Polyneuropathy associated with cholesterol crystal embolism.

INTRODUCTION: Cholesterol crystal embolism complicating arterial catheterization usually presents as a multiorgan disease with renal failure, abdominal problems, and skin manifestations. METHODS: We present a patient with hypertension and generalized arteriosclerosis who presented with muscle weakness, diffuse pain in the extremities, and renal failure 3 weeks after coronary catheterization and angioplasty of the right coronary artery. Muscle weakness progressed during the following months. RESULTS: Nerve conduction studies and nerve biopsy showed severe axonal nerve injury. Biopsy of the kidney revealed the diagnosis of cholesterol crystal embolism. CONCLUSION: The clinical presentation indicates a direct association of cholesterol crystal embolism and polyneuropathy. Although cholesterol crystal embolism represents a rare cause of polyneuropathy, it should be considered in patients with acute onset polyneuropathy and sudden onset multiorgan disease after arterial catheterization.

Evolution of light chain deposition disease over 8 years.

A 44-year-old female was diagnosed with proteinuria due to nodular glomerulosclerosis secondary to light chain deposition disease (LCDD). After 6 years, deterioration of kidney function occurred and autologous stem cell transplantation was considered, but the patient refused specific therapies. The disease progressed slowly, over a period of 8 years reaching now chronic renal insufficiency stage 4 with a creatinine clearance of 20 ml/min, in spite of no specific therapy. This case, documented by repeated biopsies, demonstrates the very slow loss of kidney function, suggesting the possibility of conservative treatment strategies without taking the risks of chemotherapy or autologous stem cell transplantation, since no long term follow up data of these therapies are available for LCDD.

Effective treatment of hepatitis C-associated immune-complex nephritis with cryoprecipitate apheresis and antiviral therapy.

A 38-year-old pregnant woman (19th week of pregnancy) complained of fatigue, cold inducible paresthesias, generalized edema and mild arterial hypertension. Her past medical history was notable for frequent episodes of polyarthralgia and positivity for rheumatoid factor. On admission, acanthocyturia and unselective glomerular-tubular proteinuria with 19 g/d were detected with a slight decrease in creatinine clearance. Rheumatoid factor was robustly elevated and a cryocrit of 1.5 vol%, caused by a so far unknown replicative hepatitis C, was detected. Renal biopsy yielded membrano-proliferative glomerulonephritis. During pregnancy, high-dose corticosteroid therapy was administered. Edema disappeared and blood pressure normalized under albumin substitution and low-dose furosemide application. However, Cesarian section became necessary due to placental insufficiency at 27 weeks of gestation. Thereafter, neither virus load, cryocrit nor proteinuria decreased significantly under a combined therapy with pegylated interferon-a and ribavirin. Thus, cryoprecipitate apheresis was initiated resulting in robust decreases of clinical complaints, viral load, cryocrit and proteinuria. Cryoglobulinemia with renal involvement caused by hepatitis C is difficult to treat due to limitations of immunosuppressive and anti-viral therapy. In our patient, cryoprecipitate apheresis was a safe and effective therapeutic addition to standard therapy.

Thrombotic microangiopathy in a 17-year-old patient: TTP, HUS or a bit of both?

Thrombotic microangiopathies are characterized by the development of hyaline thrombi in small vessels resulting in thrombocytopenia, microangiopathic hemolysis, and organ dysfunction. Thrombotic-thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are two major clinical syndromes of thrombotic microangiopathies. Although differential diagnosis between TTP and HUS is commonly determined in the clinical setting, recent evidence suggests major pathophysiological differences between the two diseases. Autoimmune inhibitors or genetic mutations of a von Willebrand factor (VWF) cleaving metalloprotease (ADAMTS13) leads to the accumulation of unusually large multimeric forms of VWF in TTP, facilitating adherence of platelets and development of microthrombi. In contrast, classic HUS is caused by infection with verocytotoxin-producing bacteria. This toxin induces endothelial injury, apoptosis and inflammation. Endothelial injury results in increased shear-stress, fostering cleavage of VWF, but thrombosis eventually develops. One would assume that measurement of ADAMTS13 activity and/or detection of verocytotoxin could easily contribute to the differential diagnosis of TTP or HUS. We report on a case of a young patient with thrombotic microangiopathy and renal involvement with low ADAMTS13 concentrations which did not respond well to plasmapheresis therapy, but subsequent to the detection of verocytoxin producing E. coli with the serotype O157:H7, reacted well to antibiotic treatment. Sequencing of the ADAMTS13 gene revealed no mutations and no anti-ADAMTS13 antibodies could be detected. This case shows overlapping presentations as well as etiologies for both TTP and HUS, a finding also underscored by a recent animal model in which verocytoxin triggered development of TTP in ADAMTS13-deficient mice.

Plasma creatinine determination in mice and rats: an enzymatic method compares favorably with a high-performance liquid chromatography assay.

The use of the colorimetric Jaffé method for the measurement of creatinine in mouse and rat plasma has been criticized as prior studies have shown a dramatic overestimation. We compared a colorimetric picric acid, an enzymatic, and a high-performance liquid chromatography (HPLC) method to assess their appropriateness for routine measurements of creatinine in plasma of healthy and diseased mice (n=61) and rats (n=56). For the colorimetric Jaffé method a pronounced overestimation is confirmed. Additionally the method showed interference with hemoglobin already in a very low, non-visible concentration range in rat plasma. The enzymatic measurement demonstrated a hemoglobin interference in mice, only when hemolysis was visible. The comparison between HPLC and the enzymatic measurement gave a good agreement between both methods in both species. Therefore the enzymatic method fulfills the requirements for a routine screening test for plasma creatinine in healthy as well as diseased mice and rats Kiover a broad concentration range.

Pivotal role of xanthine oxidase in the initiation of tubulointerstitial renal injury in rats with hyperlipidemia.

Hyperlipidemia can induce or aggravate renal tubulointerstitial injury. Experiments in a complex rat model with chronic glomerulonephritis and long-standing, coexisting hyperlipidemia suggested that induction of xanthine oxidase (XO), with increased oxygen radical generation, is involved in aggravation of tubulointerstitial injury. To separate the role of XO in the initial events of lipid-mediated tubulointerstitial injury, short-term experiments with diet-induced hyperlipidemia over 21 and 35 days were performed in otherwise healthy rats. XO expression in relation to the antioxidant enzymes was examined in the cortical tubulointerstitium (TIS) and proximal tubules (PT). Subsequent experiments with XO inhibition were performed, examining tubulointerstitial infiltration with ED1-positive cells and expression of adhesion molecules and monocyte chemoattractant protein-1 (MCP-1) as indicators of early injurious events. Hyperlipidemia increased XO activity in TIS by 40 and 86%, and in PT by 28 and 90% at days 21 and 35, compared with controls on regular diet. This increased activity was associated with increased reactive oxygen species. Among the antioxidant enzymes, glutathione peroxidase activity increased in TIS by 40% and in PT by 90%. Histological evaluation showed a three-fold increase in ED1-positive cells and increased MCP-1 and vascular cell adhesion molecule-1 (VCAM-1) expression at day 35 in the TIS. Inhibition of XO prevented tubulointerstitial ED1 cell infiltration, together with a decreased expression of MCP-1 and VCAM-1. These results point to an important role for XO in the early stage of hyperlipidemia-associated renal injury, mediating macrophage infiltration by a putatively redox-dependent upregulation of MCP-1 and VCAM-1.

Control of neuronal branching by the death receptor CD95 (Fas/Apo-1).

The CD95 (Apo-1/Fas)/CD95 ligand (CD95L) system is best characterized as a trigger of apoptosis. Nevertheless, despite broad expression of CD95L and CD95 in the developing brain, absence of functional CD95 (lpr mice) or CD95L (gld mice) does not alter neuronal numbers. Here, we report that in embryonic hippocampal and cortical neurons in vivo and in vitro CD95L does not induce apoptosis. Triggering of CD95 in cultured immature neurons substantially increases neurite branches by promoting their formation. The branching increase occurs in a caspase-independent and death domain-dependent manner and is paralleled by an increase in the nonphosphorylated form of Tau. Most importantly, lpr and gld mutants exhibit a reduced number of dendritic branches in vivo at the time when synapse formation takes place. These data reveal a novel function for the CD95 system and add to the picture of guidance molecules in the developing brain.

Unusual profile and high prevalence of p53 mutations in esophageal squamous cell carcinomas from northern Iran.

Over 15,000 human tumor p53 mutations have been recorded in the scientific literature, including over 700 mutations in esophageal tumors. There are no data on p53 mutations in esophageal cancer patients from Iran yet; however, this country experiences one of the highest cancer mortality rates in the world for esophageal squamous cell carcinomas (ESCCs). The causes of this high cancer burden in Iran remain obscure and do not appear to be related to tobacco and alcohol consumption, the two major risk factors identified in Europe and North America. Because molecular analysis of tumors can provide clues to endogenous or environmental factors contributing to high cancer risk, we examined 74 Iranian ESCCs for the presence of mutations in exons 5-8 of the p53 gene by PCR and direct sequencing. Forty-eight of the 74 tumors (65%) had one or more p53 gene point mutations, including 5 patients with two or more mutations and one with a tandem mutation in codon 242. Surprisingly, over one-third of the 54 mutations we identified were transitions at CpG sites (20 of a total of 54 mutations, or 37%), a class of mutation that is significantly less common (16% of mutations) in the compilation of ESCC mutations from other countries (chi2 statistic, P < 0.0002), whereas transversions, which the literature shows to be common in ESCCs from non-Iranian patients, were infrequent in the tumors we examined here. Elevated levels of cyclooxygenase-2 and inducible nitric oxide synthase were observed in 74 and 91%, respectively, of tumors from Tehran as determined by immunohistochemistry, and high COX-2 expression correlated significantly with the presence of a p53 mutation in the tumor. Mediators of the inflammatory response in esophageal mucosa, perhaps in conjunction with specific dietary or cultural practices in Iran, may contribute importantly to the p53 mutation load in Iranian ESCC patients.

Regional expression of sulfatides in rat kidney: immunohistochemical staining by use of monospecific polyclonal antibodies.

Sulfatides are quantitatively prominent glycosphingolipids of rat kidney. In order to gain insight into their possible physiological significance in this organ, and their possible role in Heymann's nephritis, the main sulfatide components were localized immunohistochemically. The antibodies used recognized the sulfatides Sgal1, Stri1, Stri2, and Stet2a. Stri1 epitopes were expressed in the brush border of proximal tubuli, whereas Stri2-specific immuno staining was observed in cortical and medullar collecting ducts. Both Stri1 and Stri2 were also expressed by interstitial cells of the inner medulla. Stet2a was visualized in epithelia of the distal tubules of Henle's loop and the juxtaglomerular apparatus, including the macula densa. The mAb Sulph-I, that recognizes the SO3(-)-3Galbeta

Influence of buprenorphine on acute experimental pancreatitis.

Buprenorphine (15 micrograms/kg b.wt. per hour) distinctly reduced pain sensitivity in acute 3% sodium-taurocholate pancreatitis in male Wistar rats without interfering with the course of the disease. This was seen by assessment of enzyme elevation in serum and ascites and by histological evaluation of the pancreas. Buprenorphine is therefore recommended for animal experiments to study the effect of therapeutic principles in acute pancreatitis.

Intrarenal arteries in rats with early two-kidney, one clip hypertension.

Structural arterial adaptation and decompensation were studied in the contralateral untouched kidneys of two-kidney, one clip hypertensive rats 1 to 64 days after constricting one renal artery. Focal necroses of intrarenal arteries were observed as early as 24 hours after starting the experiment. The necroses reached their maximum on Day 8 and thereafter decreased significantly in spite of still increasing blood pressure values. After 8 days the media thickness of the interlobular arteries was significantly increased by more than 30% and remained so until the end of the experiment. Blood pressure levels as measured by tail plethysmography were nearly normal within the first 4 days. The continuous 24-hour blood pressure recording in the conscious rats, however, showed shortlasting intermittent hypertensive spikes as early as 6 hours after renal artery constriction. In spite of these acute hypertensive peaks, which frequently exceeded 200 mm Hg, intimal lesions, potentially leading to malignant nephrosclerosis, began to appear after only 2 weeks. Thus, the development of nonobliterating, acute focal necroses of intrarenal arteries in the earliest stage of two-kidney, one clip hypertension may be explained by intermittent hypertensive episodes accompanied by a segmental overstretching of the nonadapted vascular bed. On the other hand, the occurrence of obliterating malignant nephrosclerosis in the presence of severe hypertension may also depend on the previously changed composition of the vessel walls.

Adaptation and decompensation of intrarenal small arteries in experimental hypertension.

In the presence of hypertension, the arterial and arteriolar vessel walls may undergo adaptive, destructive, and reparative changes. These different types of hypertensive alterations were studied simultaneously in the intrarenal vascular bed of two-kidney, one-clip hypertensive rats. After constriction of one renal artery, focal medial necrosis of the interlobular arteries developed in the untouched kidneys after the first 24 h. These earliest signs of vascular decompensation could be explained by short-lasting hypertensive episodes that were only detectable by continuous blood pressure recording in conscious animals. Two weeks after the experiment was started, owing to a widening of the media, a substantial increase in the wall-to-lumen ratio was observed in the interlobular arteries. At the same time, the frequency of focal medial necrosis began to fall significantly. Therefore we concluded that the structural vascular adaptation might be responsible for the disappearance of focal medial necrosis in spite of still rising blood pressure values. This assumption was confirmed by an additional experiment in previously chronically two-kidney, one-clip hypertensive rats: 24 h after removing the renal artery clip, a short, severely hypertensive period, induced by infusions of angiotensin II, caused hypertensive vascular lesions almost exclusively in the primarily clipped kidneys with a nonadapted vascular bed. Early intimal changes, which are known to lead to malignant nephrosclerosis, were not only absent in the beginning of two-kidney, one-clip hypertension, but also did not occur during the angiotensin-induced accelerated hypertension. Thus, even extremely high blood-pressure values per se may not be enough to initiate this crucial renal vascular disease.