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Biomedical subjects

L E Davis

Publications and source records attributed to L E Davis.

At least 163 records · Page 9Linked to original sources
PubMed1984

Use of dextran and post-primary antibody fixation in immunoperoxidase staining of fresh frozen tissue. Detection of immunoglobulin associated with squamous carcinomas of the head and neck.

Use of unfixed fresh frozen tissue sections for immunocytochemical studies reduces the possibility of denaturation of antigenic determinants compared to formalin fixation and paraffin embedding procedures. However, tissue and cellular morphology can be extensively altered in the numerous application and washing steps with frozen tissue sections. We tested a number of buffer solutions and showed that the use of dextran-containing buffers and fixation by glutaraldehyde after primary antibody application preserves tissue morphology. The procedures described here are also applicable to ascertaining the presence of Fc receptors of leukocytes in sections of carcinoma tissues. The buffered dextran washes and post-primary antibody fixation method was used to demonstrate the presence of immunoglobulin associated with squamous carcinoma cells. The immunoglobulin was not removed by washing of tissue sections at 37 degrees C but could be removed by low or high pH buffer washes, suggesting that the immunoglobulin is bound in a specific manner.

Antibodies, Neoplasm↗
PubMed1984

Efficacy of ethylenediamine dihydriodide as an agent to prevent experimentally induced bovine foot rot.

Ethylenediamine dihydriodide (EDDI) was administered by capsule and as a feed premix to cattle in 2 studies. In study I (32 steers), EDDI was given at 0, 12.5, 50, and 200 mg/animal each day and in study II (36 steers) at 0, 30, and 200 mg/animal each day. Serum iodine levels were monitored during the studies. The cattle were inoculated intradermally in the interdigital space with a mixture of Fusobacterium necrophorum and Bacteroides melaninogenicus to induce acute foot rot at day 15 (study I) or day 28 (study II) after EDDI administration was started. Lesions and lameness were evaluated 5 days after challenge exposure, using a subjective scoring system. The cattle receiving EDDI had significantly less severe lesions and lameness than control cattle in both studies (study I, P less than 0.003; study II, P less than 0.001). The results indicated that EDDI was efficacious in prevention of foot rot. The studies demonstrated a direct relationship between dosage levels of EDDI and serum iodine levels. However, at the large dosage level (200 mg) there were some individuals that showed an inability to metabolize and excrete the iodine as demonstrated by high serum iodine levels (600 to 700 micrograms of iodine/dl of serum).

Animals↗
PubMed1984

Efficacy of ethylenediamine dihydriodide in the prevention of naturally occurring foot rot in cattle.

The efficacy of an ethylenediamine dihydriodide containing salt mixture was evaluated with regard to the prevention of naturally occurring foot rot in pastured cattle. Ninety-six cattle were assigned to the treatment group and 96 were assigned to the control group. The groups were allowed consumption of salt-mineral mixtures, ad libitum, that were identical, except with respect to iodine concentration. The control group's mixture contained 0.0025% iodine and the treatment group's mixture contained 0.125% iodine (0.156% ethylenediamine dihydriodide). The incidence of foot rot was measured, as was the severity of the lesions and accompanying lameness. The incidence of foot rot in the control group (20.8%) was significantly (P less than 0.05) greater than the incidence in the treatment group (8.3%). The severity of foot rot was greater (P = 0.024) in the control calves vs the treatment calves. Total serum iodine concentrations were measured in the 2 groups on days 0, 46, and 130 of the experiment. The serum iodine values of the treatment group on day 46 (46 +/- 19.8 g/dl) and day 130 (23 +/- 12.3 g/dl) were significantly different (P less than 0.01) than the serum iodine concentrations of the control animals and the pretreatment values (day 0) of both groups. Production was measured via calf weaning weights. There were no detectable differences between the 205-day adjusted weaning weights of the calves in the control group vs the calves in the treatment group. Clinical signs of iodism were not observed in the cattle involved in this study.

Animals↗
PubMed1984

Hyperglycemia and hypoinsulinemia during xylazine-ketamine anesthesia in Thoroughbred horses.

Plasma glucose and serum insulin concentrations in Thoroughbreds administered xylazine hydrochloride (1.1 mg/kg; IV) and ketamine hydrochloride (2.2 mg/kg; IV) at dosages sufficient to induce short periods of recumbency and anesthesia were measured. Samples of blood were collected from 6 adult horses before, during, and after the anesthetic period. Plasma glucose (mg/dl) was significantly increased above control (-30 minute concentration) from 15 to 150 minutes after xylazine administration with the peak value occurring at 30 minutes. Serum insulin (microU/ml) was significantly decreased from control from 5 to 90 minutes after xylazine administration, with the nadir occurring at 15 minutes. The alterations in plasma glucose and serum insulin concentrations in xylazine-ketamine-anesthetized horses were similar to the changes in xylazine-sedated horses.

Anesthesia↗
PubMed1984

Antisera specificities to 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide adducts of proteins.

Animals were immunized with either 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI)-coupled peptide hapten-protein carrier conjugates or with N-acylurea EDCI derived protein carrier. Sera from all animals demonstrated antibody to N-acylurea EDCI when tested by double immunodiffusion using N-acylurea EDCI coupled to a heterologous carrier. Two rabbit antisera, one produced to EDCI-coupled peptide-24-thyroglobulin and another produced to N-acylurea EDCI derived thyroglobulin were further characterized using an enzyme-linked immunosorbent assay (ELISA). Competitive binding assays using either EDCI-coupled peptide-protein conjugates or N-acylurea EDCI derived proteins demonstrated the presence of N-acylurea EDCI reactive antibodies. Such antibodies were also shown to react with the EDCI isourea employed as inhibitor. The specificity of the anti-EDCI antibodies to portions of the EDCI molecule was demonstrated using structural analogues of EDCI. Both 3-dimethylaminopropylamine and 2-dimethylaminoethanol effectively inhibited anti-N-acylurea EDCI reactivity. These results show that when EDCI is used as a coupling agent, antibody is produced to N-acylurea EDCI-carrier, the antibody being primarily directed to the 3-dimethylaminopropyl end of the EDCI molecule.

Animals↗
PubMed1983

Relapsing herpes simplex encephalitis following antiviral therapy.

Although treatment for herpes simplex virus (HSV) encephalitis with antiviral agents has improved survival, occasional patients experience unexplained clinical exacerbations. This report presents evidence that some relapses may occur from recurrent viral encephalitis. An adult male developed the classic symptoms of HSV encephalitis. The cerebrospinal fluid (CSF), electroencephalogram, and isotope brain scan suggested a localized encephalitis involving the left temporal lobe. The patient was treated for 10 days with high doses of cytosine arabinoside instead of the currently recommended adenine arabinoside. Progression of encephalitis stopped, and clinical recovery occurred. The HSV antibody titer increased eightfold. Fifty-four days after the initial encephalitis, the patient relapsed with a subacute progressive encephalitis involving the same brain area. The CSF demonstrated oligoclonal bands, elevated immunoglobulin G levels (100 mg/dl), and a high HSV antibody titer (1:8,192 by indirect hemagglutination test). From a left temporal lobe biopsy taken 74 days after onset of the initial encephalitis, herpes simplex virus type 1 was isolated. Without renewed antiviral drug therapy, the patient slowly recovered.

Adult↗
PubMed1983

Inner ear pathology associated with Reye's syndrome.

Severe pathological changes were observed in the inner ear tissues of a 2-month-old patient who died of Reye's syndrome after 5 days of hospitalization. In the organ of Corti, the inner hair cells appeared to be more severely damaged than the outer hair cells. Various degrees of degeneration were observed in all non-sensory epithelial cells lining the cochlear duct. In most turns of the cochlear duct, Reissner's membrane was ruptured and/or collapsed onto the organ of Corti. Likewise, both sensory and non-sensory cells of the vestibular end organs were markedly degenerated. These observations suggest that the inner ear tissues are acutely affected in patients with Reye's syndrome, and that the changes may cause impairment of hearing and/or equilibrium in patients who recover.

Acoustic Maculae↗
PubMed1983

Pharmacokinetics of chloramphenicol in non-lactating cattle.

The pharmacokinetics and bioavailability of a formulation of chloramphenicol base in propylene glycol were determined following administration of single intravenous (i.v.) and subcutaneous (s.c.) 50 mg/kg doses of chloramphenicol to six non-lactating Holstein cows. Mean serum concentrations of chloramphenicol following i.v. administration of 50 mg/kg declined rapidly from a peak of greater than 100 micrograms/ml to 6.9 micrograms/ml at 12 h after administration. Serum concentrations were not detectable at 24 h after administration. The curve of serum concentrations vs time was characteristic of a two-compartment open model. Mean i.v. data gave a biological half-life of 4.3 h and a volume of distribution of the central compartment of 0.44 l/kg. Serum concentrations of chloramphenicol following s.c. administration of 50 mg/kg rose slowly to a broad peak near 20 micrograms/ml from 3 to 8 h after administration and then declined. These data were also analysed according to a two-compartment open model. The biological half-life was 4.2 h and the volume of distribution of the central compartment was 0.50 l/kg. Significant adverse reactions, including acute collapse, intravascular haemolysis and haemoglobinuria, were observed in cows when dosed i.v. Cows dosed s.c. exhibited local reactions at injection sites. The disadvantages of administration of 50 mg/kg doses of chloramphenicol base in propylene glycol appear to be significant and may outweight the potential advantages of parenteral use of the drug as presently formulated.

Animals↗
PubMed1983

Disposition of gentamicin in the genital tract of cows.

The distribution of gentamicin (G) in plasma and uterine lumen was studied following intramuscular (i.m.) and intrauterine (i.u.) treatment. A Foley catheter was inserted into one uterine horn and retained in place by inflation of the cuff. This provided a closed system for collection of uterine lumen samples and analysis of the concentration of gentamicin for 6 h following treatment. Four normal cycling and healthy cows in dioestrus were given i.m. injections of 4 mg gentamicin/kg BW and another two were given i.m. injections of 2 mg gentamicin/kg BW gentamicin. The uteri were infused with 50 ml saline containing phenolsulphonphthalein (PSP) indicator. Blood and infused solution (IS) samples were periodically collected during the 6-h period following i.m. administration. Six hours after injection, approximately 183.7 micrograms gentamicin and 39.4 micrograms gentamicin were accumulated in the uterine lumen of cows receiving 4 mg gentamicin/kg BW and 2 mg gentamicin/kg BW, respectively. The amount of gentamicin reaching the blood stream after i.m. administration of 4 mg gentamicin/kg BW was 2.89 times that reached after administration of 2 mg gentamicin/kg BW based on the area under the curve of plots of plasma concentration of gentamicin versus time. Four normal-cycling and healthy cows in dioestrus were given i.u. infusions of gentamicin (225-275 mg) diluted in 50 ml saline containing PSP indicator using a Foley catheter in a closed system. Samples from the IS and blood were collected at various intervals for 6 h after infusion. Following i.u. infusion of gentamicin, an average of 29.4% of the dose was absorbed into the bloodstream. The majority of the dose of gentamicin (70.6%) remained in the uterine lumen throughout the 6-h period.

Absorption↗
PubMed1983

Pharmacokinetic studies of theophylline in cats.

The pharmacokinetics of theophylline were determined in adult cats and the data were fitted to a two-compartment model. Single intravenous and multiple oral doses of aminophylline were used. The mean plasma theophylline half-life (t1/2) following the single intravenous dose was 7.8 h and the mean apparent specific volume of distribution (V'd(area] was 0.46 1/kg. The absorption half-life (t1/2ab) was 0.5 h and the bioavailability was 96% following oral administration. There was excellent agreement between the predicted and observed plasma theophylline concentrations following multiple oral doses.

Animals↗
PubMed1983

Determination of lidocaine concentrations producing therapeutic and toxic effects in dogs.

Lidocaine was infused at a fixed zero-order rate to eight healthy mongrel dogs until tonic extension (n = 5) and cortical seizures (n = 7) were produced. Lidocaine concentrations determined at 5-min intervals were used to calculate concentrations at which these effects occurred. The tonic extension phase occurred at a mean lidocaine concentration of 8.21 +/- 1.69 micrograms/ml. After a 1-month rest period, the same dogs were anaesthetized and ventricular tachycardia was produced by administering ouabain. Lidocaine was again infused at a fixed zero-order rate until all beats of ventricular origin were abolished. This occurred at a mean lidocaine concentration of 6.25 +/- 1.49 micrograms/ml.

Animals↗
PubMed1983

Pharmacokinetics of digoxin in cattle.

Digoxin was administered as a single intravenous injection of 22 micrograms/kg to six cattle. The resulting serum concentrations were fitted by both a bi- and tri-exponential equation with the latter providing the best fit to the data of a majority of the animals. The biological half-life of digoxin in cattle was found to be 7.8 h. This relatively short half-life in comparison to other animal species dictates that digoxin should be administered more frequently to cattle to provide therapeutic concentrations in serum without broad fluctuations in serum concentrations. Computer simulations of various intravenous dosage regimens suggested that a loading dose of 22 micrograms/kg followed by an infusion of 0.86 micrograms/kg/h would offer the greatest safety and efficacy in bovine patients.

Animals↗
PubMed1983

Pharmacokinetics of lidocaine and its active metabolites in dogs.

The pharmacokinetics of lidocaine in dogs were investigated following the intravenous and intramuscular administration of single doses of lidocaine hydrochloride. The mean elimination rate constant and the mean specific clearance determined for the intravenous portion of the study were 0.786 h-1 and 2.40 1/kg/h, respectively. Following intramuscular administration the mean absorption rate constant was 7.74 h-1. Absorption was nearly complete as the percentage of an intramuscular dose absorbed averaged 91.9%. Concentrations of two N-deethylated metabolites, determined following the administration of lidocaine suggest that monoethylglycinexylidide is eliminated rapidly while glycinexylidide is more slowly eliminated. The relative contribution of these metabolites to the therapeutic and toxic effects of lidocaine and the potential for glycinexylidide accumulation during lidocaine administration remain to be investigated.

Animals↗
PubMed1983

Immunological and microbiological studies of midtrimester amniotic fluid.

Midtrimester amniotic fluids (MAF) from 73 women undergoing an amniocentesis were studied. The mean immunoglobin G (IgG) level was 34 +/- 14 mg/dl, which is higher than that reported in the third trimester. The maternal serum:MAF IgG ratio was 29 suggesting the blood:MAF barrier is less restrictive than others like the blood:cerebrospinal fluid barrier. Antibodies to herpes simplex virus (HSV) type 1 were detected in 78% of the MAF and the maternal serum:MAF HSV antibody titer ratio was 33. Antibodies to cytomegalovirus (CMV) were found in 84% of the MAF and the maternal serum:MAF CMV antibody titer ration was 40. Whenever either antibody was detected in the maternal serum it was also found in the MAF. No viruses, bacteria, mycoplasma, fungi and chlamyidae were isolated from MAF.

Amniotic Fluid↗
PubMed1983

Experimental influenza B virus toxicity in mice. A possible model for Reye's syndrome.

Mice intravenously injected with concentrated infectious influenza B/Lee/40 virus (LD50 = 6400 hemagglutinin units) developed lethargy, seizures, coma, and death 1 to 3 days later. The cerebrospinal fluid cell count was normal. Serum glutamic oxaloacetic transaminase levels increased 19-fold and plasma ammonia levels elevated 2.6-fold over control values. Serum bilirubin levels remained normal. Microvesicular fatty metamorphosis developed in the liver, whereas the brain showed mild cerebral edema without inflammatory changes. Viral propagation did not occur in liver or brain, but viral hemagglutinin, neuraminidase, and probably nucleoprotein antigens were produced in hepatocytes. Many of the clinical, biochemical, and pathologic features of the mouse illness are similar to those seen in Reye's syndrome.

Animals↗
PubMed1983

CT-guided aspiration of a cysticercotic thalamic cyst.

Removal of either parenchymal or intraventricular cysts in neurocysticercosis has traditionally necessitated operative intervention with its concomitant morbidity and mortality (L. Stepien and J. Chorobski, Arch Neurol Psychiat Chicago 1949;61:499-527; L. Stepien, J. Neurosurg 1962;19:505-13). To our knowledge, percutaneous parenchymal cyst aspiration to reduce mass effect has not been previously reported. We describe a case of successful CT-guided percutaneous thalamic cyst puncture and aspiration to reduce both obstructive hydrocephalus and raised intracranial pressure.

Contrast Media↗