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Biomedical subjects

J D Johnson

Publications and source records attributed to J D Johnson.

At least 307 records · Page 17Linked to original sources
PubMed1980

New transfusion program for an intensive care nursery.

We have established a new transfusion program for an intensive care nursery which is based on crossmatching several infants to the same unit of type O Rh0(D) negative packed red blood cells, dividing the unit into quadpacks, and allowing multiple entry into each quadpack over a 24-hour period in the nursery. With this procedure, each donor unit can be used to provide multiple transfusions to four infants over a four-day period. Follow-up of transfusion recipients revealed that 20% had evidence of previous or ongoing CMB infection at 10 months of age, a prevalence comparable to that for transfused infants in other studies. We found no evidence for transmission of HB infection and a low risk of allosensitization to red cell and lymphocyte antigens.

Blood Transfusion↗
PubMed1980

Posthemorrhagic hydrocephalus in low-birth-weight infants: treatment by serial lumbar punctures.

We have performed weekly computed tomographic brain scans on 28 surviving low-birth-weight infants with cerebral intraventricular hemorrhage and acute ventricular dilatation. Evolving hydrocephalus was observed in 15 infants. Twelve of the 15 infants were treated by removing large volumes of cerebrospinal fluid with serial lumbar punctures. Arrest in the progression of hydrocephalus was evident in 11 of the 12. Clinical hydrocephalus requiring surgical intervention occurred in one of the treated infants and in all three untreated infants. No complications of serial lumbar punctures were noted, whereas shunt-related morbidity was 100%. Our results suggest that serial lumbar punctures are effective in arresting the development of posthemorrhagic hydrocephalus.

Brain↗
PubMed1980

Prediction of bladder tumor invasion with the mixed cell agglutination test.

The mixed cell agglutination test was used to investigate 30 patients with initially superficial (stage 0 to A) transitional cell bladder tumors who had been followed a minimum of 5 years, until cystectomy or until death in an effort to select those patients who would suffer invasive disease. All tumor-bearing tissue was coded and studied without knowledge of the blood type or clinical status of the patient. Of the 15 patients with a negative mixed cell agglutination test 9 (60%) suffered invasive disease. None of the patients with a positive mixed cell agglutination test had invasive disease. The ultimate outcome then was predicted correctly in 24 of 30 patients (80%) (p less than 0.001). When the mixed cell agglutination test is positive it is associated with a good prognosis, while the majority of patients with a negative test are destined to suffer invasive disease.

Agglutination Tests↗
PubMed1980

Malignant fibrous histiocytoma of the spermatic cord.

We present 3 cases of malignant fibrous histiocytoma arising from the spermatic cord. This tumor occurs rarely in genitourinary organs and only 2 cases involving the spermatic cord have been reported previously. Recurrence rates of approximately 44 per cent of malignant fibrous histiocytoma in other sites are not improved by radiation or chemotherapy as adjuvants or primary means of treatment. Radical inguinal orchiectomy along with wide en bloc local resection is the therapy of choice.

Aged↗
PubMed1980

Transcription and processing of a yeast tRNA gene containing a modified intervening sequence.

The tRNA(3) (Leu) gene from yeast contains an intervening sequence of 32 nucleotides not present in mature tRNA. This sequence is transcribed and subsequently removed during the maturation of the RNA. To probe the involvement of this region of the gene in transcription and processing of the pre-tRNA(3) (Leu), the yeast DNA was cloned in plasmid pBR322 and a 21-base-pair DNA fragment corresponding to the lac operator was inserted into the intervening sequence. Insertion was done at a cleavage site for the restriction endonuclease Hpa I that occurs 19/20 base pairs from the 5' end of the intervening sequence. The parent and modified plasmids were then transcribed in a Xenopus germinal vesicle extract. RNA-fingerprint analysis of the transcription products revealed that both the tRNA(3) (Leu) gene and its modified counterpart were accurately transcribed. Transcription products corresponding to mature tRNA(3) (Leu) and pre-RNA(3) (Leu) with the normal and lac-containing intervening sequence were identified. Precursors extended at their 5' and 3' ends were also present. Both parent and modified genes were transcribed efficiently, and the various products accumulated in similar amounts, indicating that no deleterious effects on transcriptional competence, stability of the transcripts, or processing result from insertion of the 21-base-pair lac operator DNA. Incubation of pre-tRNA molecules that contained intervening sequences but were 5' and 3' mature with a yeast ribosomal wash fraction resulted in excision of the intervening sequence and, in the presence of ATP, ligation of the resulting half-tRNA molecules. The presence of RNA complementary to lac operator DNA neither inhibited the excision and splicing activities nor altered the site of the junction.

Base Sequence↗
PubMed1980

Ambulatory surgery in an HMO. A study of costs, quality of care and satisfaction.

This study is a retrospective examination of data from a prepaid group practice that introduced a change in surgical services so that about 35 per cent of patients having surgery in the operating room were not admitted to the hospital. The study population is the membership of the Oregon Region of the Kaiser Foundation Health Plan for the period 1966 through 1974. The data come from 100 per cent of the hospital admissions and 100 per cent of the ambulatory (nonadmit) surgical procedures. This study examines the costs, quality of care, and satisfaction of providers and patients with ambulatory surgery. Cost savings for the ambulatory procedures averaged +192.19 per procedure (based on 1977 costs). National savings for 1977 were projected at +773,947,208. In addition, ambulatory surgery absorbed an increasing demand for surgical procedures without requiring additional hospital beds. No difference in quality of care were found for inpatients and ambulatory patients (both used the same operating rooms and staff), and both providers and patients were found to be very satisfied with ambulatory surgery services.

Ambulatory Surgical Procedures↗
PubMed1980

Effect of ionic environment on the inactivation of poliovirus in water by chlorine.

The rate of inactivation of poliovirus in water by chlorine is strongly influenced by the pH, which in turn influences the relative amounts of HOCl and OCl- that are present and acting on the virus in the region of pH 6 to 10. The distribution of HOCl and OCl- is influenced to a lesser extent by the addition of NaCl. The major part of the sharp increase in disinfection rate seen with this salt is thought to be due to its effect on the virus itself resulting in an increased chlorine sensitivity, especially at high pH.

Chlorine↗
PubMed1980

Antibiotic uptake by alveolar macrophages.

Optimal therapy of infections caused by bacteria able to survive within phagocytes requires the use of antibiotics which inactivate these intracellular organisms. To define characteristics that determine entry of antimicrobial agents into phagocytes, we studied the uptake of 14 radiolabeled antibiotics by rabbit AM. Cell-antibiotic mixtures were incubated for 2 hr, and at intervals antibiotic uptake was determined by velocity-gradient centrifugation (separation of cells from extracellular antibiotic). Many drugs failed to penetrate AM readily. Cellular concentrations of penicillin G and three cephalosporin antibiotics were much lower than extracellular levels (C/E = less than 0.1 to 0.4). Gentamicin, isoniazid, and tetracycline attained C/E values of 0.5 to 0.8. The more lipid-soluble antibiotics, refampin, lincomycin, and chloramphenicol, were concentrated approximately twofold (C/E = 2) in AM. Ethambutol (C/E = 7) and two erythromycin preparations (C/E = greater than 20) were markedly accumulated by macrophages. In comparison with other antibiotics tested, the uptake of clindamycin was both massive and rapid (C/E = 50 by 30 min). Ethambutol, erythromycin and clindamycin uptakes by AM are dependent upon oxidative metabolic processes. Detailed characterization of clindamycin uptake confirmed that the drug is accumulated by an active transport system. These findings, in association with studies of antibiotic-mediated influence on phagocytes, should provide information useful in establishing guidelines for optimal antibiotic usage.

Animals↗
PubMed1980

Pulmonary excretion of carbon monoxide in the human infant as an index of bilirubin production. IV. Effects of breast-feeding and caloric intake in the first postnatal week.

Measurements of the pulmonary excretion rate of carbon monoxide (VEco) as an index of bilirubin production in the first several days of life were taken from 64 breast-fed or bottle-fed infants. Twenty-one infants (greater than or equal to 37 weeks of gestation) were breast-fed; 43 infants (28 to 42 weeks of gestation) were bottle-fed a commercially prepared formula. Information pertaining to their caloric intake during the 24-hour period preceding VEco determination was taken from 38 of the 43 infants who were bottle-fed and they were placed into three groups based on their caloric intake: (1) less than or equal to 60 kcal/kg/day (19 infants); (2) 61 to 100 kcal/kg/day (7 infants); and (3) greater than 100 kcal/kg/day (12 infants). There was no significant difference in bilirubin production between bottle-fed and breast-fed infants. No effect of caloric deprivation on bilirubin production was demonstrated. The mean VEco values were 18.5 +/- 0.9 (SE) for group 1, 17.7 +/- 1.8 (SE) for group 2, and 16.2 +/- 1.1 (SE) microliter/kg/hr for group 3.

Bilirubin↗
PubMed1980

Use of the conjugated polyene fatty acid, parinaric acid, in assaying fatty acids in serum or plasma.

We describe a method for rapidly assaying fatty acid concentrations in plasma or serum. This method is particularly appropriate for monitoring increased concentrations of fatty acids that may be present during intravenous lipid infusion, especially in neonates. Binding cisparinaric acid (9, 11, 13, 15-cis-trans-trans-cis-octadecatetraenoic acid) to albumin shifts the absorption spectrum of the acid. If fatty acids are present in serum, they will compete with parinaric acid for binding, changing the extent of this absorption shift. The measurement requires a spectrophotometer, 30 microL of serum or plasma, and knowledge of the sample's albumin concentration.

Bilirubin↗
PubMed1979

Interaction of alpha-chymotrypsin with the fluorescent probe 1-anilinonaphthalene-8-sulfonate in solution.

The binding of the fluorescence probe 1-anilinonaphthalene-8-sulfonate (Ans) to alpha-chymotrypsin (alpha-CHT) at pH 3.6 is accompanied by a dramatic enhancement of Ans fluorescence and a shift of the emission maximum to shorter wavelengths. Our study reveals that one Ans molecule binds to alpha-CHT at a site different from either the active site of alpha-CHT or the 2-p-toluidinylnapthalene-6-sulfonate binding site. the binding constant of Ans is about the same (10(4) M-1) at pH 3.6 and 6.4. Nanosecond fluorescence depolarization data indicate that Ans is rigidly bound to alpha-CHT. The fluorescence enhancement due to binding of Ans to alpha-CHT at low pH could be due to binding either to a hydrophobic site or to a site where local dipoles do not relax during the excited-state lifetime of Ans. As the pH is increased, fluorescence intensity of the Ans-alpha-CHT complex decreases appreciably; and the emission maximum shifts to longer wavelengths. The fluorescence decay curves exhibit a corresponding sensitivity to pH. The pH effect on the fluorescence of Ans-alpha-CHT can be interpreted in terms of a pH-dependent equilibrium between alpha-CHT conformers differing in the degree of mobility of polar residues and water molecules at the Ans binding site or structural changes in the Ans binding site.

Allosteric Site↗