Milliseconds In Group Research Articles

Efficacy of 2 Different Intratympanic Steroid Regimen on Prevention of Cisplatin Ototoxicity: An Experimental Study

Ototoxicity is the general name of cochlear and vestibular organ injury resulting from encountering various therapeutic agents and chemical substances. Cisplatin is commonly used in the treatment of many cancers. In this study, the efficacy of intratympanic steroids was compared for preventing cisplatin ototoxicity. In this study, 32 (64 ears) rats were used by separating into 4 groups. Cisplatin was administered intraperitoneally to the first group (n = 8). Methylprednisolone and then cisplatin were administered intratympanically to the second group (n = 8). On the third group (n = 8), dexamethasone and then cisplatin were administered intratympanically. To the fourth group (n = 8), 0.9% NaCl and then cisplatin were given intratympanically. Otoacoustic emission (OAE) measurements and auditory brainstem responses (ABRs) tests were performed on all groups before and 72 hours after the procedure. Pretreatment of ABR-IV values were 4.29 ± 0.19 milliseconds in group 2 and 4.27 ± 0.16 milliseconds in group 3, whereas posttreatment ABR-IV values were 4.95 ± 0.35 milliseconds in group 2 and 4.65 ± 0.26 milliseconds in group 3. The ABR-IV values were measured significantly shorter in the rats given dexamethasone and methylprednisolone, according to control and cisplatin groups (P < .001). Pretreatment of ABR I-IV interval values were 2.98 ± 0.34 milliseconds and 3.03 ± 0.42 milliseconds in group 1 and group 4, respectively, and ABR I-IV interval values in group 1 and group 4 posttreatment were 3.49 ± 0.39 milliseconds and 3.5 ± 0.39 milliseconds in group 1 and group 4, respectively. Auditory brainstem responses I-IV interval was significantly longer in the cisplatin and control group than in the rats given dexamethasone and methylprednisolone (P < .001). After cisplatin treatment, OAE amplitudes decreased significantly in group 1 and group 4 for all frequencies, while OAE values were protected in methylprednisolone and dexamethasone group (P < .001). In conclusion, it has been shown that both agents have protective effects on cisplatin ototoxicity, with dexamethasone slightly more than methylprednisolone.

Atrial pacing site and atrioventricular conduction in patients paced for sinus node disease.

Unnecessary ventricular pacing in sinus node disease (SND) must be avoided. To test the hypothesis that in SND, with or without 1st degree atrioventricular (AV) block, cumulative percent ventricular pacing (cum%VP) can be limited by low right atrial septal (LRAS) instead of right atrial appendage (RAA) pacing. We studied 102 dual-chamber pacemaker recipients with SND. The PQ interval on 12-lead electrocardiogram and the atrial paced to ventricular sensed interval (Ap-Vs) during LRAS and RAA pacing were measured and compared at implantation, 3 months and 1 year of follow-up. Group 1 included 62 patients with baseline PQ interval <200milliseconds during LRAS (n = 28) versus RAA (n = 34) pacing. Group 2 included 40 patients with baseline PQ ≥200 milliseconds during LRAS (n = 20) versus RAA (n = 20) pacing. cum%VP were measured at 3 months and 1 year. The characteristics and AV conduction properties were similar and the Ap-Vs interval was significantly shorter in the LRAS than in the RAA pacing group up to 1 year (193 ± 32 milliseconds vs. 220 ± 27 milliseconds in Group 1; P = 0.003, 222 ± 41 milliseconds vs. 281 ± 30 milliseconds in Group 2; P < 0.001). While cumulative percent atrial pacing was consistently similar, cum%VP was significantly smaller during LRAS than RAA pacing (1 ± 1% vs. 8 ± 18% in Group 1; P = 0.03, 7 ± 10% vs. 48 ± 38% in Group 2; P < 0.001). Similar observations were made with or without left atrial (LA) enlargement. Compared with RAA, LRAS pacing showed shorter AV interval in SND patients with or without 1st degree AV block and LA enlargement. This beneficial effect persisted through 1-year follow-up, and decreased cum%VP significantly.

RELEASE AND VELOCITY OF MICRONIZED DEXAMETHASONE IMPLANTS WITH AN INTRAVITREAL DRUG DELIVERY SYSTEM

Ozurdex, a novel dexamethasone (DEX) implant, is released by a drug delivery system into the vitreous cavity. We analyzed the mechanical release aperture of the novel applicator, obtained real-time recordings using a high-speed camera system and performed kinematic analysis of the DEX application. Experimental study. : The application of intravitreal DEX implants (6 mm length, 0.46 mm diameter; 700 μg DEX mass, 0.0012 g total implant mass) was recorded by a high-speed camera (500 frames per second) in water (Group A: n = 7) or vitreous (Group B: n = 7) filled tanks. Kinematic analysis calculated the initial muzzle velocity as well as the impact on the retinal surface at approximately 15 mm of the injected drug delivery system implant in both groups. A series of drug delivery system implant positions was obtained and graphically plotted over time. High-speed real-time recordings revealed that the entire movement of the DEX implant lasted between 28 milliseconds and 55 milliseconds in Group A and 1 millisecond and 7 milliseconds in Group B. The implants moved with a mean muzzle velocity of 820 ± 350 mm/s (±SD, range, 326-1,349 mm/s) in Group A and 817 ± 307 mm/s (±SD, range, 373-1,185 mm/s) in Group B. In both groups, the implant gradually decelerated because of drag force. With greater distances, the velocity of the DEX implant decreased exponentially to a complete stop at 13.9 mm to 24.7 mm in Group A and at 6.4 mm to 8.0 mm in Group B. Five DEX implants in Group A reached a total distance of more than 15 mm, and their calculated mean velocity at a retinal impact of 15 mm was 408 ± 145 mm/s (±SD, range, 322-667 mm/s), and the consecutive normalized energy was 0.55 ± 0.44 J/m (±SD). In Group B, none of the DEX implants reached a total distance of 6 mm or more. An accidental application at an angle of 30 grade and consecutively reduced distance of approximately 6 mm may result in a mean velocity of 844 and mean normalized energy of 0.15 J/m (SD ± 0.47) in a water-filled eye. The muzzle velocity of DEX implants is approximately 0.8 m/s and decreases exponentially over distance. The drag over time in vitreous is faster than in water. The calculated retinal impact energy does not reach reported damage levels for direct foreign bodies or other projectiles.

Chromium supplementation shortens QTc interval duration in patients with type 2 diabetes mellitus

We investigated the potential effects of chromium supplementation on QTc interval duration in type 2 diabetic patients. Of 60 patients with type 2 diabetes mellitus, 30 were randomly assigned to group A, and 30 to group B. Group A received 1000 microg of chromium picolinate (CrPic) daily for 3 months, followed by placebo in the next 3 months; group B was treated with placebo for the first 3 months and CrPic in the next 3 months. At each visit, QT interval was measured on a standard electrocardiogram by averaging 3 consecutive beats in leads II and V4 and corrected for heart rate with Bazett formula. Although baseline QTc interval was similar in both groups (422 +/- 34 milliseconds in group A vs 425 +/- 24 milliseconds in group B, P = .77), QTc interval at 3 months was shorter in group A (406 +/- 35 milliseconds) than in group B (431 +/- 26 milliseconds, P = .01). In the following 3 months, QTc interval shortened in group B but not in group A, which resulted in a comparable QTc interval duration of both groups at the end of the study (414 +/- 28 milliseconds in group A vs 409 +/- 22 milliseconds in group B, P = .50). Apart from body mass index (31.4 +/- 4.2 kg/m2 in patients with QTc shortening vs 28.7 +/- 4.2 kg/m2 in patients without QTc shortening, P = .03), none of the clinical and laboratory variables predicted QTc interval shortening in our patient cohort. Short-term chromium supplementation shortens QTc interval in patients with type 2 diabetes mellitus.

Transforming growth factor β and diastolic left ventricular dysfunction after heart transplantation: echocardiographic and histologic evidence

Background: The mechanism for chronic left ventricular diastolic dysfunction in the non-rejecting cardiac allograft has not been fully studied. Objectives: The purposes of this study were to analyze the significance and frequency of left ventricular diastolic dysfunction after heart transplantation and to examine the involvement of fibrotic cytokines (transforming growth factor β [TGF-β]) in development of clinical and echocardiographic changes in cardiac allograft recipients. Methods: We studied 152 heart transplant recipients who had survived for at least 24 months. We compared histopathologic findings (staining of endomyocardial biopsy specimens using hematoxylin and eosin, and polyclonal antibodies expressed as TGF-β score), left ventricular function (Doppler echocardiography), and clinical course (New York Heart Association [NYHA] status). We classified patients into Group 1 ( n = 41 recipients) with a restrictive filling pattern, mitral deceleration time (MDT) <140 milliseconds, and Group 2 ( n = 111 recipients), MDT ≥140 milliseconds. Results: The MDT was 122 ± 7 milliseconds in Group 1 compared with an MDT of 177 ± 17 milliseconds in Group 2 ( p = 0.0003). Group 1 showed significant immunohistochemical staining in endomyocardial biopsy specimens (a mean TGF-β score of 9.1 ± 1.2 for Group 1 compared with a mean TGF-β score of 3.6 ± 0.8 for Group 2 p = 0.001). The TGF-β expression correlated inversely with both MDT and isovolumic relaxation time ( r = −0.77, p = 0.0004, and r = −0.69, p = 0.004, respectively). Mean NYHA status in Group 1 recipients was 2.2 ± 1.1 compared with 1.37 ± 0.6 for Group 2 ( p = 0.006). Conclusions: Transforming growth factor β expression in cardiac allografts is associated with impaired left ventricular diastolic function. The pathogenesis of diastolic dysfunction may be an aberrant repair process after rejection-caused TGF-β expression in the allograft.

Auditory input to the human cortex during states of drowsiness and surgical anesthesia

Average responses to clicks and tones were recorded from the primary auditory area (A 1) of man during surgery for the treatment of intracranial diseases. The recording was carried out in two groups, group 1 under local anesthesia and group 2 under general halothane-nitrous oxide anesthesia. Each group consisted of three subjects. In both groups the early component of the evoked activity consisted of a wave having a W shape with two positive deflections P 1 and P 2 interrupted by a small negative N 1. In unanesthetized drowsy men, early average evoked responses from A 1 had a stable and reproducible morphology, and the latency and wave form of these potentials was similar in different subjects. Light general anesthesia produced a prolongation of the latencies of the auditory responses. The mean peak latencies in milliseconds in group 1 were respectively: P 1 = 14.7 ± 1.5; N 1 = 19.1 ± 2.6; P 2 = 32.2 ± 4.1. In group 2 the mean latencies were: P 1 = 20.1 ± 3.4; N 1 = 29.9 ± 8.5; P 2 = 46.1 ± 12.5. The validity of the differences between the two groups was evaluated with the Mann-Whitney U test and found statistically significant. General anesthesia not only affected the latencies of the auditory primary responses but also altered their morphology. The potentials became smaller, and in one case waves P 1 and N 1 were depressed selectively.