[The effect of the preparation Wobe-Mugos E on the functional and biochemical status of the kidneys in the polyuric stage of sublimate-induced nephropathy]

The protective effect of Wobe-Mugos appliance on the kidney function and biochemical state in polyuric stage of sublimate nephropathia at the moment of tubulointerstitial component formation was revealed in experiments on 40 white male rats. It appeared in the increase of hydrogenous ion excretion, titred acids, renal tissue fibrinolytic and proteolytic activity. The succinatdehydrogenase activation in renal cortex matter pointed out on the improvement of energy balance.

Activation of hypothalamic neuronal nitric oxide synthase in lithium-induced diabetes insipidus rats

The expression of the neuronal nitric oxide synthase (nNOS) gene in the paraventricular (PVN) and supraoptic nuclei (SON) in rats with lithium (Li)-induced polyuria was examined by using in situ hybridization histochemistry. The state of the thyroid axis in these rats was also examined by in situ hybridization histochemistry for thyrotropin-releasing hormone (TRH) and thyroid-stimulating hormone (TSH) mRNAs and radioimmunoassay for circulating thyroid hormones. Adult male Wistar rats consuming a diet that contained LiCl (60 mmol/kg) for 4 weeks developed remarkable polyuria. The urine in the Li-treated rats was hypotonic and had a large volume and low ionic concentration. The nNOS mRNA in the PVN and SON was significantly increased in the Li-treated rats in comparison with that in control. The increased levels of the nNOS mRNA in the PVN and SON were confirmed by NADPH-diaphorase histochemical staining. There were no differences of TRH mRNA in the PVN, TSH mRNA in the anterior pituitary and plasma concentrations of free T3 and free T4 between Li-treated rats and control rats. These results suggest that Li-induced diabetes insipidus may activate nNOS in the PVN and SON without change of the thyroid axis.

Expression of renal aquaporins 1, 2, and 3 in a rat model of cisplatin-induced polyuria

BACKGROUND

Cisplatin (CP)-induced polyuria in rats is attributed to decreased medullary hypertonicity and/or an end-organ resistance to vasopressin. However, the roles of renal aquaporins (AQPs) have not yet been explored.

METHODS

Male Sprague-Dawley rats (230 to 245 g) received either a single injection of CP (5 mg/kg, N = 4) or saline (N = 4) intraperitoneally five days before sacrifice. Urine, blood, and kidney samples were analyzed.

RESULTS

Platinum accumulated in the cortex and outer medulla of CP-treated rats (39.05 +/- 7.50 and 36.48 +/- 12.44 microg/g vs. 2.52 +/- 0.43 and 1.87 +/- 0.84 microg/g dry tissue in controls, respectively). Histologically, tubular damage and decreased AQP1 immunolabeling were detected in the S3 segment of proximal tubules. CP treatment caused 4.4- and 4.8-fold increases, respectively, in blood urea nitrogen and urine volume, and a 4. 4-fold decrease in urine osmolality. Immunoblots showed that AQP2 and AQP3 were significantly reduced to 33 +/- 10% (P < 0.001) and 69 +/- 11% (P < 0.05), respectively, in the inner medulla of CP-treated rats. Immunocytochemical analysis showed a decrease in AQP2 labeling in the inner medulla of CP-treated rats. Northern hybridization revealed a 33 +/- 11% (P < 0.002) decrease in AQP2 mRNA expression in the inner medulla of CP-treated rats. AQP1 protein expression levels were modestly (67 +/- 7%, P = 0.057) and significantly (53 +/- 13%, P < 0.007) decreased in outer and inner medullae, respectively, of CP-treated rats.

CONCLUSIONS

CP-induced polyuria in rats is associated with a significant decrease in the expression of collecting duct (AQP2 and AQP3) and proximal nephron and microvascular (AQP1) water channels in the inner medulla.

The protective effect of taurine against gentamicin-induced acute tubular necrosis in rats

BACKGROUND

Taurine, which is the major intracellular free beta-amino acid, is known to be an endogenous antioxidant and a membrane-stabilizing agent. In this study, we wished to know whether taurine altered the concentration of gentamicin in kidney tissue and could protect against gentamicin-induced acute proximal tubular injury.

METHODS

Wistar albino rats of both sexes were assigned to three groups, which all received one of the following daily intraperitoneal injections for 8 days: (i) 0.9% sodium chloride (NaCl) alone at the same volume as gentamicin treated rats (group C; n=8); (ii) 100 mg/kg/day gentamicin alone (group G; n=8, four male, four female); or (iii) 100 mg/kg/day gentamicin plus 7.5 ml/kg/day taurine (group G+T; n=9, five male, four female). Urine was collected for 24 h for the determination of urine volume and creatinine. Intracardiac blood was collected for blood urea nitrogen (BUN) and serum creatinine determination. The kidneys were removed, weighed, and the left kidneys were subjected to biochemical analysis for the determination of thiobarbituric acid-reactive substance (TBARS) and lactate levels, and glutathione peroxidase (Gpx) and superoxide dismutase (SOD) activities. The right kidneys were divided vertically in half. The upper halves were used for histopathological examination, by light and electron microscopy. The lower halves were used to detect the gentamicin concentration within the kidney tissue, by high-performance liquid chromatography (HPLC). Changes in body weight and normalized kidney weight were recorded.

RESULTS

Taurine treatment reduced gentamicin-induced increases in serum creatinine, 24 h urine volume, BUN and tissue lactate and TBARS levels (0.57+/-0.02 vs 1.06+/-0.08 mg/dl, P<0.001; 9.00+/-1.46 vs 20.9+/-2.73 ml, P<0.001; 25.3+/-1.87 vs 54.1+/-6.99 mg/dl, P<0. 001; 2.56+/-0.10 vs 3.44+/-0.08 micromol/g wet tissue, P<0.001; and 66.4+/-3.41 vs 79.5+/-5.07 nmol/g wet tissue, P>0.05, respectively). Taurine reduced the accumulation of gentamicin within the kidney tissue (233+/-29 vs 494+/-93 microg/g wet tissue, P<0.05). Taurine treatment also prevented body weight loss due to gentamicin administration (17.8+/-1.64 vs -10.0+/-7.08 g, P<0.01) and normalized reduced Gpx and SOD activities (3.46+/-0.16 vs 2.37+/-0. 15 U/g wet tissue, P<0.01; and 15577+/-377 vs 12662+/-577 U/g wet tissue, P<0.01, respectively). Light microscopic examination of the renal tissues from gentamicin-treated rats revealed severe histopathological changes, whereas specimens obtained from taurine-treated rats revealed only mild changes. This finding was supported by electron microscopic examination.

CONCLUSIONS

Our observations suggest that taurine treatment attenuates the accumulation of gentamicin within kidney tissue and counteracts the deleterious effect of gentamicin on renal tubular function. They may have potentially important clinical implications.

[Drug-induced polyuria in the surgical treatment of patients with nephrolithiasis]

Recently, drug polyuria has found wide application in diagnosis and treatment: to detect latent urinary insufficiency, to assess functional performance of the contralateral (unaffected) kidney in nephrolithiasis and calculous pyelonephritis, to stimulate elimination of fragments of the disintegrated concrement, to check up suture impermeability after surgical repair of the urinary tracts, to outline afunctional zone in hydronephrosis. Clinical experience gives grounds for use of saluretics at certain stages of pyelolithotomy for mobilization of intrarenal pelvis and its dissection, removal of the calculus and subsequent suturing of the intrarenal pelvis. Therapeutic polyuria can also facilitate ureterolithotomy.

Dehydration reverses vasopressin antagonist-induced diuresis and aquaporin-2 downregulation in rats

To examine the involvement of vasopressin and dehydration in the regulation of aquaporin-2 (AQP2) expression in rat kidney, we investigated the effects of treatment for 60 h with the specific V2-receptor antagonist OPC-31260 (OPC), alone and in conjunction with dehydration for the last 12 h. Changes in AQP2 protein and mRNA expression in kidney inner medulla were determined by Western and Northern blotting, and AQP2 distribution was analyzed by immunocytochemistry and immunoelectron microscopy. Treatment with OPC increased urine output fourfold, with a reciprocal decrease in urine osmolality. AQP2 expression decreased to 52 +/- 11% of control levels (n = 12, P < 0.05), and AQP2 was found predominantly in intracellular vesicles in collecting duct principal cells. This is consistent with efficient blockade of the vasopressin-induced AQP2 delivery to the plasma membrane and with the observed increased diuresis. Consistent with this, AQP2 mRNA levels were also reduced in response to prolonged OPC treatment (30 +/- 10% of control levels, n = 9). Five days of treatment with furosemide, despite producing even greater polyuria than OPC, was not associated with downregulation of AQP2 levels, demonstrating that AQP2 downregulation is not secondary to increased urine flow rate or loss of medullary hypertonicity. During 12-h thirsting in the continued presence of OPC, urine output dropped dramatically, to levels not significantly different from that seen in (nonthirsted) control animals. In parallel with this, AQP2 levels rose to control levels. Control experiments confirmed continued effective receptor blockade. These results indicate that the V2-receptor antagonist causes a modest decrease in AQP2 expression that is not a consequence of increased urine flow rate or washout of medullary hypertonicity. However, this decrease is much less marked than that seen in some forms of acquired nephrogenic diabetes insipidus. In conjunction with the effects of thirsting, this suggests that modulation of AQP2 expression is mediated partly, but not exclusively, via V2 receptors.

Renal side-effects of long-term lithium treatment

The beta 2-Mg (beta 2-microglobulin) and GAG (glycosaminogyclan) excretions in 107 patients with bipolar disorder who had been on lithium treatment for 1-15 years were compared with 29 matched psychiatric control patients. 24-h urine volume, urine beta 2-Mg, GAG values were significantly higher, and maximal urinary osmolality was significantly lower in patients on lithium than in controls. No relationship was found between creatinine clearances and duration of illness, duration of lithium treatment and daily lithium dosages. Duration of lithium treatment was not related to the concentrating capacity. The beta 2-Mg excretion rates were significantly higher in patients with manifest polyuria and with severe concentration defect.

Suppression of herpes simplex virus infections with oral lithium carbonate--a possible antiviral activity

In vitro studies have shown an inhibitory effect of lithium salts on herpes simplex virus (HSV) replication by mechanisms that interfere with viral DNA synthesis. Moreover, clinical studies have shown that oral lithium carbonate and topical lithium succinate can suppress genital HSV infections in humans. We conducted a randomized, double-blind, placebo-controlled trial of oral lithium carbonate in 11 healthy subjects age 28-65 years (mean +/- SD age 38 +/- 11 years) who had at least four recurrent HSV infections in the year preceding the study. Six patients completed at least 5 months of lithium therapy at a mean (+/-SD) average daily lithium dose of 437 +/- 185 mg (range, 150-900 mg) and an average serum lithium level of 0.56 +/- 0.20 mmol/L. Overall, lithium treatment resulted in a consistent reduction in the mean number of episodes/month, the average duration of each episode, the total number of infection days/month, and the maximum symptom severity. In contrast, treatment with placebo resulted in an increase in three out of the four severity measures. Although the comparisons between the treatment groups did not achieve statistical significance due to the limited sample size, there was a clear "trend" for a reduction in the total monthly duration of all HSV infections with lithium (p = 0.08). Lithium treatment was well tolerated and produced no deleterious effects on renal or thyroid function. These observations lend support to prior observations of an antiviral activity of lithium, and suggest the possibility that oral lithium may represent a safe prophylactic agent in patients with recurrent HSV infections.

Mechanism of lithium-induced polyuria in the rat

While many studies have demonstrated a nephrogenic diabetes insipidus syndrome (NDI) with prolonged lithium (Li) treatment, experiments in the isolated rat papillary collecting duct have suggested that the defect may be due to a circulating factor that inhibits the action of arginine vasopressin (AVP). Since Li-treatment can produce a form of hyperparathyroidism and parathyroid hormone (PTH) can act as a partial agonist to AVP, in vivo and in vitro studies were performed on rats made polyuric by daily intraperitoneal (i.p.) Li (4 mmol/kg) treatment. Li-treatment for three weeks produced an increase in PTH (194 +/- 20 compared with 118 +/- 18 pg/ml in control rats; P < 0.01) as well as an increase in the plasma calcium concentration (2.38 +/- 0.05 compared with 2.25 +/- 0.04 mmol/liter; P < 0.05). Clearance studies were performed on water loaded Li-treated and control rats, and the defect in urine concentration was only observed with a low physiological concentration of AVP (10 mU/kg body wt over 5 min). Maximal urine osmolality was 328 +/- 31 compared with 613 +/- 81 mOsm/kg (P < 0.05) in controls. There was no detectable difference with a prolonged maximal physiological AVP concentration (10 mU bolus and 50 mU/kg body wt per hr) and papillary solute concentrations were unchanged. When Li-treated rats had been parathyroidectomized (PTX), a significant difference in urine concentration with the low AVP concentration could not be demonstrated when compared to non-PTX control rats. In the isolated papillary collecting duct preparation a medium was used that contained fresh plasma from Li-treated or control rats, both intact and PTX. Experiments using plasma from Li-treated intact rats produced only a 25.4 +/- 5.1% increase in diffusional water permeability with the addition of AVP (200 microU/ml) compared to 52.6 +/- 9.0% in control rats (P < 0.01). However, when plasma from Li-treated PTX rats was used, the AVP induced increase in water permeability (54.7 +/- 11.2%) was not significantly different from that observed in PTX control rats. These studies show that the NDI-like defect in Li-treatment is small and easily overcome by higher concentrations of AVP and suggests that the concentration defect is at least in part due to increased circulating levels of PTH acting as a partial agonist to AVP and thereby inhibiting its hydroosmotic action.

Evidence for circulating vasopressin-like peptides in a case of polyuria

Plasma immunoreactive vasopressin (iAVP) was studied by RIA in a patient suffering from polyuria during chronic treatment with lithium. The combined use of two antisera specific for different regions of the AVP molecule allowed us to detect circulating forms which are modified in the acyclic tripeptide portion. In this lithium-treated patient, iAVP was abnormally low with respect to plasma osmolality. However, iAVP increased during hypertonic saline infusion, probably through an osmosensitive mechanism. A remarkable finding was that contrary to the observations made in healthy subjects and in another patient with diabetes insipidus, iAVP measured with the antiserum specific for the acyclic portion of the AVP molecule was below the values measured with the antiserum specific for the hexapeptide ring. This unusual immunoreactivity profile suggests that the plasma of this polyuric lithium-treated patient contains vasopressin-like peptides which differ from arginine vasopressin in the structure of the C-terminal tripeptide tail.

Lithium induced polyuria and renal vasopressin receptor density

BACKGROUND

Lithium, a drug frequently used for treatment of affective disorders, is known to cause a vasopressin-resistant state, leading to polyuria and polydipsia. It has been suggested that lithium interacts with the renal V2-vasopressin receptor. Detailed studies on the influence of lithium on the AVP receptor, however, have so far been difficult due to the lack of a suitable radioligand with high specific activity and high affinity.

METHODS

Using 125I-[8-(p-(OH)-phenylpropionyl)]- LVP, we studied the effects of lithium on V2-vasopressin receptors in male Sprague-Dawley rats and LLC-PK1 cells. Rats, having free access to water, were orally treated with 10 mg lithium/100 mg b.w./day or placebo for 10 days. Scatchard analysis was performed using membranes prepared from homogenized renal papillae.

RESULTS

Lithium caused significant polyuria and an impaired renal concentration capacity after water deprivation. Binding studies showed no effect of lithium on binding affinity KD (0.98 +/- 0.21 nmol/l vs. 0.86 +/- 0.15 nmol/l (Li) (n.s.). Receptor density, however, significantly decreased from 130 +/- 12.3 nmol/kg protein in controls (n = 8) to 101.7 +/- 13.4 nmol/kg protein (n = 8), (P < 0.05). Plasma osmotically and AVP were not significantly altered by lithium treatment. Vasopressin receptor density on LLC-PK1-cells, a pig renal cell line, was not changed by preincubation with lithium (312 +/- 22 nmol/kg vs. 329 +/- 25 nmol/kg (Li) (n = 6, n.s.).

CONCLUSIONS

The decrease of AVP-receptor density in vivo might be related to vasopressin resistance, either primary, or secondary to other factors, e.g. actual water transport.

Responses of the renal prostanoids to a short-term depletion of sodium or potassium in healthy women

The short-term effects of extracellular fluid volume depletion on the generation of some bioregulators of the renal function have been studied in healthy women. Eight subjects (SD group) were submitted to a low NaCl dietary intake and natriuretic treatment. At the end of the treatment (6 days) a cumulative sodium deficit of 381 +/- 55 mmol (mean +/- SEM) and a body weight variation of -2.1 +/- 0.28 kg were estimated. The renal function was explored by clearance method during hypotonic polyuria induced by oral water load and subsequent antidiuresis induced by low-dose infusion of lysine-8-vasopressin. The basal values of plasma renin activity were determined just before the water load as well as the urinary aldosterone excretion of the foregoing 24 hours was. During the renal functional exploration the urinary concentrations of PGE2, 6-keto-PGF1 alpha (6KPGF) and TxB2 were determined by RIA method. We report also, as comparison terms, the results obtained either in potassium depletion (KD group, n = 12) or in normal sodium and potassium balance (N group, n = 20). 1) In the SD vs N group-besides the increase in renin and aldosterone secretion-the behaviour of urinary prostanoids is consistent with a stimulation of the renal synthesis of PGI2 and TxA2 as well as of PGE2, at least as a trend. 2) In the KD vs N group an increase in renin secretion occurred while the urinary aldosterone was not significantly decreased. The urinary prostanoid data suggest an inhibition of the renal synthesis of PGE2 and PGI2. All three urinary prostanoids were significantly lower in the KD as compared to the SD group. Thus, in salt depletion the renal prostanoid synthesis was enhanced while it was depressed in potassium depletion, despite the increased renin secretion.

Interactions between acute effect of angiotensin converting enzyme inhibition and salt balance on the renal function and urinary prostanoids. Studies in healthy women

The acute effects of angiotensin converting enzyme inhibition on the renal function and urinary prostanoids were studied. Healthy women were studied in both sodium depletion (n = 8) and normal balance of sodium and potassium (n = 6). Each woman underwent paired renal functional explorations (by the clearance method during hypotonic polyuria and subsequent antidiuresis) in the absence and in the presence of enalapril. In both experimental conditions enalapril failed to affect urinary prostanoid excretions. Only in the presence of hyperreninemia induced by salt depletion, enalapril was effective in inducing renal tubular effects only partly consistent with a depressed activity of angiotensin-aldosterone system. Specifically, in sodium depletion enalapril treatment promoted a decreasing trend in urinary salt excretion, dependent in turn on selective stimulation of the distal tubule NaCl transport. Furthermore, plasma potassium concentration was reduced despite the concomitant decrease in urinary potassium excretion.

Verapamil-induced "primary" polydipsia

An 11-month-old male infant with recurrent supraventricular tachycardia (SVT) was treated with oral verapamil. Shortly thereafter he developed marked changes in behavior including lethargy, intensely increased thirst and urination, and irritability when denied fluids. "Primary" polydipsia was diagnosed following an evaluation which showed no evidence of adrenal insufficiency, diabetes insipidus, diabetes mellitus, hypercalcemia, hyperosmolality, or renal disease. The symptoms resolved 1 week after verapamil was discontinued.

Lithium-induced downregulation of aquaporin-2 water channel expression in rat kidney medulla

Lithium, a widely used treatment for bipolar affective disorders, often causes nephrogenic diabetes insipidus. The effect of chronic lithium therapy on the expression of the vasopressin-regulated water channel Aquaporin-2 (AQP2) in rat kidney was examined. Membranes were prepared from inner medulla of one kidney from each rat, while the contralateral one was fixed for immunofluorescence and immunoelectronmicroscopy. Immunoblotting revealed that lithium treatment reduced AQP2 expression dramatically, to 31 +/- 8% after 10 d and to 4 +/- 1% after 25 d, coincident with development of severe polyuria. Immunofluorescence and immunogold quantitation confirmed the lithium-induced decrease in AQP2 expression (from 11.2 +/- 1.0 to 1.1 +/- 0.2 particles/microns 2). The downregulation was only partly reversed by return to lithium-free diet for 1 wk (40 +/- 8% of control). Furthermore, immunoblotting and immunogold quantitation revealed that 2 d of thirsting or 7 d of dDAVP treatment, in the continued presence of lithium, increased AQP2 expression by six- and threefold, respectively, coincident with increased urinary osmolality. Thirsting increased AQP2 immunolabeling mainly of vesicles, whereas dDAVP caused accumulation of AQP2 predominantly in the subapical region and plasma membrane. Thus, lithium causes marked downregulation of AQP2 expression, only partially reversed by cessation of therapy, thirsting or dDAVP treatment, consistent with clinical observations of slow recovery from lithium-induced urinary concentrating defects.

Massive vasopressin-resistant polyuria induced by dexamethasone

A case of severe polyuria elicited by intravenous administration of a normal pharmacological dose of dexamethasone is reported. The polyuria did not respond to treatment with vasopressin. A 15-year-old girl with a brain tumour was referred for surgery. After induction of anaesthesia she received dexamethasone 4 mg i.v., and developed a massive polyuria with hourly diuresis of up to 1250 ml. There was no response to treatment with vasopressin in doses well above those normally used. The patient did not fulfil any known cause of diabetes insipidus, and to our best knowledge, this case is the first with glucocorticoid-induced and vasopressin-resistant polyuria ever reported in man.

Manic depressive disorder and lithium over the decades: the very educational case of Mrs. L

BACKGROUND

Manic depressive disorder is a recurrent illness with a variable clinical course. Before the advent of modern pharmacotherapy, ECT was a common treatment; more recently, lithium has become the long-term treatment of choice, but it is a treatment that is not without complications.

METHOD

The psychiatric and medical history of an 80-year-old patient was reviewed and analyzed based on clinical interview and medical records. The findings were integrated with literature review to illustrate a number of important clinical points about manic depressive disorder and its treatment.

RESULTS

(1) ECT is an effective treatment for mania, (2) a sustained remission may occur spontaneously, (3) a mania-depression-euthymia episode sequence predicts favorable response to lithium, (4) lithium discontinuation is not without risk, (5) lithium continuation is not without risk (thyroid, kidneys, eyes).

CONCLUSION

The case of Mrs. L illustrates the longitudinal course of manic depressive disorder and how it can be influenced by treatment and withdrawal of treatment. It also illustrates the potential of lithium for causing adverse effects on several organ systems.

Abnormalities of coagulation in experimental nephrotic syndrome

The human nephrotic syndrome is accompanied by important alterations of the coagulation system related proteins. The purpose of the present study was to examine the activity of coagulation- and fibrinolysis-related proteins in plasma and urine of control and puromycin aminonucleoside injected rats on days 2 (prenephrotic stage) and 10 (nephrotic stage). We measured the prothrombin time (PT), the activated partial thromboplastin time (aPTT), and the activities of (1) the coagulation factors (CFs) I, II, V, and VII-XII; (2) the inhibitor of coagulation antithrombin III (ATIII), and (3) the component of the fibrinolytic system alpha 2-antiplasmin (alpha 2-APL). PT and aPTT and the activities of CF, ATIII, and alpha 2-APL were not measurable in the urine of control and puromycin amino-nucleoside injected rats on day 2. On this same day, plasma ATIII and CF VIII decreased. On day 10 (1) PT and aPTT decreased in plasma and were not measurable in urine; (2), plasma CFs I, II, V, VII, VIII, X, and XI increased; (3), plasma ATIII decreased; (4), plasma CFs IX and XII and alpha 2-APL did not change, and (5) ATIII and CFs II, VII, VIII, IX, X, XI, and XII, but not CFs I and V and alpha 2-APL, appeared in urine on day 10. ATIII deficiency was secondary probably to the urinary losses; however, the plasma activity of CFs II, VII, VIII, X, and XI increased and that of CFs IX and XII remained unchanged in spite of their urinary losses which suggests that other mechanisms such as deranged catabolism and altered hepatic synthesis may be involved.(ABSTRACT TRUNCATED AT 250 WORDS)

The consulting psychiatrist and the polydipsia-hyponatremia syndrome in schizophrenia

OBJECTIVE

The authors seek to extend understanding and treatment of hospitalized schizophrenics presenting with complications of polydipsia and dilutional hyponatremia. Attending physicians may ask the consultation/liaison psychiatrist to see schizophrenics with hyponatremically-induced delirium or other psychiatric syndromes. The referring physician may or may not have identified polydipsia and dilutional hyponatremia and their complications. This article will help the consultation/liaison psychiatrist recognize early evidence of water imbalance, describe evaluation, and provide somatic and behavioral treatment approaches to this life-threatening syndrome.

METHOD

Over the past ten years, the authors have treated more than 100 patients with the polydipsia-hyponatremia syndrome. The authors discuss their and others' experience with drugs that help and hinder patients suffering from dilutional hyponatremia. They review current key articles from the polydipsia-hyponatremia syndrome literature including articles identified via Medline search 1985-94.

RESULTS

Schizophrenics with the polydipsia-hyponatremia syndrome most commonly present with polydipsia, polyuria, urinary incontinence, cognitive, affective, and behavioral changes, seizures, or coma. Quantitating polydipsia, hyponatremia, and diurnal changes in body weight facilitate therapeutic interventions. Treatment include patient and caregiver education, drug therapies to better treat psychosis and better treat osmotic dysregulation, behavioral interventions to interdict polydipsia, and diurnal weight monitoring.

CONCLUSIONS

Once recognized, acute, subacute, and chronic complications of the polydipsia-hyponatremia syndrome are readily treatable. Besides treating the patient, consultation/liaison psychiatrists can teach their medical colleagues about this syndrome. In so doing, they will enhance the quality of their patients' lives and help the internist and surgeon feel more comfortable when working with schizophrenics.

Synergistic effects of anti-gp330 and anti-dipeptidyl peptidase type IV antibodies in the induction of glomerular damage

Passive Heymann nephritis (PHN) in the rat is induced by the administration of heterologous antibodies to renal tubular epithelium (RTE). The nephritogenic capacity of anti-RTE resides primarily in the antibody fraction directed against a 330-kD glycoprotein (gp330). However, monospecific anti-gp330 antibodies are less nephritogenic than anti-RTE antibodies. This discrepancy led us to study a possible synergizing role for different antibody specificities present within anti-RTE. The enzyme dipeptidyl peptidase type IV (DPP IV) is, like gp330, present in RTE as well as in the glomerulus. Anti-DPP IV antibodies have been shown to induce an acute, transient proteinuria. In this study, we investigated the nephritogenic effect of separate or simultaneous administration of heterologous anti-DPP IV and anti-gp330 antibodies. Injection of anti-DPP IV antibodies resulted in a short-lived glomerular binding, and in a dose-dependent polyuria, albuminuria or proteinuria. Binding of anti-gp330 antibodies was slower, but much more stable. Albuminuria could only be observed in the heterologous phase. Combined injection did not alter antibody-binding kinetics of either antibody nor the albuminuria induced by anti-gp330. However, in the presence of anti-gp330 antibodies, a lower dose of anti-DPP IV was capable to induce transient albuminuria as compared to anti-DPP IV alone. In conclusion, anti-DPP IV and anti-gp330 antibodies bind to different sites in the glomerulus with different kinetics. The presence of anti-gp330 deposits facilitated anti-DPP-IV-induced renal injury.