Comparison of the novel subtype-selective GABAA receptor-positive allosteric modulator NS11394 [3'-[5-(1-hydroxy-1-methyl-ethyl)-benzoimidazol-1-yl]-biphenyl-2-carbonitrile] with diazepam, zolpidem, bretazenil, and gaboxadol in rat models of inflammatory and neuropathic pain.

Spinal administration of GABA(A) receptor modulators, such as the benzodiazepine drug diazepam, partially alleviates neuropathic hypersensitivity that manifests as spontaneous pain, allodynia, and hyperalgesia. However, benzodiazepines are hindered by sedative impairments and other side effect issues occurring mainly as a consequence of binding to GABA(A) receptors containing the alpha(1) subunit. Here, we report on the novel subtype-selective GABA(A) receptor-positive modulator NS11394 [3'-[5-(1-hydroxy-1-methyl-ethyl)-benzoimidazol-1-yl]-biphenyl-2-carbonitrile], which possesses a functional efficacy selectivity profile of alpha(5) > alpha(3) > alpha(2) > alpha(1) at GABA(A) alpha subunit-containing receptors. Oral administration of NS11394 (1-30 mg/kg) to rats attenuated spontaneous nociceptive behaviors in response to hindpaw injection of formalin and capsaicin, effects that were blocked by the benzodiazepine site antagonist flumazenil. Ongoing inflammatory nociception, observed as hindpaw weight-bearing deficits after Freund's adjuvant injection, was also completely reversed by NS11394. Likewise, hindpaw mechanical allodynia was fully reversed by NS11394 in two rat models of peripheral neuropathic pain. Importantly, NS11394-mediated antinociception occurred at doses 20 to 40-fold lower than those inducing minor sedative or ataxic impairments. In contrast, putative antinociception associated with administration of either diazepam, zolpidem, or gaboxadol only occurred at doses producing intolerable side effects, whereas bretazenil was completely inactive despite minor influences on motoric function. In electrophysiological studies, NS11394 selectively attenuated spinal nociceptive reflexes and C-fiber-mediated wind-up in vitro pointing to involvement of a spinal site of action. The robust therapeutic window seen with NS11394 in animals suggests that compounds with this in vitro selectivity profile could have potential benefit in clinical treatment of pain in humans.

NS11394 [3'-[5-(1-hydroxy-1-methyl-ethyl)-benzoimidazol-1-yl]-biphenyl-2-carbonitrile], a unique subtype-selective GABAA receptor positive allosteric modulator: in vitro actions, pharmacokinetic properties and in vivo anxiolytic efficacy.

The novel positive allosteric modulator NS11394 [3'-[5-(1-hydroxy-1-methyl-ethyl)-benzoimidazol-1-yl]-biphenyl-2-carbonitrile] possesses a functional selectivity profile at GABA(A) receptors of alpha(5) > alpha(3) > alpha(2) > alpha(1) based on oocyte electrophysiology with human GABA(A) receptors. Compared with other subtype-selective ligands, NS11394 is unique in having superior efficacy at GABA(A)-alpha(3) receptors while maintaining low efficacy at GABA(A)-alpha(1) receptors. NS11394 has an excellent pharmacokinetic profile, which correlates with pharmacodynamic endpoints (CNS receptor occupancy), yielding a high level of confidence in deriving in vivo conclusions anchored to an in vitro selectivity profile and allowing for translation to higher species. Specifically, we show that NS11394 is potent and highly effective in rodent anxiety models. The anxiolytic efficacy of NS11394 is most probably mediated through its high efficacy at GABA(A)-alpha(3) receptors, although a contributory role of GABA(A)-alpha(2) receptors cannot be excluded. Compared with benzodiazepines, NS11394 has a significantly reduced side effect profile in rat (sedation, ataxia, and ethanol interaction) and mouse (sedation), even at full CNS receptor occupancy. We attribute this benign side effect profile to very low efficacy of NS11394 at GABA(A)-alpha(1) receptors and an overall partial agonist profile across receptor subtypes. However, NS11394 impairs memory in both rats and mice, which is possibly attributable to its efficacy at GABA(A)-alpha(5) receptors, albeit activity at this receptor might be relevant to its antinociceptive effects (J Pharmacol Exp Ther 327:doi;10.1124/jpet.108.144, 2008). In conclusion, NS11394 has a unique subtype-selective GABA(A) receptor profile and represents an excellent pharmacological tool to further our understanding on the relative contributions of GABA(A) receptor subtypes in various therapeutic areas.

Antiepileptics and the treatment of neuropathic pain: evidence from animal models.

Neuropathic pain is characterised by both positive (hyperalgesia and allodynia) and negative (sensory deficits) symptoms and remains intractable to many commonly used analgesics. Antiepileptics are increasingly utilised in the treatment of neuropathic pain. This class of drugs works via three major mechanisms of action in order to dampen neuronal hyperexcitability within the central nervous system: potentiation of GABA transmission, reduction of glutamate-mediated excitatory transmission, and block of voltage-activated ion channels. The latter mechanism of action in particular, is exemplified by the success of the newer generation of antiepileptics such as lamotrigine and gabapentin in the clinical treatment of neuropathic pain symptoms. In the current review article, we will examine in detail, the antinociceptive effects of a diverse range of antiepileptics as tested in animal models of nerve injury. Where appropriate, we will compare these findings with their analgesic efficacy in the clinical treatment of neuropathic pain.

SNPs in cancer research and treatment.

Genetic variation in the human genome is an emerging resource for studying cancer, a complex set of diseases characterised by both environmental and genetic contributions. The number of common germ-line variants is great, on the order of 10-15 million per person, and represents a remarkable opportunity to investigate the aetiology, interindividual differences in treatment response and outcomes of specific cancers. The study of genetic variation can elucidate critical determinants in environmental exposure and cancer, which could have future implications for preventive and early intervention strategies. However, we are in the initial stages of characterising the tools (i.e., the single-nucleotide polymorphism, SNP) to rigorously analyse the genetic contributions to complex diseases, such as cancer. If the promise of the genomic era is to be realised, we must integrate this information into new strategies for implementation in both public health measures and, most importantly, provision of individual cancer-related care.

Characterization of the genomic structure of the human vitamin C transporter SVCT1 (SLC23A2).

Vitamin C (L-ascorbic acid), a critical cofactor for intracellular enzymatic reactions, functions as a scavenger of free oxygen radicals and is an essential micronutrient. Vitamin C is actively transported into cells by one of two closely related sodium-dependent transporters, SVCT1 or SVCT2. In this paper, we report the complete sequencing and gene structure of SLC23A2, the gene encoding SVCT1. The1797-bp cDNA sequence (open reading frame) of the SLC23A2 gene was derived from a compact genomic sequence of 7966 bp [translation initiation codon (ATG) to poly A tail], which is divided into 14 exons. Furthermore, repetitive or masked elements constituted 17.98% of the gene; there were 4 Alu sequences and 5 MIR (Mammalian Interspersed Repetitive element) sequences. A search for common variants in SLC23A2, using current bioinformatic tools and direct resequencing of control populations, failed to identify common single nucleotide polymorphisms. The start of transcription was mapped to a position -47 relative to the ATG; the immediate 5' sequence was determined and analyzed for possible consensus binding sites for known transcription factors. Our findings will serve as the foundation for investigation of the regulation and expression of the tissue-specific sodium-dependent vitamin C transporter, SLC23A2.

Polymorphisms in inflammatory cytokines and Fcgamma receptors in childhood chronic immune thrombocytopenic purpura: a pilot study.

Inflammatory cytokines and low-affinity Fcgamma receptor (FcgammaR) polymorphisms were investigated in 37 children with chronic immune thrombocytopenic purpura (cITP) and 218 controls. Genotype analysis included common variants in the regulatory regions of cytokines, TNF, LTA, IL1RN, IL1A, IL1B, IL4, IL6 and IL10, and structural variants of the low affinity FcgammaRs, FCGR2A, FCGR3A and FCGR3B. Associations were observed for TNF (P = 0.0032), LTA (P = 0.019), FCGR3A (P = 0.038) and FCGR3B (P = 0.0034). Two combinations of genotypes (TNF and FCGR3A; P = 0.0003, and LTA and FCGR3B; P = 0.011) were significantly associated with cITP. These results provide preliminary evidence that variant genotypes of FcgammaRs and cytokines contribute to cITP pathogenesis.

Glutamine dipeptides-supplemented parenteral nutrition reverses gut mucosal structure and interleukin-6 release of rat intestinal mononuclear cells after hemorrhagic shock.

Glutamine is an essential substrate for gut mucosal structure, but the role for gut immune function is not fully known. To determine the effect on gut cytokine release in relation to bacterial translocation and gut morphology, a nonlethal hemorrhagic shock (30 min, 30 mmHg) was performed in male Wistar rats followed by 4 days of different way of feeding. A conventional total parenteral nutrition (TPN) solution was compared with an isocaloric and isonitrogenous TPN solution supplemented with alanin-L-glutamine and glycyl-L-glutamine. An enteral chow-fed control group was included. Gut mononuclear cells and splenic macrophages were obtained and endotoxin-induced supernatant tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) bioactivity was measured. Histological specimen of the small bowel were taken and mesenteric lymph nodes (MLN) were separated. Enteral feeding following hemorrhagic shock was accompanied by a normal mucosal structure and no bacterial translocation could be detected. TPN was characterized by suppression of cytokine release in gut mononuclear cells and splenic macrophages compared with the enteral-fed control (p < .05). Decreased TNF and IL-6 release was associated with a significantly increased mucosal injury score (p < .05) and a high incidence of bacterial translocation to MLN (66%, p < .05 vs. control). Supplementation of glutamine-dipeptides did not prevent TPN-induced bacterial translocation to MLN (p < .05 vs. control) but significantly improved mucosal injury (p < .05 vs. TPN). Down-regulation of TNF release in TPN-fed rats could not be reversed by glutamine dipeptides while IL-6 release was significantly increased compared with TPN-fed animals (p < .05), and no difference to enteral-fed controls could be found. Enteral nutrition following hemorrhagic shock is superior to parenteral nutrition with regard to mucosal structure, cytokine release, and bacterial translocation. Supplementation of TPN with glutamine dipeptides could reverse TPN-induced suppression of IL-6 release and improved mucosal structure, which may be beneficial in various disease conditions in which TPN is an integrated part of patients management.

[Effect of postoperative endonasal mucous membrane care on nasal bacterial flora: prospective study of 2 irrigation methods with NaCl solution after paranasal sinus surgery]. / Der Einfluss der postoperativen endonasalen Schleimhautpflege auf die nasale Bakterienflora: Prospektive Untersuchung zweier Spülverfahren mit NaCl-Lösung nach Nasennebenhöhlenchirurgie.

BACKGROUND: Endonasal irrigation with saline solution is a widely used constituent of mucosal care after sinus surgery. This procedure could explain a repeatedly observed phenomenon: contamination of the endonasal mucosa by facultative skin pathogens from the palm during paranasal sinus irrigation. METHOD: For this reason the effect of nasal rinses with saline solution on the endonasal bacterial flora was investigated (use of so-called nasal douche [Siemens & Co., Bad Ems] compared to rinsing by hand). In 36 patients (23 m., 13 f., 36 +/- 19.5 years of age) with chronic sinusitis, a total of 288 swabs was collected before, during, and after surgery. The collected specimens were transferred to a Port-A-Cul transport medium and processed within four hours. RESULTS: Two hundred sixty-six cultures of 325 bacterial strains were aerobic (82%), while 59 were anaerobic (18%). Staphylococcus aureus (33%) and representatives of the Enterobacteriaceae family (31%) were the most common enriched germs. The number of times that enterobacteriaceae could be isolated was significantly (p < 0.05) lower (13%) when a nasal douche was used than when irrigation was done using the palm (38%). An irrigation technique-related effect was found on neither the spectrum of the pathagonic organisms nor the wound healing process. CONCLUSION: The frequent isolation of enterobacteria in nasal swabs of individuals rinsing by hand constitutes the difference between irrigation by nasal douche and by hand in the postoperative care of the endonasal mucosa. These pathogens can sustain the paranasal sinus system.

Gastroesophageal reflux disease. Acute and maintenance treatments with cimetidine.

The comparative efficacy of a 12-week acute treatment with 800 and 1600 mg cimetidine daily and the effectiveness of a 400-mg single-dose maintenance treatment versus placebo lasting 6 months were studied in a double-blind fashion in 30 and 24 patients, respectively, with gastroesophageal reflux (GER) disease. Cimetidine in a dose of 800 or 1600 mg daily resulted in a significant symptomatic improvement and a decrease in the extent of endoscopic esophagitis. An improvement in the gastroesophageal sphincter function during treatment was suggested by a significant decrease in the frequency of reflux, as evaluated by isotope scintigraphy. No significant differences were found between the two doses of cimetidine. The overall initial improvement tended to be maintained during maintenance treatment, but no significant differences were found between cimetidine and placebo. The present study thus supports the use of 800 mg of cimetidine daily for short-term treatment of GER disease but provides no support for maintenance treatment with a low dose. The study further suggests that cimetidine treatment, by reducing the tendency to GER, may induce long-lasting remission of the disease.

Palliative intubation in malignant stricture of the oesophagus and cardia.

One-hundred patients treated with oesophageal intubation for stricture-forming inoperable oesophago-gastric malignancies during the years 1972 to 1983 were analyzed. Fifteen tubes were endoscopically positioned, the rest by thoracotomy or laparotomy. Seven patients died from causes related to the intubation, the causes of death being perforation (2), mediastinitis (3) or aortic erosion (2). Mean survival-time was three months (range one day to 14 months). Nineteen of the most deteriorated patients died within two weeks. Eighty-seven percent of the patients experienced relief of dysphagia. Thus the intended palliation was satisfactory and the results therefore support oesophageal intubation as an alternative to be considered in the treatment of malignancies of the oesophagus and cardia. However, deteriorated patients with extremely short life expectancy might not benefit from the procedure.

Scintigraphy, pH measurement, and radiography in the evaluation of gastroesophageal reflux.

Scintigraphy as a diagnostic tool has been explored in 69 patients with gastroesophageal reflux (GER) symptoms and endoscopic esophagitis. In all subjects the presence of reflux was also evaluated by radiography and intraesophageal pH measurements (standard acid reflux test). The overall sensitivity of scintigraphy (85.5%) was significantly higher than those of radiography (27.5%) and pH measurements (69.5%). Scintigraphy was performed with normal saline and with acidified orange juice as the transport medium for the isotope 99mTc. The yield of positive scintigrams was higher (22.3 to 61.1%, depending on the grade of endoscopic esophagitis) with the latter variant. Moreover, demonstration of spontaneous reflux was greatly facilitated by the acid scintigraphy. This was particularly obvious in the grade I esophagitis, in which the frequency of spontaneous reflux with the saline method was 3.4% and with the acid medium, 34.3%. Reflux (induced or spontaneous) was seen in 2 of 22 normal control subjects with the saline method and in 1 subject only with the acid method. On the basis of these findings, it is concluded that scintigraphy, especially the acid variant of the technique, is a valuable diagnostic procedure in GER disease.

Treatment with secretin and a cholecystokinin-like peptide in patients with pancreatic cancer. A pilot study.

Secretin and cholecystokinin (CCK) have trophic effects on the pancreas and may therefore have a place in the treatment of pancreatic cancer. The present study was performed to examine whether these hormones may cause harm in patients with pancreatic cancer receiving cytostatics. The cytostatics were 5-fluorouracil, adriamycin, and mitomycin C(FAM). Secretin plus Thr28Nle31CCK25-33, in doses stimulating pancreatic secretion to about 60% of maximal, were given as a continuous 6-day intravenous infusion just before (four patients) or immediately after (five patients) starting treatment with FAM. Five patients received FAM only. When considering symptoms, laboratory findings, abdominal CT scans, and survival, no evidence was found that secretin and CCK may cause serious or unpleasant side effects in patients with pancreatic cancer receiving cytostatics.

Prophylactic regimens in colorectal surgery. Comparison between metronidazole used alone or in combination with either ampicillin or doxycycline.

Sixteen hospitals are participating in this study, that started in October 1982 and will be concluded when 456 patients have been admitted. The study includes patients eligible for elective colorectal surgery. Inclusion criteria, surgical techniques, definition of recognizable infection, sampling of specimens for bacteriological investigations, bacteriologic techniques, and evaluation criteria were standardized. Patients were divided into 2 main groups. Patients in Group 1 received either a single intravenous dose of 1500 mg metronidazole or this dose was combined with a single, intravenous dose of 6 g ampicillin. Patients in group 2 received either a single intravenous dose of 1500 mg metronidazole or this dose combined with a single intravenous dose of 400 mg doxycycline. Dosage regimens were allocated randomly. The current results concern 136 patients. Postoperative infections were seen in 6.7% of the patients receiving metronidazole alone, and 2.9% of the patients receiving metronidazole + ampicillin (Group 1). In Group 2, postoperative infection occurred in 17.1% of the patients receiving metronidazole alone, and in 2.7% of those receiving metronidazole + doxycycline.