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PubMed1982

Treatment of unobserved trichotillomania by attention-reflection and punishment of an apparent covariant.

Frequent but primarily unobserved hairpulling, by a 3-yr-old girl was followed by a differential reinforcement procedure, attention-reflection, and punishment of thumbsucking, a possibly covarying behavior. Initially, attention-reflection reduced the hairpulling, but not to a clinically significant level. Dramatic decreases in hairpulling were achieved when thumbsucking was punished by application of a "bad tasting" substance. A brief reversal supports the contention that the two behaviors were correlated and suggests that behaviors may be controlled by targeting observable covariants.

Attention↗

PubMed1992

Reticular formation influences on primary and non-primary auditory pathways as reflected by the middle latency response.

Ongoing studies are aimed at identifying the neural pathways responsible for the middle latency response (MLR). These studies involve the analysis of surface and intracranial potentials following pharmacologic inactivation (with lidocaine) of discrete regions of the guinea pig brain. Previous investigations have shown that MLR surface waves recorded over the temporal lobe originate from pathways anatomically and functionally distinct from those that generate MLR waves recorded over the midline, and that both primary and non-primary auditory thalamo-cortical pathways contribute to the guinea pig MLR. The present investigation examines the role of the mesencephalic reticular formation (mRF) in the MLR generating system. Inactivation of the mRF was associated with disruption of the midline response. These waves have been shown to reflect activity from non-primary subdivisions of the thalamo-cortical pathway. Components recorded over the temporal lobe were also affected, consisting of amplitude reduction and latency prolongation without changes in response morphology. Changes in temporal MLR components with mRF inactivation were smaller than those associated with direct inactivation of primary and non-primary subdivisions of the medial geniculate body. These findings indicate that mRF input is essential for normal generation of those components of the MLR thought to reflect both primary and non-primary auditory pathway activity.

Animals↗

PubMed1996

State-dependent cellular activity patterns of the cat paraventricular hypothalamus measured by reflectance imaging.

Activity within the cat paraventricular hypothalamus (PVH) during sleep and waking states was measured by quantifying intrinsic tissue reflectivity. A fiber optic probe consisting of a 1.0 mm coherent image conduit, surrounded by plastic fibers which conducted 660 nm source light, was attached to a charge-coupled device camera, and positioned over the PVH in five cats. Electrodes for assessing state variables, including electroencephalographic activity, eye movement, and somatic muscle tone were also placed. After surgical recovery, reflected light intensity was measured continuously at 2.5 Hz during spontaneously varying sleep/waking states. Sequential state transitions from active waking to quiet waking, quiet sleep and active sleep were accompanied by progressively increased levels of PVH activity. Overall activity was highest during active sleep, and decreased markedly upon awakening. Moment-to-moment activity oscillated in the 0-0.1 Hz range, especially during active sleep and active waking; this oscillation diminished during quiet sleep. Distinct sub-regions of enhanced or diminished activity emerged within the imaged area in a state-dependent manner. We conclude that PVH activity changes with behavioral state in a regionally specific manner, and that overall activity increases during quiet sleep, and is even more enhanced in active sleep. PVH activation could be expected to stimulate pituitary release of adrenocorticotropic hormone (ACTH) and affect input to autonomic regulatory sites. Since ACTH and corticotropin releasing factor elicit arousal, and since the PVH projects to other brain areas which modulate state, we speculate that the PVH plays a role in shaping characteristics of sleep/waking states.

Animals↗

PubMed1986

Observations on dermal blood flow as reflected by technetium-99m pertechnetate clearance.

Skin blood flow as reflected by the clearance rate of intradermal injections of Technetium-99m (99mTc) was studied in the skin of human volunteers and in a variety of clinical situations. In volunteers comparisons between the effect on clearance following intradermal injections of either lignocaine or lignocaine/adrenaline showed that the latter resulted in a dramatic reduction in the clearance rate of the technetium isotope and that such clearance curves exhibited no fast component. Clinical studies in grossly ischaemic skin revealed a similar absence of the fast component of isotope clearance and this was also the case for healed split thickness skin grafts. The dermal isotope clearance was also used in pedicle skin flaps both before and after clamping the axial pedicle in order to derive clearance ratios which would reflect the degree of neovascularisation to the flap. These preliminary observations suggest that the technique is safe, and easy to use in many clinical circumstances. We consider that it offers a valuable method by which changes in dermal blood flow may be quantified, when simultaneous control areas of isotope clearance are also studied. Suggestions are made for further avenues of study.

Adult↗

PubMed1996

Reflectance spectroscopy and geochemical analyses of Lake Hoare sediments, Antarctica: implications for remote sensing of the Earth and Mars.

Visible to infrared reflectance spectroscopic analyses (0.3-25 micromoles) have been performed on sediments from the Dry Valleys region of Antarctica. Sample characterization for these sediments includes extensive geochemical analyses and X-ray diffraction (XRD). The reflectance spectra and XRD indicate major amounts of quartz, feldspar, and pyroxene in these samples and lesser amounts of carbonate, mica, chlorite, amphibole, illite, smectite, and organic matter. Calcite is the primary form of carbonate present in these Lake Hoare sediments based on the elemental abundances and spectroscopic features. The particle size distribution of the major and secondary components influences their detection in mixtures and this sensitivity to particle size is manifested differently in the "volume scattering" and "surface scattering" infrared regions. The Christiansen feature lies between these two spectral regimes and is influenced by the spectral properties of both regions. For these mixtures the Christiansen feature was found to be dependent on physical parameters, such as particle size and sample texture, as well as the mineralogy. Semiquantitative spectroscopic detection of calcite and organic material has been tested in these quartz- and feldspar-rich sediments. The relative spectral band depths due to organics and calcite correlate in general with the wt% C from organic matter and carbonate. The amounts of organic matter and carbonate present correlate with high Br and U abundances and high Ca and Sr abundances, respectively. Variation in the elemental abundances was overall minimal, which is consistent with a common sedimentary origin for the forty-two samples studied here from Lake Hoare.

Antarctic Regions↗

PubMed1987

Development of strategic skills in impulsive and reflective children: a longitudinal study of metacognition.

This study examined the relationships between metamemory and strategic behavior in impulsive and reflective children. One hundred thirty children from the fourth, fifth, and sixth grades participated. Seventy-seven of these children had been tested 3 years earlier on metamemory and cognitive tempo tasks. At pretraining, children were assessed on metamemory, cognitive tempo, summarization skills, and teacher ratings of impulsive behavior in the classroom. Next, children in three experimental groups received prose summarization instructions, summarization instructions in conjunction with metacognitive training about the importance of a reflective approach to learning, or no instructions. Following training, children were again measured on tempo, summarization skills, and teacher ratings of impulsivity. Analyses of strategy maintenance data indicated superior performance for children who had received both summarization and metacognitive training. Causal modeling analyses showed that early metamemory was an antecedent of later strategy acquisition. The dual role of metacognition as a precursor of later strategy acquisition and controller of lower level strategies was highlighted.

Child↗

PubMed1994

Use of near infrared reflectance spectroscopy in the screening for biliary atresia.

Early diagnosis is crucial for treatment and prognosis of biliary atresia (BA). We used near infrared reflectance spectroscopy (NIRS) for screening of BA. Fecal samples were collected from 200 healthy infants and 16 infants for whom either BA or neonatal hepatitis was diagnosed. Diagnoses were made retrospectively by other diagnostic methods, including laparotomy. The samples (0.5 g each) were manually homogenized. Reflected light from the surface of feces was measured by NIRS. Absorbance peak spectra for fecal fat and conjugated bilirubin were determined before the study, and proved to be 730, 1158, and 1210 nm, respectively. Two cutoff points were set in the second-derivative spectrum: the first (> -0.005) at 730 nm for conjugated bilirubin, and the second (< 1.0) at 1,158:1,210 nm for fat (to include all patients with BA). The sensitivity of NIRS in the diagnosis of BA was 100%, and the specificity was 95.2%. The authors conclude that NIRS is a simple, rapid, noninvasive, and precise technique for the early diagnosis of BA.

Biliary Atresia↗

PubMed1976

Reflectance spectra of natural and acrylic resin teeth.

A method has been described for determining the reflectance spectra of teeth at various parts of the tooth surface. The shape and size of the teeth were accounted for by appropriate experimental and mathematical techniques. In all instances where a subtle difference in tooth color was discernible, this difference was also apparent on the corresponding spectra. The spectra of acrylic resin teeth showed characteristic absorption shoulders caused by pigmentation. These shoulders did not appear in the spectra of natural teeth where the reflectivity gradually increased with increasing wavelength. Differences were observed in the colors as well as the spectra of teeth from different shade guides which were marked with the same shade number by the manufacturer. The method may be applied for control of the color quality of artificial teeth as well as the selection of pigments in order to obtain an appropriate shade range and to reduce effects of metamerism.

Acrylic Resins↗

PubMed1990

Arterial levels of oxidized glutathione (GSSG) reflect oxidant stress in vivo.

Neutrophil-related, oxidant-mediated injury to the pulmonary microvasculature appears to follow endotoxemia, cutaneous thermal injury, and ischemia-reperfusion injury to the liver or intestine. Glutathione is an important endogenous intracellular oxygen radical scavenger. Plasma concentrations of oxidized glutathione (GSSG) reflect oxidant injury resulting from an overdose of certain oxidatively metabolized drugs. The purpose of this investigation was to evaluate plasma GSSG as an indicator of oxidant stress resulting from activation of the endogenous inflammatory response. An established model of neutrophil- and oxidant-related acute lung injury following intestinal ischemia and reperfusion in rats was used. Intestinal ischemia was induced by clip occlusion of the superior mesenteric artery (SMA) for 120 min. Reperfusion resulted from SMA clip removal. Following reperfusion for 0, 15, or 120 min, plasma GSSG levels in portal vein, inferior vena cava (IVC), and aorta were obtained. Plasma GSSG was undetectable in sham animals and those with intestinal ischemia alone. Following reperfusion, all plasma samples had significant elevations in GSSG. Aortic plasma GSSG after 15 min of reperfusion was significantly elevated compared to both portal vein and IVC plasma GSSG. These data suggest that oxidant stress after intestinal reperfusion is reflected by elevations in plasma GSSG. The step up in plasma GSSG across the pulmonary vascular bed, a site of known oxidant injury, suggests that plasma GSSG may be a useful marker of oxidant stress in vivo, particularly with regard to the pulmonary microvasculature. This simple in vivo approach to assessing oxidant stress related to inflammatory tissue injury may have the potential to be of significant use in the clinical setting.

Animals↗

PubMed1994

Levels of viral glycoprotein reflect enhanced effectiveness of combined drug treatments.

A chemosensitivity assay with small replicate Mm5mt/cl C3H mammary tumor cell cultures was developed to determine whether changes in viral antigen expression and release into culture fluids could be utilized as an in vitro measure of single and combined drug effect. The measurement of drug concentrations required for identical 50% reductions in viral antigen levels (ED50s) allowed the dosage-dependence of the same drug to be compared alone and in combination drug treatments. The 52,000 MW viral envelope glycoprotein (gp52) of the mouse mammary tumor virus (MMTV) was measured in culture fluids of control and drug-treated cultures while cell density was simultaneously determined by cell staining and OD 664 mu determination. While extracellular gp52 levels and cell density increased over 72 hours in control cultures, dose-dependent declines in both parameters provided dual measures of effect for combination CAF treatment [cyclophosphamide: doxorubicin (Adriamycin): 5-fluorouracil], combination CMF treatment [cyclophosphamide: methotrexate: 5-fluorouracil] and single component treatments of these combinations. Comparison of ED50s for gp52 reduction revealed that each drug's ED50 concentration was lower in combination treatment than it was in single treatment. In combined drug treatments, the ED50 of doxorubicin was lowered from 5.17 microM to 0.36 microM, that of 5-fluorouracil was lowered from 0.69 microM to 0.22 microM and that of methotrexate was lowered from 15 nM to 1.65 nM. Reductions of ED50 in combined drug treatments argued for drug synergisms in these combinations. When drug concentrations, rather than gp52 reductions, were fixed at identical levels in single and combined treatments, additional declines in gp52 levels reflected the enhanced effects of CAF and CMF combinations over single drug treatments. When the anti-estrogen, tamoxifen, was added to CAF and CMF treatments, further declines in gp52 levels (below CAF and CMF levels) reflected the fact that these hormone-augmented treatments were more effective than either hormone or combination chemotherapy alone. These results indicate that decreases in extracellular levels of MMTV gp52 can be utilized in this in vitro assay as an alternative measure of chemotherapeutic effect for evaluating the synergistic or antagonistic nature of drug or hormone interactions and as a tool for in vitro optimization of combined drug effect.

Adenocarcinoma↗

PubMed1985

Do cyclic AMP concentrations in saliva reflect PTH biologic activity?

The aim of this study was to investigate whether the concentration of cAMP in saliva might reflect the biologic activity of parathyroid hormone (PTH), as nephrogenous levels of cAMP reflect parathyroid function. Patients with primary hyperparathyroidism (HPT) with elevated levels of PTH, nephrogenous cAMP, and serum calcium were found to have cAMP levels not significantly different from control subjects. When the levels of these parameters were reduced following parathyroidectomy, salivary cAMP concentrations were not affected. Similarly, an oral calcium loading test (which decreased both PTH and nephrogenous cAMP in normal subjects) failed to influence salivary cAMP levels. Basal salivary cAMP concentrations were low in secondary hyperparathyroid patients due to chronic renal failure and rose almost fivefold following dialysis despite the stable plasma cAMP levels and salivary flow rate. We conclude that salivary cAMP concentrations do not appear to be influenced by changes in circulating biologically active PTH. However, salivary cAMP concentrations do change in response to certain perturbations; this suggests that they are regulated by some other modulator(s).

Adolescent↗

PubMed1988

Laser reflectance: hazard in the dental operatory.

Reflected CO2 laser light (10 W) is a hazard to oral and surrounding tissues at distances up to 7.0 cm from the focal point. We advise the use of low-reflective instruments and protective shielding during laser treatment.

Carbon Dioxide↗

PubMed1989

Peak N160 of rat flash evoked potential: does it reflect habituation or sensitization?

Flash evoked potentials recorded from awake rats contain a negative peak occurring about 160 msec after the flash (N160). This peak has been associated with a specific level of arousal, and/or habituation by various authors. The current studies attempted to determine whether changes in N160 amplitude which accompany repeated testing reflect processes associated with sensitization or habituation. This paper describes experiments in Long-Evans hooded rats which demonstrate the effects of repeated testing, varying stimulus intensity, varying stimulus frequency, and discharging an alarm bell before and during a test session. Repeated testing produced increases in N160 amplitude which were greater at high than low stimulus intensities. Repeated exposure to the test chamber without flashing did not alter N160 amplitude, nor did altering stimulus rate within the range of 0.5 to 4.0 Hz. Discharging an alarm increased N160 amplitude. Taken together, the data suggest that amplitude of N160 more closely reflects sensitization to the stimulus than habituation to either the stimulus or any feature of the test situation.

Animals↗

PubMed1986

Elevated antigalactosyl antibody titers reflect renal injury after gold or D-penicillamine in rheumatoid arthritis.

Titers of circulating antigalactosyl antibodies (a-Gal Ab) were assessed by passive hemagglutination using rabbit red blood cells in 40 normal subjects, in 14 patients with immunodeficient states, in 47 patients with active rheumatoid arthritis (RA), and in 15 patients with an Henoch-Schönlein disease (HS). Titers of controls ranged from 1:16 to 1:64. All immunodeficient patients exhibited very low titers (1:1). On the contrary, the existence of an enhanced humoral immune response status, as observed in RA, was not reflected by a parallel increase of a-Gal Ab titers. However, in this disease, a strong relationship existed between titers exceeding control values (greater than 1:64) and the prior occurrence of renal injury under gold or D-penicillamine therapy. Lastly, the discovery of elevated titers (greater than 1:64) in HS only when renal involvement occurred further suggests that such antibodies reflect a renal injury.

Acquired Immunodeficiency Syndrome↗

PubMed1981

Chronic amphetamine: tolerance and reverse tolerance reflect different behavioral actions of the drug.

Chronic administration of amphetamine (AMPH) has been reported to produce tolerance to the drug's behavioral effects in some paradigms (self-stimulation, discriminative stimulus, self-administration) and an enhanced effect or reverse tolerance when other behaviors are monitored (locomotor activity, stereotypy). The present study investigated whether the two phenomena are, in fact, related to the particular behavior monitored or reflect the marked differences in the injection regimens (1X vs. 3X daily injections) used to produce the phenomena. The effects of chronic AMPH administered once or three times daily on AMPH facilitation of self-stimulation responding and on the locomotor stimulant and stereotypy-producing effects of the drug were assessed. Regardless of the injection regimen used, chronic AMPH resulted in an enhancement of the locomotor stimulant effects of the drug as well as a more rapid onset and greater intensity of the stereotypy produced. In the self-stimulation paradigm, only the 3X daily regimen significantly reduced the effectiveness of a challenge dose of AMPH (tolerance), although the 1X regimen produced effects that were qualitatively similar but quantitatively less. Perhaps behavioral tasks in which tolerance develops reflect the mood-altering properties of the drug in humans whereas a process similar to reverse tolerance may underlie the increased susceptibility to psychoses elicited by the drug with repeated use.

Amphetamine↗

PubMed1992

Reflectance method for simple determination of proteinase activity in microliter samples of a complex serum-like fluid.

A technique using an optical instrument, a reflectometer, for quantitative determination of proteinase activity in microliter samples of complex serum-like fluids, e.g., crevicular exudate from single sites, was developed. The technique allowed the use of various proteins as enzyme substrate. The reflectometer measures the mass of a layer, such as protein, adsorbed to a reflecting surface. This is done by measuring the reflected light intensity of the p-polarized light beam on a surface. We used methylized silicon surfaces that were coated with fibrinogen, alpha 2-macroglobulin, or hemoglobin as enzyme substrates. The test solution was incubated overnight in a basin made in an agar gel applied on the top of the protein-coated surface. In 82 exudates from periodontitis sites, with pocket depths greater than or equal to 6 mm, fibrinogenolytic activity corresponding to 1 microgram ml-1 of trypsin and pronase P was found in 20% of the samples.

Endopeptidases↗

PubMed1984

Interrupted reflection fibre optic communication device for the severely disabled.

The difference between light reflected from the open eye and that reflected from the closed lid is detected by means of an optic fibre attached to a spectacle frame. That difference is processed electronically to produce a pulse train which may be interpreted either subjectively by a 'listener', or physically for the purpose of controlling external devices. Involuntary blinks may be suppressed. Potential developments of the technique are discussed.

Biomedical Engineering↗

PubMed1985

Brainwave signatures--an index reflective of the brain's functional neuroanatomy: further findings on the effect of EEG sensorimotor rhythm biofeedback training on the neurologic precursors of learning disabilities.

Eight boys, ages 7 years 11 months to 15 years 3 months, were provided with long-term--symptom duration--sensorimotor rhythm biofeedback training for the remediation of their learning disabilities. Concurrently, the simultaneous recording of five frequency bands of brainwave activity (5 Hz, 7 Hz, 10 Hz, 12 Hz and 14 Hz), from one active electrode equidistant from reference and ground, was intended to provide a glimpse of the 'brainwave signature' reflective of the dynamic and synergistic processes involved in such cerebro-neural activation and the brain's global response to such an alteration in the sensorimotor subnetwork. Overall, the main effect of this procedure, for the biofeedback and subsequent conditioning of increased 14 Hz neural discharge patterns over the central Rolandic cortex in a clinical office setting, seems to be to increase bilateral sensorimotor transactions resulting in substantive remediation of the learning disabilities of the recipients of such training--by way of internally exercising of, and/or recruitment of additional neural activation within, the sensorimotor subnetwork/matrix. Observation of the changing brainwave signatures showed a tendency for decreased slow wave activity concomitant with increases in fast wave activity, for cases with a Full Scale I.Q. within the range of 76 and 85; with those cases with a Full Scale I.Q. within the range of 102 and 116 exhibiting increased amplitudes over most of the monitored bands, but with the increases being much less at the slower frequencies. It is noteworthy that those four subjects with either a significant Verbal greater than Performance, or Performance greater than Verbal, I.Q. Score discrepancy exhibited no less than a 40% greater increase in the lower of the two I.Q. scores; indicating that this SMR training procedure also resulted in an increased symmetry in the interhemispheric interactions reflective of the higher cortical functions for these no longer learning disabled boys.

Adolescent↗