AAV Gene Therapy for MPS1-associated Corneal Blindness

Although cord blood transplantation has significantly extended the lifespan of mucopolysaccharidosis type 1 (MPS1) patients, over 95% manifest cornea clouding with about 50% progressing to blindness. As corneal transplants are met with high rejection rates in MPS1 children, there remains no treatment to prevent blindness or restore vision in MPS1 children. Since MPS1 is caused by mutations in idua, which encodes alpha-L-iduronidase, a gene addition strategy to prevent, and potentially reverse, MPS1-associated corneal blindness was investigated. Initially, a codon optimized idua cDNA expression cassette (opt-IDUA) was validated for IDUA production and function following adeno-associated virus (AAV) vector transduction of MPS1 patient fibroblasts. Then, an AAV serotype evaluation in human cornea explants identified an AAV8 and 9 chimeric capsid (8G9) as most efficient for transduction. AAV8G9-opt-IDUA administered to human corneas via intrastromal injection demonstrated widespread transduction, which included cells that naturally produce IDUA, and resulted in a >10-fold supraphysiological increase in IDUA activity. No significant apoptosis related to AAV vectors or IDUA was observed under any conditions in both human corneas and MPS1 patient fibroblasts. The collective preclinical data demonstrate safe and efficient IDUA delivery to human corneas, which may prevent and potentially reverse MPS1-associated cornea blindness.

Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells

Mesenchymal stromal cells (MSC) constitutively express low levels of human leukocyte antigen-G (HLA-G), which has been shown to contribute to their immunomodulatory and anti-inflammatory properties. Here, we hypothesized that overexpression of HLA-G on bone marrow-derived MSC would improve their immunomodulatory function, thus increasing their therapeutic potential. Therefore, we investigated which gene transfer system is best suited for delivering this molecule while maintaining its immunomodulatory effects. We performed a side-by-side comparison between three nonviral plasmid-based platforms (pmax-HLA-G1; MC-HLA-G1; pEP-HLA-G1) and a viral system (Lv-HLA-G1) using gene transfer parameters that yielded similar levels of HLA-G1-expressing MSC. Natural killer (NK) cell–mediated lysis assays and T cell proliferation assays showed that MSC modified with the HLA-G1 expressing viral vector had significantly lower susceptibility to NK-lysis and significantly reduced T cell proliferation when compared to nonmodified cells or MSC modified with plasmid. We also show that, in plasmid-modified MSC, an increase in Toll-like receptor (TLR)9 expression is the mechanism responsible for the abrogation of HLA-G1’s immunomodulatory effect. Although MSC can be efficiently modified to overexpress HLA-G1 using viral and nonviral strategies, only viral-based delivery of HLA-G1 is suitable for improvement of MSC’s immunomodulatory properties.

The first 3 years of national bowel cancer screening at a single UK tertiary centre

AIM

St Mark's Bowel Cancer Screening Centre commenced screening in October 2006 as a contributor to the national programme. The first 35 months' experience is reported.

METHOD

Individuals with a positive faecal occult blood test (FOBT) were offered colonoscopy or alternatives if they had significant comorbidity. All screening data were collected prospectively.

RESULTS

Of the 98 815 FOBT kits issued, 42 523 were returned (43% uptake; 20.79% men). In total, 1339/1488 (90%) FOBT-positive participants attended the nurse clinic (57% men). Of these, 1057 had an index colonoscopy, 115 had a computed tomography colonoscopy (CTC) and eight had a flexible sigmoidoscopy. Five hundred and seventeen (44%) procedures were 'normal' (no polyps/cancers). Eighty (6%) individuals had colorectal cancer. The polyp detection rate in index procedures, including colonoscopy, CTC and flexible sigmoidoscopy, was 50%. The adenoma detection rate of all colonoscopies was 62.8%. The median polyp size was 5 (1-80) mm. In total, 1200 colonoscopies were performed by five accredited colonoscopists (96% completion rate). There were 13 (1%) adverse events with < 1 in 500 patients undergoing polypectomy requiring a transfusion. There was one 30-day postsurgical mortality, one perforation and no colonoscopy-related mortality. Almost all 39/40 (97%) patients in the BCS programme felt that the findings were adequately explained compared with 21/32 (64%) elective patients (P < 0.001) within the same unit.

CONCLUSIONS

At this bowel cancer screening single centre, colonoscopy completion rates were high (unadjusted caecal intubation rate of 96%) and complication rates were low. In contrast to other published data, the uptake and cancer-detection rates were lower.

THE EFFECTS OF INTRAVENOUS INJECTIONS OF DICHLOROETHYLSULFIDE IN RABBITS, WITH SPECIAL REFERENCE TO ITS LEUCOTOXIC ACTION

1. The lethal dose of dichloroethylsulfide (distilled from a German yellow cross shell), when injected intravenously into rabbits is from 0.005 to 0.01 gm. per kilo. 2. Rabbits dying within 24 hours showed extensive hemorrhages, and edema of the lungs. 3. Severe lesions of the intestinal tract were present in about one-third of the rabbits. 4. Dichloroethylsulfide injected intravenously is specifically poisonous for the hematopoietic tissues. Severe lesions are caused in the bone marrow, and the number of circulating leucocytes is markedly deminished. In animals surviving the injection regeneration occurs. The granular cells of the bone marrow seem to be more sensitive than the lymphoid cells and the erythrocytes. 5. The effect upon the blood and hematopoietic tissues is not due to the admixture of nitrobenzene or chlorobenzene in the shell filling. Injection of these substances in animals in amounts many times greater than the total dose of dichloroethylsulfide used produced no changes in the blood picture, and the subsequent injection of dichloroethylsulfide free from these solvents produced a typical reaction.

Use of multidetector-row computed tomographic colonography before flexible sigmoidoscopy in the investigation of rectal bleeding

Selective colonography may reduce need for colonoscopy

From fixed to individual dosing in growth hormone-deficient adults

Initial research studies of growth hormone (GH) replacement in adults employed what is now considered to be high doses of GH, from 12 to 25 microg/kg per day. While the beneficial effects of GH were demonstrated, there was a considerable incidence of side effects, most commonly edema and arthralgia. These side effects abated with a dose reduction. More recently, the Growth Hormone Research Society recommended initiating GH replacement at a dose of 0.3 mg/day irrespective of total or ideal body weight. The United States Food and Drug Administration approved pharmaceutical company package inserts that recommended beginning with a dose of 6 microg/kg per day with a maximum dose of 25 microg/kg per day and limiting the maximal dose to 12.5 microg/kg per day in adults over the age of 35 years. These should be considered as guidelines.

Peptide T blocks GP120/CCR5 chemokine receptor-mediated chemotaxis

We previously reported that certain short gp120 V2 region peptides homologous to vasaoactive intestinal peptide (VIP), such as "peptide T," were potent inhibitors of gp120 binding, infectivity, and neurotoxicity. The present study shows that synthetic V2-region-derived peptides have potent intrinsic chemotaxis agonist activity for human monocytes and also act as antagonists of high-affinity (0.1 pM) gp120-mediated monocyte chemotaxis. Selectivity is shown in that peptide T is more potent at suppressing M-tropic than T-tropic gp120 chemotaxis. Peptide T was also able to suppress monocyte chemotaxis to MIP-1beta, a chemokine with selectivity for CCR5 chemokine receptors, while chemotaxis of the more promiscuous ligand RANTES was not inhibited, nor was chemotaxis mediated by SDF-1alpha. In order to determine if peptide T mediated its gp120 antagonistic effects via modulation of CCR5 receptors, RANTES chemotaxis was studied using a CCR5 receptor-transfected HOS cell line. In this case, RANTES chemotaxis was potently inhibited by V2-region-derived short peptides. Peptide T also partially suppressed (125)I-MIP1-beta binding to human monocytes, suggesting action at a subset of MIP1-beta receptors. The V2 region of gp120 thus contains a potent receptor binding domain and synthetic peptides derived from this region modulate CCR5 chemokine receptor chemotactic signaling caused by either gp120 or chemokine ligands. The results have therapeutic implications and may explain recent clinical improvements, in that HIV/gp120 actions at CCR5 receptors, such as occur in the brain or early infection, would be susceptible to peptide T inhibition.

Life-threatening airway obstruction from rattlesnake bite to the tongue

We describe the case of a 41-year-old man who suffered a bite to the tongue from the Western Diamondback rattlesnake (C atrox). Life-threatening obstruction of his upper airway secondary to massive edema of the tongue and other soft tissue structures quickly followed envenomation. Nasotracheal intubation, IV antivenin, and supportive care resulted in complete recovery with no permanent deficits. Rattlesnake bites to the tongue are rare and pose an unusual cause of airway obstruction.

Human pancreatic tumor GH-releasing factor

Within the past year, three similar peptides with specific growth hormone (GH) releasing effects have been extracted from human tissue, identified, and synthesized. Human pancreatic tumor GH releasing factor (I-40)-OH (hpGRF-40) was the sole hpGRF isolated from the pancreatic tumor of a patient in Charlottesville and was the predominant peptide isolated from the pancreatic tumor of a patient in Lyon. The Lyon tumor also contained hpGRF(1-37)-OH and hpGRF(1-44)-NH2. Both immunological and biochemical data suggest that hpGRF-40 and hpGRF-44 are present in the human hypothalamus and may be the human GH releasing hormone(s) (GHRH). In cultures of rat pituitary cells, hpGRF stimulates GH but affects neither basal and dopamine-inhibited prolactin release nor basal and gonadotropin releasing hormone (GnRH)-stimulated luteinizing hormone (LH) release. hpGRF stimulates cyclic AMP production within seconds, an effect which is blocked by somatostatin. In contrast, while hpGRF stimulates phosphatidylinositol turnover in the pituitary, the effect is not inhibited by somatostatin. In the human, hpGRF-40 (1 microgram/kg) given intravenously (i.v.) stimulates GH release within 5 minutes. hpGRF-40 does not elevate serum prolactin levels, thyrotropin (TSH), LH, or corticotropin (measured indirectly through plasma cortisol), or blood glucose or plasma concentrations of insulin, glucagon, pancreatic polypeptide, cholecystokinin, gastrin, gastric inhibitory peptide, motilin, or somatostatin. When graded doses of hpGRF (0.1-10 micrograms/kg) are given i.v., no differences are noted in the maximal levels of serum GH achieved.(ABSTRACT TRUNCATED AT 250 WORDS)

Hydrogen sulphide-positive strains of Escherichia coli from swine

Thirty-two H2S-positive strains of Escherichia coli, isolated from the caecal contents or mesenteric lymph nodes or both of 60 apparently healthy pigs, were characterized. Eighteen different serotypes and 18 different fermentative types were found. During conjugation with E. coli K12, four strains transferred their Hys plasmids linked to Raf, and another transferred Hys associated with the Tc determinant. All Hys-Raf plasmids belong to incompatibility group FI, whilst Tc-Hys is an Fi- plasmid.