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Biomedical subjects

A Hudson

Publications and source records attributed to A Hudson.

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

Ultrabithorax regulates genes at several levels of the wing-patterning hierarchy to shape the development of the Drosophila haltere.

Arthropods and vertebrates are constructed of many serially homologous structures whose individual patterns are regulated by Hox genes. The Hox-regulated target genes and developmental pathways that determine the morphological differences between any homologous structures are not known. The differentiation of the Drosophila haltere from the wing through the action of the Ultrabithorax (Ubx) gene is a classic example of Hox regulation of serial homology, although no Ubx-regulated genes in the haltere have been identified previously. Here, we show that Ubx represses the expression of the Wingless (Wg) signaling protein and a subset of Wg- and Decapentaplegic-activated genes such as spalt-related, vestigial, Serum Response Factor, and achaete-scute, whose products regulate morphological features that differ between the wing and haltere. In addition, we found that some genes in the same developmental pathway are independently regulated by Ubx. Our results suggest that Ubx, and Hox genes in general, independently and selectively regulate genes that act at many levels of regulatory hierarchies to shape the differential development of serially homologous structures.

Animals↗
PubMed1998

Early events in leaf development.

Morphological studies of early events in leaf development have been hindered by the lack of stereotypic patterns of cell division and markers for cell identity. However, molecular genetic analysis, particularly in maize, has begun to suggest the mechanisms which partition meristematic cells into a leaf primordium, define regional identities within the primordium and direct localised growth which leads to outgrowth and flattening of the leaf. Therefore, the leaf may provide a model for pattern formation applicable to other parts of the plant.

Meristem↗
PubMed1997

Synaptojanin 1: localization on coated endocytic intermediates in nerve terminals and interaction of its 170 kDa isoform with Eps15.

Synaptojanin 1 is an inositol 5-phosphatase with a putative role in clathrin-mediated endocytosis. Goal of this study was to provide new evidence for this hypothesis. We show that synaptojanin 1 is concentrated at clathrin-coated endocytic intermediates in nerve terminals. Furthermore, we report that synaptojanin-170, an alternatively spliced isoform of synaptojanin 1, binds Eps15, a clathrin coat-associated protein. Binding is mediated by the COOH-terminal region of synaptojanin-170 which we show here to be poorly conserved from rat to humans, but to contain in both species three asparagine-proline-phenylalanine (NPF) repeats. This motif has been found to be the core of the binding site for the EH domains of Eps15. Together with previous data, our results suggest that synaptojanin 1 can be recruited to clathrin-coated pits via a multiplicity of interactions.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Plant meristems: cell signalling keeps the balance.

Genetic and molecular analysis in Arabidopsis has identified components of a putative cell signalling pathway that appears to regulate the balance between stem cell proliferation and fate specification in meristems.

Animals↗
PubMed1995

Sex differences in the distribution of EEG frequencies during sleep: unipolar depressed outpatients.

Sex differences in period-amplitude-analysed (PAA) sleep EEG activity were evaluated in 20 symptomatic, unmedicated, unipolar, depressed outpatients. 19/20 PAA measures showed significant gender main effects or interactions. Overall, depressed females showed a higher incidence and amplitude of fast frequency, beta activity than males, particularly in the right hemisphere. Moreover, gender effects were also evident in sleep-stage-independent analysis of PAA measures. These findings are in striking contrast to normal controls for whom only slow-frequency activity differentiates males from females. These findings suggest that sex differences are stronger in depressed patients than those observed in normals and that these effects are more pronounced than age-related changes in sleep EEG activity.

Adult↗
PubMed1995

Alteration of Chlamydia trachomatis biologic behavior in synovial membranes. Suppression of surface antigen production in reactive arthritis and Reiter's syndrome.

OBJECTIVE: To investigate the biologic state of Chlamydia and its surface antigen expression in the synovial membranes of patients with Chlamydia-associated reactive arthritis/Reiter's syndrome (ReA/RS). METHODS: Expression of chlamydial lipopolysaccharide (LPS), major outer membrane protein (MOMP), and elementary body (EB) antigens was studied by gold labeling immunoelectron microscopy on 6 synovial membrane and 2 synovial fluid (SF) pellet samples from 6 patients with Chlamydia-associated arthritis. The study findings were compared with 24-hour cultures of HeLa cells infected with Chlamydia trachomatis EB. RESULTS: Persistent C trachomatis infection was found in all 6 synovial membrane samples from patients who had either early or chronic arthritis. The infection persisted despite antibiotic treatment, including a 1-month course of doxycycline therapy. Most persistent organisms were atypical reticulate bodies (RBs) found in both fibroblasts and macrophages. Specific, but weak, immunogold staining for all 3 antibodies was found on both intracellular RBs and extracellular EBs. In the SF samples, Chlamydia surface antigens were detected only in phagosomes containing degraded electron-dense materials. CONCLUSION: The synovial membrane biopsies conducted in this study of Chlamydia-associated ReA/RS revealed atypical RBs with diminished MOMP and LPS expression. Such altered organisms may escape immune surveillance and contribute to disease chronicity; moreover, these organisms may be difficult to detect and treat in some ReA/RS patients.

Adult↗
PubMed1995

Meeting patients' needs: quality care in a changing environment.

Recent surveys of patients in New York and Cleveland, among other cities, indicate that there is substantial room for improvement in meeting patients' needs and preferences, particularly in the areas of emotional support, coordination of care, discharge preparation, and the involvement of family and friends. Hospitals are using a variety of techniques to improve patient care and organizational efficiency in this challenging environment. One prominent approach, reengineering, offers a means by which hospitals can integrate highly specialized departmental structures and functions by focusing on interdisciplinary teamwork and organizing the delivery of care around patients. Key elements of successful hospital reengineering efforts have included: - the involvement and commitment of senior management and other key stakeholders, particularly physicians, nurses, and union representatives; - investment in staff training and retraining, and the redesign of staff evaluation and compensation systems; - timely, unit-specific measures of patient satisfaction and the clinical quality of care; - consistent and frequent internal communication between staff and leadership; and - treatment that emphasizes communication among caregivers, patients, and their family members. Several basic issues need to be addressed if hospitals are to offer technically sophisticated medical care that is also responsive to their patients' personal needs, including: - variations among patients regarding the amount of information they want and need, and the amount of involvement they want in their care; - the means by which patients will get information about their medical care, and who will provide any additional support that may be needed by non-English-speaking or socioeconomically disadvantaged patients; and - the specific changes in medical practice and hospital processes that will promote the involvement of patients in their care.

Chicago↗
PubMed1995

Genetic and cellular characteristics of bladder outlet obstruction.

Urinary bladder outlet obstruction is a common medical problem. In order to understand the effects of outlet obstruction on bladder morphology, physiology, and pharmacology, several animal models of obstruction have been developed using a variety of species. Although there are marked differences in bladder size, capacity, compliance, physiology, and pharmacology among these species, responses to outlet obstruction have many common characteristics. This article will be separated into six areas: introduction, genetic factors mediating the response during the initial period of partial outlet obstruction and overdistension, cytostructural alterations that accompany compensated bladder function, alterations in innervation accompanying bladder hypertrophy secondary to partial outlet obstruction, alterations in calcium translocation during bladder hypertrophy, and metabolic factors involved in the response to partial outlet obstruction.

Animals↗
PubMed1995

Inhibition of amine oxidase activity by derivatives that recognize imidazoline I2 sites.

Nonadrenergic imidazoline binding sites (imidazoline I2 sites) have been described to be colocated with monoamine oxidase (MAO) in the mitochondrial fraction of various cell types. In the present work, the authors considered whether this colocation could be associated with a functional interplay. In rat liver membranes, [3H]-idazoxan binding to I2 receptors was competed for by naphazoline and idazoxan, which also shared a high affinity for alpha-2 adrenoceptors (alpha-2 ARs). The chemicals 2-n-heptylimidazoline (S 15430), 1-methyl-5-n-heptylimidazole (S 15674), 2-benzofuran-2-yl-imidazoline (RX 801077) and 2-(1,3-benzodioxanyl)-2-imidazoline (RX 821029) exhibited higher affinity for I2 receptors than for alpha-2 ARs. The most selective agent was S 15430 with a 150-fold higher affinity for liver I2 receptors than for adipocyte alpha-2 ARs. Moreover, [3H]-idazoxan binding was also competed for by several MAO inhibitors (MAOI) that are not imidazoline or guanidinium derivatives such as tranylcypromine, harmaline, clorgiline and pargyline. Rat liver MAO activity was not only inhibited by MAOIs but also by some imidazoline derivatives: cirazoline, naphazoline, S 15674, RX 801077 and RX 821029. Idazoxan had no effect on MAO activity; it neither inhibited MAO nor prevented the inhibition induced by other imidazolines or MAOIs. This suggested that the ligand recognition site of I2 receptors was distinct from the MAOI target site. Furthermore, some imidazolines inhibited the activity of bovine plasma amine oxidase, an enzyme that does not possess the same cofactor as MAO and is insensitive to harmaline or pargyline.(ABSTRACT TRUNCATED AT 250 WORDS)

Amine Oxidase (Copper-Containing)↗
PubMed1994

Brisk walking and serum lipid and lipoprotein variables in previously sedentary women--effect of 12 weeks of regular brisk walking followed by 12 weeks of detraining.

The purpose of this study was to examine the effectiveness of brisk walking as a means of improving endurance fitness and influencing serum lipid and lipoprotein variables in previously sedentary women. Walkers (n = 10, mean (s.e.m.) age 47.3(2.0) years) followed a programme of brisk walking (mean(s.e.m.) speed 1.76(0.03) m s-1) for 12 weeks, after which the training stimulus was withdrawn. Controls (n = 10, mean(s.e.m.) age 41.6(1.2) years) maintained their habitual sedentary lifestyle throughout. Endurance fitness was determined using laboratory measures of responses to treadmill walking. Serum lipid and lipoprotein variables were determined in venous blood (12-h fasted). Body fatness was assessed by anthropometry and dietary practice using the 7-day weighed food intake technique. Measurements were repeated after 12 and 24 weeks. Brisk walking resulted in a decrease in heart rate and blood lactate concentration during exercise, while detraining was accompanied by a reversal of these changes. Changes in body mass and the ratio of circumferences at the waist and hip did not differ between groups but the sum of four skinfolds decreased with brisk walking and increased with detraining. High density lipoprotein (HDL) and HDL2 cholesterol increased with walking and decreased with detraining but no between group changes (analysis of variance, P < 0.05) were found in other lipid and lipoprotein variables. These findings suggest that regular brisk walking can improve endurance fitness and increase HDL cholesterol concentration in sedentary women.

Adipose Tissue↗
PubMed1994

Community psychiatric nurse teams: intensive support versus generic care.

BACKGROUND: This study evaluated whether a community psychiatric nurse (CPN) team providing a comprehensive aftercare service, using a case management approach, improves psychopathology and social functioning of the long-term mentally ill, and reduces hospital use compared with a generic CPN team. METHOD: Patients suffering from severe and persistent mental health problems were randomised to intensive aftercare or generic care after referral to the CPN manager. Each group contained 41 patients who were assessed at baseline and at 6, 12 and 18 months by an independent research psychologist. Outcome measures included the GAS, PSE, SAS, patient and relatives' satisfaction, number of admissions, and length of stay. RESULTS: No difference between the groups was found on any of the outcome measures, despite the much higher number of contacts of the intensive (n = 52) versus generic CPNs (n = 13) and the much greater range of interventions. CONCLUSIONS: Intensive aftercare for people with persistent mental health problems was not found to be of greater benefit than generic CPN care. Many factors need to be considered for aftercare to be effective, including community resources, process of care, and staff training.

Activities of Daily Living↗
PubMed1993

Olive: a key gene required for chlorophyll biosynthesis in Antirrhinum majus.

Olive (oli) is a recessive nuclear mutation of Antirrhinum majus which reduces the level of chlorophyll pigmentation and affects the ultrastructure of chloroplasts. The oli-605 allele carries a Tam3 transposon insertion which has allowed the locus to be isolated. The oli gene encodes a large putative protein of 153 kDa which shows homology to the products of two bacterial genes necessary for tetrapyrrole-metal chelation during the synthesis of bacteriochlorophyll or cobyrinic acid. We therefore propose that the product of the oli gene is necessary for a key step of chlorophyll synthesis: the chelation of magnesium by protoporphyrin IX. Somatic reversion of the oli-605 allele produces chimeric plants which indicate that the oli gene functions cell-autonomously. Expression of oli is restricted to photosynthetic cells and repressed by light, suggesting that it may be involved in regulating the rate of chlorophyll synthesis in green tissues.

Amino Acid Sequence↗