Identification of a mutation that perturbs NF1 agene splicing using genomic DNA samples and a minigene assay.
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Alternative Splicing↗
Biomedical subjects
J Whittaker
Publications and source records attributed to J Whittaker.
Survival of male patients with incontinentia pigmenti carrying a lethal mutation can be explained by somatic mosaicism or Klinefelter syndrome.
Incontinentia pigmenti (IP), or "Bloch-Sulzberger syndrome," is an X-linked dominant disorder characterized by abnormalities of skin, teeth, hair, and eyes; skewed X-inactivation; and recurrent miscarriages of male fetuses. IP results from mutations in the gene for NF-kappaB essential modulator (NEMO), with deletion of exons 4-10 of NEMO accounting for >80% of new mutations. Male fetuses inheriting this mutation and other "null" mutations of NEMO usually die in utero. Less deleterious mutations can result in survival of males subjects, but with ectodermal dysplasia and immunodeficiency. Male patients with skin, dental, and ocular abnormalities typical of those seen in female patients with IP (without immunodeficiency) are rare. We investigated four male patients with clinical hallmarks of IP. All four were found to carry the deletion normally associated with male lethality in utero. Survival in one patient is explained by a 47,XXY karyotype and skewed X inactivation. Three other patients possess a normal 46,XY karyotype. We demonstrate that these patients have both wild-type and deleted copies of the NEMO gene and are therefore mosaic for the common mutation. Therefore, the repeat-mediated rearrangement leading to the common deletion does not require meiotic division. Hypomorphic alleles, a 47,XXY karyotype, and somatic mosaicism therefore represent three mechanisms for survival of males carrying a NEMO mutation.
Alleles↗
Alanine scanning mutagenesis of a type 1 insulin-like growth factor receptor ligand binding site.
The high resolution crystal structure of an N-terminal fragment of the IGF-I receptor, has been reported. While this fragment is itself devoid of ligand binding activity, mutational analysis has indicated that its N terminus (L1, amino acids 1-150) and the C terminus of its cysteine-rich domain (amino acids 190-300) contain ligand binding determinants. Mutational analysis also suggests that amino acids 692-702 from the C terminus of the alpha subunit are critical for ligand binding. A fusion protein, formed from these fragments, binds IGF-I with an affinity similar to that of the whole extracellular domain, suggesting that these are the minimal structural elements of the IGF-I binding site. To further characterize the binding site, we have performed structure directed and alanine-scanning mutagenesis of L1, the cysteine-rich domain and amino acids 692-702. Alanine mutants of residues in these regions were transiently expressed as secreted recombinant receptors and their affinity was determined. In L1 alanine mutants of Asp(8), Asn(11), Tyr(28), His(30), Leu(33), Leu(56), Phe(58), Arg(59), and Trp(79) produced a 2- to 10-fold decrease in affinity and alanine mutation of Phe(90) resulted in a 23-fold decrease in affinity. In the cysteine-rich domain, mutation of Arg(240), Phe(241), Glu(242), and Phe(251) produced a 2- to 10-fold decrease in affinity. In the region between amino acids 692 and 702, alanine mutation of Phe(701) produced a receptor devoid of binding activity and alanine mutations of Phe(693), Glu(693), Asn(694), Leu(696), His(697), Asn(698), and Ile(700) exhibited decreases in affinity ranging from 10- to 30-fold. With the exception of Trp(79), the disruptive mutants in L1 form a discrete epitope on the surface of the receptor. Those in the cysteine-rich domain essential for intact affinity also form a discrete epitope together with Trp(79).
Alanine↗
Psychiatric symptoms and CAG repeats in neurologically asymptomatic Huntington's disease gene carriers.
The putative relationship between the psychiatric profile of a sample of neurologically asymptomatic Huntington's disease gene carriers and CAG repeats was investigated. The psychiatric assessments (by consultant psychiatrist and computerised battery) were undertaken before the genetic testing was carried out. In this way, the informational distortions caused by neurological and cognitive deficits were avoided. The hypothesis that there is a relationship between psychiatric and CAG repeats was tested by seeking direct correlations between psychiatric systems and CAG repeats, and also by correcting the correlation by the number of years above or below the estimated age of onset in Huntington's disease. Scores for irritability and cognitive failures were high in the sample. There was no correlation between any psychiatric variable and CAG repeats. Possible explanations for this lack of correlations are discussed.
Adenine↗
Trauma systems--state of the art.
Trauma is an inevitable consequence of the lives we lead. There are many approaches to dealing with it but an ideal system, universally applicable, probably does not exist because of the national variations in social, economic, cultural and geographical characteristics. Many countries are beginning to recognise that the 'systems' they have in place for dealing with the burden of trauma are seriously deficient and that this situation cannot be allowed to continue into the new millennium. However, it is highly unlikely that in the near future. governments will suddenly find substantial extra finance for trauma care or the implementation of new systems. Throughout many countries, the individual components of trauma care systems are in place but, for whatever reasons, there is a lack of integration, which results in suboptimal care. The system we all should be aiming for is one of closer communication and greater cooperation. By taking into account community and national needs, available resources, and adapting what is currently in place it should then be possible to create 'a set of things working together as parts of a trauma mechanism'.
Emergency Medical Services↗
Randomised phase II trial of pegylated liposomal doxorubicin (DOXIL/CAELYX) versus doxorubicin in the treatment of advanced or metastatic soft tissue sarcoma: a study by the EORTC Soft Tissue and Bone Sarcoma Group.
CAELYX/DOXIL, pegylated liposomal doxorubicin, has shown antitumour activity and reduced toxicity compared with standard doxorubicin in other tumour types. In this prospective randomised trial, 94 eligible patients with advanced soft-tissue sarcoma (STS) were treated, 50 with CAELYX (50 mg/m(2) by a 1 h intravenous (i.v.) infusion every 4 weeks) and 44 with doxorubicin (75 mg/m(2) by an i.v. bolus every 3 weeks). Histological subtypes were evenly matched, 33% were leiomyosarcoma (CAELYX: 18; doxorubicin: 13). Primary disease sites were well matched. CAELYX was significantly less myelosuppressive, only 3 (6%) patients had grade 3 and 4 neutropenia, versus 33 (77%) on doxorubicin; febrile neutropenia occurred in 7 (16%) patients given doxorubicin, but only 1 (2%) given CAELYX. 37 (86%) patients on doxorubicin had grade 2-3 alopecia, but only 3 (6%) on CAELYX, and the major toxicity with CAELYX was to the skin. Palmar-plantar erythrodysesthesia with CAELYX was grade 1: 4 (8%) patients, grade 2: 11 (22%) patients, grade 3: 9 (18%) patients and grade 4: 1 (2%) patient. Other non-haematological grade 3 and 4 toxicities were rare. Confirmed responses were observed with both agents: CAELYX: complete response (CR) 1 (uterine), partial response (PR) 4 (response rate (RR) 10%); and doxorubicin: CR 1, PR 3 (RR of 9%); with the best response being stable disease (NC) in 16 and 18 patients, respectively. The reason for the low response rate is unknown, but it may be due partly to a high proportion of gastrointestinal stromal tumours. In conclusion, CAELYX has equivalent activity to doxorubicin in STS with an improved toxicity profile and should be considered for further investigation in combination with other agents such as ifosfamide.
Adult↗
Phase II study of pegylated liposomal doxorubicin (Caelyx) as induction chemotherapy for patients with squamous cell cancer of the head and neck.
A phase II trial of pegylated liposomal doxorubicin (Caelyx) as induction chemotherapy was conducted in 20 patients with treatment-naïve squamous cell cancer of the head and neck (SCCHN). 10 patients received two cycles of Caelyx (40 mg/m(2)) every 3 weeks before starting radical radiotherapy (RT). Subsequently, consecutive groups of 3 patients received a third escalating dose of Caelyx (10, 15 and 20 mg/m(2)) 3 days before RT. 9 of 18 (50%, 95% confidence intervals (CI): 26-74%) evaluable patients responded to Caelyx, with 11 responses in 26 (42%, 95% CI: 24-62%) evaluable sites (three complete responses (12%), eight partial responses (31%)). There was no grade 3/4 haematological, mucosal or cardiac toxicity. Nausea and vomiting were minimal. There were no drug-related RT delays. Local RT-induced toxicity was not increased. Caelyx has significant activity against SCCHN and warrants further investigation in this disease. In view of its tumour targeting properties and activity at moderate doses, it may be useful in concomitant chemoradiotherapy strategies for SCCHN.
Aged↗
Phase I-II study of pegylated liposomal cisplatin (SPI-077) in patients with inoperable head and neck cancer.
BACKGROUND: Concomitant chemoradiotherapy (CCRT) for squamous cancers of the head and neck (SCCHN) improves survival but increases toxicity. Pegylated liposomes localise to solid cancers and may deliver radiosensitizing agents preferentially to tumour tissue, potentially improving the therapeutic ratio of CCRT. PATIENTS AND METHODS: A phase I-II trial of pegylated liposome encapsulated cisplatin (SPI-077) was conducted in 18 patients with treatment-naive locally advanced, inoperable SCCHN. The first 10 patients received 2 cycles of 200 mg/m2, and the next 8 received 260 mg/m2, every 3 weeks before commencing radical radiotherapy (RT). RESULTS: Only 2 of 18 (11%) patients had partial responses to SPI-077 with 2 responses in 29 (6.9%) evaluable sites. SPI-077 was tolerated well with no haematological, renal, hepatic or neurological toxicities. Nausea and vomiting were minimal. There were no drug-related delays in the delivery of RT. RT-induced mucosal and cutaneous toxicity were not significantly increased. CONCLUSIONS: SPI-077 is essentially inactive against SCCHN and, in its present formulation, does not merit further evaluation as induction chemotherapy or as part of a CCRT approach.
Aged↗
Trypanosoma brucei infection induces apoptosis and up-regulates neuroleukin expression in the cerebellum.
Human infection with Trypanosoma brucei may result in meningo-encephalitis, neuronal demyelination, blood-brain-barrier dysfunction, peri-vascular infiltration, astrocytosis and neuronal apoptosis. Prevention of the short- or long-term, parasite-induced, neuronal assault requires a better understanding of the host's responses to the infection at the molecular level. Northern analysis, cDNA micro-arrays, reverse-transcriptase-PCR (RT-PCR), SDS-PAGE and immunohistology were therefore used to investigate global gene and protein expression in the brains of mice infected with T. brucei. Temporal and spatial expression of neuroleukin (NLK), a predominant neurotrophin which is associated with neuronal protection and regeneration during neuronal assault in the brain, was then assessed. Expression of 20 of the 588 genes investigated (representing pro- and anti-inflammatory immuno-modulators, growth factors, neurotransmitters, and pro- and anti-apoptosis factors) was significantly altered (P < 0.05). TUNEL analysis revealed extensive apoptosis at peak parasitaemia, mainly in the cerebellum. RT-PCR analysis of two regulators of apoptosis, Bcl-x(L) (anti-apoptotic) and Bax (pro-apoptotic), revealed equivalent increases in levels of expression. NLK expression was up-regulated in punctated fashion in brain and was mainly localized to abnormal (stellate) catecholamine neurons (CN) in the locus coeruleus (LC) of infected [and, to a lesser degree, the normal (polygonal) cells of uninfected] brainstem. Expression of NLK receptor (NLK-R) was inversely correlated with that of NLK. At peak parasitaemia, trypanosome infection apparently induces cerebellar apoptosis and a corresponding increase in NLK expression. NLK may be modulating inflammation and is probably involved in protecting CN and the cerebellum against apoptosis.
Animals↗
Comparative sequence analysis (CSA): a new sequence-based method for the identification and characterization of mutations in DNA.
Direct sequencing analysis is largely used to confirm and characterize mutations previously detected by more rapid tests. We have developed a method-Comparative Sequence Analysis (CSA)-that simplifies the analysis of sequencing data facilitating its use as a first screen for mutation detection. Sequence data were split into their component electrophoretograms and the use of a size standard enabled equivalent traces from different individuals to be overlaid. This allowed simple and rapid visual analysis of the results. Using this technique in a blind study, we tested 576 samples for mutations in the Von Hippel-Lindau tumor suppressor gene, VHL. We were able to identify and characterize all 78 known mutations present within the sample set (100% sensitivity and specificity).
DNA Mutational Analysis↗
Gastroenteropancreatic hormones (insulin, glucagon, somatostatin, and multiple forms of PYY) from the pallid sturgeon, Scaphirhynchus albus (Acipenseriformes).
Insulin, glucagon, somatostatin-14, and three structurally related molecular forms of peptide tyrosine-tyrosine (PYY) were isolated from an extract of the combined pancreas and gastrointestinal tract of the pallid sturgeon, Scaphirhynchus albus. Pallid sturgeon insulin was identical to insulin from the Russian sturgeon, Acipenser guldenstaedti, and to insulin-2 from the paddlefish, Polyodon spathula, and was approximately twofold less potent than human insulin in inhibiting the binding of [3-[(125)I] iodotyrosine-A14] human insulin to the soluble human insulin receptor. The sturgeon glucagon (HSQGMFTNDY(10)-SKYLEEKLAQ(20) EFVEWLKNGK(30)S), like the two paddlefish glucagons, contains 31 rather than 29 amino acid residues, indicative of an anomalous pathway of posttranslational processing of proglucagon. Pallid sturgeon somatostatin, identical to human somatostatin-14, was also isolated in a second molecular form containing an oxidized tryptophan residue, but [Pro(2)]somatostatin-14, previously isolated from the pituitary of A. guldenstaedti, was not identified. Sturgeon PYY (FPPKPEHPGD(10)DAPAEDVAKY(20)YTALRHYINL(30) ITRQRY.HN(2)) was also isolated in variant forms containing the substitutions (Phe(1) --> Ala) and (Ala(18) --> Val), indicative of at least two gene duplications occurring within the Acipenseriformes lineage. The amino acid sequences of the pallidsturgeon PYY peptides are appreciably different from the proposed "ancestral" PYY sequence that has otherwise been very strongly conserved among the actinopterygian and elasmobranch fish.
Amino Acid Sequence↗
Discharge from intensive care: a view from the ward.
Relocation stress is a common phenomenon in patients discharged from an intensive care unit (ICU) to a ward. A variety of nursing interventions, initiated by intensive care nurses, have been introduced following research in this area. Ward nurses are ideally situated to minimize stress in this patient population, yet their contribution has not been considered. The aim of this study was to identify the experience of the ward nursing staff when receiving a patient from the ICU. An exploratory pilot study was conducted over a 6-month period. The sample group comprised nursing staff in two wards, who regularly received ICU patients. Data collection methods were triangulated and involved the use of open-ended questionnaires and semi-structured interviews. Thirty-six questionnaires were sent, yielding a 36.1% (n = 13) response rate. Seven staff of various grades were interviewed. Data analysis was undertaken using Burnard's (1991) Thematic Content Analysis. Four major categories were identified in the analysis of the data. These were emotions; problems; communication; and interventions. However, the experience of ward staff receiving patients from intensive care differed according to grade.
Adaptation, Psychological↗
Cryptic von Hippel-Lindau disease: germline mutations in patients with haemangioblastoma only.
OBJECTIVES: Central nervous system haemangioblastoma (HAB) is a major feature of von Hippel-Lindau (VHL) disease, and it is estimated that about 30% of HAB patients have VHL disease. Consequently, it is widely recommended that sporadic HAB patients are screened for clinical and radiological features of VHL disease because of the risk of multiple tumours. We investigated the frequency of VHL germline mutations in patients with HAB only with no clinical or radiological evidence of VHL disease to define the role of molecular genetic analysis in the management of such patients. METHODS: Eighty four patients with a single HAB (23 Dutch, 61 UK) and four with multiple HAB (two Dutch, two UK) were studied by direct sequencing of the coding region and quantitative Southern blotting. RESULTS: A VHL germline mutation was found in three of 69 (4.3%) single HAB patients aged 50 years or less (three of 84 (3.6%) total single HAB patients). A germline VHL mutation was detected in a 44 year old woman with a solitary cerebellar HAB, as well as in four clinically unaffected close relatives, and in two single HAB cases presenting at the ages of 29 and 36 years. Germline VHL mutations were detected in two of four cases with multiple HAB. CONCLUSIONS: Early detection of VHL disease is important to reduce morbidity and mortality and therefore we recommend that, in addition to conventional clinical and radiological investigations, VHL gene mutation analysis should be offered to all HAB patients younger than 50 years. HAB patients aged >50 years will have a lower a priori risk of VHL disease and further data are required to evaluate the role of routine molecular genetic investigations in late onset HAB cases. The failure to detect germline VHL mutations in some patients with multiple HAB may indicate the presence of somatic mosaicism or additional HAB susceptibility genes.
Adolescent↗
Generalization of the extended transmission disequilibrium test to two unlinked disease loci.
The extended transmission disequilibrium test (ETDT) of Sham and Curtis [1995] is a powerful test of the null hypothesis of no linkage between a multi-allelic marker locus and a disease susceptibility locus of unknown location in the presence of association between alleles at the two loci. We propose a generalization of the ETDT to test simultaneously for linkage of markers to two unlinked disease loci. Analysis of the simulated data for Problem 2 would suggest improvements in power to detect linkage to pairs of disease loci over single locus tests. This is as a result of the two locus model taking account of epistasis between the disease loci.
Alleles↗
Haemostatic and fibrinolytic responses to bone marrow transplantation.
Thrombin and plasmin activation markers were serially measured in 80 patients undergoing bone marrow transplantation (BMT). There were prothrombotic and fibrinolytic responses observed during autograft and allograft BMTs. Thrombin-antithrombin and prothrombin fragment F1+2 levels increased from day -7 to -3 (P<0.0001) from 3.7 to 7 ng/ml and 1.2 to 1.63 nmol/l, respectively. A rise in plasmin-antiplasmin levels occurred between days 4 and 14 (P< 0.0004), from 393 ng/ml on day -7 to a peak of 795 ng/ml on day 11. No correlation between reduced protein C levels post-BMT and a prothrombotic state was observed.
Adolescent↗
The interaction of DNA-targeted platinum phenanthridinium complexes with DNA.
Cisplatin analogues were synthesised that consisted of platinum(II) diamine complexes tethered via a polymethylene chain ( n = 3, 5, 8 and 10) to a phenanthridinium cation. Both chloro and iodo leaving groups were examined. DNA adduct formation was quantitatively analysed using a linear amplification system with the plasmid pGEM-3Zf(+). This system utilised Taq DNA polymerase to extend from an oligonucleotide primer to the damage site. This damage site inhibited the extension of the DNA polymerase. The products were electrophoresed on a DNA sequencing gel enabling adduct formation to be determined at base pair resolution. The damage intensity at each site was determined by densitometry. The platinum phenanthridinium complexes were shown to damage DNA at shorter incubation times than cisplatin. To produce similar levels of damage, an 18 h incubation was required for cisplatin compared to 30 min for the n = 3 platinum phenanthridinium complexes; this indicates that the intercalating chromophore causes a large increase in the rate of platination. A reaction mechanism involving direct displacement of the chloride by the N-7 of guanine may account for the rate increase. These results indicate that further development of these compounds could lead to more effective cancer chemotherapeutic agents.
Antineoplastic Agents↗
Systematic review of efficacy of cognitive behaviour therapies in childhood and adolescent depressive disorder.
OBJECTIVE: To determine whether cognitive behaviour therapy is an effective treatment for childhood and adolescent depressive disorder. DESIGN: Systematic review of six randomised trials comparing the efficacy of cognitive behaviour therapy with inactive interventions in subjects aged 8 to 19 years with depressive disorder. MAIN OUTCOME MEASURE: Remission from depressive disorder. RESULTS: The rate of remission from depressive disorder was higher in the therapy group (129/208; 62%) than in the comparison group (61/168; 36%). The pooled odds ratio was 3.2 (95% confidence interval 1.9 to 5.2), suggesting a significant benefit of active treatment. Most studies, however, were based on relatively mild cases of depression and were of only moderate quality. CONCLUSIONS: Cognitive behaviour therapy may be of benefit for depressive disorder of moderate severity in children and adolescents. It cannot, however, yet be recommended for severe depression. Definitive large trials will be required to determine whether the results of this systematic review are reliable.
Adolescent↗
DNA sequence selectivity of cisplatin analogues in intact human cells.
The sequence specificity of ten cisplatin analogues was examined in intact human cells. Six of these compounds have anti-tumour activity. The sequence selectivity was investigated using a Taq DNA polymerase/linear amplification assay on damaged DNA extracted from treated cells. Cisplatin and tetraplatin(IV) produced strong damage and DACH RR(II) and cis-[Pt(II)Cl,2(iPrNH2)2] weak DNA damage in intact HeLa cells. The sequence selectivity of tetraplatin(IV) in intact human cells was very similar to that of cisplatin and favored runs of consecutive purines, especially consecutive guanines. The compounds transplatin, carboplatin, cis-[PtCl(NH3)2(C8H17.NH2)], cis-[PtCl2(iPentNH2)2], cis-[PtCl2(C6H11NH2)2, DACH SS(II) and CHIP(IV) did not significantly damage DNA in cells. It was concluded that the interactions of these cisplatin analogues with DNA in human cells were strongly influenced by their ability to damage purified DNA.
Antineoplastic Agents↗