Assessment of three methods of pH probe positioning in preterm infants

BACKGROUND: In the assessment of gastroesophageal reflux, correct placement of the pH catheter is crucial. This is particularly so in very low birth weight infants where a small error in positioning could give rise to a potentially large error in results. Accepted modes of assessing correct positioning can be problematic in this population of infants and alternative methods were investigated. METHODS: A total of 26 preterm infants (<35 weeks gestation) were enrolled in this study. All infants were suspected of having GOR and pH monitoring was performed. Probe position was assessed using Strobel's formula, manometry and acid-alkali interface and confirmed by chest x-ray. RESULTS: There was a highly significant positive correlation between the calculation of the pH probe position using Strobel's formula and the position on x-ray and a significant positive correlation between the acid/alkali interface and x-ray position. There was no correlation between manometry and x-ray position and this method was also shown to be problematic in its' application. CONCLUSION: The data suggests that it is appropriate to use Strobel's formula as a method of accurate positioning of pH probes in preterm infants, thus avoiding the need for additional x-rays. The acid/alkali interface, when obtainable, is a secondary, satisfactory method to confirm the position calculated by Strobel's formula.     

Seizure induced dentate neurogenesis does not diminish with age in rats

Neurogenesis in the mammalian dentate gyrus occurs throughout life, is believed to be important for the laying down of episodic memory and diminishes significantly with increasing age. Pathological insults such as seizures, hypoxia and traumatic brain injury increase dentate neurogenesis compared to age matched controls. Using unilateral intracerebroventricular kainate we show that although baseline neurogenesis is significantly lower in 3 month old rats compared to 1 month old rats, kainate increases neurogenesis to reach similar levels in both age groups. Additionally, this effect is bilateral after a unilateral intracerebroventricular kainate injection. We conclude that the potential for dentate neurogenesis is maintained despite diminishing baseline levels with increasing age and that injury signals override the age related suppression of neurogenesis.     

Successful treatment of murine beta-thalassemia intermedia by transfer of the human beta-globin gene

The beta-thalassemias are caused by more than 200 mutations that reduce or abolish beta-globin production. The severity of the resulting anemia can lead to lifelong transfusion dependency. A genetic treatment based on globin gene transfer would require that transgene expression be erythroid specific, elevated, and sustained over time. We report here that long-term synthesis of chimeric hemoglobin (mualpha(2):hubeta(A)(2)) could be achieved in mice with beta-thalassemia intermedia following engraftment with bone marrow cells transduced with a lentiviral vector encoding the human beta-globin gene. In the absence of any posttransduction selection, the treated chimeras exhibit durably increased hemoglobin levels without diminution over 40 weeks. Ineffective erythropoiesis and extramedullary hematopoiesis (EMH) regress, as reflected by normalization of spleen size, architecture, hematopoietic colony formation, and disappearance of liver EMH. These findings establish that a sustained increase of 3 to 4 g/dL hemoglobin is sufficient to correct ineffective erythropoiesis. Hepatic iron accumulation is markedly decreased in 1-year-old chimeras, indicating persistent protection from secondary organ damage. These results demonstrate for the first time that viral-mediated globin gene transfer in hematopoietic stem cells effectively treats a severe hemoglobin disorder.     

Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing time

This study compared the surface texture of resin-modified glass ionomer cements after immediate and delayed finishing with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of 64 freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (3M-ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-fluted tungsten carbide burs. The teeth were then randomly divided into four groups of 16 teeth. Half of the teeth in each group were finished immediately, while the remaining half were finished after one-week storage in distilled water at 37 degrees C. The following finishing/polishing systems were employed: (a) Robot Carbides; (b) Super-Snap system; (c) OneGloss and (d) CompoSite Polishers. The mean surface roughness (microm; n=8) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Ra values were generally lower in both vertical and horizontal axis with delayed finishing/polishing. Although significant differences in RaV and RaH values were observed among several systems with immediate finishing/polishing, only one (Fuji II LC: RaH - Super-Snap < Robot Carbides) was observed with delayed finishing.     

Effect of chronic treatment with bovine recombinant growth hormone on cardiac dysfunction and lesion progression in UM-X7.1 cardiomyopathic hamsters

In view of the potentially beneficial effect of GH on ventricular function of humans suffering from idiopathic dilated cardiomyopathy, we undertook a study to evaluate the optimal time to initiate treatment with GH and its duration in UM-X7.1 cardiomyopathic hamsters (CMH). GH (1 mg/kg.d) therapy was initiated either in the early or late (30 and 160 d old, respectively) phases of the disease and continued until death at 240 d of age. Age- and sex-matched Golden Syrian hamsters (GSH) were used as controls. Basal IGF-1 levels in serum were reduced by nearly half in CMH compared with GSH but were increased within a physiological range in male hamsters. In contrast, female hamsters presented elevated basal serum IGF-1 levels that were not further elevated by GH administration, as reported in experimental models and humans. Accordingly, the present study will focus on the effects of GH therapy on cardiac performance in male hamsters. GH did not improve ventricular function when starting at a late stage of the disease compared with CMH controls. Maximum rate of left ventricular pressure development decreased by approximately 64% in CMH treated early with recombinant bovine GH. Ventricular dysfunction was associated with morphologic indices of hypertrophy, ventricular dilatation, and extensive fibrosis. Mortality was strikingly increased in GH-treated CMH for 210 d (four males and eight females), as opposed to four females (and no male) in the vehicle-treated group. These results suggest that chronic treatment with recombinant bovine GH in CMH, starting at an early stage of lesion development, is associated with a reduced cardiac performance at the terminal stage of the disease.     

Significance of random bladder biopsies in superficial bladder cancer

OBJECTIVES: We investigated to what extent biopsies of normal-appearing urothelium taken from patients with superficial bladder cancer (Ta, T1, Tis) showed malignant disease and whether those findings had impact on therapeutical decisions. PATIENTS AND METHODS: 1033 consecutive patients presenting with Ta, T1 or Tis (carcinoma in situ) superficial bladder tumors at increased risk for recurrence underwent multiple random biopsies from normal-appearing urothelium during transurethral resection (TUR). Patients with small, primary, singular tumors (smaller or equal to 1cm) were excluded from random biopsies. RESULTS: No tumor was found in the random biopsies of 905 patients (87.6%). 128 patients (12.4%) showed urothelial bladder cancer in their random biopsies (Tis: 74, Ta: 41, T1: 12, T2: 1). In 14 patients, where transurethral resection of the primary tumor revealed no signs of malignancy, urothelial bladder cancer was detected in the random biopsy material: Ta 8 patients, Tis 5 patients and T1 one patient. 21 patients with Ta tumors and 29 patients with T1 disease showed concomitant Tis. Upstaging of the primary, resected tumor by histological examination of the random biopsy material occurred in 75 patients (7%). Altogether, due to the random biopsy results therapy was altered in 70 patients (6.8%) of our series: It changed intravesical chemotherapy to BCG in 45, provoked a second TUR in 48 and cystectomy in 15 patients. CONCLUSIONS: While the clinical significance of random biopsies is still controversial, random biopsy results had strong impact on therapeutical decisions in our series. Regarding random bladder biopsies a simple tool for the urologist to identify high risk groups of patients, we recommend them as part of the routine management of superficial bladder cancer.     

Monocular chromatic contrast threshold and achromatic contrast sensitivity in children born prematurely

PURPOSE: To study the effect of prematurity on monocular chromatic contrast thresholds (CCT) and achromatic contrast sensitivity (ACS). DESIGN: Case-control study. METHODS: A prospective study of 59 children born at less than 33 weeks' gestation was undertaken. Subjects were identified during routine neonatal screening for retinopathy of prematurity and recalled for testing at age 7 to 13 years. Five had stage 1 retinopathy of prematurity, seven had stage 2, and three had stage 3. Sixty-eight full-term children were recruited as controls. Those with major cerebral or eye disease were excluded. The CCT and ACS were measured monocularly in the eye with better visual acuity using static, computer-generated, sinusoidal gratings, displayed on a high-resolution monitor. The CCT and ACS were determined using a randomized double-staircase reversal algorithm. The ACS was measured at five spatial frequencies (0.22, 0.44, 0.88, 1.75, and 3.50 cycles/degree), and the CCT was measured along red-green and tritan confusion axes. RESULTS: Red-green (P =.326) and tritan (P =.910) contrast thresholds and ACS (P >.394 for all spatial frequencies) were similar to the control group. CONCLUSIONS: Previous research suggests that prematurity adversely affects color vision and ACS. This study used a computerized psychophysical test that minimized the test errors inherent in many previous studies. Unexpectedly, CCT and ACS were found to be similar to full-term children.