Dermatopathic Lymphadenopathy—A Clinicopathologic Analysis of Lymph Node Biopsy Over a 15-Year Period

Forty cases of dermatopathic lymphadenopathy were found in a series of 906 consecutive lymph node biopsies (4.8 per cent).The histologic development and progression of the disease was correlated with the clinical state of the patient.In 35 of 40 cases the patients had active skin disease at the time of the biopsy; one of the remaining five patients had Hodgkin''s disease, one had multiple myeloma and one had secondary syphilis. In the other two, no organic cause was found.In nine cases (22.5 per cent), the histological pattern typical of dermatopathic lymphadenopathy was associated with malignant lymphoma. Except for two biopsies, which showed coexisting malignant lymphoma and dermatopathic lymphadenopathy, no histologic features were found which distinguished patients with malignant lymphoma from the remainder.While the pathogenesis of the lymph node changes remains obscure, the histologic features suggest that it is at least in part an immune response, although the nature of the responsible antigen is unknown.     

Exome sequences and multi‐environment field trials elucidate the genetic basis of adaptation in barley

Broadening the genetic base of crops is crucial for developing varieties to respond to global agricultural challenges such as climate change. Here, we analysed a diverse panel of 371 domesticated lines of the model crop barley to explore the genetics of crop adaptation. We first collected exome sequence data and phenotypes of key life history traits from contrasting multi‐environment common garden trials. Then we applied refined statistical methods, including some based on exomic haplotype states, for genotype‐by‐environment (G×E) modelling. Sub‐populations defined from exomic profiles were coincident with barley's biology, geography and history, and explained a high proportion of trial phenotypic variance. Clear G×E interactions indicated adaptation profiles that varied for landraces and cultivars. Exploration of circadian clock‐related genes, associated with the environmentally adaptive days to heading trait (crucial for the crop's spread from the Fertile Crescent), illustrated complexities in G×E effect directions, and the importance of latitudinally based genic context in the expression of large‐effect alleles. Our analysis supports a gene‐level scientific understanding of crop adaption and leads to practical opportunities for crop improvement, allowing the prioritisation of genomic regions and particular sets of lines for breeding efforts seeking to cope with climate change and other stresses.     

Different long-term effects of bilateral and unilateral nucleus basalis lesions on rat cerebral cortical neurotransmitter content

Young adult rats received either unilateral or bilateral ibotenic acid infusions in their nucleus basalis, destroying most of the cholinesterase-staining neurons in that region. Cerebral cortex levels of choline acetyltransferase, somatostatin, neuropeptide Y, and monoamines were then assayed 2.5 and 10 months after bilateral lesions, or, 2.5, 10, and 14 months after unilateral lesions. Entorhinal and cerebral cortex levels of several amino acid transmitters were also measured. As expected, choline acetyltransferase activity was decreased in the frontal cortex ipsilateral to the ibotenic acid infusion in unilaterally or bilaterally lesioned animals. Parietal cortex concentrations of somatostatin and neuropeptide Y were altered by lesioning in a complicated, time-dependent manner. Thus, while unilateral lesions transiently decreased or had no effect on these neuropeptide levels, bilateral lesions elevated the level of each neuropeptide by over 100% at 10 months. Other cortical transmitter systems investigated appeared to be less affected by nucleus basalis-lesions. Unilateral lesions had no effect on prefrontal cortex norepinephrine, serotonin, or dopamine content at 14 months post-lesioning. These different neurochemical effects of unilateral and bilateral nucleus basalis lesions may be important for developing a model for the trans-synaptic effects of cortical cholinergic deafferentation.     

Rare internal C4A4 repeats in the micronuclear genome of Oxytricha fallax.

Approximately 20,000 different short, linear, macronuclear DNA molecules are derived from micronuclear sequences of Oxytricha fallax after conjugation. These macronuclear DNAs are terminated at both ends by 20 base pairs of the sequence 5'-dC4A4-3'. Sequences homologous to this repeat (C4A4+) are also abundant in the micronuclear chromosomes, but most reside at their telomeres. Here we show that nontelomeric C4A4 clusters of 20 base pairs or longer exist in only a few hundred copies per micronuclear genome. This demonstrates that nearly none of the 20,000 sequence blocks of micronuclear DNA destined to be macronuclear DNA molecules can be flanked by full-length (20-base pair) C4A4 clusters, and therefore C4A4 repeats must be added to most, if not all, macronuclear telomeres during macronuclear development. Six internal micronuclear C4A4+ loci were cloned, and their structural relationships with macronuclear and micronuclear sequences were examined. The possible origins and functions of these rare, micronuclear internal C4A4 loci are discussed.