No evidence of frequent human immunodeficiency virus type 1 infection in seronegative at-risk individuals

The possible existence of human immunodeficiency virus type 1 (HIV-1) infection in asymptomatic seronegative at-risk individuals was investigated in a prospective study of 55 seronegative high-risk individuals (42 homosexual men and 13 heterosexual individuals) and 32 seronegative hemophiliacs treated with factor VIII or IX concentrates before viral inactivation by heat treatment and systematic screening of blood donations. Tests used include the polymerase chain reaction assay with three primer pairs (one in the gag region and two in the pol region) and tests for serum p24 antigen, anti-nef serology (Western blot), and five biologic markers frequently altered by HIV infection (CD4 lymphocyte count, serum beta 2-microglobulin and neopterin concentration, and serum IgG and IgA concentration). Although 91 of 92 HIV-1-seropositive persons were positive in testing with at least one primer pair, no positive result was observed in seronegative at-risk individuals or in 117 seronegative low-risk controls. No nef antibody was found in seronegative at-risk individuals or seronegative controls, but 44 (47%) of 92 HIV-1-seropositive persons had nef antibodies. These findings do not support the existence of frequent HIV-1 infection in seronegative at-risk individuals.     

Ankle: surface coil MR imaging at 1.5 T

High-field surface coil magnetic resonance (MR) images were obtained of 12 ankles: two from healthy volunteers, seven from patients, and three from fresh cadavers. The cadaver ankles were sectioned in the coronal, sagittal, and axial planes for direct comparison with the MR images. Plain film confirmation of pathologic conditions was obtained in all patients, and five underwent arthroscopy or surgery, or both. MR imaging provided excellent delineation of ligaments and cartilaginous structures in all cases.     

1H nuclear magnetic resonance and clinical studies of interaction of calcium antagonists and hypoglycemic sulfonylureas

The hypoglycemic effect of gliclazide is mainly due to its action on ATP stimulated K+ channels, but the calcium ionophoretic effect of this drug may also be involved in its physiological properties. Using 1H NMR we demonstrated the antiionophoretic effect of nifedipine and diltiazem. We attempted to verify whether this in vitro interaction also occurs in vivo. A clinical trial, was performed on patients treated concomitantly with gliclazide and nifedipine or diltiazem. Results showed that no in vivo interaction occurred. The discrepancy between in vivo and in vitro results may be explained by a too weak plasma concentration in the case of nifedipine and by a large plasma protein binding in the case of diltiazem.     

Evaluation of pediatric transfusion practice using criteria maps

Pediatric blood transfusion practice in a tertiary-care pediatric hospital was evaluated retrospectively by using the technique of criteria mapping. A total of 630 transfusion episodes involving red cell concentrates, frozen plasma (plasma frozen within 24 hours of collection), platelet concentrates, and albumin were reviewed: 243 (86.2%) were reviewed only by a technical assistant, and 87 (13.8%) required additional physician review. Of these, 138 were red cell concentrate transfusions: 79.7 percent of that group were considered appropriate, 11.6 percent of unknown benefit/risk ratio, 5.8 percent inappropriate, and 2.9 percent impossible to evaluate. Some 246 frozen plasma transfusions were reviewed: 42.3 percent were considered appropriate, 32.5 percent of unknown benefit/risk ratio, 17.5 percent inappropriate, and 7.7 percent impossible to evaluate. A total of 139 platelet concentrate transfusions were reviewed: 64.7 percent were considered appropriate, 16.5 percent of unknown benefit/risk ratio, 10.1 percent inappropriate, and 8.6 percent impossible to evaluate. Some 107 albumin transfusions were reviewed: 90.6 percent were considered appropriate, 1.9 percent inappropriate, and 7.5 percent impossible to evaluate. The criteria maps developed for this study were easy for the technical assistant to use, and areas of appropriate and inappropriate pediatric transfusion practice were clearly identified.     

Inhaled nitric oxide in acute respiratory failure: Dose-response curves

Objective To determine the dose-response curve of inhaled nitric oxide (NO) in terms of pulmonary vasodilation and improvement in PaO₂ in adults with severe acute respiratory failure.Design Prospective randomized study.Setting A 14-bed ICU in a teaching hospital.Patients 6 critically ill patients with severe acute respiratory failure (lung injury severity score 2.5) and pulmonary hypertension.Interventions 8 concentrations of inhaled NO were administered at random: 100, 400, 700, 1000, 1300, 1600, 1900 and 5000 parts per billion (ppb). Control measurements were performed before NO inhalation and after the last concentration administered. After an NO exposure of 15–20 min, hemodynamic parameters obtained from a fiberoptic Swan-Ganz catheter, blood gases, methemoglobin blood concentrations and intratracheal NO and nitrogen dioxide (NO₂) concentrations, continuously monitored using a bedside chemiluminescence apparatus, were recorded on a Gould ES 1000 recorder. In 2 patients end-tidal CO₂ was also recorded.Results The administration of 100–2000 ppb of inhaled NO induced: i) a dose-dependent decrease in pulmonary artery pressure and in pulmonary vascular resistance (maximum decrease –25%); ii) a dose-dependent increase in PaO₂ via a dose-dependent reduction in pulmonary shunt; iii) a slight but significant decrease in PaCO₂ via a reduction in alveolar dead space; iv) a dose-dependent increase in mixed venous oxygen saturation (SVO₂). Systemic hemodynamic variables and methemoglobin blood concentrations did not change. Maximum NO₂ concentrations never exceeded 165 ppb. In 2 patients, 91% and 74% of the pulmonary vasodilation was obtained for inhaled NO concentrations of 100 ppb.Conclusion In hypoxemic patients with pulmonary hypertension and severe acute respiratory failure, therapeutic inhaled NO concentrations are in the range 100–2000 ppb. The risk of toxicity related to NO inhalation is therefore markedly reduced. Continuous SVO₂ monitoring appears useful at the bedside for determining optimum therapeutic inhaled NO concentrations in a given patient.     

Familial Nephropathic Non-neuropathic Amyloidosis: Clinical Features, Immunohistochemistry and Chemistry

Classification of familial amyloidosis by the chemical natureof the fibrillar protein has become possible. Most such amyloidogenicproteins so far recognized are variant transthyretins, but twokindreds with the same apolipoprotein AI modification have beenreported. We describe the clinical features of another suchfamily in whom petechial skin rash appeared to be a marker forthe disease, which was non-neuropathic and of the Ostertag-type.Immunohistochemistry showed the protein to be apolipoproteinAI, but allele-specific DNA amplification indicated that itwas not the Arg²⁶ variant previously identified.