Effect of different pacing strategies on 4-km cycling time trial performance.

In cycling, there is a body of evidence that supports that an all-out start strategy is superior to an even-pacing strategy, but it is unknown whether an all-out start strategy is superior to a self-paced strategy. In the present study, we investigated the effects of three different pacing strategies on 4-km cycling time trial performance. After preliminary trials (familiarization trials and a baseline 4-km cycling time trial), in a randomized and counterbalanced order, twelve male cyclists (32.3±7.2 years old, maximum rate of O2 uptake (V̇O2peak) 4.3±0.4 L/min) completed: 1) a self-paced 4-km cycling time trial; 2) an all-out start (∼10 s), followed by maintenance of the average baseline trial power for the first km and self-paced cycling for the remaining trial (all-out+mean); and 3) an all-out start (∼10 s), followed by a power 5% above the average baseline trial power for the first km and self-paced cycling for the remaining trial (all-out+5%mean). Although there was a significant interaction between power and distance (P=0.001) with different power distribution profiles throughout the trial, there was no significant difference (P=0.99) between the three strategies for overall exercise performance (self-paced 379.8±13.9 s, all-out+mean 380.0±16.0 s, and all-out+5%mean 380.2±11.5 s). Oxygen uptake, rating of perceived effort, and heart rate were also similar across the pacing strategies. Different all-out start strategies did not confer additional benefits to performance compared to a self-paced strategy.

Effect of different pacing strategies on 4-km cycling time trial performance

In cycling, there is a body of evidence that supports that an all-out start strategy is superior to an even-pacing strategy, but it is unknown whether an all-out start strategy is superior to a self-paced strategy. In the present study, we investigated the effects of three different pacing strategies on 4-km cycling time trial performance. After preliminary trials (familiarization trials and a baseline 4-km cycling time trial), in a randomized and counterbalanced order, twelve male cyclists (32.3±7.2 years old, maximum rate of O2 uptake (V̇O2peak) 4.3±0.4 L/min) completed: 1) a self-paced 4-km cycling time trial; 2) an all-out start (∼10 s), followed by maintenance of the average baseline trial power for the first km and self-paced cycling for the remaining trial (all-out+mean); and 3) an all-out start (∼10 s), followed by a power 5% above the average baseline trial power for the first km and self-paced cycling for the remaining trial (all-out+5%mean). Although there was a significant interaction between power and distance (P=0.001) with different power distribution profiles throughout the trial, there was no significant difference (P=0.99) between the three strategies for overall exercise performance (self-paced 379.8±13.9 s, all-out+mean 380.0±16.0 s, and all-out+5%mean 380.2±11.5 s). Oxygen uptake, rating of perceived effort, and heart rate were also similar across the pacing strategies. Different all-out start strategies did not confer additional benefits to performance compared to a self-paced strategy.

Enteric methane, lactation performances, digestibility, and metabolism of nitrogen and energy of Holsteins and Jerseys fed 2 levels of forage fiber from alfalfa silage or corn silage.

Our objective was to determine the effects of replacing alfalfa silage (AS) neutral detergent fiber (NDF) with corn silage (CS) NDF at 2 levels of forage NDF (FNDF) on enteric methane (CH4), lactation performance, ruminal fluid characteristics, digestibility, and metabolism of N and energy in Holstein and Jersey cows. Twelve Holstein and 12 Jersey cows (all primiparous and mid-lactation) were used in a triplicated split-plot 4 × 4 Latin square experiment, where breed and diet formed the main and subplots, respectively. The 4 iso-nitrogenous and iso-starch dietary treatments were arranged as a 2 × 2 factorial with 2 levels of FNDF [19 (low FNDF, LF) and 24% (high FNDF, HF) of dry matter] and 2 sources of FNDF (70:30 and 30:70 ratio of AS NDF to CS NDF). Soyhull (non-forage NDF) and corn grain were respectively used to keep dietary NDF and starch content similar across diets. Total collection of feces and urine over 3 d was performed on 8 cows (1 Latin square from each breed). The difference in dry matter intake (DMI) between Holsteins and Jerseys was greater when fed AS than CS. Compared with Jerseys, Holstein cows had greater body weight (48%), DMI (34%), fat- and protein-corrected milk (FPCM; 31%) and CH4 production (22%; 471 vs. 385 g/d). However, breed did not affect CH4 intensity (g/kg of FPCM) or yield (g/kg of DMI), nutrient digestibility, and N partitioning. Compared with HF, LF-fed cows had greater DMI (10%), N intake (8%), and FPCM (5%), but they were 5% less efficient (both FPCM/DMI and milk N/intake N). Compared with HF, LF-fed cows excreted 11 and 17% less urinary N (g/d and % of N intake, respectively). In spite of lower (2.5%) acetate and higher (10%) propionate (mol/100 mol ruminal volatile fatty acids) LF-fed cows had greater (6%) CH4 production (g/d) than did HF-fed cows, most likely due to increased DMI, as affected mainly by the soyhulls. Compared with AS, CS-fed cows had greater DMI (7%) and FPCM (4%), but they were less efficient (5%), and CH4 yield (g/kg of DMI) was reduced by 8%. In addition, per unit of gross energy intake, CS-fed cows lost less urinary energy (15%) and CH energy (11%) than did AS-fed cows. We concluded that, in contrast to level and source of FNDF, breed did not affect digestive and metabolic efficiencies, and, furthermore, neither breed nor dietary treatments affected CH4 intensity. The tradeoff between CH4 and N losses may have implications in future studies assessing the environmental effects of milk production when approached from a whole-farm perspective.

Replacing alfalfa hay with triticale hay has minimal effects on lactation performance and nitrogen utilization of dairy cows in a semi-arid region of Mexico.

In the semi-arid highlands of central Mexico, triticale (× Triticosecale L.) is emerging as an alternative, less water-demanding forage crop than alfalfa for dairy cattle. Studies reported here were aimed at evaluating triticale hay (TH) relative to alfalfa hay (AH) for lactating cow performance, apparent digestibility, N partition, and ruminal degradation kinetics of dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF). Study 1 was conducted on a privately owned farm. Four barns were used to conduct 4 replicated 3 × 3 Latin squares (1 barn = 1 square), where each barn included 3 pens (experimental units) receiving 1 of 3 dietary treatments. Each pen had 62 Holstein dairy cows. All diets included a forage-to-concentrate ratio of 42:58 (DM basis), which is typical for intensive dairy farms of the region. Dietary treatments were formulated to replace AH with TH on a CP basis, and included (DM basis) 15.1% AH and 0% TH, 9.0% AH and 7.4% TH, and 0% AH and 16.4% TH. Diets were iso-energetic (1.64 Mcal of net energy for lactation/kg of DM) and iso-nitrogenous (17.9% CP). Pen-level DM intake and milk production were from all cows in the pen, but pen-level milk composition, apparent digestibility, and N partitioning were from 8 cows (observational units) randomly selected in each pen. Orthogonal contrasts were used to determine linear and quadratic effects of increasing TH from 0 to 7.4, and 16.4% of dietary DM. Although DM intake was not affected, there was a tendency for CP intake to decline linearly and for NDF intake to increased linearly as TH replaced AH in the diet. Milk production declined linearly by 0.077 kg/d for each additional percentage unit of TH in the diet, which amounted to a 3.5% decline when TH replaced AH entirely. However, no effect was observed on energy-corrected milk production because of a compensatory linear effect of increasing milk fat concentration with the incorporation of TH in the diet. Total-tract NDF digestibility tended to increase linearly by 18.5%, but no differences were detected for urinary urea-N excretion and for N utilization estimated as milk N/(fecal N + urinary N + milk N). Study 2 was an in situ trial conducted to determine the degradation kinetics of AH and TH used in study 1. In spite of differences in degradation kinetics parameters for DM, CP, and NDF, only NDF effective ruminal degradation tended to be greater for TH than AH. Replacing AH with TH at the level typically found in intensive dairy farms of the semi-arid regions of Mexico had minimal effects on milk production and N utilization.

Biocidal effects of Piper hispidinervum (Piperaceae) essential oil and synergism among its main components.

In this study we evaluated the effect of a pressure gradient (1-2 atm) in the extraction and composition of the essential oil (EO) of Piper hispidinervum by steam distillation. We also evaluated the insect antifeedant effects (Spodoptera littoralis, Leptinotarsa decemlineata, Myzus persicae and Rhopalosiphum padi) and nematicidal activity (Meloidogyne javanica) of the oils, their major components and their synergistic interactions. Safrole was the major component (78-81%) followed by terpinolene (5-9%). The EOs tested were effective insect antifeedants. Safrole, explained most of the insect antifeedant action of P. hispidinervum EOs. When safrole and terpinolene were tested in binary combinations, low ratios of safrole improved the antifeedant effects of terpinolene. P. hispidinervum EOs caused higher mortality of M. javanica juveniles than their major components. In binary combinations, low ratios of terpinolene increased the nematicidal effects of safrole. The EO treatment strongly suppressed nematode egg hatching and juvenile infectivity. P. hispidinervum EOs affected the germination of S. lycopersicum and L. sativa mostly at 24 h of treatment, being L. sativa the most sensitive. Safrole moderately affected germination and root growth of L. sativa, S. lycopersicum and L. perenne. Terpinolene only affected S. lycopersicum root growth.

Sodium caseinate induces mouse granulopoiesis.

OBJECTIVE AND DESIGN: Sodium caseinate (CasNa) induces differentiation and M-CSF production in mouse band granulocytes in vitro; however, it is not yet known if this molecule can also induce the proliferation and activation of the granulocyte lineage in vivo. In this work we evaluated the induction in vivo of granulopoiesis and the activation of granulocytes in mice treated with CasNa. MATERIAL OR SUBJECTS: BALB/c male mice 8-12 weeks old were used. TREATMENT: The animals were inoculated intraperitoneally with 1 ml of CasNa (10% in PBS p/v) four times (every 48 h). METHODS: Granulocyte proliferation was evaluated by flow cytometry; activation was evaluated by phagocytic indices. The cytokine was measured using an ELISA assay. RESULTS: We show that CasNa increased bone marrow granulopoiesis percentage (38.35 ± 10.88 vs. 64.94 ± 34.14 BrdU+/Gr-1+ cells) and the granulocytes generated presented increased phagocytic indices (0.3 ± 0.1 vs. 0.6 ± 0.11, p < 0.05). We also show that G-CSF (974 ± 411 vs. 3189 ± 350 pg/ml, p < 0.05) and GM-CSF increased in serum, but only G-CSF in bone marrow plasma. CONCLUSIONS: CasNa induces granulopoiesis with functional granulocytes, suggesting that this molecule could be an innate immune system activator.

Abordaje transcalloso de craneofaringioma supraselar / Carniopharyngioma suprasellar transcallosal approach

El craniofaringioma es una neplasia epitelial benigna usualmente de origen supraselar, considerado un tumor hipofisiario de crecimiento lento, puede causar varios grados de hipopituitarismo. En este artículo se describe un caso manejado en el Hospital Dr. Patrocinio Peñuela Ruíz (IVSS) y se realiza una revisión bibliográfica acerca de la presentación, patología y tratamiento. Escolar masculino de 8 años, inicia enfermedad de 1 mes de evolución caracterizada por cefalea frontal de moderada intensidad, disminución de la agudeza visual, movimientos reiterativos a predominio de hemicuerpo derecho. En una primera intervención se coloca válvula de derivación ventrículo peritoneal por hidrocefalia obstructiva: al mes y medio se realizó exéresis completa del tumor mediante abordaje transcalloso. La evolución postoperatoria fue de difícil manejo por presentar alteraciones metabólicas e hidroelectrolíticas. En RMN se evidencia ausencia total del tumor. El trastorno hidroelectrol¡tico se mantuvo a pesar del tratamiento médico: 24 días después del acto quirúrgico, fallece por hipernatremia incohercible. La lesión apareció en nuestro paciente a los 8 años, como una tumoración de 6 por 4 cm. La clínica se presenta 1 mes antes de su ingreso, caracterizada por cefalea, trastornos visuales, movimientos repetitivos a predominio de hemicuerpo derecho sin alteraciones endocrinas al momento del diagnóstico. Mediante abordaje quirúrgico transcalloso se pudo resecar totalmente una tumoración que histopatológicamente determinó un adamantinoma. Sin embargo, el manejo multidisciplinario es condición sine cua non para terminar de lograr el éxito quirúrgico en cirugías tan d¡fíciles como la del paciente.

Seroprevalence of infection by Coxiella burnetii in Canary Islands (Spain).

THE AIMS OF OUR STUDY WERE: (i) to know the seroprevalence of Coxiella burnetii infection in the Canary Islands, (ii) to evaluate its epidemiologic features and (iii) to compare the rates of seroprevalence using two different cut-offs (1:20 and 1:80) for the diagnosis of past infection. METHODS: We analysed a representative sample of the canarian population. 662 sera were tested. For the detection of IgG and IgM antibodies against C. burnetii phase II antigens an immuofluorescence assay was used. The serologic screening for IgG detection begun with a 1:20 dilution. A titer of IgG > or = 1:80 along with a negative IgM were used as criteria for previous infection. RESULTS: At an IgG antibody titer against C. burnetii of 1:80 as diagnostic for past infection, the observed global seroprevalence was 21.5%. If the cut-off used was 1:20, the observed prevalence increased up to 35.8% (p = 0.001). Significantly different seroprevalence rates were obtained at these different cut-offs when results were analysed for groups of age and socioeconomic status, but not for either the island of origin or for farmers. CONCLUSION: Our results strongly suggest that Coxiella burnetii infection is endemic in all the Canary Islands. Although it is more frequent in males above 30 years old, it do affect people of all ages, and thus it should be borne in mind in the face of any acute febrile syndrome.

Isolated renoureteric aspergilloma due to Aspergillus flavus: case report and review of the literature.

In this paper we describe a case in which acute renal colic was associated with elimination of multiple hyphal masses of Aspergillus flavus. Also, we reviewed the literature on similar cases and we found a similar pattern characterized by a marked male predominance, association with at least one underlying medical condition that predisposes to fungal infection, the presence of local symptoms resembling acute ureteral colic, and the absence of systemic manifestations. Moreover, our data suggest that Aspergillus balls must be suspected when a diabetic and intravenous drug user presents with acute renal colic and that non-obstructive renal aspergillosis may be initially treated with itraconazole.

Heart rate modulates the slow enhancement of contraction due to sudden left ventricular dilation.

In isovolumic blood-perfused dog hearts, left ventricular developed pressure (DP) was recorded while a sudden ventricular dilation was promoted at three heart rate (HR) levels: low (L: 52 +/- 1.7 beats/min), intermediate (M: 82 +/- 2.2 beats/min), and high (H: 117 +/- 3.5 beats/min). DP increased instantaneously with chamber expansion (Delta(1)DP), and another continuous increase occurred for several minutes (Delta(2)DP). HR elevation did not alter Delta(1)DP (32.8 +/- 1.6, 33.6 +/- 1.5, and 34.3 +/- 1.2 mmHg for L, M, and H, respectively), even though it intensified Delta(2)DP (17.3 +/- 0.9, 20.7 +/- 1.0, and 26.8 +/- 1.2 mmHg for L, M, and H, respectively), meaning that the treppe phenomenon enhances the length dependence of the contraction component related to changes in intracellular Ca(2+) concentration. Frequency increments reduced the half time of the slow response (82 +/- 3.6, 67 +/- 2.6, and 53 +/- 2.0 s for L, M, and H, respectively), while the number of beats included in half time increased (72 +/- 2.9, 95 +/- 2.9, and 111 +/- 3.2 beats for L, M, and H, respectively). HR modulation of the slow response suggests that L-type Ca(2+) channel currents and/or the Na(+)/Ca(2+) exchanger plays a relevant role in the stretch-triggered Ca(2+) gain when HR increases in the canine heart.

[Seroepidemiological study of hepatitis A in Gran Canaria (Spain)]. / Estudio seroepidemiológico de hepatitis A en Gran Canaria.

BACKGROUND: The aim of this study was to assess the seroprevalence and the risk factors of hepatitis A virus (HAV) infection in the population from Gran Canaria (Spain) and to determine at which age pre-vaccination testing would be useful. METHODS: A transversal observational study of the presence of HAV antibodies (IgG) on serum samples obtained from a population ranging from 8 months to 63 years old was performed between January 1995 and December 1996. IgG anti-HAV were detected by a commercial immunoenzyme assay. The study included 547 persons resident in Gran Canaria. Epidemiological data (age, sex, number of family members, educational level, urban/rural residence and previous history of hepatitis) were gathered through a personal interview. Confusing variables were excluded by mean a multiple logistic regression analysis. RESULTS: Global prevalence of anti-HAV (IgG) was 36.0% (CI 95% 32.0-40.0). The prevalence of anti-HAV increased significantly with age from 2.3% in children under 4 years until 98.9% in older than 40 years (OR 3956.0; CI 95% 241.7-64,753.5). Only three independent data (age, sex and educational level) were significantly associated with HAV seroprevalence. A previous history of hepatitis A was present only in 4.8% of HAV-positive subjects. CONCLUSIONS: The low prevalence of anti-HAV (IgG) in persons under 25 years old suggest that in the adolescent population the implementation of universal vaccination programs is recommended even without previous serologic screening. Otherwise, the results suggest that HAV prevaccination screening in our geographical were must be limited to subjects older than 25 years.

The role of the nodI and nodJ genes in the transport of Nod metabolites in Rhizobium etli.

A kinetic analysis of secretion of lipo-chitin oligosaccharides (LCO) produced by Rhizobium etli (Re) wild-type (wt) strain and derivatives carrying disrupted nodI or nodJ genes was performed. LCO were detected in the growth media of the wt strain as early as 1 h after nod gene induction. In contrast, strains carrying nodI or nodJ mutations secreted less LCO, and accumulated LCO metabolites intracellularly after 4 h of induction. These Re mutants presented a delayed nodulation phenotype and a reduction in the maximum number of nodules formed in Phaseolus vulgaris roots.

[Serum hepatitis B markers: atypical patterns detected at the Hospital Insular de Gran Canaria]. / Marcadores serológicos de hepatitis B: patrones atípicos detectados en el Hospital Insular de Gran Canaria.

Two atypical serological markers of hepatitis B virus (HBV) infection were detected in 19 patients during a 18-month period study. Pattern 1 (10 patients) was consistent with HBV-2 infection. Reactivity of HbsAG was confirmed by neutralization tests; the absence of other markers was also verified, included anti-HBcIgM. Three of the patients were classified in high risk groups and seven in the low risk groups for hepatitis B; in none of them was co-infection with hepatitis A virus (HAV) detected. Pattern 2 (9 patients) was characterized by the detection of HBsAg and HBeAg and the absence of other hepatitis B markers. Six of these patients were HIV-positive patients and had increased and persistent levels (for longer than 12 weeks) of these markers. In the three remaining patients (with no underlying immunological disorders) there was a loss of these markers within a variable time (2 days to 16 weeks). Nevertheless, DNA-VHB was detected in one of these serum samples once all markers of virus B had disappeared.

The NodL and NodJ proteins from Rhizobium and Bradyrhizobium strains are similar to capsular polysaccharide secretion proteins from gram-negative bacteria.

The NodL and NodJ nodulation proteins have been described in different Rhizobium and Bradyrhizobium species. The nodLJ genes belong to the nod regulon. Other genes from this regulon are involved in the biosynthesis and modification of lipo-oligosaccharide molecule(s) which are morphogenic signals when acting on legume roots. It has been proposed that the NodL and NodJ proteins belong to a bacterial inner membrane transport system of small molecules. Nucleotide sequencing of Mudll PR13 insertions in the nodulation region of the symbiotic plasmid from a Rhizobium leguminosarum bv. phaseoli strain CE3 has revealed the presence of nodL and nodJ-related sequences downstream of nodC. Computer nucleotide sequence analysis of the entire NodL and NodJ sequences from R. leguminosarum bv. viciae and Bradyrhizobium japonicum strains show that both proteins are similar to the KpsT and KpsM proteins from Escherichia coli K1 and K5 strains, to the BexB and BexA proteins from Haemophilis influenzae and to the CtrD and CtrC proteins from Neisseria meningitidis, respectively. Except for the NodL and NodJ proteins, all of them have been involved in the mechanism of secretion of polysaccharides in each of their harbouring species. On the basis of the similarity found, we propose that the NodL and the NodJ proteins could be involved in the export of a lipo-oligosaccharide.