Microvascular injection studies in rubeosis iridis and neovascular glaucoma

Microvascular silicone injection, tissue clearing, and histologic examination were used to demonstrate the origin, distribution, and interconnections of newly formed iris and chamber angle blood vessels in four eyes with rubeosis iridis and neovascular glaucoma associated with diabetic retinopathy and central retinal vessel occlusion. The newly formed iris vessels that formed either a tight, evenly distributed (diabetic) or loose, irregularly distributed (central vessel occlusion) network in the iris originated from the normal iris arteries that were branches of either the major arterial circle or of the perforating branches of the anterior ciliary arteries, and drained into the normal iris and ciliary body veins and occasionally into the paralimbal episcleral veins. These newly formed iris vessels appeared to shunt intravascular fluid from arteries to veins. The newly formed anterior chamber angle vessels that formed tufts and arcades at the trabecular meshwork also originated from the roots of the iris arteries and the ciliary body arteries and connected with the peripheral neovascular iris network. In addition, the circumferentially running angle vessels that coursed within the trabecular meshwork branched into and coursed within a fibrosed Schlemm's canal and into two of its intrascleral collector channels. No open communication between these newly formed vessels and the Schlemm's canal-aqueous outflow system was seen.     

Antoine Marfan and his syndrome: one hundred years later

A high-performance liquid chromatographic (HPLC) method is presented for the simultaneous detection of ubiquinone-9 and 10 in rat tissues such as blood, myocardium, and muscle. After liquid-liquid extraction, the ubiquinones are subsequently analyzed by HPLC with ultraviolet (UV) detection at their maximum absorbance (275 nm). Reference calibration curves in ethanol are used to determine tissular levels of ubiquinones. Because a treatment with HMG-CoA reductase inhibitors is expected to decrease the ubiquinone levels, reference calibration curves are performed to ensure that the ratios (ubiquinone/internal standard) observed in such an experiment could be evaluated directly on a calibration curve. The assay is sensitive (0.0625 microgram/mL), reproducible (4% coefficient of variation for ubiquinone-9 and 6% for ubiquinone-10), and linear up to 20 micrograms/mL (or 100 mg of tissue) for ubiquinone-9 and up to 10 micrograms/mL (or 100 mg of tissue) for ubiquinone-10. The ubiquinone levels in control tissues or blood are within the ranges of those previously reported.     

Virulence of enterohemorrhagic Escherichia coli: role of molecular crosstalk

Many bacterial exotoxins, originally defined by cytopathic effects, may also possess additional biological activities. The capacity of exotoxins to elicit the synthesis and secretion of pro- or anti-inflammatory cytokines may be as important as their direct toxic effects in pathogenesis. One example of such 'molecular crosstalk' occurs between Shiga toxins and the cytokines made in response to these toxins during the development of disease.     

Severe pyruvate kinase deficiency anemia. A case report

BACKGROUND: Pyruvate kinase deficiency is a rare cause of hemolytic anemia and, in its most severe form, requires splenectomy in childhood. During pregnancy, severe cases have been traditionally managed with prophylactic blood transfusions to keep the hemoglobin concentration above arbitrary thresholds of 7-8 g/dL. CASE: A case of severe pyruvate kinase deficiency anemia was managed conservatively without blood transfusions even though the hemoglobin concentration reached a nadir of 6.8 g/dL. The perinatal outcome was good. CONCLUSION: In cases of severe pyruvate kinase deficiency anemia, pregnancy per se might not be an indication for prophylactic blood transfusions.     

Obfuscation of allosteric structure-function relationships by enthalpy-entropy compensation

The pH and temperature dependence of the allosteric properties of phosphofructokinase (PFK) from Bacillus stearothermophilus have been studied from 5 to 9 and 6 to 40 degrees C, respectively. Throughout this pH and temperature range the allosteric ligands MgADP and phospho(enol)pyruvate (PEP) have no effect on kcat. The dissociation constants of the substrate, fructose 6-phosphate, and the allosteric ligands, as well as the absolute value of the coupling free energies between these ligands, all increase when the pH is raised, indicating that the inhibition by PEP and the activation by MgADP increase despite each ligand's somewhat lower affinity. However, the constituent coupling enthalpies and entropies substantially diminish in absolute value as pH is increased, suggesting that the magnitudes of molecular perturbations engendered by the binding of allosteric ligands do not correlate with the magnitudes of the functional consequences of those perturbations. Temperature and pH exert their influence on the observed allosteric behavior by changing the relative contributions made by the largely compensating DeltaH and TDeltaS terms to the coupling free energy.     

Carcinoma of the stomach following the Chernobyl nuclear accident

Medical consequences of many nuclear accidents on humans are well studied, but the results pertaining to gastric cancer patients who were exposed to radiation as a result of the Chernobyl nuclear accident have not been analysed. In this study, the outcome of the surgical treatment of 68 gastric cancer patients who were exposed to radiation as a result of the Chernobyl nuclear accident was compared with that of 117 consecutive gastric cancer patients from uncontaminated areas of the Ukraine. Patients in the study group was significantly younger than that of the control group. Comparative analysis showed the same frequency of regional metastases (65.7% versus 71.1%, P > 0.05), but a smaller number of distant metastases (23.8% versus 38.1%, P < 0.05) in the study group. 41.2% of patients in the study group underwent total gastrectomy compared to 19.6% of patients in the control group (P = 0.002). Postoperative complications developed in 13.2% of patients in the study group, while postoperative mortality in the study group was 7.3% compared to 1.7% in the control group. A significant decrease in CD16 cells was noted in patients from the study group following the operative procedure. Young age, invasive tumours with smaller number of distant metastases, frequent necessity for total gastrectomy and combined operations with adjacent organs, a higher level of postoperative morbidity and mortality and low levels of natural killer cells (CD16+) with a tendency to decrease after surgery are characteristic of patients with carcinoma of the stomach affected by the Chernobyl accident.