Postshock sensing performance in transvenous defibrillation lead systems: analysis of detection and redetection of ventricular fibrillation

INTRODUCTION: The sensing performance of transvenous lead systems may be adversely affected by the delivery of high-energy shocks. This may be due to the proximity of the sensing and energy-delivery electrodes on transvenous leads. METHODS AND RESULTS: The time required for detection of ventricular fibrillation and redetection after a failed first shock was compared in 93 patients with five different lead system-pulse generator combinations: Cadence--Endotak 60 series, Ventak P--Endotak 60 series, Jewel--Transvene, Cadence--TVL, and Cadence--Transvene. A total of 418 successful and 204 failed first shocks were delivered during induced ventricular fibrillation. Redetection times (RED) were consistently shorter than detection times (DET) in the Jewel-Transvene (RED minus DET: -1.9 +/- 0.8 sec, P < 0.0001), the Cadence-TVL (-1.6 +/- 1.0 sec, P < 0.0001), and the Cadence-Transvene combinations (-2.0 +/- 0.9 sec, P < 0.0004). Redetection times were not significantly different than detection times in the Cadence-Endotak combination (0.9 +/- 3.1 sec; P = 0.09). Redetection times were significantly longer than detection times in the Ventak-Endotak combination (1.2 +/- 2.3 sec; P = 0.034). Prolonged individual redetection episodes (> 8.2 sec) were observed in the Cadence-Endotak (7 [10%] of 73 episodes) and the Ventak-Endotak (4 [10%] of 39 episodes), but not in the Jewel-Transvene, the Cadence-TVL, and the Cadence-Transvene combinations. CONCLUSIONS: Redetection of ventricular fibrillation may be delayed in some transvenous lead-pulse generator combinations. Successful redetection of ventricular fibrillation following a failed first shock should be demonstrated prior to hospital discharge of patients with implantable defibrillators.     

导读

案例分析法是了解规划设计的重要途径。其有效之处在于与实际场地的关联性,不足之处则在于概念性的设计案例有诸多的内在不足。案例分析通常并不能表明因果关系,且很难解释信息的变化性。然而,案例分析能够为规划设计的深化推进提供重要的见解。     

FATTY ACIDS AND TOCOPHEROL CONTENTS OF SOME PRUNUS SPP. KERNEL OILS

The oil content as well as the fatty acid and tocopherol composition of kernels from 15 Prunus spp. varieties from Turkey were determined. The oil yields from these kernels varied from 46.3 to 55.5%. The main fatty acids of Prunus spp. kernel oils were oleic acid (43.9–78.5%), linoleic acid (9.7–37%) and palmitic acid (4.9–7.3%). The total amount of vitamin-E-active compounds in the oils varied between 62.9 and 439.9 mg/kg. The predominant tocopherol in most kernel oils was γ-tocopherol. Only two varieties of P. amygdalus and one variety of P. persica showed α-tocopherol as the main vitamin-E-active compound. The composition of the oils was 9–164.5 mg/kg α-tocopherol, 21.5–41.6 mg/kg α-tocotrienol, 1.6–330.2 mg/kg γ-tocopherol and 0–39.1 mg/kg δ-tocopherol. From the results of the present study, it can be concluded that the kernels of the investigated species of Prunus fruits from Turkey may serve potential sources of valuable oil that might be used for edible and other industrial applications.

PRACTICAL APPLICATIONS

The search for new sources of vegetable oils is an ongoing challenge and the further utilization of by-products from the food processing industry is an interesting option in this field. Seed oils from Prunus species contain high amounts of recommended monounsaturated oleic acid moderate contents of linoleic acid and low amounts of saturated fatty acids that may result in more favorable oil than olive oil with regard to their fatty acid compositions. Additionally, the oils contain vitamin-E-active compounds. Both fatty acid composition and vitamin-E-active compounds may justify the further processing of seeds from Prunus species for the production of oil for food and pharmaceutical applications.     

Synthesis and QSAR of some 3-amino-2-(substituted)aminomethyl-5,6-disubstituted thieno[2,3-d]pyrimidin-4(3H)-ones as novel H1-receptor antagonists

The plasma concentrations of two bone matrix proteins (osteocalcin, osteonectin) were monitored in 56 samples from 14 patients receiving renal transplants and the values compared with serum bone alkaline phosphatase mass concentrations and osteotropic hormone levels (parathyroid hormone, calcitriol). There were no significant changes in the concentrations of plasma osteonectin at any time after transplantation, as compared with the values before transplantation (P > 0.1). None of the plasma samples showed osteonectin levels above the reference interval. There was a weak but significant relationship between platelet counts and plasma osteonectin levels (r = +0.322; P < 0.05). Osteocalcin showed a marked decrease of the values 1 week following transplantation as compared with the values before transplantation without further change of the values 1 and 3 months after transplantation (P > 0.5) whereas 3 months after transplantation bone alkaline phosphatase levels were higher than before transplantation (P < 0.05). Multiple regression analysis (performed with data from 42 samples obtained after transplantation) revealed serum creatinine as an independent predictor of plasma osteocalcin whereas serum calcitriol was an independent predictor of serum bone alkaline phosphatase (P < 0.05). No correlation was observed between serum calcitriol/plasma parathyroid hormone on the one hand and plasma osteocalcin on the other (P > 0.05). After transplantation there was a lack of correlation between serum bone alkaline phosphatase mass concentrations and plasma osteocalcin values (P > 0.05). In conclusion, serum bone alkaline phosphatase should be preferred to bone matrix proteins for the assessment of bone metabolism in patients receiving renal transplants: (a) bone alkaline phosphatase-but not osteocalcin-is significantly correlated with calcitriol and adequately reflects increased bone formation after renal transplantation; (b) interpretation of osteocalcin values is severely hampered by their strong correlation with serum creatinine concentrations; (c) plasma osteonectin determinations are not useful for monitoring bone formation.     

Breast cancer screening and related attitudes among Filipino-American women

This study assessed mammography screening rates and related attitudes and intervention preferences in Filipino-American women, a group that has been neglected in cancer control research. Face-to-face interviews were conducted in English and Tagalog with a convenience sample of 218 Filipino women 50 years and older residing in Los Angeles. Sixty-six % had ever had a screening mammogram, 42% had had one in the past 12 months, and 54% in the past 2 years. These rates are about 20% lower than those found among African-American and white women in the 1994 California Behavioral Risk Factor Survey. Women who had received a doctor's recommendation to obtain a mammogram, women stating that they were very likely to obtain a mammogram if a physician recommended it, and women who felt very comfortable requesting a mammogram from a physician were more likely to have been screened. Women who had friends and relatives who had obtained mammograms those stating that their friends and relatives would be very supportive of their getting a mammogram, and those who felt that it was very worthwhile to obtain a mammogram were also more likely to have been screened. The following variables were negatively related to the outcome: concern over cost, the attitude that mammograms are only needed in the presence of symptoms, perceived inconvenience of taking the time and difficulties getting to the mammography facility, and embarrassment. Implications for interventions to increase breast cancer screening are discussed.     

Cardiac arrhythmia caused by a Kirschner wire inside the heart. An unusual complication of finger osteosynthesis

A 45-year-old woman with no previous history of cardiac disease woke up one morning with an irregular heartbeat and fatigue. An electrocardiogram showed atrial fibrillation and plain chest radiographs revealed the presence of a metallic pin at the position of the heart. A 24 mm-long metallic pin was removed by open thoracic surgery from within the right ventricle of the heart. Postoperative examination of the pin showed it to be one of the 0.8 mm Kirschner wires that had been used for finger osteosynthesis in her left hand 31 months previously.     

Postnatal development of low [Mg2+] oscillations in neocortex

One form of rhythmic activity intrinsic to neocortex can be induced in slices of adult somatosensory cortex by lowering [Mg2+]o to unblock N-methyl--aspartate (NMDA) receptors. It has been suggested that a population of intrinsically burst-firing (IB) neurons that are unique to cortical layer 5 may play a role in the rhythmic activity seen under these conditions. Whole cell patch-clamp and field-potential recordings in slices of somatosensory cortex from neonatal rats were used to study the development of IB cells and the development of 0 [Mg2+] oscillations. IB cells were not encountered before postnatal day 12 (P12) in layer 5, but from P13 to P19 an increasing proportion of cells had IB properties. Recordings from cells at P7, P17, and P19 in 0 [Mg2+] indicate that dramatic changes occur postnatally in 0 [Mg2+]-induced activity. At P7, cells largely showed trains of single action potentials. In contrast, at P19, cells showed organized bursts of rhythmic activity lasting 0.5-5 s separated by periods of relative quiescence. Cells recorded at P17 were found to have less organized rhythmic activity than cells from P19 cortex. Field-potential recordings in 0 [Mg2+] made at P7 showed infrequent and slowly occurring field depolarizations, whereas field-potential recordings at P19 consisted of spontaneous bursts of 4-12 Hz oscillations identical to those observed in the adult. Application of NE, which inhibits burst-firing of layer 5 IB cells, significantly altered the discharge pattern of 0 [Mg2+] oscillations at P19. These data suggest that the maturation of one type of rhythmic network activity intrinsic to neocortex is influenced by the development of the membrane properties of a single cell type.