Microphthalmia-associated transcription factor suppresses invasion by reducing intracellular GTP pools.

Melanoma progression is associated with increased invasion and, often, decreased levels of microphthalmia-associated transcription factor (MITF). Accordingly, downregulation of MITF induces invasion in melanoma cells; however, little is known about the underlying mechanisms. Here, we report for the first time that depletion of MITF results in elevation of intracellular GTP levels and increased amounts of active (GTP-bound) RAC1, RHO-A and RHO-C. Concomitantly, MITF-depleted cells display larger number of invadopodia and increased invasion. We further demonstrate that the gene for guanosine monophosphate reductase (GMPR) is a direct MITF target, and that the partial repression of GMPR accounts mostly for the above phenotypes in MITF-depleted cells. Reciprocally, transactivation of GMPR is required for MITF-dependent suppression of melanoma cell invasion, tumorigenicity and lung colonization. Moreover, loss of GMPR accompanies downregulation of MITF in vemurafenib-resistant BRAFV600E-melanoma cells and underlies the increased invasion in these cells. Our data uncover novel mechanisms linking MITF-dependent inhibition of invasion to suppression of guanylate metabolism.

[Adaptive immune response and associated trigger factors in atopic dermatitis]. / Adaptive Immunantworten und damit verbundene Triggerfaktoren bei atopischer Dermatitis.

Due to a broad variety of extrinsic trigger factors, patients with atopic dermatitis (AD) are characterized by complex response mechanisms of the adaptive immune system. Notably, skin colonization with Staphylococcus aureus seems to be of particular interest since not only exotoxins, but also other proteins of S. aureus can induce specific humoral and cellular immune responses which partially also correlate with the severity of AD. In a subgroup of AD patients Malassezia species induce specific IgE- and T cell-responses which has been demonstrated by atopy patch tests. Moreover, Mala s 13 is characterized by high cross-reactivity to the human corresponding protein (thioredoxin). Induction of a potential autoallergy due to molecular mimicry seems therefore to be relevant for Malassezia-sensitized AD patients. In addition, sensitization mechanisms to autoallergens aside from cross-reactivity are under current investigation. Regarding inhalant allergens, research projects are in progress with the aim to elucidate allergen-specific immune response mechanisms in more depth. For grass-pollen allergens a flare-up of AD following controlled exposure has been observed while for house dust mite-allergens a polarization towards Th2 and Th2/Th17 T cell phenotypes can be observed. These and further findings might finally contribute to the development of specific and effective treatments for aeroallergen-sensitized AD patients.

Microbiological assay-trienzyme procedure for total folates in cereals and cereal foods: collaborative study.

In 1996, U.S. Food and Drug Administration regulations mandated the fortification of enriched cereal-grain products with folic acid, thereby emphasizing the need for validated methods for total folates in foods, particularly cereal products. The AOAC Official Methods (944.12, 960.46) currently used for the analysis of folate in foods for compliance purposes are microbiological methods. When the fortification regulations were finalized, no Official AOAC or Approved AACC methods for folate in cereal-grain products were in place. The AOAC Official Method (992.05) for folic acid in infant formula does not incorporate important improvements in the extraction procedure and was not considered suitable for the analysis of folates in foods in general. A microbiological assay protocol using a trienzyme extraction procedure was prepared and submitted for comments to 40 laboratories with recognized experience in folate analysis. On the basis of comments, the method was revised to have the conjugase (gamma-glutamyl-carboxy-peptidase) treatment follow a protease treatment, to include the use of cryoprotected inoculum, and to include the spectroscopic standardization of the standard and optional use of microtiter plates. Thirteen laboratories participated in a collaborative study of 10 required and 10 optional cereal-grain products, including flour, bread, cookies, baking mixes, and ready-to-eat breakfast cereals. The majority of the participating laboratories performed the assay by the standard test tube method; others used the microtiter plate modification for endpoint quantitation with equal success. For the required products, the relative standard deviation between laboratories (RSD(R)) ranged from 7.4 to 21.6% for 8 fortified (or enriched) products compared with expected (Horwitz equation-based) values of 11-20%. RSD(R) values were higher (22.7-52.9%) for 2 unfortified cereal-grain products. For the optional products, the RSD(R) ranged from 1.8 to 11.2% for 8 fortified products. RSD(R) values were higher (27.9-28.7%) for 2 unfortified cereal-grain products. Based on the results of the collaborative study, the microbiological assay with trienzyme extraction is recommended for adoption as Official First Action.

Callosal disconnection in multiple sclerosis.

A patient with MS demonstrated a striking callosal disconnection syndrome. MRI revealed callosal atrophy and extensive bilateral white matter changes. Of 15 comparison patients with clinically definite MS, only one had minimal callosal disconnection. Callosal disconnection in MS may be due to pathology of the corpus callosum as well as extensive white matter disease.

Leukoencephalopathy in normal and pathologic aging: 2. MRI of brain lucencies.

A pilot study was performed to test the ability of MR to evaluate the brain lucencies shown by CT in Alzheimer disease patients and in normal control subjects. Eight patients with presumed Alzheimer disease and 47 normal controls, 12 over the age of 45 years and 35 under age 45, were studied. Each group included subjects with and without CT evidence of leukoencephalopathy. Inversion recovery, saturation recovery, and spin-echo scans were obtained using a 0.3-T permanent magnet prototype unit. Results indicated that MR was more sensitive than CT to parenchymal disease. Seven of the eight patients with Alzheimer disease showed patches of increased signal intensity on SE scans; only three had lucencies on their CT studies. None of the normal subjects under the age of 45 showed periventricular patches of increased SE signal intensity. T2-weighted SE imaging was performed in nine of the 12 normal subjects over 45 years old. Eight of the nine demonstrated periventricular patches of increased SE signal intensity. Faint CT lucencies were present in only one of these. The configuration of the patches of increased signal intensity was similar for both the normal and Alzheimer groups, but the extent of white-matter involvement was greater in the Alzheimer group.

The prevalence of sexually stressful events among females in the general population.

Five hundred sixteen adult females were administered a questionnaire inquiring into the nature of sexually stressful events in their lives. There were 500 responses, and, of those, 298 (59.9%) had experienced an event of this type. A total of 416 different incidents were reported. They were categorized by the authors as either noninvasive (harassment, obscene calls, exposures, "peepers") or invasive (fondling, attempted rape, rape). The invasive incidents were most often initiated by a friend, acquaintance, or relative. The noninvasive events were almost always perpetrated by strangers. The subjects were asked to report the emotional impact of the events. All were reported to be stressful, with rape being the most stressful event. Regardless of whether formal therapy was sought, all victims reported lowered stress levels over time. There were 98 incidents reported when the subjects were 13 years of age or younger. There were 45 invasive events, including 9 rapes. All the rapes were committed by acquaintances or relatives. Only one victim of childhood rape received professional attention. Of the 41 women who were raped, nearly 75% were raped by acquaintances or relatives. This does not parallel existing emergency room data, suggesting that the group of patients who report to medical authorities may be a skewed sample of rape victims. Only four victims reported their rapes to either legal or medical authorities.

Safety of administration of procaine hydrochloride-hematoporphyrin (KH3) to beagle dogs.

Data were collected as to food consumption, body weight, coat condition, blood cells and chemical constituents, as well as physical and chemical characteristics of urine on 31 adult Beagle dogs (male and female) during a control period and later at monthly intervals during course of the study. After the control period, the dogs were divided into four groups and were given orally for 90 days either placebo, 0.5 gm. (one capsule), 1.5 gm., or 3 gm. of KH3 per day. At the end of the study, animals were necropsied and organs weighed. The coat appeared to be glossy and have luxurious growth. The other parameters studied showed no significant variations from control or normal ranges. Tissues revealed no gross or microscopic abnormalities which could be attributed to treatment. On the basis of this study, KH3 does not appear to have any deleterious effect on dogs at dose levels which are substantially higher than those recommended for animal or human usage.