A Modified Nauta-Gygax Method for Human Brain and Spinal Cord

Relatively thick frozen sections of formalin-fixed human brains are treated subsequently with an equal-parts mixture of 1% oxalic acid and 1% hydroquinone for 30-60 min, 0.005% chromic acid for 10 min, 4% hydrobromic acid for 6 min, 1% phosphotungstic acid for 15 min, 0.05% potassium permanganate for 3-10 min, equal parts of 1% oxalic acid and 1% hydroquinone for 2-5 min. After thorough washing in distilled water, the sections are then soaked in 1.5% silver nitrate for 15-30 min, Laidlaw's ammoniacal silver carbonate for 2.5 min, and then reduced in the Nauta-Gygax reducer. The sections are washed and then passed through 1% sodium thiosulfate for 1-2 min; again washed, dehydrated, cleared and covered with synthetic resin.     

A FIVE-YEAR STUDY OF PREMATURITY

To get a comprehensive picture of prematurity and neonatal death or survival, all factors on the maternal and fetal records that might be pertinent were recorded. This information, having to do with factors such as age, gravida of the mother, blood group incompatibility, period of gestation, weight at birth, type of delivery, medication and anesthesia administered to the mother, is presented in tabular form.In the study of perinatal mortality it was noted that failure to establish normal pulmonary ventilation is the most common cause of death in the neonatal period. Maternal history of relative infertility, that is, previous abortions, stillbirths and premature deliveries, was the most impressive finding in the stillborn series.In the follow-up study of premature infants who survived the neonatal period, 8.5 per cent were found to be severely handicapped. In four cases the handicap was due to congenital anomalies, in two others probably to infection, leaving 12 with complications possibly ascribable to prematurity. Six of these had retrolental fibroplasia as a major handicap. In seven, mental retardation was the presenting problem. Most of the handicapped children had multiple handicaps, which included spasticity, delayed motor development, strabismus, etc. The incidence of the necessity for corrective measures for feet and legs appeared relatively high.In general, survivors compared favorably with the rest of the childhood population. Complications and twinning were associated inordinately often.     

Pulse radiolysis study of the interaction of retinoids with peroxyl radicals

Vitamin A (retinol) and its derivatives-retinal and retinoic acid-are known for their ability to inhibit lipid peroxidation. Antioxidant actions of retinoids have been attributed to chain-breaking by scavenging of peroxyl radicals. Based on chemical analysis of retinoic acid degradation products formed during microsomal lipid peroxidation, it was previously suggested that retinoids interact with peroxyl radicals forming free carbon-centered radical adducts. However, it can be argued that such a mode of antioxidant action of retinoids is not sufficient to fully explain their effectiveness at inhibiting lipid peroxidation, which in many systems is comparable to, or even exceeds, that of alpha-tocopherol. In order to elucidate the mechanism of interaction of retinoids with peroxyl radicals, (trichloromethyl)peroxyl radical was generated by pulse radiolysis, and its interactions with retinoids solubilized in Triton X-100 micelles were followed by kinetic absorption spectroscopy. All retinoids--retinol, retinal, and retinoic acid--interacted with the peroxyl radical, and at least two transient products were detected. One of these products, absorbing at 590 nm, was identified as retinoid cation radical. Therefore, we postulate that, apart from formation of radical adducts, retinoids may also scavenge peroxyl radicals by electron transfer.     

Re-establishment of Calluna vulgaris (L.) Hull in an eight-year grazing experiment on upland acid grassland

Upland heathland is an internationally important habitat but a large area in the UK has been degraded to acid grassland by intensive livestock grazing. Re-establishment of dwarf shrubs, particularly Calluna vulgaris (L.) Hull, is a key objective for restoring heathland on these sites. A replicated plot-scale experiment was set up to examine effects of disturbance and seed addition on C. vulgaris establishment in a Nardus stricta L. grassland under three grazing regimes: sheep only (1.5 ewes ha^?1 for 10 months per year); cattle only (0.5 heifers ha^?1 in summer only); and, the cattle regime combined with sheep (1.0 ewes ha^?1 for 10 months per year). Early results of the experiment have been reported previously but it was not known if these results were an indication of the longer-term restoration success. Here we evaluate the success of the restoration methods (disturbance, seeding treatments and grazing regime) eight years after the treatments began. In seeded plots, young C. vulgaris plants had greatest above-ground height, dry weight and shoot length if grazing was excluded or the cattle-only regime was applied. C. vulgaris cover was greatest, and increased most, in plots that had been disturbed, seeded and ungrazed or subjected to the cattle-only regime. The vegetation in these plots also became more similar to reference sites with 50% or more cover of C. vulgaris. The invasive Juncus effusus L. was more frequent in disturbed and grazed plots but less frequent in plots with C. vulgaris established from added seed. Previous results that showed the benefits of disturbance and seeding treatments were still valid but changes in the vegetation composition were still occurring and longer-term studies will be needed to determine when grazing regimes including sheep might be reintroduced.     

A unique spatial arrangement of the snRNPs within the native spliceosome emerges from in silico studies

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Highlights? We present a computational procedure for fast matching of thousands of conformers ? We obtained a unique model localizing the snRNPs within the native spliceosome ? The 5 snRNPs are accommodated mostly within the large subunit of the spliceosome ? The large spliceosomal cavity emerges as the site of mRNA binding and splicing     

Further localization of ETS1 indicates that the chromosomal rearrangement in Ewing sarcoma does not occur at fra(11)(q23)

Summary A genomic probe homologous to 5.4 kb of the c-ets-1 gene was hybridized in situ to chromosomes expressing fra(11)(q23). This probe hybridized distal to the fragile site, which is just distal to the midpoint of band 11q23.3. This result localizes ETS1 from the FRA11B locus to 11q24. The result also distinguishes the FRA11B locus from the site of translocation at 11q23-q24 in the Ewing sarcoma- and peripheral neuroepithelioma-specific t(11;22), indicating that the chromosomes of a previously reported patient heterozygous for fra(11)(q23) did not rearrange at this fragile site to give rise to Ewing sarcoma. This adds to the mounting evidence against individuals with fragile sites being predisposed to developing cancer.     

Morphometric analysis of hepatocytes from rats subjected to compound 48/80-induced anaphylactic shock

Morphometric and biochemical techniques were used to analyze hepatic glycogen, endoplasmic reticulum, and mitochondrial matrix granules in rats treated with compound 48/80 to induce an anaphylactic-like state of shock. Thirty minutes after insult there was a significant decrease in glycogen and mitochondrial matrix granules, an increase in rough endoplasmic reticulum (RER), and no change in smooth endoplasmic reticulum (SER). Less glycogen in experimental rats substantiated a previously described glycogenolytic response to compound 48/80. The decrease in matrix granules implies a loss and/or shift in intramitochondrial calcium as occurs in epinephrine-induced glycogenolysis in the rat. Since other glycogenolytic agents, e.g. glucagon, and starvation stimulate an increase in SER presumably from RER, the present morphological data suggest the increase in RER may precede proliferation of SER from RER.     

Intracellular Mycobacterium tuberculosis Exploits Host-derived Fatty Acids to Limit Metabolic Stress

Recent data indicate that the nutrients available to Mycobacterium tuberculosis (Mtb) inside its host cell are restricted in their diversity. Fatty acids and cholesterol appear more favored; however, their degradation can result in certain metabolic stresses. Their breakdown can generate propionyl-CoA, which gives rise to potentially toxic intermediates. Detoxification of propionyl-CoA relies on the activity of the methylcitrate cycle, the methylmalonyl pathway, or incorporation of the propionyl-CoA into methyl-branched lipids in the cell wall. The current work explores carbon flux through these pathways, focusing primarily on those pathways responsible for the incorporation of propionyl-CoA into virulence-associated cell wall lipids. Exploiting both genetic and biochemical rescue, we demonstrate that these metabolic pressures are experienced by Mtb inside its host macrophage and that the bacterium accesses host fatty acid stores. The metabolism of these host lipids expands the acetyl-CoA pool and alleviates the pressure from propionyl-CoA. These data have major implications for our appreciation of central metabolism of Mtb during the course of infection.     

Evidence of doubly uniparental inheritance of the mitochondrial DNA in Polititapes rhomboides (Bivalvia,Veneridae): Evolutionary and population genetic analysis of F and M mitotypes

Doubly uniparental inheritance (DUI) is a particular mitochondrial DNA inheritance mode reported in a number of bivalves. DUI species show two types of mtDNA, one transmitted from females to daughters and sons (F mitotype) and another one from males to sons (M mitotype). In Veneridae, the existence of DUI has been investigated in several species but it was found in only two of them. In this study, we obtained partial sequences of rrnL, cytb and cox1 genes of males and females of Polititapes rhomboides from NW Spain and we demonstrated the existence of heteroplasmy in males, as expected under DUI. F and M mitotypes showed a taxon-specific phylogenetic pattern and similar evolutionary rates. We focused on cox1 for population genetic analysis, examining separately F and M mitotypes, but also F mitotypes from females (F_♀) and males (F_♂). In all cases, cox1 bears signs of strong purifying selection, with no apparent evidence of relaxed selection in the M genome, while the divergence between F and M genomes is in agreement with the neutral model of evolution. The cox1 polymorphism, higher at the M than at the F genome, also shows clear footprints of genetic hitchhiking with favourable mutations at other mtDNA loci, except for F_♂. In terms of population structure, results suggest that the pattern depends on the examined mitotype (F, F_♀, F_♂ or M).