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Biomedical subjects

H Patel

Publications and source records attributed to H Patel.

At least 127 records · Page 7Linked to original sources
PubMed1998

Spontaneous spinal epidural hematoma in children.

Spontaneous spinal epidural hematoma is rare in children. It is usually confined to the dorsal epidural space. Ventral spontaneous spinal epidural hematoma (SSEH) is rarer, with only two previous reports. The authors present three children, two with dorsal and one with ventral spinal epidural hematoma, and review the literature. No etiology of the hematoma was found in the authors' patients and there was no history of trauma. A review of 24 patients of children younger than 18 years of age reported in the literature and the authors' three patients revealed that the cervicothoracic region was the most common site of SSEH, the mode of onset was frequently subacute, and there was no male preponderance as has been reported in adults. We found that the initial symptoms were often nonspecific, leading to a delay in diagnosis, especially in younger children. Follow-up data revealed that 15 of the 27 patients recovered completely, 11 had residual neurologic deficits, and one patient died. Irritability and neck pain with restricted movements of the cervical spine in an afebrile child may be early signs of SSEH and often precede onset of neurologic deficits by several hours to days. These signs should alert the clinician to consider spinal epidural hematoma and the need for urgent magnetic resonance imaging (MRI) of the spine for early diagnosis and treatment to minimize morbidity.

Child, Preschool↗
PubMed1998

Human serum amyloid A has cytokine-like properties.

Human serum amyloid A (SAA) proteins are a group of 12-14 kDa apolipoproteins found predominantly in the high-density lipoprotein (HDL) fraction of plasma. Several functions have been proposed for SAA, but its primary physiological function remains elusive. In this report, we used the monocytic cell line THP-1 to investigate whether recombinant SAA1 (rSAA) or the HDL-rSAA protein complex can affect the capacity of these cells to produce inflammatory cytokines in vitro. Incubation of rSAA, plasma HDL (which contains < or = 30 microg/ml of SAA) or HDL-rSAA complex with THP-1 cells induced synthesis of IL-1beta, IL-1ra and sTNFR-II protein and mRNA. The induction of cytokine synthesis was not due to endotoxin contamination since the effect was abrogated by protein denaturation. The rSAA and HDL-rSAA complex did not induce detectable levels of IL-6 or TNFalpha protein or mRNA. In contrast 10 microg/ml LPS stimulated secretion of the inflammatory cytokines, IL-1beta, IL-6 and TNFalpha, as well as IL-1ra and sTNFR-II from THP-1 cells. We confirmed that rSAA has chemoattractant properties in vivo, by subcutaneous injections into mice and examined the histology of the injection site at 72 h, however, the HDL-rSAA complex has a substantially reduced effect.

Animals↗
PubMed1998

Cost effectiveness of electrohydraulic lithotripsy v Candela pulsed-dye laser in management of the distal ureteral stone.

To compare the efficacy, safety, and cost of the Candela laser lithotripter with those of the electrohydraulic (EHL) lithotripter in the management of distal ureteral stones, 24 patients with obstructing stones were randomized to laser lithotripsy or EHL. Ureteroscopy was performed with a 6.9F ACMI Miniscope under general anesthesia. Twelve patients were treated with laser lithotripsy using the Candela Air-Cooled MDL 2000 LaserTripter System with a 200-micron pulsed-dye laser fiber. Twelve patients were treated with the Herzog Electrohydraulic LithoTripter using the 1.9F fiber. The following issues were studied: stone-free rates, complications (intraoperative, postoperative, and late), and costs of the procedure. No difference was found in the stone-free or complication rates. One patient was found to have hydronephrosis at 6 months secondary to an unrelated proximal ureteral stone. There was no difference in the efficacy of laser lithotripsy and EHL in the management of distal ureteral stones, but EHL was found to be significantly more cost effective: the cost for EHL was +336 per case, whereas, the cost for lasertripsy was +4220 per case, a greater than 10-fold difference.

Adult↗
PubMed1998

Results of Helicobacter pylori screening and eradication in a multi-ethnic community in central England.

OBJECTIVES: To determine the prevalence of Helicobacter pylori and risks for infection in a multi-ethnic inner city population, and to assess the effectiveness with which the infection can be eradicated in a relatively asymptomatic population of this type. DESIGN: Analysis of results from a small research-based community programme of screening and eradication. Tests were offered to matched groups of Asians and non-Asians from the general population. METHODS: Those who attended for screening had a serological screening test for infection with H. pylori. Data concerning possible risk factors for infection were collected by means of questionnaires. Subjects testing positive were offered a prescription for eradication therapy (ranitidine bismuth citrate and clarithromycin) through their general practitioner, and success of eradication therapy was assessed by urea breath test. RESULTS: The overall prevalence of infection in 155 subjects was found to be 51%. The difference between positive test rates in Asians (53%) and non-Asians (47%) was not significant (P=0.611). In Asians, age and social class were risk factors for infection, but not gender or birth outside the UK. Results were similar in those born in India and East Africa. Of the 79 people who tested positive, 64 (81%) elected to take eradication therapy. Compliance with medication was estimated to be 95% and successful eradication was achieved in 92% of cases. CONCLUSION: Social class is more important than Asian ethnic origin as a predictor of H. pylori status. Good rates of H. pylori eradication can be achieved in subjects from the general population living in inner city communities.

Breath Tests↗
PubMed1998

Maltose and isomaltose in uremic plasma following icodextrin administration.

The presence of mixed disaccharides (maltose and isomaltose) in plasma from uremic patients has been previously investigated using gel-permeation chromatography. However, this method is unable to separate maltose (linked alpha-1-4) from isomaltose (linked alpha-1-6). We describe an alternative method using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD) for the direct determination of maltose and isomaltose in uremic plasma. We measured maltose and isomaltose using HPAE-PAD in 6 normal subjects and in 15 uremic patients before and after once-daily icodextrin administration for at least 4 weeks. Both maltose and isomaltose were below limits of detection (< 1.0 mg/L) in plasma from normal controls. Patients with end-stage renal disease treated by continuous ambulatory peritoneal dialysis had elevated levels of isomaltose (23.6 +/- 8.3 mg/L) but low levels of maltose (< 3.0 mg/L). Treatment with icodextrin resulted in elevated plasma levels of maltose (range: 500-1600 mg/L), while levels of isomaltose declined to 9.8 +/- 5.2 mg/L (P < 0.0001 vs. baseline levels). We conclude that isomaltose (not maltose) is the primary disaccharide isomer that is elevated in the plasma of uremic patients, whereas maltose is the primary disaccharide isomer that is elevated following icodextrin administration. Furthermore, icodextrin administration results in an apparent reduction of isomaltose. Additional investigation will be required to address the mechanism for the reduction of isomaltose in patients treated by icodextrin.

Chromatography, High Pressure Liquid↗
PubMed1998

Teamwork in the operating department.

The Gynaecology theatre team of the Leicester Royal Infirmary NHS Trust were runners-up in the 1997 3M/NATN joint award. This article is a report of their work on the concept of teamwork and its benefits to the organisation and delivery of patient care in the operating department.

Hospital Restructuring↗
PubMed1998

Biochemical characterization of recombinant factor IX.

Mature human factor IX is a 55,000-d glycoprotein with a modular domain structure and numerous posttranslational modifications. A recombinant form of human factor IX (rFIX) has been produced from a Chinese hamster ovary cell line that was engineered for high-level protein processing and expression. To ensure that the recombinant molecule contains the requisite structural and functional features of the plasma-derived form, rFIX was subjected to detailed biochemical and biophysical characterization. The laboratory studies showed that the posttranslational modifications and primary, secondary, and tertiary structures of rFIX were similar to those of plasma-derived factor IX (pdFIX). In addition, rFIX displayed a high degree of purity and a product release specification for specific activity that is > or = 200 IU/mg.

Amino Acid Sequence↗
PubMed1998

Drugs for conversion of atrial fibrillation.

Atrial fibrillation is the most common arrhythmia in patients visiting a primary care practice. Although many patients with atrial fibrillation experience relief of symptoms with control of the heart rate, some patients require restoration of sinus rhythm. External direct current (DC) cardioversion is the most effective means of converting atrial fibrillation to sinus rhythm. Pharmacologic cardioversion, although less effective, offers an alternative to DC cardioversion. Several advances have been made in antiarrhythmic medications, including the development of ibutilide, a class III antiarrhythmic drug indicated for acute cardioversion of atrial fibrillation. Other methods of pharmacologic and nonpharmacologic cardioversion remain under development. Until the results of several large-scale randomized clinical trials are available, the decision to choose cardioversion or maintenance of sinus rhythm must be individualized, based on relief of symptoms and reduction of the morbidity and mortality associated with atrial fibrillation.

Acute Disease↗
PubMed1998

An inexpensive and easily constructed laparoscopic simulator.

In this short article the authors describe a simple yet effective method to train surgical trainees in minimally invasive surgery. This method will allow trainees to freely practice and acquire the necessary basic skills required to both competently assist and perform laparoscopic surgery.

Clinical Competence↗
PubMed1997

A classical enzyme active center motif lacks catalytic competence until modulated electrostatically.

The cysteine proteinase superfamily is a source of natural structural variants of value in the investigation of mechanism. It has long been considered axiomatic that catalytic competence of these enzymes mirrors the generation of the ubiquitous catalytic site imidazolium-thiolate ion pair. We here report definitive evidence from kinetic studies supported by electrostatic potential calculations, however, that at least for some of these enzymes the ion pair state which provides the nucleophilic and acid-base chemistry is essentially fully developed at low pH where the enzymes are inactive. Catalytic competence requires an additional protonic dissociation with a common pKa value close to 4 possibly from the Glu50 cluster to control ion pair geometry. The pH dependence of the second-order rate constant (k) for the reactions of the catalytic site thiol groups with 4,4'-dipyrimidyl disulfide is shown to provide the pKa values for the formation and deprotonation of the (Cys)-S-/(His)-Im+H ion pair state. Analogous study of the reactions with 2,2'-dipyridyl disulfide reveals other kinetically influential ionizations, and all of these pKa values are compared with those observed in the pH dependence of kcat/Km for the catalyzed hydrolysis of N-acetylphenylalanylglycine 4-nitroanilide. The discrepancy between the pKa value for ion pair formation and the common pKa value close to 4 related to generation of catalytic activity is particularly marked for ficin (pKa 2.49 +/- 0.02) and caricain (pKa 2.88 +/- 0.02) but exists also for papain (pKa 3.32 +/- 0.01).

Binding Sites↗
PubMed1997

Risk of incontinence with transurethral resection of the prostate after radiation therapy for prostate cancer.

BACKGROUND: It has been reported that transurethral resection of the prostate (TURP) after definitive radiation therapy for prostate cancer is associated with a significant risk of incontinence. The presumed reason for incontinence is external sphincter damage from TURP or pre-existing damage from either extension of prostate cancer or radiation therapy. METHODS: We reviewed seven recent cases of TURP for bladder outlet obstruction in patients who had undergone radiation therapy for clinical stage T(3-4)M(0)N(0) adenocarcinoma of the prostate. All seven men progressed to either chronic retention or debilitating obstructive symptoms with weak peak flows from 3.4 to 5.1 cc/s (mean 4 cc/s). Each of them subsequently underwent a limited TURP. RESULTS: Voiding symptoms were reduced in all patients and peak flows were improved to 6.3 to 20 cc/s (mean 14.8 cc/s) with mean follow-up 35 m. No patient developed stress urinary incontinence postoperatively. CONCLUSION: These results suggest that TURP can be performed successfully after radiation therapy with minimal risk of stress incontinence.

Adenocarcinoma↗
PubMed1997

gamma-Carboxyglutamic acids 36 and 40 do not contribute to human factor IX function.

The gamma-carboxyglutamic acid (Gla) domains of the vitamin K-dependent blood coagulation proteins contain 10 highly conserved Gla residues within the first 33 residues, but factor IX is unique in possessing 2 additional Gla residues at positions 36 and 40. To determine their importance, factor IX species lacking these Gla residues were isolated from heterologously expressed human factor IX. Using ion-exchange chromatography, peptide mapping, mass spectrometry, and N-terminal sequencing, we have purified and identified two partially carboxylated recombinant factor IX species; factor IX/gamma 40E is uncarboxylated at residue 40 and factor IX/gamma 36,40E is uncarboxylated at both residues 36 and 40. These species were compared with the fully gamma-carboxylated recombinant factor IX, unfractionated recombinant factor IX, and plasma-derived factor IX. As monitored by anti-factor IX:Ca (II)-specific antibodies and by the quenching of intrinsic fluorescence, all these factor IX species underwent the Ca(II)-induced conformational transition required for phospholipid membrane binding and bound equivalently to phospholipid vesicles composed of phosphatidylserine, phosphatidylcholine, and phosphatidylethanolamine. Endothelial cell binding was also similar in all species, with half-maximal inhibition of the binding of 125I-labeled plasma-derived factor IX at concentrations of 2-6 nM. Functionally, factor IX/gamma 36,40E and factor IX/gamma 40E were similar to fully gamma-carboxylated recombinant factor IX and plasma-derived factor IX in their coagulant activity and in their ability to participate in the activation of factor X in the tenase complex both with synthetic phospholipid vesicles and activated platelets. However, Gla 36 and Gla 40 represent part of the epitope targeted by anti-factor IX:Mg(II)-specific antibodies because these antibodies bound factor IX preferentially to factor IX/gamma 36,40E and factor IX/gamma 40E. These results demonstrate that the gamma-carboxylation of glutamic acid residues 36 and 40 in human factor IX is not required for any function of factor IX examined.

1-Carboxyglutamic Acid↗
PubMed1997

Efficient adenoviral-mediated murine neonatal small intestinal gene transfer is dependent on alpha(v) integrin expression.

BACKGROUND/PURPOSE: Clinical application of gene therapy for patients who have inflammatory bowel disease or short bowel syndrome will require the development of new strategies to improve the efficiency of small intestinal gene transfer. Previously, the authors developed a method for adenoviral-mediated small intestinal gene transfer in vivo in neonatal and adult mice. The present study evaluates the hypothesis that the integrins alpha(v)beta3 and alpha(v)beta5, the secondary receptors for adenoviral internalization, play a facilitative role in neonatal murine adenoviral-mediated small intestinal gene transfer. METHODS: Immunohistochemical techniques identified the integrin alpha(v)beta3 and the integrin subcomponents alpha(v), beta3, and beta5 in neonatal and adult small intestine. The effects of integrin receptor antagonists on transgene expression was also studied in our neonatal model of adenoviral-mediated small intestinal gene transfer in vivo. RESULTS: Gene transfer was significantly decreased by the addition of integrin receptor antagonists versus control peptide. Integrin alpha(v)beta3 and integrin subcomponent alpha(v), beta3, and beta5 are expressed in neonatal and adult small intestine. Integrin antagonists administered simultaneously blocked efficient adenoviral-mediated neonatal small intestinal gene transfer in vivo compared with control peptide. CONCLUSION: Strategies to upregulate integrin expression may improve adenoviral-mediated small intestinal gene transfer.

Adenoviruses, Human↗
PubMed1997

Corrosion of the intra-oral magnets by multi-species biofilms in the presence and absence of sucrose.

The purpose of this study was to determine the corrosive effects of multi-species biofilms on intra-oral magnets in the presence and absence of sucrose. Using pooled human saliva as an inoculum, biofilms were grown on the surfaces of 90 neodymium-iron-boron (Nd2Fe14B) magnets in a constant depth film fermentor under aerobic conditions at 37 degrees C. The fluid phase was a mucin-containing artificial saliva (delivered at a rate of 0.72/litres day-1), and, after 15 days, 100 ml of 10% (w/v) sucrose was added (as three pulses of 33.3 ml) each day for a further 15 days. Six magnets with attached biofilms were removed periodically. On each sampling occasion the numbers of aerobes, anaerobes, streptococci, veillonellae and actinomyces in each biofilm, the pH of the fermentor effluent and the dry mass of the magnets were determined. Addition of sucrose to the fermentor resulted in a fall in pH (from a mean of 6.94 to a mean of 4.96), an increase in the proportion of streptococci and a decrease in the proportion of veillonellae comprising the biofilms. The decrease in mass of the magnets was 28-fold greater in the presence of sucrose than in its absence. The results of this study have shown that the presence of sucrose affects the microbial composition of multi-species biofilms growing on Nd2Fe14B magnets and results in a marked increase in corrosion of the magnets.

Bacteria, Anaerobic↗
PubMed1997

Cross-talk between transcription factors NF-kappa B and C/EBP in the transcriptional regulation of genes.

The study of the acute phase response has attracted substantial interest, not only for its medical implication, but also its provision as an excellent system with which to elucidate the molecular mechanisms involved in the modulation of gene expression. Our previous data suggest that the synergistic induction of the major acute phase reactant serum amyloid A2 (SAA2) expression by interleukin-1 (IL-1) and interleukin-6 (IL-6) is mediated by two families of transcription factors, namely NF-kappa B and C/EBP. To understand the molecular mechanisms of this synergy, we have undertaken a molecular dissection of the factors involved in the formation of the regulatory complex. Electrophoretic mobility shift analysis indicates that NF-kappa B p65 (RelA) and p50, but not p52 or c-Rel, bind specifically to the NF-kappa B site of the SAA2 promoter in response to IL-1 stimulation. In addition, C/EBP beta and C/EBP delta, but not C/EBP alpha, bind specifically to the C/EBP site of SAA2 in response to IL-6 stimulation. Transient co-transfection analysis indicates that co-operative association of NF-kappa B p65 with C/EBP beta and, in particular, with C/EBP delta, results in synergistic transcriptional activation of the SAA2 promoter. When incubated together, NF-kappa B p65 and C/EBP beta form a ternary complex by direct protein/protein interaction. Mutational analysis demonstrates that the C-terminus region of the Rel homology domain (RHD) and the C-terminus of the activation domain of p65 are important for its interaction with C/EBP beta. These results suggest the NF-kappa B and C/EBP may form a new complex of transcription factors that mediates the synergistic induction of SAA2 by IL-1 and IL-6.

Acute-Phase Reaction↗
PubMed1997

Managing TMD.

Explore the source record for details and available documents.

American Dental Association↗
PubMed1997

Glucose-induced protein kinase C activation regulates vascular permeability factor mRNA expression and peptide production by human vascular smooth muscle cells in vitro.

Hyperglycemia is an independent risk factor for the development of diabetic microvascular disease. Vascular permeability factor (VPF)/vascular endothelial growth factor (VEGF) is a potent cytokine family that induces angiogenesis and markedly increases endothelial permeability. VPF is produced by many cell types, including vascular smooth muscle (VSM) cells, and has been implicated in the pathogenesis of neovascularization and endothelial dysfunction in diabetes. This study used cultured human VSM cells to study the regulation of VPF production and determine whether elevated glucose concentrations, per se, are a sufficient stimulus for increased VPF production by human cells. In human VSM cells, high extracellular glucose concentrations (20 mmol/l) increased VPF mRNA expression within 3 h (3-fold vs. glucose 5 mmol/l) and significantly increased VPF peptide production within 24 h (1.5-fold) in a time- and glucose concentration-dependent manner. The high glucose-induced increase in VPF mRNA expression was rapidly reversed after normalizing the extracellular glucose concentration and was specific for a high D-glucose concentration, as these effects were not reproduced by osmotic control media containing elevated concentrations of mannitol or L-glucose. High glucose concentrations activate protein kinase C (PKC) in human VSM cells, and PKC inhibitors (H-7 or chelerythrine chloride) or PKC downregulation each prevented the glucose-induced increases in VPF mRNA expression by human VSM cells. In conclusion, high glucose concentrations directly increase VPF mRNA expression and peptide production by human VSM cells via a PKC-dependent mechanism. These results demonstrate a cellular mechanism, whereby hyperglycemia could directly contribute to the development of endothelial dysfunction and neovascularization in diabetes.

Cells, Cultured↗