[Perspectives on resilience : trait or aptitude ?]

In this paper, we discuss various issues related to the concept of resilience, which is conventionally defined as a dynamic process allowing for a positive adaptation in a context of significant adversity. First, we try to draw the reader's attention to the importance of the concept of resilience in terms of public health. Second, we address the difficulty of measuring resilience in a relevant and operational manner. Third, we then address the question of whether resilience can be conceived only in the context of a confrontation with trauma, or whether its application can be relevant to the everyday nontraumatic adversity. In this regard, we introduce and define another coping strategy which is the Sense of Coherence (SOC). Fourth, we discuss the nature of resilience, that is to say, whether it should be considered as a personality trait or as an aptitude. We try to show that this problem arises from the difficulty to specify the emotional processes involved in resilience. Finally, we propose future research perspectives that should allow us to better understand the concept of resilience.

Iothalamate clearance and its use in large-scale clinical trials

Several recently completed or ongoing large-scale clinical trials, including the Modification of Diet in Renal Disease Study, the Diabetes Control and Complications Trial, and the African-American Study of Kidney Disease and Hypertension, have all chosen the renal clearance of sodium 125I-iothalmate to monitor renal disease progression. The need for accurate and precise renal testing at multiple clinical sites, with centralized renal sample processing, clearly exceeds the limited scope of most other glomerular filtration rate methods. Analysis of 3580 studies combined from the Modification of Diet in Renal Disease Study and Diabetes Control and Complications Trial demonstrates that trained clinical personnel can successfully perform the 125I-iothalamate clearance glomerular filtration rate method in large-scale studies. Overall, intratest and interest glomerular filtration rate coefficients of variation of approximately 10 and 6% are acceptable for such studies. Strict standardization of glomerular filtration rate protocol with respect to water loading, equilibration time after injection, and pre-study fasting is of crucial importance. Other confounding phenomena, including regression to the mean of progression slopes, must be considered before renal results of an intervention can be assessed. The 125I-iothalamate clearance glomerular filtration rate method offers good accuracy and precision, reasonable clinical convenience, straightforward and efficient central laboratory analysis, and reasonable cost and safety for large-scale clinical trials.

Renal effects of multiple infusion of pyridoxalated-hemoglobin-polyoxyethylene conjugate (PHP) solution in dogs

Pyridoxalated-hemoglobin-polyoxyethylene conjugate (PHP), which is made from out-dated human red blood cells by two major chemical modifications, namely pyridoxalation and conjugation with polyoxyethylene (POE), is currently under development as a physiological oxygen carrier. This study assessed the effects of PHP-88 solution, which contains 8% (wt/vol) each of hemoglobin (Hb) and maltose, on renal function when it was infused 3 times every other day into the intact circulation of 8 dogs (5 dogs for the PHP group and 3 for the control group; 20 ml/kg for the first infusion, and 10 ml/kg each for the second and third infusions, at the rate of 2.5 ml/h/kg). Serial determinations of glomerular filtration rate (GFR) and renal plasma flow (RPF) were carried out pre- and postinfusion for up to 3 months along with measurements of blood and urine analyses, urine output rate, fractional excretion of sodium (FES), and free water clearance (CH2O). The results showed that plasma colloid osmotic pressure (COP) elevated an average of 3.3 mm Hg (p = 0.0085), and GFR and RPF tended to increase by 13% (NS) and 38% (NS), respectively, immediately after the third infusion with PHP solution. Urine output rate increased during and after the infusion, and FES and CH2O also increased for 24 h after the infusion in both groups. Blood urea nitrogen, serum creatinine, and serum Na+ concentrations were not affected greatly by the infusions, but hematocrit was decreased by 8% in the PHP group, indicating approximately a 42% expansion of plasma volume. These changes were observed to return to their preinfusion levels by 1 week postinfusion. Renal histology of the PHP group obtained at 2 weeks postinfusion revealed vacuole formation in the proximal tubules which was not associated with any pathologic changes indicative of cell death or regeneration. In 4 out of 5 dogs at 3 months postinfusion (necropsy), the vacuoles were not present. Though urinary N-acetyl-beta-glucosaminidase (NAG) activity had significantly increased after infusion, it returned to the preinfusion level by 1 month postinfusion. No detrimental effect of vacuoles on the assessed renal tubular functions was confirmed in the present study. The results demonstrated that multiple infusions of PHP solutions were well tolerated in normal dogs, and the observed effects were conceived predominantly attributable to the physiological response of the kidneys to an oncotic load into the circulation, which produced plasma volume expansion.

Effects of single-dose infusion of pyridoxalated-hemoglobin-polyoxyethylene conjugate solution on canine renal function

Pyridoxalated-hemoglobin-polyoxyethylene conjugate (PHP) is an acellular oxygen-carrying red blood cell substitute made from outdated human red blood cells. This study assessed the effect of PHP on renal function when PHP was infused with a clinically relevant dosage. A single dose of PHP that contains 8% wt/vol each of hemoglobin and maltose or an 8% maltose control solution was infused into the intact circulation of eight dogs (five dogs for PHP and three for the control; 20 ml/kg each, at the rate of 2.5 ml/h/kg for 8 h) in the awake state. Serial measurements of glomerular filtration rate (GFR) and renal plasma flow (RPF) were carried out before and after infusion for up to 2 weeks, along with determinations of urine volume flow rate, fractional excretion of sodium (FES), and free water clearance (CH2O). The results showed an elevation of plasma colloid osmotic pressure by an average of 4.4 mm Hg immediately postinfusion with PHP solution. An average 23% decrease in GFR, without notable changes in RPF immediately postinfusion, was observed in the PHP group; the value returned to the preinfusion level by 1 week postinfusion. Increases in parameters such as urine output, FES, and CH2O, which were more pronounced in the PHP group, were observed for 24 h after the infusion in both groups. Light microscopic examination of kidney specimens taken at 2 weeks postinfusion revealed a slight degree of vacuole formation in approximately 80% of the proximal tubules in the PHP group. The tubules were devoid of typical pathologic features of acute renal failure, and the vacuoles did not cause any observable changes in the assessed tubular functions.

[Where lies the boundary between common sensation and taste perception in electrogustometry (author's transl)]

The shift of the electrogustatory threshold following section of the corda tympani has been investigated in 14 patients. Postoperatively the anterior half of the tongue showed complete ageusia. Two thirds of the patients were able to recognize stimulations of 50-127 muA as a burning, and not a sour metallic, sensation for at least 1-2 weeks. Probably the trigeminal nerve endings perceive this burning sensation during the period of taste bud degeneration. A similar situation exists in cases where the gustatory fibres are interrupted proximal to the gustatory ganglion, because the tasts buds do not degenerate. It is therefore important to ask the patient to describe the sensation experienced. Only a sour metallic taste during electrogustometry should be regarded as a true gustatory sensation.