Increased insulin sensitivity and obesity resistance in mice lacking the protein tyrosine phosphatase-1B gene

Protein tyrosine phosphatase-1B (PTP-1B) has been implicated in the negative regulation of insulin signaling. Disruption of the mouse homolog of the gene encoding PTP-1B yielded healthy mice that, in the fed state, had blood glucose concentrations that were slightly lower and concentrations of circulating insulin that were one-half those of their PTP-1B+/+ littermates. The enhanced insulin sensitivity of the PTP-1B-/- mice was also evident in glucose and insulin tolerance tests. The PTP-1B-/- mice showed increased phosphorylation of the insulin receptor in liver and muscle tissue after insulin injection in comparison to PTP-1B+/+ mice. On a high-fat diet, the PTP-1B-/- and PTP-1B+/- mice were resistant to weight gain and remained insulin sensitive, whereas the PTP-1B+/+ mice rapidly gained weight and became insulin resistant. These results demonstrate that PTP-1B has a major role in modulating both insulin sensitivity and fuel metabolism, thereby establishing it as a potential therapeutic target in the treatment of type 2 diabetes and obesity.

Uncoupling protein-2: a novel gene linked to obesity and hyperinsulinemia

A mitochondrial protein called uncoupling protein (UCP1) plays an important role in generating heat and burning calories by creating a pathway that allows dissipation of the proton electrochemical gradient across the inner mitochondrial membrane in brown adipose tissue, without coupling to any other energy-consuming process. This pathway has been implicated in the regulation of body temperature, body composition and glucose metabolism. However, UCP1-containing brown adipose tissue is unlikely to be involved in weight regulation in adult large-size animals and humans living in a thermoneutral environment (one where an animal does not have to increase oxygen consumption or energy expenditure to lose or gain heat to maintain body temperature), as there is little brown adipose tissue present. We now report the discovery of a gene that codes for a novel uncoupling protein, designated UCP2, which has 59% amino-acid identity to UCP1, and describe properties consistent with a role in diabetes and obesity. In comparison with UCP1, UCP2 has a greater effect on mitochondrial membrane potential when expressed in yeast. Compared to UCP1, the gene is widely expressed in adult human tissues, including tissues rich in macrophages, and it is upregulated in white fat in response to fat feeding. Finally, UCP2 maps to regions of human chromosome 11 and mouse chromosome 7 that have been linked to hyperinsulinaemia and obesity. Our findings suggest that UCP2 has a unique role in energy balance, body weight regulation and thermoregulation and their responses to inflammatory stimuli.

Disruption of the uncoupling protein-2 gene in mice reveals a role in immunity and reactive oxygen species production

The gene Ucp2 is a member of a family of genes found in animals and plants, encoding a protein homologous to the brown fat uncoupling protein Ucp1 (refs 1-3). As Ucp2 is widely expressed in mammalian tissues, uncouples respiration and resides within a region of genetic linkage to obesity, a role in energy dissipation has been proposed. We demonstrate here, however, that mice lacking Ucp2 following targeted gene disruption are not obese and have a normal response to cold exposure or high-fat diet. Expression of Ucp2 is robust in spleen, lung and isolated macrophages, suggesting a role for Ucp2 in immunity or inflammatory responsiveness. We investigated the response to infection with Toxoplasma gondii in Ucp2-/- mice, and found that they are completely resistant to infection, in contrast with the lethality observed in wild-type littermates. Parasitic cysts and inflammation sites in brain were significantly reduced in Ucp2-/- mice (63% decrease, P<0.04). Macrophages from Ucp2-/- mice generated more reactive oxygen species than wild-type mice (80% increase, P<0.001) in response to T. gondii, and had a fivefold greater toxoplasmacidal activity in vitro compared with wild-type mice (P<0.001 ), which was absent in the presence of a quencher of reactive oxygen species (ROS). Our results indicate a role for Ucp2 in the limitation of ROS and macrophage-mediated immunity.

The role of psychological and biological factors in postinfective gut dysfunction

BACKGROUND

Both psychological and physiological disturbances have been implicated in the aetiopathogenesis of irritable bowel syndrome (IBS).

AIMS

To investigate how the psychological factors act, and the involvement of infective and physiological factors.

METHODS

Consecutive patients hospitalised for gastroenteritis reported life events for the previous 12 months, and past illness experiences on standardised questionnaires. They also completed psychometric questionnaires for anxiety, neuroticism, somatisation, and hypochondriasis. In some patients, rectal biopsy specimens were obtained during the acute illness and at three months postinfection.

RESULTS

Ninety four patients completed all questionnaires: 22 patients were diagnosed with IBS after their gastroenteritis (IBS+), and 72 patients returned to normal bowel habits (IBS-). IBS+ patients reported more life events and had higher hypochondriasis scores than IBS- patients. The predictive value of the life event and hypochondriasis measures was highly significant and independent of anxiety, neuroticism, and somatisation scores, which were also elevated in IBS+ patients. Rectal biopsy specimens from 29 patients showed a chronic inflammatory response in both IBS+ and IBS- patients. Three months later, specimens from IBS+ patients continued to show increased chronic inflammatory cell counts but those from IBS- patients had returned to normal levels. IBS+ and IBS- patients exhibited rectal hypersensitivity and hyper-reactivity and rapid colonic transit compared with normal controls, but there were no significant differences between IBS+ and IBS- patients for these physiological measurements.

CONCLUSION

Psychological factors most clearly predict the development of IBS symptoms after gastroenteritis but biological mechanisms also contribute towards the expression of symptoms.

Natural history of cervical human papillomavirus infection in young women: a longitudinal cohort study

BACKGROUND

Laboratory and epidemiological research suggests an association between human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN). We studied the natural history of incident cervical HPV infection and its relation to the development of CIN.

METHODS

We recruited 2011 women aged 15-19 years who had recently become sexually active. We took a cervical smear every 6 months and stored samples for virological analysis. We immediately referred all women with any cytological abnormality for colposcopic assessment, but postponed treatment until there was histological evidence of progression to high-grade CIN.

FINDINGS

In 1075 women who were cytologically normal and HPV negative at recruitment, the cumulative risk at 3 years of any HPV infection was 44% (95% CI 40-48): HPV 16 was the most common type. The cumulative risk at 3 years of detecting an HPV type not present in the first positive sample was 26% (20-32). 246 women had an abnormal smear during follow-up, of whom 28 progressed to high-grade CIN. The risk of high-grade CIN was greatest in women who tested positive for HPV 16 (risk ratio 8.5 [3.7-19.2]); this risk was maximum 6-12 months after first detection of HPV 16. All HPV types under consideration were associated with cytologically abnormal smears. Although abnormality was significantly less likely to be associated with low-viral-load samples, the cumulative risk at 3 years of a high-viral-load sample after a low-viral-load sample was 45% (95% CI 35-56). Five women who progressed to high-grade CIN consistently tested negative for HPV.

INTERPRETATION

Our findings suggest that attempts to exploit the association between cervical neoplasia and HPV infection to improve effectiveness of cervical screening programmes might be undermined by the limited inferences that can be drawn from the characterisation of a woman's HPV status at a single point in time, and the short lead time gained by its detection.

Frozen vs Fresh Fecal Microbiota Transplantation and Clinical Resolution of Diarrhea in Patients With Recurrent Clostridium difficile Infection: A Randomized Clinical Trial

IMPORTANCE

Clostridium difficile infection (CDI) is a major burden in health care and community settings. CDI recurrence is of particular concern because of limited treatment options and associated clinical and infection control issues. Fecal microbiota transplantation (FMT) is a promising, but not readily available, intervention.

OBJECTIVE

To determine whether frozen-and-thawed (frozen, experimental) FMT is noninferior to fresh (standard) FMT in terms of clinical efficacy among patients with recurrent or refractory CDI and to assess the safety of both types of FMT.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind, noninferiority trial enrolling 232 adults with recurrent or refractory CDI, conducted between July 2012 and September 2014 at 6 academic medical centers in Canada.

INTERVENTIONS

Patients were randomly allocated to receive frozen (n = 114) or fresh (n = 118) FMT via enema.

MAIN OUTCOMES AND MEASURES

The primary outcome measures were clinical resolution of diarrhea without relapse at 13 weeks and adverse events. Noninferiority margin was set at 15%.

RESULTS

A total of 219 patients (n = 108 in the frozen FMT group and n = 111 in the fresh FMT group) were included in the modified intention-to-treat (mITT) population and 178 (frozen FMT: n = 91, fresh FMT: n = 87) in the per-protocol population. In the per-protocol population, the proportion of patients with clinical resolution was 83.5% for the frozen FMT group and 85.1% for the fresh FMT group (difference, -1.6% [95% CI, -10.5% to ∞]; P = .01 for noninferiority). In the mITT population the clinical resolution was 75.0% for the frozen FMT group and 70.3% for the fresh FMT group (difference, 4.7% [95% CI, -5.2% to ∞]; P < .001 for noninferiority). There were no differences in the proportion of adverse or serious adverse events between the treatment groups.

CONCLUSIONS AND RELEVANCE

Among adults with recurrent or refractory CDI, the use of frozen compared with fresh FMT did not result in worse proportion of clinical resolution of diarrhea. Given the potential advantages of providing frozen FMT, its use is a reasonable option in this setting.

TRIAL REGISTRATION

clinicaltrials.gov Identifier:NCT01398969.

An intronless gene encoding a potential member of the family of receptors coupled to guanine nucleotide regulatory proteins

Plasma membrane receptors for hormones, drugs, neurotransmitters and sensory stimuli are coupled to guanine nucleotide regulatory proteins. Recent cloning of the genes and/or cDNAs for several of these receptors including the visual pigment rhodopsin, the adenylate-cyclase stimulatory beta-adrenergic receptor and two subtypes of muscarinic cholinergic receptors has suggested that these are homologous proteins with several conserved structural and functional features. Whereas the rhodopsin gene consists of five exons interrupted by four introns, surprisingly the human and hamster beta-adrenergic receptor genes contain no introns in either their coding or untranslated sequences. We have cloned and sequenced a DNA fragment in the human genome which cross-hybridizes with a full-length beta 2-adrenergic receptor probe at reduced stringency. Like the beta 2-adrenergic receptor this gene appears to be intronless, containing an uninterrupted long open reading frame which encodes a putative protein with all the expected structural features of a G-protein-coupled receptor.

Cloning of the cDNA for the human beta 1-adrenergic receptor

Screening of a human placenta lambda gt11 library has led to the isolation of the cDNA for the human beta 1-adrenergic receptor (beta 1AR). Used as the probe was the human genomic clone termed G-21. This clone, which contains an intronless gene for a putative receptor, was previously isolated by virtue of its cross hybridization with the human beta 2-adrenergic receptor (beta 2AR). The 2.4-kilobase cDNA for the human beta 1AR encodes a protein of 477 amino acid residues that is 69% homologous with the avian beta AR but only 54% homologous with the human beta 2AR. This suggests that the avian gene encoding beta AR and the human gene encoding beta 1AR evolved from a common ancestral gene. RNA blot analysis indicates a message of 2.5 kilobases in rat tissues, with a pattern of tissue distribution consistent with beta 1AR binding. This pattern is quite distinct from the pattern obtained when the beta 2AR cDNA is used as a probe. Expression of receptor protein in Xenopus laevis oocytes conveys adenylate cyclase responsiveness to catecholamines with a typical beta 1AR specificity. This contrasts with the typical beta 2 subtype specificity observed when the human beta 2AR cDNA is expressed in this system. Mammalian beta 1AR and beta 2AR are thus products of distinct genes, both of which are apparently related to the putative G-21 receptor.

The immunomodulation of enteric neuromuscular function: implications for motility and inflammatory disorders

Gastrointestinal motility and sensory perception are altered in a variety of mucosal inflammatory conditions of the gut, ranging from peptic esophagitis to ulcerative colitis. Studies in animal models now clearly indicate a causal relationship between the presence of mucosal inflammation and altered sensory-motor function. In many instances, these changes occur in the absence of any discernible encroachment of the deeper neuromuscular layers by the inflammatory infiltrate, which remains largely within the lamina propria. Accordingly, attention has focused on local sources of mediators, and recent studies indicate that smooth muscle cells and enteroglia are sources of and targets for cytokines such as interleukin 1 beta and interleukin 6. In several instances, neuromuscular dysfunction persists after mucosal inflammation has subsided; this state may be maintained by locally produced mediators. Studies also show the ability of enteric muscle to modulate lymphocyte function via major histocompatibility complex II-restricted antigen presentation. Clinical observation and experimental data also suggest that nerves modulate intestinal inflammation via local release of proinflammatory neuropeptides (substance P) and via the activation of extensive circuits that may involve the brain. Taken together, these findings provide plausible explanations for a variety of clinical scenarios ranging from inflammatory bowel disease to pseudo-obstruction syndromes and subgroups of functional bowel disorders.

Psychometric scores and persistence of irritable bowel after infectious diarrhoea

BACKGROUND

Although previous studies have shown that psychological disturbances are frequently associated with the irritable bowel syndrome (IBS), the relation was not necessarily cause and effect. The development of chronic bowel symptoms resembling IBS after an episode of acute gastroenteritis has allowed us to examine prospectively the role of psychological factors.

METHODS

75 patients with acute gastroenteritis completed a series of psychometric tests soon after admission to hospital. Of these, 22 had persistent symptoms compatible with IBS after the acute illness, and in 20 of these the symptoms were still present at six months.

FINDINGS

At the time of their initial illness, patients who subsequently developed IBS symptoms had higher scores for anxiety, depression, somatisation, and neurotic trait than those who returned to normal bowel function. The psychometric scores had not changed when remeasured three months after the acute illness. Lactose malabsorption was not an important factor.

INTERPRETATION

These results support the hypothesis that psychological factors are important in IBS.

Uncoupling protein 2, in vivo distribution, induction upon oxidative stress, and evidence for translational regulation

Uncoupling protein 2 (UCP2) belongs to the mitochondrial anion carrier family and partially uncouples respiration from ATP synthesis when expressed in recombinant yeast mitochondria. We generated a highly sensitive polyclonal antibody against human UCP2. Its reactivity toward mitochondrial proteins was compared between wild type and ucp2(-/-) mice, leading to non-ambiguous identification of UCP2. We detected UCP2 in spleen, lung, stomach, and white adipose tissue. No UCP2 was detected in heart, skeletal muscle, liver, and brown adipose tissue. The level of UCP2 in spleen mitochondria is less than 1% of the level of UCP1 in brown adipose tissue mitochondria. Starvation and LPS treatments increase UCP2 level up to 12 times in lung and stomach, which supports the hypothesis that UCP2 responds to oxidative stress situations. Stimulation of the UCP2 expression occurs without any change in UCP2 mRNA levels. This is explained by translational regulation of the UCP2 mRNA. We have shown that an upstream open reading frame located in exon two of the ucp2 gene strongly inhibits the expression of the protein. This further level of regulation of the ucp2 gene provides a mechanism by which expression can be strongly and rapidly induced under stress conditions.

Ecological forecasts: an emerging imperative

Planning and decision-making can be improved by access to reliable forecasts of ecosystem state, ecosystem services, and natural capital. Availability of new data sets, together with progress in computation and statistics, will increase our ability to forecast ecosystem change. An agenda that would lead toward a capacity to produce, evaluate, and communicate forecasts of critical ecosystem services requires a process that engages scientists and decision-makers. Interdisciplinary linkages are necessary because of the climate and societal controls on ecosystems, the feedbacks involving social change, and the decision-making relevance of forecasts.

Increased rectal mucosal expression of interleukin 1beta in recently acquired post-infectious irritable bowel syndrome

BACKGROUND AND AIMS

Chronic bowel disturbances resembling irritable bowel syndrome (IBS) develop in approximately 25% of patients after an episode of infectious diarrhoea. Although we have previously shown that psychosocial factors operating at the time of, or prior to, the acute illness appear to predict the development of post-infectious IBS (PI-IBS), our finding of an increased inflammatory cell number in the rectum persisting for at least three months after the acute infection suggested that there is also an organic component involved in the development of PI-IBS. To evaluate this further, we measured expressions of interleukin 1beta (IL-1beta) and its receptor antagonist (IL-1ra) in these patients to provide additional evidence that the pathogenesis of PI-IBS is underpinned by an inflammatory process.

METHODS

Sequential rectal biopsy samples were prospectively obtained during and three months after acute gastroenteritis, from eight patients who developed post-infectious IBS (INF-IBS) and seven patients who returned to normal bowel habits after acute gastroenteritis (infection controls, INF-CON). Eighteen healthy volunteers who had not suffered from gastroenteritis in the preceding two years served as normal controls (NOR-CON). IL-1beta and IL-1ra gene expressions were assayed by reverse transcriptase-polymerase chain reaction, and their levels of expression were quantitated by optical densitometry after electrophoresis on agarose gel.

RESULTS

INF-IBS patients exhibited significantly greater expression of IL-1beta mRNA in rectal biopsies than INF-CON patients both during and three months after acute gastroenteritis. Moreover, IL-1beta mRNA expression had increased in biopsies taken from INF-IBS patients at three months after the acute infection but no consistent change was observed in INF-CON patients. IL-1beta mRNA expression of INF-IBS patients at three months post gastroenteritis was significantly greater than NOR-CON whereas that of INF-CON patients was not significantly different from NOR-CON. Despite these differential changes in IL-1beta mRNA expression, no significant changes were observed in IL-1ra mRNA expression among the three groups.

CONCLUSIONS

These findings indicate that those patients who develop IBS post infection exhibit greater IL-1beta mRNA expression, both during and after the infection, compared with individuals who do not develop PI-IBS. We conclude that such patients may be susceptible to inflammatory stimuli, and that inflammation may play a role in the pathogenesis of PI-IBS.

Specific probiotic therapy attenuates antibiotic induced visceral hypersensitivity in mice

BACKGROUND AND AIMS

Abdominal pain and discomfort are common symptoms in functional disorders and are attributed to visceral hypersensitivity. These symptoms fluctuate over time but the basis for this is unknown. Here we examine the impact of changes in gut flora and gut inflammatory cell activity on visceral sensitivity.

METHODS

Visceral sensitivity to colorectal distension (CRD) was assessed at intervals in healthy mice for up to 12 weeks, and in mice before and after administration of dexamethasone or non-absorbable antibiotics with or without supplementation with Lactobacillus paracasei (NCC2461). Tissue was obtained for measurement of myeloperoxidase activity (MPO), histology, microbiota analysis, and substance P (SP) immunolabelling.

RESULTS

Visceral hypersensitivity developed over time in healthy mice maintained without sterile precautions. This was accompanied by a small increase in MPO activity. Dexamethasone treatment normalised MPO and CRD responses. Antibiotic treatment perturbed gut flora, increased MPO and SP immunoreactivity in the colon, and produced visceral hypersensitivity. Administration of Lactobacillus paracasei in spent culture medium normalised visceral sensitivity and SP immunolabelling, but not intestinal microbiota counts.

CONCLUSION

Perturbations in gut flora and in inflammatory cell activity alter sensory neurotransmitter content in the colon, and result in altered visceral perception. Changes in gut flora may be a basis for the variability of abdominal symptoms observed in functional gastrointestinal disorders and may be prevented by specific probiotic administration.

Prospective long-term study of vagus nerve stimulation for the treatment of refractory seizures

PURPOSE

To determine the long-term efficacy of vagus nerve stimulation (VNS) for refractory seizures. VNS is a new treatment for refractory epilepsy. Two short-term double-blind trials have demonstrated its safety and efficacy, and one long-term study in 114 patients has demonstrated a cumulative improvement in efficacy at 1 year. We report the largest prospective long-term study of VNS to date.

METHODS

Patients with six or more complex partial or generalized tonic-clonic seizures enrolled in the pivotal EO5 study were prospectively evaluated for 12 months. The primary outcome variable was the percentage reduction in total seizure frequency at 3 and 12 months after completion of the acute EO5 trial, compared with the preimplantation baseline. Subjects originally randomized to low stimulation (active-control group) were crossed over to therapeutic stimulation settings for the first time. Subjects initially randomized to high settings were maintained on high settings throughout the 12-month study.

RESULTS

The median reduction at 12 months after completion of the initial double-blind study was 45%. At 12 months, 35% of 195 subjects had a >50% reduction in seizures, and 20% of 195 had a >75% reduction in seizures.

CONCLUSIONS

The efficacy of VNS improves during 12 months, and many subjects sustain >75% reductions in seizures.

Rethrombosis after reperfusion with streptokinase: importance of geometry of residual lesions

We tested the hypothesis that lesion rethrombosis after streptokinase reperfusion is related to luminal size of the residual stenosis. Two independent techniques of analyzing coronary angiograms, quantitative coronary angiography and computer-based videodensitometry, were used to estimate the size of the residual lumen immediately after discontinuation of streptokinase. These techniques were selected because they provide independent estimates of cross-sectional area of a lesion with high degrees of reproducibility and minimal observer variability. Twenty-four patients who had undergone successful reperfusion with streptokinase were studied. Seven patients had lesion rethrombosis documented either on a repeat angiogram, at autopsy, or, in one case, by the fact that the patient had an acute transmural infarction resulting in death. Vessel patency was documented by repeat coronary angiography 8 to 14 days after initial streptokinase reperfusion in the other 17 patients. As assessed by quantitative coronary angiography, seven of 13 patients (54%) with minimal luminal cross-sectional areas of less than 0.4 mm2 had rethrombosis. None of the 11 patients with lumens greater than 0.4 mm2 had rethrombosis. In the 17 patients with vessels that remained patent the size of the residual lesion at repeat catheterization was compared with its size immediately after reperfusion with streptokinase. Over the intervening 8 to 14 day interval, an average percentage increase in minimal cross-sectional area of 116 +/- 34% was observed. In seven patients minimal luminal cross-sectional area more than doubled. Integrated optical density, an index of the severity of coronary stenosis derived from computer-based videodensitometry, was also useful in identifying a subgroup of patients at high risk for rethrombosis of lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzodiazepines in epilepsy: pharmacology and pharmacokinetics

Benzodiazepines (BZDs) remain important agents in the management of epilepsy. They are drugs of first choice for status epilepticus and seizures associated with post-anoxic insult and are also frequently used in the treatment of febrile, acute repetitive and alcohol withdrawal seizures. Clinical advantages of these drugs include rapid onset of action, high efficacy rates and minimal toxicity. Benzodiazepines are used in a variety of clinical situations because they have a broad spectrum of clinical activity and can be administered via several routes. Potential shortcomings of BZDs include tolerance, withdrawal symptoms, adverse events, such as cognitive impairment and sedation, and drug interactions. Benzodiazepines differ in their pharmacologic effects and pharmacokinetic profiles, which dictate how the drugs are used. Among the approximately 35 BZDs available, a select few are used for the management of seizures and epilepsy: clobazam, clonazepam, clorazepate, diazepam, lorazepam and midazolam. Among these BZDs, clorazepate has a unique profile that includes a long half-life of its active metabolite and slow onset of tolerance. Additionally, the pharmacokinetic characteristics of clorazepate (particularly the sustained-release formulation) could theoretically help minimize adverse events. However, larger, controlled studies of clorazepate are needed to further examine its role in the treatment of patients with epilepsy.

Somatostatinoma syndrome. Biochemical, morphologic and clinical features

Diabetes mellitus, steatorrhea, cholelithiasis and a tumor distorting the duodenum prompted a work-up for somatostatinoma in a 52-year-old man. The responses of pancreatic B-cells but not of A-cells to nutrient stimuli were inhibited, and growth-hormone release was suppressed, suggesting somatostatin resistance in some target tissues. Plasma somatostatin-like immunoreactivity ranged from 9000 to 13,000 pg per milliliter (normal: 88+/-8, mean +/- S.E.M.) and was distributed in four molecular forms, including free somatostatin. The primary tumor contained 5 microgram of somatostatin-like immunoreactivity per milligram of wet tissue, distributed in three of the molecular forms noted in plasma. Plasma calcitonin was also elevated (4650 pg per milliliter; normal: less than 120). Immunocytochemical studies showed that cells of the primary tumor contained somatostatin and calcitonin but no other peptide hormones. Only somatostatin was present in the metastases. Somatostatin was localized electron microscopically in all secretory granules, irrespective of size and shape, whereas calcitonin was present only within a single subpopulation of small granules in the same cells.

Guidelines for topical photodynamic therapy: report of a workshop of the British Photodermatology Group

Topical photodynamic therapy (PDT) is effective in the treatment of certain non-melanoma skin cancers and is under evaluation in other dermatoses. Its development has been enhanced by a low rate of adverse events and good cosmesis. 5-Aminolaevulinic acid (ALA) is the main agent used, converted within cells into the photosensitizer protoporphyrin IX, with surface illumination then triggering the photodynamic reaction. Despite the relative simplicity of the technique, accurate dosimetry in PDT is complicated by multiple variables in drug formulation, delivery and duration of application, in addition to light-specific parameters. Several non-coherent and coherent light sources are effective in PDT. Optimal disease-specific irradiance, wavelength and total dose characteristics have yet to be established, and are compounded by difficulties comparing light sources. The carcinogenic risk of ALA-PDT appears to be low. Current evidence indicates topical PDT to be effective in actinic keratoses on the face and scalp, Bowen's disease and superficial basal cell carcinomas (BCCs). PDT may prove advantageous where size, site or number of lesions limits the efficacy and/or acceptability of conventional therapies. Topical ALA-PDT alone is a relatively poor option for both nodular BCCs and squamous cell carcinomas. Experience of the modality in other skin diseases remains limited; areas where there is potential benefit include viral warts, acne, psoriasis and cutaneous T-cell lymphoma. A recent British Photodermatology Group workshop considered published evidence on topical PDT in order to establish guidelines to promote the efficacy and safety of this increasingly practised treatment modality.

The effect of coronary angioplasty on coronary flow reserve

To determine the effects of coronary angioplasty on coronary flow reserve (CFR), we studied 32 patients before and immediately after single-vessel coronary angioplasty and 31 patients evaluated late after angioplasty (7.5 +/- 1.2 months, mean +/- SEM). The geometry (percent area stenosis and minimal cross-sectional area) of each lesion was determined by quantitative coronary angiography (Brown/Dodge method) and the integrated optical density was measured by videodensitometry. CFR was measured with a No. 3F coronary Doppler catheter placed immediately proximal to the lesion and a maximally vasodilating dose of intracoronary papaverine. The translesional pressure gradient was obtained in all lesions before and immediately after angioplasty and in 18 of 31 vessels late after angioplasty. CFR immediately after angioplasty returned to normal levels (greater than 3.5 peak/resting velocity ratio) in 14 of 31 patients and was improved, although not normalized, in the remaining 17 patients. CFR immediately after dilation was not significantly correlated with any of the angiographic variables of arterial stenosis nor the resting pressure gradient. Moreover, the pressure gradient and absolute distal coronary pressure at peak hyperemia were not significantly different in vessels with normal and those with abnormal flow reserve immediately after dilation, suggesting that the residual stenosis did not significantly limit hyperemia. Late after angioplasty, however, a significant relationship emerged between CFR and all four indexes of residual arterial stenosis (percent area stenosis r = .70, p less than .01; minimum arterial cross-sectional area r = .70, p less than .01; integrated optical density r = .60, p less than .01; and translesional pressure gradient r = .77, p less than .01). Furthermore, in the absence of restenosis, CFR eventually normalized in all patients. These findings demonstrate that in one-half of patients there is a transient reduction in coronary flow reserve immediately after angioplasty. In the absence of restenosis, coronary flow reserve later normalizes. Consequently, measurements of coronary flow reserve immediately after angioplasty may not reflect the eventual success of the procedure in removing physiologic obstruction to coronary blood flow.

Analysis of EEG and CSF 14-3-3 proteins as aids to the diagnosis of Creutzfeldt-Jakob disease

OBJECTIVE

To improve diagnostic criteria for sporadic Creutzfeldt-Jakob disease (CJD).

METHODS

Pooled data on initial and final diagnostic classification of suspected CJD patients were accumulated, including results of investigations derived from a coordinated multinational study of CJD. Prospective analysis for a comparison of clinical and neuropathologic diagnoses and evaluation of the sensitivity and specificity of EEG and 14-3-3 CSF immunoassay were conducted.

RESULTS

Data on 1,003 patients with suspected CJD were collected using a standard questionnaire. After follow-up was carried out, complete clinical data and neuropathologic diagnoses were available in 805 cases. In these patients, the sensitivity of the detection of periodic sharp wave complexes in the EEG was 66%, with a specificity of 74%. The detection of 14-3-3 proteins in the CSF correlated with the clinical diagnosis in 94% (sensitivity). The specificity (84%) was higher than that of EEG. A combination of both investigations further increased the sensitivity but decreased the specificity.

CONCLUSIONS

Incorporation of CSF 14-3-3 analysis in the diagnostic criteria for CJD significantly increases the sensitivity of case definition. Amended diagnostic criteria for CJD are proposed.

beta-Adrenergic activation of p38 MAP kinase in adipocytes: cAMP induction of the uncoupling protein 1 (UCP1) gene requires p38 MAP kinase

Because of increasing evidence that G protein-coupled receptors activate multiple signaling pathways, it becomes important to determine the coordination of these pathways and their physiological significance. Here we show that the beta(3)-adrenergic receptor (beta(3)AR) stimulates p38 mitogen-activated protein kinase (p38 MAPK) via PKA in adipocytes and that cAMP-dependent transcription of the mitochondrial uncoupling protein 1 (UCP1) promoter by beta(3)AR requires p38 MAPK. The selective beta(3)AR agonist CL316,243 (CL) stimulates phosphorylation of MAP kinase kinase 3/6 and p38 MAPK in a time- and dose-dependent manner in both white and brown adipocytes. Isoproterenol and forskolin mimicked the effect of CL on p38 MAPK. In all cases activation was blocked by the specific p38 MAPK inhibitor SB202190 (SB; 1-10 microm). The involvement of PKA in beta(3)AR-dependent p38 MAPK activation was confirmed by the ability of the PKA inhibitors H89 (20 microm) and (R(p))-cAMP-S (1 mm) to block phosphorylation of p38 MAPK. Treatment of primary brown adipocytes with CL or forskolin induced the expression of UCP1 mRNA levels (6.8- +/- 0.8-fold), and this response was eliminated by PKA inhibitors and SB202190. A similar stimulation of a 3.7-kilobase UCP1 promoter by CL and forskolin was also completely inhibited by PKA inhibitors and SB202190, indicating that these effects on UCP1 expression are transcriptional. Moreover, the PKA-dependent transactivation of the UCP1 promoter, as well as its sensitivity to SB202190, was fully reproduced by a 220-nucleotide enhancer element from the UCP1 gene. We similarly observed that increased phosphorylation of ATF-2 by CL was sensitive to both H89 and SB202190, while phosphorylation of cAMP-response element-binding protein was inhibited only by H89. Together, these studies illustrate that p38 MAPK is an important downstream target of the beta-adrenergic/cAMP/PKA signaling pathway in adipocytes, and one of the functional consequences of this cascade is stimulation of UCP1 gene expression in brown adipocytes.

Microbes and the gut-brain axis

BACKGROUND

The 'gut-brain' or 'brain-gut axis', depending on whether we emphasize bottom-up or top-bottom pathways, is a bi-directional communication system, comprised of neural pathways, such as the enteric nervous system (ENS), vagus, sympathetic and spinal nerves, and humoral pathways, which include cytokines, hormones, and neuropeptides as signaling molecules. Recent evidence, mainly arising from animal models, supports a role of microbes as signaling components in the gut-brain axis.

AIMS

The purpose of this review is to summarize our current knowledge regarding the role of microbes, including commensals, probiotics and gastrointestinal pathogens, in bottom-up pathways of communication in the gut-brain axis. Although this has clear implications for psychiatric co-morbidity in functional and inflammatory conditions of the gut, the focus of this review will be to discuss the current evidence for a role of bacteria (commensals, probiotics, and pathogens) as key modulators of gut-brain communication.

RESULTS & CONCLUSIONS

The strongest evidence for a role of microbes as signaling components in the gut-brain axis currently arises from animal studies and indicate that mechanisms of communication are likely to be multiple. There is need for the concepts generated in animal models to be translated to the human in the future.