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Biomedical subjects

M Scherer

Publications and source records attributed to M Scherer.

At least 37 records · Page 2Linked to original sources
PubMed2000

Ascorbic acid for amelioration of reperfusion injury in a lung autotransplantation model in sheep.

BACKGROUND: Reperfusion injury is the leading cause of early graft dysfunction after lung transplantation. Activation of neutrophilic granulocytes with generation of free oxygen radicals appears to play a key role in this process. The efficacy of ascorbic acid as an antioxidant in the amelioration of reperfusion injury after lung transplantation has not been studied yet. METHODS: An in situ autotransplantation model in sheep is presented. The left lung was flushed (Euro-Collins solution) and reperfused; after 2 hours of cold storage, the right hilus was then clamped (group R [reference], n = 6). Group AA animals (n = 6) were treated with 1 g/kg ascorbic acid before reperfusion. Controls (group C, n = 6) underwent hilar preparation and instrumentation only. RESULTS: In group R, arterio-alveolar oxygen difference (AaDO2) and pulmonary vascular resistance (PVR) were significantly elevated after reperfusion. Five of 6 animals developed frank alveolar edema. All biochemical parameters showed significant PMN activation. In group AA, AaDO2, PVR, work of breathing, and the level of PMN activation were significantly lower. CONCLUSIONS: The experimental model reproduces all aspects of lung reperfusion injury reliably. Ascorbic acid was able to weaken reperfusion injury in this experimental setup.

Animals↗
PubMed2000

Parkin deletions in a family with adult-onset, tremor-dominant parkinsonism: expanding the phenotype.

A gene for autosomal recessive parkinsonism, PARK2 (parkin), has recently been identified on chromosome 6q and shown to be mutated in Japanese and European families, mostly with early-onset parkinsonism. Here we present a large pedigree from South Tyrol (a region of northern Italy) with adult-onset, clinically typical tremor-dominant parkinsonism of apparently autosomal dominant inheritance. Haplotype analysis excluded linkage to the chromosome 2p, 4p, and 4q regions that harbor genes associated with autosomal dominant parkinsonism, but implicated the parkin locus on chromosome 6q. Compound heterozygous deletions in the parkin gene (one large and one truncating) were identified in 4 affected male siblings. The patients were clinically indistinguishable from most patients with idiopathic Parkinson's disease. None of them displayed any of the clinical hallmarks described in patients with previously reported parkin mutations, including diurnal fluctuations, benefit from sleep, foot dystonia, hyperreflexia, and early susceptibility to levodopa-induced dyskinesias. Two affected female individuals carried one (truncating) of the two deletions in a heterozygous state with an apparently normal allele. We conclude that the phenotypic spectrum associated with mutations in the parkin gene is broader than previously reported, suggesting that this gene may be important in the etiology of the more frequent late-onset typical Parkinson's disease.

Age of Onset↗
PubMed1998

Purification and characterization of laccase II of Aspergillus nidulans.

Sexual development in Aspergillus nidulans is a morphogenetic differentiation process triggered by internal and environmental signals. As a first step in analyzing the developmental pathway at the molecular level, laccase II (EC 1.10.3.2), which is specifically expressed in early stages of fruitbodies, was isolated. The enzyme was purified to apparent homogeneity from a mutant strain (SMS1) in which the sexual cycle dominates and the number of cleistothecia is increased tenfold. Laccase II was enriched 560-fold to a specific activity of 892 U (mg protein)-1. The apparent molecular mass was determined to be 80 kDa under denaturing conditions and to be 100-120 kDa under native conditions. The internal peptide sequences gained from the protein will allow the isolation of the corresponding gene as a first step in determining the key regulators of sexual development.

Amino Acid Sequence↗
PubMed1998

Fundamental mechanisms of managed behavioral health care.

Making sense of managed behavioral health care organizations (MBHOs) is difficult as they rapidly evolve in response to payer, member, legislative, and market demands. This article describes the basic mechanisms involved in managed behavioral health care's evolution, including the nature of carve-out organizations, carved-in services, the array of payment mechanisms between payer and MBHO, and between MBHO and mental health care providers. Additionally, types of delivery systems and mechanisms used to control utilization are outlined in the context of continuing health care change.

Health Care Sector↗
PubMed1997

CD11b mRNA expression in neutrophils isolated from peripheral blood and gingival crevicular fluid.

Adhesion molecule CD11b/CD18 expressed by neutrophils (PMNs) participates in cell migration and phagocytosis of C3bi derivatized bacteria. It is this phagocytic function that eliminates some of the known periodontal pathogens in periodontal pockets. In patients with advanced periodontitis, homotypic aggregation of crevicular fluid PMNs (CF-PMNs) may occur due to overexpression of CD11b/CD18 and this may lead to ineffective elimination of periodontal pathogens. We have previously shown that CF-PMNs isolated from the periodontal pockets overexpress CD11b compared to PB-PMNs. This study tested the hypotheses that (1) overexpression of surface CD11b correlates with expression of CD11b mRNA in CF-PMNs isolated from advanced periodontitis subjects, and (2) the intrinsic capacity of CD11b mRNA upregulation by PB-PMNs from periodontitis patients differs from that of control subjects. CF-PMNs and peripheral blood PMNs (PB-PMNs) were isolated from 13 subjects with healthy gingiva (control group) and 13 subjects with advanced periodontitis (patient group). The surface expression of CD11b was determined by flow cytometry and CD11b mRNA was determined by extraction of mRNA and reverse transcription to cDNA followed by DNA amplification using primers to detect a segment of the cDNA which encodes CD11b. The results of this study confirm that the surface expression of CD11b on CF-PMNs is significantly higher in periodontitis subjects vs control subjects (p = 0.03), whereas surface CD11b expression on PB-PMNs does not differ significantly between groups (p = 0.06). The level of surface CD11b expression on CF-PMNs did not correlate with the amount of mRNA present in CF-PMNs in either group (p = 0.056, 0.07 for control and periodontitis patients, respectively). Most (9 of 13) individuals in the patient group expressed CD11b mRNA whereas very few control subjects (2 of 11) had CD11b mRNA in their CF-PMNs. This difference between groups was statistically significant (p = 0.004). The capacity to upregulate CD11b mRNA upon stimulation with fMLP and/or GM-CSF was highly variable and there was no statistical difference between the 2 groups.

Adult↗
PubMed1996

Technology transfer of neuroprosthetic devices.

Despite long development periods for neuroprosthetic devices, the numbers in clinical use or clinical trials are rising, with an estimated 3,000 systems in use today. As they gain experience with the regulatory approval process, developers are learning to conduct research to best prepare for transfer of technology to industry. The track record of the first motor prosthesis to be approved by the United States Food and Drug Administration contains important lessons for a company planning to undergo the regulatory process. Throughout the development of a neuroprosthesis, the capabilities and preferences of the customers who will use it (physicians, surgeons, therapists, and end-users) should be sought out and used in device design. When a device has reached clinical application, particular attention is needed to maximize both the population who will use it and each individual's degree of use (optimal, partial, reluctant). Identification of person-technology mismatches can help to select training strategies and other interventions that can be applied to ensure a good rehabilitation outcome.

Clinical Trials as Topic↗
PubMed1995

[Burden of fattening pigs and the environment of the pig fattening farms caused by lung-passing dust particles, pig stall specific bacteria and ammonia].

According for their topographic and isolated locations (no built-up area or trees down-wind) 13 fattening pig pens with an average stocking rate of 737 (360-2500) have been investigated for burden by immission of animals and the environment outside the stables up to a distance of 100m downwind of the source. These studies have been carried out between June 1988 and April 1989 in monthly intervals. The investigated parameters have been: dust of particle size < 5 microns, stable specific bacteria, ammonia and symptoms of animals respiratory diseases. In the stalls could be shown an significant seasonal influence on bacteria, lung passing dust content and ammonia concentration with a maximum during December/January (1.1 x 10(6) CFU/m3; 0.26 mg/m3; 27 ppm) and minimum during June/July (5.7 x 10(5) CFU/m3; 0.075 mg/m3; 11 ppm). In the environment outside the pigsties a significant seasonal influence could be found only for the stable specific bacteria up to the distance of 100m of the source of emission, showing a maximum during fall and winter (1.7 x 10(3) CFU/m3) and minimal concentration during spring and summer (9.3 x 10(2) CFU/m3). Due to emission of spent air a high significant reduction of the stable specific bacteria and lung passing dust concentration could be established outside the stables within a distance of 10 m. The content of stable specific bacteria come to 0.2% (1941 CFU/m3) compared with the amount measured at the air outlet of the spent air shaft. At this distance the lung passing dust concentration has been reduced to 11% (0.016 mg/m3) of the concentration at the emission source. In comparison to the examined "neutral air" upwind, the content of lung passing dust downwind has not been heightened significantly at any measuring point or time of the year, whereas the content of stable specific bacteria downwind was significantly higher up to a distance of 50 m (p < or = 0.01). The stable specific bacteria that were isolated from the air outside the pigsties, mostly gram positive cocci, had in part a strong resistance against Erythromycin, Penicillin, Tetracyclin and Ampicillin. The fact that in all investigated farms irritations or diseases of the animals respiratory tract in different degrees of intensity could be determined shows the urgency to minimize the burden by optimizing the hygienic situation inside the stalls. This means especially the colder period of the year, because a high frequency of transgression of the ammonia threshold value according to German regulations for pig housing could be found in this time.

Air↗
PubMed1994

Respiratory effects and tolerability of Mr 2264 Cl. A new opiate partial agonist in comparison with morphine and placebo.

In this double-blind, randomised, placebo-controlled cross-over study the respiratory effects of M(r) 2264 Cl 2 x 5 mg i.v., a new partial opiate receptor agonist, were investigated and compared with the respiratory effects of morphine 2 x 10 mg i.v. and placebo. As primary end-points, the slope of the rebreathing curve (dV'/dPCO2ET) and V55 (ventilation at PCO2ET = 55 mm Hg) were determined by Read's rebreathing method. The incidence of adverse events was also documented and compared. The respiratory depression after the intravenous administration of 5 mg and 10 mg M(r) 2264 Cl was comparable to the decreased sensitivity of the respiratory centre after the 20 mg morphine i.v. In contrast to morphine, a ceiling effect of M(r) 2264 Cl was found. The tolerability of M(r) 2264 Cl was comparable to that of morphine.

Adult↗
PubMed1993

The bacterial and mouse mammary tumor virus superantigens; two different families of proteins with the same functions.

In conclusion, the bacterial toxins are completely unlike the MTV superantigens in primary sequence and structure. The former are soluble globular proteins which do not have to be proteolytically cleaved before they act. The latter are synthesized as type II membrane proteins and may be clipped before they reach the cell surface and act to stimulate T cells. Table III summarizes the similarities and differences between the two sets of superantigens. The most notable quality of these molecules is that both sets of families have developed strategies whereby they bind to Class II and engage V beta. As far as the microorganisms which produce them are concerned, these two properties appear to be essential since they are absolutely conserved over proteins of a number of different structures. Several questions can now be addressed as follows. a. Why do all known superantigens bind to Class II? For the microorganism which produces them, the function of superantigens appears to be T-cell and perhaps directly or indirectly B-cell and macrophage stimulation. Activation of virgin T cells requires engagement with antigen plus MHC on professional antigen-presenting cells. Unlike other cell surface proteins, for example Class I, most Class II in animals is expressed on such cells. Therefore it is likely that superantigens have evolved to engage Class II because presentation to T cells by Class II-bearing cells offers the superantigen the best chance of activating its target T cells. b. Why do superantigens engage TCR V beta and not V alpha or CD3? It is possible that superantigens bind to the V beta portion of the TCR rather than V alpha because the latter does not have a consistently well exposed face for engagement. The fact that it is perhaps relatively easier to produce anti-V beta rather than anti-V alpha antibodies supports this idea. We have shown that N-glycosylation of V beta can interfere with recognition by vSAGs (Pullen et al. 1991), perhaps glycosylation of V alpha tends to conceal otherwise available sites. As far as C beta, C alpha or CD3 engagement is concerned, this may be just too dangerous for MTVs. The role of MTVs SAgs in the life history of the virus seems to be to stimulate T cells in the suckling recipient and thereby create a pool of activated lymphocytes in which the virus may survive until the mouse gives birth and transmits the virus to her own progeny (Hainaut et al. 1990, Golovkina et al. 1992).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Attitudes toward deafness. A collegiate perspective.

The Rochester Institute of Technology is a unique environment; a large number of hearing-impaired students are enrolled on a predominately hearing campus. The authors of this article explored the integration of deaf and hearing students on the campus and the attitudes surrounding deaf-hearing relationships. The major factors that hearing students identified as contributors to positive interaction between the two groups included awareness of cultural diversity, communication sensitivity and development of effective communication skills, structured opportunities for interaction, and mutual accommodation and respect.

Adolescent↗
PubMed1991

Limitations of flow detection by color Doppler: in vitro comparison to conventional Doppler.

There is little awareness of the limitations of flow detection with the commercially available color Doppler flow mapping system. The influence of flow velocity, ultrasound attenuation, and penetration depth on flow detection in color Doppler (Toshiba SSH 65A) were therefore studied in vitro and compared with conventional Doppler. The flow model had physiological flow volumes and laminar flow with parabolic velocity profile in a horizontal tube of Lucite with less than 3 degrees of coincidence. Conventional Doppler flow velocity measurements correlated highly with laser Doppler anemometry results (r = 0.99, SEE = 3 cm/sec). Signal strength of color Doppler and pulsed Doppler was semi-quantitatively graded using a scale from 0 to 5. Scale 1 (sparse signals) was useless for any assessment in color Doppler but just allowed velocity measurement in pulsed Doppler. Using 19-dB attenuation, flow velocities greater than 100 cm/sec had good scores with moderate gain, 60-100 cm/sec needed increasing gain, and velocities less than 40 cm/sec were not detectable with color Doppler but readily so with pulsed Doppler. With increasing attenuation (1-29 dB) and also with increasing penetration depth, flow detection was reduced significantly (P less than 0.001) more in color Doppler than in the pulsed technique (P less than 0.01). In conclusion, low flow velocities, high attenuation, and greater than 8 cm penetration depth may hamper flow detection in color Doppler and, thus, diagnostic accuracy. Conventional Doppler with its superior accuracy and sensitivity should therefore consolidate diagnostic ultrasound assessment.

Blood Flow Velocity↗
PubMed1991

[Vascularized porous synthetics as framework for preformed free flaps].

Porous plastic materials are being utilized more and more in plastic and reconstructive surgery. It appears to be possible to use these plastic materials as a frame, thus giving support and shape to free flaps. Compared with autologous materials such as bone and cartilage, porous plastic materials facilitate vascularization and tissue ingrowth and do not lead to the development of a surrounding capsule. In an experimental study involving 54 Wistar rats, three porous plastic materials were compared to silicone rubber. The analyses of material performance, microangiography, histological and histometrical observations are encouraging.

Animals↗
PubMed1990

[Echographic anatomy of the newborn hip and high-resolution equipment: internal capsular stria and perichondrial gap].

The use of high-resolution US equipment in the examination of the newborn hip allowed the evaluation of a thin echogenic stripe (the internal capsular stripe), which defines laterally the acetabular hyaline cartilage. By means of an anatomo-histological preparation the echogenic stripe can be related to either the capsular circular fibres or the interface between the latter and the hyaline cartilage. The internal capsular stripe, together with the echogenic synovial stripe, precisely delimit the whole acetabular hyaline cartilage. Furthermore, in many babies high-resolution US sometimes fails to demonstrate Graf's "perichondral gap", so that an accurate anatomic knowledge of the hip becomes necessary in the evaluation of acetabular labrum.

Hip Joint↗
PubMed1990

[Accuracy of various Doppler technics in recording blood flow velocity. Studies in vitro].

Conventional and color-coded Doppler techniques were studied as to their accuracy in displaying flow and velocity using an in vitro model and a Laser-Doppler-anemometer. Furthermore, the estimation of pressure gradients as determined by Doppler ultrasound was compared to measurements by manometers under a variety of hemodynamic conditions. Pulsed and continuous wave Doppler had good reproducibility. There was an excellent correlation for measurements of flow velocity as determined by Doppler ultrasound and by Laser-Doppler anemometer (r = 0.98, SEE = 3 cm/s). The well-known underestimation of flow velocity due to an increasing angle of incidence (greater than 25 degrees) was confirmed in vitro. However this error was smaller than the actual overestimation resulting from angle correction for the apparent cosine. Doppler gradients correlated strongly with manometer gradients for orifice areas 12-80 mm2 and flow volumes 0.9-12.8 l/min (r = 0.98, SEE = 7 mm Hg) using continuous as well as pulsatile flow. Some overestimation of the Doppler gradient occurred with increasing flow rates (r = 0.66). Color-Doppler has poor spatial resolution. Display of velocities was therefore assessed using a qualitative score (0-5), the variability of which was 13 +/- 30% of the initial value. Display of faintest quality (score 1) was useless for clinical assessment in color-Doppler technique, but allowed quantitative measurement of velocity in conventional Doppler. Reduction of flow velocities limited display in color-Doppler (5-20 cm/s) but not in pulsed-Doppler technique. Thus, conventional Doppler has better sensitivity and accuracy of displaying flow when compared to color-Doppler, particularly in conditions of poor imaging. As reproducibility and accuracy of velocity determination are excellent, this technique should be used in all diagnostic procedures involving ultrasound. The Doppler gradient as derived from the modified Bernoulli equation provides accurate results in vitro which may also be concluded for use in the clinical situation.

Blood Flow Velocity↗
PubMed1989

An analysis of 1,423 facial fractures in 788 patients at an urban trauma center.

The hospital records of all patients presenting to a large urban trauma center emergency department with facial fractures from 1980 through 1984 were reviewed retrospectively. There were 788 patients in the study group, averaging 1.8 fractures per patient for a total of 1,423 facial fractures. The study population had 638 (80.9%) males and 150 (19.1%) females. Racial mix was 71.6% black, 27.8% white, and 0.6% oriental. The most frequent fracture involved the zygoma (23.6%), followed by the orbital floor (21.4%), maxilla, mandible, and nasal bones. The most frequent etiology was assault with a blunt object or fist (70.1%) followed by motor vehicle accidents (13.5%), falls (9.3%), and gunshot wounds (6.1%). Initial diagnostic procedures included a facial X-ray series in 99.9%, tomograms in 43.1%, and CT studies in 8.1%. Surgical intervention was required in 61.2% of cases. Prosthetic materials were used in 8.5% of the cases. At our institution, personal assault was found to be the primary cause of both midface fractures and mandibular fractures.

Adult↗