Physiological Classification Research Articles

Influence of bread volume on glycaemic response and satiety

The role of carbohydrates in health and disease has received a high profile in recent years, in particular the glycaemic index (GI) as a physiological classification of carbohydrate foods. A common carbohydrate source in the UK is white bread, which is considered to have a high GI value and low satiety value. In the present study, the possibility of favourably altering the GI of white bread by manipulating bread structure (loaf form) was investigated. In a randomised repeated-measures design, ten subjects were tested for glycaemic and satiety responses to four loaves of varying volume, but of consistent macronutrient content. Peak plasma glucose levels and GI values were shown to be significantly reduced by lowering loaf volume (P=0.007, P<0.001 respectively). In addition, a greater satiety index (SI) was seen with decreased loaf volume (P<0.001). In conclusion, the present study demonstrates that reducing the volume of white bread, which is generally considered to be high-GI and low-SI, can favourably alter metabolic and appetite responses. Relatively small differences in the GI of regularly consumed starch foods have been shown to have beneficial effects on health.

Transformation of methylthio-s-triazines via sulfur oxidation by strain JUN7, a Bacillus cereus species

It is known that methylthio-s-triazines can be transformed to the corresponding 2-hydroxy derivatives through sulfoxides and sulfones in aerobic and flooded soil; however, production of sulfoxides and/or sulfones from methylthio-s-triazines by isolated s-triazine-degrading bacteria has not been reported yet. In the present study, a new bacterial strain, JUN7, was obtained from Japanese soil; the bacterium is capable of transforming simetryn to 2-methylsulfinyl 4,6-bis(ethylamino)-s-triazine (sulfoxide simetryn) and 2-hydroxy-4,6-bis(ethylamino)-s-triazine (2-hydroxy simetryn) in a Luria-Bertani (LB) medium. This is the first isolation of the specific microorganism that mediates sulfur oxidation of methylthio-s-triazines, as far as we know. Strain JUN7 could decrease other methylthio-s-triazines such as dimethametryn and prometryn, but not chlorinated s-triazines (atrazine, simazine, and terbuthylazine) and methoxy-s-triazine (atraton) in 1/10 LB medium. Strain JUN7 did not possessed gene atzA or trzN encoding triazine-degrading enzymes, suggesting that the strain may have another metabolic system. Characterizations of strain JUN7 based on comparative morphology, physiological classification, and comparison of the partial 16S rRNA sequence indicated that it is assigned as a Bacillus cereus species.

Surgical approaches to thromboembolism.

Management of angiographically confirmed pulmonary thromboembolism in 313 patients has been based on a physiological classification system. Patients in shock (Class IV) are managed either by catheter embolectomy (26 patients) with 27 per cent mortality rate or by open embolectomy during active resuscitation (6 patients) with a 33 per cent mortality rate. High-risk patients with transient hypotension (Class III) are managed by anticoagulation and filter insertion. The most common indication for filter placement is a contra-indication to anticoagulation (37 per cent). Filter placement was infrarenal in 268 patients (86 per cent) and intentionally suprarenal in 19 patients (6 per cent). Misplacement has occurred into the iliac veins, renal veins and the heart but has not been seen since the guide wire technique for insertion was developed. The 30 day mortality for patients receiving filters was 14 per cent and due to other disorders. Only one death was suspected from recurrent embolism. One hundred and thirteen venacavagrams at intervals up to 99 months in 110 patients showed long-term patency in 97 per cent. Recurrent embolism was seen in five patients (2 per cent) but caused no deaths.

Nitric oxide synthase in human skeletal muscles related to defined fibre types

Skeletal muscle functions regulated by NO are now firmly established. However, the knowledge about the NO synthase (NOS) expression related to a defined fibre type in human skeletal muscles necessitates further clarification. To address this issue, we examined localization of NOS isoforms I, II and III, in human skeletal muscles employing immunocytochemical labeling with tyramide signal amplification complemented with enzyme histochemistry and Western blotting. The NOS immunoreactivity was related to fibre types of different classification systems: physiological classification into slow and fast, ATPase classification into I, IIA, IIAX, IIX, and physiological-metabolic classification into slow-oxidative (SO), fast-oxidative glycolytic (FOG) and fast-glycolytic (FG). We found a correlation of NOS I-III immunoreactivity to metabolic defined fibre types with strong expression in FOG fibres. This implies that NO as modulator of muscle function is involved in oxidative metabolism in connection with fast force development, which only occurs in FOG fibres. The NOS expression showed no correlation to ATPase fibre subtypes due to the metabolic heterogeneity of ATPase fibre types. Healthy and affected vastus medialis muscles after anterior cruciate ligament rupture revealed similar NOS expression level as shown by Western blotting with, however, different expression patterns related to the fibre types in affected muscles. This suggests an altered modulation of force development in the fibres of diseased muscles.

Physiological Classification of Sympathetic Neurons in the Rat Superior Cervical Ganglion

A new scheme is presented for identifying three sympathetic phenotypes in the rat superior cervical ganglion using electrophysiology and neuropeptide Y expression. Postganglionic compound action potentials recorded from the external and internal carotid nerves each contained two peaks, 1 and 2, with distinct preganglionic stimulus thresholds. Peak 2 in the external carotid response contained subpeaks 2a and 2b having a similar stimulus threshold. Neurons corresponding to peaks 1, 2a, and 2b were identified intracellularly by antidromic stimulation, graded preganglionic stimulation, injection with neurobiotin and immunostaining. Seventeen of 53 neurons studied this way had a low threshold for preganglionic stimulation of firing that corresponded to activation of extracellular peak 1. All low-threshold neurons were neuropeptide Y (NPY)-negative. The other 36 neurons had a high presynaptic stimulus threshold that corresponded to activation of extracellular peak 2, and 12 of these cells contained NPY. Together with other known features of ganglionic organization, the results indicate that low-threshold NPY-negative neurons are secretomotor cells projecting to salivary glands, that high-threshold NPY-negative neurons are pilomotor cells responsible for extracellular peak 2a, and that high-threshold, NPY-positive neurons are vasoconstrictor cells responsible for peak 2b. Secreto-, pilo-, and vasomotor neurons identified in this way had distinct axonal conduction velocities (0.52, 0.20, and 0.10 m/s) and diameters (33, 29, and 25 microm) but were indistinguishable in terms of preganglionic conduction velocities (0.30-0.34 m/s) and number of primary dendrites (8.4-8.6). The cell classification scheme presented here will allow future comparison of ganglionic integration in different sympathetic modalities.

Cluster Analysis–Based Physiological Classification and Morphological Properties of Inhibitory Neurons in Layers 2–3 of Monkey Dorsolateral Prefrontal Cortex

In primates, little is known about intrinsic electrophysiological properties of neocortical neurons and their morphological correlates. To classify inhibitory cells (interneurons) in layers 2-3 of monkey dorsolateral prefrontal cortex we used whole cell voltage recordings and intracellular labeling in slice preparation with subsequent morphological reconstructions. Regular spiking pyramidal cells have been also included in the sample. Neurons were successfully segregated into three physiological clusters: regular-, intermediate-, and fast-spiking cells using cluster analysis as a multivariate exploratory technique. When morphological types of neurons were mapped on the physiological clusters, the cluster of regular spiking cells contained all pyramidal cells, whereas the intermediate- and fast-spiking clusters consisted exclusively of interneurons. The cluster of fast-spiking cells contained all of the chandelier cells and the majority of local, medium, and wide arbor (basket) interneurons. The cluster of intermediate spiking cells predominantly consisted of cells with the morphology of neurogliaform or vertically oriented (double-bouquet) interneurons. Thus a quantitative approach enabled us to demonstrate that intrinsic electrophysiological properties of neurons in the monkey prefrontal cortex define distinct cell types, which also display distinct morphologies.

Ecophys.Fish: A Simulation Model of Fish Growth in Time-Varying Environmental Regimes

Ecophys.Fish is a deterministic STELLA® model for simulating rates of fish growth in environmental regimes that have simultaneous temporal variation in food, oxygen, temperature, pH, and salinity. The purpose of this article is to introduce Ecophys.Fish to those who might want to use it as a framework or starting point for applications of their own. We believe our model, although focused in autecology, will prove useful at organizational levels both below and above the individual fish. Ecophys.Fish is a quantitatively explicit interpretation of concepts originally formalized by F.E.J. Fry, almost 60 years ago. Fry's “physiological classification of environment” and his concept of “metabolic scope for activity” were coupled with conventional bioenergetics to provide the model's theoretical basis. The model's inputs are initial size of fish, and time series of temperature, pH, dissolved-oxygen concentration (DO), salinity, and food availability and its energy content. Outputs are food consumption, oxygen consumption, waste production, energy content of fish biomass, and growth. Indirectly, the output is a measure of relative fitness of the fish-environment system to support fish growth. Two variants of the model represent the euryhaline red drum (Sciaenops ocellatus) and the freshwater bluegill (Lepomis macrochirus). Ecophys.Fish had its beginnings in laboratory experiments with juvenile red drum. These experiments enabled definition of functions and their parameterization, leading to a working model that effectively simulated growth of red drum in various pond and estuary trials with caged fish. Subsequently, Ecophys.Fish was converted to simulate growth rates of caged bluegill involved in stream ecoassays. The latter work confirmed the model's generality and the utility of automated routine respirometry for empirically estimating a key model parameter. Ecophys.Fish comprises an effective tool for resolving sources of variation in fish growth, even in natural systems with high levels of environmental variability. Moreover, the model has utility for probing biological and ecological mechanisms underlying fish growth and production. Finally, Ecophys.Fish is capable of producing rich hypotheses, e.g., 1) the optimum temperature for growth decreases whenever DO, food availability, or energy density of available food is limiting; 2) with unlimited DO and food availability, the optimum temperature for growth increases with increasing fish size but only when energy density of food is limiting; and, 3) when neither availability nor energy density of food is limiting, growth can be much faster under diel-cycling regimes of temperature and DO than under the optimum constant temperature/DO regime. Under Ecophys.Fish, environmental regimes that are best for survival are not necessarily those that are best for growth.

The glycaemic index: an overview of its possible role in the prevention and treatment of chronic disease

Summary The concept of a glycaemic index owes much to the dietary fibre hypothesis; that fibre would reduce the rate of nutrient absorption and increase the value of carbohydrate foods in the maintenance of health and treatment of disease. However, several aspects of food other than its fibre content contribute to the glycaemic and endocrine responses postprandially. The aim of the glycaemic index classification of foods was therefore to assist in the physiological classification of carbohydrate foods that, it was hoped, would be of relevance in prevention and treatment of chronic diseases such as diabetes. In the last 20 years, low glycaemic index diets have been reported to improve glycaemic control in patients with diabetes and reduce serum lipids in hyperlipidaemic subjects. Low glycaemic index or glycaemic load diets (glycaemic index multiplied by total carbohydrates) have also been associated with higher levels of high-density lipoprotein cholesterol, reduced C-reactive protein concentrations and, in large cohort studies, with decreased risk of developing diabetes and cardiovascular disease. Some case-control and cohort studies have also found positive associations between dietary glycaemic index and the risk of colon and breast cancer. Although there are inconsistencies in the data, sufficient positive findings have emerged to suggest that the dietary glycaemic index is an aspect of diet with potential importance in the treatment and prevention of chronic diseases.

The infected total knee arthroplasty: Just when you thought it was over

Of the various options available for infected total knee arthroplasties (TKAs), a successful primary-exchange revision technique offers decreased morbidity for the patient by eliminating a second major surgery and associated hospitalization, and substantially reduces the cost associated with this dreaded condition. In 22 infected TKAs treated by a 1-stage revision and followed for an average of 10.2 years (range, 1.4–19.6 years), 90.9% were free of recurrent infection. Knee scores averaged 79.5, with 85.7% good or excellent results. The physiologic classification of the host appeared to influence the outcome of revision. All patients in class A or B (20 knees) had successful eradication of their primary infection after 1-stage revision; 2 physiologic class C patients developed early failure secondary to poor wound healing.

Cardiopulmonary Complications with Non-Anesthesiologist-Administered Propofol vs. Standard Sedation: The CORI Experience

Background: The use of non-anesthesiologist-administered propofol (NAP) has grown in popularity over standard sedation and analgesia (SA) due to its superior recovery profile. Significant cardiopulmonary side effects with propofol have been reported during endoscopy. Previous trials have suggested that NAP is as safe as SA, but definitive conclusions are hampered due to small sample sizes. Purpose: To determine cardiopulmonary complications from NAP and SA utilizing a multicenter endoscopic outcomes database. Methods: GIP and SA cases from 1/16/98-6/30/03 were obtained form CORI for analysis. Clinical variables analyzed included age, gender, ASA physiologic classification, procedure type (EGD, colonoscopy, ERCP), An adjusted relative (ARR) risk was calculated for each clinical variable. Cardiopulmonary complications (CPC)include: chest pain, bradycardia, tachycardia, hypoxia, vasovagal reaction, respiratory distress, hypotension and hypertension) bleeding, perforation, and death. Results: 9,761 NAP and 528,131 SA procedures were analyzed. The overall ARR for NAP when compared to standard sedation was 1.04 (0.876 - 1.24, 95%CI). Older age and higher ASA classification were associated with an increasing risk for complications. (see table) The risk of cardiopulmonary complications for ERCP performed with NAP was 1.28 times that seen for colonoscopy. There was no gender difference. Conclusions: The overall risk of CPC for NAP and SA are equivalent. There appears to be higher CPC risk in NAP patients undergoing ERCP or with advancing age and ASA class. Future prospective studies are needed to validate this risk profile.

Anesthesiologist or Non- Anesthesiologist-Administered Propofol and Cardiopulmonary Complications for Endoscopy: Which Is Safer?

Background: Propofol-mediated endoscopy is gaining popularity due to its enhanced recovery profile when compared to standard sedation. There is no data comparing anesthesiologist (A) or non-anesthesiologist (NA) administered propofol. Purpose: To evaluate cardiopulmonary complications with propofol-mediated sedations utilizing a multicenter endoscopic outcomes database Methods: A and NA cases were gathered from the Clinical Outcomes Research Initiative (CORI) database from 1/16/98-6/30/03. Cardiopulmonary complications (CPC) included: chest pain, bradycardia, tachycardia, hypoxia, vasovagal reaction, respiratory distress, hypotension and hypertension. Clinical variables analyzed included age, gender, ASA physiologic classification, procedure type (EGD, colonoscopy, ERCP), and personnel administering propofol (A vs NA) An adjusted relative risk (NA numerator, A denominator) with 95% CI was calculated for each clinical variable. Results: 9,761 NA and 4,811 A procedures were analyzed. Procedures included colonoscopy: 9,219, EGD:4894, and ERCP 310. Increasing age and gender were not associated with an increased risk of CPC. Advanced ASA classification was associated increased CPE risk. PME under MAC/anesthesiologist was associated with a reduced CPE risk (see table). Conclusion: Advancing ASA is associated with increased CPC risk in non-anesthesiologist-administered propofol procedures, and is present throughout the ASA spectrum The administration of propofol by anesthesiologists is associated with a decreased CPC risk.

Differential diagnosis of anemia

Anemia is often encountered in clinical practice. It has to be noted that anemia is only a symptom of an underlying disease. Early, correct and consequent diagnosis is crucial in order to prevent late detection of fatal disease or to prescribe contraindicated therapy. The combined use of a morphologic and physiologic classification allows for understanding and correct classification of anemia in a specific patient. In this respect, the determination of reticulocyte counts is of special importance. Further targeted biochemical, morphological and immunological analysis leads to the definitive diagnosis of anemia. A large proportion of the anemias can be diagnosed and treated by the general practitioner. However, involvement of a haematologist is recommended in several clinical situations, such as newly diagnosed haemolytic anemia, as well as in patients with complex, equivocal or therapy-refractory anemia or certain normocytic hyporegenerative anemias. This paper presents a differentiated stepwise approach in diagnosing anemic disorders.

Myoclonus.

Myoclonus refers to brief muscle jerks caused by neuronal discharges. Etiologies are numerous, ranging from physiological jerks to myoclonus secondary to severe neurodegenerative conditions. The source of myoclonus may be in the cerebral cortex, the brain stem or the spinal cord and multiple generators may be involved in a single patient. The clinical approach to myoclonus relies on both etiological and physiological classifications. Pharmacological therapy is largely based on the presumed site of origin of myoclonus. Polytherapy may be required, particularly in severe cases of cortical myoclonus.

Glycemic index: overview of implications in health and disease , , ,

The glycemic index concept is an extension of the fiber hypothesis, suggesting that fiber consumption reduces the rate of nutrient influx from the gut. The glycemic index has particular relevance to those chronic Western diseases associated with central obesity and insulin resistance. Early studies showed that starchy carbohydrate foods have very different effects on postprandial blood glucose and insulin responses in healthy and diabetic subjects, depending on the rate of digestion. A range of factors associated with food consumption was later shown to alter the rate of glucose absorption and subsequent glycemia and insulinemia. At this stage, systematic documentation of the differences that exist among carbohydrate foods was considered essential. The resulting glycemic index classification of foods provided a numeric physiologic classification of relevant carbohydrate foods in the prevention and treatment of diseases such as diabetes. Since then, low-glycemic-index diets have been shown to lower urinary C-peptide excretion in healthy subjects, improve glycemic control in diabetic subjects, and reduce serum lipids in hyperlipidemic subjects. Furthermore, consumption of low-glycemicindex diets has been associated with higher HDL-cholesterol concentrations and, in large cohort studies, with decreased risk of developing diabetes and cardiovascular disease. Case-control studies have also shown positive associations between dietary glycemic index and the risk of colon and breast cancers. Despite inconsistencies in the data, sufficient, positive findings have emerged to suggest that the dietary glycemic index is of potential importance in the treatment and prevention of chronic diseases.

Physiological classification of anovulatory conditions in cattle

Evaluation of follicular growth patterns by ultrasound combined with measurement of circulating reproductive hormones has allowed designation of three functionally critical follicular sizes during the final stages of follicular growth: emergence (∼4 mm), deviation (∼9 mm), and ovulation (variable from 10 to 20 mm). Classification of anovulatory conditions on the basis of these three critical points is logical and provides for rational diagnosis and treatment of the underlying physiological condition. In extreme undernutrition, there is growth of follicles to emergence but not to deviation; however, the underlying pathophysiology is not defined because of relatively few scientific investigations of this condition. Anovulatory conditions with growth of follicles to deviation but not to ovulatory size have been extensively studied. Undernutrition and/or suckling can cause this anovulatory condition. It is characterized by a greater negative feedback effect of estradiol on GnRH/LH pulses than found in normally cycling cows. Another anovulatory condition that is common in high producing lactating dairy cows is characterized by growth of follicles to larger than ovulatory size, such as is observed in cows with follicular cysts. This condition is characterized by an insensitivity of the hypothalamus to the positive feedback effects of estradiol. Thus, these last two common anovulatory conditions appear to be primarily due to changes in the responsiveness of the hypothalamus to estradiol. Treatments that increase circulating progesterone concentrations can help in the treatment of these two conditions by potentially altering GnRH/LH pulses and allowing the final stages of follicular growth or resetting the hypothalamic responsiveness to the positive feedback effects of estradiol.

Systematic Transesophageal Echocardiographic Examination in Mitral Valve Repair

Systematic Transesophageal Echocardiographic Examination in Mitral Valve Repair

A Geometric Model for Physiologic State Classification and Severity Classification of Critically Ill Patients

Abstract A model that represents physiologic states of patients as vectors in a 3-dimensional Euclidean space is presented. The model has been developed from observational data that were obtained from 3250 sets of 17 quantitative physiologic measurements from 919 patients at three centers. Concepts and tools of cluster analysis along with related methods of multivariate data analysis were used to define a reference state and six prototype physiologic patterns of adaptation, viewed as departures from the reference state, of the host defense response to events such as injury and sepsis. Within the model, the vectors from the origin (reference state) to each of the prototype states define directions that are indicative of the physiologic patterns associated with that state. These patterns provide a basis for a useful clinical interpretation for the nature and severity of a patient's response as function of location in the 3-dimensional space. The collaborative process used for the development of this model is described. This process had to blend prior clinical knowledge with statistical tools and concepts to provide a rational basis for defining objectives for the classification problem. Key elements in this process are discussed and related to current issues in the application of classification theory and cluster analysis methods. The effective use of this model to organize the multifactor data necessary to cope with complex clinical decisions that are omnipresent in the care and treatment of patients with post-trauma critical illness is discussed. Herman Friedman will describe the model and discuss key elements of the collaborative process and Dr. Siegel will delineate the physiologic basis of the model and its clinical applications to critically ill and injured patients.

Ambient oxygen tension, metabolic rate, and habitat selection in freshwater snails

The relationship between ambient oxygen tension (PO 2 ) and metabolic rate (VO 2 ) in freshwater snails was examined in order to determine if habitat selection is influenced by hypoxia tolerance. Laboratory and field data were collected on 11 species from lotic and lentic habitats. Metabolic rates were determined at 15 and 25 °C using a closed respirometer technique. In 3 of 20 cases, species were judged to be metabolic O 2 conformers, in 8 of 20 to be metabolic O 2 regulators, and in 9 of 20 to have two zones of metabolic O 2 conformation, with the zone in the higher range of PO 2 being characterized by less fall in VO 2 with declining PO 2 than in the zone in the lower range of PO 2 . We conclude that the response of aquatic VO 2 to hypoxia among snails can not be predicted by any single taxonomic, ecological, or physiological classification.

PLASMA NITRIC OXIDE IN POSTTRAUMA CRITICAL ILLNESS

The time course of nitric oxide (NO) production in posttrauma critical illness was monitored, and its relationship to posttrauma "sepsis/SIRS" and physiologic patterns was described. Eighty multiple trauma patients were studied (514 samples) during their course in the intensive care unit (Injury Severity Score 27.6; 36% deaths). Plasma NO was estimated from NO3 + NO2 by the Griess test and compared with that of 10 healthy controls (HC). At each sample period, the patient was categorized as having bacteremic sepsis (BAC), sepsis syndrome (SS), or systemic inflammatory response syndrome (SIRS), and classified by Physiologic State Severity Classification (PSSC) into normal stress response (A-State), metabolic insufficiency (B-State), or respiratory insufficiency (C2-State), each quantified by their physiologic "distance" from reference state of recovering trauma patients (R-State). A severity index (L2PDEATH), based on a logistic model of state distances from R-State, quantified probability of death. Deaths showed increased NO (p < .05) over survivors or HC by day 3 posttrauma. A fall in vascular tone in deaths was related to the increased NO (p < .0001). The level of NO was higher as sepsis worsened: BAC > SS > SIRS > HC (all simultaneous, p < .05). PSSC and L2PDEATH correlated with incidence > HC and level of NO. In conclusion, the severity of posttrauma critical illness was classified by PSSC and quantified by the L2PDEATH index. These reflect progressively increased NO levels and suggest worsening sepsis status. The reduced total peripheral resistance (TPR)-to-flow relationship (vascular tone) in deaths characteristic of the more severe septic PSSC states appeared related to the increased plasma NO.

"Sepsis/SIRS," physiologic classification, severity stratification, relation to cytokine elaboration and outcome prediction in posttrauma critical illness.

To develop a quantitative severity stratification within the framework of a Physiologic State Classification (PSSC) system that can be applied to critically ill post-trauma patients with "sepsis/SIRS" and to relate PSSC to the nature of the plasma cytokine response. At each study time period, a patient was classified into one of seven physiologic States previously derived from clustering 17 cardiopulmonary and metabolic variables from 338 critically ill patients: R = reference, A = normal stress response, B = metabolic insufficiency, C1 (early) and C2 (late) = respiratory insufficiency, D = cardiogenic insufficiency, H = nonshock hypovolemia. The PSSC used State data from a developmental set of 159 trauma patients in a logistic model (L2PDEATH) to provide a quantitative index of severity. This severity index was tested on 80 new trauma patients (mean injury Severity Score (ISS) = 27.6, 64% survivors). Using PSSC State distributions for evaluation of enzyme-linked immunosorbent assay (ELISA) measured cytokines interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor (TNF) showed the multicytokine score to be greatest in those C2- and B-State regions associated with a higher severity as measured by L2PDEATH. Compared with ARDEATH of the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system, L2PDEATH provided a better indicator of severity of sepsis/systemic inflammatory response syndrome (SIRS) for posttrauma patients. PSSC allows classification of the physiologic and cytokine mediator response to trauma and permits stratification of severity in posttrauma critical illness.