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Biomedical subjects

E Hildebrand

Publications and source records attributed to E Hildebrand.

At least 19 recordsLinked to original sources
PubMed2006

[Self-inflicted finger-amputation: insurance fraud or accidental injury?].

A 50-year-old surgeon was working with his electrical circle saw as a do-it-yourselfer. He was alone, nobody witnessed his mishap when he amputated his left index finger. He claimed high financial compensation from two accident insurance companies because of his disability. A long series of medical expertises followed. The juridical procedures took 12 years in total. All higher authorities had to deal with the forensic medical implications. Finally, the high court (Bundesgerichtshof) decided that the complainant would receive no compensation because he gave two very different descriptions. Concerning the reconstruction of the accident, the first version was unlikely from a biomechanical point of view. The decision of the court was solely based on the violation of the obligation to give a clear presentation of the course of events (Obliegenheitsverletzung).

Accidents↗
PubMed2006

Sperm chemotaxis in marine invertebrates--molecules and mechanisms.

Sperm are attracted by chemical substances which are released by the egg. This process is called chemotaxis. Several molecules that are involved in chemotactic signaling of sperm from marine invertebrates are described and a model of the signaling pathway is presented. We discuss the motor response during chemotaxis and propose a model of the navigation strategy of sperm.

Animals↗
PubMed2005

Sperm chemotaxis: a primer.

Sperm become attracted by chemical substances that are released from the outer coating of the egg, a process called chemotaxis. In this paper the cellular pathway and the motor response during chemotaxis of sperm from sea urchin and starfish are briefly outlined.

Animals↗
PubMed1998

[Self-mutilating hand and finger injuries among physicians suspected of insurance fraud].

27 cases of questionable self-mutilation among physicians (concerning finger and hand injuries) were analyzed retrospectively. The evaluation based on files of the insurance companies, reconstructive examinations and experimental investigations. Three typical cases are described in detail, the "victims" were suspected to have committed a special kind of fraud in order to claim financial compensation from their accident-insurance companies; the contract included special invalidity payments for finger injures (so-called "Gliedertaxe"). Many of these physicians had worked in the surgical field: apart from one 38-year-old female all of them were males, aged between 41 and 66 years. The mutilating instruments were often circular saws, sometimes chain saws and a great variety of other tools, for example hatchet, big scissors and other sharp instruments. By means of forensic-medical expertise and criminalistic investigations the insurance companies were able to demonstrate clearly that the amputation was voluntarily self-inflicted. The forensic-medical argumentation concerning intentional self-mutilation included the so-called execution position of the finger, the injury pattern, the investigations of blood stains and ergonometric aspects.

Adult↗
PubMed1998

[Self-mutilation as insurance fraud].

The case of a self-amputation of the left-sided forefinger is presented. It was an isolated smooth amputation near the basic ankle of the finger without any accompanying injury of other fingers. The victim (a physician) claimed financial compensation from his accident-insurance; his contract included special disability taxes for finger injuries. However, the insurance company did not pay but was able to demonstrate--by means of a medico-legal reconstructive expertise--that the amputation was voluntary and self-inflicted. The argumentation concerning self-mutilation is presented (including the so-called execution-position of the finger and ergonometric aspects). Concerning the surgical care, intervention and diagnostic procedures a detailed documentation of the case history and the morphology of the injury pattern are recommended (especially in isolated finger-amputations of the non-working hand.

Aged↗
PubMed1997

[131 cases of exhumation in Hamburg and their significance for legal medicine and medical insurance (1971-1995)].

The results of 131 forensic exhumations performed by the Institute für Legal Medicine in Hamburg from 1971 up to 1995 are presented and analysed. 50 exhumations have been ordered by legal authorities concerning criminalistic aspects. 81 cases have been commissioned by insurance companies. 7 categories of cases have been established which are separately analysed (e.g. suspicion of intoxication, accidental cases, occupational diseases). A synopsis presents the evidence of several pathological findings in regard to the body's lay-days in the grave compared with similar studies. The study gives evidence of the value of specific findings even if the body had been buried one or two years before exhumation. In 65 of 92 cases the suspected cause of death could be confirmed. In 121 cases the cause of death was definitely cleared up by autopsy. 125 exhumations (approximately 95%) have been successful concerning the underlaying question that gave reason for further examinations. Exhumations turned out to be very useful in order to clarify insurance-related medical questions.

Autopsy↗
PubMed1996

Fatal fat embolism in acute hepatic necrosis with associated fatty liver.

We report two cases of generalized nonviolent hepatogenic fat embolism. A 63-year-old woman was sent to the hospital with suspected mushroom poisoning. Shock symptoms occurred quickly and could not be treated effectively; the patient died 24 h after admission. Postmortem examination showed acute yellow dystrophy of the liver with a severe preexisting fatty liver. Any intoxication including Amanita phalloides could be excluded. In all probability, a fulminant viral hepatitis caused liver dystrophy, and the decay of the fatty liver cells led to generalized fat embolism as the cause of death. The second patient, a 46-year-old man, was reported to have suffered from an acute illness while in prison and died after having been transferred to the local hospital. Histological examinations showed an acute liver dystrophy probably caused by fulminant viral hepatitis with fatty degeneration. In this case, the cause of death was also found to be generalized fat embolism.

Acute Disease↗
PubMed1992

Nonrandom structures in the locomotor behavior of Halobacterium: a bifurcation route to chaos?

Halobacteria spontaneously reverse their swimming direction about every 10-15 s. They respond to light stimuli by a transient perturbation of this rhythm. During periodic stimulation the system shows features that are known from nonlinear oscillators. Increasing stimulation frequencies cause the following phenomena: (i) the frequency of reversals follows the stimulation frequency, (ii) transition to a state where a long and a short interval occur alternatingly and further transition to four interval lengths, (iii) appearance of irregular interval sequences, which, in a two-dimensional plot of successive intervals, reveal clearly discernible structures and suggest chaotic motion. A similar series of events can be induced in the absence of periodic stimulation, when a control parameter is changed to various constant levels. The data suggest that the system is governed by deterministic dynamical laws.

1-Methyl-3-isobutylxanthine↗
PubMed1990

The lifetime of photosensory signals in Halobacterium halobium and its dependence on protein methylation.

Halobacteria spontaneously reverse their swimming direction about every 10 s. This behavioral pattern is transiently disturbed upon stimulation through sensory photosystems of different spectral sensitivity. As a result of stimulation, a single swimming interval is either prolonged (attractant response) or shortened (repellent response). Thereafter the cell returns to its autonomous reversal rhythm, i.e., it quickly adapts. Method are presented to determine the lifetime of repellent as well as of attractant cellular signals at the site of signal integration, using particular stimulation programs. Independent of the photosystem through which the signals were generated, the total lifetime of a repellent signal was 1.3 s. The decay of the signal was rapid during the first 100 ms and slow thereafter. The lifetime of an attractant signal was about 4 s and likewise did not depend on the photosystems. The degree of methylation of membrane proteins was increased by attractant stimuli and decreased by repellent stimuli. Inhibition of protein methylation by homocysteine was accompanied by a slowdown of the decay of both the repellent and attractant signal. A mutant strain with an increased demethylation also gave increased signal lifetimes. A lowered Ca2+ concentration, which activates methylation in vivo, led to shortened signal lifetimes. Methylation is proposed to be the mechanism which limits the signal lifetime and thereby allows the cells to adapt.

Bacterial Proteins↗
PubMed1987

Role of the response oscillator in inverse responses of Halobacterium halobium to weak light stimuli.

Under certain conditions Halobacterium halobium organisms respond to a weak attractant light stimulus with a repellent response and to a weak repellent stimulus with an attractant response. The appearance of inverse responses depends on the stimulus strength, on the interval length between spontaneous reversals, and on the moment of stimulation during the interval. Although the cells are absolutely refractory to repellent stimuli for 500 ms after a reversal, repellent responses can be evoked even during that period if they are inverse responses to weak attractant stimuli. Simultaneous attractant and repellent stimuli cancel each other even when one of them leads to an inverse response, indicating that normal cellular signals occur at the site of signal integration. We postulate that the inverse responses are caused by certain properties of a cellular oscillator for which we previously postulated a role in response regulation and sensory control in halobacteria (A. Schimz and E. Hildebrand, Nature [London] 317:641-643, 1985).

Halobacterium↗
PubMed1986

Entrainment and temperature dependence of the response oscillator in Halobacterium halobium.

Halobacterium halobium spontaneously reverses its swimming direction with a frequency of about 0.1 s-1. The self-sustained periodicity can be entrained by rhythmic light stimuli within a limited range between 0.13 and 0.3 s-1. Increase of temperature increases the reversal frequency and shortens the time to reach maximal responsiveness to attractant stimuli during a cycle. Also, the period of absolute refractoriness to repellent stimuli is shortened. The results illustrate characteristic properties of biological oscillators.

Halobacterium↗
PubMed1986

Integration of photosensory signals in Halobacterium halobium.

Stimulation of Halobacterium halobium through its sensory photosystems, PS 370 and PS 565, leads either to a prolonged or to a shortened interval between two reversals of the swimming direction of the cell, the attractant or repellent response. Stimuli are integrated to yield the same response regardless through which photosystem they are given. Simultaneously elicited attractant and repellent signals cancel each other at any time during a reversal interval, even in the period of refractoriness shortly after a reversal, when the cell is insensitive to repellent stimuli. Successively applied stimuli are less completely integrated. The net response depends on the moment of stimulation during the interval, on the sequence of stimuli, and on the delay between them. Integration of successively applied effective stimuli (after refractoriness) is to a great extent explained in terms of a cellular oscillator (A. Schimz and E. Hildebrand, Nature [London] 317:641-643, 1985) which is changed in opposite directions by attractant and repellent signals. Some conclusions on the shape of the oscillator after its disturbance by a stimulus can be made. Integration of signals during refractoriness leads us to postulate an additional step before the oscillator in the sensory pathway. Cancelling of simultaneous opposite signals is thought to proceed at this integrator. It also takes part in the integration of successively evoked signals. At this step signals rapidly decline within 10 ms, and the total life time (at least of repellent signals) does not exceed 1.2 s.

Flagella↗
PubMed1983

The endoscopic multiple-diameter bougie--clinical results are after one year of application.

A new technique for dilation of the upper gastrointestinal tract permits complete endoscopic control of the whole procedure for the first time. 113 dilations have been carried out in 37 patients within a period of 15 months. The endoscopic guidance of the multiple diameter bougie positively excludes perforation resulting from the bougie's going the wrong way. With the steerable tip of the endoscope, kinking can be overcome and stenoses down to the duodenum can be dilated.

Dilatation↗
PubMed1981

Electrically induced Ca2+ transport across the membrane of Paramecium caudatum measured by means of flow-through technique.

Transmembrane calcium fluxes related to excitation were studied in Paramecium caudatum. Radioactive (45Ca2+) or inactive solution was flowed through a dense suspension of unlabelled or labelled cells, and radioactivity was monitored in the solution. The organisms were electrically stimulated by means of extracellular electrodes. As a result of stimulation Ca2+ uptake and release was measured. The uptake response dropped with increasing number of successive stimulation periods and increased with growing stimulus amplitude and duration. Maximum uptake was obtained at 20 V/cm and at least 60 s duration and for temperatures between 10 and 15 degrees C. A Ca2+ influx of 700 pmol/1000 cells upon 1 min stimulation was measured at 15 degrees C. This corresponds to an increment of the intraciliary [Ca2+] of about 5 x 10(-4) M. Ca2+ release was dependent on the stimulus amplitude in a similar manner as was Ca2+ uptake. Photographic recordings of the swimming behaviour of the organisms were used to interpret the flux data. At temperatures up to 15 degrees C the cells swam backward perpendicular to the applied electric field of 10 to 20 V/cm. At 25 degrees C they showed forward spiralling movement. For the first time evidence was brought for stimulated Ca2+ influx in Paramecium at physiological temperatures. It is concluded from the results that a strong active Ca2+ extrusion from the intraciliary space counteracts the influx. The Ca2+ pump rate must be at least 8 x 10(12) calcium ions per s per cm2 ciliary surface.

Animals↗
PubMed1979

Chemosensory responses of Halobacterium halobium.

Responses of Halobacterium halobium cells to chemical stimuli have been shown by a capillary technique. Cells were attacted by D-glucose and several amino acids and repelled by phenol. Certain chemicals, such as acetate, benzoate, indole, and NiSO4, that are known to act as repellents of Escherichia coli cells served as attractants for Halobacterium. In the presence of ethionine, sensitivity to attractants was reduced. Arsenate prevented the attraction by glucose without lowering the cellular adenosine 5'-triphosphate level. The ability for chemo-accumulation toward glucose and histidine was interfered with by the formation of photosensory systems. Light-induced motor responses and chemosensory behavior toward glucose and histidine became detectable in the late stationary growth phase only. The behavior toward acetate and indole was not connected to photobehavior in that way: both substances acted as attractants already in the late log phase. Inhibition of bacteriorhodopsin synthesis by L-nicotine allowed chemo-accumulation toward glucose and histidine already in the late logarithmic phase.

Adenosine Triphosphate↗