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Biomedical subjects

C Simons

Publications and source records attributed to C Simons.

At least 19 recordsLinked to original sources

[Phases in the rehabilitation of male and female bone marrow transplant patients].

Teamwork is essential when investigating the long-term adoption of such medical intervention that are highly demanding on patients, physicians and nursing staff. Bone marrow transplantation represent such an intervention for a series of well defined hematological diseases. The contribution demonstrates the multiple perspective approach of the Ulm team. A case report illustrates the multiplicity of clinical issues. The state of research allows the sketching of a process model on rehabilitation.

Adaptation, Psychological

Immunochemical studies of the 36-kDa common beta subunit of guanine nucleotide-binding proteins: identification of a major epitope.

Twenty-four of 24 rabbits immunized with the beta subunit common to guanine nucleotide binding proteins developed antibodies reactive on immunoblots with the 15-kDa (amino-terminal) tryptic fragment of beta. Only 2 of 24 developed antibodies reactive with the 26-kDa (carboxy-terminal) tryptic fragment. The 15-kDa fragment-reactive antibodies were also detected in several nonimmune sera. Antibodies reactive with the 15-kDa fragment could be affinity-purified from all beta-immune sera by adsorption to a fusion protein encoded by a cDNA clone identified by expression vector screening. The 15-kDa fragment antibodies in nonimmune sera did not bind to the fusion protein. Limited amino acid sequence homology between the 36-kDa beta subunit and the protein encoded by the cDNA clone suggested that the amino-terminal decapeptide of beta contains a major epitope. A synthetic decapeptide, corresponding to the amino terminus of the 36-kDa beta subunit, effectively and specifically blocked binding of antibodies in beta-immune sera (but not in beta-reactive nonimmune sera) to nitrocellulose-bound 15-kDa fragment. The 15-kDa fragment-reactive antibodies could be affinity-purified from beta-immune sera on a matrix containing bound decapeptide; affinity-purified antibodies reacted equally well with the 36- and 35-kDa forms of the beta subunit. Native transducin beta/gamma complexes readily blocked binding of 15-kDa fragment-reactive antibodies in immune but not nonimmune sera from binding to the nitrocellulose-bound fragment. The results show that nonimmune sera may contain antibodies directed against an epitope of the 15-kDa fragment that is buried in the native beta/gamma complex. In contrast, the amino terminal decapeptide of the beta subunit is exposed on the surface of the native protein and contains a major antigenic site in both the 35- and 36-kDa forms.

Amino Acid Sequence

Differential distribution of signal-transducing G-proteins in retina.

We used specific antibodies in immunoblot studies of membrane fractions derived from bovine retina, and in immunohistochemical studies of sections of rat retina to determine the distribution of two guanine nucleotide binding proteins Go (a G-protein of unknown function discovered in the brain) and transducin, in retina. Both Go and transducin were readily detected in membranes derived from whole retina, and in crude rod outer segment membranes. Purification of rod outer segment membranes by sucrose density gradient centrifugation resulted in enrichment in transducin and depletion of Go immunoreactivity. Transducin-alpha immunoreactivity was localized to photoreceptor inner and outer segments and the outer nuclear layer. In contrast, Go-alpha immunoreactivity was localized in the inner and outer plexiform layers and ganglion cell layer. The results indicate that Go unlike transducin, is not associated with rod outer segment membranes and is therefore unlikely to function in phototransduction. Go is, however, relatively abundant in neural layers of retina where it may be involved in signal transduction.

Animals

Reduced expression of multiple forms of the alpha subunit of the stimulatory GTP-binding protein in pseudohypoparathyroidism type Ia.

We examined the expression of the alpha subunit of the stimulatory GTP-binding protein (Gs) in fibroblasts of subjects with pseudohypoparathyroidism (PHP) type Ia by transfer blot hybridization and S1 nuclease analyses. Six subjects with PHP type Ia showed decreased steady-state content of Gs alpha mRNA. S1 nuclease analysis indicates that both long and short forms of Gs alpha mRNA are decreased, with no apparent change in the ratio of long to short forms in PHP compared with normal individuals. It appears likely that in some cases of PHP type Ia the genetic lesion affects the maintenance of mRNA levels for all forms of the Gs alpha subunit.

DNA

Human cDNA clones for four species of G alpha s signal transduction protein.

lambda gt11 cDNA libraries derived from human brain were screened with oligonucleotide probes for recombinants that code for alpha subunits of G signal transduction proteins. Eleven alpha s clones were detected with both probes and characterized. Four types of alpha s cDNA were cloned that differ in nucleotide sequence in the region that corresponds to amino acid residues 71-88. The clones differ in the codon for alpha s amino acid residue 71 (glutamic acid or aspartic acid), the presence or absence of codons for the next 15 amino acid residues, and the presence or absence of an adjacent serine residue. S1 nuclease protection experiments revealed at least two forms of alpha s mRNA. A mechanism for generating four species of alpha s mRNA by alternative splicing of precursor RNA is proposed.

Amino Acid Sequence

Antisera against a guanine nucleotide binding protein from retina cross-react with the beta subunit of the adenylyl cyclase-associated guanine nucleotide binding proteins, Ns and Ni.

Antisera were produced in rabbits against a guanine nucleotide binding protein (N protein), transducin, purified from bovine retina. Antiserum AS/1, which recognized all three subunits (alpha, beta, and gamma) of the holoprotein, was tested for cross-reactivity with the subunits of the adenylyl cyclase [adenylate cyclase; ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1]-associated stimulatory (Ns) and inhibitory (Ni) N proteins purified from human erythrocytes. As/1 showed strong reactivity against the beta subunits of both Ns and Ni but failed to cross-react with either the alpha or gamma subunits of Ns and Ni. Seven additional antisera against transducin reacted with the beta subunits but not with the alpha or gamma subunits of Ns and Ni. A single antiserum against transducin reacted with the alpha subunit of Ni but not of Ns. Immunostaining of the beta subunits of Ns and Ni was proportional to the amount of beta subunit blotted and to the antiserum concentration. Immunostaining of either human erythrocyte or bovine cerebral cortical plasma membrane proteins with AS/1 showed a single band, comigrating with the beta subunit of transducin; this band was absent in bovine erythrocyte membranes. Estimation of the amount of beta subunit by immunoblotting with AS/1 showed that the beta subunit comprises approximately equal to 2% of bovine cerebral cortical plasma membrane protein, approximately equal to 100-fold more than in human erythrocyte membranes. These findings provide immunochemical evidence for similarities in the beta subunits and differences in the alpha and gamma subunits of this family of N proteins. Antisera against transducin react specifically with the beta subunits of Ns and Ni in crude plasma membranes and, thus, can serve as specific probes for the beta subunit.

Adenylyl Cyclases

Antibodies against a retinal guanine nucleotide-binding protein cross-react with a single plasma membrane protein in non-retinal tissues.

Antisera (AS/1-AS/6) to purified bovine retinal transducin, a guanine nucleotide-binding protein, were produced in 6 rabbits. Immunoblots showed that the antisera varied in their reactivity with the subunits of transducin; AS/1 reacted strongly with all 3 subunits, while the others reacted with only the beta and/or gamma subunits. Only AS/1 specifically immunoprecipitated the alpha subunit radiolabeled with non-covalently bound guanine nucleotides. Immunostaining of plasma membrane proteins from non-retinal tissues with AS-1 revealed a single protein (approx. 35 kDa), most likely representing the beta subunit of the guanine nucleotide-binding proteins (Gs and Gi) associated with adenylate cyclase. Cerebral cortex showed the highest content of this protein. Antisera against transducin provide a highly specific and sensitive probe for quantitation of the beta subunit of Gs and Gi.

Animals

Integration of the psychosomatic approach with internal medicine: development of concepts and preliminary results of evaluation of doctor-patient interaction.

An account is presented of an attempt (made in the period between 1972 and 1979) to integrate a psychosomatic approach in routine patient care in a medical hospital. Following disappointment with a service run on a consultation-liaison basis, patient care on a small general medical ward was reorganized systematically according to psychosomatic principles. Within this relatively independent subsystem of the hospital, it was possible to integrate the medical and the psychosomatic aspects into a single approach. The organizational concept for the ward is described; first results are reported of an attempt to evaluate the factual changes in doctor-patient communication during the daily ward round. This communication was studied in the form of verbal contacts between doctor and patient. Finally a summary is presented of the advantages of the integrated approach over the traditional consultation-liaison service.

Communication

[Psychic development of children under conditions of longterm isolation (author's transl)].

Three children with severe combined immunodeficiency have been isolated for 19-22 months. Two of the children have been placed into the isolation system directly after delivery; on child entered the isolation system at the age of 5 months. The influence of this situation on the psychic development of the children was studied by the means of direct observation as well as by psychometric test methods. An additional child which has been isolated between the age of 6 and 32 months was retested at the age of 4 and 6 years. The reported observation which include those of the parents and the team allow the conclusion, that a normal development is possible under these extreme conditions, when an optimal clinical and psychological support is maintained.

Child Development

Maternal attitudes to their obstetric care.

Advocates of 'natural childbirth' are many and vocal, but there appears also to be a group of women who are in favour of more active obstetric management. Preference for a subsequent confinement seems to be influenced by previous experience.

Anesthesia, Epidural