Chelation therapy for patients with elevated body lead burden and progressive renal insufficiency. A randomized, controlled trial

BACKGROUND

Nephropathy is known to occur in persons exposed to high levels of lead, but the question of whether long-term exposure to low levels of environmental lead is associated with impaired renal function remains controversial.

OBJECTIVE

To examine whether chelation therapy slows the progression of renal insufficiency in patients with mildly elevated body lead burden.

DESIGN

Randomized, controlled trial.

SETTING

Academic medical center in Taiwan.

PATIENTS

32 patients with chronic renal insufficiency (serum creatinine level > 132.6 micromol/L [1.5 mg/dL] and < 353.8 micromol/L [4.0 mg/dL]), mildly elevated body lead burden (> 0.72 micromol [150 microg] of lead per 72-hour urine collection and < 2.90 micromol [600 microg] of lead per 72-hour urine collection [EDTA mobilization tests]), and no history of heavy lead exposure.

INTERVENTION

The treatment group received 2 months of chelation therapy; the control group received no therapy.

MEASUREMENTS

The reciprocal of serum creatinine (1/Cr) was used as an index of progressive renal insufficiency.

RESULTS

Rates of progression of renal insufficiency were similar in the treatment group and the control group during a 12-month baseline observation period (1/Cr, 0.000054 L/micromol per month compared with 0.000046 L/micromol per month; P > 0.2). After the 2-month treatment period, improvement in renal function was greater in the treatment group than in the control group. In the 12 months after the treatment period, renal insufficiency progressed more slowly in the treatment group than in the control group (1/Cr, 0.000033 +/- 0.00038 L/micromol per month compared with 0.000045 +/- 0.000038 L/micromol per month; P = 0.0030).

CONCLUSION

Chelation therapy seems to slow the progression of renal insufficiency in patients with mildly elevated body lead burden. This implies that long-term exposure to low levels of environmental lead may be associated with impaired renal function in patients with chronic renal disease.

Differential usage of VH gene segments is mediated by cis elements

Ig diversity is generated in large part by the combinatorial joining of the Ig gene segments, VH, D, and JH, that together encode the variable domain of Ig. The final Ig repertoire, however, not only reflects the diversity generated through V(D)J recombinatorial joining, but it is also the product of a number of developmental restraints and selections. To avoid such restrictions and assess the recombination potential of individual Ig gene segments, we constructed Ig heavy (H) chain microlocus plasmids, each of which contain germline coding, recombination signal, and flanking sequences of a VH, D, and JH gene segment. These plasmids allow us to assess the recombination potential of the segments in the context of their natural flanking DNA sequences, but in the absence of any higher order chromatin structure or cellular selection. We found that the frequency and extent of deletions and additions at the recombination breakpoints are similar to those observed at rearranged Ig H chain loci in intact animals. The relative frequencies of the types of rearrangements--VD-J, V-DJ, VinvD-J (invD = inverted D), and VDJ--however, differ strongly. Moreover, V81x, the most used VH gene segment in intact mice, also is overused in this plasmid assay, 15 to 30 times that of another VH segment. This result indicates that the overuse of V81x in the early B cell repertoire can be a consequence of its DNA sequence and not of cellular activities.

Aminoguanidine reduces glomerular inducible nitric oxide synthase (iNOS) and transforming growth factor-beta 1 (TGF-beta1) mRNA expression and diminishes glomerulosclerosis in NZB/W F1 mice

Over-expression of iNOS is implicated in the pathogenesis of glomerulonephritis in animal models of systemic lupus erythematosus. The aim of this study was to evaluate the effect of aminoguanidine, a selective inhibitor of iNOS, for the protection from glomerulosclerosis in NZB/W F1 mice. Female NZB/W F1 mice (n = 8) were treated with aminoguanidine (1 g/l) in drinking water for 4 months starting at age 2 months before the onset of glomerulonephritis. Controls were age- and sex-matched mice (n = 10) without aminoguanidine treatment. By glomerular microdissection and reverse-transcription competitive polymerase chain reaction, we found that glomerular iNOS/beta-actin and TGF-beta1/beta-actin mRNA ratios were reduced 15.1% (P<0.05) and 61.3% (P<0.01), respectively, in aminoguanidine-treated mice. Aminoguanidine significantly reduced the glomerular iNOS staining, urinary nitrite production and degree of glomerulosclerosis. In addition, the glomerular volume and mean glomerular cell number were reduced 33.2% (P<0.01) and 32.8% (P<0.01), respectively. Likewise, the urinary proteinuria was also significantly reduced by aminoguanidine. These results indicate that administration of aminoguanidine may reduce the progression of glomerulosclerosis in NZB/W F1 mice, possibly through inhibition of glomerular nitric oxide production.

Multifocal retroperitoneal malignant fibrous histiocytoma: a case report

This report concerns a 67-year-old male with malignant fibrous histiocytoma arising from the psoas muscle and perirenal soft tissue. The tumor was considered a mesenchymal neoplasm. These are generally clinically and radiologically indistinguishable from other retroperitoneal tumors. This patient received en bloc resection of the retroperitoneal tumor and radical nephrectomy without adjuvant therapy. He underwent excision of a retroperitoneal cystic mass complicated with lymph leakage one year postoperatively. Discharged in a stable condition after one week of total parenteral nutrition, the patient remains disease-free 16 months postoperatively.

Poor pre-dialysis glycaemic control is a predictor of mortality in type II diabetic patients on maintenance haemodialysis

BACKGROUND

In type II diabetic patients, a better glycaemic control has been reported to slow down the progression of nephropathy. The effect of pre-dialysis glycaemic control on the long term prognosis in type II diabetics on haemodialysis is still uncertain. The purpose of this study is to evaluate the effect of glycaemic control before starting maintenance haemodialysis on the clinical outcome in type II diabetic haemodialysis patients.

METHODS

One hundred and thirty-seven type II diabetics receiving regular haemodialysis in a single university hospital were enrolled. The patients were classified as either good or poor glycaemic control group according to their glycaemic control within 6 months before starting haemodialysis. Serum albumin, haematocrit, cholesterol, triglyceride, residual renal function, diabetic complications, and patient survival were analysed in both groups.

RESULTS

There was no significant difference in age, gender, predialysis albumin level, cholesterol level, triglyceride level, and residual renal function between the two groups. The 1-year (94.5% vs 80.0%), 3-year (82.9% vs 58.1%), and 5-year (75.8% vs 21.8%) cumulative survival rates were lower in the poor glycaemic control group than in the good glycaemic control group (P < 0.001). The poor glycaemic control group also had more cardiovascular morbidity during the period of dialysis (P < 0.001). The increase in cardiovascular complications also accounted for the increased mortality during the course of haemodialysis.

CONCLUSIONS

We conclude that poor glycaemic control before starting dialysis is a strong predictor of cardiovascular morbidity and survival for type II diabetics on haemodialysis. These results imply that better glycaemic control before dialysis might be important in improving the long-term prognosis in type II diabetics on haemodialysis.

Predialysis glycemic control is an independent predictor of clinical outcome in type II diabetics on continuous ambulatory peritoneal dialysis

OBJECTIVE

To evaluate the correlation between predialysis glycemic control and clinical outcomes for type II diabetic patients on continuous ambulatory peritoneal dialysis (CAPD).

DESIGN

Sixty type II diabetic patients on CAPD were classified into 2 groups according to the status of glycemic control. In group G (good glycemic control), more than 50% of blood glucose determinations were within 3.3-11 mmol/L and the glycosylated hemoglobin (HbA1C) level was within 5-10% at all times. In group P (poor glycemic control), fewer than 50% of blood glucose determinations were within 3.3-11 mmol/L or HbA1C level was above 10% at least once during the follow-up duration. In addition to glycemic control status, predialysis serum albumin, cholesterol levels, residual renal function, peritoneal membrane function, and the modes of glycemic control were also recorded.

SETTING

Dialysis Unit, Department of Nephrology of a single university hospital.

PATIENTS

From February 1988 to October 1995, 60 type II diabetic patients receiving CAPD for at least 3 months were enrolled.

MAIN OUTCOME MEASURES

Morbidities before and during the dialysis period, patient survival, and causes of mortality.

RESULTS

The patients with good glycemic control had significantly better survival than patients with poor glycemic control (p < 0.01). There was no significant difference in predialysis morbidity between the two groups. No significant differences were observed in patient survival between the patients with serum albumin greater than 30 g/L and those with less than 30 g/L (p = 0.77), with cholesterol levels greater or less than 5.18 mmol/L (p = 0.73), and with different peritoneal membrane solute transport characteristics evaluated by peritoneal equilibration test (p = 0.12). Furthermore, there was no significant difference in survival whether the patients controlled blood sugar by diet or with insulin (p = 0.33). Cardiovascular disease and infection were the major causes of death in both groups. Although good glycemic control predicts better survival, it does not change the pattern of mortality in diabetics maintained on CAPD.

CONCLUSIONS

Glycemic control before starting dialysis is a predictor of survival for type II diabetics on CAPD. Patients with poor glycemic control predialysis are associated with increased morbidity and shortened survival.

Radiolabelling leukocytes with 99Tcm-stannous chloride colloid for the detection of inflammatory lesions

Freshly prepared 99Tcm-stannous chloride colloid (99Tcm-SCC) was used to label human leukocytes. The radiolabelled leukocytes were then injected intravenously into rats bearing carrageenan-induced inflammation in their hindlimbs. Scintigraphic imaging (n = 3) and biodistribution studies (n = 4) 4 h post-injection were performed. The ratio of radioactivity (cpm/pixel) accumulated in the inflammation site to that in the corresponding area of the contralateral limb was 2.9 +/- 0.8, as calculated by region-of-interest analyses of the planar images. The distribution of radioactivity in the dissected tissue showed that the ratio of radioactivity (cpm/g) of infected tissue to that of a normal sample obtained from the contralateral limb was 2.6 +/- 0.5. The biodistribution study of dissected organs showed high uptake in liver (58.9 +/- 8.2%), spleen (4.3 +/- 1.8%) and lungs (6.3 +/- 2.4%). The results of this preliminary study indicate that 99Tcm-SCC can be used as an alternative agent for radiolabelling leukocytes for the detection of inflammatory lesions.

Peritoneal nitric oxide is a marker of peritonitis in patients on continuous ambulatory peritoneal dialysis

Nitric oxide plays an important role in mediating the inflammatory process. The aim of this study was to evaluate if nitric oxide production was increased during peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD), and the association with the prognosis. The study population comprised 21 patients with 22 episodes of peritonitis. Fifteen patients without peritonitis were controls. Nitrate was measured by HPLC and nitrite by the Griess method, to reflect nitric oxide production. Peritoneal dialysate effluent and plasma were collected from six patients during peritonitis and 1 week after treatment to study changes in dialysate:plasma ratio. In 15 patients, nitrite was measured during peritonitis and every 3 days for 2 weeks or until normalized for evolutional changes. The dialysate:plasma ratios of nitrate and nitrite during peritonitis were reduced 26% and 41.5%, respectively, after 1 week of treatment, indicating the peritoneal production of nitric oxide during peritonitis. In the evolutional study, a 5.1-fold increase of peak nitrite levels in bacterial peritonitis (n = 13) and a 2.5-fold increase in fungal peritonitis (n = 3) were observed compared to controls. Nitrite gradually declined to control levels (9.3 +/- 7.2 days) after effective antibiotic treatment, but took longer than to normalize leukocyte count in the peritoneal dialysate effluent (3.9 +/- 1.9 days). In four patients with refractory peritonitis (Candida infection in three, Acinetobacter infection in one), the nitrite levels remained elevated 2-fold despite treatment, and the catheters were removed. It is concluded that nitrite levels in peritoneal dialysate effluent may serve as a marker to assess treatment efficacy in CAPD patients with peritonitis.

Propofol inhibits cardiac L-type calcium current in guinea pig ventricular myocytes

BACKGROUND

Propofol may exert negative inotropic and chronotropic actions in the heart. Single-channel studies show that propofol affects the kinetics of opening and closing of cardiac L-type calcium channels (ICa(L)) without altering channel conductance. The aim of this study was to investigate the mechanisms of depressant effects of propofol on cardiac whole-cell ICa(L).

METHODS

Single ventricular myocytes were freshly dissciated from guinea pig hearts using enzymatic isolation. One-suction electrode voltage-clamp technique (whole-cell mode) was used. LCa(L) was separated from other contaminated ionic currents. Propofol was applied in the commercial 10% Intralipid emulsion formula (Zeneca, UK).

RESULTS

In isolated cardiomyocytes, propofol significantly inhibited whole-cell ICa(L) in a concentration-dependent manner (K D = 52.0 microM; Hill coefficient = 1.3). The solvent (Intralipid) did not affect ICa(L). Propofol decreased ICa(L) at all potentials tested along the voltage axis and reduced the slope conductance. The threshold potential for activation and the peak potential of the current-voltage relationship were not changed by propofol. The steady-state activation curves overlapped in the absence and the presence of 56 microM propofol. In contrast, the steady-state inactivation curve was shifted in the hyperpolarizing direction. The time course of the recovery from inactivation was delayed by 56 microM propofol. The blocking action on ICa(L) of propofol shows marked resting block and use-dependent block. Propofol caused more pronounced inhibition at a higher stimulation frequency. The effect of propofol on the inactivation process was even more clear on ICa(L).

CONCLUSIONS

The authors conclude tha propofol, at supratherapeutic concentrations, inhibits cardiac ICa(L). This inhibition is mainly due to a shift of inactivation curve and a reduction in slope conductance.

B and T cells are not required for the viable motheaten phenotype

Hematopoietic cell phosphatase (HCP), encoded by the hcph gene, (also called PTP1C, SHP, SH-PTP1, and PTPN6) is deficient in motheaten (me/me), and the allelic viable motheaten (me(v)/me(v)) mice. Since HCP is expressed in many cell types and protein phosphorylation is a major mechanism of regulating protein function, it is not surprising that the motheaten phenotype is pleiotropic. It is commonly thought that immune system involvement causes this disease. If so, the motheaten disease ought to be alleviated when the recombination activation gene-1 (RAG-1) is disrupted because there will be no V(D)J rearrangement and thus impaired development of B and T cells. We bred homozygous, double-mutant me(v)/me(v) x RAG 1 -/- mice and found that, in fact, inflamed paws, and splenomegaly with elevated myelopoiesis. Thus, except for autoantibodies, the motheaten phenotype does not depend on the presence of B and T cells. This observation cautions the use of motheaten mice as a model of autoimmune disease.

Functional and urodynamic characteristics of Camey II ileal neobladder

The object of this study is to evaluate the functional and urodynamic characteristics of 16 patients who had undergone the Camey II orthotopic bladder replacement after radical cystoprostatectomy. Questionnaires regarding the voiding pattern and urinary continence were answered by 14 patients. Daytime continence was achieved in 13 of 14 patients (93%) at a mean interval of 3 months postoperatively. Eight patients (62%) attained their nighttime continence at an average interval of 10 months. Six of these 8 patients had to void to keep dry at night. Urodynamic studies were completed in 13 patients at an average of 11 months (range 6-23) postoperatively. Patients with nighttime continence had a significantly higher cystometric filling capacity (323 vs. 196 ml, p < 0.001), lower basal pouch pressure (24.5 vs. 35.2 cm water, p = 0.04), lower maximal voiding pressure (62.1 vs. 88.0 cm water, p = 0.01) and higher maximal urethral closure pressure (65.5 vs. 44.0 cm water, p = 0.03). There is no significant difference among the parameters of the age at operation, the amount of residual urine and the functional profile length between these two groups of patients. The antireflux procedure was successful in 11 of 12 patients (92%). We conclude that the Camey II operation could fulfill all the criteria of ideal bladder substitution with adequate volume, low resting pressure, satisfactory continence rate and antireflux characteristic.

Electropharmacological actions of propofol on calcium current in guinea-pig ventricular myocytes

Propofol, a widely-used intravenous anesthetic, causes bradycardia, depression in contractility and hypotension. The cellular mechanisms responsible for these cardiac toxicity remain unclear. In this study, we examined the cellular electropharmacological actions of propofol on calcium current in guinea-pig heart. Single ventricular myocytes were freshly isolated from guinea-pig using modified enzymatic method. Whole-cell voltage-clamp technique was applied with one suction pipette. Transmembrane L-type calcium current (ICa(L)) was separated from other ionic currents by voltage-control, ionic channel blockers and ion substitution methods. Our results show that propofol decreased ICa(L) in a concentration-dependent manner (KD = 54.2 microM). Slope conductance of current-voltage relation was decreased by 56 microM propofol. Propofol did not affect the steady-state activation curve, but shifted the inactivation curve to hyperpolarizing direction. Recovery from inactivation was slowed down by propofol. Marked resting block and use-dependent block were noted. In conclusion, our results indicate that propofol inhibits cardiac L-type calcium current mainly by shifting inactivation curve and retarding the recovery from inactivation.

Optimization of immunohistochemical staining of proliferating cells in paraffin sections of breast carcinoma using antibodies to proliferating cell nuclear antigen and the Ki-67 antigen

Antibodies to proliferating cell nuclear antigen (PCNA) and the MIB-1 antibody to the Ki-67 antigen were titrated to optimize identification of proliferating cells in formalin-fixed paraffin-embedded tissue from a series of 40 human breast carcinomas. Cell culture studies have previously demonstrated that immunostaining for both PCNA and the Ki-67 antigen produces strong granular nuclear staining during S phase. PC10, other anti-PCNA antibodies (PC2, PC5, PC8 and 19F4) and MIB-1 were used at the minimum dilution which allowed a clear distinction between cells with strong and weak staining. With the anti-PCNA antibodies, nickel-cobalt enhancement of the reaction product was found to augment the granular nature of nuclear staining, corresponding more closely to patterns observed in cell culture studies. No enhancement was found to be necessary for MIB-1. The labelling indices of all these antibodies were compared with S phase fraction (SPF) obtained by DNA flow cytometry in the same cases. The PC10 labelling indices which included only strongly stained cells correlated well with SPF, but counting all strongly and weakly stained cells showed a poor correlation. With MIB-1, counting strongly stained as well as all stained cells produced labelling indices which correlated well with SPF, the former tending to be lower and the latter higher. None of the other anti-PCNA antibodies showed any advantage in application over PC10. Thus, PC10 and MIB-1, applied with care, can be correlated with S phase fraction in paraffin processed tissue sections of breast carcinomas.

Characterization of the 3' untranslated region of the mouse homeobox gene HoxB5

The mouse pre-B cell line, 70Z/3, expresses multiple transcripts of the homeobox gene, HoxB5. We show here that this heterogeneity is due, at least in part, to the usage of alternative poly-A addition sites in the 3' untranslated region (UT) of the primary HoxB5 transcript. Furthermore, upon analysis of the subcellular distribution of the different HoxB5 RNA species, we found that the transcripts are present mainly in the nucleus, with two-to-five-fold less RNA present in the cytoplasm. These studies suggest that multiple post-transcriptional regulatory mechanisms are involved in the expression of HoxB5 RNA.

Pathological prognostic factors in the second British Stomach Cancer Group trial of adjuvant therapy in resectable gastric cancer

The second British Stomach Cancer Group trial was a prospective randomised controlled trial of adjuvant radiotherapy or cytotoxic chemotherapy after gastrectomy for adenocarcinoma. It recruited between 1981 and 1986. No survival advantage has been demonstrated for the patients receiving either type of adjuvant therapy compared with those undergoing surgery alone. We report on 436 patients randomised into the trial together with 203 patients, who did not fulfil the trial criteria, referred to the trial. A univariate (log-rank) analysis of pathological factors obtained from the local referring centres showed that tumour size, macroscopic type, number os sites involved, depth of invasion, involvement of resection lines and lymph nodes and histological grade were significant determinants of survival. Histological review by two experienced histopathologists found that the Lauren classification and histological grade, but not the Ming classification, were significant prognostic factors. The degree of lymphocytic and eosinophilic infiltration and presence of dysplasia assessed by one of the pathologists showed a significant correlation with survival. However, inter-observer correlation for these histological parameters and grade was poor. Multivariate analysis identified only depth of invasion, resection line and nodal involvement as significant independent pathological variables influencing survival. This study confirms the need for expert preparation of the resected specimen to obtain the important information on depth of invasion and nodal status and also reveals some variation in histological assessment, particularly grading, in gastric carcinoma.

Reduction of transiently expressed acetylcholinesterase activity in developing thalamocortical projections does not affect the mature pattern of basal forebrain projections to visual cortex

Experiments tested the hypothesis that acetylcholinesterase (AChE) activity, expressed transiently in developing thalamocortical projections, serves to limit the growth of basal forebrain cholinergic projections into thalamocortical recipient zones. Newborn rats were subjected to enucleation, a procedure that eliminates transient AChE activity in developing visual cortex. After 3-8 weeks survival, AChE histochemical techniques revealed no alteration in the pattern of AChE positive basal forebrain axons in visual cortex. These data indicate that transient AChE activity in developing sensory cortex does not limit ingrowth of basal forebrain cholinergic axons.

Neutralization of thoron progeny in gases

This paper reports charge neutralization phenomena of 212Pb particles in nitrogen or oxygen atmospheres with trace amounts of other gases. Newly produced thoron or radon progeny are positively charged, stable molecular clusters that are subsequently neutralized by several mechanisms. The charged clusters have a smaller diffusion coefficient than neutral clusters of the same size due to the interaction of the charge with the surrounding gas molecules. In this study, we have found that the diffusion coefficients of 212Pb in O2, N2, NH3/O2, NH3/N2, and C6H12/N2 (IPs between 15.58 and 9.8 eV) ranged between 0.015 and 0.030 cm2 s-1. In the case of C6H12/O2, NO2/O2, NO/O2, and dimethylamine/O2 (ionization potential between 9.8 and 8.23 eV), the diffusion coefficients have increased to between 0.046 and 0.69 cm2 s-1. These results are consistent with previous results of 218Po, indicating that charged progeny are neutralized by electron transfer from a gas molecule with a lower ionization potential than lead oxide. We estimate the ionization potential of lead oxide to range between 9.8 and 10.2 eV. 212Pb was also neutralized by an electron scavenging mechanism in NO2/nitrogen.

The role of C-reactive protein and erythrocyte sedimentation rate in the diagnosis of infected hydronephrosis and pyonephrosis

Serum C-reactive protein levels and erythrocyte sedimentation rates were prospectively evaluated in 38 patients with dilated pyelocaliceal systems in an attempt to distinguish simple hydronephrosis from infected hydronephrosis and pyonephrosis. The clinical presentations of infected hydronephrosis and pyonephrosis were extremely variable, ranging from no constitutional complaints to urosepsis. Renal sonography detected only 6 of 16 patients with pyonephrosis (specificity 96%, sensitivity 38%, accuracy 72.5%). Using a cutoff value of 3.0 mg./dl. for C-reactive protein and 100 mm. per hour for erythrocyte sedimentation rate, the diagnostic accuracy of detecting infected hydronephrosis and pyonephrosis increased to 97%, with a specificity of 89% and sensitivity of 100%. Based on our experience, we believe that the serum C-reactive protein and erythrocyte sedimentation rate levels can be used as screening tests to distinguish pyonephrosis and infected hydronephrosis from simple, uncomplicated hydronephrosis.