N-Phenylethyl Amitriptyline in Rat Sciatic Nerve Blockade

Background: The antidepressant amitriptyline is commonly used orally for the treatment of chronic pain, particularly neuropathic pain, which is thought to be caused by high-frequency ectopic discharge. Among its many properties, amitriptyline is a potent Na+ channel blocker in vitro, has local anesthetic properties in vivo, and confers additional blockade at high stimulus-discharge rates (use-dependent blockade). As with other drug modifications, adding a phenylethyl group to obtain a permanently charged quaternary ammonium derivative may improve these advantageous properties.

Methods: The electrophysiologic properties of N-phenylethyl amitriptyline were assessed in cultured neuronal GH3 cells with the whole cell mode of the patch clamp technique, and the therapeutic range and toxicity were evaluated in the rat sciatic nerve model.

Results: In vitro, N-phenylethyl amitriptyline at 10 [mu]m elicits a greater block of Na+ channels than amitriptyline (resting block of approximately 90%vs. approximately 15%). This derivative also retains the attribute of amitriptyline in evoking high-degree use-dependent blockade during repetitive pulses. In vivo, duration to full recovery of nociception in the sciatic nerve model was 1,932 +/- 72 min for N-phenylethyl amitriptyline at 2.5 mm (n = 7) versus 72 +/- 3 min for lidocaine at 37 mm (n = 4; mean +/- SEM). However, there was evidence of neurotoxicity at 5 mm.     

The use of natural interferon alpha conjugated to a monoclonal antibody anti mammary epithelial mucin (Mc5) for the treatment of human breast cancer xenografts

Summary An immunoconjugate composed of natural interferon (nIFN) bound in a noncleavable fashion to a monoclonal antibody (MoAb) recognizing a breast epithelial membrane mucin (Mc5) was used to treat xenografts of a human mammary carcinoma cell line (MCF-7) growing in nude mice. The immunoconjugate (nIFN/Mc5) was administered as 20 intralesional (i.l.) injections to 1 of 2 xenografts in each animal. It was found that nIFN/Mc5 produced a significant enhancement of the growth inhibitory actions of nIFN on the injected tumors. Further enhancement was obtained when nIFN or nIFN together with Mc5 (at a dose 10 times larger than that present in nIFN/Mc5) were added to the immunoconjugate. Biodistribution experiments showed that the uptake of¹²⁵I-nIFN/Mc5 by the tumors was greater and its elimination slower than for¹²⁵I-nIFN alone or conjugated to irrelevant mouse IgG₁. In addition, the immunoconjugate up-regulated the antigenic expression of a breast epithelial membrane mucin by the carcinoma cells, an up-regulation which was not significantly different from that produced by nIFN alone. The contralateral noninjected tumors exposed to systemic levels of the immunoconjugate showed an enhancement of antitumor effects, but to a lesser extent than the injected tumors. These findings suggest that the enhancement of the growth inhibitory action of the immunoconjugate was related to the specific binding of Mc5 which targeted the IFN to the carcinoma cells and impeded its elimination. It is likely that the targeting was favored by the IFN-mediated up-regulation of antigenic expression by the carcinoma cells, thereby producing a cascade of interrelated effects. The results of this study point out the feasibility and potential usefulness of IFN treatment by means of immunoconjugates as well as the worth of pursuing and improving this form of therapy.     

Informed consent, parental awareness, and reasons for participating in a randomised controlled study

BACKGROUND: The informed consent procedure plays a central role in randomised controlled trials but has only been explored in a few studies on children. AIM: To assess the quality of the informed consent process in a paediatric setting. METHODS: A questionnaire was sent to parents who volunteered their child (230 children) for a randomised, double blind, placebo controlled trial of ibuprofen syrup to prevent recurrent febrile seizures. RESULTS: 181 (79%) parents responded. On average, 73% of parents were aware of the major study characteristics. A few had difficulty understanding the information provided. Major factors in parents granting approval were the contribution to clinical science (51%) and benefit to the child (32%). Sociodemographic status did not influence initial participation but west European origin of the father was associated with willingness to participate in future trials. 89% of participants felt positive about the informed consent procedure; however, 25% stated that they felt obliged to participate. Although their reasons for granting approval and their evaluation of the informed consent procedure did not differ, relatively more were hesitant about participating in future. Parents appreciated the investigator being on call 24 hours a day (38%) and the extra medical care and information provided (37%) as advantages of participation. Disadvantages were mainly the time consuming aspects and the work involved (23%). CONCLUSIONS: Parents' understanding of trial characteristics might be improved by designing less difficult informed consent forms and by the investigator giving extra attention and information to non-west European parents. Adequate measures should be taken to avoid parents feeling obliged to participate, rather than giving true informed consent.     

Safety and efficacy of interferon retreatment in children with chronic hepatitis B

More than 50% of children with chronic hepatitis B do not respond to treatment with alpha-interferon. Since these patients continue to display high viral replication and progressive liver disease, retreatment should be considered. To date it has not been well evaluated whether a second course of treatment could increase the response rate. In two alpha-interferon retreatment trials in adult patients the response rate, defined by seroconversion from HBeAg to anti-HBe, ranged between 11% and 44%. One beta-interferon retreatment study in children reported a seroconversion rate of 32%. Regrettably, none of the studies included a control group observing the `spontaneous' seroconversion rate after a first interferon cycle. Thus, a nonrandomized alpha-interferon retreatment study in children including control patients was performed. Alpha-interferon for retreatment was administered 3 times a week for 16–24 weeks in 15 children (5–16 years) at least 6 months after ceasing the first cycle. Four children received 5 MU/m² of a natural alpha-interferon and 11 children 9 MU/m² recombinant alpha-interferon 2b. Follow up was 18–47 months after initial treatment. In parallel, a control group of 19 un-retreated children with comparable clinical and demographic data was followed for 12–39 months. HBeAg seroconversion was observed in 5 (33%) of the retreated children and in 5 (26%) of the control patients during follow up. The difference is not significant. In the initially nonresponding children, those with high ALT levels before the first treatment showed late HBeAg seroconversion more frequently than those with low ALT levels (P = 0.017) irrespective of retreatment. The ALT level before retreatment was not a predictor for response. Conclusions A second cycle of alpha-interferon during the 3 years following the first treatment in nonresponding children with chronic hepatitis B can be safely performed but did not increase HBeAg/anti-HBe seroconversion compared with the spontaneous seroconversion rate of patients without retreatment. Received: 29 July 1997 / Accepted in revised form: 23 October 1997     

Long-term efficacy of subureteral collagen injection for endoscopic treatment of vesicoureteral reflux in neurogenic bladder cases

PURPOSE: We evaluated the long-term efficacy of subureteral glutaraldehyde cross-linked collagen injection (GAX 35) for endoscopic treatment of vesicoureteral reflux in patients with neurogenic bladder dysfunction due to meningomyelocele. MATERIALS AND METHODS: We prospectively studied 12 women and 8 men (26 ureteral renal units) with a median age of 8 years (range 1 to 51) who had neurogenic bladder due to meningomyelocele. Reflux into single collecting systems was treated with subureteral collagen injection (GAX 35). Followup with video urodynamics included voiding cystography. RESULTS: All patients performed intermittent catheterization to control the bladder. During the study all bladders were areflexic with normal compliance. Preoperative reflux according to the International Reflux Study Classification was grade I in 1, II in 9, III in 10, IV in 4 and V in 2 ureteral renal units. All patients were treated with subureteral collagen injection (mean volume 1.9 ml., range 0.7 to 3.5). Reflux resolved initially in all but 2 cases. Mean followup was 16 months (range 1 to 71). Reflux was still absent in only 15% of treated units after 24 months. CONCLUSIONS: Our data suggest that endoscopic subureteral collagen injection in neurogenic bladder cases is not effective with long-term followup. New biocompatible and biodegradable materials should be tested to control vesicoureteral reflux.     

Rearrangement of the T cell receptor gamma-chain gene in childhood acute lymphoblastic leukemia

We analyzed rearrangements of the T cell receptor gamma-chain (T gamma) gene as well as rearrangements of the T cell receptor beta-chain (T beta) gene and immunoglobulin heavy-chain (IgH) gene in 68 children with acute lymphoblastic leukemia (ALL). All 15 patients with T cell ALL showed rearrangements of both T beta and T gamma genes. Twenty-four of 53 non-T, non-B ALL patients (45%) showed T gamma gene rearrangements and only 14 of these also showed T beta gene rearrangements. Only a single patient rearranged the T beta gene in the absence of T gamma gene rearrangement. The rearrangement patterns of the T gamma gene in non-T, non-B ALL were quite different from those observed in T cell ALL, as 20 of 23 patients retained at least one germline band of the T gamma gene. In contrast, all T cell ALL patients showed no retention of germline bands. These data indicate that rearrangement of the T gamma gene is not specific for T cell ALL. Further, the results also suggest that T gamma gene rearrangement precedes T beta gene rearrangement. The combined analysis of rearrangement patterns of IgH, T beta, and T gamma genes provides new criteria for defining the cellular origin of leukemic cells and for further delineation of leukemia cell heterogeneity.     

Ornithine decarboxylase activity in Barrett's esophagus: a potential marker for dysplasia

Ornithine decarboxylase activity is known to be increased in certain premalignant conditions. We determined the activity of this enzyme in mucosal biopsy specimens from 15 patients with Barrett's esophagus. Ornithine decarboxylase was greater in Barrett's mucosa than in squamous esophageal or gastric mucosa. In Barrett's mucosa from 4 patients with dysplasia, the enzyme activity was greater than in 11 patients without dysplasia (1.6 +/- 0.35 vs. 0.19 +/- 0.08 U/mg protein; p less than 0.005). Increased ornithine decarboxylase activity in biopsy specimens of Barrett's mucosa may represent a marker for dysplasia.     

Liver cirrhosis in glycogen storage disease Ib

Glycogen storage disease Ib is an inborn error of carbohydrate metabolism leading to impaired glycogenolysis and gluconeogenesis. Cardinal symptoms include fasting hypoglycemia, lactic acidosis and hepatomegaly as well as neutropenia. We report for the first time on the development of liver cirrhosis in a nine-year-old boy in the course of glycogen storage disease Ib and discuss possible underlying pathomechanisms.