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Biomedical subjects

I Smith

Publications and source records attributed to I Smith.

At least 37 records · Page 2Linked to original sources
PubMed2002

Purification of pimplin, a paralytic heterodimeric polypeptide from venom of the parasitoid wasp Pimpla hypochondriaca, and cloning of the cDNA encoding one of the subunits.

We have previously detected a paralytic factor in gel filtration-separated venom from the endoparasitoid wasp Pimpla hypochondriaca which is active against the fly Musca domestica. Now we have further purified this factor, which we have called pimplin, by reverse phase chromatography, and established using SDS-PAGE that it has a molecular mass of approximately 22 kDa. A 40 ng dose of pimplin administered to adult M. domestica by intrahaemocoelic injection was sufficient to kill all flies tested. Treatment of pimplin with beta-mercaptoethanol prior to SDS-PAGE analysis resulted in the appearance of two polypeptides of approximately 15 and 6 kDa, indicating that pimplin is a heterodimer whose polypeptides are linked through a disulphide bond. Subunit masses of 10.544 and 6.318 kDa were determined using MALDI-TOF analysis indicating that the larger subunit migrates anomalously in SDS-PAGE. Using an oligonucleotide probe designed from N-terminal sequence obtained for the 15 kDa polypeptide, we have isolated a cDNA (pim1) encoding this larger pimplin subunit. The N-terminal amino acid sequence of pim1 occurred 28 residues beyond a predicted signal peptide cleavage site, indicating that pim1 is synthesised as a pre-propolypeptide which is secreted and proteolytically cleaved to yield the mature polypeptide stored in the venom sac. Beginning at the fourth residue of the mature pim1 venom polypeptide is a stretch of 46 residues consisting of alternating prolines, the significance of which is discussed in terms of possible host processing.

Amino Acid Sequence↗
PubMed2002

A skin sensitization safety assessment of a new bleach activator technology in detergent applications.

A new chemical called nonanoyl amido caproylacid oxybenzenesulphonate (NACAOBS) is being developed for use as a bleach activator in laundry detergents. Bleach activators, like NACAOBS, are typically used at levels between 2% and 6% in laundry detergents. NACAOBS is stable in aqueous solutions, but undergoes rapid perhydrolysis when combined with water and peroxygen bleach in laundry detergents. Animal testing demonstrated that NACAOBS, as a raw material, is a weak skin sensitizer. Clinical testing, including extended simulated laundry pretreatment, human repeat insult patch testing and home use testing was then undertaken, following sufficient reassurance of 1) the weak sensitization potential of the substance, 2) its rapid degradation in laundry wash solutions and, consequently, 3) low-to-negligible consumer dermal exposures to the native substance. Results confirmed the skin sensitization safety profile of laundry detergents containing NACAOBS, namely the absence of any reaction suggestive of contact sensitization (even under exaggerated dermal exposure conditions in a detergent matrix), and a skin compatibility profile comparable to that of current detergents. Further confirmation of the skin safety profile was obtained from a successful 12-month market test of a granular detergent containing 3.6% of the new substance, during which not a single adverse skin reaction was reported. In addition, NOBS (an oxybenzenesulphonate structural analogue to NACAOBS) has similar toxicological properties and has been safely marketed in detergents at similar levels for many years. It can be concluded that the likelihood of NACAOBS to induce skin sensitization or even elicit allergic reactions in consumer detergent use scenarios is negligible.

Animals↗
PubMed2002

A multi centre telephone survey of compliance with postoperative instructions.

Patients undergoing procedures under general anaesthesia as day cases are routinely given a set of instructions regarding activities to avoid in the first 24 h after discharge. Day surgery units generally specify the need for a responsible carer from time of discharge for a period of 24 h. This study looks at the compliance of 240 patients with postoperative instructions. Of the patients studied, 4.1% drove, 1.7% made important decisions, 3.3% drank alcohol, 0.8% took sedatives and 10% cooked, ironed or looked after children. All patients were discharged into the care of a responsible adult. However, 13.3% failed to have a carer with them for 24 h and 1.3% spent the night alone at home. Of our cohort, 25% were unable to comply with the postoperative instructions in full. The majority of non-compliance occurred on the day following surgery, suggesting that patients may feel that the advice is excessively cautious.

Activities of Daily Living↗
PubMed2002

Sevoflurane induction for emergency caesarean section: two case reports in women with needle phobia.

Needle phobia is an unusual but well-recognised clinical entity. It is claimed that it may affect up to 10% of the general population and may prevent potential patients from seeking medical care, thereby reducing its apparent incidence in the hospital population. Its occurrence in a parturient requiring urgent caesarean section presents special challenges to the anaesthetist. This report discusses the clinical, ethical and medico-legal dilemmas presented by two such cases that were successfully managed by inhalational induction of general anaesthesia using sevoflurane.

Journal Article↗
PubMed2002

The development and clinical use of trastuzumab (Herceptin).

HER-2 is a member of the c-erbB family of receptor tyrosine kinases and is overexpressed by 20-30% of human breast cancers. HER-2 overexpression is an independent adverse prognostic factor and may also predict for response to both chemotherapy and endocrine agents. Trastuzumab is a humanised monoclonal antibody that binds with high affinity to the extracellular domain of HER-2. In HER-2-overexpressing preclinical models trastuzumab has been shown to have a marked antiproliferative effect and demonstrates synergy with a number of cytotoxic drugs. Several phase II and phase III clinical trials have now been performed in patients with advanced breast cancer that overexpress HER-2. Trastuzumab was initially shown to be active and well tolerated as a single agent in heavily pretreated women. Subsequently, studies of first-line treatment for metastatic breast cancer have demonstrated an improvement in survival for trastuzumab when used in combination with either paclitaxel or an anthracycline-cyclophosphamide regimen compared with chemotherapy alone. Unexpectedly, the combination of trastuzumab and the anthracycline-containing regimen was associated with a significant incidence of cardiac dysfunction. The benefit of trastuzumab is generally confined to patients whose tumours have gene amplification as detected by fluorescence in situ hybridisation (FISH) and this is tightly associated with immunohistochemical (IHC) staining at the highest (3+) level. A small number of patients have IHC 2+ tumours together with FISH evidence of gene amplification and may also derive benefit from treatment. Trastuzumab has also been shown to be effective when used as first-line monotherapy for advanced breast cancer. Trials to date have employed trastuzumab in a weekly schedule, but there is emerging evidence that a three-weekly regimen may be as effective. Trastuzumab has shown encouraging activity when used with other agents including docetaxel and vinorelbine. The combination of trastuzumab, docetaxel, and platinum salts also appears to be very active. The role of trastuzumab as adjuvant therapy for early breast cancer is being tested in a number of large randomised trials.

Antibodies, Monoclonal↗
PubMed2001

HER-2 amplification impedes the antiproliferative effects of hormone therapy in estrogen receptor-positive primary breast cancer.

In experimental models, human epidermal growth factor receptor-2 (HER-2) amplification leads to estrogen independence and tamoxifen resistance in estrogen receptor (ER)-positive human breast cancer cells. Some but not all reports suggest an association between HER-2 positivity and hormone independence in breast cancer patients. This study aimed to evaluate the antiproliferative effects of endocrine therapy in HER-2-positive/ER-positive primary human breast cancer. The effect on proliferation (Ki67) of hormone therapy was assessed at 2 weeks and/or 12 weeks in biopsies from 115 primary breast cancers with ER-positive tumors. The patients took part in one of 3 neoadjuvant trials of hormonal therapy with a SERM (tamoxifen or idoxifene) or an aromatase inhibitor (anastrozole or vorozole). HER-2 status was assessed by immunocytochemistry and fluorescence in situ hybridization (FISH). Fifteen patients were defined as HER-2 positive by both immunohistochemistry and FISH, with the remaining 100 patients HER-2 negative. Geometric mean Ki67 levels were substantially higher in HER-2-positive than HER-2-negative tumors (27.7% versus 11.5%, respectively; P = 0.003). In HER-2-negative patients, Ki67 was reduced by 62 and 71% at 2 and 12 weeks, respectively (P < 0.0001 for both), but HER-2-positive patients showed no significant fall. The proportional change in Ki67 was significantly different between HER-2-positive and -negative patients (P = 0.014 at 2 weeks; P = 0.047 at 12 weeks). Mean ER levels were lower in the HER-2-positive patients (P = 0.06) but the change in Ki67 was impeded even in those with high ER. Apoptotic index was reduced by 30% at 2 weeks in the HER-2-negative group. However, there were no statistically significant differences in apoptotic index between the groups. It is concluded that ER-positive/HER-2-positive primary breast carcinomas show an impeded antiproliferative response to endocrine therapy that nonetheless may vary between individual treatments. This together with high baseline proliferation is likely to translate to poor clinical response.

Anastrozole↗
PubMed2001

Recurrent bacteremia and multifocal lower limb cellulitis due to Helicobacter-like organisms in a patient with X-linked hypogammaglobulinemia.

We describe a 27-year-old man with X-linked (Bruton's) hypogammaglobulinemia who presented during a 10-month period with recurrent fevers and multifocal lower-limb cellulitis associated with bacteremia due to Helicobacter-like organisms ("Flexispira rappini" and Helicobacter canis). Susceptible individuals may acquire infection of this type as a result of exposure to young dogs.

Adult↗
PubMed2001

Pan1b (17betaHSD11)-enzymatic activity and distribution in the lung.

We describe a new member of the 17beta-hydroxysteroid dehydrogenase group of enzymes. Human Pan1b displays greatest activity with 5alpha-androstan-3alpha,17beta-diol (3alpha-Diol) as substrate, suggesting that it may be important in androgen metabolism. Enzymic activity was non-saturable with 3alpha-Diol but saturable with retinoids, although retinoids were not metabolized. Immunohistochemical studies on 10% formalin fixed and paraffin embedded sections of human tissues showed that Pan1b was present in acini and ciliated epithelia of the lung. In the fetus immuno reactivity was present in ciliated epithelia throughout gestation and staining appeared to be stronger in the second half of pregnancy. Pan1b was also expressed in the nonpigmented epithelium of the ciliary body, and in adrenocortical tumor cells. Although 3alpha-Diol is generally considered a degradation product of androgen metabolism it could have its own biological function. Pan1b may be an important modulator of the endocrine, or intracrine activity of this steroid.

17-Hydroxysteroid Dehydrogenases↗
PubMed2001

Base excess and lactate as prognostic indicators for patients admitted to intensive care.

OBJECTIVE: To examine whether values of arterial base excess or lactate taken on admission to a general intensive care unit indicate prognosis, and whether this can be used as a screening tool for future intensive care admissions. DESIGN: Observational study. SETTING: University teaching hospital general adult intensive care unit. PATIENTS: 148 consecutive patients admitted to the intensive care unit. INTERVENTIONS: Arterial blood samples were obtained on admission to the intensive care unit and 24 h following admission. MEASUREMENTS AND RESULTS: Arterial base excess and lactate concentrations were measured from the blood samples. Both base excess and arterial lactate samples on admission have good prognostic abilities (area under the curve on receiver operator characteristic analysis of 0.73, 0.78, respectively). The value of base excess on admission with the best predictive ability was a base excess more negative than -4 mmol/l, and the corresponding value for lactate was greater than 1.5 mmol/l. The combination of these two markers on admission to the intensive care unit led to a sensitivity of 80.3 % and a specificity of 58.7 % for mortality. The achievement of this combination was associated with an increased mortality (50.6 % vs. 15 %, p < 0.0001), older age (70 vs. 61.5 years, p < 0.05), a greater requirement for inotropic support (30.9 % vs. 4.5%, p < 0.0001) and higher organ failure scores both on admission and for the subsequent 24 h. CONCLUSIONS: Both base excess and lactate, or the combination of the two, can be used to predict outcome in patients admitted to the intensive care unit. These variables could be utilized to identify patients who have a high risk for mortality and thus who should be admitted to the intensive care unit.

Acid-Base Equilibrium↗
PubMed2001

Anesthesia for laparoscopy with emphasis on outpatient laparoscopy.

Laparoscopy has developed extremely rapidly and is currently applicable to virtually every surgical subspecialty. Most of the experience is with gynecologic laparoscopy, which has been performed for many years. Some of these procedures are simple and brief, with minimal gas insufflation. In these cases, respiratory compromise is limited, and spontaneous ventilation appears acceptable. Such procedures therefore can be performed with the patient under local or regional anesthesia, or using the LMA with general anesthesia, because the risk of aspiration is small. As laparoscopy has developed, more prolonged operations have become possible, but these normally require general anesthesia, controlled ventilation, and tracheal intubation. More sophisticated laparoscopic surgery has reduced postoperative morbidity, shortened hospital stays, and moved many procedures into the outpatient arena. These newer laparoscopic operations present many challenges, especially in the provision of adequate analgesia and the minimization of PONV. Analgesia should be multimodal, using local anesthesia and NSAIDs as first-line therapy. This combination may be sufficient for more minor procedures, and the elimination of opioids helps to reduce PONV. For more extensive operations, opioids also are required, but should not be the mainstay of analgesia. PONV should be treated effectively whenever it occurs, with consideration given to the use of prophylactic antiemetics in especially high-risk groups. Laparoscopic surgery clearly offers significant advantages in many cases. Although this technology can make some procedures technically possible on an outpatient basis, the morbidity following operations such as laparoscopic cholecystectomy is considerable. The ever-greater cost savings from the expansion of outpatient surgery is being achieved at the expense of patient discomfort and dissatisfaction. Extended care (23 h) could be a better option in some circumstances. The future will see further developments in laparoscopic surgery. Microlaparoscopy permits simple procedures to be performed with minimal analgesia and sedation in an office setting. At present, this technology allows only diagnostic and minor operative procedures, the stage at which conventional laparoscopy was in the early 1980s. Further developments in optical fibers could reduce the requirements for general anesthesia for other operations and substantially reduce postoperative morbidity. Until then, laparoscopy continues to present many challenges.

Ambulatory Surgical Procedures↗
PubMed2001

A new form of arthropod phenoloxidase is abundant in venom of the parasitoid wasp Pimpla hypochondriaca.

We have recently identified phenoloxidase (PO) activity among several biologically active factors in venom from the parasitoid wasp Pimpla hypochondriaca. We have now isolated three genes, designated POI, POII and POIII, from a cDNA library made from venom-producing glands and found that their products are related to pro-phenoloxidases (PPOs), which are expressed as proenzymes in haemocytes and which mediate immune processes in arthropods. This is the first report of PO as a venom constituent. Amino acid sequence comparisons between the three Pimpla POs and PPOs revealed several notable differences, including the absence of sequences which specify the site of proteolytic activation in insect PPOs and the unprecedented occurrence of signal peptide sequences. NH(2)-terminal amino acid analysis of PO purified from venom yielded a peptide sequence matching the predicted mature NH(2) termini of POI and POII, confirming the authenticity of the signal peptide and indicating that proteolytic processing, other than to remove the signal peptide, does not occur in the wasp. Expression of POI, analysed by Northern hybridization, was approximately uniform from the time of adult emergence to day 6 post-emergence, after which it declined. A novel means of host immune suppression, mediated by the unregulated activity of venom PO in the haemocoel, is proposed.

Amino Acid Sequence↗
PubMed2001

The Mycobacterium tuberculosis ECF sigma factor sigmaE: role in global gene expression and survival in macrophages.

In previously published work, we identified three Mycobacterium tuberculosis sigma (sigma) factor genes responding to heat shock (sigB, sigE and sigH). Two of them (sigB and sigE) also responded to SDS exposure. As these responses to stress suggested that the sigma factors encoded by these genes could be involved in pathogenicity, we are studying their role in physiology and virulence. In this work, we characterize a sigE mutant of M. tuberculosis H37Rv. The sigE mutant strain was more sensitive than the wild-type strain to heat shock, SDS and various oxidative stresses. It was also defective in the ability to grow inside both human and murine unactivated macrophages and was more sensitive than the wild-type strain to the killing activity of activated murine macrophages. Using microarray technology and quantitative reverse transcription-polymerase chain reaction (RT-PCR), we started to define the sigmaE regulon of M. tuberculosis and its involvement in the global regulation of the stress induced by SDS. We showed the requirement for a functional sigE gene for full expression of sigB and for its induction after SDS exposure but not after heat shock. We also identified several genes that are no longer induced when sigmaE is absent. These genes encode proteins belonging to different classes including transcriptional regulators, enzymes involved in fatty acid degradation and classical heat shock proteins.

Animals↗
PubMed2001

The Mycobacterium tuberculosis IdeR is a dual functional regulator that controls transcription of genes involved in iron acquisition, iron storage and survival in macrophages.

In this work, we characterize genes in Mycobacterium tuberculosis that are regulated by IdeR (iron-dependent regulator), an iron-responsive DNA-binding protein of the DtxR family that has been shown to regulate iron acquisition in Mycobacterium smegmatis. To identify some of the genes that constitute the IdeR regulon, we searched the M. tuberculosis genome for promoter regions containing the consensus IdeR/DxR binding sequence. Genes preceded by IdeR boxes included a set encoding proteins necessary for iron acquisition, such as the biosynthesis of siderophores (mbtA, mbtB, mbtI), aromatic amino acids (pheA, hisE, hisB-like) and others annotated to be involved in the synthesis of iron-storage proteins (bfrA, bfrB). Some putative IdeR-regulated genes identified in this search encoded proteins predicted to be engaged in the biosynthesis of lipopolysaccharide (LPS)-like molecules (rv3402c), lipids (acpP) and peptidoglycan (murB). We analysed four promoter regions containing putative IdeR boxes, mbtA-mbtB, mbI, rv3402c and bfrA-bfd, for interaction with IdeR and for iron-dependent expression. Gel retardation experiments and DNase footprinting analyses with purified IdeR showed that IdeR binds to these IdeR boxes in vitro. Analysis of the promoters by primer extension indicated that the IdeR boxes are located near the -10 position of each promoter, suggesting that IdeR acts as a transcriptional repressor by blocking RNA polymerase binding. Using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) coupled to molecular beacons, we showed that mRNA levels of mbtA, mbtB, mbtI, rv3402c and bfd are induced 14- to 49-fold in cultures of M. tuberculosis starved for iron, whereas mRNA levels of bfrA decreased about threefold. We present evidence that IdeR not only acts as a transcriptional repressor but also functions as an activator of bfrA. Three of the IdeR- and iron-repressed genes, mbtB, mbtI and rv3402c, were induced during M. tuberculosis infection of human THP-1 macrophages.

Bacterial Proteins↗
PubMed2001

Future directions in the adjuvant treatment of breast cancer: the role of trastuzumab.

Current evidence shows that adjuvant cytotoxic or hormonal therapy increases the disease-free and overall survival of patients. The analysis by the Early Breast Cancer Trialists' Collaborative Group (EBCTCG) showed that anthracycline/cyclophosphamide (AC)-containing regimens are more effective than those without AC, providing an 11% greater reduction in the risk of death compared with non-AC-containing regimens. In addition, paclitaxel and docetaxel have significant anti-tumor activity in previously treated patients and sequential treatment with paclitaxel may further reduce the risk of recurrence and improve survival. Tamoxifen is effective in reducing the risk of recurrence and death in patients with estrogen receptor (ER)-positive tumors. The addition of tamoxifen to combination chemotherapy in patients with ER-positive tumors further reduces the risk of recurrence and improves survival. Debate on the effectiveness of tamoxifen in HER2-positive patients is currently underway. A number of trials are in progress or planned to investigate the use of the anti-HER2 monoclonal antibody trastuzumab (Herceptin) in the adjuvant setting. These include a National Surgical Adjuvant Breast and Bowel Project (NSABP) adjuvant trial (AC --> paclitaxel vs. AC --> paclitaxel + trastuzumab) and an Intergroup study (AC --> paclitaxel vs. AC --> paclitaxel + trastuzumab vs. AC --> paclitaxel --> trastuzumab). Results from these trials will determine whether this novel therapy has a survival benefit in early breast cancer.

Antibiotics, Antineoplastic↗
PubMed2001

Prophylactic ondansetron does not improve patient satisfaction in women using PCA after Caesarean section.

Eighty-one consenting women undergoing elective Caesarean section under spinal anaesthesia were randomly divided into two groups. In Group O patients, ondansetron 4 mg was given intravenously at the end of the surgery and 8 mg added to the morphine solution in the PCA syringe. Patients in Group P received only morphine via PCA syringe. Analgesia and nausea were measured until PCA was discontinued 24 h after the operation. Women in the two groups were similar with respect to age, duration of use of the PCA, amount of morphine used, previous history of PONV, and incidence of motion sickness and morning sickness during the current pregnancy. The number of women who complained of nausea and those needing rescue antiemetic medication was significantly less in Group O. However, there was no statistically significant difference between the two groups in the patient's perception of the control of nausea and their overall satisfaction. It was noted that PONV was more frequent among women who had significant morning sickness during early pregnancy and ondansetron was beneficial in reducing PONV in these women. Although the ondansetron reduced the incidence of PONV and the need for further antiemetic medication, this did not affect patient's satisfaction regarding their postoperative care.

Analgesia, Patient-Controlled↗