The fetoplacental pressor effects of low-dose acetylsalicylic acid and angiotensin II in the ex vivo cotyledon model

OBJECTIVE: Our purpose was to investigate perfusion pressure changes ex vivo induced by angiotensin II on fetoplacental vasculature pretreated with low-dose acetylsalicylic acid. STUDY DESIGN: Two cotyledons from each of 12 placentas were perfused. The intervillous space of one cotyledon was infused with acetylsalicylic acid (5 x 10(-5) mol/L) similar to the serum concentration of women receiving daily low-dose aspirin therapy (60 to 81 mg). The control cotyledon was infused with an equivalent amount of normal saline solution. Two doses of angiotensin II, 1 x 10(-11.5) and 1 x 10(-10) moles, were injected as boluses into the chorionic arteries of each cotyledon. A 3 x 10(-7) mole dose of angiotensin II was also injected into the intervillous space. Statistical analysis was performed with analysis of variance, and results are expressed as mean pressure change in millimeters of mercury +/- SEM. RESULTS: Perfusion pressure response did not vary between cotyledons pretreated with acetylsalicylic acid and control cotyledons when 3 x 10(-7) moles of angiotensin II was injected into the intervillous space (8.0 +/- 1.9 mm Hg vs 9.8 +/- 1.6 mm Hg, p = 0.59). There were no differences between cotyledons in pressure response to 1 x 10(-11.5) moles of angiotensin II injected into the fetal circuit (5.9 +/- 0.8 mm Hg vs 6.7 +/- 0.9 mm Hg, p = 0.51). However, in the cotyledons pretreated with acetylsalicylic acid there was a decrease in the pressor response to 1 x 10(-10) moles of angiotensin II (14.1 +/- 1.4 mm Hg vs 21.5 +/- 3.3 mm Hg, p = 0.05). CONCLUSIONS: Low-dose aspirin infused into the intervillous space decreases vasoconstriction elicited by angiotensin II in the fetoplacental compartment. This suggests that maternal low-dose aspirin therapy has effects in the fetoplacental circulation in addition to its effects in the maternal circulation.     

A high deuterium abundance at redshift z = 0.7

Of the light elements, the primordial abundance of deuterium relative to hydrogen, (D/H)p, provides the most sensitive diagnostic for the cosmological mass density parameter, omegaB. Recent high-redshift D/H measurements are highly discrepant, although this may reflect observational uncertainties. The larger primordial D/H values imply a low omegaB (requiring the Universe to be dominated by non-baryonic matter), and cause problems for galactic chemical evolution models, which have difficulty in reproducing the steep decline in D/H to the present-day values. Conversely, the lower D/H values measured at high redshift imply an omegaB greater than that derived from 7Li and 4He abundance measurements, and may require a deuterium-abundance evolution that is too low to easily explain. Here we report the first measurement of D/H at intermediate redshift (z = 0.7010), in a gas cloud selected to minimize observational uncertainties. Our analysis yields a value of D/H ((2.0 +/- 0.5) x 10[-4]) which is at the upper end of the range of values measured at high redshifts. This finding, together with other independent observations, suggests that there may be inhomogeneity in (D/H)p of at least a factor of ten.     

Spatial discrimination against background with different optical systems for collection of fluorescence in laser-excited atomic fluorescence spectrometry with a graphite tube electrothermal atomizer

A single 90 degrees off-axis ellipsoidal mirror fragment was used in a dispersive detection system for electrothermal atomization laser-excited atomic fluorescence spectrometry. The performance of the new optical arrangement was compared with those of optical arrangements that employed a plane mirror in combination with biconvex or plano-convex lenses. All the optical arrangements collected fluorescence in a scheme called front surface illustration. BEAM-4, an optical ray tracing program, was used for calculations of spatial ray distributions and optical collection efficiency for the various optical configurations. Experimentally, the best collection efficiency was obtained by use of the ellipsoidal mirror, in qualitative agreement with simulations done by use of the BEAM-4 software. The best detection limit for cobalt with the new optical arrangement was 20 fg, which was a factor of 5 better than that obtained with conventional optical arrangements with otherwise the same instrumentation. The signal-to-background ratio and the fluorescence collection efficiency were also studied as a function of position of the optical components for the various optical arrangements. For both cobalt and phosphorus, the signal-to-background ratio with the new optical arrangement remained stable within 10-20% during +/- 8 mm shifts in the position of the detection system from the focal plane of the optics. Overall, the new optical arrangement offered high collection efficiency, excellent sensitivity, and facile optical alignment due to efficient spatial separation between the fluorescence signal and the background radiation. The advantages of the new optical arrangement were particularly important during measurements in the presence of high levels of blackbody radiation.     

Prostatic cryosurgery: use of MR imaging in evaluation of success and technical modifications

PURPOSE: To evaluate the usefulness of contrast material-enhanced magnetic resonance (MR) imaging in objective assessment of prostatic cryosurgery and the role of MR imaging in the modification of prostatic cryosurgical technique. MATERIALS AND METHODS: Thirty-eight consecutive patients with localized (T1-3, N0, M0) prostatic adenocarcinoma treated with prostatic cryosurgery underwent MR imaging without contrast enhancement before cryosurgery and unenhanced and gadolinium-enhanced MR imaging within 1-3 weeks after cryosurgery. The first 20 patients also underwent MR imaging at 3 months after cryosurgery. MR imaging findings were correlated with those from transrectal ultrasound-directed prostatic staging biopsy. RESULTS: Cryonecrotic prostate was identified as avascular regions characterized by absolute signal void on contrast-enhanced images. With progressive modification of cryosurgical technique, complete cryoablation of the prostate was achieved in the latter nine of the 38 patients. When cryoablation was considered complete according to MR imaging criteria, findings invariably correlated with those at biopsy, with no residual prostate tissue or tumor. CONCLUSION: Gadolinium-enhanced MR imaging of the prostate after cryosurgery provides a highly accurate means of monitoring success. Objective MR imaging findings allow modifications to the technology and technique, resulting in optimal therapeutic results with prostatic cryosurgery.     

Metabolic efficiency during arm and leg exercise at the same relative intensities

This study was conducted to compare gross efficiency (GE), net efficiency (NE), work efficiency (WE), and delta efficiency (DE) between arm crank and cycle exercise at the same relative intensities. Eight college-aged males underwent two experimental trials presented in a randomized counterbalanced order. During each trial subjects performed three intermittent 7-min exercise bouts separated by 10-min rest intervals on an arm or semirecumbent leg ergometer. The power outputs for the three bouts of arm crank or cycle exercise corresponded to 50, 60, and 70% of the mode-specific VO2peak. GE, NE, and WE were determined as the ratio of Kcal.min-1 equivalent of power output to Kcal.min-1 of total energy expended, energy expended above rest and energy expended above unloaded exercise, respectively. DE was determined as the ratio of the increment of Kcal.min-1 of power output above the previous lower intensity to the increment of kcal.min-1 of total energy expended above the previous lower intensity. GE and NE did not differ between arm crank and cycle exercises. However, WE was lower (P < 0.05) during arm crank than cycle exercise at 50, 60, and 70% VO2peak. DE was also lower (P < 0.05) during arm crank than cycle exercise at delta 50-60 and at delta 60-70% VO2peak. It is concluded metabolic efficiency as determined by work and delta efficiency indices was lower during arm crank compared with cycle exercise at the same relative intensities. These findings add to the understanding of the difference in metabolic efficiency between upper and lower body exercise.     

Intraoperative end-tidal carbon dioxide values and derived calculations correlated with outcome: prognosis and capnography

OBJECTIVE: To determine how much information concerning resuscitation and outcome is provided by the end-tidal CO2 and derived variables obtained during surgery. DESIGN: Retrospective chart review. SETTING: Emergency hospital operating room. PATIENTS: One hundred critically ill or injured patients requiring major surgery and having a mortality rate of 41%. INTERVENTIONS: Standard intraoperative monitoring, including continuous capnography, plus arterial blood gas analyses every 1 to 1.5 hrs during surgery. MEASUREMENTS AND MAIN RESULTS: There was only a fair correlation between the PaCO2 and end-tidal CO2 (r2 = .14). The mortality rates in these patients were highest in those patients who had the lowest end-tidal CO2 values, the highest arterial to end-tidal CO2 differences, and the highest estimated alveolar deadspace fraction. A persistent end-tidal CO2 of < or = 28 torr (< or = 3.8 kPa) was associated with a mortality rate of 55% (vs. 17% in those patients with a higher end-tidal CO2). The mortality rate was also increased in patients with a persistent arterial to end-tidal CO2 difference of > or = 8 torr (> or = 1.1 kPa) (58% vs. 23%). CONCLUSIONS: End-tidal CO2 and derived values should be monitored closely in critically ill or injured patients. Efforts should be made--by increasing cardiac output and core temperature and by adjusting ventilation as needed--to maintain the end-tidal CO2 at > or = 29 torr (> or = 3.9 kPa) and the arterial to end-tidal CO2 difference at < or = 7 torr (< or = 1.0 kPa).     

Mission to the West Indies

A population medical genetic study of spinal muscular atrophies (SMA) was carried out in 1800 individuals in 6 russian and 3 middle asian regions. 33 patients with SMA were ascertained including 29 with autosomal recessive childhood proximal SMA (SMA I-III) and 4 patients with rare SMA types. There were revealed either overlapping of diagnostic criteria of I-III types in some patients or interfamilial differences of types in 3 from 6 familial cases, (one of them with distant relatives affected as well as pronounced clinical genetic variability of rare forms of SMA (all sporadic cases).     

A portable, real-time, clinical gait velocity analysis system

A direct ultrasound ranging system (DURS) has been developed for the quantitative evaluation of gait velocity. DURS consists of a transponder worn by the subject, a base unit infrared (IR) emitter/ultrasound (US) receiver, and a laptop computer. During gait analysis the transponder is worn by the subject at the approximate level of the body center of mass. As the subject walks away from the base unit his or her forward progression is displayed in real-time on the computer. At the end of the walking trial the instantaneous velocity profile, or gait velocigram (GVG), for that trial is displayed on the computer screen. From the GVG, parameters such as, gait speed, cadence, step length, step time, peak-to-peak variation, and time to achieve steady state walking are calculated and displayed. In addition gait deviations are readily apparent on the GVG.     

The acute abdomen. An overview and algorithms

The diagnosis and management of the patient with an acute abdomen remains one of the most difficult challenges for the surgeon. A thorough understanding of the anatomy and physiology of the abdomen are essential to properly generate a differential diagnosis and to formulate a treatment plan. While recent advances in technology can be extremely helpful in certain situations, they cannot replace a physician's clinical judgment based upon a good history and physical examination. This article provides a general overview of the evaluation of the patient with an acute abdomen. It will also suggest algorithms to consider in the diagnosis and treatment of these patients.