In vitro polishing effectiveness of interdental aids on root surfaces

The purpose of this study was: to determine whether polishing standardized proximal root surfaces with dental floss, Superfloss, wood and plastic interdental cleaners, using a polishing paste, produces any significant change on root surface roughness; and to determine the effectiveness of different number of strokes in polishing. 80 tooth specimens were prepared, 10 in each of 8 sample groups. Each proximal root surface was standardized with 600A grit silicone carbide paper and polished with either waxed dental floss, Superfloss, wood or plastic interdental cleaners, using alkali aluminum silicate polishing paste. All specimens were mounted on a flossing machine and polished with 10 or 20 strokes. Before and after polishing, measurements were recorded with the Surfanalyzer 150 System to produce profile and average roughness tracings. Average maximum peak heights, mean number of peaks, and mean average roughness values were calculated from the tracings. The data were analyzed statistically by paired t-test and Student t-test. No significant mean differences were found between the number of strokes used. No significant differences were found for waxed dental floss in relation to the values analyzed. Significant differences were found for maximum peak heights for Superfloss following 20 strokes of polishing. However, no significant differences were found for Superfloss for mean number of peaks and average roughness. Significant differences were found for average roughness values, maximum peak heights, and mean number of peaks for the wood and plastic interdental cleaners. It was concluded that root surface roughness increased significantly with the use of wood and plastic interdental cleaners but not with waxed dental floss or Superfloss.     

Neonates with hypoplastic left heart syndrome have ultrasound evidence of abnormal superior mesenteric artery perfusion before and after modified Norwood procedure.

OBJECTIVE: To a) describe superior mesenteric artery resistive index, as an estimate of perfusion, before and after modified Norwood; and b) assess incidence of diastolic flow reversal in the superior mesenteric artery before and after modified Norwood. DESIGN: Prospective observational trial. SETTING: Children's hospital pediatric intensive care unit. PATIENTS: Ten newborns with hypoplastic left heart syndrome. INTERVENTIONS: Ultrasound documentation of superior mesenteric artery diastolic flow direction and measurement of superior mesenteric artery resistive index 24-48 hrs before and 24-48 hrs after modified Norwood. MEASUREMENTS AND MAIN RESULTS: Seven males and three females were enrolled. There was no change between the superior mesenteric artery resistive index pre- vs. postoperatively-0.99 (95% confidence interval, 0.85, 1.12) vs. 1.07 (95% confidence interval, 1.0, 1.15) (p = .13). Incidence of retrograde diastolic blood flow in the superior mesenteric artery was not different pre- vs. postoperatively (70% vs. 50%, p = .41). No patients developed necrotizing enterocolitis and all survived to hospital discharge. CONCLUSIONS: Ultrasound measurements in neonates with hypoplastic left heart syndrome suggest that superior mesenteric artery perfusion, as measured by resistive index, is impaired. Superior mesenteric artery diastolic flow reversal is common before and immediately after modified Norwood.     

Quality of vision through diffractive bifocal intraocular lenses.

Two elderly women have each received a monofocal intraocular lens in one eye and a 3M diffractive bifocal intraocular lens in the other eye. Both eyes were shown to have equivalent retinal/neural function by measuring contrast sensitivity to laser interference fringes which bypassed refractive and other defects of the ocular media. The eyes with a bifocal intraocular lens displayed a much greater depth of focus, though at the expense of diminished contrast sensitivity compared with the normal values expected for that age. Simulation experiments suggested that the observed reduction in contrast sensitivity was not adequately explained by a simple reduction in retinal illumination of the in-focus image as might intuitively be expected from the bifocal separation of incident light to two simultaneous focal points. The simultaneous superimposition of the out-of-focus image on the in-focus image must also be considered, since this caused a significant reduction in contrast sensitivity when the retinal illumination was insufficiently above the photopic luminance threshold.     

Modification of renal cortical subcellular membrane phospholipids induced by mercuric chloride

Administration of mercuric chloride (HgCl2, 6 mg/kg) to rabbits produced renal failure, with changes in serum creatinine from 1.01 +/- 1 in controls to 6.46 +/- 0.91 mg/dl 24 hr after administration. Mitochondria isolated from HgCl2-treated rabbits exhibited alterations in acceptor control ratios, with reduction to 1.9 +/- 0.2 from 3.9 +/- 1.2 in controls. Ultrastructurally, the mitochondria showed swelling and loss of inner mitochondrial membranes. Total lipids from mitochondria of control and treated rabbits were obtained by modified Folch extraction and phospholipids analyzed by TLC. Brush border membranes and basolateral membranes were prepared from control and HgCl2-treated kidneys 2 and 24 hr after HgC12 administration. At 24 hr mitochondria showed a 36% fall in phosphatidylcholine (PC), a 36% fall in phosphatidylethanolamine (PE), and a 27% fall in cardiolipin. Brush border showed a decrease in phosphatidylserine (PS) of 29% and in PE of 40%. The basolateral membranes showed a reduction only in PE of 35%. At 2 hr post HgCl2, early changes are confined to the BBM and consist of a reduction in PE in this membrane. This changes in membrane phospholipids may be important in the functional derangements that occur at the cellular level after HgCl2 administration.     

Regional heterogeneity in the distribution of somatostatin-28- and somatostatin-28(1-12)-immunoreactive profiles in monkey neocortex

The distribution of the prosomatostatin-derived peptides (PSDP), somatostatin-28 and somatostatin-28(1-12), in the cynomolgus monkey (Macaca fascicularis) neocortex was characterized in quantitative immunohistochemical studies of 3 visual areas (V1, primary visual cortex; V2, the adjacent visual association area; and AIT, a visual association area in anterior inferior temporal cortex), 2 auditory areas (AI, primary auditory cortex; and T1, an adjacent auditory association area) and anterior cingulate cortex (Area 24). The results of similar quantitative analyses in 3 homologous areas in rat neocortex (primary visual, primary auditory, and anterior cingulate) are also presented. Primate cortical areas differed significantly in both density and laminar distribution of PSDP-immunoreactive profiles. Area 24, the most densely labeled area, had nearly 6 times as many PSDP-immunoreactive neurons as V1. Both auditory areas contained approximately two-thirds the number of PSDP-immunoreactive neurons found in Area 24; however, both had nearly 4 times as many immunoreactive neurons as V1. The 3 visual areas showed incremental increases in the number of PSDP-immunoreactive neurons; V2 contained nearly twice and AIT nearly 3 times the number of immunoreactive neurons present in V1. Both the supra- and infragranular layers were densely labeled in Area 24 and Area T1, however, in AI, V1, V2, and AIT the infragranular layers were relatively sparsely labeled. In contrast to the regional heterogeneity found in the primate neocortex, the distribution of immunoreactive neurons was quite uniform across the 3 rat cortical areas. The rat cortical areas contained substantially fewer immunoreactive neurons than most of the monkey cortical areas, and a majority of these immunoreactive neurons were located in the infragranular layers. These findings suggest that the regional specialization of primate neocortex involves the selective distribution of PSDP-immunoreactive neurons. They also suggest that chemically specified intrinsic organization of neocortex is not likely to be uniform across species or across cortical areas in the primate. The distinctive regional distribution patterns of PSDP-immunoreactive profiles appear to parallel that of the long corticocortical projections (contralateral and distant ipsilateral projections), suggesting an association between these presumed inhibitory interneurons and this important extrinsic system.     

Cloning and sequencing of a t(14;19) breakpoint that involves the Cμ switch region

The t(14;19) is a recurring translocation found in a small number of cases of chronic B-cell leukemia (CLL). We have cloned and sequenced the breakpoint in a patient with a t(14;19) and shown that the breakpoint on chromosome 14 occurred in the Cμ switch region, and that the breakpoint on chromosome 19 occurred in the 5′ untranslated region of the BCL3 gene. This is in contrast to all the other reported cases with a t(14;19) in which the breakpoints on chromosome 14 occurred in the Cαl or Cα2 switch region, and the breakpoints on chromosome 19 occurred upstream of the BCL3 gene. Our results further emphasize the importance of the switch region in the t(14;19) translocation. © 1993 Wiley-Liss, Inc.     

Prediction of outcome in congenital diaphragmatic hernia

The case records of 59 patients with congenital diaphragmatic hernia (CDH) who presented between 1984 and 1997 were studied retrospectively. Included in the study were infants born with CDH who required respiratory support within the first 6 h of life. Twenty-three were excluded from the study for various reasons; 36 were enrolled in the study; the male-to-female ratio was 18:18. Twenty-nine hernias were left-sided and 7 were right-sided. All patients were ventilated using conventional techniques. Arterial blood gases were measured on average 1.76 h following admission and the initial period of resuscitation (range 1–4 h). Three formulae were applied in an attempt to predict outcome: ventilation index against PCO₂, alveolar-arterial oxygen gradient, and a newly derived formula from this institution (Red Cross formula) that comprises respiratory rate × PCO₂× FiO₂× mean airway pressure/PaO₂× 6000. Seventeen patients (47.2%) survived and 19 died (52.8%); 21 became stable enough to undergo surgery. The average time from presentation until surgery was 1.98 days (range 6 h to 4 days). The Red Cross formula, with a 100% predictive value for mortality, 85% predictive value for survival, and an overall predictive value of 91.6%, appeared to be superior to the other formulae studied. The availability of a highly accurate predictive formula may facilitate management of this frequently lethal disease. Accepted: 6 March 1998     

Current perspectives on glycopeptide resistance.

In the last 5 years, clinical isolates of gram-positive bacteria with intrinsic or acquired resistance to glycopeptide antibiotics have been encountered increasingly. In many of these isolates, resistance arises from an alteration of the antibiotic target site, with the terminal D-alanyl-D-alanine moiety of peptidoglycan precursors being replaced by groups that do not bind glycopeptides. Although the criteria for defining resistance have been revised frequently, the reliable detection of low-level glycopeptide resistance remains problematic and is influenced by the method chosen. Glycopeptide-resistant enterococci have emerged as a particular problem in hospitals, where in addition to sporadic cases, clusters of infections with evidence of interpatient spread have occurred. Studies using molecular typing methods have implicated colonization of patients, staff carriage, and environmental contamination in the dissemination of these bacteria. Choice of antimicrobial therapy for infections caused by glycopeptide-resistant bacteria may be complicated by resistance to other antibiotics. Severe therapeutic difficulties are being encountered among patients infected with enterococci, with some infections being untreatable with currently available antibiotics.