A placebo-controlled trial of gabapentin for painful HIV-associated sensory neuropathies.

BACKGROUND: Painful HIV-associated sensory neuropathies (HIV-SN) are a common complication of HIV infection. The pathogenesis is unknown and the treatment very limited. Gabapentin (GBP) is effective in painful diabetic neuropathy and postherpetic neuralgia and its effectiveness on painful HIV-SN has been reported anecdotally. DESIGN: Multicenter, prospective, randomised, double-blind, placebo-controlled study. METHODS: Patients were followed for a 1-week screening, a 4-week double-blind and a 2-week open treatment phase. GBP was initiated at 400 mg/d, titrated over 2 weeks to 1200 mg/d, and then either maintained at this level or-if not beneficial-titrated to 2400 mg/d. After 4 weeks the medication was unblinded and the patient had the choice to begin, to maintain or to increase GBP to 3600 mg/d. The primary outcome measure was an improvement in median pain on the Visual Analogue Scale (VAS) from the screening week compared to the 4(th) treatment week. A secondary efficacy measure was the median sleep score (VAS). RESULTS: 15 patients received GBP and 11 placebo. In each group one patient dropped out during the doubleblind phase. Median pain (GBP 5.1; placebo 4.7) and sleep score (GBP 4.5; placebo 5.6) did not differ between both groups at baseline. In the GBP-group there was a significant decrease of the pain to 2.85 (-44.1 %) as well as of the sleep VAS to 2.3 (-48.9 %). No significant decrease in the pain (median VAS=3.3, -29.8 %) as well as in the sleep score (median VAS=4.95, -11.6 %) was observed in the placebo-group. GBP was generally well tolerated. The most frequent side effect was somnolence reported in 80% of GBP-treated patients. CONCLUSIONS: GBP was more effective than placebo in reducing pain and sleep interference in patients with HIV-SN.

Apoptosis-inducing factor mediates microglial and neuronal apoptosis caused by pneumococcus.

Streptococcus pneumoniae is the major cause of bacterial meningitis and it damages the hippocampus by inducing neuronal apoptosis. The blocking of caspases provides only partial protection in experimental meningitis, which suggests that there is an additional apoptotic pathway. A trigger of this pathway is the bacterium itself, as exposure of microglia or neurons to live pneumococci induces rapid apoptosis. In this study, apoptosis was not associated with the activation of caspases-1-10 and was not inhibited by z-VAD-fmk, a broad-spectrum caspase inhibitor. Rather, apoptosis was attributed to damage to mitochondria, which was followed by the release of apoptosis-inducing factor (AIF) from the mitochondria, large-scale DNA fragmentation, and hypodiploidy. Furthermore, intracytoplasmatic microinjection of AIF-specific antiserum markedly impaired pneumococcus-induced apoptosis. These findings indicate that AIF may play a central role in brain cell apoptosis and bacterial pathogenesis.

Group B streptococcal beta-hemolysin induces nitric oxide production in murine macrophages.

Group B streptococcus (GBS) is the leading cause of sepsis in neonates. Nitric oxide (NO) release plays a role in the hypotension that characterizes septic shock. To examine the role of the GBS beta-hemolysin in NO production, the murine macrophage line RAW 264. 7 was exposed to a wild-type (WT) GBS isolate and to hyperhemolytic (HH) and nonhemolytic (NH) transposon mutants derived from that isolate. After activation of macrophages by the WT strain, the HH mutant, or cell-free extracts of beta-hemolysin, nitrite release into the supernatant increased >10-fold and inducible NO synthase (iNOS) levels in cell lysates increased up to 10-fold compared with treatment with the NH mutant or extracts from that mutant. Hemolysin-induced NO production was dependent on protein tyrosine kinases and NF-kappaB, but not on extracellular signal-related kinase-1/2-mitogen-activated kinases or protein kinase A. These results indicate that GBS beta-hemolysin induces murine macrophage iNOS via intracellular pathways similar to those that mediate lipopolysaccharide-induced iNOS activation.

Extracellular targeting of choline-binding proteins in Streptococcus pneumoniae by a zinc metalloprotease.

A genetic-based search for surface proteins of Streptococcus pneumoniae involved in adhesion identified a putative zinc metalloprotease (ZmpB). ZmpB shared high amino acid sequence similarities with IgA1 proteases of Gram-positive bacteria, but ZmpB had neither IgA1 nor IgA2 protease activity. Analysis of a family of surface-expressed proteins, the choline-binding proteins (Cbp's), in a zmpB-deficient mutant demonstrated a global loss of surface expression of CbpA, CbpE, CbpF and CbpJ. CbpA was detected within the cytoplasm. The zmpB-deficient mutant also failed to lyse with penicillin, a sign of lack of function of the Cbp LytA. Immunodetection studies revealed that the autolysin (LytA), normally located on the cell wall, was trapped in the cytoplasm colocalized with DNA and the transformation protein CinA. Trafficking of CinA and RecA to the cell membrane during genetic competence was also not observed in the zmpB-deficient mutant. These results suggest a protease dependent regulatory mechanism governing the translocation of CinA and the Cbp's LytA and CbpA of S. pneumoniae.

Signal transduction by a death signal peptide: uncovering the mechanism of bacterial killing by penicillin.

The binding of bactericidal antibiotics like penicillins, cephalosporins, and glycopeptides to their bacterial targets stops bacterial growth but does not directly cause cell death. A second process arising from the bacteria itself is necessary to trigger endogenous suicidal enzymes that dissolve the cell wall during autolysis. The signal and the trigger pathway for this event are completely unknown. Using S. pneumoniae as a model, we demonstrate that signal transduction via the two-component system VncR/S triggers multiple death pathways. We show that the signal sensed by VncR/S is a secreted peptide, Pep27, that initiates the cell death program. These data depict a novel model for the control of bacterial cell death.

Pneumolysin, a protein toxin of Streptococcus pneumoniae, induces nitric oxide production from macrophages.

Nitric oxide (NO) production by inducible NO synthase (iNOS) during inflammation is an essential element of antimicrobial immunity but can also contribute to host-induced tissue damage. Under conditions of bacterial sepsis, large amounts of NO are produced, causing hypotension, a critical pathological feature of septic shock. In sepsis caused by gram-positive organisms, the bacterial factors contributing to host NO production are poorly characterized. We show that a soluble toxin of Streptococcus pneumoniae, pneumolysin (Pln), is a key component initiating NO production from macrophages. In contrast to wild-type bacteria, a mutant of S. pneumoniae lacking Pln failed to elicit NO production from murine macrophages. Purified recombinant Pln induced NO production at low concentrations and independently of exogenous gamma interferon (IFN-gamma) priming of RAW 264.7 macrophages. However, IFN-gamma was essential for Pln-induced NO production, since primary macrophages from mice lacking the IFN-gamma receptor or interferon regulatory factor 1, a transcription factor essential for iNOS expression, failed to produce NO when stimulated with Pln. In addition, Pln acts as an agonist of tumor necrosis factor alpha and interleukin 6 production in macrophages. The properties of Pln, previously identified as a pore-forming hemolysin, also include a role as a general inflammatory agonist.

Neuroprotection by a caspase inhibitor in acute bacterial meningitis.

Half of the survivors of bacterial meningitis experience motor deficits, seizures, hearing loss or cognitive impairment, despite adequate bacterial killing by antibiotics. We demonstrate that the broad-spectrum caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl-ketone (z-VAD-fmk) prevented hippocampal neuronal cell death and white blood cell influx into the cerebrospinal fluid compartment in experimental pneumococcal meningitis. Hippocampal neuronal death was due to apoptosis derived from the inflammatory response in the cerebrospinal fluid. Apoptosis was induced in vitro in human neurons by inflamed cerebrospinal fluid and was blocked by z-VAD-fmk. As apoptosis drives neuronal loss in pneumococcal meningitis, caspase inhibitors might provide a new therapeutic option directed specifically at reducing brain damage.

[Delirium during oral therapy of herpes zoster with acyclovir. Case report and brief review of central nervous system side-effects of acyclovir]. / Delir während der oralen Therapie eines Herpes zoster mit Aciclovir. Kasuistik und Kurzübersicht über zentralnervöse Nebenwirkungen von Aciclovir.

In differential diagnosis of a delir also adverse effects of medicaments have to be taken into account beside other causes. We report a case of an agitated delir with nocturnal disturbance of consciousness, confusion, restlessness and sleeplessness. This delir existed exclusively during the therapy of a cutaneous herpes zoster with zovirax-pills which can only be explained by a causal connection--after exclusion of other causes. As a so far undescribed predisposition for neurotoxicity of oral therapy with acyclovir signs of vascular encephalopathy were found in the patient's cranial magnetic resonance imaging. The central nervous side effects of acyclovir were summarized shortly.

Hepatitis caused by antidepressive therapy with maprotiline and opipramol.

There are few published reports of antidepressive therapy induced hepatotoxicity. In most cases antidepressants cause only slight elevation of liver enzymes without clinical relevance. However, our patient with recidivation of unipolar depressive disorder developed severe laboratory abnormalities and clinical symptoms during therapy with maprotiline (Ludiomil) and opipramol (Insidon). To our knowledge, this is the first case report of bioptically proven severe acute hepatitis caused by these antidepressants. After their withdrawal, the patient's fatigue symptoms, scleric jaundice, and marked increase of liver enzymes completely disappeared. Hepatic side effects should be considered during antidepressive therapy with maprotiline and opipramol especially when additional clinical symptoms emerge.

Penicillin tolerance genes of Streptococcus pneumoniae: the ABC-type manganese permease complex Psa.

Downregulation of the major autolysin in Streptococcus pneumoniae leads to penicillin tolerance, a feature that is characterized by the ability to survive but not grow in the presence of antibiotic. Screening a library of mutants in pneumococcal surface proteins for the ability to survive 10x minimum inhibitory concentration (MIC) of penicillin revealed over 10 candidate tolerance genes. One such mutant contained an insertion in the known gene psaA, which is part of the psa locus. This locus encodes an ABC-type Mn permease complex. Sequence analysis of adjacent DNA extended the known genetic organization of the locus to include two new open reading frames (ORFs), psaB, which encodes an ATP-binding protein, and psaC, which encodes a hydrophobic transmembrane protein. Mutagenesis of psaB, psaC, psaA and downstream psaD resulted in penicillin tolerance. Defective adhesion and reduced transformation efficiency, as reported previously for a psaA- mutant, were phenotypes shared by psaB-, psaC- and psaD- knockout mutants. Western blot analysis demonstrated that the set of mutants expressed RecA, but none of them showed translation of the autolysin gene, which is located downstream of recA. The addition of manganese (Mn) failed to correct the abnormal physiology. These results suggest that this ABC-type Mn permease complex has a pleiotropic effect on pneumococcal physiology including adherence and autolysis. These are the first genes suggested as being involved in triggering autolysin. The results raise the possibility that loss of function of PsaA, by vaccine-induced antibody for instance, may promote penicillin tolerance.

Spatiotemporal relationship of apoptotic cell death to lymphomonocytic infiltration in photochemically induced focal ischemia of the rat cerebral cortex.

In this study we examined the time course of apoptotic cell death after photochemically induced focal ischemia of the rat cerebral cortex. For unequivocal differentiation between apoptosis and necrosis two criteria of programmed cell death were used: terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) and morphological evidence of fragmentation and marginalization of nuclei. After photothrombosis, many TUNEL-positive cells were found within the infarct region from 12 h to 3 days. By day 6 they were preferentially located in the boundary zone of the infarct, and by day 14 they had disappeared. A high proportion of TUNEL-positive cells displayed fragmentation or marginalization of their nuclei, indicating apoptosis. Neurons, but not T cells and macrophages, were apoptotic. Inflammatory infiltrates were in close contact to apoptotic neurons throughout the infarct areas at day 1 and in the boundary zone between days 2 and 6 after photothrombosis. In summary, our study shows that neuronal apoptosis after cerebral ischemia is a prolonged process to which leukocyte-derived cytokines may contribute. In contrast to autoimmune diseases of the nervous system, termination of the local inflammatory response after cerebral ischemia does not involve apoptosis.

Morphological indications for considerable diffuse reabsorption of cerebrospinal fluid in spinal meninges particularly in the areas of meningeal funnels. An electronmicroscopical study including tracing experiments in rats.

Transmission and scanning electron microscopical observations in the rat indicate a considerable capacity of the spinal meninges to reabsorb cerebrospinal fluid. The density of blood vessels and lymphatics in the duramater is extremely high, particularly in the areas of meningeal funnels and spinal nerve root sleeves. Arterioles with closely related unmyelinated nerve fibres, many fenestrated capillaries and venules predetermine these areas as sites where absorption processes could take place. At certain sites of the meningeal angle region, the arachnoid membrane, mostly multilayered, is reduced to only three or four layers. Intercellular discontinuities and cytoplasmic fenestrations occurring in the arachnoid lining cell layer result in direct communications between the subarachnoid space and cisterns of the arachnoid "reticular layer". These cisterns are partly fluid-filled, partly occupied by a net of collagen fibre bundles. Some cisterns harbour macrophages that often project filiform processes through the lining cell layer into the subarachnoid space, contacting cerebrospinal fluid. Desmosomes and gap junctions are present in all layers of the arachnoid. However, tight junctions and the continuous electrondense intercellular gap, known to occur normally within the "arachnoid barrier layer", were not seen in many sites of the meningeal angle region. Numerous arachnoid cells display a high degree of vesiculation. Cationized ferritin, introduced in vivo into the rat subarachnoid space, passes inter- and intracellularly from the cerebrospinal fluid compartment through the arachnoid membrane, reaching dural blood vessels and lymphatics. Tracer could be visualized both in the cytoplasm of the endothelium and on the luminal surface of the cells. Tracer also passed through pial cell layers into pial vessels, through leptomeningeal sheaths into vessels crossing the subarachnoid space, into the connective tissue compartment and into vessels of spinal dorsal root ganglia. In the angle region, a particularly large number of macrophages can be found on the surface of leptomeninges, within the arachnoid reticular layers, and in close relation to dural and epidural capillaries, venules and lymphatics. Their possible role in the process of cerebrospinal fluid reabsorption is discussed.

Morphology and distribution of ecto-5'-nucleotidase-positive cells in the rat choroid plexus.

The aim of this report was to find out whether adenosine can be produced locally in the choroid plexus of rats. Therefore we investigated the distribution of the enzyme ecto-5'-nucleotidase which hydrolyzes extracellular adenosine monophosphate to adenosine and phosphate. Enzyme activity histochemistry and immunohistochemistry demonstrated that ecto-5'-nucleotidase is present in the stroma but not in the epithelium. The positive cells in the stroma were identified as fibroblasts by their localization and by their shape. Double-labelling immunohistochemistry actually showed that ecto-5'-nucleotidase was absent from MHC class II-positive cells and from vessel walls. These data indicate that adenosine may be produced in the choroid plexus, and specifically in the interstitium. From there, adenosine would have direct access to nerves, immune cells, the epithelium and microvessels. Because adenosine has been reported to modulate blood supply and the rate of production of cerebrospinal fluid, a local control mechanism involving adenosine might operate in the choroid plexus in a similar way to that described in other tissues. Effects of adenosine on nerves and immune cells are discussed. The exclusive presence of ecto-5'-nucleotidase in the fibroblasts that are in contact with choroid plexus epithelium suggests that the expression of the enzyme is controlled by factors produced by epithelial cells, for instance by extracellular nucleotides.

Assessment of body composition with use of dual-energy x-ray absorptiometry: evaluation and comparison with other methods.

Dual-energy x-ray absorptiometry (DEXA) is a relatively new method of assessing body composition in humans. In the current study, DEXA was analyzed for accuracy and precision by using both anthropomorphic phantoms and a combination of body composition techniques in humans. Satisfactory precision for measurement of total body fat, fat-free mass, and total body bone mineral could be demonstrated in vivo and in vitro. Predictions of lean body mass in humans on the basis of DEXA, total body water, and total body potassium were significantly different. The results of multiple regression analysis suggested that a component of total body water was related to body potassium, and another component was predicted by body fat. In addition, extracellular fluid volume, as measured by the bromide space technique, was significantly associated with both fat-free mass and fat mass as measured by DEXA. These findings have implications for the interpretation of body composition data in humans.

Cellular components of the immune barrier in the spinal meninges and dorsal root ganglia of the normal rat: immunohistochemical (MHC class II) and electron-microscopic observations.

This report deals with the distribution, morphology and specific topical relationships of bone-marrow-derived cells (free cells) in the spinal meninges and dorsal root ganglia of the normal rat. The morphology of these cells has been studied by transmission and scanning electron microscopy. Cells expressing the major histocompatibility complex (MHC) class II gene product have been recognized by immunofluorescence. At the level of the transmission electron microscope, free cells are found in all layers of the meninges. Many of them display characteristic ultrastructural features of macrophages, whereas others show a highly vacuolated cytoplasm and are endowed with many processes. These elements lack a conspicuous lysosomal system and might represent dendritic cells. Scanning electron microscopy has revealed that free cells contact the cerebrospinal fluid via abundant cytoplasmic processes that cross the cell layers of the pia mater and of the arachnoid. Cells expressing the MHC class II antigen are also found in all layers of the meninges. They are particularly abundant in the layers immediately adjacent to the subarachnoid space, in the neighbourhood of dural vessels, along the spinal roots and in the dural funnels. In addition to the meninges, strong immunoreactivity for MHC class II antigen is observed in the dorsal root ganglia. The ultrastructural and immunohistochemical findings of this study suggest the existence of a well-developed system of immunological surveillance of the subarachnoid space and of the dorsal root ganglia.

Measurement of body potassium with a whole-body counter: relationship between lean body mass and resting energy expenditure.

We conducted studies to determine whether the Mayo whole-body counter could be used to measure body potassium, and thus lean body mass (LBM), and whether moderate obesity alters resting energy expenditure when corrected for LBM. Twenty-four nonobese and 18 moderately obese adults underwent body potassium (40K) counting, as well as tritiated water space measurement and indirect calorimetry. LBM values predicted from 40K counting and tritiated water space measurements were highly correlated (P = 0.001; r = 0.88). Resting energy expenditure was closely related to LBM (P less than 0.0001; r = 0.78): kcal/day = 622 kcal + (LBM.20.0 kcal/kg LBM). In this relationship, the obese subjects did not differ from nonobese subjects. In summary, the Mayo whole-body counter can accurately measure LBM, and moderate obesity has no detectable effect on corrected resting energy expenditure.

[Determination of serum digoxin. A comparison between RIA and EIA (author's transl)]. / Digoxinbestimmung im Serum. Vergleich zwischen Radio- und Enzymimmunoassay.

The results of two radioimmunoassays (RIA, precipitating technique), of a homogenous (EMIT) and a heterogenous (ELISA) enzyme immunoassay (EIA) for ascertaining the amounts of digoxin showed a good correlation in precision and a reasonably satisfying correlation in the recovery. However, there was a clear discrepancy in the amounts of digoxin concentrate in the serum of patients. Only the RIA of Abbott and the EIA of Boehringer showed no significant differences. Particularly noticeable was the tendency towards lower values in the EMIT-technique as well as its liability to unspecific serum changes (lipaemia etc.), which often made the detection of digoxin impossible. The routine use of this technique appears problematic. The need for establishing one's own laboratory and test-specific therapeutical range is pointed out.

[Pre-stained slides for differential blood counts (author's transl)]. / Farbbeschichtete Objektträger: eine einfache Färbemethode für das Differentialblutbild.

A new method for differential blood counts using pre-stained slides showed it to be suitable for routine use. To differentiate white blood cells the same experience was needed as for conventional stainings. Normal and abnormal blood pictures can be reliably distinguished. The particular advantage of the method is in the simple preparation of the smear and in avoiding the need for time-consuming staining.