The Nasal Microbiome in ANCA-Associated Vasculitis: Picking the Nose for Clues on Disease Pathogenesis

PURPOSE OF REVIEW

The onset and progression of small vessel vasculitis associated with anti-neutrophil cytoplasmic antibodies has been linked to microbial infections. Here, we provide a brief overview of the association of nasal colonization of Staphylococcus aureus with ANCA-associated vasculitis (AAV) and discuss several recent studies mapping the nasal microbiome in AAV patients in particular.

RECENT FINDINGS

Nasal microbiome studies revealed dysbiosis as a common trait in active AAV which tends to normalize upon immunosuppressive treatment and quiescent disease. However, due to differences in study design, patient selection, and methodology, the reported microbiome profiles differ considerably precluding conclusions on causal relationships. The microbiome is an emerging area of research in AAV warranting further investigation. Ideally, such studies should be combined with mechanistic studies to unravel key elements related to host-microbe interactions and their relevance for AAV pathogenesis.

Early Conversion From Calcineurin Inhibitor- to Everolimus-Based Therapy Following Kidney Transplantation: Results of the Randomized ELEVATE Trial

In a 24-month, multicenter, open-label, randomized trial, 715 de novo kidney transplant recipients were randomized at 10-14 weeks to convert to everolimus (n = 359) or remain on standard calcineurin inhibitor (CNI) therapy (n = 356; 231 tacrolimus; 125 cyclosporine), all with mycophenolic acid and steroids. The primary endpoint, change in estimated glomerular filtration rate (eGFR) from randomization to month 12, was similar for everolimus versus CNI: mean (standard error) 0.3(1.5) mL/min/1.73² versus -1.5(1.5) mL/min/1.73² (p = 0.116). Biopsy-proven acute rejection (BPAR) at month 12 was more frequent under everolimus versus CNI overall (9.7% vs. 4.8%, p = 0.014) and versus tacrolimus-treated patients (2.6%, p < 0.001) but similar to cyclosporine-treated patients (8.8%, p = 0.755). Reporting on de novo donor-specific antibodies (DSA) was limited but suggested more frequent anti-HLA Class I DSA under everolimus. Change in left ventricular mass index was similar. Discontinuation due to adverse events was more frequent with everolimus (23.6%) versus CNI (8.4%). In conclusion, conversion to everolimus at 10-14 weeks posttransplant was associated with renal function similar to that with standard therapy overall. Rates of BPAR were low in all groups, but lower with tacrolimus than everolimus.

Early Conversion to Prednisolone/Everolimus as an Alternative Weaning Regimen Associates With Beneficial Renal Transplant Histology and Function: The Randomized-Controlled MECANO Trial

In renal transplantation, use of calcineurin inhibitors (CNIs) is associated with nephrotoxicity and immunosuppression with malignancies and infections. This trial aimed to minimize CNI exposure and total immunosuppression while maintaining efficacy. We performed a randomized controlled, open-label multicenter trial with early cyclosporine A (CsA) elimination. Patients started with basiliximab, prednisolone (P), mycophenolate sodium (MPS), and CsA. At 6 months, immunosuppression was tapered to P/CsA, P/MPS, or P/everolimus (EVL). Primary outcomes were renal fibrosis and inflammation. Secondary outcomes were estimated glomerular filtration rate (eGFR) and incidence of rejection at 24 months. The P/MPS arm was prematurely halted. The trial continued with P/CsA (N = 89) and P/EVL (N = 96). Interstitial fibrosis and inflammation were significantly decreased and the eGFR was significantly higher in the P/EVL arm. Cumulative rejection rates were 13% (P/EVL) and 19% (P/CsA), (p = 0.08). A post hoc analysis of HLA and donor-specific antibodies at 1 year after transplantation revealed no differences. An individualized immunosuppressive strategy of early CNI elimination to dual therapy with everolimus was associated with decreased allograft fibrosis, preserved allograft function, and good efficacy, but also with more serious adverse events and discontinuation. This can be a valuable alternative regimen in patients suffering from CNI toxicity.

Linear structures in the core of the Coma cluster of galaxies

The hot x-ray-emitting plasma in galaxy clusters is predicted to have turbulent motion, which can contribute around 10% of the cluster's central energy density. We report deep Chandra X-ray Observatory observations of the Coma cluster core, showing the presence of quasi-linear high-density arms spanning 150 kiloparsecs, consisting of low-entropy material that was probably stripped from merging subclusters. Two appear to be connected with a subgroup of galaxies at a 650-kiloparsec radius that is merging into the cluster, implying coherence over several hundred million years. Such a long lifetime implies that strong isotropic turbulence and conduction are suppressed in the core, despite the unrelaxed state of the cluster. Magnetic fields are presumably responsible. The structures seen in Coma present insight into the past billion years of subcluster merger activity.

Accelerated atherosclerosis in patients with Wegener's granulomatosis

BACKGROUND

Several autoimmune disorders are complicated by excess cardiovascular disease. In addition to traditional risk factors, non-traditional risk factors such as endothelial activation and excessive vascular remodelling might be determinants of the progression of atherosclerosis in patients with an autoimmune disease.

OBJECTIVE

To evaluate whether patients with Wegener's granulomatosis (WG) have an increased prevalence of atherosclerosis and to determine predisposing factors.

METHODS

29 WG patients (19 men; mean (SD) age, 53 (14) years) with inactive disease and 26 controls (16 men; age 53 (15) years) were studied. Common carotid intima-media thickness (IMT) was measured by ultrasound. In all individuals traditional risk factors for cardiovascular disease were determined. High sensitivity C reactive protein (hsCRP) was measured. Endothelial activation was assessed by measuring thrombomodulin, vascular cell adhesion molecule-1, and von Willebrand factor. As a marker of vascular remodelling matrix metalloproteinases (MMP-3 and MMP-9) and TIMP-1 were measured.

RESULTS

IMT was increased in WG patients compared with controls (p<0.05). No differences in traditional risk factors and endothelial activation markers between patients and controls were found. Levels of hsCRP, MMPs, and TIMP-1 were increased in WG patients (p<0.05).

CONCLUSIONS

Increased IMT found in WG patients cannot be explained by an increased prevalence of traditional risk factors. Although endothelial activation markers in WG patients with inactive disease were not increased, the raised levels of hsCRP, MMPs, and TIMP-1 suggest that enhanced inflammation and excessive vascular remodelling are contributing factors in the development of accelerated atherosclerosis in WG.

Deoxyribonucleic acid flow cytometry and traditional pathologic variables in invasive penile carcinoma: assessment of prognostic significance

OBJECTIVES

The identification of reliable prognostic factors to guide the selection of patients at high risk of harboring subclinical metastases in penile cancer is important. We evaluated traditional pathologic variables and deoxyribonucleic acid (DNA) flow cytometry to determine the prognostic significance of these variables for the subsequent development of lymph node metastases.

METHODS

Clinical data and pathologic specimens were retrospectively reviewed from patients treated surgically at university-affiliated hospitals from 1958 to 1987. Pathologic analysis (grade, depth of invasion, and pathologic stage) and DNA flow cytometry were performed on specimens from 46 patients with invasive penile carcinoma and complete medical records. Pathologic variables were compared with DNA flow cytometry results in patients who never developed lymph node metastasis (32 patients, median follow-up 121 months) and in those who presented with or developed proved lymph node metastases (14 patients, median follow-up 18 months).

RESULTS

The distributions of diploid and nondiploid tumors were similar in patients with or without lymph node metastasis. In addition, there was no significant difference in the grade distributions of tumors with respect to lymph node status. Patients with positive nodes more commonly had tumors that invaded greater than 0.5 cm or that exhibited pathologic Stage T2 or greater (deep invasion). All 14 patients who presented with or subsequently developed metastasis had deep primary tumors. Thirteen of 36 patients with clinically negative nodes had superficially invasive tumors (pathologic Stage T1 and depth of invasion 0.5 cm or less), and none developed metastasis (median follow-up 124 months [range 58 to 240]). Tumor grade was significantly related to the likelihood of deep invasion but was not an independent prognostic factor for metastasis.

CONCLUSIONS

DNA flow cytometry does not add prognostic information to that obtained by pathologic assessment in patients with invasive penile carcinoma. The presence of pathologic Stage T2 or greater or depth of invasion greater than 0.5 cm defines a group of patients at high risk of inguinal node metastasis. A novel finding was that patients with minimally invasive lesions (0.5 cm or less) and no evidence of corporal invasion (pathologic Stage T1) have little risk of inguinal node metastasis. Close observation of reliable patients meeting these criteria may be a safe alternative to prophylactic lymphadenectomy.

Diagnostic yield of repeated transrectal ultrasound-guided biopsies stratified by specific histopathologic diagnoses and prostate specific antigen levels

OBJECTIVES

To determine the diagnostic yield of secondary and tertiary transrectal ultrasound (TRUS)-guided biopsies of the prostate in men suspected of having carcinoma of the prostate because of an elevated serum prostate-specific antigen (PSA) level or an abnormal digital rectal examination (DRE).

METHODS

The pathology database at the Dallas Veterans Affairs Medical Center was retrospectively searched for patients who had undergone at least two TRUS-guided biopsies of the prostate within a 6-month time span. Pertinent demographic data, serum PSA, outcomes of the two (or more) biopsies stratified in six distinct histopathologic diagnoses, and Gleason grade if carcinoma of the prostate was identified, were entered into a database and analyzed.

RESULTS

A total of 123 men had at least two TRUS-guided biopsies, of which 22 had three biopsies. Mean age of this group was 68.5 +/- 0.51 (SE), and mean PSA was 11.5 +/- 1.07 (SE). Of 123 patients, 28 had a positive second biopsy following a negative first biopsy, for a positive biopsy rate of 23%. Only 2 of 22 patients who underwent a third biopsy were found to have carcinoma of the prostate, for a positive biopsy rate of 9%. The positive biopsy rate for the second biopsy was 19% (3 of 16) if the PSA was 4.0 ng/mL or less, 15% (10 of 66) if the PSA was between 4 and 10.0 ng/mL independent of the DRE findings, and 37% (15 of 41) if the PSA was 10.0 ng/mL or higher. Benign prostatic hyperplasia (59 of 123 [48%]) and atypia (38 of 123 [31%]) were the most common histopathologic diagnoses on the first biopsy, and the positive re-biopsy rates were similar for these two groups (25% versus 21 %).

CONCLUSIONS

An overall positive biopsy rate of 23% in our retrospective series of 123 men with a mean PSA of 11.5 ng/mL warrants the performance of a second biopsy independent of the histopathologic diagnosis made on the first (negative) biopsy, if the outcome of such biopsy would have therapeutic consequences for the patient. This policy should not be restricted to men with a PSA above the cutoff level of 4.0 ng/mL alone. Patients with atypia should be pursued aggressively, as even on a third biopsy the positive biopsy rate was 29%.

Comparison of continuous and discrete frequency-versus-radius frequency-modulated reticles

We present a general expression for the transmission function of the discrete frequency-versus-radius reticle and compare such a reticle with the more common continuous reticle. A discrete form of the frequency-versus-radius reticle has an integer number of chopping cycles on a single radius. The discreteform limits the resolution of the reticle in the radial direction, but this limit is not severe for small-target images. However, since no phase reversal occurs, electronic processing is simplified.

Clinical and hemodynamic correlates of sympathetic nerve activity in normal humans and patients with heart failure: evidence from direct microneurographic recordings

To characterize the neural excitatory state of heart failure, simultaneous measurements of efferent sympathetic nerve activity to muscle (by microneurography) and rest hemodynamics were obtained in 10 normal subjects (age 25 +/- 2 years, mean +/- SEM) and 29 patients with heart failure (age 49 +/- 2 years; New York Heart Association functional class II to IV; left ventricular ejection fraction 21 +/- 1%; cardiac index = 2.16 +/- 0.13 liters/min per m2; pulmonary capillary wedge pressure 23 +/- 2 mm Hg). Sympathetic nerve activity was significantly higher in the patients with heart failure (54.7 +/- 4.5 bursts/min) than in normal subjects (16.7 +/- 2.2 bursts/min, p less than 0.001). Multiple linear regression analyses indicated that sympathetic activity in these human subjects was most strongly and inversely correlated with left ventricular stroke work index (r = -0.86, p less than 0.0001) and stroke volume index (r = -0.85, p less than 0.0001). There was a strong positive correlation between sympathetic nerve activity and pulmonary artery diastolic (r = 0.82, p less than 0.0001) and mean (r = 0.81, p less than 0.0001) pressures. Similar correlations were seen when patients with heart failure were analyzed separately. There was no significant correlation between sympathetic nerve activity and mean arterial pressure, left ventricular ejection fraction (by radionuclide ventriculography), cardiac chamber size (by echocardiography) or arterial oxygen tension in the patients with heart failure. Direct measurements of sympathetic nerve activity correlated closely with plasma norepinephrine (r = 0.72, p less than 0.0001) in patients with heart failure. Thus, sympathetic nerve activity at rest parallels impairment of cardiac performance in patients with heart failure.

Pathophysiologic levels of atrial natriuretic factor do not alter reflex sympathetic control: direct evidence from microneurographic studies in humans

To determine if circulating levels of atrial natriuretic factor comparable with those seen in pathophysiologic states alter autonomic control of the circulation, direct recordings of hemodynamic variables and efferent sympathetic nerve activity to muscle (microneurography) were obtained during two separate protocols in a total of 21 normal men (age 25 +/- 1 years). In protocol 1, the responses of 10 men were compared during incremental mechanical unloading of cardiopulmonary baroreceptors with lower body negative pressure versus responses to comparable unloading during infusion of alpha-human atrial natriuretic factor. Lower body negative pressure decreased pulmonary artery diastolic and right atrial pressures, did not alter arterial pressure or heart rate and increased muscle sympathetic nerve activity from 205.2 +/- 36.3 to 438.7 +/- 100.2 units/min (p less than 0.01). Intravenous infusion of atrial natriuretic factor (25 ng/kg per min) increased plasma levels of the hormone from 24 +/- 4 to 322 +/- 34 pg/ml (p less than 0.01, n = 6), produced similar decreases in pulmonary artery diastolic and right atrial pressures, did not alter arterial pressure, increased heart rate and increased sympathetic nerve activity from 233.1 +/- 35.6 to 387.2 +/- 64.9 units/min (p less than 0.05). Thus, during similar hemodynamic perturbations produced by lower body negative pressure or infusion of atrial natriuretic factor at the dose used in this study, these subjects exhibited comparable sympathoexcitatory responses, with a 109 +/- 23% increase in sympathetic activity during lower body negative pressure and a 76 +/- 19% increase during atrial natriuretic factor infusion (p = NS). In protocol 2, the responses of 11 additional men were examined during lower body negative pressure performed before and again during infusion of atrial natriuretic factor (12.5 ng/kg per min). During baseline (prehormone) trials, lower body negative pressure (-14.5 +/- 1.6 mm Hg) decreased central venous pressure, did not change arterial pressure or heart rate and increased sympathetic nerve activity from 215 +/- 47.7 to 372.3 +/- 64.3 units/min (p less than 0.001). Infusion of atrial natriuretic factor increased plasma levels of the hormone from 39 +/- 8 to 313 +/- 18 pg/ml (p less than 0.01, n = 7); central venous pressure was held constant during hormone infusion by intravenous infusion of saline solution.(ABSTRACT TRUNCATED AT 400 WORDS)

Sympathoinhibitory responses to digitalis glycosides in heart failure patients. Direct evidence from sympathetic neural recordings

Digitalis glycosides exert both excitatory and inhibitory autonomic actions in animals and produce vasoconstriction in normal humans but produce vasodilation in heart failure patients. To determine whether or not these contrasting vascular responses are due to differing autonomic actions of the drug, we compared the responses to intravenous administration of Cedilanid-D (0.02 mg/kg) in eight normal subjects (mean age, 23 +/- 1 years) and eight patients with moderate-to-severe heart failure (mean age, 52 +/- 5 years, NYHA Class III-IV). Hemodynamics and efferent sympathetic nerve activity to muscle (MSNA) were measured during 5-minute periods before (control) and 20 minutes after drug administration. In the heart failure patients, Cedilanid-D significantly increased systolic and pulse pressures, whereas mean arterial pressure was unchanged. There was a decrease in right atrial pressure and a tendency for a decrease in pulmonary artery diastolic pressure with a slowing of heart rate. Cardiac index increased by 24 +/- 7%. Short-term administration of digitalis in these heart failure patients produced a fall in forearm vascular resistance (from 37.6 +/- 8.2 to 31.8 +/- 8.1 units, p less than 0.05) and an early, profound, and sustained decrease in MSNA (from 831.0 +/- 118.4 to 474.4 +/- 103.6 units/100 heart beats, p less than 0.01). Digitalis glycosides produced different vascular and MSNA responses in the normal subjects. In the normal volunteers, the drug significantly increased systolic, mean, and pulse pressures and decreased central venous pressure and heart rate. Despite the significant increase in arterial pressure, there was no change in forearm vascular resistance (from 11.7 +/- 1.0 to 12.7 +/- 1.0 units, p = NS) or MSNA (from 494.8 +/- 88.5 to 369.1 +/- 60.5 units/100 heart beats, p = NS), suggesting a sympathoexcitatory response in normal subjects. To determine whether or not the digitalis-induced sympathoinhibition in the heart failure patients was simply due to an inotropic effect (stimulation of inhibitory cardiac mechanoreceptors), we studied the responses of seven additional patients with heart failure before and during administration of dobutamine (3.4 +/- 0.4 micrograms/kg/min). Dobutamine produced a 34 +/- 3% increase in cardiac index, no significant change in systemic arterial pressures, a decrease in pulmonary artery diastolic and right atrial pressures, and no change in heart rate or forearm vascular resistance (from 30.2 +/- 4.3 to 26.5 +/- 4.7 units, p = NS).(ABSTRACT TRUNCATED AT 400 WORDS)

Evidence for cholinergically mediated vasodilation at the beginning of isometric exercise in humans

Vasodilation occurs in the nonexercising forearm at the beginning of isometric handgrip despite activation of sympathetic vasoconstrictor reflexes. The mechanism of this response remains unclear. In 33 normal humans, age 24 +/- 1 years (mean +/- SEM), we measured mean arterial pressure, heart rate, and forearm blood flow (plethysmography) in the nonexercising arm during sustained contralateral isometric handgrip at 30% maximal voluntary contraction. Sympathetic nerve activity to calf muscles (microneurography) was also measured in 15 subjects. Handgrip resulted in increases in arterial pressure from 86 +/- 2 to 97 +/- 3 mm Hg (p less than 0.05). Despite increases in nerve activity to calf muscles from 229 +/- 43 to 337 +/- 66 units (p less than 0.005), which would be expected to produce forearm vasoconstriction, forearm vascular resistance in the contralateral resting arm decreased from 20 +/- 3 to 18 +/- 2 units (p less than 0.05). To determine the mechanism of this vasodilatory influence, additional studies were performed with regional autonomic blockade with intra-arterial administration of atropine (0.8 mg, 10 subjects) or propranolol (2.0 mg, eight subjects) into the nonexercising forearm before contraction. Propranolol and vehicle had no effect on forearm vascular responses in the resting arm during SHG in the other arm. In contrast, atropine blocked the vasodilatory response in the resting arm during contraction (delta forearm vascular resistance during contraction, control = -2.1 +/- 0.6 units; postatropine = +0.2 +/- 0.9 units, p less than 0.05). Atropine did not attenuate the vasodilator response to isoproterenol or the vasoconstrictor response to norepinephrine. We conclude 1) a dissociation exists between sympathetic neural and forearm vascular responses to isometric exercise; 2) the vasodilatory response in the nonexercising forearm is not due to sympathetic withdrawal or beta 2-adrenergic-mediated vasodilation; and 3) this response is mediated primarily by cholinergic mechanisms. These studies provide the first direct evidence for active, cholinergically mediated vasodilation during exercise in humans.

Diastolic pressure determines autonomic responses to pressure perturbation in humans

Arterial baroreceptors reflexly regulate sympathetic and heart rate responses to alteration of blood pressure. The primary mechanical determinant of arterial baroreceptor activity in humans remains unclear. We examined the influence of systolic, diastolic, pulse, and mean arterial pressures on efferent muscle sympathetic nerve activity (MSNA, microneurography) and heart rate responses during perturbation of arterial pressure in 10 normal human subjects [age 25 +/- 2 (SE) yr]. We directly measured arterial pressure, heart rate, and MSNA during intravenous vasodilator infusion (nitroprusside, 6 +/- 1 micrograms.kg-1.min-1, n = 6; or hydralazine, 16 +/- 2 mg, n = 4) while central venous pressure was held constant by simultaneous volume expansion. Changes in arterial pressures were compared with changes in heart rate and MSNA over 3-min periods of vasodilator infusion during which we observed increases in systolic and pulse pressures with simultaneous decreases in mean and diastolic pressures. During vasodilator infusion, there were increases in systolic (124.2 +/- 2.1 to 131.7 +/- 2.9 Torr, P less than 0.001) and pulse pressures (57.0 +/- 2.2 to 72.7 +/- 2.7 Torr, P less than 0.001) although mean arterial pressure fell (88.0 +/- 2.6 to 80.4 +/- 2.7 Torr, P less than 0.001) because of decreases in diastolic pressure (67.2 +/- 3.0 to 59.0 +/- 2.7 Torr, P less than 0.001). The changes in arterial pressures were accompanied by simultaneous increases in heart rate (66.4 +/- 3.0 to 92.6 +/- 4.8 beats/min, P less than 0.001) and MSNA (327 +/- 59 to 936 +/- 171 U, P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of aortic baroreflex in regulation of sympathetic responses during hypotension. Evidence from direct sympathetic nerve recordings in humans

Arterial baroreceptors in the carotid sinus and aortic arch regions reflexly regulate heart rate and peripheral vascular responses during changes in arterial pressure. The relative influence of these two arterial baroreflex pathways on the control of these autonomic responses is debatable. Recent studies in our laboratory demonstrate that the aortic baroreflex produces substantial and sustained inhibition of efferent sympathetic nerve activity to muscle (MSNA) during increases in arterial pressure. The regulation of MSNA by these two baroreflexes in humans during hypotension, and particularly the role of the aortic baroreflex, remains undefined. We therefore performed a new series of studies to assess the relative influence of the aortic and carotid baroreflexes on MSNA responses during sustained decreases in arterial pressure. In eight normal male subjects, aged 23 +/- 1 years (mean +/- SEM), we directly measured mean arterial pressure, heart rate, central venous pressure, and MSNA (microneurography) during hypotension (combined aortic and carotid baroreceptor deactivation) produced by intravenous infusion of sodium nitroprusside and during nitroprusside infusion with superimposed application of external neck suction. Neck suction was applied at levels sufficient to maintain transmural carotid sinus pressure above control levels (carotid baroreceptor activation) while the aortic baroreflexes remained deactivated. Central venous pressure was maintained constant with volume infusion. We also studied responses of these same subjects to direct carotid baroreceptor deactivation with the application of external neck pressure. During neck pressure alone, there was a reflex increase in mean arterial pressure; thus, during this portion of the protocol, we achieved carotid baroreceptor deactivation with some aortic baroreceptor activation. Nitroprusside infusion (combined aortic and carotid deactivation) decreased mean arterial pressure from 90.8 +/- 3.1 to 77.8 +/- 1.1 mm Hg (p less than 0.01) with concomitant increases in heart rate from 62.6 +/- 3.0 to 89.7 +/- 6.1 beats/min (p less than 0.001) and in MSNA from 273.8 +/- 43.0 to 950.6 +/- 133.5 units (p less than 0.001). During continued nitroprusside infusion with superimposed neck suction (aortic baroreceptor deactivation and carotid baroreceptor activation), mean arterial pressure decreased to 70.3 +/- 1.9 mm Hg (p less than 0.001 vs. control), heart rate decreased to 82.5 +/- 6.5 beats/min (p less than 0.01 vs. control or vs. nitroprusside alone), but MSNA remained markedly increased at 889.7 +/- 105.1 units (p less than 0.001 vs. control; p = NS vs. nitroprusside alone).(ABSTRACT TRUNCATED AT 400 WORDS)

Cardiopulmonary baroreflexes fail to modulate sympathetic responses during isometric exercise in humans: direct evidence from microneurographic studies

To further evaluate the reported interaction in animals and humans between cardiopulmonary baroreflexes and the somatic pressor reflex, studies were performed in 16 normal men using direct measurements of efferent sympathetic nerve activity to muscle (microneurography) during sustained isometric handgrip (30% maximal voluntary contraction). Forearm vasoconstrictor (plethysmography) and muscle sympathetic nerve activity responses to sustained handgrip were measured during cardiopulmonary baroreceptor deactivation (lower body negative pressure, n = 8) and activation (volume expansion, n = 8). In addition, responses to posthandgrip muscle ischemia were studied during these perturbations of cardiopulmonary baroreflexes. No evidence of an interaction between these two reflex pathways was found. When handgrip was performed during lower body negative pressure, the percent increase in muscle sympathetic nerve activity (+115 +/- 17%) was not different from the sum of the individual sympathetic responses to handgrip and lower body negative pressure performed separately (+106 +/- 19%, p = NS). Likewise, the change in forearm vascular resistance (+3.9 +/- 0.8 U) for sustained handgrip performed during lower body negative pressure was not different from the algebraic sum of the responses to handgrip and lower body negative pressure when these were performed separately (+4.7 +/- 2.7 U, p = NS). No difference was noted in forearm vasoconstrictor and sympathetic nerve activity responses to posthandgrip muscle ischemia and lower body negative pressure when these were performed alone or in combination. Volume expansion also failed to uncover an inhibitory interaction. Handgrip performed before volume expansion resulted in forearm vascular resistance responses (-1.2 +/- 0.9 U) that were not different from the responses when such handgrip was performed after volume infusion (+0.9 +/- 0.9 U, p = NS). Rather than producing the predicted inhibition of muscle sympathetic nerve activity responses to sustained handgrip, volume infusion actually increased these responses. During prevolume sustained handgrip, the increase in sympathetic nerve activity (+64.5 +/- 15.7%) was significantly less than the increase when handgrip was performed after volume infusion (+105.6 +/- 20.1%, p less than 0.01). A similar lack of inhibitory modulation was seen during posthandgrip muscle ischemia performed before and after volume expansion. These data indicate that the efferent sympathetic responses to the somatic pressor reflex are not modulated by the cardiopulmonary baroreflexes in normal humans.

Chyloptysis (chylous sputum) due to thoracic lymphangiectasis with successful surgical correction

A 73-year-old woman with a two-year history of recurrent episodes of respiratory distress is described. The finding of an elevated triglyceride value of 23.4 mmol/L (2072 mg/dL) and a normal cholesterol value in her sputum led to the correct diagnosis of chyloptysis after lymphangiography was performed. It is thought that congenital incompetence of the lymphatic valves was the cause of chyloptysis.

Arterial baroreflex control of sympathetic nerve activity during elevation of blood pressure in normal man: dominance of aortic baroreflexes

Arterial baroreceptors in the carotid sinus (CBR) and aortic arch (ABR) regions exert important control over heart rate and peripheral vascular responses to changes in arterial pressure. The relative roles of these two baroreflex pathways on control of sympathetic nerve activity during sustained elevation of arterial pressure in man is unknown. We therefore studied the relative contributions of the carotid versus the aortic baroreflexes on the control of muscle sympathetic nerve activity (MSNA) during elevation of arterial pressure in normal human subjects. In eight normal men (group I), we measured MSNA (microneurography) during sustained elevation of arterial pressure produced by intravenous infusion of phenylephrine (PE) alone (combined ABR and CBR activation) versus during PE infusion with superimposed application of sustained external neck pressure (NP). NP was applied during sustained PE infusion to eliminate the increase in transmural carotid sinus pressure and thus remove CBR activation, thereby causing ABR stimulation alone. Mean arterial pressure was measured directly, central venous pressure was held constant during PE infusion, and MSNA was measured as total activity (burst frequency X amplitude) and expressed as units. Infusion of PE (ABR and CBR activation) increased mean arterial pressure from 87.2 +/- 2.8 to 94.9 +/- 2.9 mm Hg (+/- SE, p less than .001). This was accompanied by a decrease in heart rate from 65.8 +/- 3.4 to 56.1 +/- 3.3 beats/min (p less than .001) and a decrease in MSNA from 236.2 +/- 47.5 to 84.5 +/- 19.3 units (p less than .001). During infusion of PE with superimposed NP (ABR activation alone), mean arterial pressure increased further to 101.2 +/- 2.9 mm Hg (p less than .001 versus control or PE alone), and heart rate returned to control levels of 62.9 +/- 2.0 beats/min (p = NS vs control; p less than .01 PE vs PE plus NP), but MSNA remained reduced at 48.6 +/- 9.2 units (p less than .01 vs control; p = NS vs PE alone). Thus, combined activation of ABR and CBR resulted in a 65 +/- 5% attenution of MSNA, while activation of ABR alone resulted in a 73 +/- 7% attenuation of MSNA. In a separate series of experiments in seven subjects (group II) we used sustained external neck suction alone to activate the CBR (leaving the ABR either unchanged or minimally deactivated) and studied the MSNA responses to this CBR activation.(ABSTRACT TRUNCATED AT 400 WORDS)

Increased hypoxic ventilatory drive due to administration of aminophylline in normal men

We evaluated the effects of intravenous administration and five days of oral administration of aminophylline on hypoxic and hypercapnic ventilatory drives in seven normal men. Serum levels of theophylline were 13.2 micrograms/ml +/- 1.0 micrograms/ml (mean +/- SD) after intravenous administration of aminophylline and 8.8 micrograms/ml +/- 1.7 micrograms/ml after oral administration of aminophylline. Aminophylline had no effect on the slope of the line for carbon dioxide response or on hypoxic ventilatory drive, measured at resting alveolar carbon dioxide tension (PACO2). Hypoxic ventilatory drive was significantly increased (P < 0.025) after intravenous administration of aminophylline when the PACO2 was raised to the control level before aminophylline. Intravenously administered aminophylline shifted the intercept of the line for carbon dioxide response from 40.7 +/- 2.3 to 32.9 +/- 4.6 mm Hg (P < 0.005) and lowered the resting PACO2 from 38.3 +/- 1.8 to 33.7 +/- 2.1 mm Hg (P < 0.005). Similar but smaller changes were seen after oral administration of aminophylline. There was a significant correlation between end-tidal carbon dioxide tension and the serum level of theophylline (P < 0.001), indicating that aminophylline stimulates ventilation in a dose-dependent fashion. This increase in ventilation is due in part to an increase in hypoxic ventilatory drive.

Prolonged survival in an adult with cystic fibrosis

Cystic fibrosis in patients over 40 is rare. We report a 52-year-old woman in whom cystic fibrosis was confirmed by sweat analysis. This patient represents the oldest cystic fibrosis patient (with confirmatory sweat chlorides) ever described. We conclude that any patient with the appropriate clinical presentation, regardless of age, should be investigated for cystic fibrosis.

Exfoliative cytology in the rapid diagnosis of pulmonary blastomycosis

Four patients with pulmonary blastomycosis are reported. Their bronchial washings, submitted for cytologic evaluation and stained by the standard Papanicolau technique, yielded the diagnosis, subsequently confirmed by cultural identification of the fungus. In three additional cases, retrospective evaluation of cytologic material also revealed the organism, even though the diagnostic significance was not appreciated originally. Since cytologic techniques are simple, readily available, and rapid, they can be helpful in differentiating pulmonary neoplasms from pulmonary blastomycosis, thus reducing the need for diagnostic thoracotomies.