Musician developed left putaminal hemorrhage and lost absolute pitch ability-case report.

Absolute pitch (AP) recognizes and labels the pitch chroma of a given tone without external reference. Its neural mechanism remains unclear. We report a 68-year-old AP musician who developed a left putaminal hemorrhage edematous lesion under the posterior insular cortex. Diffusion tensor tractography with the region of interest, including Heschl's gyrus, was performed. In the left hemisphere, the middle longitudinal fasciculus was absent, especially at the parietal lobe. Her AP ability was lost. As the hematoma was absorbed and the left MdLF was observed on the tractography, her AP ability recovered. Our case suggested that the left middle longitudinal fasciculus, a part of the ventral auditory pathway, plays a role in AP.

[Posterior reversible encephalopathy syndrome following paralytic ileus caused by vincristine in a patient with T cell lymphoblastic lymphoma].

A 22-year-old woman presented with high fever, chest tightness and cough in January 20XX. Since CT scans revealed an anterior mediastinal mass, percutaneous needle biopsies of the mass were performed and she was diagnosed with T-cell lymphoblastic lymphoma (T-LBL). After the immunophenotype of lymphocytes in her pleural effusion had been identified, she received CHOP therapy because her dyspnea worsened, and induction therapy for acute lymphoblastic leukemia was subsequently performed after confirmation of her diagnosis as T-LBL. During this induction therapy, she developed paralytic ileus. One week thereafter, she suddenly exhibited visual disturbance, headache and nausea. Her cerebrospinal fluid was normal. Magnetic resonance imaging showed symmetrical high signal intensities on T2-weighted and fluid-attenuated inversion recovery images, and low signal intensities on T1-weighted images in the cortical and subcortical white matter of the posterior parietal and occipital lobes. Based on these findings, she was diagnosed as having posterior reversible encephalopathy syndrome (PRES). During chemotherapy for hematologic malignancies, some patients with PRES reportedly develop paralytic ileus or tumor lysis syndrome. PRES should be considered in patients with neurological abnormalities following such complications during chemotherapy.

Inhibition of CUTIN DEFICIENT 2 Causes Defects in Cuticle Function and Structure and Metabolite Changes in Tomato Fruit.

Tomato (Solanum lycopersicum) fruit cuticle has been extensively studied due to its effect on the biochemical and physiological properties of the fruit. To date, several tomato mutants defective in proper cuticle formation have been identified. To gain insight into tomato cuticle formation, we investigated one such mutant, sticky peel/light green (pe lg). We verified the responsible gene by fine mapping and obtained the same conclusion as a previous report. To elucidate the pleiotropic effects of cuticle deficiency caused by the cd2 mutation, CD2 suppression lines were constructed. As found in the pe lg mutant, the suppression lines showed enhanced water permeability and aberrant leaf and fruit cuticles. Water use efficiency of the suppression line was lower than that of the wild type. However, photosynthetic ability was not affected in the suppression line. Since these phenotypes are related to altered deposition of wax and cutin, other lipidic metabolites might be changed, too. To confirm this hypothesis, we conducted metabolite profiling. The metabolite profiling revealed that not only lipid but also sugar, flavonoid and glycoalkaloid metabolites in fruit were changed in the cd2 mutant. These results indicate that CD2 is essential both for normal cutin and wax deposition and for proper accumulation of specific metabolites in tomato fruit.

Sarcomatoid mesothelioma diagnosed in a patient with mesothelioma in situ: a case report on morphologic differences after 9-month interval with details analysis of cytology in early-stage mesothelioma.

BACKGROUND: Overlapping morphological features of mesothelial cells have been rendered it difficult to distinguish between reactive and malignant conditions. The development of methods based on detecting genomic abnormalities using immunohistochemistry and fluorescence in situ hybridization have contributed markedly to solving this problem. It is important to identify bland mesothelioma cells on cytological screening, perform efficient genomic-based testing, and diagnose mesothelioma, because the first clinical manifestation of pleural mesothelioma is pleural effusion, which is the first sample available for pathological diagnosis. However, certain diagnostic aspects remain challenging even for experts. CASE PRESENTATION: This report describes a case of a 72-year-old man with a history of asbestos exposure who presented with pleural effusion as the first symptom and was eventually diagnosed as mesothelioma. Mesothelioma was suspected owing to prominent cell-in-cell engulfment in mesothelial cells on the first cytological sample, and the diagnosis of mesothelioma in situ was confirmed by histology. Unexpectedly, sarcomatoid morphology of mesothelioma was found in the second pathology samples 9 months after the first pathological examination. Both the mesothelioma in situ and invasive lesion showed immunohistochemical loss of methylthioadenosine phosphorylase (MTAP) and homozygous deletion of cyclin dependent kinase inhibitor 2A (CDKN2A) on fluorescence in situ hybridization. The patient received medication therapy but died of disease progression 12 months after the diagnosis of the sarcomatoid morphology of mesothelioma. CONCLUSION: Our case suggests that cell-in-cell engulfment can be conspicuous in early-stage mesothelioma with inconspicuous nuclear atypia and few multinucleated cells. In addition, the presence of MTAP loss and CDKN2A homozygous deletion are suspected to be involved in early formation to invasive lesions and/or sarcomatoid morphology. We believe that it is important to consider genetic abnormalities when deciding on individual patient management. Furthermore, cases of mesothelioma, even those of an in situ lesion, with MTAP loss and/or CDKN2A deletion should be carefully followed up or subjected to early treatment.

Overexpression of neurotrophin-3 stimulates a second wave of dopaminergic amacrine cell genesis after birth in the mouse retina.

Dopaminergic amacrine (DA) cells play multiple and important roles in retinal function. Neurotrophins are known to modulate the number and morphology of DA cells, but the underlying regulatory mechanisms are unclear. Here, we investigate how neurotrophin-3 (NT-3) regulates DA cell density in the mouse retina. We demonstrate that overexpression of NT-3 upregulates DA cell number and leads to a consequent increase in the density of DA cell dendrites. To examine the mechanisms of DA cell density increase, we further investigate the effect of NT-3 overexpression on retinal apoptosis and mitosis during development. We find that NT-3 does not affect the well known wave of retinal cell apoptosis that normally occurs during the first 2 weeks after birth. Instead, overexpression of NT-3 promotes additional mitosis of DA cells at postnatal day 4, but does not affect cell mitosis before birth, the peak period of amacrine cell genesis in wild-type retinas. We next show that retinal explants cultured from birth to day 7 without extra NT-3 produced by lens exhibit similar number of DA cells as in wild type, further supporting the notion that postnatal overexpression of lens-derived NT-3 affects DA cell number. Moreover, the additional mitosis after birth in NT-3-overexpressing mice does not occur in calretinin-positive amacrine cells or PKC-positive rod ON bipolar cells. Thus, the NT-3-triggered wave of cell mitosis after birth is specific for the retinal DA cells.

A novel class of sticky peel and light green mutations causes cuticle deficiency in leaves and fruits of tomato (Solanum lycopersicum).

The plant cuticle consists of aliphatic wax and cutin, and covers all the aerial tissues, conferring resistance to both biotic and abiotic stresses. In this study, we performed phenotypic characterizations of tomato mutants having both sticky peel (pe) and light green (lg) mutations. Our genetic analysis showed that these two mutations are tightly linked and behave like a monogenic recessive mutation. The double mutant (pe lg) produced glossy soft fruits with light green leaves, most likely due to defects in cuticle formation. Cytological analysis revealed that the thickness of the fruit cuticle layer was dramatically reduced in the pe lg mutant. The epidermal cells of the leaves were also deformed in the pe lg mutant, suggesting that leaf cuticle formation was also disrupted in the mutant. Consistent with this, transmission electron microscopic analysis showed that the electron density of the cuticle layer of the adaxial surface of the leaf was reduced in the pe lg mutant compared to WT, suggesting that there are changes in cuticle structure and/or composition in the pe lg mutant. Both physiological analysis to measure the rate of transpiration, and staining of the fruits and leaves with toluidine blue, revealed that water permeability was enhanced in the pe lg mutant, consistent with the reduced thickness of its cuticle layer. Taken together the preliminary analyses of the cuticle components, the PE LG is most likely involved in proper cuticle formation.

Sonographic visualization of nipple blood flow can help differentiate Paget disease from benign eczematous nipple lesions.

PURPOSE: Paget disease of the breast is a rare cancer that originates from the nipple-areolar complex. It is often overlooked and misdiagnosed as benign chronic eczema of the nipple. We aimed to retrospectively verify whether blood flow analysis using Doppler sonography was useful for detecting the presence of Paget disease. METHODS: In this retrospective study, 12 patients with pathologically proven unilateral nipple eczematous lesions (seven with Paget disease and five with simple dermatitis) were included. Nipple blood flow signal was observed using Doppler sonography, and the detected blood flow signals were quantified using digitally recorded images. Quantified blood flow ratio and pathologically examined capillary density were evaluated between affected and unaffected nipples. Findings of mammography, grayscale sonography, and contrast-enhanced magnetic resonance imaging (CE-MRI) were reviewed. RESULTS: In patients with Paget disease, Doppler effects in the affected nipple were more clearly visible than those in the unaffected nipple. These effects were sufficiently visible to identify Paget disease. No obvious effects were observed in the affected and unaffected nipples of simple dermatitis. The quantified blood flow ratio and pathologically examined capillary density were significantly higher for the Paget lesion than those for the non-Paget lesion. The sensitivity of CE-MRI and Doppler sonography was markedly correlated, revealing blood flow changes in the nipple lesions of Paget disease. CONCLUSION: Doppler sonography visualized the proliferation of blood vessels in Paget lesions. The visualization of increased nipple blood flow using Doppler sonography is a simple and low-cost method that provides useful data for identifying Paget disease during routine medical care.

Neuroprotective effect of transcorneal electrical stimulation on the acute phase of optic nerve injury.

PURPOSE: Traumatic optic neuropathy often induces a loss of vision that proceeds rapidly within several hours, together with retinal ganglion cell death, in a much slower time course. Electrical stimulation has previously been shown to rescue injured retinal ganglion cells from cell death. The present study tests whether transcorneal electrical stimulation could preserve visual function after an optic nerve crush. METHODS: Transcorneal electrical stimulation was given immediately after a calibrated optic nerve crush. We measured visually evoked potentials (VEPs) in the visual cortex of rats before and immediately after the optic nerve crush and after the transcorneal stimulation to estimate an extent of damage and effects of stimulation in individual animals. In addition, the retinal axons were labeled with a fluorescent anterograde tracer to determine whether the transcorneal electrical stimulation can protect the retinal axons from degeneration. RESULTS: The optic nerve crush was made at an intensity that does not allow a spontaneous recovery of VEP for 1 week. The transcorneal stimulation immediately increased VEP amplitude impaired by the optic nerve crush, and this augmentation was often preserved after 1 week. In the stimulated animals, a larger amount of retinal axons projected centrally beyond the crushed region in comparison to the unstimulated animals. CONCLUSIONS: Transcorneal electrical stimulation would restore the functional impairment of optic nerve by traumatic injury at a very early stage and protect retinal axons from the ensuing degeneration.

Recurrence after sentinel lymph node biopsy with or without axillary lymph node dissection in patients with breast cancer.

BACKGROUND: A regional nodal recurrence is a major concern after a sentinel lymph node biopsy (SLNB) alone in patients with breast cancer. In this study we investigated patterns and risk factors of regional nodal recurrence after SLNB alone. PATIENTS AND METHODS: Between January 1999 and March 2005, a series of 1,704 consecutive breast cancer cases in 1,670 patients (34 bilateral breast cancer cases) with clinically negative nodes or suspicious nodes for metastasis who underwent SLNB at a single institute (Saitama Cancer Center) were studied. All 1,704 cases were classified based upon presence or absence of a metastatic lymph node, treated with or without axillary lymph node dissection (ALND). The site of first recurrence was classified as local, regional node, or distant. The regional node recurrences were subclassified as axillary, interpectoral, infraclavicular, supraclavicular, or parasternal. RESULTS: After a median follow-up period of 34 months (range, 2-83 months), first recurrence occurred in local sites in 32 (1.9%) cases, regional nodes in 26 (1.5%) cases, and distant sites in 61 (3.6%) cases. In 1,062 cases with negative nodes treated without ALND and 459 cases with positive nodes treated with ALND, 11 (1.0%) and 15 (3.3%) recurred in regional nodes, respectively, and 4 (0.4%) and 2 (0.6%) recurred in axillary nodes, respectively. Of 822 cases of invasive breast cancer with negative nodes treated with SLNB alone, 10 (1.4%) recurred in regional nodes, and 4 (0.5%) recurred in axillary nodes. In the 10 patients with regional nodal failure, all of the tumors were negative for estrogen receptor (ER) and/or progesterone receptor (PR) and were nuclear grade (NG) 3. CONCLUSIONS: The axillary recurrence rate was low in patients treated with SLNB alone. Omitting ALND is concluded to be safe after adequate SLNB. Risk factors for regional nodal failure after SLNB alone are negative hormone receptor status and high NG.

Streptococcal toxic-shock syndrome due to Streptococcus dysgalactiae subspecies equisimilis in breast cancer-related lymphedema: a case report.

BACKGROUND: Breast cancer-related lymphedema often causes cellulitis and is one of the most common complications after breast cancer surgery. Streptococci are the major pathogens underlying such cellulitis. Among the streptococci, the importance of the Lancefield groups C and G is underappreciated; most cases involve Streptococcus dysgalactiae subspecies equisimilis. Despite having a relatively weak toxicity compared with group A streptococci, Streptococcus dysgalactiae subspecies equisimilis is associated with a mortality rate that is as high as that of group A streptococci in cases of invasive infection because Streptococcus dysgalactiae subspecies equisimilis mainly affects elderly individuals who already have various comorbidities. CASE PRESENTATION: An 83-year-old Japanese woman with breast cancer-related lymphedema in her left upper limb was referred to our hospital with high fever and acute pain with erythema in her left arm. She showed septic shock with disseminated intravascular coagulation. Blood culture showed positive results for Streptococcus dysgalactiae subspecies equisimilis, confirming a diagnosis of streptococcal toxic-shock syndrome. She survived after successful intensive care. CONCLUSIONS: To the best of our knowledge, this case represents the first report of Streptococcus dysgalactiae subspecies equisimilis-induced streptococcal toxic-shock syndrome in a patient with breast cancer-related lymphedema. Breast cancer-related lymphedema is a common problem, and we must pay attention to invasive streptococcal soft tissue infections, particularly in elderly patients with chronic disease.

Cytogenetically Unrelated Clones in Acute Myeloid Leukemia Showing Different Responses to Chemotherapy.

We report a case of acute myeloid leukemia (AML) with two cytogenetically unrelated clones. The patient was a 45-year-old male who was diagnosed with acute monoblastic leukemia (AMoL). Initial G-band analysis showed 51,XY,+6,+8,inv(9)(p12q13)c,+11,+13,+19[12]/52,idem,+Y[8], but G-band analysis after induction therapy showed 45,XY,-7,inv(9)(p12q13)c[19]/46,XY,inv(9)(p12q13)c[1]. Retrospective FISH analysis revealed a cryptic monosomy 7 clone in the initial AML sample. The clone with multiple trisomies was eliminated after induction therapy and never recurred, but a clone with monosomy 7 was still detected in myelodysplastic marrow with a normal blast percentage. Both clones were successfully eliminated after related peripheral blood stem cell transplantation, but the patient died of relapsed AML with monosomy 7. We concluded that one clone was de novo AMoL with chromosome 6, 8, 11, 13, and 19 trisomy and that the other was acute myeloid leukemia with myelodysplasia-related changes(AML-MRC) with chromosome 7 monosomy showing different responses to chemotherapy. Simultaneous onset of cytogenetically unrelated hematological malignancies that each have a different disease status is a rare phenomenon but is important to diagnose for a correct understanding of the disease status and for establishing an appropriate treatment strategy.

A combination phase I study of weekly paclitaxel and doxifluridine in advanced gastric cancer patients.

BACKGROUND: Preclinical studies have shown that paclitaxel and doxifluridine can act synergistically without overlapping toxicity for the treatment of advanced gastric cancer. The objectives of this study were to determine the maximum tolerated dose (MTD), the dose-limiting toxicity and the recommended Phase II dose for this drug combination. PATIENTS AND METHODS: Patients with histologically confirmed gastric cancer were eligible for the study. The paclitaxel dose (days 1, 8, 15) was augmented with a fixed dose of for treatments (1-3). doxifluridine (533 mg/m2, 5 days/week) on a 28-day cycle. RESULTS: Eighteen patients were enrolled. The MTD was not reached until the highest dose level. One patient had Grade 3 myelosuppression. The responses of the 13 suitable patients included 1 complete response and 5 partial responses. CONCLUSION: Although the MTD level could not be definitively which is a established, upon consideration of the lengthy administration time and the effectiveness, the recommended Phase II dose of paclitaxel was concluded to be 80 mg/m2 in combination with doxifluridine at 533 mg/m2.

Two cases of breast cancer with cartilaginous and osseous metaplasia.

Invasive breast cancer (IBC) with cartilaginous or osseous metaplasia is rare. Here we report two cases of this unusual variation. Case 1: The patient was a 33-year-old woman with a right breast tumor, 2.2 cm in size. Mammograms (MMG) presented no specific findings, but ultrasound (US) showed a cystic-like lesion. Excisional biopsy confirmed IBC with cartilaginous and osseous metaplasia. Biopsy was followed with a modified radical mastectomy. One lymph node was positive, and both estrogen receptor (ER) and progesterone receptor (PgR) were negative. Case 2: The patient was a 43-year-old woman with a left breast tumor, 4.2 cm in size. MMGs presented no findings but US showed an irregular shaped, low-echoic area, suggesting malignancy. Core needle biopsy confirmed IBC with cartilaginous metaplasia. A total adenectomy and lymph node dissection with breast reconstruction using a lattisimus dorsi muscle flap were performed. Two of 18 lymph nodes were positive for metastasis and both ER and PgR were negative. IBC with cartilaginous or osseus metaplasia seem to be divided into two types pathologically, with or without intervening spindle cells, which is related to the prognosis. Matrix producing carcinoma (MPC) has no intervening spindle cells and a better prognosis than other types, however, MPC has been reported to have the same prognosis as ordinary breast cancer after for adjusting its stage. Our two cases were MPC's and no recurrence has been detected 5 and 3 years from the initial therapy, respectively.

Advanced gastric cancer with peritoneal dissemination successfully treated with paclitaxel and doxifluridine: a case report.

A 50-year-old female presenting with severe ascites and anemia and diagnosed with advanced gastric cancer was admitted to our hospital. Endoscopic examination revealed an edematous lesion with redness and a giant fold in the stomach with poor expansion. The histological examination of biopsy specimens from the edematous lesion revealed signet-ring-cell carcinoma. Computed tomography demonstrated a thickening of the gastric wall, severe ascites, and peritoneal dissemination in the Douglas pouch. Paclitaxel (70mg/m2) was administered to the patient on days 1, 8, and 15, with doxifluridine (533mg/m2) for five days per week, on a 28-day cycle. By completion of the first course of treatment, the ascites had disappeared, the tumor in the Douglas pouch had shrunk, and the thickening of the gastric wall had lessened. In addition, the fold in the stomach appeared by endoscopic examination to have resumed its normal thickness, no malignant cells were detected in a biopsy, and the thymidine phosphorylase activity in the tumor tissue was two-fold greater than that before chemotherapy. After three treatment courses, the number of apoptotic cells had apparently increased compared with the prechemotherapy number. The only adverse drug reactions that were observed were grade 2 alopecia and grade 1 myalgia. After thirteen courses of chemotherapy over the past one year, both primary and metastatic lesions seem to be regressing. This case study suggests that paclitaxel plus doxifluridine therapy is effective and well-tolerated in non-resectable gastric cancer patients.

Immunohistochemical double staining with estrogen receptor and HER2 on primary breast cancer.

Immunohistochemical double staining with estrogen receptor (ER) and epidermal growth factor receptor 2 (HER2) was conducted in tissue sample of 125 women with invasive breast cancer. The age at the time of surgery ranged from 28 to 82 years. The tumor size was 2 cm or less in 42 patients and larger than 2 cm in 83. Axillary lymph node status was positive in 53 patients and negative in 72. Estrogen receptor (ER) which was measured using enzyme immunoassay (EIA) was positive in 67 patients, negative in 50 and unknown in 8. Of the 125 patients evaluated, 83 (66.4%) were immunohistochemically positive for ER. ER by immunohistochemistry (IHC) (ER-IHC) was significantly (p<0.01) correlated with ER by EIA (ER-EIA). ER-EIA values in ER-IHC scores were 1.4 fmol/mg protein in score 0, 0.0 in score 1, 19.0 in score 3, 21.2 in score 4, 12.2 in score 5, 17.6 in score 6, 30.0 in score 7 and 114.8 in score 8. ER-EIA values in ER-IHC-score 8 were significantly higher than in scores 0, 2, 3, 4, 5, 6 and 7. Of the 125 patients, 35 (28%) were immunohistologically positive for HER2. HER2 expression was inversely correlated with ER expression. When evaluated even in ER-positive patients, HER2 overexpression was associated with lower ER levels. In this study, we conducted immunohistochemical double staining with ER and HER2, and demonstrated that low ER levels might be one factor in the relative resistance of HER2-positive and ER-positive tumors to hormonal therapy.

Long-term suppression of lymphangitic lung metastasis from breast cancer using biweekly docetaxel: a case report.

A 45-year-old woman underwent a modified radical mastectomy for right breast cancer in July 1996. As lymph node metastases were quite advanced, chemotherapy was started with anthracyclines. Four years after surgery, cough and dyspnea appeared. Chest radiograph and CT showed reticular shadows bilaterally and slight pleural effusion, suggesting lymphangitic lung metastasis of breast cancer. Biweekly intravenous docetaxel (TXT,45 mg/m2) was initiated. Four courses of TXT ameliorated her complaints and radiographic findings. A total of 30 continuous courses of TXT suppressed disease exacerbation for 18 months until new lesions manifested in January 2002. The main side effects were grade 2 leukopenia and alopecia. This case report describes a patient with long-term suppression of lymphangitic lung metastasis of breast cancer using biweekly TXT without severe side effects or worsening quality of life.

Primary amenorrhea accompanied by adrenal adenoma: start of menarche soon after tumor resection.

We report a patient with primary amenorrhea accompanied by adrenal adenoma. A 21-year-old woman was admitted to our hospital because of primary amenorrhea and hyperprogesteronemia without virilization. Venous sampling showed progesterone overproduction at the left adrenal gland. Computed tomography revealed a 7 cm mass in left adrenal gland. Serum pregnenorone, 17-hydroxypregnenorone, dehydroepiandrosterone, 17-hydroxyprogesterone, deoxycorticosterone, and 11-deoxycortisol were elevated. The diagnosis of steroid hormone producing tumor was made. Following tumor resection, serum progesterone normalized 4 days later, and menarche occurred 51 days after operation. The present case indicated that adrenal functioning tumor should not be overlooked in patients with primary amenorrhea.

Validation of Urdu Interaction with Disabled Persons scale.

This study developed a valid and reliable Urdu language measure that can be used for assessing attitudes toward persons with physical disability in Pakistan. The Interaction with Disabled Persons scale (IDP), which measures attitudes of discomfort with interaction with disabled people, is a scale with established validity and reliability in English and other languages. An Urdu translation was back-translated to English and then reviewed by a committee to develop cultural validity. Data were collected from 591 Urdu-speaking Pakistani people. Factor analysis extracted four factors that accounted for 55% of the variance and reflected factors found in 12 previous studies. Cronbach's alpha described moderate internal consistency for the IDP.

[Metastatic breast cancer treated with trastuzumab and paclitaxel--a case report with clinically complete response].

A 60-year-old woman who had undergone a total glandectomy for non-invasive ductal carcinoma of the left breast at the age of 56 in another hospital had a local recurrence in the left preserved breast. The patient was referred to our hospital and underwent a mastectomy. After surgery, treatment of UFT and CPA was started. Seven months after surgery, metastasis occurred at the left supraclavicular lymph node, and CPA, THP-adriamycine and 5-FU therapy was started. Fourteen months after surgery, skin redness of the left upper arm, the left chest wall and contralateral breast, and a contralateral axillary lymph node swelling were recognized. Neither docetaxel nor mitoxantrone-combined therapy was effective. Trastuzumab therapy was started because of HER2 overexpression by immunohistochemistry, and partial response was received after 7 weeks. Four months later, multiple nodules in the chest wall were recognized, and weekly treatment of trastuzumab and paclitaxel was started. Skin redness and multiple nodules in the chest wall completely disappeared after 3 months. No recurrence has been found for 14 months.

Sustained ocular hypertension induces dendritic degeneration of mouse retinal ganglion cells that depends on cell type and location.

PURPOSE: Glaucoma is characterized by retinal ganglion cell (RGC) death and frequently associated with elevated IOP. How RGCs degenerate before death is little understood, so we sought to investigate RGC degeneration in a mouse model of ocular hypertension. METHODS: A laser-induced mouse model of chronic ocular hypertension mimicked human high-tension glaucoma. Immunohistochemistry was used to characterize overall RGC loss and an optomotor behavioral test to measure corresponding changes in visual capacity. Changes in RGC functional properties were characterized by a large-scale multielectrode array (MEA). The transgenic Thy-1-YFP mouse line, in which a small number of RGCs are labeled with yellow fluorescent protein (YFP), permitted investigation of whether subtypes of RGCs or RGCs from particular retinal areas were differentially vulnerable to elevated IOP. RESULTS: Sustained IOP elevation in mice was achieved by laser photocoagulation. We confirmed RGC loss and decreased visual acuity in ocular hypertensive mice. Furthermore, these mice had fewer visually responsive cells with smaller receptive field sizes compared to controls. We demonstrated that RGC dendritic shrinkage started from the vertical axis of hypertensive eyes and that mono-laminated ON cells were more susceptible to IOP elevation than bi-laminated ON-OFF cells. Moreover, a subgroup of ON RGCs labeled by the SMI-32 antibody exhibited significant dendritic atrophy in the superior quadrant of the hypertensive eyes. CONCLUSIONS: RGC degeneration depends on subtype and location in hypertensive eyes. This study introduces a valuable model to investigate how the structural and functional degeneration of RGCs leads to visual impairments.