Somatic PKD2 mutations in individual kidney and liver cysts support a "two-hit" model of cystogenesis in type 2 autosomal dominant polycystic kidney disease

An intriguing feature of autosomal dominant polycystic kidney disease (ADPKD) is the focal and sporadic formation of renal and extrarenal cysts. Recent documentation of somatic PKD1 mutations in cystic epithelia of patients with germ-line PKD1 mutations suggests a "two-hit" model for cystogenesis in type 1 ADPKD. This study tests whether the same mechanism for cystogenesis might also occur in type 2 ADPKD. Genomic DNA was obtained from 54 kidney and liver cysts from three patients with known germ-line PKD2 mutations, using procedures that minimize contamination of cells from noncystic tissue. Using intragenic and microsatellite markers, these cyst samples were screened for loss of heterozygosity. The same samples were also screened for somatic mutations in five of the 15 exons in PKD2 by single-stranded conformational polymorphism analysis. Loss of heterozygosity was found in five cysts, and unique intragenic mutations were found in seven other cysts. In 11 of these 12 cysts, it was also determined that the somatic mutation occurred nonrandomly in the copy of PKD2 inherited from the unaffected parent. These findings support the "two-hit" model as a unified mechanism for cystogenesis in ADPKD. In this model, the requirement of a somatic mutation as the rate-limiting step for individual cyst formation has potential therapeutic implications.

Coordinate expression of the autosomal dominant polycystic kidney disease proteins, polycystin-2 and polycystin-1, in normal and cystic tissue

A second gene for autosomal dominant polycystic kidney disease (ADPKD), PKD2, has been recently identified. Using antisera raised to the human PKD2 protein, polycystin-2, we describe for the first time its distribution in human fetal tissues, as well as its expression in adult kidney and polycystic PKD2 tissues. Its expression pattern is correlated with that of the PKD1 protein, polycystin-1. In normal kidney, expression of polycystin-2 strikingly parallels that of polycystin-1, with prominent expression by maturing proximal and distal tubules during development, but with a more pronounced distal pattern in adult life. In nonrenal tissues expression of both polycystin molecules is identical and especially notable in the developing epithelial structures of the pancreas, liver, lung, bowel, brain, reproductive organs, placenta, and thymus. Of interest, nonepithelial cell types such as vascular smooth muscle, skeletal muscle, myocardial cells, and neurons also express both proteins. In PKD2 cystic kidney and liver, we find polycystin-2 expression in the majority of cysts, although a significant minority are negative, a pattern mirrored by the PKD1 protein. The continued expression of polycystin-2 in PKD2 cysts is similar to that seen by polycystin-1 in PKD1 cysts, but contrasts with the reported absence of polycystin-2 expression in the renal cysts of Pkd2+/- mice. These results suggest that if a two-hit mechanism is required for cyst formation in PKD2 there is a high rate of somatic missense mutation. The coordinate presence or loss of both polycystin molecules in the same cysts supports previous experimental evidence that heterotypic interactions may stabilize these proteins.

[Isolation and identification of a saponine from Patrinia scabiosaefolia]

A saponine compound was isolated from the acetone extract of the roots and rhizomes of Patrinia scabiosaefolia Fish. ex Link. Its structure was identified by combination of chemical reaction and spectrum analysis as 3-O-alpha-L-rhamnopyranosyl-(1-2)-beta-D-xylopyranosyl oleanolic acid (giganteaside D), and part of its 13C-NMR data was revised by the 2D-NMR. The compound was found in the Patrinia for the first time.

[Influence of blood-activating drugs on adhesion and invasion of cells in lung cancer patients]

OBJECTIVE

To investigate the influence of some blood-activating drugs like Tetramethylpyrazine, Tanshinone II A, Hirudin and thrombin on adhesive and invasive behavior of PGCL3 and PAa cell lines.

METHODS

Using the above-mentioned blood-activating drugs in various concentration to treat PGCL3 and PAa cells, and the changes in adhesion to fibronectin and invasion in Boyden Chamber of these cells, alone or after interacted with human platelets, were observed.

RESULTS

Tetramethylpyrazine, Hirudin and thrombin could increase the adhesion of cells to fibronectin and Tanshinone II A decrease it. Tetramethylpyrazine, Tanshinone II A and Hirudin inhibited the invasion of PGCL3 cells in Boyden Chamber, and thrombin augmented the process.

CONCLUSION

The blood-activating drugs may either inhibit or promote the invasion and metastasis of PGCL3 and PAa cells in the light of various conditions.

LINE-1 elements at the sites of molecular rearrangements in Alport syndrome-diffuse leiomyomatosis

Deletions encompassing the 5' termini of the paired type IV collagen genes COL4A5 and COL4A6 on chromosome Xq22 give rise to Alport syndrome (AS) and associated diffuse leiomyomatosis (DL), a syndrome of disseminated smooth-muscle tumors involving the esophagus, large airways, and female reproductive tract. In this study, we report isolation and characterization of two deletion junctions. The first, in a patient described elsewhere, arose by a nonhomologous recombination event fusing a LINE-1 (L1) repetitive element in intron 1 of COL4A5 to intron 2 of COL4A6, resulting in a 13.4-kb deletion. The second, in a previously undescribed family, arose by unequal homologous recombination between the same L1 and a colinear L1 element in intron 2 of COL4A6, resulting in a>40-kb deletion. L1 elements have contributed to the emergence of this locus as a site of frequent recombinations by diverse mechanisms. These give rise to AS-DL by disruption of type IV collagen and perhaps other as yet unidentified genes, evidenced by deletions as small as 13.4 kb.

Yeast and viral RNA 5' triphosphatases comprise a new nucleoside triphosphatase family

Saccharomyces cerevisiae Cet1p catalyzes the first step of mRNA capping, the hydrolysis of the gamma phosphate of triphosphate-terminated RNA to form a 5' diphosphate end. The RNA triphosphatase activity of Cet1p is magnesium-dependent and has a turnover number of 1 s-1. Here we show that purified recombinant Cet1p possesses a robust ATPase activity (Km = 2.8 microM; Vmax = 25 s-1) in the presence of manganese. Cobalt is also an effective cofactor, but magnesium, calcium, copper, and zinc are not. Cet1p displays broad specificity in converting ribonucleoside triphosphates and deoxynucleoside triphosphates to their respective diphosphates. The manganese- and cobalt-dependent nucleoside triphosphatase of Cet1p resembles the nucleoside triphosphatase activities of the baculovirus LEF-4 and vaccinia virus D1 capping enzymes. Cet1p, LEF-4, and D1 share three collinear sequence motifs. Mutational analysis establishes that conserved glutamate and arginine side chains within these motifs are essential for the RNA triphosphatase and ATPase activities of Cet1p in vitro and for Cet1p function in vivo. These findings are in accord with the effects of single alanine mutations at analogous positions of vaccinia capping enzyme. We suggest that the metal-dependent RNA triphosphatases encoded by yeast and DNA viruses comprise a novel family of phosphohydrolase enzymes with a common active site.

[The chemical constituents of Epimedium koreanum Nakai]

Three new compounds were isolated from the aerial part of Epimedium koreanum Nakai. On the basis of spectroscopic and chemical evidences, they were elucidated as 3-O-beta-D-glucopyranosyl(1-->3)-alpha-L-(4-acetyl) rhamnopyranoside-anhydroicaritin-7-O-beta-D-glucopyranoside, 2-(p-hydroxyphenoxy)-5, 7-dihydroxy-6-prenylchromone, and 7-hydroxy-3, 4, 6-trimethoxy-9, 10-dihydrophenanthrene-2-O-beta-D-glucopyranoside.

Identification of PKDL, a novel polycystic kidney disease 2-like gene whose murine homologue is deleted in mice with kidney and retinal defects

Polycystin-1 and polycystin-2 are the products of PKD1 and PKD2, genes that are mutated in most cases of autosomal dominant polycystic kidney disease. Polycystin-2 shares approximately 46% homology with pore-forming domains of a number of cation channels. It has been suggested that polycystin-2 may function as a subunit of an ion channel whose activity is regulated by polycystin-1. Here we report the identification of a human gene, PKDL, which encodes a new member of the polycystin protein family designated polycystin-L. Polycystin-L has 50% amino acid sequence identity and 71% homology to polycystin-2 and has striking sequence and structural resemblance to the pore-forming alpha1 subunits of Ca2+ channels, suggesting that polycystin-L may function as a subunit of an ion channel. The full-length transcript of PKDL is expressed at high levels in fetal tissues, including kidney and liver, and down-regulated in adult tissues. PKDL was assigned to 10q24 by fluorescence in situ hybridization and is linked to D10S603 by radiation hybrid mapping. There is no evidence of linkage to PKDL in six ADPKD families that are unlinked to PKD1 or PKD2. The mouse homologue of PKDL is deleted in Krd mice, a deletion mutant with defects in the kidney and eye. We propose that PKDL is an excellent candidate for as yet unmapped cystic diseases in man and animals.

Patients treated by cardiologists have a lower in-hospital mortality for acute myocardial infarction

OBJECTIVES

We sought to determine the effect of specialty care on in-hospital mortality in patients with acute myocardial infarction.

BACKGROUND

There has been increasing pressure to limit access to specialists as a method to reduce the cost of health care. There is little known about the effect on outcome of this shift in the care of acutely ill patients.

METHODS

We analyzed the data from 30,715 direct hospital admissions for the treatment of acute myocardial infarction in Pennsylvania in 1993. A risk-adjusted in-hospital mortality model was developed in which 12 of 20 clinical variables were significant independent predictors of in-hospital mortality. To determine whether there were factors other than patient risk that significantly influenced in-hospital mortality, multiple logistic regression analysis was performed on physician, hospital and payer variables.

RESULTS

After adjustment for patient characteristics, a multiple logistic regression analysis identified treatment by a cardiologist (odds ratio=0.83 [confidence interval ¿CI¿=0.74 to 0.94] p < 0.003) and physicians treating a high volume of acute myocardial infarction patients (odds ratio=0.89 [CI=0.80 to 0.99] p < 0.03) as independent predictors of lower in-hospital mortality. Treatment by a cardiologist as compared to primary care physicians was also associated with a significantly lower length of stay for both medically treated patients (p < 0.01) and those undergoing revascularization (p < 0.01).

CONCLUSIONS

Treatment by a cardiologist is associated with approximately a 17% reduction in hospital mortality in acute myocardial infarction patients. In addition, patients of physicians treating a high volume of patients have approximately an 11% reduction in mortality. This has important implications for the optimal treatment of acute myocardial infarction in the current transformation of the health care delivery system.

A spectrum of mutations in the polycystic kidney disease-2 (PKD2) gene from eight Canadian kindreds

Autosomal dominant polycystic kidney disease (ADPKD) is a common Mendelian disorder that affects approximately 1 in 1000 live births. Linkage studies have shown that the majority (approximately 85%) of cases are due to mutations in PKD1 on chromosome 16p, while mutations in PKD2 on chromosome 4q account for most of the remaining cases. Locus heterogeneity in ADPKD is known to contribute to differences in disease severity, with PKD1-linked families having earlier onset of end-stage renal disease (ESRD) than PKD2-linked families (mean age at ESRD: 56 versus 70, respectively). In this study, 11 Canadian families with ADPKD were screened for PKD2 mutations. In four families, linkage to PKD2 was previously documented. In the remaining seven smaller families, one or more affected members had late-onset ESRD at age 70 or older. Using single-stranded conformational polymorphism analysis, one affected member from each family was screened for mutations in all 15 exons of PKD2, which were PCR-amplified from genomic templates. A spectrum of mutations was found in approximately 73% (8 of 11) of the families screened, with no difference in the detection rate between the PKD2-linked families and the families with late-onset ESRD. In three unrelated families, insertion or deletion of an adenosine in a polyadenosine tract (i.e., (A)8 at nt 2152-2159) was found on exon 11, suggesting that this mononucleotide repeat tract is prone to mutations from "slipped strand mispairing." All mutations, scattered between exons 1 and 11, are predicted to result in a truncated polycystin 2 that lacks both the calcium-binding EF-hand domain and the two cytoplasmic domains required for the interaction of polycystin 2 with polycystin 1 and with itself. Furthermore, no correlation was found between the location of the mutations in the PKD2 coding sequence and disease severity. Thus, these findings are consistent with other recently published reports and suggest that most PKD2 mutations are inactivating.

Antiinflammatory activity of the platelet-activating factor receptor antagonist A-85783

Accumulating evidence suggests an important role for the lipid mediator, platelet-activating factor (PAF), in cutaneous inflammation. In these studies the antiinflammatory effects of the potent and selective lipophilic PAF receptor antagonist A-85783 topically applied to the ventral ears of male Wistar rats were assessed. Intradermal injections of PAF into rat ears resulted in cutaneous inflammation as assessed by both ear thickness measurements and histological evaluation. Pretreatment of the ears with A-85783 resulted in an inhibition of subsequent PAF-induced inflammation. A-85783 treatment also inhibited phorbol myristic acetate-induced cutaneous inflammation, suggesting that the PAF receptor is involved in the etiology of this experimental dermatitis. These findings demonstrate that epicutaneous A-85783 is an appropriate tool to study the role of the PAF receptor in cutaneous inflammation, and suggest the possible clinical utility of this new class of antiinflammatory agents.

Activation of the epidermal platelet-activating factor receptor results in cytokine and cyclooxygenase-2 biosynthesis

Recent studies suggest that the lipid mediator platelet-activating factor (PAF) is involved in keratinocyte function and skin inflammation. Indeed, PAF is found in association with inflammatory skin diseases, intradermal injections of PAF induce inflammation, and keratinocytes express functional PAF receptors (PAF-R). One mechanism by which the keratinocyte PAF-R could contribute to epidermal functions and inflammatory states would be through the synthesis of inflammatory regulators, such as PAF, PGs, and cytokines. The ability of the epidermal PAF-R to induce the synthesis of these immunomodulators was tested using a model system created by transduction of the PAF-R-negative human epidermal cell line KB with the PAF-R. Activation of this epidermal PAF-R resulted in arachidonic acid release, and the biosynthesis of PAF and PGE2. In addition, the KB PAF-R triggered increased levels of mRNA and protein for the inducible isozyme of cyclooxygenase (COX-2) as well as IL-6 and IL-8, both of which have been implicated in skin inflammatory processes. Studies with the human keratinocyte-derived epidermal cell line HaCaT revealed that activation of the endogenous PAF-R led to the increased accumulation of COX-2, IL-6, and IL-8 mRNA similar to that seen with the KB PAF-R model system. Finally, treatment of HaCaT keratinocytes with IL-8 resulted in PAF biosynthesis, indicating the existence of a positive feedback loop between IL-8 and PAF in epidermal cells. These studies suggest involvement of PAF and the PAF-R in the epidermal cytokine network.

Identification and pharmacological characterization of platelet-activating factor and related 1-palmitoyl species in human inflammatory blistering diseases

Through its pro-inflammatory effects on leukocytes, endothelial cells, and keratinocytes, the lipid mediator platelet-activating factor (PAF) has been implicated in cutaneous inflammation. Although the 1-alkyl PAF species has been considered historically the most abundant and important ligand for the PAF receptor (PAF-R), other putative ligands for this receptor have been described including 1-acyl analogs of sn-2 acetyl glycerophosphocholines. Previous bioassays have demonstrated a PAF-like activity in lesions of the autoimmune blistering disease bullous pemphigoid. To assess the actual sn-2 acetyl glycerophosphocholine species that result in this PAF agonistic activity, we measured PAF and related sn-2 acetyl GPCs in fresh blister fluid samples from bullous pemphigoid and noninflammatory (suction-induced) bullae by mass spectrometry. We report the presence of 1-hexadecyl as well as the 1-acyl PAF analog 1-palmitoyl-2-acetyl glycerophosphocholine (PAPC) in inflammatory blister fluid samples. Because PAPC is the most abundant sn-2 acetyl glycerophosphocholine species found in all samples examined, the pharmacological effects of this species with respect to the PAF-R were determined using a model system created by transduction of a PAF-R-negative epidermoid cell line with the PAF-R. Radioligand binding and intracellular calcium mobilization studies indicated that PAPC is approximately 100x less potent than PAF. Though a weak agonist, PAPC could induce PAF biosynthesis and PAF-R desensitization. Finally, intradermal injections of PAF and PAPC into the ventral ears of rats demonstrated that PAPC was 100x less potent in vivo. These studies suggest possible involvement of PAF and related species in inflammatory bullous diseases.

Absence of association between Alzheimer disease and the -491 regulatory region polymorphism of APOE

A novel polymorphism (-491 A/T) within the regulatory region on the apolipoprotein E gene has recently been reported to be associated with risk for Alzheimer disease (AD). To test this association in an independent data set, we have examined this polymorphism in a sample of 88 well-characterized AD cases and compared the allele frequency and genotype frequencies for this polymorphism with those observed in 112 cognitively normal subjects drawn from the same ethnic group. These results suggest that in the current data set at least, the -491 A/T polymorphism is not associated with risk for AD, but may be in partial linkage disequilibrium with the APOE epsilon2/epsilon3/epsilon4 polymorphism.

[A case of report--interferon therapy is useful for chronic hepatitis C with human immunodeficiency virus infection]

A 42-year-old male type A hemophiliae who been using coagulates since 1971 was diagnosed Human Immunodeficiency Virus (HIV) positive in 1993. Medical history included liver disfunction in 1987, with chronic hepatitis C (CHC) diagnosed in 1989. He was admitted to the hospital in October, 1994 because of general fatigue. Serum transaminase was elevated, CD4 was 221/micro L, and CD8 was 990. CD4/CD8 ratio was 0.2. HCV was of genotype 2b and 10(6) copies/50 microL, 8 week-Interferon (IFN)-beta treatment was started. HCV RNA was eliminated by week 8 and was sustained for one year with no severe side effects. With careful patient screening, IFN therapy for CHC with HIV may be an effective treatment.

[Clinical observation on the adhesion molecule expression and functional study of platelets in cancer patients]

OBJECTIVE

To investigate adhesion molecule expression and functional status of platelets in cancer patients and their relation to cancer progression.

METHODS

Using flow cytometry to measure the expression of surface antigens and functional status of platelets in 50 healthy donors and 181 cancer patients.

RESULTS

Comparing with normal donors, the expression of CD42a in cancer patients decreased, and that of TSP and CD36 increased. The number of platelets with CD36+ TSP+, CD36+ TSP-, CD9+, CD31+, CD62+ CD63-, CD62+ CD63+, CD62- CD63+ phenotypes also increased. There was significant difference between patients in early stage and those in advanced stage, but there was no significant difference between the patients in early stage and healthy donors. The expression of CD41 did not change in cancer patients.

CONCLUSION

In cancer patients, especially in the advanced stage of the disease, the expression of the adhesion molecules on platelets and their released products increase, indicative of an activated state of the platelets.

A novel frameshift mutation induced by an adenosine insertion in the polycystic kidney disease 2 (PKD2) gene

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common Mendelian disorders and is genetically heterogeneous. Linkage studies have shown that the majority (approximately 85%) of ADPKD cases are due to mutations in PKD1 on chromosome 16p13.3, while mutations in PKD2 on chromosome 4q21-q23 are thought to account for most of the remaining cases. In this report, we describe the mutation in a large four-generation ADPKD family (TOR-PKD77) which we had mapped to the PKD2 locus by linkage analysis. In this family, we screened for mutations by directly sequencing two nested RT-PCR fragments (PKD2N1 and PKD2N2) that cover approximately 90% of the PKD2 open reading frame. In the affected members, we identified a novel single adenosine insertion (2160InsA) in the PKD2N2 fragment. This mutation occurred in the polyadenosine tract (nt2152-2159) of exon 11 and is predicted to result in a frameshift with premature translation termination of the PKD2 product, polycystin 22, immediately after codon 723. The truncated polycystin 2 is predicted to lack the calcium-binding EF-hand domain and two cytoplasmic domains required for the homodimerization of polycystin 2 with itself and for the heterodimerization of polycystin 2 with polycystin 1.

BMP-2 and OP-1 exert direct and opposite effects on renal branching morphogenesis

The bone morphogenetic proteins, BMP-2 and OP-1, are candidates for growth factors that control renal branching morphogenesis. We examined their effects in embryonic kidney explants and in the mIMCD-3 cell model of collecting duct morphogenesis (mIMCD-3 cells are derived from the terminal inner medullary collecting duct of the SV40 mouse). Osteogenic protein-1 (OP-1), at a dose of 0.25 nM, increased explant growth by 30% (P = 0.001). In contrast, 100-fold greater concentrations of OP-1 (28 nM) decreased explant growth by 10% (P < 0.001). BMP-2 was entirely inhibitory (maximum inhibition of 7% at 5 nM, P < 0.0004). In an in vitro model for branching morphogenesis utilizing the kidney epithelial cell line, mIMCD-3, low doses of OP-1 (< 0.5 nM) increased the number of tubular structures formed by 28 +/- 5% (P = 0.01), whereas concentrations > 0.5 nM decreased that number by 22 +/- 8% (P = 0.02). All concentrations of BMP-2 (0.05-10 nM) were inhibitory (maximum inhibition at 10 nM of 88 +/- 3%, P < 0.0001). Stimulatory doses of OP-1 increased tubular length (P = 0.003) and the number of branch points/structure (3.2-fold increase, P = 0.0005) compared with BMP-2. To determine the molecular basis for these effects, we demonstrated that BMP-2 is bound to mIMCD-3 cells by the type I serine/threonine kinase receptor, ALK-3, and that OP-1 bound to an approximately 80-kDa protein using ligand-receptor affinity assays. To demonstrate that OP-1 can exert both stimulatory and inhibitory effects within a developing kidney, embryonic explants were treated with agarose beads saturated with 2 microM OP-1. OP-1 decreased the number of ureteric bud/collecting duct branches adjacent to the beads by 58 +/- 1% (P < 0.0001). In contrast, the number of branches in tissue distal to the OP-1 beads was enhanced, suggesting a stimulatory effect at lower doses of OP-1. We conclude that OP-1 and BMP-2 directly control branching morphogenesis and that the effects of OP-1 are dependent on its local concentration within developing kidney tissue.

[Effect of beta-carotene on 60Co-gamma-induced mutation at T-lymphocyte hypoxanthine-guanine phosphoribosyl transferase locus in rats]

AIM

To study the effect of beta-carotene (beta-Car) on radiation-induced mutation.

METHODS

Mutant frequency at T-lymphocyte hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus in rats was measured using a T-lymphocyte cloning technique and malondialdehyde (MDA) was measured using a thiobarbituric acid (TBA).

RESULTS

Mutant frequency at the HGPRT locus was elevated by 60Co-gamma 3.75 Gy, and was reduced by ig beta-car 20 and 10 mg.kg-1 (P < 0.05), but not by beta-Car 5 mg.kg-1. It showed a dose-dependent relationship. MDA was signifcantly reduced in plasma of rats given beta-Car after 60 Co-gamma radiation. There was positive coherence between MDA and mutant frequency at the HGPRT locus (r = 0.9978, P < 0.05).

CONCLUSIONS

Radiation-induced mutation is inhibited by beta-Car, associated with antioxidant action of beta-Car.

Association of angiotensinogen gene T235 variant with progression of immunoglobin A nephropathy in Caucasian patients

Genetic variability in the renin-angiotensin system may modify renal responses to injury and disease progression. We examined whether the M235T polymorphism of the angiotensinogen (AGT) gene, the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) gene, and the A1166--> C polymorphism of the angiotensin II type 1 receptor gene may be associated with disease progression in 168 Caucasian patients with IgA nephropathy. All patients had serial measurements of their creatinine clearance, proteinuria, and blood pressure (mean+/-SD) with a follow-up of 6.1+/-4.7 yr. The genotype frequencies for each gene were consistent with Hardy-Weinberg equilibrium, and were similar to those of 100 Caucasian control subjects. We examined two primary outcomes: (a) the rate of deterioration of Ccr, and (b) the maximal level of proteinuria. We found that patients with the AGT MT (n = 79) and TT (n = 29) genotypes had a faster rate of deterioration of Ccr than those with the MM (n = 60) genotype (i.e., median values, -6.6 and -6.2 vs. -3. 0 ml/min/yr, respectively; P = 0.01 by Kruskal-Wallis test). Similarly, patients with AGT MT and TT genotypes had higher maximal values of proteinuria than those with the MM genotype (i.e., median values, 2.5 and 3.5 vs. 2.0 g/d, respectively; P < 0.02 by Kruskal-Wallis test). Neither the ACE insertion/deletion nor angiotensin II type I A1166--> C gene polymorphism was associated with disease progression or proteinuria in univariate analysis. Multivariant analysis, however, detected an interaction between the AGT and ACE gene polymorphisms with the presence of ACE/DD polymorphism adversely affecting disease progression only in patients with the AGT/MM genotype (P = 0.008). Neither of these gene polymorphisms was associated with systemic hypertension. Our results suggest that polymorphisms at the AGT and ACE gene loci are important markers for predicting progression to chronic renal failure in Caucasian patients with IgA nephropathy.

[Selection of TLC solvent system for separating substituted ferrocyclopentadienyl borane using orthogonal array method]

A series of substituted ferro-cyclopentadienyl borane compounds were separated by using thin-layer chromatographic technique. The optimum mobile phase was acetone-cyclohexane-tetraethyl ammonium halide (0.59:8.24:1.18). The orthogonal array method was used to get the optimum chromatographic condition. The types and the concentrations of different kinds of ion-pair reagents, the contents of acetone and cyclohexane were considered as factors which affected the results of separation. The operating conditions for each experiment was adopted based on the L9 (3(4)) design. A statistical method of variance analysis was used to evaluate the overall degree of separation (D(S)), a criterion which reflects the degree of optimization. As a result, we found the most important factors that affected the separation and the optimum chromatographic condition for 8 compounds of this sort.

A randomized controlled trial of verapamil on cyclosporine nephrotoxicity in heart and lung transplant recipients

BACKGROUND

Cyclosporine (CsA) is a potent immunosuppressive drug widely used in organ transplantation and in the treatment of autoimmune diseases (1, 2). However, its common nephrotoxic effect is a major limiting factor. Short-term CsA treatment has been shown to cause reversible renal vasoconstriction, whereas long-term treatment can lead to an afferent arteriolopathy and chronic renal failure.

METHODS

We performed a randomized controlled trial to examine the short-term renal effects of verapamil in 32 CsA-treated heart or lung transplant recipients. Sixteen patients each were randomized to receive a 6-week course of verapamil or control treatment (atenolol in hypertensive patients and placebo in normotensive patients) 1-2 months after transplantation. An 8-hr sequential clearance study of inulin and p-aminohippuric acid for estimating glomerular filtration rate and renal plasma flow, respectively, was performed at baseline and at completion of study. The integral area under the curve of the clearance parameter over 8 hr was then calculated to generate a clearance-time index.

RESULTS

There was no difference in the clearance-time indices for inulin and p-aminohippuric acid between the two groups at baseline. However, at the completion of study, the within-group change in the glomerular filtration rate clearance-time index was different between the verapamil and control groups (48+/-20 vs. -35+/-17 ml/min/1.73 m2 x hr, respectively; P=0.0038). A similar trend was seen for renal plasma flow, but did not reach statistical significance. Mean arterial blood pressure and whole-blood CsA levels did not differ between the two groups during the study. Verapamil treatment was also associated with a decrease in CsA dose requirement (7.6+/-0.58 mg/kg/day at baseline vs. 4.6+/-0.40 mg/kg/day at completion; P<0.001) without any significant change in trough whole blood CsA levels. Rejection episodes did not differ between the two groups.

CONCLUSIONS

The use of verapamil in the heart or lung transplant recipients may therefore provide both renal protective effects and cost savings.

[Active constituents reducing side-effects of prednisone acetate in leaves of Panax ginseng C.A.Mey]

The rise of total lipid, triglyceride and total cholesterol, and the drop of cortisol in serum induced by PA can be significantly inhibited by total ginsenosides in the leaves of Panax ginseng [GSL, 60 mg/(kg.d)]. From GSL ten compounds have been isolated and identified as ginsenoside-Rb2, -Rc, -Rd, -Re, -Rg1 -F3, F2, -Rg2, 20(R)-Rg2 and -Rh1, respectively. Pharmacological study has proved ginsenoside-Re to be the chief active constituent of GSL.

Validation of a predictive model of idiopathic membranous nephropathy: its clinical and research implications

Although a number of factors have consistently correlated with progression to chronic renal insufficiency (CRI) in idiopathic membranous glomerulonephropathy (IMGN), they appear late, are not quantitative in nature and have not been validated. We have determined that the highest sustained six-month period of proteinuria is an important predictor of progression. Using multiple logistic modelling, the only additional prognostic variables of importance in 184 Canadian patients were the initial creatinine clearance and the rate of change in function over this six-month interval. Independent data from Italy (101 patients) and Finland (78 patients) were obtained for comparison. Sensitivity, specificity, negative and positive predictive values and overall accuracy, as well as Pearson's goodness-of-fit and Harrell's "C" statistic were used to assess the fits of the model. Accuracy of prediction was > or = 85% in all three countries. Pearson's Chi-square goodness-of-fit showed good agreement across the spectrum and Harrell's "C" statistic was > or = 90%. Therefore, a predictive, semiquantitative algorithm in IMGN has been validated. Its relevance in patient management and in clinical trials is illustrated.

Frequency-domain optical imaging of absorption and scattering distributions by a Born iterative method

We presents a Born; iterative method, for reconstructing optical properties of turbid media by means of frequency-domain data. The approach is based on iterative solution of a linear perturbation equation, which is derived from the integral from of the Helmholtz wave equation for photon-density waves in each iteration the total field and the associated weight matrix are recalculated based on the previous reconstructed image. We then obtain a new estimate by solving the updated perturbation equation. The forward solution, also based on a Helmholtz equation, is obtained by a multigrid finite difference method. The inversion is carried out through a Tikhonov regularized optimization process by the conjugate gradient descent method. Using this method, we first reconstruct the distribution of the complex wave numbers in a test medium, from which the absorption and the scattering distributions are then derived. Simulation results with two-dimensional test media have shown that this method can yield quantitatively (in terms of coefficient valued) as well as qualitatively (in terms of object location and shape) accurate reconstructions of absorption and scattering distributions in cases in which the first-order Born approximation cannot work well. Both full-angle and limited-angle measurement schemes have been simulated to examine the effect of the location of detectors and sources. The robustness of the algorithm to noise has also been evaluated.

[Minor saponins from leaves of Panax ginseng C.A. Meyer]

Five compounds were isolated from the leaves of Panax ginseng and characterized as 20(R)-protopanaxatriol, daucosterine, ginsenoside-F2, ginsenoside-F3 and majoroside-F4 on the basis of spectral analysis and chemical evidence. Among them, majoroside-F4 is obtained from plant for the first time.

The pharmacology of the novel and selective sigma ligand, PD 144418

The pharmacology of PD 144418 (1-propyl-5-(3-p-tolyl-isoxazol-5-yl)-1,2,3,6-tetrahydropyridine) was characterized using neurochemical, biochemical and behavioral techniques. For sigma (sigma 1 and sigma 2 respectively) sites, PD 144418 affinities were determined using whole guinea pig brain membranes with [3H](+)-pentazocine and neuroblastoma x glioma cell membranes using [3H]1,3,di-O-tolylguanidine (DTG) in the presence of 200 nM (+)-pentazocine. PD 144418 exhibited an affinity for sigma 1 of 0.08 nM (Ki) versus a K1 of 1377 nM for sigma 2 site. Additional receptor binding studies indicated that PD 144418 lacked affinity for dopaminergic, adrenergic, muscarinic and a variety of other receptors. In vitro studies indicated that PD 144418 reversed the N-methyl-D-aspartate (NMDA)-induced increase in cyclic GMP (cGMP) in rat cerebellar slices without affecting the basal levels, suggesting that sigma 1 sites may be important in the regulation of glutamine-induced actions. PD 144418 potentiated the decrease in 5-hydroxytryptophan caused by haloperidol in the mesolimbic region, but by itself had no effect in 5-hydroxytrypamine (5-HT) and dopamine (DA) synthesis. Behaviorally, similar to other sigma ligands, PD 144418 antagonized mescaline-induced scratching at doses that did not alter spontaneous motor activity. This action is suggestive of potential antipsychotic property. It exhibited no anxiolytic and antidepressant properties in the models used. These results show that PD 144418 is a very selective sigma 1 agent, devoid of any significant affinity for other receptors and that sigma 1 site may modulate actions in the CNS.

Identification and localization of polycystin, the PKD1 gene product

Polycystin, the product of autosomal dominant polycystic kidney disease (ADPKD) 1 gene (PKD1) is the cardinal member of a novel class of proteins. As a first step towards elucidating the function of polycystin and the pathogenesis of ADPKD, three types of information were collected in the current study: the subcellular localization of polycystin, the spatial and temporal distribution of the protein within normal tissues and the effects of ADPKD mutations on the pattern of expression in affected tissues. Antisera directed against a synthetic peptide and two recombinant proteins of different domains of polycystin revealed the presence of an approximately 400-kD protein (polycystin) in the membrane fractions of normal fetal, adult, and ADPKD kidneys. Immunohistological studies localized polycystin to renal tubular epithelia, hepatic bile ductules, and pancreatic ducts, all sites of cystic changes in ADPKD, as well as in tissues such as skin that are not known to be affected in ADPKD. By electron microscopy, polycystin was predominantly associated with plasma membranes. Polycystin was significantly less abundant in adult than in fetal epithelia. In contrast, polycystin was overexpressed in most, but not all, cysts in ADPKD kidneys.

[Effects of ginsenosides from stems and leaves on hyperlipemia induced by prednisone acetate in rabbits]

Rise of total lipid, total cholesterol and triglyceride in rabbits were markedly inhibited by oral administration of ginsenosides from stems and leaves at a daily dose of 60mg/kg. The inhibitory rates were 66.2%, 92.8% and 58.1% respectively.

[Efficiency of combination chemotherapy and interferon-alpha therapy in a patient with AIDS-related cutaneous and gastrointestinal Kaposi's sarcoma]

A 40-year-old male was admitted to the hospital with acquired immunodeficiency syndrome (AIDS) and Pneumocystis carinii pneumonia (PCP). Two months before admission the patient had a high fever, general fatigue and mild epigastic tenderness. On admission, physical examination revealed numerous small tumors on the head, gingiva, neck, nasal ala, anterior forehead, anterior thoracic, bilateral sole and bilateral lower limbs. At that time, the CD4 cell count was 130/microliters. Upper GI endoscopy was performed because of sever epigastralgia and hematemesis. The gastric mucosa was diffusely nodular and erythematous with bleeding. This biopsy showed Kaposi's sarcoma, and the same findings were obtained from the duodenum, rectum and skin, AIDS with related cutaneous and gastrointestinal KS and PCP was diagnosed. We performed a combination of chemotherapy and Interferon-alpha therapy, and the KS almost completely disappeared within 3 months.

High-level expression of active human plasminogen activator inhibitor type 1 (PAI-1) in E. coli

Plasminogen activator inhibitor 1 (PAI-1) is an important regulator of plasminogen activation, which inhibits both tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). The DNA sequence encoding mature PAI-1 protein was inserted into an inducible expression vector. This gene was highly expressed to produce a soluble active protein in E. coli cells. The amount of the recombinant protein was up to 20% of total cellular protein. By efficient purification with a yield of about 15-20%, the recombinant protein could be purified to homogeneity with its specific activity up to 6.1 x 10(4) (uPA) IU/mg. Its inhibitory activity declined during incubation at 37 degrees C with a half life of about 2 hr.

Ginsenoside-Ia: a novel minor saponin from the leaves of Panax ginseng

A new saponin, named ginsenoside-I (a), was isolated from leaves of Panax Ginseng, together with nine known saponins, and its structure was elucidated as 3beta,6alpha,12beta,20(S)-tetrahydroxyldammar-24(25)-ene (20- O-beta-D-glucopyranosyl)-3-O-beta-D-glucopyranoside on the basis of chemical and 2D-NMR methods.

Solid phase organic synthesis (SPOS): a novel route to diketopiperazines and diketomorpholines

The solid phase synthesis of libraries containing a 1,3,4,6-tetrasubstituted-2,5-diketo-1,4-piperazine scaffold (DKP) or a 3,4,6-trisubstituted-2,5-diketo-1,4-morpholine scaffold (DKM) from alpha-bromocarboxylic acids and amines is described. Using a design strategy which we refer to as divergent library design, both templates were prepared from a common intermediate. The general utility of this synthetic route in creating novel, non-peptidyl chemical libraries is discussed.

The aplastic form of renal osteodystrophy

That bone disease accompanies renal failure has been known for over 100 years. This bone disease (renal osteodystrophy) has been variously attributed to hyperparathyroidism, vitamin D deficiency, aluminium toxicity, iron toxicity, uraemia, and a host of other aetiologies. In addition, the form the bone disease takes has been variously described as osteitis fibrosa, osteomalacia, mixed uraemic osteodystrophy and the aplastic (adynamic) lesion. In this manuscript we will focus on the aetiology, consequences, diagnosis and possible management of the aplastic form of the disease. The renal osteodystrophy study was a prospective, cross-sectional study of renal bone disease in a largely unselected population of patients receiving dialysis in three hospitals in Toronto. A variety of non-invasive data (parathyroid hormone (PTH), aluminium, etc.) and bone histology were obtained and analysed to assess pathogenesis, diagnostic criteria and management. We have defined the aplastic lesion as having low bone formation without a marked increase in unmineralized osteoid (i.e. excluding osteomalacia). We have noted that it may be associated with increased aluminium or little to no aluminium. With increased aluminium the patients have a poorer prognosis both with regards to bone disease and mortality, and they should be managed appropriately to alleviate aluminium toxicity. With lesser amounts of aluminium, morbidity and mortality are less severely impacted, but not normal. We have shown that the low bone formation, of the aplastic lesion without aluminium may be "normalized' by increasing PTH levels. It is concluded that aplastic bone disease carries adverse consequences both in terms of bone problems and survival. In the absence of aluminium toxicity the stimulation of PTH effectively corrects the bone formation abnormality. Whether this will alleviate the adverse consequences will be difficult to study. Avoiding the problem by not over-suppressing PTH seems a reasonable approach at this point.

Determination of the in vivo post-antibiotic effects of ciprofloxacin and rifampicin

A modified rabbit meningitis model is described for determining the PAE in vivo, which utilised a self-standing device for repeatedly sampling pure CSF. The model allowed the PAEs of ciprofloxacin and rifampicin on Escherichia coli ATCC 25922 to be determined following PAE induction in vitro, or in vivo in CSF after intrathecal injection or during the last 1.5 h of a 7 h iv continuous infusion. The estimated volumes of distribution of ciprofloxacin and rifampicin in CSF were 0.68 +/- 0.24 mL and 0.74 +/- 0.04 mL, respectively, and the terminal elimination half lives were 1.8 +/- 0.5 h and 2.2 +/- 0.3 h, respectively. PAEs of approximately 2 h were obtained in vivo and in vitro after exposing E. coli to 3 x MIC of ciprofloxacin in vitro and to 1 x MIC of drug in vivo. When the organism was exposed to rapidly declining concentrations in vivo, only a minimal PAE was observed for both antibiotics. Moreover, a PAE of 3.1 +/- 1.3 h of rifampicin was obtained in vivo, being smaller than the 4.8 h PAE observed in vitro, which might be explained by the binding of 45 +/- 6.5% rifampicin to proteins in the CSF.

Relationship between intact 1-84 parathyroid hormone and bone histomorphometric parameters in dialysis patients without aluminum toxicity

With the markedly reduced usage of aluminum salts in renal failure, parathyroid hormone (PTH) has become the major determinant of currently seen bone disease. Clinicians now must consider what PTH level should be sought. Too low a level may lead to the aplastic bone lesion (low turnover bone), and too high a level may cause osteitis fibrosa. Furthermore, conventional normal PTH levels may not be a suitable target because of the well-known resistance to PTH in uremic patients. In this report, we derive the PTH levels that best distinguish patients with low and high bone formation states from those with normal bone formation in a group of 175 dialysis patients without aluminum toxicity. Using bone histological parameters, we propose that ideally PTH levels should be maintained between 10 pmol/L (100 pg/mL) and 20 to 30 pmol/L (200 to 300 pg/mL) in chronic dialysis patients, levels two to four times the upper limit of values found in normal subjects.

[A clinical trial of lansoprazole in the treatment of duodenal ulcer]

To evaluate the efficacy of a second generation acid pump inhibitor-lansoprazole (L) a controlled clinical trial in 72 patients of duodenal ulcer was carried out with omeprazole (O) as control. The results showed that the ulcer healing rate after 4-week treatment was 97.4% in lansoprazole group and 91.2% in omeprazole, while the effective rate was 100% and 97.1% respectively (P > 0.05). Ulcer related pain was relieved more quickly in lansoprazole group. The pain relief rate after treatment of 3 days was different significantly between the two group, being 74.3% (L) and 51.6% (O) respectively (P < 0.05). No marked side-effect was observed in lansoprazole group. It is shown that lansoprazole is effective and safe for treatment of duodenal ulcer.

An analysis of predictors of long-term cadaveric renal allograft survival

To determine factors predictive of long-term graft function in patients treated prophylactically with an antilymphocyte antibody, 670 first cadaveric adult renal transplant procedures performed between 1985 and 1991 were reviewed. The actuarial 1- and 5-year patient survival in this group was 95% and 87% respectively, and graft survival was 84% and 70% respectively. The final analysis was based on a study group of 635 patients which excluded 28 patients who lost grafts to early technical failures and 8 patients who were not induced with an antilymphocyte preparation. Multivariate analysis showed that 5-year graft survival was lower in patients with delayed graft function (p = 0.0001), in those who had an acute rejection episode in the first 6 months post-transplant (p = 0.0001), recipients greater than 55 years of age at the time of transplant (p = 0.0001), in patients who were highly sensitized at the time of transplant (p = 0.0331) and, finally, in those who received a graft from an older donor (p = 0.044). The 209 patients with delayed graft function had a 16% lower long-term graft survival than 425 patients with early graft function (62% vs. 78% respectively at 5 years). One or more rejection episodes in the first 6 months post-transplant (329 patients) reduced long-term graft survival by 13% compared to those who did not have a rejection episode (67% vs. 80% respectively at 5 years).(ABSTRACT TRUNCATED AT 250 WORDS)

Phase I-II study of vinblastine and oral cyclosporin A in metastatic renal cell carcinoma

A phase I-II clinical trial was conducted to determine the maximum-tolerated dose (MTD) of oral cyclosporine (CsA) and vinblastine in patients with metastatic renal cell cancer (RCC) as well as to estimate the response rate. Sixteen patients received a 5 mg/kg oral loading dose of CsA followed by 3 days of CsA in 4 divided daily doses escalating from 10 mg/kg per day up to 17 mg/kg per day. Vinblastine (Vbl) was administered as an intravenous bolus on the morning of the 3rd day with dose escalation from 6 to 10 mg/m2. Cycles were repeated every 4 weeks until tumor progression. Forty-nine cycles of CsA with vinblastine were administered. The maximum tolerated dose of Vbl was 10 mg/m2, with neutropenia as the dose-limiting toxicity resulting in one death. CsA could not be escalated above 17 mg/kg per day because of nausea and vomiting. Other toxicities included constipation (100%), malaise (100%), temporary increase in pain (36%), and one seizure that may have been drug-related. There were no clinically significant changes in renal function or serum bilirubin. Mean peak whole-blood CsA level at the highest CsA dose level was 919 ng/ml (range: 414-1,827) with a trough prior to Vbl injection of 451 ng/ml (range: 128-1,229). There were no tumor responses. The combination of oral CsA and Vbl is not nephrotoxic but is poorly tolerated. In most patients optimal blood levels of CsA for reversal of MDR cannot be reliably achieved, and vinblastine dose intensity must be compromised because of the significant toxicity of this regimen.

Expression of human plasminogen activator inhibitor-2 in the baculovirus expression system

A cDNA coding for human plasminogen activator inhibitor-2 (PAI-2) was transferred into the genome of Autographa californica nuclear polyhedrosis virus adjacent to the polyhedrin promoter. Cells infected with recombinant virus synthesized a 43-kDa PAI-2 protein, the majority of which was secreted. The recombinant PAI-2 was identical to native PAI-2 purified from human placenta with respect to interaction with polyclonal antibody and inhibition of urokinase-type plasminogen activator.

Sustained vasoconstriction associated with daily cyclosporine dose in heart and lung transplant recipients: potential pathophysiologic role of endothelin

Transient decreases in glomerular filtration rate (GFR) and renal plasma flow (RPF) have been associated with each daily dose of cyclosporine (CYA) in patients with renal allografts. We examined the differential dose effects of CYA on native renal function in 24 recipients of heart or lung transplants (treated with 7.3 +/- 0.5 mg/kg/day [mean +/- SEM]) and in seven patients with psoriasis (treated with 4.2 +/- 0.7 mg/kg/day). GFR and RPF were measured by urinary inulin and para-aminohippuric acid clearances 2 hours before the morning CYA dose and for 6 hours after. The age of heart and lung transplant recipients at renal study (2 months after transplantation) was 47 +/- 2.0 years. Their serum creatinine levels rose from 80 +/- 4.0 mumol/L during the first week after transplantation to 120 +/- 4.0 mumol/L at renal study (p < 0.0001). Their GFR and RPF were decreased before the CYA dose at 64 +/- 2.4 and 340 +/- 16 ml/min per 1.73 m2 and did not vary during the study. In comparison, the age of patients with psoriasis was 51 +/- 4.6 years at renal study (24 +/- 4.0 months after CYA treatment). Their serum creatinine levels rose from 80 +/- 4.0 mumol/L before treatment to 100 +/- 10 mumol/L at renal study (p = 0.07). Transient decreases of their baseline GFR and RPF (85 +/- 7.4 and 380 ml/min per 1.73 m2) with a nadir occurring during the first 2 hours of CYA ingestion were observed together with the recovery of these parameters toward baseline by the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk factors for renal osteodystrophy: a multivariant analysis

To assess the risk factors associated with renal osteodystrophy, we examined the database of 256 patients who were prospectively studied in three Toronto dialysis centers between October of 1987 and 1989. The potential risk factors examined included age, sex, type and duration of dialysis, type and dose of phosphate binders, vitamin D treatment, and history of diabetes mellitus, renal allograft failure, parathyroidectomy, and bilateral nephrectomy. All patients had undergone a bone biopsy and were categorized into one of four disease groupings: (1) osteitis fibrosa and mixed bone disease, (2) aluminum bone disease, (3) mild bone disorder, and (4) aplastic bone disorder. The mean (+/- SD) age of the patients at bone biopsy was 57 +/- 15 years, and 62% were men. Forty-five percent of patients were treated by hemodialysis and 55% by peritoneal dialysis. The mean duration of dialysis was 4 +/- 4 years. Twenty-five percent were also diabetic. The most common disorder was the aplastic (or "adynamic") bone disorder, found in 34% of patients. Aluminum bone disease was found in 27%, osteitis fibrosa or mixed bone disease in 27%, and mild bone disorder in 12% of patients. Cumulative intake of aluminum gels was associated with aluminum bone disease, whereas peritoneal dialysis with supraphysiologic calcium concentrations, ingestion of calcium carbonate, and diabetes mellitus were associated with both mild bone disorder and aplastic bone disorder. These three latter risk factors may be important in predisposing patients to a low bone turnover state through modulation of parathyroid hormone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Steroid therapy and prognosis of focal segmental glomerulosclerosis in the elderly

Idiopathic focal segmental glomerulosclerosis (FSGS) is an infrequent renal biopsy diagnosis in the elderly. In our single-centre referral registry there were only 17 cases seen in 822 biopsies performed in patients aged 60 or over giving an incidence of 2%. These seventeen patients ranged from age 61 to 78 at the time of biopsy and were followed a median period of 29.5 months. The incidence of nephrotic syndrome at baseline was similar to younger adults (70.5%), but both hypertension (71%) and renal insufficiency (53%) were higher. Fifty-three percent (9/17) of the patients were treated with either steroids or a combination of steroids and cytotoxic therapy. A complete remission in proteinuria was observed in 44% of the treated patients versus none in the untreated patients. No relapses were seen in those that had a complete remission. As well, none of the patients with a complete remission, versus 9/14 (63%) of the untreated or non-responsive patients progressed to renal failure during the observation period. One patient who was treated with cytotoxic therapy and steroids subsequently died of a pancreatic carcinoma. Idiopathic FSGS is an infrequent glomerulopathy in the elderly but it is important given its malignant natural history. Alternate day prednisone for up to 6 months may be a reasonable approach since a complete remission in proteinuria was seen in 44% of our treated patients and this response was closely linked to a good long-term prognosis. The risks of therapy however must be carefully weighed against the potential benefit in each case because of the advanced age of these patients.

Chronic nephrotoxicity in psoriatic patients treated with low-dose cyclosporine

Chronic nephrotoxicity is a major complication in high-dose cyclosporine treatment. We examined the glomerular filtration rate, renal plasma flow, and kidney biopsies of 15 psoriatic patients treated with low-dose cyclosporine (< or = 5 mg/kg/d) for 30 months (25 to 35 months) 1 month after drug withdrawal. The mean (95% confidence interval) age of the patients in the study was 44 years (38 to 50 years). Their serum creatinine levels pretreatment and at the time of the study were 0.94 mg/dL (0.85 to 1.0 mg/dL) and 1.2 mg/dL (1.1 to 1.3 mg/dL). Seven patients had a decreased glomerular filtration rate and four of them also had a reduced renal plasma flow, below the 2.5 percentile of normal. Four patients had moderate tubulointerstitial scarring and arteriolopathy, while the remaining patients had mild structural abnormalities. The severity of acute nephrotoxicity during treatment and chronic structural injury were highly correlated (r = 0.81; P < 0.0003). Recurrent episodes of severe acute nephrotoxicity (defined as reversible increase of serum creatinine > 90% of baseline value) was a marker for moderate chronic nephrotoxicity. No correlation was found between chronic structural injury and patient age, sex, pretreatment creatinine level, blood pressure (pretreatment or during treatment), cyclosporine dose and treatment duration, and cyclosporine blood levels. In seven patients continued on cyclosporine for another 12 months (10 to 14 months), repeat studies showed no interval changes. Despite 40 months (30 to 51 months) of treatment, all but one of these seven patients (with previous hypertension and atherosclerotic vascular disease) had mild functional and structural abnormalities. None had any severe acute nephrotoxicity at any time.(ABSTRACT TRUNCATED AT 250 WORDS)

Aplastic osteodystrophy without aluminum: the role of "suppressed" parathyroid function

We evaluated 259 dialysis patients using serum parathyroid hormone (PTH, IRMA; normal range 1 to 5.5 pM or 10 to 55 pg/ml), the deferoxamine infusion test and iliac crest bone biopsy to determine the various forms of renal osteodystrophy and their risk factors. Although half of the biopsied patients had low turnover osteodystrophy, evidence of aluminum toxicity was present in only 1/3 of them. Additional risk factors for this bone lesion included treatment with peritoneal dialysis, ingestion of calcium carbonate, diabetes mellitus and advanced age. The PTH levels in patients with the aplastic lesion were significantly lower than in patients with normal or high bone turnover lesions [7.7 +/- 6.1 vs. 36.9 +/- 3.2 pM (77 +/- 61 vs. 369 +/- 32 pg/ml), P < 0.0001]. Aside from hypercalcemia, these patients were relatively asymptomatic. In a second study, 10 patients on peritoneal dialysis with the aplastic lesion had their dialysate calcium lowered from 1.62 to 1.0 mM. This resulted in a significant increase in PTH levels, from [3.7 +/- 0.8 to 10.6 +/- 1.9 pM (37 +/- 8 to 106 +/- 19 pg/ml), P < 0.001] which persisted over the nine-month observation period. In conclusion, the aplastic lesion is the most common form of renal osteodystrophy, with aluminum intoxication implicated in only 1/3 of the cases. In the remainder, factors identified include therapy with peritoneal dialysis using supraphysiological dialysate calcium, oral CaCO3 intake and diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

Extrarenal effect of cyclosporine A on potassium homeostasis in renal transplant recipients

Cyclosporine A (CyA) is known to cause hyperkalemia by impairing renal potassium excretion. However, the observation of transient and severe hyperkalemia occurring within 3 to 5 hours of CyA ingestion in several organ transplant patients led us to postulate that it might also cause a potassium efflux from the intracellular to the extracellular fluid space. We tested this hypothesis by studying 22 nondiabetic, renal transplant patients with stable renal function (serum creatine < 2.25 mg/dL) who were treated with CyA (CyA group; n = 14) or imuran and prednisone (STD group; n = 8). Eight CyA and four STD patients also were treated with a beta-blocker (BB). While at rest, fasting plasma potassium levels were sampled hourly in all patients from 8:00 am to 1:00 pm. All medications (including CyA and BBs) were given after the 8:00 am blood sampling. Venous pH, osmolality, insulin, aldosterone, epinephrine, norepinephrine, and CyA levels also were determined at 8:00 am, 11:00 am, and 1:00 pm. Urine was collected from 11:00 pm to 8:00 am prior to the study (period I) and from 8:00 am to 1:00 pm during the study (period II) for measurement of potassium excretion (standardized to a 5-hour period). A significant increase in serial plasma potassium levels was noted in the CyA + BB group only (P = 0.0006 by repeated measures analysis of variance).(ABSTRACT TRUNCATED AT 250 WORDS)

A Molecular-Based Magnet with a Fully Interlocked Three-Dimensional Structure

A compound has been synthesized with the formula (rad)(2)Mn(2)[Cu(opba)](3)(DMSO)(2).2H(2)O, where rad(+) is 2-(4-N-methylpyridinium)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, opba is orthophenylenebis(oxamato), and DMSO is dimethyl sulfoxide. It consists of two nearly perpendicular graphite-like networks with edge-sharing Mn(II)(6)Cu(II)(6) hexagons. The two networks are fully interlocked with the same topological relationship as that between adjacent rings of a necklace. The compound has three kinds of spin carriers: Mn(II) and Cu(II) ions, antiferromagnetically coupled through oxamato bridges, and rad(+) radical cations, bridging the Cu(II) ions through the nitronyl nitroxide groups and forming Cu-rad chains. The temperature dependence of the magnetization reveals that below 22.5 K, the compound behaves as a magnet.