Double-strand breaks in heterochromatin move outside of a dynamic HP1a domain to complete recombinational repair.

Double-strand breaks (DSBs) in heterochromatic repetitive DNAs pose significant threats to genome integrity, but information about how such lesions are processed and repaired is sparse. We observe dramatic expansion and dynamic protrusions of the heterochromatin domain in response to ionizing radiation (IR) in Drosophila cells. We also find that heterochromatic DSBs are repaired by homologous recombination (HR) but with striking differences from euchromatin. Proteins involved in early HR events (resection) are rapidly recruited to DSBs within heterochromatin. In contrast, Rad51, which mediates strand invasion, only associates with DSBs that relocalize outside of the domain. Heterochromatin expansion and relocalization of foci require checkpoint and resection proteins. Finally, the Smc5/6 complex is enriched in heterochromatin and is required to exclude Rad51 from the domain and prevent abnormal recombination. We propose that the spatial and temporal control of DSB repair in heterochromatin safeguards genome stability by preventing aberrant exchanges between repeats.

Mitochondrial targeting of XJB-5-131 attenuates or improves pathophysiology in HdhQ150 animals with well-developed disease phenotypes.

Oxidative damage to mitochondria (MT) is a major mechanism for aging and neurodegeneration. We have developed a novel synthetic antioxidant, XJB-5-131, which directly targets MT, the primary site and primary target of oxidative damage. XJB-5-131 prevents the onset of motor decline in an HdhQ(150/150) mouse model for Huntington's disease (HD) if treatment starts early. Here, we report that XJB-5-131 attenuates or reverses disease progression if treatment occurs after disease onset. In animals with well-developed pathology, XJB-5-131 promotes weight gain, prevents neuronal death, reduces oxidative damage in neurons, suppresses the decline of motor performance or improves it, and reduces a graying phenotype in treated HdhQ(150/150) animals relative to matched littermate controls. XJB-5-131 holds promise as a clinical candidate for the treatment of HD.

Evidence for formation of DNA repair centers and dose-response nonlinearity in human cells.

The concept of DNA "repair centers" and the meaning of radiation-induced foci (RIF) in human cells have remained controversial. RIFs are characterized by the local recruitment of DNA damage sensing proteins such as p53 binding protein (53BP1). Here, we provide strong evidence for the existence of repair centers. We used live imaging and mathematical fitting of RIF kinetics to show that RIF induction rate increases with increasing radiation dose, whereas the rate at which RIFs disappear decreases. We show that multiple DNA double-strand breaks (DSBs) 1 to 2 µm apart can rapidly cluster into repair centers. Correcting mathematically for the dose dependence of induction/resolution rates, we observe an absolute RIF yield that is surprisingly much smaller at higher doses: 15 RIF/Gy after 2 Gy exposure compared to approximately 64 RIF/Gy after 0.1 Gy. Cumulative RIF counts from time lapse of 53BP1-GFP in human breast cells confirmed these results. The standard model currently in use applies a linear scale, extrapolating cancer risk from high doses to low doses of ionizing radiation. However, our discovery of DSB clustering over such large distances casts considerable doubts on the general assumption that risk to ionizing radiation is proportional to dose, and instead provides a mechanism that could more accurately address risk dose dependency of ionizing radiation.

Capecitabine in combination with oxaliplatin and bevacizumab (AXELOX) as 1st line treatment for fit and vulnerable elderly patients (aged >70 years) with metastatic colorectal cancer (mCRC): a multicenter phase II study of the Hellenic Oncology Research Group (HORG).

BACKGROUND: Colorectal cancer (CRC) is a disease of the elderly. However, geriatric patients are often excluded from clinical trials. The combination of capecitabine, oxaliplatin and bevacizumab (XELOX/BEV) has not been assessed in an elderly population. METHODS: We conducted a phase II study of XELOX plus bevacizumab combination as first line treatment in elderly patients with metastatic CRC. Treatment consisted of capecitabine 750 mg/m2 twice a day during days 1-7, oxaliplatin 85 mg/m2 and bevacizumab 5 mg/kg on day 1. Treatment was repeated every 14 days. The primary endpoint was overall response rate. RESULTS: In the 48 enrolled patients response rate according was 46.8% (95% CI: 32.54%-61.07%), while 13 patients had stable disease, for an overall disease control rate of 74.4% (95% CI: 57.8-91.2). Progression free survival was 7.9 months (95% CI: 5.9-9.8 months) and the median overall survival 20.1 months (95% CI: 15.6-25.7 months). Response rate and progression free survival has been correlated with baseline albumin and haemoglobin levels. There was one treatment-related death. Grade 3-4 toxicities were asthenia (4.2%), neurotoxicity (2.1%) and diarrhea 6.3%). CONCLUSIONS: The combination of capecitabine, oxaliplatin and bevacizumab is an effective and safe combination for the treatment of elderly patients with metastatic CRC. TRIAL REGISTRATION: Clinical trials NCT01024504, 26 November 2010.

Analysis of human invasive cytotrophoblasts using multicolor fluorescence in situ hybridization.

Multicolor fluorescence in situ hybridization, or FISH, is a widely used method to assess fixed tissues or isolated cells for numerical and structural chromosome aberrations. Unlike other screening procedures which provide average chromosome numbers for heterogeneous samples, FISH is a sensitive cell-by-cell method to analyze the distribution of abnormal cells in complex tissues. Here, we applied FISH to characterize chromosomal composition of a rare, but very important class of human cells that stabilize the fetal-maternal interface connecting the placenta to the uterine wall during early pregnancy, called invasive cytotrophoblasts (iCTBs). Combining differently-labeled, chromosome-specific DNA probes, we were able to unambiguously determine the number of up to six different autosomes and gonosomes in individual cell nuclei from iCTBs selected on the basis of their invasive behavior. In this manuscript, we describe a method for generation of iCTBs from placental villi, and provide the complete workflow of our FISH experiments including a detailed description of reagents and a trouble-shooting guide. We also include an in-depth discussion of the various types and sources of DNA probes which have evolved considerably in the last two decades. Thus, this communication represents both a complete guide as well as a valuable resource, intended to allow an average laboratory to reproduce the experiments and minimize the amount of specialized, and often costly, equipment.

Sidestream tobacco smoke is a male germ cell mutagen.

Active cigarette smoking increases oxidative damage, DNA adducts, DNA strand breaks, chromosomal aberrations, and heritable mutations in sperm. However, little is known regarding the effects of second-hand smoke on the male germ line. We show here that short-term exposure to mainstream tobacco smoke or sidestream tobacco smoke (STS), the main component of second-hand smoke, induces mutations at an expanded simple tandem repeat locus (Ms6-hm) in mouse sperm. We further show that the response to STS is not linear and that, for both mainstream tobacco smoke and STS, doses that induced significant increases in expanded simple tandem repeat mutations in sperm did not increase the frequencies of micronucleated reticulocytes and erythrocytes in the bone marrow and blood of exposed mice. These data show that passive exposure to cigarette smoke can cause tandem repeat mutations in sperm under conditions that may not induce genetic damage in somatic cells. Although the relationship between noncoding tandem repeat instability and mutations in functional regions of the genome is unclear, our data suggest that paternal exposure to second-hand smoke may have reproductive consequences that go beyond the passive smoker.

Bioinformatic Tools Identify Chromosome-Specific DNA Probes and Facilitate Risk Assessment by Detecting Aneusomies in Extra-embryonic Tissues.

Despite their non-diseased nature, healthy human tissues may show a surprisingly large fraction of aneusomic or aneuploid cells. We have shown previously that hybridization of three to six non-isotopically labeled, chromosome-specific DNA probes reveals different proportions of aneuploid cells in individual compartments of the human placenta and the uterine wall. Using fluorescence in situ hybridization, we found that human invasive cytotrophoblasts isolated from anchoring villi or the uterine wall had gained individual chromosomes. Chromosome losses in placental or uterine tissues, on the other hand, were detected infrequently. A more thorough numerical analysis of all possible aneusomies occurring in these tissues and the investigation of their spatial as well as temporal distribution would further our understanding of the underlying biology, but it is hampered by the high cost of and limited access to DNA probes. Furthermore, multiplexing assays are difficult to set up with commercially available probes due to limited choices of probe labels. Many laboratories therefore attempt to develop their own DNA probe sets, often duplicating cloning and screening efforts underway elsewhere. In this review, we discuss the conventional approaches to the preparation of chromosome-specific DNA probes followed by a description of our approach using state-of-the-art bioinformatics and molecular biology tools for probe identification and manufacture. Novel probes that target gonosomes as well as two autosomes are presented as examples of rapid and inexpensive preparation of highly specific DNA probes for applications in placenta research and perinatal diagnostics.

Heterozygosity for a Bub1 mutation causes female-specific germ cell aneuploidy in mice.

Aneuploidy, the most common chromosomal abnormality at birth and the main ascertained cause of pregnancy loss in humans, originates primarily from chromosome segregation errors during oogenesis. Here, we report that heterozygosity for a mutation in the mitotic checkpoint kinase gene, Bub1, induces aneuploidy in female germ cells of mice and that the effect increases with advancing maternal age. Analysis of Bub1 heterozygous oocytes showed that aneuploidy occurred primarily during the first meiotic division and involved premature sister chromatid separation. Furthermore, aneuploidy was inherited in zygotes and resulted in the loss of embryos after implantation. The incidence of aneuploidy in zygotes was sufficient to explain the reduced litter size in matings with Bub1 heterozygous females. No effects were seen in germ cells from heterozygous males. These findings show that Bub1 dysfunction is linked to inherited aneuploidy in female germ cells and may contribute to the maternal age-related increase in aneuploidy and pregnancy loss.

Chromosome-specific DNA repeats: rapid identification in silico and validation using fluorescence in situ hybridization.

Chromosome enumeration in interphase and metaphase cells using fluorescence in situ hybridization (FISH) is an established procedure for the rapid and accurate cytogenetic analysis of cell nuclei and polar bodies, the unambiguous gender determination, as well as the definition of tumor-specific signatures. Present bottlenecks in the procedure are a limited number of commercial, non-isotopically labeled probes that can be combined in multiplex FISH assays and the relatively high price and effort to develop additional probes. We describe a streamlined approach for rapid probe definition, synthesis and validation, which is based on the analysis of publicly available DNA sequence information, also known as "database mining". Examples of probe preparation for the human gonosomes and chromosome 16 as a selected autosome outline the probe selection strategy, define a timeline for expedited probe production and compare this novel selection strategy to more conventional probe cloning protocols.

A Double-Pronged Sword: XJB-5-131 Is a Suppressor of Somatic Instability and Toxicity in Huntington's Disease.

Due to large increases in the elderly populations across the world, age-related diseases are expected to expand dramatically in the coming years. Among these, neurodegenerative diseases will be among the most devastating in terms of their emotional and economic impact on patients, their families, and associated subsidized health costs. There is no currently available cure or rescue for dying brain cells. Viable therapeutics for any of these disorders would be a breakthrough and provide relief for the large number of affected patients and their families. Neurodegeneration is accompanied by elevated oxidative damage and inflammation. While natural antioxidants have largely failed in clinical trials, preclinical phenotyping of the unnatural, mitochondrial targeted nitroxide, XJB-5-131, bodes well for further translational development in advanced animal models or in humans. Here we consider the usefulness of synthetic antioxidants for the treatment of Huntington's disease. The mitochondrial targeting properties of XJB-5-131 have great promise. It is both an electron scavenger and an antioxidant, reducing both somatic expansion and toxicity simultaneously through the same redox mechanism. By quenching reactive oxygen species, XJB-5-131 breaks the cycle between the rise in oxidative damage during disease progression and the somatic growth of the CAG repeat which depends on oxidation.

Flap Endonuclease 1 Endonucleolytically Processes RNA to Resolve R-Loops through DNA Base Excision Repair.

Flap endonuclease 1 (FEN1) is an essential enzyme that removes RNA primers and base lesions during DNA lagging strand maturation and long-patch base excision repair (BER). It plays a crucial role in maintaining genome stability and integrity. FEN1 is also implicated in RNA processing and biogenesis. A recent study from our group has shown that FEN1 is involved in trinucleotide repeat deletion by processing the RNA strand in R-loops through BER, further suggesting that the enzyme can modulate genome stability by facilitating the resolution of R-loops. However, it remains unknown how FEN1 can process RNA to resolve an R-loop. In this study, we examined the FEN1 cleavage activity on the RNA:DNA hybrid intermediates generated during DNA lagging strand processing and BER in R-loops. We found that both human and yeast FEN1 efficiently cleaved an RNA flap in the intermediates using its endonuclease activity. We further demonstrated that FEN1 was recruited to R-loops in normal human fibroblasts and senataxin-deficient (AOA2) fibroblasts, and its R-loop recruitment was significantly increased by oxidative DNA damage. We showed that FEN1 specifically employed its endonucleolytic cleavage activity to remove the RNA strand in an R-loop during BER. We found that FEN1 coordinated its DNA and RNA endonucleolytic cleavage activity with the 3'-5' exonuclease of APE1 to resolve the R-loop. Our results further suggest that FEN1 employed its unique tracking mechanism to endonucleolytically cleave the RNA strand in an R-loop by coordinating with other BER enzymes and cofactors during BER. Our study provides the first evidence that FEN1 endonucleolytic cleavage can result in the resolution of R-loops via the BER pathway, thereby maintaining genome integrity.

Germ-line mutations, DNA damage, and global hypermethylation in mice exposed to particulate air pollution in an urban/industrial location.

Particulate air pollution is widespread, yet we have little understanding of the long-term health implications associated with exposure. We investigated DNA damage, mutation, and methylation in gametes of male mice exposed to particulate air pollution in an industrial/urban environment. C57BL/CBA mice were exposed in situ to ambient air near two integrated steel mills and a major highway, alongside control mice breathing high-efficiency air particulate (HEPA) filtered ambient air. PCR analysis of an expanded simple tandem repeat (ESTR) locus revealed a 1.6-fold increase in sperm mutation frequency in mice exposed to ambient air for 10 wks, followed by a 6-wk break, compared with HEPA-filtered air, indicating that mutations were induced in spermatogonial stem cells. DNA collected after 3 or 10 wks of exposure did not exhibit increased mutation frequency. Bulky DNA adducts were below the detection threshold in testes samples, suggesting that DNA reactive chemicals do not reach the germ line and cause ESTR mutation. In contrast, DNA strand breaks were elevated at 3 and 10 wks, possibly resulting from oxidative stress arising from exposure to particles and associated airborne pollutants. Sperm DNA was hypermethylated in mice breathing ambient relative to HEPA-filtered air and this change persisted following removal from the environmental exposure. Increased germ-line DNA mutation frequencies may cause population-level changes in genetic composition and disease. Changes in methylation can have widespread repercussions for chromatin structure, gene expression and genome stability. Potential health effects warrant extensive further investigation.

An infrared spectral biomarker accurately predicts neurodegenerative disease class in the absence of overt symptoms.

Although some neurodegenerative diseases can be identified by behavioral characteristics relatively late in disease progression, we currently lack methods to predict who has developed disease before the onset of symptoms, when onset will occur, or the outcome of therapeutics. New biomarkers are needed. Here we describe spectral phenotyping, a new kind of biomarker that makes disease predictions based on chemical rather than biological endpoints in cells. Spectral phenotyping uses Fourier Transform Infrared (FTIR) spectromicroscopy to produce an absorbance signature as a rapid physiological indicator of disease state. FTIR spectromicroscopy has over the past been used in differential diagnoses of manifest disease. Here, we report that the unique FTIR chemical signature accurately predicts disease class in mouse with high probability in the absence of brain pathology. In human cells, the FTIR biomarker accurately predicts neurodegenerative disease class using fibroblasts as surrogate cells.

A multicenter phase II trial with irinotecan plus oxaliplatin as first-line treatment for inoperable/metastatic cancer of the biliary tract.

PURPOSE: To evaluate the efficacy and tolerability of oxaliplatin (L-OHP) in combination with irinotecan (CPT-11) as first-line treatment of advanced biliary tract cancer. PATIENTS AND METHODS: Patients with histologically confirmed nonresectable biliary adenocarcinoma were treated with oxaliplatin (85 mg/m(2)) and irinotecan (200 mg/m(2)) every 3 weeks. RESULTS: Twenty-eight patients were enrolled between May 2005 and March 2009. The overall objective response rate was 17.9% with an additional 21.4% of patients with stable disease (disease control rate 39.3%). The median overall survival time was 9.2 months (95% CI 5.8-12.5) and the median progression-free survival time 2.7 months (95% CI 2.2-3.2). Grades 3 and 4 neutropenia occurred in 1 (3.6%) and 4 (14.3%) patients, respectively, and febrile neutropenia in 3 (10.7%). Grade 3-4 diarrhea was observed in 2 (7.1%) patients and grade 3 asthenia in 1 (6%). There were no treatment-related deaths. CONCLUSION: The combination of oxaliplatin and irinotecan has a modest antitumor activity with manageable toxicity as first-line treatment in metastatic cancer of the biliary tract and therefore it cannot be recommended as front-line treatment for unresectable biliary tract cancer.

Non-platinum-based first-line followed by platinum-based second-line chemotherapy or the reverse sequence in patients with advanced non-small cell lung cancer: a retrospective analysis by the lung cancer group of the Hellenic Oncology Research Group.

BACKGROUND: Non-platinum-containing regimens have been proposed as alternatives to platinum-based doublets in the first-line treatment of patients with non-small cell lung cancer (NSCLC). However, conflicting results about their equivalence have been reported. METHODS: We reviewed the records of patients enrolled in randomized controlled first-line trials conducted by the Hellenic Oncology Research Group from February 1997 to September 2006. The outcome of patients treated with first-line non-platinum-based chemotherapy who received platinum-based chemotherapy upon progression (cohort A) or platinum-based first-line chemotherapy followed by non-platinum-containing second-line chemotherapy (cohort B) was retrospectively analyzed. RESULTS: Two-hundred and sixty-seven patients were identified in cohort A, and 123 in cohort B. Median follow-up time was 12.5 and 15.7 months for cohorts A and B. A significantly higher response rate and time to tumor progression (TTP) was recorded for patients treated with platinum-based compared to those receiving non-platinum-based first-line chemotherapy (45.5 vs. 21.3%, p < 0.0001 and 5.8 vs. 3.1 months, p= 0.002, respectively). Platinum-based regimens administered as second-line treatment resulted in a 13.1% response rate. TTP for second-line chemotherapy did not differ significantly between the two cohorts. Median overall survival was 13.3 and 15.7 months for cohorts A and B (p = 0.538). CONCLUSION: Both sequences resulted in similar efficacy in terms of overall survival. Encouraging median survival was achieved for selected patients with NSCLC who received both first- and second-line chemotherapy.

Differential sensitivity of male germ cells to mainstream and sidestream tobacco smoke in the mouse.

Cigarette smoking in men has been associated with increased chromosomal abnormalities in sperm and with increased risks for spontaneous abortions, birth defects and neonatal death. Little is known, however, about the reproductive consequences of paternal exposure to second-hand smoke. We used a mouse model to investigate the effects of paternal exposure to sidestream (SS) smoke, the main constituent of second-hand smoke, on the genetic integrity and function of sperm, and to determine whether male germ cells were equally sensitive to mainstream (MS) and SS smoke. A series of sperm DNA quality and reproductive endpoints were investigated after exposing male mice for two weeks to MS or SS smoke. Our results indicated that: (i) only SS smoke significantly affected sperm motility; (ii) only MS smoke induced DNA strand breaks in sperm; (iii) both MS and SS smoke increased sperm chromatin structure abnormalities; and (iv) MS smoke affected both fertilization and the rate of early embryonic development, while SS smoke affected fertilization only. These results show that MS and SS smoke have differential effects on the genetic integrity and function of sperm and provide further evidence that male exposure to second-hand smoke, as well as direct cigarette smoke, may diminish a couple's chance for a successful pregnancy and the birth of a healthy baby.

Evaluation of DNA ploidy in relation with established prognostic factors in patients with locally advanced (unresectable) or metastatic pancreatic adenocarcinoma: a retrospective analysis.

BACKGROUND: Most patients with ductal pancreatic adenocarcinoma are diagnosed with locally advanced (unresectable) or metastatic disease. The aim of this study was to evaluate the prognostic significance of DNA ploidy in relation with established clinical and laboratory variables in such patients. METHODS: Two hundred and twenty six patients were studied retrospectively. Twenty two potential prognostic variables (demographics, clinical parameters, biochemical markers, treatment modality) were examined. RESULTS: Mean survival time was 38.41 weeks (95% c.i.: 33.17-43.65), median survival 27.00 weeks (95% c.i.: 23.18-30.82). On multivariate analysis, 10 factors had an independent effect on survival: performance status, local extension of tumor, distant metastases, ploidy score, anemia under epoetin therapy, weight loss, pain, steatorrhoea, CEA, and palliative surgery and chemotherapy. Patients managed with palliative surgery and chemotherapy had 6.7 times lower probability of death in comparison with patients without any treatment. Patients with ploidy score > 3.6 had 5.0 times higher probability of death in comparison with patients with ploidy score < 2.2 and these with ploidy score 2.2-3.6 had 6.3 times higher probability of death in comparison with patients with ploidy score < 2.2. CONCLUSION: According to the significance of the examined factor, survival was improved mainly by the combination of surgery and chemotherapy, and the presence of low DNA ploidy score.

Ascitic fluid cytology of yolk sac tumor of the ovary: a case report.

BACKGROUND: Yolk sac tumor (YST) of the ovary is a rare neoplasm typically affecting children and young women. We describe the cytomorphology of this tumor in ascitic fluid and discuss its differential diagnosis from other neoplasms. CASE: Smear preparations of the ascitic fluid showed a predominance of clusters of malignant cells with vacuolated cytoplasm, mimicking a mucinous adenocarcinoma, and fewer syncytial-like and glandular structures. Hyaline globules were extremely rare. Immunocytochemistry was positive for alpha-fetoprotein. CONCLUSION: The diagnosis of YST in ascitic fluid specimens may be challenging and requires the use of immunocytochemistry and the correlation of cytology with the remaining clinical and laboratory data.

Combination of weekly topotecan and gemcitabine as a salvage treatment in patients with recurrent ovarian cancer: a phase I study.

BACKGROUND: Evaluation of safety of the weekly intravenous gemcitabine/topotecan combination as salvage treatment in patients with recurrent epithelial ovarian cancer. METHODS: Twenty-four women with histologically-proven relapsed ovarian cancer (ROC) were enrolled in the study. Topotecan (1.75 mg/m2 IV) along with escalated doses of gemcitabine (starting dose 700 mg/m2 with increments of 100 mg/m2) were administered on days 1, 8, and 15 every 28 days. The maximum tolerated dose (MTD) and the dose-limiting toxicity of the combination were evaluated at the first cycle. RESULTS: Twenty-four ROC patients were enrolled in six dose-levels. Most patients had high-grade serous metastatic ovarian cancer (41.7%) and performance status score of 0-1 (95.8%). For 12 patients (50%) treatment was 2nd line and for 12 >2nd line. Eighty-eight cycles were administered with a median of three cycles per patient. The MTD was not reached and grade 3-4 (3.4% and 2.3% of cycles, respectively) neutropenia and grade 4 (3.4% of cycles) thrombocytopenia were the main adverse events. There was no case of febrile neutropenia. Non-hematologic toxicity was mild with grade 2 fatigue being the most frequent complain. The recommended MTD doses of the combination were topotecan 1.75 mg/m2 and gemcitabine 1200 mg/m2 on days 1, 8, and 15 every 28 days. Two complete (8.3%) and three (12.5%) partial responses were achieved (ORR: 20.8%). CONCLUSIONS: The weekly administration of gemcitabine/topotecan regimen in patients with pretreated metastatic ovarian cancer is an active chemotherapy combination, even in heavily pretreated patients, with a manageable toxicity profile which merits further investigation.

Metabolic Reprogramming in Astrocytes Distinguishes Region-Specific Neuronal Susceptibility in Huntington Mice.

The basis for region-specific neuronal toxicity in Huntington disease is unknown. Here, we show that region-specific neuronal vulnerability is a substrate-driven response in astrocytes. Glucose is low in HdhQ(150/150) animals, and astrocytes in each brain region adapt by metabolically reprogramming their mitochondria to use endogenous, non-glycolytic metabolites as an alternative fuel. Each region is characterized by distinct metabolic pools, and astrocytes adapt accordingly. The vulnerable striatum is enriched in fatty acids, and mitochondria reprogram by oxidizing them as an energy source but at the cost of escalating reactive oxygen species (ROS)-induced damage. The cerebellum is replete with amino acids, which are precursors for glucose regeneration through the pentose phosphate shunt or gluconeogenesis pathways. ROS is not elevated, and this region sustains little damage. While mhtt expression imposes disease stress throughout the brain, sensitivity or resistance arises from an adaptive stress response, which is inherently region specific. Metabolic reprogramming may have relevance to other diseases.