Comparison of the uptake of 5-aminolevulinic acid and its methyl ester in keratinocytes and skin.

Photodynamic therapy is widely used in the treatment of superficial skin cancers. 5-Aminolevulinic acid (ALA) and its methylated form, methyl-ALA (MAL), are frequently used as precursors to photosensitizing substances. Nevertheless, the mechanism of the uptake of ALA and MAL in keratinocytes and of their skin penetration is still controversial. Since both compounds are not sufficiently lipophilic to penetrate through lipid membranes, they must employ specific uptake systems which may vary between different cell types. Here, we studied ALA and MAL uptake in keratinocyte cell lines originating from healthy cells (CCD 1106 KERTr cells) or keratinocyte tumors (A431 cells). ALA uptake resulted in faster protoporphyrin IX (PpIX) production than MAL uptake. A pharmacological characterization of the uptake systems revealed that PpIX formation was most efficiently reduced with GABA transporter (GAT) substrates. GABA, ß-alanine, and (S)-SNAP-5114 reduced ALA uptake and, to a lesser extent, MAL uptake in the cell lines. The pharmacology of these compounds indicates that ALA and MAL are taken up by normal and pathological keratinocytes via GAT-3. Furthermore, the amino acids arginine, cysteine, and histidine also inhibited the uptake of ALA, and even more so MAL, suggestive of an additional involvement of amino acid transporters. To show that PpIX formation in vivo is restricted to the application site, which has been questioned for ALA in one other report, we applied clinically used ALA and MAL formulations to the skin of nude mice. Contrary to the results of these previous authors, the resulting PpIX fluorescence increased over time and was restricted to the application site for both preparations.

δ-Aminolevulinic acid and its methyl ester induce the formation of Protoporphyrin IX in cultured sensory neurones.

Application of δ-aminolevulinic acid (ALA) or its methyl ester (MAL) onto cutaneous tumours increases intracellular Protoporphyrin IX (PpIX), serving as photosensitizer in photodynamic therapy (PDT). While PDT is highly effective as treatment of neoplastic skin lesions, it may induce severe pain in some patients. Here, we investigated ALA and MAL uptake and PpIX formation in sensory neurones as potential contributor to the pain. PpIX formation was induced in cultured sensory neurones from rat dorsal root ganglion by incubation with ALA or MAL. Using inhibitors of GABA transporters (GAT), a pharmacological profile of ALA and MAL uptake was assessed. GAT mRNA expression in the cultures was determined by RT-PCR. Cultured sensory neurones synthesised Protoporphyrin IX (PpIX) from extracellularly administered ALA and MAL. PpIX formation was dose- and time-dependent with considerably different kinetics for both compounds. While partial inhibition occurred using L-arginine, PpIX formation from both ALA and MAL could be fully blocked by the GABA-Transporter (GAT)-2/3 inhibitor (S)-SNAP 5114 with similar K (i) (ALA: 195 ± 6 µM; MAL: 129 ± 13 µM). GAT-1 and GAT-3 could be detected in sensory neurons using RT-PCR on mRNA level and using [³H]-GABA uptake on protein level. Cultured sensory neurones take up ALA and MAL and synthesize PpIX from both, enabling a direct impact of photodynamic therapy on cutaneous free nerve endings. The pharmacological profile of ALA and MAL uptake in our test system was very similar and suggests uptake via GABA and amino acid transporters.

Hospital-acquired candida and aspergillus pneumonia--diagnostic approaches and clinical findings.

Bronchoscopy with bronchoalveolar lavage (BAL), collection of bronchial secretions (BS) and/or high resolution computed tomography (CT) of the lungs was performed in 70 patients with candida and/or aspergillus pneumonia. The sensitivity of bronchoscopy in detecting histologically proven fungal disease was 59%. Characteristic CT signs were found in 11 of 14 patients with candida pneumonia and 16 of 19 patients with aspergillosis. The more frequent use of bronchoscopy and CT scans between 1990 and 1992 compared with 1986-1989 for the differential diagnosis of new pulmonary infiltrates in immunocompromised patients resulted in earlier antifungal treatment (14 vs. nine days; P < 0 center dot 025). In the second treatment period survival was improved from 36 to 50% (not significant). Bronchoscopy and high resolution CT scans are mutually complementary diagnostic tools and should be performed as early as possible in the course of pneumonia in patients at high risk of fungal diseases.

Pulmonary fungal infections in patients with hematological malignancies--diagnostic approaches.

In a retrospective study of 56 patients with hematological malignancies and fungal pneumonia we have analyzed the value of different diagnostic procedures. In all patients (Candida n = 29, Aspergillus n = 23, mixed fungal infection n = 4) bronchoscopy and/or high-resolution computed tomography of the lungs was performed. Cultural detection of fungi in bronchoalveolar lavage was successful in 23/32 Candida and 11/23 Aspergillus pneumonias. Other relevant pathogens were identified by bronchoscopy in 21 cases. Thorax CT scans showed diagnostic evidence of fungal pneumonia in 10/13 Candida and in 16/18 Aspergillus infections. Blood cultures were positive in 9/33 Candida pneumonias and in none of aspergillosis cases. Serological testing and surveillance cultures had only limited value for the early diagnosis of pulmonary mycosis. Our data suggest that bronchoscopy and high resolution CT scans are mutually complementary diagnostic tools with high sensitivity in patients with hematological malignancies and new pulmonary infiltrates. These procedures facilitate the early and reliable recognition of invasive fungal disease which may have a bearing on the initiation, length, and differential therapy of antimycotic drugs.

Pulmonary aspergillosis: early diagnosis improves survival.

Bronchoscopy obtaining bronchoalveolar lavage (BAL) fluid and bronchial secretions (BS) and/or high-resolution computed tomography (CT) of the lungs were performed in 33 patients with pulmonary aspergillosis from 1987 to 1992. The sensitivity of BAL fluid or BS for detecting histologically proven fungal disease was 33 and 50%, respectively, whereas positive serologies were only documented in 8% of the cases. CT scans contributed to the early diagnosis of opportunistic fungal pneumonia: characteristic CT signs were found in 16 of 19 episodes. The more frequent use of bronchoscopy and CT scans between 1990 and 1992 compared to 1987-1989 for the differential diagnosis of new pulmonary infiltrates resulted in earlier appropriate treatment. The average introduction of intravenous (i.v.) antifungal therapy after the onset of pneumonia was shifted from 12 to 7 days (p < 0.05). The timely implementation of i.v. antimycotic therapy had a significant impact on survival. Initiation of antifungal treatment later than 10 days after the onset of pneumonia resulted in a mortality of 90%, as opposed to 41% with an earlier start of antimycotics (p < 0.01). The earlier use of appropriate antifungal therapy in the second treatment period improved survival from 33 to 50% (NS). Bronchoscopy and high-resolution CT scans are mutually complementary diagnostic tools and should be performed as early as possible in the course of pneumonia for patients at high risk for aspergillosis.

Neutrophils and the mechanism of IUD action in rats.

Current research on the mechanism of action of the IUD has focused on a local, low-grade endometritis in preventing blastocystic implantation. With rabbit antisera to rat neutrophils, a neutropenic state was induced in rats having a silk suture in one uterine horn. Assay for nidation sites in the severely polymorphdepleted rats revealed no implantation sites in the IUD horn and an average of 5.8 sites in the control horn, suggesting that inflammation plays a relatively minor role, if any, in the mechanism of action of the IUD.