Nerve growth factor prevents both neuroretinal programmed cell death and capillary pathology in experimental diabetes.

BACKGROUND: Chronic diabetes causes structural changes in the retinal capillaries of nearly all patients with a disease duration of more than 15 years. Acellular occluded vessels cause hypoxia, which stimulates sight-threatening abnormal angiogenesis in 50% of all type I diabetic patients. The mechanism by which diabetes produces acellular retinal capillaries is unknown. MATERIALS AND METHODS: In this study, evidence of programmed cell death (PCD) was sought in the retinas of early diabetic rats, and the effect of nerve growth factor (NGF) on PCD and capillary morphology was evaluated. RESULTS: Diabetes induced PCD primarily in retinal ganglion cells (RGC) and Muller cells. This was associated with a transdifferentiation of Muller cells into an injury-associated glial fibrillary acidic protein (GFAP)-expressing phenotype, and an up-regulation of the low-affinity NGF receptor p75NGFR on both RGC and Muller cells. NGF treatment of diabetic rats prevented both early PCD in RGC and Muller cells, and the development of pericyte loss and acellular occluded capillaries. CONCLUSIONS: These data provide new insight into the mechanism of diabetic retinal vascular damage, and suggest that NGF or other neurotrophic factors may have potential as therapeutic agents for the prevention of human diabetic retinopathy.     

Isolation of a maltase structural gene from Saccharomyces carlsbergensis.

The maltase structural gene MAL6 of the yeast Saccharomyces carlsbergensis has been cloned by transformation of a maltose nonfermenting recipient strain with autonomously replicating chimeric recombinant plasmids. One recombinant plasmid, pMAL26, was shown by positive hybridization translation, as well as by Southern and Northern blot experiments, to carry the MAL6 structural gene.     

Utilization of milk energy by suckling mink kits

A total of 36 mink dams and their litters of 3, 6 or 9 kits were used for determination of milk intake of the suckling young by means of deuterium dilution technique, and chemical composition of milk and of kit bodies. Measurements were performed during lactation weeks 1?–?4, each week with 3 dams with each litter size. Milk intake was determined over a 48?h measurement period, and by the end of this milk samples were collected and 2 kits (litters of 6 and 9) or 1 kit per litter (litters of 3) were killed for body chemical composition. Based on the results, different models were applied for calculation of the energetic efficiency of milk. Dam milk yield increased steadily from week 1 until week 3 but only slightly from week 3 to 4. The increase declined with increasing litter size, and for dams suckling 9 kits the increment from week 3 to week 4 was only 2?g. The dry matter content of milk increased significantly as lactation progressed, being reflected in crude protein increasing from 6.9% in lactation week 1 to 8.1% in week 4. Milk fat increased concomitantly from 5.6% to 8.0%. In kit bodies, crude protein content increased from 9.4% in week 1 to about 12% in weeks 3 and 4. Body fat content increased from week 1 (4.1%) to week 3 (8.4%) and then declined in week 4 (7.1%). Animals suckled in litters of 3 kits had the highest milk intake and live weight and kits suckled in litters of 9 had the lowest milk intake, live weight and daily gain. In terms of milk intake per g gain kits in litters of 6 were the most efficient, with 4.1?g milk per g body gain. The metabolizable energy requirement for maintenance (MEm) was estimated to 448 kJ/kg^0.75 and the efficiency of utilization of ME for body gain (k_g) to 0.67, the estimates being higher (MEm) or in good agreement with previous findings (k_g) in suckling mink kits.     

Combination vascular delivery of herpes simplex oncolytic viruses and amplicon mediated cytokine gene transfer is effective therapy for experimental liver cancer

BACKGROUND: Herpes simplex type I (HSV)-based vectors have been used experimentally for suicide gene therapy, immunomodulatory gene delivery, and direct oncolytic therapy. The current study utilizes the novel concept of regional delivery of an oncolytic virus in combination with or serving as the helper virus for packaging herpes-based amplicon vectors carrying a cytokine transgene, with the goal of identifying if this combination is more efficacious than either modality alone. MATERIALS AND METHODS: A replication competent oncolytic HSV (G207) and a replication incompetent HSV amplicon carrying the gene for the immunomodulatory cytokine IL-2 (HSV-IL2) were tested in murine syngeneic colorectal carcinoma and in rat hepatocellular carcinoma models. Liver tumors were treated with vascular delivery of (1) phosphate-buffered saline (PBS), (2) G207, (3) HSV-IL2, (4) G207 and HSV-IL2 mixed in combination (mG207/HSV- IL2), and (5) G207 as the helper virus for packaging the construct HSV-IL2 (pG207/HSV-IL2). RESULTS: Tumor burden was significantly reduced in all treatment groups in both rats and mice treated with high-dose G207, HSV-IL2, or both (p < 0.02). When a low dose of virus was used in mice, anti-tumor efficacy was improved by use of G207 and HSV-IL2 in combination or with HSV-IL2 packaged by G207 (p < 0.001). This improvement was abolished when CD4(+) and CD8(+) lymphocytes were depleted, implying that the enhanced anti-tumor response to low-dose combined therapy is immune mediated. CONCLUSIONS: Vascular regional delivery of oncolytic and amplicon HSV vectors can be used to induce improved anti-tumor efficacy by combining oncolytic and immunostimulatory strategies.     

Polymorphism of alpha 1-antitrypsin in North American species of Canis

alpha 1-Antitrypsin (A1AT) is a major protease inhibitor present in all mammalian sera that have thus far been investigated. A1AT is also highly polymorphic and is therefore a useful genetic marker. Previously reported A1AT polymorphism in domestic dogs consisted of two alleles designated as PiM and PiS which exhibited frequencies of 0.72 and 0.28, respectively, in a group of randomly collected mongrel dogs. North American species of Canis, which included gray wolves (n = 29), Mexican wolves (n = 20), coyotes (n = 24), wolf-dog crosses (n = 9), and red wolves (n = 27) were tested for A1AT polymorphism. A1AT phenotypes were determined by isoelectric focusing, followed by direct immunoblotting using a specific antiserum. A1AT concentrations were determined by radial immunodiffusion. Concentrations of A1AT were similar to those found in domestic dogs (2.26 +/- 0.3, +/- SD mg/ml, +/- SD) and tended to be higher in females than in males, possibly indicating that A1AT may be hormonally influenced in females. Three phenotypic band patterns were observed (M, MS, S). The allele frequencies for domestic dogs and gray wolves were very similar, 0.72 and 0.67 for PiM and 0.28 and 0.33 for PiS, respectively. The Mexican wolves had a significantly lower frequency of PiS = 0.10. Coyotes and red wolves were all found to be monomorphic for the PiS allele and were indistinguishable from each other in that respect.     

Human dendritic cells transduced with herpes simplex virus amplicons encoding human immunodeficiency virus type 1 (HIV-1) gp120 elicit adaptive immune responses from human cells engrafted into NOD/SCID mice and confer partial protection against HIV-1 challenge

Small-animal models are needed to test human immunodeficiency virus (HIV) vaccine efficacy following viral challenge. To this end, we examined HIV-1-specific immune responses following immunization of nonobese diabetic-severe combined immunodeficient mice that were repopulated with human peripheral blood lymphocytes (hu-PBL-NOD/SCID mice). Autologous dendritic cells (DC) were transduced ex vivo with replication-defective, helper virus-free, herpes simplex virus type 1 (HSV-1) amplicons that expressed HIV-1 gp120 and were then injected into the hu-PBL-NOD/SCID mice. This resulted in primary HIV-1-specific humoral and cellular immune responses. Serum samples from vaccinated animals contained human immunoglobulin G that reacted with HIV-1 Env proteins by enzyme-linked immunosorbent assay and neutralized the infectivity of HIV-1 LAI and ADA strains. T cells isolated from the mice responded to viral antigens by producing gamma interferon when analyzed by enzyme-linked immunospot assay. Importantly, exposure of the vaccinated animals to infectious HIV-1 demonstrated partial protection against infectious HIV-1 challenge. This was reflected by a reduction in HIV-1(ADA) and by protection of the engrafted human CD4(+) T lymphocytes against HIV-1(LAI)-induced cytotoxicity. These data demonstrate that transduction of DC by HSV amplicon vectors expressing HIV-1 gp120 induce virus-specific immune responses in hu-PBL-NOD/SCID mice. This mouse model may be a useful tool to evaluate human immune responses and protection against viral infection following vaccination.     

Activity-dependent α-Cleavage of Nectin-1 Is Mediated by A Disintegrin and Metalloprotease 10 (ADAM10)

Nectin-1 is known to undergo ectodomain shedding by α-secretase and subsequent proteolytic processing by γ-secretase. How secretase-mediated cleavage of nectin-1 is regulated in neuronal cells and how nectin-1 cleavage affects synaptic adhesion is poorly understood. We have investigated α-and γ-secretase-mediated processing of nectin-1 in primary cortical neurons and identified which protease acts as a α-secretase. We report here that NMDA receptor activation, but not stimulation of AMPA or metabotropic glutamate receptors, resulted in robust α- and γ-secretase cleavage of nectin-1 in mature cortical neurons. Cleavage of nectin-1 required influx of Ca²⁺ through the NMDA receptor, and activation of calmodulin, but was not dependent on calcium/calmodulin-dependent protein kinase II (CaMKII) activation. We found that ADAM10 is the major secretase responsible for nectin-1 ectodomain cleavage in neurons and the brain. These observations suggest that α- and γ-secretase processing of nectin-1 is a Ca²⁺/calmodulin-regulated event that occurs under conditions of activity-dependent synaptic plasticity and ADAM10 and γ-secretase are responsible for these cleavage events.     

Fluctuating asymmetry in bank vole populations (Rodentia, Arvicolinae) reflects stress caused by landscape fragmentation in the Mont-Saint-Michel Bay

In intensively farmed, reclaimed areas (polders) of Mont-St-Michel Bay, France, bank voles ( Clethrionomys glareolus ) live in fragmented hedgerows, where populations are small and dispersal rates and genetic diversity are low. These small populations are likely to have been exposed to potential environmental and/or genetic stress. The sensitivity of development to stress can be measured by fluctuating asymmetry (FA). FA was calculated for three samples from a disturbed area and one sample from an adjacent, more connected and undisturbed landscape. Size FA was estimated from 16 measurements of the skull and teeth whilst shape asymmetry was estimated from the skull alone. Bank voles in fragmented hedgerows of the disturbed area had a higher degree of FA than bank voles from the more extensive and more connected hedges of the undisturbed area. These results were confirmed by the study of shape asymmetry, body mass and centroid size of the skull. There were no differences in FA between the three disturbed area samples. We conclude that FA does not reveal differences in the development of bank voles living in isolation under different local conditions in the various parts of the disturbed area. However, FA may allow differentiation between populations from greatly contrasting landscapes.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80, 37–44.