Genotypic and phenotypic analysis of Borrelia burgdorferi isolates from The Netherlands.

Sixty-three Borrelia burgdorferi isolates recovered from Ixodes ricinus ticks collected in 17 locations in The Netherlands and three Dutch human skin isolates were characterized by rRNA gene restriction fragment length polymorphism, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blotting (immunoblotting). All three human isolates belonged to B. burgdorferi group VS461. Of the tick isolates, 29 (46%) were B. burgdorferi sensu stricto, 2 (3%) were group VS461, 19 (30%) were Borrelia garinii, and 13 (21%) were different from any previously described genomic species. On the basis of the criteria described, 12 isolates formed a distinct genomic group, designated M19. rRNA gene restriction patterns of the group M19 isolates resembled but were not identical to the B. garinii patterns. Hybridization of digested DNA with a flagellin probe confirmed the separation of group M19 from the B. garinii isolates. One isolate, M63, was different from all the others. In conclusion, the occurrence of B. burgdorferi sensu stricto, B. garinii, and B. burgdorferi group VS461 in ticks from The Netherlands corresponds with the occurrence of these genomic species among tick isolates from other European countries. However, our findings suggest that B. burgdorferi sensu lato probably contains more than three genomic species.     

Persistent rat cytomegalovirus (RCMV) infection of the salivary glands contributes to the anti-RCMV humoral immune response

The salivary glands are the major sites of persistent replication of rat cytomegalovirus (RCMV). At several months post infection (pi), infectious RCMV is usually still produced in the salivary glands but not in any other organ or tissue of the rat. To investigate whether the persistence of RCMV in the salivary glands is crucial to the pathogenesis of viral infection, we monitored the progression of RCMV-induced disease in rats from which the salivary glands had been surgically removed (desalivated) as well as in sham-operated rats, both after a lethal and sublethal challenge with RCMV. Desalivation did not have a significant effect on either RCMV-induced morbidity or mortality. As expected, at 1 year pi, relatively high levels of infectious virus were detected in the salivary glands of sham-operated rats, whereas neither infectious virus nor RCMV DNA could be detected in liver, spleen and lungs of these animals. Infectious virus and viral DNA were also undetectable in organs from desalivated animals at 1 year pi. Surprisingly, a difference was found between desalivated and sham-operated rats in the titers of anti-RCMV IgG antibodies, which were significantly higher in sham-operated rats than in desalivated animals at 183, 295 and 365 days pi. This finding indicates that the persistence of RCMV in the salivary glands may contribute significantly to the anti-RCMV humoral immunity of infected rats.     

Computer-controlled mechanical lung model for application in pulmonary function studies

A computer controlled mechanical lung model has been developed for testing lung function equipment, validation of computer programs and simulation of impaired pulmonary mechanics. The construction, function and some applications are described. The physical model is constructed from two bellows and a pipe system representing the alveolar lung compartments of both lungs and airways, respectively. The bellows are surrounded by water simulating pleural and interstitial space. Volume changes of the bellows are accomplished via the fluid by a piston. The piston is driven by a servo-controlled electrical motor whose input is generated by a microcomputer. A wide range of breathing patterns can be simulated. The pipe system representing the trachea connects both bellows to the ambient air and is provided with exchangeable parts with known resistance. A compressible element (CE) can be inserted into the pipe system. The fluid-filled space around the CE is connected with the water compartment around the bellows; The CE is made from a stretched Penrose drain. The outlet of the pipe system can be interrupted at the command of an external microcomputer system. An automatic sequence of measurements can be programmed and is executed without the interaction of a technician.     

Daytime sleep in myotonic dystrophy is not caused by sleep apnoea.

Daytime sleepiness is common in myotonic dystrophy and might be attributed to disturbed nocturnal breathing. Seventeen out of 22 patients complained of excessive daytime sleepiness, resembling "idiopathic hypersomnolence". Sleep apnoea might have contributed to daytime sleepiness in only three of 17 patients. Treatment with the central stimulant methylphenidate produced sustained benefit in seven out of 11 patients tested. Daytime sleepiness in myotonic dystrophy is usually caused by dysfunction of central sleep regulation and not by disturbed nocturnal breathing.     

Effects of cimetidine and ranitidine on interdigestive and postprandial lower esophageal sphincter pressures and plasma gastrin levels in normal subjects

The purpose of this study was to investigate the effects of cimetidine and ranitidine on human lower esophageal sphincter pressure (LESP) and plasma levels of gastrin in all phases of the interdigestive motor complex and after a test meal. In a random, double-blind manner, placebo, cimetidine (1.0 mg/kg X h), and ranitidine (0.16 mg/kg X h) were administered by intravenous infusion to nine healthy volunteers. By using a sleeve catheter assembly, LESP was constantly monitored, as were esophageal, fundic, antral, and duodenal pressures. Considerable minute-to-minute and interdigestive motor phase-related LESP variations were observed. Cimetidine and ranitidine decreased the interdigestive LESP, but did not abolish the gradual increase in LESP from phase I to phase III. During the first 2 h after the meal, cimetidine and ranitidine had no significant effect on LESP. Plasma gastrin levels were increased by cimetidine and ranitidine, both in the interdigestive and in the postprandial state. The results indicate that the effect of H2-blockers on LESP is not gastrin-mediated. The results further indicate that, in studies on the effects of drugs on LESP, prolonged recording of LESP in all motor states is a prerequisite.     

Radiography in acute ankle injuries: the Ottawa Ankle Rules versus local diagnostic decision rules

STUDY OBJECTIVE: We validate the Ottawa Ankle Rules and 2 Dutch ankle rules in distinguishing clinically significant fractures from insignificant fractures and other injuries in patients with a painful ankle presenting to the emergency department. METHODS: This prospective comparison of 3 ankle rules was conducted in the ED of a 580-bed community teaching hospital in Amsterdam from January 1998 to April 1999. Participants included 647 consecutive patients aged 18 years or older presenting with a painful ankle after trauma. All physicians received extensive and pictorial training on how to correctly score the respective items of the rules. The physician on call recorded these items derived from history and physical examination on a standardized data sheet. All patients subsequently underwent standard radiographic assessment. A radiologist and a trauma surgeon evaluated the radiographs blinded from the results of the data sheet form and the treatment given. The diagnostic performance of the 3 rules was measured in terms of sensitivity, specificity, and the reduction of radiographs. Receiver operating characteristic (ROC) curves were constructed, and the area under the ROC curves was calculated and compared. RESULTS: Seventy-four fractures were seen, of which 41 were clinically significant. The Ottawa Ankle Rules had a sensitivity of 98% for identifying clinically significant fractures; the local rules scored 88% and 59%, respectively. The potential savings in radiographs for the 3 decision rules were 24%, 54%, and 82%, respectively. The area under the ROC curve was better for both the local rules (0.84 and 0.83) compared with the Ottawa Ankle Rules (0.76). CONCLUSION: Because the identification of all relevant fractures is more important than a reduction in radiographs, the higher sensitivity of the Ottawa Ankle Rules makes these most suitable for implementation in The Netherlands.     

Exercise tolerance,lung function abnormalities,anemia, and cardiothoracic ratio in sickle cell patients

Many patients with sickle cell disease (SCD) have a reduced exercise capacity and abnormal lung function. Cardiopulmonary exercise testing (CPET) can identify causes of exercise limitation. Forty‐four consecutive SCD patients (27 HbSS, 11 HbSC, and 6 HbS‐beta thalassemia) with a median age (interquartile range) of 26 (21–41) years underwent pulmonary function tests, CPET, chest x‐ray, and echocardiography to further characterize exercise limitation in SCD. Peak oxygen uptake (V′O₂‐peak), expressing maximum exercise capacity, was decreased in 83% of the studied patients. V′O₂‐peak correlated with hemoglobin levels (R = 0.440, P = 0.005), forced vital capacity (FVC) (R = 0.717, P < 0.0001). Cardiothoracic ratio on chest x‐ray inversely correlated with FVC (R = ?0.637, P < 0.001). According to criteria for exercise limitation, the patients were limited in exercise capacity due to anemia (n = 17), cardiovascular dysfunction (n = 2), musculoskeletal function (n = 10), pulmonary ventilatory abnormalities (n = 1), pulmonary vascular exercise limitation (n = 1), and poor effort (n = 3). In the present study we demonstrate that anemia is the most important determinant of reduced exercise tolerance observed in SCD patients without signs of pulmonary hypertension. We found a strong correlation between various parameters of lung volume and cardiothoracic ratio and we hypothesize that cardiomegaly and relative small chest size may be important causes of the impairment in pulmonary function, that is, reduced long volumes and diffusion capacity, in SCD. Taking into account anthropomorphic differences between SCD patients and controls could help to interpret lung function studies in SCD better. Am. J. Hematol. 89:819–824, 2014. © 2014 Wiley Periodicals, Inc.