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Biomedical subjects

D Peterson

Publications and source records attributed to D Peterson.

14 recordsLinked to original sources
PubMed1992

Does chronic fatigue syndrome predispose to non-Hodgkin's lymphoma?

Chronic fatigue syndrome, an illness that frequently is associated with abnormalities of cellular immunity, has been reported anecdotally to be associated with an increased incidence of lymphoid hyperplasia and malignancy. This report describes an initial analysis of population-based cancer incidence data in Nevada, focusing on the patterns of non-Hodgkin's lymphoma prior to and subsequent to well described, documented outbreaks of chronic fatigue syndrome during 1984-1986. In a study of time trends in four age groups, the observed time trends were consistent with the national trends reported in the Surveillance, Epidemiology, and End Results Program. No statistically significant increase attributable to the chronic fatigue syndrome outbreak was identified at the state level. Additional studies are in progress analyzing the data at the country level, reviewing patterns in other malignancies, and continuing to monitor the cancer patterns over subsequent years.

Adolescent↗
PubMed1992

Cloning, expression, and nucleotide sequence of glgC gene from an allosteric mutant of Escherichia coli B.

The Escherichia coli B mutant strain CL1136 accumulates glycogen at a 3.4- to 4-fold greater rate than the parent E. coli B strain and contains an ADPglucose synthetase with altered kinetic and allosteric properties. The enzyme from CL1136 is less dependent on the allosteric activator, fructose 1,6-bisphosphate, for activity and less sensitive to inhibition by AMP than the parent strain enzyme. The structural gene, glgC, for the allosteric mutant enzyme was selected by colony hybridization and cloned into the bacterial plasmid pBR322 by insertion of the chromosomal DNA at the PstI site. One recombinant plasmid, designated pKG3, was isolated from the genomic library of CL1136 containing glgC. The cloned ADPglucose synthetase from the mutant CL1136 was expressed and characterized with respect to kinetic and allosteric properties and found to be identical to the enzyme purified from the CL1136 strain. The mutant glgC was then subcloned into pUC118/119 for dideoxy sequencing of both strands. The mutant glgC sequence was found to differ from the wild-type at the deduced amino acid residue 67 where a single point mutation resulted in a change from arginine to cysteine.

Allosteric Regulation↗
PubMed1992

Effect of superoxide dismutase and catalase on regional dysfunction after exercise-induced ischemia.

This study was designed to test the hypothesis that the oxygen free radical scavengers superoxide dismutase (SOD) and catalase may reduce myocardial "stunning" after exercise-induced ischemia. To test this hypothesis, 8 mongrel dogs performed treadmill exercise for 10 min in the presence of a flow-limiting coronary artery stenosis. Regional left ventricular function was measured with ultrasonic microcrystals implanted to measure regional wall thickening. Regional myocardial perfusion was measured with radioactive microspheres. The combination of SOD (5 mg/kg iv) and catalase (5 mg/kg iv) did not affect heart rate, blood pressure, coronary artery flow, or regional myocardial blood flow at rest, during exercise, or in the postexercise period. SOD and catalase had no effect on regional wall thickening at rest before exercise. During exercise in the absence of a coronary artery stenosis, thickening was slightly lower during SOD and catalase infusion (27 +/- 11.0 vs. 30.8 +/- 11.5%, SOD vs. control P = 0.05). During exercise in the presence of a coronary artery stenosis, there was no difference in thickening. Infusion of SOD and catalase affected neither the transient rebound function occurring early after exercise nor the prolonged period of stunning. These results indicate that the myocardial stunning that follows exercise-induced ischemia is unlikely to be mediated by oxygen free radicals.

Animals↗
PubMed1992

Vitamin B12 and folate status of a selected group of free-living older persons.

Vitamin B12 and folate status was determined in 50 male and 47 female free-living subjects (65-77 years) in winter and summer. The mean intake calculated from 3-day food records met the Canadian recommended intake (RNI) for both gender and season, however, probability analysis of dietary data revealed a number of subjects at risk of deficiency. Although the mean plasma levels were within the acceptable range for both vitamins, some 9 to 14% of individual subjects had folate plasma levels below normal. Fewer subjects had subnormal plasma vitamin B12 levels. Although mean values for dietary intake and plasma concentration of folate and vitamin B12 may indicate nutritional adequacy, a proportion of an older population may be at nutritional risk.

Aged↗
PubMed1992

Clinical, epidemiologic, and virologic studies in four clusters of the chronic fatigue syndrome.

BACKGROUND: The purpose of this study is to provide a case definition of chronic fatigue syndrome in an outbreak occurring in the Nevada-California region to evaluate candidate etiologic agents and observe the natural history of the illness. METHODS: Patients diagnosed as having chronic fatigue syndrome were studied by repeated interviews, questionnaires, and blood collection over a 3-year period. Serum samples were tested for antibodies to Epstein-Barr virus, human herpesvirus-6, and human T-lymphotropic viruses I and II. Leukocytes from typical cases were also assayed for human T-lymphotropic viruses I and II. RESULTS: Cases were defined as persons who had: (1) severe persistent fatigue following an acute illness appearing in an individual with no previous physical or psychological symptoms; (2) presenting signs and symptoms of an acute infection; (3) severe and persistent headache and/or myalgias; and (4) abrupt change in cognitive function or the appearance of a new mood disorder. After 3 years of follow-up, almost all study subjects were able to return to pre-illness activity. None of the viruses evaluated--human T-lymphotropic viruses I and II, Epstein-Barr virus, or human herpesvirus-6--could be etiologically linked to these outbreaks. CONCLUSION: Clinical features of outbreaks of chronic fatigue syndrome differ sufficiently to suggest different etiologic agents. Giardiasis appears to have precipitated one of the four clusters in this study but the cause(s) of the other three outbreaks is as yet uncertain. The overall prognosis of chronic fatigue syndrome is usually favorable.

Antibodies, Viral↗
PubMed1979

The fortune of a capacious spinal canal.

Injury to the spine may be either osseous, neural, or both. The neurological deficit may or may not be a reflection of the severity of the osseous injury. Patients having wide canals are more likely to have less neurological dysfunction than those having narrow canals.

Adolescent↗
PubMed1977

Hb Leiden-beta (0) thalassemia in a Chinese with severe hemolytic anemia.

The first case of Hb Leiden (alpha2beta2 6 or 7 Glu---O)-beta (0) thalassemia in a young patient with chronic severe hemolytic anemia, which improved after splenectomy, is described. His parents were Chinese. The patient's blood showed no Hb A or normal beta chains when no blood transfusion was given. His mother was heterozygous for beta(0) thalassemia, and his father and brother had a trait for the unstable Hb Leiden. The Hb Leiden level of the father was 22.6% and that of the brother was 19.3%. It is probable that the abnormal hemoglobin in this Chinese family resulted from an independent gene mutation, unrelated to the one found in 2 Caucasian families reported earlier.

Adolescent↗
PubMed1977

Hemoglobin Tak in a newborn Malay.

The trait condition for hemoglobin Tak, was found in a 4-day old newborn Malay who suffered from severe neonatal jaundice. The beta chain of the abnormal hemoglobin was elongated by 11 residues at the C-terminus and had the same structure as reported for Hb Tak. The mother was heterozygous for this abnormal hemoglobin, the father was normal. The mother and child, 4 years later, did not show clinical or hematological symptoms except definitely increased resistance of their erythrocytes to hypotonic saline solutions and slight anisopoikilocytosis. The abnormal gene in the two reported Thai families and in our Malay family may have the same origin.

Hemoglobins, Abnormal↗
PubMed1976

Contour interaction and temporal masking in strabismus and amblyopia.

Visual acuity of amlyopic eyes, measured under binocular viewing conditions, was improved by reducing the contrast of targets presented to the normal eye. Improvement was also obtained by adjusting the temporal relationship between inputs to the normal and amblyopic eye. Optimal acuity was obtained by alternately presenting targets to the two eyes at rates centered about 2 and 7 Hz. These results are interpreted in terms of binocular contour interaction and metacontrast suppression. They suggest that a portion of the amblyope's acuity loss during binocular viewing conditions results from excessive masking by the dominant normal eye.

Amblyopia↗
PubMed1975

The mythology of various hepatitis A virus isolates.

Several types of viral hepatitis may exist. Hepatitis A (MS-1 type) can be transmitted to marmosets and chimpanzees. Virus-like particles, which may be parvo- or enteroviruses and which have been demonstrated in feces of this type of hepatitis, do not share cross-reacting antigens with hepatitis B but do cross-react with fecal hepatitis A antigen. Hepatitis A (GB type), which also does not cross-react with hepatitis B, is not antigenically identical with MS-1; it can be transmitted to marmosets and it may be similar to non-type A/non-type B post-transfusion hepatitis. Hepatitits B does not cross-react either with HA particles, the faecal hepatitis type A antigen or with the MS-1 or GB strains; it can be transmitted to chimpanzees and rhesus monkeys but not to marmosets.

Animals↗
PubMedDate not supplied

Hepatitis in marmosets.

Some species of marmosets are susceptible, not only by parenteral inoculation but also by oral exposure, to human hepatitis A virus present in sera or feces. The stools of animals inoculated parenterally or orally contained fecal antigen during certain times of the incubation period and the early, acute phase of the disease; viruslike particles were present in feces of orally infected animals and such feces were infectious when inoculated into marmosets. The fecal antigen crossreacted both with the fecal virus particles and the immune-adherence antigen (see also papers by Purcell et al and Hilleman et al). The MS-1 and CR-326 strains of hepatitis A appeared antigenically similar or identical whereas the GB strain was antigenically different and may be associated with the recently defined type of hepatitis termed hepatitis C or hepatitis non-A/non-B. On repeated challenge hyperegic responses with diffuse liver cell necrosis occurred in some immune animals and this phenomenon must be taken into account in any future vaccination studies.

Animals↗
PubMedDate not supplied

A roentgenological evaluation of the relationship between segmental motion and malalignment in lateral bending.

OBJECTIVE: A radiographic study was undertaken to determine the relationship between static vertebral malalignment and segmental lumbar motion in lateral bending. DESIGN: Survey. SETTING: Chiropractic college student health center and private chiropractic clinic. PARTICIPANTS: 249 subjects: 114 with low back pain, 29 asymptomatic with no history and 106 asymptomatic with history. Of these, 194 were freshman volunteers and 55 were new private clinic low back pain patients. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Net lumbar segmental tilt and rotation in lateral bending: corrected and uncorrected for segmental malposition with the patient standing in the upright neutral position. RESULTS: There was moderate to good negative correlation of malalignment with segmental tilt motion and segmental motion asymmetry (r = -.42 to -.89, p less than .001). Correlation of malalignment with motion from the ideal neutral segmental position of perfect alignment was modest (r = .16-.42). A large variation in segmental motion was found for all segmental malalignments. CONCLUSIONS: This study suggests that malalignment is associated with segmental tilt motion in lateral bending, although large subject variability greatly compromises predictability on an individual basis. This study also indicates that segmental malposition may complicate the palpation of active range of motion. This is because the malalignment itself may facilitate a greater arc of segmental motion in the direction of comparative restriction in movement from the ideal neutral position to the extreme of lateral flexion.

Adolescent↗