Familiarizing medical students with complementary and alternative medicine: encouraging new attitudes and ideas.
Explore the source record for details and available documents.
Attitude of Health Personnel↗
Biomedical subjects
D Owen
Publications and source records attributed to D Owen.
Bordetella pertussis surveillance in England and Wales: 1995-7.
Available data sources on disease due to Bordetella pertussis, including notifications, hospital admissions, deaths, and an enhanced laboratory-based surveillance system commenced in January 1994, were reviewed for the period 1995-7. Pertussis notifications continued their approximately 3-year cycle although at historically reduced levels. A slight seasonal increase in late summer/early autumn existed over and above a relatively constant background rate. Over time, the proportion of pertussis cases in younger, unvaccinated children, and to a lesser extent, adolescents and young adults, is increasing. There is a continuing significant and underreported mortality associated with pertussis in the very young age group. Disease due to serotype 1,2 is on the increase despite persistent high vaccination levels and this serotype causes more severe disease. The provision of preventative antibiotics prior to disease onset reduced the severity of the disease but its use remains uncommon in England and Wales. While overall levels of pertussis notifications have declined in recent times, vaccination efficacy wanes with increasing age, and pertussis remains a significant cause of mortality and severe morbidity in the very young. This could be reduced by timely booster vaccination and increased recognition of mild disease in older cases followed by early antibiotic therapy for the very young household contacts.
Adolescent↗
Delineation of the Cdc42/Rac-binding domain of p21-activated kinase.
p21-activated kinases (PAKs) serve as effector proteins for the GTP-binding proteins Cdc42 and Rac. They are serine/threonine kinases containing the Cdc42/Rac interactive binding (CRIB) motif. The main aim of this study was to define the minimal domain of alphaPAK required for Cdc42/Rac binding. Eight stable PAK fragments of varying lengths, each containing the CRIB motif (residues 75-88), were expressed in Escherichia coli, and their ability to interact with Cdc42 and Rac was assessed using scintillation proximity assays, isothermal titration calorimetry, and fluorescence techniques. The shortest fragments examined (residues 70-94 and 75-94) bound only weakly to either Cdc42 or Rac. A longer fragment starting at residue 75 and ending at residue 105 showed binding to Q61L Rac.GTP with Kd = 1.9 microM. Highest affinity binding (Kd approximately 0.05 microM) was seen with longer fragments ending at residue 118 or 132. A small increase in affinity was seen with those fragments starting at residue 70 rather than residue 75. PAK fragments bound with approximately 3-10-fold higher affinity to Cdc42 than to Rac and bound Q61L variants with 5-10-fold higher affinity than wild type. The dissociation rates of Q61L Rac.mant-GTP and of Q61L Cdc42. mant-GTP from PAK fragment residues 70-132 were measured to be 0.66 and 0.25 min-1, respectively, which are 100-fold lower than dissociation rates for Ras:Ras-effector domains, although their affinities are similar. Calorimetric measurements revealed that binding was associated with a relatively slow heat change. It is suggested that these PAK fragments (in the absence of Cdc42 or Rac) might exist predominantly in an inactive conformation that slowly interconverts with an active conformation and/or a slow conformational change may occur upon binding to Cdc42/Rac. In conclusion, the PAK CRIB motif itself is insufficient for high-affinity binding to Cdc42/Rac, but a 30 amino acid region of PAK (residues 75-105), containing this motif, is sufficient.
Amino Acid Sequence↗
Site-specific cross-linking of amino acids in the basic region of human immunodeficiency virus type 1 Tat peptide to chemically modified TAR RNA duplexes.
The Human Immunodeficiency Virus type 1 Tat protein interacts specifically with a U-rich bulge within an RNA stem-loop known as the trans-activation responsive region (TAR) that occurs in all viral transcripts. We have photochemically cross-linked to Tat peptide (37-72), a model TAR duplex substituted at U23 in the bulge by 4-thioU. We have identified the cross-linked amino acid as Arg55 in the basic region of the Tat peptide by use of a combination of proteolytic digestions and MALDI-TOF mass spectrometric analysis. The identification also required use of a synthetic Tat peptide containing a site-specific, uniformly 13C and 15N isotopically labeled arginine. We also describe a new chemical procedure for obtaining site-specific cross-links to Tat via the use of 2'-beta-alanyl U-substituted TAR and the amino-specific reagent dithiobis(succinimidyl propionate). U23-2'-functionalized TAR was shown to cross-link uniquely to Lys51 in the basic region of Tat, whereas other sites in the upper and lower stems of TAR (U35, U38, and U42) showed cross-linking only to the N-terminus of Tat peptide (37-72). U40 cross-linked to both Lys51 and the N-terminus of the peptide. The results help to establish a preliminary model of the binding of Tat peptide to the major groove of TAR RNA.
Affinity Labels↗
Secondary adrenal failure in a young woman presenting as hypoglycaemic coma.
Explore the source record for details and available documents.
Adrenal Insufficiency↗
A comparison of dressings in the management of surgical abdominal wounds.
This prospective randomised trial compared the performance of three dressing protocols in the management of 36 dehisced surgical abdominal wounds: a standard alginate; a gauze moistened with sodium hypochlorite (0.05%); and a combine dressing pad. Outcomes assessed were: healing time (cm2 per day and cm3 per day), patient comfort (pain and satisfaction) and cost. There were no statistically significant differences in healing rates between the three groups but there was a trend for the combine dressing pad protocol to produce a greater reduction in wound area. The combine dressing pad protocol performed well when compared with the calcium alginate in terms of healing time, patient comfort and cost. Maximum pain was significantly greater (p = 0.011) and satisfaction significantly lower among patients who received the sodium hypochlorite protocol. Costs during the in-patient phase were also substantially higher for the sodium hypochlorite protocol. Trial results support the view that sodium hypochlorite dressing protocols for surgical wounds should be abandoned.
Aged↗
Carboxy-terminal domain mediates assembly of the voltage-gated rat ether-à-go-go potassium channel.
The specific assembly of subunits to oligomers is an important prerequisite for producing functional potassium channels. We have studied the assembly of voltage-gated rat ether-à-go-go (r-eag) potassium channels with two complementary assays. In protein overlay binding experiments it was shown that a 41-amino-acid domain, close to the r-eag subunit carboxy-terminus, is important for r-eag subunit interaction. In an in vitro expression system it was demonstrated that r-eag subunits lacking this assembly domain cannot form functional potassium channels. Also, a approximately 10-fold molar excess of the r-eag carboxy-terminus inhibited in co-expression experiments the formation of functional r-eag channels. When the r-eag carboxy-terminal assembly domain had been mutated, the dominant-negative effect of the r-eag carboxy-terminus on r-eag channel expression was abolished. The results demonstrate that a carboxy-terminal assembly domain is essential for functional r-eag potassium channel expression, in contrast to the one of Shaker-related potassium channels, which is directed by an amino-terminal assembly domain.
Amino Acid Sequence↗
Toxin I, but not 4-aminopyridine, blocks the late inhibitory component of the dorsal root reflex in an isolated preparation of rat spinal cord.
Bursts of spontaneous antidromic dorsal root action potentials, and evoked dorsal root reflexes (DRR), have been recorded from lumbar roots of isolated spinal cord preparations of rats weighing 70-90 g. The pattern of dorsal root activity was similar to that reported for isolated cord preparations from hamsters, but the frequency of spontaneous dorsal root activity was approximately 10 times slower in the rat. Toxin I and 4-aminopyridine (4-AP) both increased the frequency of spontaneous dorsal root activity. The threshold concentration of 4-AP was 1 microM, with EC50 at 20 microM. Insufficient Toxin I was available to reach a maximal response, but the threshold concentration for producing an increase in spontaneous activity was 0.1 microM, and the curve appeared to be parallel to that of 4-AP. The patterns of spontaneous dorsal root activity in the presence of 4-AP and Toxin I differed. In 4-AP bursts of large amplitude action potentials were followed by periods of depressed activity lasting up to 500 ms, whereas in Toxin I bursts of large amplitude action potentials caused no change in the continuously firing small amplitude action potentials. DRR evoked by stimulation of adjacent dorsal roots also showed differences in the presence of 4-AP and Toxin I. In 4-AP the excitatory phase of the reflex was followed by a period of depressed activity lasting up to 500 ms. This was was reduced or absent in the presence of Toxin I. Paired pulse stimulation confirmed the presence of inhibition in 4-AP, and its reduction in Toxin I. Examination of the pattern of spontaneous dorsal root activity following dorsal root stimulation showed strong oscillatory activity in the presence of 4-AP, but little such activity in the presence of Toxin I. It was concluded that the actions of 4-AP and Toxin I on the isolated preparation of rat spinal cord are similar in that both cause an increase in the spontaneous dorsal root firing rate, but that Toxin I also blocks the period of inhibition which follows bursts of large amplitude action potentials.
4-Aminopyridine↗
Structure of the cyclin-dependent kinase inhibitor p19Ink4d.
In cancer, the biochemical pathways that are dominated by the two tumour-suppressor proteins, p53 and Rb, are the most frequently disrupted. Cyclin D-dependent kinases phosphorylate Rb to control its activity and they are, in turn, specifically inhibited by the Ink4 family of cyclin-dependent kinase inhibitors (CDKIs) which cause arrest at the G1 phase of the cell cycle. Mutations in Rb, cyclin D1, its catalytic subunit Cdk4, and the CDKI p16Ink4a, which alter the protein or its level of expression, are all strongly implicated in cancer. This suggests that the Rb 'pathway' is of particular importance. Here we report the structure of the p19Ink4d protein, determined by NMR spectroscopy. The structure indicates that most mutations to the p16Ink4a gene, which result in loss of function, are due to incorrectly folded and/or insoluble proteins. We propose a model for the interaction of Ink4 proteins with D-type cyclin-Cdk4/6 complexes that might provide a basis for the design of therapeutics against cancer. The sequences of the Ink4 family of CDKIs are highly conserved
Amino Acid Sequence↗
Crystal structure of a small G protein in complex with the GTPase-activating protein rhoGAP.
Small G proteins transduce signals from plasma-membrane receptors to control a wide range of cellular functions. These proteins are clustered into distinct families but all act as molecular switches, active in their GTP-bound form but inactive when GDP-bound. The Rho family of G proteins, which includes Cdc42Hs, activate effectors involved in the regulation of cytoskeleton formation, cell proliferation and the JNK signalling pathway. G proteins generally have a low intrinsic GTPase hydrolytic activity but there are family-specific groups of GTPase-activating proteins (GAPs) that enhance the rate of GTP hydrolysis by up to 10(5) times. We report here the crystal structure of Cdc42Hs, with the non-hydrolysable GTP analogue GMPPNP, in complex with the GAP domain of p50rhoGAP at 2.7A resolution. In the complex Cdc42Hs interacts, mainly through its switch I and II regions, with a shallow pocket on rhoGAP which is lined with conserved residues. Arg 85 of rhoGAP interacts with the P-loop of Cdc42Hs, but from biochemical data and by analogy with the G-protein subunit G(i alpha1), we propose that it adopts a different conformation during the catalytic cycle which enables it to stabilize the transition state of the GTP-hydrolysis reaction.
Arginine↗
Psychological distress in patients with hyperprolactinaemia.
OBJECTIVE: In addition to the physical symptoms of galactorrhoea and amenorrhoea, hyperprolactinaemia in women is also reported to be associated with psychological symptoms. Previous studies have found an increased incidence of depression, anxiety and hostility in female patients with hyperprolactinaemia. In this study, psychological symptoms were assessed in a large population of patients and symptom scores were compared between patients with definite evidence of pituitary adenoma on high-resolution CT scanning and those without, who were presumed to have idiopathic or 'functional' hyperprolactinaemia. DESIGN: Postal survey: population-control study of female patients with hyperprolactinaemia. PATIENTS: Sixty-five women with hyperprolactinaemia were compared with a control group of 26 women with normoprolactinaemic pituitary disease (acromegaly or nonfunctioning pituitary adenoma). The hyperprolactinaemic patients were subdivided according to whether a pituitary adenoma was visible on high-resolution CT scanning (39 patients) or whether they had normal CT scans, in which case they were categorized as having idiopathic or 'functional' hyperprolactinaemia (26 patients). MEASUREMENTS: Patients were sent 2 questionnaires, the Hospital Anxiety and Depression (HAD) Scale and the 90-item Symptom Checklist (SCL-90), to assess psychological wellbeing. RESULTS: Overall, 54% of hyperprolactinaemic patients were found to have definite or borderline anxiety as judged by HAD scores, compared with 27% of normoprolactinaemic control patients. Those with normal CT scans were significantly more likely to have definite or borderline anxiety (73% of patients) than those with CT evidence of a pituitary tumour causing their hyperprolactinaemia (41%, P < 0.003), despite similar levels of serum prolactin. A similar increased proportion of hyperprolactinaemic patients scored highly on the anxiety component of the SCL-90, although mean scores were not different from controls. No differences were seen in scores for depression, but both subgroups of hyperprolactinaemic patients scored more highly than controls for hostility on the SCL-90 questionnaire. CONCLUSION: These findings confirm the presence of significant anxiety in a proportion of women with hyperprolactinaemia. Hyperprolactinaemic women with no abnormality on CT scans displayed more psychological distress than those with definite pituitary microadenomas. These results may provide insight into the pathogenesis of 'functional' hyperprolactinaemia.
Adenoma↗
Amphiphysin heterodimers: potential role in clathrin-mediated endocytosis.
Amphiphysin (Amph) is a src homology 3 domain-containing protein that has been implicated in synaptic vesicle endocytosis as a result of its interaction with dynamin. In a screen for novel members of the amphiphysin family, we identified Amph2, an isoform 49% identical to the previously characterized Amph1 protein. The subcellular distribution of this isoform parallels Amph1, both being enriched in nerve terminals. Like Amph1, a role in endocytosis at the nerve terminal is supported by the rapid dephosphorylation of Amph2 on depolarization. Importantly, the two isoforms can be coimmunoprecipitated from the brain as an equimolar complex, suggesting that the two isoforms act in concert. As determined by cross-linking of brain extracts, the Amph1-Amph2 complex is a 220- to 250-kDa heterodimer. COS cells transfected with either Amph1 or Amph2 show greatly reduced transferrin uptake, but coexpression of the two proteins rescues this defect, supporting a role for the heterodimer in clathrin-mediated endocytosis. Although the src homology 3 domains of both isoforms interact with dynamin, the heterodimer can associate with multiple dynamin molecules in vitro and activates dynamin's GTPase activity. We propose that it is an amphiphysin heterodimer that drives the recruitment of dynamin to clathrin-coated pits in endocytosing nerve terminals.
Amino Acid Sequence↗
Prognostic factors in esophageal cancer.
Clinical and pathologic factors relevant to the prognosis of esophageal cancer are reviewed in this article. Clinical factors discussed include endoscopic, radiologic, and surgical findings. The importance of Barrett's esophagus and the role of endoscopic screening in the diagnosis of dysplasia and the prevention of adenocarcinoma are evaluated. Pathologic factors include the traditional ones of tumor type, stage, and grade as well as newer tumor markers related to DNA content, rate of cell proliferation, oncogenes, and tumor suppressor genes.
DNA, Neoplasm↗
The effect of an accelerated immunisation schedule on pertussis in England and Wales.
Notifications of pertussis in England and Wales have fallen dramatically from 65 810 during the epidemic year of 1982 to 3963 cases during the epidemic year of 1994, as vaccine coverage has risen. The incidence of pertussis has declined in all ages, including babies under 3 months of age who would have been at risk of disease from older siblings vaccinated under the accelerated schedule introduced in 1990 if immunity induced as result of this schedule had been short lived. To document the efficacy of the current whole cell vaccine under the accelerated schedule an enhanced surveillance scheme based on laboratory confirmed cases of pertussis was set up in 1994. Three deaths occurred in infants with confirmed pertussis, all of whom were under 8 weeks of age and unvaccinated. The overall vaccine efficacy for those over 6 months and under 5 years of age was 94%. This estimate may be inflated, as a number of biases could lead to the underascertainment of cases in vaccinated children, but it is similar to previous estimates obtained for children of the same age vaccinated under the 3, 5, and 10 month schedule. Vaccine efficacy was 89% for children aged over 5 and under 15 years. The enhanced surveillance scheme will enable us to monitor the duration of protection under the accelerated schedule and evaluate the continuing impact of pertussis infection.
Adolescent↗
Control of p53 expression by adenovirus 12 early region 1A and early region 1B 54K proteins.
The level of p53 is markedly increased in human cells in response to expression of the Ad12 E1A proteins and, quite separately, to the Ad12 E1B 54K protein. The behaviour of p53 in these two circumstances has been examined using A549 cells infected with Ad12 dl620 (a mutant virus which does not express the larger E1B protein and is replication-defective) and human skin fibroblasts expressing the Ad12 E1B 54K protein (HSF 54K). In normal and E1A-expressing A549 cells, p53 is located predominantly in the nucleus, whereas in the HSF 54K cells it is primarily cytoplasmic as is the Ad12 E1B 54K protein. The half-life of p53 is increased in Ad12 dl620-infected A549 cells from about 10 min (in uninfected cells) to 2 hr. The half-life of p53 in HSF 54K cells is even longer-probably in excess of 48 hr. The capacity of p53 to regulate transcription was assessed using a transfected CAT construct linked to p53-responsive elements. p53 transcriptional activity was very low in the HSF 54K cells and in human embryo kidney cells expressing the Ad12 E1B 54K protein (and p53) at high level. It was, however, dramatically increased in response to the p53 expressed as a result of E1A expression. Additionally, MDM2 was present at low level in the HSF 54K cell lines, whilst, as we have previously shown, it is overexpressed in response to infection with Ad12 dl620. We conclude that there are two distinct mechanisms for up-regulation of p53 attributable to the adenovirus E1 proteins. When E1A only is present the p53 is nuclear and transcriptionally active and can probably induce apoptosis in the absence of the E1B 19K protein. When the E1B 54K protein is present, however, p53 is transcriptionally inactive and does not induce apoptosis.
Adenovirus E1A Proteins↗
Novel effects of dendrotoxin homologues on subtypes of mammalian Kv1 potassium channels expressed in Xenopus oocytes.
We have examined the effects of two DTX homologues, toxin I and toxin K, on Kv1.1, Kv1.2 and Kv1.6 channels expressed in Xenopus oocytes. Toxin I blocked all three channels; in contrast, toxin K was selective for Kv1.1. Both toxins slowed channel activation and inactivation kinetics with 10 nM toxin I approximately doubling activation and inactivation time constants of Kv1.1. For the first time, we have demonstrated the selectivity of a DTX homologue for a single cloned Kv1 channel and suggest that these toxins may sterically hinder the conformational changes that occur during channel gating.
Animals↗
Malignant rhabdoid tumor of the colon. Report of a case with molecular analysis.
PURPOSE: Malignant rhabdoid tumors were first described in the kidney as a rare variant of Wilms' tumor with a "rhabdomyosarcomatoid" pattern and a particularly poor prognosis. Further studies have demonstrated these neoplasms as a distinct clinicopathologic entity. Subsequently, tumors with a similar histologic appearance, demonstrating the "rhabdoid" cells, have been found in a variety of extrarenal sites. METHODS: We report here a case of malignant rhabdoid tumor of the colon studied with selected molecular techniques. RESULTS AND CONCLUSIONS: This tumor demonstrated several unusual findings for malignant rhabdoid tumors of renal or extrarenal sites, including aneuploidy by flow cytometric analysis and a positive nuclear immunohistochemical staining for p53 protein, which suggests presence of p53 gene mutation. DNA analyses, however, failed to demonstrate the presence of point mutation in any of the ras family genes.
Aged↗
Intensive chemotherapy for adult acute lymphoblastic leukaemia given with or without granulocyte-macrophage colony stimulating factor.
Twenty-six patients with newly diagnosed ALL (age range 15-49 years, median 32 years) received treatment comprising: cycles 1 and 2: adriamycin 30 mg/m2 days 1-3, vincristine: 2 mg days 1, 8, and 15, with prednisolone 40 mg daily, given until complete remission (CR). L-asparaginase 10000 units/m2, days 1-14, was given only with the first cycle. Cycle 3 consisted of 100 mg/m2 etoposide orally, days 1-5, and 1 gm/m2 bd cytosine arabinoside (ara-C) days 1-5. Cycles 1-3 were then repeated. Intrathecal methotrexate (MTX) 12.5 mg was given on day 1 of each treatment cycle. The first 12 consecutive patients received this chemotherapy alone, the subsequent 14 received, in addition, 3 micrograms/kg GM-CSF subcutaneously, from day 4 of cycles 1,2,4 and 5 (and from day 6 of cycles 3 and 6) until the absolute neutrophil count had reached 0.5 x 10(9)/1. All patients in whom CR was achieved then received prophylactic cranial irradiation. With the exception of those with T-ALL, this was followed by oral maintenance therapy consisting of 6-mercaptopurine, MTX, and cyclophosphamide for 3 years. Patients receiving GM-CSF did not have shorter intercycle times or a lower incidence of documented infections than those who did not receive it. The CR rate was 89% overall-uninfluenced by GM-CSF, but higher than that achieved previously at St Bartholomew's Hospital in an equivalent age-group.
Adolescent↗