Fluorescence remission spectroscopy of psoriatic lesions and the effect of topical anthralin therapy

BACKGROUND

Psoriatic lesions are characterized by induration, scaling and erythema. Erythema is a result of inflammation and increased microvascular blood flow. Anthralin is the strongest topical antipsoriatic drug that causes clearing of psoriatic lesions and temporary remission.

OBJECTIVE

The objective evaluation of skin perfusion might be a suitable way to gain a better insight in the pathophysiological process of this disease and to evaluate the response to antipsoriatic anthralin therapy.

METHODS

We evaluated 21 psoriatic lesions (plaques, patches and pinpoint lesions) including 4 lesions in remission with anthralin induced erythema and 4 controls of healthy, uninvolved skin. We performed the measurements with a combined fluorescence and remission imaging (FRIS). The FRIS sensor is coupled with a touch screen industrial computer. The equipment consists of a white-light halogen lamp (20 W), two VIS-spectrometer modules (Zeiss) for remission detection and references. Imaging is realized by CCD-colour camera module and white light ring-lighting. Fluorescence emission was realized using an ultraviolet LED with a wavelength of 370 nm. The fluorescence detector is a highly sensitive MCS CCD (Zeiss) with an integration time of 2.5 sec.

RESULTS

Spectral remission of psoriatic skin is characterized by a pronounced decrease (60-80%) of the haemoglobin double-peak compared to uninvolved skin. The NADH-fluorescence is diminished in lesional psoriatic skin including anthralin-treated areas with clinical remission.

CONCLUSIONS

Vascular perfusion is increased in psoriatic lesions as demonstrated by remission spectroscopy. NADH-fluorescence is reduced in lesional psoriatic skin and in anthralin-induced erythema. FRIS is a suitable tool for objective evaluation of the cutaneous response to antipsoriatic treatment.

The synthetic peptide PFWT disrupts AF4–AF9 protein complexes and induces apoptosis in t(4;11) leukemia cells

The MLL gene at chromosome band 11q23 is commonly involved in reciprocal translocations detected in acute leukemias. A number of experiments show that the resulting MLL fusion genes directly contribute to leukemogenesis. Among the many known MLL fusion partners, AF4 is relatively common, particularly in acute lymphoblastic leukemia in infants. The AF4 protein interacts with the product of another gene, AF9, which is also fused to MLL in acute leukemias. Based on mapping studies of the AF9-binding domain of AF4, we have developed a peptide, designated PFWT, which disrupts the AF4-AF9 interaction in vitro and in vivo. We provide evidence that this peptide is able to inhibit the proliferation of leukemia cells with t(4;11) chromosomal translocations expressing MLL-AF4 fusion genes. Further, we show that this inhibition is mediated through apoptosis. Importantly, the peptide does not affect the proliferative capacity of hematopoietic progenitor cells. Our findings indicate that the AF4-AF9 protein complex is a promising new target for leukemia therapy and that the PFWT peptide may serve as a lead compound for drug development.

MLL fusion partners AF4 and AF9 interact at subnuclear foci

The MLL gene is involved in translocations associated with both acute lymphoblastic and acute myelogenous leukemia. These translocations fuse MLL with one of over 30 partner genes. Collectively, the MLL partner genes do not share a common structural motif or biochemical function. We have identified a protein interaction between the two most common MLL fusion partners AF4 and AF9. This interaction is restricted to discrete nuclear foci we have named 'AF4 bodies'. The AF4 body is non-nucleolar and is not coincident with any known nuclear structures we have examined. The AF4-AF9 interaction is maintained by the MLL-AF4 fusion protein, and expression of the MLL-AF4 fusion can alter the subnuclear localization of AF9. In view of other research indicating that other MLL fusion partners also interact with one another, these results suggest that MLL fusion partners may participate in a web of protein interactions with a common functional goal. The disruption of this web of interactions by fusion with MLL may be important to leukemogenesis.

Cloning and developmental expression of the murine homolog of the acute leukemia proto-oncogene AF4

AF4 is the 4q21 gene involved in the acute lymphoblastic leukemia associated t(4;11)(q21;q23) where it forms a fusion gene with MLL. In order to gain insight into AF4's role in leukemogenesis we have studied its functional domains and expression pattern during murine development. We have cloned the murine homolog, Af4. We have demonstrated that 5' half of Af4 encodes a region with transcriptional transactivation activity which is disrupted by the t(4;11) in human leukemias. We have also localized the murine AF4 protein to the nucleus supporting a role for AF4 in transcription. The developmental expression pattern of Af4 was determined in situ hybridization and suggests Af4 plays an important role in the development of the hematopoietic, cardiovascular, skeletal and central nervous systems. A repeating pattern of Af4 expression in development is down-regulation with differentiation of a tissue. Among the cell types where this pattern of down-regulation is noted are B-lymphocytes. These findings raise the possibility that the disruption of normal AF4 function by the translocation may contribute to leukemogenesis.

Reduced cyclin D1 expression in the cerebella of nutritionally deprived rats correlates with developmental delay and decreased cellular DNA synthesis

Nutritional deprivation in the early postnatal period severely inhibits cerebellar growth and development, which is related in part to reduced levels of growth factors. Cyclin D1 encodes a growth factor-inducible regulatory subunit of a serine/thereonine kinase that is capable of phosphorylating the tumor suppressor pRB, thereby allowing normal progression through the G1 phase of the cell-cycle. Because the abundance of cyclin D1 is rate limiting in this progression, we examined the regulation of cyclin D1 expression in vivo, using a model of nutritional deprivation. Cyclin D1 expression in cerebella of fed control rats was detected in the external granular layer and was associated with cellular proliferation within this layer. Nutritional deprivation of rats reduced cerebellar weight, as well as the thickness of the molecular layer that largely consists of cells migrating from the external granular layer. Refeeding partially restored cerebellar weight, molecular layer thickness and increased external granular layer cyclin D1 immunostaining. Since nutritional deprivation is accompanied by lower levels of circulating insulin-like growth factor-I (IGF-I), we determined whether IGF-I directly stimulated the cyclin D1 promoter. The human cyclin D1 promoter linked to the luciferase reporter gene was stably integrated into PC12 cells. IGF-I stimulated cyclin D1 promoter activity 4- to 6-fold at 6 hours (h). These findings are consistent with the notion that nutritional deprivation may affect proliferative growth by altering expression of cyclin D1 in the germinal cell layer and that regulation of cyclin D1 expression by growth factors may contribute to normal neonatal cerebellar development. The reduction in cyclin D1 expression as cells differentiate in the cerebellum is consistent with a potential role for cyclin D1 in this process.

Amphibian allantoinase. Molecular cloning, tissue distribution, and functional expression

The chain of enzymes necessary to convert uric acid to its metabolic products urea and glyoxylic acid in vertebrates is truncated through the successive loss of allantoicase, allantoinase, and urate oxidase during phylogenetic evolution. Previous studies have assigned the localization of both urate oxidase and allantinase to the peroxisome in the amphibian liver. This study reports the cloning of a cDNA encoding bullfrog (Rana catesbeiana) allantoinase, an enzyme that converts allantoin to allantoic acid. The cDNA is 2112 base pairs in length containing a 1449-base pair open reading frame which corresponds to a 483-residue protein (53,296 Da). Structural analysis of the deduced protein suggested two potential transmembrane segments and the presence of a putative mitochondrial localization sequence in the amino terminus. Immunocytochemical analysis revealed that allantoinase is localized to mitochondria and not to peroxisomes. On Northern blotting, a single mRNA species was detected in the liver and kidney of frog but not in other tissues; this distribution was confirmed by immunoblotting. The hepatic- and renal-specific expression of allantoinase coincides with the distribution of urate oxidase in these tissues in the frog. The allantoinase expressed in Saccharomyces cerevisiae and in Spodoptera frugiperda (Sf9) insect cells exhibits catalytic activity and is antigenically identical to the native frog enzyme.

Greig syndrome in a large kindred due to reciprocal chromosome translocation t(6;7)(q27;p13)

We report on cases of Greig syndrome segregating in a large kindred over four generations due to reciprocal translocation t(6;7)(q27;p13) and on a patient from this pedigree with a severe malformation syndrome due to duplication 7(p13----pter). The clinical findings are discussed as possible consequence of a gene mutation due to the break at 7p13.

[Clinical relevance of the so-called arteria lusoria in childhood]

Although arteria lusoria is relatively frequent, symptomatic cases are rare in childhood. Symptoms are not caused by the retroesophageal course of the vessel itself, but by additional anomalies of the other branches of the aortic arch, above all by the pretracheal course of the equilateral arteria carotis communis. In very rare cases, the anomalous right arteria subclavia passes between esophagus and trachea and may cause threatened impending respiratory disturbances together with an aberrant course of the arteria carotis. The diagnostic and therapeutic procedure is discussed; the development of pulmonary hypertension in vascular respiratory disturbances is pointed out.