DNA probes for identifying chromosomes 5, 6, and 7 of Schistosoma mansoni

Schistosoma mansoni has a genome of 270 Mb contained on 8 pairs of chromosomes. C-banding has been a useful technique in identifying the 7 autosomal and sex chromosomes. However, even with C-banding, S. mansoni chromosomes 5, 6, and 7 are difficult to discriminate from each other, because of their small sizes, morphological similarity, and poor banding patterns. We have identified probes that specifically paint chromosomes 5, 6, and 7 of S. mansoni with the use of chromosome microdissection and the degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR). Exact chromosome identification is required for accurate chromosome mapping of genomic clones and genetic elements, which is an essential component of the schistosome genome project.

Vitamin K therapy for cortical bone fragility caused by reduced mechanical loading in a child with hemiplegia

Fractures frequently occur at cortical bone sites in children with cerebral palsy, but there is no established therapy. We previously found that treatment with vitamins D and K increased cortical bone mass in children with severe physical disability, and have hypothesized that vitamin K could play a significant role in pediatric cortical bones under conditions with reduced mechanical loading. In the present case report, we treated a right hemiplegic ambulant eight-year-old boy with oral vitamin K (15 mg per day) for eight months. Cortical bone geometries at mid-diaphyseal sites in bilateral tibiae were evaluated before and after the treatment. The cross-sectional total, bone and marrow areas of non-hemiplegic tibia increased by 8.8%, 7.4% and 12.0%, respectively, while those of hemiplegic tibia changed by 9.0%, 14.9% and -3.4%, respectively. As a result, the polar moment of inertia, an indicator of the resistance to torsion forces, increased by 13.0% in the non-hemiplegic tibia and by 63.7% in the hemiplegic tibia. Vitamin K may restrict cortical bone fragility, caused by reduced mechanical loading, through its actions at the endosteal bone marrow interface. Further studies are needed to confirm these findings and to clarify the mechanisms involved.

A case of an inflammatory myofibroblastic tumor in the lung which expressed TPM3-ALK gene fusion

We herein describe a 4-year-old boy who after being treated for pneumonia showed an abnormal shadow at the hilus of the right lung on chest X-rays with continued inflammatory findings in his laboratory data. CT and MR investigations suggested the existence of a neoplasm at that site. An open biopsy was thus performed for a definite diagnosis. The histological findings and the expression of TPM3-ALK fusion gene confirmed a diagnosis of an inflammatory myofibroblastic tumor. A right upper and middle lobectomy including the tumor was thus performed for a complete resection. In addition to the histological diagnosis, the detection of the tumor specific fusion gene provided objective evidence in making a diagnosis.

Renal leiomyoma: an immunohistochemical, ultrastructural and comparative genomic hybridization study

Renal leiomyoma is a rare neoplasm. We report such a case in a 57-year-old Japanese woman who was found to have a mass in the left kidney. The histological examination disclosed the proliferation of spindle cells showing a benign appearance. Entrapped tubular cells were observed in the peripheral area of the tumor. The immunohistochemical examination of spindle neoplastic cells showed a positive reaction for alpha smooth muscle actin, h-caldesmon, l-caldesmon, calponin, muscle actin, myosin and desmin. Additionally, the ultrastructural examination of the tumor showed membrane caveolae and myofilaments in the cytoplasm. This tumor was considered to show a differentiation into smooth muscle cells. The comparative genomic hybridization of the tumor detected the combined losses of chromosomes 4, 6, 12 and 14 which has not been previously described in renal tumors. Finally, the immunohistochemical panel of smooth muscle markers and ultrastructural and genetic study may be useful in diagnosing renal leiomyoma.

Impact of deletion of envelope-related genes of recombinant Sendai viruses on immune responses following pulmonary gene transfer of neonatal mice

We demonstrated previously that the additive-type recombinant Sendai virus (rSeV) is highly efficient for use in pulmonary gene transfer; however, rSeV exhibits inflammatory responses. To overcome this problem, we tested newly developed non-transmissible constructs, namely, temperature-sensitive F-deleted vector, rSeV/dF (ts-rSeV/dF) and a rSeV with all the envelope-related genes deleted (rSeV/dFdMdHN), for pulmonary gene transfer in neonatal mice, by assessing their toxicity and immune responses. The gene expression in the lungs of neonatal ICR mice peaked on day 2, then gradually decreased until almost disappearing at 14 days after infection in all constructs. Loss of body weight and mortality rate, however, were dramatically improved in mice treated with SeV/dFdMdHN (mortality=0%, n=41) and ts-rSeV/dF (24.2%, n=33) compared with additive rSeV (70.7%, n=58). Although the deletion of envelope-related genes of SeV had a small impact on the production of antibody and cytotoxic T-lymphocyte activity in both adults and neonates, a dramatic reduction was found in the events related to innate responses, including the production of proinflammatory cytokines, particularly in the case of neonates. These results indicate that pulmonary gene transfer using SeV/dFdMdHN warrants further investigation for its possible use in developing safer therapeutics for neonatal lung diseases, including cystic fibrosis.

Use of the AO hook-plate for treatment of unstable fractures of the distal clavicle

INTRODUCTION

We used a new internal fixative implant, the AO clavicle hook-plate, for treatment of unstable fractures of the distal clavicle. This study describes the operative procedure and the clinical results obtained, as well as discussion of the advantages and problems encountered.

PATIENTS AND METHODS

Fifteen consecutive patients with unstable fractures of the distal clavicle (Neer type II) were treated using AO clavicle hook-plates. The average age of patients was 47 years and there were 13 males and 2 females. The mean follow-up period was 15.5 months. Plain radiographs of clavicles were used to assess bony union. Functional recovery of the shoulder joint was assessed using the Constant-Murley scoring system.

RESULTS

All fractures eventually achieved solid bony union within 4 months after surgery. Thirteen patients (87%) showed hook migration into the acromion. Clinical results were excellent with a mean Constant-Murley score of 89 points at final follow-up.

CONCLUSION

AO clavicle hook-plates are useful fixative implants for unstable fractures of the distal clavicle. Static fixation was achieved and physiotherapy can be started immediately after surgery. Early removal of the implant is recommended however because hooks inserted under the acromion migrated into the bone in most cases.

Prenatal ultrasonographic and magnetic resonance imaging findings of congenital cloacal anomalies associated with meconium peritonitis

BACKGROUND/PURPOSE

Cloacal malformations are rare anomalies, occurring in females, and in which they demonstrate a single perineal orifice for urethra, vagina, and rectum. Prenatal ultrasonograms (US) of cloacal malformations sometimes show ascites, hydrocolpos, and hydronephrosis. We herein describe the characteristic prenatal US and magnetic resonance imaging (MRI) findings of the cloacal malformations associated with meconium peritonitis.

METHODS

The pre- and postnatal records of 11 newborn patients with cloacal malformations, treated in our hospital from 1988 to 2004, were reviewed. All fetuses underwent prenatal US by experienced obstetricians, whereas in addition, fetal MRI was performed in 1 patient.

RESULTS

The prenatal US and/or MRI findings showed fetal ascites, a multicystic pelvic mass, oligohydramnios, and bilateral hydronephrosis in 5 of 11 patients with cloacal malformations. In these 5 cases, postnatal examinations showed associated hydrocolpos, hydrometrocolpos, and bilateral hydronephrosis; furthermore, 4 of these 5 cases also showed meconium peritonitis at laparotomy.

CONCLUSIONS

The prenatal US and MRI findings, showing fetal ascites, multicystic pelvic mass, bilateral hydronephrosis, and oligohydraminios are highly suggestive of the cloacal malformations associated with meconium peritonitis.

Evaluation of a new caries detecting dye for primary and permanent carious dentin

OBJECTIVE

This study evaluated the clinical efficacy of a new caries detecting dye using a laser fluorescence device (DIAGNOdent).

METHOD

Primary and permanent teeth with dentin caries were stained with Caries Check (CC), containing 1% acid red in polypropylene glycol (MW=300) or Caries Detector (CD), containing 1% acid red in propylene glycol (MW=76). Primary-CC, primary-CD, permanent-CC and permanent-CD groups were prepared. In the CC groups, stained dentin was completely removed. In the CD groups, pink-stained dentin was retained according to the manufacturers' instructions. Cavities before and after caries removal were measured with the DIAGNOdent. Data were analyzed using ANOVA and Fisher's PLSD multiple comparison test at alpha=0.05. Regression analyses were performed between DIAGNOdent readings and scores obtained from the clinical parameters.

RESULTS

For all groups, there were no significant differences in the DIAGNOdent readings before treatment. The DIAGNOdent readings after caries removal were: primary-CC (16.0+/-17.6), primary-CD (9.6+/-5.2), permanent-CC (11.0+/-7.0) and permanent-CD (7.1+/-3.8). Significant differences were identified between the permanent-CC and primary-CD, and permanent-CC and permanent-CD subgroups but not for the primary subgroups. Correlation coefficients between DIAGNOdent readings and clinical parameters were low.

CONCLUSIONS

When dentin stained with Caries Check was completely removed, the DIAGNOdent readings were higher than those recorded when palely-stained pink dentin was retained with the Caries Detector, with significant difference observed for the permanent teeth. Caries Check may be used clinically to avoid excessive removal of caries-affected or sound dentin in permanent teeth but not in primary teeth.

Association between the HER2 expression and histological differentiation in Wilms tumor

Human epidermal growth factor receptors (HER) play a critical role in the branching morphogenesis of renal tubules. In the current study, we analyzed the expression of HER2 in Wilms tumor and assessed the role of this gene in the tumorgenesis of Wilms tumor. During the period from 1960 to 2005, 40 patients with Wilms tumor were treated in our department. Twenty-four of those patients (except those with clear cell sarcoma of the kidney and malignant rhabdoid tumor of the kidney) were collected and assessed. The histological component of each Wilms tumor was divided into three categories (epithelial, blastemal, and mesenchymal) and the extent of HER2 protein expression was analyzed immunohistochemically. The normal kidney tissue accompanied with 12 cases of Wilms tumor was also examined. In the normal kidney, HER2 showed a strong immunoreactivity in the cell membranes of the collecting tubules and in the endothelial cells. Of 24 cases, 15 cases showed an epithelial component, while 24 cases had a blastemal component and 21 cases had a mesenchymal component, respectively. Among the 15 specimens with epithelial cell differentiation, eight (53.3%) showed HER2 immunoreactive epithelial cells. HER2 immunoreactive blastemal cells were present in 11 (45.8%) of 24 specimens with blastemal cells. On the other hand, only 3 (14.3%) of 21 specimens containing mesenchymal cells showed HER2 immunoreactivity. These results suggest that the extent of HER2 expression is associated with epithelial differentiation in Wilms tumor. These histological findings may therefore help to explain the development of Wilms tumor from the standpoint of histological differentiation.

Effect of pulse duration on resonant heating of laser-irradiated argon and deuterium clusters

We study the effect of pulse duration on the heating of single van der Waals bound argon and deuterium clusters by a strong laser field using a two-dimensional (2D) electrostatic particle-in-cell (PIC) code in the range of laser-cluster parameters such that kinetic as well as hydrodynamic effects are active. Heating is dominated by a collisionless resonant absorption process that involves energetic electrons transiting through the cluster. A size-dependent intensity threshold defines the onset of this resonance [T. Taguchi, Physical Review Letters, 92, 20 (2004)]. It is seen that increasing the laser pulse duration lowers this intensity threshold and the energetic electrons take multiple laser periods to transit the cluster instead of one laser period. Our simulations also show that strong electron heating is accompanied by the generation of a high-energy peak in the ion energy distribution function. We also calculate the yield of thermonuclear fusion neutrons from exploding deuterium clusters using the PIC model with periodic boundary conditions that allows for the interaction of ions from neighboring clusters.

Spontaneous rupture of sacrococcygeal teratoma associated with acute fetal anemia

Sacrococcygeal teratoma (SCT) is the most common congenital tumor, with affected fetuses having a high risk of perinatal complications and death. We report a case of a fetus with an SCT that developed acute anemia due to spontaneous rupture of the tumor in utero. The fetus was referred at 25 weeks' gestation for evaluation of a large solid and cystic mass in the sacral region. There were no signs of hydrops or placentomegaly. At 33 weeks' gestation, loss of variability in the fetal heart rate pattern was recorded. Doppler ultrasonography showed increased middle cerebral artery peak systolic velocity, suggesting fetal anemia. Markedly bloody amniotic fluid, with 82% hemoglobin F, was observed on amniocentesis, suggesting rupture of the SCT with active fetal bleeding. An emergency Cesarean section was performed. At delivery, the tumor was bleeding actively and the neonatal hemoglobin concentration was 3.1 g/dL. There were no findings of hemorrhage or necrosis within the tumor. The neonate received a blood transfusion, and surgical resection of the tumor was carried out on the first day after delivery. Postoperatively, the baby did well. We suggest that fetal SCTs run the risk of inducing acute fetal anemia due to intrauterine hemorrhage of the tumor, a finding which could lead to an earlier and more appropriate management of this condition.

The effect of a valine-rich diet on intestinal adaptation to massive small bowel resection in the rat

BACKGROUND/PURPOSE

Recently, valine, which is one of the branched chain amino acids, has been reported to enhance liver regeneration after hepatectomy in the rat. The aim of this study was to investigate the effect of enteral valine supplementation on intestinal adaptation.

MATERIALS/METHODS

Seven-week-old male Lewis rats underwent a 90% small bowel resection. The rats were randomly divided into two groups: group V (valine-rich diet) and group S (standard rat chow), according to the diet. The rats were sacrificed at the operation day and on postoperative days (POD) 7, 14, 30, and 60. The metrics were body weight (BW), blood amino acids, urine organic acids, and morphology of the residual small intestine.

RESULTS

The BW and the intestinal wet weight, jejunal crypt depth, and proliferating cell nuclear antigen-positive cells in group V at POD 7 were significantly higher than those values in group S, while those in group V at POD 30 and 60 were smaller than those in group S. The urine methylmalonic acid (MMA) level in group V at POD 30 and 60 was much higher than in group S.

CONCLUSION

Valine enhanced intestinal adaptation after massive small bowel resection in the acute phase. However, the long-term supplementation disturbed intestinal adaptation, which might be due to the high production of MMA.

HIV-1 Vpr induces ATM-dependent cellular signal with enhanced homologous recombination

An ATM-dependent cellular signal, a DNA-damage response, has been shown to be involved during infection of human immunodeficiency virus type-1 (HIV-1), and a high incidence of malignant tumor development has been observed in HIV-1-positive patients. Vpr, an accessory gene product of HIV-1, delays the progression of the cell cycle at the G2/M phase, and ATR-Chk1-Wee-1, another DNA-damage signal, is a proposed cellular pathway responsible for the Vpr-induced cell cycle arrest. In this study, we present evidence that Vpr also activates ATM, and induces expression of gamma-H2AX and phosphorylation of Chk2. Strikingly, Vpr was found to stimulate the focus formation of Rad51 and BRCA1, which are involved in repair of DNA double-strand breaks (DSBs) by homologous recombination (HR), and biochemical analysis revealed that Vpr dissociates the interaction of p53 and Rad51 in the chromatin fraction, as observed under irradiation-induced DSBs. Vpr was consistently found to increase the rate of HR in the locus of I-SceI, a rare cutting-enzyme site that had been introduced into the genome. An increase of the HR rate enhanced by Vpr was attenuated by an ATM inhibitor, KU55933, suggesting that Vpr-induced DSBs activate ATM-dependent cellular signal that enhances the intracellular recombination potential. In context with a recent report that KU55933 attenuated the integration of HIV-1 into host genomes, we discuss the possible role of Vpr-induced DSBs in viral integration and also in HIV-1 associated malignancy.

Relationship Between Real-Time Monitoring of the Graft Motility and Mucosal Histology in Swine Intestinal Transplantation

We studied the correlation between the motility and the mucosal histology of the small bowel seeking to detect rejection in an early stage by real-time monitoring using a swine model. Intestinal transplantation (ITx) was performed orthotopically using FK506 immunosuppression. The distal about 20 cm segment of the allograft was exteriorized as a Thiry-Vella stoma for biopsies. Strain gauge (SG) force transducers were attached to the graft for real-time monitoring of graft motility. Pigs without ITx were used as controls (group 1). Rejection was classified into four groups by histologic findings: nonrejection (group 2), mild rejection (group 3), moderate rejection (group 4), and severe rejection (group 5). Migrating motor complex (MMC) phase III was analyzed for the following parameters: duration, amplitude, interval, motility index, velocity, and frequency of propagation. In group 2, all parameters were almost the same as those for group 1. In contrast, groups 4 and 5 showed most parameters significantly lower than those in group 1. In group 3, the contractility of the MMC was not significantly altered, but the frequency of the propagation was decreased significantly. In conclusion, graft motility detected by a real-time SG method correlated with the grade of mucosal histology. This method is useful to detect rejection at an early stage by examining the frequency of MMC propagation.

A case of IgG4-related autoimmune disease with multiple organ involvement

A 52-year-old male was admitted with autoimmune pancreatitis (AIP), showing mononuclear cell infiltration in both the pancreas and salivary glands with both normal sialography and anti-SS-A/SS-B antibodies. Although the AIP improved with glucocorticoid treatment, subsequent abdominal computed tomography (CT) revealed a nodular shadow in the bilateral kidneys, which was confirmed as interstitial nephritis by renal biopsy. The patient's serum immunoglobulin G4 (IgG4) level was 10 times higher than the upper limit of the normal range. IgG4-positive mononuclear cell infiltration was detected in the salivary gland, pancreas, and kidney. A new entity proposed as 'IgG4-related autoimmune disease' was considered.

Microkeratome assisted deep lamellar keratoprosthesis

AIMS

To establish a keratoprosthesis (Kpro) surgical technique that maintains an intact superficial corneal layer.

METHODS

A manual microkeratome (Moria LSK-1) was used to create a 130 mum flap of approximately 10 mm diameter in the right eye of Japanese white rabbits. The stoma beneath the flap area was dissected before the removal of a 5.0 mm stromal disc. A 5.0 mm collagen I immobilised poly(vinyl alcohol) (COL-PVA) disc was placed on the exposed posterior stroma close to Descemet's membrane. The flap was repositioned and fixed using 10-0 nylon sutures, which were removed 2 days following surgery. The corneas were followed clinically by slit lamp microscopy and photographs. Rabbits were sacrificed after 6 months, and the transplanted corneas were examined histologically by haematoxylin and eosin staining and immunohistochemistry against vimentin and alpha-smooth muscle actin (alpha-SMA).

RESULTS

The transplanted COL-PVA discs remained transparent throughout the study, with no complications related to the flap or overlying epithelium. The interface between COL-PVA and Descemet's membrane remained clear without signs of opacification caused by scarring or cellular deposition. Pathology revealed the intact COL-PVA polymer in the posterior stroma, with minimal cellular infiltration along the anterior and posterior interfaces. Immunohistology shows vimentin and alpha-SMA staining at levels comparable to lamellar keratoplasty control.

CONCLUSIONS

Microkeratome assisted deep lamellar keratoprosthesis may be a safe technique for the transplantation of artificial hydrogels for therapeutic purposes.

Purinergic receptor ligands stimulate pro-opiomelanocortin gene expression in AtT-20 pituitary corticotroph cells

Although recent studies have suggested that purinergic receptors are expressed in the anterior pituitary gland, their involvement in the regulation of pituitary hormone gene expression is not completely understood. In the present study, we examined the expression of purinergic receptors and the effects of purinergic receptor ligands on pro-opiomelanocortin (POMC) gene expression, in AtT20 mouse corticotroph cells. We identified the expression of most of the purinergic receptor subtypes (A1, A2, P2X1, 3-7, P2Y1, 2, 4) mRNAs, analysed by the reverse transcriptase-polymerase chain reaction. We also found that adenosine and ATP, two representative and endogenous agonists of A1-3 and P2X/P2Y receptors, respectively, stimulated the 5'-promoter activity of the POMC gene in a dose- and time-related manner. When these ligands were simultaneously used with corticotrophin-releasing hormone (CRH), effects that were more than additive were observed, suggesting an enhancing role of these compounds in CRH-mediated adrenocorticotrophic hormone (ACTH) synthesis. These ligands also stimulated the expression of transcription factors involved in the regulation of the POMC gene, but did not enhance ACTH secretion. Finally, the positive effect of adenosine as well as CRH was completely inhibited by the protein kinase A inhibitor H89, whereas that of ATP was not influenced, indicating that different intracellular signalling pathways mediate these effects. Altogether, our results suggest a stimulatory role for these purinergic receptor ligands in the regulation of POMC gene expression in corticotroph cells. Because adenosine and ATP are known to be produced within the pituitary gland, it is possible they may be acting in an autocrine/paracrine fashion.

Concurrent chemoradiotherapy with carboplatin and uracil–ftegafur in patients with stage two (T2 N0 M0) squamous cell carcinoma of the glottic larynx

This study aimed to evaluate the efficacy and toxicity of concurrent chemoradiotherapy as a primary treatment modality for larynx preservation in patients with stage two squamous cell carcinoma (SCC) of the glottic larynx. Between February 2000 and August 2003, a total of 20 patients received concurrent chemoradiotherapy. Carboplatin was given intravenously once a week during the period of radiotherapy. The weekly carboplatin dose was based on the area under the curve 1 to 1.25. Uracil–ftegafur (UFT) was given in a daily oral dose of 300 mg as tegafur. Radiotherapy was delivered five days a week using a once-daily fractionation of 2.0 Gray (Gy), to a total dose of 66–72 Gy. The three-year overall survival rate with larynx preservation was 100 per cent.

Concurrent chemoradiotherapy with carboplatin and UFT for stage two SCC of the glottic larynx was safe and effective in improving local control with larynx preservation.

Suppressive effects of dehydroepiandrosterone and the nuclear factor-kappaB inhibitor parthenolide on corticotroph tumor cell growth and function in vitro and in vivo

Dehydroepiandrosterone (DHEA) is believed to have an anti-tumor effect, as well as anti-inflammatory, antioxidant, and anti-aging effects. To clarify the possible inhibitory action of DHEA on pituitary tumor cells, we tested the effects of DHEA, alone or in combination with the nuclear factor-kappaB (NF-kappaB) inhibitor parthenolide (PRT), on AtT20 corticotroph cell growth and function both in vitro and in vivo. We found that, in vitro, DHEA and PRT had potent inhibitory effects on pro-opiomelanocortin and NF-kappaB-dependent gene expression. They also suppressed the transcription activity of survivin, a representative anti-apoptotic factor, and induced apoptosis in this cell line. Furthermore, using BALB/C nude mice with xenografts of AtT20 cells in vivo, we found that the combined administration of DHEA and PRT significantly attenuated tumor growth and survivin expression. The treatment also decreased the elevated plasma corticosterone levels and ameliorated the malnutrition induced by tumor growth. Altogether, these results suggested that combined treatments of DHEA and PRT potently inhibit the growth and function of corticotroph tumor cells both in vitro and in vivo. This effect may, at least partly, be caused by the suppressive effects of these compounds, such as survivin and other inhibitor of apoptosis proteins, on NF-kappaB-mediated gene transcription.

[Surgical treatment for stage IV lung cancer]

OBJECTIVE

To find out the optimal surgical indication in stage IV lung cancer patients, we evaluated them retrospectively.

METHODS & RESULTS

From 1975 to 2005, 62 patients without multiple metastases were operated at our hospital. The most common histological type was adenocarcinoma (67.7%). The metastatic lesions were lung (33.9%), brain (24.2%), liver, bone, adrenal gland and so on. The overall survival rate of stage IV lung cancer was 10.4% at 5-year. Five-year survival for patients with lung or brain metastasis who had no lymph node metastasis were significantly more superior than those with lymph node metastasis (p=0.0389, 0.0021). Four of 62 patients had 5-year survival. Two were lung and the others were brain and adrenal gland metastasis without lymph node metastasis.

CONCLUSION

Stage IV lung cancer with lung or brain or adrenal gland metastasis without lymph node metastasis should be resected.

Effects of lithium on endolymph homeostasis and experimentally induced endolymphatic hydrops

There is evidence to suggest that water homeostasis in the inner ear is regulated via the vasopressin (VP)-aquaporin 2 (AQP2) system in the same fashion as in the kidney. The VP-AQP2 system in the kidney is well known to be inhibited by lithium, resulting in polyuria due to a decrease in reabsorption of water in the collecting duct of the kidney. Therefore, lithium is also likely to inhibit the VP-AQP2 system in the inner ear, and consequently exert some influence on inner ear fluid homeostasis. In this study, we investigated the effects of lithium on AQP2 expression in the rat inner ear, and on the cochlear fluid volume in hydropic ears of guinea pigs. A quantitative PCR study revealed that lithium reduced AQP2 mRNA expression in the cochlea and endolymphatic sac. Lithium application also decreased the immunoreactivity of AQP2 in the cochlea and endolymphatic sac. In a morphological study, lithium intake significantly reduced endolymphatic hydrops dose-dependently. These results indicate that lithium acts on the VP-AQP2 system in the inner ear, consequently producing a dehydratic effect on the endolymphatic compartment.