Subgingival microbiota of renal transplant recipients

Renal transplant patients undergoing immunosuppressive therapy may experience periodontal side-effects such as gingival overgrowth. This study evaluated the subgingival microbiota of renal transplant recipients with or without periodontal tissue destruction who may have concurrent gingival enlargement. Subgingival paper point samples taken from the deepest probing sites of 38 subjects (one per patient) were examined using direct microscopy and culture techniques. A complex microflora comprising gram-positive and gram-negative cocci, rods and filaments, fusiforms, curved rods and spirochetes was observed using microscopy. Yeasts were occasionally detected. Significantly higher proportions of gram-positive morphotypes, including gram-positive cocci, were observed in samples from periodontally healthy patients. The predominant cultivable microflora from anaerobic culture comprised several species of facultative and obligate anaerobes. Colonization of the subgingival sites by 'foreign' microbes that are normally dermal, intestinal or vaginal flora was detected in up to 50% of the samples. High mean proportions of lost or unidentified species were also occasionally noted. The results showed that the subgingival biofilm of renal transplant recipients with chronic periodontitis comprised mainly gram-negative rods and spirochetes. Besides the usual predominant cultivable subgingival microbiota associated with periodontitis, the high prevalence of unidentified and 'foreign' microbes indicates the possibility of subgingival microbial alteration in renal transplant patients.

Emodin ameliorates glucose-induced morphologic abnormalities and synthesis of transforming growth factor beta1 and fibronectin by human peritoneal mesothelial cells

OBJECTIVE

Excessive synthesis and deposition of matrix proteins by peritoneal mesothelial cells can lead to structural and functional changes in the peritoneal membrane, jeopardizing the long-term efficacy of peritoneal dialysis (PD). Prolonged exposure to high glucose concentrations in PD fluid has been implicated as a major stimulus to matrix accumulation, through the induction of transforming growth factor beta1 (TGFbeta1). This study investigated the effect of emodin (3-methyl-1,6,8-trihydroxyanthraquinone) on TGFbeta1 and fibronectin (FN) synthesis in human peritoneal mesothelial cells (HPMCs) under high glucose concentration.

DESIGN

The HPMCs were preconditioned in either 5 mmol/L or 30 mmol/L D-glucose for 2 weeks prior to the addition of emodin. Cell viability was assessed by MTT assay and lactate dehydrogenase (LDH) release. Morphology of HPMCs was studied by phase-contrast microscopy. Modulation of TGFbeta1 and FN synthesis at transcription and translation were investigated by reverse transcriptase polymerase chain reaction (RT-PCR), ELISA, and Western blot analysis.

RESULTS

When cultured under 30 mmol/L D-glucose, HPMCs demonstrated increased cell volume, multinucleation, and denudation of the monolayer, as compared with cells cultured under a physiologic (5 mmol/L) glucose concentration. High glucose concentration induced TGFbeta1 synthesis by HPMCs (217.17 +/- 14.88 pg/mL at 5 mmol/L D-glucose vs 370.33 +/- 20.67 pg/mL at 30 mmol/L D-glucose, p < 0.0001), and FN synthesis was induced at transcription and translation. Mannitol at 30 mmol/L did not affect HPMC morphology; matrix synthesis was also unaltered. Administration of emodin together with 30 mmol/L D-glucose resulted in amelioration of cell enlargement and exfoliation, and abrogation of TGFbeta1 induction (370.33 +/- 20.67 pg/mL for 30 mmol/L D-glucose alone vs 260.50 +/- 17.89 pg/mL for 30 mmol/L D-glucose + emodin, p < 0.0001). Synthesis of FN induced by high glucose was also reduced by 40% in the presence of emodin.

CONCLUSIONS

These findings provide the first evidence that emodin can ameliorate high glucose-induced matrix synthesis in HPMCs by suppression of TGFbeta1. Emodin may thus be useful in preserving peritoneal integrity in PD.

Combination gemcitabine and cisplatin chemotherapy for metastatic or recurrent nasopharyngeal carcinoma: report of a phase II study

BACKGROUND

To evaluate the efficacy and toxicity of combination gemcitabine plus cisplatin (GC) chemotherapy in metastatic or recurrent nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

Forty-four patients of Chinese ethnicity with metastatic or recurrent NPC received ambulatory GC chemotherapy every 28 days (gemcitabine 1000 mg/m(2) days 1, 8 and 15; cisplatin 50 mg/m(2) days 1 and 8). There were 40 male and four female patients with a mean age of 47.4 years. More than half (54.5%) of the patients had received either prior platinum-based chemotherapy and/or radiotherapy to target lesions.

RESULTS

There were nine complete responses and 23 partial responses in the 44 patients, achieving an overall response rate of 73% (78% for the 41 assessable patients). The mean duration of response was 5.3 months. Improved subjective symptom-control scores were found in 78% of patients with pre-existing symptoms, while 64% of patients experienced improved general well-being scores. Toxicity was mainly hematological: grade III/IV anemia, granulocytopenia and thrombocytopenia were found in 11, 37 and 16% of cycles, respectively. With a median follow-up of 17.2 months, 62% survived 1 year while 36% were alive and progression free.

CONCLUSIONS

Gemcitabine plus cisplatin chemotherapy offers a satisfactory overall response rate, subjective patient improvement and safety profile for metastatic and recurrent NPC.

Necrotizing fasciitis in a renal transplant recipient treated with FK 506: the first reported case

Necrotizing fasciitis is a rare but devastating condition usually caused by group A streptococci. A renal transplant recipient with necrotizing fasciitis complicated by the streptococcal toxic shock syndrome is presented. The importance of prompt diagnosis, antimicrobial treatment and early surgical intervention in achieving a successful outcome is discussed.

Majocchi's granuloma and posttransplant lymphoproliferative disease in a renal transplant recipient

Renal transplant recipients are predisposed to infection and malignancy because of underlying long-term immunosuppressive therapy. In this case report, a renal transplant patient with coexisting Trichophyton rubrum granuloma (Majocchi's granuloma) and posttransplant lymphoproliferative disease (PTLD) is presented, showing the undesirable effects of heavy immunosuppression. Majocchi's granuloma was probably associated with PTLD as a reflection of overimmunosuppression.

Acute pancreatitis complicating acute exacerbation of chronic hepatitis B infection carries a poor prognosis

The clinical outcome of acute pancreatitis complicating acute exacerbation of chronic hepatitis virus B (HBV) infection has never been studied. Ninety patients with acute pancreatitis were recruited. Five patients (5.6%) (Group 1) had acute pancreatitis superimposed on acute exacerbation of chronic HBV infection with no other causes of acute pancreatitis being identified. The clinical outcome of these five patients was compared to the 85 non-HBV infected patients (Group 2) with acute pancreatitis. A third group (Group 3) of patients (n=406) with acute exacerbation of chronic HBV infections without acute pancreatitis was also recruited for comparison. Group 1 had a significantly higher mortality rate (4 out of 5, 80%) compared to those of Group 2 (13 out of 85, 15.3%, P=0.0041) and Group 3 (9 out of 406, 2.2%, P < 0.0001). In Group 1 patients, the acute pancreatitis occurred during the initial rise of HBV DNA with relatively low or normal level of alanine aminotransferase (ALT) in two patients, during the rise of ALT with declining level of HBV DNA in one patient, and during the cholestatic phase of the acute exacerbation in one patient. The acute pancreatitis was clinically silent and only diagnosed by computerized tomography in the remaining patient. Direct viral damage and/or immunological attack to the pancreatic tissue were probably the underlying pathogenesis of the acute pancreatitis in these patients. In conclusion, acute pancreatitis complicating acute exacerbation of chronic HBV infection carried an extremely poor prognosis with high mortality.

Tuberculosis infection in Chinese patients undergoing continuous ambulatory peritoneal dialysis

A retrospective study of the prevalence and pattern of tuberculosis in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) was performed. Thirty-eight cases of tuberculosis were diagnosed among 790 patients (18 men, 20 women; mean age, 58 +/- 12.6 years) between July 1994 and June 2000. The interval between the initiation of CAPD and onset of tuberculosis ranged from 1 to 168 months (median, 22 months). There were 18 cases of pulmonary tuberculosis, 14 cases of tuberculous peritonitis, 5 cases of tuberculous lymphadenitis, and 1 case of tuberculous synovitis. Patients with pulmonary tuberculosis usually presented with fever, constitutional symptoms, and pleural effusion or pulmonary infiltrates on chest radiograph. Abdominal pain and turbid dialysate were the main presenting symptoms in patients with tuberculous peritonitis. Diagnosis was established by positive culture in 20 patients, typical histological characteristics on a tissue biopsy specimen in 10 patients, and response to empirical antituberculous treatment in 8 patients. The duration of symptoms before the diagnosis of tuberculosis and initiation of antituberculous treatment ranged from 7 to 57 days (median, 30 days). Antituberculous treatment consisted of isoniazid, rifampicin, pyrazinamide, and ofloxacin for 9 to 15 months. Antituberculous treatment generally was well tolerated. Twenty-seven patients (71%) completed antituberculous treatment. No recurrence of tuberculosis was observed after a mean follow-up of 19.8 months. Eleven patients (29%) died while on antituberculous treatment; none of the deaths appeared to be directly caused by tuberculosis. We conclude that: (1) tuberculosis is prevalent among CAPD patients in our locality; (2) extrapulmonary tuberculosis, particularly tuberculous peritonitis, is common; and (3) a high index of suspicion for tuberculosis among CAPD patients is warranted to ensure early diagnosis and prompt initiation of treatment.

CAPD-associated peritonitis caused by Alcaligenes xylosoxidans sp. xylosoxidans

Alcaligenes xylosoxidans is an uncommon cause of peritonitis in patients on maintenance continuous ambulatory peritoneal dialysis (CAPD). Peritonitis caused by A. xylosoxidans usually carries a poor prognosis because of the pathogen's virulence and its universal resistance to most antimicrobial agents. Even after early Tenckhoff catheter removal, the transport property of the peritoneum is often irreversibly damaged, leading to permanent technique failure. We report 2 patients with CAPD-associated peritonitis due to A. xylosoxidans sp. xylosoxidans who were successfully cured with a combination of piperacillin and tazobactam. One of them subsequently returned uneventfully to CAPD.

Progressive demyelinating neuropathy after initiation of continuous ambulatory peritoneal dialysis--report of two cases

We report on two patients who developed rapidly progressive demyelinating neuropathy within 6 to 10 weeks after the initiation of continuous ambulatory peritoneal dialysis. The neuropathy in one patient resolved after kidney transplantation while that of the other patient improved with immunosuppressive therapy. The close temporal relationship between the initiation of peritoneal dialysis and the onset of neuropathy suggests that these two events may be causally related.

Relationship between adequacy of dialysis and nutritional status, and their impact on patient survival on CAPD in Hong Kong

OBJECTIVE

Superior patient survival on continuous ambulatory peritoneal dialysis (CAPD) with 3 x 2-L exchanges has been reported from Hong Kong. This study examined the relationship between indices of dialysis adequacy and nutrition and patient survival on CAPD in Hong Kong.

DESIGN

A cross-sectional study on prevalent CAPD patients. Patients were assessed for indices of dialysis adequacy and nutritional status with a composite nutritional index (CNI). Patients were then followed for 24 months. Survival data were analyzed according to adequacy indices and nutritional status.

SETTING

All prevalent CAPD patients in nine dialysis centers in Hong Kong as of 1 April 1996.

MAIN OUTCOME MEASURE

Mortality.

RESULTS

937 patients were assessed: 68.2% were using 3 x 2-L exchanges per day; mean age was 54.6 +/- 13 years. Mean total Kt/V was 1.83 +/- 0.42 and total creatinine clearance was 55.6 +/- 19.5 L/week/1.73 m2. 19% of patients were moderately to severely malnourished according to the CNI. There was no significant correlation between indices of adequacy and serum albumin or CNI. The 1- and 2-year patient survival from the time of assessment was 90.9% and 79.8%. There was a trend toward better survival in patients with Kt/V greater than 2.0, but it was not statistically significant. Peritoneal Kt/V did not impact survival in anuric patients. Malnourished patients had poorer survival than patients who were better nourished (p = 0.0259). After adjusting for age and diabetes, CNI was predictive of mortality but Kt/V and creatinine clearance were not.

CONCLUSIONS

This study demonstrates the importance of nutritional status over adequacy indices in predicting patient survival. There was a lack of correlation between nutritional status and conventional indices of dialysis adequacy.

Increased survival of mesothelial cells from the peritoneum in peritoneal dialysis fluid

Peritonitis remains the most important factor in patient morbidity and technical failure associated with continuous ambulatory peritoneal dialysis (CAPD). In vitro examination of bacterial infection of cultured human peritoneal mesothelial cells (HPMC) is an attractive approach to the study of peritonitis in CAPD, yet there are few reports on this subject. Previous studies have shown two limitations: (i) cell cultures of HPMC lasted for days only when incubated in culture medium and (ii) short-term studies of <30 min were done in HPMC when incubated with peritoneal dialysis fluid (PDF). Human peritoneal mesothelial cells, maintained in a conventional single chamber culture system with PDF alone, were unable to survive more than 40 min. The present study was designed to prolong the viability of HPMC cultured in PDF, with the object of using cells under different conditions, such as that of simulating CAPD. HPMC were cultured using plastic microtiter plates, where they were grown to confluence and growth was arrested. PDF containing different concentrations of NaHCO3and human serum albumin was added. Cell viability after exposure for up to 24 h was measured by trypan blue, Cell Death Detection ELISA and Annex-V flow cytometry. The data confirmed the 'toxic' effect of PDF, with cell viability being <40% after 2 h incubation in 4.25% glucose in PDF. However, the survival time of HPMC increased significantly in 4.25% glucose PDF at a physiological pH and even further after the addition of human albumin. These experimental conditions simulating CAPD may allow future in vitro studies of mesothelial physiology and peritonitis related to CAPD treatment.

Effect of mycophenolate mofetil on nitric oxide production and inducible nitric oxide synthase gene expression during renal ischaemia-reperfusion injury

BACKGROUND

Recent animal data suggest that inducible nitric oxide synthase (iNOS) derived nitric oxide (NO) plays an important role in the pathogenesis of renal ischaemia-reperfusion injury (IRI) and that inhibition of iNOS ameliorates IRI. Mycophenolate mofetil (MMF), a lymphocyte selective anti-proliferative agent, has been shown to inhibit NO production in vitro. The aim of this study is to evaluate the effect of MMF on NO production and iNOS gene expression in vivo during renal IRI.

METHODS

Renal IRI was induced by clamping the left renal pedicle of male BALB/c mice for 30 min, followed by 15 min of reperfusion. The mice received placebo or MMF at 40, 80 or 120 mg/kg/day by oral gavage for 5 days before the operation. Sham-operated mice served as the operation control. The amount of NO produced and the level of iNOS gene expression in the kidney tissue during IRI was assessed by spin trapping electron paramagnetic resonance (EPR) spectroscopy and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) respectively.

RESULTS

In the sham-operated kidneys, only low levels of NO and iNOS mRNA were detected. In mice with renal IRI, the amount of NO detected was significantly increased, which was reduced in a dose dependent fashion by pre-treatment with MMF. Pre-treatment with MMF also substantially reduced iNOS gene expression in the kidney tissue.

CONCLUSIONS

We conclude that pre-treatment with MMF inhibits the production of NO and the induction of iNOS gene expression in the kidney during IRI. These results suggest that MMF might have the potential to ameliorate renal IRI.

In vitro studies of aquaporins 1 and 3 expression in cultured human proximal tubular cells: upregulation by transferrin but not albumin

Dysregulated renal water handling is a cardinal feature of nephrotic syndrome that has been shown in animal models of experimental nephrosis to mediate renal aquaporin (AQP) expression. However, data on the effect of proteinuria on the proximal tubule, which is heavily vested with AQP1 and therefore may participate in water homeostasis, are limited. To investigate this, we exposed primary human proximal tubular epithelial cells (PTECs) to two key proteinuric components shown to perturb tubule function: human serum albumin and transferrin. Using reverse-transcriptase polymerase chain reaction and immunocytochemical techniques, PTECs in the quiescent state were found to express AQP3 in addition to AQP1 gene and protein, which was also validated in a human proximal tubule cell line, HK-2. Immunohistochemical staining localized AQP1 synthesis to the apical and basolateral membranes and AQP3 synthesis to the basolateral membrane of proximal tubule epithelium. Transferrin in doses reaching nephrotic range upregulated PTEC transcription and translation of both AQP1 and AQP3 in a time- and dose-dependent manner. After 24 hours of stimulation, transferrin led to a 2.4- and 2.2-fold increase in AQP1 and APQ3 messenger RNA expression, whereas protein synthesis surged by 40.7% +/- 2.48% and 24.2% +/- 0.9% compared with control, respectively. These effects were not observed with albumin challenge and were not caused by osmolality fluctuation with transferrin treatment. In summary, our novel finding of AQP3 in PTECs indicates a role for AQP3 in proximal tubule water reabsorption. The pathophysiological significance of heightened AQP1 and AQP3 expression in PTECs on protein challenge as occurs in the nephrotic state requires further investigation.

Structural characterization of the oxidative degradation products of an antifungal agent SCH 56592 by LC–NMR and LC–MS

LC-NMR and LC-MS were used to characterize the structures of four major degradation products of SCH 56592, an antifungal drug candidate in clinical trials. These compounds were formed under stress conditions in which the bulk drug substance was heated in air at 150 degrees C for 12 days, and were separated from SCH 56592 as a mixture using a semi-preparative HPLC method. The data from LC-NMR, LC-ESI-MS (electrospray ionization mass spectrometry) and LC-ESI-MS/MS indicate that the oxidation occurred at the piperazine ring in the center of the drug molecule. The structures of the degradation products were determined from the 1H NMR spectra obtained via LC-NMR, which were supported by LC-ESI-MS and LC-ESI-MS/MS analyses. A novel degradation pathway of SCH 56592 was proposed based on these characterized structures.

Electrophysiology and glucose transport of human peritoneal mesothelial cells: implications for peritoneal dialysis

OBJECTIVE

To elucidate ionic and glucose transport across human peritoneal mesothelium, we utilized an Ussing chamber setup and studied the electrophysiological characteristics and tissue permeabilities of human peritoneal mesothelial cells (HPMC) to L- and D-glucose.

METHODS

Human mesothelial cells were grown on polyester filters (snapwell; Costar, Cambridge, MA, U.S.A.) that, upon confluence, were fitted into Ussing chambers. Transmesothelial resistance and resting potential were determined using electrophysiological techniques. Radiolabeled glucose was added to one side of the chamber and the permeabilities determined by serial sampling in the receptive compartment.

RESULTS

The transmesothelial potential and resistance were 0.54 +/- 0.07 mV (apical positive) and 20.4 +/- 3.2 ohms x cm2 respectively (mean +/- SEM, n = 36). The course of overall transfer of D- and L-glucose was examined using L-glucose as a positive diffusion-plus-leak marker. The permeabilities of HPMC to D-glucose were 3.00 +/- 0.26 cm/sec (apical-to-basolateral) and 3.25 +/- 0.27 cm/sec (basolateral-to-apical) [n = 6 experiments, p = not significant (NS)], which were not different from those of L-glucose: 3.00 +/- 0.30 cm/sec (apical-to-basolateral) and 2.71 +/- 0.24 (basolateral-to-apical) (n = 6 experiments, p = NS).

CONCLUSIONS

The transepithelial resistance of HPMC is low and the ionic gradient, although it exists, is small and inconsequential. Passive paracellular flow accounts for the majority of transmesothelial glucose transport. The existence of a large paracellular shunt precludes the mesothelial membrane as a clinically relevant osmotic barrier.

Nosocomial outbreak of parvovirus B19 infection in a renal transplant unit

BACKGROUND

Parvovirus B19 (B19) infection is known to cause chronic infection leading to anemia in immunocompromised patients. Although nosocomial B19 infections in immunocompetent patients have been documented, no outbreaks in immunocompromised patients have been previously reported. Whether transmission can occur from a patient with chronic infection is also unknown.

METHODS

An outbreak of B19 infection in a renal transplant unit was investigated by molecular analysis of the virus strains and a case-control study.

RESULTS

Three patients had genetically identical virus strains suggesting the occurrence of nosocomial transmission. The index case transmitted infection many weeks after the onset of her clinical symptoms. Other patients at risk of acquiring infection were those most intensively immunosuppressed. Viral load in the serum correlated with the hematological response. A rebound in the viral load was associated with clinical relapse and the failure of i.v. immunoglobulin therapy.

CONCLUSION

Nosocomial transmission of B19 can occur from immunocompromised patients even when they are in the chronic stage of the infection. The clinical and virological response to i.v. immunoglobulin therapy is variable and depends on the overall level of immunosuppression of the patient.

Transferrin but not albumin mediates stimulation of complement C3 biosynthesis in human proximal tubular epithelial cells

Complement is increasingly implicated in the pathogenesis of progressive renal disease resulting from persistent proteinuria. We have previously shown that apical serum proteins stimulate C3 in cultured human proximal tubular epithelial cells (PTECs), and that the stimulant is a nonalbumin compound of 30 to 100 kd. We postulated in this study that transferrin and apotransferrin, also important components of proteinuric urine in this molecular-weight range, might be the culprit. Human PTECs were obtained by differential sieving of renal cortical tissue from the normal pole of tumor nephrectomy specimens and characterized to be predominantly of proximal tubular origin. Complement C3 messenger RNA (mRNA) expression was analyzed in confluent growth-arrested PTEC monolayers in media containing different concentrations (2.5 to 20 mg/mL) of transferrin by reverse transcription and polymerase chain reaction. Pure human albumin was used as a control protein. C3 protein secretion was detected and quantified by a sandwich enzyme-linked immunosorbent assay on cell culture supernatants after distinct time points. Transferrin enhanced the rate of C3 secretion in a dose-dependent manner, reaching maximal stimulation at doses of 10 mg/mL. Selected experiments using the Transwell technique showed that C3 release was predominantly apical in the resting state. The addition of 10 mg/mL of transferrin apically but not basolaterally stimulated both apical and basolateral C3 secretion and increased the basolateral-apical ratio of C3 secretion from 0.45 +/- 0.16 to 0.93 +/- 0.24 (P: < 0.02). Constitutive C3 mRNA expression was upregulated by transferrin in a time- and dose-dependent fashion, reaching a peak after 24 hours. A similar degree of C3 upregulation was reproduced when iron-poor transferrin, apotransferrin, was used instead. These results indicate that C3 synthesis in PTECs is upregulated by transferrin, for which protein rather than iron moiety may account for the observed effects. These findings provide evidence linking proteinuria with overexpression of tubular complement.