Knockdown of unc119c results in visual impairment and early-onset retinal dystrophy in zebrafish

PURPOSE

UNC119 proteins are involved in G protein trafficking in mouse retinal photoreceptors and Caenorhabditis elegans olfactory neurons. An Unc119 null allele is associated with cone-rod dystrophy in mouse, but the mechanism leading to disease is not understood. We studied the role of Unc119 paralogs and Arl3l2 in zebrafish vision and retinal organization resulting from unc119c and arl3l2 knockdown.

METHODS

Zebrafish unc119c was amplified by PCR from retina and pineal gland cDNA. Its expression pattern in the eye and pineal gland was determined by whole-mount in-situ hybridization. unc119c and arl3l2 were knocked down using morpholino-modified oligonucleotides (MO). Their visual function was assessed with a quantitative optomotor assay on 6 days post-fertilization larvae. Retinal morphology was analyzed using immunohistochemistry with anti-cone arrestin (zpr-1) and anti-cone transducin-α (GNAT2) antibodies.

RESULTS

The zebrafish genome contains four genes encoding unc119 paralogs located on different chromosomes. The exon/intron arrangements of these genes are identical. Three Unc119 paralogs are expressed in the zebrafish retina, termed Unc119a-c. Based on sequence similarity, Unc119a and Unc119b are orthologs of mammalian UNC119a and UNC119b, respectively. A third, Unc119c, is unique and not present in mammals. Whole mount in-situ hybridization revealed that unc119a and unc119b RNA are ubiquitously expressed in the CNS, and unc119c is specifically expressed in photoreceptive tissues (pineal gland and retina). A Unc119 interactant, Arl3l2 also localizes to the pineal gland and the retina. As measured by the optomotor response, unc119c and arl3l2 knockdown resulted in significantly lower vision compared to wild-type zebrafish larvae and control morpholino (MO). Immunohistological analysis with anti-cone transducin and anti-cone arrestin (zpr-1) indicates that knockdown of unc119c leads to photoreceptor degeneration mostly affecting cones.

CONCLUSIONS

Our results suggest that Unc119c is the only Unc119 paralog that is highly specific to the retina in zebrafish. Unc119c and Arl3l2 proteins are important for the function of cones.

Eosinophilic cystitis in a 4-year-old boy: successful long-term treatment with cyclosporin A

A 4-year-old Jewish boy presented with dysuria, urinary dribbling, increased urinary frequency, and new onset of diurnal enuresis. An infiltrating solid mass involving the entire bladder wall was found. Biopsy revealed "tumor-forming" eosinophilic cystitis, a rare bladder lesion of unclear cause. Antitoxocariasis treatment was unsuccessful. High-dose corticosteroids failed. The child's clinical condition and bladder sonographic findings continued to deteriorate. Treatment with cyclosporin A was given for 8 months, with a complete clinical, radiologic, and histopathologic cure and no side effects. Two years of follow-up showed a complete recovery.

Ambulatory blood pressure monitoring in children with a solitary kidney - a comparison between unilateral renal agenesis and uninephrectomy

BACKGROUND

In experimental animals, a reduction in renal mass leads to glomerulosclerosis of the residual parenchyma and eventual renal failure. In humans, however, data on the influence of nephrectomy or agenesis on future functional parameters and hypertension are as yet controversial.

OBJECTIVE

To evaluate blood-pressure patterns in children with a solitary kidney as a result of either unilateral renal agenesis (URA) or uninephrectomy (UNX) and correlate them to the increase in size of the remaining kidney.

METHODS

Twenty-eight children with a solitary kidney were divided into two groups: the URA group, with 18 subjects (13 male and five female, with a mean age of 9.6 +/- 3.9 years), and the UNX group, which contained 10 subjects (four male and six female, with a mean age of 14.0 +/- 2.7 years). The mean time since nephrectomy was 8.7 years. Each study group was assigned an age-, weight- and height-matched control group. In all subjects, ambulatory blood pressure monitoring was performed using the SpaceLabs model no. 90207. Daytime and night-time were defined as 0800-2200 h and 2200-0800 h, respectively. Urinalysis, serum creatinine and urea results were recorded for all the study group participants. The size of the remaining kidney was determined by ultrasound examination. The percentage increase in kidney size, as calculated from standard kidney-length-against-age nomograms was correlated to the percentage deviation from normal blood pressure values.

RESULTS

The mean 24 h, daytime and night-time systolic blood pressure (SBP) readings were significantly higher in children in the URA group than in those in the corresponding control group (111.4 +/- 7.5 mmHg versus 106.9 +/- 6.7 mmHg, P < 0.004; 115.2 +/- 3.1 mmHg versus 110.7 +/- 3.4 mmHg, P < 0.004; and 105.2 +/- 2.6 mmHg versus 101.2 +/- 1.8 mmHg, P < 0.002, respectively). Daytime heart rate was found to be significantly reduced (84.4 +/- 5.2 versus 87.8 +/- 8.2 beats/min, P < 0.04). In the UNX group, 24 h mean, systolic and diastolic blood pressure (DBP), as well as heart rate, did not differ from control values. Daytime systolic and diastolic blood pressures were higher than those of the controls (119.8 +/- 4.0 mmHg versus 115.5 +/- 3.8 mmHg, P < 0.02; and 72.7 +/- 4.0 mmHg versus 70.0 +/- 11.0 mmHg, P < 0.02, respectively). Nocturnal dipping was present in all groups and was of equal magnitude in the corresponding control groups. The mean 24 h diastolic blood pressure load was significantly greater in URA patients than in controls (19.6 versus 10.8%, respectively, P < 0.01). In the UNX group, the blood pressure loads were similar to those of controls. The percentage increase in length of the remaining kidney was found to correlate positively with the percentage delta increase in both systolic and diastolic blood pressure.

CONCLUSIONS

Compared with the age-, height- and weight-matched controls, the children with a solitary kidney caused by URA had an elevated mean 24 h SBP. In contrast, those with UNX had mean 24 h blood pressure values similar to those of their controls. A rise in SBP was, however, seen in both groups during the daytime hours. Thus, the presence of a solitary kidney, for whatever reason, may be pathogenetically linked to a raised blood pressure, and this linkage may be more pronounced in URA. The delta increase in size of the remaining kidney may serve as a prognostic indicator of blood pressure elevation.

Elevated salt and nitrate levels in drinking water cause an increase of blood pressure in schoolchildren

AIM

To assess the influence on blood pressure in schoolchildren, of elevated sodium (Na(+)) and nitrate (NO(-)(3)) levels in the drinking water.

METHODS

The blood pressure was recorded in three groups of age- and weight-matched schoolchildren (fourth and fifth graders) ingesting differing Na(+) and NO(-)(3) concentrations with their drinking water. Group 1 (n = 452) imbibed high-Na(+), high-NO(-)(3) water (196 and 49 mg/l, respectively); group 2 (n = 418) consumed low-Na(+), high-NO(-)(3) water (25 and 49 mg/l, respectively) and group 3 (n = 86) drank low-Na(+), low-NO(-)(3) water (35 and 25 mg/l, respectively). The chloride (Cl(-)) concentrations varied in parallel to those of Na(+).

RESULTS

Systolic blood pressure (SBP) and mean arterial pressure (MAP) were significantly increased in group 1 versus groups 2 and 3 (115.6 +/- 12.2 and 86.4 +/- 9.6 mm Hg vs. 111.1 +/- 11.6 and 83 +/- 8.3 and 107 +/- 8.8 and 81 +/- 7.2 mm Hg, respectively, p < 0.05). The SBP in group 2 was also significantly higher than in group 3 (111.1 +/- 11.6 vs. 107 +/- 8.8 mm Hg; p < 0.05).

CONCLUSIONS

Elevated Na(+) (and possibly Cl(-)) in combination with high NO(-)(3) concentrations in drinking water leads to an increase of SBP and MAP in fourth and fifth graders. The effects of Na(+) (and/or Cl(-)) and NO(-)(3) on SBP and MAP appear to be additive, yet independent of each other.

A bioassay evaluation of the urinary antibacterial efficacy of low dose prophylactic antibiotics in children with vesicoureteral reflux

PURPOSE

We evaluated by means of a bioassay the efficacy of 4 different antibiotics administered in a prophylactic dose to children with vesicoureteral reflux.

MATERIALS AND METHODS

A total of 159 urine samples from 53 children taking prophylactic antibiotics with proved vesicoureteral reflux were tested. The children were divided into 4 groups according to the antibiotic given, which included nalidixic acid, cephalexin, cotrimoxazole and cefixime. Urine samples were collected in the morning, at noon and in the evening, and each sample was bioassayed for growth inhibition of a standard Escherichia coli. The urine volume used was specifically determined for each antibiotic, and growth inhibition by this specific volume was equivalent to that produced by standard diffusion disks. In addition, the specific gravity, which reflected urinary concentration of each sample, was measured.

RESULTS

Mean patient age plus or minus standard deviation of the 4 groups was 53 +/- 41 for nalidixic acid, 23 +/- 34 for cephalexin, 55 +/- 35 for cotrimoxazole and 47 +/- 35 months for cefixime, respectively. In children less than 2 years old specific gravity was higher in the morning (1.021 +/- 0.0006 versus 1.0008 +/- 0.0004 at 8 a.m. and 2 p. m., respectively, p <0.05). In contrast, in children older than 4 years the specific gravity was higher in the afternoon and evening hours (1.019 +/- 0.003 versus 1.007 +/- 0.003 at 2 p.m. and 8 a.m., respectively, p <0.05). The percentage of patients who demonstrated growth inhibition in all 3 samples of the test day was 7%, 6%, 69% and 44% for nalidixic acid, cephalexin, cotrimoxazole and cefixime, respectively (p <0.001 for cotrimoxazole and cefixime versus nalidixic acid and cephalexin. Divided into morning, noon and evening, the percentage of samples that demonstrated growth inhibition was 85.7%, 21.4% and 7.1% for nalidixic acid, 37.5%, 12. 5% and 6.3% for cephalexin, 100%, 92.3% and 76.9% for cotrimoxazole and 100%, 77.7% and 55.5% for cefixime, respectively. A direct correlation was found between specific gravity and growth inhibition (r = 0.55, p <0.001).

CONCLUSIONS

Urine concentration during the day is dependent on age with older children having more concentrated urine in the latter part of the day. Growth inhibition is enhanced by concentrated urine. Compared to nalidixic acid and cephalexin, cotrimoxazole and cefixime produce a sustained bactericidal effect for about 60% of a 24-hour day due to the longer half-life.

Effect of granulocyte and granulocyte macrophage colony stimulating factors (G-CSF and GM-CSF) on neonatal neutrophil functions

Although there are many studies on the effect of granulocyte and granulocyte-macrophage colony stimulating factors (G/GM-CSF) on adult neutrophil functions, there is little information regarding their influence on neonatal cells. We studied the in vitro effect of G/GM-CSF on neutrophil chemotaxis, polarization, and superoxide anion generation in 47 neonates compared with 35 adults. We found that G-CSF and GM-CSF significantly enhanced the chemotaxis of newborn infants' neutrophils, normalizing their chemotactic defect [from 35 +/- 7 cells/field (mean +/- SE) to 49 +/- 5 cells/field with G-CSF, p < 0.05 and to 55 +/- 4 cells/field with GM-CSF, p < 0.001]. It is notable that the maximal neutrophil response to the cytokines was observed particularly in the newborn infants with severe impairment in their chemotactic activity. Statistical analysis of the data showed a significant inverse correlation, which supported this observation (r = -0.6, p < 0.02 for G-CSF; r = -0.76, p < 0.001 for GM-CSF). The reduced polarization of neonatal compared with adult cells [71 +/- 5% versus 86 +/- 2% (mean +/- SE), p < 0.05], was corrected by CSF-priming (to 87 +/- 4% with G-CSF and to 92 +/- 2% with GM-CSF, p < 0.05). In addition, the neutrophil superoxide generation was significantly improved in both groups following the CSF-priming. GM-CSF and G-CSF gave comparable results in all functions studied except that GM-CSF improved superoxide release to a greater extent. This study shows a significant improvement of the neonatal neutrophil functions following in vitro CSF-priming and contributes to a better understanding of the neonatal neutrophil behavior when treated with G/GM-CSF.

The increase of renal pelvis dilatation in the fetus and its significance

OBJECTIVE

To determine the effects of the changes in fetal renal pelvis dilatation on post-natal diagnosis and outcome.

METHODS

Prenatal sonographic fetal renal anteroposterior diameters of > or = 4 mm in the second trimester, which persisted to > or = 7 mm in the third trimester, were the inclusion criteria. Fifty-six fetuses and 73 renal units with normal karotypes and a solitary sonographic finding of renal pyelectasis, which met the inclusion criteria, were followed, post-natally, until the age of 30 months. The neonates were categorized into three groups, according to their final diagnosis: No hydronephrosis, pelvi-ureteric junction obstruction and hydronephrosis from other causes. The neonates were also categorized according to their outcome: no treatment, follow-up only and surgical treatment.

RESULTS

In 17 neonates (30.4%), and 19 renal units, the diagnosis of hydronephrosis was excluded post-natally. In 39 neonates (69.6%), and 54 renal units, an urinary tract pathology was confirmed. The dynamics of pyelectasis in the second and third trimesters of pregnancy differed significantly among the neonates when categorized according to the final diagnosis (P < 0.05), or according to outcome (P < 0.05).

CONCLUSION

It is possible to predict, and distinguish between, long-term conservative and surgical treatments of renal pelvis dilatation in the third trimester of pregnancy.

Night-time polyuria and urine hypo-osmolality in enuretics identified by nocturnal sequential urine sampling--do they represent a subset of relative ADH-deficient subjects?

Early morning urine osmolality was tested in two urinary specimens, one taken immediately upon awakening and the other approximately 30 min thereafter, in 52 enuretic and 15 non-enuretic children. In a follow-up study, using the same study population, urine osmolality and volume were measured sequentially at 3-h intervals at 19.00, 22.00, 01.00, 04.00 and 07.00 h. Thereafter, all enuretics were treated by intranasal DDAVP for a 6-month period. There were no differences in urinary osmolality between enuretic and non-enuretic children when comparing the two early morning specimens. Nor were there any differences between groups in urine osmolalities at 19.00, 01.00 and 07.00 h. In contrast, at 04.00 h, urine osmolality was significantly lower in 17 of 52 enuretics [designated as ADH-negative (ADH-)] compared to the remaining enuretics [designated as ADH-positive (ADH+)] and non-enuretic children (610 +/- 251 vs 995 +/- 195 and 1089 +/- 195 mosmol/kg H2O, respectively, p < 0.05). This decreased osmolality was paralleled by an increase in urine production during the time period 01.00-04.00 (83 +/- 24 vs 52 +/- 18 and 45 +/- 22 ml, respectively, p < 0.05). At the end of the 6-month period of DDAVP treatment, the percentage response was similar between the ADH- and ADH+ enuretics (79% vs 75%). However, the time taken to achieve a response was quicker in the ADH- subjects. These data suggest the existence of a subgroup of enuretics whose underlying pathophysiology is the development of nocturnal polyuria probably due to a relative night-time ADH deficiency. Nocturnal sequential monitoring of urinary osmolality, as described above, allows identification of this subgroup.

Acute renal failure in a neonate caused by the transplacental transfer of a nephrotoxic paraprotein: successful resolution by exchange transfusion

Acute renal failure was diagnosed within 6 days of birth in a full-term neonate. The mother was known to have a monoclonal gammopathy, immunoglobulin G (IgG) lambda, discovered a year before pregnancy on being investigated for hematuria and proteinuria. Her renal function was intact. Maternal renal biopsy performed at the time showed a focal proliferative glomerulonephritis with nonfibrillary homogeneous mesangial and intramembranous electron-dense deposits. Immunoperoxidase staining was positive for IgG and lambda and kappa light chains along the glomerular and tubular basement membranes. Pregnancy was uneventful. Protein electrophoresis and immunofixation of the infant girl's serum and urine samples showed the presence of a paraprotein electrophoretically identical to that found in the mother. Exchange transfusion resulted in a rapid improvement of renal function in parallel to the disappearance of the monoclonal component.

Seasonal variation in systemic onset juvenile rheumatoid arthritis in Israel

OBJECTIVE

To determine whether there is a seasonal peak onset of systemic juvenile rheumatoid arthritis (SOJRA) suggestive of an infectious etiology. We examined the seasonal variability of SOJRA in Israel.

METHODS

A multicenter retrospective chart review of 59 patients with SOJRA, enrolled from 10 rheumatology units or pediatric departments in Israel. All patients met defined criteria of SOJRA.

RESULTS

Fifty-nine patients (31 female, 28 male) were followed from 1982 to 1997. Their mean age was 7.1 +/- 4.3 years (range 0.9-16). Forty-six were Jewish and 13 were Arabs or of Bedouin origin. Eighteen patients (31%) had disease onset in the winter, 16 (27%) in the spring, 12 (20%) in the summer, and 13 (22%) in the fall. Twenty-eight patients had a monophasic disease subtype, while 31 had a chronic or cyclic subtype. The seasonal onset in the patients with the monophasic type versus the chronic or the cyclic type shows 7 versus 11 in the winter, 7 versus 9 in spring, 8 versus 4 in summer, and 6 versus 7 in fall, respectively.

CONCLUSION

There is no seasonal pattern to SOJRA disease onset in Israel. However, the disease onset of patients having the chronic or the polycyclic subtype tends to be more common in winter and spring. Since patients with this type have more severe disease, it is possible that another specific infectious agent is one of the factors involved in the pathogenesis of the disease. Larger sampling and multicenter studies are required to clarify this point.

Is greater than normal nocturnal heart rate in children with renal scars a predictor of reflux nephropathy?

BACKGROUND

The existence of renal scars constitutes the major etiologic factor for the development of hypertension during childhood. Elevated blood pressure in this setting can be considered a secondary form of hypertension. Certain forms of secondary hypertension have been associated with a lower than normal nocturnal fall in blood pressure. Resting heart rate per se has recently been reported to be an independent predictor of risk for cardiovascular mortality irrespective of age and the presence or lack of hypertension.

OBJECTIVE

To ascertain the responses of heart rate and blood pressure in normotensive children with renal scars without, however, proteinuria and renal failure.

METHODS

Ten children with renal scars documented by a 99Tc dimercaptosuccinic acid (DMSA) scan were subjected to ambulatory blood pressure monitoring. Ten age-matched and sex-matched healthy children served as the control group. Serum urea and creatinine levels, calculated rate of clearance of creatinine, microalbuminuria, plasma renin activity, and levels of aldosterone and catecholamines were determined for each subject.

RESULTS

Average daytime and night-time systolic and diastolic blood pressures for the two groups did not differ. Subjects in both groups demonstrated the physiologic decrease in blood pressure during sleep (normal 'dipper' response), which was of equal magnitude for these two groups. Mean daytime heart rates were 92+/- 13 beats/min in children with renal scars versus 80+/-11 beats/min in controls (NS). Mean and minimal heart rates during night-time in children with renal scars were found to be significantly greater [79+/-6 versus 65+/-5 beats/min (mean) and 61+/-10 versus 56+/-7 beats/min (minimal), P < 0.01]. Parameters of renal function, plasma renin activity, and levels of aldosterone and catecholamines were similar for these two groups.

CONCLUSION

Despite their having an equivalent physiologic dip in blood pressure during night-time, normotensive children with renal scars have a significantly greater nocturnal heart rate than do control subjects.

Idiopathic non-obstructive hypertrophic cardiomyopathy, vitamin B12 deficiency and gastric adenocarcinoma: an unreported association in a teenager

A 14-year-old boy presented with anorexia and weakness whereon the diagnosis of dimorphic anaemia was made. An excellent response to iron and vitamin B12 was observed. In addition, the patient had non-obstructive hypertrophic cardiomyopathy. At endoscopy 2.5 years later, an adenocarcinoma was diagnosed and the patient underwent a high subtotal gastrectomy. To the best of our knowledge, this rare association has never been reported in children.

CONCLUSION

We report a youngster with pernicious anaemia, associated with nonobstructive hypertrophic cardiomyopathy in whom gastric adenocarcinoma was found. Patients with pernicious anaemia are at greater risk of developing gastric carcinoma than the general population, therefore we recommend routine periodic gastroscopic surveillance in the paediatric population with pernicious anaemia.

Neonatal neutrophil inflammatory responses: parallel studies of light scattering, cell polarization, chemotaxis, superoxide release, and bactericidal activity

Neutrophil dysfunction among newborn infants, especially those born prematurely, is well recognized, but the mechanism responsible for this phenomenon is yet to be clarified. In this study, we evaluated the stimulus response coupling in neutrophils from 90 healthy newborns and 96 healthy adults in an effort to establish whether defective neonatal neutrophil function is a result of impaired signal perception or immature responsiveness. Measurement of rapid- and slow-light scattering responses (LSR) to 1 microM FMLP stimulation revealed that neonatal neutrophils have about one-half the corresponding responsiveness of adult cells (rapid-LSR: 6.1 +/- 3.1 arbitrary light intensity units vs. 12.0 +/- 2.8, P < .001; and slow-LSR: 5.0 +/- 2.5 vs. 9.1 +/- 2.0; P < .001). The same markedly reduced activity was observed in newborn neutrophil chemotaxis and bactericidal activity in comparison with adult cells. Nevertheless, low FMLP concentrations (less than 1 nM) induced no difference in cell polarization between newborn and adult neutrophils, yet at higher FMLP concentrations, the newborn revealed significantly reduced cell polarization. Our data suggest that newborn infants bear a fully functional FMLP signal perception but lack the full capacity of inflammatory responsiveness.

Torticollis as the sole initial presenting sign of systemic onset juvenile rheumatoid arthritis

We describe a 6-year-old girl with acute torticollis as the initial manifestation of systemic onset juvenile rheumatoid arthritis (JRA). She presented with isolated torticollis for 2 weeks, followed by daily intermittent fever and polyarthritis. We discuss the pathogenesis of cervical spine involvement in JRA and the clues to early diagnosis.

Relapsing Henoch-Schönlein purpura associated with a tubo-ovarian abscess due to Morganella morganii

Henoch-Schönlein purpura is the most common vasculitis in children. It is frequently preceded by either viral or bacterial infections of the upper respiratory tract. We present a 15-year-old female who developed recurrent episodes of Henoch-Schönlein purpura. Eventual investigation of the patient's abdominal pain, initially attributed to vasculitis involving the gastrointestinal tract, revealed a left tubo-ovarian abscess caused by Morganella morganii. Salpingo-oophorectomy resulted in complete remission of the disease process.

Urinary tract infection in premature infants: the role of imaging studies and prophylactic therapy

BACKGROUND

The prevalence of urinary tract infection (UTI) in premature infants ranges from 4% to 25%. It is surprising, however, that scant information exists regarding management of UTI in premature infants, particularly the need for radiologic evaluation of the urinary tract and the use of preventive antibiotic therapy after the first episode of UTI occurs. The aim of this study was to answer these questions.

PATIENTS AND METHODS

Twenty-seven (8%) premature infants (< 1750 gm birth weight) born during the period from 1990 through 1993 had UTI. Eleven of them were of extreme low birth weight (ELBW) (birth weight < 1000 gm). Ultrasound examination of the urinary tract was performed in all premature infants 7 days after a diagnosis of UTI was made and was repeated 1 month later, if disease was detected. Voiding cystography was performed in 21 premature infants (8 with ELBW) 6 to 8 weeks after a diagnosis of UTI was made.

RESULTS

The mean birth weight of premature infants with UTI was 1112 +/- 294 gm. The prevalence of UTI was significantly higher (p < 0.01) in infants with ELBW (13%) compared with that in premature infants with birth weight >1000 gm (6%). The male/female ratio in all premature infants was 2.9:1 and was significantly higher in infants with ELBW (10:1; p < 0.01). Organisms involved were Klebsiella (59%), Candida albicans (15%), Escherichia coli (15%), and Enterobacter (11%). Only premature infants with ELBW had Candida UTI. Five premature infants (four with ELBW) had mild transient hydronephronis, and one had persistent hydronephrosis and hydroureter. Voiding cystography showed that three premature infants had vesicoureteral reflux and that one had a bladder diverticulum. All premature infants with pathologic voiding cystography had birth weight >1000 gm and had normal ultrasound examination.

CONCLUSIONS

Premature infants with birth weight 1000 to 1750 gm should be given preventive antibiotic therapy at least until imaging evaluation (ultrasonography and voiding cystography) is complete. Premature infants with ELBW are more susceptible to fungal infection and do not seem to have underlying urinary tract abnormalities. Prophylactic therapy and voiding cystography may be unwarranted in this population subset.

Pefloxacin in adriamycin induced nephrotic syndrome in the rat

BACKGROUND

Pefloxacin, a fluorinated 4-quinolone, has recently been advocated as a first-line treatment for minimal-change nephropathy (MCN) or focal segmental glomerulosclerosis (FSGS). To further evaluate this issue we have utilized an animal model resembling human MCN, namely adriamycin-induced nephrotic syndrome in Wistar male rats.

METHODS

Adriamycin at a dose of 7 mg/kg was injected intravenously to all rats at day zero. Rats were divided into two groups: group A (n = 20) given only water served as the control group while group B (n = 19) was administered pefloxacin at 150 mg/kg. At days 7, 14, 21 and 28, the rats were placed in metabolic cages and daily proteinuria determined.

RESULTS

The nephrotic syndrome developed in all rats within 7 days of adriamycin administration. At day 7, proteinuria in group B was 173 +/- 78 vs 423 +/- 626 mg/day in group A, P < 0.02, but thereafter at days 14, 21 and 28, no significant difference in urinary protein excretion was noted.

CONCLUSIONS

These results suggest that in this animal model of NS mimicking human MCN, pefloxacin's antiproteinuric effect is only of a mild and transitory nature. In view of the above data and the overall results in human patients (detailed herein), the use of pefloxacin as definitive treatment of the NS cannot be recommended.

A urethral catheter knot: a rare complication of cystourethrography

Complications of voiding cystourethrography are infrequent. We report a rare complication of knotting of the catheter within the bladder, necessitating surgical removal of the catheter through the urethra.

Effect of recurrent pregnancies on the evolution of adriamycin nephropathy

BACKGROUND

In rats with incipient adriamycin nephropathy, pregnancy increases urine protein excretion and mean arterial pressure, with no changes in the glomerular filtration rate. Renal histology is normal and the glomerular TxB2/PGE2 ratio is increased.

METHODS

In the present study we evaluated the influence of repeated pregnancies on the evolution of adriamycin nephropathy. Two weeks after a first delivery, rats were mated again and were followed till 35 days after the second delivery.

RESULTS

In pregnant rats with adriamycin nephropathy, urine protein excretion and mean arterial pressure returned to values identical to those found in age-sex-matched virgin rats with adriamycin nephropathy. At the end of the second pregnancy, mean arterial pressure and urine protein excretion were again elevated, compared with virgin rats with adriamycin nephropathy. Thirty-five days after the second delivery, urine protein excretion and mean arterial pressure remained elevated, 296 +/- 50 mg/day vs 115 +/- 26 and 121 +/- 4 vs 110 +/- 1 mmHg respectively, P < 0.05. Glomerular filtration rate remained unchanged 0.84 +/- 0.09 vs 0.79 +/- 0.09 ml/min in virgin rats with adriamycin nephropathy. The glomerular TxB2/PGE2 ratio was decreased, contrasting with the first pregnancy. At the end of the second pregnancy, histological examination of the kidneys in rats with adriamycin nephropathy revealed a significant increase in mesangial expansion. It was even more marked 35 days later, at the last follow-up, with a semiquantitative score of 162 +/- 29 vs 81 +/- 20 in virgin adriamycin nephropathy rats, P < 0.05.

CONCLUSIONS

In rats with adriamycin nephropathy, repetitive pregnancies seem to aggravate the natural course of the disease in an irreversible fashion. The earlier changes in glomerular prostanoid synthesis, particularly on thromboxane, may play a pathogenic role by activating mesangial cell matrix synthesis.

Adriamycin-related hypertension in pregnant rats: response to a thromboxane receptor antagonist

1. In previous works we have described the development of hypertension and aggravation of proteinuria in rats who became pregnant after the administration of Adriamycin. This was associated with an increase in the glomerular thromboxane B2-prostaglandin E2 ratio. 2. To assess the pathogenetic role of thromboxane in this model, female Wistar rats were mated 2 weeks after receiving Adriamycin (3.5 mg/kg intravenously). Rats were then treated with the thromboxane-receptor antagonist daltroban, 60 mg day-1 kg-1 orally, beginning on day 11 of pregnancy. Systolic blood pressure, proteinuria and the urinary excretion of thromboxane B2, 6-keto-prostaglandin F1 alpha and prostaglandin E2 were measured serially before mating, and on days 14 and 21 of pregnancy. The results were compared with those in Adriamycin-(treated) pregnant rats not treated with daltroban, Adriamycin-treated virgin rats and normal virgin or pregnant rats either treated or untreated with daltroban. 3. In daltroban-treated pregnant and virgin rats treated with Adriamycin, systolic blood pressure remained normal, whereas it increased significantly (P < 0.05) in untreated animals. On day 14, blood pressure was higher in non-daltroban-treated Adriamycin-treated pregnant rats than in non-daltroban-treated Adriamycin-treated virgin rats. Treatment had no effect on blood pressure in normal virgin or pregnant rats. Proteinuria was higher in pregnant rats treated with Adriamycin than in Adriamycin-treated virgin rats, but it was not reduced by daltroban.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful treatment of Finnish congenital nephrotic syndrome with captopril and indomethacin

Two infants with biopsy-proven microcystic Finnish congenital nephrotic syndrome (onset at birth) were treated with a combination of captopril and indomethacin for 2 1/2 and 2 years, respectively; they had a marked reduction of urinary protein excretion without further need for albumin infusions. One infant has end-stage renal disease; the other infant's glomerular filtration rate has remained within normal limits.

Antiviral activity of mice with chronic renal failure--an assessment using peritoneal effluents

Antiviral activity (AVA) determined by the inhibition of the cytopathic effect (CPE) of vesicular stomatitis virus (VSV) on mice fibroblasts, was measured in the peritoneal effluent of mice. Four groups of animals (each group numbering 30 mice) were studied. Group 1 consisted of sham operated mice and served as the control group. Group 2 underwent implantation of silastic matter (of which the Tenckhoff catheter is made). In group 3, chronic renal failure was induced. Group 4 comprised those mice in which both chronic renal failure was induced and silastic matter implanted. Optical density readings, directly related to the inhibition of CPE were 0.66 +/- 0.01, 0.59 +/- 0.08, 0.85 +/- 0.06 and 0.86 +/- 0.13 for groups 1, 2, 3 and 4, respectively (p < 0.01 for groups 1 and 2 versus 3 and 4). Virus control readings indicative of the CPE of VSV without the presence of peritoneal effluent were 0.58 +/- 0.07, not significantly different from those obtained in groups 1 and 2. They were, however, significantly below values from groups 3 and 4 (p < 0.05). These data show that AVA is undetectable in the peritoneal effluent of normal mice. Chronic renal failure produces an enhancement of AVA. Silastic matter (Tenckhoff catheter) implantation does not play a role in the production of AVA.

Aplastic anemia in neonatal lupus erythematosus

OBJECTIVE

To describe an infant with neonatal lupus erythematosus associated with aplastic anemia.

SETTING

The pediatric department in a tertiary-care hospital.

INTERVENTIONS

Packed red blood cell transfusions and a 3-week course of high-dose steroid therapy.

MEASUREMENTS/MAIN RESULTS

The patient presented with severe anemia and a circumscribed, reticular, macular rash on the face and neck at 5 months of age. Skin lesion biopsy revealed epidermic hyperkeratosis, hydropic degeneration of the basal layer, and deposition of immunoglobulins and granular C1q at the dermoepidermal junction. Ro/SS-A antibodies were present in the infant. BFU-E (erythroid progenitor burst-forming unit) colonies in bone marrow increased by about tenfold when suppressor CD8+ T lymphocytes were removed, indicating immune suppression of hematopoiesis. High-dose steroid therapy failed. The infant subsequently developed gram-negative sepsis, severe metabolic acidosis, and consumptive coagulopathy and died.

CONCLUSIONS

Neonatal lupus erythematosus may present as part of a spectrum. The disease may range from mild and transient to a severe, life-threatening condition requiring immediate intervention, as in the case reported here. This is the first report of neonatal lupus associated with aplastic anemia due to immune-mediated suppression of hematopoiesis.

Effect of timing of antihypertensive therapy on glomerular injury: comparison between captopril and diltiazem

Recent studies have suggested that the progression of experimental chronic renal disease may be prevented by early use of antihypertensive drugs. It is unclear, however, whether such therapies may also affect established and progressive renal disease. In the present study we compared the effects of captopril (CEI) and diltiazem (CCB), started either at week 10 or at week 24 on the evolution of adriamycin nephropathy (AN). Rats were studied at weeks 7, 16, 24, 32, and 38 of the disease. None of the treatments influenced the development of nephrotic range proteinuria. The use of CCB from week 10 was even associated with increased proteinuria. The moderate hypertension of ADR rats was reduced to the same degree with both drugs. Inulin clearance (GFR) was significantly reduced in all ADR rats. However, in ADR rats treated with CEI from week 10 and in those treated with CCB from week 24, the GFR was relatively higher. Glomerular injury, evaluated by semiquantitative methods, was not ameliorated by CEI treatment. Earlier CCB treatment (week 10) worsened glomerular lesions, whilst CCB treatment initiated at week 24 reduced significantly the degree of mesangial expansion and focal glomerular sclerosis. We conclude that, in addition to their common antihypertensive action, the specific effect of drug therapy seems to be crucially time dependent.

Adriamycin nephropathy: a model to study effects of pregnancy on renal disease in rats

The influence of pregnancy on the evolution of primary renal disease is still a matter of controversy. Hypertension and derangement of renal function may occur. The pathophysiology of these complications is poorly understood. In the present study, we assessed the influence of pregnancy on the evolution of adriamycin (Adr) nephropathy. Four groups of animals were studied: 1) control virgin rats (C), 2) normal pregnant rats (NP), 3) virgin rats with nephropathy (Adr), and 4) pregnant rats with nephropathy (Adr-P). Inulin clearance measured at the end of pregnancy in awake rats was similar in NP (1.68 +/- 0.20 ml/min) and C (1.39 +/- 0.03 ml/min). In Adr-P rats, it tended to decrease (1.22 +/- 0.7 vs. 1.93 +/- 0.44 ml/min in Adr rats). Mean arterial pressure was increased in Adr-P rats (137 +/- 2.5 vs. 95 +/- 3.2 mmHg in NP; P < 0.001). Urinary protein excretion was 216 +/- 61 mg/day in Adr-P compared with 28.7 +/- 18 mg/day in Adr (P < 0.001). A significant increase in the glomerular thromboxane B2-to-prostaglandin E2 ratio was found in Adr-P rats (1.15 +/- 0.26 vs. 0.52 +/- 0.12 in Adr rats; P < 0.03). In NP rats, no change was observed. Kidneys and placentas were normal on light and electron microscopy. Thus pregnant rats with adriamycin nephropathy developed a clinical picture with several features of preeclampsia. Changes in glomerular prostanoid synthesis might play a role in the development of this complication.

Once daily cefixime compared with twice daily trimethoprim/sulfamethoxazole for treatment of urinary tract infection in infants and children

We conducted a randomized prospective multicenter study to compare the safety and efficacy of once daily oral cefixime (8 mg/kg) to twice daily oral trimethoprim/sulfamethoxazole (TMP/SMX) (8/40 mg/kg/day) for the treatment of acute urinary tract infection in children ages 6 months to 13 years. Seventy-six patients (38 in each group) were studied. Thirty-seven percent were younger than 3 years of age. Escherichia coli was the most common isolate in both groups (85%). Eighty-five percent of all Gram-negative organisms were susceptible to TMP/SMX and all were susceptible to cefixime. Seventy-two percent of all patients were febrile at the time of diagnosis. Both groups were treated for 7 to 10 days. Peripheral white blood cell counts, erythrocyte sedimentation rate, body temperature and urinalysis returned to normal at the same rate in both groups. No failures were observed and relapse occurred in 3 cases within the 4 weeks after treatment (2 in the cefixime group and one in the TMP/SMX group). Side effects were observed in 14% of the cefixime group and 16% of the TMP/SMX group and were all mild enough not to necessitate discontinuation of therapy. We conclude that the efficacy and safety of cefixime administered once daily compared favorably with TMP/SMX administered twice daily for acute uncomplicated urinary tract infection.

Effect of the prostacyclin analogue iloprost in sodium-depleted rats pretreated with captopril

Previous studies have shown that administration of captopril to sodium-depleted rats decreases the glomerular filtration rate (GFR) and blunts the increase in glomerular prostacyclin synthesis normally occurring in response to sodium depletion. To clarify the relationship between these two responses, iloprost, a stable analogue of prostacyclin, was administered to Na-depleted, captopril-treated (LNC) rats. At a dosage not affecting systemic blood pressure (12.5 ng/kg/min), iloprost increased GFR in LNC rats by 25% (from 0.26 +/- 0.03 to 0.35 +/- 0.03 ml/min/100 g body wt, P less than 0.01), without significant effects on renal plasma flow. No effect was observed in control rats. The results suggest that altered prostacyclin synthesis could contribute to the decrease of GFR in this model.

Potassium load prevents the decrease of GFR induced by captopril in sodium-depleted rats

Captopril decreases the glomerular filtration rate (GFR) in Na-depleted rats and inhibits the stimulation of glomerular prostanoid synthesis induced by Na depletion. Because K loading stimulates glomerular prostanoid production in normal rats, we studied the effects of K loading in Na-depleted captopril-treated (LNC) rats. Potassium, but not Cl, loading stimulated the glomerular synthesis of 6-ketoprostaglandin F1 alpha (PGF1 alpha) and thromboxane B2 (TxB2). Urinary kallikrein-like activity (UKALLV) and plasma aldosterone increased in K-loaded animals. LNC rats had lower clearances of inulin (CIN) and p-aminohippurate (CPAH) than controls (0.22 +/- 0.02 vs. 0.94 +/- 0.07 and 0.56 +/- 0.12 vs. 2.23 +/- 0.23 ml.min-1.100 g body wt-1, both P less than 0.01). KCl-loaded LNC rats had CIN and CPAH greater than LNC (0.64 +/- 0.16 and 1.90 +/- 0.28 ml.min-1.100 g body wt-1, P less than 0.01). Similar results were observed in LNC rats loaded with a K solution not containing Cl, but not in LNC rats loaded with a mixture of CaCl2, MgCl2, and HCl. In KCl-loaded LNC rats, cyclooxygenase inhibition decreased CIN from 0.49 +/- 0.09 to 0.30 +/- 0.08 ml.min-1.100 g body wt-1 (P less than 0.01). Aprotinin did not affect renal function despite significant decrease of UKALLV. We conclude that K loading prevents the decrease of GFR induced by captopril in Na-depleted rats and that this might be mediated by stimulation of glomerular prostanoid synthesis.

NaCl modulates captopril effects on glomerular prostaglandin synthesis and glomerular filtration

Captopril stimulates glomerular prostaglandin (PG) synthesis and increases glomerular filtration rate (GFR) in Na-repleted rats, whereas, in Na-depleted rats, it fails to stimulate PG synthesis and decreases GFR. In the present work the influence of chronic and acute NaCl loading on PG synthesis and renal function was studied in Na-depleted rats receiving captopril (LNC rats). Glomerular PGE2 and 6-keto-PGF1 alpha were not increased in LNC rats and were significantly lower than in Na-depleted rats (LN). Na repletion, while continuing captopril, increased PG synthesis above control levels. Addition of captopril in vitro to the incubation medium stimulated PGE2 synthesis in glomeruli of control rats, whereas it depressed it in LN rats. Acute loading with NaCl in LNC rats increased inulin and PAH clearances to values significantly greater than in control rats and similar to those of normal rats receiving captopril. Comparable volume loading with isotonic mannitol or 3% albumin increased inulin and PAH clearances only to control values. The specific effect of NaCl in acute loading was prevented by cyclooxygenase inhibition and was not mediated by increased systemic blood pressure. The results provide evidence that the effects of captopril on glomerular PG synthesis and renal function depend on the state of Na balance.

Captopril, but not diltiazem, favorably affects the course of early chronic renal disease in rats

The concepts that increased intracellular Ca2+ content and increased glomerular capillary pressure play an important role in the progression of chronic renal diseases has led to the suggestion that treatment with calcium-blocking agents (diltiazem; CBB) or converting enzyme inhibitors (captopril; CEI) may be indicated to prevent renal failure. We studied the effects of CCB and CEI on the early course of adriamycin (ADR) nephropathy, where glomerular pressure has been shown to be unchanged, blood pressure was only mildly elevated and renal failure incipient. Animals were studied 2, 7, 12, 16 and 20 weeks after the second injection of ADR, 2 mg/kg. In treated rats, blood pressure remained normal. At the end of the study, proteinuria and serum creatine were lower in ADR-CEI than in ADR rats (149 +/- 42 vs. 616 +/- 90 mg/day, p less than 0.01 and 0.36 +/- 0.04 vs. 0.58 +/- 0.02 mg%, p less than 0.01, respectively). ADR-CCB had values similar to those of untreated ADR rats. Mesangial expansion and focal glomerulosclerosis were present only in ADR and ADR-CCB rats, whereas in ADR-CEI rats the glomeruli were virtually normal. Glomerular 45Ca uptake was increased in ADR, decreased in ADR-CCB rats, and normal in ADR-CEI. Glomerular 6-keto PGF1 alpha and TxB2 were significantly increased in ADR rats, and both treatments decreased TxB2. The results suggest that endogenous angiotensin II is important for the early progression of glomerular injury toward renal insufficiency, while tissue Ca2+ accumulation may play an important role in more advanced phases.

Presence of an anti-viral factor in peritoneal dialysis effluent

Viral peritonitis is an exceptionally rare occurrence in peritoneal dialysis. In fact, up to now, only one case report has been documented in the literature. In a prospective study, peritoneal dialysis effluent (PDE) was specifically cultured for the following viruses: the herpes group of viruses, including herpes simplex types I (HSV) and II, cytomegalovirus (CMV) and varicella-zoster (V-Z), and the enteroviruses group including coxsackie B-5 (Cox B), echo, enterovirus and polio. Cultures were performed under both basal conditions and in the presence of peritonitis. No viral growth was demonstrated. The possible existence of an anti-viral factor in the PDE was therefore raised. In order to investigate this hypothesis, the PDE of 16 patients undergoing intermittent peritoneal dialysis and of 24 patients on continuous ambulatory peritoneal dialysis were examined for anti-viral activity. The method used was analogous to that employed for testing the anti-viral effect of interferon (IFN). The inhibition of the cytopathic effect (CPE) of various viruses was examined in the following tissue cultures: Vero cells (a line of monkey kidney cells) incubated with HSV, vesicular stomatitis virus (VSV) and Cox B; human kidney cells incubated with parainfluenza 3 (Para-3); human foreskin fibroblasts incubated with CMV, HSV and VSV and L-929 (a line of mouse cells) incubated with VSV. As control, unused Dianeal (Travenol, Ashdod, Israel) 1.5 and 4.25 g/dl, normal saline and 5 g/dl dextrose solutions were tested under the same conditions using VSV on Vero. The PDE was also examined for the presence of specific anti-viral antibodies by microneutralization and ELISA tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of sodium depletion on renal prostanoid synthesis in rats: influence of the converting enzyme inhibitor captopril

1. The synthesis of prostaglandin (PG) E2, PGF2 alpha, 6-keto-PGF1 alpha and thromboxane (TX) B2 by isolated glomeruli, cortical tubules, inner medullary slices and outer medullary slices was measured in salt-depleted (LNa) rats and in salt-depleted rats receiving captopril (LNa-CEI). Animals were studied before and after 4, 9 and 15 days of Na+ depletion. 2. Na+ balance was reached in LNa rats after 4 days. Blood pressure and creatinine clearance remained stable. Serum Na+ decreased from 140 +/- 1 to 126 +/- 1 mmol/l (mean +/- SEM, P less than 0.01). In contrast, LNa-CEI rats were unable to conserve Na+ adequately: fractional excretion of Na+ and natriuresis were constantly greater than in LNa animals. As a consequence, LNa-CEI rats developed severe hyponatraemia, lost weight and their creatinine clearance decreased. 3. The glomerular synthesis of PGE2, PGF2 alpha and 6-keto-PGF1 alpha, but not of TXB2, was significantly increased in LNa rats. In LNa-CEI rats, the synthesis of PGE2 and 6-keto-PGF1 alpha was similar to control values, but PGF2 alpha and TXB2 synthesis was elevated at day 9. In cortical tubules, PGE2 and PGF2 alpha were unaffected by Na+ depletion, but 6-keto-PGF1 alpha and TXB2 were increased and a similar trend was observed in LNa-CEI rats. In outer medulla of LNa rats, a decrease in all the eicosanoids measured was observed at day 4. In LNa-CEI animals, the synthesis of PGE2 and PGF2 alpha, but not of 6-keto-PGF1 alpha and TXB2, was significantly depressed. In inner medulla, Na+ depletion only tended to decrease PGF2 alpha and 6-keto-PGF1 alpha, but in the presence of captopril, the synthesis of all prostanoids was significantly decreased.

Thrombin inhibits the synthesis of prostanoids by isolated glomeruli and peritoneal macrophages in rats

Activation of macrophages and release of mediators that activate the coagulation system characterize proliferative glomerulonephritis. To evaluate the possible role of prostanoids in this process, isolated rat glomeruli (G) and peritoneal macrophages (M) or a combination of the two (G + M) were incubated in the presence of thrombin (2 U/ml). In G, thrombin inhibited only the synthesis of thromboxane B2. In M and G + M incubations, the synthesis of prostaglandin I2 and thromboxane A2 was inhibited by thrombin. This effect was abolished by the addition of arachidonic acid. As prostanoids may play a modulatory role in the interaction between macrophages and glomerular cells, inhibition of their synthesis by thrombin might enhance macrophage activity.

Endogenous digoxin-like factor raises blood pressure and protects against digitalis toxicity

Digoxin-like immunoreactive factor (DLIF) is an endogenous natriuretic material which causes diuresis and natriuresis after salt or fluid loading and which may play a pathogenetic role in various hypertensive states. In order to study the cardiovascular effects of DLIF, we administered partially purified material (500 ng/kg) iv to normal rats. DLIF administration caused a significant rise in blood pressure, induced a brisk diuresis, and slowed the heart rate. In addition, DLIF protected against digitalis toxicity. While iv digoxin, 1 mg/kg, uniformly produced lethal arrhythmias, administration of DLIF 15 min prior to digoxin infusion consistently protected against arrhythmias. These findings support the theory that DLIF may play a role in hypertension. In addition, DLIF may compete with digoxin for cardiac receptors.

Role of glomerular prostanoid in control of glomerular filtration rate in rats

It is generally accepted that the main action of glomerular prostanoids (GPs) on glomerular filtration rate (GFR) is to modulate the activity of different vasoconstrictors, specially in states of renal hypoperfusion. However it was also suggested that GPs may directly affect GFR. The present study was focused on this last hypothesis, in different experimental models, in rats. In adriamycin induced acute renal failure, the transient decrease of GFR is associated with higher levels of thromboxane B2. Later on, when GFR returns to normal, vasodilator prostaglandins synthesis was also increased. In captopril induced renal failure in Na depleted rats (where GPs synthesis remained normal), stimulation of PGE2 and PGI2 production by K and NaCl was associated with a significant improvement of GFR. Furthermore, the increase in GFR induced by NaCl was prevented by inhibition of prostaglandin synthesis. Infusion of atrial natriuretic peptide in euvolemic rats induce a marked elevation both of GFR and PGE2 synthesis. It was abolished by previous administration of prostaglandin synthesis inhibitor. In conclusion, glomerular prostanoids may influence GFR, either directly, or as mediator or modulator of other vasoactive hormones.

Transcutaneous monitoring of blood gas tensions in patients on intermittent peritoneal dialysis

A relative contraindication to intermittent peritoneal dialysis (IPD) is chronic lung disease. To evaluate whether the instillation of 2 L of fluid into the peritoneal cavity affects respiratory function, five IPD patients were studied in the supine position during the first 4 h of a routine IPD session. Blood gas tensions were monitored transcutaneously throughout the study period. At the onset of dialysis, mean transcutaneous blood oxygen tension (PtcO2) was 70.6 +/- 9.1 mm Hg. It decreased to 55 +/- 9.9 mm Hg (22% change from basal values) during the instillation of dialysate. Upon drainage, PtcO2 returned to baseline. This sequence of events repeated itself on subsequent exchanges, although with decreasing decrements of PtcO2 with each consecutive exchange (decrease to 58.6 +/- 7.05, 61 +/- 6.5, 63.8 +/- 5.2 mm Hg corresponding to 16%, 12.7%, and 9.6%, respectively, during the second to fourth exchanges). Transcutaneous blood carbon dioxide tension, PtcCO2, showed a very mild increase during the study (33 +/- 7.1 to 38 +/- 6.0 mm Hg). In two patients, the same study protocol was performed during the last 4 h of an IPD session. In these two patients, there was only a 5% variation of PtcO2 from baseline values. These results suggest that an adaptive response to the hypoxemia induced by dialysate instillation rapidly occurs in IPD patients.

Prostanoids in renal failure induced by converting enzyme inhibition in sodium-depleted rats

Clearances of inulin (CIn) and p-aminohippurate (CPAH) were measured in four groups of rats before and after intravenous administration of acetylsalicylic acid (ASA): 1) controls, on normal Na intake, 2) captopril-treated (30 mg.kg-1.day-1) on normal Na intake, 3) Na depleted, and 4) Na depleted, captopril-treated. In Na-depleted animals, CIn and CPAH were similar to controls but decreased significantly with ASA. In Na-depleted, captopril-treated rats, CPAH was slightly decreased, but CIn was significantly reduced (P less than 0.01). Both were not affected by ASA. Urine output was unchanged and the kidneys appeared normal on histological examination. The production of prostaglandins E2 (PGE2), F2 alpha (PGF2 alpha), and thromboxane B2 (TxB2) was measured in isolated glomeruli, cortical tubule suspensions, and medullary and papillary slices. Captopril increased PGE2 production by glomeruli and PGF2 alpha and TxB2 synthesis in papillary slices. Na depletion selectively enhanced the production of PGE2 by glomeruli and papillae. In contrast, the synthesis of prostanoids was significantly decreased in captopril-treated, Na-depleted rats. These findings suggest that in this model, functional nonoliguric renal failure may be related to abnormalities of prostanoid synthesis.

Atrial natriuretic peptide administration to normal and salt depleted rats--effects on digoxin-like immunoreactive factor, aldosterone, ACTH, and renal function

In view of the known interrelationships between renin, aldosterone, and atrial natriuretic peptide (ANP), we sought to examine whether there also exists an interaction between ANP and digoxin-like immunoreactive factor (DLIF). We therefore studied the effects of ANP administration on normal and salt-depleted rats, and measured the effects on blood pressure, urine output, glomerular filtration rate, sodium excretion, aldosterone, ACTH, and DLIF levels. ANP administration resulted in a significant elevation of sodium excretion and glomerular filtration rate and a fall in blood pressure. DLIF concentrations in plasma rose significantly, as did urinary DLIF excretion. ANP administration resulted in a fall in aldosterone as well as ACTH. These observations suggest that ANP has a direct inhibitory effect on ACTH secretion. Our findings support the concept of an interrelationship between ANP and DLIF.

Increased drainage volume in intermittent peritoneal dialysis using a two-bag, low hydrostatic pressure drainage system

Adequate drainage volume (DV) is a prerequisite for long-term success of intermittent peritoneal dialysis (IPD). Ultrafiltration (UF) is basically determined by the interplay of two major forces: a driving osmotic force created by a hyperosmolar dialysate solution versus an opposing force--the intraperitoneal hydrostatic pressure. Conventional drainage procedures (CS) are capable of achieving a fluid volume of 3 L per bag. We found that this intrabag volume corresponds to an intrabag hydrostatic pressure of 60 cm water. Because this drainage system is closed, the intrabag hydrostatic pressure reflects intraperitoneal hydrostatic pressure. A low-pressure system (LPS) was devised to evaluate the possible influence on DV of reducing HP. Our results show that such LPS does indeed significantly improve DV, using a decreased number of exchanges. The residual volume and its glucose concentration (in a 1.5-g/dl exchange) were measured with CS. When followed by an 4.25-g/dl exchange, an 11% reduction in glucose concentration was evident. Thus, the osmotic driving force may also be impaired by incomplete drainage. To obtain maximal DV during IPD, a LPS should be used. This could be achieved by using 2 L dialysate in 3-L bags.

Acute glomerulonephritis secondary to lobar pneumonia

We report 4 cases of children who developed lobar pneumonia and subsequently acute glomerulonephritis, all within a period of six weeks. In one case streptococcus pneumonia type 5 was isolated, a strain not previously described in the literature as being nephritogenic.

Intestinal fat malabsorption in the uremic rat

In the past we have shown that patients with chronic renal failure (CRF) on hemodialysis show evidence of intestinal malabsorption of fat. The present study was designed to verify this finding in an animal model. Male rats weighing +/- 200 g were studied. Uremia (U) was induced by 2-stage subtotal (5/6) nephrectomy. Control (C) animals were sham-operated. Fat absorption was studied after 6 weeks of uremia with the oral fat loading test. Twenty percent intralipid (0.25 g/100 gBW) was given by gastric tube feeding to fasting animals and the appearance of chylomicrons (CHYL) and the rise of triglycerides (TG) in the serum was followed for 5 hrs. In order to isolate the effect of fat absorption, an additional group of U and C animals was pretreated with orotic acid and triton, thus blocking hepatic TG synthesis and neutralizing peripheral lipoprotein lipase activity. The absorption of CHYL was significantly (p less than 0.01) impaired in all U animals and averaged 43 and 70 percent of that of the C animals, 1 and 2 hrs after the load respectively. The rise in serum TG did not differ from C in mildly U animals (Scr 1.0 +/- 0.04). In the more severely uremic animals (Scr 2.6 +/- 0.2), however, pretreated with orotic acid and triton, the rise in serum TG was far less (p less than 0.01) than in C animals (111 +/- 26-903 +/- 111 delta % V.780 +/- 170-5032 +/- 746 delta %) 1 and 5 hrs after the load.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased renal threshold of bicarbonate due to carbon dioxide retention associated with proximal renal tubular acidosis

We report a neonate who manifested type II (proximal) renal tubular acidosis (RTA). Hypoventilation secondary to hypothalamic dysfunction led to carbon dioxide retention. The consequent changes in acid base regulation are detailed and discussed.

Hypercalcaemia-induced acute renal failure as a presenting feature of T-cell leukaemia

A 14-year-old patient presented with hypercalcaemia-induced acute renal failure. Investigation yielded a diagnosis of T-cell leukaemia. Chemotherapy resulted in complete remission, a return of serum calcium levels to normal and consequent improvement of renal function.

IgM nephropathy: morphological study related to clinical findings

This study describes 10 cases of IgM nephropathy in whom the main morphological findings consisted of diffuse mesangial deposition of IgM and varying degrees of mesangial cell proliferation. In addition, focal segmental sclerosis was present in 1 patient and global sclerosis in another. An ill-defined electron-dense deposit was seen within the mesangial area in 1 case. Except for 1 patient, who had hematuria only, all suffered from nephrotic syndrome without deterioration of renal function. In view of the constant and characteristic finding of a diffuse mesangial IgM deposition, it is suggested that this form of nephropathy constitutes an entity separate from focal glomerulosclerosis or minimal change disease.

Natriuretic response to i.v. saline loading after acute poststreptococcal glomerulonephritis

The outcome of acute poststreptococcal glomerulonephritis (APSGN) is still controversial. Whereas many studies show a good prognosis, particularly in children, late morphologic and functional renal abnormalities have been described. To verify this latter finding, we evaluated the sodium handling of the kidney several years after APSGN. Eleven subjects (9 children and adolescents and 2 adults) were studied 2 to 3 years after APSGN. At the time of the study all patients were well, without pathologic urinary findings and with normal blood pressures. Five healthy subjects (3 adults and 2 children) served as controls. Following two control periods of 30 min, an i.v. saline load (2.5% NaCl, 1 l/1.73 m2 body surface area) was administered over 45 min. Sodium excretion was measured during the control and salt-loading periods, and during four additional 30-min collection periods. No exaggerated natriuresis was found. We therefore conclude that epidemic APSGN in Israel carries not only an excellent clinical but also a good renal functional prognosis.