CD40 on human endothelial cells: inducibility by cytokines and functional regulation of adhesion molecule expression.

Cultured human umbilical vein endothelial cells (EC) constitutively express a low level of CD40 antigen as detected by monoclonal antibody binding and fluorescence flow cytometric quantitation. The level of expression on EC is increased about 3-fold following 24 h treatment with optimal concentrations of tumor necrosis factor, interleukin 1, interferon beta, or interferon gamma; both interferons show greater than additive induction of CD40 when combined with tumor necrosis factor or interleukin 1. Expression of CD40 increases within 8 h of cytokine treatment and continues to increase through 72 h. A trimeric form of recombinant murine CD40 ligand acts on human EC to increase expression of leukocyte adhesion molecules, including E-selectin, vascular cell adhesion molecule 1, and intercellular adhesion molecule 1. CD40 may be detected immunocytochemically on human microvascular EC in normal skin. We conclude that endothelial CD40 may play a role as a signaling receptor in the development of T-cell-mediated inflammatory reactions.

Sustained delivery of erythropoietin in mice by genetically modified skin fibroblasts.

We have examined whether the secretion of erythropoietin (Epo) from genetically modified cells could represent an alternative to repeated injections of the recombinant hormone for treating chronic anemias responsive to Epo. Primary mouse skin fibroblasts were transduced with a retroviral vector in which the murine Epo cDNA is expressed under the control of the murine phosphoglycerate kinase promoter. "Neo-organs" containing the genetically modified fibroblasts embedded into collagen lattices were implanted into the peritoneal cavity of mice. Increased hematocrit (> 80%) and elevated serum Epo concentration (ranging from 60 to 408 milliunits/ml) were observed in recipient animals over a 10-month observation period. Hematocrit values measured in recipient mice varied according to the number of implanted Epo-secreting fibroblasts (ranging from 2.5 to 20 x 10(6)). The implantation of neo-organs containing Epo-secreting fibroblasts appeared, therefore, as a convenient method to achieve permanent in vivo delivery of the hormone. We estimated that the biological efficacy of the approach may be relevant for the treatment of human hemoglobinopathies.

Efficient in vivo antitumor effect of an immunotoxin based on ribotoxin α-sarcin in nude mice bearing human colorectal cancer xenografts

Tagging of RNases, such as the ribotoxin α-sarcin, with the variable domains of antibodies directed to surface antigens that are selectively expressed on tumor cells endows cellular specificity to their cytotoxic action. A recombinant single-chain immunotoxin based on the ribotoxin α-sarcin (IMTXA33αS), produced in the generally regarded as safe (GRAS) yeast Pichia pastoris, has been recently described as a promising candidate for the treatment of colorectal cancer cells expressing the glycoprotein A33 (GPA33) antigen, due to its high specific and effective cytotoxic effect on in vitro assays against targeted cells. Here we report the in vivo antitumor effectiveness of this immunotoxin on nude mice bearing GPA33-positive human colon cancer xenografts. Two sets of independent assays were performed, including three experimental groups: control (PBS) and treatment with two different doses of immunotoxin (50 or 100 μg/ injection) (n = 8). Intraperitoneal administration of IMTXA33αS resulted in significant dose-dependent tumor growth inhibition. In addition, the remaining tumors excised from immunotoxin-treated mice showed absence of the GPA33 antigen and a clear inhibition of angiogenesis and proliferative capacity. No signs of immunotoxin-induced pathological changes were observed from specimens tissues.Overall these results show efficient and selective cytotoxic action on tumor xenografts, combined with the lack of severe side effects, suggesting that IMTXA33αS is a potential therapeutic agent against colorectal cancer.

Human iPSC derived disease model of MERTK-associated retinitis pigmentosa

Retinitis pigmentosa (RP) represents a genetically heterogeneous group of retinal dystrophies affecting mainly the rod photoreceptors and in some instances also the retinal pigment epithelium (RPE) cells of the retina. Clinical symptoms and disease progression leading to moderate to severe loss of vision are well established and despite significant progress in the identification of causative genes, the disease pathology remains unclear. Lack of this understanding has so far hindered development of effective therapies. Here we report successful generation of human induced pluripotent stem cells (iPSC) from skin fibroblasts of a patient harboring a novel Ser331Cysfs*5 mutation in the MERTK gene. The patient was diagnosed with an early onset and severe form of autosomal recessive RP (arRP). Upon differentiation of these iPSC towards RPE, patient-specific RPE cells exhibited defective phagocytosis, a characteristic phenotype of MERTK deficiency observed in human patients and animal models. Thus we have created a faithful cellular model of arRP incorporating the human genetic background which will allow us to investigate in detail the disease mechanism, explore screening of a variety of therapeutic compounds/reagents and design either combined cell and gene- based therapies or independent approaches.

Severe Cutaneous Leishmaniasis in a Human Immunodeficiency Virus Patient Coinfected with Leishmania braziliensis and Its Endosymbiotic Virus.

Leishmaniaparasites cause a broad range of disease, with cutaneous afflictions being, by far, the most prevalent. Variations in disease severity and symptomatic spectrum are mostly associated to parasite species. One risk factor for the severity and emergence of leishmaniasis is immunosuppression, usually arising by coinfection of the patient with human immunodeficiency virus (HIV). Interestingly, several species ofLeishmaniahave been shown to bear an endogenous cytoplasmic dsRNA virus (LRV) of theTotiviridaefamily, and recently we correlated the presence of LRV1 withinLeishmaniaparasites to an exacerbation murine leishmaniasis and with an elevated frequency of drug treatment failures in humans. This raises the possibility of further exacerbation of leishmaniasis in the presence of both viruses, and here we report a case of cutaneous leishmaniasis caused byLeishmania braziliensisbearing LRV1 with aggressive pathogenesis in an HIV patient. LRV1 was isolated and partially sequenced from skin and nasal lesions. Genetic identity of both sequences reinforced the assumption that nasal parasites originate from primary skin lesions. Surprisingly, combined antiretroviral therapy did not impact the devolution ofLeishmaniainfection. TheLeishmaniainfection was successfully treated through administration of liposomal amphotericin B.

Current cancer research [on] etiology, epidemiology, and biology of melanomas and other skin cancers.

Prepared for the ICRDB Program by the Current Cancer Research Project Analysis Center.

Human physiology /

v. 1-2 edited by Dr. M. Camis; v. 3-4, by Gordon M. Holmes; v.5, by M.S. Pembrey.

Morris's Human anatomy; a complete systematic treatise by English and American authors,

pt. 1. General morphogeny. Osteology. Articulations.--pt. 2. The musculature. The organs of circulation. The lymphatics.--pt. 3. The nervous system. Organs of special sense.--pt. 4. The organs of digestion. The respitory organs. The urinary and reproductive organs. The ductless glands. The skin and mammary gland.--pt.5. Surgical and topographical anatomy.

Hookworm aspartic protease, Na-APR-2, cleaves human hemoglobin and serum proteins in a host-specific fashion

Hookworms are voracious blood-feeders. The cloning and functional expression of an aspartic protease, Na-APR-2, from the human hookworm Necator americanus are described here. Na-APR-2 is more similar to a family of nematode-specific, aspartic proteases than it is to cathepsin D or pepsin, and the term nemepsins for members of this family of nematode-specific hydrolases is proposed. Na-apr-2 mRNA was detected in blood-feeding, developmental stages only of N. americanus, and the protease was expressed in the intestinal lumen, amphids, and excretory glands. Recombinant Na-APR-2 cleaved human hemoglobin (Hb) and serum proteins almost twice as efficiently as the orthologous substrates from the nonpermissive dog host. Moreover, only 25% of the Na-APR-2 cleavage sites within human Hb were shared with those generated by the related N. americanus cathepsin D, Na-APR-1. Antiserum against Na-APR-2 inhibited migration of 50% of third-stage N. americanus larvae through skin, which suggests that aspartic proteases might be effective vaccines against human hookworm disease.

Activation of the cAMP pathway by variant human MC1R alleles expressed in HEK and in melanoma cells

alpha-Melanocyte-stimulating hormone (alpha-MSH) activates the melanocortin-1 receptor (MC1R) on melanocytes to promote a switch from red/yellow pheomelanin synthesis to darker eumelanins via positive coupling to adenylate cyclase. The human MC1R locus is highly polymorphic with the specific variants associated with red hair and fair skin (RHC phenotype) postulated to be loss-of-function receptors. We have examined the ability of MC1R variants to activate the cAMP pathway in stably transfected REK293 cells. The RHC associated variants, Arg151Cys, Arg160Trp and Asp294His, demonstrated agonist-mediated increases in cAMP and phosphorylation of cAMP-responsive element-binding protein (CREB). Whereas the Asp294His variant showed severely impaired functional responses, the Arg151Cys and Arg160Trp variants retained considerable signaling capacity. Melanoma cells homozygous for either the Arg151Cys variant or consensus sequence both elicited CREB phosphorylation in response to alpha-MSH in the presence of IBMX. The common RHC alleles, Arg151Cys, Arg160Trp and Asp294His, are neither complete loss-of-function receptors nor are they functionally equivalent. (c) 2005 Elsevier Inc. All rights reserved.

Role of dietary factors in the development of basal cell cancer and squamous cell cancer of the skin

The role of dietary factors in the development of skin cancer has been investigated for many years; however, the results of epidemiologic studies have not been systematically reviewed. This article reviews human studies of basal cell cancer (BCC) and squamous cell cancer (SCC) and includes all studies identified in the published scientific literature investigating dietary exposure to fats, retinol, carotenoids, vitamin E, vitamin Q and selenium. A total of 26 studies were critically reviewed according to study design and quality of the epidemiologic evidence. Overall, the evidence suggests a positive relationship between fat intake and BCC and SCC, an inconsistent association for retinol, and little relation between beta-carotene and BCC or SCC development. There is insufficient evidence on which to make a judgment about an association of other carotenoids with skin cancer. The evidence for associations between vitamin E, vitamin C, and selenium and both BCC and SCC is weak. Many of the existing studies contain limitations, however, and further well-designed and implemented studies are required to clarify the role of diet in skin cancer. Additionally, the role of other dietary factors, such as flavonoids and other polyphenols, which have been implicated in skin cancer development in animal models, needs to be investigated.

Pathways to improving skin regeneration

A significant proportion of the human population suffers from some form of skin disorder, whether it be from burn injury or inherited skin anomalies. The ideal treatment for skin disorders would be to regrow skin tissue from stem cells residing in the individual patient's skin. Locating these adult stem cells and elucidating the molecules involved in orchestrating the production of new skin cells are important steps in devising more-efficient methods of skin production and wound healing via the ex vivo expansion of patient keratinocytes in culture. This review focuses on the structure of the skin, the identification of skin stem cells, and the role of Notch, Wnt and Hedgehog signalling cascades in regulating the fate of epidermal stem cells. © 2005 Cambridge University Press.

Numerical modeling of 11.1 T MRI of a human head using MoM/FDTD methods

In a recent study, severe distortions in the proton images of an excised, fixed, human brain in an 11.1 Tesla/40 cm MR instrument have been observed, and the effect modeled on phantom images using a finite difference time domain (FDTD) model. in the present study, we extend these simulations to that of a complete human head, employing a hybrid FDTD and method of moments (MoM) approach, which provides a validated method for simulating biological samples in coil structures. The effect of fixative on the image distortions is explored. importantly, temperature distributions within the head are also simulated using a bioheat method based on parameters derived from the electromagnetic simulations. The MoM/FDTD simulations confirm that the transverse magnetic field (B,) from a ReCav resonator exhibits good homogeneity in air but strong inhomogeneity when loaded with the head with or without fixative. The fixative serves to increase the distortions, but they are still significant for the in vivo simulations. The simulated signal intensity (SI) distribution within the sample confirm the distortions in the experimental images are caused by the complex interactions of the incident electromagnetic fields with tissue, which is heterogeneous in terms of conductivity and permittivity. The temperature distribution is likewise heterogeneous, raising concerns regarding hot spot generation in the sample that may exceed acceptable levels in future in vivo studies. As human imaging at 11.1 T is some time away, simulations are important in terms of predicting potential safety issues as well as evaluating practical concerns about the quality of images. Simulation on a whole human head at 11.1 T implies the wave behavior presents significant engineering challenges for ultra-high-field (UHF) MRI. Novel strategies will have to be employed in imaging technique and resonator design for UHF MRI to achieve the theoretical signal-to-noise ratio (SNR) improvements it offers over lower field systems. (C) 2005 Wiley Periodicals, Inc.

Clinical outcomes from skin screening clinics within a community-based melanoma screening program

Background : Within a randomized trial of population screening for melanoma, primary care physicians conducted whole-body skin examinations and referred all patients with suspect lesions to their own doctor for further treatment. Objective: Our aim was to describe characteristics of skin screening participants, clinical screening diagnoses, management following referral, and specificity and yield of screening examinations. Methods: Information collected from consent forms, referral forms, and histopathological reports of lesions that had been excised or undergone biopsy was analyzed by means of descriptive statistics. Results: A total of 16,383 whole-body skin examinations resulted in 2302 referrals (14.1% overall; 15.5% men, 18.2% >= 50 years of age) for 4129 suspect lesions (including 222 suspected melanoma, 1101 suspected basal cell carcinomas [BCCs], 265 suspected squamous cell carcinomas [SCCs]). Histopathologic results were available for 94.8% of 1417 lesions excised and confirmed 33 melanomas (23 in men; 24 in participants ? 50 years of age), 259 BCCs, and 97 SCCs. The probability of detecting skin cancer of any type within the program was 2.4%. The estimated specificity of whole-body skin examinations for melanoma was 86.1% (95% confidence interval = 85.6-86.6). The positive predictive value (number of confirmed/number of lesions excised or biopsied x 100) for melanoma was 2.5%, 19.3% for BCC, and 7.2% for SCC (overall positive predictive value for skin cancer, 28.9%). Limitations: Follow-up of participants with a negative screening examination has not been conducted for the present investigation. Conclusions: The rate of skin cancer detected per 100 patients screened was higher than previously reported and men and attendees older than 50 years more frequently received a referral and diagnosis of melanoma. The specificity for detection of melanoma through whole-body skin examination by a primary care physician was comparable to that of other screening tests, including mammography.

Diversity of pigmentation in cultured human melanocytes is due to differences in the type as well as quantity of melanin

Cultured human melanocytes differ tremendously in visual pigmentation, and recapitulate the pigmentary phenotype of the donor's skin. This diversity arises from variation in type as well as quantity of melanin produced. Here, we measured contents of eumelanin (EM) and pheomelanin (PM) in 60 primary human melanocyte cultures (51 neonatal and nine adults), and correlated some of these values with the respective activity and protein levels of tyrosinase, and the melanocortin-1 receptor (MC1R) genotype. Melanocytes were classified into four phenotypes (L, L+, D, D+) as depicted by visual pigmentation using light microscopy, and by the pigmentary phenotype of the donor's skin. There were large differences in total melanin (TM) and EM, which increased progressively for L, L+, D and D+ melanocytes. TM content, the sum of EM and PM, showed a good correlation with TM measured spectrophotometrically, and with the activity and protein levels of tyrosinase. Log EM/PM ratio did not correlate with MC1R genotype. We conclude that: (i) EM consistently correlates with the visual phenotype; (ii) lighter melanocytes tend to be more pheomelanic in composition than darker melanocytes; (iii) in adult melanocyte cultures, EM correlates with the ethnic background of the donors (African-American > Indian > Caucasian); and (iv) MC1R loss-of-function mutations do not necessarily alter the phenotype of cultured melanocytes.