Biomedical subjects

K Patel

Publications and source records attributed to K Patel.

At least 73 records · Page 4Linked to original sources

PubMed2001

Down and out in America: children and health care.

One of the worst forms of inequality in the health care field is the inequality suffered by children. In 1996, over 14.5 million children lived in poverty in the United States. Children who live in poverty are less likely to have health insurance and have less access to health care and thus are more likely to suffer negative outcomes in health care. The Congress of the United States in 1997 enacted the State Children's Health Insurance Program (S-CHIP) to expand health insurance coverage for children. This paper examines the major features of the program, actions undertaken by the state governments under this program to expand health insurance coverage for children, and provides some preliminary analysis of the potential positive and negative impact of the program.

Adolescent↗

PubMed2001

Peginterferon alpha-2b: a new approach to improving response in hepatitis C patients.

Chronic hepatitis C infection affects approximately four million Americans. Over the last decade, Type 1 interferons (IFNs) have been the mainstay of therapy for suitable patients. Recently, the combination of IFN plus ribavirin, with enhanced response rates, has replaced IFN monotherapy for treatment of these patients. The addition of a polyethylene glycol (peg) moiety to IFN alpha-2b has provided a drug with reduced clearance whilst retaining biological and antiviral activity. This formulation allows once-weekly dosing and enhances sustained response rates, without significantly changing the safety and tolerability of IFN. Clinical trials indicate a doubling of sustained virological response rates for regimens utilising pegIFN alpha-2b, compared with standard IFN-alpha 2b. The combination of pegIFN alpha-2b and ribavirin further increases the sustained virological response rates to > 50% for suitable patients. Future pegIFN alpha-2b studies will need to examine drug profiles in patients with co-morbid conditions (e.g., renal impairment, liver transplantation), as well as safety and efficacy issues in different ethnic groups. Further clinical trials are also required to determine the benefits of pegIFN alpha-2b in previous non-responders or relapse patients and as maintenance therapy to prevent disease progression. Finally, careful cost effectiveness analyses will need to be performed.

Animals↗

PubMed2001

Insulin-like growth factor axis during embryonic development.

The insulin-like growth factor (IGF) axis has been studied extensively in the developing vertebrate embryo. Knockout experiments have demonstrated that both IGF-I and -II are required for normal development in the mouse embryo, and mRNA and protein expression patterns for both growth factors, together with those for the type I IGF receptor and the six IGF-binding proteins, have been analysed in embryos from different species. Although the unique temporal and spatial expression patterns of these genes indicates important roles for the IGF axis during organ and whole animal development, the variation and complexity of expression makes these roles difficult to unravel. However, one possible mechanism unifying the IGF system in development is programmed cell death (apoptosis), which has been shown to be important in sculpting embryonic tissues, and, in particular, the developing limb bud. In addition, the very early onset of expression of various IGF family members in chicken embryos further emphasizes the fundamental importance of this system in development. This article reviews the work that has been carried out in this area in the context of current understanding of the IGF system.

Animals↗

PubMed2000

Mental health. Facing hard truths.

A survey of 104 mental health units found that half did not have policies on treatment of detained patients from black and ethnic minority groups. Almost three-quarters had no policy for dealing with racial harassment of black and ethnic-minority patients. 11 percent of patients whose notes were examined had reported racial harassment.

Black or African American↗

PubMed2000

Differential anti-inflammatory effects of immunosuppressive drugs: cyclosporin, rapamycin and FK-506 on inducible nitric oxide synthase, nitric oxide, cyclooxygenase-2 and PGE2 production.

OBJECTIVE AND DESIGN: Cyclosporin, FK-506 and rapamycin have similar but distinct modes of interaction with cyclophilins, calcineurins and transcription factors. These immunosuppressive drugs have also been shown to inhibit cytotoxic and inflammatory responses in macrophage. Therefore, we evaluated the mechanism of action of these drugs on iNOS and COX-2 expression by macrophages, the products of which (NO and PGE2) have cytotoxic and proinflammatory activities. MATERIALS AND METHODS: The murine macrophage cell line RAW 264.7 was grown as monolayer cultures. The effects of pharmacologically relevant concentrations of cyclosporin, rapamycin and FK-506 were evaluated in the presence and absence of lipopolysaccharide (LPS) which is a known inducer of iNOS and COX-2. Subsequently the expression of iNOS and COX-2 were analyzed by Western and Northern analysis. The production of NO and PGE2 were assayed by Greiss and RIA respectively. RESULTS: Cyclosporin (1-5 microg/ml) and rapamycin (1.0-10 nM) but not FK-506 (5-10 nM) inhibited both iNOS and COX-2 expression at mRNA level which led to significant inhibition of NO and PGE2 production. CONCLUSION: These studies characterize differential mechanistic capacity of the immunophilin-binding immunosuppressive drugs (comparable to hydrocortisone) to inhibit both iNOS and COX-2 expression. Inhibition of iNOS and COX-2 mRNA accumulation by cyclosporin and rapamycin seem to be distinct. These studies also highlight potential anti-inflammatory properties of these drugs in addition to their known immunosuppressive activity.

Animals↗

PubMed2000

Altered expression of insulin-like growth factor-1 and insulin like growth factor binding proteins-2 and 5 in the mouse mutant Hypodactyly (Hd) correlates with sites of apoptotic activity.

Insulin-like growth factor-I (IGF-I) mediated signalling has been implicated to be of significant importance during vertebrate embryonic development. IGF-I signalling has also been shown to be modulated by a number of IGF binding proteins that are thought to act as either agonists or antagonists of IGF activity. IGF-I has been implicated in a number of cellular processes, including cell division and programmed cell death (apoptosis). We have used the mouse mutant Hypodactyly (Hd) as a tool to determine the role of IGF-I and two key IGF binding proteins (IGFBP-2 and IGFBP-5) during embryonic development. The Hd mutant is a good model with which to study developmental cascades, since it has a distinct phenotype in the limb where cellular and molecular circuits have been thoroughly investigated. The distinctive pointed limb buds observed in Hd mutant embryos have been shown to be the result of a massive increase in apoptosis. We show that all three genes, IGF-1, IGFBP-2 and IGFBP-5, display restricted expression patterns during limb development. Indeed, IGFBP-5 shows a remarkable similarity to the expression of Engrailed-1, which is the vertebrate homologue of the Drosophila selector gene Engrailed. We show that there is downregulation in the expression of IGFBP-2 in the entire apical ectodermal ridge (AER) in homozygous Hd/Hd limb buds, whereas IGFBP-5 is downregulated in specific regions in the mutant AER. IGF-I expression is downregulated in Hd limb buds in regions undergoing high levels of cell death, consistent with its proposed role as an anti-apoptotic factor, while IGFBP-5 is found at higher levels in regions of cell death, consistent with reports of its association with apoptosis in adult tissues. We propose that these three components of the IGF axis could be involved in the manifestation of the mutant phenotype in Hypodactyly, and that this is probably a result of their ability to regulate cell survival and cell death.

Animals↗

PubMed2000

Contribution of single somites to the skeleton and muscles of the occipital and cervical regions in avian embryos.

Controversy has surrounded the process of resegmentation of cervico-occipital somites. We have reinvestigated this topic by grafting single somites of quail embryos homotopically into chick embryos. Somites one to five contribute to the skull. Somites one and two contribute to the parasphenoid, which develops by direct ossification in a non-segmental fashion. All cartilaginous derivatives of the somites are segmental. Somite two forms a stripe of cells in the basioccipital, exoccipital and supraoccipital. Somites three to five give rise to the subsequent caudal parts of the basioccipital and exoccipital. Somite five forms the first motion segment including the occipital condyle, the cranial part of the atlas and the tip of the dens axis. Therefore, the border between head and neck is in the centre of somite five, and corresponds to the expression boundary of Choxb-3. Somite six forms the caudal part of the atlas and the cranial part of the axis. Somites two to eight all contribute to the cranio-cervical muscles with the exception of the Mm. rectus capitis dorsalis and ventralis and the M. biventer cervicis, which do not receive contributions from somite two. In contrast, the M. cucullaris capitis is exclusively formed by myogenic cells from somite two, which parallels its exclusive innervation by the accessory nerve. Our data confirm the segmental nature of the occiput, and show that resegmentation is a very regular process involving all except the four cranialmost somites. Except for somites one and two, all of the somites contribute to the muscles located at the appropriate levels.

Animals↗

PubMed2000

Convergence between CD98 and integrin-mediated T-lymphocyte co-stimulation.

CD98 is a widely expressed cell surface heterodimeric glycoprotein, which is rapidly up-regulated upon activation of T lymphocytes. Monoclonal antibody (mAb) 80A10 recognizes an epitope on CD98 and in combination with CD3 antibody causes proliferation of peripheral blood T lymphocytes. CD98 co-stimulatory activity, mediated by either mAb 80A10 or 4F2, a well-characterized CD98-specific mAb, is blocked in the presence of the soluble beta1 integrin antibody 18D3. Previously we have reported that co-stimulatory activity of antibodies to integrins alpha4beta1, alpha5beta1, alphaLbeta2 and alpha4beta7 is inhibited by 18D3, whereas co-stimulation mediated by non-integrins was unaffected. Thus the non-integrin CD98 is uniquely sensitive to the inhibitory effects of beta1 integrin-blocking antibodies, which may reflect convergent signalling mechanisms between integrins and CD98. This is consistent with recent reports suggesting that CD98 may regulate integrin-mediated adhesive events.

Antibodies, Monoclonal↗

PubMed2000

Comparison of rizatriptan 10 mg vs. zolmitriptan 2.5 mg in the acute treatment of migraine. Rizatriptan-Zolmitriptan Study Group.

The efficacy and tolerability of rizatriptan (MAXALT) and zolmitriptan (ZOMIG) were compared in a randomized, double-blind, double-dummy, stratified (on prior use of rizatriptan and/or zolmitriptan), placebo-controlled, single attack study in 766 patients. Rizatriptan tended to provide freedom from pain sooner than zolmitriptan (hazard ratio 1.26, P = 0.075), acting within 60 min following dosing. More patients were pain free at 2 h on rizatriptan than on zolmitriptan (43.2% vs. 35.6%, P=0.041), while headache relief at 2 h was similar (70.5% vs. 66.8%). At 2 h, fewer patients on rizatriptan had symptoms of photophobia (35.6% vs. 43.5%, P = 0.029) and nausea (25.2% vs. 32.5%, P=0.046), and more patients on rizatriptan had normal function (45.4% vs. 37.0%, P=0.025) than zolmitriptan. Headache recurred in 28% of patients taking rizatriptan, 29% taking zolmitriptan and 26% taking placebo. Both active treatments were effective compared to placebo and were well tolerated. The most common side-effects with rizatriptan were asthenia/fatigue, somnolence and dizziness, while the most common side-effects with zolmitriptan were asthenia/fatigue and dizziness.

Adult↗

PubMed2000

Albumin as an outcome measure in haemodialysis in patients: the effect of variation in assay method.

BACKGROUND: Serum/plasma albumin is an important predictor of future mortality/morbidity in haemodialysis (HD) patients and has been proposed as an important audit measure. Different methods of albumin assay give different results and the bias between methods may be greater in renal failure patients. METHODS: Albumin concentration in plasma was measured by three methods, two dye-binding methods (bromocresol green (BCG) and bromocresol purple (BCP)) and an immuno-turbidimetric (ITM) method, in 143 HD patients (group I) and 49 non-renal patients (group II). Comparisons were made between means, variation in differences across a range of albumin concentrations and on the percentage of patients within the normal range. RESULTS: In HD patients (group I), BCG over-estimated plasma albumin compared with the other two methods. The difference could be as much as 10 g/l and was more marked in hypoalbuminaemic patients. The BCP method gave results closer to the ITM method, particularly in HD patients. These differences were less marked in group II patients but both methods overestimated albumin compared with the ITM method. Using the BCG local laboratory normal range, 84% of HD patients had plasma albumin concentrations within the normal range but this fell to 57% if the BCP results were used. CONCLUSIONS: The method for determining albumin concentration has a marked effect on the results particularly in HD patients. BCG, the most commonly used method, gives higher results than other methods and correlates poorly with an immunological method. These differences make comparative audit between nephrology units difficult and have implications for other biochemical variables and other specialties.

Biomarkers↗

PubMed2000

Perioperative management of a common disorder: hereditary haemochromatosis.

Hereditary haemochromatosis is the commonest autosomal recessive disorder affecting Caucasian populations, and is readily diagnosed on the basis of elevated total body iron stores and genetic testing. Increased awareness of this disease in the community will hopefully prompt earlier testing and diagnosis. Treatment with regular phlebotomy is simple and effective and can prevent significant morbidity and mortality. Preoperative evaluation of patients with this disorder should consider the potential multisystem involvement in iron overload.

Journal Article↗

PubMed2000

Size distribution of recruited alveolar volumes in airway reopening.

In 11 isolated dog lung lobes, we studied the size distribution of recruited alveolar volumes that become available for gas exchange during inflation from the collapsed state. Three catheters were wedged into 2-mm-diameter airways at total lung capacity. Small-amplitude pseudorandom pressure oscillations between 1 and 47 Hz were led into the catheters, and the input impedances of the regions subtended by the catheters were continuously recorded using a wave tube technique during inflation from -5 cm H(2)O transpulmonary pressure to total lung capacity. The impedance data were fit with a model to obtain regional tissue elastance (Eti) as a function of inflation. First, Eti was high and decreased in discrete jumps as more groups of alveoli were recruited. By assuming that the number of opened alveoli is inversely proportional to Eti, we calculated from the jumps in Eti the distribution of the discrete increments in the number of opened alveoli. This distribution was in good agreement with model simulations in which airways open in cascade or avalanches. Implications for mechanical ventilation may be found in these results.

Animals↗

PubMed2000

Subnuclear trafficking of estrogen receptor-alpha and steroid receptor coactivator-1.

We have analyzed ligand-dependent, subnuclear movements of the estrogen receptor-alpha (ERalpha) in terms of both spatial distribution and solubility partitioning. Using a transcriptionally active green fluorescent protein-ERalpha chimera (GFP-ERalpha), we find that 17beta-estradiol (E2) changes the normally diffuse nucleoplasmic pattern of GFP-ERalpha to a hyperspeckled distribution within 10-20 min. A similar reorganization occurs with the partial antagonist 4-hydroxytamoxifen; only a subtle effect was observed with the pure antagonist ICI 182,780. To examine the influence of ligand upon ERalpha association with nuclear structure, MCF-7 cells were extracted to reveal the nuclear matrix (NM). Addition of E2, 4-hydroxytamoxifen, or ICI 182,780 causes ERalpha to partition with the NM-bound fraction on a similar time course (10-20 min) as the spatial reorganization suggesting that the two events are related. To determine the effects of E2 on the redistribution and solubility of GFP-ERalpha, individual cells were directly examined during both hormone addition and NM extraction and showed that GFP-ERalpha movement and NM association were coincident. Colocalization experiments were performed with antibodies to identify sites of transcription (RNA pol Ilo) and splicing domains (SRm160). Using E2 treated MCF-7 cells, minor overlap was observed with transcription sites and a small amount of the total ERalpha pool. Experiments performed with bioluminescent derivatives of ERalpha and steroid receptor coactivator-1 (SRC-1) demonstrated both proteins colocalize to the same NM-bound foci in response to E2 but not the antagonists tested. Deletion mutagenesis and in situ analyses indicate intranuclear colocalization requires a central SRC-1 domain containing LXXLL motifs. Collectively, our data suggest that ERalpha transcription function is dependent upon dynamic early events including intranuclear rearrangement, NM association, and SRC-1 interactions.

Antibodies, Monoclonal↗

PubMed2000

Dual origin and segmental organisation of the avian scapula.

Bones of the postcranial skeleton of higher vertebrates originate from either somitic mesoderm or somatopleural layer of the lateral plate mesoderm. Controversy surrounds the origin of the scapula, a major component of the shoulder girdle, with both somitic and lateral plate origins being proposed. Abnormal scapular development has been described in the naturally occurring undulated series of mouse mutants, which has implicated Pax1 in the formation of this bone. Here we addressed the development of the scapula, firstly, by analysing the relationship between Pax1 expression and chondrogenesis and, secondly, by determining the developmental origin of the scapula using chick quail chimeric analysis. We show the following. (1) The scapula develops in a rostral-to-caudal direction and overt chondrification is preceded by an accumulation of Pax1-expressing cells. (2) The scapular head and neck are of lateral plate mesodermal origin. (3) In contrast, the scapular blade is composed of somitic cells. (4) Unlike the Pax1-positive cells of the vertebral column, which are of sclerotomal origin, the Pax1-positive cells of the scapular blade originate from the dermomyotome. (5) Finally, we show that cells of the scapular blade are organised into spatially restricted domains along its rostrocaudal axis in the same order as the somites from which they originated. Our results imply that the scapular blade is an ossifying muscular insertion rather than an original skeletal element, and that the scapular head and neck are homologous to the 'true coracoid' of higher vertebrates.

Animals↗

PubMed2000

The provision of occlusal splints in primary dental care.

UNLABELLED: Occlusal splints (Michigan splints, night/bite guards or bite-raising appliances) can be an effective, inexpensive and reversible treatment for a wide range of dental problems. OBJECTIVE: The aim of this study was to analyse retrospectively the provision of occlusal splint ('Michigan' type) in general dental practice, following a prescription by a restorative dental consultant. METHOD: One hundred patients were recruited from consultant clinics in a department of conservative dentistry during 1995 and 1996. All patients were prescribed a maxillary, full-coverage, heat-cured, acrylic-resin splint (Michigan splint) as part of a treatment plan. An explanatory letter and questionnaire were sent to all patients and to their referring general dental practitioner in 1997 and 1998. RESULTS: A response rate of 79% was achieved in obtaining completed questionnaires from both patients and general dental practitioners. Of respondents 43% (34/79) received an occlusal splint of some form. A small proportion of the respondents (16.5% [13/79]) received a Michigan splint as prescribed. Irrespective of the type of appliance provided, most patients (82% [28/34]) found them helpful. Of those who did not receive an occlusal splint, 38% (17/45) of patients felt financial implications deterred them from obtaining an appliance. Other common reasons for non-provision included: patients felt that symptoms had improved (18% [8/45]) and patients did not agree with treatment (18% [8/45]). The general dental practitioners had similar opinions to their patients. DISCUSSION: These findings raise some serious doubts on the efficacy of consultant clinic advice in the prescription of occlusal splints in general dental practice. The financial and educational issues raised by this study will need to be addressed to improve service provision. CONCLUSION: The results of this study indicate that 16.5% of patient respondents prescribed a Michigan splint at a consultant clinic received such an appliance in general dental practice.

Comprehensive Dental Care↗

PubMed2000

Effects of follistatin and BMP4 proteins on early dorso-ventral patterning in chick.

In Xenopus and zebrafish certain bone morphognetic proteins (BMPs), and proteins that antagonise these by preventing their interaction with receptors, constitute a morphogen system in primary dorso-ventral patterning. This system may be directly involved in the parallel processes, within mesoderm and ectoderm, whereby the boundaries of the dorsal (paraxial) mesoderm and the neural plate are established. The bird blastoderm, amenable to grafting techniques and to direct exposure to specific proteins, has provided an opportunity to explore the phylogenetic conservation of such antagonistic system. We have grafted the gastrular organiser (node) into hosts, testing the effects of prior exposure of either grafted or host tissue to Follistatin (a known antagonist of TGFbeta superfamily ligands including BMP4) or to BMP4 protein. Strong, converse effects are seen from the two agents, the most consistent being on the sizes of new dorsalised areas (second neural plates) induced in host epiblast. Follistatin also enhances extension movements due to grafts, though without clear effect upon the rostro-caudal completeness of new patterns. Neural induction in chick epiblast by grafted mouse nodes are also more extensive, after their pre-incubation in Follistatin. Follistatin potentiates other, unknown but distinctive signals coming from the node, being unable to convert other non-inducing pieces of blastoderm into organisers on grafting. Pre-incubation of early blastoderms in BMP4 has such profound effects on normal dorsal axial development that host responsiveness of these blastoderms as hosts to node grafts is difficult to assess. Follistatin has no such overt effect on host development, but greatly enhances the competence of host epiblast to grafts of untreated nodes. Early chick BMP4 and BMP7 expressions are consistent with the proposed roles, though Follistatin is probably an experimental tool only in the present study.

Animals↗

PubMed2000

New insights into the mechanisms of lipid-body biogenesis in plants and other organisms.

A comparative approach has been used to study the role of several lipid-body-binding proteins in plants and animals. Caleosins are a newly discovered class of calcium-binding lipid-body proteins found in plants and fungi, which we now report to have separate endoplasmic reticulum- and lipid-body-associated isoforms. We also compare the lipid-body targeting of oleosin from plants and the core protein of the hepatitis C virus when they were expressed separately in lipid-accumulating animal cell lines. This is a novel and powerful approach to investigating the factors that determine the lipid-body targeting of a wide range of proteins.

Animals↗

PubMed1999

Urinary thymine dimers and 8-oxo-2'-deoxyguanosine in psoriasis.

Psoralen in conjunction with UVA (PUVA) is perhaps the most effective treatment for psoriasis. It is, however, a risk factor for skin cancer in these patients and there is a need to develop non-invasive assays reflective of treatment-induced DNA damage. We report here the assessment of two important lesions, thymine dimer (T<>T) and 8-oxo-2'-deoxyguanosine (8-OHdG), in the urine of psoriasis patients. It was found that, once corrected for urine concentration, the psoriatic group had significantly higher (P<0. 0001) urinary levels of thymine dimers compared to the control group. No significant differences in urinary 8-OHdG levels were noted between the psoriatic, atopic dermatitis and control groups. Therefore biomonitoring of therapy from the very start with this simple and non-invasive assay could perhaps be an effective measure of the risk involved with the treatment allowing optimization for minimal-risk therapy.

8-Hydroxy-2'-Deoxyguanosine↗