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Biomedical subjects

R D Johnson

Publications and source records attributed to R D Johnson.

At least 19 recordsLinked to original sources
PubMed2006

The impact of spinal cord injury on sexual function: concerns of the general population.

STUDY DESIGN: Secure, web-based survey. OBJECTIVES: Obtain information from the spinal cord injured (SCI) population regarding sexual dysfunctions, with the aim of developing new basic science and clinical research and eventual therapies targeting these issues. SETTING: Worldwide web. METHODS: Individuals 18 years or older living with SCI. Participants obtained a pass-code to enter a secure website and answered survey questions. A total of 286 subjects completed the survey. RESULTS: The majority of participants stated that their SCI altered their sexual sense of self and that improving their sexual function would improve their quality of life (QoL). The primary reason for pursuing sexual activity was for intimacy need, not fertility. Bladder and bowel concerns during sexual activity were not strong enough to deter the majority of the population from engaging in sexual activity. However, in the subset of individuals concerned about bladder and/or bowel incontinence during sexual activity, this was a highly significant issue. In addition, the occurrence of autonomic dysreflexia (AD) during typical bladder or bowel care was a significant variable predicting the occurrence and distress of AD during sexual activity. CONCLUSION: Sexual function and its resultant impact on QoL is a major issue to an overwhelming majority of people living with SCI. This certainly constitutes the need for expanding research in multiple aspects to develop future therapeutic interventions for sexual health and SCI.

Adolescent↗
PubMed2006

Long-term effects of spinal cord injury on sexual function in men: implications for neuroplasticity.

STUDY DESIGN: Secure, web-based survey. OBJECTIVES: Elicit specific information about sexual function from men with spinal cord injuries (SCI). SETTING: World-wide web. METHODS: Individuals 18 years or older living with SCI obtained a pass-code to enter a secure website and then answered survey questions. RESULTS: The presence of genital sensation was positively correlated with the ability to feel a build up of sexual tension in the body during sexual stimulation and in the feeling that mental arousal translates to the genitals as physical sensation. There was an inverse relationship between developing new areas of arousal above the level of lesion and not having sensation or movement below the lesion. A positive relationship existed between the occurrence of spasticity during sexual activity and erectile ability. Roughly 60% of the subjects had tried some type of erection enhancing method. Only 48% had successfully achieved ejaculation postinjury and the most commonly used methods were hand stimulation, sexual intercourse, and vibrostimulation. The most commonly cited reasons for trying to ejaculate were for pleasure and for sexual intimacy. Less than half reported having experienced orgasm postinjury and this was influenced by the length of time postinjury and sacral sparing. CONCLUSION: SCI not only impairs male erectile function and ejaculatory ability, but also alters sexual arousal in a manner suggestive of neuroplasticity. More research needs to be pursued in a manner encompassing all aspects of sexual function.

Adaptation, Psychological↗
PubMed2006

Spinal cord injury influences psychogenic as well as physical components of female sexual ability.

STUDY DESIGN: Secure, web-based survey. OBJECTIVES: Elicit specific information about sexual function from women with spinal cord injuries (SCI). SETTING: World-wide web. METHODS: Individuals 18 years or older living with SCI obtained a pass code to enter a secure website and then answered survey questions. RESULTS: Bladder and/or bowel incontinence during sexual activity and/or sexual intercourse were significant concerns and prevented some women from seeking sexual activity. Autonomic dysreflexia (AD) during sexual activity was interpreted negatively by many and was found to interfere with sexual activity. Most subjects reported difficulty becoming psychologically aroused as well as physically aroused, which were both correlated with feeling that their SCI had altered their sexual sense of self. An inverse relationship existed between developing new areas of arousal above the level of lesion and not having sensation or movement below the lesion. The most commonly reported sexual stimulation leading to the best arousal involved stimulation of the head/neck and torso areas. The majority of subjects reported having experienced intercourse postinjury. Most participants reported difficulty with positioning during foreplay and intercourse, vaginal lubrication, and spasticity during intercourse. Almost half reported experiencing orgasm postinjury and this was positively associated with the presence of genital sensation. CONCLUSION: SCI significantly impairs psychological and physical aspects of female sexual arousal. In addition, bladder and bowel incontinence as well as AD negatively impact sexual activity and intercourse.

Adolescent↗
PubMed2006

Expression of TWIK-related acid sensitive K+ channels in capsaicin sensitive and insensitive cells of rat dorsal root ganglia.

Previous reports have demonstrated that small- to medium-diameter dorsal root ganglia (DRG) cells in rats can be subgrouped into individual cell types by patterns of voltage-activated currents. These cell types have consistent responses to algesic compounds and maintain characteristic histochemical phenotypes. Using immunocytochemical methods, we have now examined expression of TWIK (tandem of P domains in a weak inwardly rectifying K+ channel)-related acid sensitive K+ (TASK) channels, TASK-1, TASK-2 and TASK-3, in nine electrophysiologically identified small- to medium-diameter DRG cell types. The immunoreactivity in DRG cells was diverse, with all nine cell types expressing one to all three TASK channels. Some cells expressed TASK-1 (types 1, 4, 6 and 9), some TASK-2 (types 2, 4, 5, 6, 7 and 9), and some TASK-3 (types 1, 2, 3, 4, 5, 6 and 8). The co-expression of TASK-1 and TASK-3 in cell types 1, 4 and 6 suggests that these sensory afferents might contain functional heterodimeric channels. In peripheral sensory afferents, TASK channels have been implicated in the pain sensory transduction pathway, and can be modulated by anesthetics and neuroprotective agents. This study seeks to identify TASK channel populations in electrophysiologically characterized populations of putative nociceptive afferents.

Acetylcholine↗
PubMed2006

Proton sensitivity Ca2+ permeability and molecular basis of acid-sensing ion channels expressed in glabrous and hairy skin afferents.

We contrasted the physiology and peripheral targets of subclassified nociceptive and nonnociceptive afferents that express acid-sensing ion channel (ASIC)-like currents. The threshold for current activation was similar in eight distinct cell subclasses regardless of functional modality (pH 6.8). When potency was determined from concentration-response curves, nonnociceptors exhibited currents with significantly greater potency than that of all but one class of nociceptors (pH50 = 6.54 and 6.75 vs. 6.20-6.34). In nonnociceptive cells, acid transduction was also confined to a very narrow range (0.1-0.3 vs. 0.8-1.4 pH units for nociceptors). Simultaneous whole cell recording and ratiometric imaging of three peptidergic nociceptive classes were consistent with the expression of Ca2+ -permeable ASICs. Sensitivity to psalmotoxin and flurbiprofen indicated the presence of Ca2+ -permeable ASIC1a. Immunocytochemistry on these subclassified populations revealed a differential distribution of five ASIC proteins consistent with Ca2+ permeability and differential kinetics of proton-gated currents (type 5: ASIC1a, 1b, 2a, 2b, 3; type 8a: ASIC1a, 1b, 3; type 8b: ASIC1a, 1b, 2a, 2b, 3). Using DiI tracing, we found that nociceptive classes had discrete peripheral targets. ASIC-expressing types 8a and 9 projected to hairy skin, but only types 8a and 13 projected to glabrous skin. Non-ASIC-expressing types 2 and 4 were present only in hairy skin. We conclude that ASIC-expressing nociceptors differ from ASIC-expressing nonnociceptors mainly by range of proton reactivity. ASIC- as well as non-ASIC-expressing nociceptors have highly distinct cutaneous targets, and only one class was consistent with the existence of a generic C polymodal nociceptor (type 8a).

Acid Sensing Ion Channels↗
PubMed2005

Simultaneous analysis of thebaine, 6-MAM and six abused opiates in postmortem fluids and tissues using Zymark automated solid-phase extraction and gas chromatography-mass spectrometry.

Opiates are some of the most widely prescribed drugs in America and are often abused. Demonstrating the presence or absence of opiate compounds in postmortem fluids and/or tissues derived from fatal civil aviation accidents can have serious legal consequences and may help determine the cause of impairment and/or death. However, the consumption of poppy seed products can result in a positive opiate drug test. We have developed a simple method for the simultaneous determination of eight opiate compounds from one extraction. These compounds are hydrocodone, dihydrocodeine, codeine, oxycodone, hydromorphone, 6-monoacetylmorphine, morphine, and thebaine. The inclusion of thebaine is notable as it is an indicator of poppy seed consumption and may help explain morphine/codeine positives in cases where no opiate use was indicated. This method incorporates a Zymark RapidTracetrade mark automated solid-phase extraction system, gas chromatography/mass spectrometry, and trimethyl silane (TMS) and oxime-TMS derivatives. The limits of detection ranged from 0.78 to 12.5 ng/mL. The linear dynamic range for most analytes was 6.25-1600 ng/mL. The extraction efficiencies ranged from 70 to 103%. We applied this method to eight separate aviation fatalities where opiate compounds had previously been detected.

Autoanalysis↗
PubMed2005

Diverse immunocytochemical expression of opioid receptors in electrophysiologically defined cells of rat dorsal root ganglia.

The development of opiate analgesics that do not produce adverse side effects is hampered by the difficulty in developing drugs that are tissue/sensory cell-specific. Previously, our laboratory has demonstrated that small- and medium-diameter dorsal root ganglia (DRG) cells can be subclassified into at least nine distinct cell types based upon their patterns of voltage activated currents [Petruska, J.C., Napaporn, J., Johnson, R.D., Gu, J.G., Cooper, B.Y., 2000. Subclassified acutely dissociated cells of rat DRG: histochemistry and patterns of capsaicin-, proton-, and ATP-activated currents. J. Neurophysiol. 84 (5), 2365-2379; Petruska, J.C., Napaporn, J., Johnson, R.D., Cooper, B.Y., 2002. Chemical responsiveness and histochemical phenotype of electrophysiologically classified cells of the adult rat dorsal root ganglion. Neuroscience 115 (1), 15-30.] Based on their responses to algesic compounds and histochemical phenotype, eight of the nine subtypes are likely nociceptors. In the present study, we examined the immunoreactivity (IR) of delta-, kappa- and mu-opioid receptors (DOR, KOR and MOR, respectively), in 164 electrophysiologically subclassified DRG neurons. The expression of opioid receptors in the DRG cell types was diverse. Type 1 (25-30 microm cell diameter) and type 9 (35-45 microm) expressed MOR-IR, but were negative for DOR-IR and KOR-IR. Type 2 (25-30 microm) co-expressed DOR-IR and MOR-IR, but did not express KOR-IR. Type 3 (15-20 microm), the non-nociceptive cell type, was not immunoreactive. Type 4 (35-45 microm), type 6 (35-45 microm), and type 7 (15-20 microm) expressed all three opioid receptors. Type 5 (35-45 microm) and type 8 (35-45 microm), co-expressed KOR-IR and MOR-IR, but did not express DOR-IR. The co-expression of opioid receptors in some of the cell types suggests that these sensory afferents might contain heteromeric opioid receptors. Additionally, the diverse expression patterns of opioid receptors between cell types and the consistency of these patterns maintained within each cell type provides further evidence of distinct functional properties of DRG nociceptors.

Afferent Pathways↗
PubMed2005

Internal carotid blood flow and cerebral hemispheric perfusion in patients with subarachnoid haemorrhage: a study of the quantix/NDtrade mark system and CT perfusion technology.

OBJECTIVE: To assess whether carotid blood flow measurements predict abnormalities in cerebral hemispheric perfusion. DESIGN: The Quantix/NDTM system was used to measure carotid artery blood flow in nine patients with subarachnoid haemorrhage who underwent CT perfusion scanning. RESULTS: No significant correlation was found between internal carotid artery blood flow and ipsilateral cerebral hemispheric perfusion (013, p>0.05) but there was a statistically significant correlation between total internal carotid and global cerebral perfusion (0.63, p<0.05). CONCLUSIONS: This is the first report comparing the Quantix/NDTM system with CT perfusion. Our data do not show a statistically significant correlation between extracranial blood flow and cerebral hemispheric perfusion. This is in contrast to two previous studies where Quantix/NDTM measurements were compared with measurements of cerebral perfusion using the Xenon clearance technique.

Carotid Artery, Internal↗
PubMed2004

Nicotinic AChR in subclassified capsaicin-sensitive and -insensitive nociceptors of the rat DRG.

Nociceptive cells of the dorsal root ganglion (DRG) were subclassified, in vitro, according to patterns of voltage-activated currents. The distribution and form of nicotinic ACh receptors (nAChRs) were determined. nAChRs were present on both capsaicin-sensitive and -insensitive nociceptors but were not universally present in unmyelinated nociceptors. In contrast, all A delta nociceptors (types 4, 6, and 9) expressed slowly decaying nAChR. Three major forms of nicotinic currents were identified. Specific agonists and antagonists were used to demonstrate the presence of alpha7 in two classes of capsaicin-sensitive, unmyelinated nociceptors (types 2 and 8). In type 2 cells, alpha7-mediated currents were found in isolation. Whereas alpha7 was co-expressed with other nAChR in type 8 cells. These were the only classes in which alpha7 was identified. Other nociceptive classes expressed slowly decaying currents with beta4 pharmacology. Based on concentration response curves formed by nicotinic agonists [ACh, nicotine, dimethyl phenyl piperazinium (DMPP), cytisine] evidence emerged of two distinct nAChR differentially expressed in type 4 (alpha3beta4) and types 5 and 8 (alpha3beta4 alpha5). Although identification could not be made with absolute certainty, patterns of potency (type 4: DMPP > cytisine > nicotine = ACh; type 5 and type 8: DMPP = cytisine > nicotine = ACh) and efficacy provided strong support for the presence of two distinct channels based on an alpha3beta4 platform. Studies conducted on one nonnociceptive class (type 3) failed to reveal any nAChR. After multiple injections of Di-I (1,1'-dilinoleyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) into the hairy skin of the hindlimb, we identified cell types 2, 4, 6, 8, and 9 as skin nociceptors that expressed nicotinic receptors. We conclude that at least three nicotinic AChR are diversely distributed into discrete subclasses of nociceptors that innervate hairy skin.

Animals↗
PubMed2004

Determination of cocaine, its metabolites, pyrolysis products, and ethanol adducts in postmortem fluids and tissues using Zymark automated solid-phase extraction and gas chromatography-mass spectrometry.

Demonstrating the presence or absence of cocaine (COC) and COC-related molecules in postmortem fluids and/or tissues can have serious legal consequences and may help determine the cause of impairment and/or death. We have developed a simple method for the simultaneous determination of COC and the COC metabolites benzoylecgonine (BE), norbenzoylecgonine (NBE), ecgonine methyl ester (EME), ecgonine (E), and norcocaine (NCOC), as well as anhydroecgonine methyl ester (AEME) (a unique byproduct of COC smoking), cocaethylene (a molecule formed by the concurrent use of COC and ethanol) and their related metabolites, anhydroecgonine (AE), norcocaethylene (NCE), and ecgonine ethyl ester (EEE). This method incorporates a Zymark RapidTrace automated solid-phase extraction (SPE) system, gas chromatography/mass spectrometry (GC/MS) and 2,2,3,3,3-pentafluoro-1-propanol (PFP)/pentafluoropropionic anhydride (PFPA) derivatives. The lower limits of detection ranged from 0.78 to 12.5 ng/mL and the linear dynamic range for most analytes was 0.78-3200 ng/mL. The extraction efficiencies were from 26 to 84% with the exception of anhydroecgonine and ecgonine, which were from 1 to 4%. We applied this method to five aviation fatalities. This method has proven to be simple, robust and accurate for the simultaneous determination of COC and 11 COC metabolites in postmortem fluids and tissues.

Automation↗
PubMed2004

Accurate assignment of ethanol origin in postmortem urine: liquid chromatographic-mass spectrometric determination of serotonin metabolites.

Toxicological examination of fatal aviation accident victims routinely includes analysis of ethanol levels. However, distinguishing between antemortem ingestion and postmortem microbial formation complicates all positive ethanol results. Development of a single analytical approach to determine concentrations of 5-hydroxytryptophol (5-HTOL) and 5-hydroxyindole-3-acetic acid (5-HIAA), two well-known metabolites of serotonin, has provided a convenient, rapid and reliable solution to this problem. Antemortem ethanol leads to an elevation in the 5-HTOL/5-HIAA ratio for 11-19 h after acute ingestion. The liquid-liquid extracts of postmortem urine samples were subjected to liquid chromatography-mass spectrometry (LC-MS) for the simultaneous quantitation of these two analytes, yielding detection limits of 0.1 ng/ml for each. Examination of the 5-HTOL/5-HIAA ratio was undertaken for 44 urine samples known to be antemortem ethanol-positive or antemortem ethanol-negative. Recent ethanol ingestion was conveniently and accurately separated using a 5-HTOL/5-HIAA ratio of 15 pmol/nmol, a value previously suggested using human volunteers. All 21 ethanol-negative postmortem samples were below this cutoff, while all 23 ethanol-positive postmortem samples were above this cutoff. Thus, we recommend the employment of this cutoff value, established using this straightforward LC-MS procedure, to confirm or deny recent antemortem ethanol ingestion in postmortem urine samples.

Chromatography, High Pressure Liquid↗
PubMed2004

Characterization and function of TWIK-related acid sensing K+ channels in a rat nociceptive cell.

We examined the properties of a proton sensitive current in acutely dissociated, capsaicin insensitive nociceptive neurons from rat dorsal root ganglion (DRG). The current had features consistent with K(+) leak currents of the KCNK family (TASK-1, TASK-3; TWIK-related acid sensing K(+)). Acidity and alkalinity induced inward and outward shifts in the holding current accompanied by increased and decreased whole cell resistance consistent with a K(+) current. We used alkaline solutions to open the channel and examine its properties. Alkaline evoked currents (AECs; pH 10.0-10.75), reversed near the K(+) equilibrium potential (-74 mV), and were suppressed 85% in 0 mM K(+). AECs were insensitive to Cs(+) (1 mM) and anandamide (1 microM), but blocked by Ba(++) (1 mM), quinidine (100 microM) or Ruthenium Red (10 microM). This pharmacology was identical to that of rat TASK-3 and inconsistent with that of TASK-1 or TASK-2. The TASK-like AEC was not modulated by PKA (forskolin, kappa opioid agonists U69593 and GR8696, somatostatin) but was inhibited by PKC activator phorbol-12-myristate-13 acetate (PMA). When acidic solutions were used, we were able to isolate a Ba(++) and Ruthenium Red insensitive current that was inhibited by Zn(++). This Zn(++) sensitive component of the proton sensitive current was consistent with TASK-1. In current clamp studies, acidic pH produced sensitive changes in resting membrane potential but did not influence excitability (pH 7.2-6.8). In contrast, Zn(++) produced substantial changes in excitability at physiological pH. Alkaline solutions produced hyperpolarization followed by proportional burst discharges (pH 10.75-11.5) and increased excitability (at pH 7.4). In conclusion, multiple TASK currents were present in a DRG nociceptor and differentially contributed to distinct discharge mechanisms.

Animals↗
PubMed2002

Chemical responsiveness and histochemical phenotype of electrophysiologically classified cells of the adult rat dorsal root ganglion.

Whole cell patch recordings were obtained from medium diameter (35-45 microm) dorsal root ganglion neurons. Using electrophysiological parameters, we were able to subclassify acutely dissociated dorsal root ganglion cells into three uniform (types 5, 6 and 9) and one mixed class (type 8) of neurons. All subtypes (types 5, 6, 8 and 9) had broad action potentials (7.0+/-0.2, 5.2+/-0.4, 7.3+/-0.5 and 6.0+/-0.4 ms) and exceptionally long afterhyperpolarizations (112+/-9, 178+/-19, 124+/-31 and 204+/-33 ms). Long afterhyperpolarizations have been linked to mechanically insensitive (silent) nociceptors by other laboratories [Djouhri et al., J. Physiol. 513 (1998) 857-872]. Chemosensitivity varied among cell classes. Cell types 5, 8 and 9 were capsaicin sensitive (45+/-13, 87+/-30 and 28+/-13 pA/pF; 5 microM) groups, while the type 6 cell was capsaicin insensitive. All cell types expressed ASIC-like (acid sensing ion channel) amiloride sensitive, proton-activated currents with a threshold of pH 6.8 and a peak near pH 5.0. All medium sized cells were sensitive to ATP (50 microM) and exhibited the 'mixed' form of ATP-gated current [Burgard et al., J. Neurophysiol. 82 (1999) 1590-1598; Grubb and Evans, Eur. J. Neurosci. 11 (1999) 149-154]. Immunohistochemistry performed on individual cells indicated the expression of both P2X(1) and P2X(3) subunits. Electrophysiologically defined classes were histochemically uniform. All types were examined for the presence of substance P (SP), calcitonin gene related peptide (CGRP) and binding of isolectin B4 (IB4). All subtypes expressed CGRP immunoreactivity. Types 5 and 8 co-expressed SP and CGRP immunoreactivity and also bound IB4. Subtypes 6 and 9 were positive for neurofilament m. It is likely that these cells represent major classes of myelinated and unmyelinated peptide expressing nociceptors.

Animals↗
PubMed2001

Elimination of ergovaline from a grass-Neotyphodium endophyte symbiosis by genetic modification of the endophyte.

The fungal endophytes Neotyphodium lolii and Neotyphodium sp. Lp1 from perennial ryegrass (Lolium perenne), and related endophytes in other grasses, produce the ergopeptine toxin ergovaline, among other alkaloids, while also increasing plant fitness and resistance to biotic and abiotic stress. In the related fungus, Claviceps purpurea, the biosynthesis of ergopeptines requires the activities of two peptide synthetases, LPS1 and LPS2. A peptide synthetase gene hypothesized to be important for ergopeptine biosynthesis was identified in C. purpurea by its clustering with another ergot alkaloid biosynthetic gene, dmaW. Sequence analysis conducted independently of the research presented here indicates that this gene encodes LPS1 [Tudzynski, P., Holter, K., Correia, T., Arntz, C., Grammel, N. & Keller, U. (1999) Mol. Gen. Genet. 261, 133-141]. We have cloned a similar peptide synthetase gene from Neotyphodium lolii and inactivated it by gene knockout in Neotyphodium sp. Lp1. The resulting strain retained full compatibility with its perennial ryegrass host plant as assessed by immunoblotting of tillers and quantitative PCR. However, grass-endophyte associations containing the knockout strain did not produce detectable quantities of ergovaline as analyzed by HPLC with fluorescence detection. Disruption of this gene provides a means to manipulate the accumulation of ergovaline in endophyte-infected grasses for the purpose of determining the roles of ergovaline in endophyte-associated traits and, potentially, for ameliorating toxicoses in livestock.

Base Sequence↗
PubMed2001

Co-expression of P2X receptor subunits on rat nodose neurons that bind the isolectin GS-I-B4.

Triple fluorescent histochemistry was used to describe the types of overlap in visceral sensory neurons (nodose ganglion) for the labeling of the isolectin B4 from Griffonia simplicifolia type one (GS-I-B4) and their immunoreactivity (IR) for two of the ATP receptor subunits (P2X1/3 or P2X2/3). The vast majority of nodose neurons expressed GS-I-B4-binding and most of these displayed P2X receptor IR. Most of the P2X-IR was co-expressed on these individual nodose neurons (P2X1/P2X3 or P2X2/P2X3). A very small subpopulation of neurons that were GS-I-B4 negative but P2X positive displayed a very high relative intensity of P2X3-IR. The functional role that these expression patterns play in visceral sensory processing is currently unclear.

Animals↗
PubMed2001

Development of a fully integrated analysis system for ions based on ion-selective optodes and centrifugal microfluidics.

A fully integrated, miniaturized analysis system for ions based on a centrifugal microfluidics platform and ion-selective optode membranes is described. The microfluidic architecture is composed of channels, five solution reservoirs, a measuring chamber, and a waste reservoir manufactured onto a disk-shaped substrate of poly(methyl methacrylate). Ion-selective optode membranes, composed of plasticized poly(vinyl chloride) impregnated with an ionophore, a proton chromoionophore, and a lipophilic anionic additive, were cast, with a spin-on device, onto a support layer and then immobilized on the disk. Fluid propulsion is achieved by the centrifugal force that results from spinning the disk, while a system of valves is built onto the disk to control flow. These valves operate based on fluid properties and fluid/substrate interactions and are controlled by the angular frequency of rotation. With this system, we have been able to deliver calibrant solutions, washing buffers, or "test" solutions to the measuring chamber where the optode membrane is located. An analysis system based on a potassium-selective optode has been characterized. Results indicate that optodes immobilized on the platform demonstrate theoretical responses in an absorbance mode of measurement. Samples of unknown concentration can be quantified to within 3% error by fitting the response function for a given optode membrane using an acid (for measuring the signal for a fully protonated chromoionophore), a base (for fully deprotonated chromoionophore), and two standard solutions. Further, the ability to measure ion concentrations by employing one standard solution in conjunction with acid and base and with two standards alone were studied to delineate whether the current architecture could be simplified. Finally, the efficacy of incorporating washing steps into the calibration protocol was investigated.

Calibration↗
PubMed2001

Phase II study of pemetrexed disodium, a multitargeted antifolate, and cisplatin as first-line therapy in patients with advanced nonsmall cell lung carcinoma: a study of the National Cancer Institute of Canada Clinical Trials Group.

BACKGROUND: Pemetrexed disodium (Alimta [Eli Lilly and Company, Indianapolis, IN], LY231514, multitargeted antifolate) is a new multitargeted antifolate agent that inhibits multiple enzymes in the folate pathway. Phase II trials showed single-agent response rates of 16% and 23% in untreated patients with nonsmall cell lung carcinoma (NSCLC). This study was undertaken to determine the response to pemetrexed disodium given in combination with cisplatin. METHODS: Previously untreated patients were eligible if they had Stage IIIB or IV NSCLC, performance status 0, 1, or 2, adequate hematology and biochemistry and bidimensionally measurable lesions. Patients with brain metastases or neuropathy higher than Grade 2 were excluded. Pemetrexed disodium 500 mg/m(2) was given over 10 minutes, and cisplatin 75 mg/m(2) with hydration and mannitol diuresis was administered on Day 1 of each 21-day cycle. Dexamethasone 4 mg was taken orally once every 12 hours starting 24 hours before treatment and continuing for 6 doses after treatment. Four patients had detailed pemetrexed disodium pharmacokinetic analysis performed. RESULTS: Between May 1998 and June 1999, 31 patients were treated on the study. There were 20 males and 11 females; median age was 60 years (range, 35-75 years); there were 5 Stage IIIB, 26 Stage IV, 26 performance status 0 or 1, and 5 performance status 2. In 29 patients evaluable for response, there were 13 partial responses (PRs; overall response rate [ORR], 95%; confidence interval [CI]: 26-64%) of median duration 6.1 months (1.6-7.8 months). Three of four evaluable patients with performance status 2 achieved PR, and 11 of 24 evaluable Stage IV patients responded (ORR, 45.8% in Stage IV). Eighteen patients died. The median survival rate was 8.9 months (range, 1-15+ months). A total of 160 courses were delivered (median, 6 for both cisplatin and pemetrexed disodium). Grade 3 and 4 anemia was observed in 5 and 1 patients, respectively, and Grade 3 and 4 granulocytopenia in 7 and 4 patients, respectively. Grade 3 nausea and emesis occurred in only 2 patients, Grade 3/4 diarrhea in 3 patients, and 2 patients had Grade 3 motor neuropathy. Nine patients had Grade 2 infections, and there was one case of febrile neutropenia. Pharmacokinetic results showed C(max), clearance and V(ss) values to be similar to data from single-agent pemetrexed disodium given in the same dose. CONCLUSIONS: The combination of pemetrexed disodium and cisplatin is active against advanced NSCLC and is a well-tolerated convenient outpatient regimen. It deserves further study to compare it with other standard regimens for NSCLC.

Adult↗