The biology of the opioid growth factor receptor (OGFr).

This review is aimed to provide a concise yet extensive survey of key short bioactive peptide sequences for a range of applications ranging from biomaterials development to peptides with therapeutic uses. The following are considered: cell adhesion motifs, structural peptides, cell-penetrating and tumor-homing peptides, antimicrobial peptides, peptide hormones, growth factors and matrix metalloprotease substrates, neuropeptides, amyloid peptides, antioxidant peptides, peptide affinity tags, anticancer peptides, and others. This review provides a convenient resource, summarizing a broad range of important sequences with great utility as a resource concerning both small peptide drugs and also novel biofunctional peptide-based materials.

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Small Bioactive Peptides for Biomaterials Design and Therapeutics

The role of tumour necrosis factor (TNF-alpha) in experimental autoimmune uveoretinitis (EAU).

Although significant improvement has been made in the treatment of pain in the postoperative period, many patients still experience unnecessary discomfort resulting in distress, higher morbidity and prolonged stay in hospital. The standard pillar of postoperative treatment of severe pain is the use of opioids. However, adverse reactions to opioids make their use unfavourable. A better understanding of the pathophysiology of pain has helped clinicians to a more balanced approach to postoperative pain treatment. The development of the multimodal approach to postoperative analgesia, with the use of different drugs acting via different routes to give good analgesia, with minimal side-effects, represents a major development in the treatment of postoperative pain. Early, aggressive mobilisation and feeding must follow in order to restore normal conditions quickly. Alternatives to opioids should be used as extensively as possible. Local anaesthesia, used as regional blocks or as wound infiltration, is most beneficial. Paracetamol has good basic analgesic properties, and should probably be used in dosages higher than recommended today. The combination with a NSAID results in better and longer-lasting analgesia. The intravenous form propacetamol will increase the possibilities of its use. The new concept of selective COX-2 inhibiting NSAIDs will result in analgesic and anti-inflammatory drugs with fewer side-effects. The well-known inexpensive group of corticosteroids have good analgesic and anti-emetic properties, and are especially interesting to use in patients who do not tolerate NSAIDs. The alpha2-receptor agonists like clonidine, when administered epidurally or intrathecally, are useful adjuncts, but their adverse effects on sedation and hypotension limit their use. NMDA-receptor antagonists are of limited value in the postoperative period. Adenosine and neostigimine are still on a research level but may lead to new, clinically useful analgesic drugs. In the future, cannabinoids, cholecystokinin-receptor antagonists and neurokinin-1 antagonists may become important analgesic drugs.

https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-6576.2000.441003.x

Non-opioid postoperative analgesia.

Molecular mimicry and autoimmune disease

Splenopentin (SP-5, Arg-Lys-Glu-Val-Tyr) and thymopentin (TP-5, Arg-Lys-Asp-Val-Tyr) are synthetic immunomodulating peptides corresponding to the region 32-34 of a splenic product called splenin (SP) and the thymic hormone thymopoietin (TP), respectively. TP was originally isolated as a 5-kDa (49-amino acids) protein from bovine thymus while studying effects of the thymic extracts on neuromuscular transmission and was subsequently observed to affect T cell differentiation and function. TP I and II are two closely related polypeptides isolated from bovine thymus. A radioimmunoassay for TP revealed a crossreaction with a product found in spleen and lymph node. This product, named splenin, differs from TP only in position 34, aspartic acid for bovine TP and glutamic acid for bovine splenin and it was called TP III as well. Synthetic pentapeptides (TP-5) and (SP-5), reproduce the biological activities of TP and SP, respectively. It is now evident that various forms of TPs were created by proteolytic cleavage of larger proteins during isolation. cDNA clones have been isolated for three alternatively spliced mRNAs that encodes three distinct human T cell TPs. The immunomodulatory properties of TP, SP, TP-5, SP-5 and some of their synthetic analogs reported in the literature have been briefly reviewed.

Thymopentin and splenopentin as immunomodulators. Current status.

The role of retinal antigens in Eales’ disease was studied in 24 patients and an equal number of healthy controls. Lymphocyte proliferative responses were tested in vitro against native S-antigen, its uveitopathogenic peptides (peptide M and peptide G), yeast histone H3 peptide and uveitopathogenic fragment of interphotoreceptor retinoid-binding protein (IRBP; R16) to establish their role in the pathogenesis of Eales’ disease. Out of 24 Eales’ disease patients, 6 showed significant proliferative response against S-antigen, its uveitogenic fragments or IRBP. None among the controls showed any response to any retinal antigen used in this study. There was no statistically significant difference in the response to purified protein derivative between patients and controls. These results suggest that retinal antigens may play a role in the etiopathogenesis of Eales’ disease. An extraneous agent that could result in exposure of normally sequestered uveitopathogenic antigens of the immune system, leading to an exuberant immune response in the eye may initiate the disease.

Cellular Immune Response to Retinal S-Antigen and Interphotoreceptor Retinoid-Binding Protein Fragments in Eales’ Disease Patients

Endogenous opioid peptides and opiates like morphine produce their pharmacological effects through the membrane bound opioid receptors. These receptors belong to a superfamily of G-protein-coupled rec

Molecular biology of opioid receptors: recent advances.

Uveitis is an intraocular inflammatory disease that mostly affects children and young adults. It is one of the major causes of blindness in young individuals in India and the world. It is responsible for about 10 per cent of total visual impairment. Unfortunately, etiological diagnosis is not evident in a majority of these patients. It is generally felt that autoimmune mechanism may be involved in so called 'idiopathic' cases which has led to search for the putative autoantigens in experimental animal models. It has been demonstrated that experimental autoimmune uveitis (EAU) can be elicited against several retinal proteins in rats, mice and sub-human primates. These include the S-antigen, a major protein on retinal photoreceptor cell, interphotoreceptor retinoid binding protein (IRBP) and several others. There are many similarities between clinical entities and the EAU, but the EAU differs from the clinical conditions in being self-limited, and requiring complete Freund's adjuvant for induction of the disease. The disease can be induced only in susceptible strains. Nevertheless, use of the EAU model has allowed for identification of disease causing epitopes of antigens and evaluation of disease modifying strategies which could be applied in clinical situations. There has been significant progress in this field, but still a lot more is required to be learnt to translate it into clinical practice.

S. Biswas

Papers

Thymopentin and splenopentin as immunomodulators. Current status.

Cellular Immune Response to Retinal S-Antigen and Interphotoreceptor Retinoid-Binding Protein Fragments in Eales’ Disease Patients

Molecular biology of opioid receptors: recent advances.

Experimental autoimmune uveitis as animal model for human posterior uveitis

Augmentation of human natural killer cells by splenopentin analogs