Volume electron microscopy reveals age-related ultrastructural differences of globular bush cell axons in mouse central auditory system

In mammals, thick axonal calibers wrapped with heavy myelin sheaths are prevalent in the auditory nervous system. These features are crucial for fast traveling of nerve impulses with minimal attenuation required for sound signal transmission. In particular, the long-range projections from the cochlear nucleus - the axons of globular bush cells (GBCs) - to the medial nucleus of the trapezoid body (MNTB) are tonotopically organized. However, it remains controversial in gerbils and mice whether structural and functional adaptations are present among the GBC axons targeting different MNTB frequency regions. By means of high-throughput volume electron microscopy, we compared the GBC axons in full-tonotopy-ranged MNTB slices from the C57BL/6 mice at different ages. Our quantification reveals distinct caliber diameter and myelin profile of the GBC axons with endings at lateral and medial MNTB, arguing for modulation of functionally heterogeneous axon subgroups. In addition, we reported axon-specific differences in axon caliber, node of Ranvier, and myelin sheath among juvenile, adult, and old mice, indicating the age-related changes of GBC axon morphology over time. These findings provide structural insight into the maturation and degeneration of GBC axons with frequency tuning across the lifespan of mice.

Real-time threshold determination of auditory brainstem responses by cross-correlation analysis

Auditory brainstem response (ABR) serves as an objective indication of auditory perception at a given sound level and is nowadays widely used in hearing function assessment. Despite efforts for automation over decades, ABR threshold determination by machine algorithms remains unreliable and thereby one still relies on visual identification by trained personnel. Here, we described a procedure for automatic threshold determination that can be used in both animal and human ABR tests. The method terminates level averaging of ABR recordings upon detection of time-locked waveform through cross-correlation analysis. The threshold level was then indicated by a dramatic increase in the sweep numbers required to produce “qualified” level averaging. A good match was obtained between the algorithm outcome and the human readouts. Moreover, the method varies the level averaging based on the cross-correlation, thereby adapting to the signal-to-noise ratio of sweep recordings. These features empower a robust and fully automated ABR test.

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Automatic threshold determination of auditory brainstem response (ABR)

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Detection of “clear” responses from iteratively averaged level representation

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Wide application in both animal and human ABR tests

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Stop on-going level averaging based on detection outcome

Comparing the bone mineral density among male patients with latent autoimmune diabetes and classical type 1 and type 2 diabetes, and exploring risk factors for osteoporosis

AIMS

This study aimed to compare the bone mineral densities (BMDs) among male patients with latent autoimmune diabetes in adults (LADA), classical type 1 diabetes (T1DM), and type 2 diabetes (T2DM), and to examine the risk factors for developing low BMD in these patients.

PATIENTS AND METHODS

Between January 2017 and October 2020, a total of 57, 67, and 223 male patients with LADA, classical T1DM, and T2DM, respectively, were recruited from the endocrinology department of Shanghai Tenth People's Hospital. Hormonal markers of bone metabolism, lipid profiles, uric acid, glycosylated hemoglobin A1c (HbA1c), and beta-cell function were measured using blood samples. BMD was measured at the lumbar spine, femoral neck, and right hip by dual-energy X-ray absorptiometry.

RESULTS

The mean BMD values from all three skeletal sites in male patients with LADA were comparable to those with classical T1DM but were much lower than those with T2DM. After adjusting for confounding factors, multiple linear regression analysis demonstrated that in all male patients with diabetes, body mass index (BMI), uric acid, and fasting C-peptide showed significant positive associations with BMD at all three skeletal sites; however, osteocalcin showed a negative association at all three sites.

CONCLUSIONS

Compared with male patients with T2DM, lower BMDs were observed in patients with LADA and T1DM. Low BMI, uric acid, C-peptide levels, and high osteocalcin levels are risk factors for developing low BMD in male patients with diabetes.

MiR-429-5p attenuates the migration and invasion of malignant melanoma by targeting LIMK1

OBJECTIVE

To investigate the potential effects of microRNA-429-5p (miR-429-5p) on the development of malignant melanoma (MM) and the relevant mechanism.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was used to detect the differential expression of miR-429-5p in MM tissues. The relationship between miR-429-5p expression and clinical pathological data of MM patients was analyzed. LIM kinase 1 (LIMK1) was verified as a downstream target of miR-429-5p by online prediction software, and the interaction between LIMK1 and miR-429-5p was verified by Dual-Luciferase reporter assay.

RESULTS

Compared with normal skin tissues, miR-429-5p was downregulated in MM tissues. MiR-429-5p expression was correlated with tumor size and stage of MM. Upregulation of miR-429-5p significantly inhibited protein expression of LIMK1 and reduced migration and invasion ability of MM cells. LIMK1 was involved in MM progression regulated by miR-429-5p.

CONCLUSIONS

MiR-429-5p attenuates migration and invasion in MM by targeting LIMK1. Hence, miR-429-5p/LIMK1 axis might be a potential therapeutic target for the treatment of MM.

Comparison of Two-Step Transient Evoked Otoacoustic Emissions and One-Step Automated Auditory Brainstem Response for Universal Newborn Hearing Screening Programs in Remote Areas of China

Objective: To compare the hearing screening results of two-step transient evoked otoacoustic emissions (TEOAE) and one-step automatic auditory brainstem response (AABR) in non-risk newborns, and to explore a more suitable hearing screening protocol for infants discharged within 48 h after birth in remote areas of China. Methods: To analyze the age effect on pass rate for hearing screening, 2005 newborns were divided into three groups according to screening time after birth: <24, 24-48, and 48-72 h. All subjects received TEOAE + AABR test as first hearing screen, and those who failed in any test were rescreened with TEOAE + AABR at 6 weeks after birth. The first screening results of AABR and TEOAE were compared among the three groups. The results of two-step TEOAE screening and one-step AABR screening were compared for newborns who were discharged within 48 h. The time spent on screening was recorded for TEOAE and AABR. Results: The pass rate of TEOAE and AABR increased significantly with the increase of first screening time (P < 0.05), and the false positive rate decreased significantly with the increase of first screening time (P < 0.05). The failure rate of first screening of AABR within 48 h was 7.31%, which was significantly lower than that of TEOAE (9.93%) (P < 0.05). The average time spent on AABR was 12.51 ± 6.36 min, which was significantly higher than that of TEOAE (4.05 ± 1.56 min, P < 0.05). The failure rate of TEOAE two-step screening was 1.59%, which was significantly lower than one-step AABR. Conclusions: Compared with TEOAE, AABR screening within 48 h after birth can reduce the failure rate and false positive rate of first screening. However, compared with TEOAE two-step screening, one-step AABR screening has higher referral rate for audiological diagnosis. In remote areas of China, especially in hospitals with high delivery rate, one-step AABR screening is not feasible, and two-step TEOAE screening protocol is still applicable to UNHS screening as more and more infants discharged within 48 h after birth.

[Functional Characterization of ZmHAK1 Promoter and Its Regulatory Transcription Factors in Maize]

Potassium (K^(+)) deficiency in the soil may seriously affect the yield and quality of plants, which usually satisfy their potassium requirements by engaging their K^(+) transporters and/or channels. High-affinity potassium transporter (ZmHAK) family members play crucial role in the uptake and distribution of K^(+) in maize (Zea mays L.). Here, we describe the function of ZmHAK1 promoter and its upstream regulatory transcription factors in maize. In this plant, HAK gene family includes 34 protein-encoding members, with their phylogenetic tree analysis showing both evolutionary conservativeness and diversity. ZmHAK1 gene promoter contains many functional elements related to abiotic stress. Reporter construct pCambia1301:ProZmHAK1:GUS shows that the ZmHAK1 gene is active in the roots, stems, and leaves. Using yeast one-hybrid experiment, we showed that the ZmHAK1 promoter interacts with the transcription factors ZmRAP2.11 and ZmARF2, and that these interactions occur on different fragments of the ZmHAK1 promoter. Transcription factor ZmRAP2.11 localizes in the nucleus, while ZmARF2 is found both in the nucleus and in the cell cytoplasm. In conclusion, our results suggest that the ZmHAK1 regulation has an important role in the process of absorbing potassium ions, and possibly in the response of maize to abiotic stress.

Novel variants and uncommon cases among southern Chinese children with X-linked hypophosphatemia

PURPOSE

X-linked hypophosphatemia (XLH) is the most common inherited renal phosphate wasting disorder and is often misdiagnosed as vitamin D deficiency. This study aims to provide clinical and mutational characteristics of 65 XLH pediatric patients in southern China.

METHODS

In this work, a combination of DNA sequencing and qPCR analysis was used to study the PHEX gene in 80 pediatric patients diagnosed with hypophosphatemia. The clinical and laboratory data of confirmed 65 XLH patients were assessed and analyzed retrospectively.

RESULTS

In 65 XLH patients from 61 families, 51 different variants in the PHEX gene were identified, including 23 previously reported variants and 28 novel variants. In this cohort of XLH patients, the c.1601C>T(p.Pro534Leu) variant appears more frequently. Fourteen uncommon XLH cases were described, including four boys with de novo mosaic variants, eight patients with large deletions and a pair of monozygotic twins. The clinical manifestations in this cohort are very similar to those previously reported.

CONCLUSION

This study extends the mutational spectrum of the PHEX gene, which will contribute to accurate diagnosis. This study also suggests a supplementary qPCR or MLPA assay may be performed along with classical sequencing to confirm the gross insertion/deletion.

The relationship between atherosclerosis and bone mineral density in patients with type 2 diabetes depends on vascular calcifications and sex

It is unknown whether a relationship exists between bone mineral density (BMD) and atherosclerosis with or without vascular calcification. In our study, a negative correlation between carotid atherosclerosis and BMD was found in female T2DM patients with vascular calcification, but not in those without calcification and males.

INTRODUCTION

Atherosclerosis is considered associated with low bone mineral density (BMD). However, most previous studies focus on patients with arterial atherosclerosis with vascular calcification. It is still unknown whether a relationship exists between atherosclerosis and BMD in patients without calcification. It is also unknown if sex plays a role in this relationship.

METHODS

We performed a retrospective cross-sectional study, which included 1459 type 2 diabetes mellitus (T2DM) patients (648 males ≥ 50 years old, and 811 postmenopausal females). They were assigned to three groups: group 1 (patients without carotid plaques and without carotid calcification), group 2 (patients with carotid plaques but without carotid calcification), and group 3 (patients with carotid plaques and with carotid calcification). Clinical characteristics and BMD were compared. The relationship between atherosclerosis and BMD was determined by binary logistic regression analysis. Statistical analysis was performed using SPSS 25.0.

RESULTS

Significant differences were only observed in women. The percentage of osteoporosis was higher in group 3 (43.64%) than in groups 1 (34.82%) and 2 (32.14%) (P = 0.016). Low BMD was found in the lumbar (P = 0.032), hip (P < 0.001), and femoral neck (P < 0.001). The odds ratio for osteoporosis increased significantly in a score-dependent manner in postmenopausal female patients with calcified atherosclerosis, but not in uncalcified patients. In men, no differences or relationships were identified.

CONCLUSION

A negative correlation between carotid atherosclerosis and BMD was found in female T2DM patients with vascular calcification, but not in those without calcification. A similar relationship was not observed in male patients with or without calcification. Thus, the relationship between atherosclerosis and bone mineral density in patients with type 2 diabetes depends on vascular calcifications and sex.

[Expression and distribution of programmed death receptor 1 and T cell immunoglobulin mucin 3 in breast cancer microenvironment and its relationship with clinicopathological features]

Objective: To explore the expression and distribution of programmed death receptor 1 (PD-1) and T-cell immunoglobulin mucin 3 (TIM-3) in breast cancer microenvironment and analyze the their correlation with the clinicopathological features. Methods: The specimens of tumor tissue and adjacent tissues from 30 patients with infiltrative breast cancer who were diagnosed as breast cancer from June 2016 to May 2017 in The First Hospital of Jiaxing were collected, and the specimen were divided into two parts along the center. After embedding and cryosectioning, the expression and distribution of PD-1 and TIM-3 protein in tumor tissues were observed by immunofluorescence staining. Another part of the specimen was cut and digested, and non-continuous density gradient centrifugation was used to extract tumor-infiltrating lymphocytes (TILs), real-time quantitative PCR (qRT-PCR) was used to detect the mRNA expression of PD-1 and TIM-3 in TILs. Meanwhile, the protein expression was determined by Western blotting. The relationship between the expression of PD-1 and TIM-3 and pathological parameters of breast cancer was analyzed with correlation analysis. Results: Immunofluorescence results showed that more PD-1 and TIM-3 positive cells were observed in the tumor tissues compared with the tumor-adjacent tissues. The qRT-PCR showed that the expression of PD-1 and TIM-3 mRNA in TILs were both significantly higher than those in paracancerous tissues (3.09±0.38 vs 1.26±0.23, 3.42±0.31 vs 1.57±0.29, t=4.16, 4.37, both P<0.05). At the protein level, the expression of PD-1 and TIM-3 in tumor tissue lymphocytes(0.66±0.08, 0.80±0.11) was significantly higher than those in cancerous tissues(0.10±0.01, 0.26±0.02) (t=6.79, 4.57, both P<0.05). There were significant differences in the expression of PD-1, TIM-3 mRNA in the TILs between the different tumor histological grades, tumor sizes, lymph node metastasis (t=2.22-2.99, all P<0.05). Correlation analysis showed that there was a significant positive correlation between the expression of PD-1 and TIM-3 in tumor tissues (r=0.616, P<0.01). Conclusions: In the breast cancer microenvironment, PD-1, TIM-3-mediated signaling pathway plays an important role in the occurrence and development of breast cancer, it provides a new basis for the combination therapy of breast cancer.

Network based subcellular proteomics in monocyte membrane revealed novel candidate genes involved in osteoporosis

In this study, label-free-based quantitative subcellular proteomics integrated with network analysis highlighted several candidate genes including P4HB, ITGB1, CD36, and ACTN1 that may be involved in osteoporosis. All of them are predicted as significant membrane proteins with high confidence and enriched in bone-related biological process. The results were further verified in transcriptomic and genomic levels.

INTRODUCTION

Osteoporosis is a metabolic bone disease mainly characterized by low bone mineral density (BMD). As the precursors of osteoclasts, peripheral blood monocytes (PBMs) are supported to be important candidates for identifying genes related to osteoporosis. We performed subcellular proteomics study to identify significant membrane proteins that involved in osteoporosis.

METHODS

To investigate the association between monocytes, membrane proteins, and osteoporosis, we performed label-free quantitative subcellular proteomics in 59 male subjects with discordant BMD levels, with 30 high vs. 29 low BMD subjects. Subsequently, we performed integrated gene enrichment analysis, functional annotation, and pathway and network analysis based on multiple bioinformatics tools.

RESULTS

A total of 1070 membrane proteins were identified and quantified. By comparing the proteins' expression level, we found 36 proteins that were differentially expressed between high and low BMD groups. Protein localization prediction supported the notion that the differentially expressed proteins, P4HB (p = 0.0021), CD36 (p = 0.0104), ACTN1 (p = 0.0381), and ITGB1 (p = 0.0385), are significant membrane proteins. Functional annotation and pathway and network analysis highlighted that P4HB, ITGB1, CD36, and ACTN1 are enriched in osteoporosis-related pathways and terms including "ECM-receptor interaction," "calcium ion binding," "leukocyte transendothelial migration," and "reduction of cytosolic calcium levels." Results from transcriptomic and genomic levels provided additional supporting evidences.

CONCLUSION

Our study strongly supports the significance of the genes P4HB, ITGB1, CD36, and ACTN1 to the etiology of osteoporosis risk.

Tanshinone IIA ameliorates chronic arthritis in mice by modulating neutrophil activities

Rheumatoid arthritis (RA) is a chronic immune inflammatory disease mediated by the influx of immune cells into the synovial joint space. As Tanshinone IIA (TIIA) has potent anti-oxidant and anti-inflammatory activities, we used the adjuvant-induced arthritis (AA) murine model of RA to investigate the impact of TIIA on RA and immune cell activation. The anti-arthritic activity of TIIA was investigated in an adjuvant-induced arthritis model of RA in mice. Myeloperoxidase and neutrophil elastase expression levels were assessed in ankle joints by immunohistochemistry analysis. Immune cell infiltration was evaluated in air pouch experiments. Proinflammatory cytokines expression levels were determined by quantitative real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assays. Neutrophil extracellular traps (NETs) were assessed by immunostaining and confocal microscopy. Treatment with TIIA alleviated cartilage erosion and neutrophil infiltration in the ankle joints of AA mice and reduced proinflammatory cytokine expression levels in sera. TIIA suppressed interleukin-6 and tumour necrosis factor-α expression and release in neutrophils and promoted neutrophil apoptosis. TIIA also inhibited the NET formation of neutrophils. Our findings demonstrated that TIIA can ameliorate RA effectively by targeting neutrophils, indicating that TIIA may act as a potential therapeutic for RA.

Allergic rhinitis and allergy are risk factors for otitis media with effusion: A meta-analysis

OBJECTIVE/HYPOTHESIS

We systematically reviewed the associations between allergic rhinitis or allergy and otitis media with effusion, by reference to published data.

STUDY DESIGN

A meta-analysis of case-controlled studies.

DATA SOURCE

Five databases (Pubmed, Highwire, Medline, Wanfang, and China National Knowledge Infrastructure) were searched for relevant studies in the English language published prior to November 12, 2015.

STUDIES CHOSEN

Studies with clearly defined experimental and control groups, in which the experimental groups had otitis media with effusion together with allergic rhinitis or allergy, were selected.

METHODS

We performed a meta-analysis on data from the identified cross-sectional and case-controlled studies using fixed- or random-effects models (depending on heterogeneity). We used Reviewer Manager 5.3 software to this end.

RESULTS

Seven studies met the inclusion criteria. The prevalence of allergic rhinitis in patients with otitis media with effusion and the control groups differed significantly in three studies (P<0.00001), as did the prevalence of allergy (in six studies; P=0.003).

CONCLUSION

Allergic rhinitis and allergy appear to be risk factors for otitis media with effusion.

The Prevalence, Clinical, and Molecular Characteristics of Congenital Hypothyroidism Caused by DUOX2 Mutations: A Population-Based Cohort Study in Guangzhou

Thyroid dyshormonogenesis (DH) has recently been reported to be more frequently associated with mutations in the dual oxidase 2 (DUOX2) gene. The present study was aimed to investigate the prevalence, clinical, and molecular characteristics of congenital hypothyroidism (CH) caused by DUOX2 mutations in Guangzhou. A population-based cohort of 156 patients with CH was recruited based on neonatal screening among 433 578 newborns born in Guangzhou from 2011 to 2012. Genetic analysis of DUOX2 was performed in 96 patients with suspected thyroid dyshormonogenesis (SDH) by PCR-amplified direct sequencing. Apart from 2 cases without ultrasonographic data, 118 (76.6%) of the 156 patients were classified as SDH and 36 (23.4%) as thyroid dysgenesis (TD) according to thyroid ultrasound at diagnosis. Genetic analysis revealed 23 different variants in 60 unrelated individuals (60/96, 62.5%), including 13 novel variants that were absent from HGMD, dbSNP databases, and the 50 normal controls. The novel missense variants were predicted to be pathogenic by SIFT and PolyPhen-2. The p.K530X was the most common mutation. Ninety-three percent of mutant alleles occurred in exons 5, 6, 9, 14, 17, 20, 25, 27, and 28. There were no significant differences in phenotypes between biallelic and monoallelic variants cases or between with-DUOX2 and non-DUOX2 variants cases. Most patients with DUOX2 defects (78.2%) were transient CH. In conclusion, the prevalence of DUOX2 pathogenic variants was high (62.5%) in this cohort. Thirteen novel probably pathologic variants were reported. The p.K530X was the most common mutation in the Chinese population. There was no correlation between DUOX2 genotypes and clinical phenotypes.

Hyperthyroidism caused by acquired immune deficiency syndrome

BACKGROUND

Acquired immune deficiency syndrome (AIDS) is an immune deficiency disease. The etiology of hyperthyroidism, which can also be immune-related, is usually divided into six classical categories, including hypophyseal, hypothalamic, thyroid, neoplastic, autoimmune and inflammatory hyperthyroidism. Hyperthyroidism is a rare complication of highly active antimicrobial therapy (HAART) for human immunodeficiency virus (HIV). Hyperthyroidism caused directly by AIDS has not been previously reported.

PATIENT FINDINGS

A 29-year-old man who complained of dyspnea and asthenia for 1 month, recurrent fever for more than 20 days, and breathlessness for 1 week was admitted to our hospital. The thyroid function test showed that the level of free thyroxine (FT4) was higher than normal and that the level of thyroid-stimulating hormone (TSH) was below normal. He was diagnosed with hyperthyroidism. Additional investigations revealed a low serum albumin level and chest infection, along with diffuse lung fibrosis. Within 1 month, he experienced significant weight loss, no hand tremors, intolerance of heat, and perspiration proneness. We recommended an HIV examination; subsequently, AIDS was diagnosed based on the laboratory parameters.

SUMMARY

This is the first reported case of hyperthyroidism caused by AIDS.

CONCLUSIONS

AIDS may cause hyperthyroidism by immunization regulation with complex, atypical, and easily ignored symptoms. Although hyperthyroidism is rare in patients with AIDS, clinicians should be aware of this potential interaction and should carefully monitor thyroid function in HIV-positive patients.

An antiapoptotic Bcl-2 family protein index predicts the response of leukaemic cells to the pan-Bcl-2 inhibitor S1

BACKGROUND

Bcl-2-like members have been found to be inherently overexpressed in many types of haematologic malignancies. The small-molecule S1 is a BH3 mimetic and a triple inhibitor of Bcl-2, Mcl-1 and Bcl-XL.

METHODS

The lethal dose 50 (LD(50)) values of S1 in five leukaemic cell lines and 41 newly diagnosed leukaemia samples were tested. The levels of Bcl-2 family members and phosphorylated Bcl-2 were semiquantitatively measured by western blotting. The interactions between Bcl-2 family members were tested by co-immunoprecipitation. The correlation between the LD(50) and expression levels of Bcl-2 family members, alone or in combination, was analysed.

RESULTS

S1 exhibited variable sensitivity with LD(50) values ranging >2 logs in both established and primary leukaemic cells. The ratio of pBcl-2/(Bcl-2+Mcl-1) could predict the S1 response. Furthermore, we demonstrated that pBcl-2 antagonised S1 by sequestering the Bak and Bim proteins that were released from Mcl-1, andpBcl-2/Bak, pBcl-2/Bax and pBcl-2/Bim complexes cannot be disrupted by S1.

CONCLUSION

A predictive index was obtained for the novel BH3 mimetic S1. The shift of proapoptotic proteins from being complexed with Mcl-1 to being complexed with pBcl-2 was revealed for the first time, which is the mechanism underlying the index value described herein.

Identifying New Sources of Resistance to Eyespot of Wheat in Aegilops longissima

Eyespot, caused by Oculimacula yallundae and O. acuformis, is an economically important disease of wheat. Currently, two eyespot resistance genes, Pch1 and Pch2, are used in wheat breeding programs but neither provides complete control or prevents yield loss. Aegilops longissima is a distant relative of wheat and proven donor of genes useful for wheat improvement, including disease resistance. Forty A. longissima accessions and 83 A. longissima chromosome addition or substitution lines were evaluated for resistance to eyespot. Among the 40 accessions tested, 43% were resistant to O. yallundae, 48% were resistant to O. acuformis, and 33% were resistant to both. Addition or substitution lines containing chromosomes 1S¹, 2S¹, 5S¹, and 7S¹, and a 4S¹7S¹ translocation were resistant to O. yallundae. Chromosomes 1S¹, 2S¹, 4S¹, and 5S¹ contributed to resistance to O. acuformis more than others. Chromosomes 1S¹, 2S¹, 5S¹, and 7S¹ provided resistance to both pathogens. This is the first report of eyespot resistance in A. longissima. These results provide evidence that genetic control of eyespot resistance is present on multiple chromosomes of the S¹ genome. This research demonstrates that A. longissima is a potential new source of eyespot resistance genes that could broaden the genetic diversity for wheat improvement.

[Endoscopic orbital decompression for thyroid-associated ophthalmopathy]

OBJECTIVE

To evaluate the therapeutic results of endoscopic orbital decompression for thyroid-associated ophthalmopathy.

METHOD

The records of nine patients (twelve orbits) received endoscopic orbital decompression for thyroid-associated ophthalmopathy were analyzed for changes in visual acuity, intraocular pressure, proptosis, corneal ulceration and movement. The follow-ups ranged from two months to thirty-six months.

RESULT

Twelve orbits (100%) had improvement in visual acuity (range 0.1-0.7). Ten orbits (83.3%) decreased in intraocular pressure (range 0.2-21.4 mm Hg). Eight orbits (66.70%) decreased in proptosis (one-five mm). The orbit with corneal ulcer was healed after decompression. Diplopia was cured in one of four patients.

CONCLUSION

Endoscopic orbital decompression is a safe and effective procedure for the treatment of thyroid-associated ophthalmopathy.

MiR-148a promotes apoptosis by targeting Bcl-2 in colorectal cancer

Apoptosis has a vital role in maintaining tissue homeostasis, and dysregulation of the apoptotic pathway is now widely recognized as a key step in tumourigenesis. Increasingly, evidence has demonstrated that microRNA (miRNA) can exert various biological functions in tumours by targeting oncogenes or tumour suppressors. Nevertheless, the role of miRNA in apoptosis remains unclear. Here we show that ectopical expression of miR-148a can induce apoptosis in colorectal cancer cells. In addition, MYB can inhibit miR-148a by directly acting on the transcription factor binding site in miR-148a gene and miR-148a can posttranscriptionally silence Bcl-2. Subsequently, the intrinsic apoptosis pathway is activated by releasing cytochrome c, cleaving caspase 9, caspase 3 and PARP, which eventually induce cancer-cell apoptosis. These findings are part of a hitherto undocumented apoptotic regulatory pathway in which a pleiotropic transcription factor controls the expression of a miRNA and the miRNA inhibits the target, leading to activation of an intrinsic mitochondrial pathway and tumour apoptosis.

Ocular complications of heart transplantation in a Chinese population

The purpose of this study was to investigate ocular complications among a group of patients on long-term, high-dose immunosuppression and corticosteroids for the maintenance of orthotopic heart transplants. Additionally, we provided information pertinent for the early diagnosis and treatment of eye diseases. In this study, we retrospectively assessed the clinical data of 138 patients with orthotopic heart transplantations from May 2000 to October 2005, including assessment of ophthalmic symptoms and signs, as well as the general condition, treatment, and prognosis. Of 138 transplant recipients examined (276 eyes), 47 eyes (17.0%) showed ocular surface diseases. Sixty-four (23.2%) had a posterior subcapsular cataract, and 16 (5.8%) corticosteroid glaucoma. Fifteen (5.6%) had ocular fundus diseases. Various ocular complications related to immunosuppression and corticosteroids appear among heart transplant patients. Cardiac surgeons and ophthalmologists must closely evaluate ocular symptoms in the posttransplantation period.

Epimedium-derived phytoestrogen exert beneficial effect on preventing steroid-associated osteonecrosis in rabbits with inhibition of both thrombosis and lipid-deposition

OBJECTIVES

This study tested the effect of Epimedium-derived phytoestrogen (PE) on preventing steroid-associated osteonecrosis (ON) in rabbit model.

METHODS

Thirty 28-week-old male New-Zealand white rabbits were divided into control group (CON; n=14) and PE group (PE; n=16; 5 mg/kg body weight/day) after receiving an established inductive protocol for inducing steroid-associated ON. Before and after inductive protocol, Dynamic-MRI was employed on bilateral femora for local intra-osseous perfusion, blood samples were examined for coagulation, fibrinolysis and lipid-transportation, and marrow samples were quantified for adipogenesis-gene mRNA expression. Six weeks later, bilateral femora were dissected for Micro-CT-based micro-angiography, and then ON lesion, intravascular thrombosis and extravascular fat-cell-size were examined histopathologically.

RESULTS

The incidence of ON in the PE group (31%) was significantly lower than that in the CON group (93%). Compared to the CON group, local intra-osseous perfusion was maintained in the PE group. Blocked trunk vessels were seldom found in micro-angiography of the PE-treated rabbits. Thrombosis incidence and fat-cell-size were both significantly lower in the PE group than those in the CON group. During the early period after induction, indicator of coagulation, fibrinolysis, lipid-transportation and adipogenesis-gene expression were found with significantly changing pattern in the PE group compared to the CON group.

CONCLUSION

PE was able to exert beneficial effect on preventing steroid-associated ON in rabbits with inhibition of both thrombosis and lipid deposition.

Expression of Renal Transforming Growth Factor-β and Its Receptors in a Rat Model of Chronic Cyclosporine-Induced Nephropathy

OBJECTIVE

We sought to detect expression of transforming growth factor-beta 1 (TGF-beta1) as well as its receptors type I (TRI) and type II (TRII) in rat kidneys during chronic cyclosporine (CsA)-induced nephropathy.

METHODS

Twenty four rats were randomly divided into three experimental groups: group 1; NSD (control, n = 8) were administered a normal sodium diet, group 2; LSD (n = 8) were administered a low sodium diet, group 3; CsA (n = 8) were sodium-depleted rats administered Neoral by gastric gavage in a model of chronic CsA-induced nephropathy. TGF-beta1, TRI, and TRII proteins, as well as TRI and TRII mRNAs were measured in the CsA-treated rat kidneys by immunohistochemistry and in situ hybridization, respectively. Semiquantitative results were shown by image analysis.

RESULTS

The expression of TGF-beta1, TRI, TRII, TRI mRNA, and TRII mRNA were all increased in CsA-treated rat kidneys, compared with NSD or LSD (P < .05).

CONCLUSION

Our study showed that the ligand of TGF-beta1 and its receptors TRI, TRII were all up-regulated. It may be important to inhibit the expression of TGF-beta1 or its receptors in patients who suffer from chronic CsA-induced nephropathy.

Comparison of Expression of TGF-β1, its Receptors TGFβ1R-I and TGFβ1R-II in Rat Kidneys During Chronic Nephropathy Induced by Cyclosporine and Tacrolimus

OBJECTIVE

Chronic rejection is a major cause of graft dysfunction after kidney transplantation. Long-term treatment with cyclosporine (CsA) or tacrolimus (FK506) results in chronic nephrotoxicity. Transforming growth factor-beta1 (TGFbeta1) and its receptors type I (TR-I) and type II (TR-II) have been known to contribute to this side effect. The expression of TGF-beta1, TR-I, and TR-II in rat kidneys has not been compared during chronic nephropathy induced by CsA or FK506.

METHODS

Rat models of chronic CsA- or FK506-induced nephropathy were established using Sandimun Neoral or Prograf administration. The kidneys were dissected and TGF-beta1, TR-I, and TR-II proteins and TR-I and TR-II mRNAs measured by immunohistochemistry and in situ hybridization, respectively, to compare the results of the two groups.

RESULTS

The functional and morphologic studies showed that in the rats the nephrotoxic effects of FK506 were not as significant as those of CsA. The results of immunohistochemistry and in situ hybridization showed that the expression of renal TGFbeta1, TR I, TR-II proteins and TR and TR II mRNA in the FK506 group were lower than those in the CsA groups.

CONCLUSION

These results showed that both FK506 and CSA display nephrotoxicity, but that the nephrotoxicity of FK506 was less than that of CsA in chronic nephropathy.

Clustered gases as a medium for efficient plasma waveguide generation

Clustered gas jets are shown to be an efficient means for plasma waveguide generation, for both femtosecond and picosecond generation pulses. These waveguides enable significantly lower on-axis plasma density (less than 10(18) cm(-3)) than in conventional hydrodynamic plasma waveguides generated in unclustered gases. Using femtosecond pump pulses, self-guided propagation and strong absorption (more than 70%) are used to produce long centimetre scale channels in an argon cluster jet, and a subsequent intense pulse is coupled into the guide with 50% efficiency and guided at above 10(17)W cm(-2) intensity over 40 Rayleigh lengths. We also demonstrate efficient generation of waveguides using 100 ps axicon-generated Bessel-beam pump pulses. Despite the expected sub-picosecond cluster disassembly time, we observe long pulse absorption efficiencies up to a maximum of 35%. Simulations show that in the far leading edge of the long laser pulse, the volume of heated clusters evolves to a locally uniform and cool plasma already near ionization saturation, which is then efficiently heated by the remainder of the pulse.

HOXB13 is downregulated in colorectal cancer to confer TCF4-mediated transactivation

Mutations in the Wnt signalling cascade are believed to cause aberrant proliferation of colorectal cells through T-cell factor-4 (TCF4) and its downstream growth-modulating factors. HOXB13 is exclusively expressed in prostate and colorectum. In prostate cancers, HOXB13 negatively regulates β-catenin/TCF4-mediated transactivation and subsequently inhibits cell growth. To study the role of HOXB13 in colorectal tumorigenesis, we evaluated the expression of HOXB13 in 53 colorectal tumours originated from the distal left colon to rectum with their matching normal tissues using quantitative RT–PCR analysis. Expression of HOXB13 is either lost or diminished in 26 out of 42 valid tumours (62%), while expression of TCF4 RNA is not correlated with HOXB13 expression. TCF4 promoter analysis showed that HOXB13 does not regulate TCF4 at the transcriptional level. However, HOXB13 downregulated the expression of TCF4 and its target gene, c-myc, at the protein level and consequently inhibited β-catenin/TCF-mediated signalling. Functionally, forced expression of HOXB13 drove colorectal cancer (CRC) cells into growth suppression. This is the first description of the downregulation of HOXB13 in CRC and its mechanism of action is mediated through the regulation of TCF4 protein stability. Our results suggest that loss of HOXB13 may be an important event for colorectal cell transformation, considering that over 90% of colorectal tumours retain mutations in the APC/β-catenin pathway.

Plasma waveguides efficiently generated by Bessel beams in elongated cluster gas jets

We demonstrate the efficient generation of plasma waveguides in elongated cluster gas jets using 100 ps axicon-generated Bessel beam pump pulses. The plasma waveguide space and time evolution is measured using picosecond interferometry. Small radius waveguides with central densities as low as approximately 10(18) cm(-3) can be generated with this technique. Despite the expected subpicosecond cluster disassembly time, we observe long pulse absorption efficiencies that can be more than a factor of 10 greater than in unclustered gas targets of the same volume average atomic density. The maximum long pulse absorption observed in cluster jets under our range of conditions was 35%. The explanation for the enhanced absorption is that in the far-leading edge of the laser pulse, the volume of heated clusters evolves to a locally uniform and cool plasma already near ionization saturation, which is then heated by the remainder of the pulse. From this perspective, the use of clustered gases is equivalent to a supercharged preionization scheme for long duration laser pulses.

Phosphatidylinositol 3-kinase mediates proliferative signals in intestinal epithelial cells

BACKGROUND AND AIMS

Determination of intracellular signalling pathways that mediate intestinal epithelial proliferation is fundamental to the understanding of the integrity and function of the intestinal tract under normal and diseased conditions. The phosphoinositide 3-kinase (PI3K)/Akt pathway transduces signals initiated by growth factors and is involved in cell proliferation and differentiation. In this study, we assessed the role of PI3K/Akt in transduction of proliferative signals in intestinal epithelial cells.

METHODS

A rat intestinal epithelial (RIE) cell line and human colorectal cancer HCA-7 and LS-174 cell lines served as in vitro models. The Balb/cJ mouse was the in vivo model.

RESULTS

PI3K activation was critical for G1 cell cycle progression of intestinal epithelial cells. Ectopic expression of either active p110alpha or Akt-1 increased RIE cell proliferation. In vivo experiments demonstrated that PI3K activation was closely associated with the proliferative activity of intestinal mucosa. Treatment of mice with PI3K inhibitors blocked induction of PI3K activity and attenuated intestinal mucosal proliferation associated with oral intake. Epidermal growth factor and transforming growth factor alpha stimulated PI3K activation which was required for growth factor induced expression of cyclin D1.

CONCLUSIONS

The PI3K/Akt pathway transduces mitogenic signals from growth factor receptors to the cell cycle machinery and plays a critical role in regulation of intestinal epithelial proliferation.

[A pilot study on malaria control by using a new strategy of combining strengthening infection source treatment and health education in mountainous areas of Hainan province]

AIM

To explore a new malaria control strategy that fits current epiodemiological condition and coincides with modern medicine model and the principle of cost-benefit.

METHODS

The new strategy highlights the risk villages and risk population as the focal point and integrates health education with behavioral intervention. The main anti-malaria measures consists of carrying out health education in risk villages, giving mass drug administrations in risk population staying overnight in the mountain, following up malaria cases for implementing radical cure, but without using traditional residual spraying or impregnating bednets with insecticides.

RESULTS

After having adopted the new strategy and taken the control measures, the people's knowledge about malaria increased to a higher level and the indices of malaria reduced to a lower level. The rate of bednet-using in the population was increased from 26.8% to 72.6%. The annual parasite incidence (API) of malaria was declined from 3.5% in 1994 to 1.1% in 1996 and 0.8% in 1997, and the API of falciparum malaria was declined from 1.0% to 0.3% and 0.3% respectively in the townships at the same time. The parasite rate(PR) of malaria was declined from 7.2% in May, 1995 to 2.1% in November, 1996 and 1.2% in October, 1997 and the PR of falciparum malaria was declined from 1.2% in May, 1995 to 0.1% in October, 1997. The proportion of villages without malaria cases was increased from 18.6% in 1994 to 54.2% in 1997, and the number of risk villages with a malaria incidence above 5% was reduced from 14 to 2 at the same time. The ratio of cost/benefit was 1:2.4 in 1995-1996 and 1:4.4 in 1997, showing a better economic benefit.

CONCLUSION

The expectant result has been obtained, thereby providing new experience for the malaria control in the mountainous areas of Hainan Province.

Tracking brain volume changes in C57BL/6J and ApoE-deficient mice in a model of neurodegeneration: a 5-week longitudinal micro-MRI study

Magnetic resonance imaging (MRI)-based volume measurements of brain structures are useful indicators of pending cognitive decline in humans suffering from neurodegenerative diseases. Transgenic mouse models that mimic the clinical conditions of these disorders have been developed. Noninvasive methods that can follow progression and regression of relevant pathology in these mice are therefore in great demand. In this study we tested whether high-resolution MRI (micro-MRI) in a mouse model of neurodegeneration (cerebral ischemia) could reliably track development of brain atrophy. We first established that diffusion imaging at a spatial resolution of 1.6 x 10(-3) mm(3) allowed superior visualization of forebrain, ventricles, and dorsal hippocampus in the mouse brain compared to either T2*- or T1-weighted MR imaging. Using this predetermined protocol we subsequently scanned C56BL/6J (C57) and ApoE-deficient (ApoE(-/-)) mice before and after ischemia. Four groups were studied: C57/sham (n = 9), ApoE(-/-)/sham (n = 9), C57/ischemia (n = 9), and ApoE(-/-)/ischemia (n = 11). All mice received a baseline 3D diffusion scan. One week later C57/ischemia and ApoE(-/-)/ischemia mice were exposed to 10 min of ischemia and scanned again on the 3rd and 30th postischemic day. The C57/sham and ApoE(-/-)/sham mice served as controls and were scanned at corresponding time points. Diffusion images of ApoE(-/-)/ischemia mice on the 3rd postischemic day revealed multiple localized high signal intensity areas. An increase in ventricle and a decrease in dorsal hippocampal volumes (which included the associated cortex laterally) at 30 days confirmed brain atrophy in C57 mice after ischemia. Excessive mortality of ApoE(-/-)/ischemia mice restricted statistical analysis, but ventricle enlargement postischemia was demonstrated. Our results show that volume changes in the brain of a 30-g mouse can be tracked by micro-MRI in a model of neurodegeneration. Clearly the ability to follow progression of pathology in mice will greatly aid our understanding of neurodegenerative diseases and facilitate the many possibilities to intervene pharmacologically.

A cyclooxygenase-2 inhibitor (SC-58125) blocks growth of established human colon cancer xenografts

Selective COX-2 inhibitors reduce adenoma formation and cancer progression in rodent models of colorectal cancer. To assess the therapeutic activity of selective COX-2 inhibitors, we tested the effect of SC-58125 treatment on the growth of human colon carcinoma cells in nude mice. Delaying treatment by 2, 4, or 7 weeks following implantation of the carcinoma cells resulted in a significant inhibition of tumor growth. Furthermore, short-term (48 hours) treatment with SC-58125 was sufficient to attenuate tumor growth for up to 15 days. SC-58125 treatment did not alter the rate at which cells underwent apoptosis, but did result in a delayed progression through the cell cycle at the G(2)/M transition. Accordingly, p34(cdc2) protein levels and activity were decreased following SC-58125 treatment. We conclude that SC-58125 primarily exerts a cytostatic effect in vivo, which is likely to be mediated through inhibition of progression through the G(2)/M phase of the cell cycle.

Neuroprotection from delayed postischemic administration of a metalloporphyrin catalytic antioxidant

Reactive oxygen species contribute to ischemic brain injury. This study examined whether the porphyrin catalytic antioxidant manganese (III) meso-tetrakis (N-ethylpyridinium-2-yl)porphyrin (MnTE-2-PyP(5+)) reduces oxidative stress and improves outcome from experimental cerebral ischemia. Rats that were subjected to 90 min focal ischemia and 7 d recovery were given MnTE-2-PyP(5+) (or vehicle) intracerebroventricularly 60 min before ischemia, or 5 or 90 min or 6 or 12 hr after reperfusion. Biomarkers of brain oxidative stress were measured at 4 hr after postischemic treatment (5 min or 6 hr). MnTE-2-PyP(5+), given 60 min before ischemia, improved neurologic scores and reduced total infarct size by 70%. MnTE-2-PyP(5+), given 5 or 90 min after reperfusion, reduced infarct size by 70-77% and had no effect on temperature. MnTE-2-PyP(5+) treatment 6 hr after ischemia reduced total infarct volume by 54% (vehicle, 131 +/- 60 mm(3); MnTE-2-PyP(5+), 300 ng, 60 +/- 68 mm(3)). Protection was observed in both cortex and caudoputamen, and neurologic scores were improved. No MnTE-2-PyP(5+) effect was observed if it was given 12 hr after ischemia. MnTE-2-PyP(5+) prevented mitochondrial aconitase inactivation and reduced 8-hydroxy-2'-deoxyguanosine formation when it was given 5 min or 6 hr after ischemia. In mice, MnTE-2-PyP(5+) reduced infarct size and improved neurologic scores when it was given intravenously 5 min after ischemia. There was no effect of 150 or 300 ng of MnTE-2-PyP(5+) pretreatment on selective neuronal necrosis resulting from 10 min forebrain ischemia and 5 d recovery in rats. Administration of a metalloporphyrin catalytic antioxidant had marked neuroprotective effects against focal ischemic insults when it was given up to 6 hr after ischemia. This was associated with decreased postischemic superoxide-mediated oxidative stress.

Transforming growth factor-beta1 promotes invasiveness after cellular transformation with activated Ras in intestinal epithelial cells

Invasion is a defining event in carcinoma progression. In general, invasive carcinoma is characterized by an epithelial-fibroblastoid conversion associated with loss of cell-cell adhesion receptors such as E-cadherin and beta-catenin. We report here that TGF-beta1 promotes the invasiveness by modulating the alterations of cellular plasticity including a loss of cell-cell contact in Ras-transformed epithelial cells. In order to examine the role of TGF-beta1 in the Ras-induced responses, intestinal epithelial cells expressing a conditionally activated Ha-Ras(Val12) (RIE-iRas cells) were used in this study. Induced expression of activated Ha-Ras(Val12) caused morphologic transformation of the RIE-iRas cells with an increase in vimentin expression and a decrease of E-cadherin levels. There was also redistribution of beta-catenin from the cytoplasm to the nucleus after the induction of Ras. TGF-beta1 treatment enhanced both the decrease in E-cadherin levels and the redistribution of beta-catenin. Interestingly, the activation of Ras markedly decreased the level of TGF-beta receptor type II (TbetaRII) in RIE-iRas cells. However, the expression of plasminogen activator inhibitor-1, which is known to be transcriptionally induced by TGF-beta1, was strongly induced by TGF-beta1 despite the marked downregulation of TbetaRII. The induction of Ha-Ras(Val12) markedly increased the invasiveness in RIE-iRas cells, as evaluated by a collagen type I-coated Boyden-chamber assay, and the Ras-mediated invasiveness was significantly enhanced by TGF-beta1 treatment. Expression of a dominant-negative form of TbetaRII in the RIE-iRas cells abrogated both growth-inhibitory and invasion responses to TGF-beta1. Collectively, these results suggest that TGF-beta1 and oncogenic Ras collaborate in promoting cellular invasiveness in intestinal epithelial cells. The enhancement of invasiveness was correlated with decreased E-cadherin levels and subcellular distribution of beta-catenin. The enhancement of oncogenic Ras-mediated cell transformation by TGF-beta1 occurs via TbetaRII.

Targeting cyclooxygenase 2 and HER-2/neu pathways inhibits colorectal carcinoma growth

BACKGROUND & AIMS

The cyclooxygenase 2 (COX-2) and ErbB/HER pathways are important modulators of cancer cell growth. We sought to determine the effects of treatment with a specific COX-2 inhibitor and/or a monoclonal antibody against the ErbB receptor subtype HER-2/neu on carcinoma cell growth.

METHODS

A cell-proliferation assay was used to determine the response of HCA-7 cells to the HER-3/HER-4 ligand heregulin beta-1 (HRGbeta-1). Both in vitro and in vivo assays were used to determine the effects of the selective COX-2 inhibitor, celecoxib, and/or an anti-HER-2/neu monoclonal antibody (either Herceptin [Genetech Inc., S. San Francisco, CA] or 2C4) on cell growth.

RESULTS

HCA-7 cells express HER-2/neu messenger RNA and protein, and exposure of these cells to HRGbeta-1 results in a significant stimulation of cell growth. Celecoxib or Herceptin inhibits HCA-7 cell growth in vitro and in vivo. Combination therapy with celecoxib plus Herceptin or celecoxib plus 2C4 resulted in additive effects that resulted in almost complete inhibition of tumor growth.

CONCLUSIONS

Combined treatment with COX-2 and HER-2/neu inhibitors more effectively reduces colorectal carcinoma growth than either agent alone. Therefore, targeting of both the COX-2 and ErbB signaling pathways may represent a novel approach for the treatment and/or prevention of colorectal cancer in humans.

Extracellular superoxide dismutase overexpression improves behavioral outcome from closed head injury in the mouse

Oxidative stress is known to play an important role in the response of brain to traumatic insults. We tested the hypothesis that increased extracellular superoxide dismutase (EC-SOD) expression can reduce injury in a mouse model of closed head injury. Neurologic, cognitive, and histologic outcomes were compared between transgenic mice exhibiting a fivefold increase in EC-SOD activity and wild-type littermate controls. Severe or moderate transcranial impact was induced in anesthetized and physiologically controlled animals. After severe impact, transgenic mice had better neurological outcome at 24 hr postinjury (p = 0.038). Brain water content was increased, but there was no difference between groups. Moderate impact resulted in predominantly mild neurologic deficits in both groups at both 24 hr and 14 days postinjury. Morris water maze performance, testing cognitive function at 14-17 days after trauma, was better in EC-SOD overexpressors (p = 0.018). No differences were observed between groups for histologic damage in hippocampal CA1 and CA3. We conclude that EC-SOD has a beneficial effect on behavioral outcome after both severe and moderate closed head injury in mice. Because EC-SOD is believed to be predominantly located in the extracellular space, these data implicate an adverse effect of extracellular superoxide anion on outcome from closed head injury.

Prostaglandin E2 increases growth and motility of colorectal carcinoma cells

Chronic use of nonsteroidal anti-inflammatory drugs results in a significant reduction of risk and mortality from colorectal cancer in humans. All of the mechanism(s) by which nonsteroidal anti-inflammatory drugs exert their protective effects are not completely understood, but they are known to inhibit cyclooxygenase activity. The cyclooxygenase enzymes catalyze a key reaction in the conversion of arachidonic acid to prostaglandins, such as prostaglandin E(2) (PGE(2)). Here we demonstrate that PGE(2) treatment of LS-174 human colorectal carcinoma cells leads to increased motility and changes in cell shape. The prostaglandin EP(4) receptor signaling pathway appears to play a role in transducing signals which regulate these effects. PGE(2) treatment results in an activation of phosphatidylinositol 3-kinase/protein kinase B pathway that is required for the PGE(2)-induced changes in carcinoma cell motility and colony morphology. Our results suggest that PGE(2) might enhance the invasive potential of colorectal carcinoma cells via activation of major intracellular signal transduction pathways not previously reported to be regulated by prostaglandins.

Akt/PKB activity is required for Ha-Ras-mediated transformation of intestinal epithelial cells

Phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/Akt) is thought to serve as an oncogenic signaling pathway which can be activated by Ras. The role of PI3K/Akt in Ras-mediated transformation of intestinal epithelial cells is currently not clear. Here we demonstrate that inducible expression of oncogenic Ha-Ras results in activation of PKB/Akt in rat intestinal epithelial cells (RIE-iHa-Ras), which was blocked by treatment with inhibitors of PI3K activity. The PI3K inhibitor, LY-294002, partially reversed the morphological transformation induced by Ha-Ras and resulted in a modest stimulation of apoptosis. The most pronounced phenotypic alteration following inhibition of PI3K was induction of G(1) phase cell cycle arrest. LY-294002 blocked the Ha-Ras-induced expression of cyclin D1, cyclin-dependent kinase (CDK) 2, and increased the levels of p27(kip). Both LY-294002 and wortmannin significantly reduced anchorage-independent growth of RIE-iHa-Ras cells. Forced expression of both the constitutively active forms of Raf (DeltaRaf-22W or Raf BXB) and Akt (Akt-myr) resulted in transformation of RIE cells that was not achieved by transfection with either the Raf mutant construct or Akt-myr alone. These findings delineate an important role for PI3K/Akt in Ras-mediated transformation of intestinal epithelial cells.

K-Ras-mediated increase in cyclooxygenase 2 mRNA stability involves activation of the protein kinase B1

Cyclooxygenase (COX) 2 expression is regulated via the Ras signaling pathway, and induction of mutated Ras rapidly increases COX-2 levels in intestinal epithelial cells. Protein kinase B (Akt/PKB) is an important effector of Ras signaling and a critical component of Ras-mediated transformation. Here we investigate the role of Akt/PKB in K-Ras-mediated induction of COX-2. Rat intestinal epithelial cells (IEC-6) were transfected with an inducible K-RasVal12 cDNA (IEC-iK-Ras cells). Addition of 5 mM isopropyl-1-thio-beta-D-galactopyranoside induced the expression of K-RasVal12, followed by increased activity of extracellular signal-regulated kinase and Akt/PKB. COX-2 levels were dramatically increased after induction of K-RasVal12. Inhibition of MAPK/ERK kinase activity by PD 98059 completely blocked the K-Ras-mediated induction of COX-2, whereas inhibition of PI3K/Akt/PKB activity with LY 294002 or by expressing a dominant negative Akt (Akt-K179M) partially blocked the induction of COX-2 by K-Ras. Transient transfection of cells with phosphatidylinositol 3-kinase and Akt expression vectors revealed that PI3/Akt/PKB activity predominantly regulates the stability of COX-2 mRNA. Thus, Akt/PKB activity is involved in K-Ras-induced expression of COX-2 and stabilization of COX-2 mRNA largely depends on the activation of Akt/PKB.

Primary structure of human matrilin-2, chromosome location of the MATN2 gene and conservation of an AT-AC intron in matrilin genes

We isolated full-length cDNA clones for human matrilin-2, an oligomeric protein, which forms filamentous networks in the extracellular matrices of various tissues. The human matrilin-2 precursor is encoded by a 4.0-kb mRNA, it consists of 956 amino acids and shows 93% similarity to the mouse protein. Out of the two von Willebrand factor type A-like domains, the 10 epidermal growth factor-type modules, one unique sequence and the oligomerization module, the first A domain is the most conserved. RT-PCR demonstrated wide expression of the gene in human cell lines of fibroblastic or epithelial origin. Alternative splicing affected only 19 amino acids in a 75-moiety-long segment, unique to matrilin-2. Isolation and analysis of the 3' end of the gene revealed that the reason for alternative splicing is alternative 3' splice site selection. Further, we identified in the human matrilin-2 gene a U12 type AT-AC intron between the last two exons encoding the oligomerization domain. We mapped the matrilin-2 gene (MATN2) by fluorescence in situ hybridization at chromosome position 8q22.

Generation and phenotype of mice harboring a nonsense mutation in the V2 vasopressin receptor gene

The V2 vasopressin receptor (V2R) plays a key role in the maintenance of a normal body water balance. To generate an in vivo model that allows the physiological and molecular analysis of the role of V2Rs in kidney function, we have created mouse lines that lack functional V2Rs by using targeted mutagenesis in mouse embryonic stem cells. Specifically, we introduced a nonsense mutation known to cause X-linked nephrogenic diabetes insipidus (XNDI) in humans (Glu242stop) into the mouse genome. V2R-deficient hemizygous male pups showed a decrease in basal urine osmolalities and were unable to concentrate their urine. These pups also exhibited an enlargement of renal pelvic space, failed to thrive, and died within the first week after birth due to hypernatremic dehydration. Interestingly, female mice heterozygous for the V2R mutation showed normal growth but displayed an XNDI-like phenotype, characterized by reduced urine concentrating ability of the kidney, polyuria, and polydipsia. Western blot analysis and immunoelectron microscopic studies showed that the loss of functional V2Rs had no significant effect on the basal expression levels of aquaporin-2 and the bumetanide-sensitive Na-K-2Cl cotransporter (BSC-1). The V2R mutant mice described here should serve as highly useful tools for the development of novel therapeutic strategies for the treatment of XNDI.

Celecoxib prevents tumor growth in vivo without toxicity to normal gut: lack of correlation between in vitro and in vivo models

Nonsteroidal anti-inflammatory drugs have potential for use in the prevention and/or treatment of colorectal cancer. We have studied the cytotoxic effect of a specific COX-2 inhibitor, celecoxib, against LLC, HCA-7, and HCT-15 cells grown in cell culture and have compared these results with its effect on HCA-7 cells grown as xenografts in nude mice. "High-dose" celecoxib (>20 microM) reduced the viability of all three cell lines in vitro as measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometric analysis demonstrated that this loss of viability was attributable to the induction of apoptosis. Significantly, concentrations of the drug <10 microM had no effect on cell viability in vitro. The cytotoxic effects of high-dose celecoxib were independent of COX-2 inhibition because similar effects were observed in cox-2 (+/+), cox-2 (+/-) and cox-2 (-/-) fibroblasts. A plasma concentration of 2.3+/-0.7 microM was achieved when celecoxib (1250 mg/kg of chow) was fed to animals ad libitum. Despite a lack of toxicity at 2-3 microM celecoxib in vitro, there was attenuation of HCA-7 xenograft growth in vivo. Celecoxib had no effect on apoptosis, cell division, or the epithelial architecture of the normal gut in treated mice. These results support the need for additional clinical evaluation of celecoxib for treatment and/or prevention of colorectal cancer in humans.