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Biomedical subjects

A Chapman

Publications and source records attributed to A Chapman.

At least 109 records · Page 6Linked to original sources
PubMed1986

Immunity to Haemophilus influenzae type b in young adults: correlation of bactericidal and opsonizing activity of serum with antibody to polyribosylribitol phosphate and lipooligosaccharide before and after vaccination.

Naturally acquired humoral immunity is thought to protect adults against serious infections due to Haemophilus influenzae type b (Hib). Antibody to the polyribosylribitol phosphate (PRP) capsule is generally considered protective; antibody to lipooligosaccharide (LOS) or outer membrane protein (OMP) may also play a role. Serum from 23 of 50 healthy young adults had no bactericidal effect (BE) against Hib yet opsonized these organisms for approximately 30% uptake by polymorphonuclear leukocytes. The degree of bactericidal and opsonizing activity in serum from the other 27 subjects generally correlated with the level of antibody to PRP but not to LOS or OMP. However, serum from some individuals had levels of antibody to PRP as high as 4.9 micrograms/ml without BE, and seven of 27 subjects with BE had antibody levels of less than 1 microgram/ml. After vaccination with 20 micrograms of conjugated PRP, the level of antibody to PRP was greater than 5 micrograms/ml in all 50 subjects. BE appeared in 22 of those who originally lacked it, and opsonization increased to approximately 50%.

Adult↗
PubMed1986

[Familial IgG kappa myeloma in a mother and her daughter. Review of the literature].

The case of a multiple myeloma secreting IgG kappa in both mother and daughter is reported and discussed in the light of previous reports of familial myeloma and myeloma occurring in spouses. In March 1981, the 60-year-old daughter complained of fatigue leading to the discovery of anemia. The diagnosis of myeloma was based on the association of a monoclonal IgG kappa (57.5 g/l) with low serum levels of IgM and IgA and of an increase (38%) in bone marrow plasma cells. She was treated by chemotherapy and by radiotherapy on bone lesions which appeared during the course of treatment. She died in June 1983. In October 1984, the 84-year-old mother was also found to have anemia. The diagnosis of myeloma was based on the association of a monoclonal IgG kappa (24.5 g/l) with low serum levels of IgM and IgA, 0.6 g/l of Bence-Jones protein in urine, an increase (12%) of atypical plasma cells, and of multiple lytic lesions on X-ray. Familial myeloma has been exceptionally reported. We have found only one case in mother and daughter where the myeloma protein was respectively IgA and IgG. The light chain isotype was not determined. Cases of myeloma occurring in spouses have equally been rarely reported in the medical literature. Genetic transmission of chromosomal determinants for myeloma or a type of response to environmental factors have been suspected as well as environmental determinants for myeloma. Genetically abnormal regulation of immunoglobulin synthesis is another possibility.

Adult↗
PubMed1985

13C-NMR reveals glycerol as an unexpected major metabolite of the protozoan parasite Trichomonas vaginalis.

13C-NMR has been used to study the kinetics of the formation of metabolites from [1-13C]glucose in intact cells of Trichomonas vaginalis during anaerobic incubation. As well as the expected metabolites lactate and acetate, this technique revealed glycerol as an additional major product, present in amounts equimolar with acetate. The formation of glycerol is readily explained in terms of the need to maintain redox balance. This protozoan now joins the small group of organisms which are known to produce glycerol as a result of normal metabolic activities.

Acetates↗
PubMed1985

Synthesis of the major oligosaccharide components of murine haemangioendothelioma cells.

Murine haemangioendothelioma cells in culture synthesize lactosaminoglycan-type glycoproteins which are found both associated with cells and secreted into the culture medium. Pronase-derived glycopeptides, prepared from the [3H]glucosamine-labeled glycoproteins that were secreted into the culture medium were found to contain about 10% of the labeled products as large size (Mr greater than 5000) 3H-labeled glycopeptides. In contrast, 40% of the cellular 3H-glycopeptides were found to be of this large size class of glycopeptides. These large size glycopeptides did not bind to Con A-Sepharose but did bind to Datura stramonium-agarose, from which they were eluted with chitobiose. The glycopeptides which did not bind to Datura-lectin were sulfated complex-type oligosaccharides which were not degraded by endo-beta-galactosidase. The glycopeptides which bound to Datura-lectin were degraded by endo-beta-galactosidase (or keratanase) to yield Gal----GlcNAc----Gal and glycopeptides, which were resistant to further endo-beta-galactosidase digestion and which no longer bound to Datura lectin-agarose. A major [3H]glucosamine-labelled glycoprotein (Mr approx. 75000) was found to be susceptible to endo-beta-galactosidase degradation and is probably the major cellular constituent having lactosaminoglycan-type side chains in these cells. An in vitro assay to measure leucocyte-haemangioendothelioma interactions indicated that treatment of haemangioendothelioma cells with endo-beta-galactosidase reduced leucocyte binding to these cells by 80%.

Amino Sugars↗
PubMed1985

Phagocytosis and killing of common bacterial pathogens of the lung by human alveolar macrophages.

To investigate factors that determine susceptibility of the lungs to infection with common respiratory pathogens, we studied phagocytosis and killing of nontypable Haemophilus influenzae, H. influenzae type b, Streptococcus pneumoniae types III, VI, and XIV, an unencapsulated variant of S. pneumoniae type III, and Staphylococcus aureus Cowan I, by using human alveolar macrophages obtained by bronchoalveolar lavage of healthy nonsmokers. After opsonization with 10% pooled human serum, mean uptake (+/- standard deviation) of nontypable H. influenzae (67.5% +/- 15.0%), unencapsulated S. pneumoniae type III (71.2% +/- 4.8%) and S. aureus (79.1% +/- 10.2%) was significantly greater (P less than .01) than that of H. influenzae type b (40.1% +/- 15.0%), and S. pneumoniae types III (4.4% +/- 3.1%), VI (11.8% +/- 9.6%), or XIV (8.7% +/- 7.0%). Nontypable H. influenzae was ingested after opsonization with much less pooled human serum than was H. influenzae type b, and uptake of encapsulated S. pneumoniae was not enhanced by as much as 80% pooled human serum. Intracellular killing of unencapsulated S. pneumoniae type III and nontypable H. influenzae was rapid and complete and corresponded to the degree of phagocytosis, but despite a high uptake, S. aureus were killed slowly and incompletely. The virulence of S. pneumoniae and H. influenzae as lung pathogens is thus determined jointly by encapsulation and the inadequate opsonizing effect of normal human serum, whereas that of S. aureus may be related to the organism's relative resistance to intracellular killing by alveolar macrophages.

Antibodies, Bacterial↗
PubMed1985

Energy-dispersive X-ray microanalysis of membrane-associated inclusions in hydrogenosomes isolated from Trichomonas vaginalis.

Energy-dispersive X-ray microprobe analysis of electron-dense inclusions in hydrogenosomes isolated from the aerotolerant anaerobic protozoal human parasite Trichomonas vaginalis, Bushby strain, indicated the presence of high levels of Mg, P and Ca. This suggested that divalent cation (e.g. Ca2+ or Mg2+) accumulation by hydrogenosomes may be important in the regulation of intracellular ion concentrations.

Calcium↗
PubMed1985

The generation of metronidazole radicals in hydrogenosomes isolated from Trichomonas vaginalis.

The nitro radical-anion of the anti-trichomonal drug metronidazole has been detected by electron spin resonance spectrometry under anaerobic conditions in suspensions of intact hydrogenosomes isolated from the parasitic protozoon Trichomonas vaginalis. Metronidazole reduction was driven by pyruvate, but progressive damage to the radical generating system was observed. Quenching of signals due to metronidazole radicals by chromium oxalate suggests that the radicals generated within the organelle can cross the hydrogenosomal membrane into the external medium. Even if a similar process of radical migration occurs in vivo, it seems likely that intrahydrogenosomal damage may explain drug action.

Electron Spin Resonance Spectroscopy↗
PubMed1985

Rectal biopsy as a cause of rectal ulceration.

We report three patients in whom the performance of a rectal biopsy produced an ulcer that was found during a subsequent examination (two at double-contrast barium enema examinations and one at colonoscopy). In each case, the iatrogenic ulcers presented an unusual appearance and resulted in the performance of inappropriate follow-up studies.

Adolescent↗
PubMed1985

Pacemaker associated infection due to a corynebacterium species.

Pacemaker associated infection (PAI) is a rare but often serious complication of permanent or temporary transvenous cardiac pacemakers. The major risk factor is recent or multiple pacemaker manipulations or surgical procedures. A PAI can occur at the time of insertion, from contiguous spread to the access site, or from transient bacteremia. We report a case of PAI of a retained pacemaker electrode from which a Corynebacterium species was isolated. Multiple preoperative cultures were sterile, but bacteria were isolated from tissue removed at surgery, and were seen around the wire deep inside a thrombus. The importance of cultures and special stains (including electron microscopy) of surgical materials is stressed, especially when dealing with microorganisms of ordinarily low virulence, or those that are commonly considered laboratory contaminants.

Journal Article↗
PubMed1985

[Hypovolemic shock caused by increased capillary permeability associated with monoclonal gammopathy. New case and review of the literature].

The authors report another case of hypovolaemic shock due to increased capillary permeability and review previous reports in the medical literature. It is a rare condition with all patients presenting hypovolaemic shock of sudden onset with varying degrees of hypoproteinaemia and increased haematocrit. A monoclonal globulin peak is usually observed on serum electrophoresis during and between episodes of shock. The pathological role of this globulin in the increased capillary permeability has not been established.

Capillary Permeability↗
PubMed1984

Alterations in high-affinity binding characteristics and levels of opioids in invertebrate ganglia during aging: evidence for an opioid compensatory mechanism.

In Mytilus and Leucophaea the high-affinity binding site density is significantly lower in old animals than in young animals, whereas the low-affinity site density remains unchanged. In Mytilus the estimated met-enkephalin and met-enkephalin-Arg6-Phe7 levels are significantly higher in old than in young animals. In Leucophaea only the met-enkephalin level can be determined, and it is also higher in old animals. The decrease in the high-affinity binding site density and the corresponding increase in endogenous enkephalin levels suggest the existence of an opioid compensatory mechanism associated with the aging process. In Mytilus there is a demonstrated decrease with age in intraganglionic dopamine levels in response to applied opiates. In addition, the inhibition of dopamine-stimulated adenylate cyclase activity by opiates also decreases in older animals. In Leucophaea the sex difference in opioid binding densities diminishes with age.

Adenylyl Cyclases↗
PubMed1984

A note on stability in force applied to control a repetitive task with the legs.

The forces applied to pedals during cycling were collected every 40 ms from approximately 29,000 movement repetitions. Intra-cycle mean values of force and its variability were significantly correlated, supporting Schmidt's impulse variability theory of within-movement activities of the legs. In addition, as mean forces approached peak values, coefficients of variation decreased. From averages taken minute by minute, intra-cycle forces were seen to rise or fall in concert, implying that the pattern as a whole constituted a significant neuro-muscular unit of control.

Journal Article↗
PubMed1984

[Major hypokalemia with rhabdomyolysis secondary to the intake of a nonalcoholic aniseed aperitif].

A case of exogenous hypermineralocorticism secondary to absorption of an alcohol-free liquorice beverage is reported here. The patient was a 53 year old man with known alcoholic liver cirrhosis who had stopped drinking alcohol one year earlier. He was admitted to the hospital for fever and myalgia without hypertension. Laboratory tests showed severe hypokalemia (1.7 mmol/l), metabolic acidosis and enzyme abnormalities compatible with rhabdomyolysis. Urinary potassium excretion was high. Plasma renin activity and aldosterone levels were low. Symptoms were those of exogenous hypermineralocorticism. One month earlier, the patient had drunk 0,25 1 per day of an alcohol-free licorice beverage for two weeks. Clinical and biological symptoms disappeared with potassium loading alone. Three weeks later, when serum potassium levels remained normal, the ingestion of the same amounts of the same beverage produced an important decrease in serum potassium levels. Intoxication by liquorice is a well-known cause of pseudoprimary hyperaldosteronism. But the case reported here has some unique features. It is, to our knowledge, the first case reported in the literature, although a few cases have been brought to the attention of the poison center in Marseille. The amount of beverage ingested was small (0.35 g/day of glycyrrhizinic acid) as compared to the usual threshhold of toxicity (0.7 g/day). The toxic effects lasted two weeks after discontinuing ingestion. Cirrhotic patients may be more susceptible than others but the main consumers of this type of beverage are presumably ex-alcoholics.

Beverages↗