre-sized elliptical permalloy elements is possible at switching times of about 200 ps, which is ten times faster than the natural damping time constant.

Journal Article↗
PubMed2002

Sub-ångstrom resolution using aberration corrected electron optics.

Following the invention of electron optics during the 1930s, lens aberrations have limited the achievable spatial resolution to about 50 times the wavelength of the imaging electrons. This situation is similar to that faced by Leeuwenhoek in the seventeenth century, whose work to improve the quality of glass lenses led directly to his discovery of the ubiquitous "animalcules" in canal water, the first hints of the cellular basis of life. The electron optical aberration problem was well understood from the start, but more than 60 years elapsed before a practical correction scheme for electron microscopy was demonstrated, and even then the remaining chromatic aberrations still limited the resolution. We report here the implementation of a computer-controlled aberration correction system in a scanning transmission electron microscope, which is less sensitive to chromatic aberration. Using this approach, we achieve an electron probe smaller than 1 A. This performance, about 20 times the electron wavelength at 120 keV energy, allows dynamic imaging of single atoms, clusters of a few atoms, and single atomic layer 'rafts' of atoms coexisting with Au islands on a carbon substrate. This technique should also allow atomic column imaging of semiconductors, for detection of single dopant atoms, using an electron beam with energy below the damage threshold for silicon.

Journal Article↗