Functional foods and probiotics: time for gastroenterologists to embrace the concept.
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Biomedical subjects
Publications and source records attributed to J McCarthy.
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As our ability to recognise and diagnose human disease caused by helminth parasites has improved, so our understanding of the epidemiology and clinical manifestations of these diseases has improved. Humans can develop patent infection with a wide range of helminth parasites, whose natural host is another vertebrate. Rather than focusing on a comprehensive review of zoonotic helminth infections, this review describes in detail examples of zoonotic helminth infections that have newly appeared in human populations, or have existed but are increasing in incidence or geographic range. Examples include intestinal capillariasis, anisakidosis, eosinophilic enteritis, oesophagostomiasis and gnathostomiasis. Potential reasons for the emergence of these infections, including changes in social, dietary or cultural mores, environmental changes, and the improved recognition of heretofore neglected infections often coupled with an improved ability to diagnose infection are discussed.
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The molecular machinery behind lysosome biogenesis and the maintenance of the perinuclear aggregate of late endocytic structures is not well understood. A likely candidate for being part of this machinery is the small GTPase Rab7, but it is unclear whether this protein is associated with lysosomes or plays any role in the regulation of the perinuclear lysosome compartment. Previously, Rab7 has mainly been implicated in transport from early to late endosomes. We have now used a new approach to analyze the role of Rab7: transient expression of Enhanced Green Fluorescent Protein (EGFP)-tagged Rab7 wt and mutant proteins in HeLa cells. EGFP-Rab7 wt was associated with late endocytic structures, mainly lysosomes, which aggregated and fused in the perinuclear region. The size of the individual lysosomes as well as the degree of perinuclear aggregation increased with the expression levels of EGFP-Rab7 wt and, more dramatically, the active EGFP-Rab7Q67L mutant. In contrast, upon expression of the dominant-negative mutants EGFP-Rab7T22N and EGFP-Rab7N125I, which localized mainly to the cytosol, the perinuclear lysosome aggregate disappeared and lysosomes, identified by colocalization of cathepsin D and lysosome-associated membrane protein-1, became dispersed throughout the cytoplasm, they were inaccessible to endocytosed molecules such as low-density lipoprotein, and their acidity was strongly reduced, as determined by decreased accumulation of the acidotropic probe LysoTracker Red. In contrast, early endosomes associated with Rab5 and the transferrin receptor, late endosomes enriched in the cation-independent mannose 6-phosphate receptor, and the trans-Golgi network, identified by its enrichment in TGN-38, were unchanged. These data demonstrate for the first time that Rab7, controlling aggregation and fusion of late endocytic structures/lysosomes, is essential for maintenance of the perinuclear lysosome compartment.
IMPLICATIONS: We report the successful use of the laryngeal mask airway for percutaneous endoscopic gastrostomy in an adult patient with a known difficult airway and severe cerebral palsy.
Autosomal dominant periodic fever syndromes are characterized by unexplained episodes of fever and severe localized inflammation. In seven affected families, we found six different missense mutations of the 55 kDa tumor necrosis factor receptor (TNFR1), five of which disrupt conserved extracellular disulfide bonds. Soluble plasma TNFR1 levels in patients were approximately half normal. Leukocytes bearing a C52F mutation showed increased membrane TNFR1 and reduced receptor cleavage following stimulation. We propose that the autoinflammatory phenotype results from impaired downregulation of membrane TNFR1 and diminished shedding of potentially antagonistic soluble receptor. TNFR1-associated periodic syndromes (TRAPS) establish an important class of mutations in TNF receptors. Detailed analysis of one such mutation suggests impaired cytokine receptor clearance as a novel mechanism of disease.
PURPOSE: Two forms of autosomal-dominant lattice corneal dystrophy (LCD), types I and IIIA, have previously been shown to be caused by different mutations within the transforming growth factor, beta-induced (TGFBI) gene. A clinical and molecular analysis of three unrelated kindreds with a clinically distinct late-onset LCD was undertaken to determine whether this phenotype is also caused by mutations within the TGFBI gene. DESIGN: Experimental study. PARTICIPANTS: Thirty-two members of three kindreds with corneal dystrophy. DNA from 100 normal control subjects was used as a control population. METHODS: Members of three kindreds with LCD were examined clinically, and blood samples were taken for DNA analysis. Mutation analysis was undertaken on all individuals for the coding region of the TGFBI gene by means of polymerase chain reaction (PCR) followed by single-stranded conformation polymorphism/heteroduplex analysis, subcloning, and sequencing. MAIN OUTCOME MEASURES: Detection of mutations within the TGFBI gene. RESULTS: Clinical examination revealed a form of LCD that was bilateral in all but one case, with onset around the fourth to fifth decade. The majority of cases showed significant asymmetry, and in one case there was evidence of onset directly after minor superficial corneal trauma. Molecular analysis in all families demonstrated sequence changes within exon 14 of the TGFBI gene on chromosome 5q31, at codon 622 in family 3, and at codon 626 in families 1 and 2, which are presumed to be responsible for the disease. CONCLUSIONS: Previously, a late-onset form of LCD, termed IIIA, was shown to be caused by a P501T mutation in exon 11 of TGFBI. The authors present the first description of mutations in exon 14 of TGFBI causing an LCD, also of late onset. Although the condition presented is morphologically and histopathologically typical of an isolated lattice dystrophy, the age of onset and clinical course is not typical of type I, III, or IIIA lattice dystrophy. This, in conjunction with recent developments in our understanding of the molecular genetics of these disorders, calls into question the usefulness and validity of the current classification of the isolated lattice dystrophies.
Clostridium difficile is a common cause of antibiotic-associated diarrhoea, but it rarely causes extra-colonic disease. An 83-year-old woman who developed culture-positive C. difficile-associated diarrhoea following pneumonia and a total hip replacement was treated successfully with oral metronidazole therapy. She was readmitted 12 months later for revision of the hip prosthesis because of increasing pain. At surgery an abscess associated with the prosthesis was discovered. Culture of the pus grew C. difficile. When the surgical isolate and the cryopreserved faecal isolates were compared using Pulsed Field Gel Electrophoresis (PFGE), an identical banding pattern was observed. This case extends the clinical spectrum of C. difficile infection by documenting a prolonged interval between the initial infection, and diagnosis of the prosthetic joint infection. The importance of molecular typing to show strain relatedness is demonstrated.
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The antibody responses of 8 cattle experimentally infected with Onchocerca ochengi to 18 recombinant O. volvulus antigens were measured by ELISA. In addition to establishing antigenic cross-reactivity between the species, the dynamics of antigen-specific responses were examined to assess how the recognition of the antigens compared to the known stage-specificity of expression. Six cattle responded to all of the antigens and 2 animals responded to all but 1. The dynamics of the recognition of 4 antigens (B20, MOv-2, MOv-14 and OvNHR2 02E1) were characterized by rapid seroconversion following infection. Antibody levels to 2 antigens (Ov7 and OvALT-1) increased gradually over the course of infection. Antibody levels to 4 antigens (OvTPX-2, OvL3Chitinase, Ov103 and Ov9m) reached maximum levels coincident with the onset of patency. The levels to 3 antigens (OvProalf C50, OvAldolase, Ov39) varied little over the course of infection. Responses to antigens with functional similarities (OvSOD1, OvSOD2 and OvSOD3 or OvGST1 and OvGST2) showed comparable temporal profiles. This study demonstrates the high degree of immunological cross-reactivity between the antigens of O. volvulus and O. ochengi. The immunogenicity of antigens varied over the course of infection in an antigen-specific manner, which not always reflected developmentally regulated expression of the corresponding gene, possibly owing to cross-reactive epitopes on distinct parasite products.
The majority of clinically used inotropes act by increasing cytosolic calcium levels, which may hypothetically worsen reperfusion stunning and provoke arrhythmias. We tested the hypothesis that the calcium sensitizer levosimendan (levo) given during ischemia alone or ischemia and reperfusion would improve reperfusion function without promoting arrhythmias. The Langendorff-perfused guinea pig heart, subjected to 40-min low-flow ischemia (0.4 ml/min) with or without levo (10-300 nM) given during ischemia or ischemia/reperfusion was used. Left ventricular developed pressure (LVDP) was used as an index of mechanical function. The effect of levo (300 nM) or dobutamine (0.1 microM) on the incidence of ischemia/reperfusion arrhythmias was also investigated. Control hearts (vehicle-perfused) had LVDPs of 69.4 +/- 2.1 mm Hg whereas hearts treated with levo during ischemia and reperfusion (300 nM) had LVDPs of 104.5 +/- 2.7 mm Hg (p <.05). Hearts treated with levo during ischemia alone (10 nM) had reperfusion LVDPs of 95.8 +/- 4.2 mm Hg (p <.05) after 30-min reperfusion. Hearts treated with both levo and 10 microM glibenclamide (K(ATP) channel blocker) during ischemia had reperfusion LVDPs of 73.4 +/- 4.3 mm Hg after 30-min reperfusion. Of control hearts, 25% developed reperfusion ventricular tachycardia but not ventricular fibrillation. Levo-treated hearts had no ischemia/reperfusion arrhythmias whereas 83% (p <.05 versus control) of dobutamine-treated hearts developed ventricular tachycardia and 33% (p <.05 versus levo) developed reperfusion ventricular fibrillation. Levo improved reperfusion function without promoting arrhythmias in this model. This was possibly achieved by opening the K(ATP) channels during ischemia and sensitizing myocardial contractile apparatus instead of elevating cytosolic calcium levels in reperfused hearts.
OBJECTIVES: We tested whether mibefradil, a selective T-type calcium channel blocking agent, could differentially inhibit experimental ventricular arrhythmogenesis more than contractility during acute regional ischemia and reperfusion compared with that during L-channel blockade by verapamil. BACKGROUND: T-type calcium channels are found in nodal and conduction tissue and in vascular smooth muscle, but in much lower density in contractile myocardium. The potential role of mibefradil in ventricular arrhythmogenesis remains unclear. METHODS: Mibefradil (Ro 40-5967, 1 mg/kg body weight intravenously [i.v.]) was given as a bolus 30 min before anterior descending coronary artery ligation, followed by 2 mg/kg per h i.v. during 20 min of ischemia and 25 min of reperfusion in open chest pigs. In a second group, mibefradil was given in a dose twice as high. A third group received verapamil (0.3 mg/kg i.v.), followed by an infusion of 0.6 mg/kg per h. RESULTS: During the ischemic period, the low (clinically relevant) dose of mibefradil prevented the fall of the ventricular fibrillation threshold, without depressing the maximal rate of pressure development of the left ventricle (LVmax dP/dt). This low dose increased left ventricular blood flow, whereas peripheral arterial pressure remained unchanged. The higher dose of both mibefradil and verapamil was antiarrhythmic during ischemia, at the cost of depressed contractile activity. During reperfusion, only the higher dose of mibefradil and verapamil was antiarrhythmic but both depressed contractile activity. CONCLUSIONS: Mibefradil is antiarrhythmic, without inotropic compromise. Speculatively, both T-type and L-type calcium channel blockade are involved in these effects.
OBJECTIVE: To address the unmet need for glasses encountered in an urban school setting by developing and implementing a school-based, cost-effective program that provides appropriate spectacle correction to needy children. METHODS: A total of 5851 students 9 to 15 years of age in 4 middle schools in northern Manhattan were screened for vision. Those with vision worse than 20/40 were examined, given glasses if appropriate, or referred for additional evaluation. RESULTS: Of the 5851 children screened, 1614 (28%) had a failing result, with visual acuity less than 20/40 in the worse eye. Of this group, 1082 were given glasses that were assembled at the school within 1 hour of testing. Ten percent of the group that required glasses already had them, and the remaining were referred for a complete ophthalmic examination that was completed in 58 cases. Only 14 of these had vision loss unrelated to refractive error. CONCLUSIONS: The program successfully treated 88.3% of the children within the school who needed glasses. Given that only 10% of children who needed glasses had them, it indicates a huge need to provide glasses to at least a million children in this age group in the United States.
The combination of a calcium antagonist with an angiotensin-converting enzyme (ACE) inhibitor is increasingly used in the therapy of hypertension, but there are no experimental data supporting the use of this combination in acute myocardial ischemia and reperfusion. We tested the effects of oral pretreatment in a pig model, paying special attention to arrhythmias and adverse hemodynamic effects. Pigs received verapamil 240 mg + trandolapril 4 mg, verapamil 240 mg, or placebo orally once daily for 10 days, after which a coronary artery was ligated for 20 minutes and then allowed to reperfuse. The ventricular fibrillation threshold (VFT) was measured during ischemia to assess the vulnerability of the heart to ventricular fibrillation, whereas spontaneous tachyarrhythmias were monitored during reperfusion. Regional left ventricular (LV) blood flow was measured with radioactive microspheres. During the ischemic period, both the combination of verapamil plus trandolapril, and verapamil alone, prevented a fall in the VFT, indicating antiarrhythmic activity. The combination maintained LV contractile activity and cardiac output (CO) at preligation levels, whereas verapamil alone decreased cardiac output. During reperfusion, verapamil plus trandolapril prevented spontaneous ventricular tachyarrhythmias and increased blood flow in the reperfused zone. In contrast, verapamil was not antiarrhythmic and decreased CO. Thus the addition of the ACE inhibitor trandolapril to the calcium antagonist verapamil resulted in antiarrhythmic activity during ischemia and reperfusion, and produced a better hemodynamic profile.
1. The functional role of the nitric oxide (NO)/guanosine 3':5'-cyclic monophosphate (cyclic GMP) pathway in experimental myocardial ischaemia and reperfusion was studied in rat isolated hearts. 2. Rat isolated hearts were perfused at constant pressure with Krebs-Henseleit buffer for 25 min (baseline), then made ischaemic by reducing coronary flow to 0.2 ml min(-1) for 25 or 40 min, and reperfused at constant pressure for 25 min. Drugs inhibiting or stimulating the NO/cyclic GMP pathway were infused during the ischaemic phase only. Ischaemic contracture, myocardial cyclic GMP and cyclic AMP levels during ischaemia, and recovery of reperfusion mechanical function were monitored. 3. At baseline, heart rate was 287+/-12 beats min(-1), coronary flow was 12.8+/-0.6 ml min(-1), left ventricular developed pressure (LVDevP) was 105+/-4 mmHg and left ventricular end-diastolic pressure 4.6+/-0.2 mmHg in vehicle-treated hearts (control; n=12). Baseline values were similar in all treatment groups (P>0.05). 4. In normoxic perfused hearts, 1 microM N(G)-nitro-L-arginine (L-NOARG) significantly reduced coronary flow from 13.5+/-0.2 to 12.1+/-0.1 ml min(-1) (10%) and LVDevP from 97+/-1 to 92+/-1 mmHg (5%; P<0.05, n=5). 5. Ischaemic contracture was 46+/-2 mmHg, i.e. 44% of LVDevP in control hearts (n=12), unaffected by low concentrations of nitroprusside (1 and 10 microM) but reduced to approximately 30 mmHg (approximately 25%) at higher concentrations (100 or 1000 microM; P<0.05 vs control, n=6). Conversely, the NO synthase inhibitor L-NOARG reduced contracture at 1 microM to 26+/-3 mmHg (23%), but increased it to 63+/-4 mmHg (59%) at 1000 microM (n=6). Dobutamine (10 microM) exacerbated ischaemic contracture (81+/-3 mmHg; n = 7) and the cyclic GMP analogue Sp-8-(4-p-chlorophenylthio)-3',5'-monophosphorothioate (Sp-8-pCPT-cGMPS; 10 microM) blocked this effect (63+/-11 mmHg; P<0.05 vs dobutamine alone, n=5). 6. At the end of reperfusion, LVDevP was 58+/-5 mmHg, i.e. 55% of pre-ischaemic value in control hearts, significantly increased to approximately 80% by high concentrations of nitroprusside (100 or 1000 microM) or L-NOARG at 1 microM, while a high concentration of L-NOARG (1000 microM) reduced LVDevP to approximately 35% (P<0.05 vs control; n=6). 7. Ischaemia increased tissue cyclic GMP levels 1.8 fold in control hearts (P<0.05; n=12); nitroprusside at 1 microM had no sustained effect, but increased cyclic GMP approximately 6 fold at 1000 microM; L-NOARG (1 or 1000 microM) was without effect (n=6). Nitroprusside (1 or 1000 microM) marginally increased cyclic AMP levels whereas NO synthase inhibitors had no effect (n=6). 8. In conclusion, the cardioprotective effect of NO donors, but not of low concentrations of NO synthase inhibitors may be due to their ability to elevate cyclic GMP levels. Because myocardial cyclic GMP levels were not affected by low concentrations of NO synthase inhibitors, their beneficial effect on ischaemic and reperfusion function is probably not accompanied by reduced formation of NO and peroxynitrite in this model.
Autosomal dominant periodic fevers are characterized by intermittent febrile attacks of unknown etiology and by recurrent abdominal pains. The biochemical and molecular bases of all autosomal dominant periodic fevers are unknown, and only familial Hibernian fever (FHF) has been described as a distinct clinical entity. FHF has been reported in three families-the original Irish-Scottish family and two Irish families with similar clinical features. We have undertaken a genomewide search in these families and report significant multipoint LOD scores between the disease and markers on chromosome 12p13. Cumulative multipoint linkage analyses indicate that an FHF gene is likely to be located in an 8-cM interval between D12S77 and D12S356, with a maximum LOD score (Z max) of 3.79. The two-point Z max was 3.11, for D12S77. There was no evidence of genetic heterogeneity in these three families; it is proposed that these markers should be tested in other families, of different background, that have autosomal dominant periodic fever, as a prelude to identification of the FHF-susceptibility gene.
Proximal interphalangeal (PIP) joint contractures are common complications in hand injuries and conditions such as Dupuytren's contracture. Conventional treatment such as splinting and serial casting may result in inadequate improvement. Operative release of the contracture may be complicated by neurovascular overstretch with injury to the digital nerves or vascular compromise. Gradual distraction of the contracted joint may prevent this neurovascular injury. The multiplanar distracter was designed for three-dimensional distraction of the mandible. Distraction may be obtained in the X, Y, or Z planes. With this device, the angular relationship between two planes may be altered. A 22-year-old male with a PIP joint contraction following replantation failed conventional treatment for release. With the use of a multiplanar distracter, the flexion contraction was reduced from 95 degrees to a more functional 30 degrees using gradual angular distraction. The angle between the proximal and middle phalanges were gradually changed using the ability of the distracter to change the angular relationship in the X-Y plane. At 3 and 6 months postdistraction, the patient has maintained his 30-degree flexion angle. The multiplanar distracter is a simple technique that may be useful for the treatment of PIP joint contractures that fail conventional therapy.
This study examined the effect of sodium citrate ingestion on high-intensity cycling performance in repeated 45-sec bouts. Twelve subjects (9 male and 3 female) ingested either a sodium citrate solution (0.3 g x kg-1 body mass[BM]) or a placebo 90 min prior to exercise. Postingestion blood HCO3 concentrations were significantly higher in the citrate trial (p<.01), but there was no difference over the five bouts (p<.05) and postexercise blood lactate concentrations significantly increased over the five bouts (p<0.01), but there were no differences between trials. We conclude that sodium citrate ingestion (0.3 g x kg-1 BM) is not an effective ergogenic aid for high-intensity, intermittent exercise as simulated in this protocol.