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Biomedical subjects

J M Byers

Publications and source records attributed to J M Byers.

At least 19 recordsLinked to original sources
PubMed1995

Changes in brainstem calcitonin gene-related peptide after VIIth and VIIIth cranial nerve lesions in guinea pig.

The present study investigated the effect of seventh and eight cranial nerve lesions on the prominence of calcitonin gene-related peptide in the hypoglossal (XII), facial (VII), abducens (VI), and oculomotor (III) cranial nerve nuclei. Guinea pigs were anesthetized and subjected to unilateral cochlear removal, vestibular end organ ablation, and seventh nerve transection. After a survival period ranging from 4 h to 5 days, each animal was anesthetized and perfused intracardially. Frozen sections were collected through the brainstem and stained immunohistochemically for calcitonin gene-related peptide using a polyclonal antibody with the Vectastain ABC kit and protocol. Positive cells were counted in each nucleus bilaterally and analyzed for side to side differences. Nuclei XII and III showed no significant difference in the numbers of cells staining positively for calcitonin gene-related peptide between the ipsilateral and the contralateral sides to the lesion. However, nuclei VII and VI showed elevated numbers ipsilateral to the lesion on some days, but not all. For VII, there was no significant difference before 24 h, but there were significant differences 1-5 days after the lesion. Similarly, in VI, there was no difference before 24 h, but differences were significant beginning with day 1 and continuing through day 3, and finally disappearing by day 4. Changes in the numbers of CGRP positive cells in VII measurable 24 h after the lesion and continuing for at least 5 days afterward indicate a central nervous system retrograde response to peripheral motor nerve injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Abducens Nerve↗
PubMed1995

Pathology consultation services via the Arizona-International Telemedicine Network.

The Arizona-International Telemedicine Network (AITN) links 4 cities in Arizona and two international sites in China and Mexico, into a telepathology diagnostic network. Established in 1993, the Network provides second opinions on surgical pathology and cytopathology cases. Workstations are 486 PC-based computers. Static images (1024 x 774 x 8 pixels) are grabbed with a variable resolution video camera and sent by 14,400 bit per second modems over ordinary telephone lines. Second opinions are either rendered directly by a general telepathologist or triaged to a specialist. Experience with the first 37 cases indicates a high level of success in providing useful information to referring pathologists over the Network.

Computer Communication Networks↗
PubMed1994

Paranasal sinus infection due to atypical mycobacteria in two patients with AIDS.

Atypical mycobacteria, which are common opportunistic pathogens in patients with AIDS, have not been previously implicated in the pathogenesis of paranasal sinus infections; we describe two such patients. Clinical and radiographic evidence of bilateral maxillary and ethmoid sinusitis was observed for one patient; his infection proved resistant to therapy with conventional antimicrobials and decongestants. Endoscopic ethmoid sinus biopsy yielded a specimen containing acid-fast bacilli (AFB) that were later identified as Mycobacterium kansasii. Antimycobacterial therapy had not resulted in amelioration of the sinusitis > 2 months later, at which time he died of cerebral toxoplasmosis. The second patient presented with a tender right frontotemporal soft-tissue mass; a computed tomogram disclosed that it extended through the frontal bone to the frontal sinus. Inflamed tissue debrided from the sinus contained AFB; cultures first yielded M. kansasii and later Mycobacterium avium complex. Bacteremia due to both organisms was also demonstrated. Infection progressed despite therapy.

AIDS-Related Opportunistic Infections↗
PubMed1992

Repair of parastomal hernias using polypropylene mesh.

Parastomal hernias are a common complication of ostomy construction. We have developed a method of repair that uses two strips of polypropylene prosthetic mesh through a midline incision. The medical records of 19 patients who underwent parastomal hernia repair were retrospectively reviewed. All nine patients operated on for this condition by the senior author (R.G.P.) (group 1) underwent repairs with this technique. All ten patients operated on by other surgeons in our center (group 2) underwent repairs in which the stoma was moved, the fascia was directly repaired through a parastomal incision, or the fascia was repaired via a midline incision. No patients in group 1 had recurrences while five patients in group 2 had recurrences. Neither group developed strictures or stomal prolapse. Our method of repair is technically easy and has excellent results. It is especially suitable in very large hernias in which incisional hernia is likely in the original stoma site if the stoma is moved.

Abdominal Muscles↗
PubMed1989

Rudolf Virchow--father of cellular pathology.

Rudolf Virchow, the famous German physician-scientist-statesman and social activist of nineteenth century Berlin, contributed greatly to the science of pathology by his teaching, research, and publishing. He consolidated the idea of cellular changes as the basis of disease and introduced many modern concepts and terms into medical science. He led in defining orderly, methodical procedures for the autopsy and emphasized its importance to medicine. Virchow's life and work fundamentally influenced and altered modern medical concepts of disease.

Berlin↗
PubMed1987

An analysis of toxic deaths, 1982 to 1985, Pima County, Arizona.

Toxic deaths in Pima County, Arizona, were studied over a four-year period. The deaths were analyzed according to cause and manner of death, toxic substance, and demographic data. The age group 40 to 49 years had the highest rate of suicide from toxic substances. The accident death rate was highest for ages 20 to 29 years. Carbon monoxide was most often found to be the cause of deaths in this study. The most prevalent drugs were narcotics followed by antidepressants, cocaine, and barbiturates. Comparisons are made with similar studies.

Adolescent↗
PubMed1986

Cocaine-related deaths in Pima County, Arizona, 1982-1984.

A three-year review of toxicology data from medical examiner autopsies in Pima County, Arizona, has demonstrated that cocaine has rapidly become a leading substance of abuse, second only to alcohol in the frequency of drugs detected by toxicologic analysis of all suspicious deaths, motor vehicle accident fatalities, homicides, and suicides. Gastric contents and urine were analyzed by thin-layer chromatography, and nasal swabs, blood, and urine were tested for the combination of cocaine and its metabolite benzoylecgonine by quantitative radioimmunoassay. A total of seventy-two deaths in Pima County from 1982 to 1984 have involved cocaine. Seventy percent of these have occurred in the last fifteen months. Marked variation in the individual response to cocaine compared to the blood concentration of cocaine/metabolite was noted.

Adult↗
PubMed1983

Lidocaine elimination: effects of metoprolol and of propranolol.

The effects of administration of metoprolol and propranolol on lidocaine elimination were studied in six healthy young men who did not smoke. Each received three single intravenous doses of lidocaine (2.5 to 3.0 mg/kg injected over 10 min): one alone, one after 1 day pretreatment with propranolol (40 mg orally every 6 hr), and one after 1 day pretreatment with metoprolol (50 mg orally every 6 hr). Lidocaine clearance was 0.88 +/- 0.28 l X hr-1 X kg-1 before beta blockade, 0.61 +/- 0.20 l X hr-1 X kg-1 during metoprolol dosing, and 0.47 +/- 0.16 l X hr-1 X kg-1 during propranolol dosing. There was no correlation between the change in lidocaine elimination and the steady-state concentrations of metoprolol or propranolol, nor between the change in lidocaine clearance and the change in resting heart rate produced by either beta blocker. Metoprolol and propranolol reduce lidocaine elimination significantly.

Adult↗
PubMed1981

Ethanol.

Explore the source record for details and available documents.

Alcoholic Intoxication↗
PubMed1978

A modified ion-selective electrode method for measurement of chloride in sweat.

A modified method of analysis of sweat chloride concentration with an ion-selective electrode is presented. The original method of sweat chloride analysis proposed by the Orion Research Corporation (Cambridge, Massachusetts 02139) is inadequate because it produces erratic and misleading results. The modified method was compared with the reference quantitative method of Gibson and Cooke. In the modified method, individual electrode pads are cut and placed in the electrodes rather than using the pads supplied by the company; pilocarpine nitrate (2,000 mg/l) is used in place of pilocarpine HCl (640 mg/l); sodium bicarbonate as the weak electrolyte is used instead of K2SO4. A 10-minute period for sweat accumulation is employed rather than a zero-time collection as in the original Orion method. The modification has been studied for reproducibility in individuals, reproducibility between right and left arm in individuals; it has been compared extensively with the quantitative method of Gibson and Cooke, both in normal individuals and in patients with cystic fibrosis. There is excellent agreement between the modified method and the quantitative reference method. There appears to be a slight bias toward higher concentrations of chloride from the right arm compared with the left arm, but this difference is not medically significant.

Adolescent↗
PubMed1977

Assay of phenobarbital: adaption of "EMIT" to the centrifugal analyzer.

We have adapted the centrifugal analyzer to the homogeneous enzyme immunoassay ("EMIT") for phenobarbital. The assay was modified to give greater range and sensitivity, and less reagent is needed. The transfer disc is prepared with totally automatic pipetting. Results are calculated with a micro-computer that provides a logit transformation of absorbance data. Precision and accuracy are excellent, and results correlate well with those by gas-liquid chromatography.

Autoanalysis↗
PubMed1976

Immunochemical determination of human immunoglobulins with a centrifugal analyzer.

We used an unmodified centrifugal analyzer (Aminco "Roto-Chem II") to measure human immunoglobulins IgG, IgA, and IgM in diluted sera, with diluted commercial monospecific antisera. Turbidimetric endpoint readings at 340 nm were taken at 4 min for IgG and 12 min for IgA and IgM, although multiple timed-interval readings were printed so that the kinetics of the reaction could be observed. Polyethylene glycol was used to enhance the antigen--antibody reaction. A wide range of concentrations can be measured: for IgG, 0.1--24 g/liter; for IgA and IgM, 50--4000 mg/liter. Correlation with radial immunodiffusion and automated immunoprecipitin techniques was satisfactory. Precision, accuracy, linearity, and sensitivity were quite acceptable. Day-to-day precision ranged from 2.5% to 5.2%, depending on sample concentration. The technique is more precise than radial immunodiffusion, and is rapid, simple, and reliable.

Centrifugation↗
PubMed1975

Acute pulmonary alveolitis in narcotics abuse.

Lungs of 17 narcotic abusers from medical-legal autopsies were studied to determine the pathological basis for regional alterations of ventilation and perfusion. Postmortem pulmonary angiographic and histological techniques demonstrated acute alveolar wall inflammation with exudation of fluid and cells into the alveoli in all eight abusers dying of narcotism and in six of nine dying of other causes. All abusers had extensive focal chronic intersititial inflammatory infiltrates. Vascular obstruction due to foreign material occurred only with intravenous use of oral pharmaceuticals, and then only in the microcirculation. Lungs of ten young adults dying suddenly with no history or evidence of narcotics abuse showed no acute alveolitis or intravascular foreign material. Intravenous narcotics injection produces transient acute alveolar inflammation that may account for respiratory manifestations and death. Permanent injury to the lung parenchyma or larger vessels with the usual forms of narcotic abuse is not common.

Acute Disease↗