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Biomedical subjects

P Patel

Publications and source records attributed to P Patel.

At least 91 records · Page 5Linked to original sources
PubMed1999

Anaerobic upflow fixed-film bioreactor for biomethanation of salty cheese whey.

In order to develop a suitable reactor for the biomethanation of high-strength salty cheese whey, the performance of anaerobic upflow fixed-film reactors packed with different support materials, such as charcoal, gravel, brick pieces, pumice stones, and PVC pieces, has been studied. The charcoal-bedded reactor gave the best performance, with the maximum gas production (3.3 L/L digester/d) and an enriched methane content (69% CH4). Temperature and hydraulic retention time were optimized, with the ultimate aim of improving biomethanation. Maximum gas production (3.3 L/L digester/d) was achieved at a hydraulic retention time of 2 d at 40 degrees C.

Bioreactors↗
PubMed1999

Characteristics of cocaine users in a private inpatient treatment setting.

Patient records were reviewed from an eighteen-month period of a private hospital adult addictive disease unit. Of 667 consecutive admissions, sixty-five (49 males, 16 females) were diagnosed with cocaine abuse or dependence; 38 percent were from rural areas. Although mean age of males and females was similar, males had a longer duration of use (8.2 years versus 5.8 years), however, females used an average of 14 grams per week versus 9.5 grams per week for males. African-American patients were over-represented among the cocaine using sample and also among the sample who chose smoking as their route of administration. A larger percentage of males had legal problems and admitted to "dealing," when compared to females. Those from rural areas were more likely to be married and less apt to have legal problems.

Adult↗
PubMed1998

The vesicle transport protein Vps33p is an ATP-binding protein that localizes to the cytosol in an energy-dependent manner.

Molecular mechanisms of vesicle transport between the prevacuolar compartment and the vacuole in yeast or the lysosome in mammalian cells are poorly understood. To learn more about the specificity of this intercompartmental step, we have examined the subcellular localization of a SEC1 homologue, Vps33p, a protein implicated to function in transport between the prevacuolar compartment and the vacuole. Following short pulses, 80-90% of newly synthesized Vps33p cofractionated with a cytosolic enzyme marker after making permeabilized yeast cells. However, during a chase, 20-40% of Vps33p fractionated with permeabilized cell membranes in a time-dependent fashion with a half-time of approximately 40 min. Depletion of cellular ATP increased the association rate to a half-time of approximately 4 min and caused 80-90% of newly synthesized Vps33p to be associated with permeabilized cell membranes. The association of Vps33p with permeabilized cell membranes was reversible after restoring cells with glucose before permeabilization. The N-ethylmaleimide-sensitive fusion protein homologue, Sec18p, a protein with known ATP binding and hydrolysis activity, displayed the same reversible energy-dependent sedimentation characteristics as Vps33p. We determined that the photosensitive analog, 8-azido-[alpha-32P]ATP, could bind directly to Vps33p with low affinity. Interestingly, excess unlabeled ATP could enhance photoaffinity labeling of 8-azido-[alpha-32P]ATP to Vps33p, suggesting cooperative binding, which was not observed with excess GTP. Importantly, we did not detect significant photolabeling after deleting amino acid regions in Vps33p that show similarity to ATP interaction motifs. We visualized these events in living yeast cells after fusing the jellyfish green fluorescent protein (GFP) to the C terminus of full-length Vps33p. In metabolically active cells, the fully functional Vps33p-GFP fusion protein appeared to stain throughout the cytoplasm with one or two very bright fluorescent spots near the vacuole. After depleting cellular ATP, Vps33p-GFP appeared to localize with a punctate morphology, which was also reversible upon restoring cells with glucose. Overall, these data support a model where Vps33p cycles between soluble and particulate forms in an ATP-dependent manner, which may facilitate the specificity of transport vesicle docking or targeting to the yeast lysosome/vacuole.

Adenosine Triphosphatases↗
PubMed1998

Effects of timolol and betaxolol on choroidal blood flow in the rabbit.

This study evaluated the effects of the topical beta1-adrenergic antagonist betaxolol and the non-selective beta-adrenergic antagonist timolol on the choroidal pressure-flow relationship. Pentobarbital-anesthetized rabbits were instrumented with hydraulic occluders on the aorta and inferior vena cava to control MAP, an ear artery cannula to measure mean arterial pressure (MAP), and two vitreous cannulas to control and measure intraocular pressure (IOP). Choroidal blood flow was measured by laser Doppler flowmetry with the fiber-optic probe tip positioned over the posterior pole. Choroidal pressure-flow curves were obtained before and 30 min after topical application of 0.1 ml of betaxolol (Betoptic, 0.5%, n=10), timolol (Timoptic, 0.5%, n=10) or saline (n=8) by varying the MAP without controlling the IOP and by raising IOP while holding the MAP constant at 70 mmHg. The IOP was significantly reduced by betaxolol and timolol but not by saline. MAP was also slightly, but significantly, reduced after betaxolol but not after timolol or saline. However, the systemic hypotensive response to isoproterenol (8 microgram/kg, i.v.) was blunted after betaxolol and timolol indicating appreciable systemic absorption of both drugs. Timolol, but not betaxolol or saline, caused a significant, small increase in baseline choroidal vascular resistance. Timolol also attenuated the IOP response to MAP; however, none of the treatments had a significant effect on the choroidal pressure-flow relationship. We conclude that both drugs reach the systemic circulation after topical application, but neither betaxolol nor timolol alter the choroidal response to acute changes in perfusion pressure.

Adrenergic beta-Antagonists↗
PubMed1998

Mucoid encapsulated Enterococcus faecalis: an emerging morphotype isolated from patients with urinary tract infections.

Three strains of encapsulated Enterococcus faecalis, which produced highly mucoid coalescing colonies on routine bacteriologic media, were isolated from urine specimens of patients with urinary tract infection. Encapsulation could be demonstrated through India ink preparations. The occurrence of this unusual enterococcal colony morphotype, which resembles that of a Gram-negative bacterium, may delay true identification.

Aged↗
PubMed1998

Reliability and validity of the PAS-ADD Checklist for detecting psychiatric disorders in adults with intellectual disability.

The PAS-ADD Checklist is a screening instrument specifically designed to help staff recognize mental health problems in the people with intellectual disability for whom they care, and to make informed referral decisions. The instrument consists of a life-events checklist and 29 symptom items scored on a four-point scale. Scores are combined to provide three threshold scores. The crossing of any of these thresholds indicates the need for a fuller assessment. The items are worded in everyday language, making the Checklist suitable for use by individuals who do not have a background in psychopathology. The present paper presents the results of a number of studies evaluating the reliability and validity of the Checklist. Factor analysis of Checklists completed on a community sample of 201 individuals yielded eight factors, of which seven were readily interpretable in diagnostic terms. Internal consistency of the scales was generally acceptable. Inter-rater reliability in respect to individual items gave a fairly low average Kappa of 0.42. However, agreement on case identification, the main purpose of the Checklist, was quite good, with 83% of the decision being in agreement. Validity in relation to clinical opinion was also satisfactory, case detection rising appropriately with the clinically judged severity of disorder. The PAS-ADD Checklist is published and distributed by the Hester Adrian Research Centre, Manchester, England, from where further information and order forms are available on request.

Adolescent↗
PubMed1998

Reliability and validity of the Mini PAS-ADD for assessing psychiatric disorders in adults with intellectual disability.

The Mini PAS-ADD is an assessment schedule for psychiatric disorders in people with an intellectual disability. It is designed to provide a link between the mental health expertise of psychiatrists and psychologists, and the detailed knowledge of individual service users possessed by support staff. In broad terms, the aim of the Mini PAS-ADD is to enable non-psychiatrists accurately to recognize clinically significant psychiatric disorders in the people who they care for, so that they can make informed referral decisions. The instrument comprises 86 psychiatric symptoms and generates a series of subscores on: depression, anxiety and phobias, mania, obsessive-compulsive disorder, psychosis, unspecified disorder (including dementia), and pervasive developmental disorder (autism). The present paper reports the results of a study investigating internal consistency, inter-rater agreement and validity in relation to clinical opinion, using a sample of 68 people with intellectual disability who were in contact with psychiatric services. In terms of the instrument fulfilling its main intended function, i.e. accurate case recognition, the crucial question was whether the support workers, with their lesser knowledge of psychopathology, were also able to correctly identify cases identified by expert clinicians. The validity results in this respect (81% agreement on case recognition) were sufficiently good that it is to be anticipated that the Mini PAS-ADD should have a significant impact on the identification of psychiatric disorders in the community of people with intellectual disability.

Adult↗
PubMed1998

Patient-controlled sedation with propofol and alfentanil during colonoscopy: a pilot study.

BACKGROUND AND STUDY AIMS: Patient controlled sedation (PCS) is becoming increasingly popular in day-case surgery and has the potential for use during endoscopy. We aimed to examine its safety and acceptability during colonoscopy in a pilot study using alfentanil and propofol and assess its influence on the patient's recovery time. PATIENTS AND METHODS: Sixteen otherwise healthy patients undergoing colonoscopy were attached to a Graseby 3300 PCA pump containing propofol 400 mg and alfentanil 1 mg (total volume 42 ml) and gave themselves bolus of 0.5 ml whenever they became uncomfortable. RESULTS: All patients tolerated the procedure well and found the PCS easy to use. There were no serious haemodynamic or respiratory complications and patients recovered quickly after the procedure, irrespective of the dose of drug given. CONCLUSIONS: PCS with propofol and alfentanil is an effective, short-acting form of sedation for patients undergoing colonoscopy and may be an alternative to benzodiazepines.

Aged↗
PubMed1998

Patient-controlled sedation and analgesia, using propofol and alfentanil, during colonoscopy: a prospective randomized controlled trial.

BACKGROUND AND STUDY AIMS: Patient-controlled sedation (PCS) enables titration of dosage to an individual's requirements and is potentially useful in colonoscopy. The aim was to compare the value of patient-controlled sedation, using propofol and alfentanil, with that of intravenous diazemuls and pethidine during colonoscopy. PATIENTS AND METHODS: Following randomization, 66 patients undergoing colonoscopy received either an intravenous bolus of pethidine (50 mg) and diazemuls (10-20 mg) prior to colonoscopy or were connected to an infusion pump containing propofol (10 mg/ml) and alfentanil (25 microg/ml). Patients self-administered 0.5 ml boluses as often as they required. Pain and sedation score were recorded by a nurse specialist and on a patient questionnaire. An anaesthetist was present throughout the procedure. RESULTS: PCS provided lighter sedation (median sedation score, 3 versus 4; P=0.0001), less analgesia (median pain score, 1 versus 0; P=0.004), a smaller maximum fall in systolic blood pressure (23 mmHg versus 33 mmHg; P=0.02) and a faster recovery time (median 10 min versus 40 min; P=0.0001), irrespective of the dose administered, compared with a diazemuls-pethidine combination. The duration of the procedure was unaffected. All patients were satisfied with their level of sedation. CONCLUSIONS: Patient-controlled sedation is an effective alternative to premedication with narcotic/benzodiazepine combinations during colonoscopy.

Adult↗
PubMed1998

Mycoplasma pneumoniae pneumonia in a mouse model.

To investigate the pathogenesis of acute Mycoplasma pneumoniae infection, BALB/c mice were anesthetized with metofane, and M. pneumoniae was introduced intranasally on days 0, 1, and 2. Mice were sacrificed on days 0-15. A histopathologic scoring system defined inflammatory changes in the lungs on a scale of 0-26 (least to most severe). Broth cultures were positive for all nasal passage and bronchoalveolar lavage (BAL) specimens. Histopathologic scores ranged from 0 to 21. The mean log10 (cfu/mL) were 4.1-6.4 on days 1-10 and >/=1.7 on days 13-15 for nasal passage and BAL specimens. Serum polymerase chain reaction was negative. ELISA for serum IgM and immunoblots for M. pneumoniae antibody were positive in 21 (62%) of 34 and 33 (97%) of 34 infected animals, respectively, at days 8-15. ELISA for IgG antibody was negative. This mouse pneumonia model can be used to study the immunologic and therapeutic responses to acute M. pneumoniae infection.

Animals↗
PubMed1998

Second malignant neoplasia in patients with T1 glottic cancer treated with radiation.

OBJECTIVE/HYPOTHESIS: To evaluate incidence, site of occurrence and outcome of second malignant neoplasia (SMN) in patients with T1 glottic cancer treated with radiation. STUDY DESIGN: Retrospective. METHODS: Between February 1964 and May 1993, 158 patients with T1 squamous carcinoma of the larynx were treated with definitive radiation. Incidence, site (aerodigestive tract or not) and outcome of SMN were analyzed. Median follow-up was 63 months (range, 12-245 mo). RESULTS: Thirty-four patients developed SMN, for an overall incidence of 22%. Twenty-four (67%) SMNs occurred in an aero-upper-digestive-tract site compared with nine (25%) occurring in a non-aero-upper-digestive tract site. The incidence of SMN observed was higher than would be expected for the general population at risk. The observed-to-expected ratios (OER) for all SMN, aero-upper-digestive SMN and non-aero-upper-digestive SMNs were 1.73, 5.53, and 0.62, respectively. Overall 5- and 10-year survivals were 76% and 57%, respectively, for those who did not develop SMN, as compared with 68% and 26%, for those who developed SMN (P = .003). Overall, 13 patients (8.2%) have died from laryngeal cancer, while 23 (15%) died from SMN (P = .001). CONCLUSION: This study confirms a higher incidence of SMN in T1 glottic cancer patients, compared with the general population. The majority of cases occur in aero-upper-digestive sites. These patients are more likely to die from their SMN than from glottic cancer. Patients with T1 squamous cell carcinoma of the glottic larynx represent a group of head and neck cancer patients who should be targeted in studies evaluating the potential benefits of chemoprevention, and aggressively counseled for social and/or behavioral modifications.

Carcinoma, Squamous Cell↗
PubMed1998

A randomized trial of endoscopy vs no endoscopy in the management of seronegative Helicobacter pylori dyspepsia.

BACKGROUND: It is unclear whether endoscopy influences the management of Helicobacter pylori negative dyspepsia. AIM: To determine whether endoscopy alters health-care resource utilization, quality of life and symptom outcome in H. pylori seronegative dyspeptic patients aged under 45 years; and to determine which factors predict outcome of symptoms. METHOD: One hundred and fifty-four H. pylori seronegative subjects were randomized to have an endoscopy or no endoscopy before subsequent management by their GPs. Assessment was carried out at 6 months and supplementary information obtained at 12 months. RESULTS: There was no significant difference between the two groups for progression of dyspeptic symptoms (better, same and worse) at 6 months (47%, 46%, 7% vs 43%, 52%, 5%), and at 12 months (55%, 34%, 11% vs 57%, 28%, 15%). Prescriptions were lower in both groups at 6 and 12 months than on entry into the study, independent of endoscopy. Endoscopy did not influence quality of life, visits to GPs and days lost from work. Prognostic factors for symptom resolution at 6 months were lower severity of initial symptoms, non-smoking, non-Caucasians, less anxious patients and those not on acid suppressants. CONCLUSIONS: H. pylori negative dyspeptic patients aged under 45 years without sinister symptoms could be managed without the need of an endoscopy.

Adolescent↗
PubMed1998

Importance of ribosomal frameshifting for human immunodeficiency virus type 1 particle assembly and replication.

The recent development and use of protease inhibitors have demonstrated the essential role that combination therapy will play in the treatment of individuals infected with the human immunodeficiency virus type 1 (HIV-1). Past clinical experience suggests that due to the appearance of resistant HIV-1 variants, additional therapeutics will be required in the future. To identify new options for combination therapy, it is of paramount importance to pursue novel targets for drug development. Ribosomal frameshifting is one potential target that has not been fully explored. Data presented here demonstrate that small molecules can stimulate frameshifting, leading to an imbalance in the ratio of Gag to Gag-Pol and inhibiting HIV-1 replication at what appears to be the point of viral particle assembly. Thus, we propose that frameshifting represents a new target for the identification of novel anti-HIV-1 therapeutics.

Animals↗
PubMed1998

Mechanisms of EGF-induced stimulation of sodium reabsorption by alveolar epithelial cells.

We investigated the effects of epidermal growth factor (EGF) on active Na+ absorption by alveolar epithelium. Rat alveolar epithelial cells (AEC) were isolated and cultivated in serum-free medium on tissue culture-treated polycarbonate filters. mRNA for rat epithelial Na+ channel (rENaC) alpha-, beta-, and gamma-subunits and Na+ pump alpha1- and beta1-subunits were detected in day 4 monolayers by Northern analysis and were unchanged in abundance in day 5 monolayers in the absence of EGF. Monolayers cultivated in the presence of EGF (20 ng/ml) for 24 h from day 4 to day 5 showed an increase in both alpha1 and beta1 Na+ pump subunit mRNA but no increase in rENaC subunit mRNA. EGF-treated monolayers showed parallel increases in Na+ pump alpha1- and beta1-subunit protein by immunoblot relative to untreated monolayers. Fixed AEC monolayers demonstrated predominantly membrane-associated immunofluorescent labeling with anti-Na+ pump alpha1- and beta1-subunit antibodies, with increased intensity of cell labeling for both subunits seen at 24 h following exposure to EGF. These changes in Na+ pump mRNA and protein preceded a delayed (>12 h) increase in short-current circuit (measure of active transepithelial Na+ transport) across monolayers treated with EGF compared with untreated monolayers. We conclude that EGF increases active Na+ resorption across AEC monolayers primarily via direct effects on Na+ pump subunit mRNA expression and protein synthesis, leading to increased numbers of functional Na+ pumps in the basolateral membranes.

Animals↗
PubMed1998

Phase II trial of paclitaxel, fluorouracil, and cisplatin in patients with advanced carcinoma of the esophagus.

PURPOSE: We have previously identified paclitaxel as an active single agent in the treatment of esophageal cancer. We performed a phase II trial of paclitaxel in combination with cisplatin and fluorouracil (5-FU), conventionally used chemotherapy for esophageal cancer. The antitumor response, toxicity, and survival of patients treated with the three-drug regimen were evaluated. PATIENTS AND METHODS: Sixty-one patients with advanced, surgically unresectable, or metastatic squamous cell or adenocarcinoma of the esophagus were treated. No prior chemotherapy was allowed. Thirty patients had adenocarcinoma and 31 patients had squamous cell carcinoma. The majority (47 patients; 77%) had metastatic disease and 14 patients (23%) had an unresectable primary or locally recurrent tumor. Patients received paclitaxel 175 mg/m2 by 3-hour infusion day 1; cisplatin 20 mg/m2 daily days 1 through 5, and 5-FU by continuous infusion at a dose of 1,000 mg/m2 daily days 1 through 5. Because of toxicity observed in the first 10 patients treated, the starting dose of 5-FU was subsequently reduced to 750 mg/m2 daily in the remaining patients. A planned attenuation of cisplatin to 15 mg/m2 daily was made after the first three cycles. Granulocyte colony-stimulating factor (G-CSF) was not routinely administered unless the patient had an episode of febrile neutropenia or prolonged grade 4 neutropenia. Treatment was recycled every 28 days. RESULTS: Sixty-one patients completed a median of five cycles, and 60 patients were assessable for response. Major responses were seen in 29 patients (48%; 95% confidence intervals, 35 to 61), which included seven complete responses (12%). Comparable response rates were seen for patients with adenocarcinoma (46%) and those with squamous carcinoma (50%), and for patients with metastatic disease (22 of 46 patients; 48%) and those with locally advanced disease (seven of 14 patients; 50%). A significantly higher complete response rate was observed in patients with squamous carcinoma (20%) compared with those with adenocarcinoma (3%; chi2 P=.04). The median duration of response was 5.7 months (range, 1 to 18.6 months). Median survival was 10.8 months (range, 1.5 to 25 months). Toxicity was severe but manageable with dose attenuation, and included 18% of patients with grade 3 neurologic toxicity. Twenty-eight patients (46%) required a dose attenuation for toxicity, and 42 of 275 treatment cycles (15%) required a dose attenuation. Twenty-nine patients (48%) required hospitalization for toxicity, which included 11 patients for neutropenic fever (18%). There were no treatment-related deaths. CONCLUSION: The combination of paclitaxel, cisplatin, and 5-FU has substantial antitumor activity in metastatic esophageal carcinoma, with a remarkable complete response rate noted in patients with squamous carcinoma. Paclitaxel is an important new agent in the treatment of esophageal carcinoma, and further evaluation of this agent in combination chemotherapy is warranted. Given the toxicity associated with the current regimen, the optimal dose and schedule of paclitaxel in combination chemotherapy remain to be established.

Adenocarcinoma↗
PubMed1998

In vitro and in vivo comparison of the low-resistance Groningen and the Provox tracheosophageal voice prostheses.

This study has been performed to evaluate and compare two frequently used indwelling tracheoesophageal voice prostheses, the low-resistance (LR) Groningen and the Provox voice prosthesis. The airflow resistance in vitro of the Provox prosthesis has been measured and compared to our reported results of the LR Groningen prosthesis. The in vivo study involved fifteen non-myotomized laryngectomees who randomly received one of the two prostheses. Measurements were performed of the intratracheal phonatory pressure and of voice parameters. The intelligibility of speech in noise was evaluated in eight patients. Patients preferences regarding the two prostheses were assessed. Aerodynamic measurements show the Provox voice prosthesis to have a lower airflow resistance. The median intratracheal phonatory pressure for phonation of 75 dB was significantly lower (2.1 kPa) in patients using the Provox voice prosthesis. Speech rate, maximal phonation time and maximal vocal intensity showed no significant difference. The intelligibility of speech in noise produced with the Provox was significantly better than the speech produced with the LR Groningen prosthesis. Subjectively, most patients preferred the Provox prosthesis because speech required less effort. Patients with a hypotonic pharyngoesophageal segment tended to prefer the LR Groningen prosthesis.

Adult↗
PubMed1998

Natural history and prognostic factors for survival in patients with acquired immune deficiency syndrome (AIDS)-related primary central nervous system lymphoma (PCNSL).

The incidence of primary central nervous system lymphoma (PCNSL) is increasing rapidly. It will be the most common primary malignant neoplasm of the brain by the year 2000. PCNSL is an important lethal complication in acquired immunodeficiency syndrome (AIDS) patients. Our objective was to study the natural history and prognostic factors for survival in patients with AIDS-related PCNSL. This is a retrospective cohort study of 75 patients with the diagnosis of AIDS-related PCNSL followed at Jackson Memorial Hospital/University of Miami. Medical records were abstracted for information about age, gender, race, and ethnicity. The method of diagnosis, treatment, and outcome of AIDS and PCNSL in this group were examined. Univariate and multivariate analyses were performed to identify prognostic factors for survival. The median age was 37 years. Males comprised 84% of the patients and 55% of the patients were Hispanic. The most common human immunodeficiency virus (HIV) risk factors were homosexuality and multiple sexual partners. The median cluster designation (CD) 4 count was 15/microl and the median lactic dehydrogensase (LDH) was 1.5x normal. Computed-assisted tomographic (CT) scans of the brain showed multiple lesions in 44% of the patients. Single-photon emission CT scan (SPECT) Thallium-201 of the brain was performed in two-thirds of patients. The most common histologies were immunoblastic and large cell lymphoma. Cranial radiation was given to 72% of the patients, and 55% of them did not complete treatment. The median survival of the group was 1.3 months. Univariate and multivariate analysis showed that longer survival was associated with good performance status (ECOG = 1 to 2 vs. 3 to 4). The presence of prior opportunistic infections, risk factors for AIDS, CD4 counts, level of LDH, ethnicity, gender, duration of symptoms before diagnosis, and race did not influence survival. PCNSL is a neoplasm with a very poor prognosis and short survival even with CNS radiation therapy. Performance status appears to be the main prognostic factor for survival. No significant differences in presentation or outcome were detected between the Hispanic and non-Hispanic patients.

Adult↗