Ecological determinants for germination and growth of some Aspergillus and Penicillium spp. from maize grain

This study compared the effect of temperature (5-45 degrees C), water availability (water activity, aw; 0.995-0.75) and their interactions on the temporal rates of germination and mycelial growth of three mycotoxigenic strains of Aspergillus ochraceus and one isolate each of A. flavus, A. niger, Penicillium aurantiogriseum and P. hordei in vitro on a maize extract medium. Germination was very rapid at > 0.90 aw with an almost linear increase with time for all species. However, at < 0.90 aw, the germination rates of A. flavus and P. hordei were slower. The aw minima for germination were usually lower than for growth and varied with temperature. The effect of aw x temperature interactions on the lag phases (h), prior to germination, and on the germination rates (h(-1)), were predicted for the first time for these fungi using the Gompertz model modified by Zwietering. This showed that A. flavus, A. niger and the two Penicillium spp. had very short lag times between 0.995-0.95 aw over a wide temperature range. At marginal temperatures, these were significantly higher, especially at < 10 degrees C for Aspergillus spp. and > 30 degrees C for Penicillium spp. There were also statistically significant differences between lag phases and germination rates for three different isolates of A. ochraceus. The Aspergillus spp. also germinated faster than the Penicillium spp. The temperature x aw profiles for mycelial growth varied considerably between species, both in terms of rates (mm d(-1)) and tolerances. Predictions of the effects of important environmental factors such as temperature, aw and their interactions on lag times to germination, germination rates and mycelial growth are important in the development of hurdle technology approaches to predicting fungal spoilage in agricultural and food products.

[Endoscopic coagulation with argon plasma, a therapeutic option in gastric antral vascular ectasia]

BACKGROUND

Gastric Antral Vascular Ectasia or Watermelon stomach is a rare cause of chronic gastrointestinal bleeding, often presenting as a chronic iron deficiency anemia. This condition can be associated with some other diseases such as cirrhosis, autoimmune diseases and others. We report two patients treated with Argon Plasma Coagulation, a 68 years old male with an ethanol related cirrhosis and a 72 years old female with an idiopathic Gastric Antral Vascular Ectasia. The characteristic endoscopic features were mistaken for many years as gastritis. Both patients presented with severe anemia requiring multiple transfusions as treatment. Due to the poor operative risk, both patients were treated with Argon Plasma Coagulation with good results.

[Interleukin-6 and interferon-gamma release from blood mononuclear cells and colonic mucosa from patients with ulcerative colitis]

BACKGROUND

Cytokines are involved in the pathogenesis of inflammatory bowel diseases such as ulcerative colitis and Crohn disease.

AIM

To measure cytokine release by mononuclear cells of patients with ulcerative colitis.

PATIENTS AND METHODS

Twelve patients subjected to a diagnostic colonoscopy were studied. Six had an ulcerative colitis and six did not have inflammatory changes in the colonic mucosa and were considered as control. Mononuclear cells were isolated from biopsies of colonic mucosa and from peripheral blood cultivated during 48 hours with pokeweed mitogen, and Interleukin 6 and interferon-gamma were measured in their supernatants.

RESULTS

In patients with ulcerative colitis, interleukin 6 secretion by peripheral blood mononuclear cells was higher than in control subjects in the basal period (2212 +/- 424 and 443 +/- 174 pg/ml respectively p = 0.03) and after stimulation with pokeweed mitogen (16,328 +/- 1275 and 5462 +/- 322 pg/ml respectively p = 0.03). No differences in interleukin 6 secretion by colonic mucosa mononuclear cells were observed. Unstimulated cells did not liberate interferon-gamma. The secretion of this lymphokine by stimulated colonic mucosa cells was lower in patients with ulcerative colitis than in controls (1571 +/- 216 and 7953 +/- 389 pg/ml respectively p = 0.03).

CONCLUSIONS

Local and systemic changes in interleukin 6 and interferon-gamma secretion occur in patients with ulcerative colitis. These changes could be related to the development of the disease.

Post-disaster malaria in Costa Rica

INTRODUCTION

In recent years, controversy has surrounded the issue of whether infectious disease should be considered a serious potential consequence of natural disasters. This article contributes to this debate with evidence of a significant outbreak of malaria in Costa Rica's Atlantic region after the 1991 earthquake and subsequent floods.

METHODS

This study is an epidemiologic investigation of the incidence of malaria for the periods of 22 months before the April 1991 Limón earthquake and for 13 months afterward. Data were obtained from the Costa Rican Ministry of Health's malaria control program.

RESULTS

Some of the cantons in the region experienced increases in the incidence of malaria as high as 1,600% and 4,700% above the average monthly rate for the preearthquake period (p < or = 0.01). Causal mechanisms are postulated as relating to changes in human behavior (increased exposure to mosquitoes while sleeping outside, and a temporary pause in malaria control activities), changes in the habitat that were beneficial to mosquito breeding (landslide deforestation, river damming, and rerouting), and the floods of August 1991.

CONCLUSIONS

It is recommended that there be enhanced awareness of the potential consequences of disaster-wrought environmental changes. Date of Event: 22 April 1991; Type: Earthquake, 7.4 Richter scale;

LOCATION

Costa Rica; Number of deaths and casualties: 54 deaths and 505 moderate to severe injuries.