The ras and myc oncogenes cooperate in tumor induction in many tissues when introduced into midgestation mouse embryos by retroviral vectors

Midgestation embryos were infected with replication-defective retroviral vectors that either transduced the myc oncogene, the ras oncogene, or both oncogenes simultaneously. The myc virus induced tumors in diverse organs at a very low frequency and with a long latency period, while approximately 20% of the mice derived from embryos infected with the ras virus developed tumors in the skin with a latency of 4-8 weeks. In contrast, infection of embryos with the ras/myc double oncogene virus resulted in 27% of the animals developing rapidly growing and malignant tumors in a great variety of tissues after a median latency period of 2-3 weeks. All tumors were of monoclonal origin, as shown by Southern analysis using the provirus as a molecular marker. Our results are consistent with the hypothesis that the ras and myc oncogenes cooperate in transforming cells, but that additional alterations are necessary for realization of the fully malignant phenotype. Our observations also suggest that a much wider range of cell types become targets for malignant transformation when the embryos are exposed to the myc and the ras oncogenes simultaneously than when exposed to the same oncogenes separately. Infection of mouse embryos with vectors carrying different oncogenes or oncogene combinations may be an efficient and rapid method for evaluating the spectrum of cell types at risk for malignant conversion following mutation of a protooncogene to a transforming gene.

Treatment of pulmonary manifestations of gastroesophageal reflux in children two years of age or less

Apnea and worsening bronchopulmonary dysplasia as well as recurrent aspiration pneumonia have been found to be consequences of gastroesophageal reflux in infants and young children. Antireflux procedures are effective in preventing gastroesophageal reflux; however, the effect of this operation on the course of these respiratory problems in very young patients is not known. We reviewed the results in 51 patients 2 years of age or less who underwent an antireflux fundoplication for pulmonary problems attributable to severe gastroesophageal reflux unresponsive to medical treatment. Twenty-eight patients had recurrent episodes of aspiration pneumonia, 14 had nonimproving or worsening bronchopulmonary dysplasia, and 9 had unexplained apneic episodes. Seventy-three percent of these patients had coexisting congenital anomalies or acquired problems. No operative deaths and no major surgical complications occurred. There were eight late deaths occurring between 1 and 25 months postoperatively: three were due to associated congenital anomalies or acquired problems, three to sepsis, and two to sudden infant death syndrome. Of the 43 surviving children, 91 percent with preoperative recurrent aspiration pneumonia had no additional episodes after Nissen procedure. Eighty-eight percent of the infants with unexplained apneic episodes showed marked benefit and 83 percent of those with bronchopulmonary dysplasia had clinical improvement. There were no late problems attributed to the operation even when it was performed in preterm infants. Therefore, we recommend fundoplication for patients 2 years of age or less who have a persistent pulmonary problem attributed to gastroesophageal reflux that does not respond to medical therapy.

Interaction of reinforcement history with methadone on responding maintained under a fixed-interval schedule

Twelve pigeons were initially trained under either a fixed-ratio (FR) 50 or differential-reinforcement-of-low-rate (DRL) 10-sec schedule of food presentation. After 50 sessions of exposure to the foregoing schedules all pigeons key pecked under a fixed-interval (FI) 90-sec schedule. Key-peck rates differed as a function of schedule history, with FR-history subjects responding at significantly higher rates under the FI schedule than DRL-history subjects. To better compare methadone's rate-altering effects on baseline response rates, 8 naive pigeons were trained from the outset to key peck under an FI 90-sec schedule and were subsequently divided into 2 groups based on overall response rates (groups FI-H and FI-L). After at least 40 sessions under the FI schedule methadone dose-response curves were determined at doses of 0.6, 1.2 and 2.4 mg/kg. Low and intermediate methadone doses did not effect key-peck rates by pigeons with an FR history compared to significant rate decreases by pigeons having comparable rates but without a history of responding under an FR schedule (group FI-H). No differential effects following methadone were observed in low-rate subjects (DRL history and FI-L). When methadone (9.0 and 12.0 mg/kg/day) was administered chronically, response rates of all subjects were initially suppressed, with FI control subjects showing more complete recovery of drug-free baselines than either FR- or DRL-history groups. Naloxone (1.0 mg/kg) reversed methadone's rate-decreasing effects, although these actions were significantly less in subjects with prior experience under DRL schedules. Following completion of the chronic phase, and when subjects had been drug free for at least 14 sessions, the methadone dose-response curve was redetermined. The differential effects of methadone associated with reinforcement history were no longer evident, suggesting that a drug history can interact with a schedule history. These experiments add to the growing body of evidence indicating that prior experience can influence the behavioral actions of drugs independent of control rate of responding. Moreover, the data reveal that the influence of reinforcement schedule history depends on whether drugs are administered acutely or chronically.

Effects of buprenorphine, methadone and naloxone on acquisition of behavioral chains

Buprenorphine, methadone and naloxone were administered to pigeons key pecking under a repeated acquisition procedure. Under this procedure subjects are required to emit a new sequence of responses each session to receive access to food. All three drugs reduced overall key pecking rates although naloxone's rate-reducing effect was limited to the highest dose (30 mg/kg). The dose-effect curves for overall key pecking rate under buprenorphine and methadone were similar though the effective dose range for buprenorphine appeared wider. Methadone increased percentage of total errors at the highest doses, but neither buprenorphine nor naloxone affected total error levels very much. Within-session errors were increased early in the session under high methadone doses. Low buprenorphine doses also showed some tendency to increase errors early in the session. Buprenorphine and methadone reduced the number of chains completed in a dose-dependent manner. Buprenorphine was also administered daily at the most behaviorally disruptive dose (10 mg/kg/day). Under this dosing schedule, the behavior-suppressing effects of buprenorphine returned to base-line levels within 4 days. Error rates were unaffected by daily buprenorphine administration.

Therapeutic options in IgA nephropathy

IgA nephropathy (IgAN) is a common form of glomerulonephritis that leads to end-stage renal disease at variable rates in 20% to 30% of cases. A rational approach to therapy requires an understanding of pathogenetic mechanisms that are largely unknown. Several therapeutic approaches have been used, generally in uncontrolled trials, aimed at lowering levels of circulating immune complexes, affecting cellular immunity, or removing antigens through dietary restriction. Thus far, no clear-cut beneficial effects are evident. Alternative means of changing glomerular hemodynamics through prevention of harmful mediators await exploration.

Chromatin structure of hormone-responsive Moloney murine leukemia virus proviruses that contain sequences from mouse mammary tumor virus

The chromatin structure of chimeric Moloney murine leukemia viruses (M-MuLVs) containing a glucocorticoid response element (GRE) from mouse mammary tumor virus (MMTV) inserted into the long terminal repeat (LTR) was investigated. Nuclear run-on assays indicated that transcription from the chimeric proviruses was induced 2- to 4-fold by dexamethasone. The wild-type M-MuLV 5' LTR contained a DNase I hypersensitive (HS) site at the TATA sequences, as well as four sites in the enhancer region. The chimeric LTRs contained these sites, as well as three additional sites in the MMTV sequences. Two of the MMTV sites were present in the absence of hormone, while one was hormone-induced. In addition, internal MMTV sequences appeared protected from DNase I digestion in the absence of hormone, suggesting bound protein. Hormone treatment resulted in loss of the DNase I protection.

Congenital adrenal hypoplasia and selective absence of pituitary luteinizing hormone: a new autosomal recessive syndrome

Congenital hypoplasia of the adrenal glands (CHA) is a rare condition, particularly in the absence of a central nervous system (CNS) anomaly. Two major types of CHA have been described in the setting of an apparently normal CNS and pituitary: a cytomegalic type usually with X-linked recessive inheritance and a miniature adult type that, when hereditary, is an autosomal recessive trait. Glycerol kinase deficiency (GKD) is an X-linked recessive trait, and it may be associated with CHA and adrenal insufficiency, presumably because of deletion of adjacent X-linked loci. We report on three sibling infants, one male and two females, with normal CNS and lethal CHA of the miniature adult type, selective absence of pituitary LH; two of the infants also had glycerol kinase (GK) activity that was decreased but not in the GKD range. Restriction fragment length polymorphism (RFLP) analysis of X chromosome markers located at Xp21-p22 was carried out on the maternal grandfather, both parents, two of three affected infants, and a living normal brother. The results excluded the X-linked type of this disorder associated with GKD in this family. Autosomal recessive inheritance is most likely.

Multimodality treatment of non-small cell lung cancer: response to cisplatin, VP-16, and 5-FU chemotherapy and to surgery and radiation therapy

Twenty-one patients with unresectable non-small cell lung cancer (NSCLC), 11 with stage III M0, five with malignant pleural effusion, and five with a single resectable metastasis were treated with multimodality therapy. All received two to three cycles of preoperative chemotherapy with a new sequential combination of cisplatin (50 mg/m2 IV X 1) followed by 5-FU infusion (40 mg/m2/hr X 72) and etoposide (80 mg/m2/day X 3). Thirteen of 21 (62%) had a partial response, and three (14%) had a minor response to chemotherapy. Of the 19 who underwent surgical exploration, 17 were confirmed to have NSCLC. Ten patients with NSCLC and one with choriocarcinoma were rendered disease free by resection of the primary tumor and lymph nodes. Six received intra- and/or perioperative interstitial therapy with 125I and/or 192Ir. Another patient was treated with 32P. Postoperative external radiotherapy was administered in 15 patients, and adjuvant chemotherapy was administered in ten. This multimodality therapy was well tolerated, safe, and highly effective, resulting in excellent palliation even in patients with pleural effusion and metastasis. The most promising results were in unresectable stage III M0 with a partial response rate of 82% following neoadjuvant chemotherapy and a complete response rate of 73% after surgery. In this group, median survival has not yet been reached and will exceed 12 months.

Methodological considerations in enuresis-treatment research. A three-treatment comparison

Three treatments for enuresis were evaluated: (a) immediate detection with a urine-sensing alarm with additional operant training procedures, (b) delayed detection with staff activating the alarm and conducting the procedures in the morning, and (c) yoked-schedule awakenings when the awakening times were determined by the performance of a randomly matched participant from the immediate-detection group. Twenty seven people with mental retardation (most profoundly or severely handicapped), whose ages ranged from 13 to 29 years, participated. Nine of the participants were noncompliant with the linen changing and practice walks to the bathroom and thus did not receive consistent treatment. All 7 of the compliant members of the immediate-detection group improved, 2 of the delayed-detection group worsened while 2 improved, and 6 of 7 yoked awakenings participants improved. Improvement negatively correlated with the frequency of baseline bed-wetting. Several methodological issues are raised concerning enuresis treatment.

Food deprivation and methadone effects on fixed-interval performance by pigeons

Five adult male White Carneaux pigeons, maintained at approximately 70, 80 or 90% free-feeding weight, were administered methadone (0.5, 1.5, and 2.5 mg/kg) prior to sessions of key pecking maintained under 5-min fixed-interval schedules of food presentation. Increasing deprivation levels attenuated the rate-decreasing effects of methadone. Methadone effects on pause time were unchanged. Three pigeons, maintained at 80% free-feeding weight were then administered methadone hydrochloride (0.62, 1.25 and 2.5 mg/kg) and naloxone hydrochloride (.0001, .0003, .001, .003 or .01 mg/kg) alone and in combination while responding under these same contingencies. Naloxone had no systematic behavioral effects alone but antagonized methadone's effects on fixed-interval responding and pausing. Naloxone also altered methadone's rate-dependent effects. These results suggest the behavioral effects of methadone are differentially altered following food-deprivation and opiate antagonist manipulations.

Interaction of methadone, reinforcement history, and variable-interval performance

In the present study, we examined how a reinforcement schedule history that generated high or low rates of responding influenced the effects of acute (Experiment 1) and chronic (Experiment 2) methadone administration. Initially, key-peck responses of pigeons were maintained under a variable-interval 90-s schedule of food presentation, and a methadone dose-response curve was determined with doses of 0.6, 1.2, and 2.4 mg/kg. The pigeons were then exposed, for at least 40 sessions, to either a fixed-ratio 50 schedule or a differential-reinforcement-of-low-rate 10-s schedule, or were given continued exposure to the variable-interval schedule. The methadone dose-response curve was redetermined after all pigeons again were responding under the variable-interval schedule. The effects of two different daily methadone doses (9.0 and 12.0 mg/kg/day) and withdrawal precipitated by naloxone also were assessed. Experience with a fixed-ratio or differential reinforcement of low rate schedule did not result in significantly different response rates under the variable-interval schedule and, in general, the acute effects of methadone did not have differential effects correlated with schedule history. However, for 2 of 4 subjects the rate-decreasing effects of methadone on rates of key pecking were greater following a history of low-rate responding, suggesting a possible interaction between schedule history and effects of methadone. Daily methadone administration under the variable-interval schedule revealed that pigeons with experience under the differential reinforcement of low rate schedule developed more rapid and complete tolerance to the rate-decreasing effects of methadone. Three of the 4 subjects in this group showed rate increases above drug-free baselines during chronic methadone dosing. Pigeons with a history of fixed-ratio responding also developed tolerance to the rate-decreasing effects of methadone but without the subsequent rate increases seen by subjects with low-rate histories. No subjects with variable-interval histories showed complete recovery of drug-free baselines, suggesting that interpolated training under other schedules may attenuate the rate-altering effects of chronically administered drugs. Naloxone (1.0 mg/kg), administered during the chronic methadone phase, resulted in greater disruption of responding by pigeons with a history of low-rate responding, as compared to subjects in the other two groups.(ABSTRACT TRUNCATED AT 400 WORDS)

An animal model of the interpersonal communication of interoceptive (private) states

Pigeons were taught to interact communicatively (i.e., exchange discriminative stimuli) based on 1 pigeon's internal state, which varied as a function of cocaine, pentobarbital, and saline administration. These performances generalized to untrained pharmacological agents (d-amphetamine and chlordiazepoxide) and were observed in the absence of aversive stimulation, deprivation, and unconditioned reinforcement. The training procedure used in this study appears similar to that by which humans learn to report on (tact) their internal environments and may be construed as a rudimentary animal model of the interpersonal communication of private events.

Splenic hemangioma with thrombocytopenia in a newborn

The case report of a newborn infant with a splenic hemangioendothelioma with the life-threatening complications of thrombocytopenia, anemia, and disseminated intravascular coagulation is presented together with a review of the literature. Removal of the tumor via splenectomy, despite the known risk of subsequent overwhelming sepsis due to encapsulated organisms in the young child, is the treatment of choice for splenic hemangiomas complicated by thrombocytopenia. The use of enhanced CT with delayed filling is a diagnostic tool in the workup of suspected hemangiomatous lesions.

The effect of a low protein diet with amino acid/keto acid supplements on glucose metabolism in children with uremia

Six children with chronic renal failure were treated with dietary protein restriction and essential amino acid and keto acid supplements for 6 months. Dietary protein and phosphate intake decreased, dietary calcium increased, and dietary carbohydrate and energy did not change. Plasma urea and urea to creatinine ratio decreased significantly during treatment. Glucose metabolism was studied before and after 6 months of treatment using the hyperglycemic clamp technique. Fasting hyperglycemia, glucose intolerance, and insulin resistance improved during treatment, while fasting insulin and insulin levels during hyperglycemia did not change. These metabolic changes were not related to hyperparathyroidism and were probably due to reduction in nitrogen toxicity.

Asynchronies of diphenhydramine plasma-performance relationships

The relation between performance on driving-related tasks and plasma levels of diphenhydramine was studied in eight male volunteers over 24 hours following oral administration. DPH plasma concentrations rose to peak levels in 1.5-2.5 hours varying with dose, declining to a nearly constant level by 12-24 hours. For all behavioral measures, the shape of performance curves over time was similar to that of plasma, reaching maximum decrements in 1-4 hours. The relation between plasma levels and performance was asynchronous varying with behavioral measure and dose. The use of plasma DPH values to predict performance decrements is limited due to the bivalued nature of these relationships in time. Nonetheless, it would appear that if DPH is administered in the therapeutic dosage range at the intervals typically recommended for cold symptoms and allergies, it appears some aspects of human performance may be impaired.