Exercise-induced alterations in skeletal muscle myosin heavy chain phenotype: dose-response relationship

This study investigated the effects of exercise training duration on the myosin heavy chain (MHC) isoform distribution in rat locomotor muscles. Female Sprague-Dawley rats (120 days old) were assigned to either a sedentary control group or to one of three endurance exercise training groups. Trained animals ran on a treadmill at approximately 75% maximal O2 uptake for 10 wk (4-5 days/wk) at one of three different exercise durations (30, 60, or 90 min/day). Training resulted in increases (P < 0.05) in citrate synthase activity in the soleus and extensor digitorum longus in both the 60 and 90 min/day duration groups and in the plantaris (Pla) in all three exercise groups. All durations of training resulted in a reduction (P < 0.05) in the percentage of MHCIIb and an increase (P < 0.05) in the percentage of MHCIIa in the Pla. The magnitude of change in the percentage of MHCIIb in the Pla increased as a function of the training duration. In the extensor digitorum longus, 90 min of daily exercise promoted a decrease (P < 0.05) in percentage of MHCIIb and increases (P < 0.05) in the percentages of MHCI, MHCIIa, and MHCIId/x. Finally, training durations >/=60 min resulted in an increase (P < 0.05) in the percentage of MHCI and a concomitant decrease (P < 0.05) in the percentage of MHCIIa in the soleus. These results demonstrate that increasing the training duration elevates the magnitude of the fast-to-slow shift in MHC phenotype in rat hindlimb muscles.

Differences between African American and Caucasian men participating in a community-based prostate cancer screening program

Prostate cancer is a major contributor to morbidity and mortality in the male population, but public awareness of the cancer has been reported as minimal. We evaluated the effectiveness of an educational prostate cancer screening program on 944 men in a midwest urban community. Digital rectal examinations and PSA blood tests were provided at no charge to participants with a grant from the Michigan Department of Community Health. An educational intervention that stressed the importance of prostate cancer early detection and treatment was conducted before screenings. A brief questionnaire administered before and after the videotape and screenings, targeted both knowledge and attitudes concerning prostate cancer. Pre-test results revealed that African American men were significantly (t = 3.7, P = .00) less likely then white men to correctly identify early symptoms of prostate cancer and the basic components of a prostate checkup. Following program involvement, scores significantly improved in all areas and differences were no longer significant between the races. Racial differences were also found for screening preferences and modes of reaching men to participate in screening. African American men were twice as likely as white men to choose private appointments over mass screening (OR = 2.2, P = .00). Radio reached the most African Americans (25%) while newspaper reached the most Caucasians (34%). The decreased level of knowledge among African Americans regarding prostate etiology and clinical factors highlights the need for educational programs to target minority populations. The need for discretion also applies by providing minority-favored access with screening through private appointments.

The role of the ran GTPase in nuclear assembly and DNA replication: characterisation of the effects of Ran mutants

The Ran GTPase plays a critical role in nucleocytoplasmic transport and has been implicated in the maintenance of nuclear structure and cell cycle control. Here, we have investigated its role in nuclear assembly and DNA replication using recombinant wild-type and mutant Ran proteins added to a cell-free system of Xenopus egg extracts. RanQ69L and RanT24N prevent lamina assembly, PCNA accumulation and DNA replication. These effects may be due to the disruption of nucleocytoplasmic transport, since both mutants inhibit nuclear import of a protein carrying a nuclear localisation signal (NLS). RanQ69L, which is deficient in GTPase activity, sequesters importins in stable complexes that are unable to support the docking of NLS-proteins at the nuclear pore complex (NPC). RanT24N, in contrast to wild-type Ran-GDP, interacts only weakly with importin alpha and nucleoporins, and not at all with the import factor p10, consistent with its poor activity in nuclear import. However, RanT24N does interact stably with importin beta, Ran binding protein 1 and RCC1, an exchange factor for Ran. We show that Ran-GDP is essential for proper nuclear assembly and DNA replication, the requirement being primarily before the initiation of DNA replication. Ran-GDP therefore mediates the active transport of necessary factors or otherwise controls the onset of S-phase in this system.

Meta-analysis of antisecretory and gastrokinetic compounds in functional dyspepsia

In view of therapeutic advances, we carried out meta-analysis of results from 18 randomized, controlled clinical studies to update a previous meta-analysis and to provide an overview of clinical trials involving treatment of functional dyspepsia. The studies were included only if they satisfied inclusion and exclusion criteria and assessed treatment of functional dyspepsia with the antisecretory compounds cimetidine and ranitidine and the gastrokinetic compounds cisapride and domperidone. Outcomes of each of these trials were classified in terms of differences in therapeutic success between active treatment and placebo. For antisecretory treatments, the 95% confidence intervals for the difference in therapeutic success between active treatment and placebo were inconsistent for cimetidine, but analysis of both ranitidine trials gave favorable results. For the gastrokinetic compounds cisapride and domperidone, the differences in success rates were generally higher and more in favor of active treatment than placebo. By combining the results from both antisecretory treatments and comparing them with the combined results for gastrokinetic compounds, we observed that gastrokinetic compounds had a greater difference in success rates than did antisecretory agents. Overall, our meta-analysis shows that antisecretory treatment with cimetidine or ranitidine offers little advantage over placebo, whereas gastrokinetic treatment with cisapride or domperidone is significantly better than placebo for treatment of functional dyspepsia.

The effect of dietary intervention on changes in total cholesterol, blood pressure and weight in a Cambridge study

The study examined the impact of dietary advice on cholesterol reduction, to see whether diet was more effective when preceded by a cholesterol estimation. A total of 635 healthy individuals aged between 40 and 60 years attended a general practice cardiovascular risk screening in 1990. All subjects had their blood pressure, body mass index and smoking history recorded, and 50% were randomised to cholesterol measurement. Two years later, all individuals were invited to participate in a follow-up screening and 356 individuals took part (158 men, 198 women). All the above estimations were undertaken in 100% of attendees. The mean total cholesterol levels and weight declined in the subjects who were given dietary advice and had their cholesterol measured, while the mean cholesterol level increased slightly in subjects who did not receive dietary advice but had their cholesterol measured. The was a significant increase in diastolic blood pressure in all patients. The figures for reported smokers decreased from 22.4% to 19.4% in men and 19.4% to 8.4% in women. The results suggest that dietary advice can achieve a sustained reduction in cholesterol levels, but may require the stimulus of a prior cholesterol estimation.

Extracellular degradation of agonists as an adaptive mechanism

Many cellular responses are initiated by the binding of an extracellular ligand to receptors at the cell surface. The removal of these ligands, or agonists, would therefore be expected to contribute to the process by which cells recover from stimulation. While dilution in the extracellular medium reduces the concentration of most agonists, many cells have developed specific mechanisms for removing particular ligands. One of the more effective mechanisms is to degrade the extracellular agonist and here we review the production and action of the enzymes responsible for the degradation of a number of these agonists.

HIV-1 reverse transcriptase codon 215 mutation in plasma RNA: immunologic and virologic responses to zidovudine. The AIDS Clinical Trials Group Study 175 Virology Team

Treatment of HIV infection with zidovudine (ZDV) may select for changes in the genetic sequence of the viral reverse transcriptase (RT) that imparts drug resistance. The presence of a 2-bp mutation at codon 215 of RT (from threonine to phenylalanine or tyrosine) was assessed in plasma viral RNA in 85 subjects treated with ZDV in the AIDS Clinical Trials Group (ACTG) 175 virology substudy. Median CD4 cell numbers, HIV plasma RNA levels, and infectious titers of virus were significantly different over 56 weeks of treatment among 58 subjects with the wild-type threonine at codon 215 virus at study entry compared with the 27 subjects with mutations to phenylalanine or tyrosine (MUT) virus. Thirty percent (13 of 44 subjects) with wild-type virus at study entry developed a new codon 215 mutation. Genotypic resistance at codon 215 in plasma HIV RNA is associated with the subsequent immunologic and virologic failure of ZDV monotherapy in subjects with 200 to 500 CD4 cells/mm3.

Survey of the Free and Conjugated Myricetin and Quercetin Content of Red Wines of Different Geographical Origins

Gradient reversed-phase HPLC was used to obtain quantitative estimates of the levels of free and conjugated myricetin and quercetin in 65 red wines from Italy, Chile, France, California, Australia, Bulgaria, Spain, Romania, New Zealand, Brazil, Morocco, and Hungary. The concentrations of total flavonols ranged from 4.6 to 41.6 mg L(-1). High total flavonol levels appear to be associated with the use of thick-skinned grape varieties, such as Cabernet Sauvignon, with a high skin:volume ratio, which were left to ripen fully in sunny conditions before harvest and which were extracted efficiently by modern methods of vinification. Some Chilean Cabernet Sauvignon wines contained up to 40 mg of total flavonols L(-1), which was higher than the levels detected in Cabernet Sauvignon from France, California, and Australia. The flavonol content of 1989 and 1990 Cabernet Sauvignon from Bulgaria was <6 mg L(-1). Chilean Cabernet Sauvignon, Merlot, and Pinot Noir all contained consistently higher concentrations of flavonols than their counterparts from different geographical regions.

The processing of yeast pheromones

Yeast provides an attractive system in which to study proprotein processing. Many of their processing events are remarkably similar to those in higher eukaryotes and their amenability to experimental manipulation permits approaches that are not always feasible in multicellular organisms. Analysing the biosynthesis of the yeast mating pheromones has been particularly rewarding and has provided insights into both the proteolytic aspects of processing and other post-translational events such as prenylation and carboxymethylation.

Managing care in an integrated delivery system via an Intranet

The CareGroup Provider Service Network is a managed care contracting organization which provides central administrative services for over 1800 physicians and 200,000 managed care lives. Services include utilization management, disease management and credentialing for the entire network. The management model of the Provider Service Network empowers local physician groups with information and education. To meet the managed care information needs of the network, we implemented an intranet-based executive information system, PSNWeb, which retrieves data from a managed care data warehouse. The project required the integration of diverse technologies and development of a complex security/confidentiality infrastructure to deliver information to 8 major clinician groups, each with different information needs.

Xenopus Ran-binding protein 1: molecular interactions and effects on nuclear assembly in Xenopus egg extracts

Ran is a nuclear GTPase implicated in nucleocytoplasmic transport, the maintenance of nuclear structure, mRNA processing, and cell cycle regulation. By two-hybrid interaction in yeast, we have identified a Xenopus homologue of Ran-binding protein 1 (RanBP1). Xenopus RanBP1 interacts specifically with the GTP-bound form of Ran and forms complexes in Xenopus egg extracts with Ran, importin-beta/karyopherin-beta and importin-alpha/karyopherin-alpha, but not p10, p120/RanBP7, RanBP2 or other nucleoporins. These complexes may play roles in the recycling of Ran and importins/karyopherins during nucleocytoplasmic transport. Increased concentrations of RanBP1 stabilise an interaction between Ran and RCC1 in egg extracts, inhibiting the exchange activity of RCC1 towards Ran. Under these conditions, the assembly of nuclei from chromatin is dramatically affected: the nuclei do not assemble a lamina and become very small with homogeneously condensed chromatin. They fail to actively import proteins and do not undergo DNA replication. By field emission in-lens scanning electron microscopy, we show that these nuclei have an intact nuclear envelope containing pore complexes, but the envelope is highly convoluted. However, RanBP1 does not directly inhibit nuclear protein import in assembled nuclei. These results suggest that RCC1 and/or Ran have a function early in nuclear assembly that is disrupted by RanBP1.

Does allopurinol reduce pain of chronic pancreatitis?

CONCLUSION

A dosage of 300 mg/d of allopurinol was not effective in reducing pain or improving activities of daily living in chronic pancreatitis.

BACKGROUND

Allopurinol prevents the generation of oxygen-derived free radicals by inhibiting xanthine oxidase. The purpose of this study was to determine whether allopurinol is effective in reducing pain of chronic pancreatitis.

METHODS

Thirteen patients with chronic pancreatitis who were experiencing abdominal pain requiring medication at least three times each week entered a randomized, double-blind, two-period crossover clinical trial. Patients evaluated their pain daily using a categorical pain intensity scale, numeric pain intensity scale, and a visual analog scale, and weekly completed a McGill Pain Questionnaire and activities of daily living (ADL) questionnaire.

RESULTS

The mean baseline score of pain was approx 50% of most severe pain in all scoring systems. There was no significant decrease in pain associated with allopurinol compared to the placebo (p = 0.24-0.75). In addition, there was no benefit in terms of ADL score associated with allopurinol compared with placebo (p = 0.32). Mean uric acid level was decreased by 1.15 mg/dL while patients were taking allopurinol, compared to when they were taking placebo (p = 0.007).

The cysteine residues of the M2 protein are not required for influenza A virus replication

The M2 protein of influenza A virus functions as an ion channel. It contains three cysteine residues: cysteines 17 and 19, which form disulfide bonds in the ectodomain, and cysteine 50 which is acylated. To understand the role of these cysteine residues in virus replication, we used reverse genetics to create influenza viruses in which the individual cysteines were mutated and a virus in which all three cysteines were changed to serine. The M2 cysteine mutants that lacked either of the cysteine residues in the ectodomain and the mutant that lacked all three residues had appreciably lower amounts of M2 oligomers than did the wild-type virus when examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. None of the mutants, however, were defective in replication, either in vitro or in ferrets and mice. These findings demonstrate that noncovalent interactions are sufficient for the M2 protein to form functional oligomers for virus replication and that its cysteine residues are dispensable for influenza virus replication in vitro and in vivo.

Does pancreatic enzyme supplementation reduce pain in patients with chronic pancreatitis: a meta-analysis

OBJECTIVE

Pancreatic enzyme therapy is widely used in the treatment of pain in chronic pancreatitis. The aim of our study was to perform a meta-analysis to determine whether pancreatic enzyme supplementation significantly decreases abdominal pain in patients with chronic pancreatitis.

METHODS

From a MEDLINE search, we identified, evaluated, and subjected to a meta-analysis, six randomized, double-blind, placebo-controlled trials. Important features of data extraction included the method of subject inclusion, definition of disease, enzyme preparation, response to pancreatic enzyme therapy versus placebo, and modality for measuring response.

RESULTS

In the meta-analysis, the pooled estimate of the percentage of patients per study who preferred enzymes relative to placebo was 52% (95% confidence interval, 45-60%). A test of homogeneity indicated that there was no statistically significant heterogeneity across studies in the percentage of patients preferring enzymes.

CONCLUSION

Statistical analysis demonstrates no significant benefit of supplemental pancreatic enzyme therapy to relieve pain associated with chronic pancreatitis.

Pleural effusion as a predictor of severity in acute pancreatitis

Our objective was to determine whether pleural effusion is a predictor of severity in acute pancreatitis and, if so, whether it is an independent predictor. One hundred ninety-six consecutive cases of acute pancreatitis from October 1, 1994, to September 30, 1995, were reviewed. Medical records were analyzed for evidence of pleural effusion by chest radiograph and severe acute pancreatitis by identification of pancreatic necrosis or organ system dysfunction. Data were analyzed to determine if identification of pleural effusion provided an early sign of severity. Among 135 patients who underwent chest radiography, pleural effusion was seen in 16 of 19 (84.2%) with severe pancreatitis and 10 of 116 (8.6%) of patients with mild pancreatitis (p < 0.001). Pleural effusion was noted in severe pancreatitis prior to clinical or computed tomography evidence of severity in only 20% of cases. Pleural effusion is strongly associated with severity in acute pancreatitis but provides independent information on severity in only a minority of cases.

Relationship of necrosis to organ failure in severe acute pancreatitis

BACKGROUND & AIMS

Pancreatic necrosis and organ failure are principal determinants of severity in acute pancreatitis. The purpose of this study was to determine the relationship of necrosis to organ failure in severe acute pancreatitis.

METHODS

Patients with necrotizing pancreatitis from May 1992 to January 1996 were retrospectively studied. Pancreatic necrosis was identified by characteristic findings on dynamic contrast-enhanced computerized tomography scan and infected necrosis by computerized tomography-guided percutaneous aspiration. Organ dysfunction was defined in accordance with the Atlanta symposium.

RESULTS

Organ failure was present in only 26 of 51 patients (51%). There was no difference in the prevalence of organ failure in infected necrosis compared with sterile necrosis (approximately 50% in both groups). Patients with increased amounts of necrosis did not have an increased prevalence of organ failure or infected necrosis compared with those with lesser amounts of necrosis. Patients with organ failure had an increased morbidity and mortality compared with those without organ failure.

CONCLUSIONS

Organ failure occurred in only one half of patients with necrotizing pancreatitis. Because organ failure increases the severity of illness, studies of patients with necrotizing pancreatitis must stratify for organ failure to facilitate interpretation of results.

The optimum bowel preparation for flexible sigmoidoscopy

With the proposed introduction of a flexible sigmoidoscopic screening programme for colorectal cancer, patient compliance is of paramount importance. Therefore, the bowel preparation providing optimum cleansing of the bowel with the least associated discomfort and inconvenience for the patient must be found. Patients were randomized to receive either Picolax the evening before the examination or self-administered Fleet enemas prior to the investigation. The endoscopist and nurse practitioner who collected data on a standard questionnaire were blinded to the preparation used. Bowel preparation was graded by the endoscopist as: excellent, good, adequate or poor. One hundred and two consecutive patients were randomized: 56 to the Fleet enema group and 46 to the Picolax group. Self-administered Fleet enemas provided a significantly superior bowel preparation with 52 (93%) being judged adequate or better, as opposed to 34 (74%) in the Picolax group. In addition, Fleet enemas were associated with significantly fewer adverse associated symptoms: 11 (20%) vs 24 (52%). Patients reported to be willing to receive Fleet enemas again in 53 (95%) vs 37 (80%) for the Picolax group. The self-administered Fleet enema is superior to Picolax in terms of bowel preparation for flexible sigmoidoscopy and the incidence of associated adverse symptoms.