5-Aminolevulinic acid bypasses mitochondrial complex I deficiency and corrects physiological dysfunctions in Drosophila.

Complex I (CI) deficiency in mitochondrial oxidative phosphorylation (OXPHOS) is the most common cause of mitochondrial diseases, and limited evidence-based treatment options exist. Although CI provides the most electrons to OXPHOS, complex II (CII) is another entry point of electrons. Enhancement of this pathway may compensate for a loss of CI; however, the effects of boosting CII activity on CI deficiency are unclear at the animal level. 5-Aminolevulinic acid (5-ALA) is a crucial precursor of heme, which is essential for CII, complex III, complex IV (CIV) and cytochrome c activities. Here, we show that feeding a combination of 5-ALA hydrochloride and sodium ferrous citrate (5-ALA-HCl + SFC) increases ATP production and suppresses defective phenotypes in Drosophila with CI deficiency. Knockdown of sicily, a Drosophila homolog of the critical CI assembly protein NDUFAF6, caused CI deficiency, accumulation of lactate and pyruvate and detrimental phenotypes such as abnormal neuromuscular junction development, locomotor dysfunctions and premature death. 5-ALA-HCl + SFC feeding increased ATP levels without recovery of CI activity. The activities of CII and CIV were upregulated, and accumulation of lactate and pyruvate was suppressed. 5-ALA-HCl + SFC feeding improved neuromuscular junction development and locomotor functions in sicily-knockdown flies. These results suggest that 5-ALA-HCl + SFC shifts metabolic programs to cope with CI deficiency. Bullet outline 5-Aminolevulinic acid (5-ALA-HCl + SFC) increases ATP production in flies with complex I deficiency.5-ALA-HCl + SFC increases the activities of complexes II and IV.5-ALA-HCl + SFC corrects metabolic abnormalities and suppresses the detrimental phenotypes caused by complex I deficiency.

Polymeric iron chelators for enhancing 5-aminolevulinic acid-induced photodynamic therapy.

5-Aminolevulinic acid (5-ALA) is an amino acid that can be metabolized into a photosensitizer, protoporphyrin IX (PpIX) selectively in a tumor cell, permitting minimally invasive photodynamic diagnosis/therapy. However, some malignant tumor cells have excess intracellular labile iron and facilitate the conversion of PpIX into heme, which compromises the therapeutic potency of 5-ALA. Here, we examined the potential of chelation of such unfavorable intratumoral labile iron in photodynamic therapy (PDT) with 5-ALA hydrochloride, using polymeric iron chelators that we recently developed. The polymeric iron chelator efficiently inactivated the intracellular labile iron in cultured cancer cells and importantly enhanced the accumulation of PpIX, thereby improving the cytotoxicity upon photoirradiation. Even in in vivo study with subcutaneous tumor models, the polymeric iron chelator augmented the intratumoral accumulation of PpIX and the PDT effect. This study suggests that our polymeric iron chelator could be a tool for boosting the effect of 5-ALA-induced PDT by modulating tumor microenvironment.

5-Aminolevulinic acid/sodium ferrous citrate enhanced the antitumor effects of programmed cell death-ligand 1 blockade by regulation of exhausted T cell metabolism in a melanoma model.

Mitochondria are key cytoplasmic organelles. Their activation is critical for the generation of T cell proliferation and cytotoxicity. Exhausted tumor-infiltrating T cells show a decreased mitochondrial function and mass. 5-Aminolevulinic acid (5-ALA), a natural amino acid that is only produced in the mitochondria, has been shown to influence metabolic functions. We hypothesized that 5-ALA with sodium ferrous citrate (SFC) might provide metabolic support for tumor-infiltrating T cells. In a mouse melanoma model, we found that 5-ALA/SFC with a programmed cell death-ligand 1 (PD-L1) blocking Ab synergized tumor regression. After treatment with 5-ALA/SFC and anti-PD-L1 Ab, tumor infiltrating lymphocytes (TILs) were not only competent for the production of cytolytic particles and cytokines (granzyme B, interleukin-2, and γ-interferon) but also showed enhanced Ki-67 activity (a proliferation marker). The number of activated T cells (PD-1+ Tim-3- ) was also significantly increased. Furthermore, we found that 5-ALA/SFC activated the mitochondrial functions, including the oxygen consumption rate, ATP level, and complex V expression. The mRNA levels of Nrf-2, HO-1, Sirt-1, and PGC-1α and the protein levels of Sirt-1 were upregulated by treatment with 5-ALA/SFC. Taken together, our findings revealed that 5-ALA/SFC could be a key metabolic regulator in exhausted T cell metabolism and suggested that 5-ALA/SFC might synergize with anti-PD-1/PD-L1 therapy to boost the intratumoral efficacy of tumor-specific T cells. Our study not only revealed a new aspect of immune metabolism, but also paved the way to develop a strategy for combined anti-PD-1/PD-L1 cancer immunotherapy.

Time to extinction of a cultural trait in an overlapping generation model.

How long a newly emerging trait will stay in a population is a fundamental but rarely asked question in cultural evolution. To tackle this question, the distribution and mean of the time to extinction of a discrete cultural trait are derived for models with overlapping generations, in which trait transmission occurs from multiple role models to a single newborn and may fail with a certain probability. We explore two models. The first is a Moran-type model, which allows us to derive the exact analytical formula for the mean time to extinction of a trait in a finite population. The second is a branching process, which assumes an infinitely large population and allows us to derive approximate analytical formulae for the distribution and mean of the time to extinction in the first model under a large population size. We show that in the first model, the mean time to extinction apparently diverges (becomes so large that even numerical computation is impractical) under a certain parameter condition as the population size tends to infinity. Using the second model, we explain the underlying mechanism of the apparent divergence found in the first model and derive the mathematical condition for this divergence in terms of transmission efficiency and the number of role models per newborn. When this mathematical condition is satisfied in the second model, the probability of extinction is less than 1, and the mean extinction time does not exist. In addition, we find that in both models, the time to extinction of the trait becomes longer as the number of role models per individual increases and as cultural transmission becomes more efficient.

Cooperative actions of Tbc1d1 and AS160/Tbc1d4 in GLUT4-trafficking activities.

AS160 and Tbc1d1 are key Rab GTPase-activating proteins (RabGAPs) that mediate release of static GLUT4 in response to insulin or exercise-mimetic stimuli, respectively, but their cooperative regulation and its underlying mechanisms remain unclear. By employing GLUT4 nanometry with cell-based reconstitution models, we herein analyzed the functional cooperative activities of the RabGAPs. When both RabGAPs are present, Tbc1d1 functionally dominates AS160, and stimuli-inducible GLUT4 release relies on Tbc1d1-evoking proximal stimuli, such as AICAR and intracellular Ca2+ Detailed functional assessments with varying expression ratios revealed that AS160 modulates sensitivity to external stimuli in Tbc1d1-mediated GLUT4 release. For example, Tbc1d1-governed GLUT4 release triggered by Ca2+ plus insulin occurred more efficiently than that in cells with little or no AS160. Series of mutational analyses revealed that these synergizing actions rely on the phosphotyrosine-binding 1 (PTB1) and calmodulin-binding domains of Tbc1d1 as well as key phosphorylation sites of both AS160 (Thr642) and Tbc1d1 (Ser237 and Thr596). Thus, the emerging cooperative governance relying on the multiple regulatory nodes of both Tbc1d1 and AS160, functioning together, plays a key role in properly deciphering biochemical signals into a physical GLUT4 release process in response to insulin, exercise, and the two in combination.

N-Heterocyclic Carbene-Catalyzed Decarboxylative Alkylation of Aldehydes.

We found that N-heterocyclic carbene catalysis promoted the unprecedented decarboxylative coupling of aryl aldehydes and tertiary or secondary alkyl carboxylic acid-derived redox-active esters to produce aryl alkyl ketones. The mild and transition-metal-free reaction conditions are attractive features of this method. The power of this protocol was demonstrated by the functionalization of pharmaceutical drugs and natural product. A reaction pathway involving single electron transfer from an enolate form of Breslow intermediate to a redox ester followed by recombination of the resultant radical pair to form a carbon-carbon bond is proposed.

N-Heterocyclic Carbene-Catalyzed Radical Relay Enabling Vicinal Alkylacylation of Alkenes.

The N-heterocyclic carbene-catalyzed radical relay enables the vicinal alkylacylation of styrenes, acrylates and acrylonitrile using aldehydes and tertiary alkyl carboxylic acid-derived redox-active esters. This protocol introduces tertiary alkyl groups and acyl groups to C-C double bonds with complete regioselectivity to produce functionalized ketone derivatives. The radical relay mechanism involves single electron transfer from the enolate form of a Breslow intermediate and radical addition of the resultant alkyl radical to the alkene followed by radical-radical coupling.

Synergistic N-Heterocyclic Carbene/Palladium-Catalyzed Reactions of Aldehyde Acyl Anions with either Diarylmethyl or Allylic Carbonates.

Benzylation and allylation of aldehyde acyl anions were enabled by the merger of a thiazolium N-heterocyclic carbene (NHC) catalyst and a palladium/bisphosphine catalyst in a synergistic manner. Owing to the mildness of the reaction conditions, various functional groups were tolerated in the substrates.

An Isolable Bismabenzene: Synthesis, Structure, and Reactivity.

A stable bismabenzene was synthesized, isolated, and structurally characterized. The prospective aromaticity of this heavy benzene, bearing a sixth-row element, was examined by X-ray crystallography and NMR and UV-vis spectroscopy, as well as theoretical DFT calculations. Structural analysis of this bismabenzene revealed a planar ring containing unsaturated Bi-C and C-C bonds. As bond alternations could not be observed, these results are consistent with the formal criteria of aromaticity. Theoretical calculations also support the aromatic nature of this bismabenzene, which reacted with an alkyne to form the corresponding [4+2] cycloadduct, thus demonstrating a small yet tangible aromatic stabilization energy.

Significance and Priority of Surgical Resection as Therapeutic Strategy Based on Clinical Characteristics of Brain Metastases from Renal Cell Carcinoma.

OBJECTIVE: To clarify a rational surgical priority, clinical characteristics were compared between brain metastases (BM) from renal cell carcinoma (RCC) and other cancers. METHODS: We reviewed 425 consecutive patients with BM who underwent treatments including surgery between January 2014 and December 2022. Primary cancers included lung (n = 220), breast (n = 46), digestive (n = 65), RCC (n = 25), and others (n = 69). Tumor volume (T), edema volume (E), and edema volume/tumor volume ratio (E/T ratio) were compared between RCC and other primary cancers. Cutoff T values for identifying both symptomatic tumors and tumors suitable for surgery were determined by receiver operating characteristic curves. Factors including E/T ratio, age, Karnofsky Performance Scale score, and tumor characteristics were statistically analyzed. RESULTS: Cutoff values of T and E to determine surgical suitability were 4.973 cm3 (sensitivity, 0.848; specificity, 0.74) and 23.088 cm3 (sensitivity, 0.894; specificity, 0.623), respectively. E/T ratio was significantly higher for RCC than for other cancers (P < 0.01). These results remained consistent after propensity score matching. RCC tended to show a significantly lower frequency of posterior fossa tumor (16%, P < 0.01) and higher rates of single lesions (72%, P = 0.03) and intratumoral hemorrhage (24%, P = 0.02). Subgroup analysis limited to surgical cases showed that E was consistent across tumors, T tended to be smaller, and E/T ratio was significantly higher in RCC. CONCLUSIONS: Generally, symptomatic BM were indicated for surgery. BM from RCC were characteristically single, low-volume lesions with expanding edema and intratumoral hemorrhage, causing symptoms. These results suggest that surgery should be a high priority for BM from RCC.

Transcriptional regulation of the Japanese flounder Cu,Zn-SOD (Jfsod1) gene in RAW264.7 cells during oxidative stress caused by causative bacteria of edwardsiellosis.

Edwardsiellosis is one of the most important bacterial diseases in fish, sometimes causing extensive economic losses in the aquaculture industry. Our previous studies demonstrated that the Cu,Zn-SOD (sod1) activity has significantly increased in Japanese flounder, Paralichthys olivaceus, hepatopancreas infected by causative bacteria of edwardsiellosis Edwardsiella tarda NUF251. In this study, NUF251 stimulated intracellular superoxide radical production in mouse macrophage RAW264.7 cells, which was reduced by N-acetylcysteine. This result suggests that NUF251 infection causes oxidative stress. To evaluate the regulatory mechanism of Jfsod1 at transcriptional levels under oxidative stress induced by NUF251 infection, we cloned and determined the nucleotide sequence (1124 bp) of the 5'-flanking region of the Jfsod1 gene. The sequence analysis demonstrated that the binding sites for the transcription factors C/EBPα and NF-IL6 involved in the transcriptional regulation of the mammalian sod1 gene existed. We constructed a luciferase reporter system with the 5'-flanking region (-1124/-1) of the Jfsod1 gene, and a highly increased transcriptional activity of the region was observed in NUF251-infected RAW264.7 cells. Further studies using several mutants indicated that deletion of the recognition region of NF-IL6 (-272/-132) resulted in a significant decrease in the transcriptional activity of the Jfsod1 gene in NUF251-infected RAW264.7 cells. In particular, the binding site (-202/-194) for NF-IL6 might play a major role in upregulating the transcriptional activity of the 5'-flanking region of the Jfsod1 gene in response to oxidative stress induced by NUF251 infection. These results could be provided a new insight to understand the pathogenic mechanism of causative bacteria of edwardsiellosis.

Diastereoselective [2+2] photocycloaddition of chiral cyclic enones with olefins in aqueous media using surfactants.

We conducted diastereodifferentiating [2+2] photocycloadditions of cyclo-hexenones modified with a chiral 8-(p-methoxy phenyl)menthyl auxiliary with olefins in water. Although the photoreaction didn't proceed at all in pure water owing to very low solubility, the use of surfactants [sodium dodecyl sulfate (SDS) or dodecylamine hydrochloride (DAH)] and additive (organic solvent) enabled the reactions to progress with moderate to high conversions and yields. Furthermore, we synthesized a new menthol derivative substrate containing a (p-octyloxy)phenyl group for enhancing hydrophobicity, and elucidated that this new substrate was found to be a suitable chiral auxiliary in this asymmetric photoreaction in aqueous system. The additive effect of organic molecules on the yield and diastereoselectivity of the photo-adducts is also discussed.

Encephalo-Arterio-Synangiosis with Cranioplasty after Treatment of Acute Subdural Hematoma Associated with Subcortical Hemorrhage Due to Unilateral Moyamoya Disease.

Moyamoya disease is often diagnosed after intracranial hemorrhage in adult patients. Here, we report a case of unilateral moyamoya disease treated with indirect revascularization combined with cranioplasty after treatment for acute subdural hematoma and subcortical hemorrhage. A middle-aged woman with disturbed consciousness was transferred to our hospital. Computed tomography (CT) revealed an acute subdural hematoma with left temporoparietal subcortical hemorrhage. Three-dimensional CT angiography indicated a scarcely enhanced left middle cerebral artery (MCA) that was suspected to be delayed or nonfilling due to increased intracranial pressure. Subsequently, hematoma evacuation and external decompression were performed. Postoperative digital subtraction angiography (DSA) revealed stenosis of the left MCA and moyamoya vessels, indicating unilateral moyamoya disease. Forty-five days after the initial procedure, we performed encephalo-arterio-synangiosis (EAS) using the superficial temporal artery simultaneously with cranioplasty for the skull defect. The modified Rankin Scale score of the patient one year after discharge was 1, and the repeat DSA showed good patency of the EAS. Revascularization using EAS in the second step can be an option for revascularization for hemorrhagic moyamoya disease if the patient required cranioplasty for postoperative skull defect after decompressive craniotomy.

Real Stiffness and Vividness Reproduction of Anatomic Structures Into the 3-Dimensional Printed Models Contributes to Improved Simulation and Training in Skull Base Surgery.

BACKGROUND: Despite the advancement of 3-dimensional (3D) printing technology with medical application, its neurosurgical utility value has been limited to understanding the anatomy of bones, lesions, and their surroundings in the neurosurgical field. OBJECTIVE: To develop a 3D printed model simulating the surgical technique applied in skull base surgery (SBS), especially to reproduce visually the surgical field together with the mechanical properties of tissues as perceived by the surgeon through procedures performance on a model. METHODS: The Young modulus representing the degree of stiffness was measured for the tissues of anesthetized animals and printing materials. The stiffness and vividness of models were adjusted appropriately for each structure. Empty spaces were produced inside the models of brains, venous sinuses, and tumors. The 3D printed models were created in 7 cases of SBS planned patients and were used for surgical simulation. RESULTS: The Young modulus of pig's brain ranged from 5.56 to 11.01 kPa and goat's brain from 4.51 to 13.69 kPa, and the dura of pig and goat values were 14.00 and 24.62 kPa, respectively. Although the softest printing material had about 20 times of Young modulus compared with animal brain, the hollow structure of brain model gave a soft sensation resembling the real organ and was helpful for bridging the gap between Young moduli values. A dura/tentorium-containing model was practical to simulate the real maneuverability at surgery. CONCLUSION: The stiffness/vividness modulated 3D printed model provides an advanced realistic environment for training and simulation of a wide range of SBS procedures.

[Diagnosis of patients with thoracic outlet syndrome (TOS) using physiological measures of the medial antebrachial cutaneous nerve].

The diagnosis of thoracic outlet syndrome (TOS) remains difficult; therefore, reliable and objective tests are required. We examined the process to diagnose TOS, and assessed the validity of measuring the medial antebrachial cutaneous nerve (MAC), also the ulnar nerve (UN) as a diagnostic tool. Between 2008 and 2011, 86 sides in 73 patients admitted to our hospital for the treatment of TOS were analyzed. In the process for the diagnosis as TOS, the narrow parts of the subclavian artery that was compressed by the anterior scalene muscle were confirmed with a three-dimensional CT angiography. All patients were taken a brachial plexus anesthesiological block to aim at both for diagnosis and treatment of TOS. For the diagnosis of TOS, measurements of latency (LT) and sensory nerve action potential (SNAP) of MAC and UN were analyzed between the TOS side and the non-TOS side and separated into traumatic type or disputed type. In our research, the LT of MAC and UN did not differ much between the TOS side and the non-TOS side; however, the amplitude of SNAP of MAC and UN were lower on the TOS side, especially in traumatic TOS. We concluded that comparison of the amplitude of SNAP of MAC on the injured or non-injured side was comparatively helpful for the diagnosis of TOS.

5-Aminolevulinic acid and sodium ferrous citrate ameliorate muscle aging and extend healthspan in Drosophila.

Declines in mitochondrial functions are associated with aging. The combination of 5-aminolevulinic acid (5-ALA) and sodium ferrous citrate (SFC) improves mitochondrial functions in cultured cells. In this study, we investigated the effects of dietary supplementation with 5-ALA and SFC (5-ALA/SFC) on the healthspan and life span of Drosophila melanogaster. Adult Drosophila fruit flies were fed cornmeal food containing various concentrations of 5-ALA/SFC. Locomotor functions, life span, muscle architecture, and age-associated changes in mitochondrial function were analyzed. We found that feeding 5-ALA/SFC mitigated age-associated declines in locomotor functions and extended organismal life span. Moreover, 5-ALA/SFC preserved muscle architecture and maintained the mitochondrial membrane potential in aged animals. Since 5-ALA phosphate/SFC is used as a human dietary supplement, our results suggest that it could be used to slow the age-related declines in muscle functions, prevent age-associated clinical conditions such as frailty, and extend healthspan and life span.

Subclavian Artery Flow Dynamics Evaluated by Analytical Intraoperative Indocyanine Green Videoangiography During Surgical Treatment of Thoracic Outlet Syndrome: A Case Series.

BACKGROUND: Indocyanine green (ICG) videoangiography is rarely used during the surgical treatment of thoracic outlet syndrome (TOS). OBJECTIVE: To evaluate subclavian artery (SA) flow dynamics using the analytical ICG videoangiography during TOS surgeries. METHODS: We examined patients with neurogenic TOS who received surgical treatment and whose SA blood flow at the interscalene space was evaluated using ICG videoangiography equipped with an analytical function (FLOW800). Anterior scalenectomy with or without middle scalenectomy and first rib resection were conducted for decompression of the brachial plexus. ICG videoangiography was performed before and after decompression of the brachial plexus. After acquisition of grayscale and color-coded maps, a region of interest was placed in the SA to obtain time-intensity diagrams. Maximum intensity (MI), rise time (RT), and blood flow index (BFi) were calculated from the diagram, in arbitrary intensity (AI) units. We compared values before and after decompression. Comparisons of the three parameters before and after decompression were assessed statistically using the paired t-tests and Wilcoxon signed-rank test. RESULTS: We evaluated nine procedures in consecutively presenting patients. The observed mean values of MI, RT, and BFi before decompression were 174.1 ± 61.5 AI, 5.2 ± 1.1 s, and 35.2 ± 13.5 AI/s, respectively, and the observed mean values of MI, RT, and BFi after decompression were 299.3 ± 167.4 AI, 6.6 ± 0.8 s, and 44.6 ± 28.3 AI/s, respectively. These parameters showed higher values after decompression than before decompression, and the increase in MI and RT was statistically significant (P < .05). CONCLUSION: ICG videoangiography allows semiquantitative evaluation of hemodynamic changes during TOS surgery. A marked decrease in the velocity of SA flow was observed after decompression.

5-Aminolevulinic acid combined with ferrous iron improves glucose tolerance in high-fat diet-fed mice via upregulation of glucose transporter 1.

Decreased mitochondrial metabolism suppresses glucose metabolism, resulting in obesity and diabetes. The present study aimed to investigate mechanisms underlying the 5-aminolevulinic acid (5-ALA) hydrochloride-mediated increase in glucose uptake in high-fat diet (HFD)-fed mice in vivo and C2C12 myotube cells in vitro. C57BL/6N male mice (20 weeks old) were fed either HFD or normal diet (ND) for 4 weeks. A total of five HFD-fed mice were orally administered with 300 mg/kg 5-ALA hydrochloride and 47.1 mg/kg sodium ferrous citrate (SFC; HFD + 5-ALA/SFC), whereas ND and other HFD-fed mice were orally administered with saline. After 4 weeks, these mice were intraperitoneally administered with 2 g/kg glucose and 3.2 mg/kg 2-deoxyglucose (2DG) for intraperitoneal glucose tolerance test (IPGTT) and glucose uptake test. Body weights, plasma glucose levels and the area under the curve of IPGTT were lower in mice treated with HFD + 5-ALA/SFC compared with in those treated with HFD alone. 2DG uptake in the gastrocnemius muscle and heart were more significantly improved in the HFD + 5-ALA/SFC mice compared with the HFD-fed mice. Furthermore, 5-ALA/SFC increased 2DG uptake in C2C12 cells to a similar level to the insulin-treated group. Moreover, it increased glucose transport (GLUT)1 translocation in the plasma membrane by 2.5-fold relative to the controls without affecting GLUT1 expression; however, it had no effect on GLUT4 translocation. Therefore, 5-ALA/SFC enhanced gastrocnemius and cardiac glucose uptake in HFD-fed mice, and upregulated GLUT1 translocation to the plasma membrane, but not GLUT4 in C2C12 myotube cells. Therefore, it could potentially be used as a novel drug for the treatment of diabetes.

Aryl radical-mediated N-heterocyclic carbene catalysis.

There have been significant advancements in radical reactions using organocatalysts in modern organic synthesis. Recently, NHC-catalyzed radical reactions initiated by single electron transfer processes have been actively studied. However, the reported examples have been limited to catalysis mediated by alkyl radicals. In this article, the NHC organocatalysis mediated by aryl radicals has been achieved. The enolate form of the Breslow intermediate derived from an aldehyde and thiazolium-type NHC in the presence of a base undergoes single electron transfer to an aryl iodide, providing an aryl radical. The catalytically generated aryl radical could be exploited as an arylating reagent for radical relay-type arylacylation of styrenes and as a hydrogen atom abstraction reagent for α-amino C(sp3)-H acylation of secondary amides.

Mechanism of Differential Susceptibility of Two (Canine Lung Adenocarcinoma) Cell Lines to 5-Aminolevulinic Acid-Mediated Photodynamic Therapy.

Photodynamic therapy (PDT) is a clinically approved, minimally invasive treatment for malignant tumors. Protoporphyrin IX (PpIX), derived from 5-aminolevulinic acid (5-ALA) as the prodrug, is one of the photosensitizers used in PDT. Recently, we reported a significant difference in response to 5-ALA-mediated PDT treatment in two canine primary lung adenocarcinoma cell lines (sensitive to PDT: HDC cells, resistant to PDT: LuBi cells). This study aimed to examine the difference in cytotoxicity of 5-ALA-mediated PDT in these cells. Although intracellular PpIX levels before irradiation were similar between HDC and LuBi cells, the percentage of ROS-positive cells and apoptotic cells in LuBi cells treated with 5-ALA-mediated PDT was significantly lower than that in HDC cells treated with 5-ALA-mediated PDT. A high dosage of the NO donor, DETA NONOate, significantly increased the cytotoxicity of 5-ALA-mediated PDT against LuBi cells. These results suggest that the sensitivity of 5-ALA-mediated PDT might be correlated with NO.