Antarctic glaciation caused ocean circulation changes at the Eocene-Oligocene transition.

Two main hypotheses compete to explain global cooling and the abrupt growth of the Antarctic ice sheet across the Eocene-Oligocene transition about 34 million years ago: thermal isolation of Antarctica due to southern ocean gateway opening, and declining atmospheric CO2 (refs 5, 6). Increases in ocean thermal stratification and circulation in proxies across the Eocene-Oligocene transition have been interpreted as a unique signature of gateway opening, but at present both mechanisms remain possible. Here, using a coupled ocean-atmosphere model, we show that the rise of Antarctic glaciation, rather than altered palaeogeography, is best able to explain the observed oceanographic changes. We find that growth of the Antarctic ice sheet caused enhanced northward transport of Antarctic intermediate water and invigorated the formation of Antarctic bottom water, fundamentally reorganizing ocean circulation. Conversely, gateway openings had much less impact on ocean thermal stratification and circulation. Our results support available evidence that CO2 drawdown--not gateway opening--caused Antarctic ice sheet growth, and further show that these feedbacks in turn altered ocean circulation. The precise timing and rate of glaciation, and thus its impacts on ocean circulation, reflect the balance between potentially positive feedbacks (increases in sea ice extent and enhanced primary productivity) and negative feedbacks (stronger southward heat transport and localized high-latitude warming). The Antarctic ice sheet had a complex, dynamic role in ocean circulation and heat fluxes during its initiation, and these processes are likely to operate in the future.

Accuracy assessment of NLCD 2011 impervious cover data for the Chesapeake Bay region, USA.

The National Land Cover Database (NLCD) contains three eras (2001, 2006, 2011) of percentage urban impervious cover (%IC) at the native pixel size (30 m-×-30 m) of the Landsat Thematic Mapper satellite. These data are potentially valuable to environmental managers and stakeholders because of the utility of %IC as an indicator of watershed and aquatic condition, but lack an accuracy assessment because of the absence of suitable reference data. Recently developed 1 m2 land cover data for the Chesapeake Bay region makes it possible to assess NLCD %IC accuracy for a 262,000 km2 region based on a census rather than a sample of reference data. We report agreement between the two %IC datasets for watersheds and the riparian zones within watersheds and four additional square units. The areas of the six assessment units were 40 ha cell, 433 ha (riparian mean), 2756 ha cell, 5626 ha cell, 8569 ha (watershed mean) and 22,500 ha cell. Mean Absolute Deviation (MAD) and Mean Deviation (MD) were about 1.5% and -1.5%, respectively, for each of the assessment units except for the riparian unit, for which MAD and MD were 0.88 and 0.62, respectively. NLCD reliably reproduced %IC from the 1 m2 data with a small, consistent tendency for underestimation. Results were sensitive to assessment unit choice. The results for the four largest assessment units had very similar regression parameters, R2 values, and bias patterns. Results for the riparian assessment were different from those for the watershed unit and the other three larger units. MAD was about 50% less for the riparian zones than it was for the watersheds, the direction of bias was less consistent, and NLCD %IC was uniformly higher than 1 m2 %IC in urbanized riparian zones. For the smallest unit, bias patterns were more similar to the riparian unit and regression results were more similar to the four larger units. MAD and MD were also sensitive to the amount of urbanization, increasing as NLCD %IC increased. The low overall bias and positive relationship between bias and urbanization suggest that the benefits of obtaining 1 m2 IC data outside of urban areas may not outweigh the costs of obtaining such data.

Measurements of behavior in the naked mole-rat after intraperitoneal implantation of a radio-telemetry system.

The naked mole-rat (Heterocephalus glaber) is a unique fossorial mammal that is eusocial, object blind, and virtually poikilothermic. This animal is an ideal model to examine questions pertaining to the thermoregulatory aspects of sleep/wake cycles and other circadian events. However, the monitoring of mammalian sleep usually involves implanting permanent electrodes into the skull which are linked to a counter-weighted cable apparatus. This is not a viable option for H. glaber because of the tunneled environments and sensitive social milieu. Instead, to monitor sleep, core temperature, and activity we have utilized intraperitoneal telemetry, a technique that transmits biopotential signals by radio waves. Here we describe the surgical procedure used to implant the device, the anesthesia technique developed, and the social reintroduction method devised for this novel animal model.

Intraventricular administration of a FIV-envelope protein induces sleep architecture changes in rats.

Fifteen adult male Sprague-Dawley rats were implanted with a set of electrodes for standard sleep recordings. A stainless steel cannula was also implanted into the lateral ventricle of these rats. Fifteen additional rats were implanted with a cannula alone. Rats with electrodes were habituated for 3 days or more to the recording environment, then placed into 3 groups (n = 5). One group received saline (i.c.v.), while the other two groups received either the feline immunodeficiency virus envelope glycoprotein (FIV SU-Env) or a fragment of the Epstein-Barr virus envelope glycoprotein (EB gp105). Rats were then recorded for electrographic sleep-wake cycle evaluation for the following 4 h. Core temperature was assessed through a thermistor probe inserted into the rectum, immediately before and 1, 2, 3 and 4 h after the i.c.v. treatment condition. Results demonstrated that compared to saline, FIV SU-Env increased wakefulness and decreased REM sleep throughout the 4 h of recording. Likewise, FIV SU-Env decreased SWS2 for 2 h. In addition, EB gp105 administration elicited minor modifications of the sleep-wake cycle, causing only a transient reduction of REM sleep in the first hour of recording. None of the treatments altered body temperature. These findings strongly support and extend studies in FIV-infected cats in which we have found similar sleep abnormalities. In addition, these results are consistent with the hypothesis that the FIV SU-Env proteins are responsible for these neurological disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

[Roller skating injuries]. / Rulleskøjteulykker.

The aim of this study was to investigate the number and types of accidents which occur in connection with roller-skates, and also to find out in which anatomical area the most injuries occurred. During the period 01.02.1995 to 31.08.1996, 389 patients sustained injuries in connection with roller-skates. Fifty-nine percent of all accidents happened on a public road. Out of 389 injuries, 174 sustained a fracture: 68% were forearm or distal radius/ulna fractures; 89% were upper extremity fractures. Thirty-three patients were admitted: four for observation due to concussion; 15 for reduction of fractures and application of plaster; and ten for osteosynthesis. Roller-skating accidents are extremely common. Possible prophylaxis includes protective equipment and restricted rinks for roller-skate enthusiast.

[Lifet-threatening hemorrhage from a mandibular hemangioma]. / Livstruende blødning fra haemangiom i underkaeben.

A case of a nine year-old girl with a life-threatening episode of profuse bleeding after extraction of a loose deciduous molar is reported. An angiography confirmed the presence of a haemangioma in the right side of the mandible. The lesion was superselectively embolized. Two days later exploration of the haemangioma and resection of the bone was performed, and the bleeding stopped. Special concern must be exercised in cases with hypermobility of the teeth, and when episodes of spontaneous haemorrhage are encountered.

["Moon-cars" are dangerous]. / "Moon-cars" er ikke ufarlige.

We investigated the number and seriousness of moon-car accidents in our region (a moon-car is a toy-vehicle, see Fig. 1). The study was retrospective combined with a telephone-interview. Forty-seven patients were seen in the emergency room after a moon-car accident in the period 1/1 1990-31/12 95. There were 12 fractures, including five fractures of the tibial shaft and one supracondylar humeral fracture which was operated. There were 17 wounds, 14 of which were sutured. Seventeen patients had distorsions/contusions, three cases of head contusions (observed for concussion) and two with teeth damages. We found that the number of moon-car accidents is increasing (13 patients the last year), and that the accidents are not only minor. New rules in day care centres should be able to especially limit the number of more serious accidents.

Imaging of serotonin transporters and its blockade by citalopram in patients with major depression using a novel SPECT ligand [123I]-ADAM.

We studied the midbrain SERT availability in patients with major depression and assessed the relation of SERT occupancy by citalopram to the treatment response. 21 non-medicated patients with major depression and 13 healthy controls were examined by [(123)I]-ADAM SPECT. The midbrain SERT availability (SERT V(3)'') was calculated using individual MRI scans. In 13/21 patients SPECT was repeated 7 days after oral medication with citalopram (10 mg/day). We found no significant difference in the mean midbrain SERT availability between the studied patients with major depression and healthy controls (0.86 +/- 0.27 vs. 0.71 +/- 0.44, p = 0.069). The mean SERT occupancy accounted to 61%. The degree of SERT blockade by citalopram did not correlate with the reduction in HAMD total score. Treatment with low-dosed citalopram caused individually variable occupancy of the midbrain-SERT and a rapid clinical improvement in 54% of the investigated patients.

Fibrillar collagen assembled in the presence of glycosaminoglycans to constitute bioartificial stem cell niches in vitro.

Fibrillar collagen was reconstituted from mixtures of monomeric tropocollagen and heparin or hyaluronic acid, respectively. Turbidity measurements were utilized to follow the fibrillar assembly and demonstrated the influence of the concentration of the glycosaminoglycan on the maximum optical densities. Thin film coatings of maleic anhydride copolymers were utilized for the covalent immobilization of the fibrillar assemblies to solid supports. Quantification of surface-bound collagen was accomplished by ellipsometry and HPLC-based amino acid analysis indicating that less collagen was immobilized in the presence of the glycosaminoglycans. SEM and AFM revealed various sizes and shapes of the immobilized fibrillar assemblies if collagen fibrils were prepared in the presence of heparin or hyaluronic acid. Human hematopoietic stem cells (HSCs) were cultivated on the surface-bound collagen fibrils and the migration of adherent cells was studied by time-lapse microscopy. Migration rates on fibrillar structures were significantly lower then on tropocollagen indicating a more intimate contact of HSCs to the fibrillar substrates.

Synovectomy and radial head excision in rheumatoid arthritis. 11 patients followed for 14 years.

A radial head excision and partial synovectomy of the elbow through a lateral approach was performed in 24 patients suffering from rheumatoid arthritis. At follow-up examination of 11 patients (12 elbows) 14 years postoperatively, 10 patients were still satisfied with pain reduction and improved elbow motion. 2 elbows had been reoperated on. Radiographic destruction, assessed by the Larsen index, was, on average, 2.9 preoperatively and 3.8 at follow-up.

[Ultrasound examination of the liver in HELLP syndrome]. / Ultraschalluntersuchung der Leber beim HELLP-Syndrom.

A 33-year-old multiparous woman in the 34th gestational week presented with severe upper abdominal pain, nausea and vomiting. Clinical examination revealed severe epigastric tenderness. Abdominal ultrasound examination showed geographical areas with increased echogenicity in the right lobe of the liver. Through haematological examination, we found severe thrombocytopenia and fibrinolysis. The diagnosis of HELLP syndrome was suspected and a caesarean section was performed. We suggest that obstetrical patients with upper abdominal pain and abnormal liver sonography should immediately be haematologically investigated to exclude the life-threatening condition of the HELLP syndrome.

A prospective comparison of wedge matrix resection with nail matrix phenolization for the treatment of ingrown toenail.

In a prospective study, 110 patients with ingrown toenails were operated on, 55 with wedge matrix resection (WMR) and 55 with nail matrix phenolization (NMP). The patients were randomized on the basis of their address. All patients were reviewed by questionnaire 4 weeks postoperatively to establish the degree of pain, time of pain relief, walking and working ability, and the presence of infection. Furthermore, they were examined clinically at a median follow-up time of 11 months postoperatively to evaluate recurrence rate, rate of spicula formation, and patient satisfaction with regard to cosmesis and symptom relief. The data were tested for statistical significance using the chi-square test and Mann-Whitney rank sum test. The recurrence rate of ingrown toenail for the WMR group was 5.5% (3 patients) with a spicula rate of 36% (20 patients) and a reoperation rate of 20% (9 patients). In the NMP group, there were no recurrences (p = n.s.), the spicula rate was 7.3% (4 patients) (p < .005) and no patients were reoperated on (p < .016). Patient satisfaction with less pain and earlier pain relief was greatest in the NMP group. These results indicate that nail matrix phenolization is an efficient therapy for ingrown toenails and may be preferable to nail wedge resection.

Sleep patterns are disturbed in cats infected with feline immunodeficiency virus.

Human immunodeficiency virus (HIV)-related sleep disturbances have been reported early in AIDS. Likewise, the feline immunodeficiency virus (FIV), a natural lentivirus pathogen of cats, produces a similar immunodeficiency syndrome with neurological sequelae. To identify the neurophysiological substrate of FIV infection in brain, pathogen-free cats were infected with the Maryland strain of FIV. Eight weeks after inoculation, all FIV-infected cats seroconverted and virus was detected in the cerebrospinal fluid and in the mononuclear cells of peripheral blood. Ten to 12 months after the FIV inoculation, inoculated and control cats were surgically implanted with electrodes to record the sleep/wake cycle. These sleep recordings were obtained under conditions controlling for environmental variables and instrumental adaptation. FIV-infected cats spent 50% more time awake than the sham-inoculated controls and exhibited many more sleep/waking stage shifts--i.e., 40% more than controls. In addition, FIV-infected cats showed approximately 30% of rapid eye movement (REM) sleep reduction compared to controls. The latency to sleep and REM sleep onset was also significantly delayed in FIV-infected cats. In addition, a remarkable increase in cortically recorded spindle activity (8-13 Hz) was observed during slow-wave sleep in some infected subjects, similar to changes described in HIV-infected humans. Moreover, infected cats exhibited no overt signs of systemic morbidity, such as hyperpyrexia or body weight loss. These results indicate that FIV-infected cats exhibit sleep abnormalities similar to the sleep disturbances previously described in AIDS patients and further support the feline preparation as a valuable animal model of HIV infection of the central nervous system.