Biomedical subjects

M Hauck

Publications and source records attributed to M Hauck.

At least 19 recordsLinked to original sources

PubMed2003

[Laser-evoked potentials: diagnostic approach to the dorsal root].

Functional diagnostics of the dorsal root are especially effective via nociceptive fibers on account of less intersegmental overlap compared to large-diameter fibers of the mechanoreceptive afferents. Laser-evoked potentials (LEP) are induced by short, painful heat stimuli. The aim of this work was to describe changes of the LEP in cases of dorsal root damage. The recorded LEP changes will be discussed with regard to their prognostic value as well as pathophysiologic aspects of dorsal root damage. Dorsal root function was tested in 21 patients suffering from clinically proven radiculopathy in one of the segments L4 to S1. Mechanosensibility and thermosensibility were clinically investigated. LEP were induced by slightly painful stimuli (80 on the affected and 80 on the contralateral unaffected dermatome). The LEP were evaluated by amplitude of the averaged electroencephalogram (EEG). In addition, a subjective pain rating was recorded after each stimulus. Investigation of dorsal root function by LEP in patients with radiculopathy yields two typical changes of the amplitude. On the one hand, there were significant reductions of amplitude, and on the other hand, a complete loss of LEP was found. LEP changes allow a graduation of patients who show no obvious differences in their clinical appearance. Which mechanisms are responsible as concerns deafferentiation and neuropathy of the dorsal root fibers are discussed. With regard to the LEP changes, a prognostic relevance in patients with dorsal root affections is likely. This question will be addressed in a prospective study soon.

Adult↗

PubMed2001

Relevance of element content of bark for the distribution of epiphytic lichens in a montane spruce forest affected by forest dieback.

Element content in the bark on Norway spruce (Picea abies) was measured in a montane forest heavily affected by forest dieback and compared to that in a nearby intact stand. Bark contained less S, K, Fe, Mn, Pb, Cu, and H+ and more N, Ca, Mg, and Zn in the dieback-affected stand than in the intact one. Diversity of epiphytic lichen vegetation was higher in the dieback-affected stand than in the intact one. Cover of the foliose lichen Hypogymnia physodes was negatively correlated with Mn and Cu content of bark. Cover of the extremely acidophytic species Lecanora conizaeoides decreased with increasing Mg and increased with increasing Cu content of bark. The measurements support the hypothesis that chemical site factors are decisive for the high lichen diversity in dieback-affected montane spruce forests.

Environmental Monitoring↗

PubMed2001

Age-related alterations in the signal transduction pathways of the elastin-laminin receptor.

With aging we assist to alterations in the vascular structure and function. One important factor in these vascular wall changes is the degradation of the elastin fibre major protein: elastin. Elastin peptides derived from the degradation are present in human sera. Elastin peptides induce on fibroblasts, phagocytic cells, lymphocytes, smooth muscle cells and endothelial cells, a variety of biological effects mediated by the elastin-laminin receptor which has been demonstrated to be present on the membrane of these cells. The transduction pathway of the ELR receptor involves the activation of phospholipase C (PLC) by a pertussis toxin sensitive G-protein. PLC induces the production of inositol trisphosphate (IP3) leading to the increase of the intracellular free calcium on one hand, and of diacylglycerol (DAG) which stimulates the translocation to the membrane of PKC leading to the phosphorylation of members of the MAPK family, such as p42/p44 MAPK. A progressive age dependent uncoupling of the elastin-laminin receptor occurs impairing its transduction pathway and which results in alteration of the calcium signaling and loss in calcium homeostasis of the cells. These alterations in the signal transduction of the elastin-laminin receptor result in modified activities of parenchymal and phagocytic cells with aging, such as free radical production and elastase release. Thus, these age-related alterations in the elastin-laminin receptor signal transduction may be involved in the atherogenesis.

Aging↗

PubMed2001

[The elastin-laminin receptor].

Elastin is a major component of the extracellular matrix. Elastin peptides derived from its degradation are present in human sera. Elastin peptides induce on fibroblasts, phagocytic cells, lymphocytes, smooth muscle cells and endothelial cells, a variety of biological effects mediated by the elastin-laminin receptor which has been demonstrated to be present on the membrane of these cells. The transduction pathway of the ELR receptor involves the activation of phospholipase C (PLC) by a pertussis toxin sensitive G-protein. PLC induces the production of inositol trisphosphate (IP3) leading to the increase of the intracellular free calcium on one hand, and of diacylglycerol (DAG) which stimulates the translocation to the membrane of PKC leading to the phosphorylation of members of the MAPK family, such as p42/p44 MAPK. Considering the multiple biological effects of ELR the elucidation of the complexity of the signaling pathways will help to better modulate it, mainly in pathological situations such as atherosclerosis.

Animals↗

PubMed1998

Effect of omental angiogenic lipid factor on revascularization of autotransplanted spleen in dogs.

Since the turn of the century, studies have been carried out showing that the omentum contains a factor which enhances revascularization of ischemic tissues. This study was conducted for a period of 3 months and was designed to evaluate the effect of an omental lipid fraction on neovascularization of autotransplanted spleen chips in dogs. Twelve dogs underwent splenectomy and autotransplantation of 5 splenic chips into an omental pouch. In 4 dogs, the splenic chips were immersed in omental angiogenic lipid factor (OAF), while on another 4 dogs, an intramuscular injection of 4 cm3 of OAF was given each day for 7 days postoperatively. A further 4 dogs were not given any of the above treatments (control group). Serial angiographies and histologic examinations demonstrated better neovascularization and regeneration of the transplanted spleen in the dogs from the immersion plus injection group. These data suggest that the omental lipid fraction contains a factor which induces a better regeneration of splenic transplants.

Angiogenesis Inducing Agents↗

PubMed1998

Effect of gamma-hydroxybutyrate on pain, fatigue, and the alpha sleep anomaly in patients with fibromyalgia. Preliminary report.

OBJECTIVE: To evaluate the effects of using a gamma-hydroxybutyrate (GHB) administered in divided doses at night in 11 patients previously diagnosed with fibromyalgia (FM). METHODS: Subjects completed daily diaries assessing their pain and fatigue levels and slept in the sleep laboratory before and one month after initiating GHB treatment. Polysomnographic recordings were evaluated for sleep stages, sleep efficiency and the presence of the alpha anomaly in non-REM sleep. RESULTS: There was a significant improvement in both fatigue and pain, with an increase in slow wave sleep and a decrease in the severity of the alpha anomaly. CONCLUSION: Further controlled studies are needed to characterize the clinical improvement and the polysomnographic changes we observed.

Adult↗

PubMed1997

Caring for children and adults on a specialty unit.

The nursing care system in a university hospital was modified to accommodate children on an organ transplant unit. System components for ensuring high-quality care for patients of all ages are identified and described. Primary nursing, a Pediatric Nursing Practice Council, Child Family Life and the support of the health care team are incorporated to successfully care for adults and children on this specialty unit.

Adult↗

PubMed1997

Protection of the renal artery in nephron-sparing surgery. II. Arterial contractility investigations.

It has been well known that reperfusion following ischaemia may cause functional and structural damage to not only the organ involved but also the blood vessels supplying that organ. As in organ-sparing renal surgery it is inevitable to clamp the renal artery for some time, it is expected that reperfusion, following the removing of clamping, causes structural changes in the vessel wall which may result in a decrease in arterial function. In our model experiments on animals, the left renal arteries were atraumatically clamped for 30, 45 and 60 minutes. Simultaneously with clamping, perfusion regional renal venous cooling was applied to some of the animals, together with nephrotomy. In some cases cooling was performed in combination with antioxidant treatment. On the 3rd postoperative day renal arteries from both sides were removed, the right, intact ones serving as control. Noradrenaline dose effect curves characterizing vessel contractility were determined to demonstrate functional changes. It was established that cooling the renal artery for only 30 minutes was enough to rule out the damage due to ischaemia-reperfusion. If clamping lasted for 45 minutes, venous cooling of the kidney in combination with antioxidant treatment was necessary to spare arterial function. Clamping for 60 minutes resulted in irreversible/permanent decrease in contractility even if hypothermia and antioxidant treatment were given simultaneously.

Animals↗

PubMed1997

Investigation of microcirculatory changes in the duodenum of dogs caused by surgical suture materials.

Surgical suture materials play an important role in the safe performance of surgical interventions. In our experiments we made an attempt to investigate what microcirculatory changes result from pulling the thread through the wall of the duodenum in Lembert stitches by including 3 kinds of absorbable and non-absorbable suture materials each (Catgut, Dexon, PDS, Silk, Ethibond, Ethilon). Research is still in the pre-experimental stage. In the long run, we hope to enrich the description of these suture materials by some new details. It could help prevent suture insufficiency, facilitate wound healing and thus, improved surgical safety.

Absorption↗

PubMed1996

Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results

INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet.

Journal Article↗

PubMed1996

Bright Spots, Structure, and Magmatism in Southern Tibet from INDEPTH Seismic Reflection Profiling

INDEPTH seismic reflection profiling shows that the decollement beneath which Indian lithosphere underthrusts the Himalaya extends at least 225 kilometers north of the Himalayan deformation front to a depth of approximately 50 kilometers. Prominent reflections appear at depths of 15 to 18 kilometers near where the decollement reflector apparently terminates. These reflections extend north of the Zangbo suture to the Damxung graben of the Tibet Plateau. Some of these reflections have locally anomalous amplitudes (bright spots) and coincident negative polarities implying that they are produced by fluids in the crust. The presence of geothermal activity and high heat flow in the regions of these reflections and the tectonic setting suggest that the bright spots mark granitic magmas derived by partial melting of the tectonically thickened crust.

Journal Article↗

PubMed1996

Laparoscopic implantation of temporary electrodes for bladder stimulation in dogs.

Five female mongrel dogs were used in an acute animal experiment. Under general anesthesia two monopolar wire electrodes armed with needles on either side were implanted into the bladder wall, the leads of both electrodes were then pulled through the abdominal wall. Filling of the bladder and intravesical pressure measurement were achieved through a suprapublic percutaneous cystostomy. Electrostimulation was carried out using the XEJ-2 experimental electroejaculator (biphasic pulses, pulse width 2.5 msec, approximately 70 mAmp, 50 Hz). The pressure changes within the bladder following electrostimulation were recorded, the effect of stimulation was observed endoscopically. Electrostimulation of the bladder wall resulted in micturition in all cases, showing an initial pressure peak at the commencement of electrostimulation followed by a decrease after onset of evacuation. We believe that laparoscopic implantation of temporary wire electrodes followed by percutaneous electrostimulation may open up new possibilities for bladder rehabilitation as well as for diagnostic investigations into the contractile capabilities of the bladder.

Animals↗

PubMed1996

The Louisiana State University Comprehensive Epilepsy Program: procedures and outcomes.

The first comprehensive epilepsy surgery center in Louisiana was established in 1990 at the Louisiana State University Medical Center in New Orleans by the Departments of Neurology and Neurosurgery. The center performs a wide variety of diagnostic tests essential for the medical and surgical treatment of epilepsy including EEG and video monitoring, quantitative hippocampal MRI volumetry, ictal SPECT brain scanning, intracranial evoked potential and subdural stimulation functional mapping, neuropsychological evaluations, and intracarotid amobarbital (Wada) language and memory localization. Surgical interventions include (1) the placement of subdural strip and grid electrodes, depth electrodes, and foramen ovale electrodes, (2) temporal lobectomies, and (3) frontal, temporal, parietal, and occipital lobe resections. From August 1990 through October 1995 41 patients with medically intractable seizures underwent neurosurgical procedures for epilepsy. Thirty-five patients had resective surgery, while six had only intracranial monitoring by subdural or intracerebral electrodes. The surgical outcomes thus far compare favorably with those of other established centers in North America.

Adolescent↗

PubMed1996

Effect of glucagon and somatostatin on pancreatic secretion in dogs.

The authors investigated the effects of glucagon and a somatostatin preparation (Stilamin) on the secretion volume and on the secreted and absorbed enzyme levels of the pancreas. Four groups of dogs with an artificial pancreatic fistula were given a single intravenous injection of glucagon (group I, n = 8), intravenous drip-infusion of glucagon (group II, n = 8), intravenous drip-infusion of somatostatin (group III, n = 10) and intravenous drip-infusion of the carrier fluid, physiological sodium-chloride (control, group IV, n = 5), respectively. Pancreatic juices were collected and volume, pH, bicarbonate, amilase, lipase, trypsin and protein contents were determined. Serum amilase and lipase levels before and at the termination of the experiment were also measured. Intravenous drip-infusion of both Glucagon and Stilamin decreased pancreatic secretion, Stilamin being more effective than Glucagon. On the other hand, a single i.v. injection of Glucagon resulted in an increased secretion. The authors suggest that based on the observed inhibitory effect on pancreatic secretion, both glucagon and somatostatin could be used to reduce postoperative complications of pancreatic operations in the clinical practice.

Amylases↗

PubMed1995

Social initiations by autistic children to adults and other children.

Social initiations made by autistic and verbal-matched retarded children were recorded in two naturalistic situations. Frequencies of initiation to adults did not differ between groups, but the retarded children initiated much more frequently to peers. Most interactions for both groups were positive, but the autistic children engaged in more ritualized, and the retarded children more playful, initiations. The autistic children monitored the social environment more when forced into proximity with peers, whereas the retarded children initiated more in the unstructured situation. Autistic initiation to peers was unrelated to severity of autism, but was related to cognitive skills, including vocabulary and comprehension of affect, whereas retarded children's initiations were unrelated to cognitive level. Results are discussed in terms of the differences between adults and children as social stimuli, prerequisite skills for initiation to peers, and the relationship between social cognition and social behavior. It is suggested that autistic and retarded children differ in the quantity of their initiations to peers, and the quality of their initiations to adults, and that initiations to peers may be a particularly useful index of social development in autistic children. Results confirm the need of autistic children for highly structured social environments, and suggest an important role for the remediation of specific cognitive skills such as comprehension of others' affects.

Adolescent↗

PubMed1995

Effects of synthesized elastin peptides on human leukocytes.

It is well demonstrated that various peptides derived from elastin are biologically active. The hexapeptide (Val-Gly-Val-Ala-Pro-Gly; VI) as well as elastin peptides were demonstrated to be chemotactic for fibroblasts, while kappa-elastin had marked biological effects on human PMNLs. The aim of our present work was to synthesize various elastin peptides and compare their action to that of kappa-elastin and this hexapeptide. The results indicate that the hexapeptide (Val-Gly-Val-Ala-Pro-Gly) and the two other synthesized hexapeptides (Pro-Gly-Val-Gly-Val-Ala; III and Val-Gly-Val-Gly-Val-Ala; IV) had very similar and specific effects on intracellular free calcium metabolism, on superoxide anion production and elastase release. The other peptides had no effects on these parameters, except a tripeptide (Val-Gly-Val; V) on superoxide anion production. Moreover, the effect of the hexapeptides (III and VI) could be abolished by Pertussis toxin preincubation. All peptides had very similar stimulating effects on H2O2 production and myeloperoxidase release. We conclude that most probably the peptide size and conformation, as well as peptide composition play a role in the biological effects of these peptides, through specific receptors on PMNLs surface.

Amino Acid Sequence↗

PubMed1992

Transmembrane signaling changes with aging.

Altered immune response and transmembrane signaling with aging has previously been demonstrated. The aim of the present study was to characterize PMNLs and lymphocyte G proteins and to determine whether their relative amounts are altered with aging. First we studied the effects of FMLP on PMNLs IP3 formation. It was found that in any group of elderly the PMNLs IP3 formation was significantly decreased compared to that of young subjects. In FMLP receptor binding affinity no measurable difference exists in either low- or high-affinity FMLP receptors. The autoradiogram of 32P-ADP-ribosylated proteins by CT in lymphocytes of young individuals showed a major polypeptide of 40 kDa, and two much less prevalent components of 52 and 45 kDa. In contrast, in lymphocytes of elderly subjects the major polypeptide was 45 kDa, and the two others were very weakly labeled. In PMNLs, CT labeled the 45-kDa band quite strongly, mainly in the elderly, and the 52- and 40-kDa bands were very weakly labeled, mainly in young subjects. When PT was used, no age-related pattern changes could be demonstrated, while differences could be observed between the two types of cells.

Adenosine Diphosphate Ribose↗

PubMed1992

Sera and leukocyte elastase-type protease and antiprotease activity in healthy and atherosclerotic subjects of various ages.

Serum and granulocyte elastase-type protease activities were determined simultaneously with their main plasma proteinase inhibitors such as alpha-1-antitrypsin and alpha-2-macroglobulin in healthy control and atherosclerotic (ATS) subjects. The age-related associations of these parameters were also investigated. Serum elastase-type protease activity increased, but not statistically significantly, with aging in both control and ATS subjects. The enhancement of elastase-type protease activity in sera of ATS patients was significantly (p less than .02) greater than control subjects only in the case of the elderly. The granulocytes' elastase activity was significantly greater in granulocytes derived from both middle-aged and elderly ATS patients (p less than .03 and p less than .06) compared to age-matched control subjects. Alpha-1-antitrypsin was not significantly lower, whereas alpha-2-macroglobulin was significantly lower in sera of ATS subjects compared to age-matched control subjects (p less than .01). The conclusion is that increased elastase-type activity and decreased antiproteinase activity should be considered as potential factors in atherosclerotic arterial wall damage. The similarity of the results in the elderly and the ATS subjects suggest that atherosclerosis is an early aging process.

Adult↗