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Biomedical subjects

S Carter

Publications and source records attributed to S Carter.

At least 127 records · Page 7Linked to original sources
PubMed1986

Ureterorenal endoscopy: which instrument, what cost?

This report describes the design, availability, repair facilities and costs of rigid ureteroscopes. Clinical factors affecting design are detailed. A classification is given. A new test of flow dynamics is described. Short operating ureteroscopes with a stable or integral telescope system appear to be superior to other types, especially as they may be used for antegrade ureteroscopy.

Endoscopes↗
PubMed1986

Uptake pathways for amino acids in mouse intestine.

This paper characterizes amino acid (AA) uptake pathways in an everted-sleeve preparation of mouse jejunum. AA uptake is linear with time for 2-4 min, depending on the particular AA and its uptake rate. Escape of tracer to the serosal surface is still negligible at these times. Errors due to metabolism of labeled AAs to volatile products can be minimized by using 14C- rather than 3H-labeled AAs and by not drying tissues before counting. The dependence of AA uptake on concentration shows saturable kinetics, with apparent Km values in the range 1-4 mM. By 25 or 50 mM an uptake plateau is reached for leucine, lysine, methionine, and methylaminoisobutyric acid but not for aspartic acid, histidine, or proline. Proline kinetics are the result of a saturable Na+-dependent component, a linear diffusional component, and possibly a small saturable Na+-independent component. The Na+-dependent component of uptake for six AAs averages 83% of the total at 0.01 mM and 54% at 25 or 50 mM. Leucine and D-glucose exhibit modest (32%) cross-inhibition of Na+-dependent uptake. For the same six AAs we determined the percent inhibition of both the Na+-dependent and the Na+-independent components by the other AAs. These results suggest the presence of at least five or six AA uptake pathways in mouse jejunum: distinct Na+-dependent pathways for acidic, basic, and neutral AAs and for imino acids; a shared Na+-independent pathway for basic and neutral AAs; and possibly a Na+-independent pathway for acidic AAs. Comparisons of AA uptake pathways in mouse, rabbit, and rat intestine reveal many similarities but also some differences.

Amino Acids↗
PubMed1986

Improved survival duration with combination chemotherapy induction for multiple myeloma: a Southwest Oncology Group Study.

Four hundred forty previously untreated patients with active multiple myeloma were entered into a randomized trial (Southwest Oncology Group [SWOG] study 7927/28) comparing vincristine, melphalan, Cytoxan (Mead Johnson & Company, Evansville, Ind), and prednisone (VMCP) alternating with vincristine, BCNU, Adriamycin (Adria Laboratories, Columbus, Ohio) and prednisone (VBAP) with or without levamisole with vincristine, Cytoxan, and prednisone (VCP) with or without levamisole for induction therapy. The treatment groups were well balanced for all of the known major prognostic factors. Patients receiving VMCP-VBAP responded (greater than or equal to 75% regression) more frequently to induction therapy, both without (54%) and with (44%) levamisole v VCP without (28%) or with (28%) levamisole (P less than .001). In addition, patients receiving VMCP-VBAP (+/- levamisole) had a survival duration determined to be significantly increased by all forms of analysis: 48 and 33 months for VMCP-VBAP without and with levamisole v 29 and 26 months for VCP without and with levamisole (P = .011 overall). Levamisole did not improve response rates or survival duration (P greater than or equal to .1), nor did it prolong remission in the maintenance phase (P = .85). Analysis of SWOG study 7704/05 (updated April 1985) confirmed improved survival for combination therapy v MP, but no benefit for levamisole. The overall findings support the use of VMCP-VBAP as an excellent treatment option for remission induction in patients with active myeloma of all stages and prognostic categories.

Actuarial Analysis↗
PubMed1985

Problems in ANA test interpretation: a comparison of two substrates.

Comparison of serum antinuclear antibody (ANA) test results on commercial HEp-2 cell culture preparations and fixed mouse kidney sections demonstrated significant differences in end-point titers and pattern production. When manufacturer's suggested screening titers are used, there is also a significant difference in qualitative results and correlation with clinical status. With individual intralaboratory establishment of screening titer levels, some of these differences become less significant, although this study suggests that mouse kidney substrate slides are more sensitive in detecting nonspecific ANA, and that HEp-2 substrate slides are more specific in detecting ANA from cases of systemic lupus erythematosus. Antinuclear antibody substrate selection must be based on classic sensitivity-specificity considerations and the clinical correlation performance desired. Comparisons of interlaboratory or follow-up ANA results are invalid without consideration of substrate variations. Regardless of substrate utilized, each laboratory should establish its own individual screening titers in relation to suitable age groupings.

Animals↗
PubMed1984

Compound 48/80 impairs cytokinesis in murine leukemic cells.

Compound 48/80 (poly-p-methoxyphenethylmethylamine), an agent commonly used to trigger degranulation of mast cells, at concentrations of 5-20 micrograms/ml suppresses the proliferation of L1210 and Friend leukemic cells in vitro, inducing the formation of giant cells, which are polykaryons. Both the proportion of polykaryons in cultures and their size (which reflects the number of nuclei per polykaryon) increase during growth in the presence of 48/80 up to 48 hr; thereafter, the cells lose viability. A predominant number of nuclei in these polykaryons contain a 4C, or higher DNA content. The data indicate that compound 48/80 impairs the cleavage (cytokinesis) and perhaps mitotic processes. Mechanisms by which compound 48/80 induces the described effects are unknown but may be related to the polycationic nature of the polymer and its interaction with the cell membrane. Certain attributes of compound 48/80 suggest that this or similar polymers may have value as research tools for the study of regulatory mechanisms involved in cell division.

Animals↗
PubMed1984

Signal averaged electrocardiography in infants and children with congenital heart disease.

Forty-four patients with congenital cardiac disease underwent surface averaged electrocardiography using a high resolution purpose built module. Twelve patients had complete transposition of the great vessels, 14 had tetralogy of Fallot, 5 had ventricular septal defects, 6 atrial septal defects, 3 atrioventricular septal defects and 4 patients had miscellaneous non-structural abnormalities. All patients with structural disorders underwent corrective or palliative surgery. The aim of the study was to examine the feasibility of the method and its usefulness in detecting His potentials and delayed potentials in the ST segment. A His potential was recorded in 30 patients (68%) with an amplitude ranging from 1.25 to 8.25 microV. Delayed potentials were recorded in only 1 patient with frequent ventricular premature beats. This technique may be useful in assessing intraventricular conduction times in patients with bundle branch block and/or axis deviation especially those who are at risk from intermittent complete AV block after surgical intervention. Detection of delayed potentials may allow better assessment of post-operative risk of ventricular arrhythmias in patients who have undergone ventricular surgery.

Bundle of His↗
PubMed1984

Effects of [3H]UdR on the cell-cycle progression of L1210 cells.

Tritium-labelled uridine [( 3H]UdR) perturbs progression of L1210 cells through the mitotic cycle. The main effect manifests as a slowdown or arrest of a portion of cells in G2 and is already observed 2 hr after addition of 0.5-5.0 microCi/ml of [3H]UdR into cultures. At 2.5-5.0 microCi/ml of [3H]UdR a slowdown of cell progression through S is also apparent. Additionally, there is an increase in the number of cells with DNA values higher than 4C in cultures growing in the presence of [3H]UdR for 8-24 hr. A pulse of [3H]UdR of 2 hr duration labels predominantly (95%) cellular RNA. The first cell-cycle effects (G2 slowdown) are observed when the amount of the incorporated [3H]UdR is such that, on average there are fewer than thirty-six [3H] decays per cell which corresponds to approximately 12-19 rads of radiation. The S-phase slowdown is seen at a dose of incorporated [3H]UdR twice as high as that inducing G2 effects. The specific localization of [3H]UdR in nucleoli, peripheral nucleoplasm and in cytoplasm, as well as differences in the kinetics of the incorporation in relation to phases of the cell cycle are discussed in the light of the differences between the effects of [3H]UdR and [3H]thymidine. Mathematical modelling of the cell-cycle effects of [3H]UdR is provided.

Animals↗
PubMed1984

When your staff is cut: how one hospital coped with a one-third reduction in security officers.

With many hospitals struggling with DRG's and growing competition for patients, budget reduction in security and elsewhere is becoming more and more prevalent. Forced to deal with a severe cut in its security officers' staff in 1980, New England Memorial Hospital's security department has survived for four years by taking a number of steps that have achieved more with less. Here are some of the lessons learned.

Hospital Bed Capacity, 300 to 499↗
PubMed1984

The personal computer: getting the information you need for the least cost.

By acquiring a relatively low cost personal computer and certain software, you can reduce the time now spent on costly manual operations in security, safety, and telecommunications management. At the same time, you can improve both your department's performance and its value as a resource for other departments.

Computers↗
PubMed1983

A randomized phase III study of cisplatin with or without methotrexate for recurrent squamous cell carcinoma of the head and neck. A Northern California Oncology Group study.

Eighty patients with recurrent squamous cell cancer of the head and neck were randomized to cisplatin (80 mg/m2) every 3 weeks or cisplatin plus weekly methotrexate (250 mg/m2) with leucovorin. The overall response rate to cisplatin was 18%, with 10% complete responses. The overall response to the combination was 33% with 18% complete responses (P = 0.11). There was no difference in response duration, time to progression, or survival. There was no difference in renal toxicity between the 2 arms (creatinine greater than 2 mg/dl in 6% of the patients). There was significantly more leukopenia (64%), thrombocytopenia (18%), anemia (18%), and mucositis (33%) in the combination arm. This combination of two of the best agents for head and neck cancer did not improve response, but resulted in added toxicity.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1981

Plasma carcinoembryonic antigen in the diagnosis and management of patients with hepatocellular carcinoma.

The value of serial carcinoembryonic antigen (CEA) measurements as a marker of disease progression or in monitoring treatment was investigated in patients with hepatocellular carcinoma. Of 40 patients, including 16 with normal serum alpha-fetoprotein (AFP) concentrations, 29 (72.5%) had abnormal plasma CEA at presentation. Although this was more common in patients with pre-existing cirrhosis, the mean and range of plasma CEA were similar in patients with and without pre-existing hepatic disease. There was no correlation between plasma CEA and any biochemical parameter of hepatic function, although plasma CEA concentrations were significantly lower in patients with well-differentiated tumors. CEA concentrations increased in 71% of patients who had no response to cytotoxic drugs, but CEA also increased in 62.5% of those patients who did respond. Plasma CEA concentrations were elevated in 62.5% of patients with normal and 79% of patients with raised serum AFP on admission to the hospital. There was no correlation between individual AFP and CEA concentrations. Although elevated plasma CEA levels may be of diagnostic value in patients with hepatocellular carcinoma in the absence of pre-existing hepatic disease, and in those with normal serum AFP, our findings indicate that it does not behave as a true tumor marker.

Carcinoembryonic Antigen↗
PubMed1980

Reflux gastritis syndrome: mechanism of symptoms.

Despite numerous observations indicating the deleterious effect of refluxed intestinal contents upon the stomach, the mechanism of injury and symptoms in the reflux gastritis syndrome is unclear. Much speculation has centered around the role of bile acids in the production of symptoms and histologic damage. Accordingly, the aims of our study were (a) to determine whether administration of autologous intestinal contents into the stomach can produce the symptoms of the reflux gastritis syndrome, (b) to measure and conpare the concentrations of bile acids in upper intestinal contents of postsurgical patients with and without the syndrome, and (c) to determine whether artificial bile acid solutions can reproduce the symptoms reported by the patients. Eleven patients with reflux gastritis syndrome and 10 asymptomatic postgastric surgery patients were evaluated. Autologous intestinal contents obtained after cholecystokinin injection and normal saline were infused in a random, double-blind fashion into the stomach of the patients. Determinations for total and individual bile acids, as well as the bile acid conjugated/unconjugated and glycine/taurine ratios were made on aliquots of upper intestinal contents of symptomatic and asymptomatic patients. Finally, saline and two artificial bile acid solutions with bile acid compositions similar to those of upper intestinal contents from symptomatic and asymptomatic patients were infused in random, double-blind fashion into the stomach of 8 patients from each group. Positive symptom responses to autologous intestinal contents were found in 10 of 11 symptomatic patients and only 2 of 10 asymptomatic patients (P < 0.01), both of whom showed positive responses to both autologous intestinal contents and saline. No symptomatic patients had a positive response to saline. Symptomatic patients had bile acid concentrations significantly greater (P < 0.001) than asymptomatic patients. A positive response to artificial bile acid solution infusion was found in only 1 symptomatic patient. It is concluded that (a) symptoms of the reflux gastritis syndrome are reproduced by gastric infusion of upper intestinal contents and (b) bile acids alone are not responsible for the production of symptoms.

Adult↗