Extending the Fellegi–Sunter probabilistic record linkage method for approximate field comparators

Probabilistic record linkage is a method commonly used to determine whether demographic records refer to the same person. The Fellegi–Sunter method is a probabilistic approach that uses field weights based on log likelihood ratios to determine record similarity. This paper introduces an extension of the Fellegi–Sunter method that incorporates approximate field comparators in the calculation of field weights. The data warehouse of a large academic medical center was used as a case study. The approximate comparator extension was compared with the Fellegi–Sunter method in its ability to find duplicate records previously identified in the data warehouse using different demographic fields and matching cutoffs. The approximate comparator extension misclassified 25% fewer pairs and had a larger Welch’s T statistic than the Fellegi–Sunter method for all field sets and matching cutoffs. The accuracy gain provided by the approximate comparator extension grew as less information was provided and as the matching cutoff increased. Given the ubiquity of linkage in both clinical and research settings, the incremental improvement of the extension has the potential to make a considerable impact.     

Detection of circulating crosslinked fibrin derivatives by a heat extraction-SDS gradient gel electrophoretic technique

A technique has been developed to identify and quantitate unique plasmic degradation products of crosslinked fibrin in plasma. In this method, fibrin derivatives are extracted by heat precipitation and dissolved with disulfide bond reduction, after which the crosslinked gamma-gamma chain remnants are identified by SDS-polyacrylamide gradient gel electrophoresis and quantitated by densitometric analysis. A heterogenous group of gamma-gamma chains with molecular weights between 100,000 and 76,000 daltons was identified in lysates of crosslinked fibrin during plasmic degradation in vitro. Three stages of crosslinked fibrin degradation have been arbitrarily defined based primarily on the extent of degradation of these gamma-gamma polypeptide chains. As little as 20 microgram of crosslinked fibrin digests added to 1 ml of normal plasma could be detected by the heat-extraction--gel- electrophoresis technique, identifying the gamma-gamma derivatives with molecular weights of 96,000, 86,000, 82,000, and 76,000 daltons. Plasmic derivatives of gamma-gamma chains were not found in normal plasma, but they were identified in the plasma of patients with disseminated intravascular coagulation and deep-vein thrombosis, both before and in increased quantity during successful thrombolytic therapy.     

Newborn survival: a multi-country analysis of a decade of change

Neonatal deaths account for 40% of global under-five mortality and are ever more important if we are to achieve the Millennium Development Goal 4 (MDG 4) on child survival. We applied a results framework to evaluate global and national changes for neonatal mortality rates (NMR), healthy behaviours, intervention coverage, health system change, and inputs including funding, while considering contextual changes. The average annual rate of reduction of NMR globally accelerated between 2000 and 2010 (2.1% per year) compared with the 1990s, but was slower than the reduction in mortality of children aged 1-59 months (2.9% per year) and maternal mortality (4.2% per year). Regional variation of NMR change ranged from 3.0% per year in developed countries to 1.5% per year in sub-Saharan Africa. Some countries have made remarkable progress despite major challenges. Our statistical analysis identifies inter-country predictors of NMR reduction including high baseline NMR, and changes in income or fertility. Changes in intervention or package coverage did not appear to be important predictors in any region, but coverage data are lacking for several neonatal-specific interventions. Mortality due to neonatal infection deaths, notably tetanus, decreased, and deaths from complications of preterm birth are increasingly important. Official development assistance for maternal, newborn and child health doubled from 2003 to 2008, yet by 2008 only 6% of this aid mentioned newborns, and a mere 0.1% (US$4.56m) exclusively targeted newborn care. The amount of newborn survival data and the evidence based increased, as did recognition in donor funding. Over this decade, NMR reduction seems more related to change in context, such as socio-economic factors, than to increasing intervention coverage. High impact cost-effective interventions hold great potential to save newborn lives especially in the highest burden countries. Accelerating progress requires data-driven investments and addressing context-specific implementation realities.     

Results of the tension-free vaginal tape procedure for stress incontinence: Patient''s perspective

BACKGROUND: To evaluate the results of the tension-free vaginal tape procedure (TVT) from a patient's perspective. METHODS: Between May 1999 and January 2002, 90 patients underwent a TVT for genuine stress incontinence (GSI) and mixed incontinence. Prior to the procedure, GSI was confirmed by clinical examination and urodynamic studies. Results were then audited from patient notes and the same patients were sent questionnaires to examine results from a patient perspective. RESULTS: Overall response rate to the questionnaire was 70 (77%). The mean age of the patients was 50.4 years (range 31-83 years). Sixty-one patients had spinal anesthesia, seven had general anesthesia and two had local anesthesia. Mean hospital stay was 3.36 days (range 2-14 days) and mean period from the operation to the time of the survey and audit was 16.34 months (range 3-28; SD 6.92). Thirty-nine (56%) of the 70 patients who answered said that the operation had cured their incontinence, 16 (23%) had an improvement in their symptoms, 7 (10%) had worsening of their symptoms and 8 (11%) felt that the operation did not make any difference. The overall success rate according to the patients' perspective was 79%, whereas our audit showed an overall success rate of 86% (77% and 82%, respectively, when we compared only the 66 patients who had both notes and replies available for analysis). CONCLUSION: Although a patient's perception regarding the success of TVT tends to differ from that of a clinician, it was not found to be statistically significant (P = 0.22, McNemar test). The TVT is a very successful operation, but realistic cure rates should be offered to patients.     

Paraneoplastische Hypoglykämie beim lokalisierten fibrösen Tumor der Pleura

Zusammenfassung. Der lokalisierte fibr?se Tumor der Pleura ist ein seltener, langsam wachsender, benigner Tumor, der seinen Ursprung von den submesothelialen Stammzellen der Pleura visceralis nimmt. Klinisch findet sich in vielen F?llen ein asymptomatischer Verlauf, wobei jedoch bei wenigen F?llen Tumor-assoziierte Hypoglyk?mien bis hin zum hypoglyk?mischen Koma beobachtet werden. Bei diesen Nicht-Inselzell-Tumoren findet man laborchemisch eine Erh?hung des paraneoplastisch gebildeten IGF-II im Serum, der eine 2–3 fach h?here Wirkpotenz als das physiologische Insulin aufweist. Darüber hinaus kommt es zu einer reduzierten Synthese von IGFBP-3 (insulin-like growth factor binding protein), das durch Komplexbildung die endokrine Wirkung des IGF-II hemmt. Die Therapie der Wahl ist die chirurgische Tumorresektion. In dem hier geschilderten Fall fanden sich bei einem 72 j?hrigen Mann klinisch trotz eines bekannten Diabetes mellitus Typ II ausgepr?gte Hypoglyk?mien. Bei der diagnostischen Abkl?rung fand sich ein von der Pleura visceralis im rechten Hemithorax ausgehender Tumor. Nach der chirurgischen Resektion des Tumors waren diese Hypoglyk?mien nicht mehr nachweisbar.      

Development of spontaneous intracranial hypotension concurrent with grade IV mobilization of the cervical and thoracic spine: a case report

Donovan JS, Kerber CW, Donovan WH, Marshall LF. Development of spontaneous intracranial hypotension concurrent with grade IV mobilization of the cervical and thoracic spine: a case report.Spontaneous intracranial hypotension (SIH) has been clinically defined as the development of severe orthostatic headaches caused by an acute cerebrospinal fluid (CSF) leak. Typically, intracranial hypotension occurs as a complication of lumbar puncture, but recent reports have identified cases caused by minor trauma. We report a case of SIH secondary to a dural tear caused by a cervical and thoracic spine mobilization. A 32-year-old woman with SIH presented with severe positional headaches with associated hearing loss and C6-8 nerve root distribution weakness. CSF opening pressure was less than 5cmH₂O and showed no abnormalities in white blood cell count. Cranial, cervical, and thoracic magnetic resonance imaging revealed epidural and subdural collections of CSF with associated meningeal enhancement. Repeated computed tomography myelograms localized the leak to multiple levels of the lower cervical and upper thoracic spine. A conservative management approach of bedrest and increased caffeine intake had no effect on the dural tear. The headache, hearing loss, and arm symptoms resolved completely after 2 epidural blood patches were performed. Practitioners performing manual therapy should be aware of this rare, yet potential complication of spinal mobilizations and manipulations.     

Body weight is a predictor of biphasic shock success for low energy transthoracic defibrillation

We studied the performance of external chest compression by 20 fourth year medical students on 2 study days, separated by 5-7 weeks, 4-8 months after they had been initially trained in cardiopulmonary resuscitation (CPR). Our hypotheses were (1) that a given individual would perform external chest compressions in the same manner each time CPR was performed and (2) that the pattern of performance of chest compressions would be determined, in part, by the anthropometric characteristics of the rescuer. A Laerdal Skillmeter Resusci-Anne CPR manikin chest compression transducer was interfaced with an analogue-to-digital conversion board in a Macintosh LC III computer. Each subject on each study day performed four cycles of 15 compressions and two ventilations twice, once on a table (which raised the surface of the manikin sternum to 95 cm) and once on the floor. For each individual, on each attempt, we calculated the depth and rate of compressions, duty cycle, peak compression velocity, time to peak compression velocity and time to peak compression depth. In addition, we calculated the regression slope of compression depth versus compression number for each cycle of 15 chest compressions and over four cycles of compressions. Statistically significant correlations were observed between the first and second study days in each of the variables of chest compression measured, indicating that the performance of chest compressions was constant over time for a given individual. We observed that the depth of compression, duty cycle, time to peak compression, time to peak velocity and regression slope of depth of compressions versus compression number were significantly related to the height and weight of the rescuer.     

Analysis of p53 mutations in a large series of lymphoid hematologic malignancies of childhood

p53 mutations are found in a wide variety of cancers, including hematologic malignancies. These alterations apparently contribute to development of the malignant phenotype. We analyzed a large series of lymphoid (330 cases) and a smaller series of myeloid (29 cases) malignancies of childhood for p53 mutations by single-strand conformational polymorphism (SSCP) following polymerase chain reaction. Samples with abnormal SSCP were reamplified and analyzed by direct sequencing method. p53 mutations were detected within the known mutational hotspots (exons 5 to 8) in 8 of 330 lymphoid malignancies, and in none of 29 myeloid malignancies, showing that the frequency of p53 mutations in childhood lymphoid malignancies was very low (8 of 330 cases [2%]). Four of these patients had very aggressive, fatal acute lymphocytic leukemia (ALL). None of 13 infants and none of 48 patients with T-lineage leukemia had detectable p53 mutations in their ALL cells. Exceptionally, p53 mutations were comparatively frequent in a small sample of B-cell non-Hodgkin's lymphomas (2 of 8 cases). Mutations were detected in samples from two patients with ALL at relapse; these were not detected in samples at initial diagnosis from the same patients, suggesting that p53 mutations may be associated with progression to a more malignant phenotype. Seven of eight alterations of p53 were missense mutations, and seven of eight samples may be heterozygous for the mutant p53, indicating that p53 protein may act in a dominant negative fashion.     

Acquired immunodeficiency syndrome-associated non-Hodgkin's lymphomas and other malignancies in patients with hemophilia

Non-Hodgkin's lymphoma (NHL) is the most common human immunodeficiency virus (HIV)-associated malignancy in hemophiliacs. We studied the incidence and clinicopathologic features of NHL in 3,041 hemophiliacs followed at 18 US Hemophilia Centers between 1978 and 1989. Of the 1,295 (56.6%) who were HIV(+), 253 (19.5%) developed acquired immunodeficiency syndrome (AIDS), of whom 14 (5.5%) developed NHL. Three NHL occurred in HIV(-) hemophiliacs, for a 36.5-fold greater risk in HIV(+) than HIV(-) hemophiliacs (P < .001). The NHL incidence rate was 29-fold greater than in the US population by Surveillance, Epidemiology, and End Results (SEER) estimates (P < .001). Between 0 and 4 lymphomas have been observed per year between 1978 and 1989. At presentation 13 (92.9%) of the HIV(+) NHL were extranodal. Ten were stage IV, 1 stage II, and 3 stage IE. Ten (71.4%) were high-grade, 3 (21.4%) intermediate-grade, and 1 (7.1%) was a low-grade B-cell lymphoma. Epstein-Barr virus (EBV) DNA was detected in 36% by in situ hybridization, including one central nervous system (CNS) lymphoma. The mean CD4 cell count at NHL diagnosis was 64/mm3, the mean latency from initial HIV infection was estimated to be 59 months, and the median survival was 7 months. The incidence of basal cell carcinoma in HIV(+) hemophiliacs was 18.3-fold greater than in HIV(-) hemophiliacs (P < .001) and 11.4-fold greater than in the US population (P < .001). In conclusion, incidence rates of NHL and basal cell carcinoma in HIV(+) hemophiliacs are significantly increased over rates in HIV(-) hemophiliacs and over rates in the US population. Clinicopathologic presentation of NHL in HIV(+) hemophiliacs is similar to that in HIV(+) homosexual men.