Characterization of the complications associated with plasma exchange for thrombotic thrombocytopaenic purpura and related thrombotic microangiopathic anaemias: a single institution experience.

BACKGROUND: Plasma exchange (PEX) is a life-saving therapeutic procedure in patients with thrombotic thrombocytopaenic purpura (TTP) and other thrombotic microangiopathic anaemias (TMAs). However, it may be associated with significant complications, exacerbating the morbidity and mortality in this patient group. STUDY DESIGN AND METHODS: We reviewed all PEX procedures over a 72-month period, following the exclusive introduction of solvent-detergent double viral-inactivated plasma in high-volume users, such as TTP, in the United Kingdom (UK). We documented allergic reactions to plasma, citrate reactions, complications relating to central venous access insertion and venous thrombotic events (VTE) in 155 patient episodes and >2000 PEX procedures. RESULTS: The overall complication rate was low. Allergic plasma reactions occurred in 6·45% of the cohort with only one episode of acute anaphylaxis. Similarly, VTEs were 6·45%, not significantly greater than in medical patients receiving thromboprophylaxis, despite added potential risk factors in TTP. Citrate reactions were the most frequent complication documented, but toxicity was significantly reduced by administration of further calcium infusions during the PEX procedure. There were no serious central line infections and no catheter thrombosis. CONCLUSION: Our data confirms that PEX continues to be a life-saving procedure in the acute TTP setting and, the procedure was not associated with an increased mortality and limited morbidity.

The effect of advanced treatment of sewage effluents on metal speciation and (bio)availability.

The bioavailability of metals can be strongly influenced by dissolved organic carbon (DOC). Wastewater treatment effluents add considerable quantities of DOC and metals to receiving waters, and as effluent controls become more stringent advanced effluent treatments may be needed. We assessed the effects of two types of advanced treatment processes on metal availability in wastewater effluents. Trace metal availability was assessed using diffuse gradients in thin films and predicted through speciation modelling. The results show little difference in metal availability post-advanced treatment. EDTA-like compounds are important metal complexants in the effluents.

Fluorides and the changing prevalence of dental caries.

Community water fluoridation and individual use of fluorides have brought about a marked reduction in the prevalence of dental caries in the United States during the past 35 years. There is evidence that the prevalence of caries is declining in communities with unfluoridated water as well as in those with fluoridated water. This phenomenon may be related to an increase of fluoride in the food chain, especially from the use of fluoridated water in food processing, increased use of infant formulas with measurable fluoride content, and even unintentional ingestion of fluoride dentifrices. This trend should encourage reevaluation of research priorities and previously accepted standards for optimal fluoride use.

Back-up bone marrow is frequently ineffective in patients with poor peripheral-blood stem-cell mobilization.

PURPOSE: To assess hematologic recovery and procedure-related mortality in patients who received high-dose therapy with stem-cell support, in whom the peripheral-blood stem-cell (PBSC) collection fails (CD34+ cells < 1 x 10(6)/kg). The predictive value of granulocyte-monocyte colony-forming cell (GM-CFC) measurements and the value of bone marrow obtained after PBSC collection failure was assessed. PATIENTS AND METHODS: The study group comprised 324 consecutive patients mobilized with granulocyte colony-stimulating factor (G-CSF) and cyclophosphamide (273 patients), G-CSF with other chemotherapy (37 patients), and G-CSF alone (14 patients). Between one and four aphereses were performed. RESULTS: In 51 of 324 patients, there was failure to obtain 1 x 10(6)/kg CD34+ cells. Twenty-three patients had greater than 1 x 10(5)/kg GM-CFC; 22 patients proceeded to high-dose therapy. Neutrophil recovery occurred within 21 days, but platelet independence was delayed (> 28 days) in eight patients. Of 28 patients with less than 1 x 10(5)/kg GM-CFC, six received high-dose therapy with PBSC alone and five had delayed engraftment. Twelve patients with less than 1 x 10(5)/kg GM-CFC received high-dose therapy supported by bone marrow collected after PBSC collection failure. Eleven patients were assessable for engraftment; four patients had slow (> 21 days) or delayed (> 28 days) neutrophil recovery and eight patients had delayed platelet recovery. In the group of patients who received less than 1 x 10(5)/kg GM-CFC, there were five procedure-related deaths. CONCLUSION: This study shows that delayed hematologic recovery is frequent if less than 1 x 10(6)/kg CD34+ cells are infused after high-dose therapy, particularly with GM-CFC less than 1 x 10(5)/kg. The procedure-related mortality in this latter group is high. In most patients whose PBSC collection contains less than 1 x 10(5)/kg GM-CFC, the use of bone marrow cells does not improve engraftment, which suggests that poor PBSC mobilization usually indicates poor marrow function.

Evaluation of clinical scale CD34+ cell purification: experience of 71 immunoaffinity column procedures.

Seventy-one mobilised PBSC collections were subject to CD34+ cell purification using the CEPRATE SC stem cell concentration system. The overall median purity of CD34+ cells was 69% (6-93%). CD34+ cell, and GM-CFC recoveries were 52% (8-107%) and 36% (3-118%). Purity was logarithmically related to the input percentage of CD34+ cells and starting requirements were established of 1% CD34 cell content for optimal purity and a minimum of 2 x 10(6)/kg CD34+ cells to ensure recovery of our minimum engraftment threshold of 1 x 10(6)/kg CD34+ cells. Reduction of the washing steps reduced non-specific cell losses and shortened the procedure but did not affect progenitor cell recovery. Purified CD34+ cells were reinfused following high-dose therapy in 35 patients. The median time to neutrophil recovery of 0.5 x 10(9)/l was 12 (10-23) days and to the attainment of platelet independence was 13 (7-100) days. The risks of delayed platelet recovery were related to the CD34+ cell dose infused and were identical to the risks when non-purified PBSC collections were used. In conclusion, purification of CD34+ cells using the CEPRATE device is reliable and the purified product results in prompt engraftment. The cell losses that occur do however restrict its use in many patients.

Dental caries and staining after twenty-eight months of rinsing with stannous fluoride or sodium fluoride.

The aim of this study was to compare the effects of daily mouthrinsing with aqueous solutions of 0.05% NaF or 0.1% SnF2 on dental caries and tooth staining. The study population consisted of 437 children, aged from 12 to 15 years at baseline, residing in a non-fluoridated community. By stratified random sampling, the subjects were divided into two groups, one group rinsing daily under supervision for 28 months with the NaF solution and the other with the SnF2 solution. The SnF2 group exhibited four to five times as much extrinsic stain as did the NaF group, although the stains were quite mild and not explicitly distinguishable between groups. There were no statistically significant differences between the two groups in terms of total DMFS. However, the increment of pit and fissure caries was 0.9 surfaces fewer for the SnF2 group (p = 0.04), while the increment of smooth surface caries was 0.6 surfaces fewer for the NaF group (p = 0.04). These data suggest that there may be a difference in mechanism of action between SnF2 and NaF rinses.

Effect of daily rinsing with stannous fluoride on plaque and gingivitis: final report.

Two groups of children, ages 12 to 15, rinsed daily for 28 mo with aqueous fluoride solutions, one group using 0.05% sodium fluoride (NaF) and the other group using 0.1% stannous fluoride (SnF2). The SnF2 group had less plaque accumulation after four mo, but no difference was apparent at 16 and 28 mo. Gingivitis was less severe in the SnF2 group throughout the study, although the difference did not reach statistical significance. The 0.1% SnF2 solution, used daily as a mouthrinse, inhibits plaque formation, although this inhibitory effect is not apparent after 16 mo of rinsing.

The effect of daily mouthrinsing with stannous fluoride on dental plaque and gingivitis--four-month results.

This clinical trial of a daily 0.1% SnF2 mouthrinse involved over 400 children, from 12 to 15 years of age. With 0.05% NaF as the active control, rinsing was conducted daily for four mo after baseline examinations. Four-month examinations showed significantly lower Plaque Index scores for the SnF2 group. Gingival Index scores for the SnF2 group were lower, but did not reach statistical significance.

Caries risk assessment in a longitudinal discrimination study.

Our objective was to develop and perfect a model for the assessment of risk of dental caries onset in children. Even though dental caries prevalence in children is continuing to decline, there is still a significant minority for whom it is a problem. In this study, we sought to ascertain whether a set of variables selected in a previous cross-sectional study could be used to differentiate between caries-free six-year-olds who would or would not subsequently present with clinically-detectable caries. A total of 472 caries-free six-year-olds--286 from a fluoridated community and 186 from a fluoride-deficient community--was selected. Clinical examinations for DMFS, dental fluorosis, and plaque were conducted. Stimulated whole saliva was collected for analysis of mutants streptococci, lactobacilli, total viable flora, and fluoride, calcium, and phosphate concentrations. A questionnaire was used for collection of demographic data as well as information on prior fluoride exposure, dietary habits, and oral hygiene practices. By means of linear discriminant analyses, it was possible to predict correctly which children would develop caries within six to 12 months (sensitivity) in 82.8% of cases and which children would not develop caries during that period (specificity) in 82.4% of cases.

Caries risk assessment by a cross-sectional discrimination model.

Although the prevalence of dental caries is continuing to decline, it still affects a majority of the US population and can be a serious problem for those afflicted. The objective of this project was to develop and perfect a model for assessment of risk of dental caries onset in children. In the first study, reported herein, a set of clinical, microbiological, biochemical, and socio-demographic variables was identified that distinguished, with an acceptable level of sensitivity and specificity, between children who had no previous caries experience and children who had high caries levels. A total of 313 children--age 12-15 years, 140 from a fluoridated community and 173 from a fluoride-deficient community--was selected on the basis of previous caries experience, either zero DMFS or high DMFS (> or = 6 in the fluoridated or > or = 8 in the fluoride-deficient community). Clinical exams for DMFS, dental fluorosis, and plaque were conducted. Stimulated whole saliva was collected for analysis of mutans streptococci, lactobacilli, total viable flora, and fluoride concentration. A questionnaire was used for collection of demographic data as well as information on prior fluoride exposure, dietary habits, and oral hygiene practices. By means of discriminant analyses, with use of seven key clinical and laboratory variables, it was possible for zero-DMFS subjects to e classified correctly (specificity) in 77.6% of cases in the fluoridated community and in 86.1% of cases in the fluoride-deficient community. High-caries subjects were classified as such (sensitivity) in 79.3% and 88.1% of cases, respectively.

A computerized system for the evaluation of community dental programs.

This paper reports on a relatively uncomplicated and inexpensive computerized system for prospective evaluation of clinical dental programs from the point of view of effectiveness and efficiency. Availability of this system does away with some high start-up costs. Three forms of input data, new case information, examination findings and operative procedure information, are regularly collected on data sheets and specially designed Port-a-punch IBM cards. Easily interpreted output tables are generated monthly on such variables as completed cases according to treatment series and clinician, number of various procedures performed by clinicians, etc. Productivity is measured, in part, by application of monetary constants to procedure data. This paper describes the computer programs used, the cost of setting up and operating the system (which is within the budgetary constraints of most small, publicly funded programs) and the benefits that can be derived from the use of such a system. The system provides prompt feedback of relevant administrative data, thus allowing for relatively quick response to problems. Use of the system reduces clerical needs to a minimum and the program can easily be implemented on any except the very smallest digital computer.

Retention of sealants over carious and sound tooth surfaces.

Bacteriologic and clinical studies suggest that sealants can be used therapeutically on incipient caries of the enamel. The present study was designed to explore this approach further by determining whether there is a difference in retention rates on sound or carious tooth surfaces sealed for the first time as well as resealed surfaces. A total of 1766 teeth were sealed for subjects 12-14 yr of age of which 120 were judged to be carious. Mouths were divided sagittally on a random basis and an ultraviolet light activated resin with a filler or an autopolymerizing resin without a filler was placed on contralateral surfaces of all molar and premolar teeth. The effects of sealant type, caries status, arch and tooth type on retention over a 2-yr period were tested using Mantel-Haenszel statistics. At the end of 1 yr, 88% of the teeth sealed with the autopolymerizing resin were judged to be completely intact compared to 82% of the teeth filled with the ultraviolet light resin. At the end of the second year the retention rates were 84% and 75% respectively. The retention rates for carious and sound teeth at the end of both years were almost identical. Overall, premolars had a 15% more favorable retention rate than molars. There were minimal differences between arches although maxillary premolars had approximately a 5% higher retention rate than mandibular premolars. The reverse was true for molar teeth. Retention of sealants at the end of the second year (resealed after 1 yr) was 4% less than comparable teeth sealed initially.

Prevalence of dental fluorosis in fluoridated and nonfluoridated communities--a preliminary investigation.

As a result of undocumented observations that the prevalence of dental fluorosis in both fluoridated and nonfluoridated communities may be higher than would be predicted on the basis of Dean's data from the 1940s, dental fluorosis assessments using a modification of Dean's Index were made in 1981 as part of routine examinations in a series of clinical trials. A total of 1,663 children in fluoridated or nonfluoridated communities, ranging in age from seven to 17 years, were examined during 1981-82. The prevalence of dental fluorosis in nonfluoridated communities ranged from 1.7 percent in 16-year-olds to 13.9 percent in 10-year-olds and, in fluoridated communities, ranged from 17.1 percent in 13-year-olds to 33.0 percent in 14-year-olds. At all age levels common to the two types of communities, the difference in prevalence of dental fluorosis was statistically significant. Compared with findings in Dean's studies in 1942, for children of comparable age in communities with essentially the same water-fluoride levels, the prevalence of dental fluorosis in the present study was 3 1/2 times higher in nonfluoridated communities and two times higher in fluoridated communities. Mean fluorosis scores, however, were similar. If additional studies substantiate that the prevalence and intensity of dental fluorosis are increasing, the accepted norms for fluoride dosage need to be reassessed--especially in supplements, dentifrices, and water.

Effectiveness of mouthrinsing with fluoride solutions in preventing coronal and root caries.

Fluoride mouthrinses have been used extensively for the past 15 years to prevent dental caries in children. Their use has been especially widespread in organized school-based programs in the US. Nearly three dozen clinical studies of fluoride mouthrinses, both with and without placebo controls, have been reported in the literature since the early 1960s. The overwhelming majority of those studies report statistically significant caries inhibition from the use of the products. Most of the studies were published prior to the knowledge of a decline in caries prevalence during the past 30 years. Consequently, the results of those studies lacking a placebo control group have been challenged. Even randomized clinical trials with appropriate control groups appear to be reporting declining differences between test and control groups. Using a model based on annual caries increments from published studies, the conclusion is reached that future use of fluoride mouthrinses is unlikely to result in annual savings in DMF increment greater than 0.4 surfaces, regardless of age of rinsers.

Weekly rinsing with a fluoride mouthrinse in an unfluoridated community: results after seven years.

In the fall of 1975, 1,915 children in grades K through eight began a school-based program of supervised weekly rinsing with 0.2 percent aqueous solution of sodium fluoride in an unfluoridated community in the Finger Lakes area of upstate New York. At baseline and annually thereafter, a random sample of children in grades K through 11 received clinical dental caries examinations. The prevalence of dental caries by grade at each of the follow-up dental examinations was compared to the grade-specific prevalence of dental caries at baseline. Overall, there was a decline of 57.8 percent in prevalence of caries in permanent teeth after seven years of rinsing. Among children in grades K through five, there was a decline of 35.4 percent in the prevalence of caries in primary teeth during the same time period. Tenth and eleventh grade children, after not rinsing for one and two years, respectively, continued to show the same trend toward lower caries prevalence as active rinsers. Caries prevalence among seventh and eighth graders after seven years of rinsing was not significantly different from caries prevalence among seventh and eighth grade lifetime residents of a nearby fluoridated community. A decline in the prevalence of caries in primary teeth among kindergartners prior to rinsing suggests that factors in addition to the mouthrinse program may have contributed to the decline in caries prevalence.

Clinical radiographic evaluation of sealed carious and sound tooth surfaces.

The results of a 2-year radiographic assessment of 113 carious posterior teeth that were sealed with one of two sealants are presented. Little or no difference was found in radiographic ratings of caries by type of sealant. Sealant loss between annual recall visits had little or no detectable effect on radiographic ratings of caries during the study. Radiographs suggested that caries may regress in sealed teeth with early caries. The results support the safety of sealing incipient caries in pits and fissures to increase the potential uses of sealants.

Variables affecting attitudes of dentists toward the use of expanded function auxiliaries.

A questionnaire survey of over 500 dentists in upstate New York was conducted to determine the following: (1) the extent to which the dentists understood the recent changes in the State Dental Practice Act as it applies to expanded functions of dental hygienists and (2) the attitudes and beliefs of these dentists regarding the use of hygienists and dental assistants in the performance of expanded duties in the private office. In general, the respondents were not familiar with the recent changes in the Dental Practice Act. When the respondents who employed dental hygienists were compared to those who did not employ hygienists, the differences regarding understanding of the changes in the act were not striking.