Prevention and treatment of diabetic nephropathy in older patients

Renal disease in older diabetic patients is costly in terms of morbidity, mortality and expenditure. Therefore, prevention and treatment of diabetic nephropathy has become a prominent goal in the treatment of patients with diabetes mellitus. Preventive treatment should begin no later than at the stage of microalbuminuria, and regular screening for microalbuminuria is recommended for all patients with diabetes, irrespective of age. Improved metabolic control has been demonstrated to lower urinary albumin excretion. Target glycosylated haemoglobin levels should be below 7%, or 1% above the upper limit of normal of non-diabetic subjects. The use of an intensified treatment regimen is recommended. Insulin therapy has no adverse effects on renal indexes. To preserve renal function in older diabetic patients, blood pressure should be kept at or below 130/80 mm Hg. Treatment with ACE inhibitors or angiotensin II receptor antagonists (angiotensin II receptor blockers; ARBs) is superior to other pharmacological therapy, and should be initiated as first-line treatment. Most of the calcium channel antagonists have been found to increase or to have no effect on microalbuminuria despite blood pressure reduction. Moreover, there is substantial controversy as to whether they may be associated with increased cardiovascular morbidity. Non-dihydropyridine derivatives and calcium channel antagonists, such as nitrendipine, may be nephroprotective and have favourable effects on patients outcomes. A renoprotective action of diuretics may be confined to indapamide. Although beta-adrenoreceptor blockers are effective antihypertensive agents, they may not adequately preserve kidney function in older diabetic patients. However, as add-on treatment to ACE inhibitors or ARBs, they are particularly beneficial in nephropathic patients at risk of cardiovascular disease or with arrhythmias, in whom they may prove life-saving.     

A novel CACNA1F mutation in a french family with the incomplete type of X-linked congenital stationary night blindness

PURPOSE: To describe a French family with the incomplete type of X-linked congenital stationary night blindness (CSNB2) associated with a novel mutation in the retina-specific calcium channel alpha(1) subunit gene (CACNA1F). DESIGN: Interventional case report. METHODS: Two family members with a history of nonprogressive night blindness and subnormal visual acuity were clinically examined and the genotype determined by molecular genetic analysis. RESULT: Both patients had clinical manifestations characteristic of CSNB2. Electrophysiologically, we found a predominant reduction of the ERG B-wave in the maximal response. Both rod and cone function were subnormal, with the latter tending to be more attenuated. We identified a C deletion at nucleotide position 4548, resulting in a frameshift with a predicted premature termination at codon 1524. CONCLUSIONS: The clinical and genetic study of a novel mutation in the CACNA1F gene adds further support to the contention that CSNB2 represents a genetically distinct retinal disorder of a calcium channel.     

In vitro antiplasmodial evaluation of medicinal plants from Zimbabwe

In this study the in vitro antiplasmodial activities of extracts from Cussonia spicata (Araliaceae), Artemisia afra, Vernonia colorata, V. natalensis (Asteraceae), Parinari curatellifolia (Chrysobalanaceae), Clutia hirsuta, Flueggea virosa, (Euphorbiaceae), Adenia gummifera (Passifloraceae) and Hymenodictyon floribundum, (Rubiaceae) were evaluated. The lipophilic extracts from the aerial parts of Artemisia afra and Vernonia colorata proved to be the most active against the chloroquine-sensitive strain PoW and against the chloroquine-resistant clone Dd2 of Plasmodium falciparum. Bioassay-guided fractionation of the extract of A. afra yielded seven flavonoids, from which acacetin, genkwanin and 7-methoxyacacetin showed in vitro activity; the IC(50) values ranged from 4.3 microgram/mL to 12.6 microgram/mL. In addition, several sesquiterpene lactones could be obtained from the most active fractions. Whereas eudesmaafraglaucolide proved to be inactive, the guaianolides 1-desoxy-1alpha-peroxy-rupicolin A-8-O-acetate, 1alpha,4alpha-dihydroxybishopsolicepolide and rupicolin A-8-O-acetate revealed in vitro antiplasmodial activity. Evaluation of V. colorata gained four sesquiterpenes 11beta,13-dihydrovernodalin, vernodalol, 11beta,13-dihydrovernolide and 11beta,13,17,18-tetrahydrovernolide, from which the first two constituents exhibited the strongest antiplasmodial activity (IC(50) values: 1.1-4.8 microgram/mL).     

Functional regions of the presynaptic cytomatrix protein bassoon: significance for synaptic targeting and cytomatrix anchoring

Exocytosis of neurotransmitter from synaptic vesicles is restricted to specialized sites of the presynaptic plasma membrane called active zones. A complex cytomatrix of proteins exclusively assembled at active zones, the CAZ, is thought to form a molecular scaffold that organizes neurotransmitter release sites. Here, we have analyzed synaptic targeting and cytomatrix association of Bassoon, a major scaffolding protein of the CAZ. By combining immunocytochemistry and transfection of cultured hippocampal neurons, we show that the central portion of Bassoon is crucially involved in synaptic targeting and CAZ association. An N-terminal region harbors a distinct capacity for N-myristoylation-dependent targeting to synaptic vesicle clusters, but is not incorporated into the CAZ. Our data provide the first experimental evidence for the existence of distinct functional regions in Bassoon and suggest that a centrally located CAZ targeting function may be complemented by an N-terminal capacity for targeting to membrane-bounded synaptic organelles.     

Kainate-induced epileptic seizures induce a recruitment of caldendrin to the postsynaptic density in rat brain

Caldendrin defines a novel family of neuronal calcium-sensor proteins, the C-terminal moiety of which displays high similarity to calmodulin. We now report that the protein is recruited to the postsynaptic density (PSD) of cortical and hippocampal neurons in response to kainate-induced epileptic seizures, an animal model of human temporal lobe epilepsy. The translocation of caldendrin to the PSD did not occur in kainate-treated rats that did not develop seizures. The enhanced PSD levels of caldendrin are not due to increased protein synthesis and most likely reflect a recruitment from the soluble caldendrin protein pool. These findings suggest that the transduction of dendritic Ca2+-signals via caldendrin is altered by epileptic seizures and that caldendrin might be involved in the pathophysiology of temporal lobe epilepsy.     

Stimulation of plasminogen activation by recombinant cellular prion protein is conserved in the NH2-terminal fragment PrP23-110

The cellular prion protein (PrP(c)), tissue-type plasminogen activator (t-PA) and plasminogen are expressed in synaptic membranes in vivo. In the central nervous system the fibrinolytic system is associated with excitotoxin-mediated neurotoxicity and Alzheimer's disease. Recently binding of the disease associated isoform of the prion protein (PrP(Sc)) to plasminogen and stimulation of t-PA activity have been reported. In this study the interaction of PrP(c) and plasminogen was investigated using chromogenic assays in vitro. We found that plasmin is able to cleave recombinant PrP(c) at lysine residue 110 generating an NH(2)-terminal truncated molecule that has previously been described as a major product of PrP(c) metabolism. We further characterized the proteolytic fragments with respect to their ability to stimulate plasminogen activation in vitro. Our results show that the NH(2)-terminal part of PrP(c) spanning amino acids 23-110 (PrP23-110) together with low molecular weight heparin stimulates t-PA mediated plasminogen activation in vitro. The apparent rate constant was increased 57 fold in the presence of 800 nM PrP23-110. Furthermore, we compared the stimulation of t-PA activity by PrP(c) and beta-amyloid peptide (1-42). While the activity of the beta-amyloid was independent of low molecular weight heparin, PrP23-110 was approximately 4- and 37 fold more active than beta-amyloid in the absence or presence of low molecular weight heparin. In summary, plasmin cleaves PrP(c) in vitro and the liberated NH(2)-terminal fragment accelerates plasminogen activation. Cleavage of PrP c has previously been reported. Thus cleavage of PrP(c) enhancing plasminogen activation at the cell surface could constitute a regulatory mechanism of pericellular proteolysis.     

An outbreak of viral gastroenteritis in a mother-and-child health clinic

An outbreak of diarrhoeal disease in a modern mother-and-child health clinic prompted the health authorities to initiate a retrospective cohort study in order to assess the scope of the outbreak and to identify possible risk factors. The management of the clinic had been rather concerned because four similar outbreaks had occurred during the last two years. A total of 151 guests, i.e. mothers with their children, who had arrived some days before the peak of the outbreak for a three-week-stay and another 15 guests who had arrived earlier and had extended their stay were enrolled in the study which mainly focused on the possible role of treatment measures as risk factors. In addition, a total of 49 staff members were requested to provide information about symptoms, working area and attendance at work. Relevant data were available from 164 of 166 guests and 47 of 49 staff members (response rates 98.8% and 96.0%, respectively). The attack rate among guests was 44.0% (adults 27.0%, children 54.0%) and among staff 23.4%. The mean age of affected children (3.5 years) was significantly lower than that of those not affected (6.3 years). The main symptoms were diarrhoea and vomiting. The sudden start of the outbreak suggested a single source of infection which, however, remained unknown. Person-to-person transmission was supposed to be the cause of the following spread. No association between distinct treatment measures and the disease was proven by the cohort study. Norwalk-like viruses as well as astroviruses were detected by polymerase chain reaction in specimens taken from seven patients. No other enteropathogenic agents were found. Regarding the special conditions in a mother-and-child health clinic where social contacts among guests are much more frequent and intensive than among patients in a "normal" hospital, measures to prevent the spread of gastrointestinal infections should concentrate on early recognition and isolation of symptomatic individuals. Guests and staff members should be instructed to keep to the rules of personal hygiene, especially handwashing. If disinfection is required, it should be virucidal.     

Inhibition of adenovirus DNA polymerase by modified nucleoside triphosphate analogs correlate with their antiviral effects on cellular level

Adenovirus (Ad) infection results in significant morbidity and mortality in both immunocompetent and immunosuppressed hosts. There is currently no licensed chemotherapy effective in dealing with this virus infection. In this study the anti-adenoviral activity of a group of modified nucleoside analogs was investigated. The most efficient 3-fluorosubstituted nucleoside triphosphate inhibitors of Ad DNA polymerase were 3′-fluorothymidine triphosphate (IC₅₀ 0.63 μM), 2′,3′-dideoxy-3′-fluoroguanosine triphosphate (IC₅₀ 0.71 μM) and 2′,3′-dideoxy-3′-fluorouridine triphosphate (IC₅₀ 2.96 μM). The most efficient 2′,3′-dideoxynucleoside triphosphates were 2′,3′-dideoxycytidine triphosphate (ddCTP; IC₅₀ 1.0 μM), 2′,3′-dideoxyadenosine triphosphate (IC₅₀ 1.6 μM) and 2′,3′-dideoxythymidine triphosphate (IC₅₀ 1.82 μM). Kinetic studies indicate competitive inhibition of adenovirus DNA polymerase by ddCTP. These data confirm results previously obtained at the cellular level using a focus reduction assay involving Ad2-infected FL cells. Whereas the D-enantiomers 3′-fluorothymidine and 2′,3′-dideoxycytidine are potent inhibitors of adenoviral replication, the corresponding L-enantiomers exhibited no inhibitory activity. Received: 5 April 2000     

Clozapine-associated elevation of plasma cholinesterase

Objective The goal of this study was to identify adverse effects of the atypical neuroleptic clozapine on liver function and lipid metabolism. Methods Data which included serum levels of clozapine and its hepatic metabolite N-desmethyl clozapine were collected from medical records of patients treated with clozapine and controls. Results We identified a clozapine-associated marked elevation of plasma cholinesterase (ChE) with unchanged levels of AST, ALT or g-GT. ChE was correlated to the serum level of clozapine and even closer to N-desmethyl clozapine. For the total patient group we observed significant correlations of ChE with the body-mass index and body weight. However, clozapine-treated patients and controls did not differ with regard to body-mass index, triglycerides, and cholesterol. Conclusion We report for the first time a clozapine-associated and dose-dependent elevation of plasma ChE, which may be related to clozapine-associated effects on hepatic lipid metabolism or ChE enzyme induction. Received: 14 Mai 2001 / Accepted: 24 September 2001