Acetyl glyceryl ether phosphorylcholine-stimulated human platelets cause pulmonary hypertension and edema in isolated rabbit lungs. Role of thromboxane A2

Macrophages, neutrophils, and platelets may play a role in acute edematous lung injury, such as that seen in the adult respiratory distress syndrome (ARDS), but their potential actions and interactions are unclear. Because stimulated human macrophages and neutrophils can release acetyl glyceryl ether phosphorylcholine (AGEPC), a potent platelet activator, we hypothesized that in ARDS, leukocyte release of AGEPC might stimulate platelets to release thromboxane A2 (TXA2), which then produces pulmonary hypertension and lung edema. In support of this premise, we found that pulmonary hypertension and edema occurred in isolated rabbit lungs perfused with human platelets and AGEPC, but not with platelets or AGEPC alone. Infusion of a vasodilator (nitroglycerin) to maintain base-line pulmonary artery pressures in lungs perfused with platelets and AGEPC prevented the development of lung edema suggesting that platelet and AGEPC-induced edema was hydrostatic in nature. Additional experiments suggested that the increased pressure was a result of TXA2 release from platelets stimulated by AGEPC. Specifically, preincubation of platelets with imidazole, a thromboxane synthetase blocker, prior to infusion with AGEPC significantly diminished pulmonary hypertension and prevented lung edema. Furthermore, pretreating lung preparations with 13-azaprostanoic acid, a TXA2 antagonist, before infusion of AGEPC and untreated platelets also reduced the pulmonary hypertension and blocked the lung edema. The role of TXA2 was further suggested when perfusates from lungs infused with platelets and AGEPC developed high levels of TXA2, whereas perfusates from controls did not. These results suggest that platelet aggregation induced by AGEPC may contribute to ARDS by releasing TXA2, which raises microvascular pressure and increases edema formation, especially when an underlying permeability defect is present.

The role of T, B and adherent cells in the in vitro immune response of TEPC-183-bearing mice

In order to analyse the mechanism of immunosuppression of plasmacytoma-bearing mice, the role of enriched T cells, B cells, and adherent cells from the spleens of normal and TEPC-183 plasmacytoma (IgM,k) bearing mice in the primary in vitro immune response was investigated. Nylon-wool-enriched fractions of T and B cells were used in the study of T-cell-dependent immune responses to the 2-4-6-trinitrophenyl ligand. When 5 × 10^-5M 2-mercaptoethanol (2-ME) was present in cultures, TEPC-183 spleen cells or their T- or B-cell-enriched fractions did not suppress the immune responses of normal spleen cells. However, in the absence of 2-ME, T- or B-cell fractions were as effective as unfractionated TEPC-183 spleen cells in causing suppression of normal immune responses.

T and B cells derived from TEPC-183 spleens gave minimal anti-trinitrophenyl specific plaque-forming-cell responses when co-cultured with adherent cells from either normal or TEPC-183 spleens. In contrast, either T- or B-cell fractions from TEPC-183 spleens were at least partially competent when co-cultured with B or T cells from normal spleens. The data thus suggest that the suppressed state of TEPC-183 spleen cells may be due to defective T—B cell interaction. It was consistently observed that splenic adherent cells from TEPC-183-bearing mice were neither suppressed nor suppressive for the in vitro immune responses of normal splenic lymphocytes at the ratios tested. Adherent peritoneal exudate (PE) cells from either normal or TEPC-183-bearing mice were equally suppressive for the in vitro immune responses of normal splenic lymphocytes at the PE cell to lymphocyte ratios of 1:10 and 1:35. Thus, the suppressive characteristic of adherent PE cells in this system is not specific for TEPC-183 plasmacytoma in mice.

TEPC-183 spleens were found to contain 35% or more esterase-positive cells, compared with approximately 5% esterase-positive cells present in normal spleens. The possible role of esterase-positive cells, T cells, B cells, and adherent cells in the observed suppression will be discussed.

Computation of ammonium bisulfate aerosol deposition in conducting airways

Experimental measurements of the growth of monodisperse dry NH4HSO4 aerosols by H2O vapor condensation have been reported in the literature. These data are incorporated into an aerosol deposition model to study the behavior of inhaled NH4HSO4 particles, which is of concern in relation to human health. The tracheobronchial tree is described by Weibel's model A morphology, and Landahl's formulas are used to compute particle deposition efficiencies. Enhanced losses in the trachea due to the action of the laryngeal jet are accounted for by using an empirical deposition efficiency equation. The effect of NH4HSO4 aerosol growth is quantitated by comparisons of total and intrabronchial deposition probabilities with those of a nonhygroscopic aerosol of equal aerodynamic size. Computations indicate that hygroscopic growth effects are a function of the size of the particles inhaled. Total deposition efficiencies of NH4HSO4-H2O droplet aerosols are greater than those of nonhygroscopic aerosols only if the former originate from dry NH4HSO4 particles exceeding a critical geometric diamter of 0.3 micrometer. Growth effects are explained in terms of the relative efficiencies of the dominant deposition mechanisms active in the lung.

Modelling determinants of health

The linear regression procedure of stepwise elimination has been used to examine the association between a range of environmental variables and infant mortality rates (IMR) in Sri Lanka. The nature of the water supply was found to be significantly associated with IMR. Latrines were significantly associated with IMR once qualitative differences between districts were allowed for. Other 'environmental determinants of health', 3 indices of housing quality and the presence of electricity supplies, were not significant. The cost of effecting changes in IMR by extending subsidies to water supply improvements is estimated.

Modeling the dose distribution of H2SO4 aerosols in the human tracheobronchial tree

The influence of hygroscopic growth within the human respiratory tract upon the deposition of H2SO4 aerosols is investigated using an analytical model. Particles are assumed to reach their equilibrium size and density upon entering the trachea from either the nasal or oral pharyngeal compartments. Calculated data are used to describe the equilibrium values for specified relative humidity conditions which simulate the atmosphere, inhalation exposure chambers, and the lung. Theoretical equations are used to calculate aerosol deposition efficiencies within conducting airways of the tracheobronchial tree. Hygroscopic growth is shown to affect both the total dose deposited and its regional distribution. For an inspiratory flow rate of 30 L min-1, the total deposition efficiency of H2SO4-and-H2O droplets, resulting from water condensation upon H2SO4 particles of initial geometric diameter D0, is greater than inspired nonhygroscopic particles of identical aerodynamic diameter when D0 greater than 0.1 mu m. The opposite is found when D0 less than 0.1 mu m. The effects of hygroscopic growth are explained in terms of the changing deposition efficiencies of the inertial impaction, sedimentation and diffusion mechanisms. Results imply that it is important that hygroscopic growth within the human respiratory tract be accounted for when assessing the potential health hazard of airborne particulate matter.

The incidence of selected vaginal infections among pregnant urban blacks

A total of 232 Black antenatal patients was assessed in a cross-sectional study and a total of 80 in a longitudinal study. Trichomonas vaginalis infection occurred almost twice as frequently as Candida albicans infection. Neisseria gonorrhoeae infection was present in 10% of patients, and mixed infections were present in 34% of patients.

Rhinorrhea associated with intracranial cholesteatomas and an "empty sella."

Three related disorders in the same patient, namely bilateral primary intracranial cholesteatomas, an "empty sella" syndrome, and a cerebrospinal rhinorrhea are reported. No previous report of bilateral symmetrical cholesteatomas has been made, though single intracranial cholesteatomas have frequently been recorded in medical literature. The "empty sella" syndrome is generally considered to be from a herniation of the subarachnoid into the sella through a deficient diaphragma sella, and was first defined by Ommaya in 1968. Non-traumatic (spontaneous) rhinorrhea remains an uncommon disease initially described in 1826. Experience of the individual otolaryngologist is limited in this region because of infrequent occurrence and because definitive treatment is directed to other specialties. On the other hand, the ear, nose and throat physician may be the first to interpret a drainage from the nose. With this in mind, the etiologic, clinical and management factors in the present case are discussed.

Effects of the health service and environmental factors on infant mortality: the case of Sri Lanka

One of the findings of this study is that regional variations in the infant mortality rates of Sri Lanka are large, ranging from 26 per 1000 live births in Jaffna to 91 per 1000 in Nuwara Eliya, a tea estate district. These differences are more strongly associated with regional variations in environmental determinants of mortality than with regional variations in public health expenditure. The most significant environmental factor associated with interregional infant mortality rates was to be the nature of the water supply (r = -0.82, significant at the 99% level). Regional government expenditure on health had only a weak association with infant mortality rates (r = 0.08).

Hydroheptin: a water-soluble polyene macrolide. II. Chemical and biological properties

Hydroheptin, a new polyene macrolide antifungal antibiotic, is co-produced with the antibiotic, chartreusin, by a strain of Streptomyces chartreusis designated as IMRU 3962 isolated in our laboratory. The unique water-solubility of this antibiotic at neutrality, revealing in aqueous solution molecular dispersion and an ultraviolet-visible absorption spectrum characteristic of an all-trans heptaene chromophore, clearly distinguishes it from all previously-described and naturally-occurring heptaene macrolides. The isolation and identification of the amino sugar, mycosamine (3-amino-3,6-dideoxy-D-mannose), in acid hydrolysates of hydroheptin and the absence of an aromatic amine upon retrograde alkaline dealdolization of the molecule certainly characterize the antibiotic as a member of the non-aromatic heptaene macrolide group. Chromatographic and countercurrent distribution studies likewise support its novelty. With little or no demonstrable activity against bacteria, hydroheptin as compared to other non-aromatic heptaene macrolides exhibits excellent but somewhat less activity against a wide variety of yeasts and fungi. Likewise, its parenteral toxicity appears to be less than that of other heptaene macrolides.

Biosynthetic pathway leading to gentamicin C2b

Incubation of Micromonospora purpurea SC 1210 (NRRL 5467) with L-[methyl-14C]methionine yielded [methyl-14C]gentamicin A and methyl-14C-labeled antibiotic JI-20A in a molar radioactivity ratio of 9:2. We did not isolate methyl-14C-labeled gentamicin X2, which was expected as an intermediate based on the biosynthetic pathways proposed by others. Addition of methyl-14C-labeled antibiotic JI-20A to M. purpurea SC 1124 (NRRL 8102) yielded [methyl-14C]-gentamicin C1a and [methyl-14C]gentamicin C2b in variable molar radioactivity ratios. These data do not support the biosynthetic pathway leading to gentamicin C2b proposed by Testa and Tilley.

Conduction disturbances in patients with calcified mitral annulus diagnosed by echocardiography

Clinical, radiologic and histo-pathological observations have suggested that conduction disturbances (CD) are frequent in patients with calcified mitral annulus (CMA). To determine the incidence of CD, 65 consecutive patients with CMA were studied. Sixty-five normal individuals, matched for age and sex served as a control group. CMA has been identified by M-mode echocardiography, cross-sectional echo and image amplifier fluoroscopy. CD were present in 23 patients with CMA as compared to seven patients in the control group (p less than 0.01). Three patients developed complete atrioventricular block (4.6%) during hospitalization requiring artificial pacemakers. We conclude that, 1) early detection of CMA in the elderly is useful in predicting a higher incidence of CD. 2) Complete heart block is more frequent in patients with CMA. 3) Frequent ECG follow-up in these patients has proven to be useful in avoiding serious clinical complications.