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Biomedical subjects

M Hall

Publications and source records attributed to M Hall.

At least 91 records · Page 5Linked to original sources
PubMed1998

Low serum antimycobacterial drug levels in non-HIV-infected tuberculosis patients.

BACKGROUND: Despite the use of directly observed therapy (DOT) by tuberculosis control programs, patient treatment failure, relapse, and acquired drug resistance remain problematic in a small number. We investigated serum drug levels in non-HIV-infected tuberculosis patients who were receiving DOT by the health department and did not respond to treatment as expected. METHODS: The indications for checking levels were as follows: (1) slow clinical response or failure to convert the sputum culture within 12 weeks; (2) treatment failure, early disease relapse < 13 months since being declared cured; (3) relapse, late disease reactivation > or = 13 months since being declared cured; and (4) acquired drug resistance while receiving DOT. Baseline characteristics of control subjects who responded to therapy as expected were compared. Venous blood for analysis was obtained at 2 h after directly observed ingestion and measured by high-performance liquid chromatography. RESULTS: Twenty-four patients receiving daily or twice-weekly standard therapy with isoniazid (INH, 300 or 900 mg) and rifampin (RMP, 600 mg) were identified; 22 had drug levels evaluated at 2 h. For INH, 15 of 22 patients (68%) had levels less than the reported target range. For RMP, 14 of 22 patients (64%) had low levels. Among the 14 patients receiving INH, 900 mg, and RMP, 600 mg, 4 (29%) had very low levels of both. Use of a combination INH/RMP tablet was associated with lower INH levels (p=0.04); however, RMP levels were higher (p<0.02). Alcohol use was associated with significantly higher RMP (p<0.01) serum concentrations. CONCLUSIONS: Important questions remain concerning the utility and timing of serum drug measurements. However, if a patient is not responding to therapy as expected and one is assured that the Mycobacterium tuberculosis organism is susceptible to the drugs given and that the patient is taking the medication as prescribed, drug level monitoring should be considered.

Adult↗
PubMed1998

Genetic patterning of the posterior neuropore region of curly tail mouse embryos: deficiency of Wnt5a expression.

The mouse mutant curly tail (ct) develops tail flexion defects and spina bifida as the result of delayed or failed closure of the posterior neuropore (PNP). With the aim of identifying genes involved in the chain of events resulting in defective neurulation, which can be detected at day 10.5 of development, we examined the expression patterns of a number of genes implicated in patterning of axial structures, mesoderm and neuroepithelium. The genes analyzed were Shh, HNF3alpha, HNF3beta, Brachyury, Hoxb1, Evx1, Fgf8, Wnt5a and Wnt5b. No differences could be detected between non-mutant embryos and ct/ct embryos with normal PNP size for any of these genes. Comparisons between ct/ct embryos with enlarged PNP and phenotypically normal ct/ct or nonmutant embryos showed differences only for Wnt5a. Expression of this gene was greatly reduced in the ventral caudal mesoderm and hindgut endoderm. Analysis of younger embryos revealed that prior to the stage at which embryos at risk of developing neural tube defects can be detected, the same proportion of ct/ct embryos shows reduced Wnt5a expression. The proportion of embryos showing reduced expression and almost undetectable expression of Wnt5a reflects the proportions of tail defects and spina bifida seen at later stages. We suggest that deficiency of Wnt5a signaling in the ventral caudal region tissues is an important component of the mechanism of development of the defects in affected curly tail mutant mice, and that it is causally related to decreased cell proliferation within the ventral caudal region. A possible relationship between decreased Wnt5a expression and reduced levels of heparan sulphate proteoglycan is discussed.

Animals↗
PubMed1998

Palliative terminal cancer care in community hospitals and a hospice: a comparative study.

BACKGROUND: Despite palliative care being an accepted role of community hospitals, there is little quantitative evidence of the type of care provided. AIM: To obtain quantitative data comparing palliative cancer care provided in 12 community hospitals in 10 towns (approximately 350 medical beds) and in a consultant-led purpose-built hospice (12 beds). METHOD: Retrospective medical and nursing case note analysis over one year of cancer deaths in the former Exeter Health District. RESULTS: A total of 171 community hospital and 116 hospice casenotes were analysed. Hospice patients had significantly different reasons for admission compared with community hospital patients (P < 0.001), with pain and symptom control being more frequent and terminal nursing care less frequent reasons for admission to the hospice. Community hospital length of stay was significantly longer than hospice length of stay (P = 0.002; mean community hospital stay 16 days, mean hospice stay eight days). Symptoms on admission differed significantly. Drug prescribing on admission and at death and indications of active treatment of symptoms were broadly similar. Community hospital patients received more investigations than hospice patients, linked to the observation that around one in ten community hospital patients were admitted for investigation and active treatment. Community hospital medical notes were significantly less likely to meet minimum quality standards than were hospice notes (81/171 vs. 18/116; P < 0.001), with major deficiencies in the areas of examination, progress reporting, and absence of confirmation of death. CONCLUSIONS: This study confirms the role of community hospitals in palliative terminal cancer care. Differences in care between community hospitals and a hospice have been demonstrated that may reflect either different admission populations to each setting or differences in the way care was delivered.

Hospices↗
PubMed1998

Dying from cancer in community hospitals or a hospice: closest lay carers' perceptions.

BACKGROUND: Despite there being around 400 community hospitals in the United Kingdom, there is little published research on the quality of service provided by these hospitals. AIM: To compare the quality of terminal cancer care in community hospitals with a hospice as assessed by patients' closest lay carer (relative or friend). METHOD: Structured interview (or questionnaire based on the interview proforma) with closest lay carers of all patients dying over one year in 12 community hospitals in east Devon and a purpose-built hospice in the city of Exeter. RESULTS: A total of 292 cases (176 in community hospitals and 116 in a hospice) were identified, resulting in 238 carers being eligible for interview or questionnaire survey. Overall, 106 successful interviews and 55 questionnaires were completed, giving a response rate of 67.6%. Carers gave a near unanimous vote of excellence for the total care given by the hospice, while around 40% of carers of patients in community hospitals considered that improvements were possible. Community hospitals attracted more negative comments than hospices, with criticism being directed at problems of communication, lack of nursing staff, and lack of support in bereavement. Carers of hospice patients were significantly more likely to be present at the time of death than those of community hospital patients [45/70 (64%) vs. 31/89 (35%); chi 2 = 13.6, P < 0.001], an observation possibly because nursing staff in community hospitals are less experienced at dealing with terminally ill patients and such hospitals have fewer adequate facilities. CONCLUSIONS: Lay carers indicated great satisfaction with care given in the hospice and less satisfaction with care given in the community hospitals. However, the community hospitals are non-specialist units with far lower levels of trained staff. Improvements in terms of the communication skills of doctors and nurses, specific training for nurses in palliative care, and structured bereavement care could be made without necessarily increasing staffing numbers.

Attitude to Health↗
PubMed1997

Maintenance nortriptyline effects on electroencephalographic sleep in elderly patients with recurrent major depression: double-blind, placebo- and plasma-level-controlled evaluation.

Our aim was to contrast the effects of maintenance nortriptyline and placebo on electroencephalographic sleep measures in elderly recurrent depressives who survived 1-year without recurrence of depression. Patients on nortriptyline took longer to fall asleep and did not maintain sleep better than patients on placebo; however, maintenance nortriptyline was associated with more delta-wave production and higher delta-wave density in the first non-REM (NREM) period relative to the second. Nortriptyline levels were positively but weakly related to all-night delta-wave production during maintenance (accounting for 6.6% of the variance in delta-wave counts). Total phasic REM activity increased 100% under chronic nortriptyline relative to placebo, with a robust increase in the rate of REM activity generation across the night. Effective long-term pharmacotherapy of recurrent major depression is associated with enhancement in the rate of delta-wave production in the first NREM period (i.e., delta sleep ratio) and of REM activity throughout the night.

Aged↗
PubMed1997

Pacifastin, a novel 155-kDa heterodimeric proteinase inhibitor containing a unique transferrin chain.

A 155-kDa proteinase inhibitor, pacifastin, from plasma of the freshwater crayfish, Pacifastacus leniusculus, was found to be composed of two covalently linked subunits. The two subunits are encoded by two different mRNAs, which were cloned and sequenced. The heavy chain of pacifastin (105 kDa) is related to transferrins, containing three transferrin lobes, two of which seem to be active for iron binding. The light chain of pacifastin (44 kDa) is the inhibitory subunit, and has nine cysteine-rich inhibitory domains that are homologous to each other and to low molecular weight proteinase inhibitors isolated from the grasshopper, Locusta migratoria. The nine light chain domains and the Locusta inhibitors share a characteristic cysteine array (Cys-Xaa9-12-Cys-Xaa2-Cys-Xaa-Cys-Xaa6-8-Cys-Xaa4++ +-Cys) distinct from any described proteinase inhibitor family, suggesting that they constitute a new family of proteinase inhibitors. Pacifastin is the first known protein that has combined properties of a transferrin-like molecule and a proteinase inhibitor.

Amino Acid Sequence↗
PubMed1997

Corticosteroids inhibit lymphocyte binding to endothelium and intercellular adhesion: an additional mechanism for their anti-inflammatory and immunosuppressive effect.

Glucocorticosteroids (GCS) are potent anti-inflammatory and immunosuppressive agents widely used in the treatment of many medical conditions, but their mechanism of action is not yet fully understood. Some of the anti-inflammatory effects of GCS have been attributed to the synthesis of lipocortins, whereas the immunosuppressive effects are thought to be mediated through the inhibition of several immune functions through a down-regulation of cytokine gene expression. Another important mechanism of action of GCS may relate to their ability to interfere with the phenomena of adhesion and migration of inflammatory cells. In this study, the direct effects of GCS on lymphocyte adhesion capacity in vitro were investigated. We demonstrate that GCS inhibit lymphocyte adhesion to endothelium through the down-modulation of lymphocyte adhesion molecules. We also provide evidence that GCS inhibit cell aggregate formation induced by TCR ligation, which directly correlates with the down-modulation of LFA-1 and CD2, but not LFA-3 or ICAM-1. Such down-modulation was paralleled by a decrease in the steady state mRNA level of LFA-1 and CD2 gene products, which suggests a direct GCS control of the expression of these genes. Finally, we show that GCS effects are mediated through the GCS receptor, since they can be completely reversed by the GCS-R antagonist RU-486. This study supports the concept that some of the immunosuppressive and anti-inflammatory effects of GCS are likely to be exerted by the inhibition of adhesion-dependent lymphocyte functions.

Adrenal Cortex Hormones↗
PubMed1997

Sleep in the wake of complicated grief symptoms: an exploratory study.

Our aim was to explore the concept that the symptoms of complicated grief may be a form of posttraumatic distress, rather than depression, and thus may have different effects on sleep. Sixty-five recently bereaved elders with varying levels of symptoms of complicated grief and depression were stratified by high versus low levels of symptoms; a two-way analysis of variance examined main effects of level of complicated grief symptoms and depressive symptoms on selected sleep measures, as well as interactions. Complicated grief symptoms were independently associated with mild subjective sleep impairment but showed no main effects on electroencephalographic (EEG) sleep measures. In a multiple regression analysis, complicated grief symptoms interacted with depressive symptoms to increase REM sleep percent. Thus, it appears that complicated grief symptoms do not entail the changes of EEG sleep physiology seen in depression, with the possible exception of an interaction with coexisting depression to enhance REM sleep percent.

Aged↗
PubMed1997

Cdk2-dependent phosphorylation of Id2 modulates activity of E2A-related transcription factors.

The helix-loop-helix (HLH) protein Id2 is thought to affect the balance between cell growth and differentiation by negatively regulating the function of basic-helix-loop-helix (bHLH) transcription factors. Id2 acts by forming heterodimers that are unable to bind to specific (E-box) DNA sequences. Here we show that this activity can be overcome by phosphorylation of a serine residue within a consensus target site for cyclin-dependent kinases (Cdks). In vitro, Id2 can be phosphorylated by either cyclin E-Cdk2 or cyclin A-Cdk2 but not by cyclin D-dependent kinases. Analogous phosphorylation occurs in serum-stimulated human diploid fibroblasts at a time in late G1 consistent with the appearance of active cyclin E-Cdk2. The phosphorylation of Id2 in these cells correlates with the restoration of a distinct E-box-dependent DNA-binding complex, suggesting that the levels of this complex are modulated by both the abundance and phosphorylation status of Id2. These data provide a link between cyclin-dependent kinases and bHLH transcription factors that may be critical for the regulation of cell proliferation and differentiation.

3T3 Cells↗
PubMed1997

Safety of oral terbinafine: results of a postmarketing surveillance study in 25,884 patients.

OBJECTIVE: To broaden the safety database for oral terbinafine by determining the incidence of adverse events, particularly rare risks, that accompany its uncontrolled use in actual clinical practice. DESIGN: Four open, prospective, uncontrolled, postmarketing surveillance studies were conducted in unselected patients in 4 countries. No exclusion criteria were applied. The only treatment instructions participating physicians received were the manufacturer's product information. Physicians monitored patients for adverse events at baseline, during treatment, and at the end of treatment. Serious events were identified according to study protocol, which was consistent for all 4 studies, allowing data to be pooled and analyzed collectively. SETTING: Patients were recruited from dermatology, general, and family practices in the United Kingdom, the Netherlands, Germany, and Austria. PATIENTS: Of the 25884 patients who entered the study, 38.6% had concomitant diseases, 42.8% were taking other medications, and 22.7% were older than 60 years. The predominant indication for terbinafine treatment was onychomycosis (72.2%). INTERVENTIONS: Data on treatment duration was available for 25091 patients. Median duration of treatment was 12 weeks (mean, 13.2 weeks). Treatment extended beyond 6 weeks in 76.0% of patients and for at least 12 weeks in 59.3%. MAIN OUTCOME MEASURES: The incidence of adverse events as reported by physicians, with their opinions regarding relationship to terbinafine therapy. RESULTS: The incidence of adverse events was 10.5%; the majority involved the gastrointestinal system (4.9%) or skin (2.3%). These tended to be mild, transient, and reversible. Terbinafine was considered a possible or probable cause of 11 (0.04%) serious adverse events. No drug interactions were reported, even in patients taking oral antidiabetic agents, astemizole, terfenadine, or cimetidine hydrochloride. CONCLUSIONS: The positive safety profile established during controlled clinical trials of oral terbinafine extends to its uncontrolled use in clinical practice. No previously unrecognized risks were identified.

Adolescent↗
PubMed1997

Temporal profiles of the course of depression during treatment. Predictors of pathways toward recovery in the elderly.

BACKGROUND: Predictors of treatment response and recovery from depression in late life remain poorly understood. Previous studies have focused on a narrow range of response and recovery variables; namely, whether patients achieve or do not achieve a defined outcome or time to achieve the outcome. Whether patients vary in their pathways toward those outcomes--and the extent to which such variation can be anticipated by patient characteristics prior to treatment--has not been empirically examined. METHODS: Depression symptom levels were monitored for 18 weeks in 95 persons aged 60 years or older who were experiencing a recurrence of major depression. Subjects received standardized combined nortriptyline treatment and interpersonal psychotherapy throughout the period. Cluster analysis was used to identify depression recovery patterns. Multivariate analyses considered whether recovery patterns were predicted by pretreatment psychosocial, clinical, and electroencephalographic sleep characteristics. RESULTS: Four subgroups of elders were identified who differed in rate, stability, and direction of recovery, ie, those showing (1) rapid sustained improvement, (2) delayed but sustained improvement, (3) partial or mixed response, or (4) no response. Pretreatment characteristics reliably predicted subjects' group membership. Higher levels of acute and chronic stressors, poorer social supports, younger age at first depressive episode, endogenous depression, higher current anxiety, older current age, and poorer subjective and objective (electroencephalographic) sleep predicted poorer response profiles. CONCLUSIONS: There are multiple pathways by which individuals begin to emerge from depression; these pathways can be identified empirically. Variables from diverse psychobiologic domains can be used to predict which persons are likely to advance along which trajectories toward recovery.

Age Factors↗
PubMed1997

Genetic patterning of the developing mouse tail at the time of posterior neuropore closure.

Posterior neuropore (PNP) closure coincides with the end of gastrulation, marking the end of primary neurulation and primary body axis formation. Secondary neurulation and axis formation involve differentiation of the tail bud mesenchyme. Genetic control of the primary-secondary transition is not understood. We report a detailed analysis of gene expression in the caudal region of day 10 mouse embryos during primary neuropore closure. Embryos were collected at the 27-32 somite stage, fixed, processed for whole mount in situ hybridisation, and subsequently sectioned for a more detailed analysis. Genes selected for study include those involved in the key events of gastrulation and neurulation at earlier stages and more cranial levels. Patterns of expression within the tail bud, neural plate, recently closed neural tube, notochord, hindgut, mesoderm, and surface ectoderm are illustrated and described. Specifically, we report continuity of expression of the genes Wnt5a, Wnt5b, Evx1, Fgf8, RARgamma, Brachyury, and Hoxb1 from primitive streak and node into subpopulations of the tail bud and caudal axial structures. Within the caudal notochord, developing floorplate, and hindgut, HNF3alpha, HNF3beta, Shh, and Brachyury expression domains correlate directly with known genetic roles and predicted tissue interdependence during induction and differentiation of these structures. The patterns of expression of Wnt5a, Hoxb1, Brachyury, RARgamma, and Evx1, together with observations on proliferation, reveal that the caudal mesoderm is organised at a molecular level into distinct domains delineated by longitudinal and transverse borders before histological differentiation. Expression of Wnt5a in the ventral ectodermal ridge supports previous evidence that this structure is involved in epithelial-mesenchymal interaction. These results provide a foundation for understanding the mechanisms facilitating transition from primary to secondary body axis formation, as well as the factors involved in defective spinal neurulation.

Animals↗
PubMed1997

cDNA cloning and pattern of expression of an adult, female-specific chymotrypsin from Aedes aegypti midgut.

A cDNA for a midgut chymotrypsin, induced by a blood meal, has been cloned and sequenced from the mosquito Aedes aegypti. The 938 base sequence codes for a 268 amino acid protein, which contains an 18-residue signal peptide and a seven-residue activation peptide. The deduced amino acid sequence contains several features typical of chymotrypsin proteases, including the catalytic triad of serine proteases and the residues that determine the chymotrypsin substrate specificity pocket. The chymotrypsin mRNA, absent in larvae, pupae, males and newly emerged females, reaches detectable levels within 24 h post-emergence and attains a maximum level 3-7 days after emergence. Translation of the chymotrypsin mRNA is induced by feeding a protein meal, and there is a dramatic increase in midgut chymotrypsin enzymatic activity after feeding. Chymotrypsin activity remained high during protein digestion, but chymotrypsin protein levels and enzymatic activity were almost undetectable once digestion was completed, 48 h after feeding.

Aedes↗
PubMed1997

Catamenial variations in erythrocyte sodium-lithium countertransport and blood pressure.

1. We undertook a temporal study of external sodium-stimulated lithium efflux (sodium-lithium countertransport) in erythrocytes and blood pressure by measuring these two parameters in three phases of the menstrual cycle (menstrual, midcycle and luteal phases) in 22 healthy, non-medicated females with regular menstrual cycles. Plasma oestradiol and progesterone levels were also determined. 2. Sodium-lithium countertransport activity (activity in 140 mmol/l external NaCl) in the midcycle phase (0.176 +/- 0.017 mmol h-1 l-1 of cells) was lower than in the menstrual (0.192 +/- 0.016 mmol h-1 l-1 of cells, P < 0.030) and luteal (0.203 +/- 0.018 mmol h-1 l-1 of cells, P < 0.030) phases. The Vmax of the transporter changed similarly but the K(m) was unaltered. 3. The plasma oestradiol level was 628.9 +/- 39.1 pmol/l in the midcycle phase, higher than in the menstrual (232 +/- 18.5 pmol/l, P < 0.001) and luteal (372.5 +/- 28.1 pmol/l, P < 0.001) phases. The progesterone level was 28.6 +/- 2.1 nmol/l in the luteal phase, and values were lower in the menstrual (2.5 +/- 0.3 nmol/l, P < 0.001) and midcycle (2.8 +/- 0.4 nmol/l, P < 0.001) phases. 4. There was no correlation between plasma oestradiol and sodium-lithium countertransport activity or Vmax during the menstrual cycle, but plasma progesterone was positively correlated with sodium-lithium countertransport activity (r = 0.478, P < 0.025, n = 22) and Vmax (r = 0.551, P < 0.045, n = 14) in the luteal phase. 5. Systolic blood pressure did not change significantly during the menstrual cycle. However, the diastolic pressure showed variation similar to that in sodium-lithium countertransport activity/Vmax, its midcycle value of 66.6 +/- 1.4 mmHg being lower than that in the luteal (71.6 +/- 1.3 mmHg, P < 0.025) and menstrual (70.6 +/- 1.4 mmHg, P < 0.025) phases. 6. We conclude that sodium-lithium countertransport activity exhibits catamenial variation. Therefore we suggest, given this observation, that blood sampling for the assessment of the state of activity of the transport system be standardized in relation to a phase of the menstrual cycle in future studies involving females.

Adult↗
PubMed1997

Animal serum-free culture of purified human CD34+ cells: amplification of progenitors from G-CSF and GM-CSF-mobilized peripheral blood.

The isolation and culture of human CD34+ cells could have broad clinical application for hematologic support following high-dose chemotherapy or bone marrow transplantation. The need for reproducible, animal product-free conditions for the culture of progenitors is crucial to the widespread clinical implementation of ex vivo cell therapies. In these studies, we explored the use of animal serum-free (ASF) medium for the culture of isolated human bone marrow and peripheral blood CD34+ cells. In this ASF system, isolated CD34+ cells were cultured using a variety of different growth factor combinations. Such ASF culture conditions yielded equivalent to superior cell and progenitor growth when directly compared with culture containing 10% fetal calf serum (FCS). In cultures containing IL-1, IL-3, and stem cell factor, total cell numbers increased, on average, 33-fold over the first 2 weeks. On phenotypic analysis, the ASF cultures demonstrated sustained proliferation of CD33+ myeloid cells throughout the culture period. CD34+ cell numbers increased during the first 7-10 days of culture, with a mean 3.4-fold expansion. Concomitant with the CD34+ cell expansion was an average 8.2-fold expansion of colony-forming unit-granulocyte-macrophage (CFU-GM) and a 102.0-fold increase in burst-forming units-erythrocytes (BFU-E). Likewise, a mean 4929-fold expansion of CD41a+ megakaryocyte progenitors was observed in these CD34+ cultures. Different combinations of growth factors affected the fold increase in cell and progenitor number. When CD34+ cell cultures from normal healthy volunteers mobilized with either G-CSF or GM-CSF were compared, similar expansions of total cell and progenitor cells resulted. However, CD41+ cells expansions were greater in those samples from G-CSF-mobilized volunteers in every case tested. These studies established the feasibility of this ASF CD34+ cell culture system to generate a population of maturing progenitors for potential use in transfusion support during cytopenic periods following high-dose chemotherapy or bone marrow transplantation.

Animals↗