Blur adaptation: clinical and refractive considerations

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.     

Organization of the trigeminal and facial motor nuclei in the hagfish, Eptatretus burgeri: a retrograde HRP study

We studied the trigeminal and facial motor nuclei of the hagfish by the retrograde HRP method. We distinguished 4 components in a single column of the motor nuclei of the trigeminal nerve and the facial nerve, viz., the pars magnocellularis of the trigeminal motor nucleus (mVm), the anterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp1), the posterior part of the pars parvocellularis of the trigeminal motor nucleus (mVp2) and the facial motor nucleus (mVII). Although in Nissl preparations only the mVm could be distinguished from the rest of the nucleus, the boundaries of the other 3 components were clearly demarcated in HRP preparations. Intramuscular injections into two representative antagonistic jaw muscles revealed that there was no apparent topological organization of the neurons pertaining to the opening and closing muscles in the mVm and mVp1, but both antagonistic muscles were innervated bilaterally. Although the hagfish does possess a cartilaginous jaw, the organization pattern of the motor nuclei of the jaw muscles seems to be the most primitive of all living vertebrates.     

Rupture of the supradiaphragmatic inferior vena cava by blunt decelerating trauma: case report

Lacerations of the inferior vena cava resulting from blunt external trauma are relatively rare, but extremely serious. The high lethality is due to the difficulty in diagnosis and technical problems with repair, particularly if the injury is located above the renal veins. During a 12-month period seven patients with inferior vena cava laceration were seen, of whom two presented with laceration of the inferior vena cava above the diaphragm. Both had a deceleration injury while wearing seatbelts. The clinical presentation was similar. The etiology is discussed. Caval continuity should be repaired because acute sudden occlusion at the suprahepatic level is incompatible with survival. Median sternotomy is advised, moreover it provides good exposure for eventual cannulation.     

Parathyroid imaging. Use of dual isotope scintigraphy for the localization of adenomas before surgery.

Seventy-nine patients with primary hyperparathyroidism, whose average preoperative blood calcium level was 11.6 mg/dl, underwent thallium-technetium dual isotope scintigraphy of the thyroid and parathyroids. For patients who had surgery, the detection and localization rate of parathyroid disease or the sensitivity was low (0.53), but the positive predictive value for the location was high (0.80). Correct localization correlated positively with the weight of the tumor but not significantly with the parathyroid hormone blood level nor with the blood calcium level. Unprocessed data alone were sufficient to predict correctly the location in two thirds of the detected cases. Computer processing increased the sensitivity without decreasing the specificity. Those results, at variance with earlier published data but congruent with another more recent study, require a reevaluation of the role of this scintigraphic technique in the management of hyperparathyroidal patients.     

Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients

High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.      

Whole-body inflammation in trauma patients. An autopsy study

In a review of autopsy specimens and reports in 35 trauma cases, we found signs of generalized inflammation and tissue damage with increases in organ weights in organs not primarily injured. These abnormalities occurred independent of the time of death and were also found in patients who died of brain injury alone. The most pronounced signs of inflammation and increases in organ weights were found when the adult respiratory distress syndrome, hypovolemic shock, or multiple organ failure were the causes of death. These findings are similar to those found in several organs of rabbits after four hours of complement activation in combination with 20 minutes of hypoxia. Therefore, the autopsy findings in this series of trauma patients might represent the morphologic features of adult respiratory distress syndrome and multiple organ failure in an early, preclinical stage.