Biomedical subjects

J Allen

Publications and source records attributed to J Allen.

At least 19 recordsLinked to original sources

PubMed2006

Autonomic dysfunction in dementia.

BACKGROUND: There are no studies of autonomic function comparing Alzheimer's disease (AD), vascular dementia (VAD), dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). AIMS: To assess cardiovascular autonomic function in 39 patients with AD, 30 with VAD, 30 with DLB, 40 with PDD and 38 elderly controls by Ewing's battery of autonomic function tests and power spectral analysis of heart rate variability. To determine the prevalence of orthostatic hypotension and autonomic neuropathies by Ewing's classification. RESULTS: There were significant differences in severity of cardiovascular autonomic dysfunction between the four types of dementia. PDD and DLB had considerable dysfunction. VAD showed limited evidence of autonomic dysfunction and in AD, apart from orthostatic hypotension, autonomic functions were relatively unimpaired. PDD showed consistent impairment of both parasympathetic and sympathetic function tests in comparison with controls (all p<0.001) and AD (all p<0.03). DLB showed impairment of parasympathetic function (all p<0.05) and one of the sympathetic tests in comparison with controls (orthostasis; p = 0.02). PDD had significantly more impairment than DLB in some autonomic parameters (Valsalva ratio: p = 0.024; response to isometric exercise: p = 0.002). Patients with VAD showed impairment in two parasympathetic tests (orthostasis: p = 0.02; Valsalva ratio: p = 0.08) and one sympathetic test (orthostasis: p = 0.04). These results were in contrast with AD patients who only showed impairment in one sympathetic response (orthostasis: p = 0.004). The prevalence of orthostatic hypotension and autonomic neuropathies was higher in all dementias than in controls (all p<0.05). CONCLUSION: Autonomic dysfunction occurs in all common dementias but is especially prominent in PDD with important treatment implications.

Aged↗

PubMed2006

Cancer-related fatigue: A critical appraisal.

This aim of this systematic review was to determine the prevalence and pattern of cancer-related fatigue (CRF), and identify factors associated with its development. Relevant literature was identified through an electronic database search using specified keywords. Included studies investigated CRF in adult cancer patients using a multidimensional fatigue measure. The methodological quality was assessed using six published standards. CRF is apparent both during and after anti-cancer therapy, however, the prevalence of CRF varied between studies. The variables associated with the development and persistence of CRF remain to be identified. Inconsistencies were evident in the pattern of CRF and its associated factors. This is likely to have arisen from the inherent difficulties in the measurement of a subjective sensation, further complicated by the myriad of outcome measures used. More methodologically sound research; assessing CRF from the commencement of therapy, considering all pertinent variables is needed.

Antineoplastic Agents↗

PubMed2006

Pulse oximetry in very low birth weight infants: can oxygen saturation be maintained in the desired range?

OBJECTIVE: To determine if a change in the pulse oximeter goal range and high alarm limit for oxygen saturation (SpO2) alters the distribution of SpO2 for premature infants in oxygen. STUDY DESIGN: This was a prospective, observational analysis. For group 1 (February 2002 to April 2002, n = 23), pulse oximeter alarms were set at 80% (low) and 96% (high), and the goal range was 90-95%. For group 2 (May 2002 to August 2003, n = 49), the high alarm was lowered to 94%, and the goal range was 88 to 94%. The SpO2 values for 24 h were downloaded from Nellcor pulse oximeters during the two periods and the percent time within, above and below the goal range was derived and compared. RESULTS: Groups were similar except for use of post-natal steroids (group 2 > 1). The percent time within (57.7+/-9.8 vs 59.4+/-12.4%), above (15.4+/-10.6 vs 14+/-9.4%) and below (26.9+/-9.7 vs 26.6+/-10.2%) the goal range was similar for groups 1 and 2, respectively. However, the percent time with SpO2 <80% increased significantly for group 2 (4.0+/-2.7 vs 1.9+/-1.4%). CONCLUSIONS: Changes in pulse oximeter policy and alarms in labile, sick premature infants need evaluation for their effects on the distribution of SpO2 values before routine use.

Female↗

PubMed2005

Upper limits on a stochastic background of gravitational waves.

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of omega0 < 8.4 x 10(-4) in the 69-156 Hz band is approximately 10(5) times lower than the previous result in this frequency range.

Journal Article↗

PubMed2005

Fatigue in gynaecological cancer patients: a pilot study.

RATIONALE: Fatigue is a frequent complaint of women with cancer. However, the incidence of fatigue has not been well studied, in particular gynaecological cancer, which despite its prevalence has received minimal investigation. GOALS OF WORK: The study aims were (1) to explore the symptoms experienced in a gynaecological cancer population, primarily fatigue and (2) to determine the acceptability of a fatigue questionnaire for use in a longitudinal survey. PATIENTS AND METHODS: Over the course of 1 month, women with gynaecological cancer attending a Regional Cancer Centre completed a demographic and symptom questionnaire and the Multidimensional Fatigue Symptom Inventory-Short Form (MFSI-SF). MAIN RESULTS: Of the 32 individuals approached, 30 agreed to participate (mean age, 61 years; the most common treatment received was surgery followed by chemotherapy n=11; mean time from commencement of treatment, including surgery = 3 months). All participants completed the MFSI-SF. Tiredness was the most commonly reported symptom, experienced by 90% of subjects and the most frequently stated worst symptom, reported by 23.3%. Furthermore, 23 of 27 subjects reported that tiredness interfered completely with their daily living. The MFSI-SF mean total fatigue score was 14.4 (SD 15.9), ranging from -15 to 50. The possible total fatigue score ranges from -24 to 96. CONCLUSION: Despite the heterogeneous nature of the group, all participants completed the MFSI-SF. The study suggests that fatigue could be a problem for this population group. Thus, a longitudinal survey using the MFSI-SF to investigate the phenomenon further would appear feasible and justified.

Activities of Daily Living↗

PubMed2005

Phase I trial of liposomal encapsulated doxorubicin (Myocet; D-99) and weekly docetaxel in advanced breast cancer patients.

BACKGROUND: We conducted a phase I trial to determine the safety and maximum tolerated dose (MTD) of non-pegylated liposome-encapsulated doxorubicin (Myocet; D-99) administered with weekly docetaxel in metastatic breast cancer (MBC) patients. PATIENTS AND METHODS: Twenty-one patients with no prior chemotherapy for MBC received D-99 (60 or 50 mg/m2) intravenously (i.v.) on day 1 and escalating doses of docetaxel (25, 30 and 35 mg/m2 i.v. on days 1 and 8 in cohorts of three to six patients. Treatment cycles were repeated every 21 days for a maximum of six cycles. RESULTS: The maximum tolerated dose (MTD) was 50 mg/m2 of D-99 in combination with 25 mg/m2 of weekly docetaxel. The most common grade 4 toxicity was neutropenia that occurred in 42 (41%) of treatment cycles, with 10 hospitalizations for febrile neutropenia. Serious protocol-defined cardiac events occurred in three (14%) patients, with two (10%; 95% confidence interval [CI] 1% to 30%) developing congestive heart failure (CHF) after a total cumulative anthracycline dose (adjuvant doxorubicin + D-99) of 540 mg/m2. CONCLUSIONS: D-99 in combination with weekly docetaxel, at the doses and schedule as administered in this trial, is not recommended for phase II testing. Additional trials, using different doses and schedules, are required to evaluate the potential side-effects and efficacy of D-99 and docetaxel.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

Whole genomewide linkage screen for neural tube defects reveals regions of interest on chromosomes 7 and 10.

Neural tube defects (NTDs) are the second most common birth defects (1 in 1000 live births) in the world. Periconceptional maternal folate supplementation reduces NTD risk by 50-70%; however, studies of folate related and other developmental genes in humans have failed to definitively identify a major causal gene for NTD. The aetiology of NTDs remains unknown and both genetic and environmental factors are implicated. We present findings from a microsatellite based screen of 44 multiplex pedigrees ascertained through the NTD Collaborative Group. For the linkage analysis, we defined our phenotype narrowly by considering individuals with a lumbosacral level myelomeningocele as affected, then we expanded the phenotype to include all types of NTDs. Two point parametric analyses were performed using VITESSE and HOMOG. Multipoint parametric and nonparametric analyses were performed using ALLEGRO. Initial results identified chromosomes 7 and 10, both with maximum parametric multipoint lod scores (Mlod) >2.0. Chromosome 7 produced the highest score in the 24 cM interval between D7S3056 and D7S3051 (parametric Mlod 2.45; nonparametric Mlod 1.89). Further investigation demonstrated that results on chromosome 7 were being primarily driven by a single large pedigree (parametric Mlod 2.40). When this family was removed from analysis, chromosome 10 was the most interesting region, with a peak Mlod of 2.25 at D10S1731. Based on mouse human synteny, two candidate genes (Meox2, Twist1) were identified on chromosome 7. A review of public databases revealed three biologically plausible candidates (FGFR2, GFRA1, Pax2) on chromosome 10. The results from this screen provide valuable positional data for prioritisation of candidate gene assessment in future studies of NTDs.

Chromosomes, Human, Pair 10↗

PubMed2005

Chronomics, neuroendocrine feedsidewards and the recording and consulting of nowcasts--forecasts of geomagnetics.

A multi-center four-hourly sampling of many tissues for 7 days (00:00 on April 5-20:00 to April 11, 2004), on rats standardized for 1 month in two rooms on antiphasic lighting regimens happened to start on the day after the second extremum of a moderate double magnetic storm gauged by the planetary geomagnetic Kp index (which at each extremum reached 6.3 international [arbitrary] units) and by an equatorial index Dst falling to -112 and -81 nT, respectively, the latter on the first day of the sampling. Neuroendocrine chronomes (specifically circadian time structures) differed during magnetically affected and quiet days. The circadian melatonin rhythm had a lower MESOR and lower circadian amplitude and tended to advance in acrophase, while the MESOR and amplitude of the hypothalamic circadian melatonin rhythm were higher during the days with the storm. The circadian parameters of circulating corticosterone were more labile during the days including the storm than during the last three quiet days. Feedsidewards within the pineal-hypothalamic-adrenocortical network constitute a mechanism underlying physiological and probably also pathological associations of the brain and heart with magnetic storms. Investigators in many fields can gain from at least recording calendar dates in any publication so that freely available information on geomagnetic, solar and other physical environmental activity can be looked up. In planning studies and before starting, one may gain from consulting forecasts and the highly reliable nowcasts, respectively.

Animals↗

PubMed2005

Genetic segregation of spontaneous erosive arthritis and generalized autoimmune disease in the BXD2 recombinant inbred strain of mice.

The BXD2 strain of mice is one of approximately 80 BXD recombinant inbred (RI) mouse strains derived from an intercross between C57BL/6J (B6) and DBA/2J (D2) strains. We have discovered that adult BXD2 mice spontaneously develop generalized autoimmune disease, including glomerulonephritis (GN), increased serum titres of rheumatoid factor (RF) and anti-DNA antibody, and a spontaneous erosive arthritis characterized by mononuclear cell infiltration, synovial hyperplasia, and bone and cartilage erosion. The features of lupus and arthritis developed by the BXD2 mice segregate in F2 mice generated by crossing BXD2 mice with the parental B6 and D2 strains. Genetic linkage analysis of the serum levels of anti-DNA and RF by using the BXD RI strains shows that the serum titers of anti-DNA and RF were influenced by a genetic locus on mouse chromosome (Chr) 2 near the marker D2Mit412 (78 cm, 163 Mb) and on Chr 4 near D4Mit146 (53.6 cm, 109 Mb), respectively. Both loci are close to the B-cell hyperactivity, lupus or GN susceptibility loci that have been identified previously. The results of our study suggest that the BXD2 strain of mice is a novel model for complex autoimmune disease that will be useful in identifying the mechanisms critical for the immunopathogenesis and genetic segregation of lupus and erosive arthritis.

Albuminuria↗

PubMed2005

The basement membrane zone and dermal extracellular matrix in erosive lichen planus of the vulva: an immunohistochemical study demonstrating altered expression of hemidesmosome components and anchoring fibrils.

Histopathology demonstrates disruption of the basal layer of the epidermis in lichen planus (LP) and altered expression of basement membrane zone (BMZ) components occurs in cutaneous and oral LP. This is the first study in erosive LP of the vulva to investigate the expression of components of the BMZ and extracellular matrix by indirect immunofluorescence. Six biopsies from lesional vulval erosive LP were compared with two biopsies from normal vulva and five biopsies from normal skin. In erosive vulval LP there was widespread disruption of several BMZ components compared to normal skin. The hemidesmosome antigens were disrupted and attenuated, or absent. Expression of lamina lucida proteins and anchoring filaments also showed some alteration. Lamina densa components were altered and in particular there was very marked thickening, streaking and fragmentation of the anchoring fibrils. Some dermal extracellular matrix proteins were increased. This study has demonstrated widespread damage to the BMZ in erosive LP of the vulva, in particular the hemidesmosomes (alpha6beta4 integrin, BP230, BP180) and anchoring fibrils (collagen VII). This suggests an alteration in antigenic expression in the BMZ that may lead to exposure of epitopes and thus make these proteins vulnerable to attack by autoantibodies.

Autoantigens↗

PubMed2005

Erosive lichen planus of the vulva: weak circulating basement membrane zone antibodies are present.

The objective of this study was to investigate whether circulating basement membrane zone (BMZ) antibodies are present in erosive lichen planus (LP) of the vulva. In total, 56 consecutive women with biopsy-confirmed erosive LP of the vulva were recruited from a vulval clinic in a district general hospital and teaching hospital in Oxfordshire. Indirect immunofluorescence (IgG and IgA) was performed on 56 sera, and 15 were tested to IgG subclasses (1-4). Immunoblotting was carried out on salt-split and urea-extracted epidermal skin extracts on 11. The main outcome measure was the presence or absence of staining at the BMZ. Of the 56 sera, 34 (61%) had weak (neat or 1 : 5) epidermal-binding BMZ antibodies (25 had IgG, 5 had IgA, 4 had both IgG and IgA). All 15 sera tested to IgG showed epidermal binding to one or more IgG subclasses: IgG1 (7 sera), IgG2 (7), IgG3 (7) and IgG4 (0). Immunoblotting identified IgG antibodies to bullous pemphigoid (BP)180 (10/11) and BP230 (2/11). The majority (61%) of patients with vulval erosive LP had circulating serum IgG BMZ antibodies, chiefly reacting with BP180. There was subclass restriction of the IgG response to IgG1, 2 and 3. The significance of these antibodies is uncertain, but they may be a marker for the disease.

Adult↗

PubMed2005

Regulated expression of putative membrane progestin receptor homologues in human endometrium and gestational tissues.

Rapid non-genomic actions of progesterone are implicated in many aspects of female reproduction. Recently, three human homologues of the fish membrane progestin receptor (mPR) have been identified. We combined bioinformatic analysis with expression profiling to define further the role of these mPRs in human reproductive tissues. Sequence analysis confirmed that the mPRs belong to a larger, highly conserved family of proteins, termed 'progestin and adiponectin receptors' (PAQRs). A comparison of the expression of mPR transcripts with that of two related PAQR family members, PAQRIII and PAQRIX, in cycling endometrium and pregnancy tissues revealed markedly divergent expression levels and profiles. For instance, endometrial expression of mPRalpha and gamma and PAQRIX was cycle-dependent whereas the onset of parturition was associated with a marked reduction in myometrial mPRalpha and beta transcripts. Interestingly, mPRalpha and PAQRIX were most highly expressed in the placenta, and the tissue expression levels of both genes correlated inversely with that of the nuclear PR. Phylogenetic analysis demonstrated that PAQRIX belongs to the mPR subgroup of proteins. We also validated a polyclonal antibody raised against the carboxy-terminus of human mPRalpha. Immunohistochemical analysis demonstrated more intense immunoreactivity in placental syncytiotrophoblasts than in endometrial glands or stroma. The data suggest important functional roles for mPRalpha, and possibly PAQRIX, in specific reproductive tissues, particularly those that express low levels of nuclear PR.

Adult↗

PubMed2004

Autonomic function assessed by heart rate variability is normal in Alzheimer's disease and vascular dementia.

Heart rate variability (HRV) is a sensitive method for the assessment of autonomic function and requires little cooperation from the subject, making it suitable for use in dementia. Preliminary studies have suggested that HRV may be impaired in Alzheimer's disease (AD). HRV has not been studied in vascular dementia (VAD). We investigate autonomic function in AD and VAD, using power spectral analysis of HRV. One hundred and fourteen participants were evaluated (14 AD, 20 VAD and 80 controls). The resting ECG was recorded for 5 min with participants in the supine position. Power spectral analysis used to obtain spectral bands in the very-low-frequency (<0.04 Hz), low-frequency (0.04-0.15 Hz) and high-frequency (0.15-0.40 Hz) bands and total spectral power (<0.40 Hz) according to international HRV guidelines. There were no differences in HRV in patients with AD or VAD when compared with controls.

Aged↗

PubMed2004

Phase I dose-escalation trial of irinotecan with continuous infusion 5-FU first line, in metastatic colorectal cancer.

This single-centre phase I trial was designed to determine the maximum tolerated dose of irinotecan and the recommended dose to use in combination with a fixed dose of 5-fluorouracil (5-FU) administered as a protracted venous infusion, for the first-line treatment of metastatic colorectal cancer (CRC). Tolerability and efficacy were secondary end points. In all, 22 patients, median age 57 years, were treated with escalating, weekly doses of irinotecan (50, 75, 100 and 85 mg m(-2)) in combination with 250 mg m(-2) 5-FU administered as a continuous infusion. All patients had measurable disease. The combination was well tolerated up to an irinotecan dose of 75 mg m(-2). However, three out of five patients at the 100 mg m(-2) irinotecan dose level had their dose reduced due to multiple grade 2 toxicities, and eventually one patient stopped treatment due to grade 3 diarrhoea and multiple grade 2 toxicities. Subsequent patients were recruited at an irinotecan dose level of 85 mg m(-2). The overall response rate was 55%, comprising one complete and 11 partial responses (PRs). Six patients also achieved sustained stable disease (SD), giving a clinical benefit (complete response/PR/SD) response of 82%. The median duration of response was 238 days (8.5 months) and median time to progression was 224 days (8.0 months). Two patients who achieved PRs underwent partial hepatectomies. Thus, irinotecan (85 mg m(-2)) combined with a continuous infusion of 5-FU (250 mg m(-2)) is an active and well-tolerated regimen for the treatment of metastatic CRC. It represents an effective treatment for patients who require close supervision and support, throughout their initial exposure to chemotherapy for this disease, and this dose combination was recommended for an ongoing phase II study.

Adult↗

PubMed2004

Age-related changes in the dynamics of potassium-evoked L-glutamate release in the striatum of Fischer 344 rats.

In the present studies we used a multisite ceramic-based microelectrode for rapid (800 ms) and low level measures of L-glutamate in vivo. We measured the amplitude and clearance rate of phasic changes in L-glutamate release produced by local application of potassium by a micropipette placed adjacent to the recording sites in the striatum of young (6 month), late middle aged (18 month) and aged (24 month) Fischer 344 rats. Our results showed that the amplitudes and clearance rates of potassium-evoked release of L-glutamate in the striatum were significantly decreased in aged rats as compared to the other age groups. In addition, the sensitivity of glutamate fibers to depolarization with potassium was significantly decreased in the aged rats as compared to young animals. Taken together, these data are consistent with age-related alterations in glutamate release dynamics, which may involve a compensatory mechanism for maintaining static glutamate concentrations within the striatum.

Aging↗

PubMed2004

Multidrug-resistant tuberculous meningitis in KwaZulu-Natal, South Africa.

Multidrug-resistant (MDR) pulmonary tuberculosis (TB) is well described in the literature. Reports of MDR TB meningitis (MDR-TBM), however, are limited to case reports and a single case series. During the period of 1999-2002, 350 patients with TBM were identified by cerebrospinal fluid culture for TB. Thirty patients (8.6%) had TB that was resistant to at least isoniazid and rifampicin. All 30 patients were included in this study. We reviewed hospital charts of the patients with MDR-TBM and describe our experience. Seventeen patients with MDR-TBM died, and, of those who were known to be alive, many experienced significant morbidity. Eighteen patients were HIV positive. Twenty-two patients had been treated for TB in the past, 3 patients had received no previous treatment for TB, and the history of TB treatment was unknown for 5 patients. The study highlights the prevalence of MDR-TBM and identifies new challenges in the management of affected patients.

Adolescent↗

PubMed2004

Alterations in the basement membrane zone in pili annulati hair follicles as demonstrated by electron microscopy and immunohistochemistry.

BACKGROUND: Pili annulati is a rare autosomal dominant inherited hair shaft abnormality in which clinical examination reveals alternating light and dark bands leading to a shiny appearance of the hair. The clinically light bands are the abnormal areas due to cavities within the cortex. The pathogenesis remains unknown. OBJECTIVES: To investigate the expression of the basement membrane zone (BMZ) components in pili annulati hair follicles of the scalp. METHODS: Transmission electron microscopy (TEM) was carried out on scalp sections of six individuals with pili annulati and six controls. Longitudinal sections of scalp tissues from four individuals with pili annulati and six normal controls were studied by immunohistochemistry with a panel of monoclonal antibodies to the following BMZ components: alpha(6)beta(4) integrin, laminin 5, LH39 antigen, laminin 1, collagen IV and collagen VII. RESULTS: Using TEM, pili annulati scalp specimens exhibited a reduplicated lamina densa in the region of the root bulb in comparison with the single thin electron-dense band in controls. Using immunohistochemistry, there was a wavy BMZ in pili annulati follicles with antibodies to components of the lamina lucida, lamina densa and anchoring fibrils, whereas the BMZ in control hair follicles was as a smooth linear band. The expression of the hemidesmosome-associated alpha(6)beta(4) integrin was linear in both pili annulati and control hair follicles. CONCLUSIONS: Our results suggest that the genetic defect may be a mutation in proteins involved in signalling and regulation of formation and degradation of the lamina densa and sublamina densa region resulting in abnormal assembly or remodelling of the BMZ.

Adult↗

PubMed2003

Development and research program for a soil-based bioregenerative agriculture system to feed a four person crew at a Mars base.

For humans to survive during long-term missions on the Martian surface, bioregenerative life support systems including food production will decrease requirements for launch of Earth supplies, and increase mission safety. It is proposed that the development of "modular biospheres"--closed system units that can be air-locked together and which contain soil-based bioregenerative agriculture, horticulture, with a wetland wastewater treatment system is an approach for Mars habitation scenarios. Based on previous work done in long-term life support at Biosphere 2 and other closed ecological systems, this consortium proposes a research and development program called Mars On Earth(TM) which will simulate a life support system designed for a four person crew. The structure will consist of 6 x 110 square meter modular agricultural units designed to produce a nutritionally adequate diet for 4 people, recycling all air, water and waste, while utilizing a soil created by the organic enrichment and modification of Mars simulant soils. Further research needs are discussed, such as determining optimal light levels for growth of the necessary range of crops, energy trade-offs for agriculture (e.g. light intensity vs. required area), capabilities of Martian soils and their need for enrichment and elimination of oxides, strategies for use of human waste products, and maintaining atmospheric balance between people, plants and soils.

Air Conditioning↗