RESUMEN

This study presents an optical assembly and digital reconstruction method that is based on digital holography for characterizing transparent objects. The image-plane optical setup is based on a versatile Mach-Zehnder interferometer for the formation of controlled parallel fringe patterns, of tens micrometers of separations or less. The numerical reconstruction of the propagated wavefront by the hologram is performed by the Fresnel-Kirchhoff transform, and it is used of three ways: (a) interferometric phase reconstruction (as in interferometry) in the phase object position, (b) reconstruction of the wavefront amplitude at a determined distance from the object (shadowgraph technique), and (c) a composed digital reconstruction process of the wavefront amplitude, defined by a digital optical assembly for the selection of angular deflections produced by the phase object (schlieren technique). The resolving power of holographic reconstruction methodology proposed is determined by the sensitivity of hologram for detecting the interferometric phase. The fringe pattern of the hologram defines a minimum phase shift resolution of 0.15π rad. The scope of the technique is experimentally tested for a steady-state phase object.

RESUMEN

BACKGROUND: In this study, we retrospectively analyzed the recurrence of hepatitis B virus (HBV) and hepatitis D virus (HDV) infection after liver transplantation for HBV and HBV+HDV co-infection. METHODS: Data from patients infected with HBV and HBV+HDV who underwent liver transplantation between March 2003 and June 2013 at the Liver Transplantation Institute of Inonu University were analyzed retrospectively. A total of 255 patients were included in the study. Group 1 (n = 127) comprised patients who underwent liver transplantation because of HBV, and group 2 (n = 128) comprised patients who underwent liver transplantation because of HBV+HDV. A positive HDV antibody serologic test result was taken to indicate liver disease caused by HBV+HDV. RESULTS: Thirteen of 255 were positive for the HBs Ag (5.1%). Nine (7.1%) and 4 (3.1%) patients were positive for the HBs Ag in groups 1 and 2, respectively (7.1%); the difference was not significant (P = .150). No HDV recurrence was detected in either group. The average time to HBs Ag seroconversion in 13 patients was 7.8 months after surgery (6.34 months in group 1 and 11.1 months in group 2). CONCLUSIONS: In our study, recurrence rate of HBV after liver transplantation is not statistically different than the recurrence rate of HBV+HDV co-infection. A low recurrence rate was achieved by the prophylaxis protocol in use at our center. There is no standard protocol for prevention of HBV and HDV recurrence; therefore, we need new studies.

Asunto(s)

RESUMEN

The present study was designed to determine the involvement of central prostaglandin synthesis on the pressor and bradycardic effect of cytidine 5'-diphosphocholine (CDP-choline). Intracerebroventricular (i.c.v.) administration of CDP-choline was made and blood pressure and heart rate were recorded in male Sprague Dawley rats throughout this study. Microdialysis and immunohistochemical studies were performed to measure extracellular total prostaglandin concentration and to show cyclooxygenase-1 and -2 (COX-1 and -2) immunoreactivities, respectively, in the posterior hypothalamic area. Moreover, rats were pretreated (i.c.v) with mepacrine [a phospholipase A2 (PLA2) inhibitor], ibuprofen [a nonselective COX inhibitor], neomycine [a phospholipase C (PLC) inhibitor] or furegrelate [a thromboxane A2 (TXA2) synthesis inhibitor] 5 min prior to the injection of CDP-choline to determine the effects of these inhibitors on cardiovascular responses to CDP-choline. Control rats were pretreated (i.c.v) with saline. CDP-choline caused a dose- and time-dependent increase in blood pressure and decrease in heart rate. Immunohistochemical studies showed that CDP-choline increased COX-1 and -2 immunoreactivities in the posterior hypothalamic area. CDP-choline also elevated hypothalamic extracellular total prostaglandin concentration by 62%, as shown in microdialysis studies. Mepacrine or ibuprofen pretreatments almost completely blocked the pressor and bradycardic responses to CDP-choline while neomycine or furegrelate partially attenuated the drug-induced cardiovascular effects. The results suggest that CDP-choline may stimulate prostaglandin synthesis through the activation of PLA2, cyclooxygenases (COX-1 and -2) and prostaglandins and at least TXA2, may mediate the drug׳s cardiovascular effects.

Asunto(s)

RESUMEN

CDP-choline is an endogenous metabolite in phosphatidylcholine biosynthesis. Exogenous administration of CDP-choline has been shown to affect brain metabolism and to exhibit cardiovascular, neuroendocrine neuroprotective actions. On the other hand, little is known regarding its respiratory actions and/or central mechanism of its respiratory effect. Therefore the current study was designed to investigate the possible effects of centrally injected CDP-choline on respiratory system and the mediation of the central cholinergic receptors and phospholipase to thromboxane signaling pathway on CDP-choline-induced respiratory effects in anaesthetized rats. Intracerebroventricularly (i.c.v.) administration of CDP-choline induced dose- and time-dependent increased respiratory rates, tidal volume and minute ventilation of male anaesthetized Spraque Dawley rats. I.c.v. pretreatment with atropine failed to alter the hyperventilation responses to CDP-choline whereas mecamylamine, cholinergic nicotinic receptor antagonist, mepacrine, phospholipase A2 inhibitor, and neomycin phospholipase C inhibitor, blocked completely the hyperventilation induced by CDP-choline. In addition, central pretreatment with furegrelate, thromboxane A2 synthesis inhibitor, also partially blocked CDP-choline-evoked hyperventilation effects. These data show that centrally administered CDP-choline induces hyperventilation which is mediated by activation of central nicotinic receptors and phospholipase to thromboxane signaling pathway.

Asunto(s)

RESUMEN

The effect of concentration and addition method of glycerol on the quality of cryopreserved mithun (Bos frontalis) spermatozoa was investigated. Semen samples were collected from five healthy mithun bulls through rectal massage method and cryopreserved in liquid nitrogen. The samples were diluted in Tris-egg yolk-glycerol extender, equilibrated for 4 h at 4 °C and loaded into 0.50-ml straws. The straws were then frozen in liquid nitrogen vapour for 10 min and finally plunged into liquid nitrogen for storage. The required amount of glycerol was added into the diluted samples either in a single dose (3%, 4%, 5%, 6% or 7%; added at 37 °C immediately before equilibration) or in split doses (5%, 6% or 7%; the total amount was divided into four equal parts, and a part was added at 37 °C immediately before equilibration, and the remaining parts were added subsequently at 1, 2 and 3 h of equilibration at 4 °C). In the single-dose addition method, following freeze-thawing, greater (p < 0.05) motility (%) and proportion of live spermatozoa with intact acrosome (LSIA, %) in 5% glycerol (40.6 ± 1.7 and 43.4 ± 1.8 respectively) and lesser (p < 0.05) total morphological abnormalities (%) in 5% (14.1 ± 0.8) and 6% (13.7 ± 1.0) glycerol were observed compared to the other glycerol concentrations. In the split-dose addition method, following freeze-thawing, greater (p < 0.05) motility (%) and LSIA proportion (%) were found in 5% (50.2 ± 1.9 and 53.3 ± 1.8 respectively) compared to 6% or 7% glycerol, but the total morphological abnormalities were not different among the glycerol concentrations. In addition, in all the glycerol concentrations, better (p < 0.05) post-freeze-thaw motility and LSIA proportions were observed when glycerol was added in split doses compared to a single dose. In conclusion, Tris-egg yolk extender with 5% glycerol added in split doses was found most suitable for cryopreserving mithun sperm.

Asunto(s)

RESUMEN

Melittin is a polypeptide component of bee venom that leads to an increase in arachidonic acid release and subsequently in prostaglandin synthesis by activating phospholipase A(2). Recently we demonstrated that centrally or peripherally administrated melittin caused pressor effect and central thromboxane A(2) (TXA(2)) and cholinergic system mediated these effects of melittin. Also centrally injected histamine leads to pressor and bradycardic response by activating central histamine receptors in normotensive rats and central cholinergic system involved the effects of histamine. The present study demonstrates an involvement of the central histaminergic system in melittin-induced cardiovascular effect in normotensive rats. Experiments were carried out in male Sprague Dawley rats. Intracerebroventricularly (i.c.v.) injected melittin (0.5, 1 and 2 nmol) caused dose- and time-dependent increases in mean arterial pressure (MAP) and decrease in heart rate (HR) as we reported previously. Moreover, H(2) receptor antagonist ranitidine (50 nmol; i.c.v.) almost completely and H(3)/H(4) receptor antagonist thioperamide (50 nmol; i.c.v.) partly blocked melittin-evoked cardiovascular effects, whereas H(1) receptor blocker chlorpheniramine (50 nmol; i.c.v.) had no effect. Also centrally injected melittin was accompanied by 28% increase in extracellular histamine concentration in the posterior hypothalamus, as shown in microdialysis studies. In conclusion, results show that centrally administered melittin causes pressor and bradycardic response in conscious rats. Moreover, according to our findings, there is an involvement of the central histaminergic system in melittin-induced cardiovascular effects.

Asunto(s)

RESUMEN

The objective of this study was to test the efficacy of induction of estrus, synchronization of ovulation and timed artificial insemination in anestrous yaks using the Heatsynch protocol. In Experiment 1, 10 anestrous yaks were administered an analogue of gonadotropin releasing hormone (GnRH) followed by prostaglandin (PG)F2alpha 7 days later and then estradiol cyponate (ECP) 24 h after that. Ovulation was detected by rectal palpation at 2h intervals beginning at the initial signs of estrus. Blood samples were collected at 2h intervals beginning at the time of ECP injection up to 2h after the occurrence of ovulation for the determination of LH and progesterone. All the animals responded to the Heatsynch protocol with expression of estrus and synchronization of ovulation. The mean time interval from the ECP injection to ovulation was 59.4+/-2.62 h (range 50-72 h). The interval from the LH peak to ovulation was 30.2+/-2.3 h. The high degree of synchrony in ovulation could be attributed to the synchrony in the timing of LH peaks. In Experiment 2, 10 anestrous yaks were treated with the Heatsynch protocol (as in Experiment 1) and TAI was performed at 48 and 60 h after the ECP treatment. Concurrently, 16 cycling yaks were inseminated approximately 12 h after detection of spontaneous estrus. Pregnancy rates were similar in both groups, 40% for TAI and 43.75% for yaks inseminated following spontaneous estrus (p>0.05). From this study, two conclusions can be drawn. First, the Heatsynch protocol can be successfully used to induce and synchronize estrus in anestrous yaks and, second, ovulation following the Heatsynch protocol is synchronized adequately to permit the use of fixed time AI in this species.

Asunto(s)

RESUMEN

As an alternative to radioimmunoassays, a simple, highly sensitive and quick enzymeimmunoassay (EIA) for determination of cortisol in blood plasma of yaks on microtiterplates using second antibody coating technique and cortisol-horseradish peroxidase as a label has been developed. The wells of the microtiterplate were coated with affinity-purified goat IgG (antirabbit IgG) that binds the hormone specific antibody. The EIA was carried out directly in 20 microl of heat treated plasma after 1:5 dilution with PBS. The cortisol standard curve, with doses ranged from 0.4 to 100 pg/well. The sensitivity of the assay was 20 pg/ml. Cortisol standard curve in buffer showed parallelism with serially diluted yak plasma containing high endogenous cortisol. Intra- and inter-assay coefficients of variation (CV) determined using pooled plasma was found 6.58 and 11.35%, respectively. Recovery of known concentrations of added cortisol in charcoal stripped plasma was linear (r = 0.98). For biological validation of cortisol enzymeimmunoassay, the blood samples were collected from yak cows at -48 and -24h before and 0, 12, 24, 36, 48, 60, 72, 84 and 96 h after dexamethasone administration. The plasma cortisol before dexamethasone administration was significantly (P < 0.05) higher than after dexamethasone administration. The developed EIA was further validated biologically by estimating cortisol in peri-parturient cows beginning day 10 prior to calving till day 10 post-calving; the concentrations were along with the expected lines as reported in bovine. In conclusion, the EIA developed in this study is simple, highly sensitive, valid and sufficiently reliable method for estimation of cortisol directly in bovine plasma.

Asunto(s)

RESUMEN

We use a modified Mach-Zehnder interferometer to measure surface displacement resulting from the thermoelastic response of a target to the absorption of a short laser pulse with axial and temporal resolutions of 0.1 nm and 3 ns, respectively. These measurements are used in conjunction with a solution to the thermoelastic wave equation and a nonlinear optimization algorithm to extract optical attenuation depth. We demonstrate the ability to determine the effective optical attenuation depth of homogeneous targets with either diffuse or specular reflecting surfaces with a precision of

Asunto(s)

RESUMEN

We introduce a minimally invasive technique for optoacoustic imaging of turbid media using optical interferometric detection of surface displacement produced by thermoelastic stress transients. The technique exploits endogenous or exogenous optical contrast of heterogeneous tissues and the low attenuation of stress wave propagation to localize and image subsurface absorbers in optically turbid media. We present a system that utilizes a time-resolved high-resolution interferometer capable of angstrom-level displacement resolution and nanosecond temporal resolution to detect subsurface blood vessels within model tissue phantoms and a human forearm in vivo.

Asunto(s)

RESUMEN

BACKGROUND: Noise and vibration are stressors that may adversely affect the well-being of infants and children being transported between facilities. Although the problem has been recognized, little has been done to rectify the situation. HYPOTHESIS: That noise levels in transport incubators during use in transport vehicles exceed the recommended standards, and that vibration levels exceed those that are "very uncomfortable" for healthy adults. METHODS: We measured noise and vibration (n/v) levels inside and outside a neonatal transport incubator in seven transport vehicles (land, air, and water), and calculated maximum and average, weighted and unweighted levels. RESULTS: The maximum and average unweighted noise levels in all but one vehicle were over 99 dB. The incubator amplified noise at the lower frequencies (The Canadian Standards Association 1992 recommendation is that the noise level in transport incubators not exceed 60 dBA). The maximum vibration levels ranged from 0.86 m.S-2 to 2.35 m.S-2, and the average levels ranged from 0.33 m.S-2 to 1.46 m.S-2. (Vibration in excess of 1.5 is considered "very uncomfortable," and in excess of 2.0 is "extremely uncomfortable" for healthy adults.) CONCLUSIONS: Noise and vibration levels inside transport incubators in our most-commonly used transport vehicles often exceed the recommended limits. For neurologically immature and/or physiologically compromised infants and children, current levels of n/v in transport vehicles are too high, and could affect patient morbidity. These n/v levels require further study, and modification of equipment, primarily the incubators, is overdue.

Asunto(s)

RESUMEN

Postoperative infection after hip joint replacement is an uncommon but potentially devastating complication in contemporary orthopaedics. Management in two stages is the more favored approach in North America. This introduces difficulty with patient management in the interval between stages, delays rehabilitation, and introduces technical difficulty during the second stage. A method has been developed whereby a temporary antibiotic-loaded facsimile of the hip is introduced at the first stage, designed to maintain stability of the joint, length of the limb, and mobility of the patient. It has been used in a total of 86 cases to date. The results in 46 cases with a minimum follow-up of 2 years are reviewed in this article. The infection was controlled in 93.5% of cases.

Asunto(s)

RESUMEN

Two-stage exchange arthroplasty is currently the method of choice in the treatment of the infected knee replacement. The prosthesis of antibiotic-loaded acrylic cement (PROSTALAC) is a temporary, antibiotic-loaded functional prosthesis that is used as an interim spacer in two-stage exchange arthroplasty. In this prospective series, we report on the early results of the use of the PROSTALAC knee spacer in two-stage exchange arthroplasty of infected knees. A total of 24 knees were treated with this prosthesis, and were reviewed at a mean follow-up time of 2.2 years. Infection was controlled in all but 2 knees, for an infection cure rate of 91.7%. The patients' function was improved between stages, and motion was maintained in the majority of cases. The significant complications with the PROSTALAC implant in place were tibio-femoral instability, which was corrected with a design modification, and patellar instability, which continues to be a problem. These complications were transient and were not of any significance after the second stage.

Asunto(s)