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PubMed1991

Left ventricular volumes and function immediately after balloon mitral valvoplasty.

To evaluate acute changes in left ventricular volumes and function immediately after successful percutaneous balloon mitral valvoplasty, twenty young patients with isolated rheumatic mitral stenosis (male 9, female 11, mean age 22 +/- 6 years) were studied. The area of the orifice of the mitral valve following valvoplasty, increased from 0.97 +/- 0.27 cm2 to 2.46 +/- 0.75 cm2 (P less than 0.001). No significant change was observed in left ventricular end-diastolic volumes (117 +/- 27 ml to 119 +/- 29 ml, P greater than 0.10), end-systolic volumes (51 +/- 21 ml to 50 +/- 20 ml, P greater than 0.10), ejection fraction (0.57 +/- 0.10 to 0.58 +/- 0.10, P greater than 0.10) and left ventricular meridian wall stress (68 +/- 20.10(3) dynes/cm2 to 65 +/- 14, P greater than 0.10) immediately after valvoplasty. There was no acute change in heart rate, left ventricular end-diastolic pressure, cardiac index and grade of mitral regurgitation. Patients with depressed left ventricular ejection fraction (less than or equal to 0.55, n = 10) and those with normal ejection fraction (greater than 0.55, n = 10) had similar baseline left ventricular end-diastolic volumes and showed no significant change in volumes and ejection fraction after the procedure, although the former group had a greater orificial area after valvoplasty (P less than 0.05). We conclude that an acute increase in the orifice of the mitral valve in patients with rheumatic mitral stenosis is not associated with any significant change in left ventricular volumes and function.

Adolescent↗
PubMed1981

Preservation of retinal structure in aged pigmented mice.

The effects on the retina of advancing age were studied in pigmented mouse strain (C57BL/6J). The mice range in age from 65 days to 1000 days, an age well beyond the mean life span of the population (850 days). The thickness of the neuronal and plexiform layers and the planimetric density and size of the component neurons were assessed in both central (200-500 micrometers from the optic disc) and peripheral (within 200 micrometers of the retinal margin) areas. In addition, the overall size of the retina was determined by measuring its length along the horizontal meridian. Although retinas of albino rodents degenerate extensively during aging [10, 18, 31, 32, 40], in the retinas of pigmented mice neither the central nor the peripheral locus showed either marked thinning of the retinal layers or neuronal loss with advancing age. We suggest that previous findings of severe retinal degeneration in albino rodents during aging can be attributed to their lack of pigment and that pigmented animals offer a more suitable animal model for normal retinal aging.

Aging↗
PubMed1996

Solar-interplanetary circumstances associated with the major events in March and June 1991 and comparison with similar events of previous solar cycles.

The solar activity and geomagnetic storm events of March and June 1991 were associated with the appearance of an enhanced particle flux in the trapped radiation belts as discovered by the CRRES satellite observations and later measured by shuttle radiation detectors. The solar-interplanetary conditions associated with these events appear to be a major sequence of activity near the sun's central meridian generating powerful fast interplanetary shocks resulting in major perturbations to the magnetosphere. The solar-interplanetary events in 1991 are discussed and compared to similar activity in the past such as the events in February 1986, August 1972, July 1961, November 1960, and July 1959.

Earth, Planet↗
PubMed1996

The locus of interference in the Simon effect: an ERP study.

The Simon effect was studied using ERPs and the lateralized readiness potential (LRP). In Experiment 1, visual stimuli requiring left or right hand responses were presented at either side of fixation. In Experiment 2, the empty side was occupied by a distractor. Spatial S-R incompatibility delayed P300 latency in both experiments, as predicted by perceptual interference accounts of the Simon effect. However, the LRP results were not conclusive. The lateralized presentation of visual stimuli (Experiment 1) or targets (Experiment 2) produced a posterior ERP hemispheric asymmetry that spread to central electrodes and obscured the early development of the LRP. Experiment 3 avoided the problem by presenting the stimuli in the vertical meridian, and the LRP showed signs of incorrect response preparation in incompatible trials, in agreement with response-interference models. Both perceptual and response interference may be present in the Simon effect.

Adult↗
PubMed1993

Parabigeminal, pretectal and hypothalamic afferents to rat's dorsal lateral geniculate nucleus. Comparison between albino and pigmented strains.

In adult pigmented and albino rats different fluorescent dyes were injected into the dorsal lateral geniculate nuclei of opposite sides. Differences between the strains occur mainly in parabigemino-geniculate and pretecto-geniculate projections. Both the major contralateral and the minor ipsilateral parabigemino-geniculate projections in albinos were clearly smaller then those in pigmented rats. In pigmented rats but not in albinos the parabigemino-geniculate projections originated mainly from the region where the vertical meridian is represented and contained a small number of neurones projecting bilaterally. In each strain, a small number of retrogradely labelled neurones was found in the ipsilateral and contralateral lateral hypothalami.

Afferent Pathways↗
PubMed1976

Acupuncture and chronic pain mechanisms.

Forty patients with chronic pain below the waist level not amenable to conventional medical and/or surgical treatment were randomly assigned to one or two different methods of acupuncture, after studying the underlying pain mechanisms using a Multidisciplinary Pain Clinic approach and the differential spinal block (DSB). One group received acupuncture needling in the classical acupuncture points referred to as meridian loci needling (MLN) and the other group received tender area needling (TAN) with needles inserted in the dermatomal distribution of the painful areas. The responses between the two groups showed no significant difference. Results were then related to the predetermined somatopsychological basis of the individual's pain problems as classified by the DSB. A group of patinets in whom pain relief occurred upon subarachnoid injection of 0.25% procaine followed by sympathetic blockade or 0.5% procaine injection followed by hypalgesia without motor loss, also reported maximum subjective improvement in their pain level following acupuncture therapy performed at a later time. The other group of patients in whom pain persisted despite sensory and motor blockade (1% procaine) responded very poorly to acupuncture therapy. DSB was found to be complimentary to acupuncture therapy in that it facilitated patient selection for the therapy.

Acupuncture Therapy↗
PubMed1977

Effects of intrasegmental electrical acupuncture on dental pain: evaluation by threshold estimation and sensory decision theory.

The effect of 80 min of low frequency (2 Hz) electric acupunctural stimulation at facial sites on the perception of induced dental pain was evaluated using both pain threshold and sensory decision theory (SDT) procedures. The demonstration of a 187% increase in threshold over a 20 min period of acupunctural stimulation replicated earlier work by Swedish investigators. SDT analyses indicated that the threshold increase reflected a relatively pure sensory change with no significant modification of response bias. However, subjects were able to perceive some of the stimuli presented below threshold level following acupuncture, thus indicating that the threshold concept has been an inadequate description of the phenomenon. This study demonstrated that intrasegmental analgesic stimulation is more efficacious than the extrasegmental meridian point stimulation used in our earlier studies. Possible mechanisms for the observed effect were discussed.

Acupuncture Therapy↗
PubMed1980

Evoked potential assessment of acupunctural analgesia: attempted reversal with naloxone.

The effects of electrical acupunctural stimulation (2 Hz) on pain judgments and evoked potentials are reported for two experiments using dental dolorimetry. In the first experiment subjects received acupuncture at points located in the same neurologic segment as the test tooth. In the second experiment subjects received acupuncture at points on the hands located on acupuncture meridians. In both instances acupuncture resulted in a reduction in pain intensity and smaller evoked potential amplitudes, but naloxone neither reversed the analgesia nor did it affect the evoked potentials. A pilot study was carried out to determine whether manual rather than electrical stimulation would produce an analgesia reversible by naloxone, but it failed to do so. These findings contribute to the growing evidence that acupunctural stimulation significantly reduces pain sensibility in volunteers undergoing dolorimetric testing, but they do not support the hypothesis that endorphin release is a mechanism by which acupuncture exerts analgesia.

Acupuncture Therapy↗
PubMed1984

Correlation between the visual callosal connections and the retinotopic organization in striate-peristriate border region in the hamster: an anatomical and physiological study.

The correlation between the retinotopic organization of receptive fields in the striate-peristriate border region and the distribution pattern of the visual callosal projections was investigated in hamsters with corpus callosum transected 2 days before recording. The results showed that in all the animals studied, the V1/V2 border defined by reversal of receptive fields at the vertical meridian was located in the dense central portion of the visual callosal projection which terminated in cortical regions bordering areas 17 and 18a. These results indicate that there is a close relationship between the striate-peristriate border determined by anatomical and physiological methods. In addition, these data strengthen the suggestion that the pattern of visual callosal projections is a useful and reliable reference system for delineating boundaries of different visual areas in the golden hamster.

Animals↗
PubMed1985

Cytoarchitectural fields and retinal termination: an axonal transport study of laminar organization in the avian optic tectum.

The cytoarchitecture in the retinoreceptive zone of the pigeon optic tectum has been studied in Nissl-stained sections taken in four planes. As suggested by a previous study, two cytoarchitectural fields are present. Reconstructed views of the tectum show that the fields are separated by a narrow transition zone approximating to the tectal representation of the retina's horizontal meridian. In field 1 (which is upper and rostral), sublayer IIb is wide, IIc wide and trilaminate, IId narrow and IIe continuous; in field 2, IIb and c are narrow, IId wide and IIe discontinuous. The distribution of retinal terminals was investigated by the anterograde axonal transport of [3H]proline or horseradish peroxidase from intravitreal injections. The depth distribution of grains or reaction product throughout the entire tectum was quantified by scanning with a microdensitometer. Both autoradiography and horseradish peroxidase transport show two patterns of lamination separated by a narrow transition zone and these two terminal fields correspond closely to the cytoarchitectural fields. In field 1 optic terminals are concentrated in sublayer IIb, superficial c, d, and to a lesser extent in f; in field 2 concentrations are present at the IIb/c boundary, across deep IIc and d, and a small concentration is found IIf. The patterns of retinal termination with depth in the tectum found by axonal transport are compatible with those found by electron microscopy, and are discussed in relation to the optic termination found by other techniques. Study of the time course of axonal transport shows that both radioactive material and horseradish peroxidase are fast transported to all the bands of optic terminals at about 150 mm/day. Horseradish peroxidase gradually accumulates in the retinoreceptive zone, filling clusters of terminals and horizontal processes. At 12 days, it has begun to disappear from the zone and a few diffusely filled profiles, that may be transcellularly labelled, are present. Electron microscope autoradiography of fast transported material shows clusters of grains over optic terminals and preterminals and a percentage density analysis confirms that these profiles are specifically labelled. The two tectal fields each contain the projection from specialized areas of the retina, suggesting functional specialization in the tectum for the processing of different kinds of visual information.

Animals↗
PubMed1989

The corticopontine projection from area 20 and surrounding areas in the cat: terminal fields and distribution of cells of origin as compared to other visual cortical areas.

Visual area 20 in the cat projects to the pontine nuclei and thereby gives input to the cerebellum. The termination of the fibres and the distribution of the cells of origin were studied with anterograde and retrograde transport of horseradish peroxidase-wheat germ agglutinin. Fibres from area 20 terminate ipsilaterally in the medial half of the rostral three-quarters of the pontine nuclei. The labelled fibres occur in multiple well-restricted patches usually some distance away from the peduncle. The retrogradely labelled cells in areas 20a, 20b, and the adjacent posterior suprasylvian visual area were quantitatively mapped. Areal borders were placed according to the maps of Tusa and Palmer (J. comp. Neurol. 193, 147-164) and Updyke (J. comp. Neurol. 246, 265-280). In terms of cortical densities (cells per mm2 of cortex) area 20a is among the visual areas with the highest densities of corticopontine neurons (data from other visual areas from the author's previous works). Densities are 30-60% lower in area 20b than in 20a. The posterior suprasylvian visual area was found to be among the visual areas with the lowest densities of corticopontine neurons. Due to the small size of the areas investigated, the total number of corticopontine cells within them is small compared to many other areas. Within areas 20a and 20b, cortical densities are higher in the representation of visual space below than above the horizontal meridian. Furthermore, cortical densities are generally somewhat higher in the region devoted to central vision compared to regions devoted to the visual periphery. Since the part of cortex in areas 20a and 20b devoted to central vision is weakly over-represented also in terms of cortical volume, it follows that the "visual field density" (cells per degree of visual field) of corticopontine cells is highest in the central visual field representation. The finding of an over-representation of central vision compared to peripheral vision in the corticopontine projection from areas 20a and 20b is particularly interesting in conjunction with previous findings in other visual areas. In the cortical representations of central vision, areas with high magnification factors (i.e. areas that greatly emphasize central vision in terms of cortical volume, such as areas 17, 18, and 19) have relatively low cortical densities of pontine projecting cells, whereas areas with low magnification factors (such as areas 20a, 20b, and some of the lateral suprasylvian visual areas) have relatively high cortical densities. The "visual field density" of corticopontine neurons appears therefore to be fairly constant from area to area as concerns central vision.

Animals↗
PubMed1996

The organization of visual corticocortical connections in early postnatal kittens.

We tested the hypothesis that, in newborn kittens, superficial layers of the extrastriate cortex receive more specific patterns of corticocortical innervation from the striate cortex than deep layers. First, we injected retrogradely transported tract-tracers at a range of depths in area 18 to label area 17. All injections were of similar tangential diameter and were in the same region of rostral area 18, where the visual field 10-20 degrees below the horizontal meridian is represented. Injections that involved only the superficial layers of area 18 labelled cells mainly in the superficial layers (future layers 2-4) of area 17, across a region that was 2-3 mm wider than the diameter of the injection site in the rostrocaudal direction. Injections that involved all layers of area 18 labelled cells in both superficial and deep layers (5 and 6) of area 17, across a region that was 6-9 mm wider than the diameter of the injection site in the rostrocaudal direction. These values demonstrate that, in neonates, the convergence of projections from area 17 to the superficial layers of area 18 is less than that to the deep layers of area 18. The lower values for convergence obtained by injecting only the superficial layers of area 18 in kittens were similar to those obtained by injecting all layers of area 18 in adult cats; the values obtained by injecting all layers of area 18 in kittens were much higher. Second, we injected the full depth of area 17 in newborn kittens with labels that travel anterogradely and retrogradely. Confirming the conclusions from the use of retrograde tracers, these focal injections produced very widespread labelling of the deep layers of area 18, but much more localized and topographically organized labelling of its superficial layers. These results indicate that there is a considerable postnatal improvement in the accuracy with which corticocortical cells in striate visual cortex target appropriate regions in extrastriate cortex, in agreement with previous findings. They also demonstrate that this change occurs mainly among those striate cortical neurons that innervate a wide region of the deep layers of extrastriate cortex at birth. The innervation of the superficial layers of extrastriate cortex is much more accurate from the outset.

Age Factors↗
PubMed1994

Thalamic neuron theory: theoretical basis for the role played by the central nervous system (CNS) in the causes and cures of all diseases.

The Thalamic Neuron Theory (TNT) postulates that the central nervous system (CNS) is involved in all disease processes, as the CNS not only processes incoming physical and chemical information from the periphery, it also sends out physiological commands to the periphery in order to maintain homeostasis for the entire body. Inherent in its capacity to learn and adapt (i.e. to habituate) is the CNS' ability to learn to be sick (pathological habituation) by looking in certain deranged central neural circuitries, leading to chronic disease states. These pathologically habituated states can be reversed by dehabituation through manipulation or modulation of the abnormal neural circuits by physical means (physical neuromodulation) like acupuncture, or chemical means (chemoneuromodulation) such as Chinese medicine, homeopathy or other modern medical techniques in a repetitious manner to mimic the habituation process. Chemoneuromodulation can also be achieved by delivery of minute amounts of pharmacological agents to specific sites in the periphery such as the acupuncture loci. It is hypothesized that humoral and neurotrophic factors and cytokines could be highly effective neuromodulating agents. TNT assumes the blue print for embryological development is embodied in the phylogenetically ancient part of the brain. This primordial master plan, organized in the form of a homunculus, possibly encased in a small nucleus, retains control over the subsequently evolved parts of the brain so that the entire CNS functions like a composite homunculus which controls the physiological functions of the entire body. TNT further postulates that the master homunculus takes the shape of a curled up embryo with its large head buried close to its pelvic region, with its large feet and hands crossed over to the contralateral sides. Neuronal clusters along a neuronal chain in the homunculus represent acupuncture points in the periphery. The neuronal chain itself represents a meridian and Chi is nothing more than the phenomenon of neurotransmissions. Certain new theoretical concepts such as the principles of Adynamic Stat and Bilaterality are also presented. Many difficult to explain clinical observations in modern medicine, Chinese herbal medicine, acupuncture and homeopathy can now be adequately explained using TNT. Based on this model, new therapeutic techniques can be launched to combat a whole host of intractable diseases.

Central Nervous System↗
PubMed1988

Rat hypothalamic arcuate neuron response in electroacupuncture-induced analgesia.

Electroacupuncture (EA) effects on activity of arcuate neurons of the hypothalamus (ARH) and on magnitude of the digastric electromyogram (dEMG) in the jaw opening reflex were investigated, in both p-chlorophenylalanine pretreated and normal Wistar rats. EA stimulation (300-500 microA, 5 msec pulses, for 15 min) was delivered unilaterally to a meridian Ho-Ku point of anesthetized rats at 3, 45 and 100 Hz. In control animals, EA stimulation at 3, 45 or 100 Hz induced long-lasting suppression of the magnitude of the dEMG activity and changed the spontaneous firing rate of most of the ARH neurons: the rate either increased (type I) or decreased (type II). After low-frequency stimulation, there were significantly more type I neurons than type II; after high-frequency stimulation, there were significantly more type II neurons than type I. In serotonin-depleted rats, however, high-frequency stimulation suppressed dEMG activity only slightly and induced a smaller proportion of type II neurons.

Acupuncture Therapy↗
PubMed1994

Inhalation of resuspended road dust, but not ammonium nitrate, decreases the expression of the pulmonary macrophage Fc receptor.

Pulmonary macrophages (PM) play a key role in the immune defenses of the lung. When stimulated, PM express Fc receptors (FcR) that regulate the immune response. PM were assayed for FcR expression following subchronic inhalation exposure of adult Fischer 344 rats to either 90 micrograms/m3 nitrate (NH4NO3), 300 micrograms/m3 road dust, or clean air, for 4 h/day, 4 days/week, for 8 weeks. PM were lavaged from the lungs and attached to glass coverslips for 18 h. PM FcR were labelled with rat IgG conjugated with cyanine-3. For each exposure, FcR were determined with a Meridian ACAS 570 confocal cytometer by imaging the fluorescence of 50 cells. We found that the IgG binding to FcR (in arbitrary fluorescence units, FU, per cell) for PM from road dust exposed rats was less (835 +/- 39.3 FU/cell) than that for PM from both ammonium nitrate or clean air-exposed rats (1115 +/- 58.0 FU/cell and 1123 +/- 46.6 FU/cell, respectively). While acid incubation conditions in vitro (pH 5.5 for 30 min to simulate the acid environment of ammonium nitrate inhalation) resulted in a 16% decrease in IgG binding (P < 0.05), IgG binding to PM from acid aerosol exposed rats was no different than the IgG bound to PM from clean air-exposed rats. PM exposed to road dust in vivo expressed 25% fewer FcR (P < 0.05). Three-dimensional images of PM failed to show any major alterations in FcR distribution. These preliminary results indicate cellular recognition of antibody-immune complexes may be impaired by subchronic exposure to road dust, which could decrease the immune response of road dust exposed animals.

Animals↗
PubMed1987

Comparison of seven kits for detection of rotavirus in fecal specimens with a sensitive, specific enzyme immunoassay.

A sensitive, specific enzyme immunoassay (SSEIA) was compared to four commercial, enzyme-linked immunosorbent assay (ELISA) kits and three latex agglutination assay (LAA) kits: (1) Rotavirus EIA, International Diagnostic Laboratories (IDL), (2) Pathfinder, Kallestadt (KAL), (3) Rotavirus Bio-EnzaBead, Litton (LIT), (4) Rotazyme II, Abbott (RTZII), (5) Slidex Rota-Kit, bioMerieux (SRK), (6) Meritec-Rotavirus, Meridian (MER), and (7) Rotalex, Medical Technology Corporation (RLX). The SSEIA was chosen as the reference method due to its greater sensitivity in comparison to immunoelectron microscopy and polyacrylamide gel electrophoreses of viral RNA segments. Upon evaluation of 136 specimens (of which 44 were positive by SSEIA), the ELISA kits (LIT, KAL, IDL, and RTZII) had sensitivities of 80%, 98%, 91% and 84%; specificities of 95%, 78%, 100%, and 88%; positive predictive values (PPV) of 88%, 68%, 100%, and 77%; and negative predictive values (NPV) of 91%, 99%, 96%, and 92%. When compared with SSEIA, the three LAA tests (SRK, MER, and RLX) had sensitivities of 73%, 75%, and 62%; specificities of 99%, 93%, and 95%; PPVs of 97%, 85%, and 84%; and NPVs of 88%, 89%, and 84%. LAA test results appeared to be reliable, if positive, but the sensitivities of these tests were less than those of the ELISA tests. The ELISA tests that employed specimen specific negative controls were superior in minimizing false positive reactions.

Evaluation Studies as Topic↗
PubMed1988

Incidence of Cryptosporidium in all patients submitting stool specimens for ova and parasite examination: monoclonal antibody IFA method.

The development of a monoclonal antibody to Cryptosporidium oocysts provides a more sensitive detection method than that seen using other diagnostic techniques. Incidence reports on this organism have been based on earlier, less-sensitive methods. In order to determine the numbers of positive patients and stool specimens, every stool specimen submitted for an ova and parasite examination was tested using the Merifluor IFA system (Meridian Diagnostics, Inc). Over a 12-mo period, 2,786 specimens were tested (1,516 patients). Positive specimens (23) were from nine known immunosuppressed patients and from four symptomatic immunocompetent patients. This represents an overall positive rate of 0.86% (patients). In those patients who were not suspected of having cryptosporidiosis (immunocompetent), diagnosis of this infection would not have been accomplished without the use of a sensitive screening method. This data, obtained over a 12-mo period, provides information for those laboratories considering the clinical relevance of screening all stool specimens for this infection. With the development of therapy, early detection of Cryptosporidium will become more important.

Animals↗
PubMed1995

Evaluation of a commercially available ELISA assay for detection of Giardia lamblia in fecal specimens.

A total of 417 fecal samples preserved in 10% buffered formalin and PVA were submitted to a commercial microbiology laboratory only for the detection of Giardia lamblia. Results from fecal specimens collected from 411 patients with gastrointestinal symptoms were compared using the following methods: (a) standard Ova & Parasite (O&P) concentration; (b) Alexon's ProspecT/Giardia enzyme-linked immunosorbent assay (ELISA) test, and (c) Meridian's Direct Fluorescent Antibody (DFA) Stain. In the 29 specimens in which G. lamblia was detected, 10 were O&P, DFA and ELISA positive, 17 were only ELISA positive and two were only Ova & Parasite and Direct Fluorescent Antibody positive. Of the 29 positive specimens, 22 were confirmed as true positives. The ELISA sensitivity was 91% and the specificity was 98%. The expense associated with these methods to detect the presence of Giardia is $11.00, $8.95, and $12.80, respectively. In symptomatic patients, the ProspecT/Giardia ELISA is a cost-effective, rapid, and sensitive method for detecting the presence of G. lamblia in fecal specimens.

Animals↗