Pattern of Opioid Analgesic Prescription for Adults by Dentists in Nova Scotia, Canada

Global consumption of prescription opioid analgesics has increased dramatically in the past 2 decades, outpacing that of illicit drugs in some countries. The increase has been partly ascribed to the widespread availability of prescription opioid analgesics and their subsequent nonmedical use, which may have contributed to the epidemic of opioid abuse, addiction, and overdose-related deaths. International studies report that dentists may be among the leading prescribers of opioid analgesics, thus adding to the societal impact of this epidemic. Between 2009 and 2011, dentists in the United States prescribed 8% to 12% of opioid analgesics dispensed. There is little information on the pattern of opioid analgesic prescription by dentists in Canada. The aim of this study was to examine the pattern of opioid analgesics prescription by dentists in Nova Scotia (NS), Canada. This retrospective observational study used the provincial prescription monitoring program's record of oral opioid analgesics and combinations dispensed to persons 16 y and older at community pharmacies that were prescribed by dentists from January 2011 to December 2015. During the study period, more than 70% of licensed dentists in NS wrote a prescription for dispensed opioid analgesics, comprising about 17% of all opioid analgesic prescribers. However, dentists were responsible for less than 4% of all prescriptions for dispensed opioid analgesics, prescribing less than 0.5% of the total morphine milligram equivalent (MMEq) of opioid analgesics dispensed over the 5 y. There was a significant downward trend in total MMEq of dispensed opioid analgesics prescribed by dentists from about 2.23 million MMEq in 2011 to 1.93 million MMEq in 2015 (r = -0.97; P = 0.006). Opioid prescription is common among dentists, but their contribution to the overall availability of opioid analgesics is low. Furthermore, there has been a downward trend in total dispensed MMEq of opioid analgesics prescribed by dentists. Knowledge Transfer Statement: This study will serve to inform dentists and policy makers on the types and dosage of opioid analgesics being prescribed by dentists. The study may prompt dentists to reflect on and adjust their practice of opioid analgesic prescription in view of the current opioid analgesic epidemic.

Bleeding emergencies in neonatal and paediatric patients: improving the quality of care using simulation

OBJECTIVES

Using a multidisciplinary approach and simulation, a massive transfusion process (MTP) was developed to care for patients in need of emergency transfusion. It was then assessed for effectiveness.

BACKGROUND

After a series of sentinel emergency bleeding events, a reliable process for hospital staff to deliver appropriate blood products and obtain relevant laboratory tests to guide therapy for patients with emergency bleeding was needed.

METHODS

To determine the feasibility of the new MTP, multidisciplinary teams participated in simulation events. Each simulation event helped refine the MTP. A special laboratory testing panel was devised. To judge the effectiveness and timeliness of the MTP, process measures and patient survival was retrospectively evaluated during the time period before and after MTP implementation.

RESULTS

A new emergency bleeding panel of laboratory tests significantly decreased the turn-around time for fibrinogen, haematocrit, International normalised ratio (INR) and platelet count. The speed of commencing the first red blood cells transfusion was also improved (2:00 h vs 0:20 min, P = 0·001). Of 78 patients, there was no change in survival before (n = 31, 48·4%) and after (n = 47, 42·6%; P = 0·6478) MTP implementation. However, there was significant improvement in survival associated with MTP events on the weekdays.

CONCLUSIONS

A reliable emergency transfusion process consists of an automatic chain of events that keeps decision-making to a minimum and leads to the fast procurement of blood products and salient test results. This work shows that a multidisciplinary iterative process using simulation increases the efficiency of clinical care delivery for bleeding paediatric and neonatal patients.

Factors Influencing Adoption of New Technologies into Dental Practice: A Qualitative Study

The objective of this study was to explore factors affecting decisions to adopt new technologies into dental practice using a colorimetric rinse test for detection of periodontal disease as a model. Focus groups with key informants in Canadian dentistry and dental hygiene were conducted. A deductive approach used Rogers's diffusion of innovation theory as a framework for organizing codes and subcodes. Two members of the research team independently reviewed and analyzed the data using NVivo 10. The attributes of the technology itself emerged as primary influencers. Perceived relative advantages of the diagnostic mouth rinse over existing methods were potential time efficiency, low implementation cost, and utility of the tool. Low complexity, compatibility with existing routines/beliefs, and the potential for reinvention-the use of a technology for other than its intended purpose (i.e., patient education, monitoring of disease, screening tool in nondental settings)-were other important features enhancing adoption. An overarching concern was that any new technology benefit the patient. Contextual factors also play a role. Numerous communication channels, including opinion leaders, patients, marketing, continuing education courses, and strength of evidence, influenced clinicians, with peer interaction being a stronger influence than marketing. Similar themes arose from specialist, general dentist, and dental hygienist focus groups. Adopter characteristics also came into play: participants ranged in their self-reported innovativeness with many considering themselves "early adopters" of new technology. Findings of this study suggest that the innovation adoption process is not straightforward, but attributes of the innovation, contextual factors, and adopter characteristics play important roles in the process. Knowledge Transfer Statement: Various factors affect the adoption of new tools into clinical dental practice. These include attributes of the test or tool itself, the context of the settings in which the tool is introduced to practitioners, and the characteristics of the clinicians themselves. A qualitative study of dentists and dental hygienists investigated these factors. Situations in which dentists and hygienists interact with their peers and colleagues-through social networks, continuing education courses, conventions, or personal contact-were a major driver in the decision to adopt new technologies. However, even among "early adopters," most were reluctant to use new tests or tools unless they perceived a benefit to their patients or practice.

Using interviews to construct and disseminate knowledge of oral health policy

OBJECTIVES

Policymakers worldwide are challenged by the problem of oral health inequities. The goal of an interprovincial partnership in Canada was to guide policy aimed at improving the oral health of vulnerable populations. Insights regarding barriers and enablers to developing such policy in one province (Newfoundland & Labrador, Canada) were required to enhance collaboration between decision makers and researchers and to contribute to the evidence informing policy development.

METHODS

Snowball technique identified fourteen key informants. Semistructured audio-recorded interviews were conducted in person or by telephone. Two researchers independently conducted the analyses of the transcribed interviews, one using NVivo software and the second, manual coding. Triangulation of the analyses confirmed the findings.

RESULTS

Agreement between the two approaches showed that most key informants believed that oral health is an important policy issue; however, most felt it was not a high priority among the general public and most were unable to articulate the policy process. Barriers to oral health becoming a governmental priority were related to resource allocation and to poor communication among some groups including dentists and dental hygienists. Current government programmes and initiatives were praised but considered weak in health promotion strategies. Recommendations for enhancing oral health priority varied.

CONCLUSIONS

Attention to the methodological considerations of qualitative research enhanced the credibility of the method and confidence in the findings. Leveraging of existing programmes and improving communication were recommended to contribute to raising the priority of oral health within the government, thereby increasing their commitment to address oral health care, particularly for vulnerable populations.

Post–Loop Electrosurgical Excision Procedure Sepsis in a Human Immunodeficiency Virus–Infected Woman

BACKGROUND

Squamous intraepithelial lesions are more prevalent in women infected with the human immunodeficiency virus (HIV) compared with immunocompetent women. Loop electrosurgical excision procedure (LEEP) is commonly used to treat squamous intraepithelial lesions because it may be performed as an outpatient procedure with minimal blood loss and a low complication rate.

CASE

We report a major infectious post-LEEP complication in an HIV-infected female who had an uneventful LEEP in which a cellulose hemostatic agent was used. Despite the severity of the infection, she was successfully treated with a minor surgical procedure along with broad antibiotic coverage.

CONCLUSION

Although a cellulose hemostatic agent contaminated with perineal secretions may have served as a nidus for infection, use of perioperative antibiotics or cervical cleansing should be considered to prevent sepsis in immunocompromised hosts.

Designing a framework of intelligent information processing for dentistry administration data

OBJECTIVES

This study was designed to test a cumulative view of current data in the clinical database at the Faculty of Dentistry, Dalhousie University. We planned to examine associations among demographic factors and treatments.

METHODS

Three tables were selected from the database of the faculty: patient, treatment and procedures. All fields and record numbers in each table were documented. Data was explored using SQL server and Visual Basic and then cleaned by removing incongruent fields. After transformation, a data warehouse was created. This was imported to SQL analysis services manager to create an OLAP (Online Analytic Process) cube.

RESULTS

The multidimensional model used for access to data was created using a star schema. Treatment count was the measurement variable. Five dimensions--date, postal code, gender, age group and treatment categories--were used to detect associations. Another data warehouse of 8 tables (international tooth code # 1-8) was created and imported to SAS enterprise miner to complete data mining. Association nodes were used for each table to find sequential associations and minimum criteria were set to 2% of cases. Findings of this study confirmed most assumptions of treatment planning procedures. There were some small unexpected patterns of clinical interest. Further developments are recommended to create predictive models.

CONCLUSIONS

Recent improvements in information technology offer numerous advantages for conversion of raw data from faculty databases to information and subsequently to knowledge. This knowledge can be used by decision makers, managers, and researchers to answer clinical questions, affect policy change and determine future research needs.

Outcome of allogeneic bone marrow transplantation for children with advanced acute myeloid leukemia

Allogeneic bone marrow transplantation (BMT) may offer the only chance of cure for children with acute myeloid leukemia (AML) in second complete remission (CR2) or with relapsed disease, but the outcome of these patients has not been clearly defined. We conducted a retrospective study of 58 children, median age 7.4 years (range 0.8-17.3), who received matched related or unrelated BMT at our institution for AML in CR2 (n = 12), in untreated first relapse (n = 11) or with refractory disease (n = 35), to identify risk factors associated with disease-free survival (DFS). Life threatening to fatal regimen-related toxicity was observed in 22% of patients. Estimates of DFS at 5 years (95% confidence interval) for patients in CR2, with untreated first relapse and refractory disease were 58% (27-80%), 36% (11-63%) and 9% (2-21%), respectively. Non-relapse mortality estimates were 0%, 27% (0-54%) and 17% (5-30%), and relapse estimates were 42% (14-70%), 36% (8-65%) and 74% (60-89%), respectively. Advanced disease phase and cytogenetic abnormalities at the time of transplantation were each associated with decreased DFS and increased relapse in multivariable regression models. Survival for children transplanted in CR2 or untreated first relapse is higher than that previously reported, but relapse remains the major cause of treatment failure regardless of disease stage.

Prevention of immunization to D+ red blood cells with red blood cell exchange and intravenous Rh immune globulin

BACKGROUND

Although young women who are D- occasionally receive unintentional transfusions with D+ red blood cells (RBCs), there are little data to assist with management of such an event. Two cases of D- girls transfused with D+ RBCs are reported. In an effort to prevent formation of anti-D, RBC exchange followed by administration of intravenous (IV) Rh immune globulin (RhIg) was used.

CASE REPORTS

Patient 1, a 56-kg, 16-year-old D- girl, was involved in a motor vehicle crash. She received 4 units of Group O uncrossmatched D+ RBCs. Thirty-six hours after admission, she underwent RBC exchange with 10 units of D- RBCs, followed by a total of 2718 microg of IV RhIg over 32 hours. Six months later, her antibody screen was negative. Patient 2, a 39-kg, 10-year-old D- girl with aplastic anemia, received 1 unit of D+ RBCs. She underwent RBC exchange on the same day with 5 units of D- RBCs, followed by a total of 900 microg of IV RhIg over 8 hours. Six months later her antibody screen was negative.

CONCLUSION

RBC exchange followed by a calculated dose of IV RhIg was successful in preventing allo-immunization to D. Several small studies suggest that both trauma and hematology patients may be less capable of becoming immunized with the transfusion of D+ blood components. Until these findings are more clearly defined, there will be times when prevention of immunization of any D- girl is desired. RBC exchange followed by RhIg appears to be one way to achieve this goal.

A placebo-controlled multi-centred evaluation of an anaesthetic gel (Oraqix) for periodontal therapy

AIMS

Six Canadian dental schools investigated the ability of a thermosetting gel containing 25 mg/g prilocaine and 25 mg/g lidocaine as active agents to produce analgesia in periodontal pockets utilizing a randomized, double-blind, placebo-controlled study.

MATERIALS AND METHODS

The study consisted of 130 patients, each of whom received the active or placebo gel in periodontal pockets in one quadrant of the mouth for 30 s prior to periodontal debridement (scaling and root planing). Pain was measured using both a 100-mm Visual Analogue Scale (VAS) and a Verbal Rating Scale (VRS).

RESULTS

The median VAS pain score for the patients treated with the anaesthetic gel was 5 mm (range 0-85 mm) as opposed to 13 mm (range 0-79 mm) in the placebo-treated patients (P=0.015). There was no significant difference in the percentage of patients reporting no or mild pain (78% and 76% for the anaesthetic gel and placebo, respectively). No significant differences were seen in patient demographics, or mandible versus maxilla.

CONCLUSIONS

The VAS pain scores showed that the anaesthetic gel 5% was statistically more effective than the placebo in reducing pain during periodontal debridement.

The use of radioimmunoconjugates in stem cell transplantation

Radiolabeled monoclonal antibodies have been used with encouraging results in conjunction with stem cell transplantation for patients with hematologic malignancies targeting a variety of surface antigens including CD33, CD45 and CD66 for leukemias, CD20 and CD22 for non-Hodgkin's lymphomas, and ferritin for Hodgkin's disease. The results obtained targeting epithelial antigens on solid tumors, however, have generally been less encouraging, primarily due to the relative insensitivity of these malignancies to ionizing radiation. In this report we review clinical studies that have incorporated myeloablative doses of targeted radiation using radiolabeled antibodies in conjunction with stem cell transplant regimens.

Willingness to pay for periodontal therapy: development and testing of an instrument

OBJECTIVES

The objective of this study was to develop and test the feasibility and validity of a willingness to pay (WTP) tool in a dental setting.

METHODS

A questionnaire measured individuals' preferences among alternative treatments for periodontal disease and the maximum they would be willing to pay for their treatment of choice in terms of dental insurance premiums. The questionnaire provides detailed information, in probabilistic terms, of the risks and benefits of treatment choices for moderate to advanced adult periodontitis. It was pilot tested on 23 periodontal patients and 18 dental school faculty and staff.

RESULTS

The majority (92.6%) felt the questionnaire was an accurate representation of treatments and outcomes, establishing face and content validity. In terms of construct validity, four hypotheses were tested: (1) manipulation of the outcomes of the preferred treatment led to a predictable shift in preferences for 38 subjects (92.7%); (2) although periodontal patients were not more likely to choose periodontal surgery than nonpatients (P = .14), those with a history of surgery were more likely to choose surgery again (P = .06); (3) WTP was positively related to income level (P = .05); and (4) subjects were willing to pay more for coverage for themselves than for others. Periodontal surgery was the preferred treatment for moderate to advanced periodontal disease, and was more strongly preferred than other choices (i.e., a higher WTP) for all income groups. The intraclass correlation coefficient for treatment preferences was 0.95 (P < .001) and the kappa for WTP was 0.78 (P < .001).

CONCLUSION

This pilot study supports some of the criteria concerning validity of the WTP questionnaire to measure preferences for alternative periodontal therapies. Further testing on larger samples is required to confirm these results.

Clinical practice guidelines in dentistry: Part II. By dentists, for dentists

There is a growing interest in clinical practice guidelines (CPGs) for all health care providers. As discussed in the first paper of this 2-part series, there are many misperceptions about guidelines and their potential risks and benefits. The dental profession in Canada, cognizant of both the importance and the challenges of developing sound, credible and relevant guidelines for dentists, has created a unique, autonomous collaboration of multiple stakeholders, the Canadian Collaboration on CPGs in Dentistry (CCCD). This paper discusses the history, structure and processes of the CCCD and introduces the first guideline under development by and for Canadian dentists.

Clinical practice guidelines in dentistry: Part I. Navigating new waters

Clinical Practice Guidelines (CPGs) are tools, developed by and for practitioners, to assist in clinical decision making. They are designed to enhance, not replace, clinical judgement and expertise. Well-developed guidelines use the evidence-based approach. The research evidence related to a topic is assembled in a systematic, comprehensive and unbiased manner. Recommendations are made based on the evidence and practitioner feedback is sought prior to formulating the final practice guideline. There are many misperceptions about CPGs and some dentists are wary about their development and use. In this paper, we explore some of the reasons for these misperceptions, review the benefits of sound guidelines, and discuss some of the challenges for guideline development in dentistry in Canada

Immunosuppressive effects of (131)I-anti-CD45 antibody in unsensitized and donor antigen-presensitized H2-matched, minor antigen-mismatched murine transplant models

Iodine-131-labeled anti-CD45 antibody has been added to conventional hematopoietic stem cell transplant preparative regimens to deliver targeted radiation to hematopoietic tissues, with the goal of decreasing relapse rates without increasing toxicity. However, higher radiation doses could be delivered to leukemia cells by antibody if the systemic therapy were decreased or eliminated. To examine the ability of (131)I-anti-CD45 antibody to provide sufficient immunosuppression for transplantation across allogeneic barriers, T-cell-depleted BALB.B marrow was transplanted into H2-compatible B6-Ly5(a) mice after (131)I-30F11 (rat antimurine CD45) antibody with or without varying dose levels of total body irradiation (TBI). Groups of five or six recipient mice per (131)I or TBI dose level per experiment were given tail vein injections of 100 microg of (131)I-labeled 30F11 antibody 4 days before marrow infusion, with or without TBI on day 0. Engraftment, defined as > or =50% donor B cells at 3 months posttransplant, was determined by two-color flow cytometric analysis of peripheral blood granulocytes, T cells, and B cells using antibodies specific for donor and host CD45 allotypes and for CD3. Donor engraftment of > or =80% recipient mice was achieved with either 8 Gy of TBI or 0.75 mCi of (131)I-30F11 antibody, which delivers an estimated 26 Gy to bone marrow. Subsequent experiments determined the dose of TBI alone or TBI plus 0.75 mCi of (131)I-30F11 antibody necessary for engraftment in recipient mice that had been presensitized to donor antigens before transplant, a setting requiring more stringent immunosuppression. Engraftment was seen in > or =80% of presensitized recipients surviving after 14-16 Gy of TBI or 12-14 Gy of TBI and 0.75 mCi of (131)I-30F11 antibody. However, only 28 of 69 (41%) presensitized mice receiving 10-16 Gy of TBI alone survived, presumably because of rejection of donor marrow and ablation of host hematopoiesis. In contrast, 29 of 35 (83%) presensitized mice receiving (131)I-30F11 antibody and 10-14 Gy of TBI survived, presumably because the additional immunosuppression provided by estimated radiation doses of 53 Gy to lymph nodes and 81 Gy to spleen from 0.75 mCi of (131)I-30F11 antibody permitted engraftment of donor marrow. These results suggest that targeted radiation delivered by (131)I-anti-CD45 antibody provides sufficient immunosuppression to replace an appreciable portion of the TBI dose used in matched sibling hematopoietic stem cell transplant.

Tooth loss in periodontal patients

OBJECTIVE

To compare tooth loss between patients who received surgical therapy for chronic periodontitis and those who received nonsurgical therapy alone.

METHODS

A retrospective chart study was conducted at Dalhousie University. All patients who had periodontal treatment and were active cases for at least 10 years were included (n = 335). The sample consisted of 120 males (35.8%) and 215 females (64.2%). Ages ranged from 16 to 77 (mean = 46.1 +/- 12.0 years). All patients received nonsurgical therapy; 44.8% received periodontal surgery as well. Variables recorded were demographics, initial attachment loss, treatment type, recall frequency, patient compliance and history of extracted teeth. Independent t-tests or chi-squared tests were used to compare these for surgical and nonsurgical patients. ANOVA was used to test for interactions between initial attachment loss, age, gender, compliance and type of therapy a patient received as reasons for tooth loss.

RESULTS

521 teeth were lost in 69 patients (20.6% of sample). Of teeth lost, 61.8% were due to periodontal disease; 24.8% to caries; 13.2% to other reasons. Patients initially diagnosed with early attachment loss lost an average of 0.37 (+/- 1.33) teeth. Patients diagnosed with moderate attachment loss lost an average of 1.50 (+/- 2.54) teeth and those diagnosed with advanced attachment loss lost an average of 3.11 (+/- 3.01) teeth. Those who received surgical therapy lost more teeth (mean = 1.31 +/- 2.36) than those who received nonsurgical treatment (mean = 0.68 +/- 1.87; p = 0.001). However, initial attachment loss was the only factor that could predict tooth loss. The type of therapy (surgical or nonsurgical) was not statistically significant.

CONCLUSIONS

Most periodontal patients (79.4%) who received treatment at this dental school clinic did not lose any teeth due to periodontal disease over at least 10 years. Although patients who had surgical therapy lost more teeth than those who had nonsurgical therapy alone, this was not an important predictor of tooth loss.

Factors affecting patients' and potential patients' choices among anaesthetics for periodontal recall visits

OBJECTIVES

Dentinal hypersensitivity and recurrent disease may necessitate the use of anaesthetic during periodontal recall visits. However, an aversion to injections may affect patient compliance. The objectives of this study were to determine choices patients and 'potential' patients make when provided with information on the risks and benefits of alternative anaesthetic choices for root planing during periodontal recalls and to examine which factors influence these choices.

METHODS

Using an interactive computer tool, scenarios described the risks and benefits of root planing during periodontal maintenance and the anaesthetic alternatives (no anaesthetic, an experimental thermosetting gel anaesthetic and traditional local infiltration anaesthesia). Compliant patients for whom anaesthesia was recommended during recall cleanings were recruited from private periodontal practices (n=97). General population subjects (potential patients) were recruited by random digit dialing (n=196)

RESULTS

As dental insurance was one of the inclusion criteria, the sample was representative of a working population. Most subjects reported tooth sensitivity (recall 84.5%, general 59.9%). The majority of patients wanted some form of anaesthetic, either gel (recall 82.5%, general 81.0%) or local infiltration (recall 10.3%, general 16.4%). Fifty-five percent of subjects reported moderate or severe pain from their previous dental injection(s). Asked if they were to have a dental needle tomorrow, 52.5% would be somewhat or very anxious. Of those who chose gel, 63.47% would be more or much more willing to return for recall visits if the gel were available. Using multivariate logistic regression, concern about pain and anxiety associated with needles were the only statistically significant characteristics associated with anaesthetic preference.

CONCLUSIONS

Concern about pain and anxiety associated with needles dominates preferences for dental anaesthesia. The overwhelming preference for a non-injectable anaesthetic reveals a strong clinical need for such alternatives.

A phase I/II trial of iodine-131-tositumomab (anti-CD20), etoposide, cyclophosphamide, and autologous stem cell transplantation for relapsed B-cell lymphomas

Relapsed B-cell lymphomas are incurable with conventional chemotherapy and radiation therapy, although a fraction of patients can be cured with high-dose chemoradiotherapy and autologous stem-cell transplantation (ASCT). We conducted a phase I/II trial to estimate the maximum tolerated dose (MTD) of iodine 131 ((131)I)-tositumomab (anti-CD20 antibody) that could be combined with etoposide and cyclophosphamide followed by ASCT in patients with relapsed B-cell lymphomas. Fifty-two patients received a trace-labeled infusion of 1.7 mg/kg (131)I-tositumomab (185-370 MBq) followed by serial quantitative gamma-camera imaging and estimation of absorbed doses of radiation to tumor sites and normal organs. Ten days later, patients received a therapeutic infusion of 1.7 mg/kg tositumomab labeled with an amount of (131)I calculated to deliver the target dose of radiation (20-27 Gy) to critical normal organs (liver, kidneys, and lungs). Patients were maintained in radiation isolation until their total-body radioactivity was less than 0.07 mSv/h at 1 m. They were then given etoposide and cyclophosphamide followed by ASCT. The MTD of (131)I-tositumomab that could be safely combined with 60 mg/kg etoposide and 100 mg/kg cyclophosphamide delivered 25 Gy to critical normal organs. The estimated overall survival (OS) and progression-free survival (PFS) of all treated patients at 2 years was 83% and 68%, respectively. These findings compare favorably with those in a nonrandomized control group of patients who underwent transplantation, external-beam total-body irradiation, and etoposide and cyclophosphamide therapy during the same period (OS of 53% and PFS of 36% at 2 years), even after adjustment for confounding variables in a multivariable analysis.

Current uses of monoclonal antibodies in the treatment of acute leukemia

Advances in the treatment of acute leukemia have been limited by both disease resistance and toxicity. Monoclonal antibodies have been used as a means of targeting therapy to malignant cells in the form of antibody-mediated cellular toxicity, radiation, or other cytotoxic agents. Anti-CD33 and anti-CD45 antibodies have been most extensively studied. Antibodies conjugated with either radioisotopes or cytotoxic moieties have been used as part of stem cell transplant regimens or as induction therapy in patients with relapsed acute myelogenous leukemia (AML), and have demonstrated antileukemic activity with acceptable toxicities.

Periodontal medicine: a new paradigm

Recent evidence indicates that we need to change how we think about the etiology and pathogenesis of periodontal disease. Although bacteria are a necessary factor in the equation, the reaction of the host's immuno-inflammatory system is responsible for most of the destruction found in periodontal disease. Thus, it makes sense that a number of environmental and acquired factors may modify a patient's risk of developing periodontal disease. This paper reviews the scientific evidence for a number of these risk factors including age, genetics, smoking, diabetes mellitus, stress and osteoporosis.

Phase I study of (131)I-anti-CD45 antibody plus cyclophosphamide and total body irradiation for advanced acute leukemia and myelodysplastic syndrome

Delivery of targeted hematopoietic irradiation using radiolabeled monoclonal antibody may improve the outcome of marrow transplantation for advanced acute leukemia by decreasing relapse without increasing toxicity. We conducted a phase I study that examined the biodistribution of (131)I-labeled anti-CD45 antibody and determined the toxicity of escalating doses of targeted radiation combined with 120 mg/kg cyclophosphamide (CY) and 12 Gy total body irradiation (TBI) followed by HLA-matched related allogeneic or autologous transplant. Forty-four patients with advanced acute leukemia or myelodysplasia received a biodistribution dose of 0.5 mg/kg (131)I-BC8 (murine anti-CD45) antibody. The mean +/- SEM estimated radiation absorbed dose (centigray per millicurie of (131)I) delivered to bone marrow and spleen was 6.5 +/- 0.5 and 13.5 +/- 1.3, respectively, with liver, lung, kidney, and total body receiving lower amounts of 2.8 +/- 0.2, 1.8 +/- 0.1, 0.6 +/- 0.04, and 0.4 +/- 0.02, respectively. Thirty-seven patients (84%) had favorable biodistribution of antibody, with a higher estimated radiation absorbed dose to marrow and spleen than to normal organs. Thirty-four patients received a therapeutic dose of (131)I-antibody labeled with 76 to 612 mCi (131)I to deliver estimated radiation absorbed doses to liver (normal organ receiving the highest dose) of 3.5 Gy (level 1) to 12.25 Gy (level 6) in addition to CY and TBI. The maximum tolerated dose was level 5 (delivering 10.5 Gy to liver), with grade III/IV mucositis in 2 of 2 patients treated at level 6. Of 25 treated patients with acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS), 7 survive disease-free 15 to 89 months (median, 65 months) posttransplant. Of 9 treated patients with acute lymphoblastic leukemia (ALL), 3 survive disease-free 19, 54, and 66 months posttransplant. We conclude that (131)I-anti-CD45 antibody can safely deliver substantial supplemental doses of radiation to bone marrow (approximately 24 Gy) and spleen (approximately 50 Gy) when combined with conventional CY/TBI.

The clinical impact of increased sensitivity PT and APTT coagulation assays

To determine how more-sensitive prothrombin time (PT) and activated partial thromboplastin time (aPTT) reagents affected the number and distribution of abnormal test results and whether the increased sensitivity for deficiencies resulted in improved diagnosis of clinically significant coagulopathies, we retrospectively compared preoperative coagulation screening data for 140 children undergoing open heart surgery after the reagent change with a similar group of 135 before the change. The more sensitive reagents resulted in a higher rate of abnormal values, but no increase in the identification of clinically significant hemostatic abnormalities. Of 67 patients with abnormal aPTTs in the group screened with more sensitive reagents, 63 had no further workup. No patients in either group were diagnosed subsequently with a coagulopathy because of unexpected bleeding. An abnormal test result did not predict the need for perioperative blood products. We hypothesize that the high frequency of abnormal aPTTs led to physician "desensitization" about the merit of coagulation screening. Therefore, we question the usefulness of preoperative coagulation screening of the pediatric cardiac surgery patient, particularly since lasting changes in physician perception regarding the clinical significance of abnormal values may lead to missed diagnoses in other settings.

Preference based measurements in dentistry: a review of the literature and recommendations for research

Clinical outcomes are used routinely in dental clinical practice to determine whether or not a patient has exhibited improvement following treatment. While these measures can be useful in comparing therapies in disease specific terms, they do not incorporate outcomes which may be of interest to patients. Preference based outcome measurements, on the other hand, take into account an individual's life style, overall well being and economic resources. There is a number of preference based measures available from the medical field, many of which have been adapted for use in a dental setting. This paper outlines the strengths and weaknesses of these preference based measures, using examples from the dental literature when available. Particular emphasis is placed on an economic tool known as contingent valuation or 'willingness to pay' as a potential technique in the measurement of dental preferences.

Marrow ablative and immunosuppressive effects of 131I-anti-CD45 antibody in congenic and H2-mismatched murine transplant models

Targeted hematopoietic irradiation delivered by 131I-anti-CD45 antibody has been combined with conventional marrow transplant preparative regimens in an effort to decrease relapse. Before increasing the proportion of therapy delivered by radiolabeled antibody, the myeloablative and immunosuppressive effects of such low dose rate irradiation must be quantitated. We have examined the ability of 131I-anti-CD45 antibody to facilitate engraftment in Ly5-congenic and H2-mismatched murine marrow transplant models. Recipient B6-Ly5(a) mice were treated with 30F11 antibody labeled with 0.1 to 1.5 mCi 131I and/or total body irradiation (TBI), followed by T-cell-depleted marrow from Ly5(b)-congenic (C57BL/6) or H2-mismatched (BALB/c) donors. Engraftment was achieved readily in the Ly5-congenic setting, with greater than 80% donor granulocytes and T cells after 0.5 mCi 131I (estimated 17 Gy to marrow) or 8 Gy TBI. A higher TBI dose (14 Gy) was required to achieve engraftment of H2-mismatched marrow, and engraftment occurred in only 3 of 11 mice receiving 1.5 mCi 131I delivered by anti-CD45 antibody. Engraftment of H2-mismatched marrow was achieved in 22 of 23 animals receiving 0.75 mCi 131I delivered by anti-CD45 antibody combined with 8 Gy TBI. Thus, targeted radiation delivered via 131I-anti-CD45 antibody can enable engraftment of congenic marrow and can partially replace TBI when transplanting T-cell-depleted H2-mismatched marrow.

Follow-up of relapsed B-cell lymphoma patients treated with iodine-131-labeled anti-CD20 antibody and autologous stem-cell rescue

PURPOSE

Radioimmunotherapy (RIT) is a promising treatment approach for B-cell lymphomas. This is our first opportunity to report long-term follow-up data and late toxicities in 29 patients treated with myeloablative doses of iodine-131-anti-CD20 antibody (anti-B1) and autologous stem-cell rescue.

PATIENTS AND METHODS

Trace-labeled biodistribution studies first determined the ability to deliver higher absorbed radiation doses to tumor sites than to lung, liver, or kidney at varying amounts of anti-B1 protein (0.35, 1.7, or 7 mg/kg). Twenty-nine patients received therapeutic infusions of single-agent (131)I-anti-B1, given at the protein dose found optimal in the biodistribution study, labeled with amounts of (131)I (280 to 785 mCi [10.4 to 29.0 GBq]) calculated to deliver specific absorbed radiation doses to the normal organs, followed by autologous stem-cell support.

RESULTS

Major responses occurred in 25 patients (86%), with 23 complete responses (CRs; 79%). The nonhematopoietic dose-limiting toxicity was reversible cardiopulmonary insufficiency, which occurred in two patients at RIT doses that delivered > or = 27 Gy to the lungs. With a median follow-up time of 42 months, the estimated overall and progression-free survival rates are 68% and 42%, respectively. Currently, 14 of 29 patients remain in unmaintained remissions that range from 27+ to 87+ months after RIT. Late toxicities have been uncommon except for elevated thyroid-stimulating hormone (TSH) levels found in approximately 60% of the subjects. Two patients developed second malignancies, but none have developed myelodysplasia (MDS).

CONCLUSION

Myeloablative (131)I-anti-B1 RIT is relatively well tolerated when given with autologous stem-cell support and often results in prolonged remission durations with few late toxicities.

Immunotherapy in acute myelogenous leukemia and myelodysplastic syndrome

Disease recurrence following successful bone marrow transplantation remains a major impediment in the management of patients with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). A variety of monoclonal antibodies that deliver drugs or toxins to the site of activity, have been used in an attempt to augment marrow transplantation. Examples of three different monoclonal antibody techniques (naked antibody, drug antibody conjugations, and radiolabeled antibodies) are discussed. CD33 is an attractive antigen to use as a target for treating AML because it is present on most AML cells. Naked antibodies are limited in their ability to kill tumor cells, although studies to date suggest there may be a role in antileukemic therapy for unlabeled anti-CD33 humanized M195 antibody after the tumor burden has been reduced by chemotherapy. Calicheamicin, a novel and toxic drug moiety conjugated to anti-CD33 antibody, is currently under investigation in patients with refractory or relapsed AML. Results from a Phase I investigation were encouraging. Three different radiolabeled monoclonal antibodies have been evaluated in Phase I/II studies--131I-labeled anti-CD33 (p67) antibody, 213Bi-labeled humanized M195 antibody, and 131I-anti-CD45 antibody. CD45 is a cell-surface antigen broadly expressed by all circulating leukocytes and lymphocytes. Initial studies demonstrated that substantially greater doses of radiation could be delivered to targeted organs compared with nontargeted organs using 131I-anti-CD45 antibody. This approach offers the potential for augmenting leukemia therapy without increased risk of toxicity.

Tobacco smoking and periodontal diseases

There is a growing body of scientific evidence indicating that nicotine contributes to the progression of periodontal disease, and is detrimental to healing following periodontal therapy. Smokers show a higher prevalence and greater severity of periodontal disease than non-smokers. Nicotine has toxic effects on peripheral, circulation, which cause gingival vasoconstriction. As a result, a decreased number of immune cells are available in the gingival tissue, which translates into a weakened defence-reparative system. Nicotine can also depress primary and secondary immune response by reducing the chemotactic and phagocytic activities of leukocytes. Clinically, smoking has been associated with increased pocket depths, calculus deposition,alveolar bone loss, acute necrotizing ulcerative gingivitis, and osteoporosis in postmenopausal women. Despite efforts by various investigators, the precise mechanisms underlying the effects of smoking on periodontal status and wound healing remain unresolved. This paper reviews the relationship between smoking and periodontal disease. It also includes a historical overview of the research, and a review of the effects of smoking on oral bacteria, the immune system and exocrine glands. In addition, risk assessment for periodontal disease, clinical features of smokers' periodontitis, response of smokers' periodontal disease to treatment, and ideas for future research are discussed.

The role of radioimmunotherapy in bone marrow transplantation

Radioimmunotherapy offers an exciting new therapeutic modality for patients with recurrent hematologic malignancies and solid tumors resistant to conventional chemotherapy. In this review, a brief overview of tumor radiobiology as well as various obstacles to treatment is presented. Early radiolabeled antibody trials documented myelosuppression as the dose-limiting toxicity. Ongoing trials in solid tumors and hematologic malignancies are testing the hypothesis that myeloablative doses of radiation in conjunction with hematopoietic stem cell rescue will improve long-term survival. For solid tumors, there are many barriers to achieving this goal. The most encouraging trials in metastatic breast cancer have documented significant symptomatic relief and a 50% partial response in patients. In contrast, trials involving hematologic malignancies have produced more impressive results. With a median follow-up of 33 months, 67% of patients with recurrent acute myelogenous leukemia or myelodysplasia treated with radiolabeled antibodies, total-body irradiation, and high-dose chemotherapy remain disease free. Alone, myeloablative doses of radioimmunotherapy have documented a 41% complete response in patients with Hodgkin's disease. Seattle trials with recurrent non-Hodgkin's lymphoma have demonstrated objective responses in 90% of patients, complete responses in 85% of patients, a progression-free survival of 62%, and an overall survival of 93% with a median follow-up of 2 years.

Bone marrow transplantation for sickle cell disease

BACKGROUND

We investigated the risks and benefits of allogeneic bone marrow transplantation in children with complications of sickle cell disease.

METHODS

Twenty-two children less than 16 years of age who had symptomatic sickle cell disease received marrow allografts from HLA-identical siblings between September 1991 and April 1995. The indications for transplantation included a history of stroke (n = 12), recurrent acute chest syndrome (n = 5), and recurrent painful crises (n = 5). Patients were prepared for transplantation with busulfan, cyclophosphamide, and antithymocyte globulin.

RESULTS

Twenty of the 22 patients survived, with a median follow-up of 23.9 months (range, 10.1 to 51.0), and 16 patients had stable engraftment of donor hematopoietic cells. In three patients the graft was rejected and sickle cell disease recurred; in a fourth patient graft rejection was accompanied by marrow aplasia. In 1 of the 16 patients with engraftment, there was stable mixed chimerism. Two patients died of central nervous system hemorrhage or graft-versus-host disease. Kaplan-Meier estimates of survival and event-free survival at four years were 91 percent and 73 percent, respectively. Among patients with a history of acute chest syndrome, lung function stabilized; among patients with prior central nervous system vasculopathy who had engraftment, stabilization of cerebrovascular disease was documented by magnetic resonance imaging.

CONCLUSIONS

Allogeneic stem-cell transplantation can be curative in young patients with symptomatic sickle cell disease.

Barriers to bone marrow transplantation for sickle cell anemia

While allogeneic marrow transplantation is curative therapy for patients with sickle cell anemia, only a small fraction of patients in the United States receive this treatment. We surveyed participants in our multicenter study of marrow transplantation for sickle cell anemia to determine reasons for not proceeding to transplantation. Among the 4848 patients less than 16 years of age with sickle cell anemia that were followed in 22 collaborating centers, 315 (6.5%) patients were reported to meet protocol entry criteria for transplantation, although there was wide variation among the institutions (0.9-36%). Among the 315 patients eligible for transplantation, 128 (41%) had human leukocyte antigen (HLA) typing performed, and of these 44 (14% of those meeting entry criteria) had an HLA-identical sibling. Common reasons for not proceeding with HLA typing in the remaining 187 patients included lack of a candidate sibling donor (76 patients, 24% of those meeting criteria) and lack of financial or psychosocial support (33, 10.5%). Parental refusal (30, 9.5%), physician refusal (13, 4%), history of medical noncompliance (2, < 1%), and other reasons (33, 10.5%) were less frequently cited. To date, 25 patients have been transplanted. Of the remaining 19 patients with HLA-matched donors, seven did not proceed to transplantation because of parental refusal, while the others anticipate a future transplantation (6), have experienced symptomatic improvement (4), or have relocated abroad (2). We conclude that the major barrier to marrow transplantation for sickle cell anemia is lack of an HLA-identical donor. But since only 6.5% of all children with sickle cell disease were considered eligible for transplantation, it is possible that other significant obstacles remain to be identified. For patients reported to meet eligibility criteria, parental refusal and limited financial or psychosocial support were infrequent barriers to transplantation.

Allogeneic marrow transplantation for refractory anemia: a comparison of two preparative regimens and analysis of prognostic factors

From 1990 to 1993 we performed a prospective study of busulfan (16 mg/kg) and cyclophosphamide (120 mg/kg) in 30 patients with refractory anemia (RA) undergoing related (n = 17) or unrelated (n = 13) donor marrow transplantation. Nineteen patients survive disease free (63% 3-year actuarial disease-free survival [DFS]) and no patient relapsed. These results were compared to those of 38 historical controls with RA treated with cyclophosphamide and total body irradiation, of whom 22 are disease-free survivors and 1 relapsed. After correcting for significant variables between the two treatment groups, we found no statistically significant difference in outcome based on preparative regimen. Combining data from these 68 patients plus 2 additional patients with RA treated before 1993 with busulfan and cyclophosphamide, we identified four variables independently associated with improved survival: younger age, shorter disease duration, lower neutrophil count pretransplant, and lower hematocrit pretransplant. We also found that 15 patients 40 to 55 years of age had a 46% 3-year actuarial DFS and 26 patients receiving unrelated or mismatched related donor marrow had a 50% 3-year actuarial DFS. We conclude that there does not appear to be any significant difference in outcome based on preparative regimen in this patient population. In addition, allogeneic bone marrow transplantation may be a reasonable approach to therapy of RA early after diagnosis. However, whether early intervention with transplantation prolongs survival over that expected without transplantation cannot be ascertained with certainty from available data.

The use of diagnostic tests to aid clinical diagnosis

Clinical decision making in dentistry involves some uncertainty and error, but in the absence of good clinical research it is often more of an art than a science. This article demonstrates a way in which clinicians can consistently and effectively base the diagnostic process on scientific evidence. The authors examine the selection and utility of supplemental diagnostic tests, describe the properties of these tests, and explain how test results can be used to augment clinical opinion. To aid the dental clinician in the decision making process, a step-by-step strategy is presented for the detection of squamous cell carcinoma using toluidine blue dye.

Phase II trial of 131I-B1 (anti-CD20) antibody therapy with autologous stem cell transplantation for relapsed B cell lymphomas

25 patients with relapsed B-cell lymphomas were evaluated with trace labelled doses (2.5 mg/kg, 185-370 MBq [5-10 mCi]) of 131I-labelled anti-CD20 (B1) antibody in a phase II trial. 22 patients achieved 131I-B1 biodistributions delivering higher doses of radiation to tumour sites than to normal organs and 21 of these were treated with therapeutic infusions of 131I-B1 (12.765-29.045 GBq) followed by autologous haemopoietic stem cell reinfusion. 18 of the 21 treated patients had objective responses, including 16 complete remissions. One patient died of progressive lymphoma and one died of sepsis. Analysis of our phase I and II trials with 131I-labelled B1 reveal a progression-free survival of 62% and an overall survival of 93% with a median follow-up of 2 years. 131I-anti-CD20 (B1) antibody therapy produces complete responses of long duration in most patients with relapsed B-cell lymphomas when given at maximally tolerated doses with autologous stem cell rescue.

Development of a marrow transplant regimen for acute leukemia using targeted hematopoietic irradiation delivered by 131I-labeled anti-CD45 antibody, combined with cyclophosphamide and total body irradiation

In an attempt to decrease the relapse rate after bone marrow transplantation (BMT) for advanced acute leukemia, we initiated studies using 131I-labeled anti-CD45 antibody (BC8) to deliver radiation specifically to hematopoietic tissues, followed by a standard transplant preparative regimen. Biodistribution studies were performed in 23 patients using 0.5 mg/kg trace 131I-labeled BC8 antibody. The BC8 antibody was cleared rapidly from plasma with an initial disappearance half-time of 1.5 +/- 0.2 hours, presumably reflecting rapid antigen-specific binding. The mean radiation absorbed doses (cGy/mCi131I administered) were as follows: marrow, 7.1 +/- 0.8; spleen, 10.8 +/- 1.4; liver, 2.7 +/- 0.2; lungs, 2.1 +/- 0.1; kidneys, 0.7 +/- 0.1; and total body, 0.4 +/- 0.03. Patients with acute myelogenous leukemia (AML) in relapse had a higher marrow dose (11.4 cGy/mCi) than those in remission (5.2 cGy/mCi; P = .001) because of higher uptake and longer retention of radionuclide in marrow. Twenty patients were treated with a dose of 131I estimated to deliver 3.5 Gy (level 1) to 7 Gy (level 3) to liver, with marrow doses of 4 to 30 Gy and spleen doses of 7 to 60 Gy, followed by 120 mg/kg cyclophosphamide (CY) and 12 Gy total body irradiation (TBI). Nine of 13 patients with AML or refractory anemia with excess blasts (RAEB) and two of seven with acute lymphocytic leukemia (ALL) are alive disease-free at 8 to 41 months (median, 17 months) after BMT. Toxicity has not been measurably greater than that of CY/TBI alone, and the maximum tolerated dose has not been reached. This study demonstrates that with the use of 131I-BC8 substantially greater doses of radiation can be delivered to hematopoietic tissues as compared with liver, lung, or kidney, which may improve the efficacy of marrow transplantation.

Decision making in periodontics: a review of outcome measures

Clinical decisions regarding selection of appropriate periodontal therapy is a multifactorial process involving the assimilation of information from clinical experiences, relevant research, and patient preferences for anticipated outcomes. In order to select the treatment which is most beneficial to patients, a rational, systematic approach to decision making is needed. Clinical experience is a key factor in decision making, but one not easily controlled for. Research to date has focused on clinical or proximate outcomes as a measurement of treatment efficacy, but few of these studies provide the highest level of evidence. While Quality of Life issues play an important role in treatment selection, patient-based outcomes have not been well researched in dentistry. This paper outlines a method clinicians can use to evaluate treatment efficacy studies. In addition, the evidence from longitudinal periodontal treatment efficacy studies is reviewed and the use of patient-based outcome measures is examined.

Evaluating patient perceptions as short-term outcomes of periodontal treatment: a comparison of surgical and non-surgical therapy

To quantify patient perceptions of periodontal therapy, we administered a self-report questionnaire employing a visual analog scale (VAS) to 162 patients following surgical and non-surgical treatments. The questionnaire tested for variables of pain, sensitivity, swelling, function, altered appearance, comparison of postoperative discomfort to restorative treatment (crown or filling), discomfort experienced during the procedure, and resultant disability days. Tests of reliability indicated that with the exception of thermal sensitivity, the variables were significantly reproducible (r > 0.45 for all tests, P < 0.002). Analyses of variance indicated that in contrast to non-surgical treatments, surgery produced significantly more postoperative "discomfort" (P < 0.05) for all variables except experience, sensitivity, altered speech, and comparison to crown preparation. When analyzed according to the type of procedure, soft tissue grafts and osseous surgery produced the most postoperative discomfort. Pearson correlation indicated statistically significant (P < .0001) relationships between pain-related measures (postoperative pain, number of postoperative analgesics, days of pain, days of work missed, and sensitivity). Duration of pain was also found to be related to a history of periodontal treatment (P < .02), but not to previous restorative treatment. These data indicate that patient perceptions of periodontal treatment can be reliably measured and may be used to address appropriateness of care issues.

The use of radiolabeled anti-CD33 antibody to augment marrow irradiation prior to marrow transplantation for acute myelogenous leukemia

Disease recurrence remains a major limitation to the use of marrow transplantation to treat leukemia. Previous transplant studies have demonstrated that higher doses of total-body irradiation result in less disease recurrence, but more toxicity. In this study, the possibility of delivering radiotherapy specifically to marrow using a radiolabeled anti-CD33 antibody (p67) was explored. Biodistribution studies were performed in nine patients using .05-.5 mg/kg p67 trace-labeled with 131I. In most patients initial specific uptake of 131I-p67 in the marrow was seen, but the half-life of the radiolabel in the marrow space was relatively brief, ranging from 9-41 hr, presumably due to modulation of the 131I-p67-CD33 complex with subsequent digestion and release of 131I from the marrow space. In four of nine patients these biodistribution studies demonstrated that with 131I-p67 marrow and spleen would receive more radiation than any normal nonhematopoietic organ, and therefore these four patients were treated with 110-330 mCi 131I conjugated to p67 followed by a standard transplant regimen of cyclophosphamide plus 12 Gy TBI. All four patients tolerated the procedure well and three of the four are alive in remission 195-477 days posttransplant. This study demonstrates the feasibility of using a radiolabeled antimyeloid antibody as part of a marrow transplant preparative regimen and also highlights a major limitation of using conventionally labeled anti-CD33--namely, the short residence time in marrow. Strategies to overcome this limitation include the use of alternative labeling techniques or the selection of cell surface stable antigens as targets.

Monoclonal antibodies in the study and therapy of hematopoietic cancers

Recent advances utilizing monoclonal antibodies to phenotype acute leukemias have revealed no prognostic significance of the expression of lymphoid-associated antigens by acute myeloid leukemia blasts and conflicting results regarding 'biphenotypic' acute myeloid leukemia. Several studies treating patients with refractory lymphoma with immunotoxins reported encouraging results but significant production of anti-mouse or anti-toxin antibody. Radiolabeled antibodies that react with panhematopoietic antigens have delivered selective radiation to marrow, spleen and lymph nodes in animal models and are being used in Phase I studies of marrow transplantation for acute leukemia.

Selective radiation of hematolymphoid tissue delivered by anti-CD45 antibody

The ability to deliver radiation selectively to lymphohematopoietic tissues may have utility in conditions treated by myeloablative regimens followed by bone marrow transplantation. Since the CD45 antigen is the most broadly expressed of hematopoietic antigens, we examined the biodistribution of radiolabeled anti-CD45 monoclonal antibodies in normal mice. Trace 125I or 131I-labeled monoclonal antibodies 30G12 (rat IgG2a), 30F11 (rat IgG2b), and F(ab')2 fragments of 30F11 were injected i.v. at doses of 5 to 1000 micrograms. For both intact antibodies, a higher percentage of injected dose/g (% ID/g tissue) in blood was achieved with higher antibody doses. However, as the dose of antibody was increased, the % ID/g in the target organs of spleen, marrow, and lymph nodes decreased. At doses between 5 and 10-micrograms, % ID/g in these tissues exceeded that in lung, the normal organ with the highest concentration of radiolabel. In contrast, thymus was the only hematopoietic organ in which the % ID/g increased with increasing antibody dose, although at high dose the % ID/g was still far below that achieved in the other hematopoietic organs. Antibody 30F11 F(ab')2 fragments were cleared more quickly than intact antibody from blood and from both target and nontarget organs, although the relationship between increasing antibody dose and decreasing % ID/g in spleen, marrow, and lymph nodes was observed. The time-activity curves for each dose of antibody were used to calculate estimates of radiation absorbed dose to each organ. At the 10-micrograms dose of 30G12, the spleen was estimated to receive a radiation dose that was 13 times more than lung, the lymph nodes 3 to 4 times more, and the bone marrow 3 times more than lung. For each antibody fragment dose, the radiation absorbed dose per MBq 131I administered was lower because the residence times of the fragments were shorter than those of the intact antibody. Thus these estimates suggested that the best "therapeutic ratio" of radiation delivered to target organ as compared to lung was achieved with lower doses of intact antibody. We have demonstrated that radiolabeled anti-CD45 monoclonal antibodies can deliver radiation to lymphohematopoietic tissues with relative selectivity and that the relative uptake and retention in different hematolymphoid tissues change with increasing antibody dose.

Localization of radiolabeled antimyeloid antibodies in a human acute leukemia xenograft tumor model

Acute myeloid leukemia is an attractive disease to treat with radiolabeled antibodies because it is radiosensitive and antibody has ready access to the marrow cavity. In order to evaluate potentially useful radiolabeled antibodies against human acute myeloid leukemia, we have developed a nude mouse xenograft model using the human acute leukemia cell line, HEL. Mice with s.c. xenografts of HEL cells received infusions of radioiodinated anti-CD33 antibody. Examination of the biodistribution of the antibody showed that uptake in the s.c. tumor was maximal [16.9% injected dose (ID)/g at 1 h after infusion] following infusion of 1-10 micrograms of antibody and decreased following infusion of 100 micrograms (6.5% ID/g at 1 h) presumably as a result of saturation of antigen sites. The radiolabel was poorly retained in tumor (4.5-8.2% ID/g at 24 h after infusion). These results were consistent with in vitro studies demonstrating rapid internalization and catabolism of the anti-CD33 antibody. Uptake in tumor could be improved by using either a radiolabel that is retained intracellularly, 111In-DTPA (18.5% ID/g at 24 h), or by targeting a surface antigen that does not internalize upon antibody binding, CD45 (20.5% ID/g at 24 h). These results indicate that this model system will be useful in evaluating the interaction of radiolabeled antibodies with human acute myeloid leukemia cells in an in vivo setting.

Radiolabeled anti-CD45 monoclonal antibodies target lymphohematopoietic tissue in the macaque

Despite bone marrow transplantation, many patients with advanced leukemia subsequently relapse. If an additional increment of radiation could be delivered to lymphohematopoietic tissues with relative specificity, the relapse rate may decrease without a marked increase in toxicity. We have examined the biodistribution of two 131I-labeled monoclonal antibodies reactive with the CD45 antigen in Macaca nemestrina. Three animals received 0.5 mg/kg BC8, an IgG1 of low avidity (6 x 10(7) L/mol). Three received 0.5 mg/kg AC8, an IgG2a of moderate avidity (5 x 10(8) L/mol), and two received 4.5 mg/kg AC8. Estimates of radiation absorbed dose demonstrated that these antibodies could deliver up to five times more radiation to lymph nodes, and up to 2.6 times more to bone marrow, than to lung or liver. The higher avidity AC8 antibody at 0.5 mg/kg was cleared more rapidly from blood and resulted in lower antibody uptake in lymph nodes than did BC8 at 0.5 mg/kg. Increasing the dose of AC8 to 4.5 mg/kg resulted in slower blood clearance and higher lymph node uptake. These studies suggest that radiolabeled anti-CD45 antibodies can deliver radiation with relative specificity to lymphohematopoietic tissues. This approach, in combination with marrow transplantation, may improve treatment of hematologic malignancies.

Reduction of operative morbidity and mortality by combined preoperative and postoperative nutritional support

A previously developed and validated predictive nutritional assessment model (Prognostic Nutritional Index) was applied to a heterogenous surgical population. Without knowledge of the then undeveloped PNI, adequate preoperative nutritional repletion (TPN) was provided on clinical indications alone to 50 of 145 patients with the remaining 95 patients receiving no preoperative total parenteral nutrition. Analysis of the two groups found no baseline differences in nutritional status, type and severity of disease and/or operative therapy, and other potentially important variables. In the high-risk stratified group as defined by admission nutritional assessment and calculated PNI (greater than or equal to 50%), adequate preoperative TPN reduced postoperative complications 2.5-fold (p < 0.01), postoperative major sepsis six-fold (p < 0.005) and mortality five-fold (p < 0.01). Clinical "eyeball" evaluation of nutritional status cannot identify high-risk individuals. This nutritional assessment predictive model (PNI) identifies the subset of operative candidates in whom adequate preoperative nutritional support significantly reduces operative morbidity and/or mortality.

Prognostic nutritional index in gastrointestinal surgery

Based on assessment of 161 nonemergency general surgical patients, a multiparameter index of nutritional status was defined relating the risk of postoperative complications to baseline nutritional status. When applied prospectively to 100 gastrointestinal surgical patients, this index provided an accurate, quantitative estimate of operative risk, permitting rational selection of patients to receive preoperative nutritional support.