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At least 199 records · Page 11Linked to original sources
PubMed1986

Early and late allergic bronchial reactions: physiological characteristics.

Twenty-four patients with asthma of suspected allergic origin were subjected to a total of twenty-five bronchial provocations with the relevant allergen. Eighteen of them reacted with bronchial obstruction: eleven with an isolated early reaction, five with a dual reaction and two with only a late reaction. Extensive lung function tests were performed. The patterns of early and late reactions were qualitatively very similar regarding variables of pulmonary physiological function, but there were quantitative differences. Patients with dual reactions showed significantly greater changes in FEV1, RV and TGV during the early response than those with isolated early reactions. Maximum mid-expiratory flow rates with the patients breathing air and a mixture of He and O2 were measured before and 6 hr after the challenges. Four of five patients with both an immediate and a late response showed a decrease in the response to helium during the latter phase, suggesting increasing involvement of the small airways. An increase in the slope of the alveolar plateau (phase III) was observed in four of the five patients with dual responses and all five had increased CC%. It was concluded that the changes in pulmonary function occurring during the dual responses were widespread, involving the airways generally and resembling those in the clinically more severe asthma. Usually, individuals with dual reactions showed stronger reactions. In two cases, however, a late reaction was obtained without any preceding early reaction.

Adolescent↗
PubMed1964

SOME PHYSIOLOGICAL CHARACTERISTICS OF NEOMYCIN AND KANAMYCIN-RESISTANT STRAINS OF STAPHYLOCOCCUS AUREUS.

Five hundred and fifty-two strains of Staphylococcus aureus of hospital origin were resistant to penicillin, streptomycin, and tetracycline. Of these, 298 were also resistant to neomycin and kanamycin, and this resistance was related to pigment production on glycerol monoacetate agar, the production of beta-lysin, the absence of fibrinolytic and proteolytic activity, and to phage susceptibility. The use of physiological markers, the inadequacy of phage typing, and the possible reasons for the emergence of neomycin-resistant staphylococci are discussed.

Anti-Bacterial Agents↗
PubMed2001

Tai chi: physiological characteristics and beneficial effects on health.

OBJECTIVES: To assess the characteristic effects of Tai Chi Chuan (TCC) exercise on metabolism and cardiorespiratory response, and to measure its effect on cardiorespiratory function, mental control, immune capacity, and the prevention of falls in elderly people. DESIGN: A review of controlled experimental studies and clinical trials designed with one of two aims: either to assess physiological responses during the performance of TCC or to assess the impact of this exercise on general health and fitness. MAIN OUTCOME MEASURES: Metabolic rate, heart rate, blood pressure, ventilation, maximal oxygen uptake (VO(2)MAX), immune capacity, falls, and fall related factors. SUBJECTS: A total of 2216 men and women. RESULTS: Under review were 31 original studies, published in Chinese or English journals, that met the criteria for inclusion. Most of the papers written in Chinese had not been introduced into the Western literature. Nine of these studies showed that TCC can be classified as moderate exercise, as its does not demand more than 55% of maximal oxygen intake. When this form of exercise and others conducted at equal intensity were compared, TCC showed a significantly lower ventilatory equivalent (VE/VO(2)MAX). Evidence provided by cross sectional and longitudinal studies suggests that TCC exercise has beneficial effects on cardiorespiratory and musculoskeletal function, posture control capacity, and the reduction of falls experienced by the elderly. CONCLUSIONS: TCC is a moderate intensity exercise that is beneficial to cardiorespiratory function, immune capacity, mental control, flexibility, and balance control; it improves muscle strength and reduces the risk of falls in the elderly.

Accidental Falls↗
PubMed1977

Physiological characteristics of a champion runner: age 77.

A world champion distance runner, age 77, was evaluated in various anthropometric, pulmonary, hematological, and cardiorespiratory measures. The subject held 14 recognized world records in track and distance running for competitors aged 74, 75, and 76 years and had 11 records pending for the 77-year-age category. He was the 1975 National AAU Master's class IV-b champion in the 400, 800, 1500, 5000 and 15,000 meter races. The results of the physiological measures taken exceeded those of a more sedentary population of comparable age, were similar to reported values for other Master athletes, and approached the standards noted for much younger runners. The largest age-related decrements were observed in measures of maximal heart rate, maximal pulmonary ventilation, and maximal oxygen consumption. The general reduction in aerobic power was attributed to a combination of pulmonary, circulatory, and metabolic factors in addition to training consideration.

Aged↗
PubMed2002

A telencephalic nucleus essential for song learning contains neurons with physiological characteristics of both striatum and globus pallidus.

The song system of oscine birds has frequently been presented as a model system for motor learning in vertebrates. This practice has been bolstered by the growing recognition that one part of the song system that is essential for song learning, area X, is a component of the avian striatum. The mammalian striatum, the input structure of the basal ganglia, has been implicated in a number of motor-related functions, including motor learning, suggesting that song learning in birds and motor learning in mammals may use similar physiological mechanisms. We studied the intrinsic physiological properties of area X neurons in brain slices to see how closely they match properties identified in mammalian striatal neurons and to collect data that are necessary to understand how area X processes information. We found that area X contains all four physiological cell types present in the mammalian striatum and that each is very similar to its mammalian counterpart. We also found a fifth cell type in area X that has not been reported in mammalian striatum; instead, this cell type resembles neurons that have been recorded in the mammalian globus pallidus. This pallidum-like cell type morphologically resembles the projection neurons of area X. We suggest that area X contains a pathway equivalent to the "direct" striatopallidothalamic pathway through the mammalian basal ganglia, with the striatal and pallidal components intermingled in one nucleus.

4-Aminopyridine↗
PubMed1979

Physiological characteristic and energy balance of Klebsiella aerogenes in a multistage tower fermentor.

Biomass growth, consumption of carbon and energy source, specific rates of formation of metabolic byproducts, biomass yield referred to the C-source and to oxygen, respiration rate and the value of RQ were studied in Klebsiella aerogenes CCM 2318 (on a synthetic glucose medium) at different specific growth rates. Maintenance coefficients and the total energy balance of the cultivation process were evaluated for a multistage tower fermentor with a defined interstage mixing. The results pointed to changes in both glucose metabolism and the physiological state of the population, brought about by changes in specific growth rate. As compared with a chemostat, the culture was found to exhibit a different physiological character is stages 1 and 4 despite a considerable interstage mixing.

Acids↗
PubMed1976

Physiological characteristics of chemostatically grown Citrobacter freundii as a function of the specific growth rate and type of nutrient limitation.

Citrobacter freundii was grown aerobically in a chemostat on a mineral medium with galactose or glucose as carbon and energy sources under limitation by carbon or nitrogen source respectively. At various specific growth rates ranging from 7 to 95% mumax the culture in steady state was analysed and growth yield, specific metabolic rate of substrate utilization, intracellular concentration of pyruvate, ATP, ADP, AMP and energy charge were determined and plotted as functions of dilution rate. In all four types of experiments the physiological state of cells remained practically independent of dilution rate up to D=0.6 mumax, and at a given specific growth rate nearly independent on mumax and type of limitation. At approximately D=0.6 mumax, which is close to the maximum output dilution rate Dm, the physiological state of the cells changed: growth yields decreased and intr cellular pyruvate and adenylates concentrations increased. Consequently, in a given medium two dilution rates exist at which growth rate dx/dt is the same but the physiology of the population is quite different.

Adenosine Diphosphate↗
PubMedDate not supplied

Impact of VEGF expression on the physiological characteristics of clonal cell lines.

BACKGROUND: Vascular endothelial growth factor (VEGF) plays a crucial role in tumor angiogenesis and growth in most solid neoplasia. MATERIALS AND METHODS: Clonal tumor cell lines expressing varying levels of this pro-angiogenic factor were created via recombinant adeno-associated virus infection of a human (HT29) and rodent (SCCVII) tumor model. RESULTS: The alteration in VEGF expression levels did not significantly impact the in vitro growth rate of the clonal cell lines or the expression levels of other known pro-angiogenic factors. However, the tumors that arose from these clonal cell lines did display significant physiological differences. Upregulation of VEGF expression increased the in vivo growth rate and the intratumoral vessel density of the resulting tumors and decreased the extent of tumor necrosis. CONCLUSION: Since the tumor vascular network can impact the efficacy of anti-cancer therapies, these results suggest that VEGF expression may be important to consider in the treatment of cancer.

Angiopoietins↗
PubMed1996

Correlations between ganglioside storage degree and physiological characteristics of neuronal systems--experimental chloroquine intoxication in miniature pig.

Central nervous neuronal patterns of chloroquine-induced ganglioside storage were investigated in miniature pigs. The systematic distribution of this process was first of all characterized by largely identical reproduction of the current storage patterns of native gangliosidosis. Loss of ganglion cells, cytoarchitectonic disintegration and other degenerative changes resulting in the inborn disease were, however, completely avoided by the experimental conditions. This allowed so far unknown clear-cut and much more comprehensive identification of the intensively as well as of gradually less storing neuronal systems. In this way conspicuous correlations between storage degree and physiological quality of certain neuronal systems became apparent. All identified types of the widely dispersed group of inhibitory interneurons were distinguished by particularly extreme residual body storage. These neurons are physiologically exceptional by their permanent activity which is indispensable for normal function of the nervous system. The most instructive counterpart was documented by extreme poor storage manifestations in the large neuronal perikarya of the nucleus mesencephalicus nervi trigemini. These neurons are comparatively very rarely stressed as they mediate the sensation for pain and temperature exclusively. The mentioned and numerous further experimentally ascertained examples substantiated the conclusion that the degree of ganglioside storage in a ganglion cell type in the experimental pig model might essentially be conditioned by frequency and intensity of its neurotransmission activity. The origin of this correlation could be traced back to the participation of ganglioside in the synaptic release of transmitters. The storage process in neuronal systems of the experimental pigs might hence essentially depend on the chloroquine-conditioned impairment in lysosomal degradation of gangliosided which had been involved in the latter process.

Animals↗
PubMed1982

Physiological characteristics of Thiomicrospira sp. Strain L-12 isolated from deep-sea hydrothermal vents.

Growth of the obligately chemolithotrophic Thiomicrospira sp. strain L-12, isolated from a hydrothermal vent at a depth of 2,550 m in the Galapagos Rift region, was optimal at pH 8 and required 200 mM Na+ and divalent ions (Ca2+ and Mg2+). The organism was microaerophilic and tolerated 300 microM sulfide without a decrease in the rate of CO2 incorporation. Growth and CO2 incorporation occurred within the temperature range of 10 to 35 degrees C, with both optimal at 25 degrees C. At the in situ pressure of 250 atm. the rate of CO2 incorporation was reduced by 25% relative to that measured at 1 atm: it was entirely suppressed at 500 atm. The results of this physiological characterization suggest that Thiomicrospira sp. strain L-12 can be an active autotroph in the hydrothermal environment.

Bacterial Physiological Phenomena↗
PubMed1989

[Physiological characteristics and the level of risk factors for ischemic heart disease in marathon runners between 30 and 59 years of age].

The results of anthropometric, biochemical, cardiological and performance capacity studies in the 37 marathon runners, 113 men systematically practising recreational training programme with a domination of endurance exercises and 44 healthy men with little leisure time physical activity have been compared. In comparison with a group of physically non-active persons, the marathon runners are characterized by considerably higher physical working capacity, slimmer figure, lower resting heart rate, lower diastolic blood pressure, high concentration of HDL cholesterol and lower cholesterol: HDL cholesterol index. However, these differences are minimal in comparison with other systematically training persons, and with regard to the majority of factors statistically insignificant. It seems that for reaching the physiological effects desired from the point of view of ischemic heart disease prevention the endurance training of lower capacity and intensity would be sufficient.

Adult↗
PubMed1987

Physiologic characteristics of subjects exhibiting accelerated deterioration of ventilatory function.

From a randomly selected community population sample followed with sequential surveys since 1972, 13 subjects who exhibited a mean annual decline in FEV1 greater than 60 ml/yr were drawn for detailed studies of lung function. These subjects had developed clinically significant airway obstruction during this period of follow-up. Clinical evaluation was not successful in characterizing the nature of the disorder. None of the subjects had alpha-1-antitrypsin deficiency. In a small proportion of subjects, elevated total serum immunoglobulin E may have played a role in the obstructive airway disorder. Some subjects exhibited loss of lung elastic recoil and diminished carbon monoxide diffusing capacity suggestive of developing emphysema. Others appeared to have intrinsic airway disease involving large and/or small airways, which may be fixed in some and responsive to bronchodilator in others. Thus, neither the site nor the nature of the disorder inferred from results of physiologic tests was uniform, illustrating the heterogeneous nature of chronic obstructive lung disease.

Adult↗
PubMedDate not supplied

[The clinico-physiological characteristics of biologically active points].

Biological active acupoints (BAAp) are peculiar markers of the reflector and general vegetative reaction. Their particular structure, relation to neuro-humoral regulation in the organism are still disputable. The experimental study confirms the availability of BAAp morphological subject. The BAAp stimulation causes parasympathomimetic or sympathomimetic reactions in the efferent organs. Changes in the biochemical indicators caused by BAAp stimulation are of a special neurochemical type under definite functional conditions.

Acupuncture Points↗
PubMed1992

[Physiological characteristics of arterial graft for coronary artery bypass surgery].

Arterial grafts have been used widely for coronary artery bypass grafting (CABG) because of their excellent long patency. However, some clinical reports suggest that blood flow in arterial grafts may not be adequate compared with aorto-coronary bypass grafting. Pressure in arterial grafts was measured in patients undergoing CABG. The pressure tracing in the ascending aorta (AA) was maintained during diastole. The systolic pressure wave in ITA and GEA was narrow, while the diastolic pressures fell rapidly: the diastolic pressure in GEA was lower than in ITA. The area under the pressure wave was measured in diastole and in systole. Although there was no significant difference in systolic areas, the diastolic area were lower in ITA than in AA, and lower in GEA than in AA and in ITA. These results clarified that arterial grafts which belong to the systolic-dominant systemic circulation have disadvantages over aorto-coronary bypass grafts, in terms of physiological suitabilities to the diastolic-dominant coronary circulation.

Adult↗
PubMed1993

Commissural neurons of the electrosensory lateral line lobe of Apteronotus leptorhynchus: morphological and physiological characteristics.

Extracellular injections of horseradish peroxidase were used to label commissural cells connecting the electrosensory lateral line lobes of the weakly electric fish Apteronotus leptorhynchus. Multiple commissural pathways exist; a caudal commissure is made up of ovoid cell axons, and polymorphic cells' axons project via a rostral commissure. Intracellular recording and labeling showed that ovoid cells discharge spontaneously at high rates, fire at preferred phases to the electric organ discharge, and respond to increased receptor afferent input with short latency partially adapting excitation. Ovoid cell axons ramify extensively in the rostro-caudal direction but are otherwise restricted to a single ELL subdivision. Polymorphic cells are also spontaneously active, but their firing is unrelated to the electric organ discharge waveform. They respond to increased receptor afferent activity with reduced firing frequency and response latency is long. Electrical stimulation of the commissural axons alters the behavior of pyramidal cells in the contralateral ELL. Basilar pyramidal cells are hyperpolarized and nonbasilar pyramidal cells are depolarized by this type of stimulation. The physiological results indicate that the ovoid cells participate in common mode rejection mechanisms and also suggest that the ELLs may function in a differential mode in which spatially restricted electrosensory stimuli can evoke heightened responses.

Animals↗
PubMedDate not supplied

Physiological characteristics of low-threshold mechanoreceptors in joints, muscle and skin in human subjects.

1. The development of microneurography, in which an insulated tungsten microelectrode is inserted into an accessible peripheral or cranial nerve in awake human subjects, has allowed detailed analyses of the signalling capacities of single mechanoreceptive afferents from the skin, muscles and joints. For example, we know much about how the two classes of rapidly adapting (Meissner and Pacinian) and two classes of slowly adapting (Merkel and Ruffini) cutaneous mechanoreceptors encode forces applied normal or tangential to the skin of the hand and the similarities and differences in glabrous versus non-glabrous skin (and receptors associated with hairs). We also know about stretch- and force-sensitive endings in muscle (the muscle spindle and Golgi tendon organ, respectively) and how they behave during passive or active movements or during isometric contractions. In addition, we have characterized the firing properties of mechanoreceptors in the joint capsules of the fingers. However, we know little about sensory nerves in the periosteum, other than that nociceptors and Pacinian corpuscles exist. 2. In addition to studies on the physiology of sensory endings in human subjects, microstimulation through the recording microelectrode has revealed how the brain deals with the sensory information conveyed by a single afferent. From this work, we know that there is specificity in the sensory channels: electrical stimulation of a single Meissner or Pacinian corpuscle generates frequency dependent illusions of 'flutter' or 'vibration', whereas microstimulation of a single Merkel afferent can produce a percept of 'pressure' and stimulation of a single joint afferent can evoke a sensation of 'joint rotation'. Interestingly, the input from a single Ruffini ending in the skin cannot be perceived and the same is true of muscle spindle afferents. So, where does this leave us with osseoperception from the mouth? Given that the periodontal receptors in the vicinity have been lost, which mechanoreceptive endings could encode forces applied to a bone-implanted prosthesis? 3. Meissner and Merkel endings have very small receptive fields and respond only to local forces. Pacinian corpuscles have an exquisite sensitivity to brisk mechanical events and could respond to such stimuli transmitted through the bone to a remote receptor, but would not be able to encode sustained forces. Ruffini endings also respond to forces applied remote to the receptive field and, unlike the Pacinian corpuscles, respond in a sustained fashion, but would their signals be perceived? Like muscle spindles, it is possible that the coactivation of many Ruffini endings could provide meaningful information. Finally, as we have seen, the input from a single joint receptor can be perceived, but they mostly respond at the limits of joint rotation, so it is unlikely that any associated with the temporomandibular joint could contribute to osseoperception.

Animals↗
PubMed2003

Attentional and physiological characteristics of patients with dental anxiety.

Twenty patients with dental anxiety were investigated while seated in a dental chair in a dental clinic. Heart rate (HR), heart rate variability (HRV), and skin conductance level (SCL) were recorded while the patients were exposed to scenes of dental treatment as well as a Stroop attentional task. Results showed an attentional bias with longer manual reaction times (RT's) to the incongruent compared to the congruent color words as well as the threat compared to the neutral words. Longer RT's to the incongruent and the threat words were found in the low HRV patients compared to the high HRV patients. Furthermore, all patients showed an increase in HR during exposure and the Stroop task compared to baseline. The HRV showed a decrease during the exposure and the Stroop task compared to baseline. HR and HRV did not differ between exposure and the Stroop task. Moreover, HR and HRV did not return to baseline levels during the recovery period. The SCL showed an increase from baseline to exposure, from exposure to the Stroop task and a decrease in the recovery phase. Results showed the importance of vagal cardiac control in attentional, emotional, and physiological processes in patients suffering from dental fear.

Adult↗