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C Porter

Publications and source records attributed to C Porter.

At least 37 records · Page 2Linked to original sources
PubMed1999

Progress in Two-Dimensional and Three-Dimensional Ultrasonic Tissue-Type Imaging of the Prostate Based on Spectrum Analysis and Nonlinear Classifiers.

Spectrum analysis of radiofrequency (RF) ultrasonic echo signals often can sense tissue differences that are not visible on conventional ultrasonic images. Spectrum-analysis parameter values combined with other variables, such as serum prostate specific antigen (PSA) concentration, can be classified by neural networks to distinguish effectively between cancerous and noncancerous prostate tissues. Images based on neural network classification of spectral parameters and clinical variables can be advantageous for biopsy guidance, staging, and treatment planning and monitoring. A study based on 644 biopsies from 137 patients showed that these methods are significantly superior to B-mode image interpretation for differentiating cancerous from noncancerous prostate tissues. Using the histologic determination of tissue types as the gold standard, the area under the receiver-operator characteristic (ROC) curve for neural network classification based on spectrum analysis and PSA value for the 644 biopsies was 0.87 +/- 0.04, and the ROC curve are for a level-of-suspicion (LOS) assignment based on B-mode imaging was 0.64 +/- 0.04. Color-encoded and gray-scale images derived from neural network assignment of suspicion for cancer at each pixel location showed remarkable detail and suggested potential clinical value for biopsy guidance using real-time two-dimensional (2D) images and staging, treatment planning, and monitoring using three-dimensional (3D) images.

Journal Article↗
PubMed1998

Reproducible and efficient murine CNS gene delivery using a microprocessor-controlled injector.

To develop a reproducible gene transfer method for the murine CNS we evaluated delivery of various gene vehicles using mechanical or manual stereotaxic intracranial inoculation. A microprocessor controlled microsyringe pump (The World Precision Instruments/UltraMicroPump) programmable for volume, rate and syringe size and designed to dispense nanoliter and picoliter volumes was compared to a standard manual deliver method. Gene transfer efficiency of two viral vectors, two synthetic cationic lipid molecules, and naked DNA were evaluated in mice injected unilaterally in two brain regions. Animals received 1 microl over 10 min. of either HSVlac (1 x 10(5) b.f.u), AdLac (1 x 10(5) p.f.u), Tfx-10 or Tfx-20 (2.6 microg DNA in 2.0 microl Tfx; 1:1 charge ratio of DNA to liposome), or naked DNA (HSVlac plasmid, 10 microg/microl). After 4 days, animals from each group were perfused and tissue prepared for X-gal histochemical detection of beta-galactosidase expression. Blue cells were observed in the HSV, Adenovirus, and Tfx-20 groups only at the injection site in animals injected using the UMP. Animals injected manually exhibited fewer blue cells and positive cells were not restricted to the injection site. To quantify expression, tissue punches harvested from the injection sites as well as other brain regions were analyzed using a chemiluminescent reporter assay to detect beta-galactosidase (Galacto-Light). These data indicated increased activity in all animals injected with a lacZ containing vector via the UMP as compared to manual delivery: A 41% increase in the expression levels of beta-gal in HSVlac infected animals (p = 0.0029); a 29% increase in Adlac infected animals (p = 0.01); a 56% increase in Tfx-10 transduced animals (p = 0.04); a 24% increase in Tfx-20 transduced animals (p = 0.01); and a 69% increase in naked DNA gene transfer (p = 0.05). Total beta-galactosidase activity was greatest in HSVlac infected mice followed by Adlac > Tfx-20 > Tfx-10 = naked DNA.

Adenoviridae↗
PubMed1998

A prospective study of the use of liquid oral dietary supplements in nursing homes.

OBJECTIVE: To investigate the use of liquid oral dietary supplements among nursing home residents who were eating poorly and losing weight. DESIGN: A prospective, descriptive, anthropological study. SETTING: Two proprietary nursing homes with 105 and 138 beds. PARTICIPANTS: Purposive sampling was used to select 40 residents from among the 100 residents who were not eating well. Dietary data were collected on this sub-sample of 40 residents. MEASUREMENTS: Participant observation, in-depth interviews, event analysis, bedside dysphagia screenings, oral health examinations, body weight, body mass index (BMI), and chart review were used to collect data. Dietary data were collected over a 3-day period, and data were gathered on how supplements were ordered, served, and consumed. RESULTS: Supplements had been ordered for 29 of the subsample of 40 residents. Only nine of 29 residents were served the correct number and type of supplements as ordered by their physicians, and only two residents consumed the full amount of supplement as ordered. The overall mean percentage of supplement consumed compared with that ordered was 55.1%. Although supplements were ordered primarily to prevent weight loss and to facilitate weight gain, nearly half (n = 14) of the residents continued to lose weight. Supplements were ordered without investigating the underlying factors contributing to weight loss, such as inadequate staffing and lack of supervision at mealtime, undiagnosed dysphagia, and poor oral health. Without evaluation of these factors, it is unknown which residents might benefit from oral supplements. CONCLUSION: Findings indicate that supplements were used nonspecifically as an intervention for weight loss in nursing home residents without regard to dose, diagnosis and management of underlying problem(s), amount of supplement consumed, and outcome. Further research is needed to establish when supplements should be ordered, how to ensure that they will be taken, and whether they are effective.

Aged↗
PubMed1997

A comparison of structure-activity relationships between spermidine and spermine analogue antineoplastics.

A systematic investigation of the impact of spermidine analogues both in vitro and in vivo is described. The study characterizes the effects of these analogues on L1210 cell growth, polyamine pools, ornithine decarboxylase, S-adenosyl-L-methionine decarboxylase, spermidine/spermine N1-acetyltransferase, the maintenance of cellular charge, i.e., cationic equivalence associated with the polyamines and their analogues, and compares their ability to compete with spermidine for transport. The findings clearly demonstrate that the activity of the linear polyamine analogues is highly dependent on the length of the triamines and the size of the N(alpha),N(omega)-substituents. It appears that there is an optimum chain length for various activities and that the larger the N(alpha),N(omega)-alkyls, the less active the compound. Metabolic transformation including N-dealkylation of these compounds is also evaluated. While there is no monotonic relationship between chain length and the ability of the analogue to be metabolized, the dipropyl triamines are clearly more actively catabolized than the corresponding methyl and ethyl systems. A comparison of the triamines with the corresponding tetraamines is made throughout the text regarding both in vitro activity against L1210 cells and in vivo toxicity measurements, suggesting that several triamine analogues may offer therapeutic advantages over the corresponding tetraamines.

Acetyltransferases↗
PubMed1997

Hospital food.

Explore the source record for details and available documents.

Dietetics↗
PubMed1997

Risk of nodal metastases at laparoscopic pelvic lymphadenectomy using PSA, Gleason score, and clinical stage in men with localized prostate cancer.

Laparoscopic pelvic lymph node dissection (LPLND) is a low-morbidity procedure used to stage prostate cancer accurately prior to definitive local therapy. To better select patients for LPLND, we reviewed the clinical features of 120 patients with clinically localized prostate cancer who underwent LPLND to define significant risk factors for nodal metastases. The age ranged from 43 to 79 years (mean 68). Serum prostate specific antigen (PSA) concentration ranged from 1.3 to 329 ng/mL, Gleason score ranged from 2 to 9, and clinical stage ranged from T1b to T3c. Nodal metastases were discovered in 15 patients (13%). Among men with a Gleason score > or = 7, 21% had nodal metastases (P = 0.004). A serum PSA > 20 ng/mL and clinical stage T1b, T2b, or greater also were statistically significant predictors of lymph node metastases (20% and 19%, respectively). In multivariate analysis, Gleason score significantly predicted nodal metastases when controlling for all other clinical measures. Therefore, LPLND is indicated for any patient with a Gleason score > or = 7, PSA > 20 ng/mL, and advanced clinical T stage, independently or in combination.

Age Factors↗
PubMed1996

Empyema thoracis and lung abscess due to Gemella morbillorum.

A case of empyema and lung abscess in an elderly patient who presented with clinical features of congestive cardiac failure is described. Gemella morbillorum was cultured from pleural exudate found postmortem to be associated with a lung abscess. To our knowledge this is the first reported case of infection with this organism in this setting. We discuss the clinical spectrum and management of infection with this infrequently encountered organism.

Aged↗
PubMed1996

Indirect calorimetry in critically ill patients: role of the clinical dietitian in interpreting results.

Evaluation and interpretation of energy needs of critically ill patients require the expertise of clinical dietitians: Dietitians must be knowledgeable about the methods available to quantify energy needs and able to communicate effectively with physicians and nurses regarding nutritional requirements. Several prediction equations are available for calculating energy needs of critically ill patients. Indirect calorimetry is also used frequently to measure energy requirements in this patient population. This article defines when energy expenditure measured by indirect calorimetry may provide clinically useful information. Data obtained by indirect calorimetry must be interpreted carefully. Indirect calorimetry is based on the equations for oxidation of carbohydrate, protein, and fat. Errors in interpretation can be made when metabolic pathways other than oxidation dominate or when clinical conditions exist that affect carbon dioxide excretion from the lungs. Before incorporating data obtained from indirect calorimetry into a nutrition care plan, the clinical dietitian should carefully evaluate the following factors for a patient: clinical conditions when the measurement was made, desired weight loss or gain, tolerance to food or nutrition support, relationship between protein intake and energy need, and need for anabolism or growth. This article provides clinical examples illustrating how measured values compare with calculated values and recommendations for how to incorporate measured values into nutrition care plans.

Adult↗
PubMed1996

Validation of use of whole-cell repetitive extragenic palindromic sequence-based PCR (REP-PCR) for typing strains belonging to the Acinetobacter calcoaceticus-Acinetobacter baumannii complex and application of the method to the investigation of a hospital outbreak.

Acinetobacter spp. are being reported with increasing frequency as causes of nosocomial infection. In order to identify reservoirs of infection as quickly as possible, a rapid typing method that can differentiate epidemic strains from environmental and nonepidemic strains is needed. In 1993, a cluster of Acinetobacter baumannii isolates from five patients in the adult intensive therapy unit of our tertiary-care teaching hospital led us to develop and optimize a rapid repetitive extragenic palindromic sequence-based PCR (REP-PCR) typing protocol for members of the Acinetobacter calcoaceticus-A. baumannii complex that uses boiled colonies and consensus primers aimed at repetitive extragenic palindromic sequences. Four of the five patient isolates gave the same REP-PCR typing pattern as isolates of A. baumannii obtained from the temperature probe of a Bennett humidifier; the fifth isolate had a unique profile. Disinfection of the probe with 70% ethanol, as recommended by the manufacturer, proved ineffective, as A. baumannii with the same REP-PCR pattern was isolated from it 10 days after cleaning, necessitating a change in our decontamination procedure. Results obtained with REP-PCR were subsequently confirmed by ribotyping. To evaluate the discriminatory power (D) of REP-PCR for typing members of the A. calcoaceticus-A. baumannii complex, compared with that of ribotyping, we have applied both methods to a collection of 85 strains that included representatives of six DNA groups within the complex. Ribotyping using EcoRI digests yielded 53 patterns (D = 0.98), whereas 68 different REP-PCR patterns were observed (D = 0.99). By computer-assisted analysis of gel images, 74 patterns were observed with REP-PCR (D = 1.0). Overall, REP-PCR typing proved to be slightly more discriminatory than ribotyping. Our results indicate that REP-PCR typing used boiled colonies is a simple, rapid, and effective means of typing members of the A. calcoaceticus-A. baumannii complex.

Acinetobacter↗
PubMed1996

Regular low-dose intravenous iron therapy improves response to erythropoietin in haemodialysis patients.

BACKGROUND: Erythropoietin (Epo) is an effective but expensive treatment for anaemia in patients with chronic renal failure. Hyporesponsiveness to Epo, particularly in haemodialysis patients, is most commonly due to a functional iron deficiency, which is difficult to monitor reliably. METHODS: Forty-six stable haemodialysis patients, receiving Epo therapy, were commenced on regular low-dose intravenous iron (sodium ferric gluconate complex) at a dose of 62.5 mg/5 ml given as a slow injection post-dialysis twice weekly, weekly, or fortnightly, according to their serum ferritin levels. Haemoglobin, serum ferritin, Epo dose, and iron dose were measured at 6-weekly intervals over a 6-month period. RESULTS: At the beginning of the study, 12 patients in the group had ferritin levels of less than 100 microg/l, and were thus considered to potentially have an absolute iron deficiency. The study group was therefore split into two subgroups for the purpose of analysis, i.e. the 12 patients with ferritin levels of less than 100 microg/l at the start of the study or 'low ferritin group', and the remaining 34 patients with ferritin levels of greater than 100 microg/l at the start of the study or 'normal ferritin group'. In the low ferritin group (n=12), intravenous iron therapy increased serum ferritin levels, and produced a significant rise in haemoglobin, and a significant reduction in Epo dose. (Ferritin pre-iron, median (range) 68 (20-96) microg/l; post-iron, 210.5 (91-447) microg/l, P<0. 003, Wilcoxon. Haemoglobin pre-iron, 10.05 (8.2-11.9) g/dl; post-iron, 11.0 (9.9-11.9) g/dl, P<0.03. Epo dose pre-iron, 9000 (4000-30 000)-i.u./week, P<0.05). Similar results were obtained in the normal ferritin group (n=34) following intravenous iron therapy, with significant increases in serum ferritin levels and haemoglobin concentrations, and a significant reduction in Epo dose. (Ferritin pre-iron, 176 (103-519) microg/l; post-iron, 304.5 (121-792) microg/l, P<0.0001. Haemoglobin pre-iron, 9.85 (6.5-12.8) g/dl; post-iron: 11.25 (9.9-13.3) g/dl, P<0.0001. Epo dose pre-iron, 6000 (2000-15 000) i.u./week; post-iron, 4000 (0-15 000)-i.u./week, P<0. 005). CONCLUSION: Regular intravenous iron supplementation in haemodialysis patients improves the response to Epo therapy.

Adult↗
PubMed1995

The role of charge in polyamine analogue recognition.

A series of analogues and homologues of N1,N12-diethylspermine (DESPM) was synthesized, and their biological properties were evaluated. These tetraamines include a simple linear analogue of DESPM, N1,N12-bis(2,2,2-trifluoroethyl)spermine (FDESPM), the cyclic analogues of DESPM, N,N'-bis(4-piperidinylmethyl)-1,4-diaminobutane [PIP(4,4,4)] and N,N'-bis[2-(4-piperidinyl)ethyl]-1,4-diaminobutane [PIP(5,4,5)], and their aromatic counterparts, N,N'-bis-(4-pyridylmethyl)-1,4-diaminobutane [PYR(4,4,4)] and N,N'-bis[2-(4-pyridyl)ethyl]-1,4-diaminobutane [PYR(5,4,5)]. The analogues FDESPM, PIP(4,4,4), and PYR(4,4,4) have distances between their nitrogen atoms almost identical to those of DESPM. The longer analogues PIP(5,4,5) and PYR(5,4,5) are very similar in the spacing of their amino groups. However, the pKa of the nitrogens in the groups differ; thus, the extent of protonation and the charge characteristics among the members of the groups differ. A comparison of the biological properties of these compounds clearly demonstrates that the tetraamines must be charged to be "recognized" by the cell. Analogues with low nitrogen pKa's such that the nitrogens are poorly protonated at physiological pH do not compete well with spermidine for uptake and, as expected, have high 96 h IC50 values and have little effect on S-adenosylmethionine decarboxylase, ornithine decarboxylase, and spermidine/spermine N1-acetyltransferase activities and on intracellular polyamine pools.

Acetyltransferases↗
PubMed1995

Stethoscope contamination in the neonatal intensive care unit.

The level of contamination of stethoscopes used in a neonatal intensive care unit was studied, along with the practices used for cleaning these items. A policy of alcohol cleaning was introduced and the effect of this change on the level of bacterial growth was observed after a six-week period. It was found that 71% of stethoscopes had a significant bacterial growth and that this was reduced to 30% after the cleaning procedure change (P < 0.05). Stethoscopes and other equipment are a potential source of nosocomial infection on the neonatal intensive care unit.

Alcohols↗