Comparative Evaluation of Rheumatic Activity—A Study of Relationship Between Histologic Changes and Serologic Test Results in Cardiac Surgical Patients

Atrial or ventricular myocardium from patients with surgically corrected rheumatic valvular disease was studied for rheumatic lesions in 86 cases. Histologically active Aschoff bodies were found in 20 per cent of the cases. A slight, but statistically not significant relationship was demonstrated in comparison of elevated serologic tests for rheumatic activity with the presence of Aschoff bodies.     

The Latex Serologic Test for Syphilis—A New Screening Procedure

A new macroscopic screening test for syphilis, the Latex-sts test, is extraordinarily simple. After inactivation of the patient''s serum for 30 minutes at 56°C the test is performed by mixing the patient''s serum with latex particles coated with cardiolipin and a protein fraction obtained from the non-pathogenic Reiter strain of Treponema pallidum. Two to three minutes after mixing, the result of the test is observed on a ringed serologic plate. The sensitivity, specificity and reproducibility of the new test are equivalent to those of the qualitative Venereal Disease Research Laboratory tube test. The advantages of the Latex-sts are that it can be done in a short time, it is simple and it requires a minimum of laboratory equipment. The coated latex particles are stable for 12 months.     

The effects of a glycerin-based blood analog on the testing of bioprosthetic heart valves

Detailed comparisons of aortic valvular flow using saline, with that using a glycerin-based blood analog in a pulse duplicator are reported. The experiments were carried out to determine whether exposure to glycerin caused stiffening of bioprosthetic valve leaflets. For two pericardial bioprostheses and for a mechanical valve we observed a fluid-dependent systolic volume flow, a fluid-dependent regurgitation volume, and fluid-dependent systolic pressure differences. Volume flow changes, both forward and reverse, are independent of valve type. The observed pressure differences, while proportional to fluid density for the mechanical valve, are fluid dependent in a more complicated way for the pericardial valves. However, no trend of changing valvular performance was observed over as much as 80 days of glycerin exposure, indicating that it is unlikely that the fluid-dependent performance was caused by glycerin absorption by the valve leaflets. We conclude that valid performance comparisons between mechanical and bioprosthetic valves may be made using a glycerin-based fluid. Furthermore, it appears that any detailed analysis of the physical mechanisms of valvular flow dissipation will require a properly matched blood analog.     

Engineering the lac permease for purification and crystallization

The lactose permease is being used as a model system for the rational redesign of a membrane protein with the goal of increasing the likelihood of crystallization. Various modifications to the protein have been added for the purposes of purification, stability, and potential for crystallization. The addition of six consecutive histidines at the C-terminus of the protein allows for the rapid purification by nickel-chelate chromatography, and the insertion of an entire protein domain into one of the inner cytoplasmic loops of the permease gives the resulting protein a larger hydrophilic surface area. The increase in polar surface area makes the fusion protein easier to handle and more likely to crystallize. In particular, the introduction of cytochromeb562 ofE. coli into the central hydrophilic domain of the lac permease results in a fusion protein with the transport activity of the permease and the visible absorbance spectrum of the cytochrome. The red permease is very easy to monitor through the steps of expression, purification, concentration, and crystallization.     

Effects ofPax3Modifier Genes on Craniofacial Morphology, Pigmentation, and Viability: A Murine Model of Waardenburg Syndrome Variation

Waardenburg syndrome type 1 is caused by mutations inPAX3.Over 50 humanPAX3mutations that lead to hearing, craniofacial, limb, and pigmentation anomalies have been identified. APAX3mutant allele, segregating in a family, can show reduced penetrance and variable expressivity that cannot be explained by the nature of the mutation alone. TheMus musculus Pax3mutationSp^d(Splotch-delayed, Pax3[formula]), coisogenic on the C57BL/6J (B₆) genetic background, produces in heterozygotes a white belly spot with 100% penetrance and very few other anomalies. By contrast, manySp^d/+ BC₁progeny [F₁♀Sp^d/+ (♀Sp^d/+ B₆× ♂ +/+Mus spretus) × ♂ +/+ B₆] exhibit highly variable craniofacial and pigmentary anomalies. Of the BC₁Sp^d/+ progeny, 23.9% are estimated to be nonviable, and 32.1% are nonpenetrant for the white belly spot. The penetrance and expressivity of theSp^d/+ genotype are controlled in part by the genetic background and the sex of the individual. A minimum of two genes interact withSp^dto influence the craniofacial features of these mice. One of these genes may be either X-linked or sex-influenced, while the other is autosomal. TheA-locus (Agouti) or a gene closely linked toAalso plays a role in determining craniofacial features. At least one additional gene, possibly theA-locus or a gene linked toA,interacts withSp^dand determines the presence and size of the white belly spot. The viability of BC₁mice is influenced by at least three factors:Sp^d,A-locus alleles or a gene closely linked to theA-locus, and the sex of the mouse. These BC₁mice provide an opportunity to identify genes that interact with and modify the expression ofPax3and serve as a model to identify the genes that modify the expression of humanPAX3mutations.     

Localization of mating behavior of releasedBactrocera dorsalis flies on host fruit in an orchard

Oriental fruit flies,Bactrocera dorsalis, cultured in the laboratory for six generations, were released when 12–14 days old in an orchard of nonfruiting host trees that were furnished with either food and water, nonpunctured host fruit, punctured host fruit, or no resources. Nearly all flies of both sexes, all sexual behavior of males, and all mating pairs were observed on trees with fruit. Moreover, on trees with fruit, nearly all flies of both sexes, nearly all sexual behavior of males, and nearly all mating pairs occurred on the fruit itself rather than on the foliage or branches. In a subsequent test, both sexes were found to be strongly attracted to the odor of host fruit. For a polyphagous species of a tropical tephritid, these findings are the first to show a high level of male aggregation and a high amount of male sexual behavior on the fruit of host trees. Findings are discussed in relation to current knowledge of tephritid mating behavior. An additional quality-control test for laboratory cultured males used in the sterile insect technique of fly management is recommended.