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Biomedical subjects

J W McBride

Publications and source records attributed to J W McBride.

At least 19 recordsLinked to original sources
PubMed1996

Characterization of bovine pulmonary and serum antibody responses after parenteral or intrapulmonary vaccination with live Pasteurella haemolytica.

Pulmonary and serum antibody responses were evaluated in eight calves vaccinated [four intrapulmonary-right diaphragmatic lobe (IP) and four subcutaneous (SC)] with Pasteurella haemolytica A1 (Ph-1) impregnated agar beads and eight respective sham-vaccinated calves. Experimental and sham groups were challenged in both diaphragmatic lobes with Ph-1 34-37 d after vaccination (DAV) and necropsied 6 d after challenge (DAC; 40-43 DAV). IgG antibodies contained in fluids from the diaphragmatic lobes of vaccinated calves had different patterns of antigen specificity compared with IgG antibodies in analogous sera. Using ELISA, anti-Ph-1 IgA and IgG antibody concentrations were significantly higher (P < 0.05) in lung lavage fluids from the IP group before and after challenge compared to the SC and sham groups. The IP and SC groups developed IgA, IgG and IgM antibody titers in nonvaccinated lung lobes after vaccination and challenge. The IP and SC groups exhibited significantly (P < 0.05) smaller pulmonary lesions than the sham groups and pulmonary IgG and IgA antibodies were associated with increased protection.

Animals↗
PubMed1996

PCR detection of acute Ehrlichia canis infection in dogs.

A polymerase chain reaction (PCR)-based detection assay that specifically detected Ehrlichia canis in dogs with acute infections was developed. A region of the 16S ribosomal RNA gene of E. canis was targeted for PCR amplification and chemiluminescent hybridization (CH) with a complementary internal 287-base pair (bp) oligonucleotide probe. The CH improved the PCR assay sensitivity 1,000-fold as compared with visualization on ethidium bromide-stained agarose gels. The PCR assay with CH (PCR/CH) detected as little as 30 fg of E. canis genomic DNA, the equivalent of approximately 150 E. canis organisms. The 495-bp product defined by the specific primers was not detected when genomic DNA from E. platys, E. chaffeensis, E. risticii, and E. equi were used in the PCR/CH assay. The PCR/CH assay was tested with unfractionated blood samples collected from 9 dogs experimentally infected with E. canis. The PCR/CH assay had greater detection sensitivity than did cell culture isolation (CCI) from infected blood. PCR/CH detected E. canis 7 days prior to CCI in 4 of 6 experimentally infected dogs. The results obtained with the PCR/CH assay otherwise consistently matched the results obtained by CCI. This PCR/CH assay is a rapid, sensitive, and specific method for E. canis detection with sensitivity comparable to or exceeding that of CCI. A diagnosis of E. canis using this PCR/CH assay can be made in 2 days as compared with 1-4 weeks for CCI. The PCR/CH assay appears to be an acceptable alternative or complement to current diagnostic techniques.

Animals↗
PubMed1995

Development of polymerase chain reaction for specific identification of epizootic hemorrhagic disease virus serotype 1.

The diagnostic potential of the polymerase chain reaction (PCR) for specific identification of epizootic hemorrhagic disease virus serotype 1 (EHDV-1) in cell culture and clinical specimens was evaluated. Using oligonucleotide primers, selected from genome segment 2 of EHDV-1 (New Jersey strain), the PCR-based assay resulted in a 862 base pair (bp) PCR product. EHDV-1 RNA from United States prototype serotype 1 and a number of EHDV-1 field isolates, propagated in cell cultures, were detected by this PCR based assay. The specific 862 bp PCR products were visualized on ethidium bromide-stained agarose gel. Identity of the PCR product was confirmed by chemiluminescent hybridization with non radiolabelled internal probe. Using chemiluminescent hybridization, the sensitivity of the PCR assay was 1.0 fg of virus RNA (equivalent to 60 virus particles). Amplification product was not detected when the PCR-based assay was applied to RNA from EHDV serotype 2 (EHDV-2); the United States bluetongue virus (BLU) prototypes serotypes 2, 10, 11, 13, and 17; total nucleic acid extracts from uninfected BHK-21 cell; or blood cells from calves and deer that were EHDV-seronegative and virus isolation negative. Application of this EHDV-1 PCR-based assay to clinical samples resulted in detection of EHDV-1 RNA from blood samples, collected from a calf experimentally infected with EHDV-1. The described PCR-based assay provides a simple, rapid, sensitive, specific and inexpensive method for specific identification of EHDV-1 infection in susceptible ruminants.

Animals↗
PubMed1993

Detection of antigenemia by enzyme-linked immunosorbent assay in horses with experimental Ehrlichia risticii infection.

Four horses were inoculated with Ehrlichia risticii contained in either infected murine P388 D1 cells or heparinized blood from an infected horse. All 4 horses produced serum antibody, plasma antigen, and clinical signs of the disease. An enzyme-linked immunosorbent assay was used to detect antibody in the serum and was also used in conjunction with an anti-E. risticii monoclonal antibody to detect antigenemia. These laboratory and clinical findings were correlated to determine the efficiency of the antigen detection method for discerning E. risticii infection.

Animals↗
PubMed1993

Detection of humoral antigen and antibody by enzyme-linked immunosorbent assay in horses with experimentally induced Ehrlichia equi infection.

An enzyme-linked immunosorbent assay (ELISA) was used to detect antigen in plasma and antibody in serum of 3 horses inoculated with Ehrlichia equi. Clinical signs, including rectal temperature, were correlated with the antigen and antibody detection. ELISA was very efficient in detection of serum antibody. Antigen detection using monoclonal antibodies to E. equi and ELISA should be considered as a diagnostic method.

Animals↗
PubMed1992

Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica after intrapulmonary inoculation.

Systemic and pulmonary antibody responses of calves to Pasteurella haemolytica were evaluated by measuring immunoglobulin production in blood for 9 days and in pulmonary lavage fluid for 7 days after intrapulmonary inoculation. Clinical signs, pulmonary lesions, pulmonary and systemic inflammatory response, and amount of antigen in lavage fluid were used to evaluate the response of calves to challenge with P haemolytica. The pulmonary response consisted of production of IgG, IgE, and IgM antibodies to P haemolytica antigens and a 17- to 68-fold increase of cells in lavage fluid 8 hours after inoculation, with a gradual decrease toward normal. Antibodies of the IgM isotype to P haemolytica were demonstrated as early as 8 hours through 7 days after inoculation in 3 of 3 calves. Of the anti-P haemolytica isotypes, IgM was found in the highest concentration. In all of the inoculated calves, IgE was found 1 to 2 days after inoculation, and IgG was found in 2 of 3 inoculated calves from day 1 through 7 after inoculation. Detection of IgG correlated with smaller pulmonary lesions. Immunoglobulin A was not detected in lavage fluid. Serum was evaluated for IgG and IgM antibody response to P haemolytica. Specific IgM was detectable 5 days after inoculation, and IgG was detectable 7 days after inoculation. Pasteurella haemolytica antigens were not detected in serum or plasma. A transient increase in neutrophil count was found 8 hours after inoculation, with return to baseline values by 24 hours after inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Use of an indwelling bronchial catheter model of bovine pneumonic pasteurellosis for evaluation of therapeutic efficacy of various compounds.

A model of bovine pneumonic pasteurellosis, using an indwelling bronchial catheter for inoculation and subsequent lavage of a single main stem bronchus of the lung, was evaluated in a preliminary efficacy trial of an experimental therapeutic compound. Inoculation of 10(7) Pasteurella haemolytica organisms into the bronchus consistently induced a focal pneumonic lesion with typical morphology of pneumonic pasteurellosis in the left or right caudal lung lobe. The experimental treatment caused significant (P less than 0.05) reduction in lung lesion volume, compared with that of a saline-treated control. It also caused significant (P less than 0.05) reduction in lavage fluid bacterial counts at 48 hours after inoculation, compared with counts in the controls. The inflammatory cell count and the percentage of neutrophils increased markedly in lavage fluids 8 hours after inoculation, but differences were not detected between treatments. Significant differences between treatments were not found in clinical signs, rectal temperature, or histologic changes. This model appears to be a sensitive indicator of treatment efficacy and has the advantage over previous models of pneumonic pasteurellosis of allowing sequential monitoring of the primary lesion site.

Animals↗
PubMed1988

Supraventricular tachycardia treated with continuous infusions of propranolol.

Because oral therapy is often contraindicated in hospitalized patients we assessed the safety and efficacy of continuous intravenous propranolol infusions in nine patients with refractory supraventricular tachycardia. Standard pharmacokinetic formulas predicted a loading dose (52.2 +/- 38.3 micrograms/kg), steady-state plasma concentration, and the initial maintenance dose (16.1 +/- 16.2 micrograms/kg/hr; range 6.1 to 56.0 micrograms/kg/hr) to control heart rate. Subsequent maintenance doses (3.9 to 74.9 micrograms/kg/hr) were determined by clinical response. Heart rate decreased from 146 +/- 22 to 98 +/- 16 beats/min (p less than 0.0001). This decrease persisted throughout the infusion. Measured propranolol levels (28 +/- 21 ng/ml) did not differ significantly from the predicted levels (23 +/- 17 ng/ml). The duration of the infusion averaged 97 +/- 77 hours. A side effect, transient wheezing, occurred in only one patient. This resolved when the infusion rate was decreased. We conclude that continuous propranolol infusions appear safe and effective in treating these patients with supraventricular tachycardia.

Adult↗
PubMed1986

Is serum creatine kinase-MB in electrically injured patients predictive of myocardial injury?

We undertook a retrospective study of 36 victims of high-voltage electrical contact injuries to determine the incidence and possible source of elevated creatine kinase (CK)-MB enzyme in their serum. Only two sustained myocardial infarctions (one late) according to history, electrocardiographic findings, and clinical course. Serum lactate dehydrogenase isoenzyme levels were abnormal but revealed no myocardial infarction patterns. Creatine kinase total activity, however, reached 1.5 to 1,140 times normal in 92% and the CK-MB level was abnormal in 50% despite the low incidence of myocardial damage. Skeletal muscle CK and CK-MB levels in four nonelectrically injured patients were comparable to those in normal muscle while CK and CK-MB activity was elevated in six such electrical injuries. There was a gradient in CK-MB activity with greatest CK-MB activity in "normal" muscle near the injury site, lesser amounts in border tissue, and least in the worst-injured site. We conclude that myocardial injury is uncommon in high-voltage electrical injury and skeletal muscle injured by high electrical voltage is stimulated to produce, as well as release, CK-MB.

Adolescent↗
PubMed1986

Esophageal gastric tube airway vs endotracheal tube in prehospital cardiopulmonary arrest.

We evaluated the efficacy of the esophageal airway (EA) by prospectively randomizing 175 prehospital cardiopulmonary arrest patients to receive either an esophageal gastric tube airway (EGTA) or an endotracheal tube (ET). If attempts with the initial airway failed, the alternate airway was attempted. The cost of training paramedics in EA use was considerably less than the ET ($80 vs $1,000). Survival to the emergency room, to hospitalization and to discharge in ET and EGTA groups were 64.4 percent, 25.6 percent, 11.1 percent, and 54.1 percent, 27.1 percent, 12.9 percent, respectively--differences not statistically significant. The incidence of neurologic residual (ET 50 percent, EGTA 36.4 percent) and congestive heart failure (ET 40 percent, EGTA 45.5 percent) in surviving ET and EGTA patients did not differ (NS). An additional 125 consecutive patients with only the opportunity to receive an EA were also evaluated and did not differ in mortality, neurologic residual, or congestive heart failure from ET patients. We conclude that the EA is a satisfactory alternative to the ET for short-term prehospital use in cardiopulmonary arrest patients.

Aged↗
PubMed1982

Variable first-pass elimination of propranolol following single and multiple oral doses in hypertensive patients.

The disposition of orally administered propranolol has been studied in twelve patients with mild to moderate hypertension. Each patient received single doses of 40, 80, and 160 mg. Serial blood samples were obtained and quantitated using a sensitive gas chromatographic analytical technique. Ten of the twelve patients received 40 mg doses of propranolol every 6 hours for 5 doses. Blood samples were obtained after administration of the first, second, third, and fifth doses. Substantial intersubject variability in the areas under the bloodconcentration-time profiles (AUC) was observed. Evidence for a nonlinear first-pass effect was not obtained in all patients. The patients displaying a nonlinear relationship between dose and AUC for single propranolol doses consistently showed a similar relationship during multiple dosing. Blood levels obtained following the evening dose (08h00 to 14h00) appeared to be lower than expected based on multiple-dosing pharmacokinetic principles. These findings suggest that monitoring propranolol blood levels is the most viable way to ascertain therapeutic concentrations of this drug.

Administration, Oral↗