Botulinum Neurotoxins and Cancer-A Review of the Literature

Botulinum neurotoxins (BoNT) possess an analgesic effect through several mechanisms including an inhibition of acetylcholine release from the neuromuscular junction as well as an inhibition of specific pain transmitters and mediators. Animal studies have shown that a peripheral injection of BoNTs impairs the release of major pain transmitters such as substance P, calcitonin gene related peptide (CGRP) and glutamate from peripheral nerve endings as well as peripheral and central neurons (dorsal root ganglia and spinal cord). These effects lead to pain relief via the reduction of peripheral and central sensitization both of which reflect important mechanisms of pain chronicity. This review provides updated information about the effect of botulinum toxin injection on local pain caused by cancer, painful muscle spasms from a remote cancer, and pain at the site of cancer surgery and radiation. The data from the literature suggests that the local injection of BoNTs improves muscle spasms caused by cancerous mass lesions and alleviates the post-operative neuropathic pain at the site of surgery and radiation. It also helps repair the parotid damage (fistula, sialocele) caused by facial surgery and radiation and improves post-parotidectomy gustatory hyperhidrosis. The limited literature that suggests adding botulinum toxins to cell culture slows/halts the growth of certain cancer cells is also reviewed and discussed.

Relatively high rates of G:C → A:T transitions at CpG sites were observed in certain epithelial tissues including pancreas and submaxillary gland of adult big blue® mice

With few exceptions, spontaneous mutation frequency and pattern are similar across tissue types and relatively constant in young to middle adulthood in wild type mice. Underrepresented in surveys of spontaneous mutations across murine tissues is the diversity of epithelial tissues. For the first time, spontaneous mutations were detected in pancreas and submaxillary gland and compared with kidney, lung, and male germ cells from five adult male Big Blue® mice. Mutation load was assessed quantitatively through measurement of mutant and mutation frequency and qualitatively through identification of mutations and characterization of recurrent mutations, multiple mutations, mutation pattern, and mutation spectrum. A total of 9.6 million plaque forming units were screened, 226 mutants were collected, and 196 independent mutations were identified. Four novel mutations were discovered. Spontaneous mutation frequency was low in pancreas and high in the submaxillary gland. The submaxillary gland had multiple recurrent mutations in each of the mice and one mutant had two independent mutations. Mutation patterns for epithelial tissues differed from that observed in male germ cells with a striking bias for G:C to A:T transitions at CpG sites. A comprehensive review of lacI spontaneous mutation patterns in young adult mice and rats identified additional examples of this mutational bias. An overarching observation about spontaneous mutation frequency in adult tissues of the mouse remains one of stability. A repeated observation in certain epithelial tissues is a higher rate of G:C to A:T transitions at CpG sites and the underlying mechanisms for this bias are not known.

Supramandibular canal portion superior to the fossa of the submaxillary gland: a tomographic evaluation of the cross-sectional dimension in the molar region

PURPOSE

Within the fossa of the submaxillary gland (FSG), there is a portion superior to the mandibular canal (SMCP) that can affect implant placement. Our study evaluated this specific portion's prevalence and its average dimensional difference between the first and the second molar regions in a dental implant population.

MATERIALS AND METHODS

From 112 patients' mandibular cone beam computerized tomography scans, the SMCPs of the FSG's horizontal and vertical dimensions in the first and second molar positions on both sides were digitally measured.

RESULTS

The SMCP of the FSG is larger in the second molar region than in the first molar region in >90% of cases. Average differences were 2.3 mm horizontally and 2.7 mm vertically. Gender difference and intraindividual's left/right variation were both clinically less significant in magnitude than the difference between the molar regions. Taking the 2-mm safety margin above the mandibular canal into consideration, the SMCP of the FSG remained high in prevalence.

CONCLUSIONS

The SMCP of the FSG may complicate implant placement more in the second molar region than in the first. Implant planning in the posterior mandibular molar regions should include a SMCP of the FSG evaluation using computer tomography especially in the second molar region.

Muscarinic Receptor Binding and Plasma Drug Concentration after the Oral Administration of Propiverine in Mice

OBJECTIVES

The current study was undertaken to characterize the binding of propiverine to muscarinic receptors in mouse tissues by measuring plasma concentrations of the drug and its metabolite.

METHODS

At 0.5-24 h after the oral administration of propiverine at pharmacologically relevant doses, muscarinic receptors in tissue homogenates were measured by a radioligand binding assay using [N-methyl- (3) H]scopolamine (NMS), along with the drug's concentration in plasma by the liquid chromatography-tandem mass spectrometric method.

RESULTS

In the in vitro experiments, propiverine and its metabolite 1-methy-4-piperidyl benzilate N-oxide competed with [(3) H]NMS for binding sites in the bladder, submaxillary gland and heart of mice in a concentration-dependent manner. After the oral administration of propiverine, dose- and time-dependent increases in the dissociation constant for specific [(3) H]NMS binding were observed in the bladder and other tissues of mice, indicating that orally administered propiverine and/or its metabolite undergo significant binding to muscarinic receptors in mouse tissues. A longer-lasting binding of muscarinic receptor was seen in the bladder than in the submaxillary gland at relatively low doses of propiverine. Furthermore, the decrease in maximal number of binding sites values for [(3) H]NMS binding was more remarkable in the bladder than submaxillary gland of propiverine treated mice. There was a dose-dependent rise in the plasma concentrations of propiverine and 1-methy-4-piperidyl benzilate N-oxide in mice after the oral administration of propiverine.

CONCLUSION

The oral administration of propiverine exerts a more prominent and longer-lasting effect in the bladder than in the submaxillary gland of mice. The N-oxide metabolite may contribute significantly to the blockade of muscarinic receptors caused by oral propiverine.

Characterization of a coronavirus isolated from rats with sialoadenitis

A causative agent, provisionally designated as CARS, was isolated from the enlarged submaxillary gland of rat which was characterized as a sialoadenitis, using mouse-derived Balb/c3T3 clone A31 (3T3) cell culture. The virus could be propagated in 3T3 cell culture where it produced multinucleated giant cells and formed clear plaques. It was identified as a member of the coronavirus group from the following results: RNA content was suggested by the lack of the effect of cytosine arabinoside, the infectivity was sensitive to lipid solvents and inactivated at 56 degrees C for 5 minutes, the viral particle showed typical coronavirus morphology which was approximately 100 nm in diameter. Serologically, although CARS and sialodacryoadenitis virus (SDAV) actually belonged to the rat-coronavirus group, some antigenic variations existed between these two agents in the results of both neutralization and complement-fixation tests using monovalent antisera. When inoculated intranasally into susceptible rats, CARS caused clinically and histologically overt sialoadenitis as observed in the natural outbreak, and retained its virulence for rats in several passages of mouse brain and even when cell culture was used, while rats which were inoculated with SDAV were asymptomatic.

Evidence for pro-beta-nerve growth factor, a biosynthetic precursor to beta-nerve growth factor

The biosynthesis of beta-nerve growth factor (betaNGF) was studied in mouse submaxillary glands incubated with L-[(35)S]cystine. betaNGF was isolated from tissue extracts by the addition of antiserum against betaNGF and the washed immunoprecipitates were analyzed by sodium dodecyl sulfate gel electrophoresis. With short labeling periods (10 and 25 min) there is a major labeled species with an apparent molecular weight of 22,000 and a smaller peak comigrating with purified betaNGF chains (13,260). As time proceeds, the radioactivity in the 22,000 molecular weight peak plateaus, while the label in betaNGF continues to increase, until by 4 hr it greatly exceeds the radioactivity of the 22,000 molecular weight species. When glands incubated for 10 min are transferred to medium containing a large excess of unlabeled L-cystine, the 22,000 molecular weight peak gradually declines, and there is a corresponding increase in radioactivity at the betaNGF position. The 22,000 molecular weight species isolated from sodium dodecyl sulfate gels possesses all the cystine-containing peptides of betaNGF, and possibly two additional ones. When immunoprecipitates from submaxillary glands labeled for 25 min are incubated with the gamma subunit (a specific arginyl-esteropeptidase associated with betaNGF in the 7S NGF complex), the radioactivity in the 22,000 molecular weight species is converted to the betaNGF position. The results suggest that the 22,000 molecular weight species is a biosynthetic precursor to betaNGF, and that the gamma subunit may function as a specific protease in the processing event.