TsTX-IV, a short chain four-disulfide-bridged neurotoxin from Tityus serrulatus venom which acts on Ca2+-activated K+ channels.

The primary structure of TsTX-IV, a neurotoxin isolated from Tityrus serrulatus scorpion venom, is reported. Its amino acid sequence was determined by automated Edman sequential degradation of the reduced and carboxymethylated toxin and of relevant peptides obtained by digestion with Staphylococcus aureus strain V8 protease or trypsin and cleavage by CNBr. The complete sequence showed 41 amino acid residues, which account for an estimated molecular weight of 4520, and eight half-cystine residues which cross-link the toxin molecule with four disulfide bonds. The molecular weight determined by mass spectrometry was 4518. Comparison of this sequence with those from other scorpion toxins showed a resemblance with toxins which act on different types of K+ channels. TsTx-IV was able to block Ca2+-activated K+ channels of high conductance. TsTX-IV is the first four-disulfide-bridged short toxin from T. serrulatus so far completely sequenced.     

Exploring the decision-making preferences of people with colorectal cancer

OBJECTIVES: To explore patient views on participation in treatment, physical care and psychological care decisions and factors that facilitate and hinder patients from making decisions. DESIGN: Qualitative study using semi-structured interviews with patients. SETTING AND PARTICIPANTS: Three NHS Trusts in the north-west of England. Theoretical sampling including 41 patients who had been treated for colorectal cancer. RESULTS: For patients, participation in the decision-making process was about being informed and feeling involved in the consultation process, whether patients actually made decisions or not. The perceived availability of treatment choices (surgery, radiotherapy, chemotherapy) was related to type of treatment. Factors that impacted on whether patients wanted to make decisions included a lack of information, a lack of medical knowledge and trust in medical expertise. Patients perceived that they could have a more participatory role in decisions related to physical and psychological care. CONCLUSION: This study has implications for health professionals aiming to implement policy guidelines that promote patient participation and shared partnerships. Patients in this study wanted to be well informed and involved in the consultation process but did not necessarily want to use the information they received to make decisions. The presentation of choices and preferences for participation may be context specific and it cannot be assumed that patients who do not want to make decisions about one aspect of their care and treatment do not want to make decisions about other aspects of their care and treatment.     

Effects of eggplant (Solanum melongena) on the atherogenesis and oxidative stress in LDL receptor knock out mice (LDLR(-/-)).

Eggplant (Solanum melongena) has been used as hypocholesterolemic agent in many countries. However, few controlled studies were addressed to this subject and atherogenesis. We have evaluated the effect of eggplant on cholesterol metabolism and atherogenesis in LDLR(-/-) mice. Animals were fed on chow (n=17) or atherogenic (n=21) diet during 12 weeks receiving water (control) or eggplant extract. Liver, serum and fecal lipids, together with serum lipoproteins were measured. Oxidative stress was evaluated through conjugate diene formation and ox-LDL antibodies by enzyme immunoassay. Atherosclerotic lesions were measured in different sites of aorta. Total cholesterol and atherogenic lipoproteins did not decrease after eggplant intake. Animals receiving eggplant and chow diet showed increased anti-ox-LDL antibodies and a decreased lag phase of conjugated diene formation, indicating a higher oxidative stress than controls. No differences were seen in lesion area of aortic valve. Eggplant extract had high histamine and other amine levels that could enhance LDL oxidation and its endocytosis. Eggplant did not decrease plasma cholesterol nor prevent the development of atherosclerosis in LDLR(-/-) mice. Surprisingly, eggplant increased oxidative stress, representing a risk factor for atherosclerosis. These results did not support the use of eggplant extract as hypocholesterolemic agent.