Cancer gene therapy with tissue inhibitors of metalloproteinases (TIMPs)

Matrix metalloproteinases (MMPs) are of crucial importance for the invasive behavior of primary tumors and their metastases. MMP activity is regulated by the four naturally occurring tissue inhibitors of metalloproteinases (TIMPs). It has been shown that overexpression of TIMPs in tumors of various origins leads to reduced tumor growth and formation of metastases. More recently, antitumor efficacy by in vivo gene transfer of TIMPs has been reported in several clinically relevant animal models. This review analyses the therapeutic potential of the TIMPs from a cancer gene therapeutic point of view with particular emphasis on cell culture and in vivo data.     

Expression pattern of Popdc2 during mouse embryogenesis and in the adult.

The Popdc2 gene is a member of the Popeye domain containing gene family encoding membrane proteins with prominent expression in striated and smooth muscle tissue. After introducing a LacZ reporter gene into the Popdc2 locus, expression was studied during embryonic development and postnatal life. At embryonic day (E) 7.5, expression was present in cardiac and extraembryonic mesoderm. At E10.5, expression was found in heart, somites, and mesothelial cells lining the coelom. At E12.5, expression was present in the coelomic mesothelium, pericardial and myocardial layer of the heart, skeletal muscle, bladder, gut, and umbilical vessels. Postnatal expression was found in cardiac and skeletal muscle and in the smooth muscle layer of colon, rectum, and bladder. In the stomach, Popdc2 was exclusively present in the pyloric epithelium. In conclusion, Popdc2 is expressed in various muscle and nonmuscle cell types during embryonic development and in postnatal life.     

Investigating Population Risk Factors of Pancreatic Cancer by Evaluation of Optical Markers in the Duodenal Mucosa

Pancreatic cancer screening has been hampered by the high rate of complications associated with interrogating the pancreas. The closest non-invasively accessible mucosa available for pancreatic cancer screening is the periampullary duodenal tissue. Our earlier report has shown the potential of using optical markers to interrogate this tissue for the presence of pancreatic cancer. In this study, we report a larger data set of low-coherence enhanced backscattering (LEBS) and elastic light scattering fingerprinting (ELF) optical markers from the periampullary duodenal mucosa. Optical measurements from biopsy samples were acquired from a total of 203 patients with varying clinical classification including healthy controls, a family history of pancreatic cancer, pancreatitis, mucinous cystic precursor lesions, pancreatic cancer, and other pancreatic malignancies. Evaluation of the performance of an independent testing set for discriminating healthy control patients from pancreatic cancer patients showed a 95% sensitivity, 71% specificity, and 85% area under the receiver operator characteristic (AUROC) curve. Importantly, this performance was uncompromised for detecting potentially curable stages of the disease. Additionally, optical markers in higher risk populations such as family history and pancreatitis had values between those of healthy control and pancreatic cancer patients, thus allowing for future investigations of screening from these high risk groups.     

Retrospective evidence that the MHC (B haplotype) of chickens influences genetic resistance to attenuated infectious bronchitis vaccine strains in chickens.

Infectious bronchitis is a respiratory disease of chickens that is caused by the coronavirus infectious bronchitis virus (IBV). Virtually all broiler and layer breeder flocks are routinely vaccinated against IBV. Two hatches of 1-day-old chicks from four lines were mistakenly vaccinated for infectious bronchitis using a moderately attenuated vaccine designed for chicks of an older age. The vaccination resulted in high mortality, and chicks from three of four lines died with signs typical of infectious bronchitis. The mortality that occurred using this less-attenuated vaccine was significantly influenced by the genetic line, and the MHC (B) haplotype in chickens of three B congenic lines. B congenic chickens possessing the B*15 haplotype were resistant in contrast to chickens possessing the B*13 or B*21 haplotypes. Chicks from two further hatches of the four lines were vaccinated appropriately with a more attenuated IBV vaccine, and only limited chick mortality was seen. These retrospective data from two repeated hatches confirm earlier data indicating chicken genes influence resistance to IBV, and indicate for the first time that genes tightly linked to the B haplotype are relevant in resistance to IBV. Due to extenuating circumstances it was not possible to verify results with chicks from F2 matings. Factors that may enhance definition of the role of the B haplotype in immune response to IBV, and the desirability for further analysis of a B haplotype-linked influence on immunity to IBV are discussed.     

Transduction mechanisms for the taste of amino acids.

Amino acids are important taste stimuli for a variety of animals. One animal model, the channel catfish, I. punctatus, possesses sensitive taste receptor systems for several amino acids. Neurophysiological and biochemical receptor binding studies suggest the presence of at least three receptor pathways: one is a relatively nonspecific site(s) responsive to short-chain neutral amino acids such as L-alanine (L-ALA); another is responsive to the basic amino acid L-arginine (L-ARG); still another is a low affinity site for L-proline (L-PRO). Several possible transduction pathways are available in the taste system of this animal model for these amino acids. One of these, formation of inositol trisphosphate (IP3) and cyclic AMP (cAMP), is mediated by GTP-binding regulatory proteins, while another involves ion channels directly activated by stimuli. L-ALA is a potent stimulus to cAMP and IP3 accumulation, while L-ARG at low concentrations is without effect. On the other hand, L-ARG and L-PRO, but not L-ALA, are able to activate stimulus-specific and cation-selective channels in taste epithelial membranes reconstituted in phospholipid bilayers at the tips of patch pipettes. Preliminary studies using mouse taste tissue demonstrate that monosodium-L-glutamate (MSG) did not enhance production of IP3 or cAMP. However, in reconstitution experiments using taste epithelium of mouse, conductance changes due to MSG are observed. The specificity of this channel(s) and its uniqueness have yet to be determined.     

Leaf trajectory verification during dynamic intensity modulated radiotherapy using an amorphous silicon flat panel imager

An independent verification of the leaf trajectories during each treatment fraction improves the safety of IMRT delivery. In order to verify dynamic IMRT with an electronic portal imaging device (EPID), the EPID response should be accurate and fast such that the effect of motion blurring on the detected moving field edge position is limited. In the past, it was shown that the errors in the detected position of a moving field edge determined by a scanning liquid-filled ionization chamber (SLIC) EPID are negligible in clinical practice. Furthermore, a method for leaf trajectory verification during dynamic IMRT was successfully applied using such an EPID. EPIDs based on amorphous silicon (a-Si) arrays are now widely available. Such a-Si flat panel imagers (FPIs) produce portal images with superior image quality compared to other portal imaging systems, but they have not yet been used for leaf trajectory verification during dynamic IMRT. The aim of this study is to quantify the effect of motion distortion and motion blurring on the detection accuracy of a moving field edge for an Elekta iViewGT a-Si FPI and to investigate its applicability for the leaf trajectory verification during dynamic IMRT. We found that the detection error for a moving field edge to be smaller than 0.025 cm at a speed of 0.8 cm/s. Hence, the effect of motion blurring on the detection accuracy of a moving field edge is negligible in clinical practice. Furthermore, the a-Si FPI was successfully applied for the verification of dynamic IMRT. The verification method revealed a delay in the control system of the experimental DMLC that was also found using a SLIC EPID, resulting in leaf positional errors of 0.7 cm at a leaf speed of 0.8 cm/s.     

5-HT mechanisms of median raphe nucleus in the conditioned freezing caused by light/foot-shock association

We have shown that 5-HT mechanisms of the median raphe nucleus (MRN) are involved in contextual fear-conditioning processes as electrolytic or neurotoxic lesions with N-methyl-D-aspartate (NMDA) or injections of 8-hydroxy-2-(di-n-propilamino)-tetralin (8-OH-DPAT) into this structure inhibit freezing behavior in a contextual fear paradigm. In this work, we extend these studies by analyzing the behavioral responses in a classical fear-conditioning paradigm (light or tone/foot-shock association) in rats with either neurochemical lesion with NMDA or injected with 8-OH-DPAT into the MRN. The animals received NMDA or 8-OH-DPAT or saline microinjections into the MRN and were submitted to conditioning trials in an experimental chamber, where they received 10 foot-shocks (0.6 mA, 1 s, variable interval between 10 and 50 s) paired with tone or light (CS). On the next day, they were tested in a different experimental chamber, with or without CS presentation, where the duration of freezing and the number of rearing episodes were recorded. Light or tone alone caused a significant amount of freezing. NMDA lesions or 8-OH-DPAT injections into the MRN clearly inhibited freezing behavior in rats conditioned to light/foot-shock association, but not in the conditioning sessions with tones. Besides the proposed role in contextual fear conditioning, these results clearly show that MRN is involved in the fear conditioning with light as conditioned stimuli. Distinct neural substrates seem to subserve conditioning fear with acoustic stimuli.     

Hyperuricemia as a risk factor of coronary heart disease: The Framingham Study

Uric acid values were obtained on subjects of the original Framingham cohort at their fourth and 13th biennial examinations. The mean uric acid value for men was 5.0 mg/dl at the fourth examination and 5.7 mg/dl at examination 13 and was 3.9 mg/dl and 4.7 mg/dl, respectively, for women. This secular trend was due to both "laboratory drift" and increasing use of diuretics. Serum uric acid values were consistently higher in subjects of both sexes who were taking antihypertensive drugs at both examinations. Serum uric acid values correlated with systolic and diastolic blood pressure in both sexes; the relationship was stronger in women than in men and for systolic than for diastolic pressure. Correlations were stronger at examination 4 than at examination 13 when more antihypertensive treatment was used. Examination 4 serum uric acid predicted the subsequent development of coronary heart disease, in general, and myocardial infarction, in particular, but not angina pectoris. The uric acid relationship with myocardial infarction was equally strong in both sexes, even correcting for antihypertensive treatment. However, in multivariate analysis, including age, systolic blood pressure, relative weight, cigarette smoking, and serum cholesterol, serum uric acid did not add independently to the prediction of coronary heart disease.     

Values and limitations of transstenotic pressure gradients measured during percutaneous coronary angioplasty

The pressure gradient across coronary stenoses is measured routinely during angioplasty. Due to the finite size of the angioplasty catheter within the stenotic cross section, the remaining luminal area is further reduced and the transstenotic gradient may be overestimating the "true" pressure drop. This "true" pressure gradient can be approximated from the mean coronary blood flow and the stenosis geometry from theoretical models. Goal of this study was to assess the values and limitations of the in vivo measurements of the pressure gradient versus the calculated values. Therefore, flow in the great cardiac vein was measured in 13 patients before and/or after angioplasty of a proximal left anterior descending stenosis, not filled by collaterals. The Poiseuille and turbulent contributions to flow resistance were determined from stenosis geometry assessed by quantitative coronary angiography. A fourfold increase in the luminal area (from 0.7 mm2 pre- to 2.8 mm2 post angioplasty) was associated with a fourfold decrease in the in vivo measured transstenotic gradient (from 59 mm Hg pre- to 13 mm Hg post angioplasty). The occlusion area and the measured gradient were linearly correlated: gradient = 69-17 X occlusion area (r = 0.76). However, as expected, the transstenotic gradient systematically overestimated the theoretical gradient calculated from the laws of fluid dynamics. A nonlinear relation was found between the calculated gradient P and the occlusion area As: P = 15 X As-2 (r = 0.87).