The clinicopathological characteristics of IgA nephropathy in Hong Kong

The clinicopathologic data of 237 Chinese patients with IgA nephropathy from Hong Kong are reviewed in an attempt to identify the features pertinent to Chinese patients. Although the nephropathy is commonest in the 26-35 year age group, 11% of the IgA nephritic patients were children below 16 years. The male predilection reported in Caucasian populations is not observed and the male:female ratio is 0.94 in our series. The commonest renal manifestation is microscopic hematuria (25%) and 19% of the patients present with macroscopic hematuria, not infrequently synpharyngitic. Nephrotic syndrome occurs in 15% of our patients and proteinuria more than 1 gm/day is documented in 58% of these IgA nephritic patients. The degree of proteinuria does not correlate with prognosis. A small proportion of these nephrotic patients respond to steroid therapy, suggesting a variant of IgA nephropathy that resembles lipoid nephrosis in its steroid-responsiveness. Seventeen percent of the patients (18/104) are hepatitis B virus carriers and 61% of these patients demonstrate viral antigens in their renal biopsies, indicating that hepatitis B virus infection may sometimes play a pathogenetic role.

CD4-positive cells from patients with IgA nephropathy demonstrate increased mRNA of cytokines that induce the IgA switch and differentiation

IgA nephropathy (IgAN) is characterized by raised serum IgA1 and mesangial IgA1 deposits. We have previously shown increased T-cell activation in IgAN. Recently, transforming growth factor-beta (TGF-beta) has been shown to induce IgA isotype switch at a clonal level and interleukin 5 (IL5) promotes differentiation into IgA-bearing B cells. In the present study we have examined the TGF-beta and IL5 mRNA expression by mitogen-activated CD4-positive T cells from patients with IgAN (n = 25), patients with other primary nephritides (CGN) (n = 24), and healthy control subjects (n = 25). The cytokine genes were analysed by reverse transcription (RT)-polymerase chain reaction (PCR) and were semi-quantitated by normalizing the differences occurring during RT and PCR using a housekeeping gene, beta-actin. CD4-positive T cells from IgA nephritic patients expressed a higher level of IL5 mRNA than healthy controls (P < 0.01) and patients with CGN (P < 0.005). CD4-positive T cells from IgA nephritic patients expressed a higher level of TGF-beta mRNA than healthy controls (P < 0.01) but no difference was demonstrated on comparison with CGN patients. Elevated TGF-beta mRNA expression in patients with CGN probably reflects its other important function as a 'sclerogenic' factor involved in the glomerulosclerosis found in these nephritides. Our data suggest that there is increased expression of cytokine genes which induce the IgA isotype switch and differentiation; these immunological abnormalities may be important in the pathogenesis of IgAN.

Mechanism of interference by hemoglobin in the determination of total bilirubin. I. Method of Malloy-Evelyn

Oxyhemoglobin is the species of hemoglobin in erythrocyte hemolysates that inhibits the diazo reaction. Ferric hemoglobin derivatives and species with relatively low molecular mass do not interfere. Conversion of oxyhemoglobin to acid hematin under assay reaction conditions is associated with rapid destruction of bilirubin, which accounts for the diazo reaction error. The most probable mechanism for this destruction of bilirubin is an oxidative reaction involving H2O2, formed in the oxidation of hemoglobin, and acid hematin acting as a pseudoperoxidase. We could find no evidence for other mechanisms of interference such as spectral error or azobilirubin destruction. Addition of potassium iodide, 4.0 mmol/L final concentration in the reaction mixture, eliminates interference from hemoglobin added to give concentrations as great as 10 g/L. It also eliminated the effects of hemolysis in the method of Ertingshausen et al. (Clin. Chem. 19: 1366, 1973), in which ethylene glycol is used as the accelerator.

IgA nephropathy associated with ankylosing spondylitis: occurrence in women as well as in men

Two patients (one male, one female) with ankylosing spondylitis (AS) and IgA nephropathy are described. The female patient is the first reported case to have AS and IgA nephropathy concurrently. Contrary to previously reported cases, her renal manifestation preceded her rheumatic symptoms. It is suggested that women with IgA nephropathy and AS may be overlooked as the severity of spondylitis and joint involvement is less than in men.

Synthesis and sulfatase inhibitory activities of (E)- and (Z)-4-hydroxytamoxifen sulfamates

We report the development of (E)- and (Z)-4-hydroxytamoxifen sulfamates as estrone sulfatase inhibitors, potential therapeutic agents for the treatment of breast cancer. Both compounds competitively inhibit estrone sulfatase isolated from rat liver with apparent Ki of 35.9 microM for (E)-4-hydroxytamoxifen sulfamate and an apparent Ki of > 500 microM for the (Z) isomer.

Effect of fluvastatin on lipoprotein profiles in treating renal transplant recipients with dyslipoproteinemia

A single, blinded placebo-drug trial was conducted to study the efficacy and safety of fluvastatin, a new 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor, in treating dyslipoproteinemia in 16 renal transplant recipients who had been on an immunosuppressive regimen that included cyclosporine (CsA). They were studied for 32 consecutive weeks, with 4 weeks of baseline treatment, 4 weeks of placebo, 12 weeks of treatment with fluvastatin 20 mg daily, and 12 weeks of fluvastatin 40 mg daily. Blood samples were obtained every 4 weeks for measurement of the lipoprotein profiles, which included total cholesterol (TC), triglyceride, low density lipoprotein (LDL)-, high density lipoprotein (HDL)-, HDL2-, HDL3- and very low density lipoprotein-cholesterol (C), apolipoprotein (Apo) A-1, Apo B, and lipoprotein(a). Fifteen patients completed the trial. After 12 weeks of treatment, fluvastatin 20 mg significantly reduced TC by 13.4% (from 6.7 +/- 0.5 [mean +/- SEM] to 5.8 +/- 0.2 mmol/L), LDL-C by 22% (from 4.1 +/- 0.3 to 3.2 +/- 0.2 mmol/L), and Apo B by 13.2% (from 159.6 +/- 8.8 to 138.6 +/- 9.2 mg/dl) (P < 0.005). The subsequent 12-week treatment of fluvastatin 40 mg significantly reduced TC by 16.4% to 5.6 +/- 0.3 mmol/L, LDL-C by 29.3% to 2.9 +/- 0.2 mmol/L, and Apo B by 18.2% to 130.6 +/- 5.5 mg/dl (P < 0.00005). There was no significant change in levels of other lipoproteins, including lipoprotein (a). There were no significant changes in the whole blood trough CsA concentrations, renal and liver function tests, and serum creatine phosphokinase level during treatment when compared with baseline and placebo. No patient complained of myalgia or failed to complete the study due to side effects of the drug. Fluvastatin appears to be safe and effective in treating dyslipoproteinemia in renal transplant recipients who are maintained on CsA.

Inhibition of human placental sterylsulfatase by synthetic analogs of estrone sulfate

Synthetic analogs of estrone sulfate which carry differently substituted sulfonyl groups at position 3 of an invariable 3-desoxyestrone (dE1) moiety were tested in vitro as inhibitors of the human placental sterylsulfatase. Using both placental microsomes and a highly purified placental sterylsulfatase preparation as the enzyme source and dehydroepiandrosterone [35S]sulfate or estrone [35S]sulfate as the substrate, the following order of inhibitory potencies was observed: dE1-3-sulfonylchloride > dE1-3-sulfonylfluoride approximately dE1-3-sulfonate > dE1-3-sulfonamide approximately 3-methylsulfonyl-dE1. According to the results, the association of enzyme and inhibitor appears to be favored by an electronegative substituent at the sulfur atom (-C1, -F, -O-). Since, however, even the most potent synthetic inhibitor was bound by the enzyme with significantly lower affinity than was the natural substrate estrone sulfate, an oxygen function between the aromatic ring and the sulfur atom may be necessary for high affinity binding towards the sterylsulfatase. In addition to its fast reversible association with the enzyme, dE1-3-sulfonylchloride further affected the sulfatase activity in a time-dependent manner. This latter inhibitory activity which may be due to a covalent modification (alkylation) of sterylsulfatase by the analog was partially prevented in the presence of substrate.

Hepatitis B virus-related nephropathy and lupus nephritis: morphologic similarities of two clinical entities

We compared the clinicopathologic features of 22 patients with hepatitis B virus-related membranous nephropathy, all with detectable glomerular hepatitis B e antigen, and of 26 patients with lupus nephritis class V. Both groups of patients similarly presented with heavy proteinuria or nephrotic syndrome; however, the patients with hepatitis B virus-related membranous nephropathy, who were predominantly male, did not have the extrarenal manifestations and autoantibodies seen in systemic lupus erythematosus. The glomerular lesions in both clinical entities were similar and at times indistinguishable, demonstrating polyclonal immunoglobulins and polytypic complements in similar subepithelial ultrastructural distribution. No morphologic feature, single or combined, carrying a high positive predictive value for the diagnosis of either nephritis was identified. Lesions such as hematoxyphil bodies and fingerprint dense deposits, distinctive of systemic lupus erythematosus, were rarely found. At the time of biopsy, when systemic lupus erythematosus is not clinically suspected, the diagnosis between hepatitis B virus-related membranous nephropathy and lupus nephritis may be difficult or impossible to differentiate, especially in geographic areas where both lupus nephritis and hepatitis B surface antigen carriers are common. This study focused on the use of specific monoclonal antisera to detect glomerular hepatitis B virus antigens, which contribute to the diagnosis of hepatitis B virus-related nephritis.

Primary glomerulonephritis with detectable glomerular hepatitis B virus antigens

The glomerular pathology and hepatitis B virus (HBV) antigens in renal biopsies were investigated in 100 consecutive patients with both primary glomerulonephritis and positive serology for hepatitis B surface antigen (HBsAg). Glomerular HBV antigens including HBsAg, hepatitis B core antigen (HBcAg), and hepatitis B e antigen (HBeAg) were examined in frozen tissue using both polyclonal and monoclonal antibodies. HBV serology and glomerular antigens were correlated. Using monoclonal antibodies, at least one of the three HBV antigens was detectable in glomeruli in 39% of the cases. These findings correspond mainly to detectable glomerular HBsAg and HBeAg in 22.3 and 28.4% of cases, respectively. A good correlation was found between glomerular and serum HBeAg but not observed for HBsAg. Serum HBcAg was not examined and not correlated with glomerular staining. When the diagnosis of HBV-related glomerulonephritis was based strictly on detectable glomerular antigens, three distinctive morphologies were identified: membranous nephropathy, mesangiocapillary glomerulonephritis, and mesangial proliferative glomerulonephritis with immunoglobulin A (IgA) deposits (IgA nephropathy). Each of these lesions may be seen in pure form or occasionally in overlapping form leading to double glomerulopathies. Glomerular HBeAg and HBsAg were associated with subepithelial and mesangial immune complexes, respectively. Rare overlap between membranous nephropathy and IgA nephropathy further emphasized the distinctive pathology of HBV-related glomerulonephritis and the independent etiological role of HBeAg and HBsAg. In other glomerulonephritis, which rarely demonstrated glomerular HBV antigens, the pathogenetic role of chronic HBV infection remains to be proven.

Posthysteroscopy fungal peritonitis in a patient on continuous ambulatory peritoneal dialysis

We report the first case of posthysteroscopy fungal peritonitis, which developed in a woman 11 days after she had a hysteroscopy for menorrhagia. A high vaginal swab grew Candida albicans and the same organism was cultured from the peritoneal dialysate effluent. A vaginoperitoneal communication was suspected to allow the distension medium to carry the fungus into the peritoneum. The potential use of a prophylactic local antifungal agent before hysteroscopy is discussed.

Protein C, protein S, and antithrombin III levels in patients on continuous ambulatory peritoneal dialysis and hemodialysis

Patients undergoing dialysis are subject to risk of thrombotic complications. We studied the plasma levels of natural coagulation inhibitors including protein C (PC), protein S (PS), and antithrombin III (AT III) in 20 patients on hemodialysis and 20 patients on continuous ambulatory peritoneal dialysis (CAPD). Total PS antigen, free PS antigen, immunological and functional activities of PC and AT III were measured. Hemodialysis patients had a higher total PS level but a lower free PS level compared with healthy controls. Both the immunological and functional activities of AT III in hemodialysis patients were significantly lower than those of controls. With the exception of total PS level, CAPD patients had comparable or even higher plasma level of natural coagulation inhibitors compared with healthy controls. Furthermore, the plasma levels of PC, PS, and AT III were significantly lower in hemodialysis patients compared with CAPD patients despite greater daily losses of PC, PS, and AT III through urinary and peritoneal routes in patients on CAPD treatment. Most of the AT III in the peritoneal dialysate was still functionally active but most of the PC was inactive. Our observations suggest an effective turnover and production of these natural coagulation inhibitors in patients on CAPD therapy but a similar compensatory mechanism does not operate efficiently in patients receiving hemodialysis.

Biochemical and pharmacological development of steroidal inhibitors of aromatase

Androstenedione analogs containing 7 alpha-substituents have proven to be potent inhibitors of aromatase both in vitro and in vivo. Several of these agents have exhibited higher affinity for the enzyme complex than the substrate. In order to examine further the interaction(s) of 7-substituted steroids with aromatase, biochemical and pharmacological studies were performed on 7 alpha-thiosubstituted androstenediones and 7-substituted 4,6-androstadiene-3,17-diones. Potent inhibition of aromatase activity in human placental microsomes has been observed with several new 7 alpha-thiosubstituted androstenediones. 7-Benzyl- and 7-phenethyl-4,6-androstadiene-3,17-diones effectively inhibited microsomal aromatase, with apparent Kis ranging from 61 to 174 nM. On the other hand, 7-phenyl-4,6-androstadiene-3,17-dione exhibited poor activity, with an apparent Ki of 1.42 microM. Similar inhibitory activity was observed with reconstituted, purified cytochrome P450Arom preparations. Additionally, these agents were evaluated for inhibition of aromatase activity in two human carcinoma cell lines, the MCF-7 human mammary cancer line and the JAr choriocarcinoma line. The 7 alpha-thiosubstituted androstenediones and 7-substituted 4,6-androstadiene-3,17-diones produced dose-dependent inhibitions of aromatase activity in the cell cultures. The most effective inhibitors were the 7 alpha-substituted androstenediones, with EC50 values ranging from 7.3 to 105 nM. Finally, the JAr cell culture system exhibited prolonged inhibition of aromatase activity following exposure to 7 alpha-APTADD, suggesting enzyme inactivation by this inhibitor. Thus, these agents are effective aromatase inhibitors, and the results encourage further development of this group of medicinal agents for the treatment of estrogen-dependent mammary carcinoma.

Comparison of non-breath-hold high resolution gadolinium-enhanced MRA with digital subtraction angiography in the evaluation on allograft renal artery stenosis

AIM

The study objective was to compare the diagnostic accuracy of non-breath-hold high resolution gadolinium-enhanced magnetic resonance angiography (Gd-MRA) with intra-arterial digital subtraction angiography (DSA) in the evaluation of allograft renal artery stenosis (ARAS).

MATERIALS AND METHODS

We studied 17 renal transplant recipients (six men, 11 women, age 34-64 years) with a systolic bruit in the transplant region beyond the early post-operative period. Gadolinium-enhanced magnetic resonance angiography was performed by non-breath-hold high resolution 3D acquisition in the oblique coronal plane using a 256 x 512 matrix.Digital subtraction angiography was performed with AP and oblique views and ARAS was graded as < or =50% or >50% diameter stenosis on the view that displayed the maximal narrowing.

RESULTS

Digital subtraction angiography showed >50% stenosis in seven patients, all of whom were diagnosed correctly on Gd-MRA. Gadolinium-enhanced magnetic resonance angiography diagnosed two patients with >50% stenosis which were not confirmed on DSA. Eight patients had no or < or =50% stenosis on both Gd-MRA and DSA. The sensitivity and specificity of Gd-MRA in revealing >50% stenosis were 100% and 75%, respectively, using DSA as the gold standard.

CONCLUSION

High resolution Gd-MRA employing a non-breath-hold technique is highly sensitive in the diagnosis of ARAS greater than 50%. It is preferred as a non-invasive screening technique to DSA in suspected ARAS.

Fluorescence polarization immunoassay for theophylline modified for use with dried blood spots on filter paper

We used dried blood spots successfully as alternative specimens for quantifying concentrations of theophylline in the circulation by a modified fluorescence polarization immunoassay (FPIA) with the Abbott TDx instrument. The method described is simple, rapid, and acceptably precise. More importantly, it can provide results comparable with those of the conventional serum assay. Results for 64 pairs of dried blood spots (y) and serum (x) specimens analyzed by the respective FPIA methods yielded the following regression parameters: y = 0.94x + 0.71, r = 0.988, and Sxy = 0.92. A major advantage of FPIA is that it requires only basic laboratory skills. When coupled with the use of dried blood spots, this system can be effective in remote theophylline monitoring, particularly suited for domiciliary care.

Memory enhancement mediated by the steroid sulfatase inhibitor (p-O-sulfamoyl)-N-tetradecanoyl tyramine

The intent of this study was to determine whether altering the metabolism of neurosteroids via blockade of the enzyme, steroid sulfatase, could enhance memory retention in rats. The steroid sulfatase inhibitor p-O-(sulfamoyl)-N-tetradecanoyl tyramine (DU-14) was administered alone and in combination with the neurosteroid dehydroepiandrosterone sulfate (DHEAS) to rats which were then tested for the reversal of scopolamine-induced amnesia. A single 30 mg/kg IP dose of DU-14 produced a significant inhibition of steroid sulfatase activity in both brain (14.8%), and liver (85.2%) tissues, 24 hours following administration. In a passive avoidance test, DU-14 enhanced the reversal of amnesia by DHEAS. These results suggest that steroid sulfatase inhibition can potentiate the memory enhancing properties of DHEAS.

Contribution of gene polymorphisms in the renin-angiotensin system to macroangiopathy in patients with diabetic nephropathy

The renin-angiotensin system is important in the control of hemodynamic status and pathogenesis of macrovascular disease, which is a major cause of morbidity and mortality in patients with type 2 diabetes with nephropathy. Serum angiotensin-converting enzyme (ACE) and angiotensinogen (Atg) levels are related to their respective gene polymorphisms. Seventy patients with type 2 diabetes with overt nephropathy (serum creatinine >/= 1.5 mg/dL) were studied. Serum ACE activity was measured by the spectrophotometric method. ACE deletion/insertion (D/I) and Atg M235T genotypes were determined by polymerase chain reaction. Patients with and without macroangiopathy were compared. Those with macroangiopathy had increased ACE activity (median, 60.9 U/L; range, 37.9 to 100 U/L versus without macroangiopathy, 47.9 U/L; range, 11.2 to 84.5 U/L; P = 0.01) and prevalence of ACE DD/DI genotypes (DD/DI:II: with macroangiopathy, 61%:39% versus without macroangiopathy, 34%:66%; P = 0.03). Multivariate analysis using age; sex; duration of diabetes; glycemic, blood pressure, and lipid level control; serum creatinine level; and presence of the ACE D allele showed that presence of the D allele (P = 0.03; odds ratio, 1.8; confidence interval, 1.1 to 3.1) and serum creatinine level (P = 0.0007) were independent risk factors for macroangiopathy. Association of the D allele became insignificant after serum ACE activity was included in the analysis in which only serum ACE activity (P = 0.004) and serum creatinine level (P = 0.01) were independent risk factors. Neither Atg M235T nor its synergistic effect with the ACE D allele showed an association with macroangiopathy. In conclusion, the ACE D allele is associated with macroangiopathy in Chinese patients with type 2 diabetes with nephropathy. The association is dependent on its effect on serum ACE activity, which is an independent risk factor for the development of macroangiopathy.

Replication of hepatitis B virus with corticosteroid therapy in hepatitis B virus related membranous nephropathy

The therapeutic effect of corticosteroid in hepatitis B virus (HBV) related membranous nephropathy was investigated in a 29-year-old chronic HBV carrier. Prednisolone (60 mg/day) was given for eight weeks and gradually reduced over the subsequent four months. In the renal biopsies taken before and after corticosteroid therapy, light microscopy revealed progression of sclerosis. Immunofluorescent staining showed glomerular capillary deposition of hepatitis B core antigen (HBcAg) by polyclonal antisera and hepatitis B e antigen (HBeAg) by monoclonal antibodies. Electron microscopy revealed 40-50 nm diameter virus-like particles in the glomeruli only from the biopsy performed after corticosteroid therapy. The serum concentrations of alanine aminotransferase, HBeAg, and HBV DNA increased with corticosteroid therapy suggesting active viral replication despite the absence of overt clinical hepatitis. Renal function did not improve and corticosteroid therapy was apparently not helpful in this patient. Our results conflict with the earlier notion that short-term corticosteroid does not interfere with a favorable outcome of the infection of the related renal disease.

Effective treatment of high-grade lymphoproliferative disorder after renal transplantation using autologous lymphocyte activated killer cell therapy

Posttransplantation lymphoproliferative disorders (PTLD) is not uncommon and can occur in 2% to 5% of solid organ recipients on immunosuppression. Epstein-Barr virus (EBV) infection or reactivation and intensive anti-T lymphocyte treatment are important pathogenetic factors for a large proportion of these disorders. Nonclonal lesions with polymorphous histology have a potential for regressing when the immunosuppressants are reduced or stopped. Clonal tumors with a monomorphous histology carry a poor prognosis, and the mortality rate for monoclonal lymphoma has been reported as high as 80%. We report a renal transplant recipient who developed high-grade monoclonal lymphoma only 4 months after a live-donor transplantation. The tumor was EBV positive. Reduction of immunosuppressants resulted in minimal regression of the tumor. The patient was treated with adoptive immunotherapy using ex vivo generation of autologous lymphocyte activated killer (LAK) cells. She had leukapheresis, and autologous peripheral blood mononuclear cells were obtained and cultured in interleukin-2 (IL-2)-rich medium for 9 to 10 days. The IL-2-activated LAK cells were reinfused into the patient without any systemic administration of IL-2. The patient experienced no side effects during the infusion. There was no rejection episode, and the renal function of the patient remained stable after treatment. Computed tomography scan performed 2 months after the infusion showed marked regression of the lesions in the liver and spleen. Five months later, magnetic resonance imaging showed complete resolution of the tumor lesions. Ultrasonography 13 months after the LAK cell infusion showed no lesion. The allograft function was not affected after treatment. Adoptive immunotherapy using IL-2-activated autologous LAK cells was effective in treating this renal transplant patient with EBV-positive high-grade lymphoma. The patient's kidney allograft functioned well without any rejection.

Dialysate hyaluronan concentration predicts survival but not peritoneal sclerosis in continuous ambulatory peritoneal dialysis

Hyaluronan is an important component of extracellular matrix and plays a critical role in early phases of wound healing. Peritoneal mesothelium is a major site of hyaluronan production. Serum hyaluronan concentration has been shown to predict survival in maintenance hemodialysis patients. We hypothesize that mesothelial production of hyaluronan during the stable phase of continuous ambulatory peritoneal dialysis (CAPD) predicts the risk of peritoneal adhesion and mortality. We studied peritoneal dialysate effluent (PDE) hyaluronan levels from 116 stable CAPD patients. They were then followed-up for 3 years. During the follow-up period, there were 196 episodes of peritonitis in 78 patients. Tenckhoff catheter was removed in 31 episodes (15.8%). Tenckhoff catheter was reinserted successfully in 12 cases, and CAPD was resumed. Peritoneal adhesion developed in 16 cases. Three patients died before Tenckhoff catheter reinsertion was attempted. There was no difference in stable-phase PDE hyaluronan levels between patients who developed peritoneal adhesion and those who did not (159 +/- 63 versus 227 +/- 194 microgram/L, P = 0.27). Thirty-three patients died during the study period. Patients who died had significantly higher PDE hyaluronan concentration than survivors (272 +/- 194 versus 170 +/- 105 microgram/L, P < 0.01). Univariate analysis showed that increased PDE hyaluronan level was associated with a shorter patient survival (P < 0.001). There was no association between PDE hyaluronan level and serum albumin, protein nitrogen appearance, and percentage of lean body mass. Multivariate analysis confirmed that PDE hyaluronan level, serum albumin, and diabetic state were independent predictors of survival. We conclude that PDE hyaluronan level during stable phase of CAPD does not predict the risk of postperitonitis adhesion. However, it is a strong independent predictor of survival in CAPD patients.

Chronic steroid sulfatase inhibition by (p-O-sulfamoyl)-N-tetradecanoyl tyramine increases dehydroepiandrosterone sulfate in whole brain

Dehydroepiandrosterone sulfate (DHEAS) is a neurosteroid which functions as a negative allosteric modulator of the GABA(A) receptor-gated chloride channel. Steroid sulfatase inhibitors including (p-O-sulfamoyl)-N-tetradecanoyl tyramine (DU-14), can potentiate the blockade of the amnestic effects of scopolamine by exogenously administered DHEAS. Moreover, when administered over a 15 day period, DU-14 can block scopolamine amnesia without the concurrent administration of DHEAS. Since the enzyme, steroid sulfatase, facilitates the hydrolysis of the sulfate moiety from DHEAS, the intent of this study was to determine whether chronic administration of DU-14 could increase whole brain concentrations of endogenous DHEAS. Rats were administered DU-14 or corn oil vehicle for 15 days. Following the last day the animals were sacrificed and the brains were removed and analyzed for DHEAS content. DU-14 increased the whole brain concentration of DHEAS 77.6%, from 0.65 +/- 0.06 to 1.15 +/- 0.12 microg/g (mean +/- SEM). This result suggests that steroid sulfatase inhibitors may enhance cognitive function following chronic treatment by increasing the concentration of excitatory neurosteroids such as DHEAS in the brain. Steroid sulfatase inhibitors, therefore, may provide a novel mechanism for facilitating central nervous system function.

Improved method for determining erythrocyte creatine by the diacetyl-alpha-naphthol reaction: elimination of endogenous glutathione interference

We describe a simple, accurate, and reproducible method for determining erythrocyte creatine. The method is free from glutathione inhibition and is adaptable to use with standard spectrophotometers as well as centrifugal analyzers. A clear filtrate, essentially free of protein, hemoglobin, and glutathione, is prepared from 0.1 mL of packed erythrocytes by treatment with Ba(OH)2 and ZnSO4, then reacted with diacetyl-alpha-naphthol. The standard curve for this method is linear from 10 to 500 mg/L. We show that endogenous sulfhydryl species such as erythrocyte glutathione will interfere with the creatine-diacetyl-alpha-naphthol reaction. This observation confirmed a suspicion of underestimation of erythrocyte creatine by the method of Griffiths (Clin. Chim. Acta 9: 210, 1964). Added p-chloromercuribenzoic acid did not completely eliminate this inhibition. In the present method these interfering sulfhydryl species are eliminated from the reaction mixture, thus obviating the need for p-chloromercuribenzoic acid and dialysis. The reference interval for this method is 42-80 mg/L.

Paecilomyces varioti peritonitis in patients on continuous ambulatory peritoneal dialysis

Paecilomyces varioti infection is a rare cause of peritonitis in patients on continuous ambulatory peritoneal dialysis (CAPD). We report two patients who developed P varioti peritonitis complicating CAPD. The clinical features and microbiological data of seven other previously reported cases are reviewed. Approximately half of the patients had received multiple antibiotics before the onset of the peritonitis because of either bacterial peritonitis or exit site infection. There was no particular pattern of peritoneal dialysate cell count, which was characteristic in this fungal peritonitis. Although all patients survived, morbidity was high. All patients required antifungal chemotherapy and removal of peritoneal catheter for eradication of the organism. Amphotericin B was effective in most cases. Patients of all previously reported cases did not go back to peritoneal dialysis after removal of peritoneal catheters. A combination of oral flucytosine and itraconazole was successful in treating our two patients. Although we managed to resume CAPD in our two patients with good functional outcome, abscesses and adhesions were major problems rendering most patients from other series failing to return to CAPD after recovery.

7-substituted 1,4,6-androstatriene-3,17-diones as enzyme-activated irreversible inhibitors of aromatase

7-Phenyl-1,4,6-androstatriene-3,17-dione (4), 7-benzyl-1,4,6-androstatriene-3,17-dione (5) and 7-phenethyl-1,4,6-androstatriene-3,17-dione (6) were synthesized and evaluated in vitro in human placental microsomes as enzyme-activated irreversible inhibitors of aromatase. The compounds were synthesized from appropriate 7-substituted 4,6-androstadiene-3,17-diones by reaction with DDQ under neutral conditions. All the compounds produced a first order inactivation of aromatase in the presence of NADPH but not in the absence of NADPH. Substrate 4-androstene-3,17-dione protected the enzyme from inactivation by the inhibitors. Furthermore, cysteine failed to protect aromatase from inactivation by compounds 5 and 6. In contrast, cysteine partially protected aromatase from inactivation by compound 4. Irreversibility studies illustrated the covalent nature of the inactivation by 4, 5 and 6. The above experimental evidence demonstrated that compounds 5 and 6 are effective enzyme-activated irreversible inhibitors of aromatase.

Measured-to-predicted creatinine generation ratio increases with time and decline in residual renal function in continuous ambulatory peritoneal dialysis

The expression of measured-to-predicted creatinine generation ratio (M/P) has been proposed as an index of compliance in continuous ambulatory peritoneal dialysis (CAPD) patients. Although M/P may not be sensitive enough for cross-sectional study, serial monitoring has been suggested to identify noncompliance. We attempted to evaluate serial changes of M/P from a nonselected group of CAPD patients. Sixty-three patients, all followed up for 2 years, were reviewed retrospectively. Their M/P ratios at years 0 and 2 were computed and compared. Baseline M/P had a normal distribution with a mean of 0.96 +/- 0.26. There was significant correlation between baseline M/P and residual glomerular filtration rate (GFR; r = -0.81; P < 0.0001). There were weak correlations between M/P and duration of dialysis (r = 0.52; P < 0.0001), body weight (r = -0.52; P < 0.0001), Kt/V (r = 0.31; P < 0.02), weekly creatinine clearance normalized to body surface area (r = 0.53; P < 0.0001), and serum albumin level (r = -0. 28; P < 0.05). After 2 years, M/P increased in 56 of 63 patients (88. 9%). Average M/P increased from 0.96 +/- 0.26 to 1.31 +/- 0.27 (P < 0.0001). Multivariant analysis showed M/P at year 0, which was largely determined by residual GFR, was the only independent factor affecting increase in M/P from year 0 to year 2. The general trend of increasing M/P was still present when only anuric patients were analyzed, although that was not statistically significant (1.21 +/- 0.14 to 1.32 +/- 0.24; P = 0.12). The finding of increasing M/P with time in CAPD patients, particularly those with significant residual renal function, suggests M/P may not be a reliable indicator of noncompliance, even for serial follow-up of the same patient. Better methods for assessment of compliance in CAPD patients are required.

Amphotericin B induced ocular toxicity in cryptococcal meningitis

We report a case of acute visual loss after a test dose (1 mg) of intravenous amphotericin B administered to a patient with systemic lupus erythematosus and with cryptococcal meningitis. Her visual acuity was normal prior to the injection of amphotericin B. The meningitis subsequently responded to miconazole and flucytosine treatment. Our findings suggest that amphotericin B should be withheld in the treatment of cryptococcal meningitis if disease of the optic nerve is strongly suspected.