Acyclic permutants of naturally occurring cyclic proteins - Characterization of cystine knot and beta-sheet formation in the macrocyclic polypeptide kalata B1

Kalata B1 is a prototypic member of the unique cyclotide family of macrocyclic polypeptides in which the major structural features are a circular peptide backbone, a triple stranded beta-sheet, and a cystine knot arrangement of three disulfide bonds. The cyclotides are the only naturally occurring family of circular proteins and have prompted us to explore the concept of acyclic permutation, i.e. opening the backbone of a cross-linked circular protein in topologically permuted ways. We have synthesized the complete suite of acyclic permutants of kalata B1 and examined the effect of acyclic permutation on structure and activity. Only two of six topologically distinct backbone loops are critical for folding into the native conformation, and these involve disruption of the embedded ring in the cystine knot. Surprisingly, it is possible to disrupt regions of the p-sheet and still allow folding into native-like structure, provided the cystine knot is intact. Kalata B1 has mild hemolytic activity, but despite the overall structure of the native peptide being retained in all but two cases, none of the acyclic permutants displayed hemolytic activity. This loss of activity is not localized to one particular region and suggests that cyclization is critical for hemolytic activity.

Perforin-mediated cytotoxicity is critical for surveillance of spontaneous lymphoma

Immune surveillance by cytotoxic lymphocytes against cancer has been postulated for decades, but direct evidence for the role of cytotoxic lymphocytes in protecting against spontaneous malignancy has been lacking. As the rejection of many experimental cancers by cytotoxic T lymphocytes and natural killer cells is dependent on the pore-forming protein perforin (pfp), we examined pfp-deficient mice for increased cancer susceptibility. Here we show that pfp-deficient mice have a high incidence of malignancy in distinct lymphoid cell lineages (T, B, NKT), indicating a specific requirement for pfp in protection against lymphomagenesis. The susceptibility to lymphoma was accentuated by simultaneous lack of expression of the p53 gene, mutations in which also commonly predispose to human malignancies, including lymphoma. In contrast, the incidence and age of onset of sarcoma was unaffected in p53-deficient mice. Pfp-deficient mice were at least 1,000-fold more susceptible to these lymphomas when transplanted, compared with immunocompetent mice in which tumor rejection was controlled by CD8(+) T lymphocytes. This study is the first that implicates direct cytotoxicity by lymphocytes in regulating lymphomagenesis.

Accelerating seismic energy release and evolution of event time and size statistics: Results from two heterogeneous cellular automaton models

The evolution of event time and size statistics in two heterogeneous cellular automaton models of earthquake behavior are studied and compared to the evolution of these quantities during observed periods of accelerating seismic energy release Drier to large earthquakes. The two automata have different nearest neighbor laws, one of which produces self-organized critical (SOC) behavior (PSD model) and the other which produces quasi-periodic large events (crack model). In the PSD model periods of accelerating energy release before large events are rare. In the crack model, many large events are preceded by periods of accelerating energy release. When compared to randomized event catalogs, accelerating energy release before large events occurs more often than random in the crack model but less often than random in the PSD model; it is easier to tell the crack and PSD model results apart from each other than to tell either model apart from a random catalog. The evolution of event sizes during the accelerating energy release sequences in all models is compared to that of observed sequences. The accelerating energy release sequences in the crack model consist of an increase in the rate of events of all sizes, consistent with observations from a small number of natural cases, however inconsistent with a larger number of cases in which there is an increase in the rate of only moderate-sized events. On average, no increase in the rate of events of any size is seen before large events in the PSD model.

Hair morphine concentrations of fatal heroin overdose cases and living heroin users

Aims To compare heroin and other opiate use of heroin overdose fatalities, current street heroin users and drug-free therapeutic community clients. Design Hair morphine concentrations that assess heroin use and other opiate use in the 2 months preceding interview or death were compared between heroin overdose fatalities diagnosed by forensic pathologists (fOD) (n = 42), current street heroin users (CU) (n = 100) and presumably abstinent heroin users in a drug-free therapeutic community (TC) (n = 50). Setting Sydney, Australia. Findings The mean age and gender breakdown of the three samples were 32.3 years, 83% male (FOD), 28.7 years, 58% male (CU) and 28.6 years, 60% male (TC). The median blood morphine concentration among the FOD cases was 0.35 mg/l, and 82% also had other drugs detected. There were large differences between the three groups in hair morphine concentrations, with the CU group (2.10 ng/mg) having concentration approximately four times that of the FOD group (0.53 ng/mg), which in turn had a concentration approximately six times that of the TC group (0.09 ng/mg). There were no significant differences between males and females in hair concentrations within any of the groups. Hair morphine concentrations were correlated significantly with blood morphine concentrations among FOD cases (r = 0.54), and self-reported heroin use among living participants (r = 0.57). Conclusions The results indicate that fatal cases had a lower degree of chronic opiate intake than the active street users, but they were not abstinent during this period.

Four cases of equine polysaccharide storage myopathy in the United Kingdom

This paper describes four cases of equine polysaccharide storage myopathy which were confirmed by histological examination of muscle biopsy specimens. The horses were of mixed breeding, with warmblood and thoroughbred dominating. They all had recurrent episodes of rhabdomyolysis, indicated by clinical signs and increased plasma levels of muscle enzymes. They were managed conservatively and have continued athletic careers despite their disease.

Site-directed mutagenesis of dimethylsulfoxide reductase from Rhodobacter capsulatus: The critical roles of tyrosine-114 and tryptophan-116

The crystal structure of six functionally-distinct enzymes of the DMSO reductase family of molybdenum enzymes has revealed that the tertiary structure of the polypeptide that binds the bis(MGD)Mo cofactor is highly conserved. Differences in the catalytic properties of enzymes of this family are almost certainly dependent upon differences in the structure ofthe MO active site. In DMSO reductase from Rhodobacter species tryptophan- 116 (W 116) hydrogen-bonds to an 0x0 group coordinated to the MO ion. In addition a second amino acid side chain from tyrosine-114 (Y 114) is in close proximity to the 0x0 group. We have investigated the role of Y 114 and W 116 in DMSO reductase using site-directed mutagenesis,

Royal Australian and New Zealand College of Psychiatrists clinical practice guidelines for the treatment of schizophrenia and related disorders

Background: The Royal Australian and New Zealand College of Psychiatrists is co-ordinating the development of clinical practice guidelines (CPGs) in psychiatry, funded under the National Mental Health Strategy (Australia) and the New Zealand Health Funding Authority. This paper presents CPGs for schizophrenia and related disorders. Over the past decade schizophrenia has become more treatable than ever before. A new generation of drug therapies, a renaissance of psychological and psychosocial interventions and a first generation of reform within the specialist mental health system have combined to create an evidence-based climate of realistic optimism. Progressive neuroscientific advances hold out the strong possibility of more definitive biological treatments in the near future. However, this improved potential for better outcomes and quality of life for people with schizophrenia has not been translated into reality in Australia. The efficacy-effectiveness gap is wider for schizophrenia than any other serious medical disorder. Therapeutic nihilism, under-resourcing of services and a stalling of the service reform process, poor morale within specialist mental health services, a lack of broad-based recovery and life support programs, and a climate of tenacious stigma and consequent lack of concern for people with schizophrenia are the contributory causes for this failure to effectively treat. These guidelines therefore tackle only one element in the endeavour to reduce the impact of schizophrenia. They distil the current evidence-base and make recommendations based on the best available knowledge. Method: A comprehensive literature review (1990-2003) was conducted, including all Cochrane schizophrenia reviews and all relevant meta-analyses, and a number of recent international clinical practice guidelines were consulted. A series of drafts were refined by the expert committee and enhanced through a bi-national consultation process. Treatment recommendations: This guideline provides evidence-based recommendations for the management of schizophrenia by treatment type and by phase of illness. The essential features of the guidelines are: (i) Early detection and comprehensive treatment of first episode cases is a priority since the psychosocial and possibly the biological impact of illness can be minimized and outcome improved. An optimistic attitude on the part of health professionals is an essential ingredient from the outset and across all phases of illness. (ii) Comprehensive and sustained intervention should be assured during the initial 3-5 years following diagnosis since course of illness is strongly influenced by what occurs in this 'critical period'. Patients should not have to 'prove chronicity' before they gain consistent access and tenure to specialist mental health services. (iii) Antipsychotic medication is the cornerstone of treatment. These medicines have improved in quality and tolerability, yet should be used cautiously and in a more targeted manner than in the past. The treatment of choice for most patients is now the novel antipsychotic medications because of their superior tolerability and, in particular, the reduced risk of tardive dyskinesia. This is particularly so for the first episode patient where, due to superior tolerability, novel agents are the first, second and third line choice. These novel agents are nevertheless associated with potentially serious medium to long-term side-effects of their own for which patients must be carefully monitored. Conventional antipsychotic medications in low dosage may still have a role in a small proportion of patients, where there has been full remission and good tolerability; however, the indications are shrinking progressively. These principles are now accepted in most developed countries. (vi) Clozapine should be used early in the course, as soon as treatment resistance to at least two antipsychotics has been demonstrated. This usually means incomplete remission of positive symptomatology, but clozapine may also be considered where there are pervasive negative symptoms or significant or persistent suicidal risk is present. (v) Comprehensive psychosocial interventions should be routinely available to all patients and their families, and provided by appropriately trained mental health professionals with time to devote to the task. This includes family interventions, cognitive-behaviour therapy, vocational rehabilitation and other forms of therapy, especially for comorbid conditions, such as substance abuse, depression and anxiety. (vi) The social and cultural environment of people with schizophrenia is an essential arena for intervention. Adequate shelter, financial security, access to meaningful social roles and availability of social support are essential components of recovery and quality of life. (vii) Interventions should be carefully tailored to phase and stage of illness, and to gender and cultural background. (viii) Genuine involvement of consumers and relatives in service development and provision should be standard. (ix) Maintenance of good physical health and prevention and early treatment of serious medical illness has been seriously neglected in the management of schizophrenia, and results in premature death and widespread morbidity. Quality of medical care for people with schizophrenia should be equivalent to the general community standard. (x) General practitioners (GPs)s should always be closely involved in the care of people with schizophrenia. However, this should be truly shared care, and sole care by a GP with minimal or no special Optimal treatment of schizophrenia requires a multidisciplinary team approach with a consultant psychiatrist centrally involved.

Endoscopic removal of eroded adjustable gastric band: lessons learned after 5 years and 78 cases

Background: One of the complications of laparoscopic adjustable gastric banding is intragastric erosion, leading to a revisional procedure to remove the band. Our aim was to present the procedure and results of endoscopic band removal in a 5-year multicenter experience from the Gastro Obeso Center and Universidade de Sao Paulo, Sao Paulo, and Universidade Federal de Pernambuco, Recite, Brazil. Methods: From 2003 to 2008, 82 patients were diagnosed with band erosion. The clinical data concerning the endoscopic procedure were prospectively recorded and retrospectively reviewed. Results: The average preoperative body mass index was 43.2 kg/m(2) (range 34-50). At the diagnosis of intragastric erosion, the body mass index was 24-41 kg/m(2) (average 31.8). The erosion occurred an average of 16.3 months (range 6-36) postoperatively. The symptoms included pain in 25 (31%), port infection in 21 patients (27%), and weight regain in 20 (25%), and 12 patients (15%) were asymptomatic. Endoscopic removal was possible for 78 patients (95%). In 85% of patients, the band was removed in the first session, with an average duration of 55 minutes (range 25-150). Five cases of pneumoperitoneum occurred after the procedure. Of these, 3 were treated conservatively, 1 was treated by laparoscopy, and I was treated by abdominal puncture using the Veress needle. Conclusion: Endoscopic removal of eroded laparoscopic adjustable gastric banding is safe and effective. It can be used as a first choice procedure in clinical practice. (Surg Obes Relat Dis 2010; 6:423-428.) (C) 2010 American Society for Metabolic and Bariatric Surgery. All rights reserved.