Oxygen transport characterization of a human model of progressive hemorrhage

Background

Hemorrhage continues to be a leading cause of death from trauma sustained both in combat and in the civilian setting. New models of hemorrhage may add value in both improving our understanding of the physiologic responses to severe bleeding and as platforms to develop and test new monitoring and therapeutic techniques. We examined changes in oxygen transport produced by central volume redistribution in humans using lower body negative pressure (LBNP) as a potential mimetic of hemorrhage.

Methods and results

In 20 healthy volunteers, systemic oxygen delivery and oxygen consumption, skeletal muscle oxygenation and oral mucosa perfusion were measured over increasing levels of LBNP to the point of hemodynamic decompensation. With sequential reductions in central blood volume, progressive reductions in oxygen delivery and tissue oxygenation and perfusion parameters were noted, while no changes were observed in systemic oxygen uptake or markers of anaerobic metabolism in the blood (e.g., lactate, base excess). While blood pressure decreased and heart rate increased during LBNP, these changes occurred later than the reductions in tissue oxygenation and perfusion.

Conclusions

These findings indicate that LBNP induces changes in oxygen transport consistent with the compensatory phase of hemorrhage, but that a frank state of shock (delivery-dependent oxygen consumption) does not occur. LBNP may therefore serve as a model to better understand a variety of compensatory physiological changes that occur during the pre-shock phase of hemorrhage in conscious humans. As such, LBNP may be a useful platform from which to develop and test new monitoring capabilities for identifying the need for intervention during the early phases of hemorrhage to prevent a patient's progression to overt shock.     

Pattern of hepatitis virus infection among pregnant women and their newborns at the Women's Health Center of Assiut University, Upper Egypt

Objective

To determine the prevalence, risk factors, and rate of vertical transmission of HBV and/or HCV infection among pregnant women in Upper Egypt, and assess the preventive efficacy of administering hepatitis B immunoglobulin and vaccine to newborns on their carrier status at 8 months.

Methods

Five hundred pregnant women were screened for HCV and HBV serum markers by enzyme-linked immunoassay. Those testing positive had their status confirmed by polymerase chain reaction and their levels of liver enzymes and interferon gamma were evaluated. The newborns of HBV-positive women received hepatitis B immunoglobulin and vaccine and were followed up to assess the rates of vertical transmission and carrier status among the newborns.

Results

Of the 500 pregnant women, 6.4% were HCV positive, 4.0% were HBV positive, and 1.0% were both. The vertical transmission rate was 3.1% for HCV, 30.0% for HBV, and 20.0% for a combined infection. The carrier rate of the infants at the end of their eighth month was 10.8% for those with HCV and 8% for those with HBV.

Conclusion

Infection with HBV and/or HCV is highly prevalent among pregnant women in Upper Egypt. The rate of vertical transmission was also high. Administering hepatitis B vaccine and immunoglobulin resulted in a 92% reduction in carrier status among newborns.     

Computed tomography-assisted laparoscopic removal of intraabdominally migrated levonorgestrel-releasing intrauterine systems

Purpose  

To report three cases of migrated levonorgestrel intrauterine device (LNG-IUS) into the pelvic/abdominal cavity removed laparoscopically with the aid of preoperative computed tomography (CT) scan imaging.     

Synthesis of a [18F]labeled chelidonine derivative as a possible antitumor agent.

[(+/-)-[5bRS-(5b alpha, 6beta, 12b alpha)]-5b,6,7,12b,13,14-hexahydro-13-methyl[1,3]benzodioxolo[5,6-c]-1,3-dioxolo[4,5-1] phenanthridin-6-yl]-4-[18F]fluorobenzoate (6b) an aromatic ester of chelidonine was prepared as a possible PET radiotracer. Compound (6b) was prepared in no-carrier-added (n.c.a) form from the 4-N,N,N-trimethylanilinium triflate derivative (5) in one step. The best results were obtained using Kryptofix(2.2.2)/[18F] and DMSO as the solvent at 90 degrees C. Column chromatography afforded the desired compound in overall radiochemical yield of 65-70% (EOS) with a specific activity of about 3000 Ci/mmole and radiochemical purity greater than 95% in 15 min.     

Nondestructive quantification of analyte diffusion in cornea and sclera using optical coherence tomography

PURPOSE: Noninvasive functional imaging, monitoring, and quantification of analytes transport in epithelial ocular tissues are extremely important for therapy and diagnostics of many eye diseases. In this study the authors investigated the capability of optical coherence tomography (OCT) for noninvasive monitoring and quantification of diffusion of different analytes in sclera and cornea of rabbit eyes. METHODS: A portable time-domain OCT system with wavelength of 1310 +/- 15 nm, output power of 3.5 mW, and resolution of 25 mum was used in this study. Diffusion of different analytes was monitored and quantified in rabbit cornea and sclera of whole eyeballs. Diffusion of water, metronidazole (0.5%), dexamethasone (0.2%), ciprofloxacin (0.3%), mannitol (20%), and glucose solution (20%) were examined, and their permeability coefficients were calculated by using OCT signal slope and depth-resolved amplitude methods. RESULTS: Permeability coefficients were calculated as a function of time and tissue depth. For instance, mannitol was found to have a permeability coefficient of (8.99 +/- 1.43) x 10(-6) cm/s in cornea and (6.18 +/- 1.08) x 10(-6) cm/s in sclera. The permeability coefficient of drugs with small concentrations (where water was the major solvent) was found to be in the range of that of water in the same tissue type, whereas permeability coefficients of higher concentrated solutions varied significantly. CONCLUSIONS: Results suggest that the OCT technique might be a powerful tool for noninvasive diffusion studies of different analytes in ocular tissues. However, additional methods of OCT signal acquisition and processing are required to study the diffusion of agents of small concentrations.     

Robot-Assisted Antegrade In-Situ Fenestrated Stent Grafting

To determine the technical feasibility of a novel approach of in-situ fenestration of aortic stent grafts by using a remotely controlled robotic steerable catheter system in the porcine model. A 65-kg pig underwent robot-assisted bilateral antegrade in-situ renal fenestration of an abdominal aortic stent graft with subsequent successful deployment of a bare metal stent into the right renal artery. A 16-mm iliac extension covered stent served as the porcine aortic endograft. Under fluoroscopic guidance, the graft was punctured with a 20-G customized diathermy needle that was introduced and kept in place by the robotic arm. The needle was exchanged for a 4 × 20 mm cutting balloon before successful deployment of the renal stent. Robot-assisted antegrade in-situ fenestration is technically feasible in a large mammalian model. The robotic system enables precise manipulation, stable positioning, and minimum instrumentation of the aorta and its branches while minimizing radiation exposure.     

Association between risk of breast cancer and fertility factors - a latent variable approach

Background: Breast cancer is the most common malignant tumor in females. Many studies have been carried out in order to assess the reproductive risk factors. Particular attention has focused on information regarding fertility, including breastfeeding, age at first birth and number of live births. These factors are highly correlated with each other. The objective of this study was to employ latent variables to reduce the confounding effect of this correlation with a logistic regression analysis. Methods: The investigation drew upon results from a dataset belonged to a hospital based case-control study covering 303 breast cancer patients and 303 hospital controls. Data were collected through interview and reproductive variables included age at first full-term pregnancy and live birth, number of pregnancies and live births, and total length of breast feeding. Latent variables were generated using factor analysis and principal components analysis. Results: The study revealed that for both latent variable approaches the odds ratios of two latent variables significantly indicated a protective impact of number of pregnancy and live birth and breastfeeding and a prognostic relation with age at first pregnancy or live birth. Conclusion: The findings suggest that breastfeeding and decreasing age at first live birth have protective influences on breast cancer risk. Also using statistical model with latent variables in the presence of collinear data leads to reliable results.     

Mechanisms by which sleep disturbance contributes to osteoarthritis pain: A conceptual model

Sleep disturbance is prevalent in aging and painful rheumatologic populations, but it has largely been a neglected dimension of the routine clinical care of arthritis patients. Pain associated with osteoarthritis (OA) is a leading cause of disability worldwide, and factors that contribute to pain in OA are poorly understood. Sleep disturbance is not only a consequence of pain, it is also likely to play an integral role in pain expression. Emerging research suggests that many patients with OA demonstrate signs of generalized hyperalgesia and faulty central pain modulatory processing similar to other idiopathic pain disorders, such as fibromyalgia. Sleep disruption is increasingly recognized as a direct contributor to both hyperalgesia and impaired endogenous pain modulation. This article reviews the extant literature on sleep disturbance and hyperalgesia in patients with OA. We propose a conceptual working model describing pathways by which sleep disturbance interacts directly with central pain processing mechanisms and inflammatory processes, and indirectly with mood and physical functioning to augment clinical OA pain. The clinical and research implications of the model are discussed.     

N-Substituted piperazinyl quinolones as potential cytotoxic agents: Structure–activity relationships study

As part of a continuing search for new potential anticancer candidates in the piperazinyl quinolone series, the cytotoxicity evaluation of new N-substituted piperazinyl quinolones was of our interest. The growth inhibitory activities of 12 new compounds, namely N-[2-(5-chlorothiophen-2-yl)-2-oxoethyl] and N-[2-(5-chlorothiophen-2-yl)-2-oxyiminoethyl] piperazinyl quinolones 1–12 were determined against six cancer cell lines using MTT colorimetric assay. Preliminary screening showed that most of the new N-[2-(5-chlorothiophen-2-yl)ethyl]piperazinyl quinolones 4–12 containing (un)substituted oxime moiety showed significant cytotoxic activity and the modification of functionality on ethyl spacer produced a relatively minor change of activity. Thus, in the piperazinyl quinolone series, cytotoxic activity can be positively modulated through the introduction of 2-(5-chlorothiophen-2-yl)ethyl residue on the piperazine ring. The results revealed that the introduction of 2-(5-chlorothiophen-2-yl)ethyl moiety on the piperazine ring of quinolone antibacterials (ciprofloxacin, norfloxacin and enoxacin) changes the biological profile of piperazinyl quinolones from antibacterials to cytotoxic agents.