Case fatality ratio and mortality rate trends of community-onset Staphylococcus aureus bacteraemia

Lethal outcomes can be expressed as a case fatality ratio (CFR) or as a mortality rate per 100 000 population per year (MR). Population surveillance for community-onset methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus bacteraemia was conducted in Canada, Australia, Sweden and Denmark to evaluate 30-day CFR and MR trends between 2000 and 2008. The CFR was 20.3% (MSSA 20.2%, MRSA 22.3%) and MR was 3.4 (MSSA 3.1, MRSA 0.3) per 100 000 per year. Although MSSA CFR was stable the MSSA MR increased; MRSA CFR decreased while its MR remained low during the study. Community-onset S. aureus bacteraemia, particularly MSSA, is associated with major disease burden. This study highlights complementary information provided by evaluating both CFR and MR.

The changing epidemiology of Staphylococcus aureus bloodstream infection: a multinational population-based surveillance study

Although the epidemiology of Staphylococcus aureus bloodstream infection (BSI) has been changing, international comparisons are lacking. We sought to determine the incidence of S. aureus BSI and assess trends over time and by region. Population-based surveillance was conducted nationally in Finland and regionally in Canberra, Australia, western Sweden, and three areas in each of Canada and Denmark during 2000-2008. Incidence rates were age-standardized and gender-standardized to the EU 27-country 2007 population. During 83 million person-years of surveillance, 18,430 episodes of S. aureus BSI were identified. The overall annual incidence rate for S. aureus BSI was 26.1 per 100,000 population, and those for methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) were 24.2 and 1.9 per 100,000, respectively. Although the overall incidence of community-onset MSSA BSI (15.0 per 100,000) was relatively similar across regions, the incidence rates of hospital-onset MSSA (9.2 per 100,000), community-onset MRSA (1.0 per 100,000) and hospital-onset MRSA (0.8 per 100,000) BSI varied substantially. Whereas the overall incidence of S. aureus BSI did not increase over the study period, there was an increase in the incidence of MRSA BSI. Major changes in the occurrence of community-onset and hospital-onset MSSA and MRSA BSI occurred, but these varied significantly among regions, even within the same country. Although major changes in the epidemiology of community-onset and hospital-onset MSSA and MRSA BSIs are occurring, this multinational population-based study did not find that the overall incidence of S. aureus BSI is increasing.

Cloning and expression of a novel human glutaredoxin (Grx2) with mitochondrial and nuclear isoforms

Glutaredoxin (Grx) is a glutathione-dependent hydrogen donor for ribonucleotide reductase. Today glutaredoxins are known as a multifunctional family of GSH-disulfide-oxidoreductases belonging to the thioredoxin fold superfamily. In contrast to Escherichia coli and yeast, a single human glutaredoxin is known. We have identified and cloned a novel 18-kDa human dithiol glutaredoxin, named glutaredoxin-2 (Grx2), which is 34% identical to the previously known cytosolic 12-kDa human Grx1. The human Grx2 sequence contains three characteristic regions of the glutaredoxin family: the dithiol/disulfide active site, CSYC, the GSH binding site, and a hydrophobic surface area. The human Grx2 gene, located at chromosome 1q31.2--31.3, consisted of five exons that were transcribed to a 0.9-kilobase human Grx2 mRNA ubiquitously expressed in several tissues. Two alternatively spliced Grx2 mRNA isoforms that differed in their 5' region were identified. These corresponded to alternative proteins with a common 125-residue C-terminal Grx domain but with different N-terminal extensions of 39 and 40 residues, respectively. The 125-residue Grx domain and the two full-length variants were expressed in E. coli and exhibited GSH-dependent hydroxyethyl disulfide and dehydroascorbate reducing activities. Western blot analysis of subcellular fractions from Jurkat cells with a specific anti-Grx2 antibody showed that human Grx2 was predominantly located in the nucleus but also present in the mitochondria. We further showed that one of the mRNA isoforms corresponding to Grx2a encoded a functional N-terminal mitochondrial translocation signal.

Thiols decrease cytokine levels and down-regulate the expression of CD30 on human allergen-specific T helper (Th) 0 and Th2 cells

The thiol antioxidant N-acetyl- L-cysteine (NAC), known as a precursor of glutathione (GSH), is used in AIDS treatment trials, as a chemoprotectant in cancer chemotherapy and in treatment of chronic bronchitis. In vitro, GSH and NAC are known to enhance T cell proliferation, production of IL-2 and up-regulation of the IL-2 receptor. The 120-kD CD30 surface antigen belongs to the tumour necrosis factor (TNF) receptor superfamily. It is expressed by activated T helper (Th) cells and its expression is sustained in Th2 cells. We have analysed the effect of GSH and NAC on the cytokine profile and CD30 expression on human allergen-specific T cell clones (TCC). TCC were stimulated with anti-CD3 antibodies in the presence of different concentrations of GSH and NAC. Both thiols caused a dose dependent down-regulation of IL-4, IL-5 and IFN-gamma levels in Th0 and Th2 clones, with the most pronounced decrease of IL-4. Furthermore, they down-regulated the surface expression of CD30, and the levels of soluble CD30 (sCD30) in the culture supernatants were decreased. In contrast, the surface expression of CD28 or CD40 ligand (CD40L) was not significantly changed after treatment with 20 m M NAC. These results indicate that GSH and NAC favour a Th1 response by a preferential down-regulation of IL-4. In addition, the expression of CD30 was down regulated by GSH and NAC, suggesting that CD30 expression is dependent on IL-4, or modified by NAC. In the likely event that CD30 and its soluble counterpart prove to contribute to the pathogenesis in Th2 related diseases such as allergy, NAC may be considered as a future therapeutic agent in the treatment of these diseases.

Isoform-specific exocytotic protein mRNA expression in hypothalamic magnocellular neurons: regulation after osmotic challenge

Exocytosis is regulated by proteins which interact to promote docking and fusion of secretory granules with the plasma membrane. We have used in situ hybridization to study the mRNA expression for vesicle-associated membrane protein (VAMP) isoforms VAMP-1 and VAMP-2, synaptosomal-associated protein of 25-kDa (SNAP-25) isoforms SNAP-25a and SNAP-25b, mammalian homologue of unc-18 (munc-18) and Hrs-2 in neurosecretory neurons of the magnocellular paraventricular (PVN) and supraoptic (SON) nuclei of normal and osmotically challenged animals. In PVN and SON neurons of normal animals, strong labeling was demonstrated for VAMP-2 and SNAP-25a mRNA, whereas VAMP-1 or SNAP-25b mRNA could not be detected. Salt-loading (2% NaCl as drinking water), an animal model which increases the expression and secretion of hormones from hypothalamic magnocellular neurons, resulted in significantly increased mRNA levels for VAMP-2 (36%, 28%), munc-18 (74%, 68%) and SNAP-25a (59%, 77%) in the PVN and SON, respectively. There was no significant increase in Hrs-2 mRNA levels in the PVN, whereas a significant increase (22%) was observed in the SON. In the posterior pituitary, immunohistochemistry showed a marked decrease in numbers and intensity of vasopressin-immunoreactive (-IR) nerve endings after salt-loading. There were no obvious changes in numbers or intensity of VAMP-2-, munc-18-, Hrs-2- or SNAP-25-IR fibers. Large varicosities containing VAMP-2- and Hrs-2 immunocreactivity were seen in salt-loaded animals. The results show isoform-specific mRNA expression in neurosecretory neurons and an increased mRNA expression of proteins participating in the molecular regulation of exocytosis during an experimental situation characterized by increased secretion.

Differential expression of SNAP-25a and SNAP-25b RNA transcripts in cranial nerve nuclei

Synaptosomal-associated protein of 25 kDa (SNAP-25) is involved in the molecular regulation of neurotransmitter release. SNAP-25 exists in two isoforms, SNAP-25a and SNAP-25b, which arise from alternate splicing and which are differentially expressed throughout the nervous system. In situ hybridization was used to examine the presence and subcellular localization of SNAP-25a and SNAP-25b RNA transcript expression in motor and parasympathetic nuclei associated with cranial nerves. SNAP-25a RNA transcripts were strongly expressed in the parasympathetic Edinger-Westphal nucleus and dorsal motor nucleus of the vagus nerve but weakly expressed in motor nuclei such as the oculomotor, trochlear, trigeminal, facial, ambiguus, hypoglossal and accessory nuclei and in motoneurons of mouse lumbar spinal cord. In contrast, SNAP-25b RNA transcripts were not detectable in the Edinger-Westphal nucleus and dorsal motor nucleus of the vagus nerve but were strongly expressed in the oculomotor, trochlear, trigeminal, facial, ambiguus, hypoglossal, and accessory nuclei and in the motoneurons of mouse lumbar spinal cord. In the parasympathetic cranial nerve nuclei, displaying high levels of SNAP-25a RNA transcripts, the labeling was cytoplasmic, whereas the labeling was nuclear in the cranial nerve motor nuclei, displaying lower levels of transcripts. In contrast, labeling of SNAP-25b RNA transcripts was cytoplasmic in cranial nerve motor nuclei and not detectable in parasympathetic cranial nerve nuclei. Possible explanations for the region-specific and differential subcellular localization of SNAP-25a and SNAP-25b RNA transcripts are discussed.

Cysteine string protein (CSP) is an insulin secretory granule-associated protein regulating beta-cell exocytosis

Cysteine string proteins (CSPs) are novel synaptic vesicle-associated protein components characterized by an N-terminal J-domain and a central palmitoylated string of cysteine residues. The cellular localization and functional role of CSP was studied in pancreatic endocrine cells. In situ hybridization and RT-PCR analysis demonstrated CSP mRNA expression in insulin-producing cells. CSP1 mRNA was present in pancreatic islets; both CSP1 and CSP2 mRNAs were seen in insulin-secreting cell lines. Punctate CSP-like immunoreactivity (CSP-LI) was demonstrated in most islets of Langerhans cells, acinar cells and nerve fibers of the rat pancreas. Ultrastructural analysis showed CSP-LI in close association with membranes of secretory granules of cells in the endo- and exocrine pancreas. Subcellular fractionation of insulinoma cells showed CSP1 (34/36 kDa) in granular fractions; the membrane and cytosol fractions contained predominantly CSP2 (27 kDa). The fractions also contained proteins of 72 and 70 kDa, presumably CSP dimers. CSP1 overexpression in INS-1 cells or intracellular administration of CSP antibodies into mouse ob/ob beta-cells did not affect voltage-dependent Ca2+-channel activity. Amperometric measurements showed a significant decrease in insulin exocytosis in individual INS-1 cells after CSP1 overexpression. We conclude that CSP is associated with insulin secretory granules and that CSP participates in the molecular regulation of insulin exocytosis by mechanisms not involving changes in the activity of voltage-gated Ca2+-channels.

Decreased mRNA levels for exocytotic proteins in the pituitary of aged rats

Several protein components that are involved in the molecular regulation of transmitter release have been identified in neuronal, neuroendocrine and endocrine tissues. The expression of VAMP-2 (vesicle-associated membrane protein), munc-18 (mammalian homologue of unc-18) and SNAP-25 (synaptosomal-associated protein of 25 kDa) mRNA was studied in the rat anterior and intermediate pituitary gland of adult (2 months) and old (24 months) rats using in situ hybridization. In the pituitary anterior lobe of aged rats, there was a significant decrease in VAMP-2 (33%), munc-18 (17%) and SNAP-25 (20%) mRNA as compared to adult rats. In the intermediate lobe, there was a significant decrease in VAMP-2 (48%) and SNAP-25 (32%) mRNA of aged rats, whereas munc-18 mRNA levels were not significantly changed. Pituitaries from aged rats showed an increase in size which was paralleled by a significant decrease in the number of cells per unit area in the intermediate lobe, whereas the number was unaltered in the anterior lobe. The results suggest a genuine decrease in mRNA for exocytotic protein mRNA in the anterior pituitary, but that part of the decrease in the expression of VAMP-2 and SNAP-25 mRNA in the intermediate lobe can be explained by a decreased number of cells per unit area. The decline in anterior pituitary hormone secretion reported in aged rats appears to be parallelled by a down-regulation in mRNA levels for several proteins involved in the molecular regulation of exocytosis.

Estrogen down-regulates mRNA encoding the exocytotic protein SNAP-25 in the rat pituitary gland

Exocytosis is dependent on specific proteins that are located at the secretory granule membrane, in the cytoplasm or at the plasma membrane. The mRNA expression of synaptosomal-associated protein of 25 kDa (SNAP-25) isoforms SNAP-25a and SNAP-25b, vesicle associated membrane protein (VAMP) 2, mammalian homologue of unc-18 (munc-18) and Hrs-2 was studied in the pituitary of ovariectomized rats after subcutaneous insertion of capsules containing estrogen or placebo using in situ hybridization. Estrogen treatment (0.25 mg estradiol) significantly decreased SNAP-25a (32%; 10%) and SNAP-25b (25%; 22%) mRNA levels in the anterior and intermediate lobes, respectively, whereas VAMP-2, munc-18 and Hrs-2 mRNA levels remained unchanged. The results suggest that estrogen selectively regulates SNAP-25 transcription in the pituitary gland, but leaves VAMP-2, munc-18 and Hrs-2 mRNA levels unaffected.

VAMP-1 and VAMP-2 gene expression in rat spinal motoneurones: differential regulation after neuronal injury

Vesicle-associated membrane protein (VAMP; synaptobrevin) is involved in the molecular regulation of transmitter release at the presynaptic plasma membrane. VAMP exists in two isoforms, VAMP-1 and VAMP-2, which are transcribed from two separate genes and differentially expressed in the nervous system. In situ hybridization was used to examine whether VAMP isoform mRNA expression may be altered by experimental manipulations. The effect of nerve injury on VAMP-1 and VAMP-2 mRNA levels in motoneurones of the rat lumbar spinal cord was compared with lesion-induced changes in the expression of choline acetyl transferase (ChAT) and alpha-calcitonin gene-related peptide (alpha-CGRP) mRNA. After unilateral sciatic nerve transection (axotomy), VAMP-1 mRNA expression decreased significantly in parallel with a downregulation of ChAT mRNA in axotomized motoneurones compared with the corresponding motoneurones on the contralateral unlesioned side. There was a rapid decrease in VAMP-1 and ChAT mRNA levels at 2 days after axotomy, and at 7 days there was a 65% decrease in VAMP-1 mRNA and a 48% decrease in ChAT mRNA. VAMP-1 mRNA levels continued to decrease at 14 and 21 days, while ChAT mRNA levels had returned to normal at this time. In contrast, VAMP-2 and alpha-CGRP mRNA levels were upregulated in axotomized motoneurones. A significant increase for both VAMP-2 and alpha-CGRP mRNA levels was present 2 days after axotomy, and a maximum was reached after 7 days for alpha-CGRP mRNA (163%) and after 14 days for VAMP-2 mRNA (587%). Immunohistochemical analysis did not reveal any detectable changes in VAMP-1- or VAMP-2-like immunoreactivity in the motoneurone cell soma after axotomy. In the proximal end of the transected sciatic nerve, there was an increase in VAMP-1- and VAMP-2-LI, which was most prominent at 2 days after lesion. The results show that, in axotomized spinal motoneurones, VAMP-1 mRNA is downregulated and VAMP-2 mRNA is upregulated, indicating differential regulation of the two separate VAMP genes and differential roles for the two VAMP isoforms in the regulation of exocytosis after nerve injury.

Exocytotic proteins in enterochromaffin-like (ECL) cells of the rat stomach

Proteins participating in vesicular docking and fusion have been identified in the nervous system. Such proteins appear to be important for the molecular regulation of exocytosis also in non-neuronal cells. The enterochromaffin-like (ECL) cells of the gastric acid-secreting (oxyntic) mucosa secrete histamine and chromogranin A-derived peptides, such as pancreastatin. Using immunohistochemistry, we have examined whether the ECL cells of the rat stomach, identified with antibodies to histidine decarboxylase (HDC, the histamine-forming enzyme), express the same exocytotic proteins as neurons. The ECL cells displayed immunoreactivity for synaptophysin, synaptotagmin III, vesicle-associated membrane protein-2 (VAMP-2), cysteine string protein (CSP), vesicular monoamine transporter-2 (VMAT-2), synaptosomal-associated protein of 25 kDa (SNAP-25), syntaxin, and Munc-18, but not for synaptotagmin I/II and VAMP-1. Synaptophysin and VMAT-2 could be detected not only in the ECL cells, but also in a population of HDC-negative cells. The demonstration of synaptotagmin III in only a limited number of ECL cells suggests the existence of a subpopulation of ECL cells. The results show that several exocytotic proteins, previously identified in neurons, are present in rat stomach ECL cells. Hence, proteins engaged in vesicular docking and in the fusion of granule/vesicle membrane with plasma membrane seem to exist in both neurons and endocrine cells.

Methodological aspects for in vitro characterization of receptor binding using 11C-labeled receptor ligands: a detailed study with the benzodiazepine receptor antagonist [11C]Ro 15-1788

As a complement to in vivo studies with positron emission tomography (PET), it is desirable to perform in vitro characterization of newly developed 11C tracers. In this report we describe the technique for determination of receptor-ligand kinetics utilizing ligands labeled with the short-lived radionuclide 11C. The limitations and advantages are discussed. The benzodiazepine antagonist [11C]Ro 15-1788 was used as a model substance, and the use of storage phosphor plates for quantification of radioactivity was validated. Storage phosphor plates showed an excellent linear range (approximately 10[3]) and acceptable resolution (approximately 0.5 mm). Receptor-ligand kinetics, including depletion, association and dissociation, saturation and displacement were evaluated with good results through the use of short-lived radiotracers and storage phosphor plates.

Botulinum neurotoxin F, a VAMP-specific endopeptidase, inhibits Ca(2+)-stimulated GH secretion from rat pituitary cells

Botulinum neurotoxin F (BoNTx F) is a zinc-dependent endopeptidase that causes proteolytic cleavage of the vesicle protein VAMP (vesicle-associated membrane protein). VAMP is an important component of the molecular machinery regulating docking and fusion of secretory vesicles with the target membrane. We have investigated presence of VAMP protein in cultured rat anterior pituitary cells. Confocal laser microscopy revealed presence of VAMP-like immunoreactivity in secretory granules of GH-containing cultured rat anterior pituitary cells. Using BoNTx F, we have investigated whether VAMP is involved in growth hormone (GH) secretion. Treatment of streptolysin-O permeabilized GH-secreting cells with BoNTx F (2.0 and 20 nM) significantly inhibited Ca(2+)-induced GH release. The results show that the secretory granules of rat anterior pituitary cell contain VAMP protein and suggest that VAMP is of importance in regulating Ca(2+)-mediated GH secretion.

High uptake of [2-11C]acetyl-L-carnitine into the brain: a PET study

The brain uptake of acetylcarnitine was investigated in rhesus monkeys using different position labeled acetyl-L-carnitine and related molecules with 11C by positron emission tomography. The uptake values of radio-labeled acetylcarnitine into the brain were quite different depending on the labeling positions of 11C. That is, the uptake values of L-[methyl-11C]carnitine and acetyl-L-[methyl-11C]carnitine were almost the same and extremely low, while the uptake of [1-11C]-acetyl-L-carnitine was slightly higher. The uptake value of [2-11C]acetyl-L-carnitine was by far the highest among the 11C-labeled acetyl-L-carnitine and L-carnitine. The uptake of [2-11C]acetyl-L-carnitine into the brain was suppressed by the intravenous administration of glucose. These results suggest that endogenous serum acetyl-L-carnitine has some roles on conveying an acetyl moiety into the brain especially under an energy crisis, and that an unknown metabolic pathway of [2-11C]acetyl moiety might be rather active in the brain.

Effects of routinely given pethidine during labour on infants' developing breastfeeding behaviour. Effects of dose-delivery time interval and various concentrations of pethidine/norpethidine in cord plasma

A standard dose of 100 mg of pethidine was given im to 13 healthy primiparae during labour. The aim of the study was to investigate whether developing breastfeeding behaviour in the newborn infant was associated with the dose-delivery time interval (DDI) or with the plasma concentration of pethidine and norpethidine in mixed cord blood at birth. The DDI was found to be unevenly distributed with no pethidine exposures in the time interval 5.4-8 h. The material was therefore divided into a "short DDI" group (1.1-5.3 h) and a "long DDI" group (8.1-9.9 h). The infants in the "short DDI" group had a depressed sucking behaviour in 15-45 min of observation and a delayed initiation of lip and mouth movements when compared with the infants in the "long DDI" group. Six of the thirteen infants did not suck their mothers' breasts during the observation period. These infants had higher median plasma concentrations of pethidine at birth than the seven infants who did start sucking. No differences wer found between the plasma levels of norpethidine and the behaviour. It was concluded that 100 mg of pethidine im as an analgesic given under routine conditions may have unfavourable effects on infants' developing breastfeeding behaviour if the DDI is short.

Molecular components of the exocytotic machinery in the rat pituitary gland

Several protein components that are essential for exocytotic membrane fusion in neurons have recently been identified. The expression and cellular localization of such protein components were examined in the rat pituitary gland. In situ hybridization using isoform-specific oligonucleotide probes to different exocytotic protein messenger RNAs (mRNAs) showed strong hybridization signal for synaptotagmin I, cysteine string protein (CSP), VAMP-2 (vesicle-associated membrane protein), cellubrevin, munc-18 (mammalian homologue of unc-18), SNAP-25a (synaptosomal-associated protein of 25 kDa), syntaxin 1A, syntaxin 4, syntaxin 5, and alpha-SNAP (soluble NSF attachment protein) in the anterior and intermediate, but not in the posterior lobe of the pituitary. Moderate to weak hybridization signal was detected for synaptotagmin III, SNAP-25b, and syntaxin 2 mRNA in the anterior and intermediate, but not in the posterior lobe of the pituitary. Synaptotagmin II, VAMP-1, syntaxin 1B, or syntaxin 3 mRNA expression could not be detected in any part of the pituitary gland. Immunofluorescence histochemistry in combination with confocal laser microscopy revealed that synaptotagmin-, VAMP-, CSP-, NSF-, and alpha-SNAP-like immunoreactivities (-LI) were present in granules of cells in the anterior and intermediate lobe, whereas SNAP-25- and syntaxin-LI were primarily located to the plasma membrane. Synaptotagmin-, VAMP-, CSP-, NSF-, alpha-SNAP-, SNAP-25- and syntaxin-LI were all present in nerve fibers of the posterior lobe. Within cells of the anterior lobe, colocalization could be demonstrated for synaptotagmin I/II- and synaptotagmin III-LI with ACTH-, GH-, PRL- and TSH-, but not FSH- or LH-LI, whereas VAMP, CSP-, NSF-, alpha-SNAP-, SNAP-25- and syntaxin-LI were demonstrated in all hormone-containing cell types of the anterior pituitary. The results show the presence of several protein components and their isoform-specific mRNAs in the rat pituitary gland, suggesting that these proteins, similar to their roles in regulation of synaptic neurotransmitter release, may participate in exocytotic events in endocrine pituitary cells and in neurosecretory nerve endings of the neurohypophysis.

Catechol-O-methyltransferase inhibition increases the uptake of 11C-3-(3,4-dihydroxyphenyl)-L-alanine in the rat pancreas

BACKGROUND

The objective of the present investigation was to evaluate the uptake and metabolism of 3-(3,4-dihydroxyphenyl-L-alanine) (L-DOPA) in the rat pancreas.

METHODS

The procedure included intravenous injection of the positron-emitting radiotracer L-[beta-11C] DOPA (DOP) into unanaesthetized male Sprague-Dawley rats and evaluation of uptake of radioactivity in organs in animals only given the tracer and in animals given therapeutic doses of three different catechol-O-methyltransferase (COMT) inhibitors, OR-486, OR-611, or Ro 41-0960. Selected pancreati were homogenized, and the chemical form bearing the radioactivity was analysed with high-performance liquid chromatography (HPLC).

RESULTS

The main finding was that the tracer uptake in the pancreas increased fourfold when the rats were pretreated with COMT inhibitors. Half maximum effect of OR-486 was found at a dose of 0.2 mg/kg. HPLC analysis showed that with COMT inhibitor, the radioactivity in the pancreas consisted of 90% DOPAC. When administering MAO-A and COMT inhibitor together, the pancreas radioactivity corresponded to dopamine. Also in the pig pancreas a significant increase of DOP was observed after COMT inhibition.

CONCLUSIONS

This study has shown a high turnover of L-DOPA in the rat pancreas, which can be modulated to give enhanced levels of DOPAC or dopamine by COMT and MAO inhibition.

Acylcarnitine metabolism during fasting and after refeeding

Carnitine metabolism during starvation and just after refeeding was studied by the measurement of acylcarnitine (ACR) and total carnitine (TCR) concentration in the serum and liver of mice. Starvation caused marked increases in the concentration of serum ACR, and of acid-soluble ACR in the liver. The refeeding caused the quick decrement of serum ACR with a concomitant marked increase in the level of acid-soluble TCR in the liver. Through the use of positron emission tomography in a rhesus monkey, a marked increase in [2-11C]acetyl-L-carnitine uptake in the liver was observed after the administration of glucose accompanying the decrease of serum ACR. From this study, it is clear that the mammalian liver can salvage and conserve the unused ACR when the state of energy metabolism is improved.

Chemotherapy improves survival and quality of life in advanced pancreatic and biliary cancer

BACKGROUND

In certain patients with pancreatic and biliary cancer, chemotherapy may relieve tumour-related symptoms, improve quality of life and possibly prolong survival. The extent of these improvements is not completely known in spite of the extensive use of this treatment modality. The aim of this study was to estimate any gain in the quantity and quality of life produced by chemotherapy in patients with pancreatic and biliary cancer.

PATIENTS AND METHODS

Between January 1991 and February 1995, 90 eligible patients with pancreatic or biliary cancer were randomized to either chemotherapy in addition to best supportive care or to best supportive care. Chemotherapy was allowed in the latter group if the supportive measures did not lead to palliation. Chemotherapy was either sequential 5-fluorouracil/leucovorin combined with etoposide (FELv) or, in elderly and poor performance patients, the same regimen without etoposide (FLv). Quality of life was evaluated with the EORTC-QLQ-C30 instrument.

RESULTS

Mean scale scores in the QLQ-C30 improved more often/deteriorated less frequently in the chemotherapy group than in the best supportive care group. More patients in the chemotherapy group (36%, 17/49) had an improved or prolonged high quality of life for a minimum period of 4 months compared to those in the best supportive care group (10%, 4/41, P < 0.01). Overall survival was significantly longer in the chemotherapy group (median 6 vs. 2.5 months, P < 0.01). Also, the quality-adjusted survival time was longer for patients randomized to chemotherapy (median 4 vs. 1 months, P < 0.01). The effects were seen both in pancreatic and biliary cancer.

CONCLUSIONS

The results show that chemotherapy can add to both quantity and quality of life in advanced pancreatic and biliary cancer. The number of patients who benefit from treatment is, however, still limited; for this reason careful selection before, and close monitoring during, treatment are necessary.

Levodopa-induced changes in synaptic dopamine in patients with Parkinson's disease as measured by [11C]raclopride displacement and PET

Changes in striatal binding of [11C]raclopride, a dopamine D2 receptor antagonist, induced by acute levodopa administration, were evaluated with PET in 10 patients with idiopathic Parkinson's disease (PD). The patients were scanned on two occasions: drug-free and 15 minutes after a 5-minute intravenous infusion of 3 mg/kg levodopa. Levodopa administration produced reductions in striatal [11C]raclopride uptake index with a rostrocaudal gradient. The most pronounced reduction was found in the posterior putamen (to 82% of baseline), followed by the anterior putamen (to 88% of baseline) and the caudate nucleus (to 94% of baseline). The magnitude of [11C]raclopride uptake index reduction correlated with drug-free disability. Moreover, in four hemiparkinsonian patients, a reduction in [11C]raclopride uptake index was measured in the putamen contralateral to the parkinsonian symptoms. The present results demonstrate a positive correlation between striatal dopaminergic nerve-terminal deficiency and the capacity for levodopa to increase synaptic dopamine and displace [11C]raclopride binding, which corresponds to an accelerated amine turnover in dopamine-depleted striatal tissue. We therefore suggest that dopaminergic degeneration in PD is paralleled by a progressive acceleration of amine turnover. This mechanistic consequence of nigrostriatal degeneration, the selective restoration of synaptic dopaminergic neurotransmission in denervated striatal subregions, may explain the effectiveness of levodopa in producing symptomatic benefits in early PD. However, we also suggest that in the vastly denervated striatum, as in advanced PD, an excessive acceleration of amine turnover results in swings in levodopa-induced synaptic dopamine levels that are far beyond normal. This phenomenon most likely plays a key role in the pathogenesis underlying the development of motor-response complications in PD.

Differential subcellular localization of SNAP-25a and SNAP-25b RNA transcripts in spinal motoneurons and plasticity in expression after nerve injury

Synaptosomal-associated protein of 25 kDa (SNAP-25) is involved in the molecular regulation of neurotransmitter release. SNAP-25 exists in two isoforms, which arise from alternative splicing of exon 5. In situ hybridization was used to examine whether SNAP-25 isoform mRNA expression may be altered by experimental manipulations. The effect of unilateral nerve injury on SNAP-25 mRNA levels was studied in motoneurons of the rat lumbar spinal cord. In all animals, SNAP-25a RNA transcripts were demonstrated in the nucleus of motoneurons, whereas SNAP-25b mRNA was present mainly in the cytoplasm. Cloning of the rat Snap gene intron spacing the alternative exon 5a and 5b sequences and generation of an intron-specific oligonucleotide probe used for in situ hybridization did not point to the presence of unspliced variants of SNAP-25b mRNA. After unilateral sciatic nerve transection (axotomy), SNAP-25a and SNAP-25b expression decreased in axotomized motoneurons compared with corresponding motoneurons on the unlesioned side. A significant decrease was demonstrated 2 days after axotomy, which reached a maximum after 7 days (62% for SNAP-25a and 67% for SNAP-25b), while levels had slightly recovered by 14 and 28 days. Ventral root avulsion also induced a decrease in levels of SNAP-25 RNA transcripts, suggesting that the axonal injury in itself was responsible for the down-regulation of Snap gene expression. This study shows that, in spinal motoneurons, SNAP-25a and SNAP-25b RNA transcripts have different subcellular localization and that levels of SNAP-25 RNA transcripts are down-regulated after axonal injury.

Expression of protein kinase C isoforms in renal tissue

PKC plays a central role for the regulation of renal function. PKC consists of a family of isoenzymes. By employing Northern blot techniques we have demonstrated that mRNA transcripts for the classical Ca(2+)-dependent, diacylglycerol-activated isoform alpha, the novel, Ca(2+)-independent isoform delta and the atypical isoform zeta are abundantly expressed in the rat kidney. The novel PKC-epsilon was weakly expressed. The classical PKCs beta I, beta II and gamma could not be detected. The mRNA expression of PKC-delta and -zeta increased with age. The intrarenal localization of PKC-alpha, -delta and -zeta isoforms were studied in the adult kidney using in situ hybridization. In the cortex, the PKC-alpha isoform showed the strongest hybridization signal. PKC alpha, delta and zeta were all distributed in the outer medulla. The PKC-alpha probe detected particularly strong signal in the outer stripe of the outer medulla. Western blot confirmed the presence of the PKC-alpha, -delta and -zeta enzymes in renal tissue. The results show cell-specific and developmentally-dependent expression of three types of PKC isoforms with different responses to diacylglycerol and calcium. The developmental increase of both PKC-delta and PKC-zeta suggests a specific role for these isoforms for the functional regulation of the mature kidney.

Identification of synaptic proteins and their isoform mRNAs in compartments of pancreatic endocrine cells

Several proteins that are of importance for membrane trafficking in the nerve terminal have recently been characterized. We have used Western blot and immunohistochemistry to show that synaptotagmin, synaptobrevin/VAMP (vesicle-associated membrane protein), SNAP-25 (synaptosomal-associated protein of 25 kDa), and syntaxin proteins are present in cells of the islets of Langerhans in the endocrine pancreas. Synaptotagmin-like immunoreactivity (-LI) was localized to granules within the cytoplasm of a few endocrine cells located in the periphery of the islets, identified as somatostatin-containing cells, and in many nerve fibers within the islets. VAMP-LI was seen in granules of virtually all pancreatic islet cells and also in nerve fibers. SNAP-25-LI and syntaxin-LI were predominantly present in the plasma membrane of the endocrine cells, including insulin-producing beta cells. In situ hybridization, using isoform-specific oligonucleotide probes, detected VAMP-2, cellubrevin, SNAP-25, syntaxin 1A, 4, and 5, and munc-18 mRNAs in isolated pancreatic islets and in insulin-producing cells. The results show the presence of several synaptic proteins at protein and mRNA levels in pancreatic islet cells, suggesting that they may have specific roles in the molecular regulation of exocytosis also in insulin-secreting cells.

Hexokinase I messenger RNA in the rat central nervous system

Hexokinase I (ATP:D-hexose 6-phosphotransferase, EC 2.7.1.1) is the first enzyme required in the metabolism of glucose in the central nervous system and plays a major role in regulation of the cerebral glycolytic rate. The distribution of hexokinase I mRNA was examined throughout the central nervous system of the rat by use of oligonucleotide probes and in situ hybridization histochemistry. In the rhinencephalon, strong hexokinase I mRNA labeling was demonstrated in the glomerular, mitral, internal granular, and internal plexiform layers, whereas the olfactory nerve, external plexiform, and subependymal layers and ependyma were devoid of labeling. Within the telencephalon, strong labeling was present in all layers (with the exception of the molecular layer) of the cerebral cortex, in the septum, in CA1-4 and dentate gyrus of the hippocampus, and in several amygdaloid nuclei. There was only weak labeling in the nucleus accumbens and caudate putamen. In the diencephalon, there was in general a strong labeling in the epithalamus, in several thalamic nuclei, including the anteriodorsal, anterioventral, anteriomedial, reticular, paravetricular, intermediodorsal, anteriomedial, interanteriomedial, rhomboid, reuniens, and parafascicular thalamic nuclei. Several hypothalamic regions, including the subfornical organ, the medial preoptic area, the suprachiasmatic, supraoptic, paraventricular, dorsomedial, ventromedial nuclei, and the zona incerta, were strongly labeled. In the mesencephalon, there was particularly strong labeling in the pars compacta and reticulata of the substantia nigra, central gray, and red nucleus, in the Darkschewitsch nucleus, and in the medial accessory oculomotor nucleus. In the rhombencephalon, there was strong hybridization in all raphe nuclei, pontine, tegmental, lateral parabrachial, olivary nuclei, and several cranial motor nuclei. All neurons of the locus ceruleus were heavily labeled. Very strong labeling was present in Purkinje and granular cells of the cerebellar cortex. Neurons of the medulla oblongata area postrema, nucleus tractus solitarius, reticular nucleus, nucleus cuneatus and several motor nuclei were strongly labeled. In the spinal cord, labeled cells were present in all laminae, and also neurons of the dorsal root ganglion were heavily labeled. Hexokinase I mRNA was also demonstrated in the epithelium lining the the choroid plexus. In the E15 fetus, very strong labeling was seen in the liver, heart, and trigeminal ganglion, with less intense labeling in in the brain and other tissues having more moderate labeling. Administration of 2% saline as drinking water resulted in a marked increase in hexokinase I mRNA in the magnocellular neurons of the supraoptics and paraventricular nuclei. In summary, the results show extensive neuronal distribution of hexokinase I mRNA with regional differences in the expression pattern.

Segment-specific expression of messenger RNA encoding for a glutamate transporter by renal tubule cells

Transport of the amino acid glutamate across plasma membranes of neurons, glial cells and epithelial cells of the small intestine and kidney is carried out via specific transport proteins. Recently, a high-affinity Na(+)-dependent glutamate transporter was cloned from rabbit small intestine. We have designed oligonucleotide probes to sequences of rabbit glutamate transporter mRNA and used these for in situ hybridization histochemistry in order to define the cellular localization of glutamate transporter mRNA in the rabbit kidney. Strong hybridization with the probes to glutamate transporter mRNA was demonstrated in the outer stripe of the outer medulla, with tubular rays radiating into the cortex. In emulsion-dipped and hematoxylin-eosin counterstained sections, it could be seen that cells expressing glutamate transporter mRNA were localized in the outer stripe of the outer medulla, coinciding with the S3 segment of proximal tubules. The results show that glutamate transporter mRNA is expressed in proximal tubule cells of the rabbit kidney, suggesting that Na(+)-dependent uptake of glutamate occurs primarily within this nephron segment.

Glutamate transporter mRNA and glutamate-like immunoreactivity in spinal motoneurones

Glutamate is the major excitatory neurotransmitter in the central nervous system. The release of glutamate is terminated by rapid uptake of glutamate into the presynaptic nerve terminals and into surrounding glial cells. Recently, a neuronal glutamate transporter was cloned from rabbit small intestine, thereby providing the possibility to study the distribution of cells that express glutamate transporter mRNA. Using oligonucleotide probes and in situ hybridization, glutamate transporter mRNA was demonstrated in large cell bodies, presumably motoneurones, in the thoracic spinal cord of the rabbit. Immunohistochemical analysis with rabbit polyclonal antibodies to glutamate showed immunoreactivity in the cytoplasm of large cell bodies in the ventral horn, presumably motoneurones, of the rat spinal cord. Glutamate-LI was in addition demonstrated in the motor end plate in hindlimb muscle of the rat, as visualized by double-labelling with mouse monoclonal antibodies to synaptophysin. Taken together, these data raise the possibility that glutamate has a function at the vertebrate neuromuscular junction.

Time course of ethanol-induced changes in serotonin metabolism

The effect of acute ethanol consumption on serotonin metabolism was examined in healthy volunteers in the fasted and fed state by determination of plasma and urinary levels of the serotonin metabolites 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL). The plasma and urinary levels of 5-HIAA were reduced by about 40% and 25%, while the 5-HTOL levels were increased on an average 7-fold and 50-fold, respectively, after oral intake of ethanol (0.8 g/kg) over 30 min in a fasted state. The maximal effect on both 5-HIAA and 5-HTOL levels was found 4-6 h after starting drinking. Urinary 5-HTOL and the 5-HTOL/5-HIAA ratio did not return to baseline until 19 h after the start of the administration (i.e., about 10 h after ethanol reached zero level). The mean 24-h excretion of 5-HTOL was increased 15-fold by the ethanol intake, while the 5-HIAA excretion was not significantly different. A clear dose dependent effect was observed in one individual who also ingested a lower amount of ethanol (0.5 g/kg). When ethanol (0.8 g/kg) was ingested over 3 h together with food, the urinary level of 5-HTOL and the 5-HTOL/5-HIAA ratio did not return to baseline until after 20-22 h. In other subjects who had unlimited access to ethanol and ingested between 1.3-2.3 g/kg together with food, the time to reach baseline 5-HTOL/5-HIAA ratio in urine ranged from 20 h to over 26 h.

Urinary excretion of 5-hydroxyindole-3-acetic acid and 5-hydroxytryptophol after oral loading with serotonin

The urinary excretion patterns of the serotonin (5-hydroxytryptamine; 5-HT) metabolites 5-hydroxyindole-3-acetic acid (5-HIAA) and 5-hydroxytryptophol (5-HTOL) were examined after ingestion of bananas, a food rich in 5-HT. The bananas contained on an average 25 micrograms 5-HT/g pulp. Both urinary 5-HIAA and 5-HTOL increased markedly (15- to 30-fold) shortly after eating 3-4 bananas, with the highest concentrations found in urine specimens collected after 2-4 h, and did not return to normal until after 8-10 h. The excretion of 5-HIAA increased from a control mean value of 3.9 mg/24 h to 12.7 mg/24 h, when conventional diets were supplemented with 3-4 bananas. The corresponding results for 5-HTOL were 16.8 micrograms/24 h and 60.7 micrograms/24 h, respectively. Of the banana-derived 5-HT ingested, 60-80% was recovered in the urine as 5-HIAA and only 0.3-0.5% as 5-HTOL. However, since both the time-course and relative increase in 5-HTOL was similar to that of 5-HIAA, there was no effect on the urinary 5-HTOL to 5-HIAA ratio. By contrast, acute alcohol consumption produced a considerable elevation of this ratio.

Chiral analysis of methadone in plasma by high-performance liquid chromatography

A method for the chiral high-performance liquid chromatographic analysis of methadone in plasma has been developed. The method employed organic solvent extraction, enantiomeric separation on a Chiral AGP column, and ultraviolet absorption detection at 212 nm. The intra-day variation in the quantification of methadone enantiomers was less than 9% at the 100 ng/ml level, and the values obtained correlated well with those from a gas chromatographic-mass spectrometric method. Results from patients indicate inter- and intra-individual differences in the ratio between l- and d-methadone in plasma during therapy with racemic methadone. In one patient, a higher level of d-methadone in plasma was caused by both faster elimination and lower bioavailability of l-methadone.

Determination of urinary 5-hydroxyindole-3-acetic acid by high-performance liquid chromatography with electrochemical detection and direct sample injection

A method for the routine quantitative determination of the major serotonin metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) in urine is described. 5-HIAA was analyzed without prior sample cleanup, using an automated high-performance liquid chromatography system with isocratic elution and electrochemical detection (+0.60 V versus a Ag/AgCl reference electrode). The urine samples were mixed with a solution of the internal standard (5-hydroxyindole-3-propionic acid) and centrifuged. The supernatant was transferred to sealed glass vials, and a 2-microliters aliquot was injected directly onto a C18 reversed-phase analytical column, using an automatic sample injector. Samples of urine could be stored for several months at -80 or at +7 degrees C for 2 days without loss of 5-HIAA. However, a gradual decline with time occurred in crude samples stored at room temperature or above, as well as in urine samples diluted with the mobile phase. The detector response was linear in the range of 0-65 mumol/l 5-HIAA, and the intra- and interassay coefficients of variation were about 5 and 7%, respectively (n = 10).

Monitoring of plasma methadone: intercorrelation between immunoassay and gas chromatography-mass spectrometry

Determination of plasma methadone is essential in connection with dose adjustments for patients participating in methadone maintenance programs. We successfully adapted the existing fluorescence polarization immunoassay (FPIA) kit intended for urinary methadone to plasma assays. A concentration interval of 50-900 ng/ml could be covered. The coefficient of variation was less than 7%, and the limit of detection below 50 ng/ml. The intercorrelation between the immunoassay and a specific gas chromatographic-mass spectrometric (GC-MS) method was studied in samples from 19 heroin addicts in methadone maintenance treatment. A total number of 97 plasma samples with a concentration range of 31-842 ng/ml were used. The slope and intercept of the regression line (CFPIA = 0.93 X CGC-MS + 15) was in good agreement with the theoretical relation (CFPIA = CGC-MS), with a coefficient of correlation of 0.978. The mean ratio, in quantitative result, between the techniques (CFPIA/CGC-MS) was 1.03 +/- 0.01 (SEM). We conclude that the immunoassay proposed in this study can be safely used in patients participating in methadone maintenance programs.

Isolation and characterization of neurokinin A, neurokinin A(3-10) and neurokinin A(4-10) from a neutral water extract of a metastatic ileal carcinoid tumour

A metastasis to the right liver lobe of an argyrophil/argentaffin midgut carcinoid tumour in a patient with the classical carcinoid syndrome was examined for the presence of tachykinins other than substance P, using a specific antiserum. The extract was initially purified using SepPak cartridges, and subsequently subjected to cation-exchange chromatography on SP Sephadex C-25 which separated the immunoreactive material into two main components (components I and II). Both were further purified by anion-exchange chromatography on DEAE-Sephadex A-25, and by reverse-phase fast protein liquid chromatography. Component II was identified as neurokinin A by its immunochemical and chromatographic properties and amino acid sequence analysis. Component I consisted of two molecular forms which were identified as neurokinin A(3-10) and neurokinin A(4-10) by amino acid sequence analysis. The tumour tissue contained only small amounts of the eledoisin-like peptide that has earlier been demonstrated in mammalian tissues. Although this component behaved like the nonmammalian peptide eledoisin on reverse-phase HPLC and on reverse-phase ion-pair chromatography, eledoisin-specific antiserum E2 indicated that eledoisin-like peptide is not identical to eledoisin. Neurokinin A in carcinoid tumours has an N-terminal heterogeneity; this multiplicity constitutes a further support for the hypothesis that carcinoid tumours produce a number of tachykinins which may be present in different relative amounts in individual patients and may contribute to the individual differences in symptomatology.

Effects of diazepam on blood choline and acetylcholine turnover in brain of mice

The effect of diazepam on the acetylcholine (ACh) synthesizing system has been studied in mouse brain in vivo. ACh and choline (Ch) were analyzed by gas chromatography - mass spectrometry using deuterated internal standards. Turnover of ACh was studied by following the incorporation of Ch into ACh after an intravenous injection of [2H6]-Ch. The mice were killed by focussed microwave irradiation on the head. Diazepam was found to increase the endogenous level of Ch, while the concentration of [2H6]-Ch was only half of that of the controls. The incorporation of [2H6]-Ch into [2H6]-ACh was decreased, while the endogenous level of ACh was slightly increased. The turnover rate of ACh was decreased, consistent with a decrease in neuronal excitability induced by diazepam. The elevated endogenous Ch-level and the lower concentration of [2H6]-Ch in the brain, might be explained by an effect of diazepam on the Ch-transport across the blood-brain barrier. This theory is supported by experiments where levels of endogenous and [2H6]-labelled Ch were analyzed in blood following an intravenous injection of [2H6]-Ch. The [2H6]-Ch was found to be eliminated faster in blood from diazepam treated mice. The increased blood level of endogenous Ch, induced by the [2H6]-Ch injection also returned more rapidly to normal in these animals. This is consistent with peripheral Ch being eliminated faster when the central Ch supply is decreased.

Rupture of an abdominal aortic aneurysm into the vena cava

Aortic abdominal aneurysm combined with aorto-caval fistula is a rare condition with a high mortality. We discuss here the sympatomatology and treatment of one such patient.