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Biomedical subjects

R Erickson

Publications and source records attributed to R Erickson.

At least 19 recordsLinked to original sources
PubMed1993

Migration of epithelium during phenytoin-dependent gingival overgrowth in mice.

A small cavity was made in the mesiopalatal area of the maxillary first molar adjacent to the gingiva. Mice were maintained on 40 mg/kg phenytoin (or on diluent for control) by daily intraperitoneal injections. After 9 weeks, light microscopic observations revealed that in experimental mice, epithelial cells migrated towards the cavity and covered it. In controls, epithelial cell migration towards the cavity did not occur. For scanning electron microscopic (SEM) studies, specimens were fixed in 4% glutaraldehyde in 0.1 M phosphate buffer, pH 7.2, for 2 hours, dehydrated, critical point dried and coated with gold. The surface of the outer gingival epithelium of experimental and of control mice showed a honeycomb arrangement of the microridges suggesting their keratinized nature. Epithelial cells lining the cavity showed well marked macroridges along their borders. Parallel microridges were observed on the upper surface of these cells suggesting that they were non-keratinized. It was concluded that the migrating epithelial cells, that covered the cavity during phenytoin-dependent gingival overgrowth, were of the non-keratinized type.

Animals↗
PubMed1992

Study of the major phenotype of large granular T-cell lymphoproliferative disorder.

Six cases of large granular T-cell lymphoproliferative disorder with a selected immunophenotype (CD3+, CD4-, CD8+, CD16+) were studied to characterize a homogeneous group of patients. It was found that most of these patients did not exhibit the clinical features frequently described in large granular T-cell lymphoproliferative disorder--recurrent infection, rheumatoid arthritis, and splenomegaly. The laboratory tests usually positive in large granular T-cell lymphoproliferative disorder, including rheumatoid factor and anti-nuclear antibodies, also were frequently negative. The pathognomonic features were found to be neutropenia and large granular lymphocytosis with positive killer cell markers. All six cases showed T-cell receptor gene rearrangement that indicated a monoclonal proliferation of lymphoid cells, which were natural killer-like T cells by immunophenotyping. B cells were essentially absent in all cases. It should be emphasized that bone marrow aspirates are as informative as peripheral blood samples for the diagnosis of large granular T-cell lymphoproliferative disorder; indeed, phenotypes of blood and marrow in one case were identical in terms of percentages of markers. In this selected group of patients, the clinical courses were indolent with uncomplicated outcomes. In three patients, chemotherapy did not induce an obvious clinical response, but all patients' conditions remained stable with only supportive care.

Adult↗
PubMed1992

Effect of concurrent chest pain assessment on retrospective reports by cardiac patients.

The purpose of this study was to examine the effect of a concurrent record of chest pain episodes on later completeness and accuracy of verbal recall. Patients included 23 men and eight women, ages 43 to 76 years from a private cardiology practice who were randomized into experimental (n = 16) and control (n = 15) groups. Following an initial interview, experimental patients were instructed in using a Chest Discomfort Diary in the home setting to record eight categories of information about each episode of chest pain experienced during the next 7 to 10 days. At the end of that time, both groups were interviewed about a specific typical episode of chest pain that had occurred; patients who did not have chest pain during the study period described an episode experienced prior to the initial interview. Experimental patients recalled their chest pain more completely than controls (P = 0.007), whether it had occurred during or prior to the study period. Experimental patients who had pain (n = 11), and thus actually used the diary, accurately recalled the duration, intensity, description, and treatment of the typical episode but were often inaccurate regarding their mood and the total number of episodes they had experienced. The findings suggest that a concurrent diary offers one method of teaching patients how to report their chest pain symptoms and may improve the completeness and accuracy of those reports.

Aged↗
PubMed1991

Functional projections from striate cortex and superior temporal sulcus to the nucleus of the optic tract (NOT) and dorsal terminal nucleus of the accessory optic tract (DTN) of macaque monkeys.

The nucleus of the optic tract (NOT) and the dorsal terminal nucleus of the accessory optic tract (DTN) have been recognized to be relevant structures for optokinetic and vestibuloocular reflexes. NOT-DTN neurons relay visual information to the vestibular nuclei via the nucleus prepositus hypoglossi and to the flocculus via the dorsal cap of the inferior olive. It has been previously shown that in carnivores the NOT-DTN receives information from primary visual cortical areas in addition to the direct retinal input. In this study we demonstrate the presence and some functional characteristics such as latency and evicacy of considerable cortical projections to the NOT-DTN in macaque monkeys. In anaesthetized and paralyzed monkeys NOT-DTN neurons were identified physiologically and tested for cortical input by electrical stimulation in various cortical areas. Successful sites of stimulation to activate NOT-DTN neurons orthodromically lie in the primary visual cortex (V1) and in the motion-processing areas in the superior temporal sulcus (STS). In contrast, electrical stimulation in area V4 and in parietal areas in most cases did not yield orthodromic responses. Overall latencies of action potentials elicited by stimulation in V1 were 0.5 ms longer than those elicited from STS. These short latency differences between V1 and STS stimulation suggest a direct projection from both V1 and STS to the NOT-DTN. The physiological results were supported by the results of anatomical experiments by using horseradish peroxidase as anterograde tracer. Both injections into V1 and into the lower bank of STS resulted in anterogradely labelled fibers and terminals around the recording sites of direction-specific NOT-DTN neurons. This paper is a first step in clarifying the significance of corticofugal projections from individual areas involved in the analysis of visual motion for the optokinetic reflex.

Animals↗
PubMed1991

Measurement of dentin permeability and wetness by use of the Periotron device.

The ability of the Periotron device to measure changes in dentin permeability and wetness was evaluated by use of extracted human teeth in vitro. Pulpal pressures were varied from zero to 40 cm H2O for simulation of different pulpal tissue pressures. Non-physiologic pulpal pressures of 703 cm H2O were used for comparison of dentin permeability measurements made with the Periotron device with those made using micropipettes. Measurements made with the Periotron device correlated well with methods used previously for measurement of dentin permeability. The shear bond strength of Scotchbond 2/Silux was measured 24 h after being bonded to dentin held at zero pulpal pressure. There was an inverse correlation between the shear bond strengths of Scotchbond 2/Silux and Periotron values, suggesting that increased wetness decreases the bond strength of that system. The Periotron device offers a new, simple, convenient measure of dentin surface wetness which may be useful in dentin bonding studies.

Adhesiveness↗
PubMed1991

Factors related to accuracy in office cholesterol testing. Iowa Academy of Family Physicians Research Network.

BACKGROUND: There has been growing interest in the performance of diagnostic testing in physician office laboratories (POLs). Since the measurement of cholesterol is a well-defined and standardized laboratory test, it was selected to assess factors related to test accuracy in POLs. METHODS: One hundred thirty-one family practice offices were eligible to participate in the survey. Each was mailed a cholesterol specimen with a standardized value in October 1988. The laboratory characteristics of those POLs with results that were within 10% of the true specimen value were compared with those with results that were greater than 10% in error. RESULTS: Of the 131 POLs, 122 returned an answer for the unknown specimen. Ninety-eight (80%) were within 10% of the true value, and 114 (93%) were within 15%. Factors that were related to lower error rates (more likely to be within 10% total error) were whether the laboratory performed more than 25 laboratory tests per day, participated in a proficiency testing program, and ran daily quality controls, as well as the type of instrument the laboratory used. CONCLUSIONS: Overall performance of the POLs compared favorably with reference laboratories; however, running controls and participating in a proficiency testing program may further improve POL test accuracy.

Cholesterol↗
PubMed1990

Cardiovascular effects of caffeine therapy in preterm infants.

Theophylline therapy increases left ventricular output in preterm infants by a combination of positive inotropic and chronotropic effects. The cardiovascular effects of caffeine were evaluated in 20 clinically stable preterm infants. Ten infants received intravenous caffeine citrate with a loading dose of 20 mg/kg and a maintenance dose of 5 mg/kg every 24 hours, and 10 infants were control subjects. Left ventricular output, stroke volume, and heart rate were measured by using a combination of two-dimensional and pulsed Doppler echocardiography and mean arterial blood pressure by oscillometry (Dinamap, Critikon, Division of McNeil Laboratories, Irvine, Calif) before the start and on days 1, 2, 3, and 7 of caffeine therapy and 7 days after discontinuation of therapy. Compared with controls, left ventricular output and stroke volume were significantly increased on days 1 to 7 of caffeine therapy. Caffeine led to an increase in the mean arterial blood pressure on the first 3 days of therapy, but the heart rate did not change. These data indicated that caffeine administration leads to a significant increase in left ventricular output in preterm infants and that this inotropic effect is accompanied by a pressor effect.

Apnea↗
PubMed1989

Deglycosylation of mucin from LS174T colon cancer cells by hydrogen fluoride treatment.

Mucin from xenografts of LS174T human colon cancer cells was treated with anhydrous HF for 1 h at 0 degree C to give a product (HFA) with over 80% of the glucosamine and hexose removed, but retaining some galactosamine, and for 3 h at room temperature to give a product (HFB) devoid of carbohydrate. Rabbit antibodies against HFA bound to HFA much more than to HFB, and bound to native mucin to an intermediate extent. Antibodies to HFB bound to HFB more than to HFA, and did not bind to native mucin. Both HFA and native mucin bound a number of lectins, but HFB did not. By SDS/polyacrylamide-gel electrophoresis and size-exclusion h.p.l.c., native mucin and HFA are of apparent molecular mass greater than 400 kDa, whereas HFB is heterogeneous and of low molecular mass. On Western blots, antibody to HFA detected both high-molecular-mass mucin and a 90 kDa protein in homogenates of LS174T cells. Antibody to HFB detected a major 70 kDa band as well as higher-molecular-mass species. In tissue sections of normal colon and colon cancers, antibody to HFA showed both cytoplasmic and extracellular staining, whereas antibody to HFB generally stained only cytoplasmic antigens. These results indicate that anti-HFB antibody is specific for apo-mucin, whereas anti-HFA antibody is specific for GalNAc-apo-mucin.

Animals↗
PubMed1989

Fine-needle breast aspiration biopsy.

Fine-needle aspiration biopsy of breast lesions is a safe, accurate, well-tolerated procedure that can easily be done in the family physician's office. It has a specificity and positive predictive value of virtually 100 percent, a sensitivity of 53 to 99 percent (median of 89 percent), and a negative predictive value of 80 to 99 percent (median of 93 percent). It is limited by the nature of the lesion, which must be easily palpable, the physician's technical ability, and the availability of a reference cytopathologist. Complications are rare and usually very benign, such as local hematoma. With proper training and understanding of the procedure, many family physicians could easily introduce the procedure into their office practice.

Biopsy, Needle↗
PubMed1987

Cardiovascular effects of a new potent dopamine beta-hydroxylase inhibitor in spontaneously hypertensive rats.

The cardiovascular effects of a new class of potent inhibitors of dopamine beta-hydroxylase (DBH) were evaluated in spontaneously hypertensive rats (SHR). SK&F 102698 [1-(3,5-difluorobenzyl)imidazole-2-thiol] is the prototype molecule of this class of substituted 1-benzylimidazole-2-thiols and is one of the most potent inhibitors of DBH yet described. After acute p.o. administration in conscious unrestrained SHR, SK&F 102698 elicited a dose-dependent decrease in mean arterial blood pressure. The antihypertensive effect was marked by a gradual onset with long duration of activity. The antihypertensive effect produced by SK&F 102698 was accompanied by bradycardia. SK&F 102698 inhibited DBH in vivo as demonstrated by its ability to increase vascular levels of dopamine (DA) while concomitantly decreasing vascular levels of norepinephrine (NE), thus increasing the overall DA/NE ratio. The chronic cardiovascular effects of SK&F 102698 were evaluated in developing SHR. SHR were administered SK&F 102698 p.o. once daily for 9 weeks beginning when animals were 4 weeks of age. SK&F 102698 (50 mg/kg) significantly attenuated the development of hypertension of these SHR. Tolerance to the chronic effects of DBH inhibition was not observed and blood pressures in drug-treated animals were still reduced significantly 20 hr after drug administration. Vascular catecholamine levels were determined in the mesenteric artery of these chronically treated animals. Vascular DA levels were increased 290%, vascular NE levels were decreased 36% and the DA/NE ratio was increased 520%, as compared to controls. Furthermore, hearts weights of SHR receiving SK&F 102698 were approximately 10% lower than controls. The present study demonstrates that in SHR SK&F 102698 is an effective antihypertensive whose effects are mediated by the novel mechanism of DBH inhibition.

Animals↗
PubMed1986

Baseball adaptation for below-elbow prosthesis.

A baseball bat adaptation to improve the handling with below-elbow prosthesis is described. The adaptation consists of a ball and socket joint unit interposed between wrist and hand prostheses. A patient who had forearm amputation successfully used the adaptation to play softball.

Artificial Limbs↗