Biomedical subjects

J A Thompson

Publications and source records attributed to J A Thompson.

At least 91 records · Page 5Linked to original sources

PubMed1999

Small intestinal Na+,K+-adenosine triphosphatase activity and gene expression in experimental diabetes mellitus.

The Na+,K+-ATPase plays a key role in the absorption of electrolytes, water, and nutrients from the small intestine. The effect of streptozotocin-induced diabetes mellitus (STZ-DM) on the activity and expression of Na+,K+-ATPase in the rat small intestine was examined in the present study. Diabetes mellitus was induced by a single intraperitoneal injection of STZ (75 mg/kg) and control and STZ-DM rats were killed at day 30 (chronic diabetic state). Levels of Na+,K+-ATPase activity and numbers of sodium pumps were increased two- to threefold in the jejunum and ileum. Sodium pump kinetics were unaltered in STZ-DM. The levels of Na+,K+-ATPase alpha1 and beta1 isoform protein, corresponding mRNAs, and levels of transcription were increased in the jejunal and ileal mucosa of the chronically diabetic rat. The increases in Na+,K+-ATPase functional activity, protein expression, and mRNA were most marked at the level of the ileal mucosa. While a proximal to distal gradient in Na+,K+-ATPase activity and subunit isoform protein levels were observed in both control and diabetic rats, levels of subunit isoform mRNA abundance were similar in both regions of the small intestine in both groups of rats. The alterations in small intestinal Na+,K+-ATPase expression in the chronic diabetic state appear to involve alterations in transcriptional and posttranscriptional events and may likely represent an adaptive response that leads to increased Na+-coupled monosaccharide absorption in the context of a perceived state of nutrient depletion.

Animals↗

PubMed1999

Multicenter, randomized, phase III trial of CD8(+) tumor-infiltrating lymphocytes in combination with recombinant interleukin-2 in metastatic renal cell carcinoma.

PURPOSE: To prospectively evaluate in a multicenter randomized trial the antitumor activity of CD8(+) tumor-infiltrating lymphocytes (TILs) in combination with low-dose recombinant interleukin-2 (rIL-2), compared with rIL-2 alone, after radical nephrectomy in metastatic renal cell carcinoma patients. PATIENTS AND METHODS: Between December 1994 and March 1997, 178 patients with resectable primary tumors were enrolled at 29 centers in the United States and Europe. Patients underwent total nephrectomy, recovered, and were randomized to receive either CD8(+) TILs (5 x 10(7) to 3 x 10(10) cells intravenously, day 1) plus rIL-2 (one to four cycles: 5 x 10(6) IU/m(2) by continuous infusion daily for 4 days per week for 4 weeks) (TIL/rIL-2 group) or placebo cell infusion plus rIL-2 (identical regimen) (rIL-2 control group). Primary tumor specimens were cultured at a central cell-processing center in serum-free medium containing rIL-2 to generate TILs. RESULTS: Of 178 enrolled patients, 160 were randomized (TIL/rIL-2 group, n = 81; rIL-2 control group, n = 79). Twenty randomized patients received no treatment after nephrectomy because of surgical complications (four patients), operative mortality (two patients), or ineligibility for rIL-2 therapy (14 patients). Among 72 patients eligible for TIL/rIL-2 therapy, 33 (41%) received no TIL therapy because of an insufficient number of viable cells. Intent-to-treat analysis demonstrated objective response rates of 9.9% v 11.4% and 1-year survival rates of 55% v 47% in the TIL/rIL-2 and rIL-2 control groups, respectively. The study was terminated early for lack of efficacy as determined by the Data Safety Monitoring Board. CONCLUSION: Treatment with CD8(+) TILs did not improve response rate or survival in patients treated with low-dose rIL-2 after nephrectomy.

Adolescent↗

PubMed1999

Posterior tracheal wall perforation during percutaneous dilational tracheostomy: an investigation into its mechanism and prevention.

OBJECTIVES: Part 1: To describe the complication of posterior tracheal wall injury and perforation associated with the percutaneous dilational tracheostomy (PDT). Part 2: To determine the mechanism of posterior tracheal wall injury during PDT. DESIGN: Prospective observational study. SUBJECTS: Part 1: Medical-surgical ICU patients requiring tracheostomy. Part 2: Swine and cadaver models. INTERVENTIONS: Part 1: Consecutive medical-surgical ICU patients undergoing tracheostomy tube insertion via the percutaneous dilation technique with bronchoscopic guidance were enrolled in the study. Demographic data and complications were recorded. Part 2: Tracheostomy tubes were inserted via the percutaneous dilational technique in the swine model with concomitant bronchoscopic video recording from the proximal and distal airways. Tracheostomy tubes were inserted via the percutaneous dilational technique in the cadaver model followed by anatomic inspection of the airway. RESULTS: Part 1: Seven (29%) of 24 medical-surgical ICU patients sustained complications associated with PDT. Three patients (12.5%) sustained posterior tracheal wall perforations followed by the development of tension pneumothoraces. Part 2: The swine model demonstrated that posterior tracheal wall perforation may occur during PDT when the guiding catheter is withdrawn into the dilating catheters. Five-centimeter posterior tracheal wall mucosal lacerations occurred when the guidewire and the guiding catheter were not properly stabilized during PDT. CONCLUSION: Percutaneous dilational tracheostomy was associated with a 29% complication rate in this observational study. Of concern was the high rate (12.5%) of posterior tracheal wall perforation. The swine and cadaver models suggest that posterior tracheal wall injury or perforation may occur if the guidewire and guiding catheter are not properly stabilized. To avoid posterior tracheal wall injury, the guidewire and guiding catheter should be firmly stabilized during PDT.

Animals↗

PubMed1999

An unusual etiology of biliary hilar obstruction and the potential role of acidic fibroblast growth factor in the development of a biliary neuroma.

Neuroma of the biliary tract is a rare condition thought to be caused by trauma secondary to cholecystectomy. More rare is the occurrence that causes symptomatic biliary obstruction. A 65-year-old woman was hospitalized because of abdominal pain, nausea, vomiting, and general malaise of 1 to 2 months duration. Cholecystectomy had been performed 40 years before. Ultrasound revealed hepatomegaly and dilated intrahepatic ducts. CT showed intra- and extrahepatic ductal dilatation with questionable intraductal mass. Endoscopic retrograde cholangiopancreatography and percutaneous transhepatic cholangiography demonstrated stricture of the hepatic duct bifurcation. The biliary bifurcation was resected, and hepaticojejunostomy was performed. The patient's postoperative course was unremarkable. Histological examination of the surgical specimen revealed positive staining for the S-100 antigen of the obstructing luminal stricture (without evidence of cholangiocarcinoma), which was consistent with a biliary neuroma. Positive staining was also found for acidic (and not basic) fibroblast growth factor (FGF) and two of its high affinity receptors (FGFR-1 and FGFR-4). This study supports the apparent association between biliary neuromas and cholecystectomy as well as the potential role of an established angiogenic and neurogenic growth factor in the formation of this tumor. Finally, this case is also unique in that it represents the longest interval between cholecystectomy and presentation of a biliary neuroma, 40 years after surgery.

Aged↗

PubMed1998

Transcriptional activity of quinone methides derived from the tumor promoter butylated hydroxytoluene in HepG2 cells.

Butylated hydroxytoluene (BHT) is a pulmonary toxin and tumor promoter in mice presumably due to the formation of two quinone methides (QMs) that alkylate cellular nucleophiles. The activation of stress genes by these electrophilic metabolites was investigated with an assay system consisting of 14 recombinant cell lines derived from the human hepatoma line HepG2, each carrying a unique promoter or response element construct fused to the reporter gene for chloramphenicol acetyl transferase (CAT). The largest responses to QMs occurred in cells containing either the metallothionein IIA, glutathione S-transferase Ya, or 70 kDa heat shock protein promoter, or the xenobiotic response element. The other cell lines exhibited only small or no effects. These results are consistent with transcriptional activities reported for several other electrophiles known to undergo covalent interactions with proteins.

Butylated Hydroxytoluene↗

PubMed1998

Selective induction of apoptosis in mouse and human lung epithelial cell lines by the tert-butyl hydroxylated metabolite of butylated hydroxytoluene: a proposed role in tumor promotion.

Butylated hydroxytoluene (BHT) causes lung injury in mice and promotes tumor formation. Hydroxylation of a tert-butyl group on BHT to yield the metabolite, 6-tert-butyl-2-[2'-(2'-hydroxymethyl)-propyl]-4-methylphenol (BHTOH), may be required. BHTOH is more potent than BHT on an equimolar basis in causing lung damage, enhancing lung tumor development, killing isolated bronchiolar non-ciliated Clara cells, and inhibiting lung epithelial gap junctional intercellular communication. One mechanism proposed for tumor promoting agents is selective cytotoxicity; killing normal cells allows uninhibited clonal expansion of neighboring initiated cells. We compared the abilities of BHT, BHTOH, and other BHT metabolites to kill non-tumorigenic and tumorigenic mouse and human lung cell lines, and examined the contribution of apoptosis to this cytotoxicity. These cells lack the cytochrome P450 2B isozyme necessary for converting BHT to BHTOH. BHTOH and 4-hydroperoxy-4-methyl-2,6-di-tert-butyl-2,5-cyclohex-adienone+ ++ (BHTOOH) were most toxic, BHT and 2,6-di-tert-butyl-1,4-benzoquinone (BHTQu) were less potent, and 4-methyl BHT metabolites that are not pneumotoxic were ineffective. BHTOH most strongly induced apoptosis, based on nuclear condensation and transmission electron microscopy. Non-tumorigenic cells were as susceptible to cell death as the neoplastic cell lines when apoptosis and necrosis are not distinguished, but more sensitive to BHTOH-induced apoptosis. An apoptotic mechanism may underlie the lung tumor promoting actions of BHTOH.

Animals↗

PubMed1998

Enhancement of peroxynitrite-induced apoptosis in PC12 cells by fibroblast growth factor-1 and nerve growth factor requires p21Ras activation and is suppressed by Bcl-2.

Extracellular trophic factors can regulate whether cells subjected to oxidative stress will survive to proliferate or else undergo cell death. We have previously shown that about 35% of undifferentiated PC12 cells undergo apoptosis 18 h after exposure to peroxynitrite and that pretreatment with nerve growth factor (NGF) protects PC12 cells through activation of phosphatidylinositol (PI) 3-kinase. In contrast, pretreatment with acidic fibroblast growth factor (FGF-1) approximately doubled apoptosis. We report here that NGF added immediately after peroxynitrite treatment no longer protected against apoptosis, but instead enhanced apoptosis to the same extent as FGF. We further investigated which signaling pathways were involved in increasing the level of apoptosis. Overexpression of Bcl-2 blocked the increased apoptosis caused by NGF and FGF-1, but Bcl-2 did not prevent the induction of apoptosis by peroxynitrite alone. The increase in apoptosis caused by the trophic factors was also blocked by the expression of a dominant negative p21Ras mutant. Activation of PI 3-kinase by NGF pretreatment completely protected against both the enhanced apoptosis induced by FGF-1 pretreatment and NGF posttreatment and the apoptosis induced by peroxynitrite alone. Our results indicate that the enhancement of peroxynitrite-induced apoptosis caused by NGF and FGF-1 is dependent on the stimulation of a proapoptotic pathway involving p21Ras that can be suppressed by Bcl-2.

Animals↗

PubMed1998

Structural characterization of the covalent attachment of leukotriene A3 to leukotriene A4 hydrolase.

Leukotriene A4 (LTA4) hydrolase catalyzes the conversion of the unstable epoxide LTA4 [5(S)-trans-5,6-oxido-11,14-cis-eicosatetraenoic acid] into proinflammatory LTB4. During the process of catalyzing this reaction, the enzyme is suicide inactivated by its substrate. In addition, LTA3, and analogue of LTA4 that lacks the C14-C15 double bond, is a potent suicide inhibitor of LTA4 hydrolase. We have synthesized [3H]LTA3 and used this ligand to demonstrate that LTA3 can covalently label LTA4 hydrolase and that this labeling is specifically competed for by bestatin and LTA4. Incubation of recombinant human LTA4 hydrolase with LTA3 followed by proteolysis (endoproteinase Lys-C) resulted in a peptide map with a single modified peptide defining the location of the LTA3 covalent attachment region. This modified 21-amino-acid peptide had a UV absorption spectrum corresponding to a conjugated triene chromophore which established conservation of this structural unit after covalent interaction of LTA3 with LTA4 hydrolase. MALDI-TOF mass spectrometric analysis of the 21-amino-acid peptide adduct revealed an abundant MH+ at m/z 2658, consistent with the predicted nominal mass of the sequenced peptide with the addition of a single LTA3 moiety. Proteolysis of LTA4 hydrolase modified with LTA3 was performed sequentially with endo-Asp-N and endo-Lys-C. The resulting peptide isolated by reverse-phase high-performance liquid chromatography was analyzed by mass spectroscopy revealing two related peptides, D371-K385 (m/z 2018.0) and D375-K385 (m/z 1577.8), both of which retained the elements of LTA3. Postsource decay of m/z 1577.8 resulted in an abundant ion at m/z 536 and an ion of lesser abundance at m/z 856 consistent with cleavage between V381 and P382 that supported assignment of the modified tyrosine residue at Y383. These results suggest nucleophilic attack of a tyrosine residue (Y383) at the conjugated triene epoxide of LTA3 resulting in a triene ether carbinol covalent adduct.

Amino Acid Sequence↗

PubMed1998

Nitric oxide-dependent production of cGMP supports the survival of rat embryonic motor neurons cultured with brain-derived neurotrophic factor.

Trophic factor deprivation induces neuronal nitric oxide synthase (NOS) and apoptosis of rat embryonic motor neurons in culture. We report here that motor neurons constitutively express endothelial NOS that helps support the survival of motor neurons cultured with brain-derived neurotrophic factor (BDNF) by activating the nitric oxide-dependent soluble guanylate cyclase. Exposure of BDNF-treated motor neurons to nitro-L-arginine methyl ester (L-NAME) decreased cell survival 40-50% 24 hr after plating. Both low steady-state concentrations of exogenous nitric oxide (<0.1 microM) and cGMP analogs protected BDNF-treated motor neurons from death induced by L-NAME. Equivalent concentrations of cAMP analogs did not affect cell survival. Inhibition of nitric oxide-sensitive guanylate cyclase with 2 microM 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) reduced the survival of BDNF-treated motor neurons by 35%. cGMP analogs also protected from ODQ-induced motor neuron death, whereas exogenous nitric oxide did not. In all cases, cell death was prevented with caspase inhibitors. Our results suggest that nitric oxide-stimulated cGMP synthesis helps to prevent apoptosis in BDNF-treated motor neurons.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1998

Glutathione depletion associated with the HIV-1 TAT protein mediates the extracellular appearance of acidic fibroblast growth factor.

Primary murine embryonic fibroblasts transfected with HIV-1 TAT demonstrated decreased levels of high energy phosphates (ATP, GTP, UTP/CTP), adenine nucleotides (ATP, ADP, AMP), and both NAD+/NADH redox pairs, resulting in a substantial loss of redox poise. A greater than 50% decrease in intracellular reduced glutathione (GSH) concentration was accompanied by the extracellular appearance of acidic fibroblast growth factor (FGF-1). Addition of either N-acetyl-L-cysteine or glutathione ester (GSE), but not L-2-oxothiazolidine 4-carboxylate, partially restored intracellular GSH levels and resulted in loss of extracellular FGF-1. Treatment of FGF-1-transduced cells with buthionine sulfoximine (BSO) resulted in a time- and dose-dependent decrease in total cellular GSH concentration that was accompanied by the extracellular appearance of FGF-1. Inclusion of GSE during BSO treatment eliminated the extracellular appearance of FGF-1. BSO treatment of cells transfected with a mutant form of FGF-1, in which all three cysteine residues were replaced with serines, also decreased total cellular GSH concentration but failed to induce the extracellular appearance of FGF-1. Collectively, these results suggest that HIV-1 TAT induces a condition of oxidative stress, which mediates cellular secretion of FGF-1, an observation relevant to the pathophysiologic development and progression of AIDS-associated Kaposi's sarcoma.

Acetylcysteine↗

PubMed1998

Peroxynitrite-mediated inactivation of manganese superoxide dismutase involves nitration and oxidation of critical tyrosine residues.

Previous studies from our laboratory have demonstrated that the mitochondrial protein manganese superoxide dismutase is inactivated, tyrosine nitrated, and present as higher molecular mass species during human renal allograft rejection. To elucidate mechanisms whereby tyrosine modifications might result in loss of enzymatic activity and altered structure, the effects of specific biological oxidants on recombinant human manganese superoxide dismutase in vitro have been evaluated. Hydrogen peroxide or nitric oxide had no effect on enzymatic activity, tyrosine modification, or electrophoretic mobility. Exposure to either hypochlorous acid or tetranitromethane (pH 6) inhibited (approximately 50%) enzymatic activity and induced the formation of dityrosine and higher mass species. Treatment with tetranitromethane (pH 8) inhibited enzymatic activity 67% and induced the formation of nitrotyrosine. In contrast, peroxynitrite completely inhibited enzymatic activity and induced formation of both nitrotyrosine and dityrosine along with higher molecular mass species. Combination of real-time spectral analysis and electrospray mass spectroscopy revealed that only three (Y34, Y45, and Y193) of the nine total tyrosine residues in manganese superoxide dismutase were nitrated by peroxynitrite. Inspection of X-ray crystallographic data suggested that neighboring glutamate residues associated with two of these tyrosines may promote targeted nitration by peroxynitrite. Tyr34, which is present in the active site, appeared to be the most susceptible residue to peroxynitrite-mediated nitration. Collectively, these observations are consistent with previous results using chronically rejecting human renal allografts and provide a compelling argument supporting the involvement of peroxynitrite during this pathophysiologic condition.

Crystallography, X-Ray↗

PubMed1998

Ventriculoatrial conduction metrics for classification of ventricular tachycardia with 1:1 retrograde conduction in dual-chamber sensing implantable cardioverter defibrillators.

The introduction of dual-chamber sensing in implantable cardioverter defibrillators (ICDs) has greatly reduced the incidence of false detection due to supraventricular tachycardias. The remaining arrhythmias which serve to confound classification are supraventricular tachycardias (SVTs) with 1:1 anterograde conduction and ventricular tachycardias (VT) with 1:1 retrograde conduction. An algorithm has been designed and tested (28 patients) which employs ventriculoatrial (VA) conduction measurements to separate 1:1 VTs from 1:1 SVTs. A study was conducted to assess realistic VA interval boundaries for classification of arrhythmias with 1:1 retrograde atrial conduction. Intracardiac atrial and ventricular recordings of 7 passages of VT with retrograde conduction, 12 passages of atrioventricular nodal reentrant tachycardia (AVNRT), 3 passages of atrial tachycardia (AT), 8 passages of sinus tachycardia (ST), and 2 passages of orthodromic reentrant tachycardia (ORT) were analyzed. Automated real-time atrial and ventricular waveform recognition was performed on each passage and VA intervals were measured. Separation of VT with retrograde conduction from other 1:1 supraventricular tachycardias was effected by imposing discrete VA interval boundaries. VA boundaries of 80 ms to 234 ms classified 1:1 VT with 100% sensitivity (SENS) and 80% specificity (SPEC). In addition, the lower boundary completely classified AVNRT with 100% SENS and 100% SPEC, and all passages of ST were contained above the upper boundary. These findings could be of importance in algorithms for next-generation implantable cardioverter defibrillators which include two-chamber (atrial and ventricular) sensing and two-chamber interval measurements.

Algorithms↗

PubMed1998

Factors affecting pregnancy rates following laparoscopic insemination of 28,447 Merino ewes under commercial conditions: a survey.

The results of laparoscopic insemination of 28,447 Australian Merino ewes with semen from 468 rams were used to study factors influencing pregnancy. The overall pregnancy rate was 71.7% (20,423/28,447). Pregnancy rates varied with type of progestagen implant, type and dosage of PMSG, fresh or frozen semen, wool type and number of ewes inseminated per hour. The pregnancy rate (64.6%) obtained with Medroxy-progesterone acetate (MAP) sponges, was significantly (P < 0.01) lower than with Fluorogestone acetate 30 mg (FGA 30; 74.7%) sponges, Fluorogestone acetate 40 mg (FGA 40; 72.1%) sponges, and Controlled Internal Drug Release (CIDR-G; 71.7%) implants. A PMSG dose of 200 IU resulted in significantly (P < 0.05) lower pregnancy rates (62.4%) compared with 250 IU (72.9%), 300 IU (79.1%) and > or = 375 IU (69.4%). The mean pregnancy rate for ewes administered Folligon PMSG was 71.9%, which was significantly higher (P < 0.001) than that of ewes treated with Pregnecol PMSG (65.8%). The use of Pregnecol PMSG and MAP sponges was associated, and thus their conditional effects could not be calculated. Ewes inseminated with fresh semen were significantly (P < 0.001) more likely to become pregnant (82.2%) than those inseminated with semen frozen in pellets (69.5%) or straws (71.6%). Ewes inseminated during the months of March, April or May (fall, 71.5%) were just as likely to become pregnant as those ewes inseminated in November, December, January or February (69.6%). Significantly (P < 0.05) fewer strong wool ewes become pregnant to laparoscopic AI, (67.6%) than fine (71.7%), fine medium (73%) or medium wool ewes. Significantly (P < 0.0001) more pregnancies (77.6%) were achieved when more than 55 ewes were inseminated per hour compared with fewer than 35 ewes per hour (63.4%).

Animals↗

PubMed1998

Bacteriology of preserved stallion semen and antibiotics in semen extenders.

Three experiments were conducted to evaluate the effects of different antibiotics in a milk-glucose semen extender on motility of equine sperm and elimination of bacteria following storage of extended semen in vitro. In Experiment 1, 7 antibiotics were compared: amikacin, gentamicin, streptomycin, potassium penicillin, sodium penicillin, ticarcillin, and polymixin B. In Experiment 2, 3 antibiotic treatments were compared: potassium penicillin G, amikacin, or a combination of potassium penicillin G and amikacin. In Experiment 3, 3 antibiotic treatments were compared: potassium penicillin G-amikacin, ceptiofur, and a combination of ticarcillin and clavulanic acid (Timentin). Control treatments (antibiotic-free extender) were included in each experiment. Six motility variables were evaluated: percentage of motile sperm; percentage of progressively-motile sperm; percentage of rapidly-motile sperm; mean curvilinear velocity; mean average path velocity; and mean straight-line velocity. In Experiment 1, mean percentages of motile, progressively motile and rapidly motile sperm were lower (P < 0.05) in semen exposed to polymixin B then in other treatments. Mean average-path velocity of sperm in extender containing polymixin B was lower (P < 0.05) than that of all other treatments, with exception of control or ticarcillin. Mean straight-line velocity of sperm in extender containing polymixin B was lower (P < 0.05) than that of all other treatments, with exception of control, streptomycin or ticarcillin. Semen samples containing gentamicin, amikacin, streptomycin, or potassium penicillin were more effective (P < 0.05) at eliminating bacterial growth than those samples containing polymixin B. Semen samples containing gentamicin were also more effective (P < 0.05) at eliminating bacterial growth than those samples containing ticarcillin or sodium penicillin. In Experiment 2, mean percentage of rapidly-motile sperm, and mean curvilinear, average-path, and straight-line velocities were greater (P < 0.05) for potassium penicillin-amikacin than values for all other treatments. In 2 of 3 stallions, an effect of treatment on percentage of motile sperm was detected (P < 0.05). For one stallion, mean motility of potassium penicillin-amikacin was greater (P < 0.05) than that of all other treatment groups. For another stallion, mean motility of the control was lower (P < 0.05) than that of the other treatments. Following storage, potassium penicillin (16/18 [89%]) or potassium penicillin-amikacin (17/19 [94%]) were more effective (P < 0.05) at controlling aerobic and anaerobic bacterial isolates in semen specimens than was amikacin (10/18 [56%]). In Experiment 3, a difference among treatment groups for motility variables was not detected (P < 0.05). No bacterial growth was recovered in antibiotic-treated semen, with exception of Micrococcus sp. (2 colonies) which were isolated from one semen specimen treated with ceptiofur.

Amikacin↗

PubMed1998

Phase II trial of recombinant human interleukin-4 in patients with disseminated malignant melanoma: a Southwest Oncology Group study.

Malignant melanoma is increasing in incidence in this country. Metastatic disease generally responds poorly to most chemotherapy drugs. Immunologic and biologic agents have shown some activity in this disease. Interleukin 4 (IL-4) is a cytokine produced by activated T-lymphocytes with pluripotent activities including growth inhibition of various tumor cell lines in vitro and immune- mediated tumor growth inhibition in in vivo animal tumor models. In this phase II trial, patients with advanced malignant melanoma with no prior systemic therapy for metastatic disease and Southwest Oncology Group performance status 0-1 were treated with recombinant human IL-4 at a dose of 5 micrograms/kg/day by daily subcutaneous injection days 1-28 followed by a 7-day rest period, after which the cycle was repeated. Thirty-six patients were registered to this study. Two patients were ineligible by study criteria. Among the 34 eligible patients, there was 1 complete response, 0 partial responses, 2 stable/no responses, 27 increasing disease/progression, 1 early death, and 3 patients whose assessment was inadequate to determine response. The overall estimated response rate was 3% (1 of 34) with a 95% confidence interval 0.1-15%. The duration of the complete response is 421+ days. Thirty-one of the 34 eligible patients have died. The estimated median survival is 6 months (95% confidence interval 4-9 months). The most common toxicities were elevated liver function tests, nausea/vomiting/diarrhea, malaise/fatigue, edema, headache, myalgias/arthralgias, and fever/chills. Despite promising preclinical growth inhibitory and immunomodulatory effects, IL-4 in this dose and schedule showed only low antitumor activity. Alternative methods and routes of administration or combinations of IL-4 with other cytokines might produce greater antitumor effects.

Adult↗

PubMed1997

Influence of quinone methide reactivity on the alkylation of thiol and amino groups in proteins: studies utilizing amino acid and peptide models.

Quinone methides (QMs) are electrophiles formed in several biological processes including direct oxidations of 4-alkylphenols by cytochromes P450. These species may be responsible for the adverse effects of certain phenolic compounds through protein alkylation, but little information is available concerning specific targets or the resulting mechanisms of cell injury. The present goal was to determine the most likely sites of adduct formation among competing protein nucleophiles utilizing QMs of varying electrophilicity. Reactions of poorly reactive, moderately reactive, and highly reactive QMs, 2,6-di-tert-butyl-4-methylene-2,5-cyclohexadienone (BHT-QM), 6-tert-butyl-2-(2'-hydroxyl-1',1'-dimethylethyl)-4-methylene- 2,5-cyclohexadienone (BHTOH-QM), and 2-tert-butyl-6-methyl-4-methylene-2,5-cyclohexadienone (BDMP-QM), respectively, were investigated in aqueous solutions with nucleophilic amino acids. Each QM rapidly formed a thioether derivative of cysteine with little or no competition from the addition of water (hydration). The alpha-amino groups were the primary sites of alkylation for all other amino acids examined including lysine, histidine, tyrosine, and serine, and the pseudo-first order rates were 5 to 8-fold greater than the rates of hydration. Alkylation of the side chain nitrogens of lysine and histidine occurred at about one-fourth the rate of hydration for BDMP-QM, but no reaction was detectable for BHT-QM and no reactions occurred between QMs and amino acid hydroxyl groups. The results indicate that, based on chemical reactivity, peptide alkylation should occur in the order cysteine thiol > N-terminal amino > N epsilon-lysine = NIm-histidine, with side chain modifications occurring only with the more electrophilic QMs. Reactions of QMs with the tripeptide Gly-His-Lys confirmed the results with amino acids as N alpha-glycine alkylation predominated, but side chain adducts also formed with BHTOH-QM and BDMP-QM. Human hemoglobin was treated with QMs, hydrolyzed, and assayed by HPLC-thermospray mass spectrometry. This work revealed that N epsilon-lysine was the main alkylation site, emphasizing the importance of factors, in addition to chemical reactivity, which influence protein modification by electrophiles.

Alkylation↗

PubMed1997

Expression of transgenic carcinoembryonic antigen (CEA) in tumor-prone mice: an animal model for CEA-directed tumor immunotherapy.

Carcinoembryonic antigen (CEA) is a tumor marker for the most common forms of adenocarcinomas. We have previously described C57BL/6 mice transgenic for the complete human CEA gene. Compared with humans, these mice reveal a conserved spatiotemporal CEA expression pattern. To establish animal models for CEA-targeted tumor immunotherapy, we have crossed CEA transgenic mice with mice that are genetically predisposed to tumor development. These immunocompetent animals should allow optimization of immunotherapy strategies for maximal destruction of tumor tissues with minimal damage to CEA-expressing normal tissues. To develop a breast tumor model, CEA transgenic mice were cross-bred with mice transgenic for the rat neu protooncogene controlled by the mouse mammary tumor virus long terminal repeat. Female offspring developed poorly differentiated breast tumors, none of which, however, expressed CEA. As a model for colorectal tumors, mice bearing a mutation in the Apc gene (Min mice) and the CEA transgene developed multiple intestinal adenomas with strong CEA expression in all tumor cells. CEA expression had no significant effect on tumor growth. Occasional, well-differentiated breast adenocarcinomas in female offspring expressed CEA focally in tumor cells lining pseudolumina. Cross-breeding Apc(Min/+) mice with neu transgenic mice did not reveal a synergistic effect on the kinetics of breast tumor formation. Finally, CEA transgenic mice crossbred with mice transgenic for the SV40 large T antigen regulated by the surfactant protein-C promoter, developed multiple lung adenocarcinomas that revealed a mosaic CEA expression pattern.

Adenocarcinoma↗

PubMed1997

Free and protein-associated nitrotyrosine formation following rat liver preservation and transplantation.

Nitrotyrosine in human and animal tissues has been associated with pathologic conditions such as atherosclerosis, renal failure, and acute lung disease. In this study, free and protein-associated nitrotyrosine were determined in plasma and tissue samples using a dual-channel electrochemical detection method. Free nitrotyrosine was quantified in acetonitrile-extracted samples while protein-associated nitrotyrosine was determined in proteinase K-digested samples. In human plasma, total nitrotyrosine increased from 2.3 to 4.3 and 13.2 mumol/mol Tyr following addition of 0, 0.5, and 1 mM ONOO-. To determine if nitrotyrosine was produced during ex vivo hypothermic preservation, rat livers were stored in University of Wisconsin solution (UW) for 0, 6, or 8 h and reperfused for 3 h. Total nitro-tyrosine increased 359 and 908% after 6 and 8 h preservation compared to 0 h. To determine if nitrotyrosine was produced in vivo following hepatic ischemia, a rat preservation-transplantation model was utilized in which livers were flushed with cold UW (0-h group) or transplanted following 6 h hypothermic preservation in UW. Free nitrotyrosine increased from 15.7 +/- 0.3 in the 0-h group to 23.6 +/- 2.5 mumol/mol Tyr, 24 h posttransplant of 6-h preserved livers. Protein-associated nitrotyrosine increased from 9.5 +/- 1.1 in the 0-h group to 27.5 +/- 0.7 mumol/mol Tyr in the 6-h preservation-transplantation group. Protein-associated nitrotyrosine provides an integrative determination of nitration. Detection of free and protein-associated nitrotyrosine in biologic samples may allow insight into the role of .NO-derived oxidants in tissue injury associated with various pathologic conditions.

Animals↗