Effects of sidestream cigarette smoke exposure on baroreflex components in spontaneously hypertensive rats

We evaluated short-term effects of sidestream cigarette smoke (SSCS) exposure on baroreflex function in spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) normotensive rats. Rats were exposed to SSCS during three weeks, 180min, five days per week, in a concentration of carbon monoxide (CO) between 100 and 300ppm. We observed that SSCS exposure increased tachycardic peak and heart rate range while it attenuated bradycardic reflex in WKY. In respect to SHR, SSCS also increased tachycardic peak. Taken together, our data suggests that three weeks of exposure to SSCS affects the sympathetic and parasympathetic component of the baroreflex in normotensive WKY while it tended to affect the sympathetic component in SHR.

The presence of a vocal ligament in fetuses: a histochemical and ultrastructural study

Although it is currently believed that the vocal ligament of humans undergoes considerable development postnatally, there is no consensus as to the age at which it first emerges. In the newborn infant, the lamina propria has been described as containing a sparse collection of relatively unorganized fibres. In this study we obtained larynges from autopsy of human fetuses aged 7-9 months and used light and electron microscopy to study the collagenous and elastic system fibres in the lamina propria of the vocal fold. Collagen fibres were viewed using the Picrosirius polarization method and elastic system fibres were stained using Weigert`s resorcin-fuchsin after oxidation with oxone. The histochemical and electron microscopic observations were consistent, showing collagen populations with an asymmetric distribution across different compartments of the lamina propria. In the central region, the collagen appeared as thin, weakly birefringent, greenish fibres when viewed using the Picrosirius polarization method, whereas the superficial and deep regions contained thick collagen fibres that displayed a strong red or yellow birefringence. These findings suggest that the thin fibres in the central region consist mainly of type III collagen, whereas type I collagen predominates in the superficial and deep regions, as has been reported in studies of adult vocal folds. Similarly, elastic system fibres showed a differential distribution throughout the lamina propria. Their distribution pattern was complementary to that of collagen fibres, with a much greater density of elastic fibres apparent in the central region than in the superficial and deep regions. This distribution of collagen and elastic fibres in the fetal vocal fold mirrors that classically described for the adult vocal ligament, suggesting that a vocal ligament has already begun to develop by the time of birth. The apparently high level of organization of connective tissue components in the newborn is in contrast to current hypotheses that argue that the mechanical stimuli of phonation are essential to the determination of the layered structure of the lamina propria and suggests that genetic factors may play a more significant role in the development of the vocal ligament than previously believed.

Ventilation Distribution Studies Comparing Technegas and ""Gallgas"" Using (68)GaCl(3) as the Label

Ventilation distribution can be assessed by SPECT with Technegas. This study was undertaken in piglets with different degrees of ventilation inhomogeneity to compare PET using (68)Ga-labeled pseudogas or ""Gallgas"" with Technegas. Methods: Twelve piglets were studied in 3 groups: control, lobar obstruction, and diffuse airway obstruction. Two more piglets were assessed for lung volume (functional residual capacity). Results: In controls, SPECT and PET images showed an even distribution of radioactivity. With lobar obstruction, the absence of ventilation of the obstructed lobe was visible with both techniques. In diffuse airway obstruction, SPECT images showed an even distribution of radioactivity, and PET images showed more varied radioactivity over the lung. Conclusion: PET provides detailed ventilation distribution images and a better appreciation of ventilation heterogeneity. Gallgas with PET is a promising new diagnostic tool for the assessment of ventilation distribution.

POISSON DISTRIBUTION TO ANALYZE NEAR-THRESHOLD MOTOR EVOKED POTENTIALS

Motor unit action potentials (MUAPs) evoked by repetitive, low-intensity transcranial magnetic stimulation can be modeled as a Poisson process. A mathematical consequence of such a model is that the ratio of the variance to the mean of the amplitudes of motor evoked potentials (MEPs) should provide an estimate of the mean size of the individual MUAPs that summate to generate each MEP. We found that this is, in fact, the case. Our finding thus supports the use of the Poisson distribution to model MEP generation and indicates that this model enables characterization of the motor unit population that contributes to near-threshold MEPs. Muscle Nerve 42: 825-828, 2010

Forefoot Deformity in Diabetic Neuropathic Individuals and its Role in Pressure Distribution and Gait

Background. Foot deformities have been related to diabetic neuropathy progression but their influence on plantar distribution during dynamic tasks is not completely understood. The purpose of the present study was to investigate the influence of metatarsal head prominence and claw toes on regional plantar pressures during gait in patients with diabetic neuropathy Methods Seventy-one adults participated in this study categorized into three groups: a control group (CG, n = 32), patients with diabetic neuropathy without any foot deformities (DG, n = 20), and patients with diabetic neuropathy with metatarsal head prominence and/or claw toes (DMHG, n = 19). Plantar pressure variables (contact area, peak pressure, and maximum mean pressure) were evaluated during gait on rearfoot, midfoot, and forefoot using capacitive insoles (Pedar-X System, Novel Inc., Munich, Germany). A general linear model was applied to repeatedly measure and analyze variance relationships between groups and areas. Results. DMHG. presented larger contact areas at the forefoot and midfoot along with higher peak pressure at the rearfoot compared to the other two groups The DG showed higher mean pressure at the midfoot compared to:the other two groups. Conclusion. The coexistence of diabetic neuropathy and metatarsal head prominence in addition to claw toes, resulted in overloading the rearfoot and enhancing the contact area of forefoot and midfoot while walking. This plantar pressure distribution is a result of a different coordination pattern adopted in order to reduce plantar loads at the anterior parts of the foot that were structurally altered. Patients with diabetic neuropathy without any forefoot deformities presented a different plantar pressure distribution than patients with deformities suggesting that both neuropathy and structural foot alterations can influence foot rollover mechanisms.

Perfectionism and sensory phenomena: phenotypic components of obsessive-compulsive disorder

Background: The aim of the study was to investigate how perfectionism and sensory phenomena (SP) interact as possible phenotypic components of obsessive-compulsive disorder (OCD). Methods: Forty-seven adult outpatients, meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for OCD, and a control group of 41 community subjects were assessed using the Frost Multidimensional Perfectionism Scale (FM PS), the University of Sao Paulo-Sensory Phenomena Scale, and other standard measures of OCD severity. Results: Three of the FMPS subscales (""concern over mistakes,"" ""doubts about action,"" and ""parental criticism"") were significantly different between OCD patients and control subjects. All subtypes of SP were significantly more frequent and more severe in OCD than in control subjects. The ""incompleteness"" subtype of SP was associated with high scores on all dimensions of the FMPS, whereas the ""just-right"" subtype of SP was only associated with ""doubts about action,"" ""personal standards,"" and ""organization"" subscales of the FMPS. Conclusions: Presence and severity of SP and specific elements of perfectionism clearly distinguish OCD patients from healthy control subjects. Some SP subtypes are associated with specific FPMS subscale scores, whereas others are not. These results emphasize the relevance of assessing different subtypes of perfectionism and SP in OCD patients as important subcomponents of the OCD phenotype. (C) 2009 Elsevier Inc. All rights reserved.

Initial hepatosplanchnic blood flow distribution and oxygen metabolism in experimental model of hypotensive brain death

Background: Organs from the so-called marginal donors have been used with a significant higher risk of primary non function than organs retrieved from the optimal donors. We investigated the early metabolic changes and blood flow redistribution in splanchnic territory in an experimental model that mimics marginal brain-dead (BD) donor. Material/Methods: Ten dogs (21.3 +/- 0.9 kg), were subjected to a brain death protocol induced by subdural balloon inflation and observed for 30 min thereafter without ally additional interventions. Mean arterial and intracranial pressures, heart rate, cardiac output (CO), portal vein and hepatic artery blood flows (PVBF and HABF, ultrasonic flowprobe), and O(2)-derived variables were evaluated. Results: An increase in arterial pressure, CO, PVBF and HABF was observed after BD induction. At the end, an intense hypotension with normalization in CO (3.0 +/- 0.2 VS. 2.8 +/- 2.8 L/min) and PVBF (687 +/- 114 vs. 623 +/- 130 ml/min) was observed, whereas HABF (277 33 vs. 134 28 ml/min, p<0.005) remained lower than baseline values. Conclusions: Despite severe hypotension induced by sudden increase of intracranial pressure, the systemic and splanchnic blood flows were partially preserved without signs of severe hypoperfusion (i.e. hyperlactatemia). Additionally, the HABF was mostly negatively affected in this model of marginal BD donor. Our data suggest that not only the cardiac output, but the intrinsic hepatic microcirculatory mechanism plays a role in the hepatic blood flow control after BD.

Benzylglucosinolate, Benzylisothiocyanate, and Myrosinase Activity in Papaya Fruit during Development and Ripening

Papaya is a climacteric fruit that has high amounts of benzylglucosinolates (BG) and benzylisothiocyanates (BITC), but information regarding levels of BG or BITC during fruit development and ripening is limited. Because BG and BITC are compounds of importance from both a nutritional and a crop yield standpoint, the aim of this work was to access data on the distribution and changes of BG and BITC levels during fruit development and ripening. BG and BITC levels were quantified in peel, pulp, and seeds of papaya fruit. Volatile BITC was also verified in the internal cavity of the fruit during ripening. The influence of the ethylene in BG and BITC levels and mirosinase activity was tested by exposing mature green fruits to ethylene and 1-methylcyclopropene (1-MCP). The highest BG levels were detected in seeds, followed by the peel and pulp being decreased in all tissues during fruit development. Similarly, the levels of BITC were much higher in the seeds than the peel and pulp. The levels of BG for control and ethylene-treated fruit were very similar, increasing in the pulp and peel during late ripening but not changing significantly in seeds. On the other hand, fruit exposed to 1-MCP showed a decrease in BG amount in the pulp and accumulation in seed. The treatments did not result in clear differences regarding the amount of BITC in the pulp and peel of the fruit. According to the results, ethylene does not have a clear effect on BITC accumulation in ripening papaya fruit. The fact that BG levels in the pulp did not decrease during ripening, regardless of the treatment employed, and that papaya is consumed mainly as fresh fruit, speaks in favor of this fruit as a good dietary source for glucosinolate and isothiocyanates.

Changes in slow and fast alpha bands in subjects submitted to different amounts of functional electrostimulation

Objective: To examine the changes in slow (8-10 Hz)and fast (10-12 Hz) alpha bands of EEG in three groups of subjects submitted to different amounts of functional electrostimulation (FES). Our hypothesis is that different amounts of electrostimulation may cause different patterns of activation in the sensorimotor cortex. In particular, we expect to see an increase in alpha power due to habituation effects. We examine the two bands comprised by alpha rhythm (i.e., slow and fast alpha), since these two sub-rhythms are related to distinct aspects: general energy demands and specific motor aspects, respectively. Methods: The sample was composed of 27 students, both sexes, aging between 25 and 40 years old. The subjects were randomly distributed in three groups: control (n = 9), G24 (n = 9) and G36 (n = 9). A FES equipment (Neuro Compact-2462) was used to stimulate the right index finger extension. Simultaneously, the electroencephalographic signal was acquired. We investigated the absolute power in slow and fast alpha bands in the sensorimotor cortex. Results: The G36 indicated a significant increasing in absolute power values in lower and higher alpha components, respectively, when compared with the control group. Particularly, in the following regions: pre-motor cortex and primary motor cortex. Discussion: FES seems to promote cortical adaptations that are similar to those observed when someone learns a procedural task. FES application in the G36 was more effective in promoting such neural changes. The lower and higher components of alpha rhythms behave differently in their topographical distribution during FES application. These results suggest a somatotopic organization in primary motor cortex which can be represented by the fast alpha component. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Capnography reflects ventilation/perfusion distribution in a model of acute lung injury

Background Changes in the shape of the capnogram may reflect changes in lung physiology. We studied the effect of different ventilation/perfusion ratios (V/Q) induced by positive end-expiratory pressures (PEEP) and lung recruitment on phase III slope (S(III)) of volumetric capnograms. Methods Seven lung-lavaged pigs received volume control ventilation at tidal volumes of 6 ml/kg. After a lung recruitment maneuver, open-lung PEEP (OL-PEEP) was defined at 2 cmH(2)O above the PEEP at the onset of lung collapse as identified by the maximum respiratory compliance during a decremental PEEP trial. Thereafter, six distinct PEEP levels either at OL-PEEP, 4 cmH(2)O above or below this level were applied in a random order, either with or without a prior lung recruitment maneuver. Ventilation-perfusion distribution (using multiple inert gas elimination technique), hemodynamics, blood gases and volumetric capnography data were recorded at the end of each condition (minute 40). Results S(III) showed the lowest value whenever lung recruitment and OL-PEEP were jointly applied and was associated with the lowest dispersion of ventilation and perfusion (Disp(R-E)), the lowest ratio of alveolar dead space to alveolar tidal volume (VD(alv)/VT(alv)) and the lowest difference between arterial and end-tidal pCO(2) (Pa-ETCO(2)). Spearman`s rank correlations between S(III) and Disp(R-E) showed a =0.85 with 95% CI for (Fisher`s Z-transformation) of 0.74-0.91, P < 0.0001. Conclusion In this experimental model of lung injury, changes in the phase III slope of the capnograms were directly correlated with the degree of ventilation/perfusion dispersion.