Electron microscopic studies of the DNA of defective and standard pseudorabies virions.

DNA from standard and defective virus particles was analyzed by electron microscopy. Upon partial denaturation the DNA molecules from standard pseudorabies virus showed distinct denaturation patterns. The molecules are asymmetrical with respect to adenine-thymidine (A-T) content, having several A-T-rich regions on the “left” side and only one on the “right” side of the molecule. The fact that a distinct denaturation map was obtained indicates that the molecules are not circularly permuted. On the extreme left of the molecule a segment of approximately 0.5 μm invariably contained denatured regions, whereas this was not evident on the right side of the molecule. Thus, if the molecule is terminally redundant, the redundant region covers a relatively small part of the viral genome. The contour length of the DNA molecules present in defective, interfering particles was found to be similar to that of standard DNA. Under partial denaturation conditions a distinct segment of DNA (1.1 μm in length) was found to be tandemly repeated in defective DNA. The number of repeats in different molecules varied. In some of the DNA molecules as many as 17 consecutive repeats were found, whereas in others no repeats were seen. Repeated segments were not detected in standard DNA.     

Role of glycoproteins of pseudorabies virus in eliciting neutralizing antibodies

The experiments described in this paper were designed to assess the role of the various virus glycoproteins of pseudorabies virus (PrV) in eliciting the production of neutralizing antibodies during the normal course of infection of swine. They also address the question of the degree of antigenic variation within each glycoprotein between different virus isolates. The results show the following: Antigenic variation between strains of PrV isolated from different geographic areas are readily detectable; antigenic differences between strains isolated from the same geographic area are less common. No antigenic drift in glycoprotein gII was observed. Glycoprotein gIII and, to some extent, also glycoprotein gI showed a high level of antigenic drift. The neutralizing activity of pooled convalescent sera of swine is not directed against glycoprotein gI. A large part of the neutralizing activity of pooled convalescent sera of swine is directed against glycoprotein gIII.     

Solid phase interleukin 2

Interleukin 2 was bound to Sepharose beads in order to assess its potential bioactivity in vitro. Although the cytokine was attached to the solid phase via a standard chemical reaction for covalent coupling, it was spontaneously released into culture medium in an active form during short-term incubation. Release was absolutely dependent on the availability of soluble protein in the incubation medium, and it was greater at 37 than at 4 degrees C. Approximately 80% of the cytokine attached to the Sepharose beads was recovered in the medium after appropriate incubation for several days. The release of interleukin 2 from the solid phase resulted from the dissolution of aggregated cytokine. Noncovalent self-aggregation of interleukin 2 onto solid surfaces represents an unusual biochemical property that has implications for the molecular interactions of the cytokine with the solid phase, for the use of bound interleukin 2 in preparative or analytical modes, and for the development of immunotherapy for patients with solid tumors.     

HPA polymorphism in sub-Saharan African populations: Beninese, Cameroonians, Congolese, and Pygmies

The frequency of human platelet antigen-1 (HPA-1) to HPA-11w (excluding HPA-8w) and HPA-15 systems was studied in four sub-Saharan populations: Beninese, Congolese (Democratic Republic of Congo Kinshasa), Cameroonians, and Aka pygmies (Central African Republic). No report of HPA prevalence has previously been published concerning these populations which are characterized by the highest HPA-2b gene frequencies of any reported to date (Aka 0.393, Benin 0.292, Cameroon 0.237, and Congo 0.224) and at lesser degree HPA-5b (Aka 0.405, Congo 0.268, Cameroon 0.254, and Benin 0.182). This study is of great importance (i) particularly in the context of the diversity caused by the population migrations, we may observe today in our hospitals (ii) to confirm that the Pygmy population with distinctive frequencies (absence of the HPA-1b, HPA-2b, and HPA-5b highest frequencies) is an isolated population.     

Freeze Dried Platelets for HLA Alloantibodies Absorption

Antibodies to HLA–A and B are specifically absorbed onto platelets. A method of absorption of these antibodies using freeze dried platelets is described. This method allows long-term storage and standardized absorption procedures. Anti-DR antibodies and cold lymphocytotoxins are recovered in the supernatant.     

Three-dimensional aqueous-derived biomaterial scaffolds from silk fibroin

A new all-aqueous process is described to form three-dimensional porous silk fibroin matrices with control of structural and morphological features. The result of this process are scaffolds with controllable porosity and pore sizes that fully degrade in the presence of proteases, unlike prior methods to generate silk-based biomaterials that required the use of organic solvent treatments to impart control of structure and stability in aqueous environments, with low rates of proteolytic hydrolysis. A mechanism is proposed for this novel process that imparts physical stability via hydrophobic interactions. Adjusting the concentration of silk fibroin in water, and the particle size of granular NaCl used in the process, leads to the control of morphological and functional properties of the scaffolds. The aqueous-derived scaffolds had highly homogeneous and interconnected pores with pore sizes ranging from 470 to 940 microm, depending on the mode of preparation. The scaffolds had porosities >90% and compressive strength and modulus up to 320 +/- 10 and 3330 +/- 500 KPa, respectively, when formed from 10% aqueous solutions of fibroin. The scaffolds fully degraded upon exposure to protease during 21 days, unlike the scaffolds prepared from organic solvent processing. These new silk-based three-dimensional matrices provide useful properties as biomaterial matrices due to the all-aqueous mode of preparation, control of pore size, connectivity of pores, degradability and useful mechanical features. Importantly, this process offers an entirely new window of materials properties when compared with traditional silk fibroin-based materials.     

First reported case of streptococcus pyogenes infection with toxic shock-like syndrome in Italy

A 43-year-old male who sustained a superficial hand injury developed streptococcal toxic shock-like syndrome and died within 48 hours. The clinical course of the illness in this previously well patient was rapid and fulminant. The organism responsible was a group A beta-hemolytic streptococcus which was identified as opacity factor negative, M serotype 1, T type 1. The organism produced streptococcal pyrogenic exotoxins B and C, but no detectable exotoxin A although it carriedspeA, the gene for exotoxin A. This is the first case reported in Italy, and further emphasizes the virulence of these organisms and the rapidity with which the illness can progress.     

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.