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Biomedical subjects

B Peterson

Publications and source records attributed to B Peterson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Deficiency of neutrophilic granule membrane glycoproteins in the myelodysplastic syndromes: a common deficiency in 216 patients studied by the Cancer and Leukemia Group B.

Previous studies on neutrophils in patients with the myelodysplastic syndromes (MDS) have indicated deficiencies in the contents of primary and secondary granules. However, the granule membrane remains virtually unstudied despite its essential role in the dynamic function of the cytoplasmic granules. In this study, we examined the membrane glycoproteins of primary and secondary granules of peripheral blood and/or bone marrow neutrophils using the monoclonal antibody H36/71 to CD15 glycoproteins. In addition, myeloperoxidase activity and antigen, elastase and lactoferrin were also studied using cytochemical and immunocytochemical stains. A total of 216 patients were included. Deficiencies of granule membrane glycoproteins were the most common, detected in 49%, followed by myeloperoxidase activity (17%), elastase (16%), myeloperoxidase antigen (9%), and lactoferrin (8%). Multiple deficiencies always included granule membrane deficiency. We conclude that granule membrane defects are common in MDS, may provide a common mechanism for multiple granule deficiencies, and may prove to be an additional abnormality associated with granulocyte dysfunction.

Cytoplasmic Granules↗
PubMed1997

Diminished neurogenic but not pharmacological erections in the 2- to 3-month experimentally diabetic F-344 rat.

The rapid spread of locally restricted neural and hormonal signals among the vast array of largely inexcitable corporal smooth muscle cells is an absolute prerequisite to normal erectile function. And yet the mechanism(s) responsible for this phenomenon is not well understood. As a first step toward a more integrative understanding of erectile physiology and/or dysfunction, an 8- to 12-wk period of experimental diabetes was induced in 2-mo-old male Fischer 344 rats by either intraperitoneal streptozotocin (STZ) injection (35 mg/kg; n = 22) or subtotal pancreatectomy (n = 11). Fourteen age-matched control animals received injection of vehicle only while nine others served as sham-operated control animals. Eight STZ-diabetic animals received insulin replacement. Erectile function was assessed by evaluation of penile reflexes and monitoring of intracavernous pressure responses to both electrical stimulation of the cavernous nerve and intracorporal papaverine or nitroglycerin injection. Intracavernous pressure responses to neurostimulation were significantly attenuated in both STZ-diabetic and subtotal pancreatectomy animals compared with age-matched control animals (P < 0.05). Penile reflexes were also significantly diminished (P < 0.05). Regression analysis revealed that diabetes-related decreases in neurostimulated intracavernous pressure responses were strongly correlated with diminished synaptophysin immunoreactivity in the corpora (P < 0.001; r = 0.88). However, there were no detectable diabetes-related differences in pharmacological erections induced by intracavernous papaverine or nitroglycerin injection. Northern analysis revealed a marked diabetes-related increase in the amount of connexin 43 mRNA measured in frozen corporal tissue. Insulin replacement partially restored (attenuated the loss of) synaptophysin immunoreactivity and maintained neurostimulated intracavernous pressure responses to control levels while having no effect on penile reflexes. These observations may have important implications to the understanding of erectile physiology as well as the etiology of diabetes-related erectile dysfunction.

Animals↗
PubMed1997

Value of molecular monitoring during the treatment of chronic myeloid leukemia: a Cancer and Leukemia Group B study.

PURPOSE: Disappearance of the Philadelphia chromosome during treatment for chronic myeloid leukemia (CML) has become an important therapeutic end point. To determine the additional value of molecular monitoring during treatment for CML, we performed a prospective, sequential analysis using quantitative Southern blot monitoring of BCR gene rearrangements of blood and marrow samples from Cancer and Leukemia Group B (CALGB) study 8761. PATIENTS AND METHODS: Sixty-four previously untreated adults with chronic-phase CML who were enrolled onto CALGB 8761, a molecular-monitoring companion study to a treatment study for adults with chronic-phase CML (CALGB 9013). Treatment consisted of repetitive cycles of interferon alfa and low-dose subcutaneous cytarabine. Blood and marrow Southern blot quantitation of BCR gene rearrangements was compared with marrow cytogenetic analysis before the initiation of treatment and of specified points during therapy. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis was performed to detect residual disease in patients who achieved a complete response by Southern blot or cytogenetic analysis. RESULTS: Quantitative molecular monitoring by Southern blot analysis of blood samples was found to be equivalent to marrow monitoring at all time points. Twelve of 62 (19%) follow-up samples studied by Southern blot analysis had a complete loss of BCR gene rearrangement in matched marrow and blood specimens. Southern blot monitoring of blood samples was also found to be highly correlated to marrow cytogenetic evaluation at all points, although there were four discordant cases in which Southern blot analysis of blood showed no BCR gene rearrangement, yet demonstrated from 12% to 20% Philadelphia chromosome-positive metaphase cells in the marrow. RT-PCR analysis detected residual disease in five of six patients in whom no malignant cells were detected using Southern blot or cytogenetic analyses. CONCLUSION: Quantitative Southern blot analysis of blood samples may be substituted for bone marrow to monitor the response to therapy in CML and results in the need for fewer bone marrow examinations. To avoid overestimating the degree of response, marrow cytogenetic analysis should be performed when patients achieve a complete response by Southern blot monitoring. This approach provides a rational, cost-effective strategy to monitor the effect of treatment of individual patients, as well as to analyze large clinical trials in CML.

Adult↗
PubMed1997

Predictors of time to institutionalization of patients with Alzheimer's disease: the CERAD experience, part XVII.

We studied the time to institutionalization (or death as the first event) in 727 white patients with Alzheimer's disease (AD) enrolled in the Consortium to Establish a Registry for Alzheimer's disease (CERAD). At the time of analysis, 417 patients had been admitted to nursing homes and 32 others had died without previous institutionalization. The major predictors of time to first event were sex, age, marital status (men only), and severity of dementia at entry into the study, as measured by activities of daily living, the Mini-Mental State Examination, and the Clinical Dementia Rating scale. The overall median time from enrollment in the study to first event was 3.1 years. For unmarried men, the median time was significantly less (2.1 years) than for either married men or for married or unmarried women, all of whom had medians greater than 3 years. In an analysis of survival time following institutionalization, we found that men survived a median of 2.1 years, compared with 4.5 years for women. This nationwide study of AD largely confirms earlier studies that reported on smaller numbers of cases from local catchment areas and included patients with various types of dementia.

Aged↗
PubMed1997

Smoking, gender, and survival association with allele loss for the LOH11B lung cancer region on chromosome 11.

We have reported frequent allele loss for the marker HRAS on chromosome 11p in human lung cancer and defined the smallest common region of deletion (designated LOH11B) to approximately 500 kb. Here, we investigated the association of allele loss for LOH11B with epidemiological, pathological, and clinical parameters. Analysis of allele loss was performed using Southern blotting on a cohort of 200 patients with lung cancer, and data were interpreted with the use of a phosphorimager. Results were statistically compared with retrospectively collected variables. LOH11B allele loss was significantly associated with cigarette consumption (P = 0.009), gender (P = 0.02), and survival (P = 0.04). None of the nonsmokers had allele loss as compared with 28% of the patients with low and 43% with high cigarette consumption. Allele loss was more frequent in men (43%) than in women (11%). The median survival of patients without allele loss was 42 months compared with 25 months for patients with allele loss. These results suggest that the LOH11B region contains a gene responsible for a more malignant phenotype independent of the metastatic potential of lung cancer. They also suggest that alterations in this gene are associated with cigarette consumption and are more frequent in men than in women.

Adult↗
PubMed1996

The effect of trinitrobenzene sulfonic acid (TNB) on colonocyte arachidonic acid metabolism.

In previous studies we found that luminal perfusion of the isolated left colon of the rabbit with the hapten, trinitrobenzene, resulted in the production of an acute inflammatory process associated with alterations in eicosanoid metabolism. As the colitis was attenuated by cyclooxygenase inhibitors it is possible that the inflammation was mediated by arachidonic acid metabolites. In the present study it was intended to evaluate the effect of trinitrobenzene on eicosanoid metabolism in transformed human colonic cells by exposing Caco-2++ cells to various doses of trinitrobenzene. Cell injury was evaluated by measuring lactate dehydrogenase levels and cyclooxygenase and lipoxygenase activity was evaluated by measuring prostanoid and leukotriene production. In separate experiments resting and trinitrobenzene stimulated cells were treated with indomethacin and dexamethasone. Trinitrobenzene produced increased prostaglandin E2 and 6-keto prostaglandin F1alpha++ and increased lactate dehydrogenase levels. Leukotriene B4 was significantly increased compared to control values at the highest TNB concentration administered. Indomethacin inhibited the lactate dehydrogenase and prostanoid changes, suggesting that the inflammatory changes produced were mediated by the prostanoids. Dexamethasone administered for 1 hr prior to trinitrobenzene decreased the 6-keto prostaglandin F1alpha but did not alter trinitrobenzene produced changes in lactate dehydrogenase concentrations. Exposure of Caco-2 cells to dexamethasone for 24 hr decreased the trinitrobenzene produced lactate dehydrogenase and eicosanoid changes. The results suggest that trinitrobenzene produces an acute injury to Caco-2 cells that may be mediated by the cyclooxygenase enzymes.

Arachidonic Acid↗
PubMed1996

Measurement of upper extremity orientation by video stereometry system.

In the attempt to gain a broader understanding of the causal relationships behind work-related symptoms of pain in the human shoulder, monitoring of arm position is crucial. Different methods have been used with varying accuracy. A video-based stereometry system, using infra-red light and reflecting markers for motion analysis, has been introduced for measurements in the fields of ergonomics, biomechanics and sports medicine. The purpose of this study is to investigate the sources of error in using this system for posture registration of the upper limb. Measurements are performed on a calibration fixture, on a mechanical model of the upper limb and on a subject with an exoskeleton. Particular, attention is given to inconsistencies and relative errors due to the finite geometrical precision with which the markers are positioned in the calibration fixture and on the studied objects, the limited capability to align the objects relative to the coordinate system of the calibration fixture and the errors connected to angular measurements using protractors etc. It is concluded that the system makes a valuable addition to existing instruments for non-contact posture measurement, and produces position data with an adequate accuracy in normal handling.

Arm↗
PubMed1996

Estimating the validity of the clinical Dementia Rating Scale: the CERAD experience. Consortium to Establish a Registry for Alzheimer's Disease.

The Clinical Dementia Rating (CDR) scale is broadly accepted by clinicians as a staging measure for Alzheimer's disease (AD). Extensive assessment of its validity is, however, lacking. We examined the concurrent and predictive validity of both summary CDR scores (global CDR, Sum of Boxes [sum of scores on the individual components]) and scores on two (Memory and Orientation) of the CDR's six components (the other four components are judgement and problem-solving, community affairs, home and hobbies, personal care) using cross-sectional, longitudinal and survival information on 434 community-resident probable AD patients. Cross-sectionally the Orientation box score correlated substantially with an independent neuropsychology measure of orientation, but the Memory box score correlated more poorly with an independent measure of memory than with any other neuropsychology measure. The relationship of the global CDR score and the Sum of Boxes score to scores on neuropsychology measures was comparable to that of the Orientation and Memory box scores. Longitudinally, Memory box score a year later was predicted equally well by the other box scores (personal care excepted). The individual components were comparable to both summary CDR scores in predicting time to death. The CDR has content and criterion validity. However, since intentionally all components measure aspects of cognitive functioning, they are closely related. Nevertheless, sufficient distinctions remain that assessment in each area is still warranted.

Aged↗
PubMed1996

Global increases in allergic respiratory disease: the possible role of diesel exhaust particles.

OBJECTIVE: Reading this article will enable the readers to recognize and evaluate i e potential relationship between allergic respiratory disease and polyaromatic hydrocarbons as air pollutants from industrial and automotive fuel sources. In this article we review the long-term trends in the prevalence of allergic airway diseases (rhinitis and asthma). We then examine the epidemiologic and other research data relating to the role that hydrocarbon fuel emissions may have had on allergic respiratory disease. DESIGN: Published literature on the relationship between specific air pollutants and trends in allergic respiratory disease were reviewed. Reports of research on pollutant effects on allergic antibody (IgE) were also studied. In both cases, the Melvyl-Medline database since 1975 was used for literature searches. Older references were identified from the bibliographies of relevant articles and books and with the help of the rare books collection at UCLA's Louis M. Darling Biomedical library. RESULTS: Examination of the historical record indicates that allergic rhinitis and allergic asthma have significantly increased in prevalence over the past two centuries. Although the reasons for this increase are not fully elucidated, epidemiologic data suggest that certain pollutants such as those produced from the burning of fossil fuels may have played an important role in the prevalence changes. Also important are studies showing that diesel exhaust, a prototypical fossil fuel, is able to enhance in vitro and in vivo IgE production. CONCLUSION: Increased levels of the compounds resulting from fossil fuel combustion may be partly responsible for the increased prevalence of allergic respiratory disease. If the nature of these compounds and the mechanisms by which they exacerbate allergic disease can be identified, steps can be taken to reduce the production or the impact of these allergy producing compounds.

Humans↗
PubMed1996

Smoking discussions at the child health clinic. A passive, an advisory or a judgemental approach?

Interviews with 15 nurses working in child health care revealed that most of them were very keen not to apportion blame when discussing smoking habits with parents. Thus, half of those interviewed chose a passive approach to counselling, which meant that they were cautious, evasive and tactful so as not to risk alienating or offending parents. Those who were more active tackled the issue of smoking by giving advice and suggesting ways in which the parents could cope with their smoking. A third approach was observed in which some of the nurses were judgemental, which they expressed by moralizing about the smoking habits of the parents. The present study shows that there is a need to develop a patient-centered methodology, whereby smoking can be discussed from the standpoint of the parents, without making them feel guilty.

Adult↗
PubMed1996

The consortium to establish a registry for Alzheimer's disease (CERAD). Part XIV: Demographic and clinical predictors of survival in patients with Alzheimer's disease.

We made follow-up observations on 1,036 Consortium to Establish a Registry for Alzheimer's Disease (CERAD) patients with Alzheimer's disease (AD) enrolled in 21 university medical centers in the United States. Evaluations were scheduled annually for as long as 7 years; at the time of analysis, there were 332 deaths. The median duration of survival from time of entry into CERAD was 5.9 years (95% CI; 5.6 to 6.4 years). Factors independently affecting survival were sex, age, and severity of dementia as measured by the Clinical Dementia Rating scale and the Blessed Scale for activities of daily living. The median survival after entry was 5.7 years for men, compared with 7.2 years for women. For men age 70, 75, and 80 years, median survival times were 6.5, 5.5, and 4.4 years, values notably less than those for the general population. Neither race, education, nor marital status significantly affect survival. This large nationwide study confirms the fact that AD is associated with shorter survival, particularly in men, subjects age 70 or older, patients with greater impairment in daily activities of living, and those with more severe dementia.

Activities of Daily Living↗
PubMed1995

Behavioral laterality in individuals with Gilles de la Tourette's syndrome and basal ganglia alterations: a preliminary report.

This study aims to investigate whether abnormalities in structural basal ganglia asymmetries in Tourette's syndrome (GTS) have functional significance. Eleven adult GTS patients and 11 normal controls who had participated in the previous MRI study where GTS patients lacked the normal left-greater-than-right (L > R) lenticular asymmetry were re-recruited. They were administered a battery of lateralizing neuropsychological tasks believed to require intact basal ganglia function. GTS subjects lacked normal functional asymmetries on these measures, as predicted. The neuropsychological measures also accounted for a significant portion of the variance in the severity of tic symptoms. These findings suggest that GTS subjects who lack normal basal ganglia structural asymmetries also lack normal functional asymmetries on related neuropsychological measures.

Adult↗
PubMed1995

Structure and internal consistency of a shoulder model.

A three-dimensional biomechanical model of the shoulder is developed for force predictions in 46 shoulder structures. The model is directed towards the analysis of static working situations where the load is low or moderate. Arbitrary static arm postures in the natural shoulder range may be considered, as well as different kinds of external loads including different force and moment directions. The model can predict internal forces for the shoulder muscles, for the glenohumeral, the acromioclavicular and the sternoclavicular joint as well as for the coracohumeral ligament. A solution to the statistically indeterminate force system is obtained by minimising an objective function. The default function chosen for this is the sum of the squared muscle stresses, but other objective functions may be used as well. The structure of the model is described and its ingredients discussed. The internal consistency of the model, its structural stability and the compatibility of the elements that go into it, is investigated.

Acromioclavicular Joint↗
PubMed1995

Functional significance of individual variations in callosal area.

We considered the hypothesis that the richness of callosal interhemispheric connections has a role in determining the degree of behavioural laterality and time-sharing ability in dual-task performance. Behavioural laterality as measured by dichotic word listening, line bisection and turning bias tests correlated inversely with the midsagittal cross-sectional area of the corpus callosum, as seen on MRI. The amount of dual task interference was strongly inversely correlated with the callosal area in both within-hemisphere and between-hemispheres conditions. These relationships between normal variations in callosal area, and outcomes on tests both of laterally and time-sharing capacity in normal adults suggest that the corpus callosum assumes a cross-excitatory role when subjects perform these tasks.

Adult↗
PubMed1995

Placement of umbilical venous catheters with use of bedside real-time ultrasonography.

Real-time ultrasonography was used to assess the position of umbilical venous catheters tips in 79 newborn infants (birth weight range, 400 to 4200 gm). The position of the umbilical venous catheters determined by ultrasonography was compared with the projection of the catheter tip on the closest vertebral body shown on a standard chest radiograph. Of the catheters initially placed with radiographic guidance, 56% were repositioned because of unsatisfactory location. Ultrasonography is more precise than radiography because it allows direct visualization of the catheter tips in relation to internal vascular structures. When ultrasonography is unavailable, placement at the ninth thoracic vertebral body ensures safe positioning.

Catheterization↗
PubMed1995

Voluntary redistribution of muscle activity in human shoulder muscles.

Four shoulder muscles (the supraspinatus, the infraspinatus, the anterior and middle portion of the deltoid, and the descending part of the trapezius) were examined with electromyography in abducted arm positions. By using feedback techniques, we found that the subjects could reduce the EMG activity voluntarily by 22-47% in the trapezius muscle while keeping different static postures. This was not true for any other muscle investigated. When the trapezius activity was reduced there was a tendency towards an increase of EMG activity in some other shoulder muscles, particularly the infraspinatus. The findings may be related to relaxation from an initial overstabilization of the shoulder, or redistribution of load among synergists. It is suggested that the possibility of reducing trapezius activity may be of ergonomic significance. It is also noted that EMG trapezius activity may not serve as a universal descriptor of total muscular load in the shoulder.

Adult↗