Expression of Hedgehog ligand and signal transduction components in mutually distinct isocitrate dehydrogenase mutant glioma cells supports a role for paracrine signaling

DNA methylation plays an important role in cancer biology and methylation events are important prognostic and predictive markers in many tumor types. We have used methylation-specific multiplex ligation-dependent probe amplification to survey the methylation status of MGMT and 25 tumor suppressor genes in 73 glioblastoma cases. The data obtained was correlated with overall survival and response to treatment. The study revealed that methylation of promoter regions in TP73 (seven patients), THBS1 (eight patients) and PYCARD (nine patients) was associated with improved outcome, whereas GATA5 (21 patients) and WT1 (24 patients) promoter methylation were associated with poor outcome. In patients treated with temozolomide and radiation MGMT and PYCARD promoter methylation events remained associated with improved survival whereas GATA5 was associated with a poor outcome. The identification of GATA5 promoter methylation in glioblastoma has not previously been reported. Furthermore, a cumulative methylation score separated patients into survival groups better than any single methylation event. In conclusion, we have identified specific methylation events associated with patient outcome and treatment response in glioblastoma, and these may be of functional and predictive/prognostic significance. This study therefore provides novel candidates and approaches for future prospective validation.     

Mathematical models of electrical activity of the pancreatic β-cell: A physiological review

Mathematical modeling of the electrical activity of the pancreatic β-cell has been extremely important for understanding the cellular mechanisms involved in glucose-stimulated insulin secretion. Several models have been proposed over the last 30 y, growing in complexity as experimental evidence of the cellular mechanisms involved has become available. Almost all the models have been developed based on experimental data from rodents. However, given the many important differences between species, models of human β-cells have recently been developed. This review summarizes how modeling of β-cells has evolved, highlighting the proposed physiological mechanisms underlying β-cell electrical activity.     

The Role of the Template in Prosthetically Guided Implantology

In prosthetically guided implantology, where ideal placement of implants is determined by the definitive restoration, the use of a radiographic/surgical template plays an essential role. This article describes how to fabricate a radiographic/surgical template to be used for radiographic diagnosis of the selected implant sites and as a guide during surgery for the insertion of the implant with correct angulation.     

Androgenetic alopecia and insulin resistance in young men

Background  Epidemiological studies have associated androgenetic alopecia (AGA) with severe young-age coronary artery disease and hypertension, and linked it to insulin resistance. We carried out a case–control study in age- and weight-matched young males to study the link between AGA and insulin resistance using the homeostasis model assessment of insulin resistance (HOMA-IR) index or metabolic syndrome clinical manifestations.
Methods  Eighty young males, 18–35 years old, with AGA ≥ stage III in the Hamilton–Norwood classification, and 80 weight- and age-matched controls were included. Alopecia, glucose, serum insulin, HOMA-IR index, lipid profile and androgen levels, as well as metabolic syndrome criteria, were evaluated.
Results  The HOMA-IR index was significantly higher in cases than controls. Nonobese cases had a higher mean diastolic blood pressure and a more frequent family history of AGA than nonobese controls. A borderline difference in the HOMA-IR index was found in obese AGA cases vs. obese controls [ P =  0·055, 95% confidence interval (CI) 2·36–4·20 vs. 1·75–2·73]. Free testosterone values were significantly higher in controls than cases, regardless of body mass index (BMI). A statistically significant additive effect for obesity plus alopecia was found, with significant trends for insulin, the HOMA-IR index, lipids and free testosterone when BMI and alopecia status were used to classify the participants.
Conclusions  Our results support the recommendation for assessing insulin resistance and cardiovascular-related features and disorders in all young males with stage III or higher AGA, according to the Hamilton–Norwood classification.     

A hydrodynamic study of pleural drainage systems: some practical consequences

BACKGROUND: A pleural drainage system must be capable of efficiently evacuating the air or fluids from the pleural cavity so that adequate lung reexpansion can take place. The air flow and negative pressure of the system will depend on the particular design of each model. This experimental study analyzes the specifications and performance of the pleural drainage systems currently on the market. METHODS: Thirteen models of pleural drainage systems connected to wall suction were examined. The models were classified into the following three groups: dry systems; wet systems; and single-chamber systems. We determined the ambient air flow and the negative pressure generated according to the suction level. The components of each model are also described. RESULTS: Under normal conditions, dry (except for the Sentinel Seal; Sherwood Medical; Tullamore, Ireland), wet, and single-chamber systems reach similar air flow rates (17 to 30, 24 to 27, and 22 to 28 L/min, respectively). With higher wall suction levels, wet systems increase the air flow (26 to 49 L/min) but the negative pressure becomes unstable because of the water loss phenomenon, dry systems increase the air flow (29 to 50 L/min) without modifying the regulator pressure, and single-chamber systems also raise the air flow (45 to 51 L/min) but increase the negative pressure. When there is an air leak, dry systems (except for the Sentinel Seal) lose less negative pressure than the other systems. CONCLUSIONS: The functioning of these systems can be optimized only by applying a suitable wall suction level adjusted to each case. Although the three types of systems are capable of evacuating adequate air flow rates, the negative pressure and the capacity to maintain it in the presence of an air leak are different in each system. Being fitted with valves and not water compartments makes the dry systems the safest and the ideal for use when the patient has to be moved.     

Adult bone marrow-derived stem cells use R-cadherin to target sites of neovascularization in the developing retina.

Adult bone marrow contains a population of hematopoietic stem cells (HSCs) that can give rise to cells capable of targeting sites of neovascularization in the peripheral or retinal vasculature. However, relatively little is known about the mechanism of targeting of these cells to sites of neovascularization. We have analyzed subpopulations of HSCs for the expression of a variety of cell surface adhesion molecules and found that R-cadherin, a calcium-dependent cell-cell adhesion molecule important for normal retinal endothelial cell guidance, was preferentially expressed by functionally targeting HSCs. Preincubation of HSCs with function-blocking anti-R-cadherin antibodies or novel R-cadherin-specific peptide antagonists effectively prevented targeting of bone marrow-derived cells to the developing retinal vasculature in vivo. Whereas control-injected HSCs targeted to all 3 normal developing retinal vascular layers, blocking R-cadherin-mediated adhesion resulted in mistargeting of the HSCs to the normally avascular outer retina. Our results suggest that vascular targeting of bone marrow-derived HSCs is dependent on mechanisms similar to those used by endogenous retinal vascular endothelial cells. Thus, R-cadherin antagonists may be useful in the treatment of neovascular diseases in which circulating HSCs contribute to abnormal angiogenesis.     

A case report of a pyogenic liver abscess caused by Fusobacterium nucleatum in a patient with autosomal dominant polycystic kidney disease undergoing hemodialysis

Pyogenic liver abscess (PLA) is a process with significant morbidity and mortality and is a rare complication in an aisled way in patients with autosomal dominant polycystic kidney disease (ADPKD). In addition to hepatic cyst infection, intracystic hemorrhage is another complication seen in ADPKD patients; however, the liver parenchyma itself remains normal. A PLA located in normal liver tissue in these kinds of patients has not been previously reported. Fusobacterium nucleatum is an anaerobic bacterium with rare involvement other than in periodontal infections. A 58-year-old Caucasian male, who was on hemodialysis treatment from July 2004 due to end-stage renal disease secondary to ADPKD, was admitted with fever, rigor, chills, weakness, and abdominal pain of 10 days duration. During that time, ciprofloxacin 500 mg, twice daily, gentamycin 80 mg/48 h, and vancomycin 1 g/week, were prescribed, but treatment was interrupted by hospitalization. Physical examination on admission revealed that the patient had a fever of 39.8 degrees C, pallor, chills, right upper quadrant abdominal pain, and hepatosplenomegaly. Abdominal ultrasound revealed a 5.3 cm diameter collection with irregular configuration located in the caudate lobe. Abdominal computed tomography (CT) showed a large multiloculated hepatic collection. The PLA was managed with antibiotics (metronidazole) and continuous catheter drainage (8Fr drainage catheters [Abocath-T, Abbott, Sligo, Ireland]) into the abscess. Fluid culture was positive for F. nucleatum. Complete remission was obtained after 12 days without complications. We describe a PLA by F. nucleatum, in a very rare location in an ADPKD patient undergoing hemodialysis without complicated cysts, managed with antibiotics and percutaneous drainage with satisfactory resolution.     

Glucose-6-phosphate dehydrogenase (G-6-PD) mutations in Mexico: four new G-6-PD variants

Screening for mutations at the G-6-PD gene by PCR-SSCP combined with restriction enzyme analysis and DNA sequencing was performed in nine G-6-PD deficient individuals with negative results for the presence of the most frequent G-6-PD mutations previously observed in Mexican population. The variants G-6-PD Valladolid(406T), G-6-PD Durham(713G), and G-6-PD Viangchan(871A) and four new G-6-PD mutant alleles were identified. The new mutations are located at cDNA nt 376 A --> T (126 Asn --> Tyr), nt 770 G --> T (257 Arg --> Leu), nt 1094 G --> A (365 Arg --> His), and nt 1285 A --> G (429 Lys --> Glu) and they were named G-6-PD San Luis Potosi, G-6-PD Zacatecas, G-6-PD Veracruz, and G-6-PD Yucatán, respectively. To date, a total of 18 different G-6-PD variants have been observed in Mexico and several of them are common in Africa, South Europe, and Southeast Asia.