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Biomedical subjects

R Scott

Publications and source records attributed to R Scott.

At least 91 records · Page 5Linked to original sources
PubMed1998

Surface replacement hemiarthroplasty for the treatment of osteonecrosis of the femoral head.

We reviewed the results of thirty-three femoral resurfacing procedures in twenty-five patients who had stage-III or early stage-IV osteonecrosis of the femoral head according to the classification system of Ficat and Arlet. There were no perioperative complications. Thirty hip prostheses (91 percent) survived for a minimum of five years. At a mean of 10.5 years (range, four to fourteen years) postoperatively, sixteen (62 percent) of the twenty-six hips with stage-III disease had a good or excellent Harris hip score. Four of the seven hips with stage-IV disease did not have or need a total hip arthroplasty. Overall, twenty hips (61 percent) had a good or excellent result according to the scoring system of Harris, and thirteen (39 percent) had a fair or poor result and subsequently had or needed a total hip arthroplasty. The mean interval between the hemiarthroplasty and the total hip arthroplasty was sixty months (range, thirty-six to 136 months). These thirteen hips all had a successful clinical result (a Harris hip score of at least 80 points) at a mean of thirty months (range, twenty-four to seventy-two months) after the total hip arthroplasty. The results of the present study suggest that resurfacing of the femoral head can be a successful interim procedure for the management of patients who have Ficat and Arlet stage-III or early stage-IV disease with a large lesion that is not amenable to other treatment options except total hip arthroplasty.

Adult↗
PubMed1997

CT guided needle localization for video-thoracoscopic resection of pulmonary nodules.

Because of its decreased invasiveness Video-Assisted Thoracoscopic Surgery (VATS) has advantages over the traditional open thoracotomy. However, resection of small and subpleural pulmonary nodules via the thoracoscope is often technically difficult or impossible. To facilitate the resection of these difficult-to-palpate lesions, a protocol was established to localize the nodules percutaneously with a fine needle under CT guidance. This method was used in four patients to localize five lung lesions identified radiographically in various lung segments. Of the four patients in the study, three presented with malignancy of the lower extremities (alveolar sarcoma, squamous cell carcinoma, and spindle cell carcinoma). In two of these patients (having alveolar sarcoma and spindle cell carcinoma primaries), the resected pulmonary lesions proved to be metastatic disease. The lesions of the other two patients were nonmalignant (actinomycosis and fibrotic granuloma). The patients with actinomycosis had two distinct lesions which were identified preoperatively with two localizations. All five lesions were able to be localized and resected with clear margins. The patients tolerated the procedures well without complication. VATS with preoperative CT guided needle localization of a subpleural nodule can be a useful diagnostic tool. Its use in therapeutic metastasectomy, nonetheless, remains controversial.

Actinomycosis↗
PubMed1997

The Arabidopsis MALE STERILITY 2 protein shares similarity with reductases in elongation/condensation complexes.

The Arabidopsis thaliana MALE STERILITY 2 (MS2) gene product is involved in male gametogenesis. The first abnormalities in pollen development of ms2 mutants are seen at the stage in microsporogenesis when microspores are released from tetrads. Expression of the MS2 gene is observed in tapetum of wild-type flowers at, and shortly after, the release of microspores from tetrads. The MS2 promoter controls GUS expression at a comparable stage in the tapetum of transgenic tobacco containing an MS2 promoter-GUS fusion. The occasional pollen grains produced by mutant ms2 plants have very thin pollen walls. They are also sensitive to acetolysis treatment, which is a test for the presence of an exine layer. The MS2 gene product shows sequence similarity to a jojoba protein that converts wax fatty acids to fatty alcohols. A possible function of the MS2 protein as a fatty acyl reductase in the formation of pollen wall substances is discussed.

Amino Acid Sequence↗
PubMed1997

Lipid modifying agents: mechanisms of action and reduction of cardiovascular disease.

1. Recent studies (4S, CARE, WOSCOPS) with the HMG CoA reductase inhibitors have shown that reductions of total cholesterol and LDL cholesterol reduce the risk for a new fatal or non-fatal cardiac event by approximately 30-35%, providing LDL is decreased by 25-35%. 2. Preliminary data also suggest that achieved LDL levels around 3.2 mmol/L results in no greater reduction in new events than when LDL is lowered even further. 3. There is considerable debate, nonetheless, as to whether these reduction in cardiovascular events are entirely a consequence of LDL reduction or whether the lipid-modifying agents have effects on lipoprotein structure, endothelial cell function, clotting and haemorrheological pathways. 4. The study results achieved with statins have obscured the role of fibrates as useful agents for reducing cardiovascular disease. Fibrates have a different mode of action to stains by reducing triglyceride-rich lipoprotein precursors and favourably altering LDL and HDL composition. 5. The practising clinician needs to consider the lipoprotein phenotype and to choose whether the ideal treatment is stain alone, fibrate alone or perhaps a combination.

Anticholesteremic Agents↗
PubMed1997

Non-specialist management of tropical talipes.

Talipes equinovarus (clubfoot) is a complex deformity which in the West is usually treated by trained orthopaedic surgeons. In developing countries, however, most clubfeet will need to be treated by medical officers lacking specialist training. We report one author's experience in treating clubfeet in a small, rural East African hospital and review the literature in order to assist other non-specialists in managing this difficult condition in the face of poverty and poor parental compliance.

Casts, Surgical↗
PubMed1996

Increased expression of IL-1beta converting enzyme in hippocampus after ischemia: selective localization in microglia.

Although the interleukin-1beta converting enzyme (ICE)/CED-3 family of proteases has been implicated recently in neuronal cell death in vitro and in ovo, the role of specific genes belonging to this family in cell death in the nervous system remains unknown. To address this question, we examined the in vivo expression of one of these genes, Ice, after global forebrain ischemia in gerbils. Using RT-PCR and Western immunoblot techniques, we detected an increase in the mRNA and protein expression of ICE in hippocampus during a period of 4 d after ischemia. Chromatin condensation was observed in CA1 neurons within 2 d after ischemia. Internucleosomal DNA fragmentation and apoptotic bodies were observed between 3 and 4 d after ischemia, a period during which CA1 neuronal death is maximal. In nonischemic brains, ICE-like immunoreactivity was relatively low in CA1 pyramidal neurons but high in scattered hippocampal interneurons. After ischemia, ICE-like immunoreactivity was not altered in these neurons. ICE-like immunoreactivity, however, was observed in microglial cells in the regions adjacent to the CA1 layer as early as 2 d after ischemic insult. The increase in ICE-like immunoreactivity was robust at 4 d after ischemia, a period that correlates with the DNA fragmentation observed in hippocampal homogenates of ischemic brains. These results provide the first evidence for the localization and induction of ICE expression in vivo after ischemia and suggest an indirect role for ICE in ischemic damage through mediation of an inflammatory response.

Animals↗
PubMed1996

Dynamics of human replication protein A subunit distribution and partitioning in the cell cycle.

Human replication protein A (RPA) is a three-sub-unit protein complex involved in DNA replication, repair, and recombination. To gain insight into the dynamics of subunit assembly, we examined the subcellular distribution of RPA subunits (p70, p34, and p11) during the cell cycle. All three subunits colocalized in G1 and S phases, showing a diffuse nuclear distribution in G1 but a dot-like nuclear pattern in S phase. During S phase, the subunits showed a pattern reminiscent of the replication granules/factories described by others as sites of replication machinery. In meta-phase, p70 preferentially associated with the spindle poles, p34 was found on chromosomes, and p11 remained in the cytoplasm. In telophase, p70 and p34 appeared in the forming daughter nuclei; p11 remained in the cytoplasm until G1. Among the three subunits only p34 was associated with the nuclear matrix and this association persisted throughout the cell cycle. We conclude that (i) RPA complex assembly is differentially regulated, (ii) the replication machinery may be anchored to the nuclear matrix, and (iii) RPA subunits partition during mitosis and sort into daughter nuclei by different routes.

Cell Cycle↗
PubMed1996

Different patterns of cytokine induction in cultures of respiratory syncytial (RS) virus-specific human TH cell lines following stimulation with RS virus and RS virus proteins.

Human peripheral blood mononuclear cell (PBMC) proliferative responses to live respiratory syncytial (RS) virus, formalin-inactivated RS (Fl-RS) virus, RS virus F (fusion) protein, and RS virus G (attachment) protein were assessed. All donors responded to challenge with whole RS virus antigens and F and G proteins. F protein responses elicited higher levels of response than equivalent concentrations of G protein in nine out of ten adult RS-seropositive donors. Stimulation of PBMC induced low levels of interleukin 2 (IL-2), interferon gamma (IFN-gamma), IL-4, and IL-10 production. Human RS virus-specific T cell lines were generated from peripheral blood cultures following in vitro stimulation with RS virus antigens. All lines generated were shown to be MHC class II restricted. Characterisation of the lines was carried out by determining the levels of IL-2, IFN-gamma, IL-4, and IL-10 in culture supernatants. T cell lines enriched for RS virus-specific cells provided a more sensitive system than PBMC cultures for the detection of cytokines. The pattern of cytokine production varied for the individual lines, and the detection of TH1 and TH2 cytokines was dependent on the nature of the stimulating RS virus antigen. Live RS virus induced a TH1 pattern of cytokines (IL-2 and IFN-gamma), whereas FI-RS virus induced the production of both TH1 and TH2 cytokines. In addition, TH lines specific for individual RS virus proteins produced different cytokine profiles. F protein-specific lines generated TH1-type cytokines (IL-2 and IFN-gamma), whereas G protein-specific lines generated TH2-type cytokines (IL-4 and IL-10).

Adult↗
PubMed1996

Sensitivity of cell lines to mitomycin C.

OBJECTIVES: To determine the effect of pH on the cytotoxicity of mitomycin C on a wide range of established cell lines. MATERIALS AND METHODS: Cultures of three human tumour cell lines, including two bladder carcinomas and one renal adenocarcinoma, and two mouse cell lines were treated with mitomycin C (concentration range 320 pM-50 microM) at a range of pH (5.8-7.8) for 2 h. The cytotoxicity of mitomycin C over this range was determined using a tetrazolium-dye-based microtitration assay. RESULTS: The cytotoxicity of mitomycin C was significantly greater (confidence level > or = 95%) in acidic conditions (pH 5.8-6.0) than in neutral to alkaline pH (7.2-7.8) for three of the five cell lines. The same trend, although less marked, also occurred in the other two cell lines. CONCLUSION: The cytotoxicity of mitomycin C was greater under acidic conditions for all these cell lines confirming that the activity of mitomycin C depends on pH and suggesting that the pH of the vehicle used for intravesical chemotherapy may be an important factor in the successful treatment of bladder carcinomas. The modification of pH by urine may explain some of the variation in success rates among patients treated intravesically with mitomycin C.

Adenocarcinoma↗
PubMed1996

Overexpression of p53 protein and its significance for recurrent progressive bladder tumours.

OBJECTIVE: To determine the prognostic value of the overexpression of p53 protein as determined by immunohistochemistry in recurrent progressive transitional cell carcinomas of the bladder. PATIENTS AND METHODS: A total of 222 tumours from 86 patients with recurrent disease, 20 from patients with no evidence of recurrence after resection of initial tumour and 11 normal bladder (controls) were investigated. Using a microwave technique to expose antigens, formalin-fixed sections were immunohistochemically stained for p53 using a polyclonal antiserum. Two independent observers scored the sections for evidence of overexpression of p53. RESULTS: Of 86 patients with recurrent disease, 51 demonstrated overexpression of p53 protein, as did six of 20 patients with non-recurrent disease. Overexpression was not linked to recurrence (P = 0.5) but was related to worsening histological stage (P < 0.01) and increasing grade (P < 0.01). Regression analysis showed that overexpression of p53 for the primary tumour was not of predictive prognostic value for death from bladder cancer, time to progression or time to recurrence. Tumour grade was the only variable of prognostic value in all the statistical models. Patients with overexpression of p53 showed no reduction in overall survival. CONCLUSION: These findings suggest that overexpression of p53, as determined immunohistochemically, appears to have no predictive prognostic value over stage and grade in bladder tumours.

Aged↗