The origin of blinking in both mudskippers and tetrapods is linked to life on land

Blinking, the transient occlusion of the eye by one or more membranes, serves several functions including wetting, protecting, and cleaning the eye. This behavior is seen in nearly all living tetrapods and absent in other extant sarcopterygian lineages suggesting that it might have arisen during the water-to-land transition. Unfortunately, our understanding of the origin of blinking has been limited by a lack of known anatomical correlates of the behavior in the fossil record and a paucity of comparative functional studies. To understand how and why blinking originates, we leverage mudskippers (Oxudercinae), a clade of amphibious fishes that have convergently evolved blinking. Using microcomputed tomography and histology, we analyzed two mudskipper species, Periophthalmus barbarus and Periophthalmodon septemradiatus, and compared them to the fully aquatic round goby, Neogobius melanostomus. Study of gross anatomy and epithelial microstructure shows that mudskippers have not evolved novel musculature or glands to blink. Behavioral analyses show the blinks of mudskippers are functionally convergent with those of tetrapods: P. barbarus blinks more often under high-evaporation conditions to wet the eye, a blink reflex protects the eye from physical insult, and a single blink can fully clean the cornea of particulates. Thus, eye retraction in concert with a passive occlusal membrane can achieve functions associated with life on land. Osteological correlates of eye retraction are present in the earliest limbed vertebrates, suggesting blinking capability. In both mudskippers and tetrapods, therefore, the origin of this multifunctional innovation is likely explained by selection for increasingly terrestrial lifestyles.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Effect of Acute Administration of Recombinant Human Leptin during the Neonatal Period on Body Temperature and Endocrine Profile of the Piglet

BACKGROUND

Leptin is produced predominantly by white adipocytes; in adults it regulates appetite and energy expenditure but its role in the neonate remains to be fully established.

OBJECTIVES

To examine the effects of acute administration of recombinant human leptin on the endocrine profile and thermoregulation of neonatal pigs.

METHODS

24 pairs of siblings (n = 48) were administered with either a single dose (4 microg ml(-1) kg(-1) body weight) of leptin (L: n = 24) or a placebo (P: n = 24) on day 6 of neonatal life. Rectal temperature was recorded, and tissue samples were taken at 1 (n = 12), 2 (n = 12), 4 (n = 12) or 6 (n = 12) hours post-administration. Plasma concentrations of hormones and metabolites were determined in conjunction with messenger RNA (mRNA) for leptin and uncoupling protein-2.

RESULTS

Plasma leptin increased following leptin administration, and differences in concentrations of insulin, thyroxine and non-esterified fatty acids were observed between the two groups. Initially, rectal temperature decreased in L pigs but returned to start values by 1.5 h. This decline in rectal temperature was delayed in placebo animals, resulting in differences between treatments at 1.5 and 2 h.

CONCLUSIONS

Acute leptin administration alters the endocrine profile of pigs and influences the thermoregulatory ability of the neonate.

State-of-the-art burn treatment

The death rate per 100,000 workers fell to just four in 1994, but there were 3.5 million disabling injuries. The cost associated with deaths and injuries was $120.7 billion that year.

Distributed testing and measurement across the Atlantic packet satellite network(SATNET)

The analysis of the test and measurement of TCP/IP performance over the Atlantic Packet Satellite Network (SATNET) is described. Both the methodology and tools as well as the results and their analysis are discussed. Because of the Internetwork nature of the environment, the tests were designed to allow the SATNET Measurement Taskforce to look at the effects of each component of the end-to-end path, e.g., local networks, gateways, SATNET, and protocol layers. Results are given for the IP service provided by SATNET as a function of offered load and for TCP behavior as a function of offered load and the underlying IP service.

Newer techniques in the diagnosis and treatment of proximal bile duct carcinoma--an analysis of 41 consecutive patients

The clinical course of 41 consecutive patients with primary bile duct carcinoma at or near the liver hilum was analysed to determine whether the outcome was improved by newer techniques of diagnosis and treatment. The age range was wide, with one third under 50 years. The only aetiological factor identified was long-standing ulcerative colitis (present in 9.8 per cent of patients). In one third of patients initial symptoms were misleading. The tumour had been missed in 11 (61 per cent) of 18 patients undergoing an exploratory laparotomy at other hospitals, despite operative cholangiography. None had pre-operative percutaneous cholangiography which was shown to be the best investigatory technique, giving the correct diagnosis in all cases in whom it was performed. Greyscale ultrasonography was useful and endoscopic retrograde cholangiography less so. Median survival in those treated by surgical T- or U-tube drainage (21 patients) or bypass (three) was nine months from diagnosis, as opposed to three months in the 36.5 per cent of patients in whom biliary drainage was not obtained. Radiotherapy, including insertion of a radioactive iridium wire through the tumour via a T- or U-tube, or percutaneously, was performed in nine patients and improved the duration of survival compared with tube drainage alone. The new percutaneous techniques offer a useful alternative to surgery for palliative drainage and radiotherapy.

Non-invasive techniques in the diagnosis of jaundice--ultrasound and computer

This study describes the use of ultrasound in 84 consecutive patients to distinguish between medical (intrahepatic) and surgical (extrahepatic) types of jaundice. Accuracy rates in the 84 patients investigated were compared with those found in 169 patients using the computer-aided diagnostic model for jaundice. In 50 patients in whom both techniques were carried out direct comparison was possible. Ultrasound failed to give adequate visualisation for technical reasons in two patients, but 75 of the remaining 82 (91.5%) were correctly separated into medical and surgical categories. A similar percentage (90%, 152 of 169 patients) were correctly classified by the computer-assisted model, and in the 50 patients assessed by both techniques correct diagnostic separation was achieved in 43 (86%) by ultrasound and in 42 (84%) by computer. However, in this latter group two of the errors with computer diagnosis were falsely positive for a surgical jaundice (extrahepatic obstruction), and a surgical exploration performed on the basis of this test could have been unnecessary. This was not found with ultrasound in these same patients, all the errors being false negative. A high degree of confidence can therefore be attached to the demonstration by ultrasound of a dilated biliary tree.

Ligation of the hepatic artery in the treatment of heart failure due to hepatic haemangiomatosis

An infant presenting with high-output cardiac failure and a single large diffuse haemangioma of the liver is described. Corticosteroid therapy failed to produce any improvement, but hepatic artery ligation was followed by dramatic disappearance of the signs of cardiac failure and a decrease in the size of the liver without any evidence of lasting liver damage.

Bronchopneumonia with serious sequelae in children with evidence of adenovirus type 21 infection

Twenty-five cases of severe pneumonitis occurring among children aged 3 to 18 months were observed in Auckland, New Zealand, in 1965. An apparent relationship was established between a uniform disease picture and recovery of adenovirus type 21. Two died, and of the survivors 60% had permanent lung damage, probably resulting from obliterative bronchiolitis. Twenty per cent. were left with proved bronchiectasis. The possible relationships of adenovirus pneumonia to malnutrition or a genetic factor on the one hand and to the development of bronchiectasis on the other are discussed.