The Effect on Body Temperature and Melatonin of A 39-H Constant Routine with Two Different Light Levels at Nighttime

Eight healthy subjects were studied during 39-h spans (from 07:00 on one day until 22:00 the second) in which they remained awake. During one experiment, subjects were exposed to 100 lux of light between 18:00 and 8:00, and during a second experiment, they were exposed to 1000 lux during the same time span. Throughout the daytime period, they were exposed to normal daylight (1500 lux or more). The nighttime 1000-lux light treatment suppressed the melatonin metabolite aMT6s, while the 100 lux treatment did not. On the treatment day, the 1000 lux, in comparison to the 100 lux, light treatment resulted in both an elevated temperature minimum and a delay in its clock-time occurrence overnight. No real circadian phase shift in the temperature, urinary melatonin, or Cortisol rhythms was detected after light treatment. This study confirmed that nocturnal exposure to lower light intensities is capable of modifying circadian variables more than previously estimated. The immediate effects of all-night light treatment are essentially not different from those of evening light. This may be important if bright light is used to improve alertness of night workers. Whether subsequent daytime alertness and sleep recovery are affected by the protocol used in our study remains to be determined.     

Cytological changes in oral mucosa in denture stomatitis

The cytological patterns associated with the atrophic and hyperplastic forms of denture stomatitis (DS) were studied in 94 patients with DS and 33 controls. Forty percent of patients with DS and 30% of patients in the control group had a positive culture for Candida. When compared to the smears from the control group patients, the smears from patients with DS presented a higher amount of: i) cytological cellular material; ii) fungal cells; iii) cells of the intermediate and parabasal types; iv) cells of the intermediate type with a positive culture for Candida; and v) polymorphonuclear leukocytes, preferentially in association with a positive culture for Candida. Conversely, smears from the control group showed a higher percentage of cells of the superficial type than those of the patients with DS. Although no specific changes in the DS-affected mucosa have been observed by cytology, we consider that this is a useful, easy and inexpensive technique that gives important information about the inflamed mucosa it can be used in the treatment and control of these patients.     

A Linkage Map of the Canine Genome

A genetic linkage map of the canine genome has been developed by typing 150 microsatellite markers using 17 three-generation pedigrees, composed of 163 F₂individuals. One hundred and thirty-nine markers were linked to at least one other marker with a lod score ≥ 3.0, identifying 30 linkage groups. The largest chromosome had 9 markers spanning 106.1 cM. The average distance between markers was 14.03 cM, and the map covers an estimated 2073 cM. Eleven markers were informative on the mapping panel, but were unlinked to any other marker. These likely represent single markers located on small, distinct canine chromosomes. This map will be the initial resource for mapping canine traits of interest and serve as a foundation for development of a comprehensive canine genetic map.     

Diversification across a heterogeneous landscape

Adaptation to contrasting environments across a heterogeneous landscape favors the formation of ecotypes by promoting ecological divergence. Patterns of fitness variation in the field can show whether natural selection drives local adaptation and ecotype formation. However, to demonstrate a link between ecological divergence and speciation, local adaptation must have consequences for reproductive isolation. Using contrasting ecotypes of an Australian wildflower, Senecio lautus in common garden experiments, hybridization experiments, and reciprocal transplants, we assessed how the environment shapes patterns of adaptation and the consequences of adaptive divergence for reproductive isolation. Local adaptation was strong between ecotypes, but weaker between populations of the same ecotype. F1 hybrids exhibited heterosis, but crosses involving one native parent performed better than those with two foreign parents. In a common garden experiment, F2 hybrids exhibited reduced fitness compared to parentals and F1 hybrids, suggesting that few genetic incompatibilities have accumulated between populations adapted to contrasting environments. Our results show how ecological differences across the landscape have created complex patterns of local adaptation and reproductive isolation, suggesting that divergent natural selection has played a fundamental role in the early stages of species diversification.     

Reading shell shape: implications for palaeoenvironmental reconstructions. A case study for bivalves from the marine Quaternary of Argentina (south-western Atlantic)

Most research on bivalves from the south-western Atlantic used morphological (shell) characters for taxonomic discriminations. Dominant Veneroids from Argentinian Quaternary coastal deposits exhibit wide morphological variation – often making objective discriminations difficult/impossible, which could be objectively described and compared through geometric morphometrics techniques. This work focuses on comparison of geometric morphometrics methods applied to fossil and modern shells, to assess inter- and intra-generic variations. Three approaches were considered: landmarks (L), semi-landmarks (SL) and outlines. Shell shape analyses for different time spans (Pleistocene, fossil Holocene and modern) and areas (Patagonia and Bonaerensian) showed that Elliptic Fourier analysis (EFA), Landmarks and Landmarks plus Semilandmarks (L+SL) can discriminate at generic levels: Mactra, Mulinia (Mactridae) vs. Pitar, Protothaca, Eurhomalea, Clausinella (Veneridae). L and L+SL are powerful for inter/intraspecific distinctions of Mactra. Variability of Mactra isabelleana includes the remaining nominal ‘species’ (transitional morphs). Causal environmental factors of (phenotype) variation could be addressed for modern environments (substrate, salinity and energy). Subtrigonal-inflated shells predominate in muddy, quieter, shallow mixo-polyhaline waters; ovate-elongate-compressed in sandy, poly-euhaline, deeper habitats. Differential spatial distribution (and abundance) across time responds to Late Quaternary high sea-level stands: transgressive maxima allowed higher salinity in marginal-marine areas and optimal conditions for Mactra isabelleana contrasting with scarcer records in the Mar Argentino today.     

Differential phagocytosis of Leishmania mexicana promastigotes and amastigotes by monocyte‐derived dendritic cells

Leishmania species are dimorphic protozoan parasites that live and replicate in the gut of sand flies as promastigotes or in mammalian hosts as amastigotes. Different immune cells, including DCs, and receptors differ in their involvement in phagocytosis of promastigotes and amastigotes and in recognition of different Leishmania species. In the case of L. mexicana, differences in phagocytosis of promastigotes and amastigotes by DCs and participation of C‐type lectin receptors (CLRs) have not been established. In the present study, flow cytometry and confocal microscopy were used to investigate the phagocytosis by monocyte‐derived dendritic cells (moDCs) of L. mexicana promastigotes and amastigotes in the presence or absence of immune serum during various periods of time. Blocking antibodies against mannose receptors and DC‐SIGN were used to explore the participation of these receptors in the phagocytosis of L. mexicana by moDC. The major differences in interactions of L. mexicana promastigotes and amastigotes with moDC were found to occur within the first 3 hr, during which phagocytosis of promastigotes predominated as compared with opsonization of promastigotes and amastigotes. However, after 6 hr of incubation, opsonized promastigotes were preferentially phagocytosed as compared with unopsonized promastigotes and amastigotes and after 24 hr of incubation there were no differences in the phagocytosis of promastigotes and amastigotes. Finally, after 3 hr incubation, DC‐SIGN was involved in the phagocytosis of promastigotes, but not of amastigotes.     

A comparative study of morphometric measurements of nucleoli in uveal melanomas from electron micrographs and plastic-embedded and paraffin-embedded sections

Morphometric measurements of nucleoli were done on uveal melanomas from surviving and nonsurviving patients. The melanomas were embedded in paraffin and plastic, and measurement data from Papanicolaou-stained paraffin-embedded sections, toluidine blue-stained plastic-embedded sections and scanning transmission electron micrographs (STEM) of plastic-embedded sections were compared. The results showed that one parameter, the coefficient of variation (CV) of nucleolar area, correctly classified 80% of the cases as to survival when plastic-embedded material was used and 70% of the cases when paraffin-embedded material or STEM micrographs were used. The inverse standard deviation of the nucleolar area was a better predictor of outcome than was the CV of nucleolar area only in the paraffin-embedded sections. The nucleolar measurements were most easily and rapidly performed in the plastic-embedded sections.