Indian Ocean corals reveal crucial role of World War II bias for twentieth century warming estimates.

The western Indian Ocean has been warming faster than any other tropical ocean during the 20th century, and is the largest contributor to the global mean sea surface temperature (SST) rise. However, the temporal pattern of Indian Ocean warming is poorly constrained and depends on the historical SST product. As all SST products are derived from the International Comprehensive Ocean-Atmosphere dataset (ICOADS), it is challenging to evaluate which product is superior. Here, we present a new, independent SST reconstruction from a set of Porites coral geochemical records from the western Indian Ocean. Our coral reconstruction shows that the World War II bias in the historical sea surface temperature record is the main reason for the differences between the SST products, and affects western Indian Ocean and global mean temperature trends. The 20th century Indian Ocean warming pattern portrayed by the corals is consistent with the SST product from the Hadley Centre (HadSST3), and suggests that the latter should be used in climate studies that include Indian Ocean SSTs. Our data shows that multi-core coral temperature reconstructions help to evaluate the SST products. Proxy records can provide estimates of 20th century SST that are truly independent from the ICOADS data base.

Antarctic ice sheet discharge driven by atmosphere-ocean feedbacks at the Last Glacial Termination.

Reconstructing the dynamic response of the Antarctic ice sheets to warming during the Last Glacial Termination (LGT; 18,000-11,650 yrs ago) allows us to disentangle ice-climate feedbacks that are key to improving future projections. Whilst the sequence of events during this period is reasonably well-known, relatively poor chronological control has precluded precise alignment of ice, atmospheric and marine records, making it difficult to assess relationships between Antarctic ice-sheet (AIS) dynamics, climate change and sea level. Here we present results from a highly-resolved 'horizontal ice core' from the Weddell Sea Embayment, which records millennial-scale AIS dynamics across this extensive region. Counterintuitively, we find AIS mass-loss across the full duration of the Antarctic Cold Reversal (ACR; 14,600-12,700 yrs ago), with stabilisation during the subsequent millennia of atmospheric warming. Earth-system and ice-sheet modelling suggests these contrasting trends were likely Antarctic-wide, sustained by feedbacks amplified by the delivery of Circumpolar Deep Water onto the continental shelf. Given the anti-phase relationship between inter-hemispheric climate trends across the LGT our findings demonstrate that Southern Ocean-AIS feedbacks were controlled by global atmospheric teleconnections. With increasing stratification of the Southern Ocean and intensification of mid-latitude westerly winds today, such teleconnections could amplify AIS mass loss and accelerate global sea-level rise.

Millennial-scale variability in Antarctic ice-sheet discharge during the last deglaciation.

Our understanding of the deglacial evolution of the Antarctic Ice Sheet (AIS) following the Last Glacial Maximum (26,000-19,000 years ago) is based largely on a few well-dated but temporally and geographically restricted terrestrial and shallow-marine sequences. This sparseness limits our understanding of the dominant feedbacks between the AIS, Southern Hemisphere climate and global sea level. Marine records of iceberg-rafted debris (IBRD) provide a nearly continuous signal of ice-sheet dynamics and variability. IBRD records from the North Atlantic Ocean have been widely used to reconstruct variability in Northern Hemisphere ice sheets, but comparable records from the Southern Ocean of the AIS are lacking because of the low resolution and large dating uncertainties in existing sediment cores. Here we present two well-dated, high-resolution IBRD records that capture a spatially integrated signal of AIS variability during the last deglaciation. We document eight events of increased iceberg flux from various parts of the AIS between 20,000 and 9,000 years ago, in marked contrast to previous scenarios which identified the main AIS retreat as occurring after meltwater pulse 1A and continuing into the late Holocene epoch. The highest IBRD flux occurred 14,600 years ago, providing the first direct evidence for an Antarctic contribution to meltwater pulse 1A. Climate model simulations with AIS freshwater forcing identify a positive feedback between poleward transport of Circumpolar Deep Water, subsurface warming and AIS melt, suggesting that small perturbations to the ice sheet can be substantially enhanced, providing a possible mechanism for rapid sea-level rise.

Comparison of the efficacy and safety of two formulations of diclofenac sodium 0.1% eyedrops in controlling postoperative inflammation after cataract surgery.

PURPOSE: To compare the efficacy and safety of diclofenac sodium 0.1% eyedrops packaged in an Abak multidose container without preservative (Dicloabak) with the reference product, sodium merthiolate-preserved diclofenac sodium 0.1% eyedrops, in controlling postoperative inflammation after cataract surgery. METHODS: The multicenter, controlled, randomized, single-masked study included 194 patients (Dicloabak 96, preserved diclofenac 98) scheduled to have cataract surgery by phacoemulsification with foldable intraocular lens. All were evaluated preoperatively and postoperatively after 1, 7, and 28 days. Postoperative inflammation was measured by the total score of anterior chamber cells and flare. Ocular plin, conjunctival hyperemia and ciliary flush were also assessed. Postoperative patient assessments also included visual acuity, objective tolerance by slit-lamp, fluorescein test, and subjective evaluation of local tolerance. RESULTS: There was no statistically significant difference between the groups in the total score of flare and cells or the degree of conjunctival hyperemia and ciliary flush at any study visit. Dicloabak was demonstrated to be not inferior to preserved diclofenac at all assessment times. The overall assessment of local tolerance was similar for both study medications. CONCLUSIONS: Preservative suppression did not alter diclofenac efficacy. Results support the good safety profile of both formulations when dosed three times daily for 4 weeks in absence of concomitant use of drugs potentially toxic for cornea. Preservative-free formulations like Dicloabak should be preferred to generic diclofenac formulations including other ingredients and may improve the safety profile of this topical nonsteroid anti-inflammatory drug.

Microgravity culture reduces apoptosis and increases the differentiation of a human colorectal carcinoma cell line.

Our hypothesis is that rotation increases apoptosis in standard tissue culture medium at shear stresses of greater than approximately 0.3 dyn/cm2. Human MIP-101 poorly differentiated colorectal carcinoma cells were cultured for 6 d in complete medium in monolayers, on Teflon-coated nonadherent surfaces (static three-dimensional [3D]) or in rotating 3D cultures either in microgravity in low-earth orbit (3D microg) or in unit gravity on the ground (3D 1g). Apoptosis (determined morphologically), proliferation (by MIB1 staining), and the expression of epidermal growth-factor receptor (EGF-R), TGF-alpha, or TGF-beta were assessed by immunohistochemistry, while the expression of the differentiation marker carcinoembryonic antigen (CEA) was assessed on Western blots. Over the course of 6 d, static 3D cultures displayed the highest rates of proliferation and lowest apoptosis. This was associated with high EGF-R, TGF-alpha, and TGF-beta expression which was greater than that of a monolayer culture. Both rotated 3D lg and 3D microg cultures displayed lower expression of EGF-R, TGF-alpha, or TGF-beta and proliferation than that of monolayer or static 3D cultures. However, rotated 3D microg displayed significantly less apoptosis and greater CEA expression than rotated 3D 1g cultures. When rotated cultures of MIP-101 cells were grown uncler static conditions for another 3 d, proliferation increased and apoptosis decreased. Thus, rotation appears to increase apoptosis and decrease proliferation, whereas static 3D cultures in either unit or microgravity have less apoptosis, and reduced rotation in microgravity increases CEA expression.

Effect of low-dose oral contraceptives on androgenic markers and acne.

Oral contraceptives (OC) suppress excess androgen production; however, different progestins in combination with low-dose estrogens produce divergent effects on sex hormone-binding globulin (SHBG) and testosterone that may influence clinical outcomes. This multicenter, open-label, randomized study compared biochemical androgen profiles and clinical outcomes associated with two OC containing the same amounts of ethinyl estradiol (EE, 20 micrograms) but different progestins, levonorgestrel (LNG, 100 micrograms), and norethindrone acetate (NETA, 1000 micrograms). Fifty-eight healthy women (18-28 years old) received three cycles of treatment with LNG/EE (n = 30) or NETA/EE (n = 28). The results showed that LNG reduced androgen levels in three compartments--adrenal, ovarian, and peripheral. NETA reduced only adrenal and peripheral androgens. Despite a 2.2-fold greater relative increase in SHBG with NETA than LNG, bioavailable testosterone (T) was reduced by the same amount with LNG and NETA. Both treatments improved acne and were well tolerated. Low-dose OC (EE, 20 micrograms) are effective in reducing circulating androgens and acne lesions without causing weight gain. Although LNG and NETA affected secondary markers differently, both OC formulations produced an equivalent decrease in bioavailable.

PIP: Oral contraceptives (OCs) suppress excess androgen production; however, different progestins in combination with low-dose estrogens produce divergent effects on sex hormone-binding globulin (SHBG) and testosterone that may influence clinical outcomes. This multicenter, open-label, randomized study compared biochemical androgen profiles and clinical outcomes associated with 2 OCs containing the same amounts of ethinyl estradiol (EE, 20 mcg) but different progestins, levonorgestrel (LNG, 100 mcg), and norethindrone acetate (NETA, 1000 mcg). 58 healthy women aged 18-28 years received 3 cycles of treatment with LNG/EE (n = 30) or NETA/EE (n = 28). The results showed that LNG reduced androgen levels in 3 compartments-adrenal, ovarian, and peripheral. NETA reduced only adrenal and peripheral androgens. Despite a 2.2-fold greater relative increase in SHBG with NETA than LNG, bioavailable testosterone (T) was reduced by the same amount with LNG and NETA. Both treatments improved acne and were well tolerated. Low-dose OC (EE, 20 mcg) are effective in reducing circulating androgens and acne lesions without causing weight gain. Although LNG and NETA affected secondary markers differently, both OC formulations produced an equivalent decrease in bioavailable T.

Management of irregular uterine bleeding and spotting associated with Norplant.

Norplant, a systemic contraceptive, has been used extensively throughout the world. A major problem for consumers utilizing Norplant has been irregular, unpredictable uterine bleeding or spotting. This study seeks to determine whether or not an appropriate treatment could be found that will reduce the incidence of spotting and bleeding. Both a pilot study and an interim report of a multi-center trial utilizing ethinyl estradiol 20 micrograms for 10 days, versus Ibuprofen 800 mg three times a day for 5 days, versus placebo is reported. Based on the interim analysis of the multi-center trial, there is a reduction in the mean number of spotting days with one of the three treatments compared to the other two treatments (p = 0.044). There was no difference in the number of bleeding days between treatment regimen. It appears from a review of the literature that both oestrogen, progesterone, and non-steriodal anti-inflammatory agents may reduce the number of bleeding days or inhibit acutely the bleeding in women utilizing Norplant. The completion of this randomized multi-center trial will hopefully give us further insight into an effective treatment for controlling the irregular bleeding and/or spotting that occurs in Norplant users.

PIP: A review of the literature suggests that estrogen, progesterone, and nonsteroidal anti-inflammatory agents have the potential to ameliorate the prolonged bleeding associated with Norplant use. The feasibility of such treatment was investigated in both a pilot study and a multicenter trial. In the pilot study, bleeding episodes were stopped within 5 days (average, 3.1 days) in 8 of the 10 Norplant acceptors with irregular bleeding who received 20 mcg of ethinyl estradiol for 10 days. On the basis of this finding, 44 Norplant users from 5 US sites were administered 20 mcg of ethinyl estradiol for 10 days, 800 mg of ibuprofen 3 times a day for 5 days, or a placebo. Interim analysis of data from the multicenter trial suggests that 1 of these regimens (unknown at this point due to the double-blind nature of the study) produces a reduction in the mean number of spotting days, but there is no difference by treatment group in the number of bleeding days. The mean number of spotting days was reduced (0.23 +or- 0.44) in Group A compared to Group C (1.94 +or- 1.34) during the first 5 days of treatment. The overall mean number of bleeding days was 1.34 days in the first 5 days after treatment initiation and 0.82 during the second 5 days of treatment. Completion of the multicenter trial analysis should provide guidelines on ways to improve the menstrual disturbances that are the major barrier to Norplant use.

Effect of the concentration of DODMAC and 1-decanol on the behavior of reverse micelles in the extraction of amino acids.

The concentrations of dioctyldimethyl ammonium chloride (DODMAC) and 1-decanol in isooctane needed to form reverse micelles by phase contact have been determined. The behavior of these reverse micelles in the extraction of aspartic acid, glutamic acid, and threonine was studied by analyzing all of the ionic species in the aqueous phase. The amino acid is extracted from the aqueous phase by exchanging with the Cl(-) counterions of DODMAC in the reverse micelles. The ionic species in the reverse micelles tend toward their undissociated states as the water uptake by the reverse micelles decreases. The effect of 1-decanol on the extraction of the amino acids with two negative charges is due to the change in the water uptake of the reverse micelles. The concentration of DODMAC has no effect on the ion exchange of the amino acid with one negative charge with the Cl(-) counterions of DODMAC in the reverse micelles. Higher molar ratios of decanol to DODMAC favor the selective separation of amino acids with different charge numbers. (c) 1995 John Wiley & Sons, Inc.

Left infrarenal region: anatomic variants, pathologic conditions, and diagnostic pitfalls.

Computed tomography (CT) is the preferred method for evaluating the left periaortic infrarenal region. Structures larger than 11 mm in cross-sectional diameter in this region are considered abnormal and should be evaluated for lymphadenopathy, hydroureter, or a vascular abnormality such as venous thrombosis or varicoceles. Normal structures include inferior mesenteric vessels, left gonadal vein and artery, and ureter. The diagnostic process may be complicated by variations in anatomy, including double inferior vena cava, left inferior vena cava, retroaortic left renal vein, circumaortic left renal vein, horseshoe kidney, crossed-fused renal ectopia, renal agenesis, and ureteral duplication. Familiarity with the anatomy of this region and awareness of normal variants are necessary to avoid errors in diagnosis. Radiologists should also be aware of problems in CT technique (nonopacified bowel, dynamic and unenhanced scanning) that can confuse the diagnosis.

Effect of large palpable ovarian follicles on response to prostaglandin administration in dairy cows with corpora lutea.

We examined the response to exogenous prostaglandin F2alpha in cattle with or without palpable structures believed to be ovarian follicles. All animals had ovarian structures diagnosed by palpation as corpora lutea. The cows were placed into two groups: those with follicles which were estimated by the palpators to be

Mucus transport by high-frequency nonsymmetrical oscillatory airflow.

To study air-mucus interaction as a possible mechanism of tracheal mucus transport and to test the validity of using surface tracer displacement to indicate bulk mucus transport, we performed a combined experimental-theoretical study. We hypothesized that the mucus mass is moved by the difference between expiratory and inspiratory velocities. The rate of transport of a layer of simulated mucus lining the bottom of a rectangular trough was measured in two ways during oscillatory air flow. Peak velocity ratios (R) from 1.0 to 2.0, frequencies (f) between 7 and 13 Hz, and tidal volumes (VT) between 50 and 100 ml were generated by a custom-made pump. The experimental results demonstrate that measuring the displacement of a tracer deposited on the surface of the mucus layer is equivalent to measuring bulk mucus movement by weight. Moreover the measured mucus velocities (micron) correlate well with a theoretical model which predicts that micron is proportional to delta VT f1.5 (R-1). These results suggest that shearing at the air-mucus interface could be a significant factor in the enhanced tracheal mucus clearance during high-frequency chest wall oscillation.

Velocity profiles in central airways with endotracheal intubation: a model study.

Steady inspiratory velocity profiles were measured at two flow rates in a 3:1 scale model of the human central airways in the presence of five modes of endotracheal intubation. The presence of an orifice or a short endotracheal tube had no significant effect on the velocity profiles distal to the carina. Long endotracheal tubes change the profiles in both main bronchi. A significant peak occurred in the frontal plane near the walls, and the maximum velocity in the airway was almost identical to the endotracheal tube center-line velocity. The flow impinging on the medial wall of the main bronchus was redirected up around the anterior and posterior walls yielding bipeak velocity profiles in the sagittal plane. A tube placed eccentrically in the trachea over the right main bronchus did not alter the velocity profiles in the left main bronchus, suggesting a redirection of flow over the carina into the left lung. An endobronchial tube at the mouth of the right main bronchus did change the shape of the velocity profiles in the left main bronchus. In the left upper lobar bronchus the presence of trachea intubation had no effect on the velocity profiles. However, in the right upper lobar bronchus, the long endotracheal tube flattened the velocity profiles from the strongly skewed ones seen in the absence of the endotracheal inserts. These results not only are relevant to distribution of ventilation and aerosol particle deposition, but also have strong implications in intrapulmonary gas mixing, especially when high-frequency low tidal-volume ventilation is involved.

Effect of the larynx on oscillatory flow in the central airways: a model study.

Measurements were made of the effect of the larynx on the oscillatory flow profiles in a 3:1 scale model of the human central airways. A fixed glottic aperture corresponding to the shape and size at midinspiration was used. Oscillatory airflows at peak Reynolds numbers, similar to those obtained during spontaneous breathing and panting, were studied. The flow distribution to the five lobar bronchi was maintained by distally placed linear resistors. A hot-wire anemometer probe was used to measure the local velocity along two perpendicular diameters at six stations distributed through the model. Near the proximal end of the trachea, the flat velocity profiles at the beginning of the flow cycle peaked at maximum flow because of the jet created by the glottic aperture. This peaked structure was conserved during the latter half of the inspiratory cycle. Close to the carina, the jet had almost dissipated and the entry conditions into the main bronchi corresponded to those in the absence of the laryngeal model. The effect of the glottic aperture on the mean velocity was not felt beyond the carina, and the characteristic skewed profiles seen in oscillatory flows, in the absence of the larynx, were present in the main and lobar bronchi.

The effect of surgical excision and grafting procedures on postburn lymphocyte suppression.

Previous reports have stressed the immunosuppressive effects of major surgical procedures. In this study, 30 adult patients with a mean burn size of 42.8% TBSA and a mean age of 31.9 years underwent 78 surgical excision and grafting (E/G) procedures. The mean surface area excised was 2,373 cm2, with a mean blood transfusion requirement per E/G of 3,355 cc or 1.4 cc/cm2. The suppressive effect of burn serum was assayed in mixed lymphocyte cultures. Before E/G, burn serum caused a mean 42.2 +/- 3.3% suppression of normal lymphocyte blastogenesis; serum suppressive activity following E/G was reduced to 29.1 +/- 2.9% (p less than 0.005). The mean duration of improvement in lymphocyte function was 5.0 days. E/G procedures which achieved complete burn wound closure were more effective in restoring lymphocyte immunocompetence. E/G has a significant beneficial effect on restoring lymphocyte responsiveness in burn patients. Preliminary evidence suggests that this effect is related to blood transfusions.

Model study of flow dynamics in human central airways. Part III: Oscillatory velocity profiles.

Measurements of oscillatory velocity were made in a 3:1 model of the human central airways. The model was built of acrylic plastic and mounted vertically. A reciprocating pump connected to the upper end of the model privided oscillatory flow frequencies of 0.25, 1, 2 and 4 Hz (equivalent to 2.25, 9, 18 and 36 Hz in the actual airways) and tidal volumes of 300, 500 and 1500 ml. A hot-wire anemometer probe was used to measure velocities along two perpendicular diameters and at six stations distributed through the model. The flow distribution through the five lobar bronchi was controlled by distally positioned linear resistors . The measurements indicate that the entry flow profile into the model during oscillatory flow was essentially flat. At low frequencies, the velocity profiles attained at peak flow rate resemble the profiles seen under steady flow conditions at the corresponding Reynolds number. In the frontal plant these profiles are asymmetric with a maximum in velocity directed towards the outer wall of the bend. In the sagittal plane the velocity profiles are symmetric and have the characteristic bi-peak (M-shaped) structure seen in the steady flows. However, as the frequency increases the velocity profiles throughout most branches tend to flatten except in the right upper lobar bronchus where the skewed velocity profiles persist even at the highest frequencies studied. As in steady flows the nature of the velocity profile is strongly influenced by the airway geometry. Furthermore, the peak velocity profiles resemble steady flow profiles at comparable Reynolds numbers up to a Womersley number of 16.

The effect of plasma exchange on lymphocyte suppression after burn.

Circulating mediators have been implicated in the pathophysiology of immunodepression after burn injury, suggesting the beneficial effect of plasma exchange in immunorestoration. In this study, 19 adult patients with a mean burn size of 52.2% of total body surface area and mean age of 33.4 years underwent 51 plasma exchange procedures in five different clinical settings, without complication. The suppressive effect of burn serum was assayed in mixed lymphocyte cultures. The mean (+/- SEM) suppression by burn serum drawn prior to plasma exchange was 61.9% +/- 3.6%, while that following plasma exchange was 27.3% +/- 2.7%. The lymphocyte response decrease 55.1% +/- 4.4% in suppressive activity. The mean duration of improvement in lymphocyte function was 4.8 days. Plasma exchange has a significant beneficial effect in restoring lymphocyte immunocompetence in burned patients in a number of clinical settings.

Resistance of mucus-lined tubes to steady and oscillatory airflow.

We examined the effects of quantity and physical properties of mucus on resistance to steady and oscillatory flows in a circular tube. Gels with similar rheological properties to canine tracheal mucus were prepared from hog gastric mucin or locust bean gum cross-linked with Na2B4O7. A horizontal straight tube (D 1.85 cm) was lined with these mucus simulants to depths ranging from 0.3 to 1.0 mm. The pressure difference over a 50-cm portion of the tube and the volumetric flow rate were determined simultaneously. Low-amplitude oscillatory flow were generated with a modified Harvard pump. For steady flow, the resistance at low Reynolds number (Re) increased with increasing gel depth only to the extent expected for simple constriction of the tube cross-sectional area. The same was true for oscillatory (0.25--6 Hz) flow resistance at low flow amplitude (corresponding to Re less than 4,000). No effect of gel cross-link density at low Re was observed. At high steady-flow rates, and for high-amplitude oscillatory flow, resistance increased beyond that predicted for simple constriction. Plots of friction factor (f) vs. Re showed a critical point (Recrit) of the order of 1.5 x 10(4), at which f increased sharply. Recrit, which corresponded to the onset of wave formation in the lining layer, was insensitive to changes in gel depth. However, gel cross-link density did affect the onset of wave formation: in oscillatory flow Recrit was shifted to higher Re, and the rise in f in steady flow was blunted with high degrees of cross-linking. The existence of Recrit and its association with wave formation are consistent with predictions based on two-phase flow theory.

Hydrodynamic features of pulmonary air embolism: a model study.

To elucidate the hydrodynamic events during pulmonary air embolism, experiments were conducted in a branching-tube apparatus and in small vessels. It was found that, as long as there existed an elevation differential between the two branches of a bifurcation, the vast majority of air bubbles always entered the higher branch. This finding is explained in terms of buoyancy, shear forces, and liquid flow velocity and is consistent with the in vivo finding of increased blood perfusion in the dependent lung regions during air embolization (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 51: 211-217, 1981). The pressures required to drive air bubbles through various small vessels were determined using three aqueous solutions of different surface tensions. Based on these measurements and a theoretical analysis, the diameter of air bubbles that could not pass through the pulmonary vessels was calculated to be 20-30 micrometers, agreeing well with a recent in vivo measurement (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 47: 537-543, 1979).