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Biomedical subjects

D Krause

Publications and source records attributed to D Krause.

At least 91 records · Page 5Linked to original sources
PubMed1995

Morphological study in the early stages of complement C5a fragment-induced experimental meningitis: activation of macrophages and astrocytes.

Subarachnoidal application of the complement C5a fragment was used to induce acute experimental meningitis in rabbits and rats within 30-60 min. The early stages of the cellular inflammatory response were studied by means of flow cytometry, transmission electron microscopy and immunofluorescence microscopy. Infiltration of polymorphonuclear leukocytes (PMN) into the subarachnoidal space was the earliest event of the inflammatory reaction. By morphological criteria we found that PMN interacted with cells of the mononuclear-macrophage lineage (MML) and the marginal astrocytes via pseudopodia, whereas the pial cells were not involved in early stages of the inflammatory response. The number of invaded MML that were positive with the ED2 marker increased, indicating the hematogenous origin of the immigrating cell population. PMN were found to infiltrate the perivascular space of the marginal arterial vessel segments. This perivascular infiltration was assumed to be the first manifestation of cerebral vasculitis. The intimate association of resident cerebral cells (astrocytes) with invading PMN and MML is suggestive of a transient interaction of these cell types.

Animals↗
PubMed1995

Immunolocalization of the neural cell adhesion molecule L1 in non-proliferating epithelial cells of the male urogenital tract.

The localization of the neural cell adhesion molecule L1 in the male urogenital tract (including seminal vesicles and prostate) of the mouse and bull was investigated using immunocytochemical and immunochemical methods in order to better understand the function of this glycoprotein in non-neural tissues. L1 antibodies labeled non-myelinated nerves in all portions of the urogenital tract investigated. However, L1 immunoreactivity was also found between epithelial cells of several regions of the urogenital system including epididymal tail, deferent duct, ejaculatory duct and seminal vesicles. Some L1 immunoreactivity was also demonstrated between epithelial cells of murine urinary bladder and urethra. The specificity of the immunoreaction was verified by western blots. There was no correlation between L1 expression and proliferating activity as revealed by double immunocytochemistry using various markers of cell proliferation. This unexpected expression of L1 in nonneural tissues is mainly restricted to non-proliferating epithelia of those portions of the urogenital tract that are derived from the Wolffian duct. It is suggested that L1 in these epithelia could enhance the mechanical resistance and reduce transepithelial permeability.

Animals↗
PubMed1995

Changes in the expression pattern of blood-brain barrier-associated pericytic aminopeptidase N (pAP N) in the course of acute experimental autoimmune encephalomyelitis.

The role of cerebral pericytes in blood-brain barrier (BBB) mechanisms is still a matter of controversy. Because acute experimental autoimmune encephalomyelitis (EAE) is characterized by a transient and focal perturbation of the BBB, we have utilized the model of adoptive transfer EAE to correlate the expression of the pericytic aminopeptidase N (pAP N) with the acute functional state of the BBB. We demonstrate that a significant downregulation of microvascular pAP N expression occurs, and the observed perturbation of the enzymatic BBB complement seems to be a sustained effect which persists even after recovery from clinical disease. At the peak of clinical disease, numerous pAP N expressing invasive cells were detected in white matter of the lumbar spinal cord. Through the use of a panel of different immunocytochemical markers these pAP N-immunopositive cells were characterized as ED 1-positive, most likely hematogenous macrophages. Activated resident microglial cells participate in the EAE-induced inflammatory process to only a minor extent.

Acute Disease↗
PubMed1995

Immunogenicity of an inactivated hepatitis A vaccine in Alaska Native children and Native and non-Native adults.

The response to an inactivated hepatitis A vaccine was assessed in 307 persons: 163 Alaska Native children, ages 3-6 years, and 144 Native (84) and non-Native (60) adults. All adults received the same vaccine schedule (0, 1, and 12 months), whereas children were randomized to receive three different schedules (0, 1, and 6; 0, 1, and 2; or 0, 1, and 12 months). After one dose, 141 (96%) of 147 children and 129 (90%) of 143 adults responded with levels of antibody to hepatitis A virus > 20 mIU/mL. After three doses, all participants responded. The geometric mean titer (GMT) 1 month after the third dose was significantly higher in children who received the third dose 12 months after the first dose rather than 2 months after the first dose. While there were differences in the GMT of some blood samples by age, sex, and ethnicity, all participants responded to the vaccine.

Adolescent↗
PubMed1995

[Surgical results of pertrochanteric fractures. A 15-year study].

During the last 15 years new methods for the surgical treatment of pertrochanteric fractures have been developed [e.g. the dynamic hip screw (DHS) and the gamma-nail (GN)]. We report on the results obtained in 450 patients operated on between 1979 and 1984 (period I), from 1986 to 1989 (period II), and between 1991 and 1993 (period III); we reviewed the results with the intension of finding whether application of the new methods led to better results, shorter stay in hospital and fewer complications. The mean age of all patients was 79 years and was 4 years higher in period I to than in period III (77.5 +/- 9.2 vs 81.5 +/- 8.4). During period I, 65% of the fractures were stabilized using Ender rods, while during period III the DHS was used in nearly 60% and the GN, in 22%. The total hospital stay (department of surgery and geriatric hospital) decreased from 80.4 +/- 31.7 in period I to 66.6 +/- 24 days in period III (P < 0.001). Serious complications decreased by 80% during this time. During period I 86.2% of patients could be discharged home, as against 89.0% in period II and 94.7% during period III. The introduction of new operative techniques for the treatment of pertrochanteric fractures in the elderly was followed by a dramatic shortening of hospital stay, a reduced incidence of complications, early weight-bearing and an increased rate of discharge home.

Aged↗
PubMed1995

A semantic network model for the medical record of a rheumatology clinic.

For the development of a rheumatology information system, a medical data dictionary was developed that supports all phases of software development. In the design phase, the medical expert described his clinical environment and the rheumatology medical record in a semantic network structure. Causal relationships between different items of the medical record (e.g., a problem may be related to an adverse drug event caused by a particular drug) are also represented in the semantic network and transferred into referential integrity constraints of the patient database. Furthermore, by also integrating the domain management as a feature of the medical data dictionary, the elementary attributes of the medical record and the associated lists of valid attribute entries have also been defined within the semantic network. This structure allowed the automatic generation of data entry screens, thus making the clinical applications as independent from any hardcoded program module as possible.

Algorithms↗
PubMed1995

[Current aspects of secondary and tertiary prevention from the viewpoint of the clinical gerontologist].

Prevention is of importance when the patient is already suffering from a serious disease, e.g., from arterial obstructive disease causing a stroke or an amputation, from a hip fracture or other diseases that might threaten his independence. Prevention covers a wide field of topics. Most importantly, the patient must recover from his acute disease. It is important to avoid complications which are not specific for the disease but are typical for a bedridden old person (decubital ulcer, dehydration etc.). Prevention also means to avoid recurrence of the same disease as well as complications that frequently occur during the clinical course and may influence the outcome (spasticity in stroke patients, muscular calcification following hip replacement).

Activities of Daily Living↗
PubMed1995

[Surgical results of per- and subtrochanteric femoral fractures. An overview of 15 years].

During the last 15 years, new methods for the surgical approach to pertrochanteric and subtrochanteric fractures were developed (eg. the dynamic hip screw (DHS) and the gamma-nail (GN)). Reviewing the results of this change in methods, we report on 450 patients with pertrochanteric fractures and 102 patients after subtrochanteric fractures of the femur. According to different surgical techniques, the patients were allocated into three periods (1980-1984, period I: 1986-1989, period II; 1991-1993, period III). During period I. 65% of the pertrochanteric fractures were stabilized using Ender-rods, during period III nearly 60% were operated using the DHS and 22% using the gamma-nail. The total hospital stay (department of surgery as well as the geriatric hospital) decreased from 80.4 +/- 31.7 days to 66.6 +/- 24 days (p < 0.001). Serious complications decreased by 80% during this time. During period I, 86.2% of patients with pertrochanteric fractures could be discharged at home, but in 89% in period II and 94.7% during period III. During period I, 74% of the subtrochanteric fractures were stabilized using an angle plate. During period III, more than 30% were operated by using the DHS and nearly 50% by using the gamma-nail. The total hospital stay (department of surgery as well as the geriatric hospital) decreased from 107.5 +/- 46.5 to 78.9 +/- 24.3 days (p < 0.001). During period I, 86.2% of patients with subtrochanteric fractures could be discharged at home, but 100% during period III. Serious complication as well as discharges to nursing home decreased during these 15 years.

Aged↗
PubMed1994

Expression of the tight junction protein ZO-1 in the olfactory system: presence of ZO-1 on olfactory sensory neurons and glial cells.

The olfactory system is a unique part of the central nervous system since it retains neuronal turnover and regenerative capacities in adulthood. Thus it provides an ideal model to study plasticity of membrane moities involved in cell-cell interactions. One structure particularly involved in cell-cell interaction is the tight junction, which establishes polarization of epithelial cells and creates diffusion barriers to paracellular passages. ZO-1 is a phosphoprotein peripherally associated with tight junctions. We have studied expression of ZO-1 protein in the developing and adult olfactory system of the mouse in order to get information about the localization and developmental expression of this tight junction component. ZO-1 expression has also been determined in cell cultures of olfactory bulbs. ZO-1 was present in the olfactory placode prior to formation of tight junctions. ZO-1 was localized in the developing and mature olfactory epithelium at heterotypic contacts between supporting cells and olfactory neurons as well as at homotypic contacts between both these cell types. Confocal microscopy showed quantitative differences in the ZO-1 expression among different olfactory dendrites. In the olfactory nerves ZO-1 immunolabeling was detectable between olfactory ensheathing cells. From the seventh postnatal day ZO-1 immunolabeling was detected at the mitral cell layer of the bulb on cells tentatively identified as oligodendrocytes. Myelinated tracts of the bulb were ZO-1 negative. Cell cultures of olfactory bulbs showed ZO-1 immunoreaction, mostly localized on glial fibrillary acidic protein (GFAP)-positive cells. Our results provide further evidence that ZO-1 serves functions unrelated to the tight junction complex and indicate molecular heterogeneity of these cell-cell contacts.

Animals↗
PubMed1994

Temporally incoherent magnetic fields mitigate the response of biological systems to temporally coherent magnetic fields.

We have previously demonstrated that a weak, extremely-low-frequency magnetic field must be coherent for some minimum length of time (approximately 10 s) in order to affect the specific activity of ornithine decarboxylase (ODC) in L929 mouse cells. In this study we explore whether or not the superposition of an incoherent (noise) magnetic field can block the bioeffect of a coherent 60 Hz magnetic field, since the sum of the two fields is incoherent. An experimental test of this idea was conducted using as a biological marker the twofold enhancement of ODC activity found in L929 murine cells after exposure to a 60 Hz, 10 microT rms magnetic field. We superimposed an incoherent magnetic noise field, containing frequencies from 30 to 90 Hz, whose rms amplitude was comparable to that of the 60 Hz field. Under these conditions the ODC activity observed after exposure was equal to control levels. It is concluded that the superposition of incoherent magnetic fields can block the enhancement of ODC activity by a coherent magnetic field if the strength of the incoherent field is equal to or greater than that of the coherent field. When the superimposed, incoherent noise field was reduced in strength, the enhancement of ODC activity by the coherent field increased. Full ODC enhancement was obtained when the rms value of the applied EM noise was less than one-tenth that of the coherent field. These results are discussed in relation to the question of cellular detection of weak EM fields in the presence of endogenous thermal noise fields.

Animals↗
PubMed1994

[Association of infectious aneurysm and microbial spondylodiscitis: physiopathological hypotheses, diagnostic and therapeutic approach].

Two years after a Staphylococcus aureus septicaemia, in a patient with dermatopolymyositis occurred an infectious aneurysm of abdominal aorta with contiguous pyogenic spondylodiscitis. Coexistence of both pathologies is rare and physiopathological mechanisms still remain uncertain. However, many arguments in the present case report are in favour of the initial responsibility of an infectious aneurysm. Main interest in early diagnosing infectious aneurysm, allowed by new investigations such as magnetic resonance imaging and marked leukocyte bone scanning, is the prevention of major complications. Antibiotherapy and surgical removal of infectious aneurysm must be quickly achieved in every case.

Aneurysm, Infected↗
PubMed1994

The 140-kDa protein of blood-brain barrier-associated pericytes is identical to aminopeptidase N.

Although ample evidence has been accumulated on the structure and functional role of endothelial cells in blood-brain barrier mechanisms, little is known about the contribution that cerebral pericytes provide to this phenomenon. We have reported recently on a monoclonal antibody specific for cerebral pericytes at blood-brain barrier sites. To confirm the pericytic localization of this antigen, and in order to elucidate its biochemical identity, we have performed immunocytochemical, biochemical, and molecular biological studies. By immunocytochemistry on the light microscopic as well as electron microscopic level, we provide definite evidence that the 140-kDa antigen recognized by this monoclonal antibody is confined to cerebral pericytes, whereas endothelial cells are devoid of this antigen. N-Terminal sequencing of the corresponding immunocrossreacting renal protein revealed that the protein detected by the monoclonal antibody is identical to aminopeptidase N. By means of the reverse transcriptase-polymerase chain reaction, the identity of the 140-kDa antigen as aminopeptidase N could also be verified for cerebral microvascular cells. Cerebral pericytic aminopeptidase N may be involved in neurotransmitter (enkephalin) metabolism at the blood-brain interface. By taking into account that brain pericytes have been found to express further plasma membrane-bound enzymes, these results strongly suggest the contribution of cerebral pericytes in the metabolic concert of the homeostatic balance regulated by the blood-brain barrier.

Amino Acid Sequence↗
PubMed1994

Comparative study of the immunogenicity and safety of two dosing schedules of Engerix-B hepatitis B vaccine in neonates.

A randomized multicenter study compared the routine hepatitis B vaccine schedule of 0, 1, 6 months with an accelerated schedule of 0, 1, 2 months in newborns. Two hundred ninety-nine infants whose mothers were seronegative for hepatitis B were enrolled in the study and randomized to either the routine or accelerated schedule. All infants had blood drawn for antibody titers to hepatitis B at 2, 3, 6 and 7 months of age. For 222 infants data were evaluable, at least for safety; 193 of these 22 had antibody titers that were evaluable. The infants vaccinated on the accelerated schedule developed seroprotective concentrations of antibody more quickly than the infants vaccinated on the routine schedule; 92.6% vs. 66.1% had seroprotective concentrations (> or = 10 mIU/ml) at 3 months of age (P < 0.001). However, infants in the accelerated schedule had lower geometric mean antibody titers at 7 months, 420.0 vs. 3141.8. We conclude that the accelerated vaccination schedule resulted in the more rapid development of seroprotective concentrations of antibody, but levels of antibodies were not as high as in the routinely vaccinated infants at 7 months. These data suggest that an accelerated vaccine schedule can be used in the newborn period. The effectiveness of the accelerated schedule in preventing perinatal infections compared to the standard schedule and the necessity for booster doses of vaccine remain to be studied.

Drug Administration Schedule↗