A Comprehensive Assessment of Tear-Film-Oriented Diagnosis (TFOD) in a Dacryoadenectomy Dry Eye Model.

Tear film instability is a major cause of dry eye disease. In order to treat patients with short tear film breakup time (TBUT)-type dry eye, the development of tear film stabilizing agents is essential. However, the lack of an appropriate animal model of tear film instability has made drug development difficult. Although rabbit dry eye models have been reported in the past, there are only a few reports that focus on tear film instability. Herein, we assessed the tear film stability of a rabbit dry eye model induced by dacryoadenectomy. A clinical evaluation of the ocular surface, interferometry, and histological assessments of the cornea and conjunctiva were performed. Following the removal of the lacrimal glands, TBUT was shortened significantly, with dimple and random breakup patterns prominently observed. Furthermore, the blink rate in this model increased after dacryoadenectomy, suggesting that this model partially captured the phenotypes of human short TBUT-type dry eye and may be useful as an animal model for investigating potential drug candidates.

Factors Affecting Postoperative Spinal Epidural Hematoma and the Optimal Order of Vertebral Body Decompression in Multivertebral Microendoscopic Laminectomy.

Purpose Symptomatic postoperative spinal epidural hematoma (POSEH) is a complication of spine surgery that occurs infrequently but may cause ongoing serious neurological damage. Due to the narrow entry portal, the risk of hematoma is increased after microendoscopic laminectomy (MEL) compared with conventional open surgery, and the risk might be even higher for multivertebral MEL (m-MEL). The purpose of this study was to clarify the factors affecting the development of POSEH after m-MEL and identify the optimal order for the decompression of vertebral bodies. Methods A total of 313 patients who underwent m-MEL from 2016 to 2020 were retrospectively assessed. The cohort comprised 238 patients who underwent two-level MEL, 67 who underwent three-level MEL, and eight who underwent four-level MEL. Symptomatic POSEH was defined as the presence of an epidural hematoma at the surgical site on MRI with symptoms such as lower extremity pain or muscle weakness. We elucidated the incidence of POSEH at each vertebral level and investigated the relationship between POSEH and possible risk factors such as clinical and operative variables. Results There were 41 patients in the POSEH group and 272 patients in the non-POSEH group. Seven patients in the POSEH group underwent reoperation. The occurrence of POSEH was related to the number of decompressed vertebral bodies. Patients who underwent L2/3 and L3/4 decompression at the end of the procedure also showed a higher incidence of POSEH at the surgical level. Conclusion In patients undergoing m-MEL, treatment of the upper lumbar vertebrae at the end of decompression surgery might be a risk factor for symptomatic POSEH. The incidence of POSEH was particularly increased at L2/3, suggesting that L2/3 decompression should not be performed at last and that careful hemostasis should be applied.

Gauze blotting technique: a novel method to identify parathyroid glands during thyroid surgery without tissue damage.

Hypoparathyroidism is a major complication of thyroid surgery. To avoid this complication, visual identification of the parathyroid glands is essential. However, its effectiveness depends heavily on the surgeon's expertise. Here, we describe a novel method, the gauze blotting technique, to immunochemically identify the parathyroid glands during thyroid surgery. Twenty-three patients who underwent thyroid lobectomy were enrolled in this study; 16 and 7 had benign and malignant thyroid diseases, respectively. After visually identifying candidate nodules for the parathyroid gland, a piece of dry gauze (5 mm × 10 mm) was applied to each tissue until it was moistened by exudates from the tissue. Pieces of gauze were also applied to the thyroid gland and adipose tissue located away from the candidate nodules. The gauze was immersed in saline, and the intact PTH (i-PTH) level of the supernatant was measured. The median PTH level for the parathyroid glands was 1,060 pg/mL, which was significantly higher than that for the thyroid gland (34 pg/mL) and adipose tissue (28 pg/mL) (p < 0.001). The cut-off value to distinguish the parathyroid gland from other tissues was 68 pg/mL with a positive predictive value, negative predictive value, sensitivity, and specificity of 84.6%, 88.8%, 86.8%, and 86.7%, respectively. A value ≥250 pg/mL yielded a 100% positive predictive value. Our novel gauze blotting technique can identify the parathyroid glands without damaging tissues during thyroid surgery.

Efficacy of Nerve Root Block for the Treatment of Lumbar Spinal Canal Stenosis in Adults Older Than 80 Years of Age.

BACKGROUND: Patients with advanced lumbar spinal canal stenosis (LCS) often prefer non-operative treatment owing to decreased physiological function and comorbidities. Although the therapeutic value of selective nerve root block (SNRB) for LCS is confirmed, there are few reports of its effectiveness in the elderly. We investigated the efficacy of SNRB for LCS in patients over 80 years of age. METHODS:  The subjects were 112 patients aged over 80 years (mean age: 84 years; 45 men and 67 women ) with medication-resistant LCS without cauda equina syndrome who underwent SNRB. Cases with acute-onset lumbar disc herniation were excluded. We retrospectively investigated and compared the presence or absence of surgery, effect of SNRB, number of procedures, duration of disease, and magnetic resonance imaging findings. Patients who could avoid the surgery by SNRB were defined as the effective group. Patients whose symptoms were not relieved by SNRB and who underwent surgery and those whose symptoms were not relieved but who continued conservative treatment were defined as the ineffective group. A total of one to seven SNRBs were performed in both groups, and the same spine surgeon performed the entire procedure from SNRB to surgery. RESULTS:  There were 86 nonoperative patients (69 effective cases) and 26 operative patients; the overall rate of effectiveness was 61% (69/112 patients). The area of the spinal canal at the responsible level was 108.63 mm2 in the effective group compared with 77.06 mm2 in the ineffective group. This was significantly narrower in the ineffective group (p=0.0094). There was no significant difference in the duration of illness, number of blocks, or hernia complication rate between the groups. No patient experienced severe neuralgia that may have been caused by neuropathy during SNRB. DISCUSSION: Our outcome showed that more than 60% of older patients with LCS showed symptomatic improvement with SNRB. SNRB can be performed relatively safely in the elderly and appears to be a favorable treatment option for older patients with various risks, such as poor general condition. CONCLUSIONS: Multiple sessions of SNRB may provide older patients with symptomatic improvement and may be an option for treatment.

Observational management of papillary microcarcinoma appearing in the remnant thyroid after hemithyroidectomy.

Active surveillance for papillary thyroid microcarcinomas (PTMCs) initiated in Japan is becoming adopted worldwide as a management option. However, it remains unclear how to manage newly appearing PTMCs in the remnant thyroid after hemithyroidectomy. We investigated the outcomes of similar observational management (OM) for PTMCs appearing in the remnant thyroid after hemithyroidectomy for papillary thyroid carcinoma (PTC) and benign thyroid nodules. Eighty-three patients were newly diagnosed with PTMC in the remnant thyroid between January 1998 and March 2017. Of these, 42 patients underwent OM with >3 times ultrasound examinations. Their initial diagnoses were PTC (initially malignant group) in 37 patients and benign nodule (initially benign group) in 5 patients. We calculated the tumor volume doubling rate (TV-DR) during OM for each PTMC. The TV-DR (/year) was <-0.1, -0.1-0.1, 0.1-0.5, and >0.5 in 12, 19, 5, and 6 patients, respectively. The TV-DRs in both groups did not statistically differ, but six patients (16%) in the initially malignant group showed moderate growth (TV-DR >0.5/year). They underwent conversion surgery and none of them had further recurrence. The remaining 36 patients retained OM without disease progression. The TV-DR in the initially malignant group was not significantly associated with patients' backgrounds or their initial clinicopathological features. None of the patients in this study showed distant metastases/recurrences or died of thyroid carcinoma. Although a portion of PTMCs appearing after hemithyroidectomy for thyroid malignancy are moderately progressive, OM may be acceptable as a management option for PTMCs appearing in the remnant thyroid after hemithyroidectomy.

Poorly Differentiated Thyroid Carcinoma Coexisting with Graves' Disease Involving T3 Thyrotoxicosis due to Increased D1 and D2 Activities.

Background: Poorly differentiated thyroid carcinoma is rare and patients are typically euthyroid. We report a novel rare case of poorly differentiated thyroid carcinoma with triiodothyronine (T3) thyrotoxicosis. Patient's Findings: A 77-year-old man presented to Kuma Hospital due to a neck tumor. A thyroid ultrasonography revealed a 220-mL mass in the right lobe. Laboratory data showed low serum thyrotropin (TSH), low free thyroxine (fT4), and high free T3 (fT3) levels. Anti-TSH receptor antibodies and thyroid-stimulating antibodies were positive. 131I scintigraphy showed diffuse uptake only in the left thyroid lobe. The patient underwent a total thyroidectomy and histological examination identified as poorly differentiated thyroid carcinoma. He was diagnosed with poorly differentiated thyroid carcinoma coexisting with Graves' disease. The tumor showed elevated type 1 iodothyronine deiodinases (D1) and type 2 iodothyronine deiodinases (D2) activities compared with that of the left thyroid lobe. Summary and Conclusions: Increased D1 and D2 activities in poorly differentiated carcinoma resulted in T3 toxicosis with a high serum fT3/fT4 ratio.

Evaluation of the diagnostic utility of the aminotransferase/lactate dehydrogenase ratio for the suspension of tissue specimens during thyroid surgery for the identification of parathyroid tissue.

Identification of the parathyroid glands during surgery is crucial for preventing postoperative hypoparathyroidism. Kikumori et al. reported that the aspartate aminotransferase (AST)/lactate dehydrogenase (LDH) ratio for the saline suspension of a suspicious tissue can differentiate parathyroid tissue from other tissues. The aim of this study was to evaluate the utility of this method and investigate the appropriate time for measurement. We obtained 465 tissue specimens during thyroidectomy of 102 patients with papillary thyroid carcinoma (PTC), and 422 specimens (129 parathyroid, 92 PTC, and 201 other tissues) with measurable AST and LDH were analyzed. Small pieces of the tissues were immersed in saline and sent for measurement of AST and LDH. The assay was performed immediately after thyroidectomy for 245 specimens (the same-day group) and during the next morning for the remaining 177 specimens (the next-day group). The accuracy of diagnosing parathyroid tissue was significantly better in the same-day group than in the next-day group. A cut-off value of 0.18 gave the best diagnostic precision, with an area under the receiver operating characteristic curve of 0.95 and 88.7% sensitivity and specificity in the same-day group. When the cut-off value was set to 0.20, the specificity for excluding carcinomatous tissues was 100%. When measured on the day of the surgery, the AST/LDH ratio for the saline suspension of the surgical specimens is useful for discriminating parathyroid tissues from other tissues. This method can be utilized at most hospitals where intraoperative frozen sections or rapid parathyroid hormone assays are not available.

Marked Decrease Over Time in Conversion Surgery After Active Surveillance of Low-Risk Papillary Thyroid Microcarcinoma.

Background: Active surveillance for low-risk papillary microcarcinoma (PMC) of the thyroid is an accepted and safe management strategy. However, some patients undergo conversion surgery after the initiation of active surveillance for various reasons. We investigated the reasons for conversion surgery and whether and how they changed over time. Methods: We enrolled 2288 patients with PMC who underwent active surveillance. Of these, 162 (7.1%) underwent conversion surgery >12 months after initiating active surveillance due to disease progression (57 patients), patient preference (43 patients), physician preference (31 patients), other associated thyroid or parathyroid diseases (24 patients), and other reasons (7 patients). We analyzed cumulative conversion rates not only in the whole cohort but also in the first three major subsets based on the reasons for surgery. We also divided our whole cohort into two groups based on the period of active surveillance commencement: the first-half group (February 2005-November 2011; 561 patients) and the second-half group (December 2011-June 2017; 1727 patients). Results: The criteria for PMC progression did not differ between the first- and second-half groups. The proportion of female patients in the physician preference group was significantly higher than that in the disease progression and the patient preference groups. Tumor size at surgery was larger, and tumor volume-doubling rate was higher in the disease progression group than in the other two groups. Patients in the second-half group were significantly less likely to undergo conversion surgery than those in the first-half group. Furthermore, conversion surgery rates in the second-half group were significantly lower than those in the first-half group in the patient preference, physician preference, and disease progression groups. Conclusions: Patients with PMC in the second-half group were significantly less likely to undergo conversion surgery than those in the first-half group regardless of the reason. This is probably because data accumulation of favorable outcomes with active surveillance significantly contributed to physicians' confidence and patients' trust and understanding of this disease.

Subset analysis of the Japanese risk classification guidelines for papillary thyroid carcinoma.

Guidelines published by the Japan Association of Endocrine Surgeons (JAES)/Japanese Society of Thyroid Surgery (JSTS) for patients with papillary thyroid carcinoma describe four risk classes (very low-, low-, intermediate- and high-risk) for deciding on therapeutic strategies. Here, we investigate cause-specific survival (CSS) of high- and intermediate-risk patients, taking their age into consideration. CSS of intermediate-risk patients ≥55 years was poorer than that of those <55 years (p < 0.0001) (20-year CSS rates, 96.9% vs. 98.7%). CSS of intermediate-risk patients <55 years was excellent but still poorer (p = 0.0152) than that of low- or very low-risk patients (20-year CSS rates, 100%). CSS of high-risk patients <55 years (20-year CSS rates, 96.0%) was similar (p = 0.7412) to that of intermediate-risk patients ≥55 years, while high-risk patients ≥55 years (20-year CSS rates, 80.6%) showed much poorer prognosis (p < 0.0001) than the others. In high-risk patients <55 years, distant metastasis (M1), extrathyroid extension (Ex), node metastasis ≥3 cm, and extranodal tumor extension, and in those ≥55 years, M1, Ex, and tumor size >4 cm were regarded as prognostic factors on multivariate analysis. We therefore conclude that 1) prognosis of high-risk patients ≥55 years should be carefully treated because of significantly poor prognosis, 2) prognostic factors of high-risk patients vary according to patient age, and 3) overtreatment of intermediate-risk patients and young high-risk patients should be avoided; however, appropriate treatment strategies need to be established, considering that their prognoses are excellent, but still poorer than low- or very low-risk patients.

JNK-mediated Slit-Robo signaling facilitates epithelial wound repair by extruding dying cells.

Multicellular organisms repair injured epithelium by evolutionarily conserved biological processes including activation of c-Jun N-terminal kinase (JNK) signaling. Here, we show in Drosophila imaginal epithelium that physical injury leads to the emergence of dying cells, which are extruded from the wounded tissue by JNK-induced Slit-Roundabout2 (Robo2) repulsive signaling. Reducing Slit-Robo2 signaling in the wounded tissue suppresses extrusion of dying cells and generates aberrant cells with highly upregulated growth factors Wingless (Wg) and Decapentaplegic (Dpp). The inappropriately elevated Wg and Dpp impairs wound repair, as halving one of these growth factor genes cancelled wound healing defects caused by Slit-Robo2 downregulation. Our data suggest that JNK-mediated Slit-Robo2 signaling contributes to epithelial wound repair by promoting extrusion of dying cells from the wounded tissue, which facilitates transient and appropriate induction of growth factors for proper wound healing.

ROR1-CAVIN3 interaction required for caveolae-dependent endocytosis and pro-survival signaling in lung adenocarcinoma.

The receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a transcriptional target of the lineage-survival oncogene NKX2-1/TTF-1 in lung adenocarcinomas. In addition to its kinase-dependent role, ROR1 functions as a scaffold protein to facilitate interaction between caveolin-1 (CAV1) and CAVIN1, and consequently maintains caveolae formation, which in turn sustains pro-survival signaling toward AKT from multiple receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR), MET (proto-oncogene, receptor tyrosine kinase), and IGF-IR (insulin-like growth factor receptor 1). Therefore, ROR1 is an attractive target for overcoming EGFR-TKI resistance due to various mechanisms such as EGFR T790M double mutation and bypass signaling from other RTKs. Here, we report that ROR1 possesses a novel scaffold function indispensable for efficient caveolae-dependent endocytosis. CAVIN3 was found to bind with ROR1 at a site distinct from sites for CAV1 and CAVIN1, a novel function required for proper CAVIN3 subcellular localization and caveolae-dependent endocytosis, but not caveolae formation itself. Furthermore, evidence of a mechanistic link between ROR1-CAVIN3 interaction and consequential caveolae trafficking, which was found to utilize a binding site distinct from those for ROR1 interactions with CAV1 and CAVIN1, with RTK-mediated pro-survival signaling towards AKT in early endosomes in lung adenocarcinoma cells was also obtained. The present findings warrant future study to enable development of novel therapeutic strategies for inhibiting the multifaceted scaffold functions of ROR1 in order to reduce the intolerable death toll from this devastating cancer.

Natural history of papillary thyroid microcarcinoma: Kinetic analyses on tumor volume during active surveillance and before presentation.

BACKGROUND: We report on the growth of papillary microcarcinoma during active surveillance and before clinical presentation. METHODS: We conducted a retrospective study of 169 patients with papillary microcarcinoma who were enrolled in active surveillance at our hospital between 2000 and 2004. Patients were followed for a median of 10.1 years using serial ultrasonography (median, 12 examinations), used to calculate the tumor doubling time. To contextualize tumor growth rates during active surveillance, we calculated the hypothetical tumor doubling time before clinical presentation. To resolve the limitations in tumor doubling time, tumor doubling rates were inversely transformed into doubling rates. RESULTS: The doubling rates (per year) during active surveillance (median: 0.0) were >0.5, 0.1 to 0.5, -0.1 to 0.1, and <-0.1 in 5, 38, 97, and 29 cases, respectively. The proportions of tumors with rather rapid growth, slow growth, stable, and a decrease in size were 3%, 22%, 57%, and 17%, respectively. CONCLUSION: Tumor growth of papillary microcarcinomas varies from rather rapid growth to a decrease in size during active surveillance.

Calcitonin measurement in fine-needle aspirate washout fluid by electrochemiluminescence immunoassay for thyroid tumors.

PURPOSE: For the differential diagnosis of medullary thyroid carcinoma (MTC) on thyroid nodules, ultrasound-guided fine-needle aspiration cytology is a useful and safe procedure, but its diagnostic accuracy is not high enough. As an ancillary method to accurately diagnose MTC, the calcitonin in fine-needle aspirate washout fluid (FNA-Ct) is used. However, no data are available about cut-off values of FNA-Ct using the currently available electrochemiluminescence immunoassay (ECLIA). METHODS: We investigated 180 thyroid nodules in 141 patients. After smearing, the syringe and needle used for the FNA were rinsed with normal saline (0.5 mL). The calcitonin in the washout was measured by ECLIA. RESULTS: The FNA-Ct in the non-MTC nodules of MTC patients, non-MTC nodules of non-MTC patients, and MTC nodules were 10.6-2100 pg/mL (median 24.6 pg/mL), < 0.5-21.0 pg/mL (median < 0.5 pg/mL), and 94.9-4,070,000 pg/mL (median 177,000 pg/mL), respectively. A receiver operating characteristic analysis of the MTC nodules and the non-MTC nodules of the non-MTC patients indicated that the cut-off value was 21.0 pg/mL, leading to 100% sensitivity and 100% specificity. CONCLUSIONS: This is the first study to determine the cut-off value of FNA-Ct with an ECLIA, and we propose that the optimal cut-off value is 21.0 pg/mL.

Prognostic value of the 8th edition of the tumor-node-metastasis classification for patients with papillary thyroid carcinoma: a single-institution study at a high-volume center in Japan.

The tumor-node-metastasis (TNM) staging system is most commonly adopted to evaluate the prognosis of patients with thyroid carcinoma. The 8th edition of the TNM staging system, an extensively revised version of the 7th edition, was recently released. We aimed to investigate whether and how well the 8th edition reflects the cause-specific survival (CSS) of patients with papillary thyroid carcinoma by analyzing the cases in 5,892 patients who underwent initial surgery at Kuma Hospital between 1987 and 2005. The median postoperative follow-up duration was 178 months (range: 6-357 months). One patient with T4b disease was excluded from the analysis. Overall, 116 (2.0%) patients died of thyroid carcinoma. The proportion of variance explained (PVE) for CSS in the 7th and 8th editions was 10.69 and 10.97, respectively. Using the 7th edition, CSS of patients with stage IVA and stage III disease was similar (p = 0.32). In contrast, using the 8th edition, CSS was poorer in stage II than in stage I (p < 0.001), in stage III than in stage II (p < 0.001), and in stage IVB than in stage III (p < 0.001). Similar results were observed for disease-free survival. Although we could not establish any objective evidence that the 8th edition is superior to the 7th edition, the 8th edition is simpler and more convenient, as it includes fewer stages and addresses the issue of the 7th edition where stage IVA and III patients had similar prognoses.

Prognostic value of the 8th tumor-node-metastasis classification for follicular carcinoma and poorly differentiated carcinoma of the thyroid in Japan.

Follicular thyroid carcinoma (FTC), a form of differentiated thyroid carcinoma, is the second most common malignancy arising from thyroid follicular cells. Recently, the tumor-node-metastasis (TNM) classification for differentiated thyroid carcinoma was revised from the 7th to the 8th edition. The diagnostic criteria for poorly differentiated carcinoma (PDC) were also updated in the latest World Health Organization (WHO) classification. In this study, we investigated whether these changes are appropriate for accurately predicting prognosis. Three hundred and twenty-nine patients diagnosed with postoperative pathologically confirmed FTC, who underwent initial surgery at our hospital between 1984 and 2004, were enrolled. For this study, patients were re-evaluated and diagnosed with FTC (N = 285) or PDC (N = 44) without typical nuclear findings of papillary thyroid carcinoma. For FTC, the 8th TNM classification was a more accurate predictor of prognosis than the 7th TNM classification. In the 8th TNM classification, cause-specific survival became significantly poorer from Stage I to IVB. The cause-specific survival of PDC based on the latest WHO classification was worse than, but did not significantly differ from, that of PDC based only on the former WHO classification. For PDC, neither of the TNM classifications could accurately predict prognosis. Taken together, we conclude that (1) the 8th TNM classification more accurately reflects the prognosis of FTC than the 7th TNM classification; (2) PDC based on the former WHO classification should be retained, at least in Japan; and (3) the TNM classification may not be suitable for predicting the prognosis of PDC.

Trends in the Implementation of Active Surveillance for Low-Risk Papillary Thyroid Microcarcinomas at Kuma Hospital: Gradual Increase and Heterogeneity in the Acceptance of This New Management Option.

BACKGROUND: Active surveillance (AS) of low-risk papillary thyroid microcarcinoma (PMC) was adopted as a management modality in both the Japanese guidelines in 2011 and the American Thyroid Association guidelines in 2015. AS was initiated at Kuma Hospital in 1993 but was not immediately accepted by all physicians. This study investigated the history of acceptance of AS at Kuma Hospital over time. The results should assist in the implementation of AS at other hospitals in Japan and other countries. METHODS: This study included 4023 patients who were cytologically diagnosed with low-risk PMC at Kuma Hospital during the 24-year period between October 1993 and June 2016. The trend in the frequency of AS use over time was analyzed, dividing the 24-year study period into five parts based on the change in frequency of AS use: 1993-1997, 1998-2002, 2003-2006, 2007-2013, and 2014-2016. RESULTS: The frequency of AS use in the present cohort was 65%. The frequency gradually increased from 30% in 1993-1997 to 88% in 2014-2016, with a slight decrease from 51% in 1998-2002 to 42% in 2003-2006. Until 2007, patients were mostly seen by surgeons, and the frequency of AS use varied remarkably among individual surgeons. Since 2007, the number of patients whose therapeutic strategies are determined by endocrinologists has increased, and the frequency of AS use for low-risk PMC by endocrinologists has been higher than that by surgeons. CONCLUSIONS: At Kuma Hospital, acceptance of AS for low-risk PMC gradually increased over the 24-year study period, but AS was not equally accepted by all physicians. Such variations in the acceptance of AS among individual physicians are also expected to exist in other hospitals. However, due to increasing evidence of the safety and superiority of AS over immediate surgery for this indolent disease, it is expected that AS will gain faster acceptance in other hospitals in Japan and around the world.

Severe Fertility Effects of sheepish Sperm Caused by Failure To Enter Female Sperm Storage Organs in Drosophila melanogaster.

In Drosophila, mature sperm are transferred from males to females during copulation, stored in the sperm storage organs of females, and then utilized for fertilization. Here, we report a gene named sheepish (shps) of Drosophila melanogaster that is essential for sperm storage in females. shps mutant males, although producing morphologically normal and motile sperm that are effectively transferred to females, produce very few offspring. Direct counts of sperm indicated that the primary defect was correlated to failure of shps sperm to migrate into the female sperm storage organs. Increased sperm motion parameters were seen in the control after transfer to females, whereas sperm from shps males have characteristics of the motion parameters different from the control. The few sperm that occasionally entered the female sperm storage organs showed no obvious defects in fertilization and early embryo development. The female postmating responses after copulation with shps males appeared normal, at least with respect to conformational changes of uterus, mating plug formation, and female remating rates. The shps gene encodes a protein with homology to amine oxidases, including as observed in mammals, with a transmembrane region at the C-terminal end. The shps mutation was characterized by a nonsense replacement in the third exon of CG13611, and shps was rescued by transformants of the wild-type copy of CG13611 Thus, shps may define a new class of gene responsible for sperm storage.

The ligand Sas and its receptor PTP10D drive tumour-suppressive cell competition.

Normal epithelial cells often exert anti-tumour effects against nearby oncogenic cells. In the Drosophila imaginal epithelium, clones of oncogenic cells with loss-of-function mutations in the apico-basal polarity genes scribble or discs large are actively eliminated by cell competition when surrounded by wild-type cells. Although c-Jun N-terminal kinase (JNK) signalling plays a crucial role in this cell elimination, the initial event, which occurs at the interface between normal cells and polarity-deficient cells, has not previously been identified. Here, through a genetic screen in Drosophila, we identify the ligand Sas and the receptor-type tyrosine phosphatase PTP10D as the cell-surface ligand-receptor system that drives tumour-suppressive cell competition. At the interface between the wild-type 'winner' and the polarity-deficient 'loser' clones, winner cells relocalize Sas to the lateral cell surface, whereas loser cells relocalize PTP10D there. This leads to the trans-activation of Sas-PTP10D signalling in loser cells, which restrains EGFR signalling and thereby enables elevated JNK signalling in loser cells, triggering cell elimination. In the absence of Sas-PTP10D, elevated EGFR signalling in loser cells switches the role of JNK from pro-apoptotic to pro-proliferative by inactivating the Hippo pathway, thereby driving the overgrowth of polarity-deficient cells. These findings uncover the mechanism by which normal epithelial cells recognize oncogenic polarity-deficient neighbours to drive cell competition.

Electron microscopic observation of the sagittal structure of Drosophila mature sperm.

Observation of sperm development and determination of their morphological characteristics are very important to the understanding of phylogenetic relationships and the study of sperm function during fertilization. Although ultrastructural studies of sperm development in the testes of the fruit fly Drosophila have been performed, there are few reports describing electron microscopic morphology of mature sperm, that is, those released from the testes to the seminal vesicles. Here, we present the first report of the sagittal organization of Drosophila sperm head and neck regions by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The head and tail structures of a mature sperm, for example, the acrosome, nucleus, and flagellum, were easy to distinguish by the morphological characteristics of the sperm surface by SEM. The morphological relationships between the surface and internal structures of mature sperm were confirmed by observing longitudinal sections with TEM. Our approach overcame the technical difficulties involved in sample preparation for electron microscopic observation of the Drosophila mature sperm head, and therefore, this study serves as an important foundation for future genetic dissection of sperm ultrastructure and function in male sterile mutants.

Elimination of Y chromosome-bearing spermatids during spermiogenesis in an autosomal sex-ratio mutant of Drosophila simulans.

Sex ratio distortion, which is commonly abbreviated as sex-ratio, has been studied in many Drosophila species, but the mechanism remains largely unknown. Here, we report on the sex-ratio mutant of D. simulans named excess of females (exf). The third chromosomal recessive mutation results in a sex ratio of approximately 0.2 or less (males/total). Cytological observation demonstrated that meiosis appeared to be completed normally, but that most Y chromosome-bearing nuclei failed to elongate during spermiogenesis, as revealed by fluorescence in situ hybridization using sex chromosome-specific probes. These aberrant nuclei contained membranous inclusions as revealed by electron microscopic analysis. Most of the aberrant exf spermatids failed to individualize and mature, suggesting that a later stage of spermiogenesis is involved in prevention of production of sperm with abnormal morphology. On the one hand, in exf seminal vesicles, sperm nuclei with a length of 5-8.5 µm were occasionally observed, in addition to those with wild-type sperm dimensions, that is, a length of approximately 10 µm. Thus, spermatids with less severe nuclear defects can escape elimination and be released into the seminal vesicles as mature sperm. Furthermore, we constructed His2AvD-GFP and ProtamineB-eGFP transgenic lines in D. simulans, and examined the processes involved in replacement of chromatin proteins over a time course, according to nuclear morphology. We found that both normal and abnormal sperm heads demonstrated equal chromatin replacement during late spermiogenesis. Our results suggest that exf belongs to a unique class of meiotic drive systems in that (1) intranuclear membranous inclusions cause failure of nuclear shaping of Y-bearing spermatids without affecting the histone-protamine transition, and (2) a portion of the aberrant spermatids differentiate into mature sperm; these are transferred to and stored by females.