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S Grund

Publications and source records attributed to S Grund.

At least 19 recordsLinked to original sources
PubMed2003

Extrapolation to zero-flow pressure in cerebral arteries to estimate intracranial pressure.

BACKGROUND: Cerebral perfusion pressure (CPP) is commonly calculated from the difference between arterial blood pressure (AP) and intracranial pressure (ICP). ICP can be considered the effective downstream pressure of the cerebral circulation. Consequently, cerebral circulatory arrest would occur when AP equals ICP. Estimation of AP for zero-flow pressure (ZFP) may thus allow estimation of ICP. We estimated ZFP from cerebral pressure-flow velocity relationships so that ICP could be measured by transcranial Doppler sonography. METHODS: We studied 20 mechanically ventilated patients with severe head injury, in whom ICP was monitored by epidural pressure transducers. AP was measured with a radial artery cannula. Blood flow velocity in the middle cerebral artery (V(MCA)) ipsilateral to the site of ICP measurement was measured with a 2 MHz transcranial Doppler probe. All data were recorded by a microcomputer from analogue-digital converters. ZFP was extrapolated by regression analysis of AP-V(MCA) plots and compared with simultaneous measurements of ICP. RESULTS: ZFP estimated from AP-V(MCA) plots was linearly related to ICP over a wide range of values (r=0.93). There was no systematic difference between ZFP and ICP. Limit of agreement (2 SD) was 15.2 mm Hg. Short-term variations in ICP were closely followed by changes in ZFP. CONCLUSION: Extrapolation of cerebral ZFP from instantaneous AP-V(MCA) relationships enables detection of severely elevated ICP and may be a useful and less invasive method for CPP monitoring than other methods.

Blood Pressure↗
PubMed2002

[The Wearable Cardioverter Defibrillator (WCD) for the prevention of sudden cardiac death -- a single center experience].

The Wearable Cardioverter Defibrillator (WCD) is an external defibrillator that automatically detects and treats ventricular tachyarrhythmias without the need for assistance from a bystander while at the same time allowing the patient to ambulate freely. The main components of the system are the defibrillator unit and a chest belt with electrodes for arrhythmia detection and therapy delivery. Between December 1998 and October 2001, 84 patients used the device at our institution. The majority of patients had a history of acute myocardial infarction or coronary artery bypass surgery with an increased risk for sudden cardiac death or were awaiting heart transplantation. During a mean follow-up of 116+/-90 days, 7 episodes of ventricular tachyarrhythmias were detected and terminated successfully by the WCD in 5 patients. In 9720 days, there was one inappropriate shock due to oversensing of electrical noise. Four patients died during follow-up; none of them had a cardiac arrest while wearing the device. Five patients were excluded because of irregularities in device use. An ICD was implanted in 24 patients at the end of the follow-up period. The WCD is effective in detecting and treating ventricular tachyarrhythmias in patients with an intermittently increased risk for sudden cardiac death. Further use of the system in larger patient populations is needed to confirm its safety and cost effectiveness.

Aged↗
PubMed2000

Cerebrovascular tone rather than intracranial pressure determines the effective downstream pressure of the cerebral circulation in the absence of intracranial hypertension.

Cerebral perfusion pressure is commonly calculated from the difference between mean arterial pressure and intracranial pressure because intracranial pressure is known to represent the effective downstream pressure of the cerebral circulation. Studies of other organs, however, have shown that effective downstream pressure is determined by a critical closing pressure located at the arteriolar level. This study was designed to investigate the effects of PCO2-induced variations in cerebrovascular tone on the effective downstream pressure of the cerebral circulation. Sixteen patients recovering from head injury were studied. Intracranial pressure was assessed by epidural pressure transducers. Blood flow velocity in the middle cerebral artery was monitored by transcranial Doppler sonography. Effective downstream pressure was derived from the zero flow pressure as extrapolated by regression analysis of instantaneous arterial pressure/middle cerebral artery flow velocity relationships. PaCO2 was varied between 30 and 47 mm Hg in randomized sequence. Intracranial pressure decreased from 18.5+/-5.2 mm Hg during hypercapnia to 9.9+/-3.1 mm Hg during hypocapnia. In contrast, effective downstream pressure increased from 13.7+/-9.6 mm Hg to 23.4+/-8.6 mm Hg and exceeded intracranial pressure at hypocapnic PaCO2 levels. Our results demonstrate that, in the absence of intracranial hypertension, intracranial pressure does not necessarily represent the effective downstream pressure of the cerebral circulation. Instead, the tone of cerebral resistance vessels seems to determine effective downstream pressure. This suggests a modified model of the cerebral circulation based on the existence of two Starling resistors in a series connection.

Adult↗
PubMed1999

Treponema brennaborense sp. nov., a novel spirochaete isolated from a dairy cow suffering from digital dermatitis.

A novel Treponema species was isolated from an ulcerative lesion of a cow suffering from digital dermatitis (DD), a disease which causes painful ulcerations along the coronary band. Among other anaerobic bacteria, high numbers of spirochaetes have been regularly found in DD lesions. Here data are presented of a spirochaete isolated from a DD ulcer. By chemotaxonomy, protein analysis and comparative 16S rDNA sequence analysis this isolate was classified as a treponeme that differed from all Treponema species described previously. The only isolate, DD5/3T, for which the name Treponema brennaborense is proposed, is designated the type strain of the novel species. The strain is a small, highly motile spirochaete that has two periplasmic flagella, one flagellum being attached at each cell pole. Strain DD5/3T exhibits alpha-glucosidase and N-acetyl-beta-glucosaminidase activity and growth is inhibited by rabbit serum. T. brennaborense was phylogenetically most closely related (89.5% 16S rRNA similarity) to Treponema maltophilum, an oral spirochaete isolated from a periodontitis patient.

Animals↗
PubMed1997

Spirochetes from digital dermatitis lesions in cattle are closely related to treponemes associated with human periodontitis.

Digital dermatitis (DD), first described in 1974 by Cheli and Mortellaro (R. Cheli and C. Mortellaro, p. 208-213, in Proceedings of the 8th International Conference on Diseases of Cattle, 1974), is a major problem in diary cows and beef cattle causing significant economic losses worldwide. Lesions are typically found at the volar skin proximal to the heel bulbs. Microscopic examination of biopsies or touch preparations of these lesions revealed a variety of different bacterial morphotypes including significant numbers of spirochetes which often represent the predominant morphotype. We used comparative 16S rRNA sequence analysis to determine the diversity and phylogeny of these hitherto unclassified DD spirochetes. Results indicate that those lesions looked at so far contained at least five spirochetal phylotypes, all clustering within the genus Treponema. Phylotype DDKL-4 was nearly identical (99.4% similarity) to that of a nonpathogenic human treponeme, T. phagedenis. Two phylotypes DDKL-3 and DDKL-13 were closely related to those from treponemes commonly found in human periodontitis lesions, i.e., T. denticola and T. vincetii, exhibiting 95 and 98% similarity, respectively. The other two phylotypes, DDKL-12 and DDKL-20, had no close relatives to any cultivable treponemal species but clustered to previously described group IV oral treponemes. Preliminary analysis using in situ hybridization with fluorescently labeled oligonucleotide probes against smears from DD biopsies revealed that from all lesions analyzed so far, T. denticola-like spirochetes were detected in the highest proportion of all spirochetal morphotypes.

Animals↗
PubMed1997

[Vaccination of pigeons against Salmonella infections].

The efficiency of the live vaccine Zoosal T with a double marker mutant of Salmonella Typhimurium was tested on conditioned pigeons. For challenge infection we used a pigeon specific variation copenhagen strain in a defined state of virulence. The reduction of mortality and the persistence of Salmonella in organs were evaluated. An oral booster enhances the protection due to vaccination.

Animals↗
PubMed1995

[Electron microscopic detection of spirochetes in dermatitis digitalis of cattle].

In typical Dermatitis digitalis (D.d.) lesions, spirochaete-like bacteria with variations in spiralization were revealed by electron microscopy. While, in the early stages of the disease, these are found to be associated with fibrillar material of keratocytes, they occur massively in vacuoles at more advanced stages. The spirochaetes carry one pair of endoflagella, originating with a hook from the poles of the bacteria. These flagellae are composed of coiled flagellating fibrils in the pole region, merging towards the centre of the bacterium. A coat of fibrils was found in association with the cytoplasmatic membrane. The winding of this coat follows and may influence the coiling of the protoplast, and is probably involved in the rapid motility of this spirochaetes, together with the flagella. Immuno-electronmicroscopy revealed an antigenic relationship with Borrelia burgdorferi, at least with regard to the regions of flagella and undulating membrane. The paper discusses: 1. The possible classification of these spirochaetes with the genus Treponema; 2. The layer of peptidoglycan occurring on the outer membrane; and 3. The keratolytic activity of spirochaetes in D.d.

Animals↗
PubMed1994

Purification and partial characterization of type 3 fimbriae from Salmonella typhimurium var. copenhagen.

Aggregative thin fimbriae from a pigeon pathogen, Salmonella typhimurium var. copenhagen (STMVC) Mö 8 were isolated and purified. These fimbriae remained associated with the cells even after attempts to separate them from blended cells by centrifugation. After purification, fimbriae and little cell fractions were polymerized in formic acid and then analyzed by SDS-PAGE. This pretreatment resulted in the appearance of a main protein band of 17 kDa. The N-terminal amino acid sequence of 19 residues of purified 17 kDa protein showed considerable homology with the N-terminal sequence of thin fimbriae of S. enteritidis. Native fimbriae on whole cells were specifically labelled with immune serum raised to the purified fimbriae. This immune serum also reacted with the denatured 17 kDa protein in Western blots. The polyclonal immune serum did not cross-react with the type-1 fimbriae produced by STMVC.

Amino Acid Sequence↗
PubMed1994

[Detection of atypical toxin-producing Pasteurella strains on the nasal mucosa of calves and their differential diagnostic limits for Pasteurella haemolytica and Pasteurella multocida].

The bacterial colonisation on nasal mucous membranes of calves at age of 3, 5 to 5 months was investigated by cotton swabs. Three Pasteurella species were found (P. multocida subspecies multocida, P. haemolytica, P. avium) as monocausal infection as well as pluricausal infection. P. avium was characterised by colonial morphology, bacterioscopy, biochemical properties, polypeptide-pattern in SDS-PAGE and by electronmicroscopic investigation and was differentiated from P. multocida and P. haemolytica. It is very interesting, that the P. avium strains possess an antigen structure, reacting with monoclonal antibodies directed against the heat labile-toxin of P. multocida subspecies multocida.

Animals↗
PubMed1993

[Electron microscopic studies of fimbriae and lectin phagocytosis of Salmonella typhimurium variety copenhagen (STMVC)].

On Salmonella typhimurium variatio copenhagen (STMVC) strains, isolated from pigeons with acute Salmonellosis, two types of fimbriae can be identified, depending on different growth conditions. In addition to the common 7 nm fimbriae we were able to demonstrate in the electron microscope, thin, curled fimbriae 3 nm in diameter which are characterized by a mannose-resistant hemagglutination. The simultaneous expression of both types of fimbriae on a single bacterial cell can be induced by transferring a microcolony from agar medium (3 nm fimbriae), to the surface of a nutrient broth (7 nm fimbriae) and continuing the incubation. One selected strain expresses only the thin fimbriae on nearly all the bacteria on an agar medium. These thin fimbriae seem to play a role in the lectinophagocytosis in macrophage cultures. The attachment of Salmonellae mediated by these fimbriae as well as the internalization of fimbriated cells by macrophages is shown in the electron microscope and discussed in respect to infection and immunization.

Animals↗
PubMed1992

Fimbriae and membranes on Haemophilus parasuis.

In the electron microscope an additional layer (glycocalix) of the cell wall and fimbriae on Haemophilus parasuis were shown in thin sections of the infected CAM which have their origin on the CM of the Haemophilus parasuis-cells. No fimbriation was seen after conventional cultivation.

Animals↗
PubMed1991

Slime capsule and fimbriae on Salmonella typhimurium var. cop.--electron microscopic study.

On Salmonella typhimurium var. cop. we found, under special culture conditions, on the same cell simultaneously fimbriae and mucoid material which was histochemically identified as an acid mucopolysaccharide. Membrane vesicles or invaginations of the cytoplasmic membrane are mentioned as a possible place of the slime production and the function of the glycocalyx is discussed regarding tenacity, as a diffusion barrier and attachment factor.

Animals↗
PubMed1991

[Therapeutic use of fresh plasma and "virus-safe" plasma].

The use of plasma and factor concentrates for the treatment of coagulation disorders is well established, but many questions remain. The indications for fresh frozen plasma are still not clearly established and excessive use is rampant. The safety of all blood products has not yet been firmly established. Peer review of transfusion practice in a hospital can be achieved by a Hospital Transfusion Committee. The review and analysis of the statistical reports of the transfusion service and strategies for enhancing quality of patient care will be presented.

Algorithms↗
PubMed1990

[Pasteurella multocida (type D and A) and atrophic rhinitis of swine--hemagglutination, fimbriae and adhesion in vitro in the nasal mucosa of swine fetuses].

79 strains of P. multocida were investigated, mostly isolated from porcine nasal cavities, and a mannose-resistant hemagglutination with guinea pig and human group 0, but not with porcine erythrocytes was found. Fimbriae as adhesins were demonstrated only on 2 strains. A correlation between capsular type, hemagglutination, fimbriation and toxigenicity on the examined P. multocida strains was not observed. Three strains were investigated for the adherence to the nasal mucosa of neonatal pigs; aggregates shown by scanning electron microscopy indicate colonization; a correlation of adherence with surface proteins and slime production of P. multocida is discussed.

Animals↗
PubMed1990

[Electron microscopic studies of mucosal extirpates of rabbits after after in vitro contact with Pasteurella multocida subsp. multocida strains].

In vitro experiments of adhesion and colonisation of mucosal surface fragments (nose, trachea) from freshly killed rabbits with four strains of Pasteurella multocida subsp. multocida with different types of capsule antigen (A, D, without capsule) showed the following results: Above all the capsule serovar A strain, producing a capsule of hyaluronic acid and fimbria, were able to adhere and to form microcolonies on the mucosal surface. Microvilli of epithelial cells and mucus producing cells were recognized as the place of adhesion. The formation of microcolonies occurred with a destruction of the kinocilia, which was caused by a bacteria free culture filtrate as well.

Animals↗