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A Streit

Publications and source records attributed to A Streit.

35 records · Page 2Linked to original sources
PubMed1994

Isolation of a neural chondroitin sulfate proteoglycan with neurite outgrowth promoting properties.

Proteoglycans are expressed in various tissues on cell surfaces and in the extracellular matrix and display substantial heterogeneity of both protein and carbohydrate constituents. The functions of individual proteoglycans of the nervous system are not well characterized, partly because specific reagents which would permit their isolation are missing. We report here that the monoclonal antibody 473HD, which binds to the surface of early differentiation stages of murine astrocytes and oligodendrocytes, reacts with the chondroitin sulfate/dermatan sulfate hybrid epitope DSD-1 expressed on a central nervous system chondroitin sulfate proteoglycan designated DSD-1-PG. When purified from detergent-free postnatal days 7 to 14 mouse brain extracts, DSD-1-PG displays an apparent molecular mass between 800-1,000 kD with a prominent core glycoprotein of 350-400 kD. Polyclonal anti-DSD-1-PG antibodies and monoclonal antibody 473HD react with the same molecular species as shown by immunocytochemistry and sequential immunoprecipitation performed on postnatal mouse cerebellar cultures, suggesting that the DSD-1 epitope is restricted to one proteoglycan. DSD-1-PG promotes neurite outgrowth of embryonic day 14 mesencephalic and embryonic day 18 hippocampal neurons from rat, a process which can be blocked by monoclonal antibody 473HD and by enzymatic removal of the DSD-1-epitope. These results show that the hybrid glycosaminoglycan structure DSD-1 supports the morphological differentiation of central nervous system neurons.

Animals↗
PubMed1994

The effect of primary nursing job design dimensions on caregiving technology and job performance in nursing homes.

Primary nursing job design, ie permanent assignment and increased job autonomy and communication, has been suggested as especially appropriate for long-term care. The present study examined its effects on nursing home assistants' (N = 248) job performance and technology perceptions. Job design was found to have a significant effect on caregiving technology, even after controlling for individual differences. In particular, increased autonomy was significantly related to increased task variability which suggests that nursing assistants who have more job autonomy provide more customized care. Unexpectedly, increased duration of assignment was significantly related to increased homogeneity of tasks. Suggestions for future job design research in long-term care are made.

Attitude of Health Personnel↗
PubMed1994

The provision and use of mental health services in nursing homes: results from the National Medical Expenditure Survey.

Data from the Institutional Population Component of the National Medical Expenditure Survey were used to provide national estimates of annual mental health service provision and use in nursing homes. In addition, the relationship between service provision and setting characteristics such as ownership, size, Medicaid certification, and chain status was examined. Although more than three quarters of residents with a mental disorder resided at a nursing home that provided counseling services, fewer than one fifth actually received any mental health services within the year.

Counseling↗
PubMed1994

Determinants of the use of specialist mental health services by nursing home residents.

OBJECTIVE: This study examines the effects of resident and facility characteristics on the probability of nursing home residents receiving treatment by mental health professionals. DATA SOURCES/STUDY SETTING: The study uses data from the Institutional Population Component of the 1987 National Medical Expenditure Survey, a secondary data source containing data on 3,350 nursing home residents living in 810 nursing homes as of January 1, 1987. STUDY DESIGN: Andersen's health services use model (1968) is used to estimate a multivariate logistic equation for the effects of independent variables on the probability that a resident has received services from mental health professionals. Important variables include resident race, sex, and age; presence of several behaviors and reported mental illnesses; and facility ownership, facility size, and facility certification. DATA COLLECTION/EXTRACTION METHODS: Data on 188 residents were excluded from the sample because information was missing on several important variables. For some additional variables residents who had missing information were coded as negative responses. This left 3,162 observations for analysis in the logistic regressions. PRINCIPAL FINDINGS: Older residents and residents with more ADL limitations are much less likely than other residents to have received treatment from a mental health professional. Residents with reported depression, schizophrenia, or psychoses, and residents who are agitated or hallucinating are more likely to have received treatment. Residents in government nursing homes, homes run by chains, and homes with low levels of certification are less likely to have received treatment. CONCLUSIONS: Few residents receive treatment from mental health professionals despite need. Older, physically disabled residents need special attention. Care in certain types of facilities requires further study. New regulations mandating treatment for mentally ill residents will demand increased attention from nursing home administrators and mental health professionals.

Activities of Daily Living↗
PubMed1993

Variable effects of the conserved RNA hairpin element upon 3' end processing of histone pre-mRNA in vitro.

We have studied the requirements for efficient histone-specific RNA 3' processing in nuclear extract from mammalian tissue culture cells. Processing is strongly impaired by mutations in the pre-mRNA spacer element that reduce the base-pairing potential with U7 RNA. Moreover, by exchanging the hairpin and spacer elements of two differently processed H4 genes, we find that this difference is exclusively due to the spacer element. Finally, processing is inhibited by the addition of competitor RNAs, if these contain a wild-type spacer sequence, but not if their spacer element is mutated. Conversely, the importance of the hairpin for histone RNA 3' processing is highly variable: A hairpin mutant of the H4-12 gene is processed with almost wild-type efficiency in extract from K21 mouse mastocytoma cells but is strongly affected in HeLa cell extract, whereas an identical hairpin mutant of the H4-1 gene is affected in both extracts. The hairpin defect of H4-12-specific RNA in HeLa cells can be overcome by a compensatory mutation that increases the base complementarity to U7 snRNA. Very similar results were also obtained in RNA competition experiments: processing of H4-12-specific RNA can be competed by RNA carrying a wild-type hairpin element in extract from HeLa, but not K21 cells, whereas processing of H4-1-specific RNA can be competed in both extracts. With two additional histone genes we obtained results that were in one case intermediate and in the other similar to those obtained with H4-1. These results suggest that hairpin binding factor(s) can cooperatively support the ability of U7 snRNPs to form an active processing complex, but is(are) not directly involved in the processing mechanism.

Animals↗
PubMed1993

Mental health services for nursing home residents: what will it cost?

The Nursing Home Reform Act of 1987 requires nursing homes to provide basic mental health services for all residents and to give active mental health treatment, a set of specialized mental health services, to those residents who are admitted with a serious mental illness. This article examines the potential size of the nursing home population who will require mental health services, its demographic composition, and the facilities in which these individuals reside using the Institutional Population Component of the National Medical Expenditure Survey. Estimates of the potential costs of providing monthly psychotherapy and pharmacological management to this population in nursing homes indicate that the mandate will have significant financial effects on nursing facilities. Conclusions about how the requirements for maintaining the mental and psychosocial well-being of nursing home residents may affect the future of nursing home care and mental health care are considered.

Adolescent↗
PubMed1993

Interaction of astrochondrin with extracellular matrix components and its involvement in astrocyte process formation and cerebellar granule cell migration.

We have recently characterized a chondroitin sulfate proteoglycan from the murine central nervous system which is expressed by astrocytes in vitro and carries the L2/HNK-1 and L5 carbohydrate structures. In the present study, we provide evidence that its three core proteins of different size are similar in their proteolytic peptide maps and thus designate this group of structurally related molecules astrochondrin. During development, astrochondrin and the L5 carbohydrate were hardly detectable in the brain of 14-d-old mouse embryos by Western blot analysis. Expression of astrochondrin and the L5 epitope was highest at postnatal day 8, the peak of cerebellar granule cell migration and Bergmann glial process formation, and decreased to weakly detectable levels in the adult. Immunocytochemical localization of astrochondrin in the cerebellar cortex of 6-d-old mice showed association of immunoreactivity with the cell surface of astrocytes, including Bergmann glial processes and astrocytes in the internal granular layer or prospective white matter. Endfeet of astrocytes contacting the basal lamina of endothelial and meningeal cells and contact sites between Bergmann glial processes and granule cells also showed detectable levels of astrochondrin. Furthermore, granule cell axons in the molecular layer were astrochondrin immunoreactive. In the adult, astrochondrin immunoreactivity was weakly present in the internal granular layer and white matter. Both Fab fragments of polyclonal antibodies to astrochondrin and monovalent fragments of the L5 monoclonal antibody reduced the formation of processes of mature GFAP-positive astrocytes on laminin and collagen type IV, but not on fibronectin as substrata. Interestingly, the initial attachment of astrocytic cell bodies was not disturbed by these antibodies. Antibodies to astrochondrin also reduced the migration of granule cells in the early postnatal mouse cerebellar cortex. In a solid phase radioligand binding assay, astrochondrin was shown to bind to the extracellular matrix components laminin and collagen type IV, being enhanced in the presence of Ca2+, but not to fibronectin, J1/tenascin or other neural recognition molecules. Furthermore, astrochondrin interacted with collagen types III and V, less strongly with collagen types I, II, and IX, but not with collagen type VI. The interaction of astrochondrin with collagen types III and V was saturable and susceptible to increasing ionic strength, and could be competed by chondroitin sulfate, heparin, and dextran sulfate, but not by hyaluronic acid, glucose-6-phosphate, or neuraminic acid.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Biochemical demonstration of complex formation of histone pre-mRNA with U7 small nuclear ribonucleoprotein and hairpin binding factors.

Histone RNA 3' end formation occurs through a specific cleavage reaction that requires, among other things, base-pairing interactions between a conserved spacer element in the pre-mRNA and the minor U7 snRNA present as U7 snRNP. An oligonucleotide complementary to the first 16 nucleotides of U7 RNA can be used to characterize U7 snRNPs from nuclear extracts by native gel electrophoresis. Using similar native gel techniques, we present direct biochemical evidence for a stable association between histone pre-mRNA and U7 snRNPs. Other complexes formed in the nuclear extract are dependent on the 5' cap structure and on the conserved hairpin element of histone pre-mRNA, respectively. However, in contrast to the U7-specific complex, their formation is not required for processing. Comparison of several authentic and mutant histone pre-mRNAs with different spacer sequences demonstrates that the formation and stability of the U7-specific complex closely follows the predicted stability of the potential RNA-RNA hybrid. However, this does not exclude a stabilization of the complex by U7 snRNP structural proteins.

Animals↗
PubMed1992

The psychosocial quality of nursing home work.

Trained observers used components of the functional job analysis technique to categorize 3,371 tasks performed by 214 nursing assistants in four nursing homes on five occasions over 12 months. The extent to which each task was oriented toward residents versus data or things was coded along with the "level of complexity" of each of these orientations. A psychosocial index was created by multiplying orientation by complexity. Three questions structured the analyses: (a) To what extent do nursing assistants' tasks involve interacting with residents, as opposed to focusing on data or manipulating things? (b) How complex are these tasks? (c) What are the implications of the task analysis data for assessing the quality of psychosocial care? Findings reveal that even among the direct care tasks (69% of total), the orientation was not predominantly toward the resident. Functional complexity of the tasks observed was consistently low. Those task types with the greatest psychosocial quality were those performed least frequently and vice versa. Implications of these results for restructuring nursing assistants' work are discussed.

Data Collection↗
PubMed1991

The L5 epitope: an early marker for neural induction in the chick embryo and its involvement in inductive interactions.

The pattern of expression of the carbohydrate epitope L5 was studied during early development of the chick neuroepithelium. Immunoreactivity first appears during gastrulation, at mid-primitive streak stage, and persists until at least 3.5 days of development. The epitope is expressed on all the components of the developing nervous system, both central and peripheral. In immunoblots, the antibody recognises a major component of about Mr 500,000 and several more minor components of lower molecular mass. If a Hensen's node from a donor embryo is transplanted into the area opaca of a host embryo, L5 immunoreactivity appears in the epiblast surrounding the graft. If hybridoma cells secreting the antibody are grafted together with Hensen's node into a host chick embryo, the induction of a supernumerary nervous system is inhibited. We suggest that the L5 epitope is an early and general marker for neural induction and that it may be involved directly in inductive interactions.

Animals↗
PubMed1990

Structure of a mouse histone-encoding gene cluster.

In addition to a previously described histone (H)-encoding H4 gene [Meier et al., Nucleic Acids Res. 17 (1989) 795], the mouse genomic DNA clone 53 contains two H3 genes, one functional and one partially deleted H2A gene, and one H2B gene. Clone 53 overlaps for 3 kb with MH143, another previously isolated mouse H-encoding clone [Yang et al., J. Biol. Chem. 262 (1987) 17118-17125], thus defining a 32-kb region of mouse chromosome 13 with a total of seven H-encoding genes. We have determined the nucleotide sequences and transcription start points of two genes coding for the H2A.1 and H3.2 proteins.

Amino Acid Sequence↗
PubMed1990

Isolation and biochemical characterization of a neural proteoglycan expressing the L5 carbohydrate epitope.

The monoclonal L5 antibody reacts with an N-glycosidically linked carbohydrate structure which is present on the neural cell adhesion molecule L1, neural chondroitin sulfate proteoglycans, and other not yet identified glycosylated proteins. Using this antibody, we isolated and characterized proteoglycans from adult mouse brain and cultured astrocytes biosynthetically labeled with Na2 35SO4 and a 3H-amino acid mixture. Our data suggest that the L5 proteoglycans of both sources are identical in their biochemical properties. The apparent molecular mass of the L5 proteoglycan is approximately 500 kDa. Digestion of the iodinated L5 proteoglycan from mouse brain and of the [35S]methionine-labeled L5 proteoglycan from cultured astrocytes with proteinase-free chondroitinases ABC and AC revealed three major core proteins with apparent molecular masses of approximately 380, 360, and 260 kDa. These represent molecularly distinct protein cores.

Animals↗
PubMed1990

[Change in cardiovascular activation in learning and performance situations in children with learning disorders].

A method is demonstrated for observing and statistically testing changes in cardiovascular activity in single cases between two types of situations, in this case a playing situation and a learning situation. Using this method it could be shown an abasement of cardiovascular activity during a learning situation together with their mother or father--compared to a playing situation--for 20 hyperactive children with learning problems of an average age of 9.7 years. Together with this abasement in cardiovascular activity there was observed a deterioration in the parent-child-relation. In the singles cases however it could be observed an abasement or an increase in cardiovascular activity. When the--often punishing--parent was replaced by a person who built up a positive relation to the child, there could be observed either an increase or an abasement or no change in cardiovascular activity, the effect being replaiable. The results point up to a critical examination of actual therapeutic concepts for children with learning problems.

Achievement↗
PubMed1987

[Which studies are suitable for the diagnosis of recurrences in resectable breast carcinoma? A retrospective analysis of the OSAKO 06/74 adjuvant study].

113 patients with first relapse in the OSAKO 06/74 adjuvant chemotherapy trial for resectable breast cancer were investigated retrospectively. Based on history alone, 85% of the relapses could have been presumed. Physical examination alone was positive in 82% of relapses. Depending on the localization of relapse, the relative importance of different methods of examination differed. If history and physical examination were analyzed together, 96% of all relapses could be presumed. 45% of the patients did not see the doctor before the fixed time, although they suffered from symptoms associated with relapse. 26% of the women complained of symptoms during at least 4 months before diagnosis of relapse. We conclude that regular clinical controls, including careful history and scrupulous physical examination, represent the most efficient method for diagnosis of relapse in patients with resectable breast cancer.

Breast Neoplasms↗
PubMed1984

[Desamino-8-D-arginine vasopressin nose drops in the treatment of mild hemophilia A and von Willebrand's disease].

To permit home treatment in our patients we investigated the response to intranasal administration of 260 micrograms DDAVP in 28 patients with either mild hemophilia A or von Willebrand's disease. 6 patients with mild hemophilia A responded, and 6 did not. In the group with von Willebrand's disease 6 responded well, 4 responded partially and 6 did not respond. Knowledge of the severity of the disease did not allow us to predict the response, and therefore every patient should be tested individually. Intranasal DDAVP in our patients was used with success for bleeding into the knee joint, muscle hematoma and hematuria.

Arginine Vasopressin↗
PubMedDate not supplied

Origin of the vertebrate inner ear: evolution and induction of the otic placode.

The vertebrate inner ear forms a highly complex sensory structure responsible for the detection of sound and balance. Some new aspects on the evolutionary and developmental origin of the inner ear are summarised here. Recent molecular data have challenged the longstanding view that special sense organs such as the inner ear have evolved with the appearance of vertebrates. In addition, it has remained unclear whether the ear originally arose through a modification of the amphibian mechanosensory lateral line system or whether both evolved independently. A comparison of the developmental mechanisms giving rise to both sensory systems in different species should help to clarify some of these controversies. During embryonic development, the inner ear arises from a simple epithelium adjacent to the hindbrain, the otic placode, that is specified through inductive interactions with surrounding tissues. This review summarises the embryological evidence showing that the induction of the otic placode is a multistep process which requires sequential interaction of different tissues with the future otic ectoderm and the recent progress that has been made to identify some of the molecular players involved. Finally, the hypothesis is discussed that induction of all sensory placodes initially shares a common molecular pathway, which may have been responsible to generate an 'ancestral placode' during evolution.

Animals↗