The Acute Effects of Furosemide on Na-K-Cl Cotransporter-1, Fetuin-A and Pigment Epithelium-Derived Factor in the Guinea Pig Cochlea

Background

Furosemide is a loop diuretic used to treat edema; however, it also targets the Na-K-Cl cotransporter-1 (NKCC1) in the inner ear. In very high doses, furosemide abolishes the endocochlear potential (EP). The aim of the study was to gain a deeper understanding of the temporal course of the acute effects of furosemide in the inner ear, including the protein localization of Fetuin-A and PEDF in guinea pig cochleae.

Material and Method

Adult guinea pigs were given an intravenous injection of furosemide in a dose of 100 mg per kg of body weight. The cochleae were studied using immunohistochemistry in controls and at four intervals: 3 min, 30 min, 60 min and 120 min. Also, cochleae of untreated guinea pigs were tested for Fetuin-A and PEDF mRNA using RNAscope^® technology.

Results

At 3 min, NKCC1 staining was abolished in the type II fibrocytes in the spiral ligament, followed by a recovery period of up to 120 min. In the stria vascularis, the lowest staining intensity of NKCC1 presented after 30 min. The spiral ganglion showed a stable staining intensity for the full 120 min. Fetuin-A protein and mRNA were detected in the spiral ganglion type I neurons, inner and outer hair cells, pillar cells, Deiters cells and the stria vascularis. Furosemide induced an increased staining intensity of Fetuin-A at 120 min. PEDF protein and mRNA were found in the spiral ganglia type I neurons, the stria vascularis, and in type I and type II fibrocytes of the spiral ligament. PEDF protein staining intensity was high in the pillar cells in the organ of Corti. Furosemide induced an increased staining intensity of PEDF in type I neurons and pillar cells after 120 min.

Conclusion

The results indicate rapid furosemide-induced changes of NKCC1 in the type II fibrocytes. This could be part of the mechanism that causes reduction of the EP within minutes after high dose furosemide injection. Fetuin-A and PEDF are present in many cells of the cochlea and probably increase after furosemide exposure, possibly as an otoprotective response.

17β-Estradiol promotes angiogenesis of stria vascular in cochlea of C57BL/6J mice

It is widely accepted that the stria vascularis (SV) in cochlea plays a critical role in the generation of endocochlear potential (EP) and the secretion of the endolymph. 17β-estradiol (E2) is the most potent and abundant endogenous estrogen during the premenopausal period, thus, considered as the reference estrogen. This study aimd to investigate the protective effect of E2 by promoting the expression of vascular endothelial growth factor (VEGF) and thus promoting the vascular regeneration of the SV in elderly mice. After being treated with E2 either in vivo or in vitro, the hearing threshold changes of C57BL/6J elder mice continuously reduced, endothelial cell morphology improved, the number of endothelial cells (ECs) tubular nodes increased significantly, the ability of tubular formation enhanced significantly and the expression of VEGF increased. In vitro, cell model in conjunction with in vivo ovariectomized model was established to demonstrate for the first time that E2 promotes angiogenesis by promoting the secretion of VEGF through the phosphatidylinositol 3-kinase (PI3K)/AKT pathway (PI3K/AKT). In conclusion, E2 demonstrated potent angiogenesis properties with significant protection against Age-Related Hearing Loss (ARHL), which provides a new idea for the improvement of ARHL.

Metastases to nasal cavity and paranasal sinuses

The sinonasal cavities are rare locations for metastases. Metastases to these locations are usually solitary and produce similar symptoms to those of a primary sinonasal tumor. Nasal obstruction and epistaxis are the most frequent symptoms. The maxillary sinus is most frequently involved. The most common primary tumor sites to spread to this region originate in the kidney, breast, thyroid, and prostate, although any malignancy could potentially lead to a metastasis to the paranasal sinuses. The patient's prognosis is usually poor because of the fact that the sinonasal metastasis is usually associated with widespread disseminated disease. In the majority of patients, palliative therapy is the only possible treatment option. Nevertheless, whenever possible, surgical excision either alone or combined with radiotherapy may be useful for palliation of symptoms and, rarely, to achieve prolonged survival. This review considers the most interesting cases reported in the literature that presents metastases to the sinonasal cavities. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1847-1854, 2016.

Deafness induction in mice

HYPOTHESIS

How to induce most efficiently severe sensorineural hearing loss in mice using a single coadministration of an aminoglycoside antibiotic and a loop diuretic?

BACKGROUND

The coadministration of aminoglycosides and a loop diuretic has been widely used to induce hair cell and spiral ganglion cell loss in guinea pigs. However, the development of new treatment strategies against sensorineural hearing loss, such as tissue engineering techniques, requires the use of mouse models. Previous attempts to induce hearing loss in mice have rendered inconsistent results because of resistance to aminoglycoside-induced ototoxicity. Especially inner hair cells seem to be resistant to aminoglycoside-induced ototoxicity.

METHODS

In the present study, we aim to optimize hearing loss in mice, using a single high-dose kanamycin (700 and 1,000 mg/kg) injection followed by a furosemide (100 mg/kg) administration. Although previous studies used intraperitoneal furosemide injections 30 minutes after kanamycin administration, we used intravenous furosemide injections administered within 5 minutes after kanamycin treatment.

RESULTS

Auditory brain stem responses illustrated severe threshold shifts, and histologic analysis showed marked outer hair cell destruction as well as spiral ganglion cell loss. The present protocol results in more severe inner hair cell loss when compared with the results of previous researches.

CONCLUSION

We conclude that severe sensorineural hearing loss can be induced in mice. Moreover, we found that this mouse model can be augmented via the use of rapid intravenous furosemide administrations to maximize inner hair cell loss.

Metastatic tumors to the oral and maxillofacial region: a retrospective study of 19 cases in West China and review of the Chinese and English literature

PURPOSE

The aim of this article was to obtain an overview of metastatic tumors to the oral and maxillofacial (OMF) region, especially the differences in the constituent ratios of primary cancers between the United States and China.

PATIENTS AND METHODS

Clinical findings of 19 cases encountered in West China Hospital of Stomatology were summarized and the English and Chinese literature were reviewed and analyzed. The main clinical features of OMF metastases were summarized, with an emphasis on primary cancers' constituents.

RESULTS

The lung, breast, kidney, liver, and prostate were the top 5 common primary sites of cancer. However, there was a significant difference in the primary cancers' constituents between United States and China (P < .001). The breast, kidney, prostate cancers, and melanoma of skin were more frequent primary cancers in United States than in China, whereas that of the lung, thyroid, liver, esophagus, and the stomach were more common in China than in United States. The proportions of the OMF metastatic lesions originating in the lung, kidney, liver, thyroid, and esophagus in all OMF metastatic tumors were higher than the corresponding primary cancers' prevalent proportions.

CONCLUSIONS

The frequency of developing OMF metastasis is not always consistent with primary cancers' prevalence, which suggests that different cancers have different potentiality to develop OMF metastasis. Cancers of the kidney, liver, lung, thyroid, and esophagus were more likely to spread to the OMF region. In general screening of primary cancer, it would be helpful to take into account the metastatic potentiality of different cancers and primary cancers' prevalence in different countries in the case of occult primary.

[Frontal ethmoid metastases of prostatic carcinoma. Report of one case and review of the literature]

Prostatic metastases in the nose and paranasal sinuses are rare. Less than 100 cases have been reported in the literature. Kidney are the commonest site of primary tumour, followed by lung and breast. Only 10 cases have previously been reported in the world literature. Prostatic metastases have been mainly reported in the sphenoid sinus. This paper reports one case of metastases of prostatic carcinoma in the fronto-ethmoid sinus in a 72 years old male. The clinical picture includes acute fronto-ethmoid right sinusitis, severe exophthalmos and chemosis. The CT scan showed extensive soft tissue filling the maxillary, ethmoid cells, sphenoid and frontal right sinuses, with subdural abscess. Biopsies from the fronto-ethmoid mass showed infiltration by adenocarcinoma with positive immunostaining for prostatic specific antigen. We also review the literature about metastases involving the nose and paranasal sinuses.

Metastatic thyroid carcinoma: an unusual presentation

A case is described in which the presentation of symmetrical thyroid lesions combined with their unusual site and histological appearance served initially to mask the underlying thyroid neoplasm.