Protective role of 3-nitro-N-methyl-salicylamide on isolated rat heart during 4 hours of cold storage and reperfusion

OBJECTIVE

Cardiac ischemia/reperfusion (I/R) injury, a necessary consequence of transplantation, is probably related to the formation of reactive oxygen species (ROS). The ROS burst within the first moments of reperfusion is associated with injury, continuously generate O2- at about 3% to 5% of total O2 consumption owing to electron leak by mitochondrial oxidoreductases, especially complexes I and III. 3-nitro-N-methyl-salicylamide (NNMS) displays inhibitory effects on succinate-cytochrome C reductase, but also reduces effects on creation of O2- radical and H2O2 by isolated rat mitochondria. Presumably NNMS inhibits electron leakage from the mitochondrial respiratory chain. We investigated effect of NNMS on heart protection after hypothermic ischemia.

METHODS

A Langendorff-prepared rat heart model was employed after the heart had been preserved for 4 hours under hypothermic conditions of ischemia with subsequent reperfusion/rewarming for 60 minutes.

RESULTS

The group of hearts treated with NNMS showed increased recovery of heart function compared with a group of mEC. The lactate dehydrogenase (LDH) activity in coronary flow (CF) by hearts treated with NNMS was lower than that with mECs, as was the content of malonedialdehyde (MDA) and conjugated diene (CD).

CONCLUSIONS

NNMS improved heart physiology after reperfusion following 4 hours of hypothermic ischemia.

Phase-1 study of isophosphoramide mustard (IPM)-lysine in advanced cancers

9524

Background: IPM is a bi-functional alkylator which cross-links DNA through G:C base-pairs resulting in irreparable 7-atom inter-strand cross-links. IPM is the active moiety of ifosfamide (IFOS), a pro-drug of IPM. IPM is active in diverse cancer models but is unstable. We stabilized IPM with lysine (IPM-lysine; ZIO-201). ZIO-201 was active in pre-clinical models including human cancer cell lines, human-mouse xenografts and cancers resistant to cyclophosphamide (CPA) and IFOS. Because ZIO-201 is not metabolized to acrolein or chloroacetaldehyde, bladder and CNS toxicities are unlikely. Methods: Phase-1 trial in subjects with advanced cancers. ZIO-201 was given daily for 3 consecutive d at a starting dose of 30 mg/me2/d every 3 w. Neither mesna nor IV hydration were given. 11 dose levels were studied in 18 subjects up to 795 mg/me2/d; dose-escalation continues. Data on the 1st 15 subjects are available for analysis. Results: Median age was 59 y (range, 18–70 y); 10 subjects were male. Diagnoses included colorectal cancer (N=5), sarcoma (N=3) and 1 subject each with gastric, lung, bladder, prostate, ovary and thyroid cancers and mesothelioma. 7 had extensive and 8, limited disease. All subjects received extensive prior therapy. Median N cycles was 2 (range, 1–13). Toxicities ≥ grade-2 occurring in > 20% of subjects included anemia (N subjects=4) and diverse GI complaints (N=4). 4 of 8 subjects receiving doses > 445 mg/me2/d had transient proximal renal tubular acidosis. There was no hemorrhagic cystitis or CNS toxicity. 1 subject with mesothelioma had stable disease > 13 mo. Pharmacokinetic studies at 595 mg/me2/d showed a tmax = 13 min (SD ± 9 min), Cmax = 44.7 μg/mL (SD ± 34.1 μg/mL), t1/2 = 35 min (SD ± 7 min) and AUC0-∞ = 1.68 mg·min/ml (SD ± 1.26 mg·min/ml). Conclusions: These data suggest a possible role for ZIO-201 in IFOS-sensitive cancers (especially sarcoma and lymphoma). ZIO-201 may also be active in CPA and IFOS-resistant cancers. Comparable or greater efficacy with less toxicity is expected.

[Table: see text]

Innovative technique for correction of the congenital lop ear

Congenital lop ear is a deformity affecting the upper third of the ear. It is characterised by varying degrees of lidding of the helix, reduction in the fossa triangularis, scapha compression, reduction or absence of the superior crus of the antihelix and an associated reduction in vertical height of the external ear. Reported strategies for the surgical correction of this deformity include simple excision of the excess overhanging cartilage, radial cartilage incisions of the helix to reverse its memory, various cartilage grafts from the surrounding ear or rib to strut or fill the defect, and mastoid hitching stitches to reinforce the repair. We present a novel technique using a reversed conchal cartilage graft to strut the deformed antihelix. The memory of the reversed conchal cartilage is used to correct lidding of the superior helix and obviates the need for intrinsic cartilage modification or excision. We have found a good aesthetic and structural result in a patient with bilateral congenital lop ear with 12 months follow up.

Marijuana use is associated with a reorganized visual-attention network and cerebellar hypoactivation

Attention and memory deficits have been reported in heavy marijuana users, but these effects may be reversible after prolonged abstinence. It remains unclear whether the reversibility of these cognitive deficits indicates that chronic marijuana use does not alter cortical networks, or that such changes occur but the brain adapts to the drug-induced changes. Blood oxygenation-level dependent (BOLD) functional MRI (fMRI) was performed in 24 chronic marijuana users (12 abstinent and 12 active) and 19 age-, sex- and education-matched control subjects during a set of visual-attention tasks with graded levels of difficulty. Neuropsychological tests were also administered on each subject. The two marijuana user groups showed no significant difference in usage pattern (frequency or duration of use, age of first use, cumulative joints used, averaged >2000 joints) or estimated cumulative lifetime exposure of Delta-9-tetrahydrocannabinol (THC) (mean 168 +/- 45 versus 244 +/- 135 g). Despite similar task and cognitive test performance compared with control subjects, active and abstinent marijuana users showed decreased activation in the right prefrontal, medial and dorsal parietal, and medial cerebellar regions, but greater activation in various frontal, parietal and occipital brain regions during the visual-attention tasks (all with P < or = 0.001, corrected, cluster level). However, the BOLD signals in the right frontal and medial cerebellar regions normalized with duration of abstinence in the abstinent users. Active marijuana users, with positive urine tests for THC, showed greater activation in the frontal and medial cerebellar regions than abstinent marijuana users and greater usage of the reserve network (regions with load effect), suggesting a neuroadaptive state. Both earlier age of first use and greater estimated cumulative dose of THC exposure were related to lower BOLD signals in the right prefrontal region and medial cerebellum. The altered BOLD activation pattern in the attention network and hypoactivation of the cerebellum suggest neuroadaptive processes or alteration of brain development in chronic marijuana users. These changes also may be related to marijuana-induced alteration in resting cerebral blood volume/flow or downregulation of cannabinoid (CB1) receptors. The greater activation in the active compared with abstinent marijuana users demonstrates a neuroadaptive state in the setting of active marijuana use, while the long-term chronic effect of marijuana on the altered brain network may be reversible with prolonged abstinence.

Cerebral metabolites in HIV-infected children followed for 10 months with 1H-MRS

BACKGROUND

Previous studies have shown that HIV-infected children have abnormal cerebral metabolites, measured by proton MR spectroscopy (1H MRS), but the stability of these measurements over time has not been described in HIV-infected children. The authors recently reported a study of cerebral metabolites in 20 HIV-infected children (6 to 16 years of age); the current study followed 12 of these children (10.0 years +/- 3.7 years) and repeated the MR spectroscopy at 24.1 +/- 3.7 weeks and 42.2 +/- 3.5 weeks following the entry time with repeated neuropsychological testing.

METHODS

1H MR spectra were acquired at 1.5 T (GE Signa, PRESS localization, repetition time = 3,000 msec, echo time = 30 msec). Five brain regions were studied: right frontal white matter, left frontal white matter, right basal ganglia, right hippocampus, and midfrontal gray matter. The concentrations of N-acetylaspartate (NAA), choline (CHO), creatine (CR), and myo-inositol (mI) and the ratio of each metabolite to CR were determined.

RESULTS

There were no changes in the metabolite concentrations or metabolite/CR ratios at the three time periods. Similarly, during this follow-up period, HIV-positive children showed no changes in clinical signs, HIV viral loads, CD4%, or CD4 counts, except for improved spatial memory with repeat testing.

CONCLUSION

In a clinically and neurologically stable group of HIV-infected children, cerebral metabolites were stable over a 10-month time period, suggesting that it is possible to assess changes in cerebral metabolites as a measure of cerebral health, but longer follow-up in a larger sample is needed.

Non-tuberculous mycobacteria in end stage cystic fibrosis: implications for lung transplantation

BACKGROUND

WC and NS contributed equally. Non-tuberculous mycobacteria (NTM) frequently colonise patients with end stage cystic fibrosis (CF), but its impact on the course of the disease following lung transplantation is unknown.

METHODS

Lung transplant recipients with CF who underwent lung transplantation at our institution between January 1990 and May 2003 (n=146) and CF patients awaiting lung transplantation in May 2003 (n=31) were studied retrospectively.

RESULTS

The prevalence rate of NTM isolated from respiratory cultures in patients with end stage CF referred for lung transplantation was 19.7%, compared with a prevalence rate of 13.7% for NTM isolates in CF lung transplant recipients. The overall prevalence of invasive NTM disease after lung transplantation was low (3.4%) and was predicted most strongly by pre-transplant NTM isolation (p=0.001, Fisher's exact test, odds ratio (OR) 6.13, 95% CI 3.2 to 11.4). This association was restricted to Mycobacterium abscessus (p = 0.005, Fisher's exact test, OR 7.45, 95% CI 2.9 to 16.9). While NTM disease caused significant morbidity in a small number of patients after transplantation, it was successfully treated and did not influence the post-transplant course of the disease.

CONCLUSION

The isolation of NTM before transplantation in CF patients should not be an exclusion criterion for lung transplantation, but it may alert the clinician to patients at risk of recurrence following transplantation.

Combined and independent effects of chronic marijuana use and HIV on brain metabolites

The effects of chronic marijuana (MJ) use on brain function remain controversial. Because MJ is often used by human immunodeficiency virus (HIV) patients, the aim of this study was to evaluate whether chronic MJ use and HIV infection are associated with interactive or additive effects on brain chemistry and cognitive function. We evaluated 96 subjects (30 seronegative nondrug users, 24 MJ users, 21 HIV without MJ use, 21 HIV + MJ) using proton magnetic resonance spectroscopy and a battery of neuropsychological tests. The two primarily abstinent MJ user groups showed no significant differences on calculated estimates of lifetime grams of delta9-tetrahydrocannabinol exposure, despite some differences in usage pattern. The two HIV groups also had similar HIV disease severity (CD4 cell count, plasma viral load, HIV dementia staging, Karnofsky score). On two-way analyses of covariance, HIV infection (independent of MJ) was associated with trends for reduced N-acetyl aspartate (NA) in the parietal white matter and increased choline compounds (CHO) in the basal ganglia. In contrast, MJ (independent of HIV) was associated with decreased basal ganglia NA (-5.5%, p = 0.05), CHO (-10.6%, p = 0.04), and glutamate (-9.5%, p = 0.05), with increased thalamic creatine (+6.1%, p = 0.05). HIV + MJ was associated with normalization of the reduced glutamate in frontal white matter (interaction p = 0.01). After correction for age, education, or mood differences, MJ users had no significant abnormalities on neuropsychological test performance, and HIV subjects only had slower reaction times. These findings suggest chronic MJ use may lead to decreased neuronal and glial metabolites, but may normalize the decreased glutamate in HIV patients.

Traditional Chinese medicine based subgrouping of irritable bowel syndrome patients

Partly from lack of effective conventional therapeutics, patients with irritable bowel syndrome (IBS) turn to complementary and alternative approaches, including Traditional Chinese Medicine (TCM). Key to TCM's approach to IBS is individualized therapies targeted at subgroups. Subgroups represent distinct patterns of dysregulation (e.g. "excess" or "deficiency") identified by both intestinal and extra-intestinal symptoms. Our objective was to identify operational criteria supporting the existence of TCM-based subgroups in IBS and to assess reliability and validity of these criteria. Using TCM principles, items were selected on face validity from conventional questionnaires. TCM practitioners evaluated items for content and face validity. Symptom items and a set of patient cases with item responses were validated by examining patient's pattern of response to items and assessing the consistency with which practitioners diagnosed patients on the spectrum of an "excess" or "deficiency" syndrome. Standard correlation analysis revealed 33 intestinal and extra-intestinal symptom items. There was high degree of practitioner agreement in assessing individual items to particular patterns. External validation by practitioners of cases showed high internal consistency among practitioners (Cronbach's alpha coefficients of 0.91 and 0.87 for excess and deficiency, respectively) and high correlation of average practitioner rating to original questionnaire generated scores (Pearson correlation coefficients of 0.94 and 0.92 for excess and deficiency, respectively). This pilot study provides preliminary support for a methodology to identify novel subgroups of IBS patients related to the TCM classification, which may differ in underlying pathophysiology and treatment responses.

Comprehension and awareness of symptoms in women with dyspepsia

BACKGROUND

Overlapping symptoms of gastro-oesophageal reflux disease and dyspepsia are a problem for physicians and patients.

AIM

This study explored comprehension of dyspepsia symptoms and associated medical terminology among women with symptoms of dyspepsia.

METHODS

The US women aged > or = 18 years with dyspepsia (defined by Rome II criteria) were recruited in two phases, via direct mail, the Internet, clinical investigators and/or gastroenterologists. In phase I, subjects took part in an hour-long telephonic interview comprising open-ended questions relating to symptom frequency/duration, triggers/patterns and severity. During phase II, subjects took part in a 45-min telephonic interview, which explored their understanding of dyspepsia symptoms and their predominant or most bothersome symptom.

RESULTS

Subjects with 'pure' dyspepsia (without overlapping symptoms of gastro-oesophageal reflux disease or irritable bowel syndrome) were sought, but of 777 subjects screened, most were excluded because of gastrointestinal comorbidities (irritable bowel syndrome, gastro-oesophageal reflux disease). Only 85 (11%) subjects had 'pure' dyspepsia of whom 11 withdrew. Of the 74 subjects interviewed, 70% were unfamiliar with the term 'dyspepsia'. Subjects reported several symptoms, including bloating (65%), gas (50%), nausea (41%) and discomfort (36%). Most subjects could distinguish between symptom bothersomeness and severity, and between pain and discomfort. Terms such as 'satisfactory relief', 'central upper abdominal discomfort', 'early satiety' and 'postmeal fullness' were often misunderstood.

CONCLUSIONS

Subjects with 'pure' dyspepsia are rare, because of comorbidities. Dyspepsia-related terminology is often misunderstood by subjects.

A randomised controlled trial assessing the efficacy and safety of repeated tegaserod therapy in women with irritable bowel syndrome with constipation

BACKGROUND

It has been proposed that treatments for irritable bowel syndrome with constipation (IBS-C) should provide rapid symptomatic relief, be intermittent, and effective upon repeated use.

AIMS

To evaluate the efficacy and safety of tegaserod on IBS symptoms, and its impact on quality of life and health economic measures.

PATIENTS

Women (> or = 18 years of age) with IBS-C according to the Rome II criteria.

METHODS

Prospective, double blind, placebo controlled, randomised trial. Women with IBS-C either received tegaserod 6 mg twice daily or placebo for one month. Patients with at least a partial response entered a treatment free interval. Upon symptom recurrence, tegaserod treated patients were re-randomised to tegaserod or placebo for an additional month. Primary efficacy variables were response (overall IBS symptoms and abdominal discomfort/pain) to first and repeated treatment. Analysis was by intention to treat.

RESULTS

2660 patients and 1191 patients were randomised for first and repeated treatment respectively. Tegaserod was superior to placebo for each primary efficacy variable (first treatment: 33.7% v 24.2% responders respectively for relief of IBS symptoms and 31.3% v 22.1% for relief of abdominal discomfort/pain; repeated treatment: 44.9% v 28.7%, and 42.4% v 27.1%, all p < 0.0001). Tegaserod was superior to placebo for every secondary efficacy variable (relief of abdominal discomfort/pain, bloating and constipation; stool frequency and consistency). A response to tegaserod was observed within the first treatment week. Tegaserod produced greater satisfaction, work productivity, and improved quality of life than placebo (p < 0.05).

CONCLUSION

Tegaserod provides rapid and sustained relief of IBS-C symptoms both during first and repeated treatment.

fMRI-acoustic noise alters brain activation during working memory tasks

Scanner noise during functional magnetic resonance imaging (fMRI) may interfere with brain function and change blood oxygenation level dependent (BOLD) signals, a problem that generally worsens at the higher field strengths. Therefore, we studied the effect of increased acoustic noise on fMRI during verbal working memory (WM) processing. The sound pressure level of scanner noise was increased by 12 dBA from "Quiet" to "Loud" echo planar imaging (EPI) scans by utilizing resonant vibration modes of the gradient coil. A WM paradigm with graded levels of task difficulty was used to further access WM load. Increased scanner noise produced increased BOLD responses (percent signal change) bilaterally in the cerebellum, inferior (IFG), medial (medFG), and superior (SFG) frontal, fusiform (FusG), and the lingual (LG) gyri, and decreased BOLD responses bilaterally in the anterior cingulate gyrus (ACG) and the putamen. This finding suggests greater recruitment of attention resources in these brain regions, probably to compensate for interference due to louder scanner noise. Increased working memory load increased the BOLD signals in IFG and the cerebellum, but decreased the BOLD signals in the putamen and the LG. These findings also support the idea that brain function requires additional attention resources under noisier conditions. Load- and acoustic-noise-related changes in BOLD responses correlated negatively in the WM network. This study demonstrates that MR noise affects brain activation pattern. Future comparisons between studies performed under different acoustic conditions (due to differing magnetic field strengths, pulse sequences, or scanner manufacturers) might require knowledge of the sound pressure level of acoustic noise during fMRI.

Sex specific alterations in autonomic function among patients with irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is associated with increased psychological symptoms, early life stressors, and alterations in visceral perception and brain responses to noxious visceral stimuli. The autonomic nervous system (ANS) is a likely mediator for these brain-gut interactions. The few studies directly examining ANS measures have been suggestive of alterations in some IBS patients, but no studies to date have examined the potentially critical variables of sex differences or response to visceral stimulation.

AIMS

(1) To test differences in ANS function during rest and during a visceral stressor (rectosigmoid balloon distension) between IBS patients and healthy control subjects. (2) To examine the role of sex on the autonomic responses of IBS patients.

METHODS

Baseline autonomic measures were evaluated from 130 Rome I positive IBS patients and 55 healthy control subjects. Data were also collected from a subset of 46 IBS patients and 16 healthy control subjects during a sigmoid balloon distension study. Heart rate variability measures of peak power ratio (PPR) and peak power high frequency (PPHF) were analysed to assess sympathetic balance and parasympathetic response, respectively. Peripheral sympathetic response was measured by skin conductance.

RESULTS

IBS patients showed a greater skin conductance response to visceral distension than controls. IBS patients had higher PPR and lower PPHF across conditions. Male IBS patients had higher skin conductance and PPR than females and lower PPHF.

CONCLUSIONS

IBS patients have altered autonomic responsiveness to a visceral stressor, with increased sympathetic and decreased parasympathetic activity. These differences are predominantly seen in males.

Irritable bowel syndrome in the United States: prevalence, symptom patterns and impact

BACKGROUND

The impact of irritable bowel syndrome, a gastrointestinal motility disorder, is underestimated and poorly quantified, as clinicians may see only a minority of sufferers.

AIM

To determine the prevalence, symptom patterns and impact of irritable bowel syndrome in the US.

METHODS

This two-phase community survey used quota sampling and random-digit telephone dialing (screening interview) to identify individuals with medically diagnosed irritable bowel syndrome or individuals not formally diagnosed, but fulfilling irritable bowel syndrome diagnostic criteria (Manning, Rome I or II). Information on irritable bowel syndrome symptoms, general health status, lifestyle and impact of symptoms on individuals' lives was collected using in-depth follow-up interviews. Data were also collected for healthy controls identified in the screening interviews.

RESULTS

The total prevalence of irritable bowel syndrome in 5009 screening interviews was 14.1% (medically diagnosed: 3.3%; undiagnosed, but meeting irritable bowel syndrome criteria: 10.8%). Abdominal pain/discomfort was the most common symptom prompting consultation. Most sufferers (74% medically diagnosed; 63% undiagnosed) reported alternating constipation and diarrhoea. Previously diagnosed gastrointestinal disorders occurred more often in sufferers than non-sufferers. Irritable bowel syndrome sufferers had more days off work (6.4 vs. 3.0) and days in bed, and reduced activities to a greater extent than non-sufferers.

CONCLUSIONS

Most (76.6%) irritable bowel syndrome sufferers in the US are undiagnosed. Irritable bowel syndrome has a substantial impact on sufferers' well-being and health, with considerable socioeconomic consequences.

A multicenter in vivo proton-MRS study of HIV-associated dementia and its relationship to age

OBJECTIVE

Differences in diagnostic criteria and methods have led to mixed results regarding the metabolite pattern of HIV-associated brain injury in relation to neurocognitive impairment. Therefore, a multicenter MRS consortium was formed to evaluate the neurometabolites in HIV patients with or without cognitive impairment.

METHODS

Proton magnetic resonance spectroscopy (MRS) at short-echo time (30 ms) was assessed in the frontal white matter, basal ganglia, and parietal cortex of 100 HIV patients [61 with AIDS dementia complex (ADC) and 39 neuroasymptomatic (NAS)] and 37 seronegative (SN) controls.

RESULTS

Compared to SN, NAS had higher glial marker myoinositol-to-creatine ratio (MI/Cr) in the white matter (multivariate analyses, adjusted P=0.001), while ADC showed further increased MI/Cr in the white matter and basal ganglia (both P<0.001), and increased choline compounds (Cho)/Cr in white matter (P=0.04) and basal ganglia (P<0.001). Compared to NAS, ADC showed a reduction in the neuronal marker N-acetyl compound (NA)/Cr in the frontal white matter (P=0.007). CSF, but not plasma, viral load correlated with MI/Cr and Cho/Cr in white matter and NAA/Cr in parietal cortex. HIV infection and aging had additive effects on Cho/Cr and MI/Cr in the basal ganglia and white matter.

CONCLUSIONS

The results suggest that glial activation occurs during the NAS stages of HIV infection, whereas further inflammatory activity in the basal ganglia and neuronal injury in the white matter is associated with the development of cognitive impairment. Aging may further exacerbate brain metabolites associated with inflammation in HIV patient and thereby increase the risk for cognitive impairment.

Increased frontal white matter diffusion is associated with glial metabolites and psychomotor slowing in HIV

Diffusion-weighted imaging (DWI) measures brain water diffusion that is sensitive to microscopic brain injury. A total of 11 HIV seropositive patients were compared to 14 seronegative subjects using DWI, proton magnetic resonance spectroscopy (1H MRS), and neuropsychological tests. The apparent diffusion coefficient (ADC) was significantly increased in the HIV patients, primarily in the frontal white matter (FWM; +5%, p=0.01). Diffusivity correlated positively with the glial marker myo-inositol (r=0.5, p=0.008) and negatively with cognitive performance (NPZ-8 composite score; r=-0.43, p=0.05). These findings suggest increased brain water diffusion may reflect increased glial activation or inflammation, which in turn, may contribute to the cognitive deficits in HIV patients.

Cortical processing of visceral and somatic stimulation: Differentiating pain intensity from unpleasantness

Visceral and somatic pain perception differs in several aspects: poor localization of visceral pain and the ability of visceral pain to be referred to somatic structures. The perception of pain intensity and affect in visceral and somatic pain syndromes is often different, with visceral pain reported as more unpleasant. To determine whether these behavioral differences are due to differences in the central processing of visceral and somatic pain, non-invasive imaging tools are required to examine the neural correlates of visceral and somatic events when the behavior has been isolated and matched for either unpleasantness or pain intensity. In this study we matched the unpleasantness of somatic and visceral sensations and imaged the neural representation of this perception using functional magnetic resonance imaging in 10 healthy right-handed subjects. Each subject received noxious thermal stimuli to the left foot and midline lower back and balloon distension of the rectum while being scanned. Stimuli were matched to the same unpleasantness rating, producing mild-moderate pain intensity for somatic stimuli but an intensity below the pain threshold for the visceral stimuli. Visceral stimuli induced deactivation of the perigenual cingulate bilaterally with a relatively greater activation of the right anterior insula-i.e. regions encoding affect. Somatic pain induced left dorso-lateral pre-frontal cortex and bilateral inferior parietal cortex activation i.e. regions encoding spatial orientation and assessing perceptual valence of the stimulus. We believe that the observed patterns of activation represent the differences in cortical process of interoceptive (visceral) and exteroceptive (somatic) stimuli when matched for unpleasantness.

Practice-induced changes of brain function during visual attention: a parametric fMRI study at 4 Tesla

A parametric functional MRI (fMRI) study with three levels of task difficulty was performed to determine the effect of practice and attentional load on brain activation during visual attention tasks. Brief practice during repeat fMRI scanning (20 min) did not change performance accuracy or reaction times (RT), but decreased activation bilaterally in the inferior, middle, and superior frontal gyri, superior temporal gyrus, thalamus, and cerebellum. Increased attentional load decreased performance accuracy but not RT, and increased activation bilaterally in the inferior, posterior, and superior parietal cortices, thalamus, cerebellum, and frontal gyri. These changes suggest that practice decreases dependency on thalamus, cerebellum, and the frontal cortices for controlled task processing possibly due to increased efficiency of the attentional network. Since short-term practice-effects in the prefrontal cortex may be similar to attentional load-effects, studies of attentional load need to take practice effects into account.

Review article: epidemiology and quality of life in functional gastrointestinal disorders

The epidemiology and health-related quality of life associated with functional gastrointestinal disorders are reviewed, with particular emphasis on irritable bowel syndrome and functional dyspepsia. The literature supports the significant world-wide prevalence of functional gastrointestinal disorders, including irritable bowel syndrome (IBS), functional dyspepsia and chronic constipation. An increased female prevalence has been demonstrated in most studies in patients with IBS and chronic constipation, but not functional dyspepsia. The female to male ratio appears to be greater in the health care-seeking population than in community populations. However, some differences in the reported general prevalence and gender-related prevalence of functional gastrointestinal disorders may be due to cultural factors and study methodology. A significant health care burden is associated with IBS, with increased out-patient services, abdominal and pelvic surgeries, and gastrointestinal- and non-gastrointestinal-related physician visits and health care costs. Health-related quality of life is impacted significantly in patients with functional gastrointestinal disorders, such as functional dyspepsia and IBS, compared with the general healthy population, as well as patients with other chronic medical conditions, such as gastro-oesophageal reflux disease and asthma. Impaired health-related quality of life has been demonstrated, in particular, in patients with moderate to severe disease seen in referral settings. The health-related quality of life appears to improve in treatment responders, or correlates with symptom improvement, with at least some treatment modalities studied in functional gastrointestinal disorders, but further studies are needed. Predictors of health-related quality of life in patients with functional gastrointestinal disorders include psychosocial factors, such as early adverse life events, and symptoms related to visceral perception, e.g. pain and chronic stress. The presence of extra-intestinal symptoms appears to have a major if not greater impact on health care visits, excess health care costs and health-related quality of life in patients with functional gastrointestinal disorders.

Altered neurometabolite development in HIV-infected children: correlation with neuropsychological tests

BACKGROUND

HIV-infected children have abnormal cerebral metabolites, measured by proton MR spectroscopy ((1)H-MRS), but how these abnormalities relate to brain function is unclear.

METHODS

Metabolite concentrations in five brain regions of 20 HIV-infected and 13 control children were measured, and these findings were correlated with age, log(10) plasma viral load, CD4 count, and neuropsychological scores.

RESULTS

Compared with control subjects, HIV patients had decreased choline concentration [Cho] in left frontal white matter (LFW) (-12%; p = 0.04); those with high viral load (>5,000 HIV RNA copies/mL) had decreased right basal ganglia (RBG) [Cho] (-15%; p = 0.005), and [Cr] (-13%; p = 0.02). Patients with high viral load also had higher [Cho] in the midfrontal gray matter (MFG) (+25%; p = 0.002) and lower myo-inositol [Ins] in the RBG (-18%; p = 0.04) than patients with low HIV viral load. N-Acetyl aspartate concentration ([NAA]) correlated with age in right frontal white matter (RFW) (r = 0.59, p = 0.04), LFW (r = 0.66, p = 0.02), and right hippocampus (RHIP) (r = 0.69, p = 0.02) only in control subjects. In contrast, [Ins] correlated with age in both RFW and LFW (r = 0.71, p = 0.0006; r = 0.65, p = 0.006) only in the HIV patients. Log(10) plasma viral load correlated positively with [Ins] in RFW (r = 0.54, p = 0.02) and [Cho] in MFG (r = 0.49, p = 0.04). Compared with control subjects, HIV patients had poorer spatial memory (p = 0.045) and delayed spatial memory correlated with [Cho] in RHIP (r = 0.68, p = 0.02).

CONCLUSIONS

These data suggest that normal brain development may be affected in children infected with HIV at birth, particularly evidenced by the lack of age-related increases in the neuronal marker [NAA]. Early, aggressive treatment of infants with HIV before development of encephalopathy is warranted.

Taurine protected myocardial mitochondria injury induced by hyperhomocysteinemia in rats

Taurine can protect against cardiovascular diseases, whereas elevated levels of plasma homocysteine are associated with atherosclerotic and thromboembolic cardiovascular diseases. To illustrate the effects of taurine on hyperhomocysteinemia, we observed the myocardial mitochondria dysfunction in the rats with hyperhomocysteinemia induced by diet methionine loading, and the therapeutic effect of taurine. A methionine diet increased plasma homocysteine concentration (133.51 +/- 27.91 micromol/L vs 12.31 +/- 2.58 micromol/L in control, P < 0.01), stimulated the production of reactive oxygen species (ROS) in the myocardial mitochondria, and inhibited the activities of mitochondrial Mn-superoxide dismutase and catalase. The 45Ca uptake and Ca2+-ATPase activity in the myocardial mitochondria were significantly lowered in rats with hyperhomocysteinemia. Taurine supplements effectively attenuated the hyperhomocysteinemia-induced ROS production and inhibition of Mn-superoxide dismutase and catalase activities in the myocardial mitochondria, and increased its 45Ca uptake and Ca2+-ATPase activity. Thus, taurine antagonizes the oxidative stress injury in the myocardial mitochondria induced by the hyperhomocysteinemia.

The Visceral Sensitivity Index: development and validation of a gastrointestinal symptom-specific anxiety scale

BACKGROUND

Anxiety related to gastrointestinal sensations, symptoms or the contexts in which these may occur is thought to play a significant role in the pathophysiology as well as in the health outcomes of patients with irritable bowel syndrome.

AIM

To develop a valid and reliable psychometric instrument that measures gastrointestinal symptom-specific anxiety.

METHODS

External and internal expert panels as well as a patient focus group evaluated a large pool of potential item stems gathered from the psychological and gastrointestinal literature. Potential scale items were then administered to 96 patients diagnosed with irritable bowel syndrome along with a set of validating questionnaires. Final item selection was based upon rigorous empirical criteria and the psychometric properties of the final scale were examined.

RESULTS

A final unidimensional 15-item scale, the Visceral Sensitivity Index, demonstrated excellent reliability as well as good content, convergent, divergent and predictive validity.

CONCLUSIONS

The findings suggest that the Visceral Sensitivity Index is a reliable, valid measure of gastrointestinal symptom-specific anxiety that may be useful for clinical assessment, treatment outcome studies, and mechanistic studies of the role of symptom-related anxiety in patients with irritable bowel syndrome.

Novel strategy for identification of candidate cytotoxic T-cell epitopes from human preproinsulin

We describe a strategy for identifying ligands of human leukocyte antigen (HLA) class I molecules based on a peptide library-mediated in vitro assembly of recombinant class I molecules. We established a microscale class I assembly assay and used a capture ELISA to quantify the assembled HLA-peptide complexes. The identity of the bound ligands was then deduced by mass spectrometry. In this method, HLA complexes assembled in vitro in the presence of components of a mixture of peptides were immunoprecipitated and the bound peptide(s) identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. This process of epitope extraction is robust and can be used with complex mixtures containing in excess of 300 candidate ligands. A library of overlapping peptides representing all potential octamers, nonamers and decamers from human preproinsulin was synthesized using unique library chemistry. Peptides from the library were used to initiate assembly of recombinant HLA-B8, HLA-B15 and HLA-A2, facilitating the identification of candidate T-cell epitopes from preproinsulin.

Using chaotic interrogation and attractor nonlinear cross-prediction error to detect fastener preload loss in an aluminum frame

Structural health monitoring is an important field concerned with assessing the current state (or "health") of a structural system or component with regard to its ability to perform its intended function appropriately. One approach to this problem is identifying appropriate features obtained from time series vibration responses of the structure that change as structural degradation occurs. In this work, we present a novel technique adapted from the nonlinear time series prediction community whereby the structure is excited by an applied chaotic waveform, and predictive maps built between structural response attractors are used as the feature space. The structural response is measured at several points on the structure, and pairs of attractors are used to predict each other. As the dynamics of the structure change due to damage, the prediction error rises. This approach is applied to detecting the preload loss in a bolted joint in an aluminum frame structure.

Methamphetamine and AIDS: 1HMRS studies in a feline model of human disease

Potential interactions between psychostimulant drugs and infection with feline immunodeficiency virus (FIV) on brain metabolism were evaluated. Four groups of cats were studied: control, FIV positive, methamphetamine (MA) exposed, and FIV positive plus MA exposed. Frontal gray matter, frontal white matter, and caudate brain extracts were studied with proton magnetic resonance spectroscopy (1HMRS). In the frontal white matter, FIV-infected cats showed decreases in creatine and choline, while MA-treated cats had elevated gamma-aminobutyric acid (GABA). The decreased glutamate in FIV cats normalized with MA exposure. FIV and MA both affect brain metabolites individually and combined. 1HMRS is useful for evaluating the effects of FIV and drug abuse in the brain.

Androgens modulate beta-amyloid levels in male rat brain

As a normal consequence of aging, men experience a significant decline in androgen levels. Although the neural consequences of age-related androgen depletion remain unclear, recent evidence suggests a link between low androgen levels and the development of Alzheimer's disease (AD). Here, we test the hypothesis that androgens act as endogenous modulators of beta-amyloid protein (Abeta) levels. To investigate this possibility, brain and plasma levels of Abeta were measured in male rats with varying hormonal conditions. Depletion of endogenous sex steroid hormones via gonadectomy (GDX) resulted in increased brain levels of Abeta in comparison to gonadally intact male rats. This GDX-induced increase in Abeta levels was reversed by DHT supplementation, demonstrating a functional role for androgens in modulating brain levels of Abeta. These findings suggest that age-related androgen depletion may result in accumulation of Abeta in the male brain and thereby act as a risk factor for the development of AD.

Anti-hyperalgesic effect of octreotide in patients with irritable bowel syndrome

BACKGROUND

Octreotide has been found to be beneficial in the treatment of chronic pain, although the mechanisms underlying its therapeutic effect are incompletely understood.

AIMS

To assess the effect of octreotide on perceptual responses to rectal distension in irritable bowel syndrome patients and healthy controls at baseline and following the experimental induction of rectal hyperalgesia.

METHODS

In study 1, rectal perception thresholds for discomfort were determined in seven irritable bowel syndrome patients and eight healthy controls on three separate days using a computer-controlled barostat. Subjects received saline, low-dose and high-dose octreotide in a random double-blind fashion. In study 2, perceptual responses to rectal distension were obtained in nine irritable bowel syndrome patients and seven controls before and after repetitive high-pressure mechanical sigmoid stimulation.

RESULTS

Octreotide increased the discomfort thresholds in irritable bowel syndrome patients, but not in controls, without changing rectal compliance. Repetitive sigmoid stimulation resulted in decreased rectal discomfort thresholds in the patient group only. In irritable bowel syndrome patients, octreotide prevented the sensitizing effect of repetitive sigmoid stimulation on rectal discomfort thresholds.

CONCLUSIONS

Octreotide effectively increased discomfort thresholds in irritable bowel syndrome patients, but not in controls, at baseline and during experimentally induced rectal hyperalgesia. These findings suggest that octreotide exerts primarily an anti-hyperalgesic rather than analgesic effect on visceral perception.

Robotic surgery: identifying the learning curve through objective measurement of skill

BACKGROUND

The incorporation of new devices into surgical practice often requires that surgeons acquire and master new skills. We studied the learning curve for intracorporeal knot tying in robotic surgery.

METHODS

We developed an objective scoring system to evaluate knot tying and tested eight attending surgeons during 3 weeks of training on a surgical robot. Each performed intracorporeal knot tying tasks both before and after robotic skills training. These performances were compared to their laparoscopic knots and analyzed to determine and define skill improvement.

RESULTS

Baseline laparoscopic knot completion took 140 sec (range, 47-432), with a mean composite score of 77 (100 possible), whereas robotic knot tying took 390 sec, with a mean composite score of 40. After initial robotic training, times decreased by 65% to 139 sec and scores increased to 71. With more training, completion times and composite scores were improved and errors were reduced.

CONCLUSION

Like any new technology, surgical robotics requires dedicated training to achieve mastery. Initially, even experienced laparoscopists may register an inferior performance. However, after adequate training, surgeons can exceed their laparoscopic performance, completing intracorporeal knots better and faster using robotics.

Increased glial metabolites predict increased working memory network activation in HIV brain injury

Deficits in attention and working memory are common in human immuno deficiency virus type 1 (HIV-1)-infected patients, but the pathophysiology of these deficits is poorly understood. Modern neuroimaging techniques, such as proton magnetic resonance spectroscopy ((1)H MRS) and functional MRI (fMRI), can assess some of the processes underlying HIV brain injury. To evaluate the model that attentional deficits in early HIV brain disease are related to brain inflammation, (1)H MRS and fMRI were performed in 14 HIV-positive subjects [acquired immunodeficiency syndrome (AIDS) dementia complex stage 1 or less]. Increasing attentional load on three working memory tasks was assessed with fMRI, and the concentrations of brain metabolites were measured with (1)H MRS in the frontal gray and white matter, and basal ganglia. Metabolite concentrations were correlated with fMRI blood oxygenation level-dependent (BOLD) signals, using a random-effects linear regression model in SPM99. Several positive correlations were observed between the BOLD signal strength in the working memory network (posterior parietal cortex and lateral prefrontal cortex) and the concentrations of frontal white matter and basal ganglia metabolites that are predominant in glial cells (choline-containing compounds, myo-inositol, and total creatine). In contrast, BOLD signals in the working memory network were not correlated with the concentration of N-acetyl compounds, which are markers of neuronal viability, or with metabolite concentrations in the frontal gray matter. These findings are consistent with previous results that mild HIV brain injury is associated with increased glial activation without major involvement of neuronal abnormalities. We propose that the inflammatory glial abnormalities reduce the efficiency of neural processing, and necessitate compensatory increases in attention in patients, and associated BOLD signals, to perform a given task. The same mechanism may also contribute to cognitive dysfunction in other brain diseases that involve inflammation.

Topotecan in the treatment of acquired immunodeficiency syndrome-related progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) affects about 1 in 20 individuals with the acquired immunodeficiency syndrome (AIDS) and has been associated with poor survival. This report describes the results of a phase II clinical trial using the drug topotecan, a semisynthetic analogue of camptothecan, administered to a cohort of subjects with AIDS-related PML. Data were evaluated on 11 of 12 subjects enrolled in the study. Three responded to therapy. Additionally, one patient was treated off-protocol and showed a response to treatment. Progression occurred after the first course; however, a partial response was noted after five courses. One study patient died from accidental overdose of topotecan. Overall, responders had higher pretreatment Karnofsky and lower Kurtzke expanded disability status scale scores than nonresponders. The most frequent toxicities were hematologic (anemia, neutropenia, and thrombocytopenia). Five patients had dose delays; all delays were due to hematologic adverse events. This study demonstrates that topotecan treatment may be associated with decreased lesion size and prolonged survival from the infection. Because of the small number of subjects in the study, further studies are required to evaluate the efficacy of topotecan in treating this disease.

Improving accuracy in identifying the gastroesophageal junction during laparoscopic antireflux surgery

BACKGROUND

Proper construction of an effective fundoplication to control reflux depends on accurate identification of the gastroesophageal junction (GEJ). In laparoscopic surgery, the accuracy of this GEJ determination is unknown.

METHODS

In 40 consecutive laparoscopic antireflux procedures, the GEJ location was determined independently by endoscopy and laparoscopy, and the differences were measured. After this was completed, endoscopic examination of the fundoplication was performed.

RESULTS

The "laparoscopic" GEJ was identified within 1 cm of the "endoscopic" GEJ in 36 of 40 (90%) patients. In four patients, this difference was greater and the GEJ always higher than determined by laparoscopy. These patients had greater acid exposure and esophageal injury. On two occasions, the fundoplication was reconstructed on the basis of endoscopic findings.

CONCLUSIONS

With laparoscopy, the surgeon can accurately determine the GEJ location in most patients. In approximately 10%, the GEJ is actually higher than the surgeon believes, and the fundoplication may be created lower than intended. Intraoperative endoscopy helps to identify the GEJ location and evaluate the wrap once completed.

Real-time PCR assay for quantitative mismatch detection

We describe here a quantitative real-time PCR assay for the detection of single-base-pair differences that does not require fluorescently labeled gene-specific probes or complicated primer combinations. Following PCR or RT-PCR of a gene segment that may contain allele-specific differences, 100 pg amplified product are used for a real-time PCR with allele-specific primers and SYBR Green. The use of HEPES buffer at a pH of 6.95 together with AmpliTaq DNA polymerase results in a threshold difference between the correct template and the mismatched template of as many as 20 cycles, depending on the mismatch. Correct matches can be detected in an excess of mismatched template at least at the 0.01 level for the six primer-template matches versus mismatches tested: GC vs. A.C, AT vs. G.T, GC vs. C.C, GC vs. G.G, AT vs. C.T, and GC vs. G.A. Because the initial amplification is separate from real-time detection, conditions can be independently optimized for each step, making the assay particularly suitable for the detection of allele-specific expression in single cells.

Abnormal brain activation on functional MRI in cognitively asymptomatic HIV patients

BACKGROUND/OBJECTIVES

A previous fMRI study demonstrated increased brain activation during working memory tasks in patients with HIV with mild dementia. The current study aims to determine whether patients who are HIV-1 positive and have normal cognitive function also show increased brain activation on fMRI.

METHODS

Blood oxygenation level-dependent (BOLD) fMRI was performed in 10 patients with HIV (CD <500) and 10 age-, sex-, education-, and handedness-matched seronegative subjects. Each subject performed a battery of neuropsychological tests and fMRI with three tasks (0-back, 1-back, and 2-back) that required different levels of attention for working memory.

RESULTS

Compared with control subjects, patients with HIV showed greater magnitude of brain activation (BOLD signal intensity changes, p <or= 0.001) in the lateral prefrontal cortex, with normal performance during fMRI and on a battery of neuropsychological tests. The patients with HIV also showed increased activated brain volume in the lateral prefrontal cortex (p = 0.007) but not in other activated regions, including the posterior parietal cortex, supplementary motor area, thalamus, caudate, and occipital cortex. The increase in activated brain volume was independent of task difficulty.

CONCLUSION

Increased brain activation in subjects who are positive for HIV precedes clinical signs or deficits on cognitive tests. Early injury to the neural substrate may necessitate increased usage of brain reserve to maintain normal cognitive function. BOLD fMRI appears to be more sensitive than clinical and neuropsychological evaluations for detecting early HIV-associated brain injury.

The effect of the 5-HT3 receptor antagonist, alosetron, on brain responses to visceral stimulation in irritable bowel syndrome patients

AIM

To conduct a placebo-controlled functional brain imaging study to assess the effect of the 5-hydroxytryptamine-3 receptor antagonist, alosetron, on irritable bowel syndrome symptoms, regional brain activation by rectosigmoid distension and associated perceptual and emotional responses.

METHODS

Fifty-two non-constipated irritable bowel syndrome patients (28 female) were enrolled in a randomized, placebo-controlled trial with alosetron (1-4 mg b.d.). Thirty-seven patients completed both brain scans following randomization. Rectosigmoid stimulation was performed with a computer-controlled barostat. Changes in regional cerebral blood flow were assessed using H215O positron emission tomography. Stimulus ratings and changes in gastrointestinal symptoms were assessed using verbal descriptor scales.

RESULTS

Alosetron, but not placebo, treatment was associated with a decrease in symptom ratings, and reductions in emotional stimulus ratings. Compared to baseline, alosetron treatment was associated with reduced regional cerebral blood flow in bilateral frontotemporal and various limbic structures, including the amygdala. Compared to placebo, decreases in activity of the amygdala, ventral striatum, hypothalamus and infragenual cingulate gyrus were significantly greater after alosetron.

CONCLUSIONS

In non-constipated irritable bowel syndrome patients, 3 weeks of treatment with a 5-hydroxytryptamine-3 receptor antagonist decreases brain activity in response to unanticipated, anticipated and delivered aversive rectal stimuli in structures of the emotional motor system, and this is associated with a decrease in gastrointestinal symptoms.

In vivo production of interferon beta by human Tenon's fibroblasts; a possible mediator for the development of chronic conjunctival inflammation

BACKGROUND

Chronic inflammation may develop from failure of the immune system to deactivate itself during resolution of the wound healing response, and is recognised as a major risk factor for trabeculectomy failure. Fibroblast/T cell interactions may contribute to aggressive scarring. Our previous research showed that in vitro human Tenon's fibroblast produced interferon beta was responsible for preventing T cell apoptosis, suggesting that this interaction could contribute to the development of chronic inflammation.

METHODS

Immunohistological techniques were used to investigate the in vivo components of this particular fibroblast/T cell interaction in conjunctival biopsies from glaucoma patients undergoing filtration surgery.

RESULTS

Fibroblast produced interferon beta and T lymphocytes were identified in human conjunctiva.

CONCLUSION

The components of fibroblast mediated prevention of T cell apoptosis were identified in vivo, suggesting that the development of this interaction is possible and that it may contribute to the development of chronic inflammation and excessive scarring.

Basic pathophysiologic mechanisms in irritable bowel syndrome

Converging evidence supports the concept that the irritable bowel syndrome (IBS) symptom complex results from altered regulation of gastrointestinal motility and epithelial function, as well as an altered perception of visceral events. Despite similar symptoms, there is likely heterogeneity of underlying dysfunction and pathogenesis in different subgroups of IBS patients: the syndrome may be produced by primary alterations in the central nervous system (CNS; top down model), or by primary alterations in the periphery (bottom up model), or by a combination of both. One plausible mechanism by which alterations in the CNS result in symptoms, is the enhanced responsiveness of central stress/emotion circuits. The physiological effects of psychological and physical stressors on gut function and brain-gut interactions are mediated by outputs of the emotional motor system in terms of autonomic, neuroendocrine, attentional and pain modulatory responses. IBS patients show an enhanced responsiveness of this system manifesting in altered modulation of gastrointestinal motility, secretion, immune function and in alterations in the perceptual and emotional response to visceral events.