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Biomedical subjects

J J Zimmerman

Publications and source records attributed to J J Zimmerman.

At least 19 recordsLinked to original sources
PubMed1992

Detection of enhanced neutrophil adhesion to parainfluenza-infected airway epithelial cells using a modified myeloperoxidase assay in a microtiter format.

Despite growing evidence that respiratory virus infections precipitate episodes of airway obstruction and airway hyper-responsiveness in young children and in asthma, little information is available on the mechanisms by which virus infections alter the airway physiology. Airway inflammatory changes (including influx of inflammatory cells such as neutrophils) have been described during episodes of airway hyper-responsiveness in both animal models and human subjects. Neutrophil damage to several cell types has been shown to require adhesion as a primary step. In order to examine the potential interactions between virus-infected airway epithelial cells and neutrophils, we have studied the ability of neutrophils to adhere to virus-infected airway epithelial cell cultures. Neutrophil adherence was determined indirectly, using myeloperoxidase as a marker for adherent neutrophils in an assay system described here. Airway epithelial cell cultures (both primary human tracheal epithelial cells, and two permanent cell lines, A549 and BEAS-2B) were grown in 96-well tissue culture plates and infected with human parainfluenza virus type 2. Infected airway epithelial cell cultures supported significantly enhanced levels of neutrophil adherence (up to 50-75% of neutrophils added to the wells) compared to uninfected control cultures. Moreover, this adherence occurred in a virus dose-dependent fashion, with increasing levels of adherence noted at increasing viral multiplicities of infection. The assay system described allows the detection of small numbers of adherent neutrophils (as few as 1000 neutrophils) in a 96-well format.

Bronchi↗
PubMed1992

The epidemiology of toxoplasmosis on Iowa swine farms with an emphasis on the roles of free-living mammals.

Multiparous sows from 19 central Iowa swine farms were tested for antibodies against Toxoplasma gondii by the modified direct agglutination test. Antibody titers of 1:32 or greater were considered positive. Rodents, domestic cats, opossums (Didelphis virginiana), raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) were live-trapped on each farm and similarly tested for antibodies. The overall prevalence of T. gondii antibodies in the species tested was 39/273 (14.3%) swine, 31/74 (41.9%) cats, 2/588 (0.3%) house mice (Mus musculus), 0/21 mice of the genus Peromyscus, 0/9 Norway rats (Rattus norvegicus), 1/34 (2.9%) opossums, 4/14 (28.6%) raccoons and 2/7 (28.6%) striped skunks. The overall prevalence was significantly greater in adult cats versus juvenile cats, adult male cats versus adult female cats, and adult raccoons versus juvenile raccoons. The prevalence of T. gondii antibodies in sows was compared with the prevalence in each non-swine species on a farm basis in order to identify existing associations. The prevalence in sows (and each of the non-swine species) was also analyzed on a farm basis for association with farm characteristics or swine management practices, including the degree of confinement of swine, population size and average parity of breeding female swine, estimated cat population size, and estimated mouse and rat abundance. Average titers of seropositive animals were compared on a species basis. The prevalence in sows which were totally and continuously confined was lower than that in sows which were not totally and continuously confined. The prevalence in sows from farms with an average parity of less than 2.0 was significantly lower than that in sows from farms with an average parity of 2.0 or greater. These results suggested that the prevalence of T. gondii antibodies in swine increased with age and that prevalence in swine could be reduced through total confinement. No associations could be established between prevalence in sows and prevalence in non-swine species or other farm characteristics/swine management practices. However, the high prevalence of T. gondii antibodies in cats suggested that fecal contamination of the environment by cats may be the most significant source of toxoplasmosis for swine. The extremely low prevalence of T. gondii antibodies in house mice suggested that this species was not an important source of T. gondii for swine in Iowa.

Animals↗
PubMed1992

Activated neutrophils inhibit Na(+)-K(+)-ATPase in canine renal basolateral membrane.

To examine the effects of activated neutrophils (PMNs) on Na(+)-K(+)-ATPase, phorbol 12-myristate 13-acetate (PMA)-stimulated PMNs were incubated with canine renal cortical basolateral membrane (BLM), and BLM ouabain-sensitive Na(+)-K(+)-ATPase activity was subsequently quantified. Na(+)-K(+)-ATPase activity decreased to 40.0 +/- 8.7% (SE) of control in the presence of activated PMNs, from 0.89 +/- 0.12 to 0.34 +/- 0.05 mumol Pi.mg protein-1.min-1. This inhibition coincided with a decrease in the apparent Michaelis constant (Km) for ATP from 0.18 +/- 0.02 to 0.05 +/- 0.01 mM. Inclusion of catalase (CAT) and superoxide dismutase (SOD) in the BLM/PMN/PMA incubation mixture resulted in partial preservation of enzyme activity, with an increase to 57.0 +/- 4.6% of control with CAT alone and to 70.0 +/- 5.3% with both CAT and SOD. SOD alone had no protective effect. Neither the myeloperoxidase inhibitor azide nor the hypochlorous acid scavenger L-methionine preserved enzyme activity. Hydroxyl radical scavengers and iron chelators were also ineffective in attenuating Na(+)-K(+)-ATPase inhibition by activated PMNs. These results indicate that activated PMNs mediate a decrease in BLM Na(+)-K(+)-ATPase activity characterized by a reduction in maximum velocity and Km for ATP that appears to be mediated in part by reactive oxygen metabolites.

Animals↗
PubMed1992

Inflammatory host responses in sepsis.

Although microbes and their associated toxins initiate sepsis, it is the subsequent host inflammatory response that defines most of what we characterize as clinical sepsis. This article considers the various cellular as well as humoral mediators involved in this response in addition to the complex networking that may result in both augmentation and modulation of the inflammatory response in sepsis.

Biological Factors↗
PubMed1991

Seroprevalence of antibodies against encephalomyocarditis virus in swine of Iowa.

A total of 2,614 swine from 104 herds located throughout Iowa were tested for antibodies against encephalomyocarditis virus (EMCV) by use of the microtitration serum neutralization test. The sample was composed of 587 sows and gilts and 2,027 finishing swine. A statistically significant (P less than 0.002) difference was observed between prevalence in sows and gilts (17.2%) and that in finishing swine (12.2%). Breeding swine maintained in total confinement (20.5%) had significantly (P = 0.04) higher prevalence than did breeders maintained in other types of housing (12.1%), whereas prevalence in finishing swine raised in total confinement (6.4%) was significantly (P = 0.02) lower that in finishers not raised in total confinement (13.6%). Association was not detected between prevalence and herd size or between prevalence and season of the year. Adjusting for test specificity and sensitivity, the true prevalence of EMCV infection in swine in Iowa was estimated to be 13.8% in breeding stock and 8.5% in finishing swine. On a herd basis, 89.4% (93/104) of the herds had one or more EMCV-positive swine.

Animals↗
PubMed1991

Activated polymorphonuclear leukocytes inhibit phosphatidylcholine synthesis in cultured type II alveolar cells.

Activated human neutrophils (PMNs) were demonstrated to inhibit total de novo phosphatidylcholine (PC) synthesis in monolayered rat alveolar type II cells (T2C). Non-activated PMNs had no effect on PC synthesis in this system. The magnitude of inhibition T2C PC synthesis by phorbol myristate acetate-activated PMNs in six experiments averaged 59.0 +/- 13%. Exogenous chelated iron (ferric pyrophosphate) did not appear to augment the PMN-mediated inhibition of T2C PC production in this model. Alpha-1-antiprotease usually provided no protection relative to the PMN insult towards the T2C. However, superoxide dismutase and catalase alone or in combination generally provided a significant, protective effect. Although activated PMNs consistently decreased T2C PC synthesis, this effect did not appear to involve generalized T2C cytotoxicity, as assessed by lack of release of cytosolic lactate dehydrogenase. These results indicate that PMNs can inhibit T2C PC synthesis in vitro, probably via oxyradical injury. This type of pulmonary host autoinjury may be operative in a variety of acute lung injury syndromes involving pulmonary sequestration of activated PMNs.

Acute Disease↗
PubMed1991

Reflex sympathetic dystrophy--the surgeon's role in management.

It is important for vascular surgeons to be familiar with reflex sympathetic dystrophy because they may be called on to participate in the evaluation and treatment of patients with this syndrome. Over a 3 1/2-year period, 35 patients, initially evaluated by a team of pain experts, were referred for surgical sympathectomy for reflex sympathetic dystrophy. All patients had at least one positive diagnostic sympathetic block before they were considered for surgical sympathectomy. With use of this team approach and careful patient selection, excellent results were obtained in 74%, good results in 17%, and poor results in 9%. Three patients required a repeat cervical sympathectomy after initial surgery failed to relieve their symptoms. One patient required a contralateral lumbar sympathectomy after ipsilateral sympathectomy was unsuccessful. Better results were obtained in patients treated earlier in their course and with extended surgical sympathectomy. Patients not responding to initial sympathectomy should be evaluated for the presence of residual functional sympathetic tissue, and if this is identified, further sympathectomy by an alternate approach appears justified.

Adolescent↗
PubMed1991

Human neutrophil elastase and elastase/alpha 1-antiprotease complex in cystic fibrosis. Comparison with interstitial lung disease and evaluation of the effect of intravenously administered antibiotic therapy.

In cystic fibrosis (CF), extracellular lung matrix is progressively damaged, neutrophils invade the air spaces, and activated neutrophils may release large amounts of neutrophil elastase (NE). Although alpha 1-antiprotease (alpha 1-AP) binds and inactivates NE and is the major antielastase of the lower respiratory tract, antielastase defenses may be overwhelmed in CF, leading to progressive lung damage. To determine whether the ability of alpha 1-AP to neutralize NE is impaired in CF, we compared NE activity in bronchoalveolar lavage (BAL) fluid and human neutrophil elastase/alpha 1-antiprotease (NE/alpha 1-AP) complex in both BAL fluid and peripheral blood serum from patients with CF, normal volunteers, and patients with interstitial lung disease. We detected a considerable amount of NE activity in BAL fluid from all but one patient with CF but none in that from normal volunteers or from patients with interstitial lung disease. Although in interstitial lung disease there was a significant correlation between increased NE/alpha 1-AP complex in BAL or peripheral blood and the degree of neutrophil influx, NE/alpha 1-AP complex was disproportionately low in CF BAL compared with significantly elevated values in serum. These data suggest that in CF, alpha 1-AP-mediated defense against free NE in the lower respiratory tract is significantly impaired, and high levels of uncomplexed, enzymatically active, NE are present in CF respiratory secretions. To determine whether intravenously administered antipseudomonal antibiotic therapy for exacerbations of CF lung disease diminished the amount of free NE in respiratory secretions, we used BAL to investigate the effect of such therapy on neutrophils and NE in patients with CF colonized with pseudomonads.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

In vitro phosphatidylcholine peroxidation mediated by activated human neutrophils.

Activated human polymorphonuclear leukocytes (PMNs) mediated peroxidation of dilinoleoyl phosphatidylcholine (DPLC) liposomes. Concentration-response effects were demonstrated for both PMNs and DLPC in the system studied. Chelated iron facilitated peroxidation threefold. Superoxide dismutase variably inhibited peroxidation, but never completely. Although O2-. synthesis ceased 30-40 min after PMN stimulation, lipid peroxidation continued for an additional 30-60 min, suggesting that PMNs may initiate peroxidation which subsequently becomes autocatalytic. Enhanced PMN-mediated DLPC peroxidation was noted in acidic media. Separation of DLPC reaction products by high pressure liquid chromatography demonstrated the de novo appearance of conjugated diene species. Preliminary specific ion monitoring mass spectroscopy analysis of gas chromatography fractions of reaction products (derivatized to fatty acid methyl esters/trimethylsilane hydroxyl ethers) indicated that PMN-generated oxyradicals resulted in production of conjugated 9- and 13-hydroperoxy DLPC derivatives. These results illustrate directly how activated PMNs may participate in host autoinjury by mediating phospholipid peroxidation.

Dose-Response Relationship, Drug↗
PubMed1990

Prevalence of toxoplasmosis in swine from Iowa.

Of swine from 104 herds, 2,616 were tested for antibodies against Toxoplasma gondii, using an ELISA. Data were analyzed according to swine type, herd size, facility type, and season. The true prevalence of toxoplasmosis was estimated as 5.4% among finishing swine and 11.4% among sows and gilts. Herds with less than 100 breeding swine were significantly (P less than 0.05) more likely to be infected than were herds with greater than or equal to 100 breeding swine. The rate of seropositivity in breeding swine was approximately the same in infected herds, regardless of herd size. Herds with finishing swine maintained in total confinement were as likely to become infected as were herds maintained in other types of facilities, but infected herds with finishing swine maintained in confinement appeared to have a lower in-herd prevalence than did herds maintained in other types of facilities (P = 0.09). Seasonal effects were not observed, and prevalence remained relatively constant throughout the year.

Age Factors↗
PubMed1990

The use of half-lives and associated confidence intervals in biological research.

The advantage of presenting experimental data in terms of half-life is discussed and a simple method of calculating a half-life from experimental data is described. Two methods of determining the confidence interval associated with the estimate of half-life are given and advantages and disadvantages of each method are discussed.

Analysis of Variance↗
PubMed1990

Retinol inhibition of in vitro human neutrophil superoxide anion release.

Retinol deficiency has been clinically associated with visual impairment as well as altered growth and differentiation of various epithelial cell populations. An additional factor that may be operative in the setting of retinol deficiency is impaired immunomodulation of the neutrophil inflammatory response. Our study demonstrated a concentration-dependent inhibition by retinol of activated neutrophil superoxide anion (O2.-) release. Concentration of drug (retinol) causing 50% inhibition of initial velocity O2.- production (IC50) was 42.6 +/- 10.9 microM. Latter phases of the O2.- release reaction displayed significantly lower IC50 values. Similarly, as time of retinol-neutrophil incubation was increased, IC50 decreased. Retinol inhibition of neutrophil O2.- did not appear to involve activation/desensitization, cytotoxicity, or free-radical scavenging mechanisms. Retinol was shown to inhibit intact PMN O2.- release even after addition of the respiratory burst stimulus. Moreover, retinol inhibited O2.- release in membranes isolated from activated neutrophils. In addition to promoting proper organization and differentiation of epithelial cells, appropriate plasma/tissue retinol levels may also modulate the neutrophil tissue inflammatory response.

Adult↗
PubMed1990

Survival of pseudorabies virus in aerosol.

The survival of pseudorabies virus in an aerosol was studied under different environmental conditions of temperature and relative humidity. Pseudorabies virus decayed logarithmically with mean half-lives of 17.4 (85% relative humidity, 22 C), 18.8 (25% relative humidity, 22 C), 27.3 (85% relative humidity, 4 C), 36.1 (55% relative humidity, 22 C), and 43.6 (55% relative humidity, 4 C) minutes. Virus survival was significantly improved in environments at 55% relative humidity, compared with those at 85% relative humidity (P = 0.017). Rates of survival were improved in environment at 4 C in comparison with those at 22 C. Results suggest that, under the best conditions of this study, the infectivity of pseudorabies virus in an aerosol decreases by 50% in less than 1 hour.

Aerosols↗