Role of peripheral sigma-1 receptors in ischaemic pain: Potential interactions with ASIC and P2X receptors.

BACKGROUND: The role of peripheral sigma-1 receptors (Sig-1Rs) in normal nociception and in pathologically induced pain conditions has not been thoroughly investigated. Since there is mounting evidence that Sig-1Rs modulate ischaemia-induced pathological conditions, we investigated the role of Sig-1Rs in ischaemia-induced mechanical allodynia (MA) and addressed their possible interaction with acid-sensing ion channels (ASICs) and P2X receptors at the ischaemic site. METHODS: We used a rodent model of hindlimb thrombus-induced ischaemic pain (TIIP) to investigate their role. Western blot was performed to observe changes in Sig-1R expression in peripheral nervous tissues. MA was measured after intraplantar (i.pl.) injections of antagonists for the Sig-1, ASIC and P2X receptors in TIIP rats or agonists of each receptor in naïve rats. RESULTS: Sig-1R expression significantly increased in skin, sciatic nerve and dorsal root ganglia at 3 days post-TIIP surgery. I.pl. injections of the Sig-1R antagonist, BD-1047 on post-operative days 0-3 significantly attenuated the development of MA during the induction phase, but had no effect on MA when given during the maintenance phase (days 3-6 post-surgery). BD-1047 synergistically increased amiloride (an ASICs blocker)- and TNP-ATP (a P2X antagonist)-induced analgesic effects in TIIP rats. In naïve rats, i.pl. injection of Sig-1R agonist PRE-084 alone did not produce MA; but it did induce MA when co-administered with either an acidic pH solution or a sub-effective dose of αßmeATP. CONCLUSION: Peripheral Sig-1Rs contribute to the induction of ischaemia-induced MA via facilitation of ASICs and P2X receptors. Thus, peripheral Sig-1Rs represent a novel therapeutic target for the treatment of ischaemic pain.

σ1 receptors activate astrocytes via p38 MAPK phosphorylation leading to the development of mechanical allodynia in a mouse model of neuropathic pain.

BACKGROUND AND PURPOSE: Spinal astrocytes have emerged as important mechanistic contributors to the genesis of mechanical allodynia (MA) in neuropathic pain. We recently demonstrated that the spinal sigma non-opioid intracellular receptor 1 (σ1 receptor) modulates p38 MAPK phosphorylation (p-p38), which plays a critical role in the induction of MA in neuropathic rats. However, the histological and physiological relationships among σ1, p-p38 and astrocyte activation is unclear. EXPERIMENTAL APPROACH: We investigated: (i) the precise location of σ1 receptors and p-p38 in spinal dorsal horn; (ii) whether the inhibition of σ1 receptors or p38 modulates chronic constriction injury (CCI)-induced astrocyte activation; and (iii) whether this modulation of astrocyte activity is associated with MA development in CCI mice. KEY RESULTS: The expression of σ1 receptors was significantly increased in astrocytes on day 3 following CCI surgery. Sustained intrathecal treatment with the σ1 antagonist, BD-1047, attenuated CCI-induced increase in GFAP-immunoreactive astrocytes, and the treatment combined with fluorocitrate, an astrocyte metabolic inhibitor, synergistically reduced the development of MA, but not thermal hyperalgesia. The number of p-p38-ir astrocytes and neurons, but not microglia was significantly increased. Interestingly, intrathecal BD-1047 attenuated the expression of p-p38 selectively in astrocytes but not in neurons. Moreover, intrathecal treatment with a p38 inhibitor attenuated the GFAP expression, and this treatment combined with fluorocitrate synergistically blocked the induction of MA. CONCLUSIONS AND IMPLICATIONS: Spinal σ1 receptors are localized in astrocytes and blockade of σ1 receptors inhibits the pathological activation of astrocytes via modulation of p-p38, which ultimately prevents the development of MA in neuropathic mice.

Comparison of the clinical characteristics of renal transplant recipients who underwent early versus late graft nephrectomy.

BACKGROUND: Graft nephrectomy is the last-resort option for renal transplant recipients. The aim of this study was to compare the clinical characteristics of patients who underwent graft nephrectomy according to the time after renal transplantation. METHODS: From 2005 to 2012, 42 patients underwent graft nephrectomy after transplant failure. We divided these patients into early (n = 17) and late graft nephrectomy (n = 25) groups based on graft survival to 6 months, comparing their causes for nephrectomy and clinical characteristics. RESULTS: The patients included 29 men and 13 women, with an overall mean age of 45 years (range, 10-71 years). The main causes for early and late graft nephrectomy were irreversible acute rejection (71%) and graft intolerance syndrome (95%), respectively. The clinical characteristics did not significantly differ between the early and late graft nephrectomy groups except for operative-related complications. Bleeding was more common among patients who underwent early (n = 10) versus late (n = 3) graft nephrectomy (59% vs 12%; P = .01). Of the 10 patients with perioperative bleeding, 8 had a bleeding tendency, such as low platelet count or prolonged prothrombin time at the time of the operation. These complications occurred after antirejection therapy involving plasma exchange or antithymocyte globulin treatment. Allograft nephrectomy was associated with a mortality rate of 2.38%. CONCLUSIONS: The cause for graft nephrectomy and type of perioperative complication differed according to timing of graft nephrectomy. Antirejection therapy appeared to contribute to postoperative complications such as bleeding.

Clinical usefulness of 3-dimensional computerized tomographic renal angiography to detect transplant renal artery stenosis.

OBJECTIVE: The aim of this study was to evaluate whether 3-dimensional computerized tomographic angiography (3D-CTA) is useful to detect transplant renal artery stenosis (TRAS). METHODS: Fourteen patients with clinically suspected TRAS underwent color Doppler ultrasonography (CDU) and 3D-CTA before renal angiography. We compared 3D-CTA and CDU for accuracy based on the results of renal angiography. The safety of 3D-CTA was investigated by measuring the estimated glomerular filtration rate (eGFR) before and after the 3D-CTA examination. RESULTS: The 10 men and 4 women who participated in this study showed a mean eGFR of 75 mL/min/1.73 m(2) (range 60-94). Of these, 9 patients were diagnosed with TRAS. 3D-CTA detected stenoses in all 9 patients, but CDU failed to detect it in 3, including, 2 with end-to-side arterial anastomoses, which may be more challenging to detect compared with end-to-end anastomoses. The stenotic area in 3D-CTA was similar to that detected by renal angiography (70 ± 12 vs 68 ± 11). The eGFR did not differ significantly before versus after the 3D-CTA examination; 72 ± 13 vs 69 ± 14 mL/min/1.73 m(2). CONCLUSIONS: 3D-CTA was an effective safe method to detect renal artery stenosis among transplant recipients with an eGFR >60 mL/min/1.73 m(2).

The role of kidney biopsy to determine donation from prospective kidney donors with asymptomatic urinary abnormalities.

BACKGROUND: There are no definite guidelines about donation among prospective donors with asymptomatic urinary abnormalities. We evaluated the pathology of prospective kidney donors with asymptomatic urinary abnormalities and assessed the clinical outcomes of their organs. METHODS: We reviewed the medical records of 15 prospective kidney donors who underwent kidney biopsy. We evaluated the role of kidney biopsy in terms of graft function, protocol biopsy, and follow-up biopsy. We further assessed the clinical outcomes of donors and recipients. RESULTS: Thin basement membrane nephropathy (TBMN) is the most common cause of the persistent microscopic hematuria (n = 7; 50%), followed by nonspecific findings (n = 4; 29%), IgA nephropathy (n = 2; 14%), and focal segmental glomerulosclerosis (n = 1; 7%). Of the 14 candidate donors with persistent microscopic hematuria, 9 were accepted as kidney donors: 5 with TBMN, 3 with mild mesangiopathy, and 1 with nonspecific interstitial changes. The function of the 9 grafts was relatively stable (mean serum creatinine level 2.38 mg/dL) over a mean follow-up of 57 months. Graft failure that developed in 2 grafts was not associated with biopsy findings: acute rejection and patient death with a functioning graft. Interestingly, basement membrane thickness in 2 allografts from donors with TBMN appeared normal by electron microscopy follow-up biopsy; the allografts did not show hematuria. Moreover, the clinical outcomes of donors were favorable (mean serum creatinine 0.94 ± 0.32 mg/dL) during the mean follow-up period of 34.7 ± 42.5 months. We did not observe new-onset hypertension or proteinuria in donors. CONCLUSIONS: Kidney biopsy in prospective kidney donors with urinary abnormalities is a safe and effective diagnostic procedure to stratify candidates. Therefore, kidney biopsy should be actively performed to improve the prognosis of both donors and recipients.

Delayed graft function in living-donor renal transplantation: 10-year experience.

BACKGROUND: Delayed graft function (DGF), a dialysis requirement within a week after transplantation, can occur in deceased-donor renal transplantation. DGF is rare, in living-donor renal transplantation (LDRT) and its incidence and risk factors have not been established. METHODS: We investigated the incidence and clinical characteristics of DGF in LDRT over 10 years. We compared HLA mismatches, panel reactive antibody status, frequency of nonrelated donors, donor age, sex match, recipient-donor body weight ratio, total ischemia time, and transplanted kidney weight between DGF and non-DGF patients. RESULTS: The incidence of DGF in LDRT was 1.6%, which differed from earlier reports. HLA mismatch, female recipient frequency, and nonrelated donors were higher among the DGF group, but no risk factor for DGF was significant after multivariate logistic regression analysis. Biopsy findings showed 2 cases to be associated with rejection, 1 with acute pyelonephritis and 1 with acute tubular necrosis. The cases with rejection resulted in graft failure within 3 years after transplantation, but the other cases were followed with favorable graft function. CONCLUSIONS: The incidence of DGF among LDRT was lower than that reported earlier studies, and the factors previously reported to cause DGF were not associated with DGF herein. Because DGF with rejection responses has a poor prognosis, strenuous strategies, including biopsy, should be performed in cases of DGF after LDRT.

Effectiveness of rituximab and intravenous immunoglobulin therapy in renal transplant recipients with chronic active antibody-mediated rejection.

BACKGROUND: Chronic active antibody-mediated rejection (CAMR) is an important cause of chronic kidney allograft dysfunction, but there has been no effective treatment protocol established for it. METHODS: Six renal transplant recipients who showed progressive deterioration in graft function and CAMR as diagnosed by biopsy were enrolled. We administered a single dose of rituximab (375 mg/m(2)), followed by intravenous immunoglobulin (IVIg, 0.4 g/kg) for 4 days. The efficacy of this protocol was assessed on the basis of the improvement in allograft function, the amount of proteinuria, and the change in donor-specific antibodies (DSAs). We categorized the patients into 2 groups, responders and nonresponders, according to their response to the treatment. RESULTS: All of the patients showed progressive deterioration of graft function before the diagnosis of CAMR. Luminex solid-phase assays showed that 3 patients had DSAs. After the treatment, allograft function improved or stabilized in 3 patients in the responder group, but still showed a deteriorating pattern in the nonresponder group. In the responder group, the amount of proteinuria also decreased after the treatment, but it increased in the nonresponder group. On diagnosis of CAMR, the nonresponders showed a longer posttransplantation period, a higher degree of transplant glomerulopathy, more severely deteriorated allograft function, and higher proteinuria compared with the responders. CONCLUSIONS: The combination of rituximab and IVIg was effective in early-stage CAMR, but the effect was limited in the advanced stage.

Spectral entropy monitoring allowed lower sevoflurane concentration and faster recovery in children.

BACKGROUND: Anesthetic titration using spectral entropy monitoring reduces anesthetic requirements and shortens recovery in adult surgical patients. This study was performed to evaluate the effect of entropy monitoring on end-tidal sevoflurane concentration and recovery characteristics in pediatric patients undergoing sevoflurane anesthesia. METHODS: Seventy-eight children (aged 3-12 years) scheduled for a tonsillectomy and/or an adenoidectomy were randomly divided into one of two groups: standard practice (Standard) or entropy-guided (Entropy). In the Standard group, sevoflurane was adjusted to maintain the heart rate and systolic blood pressure (BP) within 20% of the baseline values. In the Entropy group, sevoflurane was adjusted to achieve a state entropy of 40-50. We compared the entropy values, end-tidal sevoflurane concentration and recovery times between groups. RESULTS: During maintenance of anesthesia, the entropy and BP values were higher in the Entropy group (P<0.05). The end-tidal sevoflurane concentration during maintenance was lower in the Entropy group (2.2 (0.3) vol%) compared with the Standard group (2.6 (0.4) vol%) (P<0.05). Recovery times were faster in the Entropy group (P<0.05). CONCLUSIONS: Compared with standard practice, we found that entropy-guided anesthetic administration was associated with a reduced sevoflurane concentration and a slightly faster emergence and recovery in 3-12-year-old children.

Role of heat shock proteins in gastric inflammation and ulcer healing.

With the discovery of gastric acid and pepsin in the stomach, the questions about "why does the stomach not digest itself?", "how does the stomach preserve its normal integrity under the continuous exposure to lytic materials that are secreted?", and "how does the stomach resist against overwhelming Helicobacter pylori (H. pylori) infection or persistent nonsteroidal anti-inflammatory drugs (NSAID) administration?" had been raised. The discovery of "gastric mucosal barrier" or "the presence of defense system" might be the answers to these questions. The first level of gastric mucosal barrier consists of the factors secreted into the lumen including bicarbonates, mucus, immunoglobulins, other antibacterial substances including lactoferrin, and surface active phospholipids. The second level of defense system is the gastric epithelia, which are remarkably resistant to acids or irritants and forms relatively tight barrier to passive diffusion. In addition, the epithelium is capable of undergoing extremely rapid repair and restitution if its continuity is disrupted. The third level of gastric mucosal barrier is the mucosal microcirculation in concert with sensory afferent nerves within the mucosa and submucosa. Back diffusion of acid or toxin into the mucosa results in neural system-mediated elevations of calcitonin gene related peptide, which contribute to enhancing mucosal blood flows that are very critical for limiting damage and facilitating repair. The fourth level of defense is the mucosal immune system, consisting of mast cells and macrophage, which orchestrate an appropriate inflammatory response to challenge. All the above factors are known to contribute to orchestrated artwork of "gastric mucosal protection". In recent years, heat shock proteins (HSPs) have been implicated to be an additional factor utilized for the gastric defense mechanisms at the intracellular level. Certain HSPs are expressed under non-stressful conditions and play an important role in the maintenance of normal cell integrity, but HSPs are generally considered to improve cellular recovery both by either refolding partially damaged functional proteins or increasing delivery of precursor proteins to important organelles such as mitochondria and endoplasmic reticulum, through which HSPs might complete efficient mucosal defense mechanisms and achieve ulcer healing, mostly probably protecting key enzymes related to cytoprotection. In this review, role of each heat shock protein, HSP90, HSP70, HSP27, in gastric inflammation and gastric ulcer healing will be described with general roles of HSPs.

Effect of remifentanil on oculocardiac reflex in paediatric strabismus surgery.

BACKGROUND: Rapidly acting narcotics enhance the degree of bradycardia due to the oculocardiac reflex (OCR) elicited by extraocular muscle (EOM) tension during strabismus surgery. We evaluated and compared the effects of remifentanil and sevoflurane on OCR during paediatric strabismus surgery. METHODS: One hundred and twenty children, 1-9 years old, undergoing elective strabismus surgery, were randomly assigned to receive sevoflurane or remifentanil. No anticholinergic prophylaxis was administered. Anaesthesia was induced using ketamine 1.0 mg/kg or midazolam 0.15 mg/kg with 66% N(2)O in O(2). Laryngeal mask airways were placed with rocuronium 0.5 mg/kg. Anaesthesia was maintained with sevoflurane 2.0-3.0 vol% with 66% N(2)O in O(2) or remifentanil 0.75 mug/kg over 1 min and followed by the continuous infusion of remifentanil 0.5 mug/kg/min with 66% N(2)O in O(2). Heart rate (HR) and blood pressure (BP) were measured and compared. OCR was defined as a reduction in HR of >20% induced by traction of an EOM. RESULTS: During anaesthesia, HR and BP were maintained at a lower level in the remifentanil group than in the sevoflurane group (each, P<0.05). The mean percent change in HR (-23.3+/-17.0% vs. -11.2+/-13.0%; P<0.05) and the incidence of OCR (58.3% vs. 28.3%; P<0.05) following traction of an EOM were higher in the remifentanil group than in the sevoflurane group. CONCLUSIONS: Remifentanil enhanced the degree of bradycardia due to OCR as compared with sevoflurane during paediatric strabismus surgery.

Flowering time quantitative trait Loci analysis of oilseed brassica in multiple environments and genomewide alignment with Arabidopsis.

Most agronomical traits exhibit quantitative variation, which is controlled by multiple genes and are environmentally dependent. To study the genetic variation of flowering time in Brassica napus, a DH population and its derived reconstructed F(2) population were planted in 11 field environments. The flowering time varied greatly with environments; 60% of the phenotypic variation was attributed to genetic effects. Five to 18 QTL at a statistically significant level (SL-QTL) were detected in each environment and, on average, two new SL-QTL were discovered with each added environment. Another type of QTL, micro-real QTL (MR-QTL), was detected repeatedly from at least 2 of the 11 environments; resulting in a total of 36 SL-QTL and 6 MR-QTL. Sixty-three interacting pairs of loci were found; 50% of them were involved in QTL. Hundreds of floral transition genes in Arabidopsis were aligned with the linkage map of B. napus by in silico mapping; 28% of them aligned with QTL regions and 9% were consistent with interacting loci. One locus, BnFLC10, in N10 and a QTL cluster in N16 were specific to spring- and winter-cropped environments respectively. The number of QTL, interacting loci, and aligned functional genes revealed a complex genetic network controlling flowering time in B. napus.

Laparoscopic wedge resection for gastric GIST: long-term follow-up results.

AIM: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal tract. Recently, many investigations have been conducted on various aspects of laparoscopic surgery for gastric GIST. However, no study has provided long-term follow up results of laparoscopic surgery for gastric GIST. The aims of this study were to assess the feasibility and safety of laparoscopic surgery for gastric GIST and to evaluate the oncologic validity of the procedure. MATERIALS AND METHODS: Between January 1998 and August 2005, 51 patients with submucosal tumor of the stomach were treated by laparoscopic surgery at our institution. Of 51 patients, 23 patients were confirmed as gastric GIST by immunohistochemistry (CD 117, c-kit gene product). Patients' clinicopathologic characteristics, operative outcomes, postoperative complications, and follow-up findings were analyzed retrospectively. RESULTS: The mean age of patients was 59.7 years, and 12 patients were women. Twelve patients (47%) presented with epigastric pain. The mean tumor size was 4.2+/-2.1 cm, and most tumors were located in the upper stomach (52.2%). The mean operative time was 104.3 min. No case of open conversion, reoperation and operative mortality occurred in the present study. Most patients had very low and low risk (60.6%), while only two patients had high risk malignancy. During a median follow-up period of 61 months (range, 7-98 months), there have been no recurrences or metastases. CONCLUSION: Laparoscopic wedge resection for gastric GIST is safe, and oncologically and technically feasible in the hands of an experienced laparoscopic gastric surgeon.

New insight of amino acid-based dialysis solutions.

Malnutrition is a major complication of peritoneal dialysis (PD) and is associated with increased morbidity and mortality. Daily losses of proteins and amino acids (AAs) into dialysate contribute to this problem. Previous metabolic balance study demonstrated that treatment with 1.1% AA-based dialysis solution is safe and may improve protein malnutrition in continuous ambulatory peritoneal dialysis (CAPD) patients ingesting low protein intake. Other prospective studies also showed that AA solution can provide nutritional benefit for malnourished PD patients resulting in a significant improvement in some biochemical and/or anthropometric nutritional parameters. However, there are other studies showing no particular improvement in nutritional parameters after long-term use of AA solution. This may be related to the differences in the study design, sample size, methods used to assess nutritional status, and other factors such as dietary intake and comorbidities of study subjects. Published data will be reviewed to further emphasize the nutritional benefit of long-term use of AA solution in malnourished PD patients along with a brief discussion on the various reasons that may partly explain the different study results. We will also present the results of a longitudinal observational study evaluating changes in nutritional parameters following use of one exchange of 1.1% AA solution in malnourished Korean PD patients. A significant improvement of somatic protein status such as lean body mass (LBM) and hand grip strength was observed. No significant change in serum albumin level was noted. Patients with a positive estimated coefficient for LBM in the fitted regression model to the repeated observations over 1 year were classified as responders and patients with neutral or negative coefficient were considered as non-responders. Thirty-one out of 43 malnourished patients (72%) showed nutritional benefit based on the change of LBM. Hand grip strength and back lift strength were significantly higher in responders at baseline. Other baseline parameters did not differ between the two groups.

Construction of a BAC library of Korean ginseng and initial analysis of BAC-end sequences.

We estimated the genome size of Korean ginseng (Panax ginseng C.A. Meyer), a medicinal herb, constructed a HindIII BAC library, and analyzed BAC-end sequences to provide an initial characterization of the library. The 1C nuclear DNA content of Korean ginseng was estimated to be 3.33 pg (3.12 x 10(3) Mb). The BAC library consists of 106,368 clones with an average size of 98.61 kb, amounting to 3.34 genome equivalents. Sequencing of 2167 BAC clones generated 2492 BAC-end sequences with an average length of 400 bp. Analysis using BLAST and motif searches revealed that 10.2%, 20.9% and 3.8% of the BAC-end sequences contained protein-coding regions, transposable elements and microsatellites, respectively. A comparison of the functional categories represented by the protein-coding regions found in BAC-end sequences with those of Arabidopsis revealed that proteins pertaining to energy metabolism, subcellular localization, cofactor requirement and transport facilitation were more highly represented in the P. ginseng sample. In addition, a sequence encoding a glucosyltransferase-like protein implicated in the ginsenoside biosynthesis pathway was also found. The majority of the transposable element sequences found belonged to the gypsy type (67.6%), followed by copia (11.7%) and LINE (8.0%) retrotransposons, whereas DNA transposons accounted for only 2.1% of the total in our sequence sample. Higher levels of transposable elements than protein-coding regions suggest that mobile elements have played an important role in the evolution of the genome of Korean ginseng, and contributed significantly to its complexity. We also identified 103 microsatellites with 3-38 repeats in their motifs. The BAC library and BAC-end sequences will serve as a useful resource for physical mapping, positional cloning and genome sequencing of P. ginseng.

SCAR and CAPS mapping of CRb, a gene conferring resistance to Plasmodiophora brassicae in Chinese cabbage ( Brassica rapa ssp. pekinensis).

Clubroot disease, caused by Plasmodiophora brassicae Wor., is highly damaging for Chinese cabbage. The CR (clubroot resistant) Shinki DH (doubled haploid) line of Chinese cabbage carries a single dominant gene, CRb, which confers resistance to the P. brassicae races 2, 4, and 8. An F(2) population derived from a cross between the CR Shinki DH line and a susceptible line, 94SK, was used to map the CRb gene. Inoculation of F(3) families with SSI (single-spore isolate) resulted in a 1:2:1 segregation ratio. Use of the AFLP technique combined with bulked segregant analysis allowed five co-dominant AFLP markers, and four and seven dominant AFLP markers linked in coupling and repulsion, respectively, to be identified. Six of the 16 AFLP markers showing low frequencies of recombination with the CRb locus among 138 F(2) lines were cloned. A reliable conversion procedure allowed five AFLP markers to be successfully converted into CAPS and SCAR markers. An F(2) population (143 plants) was analyzed with these markers and a previously identified SCAR marker, and a genetic map around CRb covering a total distance of 6.75 cM was constructed. One dominant marker, TCR09, was located 0.78 cM from CRb. The remaining markers (TCR05, TCR01, TCR10, TCR08, and TCR03) were located on the other side of CRb, and the nearest of these was TCR05, at a distance of 1.92 cM.

Quantification of serotonin transporters in nonhuman primates using [(123)I]ADAM and SPECT.

UNLABELLED: We reported recently a highly selective radioligand, 2-([2-([dimethylamino]methyl)phenyl]thio)-5-[(123)I]iodophenylamine (ADAM), for SPECT imaging of serotonin transporters (SERT). In this article we describe the kinetic modeling of [(123)I]ADAM and its ability to quantitatively and reproducibly measure the concentrations of SERT in the nonhuman primate brain. We also investigate simplified models of tracer behavior that do not require invasive arterial blood sampling. METHODS: Three female baboons each underwent 3 [(123)I]ADAM SPECT studies. The studies consisted of a dynamic sequence of seventy-two 5-min scans after injection of 330 +/- 50 MBq (mean +/- SD) [(123)I]ADAM. Rapid arterial blood samples were obtained and corrected for the presence of labeled metabolites. Dynamic imaging and metabolite-corrected plasma data were analyzed using graphic analysis to give the distribution volumes (DVs) of different brain regions. DV ratios (DVRs) of target to cerebellum were derived and compared against a kinetic reference tissue model and simple target-to-background ratio. RESULTS: Averaged over all 9 scans, the mean DV in the midbrain was 4.86 +/- 1.06 mL/mL and the mean DV in the cerebellum was 2.25 +/- 0.48 mL/mL. The mean test-retest repeatability of the midbrain DV was 14.5%. The reference tissue model gave a mean midbrain DVR of 2.01 +/- 0.17 and correlated strongly with the DVR calculated from the full kinetic model (correlation coefficient [R(2)] = 0.94; P < 0.001), but with much improved repeatability (test-retest, 5.4%; intersubject variability, 5.2%). Similarly, the simple ratio method gave strong correlations with the full kinetic model (R(2) = 0.89; P < 0.001) and a test-retest of 7.6%. CONCLUSION: Accurate, repeatable quantification of SERT in the nonhuman primate brain is possible using kinetic modeling of dynamic [(123)I]ADAM SPECT scans. Simplified models, which do not require arterial blood sampling, gave accurate results that correlated strongly with the full kinetic model. The test-retest reliability of the simplified reference region models was excellent. Quantification of SERT is possible using full kinetic modeling and also with simpler reference region methods.

Development of a Tc-99m labeled sigma-2 receptor-specific ligand as a potential breast tumor imaging agent.

A novel in vivo imaging agent, 99mTc labeled [(N-[2-((3'-N'-propyl-[3,3,1]aza-bicyclononan-3alpha-yl)(2"-methoxy-5-methyl-phenylcarbamate)(2-mercaptoethyl)amino)acetyl]-2-aminoethanethiolato] technetium(V) oxide), [99mTc]2, displaying specific binding towards sigma-2 receptors was prepared and characterized. In vitro binding assays showed that the rhenium surrogate of [99mTc]2, Re-2, displayed excellent binding affinity and selectivity towards sigma-2 receptors (K(i) = 2,723 and 22 nM for sigma-1 and sigma-2 receptor, respectively). Preparation of [99mTc]2 was achieved by heating the S-protected starting material, 1, in the presence of acid, reducing agent (stannous glucoheptonate) and sodium [99mTc]pertechnetate. The lipophilic racemic mixture was successfully prepared in 10 to 50% yield and the radiochemical purity was >98%. Separation of the isomers, peak A and peak B, was successfully achieved by using a chiralpak AD column eluted with an isocratic solvent (n-hexane/isopropanol; 3:1; v/v). The peak A and peak B appear to co-elute with the isomers of the surrogate, Re-2, under the same HPLC condition. Biodistribution studies in tumor bearing mice (mouse mammary adenocarcinoma, cell line 66, which is known to over-express sigma-2 receptors) showed that the racemic [99mTc]2 localized in the tumor. Uptake in the tumor was 2.11, 1.30 and 1.11 %dose/gram at 1, 4 and 8 hr post iv injection, respectively, suggesting good uptake and retention in the tumor cells. The tumor uptake was significantly, but incompletely, blocked (about 25-30% blockage) by co-injection of "cold" (+)pentazocine or haloperidol (1 mg/Kg). A majority of the radioactivity localized in the tumor tissue was extractable (>60%), and the HPLC analysis showed that it is the original compound, racemic [99mTc]2 (>98% pure). The distribution of the purified peak A and peak B was determined in the same tumor bearing mice at 4 hr post iv injection. The tumor uptake was similar for both isomers, but the blood and peripheral tissue content for the isomer in peak B was higher than that for the isomer in peak A. It is evident that the isomer in peak A displayed significantly better tumor/blood and tumor/muscle ratios. The higher rate of in vivo metabolism was also confirmed by the higher thyroid uptake values for the isomer in peak B as compared to peak A. In summary, a 99mTc-labeled sigma receptor imaging agent, [99mTc]2, has demonstrated the feasibility of using a 99mTc-labeled agent for imaging sigma receptor expression in tumor cells. This is the first time a subtype-selective 99mTc-labeled agent for imaging sigma receptor sites is reported.

Hyperbaric spinal ropivacaine for cesarean delivery: a comparison to hyperbaric bupivacaine.

UNLABELLED: We evaluated the clinical efficacy and safety of spinal anesthesia with 0.5% hyperbaric ropivacaine compared with 0.5% hyperbaric bupivacaine for elective cesarean delivery. Sixty healthy, full-term parturients were randomly assigned to receive either 12 mg of 0.5% hyperbaric bupivacaine or 18 mg of 0.5% hyperbaric ropivacaine intrathecally. There were no significant differences in demographic or surgical variables or neonatal outcomes between groups. Onset time of sensory block to T10 or to peak level was later in the Ropivacaine group (P < 0.05). The median (range) peak level of analgesia was T3 (T1-5) in the Bupivacaine group and T3 (T1-4) in the Ropivacaine group. Time for sensory block to recede to T10 did not differ between groups. Duration of sensory block was shorter in the Ropivacaine group (188.5 +/- 28.2 min vs 162.5 +/- 20.2 min; P < 0.05). Complete motor block of the lower extremities was obtained in all patients. Ropivacaine also produced a shorter duration of motor blockade than bupivacaine (113.7 +/- 18.6 min vs 158.7 +/- 31.2 min; P < 0.000). The intraoperative quality of anesthesia was excellent and similar in both groups. Side effects did not differ between groups. Eighteen milligrams of 0.5% hyperbaric ropivacaine provided effective spinal anesthesia with shorter duration of sensory and motor block, compared with 12 mg of 0.5% hyperbaric bupivacaine when administered for cesarean delivery IMPLICATIONS: Eighteen milligrams of 0.5% hyperbaric ropivacaine provided effective spinal anesthesia with shorter duration of sensory and motor block, compared with 12mg of 0.5% hyperbaric bupivacaine when administered for cesarean delivery.

Selective in vitro and in vivo binding of [(125)I]ADAM to serotonin transporters in rat brain.

An improved iodinated tracer, ADAM (2-((2-((dimethylamino)methyl)- phenyl)thio)-5-iodophenylamine) for imaging serotonin transporters (SERT) with single photon emission computerized tomography (SPECT), was prepared and characterized. Scatchard analysis of saturation binding of [(125)I]ADAM to rat frontal cortical membrane homogenates gave a K(d) value of 0.15 +/- 0.03 nM and a B(max) value of 194 +/- 65 fmol/mg protein. Biodistribution of [(125)I]ADAM in rat brain after an iv injection showed a high specific binding in the regions of hypothalamus, cortex, striatum, and hippocampus, where SERT are concentrated and the specific binding peaked at 120-240 min postinjection [(hypothalamus-cerebellum)/cerebellum = 4.3 at 120 min post-iv injection]. Moreover, the specific hypothalamic uptake was blocked by pretreatment with SERT selective competing drugs, such as paroxetine and (+)McN5652, while other noncompeting drugs, such as ketanserin, raclopride, and methylphenidate, showed no effect. The radioactive material recovered from rat brain homogenates at 120 min after [(125)I]ADAM injection showed primarily the original compound (>90%), a good indication of in vivo stability in the brain tissues. Both male and female rats showed similar and comparable organ distribution pattern and regional brain uptakes. Ex vivo autoradiograms of rat brain sections (120 min after iv injection of [(125)I]ADAM) showed intense labeling in several regions (olfactory tubercle, lateral septal nucleus, hypothalamic and thalamic nuclei, globus pallidus, central gray, superior colliculus, substantia nigra, interpeduncular nucleus, dorsal and median raphes, and locus coerulus), which parallel known SERT density. These results strongly suggest that the novel tracer ADAM is superior to the congers (i.e., IDAM) reported previously. When labeled with I-123, ADAM will be an improved and useful SPECT imaging agent for SERT in the brain.