Chitosan: evaluation of a new hemostatic agent

Topically applied chitosan fails to improve the control of bleeding in a liver laceration model when compared to pressure alone in both normal and heparinized rats, and both chitosan and pressure alone are significantly less effective in controlling bleeding than the application of thrombin. In addition, our histologic results suggest that there may be an increased inflammatory response by the healing liver following topical application of chitosan.     

Immunohistochemical localization of fibronectin in the chinchilla cochlea

The purpose of this study was to better understand the molecular composition of the cochlea. Fibronectin (FN), a well characterized adhesive glycoprotein, was localized by immunofluorescence microscopy in fresh and fixed cochlear tissues, and in fixed kidney tissue, using a polyclonal, affinity-purified, rabbit, anti-fibronectin antibody and a secondary antibody coupled to FITC. The FN antibody was free from cross-reactivity with other known basement membrane and cell matrix molecules. FN reactivity in the cochlea was most intense in the basilar membrane, latero-basal borders of Boettcher's cells, otic capsule, endothelial basement membranes (particularly those of the stria vascularis), and as a diffuse, fan-shaped network radiating into the spiral ligament. Little FN labelling was present in the epithelial basement membranes. Negative control tissue showed no immunoreactivity; whereas, positive kidney control tissue showed appropriate FN immunoreactivity in the mesangium of the glomerulus. The most significant finding of this study was that FN is a major component of the basilar membrane and its distribution appears to correspond to the amorphous ground substance. FN was not localized in the organ of Corti or at the tips of the hair-cell stereocilia.     

Experimental verification of a model describing the occupied volume by polymers in solution

A relation is proposed which yields the occupied volume by macromolecular chains in solution. The experimental verification of the model is carried out by a viscometric study of the ternary system polymer A/polymer B/solvent. More precisely the viscometric study permits the determination of the critical concentration c^** corresponding to the incipient overlap of spherical coils.     

Donor insemination: child development and family functioning in lesbian mother families

Findings are presented of a comparative study investigating the family relationships and the emotional and gender development of children raised in lesbian mother families. A total of 30 lesbian mother families with 4-8 year old children created as a result of donor insemination (DI) were compared with 38 heterosexual families with a DI child and with 30 heterosexual families who had a naturally conceived child. A variety of assessment measures, including a standardized interview and questionnaires from the parents and psychological testing of the child were used to collect the data. The quality of the couples' relationships and the quality of the mother-child interaction did not differ between lesbian mother families and either of the heterosexual family groups. The quality of the interaction between the social mother and the child in lesbian families was superior to that between the father and the child in both groups of heterosexual families. Childrens' own perception of their parents was similar in all family types; the social mother in lesbian families was regarded by the child to be as much a 'parent' as the father in both types of heterosexual families. With regard to their emotional/behavioural development, boys and girls raised in lesbian mother families were well adjusted and their gender role development did not differ from that of children raised in heterosexual families. These results indicate that child and family development in lesbian mother families is similar to that of heterosexual families.      

Donor insemination: Dutch parents' opinions about confidentiality and donor anonymity and the emotional adjustment of their children

Results from a comparative study investigating 38 donor insemination (DI) Dutch families with 4-8 year old children are presented. The aims of this study were to investigate parents' opinions on the issues of confidentiality and donor anonymity, to assess the emotional development of the children, and to examine in DI families the association between secrecy with regard to the use of a donor and the emotional adjustment of the children. The DI families were compared to families with a child conceived by in-vitro fertilization (IVF) and to families with a naturally conceived child. Secrecy appeared to be associated with DI and not with IVF: 74% of the DI parents intended not to inform the child about the way in which she/he was conceived, whereas none of the IVF parents intended to keep the secret. Only one set of DI parents and two sets of IVF parents had actually told the child. As to donor anonymity, a spread of opinions appeared among DI parents; 57% preferred an anonymous donor, 31% would have liked non- identifying information about the donor, 9% preferred the donor's identity to be registered and 3% remained unsure. Parents' major concern was to know more about the medical/genetic background of the donor. Mothers and fathers in the DI families differed in their opinions concerning the issues of confidentiality and donor anonymity: fathers, more often than mothers, were secretive with regard to the use of a donor and husbands, more often than their wives, were in favour of donor anonymity. With regard to the emotional development of the children, more emotional/behavioural problems were revealed among DI children than among children who were naturally conceived. No association was found between secrecy and the emotional/behavioural adjustment of the children.      

Interleukin-4 downregulates interleukin-6 production in human peripheral blood mononuclear cells

We report that recombinant human interleukin-4 (IL-4) downregulates interleukin-6 (IL-6) production by human peripheral blood mononuclear cells (PBMC). PBMC were preincubated for up to 24 hr in the presence of IL-4 (100 U/ml) and then activated with lipopolysaccharide B Escherichia coli 026:B6 (LPS, 10 micrograms/ml), recombinant human tumor necrosis factor-alpha (TNF-alpha, 200 U/ml), or Concanavalin A (Con A, 10 micrograms/ml). Although all these signals induced IL-6 production, IL-4-treated cells produced significantly reduced levels of IL-6 protein. This effect was dose and time dependent. We conclude that IL-4 is a potent downregulatory modulator of IL-6 expression in human PBMC.     

Mitochondrial DNA mutation and heteroplasmy in type I Leber hereditary optic neuropathy.

Leber hereditary optic neuropathy (LHON) is a maternally inherited disorder characterized by bilateral acute or subacute loss of central vision, primarily in young males. A G----A single base mutation at 11778nt of the mitochondrial genome which eliminates a SfaNI restriction site [Wallace et al., 1988; Holt et al., 1989; Hotta et al., 1989; Singh et al., 1989; Vilkki et al., 1989; Yoneda et al., 1989; Stone et al., 1990; Lott et al., 1990.] has been found in more than 60% of the families with LHON studied. We studied 25 persons from 4 families with LHON using SfaNI and Mae III digestion of a 201 base pair polymerase chain reaction (PCR) product encompassing the 11778nt mutation. The loss of the SfaNI site and the acquisition of a Mae III site at 11778nt were identified in all maternal relatives of the LHON families studied. The mutation was heteroplasmic in all affected individuals, female carriers, and males at-risk. The heteroplasmy of mitochondrial DNA (mtDNA) was also identified by direct DNA sequencing of PCR amplified by direct DNA sequencing of PCR amplified mtDNA digested by SfaNI or Mae III. It appears that the proportion of the mutant mtDNA correlates with the severity of the disease.     

Mitochondrial genetics of Coprinus: Recombination of mitochondrial genomes

Summary The formation of the sexual mycelium or dikaryon in the basidiomycete Coprinus cinereus involves exchange and migration of nuclei without accompanying exchange of mitochondria. The dikaryotic growth which appears around the periphery of mated monokaryons has exclusively the mitochondrial genome of the recipient cells. Recombination of mitochondrial genomes is not, however, precluded during dikaryosis. Using monokaryons with different mitochondrial gene mutations, [acu-10] causing cytochrome aa ₃ deficiency and[cap-1.1] conferring resistance to chloramphenicol, it was shown that recombinant mitochondria arise in the zone of contact of mated monokaryons.