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Biomedical subjects

E Barnes

Publications and source records attributed to E Barnes.

At least 37 records · Page 2Linked to original sources

Long-term efficacy of treatment of chronic hepatitis C with alpha interferon or alpha interferon and ribavirin.

The major objective of treatment of chronic hepatitis C virus (HCV) infection is to prevent progression to cirrhosis, and thereby prevent complications of end-stage liver disease. The established treatment of chronic HCV is with alpha interferon. Recent results with ribavirin and alpha interferon together suggest that combination antiviral therapy will become the benchmark treatment. For both naive and relapsed patients, however, it has become important to assess the long-term outcome of treatment, in order to gauge whether treatment has indeed modified the natural history of chronic hepatitis C virus infection. It seems likely that most sustained responders (85-90%) treated with combination ribavirin and alpha interferon will continue to have a long-term biochemical and virological response, as has been demonstrated with alpha interferon alone, but further long-term follow-up of patients treated with combination therapy is required.

Antiviral Agents↗

Predictors of a favorable response to alpha interferon therapy for hepatitis C.

The most consistently identified predictive factors for a response to both IFN-alpha monotherapy and IFN-alpha in combination with ribavirin are a low HCV RNA level, the absence of fibrosis, infection with HCV genotype 2 and 3, and a prolonged duration of treatment. In addition, an early response to IFN-alpha predicts response to IFN-alpha monotherapy but not necessarily to combination therapy. There does not appear to be any major gain in treating IFN-naive patients with HCV genotype 2 or 3 infection with a combination of IFN-alpha and ribavirin for longer than 6 months. The identification of these predictive factors has allowed improvement in study design and assessment and may provide a patient with an idea of the likelihood of response, making possible a more informed decision regarding treatment. At present, none of these factors, either alone or in combination, completely predicts response to IFN-alpha. Thus, individual patients should not be denied treatment on the basis of these factors.

Alanine Transaminase↗

Long-term survival of VDD pacing.

UNLABELLED: All patients with VDD systems implanted at a tertiary pacing center were identified from a computer database and data collected on pacing indications, follow-up duration, rate response, reasons for programming changes, and implant P wave amplitudes. RESULTS: 366 implants were identified for which complete data were available for 335 leads implanted in 316 patients. The mean follow-up period was 24.1 months, and age at implant was 73.5 +/- 11.8 years. During follow-up, 19 patients died (6%) and 62 (19.6%) were followed elsewhere. Indications for pacing were complete heart block, 56.6%; intermittent AV block, 21.8%; postablation complete heart block, 5.4%; 2:1 AV block, 13%; and others, 3.2%. Two groups: no mode change (NMC, n = 280) and mode change (MC, n = 36) were identified. Reasons for reprogramming in the MC group were as follows: atrial sensing, 11; AF/atrial flutter, 18; chronotropic incompetence, 3; and others 4. Significantly more MC patients had rate response programmed ON (44.4% vs 22.1%, P < 0.05). No significant differences between the two groups were found in other variables, including male gender (55.5% vs 54.6%), length of follow-up (27.1 +/- 17.8 vs 23.8 +/- 20.6 months), age at last follow-up (72 +/- 12.3 vs 75.9 +/- 11.9 years), and P wave amplitude (1.7 +/- 0.9 vs 1.8 +/- 0.9 mV). CONCLUSION: Reprogramming of VDD systems is infrequent. When necessary, it is usually prompted by atrial arrhythmias or failure of atrial sensing. When adequate atrial chronotropy has been verified, VDD is an acceptable alternative to DDD pacing and survives well over the long term.

Aged↗

Compared with parenteral nutrition, enteral feeding attenuates the acute phase response and improves disease severity in acute pancreatitis.

BACKGROUND: In patients with major trauma and burns, total enteral nutrition (TEN) significantly decreases the acute phase response and incidence of septic complications when compared with total parenteral nutrition (TPN). Poor outcome in acute pancreatitis is associated with a high incidence of systemic inflammatory response syndrome (SIRS) and sepsis. AIMS: To determine whether TEN can attenuate the acute phase response and improve clinical disease severity in patients with acute pancreatitis. METHODS: Glasgow score, Apache II, computed tomography (CT) scan score, C reactive protein (CRP), serum IgM antiendotoxin antibodies (EndoCAb), and total antioxidant capacity (TAC) were determined on admission in 34 patients with acute pancreatitis. Patients were stratified according to disease severity and randomised to receive either TPN or TEN for seven days and then re-evaluated. RESULTS: SIRS, sepsis, organ failure, and ITU stay, were globally improved in the enterally fed patients. The acute phase response and disease severity scores were significantly improved following enteral nutrition (CRP: 156 (117-222) to 84 (50-141), p < 0.005; APACHE II scores 8 (6-10) to 6 (4-8), p < 0.0001) without change in the CT scan scores. In parenterally fed patients these parameters did not change but there was an increase in EndoCAb antibody levels and a fall in TAC. Enterally fed patients showed no change in the level of EndoCAb antibodies and an increase in TAC. CONCLUSION: TEN moderates the acute phase response, and improves disease severity and clinical outcome despite unchanged pancreatic injury on CT scan. Reduced systemic exposure to endotoxin and reduced oxidant stress also occurred in the TEN group. Enteral feeding modulates the inflammatory and sepsis response in acute pancreatitis and is clinically beneficial.

APACHE↗

Is intervention necessary after a first episode of acute idiopathic pancreatitis?

Acute idiopathic pancreatitis is a term used when no underlying cause has been identified on routine investigation. However, more specialised investigations may identify aetiological factors, biliary sludge and sphincter of Oddi dysfunction for example, in 38-72% of patients with recurrent episodes. Treatment of these abnormalities may prevent further episodes of pancreatitis. The aim of this study was to follow up and determine the outcome in patients with a first episode of idiopathic pancreatitis, and thus determine the need for further investigation and treatment in this group of patients. Thirty one patients with a single episode of idiopathic pancreatitis were studied who had no specialised investigations or specific treatment. During a median follow up of 36 months only one patient has had recurrent pancreatitis. Two patients experienced a single episode of unexplained abdominal pain; serum amylase, liver biochemistry, and abdominal ultrasound were all normal and the pain resolved within 48 hours. In conclusion, in the medium term, the prognosis is good after a first episode of idiopathic pancreatitis and specialised investigation is unnecessary.

Acute Disease↗

Glomerulonephritis associated with permanent pacemaker endocarditis.

Two patients with permanent transvenous cardiac pacemakers were seen with a history of pyrexia of unknown origin and renal failure. After extensive investigation both were found to have pacemaker endocarditis. A renal biopsy of one patient revealed changes characteristic of glomerulonephritis associated with this condition. Both patients underwent thoracotomy for open removal of their pacemaker and appropriate antibiotic treatment. One patient made a good recovery of renal function. Unfortunately the second patient died. These reports emphasize the need for vigilance for these two uncommon complications and the difficulty in their diagnosis.

Aged↗

Phenytoin and plasmapheresis: importance of sampling times and impact of obesity.

The effect of plasmapheresis (PP) on total and free phenytoin clearance is reported. An obese patient with the diagnosis of thrombotic thrombocytopenic purpura (TTP) was treated with PP. Twelve episodes of PP, having exchange volumes of 1.5-2.25 times the plasma volume with a mean +/- SD 7.7 +/- 0.8 L of plasma removed, were studied. A significant (p < 0.05) difference was observed with a mean change in plasma phenytoin concentrations from pre- to end-PP of 7.32 +/- 2.5 mg/L compared to 1.98 +/- 0.7 mg/L observed pre-PP to 1 h post-PP. These values corresponded to 48.4 +/- 11.6 and 15.0 +/- 6.7% decreases in phenytoin concentrations at the two aforementioned time periods. To prevent misinterpretation of plasma phenytoin concentrations, samples should not be obtained for at least 2 h after PP.

Blood Specimen Collection↗

Dietary chloride and urinary calcium in stone disease.

We studied six patients with renal stone disease, hypercalciuria, cystinuria and/or hyperuricosuria, during variations in dietary Na and Cl intake. Switching between equimolar NaCl and NaHCO3 intakes reduced urinary Ca (UCa) during the NaHCO3 phase, despite steady-state urinary Na. Switching between equimolar NaCl and KCl did not change UCa, despite a sharp fall in UNa. The results suggest a predominant role for Cl rather than Na ions during sodium-chloride-induced changes in UCa. In stone disease of mixed aetiology, where alkalinization of the urine as well as reduction in UCa may be desirable, treatment with NaHCO3 loading is not accompanied by a rise in UCa, provided that dietary Cl is maintained moderately low at 80-100 mmol/day. The mechanism whereby Cl intake influences UCa remains undefined. Plasma PTH and calcitriol levels showed no significant alteration, and atrial natriuretic peptide levels in one patient remained unchanged.

Calcium↗

L-lyxose metabolism employs the L-rhamnose pathway in mutant cells of Escherichia coli adapted to grow on L-lyxose.

Escherichia coli cannot grow on L-lyxose, a pentose analog of the 6-deoxyhexose L-rhamnose, which supports the growth of this and other enteric bacteria. L-Rhamnose is metabolized in E. coli by a system that consists of a rhamnose permease, rhamnose isomerase, rhamnulose kinase, and rhamnulose-1-phosphate aldolase, which yields the degradation products dihydroxyacetone phosphate and L-lactaldehyde. This aldehyde is oxidized to L-lactate by lactaldehyde dehydrogenase. All enzymes of the rhamnose system were found to be inducible not only by L-rhamnose but also by L-lyxose. L-Lyxose competed with L-rhamnose for the rhamnose transport system, and purified rhamnose isomerase catalyzed the conversion of L-lyxose into L-xylulose. However, rhamnulose kinase did not phosphorylate L-xylulose sufficiently to support the growth of wild-type E. coli on L-lyxose. Mutants able to grow on L-lyxose were analyzed and found to have a mutated rhamnulose kinase which phosphorylated L-xylulose as efficiently as the wild-type enzyme phosphorylated L-rhamnulose. Thus, the mutated kinase, mapped in the rha locus, enabled the growth of the mutant cells on L-lyxose. The glycolaldehyde generated in the cleavage of L-xylulose 1-phosphate by the rhamnulose-1-phosphate aldolase was oxidized by lactaldehyde dehydrogenase to glycolate, a compound normally utilized by E. coli.

Acetaldehyde↗