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Biomedical subjects

W M Fischer

Publications and source records attributed to W M Fischer.

At least 19 recordsLinked to original sources
PubMed2000

Molecular evidence for the early evolution of photosynthesis.

The origin and evolution of photosynthesis have long remained enigmatic due to a lack of sequence information of photosynthesis genes across the entire photosynthetic domain. To probe early evolutionary history of photosynthesis, we obtained new sequence information of a number of photosynthesis genes from the green sulfur bacterium Chlorobium tepidum and the green nonsulfur bacterium Chloroflexus aurantiacus. A total of 31 open reading frames that encode enzymes involved in bacteriochlorophyll/porphyrin biosynthesis, carotenoid biosynthesis, and photosynthetic electron transfer were identified in about 100 kilobase pairs of genomic sequence. Phylogenetic analyses of multiple magnesium-tetrapyrrole biosynthesis genes using a combination of distance, maximum parsimony, and maximum likelihood methods indicate that heliobacteria are closest to the last common ancestor of all oxygenic photosynthetic lineages and that green sulfur bacteria and green nonsulfur bacteria are each other's closest relatives. Parsimony and distance analyses further identify purple bacteria as the earliest emerging photosynthetic lineage. These results challenge previous conclusions based on 16S ribosomal RNA and Hsp60/Hsp70 analyses that green nonsulfur bacteria or heliobacteria are the earliest phototrophs. The overall consensus of our phylogenetic analysis, that bacteriochlorophyll biosynthesis evolved before chlorophyll biosynthesis, also argues against the long-held Granick hypothesis.

Bacteria↗
PubMed1999

Changes in clinic vaccination coverage after institution of measurement and feedback in 4 states and 2 cities.

BACKGROUND: Since 1995, states and jurisdictions receiving federal immunization funds have been required to perform annual measurements of vaccination coverage in their public clinics, based on data from Georgia where clinic coverage increased after the institution of a measurement and feedback intervention. OBJECTIVE: To determine if clinic vaccination coverage improved in localities that used the Georgia intervention model. DESIGN: Retrospective examination of clinic vaccination coverage data. PARTICIPANTS: Children aged 19 to 35 months enrolled in clinics in localities that had applied the intervention for 4 years or longer. INTERVENTION: The Georgia intervention model: assessment of clinic vaccination coverage, feedback of the information to the clinic, incentives to clinics, and promotion of exchange of information among clinics (AFIX). MAIN OUTCOME MEASURE: Change in median clinic coverage rates, based on the primary (4-3-1) vaccine series, with comparison to results of the National Immunization Survey. RESULTS: Four states and 2 cities that had applied the AFIX intervention for 4 years or longer were identified. The number of clinic records reviewed annually was 4639 to 18000 in 73 to 116 clinics for states, and 714 to 5276 in 8 to 25 clinics for cities. Median clinic coverage rose in all localities: Missouri, 44% (1992) to 93% (1997); Louisiana, 61% (1992) to 83% (1997); Colorado, 55% (1993) to 75% (1997); Iowa, 71% (1994) to 89% (1997); Boston, Mass, 41% (1994) to 79% (1997); and Houston, Tex, 28% (1994) to 84% (1997). The increase in clinic coverage exceeded that of the general population in 5 localities and was identical in the sixth. The average annual coverage rise attributable to the intervention was +5 percentage points per year (Georgia, +6 per year). The average crude direct program cost was $49533 per locality per year. CONCLUSION: The Georgia intervention model (AFIX) can be reproduced elsewhere and is associated with improvements in clinic vaccination coverage.

Child, Preschool↗
PubMed1992

GenBank.

The GenBank nucleotide sequence database now contains sequence data and associated annotation corresponding to 85,000,000 nucleotides in 67,000 entries from a total of 3,000 organisms. The input stream of data coming into the database is primarily as direct submissions from the scientific community on electronic media, with little or no data being keyboarded from the printed page by the databank staff. The data are maintained in a relational database management system and are made available in flatfile form through on-line access, and through various network and off-line computer-readable media. The data are also distributed in relational form through satellite copies at a number of institutions in the U.S. and elsewhere. In addition, GenBank provides the U.S. distribution center for the BIOSCI electronic bulletin board service.

Animals↗
PubMed1991

Fc receptor blocking antibodies after active immunization for the treatment of recurrent spontaneous abortion.

In a prospective study 140 couples who had at least three spontaneous abortions (RSA) were studied for the presence of Fc receptor blocking antibodies detected by the erythrocyte antibody rosette inhibition (EAI) assay, for anti-paternal cytotoxic antibodies (APCA), and for mixed lymphocyte culture inhibiting (MLCI) antibodies before and after active immunization with paternal lymphocytes. The comparative analysis revealed the EAI assay to possess a higher sensitivity than the APCA and/or MLCI tests in monitoring the specific immune response after active immunization. The success of pregnancy in EAI positive post-immunization patients was not influenced by the presence or absence of APCA or MLCI. In the light of a successful pregnancy outcome of 85.7% (n = 37) in this study we conclude that the monitoring of Fc receptor blocking antibodies is useful in active immunization protocols for RSA patients.

Abortion, Habitual↗
PubMed1990

Further characterization of the EAI factor induced by alloimmunization for treatment of recurrent abortion.

In order to remove the EAI "blocking" activity, EA inhibition positive sera from patients with recurrent abortions were absorbed after alloimmunization with paternal lymphocytes by the lymphoblastoid cell line (LCL) of the husband. To avoid non-specific binding via the Fc-receptor, the cells were first fixed with 0.05% glutaraldehyde. Absorption was performed for 3 h at 4 degrees C. For subsequent elution, the cells were incubated with 0.1 M glycine-HCl, pH 2.3, for 30 min at 4 degrees C. After each step, EAI assay was carried out to determine the "blocking" activity in the supernatants. Furthermore, 10% SDS-PAGE and immunoblotting with goat antihuman IgG of the whole serum and the supernatants were performed. The results obtained give evidence that the EAI "blocking" activity can be absorbed by and eluted from the LCL of the immunizing husband, and is due to an IgG antibody directed against an antigen present on the LCL. Further absorption experiments with trophoblast cells will show whether this antigen is also displayed by the trophoblast.

Abortion, Habitual↗
PubMed1979

A concept for stereological investigation of rat kidney.

An attempt is presented to adapt sampling procedures for stereological investigation of rat kidney. The proposed experimental design considers the zonal construction, in particular the structural and osmotic features of this organ. Every zone is treated as an own entity inregard to sample collection. In order to uncover possibly existing preferential orientation of structures the application of two mutually perpendicular section planes is recommended. Furthermore a method is described to determine absolute volumes and surface of structural components.

Animals↗