A general multiple-compartment model for the transport of trace elements through animals.

Multiple-compartment models employed in the analysis of trace element transport in animals are often based on linear differential equations which relate the rate of change of contaminant (or contaminant concentration) in each compartment to the amount of contaminant (or contaminant concentration) in every other compartment in the system. This has the serious disadvantage of mixing intrinsic physiological properties with the geometry of the animal. The basic equations on which the model presented here is developed are derived from the actual physical process under way and are capable of separating intrinsic physiological properties from geometry. It is thus expected that rate coefficients determined through this model will be applicable to a wider category of physiologically similar animals. A specific application of the model for the study of contamination of sheep--or indeed for any ruminant--is presented, and the temporal evolution of contaminant concentration in the various compartments of the animal is calculated. The application of this model to a system of compartments with changing geometry is also presented.     

Immunological effects of tumor vaccines: II. T cell responses directed against cellular antigens in the viral oncolysates

Peripheral blood mononuclear cells (PBMC) from patients with epithelial adenocarcinoma of the ovary treated in vivo with tumor vaccines administered as viral oncolysates (VO) exhibited significant proliferative responses in vitro to VO as well as to cellular oncolysates (CO). These responses were dependent on the concentration of VO or CO. VO consisted of lysates from the same ovarian tumor cell lines 2774 and CaOV3 infected in vitro with the avirulent strain of influenza virus A/PR8/34. CO were lysates from the same ovarian tumor cell lines without virus. Depletion experiments with the OKT3 monoclonal antibody plus complement demonstrated that these proliferative responses are T cell specific and under the control of the HLA-D region. Furthermore, these T cell responses are directed against both tumor tumor cellular components and tumor HLA class I molecules. These responses can be detected as early as two weeks after the first intraperitoneal injection of VO and reach a maximum 12-16 weeks after the first application of VO for treatment. PBMC from ovarian patients that received in vivo VO exhibited insignificant proliferative responses to CO prepared from human fibroblasts or tumor cell lines of hematopoietic origin. In contrast, they exhibited significant proliferative responses to CO prepared from a human cervix tumor cell line. These results demonstrate systemic T cell activation by antigens in the tumor vaccines in patients with epithelial ovarian carcinoma after in vivo intraperitoneal administration of VO.     

The effect of naloxone on the preoperative gastric volume and pH

The effect of 4 mg oral naloxone on preoperative gastric volume and pH of gastric aspirate was studied in a double-blind, randomized study. Twenty patients received 10 ml of naloxone (4 mg) mixed with 10 ml of orange juice, and 20 patients received 10 ml of isotonic saline mixed with 10 ml of orange juice, 2 h before surgery. Gastric content was obtained immediately after intubation of the trachea. No significant difference in gastric volume and pH of gastric aspirate was found between the two groups. It is concluded that naloxone does not affect gastric emptying and gastric acid secretion to a degree great enough to protect against aspiration of gastric contents into the lungs.     

Magnetic field tomography of coherent thalamocortical 40-Hz oscillations in humans.

This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible the three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, we illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects.