Cox-2 inhibitors

Increasing pharmacy costs are among the fastest growing segments of the health care budget. Health plans are focusing on appropriately managing pharmaceutical costs, both from a long-term global perspective and a short-term approach emphasizing newly marketed products. Over the next six months, cox-2 inhibitors are expected to be approved by the FDA. This new class of drugs, investigated as a safer alternative to non-steroidal anti-inflammatory drugs (NSAIDs), is among the most highly anticipated medications to hit the marketplace. How health plans react to the launch of cox-2 inhibitors may serve as an example for future pharmacy management efforts. A proactive policy regarding the use of cox-2 inhibitors may be challenging, but should include: Reviewing clinical information; evaluating the cost of the new drug; and identifying appropriate patient selection criteria. The available management strategies include precertification, a tiered co-payment system, restricting prescriptions to a provider specialty, retrospective physician profiling, and physician education.

Reversal of a novel multidrug resistance mechanism in human colon carcinoma cells by fumitremorgin C

We selected a human colon carcinoma cell line in increasing concentrations of mitoxantrone to obtain a resistant subline, S1-M1-3.2, with the following characteristics: profound resistance to mitoxantrone; significant cross-resistance to doxorubicin, bisantrene, and topotecan; and very low levels of resistance to Taxol, vinblastine, colchicine, and camptothecin. This multidrug resistance (MDR) phenotype, which was not reversed by verapamil or another potent P-glycoprotein (Pgp) inhibitor, CL 329,753, was dependent, in part, upon an energy-dependent drug efflux mechanism. Pgp and the multidrug resistance protein (MRP) were not elevated in the resistant cells relative to the drug-sensitive parent, suggesting that resistance was mediated by a novel pathway of drug transport. A cell-based screen with S1-M1-3.2 cells was used to identify agents capable of circumventing this non-Pgp, non-MRP MDR. One of the active agents identified was a mycotoxin, fumitremorgin C. This molecule was extremely effective in reversing resistance to mitoxantrone, doxorubicin, and topotecan in multidrug-selected cell lines showing this novel phenotype. Reversal of resistance was associated with an increase in drug accumulation. The compound did not reverse drug resistance in cells with elevated expression of Pgp or MRP. We suggest that fumitremorgin C is a highly selective chemosensitizing agent for the resistance pathway we have identified and can be used as a specific pharmacological probe to distinguish between the diverse resistance mechanisms that occur in the MDR cell.

Children with autism fail to orient to naturally occurring social stimuli

Children with autism were compared to developmentally matched children with Down syndrome or typical development in terms of their ability to visually orient to two social stimuli (name called, hands clapping) and two nonsocial stimuli (rattle, musical jack-in-the-box), and in terms of their ability to share attention (following another's gaze or point). It was found that, compared to children with Down syndrome or typical development, children with autism more frequently failed to orient to all stimuli, and that this failure was much more extreme for social stimuli. Children with autism who oriented to social stimuli took longer to do so compared to the other two groups of children. Children with autism also exhibited impairments in shared attention. Moreover, for both children with autism and Down syndrome, correlational analyses revealed a relation between shared attention performance and the ability to orient to social stimuli, but no relation between shared attention performance and the ability to orient to nonsocial stimuli. Results suggest that social orienting impairments may contribute to difficulties in shared attention found in autism.

Complementary and alternative medicine. The daunting challenge

There is no question that the past few years have seen a tremendous surge in interest in what has come to be known as complementary and alternative medicine (CAM). Health plans contemplating adding CAM benefits face a daunting challenge. How should a plan define CAM benefits? How should a plan define appropriate CAM providers? How can these benefits be managed? Will the addition of CAM benefits undermine coverage policies for conventional biomedicine? The answer to these questions lies largely in uncharted waters, as even CAM advocates will agree that many alternative therapies (even those like Oriental medicine which has been in practice for some 5,000 years) have not yet undergone the type of rigorous, evidence-based analysis that is required to validate conventional biomedicine. This article explores options for CAM benefit design by considering two basic approaches-creating an uninsured benefit or insured benefit.

Prospective evaluation of magnetic resonance cholangiography to detect common bile duct stones before laparoscopic cholecystectomy

BACKGROUND

With the advent of laparoscopic cholecystectomy, endoscopic retrograde cholangiography (ERC) is frequently employed before operation to detect common bile duct stones. However, this is an invasive technique with recognized complications. This study evaluated the accuracy of magnetic resonance cholangiography (MRC) to detect choledocholithiasis in selected patients before laparoscopic cholecystectomy.

METHODS

Patients scheduled for elective laparoscopic cholecystectomy, with risk factors for common bile duct stones, underwent MRC followed by ERC or peroperative cholangiography.

RESULTS

Over a 2-year period 40 patients were studied. MRC had a sensitivity of 88 per cent, specificity of 93 per cent, positive predictive value of 78 per cent and negative predictive value of 97 per cent for the detection of common bile duct stones.

CONCLUSION

MRC is a simple non-invasive method for preoperative screening for common bile duct stones in at-risk patients. In this study it would have reduced the need for ERC by three-quarters.

Abbreviated treatment for elderly, infirm, or noncompliant patients with limited-stage small-cell lung cancer

PURPOSE

To evaluate the efficacy of an abbreviated treatment plan consisting of two cycles of chemotherapy plus thoracic irradiation in a population of limited-stage small-cell lung cancer (LSCLC) patients who were elderly, infirm, or noncompliant with standard-duration therapy.

PATIENTS AND METHODS

Fifty-five LSCLC patients (median age, 73) were treated with one cycle of cyclophosphamide, doxorubicin, and vincristine (CAV) followed 3 weeks later by one cycle of etoposide and cisplatin (EP). Both regimens were administered at conventional full dose. Thoracic irradiation (20 to 30 Gy) was delivered concurrently with EP.

RESULTS

Complete response occurred in 28 patients (51%) and partial response in 21 (38%). The median survival time was 54 weeks; the 2-year survival rate was 28% and the actual 5-year survival rate was 18%. Three patients died of toxicity.

CONCLUSION

Elderly, infirm, or noncompliant LSCLC patients who are unable to receive standard-duration chemotherapy may have useful palliation and potential for long-term survival with abbreviated chemotherapy (two cycles) and thoracic irradiation.

Sodium and ionic strength sensing by the calcium receptor

The calcium-sensing receptor (CaR) is activated by small changes in extracellular calcium [Ca2+]o) in the physiological range, allowing the parathyroid gland to regulate serum [Ca2+]o; however, the CaR is also distributed in a number of other tissues where it may sense other endogenous agonists and modulators. CaR agonists are polycationic molecules, and charged residues in the extracellular domain of the CaR appear critical for receptor activation through electrostatic interactions, suggesting that ionic strength could modulate CaR activation by polycationic agonists. Changes in the concentration of external NaCl potently altered the activation of the CaR by external Ca2+ and spermine. Ionic strength had an inverse effect on the sensitivity of CaR to its agonists, with lowering of ionic strength rendering the receptor more sensitive to activation by [Ca2+]o and raising of ionic strength producing the converse effect. Effects of osmolality could not account for the modulation seen with changes in NaCl. Other salts, which differed in the cationic or anionic species, showed shifts in the activation of the CaR by [Ca2+]o similar to that elicited by NaCl. Parathyroid cells were potently modulated by ionic strength, with addition of 40 mM NaCl shifting the EC50 for [Ca2+]o inhibition of parathyroid hormone by at least 0.5 mM. Several CaR-expressing tissues, including regions of the brain such as the subfornical organ and hypothalamus, could potentially use the CaR as a sensor for ionic strength and NaCl. The Journal guidelines state that the summary should be no longer than 200 words.

Role of the gamma chain Ala-Gly-Asp-Val and Aalpha chain Arg-Gly-Asp-Ser sites of fibrinogen in coaggregation of platelets and fibrinogen-coated beads

Fibrinogen (Fg) mediates platelet aggregation and adhesion to artificial surfaces. The carboxyl terminus of the gamma chain of Fg (residues AGDV at gamma408-411) is known to play an exclusive role in platelet aggregation, while there is no known role for the consensus RGD sites in the Aalpha chain. In this study, we used flow cytometry to measure the coaggregation (CA) of platelets with Fg-coated beads, and investigated which domains in surface-immobilized Fg support platelet adhesion. CA of platelets with Fg-beads was nearly abolished in the presence of 4A5, a monoclonal antibody (mAb) whose epitope includes AGDV, while Z69/8, a mAb that also binds to the gamma chain carboxyl terminus but does not cover AGDV, had little effect. When beads were coated with recombinant Fg (rFg) lacking AGDV, CA was similarly abolished. In contrast, beads coated with Fg that lacked the RGDS site, supported platelet CA as did intact Fg. These results were confirmed in experiments that measured the binding of activated soluble glycoprotein IIb and IIIa (GPIIbIIIa), the platelet membrane glycoprotein complex known to be the Fg receptor, to immobilized Fg. This binding was inhibited by mAb 4A5, but not by mAb Z69/8. Binding was totally retained when beads were coated with Fg lacking RGDS, but was completely lost when beads were coated with Fg lacking AGDV. These results demonstrated that the AGDV sequence on the carboxyl terminus of the gamma chain of Fg plays an exclusive role in platelet adhesion to surface-immobilized Fg, while the carboxyl terminus of the Aalpha chain, including a consensus RGD site, is not required.

Evidence for a neurotensin receptor in rat serosal mast cells

OBJECTIVE AND DESIGN

The ability of neurotensin (NT) at nmolar levels to stimulate exocytosis of the mast cell suggested that it could play a role in neuro-immune-endocrine interactions. The inhibition by a specific receptor antagonist of NT's mast cell stimulation suggested the presence of a specific mast cell NT receptor. We have here employed several probes to determine if a specific neurotensin receptor was present on rat serosal mast cells.

MATERIAL

Serosal mast cells were isolated from the peritoneal and pleural cavities of male Sprague-Dawley rats.

METHODS

Immunocytochemistry with an antibody raised against the C-terminal peptide of the neurotensin receptor was utilized. The same antibody was employed in immunoblotting following SDS gel electrophoresis of mast cell extracts. An RNA probe for ribonuclease protection assays (RPA) was prepared using the rat brain neurotensin receptor cDNA and polymerase chain reaction was carried out using primers based on the rat brain neurotensin receptor sequence.

RESULTS

Mast cells showed specific staining with the anti-neurotensin receptor antibody and this same antibody revealed a protein on SDS gels migrating as a 70 kDa species. Ribonuclease protection assays revealed the predicted protected fragment at approximately 450 bp while PCR amplification gave a major product at 843 bp.

CONCLUSIONS

These results indicate that a specific neurotensin receptor is present on the rat mast cell.

Effect of intermittent urethral catheterization and oxybutynin bladder instillation on urinary continence status and quality of life in a selected group of spinal cord injury patients with neuropathic bladder dysfunction

OBJECTIVES

A comparative assessment of (i) urinary continence status, (ii) quality of life, and (iii) sexuality in spinal cord injury patients prior to, and during intermittent catheterization with adjunctive intravesical oxybutynin therapy (Cystin: manufactured by Leiras Oy. Helsinki, Finland).

SETTING

A hospital, and community-based study of selected adult, male, spinal cord injury patients registered with the Regional Spinal Injuries Centre, Southport.

PATIENTS

Seven patients (mean age: 44.3 years) suffering from neuropathic bladder due to suprasacral spinal cord lesion of traumatic aetiology, and well settled in the community in the north-west of England were the subjects of this study. Before commencing the intermittent catheterization regime, these patients were on penile sheath drainage.

INTERVENTION

Intermittent urethral catheterization was performed with sterile, single-use Nelaton catheters 5-6 times a day with intravesical instillation of oxybutynin 5 mg in 30 ml. 1-3 times a day for periods ranging from 14 to 30 months.

OUTCOME MEASURES

Assessment of urinary continence, sexuality, and quality of life was made (i) at the outset before any intervention, (ii) during intermittent catheterization regime, and (iii) when the patients were using the oxybutynin bladder instillation along with intermittent catheterization.

RESULTS

Initially all the seven patients were constantly wearing penile sheaths and leg bags. When these patients performed intermittent catheterization 5-6 times in 24 h, they attempted to discard the penile sheath during the day but they were experiencing mild to moderate urine leak between catheterization. They were compelled to wear penile sheaths during night. Subsequently, five patients took oxybutynin by mouth, but developed an unacceptable degree of side-effects necessitating discontinuation of the medication. Following commencement of intravesical oxybutynin therapy, all of them were able to discard the penile sheaths and leg bags during the day as well as during the night. However, on waking-up after a full night's sleep, three patients found dampness of their undergarments 1-2 times per week. None of the patients experienced side-effects attributable either to the intermittent catheterization procedure, or to the intravesical oxybutynin therapy. The number of episodes of urinary infection requiring antibiotic therapy was 0.08/patient/month. All the seven patients noticed a remarkable improvement in the quality of life because they had achieved a high degree of continence. All the seven patients commented on the improved sense of their own sexuality which was attributed to (i) absence of incontinence episodes, (ii) improved self-image, and (iii) not wearing penile sheaths and leg bags.

CONCLUSION

These seven spinal cord injury patients achieved socially acceptable continence with improved quality of life, and enhanced sexuality with the intermittent urethral catheterization regime and intravesical oxybutynin therapy.

Primary structure of ovine fibroblast growth factor-1 deduced by protein and cDNA analysis

The amino acid sequence of full-length ovine fibroblast growth factor-1 (FGF-1) was determined by a combination of protein and cDNA sequencing. FGF-1 cDNA analysis indicated that ovine kidney cells express mRNAs encoding both full-length FGF-1 and a truncated FGF-1 variant. An overall comparison of the ovine FGF-1 primary sequence to the eight species studied to date revealed a high degree of conservation, with ovine FGF-1 sharing 90 and 95% sequence identity with human FGF-1 and bovine FGF-1, respectively. Additionally, the FGF-1 proteins from the various species have conserved cysteine residues at positions 30 and 97 and contain acetylated amino-terminal alanine residues. Mass spectrometry analysis confirmed that the blocking group of ovine FGF-1 is also consistent with that of an acetyl-moiety. In contrast to the other FGF-1 proteins, the 154 residue primary sequence of ovine FGF-1 contains three unique amino acid differences: Arg9, Arg44, and Ile123. Ovine FGF-1, unlike human FGF-1, is a potent mitogenic factor for NIH 3T3 fibroblasts in the absence of heparin. In the presence of exogenous heparin, the mitogenic activity of ovine FGF-1 is potentiated slightly.

Strategies for environmental monitoring of toxin producing phantom dinoflagellates in the Chesapeake

Toxin-producing estuarine dinoflagellates have been linked with the occurrence of fish kills and the development of a novel clinical illness syndrome among persons exposed to waters during fish kill events. The prototype organism of this group, Pfiesteria piscicida, has an extremely complex life cycle, making traditional methods used for environmental monitoring of harmful algal blooms less reliable. The response to fish kill events and the occurrence of human illness in Maryland in 1997 is reviewed, with particular emphasis on problems in organism detection. Current and anticipated classical and molecular methodologies for the detection of Pfiesteria and Pfiesteria-like organisms are reviewed. Development of these capabilities will be of critical importance in defining the epidemiology of human illness related to environmental exposure to Pfiesteria, and in developing public health strategies to predict and prevent such illness.

In vitro activity of hepatitis B virus polymerase: requirement for distinct metal ions and the viral epsilon stem-loop

Hepadnaviruses have a complex replication cycle which includes reverse transcription of the pregenomic RNA. The initial step in this process in hepatitis B virus (HBV) requires the viral polymerase to engage a highly stable region of secondary structure within the pregenomic RNA termed the epsilon stem-loop. While reverse transcriptases belonging to the retrovirus family use a specific cellular tRNA as primer, HBV polymerase utilizes a tyrosine residue located within its own N terminus. Therefore, the first deoxyribonucleotide is covalently coupled to HBV polymerase prior to extension of the DNA strand by conventional reverse transcription. We have expressed HBV polymerase in a baculovirus and following purification have found it to be active with respect to protein-priming and reverse transcription of copurified RNA. Importantly, we found both of these processes to be critically dependent on the presence of the epsilon stem-loop. The metal ion preferences of HBV polymerase were also investigated for both the protein-priming and reverse transcription activities of this enzyme. Reverse transcription was dependent on magnesium, with an optimal concentration of 5 mM. However, protein-priming was strongly favoured by manganese ions and was optimal at a concentration of 1 mM. Thus, using manganese as sole source of metal ions our activity assay is restricted to the protein-priming event and will allow the search for novel antivirals specifically blocking this unique mechanism.

"Depression" increases "craving" for sweet rewards in animal and human models of depression and craving

This study consisted of two experiments, one in rats and one in human volunteers, that used the identical progressive ratio (PR) operant procedure. In both experiments, responding was reinforced under a progressively increasing work requirement, and different groups of subjects received reinforcers that varied in sweetness. In experiment 1, rats were subjected to chronic mild stress, a well-validated animal model of depression. Performance under the PR schedule increased in subjects reinforced with conventional precision pellets (which contain 10% sucrose) or very sweet pellets, but not in subjects reinforced with sugar-free pellets. In experiment 2, volunteers were subjected to a depressive musical mood induction. Performance under the PR schedule increased in subjects reinforced with chocolate buttons, but not in subjects reinforced with with buttons made from the relatively unpalatable chocolate substitute carob. In experiment 2, depressive mood induction also increased chocolate craving, as measured by a novel questionnaire, and there were significant correlations between chocolate craving and chocolate-reinforced PR performance. These results suggest that performance under the PR schedule provides a measure of craving rather than reward, and that craving for sweet rewards is increased by depressive mood induction in both animal and human models. Implications for the interpretation of pharmacological studies using the PR procedure are also discussed.

The AGDV residues on the gamma chain carboxyl terminus of platelet-bound fibrinogen are needed for platelet aggregation

It has been clear that only the carboxyl terminus of fibrinogen (Fg) gamma chain is required for the initial binding of Fg from solution to its GPIIbIIIa (glycoprotein IIb and IIIa) receptor on activated platelets, whereas the two RGD sites on the A alpha chain do not play any role. In this study, we examined the role of these three putative adhesive domains on Fg already bound to its receptors in mediating platelet aggregation. Activated platelets were first incubated with Fg to let the Fg bind, then with monoclonal antibodies (mAb) to block the putative adhesive domains, and the platelet suspension was then sheared or stirred to induce aggregation. The mAb 4A5, which recognizes the last four amino acid residues (AGDV) in a dodecapeptide (H12) on the carboxyl terminus of the Fg gamma chain, markedly inhibited platelet aggregation. Z69/8, a mAb whose epitope is also on the dodecapeptide but does not recognize the AGDV residues, did not have any inhibitory effect on aggregation. The anti-RGDS and anti-RGDF mAbs did not affect both macro- and micro-aggregation at all, whether tested singly or together. These results demonstrate that, similar to the situation for the initial binding of soluble Fg, only the gamma chain carboxyl terminus with the AGDV residues are needed for platelet-bound Fg to support aggregation, while the RGD sites on the A alpha chain do not seem to be required.

Successful pregnancy outcome after hysteroscopic adhesiolysis in Asherman's syndrome

Asherman's syndrome is an uncommon finding at hysterosalpingography for infertility. Modern day management entails hysteroscopic confirmation and adhesiolysis. We present one such case of a young woman who had secondary infertility after dilatation and curettage, and who was diagnosed and treated with a successful outcome.

Neurotrophins stimulate chemotaxis of embryonic cortical neurons

During mammalian cortical development, neuronal precursors proliferate within ventricular regions then migrate to their target destinations in the cortical plate, where they organize into layers. In the rat, most cortical neuronal migration occurs during the final week of gestation (Bayer et al, 1991; Jacobson, 1991). At this time (E15-E21), reverse transcriptase-polymerase chain reaction demonstrated that cortical homogenates contain mRNA encoding brain derived neurotrophic factor (BDNF) and the catalytic form of its high-affinity receptor, TrkB. Immunocytochemistry and in situ hybridization of sections revealed that the catalytic TrkB receptors predominantly localize to regions containing migratory cells. Many TrkB+ cells exhibited the classic morphology of migrating neurons, suggesting that TrkB ligands play a role in cortical neuronal migration. We analysed whether TrkB ligands influence the motility of embryonic cortical cells (from E15-E21) using a quantitative in vitro chemotaxis assay. High-affinity TrkB ligands (BDNF and NT4/5) stimulated chemotaxis (directed migration) of embryonic neurons at concentrations ranging from 1 to 100 ng/ml. NT-3, a low-affinity TrkB ligand, only stimulated significant migration at high concentrations (> or =100 ng/ml). Peak migration to BDNF was observed at gestational day 18 (E18). BDNF-induced chemotaxis was blocked by either tyrosine kinase inhibitor, K252a, or the Ca2+-chelator, BAPTA-AM, suggesting that BDNF-induces motility via autophosphorylation of TrkB receptor proteins and involves Ca2+-dependent mechanisms. BDNF-stimulation of increased cytosolic Ca2+ was confirmed with optical recordings of E18 cortical cells loaded with Ca2+ indicator dye. Thus, signal transduction through the TrkB receptor complex directs neuronal migration, suggesting that, in vivo, BDNF exerts chemotropic effects that are critical to morphogenesis of the cortex.

Neutrophil adhesion and the therapy of inflammation

Cell adhesion has an essential role in neutrophil recognition of sites of inflammation, migration through endothelium and extracellular matrix, and activation to full effector function at these sites. Adhesion molecules on the neutrophil involved in these events include members of the selectin, integrin, and immunoglobulin superfamilies. Inhibition of neutrophil adhesion holds the promise of interrupting idiopathic inflammation in a variety of diseases, but also can increase susceptibility to infection. The therapeutic challenge is to design agents of sufficient specificity to block the deleterious effects of neutrophil influx and activation without interference with host defense. This will require improved understanding of the molecular events regulating, and regulated by, neutrophil adhesion.

The Ca2+-sensing receptor: a target for polyamines

The Ca2+-sensing receptor (CaR) is activated at physiological levels of external Ca2+ (Ca(o)) but is expressed in a number of tissues that do not have well-established roles in the control of Ca(o), including several regions of the brain and the intestine. Polyamines are endogenous polyvalent cations that can act as agonists for the CaR, as shown by our current studies of human embryonic kidney (HEK-293) cells transfected with the human CaR. Cellular parameters altered by polyamines included cytosolic free Ca2+ (Ca(i)), inositol phosphate production, and the activity of a nonselective cation channel. Spermine stimulated Ca(i) transients in CaR-transfected HEK cells, with a concentration producing a half-maximal response (EC50) of approximately 500 microM in the presence of 0.5 mM Ca2+, whereas sustained increases in Ca(i) had an EC50 of approximately 200 microM. The order of potency was spermine > spermidine >> putrescine. Elevation of Ca(o) shifted the EC50 for spermine sharply to the left, with substantial stimulation below 100 microM. Addition of subthreshold concentrations of spermine increased the sensitivity of CaR-expressing HEK cells to Ca(o). Parathyroid hormone secretion from bovine parathyroid cells was inhibited by 50% in the presence of 200 microM spermine, a response similar to that elicited by 2.0 mM Ca(o). These data suggest that polyamines could be effective agonists for the CaR, and several tissues, including the brain, may use the CaR as a target for the actions of spermine and other endogenous polycationic agonists.

Frontal functions in juvenile myoclonic epilepsy

The authors investigated cognition in juvenile myoclonic epilepsy (JME), focusing on frontal functions as suggested by maximal spatial distribution of epileptiform activity seen over frontocentral regions. Fifteen patients with JME (mean age, 34.3 years; mean estimated IQ 101) were administered a battery of tests sensitive to frontal dysfunction. The number of patients with impaired test performance and the frequency of impairment per test were calculated. Performance on selected tests was compared with that of 15 patients with temporal lobe epilepsy (TLE) who were matched for estimated IQ using paired t-tests. Although the performance of the group with JME was not uniform--some patients showed marked impairment whereas others showed little or no deficit--a high frequency of impairment was found on tests of concept formation-abstract reasoning and mental flexibility, cognitive speed, and planning and organization. Significant differences were found between the group with JME and the group with TLE on tests requiring mental flexibility and concept formation-abstract reasoning. In conjunction with studies demonstrating intractable seizures in approximately 20% of patients, the results from this study suggest that JME is not a uniformly benign condition. Frontal deficits may have maladaptive behavioral consequences suggestive of personality dysfunction, as described anecdotally by previous investigators.