[Elevation of serum lactate dehydrogenase. Diagnostic, prognostic and evolutive values]. / Elévation des lactates-déshydrogénases sériques. Valeur diagnostique, pronostique et évolutive.

OBJECTIVE: Determination of serum lactate dehydrogenase (LDH) levels is an usual practice. However, its place in the diagnosis process is not clear. We have collected serum LDH levels superior to 2-fold the normal rate and we tried to determine their diagnostics interest and, predictive and progressive values. METHODS: Retrospective study during 3 months in hospitalized adults. LDH levels were measured by spectrophotometry (Normal rate: 313-618 UI/L). RESULTS: 196 cases with LDH level elevations higher than 1236 UI/L were analyzed. The etiology of LDH level elevations were was benign in 60% of cases, malignant in 36% and, undetermined in 5%. There was no difference in between average values of LDH level average values of benign and malignant etiology (2708 vs 2842 UI/l). LDH rates and high LDH level elevations were not helpful for in the diagnosis process (a variety of 43 etiology was able to elevate increased LDH rates). In 45% cases, LDH level was 2 to 3-fold the normal rate; in 47.5% cases, 3 to 10-fold normal rate, and in 7.5% cases, superior to 10-fold normal rate. LDH elevations superior to 10-fold the normal rate were caused by benign etiology in 11 cases and malignant disease in 4 cases. A level superior to 10-fold the normal rate was not helpful in determining to determine the benign or malignant characteristics of the initial disease. However, LDH rate superior to 10 normal rate was a pejorative predictive criteria (hospitalization in intensive careunity in 73% of cases and mortality rate of 53%). During follow up of a neoplasia or malignant hemopathy follow up, several LDH measurements LDH level determinations were determined in for a small number of patients. LDH level normalizations is are attributable to efficientan effective treatment; LDH level elevations are associated with a therapeutic failure echappment. Evolution in LDH levels evolution was influenced by progression in neoplasia and malignant hemopathy evolution and also by various several treatments such as like blood transfusions, growth factors, radiotherapy and chemotherapy. CONCLUSION: LDH level elevation, however whatever its rate, don't seem to do not help in differentiating have interest to differentiate benign from malignant diseases. However, an elevation LDH elevation higher than 10-fold the normal rate is a pejorative predictive criteria, since because the mortality rate is superior toupper than 50%. During follow-up of in the neoplasia and malignant hemopathy follow up, so long as they are measured at distance from treatment, variations in LDH levels are a good marker of evolution, rate variations represent an evolutive marker conditionally the level determination would be realize remote several treatment.

Microhabitat-independent regional differences in survival of unfed Ixodes scapularis nymphs (Acari:Ixodidae) in Connecticut.

The effects of habitat and microclimate on survival of unfed nymphal black-legged ticks, Ixodes scapularis Say (approximately I. damnini Spielman, Clifford, Piesman & Corwin), were studied under natural conditions in southcentral and northwestern Connecticut. At both coastal and inland locations, survival of 3 groups of 20 wild-caught questing nymphs placed in nylon mesh bags was monitored in each of 3 different habitats (field, forest canopy, and forest/field edge) during summer 1995. Simultaneously, soil temperature, ground-level air temperature, and relative humidity were measured continuously within each habitat at both sites. The number of ticks surviving in each habitat was monitored weekly. Average daily survival rates of nymphs were related inversely to soil temperature but were not related to air temperature or humidity. Overall, nymphal ticks at the inland site survived significantly longer than those at the coastal site; however, no significant differences in mortality rates were found among habitats. These results suggest that inland environmental conditions are suitable for lengthy survival of unfed nymphal I. scapularis in regions where this tick is not yet abundant.

Microclimate-dependent survival of unfed adult Ixodes scapularis (Acari:Ixodidae) in nature: life cycle and study design implications.

Microclimate and other abiotic factors may be important in determining the survival of arthropod vectors, yet the impact of such variables rarely has received careful examination. The impacts of habitat, microclimate, and experimental confinement on survival rates of unfed adult blacklegged ticks, Ixodes scapularis Say, were studied in field enclosures in southcentral and northwestern Connecticut. At both locations, 2 enclosures were placed in each of 3 different habitats (field, forest canopy, and forest/field edge). Forty wild-caught adult ticks (20 males, 20 females) were placed in each enclosure. At one site, another 40 ticks were confined to nylon mesh bags placed inside each enclosure. Soil temperature, ground-level air temperature and relative humidity were measured within each habitat. The number of ticks surviving within each enclosure was monitored 1 or 2 times per week. Ticks that were confined in nylon bags had a lower survival rate than ticks that were able to move freely within the enclosures. Ticks survived longer in edge and forest habitats than in open fields, which were characterized by greater extremes in air temperature, soil temperature, relative humidity, and vapor pressure deficit than the other 2 habitats. The mean daily survival rates of free-ranging I. scapularis were negatively related to air temperature, vapor pressure deficit, and the coefficient of variation of relative humidity.