Systemic absorption of endotracheally administered aminoglycosides in seriously ill patients with pneumonia.

A study was performed with 10 hospitalized patients to determine the percentage of an aminoglycoside dose (tobramycin or gentamicin) that is absorbed systemically after being instilled into the endotracheal tube at steady state. All patients were on respirators, had indwelling urinary catheters, and had creatinine clearances estimated to be greater than or equal to 40 ml/min. Tobramycin or gentamicin (40 mg) was instilled every 4 h directly into the endotracheal tube. Nine patients also received systemically a different aminoglycoside from that administered through the endotracheal tube. Urine was collected over a 4-h dosing interval at steady state (after at least 5 doses of the drug). The amount of aminoglycoside excreted over the 4-h interval was measured and expressed as percentage of the dose administered over that period. The range of percentage of dose absorbed was 1.5 to 34%, with a mean of 16.7 +/- 11.4% standard deviation and a median of 16.5%. The coefficient of variation was 68%. Levels of the endotracheally administered aminoglycoside in serum were measured, and all were less than 1.0 microgram/ml. While a large degree of variability in absorption was observed in this study, significant amounts of aminoglycosides could be absorbed in some patients. However, levels apparently did not accumulate in sera of patients with adequate renal function, and an empirical dosage reduction in intravenous aminoglycoside should not be necessary with the addition of endotracheally instilled aminoglycoside in patients with creatinine clearances greater than 40 ml/min.     

A simple bioassay for epidermal growth factor using pig thyrocytes.

A bioassay for epidermal growth factor (EGF) is described using an eluted stain assay (ESTA) of dehydrogenase activity in pig thyrocytes. Optimal responsiveness to EGF was obtained in confluent cultures of primary pig thyrocytes cultured with EGF or biological samples containing EGF for either 24 or 48 h. Dehydrogenase activity was determined by measuring the production and then the release of a coloured formazan product produced by reduction of a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide substrate added to the cells. The assay responded equally to mouse, human and recombinant EGF and was suitable for measuring EGF activity in some but not all biological fluids. Specificity of detection of EGF activity was confirmed using antibody to EGF. The ESTA assay compared favourably with the radioreceptor assay for EGF in terms of sensitivity to EGF with half-maximal activation at 0.24 +/- 0.06 nmol/l (mean +/- S.E.M., n = 22 experiments) for the ESTA assay and 0.60 +/- 0.13 nmol/l (n = 7 experiments) for the radioreceptor assay.     

Bromocriptine inhibits pro-opiomelanocortin mRNA and ACTH precursor secretion in small cell lung cancer cell lines.

We have previously reported that a human small cell lung cancer (SCLC) cell line (COR L103) that expresses the proopiomelanocortin (POMC) gene and secretes ACTH precursor peptides is relatively resistant to glucocorticoid regulation. Using this model, we have now examined alternative regulatory mechanisms of the POMC gene and found that both the mRNA and ACTH precursor peptides were stimulated four- and two-fold, respectively, after 48 h incubation with db-cAMP. Next, we examined the dopamine agonist, bromocriptine, which acts predominantly through D2 receptors linked to adenyl cyclase to cause a reduction in intracellular cAMP. Bromocriptine suppressed cAMP levels and inhibited precursor peptide secretion within 24 h in a dose-dependent manner (0.15-15 microM). At the highest dose, peptide secretion was inhibited from 95 to 53 pmol/mg protein, and POMC mRNA was reduced by 50%, while beta-actin mRNA remained unchanged. This effect could not be mimicked by incubation of cells with the alpha-adrenergic antagonist, phenoxybenzamine, suggesting that the alpha-adrenergic effects of bromocriptine were not responsible for this observation. These cells also secrete estradiol, but the secretory rate was unaffected by bromocriptine, suggesting, with the beta-actin data, that the POMC inhibition was not a cytotoxic effect. No recovery in precursor peptide secretion was seen in a 48-h period after the removal of bromocriptine. However, when the postchallenge incubation was extended to 8 d, there was a recovery in secretory potential between day 3 and day 8 and normal growth kinetics in the 4 d after removal of the drug. In contrast to these findings, the mouse corticotroph cell line, AtT20, showed no response to bromocriptine, in keeping with reports that this agonist has no effect on anterior lobe corticotrophs. We conclude that bromocriptine effectively inhibits POMC expression in SCLC cells, and that this phenomenon might be of useful clinical application.     

Correlation between class I antigen expression and the ability to generate tumour infiltrating lymphocytes from bladder tumour biopsies.

Analysis of tissue sections from transurethrally resected bladder tumours using anti-CD3 antibody showed the presence of T lymphocytes in intra-epithelial layers in eight of 12 cases investigated. In a larger group of patients, Tumour Infiltrating Lymphocyte (TIL) growth was established from six of 19 cases using Interleukin-2 (IL-2) and conditioned medium (CM) and resulted in the expansion of TILs up to 100-fold. TILs from these individuals were phenotyped with W6/32 (anti-HLA-A,B,C), HB55 (anti-DR) and anti-CD3 antibodies using FAC sorter. The mean +/- s.d. frequency of positive staining with these antibodies were 96.7 +/- 4.0%, 87.5 +/- 10.0% and 82.5 +/- 7.8% respectively, indicating the activated nature of these T cells. The cytotoxic activity of these TILs against Daudi (ie, LAK activity) cell line at 25/1 E/T ratios varied from 26.3 +/- 3.2 to 62.8 +/- 5.2%. In one case where TILs and autologous tumour cell line were established, cytotoxicity studies showed low level of cytotoxicity against the autologous tumour cells (15.8 +/- 1.6%) compared with 62.8 +/- 5.2% against Daudi. Staining of tumour sections from these 19 individuals with W6/32 and BBM.1 revealed positive staining in six of six that developed TILs but only six of 13 (46%) cases, whose tumour failed to grow TILs (P less than 0.02, Fisher exact test). These results are indicative of the presence of IL-2 passageable T cells in bladder cancer biopsy and demonstrate that the successful expansion of these cells correlates with the normal expression of class I antigens on the tumour cells.     

Detection of human papillomavirus-genomic DNA in oral epithelial dysplasias, oral smokeless tobacco-associated leukoplakias, and epithelial malignancies

Human papillomavirus (HPV) is an infectious agent that is increasingly associated with mucosal cancers, in particular cancer of the cervix. The present investigation was undertaken in an attempt to determine whether HPV could be easily detected in biopsies of oral tissues, specifically oral squamous cell carcinomas, oral epithelial dysplasias, smokeless tobacco keratoses, verrucous hyperplasia, and verrucous carcinoma. In situ DNA hybridization methods were used to isolate specific HPV genomes. Among 100 instances of benign leukoplakia, only 4% of non-tobacco-related and 10% of smokeless tobacco-related lesions harbored viral sequences. We were able to detect viral sequences in dysplastic lesions 3% of the time. Alternatively, 17% and 20% of the verrucous hyperplasias and verrucous carcinomas were positive for viral nucleic acids. Six percent of the squamous cell carcinomas harbored HPV. On the basis of these findings, it is concluded that HPV of known genotype can be identified in oral premalignant and malignant neoplasms.     

Long-term care nurses identify educational needs regarding quality assessment and improvement.

An increasing demand is being placed on nurses who are practicing in long-term care settings to conduct and/or participate in quality assessment and improvement (QAI) activities. A local survey of directors of nursing in long-term care indicated both personal interest and interest on the part of their staff nurses to attend continuing education (CE) programs regarding quality of care to increase their competencies in this area. Specific interest areas and recommendations for an educational offering regarding quality assessment and improvement for long-term care nurses are described.     

Induction of Sustained Hemopoiesis in Fatty Marrow

Evacuation of the fatty marrow cavity resultsin a sequence of regeneration which is associated with a phase of hemopoiesis. Hemopoieticactivity is, however, transient, being replacedby adipose tissue, so that 6 mo after evacuationthe marrow is once again fatty. This phase oftransient hemopoiesis can be sustained byphenylhydrazine-induced hemolytic stress. Hemolysis per se does not induce significanthemopoietic activity in nonevacuated totallyfatty marrow.

Submitted on May 17, 1973 Revised on July 9, 1973 Accepted on July 16, 1973