Erythropoietin and erythropoiesis in renal transplantation

This report reviews the features of erythropoietin (Epo) production after renal transplantation. Successful kidney transplantation leads to the correction of renal anaemia over an 8-10 week period. An early ineffective peak of serum Epo may occur when there is delayed graft function. A late peak follows the decrease in serum creatinine and this is associated with a rise in haemoglobin. Serum Epo returns to normal when the haematocrit reaches 32%. Acute early rejection causes a striking reduction in serum Epo and reticulocytosis. In some patients the haematocrit continues to increase after complete correction of anaemia, resulting in post-transplant erythrocytosis (PTE). PTE generally appears to be an idiopathic erythrocytosis independent of Epo secretion. A greater Epo sensitivity of erythroid progenitors has been suggested. Theophylline and angiotensin converting enzyme inhibitors, which attenuate Epo production, can be used to treat PTE. The second part of this report describes the possible impact of human recombinant Epo (rHuEpo) on renal transplantation. The avoidance of blood transfusion with rHuEpo should eliminate the initiation of anti-HLA sensitization in uraemic patients without previous pregnancy and prior allograft. In some but not all presensitized patients transfusion withdrawal may reduce the sensitization level. There is currently no evidence that the reversing of anaemia by rHuEpo in kidney recipients impairs early graft function. Our results suggest that treatment with rHuEpo prior to transplantation may prevent the appearance of PTE. rHuEPO will reverse anaemia in patients with a failing graft and severe anaemia with little risk of accelerating graft failure and adverse events.

Serum secretory IgA and IgM and free secretory component in IgA nephropathy

IgA nephropathy (IgAN) is characterized by the presence of IgA and C3 deposits in the mesangium. Mesangial IgA is mostly dimeric IgA1 with a J chain, lacking a secretory component. In view of the recent demonstration of elevated serum levels of secretory component and secretory IgA in liver disease and HIV infection associated with hyper-IgA, we measured the serum secretory component in 50 IgAN patients and 45 controls. Free secretory component and secretory IgA and IgM levels were determined by enzyme-linked immunosorbent assay. Normal or low levels were found patients. These data support previous work suggesting that in IgAN circulating and probably mesangial IgA do not originate from the epithelial compartment of the mucosal immunoglobulins as it is the case in other hyper-IgA diseases.

Stable maintenance of glutamate receptors and other synaptic components in long-term hippocampal slices

Cultured hippocampal slices retain many in vivo features with regard to circuitry, synaptic plasticity, and pathological responsiveness, while remaining accessible to a variety of experimental manipulations. The present study used ligand binding, immunostaining, and in situ hybridization assays to determine the stability of AMPA- and NMDA-type glutamate receptors and other synaptic proteins in slice cultures obtained from 11 day postnatal rats and maintained in culture for at least 4 weeks. Binding of the glutamate receptor ligands [3H]AMPA and [3H]MK-801 exhibited a small and transient decrease immediately after slice preparation, but the binding levels recovered by culture day (CD) 5-10 and remained stable for at least 30 days in culture. Autoradiographic analyses with both ligands revealed labeling of dendritic fields similar to adult tissue. In addition, slices at CD 10-20 expressed a low to high affinity [3H]AMPA binding ratio that was comparable with that in the adult hippocampus (10:1). AMPA receptor subunits GluR1 and GluR2/3 and an NMDA receptor subunit (NMDAR1) exhibited similar postcutting decreases as that exhibited by the ligand binding levels, followed by stable recovery. The GluR4 AMPA receptor subunit was not evident during the first 10 CDs but slowly reached detectable levels thereafter in some slices. Immunocytochemistry and in situ hybridization techniques revealed adult-like labeling of subunit proteins in dendritic processes and their mRNAs in neuronal cell body layers. Long-term maintenance was evident for other synapse-related proteins, including synaptophysin, neural cell adhesion molecule isoforms (NCAMs), and an AMPA receptor related antigen (GR53), as well as for certain structural and cytoskeletal components (e.g., myelin basic protein, spectrin, microtubule-associated proteins). In summary, following an initial and brief depression, many synaptic components were expressed at steady-state levels in long-term hippocampal slices, thus allowing the use of such a culture system for investigations into mechanisms of brain synapses.

Tuberculosis of the breast: US, mammographic, and CT findings

A case of tuberculosis of the breast is presented. The mammographic, ultrasound, and CT appearances are described.

Renal transplantation in patients over sixty years of age

The aim of this study was to analyze whether old age affects the outcome of renal transplantation. Data were presented on all 337 renal allografts performed from January 1, 1987 to November 30, 1992 in the department of Nephrology and Urology, University Hospital of Nancy. Of these, 32 (9.5%) were performed in patients over 60 years old at the time of transplantation (mean duration of follow-up 22.3 +/- 17.1 months). No significant difference was noted in patient and graft survivals between the two groups at 36 months (respectively 83.8% and 76.1% in elderly patients; 96% and 82.8% in younger recipients). In the older group, all grafts were lost due to death (2/5) or nephrectomy (3/5) with a functional transplant (3/5) whereas chronic rejection accounted for the majority of graft loss in the younger group (23/43, p < 0.05). Episodes of acute rejection occurred with a very low incidence in elderly patients (15.6%). Infections were infrequent in this group and did not represent serious complications. Functional rehabilitation and quality of life were as good in elderly as in younger recipients. These results suggest that renal transplantation is an acceptable form of treatment for patients older than 60 years with end-stage renal disease in the absence of obvious contraindication.

Experimental articular toxicity of aluminum compounds in vivo

OBJECTIVE

To investigate the articular toxicity of 2 aluminum derivatives, one insoluble (hydroxide) and/or the other soluble (lactate), after a single administration in rabbits and rats.

METHODS

First, aluminum levels in plasma, urine, synovial tissue, liver and kidney were measured in saline treated rabbits and 1 to 2 days after an articular injection of 75 mg of aluminum compounds into their right knee. The methodology used was argon plasma emission spectrometry. Thereafter, the joint toxicity of aluminum lactate at the same dose regimen was evaluated for 2 days by a qualitative histological examination of synovial tissue and articular surfaces and a colorimetric assay (1,9-DMB) of patellar articular cartilage proteoglycan content. Secondly, the single injection of 50 mg of aluminum derivatives as an inducer of inflammation was studied in the rat subcutaneous air pouch, a model for a synovial-like space. Leukocytes and eicosanoids levels were measured in pouch washout fluids from 1 to 72 h after injection.

RESULTS

After injection into rabbit knee, aluminum lactate largely distributed within the body while hydroxide remained locally. However, aluminum lactate resulted in perivascular edema, sparse infiltration of inflammatory cells in the synovium and a hemorrhagic effusion. Proliferation of the synovial cell layer coexisted with an apparent loss of proteoglycan in superficial zones of tibial and femoral cartilages when patellar proteoglycan content remained unchanged. Aluminum hydroxide did not affect joint structures. In the air pouch experiment, aluminum lactate increased prostaglandin E2 (PGE2) levels from 3 to 10 h after its injection and less intensively leukotriene B4 (LTB4) levels after 6 h, in the absence of leukocytes migration into the cavity. In contrast, aluminum hydroxide increased leukocytes count in pouch-washout fluid from 3 to 24 h after its injection when PGE2 and LTB4 levels were little modified.

CONCLUSION

Although some differences attributable to dissimilarities in the experimental model used, aluminum compounds, even in a soluble form, may damage joint structures either directly or through stimulating the secretion of eicosanoids by synovial-like cells.

Kainate binding to the AMPA receptor in rat brain

Displacement of [3H]AMPA and [3H]CNQX by kainate was measured in membranes and solubilized fractions from rat brain. In soluble fractions, plots of [3H]AMPA and [3H]CNQX binding displaced by kainate resulted in one-site fits with Ki values in the range of 1-3 microM. In membranes, plots of [3H]AMPA binding displaced by kainate resulted in graphs which were better fit by two-site regression analysis than by a one-site fit. The Ki value for the high-affinity component of these two-site fits was 3-9 microM and the low-affinity component Ki was in the range of 70-120 microM; similar values were determined for kainate displacement of [3H]CNQX. The presence of thiocyanate ions had no effect on kainate displacement of [3H]CNQX. Since the affinity for kainate of the presumed synaptic AMPA receptor is in the range of EC50 values for kainate determined from physiological studies, these data contribute further evidence for the idea that kainate binding to synaptic AMPA receptors may be responsible for many of kainate's physiological effects.

A centrally active drug that modulates AMPA receptor gated currents

Systemic administration of the drug 1-(1,3-benzodioxol-5-ylcarbonyl)-piperidine (1-BCP) has been reported to enhance monosynaptic responses in the hippocampus in vivo and to improve spatial and olfactory memory in rats. The drug's mechanism of action was investigated in the present study using membrane patches excised from cultured hippocampal slices. The decay time of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor mediated inward currents was greatly increased by 1-BCP in a concentration dependent and reversible fashion; peak current was also enhanced but to a lesser degree. In vitro slice experiments indicated that the drug has parallel effects on the field EPSP. It is concluded that 1-BCP is a centrally active modulator of the AMPA receptor.

[Epidemiology and results of organ grafts]

Using the complete, multicentric Registry of organ transplantation in France, from 1970 to 1992, including 26,485 transplantations (kidney, heart, heart-lungs, lungs, liver), we studied four statistical parametres: 1. movement on the waiting list; 2. mean waiting time; 3. actuarial survival of the graft for the kidney, heart and liver; 4. number of recipients surviving with a functioning graft as of 31 December 1992. Patients awaiting a kidney transplant comprise a group that differs epidemiologically from the others on the basis of the length of the waiting list, entering and existing flux, and for the mortality rate of patients waiting for a graft. Similarly, the actuarial survival profile is different for the first year in kidney transplant recipients compared to the others.

Stimulation of NMDA receptors activates calpain in cultured hippocampal slices

The hypothesis that intense stimulation of NMDA receptors activates calpain was tested in long-term cultures of hippocampus. Slices prepared from 10-day-old rats were maintained for periods of up to 6 weeks and then assayed for a stable breakdown product that results from the proteolysis of spectrin by calpain. The breakdown product increased dramatically during the first 24 h after tissue preparation and then decreased to a low level that remained unchanged for weeks. NMDA caused a 2- to 3-fold increase in breakdown product that rose linearly with time (5-30 min) and was blocked by the receptor antagonist MK-801. The effect of NMDA was the same throughout the culture period and was dependent upon the concentration of extracellular calcium with no effect at 2 mM and maximal effect at 4 mM calcium. These results indicate that rapid activation of calpain occurs in undamaged hippocampal neurons following stimulation of NMDA receptors.

[Mesangial IgA deposits nephropathy]

Idiopathic IgA nephropathy of Berger's disease is characterized by prominent and diffuse IgA deposits in the mesangium. In many countries, it is the most common type of primary chronic glomerulonephritis. Typically, it is revealed by recurrent episodes of gross hematuria in association with ENT infection, but it can progress insidiously with microscopic hematuria and proteinuria. Serum IgA levels are increased in about 50% of cases. IgA nephropathy is not a minor condition: 20% of patients develop end-stage chronic renal failure 10 years after diagnosis and 50% after 20 years. IgA nephropathy can recur in a transplanted kidney suggesting that this disease is a systemic disorder although it has a remarkable tropism for the kidney. Even though many points remain to be elucidated, its pathogenesis appears to be linked to a genetic factor responsible for a lymphocyte dysfunction and an acquired environmental factor such as penetration of an antigen via the mucosa which may give rise to an excessive and inappropriate IgA immune response with the deposition of IgA in the mesangium and the development of progressive renal alterations. No treatment has been shown to be effective but tonsillectomy advised in case of a recurrent tonsillar focal infection is most often accompanied by a decrease in the incidence of gross hematuria. Corticosteroid therapy can be of benefit in cases involving a nephrotic syndrome associated with minimal glomerular lesions. In all cases, control of possible hypertension is of value in slowing the progression of this disease.

[Acute postoperative renal insufficiency in renal transplantation. Incidence and risk factors]

Delayed renal function (DFG) is known to influence both the short and long-term outcome of transplanted kidneys. Data collected retrospectively on all 129 cadaveric renal transplants performed between January 1991 and January 1993 within a single center were analyzed. 42 (32.55%) cases of acute renal failure (ARF) occurred during the immediate postoperative period and 28 patients required dialysis. When compared with immediate good allograft function, DGF was associated with previous failed transplant (7/15 vs 35/114, p = 0.01), donor age (39.2 +/- 13 vs 30.1 +/- 12 years, p = 0.01), and episodes of collapsus of the donor (11/25 vs 31/104, p < 0.01). The graft function of the recipient was not correlated with the serum creatinine of the donor. There was no apparent relationship between the cold ischemia or the anastomosis time and the occurrence of DGF. One-year patient and graft survival were similar in the two groups (respectively for the group ARF and without ARF: 96.4% and 96.5%; 88.8% and 89%), but patients with DGF had higher serum creatinine values at 12 months post DGF (185.6 +/- 44.8 mumol/l vs 157.5 +/- 30.8 mumol/l, p = 0.06). This study suggests that DGF is related to the characteristics of the donor graft and is more frequently encountered in previously transplanted recipients.

[Carcinoma of the native kidney in patients with renal transplantation. A French multicenter study]

A study was undertaken to investigate the development of carcinoma in patients' own kidneys after renal transplantation. Twenty carcinomas were diagnosed among 16,755 patients grafted from 1952 to February 1993. It was possible to collect data for 17 detected carcinomas. These tumours developed in 17 patients, 14 male and 3 female, aged 31 to 64 years old. They appeared an average of 40 (range 1-204) months after transplantation. The maintenance treatment consisted of cyclosporine in 15 recipients. Four patients demonstrated clinical signs. The other 13 carcinomas were diagnosed as an incidental finding on ultrasound (n = 10), at autopsy (n = 1) or by examination of kidneys from nephrectomy (n = 2). In the patient group with incidental diagnosis, tumors were larger than 4 cm in 3 out of the 9 cases studied; they were confined to the kidney in 5 cases and lymph node invasion or renal vein involvement were noted in 1 case. Distant metastases were present in 3 symptomatic patients and in 1 "incidental" case. Except for tumours discovered on nephrectomies or autopsy, a nephrectomy was performed in all cases. Death occurred 1 to 12 months after diagnosis in the recipients with metastatic tumours. A colic carcinoma was diagnosed 6 months after nephrectomy in one patient. The other 11 patients are doing well as the immunosuppressive treatment is being continued.

[Lymphoproliferative lesions localized in the renal graft. A French multicenter study]

Thirty-two French transplant centers participated in the study of lymphoproliferative disease (LPD) confined to the renal allograft. For the period from 1952 to February 1993, 16 cases were recognized from 16,755 renal transplant recipients. The mean age of the patients was 44 years (range 19-67 years). Fourteen of these recipients received anti-lymphocyte globulin as induction therapy and 13 received cyclosporine as their maintenance immunosuppressive treatment. Acute rejection was reported in 9 cases and was treated with methylprednisolone in 6 cases and with mono- or polyclonal antibodies for 3 episodes. The mean interval from transplantation to development of LPD was 14 months (range, 1-144 months). Most of the patient (12/15) showed symptoms. Renal failure was noted in 7 recipients. Renal ultrasound demonstrated hydronephrosis in 4 cases, a hilar mass in 5 cases, a mass lesion within the graft in 2 cases. Pathological examination showed a high grade malignant lymphoma with extensive necrosis and atypical large cells. Immunohistochemical study was consistent with B-cell lymphoma in all of the 8 cases analyzed and monotypia was noted in 4 cases. The presence of Epstein-Barr virus genome in the LPD was demonstrated in 5 of the 6 cases studied. Nine patients were managed with discontinuation of immunosuppression and transplant nephrectomies. Four patients died. The remaining recipients are alive with no evidence of recurrence after 25 months (range 3-68 months).

Cyclothiazide decreases [3H]AMPA binding to rat brain membranes: evidence that AMPA receptor desensitization increases agonist affinity

The effects of cyclothiazide, a drug which blocks AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor desensitization, were tested on binding of [3H]AMPA to rat brain membranes. Cyclothiazide reduced [3H]AMPA binding by lowering the apparent affinity of the AMPA receptor. The magnitude of the decrease was temperature dependent and greater for membrane-bound than for solubilized receptors. These data provide evidence that desensitization increases the affinity of the AMPA receptor for agonists and indicate that a significant percentage of AMPA receptors in conventional equilibrium binding assays are in a desensitized state.