Effect of methyl parathion on the susceptibility of shrimp Litopenaeus vannamei to experimental vibriosis.

Following increasing calls for environmental safety over the past 2 decades, persistent pesticides are being replaced by more rapidly degradable products. However, even these pesticides can affect non-target species, and may be associated with slow growth and increased susceptibility to viral and bacterial infections. In this study, juvenile white shrimp Litopenaeus vannamei (also named Penaeus vannamei) were challenged by intramuscular injection with Vibrio parahaemolyticus after 4 d prior exposure to methyl parathion in feed pellets at 0.080 microg g(-1). The bacterial injection control group consisted of shrimp fed pellets containing the methyl parathion-carrier solvent acetonitrile. Three additional control groups comprised 2 sterile saline-injection groups fed pellets containing methyl parathion or acetonitrile prior to injection, and 1 uninjected group fed normal pellets. Cumulative mortalities were recorded on the 4th and 8th days, and the presence of histological lesions was recorded on the 8th day. Cumulative mortalities were significantly higher in the group exposed to methyl parathion and bacteria on Day 8. Histological lesions, typical of vibriosis, were significantly associated with the injection of V. parahaemolyticus. The study provides strong experimental evidence that prior exposure to methyl parathion can increase the severity of Vibrio infections.

Hydrolysis of 4-hydroxybenzoic acid esters (parabens) and their aerobic transformation into phenol by the resistant Enterobacter cloacae strain EM.

Enterobacter cloacae strain EM was isolated from a commercial dietary mineral supplement stabilized by a mixture of methylparaben and propylparaben. It harbored a high-molecular-weight plasmid and was resistant to high concentrations of parabens. Strain EM was able to grow in liquid media containing similar amounts of parabens as found in the mineral supplement (1,700 and 180 mg of methyl and propylparaben, respectively, per liter or 11.2 and 1.0 mM) and in very high concentrations of methylparaben (3,000 mg liter(-1), or 19.7 mM). This strain was able to hydrolyze approximately 500 mg of methyl-, ethyl-, or propylparaben liter(-1) (3 mM) in less than 2 h in liquid culture, and the supernatant of a sonicated culture, after a 30-fold dilution, was able to hydrolyze 1,000 mg of methylparaben liter(-1) (6.6 mM) in 15 min. The first step of paraben degradation was the hydrolysis of the ester bond to produce 4-hydroxybenzoic acid, followed by a decarboxylation step to produce phenol under aerobic conditions. The transformation of 4-hydroxybenzoic acid into phenol was stoichiometric. The conversion of approximately 500 mg of parabens liter(-1) (3 mM) to phenol in liquid culture was completed within 5 h without significant hindrance to the growth of strain EM, while higher concentrations of parabens partially inhibited its growth.

Development of an ED teaching program aimed at reducing prehospital delays for patients with chest pain.

OBJECTIVE: Delays in providing thrombolytic agents to patients with chest pain occur mainly in the prehospital arena. To reduce prehospital delay in treating patients with chest pain, we created a discharge teaching video that emphasized calling 911 in the event of a possible heart attack and a written action plan to be posted near the telephone. We also gave patients their EKG readings to bring with them on their next visit to the emergency department. SETTING AND SAMPLE: All patients with chest pain admitted to the Chest Pain Observation Unit at Baystate Medical Center, Springfield, Mass, were eligible for this teaching effort. We tracked 127 nonconsecutive patients from January 1997 to May 1997. Of these patients, 108 were included in the study. RESULTS: We interviewed 102 patients (94%) 3 days after they were discharged from the Chest Pain Observation Unit. Within this group, 92% were able to describe what a heart attack might feel like, and 81.4% said they would call 911 or go to the hospital if they had symptoms of a heart attack. If they thought that their symptoms might be indigestion, 69% said they would take an antacid, then go to the hospital if they did not feel better. Fifty-one percent remembered what to do with their EKG readings, and 60.7% knew how to take their nitroglycerin correctly. CONCLUSION: We concluded that patients understood the message they were given and retained some of the material 3 days after discharge from the Chest Pain Observation Unit. The follow-up telephone calls revealed areas for improvement in the discharge teaching tools.

Automated in-vivo measurement of quasi-static lung compliance in the rat.

Instrumentation to automate quasi-static lung compliance measurement in the rat was developed and values obtained with it were compared with manual measurements by a trained technician. Designed to be used during mechanical ventilation, this system interrupts ventilation to inflate and deflate the lungs and measures lung transmural pressure and volume as functions of time. Animal experiments demonstrated that the automated system is capable of generating correctly shaped volume-pressure curves. These curves yielded reproducible lung compliance values that compare favorably with those obtained by the manual method. No statistically significant difference was observed comparing the two methods when evaluating either inter- or intra-animal variation. This automated system thereby obviates the need for highly trained personnel to perform the test.

HLA antigens-linked genetic control in multiple sclerosis patients resistant and susceptible to infection.

Patients with multiple sclerosis (MS) from the two Montreal MS clinics, were divided into two groups: one group of 61 patients (MS type I) who had no clinical history of susceptibility to recurrent respiratory tract infections and a second group of 58 patients (MS type II) who had persistent susceptibility to such infections since childhood. All patients were typed for the HLA tissue antigens. The HLA antigen frequencies of the total MS patient population, and of MS type I and MS type II patients were compared to those of a normal control population and each other. The HLA-DR2 and B7 antigen frequencies were significantly increased compared to the normal controls for all MS patients. MS type I patients had an increased frequency for HLA-Bw42 and DRw8 antigens; the frequency of HLA-A29 was lower than in the controls and MS type II patients. MS type II patients had a significantly increased frequency for DR3 and some HLA-DR3-associated phenotypes (A1 + DR3; B8 + DR3; A1 + B8 + DR3) as compared to controls and MS type I patients. These results are consistent with the existence of genes linked to the HLA antigens, such as immune response genes, which control the resistance or susceptibility of the patients to infection, and suggest that these HLA antigens could be associated with a difference in the evolution of MS, as observed in the MS type I and II patients [21].