Extent and Localization of Changes in Upper Airway Caliber with Varying Concentrations of Sevoflurane in Children

Background: Previous studies in humans suggest that inhibition of upper airway muscle activity is independent of the dose of inhalational anesthesia. Whether a dose-independent relation applies to changes in airway caliber is unknown. The authors sought to evaluate the configurational changes that lead to upper airway narrowing during inhalational anesthesia with sevoflurane and to determine whether these changes are dose dependent within a clinically relevant dose range.

Methods: Fifteen children undergoing elective magnetic resonance imaging of the brain were studied. Magnetic resonance images of the upper airway were acquired at sevoflurane concentrations of 0.5, 1.0, and 1.5 minimum alveolar concentration (MAC), administered in random sequence. At least 15 min was allowed for equilibration of inspired and alveolar partial pressures of sevoflurane. Images were acquired in early expiration at the level of the soft palate, base of the tongue, and tip of the epiglottis. Airway cross-sectional area (CSA), anteroposterior, and transverse dimension were determined using image-analysis software.

Results: At each anatomical level, pharyngeal CSA decreased progressively with increasing depth of sevoflurane anesthesia (P < 0.001). Increasing the sevoflurane concentration from 0.5 to 1.0 MAC reduced airway CSA by 13-18%, and a further increase to 1.5 MAC resulted in an overall 28-34% reduction in CSA. The reduction in CSA was predominantly due to a decrease in anteroposterior dimension.     

Do characteristics of informal caregivers affect the length of hospital stay for frail elders?

Studies examining the length of hospital stay for the very old rarely include characteristics of the informal caregiver as potentially explanatory variables. This study expanded a frequently used conceptual model of health services use to include caregiving factors as enabling variables. Data were collected from a representative sample of frail elders who had been hospitalized in the previous 18 months (n = 181) and their primary informal caregivers. The findings indicate that elders whose primary caregiver was a coresiding offspring had shorter hospitalization than elders whose offspring caregiver lived in different households. These data indicate that the amount of variance explained by this conceptual model is increased when social factors are included as explanatory variables.     

Prolonged Q-T interval syndrome. Successful treatment with combined ventricular pacing and propanolol.

A case of the sporadic variety of the prolonged Q-T interval syndrome without deafness is presented. The patient is unusual because of a long survival to age 13, despite progressive worsening of her disease, and the presence of marked atrioventricular conduction abnormalities in addition to the usual ventricular trachyarrhythmias. Successful therapy was finally achieved with a combination of permanent pervenous ventricular pacing and propranolol.     

Lu9, another new antigen of the Lutheran blood-group system

Abstract. A new Lutheran antigen, Lu9, with a frequency of about 2%, has been recognized. It has an apparent allelic relationship to the high-frequency character Lu6.     

Aortic valve sclerosis, mitral annular calcium, and aortic root sclerosis as markers of atherosclerosis in men

Aortic valve sclerosis (AVS) and mitral annular calcium (MAC) as detected by transthoracic echocardiography have been associated with atherosclerosis. Aortic root sclerosis (ARS) may have a similar association, but has not been studied. This study evaluates, by transesophageal echocardiography, the association of AVS, MAC, and ARS with aortic atheromatous disease and cardiovascular disease. Multiplane transesophageal echocardiography with evaluation of AVS, MAC, ARS, and aortic atheromatous disease by 2 experienced observers unaware of clinical data was performed in 157 male patients > or =50 years old. The presence of cardiovascular disease, defined as coronary, carotid, or peripheral artery disease, was determined by specific criteria. The prevalence of AVS, MAC, ARS, and aortic atheromatous disease was 42%, 30%, 48%, and 71%, respectively. The presence of AVS, MAC, or ARS was highly associated with aortic atheromatous disease (odds ratio 4.9 to 12.0, confidence interval 1.4 to 35.8, p <0.001). ARS was also associated with cardiovascular disease (odds ratio 2.2, confidence interval 1.0 to 4.5, p = 0.038). The presence of AVS, MAC, or ARS had a sensitivity of 77%, specificity of 72%, a positive predictive value of 88%, and a negative predictive value of 55% for aortic atheromatous disease. We concluded that the prevalence of AVS, MAC, or ARS by transesophageal echocardiography in men is common, and their presence is highly associated with aortic atheromatous disease and coronary, carotid, or peripheral artery disease.     

Transmission of Non-A, Non-B Hepatitis by pH4-Treated Intravenous Immunoglobulin

Four patients (2 with X-linked, one with common variable hypogammaglobulinaemia, and 1 with ulcerative colitis) developed non-A, non-B hepatitis (NANBH) following administration of a specific batch of intravenous immunoglobulin (IV IgG) manufactured by the Scottish National Blood Transfusion Service using the pH4/mild pepsin method. Each patient had normal serum ALT levels over a preceding period of 12-67 months, with raised values developing within 4-18 weeks of first administration of the implicated batch. Two patients had very mild symptoms of hepatitis, the other 2 being asymptomatic. Over a follow-up period of 8-12 months, ALT levels returned to normal in 3 patients, but biopsy-proven chronic NANBH developed in the fourth. The level of NANBH virus in the starting plasma used to manufacture this batch may have exceeded the capacity of the process to inactivate the virus. The transmission of NANBH by one of approximately 110 batches administered demonstrates the importance of continued close surveillance of recipients of IV IgG, even if asymptomatic, by regular monitoring of liver function tests and recording of all batches received.     

CD4 memory T cells divide poorly in response to antigen because of their cytokine profile

Immunological memory is a hallmark of adaptive immunity, and understanding T cell memory will be central to the development of effective cell-mediated vaccines. The characteristics and functions of CD4 memory cells have not been well defined. Here we demonstrate that the increased size of the secondary response is solely a consequence of the increased antigen-specific precursor frequency within the memory pool. Memory cells proliferated less than primary responding cells, even within the same host. By analyzing the entry of primary and memory cells into the cell cycle, we found that the two populations proliferated similarly until day 5; after this time, fewer of the reactivated memory cells proliferated. At this time, fewer of the reactivated memory cells made IL-2 than primary responding cells, but more made IFNγ. Both these factors affected the low proliferation of the memory cells, because either exogenous IL-2 or inhibition of IFNγ increased the proliferation of the memory cells.