Quantitative evaluation of liver-specific promoters from retroviral vectors after in vivo transduction of hepatocytes

Hepatic gene therapy could be used to treat a number of inherited blood diseases such as hemophilia or thrombophilia. Although liver-directed retroviral transduction can result in long-term gene expression in vivo, the low level of protein production has limited its clinical application. We reasoned that the insertion of liver-specific promoters into retroviral vectors would increase gene expression in vivo. The 347- bp human alpha 1-antitrypsin (hAAT), the 810-bp murine albumin (mAIb), the 490-bp rat phosphoenolpyruvate carboxykinase (rPECK), and the 596- bp rat liver fatty acid binding protein promoters were inserted into a Moloney murine leukemia retroviral backbone containing the hAAT reporter gene. Vectors that produced appropriately sized RNA and hAAT protein in vitro were tested in vivo by transducing regenerating rat livers. Long-term serum expression of the hAAT reporter gene was normalized to retroviral transduction efficiency as determined by using a polymerase chain reaction-based assay of genomic DNA from transduced rat livers. The hAAT, mAIb, and rPEPCK promoters were, respectively, 35- , 8-, and 0.02-fold as strong as the previously studied constitutive Pol-II promoter. We conclude that the hAAT promoter resulted in the highest expression from a retroviral vector and may result in therapeutically significant expression of other clinically significant blood proteins.     

Assessing the delivery of neutrophils to tissues in neutropenia

Studies of neutrophil kinetics in neutropenic individuals, as well as clinical observations of variability in the occurrence of infection among patients with neutropenia, have suggested that blood neutrophil counts may not uniformly reflect the effective delivery of neutrophils to extravascular tissues where the cells perform their principal host defense functions. To evaluate this possibility we developed a sensitive, reproducible method of measuring the extravascular delivery of neutrophils to a normal mucosal site of neutrophil turnover. This method is based upon the quantification of neutrophils recoverable from saline mouth wash specimens. Twenty-five mL specimens, obtained in a controlled manner from neutropenic patients and normal subjects, were centrifuged and the sediments resuspended in 1.0 mL Hank's buffer with 2 micrograms acridine orange, incubated at 37 degrees C for 15 minutes, and then examined in a hemocytometer chamber by fluorescence microscopy. Neutrophils could be clearly distinguished by their characteristic fluorescence and were counted. With this method as few as 1,500 neutrophils were detected reliably in mouth wash specimens. Mucosal neutrophil counts varied less than 10% with repeated sampling of individual subjects over 5-day periods and were consistently greater than 1.3 X 10(5)/specimen in non-neutropenic individuals. Although profound neutropenia was generally reflected by lower than normal oral mucosal neutrophil counts, these counts were significantly higher in individuals with chronic severe neutropenia (blood neutrophils less than 300/mm3) than in patients with acute neutropenia of comparable severity that had developed following chemotherapy. Also, in individuals recovering from profound neutropenia, neutrophils usually reappeared earlier in mouth wash specimens than in blood, and oral mucosal neutrophil counts attained recovery levels more rapidly than did blood counts. This phenomenon was particularly evident in an individual with cyclic neutropenia. Moreover, mucosal neutrophils could occasionally be detected in profoundly neutropenic patients when neutrophils were not present in blood samples. These findings indicate that mucosal neutrophil counts in individuals with neutropenia provide information about the delivery of neutrophils to tissues that may not be apparent from blood neutrophil counts alone.     

Children With Chronic Pain: Response Trajectories After Intensive Pain Rehabilitation Treatment

Intensive pain rehabilitation programs for children with chronic pain are effective for many patients. However, characteristics associated with treatment response have not been well documented. In this article we report trajectories of pain and functional impairment in patients with chronic pain up to 1 year after intensive pain rehabilitation and examine baseline factors associated with treatment response. Patients (n?=?253) with chronic pain and functional disability were assessed at 5 time points (admission, discharge, 1-month, 4-month, and 12-month follow-ups). Individual trajectories were empirically grouped using SAS PROC TRAJ. For functional disability, 2 groups emerged: treatment responders (88%) and nonresponders (12%). Using a binomial logistic regression model to predict disability trajectory group, no baseline variables were significant predictors for the disability trajectory group. For pain, 3 groups emerged: early treatment responders (35%), late treatment responders (38%), and nonresponders (27%). Using multinomial regression analyses to predict pain trajectory group, older age, higher pain scores, fewer social difficulties, higher anxiety levels, and lower readiness to change were characteristics that distinguished nonresponders from responders; no significant predictors distinguished the late responders from the early responders. These results provide key information on the baseline factors that influence intensive pain rehabilitation outcomes, including risk factors that predict treatment nonresponse. Our findings have implications for developing more targeted treatment interventions.

Comparison of gastric mucosal blood flow as determined by aminopyrine clearance and gamma-labeled microspheres.

Gastric mucosal blood flow was simultaneously determined by aminopyrine clearance and gamma-labeled microspheres (15 +/- 5 mu in diameter) in anesthetized dogs prepared with a chambered segment of stomach greater curvature. Paired flow measurements were made in 11 dogs (n = 28) secreting in response to intravenous histamine (1mug per kg per min), in 11 (n = 21) nonsecreting dogs given intravenous isoproterenol (0.5 or 1.0 mug per kg per min), and in 9 (n = 10) dogs given no drugs to stimulate secretion or blood flow (resting dogs). Eight additional injections were done in dogs receiving various combinations of isoproterenol and histamine. Isotonic HCl was maintained on the mucosal surface during all experiments. Regression analysis demonstrated a highly significant linear correlation between clearance and microsphere-measured flow in the histamine (P less than 0.001, r = 0.96) and isoproterenol (P less than 0.001, r = 0.78) experiments, with clearance averaging 83% of microsphere flow during histamine stimulation but only 25% during isoproterenol. The relationship between clearance and microsphere flow was not significantly different for the resting and isoproterenol experiments. Mucosal perfusion measured by microspheres was about 5 times the resting value for both histamine and isoproterenol-stimulated dogs. Perfusion calculated from aminopyrine clearance averaged 46, 38, and 90% of the microsphere value in the resting, isoproterenol, and histamine experiments, respectively. Pooled data from secreting dogs demonstrated a fairly constant ratio of microsphere-measured flow to clearance (1.25 +/- 0.06 mean +/- SEM), regardless of the secretory rate. Our results indicate that aminopyrine clearance reflects only a small fraction of mucosal blood flow in the nonsecreting stomach, even in the presence of exogenous acid.     

Exercise-induced asthma

An acid-induced, cholinergic esophagobronchial reflex has been described whereby acid refluxing into the esophagus causes bronchospasm. Reports of exertional gastroesophageal acid reflux prompted us to study the possibility that exercise-induced asthma (EIA) could be related to gastroesophageal reflux (GER). Following an overnight fast, 10 athletes with a history of EIA (nine men, one woman; mean age 31) were studied. Continuous monitoring of intraesophageal pH and motility, ECG, and arterial oxygen saturation was done. After baseline monitoring at rest for 15 min, subjects underwent treadmill exercise for 10 min followed by continuous monitoring for 30 min after exercise. Spirometry was done at baseline prior to exercise, then repeated every 5 min after exercise for 30 min. Two subjects were retested at a later date following a standard test meal. All 10 subjects demonstrated a decrease in FEV₁ in response to exercise, but only half met criteria for EIA. Although 60% (6/10) showed some evidence of GER, only three subjects demonstrated a pathologic degree of GER. In the two subjects retested postprandially, change in FEV₁ was no different in one and improved in the other despite worsening of GER in both. There was no significant correlation between GER and EIA (P=0.2). EIA correlated inversely with amplitude of esophageal contractions (P=0.029) and was directly related to the percentage of multi-peaked contractions and the duration of peristaltic contractions (P=0.08). EIA is not associated with exertional GER.Presented at Digestive Disease Week, San Diego, California, May 16, 1995.     

Use of brachytherapy in management of locally recurrent rectal cancer

PURPOSE: Locally recurrent rectal cancer is associated with poor quality of life and has justified aggressive surgical and adjuvant approaches to control the disease. This study was designed to evaluate if the use of brachytherapy in association with wide surgical excision (debulking operation) can offer reasonable palliation for patients with locally recurrent rectal cancer. MATERIALS AND METHODS: Patients with biopsy-proven locally recurrent rectal cancer who were not candidates for intraoperative radiation therapy and who were previously considered as having unresectable tumors were included in the study and were followed-up from May 1981 to November 1990. All of them had undergone laparotomy and had either radical or debulking surgical resection performed. At the same time, brachytherapy was used with temporary or permanent implant of seeds of iridium-192 or iodine-125. RESULTS: Thirty patients were included. Patients ranged in age from 28 to 74 years, and 16 patients were female. No mortality was observed, and morbidity was low (small-bowel obstruction (1 patient), intestinal fistula (1 patient), and urinary fistula (1 patient). Histologic examination of the specimen showed gross residual disease in 67 percent of patients and microscopic disease in 25 percent of patients. Long-term follow-up was possible in 28 patients. Mean follow-up and local control were, respectively, 26.5 months and 37.5 percent for gross residual disease and 34 months and 66 percent for microscopic residual disease. Eighteen patients (64 percent) had locally recurrent rectal cancer under control at the time of the last follow-up, with seven patients (25 percent) having no evidence of local or distant recurrence. CONCLUSION: This is the first report of brachytherapy for locally recurrent rectal cancer. This appears to offer a therapeutic alternative to patients who are not candidates for intraoperative radiation therapy. Surgical morbidity and mortality are acceptable. Local control in 18 patients (64 percent) is comparable with intraoperative radiation therapy or more morbid surgical alternatives. Cancer-related deaths are most often related to disseminated disease, which suggests the need for systemic therapy in addition to brachytherapy.