Separation distress and attachment in surrogate-reared squirrel monkeys.

Surrogate-reared infant squirrel monkeys were exposed to various conditions of separation from their surrogate. Infants showed significant increases in plasma levels of cortisol when they were placed in an unfamiliar environment during the separation period. Changes in behavior, but not cortisol, were observed under conditions in which the surrogate was removed and the infant left in the home cage. These results differ from those previously obtained with mother-reared infants. It is concluded that surrogate-reared infant squirrel monkeys do not show the same separation response or attachment to their rearing figure as do mother-reared infants.     

Micropurification techniques in the analysis of amyloid proteins

This review describes the different microtechniques developed for the extraction and purification of amyloid proteins from small specimens of fresh and formalin fixed tissues. These procedures differ with respect to solvent type, extraction conditions, and protein purification strategy. The advantages and disadvantages of the different microtechniques are discussed by taking into consideration tissue type (fresh of fixed) and size, amyloid type, and its content in the tissue. The review demonstrates the applicability of these techniques for the immunochemical and chemical characterisation of amyloid in different clinical forms of amyloidosis and in experimental small animal models. The clinical value of the applied microtechniques and their importance in the study of the pathogenesis of amyloid related diseases are outlined.     

Neuromuscular organization of the pectoralis (pars thoracicus) of the pigeon (Columba livia): implications for motor control

The pectoralis (pars thoracicus) of the domestic pigeon (Columba livia) is divisible into two anatomical parts, the pars sternobrachialis (SB) and the pars thoracobrachialis (TB). Innervation to this complex is from rostral and caudal branches of the brachial ventral cord. In four anesthetized pigeons, the distribution of muscle units associated with each nerve branch was mapped after prolonged stimulation of each nerve and subsequent analysis for muscle fiber glycogen. An additional three animals were used to analyze the morphology, distribution, and histochemical profiles of the muscle fibers in the SB and TB subregions. Fibers were characterized on the basis of their reactions for myofibrillar adenosine triphosphates (alkaline and acid preincubation) and reduced nicotinamide adenine dinucleotide diaphorase (NADH-D). The SB is primarily innervated by the rostral nerve branch and the TB by the caudal nerve branch. For two-thirds of the muscle's length, the SB is separated from the TB by an aponeurosis, the membrana intermuscularis (MI). SB and TB fibers located posteroventral to the caudal margin of the MI are innervated variously by both nerves. Two populations of fibers were recognized, distinguishable primarily by 1) fiber diameter and 2) density of the NADH-D reaction product. Compared to the TB, the SB possesses a higher average percentage of large fibers. Within the SB but not the TB the percentage of large fibers increases from deep to superficial. These data support our previous findings that the pars thoracicus of the pigeon is partitioned into at least two functional subunits, each with a potential for independent action on the wing during flight.     

Contribution to carrier detection and genetic counselling in X linked retinoschisis.

X linked retinoschisis (RS) is a vitreoretinal disease resulting from microcystic degeneration of the macula associated with peripheral lesions. The disease gene has already been assigned to the distal short arm of the X chromosome (Xp22.2) by linkage studies. In order to contribute both to a better localisation of the RS locus and to genetic counselling in RS families, we have carried out a clinical and genetic analysis in seven pedigrees. We show, first, that in contrast with previous reports, heterozygote carriers frequently express the disease, and display peripheral retinal alterations similar to those found in affected males. Second, while distal markers DXS16, DXS207, and DXS43 are closely linked to the disease locus, a high level of recombination events was found with centromeric markers, namely DXS274, DXS41, and DXS164. These findings must be taken into account for both carrier detection and prenatal diagnosis in X linked RS.     

Rapid detection of respiratory syncytial virus in nasopharyngeal aspirates by a commercial enzyme immunoassay.

A commercial enzyme immunoassay (EIA) for the rapid detection of respiratory syncytial virus (RSV) in respiratory secretions was evaluated by comparison with both virus isolation in HEp-2 cells and indirect immunofluorescence (IFA) staining of exfoliated respiratory cells. Initial examination of 80 nasopharyngeal aspirates collected from infants with acute respiratory illness showed that the RSV EIA was positive for 21 of 24 specimens positive by virus isolation or IFA (87.5% sensitivity) and negative for 53 of 56 specimens negative by virus isolation and IFA (95% specificity). The EIA appears to be an acceptable and more rapid test than virus isolation for the detection of RSV, especially for laboratories in which prompt inoculation of specimens is not always possible. IFA staining with commercial bovine anti-RSV serum was found to be the most sensitive and rapid test for the detection of RSV. However, three of four specimens positive by IFA and negative by virus isolation were not cultured under optimal conditions. In addition, the IFA test requires a highly trained technologist to interpret the staining results.     

In vitro cartilage tissue engineering with 3D porous aqueous-derived silk scaffolds and mesenchymal stem cells

Adult cartilage tissue has limited self-repair capacity, especially in the case of severe damages caused by developmental abnormalities, trauma, or aging-related degeneration like osteoarthritis. Adult mesenchymal stem cells (MSCs) have the potential to differentiate into cells of different lineages including bone, cartilage, and fat. In vitro cartilage tissue engineering using autologous MSCs and three-dimensional (3-D) porous scaffolds has the potential for the successful repair of severe cartilage damage. Ideally, scaffolds designed for cartilage tissue engineering should have optimal structural and mechanical properties, excellent biocompatibility, controlled degradation rate, and good handling characteristics. In the present work, a novel, highly porous silk scaffold was developed by an aqueous process according to these criteria and subsequently combined with MSCs for in vitro cartilage tissue engineering. Chondrogenesis of MSCs in the silk scaffold was evident by real-time RT-PCR analysis for cartilage-specific ECM gene markers, histological and immunohistochemical evaluations of cartilage-specific ECM components. Dexamethasone and TGF-beta3 were essential for the survival, proliferation and chondrogenesis of MSCs in the silk scaffolds. The attachment, proliferation, and differentiation of MSCs in the silk scaffold showed unique characteristics. After 3 weeks of cultivation, the spatial cell arrangement and the collagen type-II distribution in the MSCs-silk scaffold constructs resembles those in native articular cartilage tissue, suggesting promise for these novel 3-D degradable silk-based scaffolds in MSC-based cartilage repair. Further in vivo evaluation is necessary to fully recognize the clinical relevance of these observations.     

Human bone marrow stromal cell responses on electrospun silk fibroin mats

Fibers with nanoscale diameters provide benefits due to high surface area for biomaterial scaffolds. In this study electrospun silk fibroin-based fibers with average diameter 700+/-50 nm were prepared from aqueous regenerated silkworm silk solutions. Adhesion, spreading and proliferation of human bone marrow stromal cells (BMSCs) on these silk matrices was studied. Scanning electron microscopy (SEM) and MTT analyses demonstrated that the electrospun silk matrices supported BMSC attachment and proliferation over 14 days in culture similar to native silk fibroin (approximately 15 microm fiber diameter) matrices. The ability of electrospun silk matrices to support BMSC attachment, spreading and growth in vitro, combined with a biocompatibility and biodegradable properties of the silk protein matrix, suggest potential use of these biomaterial matrices as scaffolds for tissue engineering.     

Studies of the mechanisms of bradykinin generation in hereditary angioedema plasma

BACKGROUND: Factor XII-dependent bradykinin formation is thought to be responsible for the swelling associated with the various forms of C1 inhibitor deficiency, and complement activation is augmented during attacks of swelling. OBJECTIVES: To further elucidate the interactions of the kinin-forming cascade that lead to complement activation during attacks of swelling and to determine whether fibrinolysis is augmented as well. METHODS: We compared spontaneous and kaolin-induced activation of normal plasma with the plasma of patients with hereditary angioedema. RESULTS: Hereditary angioedema plasma demonstrated augmented factor XII activation, production of factor XIIf, prekallikrein activation, and high-molecular-weight kininogen cleavage, and, as a result, bradykinin formation was markedly increased. Baseline levels of C4a and plasmin-alpha 2 antiplasmin complexes increased, and, on activation with kaolin, levels increased further. CONCLUSIONS: All parameters indicative of activation of the bradykinin-forming cascade are activated in hereditary angioedema plasma vs normal plasma. Production of factor XIIf, demonstrated for the first time in whole plasma, may be responsible for C1 activation based on C4a production. The factor XII-dependent fibrinolytic cascade is also activated.     

The effects of separation and reunion on the behavior of mother and infant squirrel monkeys

Mother and infant squirrel monkeys that lived together in a socially restricted environment were separated for a period of seven days after the infants had become relatively independent, and were then reunited. Behavioral observations before, during, and after separation indicated that (1) female infants became independent of their mothers earlier than males, (2) neither mothers nor infants were severely affected by separation, and (3) an increase in attachment occurred following reunion only when the mother had a limited history of maternal experience. These results suggest that (1) certain characteristics in the maternal behavior of the squirrel monkey facilitate readjustment in mothers and infants following maternal separation, (2) maternal experience can influence the mother-infant relationship following a period of separation, and (3) the independence of infants from their mothers may be a function of both sex and species.     

Endothelial cells inhibit receptor-mediated superoxide anion production by human polymorphonuclear leukocytes via a soluble inhibitor

Confluent monolayers of bovine pulmonary artery endothelial cells (BPAE) or human umbilical vein endothelial cells (HUVE) inhibited by 80 to 90% the production of O2- by added human neutrophils (PMNs) stimulated by plasma membrane receptor-mediated activators (formylmethionylleucylphenylalanine [fMLP], opsonized zymosan, heat-killed Staphylococci), but not by non-plasma membrane receptor-mediated activators (phorbol myristate acetate and delta-hexachlorocyclohexane). Degranulation induced by fMLP was also inhibited by BPAE. Inhibition was not affected by eicosatetraynoic acid (ETYA) or indomethacin. To assess the role of cell-cell contact, 0.45-microns-pore culture plate inserts were employed to prevent PMN-endothelial cell contact during incubation. A similar amount of inhibition of stimulated PMNs superoxide production was seen as compared to PMN-endothelial incubations where contact occurred. A soluble component released by BPAE monolayers, when added to PMNs, duplicated the inhibition seen by BPAE-PMN co-incubation. Incubation of BPAE with adenosine deaminase did not reduce inhibition of O2- production compared to controls without adenosine deaminase. There was no evidence of endothelial scavenging of O2- generated by hypoxanthine-xanthine oxidase, and inhibition of endothelial superoxide dismutase did not diminish the inhibitory effort. We conclude that cell contact is not required for BPAE inhibition of fMLP-stimulated O2- production by PMN, and that scavenging of superoxide anion is not the mechanism. The inhibitor appears to be a polypeptide with an apparent molecular weight between 1,000 and 10,000 D and does not appear to be adenosine, an arachidonate metabolite, or superoxide dismutase. The mechanism may involve down-regulation of plasma membrane receptor-mediated activation of PMNs.