The establishment of a macrophage-like cell line (Ymnu) from NMRI mice treated with N-methyl-N-nitrosourea. I. Characterization of the cell line

Here we describe the establishment of a cell line from peritoneal exudate cells for NMRI-mice treated with methylnitroso urea, which we designate Ymnu. Tests for macrophage specific characteristics have shown that 54% of Ymnu cells possess Fc-gamma receptors, 30% are nonspecific esterase positive and 65% possess the macrophage specific antigen Mac-1, indicating their macrophage origin. Although of macrophage origin, the majority of these cells are round, 13 microns in diameter. The cells grow partially in suspension and have doubling times varying from 3 to 1.75 days depending on serum concentration. Cultures of Ymnu cells achieve after 14 days densities 4 times higher than those achieved by NIH-3T3 cells. Ymnu cells have lost the anchorage dependence of growth and grew very well on semi-solid media. In addition, they possess an oncogenic potential and build tumors when injected subcutaneously in nude mice.

Effect of a nasogastric tube on esophageal pressure measurement in normal adults

We studied the correspondence between fluctuations of esophageal pressure measured before and after placement of a nasogastric (NG) tube in six normal volunteers. Flow, airway pressure, and esophageal pressure data from at least 20 breaths were recorded in seven ventilatory conditions in two body postures: 0 degree (supine) and 60 degrees (upright). The conditions studied included normal quiet breathing, added resistance, reduced compliance, increased frequency, increased tidal volume, continuous positive airway pressure, and volume-cycled ventilation with positive pressure. During recording with the NG tube in place, the subject targeted the same tidal volume (VT), respiratory rate, and inspiratory time fraction (TI/TTOT) recorded before NG tube placement. A computer program selected for analysis only those recorded breaths with and without an NG tube that were "matched" within 5 percent for both VT and TI. We calculated average VT, TI, and esophageal pressure fluctuation (delta Pes) for the matched breaths from each subject during every condition. The delta Pes values with and without NG tube were not statistically different in any tested condition (p > 0.05). Our data indicate that the presence of an NG tube does not invalidate the accuracy of delta Pes measurements made using a well-positioned balloon catheter in the tested conditions.

Emergency-department diagnosis of acute myocardial infarction and ischemia: a cost analysis of two diagnostic protocols

OBJECTIVE

To assess the potential cost savings of the emergency-department (ED) diagnosis of acute myocardial infarction (AMI) and other myocardial ischemia using a nine- hour ED evaluation protocol.

METHODS

This one-year study of chest-pain evaluation unit (CPEU) patient charges was undertaken at two midwestern urban university hospital EDs. Included in the study were 447 patients presenting to the EDs with chest pain consistent with myocardial ischemia, nondiagnostic electrocardiograms (ECGs), and stable vital signs. Following initial ED evaluation, CPEU patients underwent nine hours of continuous ECG ST-segment monitoring with serum CK-MB levels determined at zero, three, six, and nine hours. Nonrandomized concurrent chest pain patients with routine ED evaluation and hospital admission without CPEU workup served as controls. At Center 1, patients with negative CPEU evaluations underwent immediate echocardiography (echo) and graded exercise testing (GXT) followed by ED release (CPEU;REL). At Center 2, CPEU patients were released from the ED for outpatient stress thallium testing (CPEU;REL). At Center 2, CPEU patients with positive workups as indicated by elevated CK-MB levels, ischemia by ST-segment monitoring, or positive echo/GXT/ stress thallium testing were admitted to the hospital for further testing. Control patients were admitted directly to the hospital to evaluate for AMI. Hospital charges for CPEU and control groups were compared.

RESULTS

(Total charges in dollars, mean +/- SD, student's t-test): [table: see text]

CONCLUSION

At both centers, hospital charges related to the acute evaluation of chest pain were significantly lower with this ED diagnostic protocol for AMI and myocardial ischemia.

Studies in hypotensive agents. Synthesis and hypotensive activity of 3,4-dihydro-1(2H)-benzoxepine oxime ethers and their derivatives

Substituted oximino-ethers of 3,4-dihydro-1(2H)-benzoxepines were synthezised from 3,4-dihydro-1(2H)benzoxepin-5-ones. The hypotensive activity of these compounds was evaluated on anaesthetized cats.

High-dose chemotherapy-induced platelet defect: inhibition of platelet signal transduction pathways

Patients receiving high-dose chemotherapy and autologous bone marrow transplantation acquire a platelet secretion defect. The role of chemotherapeutic agents and their metabolites in mediating this platelet defect was investigated. 1,3-Bis(2-chloroethyl)-1-nitrosourea (BCNU), but not cyclophosphamide or cis-platinum, was found to inhibit platelet aggregation in vitro in response to activation by either ADP, thrombin, or collagen. Inhibition by BCNU was dose dependent and required preincubation of platelets with BCNU. After a 60-min preincubation, 30 microM BCNU produced 50% inhibition of platelets in platelet-rich plasma. The cyclophosphamide metabolites acrolein and 4-hydroperoxycyclophosphamide also inhibited platelet aggregation in a dose-dependent manner, with a requirement for preincubation. Platelet inhibition occurred at clinically relevant concentrations of BCNU and metabolites of cyclophosphamide. The effects of acrolein were totally prevented by coincubation with the sulfhydryl-protecting agents N-acetylcysteine and 2-mercaptoethanesulfonic acid, whereas the effects of BCNU were incompletely prevented. The mechanism of platelet inhibition was investigated next by examining protein phosphorylation in response to platelet agonists. Acrolein inhibited thrombin- and phorbol ester-induced phosphorylation of a 40-kDa polypeptide and other substrates, indicating a cellular defect in protein kinase C signaling. BCNU did not interfere with protein phosphorylation, indicating preservation of initial signaling pathways. Thus, chemotherapeutic agents and their metabolites inhibit platelet function by inhibiting distinct components of the intracellular activation pathways.

Antimicrobial screening of essential oils and extracts of some Humulus lupulus L. cultivars

The essential oils as well as solvent extracts of 11 hop cultivars, 1 hop variety and a wild type of hop were screened for their antimicrobial activities using the agar overlay technique. The oils were isolated from the cones of the various hop plants by hydrodistillation, the extracts were obtained by soaking the hop cones in chloroform. The oils and the extracts showed activity against the Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and the fungus (Trichophyton mentagrophytes var. interdigitale), but almost no activity against the Gram-negative bacterium (Escherichia coli) and the yeast (Candida albicans) used in the screening. The peak area percentages of the main volatile components and the contents of the bitter acids of the extracts were determined for all cultivars using chromatographic methods.

Epidemiology of infertility

Recent infertility literature has focused on the epidemiologic evaluation of diagnostic and therapeutic measures. The predictive value of the postcoital test and the sperm penetration assays has been called into question, particularly for female factor infertility. Several studies have sought better prognostic guidelines for assisted reproductive technologies such as artificial insemination by donor and in vitro fertilization and embryo transfer, as well as more cost-effective screening measures for evaluating infertile couples. Recent epidemiologic investigations have found no adverse effects of infertility therapy on the health of mothers or their babies.