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J Arnold

Publications and source records attributed to J Arnold.

At least 145 records · Page 8Linked to original sources
PubMed1991

Inhibition of acute inflammation in the periphery by central action of salicylates.

Understanding of the antiinflammatory actions of nonsteroidal drugs is incomplete, but these actions are believed to occur in the periphery, without any contribution from the central nervous system. Recent research on the antipyretic antiinflammatory neuropeptide alpha-melanocyte-stimulating hormone indicates that it can act centrally to inhibit peripheral inflammation; this raises the possibility that other agents, such as nonsteroidal antiinflammatory drugs, may have similar activity. In the present research both lysine acetylsalicylate and sodium salicylate inhibited edema, induced in the mouse ear by topical application of picryl chloride, when injected into the lateral cerebral ventricle. This inhibitory activity on a measure of acute inflammation was not due to escape of the drugs into the periphery, because systemic injection of doses that were effective centrally did not affect inflammation. In contrast, central administration of a dose of indomethacin that was antiinflammatory when given intraperitoneally did not inhibit peripheral inflammation. Thus indomethacin apparently lacks the central antiinflammatory action of the salicylates. This observation, plus our inability to demonstrate either an antiinflammatory effect of intracerebroventricular dexamethasone, a prostaglandin inhibitor, or a pro-inflammatory influence of prostaglandin E2, suggests that prostaglandins are not important to central modulation of inflammation. The results indicate that, in addition to having central influences on fever and pain, salicylates can act within the brain to inhibit acute inflammation in the periphery.

Animals↗
PubMed1991

Continuous interleukin-2 and tumor-infiltrating lymphocytes as treatment of advanced melanoma. A national biotherapy study group trial.

Melanoma metastases were harvested from 82 patients for the purpose of growing and expanding tumor-infiltrating lymphocytes (TIL). Tumor tissue cell suspensions were incubated with interleukin-2 (IL-2), followed by repeated exposure to tumor antigen with or without OKT3 monoclonal antibody (MoAb). Initial growth success was achieved in 56 of 82 cultures (72%). Efforts were made to expand 26 of these 56 cultures for therapeutic TIL; 23 of 26 early cultures (88%) were successfully expanded for in vivo therapy. It took a mean of 78.5 +/- 25.4 days to grow sufficient TIL for treatment. Therapy included cyclophosphamide (1 g/m2) on day 1, followed by a 96-hour continuous infusion of IL-2 (18 x 10(6) IU/m2/d) on days 2 to 5, and approximately 10(11) (mean 1.49 +/- 0.93 x 10(11)) TIL on day 2. Patients who responded received monthly IL-2 as a 96-hour infusion. Median patient age was 45 years of age. Sixty-seven percent of the patients were men. Performance status was 0 to 1 in 77% of patients. Thirty-four percent of the patients had liver metastases. The usual IL-2 toxicities were seen. Response rate for 21 patients was 24% (95% confidence interval, 10% to 49%). One complete response was achieved with cells 98% CD4+; four partial responses were achieved with cells 80%, 94%, 98%, and 98% CD8+, respectively. Four of eight patients who received TIL, which had never been stimulated with OKT3, had tumor response. The authors conclude that a treatment plan for IL-2/TIL is technically difficult, costly, and effective for only a minority of patients. Overall, clinical results are not clearly superior to those obtained with other IL-2 regimens.

Adult↗
PubMed1991

Ubiquitin in health and disease.

Studies in recent years have shown that ubiquitin has increasingly important functions in eukaryotic cells; roles which were previously not suspected in healthy and diseased cells. The interplay between molecular pathological and molecular cell biological findings has indicated that ubiquitin may be pivotal in the cell stress response in chronic degenerative and viral diseases. Furthermore, the studies have led to the notion that ubiquitination may not only serve as a signal for nonlysosomal protein degradation but may be a unifying covalent protein modification for the major intracellular protein catabolic systems; these can act to identify proteins for cytosolic proteinases or direct intact and fragmented proteins into the lysosome system for breakdown to amino acids. This unifying role could explain why ubiquitin is restricted to eukaryotic cells, which possess extensive endomembrane systems in addition to a nuclear envelope. Protein ubiquitination is a feature of most filamentous inclusions and certain other intracellular conglomerates that are found in some degenerative and viral diseases. The detection of ubiquitin-protein conjugates is not of great diagnostic importance in these diseases. Protein ubiquitination is not only essential for the normal physiological turnover of proteins but appears to have been adapted as part of an intracellular surveillance system that can be activated by altered, damaged, or foreign proteins and organelles. The purpose of this system is to isolate and eliminate these noxious structures from the cell: as a cytoprotective mechanism this appears to have evolved in the cell akin perhaps to an 'intracellular immune system'. Other heat shock proteins such as hsp 70 may be involved in this process. It is apparent that ubiquitin has a role in embryonic development. Protein ubiquitination is presumably involved in the reorganisation of cytoplasm that accompanies cell differentiation. Ubiquitin is also necessary for the gross intracellular degradative processes which are consequent upon programmed cell death. Cell elimination is of key importance for a number of developmental morphogenetic changes. An understanding of the molecular details of these processes will no doubt provide further insights into the wide ranging roles of ubiquitin in the life process. As it says in the book 'Ubiquitin'; there is no doubt that ubiquitin is a 'lucky' protein. It is lucky in many ways: lucky for scientific progress, lucky for biomedical scientists and lucky for life! If you have not already done so, why don't you get lucky and look for a role for ubiquitin in your experimental system. As Avram Hershko has said "there is plenty to go round"!

Animals↗
PubMed1991

Chromosome-specific recombinant DNA libraries from the fungus Aspergillus nidulans.

Development of physical genomic maps is facilitated by identification of overlapping recombinant DNA clones containing long chromosomal DNA inserts. To simplify the analysis required to determine which clones in a genomic library overlap one another, we partitioned Aspergillus nidulans cosmid libraries into chromosome-specific subcollections. The eight A. nidulans chromosomes were resolved by pulsed field gel electrophoresis and hybridized to filter replicas of cosmid libraries. The subcollections obtained appeared to be representative of the chromosomes based on the correspondence between subcollection size and chromosome length. A sufficient number of clones was obtained in each chromosome-specific subcollection to predict the overlap and assembly of individual clones into a limited number of contiguous regions. This approach should be applicable to many organisms whose genomes can be resolved by pulsed field gel electrophoresis.

Aspergillus nidulans↗
PubMed1991

On the association of restriction fragment length polymorphisms across species boundaries.

We study the expected values of gametic-phase disequilibrium in both nuclear and cytonuclear systems in a finite population composed of reproductively isolated subpopulations. Random drift alone within each subpopulation will generate permanent overall non-zero gametic-phase disequilibrium in both a two-locus nuclear system and a cytonuclear system unless the population has an overall initial disequilibrium of zero. We derive formulae for the expected overall disequilibrium when mutation is involved and demonstrate that these values decay to zero at an extremely slow rate compared with the decay of the expected disequilibria within each subpopulation.

Animals↗
PubMed1991

Thyroglossal duct remnants. Preoperative evaluation and management.

Midline cervical cysts arising from the thyroglossal duct are one of the most common causes of anterior neck swelling in children. The potential for confusion between the thyroglossal duct cyst and the ectopic thyroid gland is well documented and may result in serious complications. A retrospective chart analysis was therefore undertaken to determine the relative importance of clinical evaluation, thyroid function testing, and radioisotope scanning in distinguishing these two entities preoperatively. A combined study was carried out by The Children's Hospital, Boston, Mass, and Rainbow Babies Hospital, Cleveland, Ohio. The hospital records, including nuclear scans, were reviewed. A total of 229 patients were taken to the operating room between January 1, 1978, and December 31, 1987. Nuclear scanning was performed in 30% of these patients. This subgroup of patients forms the basis for our guidelines of preoperative assessment. The absolute need for a preoperative scan is reexamined.

Adolescent↗
PubMed1991

The effects of admixture and population subdivision on cytonuclear disequilibria.

We examine the generation of cytonuclear disequilibria by admixture and continued gene flow. General formulas analogous to the nuclear case are first derived showing that the allelic and genotypic disequilibria from admixture or population subdivision equal their expected value across the contributing (sub) populations plus the covariance across these sources between the cytoplasmic gene frequency and the relevant nuclear frequency. A detailed study is then presented of the cytonuclear dynamics, in a random-mating population under two different migration scenarios. In both cases closed-form solutions are given for all variables as a function of the initial conditions and relevant migration parameters. The dynamics of the gene frequencies and allelic disequilibria, which dominate each system, are the same as those involving two unlinked nuclear loci, while the dynamics of the genotypic disequilibria and cytonuclear frequencies have no nuclear counterpart. The continent-island formulation focuses on a population receiving continued immigration from a large source of constant composition. A major discovery is that cytonuclear disequilibria can transiently build up on the "island" to levels far exceeding those found at equilibrium. In contrast, the admixture formulation focuses on the dynamics within two populations undergoing continued intermigration. Although in this case all cytonuclear associations must ultimately decay to zero, long-term transient disequilibria can develop which are many times their initial admixture values. For both migration scenarios it is shown that the time of population censusing relative to migration and reproduction dramatically affects both the amount and pattern of the nonrandom associations produced. The empirical relevance of these models is discussed in light of nuclear-mitochondrial data from a hybrid zone between European and North American eels and from a zone of racial admixture in humans.

Alleles↗
PubMed1991

Hepatic phosphofructokinase-1 activity and fructose 2,6-bisphosphate levels in patients with abdominal sepsis.

1. In sepsis various processes of carbohydrate metabolism, such as hepatic gluconeogenesis and glycolysis, are altered. Phosphofructokinase-1, a key glycolytic enzyme, is controlled in the long term via regulation of synthesis and degradation of the protein itself, while in the short term it is regulated by allosteric effectors, such as fructose 2,6-bisphosphate (the most potent). In the present study hepatic phosphofructokinase-1 activity as well as phosphofructokinase-2 activity and the concentration of fructose 2,6-bisphosphate were assayed to determine if they might contribute to the derangement of carbohydrate metabolism seen commonly in sepsis. 2. The levels of glycogen and fructose 2,6-bisphosphate and the activity of phosphofructokinase-1 and phosphofructokinase-2 were determined in hepatic biopsies obtained at laparotomy from six patients with and seven patients without abdominal septic foci. 3. A significant increase in plasma lactate concentration was observed in the septic patients, whereas no significant differences in tissue glycogen content or plasma glucose concentration were seen between the groups. 4. No significant change in plasma insulin concentration was observed. However, levels of the counter-regulatory hormones (glucagon, cortisol and adrenaline) were elevated in the septic patients. 5. A 60% decrease in hepatic phosphofructokinase-1 activity was seen in the septic patients. However, no significant changes in hepatic phosphofructokinase-2 activity and fructose 2,6-bisphosphate content were observed in the septic patients. 6. The present results demonstrate that the decrease in hepatic phosphofructokinase-1 activity occurring in sepsis does not appear to reflect alterations in the concentration of fructose 2,6-bisphosphate.

Abdomen↗
PubMed1991

Lipid infusion increases oxygen consumption similarly in septic and nonseptic patients.

This investigation compared the metabolic effects of lipid infusion in five septic and five nonseptic patients. Oxygen consumption was determined by indirect calorimetry over 1 h of rest and during 2 h when Intralipid (20%) was infused [166 mL/h; 23 kJ/min (5.5 kcal/min)]. Septic patients had a resting metabolic rate 17% higher than that of their nonseptic control subjects and a significant (P less than 0.05) rise (13%) in oxygen uptake was measured in both groups of subjects during the 2-h infusion of lipid. Preinfusion respiratory quotient (RQ) was 7% higher in the septic patients (P less than 0.05), and during the infusion period RQ decreased similarly (approximately 6%; P less than 0.05) in both groups. Plasma catecholamines were elevated in the septic patients preinfusion and the concentrations remained unaltered during the infusion. Norepinephrine rose significantly in the nonseptic group with the lipid infusion. The results show that sepsis has little or no influence on the characteristic rise in metabolic rate that occurs with intravenous lipid.

Adult↗
PubMed1991

Biliary secretion of bile acids, lipids, and bilirubin by the transplanted liver. A quantitative study in patients on cyclosporine.

To investigate biliary secretion in liver-transplanted patients on cyclosporine treatment we used duodenal perfusion with a nonabsorbable marker. After an overnight fast, 4 women and 5 men were studied for 6 hr at least 6 weeks after orthotopic liver transplantation. The data were compared with those obtained in 6 healthy controls. All transplanted patients received immunosuppressive therapy (corticosteroids, azathioprine, and cyclosporine). Biliary secretion rates of healthy controls were: bile acids 1.58 +/- 0.67 mmol/hr, phospholipids 0.27 +/- 0.11 mmol/hr, cholesterol 0.11 +/- 0.01 mmol/hr, and bilirubin 18 +/- 0.7 mumol/hr (mean +/- SEM). Liver-transplanted patients excreted 2.60 +/- 0.4 mmol/hr bile acids, 0.56 +/- 0.08 mmol/hr phospholipids, 0.18 +/- 0.04 mmol/hr cholesterol, and 22.0 +/- 4.5 mumol/hr bilirubin. Analysis of individual bile acids revealed that in the bile of liver transplant patients the percentage of cholic acid was elevated, whereas that of deoxycholic acid was reduced as compared with controls. These findings indicate that in the transplanted liver under immunosuppressive therapy with cyclosporine biliary secretion of bile acids, lipids, and bilirubin is not reduced.

Adult↗
PubMed1991

Clinical experience with heparin-coated cardiopulmonary bypass circuits.

The extensive area of contact between blood and synthetic surfaces during cardiopulmonary bypass results in the activation of the kallikrein, the complement and the clotting and fibrinolytic systems. This results in white cell activation and a whole body inflammatory response. Pulmonary neutrophil sequestration is also known to occur during cardiopulmonary bypass and has been associated with pulmonary damage. This has been previously demonstrated using the technique of differential neutrophil counts in simultaneous venous and left atrial samples. The efficacy of retinal fluorescein angiography as an indicator of cerebral microembolism has also been proved in previous studies. The objectives of this study were to determine whether heparin precoating with Duraflo II reduced pulmonary neutrophil sequestration, retinal microembolism and postoperative blood loss. Fourteen patients were randomized into two groups using either heparin-coated or nonheparin-coated cardiopulmonary bypass circuits. The preliminary results suggest a reduction in pulmonary neutrophil sequestration (p greater than 0.05) and the generation of thrombin antithrombin complexes (p less than 0.05). Retinal microembolism was not significantly different in the two groups nor was the postoperative blood loss. Thus, heparin-coated cardiopulmonary bypass circuits do not reduce pulmonary neutrophil sequestration, retinal microembolism or postoperative blood loss.

Biocompatible Materials↗
PubMed1991

Continuous interleukin-2 and lymphokine-activated killer cells for advanced cancer: a National Biotherapy Study Group trial.

We conducted a multicenter, phase II trial of continuous-infusion recombinant interleukin-2 (rIL-2) and lymphokine-activated killer (LAK) cells. Patients had advanced cancer, measurable disease, and a good performance level. Treatment included a 5-day continuous infusion of 18 x 10(6) IU/m2/d of rIL-2 followed by 1 day of rest, 4 days of leukapheresis to collect cells for in vitro augmentation of cellular cytotoxicity, and 5 more days of rIL-2 infusion with reinfusion of LAK cells for 3 successive days. Therapy was repeated after 2 weeks. There were 117 patients enrolled: 63% were males, with a median age of 51 years. Eighty-two percent were managed in oncology units, and 18% were in intensive care units. Six patients died within 1 month of initiating therapy. In renal cell carcinoma, the response rate was one of 31 patients (3%), with a median survival of 10.7 months. In melanoma, the response rate was four of 33 patients (12%), with a median survival of 6.1 months. For all other histologies, response rate was three of 53 patients (5%), with a median survival of 7.4 months. All responders were asymptomatic when therapy was initiated. This trial confirms the feasibility of administering continuous rIL-2 and LAK cells outside the intensive care unit environment. Antitumor activity in melanoma was similar to that seen in multicenter trials of bolus rIL-2 and LAK cells. Activity in renal cell cancer was disappointing.

Adolescent↗
PubMed1991

Pennsylvania's medically uninsured population: findings from a statewide survey.

Pennsylvania is currently considering legislative options to expand coverage and improve access to medical care for state residents who lack health insurance. Relevant data are presented from a telephone survey of 10,809 Pennsylvania households. Almost nine percent (8.5%) of the state's population lacks health insurance, representing over one million people. Those most likely to be uninsured are children and young adults, non-whites and the poor. A substantial number of poor people are not covered by the state's Medicaid program. The uninsured report poorer health status, more obstacled to receiving care and greater use of hospital services for primary care.

Adolescent↗
PubMed1991

Determinants of pharmacologic effects and toxicity of benzodiazepine hypnotics: role of lipophilicity and plasma elimination rates.

A recent consensus statement from the American Psychiatric Association emphasized that plasma elimination half-life should not be confused with duration of action and labeled use of short half-life, high-potency benzodiazepines as a risk factor for chronic toxicity, cognitive impairment, true physiologic dependence, and discontinuance symptoms. Instead, other factors such as lipid solubility (lipophilicity), brain clearance rate, redistribution rate, receptor kinetics, and tolerance are currently thought to be additional important determinants of the pharmacodynamic profile of benzodiazepines. In in vitro experiments, quazepam and its first metabolite, 2-oxoquazepam, were found to have high lipophilicity, a finding that could have important clinical implications.

Animals↗
PubMed1991

Compensatory mechanisms in platelet production: the response of Sl/Sld mice to 5-fluorouracil.

Sl/Sld mice are a unique animal model for studying platelet production in that they sustain normal platelet mass despite reduced marrow activity. The aim of this study was to determine if the compensatory mechanisms operating in these mice could be augmented by further reducing bone marrow activity with the drug 5-fluorouracil (5-FU), known to induce a strong stimulatory effect on platelet production. The platelet recovery in Sl/Sld mice after 5-FU administration contrasted that found in their normal littermates. Sl/Sld mice did not display the sustained thrombocytosis that was observed in +/+ mice between days 10 and 14. Platelet number was elevated in Sl/Sld mice at day 20, when the marrow megakaryocyte compartment had normalized. A significant increase in marrow megakaryocyte number and size was observed at days 8 and 11 in both +/+ and Sl/Sld mice after 5-FU administration. The data suggest that the increase in megakaryocyte size and number following 5-FU treatment was not able to significantly contribute to a sustained rebound thrombocytosis at the time of increased marrow megakaryocytopoiesis. It is concluded that the already compromised marrow of Sl/Sld mice is able to respond to the damage invoked by 5-FU to produce larger than normal megakaryocytes. In contrast to normal mice (+/+ littermates), the increase in marrow megakaryocytopoiesis observed does not lead to a thrombocytosis, indicating that platelet production and release in Sl/Sld mice cannot be further amplified by a strong marrow stimulation.

Anemia↗
PubMed1991

Hepatic interferon-alpha gene transcripts and products in liver specimens from acute and chronic hepatitis B virus infection.

In this study we have examined the localization of interferon-alpha in liver tissue from acute and chronic hepatitis B virus carriers to establish whether the defect in interferon-alpha production reported in chronic hepatitis B virus infection is at a pretranscriptional or posttranscriptional level using in situ hybridization and immunohistochemical techniques. Interferon-alpha messenger RNA transcripts and the immunoreactive protein were abundant in liver tissue and in particular in hepatocytes from patients with acute hepatitis B virus infection who subsequently recovered. In contrast interferon-alpha polypeptide was present in a significantly lower number of sinusoidal cells, mononuclear cells and hepatocytes in chronic hepatitis B virus carriers. Although a high proportion of patients with chronic hepatitis B virus infection had cells that expressed interferon-alpha messenger RNA transcripts, the number of such cells was significantly less than in acute hepatitis B virus infection, indicating that the defect in the hepatic interferon-alpha synthesis is at the level of gene activation. Furthermore, using double immunohistochemical staining, the number of hepatocytes containing HBcAg correlated inversely with the proportion of neighboring sinusoidal cells expressing interferon-alpha. These data support previous observations that interferon-alpha production is reduced in chronic hepatitis B virus infection and are consistent with the view that this cytokine is important in the clearance of the virus.

Acute Disease↗
PubMed1990

Recombinant interleukin-2 and adoptive immunotherapy alternated with dacarbazine therapy in melanoma: a National Biotherapy Study Group trial.

We evaluated adoptive cellular therapy with recombinant interleukin-2 (rIL-2) plus lymphokine-activated killer (LAK) cells alternating with sequential dacarbazine chemotherapy in 27 patients with metastatic melanoma. rIL-2 was given to the patients as a 5-day continuous-infusion priming cycle followed by 1 day of rest, 4 days of leukapheresis for in vitro LAK cell expansion, and then 4 1/2 days of continuous rIL-2 infusion in conjunction with reinfusion of LAK cells during the first 3 days of the continuous infusion. Two weeks later, patients received dacarbazine (1,200 mg/m2) chemotherapy. Two patients achieved complete remission, and five achieved a partial remission for a response rate of 26% (95% confidence interval = 12%-47%). Three patients had mixed responses. The partial and mixed responses were brief, ranging from 1 month to 6 months, whereas the two complete responses have been sustained for 13+ and 24+ months. There were no additive toxic effects except for thrombocytopenia, which delayed treatment in two patients. Alternating adoptive immunotherapy and dacarbazine chemotherapy appear to be reasonably tolerated by patients, but the response rate is not clearly better than that achieved with other rIL-2 regimens or with chemotherapy alone.

Adult↗