Surrogate estimates of insulin sensitivity in subjects with hypertension

The purpose of the study is to compare surrogate estimates of insulin sensitivity with a directly measured insulin sensitivity index, steady-state plasma glucose (SSPG) from insulin suppression test (IST), in subjects with hypertension. Two hundred and twenty-eight hypertensive patients who received IST for SSPG were included for analysis. Estimates from fasting measurements alone, homeostasis model assessment for insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI)), and indices from fasting and/or 2 h samples (ISI(0,120) and ISI(TX)) were calculated. In addition to Pearson and partial correlations, variance-component models were used to test the relationship between surrogate estimates of insulin sensitivity and SSPG. A large proportion of variance owing to covariates in the variance-component models indicated the goodness of model fit, irrespective of the independence among variables. SSPG was positively correlated with logarithmic transformation (Log) (HOMA-IR) and negatively correlated with QUICKI, Log (ISI(0,120)) and ISI(TX) (all P<0.0001). Log (ISI(0,120)) seemed to have a better correlation with SSPG (r=-0.72) than other measures in partial correlation. The proportion of variance owing to all covariates of Log (ISI(0,120)) and ISI(TX) were larger than those of Log (HOMA-IR) and QUICKI in the variance-component models. After adjustments for demographic and obesity covariates, the proportion of variance explained by Log (ISI(0,120)) were largest among the surrogate measures in the variance-component models. Our results showed that ISI(0,120) and ISI(TX) correlated better with SSPG than those used fasting measures alone (HOMA-IR and QUICKI). Log (ISI(0,120)) currently showing the strongest association with SSPG than other estimates is adaptable for use in large studies of hypertension.

Recombinant human acid [alpha]-glucosidase: major clinical benefits in infantile-onset Pompe disease

BACKGROUND

Pompe disease is a progressive metabolic neuromuscular disorder resulting from deficiency of lysosomal acid alpha-glucosidase (GAA). Infantile-onset Pompe disease is characterized by cardiomyopathy, respiratory and skeletal muscle weakness, and early death. The safety and efficacy of recombinant human (rh) GAA were evaluated in 18 patients with rapidly progressing infantile-onset Pompe disease.

METHODS

Patients were diagnosed at 6 months of age and younger and exhibited severe GAA deficiency and cardiomyopathy. Patients received IV infusions of rhGAA at 20 mg/kg (n = 9) or 40 mg/kg (n = 9) every other week. Analyses were performed 52 weeks after the last patient was randomized to treatment.

RESULTS

All patients (100%) survived to 18 months of age. A Cox proportional hazards analysis demonstrated that treatment reduced the risk of death by 99%, reduced the risk of death or invasive ventilation by 92%, and reduced the risk of death or any type of ventilation by 88%, as compared to an untreated historical control group. There was no clear advantage of the 40-mg/kg dose with regard to efficacy. Eleven of the 18 patients experienced 164 infusion-associated reactions; all were mild or moderate in intensity.

CONCLUSIONS

Recombinant human acid alpha-glucosidase is safe and effective for treatment of infantile-onset Pompe disease. Eleven patients experienced adverse events related to treatment, but none discontinued. The young age at which these patients initiated therapy may have contributed to their improved response compared to previous trials with recombinant human acid alpha-glucosidase in which patients were older.

Plasma vitrification and re-use of non-combustible fiber reinforced plastic, gill net and waste glass

Fiber reinforced plastic (FRP) composite material has widespread use in general tank, special chemical tank and body of yacht, etc. The purpose of this study is directed towards the volume reduction of non-combustible FRP by thermal plasma and recycling of vitrified slag with specific procedures. In this study, we have employed three main wastes such as, FRP, gill net and waste glass. The thermal molten process was applied to treat vitrified slag at high temperatures whereas in the post-heat treatment vitrified slags were mixed with specific additive and ground into powder form and then heat treated at high temperatures. With a two-stage heat treatment, the treated sample was generated into four crystalline phases, cristobalite, albite, anorthite and wollastonite. Fine and relatively high dense structures with desirable properties were obtained for samples treated by the two-stage heating treatment. Good physical and mechanical properties were achieved after heat treatment, and this study reveals that our results could be comparable with the commercial products.

Access to bone mineral density testing in patients at risk for osteoporosis

INTRODUCTION

Prior studies have documented suboptimal diagnosis and treatment for osteoporosis in many settings. Consistent predictors of suboptimal management include patient age, physician training, and physician gender. We assessed whether access to bone mineral density (BMD) testing was a predictor of osteoporosis management in an at-risk population of patients from New Jersey.

METHODS

Based on health care claims data, we identified three groups of at-risk beneficiaries, including women >or=65 (n=8,283), men and women >or=45 with a fracture (n=740), and men and women >or=45 taking chronic oral glucocorticoids (n=616). As the outcome of interest, we determined whether beneficiaries had undergone a BMD test and/or filled a prescription for a medicine used for osteoporosis (alendronate, calcitonin, hormone therapy, etidronate, risedronate, raloxifene, teriparatide) during the period 1 September 2002-31 August 2004. We assessed the relationship between this outcome and access to BMD testing. Access was characterized using two different measures: (1) the estimated driving time between each beneficiary's residence and the nearest BMD testing center ("driving time") and (2) the number of persons >or=65 years of age per BMD testing machine ("BMD scanner ratio") for each of the 21 counties in New Jersey.

RESULTS

Of the 9,640 beneficiaries, we found that 3,104 (32%) had undergone a BMD test, 2,893 (30%) had filled a prescription for an osteoporosis medication, and 4,364 (45%) had one or both. Across the 21 counties of New Jersey, the percentage of at-risk patients who had a BMD test and/or medication for osteoporosis ranged from 38 to 52%. In models adjusted for patient factors and the clustering of patients in counties, driving time was not associated with patients being screened or treated for osteoporosis. The BMD scanner ratio was a weak predictor of osteoporosis management.

CONCLUSION

Among beneficiaries of one large health insurer in New Jersey, two different measures of access to BMD testing were not important predictors of receiving testing and/or medications for osteoporosis.

Biological Inhibitory Effects of the Chinese Herb Danggui on Brain Astrocytoma

OBJECTIVE

Previous studies have demonstrated the utility of the traditional Chinese herb danggui in the treatment of chronic myelogenous leukemia. Our aim was to examine whether it might similarly be used to treat glioblastoma multiforme.

METHODS

The lipid-soluble active ingredients of danggui were extracted with acetone (AS-AC) or chlorophenol (AS-CH) and their antiproliferative and proapoptotic effects were studiedin vitro on cultured GBM 8401 cells and in vivoon tumors in nude mice.

RESULTS

After a 24-hour treatment, either AS-AC or AS-CH at a lower (50 micro g/ml) and a higher concentration (100 micro g/ml) significantly inhibited the proliferative activity of GBM 8401 cultured cells by 30-50%, as well as the expression of cathepsin B and vascular endothelial growth factor (VEGF). In nude mice, the growth of the tumor was inhibited by 30% by AS-CH or AS-AC (20 mg/kg; p < 0.05) and by 60% by AS-CH or AS-AC (60 mg/kg; p < 0.05). AS-AC and AS-CH also significantly inhibited microvessel formation in the tumors of nude mice.

CONCLUSIONS

Danggui may inhibit tumor growth by reducing the level of VEGF and the proapoptotic protein, cathepsin B. Thus, danggui may be useful in the treatment of high-grade astrocytomas.

Changes of brachial flow-mediated vasodilation in different ischemic stroke subtypes

The relationship between endothelial dysfunction and stroke subtypes is unclear. We prospectively measured brachial flow-mediated vasodilation (FMD) in 143 patients with acute ischemic stroke and 40 controls. The overall stroke patients had impaired FMD, but only lacunar infarction had significantly impaired FMD vs the controls. Impaired FMD was an independent predictor for lacunar infarction. Ischemic stroke is associated with endothelial dysfunction, which is more conspicuous in lacunar infarction.

Chinese hamster ovary cell-derived recombinant human acid alpha-glucosidase in infantile-onset Pompe disease

OBJECTIVE

To conduct an open-label, multinational, multicenter study examining the safety and efficacy of recombinant human acid alpha-glucosidase (rhGAA) in treatment of infantile-onset Pompe disease.

STUDY DESIGN

We enrolled 8 infant patients who had Pompe disease with GAA activity <1% of normal, cardiomyopathy, and hypotonia. In the 52-week initial phase, rhGAA was infused intravenously at 10 mg/kg weekly; an extension phase continued survivors' treatment with 10 to 20 mg/kg of rhGAA weekly or 20 mg/kg every 2 weeks for as long as 153 weeks. Safety measurements included adverse events, laboratory tests, and anti-rhGAA antibody titers. Efficacy evaluations included survival, ventilator use, echocardiograms, growth, and motor and cognitive function.

RESULT

After 52 weeks of treatment, 6 of 8 patients were alive, and 5 patients were free of invasive ventilator support. Clinical improvements included ameliorated cardiomyopathy and improved growth and cognition. Five patients acquired new motor milestones; 3 patients walked independently. Four patients died after the initial study phase; the median age at death or treatment withdrawal for all patients was 21.7 months, significantly later than expected for patients who were not treated. Treatment was safe and well tolerated; no death was drug-related.

CONCLUSION

rhGAA improved ventilator-free survival, cardiomyopathy, growth, and motor function in patients with infantile-onset Pompe disease compared with outcomes expected for patients without treatment.

Association study of genetic polymorphisms of SLC2A10 gene and type 2 diabetes in the Taiwanese population

AIMS/HYPOTHESIS

The gene encoding solute carrier family 2, facilitated glucose transporter, member 10 (SLC2A10, previously known as glucose transporter 10 [GLUT10]) is a promising candidate gene for type 2 diabetes since it is highly expressed in liver and pancreas and is located on human chromosome region 20q12-q13.1, a region previously shown to harbour type 2 diabetes susceptibility genes. We investigated whether the SLC2A10 gene could be a type 2 diabetes susceptibility gene in the Taiwanese population.

SUBJECTS AND METHODS

Sequencing of SLC2A10 gene from 48 diabetic subjects detected short tandem repeat polymorphisms in the promoter region, but did not detect any other sequence variants or new single-nucleotide polymorphisms (SNPs) other than those already in the SNPper database ( http://snpper.chip.org ) (30 June 2005).

RESULTS

Using these genetic polymorphisms, we divided the SLC2A10 gene into four distinct linkage disequilibrium blocks and performed a case-control association study in a group of type 2 diabetes subjects (n = 375) and normoglycaemic individuals (n=377). The HapD (A-G-T-C) haplotype in block 3, a rare haplotype, which consisted of four SNPs (rs3092412, rs2235491, rs2425904 and rs1059217), was modestly associated with type 2 diabetes with a haplotype score of -2.95567 (p = 0.012 with the haplotype-specific test).

CONCLUSIONS/INTERPRETATION

Our results suggest that SLC2A10 genetic variations do not appear to be major determinants for type 2 diabetes susceptibility in the Taiwanese population.

Early, sustained efficacy of adeno-associated virus vector-mediated gene therapy in glycogen storage disease type Ia

The deficiency of glucose-6-phosphatase (G6Pase) underlies life-threatening hypoglycemia and growth retardation in glycogen storage disease type Ia (GSD-Ia). An adeno-associated virus (AAV) vector encoding G6Pase was pseudotyped as AAV8 and administered to 2-week-old GSD-Ia mice (n = 9). Median survival was prolonged to 7 months following vector administration, in contrast to untreated GSD-Ia mice that survived for only 2 weeks. Although GSD-Ia mice were initially growth-retarded, treated mice increased fourfold in weight to normal size. Blood glucose was partially corrected by 2 weeks following treatment, whereas blood cholesterol normalized. Glucose-6-phosphatase activity was partially corrected to 25% of the normal level at 7 months of age in treated mice, and blood glucose during fasting remained lower in treated, affected mice than in normal mice. Glycogen storage was partially corrected in the liver by 2 weeks following treatment, but reaccumulated to pre-treatment levels by 7 months old (m.o.). Vector genome DNA decreased between 3 days and 3 weeks in the liver following vector administration, mainly through the loss of single-stranded genomes; however, double-stranded vector genomes were more stable. Although CD8+ lymphocytic infiltrates were present in the liver, partial biochemical correction was sustained at 7 m.o. The development of efficacious AAV vector-mediated gene therapy could significantly reduce the impact of long-term complications in GSD-Ia, including hypoglycemia, hyperlipidemia and growth failure.

Ambulatory electrocardiogram analysis in infants treated with recombinant human acid α-glucosidase enzyme replacement therapy for Pompe disease

PURPOSE

Infantile Pompe disease is caused by deficiency of lysosomal acid alpha-glucosidase. Trials with recombinant human acid alpha-glucosidase enzyme replacement therapy (ERT) show a decrease in left ventricular mass and improved function. We evaluated 24-hour ambulatory electrocardiograms (ECGs) at baseline and during ERT in patients with infantile Pompe disease.

METHODS

Thirty-two ambulatory ECGs were evaluated for 12 patients with infantile Pompe disease from 2003 to 2005. Patients had a median age of 7.4 months (2.9-37.8 months) at initiation of ERT. Ambulatory ECGs were obtained at determined intervals and analyzed.

RESULTS

Significant ectopy was present in 2 of 12 patients. Patient 1 had 211 and 229 premature ventricular contractions (0.2% of heart beats) at baseline and at 11.5 weeks of ERT, respectively. Patient 2 had 10,445 premature ventricular contractions (6.7% of heart beats) at 11 weeks of therapy.

CONCLUSION

Infantile Pompe disease may have preexisting ectopy; it may also develop during the course of ERT. Therefore, routinely monitoring patients using 24-hour ambulatory ECGs is useful. Periods of highest risk may be early in the course of ERT when there is a substantial decrease in left ventricular mass and an initial decrease in ejection fraction.

Electrocardiographic response to enzyme replacement therapy for Pompe disease

PURPOSE

Electrocardiogram (ECG) abnormalities are universal in infantile Pompe disease or glycogen storage disease type II, a fatal genetic muscle disorder caused by deficiency of acid alpha-glucosidase (GAA). Hallmarks of this disease include a shortened PR interval, an increased QT dispersion (QTd), and large left ventricular (LV) voltages. We evaluated the effect of recombinant human GAA (rhGAA) enzyme replacement therapy (ERT) on these ECG parameters in patients with infantile-onset Pompe disease.

METHODS

A total of 134 ECGs were evaluated from 19 patients (5 females and 14 males) with a median age of 5.5 months at the time of enrollment in open-label clinical trials exploring the safety and efficacy of ERT at a single center from 1999 to 2004. rhGAA was purified from genetically engineered Chinese hamster ovary cells overproducing GAA and infused intravenously at doses ranging from 10 mg/kg per week to 20 to 40 mg/kg every 2 weeks in patients with infantile-onset Pompe disease. The PR interval, QTd (longest to shortest QT), and LV voltage (SV1 + RV6) were blindly determined by two independent observers.

RESULTS

The median follow-up period was 6 months (range 2-30 months). The PR interval lengthened from 83 (42-110) ms to 107 (95-130) ms (P < .001), and the QTd decreased from 83 (40-125) ms to 53 (20-80) ms (P = .003). There were significant decreases in LV voltage (67 [17-83] mV vs. 48 [18-77] mV, P = .03), which correlated with decrease in LV mass on two-dimensional echocardiogram. There was no evident change in the QTc interval (429 [390-480] ms vs. 413 [370-450] ms, P = not significant).

CONCLUSION

rhGAA ERT for infantile Pompe disease results in an increase in PR interval and a decrease in both the QTd and the LV voltage. These results suggest that these ECG parameters may be useful markers of the severity of cardiac disease and the response to ERT treatment in patients with infantile Pompe disease.

Cutaneous phaeohyphomycosis caused by an Itraconazole and Amphoterecin B resistant strain of Veronaeae botryosa

BACKGROUND

Although the dematiaceous fungus Veronaea botryosa is rarely encountered clinically, it can be pathogenic.

METHODS

A patient with a history of diabetes mellitus, coronary artery disease, and Cushing's syndrome had recurrent multifocal, crusted, brownish-red noduloplaques on the right forearm, left upper limb, and right knee. A skin biopsy was obtained for histopathology and fungal cultures.

RESULTS

The histopathology showed brownish hyphae and yeast-like cells scattered in granulomatous infiltrates. Slide cultures revealed erect and straight conidiophores with two-celled cylindrical conidia, which have round tops and truncated bases. The fungus was identified as Veronaea botryosa. The disease slowly progressed despite a 6-month itraconazole regimen (200 mg daily). Subsequent use of Amphoterecin B produced only mild clinical improvements. Susceptibility tests showed resistance to both agents.

CONCLUSIONS

Cutaneous phaeohyphomycosis caused by V. botryosa is extremely rare. Antifungal susceptibility tests are important for choosing the appropriate drug and predicting the clinical outcome.

Mn,Cd-metallothionein-2: A room temperature magnetic protein

Naturally occurring metallothionein (MT) is a metal binding protein, which binds to seven Zn2+ through 20 conserved cysteines and forms two metal binding clusters with a Zinc-Blende structure. We demonstrate that the MT, when substituting the Zn2+ ions by Mn2+ and Cd2+, exhibits magnetic hysteresis loop observable by SQUID from 10 to 330 K. The magnetic moment may have originated from the bridging effect of the sulfur atoms between the metal ions that leads to the alignment of the electron spins of the Mn2+ ions inside the clusters. The protein backbone may restrain the net spin moment of Mn2+ ions from thermal fluctuation. The modified magnetic-metallothionein is a novel approach to creating molecular magnets with operating temperatures up to 330 K.

Dominant-negative effects of human P/Q-type Ca2+ channel mutations associated with episodic ataxia type 2

Episodic ataxia type 2 (EA2) is an inherited autosomal dominant disorder related to cerebellar dysfunction and is associated with mutations in the pore-forming alpha(1A)-subunits of human P/Q-type Ca(2+) channels (Cav2.1 channels). The majority of EA2 mutations result in significant loss-of-function phenotypes. Whether EA2 mutants may display dominant-negative effects in human, however, remains controversial. To address this issue, five EA2 mutants in the long isoform of human alpha(1A)-subunits were expressed in Xenopus oocytes to explore their potential dominant-negative effects. Upon coexpressing the cRNA of alpha(1A)-WT with each alpha(1A)-mutant in molar ratios ranging from 1:1 to 1:10, the amplitude of Ba(2+) currents through wild-type (WT)-Cav2.1 channels decreased significantly as the relative molar ratio of alpha(1A)-mutants increased, suggesting the presence of an alpha(1A)-mutant-specific suppression effect. When we coexpressed alpha(1A)-WT with proteins not known to interact with Cav2.1 channels, we observed no significant suppression effects. Furthermore, increasing the amount of auxiliary subunits resulted in partial reversal of the suppression effects in nonsense but not missense EA2 mutants. On the other hand, when we repeated the same coinjection experiments of alpha(1A)-WT and mutant using a splice variant of alpha(1A)-subunit that contained a considerably shorter COOH terminus (i.e., the short isoform), no significant dominant-negative effects were noted until we enhanced the relative molar ratio to 1:10. Altogether, these results indicate that for human WT-Cav2.1 channels comprising the long-alpha(1A)-subunit isoform, both missense and nonsense EA2 mutants indeed display prominent dominant-negative effects.

Expression of fragile X mental retardation-1 gene with nuclear export signal mutation changes the expression profiling of mouse cerebella immortal neuronal cell

Fragile X syndrome (FXS) is the most frequent cause of inherited mental retardation and is largely caused by a loss of expression of fragile X mental retardation protein (FMRP), encoded by fragile X retardation gene-1 (Fmr1). FMRP is a multifunction protein, with intrinsic RNA-binding properties, which is a component of ribonucleoprotein complex associated with polyribosomes. The properties of FMRP indicate that it might participate in post-transcriptional processes in the regulation of some mRNA species, including localization, stability and translational control. However, the function of FMRP related to the pathologenesis in FXS is largely unknown. Many efforts were undertaken to identify the putative specific RNA targets as well as the FMRP-related proteins and to identify the effect of FMRP absence on the corresponding proteins. Here we present our efforts using proteomics approach to explore the differential expression profiling of mouse cerebella immortal cell, in which we changed the expression of FMRP by expressing Fmr1 gene with nuclear export signal (NES) mutation. This mutation makes FMRP unable to shuttle from nucleus to cytoplasm and leads to nuclear instead of cytoplasmic location as usual, which was hypothesized to affect the pathways of groups of RNAs or proteins related with FMRP. In present study, 56 proteins were found to be differentially expressed in transfected R2 neuronal cells, including 16 decreased expressions and 40 increased expressions. The differentially expressed proteins play roles in diverse physiological processes, such as neuronal plasticity, spermatogenesis and craniofacial and limb development etc. In addition, the expressions of three mRNA identified as FMRP targets in fragile X cell were tested in present model cells. All these results provide new insights to the role of FMRP in the disease.

Evasion of immune responses to introduced human acid alpha-glucosidase by liver-restricted expression in glycogen storage disease type II

Glycogen storage disease type II (GSD-II; Pompe disease) is caused by a deficiency of acid alpha-glucosidase (GAA; acid maltase) and manifests as muscle weakness, hypertrophic cardiomyopathy, and respiratory failure. Adeno-associated virus vectors containing either a liver-specific promoter (LSP) (AAV-LSPhGAApA) or a hybrid CB promoter (AAV-CBhGAApA) to drive human GAA expression were pseudotyped as AAV8 and administered to immunocompetent GAA-knockout mice. Secreted hGAA was detectable in plasma between 1 day and 12 weeks postadministration with AAV-LSPhGAApA and only from 1 to 8 days postadministration for AAV-CBGAApA. No anti-GAA antibodies were detected in response to AAV-LSPhGAApA (<1:200), whereas AAV-CBhGAApA provoked an escalating antibody response starting 2 weeks postadministration. The LSP drove approximately 60-fold higher GAA expression than the CB promoter in the liver by 12 weeks following vector administration. Furthermore, the detected cellular immunity was provoked by AAV-CBhGAApA, as detected by ELISpot and CD4+/CD8+ lymphocyte immunodetection. GAA activity was increased to higher than normal and glycogen content was reduced to essentially normal levels in the heart and skeletal muscle following administration of AAV-LSPhGAApA. Therefore, liver-restricted GAA expression with an AAV vector evaded immunity and enhanced efficacy in GSD-II mice.

Amylopectinosis disease isolated to the heart with normal glycogen branching enzyme activity and gene sequence

We report a 17-month-old female patient with a rare cause of cardiomyopathy secondary to accumulation of amylopectin-like material (fibrillar glycogen) isolated to the heart. Evidence of amylopectinosis isolated to cardiac myocytes in this patient was demonstrated by histology and electron microscopy. Glycogen content, glycogen branching enzyme (GBE) activity, as well as phosphofructokinase enzyme activities measured in liver, skeletal muscle, fibroblasts and ex-transplanted heart tissue were all in the normal to lower normal ranges. Normal skeletal muscle and liver tissue histology and GBE activity, normal GBE activity in skin fibroblasts, plus normal GBE gene sequence in this patient exclude the classical branching enzyme deficiency (type IV GSD). We believe that this is an as yet uncharacterized and novel phenotype of GSD associated with cardiomyopathy, in which there is an imbalance in the regulation of glycogen metabolism limited to the heart.

Colonization and inflammation deficiencies in Mongolian gerbils infected by Helicobacter pylori chemotaxis mutants

Helicobacter pylori causes disease in the human stomach and in mouse and gerbil stomach models. Previous results have shown that motility is critical for H. pylori to colonize mice, gerbils, and other animal models. The role of chemotaxis, however, in colonization and disease is less well understood. Two genes in the H. pylori chemotaxis pathway, cheY and tlpB, which encode the chemotaxis response regulator and a methyl-accepting chemoreceptor, respectively, were disrupted. The cheY mutation was complemented with a wild-type copy of cheY inserted into the chromosomal rdxA gene. The cheY mutant lost chemotaxis but retained motility, while all other strains were motile and chemotactic in vitro. These strains were inoculated into gerbils either alone or in combination with the wild-type strain, and colonization and inflammation were assessed. While the cheY mutant completely failed to colonize gerbil stomachs, the tlpB mutant colonized at levels similar to those of the wild type. With the tlpB mutant, there was a substantial decrease in inflammation in the gerbil stomach compared to that with the wild type. Furthermore, there were differences in the numbers of each immune cell in the tlpB-mutant-infected stomach: the ratio of lymphocytes to neutrophils was about 8 to 1 in the wild type but only about 1 to 1 in the mutant. These results suggest that the TlpB chemoreceptor plays an important role in the inflammatory response while the CheY chemotaxis regulator plays a critical role in initial colonization. Chemotaxis mutants may provide new insights into the steps involved in H. pylori pathogenesis.

Intestinal adenocarcinoma with pancreas and lymph node metastases in a captive cotton-top tamarin (Saguinus oedipus)

A case of intestinal adenocarcinoma with metastases to the pancreas and regional lymph node was found in a 9-year-old, captive female cotton-top tamarin (Saguinus oedipus) with intermittent diarrhea. At necropsy, the tumor mass was located in the ileo-cecal junction causing circumferential thickening and annular stenosis. Microscopically, the lesions at primary and metastatic sites showed typical features of mucinous adenocarcinoma as seen in humans, including intracellular and extracellular mucin production and characteristic appearance of a signet ring of the tumor cells. The diagnosis was confirmed by histological evaluation, positive cytokeratin immunostain, and mucin production demonstrated by PAS and Alcian blue stain. It is speculated that the development of intestinal carcinoma was partly attributable to the excessive absorption of a diet of refined food, unbalanced nutrition, and the nature of these animals to develop stress easily.

Improved efficacy of gene therapy approaches for Pompe disease using a new, immune-deficient GSD-II mouse model

Glycogen storage disease type II (GSD-II) is a lysosomal storage disorder in which the lack of human acid-alpha glucosidase (hGAA) activity results in massive accumulations of glycogen in cardiac and skeletal muscle fibers. Affected individuals die of cardiorespiratory failure secondary to the skeletal and/or cardiac muscle involvement. Recombinant hGAA enzyme replacement therapy (ERT) is currently in clinical trials and, although promising, ERT may be limited by large-scale production issues and/or the need for frequent infusions. These limitations could be circumvented or augmented by gene therapy strategies. Previous findings in our lab demonstrated that hepatic targeting of a modified adenovirus vector expressing human GAA was able to correct the glycogen accumulation in multiple affected muscles in the GAA-KO mice, by virtue of high-level, hepatic secretion of hGAA. However, although the vector persisted and expressed hGAA for 6 months in the liver, plasma hGAA was not detectable beyond 10 dpi (days postinjection), and reaccumulation of glycogen was observed. Two possibilities may have contributed to this phenomenon, the shut down of the CMV promoter and/or the onset of high levels of anti-hGAA antibodies. In order to test these and other possibilities, we have now developed an immune-deficient mouse model of GSD-II by interbreeding GAA-KO mice with severe combined immune-deficient (SCID) mice, generating double knockout, GAA-KO/SCID mice. In this new mouse model, we evaluated the efficacy of an [E1-, polymerase-] AdhGAA vector, in the absence of anti-hGAA antibody responses. After intravenous injection, GAA detection in the plasma was prolonged for at least 6 months secondary to the lack of anti-hGAA antibody production in all of the treated mice. GAA-KO/SCID mice treated with high doses of viral vector demonstrated longer durations of glycogen correction in both skeletal and cardiac muscles, relative to mice injected with lower doses of the vector. Notably, within 2 weeks of vector injection, muscle strength and coordination was normalized, and the improved muscle function persisted for at least 6 months. In summary, this new mouse model of GSD-II now makes it possible to assess the full potential for efficacy of any GAA-expressing vector (and/or ERT) contemplated for use in GSD-II gene therapy, without the negative influence that anti-hGAA antibodies entail.

Characterization of senescence-associated proteases in postharvest broccoli florets

We characterized the senescence-associated proteases of postharvest broccoli (Brassica oleracea L. var Green King) florets, using class-specific protease inhibitors and gelatin-polyacrylamide gel electrophoresis. Different classes of senescence-associated proteases in broccoli florets were partially characterized for the first time. Protease activity of broccoli florets was depressed by all the inhibitors and showed different inhibition curves during postharvest. The hydrolytic activity of metalloprotease (EC 3.4.24. - ) and serine protease (EC 3.4.21. - ) reached a maximum, 1 day after harvest (DAH), then decreased, while the hydrolytic activity of cysteine protease (EC 3.4.22. - ) and aspartic protease (EC 3.4.23. - ) increased throughout the postharvest senescence based on the calculated inhibition percentage of protease activity. The senescence-associated proteases were separated into seven endoprotease (EP) groups by gelatin-polyacryamide gel electrophoresis and classified into EP1 (metalloprotease), EP2 (metalloprotease and cysteine protease), EP3 (serine protease and aspartic protease), EP4, EP5, EP7 (cysteine protease), and EP6 (serine protease) based on the sensitivity of class-specific protease inhibitors. The proteases EP2, EP3, and EP4 were present throughout the postharvest stages. EP3 was the major EP at all times during senescence; EP4 intensity of activity increased after 2 DAH; EP6 and EP7 clearly increased after 4 DAH. Our results suggest that serine protease activity contributes to early stage (0-1 DAH) and late stage (4-5 DAH) of senescence; metalloprotease activity was involved in the early and intermediate stages (0-3 DAH) of senescence; and cysteine protease and aspartic protease activities participated in the whole process of broccoli senescence.

Hypertension and impaired glycine handling in mice lacking the orphan transporter XT2

A family of orphan transporters has been discovered that are structurally related to the Na(+)-Cl(-)-dependent neurotransmitter transporters, including the dopamine transporter. One member of this family, the mouse XT2 gene, is predominantly expressed in the kidney and has 95% homology to rat ROSIT (renal osmotic stress-induced Na(+)-Cl(-) organic solute cotransporter). To study the physiological functions of this transporter, we generated XT2-knockout mice by gene targeting. XT2(-/-) mice develop and survive normally with no apparent abnormalities. To attempt to identify potential substrates for XT2, we screened urine from XT2-knockout mice by high-pressure liquid chromatography and mass spectrometry and found significantly elevated concentrations of glycine. To study glycine handling, XT2(+/+) and XT2(-/-) mice were injected with radiolabeled glycine, and urine samples were collected to monitor glycine excretion. After 2 h, XT2(-/-) mice were found to excrete almost twice as much glycine as the XT2(+/+) controls (P = 0.03). To determine whether the absence of the XT2 transporter affected sodium and fluid homeostasis, we measured systolic blood pressure by computerized tail-cuff manometry. Systolic blood pressure was significantly higher in XT2(-/-) mice (127 +/- 3 mmHg) than in wild-type controls (114 +/- 2 mmHg; P < 0.001). This difference in systolic blood pressure was maintained on high and low salt feeding. To examine whether the alteration in blood pressure and the defect in glycine handling were related, we measured systolic blood pressure in the XT2(-/-) mice during dietary glycine supplementation. Glycine loading caused systolic blood pressure to fall in the XT2(-/-) mice from 127 +/- 3 to 115 +/- 3 mmHg (P < 0.001), a level virtually identical to that of the wild-type controls. These data suggest that the XT2 orphan transporter is involved in glycine reabsorption and that the absence of this transporter is sufficient to cause hypertension.