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Biomedical subjects

C Johnson

Publications and source records attributed to C Johnson.

At least 451 records · Page 25Linked to original sources
PubMed1984

Elevation of molybdenum hydroxylase levels in rabbit liver after ingestion of phthalazine or its hydroxylated metabolite.

Oral administration of phthalazine (50 mg/kg/day) or 1-hydroxyphthalazine (10 mg/kg/day) to female rabbits caused an increase in the specific activity of the hepatic molybdenum hydroxylases aldehyde oxidase and xanthine oxidase, whereas no effect on microsomal cytochrome P-450 activity was observed. The rise in the specific activity of purified aldehyde oxidase fractions was accompanied by a similar increase in molybdenum content. A significant lowering of the Km value for phthalazine was demonstrated with enzyme from treated rabbits whereas Km values for structurally similar substrates such as isoquinoline were unchanged from control values. Iso-electric focusing of DEAE-cellulose fractions showed the presence of an additional band of activity indicating that genuine induction of aldehyde oxidase had occurred in rabbits treated with phthalazine or 1-hydroxyphthalazine.

Aldehyde Oxidase↗
PubMed1984

Use of protein-to-creatinine ratio in a single urine specimen for quantitative estimation of canine proteinuria.

The daily excretion of urinary protein was evaluated in 8 conditioned research dogs and in 10 hospitalized, proteinuric dogs, using 24-hour urine collections. Concurrent with each 24-hour urine collection, a 5- to 10-ml urine specimen was obtained during midday. The ratio of urine protein to urine creatinine concentration was determined from the single urine specimen for each dog. Linear regression analysis was used to calculate the correlation between that ratio and the 24-hour urinary protein loss (mg/kg of body weight). The coefficient of determination was significant (r2 = 0.95, P less than 0.0001). Determination of the protein-to-creatinine ratio in a single urine specimen was found to be a sensitive, rapid, and dependable diagnostic technique for detection and quantitative estimation of proteinuria.

Animals↗
PubMed1984

Characterization of a novel serum albumin-binding glycoprotein secreted by endothelial cells in culture.

A unique and heretofore undescribed glycoprotein with unusual properties has been purified and characterized from the culture medium of endothelial cells. This protein is synthesized constitutively by bovine, porcine, and human endothelial cells, by vascular smooth muscle cells, and by fibroblasts from dermis and ligament. It is also a biosynthetic product of some murine malignant and/or transformed cell lines but was not uniformly observed in cells derived from human neoplasms. The glycoprotein exhibited an apparent molecular weight by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of approximately 39,000 before reduction, and of approximately 43,000 (43K protein) in the presence of dithiothreitol. Amino acid analysis revealed high levels of potentially acidic residues (Asx + Glx = 303 residues/1000) and of cysteine (35 residues/1000). Limited proteolysis indicated that both disulfide bonds and mannosylated sites were distributed throughout the protein chain. Neither phosphate nor sulfate was incorporated into the 43K protein during biosynthetic labeling of endothelial cells. In addition, the 43K protein did not bind to heparin, thrombin, gelatin, or fibronectin and displayed no affinity for [3H]diisopropyl fluorophosphate. In contrast, the 43K protein demonstrated a high affinity binding to bovine serum albumin which was dissociable only by sodium dodecyl sulfate. A complete lack of identity with several prominent serum and platelet proteins and with other mesenchymal cell products was shown by one- and two-dimensional peptide mapping, affinity chromatography, and immunological studies. Immunofluorescence staining of endothelial cells showed a granular distribution for the 43K protein that was typical of a secreted protein. The function of this apparently novel glycoprotein is presently not known. Its synthesis by normal mesenchymal cells and by malignant or transformed cells of both ectodermal and endodermal origin suggests a general role in cell function that is independent of transformation.

Animals↗
PubMed1984

Effect of treatment regimens for Neisseria gonorrhoeae on simultaneous infection with Chlamydia trachomatis.

We evaluated the effect of treatment of gonorrhea on simultaneous Chlamydia trachomatis infection by randomly assigning 293 heterosexual men and 246 heterosexual women with gonorrhea to receive one of the following treatment regimens: (1) 4.8 million units of aqueous procaine penicillin plus 1 g of probenecid, (2) nine tablets of trimethoprim-sulfamethoxazole daily for three days, or (3) 500 mg of tetracycline four times a day for five days. Among the men, gonococcal infection was cured in 99 per cent given penicillin plus probenecid, 96 per cent given trimethoprim-sulfamethoxazole, and 98 per cent given tetracycline. Among the women, only 90 per cent given tetracycline were cured, in contrast to 97 per cent given penicillin plus probenecid and 99 per cent given trimethoprim-sulfamethoxazole. Chlamydial infection, present in 15 per cent of the men and 26 per cent of the women, was cured in 30 of 32 patients given trimethoprim-sulfamethoxazole and 27 of 29 given tetracycline, but in only 10 of 23 given penicillin plus probenecid. Among chlamydia-positive patients, postgonococcal urethritis in men and cervicitis in women occurred more often in patients given penicillin plus probenecid. Salpingitis developed in 6 of 20 women given penicillin plus probenecid, but in only 1 of 26 given trimethoprim-sulfamethoxazole and in none of 24 given tetracycline. We conclude that the use of penicillin plus probenecid alone for gonorrhea in heterosexual patients carries an unacceptably high risk of postgonococcal chlamydial morbidity. Trimethoprim-sulfamethoxazole and tetracycline were highly effective against both pathogens and were well tolerated in men, but both drugs caused frequent side effects in women. The failure of tetracycline to cure gonorrhea in 10 per cent of women argues against its use alone; treatment with penicillin followed by tetracycline has been recommended for further trial.

Adolescent↗
PubMed1984

Influence of environmental conditions on exocrine pancreatic response to intravenous injection of ethanol or 2-deoxyglucose in the dog.

When dogs have free access to the outside, an intravenous injection of ethanol depresses secretin-stimulated exocrine pancreatic secretion by a vagally mediated mechanism. This was shown in two separate series of six and seven dogs each. When dogs were kept in air-conditioned windowless kennels, the response to a meal was unchanged but the response to ethanol was reversed to stimulation. In four dogs, ethanol 1 g/kg was given during a secretin infusion. Three months after changing from open to closed kennels the inhibition (-86% for protein output) was still present, but after 6 months ethanol produced a stimulation (+62%) of pancreatic secretion. This increase was abolished, but not reversed, by keeping the animals outside during the day for four weeks, whereas after three months there was a partial restoration of the inhibitory effect (-39%). In contrast, changing from an open to a closed kennel changed the initial response to 2-deoxy-D-glucose (2-DG), 100 mg/kg, from stimulation to inhibition. These results suggest that environmental conditions affect the cranial regulation of pancreatic secretion.

Animals↗
PubMed1984

Somatosensory-evoked potentials in spinal cord injuries.

Short-latency somatosensory-evoked potentials after peroneal nerve stimulation were recorded in 25 patients with long-standing incomplete spinal cord injuries. The results were correlated with the patient's ability to walk. Nine patients had normal latencies, and four of these patients had no useful function in their lower limbs. Sixteen patients had prolonged latencies, and eight of these had useful ambulation. It is concluded that the scalp-recorded somatosensory-evoked potentials from peroneal nerve stimulation does not reliably predict function after spinal cord trauma.

Adult↗
PubMed1984

Metastatic prolactin-secreting pituitary adenoma.

A 62-year-old man had a malignant prolactin-secreting pituitary adenoma. The tumor was initially resected through a transfrontal approach. Recurrence six years later was manifested by an occipital metastasis, which was excised. Progressive clinical deterioration ensued despite irradiation and chemotherapy of the intrasellar and occipital recurrence, and the patient died. Pathologic examination of tumor tissue obtained from the occipital metastasis showed increased cellular pleomorphism and mitotic rate in comparison with the original surgical specimen. The only true indication of malignant transformation, however, was the invasion of tumor capsule by adenoma cells, observed in the autopsy specimen. These findings support the contention that the diagnosis of a malignant pituitary adenoma rests ultimately on the demonstration of local invasive growth and/or distant metastasis. Since prolactinomas are usually non-aggressive, malignant degeneration of adenomas is decidedly rare. Its occurrence underlines the need for aggressive follow-up and treatment.

Adenoma↗
PubMed1984

Age-related changes in laboratory values used in the diagnosis of anemia and iron deficiency.

Laboratory results from the Second National Health and Nutrition Examination Survey (NHANES II) were used to define age-related changes in laboratory values that are related to the diagnosis of anemia and iron deficiency. Analyses included Hb, hematocrit, red blood cell count, red cell indices, iron, total iron-binding capacity, transferrin saturation, and erythrocyte protoporphyrin. Computation of median values and 95% ranges by age and sex for each laboratory test were performed on 15,093 subjects between 1 and 74 yr of age who had complete laboratory data on venous blood, after excluding those subjects with an abnormality in one or more of three other laboratory tests. Age-related changes in laboratory measurements, such as those described herein, must be taken into consideration in order to optimize the identification of individuals with anemia and iron deficiency.

Adolescent↗
PubMed1984

Prevalence and causes of anemia in the United States, 1976 to 1980.

We estimated the prevalence of anemia in the United States from the results of the Second National Health and Nutrition Examination Survey ( NHANES II, 1976 to 1980). Reference ranges for Hb were first derived from 11,547 subjects in whom laboratory values for serum iron/iron-binding capacity, mean corpuscular volume, and erythrocyte protoporphyrin were all normal (greater than or equal to 16%, greater than or equal to 80 fl, and less than or equal to 75 micrograms/dl red blood cells, respectively). Using these reference standards, the prevalence of anemia (Hb values below the 95% reference range for age and sex) among the 15,093 subjects with complete laboratory results was highest in infants (5.7%), teenage girls (5.9%), young women (5.8%), and elderly men (4.4%). The pattern of laboratory abnormalities in anemic subjects indicated that iron deficiency predominated as a cause in infants and young women in contrast to inflammatory disease in the elderly.

Adolescent↗
PubMed1984

Comparison of rewarming by radio wave regional hyperthermia and warm humidified inhalation.

Anesthetized random source dogs were cooled by ice water immersion to a stable core temperature of 25 degrees C and subsequently rewarmed with warm humidified inhalation (43 degrees C, 450 cc of min ventilation X kg-1) or radio-frequency induction hyperthermia (4-6 watts X kg-1). The mean time required for core rewarming to 30 degrees C was 280 +/- 114 min for ventilation and 58 +/- 13 min for radio wave therapy (p less than 0.001). There was no evidence of tissue damage with either modality. These data suggest radio wave heating is superior to warm humidified inhalation therapy for core rewarming of rapidly induced immersion hypothermia.

Animals↗
PubMed1984

Hearing-impaired children's performance on the Edgerton and Danhauer Nonsense Syllable Test.

The monaural performance of 7 girls, aged 8:8-14:8 yrs, with mild-to-moderate hearing losses, was assessed at SLs of 25, 35, 45, and 55 db on List A of a commercially available taped version (Auditec of St. Louis) of the Edgerton and Danhauer (1979) nonsense syllable test (NST). Ss' verbal responses were transcribed phonetically and scored by phoneme, consonant, vowel, and bisyllabic methods. The phoneme method was preferred. There were no age effects. Performance improved slightly as SL increased. Results were favorably compared to those of earlier studies on this and other versions of the NST; these preliminary data indicate that the NST is useful for assessing children's phoneme perception.

Adolescent↗
PubMed1984

The syndrome of bulimia. Review and synthesis.

This comprehensive review of the syndrome of bulimia outlines treatment modalities including response prevention, cognitive behavioral and group interventions, and antidepressant pharmacotherapy. The authors propose an etiologic model that synthesizes available data indicating that young women who are at risk for developing bulimia appear to have a biologic vulnerability to affective instability, have family environments that are conflicted and disorganized, and a variety of personality traits that result in low self-esteem and self-regulatory difficulties.

Adolescent↗