Demographical and clinical indices for long-term evolution of patients in vegetative or in minimally conscious state.

Objective. To evaluate the prognostic value of demographical, anamnestic, and clinical findings on long-term outcome (up to 36 months) in individuals with severe brain injury in vegetative state (VS) or in minimally conscious state (MCS).Participants. Patients (N = 216) in VS (N = 159) or in MCS (N = 57) consecutively admitted to a neurorehabilitation unit within 1-3 months after severe anoxic (n = 71), vascular (n = 96), or traumatic (n = 49) brain injury.Main outcome. Mortality and improvements in clinical diagnosis at 12, 24, and 36 months after brain injury. Multivariable logistic regression analyses were performed to verify independent relationships of variables collected at study entry with outcome measures.Results. In patients in VS, at the 12-month follow-up, higher level of responsiveness assessed by the Coma Recovery Scale-Revised (CRS-R) total scores at study entry predicted a higher likelihood of both survival and clinical improvement, whereas younger age predicted survival only. At 24 months, female sex and higher CRS-R total scores tended to be associated with clinical improvements. In patients in MCS, younger age and female predicted consciousness recovery at 12 months.Conclusions. Several patients' features easy to collect in rehabilitation setting might help clinicians in prognostication of long-term mortality and clinical evolution of VS and MCS.

Psychological distress is associated with altered cognitive functioning in family caregivers of patients with disorders of consciousness.

OBJECTIVES: To analyse the possible presence of reduced cognitive efficiency in family caregivers of patients with prolonged disorders of consciousness (DOC). SUBJECTS: The participants were 27 caregivers of 25 patients with DOC admitted to the severe brain injury units of the ICS Maugeri, Institutes of Telese Terme and Sciacca, Italy. METHODS: We examined cognitive functions such as short- and long-term memory, executive functions and attention by means of standardized tests. We also assessed features of psychological distress such as anxiety, depression, psychophysiological symptoms, prolonged grief disorder, psychological burden and quality of life. All scores on neuropsychological tests were compared with those of the 15 matched control subjects. RESULTS: Enrolled family caregivers showed high frequency of clinically relevant depressive symptoms and anxiety; half of them met the criteria for prolonged grief disorder. Caregivers achieved scores lower than the matched controls on tests for selective attention, verbal fluency and long-term spatial memory. CONCLUSIONS: Family caregivers' burden is associated with a reduced efficiency of selected executive measures and visuospatial learning. These results emphasize the need for appropriate psychological and cognitive supporting therapies for family caregivers of patients with DOC, also considering their delicate involvement in clinical decision-making and in providing care.

ITS2 as a molecular marker for the identification of Diatraea saccharalis and D. flavipennella and possible infection with Cotesia spp.

In Brazil, the species Diatraea flavipennella and D. saccharalis play an important role in the sugar and alcohol agribusiness by causing many damages in sugarcane fields. The egg, larva, pupa, and adult stages are very morphologically similar between these species, and the identification can be confused. The internal transcribed spacer 2 (ITS 2) from ribosomal DNA has important features as evolutionary divergence. It is a good marker for species identification, participates in the rDNA processing, and has been applied in phylogenetic and population studies. This study aimed to make available a molecular marker to assist on the identification method of pests' species of Diatraea and to identify possible traces of Cotesia in the resistant host. The DNA was extracted from the egg, larva, and adult samples. PCR amplicons were purified and sequenced. The sequences were analyzed in MEGA 5.01. The ITS 2 length was 410 bp in D. flavipennella and 448 bp in D. saccharalis. The GC content was similar between the species. Three microsatellite loci were present in D. saccharalis and absent in D. flavipennella, contributing to differences in ITS 2 length in the species. An additional 367-bp band was attributed to Cotesia spp. The differences among ITS 2 from D. flavipennella, D. saccharalis, and Cotesia sp were sufficient to identify them on electrophoresis gel and sequencing. The presence of Cotesia sp traits in adult D. flavipennella showed possible host refractoriness, but further studies are necessary.

U1 snDNA clusters in grasshoppers: chromosomal dynamics and genomic organization.

The spliceosome, constituted by a protein set associated with small nuclear RNA (snRNA), is responsible for mRNA maturation through intron removal. Among snRNA genes, U1 is generally a conserved repetitive sequence. To unveil the chromosomal/genomic dynamics of this multigene family in grasshoppers, we mapped U1 genes by fluorescence in situ hybridization in 70 species belonging to the families Proscopiidae, Pyrgomorphidae, Ommexechidae, Romaleidae and Acrididae. Evident clusters were observed in all species, indicating that, at least, some U1 repeats are tandemly arrayed. High conservation was observed in the first four families, with most species carrying a single U1 cluster, frequently located in the third or fourth longest autosome. By contrast, extensive variation was observed among Acrididae, from a single chromosome pair carrying U1 to all chromosome pairs carrying it, with occasional occurrence of two or more clusters in the same chromosome. DNA sequence analysis in Eyprepocnemis plorans (species carrying U1 clusters on seven different chromosome pairs) and Locusta migratoria (carrying U1 in a single chromosome pair) supported the coexistence of functional and pseudogenic lineages. One of these pseudogenic lineages was truncated in the same nucleotide position in both species, suggesting that it was present in a common ancestor to both species. At least in E. plorans, this U1 snDNA pseudogenic lineage was associated with 5S rDNA and short interspersed elements (SINE)-like mobile elements. Given that we conclude in grasshoppers that the U1 snDNA had evolved under the birth-and-death model and that its intragenomic spread might be related with mobile elements.

Physical mapping of 18S and 5S rDNA loci and histone H3 gene in grasshopper species of the subfamily Gomphocerinae (Acrididae).

In this study, fluorescence in situ hybridization (FISH) analysis was used to determine and compare the numbers and chromosomal locations of two multigene families (rDNA and histone H3) in four Neotropical species of gomphocerine grasshoppers. FISH using the 18S rDNA probe identified a single site on the S9 chromosome of Amblytropidia sp and Cauratettix borelli, a single site on chromosome M6 of Compsacris pulcher, and two sites (chromosomes L1 and L2) in Orphulella punctata. By contrast, FISH with a 5S rDNA probe identified dispersion of this sequence in the genomes of the four species, with evidence of intraspecific variations. Amblytropidia sp had six to eight FISH signals on autosomal chromosomes, while C. pulcher exhibited a signal only on the M5 bivalent. The histone H3 gene was less variable and was restricted to a single pair in all species. The conservation of the numbers and locations of 18S rDNA and H3 genes in conjunction with data from the literature was useful for evaluating karyotype evolution in this subfamily. The variation in the number and sizes of 5S rDNA sites indicates a process of recent dispersion that might have been mediated by transposition.

Short Communication A small B chromosome in the grasshopper Ommexecha virens (Ommexechidae).

B chromosomes, also called supernumerary or accessory chromosomes, have been characterized as extra elements found in the karyotypes of different eukaryotic species. B chromosomes are nonvital and only occur in some individuals within a species. Moreover, the chromosomes contain silenced genes, and they exhibit heterochromatinization and the accumulation of repetitive DNA and transposons. In the present study, we describe an extra chromosome in the grasshopper Ommexecha virens for the first time, using conventional staining and fluorescent in situ hybridization techniques, and we discuss the possible origin of the B chromosome.

Sequential treatment with monofluorophosphate and zoledronic acid in osteoporotic rats.

OBJECTIVE: Osteoporosis is the consequence of an imbalance in bone remodeling caused by excessive resorption or inappropriate bone formation. This paper proposes a sequential treatment with monofluorophosphate (MFP) and zoledronic acid (Z), together with changes in the calcium content in the diet. METHOD: Seven-week-old female Sprague Dawley rats were divided into five groups (n = 21 per group): (1) sham-operated rats (Sham); (2) ovariectomized (OVX) rats fed with a normal calcium diet (OVX); (3) OVX rats fed with a normal calcium diet and treated sequentially with monofluorophosphate and zoledronic acid (OVX.G1); (4) OVX rats sequentially fed with a low calcium diet and then a high calcium diet, without treatment (OVX.G2); (5): OVX rats fed with a low calcium diet and then a high calcium diet, treated sequentially with monofluorophosphate and zoledronic acid (OVX.G3). RESULTS: After 150 days, the OVX.G3 group showed a similar bone volume to that of the Sham group due to an increase in trabecular number. Dual X-ray absorptiometry bone analysis showed an increase of 9.8% compared with OVX rats. Additionally, an increase in the fracture load at the cortical bone and higher fracture load, ultimate load and stiffness in the compression test were found. CONCLUSION: The sequential treatment with monofluorophosphate and zoledronic acid increases trabecular bone mass, bone mineral density and bone strength.

B chromosome prevalence and physical mapping of 18S rDNA and H4 histone sites in the grasshopper Xyleus discoideus angulatus (Romaleidae).

We sampled 11 natural populations of the grasshopper Xyleus discoideus angulatus in Northeastern Brazil to analyze B chromosome frequency and meiotic behavior. We observed a single large B chromosome, resembling the X chromosome, in 29 of the 402 specimens. Eight of the 11 populations had B chromosomes, with a rather broad geographical distribution, suggesting that this is an ancient polymorphism; significant differences were observed in B chromosome prevalence among the populations. Presence of the B chromosome was associated with increased frequency of macrospermatids. Fluorescent in situ hybridization revealed 18S rDNA sites in the pericentromeric regions of the X and L3 chromosomes, although some populations had an additional locus on the M4 chromosome. No variation was found for chromosome location of H4 histone genes, which were always observed in paracentromeric regions of the L2, M4 and X chromosomes, a rather unusual location compared to locations known from the families Acrididae and Proscopiidae. These B chromosomes lacked these two kinds of repetitive DNA, at least in amounts that can be visualized by fluorescent in situ hybridization, suggesting that these B chromosomes did not originate from any of the four chromosomes carrying rDNA or H4 histone genes.

Relieving your stress: PGPB associated with Andean xerophytic plants are most abundant and active on the most extreme slopes.

Introduction: Plants interact with plant growth-promoting bacteria (PGPB), especially under stress condition in natural and agricultural systems. Although a potentially beneficial microbiome has been found associated to plants from alpine systems, this plant- PGPB interaction has been scarcely studied. Nevados de Chillán Complex hold one of the southernmost xerophytic formations in Chile. Plant species living there have to cope with drought and extreme temperatures during the growing season period, microclimatic conditions that become harsher on equatorial than polar slopes, and where the interaction with PGPB could be key for plant survival. Our goal was to study the abundance and activity of different PGPB associated to two abundant plant species of Andean xerophytic formations on contrasting slopes. Methods: Twenty individuals of Berberis empetrifolia and Azorella prolifera shrubs were selected growing on a north and south slope nearby Las Fumarolas, at 2,050 m elevation. On each slope, microclimate based on temperature and moisture conditions were monitored throughout the growing period (oct. - apr.). Chemical properties of the soil under plant species canopies were also characterized. Bacterial abundance was measured as Log CFU g-1 from soil samples collected from each individual and slope. Then, the most abundant bacterial colonies were selected, and different hormonal (indoleacetic acid) and enzymatic (nitrogenase, phosphatase, ACC-deaminase) mechanisms that promote plant growth were assessed and measured. Results and Discussion: Extreme temperatures were observed in the north facing slope, recording the hottest days (41 vs. 36°C) and coldest nights (-9.9 vs. 6.6°C). Moreover, air and soil moisture were lower on north than on south slope, especially late in the growing season. We found that bacterial abundance was higher in soils on north than on south slope but only under B. empetrifolia canopy. Moreover, the activity of plant growth-promoting mechanisms varied between slopes, being on average higher on north than on south slope, but with plant species-dependent trends. Our work showed how the environmental heterogeneity at microscale in alpine systems (slope and plant species identity) underlies variations in the abundance and plant growth promoting activity of the microorganisms present under the plant canopy of the Andean xerophytic formations and highlight the importance of PGPB from harsh systems as biotechnological tools for restoration.

Use baseline axial length measurements in myopic patients to predict the control of myopia with and without atropine 0.01.

PURPOSE: Identifying axial length growth rate as an indicator of fast progression before initiating atropine 0.01% for myopia progression in children. METHOD: From baseline, axial length growth over six months was measured prospectively. Subjects were then initiated on atropine 0.01% if axial length growth was greater than 0.1mm per 6 months (fast progressors), axial length and spherical equivalent change measurements recorded every six months. The rate of change was compared to the baseline pre-treatment rate. If axial length change was below the threshold, subjects received monitoring only. RESULTS: 73 subjects were identified as fast progressors and commenced atropine 0.01%, (mean baseline refraction of OD -2.9±1.6, OS -2.9±1.8 and a mean baseline axial length OD 24.62 ± 1.00 mm, OS 24.53 ± 0.99 mm). At six months, the mean paired difference of axial length growth rate was significantly reduced by 50% of baseline (all 73 subjects, p<0.05). 53 subjects followed to 12 months, and 12 to 24 months maintained a reduced growth rate. Change in mean spherical equivalent was significantly reduced compared to pre-treatment refractive error (mean paired difference p<0.05) and at each subsequent visit. 91 children were slow progressors and remained untreated. Their axial length growth rate did not change significantly out to 24 months. Spherical equivalent changed less than -0.5D annually in this group. CONCLUSION: Identifying fast progressors before treatment initiation demonstrated a strong treatment effect with atropine 0.01% reducing their individual rate of myopia progression by 50%. Another large group of myopic children, slow progressors, continued without medical intervention. A baseline axial length growth rate is proposed as a guideline to identify fast progressors who are more likely to benefit from atropine 0.01%.

Observing brownian motion in vibration-fluidized granular matter.

Observation of the rotational brownian motion of a very fine wire immersed in a gas led to one of the most important ideas of equilibrium statistical mechanics. Namely, the many-particle problem of a large number of molecules colliding with the wire can be represented by just two macroscopic parameters: viscosity and temperature. Interest has arisen in the question of whether this idea (mathematically developed in the Langevin model and the fluctuation-dissipation theorem) can also be used to describe systems that are far from equilibrium. Here we report an experimental investigation of an archetypal non-equilibrium system, involving a sensitive torsion oscillator immersed in a granular system of millimetre-size grains that are fluidized by strong external vibrations. The vibro-fluidized granular medium is a driven environment, with continuous injection and dissipation of energy, and the immersed oscillator can be seen as analogous to an elastically bound brownian particle. By measuring the noise and the susceptibility, we show that the experiment can be treated (to a first approximation) with the equilibrium formalism. This gives experimental access to a granular viscosity and an effective temperature; however, these quantities are anisotropic and inhomogeneous. Surprisingly, the vibro-fluidized granular matter behaves as a 'thermal' bath satisfying a fluctuation-dissipation relation.

Ophthalmologic presentation of oxidative phosphorylation diseases of childhood.

To investigate ophthalmologic manifestations in children with definitive oxidative phosphorylation disorders, a retrospective review was conducted of clinical and laboratory records of all such pediatric patients (n = 103) diagnosed and treated at one center between 1983 and 2006. All were residents of Victoria, Australia. Nystagmus or roving eye movements were the most common ophthalmologic manifestations as a presenting symptom of disease (13/20) and were the sole manifestation at presentation in 10/13 patients. Divergent strabismus was a presenting symptom in 5/20 patients and was the sole manifestation at presentation in 3/20 patients. Abnormal eye movements were noted in 6 patients and strabismus was noted in 4 patients with Leigh's or Leigh-like disease; in 9 of these 10 patients, Leigh's disease was the result of complex I deficiency. Altogether, ophthalmologic manifestations were noted at presentation in 12/35 patients with complex I deficiency. External ophthalmoplegia in conjunction with ptosis was the presenting symptom in 3/20 patients, all with Kearns-Sayers syndrome. Patients suspected of having oxidative phosphorylation disorders should be referred for ophthalmologic examination. Prospective studies are needed for a comprehensive elucidation of the ophthalmologic findings in these disorders.

Effect of disodium monofluorphosphate on plasma and blood viscosity in the rat.

Alpha macroglobulins (AM) are plasma proteins whose main function is to inactivate proteinases, protecting the tissues from the action of these enzymes. AM have influence on plasma viscosity (PV) and binds monofluorophosphate (MFP), which disturbs its homeostasis. The aim of this work was to evaluate whether the administration with MFP could modify blood viscosity. AM levels (micromol/l), PV (mPa.s), viscosity of red blood cells suspensions in NaCl 9 g/l (VES) and in autologue plasma (VEP) were measured in fifty-day old rats after a single dose of 80 micromol MFP or after 30 days of treatment with 80 micromol of MFP. Relative viscosity (RV) was calculated as the ratio VEP/PV. AM and PV increased significantly after 30 min of an oral dose of MFP. Controls (n=6), AM: 19.65+/-0.85, PV: 1.39+/-0.01, treated (n=6), AM: 22.88+/-0.75 (p<0.05), PV: 1.76+/-0.14 (p<0.05). After 30 days of treatment with MFP, AM and PV increased significantly. Controls (n=6), AM: 10.76+/-1.33, PV: 1.19+/-0.04, treated (n=6), AM: 17.66+/-1.27 (p<0.05), PV: 1.38+/-0.03 (p<0.05). The treatment with MFP modifies neither the VEP nor the RV. These results would indicate that AM and/or MFP did not interact with erythrocyte membrane and did not modify erythrocyte deformability.

Physiological differences between root suckers and saplings enlarge the regeneration niche in Eucryphia cordifolia Cav.

Many clonal plants produce vegetative recruits that remain connected to the parent plant. Such connections permit resource sharing among ramets, explaining the high survival rates of vegetative recruits during establishment under suboptimal conditions for sexual regeneration. We propose that differences in the regeneration niches of sexual and vegetative recruits reflect different physiological adjustments caused by parental supply of resources to the ramets. We conducted ecophysiological measurements in saplings and root suckers of Eucryphia cordifolia Cav., a tree species of the temperate rainforest of southern South America. We compared the following traits of saplings and suckers: gas exchange at the leaf level, crown architecture, daily crown carbon balance, biomass allocation to above-ground tissues (leaf-to-stem mass ratio, leaf mass area and leaf area ratio), xylem anatomy traits (lumen vessel fraction, vessel density and size) and stem ring width. We also correlated the growth rates of saplings and suckers with relevant environmental data (light and climate). Saplings showed morphological, architectural and physiological traits that enhance daily crown carbon balance and increase water-use efficiency, in order to supply their growth demands while minimizing water loss per unit of carbon gained. The radial growth of saplings diminished under dry conditions, which suggests a strong stomatal sensitivity to water availability. Suckers have low stomatal conductance, likely because the carbon supplied by the parent plant diminishes the necessity of high rates of photosynthesis. The low responsiveness of sucker growth to temporal changes in water availability also supports the existence of parental supply. The physiological differences between sexual and vegetative recruits satisfactorily explain the ecological niche of E. cordifolia, with saplings restricted to more closed and humid sites.

Management of congenital elevation deficiency due to congenital third nerve palsy and monocular elevation deficiency.

PURPOSE: To document the presentation and management of congenital III nerve palsy and monocular elevation deficiency to single ophthalmologist over a 14-year period. Surgical management was reviewed and visual outcome was analysed. METHODS: A retrospective study was conducted of all patients presenting during a period between 1992 and 2006 to the private practice of a paediatric ophthalmologist, with either congenital III or monocular elevation deficiency. For patients requiring surgical intervention pre- and post-surgical data were documented and analysed. RESULTS: A total of 19 congenital III and 13 monocular elevation deficiency patients were identified. There were eight surgical patients in each congenital III nerve palsy group and in the monocular elevation deficiency group. The congenital III group had a preoperative mean exotropia for near of -36 prism dioptres (PD) compared with postoperative mean exotropia for near -16 PD. Preoperative mean hypotropia for near of -19 PD was improved to postoperative mean hypotropia of -5 PD. The monocular elevation deficiency group had preoperative mean esotropia for near of +6 PD compared with postoperative mean exotropia for near -5 PD. Preoperative mean hypotropia for near of -15 PD was improved to postoperative mean hypotropia of -7 PD. At last follow up both groups had a majority of mild or no amblyopia noted. CONCLUSION: Superficially, congenital III and monocular elevation deficiency may appear similar, both frequently having ptosis and hypotropia as features. Careful clinical assessment of the horizontal alignment and the result of forced duction testing will usually allow them to be distinguished. Congenital III more frequently requires surgery for exotropia as well as surgery for hypotropia and monocular elevation deficiency more often requires surgery just for hypotropia. The ptosis surgery is similar for either diagnosis in this study. Significant cosmetic improvement, as well as excellent visual acuity outcomes can be achieved.

Optimal learning paths in information networks.

Each sphere of knowledge and information could be depicted as a complex mesh of correlated items. By properly exploiting these connections, innovative and more efficient navigation strategies could be defined, possibly leading to a faster learning process and an enduring retention of information. In this work we investigate how the topological structure embedding the items to be learned can affect the efficiency of the learning dynamics. To this end we introduce a general class of algorithms that simulate the exploration of knowledge/information networks standing on well-established findings on educational scheduling, namely the spacing and lag effects. While constructing their learning schedules, individuals move along connections, periodically revisiting some concepts, and sometimes jumping on very distant ones. In order to investigate the effect of networked information structures on the proposed learning dynamics we focused both on synthetic and real-world graphs such as subsections of Wikipedia and word-association graphs. We highlight the existence of optimal topological structures for the simulated learning dynamics whose efficiency is affected by the balance between hubs and the least connected items. Interestingly, the real-world graphs we considered lead naturally to almost optimal learning performances.

Edwards' measures for powders and glasses

Can one construct a thermodynamics for compact, slowly moving powders and grains? A few years ago, Edwards proposed a possible step in this direction, raising the fascinating perspective that such systems have a statistical mechanics of their own, different from that of Maxwell, Boltzmann, and Gibbs, allowing us to have some information while still ignoring dynamic details. Recent developments in the theory of glasses have come to confirm these ideas within mean field. In order to go beyond, we explicitly generate Edwards' measure in a 3D model. Comparison of the results with the irreversible compaction data shows very good agreement. The present framework immediately suggests new experimental checks.

Relative weight of glucose, insulin and parathyroid hormone in the urinary loss of phosphate by chronically diabetic rats.

This report deals with the relationships between glucose (G) and insulin on the tubular transport of phosphate (P) in chronically diabetic rats with high plasma levels of parathyroid hormone (PTH). Alloxan-induced diabetes leads to phosphorus depletion of the soft tissues. This phenomenon appears associated with weight loss and negative P balances caused by the increased urinary P excretion. Administration of 2 IU of insulin/100 g body weight (bw) to diabetic rats normalized their P balance and body weight. The effect of parathyroid function on the P metabolism of diabetic rats was investigated with balance experiments. Diabetic rats, intact or thyroparathyroidectomized (TPTX), have a greater urinary excretion of P than their controls. However, in control rats, the ratio intact:TPTX for urinary P is 1.0:0.76, showing the antiphosphaturic effect of parathyroid ablation. For diabetic animals, on the other hand, the ratio is 1.0:1.44. The simultaneous deficit of insulin and PTH thus quadruples the urinary P loss, instead of compensating for each other. The contribution of insulin deficit and hyperglycemia to the defect in tubular reabsorption (TRP) was investigated with clearance experiments (done on anesthetized, perfused rats). Five experimental groups were used: Controls (C), diabetics (D), controls + glucose (C + G), diabetics + insulin (D + I) and diabetics + insulin + glucose (D + I + G). All experimental groups showed a linear relationship between the TRP of P and G. The regression equation for C is significantly different (F = 40.1, P < 0.001) from that of D animals. The slope value measure the number of mumoles of P per mumol of G reabsorbed. For C and D rats, the ratio P:G approximates 1:4 and 1:20, respectively. The increase in P:G ratios represents the competition between both substrates for tubular resorption. Glycemias up to 11 mM (C and D + I) exist concurrent with the P:G ratio 1:4 Glycemias above 25 mM (D, C + G and D + I + G) produce a P:G ratio of 1:20. Fractional excretion of P (FEP) increased significantly in untreated, chronically diabetic rats (0.47 +/- 0.12 vs controls = 0.05 +/- 0.01, P < 0.001). After a single intramuscular injection of insulin, the FEP decreased as a function of insulin levels. To normalize the FEP of diabetic rats in short-term experiments, insulin had to be administered in doses that produce plasma insulin levels 25 times greater than normal. The general information afforded by the present experiments shows that in untreated, chronically diabetic rats, insulin deficit plays an indirect role. The absence of PTH enhances the effect of hyperglycemia. The latter and the concurrent tubular overload of glucose are the cause of hyperphosphaturia in these animals.

Severe hyperglycemia: a determinant factor for hypofiltration in alloxan diabetic rats.

The relationships among glomerular filtration rate, renal plasma flow and extracellular fluid volume were investigated in control and severely hyperglycemic (442+/-33 mg/dl) untreated, alloxan diabetic ats. Most of diabetic animals showed significant lower values of inulin clearance (diabetics, 0.55+/-0.07 ml/min.100 g; controls, 0.97+/-0.04) and p-aminohippurate clearance (diabetics, 2.11+/-0.39 ml/min.100 g; controls, 3.93+/-0.25). Diabetic rats exhibited reduced efficiency in tubular Na(+) reabsorption, increased urinary Na(+) excretion (diabetics, 3.12+/-0.27 mEq/day; controls, 1.25+/-0.14) and diminished values of plasma renin activity (diabetics, 3.34+/-0.44 ng/ml.h; controls, 8.64+/-0.79). Significant negative correlations were found between glycemia and renal hemodynamic variables. Acute overload with glucose further decreased these variables in both groups: inulin clearance in diabetics vs. controls, 0.26+/-0.04 vs. 0.44+/-0.05 ml/min.100 g; p-aminohippuric acid clearance in diabetics vs. controls, 1.09+/-0.20 vs. 1.55+/-0.21 ml/min.100 g. We conclude that chronically hyperglycemic alloxan diabetic rats showed diminished glomerular filtration rates (inulin clearance), renal plasma flow ( p-aminohippurate clearance) and extracellular fluid volume associated with urinary Na(+) losses and alterations in the renin-angiotensin system. Decreased renin-angiotensin system activity might reduce aldosterone secretion, which in turn could result in (successively) urinary sodium loss, extracellular fluid volume contraction and reductions in glomerular filtration and renal plasma flow.