Pharmacology of INS37217 [P(1)-(uridine 5')-P(4)- (2'-deoxycytidine 5')tetraphosphate, tetrasodium salt], a next-generation P2Y(2) receptor agonist for the treatment of cystic fibrosis

INS37217 [P(1)-(uridine 5')-P(4)-(2'-deoxycytidine 5')tetraphosphate, tetrasodium salt] is a deoxycytidine-uridine dinucleotide with agonist activity at the P2Y(2) receptor. In primate lung tissues, the P2Y(2) receptor mRNA was located by in situ hybridization predominantly in epithelial cells and not in smooth muscle or stromal tissue. The pharmacologic profile of INS37217 parallels that of UTP, leading to increased chloride and water secretion, increased cilia beat frequency, and increased mucin release. The combined effect of these actions was confirmed in an animal model of tracheal mucus velocity that showed that a single administration of INS37217 significantly enhanced mucus transport for at least 8 h after dosing. This extended duration of action is consistent with the ability of INS37217 to resist metabolism by airway cells and sputum enzymes. The enhanced metabolic stability and resultant increased duration of improved mucociliary clearance may confer significant advantages to INS37217 over other P2Y(2) agonists in the treatment of diseases such as cystic fibrosis.

Quantification of histologic regression of rectal cancer after irradiation: a proposal for a modified staging system

PURPOSE

Long-course preoperative radiotherapy has been recommended for rectal carcinoma when there is concern about the ability to perform a curative resection, for example, in larger tethered tumors or those sited anteriorly or near the anal sphincter. "Downstaging" of the tumor may occur, and this is of importance when estimating the prognosis and selecting postoperative therapy for patients. We studied the effects of preoperative chemoradiotherapy on the pathology of rectal cancer, and we propose a simplified measurement of tumor regression, the Rectal Cancer Regression Grade.

METHODS

We have reviewed those patients who received preoperative chemoradiotherapy followed by surgical resection for carcinomas of the mid or distal third of the rectum found to be Stage T3/4 on transrectal ultrasound or CT between January 1995 and December 1998. Patients received 45 to 50 Gy irradiation and an infusion of 5-fluorouracil. The surgical specimens were examined by one pathologist, and the Rectal Cancer Regression Grade was quantified.

RESULTS

Forty-two patients, mean age 60 (range, 42-86) years, underwent chemoradiotherapy before surgery for rectal carcinoma. There were 28 anterior resections (67 percent; 9 with a colonic pouch), 12 abdominoperineal resections (27 percent), and 2 Hartmann's procedures (5 percent). Comparison of preoperative and pathologic staging revealed that the depth of invasion was downstaged in 17 patients (38 percent), and the status of involved lymph nodes was downstaged in 13 (50 percent) of 26 patients. Tumor regression was more than 50 percent (Rectal Cancer Regression Grades 1 and 2) in 36 patients (86 percent), with 7 patients (17 percent) having complete regression with absence of residual cancer cells.

CONCLUSION

Significant tumor regression was seen in 86 percent of cases after chemoradiotherapy, with 19 patients showing a "good" responsiveness. We propose a modified pathologic staging system for irradiated rectal cancer, the Rectal Cancer Regression Grade, which includes a measurement of tumor regression. The utility of the proposed Rectal Cancer Regression Grade must be tested against long-term outcomes before its value in predicting prognosis and survival can be determined.

A nurse-delivered advice intervention can reduce chronic non-steroidal anti-inflammatory drug use in general practice: a randomized controlled trial

OBJECTIVE

To find out whether a nurse-delivered educational package can reduce chronic oral non-steroidal anti-inflammatory drug (NSAID) usage in general practice.

METHOD

A prospective randomized controlled trial with assessment of economic cost/benefits was carried out in five general practices in Nottinghamshire with computerized prescribing systems, representing a mix of rural/urban and fundholding/non-fundholding practices. Patients suffering from non-malignant, non-inflammatory musculoskeletal pain received repeat prescriptions for oral NSAIDs. Two hundred and twenty-two patients were randomized to a control group (simple advice regarding NSAID use) or an intervention group (asked to withdraw their NSAIDs and employ appropriate alternative drug and non-drug therapies). All advice was supported by patient literature and delivered by a nurse practitioner trained in musculoskeletal assessment. The primary outcome measure was change in NSAID use 6 months after the intervention. Secondary outcome measures were changes in health and quality of life (SF-36 and EQ-5D questionnaires) and drug, health service and patient costs.

RESULTS

An extra 28% of patients in the intervention group either stopped taking oral NSAIDs or reduced dosage by > or =50% at 6 months compared with controls. There was no detrimental effect on health and well-being. Oral NSAID prescription costs were significantly lowered in the intervention group but not in the control group. A non-significant increase in total drug prescription costs occurred in both groups.

CONCLUSIONS

Nurse-based intervention can reduce chronic NSAID usage and costs in primary care and would be cost-effective if maintained in the long term. This intervention package would be readily applicable in primary care.

Primary extracranial meningioma of the mandible: A report of 2 cases and a review of the literature

Three cases of primary extracranial meningioma arising in the jaws have been reported in the English-language literature. The purpose of this report is to document 2 additional cases that arose in the mandible. Both cases occurred in women and appeared as radiolucent lesions. Microscopic examination revealed an unencapsulated tumor composed of uniform spindle-shaped cells arranged in whorls and interconnecting fascicles. Occasional nuclear pseudoinclusions and psammoma bodies were identified. The tumor cells demonstrated immunohistochemical reactivity for epithelial membrane antigen and vimentin. Both cases were treated by surgical excision. Based on previously published examples in the jaws, these neoplasms do not appear to be aggressive.

Cooperativity between KorB and TrbA repressors of broad-host-range plasmid RK2

The KorB and TrbA proteins of broad-host-range plasmid RK2 are key regulators of the plasmid genes required for conjugative transfer. trbBp is the primary promoter responsible for expression of mating pair formation genes. We show that despite the targets for KorB and TrbA at trbBp being about 165 bp apart, 189 bp upstream of the transcription start point and overlapping the -10 region, respectively, these two proteins show up to 10-fold cooperativity for the repression of trbBp. Deletion analysis of TrbA showed that the C-terminal domain (CTD), which has a high degree of sequence conservation with the CTD of KorA, is required for this cooperativity with KorB. Western blotting demonstrated that the apparently mutual enhancement of repression is not due simply to elevation of repressor level by the presence of the second protein, suggesting that the basis for cooperativity is interaction between KorB and TrbA bound at their respective operators.

Application and evaluation of denaturing HPLC for molecular genetic analysis in tuberous sclerosis

Tuberous sclerosis (TSC) is an autosomal dominant disorder characterised by the development of hamartomas in multiple tissues and organs. TSC exhibits locus heterogeneity with genes at 9q34 (TSC1) and 16p13.3 (TSC2) that have 21 and 41 coding exons, respectively. The mutational spectrum at both loci is wide and previous studies have shown that 60%-70% of cases are sporadic and represent new mutations. We have formatted denaturing high performance liquid chromatography (DHPLC) for rapid screening of all coding exons of TSC1 and TSC2. DHPLC analysis detected likely disease-causing mutations in 103 of 150 unrelated cases (68%), compared with 92/150 (61%) and 87/150 (58%) for single-strand conformation polymorphism analysis (SSCP) and conventional heteroduplex analysis (HA), respectively. Capital, consumable and labour costs were determined for each exon screening procedure. Estimated costs per patient sample depended on throughput, particularly for DHPLC, where a high proportion of costs are fixed, and were pounds sterling 257, pound sterling 216 and pound sterling 242 for DHPLC, SSCP and HA, respectively, assuming a throughput of 252 samples per year, or pound sterling 354, pound sterling 233 and pound sterling 259, assuming a throughput of 126 samples per year. DHPLC had the advantages of increased sensitivity and reduced labour costs when compared with more traditional approaches to exon screening but, unless expensive DHPLC equipment is being efficiently utilised for a very high proportion of the time available, overall costs are slightly higher.

Non-penetrance in tuberous sclerosis

As a result of extreme clinical variability in tuberous sclerosis, with one well-documented example of non-penetrance, phenotypically normal siblings or children of patients with tuberous sclerosis are thought to be at increased risk of having children with the disease. We report that the case of apparent non-penetrance that was previously described is the result of two independent tuberous-sclerosis mutations in the same family.

Parasite control methods used by horse owners: factors predisposing to the development of anthelmintic resistance in nematodes

One hundred and fifty horse owners, primarily private owners and riding schools, replied to a questionnaire concerning the practices they used to control parasites. Twenty-seven had experienced a parasite problem. Faecal samples from 188 horses selected at random showed that worm control practices were generally successful; however, many owners were not following recommendations for slowing the development of resistant parasites. In 1996, 86 per cent of the owners were using either three or two classes of anthelmintic a year, and they used a median of six doses with a range from one to 11. Approximately half the owners, more commonly owners of up to five horses, picked up their horses' faeces at least once a week, but these owners also used more doses of anthelmintic a year than owners who did not pick up faeces. One-third of the owners manually removed Gasterophilus species eggs from the horses' hairs, but 94 per cent of them also used ivermectin. Many owners treated specifically for Anoplocephala species, cyathostome larvae and Gasterophilus species, and these owners were the most likely to use three classes of anthelmintic a year. One-hundred-and-seven owners replied to a second questionnaire asking for information about the factors that influenced their anthelmintic control practices. Many owners, particularly private owners, were not influenced by the cost of the anthelmintic. For the timing and frequency of treatment, and the choice of drug, owners were most influenced by advertisements, magazine articles and veterinary surgeons. In two magazines aimed at horse owners, the brands of drugs most frequently advertised were the brands most commonly used by the owners, and articles in the magazines recommended the use of three classes of drug per year. These results are discussed in relation to their influence on the development of anthelmintic-resistant nematodes.

Necrotizing ulcerative stomatitis in human immunodeficiency virus-seropositive individuals: a review of the histopathologic, immunohistochemical, and virologic characteristics of 18 cases

OBJECTIVE

The purpose of this retrospective study was to delineate the histopathologic, immunohistochemical, and virologic characteristics of 18 cases of necrotizing ulcerative stomatitis.

STUDY DESIGN

Eighteen examples or oral ulcerations in human immunodeficiency virus-seropositive individuals were identified that displayed unique histopathologic features. Immunohistochemic staining for CD1a, CD3, CD23, CD68, HLA-DR, p24, cytomegalovirus, HSV-1, and HSV-2 was performed, along with in situ hybridization for Epstein-Barr virus RNA and special staining for bacteria and fungi.

RESULTS

The lesions demonstrated ulceration, extensive necrosis, leukocytoclasia, histiocytic vasculitis with luminal fibrin clots, and a prominent infiltrate of large atypical cells with amphophilic cytoplasm, vesicular nuclei, and prominent nucleoli, interspersed with crescentic histiocytes, a histologic picture resembling extranodal Kikuchi's disease. Immunohistochemical findings suggested that the large atypical cells were histiocytes. Fifty-six percent (10/18) of the cases were immunoreactive for human immunodeficiency virus p24 within focal histiocytes, whereas Epstein-Barr virus RNA was identified in 1 (6%) of 17 cases.

CONCLUSIONS

Necrotizing ulcerative stomatitis is an inflammatory disease characterized by specific, reproducible microscopic features. We postulate that the histopathologic resemblance of necrotizing ulcerative stomatitis to extranodal Kikuchi's disease reflects a similar immune response to differing pathogens.

Prenatal origins of allergic disease

The prevalence of asthma and related allergic disorders has increased considerably over the last 25 years. Because genetic stock has not changed, environmental factors must have influenced the phenotype. Infants who experience the development of allergy already have an altered immune response at birth. We have investigated the development of immune responses during gestation and the effect of maternal allergen exposure during pregnancy and infant exposure in the first month of life on the development of allergy and disease. There was higher specific peripheral blood mononuclear cell proliferation to house dust mite and birch pollen in the third trimester compared with the second trimester, with the first positive responses seen at 22 weeks gestation. Maternal exposure to birch pollen after 22 weeks resulted in higher infant peripheral blood mononuclear cell responses to birch pollen at birth. Infants born at term, with at least 1 atopic parent with asthma, who experienced the development of allergic symptoms and positive skin prick test by 1 year of age had raised proliferative responses to house dust mite at birth compared with those infants with no symptoms. In genetically predisposed individuals, antenatal factors including maternal and thereby fetal exposure to allergens and materno-placental-fetal immunologic interactions are active in determining whether an allergic predisposition is manifested as disease.

Preoperative radiotherapy for rectal cancer: implications for surgeons, pathologists and radiologists

BACKGROUND

Over 10,000 new cases of rectal cancer are reported in the UK each year and adjuvant treatments, such as preoperative radiotherapy, are now being used almost routinely.

METHODS

A literature review was performed on the Medline database for English language publications on preoperative radiotherapy and rectal cancer. The radioresponsiveness of rectal cancer, tumour downstaging, radiological staging of irradiated rectal cancer, effects of radiotherapy on anastomotic integrity, anorectal and genitourinary function, the role of preoperative radiotherapy in local excision of rectal cancer, and the histological changes peculiar to radiotherapy were evaluated.

RESULTS AND CONCLUSION

Following preoperative radiotherapy, rectal cancer may be downstaged or, occasionally, eradicated histologically. Rectal cancer can now be staged accurately before operation, but this is significantly less reliable following irradiation. The pathological specimen must be examined thoroughly before a tumour can be reported to have been eradicated, especially as unique histological changes are produced by radiotherapy. There is no evidence to suggest that preoperative radiotherapy adversely affects anastomotic integrity. It appears that preoperative radiotherapy has some adverse affects on long-term anorectal dysfunction, but this must not distract from its main objectives in rectal cancer, namely reduced local recurrence rates and improved overall survival.

Optimal temperature selection for mutation detection by denaturing HPLC and comparison to single-stranded conformation polymorphism and heteroduplex analysis

BACKGROUND

Denaturing HPLC (DHPLC) is a semi-automated method for detecting unknown DNA sequence variants. The sensitivity of the method is dependent on the temperature at which the analysis is undertaken, the selection of which is dependent on operator experience. To circumvent this, software has been developed for predicting the optimal temperature for DHPLC analysis. We examined the utility of this software.

METHODS

To maximize the relevance of our data for other investigators, we have screened 42 different amplimers from CFTR, TSC1, and TSC2. The samples consisted of 103 unique sequence heterozygotes and 126 wild-type homozygous controls.

RESULTS

At the temperature recommended by the software, 96% (99 of 103) of heterozygotes and all of the wild-type controls were correctly classified. This compares favorably with sensitivities of 85% for single-stranded conformation polymorphism and 82% for gel-based heteroduplex analyses of the same fragments.

CONCLUSIONS

Software-optimized DHPLC is a highly sensitive method for mutation detection. However, where sensitivity >96% is required, our data suggest that in addition to the recommended temperature, fragments should also be run at the recommended temperature plus 2 degrees C.

Conserved C-terminal region of global repressor KorA of broad-host-range plasmid RK2 is required for co-operativity between KorA and a second RK2 global regulator, KorB

KorA and KorB proteins of IncP1 plasmid RK2 are encoded in the central control region (ccr) of the plasmid and act as global regulators of plasmid genes for replication, transfer and stable inheritance. KorA represses seven promoters on RK2, by binding to a defined operator site, OA, which always occurs in promoter regions. KorB recognises another operator, OB, which is found 12 times on the RK2 genome, but not always in promoter regions. At five of the KorA-regulated promoters, an OBsequence is also present. The presence of both KorA and KorB leads to severely decreased promoter activity. By measuring repression at different levels of KorA and KorB alone and in combination, we showed that there is at least 3. 4-fold co-operativity between them at korApin vivo. Testing the ability of previously isolated KorA mutants to act in a co-operative way in the presence of KorB in vivo or in vitro showed that the C-terminal part of KorA between amino acid positions 68 and 83 is required for this co-operativity. This region is part of a segment that is highly conserved between KorA and two other RK2 proteins, TrbA and KlcB. We propose that this conserved region may provide the basis for co-operativity with KorB either indirectly, by modulating DNA structure near the KorB binding site, or directly by serving as the "recognition" patch of each protein by KorB. It may thus serve as a key domain in allowing a sensitive response of the global circuits to changes in repressor concentration and thus modulation of replication, transfer and maintenance.