P1358 New insights into cardiac dysfunction assessed by left atrial function in patients with type 1 diabetes mellitus

BACKGROUND

There have been many reports of heart failure due to diabetic cardiomyopathy and decreased left ventricular (LV) function with increasing age in patients with type 1 diabetes mellitus (T1DM). Recently, although left atrial (LA) function has been occasionally reported to be a more useful prognostic indicator than LV function in acquired heart diseases, LA function in patients with T1DM has not yet been studied.

PURPOSE

To investigate LA dysfunction in patients with T1DM.

METHODS

Fifty patients with T1DM were recruited (age, 5–41 years). We excluded patients who had a history of heart disease, hypertension, and those taking cardioprotective agents. The patients and 50 age-matched controls were classified into 3 age groups (D1, C1, 5–14 years; D2, C2, 15–29 years; D3, C3, 30–41 years). The LA phasic function serving as the reservoir, conduit, and pump strains; the LA strain rate (SR) in the systole, early diastole, and late diastole; and the LV global longitudinal strain (LV-LS) as determined via 2-dimensional speckle tracking imaging were measured from the apical four- and two-chamber views. We also calculated the LA stiffness index as the ratio of E/e’ to the LA reservoir strain.

RESULTS

There was no significant difference in left ventricular ejection fraction in each age group. The LA reservoir strains in D2 and D3 were significantly lower than those in C2 (40.8 ± 5.7% vs. 47.2 ± 5.5%, p = 0.005) and C3 (39.2 ± 5.5% vs. 47.3 ± 5.7%, p = 0.004), respectively. The LA conduit strain in D2 was significantly lower than that in C2 (28.9 ± 5.8% vs. 35.0 ± 5.0%, p = 0.006). The LA pump strain and the three phases of LA SR were not significantly different among the age groups. The LA stiffness index in D3 increased significantly compared to that in N3 (0.18 ± 0.05 vs. 0.13 ± 0.01, p <0.001). The LV-LS in D2 and D3 was significantly lower than that in C2 (-15.7 ± 1.7% vs. -18.7 ± 2.1%, p <0.001) and C3 (-15.3 ± 1.8% vs. -19.3 ± 2.0%, p <0.001), respectively. The LA reservoir strain significantly correlated with LV-LS (r = -0.468, p < 0.001). Both the LA reservoir strain and LV-LS in patients with T1DM decreased significantly (p = 0.028, p < 0.042, respectively) and correlated with increasing age (r = -0.323, r = 0.286, respectively). The LV stiffness index did not correlate with age or LV-LS.

CONCLUSIONS

The LA reservoir strain might be as useful as LV-LS as an early marker of cardiac dysfunction in patients with T1DM. The correlation coefficient between the LA reservoir strain and LV-LS was not strong. Therefore, although LV-LS might affect the LA reservoir strain, it might represent other aspects of cardiac dysfunction. The increase of LA stiffness might represent the changes in LA wall properties and could be another useful indicator of cardiac dysfunction during long-term follow-ups, which is independent of LV-LS. Overall, these findings provide new insights into cardiac dysfunction in patients with T1DM.

[Effects of morphine, buprenorphine and butorphanol on airway dynamics of the rabbit]

An investigation was made on the effects of morphine, buprenorphine, and butorphanol on airway dynamics with special reference to the airway smooth muscle in rabbits. After tracheostomy under anesthesia, the animals were ventilated with a Servo 900B ventilator, and airway resistance (R) and total compliance (C) were measured according to the method of Norlander, and the effect of each drug was examined. Intravenous injection of morphine 0.2 mg.kg-1 increased R significantly at 10 and 20 minutes after its administration in nontreated animals and changed R insignificantly in animals pretreated with intravenous administration of chlorpheniramine 2.5 mg, an antihistaminic. It is considered that the increase in R after the administration of morphine in the nontreated animals is due to histamine release. Buprenorphine 0.8 micrograms.kg-1 and butorphanol 0.1 mg.kg-1 brought no significant changes in R in both nontreated and the chlorpheniramine pretreated animals. C decreased in all the groups including the control group which received mechanical ventilation alone without any drug administration.

Detection of Lea substance in saliva stains by enzyme-linked immunosorbent assay (ELISA) using anti-gum arabic serum

It is known that rabbit anti-gum arabic (GA) serum has cross-reactivity with Lea antigen, and that, by using this cross-reactive anti-Lea antibody, the presence of Lea antigen in red blood cells and saliva can be demonstrated with accuracy. We have devised a rapid and highly sensitive method for detecting Lea substance in human saliva by the enzyme-linked immunosorbent assay (ELISA) method using an anti-Lea antibody isolated from anti-GA serum by affinity chromatography on Synsorb Lea. The ELISA plate, coated with the specific anti-Lea antibody, adsorbed the Lea substance in saliva which was subsequently identified by adding enzyme labeled anti-Lea IgG in that order. The method could detect the Lea substance in Le(a+) saliva stains as small as 0.1 by 0.1 cm in size that had been stored at room temperature for three weeks and in Le(a+) saliva stains 0.7 by 0.7 cm in size that had been stored for ten years. This method seems to be useful for quantitative analyses of the Lea substance in various body fluids.

Identification of blood groups and isoenzymic phenotypes from blood stains, heart blood and nervous tissues after transfusion

A man aged 42 years died from a hemorrhage resulting from stab wounds in his neck, chest and abdomen. The MN blood group and PGM1 phenotype of the victim's heart blood were inconsistent with those of the blood stains around the victim. The victim was transfused with 4000 ml of blood during the 9 hours before his death. Because PGM1 phenotypes obtained from blood stains at the scene of the crime and from the weapon corresponded with those from the victim's dental pulp, peripheral nerve and bone marrow, the victim's blood groups and isoenzymic phenotypes could be determined accurately.