How I spent my summer vacation.
Explore the source record for details and available documents.
Camping↗
Biomedical subjects
J Johnson
Publications and source records attributed to J Johnson.
4-Pyridin-5-yl-2-(3,4,5-trimethoxyphenylamino)pyrimidines: potent and selective inhibitors of ZAP 70.
Activation of the tyrosine kinase ZAP 70 has been shown to be crucial to the transduction of the T-cell receptor signalling pathway, which leads ultimately to proliferation, cytokine gene expression and T-cell effector functions. A series of 2-phenylaminopyrimidines have been identified as potent and selective inhibitors of ZAP 70.
Phosphorylation↗
Proteasome inhibitors: a novel class of potent and effective antitumor agents.
The ubiquitin-proteasome pathway plays a critical role in the regulated degradation of proteins involved in cell cycle control and tumor growth. Dysregulating the degradation of such proteins should have profound effects on tumor growth and cause cells to undergo apoptosis. To test this hypothesis, we developed a novel series of proteasome inhibitors, exemplified by PS-341, which we describe here. As determined by the National Cancer Institute in vitro screen, PS-341 has substantial cytotoxicity against a broad range of human tumor cells, including prostate cancer cell lines. The PC-3 prostate cell line was, therefore, chosen to further examine the antitumor activity of PS-341. In vitro, PS-341 elicits proteasome inhibition, leading to an increase in the intracellular levels of specific proteins, including the cyclin-dependent kinase inhibitor, p21. Moreover, exposure of such cells to PS-341 caused them to accumulate in the G2-M phase of the cell cycle and subsequently undergo apoptosis, as indicated by nuclear condensation and poly(ADP-ribose) polymerase cleavage. Following weekly i.v. treatment of PS-341 to mice bearing the PC-3 tumor, a significant decrease (60%) in tumor burden was observed in vivo. Direct injection of PS-341 into the tumor also caused a substantial (70%) decrease in tumor volume with 40% of the drug-treated mice having no detectable tumors at the end of the study. Studies also revealed that i.v. administration of PS-341 resulted in a rapid and widespread distribution of PS-341, with highest levels identified in the liver and gastrointestinal tract and lowest levels in the skin and muscle. Modest levels were found in the prostate, whereas there was no apparent penetration of the central nervous system. An assay to follow the biological activity of the PS-341 was established and used to determine temporal drug activity as well as its ability to penetrate tissues. As such, PS-341 was shown to penetrate PC-3 tumors and inhibit intracellular proteasome activity 1.0 h after i.v. dosing. These data illustrate that PS-341 not only reaches its biological target but has a direct effect on its biochemical target, the proteasome. Importantly, the data show that inhibition of this target site by PS-341 results in reduced tumor growth in murine tumor models. Together, the results highlight that the proteasome is a novel biochemical target and that inhibitors such as PS-341 represent a unique class of antitumor agents. PS-341 is currently under clinical evaluation for advanced cancers.
Algorithms↗
A randomized trial comparing 5-mg and 10-mg warfarin loading doses.
BACKGROUND: Warfarin sodium therapy is usually initiated with a loading dose to reduce the time required to elevate the international normalized ratio (INR). Warfarin loading doses are associated with early overanticoagulation and the development of a potential hypercoagulable state; they also may not hasten achieving an INR value between 2.0 and 3.0. This study was designed to prospectively confirm our observation that a 5-mg warfarin sodium loading dose is as effective as a 10-mg loading dose in achieving a therapeutic INR for 2 consecutive days on days 3 and 4 or 4 and 5 of therapy. METHODS: Fifty-three patients initiating warfarin therapy with a target INR of 2.0 to 3.0 were randomly allocated to receive an initial dose of 5 or 10 mg of warfarin. Subsequent doses were based on dosing algorithms. The INR was measured daily for 5 days. The primary end point of the study was the proportion of patients whose INR values were between 2.0 and 3.0 on 2 consecutive daily determinations on days 3, 4, or 5 of the study and whose INR did not exceed 3.0 at any point during the study. RESULTS: Five (24%) of 21 patients in the 10-mg group and 21 (66%) of 32 patients in the 5-mg group achieved the primary end point (relative risk 2.22, 95% confidence interval 1.30-3.70 [P < .003]). A trend toward less overanticoagulation was seen in the 5-mg warfarin group. CONCLUSION: A 10-mg loading dose of warfarin is unlikely to be more effective than a 5-mg loading dose in achieving an INR of 2.0 to 3.0 by day 4 or 5 of therapy.
Aged↗
Phenotypic characteristics of cell lines derived from disseminated cancer cells in bone marrow of patients with solid epithelial tumors: establishment of working models for human micrometastases.
Bone marrow (BM) is a clinically relevant site of micrometastatic disease in patients with solid epithelial tumors. It is, therefore, important to establish suitable models that allow the in-depth characterization of disseminated tumor cells present at low frequencies of 10(-5)-10(-6) nucleated BM cells. The aim of this study was to assess common phenotypic features of nine tumor cell lines established from BM of patients with cancer of the prostate (four cell lines), breast (two cell lines), lung (two cell lines), and colon (one cell line) using immunocytochemistry, flow cytometry, and reverse transcription-PCR. All cell lines stained positive for both cytokeratins, the epithelial intermediate filaments, and the epithelial cell adhesion molecule E-cadherin, and they lacked markers of BM-derived cells. The tumor origin of the cell lines was supported by the expression of the ErbB2 oncogene (seven of nine) and MAGE mRNA (eight of eight). All cell lines coexpressed cytokeratin and vimentin, the mesenchymal intermediate filament, indicating an epithelial-mesenchymal transition of micrometastatic cells. The invasive phenotype of the immortalized cells was also reflected by the consistent expression of several metastasis-associated adhesion molecules, including alpha5 (eight of nine), alpha6 (five of nine), alphaV (nine of nine), beta1 (nine of nine), and beta3 (nine of nine) integrin subunits and the Mr 67,000 laminin receptor (seven of nine). Contrary to our expectations, metastasis-promoting CD44 variant isoforms were only detected on two lines, whereas all cell lines expressed MUC18/melanoma cell adhesion molecule and intercellular adhesion molecule-1, two members of the immunoglobulin superfamily of adhesion molecules that are not frequently found on primary carcinoma cells. The consistent expression of various epithelial and tumor-associated antigens provides evidence that the established cell lines are derived from disseminated cancer cells present in the BM. The invasive phenotype of the immortalized cells was mirrored by their epithelial-mesenchymal transition and the expression of several metastasis-associated molecules, which might be potential candidates for novel therapeutic targets.
Biomarkers, Tumor↗
Effect of surgical adhesion reduction devices on the propagation of experimental intra-abdominal infection.
HYPOTHESIS: The use of certain surgical adhesion reduction devices where there is a risk of concomitant bacterial contamination potentiates intra-abdominal infection. DESIGN: Evaluation of adhesion reduction devices in an experimental model of intra-abdominal infection. SETTING: Experimental animal model. INTERVENTIONS: Adhesion reduction devices were administered at the time of bacterial challenge. MAIN OUTCOME MEASURES: Animal mortality rate, abscess formation, and bacterial counts in peritoneal fluid and blood cultures. RESULTS: The use of bioresorbable membrane adhesion reduction devices in the presence or absence of antibiotic therapy did not alter the disease process as compared with appropriate control groups. However, adhesion reduction gels prepared from sodium hyaluronate and carboxymethylcellulose chemically modified with carbodiimide or ferric ion complexed sodium hyaluronate increased the incidence of peritonitis in treated animals. Gel formulations containing diimide-modified carboxymethylcellulose did not have this effect. CONCLUSIONS: The use of certain adhesion reduction devices resulted in the propagation of intra-abdominal infection in an experimental rat model. This outcome was dependent on the composition of the device employed. The use of adhesion reduction devices should be tested in appropriate models of infection where there is the risk of concomitant bacterial contamination.
Abdominal Abscess↗
Cerebroside sulfate activator protein (Saposin B): chromatographic and electrospray mass spectrometric properties.
Cerebroside sulfate activator protein is a small, heat-stable protein that is exceptionally resistant to proteolytic attack. This protein is essential for the catabolism of cerebroside sulfate and several other glycosphingolipids. Protein purified from pig kidney and human urine was extensively characterized by reversed-phase liquid chromatography and electrospray mass spectrometry. These two sources revealed 20 and 18 different molecular isoforms of the protein, respectively. Plausible explanations of the structures of the majority of these isoforms can be made on the basis of accurate molecular mass assignments. The reversed-phase chromatographic and electrospray mass spectrometric properties of enzymatically deglycosylated and disulfide-reduced protein were also compared. In addition to a demonstration of the power of electrospray ionization mass spectrometry for revealing a wealth of information on protein microheterogeneity and structural detail, the results also demonstrate the utility of this technique for monitoring spontaneous chemical and enzymatically mediated changes that occur as a result of metabolic processing and protein purification.
Animals↗
Evaluation of a telerobotic system to assist surgeons in microsurgery.
A tool was developed that assists surgeons in manipulating surgical instruments more precisely than is possible manually. The tool is a telemanipulator that scales down the surgeon's hand motion and filters tremor in the motion. The signals measured from the surgeon's hand are transformed and used to drive a six-degrees-of-freedom robot to position the surgical instrument mounted on its tip. A pilot study comparing the performance of the telemanipulator system against manual instrument positioning was conducted at the University of Southern California School of Medicine. The results show that a telerobotic tool can improve the performance of a microsurgeon by increasing the precision with which he can position surgical instruments, but this is achieved at the cost of increased time in performing the task. We believe that this technology will extend the capabilities of microsurgeons and allow more surgeons to perform highly skilled procedures currently performed only by the best surgeons. It will also enable performance of new surgical procedures that are beyond the capabilities of even the most skilled surgeons.
Evaluation Studies as Topic↗
Expression and localization of PG-Lb/epiphycan during mouse development.
We have examined the expression pattern of the PG-Lb/epiphycan gene that encodes a small leucine-rich repeat proteoglycan during mouse embryonic development. PG-Lb/epiphycan mRNA transcripts were first detected at E12.5 days postcoitus (dpc) at high levels in structures that were developing cartilage elements. The gene is expressed in a very specific temporal and spatial fashion in cartilaginous structures. To examine PG-Lb/epiphycan gene expression during cartilage development in more detail, we performed in situ hybridization on hindlimb sections at specific stages of mouse embryonic development. The expression of PG-Lb/epiphycan was compared to that of collagen type II and collagen type X, which are early and late markers for cartilage development, respectively. The expression of PG-Lb/epiphycan occurs later than collagen type II in cartilage development, but its expression appears in the growth plate before and is excluded from the zone of hypertrophic chondrocytic cells expressing collagen type X. An antibody against PG-Lb/epiphycan localized the protein within the entire growth plate of the E17.5 dpc embryonic hindlimb cartilage including the hypertrophic zone where PG-Lb/epiphycan gene expression is turned off. Our results show that PG-Lb/epiphycan gene expression is an intermediate marker for chondrogenesis, and that the protein can be localized to the extracellular matrix surrounding resting, proliferating, and hypertrophic chondrocytes by immunofluorescence histochemistry.
Animals↗
Cytogenetic aspects of the Canadian early and mid-trimester amniotic fluid trial (CEMAT).
Cytogenetic results from a large multicentre randomized controlled study of 2108 amniotic fluids obtained at 11+0-12+6 weeks (EA) and 1999 fluids at 15+0-16+6 weeks (MA) were compared. There was no statistically significant difference in the rate of chromosome abnormalities (EA =1.9 per cent; MA=1.7 per cent) or level III mosaicism (EA=0.2 per cent; MA= 0.2 per cent) between the groups. Level I and Level II mosaicism occurred more frequently in MA. Maternal cell contamination was not significantly different between the groups, but maternal cells only were analysed from one bloody EA fluid. The number of repeat amniocenteses because of cytogenetic problems was 2.2 per cent in the EA group compared with only 0.3 per cent in the MA group. On average, culture of EA fluids required one day more than MA fluids. Although both culture success (97.7 per cent) and accuracy (99.8 per cent) were high for patients randomized to the EA group, routine amniocentesis prior to 13 weeks' gestation is not recommended for clinical reasons including an increased risk of fetal loss and talipes equinovarus.
Amniocentesis↗
Prevalence of elevated blood leads and exposure to lead in construction trades in Iowa and Illinois.
BACKGROUND: Despite lowering of the permissible exposure level for lead in construction from 200 to 50 microg/m3 in 1993, excessive lead exposure continues to be a problem. Relatively little data are available from the Midwestern U.S. on the environmental lead concentrations generated during various construction activities and the potential for worker exposure. This study characterized the prevalence of blood lead concentrations in high-risk construction trades in Iowa/Illinois, and identified risk factors for occupational exposure to lead in these construction workers. METHODS: A sample of 459 workers was selected from the total population of all union members from trade groups of painters, plumbers/pipefitters, ironworkers, laborers, and electricians. Participants completed an interviewer-administered questionnaire obtaining information on demographics, symptoms, occupational history, work practices, personal protective equipment, and training. Venous blood samples were collected from each participant and analyzed for blood lead (using atomic absorption spectroscopy) and free erythrocyte protoporphyrin levels. RESULTS: Blood lead levels (BLLs) of construction workers ranged from 0.1 to 50 microg/dL. Geometric mean blood lead concentrations by trade group were: laborers (7.6 microg/dL, n = 80); painters (5.9 microg/dL, n = 83); ironworkers (5.2 microg/dL, n = 87); plumbers (4.4 microg/dL, n = 82); electricians (2.4 microg/dL, n = 91). Blood lead levels for painters and laborers were significantly higher than other trade groups, and levels for electricians were significantly lower (p < 0. 01). Participants reported working primarily on commercial and industrial projects including new construction, renovation, and demolition. There were significant differences between the types of projects performed by different trade groups with laborers performing more highway/bridge renovation (p < 0.01), and plumbers reporting more residential remodeling (p = 0.05), repair of water lines containing lead (p = 0.04), or work on lead joints (p < 0.01). In addition to trade, elevated blood lead levels were associated with the type of construction project (especially bridge renovation and residential remodeling) and activities that include welding, cutting, rivet busting. The age of the home in which the worker lived, and hobbies such as casting/smelting lead for bullets or sinkers, were also important risk factors. Compliance with OSHA's Construction Lead Standard, and implementation of good occupational health and safety practices in general, was poor. CONCLUSIONS: Blood lead levels of 459 construction workers differed by the type of trade, type of project and specific job activity owing to differences in the inherent exposure potential of each task. Although the numbers of workers performing lead abatement projects were small, the trend for lower BLL in this group provides evidence that training, implementation of engineering controls, and proper use of personal protective equipment such as respirators is effective in controlling lead poisoning.
Adult↗
Heat shock protein 70 (Hsp70) stimulates proliferation and cytolytic activity of natural killer cells.
We previously demonstrated that lysis of tumor cells that express Hsp70, the highly stress-inducible member of the HSP70 family, on their plasma membrane is mediated by natural killer (NK) cells. Here, we studied the effects of different proteins of the HSP70 family in combination with interleukin 2 (IL-2) on the proliferation and cytotoxic activity of human NK cells in vitro. Proliferation of NK cells was significantly enhanced by human recombinant Hsp70 (rHsp70) and to a lesser extent by rHsp70homC, the recombinant C-terminal peptide-binding domain derived from Hsp70hom, but not by the constitutive Hsc70 or DnaK, the Escherichia coli analogue of human Hsp70. Even rHsp70 protein alone moderately enhances proliferation and cytolytic activity of NK cells, thus indicating that the stimulatory effect is not strictly dependent on IL-2. NK cells stimulated with rHsp70 protein also exhibit an increased secretion of interferon gamma (IFN-gamma). The phenotypic characterization of NK cells with specificity for Hsp70-expressing tumor cells revealed a CD16dim/CD56bright and increased CD57 and CD94 expression. The cytolytic activity of NK cells also was significantly reduced when a CD94-specific antibody or rHsp70 was added directly before the cytotoxicity assay, whereas other antibodies directed against CD57 and major histocompatibility complex class I molecules or Hsp70 proteins, including Hsc70 and DnaK, did not affect the NK-mediated killing. However, long-term incubation of NK cells with rHsp70 protein enhances not only the proliferative but also the cytolytic response against Hsp70-expressing tumor cells. Our results indicate that the C-terminal domain of Hsp70 protein affects not only the proliferative but also the cytolytic activity of a phenotypically distinct NK cell population with specificity for Hsp70-expressing tumor cells. 1999 International Society for Experimental Hematology.
Antibody Specificity↗
Somatostatin receptor subtype 2A expression in the rat retina.
Somatostatin is mainly expressed by sparsely occurring amacrine and interplexiform cells in the retina. In this study, we characterized the expression and cellular localization of one of the somatostatin subtype (sst) receptors, sst2A, in the rat retina. The presence of sst2A receptor messenger RNA in retinal extracts was demonstrated by reverse transcription-polymerase chain reaction using specific primers to detect the sst2 receptor and its isoforms, sst2A and sst2B. Specific sst2A receptor immunoreactivity was mainly localized to the plasma membrane of several neuronal cell types. In the outer retina, immunoreactivity was localized to cone photoreceptors, horizontal cells, and rod and cone bipolar cells. Double-label experiments showed the co-localization of sst2A receptor and protein kinase C (alpha and beta), a rod bipolar cell marker, and of sst2A receptor and Calbindin-D28k, a horizontal cell marker. In the inner retina, sst2A receptor immunoreactivity occurred in tyrosine hydroxylase-positive amacrine cells; most were of medium to large size. These findings indicate that somatostatin may act at a distance, in a paracrine manner, on several cell types that express the sst2A receptor, and therefore exert a broad modulatory influence on both scotopic and photopic visual pathways.
Animals↗
Relationship between coronary function by positron emission tomography and temporal changes in morphology by intravascular ultrasound (IVUS) in transplant recipients.
BACKGROUND: Transplant coronary vasculopathy is one of the major causes of graft failure and death in cardiac transplant recipients. A non-invasive test of coronary function to predict the course of this disease would be desirable. METHODS: To determine whether the degree of abnormalities in endothelial dependent coronary vasomotion (cold pressor testing) or endothelial independent vasodilatory capacity (intravenous dipyridamole) as determined by positron emission tomography (PET) one to two years after heart transplantation is correlated with the course of transplant vasculopathy. Nineteen patients had baseline PET and intravascular ultrasound studies (IVUS) at 18 +/- 6 months after cardiac transplantation and a follow up IVUS study 15 +/- 5 months later. RESULTS: Myocardial blood flow was higher in patients than in healthy controls (p < 0.002) but increased during cold pressor testing only in controls (p < 0.005). Myocardial blood flow normalized to the rate pressure product declined in patients (p < 0.001). Dipyridamole-induced hyperemic blood flow and the flow reserve normalized to the resting rate pressure product were lower in patients than in controls (p < 0.001 and p < 0.01). The normalized flow reserve was correlated with changes in total vessel area (r = 0.55; p = 0.02) and lumen diameter (r = 0.52; p < 0.05). CONCLUSION: These findings suggest that the degree of abnormalities in endothelial independent myocardial flow as detected by PET one to two years after transplantation is associated with morphological indices of disease progression by IVUS.
Cold Temperature↗
Protein-kinase-specific inhibitors block Langerhans' cell migration by inhibiting interleukin-1alpha release.
Previous studies have shown that depletion of Langerhans' cells (LC) from murine epidermis by the superantigen, staphylococcal enterotoxin A (SEA) involves interleukin-1alpha (IL-1alpha) and is inhibitable by agents that block G-protein-associated kinases. The purpose of this study was to determine whether specific kinase inhibitors block LC depletion by inhibiting IL-1alpha release and to ascertain whether LC depletion by SEA involves cell migration. These goals were addressed by measuring the IL-1alpha release within whole or LC-depleted epidermal cell suspensions in the presence of SEA and/or H-7 (an inhibitor of protein kinase C) or H-8 (an inhibitor of G-protein-associated kinases) and by examining the migration of cells with LC markers in SEA-treated skin sections. The results suggest that LC depletion by SEA involves migration and that this migration is blocked by protein kinase inhibitors, at least in part, through inhibition of SEA-induced IL-1alpha release by epidermal cells.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
Prenatal detection of cerebral lesions in a fetus with tuberous sclerosis.
We report a newborn, diagnosed prenatally with both cardiac rhabdomyomas and a brain tumor. To the best of our knowledge, this is the first report of central nervous system (CNS) lesions detected prenatally in a child with tuberous sclerosis with term follow-up. At 36 months, the child has normal growth and is developing appropriately. Thus the finding of CNS tumors on fetal ultrasound examination can help in the prenatal diagnosis of tuberous sclerosis but does not necessarily indicate a poor prognosis.
Adult↗
A randomized prospective trial of amphotericin B lipid emulsion versus dextrose colloidal solution in critically ill patients.
BACKGROUND: Amphotericin B is the agent of choice for most invasive fungal infections in critically ill patients. It is associated with at least a 50% incidence of nephrotoxicity, despite prophylactic measures such as sodium loading. Newer formulations of amphotericin B are available but are costly and have unknown bioavailability in critically ill patients. Previous trials in neutropenic and critically ill patients have demonstrated that mixing amphotericin B with 20% lipid solution (Intralipid; Clintec Nutrition, Deerfield, III) may decrease nephrotoxicity. METHODS: In this randomized, prospective clinical trial, patients with positive fungal blood cultures, tracheal/sputum cultures or peritoneal cavity cultures were randomized to receive either 0.5 mg/kg per day of amphotericin B dextrose or 1.0 mg/kg per day of amphotericin B lipid emulsion. Duration of therapy was determined by the primary care team. Weekly 24-hour creatinine clearance was measured until 2 weeks after amphotericin B therapy was completed. RESULTS: The two groups were similar based on age, white blood cell count, serum creatinine, and creatinine clearance at the beginning of therapy. The group receiving amphotericin B lipid emulsion had significantly less decrease in creatinine clearance compared with controls, despite receiving significantly more amphotericin B. CONCLUSION: Amphotericin B lipid emulsion can be given at a higher total cumulative dose than amphotericin B dextrose with less nephrotoxicity.
Adult↗
A lost piece of melanoma history.
The original descriptions of melanoma of the hand, foot, vulva, and metastatic melanoma to the heart and bowel were by Jean Cruveilhier in his Anatomie Pathologique du Corps Humains published between 1829 and 1842. Cruveilhier's descriptions predate publications currently ascribed as being the first case reports of these melanomas. Cruveilhier's atlas of pathology also contains the original descriptions of multiple sclerosis, hypertrophic pyloric stenosis, and gastric ulcers. Cruveilhier's work is well known to book collectors, but his melanoma discoveries have not been cited since Pemberton in 1858. Cruveilhier's case reports are reviewed in addition to a discussion of their significance and historical contexts. Current melanoma scholars will appreciate this lost piece of melanoma history with its early historical discoveries and magnificent illustrations.
Female↗