Determination of an optimal dosing schedule for combining Irinophore C™ and temozolomide in an orthotopic model of glioblastoma.

Our laboratory reported that Irinophore C™ (IrC™; a lipid-based nanoparticulate formulation of irinotecan) is effective against an orthotopic model of glioblastoma (GBM) and that treatment with IrC™ was associated with vascular normalization within the tumor. Here, the therapeutic effects of IrC™ when used in combination with temozolomide (TMZ) in concurrent and sequential treatment schedules were tested. It was anticipated that IrC™ engendered vascular normalization would increase the delivery of TMZ to the tumor and that this would be reflected by improved treatment outcomes. The approach compared equally efficacious doses of irinotecan (IRN; 50 mg/kg) and IrC™ (25 mg/kg) in order to determine if there was a unique advantage achieved when combining TMZ with IrC™. The TMZ sensitive U251MG(O) cell line (null expression of O-6-methylguanine-DNA methyltransferase (MGMT)) modified to express the fluorescent protein mKate2 was inoculated orthotopically into NOD.CB17-SCID mice and treatment was initiated 14 days later. Our results demonstrated that IrC™ and TMZ administered concurrently resulted in optimal treatment outcomes, with 50% long term survivors (>180 days) in comparison to 17% long term survivors in animals treated with IRN and TMZ or TMZ alone. Indeed, the different treatments resulted in a 353%, 222% and 280% increase in median survival time (MST) compared to untreated animals for, respectively, IrC™ combined with TMZ, IRN combined with TMZ, and TMZ alone. When TMZ was administered after completion of IRN or IrC™ dosing, an increase in median survival time of 167-174% was observed compared to untreated animals and of 67% and 74%, respectively, when IRN (50 mg/kg) and IrC™ (25mg/kg) were given as single agents. We confirmed in these studies that after completion of the Q7D×3 dosing of IrC™, but not IRN, the tumor-associated vascular was normalized as compared to untreated tumors. Specifically, reductions in the fraction of collagen IV-free CD31 staining (p<0.05) and reductions in tumor vessel diameter were observed in tumors from IrC™-treated animals when compared to tumors from untreated or IRN treated animals. Analysis by transmission electron microscopy of the ultra-structure of tumors from IrC™-treated and untreated animals revealed that tumor-associated vessels from treated animals were smaller, more organized and exhibited a morphology comparable to normal blood vessels. In conclusion, optimal treatment outcomes were achieved when IrC™ and TMZ were administered concurrently, whereas IrC™ followed by TMZ treatment given sequentially did not confer any therapeutic advantage.

Dietary intake in head and neck irradiated patients with permanent dry mouth symptoms.

Radiotherapy of the head and neck region, which includes the major and minor salivary glands in the radiation field, usually leads to temporary or permanent xerostomia. This may affect eating and increase the risk of inadequate intake of energy and nutrients. The aim of the present study was to investigate the effects of radiotherapy-induced xerostomia on energy and nutrient intake in individuals treated for malignancies in the head and neck region. The dietary intake of 24 patients with a low chewing stimulated whole saliva flow rate (< 0.5 ml/min) and in age and sex matched controls with normal flow rate (> 1.0 ml/min) was recorded for 7 days. The average daily energy intake was nearly 300 kcal lower in the irradiated patients with dry mouth symptoms than in the control group. The mean intake in the former group was 1925 kcal per day whereas the control group had an intake of 2219 kcal per day. Irradiated patients with dry mouth symptoms had significantly lower mean intakes of vitamin A, beta-carotene, vitamin E, vitamin B6, folacine, iron and zinc than those in the control group. There was also a lower intake of vitamin C, but this was not statistically significant. The intake of vitamins A and C exceeded or reached the levels recommended in the Swedish Nutritional recommendations, but the average intakes of fibre, iron, beta-carotene, vitamin E, zinc, selenium, and iron did not reach recommended levels, in neither the experimental nor the control group. There was a slight positive correlation between energy intake and saliva secretion rate in the control group, but the energy intake was totally independent of variations in secretion rate in the irradiated patients with low secretion rate.

Fever and respiratory symptoms after welding on painted steel.

Electric-arc welding generates particles and gases that can induce chronic bronchitis and airway obstruction. In this case report two welders are described who had fever, spirometric deterioration, and bronchial hyperreactivity after welding steel painted with chloro-containing polymer lacquer. Pyrolysis of this paint releases many different compounds, for example, hydrogen chloride and complex chlorinated compounds.

High- and low-affinity [3H]desipramine-binding sites in human postmortem brain tissue.

The binding of [3H]desipramine to human brain tissue was characterized. Competition studies in the frontal cortex and hypothalamus revealed a single-site binding model for noradrenaline (Ki 120-190 microM). The noradrenaline uptake inhibitors nisoxetine, nortriptyline and desipramine fitted two-site binding models and these compounds exhibited 10-80 times lower Ki values than the serotonin uptake inhibitor citalopram. The high-affinity component of the nisoxetine-sensitive [3H]desipramine binding (Ki 50-110 nM) approximated the binding sensitive to noradrenaline. This binding fraction was defined as that sensitive to 1 microM nisoxetine and showed a maximum binding capacity (Bmax) of 380 +/- 80 fmol/mg protein and an apparent Kd of 5.1 (4.5-5.7) nM in the hypothalamus. The binding was also investigated in 25 additional brain regions without finding detectable amounts of binding. However, when the specific binding was defined as that sensitive to 100 microM nisoxetine, low-affinity binding where Bmax and Kd were not possible to determine was obtained in all brain regions investigated. It is concluded that [3H]desipramine binding to human brain tissue represents multiple binding sites. Only when regarding binding sensitive to noradrenaline and to the high-affinity component of noradrenaline uptake inhibitors is the binding saturable and of high affinity. It is possible that this site represents the uptake site for noradrenaline.

The medical assistant: your partner in professionalism.

We encourage you to invest in your professional health care team by providing them the opportunity to improve their skills through educational programs presented by the ASMA. It is an investment which will pay dividends in the quality and professionalism of care for your patients. May we also encourage you to invest in giving your staff the opportunity to become members of ASMA? We will be happy to discuss the organization with you of any member of your staff at anytime.

High affinity [3H]paroxetine binding to serotonin uptake sites in human brain tissue.

[3H]Paroxetine binding to human brain tissue was characterized. Competition studies in the putamen and frontal cortex revealed single-site binding models for binding sensitive to 5-hydroxytryptamine (5-HT) (Ki 1-3 microM) and citalopram (Ki 0.6 nM), which displaced the same amount of binding. However, desipramine, norzimeldine and fluoxetine displaced additional binding (10-20%) and these competitors fitted two-site binding models with high affinity components in the nanomolar range and low affinity components in the micromolar range. The high affinity components approximated the 5-HT- and citalopram-sensitive binding fraction. Most of the [3H]paroxetine binding sites were protease-sensitive, but the low-affinity (microM) sites appeared to be protease-resistant. Based on these findings, only the [3H]paroxetine binding representing the fraction sensitive to 30 microM 5-HT (or e.g. 0.3 microM norzimeldine), was regarded as specific binding. This binding fraction was saturable with an apparent binding affinity (Kd) of 0.03-0.05 nM throughout the brain. The highest binding densities were obtained in the hypothalamus and substantia nigra (Bmax 500 fmol/mg protein). The basal ganglia reached intermediate densities (Bmax 200 fmol/mg protein), whereas cortical areas had low Bmax values (less than 100 fmol/mg protein). The lowest B max value was noted in cerebellar cortex (30 fmol/mg protein). The [3H]paroxetine binding was competitively inhibited by low concentrations of 5-HT, imipramine and norzimeldine, suggesting that the substrate recognition site for 5-HT uptake was labeled. Compounds active at dopaminergic, noradrenergic, histaminergic, 5-HT1, 5-HT2 and cholinergic muscarinic sites did not affect the binding at 100 microM concentrations. It is concluded that [3H]paroxetine is a marker for the 5-HT uptake site in the human brain, provided that an adequate pharmacological definition of specific binding is performed.

[3H]desipramine binding to rat brain tissue: binding to both noradrenaline uptake sites and sites not related to noradrenaline neurons.

The pharmacological and biochemical characteristics of [3H]desipramine binding to rat brain tissue were investigated. Competition studies with noradrenaline, nisoxetine, nortriptyline, and desipramine suggested the presence of more than one [3H]desipramine binding site. Most of the noradrenaline-sensitive binding represented a high-affinity site, and this site appeared to be the same as the high-affinity site of nisoxetine-sensitive binding. The [3H]desipramine binding sites were abolished by protease treatment, a result suggesting that the binding sites are protein in nature. When specific binding was defined by 0.1 microM nisoxetine, the binding was saturable and fitted a single-site binding model with a binding affinity of approximately 1 nM. This binding fraction was abolished by lesioning of the noradrenaline neurons with the noradrenaline neurotoxin N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4). In contrast, when 10 microM nisoxetine was used to define the specific binding, the binding was not saturable over the nanomolar range, but the binding fitted a two-site binding model with KD values of 0.5 and greater than 100 nM for the high- and low-affinity components, respectively. The high-affinity site was abolished after DSP4 lesioning, whereas the low-affinity site remained. The binding capacity (Bmax) for binding defined by 0.1 microM nisoxetine varied between brain regions, with very low density in the striatum (Bmax not possible to determine), 60-90 fmol/mg of protein in cortical areas and cerebellum, and 120 fmol/mg of protein in the hypothalamus. The binding capacities of these high-affinity sites correlated significantly with the regional distribution of [3H]noradrenaline uptake but not with 5-[3H]hydroxytryptamine uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug inhibition indicates a single-site model of the 5-HT uptake site/antidepressant binding site in rat and human brain.

Drug inhibition against [3H]paroxetine binding to rat cortex and human putamen was investigated in saturation experiments. The addition of 5-HT, imipramine, citalopram and clomipramine all produced changes in apparent binding affinity (Kd) without changes in the number of binding sites (Bmax). These data suggest that there is no heterogeneity of specific [3H]paroxetine binding, supporting a single site model of the 5-HT uptake site and antidepressant binding site.

Unaltered 5-HT- and desipramine-sensitive [3H]imipramine binding and [3H]5-HT uptake in rat brain after chronic imipramine and norzimeldine treatment.

Several reports have shown heterogeneity of [3H]imipramine binding to brain membranes. Recently, a high affinity and 5-HT sensitive [3H]imipramine binding site of protein nature, that was suggested to be identical to the substrate recognition site for 5-HT uptake, was demonstrated. Since most studies on the regulation of the [3H]imipramine binding sites by antidepressants have used desipramine displaceable binding, which is heterogenous in nature and contains binding not related to 5-HT uptake sites, the present report studies the possible effects of chronic (3 weeks) administration of imipramine or norzimeldine (10 mg/kg intraperitoneally twice daily) on 5-HT sensitive [3H]imipramine binding sites. For comparison, desipramine sensitive binding was also studied, as well as the physiological correlate 5-HT uptake. There were no changes in either [3H]imipramine binding or 5-HT uptake after the antidepressant treatment.

5-Hydroxytryptamine-sensitive [3H]imipramine binding of protein nature in the human brain. II. Effect of normal aging and dementia disorders.

Recently, a high-affinity [3H]imipramine binding site of protein nature that appeared related to the 5-hydroxytryptamine (5-HT, serotonin) uptake mechanism was demonstrated in the rat brain. In a preceding paper a similar [3H]imipramine binding site of protein nature and displaceable by 5-HT was demonstrated in the human brain. Most previous [3H]imipramine binding studies of the human brain have used desipramine-sensitive binding, which appears to contain a significant amount of additional binding not related to 5-HT neurons. Therefore this study of the human brain in the normal aging, in Alzheimer's disease/senile dementia of Alzheimer type (AD/SDAT) and in multiinfarction dementia (MID) presents data on 5-HT-sensitive [3H]imipramine binding. The influence of normal aging (17-100 years) was studied in the frontal and cingulate cortices, in the putamen, caudate nucleus, amygdala and in the hippocampus. An age-related change in 5-HT-sensitive [3H]imipramine binding was only noted in the cingulate cortex with a 50% loss in Bmax over the adult age range. In contrast, desipramine-sensitive [3H]imipramine binding studied in the frontal cortex and in the putamen showed marked increases in Bmax with age which correlated with increases in Kd. It is suggested that these increases are related to an increased binding to lipophilic membrane components not related to 5-HT neurons. The 5-HT-sensitive [3H]imipramine binding (Bmax) was reduced to 60% of control in the cingulate cortex and to 50% in the putamen in AD/SDAT. In MID there was a 50% loss of [3H]imipramine binding sites (Bmax) in the putamen, but a 30% loss in the cingulate cortex did not reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Hydroxytryptamine-sensitive [3H]imipramine binding of protein nature in the human brain. I. Characteristics.

[3H]Imipramine binding sites were characterized in the human brain by investigating the sensitivity to protease treatment, dependency on NaCl and the effects of drug inhibition. The binding was found to consist of a protease sensitive and a protease resistant fraction. These two fractions could be discriminated by 5-hydroxytryptamine (5-HT) but not desipramine. The [3H]imipramine binding discriminated by 5-HT was found to be sodium dependent. The 5-HT-sensitive [3H]imipramine binding displayed a regional variability with Bmax values ranging from 50 to 100 fmol/mg protein in neocortical areas to 400-500 fmol/mg protein in the substantia nigra and hypothalamus. The Kd values for 5-HT-sensitive [3H]imipramine binding were 1-2 nM throughout the brain. Additional [3H]imipramine binding insensitive to 5-HT, but displaceable by desipramine showed little regional variation, with the binding capacity in the hypothalamus approximating that found in cortical areas. This binding fraction was of low affinity, was not dependent on the presence of NaCl and was insensitive to protease treatment. Drug inhibition studies revealed that the addition of low concentrations of 5-HT or norzimeldine to 5-HT-sensitive [3H]imipramine binding sites produced changes in affinity, consistent with a competitive interaction. It is suggested that the 5-HT-sensitive [3H]imipramine binding may represent the substrate recognition site for 5-HT uptake in the human brain.

The regional distribution of dopamine and serotonin uptake and transmitter concentrations in the human brain.

The regional distribution of the dopamine and serotonin uptake sites in human brain have been assessed and compared with the distribution of the transmitters and their metabolites measured in the same brains and also with a limited regional distribution of the uptake sites in rat and sheep brain. The affinity of the uptake sites for both transmitters was determined and found to be c. 0.2 ? M in all 3 species. Most dopamine uptake in all species was in caudate and putamen samples. Many regions of the human brain showed no dopamine uptake and little dopamine uptake was seen in sheep cortex or nigral preparations. Dopamine and metabolite concentrations were highest in the caudate, putamen and substantia nigra. Most serotonin uptake was seen in the hypothalamus in all 3 species; less was observed in the striatal regions; the cortical and nigral preparations of sheep brain showed little serotonin uptake though cortical preparations of rat brain had high levels of uptake. In the human brain, other regions did not show serotonin uptake. Highest concentrations of serotonin were found in the substantia nigra and medulla, intermediate concentrations in the putamen, globus pallidus, hypothalamus, olfactory tubercle and thalamus; very low concentrations of serotonin were found in other regions. The use of the human uptake site for pharmacological studies and as a marker for monoaminergic afferents in human health and disease is discussed.

Single-site model of the neuronal 5-hydroxytryptamine uptake and imipramine-binding site.

Recently, a high affinity [3H]imipramine-binding site of protein nature that appeared to be related to the 5-hydroxytryptamine (5-HT, serotonin) uptake mechanism was demonstrated. This binding site was only part of desipramine-displaceable [3H]imipramine binding, which contained a significant amount of additional binding not related to 5-HT uptake. The present study further investigates the [3H]imipramine-binding site of protein nature in the rat brain. Displacement by 5-HT and 6-methoxytetrahydro-beta-carboline (6-MeO-TH beta C) revealed monophasic displacement patterns with 60% displaceable binding. This binding fraction was abolished by protease treatment of the brain tissue prior to binding assay. Saturation studies of [3H]imipramine binding (1-30 nM) in rat cortex showed that the binding displaced by 30 microM 5-HT [Bmax 322 +/- 16 fmol/mg of protein, Kd 4.17 +/- 1.07 nM (means +/- SE)] was not different from the binding displaced by 1.0 microM norzimeldine (Bmax 349 +/- 15 fmol/mg of protein, Kd 4.47 +/- 1.07 nM) or 30 microM 6-MeO-TH beta C (Bmax 439 +/- 28 fmol/mg of protein, Kd 5.49 +/- 1.09 nM). When 100 microM desipramine was used in saturation studies, the binding was different from that displaced by 5-HT with Bmax 608 +/- 42 fmol/mg of protein and Kd 6.68 +/- 1.09 nM. Both displacement and saturation studies in which two displacing agents were combined indicated that most of the binding competed by 5-HT (30 microM) and norzimeldine (1.0 microM) is identical. Similarly, the binding displaced by 5-HT or norzimeldine is subsumed within 6-MeO-TH beta C (30 microM)-displaceable binding. Lesion studies with parachloroamphetamine, a selective toxin for 5-HT terminals, which resulted in a 83% reduction of [3H] 5-HT uptake ( [3H]noradrenaline uptake unaffected), abolished cortical [3H]imipramine binding displaced by 30 microM 5-HT or 1.0 microM norzimeldine. (greater than 80% reduction). However, with 100 microM desipramine as displacer, 40% of the binding remained in lesioned animals. The [3H]imipramine binding displaced by 30 microM 5-HT or 1.0 microM norzimeldine was sodium dependent, and an increase in NaCl concentration from 0 to 120 mM resulted in a 10-fold increase in affinity without effect on Bmax, whereas no change in binding was observed with increasing concentrations of LiCl.(ABSTRACT TRUNCATED AT 400 WORDS)