Dynamics of Parathyroid Hormone Secretion After Total Parathyroidectomy and Autotransplantation

Secondary hyperparathyroidism is a common complication in uremic patients. Total parathyroidectomy combined with partial autotransplantation into brachioradialis muscle has been the preference among the options for surgical treatment. This study was designed to evaluate the reserve and ability of suppression of autotransplanted parathyroid tissue using dynamics tests. We studied, prospectively, 12 patients in recent (RP) and late (LP) postoperative of total parathyroidectomy with autotransplantation. For analysis of the secretory reserve capacity, we induced hypocalcemia by ethylenediaminetetraacetic acid (EDTA) infusion. Furthermore, for analysis of the ability for parathyroid hormone (PTH) suppression, the hypercalcemia test was used, by intravenous administration of calcium in LP. In RP, there was a decrease in the average serum levels of PTH, phosphorus, and alkaline phosphatase, which ranged from 13 to 231 (87 +/- A 65) pg/ml, 2.3 to 6.2 (3.3 +/- A 1.1) mg/dl, and 77 to 504 (250 +/- A 135) U/L, respectively, similar to that observed in LP. The analysis of the average curve of variations in PTH during testing of the stimulus with EDTA showed lack of secretion in RP and partial response in LP. Impaired suppression ability of the graft in LP was observed in the test with intravenous calcium. Total parathyroidectomy followed by partial autotransplantation was effective in reducing PTH serum levels in patients with terminal kidney disease. The elevation of serum calcium during the suppression test was not able to inhibit the autograft gland secretion of PTH. The assessment of parathyroid graft function demonstrated an inability to respond to the stimulus of hypocalcemia induced by EDTA, although there was a partial recovery, in late postoperative period.

Influence of third-generation oral contraceptives on the complexity analysis and symbolic dynamics of heart rate variability

Objective To evaluate the influence of oral contraceptives (OCs) containing 20 mu mu g ethinylestradiol (EE) and 150 mu mu g gestodene (GEST) on the autonomic modulation of heart rate (HR) in women. Methods One-hundred and fifty-five women aged 24 +/-+/- 2 years were divided into four groups according to their physical activity and the use or not of an OC: active-OC, active-non-OC (NOC), sedentary-OC, and sedentary-NOC. The heart rate was registered in real time based on the electrocardiogram signal for 15 minutes, in the supine-position. The heart rate variability (HRV) was analysed using Shannon`s entropy (SE), conditional entropy (complexity index [CInd] and normalised CInd [NCI]), and symbolic analysis (0V%, 1V%, 2LV%, and 2ULV%). For statistical analysis the Kruskal-Wallis test with Dunn post hoc and the Wilcoxon test (p < 0.05 was considered significant) were applied. Results Treatment with this COC caused no significant changes in SE, CInd, NCI, or symbolic analysis in either active or sedentary groups. Active groups presented higher values for SE and 2ULV%, and lower values for 0V% when compared to sedentary groups (p < 0.05). Conclusion HRV patterns differed depending on life style; the non-linear method applied was highly reliable for identifying these changes. The use of OCs containing 20 mu mu g EE and 150 mu mu g GEST does not influence HR autonomic modulation.

Canine population dynamics: the potential effect of sterilization campaigns

Objective. To analyze, through mathematical modeling, the potential ability of sterilization campaigns to reduce the population density of pet dogs. Methods. Mathematical models were constructed to simulate the canine population dynamics and project the results of control strategies based on several sterilization rates. Results. Even at high sterilization rates (for example, 0.80 year(-1)), it would take approximately 5 years to reduce density by 20%. Even so, other sources of population growth, such as the importing of dogs from other geographic areas, could outweigh the effects of a sterilization program. Conclusions. A program`s effectiveness is contingent upon not only on the sterilization rate, but also the rate of population growth. Sterilization campaigns may potentially reduce population density, but this reduction may not be immediately evident.

Ecological aspects of the free-living ticks (Acari: Ixodidae) on animal trails within Atlantic rainforest in south-eastern Brazil

In a recent ecological study of the ticks on animal trails within an area of Atlantic rainforest in south-eastern Brazil, Amblyomma aureolatum, A. brasiliense, A. incisum, A. ovale and Haemaphysalis juxtakochi were found questing on the vegetation. Most of the ticks recorded by a small, man-made dam on the forest border were A. dubitatum but a few A. brasiliense and A. cajennense, one A. incisum and one H. juxtakochi were also found. The seasonal activity of the ticks indicated that A. incisum and A. brasiliense had one generation/year. On the animal trails, most tick species and stages quested on the vegetation at a height of 30-40 cm above ground level. The questing larvae and adults of A. incisum tended to be found higher, however, with the greatest numbers recorded 40-50 cm (larvae) or 60-70 cm (adults) above ground level. Most of the adult ticks (81.1% -100%), nymphs (78.6%-100%) and larval clusters (100%) found on a forest trail remained questing at the same location over a 24-h period. Carbon-dioxide traps in the rainforest attracted, 50% of the ticks observed questing on the nearby vegetation and, curiously, the CO(2) traps set deep in the forest attracted far fewer ticks than similar traps set by the dam. The ecological relationships between the ticks, their hosts and the rainforest environment are discussed.

Modeling the Dynamics of Viral Evolution Considering Competition Within Individual Hosts and at Population Level: The Effects of Treatment

We consider two viral strains competing against each other within individual hosts (at cellular level) and at population level (for infecting hosts) by studying two cases. In the first case, the strains do not mutate into each other. In this case, we found that each individual in the population can be infected by only one strain and that co-existence in the population is possible only when the strain that has the greater basic intracellular reproduction number, R (0c) , has the smaller population number R (0p) . Treatment against the one strain shifts the population equilibrium toward the other strain in a complicated way (see Appendix B). In the second case, we assume that the strain that has the greater intracellular number R (0c) can mutate into the other strain. In this case, individual hosts can be simultaneously infected by both strains (co-existence within the host). Treatment shifts the prevalence of the two strains within the hosts, depending on the mortality induced by the treatment, which is, in turn, dependent upon the doses given to each individual. The relative proportions of the strains at the population level, under treatment, depend both on the relative proportions within the hosts (which is determined by the dosage of treatment) and on the number of individuals treated per unit time, that is, the rate of treatment. Implications for cases of real diseases are briefly discussed.

Dynamics and Control of Stray Dog Populations

The population dynamics of stray dogs is simulated to assess the effects of sterilization and euthanasia. From simulations representing less than 5 years, sterilization is less efficient than euthanasia to reduce the stray dog population, considering similar rates, but the total number of sterilized dogs is less than the total number of euthanized dogs per km(2) per year. Over 20 years, both strategies have similar efficiency. Beyond a certain rate of dog abandonment, both strategies are inefficient.

Influence of Photoperiod and Temperature on the Larval Behavioral Diapause of Amblyomma cajennense (Acari: Ixodidae)

Larval behavioral diapause was shown to be the major factor controlling the 1-yr generation pattern of Amblyomma cajennense (F.) (Acari: Ixodidae) in Brazil. During fieldwork, this behavior was shown to coincide with long daylength (>12 h) and high mean ground temperature (approximate to 25 degrees C), which prevail during spring-summer in Brazil. The current study evaluated biological parameters of engorged females, their eggs, and the resultant larvae inside plastic pots planted with the grass Brachiaria decumbens Stapf. held in incubators set with different combinations of temperature and photoperiod. Both the long daylength (photoperiod 14:10 [L:D]h) and high temperature (25 degrees C) during larval hatching induced larval behavioral diapause, characterized by the confinement of hatched larvae on the ground below the vegetation for many weeks. When long daylength was present during hatching, but temperature was low (15 degrees C), larvae did not enter diapause. Similarly, when short daylength (10:14 or 12:12) was present during larval hatching, larvae did not enter diapause regardless whether temperature was high (25 degrees C). Termination of diapause was induced by shifting photoperiod from 14:10 to 12:12 or the temperature from 25 to 15 degrees C. When applied to field conditions, the present results indicate that both high ground mean temperature (approximate to 25 degrees C) and long daylength (>12 h) during spring-summer (October-March) are responsible for the induction and maintenance of A. cajennense larval behavioral diapause in the field. Furthermore, both the low ground mean temperature (-20 degrees C) and the short daylength (<12h) during autumn (April-May) are responsible for termination of larval behavioral diapause in the field.

Parasitic dynamics of gastrointestinal nematode infection in the periparturient period of beef cattle in the State of Para

The experiment was conducted to investigate the dynamics of infection by gastrointestinal nematodes during the periparturition period in cows. One hundred and six beef cows were divided into two groups: G I was formed by 42 cows of one and two parturitions, and G2 by 76 cows of three or more parturitions. From the 120 days pre partum until the 90 days post partum, feces were collected for faecal egg counts (EPG) while blood was collected to determine the packed cell volume and hemoglobin levels of each animal, with monthly intervals. In the same intervals the body condition scores (BCS) were evaluated. The mean values standard deviation of the EPG for Cl were equal to 19.4 +/- 42.9, and for G2 31.1 +/- 68.0. No significant differences were observed between Cl and G2 in relation to EPC; and hematological parameters, which remained within normal patterns for both groups. The two groups had higher counts of EPG in the post partum period than in the pre partum period, with averages of 32.5 +/- 55.5 and 51.5 +/- 84.8 for groups Cl and G2, respectively. A significant difference (p < 0.05) in the parameters was observed when comparing the pre and post partum within each group studied resulting in declining values of blood and body score and an increase in EPG in the post partum. The results suggest that the cows may be more susceptible to infection by nematodes from giving birth up to 90 days post partum. However, adult cows, when well-managed, are not an important factor in the epidemiology of gastrointestinal nematodes, even in the post partum period.