Immunotherapy of lewis lung carcinoma with hydrosoluble peptidoglycan monomer (PGM)

The water-soluble peptidoglycan monomer (PGM) isolated from the culture fluid of Brevibacterium divaricatum, which has immunostimulating activity, has been examined for its antitumor effects in C57BL mice bearing Lewis lung carcinoma. The formation of spontaneous lung metastases from SC tumor implants is significantly inhibited. The growth of SC primary tumors, including advanced ones, is also significantly inhibited, though to a less pronounced extent than the growth of metastases. The effects on metastases are evident with all treatment schedules used, whereas those on SC primary tumors are treatment schedule-dependent. The treatment with PGM was found to be therapeutically useful when combined with surgical removal of IM implants; in conditions where a single post-operative treatment was ineffective, combined post-operative and immediately pre-operative administration of PGM significantly increased (by 40%) the survival time of treated animals over that of controls undergoing surgery only.     

Peptide inhibitors of E. collagenolyticum bacterial collagenase--effect of N-methylation. Consequences on biological activity and conformational properties.

Peptide inhibitors of E. collagenolyticum bacterial collagenase, HS-CH2-CH2-CO-Pro-Yaa (Yaa = Ala, Leu, Nle), have been N-methylated at the Yaa position. The N-methylation slightly increases the inhibitory potency of the modified peptides as compared to the parent compounds. The conformational effects of the N-methylation have been investigated by both 1H 2D-NMR and molecular mechanics energy minimization. Three low-energy conformers have been predicted for the unmethylated parent compounds (Yaa = Ala, Leu, Nle). They are characterized by the psi value of the central proline residue: psi Pro = 150 degrees (trans' conformation), psi Pro = 70 degrees (C7 conformation) and psi Pro = -50 degrees (cis' conformation). The N-methylation has been found to strongly increase the energy of the C7 conformer and to a less extent the energy of the cis' conformer. This leaves the trans' conformation as the only low-energy conformer. The ROESY experiments have established that both the N-methyl peptides and the parent compounds adopt the same preferred backbone conformation in water solution, i.e. the trans' conformation. Based on these results, the activities of the N-methyl peptides are discussed and a possible conformation of the inhibitor in the bound state is proposed.     

Metabolic characteristics of bacterial cells entrapped in beaded calcium alginate and/or pectate gels

A mixture of heterotrophic bacteria and collection strains ofEscherichia coli andPseudomonas fluorescens were immobilized in calcium alginate or pectate gels. Comparison of respiratory activity, substrate uptake and biosynthetic capacity of immobilized cells showed that both types of carriers permit a prolonged preservation of metabolic activity but the transfer of substances through the gel is faster in the pectate. Morphological changes include some intracellular structures, partial shrinkage of the plasma membrane of immobilized cells, and transformation of a rod-like cell shape to an oval one.     

Laboratory investigation and infection control of cholera in Kingston,Ont.

Vibrio cholerae, biotype El Tor, was isolated in a hospital laboratory in Kingston, Ont. in 1974. Confirmation and complete identification by the Ontario regional and provincial public health laboratories was obtained within 3 days. Institution of well established infection-control and public health measures prevented spread of the infection within the hospital and the community.     

Cognitive and affective outcomes of teaching about poisonous and venomous animals

ABSTRACT

The use of live animals in instruction plays an important role in biological education, with the intention that attitudes and emotions should be positively influenced. To date, studies in this field have given mixed results, and there has certainly been a lack of studies on student attitudes and knowledge of poisonous and venomous animals. This study focuses on the effect of the use of poisonous and venomous animals in biology instruction. Two treatment groups of Slovenian seventh and eighth graders (N = 123; age 12.3 and 13.2 years, respectively) were compared. The experimental group (N = 82) was given the opportunity to observe with adequate risk assessment live animal species. The observation of live poisonous and venomous animals led to higher values on different attitudinal dimensions. After instruction, we found no differences between both treatment groups in knowledge. Interest in learning about the different poisonous and venomous animals increased significantly. The level of disgust decreased for the viper, spider, and scorpion. However, ‘fear’ seems to be more stable and less influenceable than ‘disgust’. We recommend that students should be offered as many first-hand experiences with live poisonous and venomous animals as possible mainly through informal learning environments, such as zoos.     

Secretory carcinoma of the breast. Report of a case with fine needle aspiration biopsy

A case of secretory carcinoma of the breast in a 48-year-old woman studied by fine needle aspiration (FNA) cytology is presented. The prominent intracytoplasmic vacuolization and numerous signet-ring forms and the presence of sheets of neoplastic cells with large intercellular spaces should permit its diagnosis in FNA specimens. The differential diagnosis of this rare lesion from other breast neoplasms that show similar features is discussed.