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Ian Smith

Publications and source records attributed to Ian Smith.

At least 19 recordsLinked to original sources
PubMed2004

The high resolution crystal structure of a native thermostable serpin reveals the complex mechanism underpinning the stressed to relaxed transition.

Serpins fold into a native metastable state and utilize a complex conformational change to inhibit target proteases. An undesirable result of this conformational flexibility is that most inhibitory serpins are heat sensitive, forming inactive polymers at elevated temperatures. However, the prokaryote serpin, thermopin, from Thermobifida fusca is able to function in a heated environment. We have determined the 1.8 A x-ray crystal structure of thermopin in the native, inhibitory conformation. A structural comparison with the previously determined 1.5 A structure of cleaved thermopin provides detailed insight into the complex mechanism of conformational change in serpins. Flexibility in the shutter region and electrostatic interactions at the top of the A beta-sheet (the breach) involving the C-terminal tail, a unique structural feature of thermopin, are postulated to be important for controlling inhibitory activity and triggering conformational change, respectively, in the native state. Here we have discussed the structural basis of how this serpin reconciles the thermodynamic instability necessary for function with the stability required to withstand elevated temperatures.

Binding Sites↗
PubMed2004

Towards a comprehensive view of the primary structure of venom proteins from the parasitoid wasp Pimpla hypochondriaca.

Venom from the parasitoid wasp Pimpla hypochondriaca has potent in vivo activity against insect haemocytes and disrupts host immune responses. Using hybridisation techniques, and more recently random sequence analysis, we had previously identified cDNAs encoding 10 venom proteins from this wasp and deduced their primary structures. We have now extended the random sequence analysis and discovered a further nine cDNAs encoding proteins with predicted signal sequences. The mature proteins were calculated to have masses of between 4 and 22 kDa. Post-signal sequence residues predicted from the cDNAs matched those derived by Edman degradation from venom proteins separated using gel filtration and reverse phase chromatography, confirming that the cloned cDNAs encode proteins which are secreted into the venom sac. Proteins containing at least six cysteine residues were abundant and seven of these cysteine-rich venom proteins, cvp1-7, were identified. The sequences of some of these proteins were similar, or contained similar cysteine arrangements, to Kunitz type protease inhibitors, pacifastin, the trypsin inhibitor domain protein family, atracotoxin and omega-conotoxin, respectively, which occur in a diverse range of animals including spiders, molluscs, humans and grasshoppers. Two small venom proteins, svp1 and svp2, as well as cvp7 did not have similar sequences to proteins in the GenBank protein database suggesting they may be highly specialised venom components. The random sequencing approach has provided a rapid means of determining the primary structure of the majority of Pimpla hypochondriaca venom proteins.

Amino Acid Sequence↗
PubMed2004

Maximizing clinical benefit with trastuzumab.

To optimize patient management in breast cancer a number of factors are considered, including hormone receptor and HER2 status. A feasible approach for women with less aggressive, estrogen receptor/HER2-positive metastatic breast cancer is to consider trastuzumab (Herceptin; F. Hoffmann-La Roche, Basel, Switzerland) combined with endocrine therapy. Randomized clinical trials are ongoing to assess the combination of trastuzumab with aromatase inhibitors. In patients with aggressive HER2-positive metastatic breast cancer, trastuzumab/chemotherapy combination regimens are warranted. When administered first line in combination with a taxane, trastuzumab improves all clinical outcome parameters, including survival, in such patients. Trastuzumab adds little to the toxicity profile of taxanes, and trastuzumab combination therapy is associated with improvements in quality of life when compared with chemotherapy alone. There is encouraging evidence of improved efficacy when trastuzumab is combined with other cytotoxic agents with proven single-agent activity in breast cancer, including capecitabine (Xeloda; F. Hoffmann-La Roche), gemcitabine, and vinorelbine. Trastuzumab is also being investigated as part of triplet drug regimens. Trastuzumab has good single-agent activity in first-line therapy. This is of relevance to women with HER2-positive disease who are not suitable for, or do not wish to receive, cytotoxic chemotherapy. The benefits noted with trastuzumab-containing regimens were documented in clinical trials where trastuzumab was given until disease progression. A further rationale exists to continue trastuzumab beyond progression. Data from retrospective reviews indicate that this strategy is feasible.

Antibodies, Monoclonal↗
PubMed2003

Aromatase inhibitors in early breast cancer treatment.

A recent National Institutes of Health consensus guideline recommends the general use of adjuvant hormonal therapy for the treatment of early breast cancer in postmenopausal women with estrogen receptor-positive tumors. Standard therapy has been 5 years of tamoxifen, but about 30% of those patients fail to survive 10 years, many as a consequence of tamoxifen resistance. Promising results with the third-generation aromatase inhibitors anastrozole, letrozole, and exemestane in first- and second-line treatment of metastatic breast cancer has prompted their evaluation as adjuvant therapy in patients progressing on tamoxifen or as alternative first-line treatment. Anastrozole has recently achieved significantly longer disease-free survival than tamoxifen in a first-line adjuvant therapy trial, and letrozole is being investigated in several large adjuvant trials. Aromatase inhibitors appear to be well tolerated for long-term adjuvant treatment. In the neoadjuvant setting, letrozole has been especially effective compared with tamoxifen in downstaging primary tumors in postmenopausal women, permitting significantly more breast-conserving surgery.

Antineoplastic Agents, Hormonal↗
PubMed2003

Controversial issues in ambulatory anesthesia.

Many controversies surround ambulatory anesthesia, but this article concentrates on two major areas: monitoring devices and airway management. Being able to monitor the depth of anesthesia has been a long-term goal with the aim of avoiding awareness during surgery. As monitoring devices are developed, they are being used to reduce anesthetic delivery and reduce costs, possibly increasing the risk of awareness. Management of the airway has been revolutionized by the laryngeal mask, and this article reviews some controversial uses. Several other airway devices that have been developed and promoted as suitable alternatives also are evaluated.

Ambulatory Surgical Procedures↗
PubMed2003

A new histological grading system to assess response of breast cancers to primary chemotherapy: prognostic significance and survival.

The clinical and complete pathological response of a primary breast cancer to chemotherapy has been shown to be an important prognostic for survival. However, the majority of patients do not experience a complete pathological response to primary chemotherapy and the significance of lesser degrees of histological response is uncertain and the prognostic significance is unknown. The purpose of this study was to evaluate a new histological grading system to assess response of breast cancers to primary chemotherapy and to determine if such a system has prognostic value.A consecutive series of 176 patients with large (> or =4cm) and locally advanced breast cancers were treated with multimodality therapy comprising primary chemotherapy, surgery, radiotherapy and tamoxifen. All underwent assessment of the primary breast tumour before and after completion of chemotherapy. Residual tumour was excised after completion of chemotherapy (mastectomy or wide local excision with axillary surgery). The removed tissue was assessed and response to chemotherapy graded using a five-point histological grading system based with the fundamental feature being a reduction in tumour cellularity; comparison being made with a pre-treatment core biopsy. All patients were followed up for 5 years or more. Pathological responses were compared to 5 year overall survival and disease-free survival using log rank tests. The overall 5-year survival for all patients was 71%, and 5 year disease free interval was 60%. There was a significant correlation between pathological response using this new grading system and both overall survival (P=0.02) and disease-free interval (P=0.04). In a multivariate analysis of known prognostic factors, the Miller/Payne grading system was an independent predictor of overall patient survival. This grading system, which assesses the histological response to primary chemotherapy, can predict overall survival and disease-free interval in patients with large and locally advanced breast cancers treated with such therapy. The relationship of degree of histological response to overall and disease-free survival has been shown in univariate and multivariate analyses and could potentially have an important role in the clinical management of patients with locally advanced breast cancer undergoing primary chemotherapy.

Adult↗
PubMed2003

Is there still a role for neoadjuvant therapy in breast cancer?

The role of neoadjuvant chemotherapy in locally advanced breast cancer is firmly established. There is now also an emerging role for neoadjuvant systemic therapy in the treatment of operable breast cancer. There is good evidence that the chances of breast conserving surgery can be increased with this approach and results of randomised studies indicate that survival is at least as good with neoadjuvant as with adjuvant chemotherapy. Similar clinical data are emerging with neoadjuvant endocrine therapy. For the future, there are important potential advantages in having an in vivo measure of chemosensitivity rather than blindly treating micrometastatic disease in the adjuvant setting. Clinical response to neoadjuvant treatment, and in particular complete pathological response, are predictors of subsequent outcome. Pathological involvement of axillary nodes following neoadjuvant therapy portends a poor prognosis. The potential for biological surrogate markers of response to predict for long-term outcome may allow individualisation of systemic treatment and the rapid assessment of new drugs in early breast cancer.

Antineoplastic Agents, Hormonal↗
PubMed2003

cDNAs encoding large venom proteins from the parasitoid wasp Pimpla hypochondriaca identified by random sequence analysis.

Venom from the parasitoid wasp Pimpla hypochondriaca contains numerous proteins, has potent in vitro anti-haemocytic properties, and disrupts host encapsulation responses. By sequencing 500 cDNAs randomly isolated from a venom gland library, we have identified 60 clones that encode proteins containing potential secretory signal sequences. To identify cDNAs encoding particular venom proteins, N-terminal amino acid sequences were determined for large (>30 kDa) venom proteins that had been separated using a combination of gel filtration and SDS-PAGE. We describe five of these cDNAs, which encoded residues that matched with the N-terminal sequences of previously undescribed venom proteins. cDNAs vpr1 and vpr3 encoded related proteins of approximately 32 kDa that were found in widely different fractions of gel filtration-separated venom. Neither vpr1 nor vpr3 were closely related to any other protein in the GenBank database, suggesting that they are highly specialised venom components. vpr2 encoded a 57-kDa polypeptide that was similar to a Drosophila protein, of unknown function, which lacks a signal sequence. A fourth clone, tre1, encoded a 61-kDa protein with extensive sequence similarity to trehalases. The 76-kDa sequence encoded by lac1 contained three regions which were very similar to histidine-rich copper-binding motifs, and could be aligned with the laccase from the fungus Coprinus cinereus. This study represents a significant step towards a holistic view of the molecular composition of a parasitoid wasp venom.

Amino Acid Sequence↗
PubMed2003

Doing more with less.

Explore the source record for details and available documents.

Ambulatory Surgical Procedures↗
PubMed2003

Total intravenous anaesthesia: is it worth the cost?

Total intravenous anaesthesia (TIVA) has many advocates and offers potential benefits, yet the direct costs of this technique are commonly greater than those of inhalation-based alternatives. Although many advantages are claimed for TIVA, in reality all modern anaesthetics are effective and have good safety and tolerability profiles, rendering these differences of less importance now than was perhaps once the case. The majority of direct comparisons between inhaled and intravenous anaesthetics have failed to demonstrate significant differences in recovery times, yet they have consistently shown greater direct costs associated with intravenous propofol anaesthesia. It is commonly believed that indirect costs may be offset by indirect savings achieved through more rapid recovery, reduction in adverse effects and decreased staff workloads. In some cases, these differences in outcome have not been observed, while in many where they have, indirect savings are only theoretical. Reductions in recovery time and nursing workload will only result in savings if fewer nurses are required or if the existing ones can be paid for fewer hours. Salary arrangements, peak demand for patient care, performance of multiple tasks in parallel and limitations in time accounting methodology all limit the ability to achieve such savings in reality. Drug wastage also contributes to the cost of anaesthesia and is common to both intravenous and inhaled techniques. With inhaled anaesthesia, wastage can be reduced by the use of lower fresh gas flows, which has no adverse consequences and may provide potential benefits. With intravenous anaesthesia, reducing drug wastage is difficult and potentially harmful through cross-contamination of drugs between patients. Recently, the cost of propofol has been reduced with the availability of generics, making TIVA a more attractive proposition. The costs of several inhaled anaesthetics have also decreased, however, reducing any relative benefit. Nevertheless, the net result of lowered costs is that all types of anaesthetic drugs, which typically comprise <5% of a hospital pharmacy budget, represent excellent value for money. With few new products in the immediate pipeline and most established drugs already generic or about to lose their patent protection, the expense of anaesthesia is likely to decline even further. Perhaps then we will be able to stop arguing over relatively small differences in cost and choose a technique that, in our own experienced hands, provides the best and safest patient outcomes.

Anesthesia↗
PubMed2003

In search of the good life: a cultural odyssey in the East and West.

In the first part of this article, the authors argue that any conception of well-being is culturally embedded and depends on how the notions of "well" and "being" are defined and practiced in different cultural communities. To support this argument, they conduct a comprehensive review of the empirical literature, which shows that members of individualistic and collectivistic cultures differ in their emotional experience of well-being. This difference has been traced to the indigenous psychology of selfhood in those cultures. In the second part of the article, the authors debunk the myth of infinite cultural variability, while retaining the basic insight concerning the cultural constitution of well-being. They develop a theoretical model of well-being, in which agency and communion are universal dimensions of well-being, and people in different cultures require different combinations of agency and communion to experience well-being. Following this theoretical development, the authors examine cultural impediments to the good life in individualistic and collectivistic cultures. The mutual incompatibility of agency and communion is ruled out as a possible cause of why it is so difficult to live the good life. Instead, the authors propose a dialectical synthesis of agency and communion as a way of dealing with this challenge of living the good life.

Affect↗
PubMed2002

Nurse led follow up and conventional medical follow up in management of patients with lung cancer: randomised trial.

OBJECTIVE: To assess the effectiveness of nurse led follow up in the management of patients with lung cancer. DESIGN: Randomised controlled trial. SETTING: Specialist cancer hospital and three cancer units in southeastern England. PARTICIPANTS: 203 patients with lung cancer who had completed their initial treatment and were expected to survive for at least 3 months. INTERVENTION: Nurse led follow up of outpatients compared with conventional medical follow up. OUTCOME MEASURES: Quality of life, patients' satisfaction, general practitioners' satisfaction, survival, symptom-free survival, progression-free survival, use of resources, and comparison of costs. RESULTS: Patient acceptability of nurse led follow up was high: 75% (203/271) of eligible patients consented to participate. Patients who received the intervention had less severe dyspnoea at 3 months (P=0.03) and had better scores for emotional functioning (P=0.03) and less peripheral neuropathy (P=0.05) at 12 months. Intervention group patients scored significantly better in most satisfaction subscales at 3, 6, and 12 months (P<0.01 for all subscales at 3 months). No significant differences in general practitioners' overall satisfaction were seen between the two groups. No differences were seen in survival or rates of objective progression, although nurses recorded progression of symptoms sooner than doctors (P=0.01). Intervention patients were more likely to die at home rather than in a hospital or hospice (P=0.04), attended fewer consultations with a hospital doctor during the first 3 months (P=0.004), had fewer radiographs during the first 6 months (P=0.04), and had more radiotherapy within the first 3 months (P=0.01). No other differences were seen between the two groups in terms of the use of resources. CONCLUSION: Nurse led follow up was acceptable to lung cancer patients and general practitioners and led to positive outcomes.

Aged↗
PubMed2002

Randomized, placebo-controlled trial of clodronate in patients with primary operable breast cancer.

PURPOSE: The development of bone metastases depends on tumor-induced osteoclastic resorption of bone, which may be inhibited by the antiosteolytic bisphosphonate clodronate. Given to patients with primary breast cancer, clodronate might reduce the subsequent incidence of bone metastases. PATIENTS AND METHODS: This double-blind, multicenter trial accrued 1,069 assessable patients with operable breast cancer between 1989 and 1995. All patients received surgery, radiotherapy, chemotherapy, and tamoxifen as required. Patients were randomized to receive oral clodronate 1,600 mg/d or a placebo for 2 years starting within 6 months of primary treatment. The primary end point was relapse in bone, analyzed on an intent-to-treat basis, during the medication period and during the total follow-up period (median follow-up, 2,007 days). Secondary end points were relapse in other sites, mortality, and toxicity. RESULTS: During the total follow-up period, there was a nonsignificant reduction in occurrence of bone metastases (clodronate, n = 63; placebo, n = 80; hazards ratio [HR], 0.77; 95% confidence interval [CI], 0.56 to 1.08; P =.127). During the medication period there was a significant reduction in the occurrence of bone metastases (clodronate, n = 12; placebo, n = 28; HR, 0.44; 95% CI, 0.22 to 0.86; P =.016). The occurrence of nonosseous metastases was similar (clodronate, n = 112; placebo, n = 128; P =.257), but there was a significant reduction in mortality (clodronate, n = 98; placebo, n = 129; P =.047) during the total follow-up period. CONCLUSION: Clodronate, given to patients with primary operable breast cancer, may reduce the occurrence of bone metastases, although this reduction was only significant during this medication period. There was a significant reduction in mortality.

Administration, Oral↗
PubMed2002

GTP cyclohydrolase I gene transfer augments intracellular tetrahydrobiopterin in human endothelial cells: effects on nitric oxide synthase activity, protein levels and dimerisation.

OBJECTIVES: Tetrahydrobiopterin (BH4) is an essential cofactor for endothelial nitric oxide synthase (eNOS) activity. BH4 levels are regulated by de novo biosynthesis; the rate-limiting enzyme is GTP cyclohydrolase I (GTPCH). BH4 activates and promotes homodimerisation of purified eNOS protein, but the intracellular mechanisms underlying BH4-mediated eNOS regulation in endothelial cells remain less clear. We aimed to investigate the role of BH4 levels in intracellular eNOS regulation, by targeting the BH4 synthetic pathway as a novel strategy to modulate intracellular BH4 levels. METHODS: We constructed a recombinant adenovirus, AdGCH, encoding human GTPCH. We infected human endothelial cells with AdGCH, investigated the changes in intracellular biopterin levels, and determined the effects on eNOS enzymatic activity, protein levels and dimerisation. RESULTS: GTPCH gene transfer in EAhy926 endothelial cells increased BH4 >10-fold compared with controls (cells alone or control adenovirus infection), and greatly enhanced NO production in a dose-dependent, eNOS-specific manner. We found that eNOS was principally monomeric in control cells, whereas GTPCH gene transfer resulted in a striking increase in eNOS homodimerisation. Furthermore, the total amounts of both native eNOS protein and a recombinant eNOS-GFP fusion protein were significantly increased following GTPCH gene transfer. CONCLUSIONS: These findings suggest that GTPCH gene transfer is a valid approach to increase BH4 levels in human endothelial cells, and provide new evidence for the relative importance of different mechanisms underlying BH4-mediated eNOS regulation in intact human endothelial cells. Additionally, these observations suggest that GTPCH may be a rational target to augment endothelial BH4 and normalise eNOS activity in endothelial dysfunction states.

3T3 Cells↗
PubMed2002

Lethal and sublethal effects of a granulovirus on the tomato moth Lacanobia oleracea.

A Scottish isolate of Lacanobia oleracea granulovirus (LoGV) was tested against larvae from a laboratory colony of L. oleracea (Lepidoptera: Noctuidae) using the peroral bioassay technique. The median lethal doses ranged from 10(1.38) occlusion bodies in first instar larvae to 10(7.45) in fifth instars. Sublethal effects on development and reproduction were observed among the survivors of virus challenge. Larvae dosed as first and second instars had faster developmental rates, and those dosed as fourth and sixth instars had reduced larval and pupal weights, compared to their respective controls. There was a 15% reduction in the number of eggs laid by adults that developed from infected larvae, but no reduction in egg viability. The F(1) generation did not show significantly greater mortality than controls, suggesting a lack of transovarial transmission. The significance of these results in terms of pest management of the tomato moth is discussed.

Animals↗