New Antimuscarinic Agents for Improved Treatment of Poisoning by Cholinesterase Inhibitors

Poisoning by organophosphate cholinesterase inhibitors results in a rapid rise in acetylcholine (ACh) in the synapse and many pronounced pharmacological effects in numerous tissues in the body. The treatment for organophosphorus poisoning involves administration of a cholinesterase—reactivating oxime to restore the activity of the cholinesterase and an antimuscarinic agent to block the response to the excess ACh. Presently atropine is the standard antimuscarinic agent used clinically as an antidote. This research was directed toward finding an antimuscarinic agent better than atropine as an antidote. Since caramiphen and aprophen have been reported to be effective antidotes we synthesized numerous structural variations of these molecules with the aim of enhancing the antimuscarinic and antidotal properties. Many of these compounds showed enhanced antimuscarinic properties. We synthesized analogs of caramiphen which have different substituents in the para position of the phenyl ring. The purpose of the set was to test the effect of different substituents on the antimuscarinic and antidotal activity and to look for any possible relationship of activity with substituent parameters such as Hammett’s sigma (σ) or Hansch’s pi (π) values. Four substituents were selected which have extreme values for sigma and pi in a positive or negative direction, in all combinations. The substituents chosen for use in this approach were the amino (-σ, -π); 1-‘ tetrazolyl (+σ, -π); l-pyrrolidinyl (-σ, +π); and the trifluoromethyl (+σ, +π). Some N-substituted-1,6-hexanediamines were synthesized to examine the SAR for antimuscarinic and antidotal properties of this series. In a binding assay these compounds showed moderate affinity with a preference for the M2 receptor subtype. It was determined the bis-quaternary structure was not mandatory for muscarinic activity. The optimum compound of this series was N,N’-dimethyl-N,N’-bis[3-(2- phthalimido)propyl]-1,6-hexanediamine. Also, a number of literature and currently manufactured antimuscarinics were obtained. All of the compounds are being screened in a number of in vitro and in vivo assays designed to give information on the SAR for the pharmacological properties which might be important as an antidote. Current information from this research indicates the best antidotes are not the best antimuscarinics in the pharmacological assays. Good central antimuscarinic activity is the primary property of a good antidote, although the antidotal effectiveness of an agent can not be described solely based on its antimuscarinic properties

Hyperglycemia and Hyperlipidemia Act Synergistically to Induce Renal Disease in LDL Receptor-Deficient BALB Mice

Diabetic nephropathy is the leading cause of end-stage renal disease in Western countries, but only a portion of diabetic patients develop diabetic nephropathy. Dyslipidemia represents an important aspect of the metabolic imbalance in diabetic patients. In this study, we addressed the impact of combined hyperlipidemia and hyperglycemia on renal pathology. Kidneys from wildtype (WT) or LDL receptor-deficient BALB/cBy mice (BALB. LDLR -/-) were examined at 22 weeks of age. Diabetes was induced by administration of streptozotocin and mice were randomly assigned to either standard chow or Western diet. Chow fed BALB. LDLR -/- mice did not demonstrate renal abnormalities, whereas BALB. LDLR -/- mice fed a Western diet showed occasional glomerular and tubulointerstitial foam cells. Diabetic WT mice had modestly increased glomerular cellularity and extracellular matrix. Hyperlipidemic and diabetic BALB. LDLR -/- mice exhibited an increase in glomerular cellularity and extracellular matrix, accumulation of glomerular and tubulointerstitial foam cells and mesangial lipid deposits. The tubular epithelium demonstrated pronounced lipid induced tubular degeneration with increased tubular epithelial cell turnover. Hyperlipidemia and hyperglycemia seem to act synergistically in inducing renal injury in the BALB. LDLR-/- mouse. This model of diabetic nephropathy is unique in its development of tubular lesions and may represent a good model for hyperlipidemia-exacerbated diabetic nephropathy. Copyright (C) 2004 S. Karger AG, Basel

Loperamide Inhibits Replication of Severe Fever with Thrombocytopenia Syndrome Virus

Background: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease caused by the SFTS virus (SFTSV). SFTS is mainly prevalent in East Asia. It has a mortality rate of up to 30%, and there is no approved treatment against the disease. In this study, we evaluated the effect of loperamide, an antidiarrheal and antihyperalgesic agent, on the propagation of SFTSV in a cell culture system. Methods: SFTSV-infected human cell lines were exposed to loperamide, and viral titers were evaluated. To clarify the mode of action of loperamide, several chemical compounds having shared targets with loperamide were used. Calcium imaging was also performed to understand whether loperamide treatment affected calcium influx.Results: Loperamide inhibited SFTSV propagation in several cell lines. It inhibited SFTSV in the post-entry step and restricted calcium influx into the cell. Furthermore, nifedipine, a calcium channel inhibitor, also blocked post-entry step of SFTSV infection.Conclusions: Loperamide inhibits SFTSV propagation mainly by restraining calcium influx into the cytoplasm. This indicates that loperamide, a Food and Drug Administration (FDA)-approved drug, has the potential for being used as a treatment option against SFTS

White-matter abnormalities in brain during early abstinence from methamphetamine abuse

Previous studies revealed microstructural abnormalities in prefrontal white matter and corpus callosum of long-term abstinent chronic methamphetamine abusers. In view of the importance of the early abstinence period in treatment retention, we compared 23 methamphetamine-dependent subjects abstinent from methamphetamine for 7–13 days with 18 healthy comparison subjects. As certain metabolic changes in the brain first manifest after early abstinence from methamphetamine, it is also possible that microstructural white-matter abnormalities are not yet present during early abstinence. Using diffusion tensor imaging at 1.5 T, fractional anisotropy (FA) was measured in prefrontal white matter at four inferior–superior levels parallel to the anterior commissure–posterior commissure (AC–PC) plane. We also sampled FA in the corpus callosum at the midline and at eight bilateral, fiber-tract sites in other regions implicated in effects of methamphetamine. The methamphetamine group exhibited lower FA in right prefrontal white matter above the AC–PC plane (11.9% lower; p = 0.007), in midline genu corpus callosum (3.9%; p = 0.019), in left and right midcaudal superior corona radiata (11.0% in both hemispheres, p’s = 0.020 and 0.016, respectively), and in right perforant fibers (7.3%; p = 0.025). FA in left midcaudal superior corona radiata was correlated with depressive and generalized psychiatric symptoms within the methamphetamine group. The findings support the idea that methamphetamine abuse produces microstructural abnormalities in white matter underlying and interconnecting prefrontal cortices and hippocampal formation. These effects are already present during the first weeks of abstinence from methamphetamine and are linked to psychiatric symptoms assessed during this period

Localization of PDGF α-receptor in the developing and mature human kidney

Localization of PDGF α-receptor in the developing and mature human kidney. Using in situ hybridization and immunocytochemistry we describe the renal localization of the PDGF α-receptor. PDGF α-receptor mRNA was uniformly present in human metanephric kidney in interstitial cells and vascular arcades that course through the blastema. PDGF α-receptor mRNA was present in some mesangial structures in early glomeruli, but was largely lost as glomeruli matured. It was present in adventitial fibroblasts, but usually not in vascular smooth muscle cells or endothelial cells of the fetal vasculature. This pattern persisted in adult kidneys, with extensive expression of mRNA by interstitial cells and only occasional expression by mesangial cells. All in situ hybridization findings were corroborated by immunocytochemistry. Double immunolabeling confirmed the rare expression of the PDGF α-receptor protein by vascular smooth muscle cells and the absence of its expression by endothelial cells. Given that both PDGF A- and B-chain can promote smooth muscle cell and fibroblast migration and proliferation and that both signal through the PDGF α-receptor, these data suggest that PDGF α-receptor may play important roles in the early vasculogenesis of the fetal kidney as well as in the pathogenesis of renal interstitial fibrosis

Lung cancer induced in mice by the envelope protein of jaagsiekte sheep retrovirus (JSRV) closely resembles lung cancer in sheep infected with JSRV

BACKGROUND: Jaagsiekte sheep retrovirus (JSRV) causes a lethal lung cancer in sheep and goats. Expression of the JSRV envelope (Env) protein in mouse lung, by using a replication-defective adeno-associated virus type 6 (AAV6) vector, induces tumors resembling those seen in sheep. However, the mouse and sheep tumors have not been carefully compared to determine if Env expression alone in mice can account for the disease features observed in sheep, or whether additional aspects of virus replication in sheep are important, such as oncogene activation following retrovirus integration into the host cell genome. RESULTS: We have generated mouse monoclonal antibodies (Mab) against JSRV Env and have used these to study mouse and sheep lung tumor histology. These Mab detect Env expression in tumors in sheep infected with JSRV from around the world with high sensitivity and specificity. Mouse and sheep tumors consisted mainly of well-differentiated adenomatous foci with little histological evidence of anaplasia, but at long times after vector exposure some mouse tumors did have a more malignant appearance typical of adenocarcinoma. In addition to epithelial cell tumors, lungs of three of 29 sheep examined contained fibroblastic cell masses that expressed Env and appeared to be separate neoplasms. The Mab also stained nasal adenocarcinoma tissue from one United States sheep, which we show was due to expression of Env from ovine enzootic nasal tumor virus (ENTV), a virus closely related to JSRV. Systemic administration of the AAV6 vector encoding JSRV Env to mice produced numerous hepatocellular tumors, and some hemangiomas and hemangiosarcomas, showing that the Env protein can induce tumors in multiple cell types. CONCLUSION: Lung cancers induced by JSRV infection in sheep and by JSRV Env expression in mice have similar histologic features and are primarily characterized by adenomatous proliferation of peripheral lung epithelial cells. Thus it is unnecessary to invoke a role for insertional mutagenesis, gene activation, viral replication, or expression of other viral gene products in sheep lung tumorigenesis, although these processes may play a role in other clinically less important sequelae of JSRV infection such as metastasis observed with variable frequency in sheep