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Biomedical subjects

K May

Publications and source records attributed to K May.

At least 73 records · Page 4Linked to original sources
PubMed1979

Ferritin, a sensitizing substance in the leucocyte migration inhibition test in patients with malignant lymphoma.

The nature of the factor in Hodgkin's disease involved spleen to which many patients with malignant lymphoma react in the leucocyte migration inhibition test has been investigated. Our results suggest that ferritin from Hodgkin's disease involved spleens is antigenically different to that prepared from normal spleen. Isoelectric focusing shows the presence of more acidic 'isoferritins' in ferritin prepared from Hodgkin's disease involved spleen than in that prepared from normal spleen. Further observations using the leucocyte migration inhibition test suggest that sensitization to the abnormal ferritin, acting as an onco-fetal tumour associated substance, may be responsible for the reaction of patients with malignant lymphoma in this test.

Antigens, Neoplasm↗
PubMed1965

[Periodic disease].

Explore the source record for details and available documents.

Familial Mediterranean Fever↗
PubMedDate not supplied

An investigation of the main mutagenic components of a carcinogenic oil by fractionation and testing in the modified Ames assay.

A low-viscosity carcinogenic oil was extracted with dimethylsulphoxide (DMSO) and the extract fractionated into 1-3 ring aromatic components, 4-6 ring polycyclic aromatic compounds (PCAs) and polar materials. Each of these fractions was tested in the Mobil modified Ames assay at the same concentration as in the DMSO extract, alongside unfractionated DMSO extracts from the same oil and two reference oils. In addition the fractions were combined in various ways to examine inhibitory or additive effects. Clear positive findings were obtained with the DMSO extract of the main test oil, with some reduction in activity in a sample (the starting material for fractionation) that was back-extracted to remove DMSO. Of the three fractions tested on their own and assessed in terms of mutagenicity index, the 1-3 ring aromatic fraction had the greatest mutagenic activity, showing similar activity to the starting material, whereas the 4-6 ring PCA fraction had much lower activity and the polar fraction showed the lowest activity with an absence of doubling in one of the tests. The polar fraction showed signs of an inhibitory effect on the response to the 1-3 ring aromatic fraction and to a questionable extent on that of the 4-6 ring PCA fraction. Although a low level of the 4-6 ring PCA fraction showed some inhibitory effect on the response to the 1-3 ring aromatic fraction, a low level of the 1-3 ring aromatic fraction added to the 4-6 ring PCA fraction enhanced the response.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinogens↗
PubMedDate not supplied

Assessment of the ability of 4CMB and 4HMB to induce primary genetic damage in strains of Escherichia coli.

Studies were undertaken to investigate the ability of 4CMB and 4HMB to induce primary DNA damage in bacteria as shown by differential lethality in strains of E. coli proficient and deficient in DNA repair. It has been demonstrated in these laboratories that the assay system used will detect weak DNA-damaging agents by the use of a prolonged incubation period and, where appropriate, the inclusion of an S9 mix activating system. Both 4CMB and 4HMB induced primary DNA damage in E. coli, giving similar responses in the presence and absence of S9 mix. A comparison based on the response at the lowest inclusion level (250 microgram/ml) indicates that 4CMB was more active. 4CMB also caused greater lethality in a uvrA-, recA-, lexA- strain than in the other repair-deficient (uvrA-, polA-) strain employed. 4HMB was approximately equitoxic to both repair-deficient strains. It is suggested that this difference may be explained it both chemicals cause DNA lesions recognized by the uvrA system, and 4CMB causes additional lesions recognised or repaired by the recA or lexA systems.

Biphenyl Compounds↗
PubMedDate not supplied

Activity of 4CMB and 4HMB in bacterial mutation assays.

Conventional pour-plate tests were conducted using 5 Strains of S. typhimurium and 1 E. coli strain. The range of levels examined was 1.6-100 microgram per plate, for both chemicals. 4HMB was inactive in all tests. 4CMB was directly active in all strains, inducing both frameshift and base-substitution mutations in a dose-dependent manner. The largest responses were recorded in strains TA1538 and TA98.

Biphenyl Compounds↗
PubMedDate not supplied

Captopril alters schedule induced polydipsia, urination, and defecation in rats.

Schedule induced polydipsia, urination and defecation were examined in rats that received training on a fixed interval 2 min schedule of food reinforcement. In Phase I of the experiment, animals received peripheral injections of captopril (an angiotensin conversion enzyme blocker, 0.5 or 50 mg/kg), or equivalent volumes of 0.9% saline. The results showed that low doses of captopril (0.5 mg/kg) significantly increased both operant responding and the adjunctive behaviors. High peripheral doses of captopril significantly reduced responding and schedule induced behavior. In Phase II of the experiment, animals received either low peripheral doses of captopril (sc 0.5 mg/kg), or low doses that were coupled with central injections (i.e., 0.12 mg icv + 0.5 mg/kg sc). As observed in Phase I, low peripheral doses of captopril enhanced behavior, but the enhancement effect was eliminated with low (0.12 mg) central administration. The overall results are consistent with past research examining captopril effects on non-operant, meal-induced drinking. Yet since captopril affected operant responding and adjunctive behaviors similarly, the findings suggest that angiotensin plays a common role in the motivational processes that precede and follow the arrival of food.

Analysis of Variance↗