Studies on the binding of lipoteichoic acid to osseous tissue

Tritium-labelled lipoteichoic acid (³H-LTA) was examined for its interaction with connective tissue components by employing autoradiography. Evidence was obtained for LTA binding to both the calcified matrix and to cells of neonatal rat parietal and long bones in vitro . The interaction of LTA with bone-derived cells was studied in a model system utilizing an osteosarcoma cell line in tissue culture. These tumour cells incorporated ³H-LTA as long as they were actively dividing but deacylated LTA was not incorporated. This suggested that the lipid portion of the molecule was necessary for interaction with the cells. Evidence has also been obtained for an interaction of LTA with components from the culture fluid of osteosarcoma cells.     

Enumeration of oral streptococci on media containing different concentrations of sodium and potassium ions

Laboratory "type" strains of oral streptococci were screened for their ability to grow on mitis-salivarius agar (MSA) in the presence of increasing concentrations of either Na+ or K+ up to 500 mmol/L. Strains were generally better able to withstand increasing concentrations of Na+ than K+, although low numbers of colony-forming units (cfus) were seen with the highest concentration of either cation. Two strains of Streptococcus mutans, Ingbritt 162 and Ingbritt 175, behaved differently when the concentration of cation was increased from 50 to 200 mmol/L; the latter showed a marked increase in the number of cfus when the Na+ concentration was increased from 50 to 200 mmol/L, whereas there was a decrease with strain Ingbritt 162. Strains of oral streptococci from the saliva of adults and children were isolated on modified MSA containing known concentrations of Na+ and K+ and further examined if they showed "mutans-like" colony morphology. The number of cfus generally dropped as the concentration of Na+ or K+ was increased from 200 to 350 or 500 mmol/L. Greater numbers of streptococci were tolerant to Na+ than to K+. Half of the isolates were members of the Streptococcus sanguis group (SSG), either Streptococcus mitis or S. sanguis II, and these were more tolerant to high concentrations of Na+ or K+ than other isolates that were identified as Streptococcus morbillorum, Streptococcus acidominimus, and Streptococcus milleri.     

Characteristics of ''best'' and ''worst'' clinical teachers as perceived by university nursing faculty and students

This study identified and compared characteristics of 'best' and 'worst' clinical teachers as perceived by university nursing faculty and students. The Nursing Clinical Teacher Effectiveness Inventory (NCTEI) was distributed to 201 volunteer subjects. This survey instrument, developed by the authors, contains 48 clinical teacher characteristics grouped into five categories. Each participant was asked to rate, using the NCTEI, the 'best' and them the 'worst' clinical teacher from past observations. Results showed both groups perceived that being a good role model was the highest rated characteristic for 'best' teachers and the 'lowest' rated characteristic for 'worst' teachers. Faculty and students' perceptions were fairly similar as to highest rated characteristics of 'best' clinical teachers. Less agreement was noted about the characteristics of 'worst' clinical teachers. When categories of clinical teacher characteristics were compared, there were significant differences between the ratings of faculty and students for 'best' clinical teachers, but none for 'worst' clinical teachers.     

Mechanism of resistance to the phosphaturic effect of the parathyroid hormone in the hamster.

The effect of parathyroid hormone and calcitonin on the renal excretion of phosphate, calcium, and cyclic AMP was evaluated in the thyroparathyroidectomized hamster, a mammal apparently reisstant to the phosphaturic effect of parathyroid hormone. Parathyroid hormone did not increase phosphate excretion, although it decreased excretion of calcium and increased urinary excretion of cyclic AMP. This lack of a phosphaturic response to parathyroid hormone was not reversed by administration of 25-OH vitamin D or infusions of calcium or phosphate. Calcitonin, another potentially phosphaturic hormone, also vailed to increase phosphate excretion but markedly elevated urinary excretion of cyclic AMP. In hamsters pretreated with infusion of urinary ammonium chloride, which decreased plasma and urinary pH, both parathyroid hormone and calcitonin increased excretion of phosphate as well as that of cyclic AMP. Acetazolamide had no phosphaturic effect in ammonium chloride-loaded hamsters, and it decreased cyclic AMP and calcium excretion. Alkalinization of urine by acetazolamide did not prevent the phosphaturic effect of parathyroid hormone in ammonium chloride-loaded hamsters, but it blocked the increase in urinary cyclic AMP excretion. Parathyroid hormone and calcitonin both stimulated adenylate cyclase in a cell-free system (600-g pellet) from hamster renal cortex, elevated tissue cyclic AMP levels, and activated protein kinase in tissue slices from hamster renal cortex. In acid medium, the increase in cyclic AMP and activation of protein kinase in response to parathyroid hormone was diminished, but addition of acetazolamide restored responsiveness of both parameters to control values. Acetazolamide, on the other hand, did not influence adenylate cyclase or its response to parathyroid hormone or cyclic AMP phosphodiesterase activity. We conclude that the lack of a phosphaturic effect of parathyroid hormone and calcitonin in the hamster depends on steps in the cellular action of these hormones, steps that are sensitive to pH subsequent to cyclic AMP generation and protein kinase activation. In addition, acetazolamide may potentiate the phosphaturic effect of parathyroid hormone by promoting accumulation of cyclic AMP in tissue. Thus, the hamster is a particularly useful model for studies of syndromes in which there is renal resistance to phosphaturic hormones.     

Effect of increased peritubule protein concentration on proximal tubule reabsorption in the presence and absence of extracellular volume expansion.

The effect of increased peritubule capillary oncotic pressure on sodium reabsorption by the proximal tubule of the dog was investistigated after extracellular volume expansion (ECVE) with Ringer's solution or during continued hydropenia. Control measurements were made after ECVE or during hydropenia and again during renal arterial infusion with hyperoncotic albumin solution. Absolute reabsorption by the proximal tubule was calculated from fractional reabsorption and single nephron filtration rates as determined by micropuncture. Direct measurements of efferent arteriole protein were used to determine efferent arteriolar oncotic pressure. Albumin infused into the renal artery after ECVE significantly increased efferent oncotic pressure by 17.6 plus or minus 5.3 mm Hg. Fractional and absolute reabsorption by the proximal tubule increased from 20 plus or minus 6 to 37 plus or minus 5% and from 22 plus or minus 6 to 36 plus or minus 7 nl/min, respectively. During hydropenia, the albumin infusion significantly increased efferent oncotic pressure by 15.0 plus or minus 4.4 mm Hg. However, in contrast to the effect seen during ECVE, neither fractional nor absolute reabsorption was changed, delta equals 0.3 plus or minus 1.5% and 3 plus or minus 5 nl/min, respectively. Single nephron filtration rates were not significantly different between the groups and were unchanged by the albumin infusion. Peritubule capillary hydrostatic pressures, measured with a null-servo device, were not changed by the albumin infusion in either group. Renal interstitial hydrostatic pressure, measured from chronically implanted polyethylene capsules, was decreased significantly from 7.2 plus or minus 0.9 to 3.4 plus or minus 0.6 mm Hg in the hydropenic group and from 0.6 plus or minus 0.6 to 4.8 plus or minus 0.7 mm Hg in the Ringer's expanded group. In the hydropenic group, the increase in efferent oncotic pressure was nearly compensated for by changes in interstitial forces so that the calculated net force for capillary uptake was almost unchanged, 17.8 mm Hg before vs. 21.4 mm Hg during the albumin infusion. The increased efferent oncotic pressure in the Ringer's expanded group was not compensated, so that the calculated net force for uptake was increased, 11.9 mm Hg before to 22.2 mm Hg during the albumin infusion. Thus, while the increase in efferent oncotic pressure during albumin infusion was not significantly different between the groups, absolute and fractional reabsorptions were increased only in the animals in which the extracellular volume was expanded. The results suggest that ECVE alters the effect of increased peritubule oncotic pressure on sodium reabsorption by the proximal tubule.     

A Biomechanical Comparison of Fiberglass Casts and 3-Dimensional–Printed,Open-Latticed,Ventilated Casts

Background: The aim of this study was to quantify the stabilizing properties of a 3-dimensional (3D)-printed short-arm cast and compare those properties with traditional fiberglass casts in a cadaveric subacute distal radius fracture model. Methods: A cadaveric subacute fracture model was created in 8 pairs of forearms. The specimens were equally allocated to a fiberglass cast or 3D-printed cast group. All specimens were subjected to 3 biomechanical testing modalities simulating daily life use: flexion and extension of digits, pronation and supination of the hand, and 3-point bending. Between each loading modality, radiological evaluation of the specimens was performed to evaluate possible interval displacement. Interfragmentary motion was quantified using a 3D motion-tracking system. Results: Radiographic assessment did not reveal statistically significant differences in radiographic parameters between the 2 groups before and after biomechanical testing. A statistically significant difference in interfragmentary motion was calculated with the 3-point bending test, with a mean difference of 0.44 (±0.48) mm of motion. Conclusions: A statistically significant difference in interfragmentary motion between the 2 casting groups was only identified in 3-point bending. However, the clinical relevance of this motion remains unclear as the absolute motion is less than 1 mm. The results of this study show noninferiority of the 3D-printed casts compared with the traditional fiberglass casts in immobilizing a subacute distal radius fracture model. These results support the execution of a prospective randomized clinical trial comparing both casting techniques.     

Evaluation of poststreptococcal illness

Group A beta-hemolytic streptococcal pharyngitis, scarlet fever, and rarely asymptomatic carrier states are associated with a number of poststreptococcal suppurative and nonsuppurative complications. As in streptococcal pharyngitis, acute rheumatic fever, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection, and poststreptococcal glomerulonephritis most often occur in children. The hallmarks of rheumatic fever include arthritis, carditis, cutaneous disease, chorea, and subsequent acquired valvular disease. Pediatric autoimmune neuropsychiatric disorders encompass a subgroup of illnesses involving the basal ganglia in children with obsessive-compulsive disorders, tic disorders, dystonia, chorea encephalitis, and dystonic choreoathetosis. Poststreptococcal glomerulonephritis is most frequently encountered in children between two and six years of age with a recent history of pharyngitis and a rash in the setting of poor personal hygiene during the winter months. The clinical examination of a patient with possible poststreptococcal complications should begin with an evaluation for signs of inflammation (i.e., complete blood count, erythrocyte sedimentation rate, C-reactive protein) and evidence of a preceding streptococcal infection. Antistreptolysin O titers should be obtained to confirm a recent invasive streptococcal infection. Other important antibody markers include antihyaluronidase, antideoxyribonuclease B, and antistreptokinase antibodies.     

Clients' perspectives on therapy termination

Abstract

We used consensual qualitative research to analyze interviews with 12 clients about their termination from psychotherapy. Those who had positive termination experiences reported a strong therapeutic relationship and positive outcomes of therapy. They terminated primarily for logistical or financial reasons; their termination, post-termination plans, and feelings about termination were discussed in advance with their therapist, as was their growth in therapy, leading to mostly positive effects of the termination. In contrast, those who had problematic terminations reported a mixed therapeutic relationship and mixed outcomes of therapy. They usually terminated abruptly because of a therapeutic rupture, and thus termination was rarely planned and discussed in advance, rendering it a negative experience. Implications of these findings are addressed.     

Two BRM promoter polymorphisms predict poor survival in patients with hepatocellular carcinoma

Polymorphisms in the promoter of the BRM gene, a critical subunit of the chromatin remodeling SWI/SNF complex, have previously been implicated in risk and prognosis in Caucasian‐predominant lung, head and neck, esophageal, and pancreatic cancers, and in hepatocellular cancers in Asians. We investigated the role of these polymorphisms in hepatocellular carcinoma (HCC) risk and prognosis. HCC cases were recruited in a comprehensive cancer center while the matched controls were recruited from family practice units from the same catchment area. For risk analyses, unconditional logistic regression analyses were performed in HCC patients and matched healthy controls. Overall survival analyses were performed using Cox proportional hazard models, Kaplan‐Meier curves, and log‐rank tests. In 266 HCC cases and 536 controls, no association between either BRM promoter polymorphism (BRM‐741 or BRM‐1321) and risk of HCC was identified (P > 0.10 for all comparisons). There was significant worsening of overall survival as the number of variant alleles increased: BRM‐741 per variant allele adjusted hazards ratio (aHR) 5.77, 95% confidence interval (CI) 2.89‐11.54 and BRM‐1321 per variant allele aHR 4.09, 95%CI 2.22‐7.51. The effects of these two polymorphisms were at least additive, where individuals who were double homozygotes for the variant alleles had a 45‐fold increase in risk of death when compared to those who were double wild‐type for the two polymorphisms. Two BRM promoter polymorphisms were strongly associated with HCC prognosis but were not associated with increased HCC susceptibility. The association was strongest in double homozygotes for the allele variants.