Fishing in the Amazonian forest: a gendered social network puzzle.

We employ social network analysis (SNA) to describe the structure of subsistence fishing social networks and to explore the relation between fishers' emic perceptions of fishing expertise and their position in networks. Participant observation and quantitative methods were employed among the Tsimane' Amerindians of the Bolivian Amazonia. A multiple regression quadratic assignment procedure was used to explore the extent to which gender, kinship, and age homophilies influence the formation of fishing networks. Logistic regressions were performed to determine the association between the fishers' expertise, their socio-demographic identities, and network centrality. We found that fishing networks are gendered and that there is a positive association between fishers' expertise and centrality in networks, an association that is more striking for women than for men. We propose that a social network perspective broadens understanding of the relations that shape the intracultural distribution of fishing expertise as well as natural resource access and use.

Alternative splicing regulates the nuclear or cytoplasmic localization of dystrophin Dp71.

The subcellular distribution of Dp71 isoforms alternatively spliced for exon 71 and/or 78 was examined. The cDNA sequence of each variant was fused to the C-terminus of the green fluorescent protein and the constructs were transfected transiently in the cell lines HeLa, C2C12 and N1E-115. The subcellular distribution of the fused proteins was determined by confocal microscope analysis. The Dp71 isoform lacking the amino acids encoded by exons 71 and 78 was found exclusively in the cytoplasm whereas the variants containing the amino acids encoded by exon 71 and/or exon 78 show a predominant nuclear localization. The nuclear localization of Dp71 provides a new clue towards the establishment of its cellular function.

Expression and synthesis of alternatively spliced variants of Dp71 in adult human brain.

Transcripts encoding the 70-75 kDa C-terminal protein product of the dystrophin gene (Dp71) are alternatively spliced to generate multiple protein products in a number of adult human tissues. In this report, reverse transcriptase-polymerase chain reaction was used to clone and characterize a subpopulation of truncated Dp71 transcripts in adult human brain tissue which did not contain exons 71-74, resulting in an in-frame deletion of 330 bp encoding the syntrophin-binding domain. These truncated Dp71 transcripts are also alternatively spliced for exon 78. Immunoblot analysis, using dystrophin-specific C-terminal antibodies directed against epitopes in either exon 77 (MANDRA1), or 78 (1461), identified full-length dystrophin, Dp140 and Dp71, in total protein lysates from adult human brain tissue. In addition, a minor immunoreactive protein of approximately 58 kDa was also identified (designated Dp71 big up tri, open(110)). The observation that a monoclonal antibody directed against epitopes within exons 73-74 (MANEX7374A) failed to detect this 58 kDa protein provides definitive evidence that Dp71 big up tri, open(110) is derived from Dp71 transcripts deleted for the syntrophin-binding domain. These results, as well as previous findings, demonstrate that alternative splicing of Dp71 in the human brain generates a variety of mRNA transcripts encoding distinct protein variants of Dp71, and further supports the use of exon-specific antibodies in characterizing these variants. The presence of these Dp71 protein variants in brain tissue points to their interaction with various cellular proteins and their involvement in different cellular functions.

Effects of dystrophin isoforms on signal transduction through neural retina: genotype-phenotype analysis of duchenne muscular dystrophy mouse mutants.

Duchenne and Becker muscular dystrophy patients have mutations in the dystrophin gene. Most show reduced b-wave amplitudes in the dark-adapted electroretinogram (ERG). We studied normal C57BL/6J mice and five X-linked muscular dystrophy strains with different dystrophin mutations to determine whether the location of the mutation within the gene affects the mouse ERG and to correlate such effects with dystrophin isoform expression. Amplitudes and implicit times were measured for a-waves, b-waves, and digitally filtered oscillatory potentials. mdx and mdxCv5 mice, with mutations near the amino terminus and lacking expression of Dp427, had ERGs similar to those of C57BL/6J mice. mdxCv2 and mdxCv4 mice, with mutations in the center of dystrophin and who do not express isoforms Dp427, Dp260, or Dp140 (mdxCv4), had increased b-wave and oscillatory potential implicit times. mdxCv3 mice, with a mutation near the carboxy terminus resulting in deficiency of all dystrophin isoforms, had increased b-wave and oscillatory potential implicit times and reduced scotopic b-wave amplitudes. Fitting the a-wave data to a transduction activation phase mathematical model showed normal responses for all phenotypes, suggesting that the b-wave delays are due to defects beyond the rod outer segment, most likely at the rod to on-bipolar cell synapse. The variation in the ERG phenotype with the position of the dystrophin gene mutation suggests that there are different contributions by each isoform to retinal electrophysiology. Although Dp427 and Dp140 isoforms do not appear to be important contributors to the ERG, lack of Dp260 and possibly Dp71 isoforms is associated with an abnormal ERG.

Dystrophin isoforms DP71 and DP427 have distinct roles in myogenic cells.

Duchenne muscular dystrophy is caused by mutations in the dystrophin gene, a complex gene that generates a family of distinct isoforms. In immature muscle cells, two dystrophin isoforms are expressed, Dp427 and Dp71. To characterize the function of Dp71 in myogenesis, we have examined the expression of Dp71 in myogenic cells. The localization of Dp71 in these cells is distinct from the localization of Dp427. Whereas Dp427 localizes to focal adhesions and surface membrane during myogenesis, Dp71 localizes to stress fiberlike structures in myogenic cells. Biochemical fractionation of myogenic cells demonstrates that Dp71 cosediments with the actin bundles thus confirming this interaction. Furthermore, transfection of C2C12 myoblasts with constructs encoding Dp71 fused to green fluorescent protein targeted the protein to the actin microfilament bundles. These results demonstrate involvement of Dp71 with the actin cytoskeleton during myogenesis and suggest a role for Dp71 that is distinct from Dp427.

Localization of dystrophin isoform Dp71 to the inner limiting membrane of the retina suggests a unique functional contribution of Dp71 in the retina.

The electroretinograms (ERGs) of patients with Duchenne muscular dystrophy and an allelic variant of the mdx mouse (mdxCv3) have been shown to be abnormal. Analysis of five allelic variants of the mdx mouse with mutations in the dystrophin gene has shown that there is a correlation between the position of the mutation and the severity of the ERG abnormality. Three isoforms are expressed in the retina: Dp427, Dp260 and Dp71. Using indirect immunofluorescence and isoform-specific antibodies on retinal sections from three allelic mdx mouse strains, we have examined the localization of each of the isoforms. We show that Dp71 expression does not overlap with Dp427 and Dp260 expression at the outer plexiform layer (OPL). Instead, Dp71 is localized to the inner limiting membrane (ILM) and to retinal blood vessels. Moreover, we show that Dp260 and Dp71 differ structurally at their respective C-termini. In addition, we find that the proper localization of the beta-dystroglycan is dependent upon both Dp260 at the OPL and Dp71 expression at the ILM. Thus, Dp260 and Dp71 are non-redundant isoforms that are located at different sites within the retina yet have a common interaction with beta-dystroglycan. Our data suggest that both Dp71 and Dp260 contribute distinct but essential roles to retinal electrophysiology.

Identification of a novel actin binding site within the Dp71 dystrophin isoform.

The Dp71 dystrophin isoform has recently been shown to localize to actin filament bundles in early myogenesis. We have identified an actin binding motif within Dp71 that is not found in other dystrophin isoforms. Actin overlay assays and transfection of COS-7 cells with fusion proteins of wild type and mutated Flag epitope-tagged Dp71 demonstrate that this motif is necessary and sufficient to direct localization of Dp71 to actin stress fibers. Furthermore, this localization is independent of alternative splicing which alters the C-terminus of the protein. The identification of an actin binding site suggests Dp71 may function to anchor membrane receptors to the cytoskeleton.

Cloning and characterization of alternatively spliced isoforms of Dp71.

Dp71, a C-terminal isoform of dystrophin, has been identified as the major DMD gene product in many nonmuscle tissues. In this report, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to clone and characterize four alternatively spliced Dp71 transcripts from cultured human amniocytes. The cDNAs encoding these Dp71 transcripts were shown to be alternatively spliced for exons 71 and/or 78. RT-PCR analysis also revealed that Dp71 transcripts alternatively spliced for exons 71 and/or 78 were expressed at varying levels in a number of adult human tissues, including muscle, heart, brain, kidney, lung, testis and liver. To investigate size heterogeneity at the translational level, Dp71 cDNAs isolated from amniocytes were expressed in E.coli to generate recombinant Dp71 fusion proteins. These fusion proteins were identified on immunoblots using antibodies specific for the C-terminal sequences of dystrophin that either included (antibody 1461) or excluded exon 78 (antibody 462B). The molecular masses of the Dp71 fusion proteins ranged from 71-75 kDa on SDS-PAGE, consistent with their predicted values. Immunoblot analysis using antibodies 1461 and 462B identified multiple Dp71 isoforms of approximately 70-75 kDa on SDS-PAGE in total protein lysates from amniocytes and various adult human tissues. This variation in molecular mass is consistent with the expression of Dp71 isoforms derived from transcripts alternatively spliced for exons 71 and/or 78. Total protein lysates from normal skeletal muscle, DMD muscle, amniocytes and brain were shown to contain beta-dystroglycan, a component of the dystrophin-associated glycoprotein complex (DGC).(ABSTRACT TRUNCATED AT 250 WORDS)

Patterns of autologous blood use in elective orthopedic surgery: does the availability of autologous blood change transfusion behavior?

We studied the orthopedic surgery service at our institution to determine whether the mere availability of autologous blood (AB) affected transfusion practice. As a group, patients who had AB available received an average of 1.11 fewer red cell units per hospitalization than did patients with only homologous blood (HB) available. At every transfusion episode, those patients having AB available received fewer red cell units than did patients without AB available. Predeposit of autologous red cells was effective in protecting 77.6% of patients from HB exposure. The availability of autologous red cells resulted in an overall more conservative approach to transfusion.

Polymerase chain reaction and allele-specific oligonucleotides in paternity testing of the deceased.

The assignment of paternity when the alleged father has died is now possible by use of a variety of allele-specific oligonucleotides after amplification of genomic DNA by the polymerase chain reaction (PCR). Issues relating to the inheritance of estates may be decided on fact rather than allegation. PCR-based genotyping of DQ alpha haplotypes from paraffin-embedded tissue of the deceased was used to prove non-paternity in the case reported here. Because the child was female, it was also possible to confirm the exclusion by using a second polymorphic site located in the factor VIII gene on the X chromosome.

Postthaw stability of fibrinogen in cryoprecipitate stored between 1 and 6 degrees C.

The fibrinogen activity in thawed cryoprecipitate stored between 1 and 6 degrees C is maintained essentially unchanged in most bags for a month. Occasionally, a bag will have a reduction in fibrinogen. If pooling has not occurred, thawed cryoprecipitate should be useful as a source of fibrinogen for a period of time considerably in excess of the 6 hours allowed for its use as a source of factor VIII or von Willebrand factor.

Amplification of the c-erb B-2 oncogene and prognosis of breast adenocarcinoma.

Fifty patients with typical infiltrating ductal adenocarcinoma of the breast were studied for amplification of the c-erb B-2 (neu/HER-2) oncogene within the tumor DNA. Amplification, ranging from 4 to greater than 50 copies per cell, was observed in 17 (34%) of the samples. The presence of c-erb B-2 gene amplification was not significantly correlated with patient survival, metastases, recurrence, or overall histologic grade. However, amplification was significantly associated with increased mitotic activity. Also, amplification of c-erb B-2 showed a significantly negative association with both progesterone and estrogen receptor presence. Progesterone receptor presence correlated significantly with survival.

Hemoglobin Southampton (Casper): characterization of the base mutation.

Hemoglobin Casper is characterized by the substitution of cytidine for thymidine in condon 106 of the beta globin gene. This substitution results in the creation of a new restriction site for Msp I but not for the isoschizimer Hpa II. The restriction pattern following digestion with Msp I reveals a 9.9-kb fragment not seen in normal individuals or following digestion of Casper DNA with Hpa II. This finding confirms the predicted base mutation and indicates that the cytidine in the newly acquired CpG site is methylated.

Spontaneous mutation in the male gamete as a cause of hemophilia A: clarification of a case using DNA probes.

The carrier status of two sisters of the mother of a hemophilic boy was clarified by the use of DNA probes in a family with a single case of hemophilia A and no family history of the disease. The extragenic polymorphic site demonstrated by probe DX13 (locus DXS15) and the intragenic polymorphic site demonstrated by BgI I digestion and a factor VIII partial cDNA probe indicated that the mother of the index case carried a mutation in the X-chromosome received from her nonhemophilic father rather than the X-chromosome received from her mother. In spite of equivocal coagulation data, the mother's two sisters were shown not to be carriers of hemophilia A.

The use of deoxyribonucleic acid probes in the evaluation of hemophilia.

The use of deoxyribonucleic acid (DNA) probes is an important addition to existing laboratory methods for detection of carriers of hemophilia A and B. Both intragenic probes and probes directed at DNA restriction fragment length polymorphisms linked to the disease locus are now available. This technology will aid in genetic counseling of affected families and will impact upon clinical laboratory science in the near future.

Thyroid function tests in thyroid and nonthyroid disease.

Modern day evaluation of thyroid disorders requires a combination of accurate clinical judgement and reliable, sensitive, and specific thyroid functions tests. Principle among the latter are thyroxine (T4) 3, 5, 3'-triiodothyronine (T3), and thyroid-stimulating hormone (TSH). Also playing an important role in special situations are free thyroxine, an assessment of bound and unbound thyroid-binding globulin, TRH stimulation, long-acting thyroid stimulator (LATS), antibodies to thyroid hormone and to thyroid receptors. Basic to interpretation of these tests in the clinical setting is a comprehension of the relationship of the hypothalamus, the pituitary, and the thyroid gland as well as a knowledge of the peripheral metabolism of thyroxine and triiodothyronine. The role of each of these laboratory tests in the evaluation of hyper- and hypometabolic states, their alteration in nonthyroid and other endocrine disorders, and the effects of environmental and physiological factors on these tests are reviewed.

Rapid thawing of fresh frozen plasma.

Fresh frozen plasma (FFP) normally requires about 45 min to thaw in a 37 degrees C water bath when placed inside an additional plastic overbag. That relatively prolonged time may result in non-utilization or delays in delivery of the product, especially, during emergency surgery. One report recommends the use of a microwave oven to overcome those problems. Most blood banks do not have microwave ovens but usually do have water baths at 56 degrees C. Ten units of FFP thawed inside plastic overbags at 37 degrees C required 49.5 +/- 3.9 min and 22 units thawed at 56 degrees C required 28.3 +/- 4 min to thaw. Removal of the plastic overbag reduces the thawing time to 12-13 min at 56 degrees C. The activity Factor V was 85 +/- 15% (65-106%) at 37 degrees C and 80 +/- 21% (47-118%) at 56 degrees C. Factor VIII activity was 86 +/- 21% (59-118%) at 37 degrees C and 90 +/- 37% (46-225%) at 56 degrees C. There were no demonstrable alterations in fibrinogen, PT, APTT, Factor II, VII, IX, and XI between the two thawing temperatures, even after 24 hours of storage at 4 degrees C.

Principles of antibody elution.

Antibody-antigen binding depends upon ionic, hydrophobic, and hydrogen bonds, as well as van der Waals forces and three-dimensional conformation. Antibody elution techniques attempt to break those forces by alterations of ionic strength, pH, thermal agitation, and the use of organic solvents. Because of the heterogeneity of the physical forces involved in binding, no single elution technique finds universal applicability to the disruption of all types of antibody-antigen bonds.