From genome to proteome: protein map of Haemophilus influenzae

High-resolution two-dimensional (2-D) polyacrylamide gel electrophoresis allows the separation of complex biological mixtures (i.e., several hundred proteins from a bacterial cell lysate) in a single experiment. In this report proteins from Haemophilus influenzae were separated by 2-D gels and analyzed by peptide mass fingerprinting and/or amino acid analysis. By comparing the peptide mass profiles and the amino acid composition with the Haemophilus influenzae database, 119 protein spots were identified. The combination of amino acid analysis and peptide mass fingerprinting is a powerful tool for a rapid and economical identification of a large number of proteins resolved by 2-D gels. Studies on gene regulation and changes of protein expression upon drug treatment require quick and serial analysis techniques to efficiently identify potential new drug targets.     

In vitro toothbrush-dentifrice abrasion of resin-modified glass ionomers

OBJECTIVES: The three purposes of this study are to: (1) describe the relationship between the prevalence of coronal caries and root caries; (2) describe the relationship between the three-year incidence of coronal caries and root caries; and (3) if the two conditions are associated, develop a multiple regression model that identifies characteristics distinguishing people who had increments of both root caries and coronal caries from people who had increments of either coronal caries or root caries, or who had no new caries. METHODS: Dental examinations and interviews were conducted in the homes of a randomly selected, stratified sample of people over the age of 65 years in five North Carolina counties. The relationships between coronal and root D and DF were analyzed through contingency table analyses, and ordinal logistic regression was used to identify characteristics that differentiated people who had both coronal and root D over the three years from people who had either coronal or root D and people who had no new disease. RESULTS: Evidence of root and coronal caries in whites was much more likely to be in the form of fillings, while for blacks, it was more likely to be in the form of untreated decay. Prevalence rates of coronal and root D and DF were significantly associated for both blacks and whites. Incidence rates based on DF indicated that root and coronal caries were not associated in whites, but were associated in blacks. People more likely to experience both types of caries had more gingival recession at baseline, greater average attachment loss over the three years, and lactobacilli at baseline. In addition, the presence of Porphymonas gingivalis at three years was important for whites. CONCLUSIONS: It appears that coronal and root caries do tend to appear together in the same individuals, but fillings attenuate that relationship. The impact of dental treatment on the epidemiology of dental caries appears to be considerable and calls into question whether the F component of the caries index is related to disease as defined by epidemiologic criteria.     

Dental evidence for the peopling of the New World: some methodological considerations

Turner (1985b) and Greenberg et al. (1986) proposed that New World populations originated in northern Asia and entered the Americas in three migratory waves: Macro-Indian, Aleut-Eskimo, and Na-Dene. Biological support for this model comes from Turner's unweighted pair group (UPGMA) cluster analysis of discrete dental traits in world populations. Unfortunately, UPGMA analysis often creates suspect clusters and may not be valid as a method for displaying evolutionary relationships because it assumes that rates of evolution are equal among all populations. To test whether Turner's results are an artifact of his analytical method, I analyzed his published data (Turner 1985b) using two alternative techniques that do not assume homogeneous rates of change: a Wagner distance algorithm employing the Fitch-Margoliash criterion for goodness of fit and a maximum parsimony analysis using segment-coded dental trait frequencies. Both alternative methods produce trees that are similar to the UPGMA analysis results, supporting Turner's original results and basic conclusions. Comparisons of tree topology demonstrate that there is strong congruence between trees produced by all three methods, although the placement of certain populations, such as Na-Dene, depends on the method of analysis employed.     

Effect of furosemide and intravenous normal saline fluid load upon the renal resistive index in nonobstructed kidneys in children

Recent literature has shown that relative to baseline the renal resistive index remains unchanged in nonobstructed kidneys and increases in obstructed kidneys after administration of furosemide. To our knowledge the effect upon the renal resistive index of furosemide administered in conjunction with intravenous normal saline fluid load has not been reported. We evaluated the renal resistive index in 13 nonobstructed kidneys in 8 children 6 to 18 years old before and after furosemide and intravenous normal saline fluid load. The mean resistive index decreased from baseline (mean decrease was 0.06 +/- 0.06 standard deviation), with the observation of a resistive index decrease significant to p < 0.005). It appears likely that the combination of an intravenous normal saline fluid load and furosemide caused the resistive index decrease, since a decrease was not observed with furosemide alone; however, these results cannot exclude the possibility that the resistive index decrease was due to the intravenous normal saline fluid load alone. Nonetheless, these data are important since they may provide the foundation for the development of a pharmacologically challenged Doppler sonographic examination using furosemide and intravenous normal saline fluid load to evaluate better potentially obstructed kidneys.     

Assessment of baroreceptor-cardiac reflex sensitivity using time domain analysis in patients with IDDM and the relation to left ventricular mass index

Autonomic dysfunction in insulin-dependent diabetic (IDDM) patients has been associated with abnormalities of left ventricular function and an increased risk of sudden death. A group of 30 patients with IDDM and 30 age, sex and blood pressure matched control subjects underwent traditional tests of autonomic function. In addition, baroreceptor-cardiac reflex sensitivity (BRS) was assessed using time domain (sequence) analysis of systolic blood pressure and pulse interval data recorded non-invasively using the Finapres beat-to-beat blood pressure recording system. 'Up BRS' sequences-increases in systolic blood pressure associated with lengthening of R-R interval, and 'down BRS' sequences-decreases in systolic blood pressure associated with shortening of R-R interval were identified and BRS calculated from the regression of systolic blood pressure on R-R interval for all sequences. We also assessed heart rate variability using power spectral analysis and, after expressing components of the spectrum in normalised units, assessed sympathovagal balance from the ratio of low to high frequency powers. IDDM subjects underwent 2-D echocardiography to assess left ventricular mass index. Standard tests of autonomic function revealed no differences between IDDM patients and control subjects, but dramatic reductions in baroreceptor-cardiac reflex sensitivity were detected in IDDM patients. 'Up BRS' when supine was 11.2 +/- 1.5 ms/mmHg (mean +/- SEM) compared with 20.4 +/- 1.95 in control subjects (p < 0.003) and when standing was 4.1 +/- 1.9 vs 7.6 +/- 2.7 ms/mmHg (p < 0.001). Down BRS when supine was 11.5 +/- 1.2 vs 22 +/- 2.6 (p < 0.001) and standing was 4.4 +/- 1.9 vs 7.3 +/- 2.5 ms/mmHg (p < 0.003). There were significant relations between impairment of the baroreflex and duration of diabetes (p < 0.001) and poor glycaemic control (p < 0.001). From a fast Fourier transformation of supine heart rate data and using a band width of 0.05-0.15 Hz as low-frequency and 0.2-0.35 Hz as high frequency total spectral power of R-R interval variability was significantly reduced in the IDDM group for both low-frequency (473 +/- 62.8 vs 746.6 +/- 77.6 ms2 p = 0.002) and high frequency bands 125.2 +/- 12.9 vs 459.3 +/- 89.8 ms2 p < 0.0001. When the absolute powers were expressed in normalised units the ratio of low frequency to high frequency power (a measure of sympathovagal balance) was significantly increased in the IDDM group (2.9 +/- 0.53 vs 4.6 +/- 0.55, p < 0.002 supine: 3.8 +/- 0.49 vs 6.6 +/- 0.55, p < 0.001 standing). Thus, time domain analysis of baroreceptor-cardiac reflex sensitivity detects autonomic dysfunction more frequently in IDDM patients than conventional tests. Impaired BRS is associated with an increased left ventricular mass index and this abnormality may have a role in the increased incidence of sudden death seen in young IDDM patients.     

Routine prenatal screening for congenital heart disease: what can be expected? A decision-analytic approach

OBJECTIVES: This study assessed the potential impact of fetal ultrasound screening on the number of newborns affected by cardiac anomalies. METHODS: A decision model was developed that included the prevalence and history of congenital heart disease, characteristics of ultrasound, risk of abortion, and attitude toward pregnancy termination. Probabilities were obtained with a literature survey; sensitivity analysis showed their influence on expected outcomes. RESULTS: Presently, screening programs may prevent the birth of approximately 1300 severely affected newborns per million second-trimester pregnancies. However, over 2000 terminations of pregnancy would be required, 750 of which would have ended in intrauterine death or spontaneous abortion. Further, 9900 false-positive screening results would occur, requiring referral. Only the sensitivity of routine screening and attitude toward termination of pregnancy appeared to influence the yield substantially. CONCLUSIONS: The impact of routine screening for congenital heart disease appeared relatively small. Further data may be required to fully assess the utility of prenatal screening.