How has research on the effectiveness and safety of COVID-19 vaccination been evaluated: a scope review with emphasis on CoronaVac

Introduction

The control of the COVID-19 epidemic has been focused on the development of vaccines against SARS-CoV-2. All developed vaccines have reported safety and efficacy results in preventing infection and its consequences, although the quality of evidence varies depending on the vaccine considered. Different methodological designs have been used for their evaluation, which can influence our understanding of the effects of these interventions. CoronaVac is an inactivated vaccine, and it has been assessed in various studies, including clinical trials and observational studies. Given these differences, our objective was to explore the published information to answer the question: how has the efficacy/effectiveness and safety of CoronaVac been evaluated in different studies? This is to identify potential gaps and challenges to be addressed in understanding its effect.

Methods

A scoping review was carried out following the methodology proposed by the Joanna Briggs Institute, which included studies carried out in humans as of 2020, corresponding to systematic reviews, clinical trials, analytical or descriptive observational studies, in which the effectiveness and/or safety of vaccines for COVID19 were evaluated or described. There were no age restrictions for the study participants.

Results

The efficacy/effectiveness and safety of this vaccine was assessed through 113 studies. Nineteen corresponded to experimental studies, 7 of Phase II, 5 of Phase IV, and 4 were clinical trials with random assignment. Although some clinical trials with random assignment have been carried out, these have limitations in terms of feasibility, follow-up times, and with this, the possibility of evaluating safety outcomes that occur with low frequencies. Not all studies have used homogeneous methods of analysis. Both the prevention of infection, and the prevention of outcomes such as hospitalization or death, have been valued through similar outcomes, but some through multivariate analysis of dependencies, and others through analysis that try to infer causally through different control methods of confounding.

Conclusion

Published information on the evaluation of the efficacy/effectiveness and safety of the CoronaVac is abundant. However, there are differences in terms of vaccine application schedules, population definition, outcomes evaluated, follow-up times, and safety assessment, as well as non-standardization in the reporting of results, which may hinder the generalizability of the findings. It is important to generate meetings and consensus strategies for the methods and reporting of this type of studies, which will allow to reduce the heterogeneity in their presentation and a better understanding of the effect of these vaccines.

Association of Circulating Tumor Cells and Tumor Molecular Profile With Clinical Outcomes in Patients With Previously Untreated Metastatic Colorectal Cancer: A Pooled Analysis of the Phase III VISNÚ-1 and Phase II VISNÚ-2 Randomized Trials

BACKGROUND

The bCTC count is a well-established prognostic biomarker in mCRC, as well as in other tumor types. The aim of this analysis was to evaluate the prognostic/predictive role of the bCTC count (≥3 vs. <3) in previously untreated mCRC.

PATIENTS AND METHODS

The study involved 589 untreated mCRC patients included in the intention-to-treat population of 2 randomized clinical trials (phase III VISNU-1 [NCT01640405] and phase II VISNU-2 [NCT01640444] studies).

RESULTS

Of the 589 patients, 349 (59.2%) had bCTC≥3 and 240 (40.7%) had bCTC<3. Multivariate analysis showed that the bCTC count is an independent prognostic factor for overall survival (OS) (HR 0.59, 95% CI 0.48-0.72; P = 0.000) and potential for progression-free survival (PFS) (P = 0.0549). Median OS was 32.9 and 19.5 months in patients with bCTC<3 and bCTC≥3 (P <0.001), respectively. This effect was also observed comparing OS in RASwt patients from both studies. Other prognostic factors were: ECOG-PS, primary tumor site, number of metastatic sites and surgery of the primary tumor. Median OS was lower for patients treated with anti-VEGF versus anti-EGFR (22.3 vs. 33.3 months, P <0.0001) while there were no significant differences in PFS according to the targeted treatment received.

CONCLUSION

This post-hoc analysis of 2 randomized studies confirms the poor prognosis of patients with bCTC≥3 but this is not associated with other adverse independent prognostic factors such as RAS/BRAF mutations.

Influence of BRAF and PIK3CA mutations on the efficacy of FOLFIRI plus bevacizumab or cetuximab as first-line therapy in patients with RAS wild-type metastatic colorectal carcinoma and <3 baseline circulating tumour cells: the randomised phase II VISNÚ-2 study

Background

We explored the influence of BRAF and PIK3CA mutational status on the efficacy of bevacizumab or cetuximab plus 5-fluorouracil/leucovorin and irinotecan (FOLFIRI) as first-line therapy in patients with RAS wild-type metastatic colorectal cancer (mCRC).

Patients and methods

VISNÚ-2 was a multicentre, randomised, phase II study. Patients with RAS wild-type mCRC and <3 circulating tumour cells/7.5 ml blood were stratified by BRAF/PIK3CA status (wild-type versus mutated) and number of affected organs (1 versus >1), and allocated to bevacizumab (5 mg/kg every 2 weeks) or cetuximab (400 mg/m² then 250 mg/m² weekly) plus FOLFIRI [irinotecan 180 mg/m², leucovorin 400 mg/m², 5-fluorouracil 400 mg/m² (bolus) then 2400 mg/m² (46-h continuous infusion) every 2 weeks]. The primary endpoint was progression-free survival (PFS). All analyses were exploratory.

Results

Two hundred and forty patients with BRAF/PIK3CA wild-type (n = 196) or BRAF- and/or PIK3CA-mutated tumours (n = 44) were enrolled. Median PFS was 12.7 and 8.8 months in patients with BRAF/PIK3CA wild-type and BRAF/PIK3CA-mutated tumours, respectively [hazard ratio (HR) = 1.22; 95% confidence interval (CI) 0.80-1.85; P = 0.3602]. In the BRAF- and/or PIK3CA-mutated cohort, median PFS was 2.8, 8.8 and 15.0 months in patients with BRAF/PI3KCA-mutated (n = 8), BRAF-mutated/PI3KCA wild-type (n = 16) and BRAF wild-type/PI3KCA-mutated (n = 20) tumours, respectively (P = 0.0002). PFS was similar with bevacizumab plus FOLFIRI versus cetuximab plus FOLFIRI in BRAF/PIK3CA wild-type (HR = 0.99; 95% CI 0.67-1.45; P = 0.9486) and BRAF/PIK3CA-mutated tumours (HR = 1.11; 95% CI 0.53-2.35; P = 0.7820). The most common grade 3/4 treatment-related adverse events were neutropenia, diarrhoea and asthenia in both treatment groups.

Conclusions

BRAF/PIK3CA status influences outcomes in patients with RAS wild-type mCRC but does not appear to assist with the selection of first-line targeted therapy.

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This study examined if BRAF/PIK3CA mutational status can guide therapy in RAS wild-type mCRC.

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BRAF mutations were associated with poorer survival outcomes, and were potentiated by PI3KCA mutations.

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Bevacizumab-FOLFIRI versus cetuximab-FOLFIRI had similar outcomes in BRAF /PIK3CA wild-type and BRAF /PIK3CA-mutated tumours.

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BRAF and PI3KCA mutations have a role as prognostic but not predictive factors.

Temporal and spatial stratification for the estimation of nocturnal long-term noise levels

Noise pollution in cities is mainly caused by the vehicular traffic but, depending on the place under assessment, it could be affected by the land use. For noise assessment and strategic noise mapping, the night period equivalent level (L_night), which evaluates sleep disturbance, is one of the requirements of the European Directive 2002/49/EC to be presented for the equivalent time of one year. This research aims to find the influence of the land use in the weekdays stratification to improve the accuracy of the long-term noise level estimation for the night period. It is found that depending on the land use of the place under assessment, the weekdays temporal and spatial stratification could be affected by leisure activities. From a statistical analysis based on a clustering procedure of L_night samples in 19 points, it is observed that both, temporal and spatial stratification depend on the intensity of the surrounding leisure activity, and not on traffic. Following these stratification criteria, a sampling method is presented that reduces by 47% the number of days needed to estimate the annual levels with respect to random sampling.

Annual traffic noise levels estimation based on temporal stratification

This paper proposes a temporal sampling strategy that increases the accuracy of long-term noise level estimation and allows to establish the estimation error according to the number of sampled days. Days of the week are stratified into working days and weekend days. This research shows how to use measurements of L_eq on working days to estimate the corresponding values for weekend days. This is possible because working days have higher noise levels and less variability than weekend days. The improvement in accuracy allows for a reduction in the number of required sampled days compared to taking samples randomly, which would help to reduce the uncertainty in environmental noise assessment. As a reference, to obtain a 90% confidence interval of ±1 dB for L_day, the proposed sampling strategy reduces the required measurement days by more than 38%. For L_DEN, the reduction is close to 18% of the total number of days. The proposed strategy could be adapted to different environments by simply changing a few parameters.

A retrospective observational study on the safety and efficacy of first-line treatment with bevacizumab combined with FOLFIRI in metastatic colorectal cancer

BACKGROUND

Combination of bevacizumab and FOLFIRI has currently become one of the standard therapeutic regimens. However, published information is still limited. The objective of the present retrospective observational study is to analyse the response and toxicity of first-line treatment with FOLFIRI+bevacizumab in patients with metastatic colorectal cancer (mCRC).

METHODS

Data were collected from patients from nine Spanish sites diagnosed with mCRC, ECOG≤2, whose first treatment for advanced disease was at least three cycles of FOLFIRI+bevacizumab.

RESULTS

A total of 95 patients were enrolled into the study: 64.2% males, median age of 59 years (53.2-67.1 years), ECOG=0-1 in 96.9% of patients. The main site of primary tumour was the colon (69.7%), and most metastases occurred in the liver (71.6%). Clinical benefit was detected in 67.4% (57.0-76.6; 95% confidence interval (CI)), with 8.4% of CR and 42.1% of PR. Median TTP was 10.6 months (10.0-11.3; 95% CI), PFS was 10.6 months (9.8-11.3; 95% CI), and OS was 20.7 months (17.1-24.2; 95% CI). Main grade I-II toxicities included haematological toxicity (35.8%), diarrhea (27.3%), mucositis (25.3%), asthenia (19.0%), haemorrhages (11.6%), and emesis (10.6%). Toxicities reaching grades III-IV were haematological toxicity (9.5%), diarrhea (8.5%), mucositis (5.3%), hepatic toxicity (2.1%), asthenia (2.1%), proteinuria (1.1%), emesis (1.1%), pain (1.1%), and colics (1.1%).

CONCLUSION

Results of this study support the beneficial effect of adding bevacizumab to FOLFIRI regimen in terms of efficacy and show a favourable tolerability profile.

Phase II study of biweekly XELOX (capecitabine and oxaliplatin) as first line chemotherapy in elderly patients with metastatic colorectal cancer

e15053

Background: Analysis of efficacy and toxicity of biweekly XELOX as first line monotherapy in elderly patients (pts) with metastatic colorectal cancer (MCRC), based in results of W. Scheithauer (J Clin Oncol 2003; 21: 1307). Methods: From March/06 to November/08, 28 chemonaïve elderly pts (>75 years old) with MCRC, PS: 0–2, and adequate renal, hepatic and bone marrow functions, were included in a phase II study of: oxaliplatin 85 mg/ m2/ day 1 plus capecitabine 2000/ m2/ in 2 divided doses/ days 1–7 every 2 weeks. Treatment was continued until 12 cycles, tumour progression or innaceptable toxicity. Response evaluation every 6 cycles and toxicity every cycle was performed. At present 28 pts for toxicity and 24 pts for response are evaluable. Results: Median age: 78.2 years (range: 73.5–79.5). Male/Female: 14/14. Rectal/Colon: 9/19. Metastatic sites 1/2/>2: 15/6/6. Liver 78.6%, Lung 32.1%, Local tumour 7.1%, Retroperitoneum 14.2%, Peritoneum 10.7%. and Bones 7.1 %. Previous adjuvant with 5-FU regimens to 4 pts. Comorbidity grade by Charlson index 0–1/2/>2: 60.8%/ 28.6% / 10.7%, respectively. Median number of cycles for oxaliplatin and capecitabine were 8 (5.25–12) and 8 (5.25–11.75). Response rate: 2 pts complete response (8.3%), 8 pts partial response (33.3%),10 pts stable disease (41.7 %) and 4 pts progression (16.7%). The main CTC toxicity was Asthenia G2+3 in 6 (21.5%), Nausea and emesis G2 in 7 (25%), Diarrhea G2+3 in 7 (25%) and Hand-foot syndrome G1+2 in 5 pts (17.8%). No G4 toxicity or toxic deaths were observed. Median time to progression was 8.6 months.Median overall survival will be given updated at the congress. Conclusions: Preliminary results suggest that bi-weekly XELOX is an effective first line treatment for MCRC in elderly pts with an acceptable toxicity profile (especial surveillance of diarrhea is necessary) and protocol cumpliment. Combination with bevacizumab should be considered.

No significant financial relationships to disclose.

Multicenter phase II study of cetuximab and irinotecan as third line chemotherapy in patients (pts) with metastatic colorectal cancer (MCRC) previously treated with both irinotecan and oxaliplatin regimens

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Background: Pts with chemotherapy-resistant MCRC have a really poor prognosis with few therapeutic options. Cetuximab (Erbitux®) is an IgG1 monoclonal antibody targeting the EGFR, shown to be effective in pts with EGFR-expressing MCRC refractory to prior irinotecan-based chemotherapy (Cunningham NEJM 2004). Methods: The goal of this multicenter phase II study is to investigate the safety and efficacy of cetuximab in combination with irinotecan as third line treatment in 40 pts with heavily pre-treated MCRC. From Jan to Dec 2005, 40 pts with EGFR-expressing MCRC, refractory to irinotecan, pre-treated with both irinotecan and oxaliplatin with fluorouracil or capecitabine combinations, and PS 0–2, were included to receive cetuximab (400 mg/m2 week 1 and 250 mg/m2 weekly thereafter) plus irinotecan (180 mg/m2 every 2 weeks) until tumour progression or unacceptable toxicity. Pts were analysed weekly for toxicity and every 12 weeks for response. Recruitment is completed. Currently, 38 pts are evaluable for toxicity (2 pts recently recruited) and 23 pts for response (16 pts on treatment for <12 weeks and 1 pt withdrew at week 6 due to lung thromboembolism not related to study treatment). Results: M/F 24/14, median age 63 years (range: 33–78), colon/rectum 23/15, ECOG PS=0/1/2 9/23/6, Metastatic sites 1/2/>2 16/19/3 (Liver 43%, lung 23%, nodes 17%, pelvic 5%, others 12%). A total of 418 weekly infusions were administered (mean: 11; range: 3–37). Preliminary efficacy data is as follows: 3 PR, 3 SD, 17 PD with an overall response rate of 13% (95% CI: 3–34%) and disease control rate of 26% (95% CI: 10–48%). Major toxicities (G 1–2/G 3–4) were: Acne-like skin rash 58/11%, Anemia 32/3%, Neutropenia 16/13%, Nausea-vomiting 32/0%, Diarrhoea 32/11%. Median time to progression was 3.5 months (Range: 1–10+) and median overall survival was 7.3 months (Range: 1.5–12+). Conclusions: These preliminary results suggest that cetuximab and irinotecan combination, is a reasonably effective treatment for pts with highly pre-treated MCRC with an acceptable toxicity profile

No significant financial relationships to disclose.

Albumin-derived advanced glycation end-products trigger the disruption of the vascular endothelial cadherin complex in cultured human and murine endothelial cells

Endothelial cell (EC) junctions regulate in large part the integrity and barrier function of the vascular endothelium. Advanced glycation end-products (AGEs), the irreversibly formed reactive derivatives of non-enzymic glucose-protein condensation reactions, are strongly implicated in endothelial dysfunction that distinguishes diabetes- and aging-associated vascular complications. The aim of the present study was to determine whether AGEs affect EC lateral junction proteins, with particular regard to the vascular endothelial cadherin (VE-cadherin) complex. Our results indicate that AGE-modified BSA (AGE-BSA), a prototype of advanced glycated proteins, disrupts the VE-cadherin complex when administered to ECs. AGE-BSA, but not unmodified BSA, was found to induce decreases in the levels of VE-cadherin, beta-catenin and gamma-catenin in the complex and in total cell extracts, as well as a marked reduction in the amount of VE-cadherin present at the cell surface. In contrast, the level of platelet endothelial cell adhesion molecule-1 (PECAM-1), which is located at lateral junctions, was not altered. Supplementation of the cellular antioxidative defences abolished these effects. Finally, the loss of components of the VE-cadherin complex was correlated with increases in vascular permeability and in EC migration. These findings suggest that some of the AGE-induced biological effects on the endothelium could be mediated, at least in part, by the weakening of intercellular contacts caused by decreases in the amount of VE-cadherin present.

Analgesic and anti-inflammatory effects of Mangifera indica L. extract (Vimang)

Vimang is an aqueous extract of Mangifera indica used in Cuba to improve the quality of life in patients suffering from elevated stress. To assess its possible analgesic and antiinflammatory effects, the results of a standard extract evaluation are presented. Analgesia was determined using acetic acid-induced abdominal constriction and formalin-induced licking. Antiinflammatory effects were evaluated using carrageenan- and formalin-induced oedema. Vimang (50-1000 mg/kg, p.o.) exhibited a potent and dose-dependent antinociceptive effect against acetic acid test in mice. The mean potency (DE(50)) was 54.5 mg/kg and the maximal inhibition attained was 94.4%. Vimang (20-1000 mg/kg, p.o.) dose-dependently inhibited the second phase of formalin-induced pain but not the first phase. The DE(50) of the second phase was 8.4 mg/kg and the maximal inhibition was 99.5%, being more potent than indomethacin at doses of 20 mg/kg. Vimang (20-1000 mg/kg, p.o.) significantly inhibited oedema formation (p < 0.01 or p < 0.05) of both carrageenan- and formalin-induced oedema in rat, guinea-pigs and mice (maximal inhibitions: 39.5, 45.0 and 48.6, respectively). The inhibitions were similar to those produced by indomethacin and sodium naproxen, p.o. The different polyphenols found in Vimang could account for the antinociceptive and antiinflammatory actions reported here for the first time for M. indica bark aqueous extract.

"The lizard in the green bottle": "aging out" of problem drinking among Navajo men

The Navajo exhibit a number of indicators suggesting the extent of significant problems associated with drinking and alcohol abuse. Measures of alcohol-related mortality and morbidity provide stark testimony regarding the shape and magnitude of problem drinking among the Navajo. While these measures highlight patterns of drinking that often result in social, physical, and psychological pathology, there are other, less noted patterns of Navajo drinking. This paper describes a salient, if often overlooked, pattern of Native American drinking by examining the aging out phenomenon among Navajo men. Using narratives collected from former problem drinkers, this paper describes the factors and motivations associated with this sometimes dramatic change in drinking behavior. Several themes emerge from these narratives that help explain the aging out process. These themes include health concerns, religious involvement, living a traditional Navajo way of life, and the responsibilities and life changes associated with child rearing. This paper not only provides detail on a category of drinker and drinking phenomena that is largely ignored in accounts of Native American drinking, but also illustrates some of the values and meanings attached to drinking cessation and highlights the relation between changes in drinking behavior and stages in life course among Navajo men.

Risk factors for conduct disorder among Navajo Indian men and women

OBJECTIVES

To describe the risk factors for conduct disorder before age 15 among Navajo Indians.

METHODS

The study was based on a survey of a stratified random sample of adult Navajo Indians between the ages of 21 and 65 living on and adjacent to two different areas of the Navajo Reservation. There were 531 male and 203 female respondents. The average age (SD) of the men was 38.7 (10.5) years and of the women 35.5 (9.0) years. Conduct disorder was diagnosed retrospectively using the Diagnostic Interview Schedule first developed for the Epidemiological Catchment Area study. The responses were combined into a continuous scale.

RESULTS

Significant risk factors for increased scores on the conduct disorder scale were: histories of physical and sexual abuse in childhood; abusive maternal drinking; a small number of households per camp; younger age; and being male rather than female. Measures of social status and religion in which subjects were raised were not significant.

CONCLUSIONS

Many of the risk factors that are associated with conduct disorder in other populations are also risk factors in the Navajo population. There is suggestive evidence that some of these risk factors have become more common since World War II, raising the possibility that conduct disorder has become more prevalent, as is thought to be the case nationwide.

Alcohol dependence and conduct disorder among Navajo Indians

OBJECTIVE

The purpose of this study is to examine the association between conduct disorder before age 15 and subsequent alcohol dependence, and to describe the lifetime prevalence of alcohol dependence among Navajo Indian women and men.

METHOD

This was a case-control design which included both men (n = 735) and women (n = 351) and in which the Diagnostic Interview Schedule was used for the diagnosis of the lifetime history of alcohol dependence and conduct disorder. Alcohol dependent cases were selected from inpatient and outpatient treatment programs (204 men, 148 women). Whenever possible, controls were matched for age, sex and community of residence and were randomly selected and interviewed until a nonalcohol dependent individual was found. Among the men, there were 374 alcohol dependent controls and 157 nonalcohol dependent controls. Among the women, the figures were 60 and 143, respectively. When combined, the controls comprise samples of the adult male and female populations from which estimates of lifetime prevalence of alcohol dependence, and of the amount of alcohol dependence in the population attributable to conduct disorder, may be inferred.

RESULTS

Conduct disorder is a risk factor for alcohol dependence among both men and women. Lifetime prevalence of alcohol dependence in this population is high (70.4% for men and 29.6% for women), but the amount of alcohol dependence in the population attributable to conduct disorder is low. On the other hand, among the alcohol dependent, those with conduct disorder had the most severe alcohol- and nonalcohol-related problems.

CONCLUSIONS

The potential limitations of the study are those common to case-control designs, especially biased recall by cases. There are also potential sampling biases among the controls. It is shown that none of the potential biases invalidate the findings, which support the hypothesis that in this population conduct disorder is a risk for alcohol dependence. The implications for primary prevention of alcohol dependence are discussed.

Immunogenicity of four Plasmodium falciparum preerythrocytic antigens in Aotus lemurinus monkeys

Aotus lemurinus monkeys were immunized with pools of either lipid-tailed peptides injected in PBS or peptides in Montanide ISA-51, all derived from four Plasmodium falciparum pre-erythrocytic antigens, namely, LSA1, LSA3, SALSA, and STARP. These formulations were well tolerated. Their immunogenicity was demonstrated by the induction of both B- and T-cell responses to most of the peptides studied (of the 12, 10 induced antibody production, 9 induced T-cell proliferative responses, and all 12 induced gamma interferon secretion). Immune responses proved to be long lasting, since some were still detectable 210 days after immunization. Of particular importance is the fact that B- and T-cell responses elicited in this way by synthetic peptides were specific for native parasite proteins on P. falciparum sporozoites and liver stage parasites.

Smoking experimentation and initiation among adolescent girls: qualitative and quantitative findings

OBJECTIVE

To use qualitative and quantitative findings to describe patterns of smoking experimentation and initiation among adolescent girls.

DESIGN

Ethnographic in-person interviews, focus groups, telephone interviews, and a survey questionnaire were used over a one-year period. The paper reports on cross-sectional data drawn from a three-year longitudinal study.

SUBJECTS AND SETTING

205 girls participated in the survey and interviews during year 3 of the study. Girls were drawn from two urban high schools in Tucson, Arizona (USA), and were in grades 10 and 11 (mean ages 16 and 17, respectively) during year 3.

RESULTS

Overall, 30% (n = 61) of informants reported that they currently smoked, 7% (n = 15) were ex-smokers, and 63% (n = 129) were "non-smokers". The most frequently cited reasons for smoking were stress reduction and relaxation. Several stress-inducing situations, including family environment, social relations with classmates, and schoolwork, are discussed. The notion of peer pressure is re-examined in the light of teenagers' experience that there is little overt pressure to initiate smoking. Consonant with notions of adolescent autonomy, the theme of independence in smoking initiation and continuation permeated girls' narratives about their smoking behaviour. Girls projected the image that they could control their cigarettes rather than have their cigarettes control them.

CONCLUSIONS

Smoking prevention and cessation programmes need to address and counter the smoking/relaxation association, which was identified as an important reason for smoking among adolescent girls. Questions typically used in surveys to measure smoking behaviour do not adequately define the smoking experience as described by teenagers.

Treatment of 3rd molar-induced periodontal defects with guided tissue regeneration

Recent reports provide evidence of increased attachment levels when using guided tissue regeneration (GTR) techniques for the treatment of periodontal defects. Periodontal defects frequently occur at the distal aspect of mandibular 2nd molars which are next to mesioangular impacted 3rd molars that have oral communication. The purpose of this study was to determine whether the use of GTR can enhance probing attachment levels (PALs) following extraction of mesioangular impacted third molars. 12 patients with bilateral soft tissue impacted mandibular 3rd molars entered this split mouth study. After extractions, the previously exposed distal root surface of the 2nd molars were debrided. The defects on the randomly selected experimental sites were covered with expanded polytetraflouro-ethylene (e-PTFE) membrane and the tissue was replaced to cover the membrane. Membranes were removed after 6 weeks. Control sites were treated identically except no membrane was placed. GI, P1I, PD, PAL and BOP records were obtained at 0, 3 and 6 months. The use of barrier material did not provide statistically-significant differences in PAL when comparing experimental versus control sites. Nevertheless, PAL gain was consistently greater at 3 and 6 months when GTR techniques were used in sites with deep impactions.

The semantics of addiction: moving beyond expert models to lay understandings

Five expert discourses on addiction purport to explain the phenomenon of the semantics of addiction. An assessment of the burgeoning use of this term by the lay public, however, reveals a plethora of socially contextualized and culturally mediated meanings related to addiction that are generally not considered by expert models. Addiction has meanings that index the loss of self-control and individual responsibility, as well political and moral meanings and meanings that index social modes of consumption, the range and limits of normative behavior, and the constitution of deviance. The category of addition interacts with other socially produced categories, including "drugs" and "desires," and implies an unfolding history linked to specific cultural conventions of what is proper. This paper briefly reviews expert debates over the meanings of addiction and explores the semantics of how this term is used in both popular discourse and among those who use substances associated with physical addiction. In addition, some of the more interesting theoretical issues this discussion brings to light are highlighted, with the intent to identify issues warranting future research that will broaden the study of addiction.

Bone grafting and guided bone regeneration for immediate dental implants in humans

This study evaluated bone regeneration and osseointegration of hydroxyapatite (HA) coated and titanium plasma sprayed (TPS) implants placed in sockets immediately after extraction in 36 adults, mean age 55.2 years (range 26 to 81 years). Twelve TPS and 10 HA-coated implants in 20 patients were grafted with demineralized freeze-dried bone allograft (DFDBA), covered with a barrier material, and the facial flap coronally positioned to attain primary closure (experimental). The remaining 11 TPS and 10 HA-coated implants were placed similarly, except that no DFDBA was used (control). Osseous structures were measured at the initial placement and 6-month re-entry surgeries. At the 6-month re-entry, all implants placed were clinically osseointegrated. Bone resorption at the most coronal socket crest was -1.53 mm for the grafted group and -1.59 mm for the control group. Crestal bone apposition of 1.39 mm was noted at the most apical socket crest (ASC) for the grafted group, whereas crestal resorption of -0.11 mm was noted in the ungrafted control group (P < 0.02). Bone fill from the base of the deepest osseous defect was 5.68 mm for the grafted group and 3.18 mm for the control group (P < 0.04). Complete resolution of osseous defects occurred at 15 of 22 sites in the grafted group and at 9 of 21 sites in the control group. Clinical exposure of the barrier material and a subsequent inflammatory response at 27 of 43 sites, requires removal of the material prior to the 6-month re-entry and was associated with significantly more bone loss at the ASC sites (P < 0.01). There was no significant difference for any of the parameters when comparing the TPS with the HA-coated implants.

Combined dental implant and guided tissue regeneration therapy in humans

This study evaluated wound healing and osseointegration of dental implants placed in immediate postextraction sockets in humans. Ten healthy adults had one or more teeth extracted and replaced with ITI dental implants, which were centered in the residual socket and covered with a polytetrafluoroethylene membrane and a flap to attain primary closure. Measurements were made to document the relationship of bone to implant at the time of implant placement and at the 6-month reentry. All implants were clinically osseointegrated at the 6-month reentry procedure; narrow bony defects showed complete bone fill, while wide defects showed partial bone fill. There was less bone regeneration in areas of thin cortical bone or preexisting dehiscences and in implant sites with early membrane exposure. Implants placed in immediate postextraction sockets demonstrated successful osseointegration with irregular bone-healing patterns, which were related to variations in existing bony anatomy and socket location.

Interpretation of linear and computed tomograms in the assessment of implant recipient sites

Tomography is a radiographic process that produces cross-sectional images of bony structures within the body. The purpose of this study was to evaluate the accuracy of diagnostic measurements made by dental implant team members from linear tomograms of human cadaver mandibles. Five partially edentulous cadaver mandibles were radiographed using linear tomography (LT) and computer-assisted tomography (CT). From the tomograms, each of four team members traced the perceived outer circumference of the mandible and the inferior alveolar canal. Tomogram tracings were compared to each other and to the equivalent CT cross-sectional image to determine the precision of the measurements. One mandible was sectioned to verify the accuracy of the CT images. Repeated measures analysis of variance of the measurements made from the LT and CT scans showed significant statistical differences between team members. Multiple cross-sectional views facilitated identification of the inferior alveolar canal in the majority of CT scans, whereas image blurring inherent to LT resulted in the inability of team members to identify the canal in 14% to 50% of the images. Volume averaging within the CT slice aperture was found capable of producing a magnification error of short dense objects. CT and LT must both be interpreted cautiously because of innate technique objects. CT and LT must both be interpreted cautiously because of innate technique pecularities that can lead to measurement errors. The wide variation in interpretation of the linear tomograms and frequent inability to identify the inferior alveolar canal made this technique less valuable than the reformatted CT when planning dental surgical procedures.

Small versus large particles of demineralized freeze-dried bone allografts in human intrabony periodontal defects

Various particle sizes of demineralized freeze-dried bone allograft (DFDBA) are currently used to treat patients with periodontal osseous defects. However, the effect of particle size on the healing of human intrabony periodontal defects is unknown since there have been no direct clinical comparisons. The purpose of this study was to compare the bony defect resolution obtained using two different particle size ranges of DFDBA. Cortical bone from a single donor was processed and ground to final particle sizes of 250 mu to 500 mu or 850 mu to 1,000 mu using an analytic mill. Paired interproximal intrabony periodontal defects in 11 patients were grafted with DFDBA. Soft and hard tissue measurements were made using an electronic constant-force probe at the initial and reentry surgeries. Treated sites in 10 patients were reevaluated by reentry approximately 6 months postoperatively. Mean bony defect fill was 1.66 mm for the large particle group and 1.32 mm for the small particle group. There was no statistically significant difference in bony fill between defects grafted with the different particle sizes of DFDBA when used in humans.

Displacement chromatography on cyclodextrin silicas. IV. Separation of the enantiomers of ibuprofen

A displacement chromatographic method has been developed for the preparative separation of the enantiomers of ibuprofen using a beta-cyclodextrin silica stationary phase. The retention behavior of ibuprofen was studied in detail: the log k' vs. polar organic modifier concentration, the log k' vs. pH, the log k' vs. buffer concentration and the log k' vs. 1/T relationships; also, the alpha vs. polar organic modifier concentration, the alpha vs. pH, the alpha vs. buffer concentration and the log alpha vs. 1/T relationships have been determined in order to find the carrier solution composition which results in maximum chiral selectivity and sufficient, but not excessive solute retention (1 < k' < 30). 4-tert.-Butylcyclohexanol, a structurally similar but more retained compound than ibuprofen, was selected as displacer for the separation. Even with an alpha value as small as 1.08, good preparative chiral separations were observed both in the displacement mode and in the overloaded elution mode, up to a sample load of 0.5 mg.

A comparison of polylactic acid granules and decalcified freeze-dried bone allograft in human periodontal osseous defects

The purpose of this study was to compare the effectiveness of polylactic acid (PLA) granules as an alloplastic grafting material to that of decalcified freeze-dried bone allograft (DFDBA) and a flap procedure for debridement without graft (FPD) when treating periodontal intrabony defects. Ten patients presenting with advanced adult periodontitis, including at least 3 similar periodontal osseous defects (2- and 3-walled), comprised the study group. After completion of a hygienic phase of treatment, measurements were made with calibrated periodontal probes and stents to determine soft tissue recession, probing pocket depths, and probing attachment levels. Each defect was surgically exposed and hard tissue measurements were obtained. Defects were treated with one of the 3 methods above chosen randomly prior to the surgical appointment. Six months postsurgery, soft tissue measurements were repeated and all sites were surgically reentered to obtain hard tissue measurements. All surgical sites healed without clinical complication. The initial pocket depths and initial depth of osseous defects were compared between the groups using ANOVA and no significant differences were found. A mean osseous defect fill of 0.4 mm (11.2%) occurred with the flap procedure for debridement, 3.0 mm (65%) with DFDBA, and 0.1 mm (2.2%) with PLA. Mean crestal bone loss was 1.30 mm for FPD, 0.60 mm for DFDBA, and 1.55 mm for PLA. No statistically significant differences were found in soft tissue recession between groups or in the osseous defect measurement between PLA and FPD. A statistically significant improvement (P < 0.001) was found in the fill of the osseous defects when using DFDBA compared to the initial defect depth and to the other 2 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Displacement chromatography on cyclodextrin-silicas. III. Enantiomer separations

The feasibility of preparative enantiomer separations by displacement chromatography on analytical-scale beta-cyclodextrin-silica columns, operated in the reversed-phase mode, was demonstrated using the enantiomers of mephobarbital, hexobarbital, dansylleucine, dansylvaline and dansylphenylalanine as model solutes. The method development scheme (which relies on the determination of the elution-mode retention behavior and the adsorption isotherms of the solutes and the candidate displacers) described in Parts I and II can be used to select the appropriate displacers and the conditions leading to a successful displacement chromatographic separation. The importance of the displacer (both type and concentration) to the success of the displacement chromatographic separation is demonstrated.

Displacement chromatography on cyclodextrin-silicas. I. Separation of positional and geometrical isomers in the reversed-phase mode

The retention behaviour of several charged and uncharged solutes on beta-cyclodextrin-silica was studied as a function of the methanol concentration, ionic strength and pH of the eluent in order to develop efficient displacement chromatographic separations for positional and geometric isomers. These retention curves were used to predict the eluent (carrier solvent) compositions that result in solute retentions in excess of k' = 10. The adsorption isotherms of several cationic detergents were determined in these carrier solutions and were found to be convex. The adsorption isotherms of several positional isomers used as test solutes were also determined in these carrier solutions. The adsorption isotherms permitted the development of efficient displacement chromatographic separations for the isomers tested. Column loadings as high as 58 mg were achieved on a regular 4.6 mm I.D. analytical-scale cyclodextrin silica columns.

Displacement chromatography on cyclodextrin-silicas. II. Separation of cis-trans isomers in the reversed-phase mode on alpha-cyclodextrin-silica

The feasibility of preparative separations of cis-trans isomers by displacement chromatography on analytical-scale alpha-cyclodextrin-silica columns operated in the reversed-phase mode is demonstrated by using the isomers of 3-hexen-1-ol as model substrates and n-alkanols as displacers. The importance of matching the size of the cyclodextrin cavity and the solutes is shown. The crucial role of the displacer (both type and concentration) in the success of the displacement chromatographic separation is demonstrated.

A six-month clinical evaluation of decalcified freeze-dried bone allografts in periodontal osseous defects

The osteogenic potential of decalcified freeze-dried bone allografts in the treatment of human periodontal osseous defects was evaluated over a 6 month period. Cortical bone, obtained under sterile conditions from a human donor within 24 hours after death, was decalcified, freeze-dried and ground to a particle size of 250 to 500 microns. Twenty-seven osseous defects with one-, two- and wide three-wall morphology were treated. Clinical measurements were made with a stent and a calibrated periodontal probe before surgery, at the time of surgery, and at re-entry. The combined mean osseous regeneration for all defects was 2.4 mm. This represented a 65% mean bone-fill of the original defect. The findings demonstrate that decalcified freeze-dried bone allograft has potential as an osseous grafting material in periodontal therapy.

Comparative analysis of some anthropometric measurements

The main objective of this work is to determine what anthropometric method to use under field conditions, given the kind of mainutrition to be detected. In the first part of the work some criteria and procedures are given by which to compare the field perfomance characteristics (i.e. transportability, facility of use, etc.), of the most commonly used instruments. Then we extrapolate these characteristics to the respective methods like weight for age, weight for height, height for age, etc. In the second part we present a correlation matrix among the various methods and analyze it in order to associate with each method a specific typology of malnutrition.

Screening for malnutrition with arm circumference

The opinions on the performance characteristics of the mid arm circumference as anthropometric measurement for malnutrition screening are quite contradictory. In this paper we analyze the specificity and sensitivity of the arm tape under different conditions and conclude that the design of the tape characteristics should aim at an instrument which can satisfy specific needs instead of a general purpose one. We also give some measurements for the practical design of the instrument. 1. This investigation has been carried out under the Contract AID/ta-C-1121 and the Fundación para la Educación Superior. 2. Universidad del Valle. 3. Fundación para la Educación Superior. 4. Community Systems Foundation.

The affinity of low density lipoproteins for an arterial macromolecular complex. A study in ischemic heart disease and controls

Levels of serum cholesterol, triglycerides, lipoprotein pattern and the insolubilization of serum low density lipoproteins (LDL, betalipoprotein) by a factor present in arterial intima--media extracts was investigated in 55 patients with acute coronary heart disease and 50 healthy controls. In blood samples obtained 24 h after the episode, the serum betalipoproteins from male normotensive patients showed a high tendency to precipitate when incubated with the intima-media extracts, nearly twice the value measured in the control group. This affinity returned almost to control level after 21 days in the hospital. Hypertensive patients showed a serum cholesterol higher than the controls but almost no difference in LDL-arterial factor interaction. The composition of isolated LDL was studied in 7 patients and 8 controls and it was found that the total cholesterol/protein plus phospholipid ratio has a positive exponential correlation with the lipoprotein-arterial factor affinity. The results of LDL analyses suggest that a change in their composition, frequent in normotensive patients, can lead to an increased affinity of this lipoprotein for arterial intimamedia components. It is proposed that this process could be an additional risk factor contributing to the deposition of LDL in the arterial wall.