Occurrence and seasonal incidence of mosquitoes on Indian reservations in Iowa, Nebraska and South Dakota during 1983

A mosquito surveillance program designed to prevent future human cases of Western equine encephalitis or Saint Louis encephalitis was established in 1983 on Indian reservations under the jurisdiction of the Aberdeen Area Indian Health Service in Iowa, Nebraska and South Dakota. Standard New Jersey light traps were operated on all reservations throughout the summer season while CDC miniature and encephalitis virus surveillance traps were employed for shorter periods of time on 4 reservations. Aedes vexans was the most abundant species except on the Pine Ridge, Rosebud, Winnebago and Yankton Sioux reservations in which Culex tarsalis predominated and for the Sac-n-Fox where Aedes trivittatus occurred with the greatest frequency.     

Traumatic intratemporal facial nerve injury: management rationale for preservation of function

A retrospective review of 29 cases of intratemporal facial nerve injuries included 18 temporal bone fractures, 7 gunshot wounds, and 4 iatrogenic complications. Surgical exploration confirmed involvement of the fallopian canal in the perigeniculate region in 14 longitudinal and 3 transverse or mixed fractures of the petrous pyramid. Gunshot and iatrogenic injuries usually occurred within the tympanic and vertical segments of the facial canal and at the stylomastoid foramen. When hearing is salvageable, the middle fossa approach provides the best access to the perigeniculate region of the facial nerve. In the presence of severe sensorineural hearing loss, the transmastoid-translabyrinthine approach is the most appropriate for total facial nerve exploration. Grade I to III results can be anticipated in timely decompression of lesions caused by edema or intraneural hemorrhage. Undetectable at the time of surgery, stretch and compression injuries with disruption of the endoneural tubules often lead to suboptimal results. Moderate-to-severe dysfunction (Grade IV), with slight weakness and synkinesis, is the outcome to be expected from the use of interpositional grafts.     

Failure of nitric oxide donors to alter arrhythmias induced by acute myocardial ischaemia or reperfusion in anaesthetized rats.

1. The aim of the present studies was to examine the effects of nitric oxide donors on arrhythmias induced by coronary artery occlusion and reperfusion, and on cardiac cyclic nucleotides. Experiments were performed in pentobarbitone-anaesthetized rats prepared for occlusion of the left coronary artery. 2. Sodium nitroprusside (0.1, 0.3 and 1 microgram kg-1 min-1) had no significant effects on the incidence of ventricular tachycardia, total ventricular fibrillation or the mortality resulting from 25 min of acute myocardial ischaemia when compared with values in controls. In addition, there was no alteration in the number of ventricular premature beats that occurred in survivors. 3. 3-Morpholinosydnonimine-N-ethylcarbamide (SIN-1, 10, 20 and 40 micrograms kg-1 min-1) caused marked hypotension but did not alter the incidence or severity of ischaemia-induced arrhythmias. In rats subject to abrupt reperfusion after 5 min of myocardial ischaemia, lower doses of SIN-1 (1, 3 and 10 micrograms kg-1 min-1) still caused significant reductions in systolic and diastolic blood pressure but were devoid of antiarrhythmic activity. 4. In separate experiments in sham-operated rats, sodium nitroprusside (1 microgram kg-1 min-1), isosorbide dinitrate (30 and 60 micrograms kg-1 min-1) and SIN-1 (20 and 40 micrograms kg-1 min-1) had no significant effects on cardiac cyclic GMP content. 5. These results indicate that nitric oxide donors do not alter arrhythmias induced by acute coronary artery occlusion or reperfusion in anaesthetized rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aspartylglucosaminuria in the United States

Aspartylglucosaminuria (AGU) was diagnosed in two unrelated males with progressive mental retardation, coarse facies and skeletal abnormalities. Until now, this disorder has been described in predominantly Finnish populations with only one previous case reported in the U.S. We conclude that AGU may be more common in nowFinnish populations than the number of reported cases would indicate and should be included in the differential diagnosis in patients with suspected lysosomal storage disorders regardless of their geographical or ethnic backgrounds.     

Comparison of the acute cardiotoxicity of the antimalarial drug halofantrine in vitro and in vivo in anaesthetized guinea-pigs

1. Several unrelated drugs have pro-arrhythmic activity associated with an ability to prolong the QT interval of the ECG. The aim of this work was to examine the effects of the antimalarial drug halofantrine in vivo and in vitro.
2. In anaesthetized guinea-pigs consecutive bolus doses of halofantrine (0.3, 1, 3, 10 and 30 mg kg⁻¹, i.v.) at 25 min intervals caused dose-dependent prolongation of the rate corrected QTc interval and bradycardia. The change in heart rate became significant after administration of 10 mg kg⁻¹ halofantrine (−23±9 beats min⁻¹) whereas the increase in QTc was significant with only 1 mg kg⁻¹ halofantrine (22±10 ms). It was only with the highest dose of halofantrine that the PR interval was increased (from 52±3 to 67±4 ms) and second degree atrioventricular (AV) block (type 1 Mobitz) occurred in all animals. No changes were observed in any parameters in a separate group of guinea-pigs which received vehicle (dimethylacetamide 60% propylene glycol 40%) at equivalent time points.
3. The blood concentrations of halofantrine ranged from 0.26±0.17 μM after administration of 0.3 mg kg⁻¹ to 2.79±0.87 μM after 30 mg kg⁻¹, i.v. There was a significant correlation between the blood concentrations of halofantrine and the changes in QTc interval.
4. In guinea-pig left papillary muscles the effective refractory period was increased significantly 60 min after addition of halofantrine; from 161±4 to 173±6 ms with 10 μM, 156±8 to 174±6 ms with 30 μM and 165±6 to 179±5 ms with 100 μM halofantrine. However, the vehicle (0.1% Tween 80 in DMSO; final concentration of vehicle in Krebs, 1%) also increased the effective refractory period from 164±5 to 173±6 ms. Similar results were obtained in right ventricular strips but left atrial effective refractory periods were not altered by either the vehicle or halofantrine.
5. The results of these experiments suggest that any direct effects that halofantrine may have had on the effective refractory period of cardiac muscle cannot be separated from those of the vehicle. The prolongation of QTc and consistent observation of AV block with halofantrine in anaesthetized guinea-pigs suggest that in vivo models may be more useful for further studies investigating the mechanisms underlying the cardiotoxicity of halofantrine.

     

Macular disease and optical coherence tomography

Optical coherence tomography (OCT) is a new diagnostic tool for high-resolution cross-sectional imaging of the retina. By measuring the "echo" delay time of light as it reflects from tissue at different ranges and by performing multiple axial scans in the transverse direction, OCT generates two-dimensional images detailing retinal architecture. OCT is a powerful new modality because it has a longitudinal resolution of 10 microns in the retina, which is superior to other currently available imaging techniques. Examinations are exceptionally tolerable for patients because OCT is noninvasive, the probe beam is near-infrared and thus not very bright, and scan acquisition time is only 2.5 seconds. OCT appears to be a useful device for evaluating a variety of retinal diseases, including macular holes, macular edema, and central serous chorioretinopathy.