Thunderstorm asthma in seasonal allergic rhinitis: The TAISAR study

BACKGROUND

Asthma epidemics associated with thunderstorms have had catastrophic effects on individuals and emergency services. Seasonal allergic rhinitis (SAR) is present in the vast majority of people who develop thunderstorm asthma (TA), but there is little evidence regarding risk factors for TA among the SAR population.

OBJECTIVE

We sought to identify risk factors for a history of TA and hospital presentation in a cohort of individuals with SAR.

METHODS

This multicenter study recruited adults from Melbourne, Australia, with a past diagnosis of TA and/or self-reported SAR. Clinical information, spirometry results, white blood cell count, ryegrass pollen-specific (RGP-sp) IgE concentration, and fractional exhaled nitric oxide were measured to identify risk factors for a history of TA in individuals with SAR.

RESULTS

From a total of 228 individuals with SAR, 35% (80 of 228) reported SAR only (the I-SAR group), 37% (84 of 228) reported TA symptoms but had not attended hospital for treatment (the O-TA group), and 28% (64 of 228) had presented to the hospital for TA (the H-TA group). All patients in the H-TA group reported a previous asthma diagnosis. Logistic regression analysis of factors associated with O-TA and H-TA indicated that lower FEV1 value and an Asthma Control Questionnaire score higher than 1.5 were associated with H-TA. Higher blood RGP-sp IgE concentration, eosinophil counts, and fractional exhaled nitric oxide level were significantly associated with both O-TA and H-TA. Receiver operating curve analysis showed an RGP-sp IgE concentration higher than 10.1 kU/L and a prebronchodilator FEV1 value of 90% or lower to be biomarkers of increased H-TA risk.

CONCLUSION

Clinical tests can identify risk of a history of TA in individuals with SAR and thereby inform patient-specific treatment recommendations.

Estimation of the physical properties of nanocomposites by finite-element discretization and Monte Carlo simulation

This paper reviews and enhances numerical models for determining thermal, elastic and electrical properties of carbon nanotube-reinforced polymer composites. For the determination of the effective stress-strain curve and thermal conductivity of the composite material, finite-element analysis (FEA), in conjunction with the embedded fibre method (EFM), is used. Variable nanotube geometry, alignment and waviness are taken into account. First, a random morphology of a user-defined volume fraction of nanotubes is generated, and their properties are incorporated into the polymer matrix using the EFM. Next, incremental and iterative FEA approaches are used for the determination of the nonlinear properties of the nanocomposite. For the determination of the electrical properties, a spanning network identification algorithm is used. First, a realistic nanotube morphology is generated from input parameters defined by the user. The spanning network algorithm then determines the connectivity between nanotubes in a representative volume element. Then, interconnected nanotube networks are converted to equivalent resistor circuits. Finally, Kirchhoff's current law is used in conjunction with FEA to solve for the voltages and currents in the system and thus calculate the effective electrical conductivity of the nanocomposite. The model accounts for electrical transport mechanisms such as electron hopping and simultaneously calculates percolation probability, identifies the backbone and determines the effective conductivity. Monte Carlo analysis of 500 random microstructures is performed to capture the stochastic nature of the fibre generation and to derive statistically reliable results. The models are validated by comparison with various experimental datasets reported in the recent literature.

Constrictive pericarditis after coronary artery bypass surgery as a cause of unexplained dyspnea: a report of five cases

Constrictive pericarditis after coronary artery bypass grafting (CABG) is rare and can present as unexplained dyspnea. We report five consecutive cases of post-CABG constrictive pericarditis seen within a period of 17 months at our institution. All patients presented with heart failure of unknown etiology within a period of 8-84 months after surgery. During the initial post-CABG period, two patients had developed postcardiotomy syndrome that was successfully treated with steroids. They were all assessed noninvasively and invasively. In all patients, the diagnosis of constriction was initially suspected clinically (symptoms, high jugular venous pressure with deep "X" and "Y" descents, pericardial knock). Echocardiography showed transmitral flow typical of constriction in all patients and hepatic venous flow in two. Two patients showed rapid left ventricular relaxation. In all patients, hemodynamic assessment showed diastolic equalization of pressures in all chambers, "W" shape waveform in right atrial pressure, and "dip and plateau" configuration in right and left ventricular pressure waveforms. Diagnosis was confirmed surgically in four patients who were subjected to pericardiectomy-pericardial stripping (three survived, one died). One patient refused surgery. We conclude that constrictive pericarditis, although rare, should be suspected in every case of unexplained dyspnea post CABG. It can appear early or late after surgery, and clinical examination plays an important role in its early recognition. It requires a full noninvasive and invasive assessment in case of clinical suspicion.

The effect of milrinone on metabolism after cardiopulmonary bypass

AIM

The aim of this study was to examine the effects of milrinone on tissue metabolism perioperatively in cardiac surgery patients using extracorporeal circulation, in comparison to adrenaline and placebo. These effects were measured indirectly by measuring serum lactate, base excess and glucose levels at standard intervals.

METHODS

Seventy-seven consecutive patients, who underwent elective cardiac surgery, were allocated in 3 groups. Inotropic support was initiated coming off CPB (cardiopulmonary bypass) if there was evidence of hypotension (mean arterial pressure [MAP] <60 mmHg), after adequate preload (pulmonary capillary wedge pressure [PCWP] >10 mmHg). Milrinone was used in patients with pulmonary hypertension (MPAP >20 mmHg). Group 1 (N.=26) received no inotropes, placebo. Group 2 (N.=32) received adrenaline. Group 3 (N.=19) received adrenaline + milrinone at 0.5 microg/kg/min infusion. Adrenaline was infused at a variable dose (0.01-0.02 microg/kg/min) to achieve a MAP >60 mmHg. The serum lactate, base excess and glucose levels were measured at standard intervals in all 3 groups. Diabetic, hepatic or renal failure patients (serum creatinine >2 mg/dL), were excluded from the study. Patient demographic and clinical characteristics were similar in all 3 groups.

RESULTS

Repeated measure analysis of variance between groups showed significantly lower serum lactate levels and higher base excess in the milrinone group (P<0.05), after 2 to 4 hours of treatment. Serum glucose levels were higher in the adrenaline group (P=0.01). There were no immediate complications, morbidity or mortality in the study groups.

CONCLUSION

These findings suggest that milrinone has a beneficiary effect on aerobic tissue metabolism after extracorporeal circulation, reflected on serum lactate, base excess and glucose levels, possibly due to a combination of positive inotropic and peripheral vasodilatory effect of the drug.

The supportive value of pre-bypass L-glutamate loading in patients undergoing coronary artery bypass grafting

AIM

Experimental studies have demonstrated that an exogenous supply of glutamate improves mechanical function and recovery of ischemic myocardium. The aim of the present study was to investigate the effect of myocardial pre-bypass loading with glutamate on myocardial protection during global ischemia and reperfusion of patients undergoing coronary artery bypass grafting (CABG).

METHODS

The study was double blinded. Twenty patients undergoing elective CABG were randomized to receive L-glutamate (n = 10) or normal saline (n = 10). Intracellular levels of glutamate, ATP and lactate were measured in left ventricular biopsies collected 10 min after aortic clamp release. Hemodynamic data, and postoperative release of CK-MB and troponin T were also measured.

RESULTS

Pre-bypass administration of glutamate resulted in myocardial glutamate loading since glutamate levels were significantly higher in the glutamate group of patients than in controls (18.6 +/- 3.1 versus 8.7 +/- 1.2 microg/g tissue, P < 0.001). In the same group ATP levels were also significantly higher (2.4 +/- 0.7 versus 1.5 +/- 0.4 microg/g tissue, P < 0.05) and lactate levels significantly less than in controls (6.9 +/- 1.9 versus 12.0 +/- 2.1 microg/g tissue, P < 0.001). Glutamate patients had statistically significantly superior post-bypass hemodynamic performance (cardiac index, left ventricular stroke work index, systemic vascular resistance and pulmonary vascular resistance). Statistically significantly lower levels of CK-MB (6 h postoperative), total and peak CK-MB, troponin T (24 h postoperative), and total troponin T were found in the glutamate group.

CONCLUSIONS

The results of this preliminary study indicate that pre-bypass intravenous administration of glutamate in patients undergoing CABG has a supportive effect on myocardial metabolism during global ischemia and reperfusion, improves patients' postoperative hemodynamic performance and reduces postoperative cardiac enzyme release.

A comprehensive approach to enhancing sexual health education in the Case Western Reserve University School of Medicine

We report on the Sexual Health Curriculum Enhancement project at Case Western Reserve University School of Medicine. Using a US dollars 100000 grant from Pfizer Pharmaceuticals, Inc., we have developed and are in the process of implementing a comprehensive, cross-disciplinary and innovative curriculum that is based on three primary objectives for teaching sexual health: attitude change, behavior change, and knowledge acquisition. Five general strategies to incorporate specific sexual health content into the medical school curriculum have been implemented: (1). Faculty Development; (2). Additional Didactics; (3). Cased-Based Learning; (4). Testing and Assessment; and (5). Electronic (Computer/Web-Based Enhancements).

Prophylactic treatment with cimetidine after renal transplantation

17 consecutive patients who underwent renal transplantation during the period 1979-1981 and were at risk of gastrointestinal hemorrhage were treated prophylactically with the histamine H2-blocker cimetidine without antacids. The incidence of gastrointestinal bleeding, the number of rejection episodes and graft survival were compared with 17 patients, who had received renal transplant during the period 1976-1978 and had not received cimetidine. The incidence of gastrointestinal hemorrhage was not reduced in the cimetidine-treated patients. In addition, cimetidine treatment neither increased the total number of rejection episodes nor changed the long-term graft survival. The results of this study indicate that cimetidine does not appear to be superior to antacids in the prevention of gastrointestinal bleeding in renal transplant recipients.

The effects of canrenoate K on corticosteroid biosynthesis in nephrectomized dogs

There is evidence from in vitro experiments that spironolactone not only antagonises the peripheral effects of aldosterone but also inhibits the production of corticosteroids by the adrenals. However relevant data from clinical studies are contradictory probably because spironolactone action on the kidneys also activates other mechanisms, such as renin secretion and potassium retention, which are potent stimulants of the adrenal cortex and thus tend to compensate for the inhibition. To determine the inhibitory effect of spironolactone on the adrenals in isolation, three groups of nephrectomized dogs were studied. Steroidogenesis was stimulated either by angiotensin II, potassium, or ACTH infusion. Potassium canrenoate was administered i.v. bolus at the beginning of the experiment. All the groups showed a similar marked decrease in plasma renin activity (PRA). Plasma aldosterone and cortisol were stimulated by the appropriate stimulus but their increase was blunted after the canrenoate K administration. The altered response between the subgroups was statistically significant (P less than 0.05). Plasma progesterone increased after the administration of canrenoate K. The response difference between the respective subgroups was again statistically significant (P less than 0.05). Canrenoate K was rapidly eliminated from the systemic circulation. These data indicate that canrenoate K causes a partial inhibition of aldosterone and cortisol stimulated secretion but augments the plasma levels of the precursor progesterone, as would be expected following inhibition of specific steps of corticosteroid biosynthesis.

Inferior vena cava thrombosis due to migration of retained functionless pacemaker electrode

Thrombosis of the inferior vena cava due to migration of a pacing wire has not been published previously. We describe such a complication due to migration of a retained pacemaker electrode. The distal cut end of the wire was found looped at the level of thrombosis of the inferior vena cava. The patient was treated initially with heparin and placed later on coumadin. Currently, he is doing well without any evidence of thromboembolism.

[Surgery of pulmonary hydatid diseases in childhood]

Fourteen cases of hydatid cysts of the lung in childhood are reported. The lung organ constitutes the most frequent site of the disease in childhood. The possible pathogenetic factors and the complications such as rupture and suppuration of the cyst are described. Conservative surgical procedures are recommended. The value of prophylaxis against the disease in infants and young children is emphasised.