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Biomedical subjects

P Patel

Publications and source records attributed to P Patel.

At least 55 records · Page 3Linked to original sources
PubMed2001

Food analyses using molecularly imprinted polymers.

Molecular imprinting technology (MIT) is a technique for generating polymers bearing biomimetic receptors. It offers several advantages to the agrofood industry in areas such as analysis, sensoring, extraction, or preconcentration of components. It has the potential of becoming a tool for acquiring truly simple, rapid, and robust direct measurements. In this review, the special features of MIT that have bearing on food science and technology are highlighted.

Chromatography↗
PubMed2001

Soundbites.

Dentinogenesis imperfecta (DGI) is characterized by discolored teeth with an opalescent sheen and dentin that fails to support enamel, causing it to easily chip. Two new studies show that DGI is associated with mutations in DSPP, a gene encoding dentin sialophosphoprotein that is processed into two proteins: dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). These are key components of the dentin extracellular matrix (DECM). Notably, missense mutations in DSPP are also associated with progressive hearing loss.

Deafness↗
PubMed2001

The treatment of moderate to severe psoriasis with a new anti-CD11a monoclonal antibody.

BACKGROUND: Anti-CD11a (hu1124) is a humanized monoclonal antibody directed against the CD11a subunit of LFA-1. This study investigated whether treatment with anti-CD11a antibody provides clinical benefit to patients with moderate to severe plaque psoriasis. METHODS: This was a double-blind, placebo-controlled, phase II, multicenter study. In total, 145 patients with minimum Psoriasis Area and Severity Index scores of 12 and affected body surface area of 10% or more were sequentially enrolled into low-dose (0.1 mg/kg, n = 22) or high-dose (0.3 mg/kg, n = 75) groups. Within groups, patients were randomized to treatment or placebo (n = 48) in a 2:1 ratio. Drug was administered intravenously at weekly intervals for 8 weeks. RESULTS: The percentage of subjects achieving more than 50% improvement in physician's global assessment at day 56 (1 week after final dose) was 15% and 48% for placebo and 0.3 mg/kg of drug, respectively (P =.002). A physician's global assessment of excellent (>75% improvement) was greater in the 0.3 mg/kg group versus placebo (25% vs 2%, P =.0003). Average Psoriasis Area and Severity Index scores at day 56 were 13.9 +/- 7.5 (placebo) and 10.9 +/- 8.4 (0.3 mg/kg) (P <.0001). Epidermal thickness was reduced in the 0.3 mg/kg group compared with the placebo group (37% vs 19%, P =.004). Treatment was well tolerated; mild to moderate flu-like complaints were the most common adverse events. White blood cell counts and lymphocyte counts transiently increased. Depletion of circulating lymphocytes did not occur. CONCLUSIONS: Anti-CD11a antibody administered intravenously in 8 weekly doses of 0.3 mg/kg was well tolerated and induced clinical and histologic improvements in psoriasis.

Adult↗
PubMed2001

Diagnosis and management of chronic pericardial effusions.

Chronic pericardial effusions are a major cause of morbidity in some clinical settings. Although the treatment of choice for acute symptomatic pericardial effusions (tamponade) is pericardiocentesis, the long-term management of symptomatic chronic pericardial effusions provides a greater challenge. The aim of this review is to provide insight into the presentation,diagnosis, and different treatment options available to patients with chronic symptomatic pericardial effusions,with emphasis on malignant pericardial effusions. Peri-cardiocentesis with sclerosing agents, radiation therapy,percutaneous, and surgical pericardiotomy and other surgical techniques are particularly efficacious, depend-ing on the underlying cause and the patient's prognosis.

Balloon Occlusion↗
PubMed2001

Fas-mediated apoptosis of neutrophils in sera of patients with infection.

In the presence of infection, neutropenia is considered to be a marker of poor prognosis; conversely, neutrophilia may not be a determinant of a better prognosis. Since apoptotic neutrophils are compromised functionally, we evaluated the effect of infection on neutrophil apoptosis. The rate of apoptosis was greater for neutrophils isolated from patients with infection than for healthy controls. Escherichia coli did not directly modulate the rate of neutrophil apoptosis. However, sera from infected patients promoted (P < 0.001) neutrophil apoptosis. Interestingly, the sera of patients with different types of infection (gram negative, gram positive, or culture negative) exerted a more or less identical response on neutrophil apoptosis. Sera of infected patients showed a fivefold greater content of FasL compared to controls. Moreover, anti-FasL antibody partly attenuated the infected-serum-induced neutrophil apoptosis. In in vitro studies, E. coli enhanced monocyte FasL expression. Moreover, conditioned media prepared from activated macrophages from control mice showed enhanced apoptosis of human as well as mouse neutrophils. On the contrary, conditioned media prepared from activated macrophages isolated from FasL-deficient mice induced only a mild degree of neutrophil apoptosis. These results suggest that neutrophils in patients with infection undergo apoptosis at an accelerated rate. Infection not only promoted monocyte expression of FasL but also increased FasL content of the serum. Because the functional status of apoptotic cells is compromised, a significant number of neutrophils may not be participating in the body's defense. Since neutrophils play the most important role in innate immunity, their compromised status in the presence of infection may transfer the host defense burden from an innate response to acquired immunity. The present study provides some insight into the lack of correlation between neutrophilia and the outcome of infection.

Adult↗
PubMed2001

Elevated cytokine and chemokine levels and prolonged pulmonary airflow resistance in a murine Mycoplasma pneumoniae pneumonia model: a microbiologic, histologic, immunologic, and respiratory plethysmographic profile.

Because Mycoplasma pneumoniae is hypothesized to play an important role in reactive airway disease/asthma, a comprehensive murine model of M. pneumoniae lower respiratory infection was established. BALB/c mice were intranasally inoculated once with M. pneumoniae and sacrificed at 0 to 42 days postinoculation. All mice became infected and developed histologic evidence of acute pulmonary inflammation, which cleared by 28 days postinoculation. By contrast, M. pneumoniae persisted in the respiratory tract for the entire 42 days studied. Tumor necrosis factor alpha, gamma interferon, interleukin-6 (IL-6), KC (functional IL-8), MIP-1alpha, and MCP-1/JE concentrations were significantly elevated in bronchoalveolar lavage samples, whereas IL-4 and IL-10 concentrations were not significantly elevated. Pulmonary airflow resistance, as measured by plethysmography, was detected 1 day postinoculation and persisted even after pulmonary inflammation had resolved at day 28. Serum anti-M. pneumoniae immunoglobulin G titers were positive in all mice by 35 days. This mouse model provides a means to investigate the immunopathogenesis of M. pneumoniae infection and its possible role in reactive airway disease/asthma.

Airway Resistance↗
PubMed2001

Hyperkalaemic quadriparesis secondary to chronic diclofenac treatment.

A 76 year old woman presented with a quadriparesis associated with hyperkalaemia. She had a 10 month history of treatment with oral diclofenac sodium. On admission she had hyperkalaemic metabolic acidosis with a normal anion gap and mild renal impairment. Her weakness resolved after withdrawal of diclofenac and medical correction of her hyperkalaemia. Non-steroidal anti-inflammatory drugs are known to cause hyperkalaemic acidosis and should be used with caution, especially in the presence of renal impairment.

Aged↗
PubMed2001

Hemifacial microsomia. Etiology, diagnosis and treatment.

BACKGROUND: Three percent of all newborns have significant structural anomalies. Hemifacial microsomia, or HFM, is the second most common facial anomaly, second only to cleft lip and palate. New therapeutic and clinical management techniques offer promising interventions that can allow many patients to have more normal childhoods at earlier ages. DESCRIPTION: Due to a unilateral deficiency of the mandible and lower face, patients who have HFM have specific dental needs that require restorative, orthodontic and surgical correction. CLINICAL IMPLICATIONS: Oral and maxillofacial malformations present diagnostic and treatment challenges unique to the dental profession. The etiology, diagnosis and treatment modalities discussed in this article can be used to help effectively rehabilitate patients who have HFM.

Child↗
PubMed2001

Adherence to oral montelukast and inhaled fluticasone in children with persistent asthma.

STUDY OBJECTIVE: To evaluate adherence to oral montelukast and inhaled fluticasone in children with persistent asthma and to determine if age, monotherapy, and duration of therapy affect adherence. DESIGN: Retrospective analysis. SETTING: Pediatric pulmonary clinic. PATIENTS: One hundred seventy-one children with asthma who required continuous treatment with a controller agent year-round and in whom montelukast and/or fluticasone had been prescribed for at least 90 days. INTERVENTION: Montelukast monotherapy had been prescribed for 54 patients, fluticasone monotherapy for 48 patients, and combination therapy for 69 patients. MEASUREMENTS AND MAIN RESULTS: Prescription refill histories were obtained from pharmacies identified by the parents or from Medicaid pharmacy reimbursement records. The maximum possible adherence was calculated as [(no. of doses refilled)/(no. of doses prescribed)] x 100, for a mean observation period of 203 days (range 84-365 days) for montelukast and 314 days (range 97-365 days) for fluticasone. Median adherence rates were 59% (95% confidence interval [CI] 48-65%) for montelukast and 44% (90% CI 35-50%) for fluticasone. Adherence did not significantly correlate with age, length of observation period, or whether the patient was receiving monotherapy or combination therapy. The odds ratio for very poor adherence (< 50%) was 2.0 (95% CI 1.3-3.2) for fluticasone relative to montelukast. CONCLUSIONS: Adherence to both drugs was suboptimal. However, these data indicate that our patients were likely to take montelukast more consistently than fluticasone. Whether this translates into better asthma control requires further study.

Acetates↗
PubMed2001

An outbreak of syphilis in Alabama prisons: correctional health policy and communicable disease control.

OBJECTIVES: After syphilis outbreaks were reported at 3 Alabama State men's prisons in early 1999, we conducted an investigation to evaluate risk factors for syphilis infection and describe patterns of syphilis transmission. METHODS: We reviewed medical, patient interview, and prison transfer records and documented sexual networks. Presumptive source cases were identified. Odds of exposure to unscreened jail populations and transfer from other prisons were calculated for case patients at 1 prison. RESULTS: Thirty-nine case patients with early syphilis were identified from 3 prisons. Recent jail exposure (odds ratio [OR] = 8.0, 95% confidence interval [CI] = 0.3, 158.7, P = .14) and prison transfer (OR = 32.0, 95% CI = 1.6, 1668.1, P < .01) were associated with being a source case patient. CONCLUSIONS: Probable sources of syphilis introduction into and transmission within prisons included mixing of prisoners with unscreened jail populations, transfer of infected inmates between prisons, and multiple concurrent sexual partnerships. Reducing sexual transmission of disease in correctional settings is a public health priority and will require innovative prevention strategies.

AIDS Serodiagnosis↗
PubMed2001

Pharmacogenetics: the therapeutic drug monitoring of the future?

Genetic variability in drug response occurs as a result of molecular alterations at the level of drug-metabolising enzymes, drug targets/receptors, and drug transport proteins. In this paper, we discuss the possibility that therapeutic drug monitoring (TDM) in the future will involve not the mere measurement and interpretation of drug concentrations but will include both traditional TDM and pharmacogenetics-oriented TDM. In contrast to traditional TDM, which cannot be performed until after a drug is administered to the patient. pharmacogenetics-oriented TDM can be conducted even before treatment begins. Other advantages of genotyping over traditional TDM include, but are not limited to, the following: (i) it does not require the assumption of steady-state conditions (or patient compliance) for the interpretation of results; (ii) it can often be performed less invasively (with saliva, hair root or buccal swab samples); (iii) it can provide predictive value for multiple drugs [e.g. a number of cytochrome P450 (CYP) 2D6, CYP2C 19 or CYP2C9 substrates] rather than a single drug; (iv) it provides mechanistic, instead of merely descriptive, information; and (v) it is constant over an individual's lifetime (and not influenced by concurrent drug administration, alteration in hormonal levels or disease states). Pharmacogenetic information can be applied a priori for initial dose stratification and identification of cases where certain drugs are simply not effective. However, traditional TDM will still be required for all of the reasons that we use it now. In current clinical practice, pharmacogenetic testing is performed for only a few drugs (e.g. mercaptopurine, thioguanine, azathioprine, trastuzumab and tacrine) and in a limited number of teaching hospitals and specialist academic centres. We propose that other drugs (e.g. warfarin, phenytoin, codeine, oral hypoglycaemics, tricyclic antidepressants, aminoglycosides, digoxin, cyclosporin, cyclophosphamide, ifosfamide, theophylline and clozapine) are potential candidates for pharmacogenetics-oriented TDM. However, prospective studies of phaymacogenetics-oriented TDM must be performed to determine its efficacy and cost effectiveness in optimising therapeutic effects while minimising toxicity. In the future, in addition to targeting a patient's drug concentrations within a therapeutic range, pharmacists are likely to be making dosage recommendations for individual drugs on the basis of the individual patient's genotype. As we enter the era of personalised drug therapy, we will be able to identify not only the best drug to be administered to a particular patient, but also the most effective and safest dosage from the outset of therapy.

Cytochrome P-450 Enzyme System↗
PubMed2000

Mechanism and prevention of cold storage-induced human renal tubular cell injury.

BACKGROUND: The recent observation that cold storage of kidneys and tubular cells causes marked increase in free radical-catalyzed F2-isoprostanes suggests that radicals might be formed during cold storage. As cold temperature is associated with reduced metabolic and enzymic activity, the notion that cold temperature causes free radical production appeared less tenable. The objective was, therefore, to seek direct evidence for the free radical production during the cold storage of human renal tubular cells, and to define the roles of extrinsic and intrinsic antioxidants in cold-induced cell injury. METHODS: Human renal tubular cells were cold-stored at 4 degrees C for varying duration in University of Wisconsin solution and subjected to mRNA analysis, biochemical measurements, and cytoprotective studies. RESULTS: Cold storage caused a time-dependent reduction in glutathione levels, and an increase in the formation superoxide, hydrogen peroxide, and hydroxyl radicals. Cold-induced lactate dehydrogenase (LDH) release, ATP depletion, DNA damage, and membrane degradation were suppressed with the inclusion of antioxidant 2-methyl aminochroman or deferroxamine. The cells that were structurally protected with antioxidants were also intact functionally, as they had significantly improved cell proliferation. To examine the effect of cold on intrinsic antioxidant gene expression, antioxidant mRNA levels were analyzed using reverse transcription-polymerase chain reaction. The gene expression of mitochondrial Mn-superoxide dismutase (SOD), but not of cytosolic Cu,Zn-SOD or of glutathione peroxidase expression increased with cold exposure. The oxidant-sensitive gene heme oxygenase I increased slightly with 48-hr cold storage. CONCLUSIONS: Cold storage of human tubular cells causes marked increase in free radicals. These are likely of mitochondrial origin as there is a differential inducement of Mn-SOD gene, and are causal to cold-induced cell injury as extrinsic antioxidants abrogated the injury. Our findings support the strategy of adding antioxidants to preservation solutions or the strategy of pre-conditioning the organs to oxidative stress to minimize cold storage-induced organ damage.

Adenosine↗
PubMed2000

Influence of vitamin D deficiency and vitamin D receptor polymorphisms on tuberculosis among Gujarati Asians in west London: a case-control study.

BACKGROUND: Susceptibility to disease after infection by Mycobacterium tuberculosis is influenced by environmental and host genetic factors. Vitamin D metabolism leads to activation of macrophages and restricts the intracellular growth of M. tuberculosis. This effect may be influenced by polymorphisms at three sites in the vitamin D receptor (VDR) gene. We investigated the interaction between serum vitamin D (25-hydroxycholecalciferol) concentrations and VDR genotype on susceptibility to tuberculosis. METHODS: This study was a hospital-based case-control analysis of Asians of Gujarati origin, a mainly vegetarian immigrant population with a high rate of tuberculosis. We typed three VDR polymorphisms (defined by the presence of restriction endonuclease sites for Taq1, Bsm1, and Fok1) in 91 of 126 untreated patients with tuberculosis and 116 healthy contacts who had been sensitised to tuberculosis. Serum 25-hydroxycholecalciferol was recorded in 42 contacts and 103 patients. FINDINGS: 25-hydroxycholecalciferol deficiency was associated with active tuberculosis (odds ratio 2.9 [95% CI 1.3-6.5], p=0.008), and undetectable serum 25-hydroxycholecalciferol (<7 nmol/L) carried a higher risk of tuberculosis (9.9 [1.3-76.2], p=0.009). Although there was no significant independent association between VDR genotype and tuberculosis, the combination of genotype TT/Tt and 25-hydroxycholecalciferol deficiency was associated with disease (2.8 [1.2-6.5]) and the presence of genotype ff or undetectable serum 25-hydroxycholecalciferol was strongly associated with disease (5.1 [1.4-18.4]). INTERPRETATION: 25-hydroxycholecalciferol deficiency may contribute to the high occurrence of tuberculosis in this population. Polymorphisms in the VDR gene also contribute to susceptibility when considered in combination with 25-hydroxycholecalciferol deficiency.

Calcifediol↗
PubMed2000

Use of biotin-labeled nucleic acids for protein purification and agarose-based chemiluminescent electromobility shift assays.

We have employed biotin-labeled RNA to serve two functions. In one, the biotin tethers the RNA to streptavidin-agarose beads, creating an affinity resin for protein purification. In the other, the biotin functions as a label for use in a modified chemiluminescent electromobility shift assay (EMSA), a technique used to detect the formation of protein-RNA complexes. The EMSA that we describe avoids the use not only of radioactivity but also of neurotoxic acrylamide by using agarose as the gel matrix in which the free nucleic acid is separated from protein-nucleic acid complexes. After separation of free from complexed RNA in agarose, the RNA is electroblotted to positively charged nylon. The biotin-labeled RNA is readily bound by a streptavidin-alkaline phosphatase conjugate, allowing for very sensitive chemiluminescent detection ( approximately 0.1-1.0 fmol limit). Using our system, we were able to purify both known iron-responsive proteins (IRPs) from rat liver and assess their binding affinity to RNA containing the iron-responsive element (IRE) using the same batch of biotinylated RNA. We show data indicating that agarose is especially useful for cases when large complexes are formed, although smaller complexes are even better resolved.

Animals↗
PubMed2000

High-dose intra-arterial cisplatin and concurrent hyperfractionated radiation therapy in patients with locally advanced primary squamous cell carcinoma of the head and neck: report of a phase II study.

BACKGROUND: This phase II study evaluates the tolerability and efficacy of concurrent hyperfractionated radiation therapy (HFX-RT) and high-dose intra-arterial (IA) cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN). METHODS: Between December 1995 and November 1997, 20 patients with locally advanced T4/T3 SCCHN were treated with HFX-RT (76.8-79.2 Gy at 1.2 Gy bid over 6-7 weeks) and high-dose IA cisplatin (150 mg/m(2) given at the start of RT boost treatment [start of week 6]). Seventeen patients (85%) had T4 disease, and 14 (70%) had N2/ N3 disease. RESULTS: Grade 3-5 acute toxicity was limited to one grade 4 (5%) and 14 grade 3 (70%) mucosal events. No grade 3/4 hematologic toxicity was observed. Median weight loss during therapy was 9% (range, 2%-16%). Eighteen patients had complete response (90%) at the primary site; 14 were confirmed pathologically. Among 17 patients with positive neck disease, 16 (94%) achieved complete response in the neck, including 12 of 13 patients with N2/N3 disease who underwent planned neck dissection. Active follow-up ranges from 12 to 32 months (median, 20 months) with 11 patients alive without disease, 5 dead of disease, and 4 dead of intercurrent disease. Eighteen patients (90%) remained disease free at the primary site, and the locoregional control rate is 80%. CONCLUSIONS: High-dose IA cisplatin and concurrent HFX-RT as used in this study is feasible and warrants further investigation. The high complete response rate and low grade 4 toxicity in this highly unfavorable subset of patients appears better than previously reported chemoradiation regimens for more favorable patients.

Adult↗
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↗