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J W London

Publications and source records attributed to J W London.

At least 19 recordsLinked to original sources
PubMed2000

Overview of the Internet and prostate cancer resources.

The hallmark of the age of personal computers is the ability to obtain information and communicate with others on nearly any subject using a computer connected to the global network known as the Internet. Information on many diseases is available on the World Wide Web. Information on prostate cancer, including its characteristics, diagnosis, and treatment, is abundantly present on the Internet. This article provides an overview of Internet prostate cancer resources, presenting a brief history of the Internet and its ubiquitous application, the World Wide Web, with a discussion of search engines, the utilization of web resources by physicians (including evaluating web sites, and a highly selected list of noteworthy sites), and the growing use of electronic mail (e-mail) in the patient-physician relationship.

Humans↗
PubMed1995

Cost effective Internet access and video conferencing for a community cancer network.

Utilizing the ubiquitous personal computer as a platform, and Integrated Services Digital Network (ISDN) communications, cost effective medical information access and consultation can be provided for physicians at geographically remote sites. Two modes of access are provided: information retrieval via the Internet, and medical consultation video conferencing. Internet access provides general medical information such as current treatment options, literature citations, and active clinical trials. During video consultations, radiographic and pathology images, and medical text reports (e.g., history and physical, pathology, radiology, clinical laboratory reports), may be viewed and simultaneously annotated by either video conference participant. Both information access modes have been employed by physicians at community hospitals which are members of the Jefferson Cancer Network, and oncologists at Thomas Jefferson University Hospital. This project has demonstrated the potential cost effectiveness and benefits of this technology.

Computer Communication Networks↗
PubMed1992

A network scanner image management station.

Distributed computing can be applied to CT or MRI scanner image acquisition, printing, and archiving by interfacing the scanner with a computer network. Also on the network must be a computer workstation that has image management software to capture the images sent over the network by the scanner. This software must also allow the radiology staff to print and archive the images. Several benefits are realized by this network configuration. First, the scanner console is solely used for scanning patients; delays are not encountered because the console is being used for printing and archiving images. Also, the workstation printing software can be developed so that useful features not available at the scanner console can be incorporated. Finally, sophisticated archiving strategies can be implemented at the workstation. We have developed a network image management station at the Fox Chase Cancer Center using a reduced instruction set computer (RISC) workstation. Hardware and software is utilized to convert all scanner image data to the American College of Radiology-National Electrical Manufacturers Association format. All workstation software is developed using the open X-Windows standard. Digital audio tape is used for image archiving.

Computer Communication Networks↗
PubMed1991

The use of X-terminals as clinical workstations.

The Medical Computer Facility at the Fox Chase Cancer Center has installed X-terminals in patient examination rooms and at nursing stations for clinical data access by physicians and nurses. The X-terminals are connected to UNIX operating system RISC processors via Ethernet. The RISC processors communicate with databases on a minicomputer cluster. Simultaneous presentation of textual (e.g., pathology and radiology reports) and graphical (e.g., clinical laboratory results) clinical data is provided under X-Windows. CT and MRI images can also be displayed in windows. Our experiences implementing X-terminal clinical workstations in a production environment will be discussed.

Cancer Care Facilities↗
PubMed1988

Effective computing with clusters.

Fox Chase Cancer Center has adopted the "cluster concept" of networking to avoid redundancy and loss of computing time. In this manner, transfer of clinical and research data is easily accomplished.

Cancer Care Facilities↗
PubMed1985

Quantitative analysis of liver function in percutaneous transhepatic biliary drainage patients.

The diagnostic usefulness of Tc-99m DISIDA cholescintigraphy as a predictor of eventual catheter and hepatic function in patients who have undergone percutaneous transhepatic biliary drainage (PTBD) for extrahepatic biliary obstruction was evaluated. Twenty-nine cholescintigrams were performed in 14 patients. The examinations were divided into two groups: Group A (N = 17), in which the patient's clinical status deteriorated within two to three days post-PTBD, and Group B (N = 12), in which the patients did well clinically post-PTBD. No significant difference between the two groups was demonstrated by visual analysis of the analog images or by analysis of serum bilirubin levels. A computer program, developed by the authors, quantitates several parameters of DISIDA kinetics, reflecting hepatic function based upon compartmental analysis. A significant difference (P less than .001) was demonstrated between the mean transport constants (blood clearance constant = k1; hepatic clearance constant = k2) for the two groups. It is concluded that serum bilirubin levels and visual inspection of analog images are inadequate independent predictors of hepatic function in patients post PTBD. The transport constants k1 and k2 are quantitative parameters of hepatic function that may be of prognostic value in patients post PTBD.

Adult↗
PubMed1983

Automated calculation of gallbladder ejection fraction.

We have developed a computer method which by automatically locating the border of the gallbladder in each image and subtracting a varying location-dependent background corresponding to the gallbladder border overcomes the difficulties associated with quantitating gallbladder contraction. These difficulties are attributable to significant and changing background activity, imprecise manual delineation of the gallbladder, and the changing position and shape of the gallbladder. Validation studies using a gallbladder phantom showed the method to be very accurate. No significant difference (P greater than 0.05) was observed between the expected and calculated ejection fractions. Ten patient studies were analyzed, with a resulting range of gallbladder ejection fractions of 22-79%. Excellent reproducibility was obtained with an average intraobserver coefficient of variation of 3.5%, and no statistically significant difference in interobserver measurements (P greater than 0.05). The regression line for interobserver measurements had a slope of 0.96 +/- 0.08, an intercept of 1.6 +/- 4.0%, and a correlation coefficient of 0.99. From these preliminary results we conclude that this method offers a reliable means of quantitating gallbladder contraction.

Cholecystokinin↗
PubMed1983

Fourier analysis of a gated blood-pool study during atrial flutter.

First-harmonic Fourier analysis of a gated blood-pool study is based on the assumption that the cardiac chambers contract once per cardiac cycle. In atrial arrhythmias this condition may not exist for the atria. We recently studied a patient with atrial flutter and 2:1 atrioventricular conduction. There were predictable alterations in the first-harmonic Fourier phase and amplitude images. The observed changes from first-harmonic Fourier analysis were: (a) very low atrial amplitude values, and (b) absence of identifiable atrial regions on the phase image.

Aged↗
PubMed1982

Transport of beta-hydroxy-beta-methyl-glutarate and beta-hydroxbutyrate by renal brushborder membrane vesicles.

The uptake of beta-hydroxy-beta-methyl-glutarate (HMG) and beta-hydroxy-butyrate (beta-HB) by renal brushborder membrane vesicles prepared from normal and starved rats was examined. HMG and beta-HB uptake show a Na+ gradient-induced overshoot, suggesting luminal cotransport of these organic acids. Kinetic analysis of HMG and beta-HB uptake revealed a single component carrier system and a diffusional component for each compound. Vesicles from starved rats exhibit the same transport characteristics as those from normal rats. The transport interactions of other organic acids with HMG were examined and revealed that citrate is a competitive inhibitor, which implies that the compounds share a common organic acid carrier.

3-Hydroxybutyric Acid↗
PubMed1982

Application of response surface methodology to the assay of gamma-glutamyltransferase.

Response surface methodology (RSM) offers an empirical approach to the study of clinical enzyme assays. Variables such as pH, which are difficult to characterize by using theoretical enzyme kinetics, are easily included in RSM formulations. In this investigation, we studied with RSM the change in the measured activity of gamma-glutamy-transferase (EC 2.3.2.2) as a function of changes in concentrations of donor (gamma-glutamyl-3-carboxy-4-nitroanilide) acceptor (glycylglycine), and pH. The study defined large ranges for these variables over which maximum enzyme activity is obtained: donor 6.6 to 10.2 mmol/L, acceptor 129 to 250 mmol/L, and pH 7.8 to 8.5. The RSM regression polynomial was as accurate as a previously determined enzyme kinetic equation for predicting the transferase activity from given reagent substrate concentrations. Although not yielding a mechanistic understanding of an enzyme assay, RSM studies do produce an operational understanding of how an assay functions.

Clinical Enzyme Tests↗
PubMed1980

Electrophoretic, kinetic, and immunoinhibition properties of gamma-glutamyltransferase from various tissues compared.

gamma-Glutamyltransferase (EC 2.3.2.2) from human liver, kidney, pancreas, and duodenum migrated in acrylamide gels (65 g/L) as a single band with the following decreasing order of electrophoretic mobility: liver > pancreas > kidney > duodenum. The initial velocity kinetic constants of pancreatic and duodenal gamma-glutamyltransferase and of the enzyme in human serum were determined and compared with those we previously established for the enzyme from human kidney, liver, and serum. The greatest differences were in the glycylglycine competitive-inhibition constants: kidney gamma-glutamyltransferase was the most strongly inhibited and pancreatic enzyme the second most strongly inhibited by high concentrations of glycylglycine, with the liver and duodenal isoenzymes only slightly inhibited and the enzyme in serum not inhibited over the concentration range (0-150 mmol/L) of glycylglycine used. Differences between the other kinetic constants of these isoenzymes were much smaller. Human liver gamma-glutamyltransferase was obtained in a highly purified form by a six-step procedure that included papain digestion of the original homogenate. Rabbit antisera raised against this preparation inhibited liver, kidney, and pancreatic gamma-glutamyltransferase activity equally well (78, 76, and 78% inhibition, respectively), but inhibited the hog-kidney enzyme only slightly (1%). We conclude that the polypeptide portions of the isoenzyme molecules are structurally similar but that the carbohydrate moieties differ significantly in structure and topography.

Duodenum↗
PubMed1979

Comprehensive analysis of a Radiology Operations Management computer system.

The Radiology Operations Management computer system at the Hospital of the University of Pennsylvania is discussed. The scheduling and file room modules are based on the system at Massachusetts General Hospital. Patient delays are indicated by the patient tracking module. A reporting module allows CRT/keyboard entry by transcriptionists, entry of standard reports by radiologists using bar code labels, and entry by radiologists using a specialty designed diagnostic reporting terminal. Time-flow analyses demonstrate a significant improvement in scheduling, patient waiting, retrieval of radiographs, and report delivery. Recovery of previously lost billing contributes to the proved cost effectiveness of this system.

Appointments and Schedules↗
PubMed1978

Isolation of gamma-glutamyltransferase from human liver, and comparison with the enzyme from human kidney.

We isolated gamma-glutamyltransferase [(gamma-glutamyl)-peptide:amino acid gamma-glutamyltransferase, EC 2.3.2.2] from human liver and compared some of its properties with the same enzyme prepared from human kidney. The enzymes from these two sources are very similar with respect to initial velocity kinetic constants, pH optima of the transpeptidation and autotransfer reactions, heat stability, competitive inhibition by glutathione of the colorimetric assay in which gamma-glutamyl-4-nitroanilide is substrate, stability of catalytic activity to trypsinization, and relative rates of transfer of the gamma-glutamyl moiety from gamma-glutamyl-4-nitroanilide and L-[glycine-2-3/]glutathione to some amino acids and small peptides. The kidney enzyme is inhibited more by the gamma-glutamyl acceptor substrate, glycylglycine, as reflected in a sevenfold lower value for the inhibition constant KiA. Major differences were observed in the lectin-binding properties of liver gamma-glutamyltransferase compared to the kidney enzyme. Lectin-binding property differences are retained for the trypsinized form of the liver and kidney enzymes, although the degree of precipitation was less for certain lectins as compared to the untreated enzyme. Lectin-binding properties were reversed by carbohydrates specific for each lectin. We adapted the histochemical staining technique of Rutenberg et al. [J. Histochem. Cytochem. 17, 517 (1969)] to the detection of gamma-glutamyltransferase activity in acrylamide gels; diffusion artifacts are minimized and the color produced is stable for several days. Untreated and trypsinized forms of the liver enzyme both migrated faster in acrylamide gels (as single bands) than did the corresponding forms of the kidney enzyme.

Humans↗
PubMed1977

Ontogeny of glycine transport in isolated rat renal tubules.

Isolated renal tubule preparations were made from newborn Sprague-Dawley rats and used to study initial entry rate kinetics of glycine. The results were compared to those obtained in the isolated tubule preparation from the adult rat kidney. While initial rates of glycine uptake were identical for newborn and adult tubules, significant differences in influx kinetics were demonstrated. Of the two apparent transport Km systems shown to be present in the newborn tubule, the high-affinity, low-capacity system accounts for about 40% of total glycine uptake at physiologic concentrations. The high-affinity, low-capacity system of the adult tissue accounts for about 10% of total uptake at the same concentration range. The data lend strength to the argument against the concept that the physiologic hyperglycinuria of the newborn rat is due to either impaired ability to concentrate glycine intracellularly or to absence of one or more transport mechanisms for glycine.

Animals↗
PubMed1977

Gamma-Glutamyltransferase: kinetic properties and assay conditions when gamma-glutamyl-4-nitroanilide and its 3-carboxy derivative are used as donor substrates.

The kinetics of human serum gamma-glutamyltransferase (EC 2.3.2.2) were investigated, with use of glycylglycine as a gamma-glutamyl acceptor substrate and gamma-glutamyl-4-nitroanilide and its carboxy derivative, gamma-glutamyl-3-carboxy-4-nitroanilide, as donor substrates. The simultaneous occurrence of both gamma-glutamyltransfer and autotransfer was established by descending paper chromatography. Constant-ratio double-reciprocal plots confirm that the enzyme mechanism is nonsequential (ping-pong bi-bi). Inhibition by either donor was not found, and inhibition by glycylglycine was only observed at concentrations above those of clinical interest. Kinetic constants obtained by nonlinear regression analysis of initial velocity data were used to determine reagent substrate concentrations for the assay of this enzyme. An assay with use of 4 mmol of gamma-glutamyl-3-carboxy-4-nitroanilide and 100 mmol of glycylglycine per liter yielded equivalent activities to those by assay with use of 4 mmol of gamma-glutamyl-4-nitroanilide and 40 mmol of glycylglycine per liter. These concentrations of the carboxy donor and glycylglycine are also "cost optimal" and present no procedural problems when used.

Anilides↗