Baroreceptor function during exercise: resetting the record

This paper briefly reviews the historical evolution of ideas about how baroreflexes operate and continue to regulate arterial blood pressure during exercise. Observations from studies conducted in conscious humans and animals are emphasized and three main questions are asked. First, do baroreflexes contribute to arterial blood pressure regulation during exercise? Second, if baroreflexes contribute to blood pressure regulation during exercise, how do they do it? Third, are there any pathophysiological conditions in which manipulation of baroreflexes or baroreflex 'dysfunction' might alter exercise responses? In this context, ideas related to baroreflex resetting during exercise are emphasized, and the potential improvement in exercise tolerance in cardiovascular disease that might be achieved by electrical stimulation of the carotid sinus nerve is highlighted. Additionally, the key contributions of John Shepherd and the late David Donald (along with their colleagues) on related issues are noted.     

Association of benign recurrent vertigo and migraine in 208 patients

The aim of this study was to determine the association of benign recurrent vertigo (BRV) and migraine, using standardized questionnaire-based interview of 208 patients with BRV recruited through a University Neurotology clinic. Of 208 patients with BRV, 180 (87%) met the International Classification of Headache Disorders 2004 criteria for migraine: 112 migraine with aura (62%) and 68 without aura (38%). Twenty-eight (13%) did not meet criteria for migraine. Among patients with migraine, 70% experienced headache, one or more auras, photophobia, or auditory symptoms with some or all of their vertigo attacks, meeting the criteria for definite migrainous vertigo. Thirty per cent never experienced migraine symptoms concurrent with vertigo attacks. These met criteria for probable migrainous vertigo. Among patients without migraine, 21% experienced either photophobia or auditory symptoms with some or all of their vertigo attacks; 79% experienced only isolated vertigo. The age of onset and duration of vertigo attacks did not differ significantly between patients with (34 ± 1.2 years) and patients without migraine (31 ± 3.0 years). In patients with migraine, the age of onset of migraine headache preceded the onset of vertigo attacks by an average of 14 years and aura preceded vertigo by 8 years. The most frequent duration of vertigo attacks was between 1 h and 1 day. Benign recurrent vertigo is highly associated with migraine, but a high proportion of patients with BRV and migraine never have migraine symptoms during their vertigo attacks. Other features such as age of onset and duration of vertigo are similar between patients with or without migraine.     

The effects of intense physical exercise on secondary antibody response in young and old mice

BACKGROUND AND PURPOSE: Based largely on data from young subjects, intense physical exercise is believed to suppress immune function. In addition, immune function, including secondary antibody response, declines with advancing age. Therefore, intense exercise in old subjects may further suppress the secondary antibody response. The purpose of this in vivo study was to investigate the effects of intense physical exercise on secondary antibody response in young (6-8 weeks) and old (22-24 months) C57BL/6 mice. SUBJECTS AND METHODS: Data were obtained from 22 young and 18 old C57BL/6 mice that were immunized to human serum albumin (HSA) and randomly divided into 3 groups. Two groups were exposed to a single bout of intense exercise to exhaustion and immediately boosted with an injection of HSA. The first group did not exercise further, but the second group continued with daily bouts of intense exercise to exhaustion for 9 days. The third group (control group) did not undergo intense exercise, but received the booster injection of HSA at the same time as the other groups. Ten days after the HSA booster injection, when high level of antibodies are produced in secondary antibody response, serum anti-HSA antibodies were measured by enzyme-linked immunosorbent assay. RESULTS: Young mice did not show suppression of secondary antibody response following intense exercise. However, old mice, exposed to a single bout of intense exercise, had an enhanced response similar to the response seen in young control mice. CONCLUSION AND DISCUSSION: The widely accepted hypothesis of immunosuppression resulting from intense exercise may not be true for old mice.     

Granular cell tumor of the larynx: report of two pediatric cases.

Granular cell tumors are uncommon neoplasms of the head and neck that usually involve the tongue. The larynx is an atypical site of involvement in adults and a rare site in children. We report two cases of subglottic granular cell tumors, one in a 10-year-old boy and the other in a 6-year-old girl. Although both were initially misdiagnosed as having asthma, radiologic, laryngoscopic, and histologic evaluation of the obstructions eventually furnished the correct diagnosis. The patients were successfully treated by surgical excision of their subglottic masses. The history, presentation, pathologic findings, management, and prognosis of this rare pediatric laryngeal tumor are explored.     

Diagnosis and treatment of intrapericardial teratoma

Summary Intrapericardial teratoma is a rare mediastinal tumor that originates from aberrant clusters of multipotential cells from three germinal layers. Previous reports have used the combination of cardiac angiography, CT scan, and echocardiogram to establish the diagnosis prior to surgery. We report a case of intrapericardial teratoma diagnosed noninvasively and removed surgically within the first three days of life. Furthermore, we compare the diagnostic accuracy of echocardiography and computerized tomography (CT), and discuss the superiority of noninvasive evaluation in the management of these critically ill infants.     

Differential effects of once-daily antihypertensive drugs on blood pressure,left ventricular mass and sympathetic activity: Nifedipine-GITS versus felodipine-ER versus enalapril

BACKGROUND: Recent meta-analyses suggest that once-daily dihydropyridines and angiotensin-converting enzyme inhibitors cause similar decreases in left ventricular (LV) mass for comparable decreases in blood pressure (BP). However, some dihydropyridines, such as felodipine-extended release (ER), still increase sympathetic activity and may, therefore, be less effective in decreasing LV mass. OBJECTIVES: To evaluate the effects of long term antihypertensive treatment with nifedipine-gastrointestinal therapeutic system (GITS) and felodipine-ER compared with enalapril on LV mass relative to the extent of BP control (assessed by 24 h ambulatory BP monitoring) and sympathetic activity (assessed by plasma catecholamine concentrations). PATIENTS AND METHODS: Enalapril was started at 10 mg/day, felodipine-ER at 5 mg/day and nifedipine-GITS at 30 mg/day, all once daily. Doses were increased to 20 mg/day, 10 mg/day or 60 mg/day, respectively, if the office BP remained 160/90 mmHg or greater at the end of the dosing interval. Evaluable echocardiograms were obtained for 116 patients at the end of the study (30 weeks of treatment). RESULTS: On 24 h ambulatory BP monitoring, nifedipine-GITS caused a consistent decrease in BP throughout the 24 h dosing interval, whereas felodipine-ER caused a more marked fall in BP during the day, and enalapril's effects diminished during the night and had disappeared by the morning. Only felodipine-ER significantly increased supine and standing plasma noradrenaline by more than 50% similarly after six, 18, and 30 weeks of treatment. In BP responders (decrease in systolic BP 10 mmHg or greater), enalapril and nifedipine-GITS caused clear decreases in LV mass by 12 to 16 g/m2, whereas felodipine-ER was less effective (decrease by only 6 g/m2, P<0.01 versus enalapril). CONCLUSIONS: Once-daily dihydropyridines should not be regarded as one homogeneous class and, compared with felodipine-ER, nifedipine-GITS exhibits a better profile regarding 24 h BP control, sympathetic activation and regression of LV mass.     

Are stentless valves hemodynamically superior to stented valves? A prospective randomized trial

BACKGROUND: Although stentless aortic bioprostheses are believed to offer improved outcomes, hemodynamic benefits remain unsubstantiated. METHODS: Fifty-three patients were randomized to receive the stented C-E pericardial valve (CE) and 46 patients the Toronto Stentless Porcine valve (SPV). Annuli were sized for the optimal insertion of both valve types, such that surgeons were required to commit to specific valve sizes before randomization. Echocardiographic measurements and functional status (Duke Activity Status Index) were assessed at 3 and 12 months postoperatively. RESULTS: Although cardiopulmonary bypass times (CE: 118.6+/-36.3 minutes; SPV: 148.5+/-30.9 minutes; p = 0.0001) and aortic cross-clamp times (CE: 95.4+/-28.6 minutes; SPV: 123.6+/-24.1 minutes; p = 0.0001) were significantly prolonged in the SPV group, perioperative morbidity and mortality was similar between groups. Neither valve offered a superior internal diameter for any given annular diameter (mean decrease in left ventricular outflow tract diameter after valvular implantation: SPV: 3.4+/-1.11 mm versus CE: 3.7+/-1.33 mm; p = 0.25). Although labeled mean valve size was significantly larger in the SPV group, the actual mean valve size based on internal valvular diameter was no different between groups (CE: 21.9+/-2.0 mm; SPV: 22.3+/-2.0 mm; p = 0.286). Although effective orifice areas increased, and mean and peak transvalvular gradients decreased in both groups over time, no differences were demonstrated between groups at 12 months. Similarly, although significant regression of left ventricular mass was accomplished in both groups over time, no differences were demonstrated between groups. Finally, Duke Activity Status Index scores of functional status improved in both groups over time; however, no differences were noted between groups at 12 months postoperatively. CONCLUSIONS: Although offering excellent outcomes, stentless valves did not demonstrate superior hemodynamic indices in comparison to stented valves up to 12 months after implantation.