Recommendations for eligibility criteria concerning bariatric and metabolic surgical and endoscopic procedures for obese Hong Kong adults 2024: Hong Kong Society for Metabolic and Bariatric Surgery Position Statement.

The surgical management of obesity in Hong Kong has rapidly evolved over the past 20 years. Despite increasing public awareness and demand concerning bariatric and metabolic surgery, service models generally are not standardised across bariatric practitioners. Therefore, a working group was commissioned by the Hong Kong Society for Metabolic and Bariatric Surgery to review relevant literature and provide recommendations concerning eligibility criteria for bariatric and metabolic interventions within the local population in Hong Kong. The current position statement aims to provide updated guidance regarding the indications and contraindications for bariatric surgery, metabolic surgery, and bariatric endoscopic procedures.

Preclinical safety evaluation of subretinal AAV2.sFlt-1 in non-human primates.

We report on the long-term safety of AAV2.sFlt-1 (a recombinant adeno-associated virus serotype 2 carrying the soluble form of the Flt-1 receptor) injection into the subretinal space of non-human primates. Levels of sFlt-1 protein were significantly higher (P<0.05) in the vitreous of four out of five AAV2.sFlt-1-injected eyes. There was no evidence of damage to the eyes of animals that received subretinal injections of AAV2.sFlt-1; ocular examination showed no anterior chamber flare, normal fundus and electroretinography responses equivalent to those observed before treatment. Notably, immunological analysis demonstrated that gene therapy involving subretinal injection of AAV2.sFlt-1 does not elicit cell-mediated immunity. Biodistribution analysis showed that AAV2.sFlt-1 could be detected only in the eye and not in the other organs tested. These data indicate that gene therapy with subretinal AAV2.sFlt-1 is safe and well tolerated, and therefore promising for the long-term treatment of neovascular diseases of the eye.

VEGF-induced choroidal damage in a murine model of retinal neovascularisation.

BACKGROUND/AIMS: Photoreceptor-specific upregulation of vascular endothelial growth factor (VEGF) in a transgenic mouse model (Kimba) of retinal neovascularisation induces retinal vascular damage which appears similar to that in diabetic retinopathy. Here we have determined whether the choroidal vasculature is also affected in Kimba. METHODS: Kimba mice were assessed with fundus fluorescein angiography for mild, moderate or severe retinal vascular leakage prior to preparation of choroidal corrosion casts for quantitative analysis using scanning electron microscopy. VEGF was located immunohistochemically. RESULTS: Choroidal abnormalities included microaneurysms, constriction, shrinkage and dropout in the capillaries and tortuosity and loops in the arteries and veins which were similar to those observed in corrosion casts of the human choroid in diabetes. Similar to human diabetes, choroidal neovascularisation was not observed. The severity of choroidal damage correlated with the extent of retinal vascular leakage. In addition to the expected presence of VEGF in photoreceptors, VEGF was also detected in the pigment epithelium and choroid in the transgenic mice. CONCLUSION: We show that elevated retinal VEGF levels trigger pathophysiological changes in the choroid. We suggest that therapies to prevent vascular damage in diabetes must target both the retinal and choroidal vasculatures.

Qualitative and quantitative analyses of nucleosides and nucleobases in Ganoderma spp. by HPLC-DAD-MS.

A high-performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS) analytical method was developed for detection of the nucleosides and nucleobases in two species of Lingzhi, the dried sporophore of Ganoderma lucidum and G. sinense. The method, combining advantages of both DAD and MS, was successfully used to qualitatively identify for six nucleosides namely, adenosine, cytidine, guanosine, inosine, thymidine, uridine and five nucleobases namely, adenine, guanine, hypoxanthine, thymine and uracil in Lingzhi samples. Quantitative analyses showed that uridine was the most abundant nucleoside in these Lingzhi samples and the contents of nine target analytes were found to be different in pileus and stipes of the fruiting bodies and among the different species of G. spp. The established method might apply as an alternative approach for the quality assessment of Lingzhi.

Long-term global retinal microvascular changes in a transgenic vascular endothelial growth factor mouse model.

AIMS/HYPOTHESIS: Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of diabetic retinopathy. We investigated whether transgenic mice with moderate VEGF expression in photoreceptors (trVEGF029) developed changes similar to diabetic retinopathy and whether retinopathy progressed with time. MATERIALS AND METHODS: Human VEGF(165) (hVEGF(165)) expression was analysed using ELISA and quantitative RT-PCR; serum glucose levels were also measured. Fundus fluorescein angiography (FA) was used to screen the degree of retinopathy from 6 weeks. Dynamic changes in the density of retinal microvasculature, as well as other changes similar to diabetic retinopathy, including retinal leucostasis, capillary endothelial cell and pericyte loss, and numbers of acellular capillaries, were quantified. RESULTS: trVEGF029 mice were normoglycaemic and showed a moderate, short-term hVEGF(165) upregulation for up to 3 weeks. Changes in the retinal microvasculature not only mimicked those seen in diabetic retinopathy, but also showed similar pathological progression with time. FA at 6 weeks identified two phenotypes, mild and moderate, which were distinguished by the extent of vascular leakage. Quantitative analysis of diabetic retinopathy-like changes revealed that these parameters were tightly correlated with the initial degree of vascular leakage; low levels reflected slow and limited retinal microvascular changes in mild cases and high levels reflected more rapid and extensive changes in moderate cases. CONCLUSIONS/INTERPRETATION: The data suggest that even an early short-term elevation in hVEGF(165) expression might set a train of events that lead to progressive retinopathy. Induction of many features characteristic of diabetic retinopathy in trVEGF029 enables mechanisms leading to the disease state to be examined, and provides a relevant animal model for testing novel therapeutics.

Generation of transgenic mice with mild and severe retinal neovascularisation.

AIM: To generate a mouse model for slow progressive retinal neovascularisation through vascular endothelial growth factor (VEGF) upregulation. METHODS: Transgenic mice were generated via microinjection of a DNA construct containing the human VEGF165 (hVEGF) gene driven by a truncated mouse rhodopsin promoter. Mouse eyes were characterised clinically and histologically and ocular hVEGF levels assayed by ELISA. RESULTS: One transgenic line expressing low hVEGF levels showed mild clinical changes such as focal fluorescein leakage, microaneurysms, venous tortuosity, capillary non-perfusion and minor neovascularisation, which remained stable up to 3 months postnatal. Histologically, there were some disturbance and thinning of inner and outer nuclear layers, with occasional focal areas of neovascularisation. By contrast, three other lines expressing high hVEGF levels presented with concomitantly severe phenotypes. In addition to the above, clinical features included extensive neovascularisation, haemorrhage, and retinal detachment; histologically, focal to extensive areas of neovascularisation associated with retinal folds, cell loss in the inner and outer nuclear layers, and partial retinal detachment were common. CONCLUSIONS: The authors generated four hVEGF overexpressing transgenic mouse lines with phenotypes ranging from mild to severe neovascularisation. These models are a valuable research tool to study excess VEGF related molecular and cellular changes and provide additional opportunities to test anti-angiogenic therapies.

Potential long-term inhibition of ocular neovascularisation by recombinant adeno-associated virus-mediated secretion gene therapy.

Neovascularisation (NV) within the eye often results in visual loss. Vascular endothelial growth factor (VEGF) has been implicated in the development of ocular NV. Previous studies have shown that VEGF antagonists successfully suppressed retinal and choroidal NV in animal models. However, the systemic approach and transient nature of the delivery systems used in these studies hinder therapeutic application. To achieve stable and localised ocular anti-angiogenic therapy, we explored the use of recombinant adeno-associated virus (rAAV)-mediated secretion gene therapy (SGT). In this study, we generated a rAAV vector encoding soluble VEGF receptor 1, sFlt-1 (AAV-CMV.sflt) and determined its ability to inhibit cautery-induced corneal NV and laser-induced choroidal NV. Delivery of AAV-CMV.sflt into the anterior chamber resulted in transgene expression in the iris pigment epithelium and corneal endothelium, which reduced the development of corneal NV in the stroma of cauterised rats by 36% compared with cauterised control groups (P = 0.009). Subretinal delivery of AAV-CMV.sflt near the equator of the eye also suppressed choroidal NV at the laser lesions around the optic nerve by 19% (P = 0.002), indicating that there was diffusion of the secreted anti-angiogenic protein across the retina. Both results suggest that the long-term suppression of ocular NV is possible through the use of stable rAAV-mediated SGT.

Inhibition of angiogenesis by adenovirus-mediated sFlt-1 expression in a rat model of corneal neovascularization.

Pathological angiogenesis, or the production of new capillary vessels from preexisting vasculature, within the eye is a serious event that often leads to blindness. Upregulation of vascular endothelial growth factor (VEGF) has been linked to neovascularization in the eye, suggesting that it could be a suitable target to inhibit angiogenic changes. This work investigated whether the presence of a proven antiangiogenic factor, the soluble variant of the VEGF receptor, sFlt-1, in the anterior chamber is sufficient to inhibit new vessel formation in the cornea in an animal model of corneal neovascularization. A recombinant adenovirus vector that can mediate efficient in vivo gene transfer and expression in ocular cells was selected as a delivery agent. We have shown that after the injection of Ad.betagal into the anterior chamber of normal and cauterized rat eyes, corneal endothelial cells and cells of the trabecular meshwork were efficiently transduced and that beta-galactosidase (beta-Gal) expression was maintained up to 10 days postinjection. Cauterization significantly increased the amount of immunoreactive VEGF in vehicle- or Ad.null-injected animals (t test, p < 0.001 and p < 0.001, respectively). However, when cauterization was combined with Ad.sflt injection there was no statistically significant increase in the amount of immunoreactive VEGF (p = 0.12). The injection of Ad.sflt into the anterior chamber slowed or inhibited VEGF-induced angiogenic changes. After cauterization, 100% of uninjected and vehicle-injected and 82% of Ad.null-injected animals developed moderate to severe corneal angiogenesis in contrast to 18% of Ad.sflt-injected animals. These in vivo results suggest that the transient presence of antiangiogenic agents in the anterior chamber can be successfully used to inhibit the development of corneal angiogenesis.

Identification and characterization of S2V, a novel putative siglec that contains two V set Ig-like domains and recruits protein-tyrosine phosphatases SHPs.

We describe the molecular cloning and characterization of S2V, a novel sialic acid binding immunoglobulin-like lectin. The cDNA of S2V encodes a type 1 transmembrane protein with four extracellular immunoglobulin-like (Ig-like) domains and a cytoplasmic tail bearing a typical immunoreceptor tyrosine-based inhibitory motif (ITIM) and an ITIM-like motif. A unique feature of S2V is the presence of two V-set Ig-like domains responsible for the binding to sialic acid, whereas all other known siglecs possess only one. S2V is predominantly expressed in macrophage. In vivo S2V was tyrosine-phosphorylated when co-expressed with exogenous c-Src kinase. Upon tyrosine phosphorylation, S2V recruits both Src homology 2 (SH2) domain-containing protein-tyrosine phosphatases SHP-1 and SHP-2, two important inhibitory regulators of immunoreceptor signal transduction. These findings suggest that S2V is involved in the negative regulation of the signaling in macrophage by functioning as an inhibitory receptor. When expressed in COS-7 cells, S2V was able to mediate sialic acid-dependent binding to human red blood cells, suggesting that S2V may function through cell-cell interaction.

Controlled production of active cathepsin D in retinal pigment epithelial cells following adenovirus-mediated gene delivery.

The transduction of a low cathepsin D-producing retinal pigment epithelial cell line with a recombinant adenovirus, Ad.proCatD, carrying a viral promoter and the precursor form of the lysosomal enzyme cathepsin D, procathepsin D, led to the upregulation of proCatD expression. However, the resultant aspartic protease activity did not exceed that observed in normal primary human retinal pigment epithelial cells. Following the injection of Ad. proCatD into rat eyes, immunohistochemistry and Western blot analysis localized the expression of procathepsin D to the retinal pigment epithelial cell layer and to the sclera/choroid/retinal epithelial cell layers, respectively. This upregulation of procathepsin D expression was accompanied by a limited increase in aspartic protease activity. The injected eyes did not demonstrate any of the retinal changes that have been associated with the overproduction and secretion of active cathepsin D. Immunoelectronmicroscopy of Ad.proCatD-transduced retinal pigment epithelial cells demonstrated the presence of cathepsin D not only in cytoplasmic vesicles and lysosomes but also in the nucleoli and, less strongly, elsewhere in euchromatic regions of some 10% of cells. In spite of the upregulated expression of procathepsin D, the production of active cathepsin D in Ad.proCatD-transduced retinal pigment epithelial cells was strictly controlled. It is proposed that active cathepsin D production is controlled at the point of posttranslational modification by an intranuclear feedback mechanism initiated by the relative excess of procathepsin D in Ad. proCatD-transduced retinal pigment epithelial cells.

The use of adenovirus-mediated gene transfer to develop a rat model for photoreceptor degeneration.

PURPOSE: To investigate the effects of recombinant adenovirus-mediated downregulation of cathepsin S (CatS) on the retinal pigment epithelium and/or neural retina in vivo. METHODS: The expression of green fluorescent protein (gfp) after subretinal injection of a recombinant adenovirus, Ad.gfp, into rat eyes was first established by in vivo fundus fluorescence photography and fluorescence microscopy. The autofluorescent debris accumulation in Ad.CatSAS (recombinant adenovirus carrying the antisense CatS gene)injected rat eyes was monitored by fluorescence microscopy, and the antisense CatS RNA expression was demonstrated by in situ hybridization. Changes in the retinal morphology were assessed by light microscopy. ResuLTS. The gfp expression was present in 30% to 90% of the injection area at 3 days and was absent 9 days after Ad.gfp injection. In Ad.CatSAS-injected eyes, the expression of antisense CatS RNA was demonstrated by in situ hybridization. Autofluorescent debris accumulation was significantly higher in Ad.CatSAS-injected eyes than in control eyes. The shortening of photoreceptor outer segments in Ad.CatSAS-injected eyes coincided with intense autofluorescent debris accumulation. The number of layers of photoreceptor cells decreased with time and were 11, 9, and 8 at 7, 14, and 28 days after Ad.CatSAS injection, respectively. In control eyes, the number of layers of photoreceptor cells (14) remained unchanged. CONCLUSIONS: These results demonstrate that recombinant adenovirus-mediated transient modulation of gene expression in retinal pigment epithelial (RPE) cells could induce changes in the retina, and, in spite of the low expression of endogenous CatS in RPE cells, this enzyme plays an important role in maintenance of normal retinal function.

Preferential adenovirus-mediated transduction of cells at the sites of laser photocoagulation in the rat eye.

PURPOSE: This study aimed to investigate the feasibility of recombinant adenovirus-mediated gene transfer into cells implicated in the development of choroidal neovascularization (CNV). METHODS: A rat model of CNV which used laser photocoagulation was developed. Gene delivery into the laser spots was investigated following subretinal injection of recombinant adenoviruses, AdRSVlacZ, AdCMVlacZ or AdCMVgfp. Immunohistochemical analysis was performed using a proliferating cell nuclear antigen antibody and a cytokeratin-specific antibody to identify the cell types transduced by the recombinant adenoviruses. RESULTS: At 7 days post-injection, lacZ expression was detected in 51.6 +/- 13.2% and 71.2 +/- 19.3% of laser spots in AdRSVlacZ- and AdCMVlacZ-injected eyes, respectively. By 28 days post-injection, lacZ expression was only present in AdCMVlacZ-injected eyes. In vivo fundus fluorescent photography of AdCMVgfp-injected eyes detected gfp expression in 79.9 +/- 12.7% and 35.6% +/- 19.7% of laser spots at 4 and 7 days post-injection, respectively. Although fundus fluorescent photography did not detect the gfp signal at 10 days post-injection, fluorescent microscopy revealed a gfp signal in 81.3 +/- 6.0% of laser spots. Immunohistochemical analysis detected retinal pigment epithelial (RPE) cells as the most predominant proliferating cell type in the laser spots, although several other proliferating cell types were also identified. X-gal staining showed that the majority of transduced cells were those present in the laser spots. CONCLUSIONS: It is proposed that following laser photocoagulation, proliferating RPE cells are susceptible to adenovirus-mediated gene delivery and that they may be suitable targets for the delivery of antiangiogenic factors by recombinant adenoviruses in order to inhibit developing CNV membranes.

Recombinant adenovirus-mediated gene delivery into the rat retinal pigment epithelium in vivo.

PURPOSE: The present paper describes changes following the subretinal injection of a recombinant replication-deficient adenovirus carrying the beta-galactosidase reporter gene construct into the rat retina. METHODS: Ad.RSV.betagal-mediated transduction of rat retinal pigment epithelium (RPE) cells in vitro and in vivo was examined following X-gal staining. RESULTS: There was a low level of beta-galactosidase expression in the RPE cells at 4 days postinjection. At 7 days postinjection, a strong transgene expression was present in RPE cells and the expression was maintained at 14 days postinjection. Except for the accumulation of cells at the site of the injection, the morphology of the rest of the retina remained normal. CONCLUSION: These results demonstrate that the RPE layer can be successfully targeted for gene delivery in the rat.

Determination of bisnafide, a novel bis-naphthalimide anticancer agent, in human plasma by high-performance liquid chromatography with UV detection.

A simple, specific, and sensitive high-performance liquid chromatographic (HPLC) assay utilizing ultraviolet (UV) detection for the determination of bisnafide in human plasma was developed, validated, and applied to plasma samples from patients undergoing cancer therapy. Plasma samples, containing an internal standard, XE842, were first deproteinized with 2.0 ml acetonitrile, and subsequently, 1.0 ml and pH 9 boric acid-potassium chloride-sodium hydroxide buffer (0.1 M) was added. To this mixture, 9.0 ml of ethyl ether was added then vortex mixed. Following centrifugation, the ether layer was back-extracted into 250 microliters of 0.1 M phosphoric acid, then removed by vacuum aspiration. A portion of the remaining acid layer was directly injected onto the HPLC. Bisnafide was quantified using a Shiseido Capcell Pak C8 HPLC column and ultraviolet detection (274 nm). The lower limit of quantification was 10 ng ml-1 using 1.0 ml plasma. The intraday precision (RSD) ranged from 2.7 to 8.6% over a concentration range of 10-1000 ng ml-1. The interday precision (RSD) ranged from 5.6 to 11.5%. Overall mean accuracy was +/- 5.2%. The drug was stable in frozen heparinized human plasma stored at -20 degrees C for at least 1 year and stable throughout at least two freeze-thaw cycles. This method was successfully utilized for quantifying plasma concentrations needed to study the clinical pharmacokinetics of bisnafide in patients undergoing cancer therapy.

Alpha/beta interferons increase host resistance to murine AIDS.

Murine AIDS (MAIDS) is caused by a defective retrovirus present in the LP-BM5 murine leukemia virus mixture. Strains of inbred mice differ in resistance to MAIDS development; some are susceptible (e.g., C57BL/6), while others are resistant (e.g., CBA and B10.BR). As an early block to viral replication in resistant mice has been demonstrated previously by PCR studies, we postulated that alpha/beta interferons (IFN-alpha/beta) may be involved in resistance to MAIDS. Susceptible C57BL/6 mice infected with LP-BM5 were treated with IFN-alpha/beta or Newcastle disease virus. Newcastle disease virus induces high endogenous IFN-alpha/beta production in mice. Both treatments delayed the development of MAIDS, as assessed by splenomegaly and T- and B-cell proliferation. In addition, an IFN-alpha/beta response was detected by reverse transcription-PCR and dot blotting 3, 6, and 9 h after LP-BM5 infection in resistant mice but not in susceptible mice. These results suggest that the ability to produce IFN-alpha/beta in response to LP-BM5 infection may contribute to host resistance to MAIDS.

Interferon-alpha inhibits erythropoietin-induced proliferation, but not differentiation, and restricts erythroleukemia development.

The immature erythroid cell line J2E responds to erythropoietin (Epo) by proliferating and terminally differentiating into hemoglobin-synthesizing red blood cells. These cells produce a rapid, fatal erythroleukemia in mice characterized by hepatosplenomegaly and severe anemia. The aim of this study was to investigate the effects of murine interferons-alpha (MuIFN-alpha) on J2E cells in vitro and in vivo. Here we show that in culture MuIFN-alpha inhibited the Epo-induced proliferation of J2E cells but did not interfere with differentiation. When mice with J2E erythroleukemias were treated with MuIFNs in vivo, an extension of their life span was observed. Moreover, numerous necrotic lesions of infiltrating leukemic cells were detected in the spleens of these mice. Finally, ex vivo treatment of leukemic bone marrow cells with Epo and MuIFNs delayed mortality even further. It was concluded that MuIFNs (1) suppressed the proliferation of J2E cells in vitro but did not affect Epo-induced differentiation, and (2) inhibited the progress of erythroleukemias, especially in combination with Epo.

A rapid fatal erythroleukemia caused by J2E cells can be treated ex vivo with erythropoietin.

The J2E cell line is an immature erythroid line which terminally differentiates in response to erythropoietin (epo), producing mature, hemoglobin-synthesizing red blood cells. We have shown that when these cells were injected into mice a rapid and fatal erythroleukemia developed with symptoms of severe anemia and hepatosplenomegaly. Southern blotting demonstrated that the leukemic cells were the introduced J2E cells. In addition to spleen and liver, the bone marrow was a major site of leukemic cell infiltration, and when grown in vitro leukemic cells from bone marrow remained responsive to erythropoietin. We reasoned, therefore, that treatment of mice with this hormone should alleviate the erythroleukemia, but regular injections of epo in vivo failed to arrest the progress of the disease. However, when bone marrow from leukemic mice was exposed continuously to the hormone ex vivo, before reinfusion into naive recipients, a marked extension in life span was observed. It was concluded that ex vivo epo treatment could be used therapeutically for J2E cell erythroleukemias.

Biological activities of recombinant murine interferons alpha 1 and alpha 4: large difference in antiproliferative effect.

The mature forms of two recombinant murine interferons alpha, alpha 1 and alpha 4, have been expressed in vitro using an established transcription and translation system. The relative specific antiviral activity, antiproliferative activity and the natural killer cell stimulating activity of both subtypes were compared in vitro. While the antiviral and natural killer cell stimulating activities of the 2 subtypes were similar, the relative antiproliferative activities varied markedly. On the basis of equal molar inputs, MuIFN-alpha 1 had less than 8% of the antiproliferative activity of MuIFN-alpha 4. This data shows that a large functional difference exists between these two subtypes which are known to be expressed at different levels in mouse L-cells in vitro.

Hepatic arterial embolization in patients with unresectable hepatocellular carcinoma--a randomized controlled trial.

A randomized controlled trial of hepatic arterial embolization was conducted in 63 consecutive patients who had unresectable but still embolizable hepatocellular carcinoma. Patients were randomized into three groups. Patients in group 1 received multiple hepatic arterial embolizations; patients in group 2 were given hepatic arterial embolization once, followed by monthly chemotherapy with high doses of 5-fluorouracil; and patients in group 3 received only monthly chemotherapy with high doses of 5-fluorouracil. Complete response was achieved in only 1 patient who received multiple hepatic arterial embolizations. Partial responses were observed in 13 patients (61.9%) in group 1, 10 patients (47.6%) in group 2, and 2 patients (9.5%) in group 3. The survival rates of patients in group 1 at the end of the ninth, 12th, 15th, 18th, and 21st months were 53.2%, 42.2%, 42.2%, 42.2%, and 42.2%, respectively, which were not significantly different from those of patients in group 2 but were better than the survival rates of patients in group 3. The results suggest that hepatic arterial embolization is an effective palliative treatment that prolongs survival of patients with unresectable hepatocellular carcinoma.