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Biomedical subjects

M Champion

Publications and source records attributed to M Champion.

At least 19 recordsLinked to original sources
PubMed2000

Inducible resistance to oxidant stress in the protozoan Leishmania chagasi.

Leishmania sp. protozoa are introduced into a mammalian skin by a sandfly vector, whereupon they encounter increased temperature and toxic oxidants generated during phagocytosis. We studied the effects of 37 degrees C "heat shock" or sublethal menadione, which generates superoxide and hydrogen peroxide, on Leishmania chagasi virulence. Both heat and menadione caused parasites to become more resistant to H(2)O(2)-mediated toxicity. Peroxide resistance was also induced as promastigotes developed in culture from logarithmic to their virulent stationary phase form. Peroxide resistance was not associated with an increase in reduced thiols (trypanothione and glutathione) or increased activity of ornithine decarboxylase, which is rate-limiting in trypanothione synthesis. Membrane lipophosphoglycan increased in size as parasites developed to stationary phase but not after environmental exposures. Instead, parasites underwent a heat shock response upon exposure to heat or sublethal menadione, detected by increased levels of HSP70. Transfection of promastigotes with L. chagasi HSP70 caused a heat-inducible increase in resistance to peroxide, implying it is involved in antioxidant defense. We conclude that leishmania have redundant mechanisms for resisting toxic oxidants. Some are induced during developmental change and others are induced in response to environmental stress.

Animals↗
PubMed2000

Genotypes and phenotypes of patients in the UK with carbohydrate-deficient glycoprotein syndrome type 1.

18 UK patients (14 families) have been diagnosed with the carbohydrate-deficient glycoprotein syndrome (CDGS), type 1, on the basis of their clinical symptoms and/or abnormal electrophoretic patterns of serum transferrin. Eleven out of the 16 infants died before the age of 2 years. Patients from 12 families had a typical type 1 transferrin profile but one had a variant profile and another, who had many of the clinical features of CDGS type 1, had a normal profile. Eleven of the patients (10 families) with the typical type 1 profile had a deficiency of phosphomannomutase (PMM), (CDGS type 1a) but there was no correlation between residual enzyme activity and severity of disease. All these patients were compound heterozygotes for mutations in the phosphomannomutase (PMM2) gene, with 7 out of the 10 families having the common R141H mutation. Eight different mutations were found, including three novel ones. There was no correlation between genotype and phenotype, although siblings had similar phenotypes. Three patients, including the one with the normal transferrin profile, did not have a deficiency of phosphomannomutase or phosphomannose isomerase (CDGS 1b).

Cells, Cultured↗
PubMed2000

Solubility, absorption, and anti-Helicobacter pylori activity of bismuth subnitrate and colloidal bismuth subcitrate: In vitro data Do not predict In vivo efficacy.

OBJECTIVES: The aim of this study was to compare the dissolution, bioavailability, and anti-Helicobacter pylori activity of bismuth subnitrate and colloidal bismuth subcitrate. This could, first, provide insights into the mechanism of action of bismuth and, second, help to develop optimal therapeutic strategies. METHODS: Solubility and aquated size of bismuth species were determined in human gastric juice, while absorption into blood and urinary excretion of bismuth was determined in volunteers. Activity against H. pylori was determined in vitro in the presence and absence of antibiotics, while H. pylori eradication was compared in vivo. RESULTS: Bismuth from colloidal bismuth subcitrate was at least 10% soluble and ultrafilterable and was absorbed in volunteers (>0.5%), whereas that from bismuth subnitrate was insoluble and not absorbed (<0.01%). Colloidal bismuth subcitrate was active against H. pylori (mean inhibitory concentration, </=12.5 microg/ml), while bismuth subnitrate was inactive (>400 microg/ml); neither was synergistic with antibiotics. With in vivo triple therapy, bismuth subnitrate was as effective as colloidal bismuth subcitrate in eradicating H. pylori (74% and 70% eradicated, respectively). CONCLUSIONS: Colloidal bismuth subcitrate, unlike bismuth subnitrate, is partially soluble, absorbed in humans, and directly toxic to H. pylori in vitro. Surprisingly, however, these preparations had similar efficacy in vivo against H. pylori within triple therapy, suggesting that bismuth compounds may also exhibit indirect antimicrobial effects. We propose that this is an effect on the gastric mucus layer. Nonabsorbable bismuth compounds should be preferentially considered in bismuth-based therapies against H. pylori, as they would minimize toxicity while maintaining efficacy.

Anti-Bacterial Agents↗
PubMed2000

[Magnetic resonance angiography of stents].

PURPOSE: To understand the behavior of stents during contrast-enhanced magnetic resonance angiography (MRA). MATERIALS AND METHODS: Seven different types of stents are explored in vitro with spin echo (SE) T2 sequence and MRA sequences using classification of the intra-prothesis signal. Six patients with 11 different proximal stents are studied by Gadolinium enhanced MRA with the same classification. RESULTS: Stent material is not the only determinant of behavior. In this way, one stainless steel stent produced less intra-luminal hyposignal than a nitinol device. Nevertheless, only a nitinol stent did not alter the intra-prothesis signal and allowed an appreciation of patency, despite a decrease of diameter and presence of edge artifacts. CONCLUSION: Even if stent compatibility is well known with MRI, even with Gadolinium, cannot be used alone to depict stenosis or diameter reduction. Even patency based on the presence of a constant signal, cannot be confirmed routinely with confidence: indeed, only a single stent does not modify intra-arterial signal.

Aged↗
PubMed1999

[Secrecy in children with HIV infection].

The secrecy surrounding the disease of parents and children infected with HIV leads to psychic and affective isolation and difficulties of communication within the family. Psychological management may possibly help to resolve the problem of secrecy between parents and children. We analyzed the organization and dynamics of the secret surrounding children contaminated by their mothers. The analysis was prospective and was based on semi-directive interviews and drawings. We followed up, over a period of two years, ten children (mean age: 4 years, range: 4 months to 12 years) with different ethnic and socio economic backgrounds. In each family, the child was the target of the secret, the pediatrician the guardian, and the mother (or her substitute) the keeper. The organization of the secret around the other potential guardians varied from one family to another. Two modes of intra-family communication were observed: the secret (reserved for the youngest children) and the tacit. One child suffered from a disorder related to the secret, the others had depressive and reactional symptoms. At the end of the study, the manner of approaching, and especially dealing with, the question of the secret had changed appreciably in each family: disclosure to the family circle (three cases), passage of the child from the secret to the tacit (two cases), and easier questioning of the pediatrician in all of the cases. Nonetheless, in no case had the secret been completely lifted for the child. Four children asked to continue psychological management. The changes in the dynamics of the secret and the appeasement observed in the families suggest that psychotherapeutic aid should be offered to families where a child has been contaminated with HIV by the mother.

Attitude to Health↗
PubMed1997

Health economics of gastroesophageal reflux disease.

The present study provides an overview of the current state of health economics studies of gastroesophageal reflux disease (GERD). It indicates the strengths and weaknesses of individual studies, and the state of health economics analysis in general as they apply to GERD. Specifically, this study adopts a pharmacoeconomic perspective, which is a subsection of health economics analytical methods, to provide a comparative analysis of alternative courses of action based on cost and consequence. The pharmacoeconomic outlook is most effective when it considers a comprehensive societal perspective, with special consideration given to other relevant viewpoints, such as the payer, the primary provider and, most important, the patient. Pharmacoeconomics provides several specific analytical techniques for GERD-related health economics analysis. The Canadian Association of Gastroenterology consensus conference on GERD in 1996 thought that a cost effective analysis was the most appropriate technique to assess the pharmacoeconomics of GERD. Six previous studies on GERD health economics have been performed comparing omeprazole with H2 receptor antagonists. These studies vary in cost data collected and in analytical techniques. In general, the existing outcome measurements of these previous health economics studies are not ideal. Namely, they combine various GERD grades, use randomized controls, are endoscopically based, assess pharmaceutical therapy only and are short term. More appropriate health economic trials in GERD, which focus on GERD management strategies and therapeutic treatment of GERD, need to be designed and conducted. These economic assessments, however, should not replace detailed thinking, careful observation, good judgement and common sense.

Canada↗
PubMed1996

Physicians' documentation of sexual abuse of children.

OBJECTIVES: To assess the quality of documentation by physicians in their evaluations for sexual abuse of children and to define factors that affect documentation. DESIGN: Cross-sectional survey and blinded chart review. SETTING: A statewide program for child abuse evaluations. PARTICIPANTS: Physicians (n = 145) who performed evaluations during fiscal year 1992-1993 were surveyed. Up to five randomly chosen medical records (n = 548), obtained from each eligible physician, were reviewed. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: A survey of physicians who participated in the statewide program was made in summer 1993, with 78% participation. Knowledge scores were derived from the survey based on a comparison with the responses of a panel of five experts. Charts that were obtained from eligible physicians were assessed by two blinded reviewers. Documentation of the history and physical examination was evaluated as good or excellent by 30% and 23% of the physicians, respectively. Factors that were positively associated with better documentation of the history included a more structured format for the record, continuing medical education courses on sexual abuse of children, female gender, and a history of disclosure (P < .005 for all). Factors that were related to good documentation of the physical examination included structured records, continuing medical education courses, female gender, and knowledge scores. Factors that were not related to knowledge or documentation included the number of evaluations performed, practice group size or location, age of the physician, and a physician's reading of journal articles about sexual abuse of children. CONCLUSION: Quality of evaluations for sexual abuse of children may be improved by the use of structured records and participation in continuing medical education courses with regard to sexual abuse of children.

Adult↗
PubMed1996

Different behavioral effects of haloperidol, clozapine and thioridazine in a concurrent lever pressing and feeding procedure.

Rats were tested using a lever pressing/feeding procedure in which a preferred food (Bioserve pellets) was available by pressing a lever on a fixed ratio 5 schedule, but a less preferred food (lab chow) was also available concurrently in the operant chamber. The effects of repeated (14 day) injections of haloperidol, clozapine and thioridazine were compared. Haloperidol (0.05-0.15 mg/kg) significantly reduced lever pressing and increased chow intake throughout the drug treatment period. Injections of clozapine (2.0-6.0 mg/kg) suppressed lever pressing but failed to produce substantial increases in chow intake. In the haloperidol experiment there was a significant inverse correlation between lever pressing and chow intake, but in the clozapine experiment there was not. Regression analysis indicated that rats treated with the high dose of clozapine showed some tolerance to the suppression of lever pressing. Tests of sedation also were conducted before and after the instrumental behavior sessions. Haloperidol produced little or no sedative effect in the dose range tested. Clozapine produced substantial sedation during the first 10 days of administration, but this effect, like the suppression of lever pressing, showed signs of tolerance. Thioridazine (3.0-9.0 mg/kg) produced some effects that resembled haloperidol, and other effects, including sedation, that resembled clozapine. These studies indicate that haloperidol suppresses lever pressing for food at low doses that do not produce severe motivational or sedative effects that disrupt food intake. In contrast, it appears as though the suppression of lever pressing produced by clozapine stems from a sedative effect that also serves to set limits on chow intake. These results indicate that haloperidol and clozapine suppress lever pressing through different mechanisms.

Animals↗
PubMed1996

[Peritoneal mesothelioma. Contribution of MRI. Apropos of a case].

Peritoneal invasion by a malignant mesothelioma is less frequently encountered than pleural localization. We report a case of a double pleural and peritoneal localization. CT and MR may be suggestive, especially when pulmonary asbestosis is associated, but pathology (fine needle aspiration or surgical biopsy) is necessary to assess the diagnosis. When possible surgery is performed, with or without associated radiotherapy. Prognosis is nevertheless very poor.

Humans↗
PubMed1996

[Malignant adrenocortical carcinoma with atypical aspect. Value of tomodensitometry and magnetic resonance imaging. Apropos of a case].

A case of large and non-functioning malignant adrenal tumor is reported. It was discovered incidentally during a check-up ordered because of sciatic pain caused by an osteolytic lesion of the sacrum. This huge abdominal tumor was suspected to be an adrenal tumor one the basis of the CT and MR findings. Histological analysis of percutaneous biopsies were unable to define the site and etiology of these two masses. Only histo-pathological examination of the surgical specimen allowed the diagnosis of adrenal cortical carcinoma.

Adrenal Cortex Neoplasms↗
PubMed1995

Pholedrine: a substitute for hydroxyamphetamine as a diagnostic eyedrop test in Horner's syndrome.

Mydriatic responses to eyedrops containing the indirect acting sympathomimetic amines tyramine, hydroxyamphetamine, and pholedrine have been compared in 10 healthy subjects. Pholedrine, the n-methyl derivative of hydroxyamphetamine, at a concentration of 1% had effects similar to those produced by 0.5% hydroxyamphetamine itself. Pretreatment with topical guanethidine attenuated its responses and in 13 patients with unilateral Horner's syndrome it distinguished clearly those five patients who had preganglionic from the eight with postganglionic lesions. It is concluded that 1% pholedrine may be substituted for 0.5% hydroxyamphetamine, which is no longer available, as a diagnostic agent for use in Horner's syndrome.

Adolescent↗
PubMed1994

[Spontaneous rupture of the rectum. Contribution of CT scan. Apropos of a case].

We report a case of spontaneous rupture of the rectosigmoid junction demonstrated by surgical and histological examination. This rare complication of chronic constipation is difficult to confirm except in the case of the typical clinical presentation with lower abdominal pain after defaecation and evisceration of small intestine loops through the anus. No radiological procedure is usually performed except for plain abdominal radiograph, to demonstrate inconstant (retro)peritoneal emphysema. CT scan could detect free air outside of the rectosigmoid lumen, suggesting parietal rupture and allowing appropriate surgical treatment on the lower digestive tract.

Aged↗
PubMed1994

[Gallbladder duplication. Apropos of a case of echographic finding].

Duplication of the gallbladder is a rare congenital anomaly, which must be depicted by sonography, although false positive and negative diagnosis could still be made. Usually abdominal sonography allows duplication diagnosis as reported in our case and a cholecystography may be performed to determine the type of the anomaly. When a surgical procedure needs to be performed, especially in case of coelioscopic technique, surgeon needs to know the exact anatomic type of the anomaly and the number of gallbladders he will find.

Adult↗
PubMed1993

[Intrarenal migration of two fractured struts of a vena cava filter].

Filter complications are quite common. The most frequent are distal or proximal migration, angulation, vena cava thrombosis or perforation. We report one case of filter struts fracture and their migration in the right kidney. This complication could require a surgical procedure and demonstrates the importance of filter follow-up with regular abdominal plain X-rays and possibly CT scan and/or cavography.

Aged↗
PubMed1991

[Thoracic extramedullary hematopoiesis. Apropos of a case].

Extramedullary haematopoiesis is a compensatory response of bone marrow to abnormal haematopoietic tissue formation: the commonest etiology is thalassemia (generally intermedia). The thorax is a rare site and the posterior mediastinum is usually involved. CT scan completes standard chest radiology and allows fine needle aspiration to provide adequate cytologic material for the diagnosis of extramedullary haematopoiesis, especially when an intercurrent pathology is present and could involve paravertebral areas. Thoracotomy may be necessary in rare cases of complications.

Adult↗