A point score system for predicting the likelihood of blood transfusion after hip or knee arthroplasty

BACKGROUND: Given the high cost of autologous blood donation for elective surgery, it would be desirable to predict which patients are most likely to benefit from the procedure. The purpose of this study was to develop a point score system for predicting the likelihood of blood transfusion in hip and knee arthroplasty. STUDY DESIGN AND METHODS: A database of 599 patients undergoing elective surgery at a teaching hospital was used for the analysis. Variables were analyzed to determine their univariate association with postoperative blood transfusion. Significant factors were entered into a multiple logistic regression model, and a point score system was developed on the basis of the regression coefficients. Four strata of transfusion risk were constructed. RESULTS: Factors independently associated with blood transfusion included preoperative hemoglobin, type of arthroplasty, primary versus revision surgery, autologous donor status, and patient weight. Four factors were used to create a point score system with four strata. The likelihood of blood transfusion for patients in the four risk strata was 1.7, 11.0, 40.0, and 78.3 percent. The calculated area under the receiver operating characteristic curve was 0.86. CONCLUSION: The likelihood of a postoperative blood transfusion can be predicted by using this simple point score system. Autologous blood donation can subsequently be targeted to the high-risk patients.     

Lack of detection of human immunodeficiency virus type 1 DNA by polymerase chain reaction in the plasma and lymphocytes of seronegative exposed hemophiliacs

Direct detection of human immunodeficiency virus type 1 (HIV-1) DNA in serum or plasma samples has been reported in seronegative as well as seropositive individuals. An alkaline lysis procedure was adapted for polymerase chain reaction (PCR) analysis of plasma specimens. Eighty- five seronegative hemophiliacs, 52 of whom had been exposed to HIV- contaminated blood components, and 19 seronegative at-risk individuals were studied. Each sample was extracted and amplified with SK38/39 gag primers at least three times. Seventy-six samples (72%) were consistently negative for HIV-1 DNA, 24 (22%) were positive only once, and 4 (3%) were positive twice. Genomic DNA from peripheral mononuclear cells was prepared from 12 of 76 negative samples, 18 of 24 samples that were positive once, and 2 of 4 samples that were positive twice and analyzed with both gag and long terminal repeat primers. None (0/32) of these cellular DNAs were positive for HIV-1, which suggests that these seronegative exposed hemophiliacs were not latently infected with HIV-1. In contrast, all (10/10) control cells from seropositive patients were positive with both primer pairs. The detection of HIV-1 DNA in serum or plasma may be prone to a high level of false-positive PCR signals and should be interpreted with caution.     

A Quest For the Relief of Atherosclerosis: Potential Role of Intrapulmonary Heparin--A Hypothesis

Recent progress in the treatment of coronary artery diseaseis reviewed from the standpoint of changes in lifestyle, surgicaltechniques to revascularize the myocardium and a variety ofmedical interventions. Among the medical modalities, heparinappears to have a greater potential than any other agent testedto neutralize the atherogenic process at most of its stages.This potential is supported by success in clinical trials ofheparin administered by intravenous, subcutaneous, pulmonary,sublingual and topical routes. The suggested self-administrationof low-dose heparin by inhalation appears to be well justifiedand easily adaptable to home therapy. The summarized evidencesuggests the need for further clinical trials to test the useof heparin in the prophylaxis of atherosclerotic disease.     

Evidence that several high-frequency human blood group antigens reside on phosphatidylinositol-linked erythrocyte membrane proteins

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired disorder associated with absence of expression of phosphatidylinositol (PI)- linked membrane proteins from circulating hematopoietic cells of multiple lineages. Recent work demonstrated that decay accelerating factor, one such PI-linked protein, bears the Cromer-related blood group antigens. This study demonstrated that other high incidence antigens, including Cartwright (Yta/Ytb), Holley-Gregory (Hy/Gya), John Milton Hagen (JMH), and Dombrock (Doa/Dob), are absent from the complement-sensitive (PNH III) erythrocytes of patients with PNH. The relatively normal, complement-insensitive erythrocytes from the same patients express these antigens normally. Therefore, these antigens most likely reside on PI-linked proteins absent from PNH III, but not PNH I, erythrocytes.     

Acute and long-term effects of massive balloon dilation on the aortic wall and vasa vasorum

To investigate the acute and long-term effects on the vasa vasorum after massive overdilation, canine aortic segments were dilated with Gruentzig balloon catheters to more than 100% over normal size. In the acute study, the significant lumen increase was the result of intimal and medial rupture with stretching and thinning of the adventitia. In these areas, the vasa vasorum were stretched and severed, causing adventitial hemorrhage. In the chronic study, areas of previous subtotal wall rupture with adventitial thinning were repaired by scar tissue. This repair included formation of a neomedia, hyperplasia of the adventitia, and proliferation of the vasa vasorum. No progression of luminal dilatation was seen. This study showed that in subtotal aortic wall rupture, even a severely damaged adventitia is capable of preserving the lumen from further dilatation and rupture until healing. Blood flow to the damaged vessel wall was reestablished by revascularization via capillary budding in the aortic wall.     

Massive symptomatic subependymoma of the lateral ventricles: case report and review of the literature

Subependymomas are benign intraventricular tumors with an indolent growth pattern, which are usually asymptomatic, and most commonly occur in the fourth and lateral ventricles. When symptomatic, subependymomas often obstruct critical portions of the cerebrospinal fluid (CSF) pathway, causing hydrocephalus, and range from 3 cm to 5 cm in size. We report a case of an unusually massive subependymoma of the lateral ventricles treated with subtotal resection, ventriculoperitoneal shunt, and post-surgical radiation. The clinical course, radiographic and pathologic characteristics of this massive intraventricular subependymoma are discussed, as well as the differential diagnosis of lateral ventricular masses and a review of the literature concerning subependymomas.     

Dental material artifacts on MR images

Magnetic resonance (MR) imaging of the head and neck is becoming an important aid in evaluating pathologic conditions of the brain, midface, and pharynx. Certain dental materials cause artifacts during MR imaging of the lower midface. These artifacts can obscure the normal anatomy. This study describes the degree of artifact production caused by various materials commonly used in dental restorations. Of the materials tested, those causing artifacts were made of stainless steel, such as orthodontic bands used for braces, and pins or posts that are commonly drilled into teeth to provide structure or stability before filling. Materials used as temporary or permanent fillings or crowns--such as amalgam, gold alloy, aluminum, microfilled resin, and polyvinyl acrylics--did not cause artifacts in the images.     

The mean and variance of samples of dioptric powers: the basic calculations

Methods are presented for calculating the mean and variance-covariance of a sample of dioptric powers that make proper allowance for the astigmatic component. For the first time the way is open to formal statistical analysis of data on such important topics as refractive error.