Endodontium - together or separately?

Endodontium, otherwise referred to as pulp-dentin complex or endodont. This term includes two tooth tissues: dentin and pulp, which constitute a structural and functional unity. These tissues have a huge, inseparable influence on each other - the pulp (inter alia) nourishes the dentine, while the dentin forms a protective barrier for the pulp. They develop from the papillary tissue (Latin: papilladentis) from mesenchymal tissue. Nevertheless, in clinical practice this structural-functional complex is often treated as two separate tissues, and not as a whole. Adequate knowledge of the structure, function and protective mechanisms of the endodontium produces successful results in the treatment. The appropriate choice and application of the therapeutic methods and materials to the dentin secures vitality of both tissues of this complex.

The number of reproductive workers in highly eusocial Hymenoptera: monogyny and monandry.

Haplodiploidy results in relatedness asymmetries between colony members of highly eusocial Hymenoptera. As a consequence, queen and reproductive workers are more related to their own sons than to each other's male offspring. Kin selection theory predicts multiple optima in male parentage: either the queen or the workers should produce all the males. Nevertheless, shared male parentage is common in highly eusocial hymenopterans. An inclusive fitness model was used to analyze the effect of the number of reproductive workers on male parentage shared by the queen and laying workers by isolating the male component from an inclusive fitness equation using the equal fitness through male condition for each pairwise combination of the three female classes comprised of the queen, laying workers and non-laying workers. The main result of the theoretical analyses showed that the fraction of males produced by workers increases asymptotically with the number of laying workers at an increasingly diminishing rate, tending to an asymptotic value of 0.67. In addition, as the number of laying workers increases, the share of male parentage converges to that of non-laying workers. The diminishing return effect on male parentage share depending on the number of reproductive workers leads us to expect the number of reproductive workers to be relatively small in a stingless bee colony, even in the absence of productivity costs. The available data confirms this hypothesis, as there is an unusually small number of reproductive workers in stingless bee colonies.

Comparative analysis of two sampling techniques for pollen gathered by Nannotrigona testaceicornis Lepeletier (Apidae, Meliponini).

Pollen counts from samples taken from storage pots throughout one year (from October to September) were adjusted by Tasei's volumetric correction coefficient for the determination of pollen sources exploited by two colonies of Nannotrigona testaceicornis in São Paulo, Brazil. The results obtained by this sampling technique for seven months (December to June) were compared with those from corbicula load samples taken within the same period. This species visited a large variety of plant species, but few of them were frequently used. As a rule, pollen sources that appeared at frequencies greater than 1% were found with both sampling methods and significant positive correlations (Spearman correlation coefficient) were found between their values. The pollen load sample data showed that N. testaceicornis gathered pollen throughout the external activity period.

Foraging behavior of Melipona rufiventris Lepeletier (Apinae; Meliponini) in Ubatuba, SP, Brazil.

This study describes how the foraging activity of Melipona rufiventris is influenced by the environment and/or by the state of a colony. Two colonies were studied in Ubatuba, SP (44 degrees 48 W and 23 degrees 22 S) from July/2000 to June/2001. These colonies were classified as strong (Colony 1) and intermediate (Colony 2) according to their general conditions: population and brood comb size and number of food pots. The bees were active from dawn to dusk. The number of pollen loads presented a positive correlation with relative humidity (r(s) = 0.401; p <0.01) and was highest between 70 and 90%. However, it was negatively correlated with temperature (r(s) = -0.228; p <0.01) showing a peak between 18 and 23 degrees C. The number of nectar loads presented a positive correlation with temperature (r(s) = 0.244; p <0.01) and light intensity (r(s) = 0.414; p <0.01); it was greater between 50 and 90% of relative humidity and 20 and 30 degrees C of temperature. They collected more nectar than pollen throughout the day, and were more active between 6 and 9 hours. Workers from Colony 1 (strong) collected nectar in greater amounts and earlier than those from Colony 2 (intermediate). The number of pollen, nectar and resin loads varied considerably between the study days. Peaks of pollen collection occurred earlier in months with longer days and in a hotter and more humid climate. The foraging behavior of M. rufiventris is probably affected by the state of the colony and by environmental conditions, notably temperature, relative humidity, light intensity and length of the day.

Foraging behavior of Melipona rufiventris Lepeletier (Apinae; Meliponini) in Ubatuba, SP, Brazil

This study describes how the foraging activity of Melipona rufiventris is influenced by the environment and/or by the state of a colony. Two colonies were studied in Ubatuba, SP (44° 48Æ W and 23° 22Æ S) from July/2000 to June/2001. These colonies were classified as strong (Colony 1) and intermediate (Colony 2) according to their general conditions: population and brood comb size and number of food pots. The bees were active from dawn to dusk. The number of pollen loads presented a positive correlation with relative humidity (r s = 0.401; p <0.01) and was highest between 70 and 90 percent. However, it was negatively correlated with temperature (r s = -0.228; p <0.01) showing a peak between 18 and 23 °C. The number of nectar loads presented a positive correlation with temperature (r s = 0.244; p <0.01) and light intensity (r s = 0.414; p <0.01); it was greater between 50 and 90 percent of relative humidity and 20 and 30 °C of temperature. They collected more nectar than pollen throughout the day, and were more active between 6 and 9 hours. Workers from Colony 1 (strong) collected nectar in greater amounts and earlier than those from Colony 2 (intermediate). The number of pollen, nectar and resin loads varied considerably between the study days. Peaks of pollen collection occurred earlier in months with longer days and in a hotter and more humid climate. The foraging behavior of M. rufiventris is probably affected by the state of the colony and by environmental conditions, notably temperature, relative humidity, light intensity and length of the day.

Este estudo descreve como a atividade de forrageamento de Melipona rufiventris é influenciada pelo ambiente e/ou pelo estado da colônia. Duas colônias foram estudadas em Ubatuba, SP (44° 48Æ W and 23° 22Æ S), de julho de 2000 a junho de 2001. Estas colônias foram classificadas como forte (Colônia 1) e intermediária (Colônia 2), de acordo com as condições gerais das mesmas: tamanho da população e dos favos de cria e número de potes de alimento. As abelhas foram ativas do amanhecer ao anoitecer. O número de cargas de pólen apresentou correlação positiva com a umidade relativa (r s = 0,401; p <0,01) e foi maior entre 70 e 90 por cento. Entretanto, foi negativamente relacionado com a temperatura (r s = -0,228; p <0,01), com pico entre 18 e 23 °C. O número de cargas de néctar apresentou correlação positiva com a temperatura (r s = 0,224; p <0,01) e com a intensidade luminosa (r s = 0,414; p <0,01); sendo maior entre 50 e 90 por cento de umidade relativa e entre 20 e 30 °C de temperatura. Elas coletaram mais néctar do que pólen ao longo do dia, sendo mais ativas entre 6 e 9 hours. A Colônia 1 (forte) coletou néctar em maiores quantidades e mais cedo que a colônia 2 (intermediária). O número de cargas de pólen, néctar e resina coletadas variou consideravelmente entre os dias de estudo. Os picos de coleta de pólen ocorreram mais cedo nos meses com dias mais longos e com clima mais quente e úmido. O comportamento de forrageio de M. rufiventris é provavelmente afetado pelo estado da colônia e por condições ambientais como temperatura, umidade relativa, intensidade luminosa e comprimento do dia.

Respiratory responses of arbuscular mycorrhizal roots to short-term alleviation of P deficiency.

Arbuscular mycorrhizal (AM) root respiration can impose a respiratory sink on host reserves under low P conditions, but it is not known how AM roots respond to short-term supply of sufficient P. Therefore, the effect of P stress alleviation on the respiration of AM roots was investigated in 5-week-old tomato plants. Plants were inoculated with Glomus mosseae in sand culture and grown hydroponically in a low P (2 microM) nutrient medium for 3 weeks. P stress was alleviated by the supply of 2 mM P for 72 h. With P stress alleviation, the improved root P status coincided with a decline in AM fungal activity and a reduction in root CO2 and O2 fluxes of the AM plants. During P stress alleviation, the AM roots had lower concentrations of organic acids, derived from root-zone CO2 assimilation, in their root exudates. These results show that short-term alleviation of low P conditions in AM roots rapidly affects AM fungal symbiont activity, AM root respiration, and root-zone CO2-derived organic acid metabolism.

Cellular stress triggers the human topoisomerase I damage response independently of DNA damage in a p53 controlled manner.

The 'human topoisomerase I (htopoI) damage response' was reported to be triggered by various kinds of DNA lesions. Also, a high and persistent level of htopoI cleavage complexes correlated with apoptosis. In the present study, we demonstrate that DNA damage-independent induction of cell death using colcemid and tumor necrosis factor alpha is also accompanied by a strong htopoI response that correlates with the onset of apoptotic hallmarks. Consequently, these results suggest that htopoI cleavage complex formation may be caused by signaling pathways independent of the kind of cellular stress. Thus, protein interactions or signaling cascades induced by DNA damage or cellular stress might lead to the formation of stabilized cleavage complexes rather than the DNA lesion itself. Finally, we show that p53 not only plays a key role in the regulation of the htopoI response to UV-C irradiation but also to treatment with colcemid.

Colony strength and queen replacement in Melipona marginata (Apidae: Meliponini).

Physogastric queens of Melipona marginata were removed from their colonies in order to verify the acceptance of a new queen by workers. Colony strength was evaluated according to queen oviposition rate and comb diameters. Replacement was observed seven times. Its occurrence and speed related positively to colony strength, independently of queen's age. In weak colonies, queen replacement was observed only once, following colony population increase that occurred after introduction of combs from another colony. Worker oviposition after queen removal was observed three times: in a strong colony with virgin queens and males, and in two of the weak colonies. In the first two or three days of new queen oviposition, during which most of the eggs were eaten by the queen, worker oviposition preceded almost all provisioning and oviposition processes (POPs). After this period, worker oviposition decreased until it reached around 25% of the POPs. Daily oviposition rate of young queens decreased or was even interrupted by hatching of their first brood.

Colony strength and queen replacement in Melipona marginata (Apidae: Meliponini)

Rainhas fisogástricas de Melipona marginata foram removidas de suas colônias para verificar a aceitação de uma nova rainha pelas operárias. O estado da colônia foi avaliado de acordo com a taxa de oviposição da rainha e o diâmetro dos favos. Em sete dos casos, foi observada a substituição das rainhas, cuja ocorrência e velocidade estiveram relacionadas positivamente ao estado da colônia, independente da idade da rainha. Em colônias fracas, a substituição da rainha foi observada uma única vez, depois que a população da colônia aumentou, após a introdução de favos de cria de outra colônia. Após a remoção da rainha, a oviposição de operárias foi observada três vezes: em uma colônia forte, com rainhas virgens e machos, e em duas das colônias fracas. Nos primeiros dois ou três dias após o início da oviposição pela nova rainha, em quase todos os processos de aprovisionamento e postura (POPs), suas posturas eram precedidas pela oviposição de operárias (sendo a maior parte dos ovos comidos pela rainha), que diminuiu a partir daí até sua observação em cerca de 25% de todos os POPs. A taxa diária de oviposição de rainhas jovens decresceu ou foi interrompida com a eclosão de suas primeiras crias.

Histamine-induced itch converts into pain in neuropathic hyperalgesia.

Physiologically, itch and pain are transmitted in separate specific peripheral C-units and central afferent pathways. Some neuropathic pain patients with intact but sensitized (irritable) primary C-nociceptors have spontaneous pain, heat hyperalgesia, static and dynamic mechanical hyperalgesia. The question was whether cutaneous histamine application induces pain in these patients. For comparison histamine was applied into normal skin experimentally sensitized by capsaicin. Histamine application in the capsaicin-induced primary or secondary hyperalgesic skin did not change the intensity and quality of capsaicin pain. Itch was profoundly inhibited. Conversely, histamine application in neuropathic skin induced severe increase in spontaneous burning pain but no itch. In neuropathies irritable nociceptors may express histamine receptors or induce central sensitization to histaminergic stimuli so that itch converts into pain.

Responses to climatic factors by foragers of Plebeia pugnax Moure (in litt.) (Apidae, Meliponinae)

Flight activity of Plebeia pugnax Moure (in litt.) was studied in six colonies coming from Cunha, SP, from July to October 1994. Twice a week, from 8:00 a.m. to 6:00 p.m., for 5 minutes every half-hour, all the bees entering and leaving the hives were counted. Six hundred counts were made and the materials that foragers carried were recorded. Data were analysed in relation to temperature, relative humidity, light intensity and day time. Foragers' flight activity was relatively constant in a wide range of temperature, from 22 C to 34 C. The minimum temperature for the beginning of flight activity was 14 C. Effective flight activity (when foragers of all colonies were leaving the hives) occurred at 15 C. These bees also flew within a wide range of relative humidity, from 30 percent to 100 percent, decreasing slowly after 50 percent. Flight activity increased as light intensity rose and it has also increased as the hours passed by, reaching a peak around midday and decreasing gradually afterwards. Pollen was collected all day long, while resin collection was relatively constant and debris transportation was slightly higher after 10:00 h. From all known Plebeia species, this one flew on the lowest temperature ever registered for this genus

[Acute poisoning by carbon monoxide affecting the extrapyramidal system]. / Ostre zatrucie tlenkiem wegla z zajeciem ukladu pozapiramidowego.

A case record of a 19-year old women acutely poisoned by carbon monoxide is presented. The state of the patient was very serious with loss of consciousness, cerebral oedema and acute circulatory failure, manifested by pulmonary oedema. The presence of carboxyhemoglobin in concentration of 45% was found in the blood. During the second week after the incident, extrapyramidal symptoms, manifested by hyperkinetic-hypokinetic syndrome with predominant involuntary movement, was observed. The diagnostic examinations of the central nervous system showed necrosis of globus pallidus, external capsule and a part of internal capsule.

[Acute suicidal poisoning with lithium carbonate]. / Ostre samobójcze zatrucie weglanem litu.

A case of the acute poisoning with lithium carbonate is presented. Single hemodialysis did not decrease lithium blood levels significantly. Lithium blood concentration has been slowly decreasing with persisting severe neurological symptoms. Hemodialysis should be repeated until lithium has been released from various tissue compartments.