PubMed Health⌕ Search

Biomedical subjects

J Z Feng

Publications and source records attributed to J Z Feng.

11 recordsLinked to original sources
PubMed1990

Efficacy of isosorbide-5-mononitrate on painful and silent myocardial ischemia after myocardial infarction.

The anti-ischemic efficacy of isosorbide-5-mononitrate, 20 mg 3 times daily, on silent myocardial ischemia after myocardial infarction was studied in 28 Chinese patients with use of 48 hours of ambulatory electrocardiographic monitoring in a randomized, crossover, single-blind, placebo-controlled study. Isosorbide mononitrate reduced both painful and painless episodes of ischemia compared with placebo. The number of total ischemic episodes was reduced 88%, duration of ischemia 94%, time-ischemia integral 95%, and total maximal ST-segment depression 86% (p less than 0.01). The drug did not alter the heart rate and blood pressure, and had no evident adverse effect. Thus, isosorbide mononitrate is effective and well tolerated in postinfarction patients with silent ischemia.

Adult↗
PubMed1989

[A preliminary report on silent myocardial ischemia detected using ambulatory electrocardiogram monitoring].

572 cases have been examined with ambulatory electrocardiogram monitoring (AEM). They are divided clinically into three groups, (1) cases after myocardial infarction (2) cases with angina (3) cases without coronary artery disease (CAD). The incidences of silent myocardial ischemia (SMI) in the three groups were 80%, 24% and 3% respectively. The ratios of silent myocardial ischemia to symptomatic myocardial ischemia in groups (1) and (2) were 88.8% and 70.4%. It is shown that silent myocardial ischemia is very frequent in CAD. The article also reviewed and discussed the criteria for diagnosis of SMI, the mechanism of its presence, and its relation to degree of ST segment depression and daily activities.

Adult↗
PubMed1989

[24-hour ambulatory blood pressure monitoring in normal and hypertensive subjects].

24-hour ambulatory blood pressures (BP) of 172 normal subjects and 167 hypertensive patients recorded by automatic ambulatory monitoring device (A method) and standard mercury sphygmomanometer (B method) were studied. The results show: (1) 66% of normal subjects and 78% hypertensive patients have an evident circadian rhythm BP during 24-hours, BP readings during sleep and noon time are lower. (2) There is no significant difference between times at work and at home readings (P greater than 0.05), but the mean BP during sleeping time is the lowest (P less than 0.01). (3) The correlative coefficient of 24-hour average BP and casual clinic BP is low (r = 0.38-0.74). (4) The validity and accuracy of ambulatory BP monitoring by A and B methods were compared.

Adult↗
PubMed1985

Postnatal development of the phase-locked response to low frequency tones of auditory nerve fibers in the cat.

The maturation of the auditory nerve's ability to encode temporal information in an acoustic signal was studied in young kittens, 7 to 23 days old, and in adult cats by measuring the degree to which auditory nerve fiber responses are synchronized (phase locked) to low frequency tones. The major findings include the following. In 7- to 10-day-old kittens thresholds are high (around 100 dB), and secure phase locking is observed only at frequencies below about 600 Hz. The upper frequency limit for phase locking in the adult, around 4 kHz, is reached gradually toward the end of the third postnatal week, a time when thresholds also reach their adult levels. The time course of development of the phase-locked response is similar for fibers with different characteristic frequencies (CFs). At all ages studied, the maximal phase synchrony at any given low frequency is generally obtained at stimulus intensities less than 20 dB above the rate threshold and some 10 to 30 dB below the saturation firing level of the fiber. Time delays, estimated from phase-versus-frequency plots, were similar across ages, although they tended to be longer and more variable at lower CFs during the first 2 postnatal weeks. Comparing the phase-locked response of auditory nerve fibers with that of the anteroventral cochlear nucleus neurons from a previous study suggested that the upper frequency limit for phase synchrony was reached later in the nucleus than in the nerve.

Acoustic Stimulation↗
PubMed1983

Geometry and orientation of neuronal processes in cat primary auditory cortex (AI) related to characteristic-frequency maps.

Microelectrode mapping and horseradish peroxidase oxidase histochemistry were combined to study the relationship between the characteristic-frequency representation and the intrinsic connectivity of the primary auditory cortex in the cat. Small extracellular iontophoretic injections of horseradish peroxidase within the characteristic-frequency map resulted in labeling of neuronal processes that, in the tangential plane, radiated out asymmetrically from the injection site over distances of several millimeters. The heaviest concentration of labeled fibers was along an axis parallel with the orientation of the isofrequency line within which the injection had been made. Thus, primary field neurons that have the same or a similar characteristic frequency have the potential of being preferentially interconnected.

Animals↗