Intermittent exotropia surgery in children: long term outcome regarding changes in binocular alignment. A study of 666 cases

PURPOSE

To review and determine the long term outcome of surgery for intermittent exotropia in children.

CASES

A total of 666 cases were reviewed. They were 15 years old or younger and underwent surgery for intermittent exotropia during the preceding 22 years. Bilateral recession of the lateral rectus muscles was performed in 349 cases. Unilateral recession of the lateral rectus and resection of the medial rectus muscles was performed in 298 cases. One and four muscle procedures were performed in 19 cases. The outcome was evaluated at 1 month and 4 years after surgery.

RESULTS

Orthotropia or mini-microtropia was achieved in 401 patients (60.2%) one month after surgery. Bilateral recession of the lateral rectus muscles was more effective than unilateral recession- resection. Out of these 401 patients, half, 199 patients (49.6%) showed orthotropia or mini-microtropia 4 years after surgery while the other half, 202 (50.4%), became exotropic. Bilateral recession of the lateral rectus muscles was also more effective in producing orthotropia or mini-microtropia on a long term basis than unilateral recession-resection. The rate of orthotropia or mini- microtropia was higher when the patients were operated before 3 years and after 11 years of age.

CONCLUSIONS

There was a strong tendency for intermittent exotropia to recurr and drift into permanent exotropia during 4 or more years following surgery. It is advocated to aim at orthotropia during the immediate post- surgical period and to avoid overcorrection. Early surgery is not necessary when the patient is over 4 years of age. Bilateral lateral rectus recession is the preferred surgical procedure.

The mechanisms by which both heterozygous peroxisome proliferator-activated receptor gamma (PPARgamma) deficiency and PPARgamma agonist improve insulin resistance

Peroxisome proliferator-activated receptor (PPAR) gamma is a ligand-activated transcription factor and a member of the nuclear hormone receptor superfamily that is thought to be the master regulator of fat storage; however, the relationship between PPARgamma and insulin sensitivity is highly controversial. We show here that supraphysiological activation of PPARgamma by PPARgamma agonist thiazolidinediones (TZD) markedly increases triglyceride (TG) content of white adipose tissue (WAT), thereby decreasing TG content of liver and muscle, leading to amelioration of insulin resistance at the expense of obesity. Moderate reduction of PPARgamma activity by heterozygous PPARgamma deficiency decreases TG content of WAT, skeletal muscle, and liver due to increased leptin expression and increase in fatty acid combustion and decrease in lipogenesis, thereby ameliorating high fat diet-induced obesity and insulin resistance. Moreover, although heterozygous PPARgamma deficiency and TZD have opposite effects on total WAT mass, heterozygous PPARgamma deficiency decreases lipogenesis in WAT, whereas TZD stimulate adipocyte differentiation and apoptosis, thereby both preventing adipocyte hypertrophy, which is associated with alleviation of insulin resistance presumably due to decreases in free fatty acids, and tumor necrosis factor alpha, and up-regulation of adiponectin, at least in part. We conclude that, although by different mechanisms, both heterozygous PPARgamma deficiency and PPARgamma agonist improve insulin resistance, which is associated with decreased TG content of muscle/liver and prevention of adipocyte hypertrophy.

Increased expression of the sterol regulatory element-binding protein-1 gene in insulin receptor substrate-2(-/-) mouse liver

Insulin receptor substrate (IRS)-2(-/-) mice develop diabetes because of insulin resistance in the liver and failure to undergo beta-cell hyperplasia. Here we show by DNA chip microarray analysis that expression of the sterol regulatory element-binding protein (SREBP)-1 gene, a downstream target of insulin, was paradoxically increased in 16-week-old IRS-2(-/-) mouse liver, where insulin-mediated intracellular signaling events were substantially attenuated. The expression of SREBP-1 downstream genes, such as the spot 14, ATP citrate-lyase, and fatty acid synthase genes, was also increased. Increased liver triglyceride content in IRS-2(-/-) mice assures the physiological importance of SREBP-1 gene induction. IRS-2(-/-) mice showed leptin resistance; low dose leptin administration, enough to reduce food intake and body weight in wild-type mice, failed to do so in IRS-2(-/-) mice. Interestingly, high dose leptin administration reduced SREBP-1 expression in IRS-2(-/-) mouse liver. Thus, IRS-2 gene disruption results in leptin resistance, causing an SREBP-1 gene induction, obesity, fatty liver, and diabetes.

Inhibition of RXR and PPARgamma ameliorates diet-induced obesity and type 2 diabetes

PPARgamma is a ligand-activated transcription factor and functions as a heterodimer with a retinoid X receptor (RXR). Supraphysiological activation of PPARgamma by thiazolidinediones can reduce insulin resistance and hyperglycemia in type 2 diabetes, but these drugs can also cause weight gain. Quite unexpectedly, a moderate reduction of PPARgamma activity observed in heterozygous PPARgamma-deficient mice or the Pro12Ala polymorphism in human PPARgamma, has been shown to prevent insulin resistance and obesity induced by a high-fat diet. In this study, we investigated whether functional antagonism toward PPARgamma/RXR could be used to treat obesity and type 2 diabetes. We show herein that an RXR antagonist and a PPARgamma antagonist decrease triglyceride (TG) content in white adipose tissue, skeletal muscle, and liver. These inhibitors potentiated leptin's effects and increased fatty acid combustion and energy dissipation, thereby ameliorating HF diet-induced obesity and insulin resistance. Paradoxically, treatment of heterozygous PPARgamma-deficient mice with an RXR antagonist or a PPARgamma antagonist depletes white adipose tissue and markedly decreases leptin levels and energy dissipation, which increases TG content in skeletal muscle and the liver, thereby leading to the re-emergence of insulin resistance. Our data suggested that appropriate functional antagonism of PPARgamma/RXR may be a logical approach to protection against obesity and related diseases such as type 2 diabetes.

[Bilateral progressive supra-fixing eyes with congenital misinsertion of inferior rectus muscles--a case report]

BACKGROUND

We report on a rare case with misinsertion of the inferior rectus muscles, that showed bilateral progressive supra-fixing eyes.

CASE

A 68-year-old woman showed bilateral progressive supra-fixing eyes with low vision that was caused by microcorneas and retionochoroidal atrophy. Passive infraduction was restricted bilaterally, but the right inferior rectus muscle was innervated normally. Magnytic resonance imaging(MRI) demonstrated nasal misposition of bilateral inferior rectus muscles. The patient's eye position was improved after combined transposition of the inferior rectus muscles that were misinserted nasally to the inferior poles of the eyes and superior rectus muscle recession, without any complications.

CONCLUSION

A dysfunction of bilateral depressor muscles and low vision may cause this condition. Accurate diagnosis with MRI and correction of the affected muscles to the normal anatomical position produces satisfying results in such cases.

Methyl-4-phenylpyridinium (MPP(+))-evoked dopamine release from rat striatal slices: possible roles of voltage-dependent calcium channels and reverse dopamine transport

We examined the properties of voltage-dependent Ca(2+) channels (VDCCs) mediating 1-methyl-4-phenylpyridinium (MPP(+))-evoked [3H]DA release from rat striatal slices. In some cases, the Ca(2+)-independent efflux of neurotransmitters is mediated by the high-affinity neurotransmitter-uptake systems. To determine whether such a mechanism might be involved in MPP(+)-evoked [3H]DA release. MPP(+) (1,10 and 100 microM) evoked the release of [3H]DA from rat striatal slices in a concentration-dependent manner. In the absence of Ca(2+), MPP(+) (10 and 100 microM)-evoked [3H]DA release was significantly decreased to approximately 50% of control (a physiological concentration of Ca(2+)). In the presence of Ca(2+), nomifensine (0.1,1 and 10 microM) dose-dependently and significantly inhibited the MPP(+)-evoked release of [3H]DA. Nomifensine (1 and 10 microM) also dose-dependently and significantly inhibited the MPP(+)-evoked release of [3H]DA under Ca(2+)-free conditions. MPP(+)-evoked [3H]DA release was partly inhibited by nicardipine (1 and 10 microM), an L-type Ca(2+) channel blocker. On the other hand, the N-type Ca(2+) channel blocker omega-conotoxin-GVIA (omega-CTx-GVIA) (1 and 3 microM) did not affect this release. omega-agatoxin-IVA (omega-Aga-IVA) at low concentrations (0.1 microM), which are sufficient to block P-type Ca(2+) channels alone, also had no effect. On the other hand, MPP(+)-evoked [3H]DA release was significantly decreased by high concentrations of omega-Aga-IVA (0.3 microM) that would inhibit Q-type Ca(2+) channels. In addition, application of the Q-type Ca(2+) channel blocker omega-conotoxin-MVIIC (omega-CTx-MVIIC) (0.3 and 1 microM) also significantly inhibited MPP(+)-evoked [3H]DA release. These results suggest that MPP(+)-evoked [3H]DA release from rat striatal slices is largely mediated by Q-type Ca(2+) channels, and the Ca(2+)-independent component is mediated by reversal of the DA transport system.

The fat-derived hormone adiponectin reverses insulin resistance associated with both lipoatrophy and obesity

Adiponectin is an adipocyte-derived hormone. Recent genome-wide scans have mapped a susceptibility locus for type 2 diabetes and metabolic syndrome to chromosome 3q27, where the gene encoding adiponectin is located. Here we show that decreased expression of adiponectin correlates with insulin resistance in mouse models of altered insulin sensitivity. Adiponectin decreases insulin resistance by decreasing triglyceride content in muscle and liver in obese mice. This effect results from increased expression of molecules involved in both fatty-acid combustion and energy dissipation in muscle. Moreover, insulin resistance in lipoatrophic mice was completely reversed by the combination of physiological doses of adiponectin and leptin, but only partially by either adiponectin or leptin alone. We conclude that decreased adiponectin is implicated in the development of insulin resistance in mouse models of both obesity and lipoatrophy. These data also indicate that the replenishment of adiponectin might provide a novel treatment modality for insulin resistance and type 2 diabetes.

Outcome of surgery for congenital fibrosis of the inferior rectus muscle

PURPOSE

To report clinical findings and surgical outcome in a large series of patients with fibrosis of the inferior rectus muscle.

MATERIALS AND METHODS

Subject Cases: A total of 17 cases were diagnosed with unilateral fibrosis of the inferior rectus muscle during the past 27 years at our institution. They were aged from 5 months to 17 years, with 15 cases under 10 years of age. No differences were present regarding the laterality or gender.

FINDINGS

All the cases showed hypotropia with restricted eye elevation. Forced duction test showed resistance to upward eye movement. A horizontal deviation in primary eye position was also present in 10 cases (59%). The affected eye was amblyopic in the majority of cases. Binocular vision was absent in 15 of the 17 cases.

RESULTS

Surgical Outcome: All the cases received either recession or free tenotomy of the inferior rectus muscle. Resection of the ipsilateral superior rectus muscle was additionally performed to correct residual hypotropia. Fibrosis of the inferior rectus was present as intraoperative finding in all the 17 cases. Hypotropia disappeared in 10 cases and decreased in 7 cases. Restoration of satisfactory binocular alignment was obtained in all the 17 cases.

CONCLUSION

Recession of the inferior rectus muscle was effective treatment for fibrosis of the inferior rectus. Additional resection of the ipsilateral superior rectus muscle was useful to correct residual hypotropia. Free tenotomy is not recommended.

Restoring ovulation in beef donor cows with ovarian cysts by progesterone-releasing intravaginal silastic devices

The objective of this study was to determine the efficacy of a progesterone-releasing intravaginal silastic device (Controlled Internal Drug Release: CIDR) for inducing ovulation in beef cows with persistent ovarian cysts. Fifteen cows with cysts and abnormal cycles for over 40 days were randomly assigned to receive either a single CIDR (CIDR group, n=9), or a CIDR containing no progesterone (blank CIDR) (BLANK group, n=6) for about 14 days. Determination of plasma progesterone levels at the beginning of CIDR treatment indicated 4 of 6 BLANK cows with non-luteinized cysts and 5 of 9 CIDR cows with non-luteinized cysts. In 5 of 6 BLANK cows, one follicular wave appeared and newly emerged dominant follicles increased in size up to 20 mm in diameter and persisted during the experiment, while one cow experienced estrus with spontaneous ovulation. In contrast, during CIDR treatment, 2 or 3 waves, in which dominant follicles were from 7 to 15 mm in diameter, appeared approximately at 7-day intervals. Within 3 days after CIDR removal, estrous behavior was detected followed by ovulation of the dominant follicle in the last wave. All CIDR cows resumed normal cyclicity with 2 follicular waves for over 2 months. Insertion of a CIDR caused a rapid increase of about 2 ng/mL in plasma progesterone. The levels were greater than 1.3 ng/mL until removal of a CIDR, then dropped under 0.3 ng/mL. Concentrations of plasma estradiol in BLANK cows increased during growth of the cystic follicles, with high levels greater than 10 pg/mL for over 10 days. In 4 of 5 cows with non-luteinized cysts, with high plasma estradiol on the day of CIDR insertion, CIDR treatment resulted in rapid decline of estradiol levels. During placement of the CIDR, estradiol levels showed no increase in the growth phase of a newly appeared dominant follicle. After CIDR removal, however, estradiol significantly increased associated with the growth of ovulatory follicles in all 9 cows. A transient increase in plasma FSH levels preceded detection of each follicular or cyst wave in both BLANK and CIDR cows. Pulse frequency and mean concentration of LH in cows with non-luteinized cysts showed values corresponding to those in normal follicular phase. However, throughout CIDR treatment, these parameters reduced to levels found in the normal luteal phase. In cows with luteinized cysts, parameters of LH secretion were as low as in the normal luteal phase before and during CIDR treatment, then increased significantly after CIDR removal. Present results indicate that treatment with CIDR proved effective in restoring ovulation and reestablishing normal cyclicity in beef donor cows with cysts persistent for a long period. The CIDR reduced and maintained LH secretion at normal luteal levels, thereby, inducing atresia of estrogen-active cysts and preventing formation of cysts from the newly emerged follicles.

[Secondary eosinophilia in a patient with hypereosinophilic syndrome after allogeneic bone marrow transplantation from a sibling donor]

A 23-year-old man first visited a local hospital in 1998 because of exertional dyspnea. Peripheral blood examination revealed mild leukocytosis with 82% eosinophils, and he was treated with prednisolone. As the eosinophilia did not improve, he was referred to Tokai University Hospital in March 1999 for further diagnosis and treatment. The patient was diagnosed as having hypereosinophilic syndrome (HES) because of unexplained hypereosinophilia persisting for more than 6 months, resulting in cardiac dysfunction. His disease was progressive in spite of immunosuppressive therapy, interferon-alpha and cytotoxic chemotherapy. Since he had an HLA-identical brother, allogeneic bone marrow transplantation (BMT) was performed in October 1999. After completion of the immunosuppressive therapy on day 79 after BMT, the number of eosinophils gradually increased again. Although we suspected recurrence of the disease, DNA fingerprinting revealed that the peripheral granulocytes were 100% donor type. An increase of interleukin-5 (IL-5) produced by peripheral lymphocytes and a decrease of the Th1/2 ratio suggested that the eosinophilia was related to GVHD. The eosinophilia was eventually controlled by cyclosporin. We conclude that DNA fingerprinting and examination of the IL-5 level and Th1/2 ratio are useful for differentiating between relapse and GVHD in cases of eosinophilia occurring after BMT for HES.

Subcellular localization of insulin receptor substrate family proteins associated with phosphatidylinositol 3-kinase activity and alterations in lipolysis in primary mouse adipocytes from IRS-1 null mice

To clarify the roles of insulin receptor substrate (IRS) family proteins in phosphatidylinositol (PI) 3-kinase activation and insulin actions in adipocytes, we investigated the intracellular localization of IRS family proteins and PI 3-kinase activation in response to insulin by fractionation of mouse adipocytes from wild-type and IRS-1 null mice. In adipocytes from wild-type mice, tyrosine-phosphorylated IRS-1 and IRS-2, which were found to associate with PI 3-kinase in response to insulin, were detected in the plasma membrane (PM) and low-density microsome (LDM) fractions. By contrast, tyrosine-phosphorylated IRS-3 (pp60), which was found to associate with PI 3-kinase, was predominantly localized in the PM fraction. In adipocytes from IRS-1-null mice, insulin-stimulated PI 3-kinase activity in anti-phosphotyrosine (alphaPY) immunoprecipitates in the LDM fraction was almost exclusively mediated via IRS-2 and was reduced to 25%; however, insulin-stimulated PI 3-kinase activity in the PM fraction was primarily mediated via IRS-3 and was reduced to 60%. To determine the potential functional impact of the distinct subcellular localization of IRSs and associating PI 3-kinase activity on adipocyte-specific metabolic actions, we examined lipolysis in IRS-1 null mice. The level of isoproterenol-induced lipolysis was increased 5.1-fold in adipocytes from IRS-1 null mice as compared with wild-type mice. Moreover, hormone-sensitive lipase (HSL) protein was increased 4.3-fold in adipocytes from IRS-1-null mice compared with wild-type mice, and HSL mRNA expression was also increased. The antilipolytic effect of insulin in IRS-1 null adipocytes, however, was comparable to that in wild-type mice. Thus, discordance between these two insulin actions as well as the transcriptional and translational effect (HSL mRNA and protein regulation) and the PM effect (antilipolysis) of insulin may be explained by distinct roles of both PI 3-kinase activity associated with IRS-1/IRS-2 and PI 3-kinase activity associated with IRS-3 in insulin actions related to their subcellular localization.

Esotropia surgery in children: long term outcome regarding changes in binocular alignment; a study of 956 cases

PURPOSE

To study the correlation between the outcome at 1 month (when the postoperative eye position is at the earliest stabilized), and 4 years after surgery.

METHOD

Retrospective review of medical records.

CASES

The authors reviewed 956 patients under 15 years of age who underwent unilateral or bilateral recession of the medial rectus muscle during a 22 year period representing the entire practice period of the senior author since the department was founded in 1977. The series comprised 521 cases of congenital/infantile esotropia (manifest before 6 months of age with no accommodative component) and 435 cases of acquired esotropia (manifest after 6 months of age with no accommodative component or with an accommodative component but excluding those with a high AC/A ratio). A consistent surgical plan was employed throughout this period for each condition.

RESULTS

Both types of esotropia showed a slight tendency to become exotropic during the 4 years after surgery. There was no difference in general success with regard to the reconstructive restoration of normal appearance or improvement of appearance between 1 month and 4 years after surgery. Patients with normal retinal correspondence or simultaneous perception achieved better binocular alignments at the 4 year followup than those who did not have such sensory binocular cooperation.

CONCLUSIONS

In infantile and acquired esotropia, it is essential that orthotropia or minimal esotropia be present at 1 month of surgery in order to obtain a binocular alignment within +/- 4 PD of orthotropia 4 years after surgery. It is strongly recommended to avoid overcorrection (consecutive exotropia) at 1 month after surgery for both congenital/infantile and acquired esotropia.

[A clear cell type meningioma in the upper eyelid ascertained by immunohistochemical examination]

BACKGROUND

We encountered a rare case of clear cell meningioma in the upper eyelid.

CASE

A 66-year-old man presented with a slow by progressive, well-defined, soft globelar tumor in the left upper eyelid. The tumor showed homogeneous isodensity and was contrasty in a computed tomograph. Histologically, oval-shaped cells with clear cytoplasm had both streamed and whorl configurations, but showed neither psammomas nor calcification. Immunohistochemically, vimentin, epithelial membrane antigen, and protein S-100 were expressed by the tumor cells.

CONCLUSIONS

Eyelid meningioma may originate from embryonal remains of the arachnoid in the sheath around the trigeminal nerve, and may vary histologically. Immunohistochemical examination helps to define cases of uncommon subtypes of meningioma.

Epigenetic silencing of PEG3 gene expression in human glioma cell lines

Genomic imprinting, the phenomenon in which alleles of genes are expressed differentially depending on their parental origins, has important consequences for mammalian development, and disturbance of normal imprinting leads to abnormal embryogenesis and some inherited diseases and is also associated with various cancers. In the context of screening for novel imprinted genes on human chromosome 19q13.4 with mouse A9 hybrids, we identified a maternal allele-specific methylated CpG island in exon 1 of paternally expressed imprinted gene 3 (PEG3), a gene that exhibits paternal allele-specific expression. Because PEG3 expression is downregulated in some gliomas and glioma cell lines, despite high-level expression in normal brain tissues, we investigated whether the loss of PEG3 expression is related to epigenetic modifications involving DNA methylation. We found monoallelic expression of PEG3 in all normal brain tissues examined and five of nine glioma cell lines that had both unmethylated and methylated alleles; the remaining four glioma cell lines exhibited gain of imprinting with hypermethylated alleles. In addition, treatment of glioma cell lines with the DNA demethylating agent 5-aza-2'-deoxycytidine reversed the silencing of PEG3 biallelically. In this article, we report that the epigenetic silencing of PEG3 expression in glioma cell lines depends on aberrant DNA methylation of an exonic CpG island, suggesting that PEG3 contributes to glioma carcinogenesis in certain cases.

Outcome of surgery in 124 cases of Duane's Retraction Syndrome (DRS) treated by intraoperatively graduated recession of the medial rectus for esotropic DRS, and of the lateral rectus for exotropic DRS

PURPOSE

To determine the outcome and effectiveness of simple horizontal muscle recession surgery in Duane's Retraction Syndrome (DRS).

CASES & METHODS

A total of 194 cases of DRS were operated on by us during the past 25 years. Surgery was aimed at improving the binocular alignment and eye position at the primary position as well as any abnormal head posture. Sufficient data were available in 124 cases. Recession of the medial rectus muscle was performed on 76 cases with esotropia and of the lateral rectus on 48 cases with exotropia. Recession dosage was determined during surgery based on three factors: size of the preoperative strabismus in primary position; forced ductions/resistance to traction, and the appearance of the rectus muscle at surgery.

RESULTS

Both the primary eye position and the abnormal head posture were satisfactorily improved in 119 cases (89%) after surgery with a result rated "excellent" or "good" by a residual deviation of 7 degrees or less and a definitely improved abnormal head posture, for all types of DRS deviations.

CONCLUSION

Recession of the appropriate horizontal rectus muscle is a safe and effective primary procedure for both the primary deviation and abnormal head posture in all types of DRS.

Regulation of serotonin transporter gene expression in human glial cells by growth factors

The aims of this study were to identify monoamine transporters expressed in human glial cells, and to examine the regulation of their expression by stress-related growth factors. The expression of serotonin transporter mRNA was detected by reverse transcriptase-polymerase chain reaction in normal human astrocytes, whereas the dopamine transporter (DAT) and the norepinephrine transporter (NET) were not detected. The cDNA sequence of the "glial" serotonin transporter in astrocytes was consistent with that reported for the "neuronal" serotonin transporter (SERT). Moreover, we also demonstrated SERT expression in glial fibrillary acidic protein-positive cells by immunocytochemical staining in normal human astrocytes. Serotonin transporter gene expression was also detected in glioma-derived cell lines (A172, KG-1-C and KGK). Addition of basic fibroblast growth factor (bFGF) or epidermal growth factor (EGF) for 2 days increased serotonin transporter gene expression in astrocytes and JAR (human choriocarcinoma cell line). Basic fibroblast growth factor, but not epidermal growth factor, increased specific [3H]serotonin uptake in astrocytes in a time (1-4 days)- and concentration (20-100 ng/ml)-dependent manner. The expression of genes for basic fibroblast growth factor and epidermal growth factor receptors was detected in astrocytes. These findings suggest that the expression of the serotonin transporter in human glial cells is positively regulated by basic fibroblast growth factor.

Essential role of insulin receptor substrate 1 (IRS-1) and IRS-2 in adipocyte differentiation

To investigate the role of insulin receptor substrate 1 (IRS-1) and IRS-2, the two ubiquitously expressed IRS proteins, in adipocyte differentiation, we established embryonic fibroblast cells with four different genotypes, i.e., wild-type, IRS-1 deficient (IRS-1(-/-)), IRS-2 deficient (IRS-2(-/-)), and IRS-1 IRS-2 double deficient (IRS-1(-/-) IRS-2(-/-)), from mouse embryos of the corresponding genotypes. The abilities of IRS-1(-/-) cells and IRS-2(-/-) cells to differentiate into adipocytes are approximately 60 and 15%, respectively, lower than that of wild-type cells, at day 8 after induction and, surprisingly, IRS-1(-/-) IRS-2(-/-) cells have no ability to differentiate into adipocytes. The expression of CCAAT/enhancer binding protein alpha (C/EBPalpha) and peroxisome proliferator-activated receptor gamma (PPARgamma) is severely decreased in IRS-1(-/-) IRS-2(-/-) cells at both the mRNA and the protein level, and the mRNAs of lipoprotein lipase and adipocyte fatty acid binding protein are severely decreased in IRS-1(-/-) IRS-2(-/-) cells. Phosphatidylinositol 3-kinase (PI 3-kinase) activity that increases during adipocyte differentiation is almost completely abolished in IRS-1(-/-) IRS-2(-/-) cells. Treatment of wild-type cells with a PI 3-kinase inhibitor, LY294002, markedly decreases the expression of C/EBPalpha and PPARgamma, a result which is associated with a complete block of adipocyte differentiation. Moreover, histologic analysis of IRS-1(-/-) IRS-2(-/-) double-knockout mice 8 h after birth reveals severe reduction in white adipose tissue mass. Our results suggest that IRS-1 and IRS-2 play a crucial role in the upregulation of the C/EBPalpha and PPARgamma expression and adipocyte differentiation.

A low-pH culture condition enhances the radiosensitizing effect of wortmannin

PURPOSE

The radiosensitizing effect of wortmannin on human tumor cells in a low-pH microenvironment was compared with that in a neutral-pH environment.

METHODS AND MATERIALS

A172 human glioblastoma cells, A549 human lung adenocarcinoma cells, and HMV-1 human melanoma cells were treated with 20 microM wortmannin 2 h before irradiation, and cell survival was examined. A low-pH microenvironment was simulated by exposing cells to low-pH culture medium for 24 h before wortmannin treatment. The effects of wortmannin on the repair of DNA double-strand breaks (dsbs) after 50-Gy irradiation in both low- and neutral-pH conditions were measured by pulsed-field gel electrophoresis. Expression of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) in low-pH conditions was also compared with that in neutral-pH conditions by Western blot analysis.

RESULTS

The radiosensitizing effect of wortmannin was greater in low-pH cultures than in neutral-pH cultures for all cell lines. The fast-rejoining component of DNA dsb repair was inhibited more strongly in low-pH than in neutral-pH conditions, although there was little difference in DNA-PKcs expression between groups.

CONCLUSIONS

The low-pH culture condition, which was designed to mimic the microenvironment of the central tumor mass in actively proliferating solid tumors, enhanced the radiosensitizing effect of wortmannin by inhibiting the fast-rejoining component of DNA dsb repair and by prolonging the retention of nonrejoined DNA dsbs.

[Music therapy induced alternations in natural killer cell count and function]

The effects of music therapy on natural killer (NK) cell count and activity (NKCA) were studied in 19 persons. Alzheimer's disease, cerebrovessel disease and Parkinson's disease subjects were assigned to a music therapy. Blood samples were drawn at rest and after completion of music therapy. Music therapy did not change the number of circulating lymphocytes. The percentage of NK cells increased during music therapy, along with an increase in the NK cell activity. The proportion of T cells, CD4 and CD8 did not change significantly during music therapy. One hour after the music therapy session, plasma adrenaline increased but cortisol and noradrenalin did not change. The results indicate that music therapy can significantly increase NK cell count and activity. The change in NK cell and function were independent of neuro-degenerative diseases.

Endogenous PPAR gamma mediates anti-inflammatory activity in murine ischemia-reperfusion injury

BACKGROUND & AIMS

Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor whose activation has been linked to several physiologic pathways including those related to the regulation of intestinal inflammation. We sought to determine whether PPAR gamma could function as an endogenous anti-inflammatory pathway in a murine model of intestinal ischemia-reperfusion (I/R) injury.

METHODS

PPAR gamma-deficient and wild-type mice were examined for their response to I/R procedure. Treatment with a PPAR gamma-specific ligand was also performed.

RESULTS

In a murine model of intestinal I/R injury, we observed more severe injury in PPAR gamma-deficient mice and protection against local and remote tissue injury in mice treated with a PPAR gamma-activating ligand, BRL-49653. Activation of PPAR gamma resulted in down-regulation of intercellular adhesion molecule 1 expression by intestinal endothelium and tissue tumor necrosis factor alpha messenger RNA levels most likely by inhibition of the NF-kappa B pathway.

CONCLUSIONS

These data strongly suggest that an endogenous PPAR gamma pathway exists in tissues that may be amenable to therapeutic manipulation in I/R-related injuries.