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Biomedical subjects

J A Patel

Publications and source records attributed to J A Patel.

At least 37 records · Page 2Linked to original sources
PubMed1995

Influence of cellulose triacetate hemodialyzers on vancomycin pharmacokinetics.

This study was designed to evaluate the pharmacokinetics of vancomycin during hemodialysis with cellulose triacetate (CT) high-flux dialyzers and to assess the influence of membrane surface area on intradialytic clearance. In a randomized crossover fashion, the pharmacokinetics of vancomycin were evaluated during dialysis with the CT 110 and CT 190 membranes. Six hemodialysis patients received 1 g of vancomycin immediately after the completion of a dialysis session, and subsequently, blood samples were obtained over a 5-day study period. On Day 3 subjects were dialyzed with CT 110 or CT 190 membranes. The mean intradialytic clearance of vancomycin was 56.7 +/- 7.5 and 100.70 +/- 10.7 mL/min with the CT 110 and CT 190 membranes, respectively (P < 0.05). Significant rebound in vancomycin serum concentrations occurred after dialysis; this rebound appeared to be complete 3 h postdialysis. On the basis of postrebound concentrations, the apparent percent removal of vancomycin was 23.6 +/- 1.2 and 25.2 +/- 8.6% for CT 110 and CT 190 membranes, respectively (not significant). Vancomycin is significantly cleared during dialysis with cellulose triacetate membranes, and its clearance is dependent on membrane surface area. Although a small supplemental dose of vancomycin could be administered after dialysis to replace drug lost during dialysis, it may be more efficient to give a larger dose of vancomycin after several dialysis periods. The determination of vancomycin removal can be used to estimate vancomycin serum concentrations as well as dosage requirements. This in conjunction with serum concentration monitoring can be used to optimize vancomycin dosing.

Adult↗
PubMed1994

Virus and bacteria enhance histamine production in middle ear fluids of children with acute otitis media.

Histamine levels were measured in 677 middle ear fluid (MEF) samples from 248 children (aged 2 months to 7 years) with acute otitis media (AOM); of these, 116 (47%) had documented viral infection. Histamine content was higher in bacteria-positive than in bacteria-negative MEF samples (P = .007) and higher in samples from patients with viral infection than in those from patients with no viral infection (P = .002). Bacteria and viruses together had an additive effect on histamine content in MEF. Histamine concentration in the initial MEF sample tended to be higher in patients with persistent otitis than in those with good response to treatment (P = .14). Results suggest that viruses, bacteria, or both induce histamine production, which leads to increased inflammation in the middle ear. Antihistaminic drugs may be beneficial. Large, prospective, controlled trials of the effects of antihistamine as an adjunct therapy in bacterial and viral AOM are required before recommendations can be made.

Acute Disease↗
PubMed1994

Preparation of respiratory syncytial virus subgroup A and B antigens for enzyme immunoassay antibody detection.

A simplified method was described for purification of respiratory syncytial virus (RSV) subgroup A and B aimed to be used as antigens in enzyme immunoassay (EIA). The titer of each RSV subgroup and the amount of protein was determined from the visible band in 45% sucrose gradient. The quality of prepared RSV subgroup antigens for EIA was described in terms of the achievable final titer, the amount of protein, and EIA criss-cross titration. The RSV subgroup A and B antigens, diluted as 1:100 (low opalescent band in 45% sucrose layer) or 1:800 (high opalescent band in 45% sucrose layer) produced a positive reaction in EIA criss-cross titration with IgG antibodies from the patient's serum (convalescent phase) diluted as 1:25,600 (for RSV A) and 1:6,400 (for RSV B). This method offers shorter and more simplified steps of viral antigen purification, and provides acceptable quantity and quality of viral antigens appropriate for use in EIA.

Antibodies, Viral↗
PubMed1993

Association of rhinovirus infection with poor bacteriologic outcome of bacterial-viral otitis media.

Viruses--both alone and in combination with bacteria--have been shown to be a cause of acute otitis media (AOM). Moreover, the presence of virus in middle ear fluid (MEF) interferes with the bacteriologic response to antibiotic treatment in AOM. We studied various factors related to the eradication of bacteria from the MEF of infants and children who had AOM associated with a combination of bacteria and viruses. Of 622 cases of AOM diagnosed and treated between 1985 and 1991, 71 were due to such a combination. Bacteria were eradicated from MEF by 2-4 days of antibiotic treatment in 50 (70%) of these 71 cases; in the remaining 21 cases, the originally identified bacteria persisted or a new pathogenic bacterial species was detected after such treatment. These two groups of cases were compared with respect to the patients' age, sex, race, history of recurrent AOM, duration of respiratory symptoms, and compliance; the type of antibiotic treatment administered; the type of pathogenic bacteria and viruses identified in MEF; the presence of single or multiple pathogens; and the laterality of the disease. The only difference noted was in the type(s) of virus found in MEF. The presence of rhinovirus was associated with a higher rate of bacteriologic failure than was that of respiratory syncytial virus, parainfluenza virus, influenza virus, or other viruses. Our data suggest that the bacteriologic response to antibiotic treatment in bacterial-viral AOM may depend in part on the type(s) of virus present in MEF.

Anti-Bacterial Agents↗
PubMed1993

Presence of respiratory syncytial virus genomic sequences in middle ear fluid and its relationship to expression of cytokines and cell adhesion molecules.

The presence of respiratory syncytial virus (RSV) and several cytokines and cell adhesion molecules in middle ear effusions and mucosal tissues was evaluated using polymerase chain reaction. RSV genomic sequences were detected in 23 (52.7%) of 44 middle ear effusions tested. The sequences were detectable at an even higher rate (82.4%) in effusions of children in whom infectious virus was detected in the nasopharynx. All samples with the RSV genome contained the mRNA for interleukin-1 beta and -6 and tumor necrosis factor-alpha. The messages for these cytokines, together with intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1, were detected in human middle ear mucosal organ cultures infected in vitro with RSV. Our results suggest that the enhanced synthesis of proinflammatory cytokines and cell adhesion molecules in the middle ear infected with RSV may contribute to the inflammatory processes in otitis media.

Base Sequence↗
PubMed1993

Synergy of levofloxacin (L-ofloxacin) and oxacillin against quinolone-resistant Staphylococcus aureus, measured by the time-kill method.

The synergistic activity of levofloxacin and oxacillin against levofloxacin-resistant isolates of methicillin-resistant Staphylococcus aureus was tested by the time-kill method. The combination of levofloxacin at 1/4 the MIC for the isolate plus oxacillin at 8 micrograms/ml (< 1/4 the MIC) was synergistic against seven of nine isolates at 8 h, although no significant synergy was demonstrated at 24 h. This combination may prove to be effective against multidrug-resistant methicillin-resistant S. aureus, and further studies are warranted.

Anti-Infective Agents↗
PubMed1992

Effect of viral respiratory tract infection on outcome of acute otitis media.

We prospectively studied 271 infants and children (2 months to 7 years of age) with acute otitis media (AOM) for viral and bacterial causes, outcome at the end of therapy, and frequency of recurrence within 1 month. Comprehensive virologic methods, including viral antigen detection, cell culture, and serologic studies, were used to diagnose viral infection of the respiratory tract, middle ear, or both. Evidence of viral infection was found in 46% (124/271) of patients with AOM. Sixty-six patients (24%) had virus or viral antigen in the middle ear fluid; 50 of these patients (76%) also had bacteria in middle ear fluid, and 16 (24%) had virus alone. More patients with AOM and combined bacterial and viral infection (51%) had persistent otitis (3 to 12 days after institution of antibiotic treatment), compared with those with only bacterial otitis (35%; p = 0.05) or patients with only viral infection (19%; p less than 0.01). Of patients with only viral infection, 4 of 10 with virus in middle ear fluid had persistent otitis, compared with none of 11 patients who had virus only in nasal wash specimens or whose viral infection was diagnosed only by serologic studies. Our data suggest that viruses interact with bacteria and that concurrent viral infection can significantly worsen the clinical course of bacterial AOM. The presence of virus in middle ear fluid may contribute to the pathogenesis and outcome of bacterial AOM. The mechanism of these interactions deserve further investigation.

Amoxicillin↗
PubMed1992

Presence of cytomegalovirus and herpes simplex virus in middle ear fluids from children with acute otitis media.

Twenty-seven (10%) of 271 infants and children with acute otitis media (AOM) were found to be infected with cytomegalovirus (CMV) or herpes simplex virus type 1 (HSV). CMV or HSV, alone or in combination with bacteria or other viruses, was isolated from the middle ear fluid (MEF) of 10 patients. In three cases, CMV alone was isolated from the MEF, and in one case, HSV alone was isolated. One of the CMV cases involved an acute primary or reactivation of CMV infection, with CMV-bacterial otitis and conjunctivitis as major manifestations. One patient with AOM and stomatitis had purulent otitis associated with the presence of HSV in MEF, with no other bacterial or viral pathogens noted in MEF or nasal wash specimens. While most patients with CMV infection were probably asymptomatic excreters at the time of development of AOM, CMV did enter the middle ear. The presence of CMV in MEF was prolonged, and the patients continued to have clinical signs of otitis despite negative bacterial cultures. Among patients with bacterial otitis, a higher proportion of those who had CMV found only in nasal wash specimens had persistent bacteria in MEF, compared with those who were concurrently infected with other viruses (57% vs. 19%; P less than .04). This report is the first to suggest an etiologic role for CMV and HSV in AOM.

Acute Disease↗
PubMed1992

Detection of genomic sequences of respiratory syncytial virus in otitis media with effusion in children.

The reverse transcriptase-polymerase chain reaction and the nested polymerase chain reaction were used for detection of respiratory syncytial virus (RSV) sequences in middle ear effusions collected from children with otitis media. Sequences of RSV were detected in 21 of 34 samples tested. These samples were collected during and/or after natural outbreaks of RSV infection in the community. In those patients from whose nasopharynges RSV was isolated, the viral sequences were highly detectable (75%) in the effusions. These observations suggest RSV as an important factor in the pathogenesis of otitis media with effusion.

Base Sequence↗
PubMed1987

Lidocaine toxicity after maternal pudendal anesthesia in a term infant with fetal distress.

There have been many reports of lidocaine toxicity especially after maternal paracervical block anesthesia. We recently treated a term infant with evidence of fetal distress who presented with symptoms of lidocaine toxicity after maternal pudendal anesthesia. The infant developed apnea and bradycardia soon after birth which responded to mechanical ventilation and epinephrine. A prolonged Q-T interval was noted on day 1 which normalized by day 3. Cord blood was assayed and revealed an elevated lidocaine level. Lidocaine toxicity has been associated with fetal distress secondary to fetal ion trapping in the presence of acidosis. Although good response to supportive therapy occurred in our patient, other methods of therapy such as exchange transfusion and treatment of seizures may be required in some cases. Awareness of this now uncommon syndrome will lead to prompt diagnosis, appropriate work-up, and management.

Adult↗
PubMed1981

Doxylamine: a cause for false-positive gas chromatographic assay for phencyclidine.

A 25-year-old white woman ingested an unknown quantity of doxylamine succinate and flurazepam. Urine immunoassay screen (EMIT-dau) was positive for benzodiazopine and negative for phencyclidine. Subsequent gas chromatographic assay of the urine revealed a markedly positive assay for phencyclidine. Doxylamine was ultimately found to be the cause for the false-positive gas chromatographic assay for phencyclidine.

Adult↗
PubMed1978

Enzyme multiplied immunoassay technique: a review.

A brief review of the various immunoassays is presented before the basic mechanism of the enzyme multiplied immunoassay technique (EMIT) is described. This is followed by a presentation of the specific advantages and disadvantages of this method, as well as its correlation with other methods as applied to qualitative and quantitative determinations of each type of drug for which EMIT technology is available.

Central Nervous System Agents↗
PubMed1975

Pharmacy-based analytical toxicology service.

An analytical toxicology service, which primarily tests specimens for drugs of abuse but also determines blood levels of therapeutic drugs, is described. Analytical methods discussed are the enzyme multiplied immunoassay technique, hemagglutination-inhibition, the free radical assay technique, radioimmunoassay, thin-layer and gas liquid chromatography, and spectrophotometric analysis. A typical scheme for drug analysis is presented.

Chromatography, Gas↗