Preclinical assessment of an anti-HTLV-1 heterologous DNA/MVA vaccine protocol expressing a multiepitope HBZ protein

BACKGROUND

Human T-lymphotropic virus 1 (HTLV-1) is associated with the development of several pathologies and chronic infection in humans. The inefficiency of the available treatments and the challenge in developing a protective vaccine highlight the need to produce effective immunotherapeutic tools. The HTLV-1 basic leucine zipper (bZIP) factor (HBZ) plays an important role in the HTLV-1 persistence, conferring a survival advantage to infected cells by reducing the HTLV-1 proteins expression, allowing infected cells to evade immune surveillance, and enhancing cell proliferation leading to increased proviral load.

METHODS

We have generated a recombinant Modified Virus Vaccinia Ankara (MVA-HBZ) and a plasmid DNA (pcDNA3.1(+)-HBZ) expressing a multiepitope protein based on peptides of HBZ to study the immunogenic potential of this viral-derived protein in BALB/c mice model. Mice were immunized in a prime-boost heterologous protocol and their splenocytes (T CD4+ and T CD8+) were immunophenotyped by flow cytometry and the humoral response was evaluated by ELISA using HBZ protein produced in prokaryotic vector as antigen.

RESULTS

T CD4+ and T CD8+ lymphocytes cells stimulated by HBZ-peptides (HBZ42-50 and HBZ157-176) showed polyfunctional double positive responses for TNF-α/IFN-γ, and TNF-α/IL-2. Moreover, T CD8+ cells presented a tendency in the activation of effector memory cells producing granzyme B (CD44+High/CD62L-Low), and the activation of Cytotoxic T Lymphocytes (CTLs) and cytotoxic responses in immunized mice were inferred through the production of granzyme B by effector memory T cells and the expression of CD107a by CD8+ T cells. The overall data is consistent with a directive and effector recall response, which may be able to operate actively in the elimination of HTLV-1-infected cells and, consequently, in the reduction of the proviral load. Sera from immunized mice, differently from those of control animals, showed IgG-anti-HBZ production by ELISA.

CONCLUSIONS

Our results highlight the potential of the HBZ multiepitope protein expressed from plasmid DNA and a poxviral vector as candidates for therapeutic vaccine.

Comparative Analysis of Gait Speed Estimation Using Wideband and Narrowband Radars, Thermal Camera, and Motion Tracking Suit Technologies

Research has shown that cognitive and physical functioning of older adults can be reflected in indicators such as walking speed. While changes in cognition, mobility, or health cause changes in gait speed, often gradual variations in walking speed go undetected until severe problems arise. Discrete clinical assessments during clinical consultations often fail to detect changes in day-to-day walking speeds and do not reflect walking speeds in everyday environments, where most of the mobility issues happen. In this paper, we compare four walking speed measurement technologies to a GAITRite mat (gold standard): (1) an ultra wideband radar (covering the band from 3.3 GHz to 10 GHz), (2) a narrow band 24-GHz radar (with a bandwidth of 250 MHz), (3) a perception Neuron Motion Tracking suit, and (4) a thermal camera. Data were collected in parallel using all sensors at the same time for 10 healthy adults for normal and slow walking paces. A comparison of the sensors indicates better performance at lower gait speeds, with offsets (when compared to GAITRite) between 0.1 and 20% for the ultra wideband radar, 1.9 and 17% for the narrowband radar, 0.1 and 38% for the thermal camera, and 1.7 and 38% for the suit. This paper supports the potential of unobtrusive radar-based sensors and thermal camera technologies for ambient autonomous gait speed monitoring for contextual, privacy-preserving monitoring of participants in the community.

78 DIFFERENT EXTENDERS TO HARVEST EQUINE EPIDIDYMAL SPERM AND THEIR INFLUENCE ON FREEZABILITY

Harvesting and freezing epididymal sperm is a technology that enables the preservation of the gene pool from animals that had died either unexpectedly or because of colic conditions. This technique may also be employed in animals that have to be euthanized because of traumatic injuries. Therefore, the objective of the present study was to improve the process of freezing epididymal sperm using a freezing extender without the prior centrifugation of the samples. Twelve stallions aging between 3 and 6 years and of different breeds were used (Quarter Horse, Mangalarga, and Brazilian Jumping Horse). Stallions were castrated, and the cauda epididymides were isolated from the testis. The connective tissue was carefully dissected, and the cauda epididymides were straightened. A 200-µL pipette tip was attached to a 20-mL syringe, and the cauda epididymides were flushed using 40 mL of either (A) BotuSemen® (Nidacon, Mölndal, Sweden) or (B) BotuCrio® (Nidacon). They were then immediately processed at room temperature (25°C). Samples flushed with B were randomly subjected to either of the 2 procedures: B1) directly loaded into 0.5-mL straws or B2) centrifuged at 600g for 10 min, the supernatant was discarded, and the pellet was resuspended with B and loaded into 0.5-mL straws. The straws were kept at 5°C for 20 minutes followed by another 20 min at 6 cm above liquid nitrogen before immersion. After thawing at 46°C for 20 s the samples were analyzed by computer-assisted semen analysis (HTM – IVOS 12) and plasma membrane integrity was assessed using fluorescent probes (carboxyfluorescein diacetate and propidium iodide). Data were analyzed by ANOVA followed by the Tukey test (P < 0.05). No differences were observed for the values of total motility (A: 57.1 ± 12.35, B1: 46.3 ± 10.0, B2: 47.2 ± 12.84), progressive motility (A: 25.5 ± 9.05, B1: 21.7 ± 9.02, B2: 20.7 ± 7.20), percentage of rapids (A: 40.6 ± 15.92, B1: 30.7 ± 10.51, B2: 32.6 ± 12.39), and plasma membrane integrity (A: 47.8 ± 9.56, B1: 45.0 ± 13.81, B2: 41.3 ± 8.74). It was found that the fluid derived from epididymal secretions, which composes seminal plasma, had no influence on sperm parameters, because there was no difference among freezing protocols. Therefore, flushing equine epididymal cauda with B and freezing the samples without centrifuging can be successfully used. Both extenders (A and B) were efficient in protecting epididymal sperm throughout the freezing process.

E-cadherin loss rather than beta-catenin alterations is a common feature of poorly differentiated thyroid carcinomas

AIMS

To investigate the immunohistochemical and molecular genetic features of the cadherins/catenins complex in thyroid carcinoma based on the hypothesis that poorly differentiated carcinoma of the thyroid represents an intermediate step between well-differentiated and undifferentiated carcinomas.

METHODS AND RESULTS

Immunohistochemistry for E-, P- and N-cadherins and alpha-, beta- and gamma-catenins was performed in a series of 17 cases of poorly differentiated carcinoma of the thyroid. All cases showed absence of membranous expression of E-cadherin with no aberrant expression of P- or N-cadherins; regarding catenins there was heterogeneous loss of expression with membranous immunolocalization of the three catenins in most cases. Molecular analysis of the E-cadherin gene and exon 3 of the beta-catenin gene was also performed by polymerase chain reaction/single-strand conformation polymorphism and sequencing. No mutations in either gene were detected in any case.

CONCLUSIONS

In contrast to previous reports, our results suggest that loss of E-cadherin rather than beta-catenin mutation is the crucial event in determining the differentiation 'level' of thyroid carcinomas.

Microsatellite instability, mitochondrial DNA large deletions, and mitochondrial DNA mutations in gastric carcinoma

Mitochondrial DNA (mtDNA) large deletions and mtDNA mutations have been demonstrated in various types of human cancer. The relationship between the occurrence of such alterations and the nuclear microsatellite instability (MSI) status of the neoplastic cells remains controversial. In an attempt to clarify the situation in gastric carcinoma, we studied, by PCR/SSCP and sequencing, five mitochondrial genes and two D-loop regions in 32 gastric carcinomas that had been previously screened for MSI and mitochondrial common deletion. MtDNA alterations were detected in 26 carcinomas (81%). All the mtDNA mutations, which occurred mainly in the D-loop and ND1 and ND5 genes, were transitions. D-loop alterations (insertions and/or deletions) were not significantly associated with mutations in the coding regions. There was a trend towards an inverse relationship between the occurrence of mitochondrial common deletion and mtDNA mutations. No significant relationship was observed between MSI status and mtDNA mutations, whereas the mitochondrial common deletion appeared to be almost exclusively restricted to MSI-negative tumors. The latter finding--almost no gastric carcinoma with MSI-positive phenotype has large deletions of mtDNA--needs to be confirmed in a larger series and in tumors from other organs.

Abnormalities of the E-cadherin/catenin adhesion complex in classical papillary thyroid carcinoma and in its diffuse sclerosing variant

The cadherin/catenin complex regulates cellular adhesion and motility and is believed to function as an invasion suppressor system. Several studies have identified alterations in the expression profiles of those molecules in different histotypes of thyroid carcinoma. The diffuse sclerosing variant (DSV) of papillary thyroid carcinoma (PTC) is a rare, highly invasive variant of PTC in which an impairment of cell-cell adhesion may play a major role. In an attempt to progress in the understanding of the clinicopathological features of DSV, this study examined eight cases of DSV, 18 cases of classical PTC and a control group of normal thyroid by immunohistochemistry (E-, P- and N-cadherins and beta-, gamma- and alpha-catenins). The E-cadherin gene was also studied by polymerase chain reaction/single strand conformation polymorphism (PCR/SSCP) and methylation-specific PCR (MSP). In contrast to classical PTC, which showed heterogeneous loss of E-cadherin expression, in almost every case of DSV a pronounced reduction was observed in its membranous expression, accompanied by a relocation to the cytoplasm. Inactivation of the E-cadherin/catenin complex appears to occur in DSV via two different pathways: E-cadherin alteration either through mutation (one out of the eight cases) or through methylation of the E-cadherin gene promoter (three out of five cases); and beta- and/or gamma-catenin alterations (three of the eight cases). Methylation of the E-cadherin gene promoter, abnormalities of E-cadherin expression and alterations of gamma-catenin were also detected in classical PTC. In DSV, as in classical PTC, there is neo-expression of P-cadherin in areas of squamous metaplasia and no N-cadherin expression. In conclusion, abnormalities of the E-cadherin/catenin complex appear to be more pronounced in DSV than in classical PTC. It remains to be shown whether or not such differences are associated with the more aggressive behaviour of DSV compared with classical PTC.

Myxoma of the mitral valve

Only rarely do myxomas originate from the mitral valve. This is the report of a 49-year-old woman presenting with congestive heart failure. The diagnosis of an intracardiac tumor involving the anterior cuspid of the mitral valve was made by transesophageal echocardiography. The patient underwent surgery for tumor resection and plasty of the valve was made with reconstruction and preservation of the valve. The diagnosis of myxoma was confirmed by histology. This is the 23rd case of myxoma of the mitral valve reported in the literature.

[Myocardial revascularization in left coronary trunk lesion in patients over 65 years old]

PURPOSE

To study the short and long-term follow-up of patients with left main coronary artery disease (LMCAD) and age over 65 years, by comparing the results with patients under 65 years-old.

METHODS

Twenty-two patients with LMCAD and mean age of 69 +/- 3.5 years (group I) were underwent isolated coronary artery bypass grafting (CABG) and compared to 31 patients with LMCAD, mean age of 54 +/- 7 years (group II), who also underwent isolated CABG. The life-table Kaplan-Meyer method was used to estimate the post-operative survival. The chi-square and Student "t" test were used when necessary.

RESULTS

Despite higher operative mortality in group I (9.1% x 3.2%), the difference was statistically not significant. The operative morbidity was similar in both groups. Actuarial survival at 4 years was 85% in group I and 95% in group II. Actuarial survival free of cardiac events was 69% in group II and 75% in group II.

CONCLUSION

The CABG is well tolerated and had low morbidity and acceptable mortality in old patients with LMCAD. The long-term survival in these patients was very similar to the younger patients.

Comparisons of models of cortical necrosis with segmental infarction

Sodium and water excretion were studied by standard clearance techniques in three experimental models where renal mass was reduced by superficial cortical necrosis (CN) or ischemic segmental infarction (SI). During hydropenia either CN or SI were able to conserve and regulate sodium to a very similar degree. After expansion of extracellular volume, CN reabsorbed less sodium and water than SI. In free-water clearance (CH2O) experiments, the 'apparent distal' sodium delivery was higher in CN than in SI, suggesting a decreased sodium and water reabsorption in the proximal tubules of juxtamedullary nephrons (JM). Both kidneys had similar CH2O when factored for inulin clearance but when CH2O was corrected for 'apparent distal' sodium delivery it was lower in CN than in SI, demonstrating an incapacity of JM to dilute urine. CN also showed less capacity to reabsorb free water than SI. Thus, the use of CN and SI within the same animal was useful to study functional differences between superficial and juxtamedullary nephrons. The present study also suggests that the kidney with superficial CN was unable to perform maximal urine dilution and concentration.

Phosphate transport in isolated rat inner medullary collecting duct

Phosphate transport by the inner medullary collecting duct of normal rats was studied using an in vitro microperfusion technique. Net (Jnet), lumen-to-bath (Jlb) and bath-to-lumen (Jbl) phosphate fluxes were measured using 32PO4 as tracer, in the absence of net water absorption. A net absorption of phosphate (22.3 +/- 3.3 pmol cm-2 s-1) was observed by direct determination, and was similar to the difference between the Jlb and Jbl (57.7 +/- 8.2 and 32.2 +/- 1.5 pmol cm-2 s-1 respectively). The addition of amiloride (10 microM) to the perfusate did not change the Jlb of phosphate but blocked the efflux of sodium. Also, the withdrawal of sodium from the bath and perfusion solution did not change the Jlb of phosphate. In parallel, the addition of ouabain (10 mM) to the bath fluid decreased the Jlb of sodium more (37%) than the Jlb of phosphate (12%) and did not change the Jbl of phosphate. The addition of arsenate (10 microM) to the perfusate both in the presence and in the absence of sodium caused a decrease in Jlb, but Jbl remained unchanged, and parathyroid hormone (10 U) added to the bath did not change the Jlb. The increase in pH of the bath and perfusion fluid was associated with an increase in the Jlb of phosphate, and the decrease in pH was similarly followed by a decrease in phosphate efflux. The Jbl did not change with the pH alterations. These data demonstrate that a net phosphate absorption takes place in rat inner medullary collecting duct perfused in vitro and that this transport appears to be independent of sodium absorption and the action of parathyroid hormone. Moreover, a decrease in luminal and bath pH induces a decrease in phosphate efflux.

Effect of peritubular hypertonicity on water and urea transport of inner medullary collecting duct

The effect of bath fluid hypertonicity on hydraulic conductivity (Lp) and [14C]urea permeability (Pu) of the distal inner medullary collecting duct (IMCD) was studied in the absence and in the presence of vasopressin (VP) using the in vitro microperfusion technique of rat IMCD. In the first three groups of IMCD, we observed that in the absence of VP the Lp was not different from zero when the osmotic gradient was created by hypotonic perfusate and isotonic bath fluid, but it was significantly greater than 1.0 x 10(-6) cm.atm-1.s-1 when the osmotic gradient was created by hypertonic bath and isotonic perfusion fluid. The increase in Lp was observed when the hypertonicity of the bath fluid was produced by the addition of NaCl or raffinose, but no such effect was observed with urea. The stimulated effect of bath fluid hypertonicity on Lp was also observed in the IMCD obtained from Brattleboro homozygous rats in which VP is absent. The NaCl hypertonic bath increased the Pu in the absence of VP. In another series of experiments with VP (10(-10) M) we observed that the hypertonic bath fluid increased in a reversible manner the VP-stimulated Lp of distal IMCD. However, the NaCl hypertonicity of the bath fluid was not able to increase dibutyryladenosine 3',5'-cyclic monophosphate-stimulated Lp. The Pu stimulated by VP (10(-10) M) increased twofold when the bath fluid was hypertonic. Therefore hypertonicity of the peritubular fluid produced by the addition of NaCl or raffinose increases the Lp and Pu in the absence and in the presence of VP. No such effect was noted with the addition of urea.

Renal involvement in leptospirosis: a pathophysiologic study

The kidney involvement in leptospirosis appears to be a special form of acute renal failure due to a higher frequency of polyuric forms and the presence of hypokalemia with an elevated urinary fractional excretion of potassium. Using a clearance technique, we detected higher fractional urinary potassium excretion in leptospirotic guinea pigs (26.5 +/- 4.7%) than in normal animals (14.1 +/- 2.8%, p < 0.05). After blocking distal NaCl reabsorption with furosemide, it was observed that in leptospirotic animals both fractional sodium excretion (40.0 +/- 7.4%) and fractional potassium excretion (136.3 +/- 32.7%) were higher than in normal animals (20.4 +/- 3.8%, p < 0.05, and 43.6 +/- 9.0%, p < 0.05, respectively). Microperfusion studies showed that the normal and leptospirotic medullary thick ascending limb had both identical transepithelial potential difference (+3.7 +/- 0.4 vs. 3.9 +/- 0.2 mV) and relative sodium-to-chloride permeability. The same technique showed that the osmotic water permeability (Posm; 0.9 +/- 0.4 x 10(-5) cm/s.atm) and diffusional permeability (34.7 +/- 6.6 x 10(-5) cm/s) observed in the leptospirotic inner medullary collecting duct (IMCD) in the presence of vasopressin were unchanged, as was also the case for urea permeability (3.74 +/- 0.7 x 10(-5) cm/s). These data show that acute renal failure in leptospirosis is characterized by tubular changes leading to potassium secretion probably due to a decrease in proximal sodium reabsorption. Furthermore, the inability to concentrate urine evidenced by the low P(o)sm present in leptospirotic animals is due, at least in part, to IMCD resistance to vasopressin.

Acute renal failure following hemorrhagic shock: protective and aggravating factors

Acute renal failure following hemorrhagic shock was studied in awake rats. The animals were bled to maintain the mean arterial blood pressure between 40 and 60 mm Hg during 180 min. After this period, the blood was reinfused and the rats were studied 24 h later. Hemorrhagic shock caused a less intensive renal injury than 60-min bilateral renal artery clamping. Renal function in the latter model was worse (p less than 0.05) as shown by serum creatinine (SCr) (0.75 +/- 0.10 vs 1.2 +/- 0.2 mg/dL), blood urea nitrogen (BUN) (26.0 +/- 2.8 vs 53.0 +/- 8.5 mg/dL), fractional excretion of sodium (FENa, %) (0.3 +/- 0.1 vs 1.8 +/- 1.0) and potassium (FEK, %) (41.4 +/- 5.7 vs 76.3 +/- 14.2) and urine/plasma creatine (U/PCr (86.4 +/- 15.7 vs 38.8 +/- 15.5). The rats which received verapamil (10 micrograms/kg/min) prior and during the HS did not show increase in SCr (0.5 +/- 0.06 vs 0.75 +/- 0.1 mg/dL, p less than 0.05). This effect was also observed in the rats which received intravenous allopurinol (40 mg/kg) before HS, SCr did not increase (0.5 +/- 0.04 vs 0.75 +/- 0.1 mg/dL, p = 0.05), suggesting a protective effect of those substances in HS.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of acyclovir on renal function

The renal effects of acyclovir (100 mg/kg body weight i.p. for 7 days) were studied in rats. All animals became polyuric and presented an increase in blood urea nitrogen and fractional excretion of sodium and potassium. During hypotonic saline infusion, the acyclovir-treated rats showed higher distal fractional delivery compared to normal rats (27.8 +/- 4.7 vs. 11.3 +/- 0.9%, p less than 0.01) and a lower ratio of free-water clearance to distal sodium delivery (33.5 +/- 7.8 vs. 57.2 +/- 3.9%, p less than 0.02). Following hypertonic saline infusion, the ratio of osmolar to inulin clearance was higher in acyclovir rats (47.8 +/- 7.4%) than in normal rats (27.0 +/- 4.8%), whereas the ratio of free-water reabsorption to osmolar clearance was lower in the acyclovir rats (13.6 +/- 4.6 vs. 38.2 +/- 3.2%, p less than 0.01). These findings suggest an effect of acyclovir on the proximal tubule, thick ascending limb and/or inner medullary collecting duct (IMCD). In vitro measurements of 3H2O permeability of perfused IMCD of normal rats showed that vasopressin (50 microU/ml) added to the bath increased the diffusional water permeability (43.4 +/- 4.8 vs. 105.6 +/- 9.1 x 10(-5) cm/s), while in acyclovir rats, the control value (58.8 +/- 9.1 x 10(-5) cm/s) did not increase significantly in the presence of vasopressin (71.3 +/- 13.6 x 10(-5) cm/s). These results suggest that high doses of acyclovir produce azotemia and an abnormal function of the proximal tubule and thick ascending limb associated with resistance to vasopressin of the IMCD.

Renal concentrating defect in protein malnutrition: the role of the thick ascending limb of Henle and inner medullary collecting duct

The present study was carried out to examine the effect of chronic dietary protein restriction on renal water handling in the rat. During hypotonic saline infusion, the malnourished rats showed a lower free-water clearance, corrected by inulin clearance (7.2 +/- 0.4%), than normal rats (13.6 +/- 2.5%, p less than 0.051), although the fractional distal delivery of sodium did not differ from normal. Throughout hypertonic saline diuresis the free-water reabsorption (TcCH20) corrected by inulin clearance was lower in malnourished rats (6.62 +/- 0.64%) than in control animals (9.25 +/- 0.62, p less than 0.05). Moreover, when TcH20 was referred to the osmolar clearance, malnourished animals showed lower values than normal. These results suggest a defect in NaCl transport in the thick ascending limb of Henle. In vitro measurements of diffusional water permeability (PDW) in the inner medullary collecting duct (IMCD) obtained from malnourished rats showed an increase from 40.0 +/- 5.4 x 10(5) cm/s to 71.3 +/- 5.4 x 10(5) cm/s by adding maximum effective concentration (50 microU/ml) of arginine vasopressin (VP) to the bath. These values were not different from the PDW observed in the IMCD of normal rats. In another series of microperfusion experiments, the hydraulic conductivity in IMCD of malnourished rats measured also in the presence of maximum effective concentration of VP was 29.7 +/- 3.4 x 10(-6) cm/atm/s, a mean value not significantly different from that observed in the IMCD of normal rats (35.2 +/- 4.3 x 10(-6) cm/atm/s).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of atrial natriuretic factor and cyclic guanosine monophosphate on water and urea transport in the inner medullary collecting duct

We examined the action of high (2 x 10(-8)M) and low (6 x 10(-9)M) concentrations of atrial natriuretic factor (ANF) on water and urea transport in the rat inner medullary collecting duct (IMCD) using the in vitro microperfusion technique. We measured the hydraulic conductivity (Lp x 10(-6) cm/atm per second) and both lumen-to-bath (Pu(lb] and bath-to-lumen (Pu(bl)) 14C-urea permeabilities (Pu x 10(-5) cm/s) in the absence and in the presence of vasopressin (VP). High concentrations of ANF were able to inhibit the maximum activity of (50 microU/ml) VP-stimulated Lp but physiological concentration of ANF inhibit only submaximum activity (10 microU/ml) of VP-stimulated Lp. The hydrosomotic effect of dibutyryl-cyclic 3.5 adenosine monophosphate (cAMP) (10(-4)M) was unchanged by high concentrations of ANF (2 x 10(-8)M). Also we found that high (10(-4)M) and low (10(-6)M) concentrations of exogenous cyclic 3,5-guanosine monophosphate (GMP) while unable to change the Lp in the absence of VP, decreased the maximum activity of VP-stimulated Lp significantly. We also found that ANF inhibits partially and in a reversible manner the VP-stimulated Pu(lg) but not the VP-stimulated Pu(bl). These results demonstrated that plasma concentrations of ANF observed during volume expansion (10(-10)M) are able to inhibit submaximum activity of VP-stimulated (10 microU/ml) Lp in the rat IMCD, this effect seems to occur before cAMP formation and it appears to be mediated by cGMP. ANF (6 x 10(-9)M) also reduced the VP-stimulated urea outflux.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial peptide and cGMP effects on NaCl transport in inner medullary collecting duct

We examined the action of atrial natriuretic factor (ANF) on Na+ and Cl- transport in in vitro microperfused inner medullary collecting ducts (IMCD) isolated from rat kidneys. First we studied the isotopic fluxes at low perfusion rates (7 nl/min). The results showed that ANF added to bath decreased lumen-to-bath flux (Jl----b) of Na+ and increased Na+ bath-to-lumen flux (Jb----l). This was substantiated by a direct demonstration that ANF reduces net Na+ and Cl- absorption. The effect of ANF on Jl----b and Jb----l of Na+ was also observed at high perfusion rates (25 nl/min). The inhibitory effect of ANF was observed even when Na+ Jl----b was stimulated by vasopressin (VP). ANF (6 x 10(-11) M) added to bath increased Cl- Jb----l and generated a negative lumen potential difference (PD). These two effects were inhibited by furosemide and by the replacement of Na+ by choline and Cl- by SO4(2-) in the bath fluid. These observations are compatible with the existence of a Na(+)-Cl(-)-K+ cotransport mechanism stimulated by ANF. Moreover, the effects of guanosine 3',5'-cyclic monophosphate (cGMP) added to the bath on PD, Jl----b, and Jb----l of Na+ were similar to those observed with ANF. Thus, physiological concentrations of ANF inhibit directly Na+ and Cl- absorption in IMCD by two mechanisms, 1) by increasing cotransport Na(+)-Cl(-)-K+ secretion and 2) by inhibiting NaCl absorption both in the absence and in the presence of VP. These effects on NaCl transport appear to be mediated by cGMP.

Effect of furosemide on water and urea transport in cortical and inner medullary collecting duct

The present in vitro microperfusion study examined whether furosemide has an effect on hydraulic conductivity (Lp X 10(-6) cm/sec.atm) and 14C-urea permeability (Pu X 10(-5) cm/sec) in inner medullary collecting ducts (IMCD) and cortical collecting tubules (CCT) isolated from rat and rabbit kidneys. Furosemide added to the bath fluid decreased arginine-vasopressin (AVP)-stimulated Lp of rat IMCD in a dose-dependent manner, with the threshold effect at 10(-6) M. Furosemide (10(-4) M) reduced Lp from 20.5 +/- 2.3 to 12.1 +/- 1.2 (P less than 0.01) reversibility, but had no effect when added to the perfusate. In addition, furosemide reduced dibutyryl cyclic AMP-stimulated Lp from 20.3 +/- 1.1 to 11.2 +/- 1.6 (P less than 0.01). This effect of furosemide was also observed with indomethacin, a PGE2 synthesis inhibitor. The addition of indomethacin (10(-4) M) to AVP (50 microU/ml) increased Lp from 24.7 +/- 2.3 to 29.7 +/- 2.8 (P less than 0.001), which was reduced to 20.3 +/- 2.6 (P less than 0.001) when furosemide was added to indomethacin in the bath. The inhibitory effect of furosemide on AVP-stimulated Lp was also observed in rabbit IMCD (Lp decreased from 12.8 +/- 0.8 to 5.15 +/- 1.46, P less than 0.02), but it was not observed in the CCT isolated from rabbit kidneys (7.96 +/- 1.87 with AVP vs. 7.94 +/- 1.41 with AVP + furosemide). Furthermore, in rat IMCD the stimulatory effect of AVP on Pu from 7.7 +/- 0.4 to 26.8 +/- 1.3 was reduced by furosemide to 19.7 +/- 1.2 (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of vasopressin on sodium transport across inner medullary collecting duct

We have used rat inner medullary collecting ducts (IMCD) perfused "in vitro" to study the effect of vasopressin (VP) on the unidirectional Na+ flux (in nmol.cm-2.s-1). We found that, at a high perfusion rate in the basal state, 24Na lumen-to-bath flux (Jl----b) was greater than the bath-to-lumen flux (Jb----l) (4.88 +/- 0.15 vs. 2.57 +/- 0.21), resulting in a significant net flux (Jnet) (P less than 0.001). Addition of 10 microU/ml of lysine vasopressin (LVP) to the bath produced a stable increase in Jl----b to 6.66 +/- 0.35 (P less than 0.001) without significant effect on Jb----l. Measuring directly the net flux absorption at lower perfusion rate (8 nl/min), we observed that LVP (10 microU/ml) produced a reversible stimulation on Jnet from 1.39 +/- 0.14 to 2.79 +/- 0.23 (P less than 0.01). The transtubular potential difference (PD) measured in the middle and final third of IMCD showed a small but significant PD (0.30 +/- 0.02 mV lumen positive) that increased significantly to 0.60 +/- 0.04 mV in the presence of LVP. However, dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP, 10(-4) M) added to the bath fluid did not change the JNa+l----b, nor was 1-desamino-8-D-arginine vasopressin (50 microU/ml), a specific V2-agonist, able to increase the Na+. We also demonstrated that JNa+l----b stimulated by LVP from 4.70 +/- 0.08 to 6.33 +/- 0.26 (P less than 0.01) was completely and reversibly inhibited by V1-antagonist, d(CH2)Tyr(Me)AVP, to 4.79 +/- 0.05. On the other hand, the absence of Ca2+ in the bath or the addition of amiloride to the lumen fluid or ouabain to the bath fluid completely inhibited AVP-stimulated JNa+l----b. Therefore, AVP and LVP increase Na+ absorption in the rat IMCD by increasing the Na+ outflux, probably generated by an increase of luminal membrane Na+ permeability modulated by extracellular Ca2+ and mediated through V1-receptors and independent of cAMP cascade.

Neurosarcoidosis: therapeutic success with methotrexate

Sarcoidosis affects the nervous system in 5% of cases. Treatment with corticosteroids is usually effective. We describe the case of a patient with neurosarcoidosis in which therapy with prednisone failed whereas the result of methotrexate administration was satisfactory.

Acute renal failure of leptospirosis: nonoliguric and hypokalemic forms

Acute renal failure induced by leptospirosis was studied in 56 patients. A higher frequency of nonoliguric renal failure was observed with lower morbidity and mortality rates than in oliguric forms. In addition, 45% of the patients in this series were hypokalemic, and no hyperkalemic patients were seen. A prospective study in 11 patients showed an initially elevated urinary fractional potassium excretion that fell simultaneously with the high urinary fractional sodium excretion and the urinary K/Na ratio, suggesting an increased distal potassium secretion due to an increased distal sodium delivery consequent to functional impairment of the proximal reabsorption of sodium.

The effect of protein restriction on the severity and recovery from ischemic renal failure

The effects of chronic dietary protein restriction on ischemic renal failure were evaluated in rats subjected to 90 min of bilateral renal clamping. The rats were kept on either 20% casein (regular) diet or casein-free (protein-free) diet 10 days before and 21 days after renal injury. Rats on regular protein diet showed higher levels of BUN and serum creatinine and had a lower inulin clearance (microliter/min/100 g BW) than animals on protein-free diet (289 +/- 34 vs 582 +/- 103, p less than 0.05) 2 days after ischemia. However, the inulin clearance measured 21 days following ischemia was significantly higher in rats on regular diet (1468 +/- 181) than those maintained on protein-free diet after ischemia (560 +/- 167). When unilateral 90 min ischemia was performed in rats on regular diet, the postischemic kidneys showed an incomplete recovery of the inulin clearance (226 +/- 35) compared to the contralateral kidney (900 +/- 116), 21 days after ischemia; whereas in rats on a protein-free diet the inulin clearance averaged 106 +/- 17 in the postischemic kidney and 345 +/- 41 in the right kidney. When left renal ischemia and contralateral nephrectomy were performed, the inulin clearance was 1149 +/- 74 in rats on regular diet and 534 +/- 60 in rats on protein-free diet, 21 days following renal insult. These results suggest that protein restriction can play a protective role against renal ischemia in an initial phase, but it limits the late recovery from ischemia. The presence of a normal contralateral kidney inhibits the functional recovery of the postischemic kidney and a contralateral nephrectomy produces a compensatory functional hypertrophy of the postischemic kidney, even in rats on a protein-free diet.

[Hyponatremia: study of its epidemiology and mortality]

To determine the prognosis of hyponatremia in an unselected population, we collected clinical and laboratory data and determined the outcome of hospitalization for all hyponatremic patients in a general hospital during a three month period. Fourty-nine episodes of hyponatremia were analyzed. More than 90% of them were observed in hospitalized patients and were of dilutional type, and 34% were classified as severe hyponatremias (Nas less than 118 meq/l.). Diuretics plus salt restriction without water restriction were the main identifiable causes. Neurological disturbances were observed in 10.8% of patients and persisted in 4.3% of then after the treatment. Slow correction of hyponatremia was the treatment used in these patients (0.16 +/- 0.004 meq/l.h). Ten patients died, but in only one case the dead could have been caused by hyponatremia. The results showed that the morbidity and mortality of the hyponatremia is low in our institution, few patients had neurological disturbances and a favorable outcome in all of them was obtained with a slow correction of hyponatremia.

[Catatonic syndrome caused by autoimmune disease: spontaneous remission]

The psychiatric manifestations of systemic lupus erythematosus and other autoimmune diseases, which may precede by many years systemic involvement, should be held in mind by both the internist and psychiatrist. This case report focuses on a female catatonic patient without metabolic disturbances, whose evolution did not suggest a schizophrenic disorder. Immune complexes were demonstrated to be present in cerebrospinal fluid (CSF) obtained during psychotic crisis and immunologic tests showed circulating immune complexes with a positive antinuclear factor. (1/800) and a nucleolar pattern with immunofluorescence. The psychiatric picture receded concomitantly with a fall in CSF immune complexes and with an increase in circulating immune complexes, without the administration of immunosuppressive drugs. The catatonic syndrome is a rare manifestation in patients with autoimmune disease and few cases have been reported without systemic manifestation. This report emphasizes the need for increased awareness of the psychiatric effects brought about by autoimmune diseases and shows that CSF immune complexes are valuable markers for their diagnosis.

Calcium transport across rat inner medullary collecting duct perfused in vitro

Ca2+ transport by the inner medullary collecting duct (IMCD) of normal rats was studied using the "in vitro" microperfusion technique. Net (Jnet), lumen-to-bath (Jl----b), and bath-to-lumen (Jb----l) fluxes of Ca2+ were measured in the absence of net water absorption using 45Ca as a tracer. In the absence of an electrochemical gradient, an important net absorption of Ca2+ (11.1 +/- 1.6 pmol.cm-2.s-1), similar to the difference between the Jl----b and Jb----l, was observed by direct determination at low (5-6 nl/min) and high (12-17 nl/min) perfusion rates. The Jl----b of Ca2+ was reduced by the addition to the bath fluid of ouabain (10(-3) M) and verapamil (10(-4) M), by the presence of amiloride (10(-5) and 10(-3) M) and verapamil (10(-4) M) in the luminal fluid, or by perfusion with a Na+-free solution. Neither the presence of verapamil (10(-4) M) and ouabain (10(-3) M) in the bath nor the withdrawal of Na+ from bath and perfusion solution was able to modify the Jb----l of Ca2+. Incrementing Ca2+ bath concentration increased proportionally the Jb----l of Ca2+. Therefore Ca2+ outflux is in part dependent on Na+-K+-adenosinetriphosphatase luminal membrane Na+ transport and in part inhibited by verapamil. However, Ca2+ influx is independent of Na+ transport, is not blocked by verapamil, but is increased by Ca2+ transtubular gradient, indicating the presence of a passive diffusion mechanism.

[Prognostic accuracy and efficacy of treatment at intensive care units evaluated by the APACHE II system]

The APACHE II system can stratify acutely ill patients on hand of simple physiological measurements. In a retrospective study, 121 patients were stratifyed in regard to the mortality rates in three groups: first one with the mortality rate of 10% second one with 47%, and the third one with 100%. Mortality rates predicted and observed were similar (40.5% and 39.7%, respectively, p greater than 0.8; 95% confidence interval 31.8% to 49.7%). The APACHE II system is useful for accurate stratification of patients and the evaluation of treatment efficacy.

[Renal insufficiency due to lymphomatous infiltration of the kidney: report of 3 cases and review of the literature]

Renal failure in patients with lymphoma or leukemia may be brought about by different causes, including ureteral obstruction, hypercalcemia, hyperuricemia, amyloidosis, immunologically mediated nephrosis and paraproteinemic nephropathy. Lymphomatous or leukemic infiltration of the kidneys is a frequent finding at autopsy but is rarely seen as a cause of renal failure. In this report three patients with lymphomatous infiltration of the kidneys causing renal failure are described. Clinical and laboratory criteria for establishment of diagnosis in such cases are suggested. Using these diagnostic criteria, a renal biopsy may not be necessary.

Effect of potassium depletion on ischemic renal failure

The present study was carried out to examine the effect of potassium depletion in rat kidneys subjected to a temporary ischemic event produced by clamping of left renal artery. The postischemic kidneys of rats on a normal diet with adequate potassium intake showed an increase in H2O, Na and K excretion, with no change in inulin clearance whereas significant differences were found in potassium-deprived rats. Potassium depletion was brought about by dietary K deprivation for 10 days. K-depleted rats (serum K = 2.5 +/- 0.1 mEq/l) had a decrease in inulin clearance of the postischemic kidney from 1.01 +/- 0.10 to 0.43 +/- 0.05 ml/min (p less than 0.01), and a greater increase in fractional excretion of H2O, Na and K when compared to normal rats. The postischemic kidney from both normal and hypokalemic rats showed a decrease in Na-K-ATPase of the inner stripe of the outer medulla. These data indicate that short-term ischemia produces polyuria, increases natriuresis and kaliuresis, associated, at least in part, with a decrease in Na-K-ATPase in the inner stripe of the outer medulla (probably the thick ascending limb of Henle) and that K depletion potentiates ischemic renal failure.

Morpho-functional patterns of kidney injury in the experimental leptospirosis of the guinea-pig (L. icterohaemorrhagiae)

Thirty-seven guinea-pigs experimentally infected with a virulent strain of L. icterohaemorrhagiae, were submitted to a renal function study as evaluated through the maximal urinary concentration (MUC) test, blood urea nitrogen (BUN) and afterwards had their kidneys examined by light and electron microscopy. Vascular changes were also studied after the administration of colloidal carbon as a marker. Through the MUC test and BUN determination, two groups of tubulo-interstitial lesions can be visualised, one in animals without renal sufficiency, manifested chiefly by cell edema with RE dilation and another, in animals with renal insufficiency, characterised not only by marked cell edema and mitochondrial changes, but also by proximal tubule regenerative aspects without overt tubular necrosis. Interstitial edema and focal nephritis was prominent in both groups, a finding which minimises their role in the pathogenesis of renal failure in experimental leptospirosis. Vascular injury, affecting the vessels of the renal microcirculation chiefly at the cortico-medular junction, was observed in both groups. Its severity and extension ran parallel to the intensity of the tubular injury. This suggests a simultaneous action of a noxious agent liberated by the leptospires over both structures, tubular damage being accentuated by the local circulatory changes.

Calcium transport in isolated perfused pars recta of proximal tubule

1. Ca2+ transport was examined in segments of rabbit pars recta isolated from the renal cortex by the technique of in vitro perfusion. 2. The bidirectional Ca2+ flux was determined by adding 45Ca to the bath and to the perfusate sequentially. Five tubules were perfused with Ringer-HCO-3 solution containing 0.5% albumin and bathed in the same solution, which maintained the ionized Ca2+ at the same concentration in the perfusate and bath. The outflux of Ca2+ was 169 +/- 18 pEq cm-1 min-1, while the influx was 53 +/- 13 pEq cm-1 min-1. The difference between these two numbers, the net Ca2+ absorption, is equal to 116 +/- 19 pEq cm-1 min-1. The flux ratio, 3.79 +/- 0.87, was significantly higher than 0.91 +/- 0.01 predicted by the Ussing equation from the transtubular potential difference (PD = -1.3 +/- 0.2 mV). 3. The effect of ouabain and transtubular PD on Ca2+ outflux was studied with rabbit serum ultrafiltrate as perfusate and rabbit serum as the bath. When 10(-5) M ouabain was added to the bath the transtubular PD fell from -2.4 +/- 0.3 mV to -0.65 +/- 0.06mV and fluid absorption decreased from 0.83 +/- 0.15 to 0.42 +/- 0.2 nl min-1 mm-1, whereas Ca2+ outflux remained unchanged (before = 160 +/- 13 pEq cm-1 min-1, after = 167 +/- 7 pq cm-1 min-1). 4. When tubules were perfused with and Na+ -free solution (NaCl replaced by choline chloride), Ca2+ outflux, 170 +/- 170 11 pEq cm-1 min-1, was the same as that obtained with the normal perfusion solution. 5. These results indicate that: a) the pars recta has the capacity for net absorption of significant amounts of Ca2+ that is apparently independent of Na+ efflux; b)Ca2+ transport across the pars recta occurs by a mechanism other than simple diffusion and c), unlike Na+ transport, Ca2+ outflux is not sensitive to ouabain.

Calcium and phosphate transport in isolated segments of rabbit Henle's loop

Calcium and phosphate transport was examined in rabbit thin descending, thin ascending, and thick ascending limbs of Henle by in vitro perfusion of isolated tubular segments. Permeability coefficients for these segments with 45Ca and 32PO4 were determined for both lumen-to-bath and bath-to-lumen directions. Both the thin descending and thin ascending limbs were found to be relatively impermeable to both 45Ca and 32PO4. In neither segment were we able to show evidence for net transport of calcium or phosphate. In contrast, the thick ascending limb of Henle showed a decrease in calcium lumen-to-bath concentration from 0.97 +/- 0.02 to 0.88 +/- 0.02 when perfused at 4.8 nl min-1. 45Ca lumen-to-bath and bath-to-lumen fluxes were 19.96 +/- 1.05 and 9.89 +/- 0.02 peq-min-1-cm-1, respectively, and the potential difference was +3.8 +/- 0.3 mV (lumen positive). The observed calcium flux ratio was significantly higher than that predicted by Ussing's equation. When ouabain was added to the bath the potential difference fell to +1.1 +/- 0.3 mV, whereas the calcium efflux was only slightly diminished (29.5 +/- 5.3-23.7 +/- 5.1 peq-cm-1-min-1). Ouabain had no effect on the influx of Ca across the thick ascending limb of Henle. There was no net transport of phosphate across the thick ascending limb. Phosphate permeability was exceedingly low bidirectionally across the thick ascending limb. Our findings indicate: (a) all segments of Henle's loop are relatively impermeable to calcium and phosphate; (b) net transport of phosphate seems to be absent in Henle's loop; (c) net calcium reabsorption, which cannot be explained by passive mechanisms, occurs in the thick ascending limb.

Sodium chloride and water transport in the medullary thick ascending limb of Henle. Evidence for active chloride transport

Transport of NaCl and water was examined in the rabbit medullary thick ascending limb of Henle (ALH) by perfusing isolated segments of these nephrons in vitro. Osmotic water permeability was evaluated by perfusing tubules against imposed osmotic gradients. In these experiments the net transport of fluid remained at zero when segments of thick ALH were perfused with isotonic ultrafiltrate in a bath of rabbit serum in which the serum osmolality was increased by the addition of either 239+/-8 mosmol/liter of raffinose or 232+/-17 mosmol of NaCl indicating that the thick ascending limb of Henle is impermeant to osmotic flow of water. When these tubules were perfused at slow rates with isosmolal ultrafiltrate of same rabbit serum as used for the bath, the effluent osmolality was consistently lowered to concentrations less than the perfusate and the bath. That this decrease in collected fluid osmolality represented salt transport was demonstrated in a separate set of experiments in which it was shown that the sodium and chloride concentrations decreased to 0.79+/-0.02 and 0.77+/-0.02 respectively when compared with the perfusion fluid concentrations. In each instance the simultaneously determined transtubular potential difference (PD) revealed the lumen to be positive with the magnitude dependent on the perfusion rate. At flow rates above 2 nl.min(-1), the mean transtubular PD was stable and equal to 6.70+/-0.34 mv. At stop-flow conditions this PD became more positive. Ouabain and cooling reversibly decreased the magnitude of this PD. The transtubular PD remained positive, 3.3+/-0.2 mV, when complete substitution of Na by choline was carried out in both the perfusion fluid and the bathing media. These results are interpreted to indicate that the active transport process is primarily an electrogenic chloride mechanism. The isotopic permeability coefficient for Na was 6.27+/-0.38 x 10(-5) cm.s(-1) indicating that the thick ALH is approximately as permeable to Na as the proximal convoluted tubule. The chloride permeability coefficient for the thick ALH was 1.06+/-0.12 x 10(-5) cm.s(-1) which is significantly less than the chloride permeability of the proximal tubule. These data demonstrate that the medullary thick ascending limb of Henle is water impermeable while having the capacity for active outward solute transport as a consequence of an electrogenic chloride pump. The combination of these characteristics allows this segment to generate a dilute tubular fluid and participate as the principal energy source for the overall operation of the countercurrent multiplication system.