Effects of desflurane, sevoflurane and halothane on postinfarction spontaneous dysrhythmias in dogs.

BACKGROUND: Although desflurane (DES) and sevoflurane (SEV) have desirable features for use in patients with coronary artery disease, their effects on ventricular dysrhythmias following infarction are less known. We therefore examined the effects of DES and SEV upon spontaneous postinfarction ventricular dysrhythmias in dogs, and compared those effects to the well-established antidysrhythmic effects of halothane (HAL) in this model. METHODS: After institutional approval, the left anterior descending coronary artery was ligated in 16 adult mongrel dogs during isoflurane anesthesia. All dogs developed acute myocardial infarction and severe ventricular tachydysrhythmias. Twenty-two hours after infarction, dogs were anesthetized at 1.5 MAC with desflurane (10.8%) followed by sevoflurane (3.5%) in the treatment group (n = 10), or halothane (1.3%) in the other group (n = 6). Anesthetic gases were allowed to equilibrate for at least 20 min at each end-tidal concentration. At this time, the ECG was recorded for 9 min and evaluated for the number of ventricular ectopic and sinoatrial beats and summed duration of ventricular tachycardia. RESULTS: DES and SEV reduced the average rate of total ventricular ectopic beats by 40 +/- 4% and 42 +/- 4%, respectively. HAL decreased total ventricular ectopic rate by 59 +/- 6% and 62 +/- 5% after durations of anesthesia comparable to DES and SEV, respectively. Decreases in dysrhythmia in the presence of DES and SEV were significantly smaller than those produced by HAL after a comparable total duration of anesthesia. CONCLUSION: DES and SEV inhibit spontaneous postinfarction ventricular dysrhythmias, although attenuation of dysrhythmias was smaller than the inhibition during comparable doses of HAL.

Leptospires in Rattus spp. on Barbados.

Among 138 Rattus norvegicus and 98 R. rattus trapped on Barbados in 1964-65 and examined for evidence of leptospiral infection, seropositivity prevalence rates were similar (34 and 30%, respectively), but isolation/dark field microscopy rates were higher in R. norvegicus (27%) than R. rattus (15%). R. norvegicus carried mainly serogroup Icterohaemorrhagiae and R. rattus mainly serogroup Autumnalis. These two serogroups cause 90% of severe human leptospirosis on the island.

Leptospires in Rattus spp. on Barbados

Among 138 Rattus norvegicus and 98 R.rattus trapped on Barbados in 1964-65 and examined for evidence of leptosporal infection, sero-positivity prevalence rates were similar (34 and 39 percent, respectively), but isolation/dark field microscopy rates were higher in R. norvegicus (27 percent) than R. rattus (15 percent). R. norvegicus carried mainly serogroup Autumnalis. These two serogroups cause 90 percent of severe human leptospirosis on the island. (AU)

Pathogenic leptospira isolates from the Caribbean Island of Barbados

This paper lists all the known pathogenic leptospira isolates made on Barbados up to December 31, 1981. Only 17 of the total of 78 have already been reported on. The 78 isolates were obtained from humans, dogs, rats, mongooses and a mouse, and the serogroups to which they belonged were Icterohaemorrhagiae, Autumnalis, Ballum and Canicola. On Barbados, serogroup Autumnalis is an important human pathogen, and rats are an important reservoir of leptospires. The investigation and isolation of leptospires on Barbados has until recently been sporadic, dependent on the interst and enthusiasm of a few individuals, and restricted by a shortage of money and manpower. During 1964 and 1965 the Barbados Ministries of Health and Agriculture and the U.K. Ministry of Overseas Development investigated the impact of rodents on the health and economy of Barbados. As part of this study, leptospires wer isolated by taylor and identified to serogroup by Turner. The results are recorded in an unpublished document (Taylor, 1965). Between 1971 and 1981, Leptospira were isolated from rodents, mongooses (Herpestes auropunctatus), dogs and amphibians at the Barbados Veterinary Diagnostic Laboratory (VDL) by Jones and Everard. Twenty-three of these isolates survived and were identified by Myers and Dr. C. R. Sulzer of the Centers for Disease Control (CDC), Atlanta, U.S.A. Seventeen of the 23 have been reported on(Jones, 1974; Myers and Jones, 1975; Damude et al., 1979a), and they are included here for the sake of completeness. In 1979 10 Autumnalis isolates made by Taylor in 1964-1965 were reactivated from liquid nitrogen, cultured, and identified to serovar by Everard. The identifications were confirmed by Dr. Sulzer. The remaining 33 isolates in Taylor's series were not reactivated. From November 1979, isolates were made by Everard from patients at Queen Elizabeth Hospital (QEH), Bridgetown, and were identified to serovar by Dr. Sulzer. These studies have provided all the isolates recorded here. The Leptospiral Serotype DistributionList (Galton, 1966) do not have an entry for Barbados, but the supplement to the 1966 edition covering the period July 1966 to July 1973 (Sulzer, 1975) lists Autumnalis fort-bragg isolated from a rat, and Canicola, Ballum and Icterohaemorrhagiae from specified hosts. Barbados obtained up to December 31, 1981. Only 17 of the isolates have been previously reported. All the Leptospira isolates recorded from Trinidad, Grenada and St. Vincent up to the end of 1979 are listed by Everard et al. (180). (AU)

Research needs in leptospirosis.

Leptospirosis is a widespread infection of man and animals, and locally it assumes considerable importance as a public health and economic problem. It is an important occupational infection among persons working with animals or in environments that may be contaminated by infected animals. In recent years, considerable attention has been devoted to this infection but efforts to control and eliminate it, especially from natural foci, are hindered by gaps in our knowledge. This memorandum is a review of recent progress and current problems in leptospirosis research, with special reference to taxonomy, epidemiological methods, and control measures. Certain aspects of the basic biology of leptospires that are relevant to these topics are also discussed.