Initiating allopurinol therapy: do we need to know the patient's human leucocyte antigen status?

AIMS: Allopurinol hypersensitivity (AH) can rarely be manifest as Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) that have high mortality rates. Less serious, but still significant, skin and systemic hypersensitivity reactions form part of the AH spectrum. One hundred per cent of Han Chinese with SJS/TEN due to allopurinol have been found to be at least heterozygous for HLA-B*5801, the carriage rate for this allele in the Han Chinese population being about 15%. The association has been found to be weaker in Caucasians whose HLA-B*5801 carriage rate is less than 6%. We examined the relationship between the different skin hypersensitivity reactions to allopurinol and the HLA-B locus in Australian patients. METHODS: We examined 23 patients referred with AH. RESULTS: Five of six Australian SJS/TEN patients were heterozygous for HLA-B*5801 and four were of South-East Asian origin. Five AH patients without SJS/TEN were all Caucasian and only one of these was positive for HLA-B*5801. Twelve patients with allopurinol-induced maculopapular exanthema were negative for HLA-B*5801, including one South-East Asian. CONCLUSIONS: Cases of AH manifesting as SJS/TENS in Australians are more likely to be in those of Asian heritage. The place of routine testing for HLA-B*5801 prior to commencing allopurinol therapy requires further investigation. However, Han Chinese origin patients commencing allopurinol might be informed of the test and may elect to have it performed as there are alternative hypouricaemic medicines, such as probenecid thereby reducing the risk of a catastrophic reaction to allopurinol.

Clinical standards for the dosing and management of TB drugs.

BACKGROUND: Optimal drug dosing is important to ensure adequate response to treatment, prevent development of drug resistance and reduce drug toxicity. The aim of these clinical standards is to provide guidance on 'best practice´ for dosing and management of TB drugs.METHODS: A panel of 57 global experts in the fields of microbiology, pharmacology and TB care were identified; 51 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all participants.RESULTS: Six clinical standards were defined: Standard 1, defining the most appropriate initial dose for TB treatment; Standard 2, identifying patients who may be at risk of sub-optimal drug exposure; Standard 3, identifying patients at risk of developing drug-related toxicity and how best to manage this risk; Standard 4, identifying patients who can benefit from therapeutic drug monitoring (TDM); Standard 5, highlighting education and counselling that should be provided to people initiating TB treatment; and Standard 6, providing essential education for healthcare professionals. In addition, consensus research priorities were identified.CONCLUSION: This is the first consensus-based Clinical Standards for the dosing and management of TB drugs to guide clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment to improve patient care.

Towards precision dosing of vancomycin in critically ill patients: an evaluation of the predictive performance of pharmacometric models in ICU patients.

OBJECTIVES: Vancomycin dose recommendations depend on population pharmacokinetic models. These models have not been adequately assessed in critically ill patients, who exhibit large pharmacokinetic variability. This study evaluated model predictive performance in intensive care unit (ICU) patients and identified factors influencing model performance. METHODS: Retrospective data from ICU adult patients administered vancomycin were used to evaluate model performance to predict serum concentrations a priori (no observed concentrations included) or with Bayesian forecasting (using concentration data). Predictive performance was determined using relative bias (rBias, bias) and relative root mean squared error (rRMSE, precision). Models were considered clinically acceptable if rBias was between ±20% and 95% confidence intervals included zero. Models were compared with rRMSE; no threshold was used. The influence of clinical factors on model performance was assessed with multiple linear regression. RESULTS: Data from 82 patients were used to evaluate 12 vancomycin models. The Goti model was the only clinically acceptable model with both a priori (rBias 3.4%) and Bayesian forecasting (rBias 1.5%) approaches. Bayesian forecasting was superior to a priori prediction, improving with the use of more recent concentrations. Four models were clinically acceptable with Bayesian forecasting. Renal replacement therapy status (p < 0.001) and sex (p = 0.007) significantly influenced the performance of the Goti model. CONCLUSIONS: The Goti, Llopis and Roberts models are clinically appropriate to inform vancomycin dosing in critically ill patients. Implementing the Goti model in dose prediction software could streamline dosing across both ICU and non-ICU patients, considering it is also the most accurate model in non-ICU patients.

Towards precision dosing of vancomycin: a systematic evaluation of pharmacometric models for Bayesian forecasting.

OBJECTIVES: Vancomycin is a vital treatment option for patients suffering from critical infections, and therapeutic drug monitoring is recommended. Bayesian forecasting is reported to improve trough concentration monitoring for dose adjustment. However, the predictive performance of pharmacokinetic models that are utilized for Bayesian forecasting has not been systematically evaluated. METHOD: Thirty-one published population pharmacokinetic models for vancomycin were encoded in NONMEM®7.4. Data from 292 hospitalized patients were used to evaluate the predictive performance (forecasting bias and precision, visual predictive checks) of the models to forecast vancomycin concentrations and area under the curve (AUC) by (a) a priori prediction, i.e., solely by patient characteristics, and (b) also including measured vancomycin concentrations from previous dosing occasions using Bayesian forecasting. RESULTS: A priori prediction varied substantially-relative bias (rBias): -122.7-67.96%, relative root mean squared error (rRMSE) 44.3-136.8%, respectively-and was best for models which included body weight and creatinine clearance as covariates. The model by Goti et al. displayed the best predictive performance with an rBias of -4.41% and an rRMSE of 44.3%, as well as the most accurate visual predictive checks and AUC predictions. Models with less accurate predictive performance provided distorted AUC predictions which may lead to inappropriate dosing decisions. CONCLUSION: There is a diverse landscape of population pharmacokinetic models for vancomycin with varied predictive performance in Bayesian forecasting. Our study revealed the Goti model as suitable for improving precision dosing in hospitalized patients. Therefore, it should be used to drive vancomycin dosing decisions, and studies to link this finding to clinical outcomes are warranted.

Phototactic migration of Dictyostelium cells is linked to a new type of gelsolin-related protein.

The molecular and functional characterization of a 125-kDa Ca2+-extractable protein of the Triton X-100-insoluble fraction of Dictyostelium cells identified a new type of a gelsolin-related molecule. In addition to its five gelsolin segments, this gelsolin-related protein of 125 kDa (GRP125) reveals a number of unique domains, two of which are predicted to form coiled-coil regions. Another distinct attribute of GRP125 concerns the lack of sequence elements known to be essential for characteristic activities of gelsolin-like proteins, i.e. the severing, capping, or nucleation of actin filaments. The subcellular distribution of GRP125 to vesicular compartments suggests an activity of GRP125 different from actin-binding, gelsolin-related proteins. GRP125 expression is tightly regulated and peaks at the transition to the multicellular pseudoplasmodial stage of Dictyostelium development. GRP125 was found indispensable for slug phototaxis, because slugs fail to correctly readjust their orientation in the absence of GRP125. Analysis of the GRP125-deficient mutant showed that GRP125 is required for coupling photodetection to the locomotory machinery of slugs. We propose that GRP125 is essential in the natural environment for the propagation of Dictyostelium spores. We also present evidence for further representatives of the GRP125 type in Dictyostelium, as well as in heterologous cells from lower to higher eukaryotes.

DdLIM is a cytoskeleton-associated protein involved in the protrusion of lamellipodia in Dictyostelium.

DdLim, a multi-domain member of the cysteine-rich family of LIM domain proteins, was isolated from Dictyostelium cells where it localizes in lamellipodia and at sites of membrane ruffling. The transcription and expression of DdLim are developmentally regulated, and the timing of its increased association with the actin cytoskeleton coincides with the acquisition in starved cells of a motile, chemotactic behavior. Vegetative cells that overexpress DdLim contain large lamella and exhibit ruffling at the cortex. The high frequency of large, multinucleated mutant cells found in suspension culture suggests that excess DdLim interferes with cytokinesis. DdLim was also identified as a protein in a Dictyostelium cell lysate that associated indirectly, but in a guanosine triphosphate-dependent manner, with a GST-rac1 fusion protein. The data presented suggest that DdLim acts as an adapter protein at the cytoskeleton-membrane interface where it is involved in a receptor-mediated rac1-signaling pathway that leads to actin polymerization in lamellipodia and ultimately cell motility.

Interaction of a Dictyostelium member of the plastin/fimbrin family with actin filaments and actin-myosin complexes.

A protein purified from cytoskeletal fractions of Dictyostelium discoideum proved to be a member of the fimbrin/plastin family of actin-bundling proteins. Like other family members, this Ca(2+)-inhibited 67-kDa protein contains two EF hands followed by two actin-binding sites of the alpha-actinin/beta-spectrin type. Dd plastin interacted selectively with actin isoforms: it bound to D. discoideum actin and to beta/gamma-actin from bovine spleen but not to alpha-actin from rabbit skeletal muscle. Immunofluorescence labeling of growth phase cells showed accumulation of Dd plastin in cortical structures associated with cell surface extensions. In the elongated, streaming cells of the early aggregation stage, Dd plastin was enriched in the front regions. To examine how the bundled actin filaments behave in myosin II-driven motility, complexes of F-actin and Dd plastin were bound to immobilized heavy meromyosin, and motility was started by photoactivating caged ATP. Actin filaments were immediately propelled out of bundles or even larger aggregates and moved on the myosin as separate filaments. This result shows that myosin can disperse an actin network when it acts as a motor and sheds light on the dynamics of protein-protein interactions in the cortex of a motile cell where myosin II and Dd plastin are simultaneously present.

DAPK2 regulates oxidative stress in cancer cells by preserving mitochondrial function.

Death-associated protein kinase (DAPK) 2 is a serine/threonine kinase that belongs to the DAPK family. Although it shows significant structural differences from DAPK1, the founding member of this protein family, DAPK2 is also thought to be a putative tumour suppressor. Like DAPK1, it has been implicated in programmed cell death, the regulation of autophagy and diverse developmental processes. In contrast to DAPK1, however, few mechanistic studies have been carried out on DAPK2 and the majority of these have made use of tagged DAPK2, which almost invariably leads to overexpression of the protein. As a consequence, physiological roles of this kinase are still poorly understood. Using two genetically distinct cancer cell lines as models, we have identified a new role for DAPK2 in the regulation of mitochondrial integrity. RNA interference-mediated depletion of DAPK2 leads to fundamental metabolic changes, including significantly decreased rate of oxidative phosphorylation in combination with overall destabilised mitochondrial membrane potential. This phenotype is further corroborated by an increase in the production of mitochondrial superoxide anions and increased oxidative stress. This then leads to the activation of classical stress-activated kinases such as ERK, JNK and p38, which is observed on DAPK2 genetic ablation. Interestingly, the generation of oxidative stress is further enhanced on overexpression of a kinase-dead DAPK2 mutant indicating that it is the kinase domain of DAPK2 that is important to maintain mitochondrial integrity and, by inference, for cellular metabolism.

Stress-induced tyrosine phosphorylation of actin in Dictyostelium cells and localization of the phosphorylation site to tyrosine-53 adjacent to the DNase I binding loop.

Actin is known to be phosphorylated at tyrosine, serine, or threonine residues in various cells. In cells of Dictyostelium discoideum, a rise in the tyrosine phosphorylation of actin is observed in response to ATP depletion. An actin fraction rich in phosphotyrosine was obtained by chromatography on the weak anion exchanger Mono-P. Mass spectrometry and amino acid sequencing of protease cleavage products indicated that a single tyrosine residue was phosphorylated. Localization of this residue to position 53 of the actin sequence attributed the modification to a site that is critical for the capability of actin to polymerize. Induction of the tyrosine phosphorylation by heat shock and Cd2+ ions indicates that this modification of actin is implicated in the response of Dictyostelium cells to stress.

Host-donor interactions in healing of human split-thickness skin grafts onto nude mice: in situ hybridization, immunohistochemical, and histochemical studies.

The behavior of host and donor cell lines in human split-thickness skin grafts onto nude mice was studied by in situ hybridization (ISH) using genomic DNAs as probes, and immunohistochemically with species-specific or cross-species specific antibodies, at different stages ranging from day 3 to more than 1 year following grafting. Changes in the graft vascular and interstitial extracellular matrix were also assessed using species-specific or cross-species specific antibodies to human or murine type I, III, and IV collagens. Finally, transplant reinnervation was investigated using antibodies to various nerve cytoplasmic antigens and the thiocholine method to demonstrate acetylcholinesterase. Using these methods we were able to show the following: (1) the graft epidermis that is not replaced by mouse keratinocytes is progressively colonized by recipient Langerhans cells (LCs); (2) revascularization of the grafts begins soon by inoculation of the graft vessels with the host microcirculatory bed, and mouse endothelial cells growing into preexisting human capillary tubes produce a new basement membrane, prior to the replacement of the original one; (3) within 3-5 days following grafting, mouse fibroblasts migrate into the graft dermis. The density of the human and murine fibroblast populations then progressively increases. Characterization of the interstitial collagens identifies both human and murine type I and III collagens. Production of type III collagens decreases during the progression of fibrogenesis while human type I collagen becomes the predominant matrix protein; (4) transplant reinnervation is deficient, and neurites growing into severed graft nerve trunks were never detected.

Transneuronal tracing of neural pathways controlling activity of diaphragm motoneurons in the ferret.

Previous studies have shown that neurons in addition to those in the medullary respiratory groups are involved in activating phrenic motoneurons during a number of behaviors, including vomiting and reaction to vestibular stimulation. However, the location of premotor inspiratory neurons outside of the main medullary respiratory groups is largely unknown, particularly in emetic species. In the present study, the transneuronal tracer pseudorabies virus was injected into the diaphragm of the ferret, and the locations of retrogradely-labeled motoneurons and transneuronally-labeled pre-motoneurons in the brainstem and cervical and thoracic spinal cord were mapped. Injections of a monosynaptic tracer, cholera toxin, were also made in order to verify the location of motoneurons innervating the diaphragm. Phrenic motoneurons identified with pseudorabies virus and cholera toxin were confined largely to the C5-C7 levels of spinal cord, and often gave rise to prominent polarized dendritic arbors that extended across the midline. At post-inoculation survival times > or = three days, transneuronally-labeled interneurons were located in the cervical and thoracic spinal cord and portions of the brainstem, including the midline pontomedullary reticular formation and the lateral medullary reticular formation. Double-labeling studies revealed that although the infected midline neurons were located in the proximity of serotonergic neurons, only a small number of the virus-containing cells were positive for serotonin. These findings suggest that neurons in the midline of the medulla and pons influence the activity of phrenic motoneurons, perhaps during inspiratory behaviors unique to emetic animals (such as vomiting).

EWS and WT-1 gene fusion in desmoplastic small round cell tumor of the abdomen.

Chromosome translocations found in neoplasms often result in the creation of hybrid genes encoding chimeric proteins. This case study describes a patient with desmoplastic small round cell tumor (DSRCT) of the abdomen, an aggressive neoplasm characterized by translocation of chromosomes 11 and 22. Southern hybridization showed that the Ewing sarcoma gene (EWS) gene was rearranged in the DSRCT. Reverse transcriptase-polymerase chain reaction analysis of tumor cell RNA revealed that exons 1 to 7 of the EWS gene were joined to exons 8 to 10 of the Wilms' Tumor-1 (WT-1) gene resulting in the production of a chimeric message. The WT-1 and EWS genes encode DNA and RNA binding proteins involved in Wilms' tumor and Ewing sarcoma pathogenesis, respectively. The fusion of these two genes in DSRCT results in the production of a putatively oncogenic protein composed of the zinc finger DNA binding domains of WT-1 linked to potential transcriptional regulatory domains of EWS. DNA sequencing revealed the genomic breakpoints of translocation on chromosomes 11 and 22. The genomic breakpoint on chromosome 22 occurred in EWS intron 7 just 2 nucleotides 3' of exon 7. Polymerase chain reaction-based assays were developed that could detect the fused genes in the DSRCT tumor using either RNA or genomic DNA. The potential diagnostic use of these assays is discussed.

Excitatory inputs to the RVLM in the context of the baroreceptor reflex.

The central neural circuit mediating baroreceptor control of sympathetic vasomotor outflow involves an excitatory projection from arterial baroreceptors to nucleus tractus solitarius, an excitatory projection from nucleus tractus solitarius to the caudal ventrolateral medulla, an inhibitory projection from the caudal ventrolateral medulla to the rostral ventrolateral medulla (RVLM), and an excitatory projection from the RVLM to sympathetic preganglionic neurons in the spinal cord. For this circuit to be operational, the relevant neurons in the RVLM must be tonically active. Indeed, numerous studies have demonstrated that RVLM vasomotor neurons are tonically active; however, little is known regarding the nature of the tonic excitatory drive to these neurons. We present a model in which RVLM vasomotor neurons are tonically excited by inputs to the RVLM that can be blocked by the excitatory amino acid receptor antagonist, kynurenic acid, as well as an input from the caudal ventrolateral medulla that is not sensitive to kynurenic acid.

Exogenous testosterone differentially affects myelination and neurone soma sizes in the brain of canaries.

We assessed the temporal and functional relationship of myelin maturation and of neuronal development in the telencephalic song motor centres of the canary at different developmental stages. Brain differentiation was modulated by exogenous testosterone, its effects on song quality were also monitored. Myelin maturation was studied by using computer aided analysis of silver impregnated brain sections, whereas the differentiation of neurones was determined by measuring neuronal soma sizes. At an early developmental stage, testosterone triggers growth of neurones but does not affect myelination. At a later developmental stage, both neurone soma sizes and myelination are enhanced by testosterone.

Antioestrogen inhibits myelination in brains of juvenile Zebra finches.

The effects of the antioestrogen Keoxifene on the ontogenetic process of myelination, on the differentiation of neurones of telencephalic song motor centres, on cerebellar structures and on behaviour were studied in male Zebra finches. Brain differentiation was studied by using computer aided analysis of silver impregnated brain sections and by measuring soma sizes of neurones after Nissl staining. An antioestrogen induced inhibition of myelination could be detected in the song motor centre robust nucleus of the archistriatum (RA) and in the cerebellum, whereas the region magnocellular nucleus of the anterior neostriatum (MAN) showed no difference between treated birds and controls.

Specific interaction of food proteins with apical membranes of the human intestinal cell lines Caco-2 and T84.

A comparison between the intestinal epithelial cell lines Caco-2 and T84 was made to assess the influence of enterocytic differentiation on food protein binding capacities of the brush border membrane. Cell morphology and expression of brush border-associated enzymes were studied as differentiation markers. Food protein binding to isolated brush border membranes was measured with a dot blot chemiluminescence assay. Early at confluence, Caco-2 cells exhibited a more differentiated state compared to T84 cells. Brush border membranes of both cell lines bound gliadin peptides, beta-lactoglobulin and ovalbumin specifically. Binding capacities increased from gliadin peptides to ovalbumin to beta-lactoglobulin. There was correlation of membrane binding capacity with degree of cell differentiation. Due to their similarity to small intestinal epithelial cells, the colon carcinoma cell lines Caco-2 and T84 represent models for studying food protein-enterocytic brush border membrane interactions in relation to varying degrees of cell differentiation.

Intraoperative detection of malignant gliomas by 5-aminolevulinic acid-induced porphyrin fluorescence.

OBJECTIVE: Survival after surgery and radiotherapy for the treatment of malignant gliomas is linked to the completeness of tumor removal. Therefore, methods that permit intraoperative identification of residual tumor tissue may be of benefit. In a preliminary investigation, we have studied the value of fluorescent porphyrins that accumulate in malignant tissue after administration of a precursor (5-aminolevulinic acid) for labeling of malignant gliomas in nine patients. METHODS: Three hours before the induction of anesthesia, 10 mg 5-aminolevulinic acid/kg body weight was administered orally. Intraoperatively, red porphyrin fluorescence was observed with a 455-nm long-pass filter after excitation with violet-blue (375-440 nm) xenon light and was verified by analysis of fluorescence spectra. Fluorescing and nonfluorescing samples taken from the tumor perimeters were examined histologically or used to study the photobleaching of porphyrins by excitation light and white light from the operating microscope. Plasma and erythrocyte porphyrin levels were determined by fluorescence photometry. RESULTS: Normal brain tissue revealed no porphyrin fluorescence, whereas tumor tissue was distinguished by bright red fluorescence. For a total of 89 tissue biopsies, sensitivity was 85% and specificity was 100% for the detection of malignant tissue. For seven of nine patients, visible porphyrin fluorescence led to further resection of the tumor. Under operating light conditions, fluorescence decayed to 36% in 25 minutes for violet-blue light and in 87 minutes for white light. Plasma and erythrocyte porphyrin contents increased slightly, without exceeding normal levels. CONCLUSION: Our observations suggest that 5-aminolevulinic acid-induced porphyrin fluorescence may label malignant gliomas safely and accurately enough to enhance the completeness of tumor removal.

In vivo fluorescence kinetics of porphyrins following intravesical instillation of 5-aminolaevulinic acid in normal and tumour-bearing rat bladders.

The fluorescence kinetics of protoporphyrin IX (PPIX) following intravesical instillation of 5-aminolaevulinic acid (5-ALA) have been studied in vivo in a rat bladder tumour model. 5-ALA dissolved in NaHCO3 was intravesically instilled for 60 min in tumour-bearing and normal bladders of Wistar rats. The fluorescence was excited with the violet lines of a Kr(+)-laser and recorded in vivo by means of a fibre coupled optical multichannel analyser. The fluorescence emission bands of PPIX at lambda = 636 nm and lambda = 708 nm were detected in normal and tumorous urothelium after only 30 min. The maximum fluorescence intensity was obtained in tumorous and normal urothelium 3-4 h after instillation. The ratio of the fluorescence intensity in tumorous to normal urothelium decreased continuously from four to about two during the time range of 6 h. PPIX fluorescence following 5-ALA instillation could also be observed in kidney and liver. Fluorescence from further porphyrin species with emission bands at lambda = 617 nm and lambda = 682 nm was detected in the bladder, indicating an efflux of hydrophilic porphyrins from the hepatic pathway.

Pharmacokinetics of 5-aminolevulinic-acid-induced porphyrins in tumour-bearing mice.

Photodynamic therapy and photodynamic diagnosis help to support efficient treatment of superficial and early-stage cancer. During the last few years, 5-aminolevulinic acid (5-ALA), a precursor of haemoglobin in the haem biosynthetic pathway, was used to stimulate endogenous porphyrin production. In the following the time dependence of 5-ALA-induced porphyrin concentration will be investigated on several tissues in an in-vivo tumour model. 5-ALA was administered intravenously at a concentration of 50 mg-1 body weight. According to a certain time schedule the animals were sacrificed and 12 different organs as well as the tumour were removed. During excitation with the violet light of a Kr+ laser, porphyrin fluorescence spectra in the range 550-750 nm could be detected on the tissue samples. The intensity of the emission spectra at lambda = 635 +/- 2 nm was taken as a measure of the porphyrin concentration. All tissues showed porphyrin fluorescence. Brightest fluorescence was found on the tumour. A maximum contrast of the fluorescence intensity between the tumour and the non-malignant organs of up to 30 was observed at 4-6 h post-injection. The kinetics of the porphyrin concentration depend on the organ. Simple mathematical models will be derived and discussed.

In vitro and in vivo porphyrin accumulation by C6 glioma cells after exposure to 5-aminolevulinic acid.

Several malignant tissues synthesize endogenous porphyrins after exposure to 5-aminolevulinic acid (5-ALA). The present experiments have been designed to elucidate whether the C6 glioma cell, a model cell for human malignant glioma, similarly synthesizes porphyrins when exposed to 5-ALA, and whether specific synthesis occurs when C6 cells are inoculated into rat brains to form a tumor. In this situation the blood-brain barrier may interfere with 5-ALA availability, and spreading of porphyrins with edema outside the tumor may occur. Flow cytometry is used to determine the course of cell volume and porphyrin fluorescence intensities in cultured C6 cells which are incubated in 1 mM 5-ALA. For the induction of experimental brain tumors, 10(4) untreated C6 cells are inoculated into the brains of rats. After 9 days animals receive 100 mg 5-ALA/kg body weight. Brains are removed after 3, 6, or 9 h and frozen coronal sections obtained for H/E staining or fluorescence spectography. Cultured C6 cells show a linear increase of protoporphyrin IX fluorescence after exposure to 5-ALA, which begins to plateau after 85 min. Marked fluorescence is also observed in solid and infiltrating experimental tumor. However, faint fluorescence also occurs in normal tissue, basal pia, choroid plexus, and, more obviously, in white-matter tracts bordering the tumor (maximal distance: 1.5 +/- 0.7 mm). The observations demonstrate that C6 cells synthesize protoporphyrin IX after exposure to 5-ALA in vitro and in vivo. However, when utilizing 5-ALA for fluorescence detection or photodynamic therapy of brain tumors, attention should be paid to the possibility of protoporphyrin IX occurring outside the tumor.