Comparison of measles virus-specific antibodies with antibody-dependent cellular cytotoxicity and neutralizing functions

Measles virus-specific antibodies with antibody-dependent cellular cytotoxicity (ADCC) and neutralizing functions were compared in 25 healthy women. ADCC antibody was measured in a 12-h 51Cr release assay using peripheral blood mononuclear cells as effectors and Raji cells persistently infected with measles as targets. Neutralizing antibody was determined by the plaque neutralization test (PNT). ADCC and PNT titers correlated well (r = .80, P < .001). ADCC titers ranged from < 10 to > 10(6) and averaged 1.3 logs higher than PNT titers. Three sera with PNT titers of < 120, including 1 with a titer of < 8 (< 10(0.9)), had ADCC titers of > or = 10(2.5). Among subjects born in the United States, ADCC titers, but not PNT titers, correlated inversely with the year of birth, suggesting that ADCC antibody may be more indicative than neutralizing antibody of differences between naturally and vaccine-acquired immunity. These data suggest a possible role for ADCC in protection or recovery from measles.

Anterior lingual mandibular salivary gland defect--a dilemma in diagnosis

Anterior lingual mandibular salivary gland defects are very rare. These lesions present as non-definitive bony radiolucencies. There are several other radiolucent entities which present in the anterior mandible with greater frequency and this creates a diagnostic dilemma for the practitioner. The ultimate and proper treatment of non-treatment depends on a correct diagnosis of these lesions. The correctness of the diagnosis and avoidance of unnecessary traumatic procedures may be aided by more sophisticated radiographic studies, such as a CAT scan and/or Magnetic Resonance Imaging. A case of a very unusual appearing anterior lingual mandibular salivary gland defect is presented and the diagnosis, management and recommendation for more complex radiographic studies are discussed.

A new geometric description of the right ventricle

An accurate model of the geometry of the right ventricle would be particularly useful for volume determination by imaging techniques, as well as for mechanical modelling. In this study, a new mathematical model for the right ventricle geometry based on its crescentic cross-sectional shape is proposed and used to calculate its volume in imaged ex-vivo casts. An excellent correlation (r = 0.97) was found between volume as derived from the model and actual volume measured by water displacement.

"Ethics and clinical research" revisited. A tribute to Henry K. Beecher

The doctrine of informed consent, borrowed from the law of torts, cannot be readily transplanted into therapeutic settings. The broader, as yet unrealized, idea of informed consent, which suggests that parties must make decisions jointly, should guide interactions between physicians and patients or investigators and subjects.

Clustering of xerophthalmia within households and villages

The clustering of xerophthalmia within households and villages was estimated among preschool age children using data from studies conducted in Malawi, Zambia, Indonesia and Nepal over the past decade. Pairwise odds ratios (OR) were used to measure the magnitude of clustering. This OR measures the risk of xerophthalmia for a preschool child given that another randomly chosen preschool child from the same household (or same village but different household) had xerophthalmia, relative to the risk if that randomly chosen preschool child did not have xerophthalmia. Village pairwise OR ranged from 1.2 in Malawi to 2.2 in Nepal. Household pairwise OR ranged from 4.4 in Malawi to 9.7 in Indonesia, indicating that xerophthalmia clustering was much greater within households than villages. The magnitude of this clustering was as large, or larger than, infectious outcomes such as diarrhoea, fever and cough. Although xerophthalmia was associated with a weekly history of infectious morbidity, the clustering of diarrhoea, fever and cough explained very little of the xerophthalmia clustering observed in each of these studies, Hence, other household factors such as food availability and dietary practices should be examined for their role in the clustering of xerophthalmia within certain households.

System analysis of CCD-based bar code readers

The basic constraints on the working range of CCD-based bar code readers are analyzed. A comprehensive model that allows the calculation of the optimal working range and its corresponding optical system parameters is derived. Experimental results are found to be in good agreement with theoretical calculations. Finally, comparisons between bar code laser scanners and CCD readers are presented.

Protective salivary immunoglobulin A responses against Streptococcus mutans infection after intranasal immunization with S. mutans antigen I/II coupled to the B subunit of cholera toxin

The B subunit of cholera toxin (CTB) has been shown to augment mucosal responses to microbial virulence antigens, including those of Streptococcus mutans, which is the principal etiologic agent of dental caries. In the present study, the surface fibrillar protein antigen of S. mutans, antigen I/II (Ag I/II), was chemically coupled to CTB (Ag I/II-CTB), and the conjugate was examined for its effectiveness in inducing salivary immune responses protective against S. mutans infection. Weanling Fischer rats were given Ag I/II-CTB (50 micrograms) by the intranasal route and then orally infected with a virulent strain of S. mutans. Gnotobiotic or conventional rats were given two or three additional immunizations, respectively, at about 2-week intervals. One week after each immunization, individual serum, saliva, and fecal samples were collected and stored frozen until assayed for antibody activity to Ag I/II and cholera toxin (CT) by an enzyme-linked immunosorbent assay. The rats were sacrificed 1 week after the last immunization, when mandibles were also collected from individual rats for assessment of S. mutans levels in plaque and caries activity. Rats immunized only or both immunized and infected showed a salivary immunoglobulin A (IgA) anti-Ag I/II response which reached significantly (P < 0.05) higher levels than those seen in nonimmunized, infected controls. A salivary IgA anti-Ag I/II response was also seen in rats infected only with S. mutans. Essentially no salivary antibody activity to CT was detected. Some serum anti-Ag I/II and anti-CT responses were seen in immunized animals. Serum IgG anti-Ag I/II responses were seen in immunized, infected rats and also in infected-only rats, suggesting that the responses were a result of infection with S. mutans. The immunized and infected rats had significantly (P < 0.05) lower levels of S. mutans in plaque and lower caries activity than nonimmunized, infected rats. These results indicated that intranasal immunization of rats with Ag I/II-CTB induced a protective salivary immune response which was associated with a reduction in S. mutans colonization and S. mutans-induced dental caries.

Estimation of right ventricular mass in normal subjects and in patients with primary pulmonary hypertension by nuclear magnetic resonance imaging

OBJECTIVES

This study was designed to test the accuracy of nuclear magnetic resonance (NMR) imaging as a noninvasive technique for estimating right ventricular mass in normal subjects and in patients with primary pulmonary hypertension.

BACKGROUND

An accurate means of noninvasively estimating right ventricular mass may allow better characterization of the degree of right-sided pressure or volume overload caused by underlying cardiac or pulmonary diseases.

METHODS

End-diastolic short-axis electrocardiogram (ECG)-gated spin echo NMR images of the heart were obtained in vivo in 13 patients with primary pulmonary hypertension and 10 normal adult volunteers. Both right and left ventricular mass were computed by summing the myocardial slice volumes over all slices spanning the myocardium and multiplying by myocardial density. This technique of myocardial mass determination was verified by imaging 10 calf hearts and comparing the NMR-determined right and left myocardial mass with the actual mass determined by weighing the right and left ventricles.

RESULTS

In the calf heart study, an excellent correlation was obtained between the directly measured ventricular mass and the NMR-calculated mass, for both the right and the left ventricle. Patients with primary pulmonary hypertension had an elevated right ventricular mass index compared with that of normal subjects (62.69 +/- 8.72 g/m2 vs. 23.32 +/- 1.36 g/m2, p < 0.0005). There was no significant difference in left ventricular mass index between the two groups. Both mean intraobserver and inter-observer variability in myocardial mass determination were low. Linear regression analysis between right ventricular mass index and mean pulmonary artery pressure was significant (r = 0.75, p < 0.003).

CONCLUSIONS

Electrocardiogram-gated spin echo NMR imaging of the heart may be used for quantitating right ventricular mass in normal subjects and in patients with primary pulmonary hypertension, in whom it may also provide an alternative noninvasive technique for estimating mean pulmonary artery pressure.

Comparison of nucleic acid hybridization and nucleic acid amplification using conserved sequences from the 5' noncoding region for detection of bovine viral diarrhea virus

Primers and probes derived from conserved sequences located in the 5' noncoding region of pestiviruses were evaluated for detection of bovine viral diarrhea virus. With these reagents, hybridization and polymerase chain reaction tests detected 62 of 90 and 90 of 90 bovine viral diarrhea virus isolates, respectively. A quick lysis method for preparing RNA for use in polymerase chain reaction amplification also was evaluated.

Use of the carbon dioxide laser to locate small sialoliths

Six cases of small salivary duct sialoliths were treated using the carbon dioxide laser as a surgical dissector. When the laser beam encountered the small sialolith (3 mm or less), a light-scattering effect (flash or burst) was observed, thus enabling an almost immediate localization of the stone in the salivary duct or in the surrounding tissue. Stone extirpation is more rapid, with less surgical trauma, using this technique.

A mathematical model of the right ventricular muscle geometry and mass

An understanding of the geometry of the right ventricular (RV) free wall is imperative for both modelling its mechanics and assessing its mass by imaging techniques such as echocardiography. In this paper, a new model of the RV free wall geometry is discussed in which the wall is assumed to have a parabolic long-axis and a circular short-axis curvature respectively. By use of analytic geometry, mathematical expressions for RV surface area, volume and mass were derived. In vitro model validation was carried out in the following manner: (1) echocardiographic images of 16 isolated calf hearts were obtained; (2) measurements were made from the images to determine the parameters required by the model; (3) wall mass was determined by use of these parameters; and (4) the calculated wall mass was then compared with actual RV wall mass (determined by weighting). The model was found to be very accurate for determination of RV free wall mass (R = 0.92); it should prove useful in the study of the stress-strain relationships for the RV and for precise quantitative assessment of RV free wall mass.

Estimation of myocardial water content using transverse relaxation time from dual spin-echo magnetic resonance imaging

Dual spin-echo magnetic resonance imaging may be used for calculation of transverse myocardial relaxation time from the signal intensity of the echoes considered. In this study, the ability of myocardial transverse relaxation time (T2) to quantitate myocardial edema of the right ventricle (RV) and left ventricle (LV) was tested. Dual spin-echo magnetic resonance images of the entire hearts were obtained and T2 of the RV and LV myocardium calculated from the signal intensities within multiple regions of interest distributed over the myocardium. Six hearts were intermittently perfused through an aortic cannula with three perfusates of decreasing osmolality. Biopsies were obtained for water content (WC) analysis both before and after imaging the hearts at baseline and post-perfusion. A seventh (control) heart was not perfused; instead dual spin-echo imaging was performed at the same time intervals as in the perfused hearts. Prior to any intervention, there was no significant difference between baseline RV (79.49 +/- 2.10%) and LV (77.99 +/- 2.44%, p = .2) myocardial water content; RV myocardial T2 (59.9 +/- 5.8 msec) was slightly but not significantly longer than that of the LV (54.6 +/- 5.7 msec, p = .1). After induction of edema, strong correlation was found between right ventricular myocardial water content measurements and right ventricular T2 (RV WC = 68.5 + 0.19 x RV T2; N = 27, R = 0.92, p < .0001, SEE = 1.56%). Similarly, strong correlation was found between left ventricular myocardial water content and T2 (LV WC = 62.1 + 0.29 x LV T2; N = 27, R = 0.92, p < .0001, SEE = 1.80%).(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging for quantitation of right ventricular volume in patients with pulmonary hypertension

Evaluation of right ventricular function in patients with right-sided heart failure is difficult because of the complex anatomy of the right ventricle; the distinct geometry of the dilating, failing right ventricle; its variance from the typical oblate spheroid shape used to model the left ventricle; associated cardiac lesions in patients with right ventricular failure (including tricuspid and pulmonary regurgitation); and the inherent risk of conventional contrast ventriculography. With magnetic resonance techniques, tomographic images of the heart may be obtained at multiple points in the cardiac cycle without the use of intravascular contrast agents. From the end-diastolic and end-systolic images, chamber volume may then be determined directly without any modeling assumptions as to the geometry of the ventricular chamber.