Intrinsic factor antibody tests.

The sensitivity of methods to detect antibodies to intrinsic factor was assessed. Five sera of known antibody content were tested in 31 laboratories and 30 sera from patients with pernicious anaemia were tested in one laboratory. Five non-commercial methods and two kits for type I antibodies and one non-commercial method for types I and II antibodies are in current use. Differences in sensitivity of the non-commercial methods for type I antibodies related more to the antigen: antibody ratio in the test system than to the method itself. A radioimmune assay for types I and II antibodies showed the best sensitivity but that of an enzyme linked immunosorbent assay (ELISA) method was poor.     

Intrinsic antiviral immunity

Intrinsic antiviral immunity refers to a form of innate immunity that directly restricts viral replication and assembly, thereby rendering a cell nonpermissive to a specific class or species of viruses. Intrinsic immunity is conferred by restriction factors that are mostly preexistent in certain cell types, although these factors can be further induced by viral infection. Intrinsic virus-restriction factors recognize specific viral components, but unlike other pattern-recognition receptors that inhibit viral infection indirectly by inducing interferons and other antiviral molecules, intrinsic antiviral factors block viral replication immediately and directly. This review focuses on recent advances in understanding of the roles of intrinsic antiviral factors that restrict infection by human immunodeficiency virus and influenza virus.     

固有性抗人类免疫缺陷病毒-1因子的研究

人类免疫缺陷病毒(human immunodeficiency vi-rus,HIV)是获得性免疫缺陷综合征(acquired immu-nodeficiency syndrome,AIDS)的病原体,引起人类致病的主要是HIV-1。人体在HIV-1病毒感染后,主要通过固有性免疫和获得性免疫控制和清除病毒。前者主要有(natural killer cell,NK ce     

Intrinsic control of axon regeneration

Spinal cord injury disrupts the connections between the brain and spinal cord, often resulting in the loss of sensory and motor function below the lesion site. The most important reason for such permanent functional deficits is the failure of injured axons to regenerate after injury. In principle, the functional recovery could be achieved by two forms of axonal regrowth: the regeneration of lesioned axons which will reconnect with their original targets and the sprouting of spared axons that form new circuits and compensate for the lost function. Our recent studies reveal the activity of the mammalian target of rapamycin (mTOR) pathway, a major regulator of new protein synthesis, as a critical determinant of axon regrowth in the adult retinal ganglion neurons[1]. In this review, I summarize current understanding of the cellular and molecular mechanisms that control the intrinsic regenerative ability of mature neurons.     

Intrinsic actions of benzodiazepine antagonists

RO 15-1788 (4-20 mg/kg), both alone and in combination with chlordiazepoxide (5 mg/kg), increased exploratory head-dipping in an holeboard above control levels. This intrinsic action of a benzodiazepine antagonist is not reversed, and is even augmented, by chlordiazepoxide. RO 15-1788 alone had no effect on locomotor activity, but antagonized the sedative effects of chlordiazepoxide. beta-CCE (1 and 2 mg/kg) was without effect on locomotor activity, but the higher dose reduced head-dipping.     

Intrinsic factor secretion from isolated gastric mucosal cells of rat and man — two different patterns of secretagogue control

Intrinsic Factor (IF) secretion was studied using isolated gastric mucosal cells from rat and man. In the rat, IF was localized to the chief cells and its secretion responded most efficaciously to carbachol. DbcAMP and hexoprenaline were less powerful, whereas histamine and pentagastrin lacked any effect. In man, IF secretion derived from the parietal cells and was increasingly enhanced by hexoprenaline, pentagastrin, carbachol, histamine and dbcAMP.In both species, IF secretion differs with respect to its cellular origin and the pattern of secretagogue control: IF release from rat chief cells is due to muscarinic receptor excitation, whereas IF release from human parietal cells responds predominantly to histamine-H₂-receptor activation and seems to be mediated by the cAMP system.     

Intrinsic enzymes of high-density lipoprotein

Several lines of evidence are available to support the protective effects of high-density lipoproteins (HDL) on atherosclerosis. The exact mechanisms by which HDL protects against atherosclerotic disease development are not understood. In addition to its role in the reverse transport of cholesterol from the peripheral sites to the liver for excretion, HDL also carries a number of enzymes that contribute to the remodeling of plasma lipoproteins and to the protection of other lipoproteins against oxidative modification. Many of these enzymes can play a role in determining the composition of circulating HDL, while others appear to affect specific biologic activities associated with HDL. It is not clear whether the concentrations of HDL particles or the activities associated with this class of particles are more important. One of the problems is that HDL constitutes a heterogeneous population of particles, and analytical tools to characterize the various subpopulations are not widely available. In this article, we will review the enzymes that are associated with plasma HDL and possible mechanisms as to how these may contribute to the protective properties of HDL in humans.     

Intrinsic connectivity of human superior colliculus

The superior colliculus (SC) is believed to play an important role in sensorimotor integration and orienting behavior. It is classically divided into superficial layers predominantly containing visual neurons and deep layers containing multisensory and premotor neurons. Investigations of intrinsic connectivity within the SC in non-human species initially led to controversy regarding the existence of interlaminar connections between superficial and deep layers. It now seems more likely that such connections exist in a number of species, including non-human primates. In the latter, anatomical data concerning intrinsic SC connectivity are restricted to a limited number of intracellularly labeled neurons. No studies have been conducted to investigate the existence of intrinsic connections of human SC. In the present study, DiI (1,1-dioctadecyl-3,3,3,3- tetramethylindocarbocyanine perchlorate) and BDA (biotinylated dextran amine) were two tracers used in post-mortem human brains to examine intrinsic SC connections. Injections into the superficial layers revealed tangential connections within superficial layers and radial superficial-layer to deep-layer connections. Within superficial layers, horizontal connections were found over the entire rostro-caudal axis and were mostly directed laterally, i.e. toward the brachium of the inferior colliculus. Superficial-layer to deep-layer connections were more prominent in sections containing the injection site or located close to it. In these sections, an axon bundle having roughly the same diameter as the injection site crossed all deep layers, and individual axons displayed en passant or terminal boutons. The present results suggest that intrinsic connections within superficial layers and radial superficial-layers to deep-layers exist in human SC. The putative roles of these connections are discussed with regard to visual receptive field organization, as well as visuomotor and multisensory integration.     

Intrinsic osmosensitivity of subfornical organ neurons

The constancy of plasma osmolality demands that salt and water concentration within the extracellular fluid be constantly monitored and regulated within a few percentage points. The circumventricular organs in general, and the subfornical organ in particular, have long been proposed to be the site of the osmosensitivity. Isolated subfornical organ neurons of male rats were studied using the whole-cell patch-clamp technique and both action potential frequency and whole cell currents were measured as bath osmolality was changed, from 240 to 330mOsm, by altering the amount of mannitol and maintaining the concentrations of electrolytes constant. Out of 64 cells, 66% responded to changes in bath osmolality in a predictable manner, exhibiting a hyperpolarization and decrease in spike frequency in hypo-osmotic solutions and a depolarization and increase in action potential frequency during hyperosmotic exposure. Cells (34%) defined as non-responders exhibited no significant modulation during identical changes in extracellular osmolality. The responses to changing extracellular osmolality were dose dependent; the activity of subfornical organ neurons was significantly modulated by changes in extracellular osmolality of less than 10mOsm. By regression analysis, this osmosensitivity was approximately 0. 1Hz/mOsm change throughout a +/-10mOsm range and was maintained throughout the range of osmolalities studied (270-330mOsm). The mechanism underlying this osmosensitivity remains unclear, although the non-selective cation conductance and the volume-activated chloride conductance do not seem to be involved.This intrinsic osmosensitivity of subfornical organ within the normal physiological range supports the view that this circumventricular structure plays a role in normal osmoregulation.     

Intrinsic asthma and bacterial histamine release

In this study of intrinsic asthma (IA) in children the pathogenic role of bacteria in respiratory disease was elucidated by a basophil histamine liberation technique. Several strains of bacteria caused release of histamine from peripheral leukocytesin vitro. Normal, non-infectious and non-atopic children frequently responded in a similar fashion, although positive responses were less frequent. It seems that two different mechanisms of bacterial histamine release exist: interaction with the basophil-bound IgE and a direct interaction with the cell surface. It is suggested that the histamine release takes place only in the lung of IA patients, where a defective pulmonary barrier could permit the bacteria to enter, but not in healthy individuals.     

Intrinsic thermal resistance of the canine brain

Hyperthermia above a critical threshold results in multisystemic changes that include neurological manifestations of heat stroke. It is unknown if the latter represents an intrinsic thermal sensitivity of the CNS or whether injury is secondary to physiological responses of non-CNS origin. To address this issue, the present work examined functional, structural, and biochemical changes in the CNS of dogs subjected to a thermal dosage immediately below that which induces disseminated intravascular coagulation with secondary multiple organ injury. The experimental approach is previously reported, inducing a 42.5 degrees C, 90 min, whole body hyperthermia while preventing other physiological responses to treatment, including respiratory alkalosis and significant reductions in mean arterial pressure. Functional analyses included neurologic examinations and brainstem auditory evoked potential recordings in the post-treatment interval in both hyperthermic and euthermic control populations. Biochemical and structural analyses examined the expression of 70-kDa heat shock proteins, cytokines, markers of astroglial and microglial injury/activation, evidence of vascular endothelial damage, and evidence of neuronal and axonal injury in brain between 0.5 h and 8 days from the end of the treatment. The only significant change associated with treatment was induction of the major inducible 70-kDa heat shock protein, this being most prominent in the cerebellum with maximal expression at 6 h and a return to baseline by 8 days.Collectively, from these results we suggest that the canine brain is intrinsically resistant to sublethal hyperthermia such that when CNS lesions occur, they do so in the presence of other physiological derangements.     

Intrinsic innervation of porcine semilunar heart valves

Summary In order to provide additional information on the morphology and the functional performance of semilunar valves, the presence of nerve fibers was investigated in the aortic and pulmonary leaflets by AChE techniques, formaldehyde-induced fluorescence methods, en bloc silver nitrate and gold chloride impregnation and electron microscopy.The results show that AChE positive and adrenergic nerve fibers are constantly present in every leaflet of all the animals examined. The pattern of innervation is similar in aortic and pulmonary valves and no differences exist between coronary and non coronary aortic leaflets. Nerve networks extend over the inferior two-thirds of the leaflets: they are composed of myelinated and non-myelinated axons and are mainly located in the ventricular side of the leaflets. Structures resembling free sensory endings can be shown both by light and electron microscopy.The presence in the leaflets of blood vessels and of an intrinsic smooth muscle system suggests that these two components are the most probable targets of the nerve fibers.Thanks are due to the management of the Vismara meat supply company for providing the pigs' hearts