Search PubMed⌕ Search

Biomedical subjects

M Cullen

Publications and source records attributed to M Cullen.

At least 37 records · Page 2Linked to original sources
PubMed1998

Intensive induction-sequential chemotherapy with BOP/VIP-B compared with treatment with BEP/EP for poor-prognosis metastatic nonseminomatous germ cell tumor: a Randomized Medical Research Council/European Organization for Research and Treatment of Cancer study.

PURPOSE: The aim of this randomized trial was to assess the potential therapeutic advantage of an intensive induction-sequential chemotherapy schedule (bleomycin, vincristine, cisplatin [BOP])/etoposide, ifosfamide, cisplatin, and bleomycin [VIP-B]), compared with a regimen based on bleomycin, etoposide, and cisplatin (BEP) (BEP/etoposide and cisplatin [EP]) for the treatment of patients with poor-prognosis metastatic nonseminomatous germ cell tumors (NSGCTs). PATIENTS AND METHODS: Patients had one or more of the following: a retroperitoneal mass > or = 10 cm in diameter; mediastinal or supraclavicular mass > or = 5 cm in diameter; at least 20 lung metastases (any size); liver, bone, or brain metastases; and serum beta human chorionic gonadotropin (betaHCG) > or = 10,000 IU/L or alfa fetoprotein (AFP) > or = 1,000 IU/L. A total of 380 patients were accrued between May 1990 and June 1994 into this joint Medical Research Council (MRC)/European Organization for Research and Treatment of Cancer (EORTC) trial; of these, nine patients were deemed ineligible. RESULTS: There was no significant difference between the two arms in the proportion of patients who achieved a complete response (CR) with chemotherapy alone, ie, 79 of 185 assessable patients (57%) with BEP/EP and 72 of 186 (54%) with BOP/VIP-B (P = 0.687). With a median follow-up of 3.1 years (maximum, 5.8), a total of 107 patients (28%) had progressive disease. There was no significant difference in time to first disease progression, or failure-free or overall survival between the two arms (P = 0.21, 0.101, and 0.190, respectively). The 1-year failure-free survival rates for BEP/EP and BOP/VIP-B were 60% (95% confidence interval [CI], 53% to 67%) and 53% (95% CI, 47% to 61%). Grade 3 or 4 myelosuppression, febrile neutropenia, and weight loss were more pronounced with BOP/VIP-B than with BEP/EP, and there were more toxic deaths with BOP/VIP-B than BEP/EP (18 [9%] v nine [5%]). CONCLUSION: The intensive BOP/VIP-B therapy was associated with more toxicity, but there was no evidence of an improvement in response rate or survival compared with treatment with BEP/EP.

Adolescent↗
PubMed1998

Filgrastim during combination chemotherapy of patients with poor-prognosis metastatic germ cell malignancy. European Organization for Research and Treatment of Cancer, Genito-Urinary Group, and the Medical Research Council Testicular Cancer Working Party, Cambridge, United Kingdom.

PURPOSE: To determine the effect of r-metHu granulocyte colony-stimulating factor (G-CSF) on the proportion of patients with metastatic poor-prognosis malignant germ cell tumors who receive full dose-intensity combination chemotherapy. PATIENTS AND METHODS: In a phase III study patients received six cycles of BEP/EP (etoposide, and cisplatin, plus or minus bleomycin) or six cycles of BOP/VIP-B (bleomycin, vincristine, cisplatin/etoposide, ifosfamide, cisplatin, bleomycin). A subset were secondarily randomized to receive or not receive filgrastim. Filgrastim 5 microg/kg/day was administered subcutaneously on days 3 through 9 after each BOP and on days 6 through 19 after each VIP, BEP, or EP cycle. RESULTS: Eighty-five percent of 120 eligible patients randomized to filgrastim received at least six chemotherapy cycles compared with 70% of 130 patients randomized to not receive filgrastim (VCP = .003). Patients in the filgrastim-arm achieved significantly higher dose-intensities. Neutropenic fever occurred in 25 of 128 filgrastim-patients and in 38 of 129 non-filgrastim-patients (P = .052). Twelve and three toxic deaths occurred in the non-filgrastim- and filgrastim-arms, respectively. Nine of the 12 toxic deaths and all of the three toxic deaths were associated with febrile grade 4 neutropenia. Failure-free and overall survival were similar in both arms. CONCLUSION: During combination chemotherapy in patients with malignant germ cell tumors, the routine use of filgrastim significantly improved the delivery of the planned treatment schedule without effect on failure-free or overall survival. The use of filgrastim was associated with a clinically important reduction in the number of toxic deaths, confined to the experimental intensified-chemotherapy schedule. This study does not support the routine use of filgrastim during standard chemotherapy with BEP.

Adolescent↗
PubMed1997

Chromosomal localization of three human dual specificity phosphatase genes (DUSP4, DUSP6, and DUSP7).

Mitogen-activated protein (MAP) kinase phosphatases constitute a growing family of dual specificity phosphatases thought to play a role in the dephosphorylation and inactivation of MAP kinases and are therefore likely to be important in the regulation of diverse cellular processes such as proliferation, differentiation, and apoptosis. For this reason it has been suggested that MAP kinase phosphatases may be tumor suppressors. We have determined the chromosomal locations of three human dual specificity phosphatase genes by fluorescence in situ hybridization and radiation hybrid mapping. The genes were localized to three different chromosomes, MKP2 (DUSP4) to 8p11-p12, MKP3 (DUSP6) to 12q22-q23, and MKPX (DUSP7) to 3p21. This will allow the potential roles of these genes in disease processes to be evaluated.

Base Sequence↗
PubMed1997

The protective effect of beta-carotene and retinol on ventilatory function in an asbestos-exposed cohort.

The association between serum beta-carotene or retinol concentration and level of ventilatory function was investigated in a population of asbestos-exposed men with a high rate of current and former cigarette smoking. The study population consisted of 816 subjects enrolled in the pilot component of the Carotene and Retinol Efficacy Trial (CARET), a placebo-controlled trial of supplemental beta-carotene and retinyl palmitate for the chemoprevention of lung cancer. Data available for analysis included baseline questionnaire, spirometry, chest X-ray, food frequency questionnaire, and serum beta-carotene and retinol concentrations. Serum beta-carotene concentration was associated with FEV1 (p < 0.05) and FVC (p < 0.05), with an approximately 100-ml increase over predicted values associated with raising the serum concentration from the 25th to the 75th percentile of the distribution in the study population (absolute difference = 155 ng/ml), even after adjustment for the confounding effects of asbestos exposure and cigarette smoking. Raising the serum retinol concentration from the 25th to the 75th percentile (absolute difference = 211 ng/ml) was associated with an approximately 70 ml increase in FVC (p < 0.05) over the predicted value. These results provide support for the hypothesis that beta-carotene and retinol have a protective effect on loss of ventilatory function.

Aged↗
PubMed1997

Characterization of recombination in the HLA class II region.

Studies of linkage disequilibrium across the HLA class II region have been useful in predicting where recombination is most likely to occur. The strong associations between genes within the 85-kb region from DQB1 to DRB1 are consistent with low frequency of recombination in this segment of DNA. Conversely, a lack of association between alleles of TAP1 and TAP2 (approximately 15 kb) has been observed, suggesting that recombination occurs here with relatively high frequency. Much of the HLA class II region has now been sequenced, providing the tools to undertake detailed analysis of recombination. Twenty-seven families containing one or two recombinant chromosomes within the 500-kb interval between the DPB1 and DRB1 genes were used to determine patterns of recombination across this region. SSCP analysis and microsatellite typing yielded identification of 127 novel polymorphic markers distributed throughout the class II region, allowing refinement of the site of crossover in 30 class II recombinant chromosomes. The three regions where recombination was observed most frequently are as follows: the 45-kb interval between HLA-DNA and RING3 (11 cases), the 50-kb interval between DQB3 and DQB1 (6 cases), and an 8.8-kb segment of the TAP2 gene (3 cases). Six of the 10 remaining recombinants await further characterization, pending identification of additional informative markers, while four recombinants were localized to other intervals (outliers). Analysis of association between markers flanking HLA-DNA to RING3 (45 kb), as well as TAP1 to TAP2 (15 kb), by use of independent CEPH haplotypes indicated little or no linkage disequilibrium, supporting the familial recombination data. A notable sequence motif located within a region associated with increased rates of recombination consisted of a (TGGA)12 tandem repeat within the TAP2 gene.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Localization of the recombination points in a family with two DR/DP recombinations.

In a family with a maternal DR/GLO recombination, cellular DP typing showed it to be located between DR and DP. RFLP studies done during the 9th international histocompatibility workshop gave anomalous segregation patterns of DPA and DPB bands that could be interpreted as being due to a second, paternal DR/DP recombination. This assumption was confirmed later by PCR-SSO typing. A more precise mapping has been done by new markers showing the maternal recombination to be within the TAP2 locus and the paternal recombination to be between DQB1 and DQB3. This supports earlier suggestions of a hot spot of recombination in the TAP region. The recombinations involve parental haplotypes that presently show DR/DP linkage disequilibrium in the French population and it is proposed that DR/DP recombinations occur randomly while B/DR recombinations preferentially occur on haplotypes without strong linkage disequilibrium. Existing DR/DP linkage disequilibria in a given population will thus be broken down with time. The mixed lymphocyte culture response towards an isolated DP difference was tested in this and another DR/DP recombinant family. It showed that an alloresponse towards DP may be highly variable and this suggests that it might be important to define the rules for the strength of this reaction and the possible implications for allotransplantation.

Female↗
PubMed1995

Molecular mapping of a recombination hotspot located in the second intron of the human TAP2 locus.

Recombination across the HLA class II region is not randomly distributed, as indicated by both strong linkage disequilibrium within the 100 kb encompassing the DRB1-DQA1-DQB1 loci and complete equilibrium between TAP1 and TAP2, the closest variant sites of which are < 15 kb. In an attempt to explain these observations, 39 novel polymorphic markers in a region encompassing the TAP, LMP, and DOB genes were used to delineate the site of crossover in 11 class II recombinant chromosomes. SSCP demonstrated that two recombination events occurred within an 850-bp interval in the second intron of TAP2, which separates the variant sites of TAP1 and TAP2. These data indicate the presence of a recombination hotspot, the first to be identified from the analysis of familial transmission in the human major histocompatibility complex. The region of crossover was cloned and sequenced from one of the recombinants, further defining the crossover site to a 138-bp segment nested within the 850-bp region. This represents the most precisely defined region of recombination in the human genome.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Risk factors for Alzheimer's disease and dementia: a case-control study based on the MRC elderly hypertension trial.

We surveyed 1,545 subjects--recruited into the UK Medical Research Council elderly hypertension treatment trial between 1982 and 1987--to detect incident cases of dementia, identifying 50 cases of dementia, including 31 cases of probable or possible Alzheimer's disease (AD). These we compared with 223 unimpaired, unmatched controls from the same population for exposure to familial, cardiovascular, educational, and geographic risk factors for dementia. Our study confirms the association of family history of dementia with dementia (odds ratio [OR] = 4.36) and AD (OR = 4.69), and of advanced age with dementia (OR = 2.81). Rural residence exerted a protective effect for dementia (OR = 0.21) and AD (OR = 0.28). We report near-significant associations between AD and dementia and several cardiovascular risk factors (ECG ischemia, systolic hypertension, and smoking) among subjects lacking a family history of dementia. We postulate the existence of a nonfamilial form of dementia transcending traditional categories of multi-infarct dementia and AD, more common among urban residents, and mediated through vascular pathology. Risk factors reported elsewhere but not confirmed in this study were advanced maternal age and winter season of birth.

Aged↗
PubMed1993

Automated integration of external databases: a knowledge-based approach to enhancing rule-based expert systems.

Expert system applications in the biomedical domain have long been hampered by the difficulty inherent in maintaining and extending large knowledge bases. We have developed a knowledge-based method for automatically augmenting such knowledge bases. The method consists of automatically integrating data contained in commercially available, external, online databases with data contained in an expert system's knowledge base. We have built a prototype system, named DBX, using this technique to augment an expert system's knowledge base as a decision support aid and as a bibliographic retrieval tool. In this paper, we describe this prototype system in detail, illustrate its use, and discuss the lessons we have learned in its implementation.

Artificial Intelligence↗
PubMed1993

The 'SiteRite' ultrasound machine--an aid to internal jugular vein cannulation.

The 'SiteRite' is a portable ultrasound imaging system designed to aid vein location during internal jugular vein cannulation. It was compared to the use of anatomical landmarks for internal jugular vein cannulation. It was easy to use and gave good quality images, increased the speed of cannulation, decreased the number of attempts to locate the internal jugular vein and reduced the failure rate, although it had no effect on the incidence of carotid artery puncture.

Catheterization, Central Venous↗
PubMed1993

Potentiation of the hypoglycaemic response to glipizide in diabetic patients by histamine H2-receptor antagonists.

In a randomised placebo controlled study, two groups of six maturity onset diabetic patients stabilised on glipizide were given cimetidine (400 mg) or ranitidine (150 mg) 3 h before a standardised meal. In comparison with placebo, both cimetidine and ranitidine significantly reduced the post-prandial rise in blood glucose by a mean of 40% and 25% respectively producing glucose levels of less than 3 mmol l-1 (lowest 1.5 mmol l-1) in four patients. Both drugs also significantly increased plasma glipizide AUC by approximately 20%. Caution should be exercised when initiating treatment with H2-receptor antagonists in diabetics receiving sulphonylurea hypoglycaemic agents.

Aged↗