Optimal techniques for arterial gene transfer

Cardiovascular gene therapy is becoming a clinical reality due to improved vectors, delivery systems and careful experimental validation studies. Nearly all cardiovascular diseases are amenable to gene therapy, but the optimal combination of vector, delivery system and therapeutic gene is likely to be unique to each application. Currently, the most efficient vectors available are replication-defective adenoviral vectors, but transgene expression is limited in time due to a strong immune response. Conversely, non-viral vectors or plasmid DNA may be used safely but have very limited efficiency. Percutaneous, catheter-based delivery is feasible for most applications. The ultimate issues that will decide of the future of gene therapy are safety of the transfer and delivery techniques as well as cost/effectiveness comparisons with alternative therapies, including local delivery of drugs, proteins and/or mechanical devices.     

Another false alarm? apnea monitor activation in a Neonatal Intensive Care Unit graduate

Neonatal emergencies have become more common as increasingly sophisticated Neonatal Intensive Care Units graduate lower birth-weight babies born at younger gestational ages. These patients present a number of challenges to emergency physicians. They are often discharged with apnea monitors, which generate a high number of false alarms. Neonatal Intensive Care Unit graduates, however, are predisposed to a number of conditions that can result in true episodes of apnea. We present such a case and will discuss the unusual underlying cause of apnea, the utility of apnea monitors, and the need for emergency physicians to be prepared to evaluate and treat these potentially complicated patients.     

Treatment of early T1 small T2N breast cancers. Our experience at the Yaounde General Hospital. 21 cases]

OBJECTIVE: To modify the classic fetal biophysical profile (FBP) with the aim of obtaining rapid and accurate information about actual fetal condition in non-compromised fetuses with a subsequent favorable outcome and to be suitable for a number of outclinic patients. METHODS: Four-hundred and ninety-four fetuses from singleton pregnancies in two randomized groups were monitored by the modified FBP (mFBP) and 168 of them after the external vibratory acoustic stimulation (VAS/mFBP). The mFBP was characterized by two main characteristics: non-stress test was excluded and the testing was finished at the moment when all of the three fetal biophysical activities became normal. The external VAS was applied only in cases with no evidence of fetal activity at the start of the FBP. RESULTS: Of the examined fetuses, 326 fetuses in the control group were monitored by the mFBP and there were 316 (96.9%) favorable outcomes and 10 (3.1%) adverse perinatal outcomes. The sensitivity, specificity and positive and negative predictive values of the mFBP score in predicting adverse perinatal outcome were 60, 99, 66.7 and 98.7%, respectively. In the study group of 168 fetuses there were 165 (98.2%) favorable outcomes and three (1.8%) adverse perinatal outcomes. The sensitivity, specificity and positive and negative predictive values of the VAS/mFBP were 66.7, 100, 100 and 99.4%, respectively. The efficiency of the VAS/mFBP in predicting perinatal mortality alone was even higher. After the external VAS and the first 5 min of the modified testing approximately two-fifths (41.8%) of healthy fetuses with a subsequent good outcome exhibited normal in all of the three biophysical activities and approximately two-thirds (65.5%) of them after 10 min. In the VAS/mFBP group of healthy fetuses, during the same time periods, normal breathing movements were observed in 72% and 87% of fetuses, respectively. CONCLUSIONS: According to our results the mFBP and particularly the VAS/mFBP antenatal protocol as a new and rational variant of the FBP could improve fetal assessment allowing in cases of non-compromised fetuses rapid and accurate information about actual fetal well-being. Because of its high accuracy and a reduced testing time the antepartal method with observation of fetal breathing movements after VAS is becoming acceptable as a screening of fetal well-being evaluation in outclinic conditions.     

Evolution of multiprotocol label switching

Multiprotocol label switching (MPLS) is rapidly emerging as an Internet Engineering Task Force (IETF) standard intended to enhance the speed, scalability, and service provisioning capabilities in the Internet. MPLS uses the technique of packet forwarding based on labels, to enable the implementation of a simpler high-performance packet forwarding engine. This also decouples packet forwarding from routing, facilitating the provision of varied routing services independent of the packet forwarding paradigm. The authors track the evolution of this technology in relation to other existing technologies. Then an overview of the MPLS architecture and design is provided. In addition, some of the work that was a precursor to MPLS is discussed, as well as related issues and debates     

Desensitization of mutant acetylcholine receptors in transgenic mice reduces the amplitude of neuromuscular synaptic currents

While the slow onset of desensitization of nicotinic acetylcholine receptors (AChRs), relative to the rate of acetylcholine removal, excludes this kinetic state from shaping synaptic responses in normal neuromuscular transmission, its role in neuromuscular disorders has not been examined. The slow-channel congenital myasthenic syndrome (SCCMS) is a disorder caused by point mutations in the AChR subunit-encoding genes leading to kinetically abnormal (slow) channels, reduced miniature endplate current amplitudes (MEPCs), and degeneration of the postsynaptic membrane. Because of this complicated picture of kinetic and structural change in the neuromuscular junction, it is difficult to assess the importance of the multiple factors that may be responsible for the reduced endplate current amplitudes, and ultimately the clinical syndrome. In order to address this we have used a transgenic mouse model for the SCCMS that has slow AChR ion channels and reduced endplate responsiveness in the absence of any of the degenerative changes. We found that the reduction in MEPC amplitudes in these mice could not be explained by either reduced AChR number or by reduced AChR channel conductance. Rather, we found that the mutant AChRs in situ manifested an activity-dependent reduction in sensitivity that caused diminished MEPC and endplate current amplitude with nerve stimulation. This observation demonstrates that the basis for the reduction in MEPC amplitudes in the SCCMS may be multifactorial. Moreover, these findings demonstrate that, under conditions that alter their rate of desensitization, the kinetic properties of nicotinic AChRs can control the strength of synaptic responses.     

Gastric mucosal biopsy via a nasogastric tube: a nonendoscopic method for diagnosing fundic and antral mucosal gastritis and Helicobacter pylori infection in man

Synthesis of poly(gamma-glutamate) metabolites of natural folates and antifolates is a critical process. Folypolyglutamates are essential for cell proliferation. Polyglutamates of glutamate (Glu)-containing antifolates are often critical for their cytotoxic action and are relevant to antifolate resistance. However, the role of polyglutamate synthesis in selectivity is less clear. We have undertaken a research program to further define the significance of polyglutamate metabolism and to devise ways to exploit this metabolism to achieve greater therapeutic selectivity in cancer chemotherapy. This article briefly reviews several approaches tested thus far. Inhibition of folypolyglutamate synthesis should lead to cell death. Current ornithine (Orn)-containing folate-based inhibitors of the enzyme responsible for their synthesis, folypolyglutamate synthetase (FPGS), are poorly transported, apparently because of interference by the protonated delta-amine. Replacement of Orn with 4, 4-difluoroOrn, the delta-amine of which has a much lower pKa and is thus less protonated at physiological pH, was explored. Since it is unclear how polyglutamylation contributes to selectivity, we explored generic means either to eliminate or to enhance polyglutamylation. The data indicate that substitution for Glu in an antifolate by some Glu analogs in which the gamma-COOH is either altered or replaced (e.g., gamma-tetrazole-Glu) leads to loss of both FPGS substrate activity and binding; antifolate target specificity is unchanged, while uptake is actually enhanced. Substitution of 3,3-difluoroGlu for Glu leads to enhanced polyglutamylation (although probably only to the diglutamate), retention of target specificity, and at least equal uptake. Comparative studies of the same antifolate containing different replacements for Glu, such as gamma-tetrazole-Glu (no polyglutamylation) or 3,3-difluoroGlu (enhanced polyglutamylation), will be useful in exploring the role and significance of polyglutamylation.     

Common region of ALL-1 gene disrupted in epipodophyllotoxin-related secondary acute myeloid leukemia

Translocations at chromosomal band 11q23 characterize most de novo acute lymphoblastic leukemias (ALL) of infants, acute myeloid leukemias (AML) of infants and young children, and secondary AMLs following epipodophyllotoxin exposure. The chromosomal breakpoints at 11q23 have been cloned from isolated cases of de novo ALL and AML. Using an 859-base pair BamHI fragment of human ALL-1 complementary DNA that recognizes the genomic breakpoint region for de novo ALL and AML, we investigated two cases of secondary AML that followed etoposide-treated primary B-lineage ALL. In the first case, the translocation occurred between chromosomes 9 and 11 and the breakpoint at 11q23 localized to the same 9-kilobase region of the ALL-1 gene that is disrupted in most of the de novo leukemias. In the second case the translocation was between chromosomes 11 and 19. The breakpoint occurred outside of the ALL-1 breakpoint cluster region.