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Biomedical subjects

A R Smith

Publications and source records attributed to A R Smith.

At least 37 records · Page 2Linked to original sources
PubMed2000

The effect of ethylene on MAPKinase-like activity in Arabidopsis thaliana.

Protein kinase activity was studied in cytosolic extracts from leaves of wild type Arabidopsis thaliana, the ethylene-insensitive mutant, etr1, and the constitutive triple-response mutant, ctr1. Treatment of wild type with ethylene resulted in increased myelin basic protein (MBP) phosphorylation. In etr1, constitutive protein kinase activity was lower than in wild type, but in ctr1, activity was enhanced. A protein of M(r) approximately 47 kDa associated with MBP-phosphorylating activity was detected using in gel protein kinase assays and phosphorylation of this protein was promoted by ethylene treatment in wild type while activity in the mutants reflected that of MBP phosphorylation. Both MAPKinase (ERK 1) and phosphotyrosine antibodies immunoprecipitated MBP-phosphorylating activity and detected a polypeptide band at M(r) approximately 47 kDa. Immunoprecipitated MBP-phosphorylating activity was again much lower in etr1 compared to wild type but much higher in ctr1. Antibodies to phosphorylated MAPKinase recognised proteins at approximately 47 kDa and the signal was upregulated in response to ethylene. The data obtained suggest that the detected protein(s) is a MAPKinase and provide further evidence confirming that a MAPKinase cascade(s) is involved in ethylene signal transduction.

Arabidopsis↗
PubMed2000

Separation of the enzyme cofactor pyrroloquinoline quinone and three isomeric analogues by capillary electrophoresis with ion-pairing media.

The enzyme cofactor pyrroloquinoline quinone (PQQ) was successfully separated from three closely related isomeric analogues by capillary electrophoresis with ultraviolet detection. Rapid and efficient separation of all four negatively charged isomers with baseline resolution was achieved by the addition of low concentrations (1-5 mM) of short chain tetraalkylammonium (TAA) salts to the capillary buffer. The TAA cations act as ion-pairing agents and promote differential migration of the isomers with only a minimal reduction in the electroosmotic flow. The effects of the TAA salt concentration and the alkyl chain length were examined. Detection limits of PQQ and its isomers were in the range of 7-15 microM with mass detection limits of 98-210 fmol.

Chromatography, High Pressure Liquid↗
PubMed2000

Fine-needle aspiration cytology of unsuspected metastatic thyroid carcinoma initially presenting in bone: report of three cases and a review of the literature.

We present a series of three cases of unsuspected thyroid carcinoma presenting as bony lesions and initially studied by fine-needle aspiration (FNA). This series consists of two cases of follicular carcinoma and a third case of Hurthle cell carcinoma. FNA was performed on all three lesions. In two of these cases, a definitive diagnosis of metastatic thyroid carcinoma was made based on the FNA material. FNA smears of both follicular carcinomas displayed cohesive clusters of atypical round cells with nuclear overlapping and positive immunoperoxidase staining for thyroglobulin. The aspirates of the Hurthle cell carcinoma were composed of sheets and individually scattered oval oncocytic cells with prominent nucleoli. All three cases demonstrated the presence of marginal vacuoles consistent with "flame" cells. To the best of our knowledge, this is the first series discussing the cytologic features and differential diagnosis of unsuspected thyroid carcinoma initially presenting as metastatic bone lesions.

Biopsy, Needle↗
PubMed2000

An evaluation of the efficacy of in-patient bladder retraining.

This is a retrospective review of 50 consecutive patients with urinary frequency, urgency and urge incontinence, admitted in 1995 and early 1996 for bladder retraining in the form of timed voiding. At discharge 80% of the women were subjectively cured or satisfactorily improved, but this was significantly reduced to 32% of the 37 who replied to a postal survey between 12 and 29 months (mean interval 21.3 months) later. There were no significant associations between outcome and urodynamic diagnosis, reduced cystometric capacity, length of symptomatology, previous treatment or requirement for additional therapy, but this may have been in part due to small numbers. In conclusion, bladder retraining is a method of treatment for patients with both sensory urgency and detrusor instability which appears to be at least as successful as other modes of treatment for these conditions.

Female↗
PubMed2000

Post-operative complications following minimal access surgery.

The growth in popularity of minimal access surgery in gynaecology has coincided with a reduction in the length of hospital stay. Patients need to be made aware of the potential for and symptoms and signs of complications to ensure that they seek help at an early stage. Clinicians need to be vigilant in the recognition of adverse events both intra- and post-operatively to minimize the risk of developing serious complications. The growth in litigation in minimal access surgery represents, in part, a failure of surgeons to adapt to the new demands of this type of surgery.

Female↗
PubMed2000

Current trends in defibrillator development.

With the recent release of the National Service Framework (NSF) for Coronary Artery Disease, this article looks at defibrillator availability and training for acute- and primary-care providers. Well-equipped services (including ward areas, GP surgeries and ambulances) and personnel with appropriate skills in defibrillation are the key to the NSF for management of acute myocardial infarction.

Electric Countershock↗
PubMed1999

Intraoperative cytologic diagnosis of suprasellar and sellar cystic lesions.

The intraoperative distinction of craniopharyngiomas (CP) and cystic pituitary adenomas (PA) from other intracranial parasellar cystic lesions can significantly modify the extent of surgery and reduce postoperative morbidity. Frozen-section diagnosis may be limited by the scant tissue available for examination. The imprint cytology of six parasellar cystic lesions is examined, along with their radiologic and histologic findings. These include two Rathke's cleft cysts (RCC), three CP, and one cystic PA. RCC showed scattered clusters of cuboidal cells with prominent cilia. Cystic PA demonstrated clusters of monomorphic round cells with minimal cytoplasm. CP displayed "wet" keratin and clusters of squamous cells with a palisaded border. In all six cases, cytology supported the final histologic diagnosis. In one case, the intraoperative diagnosis was based solely on cytologic examination. Cytology can contribute significantly to an accurate intraoperative diagnosis of parasellar cystic lesions and potentially modify surgical management.

Adenoma↗
PubMed1999

Fine-needle aspiration cytologic features of pseudovascular adenoid squamous-cell carcinoma of the lung.

Pseudovascular adenoid squamous-cell carcinoma (PASCC) is an epithelial malignancy with spindle-cell features that can mimic vascular neoplasms, particularly angiosarcoma, in its morphologic characteristics. There have been only a few surgical pathology reports of PASCC arising in the lung, skin, and breast. We describe the fine-needle aspiration (FNA) cytologic and histologic features of a pulmonary PASCC in a 66-yr-old man. The aspiration yielded individually scattered and syncytial fragments of malignant epithelioid-appearing cells with oval to spindle shapes, prominent nucleoli, and a finely vacuolated amphophilic cytoplasm. The core needle biopsy specimen displayed these same cells lining pseudoluminal spaces, with intervening bundles of fibroconnective tissue simulating a vascular neoplasm. The neoplastic cells stained positively with cytokeratin (AE-1/3), epithelial membrane antigen, and vimentin and were nonreactive with S-100, muscle-specific actin, CD31, CD34, and carcinoembryonic antigen. These cytologic, histologic, and immunocytochemical features supported a diagnosis of PASCC. To the best of our knowledge, this is the first report of the FNA cytologic features of this pseudovascular variant of adenoid squamous-cell carcinoma. This FNA case illustrates that the cytologic impression was more accurate and, in fact, that the histologic features of PASCC can be misleading. The correct identification of PASCC and its distinction from angiosarcoma has important clinical ramifications for treatment and prognosis. FNA cytologic examination with ancillary studies is a minimally invasive procedure that can distinguish PASCC from sarcomatous lesions. Diagn. Cytopathol. 1999;21:265-270.

Aged↗
PubMed1999

The effect of ethylene and cytokinin on guanosine 5'-triphosphate binding and protein phosphorylation in leaves of Arabidopsis thaliana.

Binding of [alpha-32P]guanosine 5'-triphosphate ([alpha-32P]GTP) has been demonstrated in a Triton X-100-solubilised membrane fraction from leaves of Arabidopsis thaliana (L.) Heynh. Binding was stimulated by 1 h pre-treatment of leaves with ethylene and this effect was antagonised by the inclusion of N6-benzyladenine in the medium used for homogenisation. The ethylene-insensitive mutants eti 5 and etr showed contrasting responses. In eti 5 the constitutive level of GTP binding was higher than in the wild type whereas in etr the level was much lower. Neither ethylene nor cytokinin affected GTP binding in the mutants. The GTP-binding activity was localised in two bands at 22 and 25 kDa, both of which were immunoprecipitated by anti-pan-Ras antibodies, indicating that the activity is due to small GTP-binding proteins. In a similar membrane fraction, ethylene was shown to increase protein phosphorylation and benzyladenine antagonised this effect. In eti 5 the constitutive level of protein phosphorylation was higher than in the wild type, but benzyladenine increased activity substantially while ethylene was without effect. In etr, protein phosphorylation was lower than in the wild type, ethylene was without effect, but cytokinin increased activity. A protein of M(r) 17 kDa was detected on gels using antibodies to nucleoside diphosphate kinase. Phosphorylation of this protein was upregulated by ethylene but nucleoside diphosphate kinase activity was unaffected. The results are compared with the effect of the two hormones on the senescence of detached leaves and discussed in relation to pathways proposed for ethylene signal transduction.

Adenine↗
PubMed1999

Laparoscopic colposuspension.

Laparoscopic Burch colposuspension has entered the surgical armory for the treatment of genuine stress incontinence. The limited data available of the outcomes of the procedure currently suggest that success rates are lower than for the open colposuspension in the short term. Data is lacking on long-term effectiveness. This and the longer operating times documented may reflect inexperience of surgeons. There seem to be advantages in terms of sooner return to normal voiding, earlier discharge from hospital, perioperative morbidity, and a lower incidence of voiding problems when compared with the open procedure. No reduction in the incidence of de novo detrusor instability postoperatively has emerged. A large randomized controlled trial of the two procedures is required to provide higher quality data on outcomes.

Cervix Uteri↗
PubMed1999

The suspiciousness factor: critical care nursing and forensics.

This conceptual article provides a guide for understanding the place of forensic nursing within the discipline of nursing. Ways of knowing in nursing and expert nursing practice are described to identify the role of intuition in nursing practice. The relationship between suspicion and intuition is explored. Strategies for developing forensic nursing expertise and increasing suspicion are described. Suspicion (intuition) is presented as a rapid, acquired, patient oriented perception that leads to decisive action.

Clinical Competence↗
PubMed1999

The clinical, histologic, and ultrastructural presentation of polyvinyl sponge (Ivalon) breast prostheses removed for massive fluid accumulation.

The current study describes what we believe is the first report of bilateral massive seromas associated with open-cell Ivalon sponges. Additionally, the gross, histologic, and ultrastructural features consistent with previous reports of polyvinyl alcohol prostheses are presented. Despite the reported chemical inertness of polyvinyl alcohol, this material may incite a biologic response in some patients, leading to dense fibrosis and occasional foreign-body giant-cell reaction. It is postulated that the molecular breakdown products of the polyvinyl alcohol polymer may create an osmotic gradient across the periprosthetic capsule, which may lead to intracapsular fluid accumulation, as presented in this case.

Aged↗
PubMed1998

Temporal lobe (TL) damage following surgery and high-dose photon and proton irradiation in 96 patients affected by chordomas and chondrosarcomas of the base of the skull.

PURPOSE: To determine the temporal lobe (TL) damage rate in 96 patients treated with high-dose proton and photon irradiation for chordomas and chondrosarcomas of the base of the skull. METHODS AND MATERIALS: The records of 96 consecutive patients treated at Massachusetts General Hospital (MGH) and Harvard Cyclotron Laboratory (HCL) between June 1984 and 1993, for chordomas and chondrosarcomas of the base of the skull were reviewed. All the patients had undergone some degree of resection of the tumor prior to radiation therapy. Seventy-five patients were classified as "primary tumors" and 21 as recurrent or regrowing tumors after one or more surgical procedures. All the patients were randomized to receive 66.6 or 72 cobalt Gray equivalent (CGE) on a prospective dose-searching study by proton and photon irradiation (Radiation Therapy Oncology Group #85-26) with conventional fractionation (1.8 CGE/day, 5 fractions/week). All treatments were planned using the three-dimensional (3D) planning system developed at the Massachusetts General Hospital, and the dose was delivered using opposed lateral fields for the photon component and a noncoplanar isocentric technique for the proton component. Clinical symptoms of TL damage were classified into 4 grades. Computerized tomography (CT) and magnetic resonance imaging (MRI) scans were evaluated for white matter changes. Abnormalities associated with persistent or recurrent tumor were distinguished from radiation-induced changes. TLs were delineated on the original scans of the 10 patients with damage and those of a group of 33 patients with no clinical or MRI evidence of injury. Dose distributions were calculated and dose-volume histograms were obtained for these patients. RESULTS: Of the patients, 10 developed TL damage, with bilateral injury in 2 and unilateral injury in 8. The cumulative TL damage incidence at 2 and 5 years was 7.6 and 13.2%, respectively. The MRI areas suggestive of TL damage were always separated from the tumor bed. Symptoms were severe to moderate in 8 patients. Several baseline factors, tumor- or host-related, were analyzed to evaluate their predictivity for TL damage: age, gender, tumor site, histology, type of presentation, type and number of surgical procedures, primary tumor volume, prescribed dose, normal tissue involvement, and volume of TL receiving doses ranging between 10 and 50 CGE or more. Only gender, in a univariate analysis (log rank) was a significant predictor of damage (0.0155), with male patients being at significantly higher risk of TL injury. In a stepwise Cox regression that included gender as a variable, no other baseline variable improved the prediction of damage. CONCLUSIONS: The 2- and 5-year cumulative TL damage rates were 7.6 and 13.2%, respectively. Despite the different TL damage rates related to age, tumor volume, number of surgical procedures prior to radiation therapy, and prescribed doses to the tumor, only gender was a significant predictor of damage (p = 0.0155) using a univariate (log rank) test. Chordomas and chondrosarcomas of the base of the skull may represent an interesting model to evaluate the TL damage rates because of their extradural origin, displacing the white matter instead of infiltrating it as gliomas do, because of their longer local recurrence-free survival other than gliomas and other brain tumors and because of the high doses of irradiation delivered to the target volume to obtain local control.

Adolescent↗
PubMed1998

A novel plasmid pIJB1 possessing a putative 2,4-dichlorophenoxyacetate degradative transposon Tn5530 in Burkholderia cepacia strain 2a.

A 102-kb plasmid, pIJB1, was isolated from Burkholderia cepacia strain 2a, which is able to use 2,4-dichlorophenoxyacetate (2,4-D) as a sole carbon source, and a physical map of the plasmid has been established. It was observed that spontaneous loss of a 37-kb fragment of the plasmid after growth in nonselective medium occurred, generating a plasmid of diminished size, pIJB2. The deletion event is concomitant with the loss of the 2,4-D dissimilatory phenotype, indicating that at least some of the 2,4-D degradative genes are on the missing fragment. The missing fragment is flanked by two identical 4.3-kb insertion sequences (IS) and shows a typical composite transposon structure of 41-kb in size, designated Tn5530. The mutant plasmid pIJB2 possesses a single copy of the IS element.

2,4-Dichlorophenoxyacetic Acid↗