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Biomedical subjects

C Holmes

Publications and source records attributed to C Holmes.

At least 145 records · Page 8Linked to original sources
PubMed1976

Detection of human tumor-associated antigens by the leukocyte migration in agarose assay.

Twenty-three of 36 (64%) lung cancer patients, 19 of 36 (54%) melanoma patients and 18 of 27 (66%) sarcoma patients tested in the leukocyte migration in agarose assay against soluble extracts of histologically similar tumors showed significant inhibition of leukocyte migration. Reactivity to extracts of dissimilar tumors was low. Sera of only 1/13 (7%) lung cancer patients, 2/19 (10%) melanoma patients and 7/21 (33%) sarcoma patients were inhibited by extracts of histologically dissimilar tumors. Only 7-9% of cancer patients reacted to paired extracts of normal tissue from the tumor donors. An average of 13% of sera from normal controls reacted to tumor extracts. Stage of disease and mode of therapy appeared to have little effect on overall reactivity in this assay, although the number of patients within the various categories was small for purposes of statistical analysis. The leukocyte migration in agarose assay shows a sensitivity and specificity to tumor-associated antigens comparable to that of the older capillary tube method in general use and may facilitate performance of migration inhibition. This assay may not be useful as a prognostic test due to the lack ofcorrelation with stage of disease and treatment modality. However, its high specificity and economical use of tumor antigen suggest applications in tumor antigen purification. The use of soluble tumor antigen preparations may make it possible to purify these antigens further to increase specificity and reactivity.

Antigens, Neoplasm↗
PubMed1975

Causal attributions as a function of locus of control, initial confidence, and performance outcomes.

Causal attributions and body movements indicative of tension were recorded while subjects completed an anagrams task that was more extensive than most similar tasks used in attribution studies. Nine trials each containing 10 anagrams were presented such that most subjects succeeded on three sets of relatively simple anagrams, failed on three sets of difficult anagrams, and either succeeded or failed on three sets of intermediately difficult anagrams. Attributions and body movements were predicted by a combination of locus of control, initial confidence, and type of outcome. High-confident internals attributed responsibility for outcomes to themselves more than did low-confident externals, and this difference was most prominent when subjects failed. Tension-indicating body movements were also less common among the former than the latter subjects and were in greater evidence with failure than with success. The data indicate that there is consistency between locus of control and causal attributions obtained during performances. The data also correspond to the findings on helplessness in which aversive agents prove to be more deleterious when individuals perceive themselves as unable to alter their negative circumstances.

Achievement↗
PubMedDate not supplied

Recovery from early cortical lesions in rats. III. Neonatal removal of posterior parietal cortex has greater behavioral and anatomical effects than similar removals in adulthood.

The behavioral, anatomical, and electrophysiological effects of posterior parietal cortex lesions (Krieg's area 7) were compared in rats with removals at 1, 5, or 10 days of age or in adulthood. Behaviorally, the animals were administered several tests including grooming, beam walking, swimming, the Morris water task and a radial arm maze. Lesions at 10 days of age permitted behavioral sparing on most behavioral tasks, whereas lesions at 1 or 5 days of age allowed little sparing and even produced larger deficits than observed in adult operates on some tasks. Anatomical measures showed a direct relationship between cortical thickness and age of lesion: the earlier the lesion, the thinner the cortex. An analysis of postsurgical changes in cortical thickness showed only a small reduction in cortical thickness shortly after the lesions, with the major reduction occurring during adolescence. Electrophysiological recordings of cortical activity showed that rats with 1-day lesions had abnormal neocortical atropine-resistant activity and had an increased incidence of seizures. The results suggest that the neocortex of the rat may be particularly sensitive to perinatal injury.

Aging↗
PubMedDate not supplied

Putting drug use in context. Life-lines of African American women who smoke crack.

The purpose of this exploratory study was to describe a group of African American women who smoke crack. Using aggregate data from 208 interviews with women crack smokers, we randomly selected 25 women's interview data to create the 25 life-lines. These life-lines were developed in a similar manner to the time-line analysis described by Fullilove and her colleagues (1992); we focused on events that are either extraordinarily disturbing (e.g., rape, incest, death of a child, etc.), events that are usual but often stressful (e.g., birth of a child, death of a parent, etc.), and on periods of drug use. We chose this method of analysis so as to highlight the context in which many women come to use crack cocaine. The life-lines provided a retrospective (but time-ordered) perspective and in several ways provided preliminary support for a stress-diathesis perspective.

Adult↗
PubMedDate not supplied

A four-dimensional probabilistic atlas of the human brain.

The authors describe the development of a four-dimensional atlas and reference system that includes both macroscopic and microscopic information on structure and function of the human brain in persons between the ages of 18 and 90 years. Given the presumed large but previously unquantified degree of structural and functional variance among normal persons in the human population, the basis for this atlas and reference system is probabilistic. Through the efforts of the International Consortium for Brain Mapping (ICBM), 7,000 subjects will be included in the initial phase of database and atlas development. For each subject, detailed demographic, clinical, behavioral, and imaging information is being collected. In addition, 5,800 subjects will contribute DNA for the purpose of determining genotype- phenotype-behavioral correlations. The process of developing the strategies, algorithms, data collection methods, validation approaches, database structures, and distribution of results is described in this report. Examples of applications of the approach are described for the normal brain in both adults and children as well as in patients with schizophrenia. This project should provide new insights into the relationship between microscopic and macroscopic structure and function in the human brain and should have important implications in basic neuroscience, clinical diagnostics, and cerebral disorders.

Adolescent↗
PubMedDate not supplied

One year follow-up of parkinsonism in dementia with Lewy bodies.

The progression of parkinsonism over 1 year was evaluated in a prospective cohort of patients (n = 338), suffering from dementia with Lewy bodies (DLB), Alzheimer's disease (AD) or vascular dementia (VaD). Parkinsonism was assessed using the modified Unified Parkinson's Disease Rating Scale. Significant parkinsonism was significantly commoner in DLB sufferers (71%) than amongst patients with AD (7%) or VaD (10%). DLB patients with established parkinsonism had an annual increase in severity of 9%, but progression was more rapid (49% in 1 year) in patients with early parkinsonism. Parkinsonism was frequent at all severities in DLB patients, but usually only present in other dementias when MMSE <10.

Aged↗
PubMedDate not supplied

Preliminary neurochemical findings in non-Alzheimer dementia due to lobar atrophy.

Non-Alzheimer's dementia due to lobar atrophy had choline acetyltransferase activities comparable with control rather than Alzheimer's disease values, based on 3 autopsy proven cases on Pick's disease and biopsies from 3 examples of dementia of frontal lobe type. Muscarinic cholinergic receptors were relatively spared only in Alzheimer's disease. Serotonin receptors were markedly reduced (based on Pick cases) whereas measures that reflected presynaptic serotonergic activity were either not affected or increased. Cerebrospinal fluid and brain tissue measurements suggested that inhibitory interneurones and dopamine release were relatively spared. There was no in vitro evidence of hypometabolism.

Atrophy↗
PubMedDate not supplied

Metabolic fate of the sympathoneural imaging agent 6-[18F]fluorodopamine in humans.

We examined the metabolism of 6-[18F]fluorodopamine, by assaying arterial plasma concentrations of radioactivity, 6-[18F]fluorodopamine, and 6-[18F]fluorodopamine metabolites in untreated subjects or subjects given desipramine to block neuronal uptake of catecholamines or tyramine to displace vesicular amines. After the 3-min 6-[18F]fluorodopamine infusion, plasma 6-[18F]fluorodopamine levels declined precipitously, total radioactivity declining slowly. After 30 min, the main identified metabolite was 6-[18F]fluorodopamine-sulfate. Desipramine attenuated the rapid increase in plasma 6-[18F]fluorodihydroxyphenylacetic acid levels, and tyramine briefly increased 6-[18F]fluorodopamine levels. Neither drug affected 6-[18F]fluorodopamine-sulfate levels. The results indicate that soon after 6-[18F]fluorodopamine infusion, plasma radioactivity corresponds mainly to 6-[18F]fluorodopamine metabolites; that sympathetic nerves rapidly remove 6-[18F]fluorodopamine, which then undergoes oxidative deamination in the neuronal cytoplasm and sequestration in sympathetic vesicles; and that sulfoconjugation of [18F]fluorodopamine occurs extraneuronally.

Administration, Oral↗
PubMedDate not supplied

Comparison of liquid chromatography/mass spectrometry, ELISA, and phosphatase assay for the determination of microcystins in blue-green algae products.

More than 100 samples of blue-green algae products (consisting of Aphanizomenon, Spirulina, and unidentified blue-green algae) in the form of pills, capsules, and powders were collected from retail outlets from across Canada. The samples were extracted with 75% methanol in water and centrifuged to remove solids. Aliquots of the extracts along with spiked blank sample extracts were sent to each participating laboratory and independently analyzed for microcystins by enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition assay, and by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after sample cleanup using C18 solid-phase extraction. The results obtained by ELISA and LC-MS/MS agreed very well over a concentration range of about 0.5-35 microg/g. The colorimetric phosphatase results generally agreed with the other 2 methods. While the 2 biochemical assays measured total microcystin content compared with a standard of microcystin LR, the LC-MS/MS method measured specific microcystins (LA, LR, RR, YR) using external standards of these for identification and quantitation. Microcystin LR was found in all positive samples by LC-MS/MS. Microcystin LA was the only other microcystin found in the samples analyzed. These 2 microcystins represent essentially all the microcystins that were present in the extracts. Otherwise, the LC-MS/MS results would have been significantly lower than the results of the biochemical assays had other unknown microcystins been present.

Chromatography, Liquid↗
PubMedDate not supplied

Biofilm formation on peritoneal catheters does not require the presence of infection.

The presence of biofilm is thought to accompany infection or colonization of chronic peritoneal dialysis (PD) catheters, and to be an important pathogenetic factor in the recurrence or persistence of peritonitis. In the current study, the characteristics of identifiable biofilm associated with the PD catheter were studied using scanning and transmission electron microscopy in six consecutive cases requiring catheter removal for a variety of indications. Biofilm characteristics in each case were rated in blinded fashion by three independent observers, and findings were then correlated with the clinical histories and microbiologic findings. Surprisingly, two of the three cases with the most severe biofilm formation occurred in patients with no history or microbiologic findings of recent infection, and the positive findings of leukocytes, macrophages, fibrillar matrix, and other structures on these catheters did not correlate with detectable infection. In addition, extracellular spherical lipoid structures and intracellular lipoid vacuoles in mesothelial-like cells were prominent in four of six cases, did not correspond to the presence of infection, and suggested possible mesothelialization of the catheter. The findings of this study do not necessarily controvert the microbial origin of some components of the biofilm, or the possible role of biofilm in some cases of persisting peritoneal infection. However, it is clear that many important components of the biofilm arise, not from microorganisms, but rather from host origin in the absence of detectable infection. Moreover, such "endogenous" biofilm production can result in extensive accumulation of catheter-associated matrix.

Adult↗