Influenza B virus reinfection

Four outbreaks of influenza B infection occurred in Houston, Texas in the years 1976-1984. In the Houston Family Study, age-related infection and illness rates in the recent two epidemics resembled those reported previously. A total of 118 persons, including 35 children followed from birth, were followed longitudinally through this entire period and 331 persons were studied through at least two outbreaks. Fifty-nine (88%) of 67 children studied for four outbreaks were infected and 25% had a second infection; about half of the adults had one infection but only one of 51 was reinfected. Infection rates were proportionally lower for those followed through 2-3 outbreaks. Those with documented infection were protected decreasingly over time against reinfection and associated illness in subsequent epidemics. Such protection decreased in efficacy from 65% after 2-3 years, to 46% after 4-5 years, and to no protection after seven years.     

Pentobarbital pharmacokinetics in patients with severe head injury

Intravenous administration of high-dose pentobarbital has been proposed as a treatment for elevated intracranial pressure refractory to other measures in brain-injured patients. The purpose of this clinical study was to examine the pharmacokinetics of high-dose continuous intravenous infusion of pentobarbital in this critical care setting. Six patients received a 25-34 mg/kg intravenous loading dose followed by a 1-3 mg/kg/h continuous infusion for 61-190 hours. Dosing rates were adjusted based on the patient's clinical status. The mean clearance was 0.72 ml/min/kg, with a volume of distribution (Vd) of 1.03 L/kg and a terminal half-life of 19.1 h. Considerable variation in individual patient parameters was observed. In addition, a change in clearance was suggested in patients requiring a longer infusion duration.     

高效液相色谱法测定右旋儿茶素血浆浓度及药代动力学参数

本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4～5.6%,血浓69.6～1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。     

A randomized comparison of umbilical vein and intravenous oxytocin during the puerperium

Oxytocin was administered in a randomized fashion via either the umbilical or maternal intravenous route. Women who received intraumbilical oxytocin had significantly greater calculated blood loss compared with those who received peripheral administration (P = .01). This greater blood loss was confirmed by a decrease in hematocrit and hemoglobin concentrations after delivery. There was no difference between the groups in the length of the third stage of labor. The incidence of fetomaternal transfusion was higher in the intraumbilical group (P = .07). We conclude that intraumbilical oxytocin is no more beneficial than peripheral administration.     

Production and characterization of genetically engineered antibody molecules

Expression of antibody heavy- and light-chain genes by transfection permits the production of monoclonal antibodies with improved biological and antigen-binding properties. The immunoglobulin genes are placed in vectors containing a gene for encoding a protein that provides a biochemically selectable function in eukaryotic cells; these vectors are transfected into myeloma and hybridoma cells. Selection of drug-resistant cells permits the efficient isolation of the rare cells that express the transfected DNA. By placing heavy and light chains on plasmids with different selectable markers, one can deliver heavy- and light-chain genes simultaneously to the same cell. The transfected immunoglobulin genes are efficiently expressed and the proteins produced are a faithful mirror of the genes that were introduced. Using the standard techniques of genetic engineering and gene transfection, we can now produce antibodies of widely varying structures, including chimeric antibodies with segments derived from different species. These antibodies provide useful reagents to study structure-function relationships within the antibody molecule. Ultimately it will be possible to produce a new generation of antibody molecules with improved antigen-binding properties and effector functions.     

Diffraction tomography by a method of image projections

A method of three-dimensional diffraction tomography based on image projections is derived. Inversion methods based on projections generally are inaccurate due to the spreading nature of the scattered wave. By backpropagating the field onto a single plane in the image region, diffraction effects are reduced and a projection of the weakly scattering object is generated. Consequently, conventional X-ray inversion techniques may be used to image the object. The relationship between the backpropagated field and the projection is derived both for high frequency incident waves and low spatial frequency scatterers. The generalized image kernel allows the use of curved or misaligned recording surfaces. Numerical results are included.     

Evaluation of oxygen desaturation events in singleton pregnancies.

Previous investigators have demonstrated that oxygen desaturation may occur in laboring women. The purposes of this study were to identify groups at risk for desaturation and to seek correlation with newborn outcome. Volunteers in labor were evaluated for oxygen desaturation, analgesic exposure, magnesium sulfate administration, and various medical illnesses. Desaturations were noted more frequently in women exposed to narcotic analgesics, sedatives, and magnesium sulfate. A trend toward more desaturations in the women with preeclampsia was noted. Although desaturations related to narcotic analgesics and sedatives are most likely due to hypoventilation, the mechanism in women treated with magnesium sulfate is uncertain. Maternal peripartum desaturations did not result in unfavorable neonatal Apgar scores, cord blood gas measurements, or neonatal oxygen desaturation values, but the staff was aware of the events and prompt treatment was instituted.     

Toxoplasmosis of the central nervous system in the acquired immunodeficiency syndrome.

BACKGROUND AND METHODS. Toxoplasmosis is the most common opportunistic infection of the central nervous system in patients with the acquired immunodeficiency syndrome (AIDS). To investigate its clinical course, we reviewed the records of 115 patients with AIDS and central nervous system toxoplasmosis treated at San Francisco General Hospital between 1981 and 1990. RESULTS. The most common presenting symptoms were headache (in 55 percent), confusion (52 percent), and fever (47 percent). Focal neurologic deficits were present in 79 patients (69 percent). The median CD4 cell count at presentation was 50 per cubic millimeter (50 x 10(6) per liter). Thirteen of 80 patients with clinical toxoplasmosis (16 percent) and 4 of 18 patients with pathologically proved disease (22 percent) had undetectable antitoxoplasma IgG antibodies by indirect immunofluorescence assay. Of 103 patients, 94 (91 percent) had enhancing lesions on CT. Single lesions were seen in 28 of 103 patients (27 percent) on CT, and such lesions were seen in 3 of 21 patients (14 percent) on magnetic resonance imaging. Over 90 percent of patients who eventually had clinical and radiographic improvement had evidence of improvement by day 14 of therapy. Adverse drug reactions occurred in 71 patients (62 percent) and led to a change in therapy in 50 patients (43 percent). Among the patients who survived a first episode of toxoplasmosis, the median survival was 265 days. CONCLUSIONS. Toxoplasmosis occurs in advanced stages of human immunodeficiency virus infection, and the absence of antitoxoplasma antibodies on immunofluorescence assay does not exclude the diagnosis. The clinical and radiographic response to therapy is usually rapid, but treatment is frequently limited by adverse drug effects.