Effect of tracheal gas insufflation on gas exchange in canine oleic acid-induced lung injury

OBJECTIVE

To determine the effect of tracheal gas insufflation on gas exchange in oleic acid-induced lung injury in dogs.

DESIGN

Prospective, longitudinal study.

SETTING

University research laboratory.

SUBJECTS

Five mongrel dogs.

INTERVENTIONS

The dogs were anesthetized, paralyzed, and mechanically ventilated. Lung injury was induced by infusing 0.09 mL/kg of oleic acid and pulmonary artery occlusion (wedge) pressure (PAOP) was increased to 15 mm Hg by infusing fluids to enhance pulmonary edema formation. After 60 mins, PAOP was allowed to decrease to 5 mm Hg and was maintained at 5 mm Hg for 60 mins to stabilize the pulmonary edema. We studied the effect of tracheal gas insufflation on gas exchange at low and high end-expiratory lung volumes achieved by a positive end-expiratory pressure of 5 and 12 cm H2O, respectively. The FIO2 values of the ventilator and catheter were equivalent (0.6). Each tracheal gas insufflation stage at low and high end-expiratory lung volume was preceded and followed by conventional mechanical ventilation stages without tracheal gas insufflation. During transitions between conventional mechanical ventilation and tracheal gas insufflation, end-expiratory lung volume was maintained constant by adjusting positive end-expiratory pressure while monitoring esophageal pressure and inductive plethysmography. Tidal volume was maintained constant throughout the protocol (0.40 L). MEASUREMENTS AND MAIN RESULTS. At end stage, we measured PaCO2, PaO2, total physiologic deadspace fraction, and venous admixture, which were 43 +/- 4 torr (5.7 +/- 0.5 kPa), 325 +/- 6 torr (43.3 +/- 0.8 kPa), 53 +/- 3%, and 4.0 +/- 0.3% before oleic acid lung injury, respectively. After oleic acid injury at low end-expiratory lung volume, these variables were 55 +/- 4 torr (7.3 +/- 0.5 kPa), 73 +/- 13 torr (9.7 +/- 1.7 kPa), 61 +/- 4%, and 50 +/- 7%, respectively. During tracheal gas insufflation at low end-expiratory lung volume conditions, PaCO2 and the total physiologic deadspace fraction decreased significantly (p < .05) to 45 +/- 4 torr (6.0 +/- 0.5 kPa) and 50 +/- 5%, respectively. Under high end-expiratory lung volume conditions, PaCO2 and the total physiologic deadspace fraction were 55 +/- 7 torr (7.3 +/- 0.9 kPa) and 61 +/- 6%, respectively; during tracheal gas insufflation, these variables decreased to 43 +/- 4 torr (5.7 +/- 0.5 kPa) and 52 +/- 5%, respectively (p < .05). Increasing end-expiratory lung volume improved both PaO2 and venous admixture (p < .05) but tracheal gas insufflation had no significant effect on oxygenation efficiency when end-expiratory lung volume was held constant.

CONCLUSIONS

Tracheal gas insufflation augmented alveolar ventilation effectively in the setting of oleic acid-induced lung injury in dogs. When end-expiratory lung volume and tidal volume were kept constant, tracheal gas insufflation did not affect oxygenation.

The establishment of a macrophage-like cell line (Ymnu) from NMRI mice treated with N-methyl-N-nitrosourea. II. Induction of differentiation of Ymnu cells: a cytochemical and immunocytochemical study

The Ymnu cell line established by us from peritoneal exudate cells of mice treated with methylnitrosourea is of macrophage origin. We have shown that 54% of these cells possess Fc-gamma receptors and can bind opsonized erythrocytes; 30% of these cells express the nonspecific esterase and 65% the Mac-1 antigen, indicating these cells are dedifferentiated. Treatment of the cells with various differentiation inducers led to time-dependent redifferentiation of the cells. The expression of the nonspecific esterase increased to 51.1% (TPA), 42.5% (RA), 63.6% (DMSO), 40.6% (SB). The fraction of Mac-1 positive cells increased to 90.5% (TPA), 80.6% (RA), 84.5% (SB) and decreased to 52.7% (DMSO). The maximal effects of the chemicals on expression of these two parameters were achieved at different times following treatment. While RA and SB were effective after one day, the maximum effect of TPA was seen at day 5.

Gene-targeted inhibition of transactivation of human immunodeficiency virus type-1 (HIV-1)-LTR by antisense oligonucleotides

We have used an in vitro approach to study the efficiency of antisense oligonucleotides in inhibiting LTR-(HIV-1)-directed CAT expression catalyzed by tat protein, the functional protein of the transactivator gene. We selected the target sequence localized near the 5' end of the tat mRNA. The following conclusions can be drawn from the data presented here: a) Antisense oligonucleotides modified by conjugation of cholesterol at the 3' end have a severalfold higher inhibitory response, b) inhibitory response is dependent on the mode of introducing oligonucleotides, and c) the inhibition by antisense oligonucleotides is sequence specific and directed towards the targeted region. This approach could be useful for targeting functional regions of regulatory gene products and designing gene-targeted inhibitors of virus replication.

Hyperpnea limits the volume recruited by positive end-expiratory pressure

The effectiveness of positive end-expiratory pressure (PEEP) relates directly to alveolar recruitment. We tested the hypothesis that active use of expiratory muscles during labored breathing impairs the ability of PEEP to increase end-expiratory lung volume. Eight healthy volunteers naive to the purposes of our study were exposed to targeted end-expiratory pressures of 0, 5, and 10 cm H2O during mechanical ventilation applied by mouthpiece and noseclips at three levels of ventilation: resting and two levels (moderate and high) of CO2 stimulation (10.9 +/- 0.4, 19.9 +/- 0.5 and 27.5 +/- 0.5 L/min, respectively). Inductive plethysmography demonstrated that end-expiratory lung volume rose by an average of 98 +/- 5 ml/cm H2O PEEP during quiet breathing but by much less during the two levels (moderate and high) of CO2 stimulation: 78 +/- 6 ml/cm H2O and 47 +/- 5 ml/cm H2O (p < 0.05). Hyperpnea also shifted the distribution of the recruited volume toward regions sampled by the rib cage band of the plethysmograph. Whatever advantage expiratory muscle activity may have for minimizing the workload of the inspiratory muscles, the cost may be reduced effectiveness of PEEP in increasing lung volume and improving oxygen exchange.

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.

Novel features of retroviruses associated with human diseases

The last decade has witnessed a new chapter in the history of retrovirology. As of now, four human retroviruses have been identified and molecularly characterized. They are associated with a wide spectrum of human diseases including cancer, immunodeficiency and neurological disorders. By virtue of their clinical relevance, their novel genes and regulatory mechanisms these viruses have become the focal point of research in retrovirology. The study of these viruses is of fundamental importance in understanding the mechanisms leading to transformation of human cells and distortion of the immunological state.

A host-mediated in vivo/in vitro assay with peritoneal murine macrophages for the detection of carcinogenic chemicals

We have developed a host-mediated assay system for the detection of the transforming action of chemical carcinogens on peritoneal macrophages. Directly as well as indirectly acting carcinogenic substances administered intraperitoneally to NMRI mice could be examined in this way. Resident macrophages were recovered by peritoneal lavage from treated and untreated mice and were cultured in soft agar. After 5-6 days normal and transformed cells could be distinguished. Statistical analysis comparing cells, for example, from alpha-naphthylamine or diphenylhydantoin-treated animals with those from control mice proved that the test is positive at least on a significance level of 5% using the t-test. Further substances revealing a cell-transformation potential were benzene, benz(a)pyrene, 2,3,7,8-tetrachlorodibenzodioxin, N-nitrosodimethylamine, ethidium bromide, aflatoxin B1,N-methyl-N-nitrosourea, 1-methyl-3-nitro-1-nitrosoguanidine, 2-naphthylamine, dieldrin, suramin and trichloroethylene. A weak transforming potential was found for chlorambucil as well as for tetrachloroethylene. With toluene or azidothymidine no cell transformation could be observed. Several immortal cell lines could be established form NMRI mice treated with alpha-naphthylamine or N-methyl-N-nitrosourea. Athymic nu/nu mice injected subcutaneously with these cells developed tumors, establishing the oncogenic potential of these cell lines.

Retroviral expression in mononuclear blood cells isolated from a patient with osteopetrosis (Albers-Schönberg disease)

We report the presence of reverse transcriptase activity in the supernatant of long-term culture of mononuclear blood cells (monocytes and lymphocytes) isolated from a 27-year-old patient suffering from benign osteopetrosis. The enzyme was purified to homogeneity according to the technique of Chandra and Steel, by chromatography, first on DEAE-cellulose (DE 52) and then on phosphocellulose (P11). After purification, the enzyme was characterized biochemically for its template specificity and ionic requirements. The purified enzyme was able to transcribe poly(rA).(dT)12-18 and poly(rC).(dG)12-18 very efficiently and had a marked preference for Mg2+ ions over Mn2+ ions. The pattern of ionic dependency for this enzyme is similar to that of reverse transcriptases purified from human lymphotropic viruses. The patient was tested and found sero-negative for HIV-1, HIV-2, and HTLV-I and seropositive (immunoglobulin G) for cytomegalovirus. Epstein-Barr virus nuclear antigens (EBNA) were detected in the patient's B lymphocytes. Since reverse transcriptase is the hallmark of retroviruses, we suggest that a retrovirus may be involved in the etiology of osteopetrosis.

Substance misuse and HIV/AIDS risks among delinquents: a prevention challenge

In the United States, there is growing concern that adolescents are at increasing risk for HIV-1 infection due to recreational substance use and sexual activity. Self-report questionnaires from a sample of 224 incarcerated delinquents quantified associations between drug use, sex, and other behaviors which risk HIV-1 infection. High rates of substance use and HIV-risking behaviors were found. Significant correlations between levels of substance use and both behavioral and attitudinal barriers to HIV/AIDS prevention programming were observed. This evidence and other subgroup differences in denial of vulnerability and in practice of preventive behaviors indicate the need for different approaches to prevention. An integrated HIV/AIDS and substance misuse prevention program is discussed as a viable alternative to the usual knowledge-enhancing programs.

Profile Rolling of Gears: A Boundary Element Analysis

Profile rolling processes such as those for gears play a very important role in everyday manufacturing. It is demonstrated here that the boundary element method (BEM) can be used to analyze, efficiently and accurately, this class of problems involving both material and geometric nonlinearities, as well as contact boundary conditions. The BEM formulation is capable of using any of a class of combined creep-plasticity-constitutive models with state variables for the description of material behavior. The specific problem considered is plane strain profile rolling of straight-toothed spur gears using the constitutive model originally proposed by Hart. The numerical results obtained from the BEM analysis provide a lot of insights into the process of profile rolling and can become a useful tool in designing these forming processes.

D-penicillamine inhibits transactivation of human immunodeficiency virus type-1 (HIV-1) LTR by transactivator protein

D-Penicillamine, an amino acid analogue of cysteine, has been shown to inhibit the transactivation of HIV-1 LTR by the transactivator protein, tat protein. The transactivation was studied in Jurkat cells co-transfected with plasmids containing HIV-LTR sequences fused to the bacterial chloramphenicol acetyltransferase (CAT) gene and HIV tat gene. The expression of CAT activity was a measure of transactivation of LTR by the tat protein. Incubation of transfected Jurkat cells with D-penicillamine led to inhibition of CAT activity. This inhibition was found to be concentration-dependent; more than 90% inhibition of chloramphenicol acetylation was seen in extracts prepared from cultures incubated with 40 micrograms/ml of D-penicillamine. Earlier experiments have shown that D-penicillamine at 40 micrograms/ml can completely inhibit HIV-1 (HTLV-III B) replication in H9 cells [(1986) Drug Res. 36, 184-186]. These results suggest that inhibition of transactivation may be the molecular mechanism involved in the inhibition of HIV-1 replication by D-penicillamine.

Biochemical heterogeneity of reverse transcriptase purified from the AIDS virus, HTLV-III

The reverse transcriptase from AIDS virus, HTLV-III, was purified and characterized. The purified enzyme has a very high affinity for template primers (rC)n X (dG)12 and (rCm)n X (dG)12 compared to that for (rA)n X (dT)12. In addition, the HTLV-III reverse transcriptase was able to transcribe (rAm)n X (dT)12 very efficiently. The ionic requirements are unique in the sense that HTLV-III reverse transcriptase prefers Mg2+ as divalent ions to transcribe (rC)n X (dG)12 and (rA)n X (dT)12. The Mr of the enzyme is 95 000-98 000. Unlike the HTLV-I reverse transcriptase, the HTLV-III enzyme is highly stable and has a much higher activity in the presence of (rC)n X (dG)12; the Vmax for HTLV-III reverse transcriptase is several-fold higher than that for HTLV-I enzyme. The enzyme activity of the purified reverse transcriptase from HTLV-III was resolved into two peaks on a preparative isoelectric column, one at pH 5.75 and the other at pH 6.25. This leads us to conclude that the reverse transcriptase of HTLV-III is biochemically heterogeneous.

A Generalized Finite Element Analysis of Sheet Metal Forming With an Elastic-Viscoplastic Material Model

A finite element analysis for elastic-viscoplastic problems in the presence of large strains is presented in this paper. The formulation is capable of using any of a class of combined creep-plasticity constitutive models with state variables for the description of material behavior. The specific problem considered is plane strain sheet metal forming using the constitutive model originally proposed by Hart. Numerical results are presented for sample problems and the effects of variations in several process parameters, such as velocity, friction at punch, and die interfaces, are investigated. The present report includes membrane, bending, and shear effects as well as the coupling among them and no a priori assumption is made about the strain distribution across the thickness. Thus, it unifies the earlier approaches used in sheet metal forming analysis and helps in gaining crucial insights into the process of sheet metal forming. It can also be extended to other large strain design and manufacturing problems.

Serum cholesterol binding reserve percentage in diabetes mellitus

Serum cholesterol binding reserve percentage (SCBR%) in patients with diabetes mellitus (22.17 +/- 13.40%) was significantly lower than in controls (40.93 +/- 8.69%) (p less than 0.001). SCBR% of controls did not vary with age (age range 20-80 years). SCBR% declined significantly with increasing duration of diabetes. It also decreased with macrovascular complications and was lowest in multiple/fatal complications further corroborating the value of SCBR% as a risk indicator of atherogenesis. The relationship of SCBR% with treatment was very striking. All adequately controlled patients had a significantly higher SCBR% than those who were poorly controlled regardless of treatment modality and those adequately controlled on insulin had the highest SCBR%, which was close to that of normal controls.

Inhibitors of phenylethanolamine-N-methyltransferase: effects on brain catecholamine content and blood pressure in DOCA-salt hypertensive rats

Inhibitors [2-cyclooctyl-2-hydroxyethylamine (CONH), 1 aminomethylcycloundecanol (CUNH), 7,8-dichloro-1,2,3,4-tetrahydroisoquinoline (SKF64139), 2,3-dichloro-alpha-methylbenzylamine (DCMB), 8,9-dichloro-2,3,4,5-tetrahydro-1H-2-benzazepine(LY134046)] of phenylethanolamine N-methyltransferase (PNMT) were found to reduce blood pressure in deoxycorticosterone-salt (DOCA-salt) hypertensive rats. CONH, CUNH and DCMB, but not SKF64139 and LY134046, also lowered blood pressure in normotensive control rats. All of the PNMT inhibitors tested lowered hypothalamic epinephrine (Epi) content in both DOCA-salt hypertensive and normotensive rats. DCMB, SKF64139 and LY134046 also lowered brainstem Epi in both animal groups. From these data a good correlation could not be made between the blood pressure lowering effects of PNMT inhibitors and their effects on hypothalamic Epi content as had been observed in other animal models of hypertension (e.g. spontaneously hypertensive rats).

A norepinephrine-cyclic AMP link in the hypothalamic pathways which mediate fever induced by endotoxin and prostaglandin E2 in the rat

The changes in rectal temperature, metabolic rate, cutaneous temperatures and respiratory evaporative heat loss produced by an injection of a bacterial endotoxin piromen (4-40 ng in 1 microliter) into the anterior hypothalamus were assessed in conscious rats in both sexes from a wide range of body mass and at various ambient temperatures (TaS). Intrahypothalamic injection of piromen increased metabolism and decreased cutaneous temperatures which led to fever in rats at Ta 8-30 degrees C. The monophasic fever was not significantly correlated with either body mass, sex difference of the Ta at which the experiments are carried out. Furthermore, daily intrahypothalamic injections of piromen produced no pyrogenic tolerance. Intrahypothalamic injections of either prostaglandin E2, norepinephrine, aminophylline or dibutyryl cyclic AMP also produced increased metabolism and decreased cutaneous temperature which led to fever at Ta 8-30 degrees C. In addition, the fever induced by intrahypothalamic injections of piromen, prostaglandin E2 or nor-epinephrine was greatly antagonized by pretreatment with intrahypothalamic injections of alpha or beta adrenergic antagonist. However, the fever induced by dibutyryl cyclic AMP or aminophylline was not affected by pretreatment with adrenergic receptor blockade. The data indicate that a norepinephrine- cyclic AMP link occurs in the hypothalamic pathways which mediate the piromen-induced or the prostaglandin E2-induced fever in rats.