Perinatal development of circadian melatonin production in domestic chicks

In contrast to the situation in mammals, in which circadian melatonin production by the pineal gland does not begin until some time after birth, the development of pineal gland rhythmicity is an embryonic event in the precocial domestic fowl. A distinct melatonin rhythm was found in 19-d-old chick embryos maintained under light:dark (LD) 16:8. No significant variation in melatonin levels was detected in embryos exposed to LD 8:16. The melatonin rhythm in the pineal gland and plasma of chick embryos incubated for 18 d in LD 12:12 persisted for 2 d in constant darkness indicating that melatonin production is under circadian control at least from the end of embryonic life. A 1-d exposure to a LD cycle during the first postembryonic day was sufficient to entrain the melatonin rhythm, and previous embryonic exposure to either LD or constant darkness (DD) neither modified this rapid synchronization nor did it affect the melatonin pattern during the two subsequent days in DD. It is suggested that, in contrast to the situation in mammals, the avian embryo has evolved its own early circadian melatonin-producing system because, as a consequence of its extrauterine development, it cannot use the system of its mother.     

Ultrastructural Changes of Mitochondria in the Cultivated Skin Fibroblasts of Patients with Point Mutations in Mitochondrial DNA

Mitochondrial disorders represent a heterogeneous group of multisystem diseases with extreme variability in clinical phenotype. The diagnosis of mitochondrial disorders relies heavily on extensive biochemical and molecular analyses combined with morphological studies including electron microscopy. Although muscle is the tissue of choice for electron microscopic studies, the authors investigated cultivated human skin fibroblasts (HSF) harboring 3 different pathologic mtDNA mutations: 3243A > G, 8344A > G, 8993T > G. They addressed to the possibility of whether mtDNA mutations influence mitochondrial morphology in HSF and if ultrastructural changes of mitochondria may be used for differential diagnostics of mitochondrial disorders caused by mtDNA mutations. Ultrastructural analysis of patients' HSF revealed a heterogeneous mixture of mainly abnormal, partially swelling mitochondria with unusual and sparse cristae. The most characteristic cristal abnormalities were heterogeneity in size and shapes or their absence. Typical filamentous and branched mitochondria with numerous cristae as appeared in control HSF were almost not observed. In all lines of cultured HSF with various mtDNA mutations, similar ultrastructural abnormalities and severely changed mitochondrial interior were found, although no alterations in function and amount of OXPHOS were detected by routinely used biochemical methods in two lines of cultured HSF. This highlights the importance of morphological analysis, even in cultured fibroblasts, in diagnostics of mitochondrial disorders.     

White matter alteration and cerebellar atrophy are hallmarks of brain MRI in alpha-mannosidosis

ObjectiveDespite profound neurological symptomatology there are only few MRI studies focused on the brain abnormalities in alpha-mannosidosis (AM). Our aim was to characterize brain MRI findings in a large cohort of AM patients along with clinical manifestations.MethodsTwenty-two brain MRIs acquired in 13 untreated AM patients (8 M/5F; median age 17 years) were independently assessed by three experienced readers and compared to 16 controls.ResultsFocal and/or diffuse hyperintense signals in the cerebral white matter were present in most (85%) patients. Cerebellar atrophy was common (62%), present from the age of 5 years. Progression was observed in two out of 6 patients with follow-up scans. Cortical atrophy (62%) and corpus callosum thinning (23%) were already present in a 13-month-old child. The presence of low T₂ signal intensity in basal ganglia and thalami was excluded by the normalized signal intensity profiling. The enlargement of perivascular spaces in white matter (38%), widening of perioptic CSF spaces (62%), and enlargement of cisterna magna (85%) were also observed. Diploic space thickening (100%), mucosal thickening (69%) and sinus hypoplasia (54%) were the most frequent non-CNS abnormalities.ConclusionWhite matter changes and cerebellar atrophy are proposed to be the characteristic brain MRI features of AM. The previously reported decreased T₂ signal intensity in basal ganglia and thalami was not detected in this quantitative study. Rather, this relative MR appearance seems to be related to the diffuse high T₂ signal in the adjacent white matter and not the gray matter iron deposition that has been hypothesized.     

Adverse effects of irreversible electroporation of malignant liver tumors under CT fluoroscopic guidance: a single-center experience

PURPOSE

We aimed to describe the frequency of adverse events after computed tomography (CT) fluoroscopy-guided irreversible electroporation (IRE) of malignant hepatic tumors and their risk factors.

METHODS

We retrospectively analyzed 85 IRE ablation procedures of 114 malignant liver tumors (52 primary and 62 secondary) not suitable for resection or thermal ablation in 56 patients (42 men and 14 women; median age, 61 years) with regard to mortality and treatment-related complications. Complications were evaluated according to the standardized grading system of the Society of Interventional Radiology. Factors influencing the occurrence of major and minor complications were investigated.

RESULTS

No IRE-related death occurred. Major complications occurred in 7.1% of IRE procedures (6/85), while minor complications occurred in 18.8% (16/85). The most frequent major complication was postablative abscess (4.7%, 4/85) which affected patients with bilioenteric anastomosis significantly more often than patients without this condition (43% vs. 1.3%, P = 0.010). Bilioenteric anastomosis was additionally identified as a risk factor for major complications in general (P = 0.002). Minor complications mainly consisted of hemorrhage and portal vein branch thrombosis.

CONCLUSION

The current study suggests that CT fluoroscopy-guided IRE ablation of malignant liver tumors may be a relatively low-risk procedure. However, patients with bilioenteric anastomosis seem to have an increased risk of postablative abscess formation.About 70% of hepatic metastases are nonresectable because of their anatomic location, the presence of comorbidities, or limited hepatic functional reserve (1). In these patients and in case of nonresectable primary liver tumors, percutaneous thermal ablation procedures, such as radiofrequency (RF) and microwave ablation, have become effective tools for treating hepatic malignancies (2–4). However, the effectiveness of RF and microwave treatment may be limited, either because of thermal damage to temperature-sensitive structures located in close proximity to the target tissue (5) or because of incomplete ablation of tumors adjacent to major hepatic vessels due to a phenomenon commonly termed “heat-sink effect” (6–10) which describes the loss of the applied thermal energy through the blood flow in those major vessels, whereby the effective energy application remains inadequate to ablate the target lesion.Irreversible electroporation (IRE) is a theoretically nonthermal ablation technique that delivers a series of high-voltage millisecond electrical pulses to the surrounding tissue, thus leading to irreversible disruption of the integrity of cell membranes and subsequent cell death by apoptosis (11–14). IRE may overcome the problems raised with thermal ablation: previous animal studies reported that bile ducts, blood vessels, nerves, and connective tissues are affected by IRE; however, regeneration is possible to some extent due to preservation of the tissue architecture (12, 13, 15–19). Moreover the feasibility of inducing cell death up to a vessel wall without any perivascular sparing was shown with IRE (12, 13, 18). The safety of IRE in the treatment of humans has been described (20). First reports have described potential complications after IRE, such as hemorrhage requiring blood transfusion (1.2%, two of 167 ablation procedures), portal vein thrombosis (3.2%, one of 31 ablation procedures), injury to bile ducts (1.8%, three of 167 ablation procedures), and infection (3.6%, six of 167 ablation procedures) (21, 22). However, few data are available for evaluating the potential risk factors associated with the occurrence of post-IRE complications.The purpose of this study was to review the frequency of mortality and morbidity after computed tomography (CT) fluoroscopy-guided liver IRE conducted at a single center and assess the factors influencing the occurrence of major complications.     

Chemoprevention of colorectal cancer with nonsteroidal anti‐inflammatory drugs

Colorectal carcinoma is one of the commonest solid organ tumors in the world and its prevalence appears to be increasing in Asia. Recently, there has been much interest in various chemotherapeutic agents for the management of this condition, in particular nonsteroidal anti‐inflammatory drugs (NSAIDs). There is a large amount of data that suggest traditional NSAIDs, as well as the new cyclooxygenase (COX)‐2 selective inhibitors such as rofecoxib and celecoxib, have a role in the setting of primary and secondary prevention, and adjuvant therapy of both sporadic colorectal carcinoma and familial adenomatous polyposis. This review examines some of this data, as well as the potential problems and limitations of using these agents, particularly in light of the recent withdrawal of rofecoxib.     

DNA replication stress underlies renal phenotypes in CEP290-associated Joubert syndrome

Juvenile ciliopathy syndromes that are associated with renal cysts and premature renal failure are commonly the result of mutations in the gene encoding centrosomal protein CEP290. In addition to centrosomes and the transition zone at the base of the primary cilium, CEP290 also localizes to the nucleus; however, the nuclear function of CEP290 is unknown. Here, we demonstrate that reduction of cellular CEP290 in primary human and mouse kidney cells as well as in zebrafish embryos leads to enhanced DNA damage signaling and accumulation of DNA breaks ex vivo and in vivo. Compared with those from WT mice, primary kidney cells from Cep290-deficient mice exhibited supernumerary centrioles, decreased replication fork velocity, fork asymmetry, and increased levels of cyclin-dependent kinases (CDKs). Treatment of Cep290-deficient cells with CDK inhibitors rescued DNA damage and centriole number. Moreover, the loss of primary cilia that results from CEP290 dysfunction was rescued in 3D cell culture spheroids of primary murine kidney cells after exposure to CDK inhibitors. Together, our results provide a link between CEP290 and DNA replication stress and suggest CDK inhibition as a potential treatment strategy for a wide range of ciliopathy syndromes.