The enhancement of riboflavin-mediated photo-oxidation of doxorubicin by histidine and urocanic acid

PURPOSE: Previously we have shown that doxorubicin (Adriamycin, ADR) can be inactivated by light-excited riboflavin. The inactivation of the drug results from its direct oxidation by the excited triplet riboflavin in a type I photosensitization reaction, and 3-methoxysalicyclic acid is an ADR breakdown product. In the present study, we investigated the enhancement of this process by histidine and some other imidazole analogs. METHODS: ADR solutions containing various concentrations of riboflavin and other agents were exposed to 365 nm light for various time periods and then the absorbance spectrum of ADR was measured by a double beam spectrophotometer. These measurement were used to calculate the half-time of the ADR degradation process. The degraded ADR solutions were analyzed by HPLC. RESULTS: The rate of bleaching of ADR by light-excited riboflavin was enhanced in the presence of histidine in a concentration-dependent manner. This enhancement was more pronounced at higher riboflavin concentrations. Histidine also enhanced the riboflavin-mediated photobleaching of N,N-dimethyl-4-nitrosoaniline (RNO), a compound known to be resistant to oxidation by singlet oxygen but sensitive to oxidation by the trans-annular peroxide of histidine. RNO was found to block the histidine enhancement of the riboflavin-mediated photobleaching of ADR in a competitive manner. Among the imidazole analogs of histidine tested, urocanic acid was found to be the most efficient enhancer of the riboflavin-mediated photobleaching of ADR. Superoxide anion radicals which retard the oxidation of ADR were quenched by urocanic acid but not by histidine. It was shown that the oxidation of ADR by the trans-annular peroxide of histidine resulted in the formation of 3-methoxysalicylic acid. CONCLUSIONS: In contrast to singlet oxygen, the trans-annular peroxide, formed by the interaction of histidine and the singlet oxygen produced by photoexcited riboflavin, is an efficient oxidizer of ADR. The enhancement of the riboflavin-mediated photobleaching of ADR by histidine analogs depends on the rate of their conversion to a trans-annular peroxide and on the efficiency of these products in oxidizing ADR. However, for some analogs of histidine, as shown for urocanic acid, other mechanisms could also be involved. The presence of urocanic acid in the skin suggests that significant degradation of ADR could occur in the presence of biologically relevant concentrations of riboflavin if patients treated with ADR are exposed to sunlight. The finding that histidine also enhanced the degradation of ADR to 3-methoxysalicylic acid, suggests that the process of ADR oxidation by the trans-annular peroxides is similar to the direct oxidation of ADR by excited triplet riboflavin.     

Enhancing cervical cancer detection using nucleic acid hybridization and acetic acid tests

Acetowhitening of abnormal cervical epithelium has been suggested as an indicator of increased cervical cancer risk. The presence of human papillomavirus (HPV) types 16, 18, 31, 33 and 35 may also indicate increased cervical cancer risk. Hence, tests that detect these two abnormal conditions may augment that Papanicolaou smear (Pap test) as predictors of cervical cancer risk. The cohort consisted of 145 women aged 14 to 47 (mean 21 years) attending health clinics. Thirty women (20.6 percent) showed acetowhitening of the cervical epithelium following exposure to vinegar of 4-percent acetic acid content. Fourteen (9.6 percent) had a positive Pap test and 13 (9 percent) carried a cervical HPV infection as determined by the commercially available ViraPap and ViraType nucleic acid tests. Statistical analysis of the data showed a positive correlation between Pap, ViraPap and acetic acid tests results. The acetic acid test and the nucleic acid tests were the sole positive tests for 21 (14.5 percent) and nine (6.2 percent) women, respectively. Four women with negative Pap results were infected with HPV types previously shown to have an association with cervical intraepithelial neoplasias, carcinoma in situ and cervical cancer. The authors have concluded that the acetic acid and nucleic acid tests detect women at risk for cervical cancer who would not have been detected by the Pap test alone.     

Genetic association study of the P‐type ATPase ATP13A2 in late‐onset Parkinson's disease

A role of ATP13A2 in early‐onset Parkinsonism (EOP) has been proposed. Conversely, the contribution of this ATPase to late‐onset Parkinson's disease (PD) remains unexplored. We therefore conducted a case–control association study in this age‐of‐onset group with PD. The initial sample was of German origin and consisted of 220 patients with late‐onset PD (mean age of onset 60.1 years) and 232 age‐matched unrelated controls. Five single nucleotide polymorphisms (SNPs) covering ATP13A2 and its common haplotypes were genotyped. The overall association results in this sample were negative. Interestingly, gender stratification gave a positive result for SNP rs11203280 (P_UNC = 0.016) in men. This result could not be reproduced in a replication sample of German and Serbian origin composed of 161 patients with late‐onset PD (mean age of onset 51.7 years) and 150 age‐ and ethnic‐matched controls. In conclusion, we found no consistent evidence for an association between ATP13A2 and late‐onset PD. © 2008 Movement Disorder Society     

Latissimus dorsi-scapula free flap for reconstruction of defects following radical maxillectomy with orbital exenteration.

A total of 21 patients with latissimus dorsi-scapula free flap reconstruction immediately following radical maxillectomy together with orbital exenteration are presented. Orbital exenteration was performed in all patients due to tumour invasion at the time of diagnosis. There was no total flap failure. Two tissue components subdivided into separate flap units with individual vascular pedicles linked by a single vascular source provide an ideal reconstructive solution for massive defects of the mid-face and orbit. Separate arcs of rotation of each flap unit permit greater mobility necessary for complex three-dimensional reconstruction. A vertically positioned angle of the scapula enables simultaneous reconstruction of the malar eminence and alveolar ridge whereas spontaneous intraoral epithelialisation of the latissimus dorsi muscle requires no additional procedure. For these reasons, in our opinion, combined latissimus dorsi-scapula free flap should be considered the first choice in reconstruction of defects following total maxillectomy with orbital exenteration.     

Procalcitonin in preoperative diagnosis of abdominal sepsis

Background and aims The present study attempted to identify the diagnostic significance of procalcitonin (PCT) in acute abdominal conditions as well as the range of concentrations relating to diagnosis of abdominal sepsis. Materials and methods This was prospective clinical study. The study included 98 consecutive patients with acute abdominal conditions, divided in sepsis and systemic inflammatory response syndrome (SIRS) group. Results PCT concentrations on admission were significantly higher in the sepsis group than in the SIRS group (median [interquartile range] 2.32 [7.41] vs 0.45 ng/ml [2.62]). A cutoff value of 1.1 ng/ml yielded 72.4% sensitivity and 62.5% specificity. In a group of patients with abdominal symptoms lasting for more than 24 h, a cut-off value of 1.1 ng/ml yielded higher sensitivity (82.9%) and higher specificity (77.3%). Conclusion Our results suggest that PCT measurements may be useful for early, preoperative diagnosis of abdominal sepsis.     

In vitro function and phagocytosis of galactosylated platelet concentrates after long-term refrigeration

BACKGROUND: Short-term refrigeration of platelets (PLTs) in the absence of plasma results in their rapid clearance after transfusion. Blocking beta-N-acetylglucosamine (beta-GlcNAc) residues of glycoprotein Ibalpha (GPIbalpha) with galactose prevents binding of refrigerated human and mouse PLTs to macrophages and prolongs the circulation times of refrigerated mouse PLTs. PLT-associated galactosyltransferase efficiently galactosylates chilled PLTs in the presence of its substrate UDP-galactose is added to PLT-rich plasma. STUDY DESIGN AND METHODS: To characterize the hemostatic function of refrigerated and galactosylated human PLTs processed in the blood bank, PLT aggregation was studied in vitro under static and flow conditions and expression of integrin beta3 (CD61), CD62P (P-selectin), GPIbalpha (CD42b), annexin V binding, and integrin alphaIIbeta3 activation with flow cytometry. Affinity of macrophages for galactosylated refrigerated PLTs was evaluated with THP-1 cells, which recognize and phagocytize refrigerated PLTs. RESULTS: PLTs refrigerated and galactosylated for 14 days 1) maintained their ability to aggregate when exposed to agonists in a standard aggregometry assay, 2) showed less pronounced changes in surface expression of GPIbalpha compared with room temperature (RT)-stored PLTs, 3) increased P-selectin expression, and 4) were poorly phagocytized by differentiated THP-1 cells in vitro. In addition, it is shown that refrigeration of PLTs does not affect their adhesive properties under in vitro flow conditions. CONCLUSION: It is shown that refrigerated human PLTs retain in vitro function better than RT PLTs during storage and demonstrate that galactosylation prevents recognition of stored refrigerated PLTs by macrophages in vitro.     

CD1d-restricted human natural killer T cells are highly susceptible to human immunodeficiency virus 1 infection

Human natural killer (NK) T cells are unique T lymphocytes that express an invariant T cell receptor (TCR) Valpha24-Vbeta11 and have been implicated to play a role in various diseases. A subset of NKT cells express CD4 and hence are potential targets for human immunodeficiency virus (HIV)-1 infection. We demonstrate that both resting and activated human Valpha24(+) T cells express high levels of the HIV-1 coreceptors CCR5 and Bonzo (CXCR6), but low levels of CCR7, as compared with conventional T cells. Remarkably NKT cells activated with alpha-galactosylceramide (alpha-GalCer)-pulsed dendritic cells were profoundly more susceptible to infection with R5-tropic, but not X4-tropic, strains of HIV-1, compared with conventional CD4(+) T cells. Furthermore, resting CD4(+) NKT cells were also more susceptible to infection. After initial infection, HIV-1 rapidly replicated and depleted the CD4(+) subset of NKT cells. In addition, peripheral blood NKT cells were markedly and selectively depleted in HIV-1 infected individuals. Although the mechanisms of this decline are not clear, low numbers or absence of NKT cells may affect the course of HIV-1 infection. Taken together, our findings indicate that CD4(+) NKT cells are directly targeted by HIV-1 and may have a potential role during viral transmission and spread in vivo.