Stain Technology: A Phenylhydrazine-Leucofuchsin Sequence for Staining Nerves and Nerve Endings in the Integument of Poultry

This sequence for staining cutaneous nerves and nerve endings uses 1% formic acid as a fixative for 1 hr, followed by two treatments of 5 min each in 6% H₂SO₄. The tissue is then submerged in fresh 5% phenylhydrazine hydrochloride for 30 min, washed in running tap water for 10 min, and given a 5 min soak in distilled water. The specimen is placed in Lillie's “cold Schiff” reagent for 4 hr; transferred to 6% H₂SO₄, 4 changes of 5 min each; washed in distilled water, 3 changes of 5 min each; dehydrated in acetone, 4 changes of 10 min each; and cleared in 2 changes of methyl benzoate, the 1st for 1 hr and the 2nd until the tissue clears. Nerve fibers stain pinkish-purple; muscles also take up the stain, yet the nerves are discernible from the muscles. All other tissue remain unstained.     

Ink Perfusion for Displaying Capillaries in the Chicken

A chicken was anesthetized with Na-phenobarbital, 130 mg/kg, and the external ischiatic artery was exposed. Heparin, 90 units/kg, was injected into the brachial vein, after which a cannula was inserted into the exposed ischiatic artery. Heat was applied to the head to produce vasodilation. Perfusion through the cannula was made at about 150 mm Hg pressure and consisted of 30 ml of a biological type of Pelikan ink to which was added NaNO₂ to make a 0.02% solution. After the bird was killed by an overdose of anesthetic, the skin around the perimeter of the femoral feather tract was cauterized, the tract removed, attached to a stainless steel wire net, fixed for 1 hr in 10% formic acid, then dehydrated in 4 changes of acetone, 1 hr each, followed by a 5th change for 12 hr. The dehydrated specimens were placed in methyl benzoate, the 1st change for 1 hr and the 2nd until clear (3-15 hr). This procedure exhibits small vessels and capillary networks within the integument, but if only the vessels larger than capillaries are to be studied, they can be shown by slowly injecting 15-30 ml of the perfusion mixture into a peripheral vein. The still beating heart will distribute the ink to other regions of the body, thus allowing the vessels to be traced in excised tissue.     

A possible role for the synaptonemal complex in chiasma maintenance

It is suggested that in addition to whatever function the synaptonemal complex may serve with respect to crossing over, it may serve a previously unsuspected function, i.e. one which normally assures regular meiotic chromosome disjunction in most organisms. This is the provision of the sister chromatid cohesiveness which is probably required for chiasma maintenance until anaphase I and may also be required in the centromere regions for maintenance of dyad integrity until anaphase II. Attention is directed to suggestive correlations of occurrence of normal synapsis through pachytene (homologous or non-homologous) with instances of sister chromatid cohesiveness at later meiotic stages and conversely of lack of normal synapsis with failure of sister chromatid cohesiveness. Chromosome behavior is compared in trisomies and in material homozygous for several meiotic mutants.     

Investigating the relationship between olfactory acuity,disgust, and mating strategies

Although humans' sense of smell is relatively diminished compared to other species, olfaction is still a central sensory modality through which people evaluate both potential threats and prospective romantic partners. Despite olfaction's role in interpersonal relationships and disease avoidant responses, however, it remains unknown whether variation in olfactory acuity is associated with disease- and mating-relevant psychological constructs and behaviors. In the current exploratory study, we examined the relationships between olfactory acuity, disgust sensitivity, and mating strategies in a sample of undergraduate students (N = 162) at a university in the Southern United States using an extended assessment of olfactory acuity (measuring olfactory threshold, discrimination, and identification). Results revealed that people with greater discrimination acuity were higher in dispositional sexual disgust, but not pathogen or moral disgust. People with greater discrimination acuity were also less inclined towards short-term mating. Further, sexual disgust mediated the relationship between discrimination acuity and short-term mating orientation. These results provide further evidence for the importance of olfaction and olfaction-related disgust in close relationships.     

A History of Proteolipids: A Personal Memoir

This review is a personal memoir of the history of proteolipids and is limited to aspects of the field with which the author has been involved in one way or another. The discovery of proteolipids was a serendipitous observation made in the course of the study of sulfatides. Initial focus was on the chemical characterization of brain proteolipids, their behavior under different conditions and their identification as the major protein of CNS myelin. The sequence of PLP was obtained using solid phase protein sequencing techniques. This, in turn, made possible a new era in which biochemical, cellular and molecular approaches could be applied to address new questions about PLP. Identification of genetic defects in the PLP molecule and its regulation has contributed to understanding myelin biology. Studies of the encephalitogenic activity of PLP in animal models have influenced the views of inflammatory processes in multiple sclerosis. Despite remarkable progress, much remains to be learned about the structure and function of PLP.