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Biomedical subjects

S Martin

Publications and source records attributed to S Martin.

At least 307 records · Page 17Linked to original sources
PubMed1997

Preoperative recombinant human erythropoietin injection versus preoperative autologous blood donation in patients undergoing radical retropubic prostatectomy.

OBJECTIVES: In an effort to avoid allogeneic transfusions, many patients scheduled for radical retropubic prostatectomy (RRP) participate in preoperative autologous donation (PAD) programs. Yet, PAD programs are costly, time-consuming, and not without risks. Perioperative administration of recombinant human erythropoietin (Epoetin alfa) also has been shown to reduce patients exposure to allogeneic transfusion. This study sought to compare the costs and transfusion rates associated with either PAD or perioperative Epoetin alfa in patients undergoing RRP. METHODS: The study population consisted of 120 men randomized to one of two treatment groups. Patients in group 1 donated up to 3 U of autologous blood preoperatively, provided that their hematocrit (HCT) was 33% or higher. Patients in group 2 received 600 IU/kg of Epoetin alfa on days -14 and -7 preoperatively, provided that their HCT was 46% or lower. RESULTS: Overall, 107 (89%) of 120 patients underwent RRP. In group 1, 5 (9.6%) of 52 patients received a total of 12 U of allogeneic blood (0.23 U/patient). In group 2, 5 (9.6%) of 52 patients received a total of 10 U of allogeneic blood (0.19 U/patient). Three patients in group 1 but no patients in group 2 experienced an adverse event. The average costs related to PAD and pharmacologic administration per patient were $540 in group 1 and $657 in group 2. Participation in PAD required an average of 5 hours more per patient compared with Epoetin alfa administration. CONCLUSIONS: Preoperative Epoetin alfa therapy is safe, well tolerated, and equally effective as PAD in reducing allogeneic blood transfusion requirements. Epoetin alfa therapy also is comparable in cost to PAD and offers patients greater convenience and less of a time commitment.

Aged↗
PubMed1997

Short communication: cultivation of bloodstream forms of Trypanosoma brucei and T. evansi in a serum-free medium.

Bloodstream forms of Trypanosoma brucei and T. evansi have been cultivated in an axenic culture system by using Iscove's modified DMEM-based HMI-9 medium supplemental with bathocuproinedisulphonic acid, L-cysteine, hypoxanthine, 2-mercaptoethanol, pyruvate, thymidine and 10% fetal bovine or adult horse serum. We developed a serum-free medium (HMI-244) in which serum in HMI-9 was replaced by fatty acid-free bovine serum albumin, bovine alpha 2-macroglobulin, bovine beta-lipoprotein, d-biotin, retinol, beta-alanine, L-anserine nitrate salt, L-ornithine hydrochloride, O-phosphorylethanolamine, sarcosine, taurine, adenosine-5'-triphosphate, 2'-deoxycytidine-5'-monophosphate, 2'-deoxyguanosine-5'-monophosphate, and 5-methyltetrahydrofolic acid. Maximum cell densities and population doubling times were 2.6 x 10(6) cells/ml; 10.6 hours and 2.2 x 10(6) cells/ml; 10.9 hours for T. brucei and T. evansi, respectively. Bloodstream forms continued to proliferate in the serum-free cultures for more than 90 days and the trypomastigotes retained their morphological characteristics and infectivity to mice. If validated, this serum-free medium may help reduce future interlaboratory variability in biochemical, immunological, molecular biological and drug sensitivity studies on these parasites.

Animals↗
PubMed1997

Soluble adhesion molecules in type 1 diabetes mellitus.

Adhesion molecules play an important role during leukocyte emgration from blood vessels. Furthermore, adhesion molecules are involved in the regulation of the immune system. In addition to membrane-bound adhesion molecules soluble forms have been detected in human serum. During the last few years we have analysed the role of adhesion molecules during the pathogenesis of type 1 diabetes. This review describes the results of studies on membrane-bound and soluble adhesion molecules in humans and the model of the NOD mouse. Based on these results different adhesion molecule-specific immunotherapies are presented for the prevention of type 1 diabetes and its preclinical stages.

Animals↗
PubMed1997

Program evaluation of a unit reengineered for patient-focused care.

A quasi-experimental research design was used to determine how successful a work redesign project based on the philosophy of patient-focused care was in meeting the established goals of increased multidisciplinary collaboration, improved satisfaction for health care clients and providers, decreased cost of care, and decreased length of stay. Results indicate that multidisciplinary collaboration decreased for all health care providers, especially the health care employee group that underwent a major role revision. Patient and health care provider satisfaction increased. The cost of care was budget neutral as a result of the shift of employee costs from centralized departments to units. Length of stay decreased.

Adolescent↗
PubMed1997

Synthesis, biological activity and isomerism of guanylate cyclase C-activating peptides guanylin and uroguanylin.

Recently, the peptides guanylin and uroguanylin were identified as endogenous ligands of the membrane-bound guanylate cyclase C (GC-C) that is mainly expressed in the intestinal epithelium. In the present study, bioactive guanylin and uroguanylin have been prepared by solid-phase methodology using Fmoc/HBTU chemistry. The two disulfide bonds with relative 1/3 and 2/4 connectivity have been introduced selectively by air oxidation of thiol groups and iodine treatment of Cys(Acm) residues. Using this strategy, several sequential derivatives were prepared. Temperature-dependent HPLC characterization of the bioactive products revealed that guanylin-related peptides exist as a mixture of two compounds. The isoforms are interconverted within approximately 90 min, which prevents their separate characterization. This effect was not detected for uroguanylin-like peptides. Synthetic peptides were tested for their potential to activate GC-C in cultured human colon carcinoma cells (T84), known to express high levels of GC-C. The results obtained show that both disulfide bonds are necessary for GC-C activation. The presence of the amino-terminally neighboring residues of Cys104 for guanylin and Cys100 for uroguanylin has been found to be essential for GC-C stimulation. Unexpectedly, a hybrid peptide obtained from substitution of the central tripeptide AYA of guanylin by the tripeptide VNV of uroguanylin was not bioactive.

Amino Acid Sequence↗
PubMed1997

Expression cloning and humoral immune response to the nucleocapsid and membrane proteins of equine arteritis virus.

To provide a convenient and sensitive method for the detection of equine arteritis virus (EAV)-specific serum antibodies, we developed an immunoblot assay employing the EAV nucleocapsid (N) and membrane (M) proteins expressed in a procaryotic expression vector (pMAL-c2) for the production of recombinant maltose-binding (MBP) fusion proteins (MBP-N and MBP-M). The antigenic reactivity of the recombinant fusion proteins and their Xa factor cleavage EAV products was confirmed by immunoblot using horse antisera to EAV. Some horse sera, however, showed immune reactivity to the MBP fusion partner protein. Based on a total of 32 horse sera analyzed for the presence of EAV antibodies by immunoblot, using the MBP-N or -M fusion proteins and the Xa factor cleavage EAV products, and in the serum neutralization test, there was 100% concordance between the assays. Sera from horses experimentally infected with EAV were reactive in the immunoblot test with both the MBP-N and the MBP-M fusion proteins by day 14 after EAV exposure. The reactivity continued to the end of the experiment at day 145 after infection. This immune reactivity correlated with the detection of neutralizing antibodies in the serum samples. Based on these findings, the recombinant N and M proteins might be useful for serodetection of EAV-infected animals.

ATP-Binding Cassette Transporters↗
PubMed1997

The glucose transporter GLUT4 and the aminopeptidase vp165 colocalise in tubulo-vesicular elements in adipocytes and cardiomyocytes.

The aminopeptidase vp165 is one of the major polypeptides enriched in GLUT4-containing vesicles immuno-isolated from adipocytes. In the present study we have confirmed and quantified the high degree of colocalisation between GLUT4 and vp165 using double label immuno-electron microscopy on vesicles isolated from adipocytes and heart. The percentage of vp165-containing vesicles that also contained GLUT4 was 91%, 76%, and 86% in rat adipocytes, 3T3-L1 adipocytes, and rat heart, respectively. Internalisation of a transferrin/HRP (Tf/HRP) conjugate by 3T3-L1 adipocytes, followed by diaminobenzidine treatment in intact cells, resulted in ablation of only 41% and 45% of GLUT4 and vp165, respectively, whereas endosomal markers are almost quantitatively ablated. Using immuno-electron microscopy on cryosections it was determined that in atrial cardiomyocytes GLUT4 and vp165 colocalised in a population of tubulo-vesicular (T-V) elements that were often found close to the plasma membrane. Double label immunocytochemistry indicated a high degree of overlap in these T-V elements between GLUT4 and vp165. However, in atrial cardiomyocytes a large proportion of GLUT4 was also present in secretory granules containing atrial natriuretic factor (ANF). In contrast, very little vp165 was detected in ANF granules. These data indicate that GLUT4 and vp165 are colocalised in an intracellular, post-endocytic, tubulo-vesicular compartment in adipocytes and cardiomyocytes suggesting that both proteins are sorted in a similar manner in these cells. However, GLUT4 but not vp165 is additionally localised in the regulated secretory pathway in atrial cardiomyocytes.

3T3 Cells↗
PubMed1997

Play and learn team building.

In order to have a team function correctly, power must be distributed equally, with no team member having more perceived power than any other. It is this leveling of the playing field that allows the team to develop and to stimulate the creative juices of its members. This article discusses techniques that can help an organization break down the power barriers and permit its employees to become a cohesive unit--a team.

Creativity↗
PubMed1997

Comparison of two methods of bedside blood glucose screening in the NICU: evaluation of accuracy and reliability.

Bedside whole blood glucose screening in the NICU has been an accepted method of care for several years. Meters or visually read reagent strips are used in bedside screening, but the reliability and accuracy of these methods are not always established before they are implemented as routine practice in the NICU. A study was conducted to determine which method of bedside whole blood glucose screening was the more accurate: visually read Chemstrip bG reagent strips or the One Touch II meter method. The values obtained were compared with lab analysis of serum glucose, and a correlation study was performed to compare the accuracy and reliability of the values produced by the two methods. One hundred samples were obtained from 38 NICU infants; 63 percent of the 100 samples were compared with lab values. Results revealed that the One Touch II method was more reliable (r = .92) than the Chemstrip bG method (r = .87). Furthermore, the One Touch II results correlated better with lab values when the meter was not operated in the neonatal mode. This study revealed that the One Touch II method appears to provide safe and accurate screening of bedside blood glucose in a high-risk neonatal population.

Blood Glucose↗
PubMed1997

Coping with cancer.

In summary, the manner in which an individual and his or her family and friends adapt to the diagnosis of cancer is quite individual and complicated, and depends on a number of factors. It is important that patients realize that they should acknowledge their feelings to their physicians, family and friends so that these feelings can be validated. In this way they can be helped to find resources to enhance their coping abilities. There are many support groups that are now available for patients in various areas of cancer treatment. Efforts are underway to bring more of these issues to light in medical training so that physicians may be better prepared to strengthen a person's ability to cope with cancer and to live to the fullest extent possible.

Adaptation, Psychological↗
PubMed1997

Tacrolimus: a superior agent to OKT3 for treating cases of persistent rejection after intrathoracic transplantation.

Acute myocardial rejection refractory to treatment still contributes significantly to patient death after intrathoracic transplantation. A historical series of 25 patients who received OKT3 (5 mg/day for 10 days) was compared with our current experience with 14 patients treated with tacrolimus (0.1 mg/kg/day targeting whole blood concentrations of 13 to 18 ng/ml): all 39 patients having persistent rejection unresponsive to treatment at the time of conversion. Mean periods of follow-up were 842.9 days and 342.6 days, respectively. Actuarial 1-year patient survival rates were 64.0% and 76.2% for the OKT3 and tacrolimus treatment groups, with most of the deaths in the OKT3 group occurring early (p = 0.064). Causes of death for patients receiving OKT3 included acute rejection (n = 5), infection (n = 3), carcinoma (n = 2), multiorgan failure (n = 1) and graft vessel disease (n = 1). The two deaths in the tacrolimus treatment group were the result of infections. Eighty percent of patients treated with OKT3 subsequently experienced further rejection episodes, in many cases necessitating methotrexate therapy. In contrast, only one patient (7.1%) from the tacrolimus group was diagnosed with rejection after conversion (p < 0.001). In conclusion, when compared with OKT3 therapy, a switch in baseline immunosuppression from cyclosporine to tacrolimus seems to be markedly more effective, as well as being safe for the treatment of persistent acute rejection.

Actuarial Analysis↗
PubMed1997

[Direct carotid-cavernous fistula. Clinical, radiologic and therapeutic studies. Apropos of 49 cases].

MATERIALS AND METHODS: From 1977 to 1996, 49 direct carotido-cavernous fistulae were studied among the sixty some cases diagnosed over these 20 years. Five were caused by spontaneous rupture of an intracavernous aneurysm and the others were caused by trauma. RESULTS: The clinical presentation in 37 patients was exophthalmia with pulsating conjunctival hyperhemia and vascular murmur. Some cases had a neurological syndrome suggesting cavernous involvement. A bilateral presentation was observed in 2 cases. One patient had no ophthalmologic syndrome but had a vascular murmur. Prior to 1982, all patients were treated and cured by occlusion of the internal carotid after direct access via the neck using a 3 F Fogarty catheter. Since 1982, patients have been treated with the detachable balloon technique. The carotid was preserved in 16 cases. In one case, secondary thrombosis occurred due to major dissection. In one case, the size of the breach was too small for the balloon so a coil was used. In one other case, insertion of the guide wire and catheter was sufficient to occlude the fistula. There was one death during treatment due to fistula rupture and one partially regressive right hemiplegia which could not be explained. This patient also developed left hemiplegia two years later, again with no explaining cause. Cure was achieved in the other patients without sequellae. DISCUSSION: Direct carotido-cavernous fistulae due to rupture of an aneurysm or trauma are uncommon. When flow through the breach is minimal, vascular treatment may not be necessary unless clinical signs appear since this type of fistula heals spontaneously. In other cases, an endovascular balloon procedure is indicated. There are few complications. Embolization with coils or other devices should only be used in selected cases when the breach is too small for the balloon.

Adolescent↗
PubMed1997

Factors influencing kidney transplantation in Manchester, UK: 1989-1996.

The Manchester renal transplant center has the highest single center activity in the UK at present and has managed to achieve high posttransplant survival rates. We believe that this success is due to a combination of factors including a conservative approach to patient management; changes in clinical practice are only made after the evidence base has been established. This center is committed to the philosophy of prolonged survival of all transplanted kidneys. We believe that transplanting kidneys into clinically high-risk patients is not the best use of available resources.

Adult↗
PubMed1996

A tightly regulated high level expression vector that utilizes a thermosensitive lac repressor: production of the human T cell receptor V beta 5.3 in Escherichia coli.

A series of vectors has been constructed to express the human T cell receptor V beta 5.3 under the control of the hybrid trc promoter in Escherichia coli. Transcriptional induction of the trc promoter was achieved chemically by using isopropyl beta-D-thiogalactopyranoside (IPTG) in a bacterial strain that harbors the lacIq gene, or thermally by using the mutant lacIts gene that encodes a temperature-sensitive lac repressor [Bukrinsky et al. (1988) Multicopy expression vector based on temperature-regulated lac repressor: expression of human immunodeficiency virus env gene in Escherichia coli. Gene 70, 415-417]. Several of the plasmids tested also contain the E. coli heat-stable enterotoxin II (STII) signal sequence for protein secretion. In addition, the gene 10 leader sequence from bacteriophage T7 and a minicistron localized upstream of the V beta 5.3 coding sequence were tested for their potential effect on protein production. These elements increased protein yield two-fold when transcription was induced by IPTG, but had no detectable effect on protein yield when transcription was induced thermally. The highest protein yield was obtained when V beta 5.3 was expressed either from plasmid pKB containing the STII signal in strain LJ24, or from plasmid pKBi that lacks the signal sequence, in the protease deficient strain SG21173 (lon, htpR. clp). Both plasmids contain the lacIts gene, the trc promoter, the two transcription terminators of the rrnB operon, and a tetracycline selection marker. Production of V beta 5.3 using pKBi-V beta 5.3 in strain SG21173 in a 5-liter fermenter under controlled growth conditions yielded over 25 mg V beta 5.3/liter culture. Conversion of the lacIts to the lacIqts gene yielded vector pKBiq-V beta 5.3 which exhibits complete repression of the trc promoter at 30 degrees C. This stringent regulation of the thermally inducible trc promoter, the elimination of IPTG, the inclusion of the tetracycline resistance gene, and the high level of protein yield should render this expression system broadly useful for the high level production of heterologous proteins in E. coli, for both basic research and human therapeutic applications.

Amino Acid Sequence↗
PubMed1996

Selective activation of CD8 T cell effector functions by epitope variants of lymphocytic choriomeningitis virus glycoprotein.

We provide evidence for selective activation of different effector functions of CD8+ T lymphocytes by altered peptide ligands. A T cell epitope from the glycoprotein of lymphocytic choriomeningitis virus (p33-41) and single amino acid variants thereof were used for primary in vitro induction of CTL clones. When the CTL were analyzed for cytotoxicity, proliferation, IFN-gamma production, and Ca2+ mobilization, we found that some of the clones showed activation of only their cytotoxic effector function when stimulated with variants of their inducing peptides. For one clone, cytotoxic reactivity was readily detected to the inducing peptide and three of four variants, but only the former was also able to trigger proliferation, IFN-gamma production, and Ca2+ mobilization. Another clone also revealed this dichotomy, but in this case some of the altered peptide ligands in addition to the inducing peptide were able to stimulate the full spectrum of effector functions, whereas others only stimulated cytotoxicity. A third clone revealed inefficient triggering of some effector functions by the peptide variants. Our data suggest that, as described for CD4 T cells, altered peptide ligands may lead to partial activation of effector functions of CD8 T cells. In addition, ligands with glycine substitutions in potential TCR contact positions induced CTL, which were able to recognize peptides with a variety of amino acids in the former glycine position.

Animals↗