Fast protein liquid chromatography (FPLC) of leukaemic cell N-acetyl beta-D hexosaminidases

Leukaemic myeloid and lymphoid cell N-acetyl beta-D glucosaminidase (hexosaminidase) enzymes were fractionated by Fast Protein Liquid Chromatography (FPLC) using high-resolution ion exchange (Mono-S and Mono-Q), gel filtration (Superose-6) and chromatofocusing (Mono-P) columns. Although only one molecular weight species was detected in haemopoietic cells, with an apparent mass of 129 kD, "isoenzyme" variants defined by differences in molecular charge were considerably more diverse than previously thought. Separation of the major Hex forms (A and B) by chromatofocusing indicated that intermediate (I) components were present in most acute leukaemias irrespective of lineage supporting the concept that the I form is a non-specific marker of haemopoietic immaturity. Substrate and inhibitor studies further revealed that leukaemic cell hexosaminidases hydrolyse galactopyranosides at significantly lower rates than glucopyranosides and that the hydrolysis of N-acetyl beta-D glucosamine is inhibited by both glucosamine and galactosamine products.     

The Hunger Games: Homeostatic State-Dependent Fluctuations in Disinhibition Measured with a Novel Gamified Test Battery

Food homeostatic states (hunger and satiety) influence the cognitive systems regulating impulsive responses, but the direction and specific mechanisms involved in this effect remain elusive. We examined how fasting, and satiety, affect cognitive mechanisms underpinning disinhibition using a novel framework and a gamified test-battery. Thirty-four participants completed the test-battery measuring three cognitive facets of disinhibition: attentional control, information gathering and monitoring of feedback, across two experimental sessions: one after overnight fasting and another after a standardised meal. Homeostatic state was assessed using subjective self-reports and biological markers (i.e., blood-derived liver-expressed antimicrobial protein 2 (LEAP-2), insulin and leptin). We found that participants who experienced greater subjective hunger during the satiety session were more impulsive in the information gathering task; results were not confounded by changes in mood or anxiety. Homeostatic state did not significantly influence disinhibition mechanisms linked to attentional control or feedback monitoring. However, we found a significant interaction between homeostatic state and LEAP-2 on attentional control, with higher LEAP-2 associated with faster reaction times in the fasted condition only. Our findings indicate lingering hunger after eating increases impulsive behaviour via reduced information gathering. These findings identify a novel mechanism that may underpin the tendency to overeat and/or engage in broader impulsive behaviours.     

Concordance for Gender Dysphoria in Genetic Female Monozygotic (Identical) Triplets

Archives of Sexual Behavior - The biopsychosocial etiology of gender dysphoria is poorly understood, but current thought suggests a complex interaction of genetic, hormonal, environmental, and...     

The use of trimeric isoleucine-zipper fusion proteins to study surface-receptor-ligand interactions in natural killer cells

The ligands for several activating natural killer (NK) cell receptors have not been identified to date. Soluble receptor fusion proteins can be used to stain target cells for the presence of these unidentified ligands. Here, we describe the generation and use of soluble type I NK cell receptor isoleucine-zipper (ILZ) fusion proteins of the immunoglobulin (Ig) superfamily. ILZ-fusion proteins are easy to produce and purify. They form trimeric complexes in solution and display a higher binding avidity than classical immunoglobulin-fusion proteins. ILZ-fusion proteins do not interact with Fc-receptors and can therefore be used to block receptor-ligand interactions in cellular assays. This makes ILZ-fusion proteins a valuable tool to study receptor-ligand interactions in NK cells and other cellular systems.     

Corneal complications of intraocular surgery

Advances in intraocular surgery have decreased the incidence of corneal complications that result in corneal failure requiring transplantation. Interest continues in further refining surgery to minimize endothelial cell damage. New irrigating solutions, viscoelastic substances, and even new techniques have been introduced. Debate continues over certain issues, such as intraocular lens choice in the absence of capsular support. Improved design has prompted many early critics to regain confidence in the anterior chamber lens. Literature of recent years also reflects a shift in focus toward hastening recovery time and maximizing uncorrected visual acuity through the advantageous control of corneal astigmatism. Several reports this year may herald the next wave of interest, that surrounding intraocular surgery after refractive corneal surgery.     

Sixth Graders Can Take Blood Pressures

A curriculum guide entitled "Heart Health Curriculum Guide" was developed with and by teachers in Peabody Public Schools under a Massachusetts Public Health grant to the American Heart Association. The 67-page manual describes the format of the 12-hour teacher workshop, background physiology of heart/circulatory system, hypertension risk factors, a set of 20 lessons, and evaluating procedures. (Copies may be obtained for $3.00 by writing the corresponding author.) As a result of teaching this unit, sixth grade students in each school ran a Blood Pressure Screening Clinic for their parents and school staff.