Evidence that blood pressure remains under the control of arterial baroreceptors in renal hypertensive rats

The purpose of the present study was to determine the range of the influence of the baroreflex on blood pressure in chronic renal hypertensive rats. Supramaximal electrical stimulation of the aortic depressor nerve and section of the baroreceptor nerves (sinoaortic denervation) were used to obtain a global analysis of the baroreceptor-sympathetic reflex in normotensive control and in chronic (2 months) 1-kidney, 1-clip hypertensive rats. The fall in blood pressure produced by electrical baroreceptor stimulation was greater in renal hypertensive rats than in normotensive controls (right nerve: -47 ± 8 vs -23 ± 4 mmHg; left nerve: -51 ± 7 vs -30 ± 4 mmHg; and both right and left nerves: -50 ± 8 vs -30 ± 4 mmHg; P < 0.05). Furthermore, the increase in blood pressure level produced by baroreceptor denervation in chronic renal hypertensive rats was similar to that observed in control animals 2-5 h (control: 163 ± 5 vs 121 ± 1 mmHg; 1K-1C: 203 ± 7 vs 170 ± 5 mmHg; P < 0.05) and 24 h (control: 149 ± 3 vs 121 ± 1 mmHg; 1K-1C: 198 ± 8 vs 170 ± 5 mmHg; P < 0.05) after sinoaortic denervation. Taken together, these data indicate that the central and peripheral components of the baroreflex are acting efficiently at higher arterial pressure in renal hypertensive rats when the aortic nerve is maximally stimulated or the activity is abolished.

Velocardiofacial syndrome with facial and pinna asymmetries.

This study reports some of the most important clinical features of the velocardiofacial syndrome (hypoplastic zygomatic arch, prominent nose with square nasal root, bilateral epicanthus, downslanting palpebral fissures, and learning disabilities) in a Brazilian boy presenting face and pinna asymmetries. These findings may facilitate the diagnosis of this syndrome.

Velocardiofacial syndrome with facial and pinna asymmetries

This study reports some of the most important clinical features of the velocardiofacial syndrome (hypoplastic zygomatic arch, prominent nose with square nasal root, bilateral epicanthus, downslanting palpebral fissures, and learning disabilities) in a Brazilian boy presenting face and pinna asymmetries. These findings may facilitate the diagnosis of this syndrome.

Electromyographic analysis of lip muscle function in operated cleft subjects.

EMG activity of the upper lip was measured with bipolar surface electrodes during speech and nonspeech tasks in order to assess labial function in subjects with repaired clefts. Eighteen patients between 15 and 23 years of age with repaired unilateral cleft lip (isolated or combined with repaired cleft palate) were compared to 24 matched noncleft subjects. Data analysis demonstrated that the amplitude of action potentials of the upper lip was significantly greater in the cleft group. We hypothesize that the enhanced activity of the repaired upper lip during function may contribute to the facial growth abnormalities usually seen in the cleft population.

Pulmonary function of individuals with congenital cleft palate.

Ventilatory pulmonary function was investigated in 160 children and adults with repaired or unrepaired congenital cleft palate in comparison with 130 normal children and adults. Pulmonary function tests included measurement of lung volumes, of maximal voluntary ventilation (MVV) and of forced spirometry parameters: forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio and mean forced expiratory flow during the middle half of FVC (FEF25-75). Patients with cleft palate demonstrated significant differences from normal individuals in some of the measurements made. Functional alterations were observed at higher frequency among adult patients with unrepaired clefts and mainly consisted of a reduction in expiratory flows and MVV. However, the deviations observed were usually discrete and probably of low physiopathologic significance. The results permit us to conclude that, in contrast to data reported by others, subjects with congenital cleft palate have little impairment of pulmonary ventilatory function.

[Electrolyte secretion in saliva]. / A secreção eletrolítica da saliva.

Because they are easily accessible and because their secretion can be obtained in an almost pure form, the salivary glands are an adequate model for the study of hydroelectrolytic secretion of secreting epithelia which cannot generate an action potential. It is generally accepted that the salivary secretion occurs in two stages: in the acini, where primary saliva is formed similar in ionic constituents to plasmatic water, and in the ducts of the adenomer, where such original saliva is modified by absorption and secretion of electrolytes. Departing from Thaysen's hypothesis, the mechanisms responsible for the preparation of final saliva are reviewed. The authors briefly discuss the evolution of the ideas about salivary secretion emphasizing recent works which modified early theories, particularly the role of the Na-K ATPase and the cotransportation of the Cl- ion. Ideas about what occurs along the ducts are also reviewed, starting with the hypothesis of Brusilow and Cook, which was later on gradually modified. Recent works are compared to those of the authors. Certain topics, such as the impermeability of duct walls to water, existence of a threshold for the transport of Na+, possibility of experimentally obtaining saliva with higher osmotic pressure than plasma are stressed. Finally, the role of loop diuretics which interfere in potassium transport channels is discussed.

Masseteric electromyographic silent period duration in patients with temporomandibular joint dysfunction

The present study compared the duration of the electromyographic silent period (SP) of the masseter muscles elicited by chin-tapping in normal asymptomatic adults (N=39) and in a group with sympstoms of temporomandibular joint dysfunction (TMJD)(N=3).EMG activity was recorded from right (RM) and left (LM) masseter muscles using bipolar surface electrodes coupled to a DISA 1500 EMG-system.During maximal clenching, ten taps were applied downwards to the chin with a reflex hammer. The mean SP durations obtained for the normal group were 25.45ñ4.20 ms (RM) and 25.33ñ4.18ms (LM), whereas the TMJD group presented significantly greater values (P<0.01,Student t-test) of 41.89ñ12.94ms (RM) and 42.40ñ12.99ms (LM).The upper limits of normality calculated for RM and LM were 32.36 ms and 31.21 ms, respectively. Eighty-four percent of patients with TMJD showed SP durations above these limits. The results indicate that the measurement of masseteric SP duration may be used as an objective diagnostic method of TMJ disorders, provided that borderline values are interpreted with caution along with clinical impressions

Masseteric electromyographic silent period duration in patients with temporomandibular joint dysfunction.

1. The present study compared the duration of the electromyographic silent period (SP) of the masseter muscles elicited by chin-tapping in normal asymptomatic adults (N = 39) and in a group with symptoms of temporomandibular joint dysfunction (TMJD) (N = 31). 2. EMG activity was recorded from right (RM) and left (LM) masseter muscles using bipolar surface electrodes coupled to a DISA 1500 EMG-System. During maximal clenching, ten taps were applied downwards to the chin with a reflex hammer. 3. The mean SP durations obtained for the normal group were 25.45 +/- 4.20 ms (RM) and 25.33 +/- 4.18 ms (LM), whereas the TMJD group presented significantly greater values (P less than 0.01, Student t-test) of 41.89 +/- 12.94 ms (RM) and 42.40 +/- 12.99 ms (LM). The upper limits of normality calculated for RM and LM were 32.36 ms and 31.21 ms, respectively. Eighty-four percent of patients with TMJD showed SP durations above these limits. 4. The results indicate that the measurement of masseteric SP duration may be used as an objective diagnostic method of TMJ disorders, provided that borderline values are interpreted with caution along with clinical impressions.

Consonantal intraoral air pressure characteristics in Brazilian postoperative cleft palate speakers with velopharyngeal disorders

1. In the present study we measured intraoral air pressure (Po) during the production of the stop consonant/p/, in a syllabic contes, in normal and surgically repaired cleft palate subjects. po was measured by placing a sensing catheter between the lips in the oral cavity. The catheter was connected to a pressure transducer and the output signals were amplified and transmitted to a recorder. 2. When compared to normal individuals, cleft patients with velopharyngeal insufficiency (VPI) and oral articulation for/p/presented significantly lower Po levels (P<0.01) but pressure curves of normal shape. 3. In cleft palate patients with VPI and glottal coarticulation for/p/, Po was absent or markedly reduced; in the latter case, the Po curve was of a characteristically irregular shape. 4. These results suggest thata measurement of Po during the production of a selected consonant appears to be a suitable instrumental method for identifying VPI and discrininating an oral stop from the compensatory glottal stop often observed in postoperative cleft palate speakers

[Role of the atria in controlling body fluids]. / Papel dos átrios no controle dos fluidos corpóreos.

The atria play a major role in the regulation of body fluids. Since the work of Henry and col., techniques of atrial distention have shown the existence of volume receptors which perceive the fulness of blood volume, the left atrium in particular. When blood volume increases, receptors originate a neuro-humoral reflex in which the afferent path would be the vagus nerve, the hypotalamus would be the center, and the efferent path would be the inhibition of the hypophysis ADH secretion, provoking a decreased water reabsorption and, consequently, diuresis. This mechanism would have precedence over the osmotic regulation. Added to the investigations of the authors, these experiments also point to an increased sodium excretion, for which release of a natriuretic factor in a non-determined site was claimed as responsible. In 1981, de Bold and col. reported a hormone produced in atrial cardiocites (ANF) that would be released upon stretching of the atrium and that would act upon the nephron through different mechanisms to cause deep diuresis and natriuresis. This publication gave origin to numerous investigations. The formula of the responsible peptide was determined. The hormone was sinthesized and the pharmaceutical industry launched many synthetic products. The physiologic and physiopathologic implications of this discovery and the therapeutic potential of these synthetic derivatives are discussed.

Consonantal intraoral air pressure characteristics in Brazilian postoperative cleft palate speakers with velopharyngeal disorders.

1. In the present study we measured intraoral air pressure (Po) during the production of the stop consonant /p/, in a syllabic contex, in normal and surgically repaired cleft palate subjects. Po was measured by placing a sensing catheter between the lips in the oral cavity. The catheter was connected to a pressure transducer and the output signals were amplified and transmitted to a recorder. 2. When compared to normal individuals, cleft palate patients with velopharyngeal insufficiency (VPI) and oral articulation for /p/ presented significantly lower Po levels (P less than 0.01) but pressure curves of normal shape. 3. In cleft palate patients with VPI and glottal coarticulation for /p/, Po was absent or markedly reduced; in the latter case, the Po curve was of a characteristically irregular shape. 4. These results suggest that measurement of Po during the production of a selected consonant appears to be a suitable instrumental method for identifying VPI and discriminating an oral stop from the compensatory glottal stop often observed in postoperative cleft palate speakers.