The Evolution of Feeding Mechanics in the Danioninae, or Why Giant Danios Don't Suck Like Zebrafish.

By linking anatomical structure to mechanical performance we can improve our understanding of how selection shapes morphology. Here we examined the functional morphology of feeding in fishes of the subfamily Danioninae (order Cypriniformes) to determine aspects of cranial evolution connected with their trophic diversification. The Danioninae comprise three major lineages and each employs a different feeding strategy. We gathered data on skull form and function from species in each clade, then assessed their evolutionary dynamics using phylogenetic-comparative methods. Differences between clades are strongly associated with differences in jaw protrusion. The paedomorphic Danionella clade does not use jaw protrusion at all, members of the Danio clade use jaw protrusion for suction production and prey capture, and members of the sister clade to Danio (e.g., Devario and Microdevario) use jaw protrusion to retain prey after capture. The shape of the premaxillary bone is a major determinant of protrusion ability, and premaxilla morphology in each of these lineages is consistent with their protrusion strategies. Premaxilla shapes have evolved rapidly, which indicates that they have been subjected to strong selection. We compared premaxilla development in giant danio (Devario aequipinnatus) and zebrafish (Danio rerio) and discuss a developmental mechanism that could shift danionine fishes between the feeding strategies employed by these species and their respective clades. We also identified a highly integrated evolutionary module that has been an important factor in the evolution of trophic mechanics within the Danioninae.

Experimental evidence of cerebral injury from profound hypothermia during cardiopulmonary bypass.

Choreoathetosis, seizures, and impaired mental development continue to occur in children undergoing cardiopulmonary bypass (CPB) and profound hypothermia with or without circulatory arrest. Although there is some evidence that the hypothermia itself may be causing these neurologic problems, skepticism remains because of lack of evidence from experimental studies simulating the clinical setting. In this experimental study, we examined the effect of profound and moderate hypothermia on the brain while maintaining normal flow rates during CPB. Ten adult mongrel dogs equally divided into two groups were anesthetized and subjected to CPB and varying levels of hypothermia (group 1, < or = 15 degreesC; group 2, < or = 2 degreesC). Both groups were kept at the desired temperature for 1 hour prior to rewarming and discontinuation of CPB. The dogs were euthanized 4-6 weeks later and neuropathologic studies were performed. The mean CPB flow rates during cooling and at the desired rectal temperature were comparable in both groups: group 1, 108 +/- 10 ml/kg/min versus 106 +/- 7 ml/kg/min in group 2 (p = NS) and 95 +/- 12 ml/kg/min in group 1 versus 101 +/- 5 ml/kg/min in group 2 (p = NS). Because of the difference in temperature between the two groups, the mean cooling time (onset of CPB to desired rectal temperature) was longer in group 1 (70 +/- 14 minutes) than in group 2 (28 +/- 11 minutes, p = 0.007). Hence, the total mean CPB time was also longer in group 1 (198 +/- 25 minutes) than in group 2 (143 +/- 13 minutes, p = 0.002). The lowest mean blood and rectal temperature achieved in group 1 were 11 +/- .9 degreesC and 12 +/- 1 degreesC versus 29 +/- .4 degreesC (p < 0.001) and 30 +/- .6 degreesC (p = 0.001), respectively, in group 2 (p = 0.001). Neuronal loss and degeneration was noted in all dogs in group 1 ranging from 2 to 8 cells per 1000 cells counted compared to none in group 2 (p = 0.05). These lesions occurred in both the basal ganglia and the cortex, although they were more marked in the caudate when compared to the cortex and cerebellum. Both in the cortex and in the caudate, neuronal loss was more marked around the capillaries. We conclude that the use of profound hypothermia of < or =15 degreesC and maintenance of normal flow rates during cooling at this temperature for 1 hour produces neuronal loss and degeneration in the brain. These lesions being more marked around capillaries points to the vulnerability of the neurons, probably because of their high lipid content to injury from the cold perfusate.

[The possible transpacific travel of the adult T-cell leukemia virus I]. / El probable viaje transpacífico del virus tipo I de la leucemia de células T del adulto.

Genetical and archeological similarities in both Japanese and South American populations have been described. These facts along with the recent seroepidemiological studied on retroviruses performed in some of those racial groups, and published up to 1993, allow us to suggest that these retroviruses likely arrived to South America, not only from Africa, but also from The Far East since 6000 years ago or earlier. It could occur following the sea-currents directly.

The natural history of aortic stenosis in adults.

Accepted clinical views about the natural history of aortic stenosis are based on surprisingly little hemodynamically documented data, and further information in unlikely to be forthcoming in the modern surgical era. Therefore, follow-up data were obtained on 42 adult patients with isolated valvular aortic stenosis catheterized at Georgetown University Hospital who did not undergo early valve replacement. Of 32 symptomatic patients, 23 had moderate or severe stenosis and were followed until death or for an average of 64.4 months after catheterization. The prognosis was more ominous than previously reported. Mortality rates from onset of symptoms were 26% at one year, 48% at two years, and 57% at three years. Fifty-six % of deaths occurred suddenly, within hours of new symptoms. Asymptomatic patients with moderate or severe stenosis did not share the high mortality rate of those with symptoms. Eight such patients were followed for an average of 69.8 months, and none died.

Catering personnel and environmental health activities in Malumfashi and Samaru-Zaria Northern Nigeria.

A three month part-time training course in the basic principles of environmental health programmes with specific emphasis on practical food sanitation and control measures for food borne diseases, was organised for 79 members of the catering staff, of the Ahmadu Bello University (ABU) in Samaru-Zaria and Malumfashi, Northern Nigeria. The aims of the course were to instil in the participants, a new approach to food hygiene with a view to promoting proper catering qualities and also preventing or minimising the problems of the diarrhoeal diseases. The results, of the evaluation of the course contents and laboratory exercises are analysed and discussed. With the shortage and uneven distribution of medical and health manpower in Nigeria, all available staff in health and allied fields must be properly trained and utilised maximally in our fight against diseases and ignorance, whether such staff are hospital or community based.

"Mitral stenosis" secondary to combined "massive" mitral anular calcific deposits and small, hypertrophied left ventricles. Hemodynamic documentation in four patients.

Certain observations are described in four elderly women with massive mitral anular calcific deposits, small thick-walled left ventricles and diastolic gradients between pulmonary artery wedge position (or left atrium) and left ventricle. All four patients had some degree of obstruction to left ventricular outflow. Examination at necropsy (two patients) or at operation (one patient) disclosed only focal fibrous thickening of the mitral leaflets without commissural or chordal fusion. By auscultation, none had mitral opening snaps, only two had loud first heart sounds and only one had a mitral diastolic rumble. Hemodynamic documentation of a diastolic gradient between pulmonary artery wedge position (or left atrium) and left ventricle in the presence of massive mitral anular calcific deposits and in the absence of diffuse disease of the mitral leaflets has not been demonstrated previously. The diastolic gradients are considered to result from the combination of the large mitral anular calcific deposits and the small, thick-walled, noncompliant left ventricles.

Group teaching of auscultation. Use of a new wireless stethoscope-type headphone.

A new technique using infrared light for the transmission of heart sounds and murmurs is described. This method enables the simultaneous transmission of heart sounds and murmurs to large groups of persons without the need for hard-wire connections to the amplifying device. The method facilitates teaching of cardiac auscultation at the bedside as well as in the setting of conferences, seminars or postgraduate education programs.

Paradoxical motion of the interventricular septum in a patient with normal right heart hemodynamics.

A 32-year-old man with paradoxical motion of the interventricular septum at the level of the chordae tendineae and with normal right heart hemodynamics is presented. It appears that, in absence of severe left ventricular dysfunction or intraventricular conduction defect, paradoxical septal motion is not entirely specific for right ventricular volume overload and may represent a rare normal variant.

Ultrasonography: its usefulness and reliability in early pregnancy. A review of 210 cases.

A total of 210 women who had ultrasonic examination done during early pregnancy, and whose final pregnancy outcome was known, were reviewed to assess the usefulness and reliability of the procedure. Ultrasonography was found to be diagnostic in 96.2 per cent of these cases, with the primary indication for its use being "assessment of pregnancy wellbeing." Multiple gestations, hydatidiform moles, and pelvic tumors associated with pregnancy were readily diagnosed and assessed in their early stages and the gestational age was correctly determined when dates were uncertain.

Ultrasonic cephalometry: Its use in estimating fetal weight.

Data on 100 consecutive patients delivering within 1 week after ultrasonic cephalometry measurement were reviewed to assess the weight-predicting potential of three known formulas. With Thompson's formula, 78% of infant weights fell within a range of 350 g, the absolute mean error for the 100 cases being 267 g. Excluding cases of fetal malnutrition, when the biparietal diameter (BPD) obtained was 8.3 cm or more, all newborn babies weighed more than 2000 g, and with a BPD of 8.7 cm or more they all exceeded 2500 g. Ninety percent of newborn babies in whom the in utero BPD was 9.1 cm or more weighed more than 3000 g. These values compared very favorably with those from other series and, thus, demonstrate the usefulness of this type of assessment.