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Based on animal models, we specify the major role of different bioactive milk components known to participate significantly in neonatal health promotion and in protection against a large number of infectious diseases and the development of allergies and asthma. [ABSTRACT FROM AUTHOR]

There is increasing evidence of the local effects within the gastro intestinal tract and the systemic functions of human milk oligosaccharides (HMO). In addition to the vast majority of in vitro data, animal studies underline the high potential of HMO to influence very different processes. HMO probably influence the composition of the gut microflora through effects on the growth of bifidus bacteria.Whether the concomitant low number of pathogenic microorganisms in breastfed infants is also caused by HMO is an intriguing question that still has yet to be proven. Due to the similarity of HMO to epithelial cell surface carbohydrates, an inhibitory effect on the adhesion of pathogens to the cell surface is most likely. If this could be shown in humans, HMO would provide a new way to prevent or treat certain infections. It would also indicate supplementing infant formula based on cow's milk with HMO, as those oligosaccharides are either not detectable or present only in low numbers in bovine milk. As some HMO can be absorbed and circulate in blood, systemic effects may also be influenced. Due to their similarities to selectin ligands, HMO have been tested in in vitro studies demonstrating their anti-inflammatory abilities. For example, it has been shown that sialic acid-containing oligosaccharides reduce the adhesion of leukocytes to endothelial cells, an indication for an immune regulatory effect of certain HMO. We cover these topics after a short introduction on the structures of HMO, with a particular emphasis on their blood group and secretor specificity. [ABSTRACT FROM AUTHOR]

Probiotics are defined as live microorganisms that, when administered in adequate amount, confer a health benefit on the host. Amongst the many benefits associated with the consumption of probiotics, modulation of the immune system has received the most attention. Several animal and human studies have provided unequivocal evidence that specific strains of probiotics are able to stimulate as well as regulate several aspects of natural and acquired immune responses. There is also evidence that intake of probiotics is effective in the prevention and/or management of acute gastroenteritis and rotavirus diarrhoea, antibiotic-associated diarrhoea and intestinal inflammatory disorders such as Crohn's disease and pouchitis, and paediatric atopic disorders. The efficacy of probiotics against bacterial infections and immunological disorders such as adult asthma, cancers, diabetes, and arthritis in humans remains to be proven. Also, major gaps exist in our knowledge about the mechanisms by which probiotics modulate immune function. Optimum dose, frequency and duration of treatment required for different conditions in different population groups also remains to be determined. Different probiotic strains vary in their ability to modulate the immune system and therefore efficacy of each strain needs to be carefully demonstrated through rigorously designed (randomised, doubleblind, placebo-controlled) studies. This chapter provides an over view of the immunomodulatory effects of probiotics in health and disease, and discusses possible mechanisms through which probiotics mediate their disparate effects. [ABSTRACT FROM AUTHOR]

The role of colostrum and milk in the neonate has been chiefly recognized as a comprehensive nutrient foodstuff. In addition, the provision of colostrum —the first milk —for early immune capacity has been well documented for several species. Colostrum is additionally a rich and concentrated source of various factors that demonstrate biological activity in vitro. Three hypotheses have been proposed for the phenotypic function of these secreted bioactive components: (1) only mammary disposal, (2) mammary cell regulation, and (3) neonatal function [gastrointestinal tract (GIT) or systemic]. Traditionally, it was assumed that the development of the GIT is preprogrammed and not influenced by events occurring in the intestinal lumen. However, a large volume of research has demonstrated that colostrum (or milk-borne) bioactive components can basically contribute to the regulation of GIT growth and differentiation, while their role in postnatal development at physiological concentrations has remained elusive. Much of our current understanding is derived from cell culture and laboratory animals, but experimentation with agriculturally important species is taking place. This chapter provides an overview of work conducted primarily in neonatal calves and secondarily in other species on the effects on neonates of selected peptide endocrine factors (hormones, growth factors, in part cytokines) in colostrum. The primary focus will be on insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) and other bioactive peptides, but new interest and concern about steroids (especially estrogens) in milk are considered as well. [ABSTRACT FROM AUTHOR]

Recombinant human proteins produced by the mammary glands of genetically modified transgenic livestock mammals represent a special aspect of milk bioactive components. For therapeutic applications, the often complex posttranslational modifications of human proteins should be recapitulated in the recombinant products. Compared to alternative production methods, mammary gland production is a viable option, underlined by a number of transgenic livestock animal models producing abundant biologically active foreign proteins in their milk. Recombinant proteins isolated from milk have reached different phases of clinical trials, with the first marketing approval for human therapeutic applications from the EMEA achieved in 2006. [ABSTRACT FROM AUTHOR]

Peptides play an important primary role as a supply of essential amino acids and a source of nitrogen. Recent studies have reported on another role of peptides: having specific amino acid sequences that can express some biological functions in vivo. For an exhaustive study and supply of biologically active peptides, a large-scale screening of protein sources is necessary. Various physiologically functional peptides, such as opioid, immunostimulating, mineral carrier, ACE inhibitory, antihypertensive, and antimicrobial peptides, have been derived from milk protein: both caseins and whey proteins (Meisel, 1998; Korhonen&Pihlanto-Lepp älä , 2001). Milk is known to be a rich source for the supply of bioactive peptides compared to other protein sources such as animal and fish meat, wheat, and soybean proteins. Among the bioactive peptides, ACE inhibitory peptides and antihypertensive peptides have been extensively researched worldwide, because hypertension is a major risk factor in cardiovascular disease, such as heart disease (FitzGerald&Meisel, 2000; Kitts&Weiler, 2003). We discuss the isolation, utilization, and application of bioactive peptides, especially ACE inhibitory peptides and antihypertensive peptides including our recent human studies on their use as a functional food material. [ABSTRACT FROM AUTHOR]

There is no doubt that milk proteins provide excellent nutrition for the suckling. However, apart from that, milk proteins can also exert numerous physiological activities benefiting the suckling in a variety ofways. These activities include enhancement of immune function, defense against pathogenic bacteria, viruses, and yeasts, and development of the gut and its functions. Besides the naturally occurring, biologically active proteins present in milk, a variety of bioactive peptides are encrypted within the sequence of milk proteins that are released upon suitable hydrolysis of the precursor protein. A large range of bioactivities has been reported for milk protein components, with some showing more than one kind of biological activity (Korhonen&Pihlanto, 2006). This chapter reviews the most important antimicrobial and antitumor peptides derived from milk proteins, especially those that may have a physiological significance to the suckling neonate. Antimicrobial peptides present in milk that are not derived frommilk proteins are also considered. Special attention is given to the generation of these peptides by the action of different proteolytic enzymes and the origin of these enzymes since, if present in the digestive tract, it is likely that the peptides might play a role in the host defense system. Finally, the most relevant in vivo studies carried out with this kind of bioactive peptides are discussed. [ABSTRACT FROM AUTHOR]

Bioactive peptides encrypted within the native milk proteins can be released by enzymatic proteolysis, food processing, or gastrointestinal digestion. These peptides possess a wide range of properties, including immunomodulatory properties. The first months of life represent a critical period for the maturation of the immune system because a tolerance for nutrient molecules should be developed while that for pathogen-derived antigens is avoided. Evidence has accumulated to suggest that milk peptides may regulate gastrointestinal immunity, guiding the local immune system until it develops its full functionality. Our data using the weaning piglet as the model suggest that several milk peptides can downregulate various immune properties at a time (one to two weeks after weaning) that coincides with immaturity of the immune system. The protein kinase A system and/or the exchange protein directly activated by cyclic AMP (Epac-1) are implicated in the mechanism through which milk peptides can affect immune function in the early postweaning period. Despite the fact that the research in this field is in its infancy, the evidence available suggests that milk protein peptides may promote development of neonatal immune competence. Milk contains a variety of components that provide immunological protection and facilitate the development of neonatal immune competence. Two main categories of milk compounds are thought to be associated with immunological activity. The first category includes cytokines, which neonates do not produce efficiently. Cytokines present in milk are thought to be protected against intestinal proteolysis and could alleviate immunological deficits, aiding immune system maturation (Kelleher&Lonnerdal, 2001; Bryan et al., 2006). The second category of milk compounds includes milk protein peptides. Milk peptides may affect mucosal immunity possibly by guiding local immunity until it develops its full functionality (Baldi et al., 2005). This chapter focuses on the effects of milk peptides on immune function and attempts to provide an overview of the knowledge available in this field. [ABSTRACT FROM AUTHOR]

A proline-rich polypeptide (PRP), later called colostrinin (CLN), was originally found as a fraction accompanying sheep colostral immunoglobulins. Extensive in vitro and in vivo studies in mice revealed its interesting T cell-tropic activities. The polypeptide promoted T cell maturation from early thymic precursors that acquired the phenotype and function of mature, helper cells; on the other hand, it also affected the phenotype and function of mature T cells. In particular, PRP was shown to recruit suppressor T cells in a model of T cell-independent humoral immune response and suppressed autoimmune hemolytic anemia in New Zealand Black mice. Subsequent in vitro studies in the human model revealed that CLN regulated mitogen-induced cytokine production in whole blood cultures. A discovery that CLN promoted procognitive functions in experimental animal models, supported by other laboratory findings, indicating prevention of pathological processes in the central nervous system, led to application of CLN in multicenter clinical trials. The trials demonstrated the therapeutic benefit of CLN in Alzheimer's disease (AD) patients by delaying progress of the disease. [ABSTRACT FROM AUTHOR]

HAMLET (human a-lactalbumin made lethal to tumor cells) is a molecular complex derived from human milk that kills tumor cells by a process resembling programmed cell death. The complex consists of partially unfolded a-lactalbumin and oleic acid, and both the protein and the fatty acid are required for cell death. HAMLET has broad antitumor activity in vitro, and its therapeutic effect has been confirmed in vivo in a human glioblastoma rat xenograft model, in patients with skin papillomas and in patients with bladder cancer. The mechanisms of tumor cell death remain unclear, however. Immediately after the encounter with tumor cells, HAMLET invades the cells and causes mitochondrial membrane depolarization, cytochrome c release, phosphatidyl serine exposure, and a low caspase response. A fraction of the cells undergoes morphological changes characteristic of apoptosis, but caspase inhibition does not rescue the cells and Bcl-2 overexpression or altered p53 status does not influence the sensitivity of tumor cells toHAMLET. HAMLET also creates a state of unfolded protein overload and activates 20S proteasomes, which contributes to cell death. In parallel, HAMLET translocates to tumor cell nuclei, where high-affinity interactions with histones cause chromatin disruption, loss of transcription, and nuclear condensation. The dying cells also show morphological changes compatible with macroautophagy, and recent studies indicate that macroautophagy is involved in the cell death response to HAMLET. The results suggest that HAMLET, like a hydra with many heads, may interact with several crucial cellular organelles, thereby activating several forms of cell death, in parallel. This complexity might underlie the rapid death response of tumor cells and the broad antitumor activity of HAMLET. [ABSTRACT FROM AUTHOR]

An innate immune system capable of distinguishing among self, non-self, and danger is a prerequisite for health. Upon antigenic challenge, pattern recognition receptors (PRRs), such as the Toll-like receptor (TLR) family of proteins, enable this system to recognize and interact with a number of microbial components and endogenous host proteins. In the healthy host, such interactions culminate in tolerance to self-antigen, dietary antigen, and commensal microorganisms but in protection against pathogenic attack. This duality implies tightly regulated control mechanisms that are not expected of the inexperienced neonatal immune system. Indeed, the increased susceptibility of newborn infants to infection and to certain allergens suggests that the capacity to handle certain antigenic challenges is not inherent. The observation that breast-fed infants experience a lower incidence of infections, inflammation, and allergies than formula-fed infants suggests that exogenous factors in milk may play a regulatory role. There is increasing evidence to suggest that upon exposure to antigen, breast milk educates the neonatal immune system in the decision-making processes underlying the immune response to microbes. Breast milk contains a multitude of factors such as immunoglobulins, glycoproteins, glycolipids, and antimicrobial peptides that, qualitatively or quantitatively, may modulate how neonatal cells perceive and respond to microbial components. The specific role of several of these factors is highlighted in other chapters in this book. However, an emerging concept is that breast milk influences the neonatal immune system's perception of "danger." Here we discuss how CD14, a soluble PRR in milk, may contribute to this education. [ABSTRACT FROM AUTHOR]

Lactoferrin (Lf) is an iron binding glycoprotein of the transferrin family that is expressed in most biological fluids and is a major component of mammals' innate immune system. Its protective effect ranges from direct antimicrobial activities against a large panel of microorganisms, including bacteria, viruses, fungi, and parasites, to anti-inflammatory and anticancer activities. This plethora of activities is made possible by mechanisms of action implementing not only the capacity of Lf to bind iron but also interactions of Lf with molecular and cellular components of both host and pathogens. This chapter summarizes our current understanding of the Lf structure-function relationships that explain the roles of Lf in host defense. [ABSTRACT FROM AUTHOR]

There are two main sources of lipoprotein membranes in milk: the relatively well-defined milk fat globule membrane (MFGM) that covers the milk fat globules, and the much less attended lipoprotein source, in the form of vesicles floating in the milk serum. We challenge the common view that the milk serum lipoprotein membrane (MSLM) is secondly derived from the MFGM and present a different view suggesting that it represents Golgi-derived vesicles that are released intact to milk. The potential role of enzymes attached to the MSLMand MFGM is considered in detail for select ubiquitously expressed enzymes. [ABSTRACT FROM AUTHOR]

The milk fat globule membrane (MFGM) is the membrane surrounding lipid droplets during their secretion in the alveolar lumen of the lactating mammary gland. MFGM proteins represent only 1-4% of total milk protein content; nevertheless, the MFGM consists of a complex system of integral and peripheral proteins, enzymes, and lipids. Despite their low classical nutritional value, MFGMproteins have been reported to play an important role in various cellular processes and defense mechanisms in the newborn. Using a proteomic approach, such as high-resolution, two-dimensional electrophoresis followed by direct protein identification by mass spectrometry, it has been possible to comprehensively characterize the subcellular organization of MFGM. This chapter covers the description of MFGM proteomics from the first studies about 10 years ago through the most recent papers. Most of the investigations deal with MFGMs from human and cow milk. [ABSTRACT FROM AUTHOR]

Milk has long been recognized as a source of macro- and micronutrients, immunological components, and biologically active substances, which not only allow growth but also promote health in mammalian newborns. Many milk lipids, lipid-soluble substances, and their digested products are bioactive, including vitamins and vitamin-like substances. Vitamins A, E, D, and K and carotenoids are known as highly lipophilic food microconstituents (HLFMs), and all occur in milk. HLFMs also include phytosterols, which, although they are not vitamins, are nevertheless biologically active and present in milk. Fat-soluble micronutrients, including fat-soluble vitamins, are embedded in the milk fat fraction, and this has important implications for their bioaccessibility and bioavailability from milk. In fact, the fat component of milk is an effective delivery system for highly lipophilic microconstituents. The vitamin content of animal products can be enhanced by increasing the feed content of synthetic or natural vitamins or precursors. An advantage of augmenting milk microconstituents by animal nutrition rather than milk fortification is that it helps safeguard animal health, which is a primary factor in determining the quality, safety, and wholesomeness of animal-origin foods for human consumption. The milk fat delivery system offers numerous possibilities for exploitation by nutritionists. For example, the payload could consist of enhanced levels of several micronutrients, opening possibilities for synergic effects that are as yet incompletely understood. [ABSTRACT FROM AUTHOR]

The effect of nutrition on milk fat yield and composition has largely been investigated in cows and goats, with some differences for fatty acid (FA) composition responses and marked species differences in milk fat yield response. Recently, the characterization of lipogenic genes in ruminant species allowed in vivo studies focused on the effect of nutrition on mammary expression of these genes, in cows (mainly fed milk fat-depressing diets) and goats (fed lipid-supplemented diets). These few studies demonstrated some similarities in the regulation of gene expression between the two species, although the responses were not always in agreement with milkFAsecretion responses.Acentral role for trans-10 C18:1 and trans-10, cis-12 CLA as regulators of milk fat synthesis has been proposed. However, trans-10 C18:1 does not directly control milk fat synthesis in cows, despite the fact that it largely responds to dietary factors, with its concentration being negatively correlated with milk fat yield response in cows and, to a lesser extent, in goats. Milk trans-10, cis-12CLAis often correlated with milk fat depression in cows but not in goats and, when postruminally infused, acts as an inhibitor of the expression of key lipogenic genes in cows. Recent evidence has also proven the inhibitory effect of the trans-9, cis-11 CLA isomer. The molecular mechanisms by which nutrients regulate lipogenic gene expression have yet to be well identified, but a central role for SREBP-1 has been outlined as mediator of FA effects, whereas the roles of PPARs and STAT5 need to be determined. It is expected that the development of in vitro functional systems for lipid synthesis and secretion will allow future progress toward (1) the identification of the inhibitors and activators of fat synthesis, (2) the knowledge of cellular mechanisms, and (3) the understanding of differences between ruminant species. [ABSTRACT FROM AUTHOR]

The biological and physiological effects of exogenous FGF1 and VEGF were measured using the KHT murine fibrosarcoma tumor model. Tumor-bearing C3H mice were treated intratumorally with either one or six daily doses of 6 μ g/mouse FGF1, VEGF, or saline. Tumors were excised 24 hrs after the final injection. Compared to controls, only FGF1 treatment significantly increased tumor weight and size, and only in the 6 dose group. Both FGF1 and VEGF administration (6 dose) decreased tumor cell hypoxia as detected by EF5 uptake: 85% ± 5% for FGF1 and 82% ± 6% for VEGF versus 100% ± 6% for controls. Decreased tumor cell EF5 staining, however, was not associated with changes in numbers of structural or angiogenic vessels. DiOC7 staining showed a slight decrease in perfused vessel numbers in tumors treated with daily VEGF. Intratumoral injections of FGF1 or VEGF also slightly decreased the tumor tissue chemokine MCP-1, interleukins (IL-1β , IL-6, and IL-18) mRNA expression, and increased NFκ B binding without altering Ap-1 binding of Iκ B protein expression. In summary, single pulse exposures of tumors to angiogenic factors had little or no effects on tumor growth or perfusion, while daily exposures stimulated tumor growth through improved tumor oxygenation. This improved vascular function occurs without an increase in vascular density. [ABSTRACT FROM AUTHOR]

We investigated whether tissue hypoxia in sepsis produces substantial modifications of convective airway washout and consequently of CO 2 transit time. Single breath tracing for carbon dioxide (SBT-CO 2) was analysed in 18 ICU septic patients. Nine patients had tissue hypoxia events. Using the Hill formula, all tracings were analysed point by point to obtain the time required for CO 2 to achieve 50% maximal value and the Fractional Expiratory Time 50 (FET 0.5) . Hypoxic patients FET 0.5 and CO 2 clearance were compared with non-hypoxic patients data. In hypoxic group CvCO 2 , CO 2 clearance and FET 0.5 values were higher than in non hypoxic group. During the recovery from hypoxia capnographic parameters did not differ from those recorded in the hypoxic period. CO 2 clearance, but not FET 0.5 , correlated with arterial lactate and base excess either in hypoxic or in recovery period. In conclusion in septic patients tissue hypoxia influences CO 2 elimination, modifying SB-CO 2 tracing and lengthening FET 0.5 . [ABSTRACT FROM AUTHOR]

Transient global brain ischemia induced by cardiac arrest and resuscitation (CAR) results in reperfusion injury associated with oxidative stress. Oxidative stress is known to produce delayed selective neuronal cell loss and impairment of brainstem function, leading to post-resuscitation mortality. Levels of 4-hydroxy-2-nonenal (HNE) modified protein adducts, a marker of oxidative stress, was found to be elevated after CAR in rat brain. In this study we investigated the effects of an antioxidant, alpha-phenyl-tert-butyl-nitrone (PBN) on the recovery following CAR in the aged rat brain. Male Fischer 344 rats (6, 12 and 24-month old) underwent 7-minute cardiac arrest before resuscitation. Brainstem function was assessed by hypoxic ventilatory response (HVR) and HNE-adducts were measured by western blot analysis. Our data showed that in the 24-month old rats, overall survival rate, hippocampal CA1 neuronal counts and HVR were significantly reduced compared to the younger rats. With PBN treatment, the recovery was improved in the aged rat brain, which was consistent with reduced HNE adducts in brain following CAR. Our data suggest that aged rats are more vulnerable to oxidative stress insult and treatment with PBN improves the outcome following reperfusion injury. The mechanism of action is most likely through the scavenging of reactive oxygen species resulting in reduced lipid peroxidation. [ABSTRACT FROM AUTHOR]

The ratio of oxygenated to total haemoglobin (Hb), or rSO2, obtained by near infra-red spectroscopy (NIRS), includes both arterial and venous blood of the region examined. The relationship of arterial oxygen extraction, E, and saturation, SaO2, to rSO2 can be expressed, for normally functioning tissue, as E = 1.39(1 - rSO2/SaO2). Cerebral E, at rest, is constant at lower altitudes but is reduced at 5000 m. This corresponds to constant values of E for SaO2 values above 90% (approximately). E declines linearly for lower SaO2 values, either including measurement at high altitude or at sea level with a reduced inspiratory oxygen concentration. In addition to measurements of brain NIRS resting oxygen extraction of liver, muscle and kidney have also been calculated from NIRS measurements made, on normal inspired air, at sea level and after acute ascent to 2400 m and 5050 m. At 5050 m E was reduced for all four regions but at 2400 m was the same as at sea level for brain, liver and muscle; for the kidney E was elevated at 2400 m. Cerebral oxygen extraction was calculated for rest and the full range of exercise. It was constant at sea level for the lower levels of exercise and, if the calculated extraction value assumptions still hold at lower SaO2 values, reduced for the higher work rates at intermediate altitudes. The present study confirms constancy of oxygen extraction and hence the ratio of oxygen delivery to oxygen consumption (1/E), within physiological limits, and appears to show where those limits lay and, to some extent, show how matters change beyond ordinary physiological limits. [ABSTRACT FROM AUTHOR]

The total amount of blood flow circulating through the heart, lungs and all the tissues of the body represents the cardiac output. Most individual tissues determine their own flow in proportion to their metabolic rate. The skin is a notable exception where the priority is thermal rather than metabolic. Renal blood flow and metabolic rate are related but plasma flow determines metabolic rate rather than metabolic rate determining blood flow. 1 Brain, heart, skeletal muscle and the splanchnic area all vary their blood flows according to local tissue metabolic rate. Summation of peripheral blood flows constitutes venous return and hence cardiac output. Cardiac output is therefore, largely, determined by the metabolic rate of the peripheral tissues; the heart ‘from a flow standpoint, plays a "permissive" role and does not regulate its own output'. 2 This peripheral tissue, largely metabolic, determination of cardiac output has been known for many years. 3,4 [ABSTRACT FROM AUTHOR]

The aim of the present experiment was to determine whether a single 30 s of exposure to -2 G z (foot-to-head inertial forces) as orthostatic stress results in altered brain oxygenation control in response to active standing. Cerebral oxygenation (oxy-Hb), cerebral blood volume (CBV), and mean arterial blood pressure at brain level (MAP brain) were recorded in 12 subjects in supine and then in standing position (10 min), before and after -2 G z centrifugation. The decrease in oxy-Hb (-5 ± 9 vs -9 ± 10 μ M, P 0.001) and in CBV (-2 ± 11 vs -4 ± 12 μ M, P 0.05) upon standing was more important after -2 G z centrifugation, with unchanged MAP brain (-6 ± 7 vs -6 ± 9 mmHg). These findings suggest a downward shift in the static cerebral autoregulation curve. [ABSTRACT FROM AUTHOR]

In the microenvironment of solid growing tumors, pronounced hypoxia or extracellular acidosis is commonly found The aim of this study was the analysis of the cytotoxic effect of different chemotherapeutic agents (cisplatin, daunorubicin, docetaxel) under these conditions in vitro Prostate carcinoma cells (R3327-AT1) were exposed to hypoxia (pO 2 05 mmHg) or extracellular acidosis (pH=66) for 6h After 3h, cytotoxic drugs were added The cytotoxic effect was assessed by measuring caspase 3-activity (apoptosis), LDH release (necrosis) and repopulation of the cells after chemotherapy (cell death) Compared to aerobic control conditions, severe hypoxia over 6h per se led to a slight increase in apoptosis, necrosis and cell death With all three chemotherapeutic agents, hypoxia led to a reduced (by approx 25%) caspase 3-activity and a marked increase in necrosis However, the overall cytotoxicity of the drug was not affected by O 2 -deficiency By contrast, during extracellular acidosis, the cytotoxic effect of daunorubicin was reduced by 40%, preferentially due to a marked reduction in apoptosis With cisplatin and docetaxel no change in overall cell death was detected However, for daunorubicin the tumor-pH seems to have a strong impact on cytotoxicity With this chemotherapeutic drug the therapeutic efficacy is markedly reduced in an acidotic environment [ABSTRACT FROM AUTHOR]

Endostatin, a fragment of the C-terminal domain of mouse collagen XVIII, is a recently demonstrated endogenous inhibitor of tumor angiogenesis. Although endostatin can be detected in blood and urine of tumor-bearing as well as normal mice, the exact localization of the endogenous protein and its related peptides in tumor tissues is unknown. We used immunohistochemistry and immunoblotting to identify endostatin tissue location and staining patterns in tumor, as well as to determine the differences in the levels of endostatin expression between tumor cells (in vitro) and tumor tissues (in vivo). Using a specific polyclonal antibody against murine endostatin, we quantitatively determined the levels of endostatin in five murine mammary tumors and the KHT sarcoma by Western blotting. The staining patterns for this protein in tumor sections were examined histologically by immunohistochemistry. Our results show that: 1) Endogenous endostatin and its related peptides are widely distributed in all in vivo tumor types tested, but not in most of the cultured tumor cell lines. 2) Endogenous endostatin stained most tumor stromal components, including vessel walls, basement membranes, extracellular spaces, and tumor cells. 3) Staining patterns and localization of endostatin and thrombospondin-1 were similar in these tumor sections. [ABSTRACT FROM AUTHOR]

Triptolide (TPL), a small molecule purified from the herb Tripterygium wilfordii, has potential clinical application for suppression of chronic autoimmune disorders and inhibition of tumor growth. However, its mechanism of action is largely unknown. In this study, the effect of TPL on mitochondria was explored with a panel of molecular probes that detect the alteration of mitochondrial functions. When Lewis lung carcinoma (LLC) cells were treated with different doses of TPL for four hours, impaired mitochondrial functions were detected. This included an increased production of reactive oxygen species, the opening of the transition pore of mitochondria, the depolarization of the mitochondria membrane, the inhibition of the production of ATP and increased release of ATP as well as the induction of apoptosis. It is likely that by impairment of mitochondrial function, TPL exerts its inhibitory effect on growth of tumor and progression of inflammatory disease. [ABSTRACT FROM AUTHOR]

Persistent Hyperinsulinemic Hypoglycaemia of Infancy (PHHI) is a metabolic syndrome of unregulated insulin secretion. It is a heterogenous disease with causes linked to mutations of the ATP sensitive potassium channels of the β cell, as well as to metabolism in the β cell. 5 candidate genes - ABCC8, KCNJ11, GCK, GLUD1 and SCHAD have been implicated in the disease so far, however the aetiology of the disease remains unknown in up to 50% of all patients. We genotyped 43 subjects with PHHI (20 surgically treated and 23 medically treated) for disease associated mutations in the candidate genes. Mutations on ABCC8 were identified in 16 of the 20 (80%) of the surgically treated patients. One putative mutation was identified in the medically treated cohort. The polymorphism E23K on KCNJ11 that is associated with NIDDM was differentially distributed in the 2 cohorts. We discuss the mutations identified, emphasise the importance of the K-ATP channel in physiological processes and discuss the possibility that the disease is caused by mutations in other genes associated with insulin release, glucose metabolism in the β cell or β cell apoptosis and survival. We propose that these processes must be explored in order to further our understanding of PHHI. [ABSTRACT FROM AUTHOR]

Human protein C (PC) is a natural anticoagulant, antithrombotic, anti-inflammatory, and anti-apoptotic in the bloodstream. PC deficiency can lead to abnormal blood clot formation inside blood vessels, possibly causing heart attack, stroke, skin necrosis, or even death. PC can be, therefore, a valuable therapeutic with little side effect, unlike the currently used anti-coagulants. To reduce the cost involved in immuno purification of PC from blood plasma, single chain variable fragments (mini-Mab) are being produced by recombinantE. coli using phagemid technique. As an economic means of purifying the PC specific mini-Mab, metal affinity chromatography (IMAC) purification process was also investigated. Then using the purified mini-Mab, the feasibility of PC purification from the Cohn Fraction IV-1 was examined. Cohn Fraction IV-1 is usually a discarded side-stream from the blood plasma fractionation of human serum albumin. It holds 90% of PC in plasma, but is very cheap. Preliminary study of PC purification from the Cohn Fraction IV-1 showed 16% purification yield using mini-Mab immobilized NHS-activated Sepharose. The economic analysis for PC purification using mini-Mab showed that the overall process was found to be tens of times cheaper than that using Mab. [ABSTRACT FROM AUTHOR]

Increasing efforts have been directed towards investigating the involvement of nitric oxide (NO) for normal kidney function. Recently, a crucial role of NO in the development of progressive renal dysfunction has been reported during diabetes and hypertension. Indirect estimation of renal NO production include urinary nitrite/nitrate measurements, but there are several disadvantages of indirect methods since production and bioavailability of NO rarely coincide. Thus, direct measurement of in vivo NO bioavailability is preferred, although these methods are more time consuming and require highly specialized equipment and knowledge. This review focuses on two techniques for in vivo measurement of bioavailable NO in the kidney. We have applied Whalen-type recessed NO microsensors for measurement of NO in the kidney cortex, whereas the hemoglobin-trapping technique seems to be more suitable for NO measurement in the renal medulla. Both methods are robust and reliable, and we discuss advantages and shortcomings of each method. [ABSTRACT FROM AUTHOR]

With the advent of easy access to the human genome sequence, molecular biology techniques to target respirome-specific genes have begun to be exploited in the study of human disorders and in particular human cancers. In some recent publications it would appear that some investigators have inappropriately targeted pseudogenes rather than functional genes. The high transcription level and generally small size of many of the genes in the respirome make them prone to duplications in the form of processed pseudogenes within the human genome. Such genes can be challenging to analyse using standard molecular genetics approaches. In this presentation, we offer an analysis of pseudogenes that have been identified to have significant homology with some elements of the respirome. Other sequence elements such as Alu repeats, which present similar research obstacles, are also discussed. [ABSTRACT FROM AUTHOR]

Recently, a combined probe has been developed capable of simultaneous measurement of local tissue pO2 (fluorescence oximetry) and microvascular perfusion (laser Doppler flux) within the same local region. The aim of the current study was to test the utility of these combined probes to measure pO2 and perfusion in the kidney. Studies were performed in anesthetized, artificially ventilated rabbits (n=7). Baseline measurements of renal medullary perfusion and pO2 obtained using combined probes (537± 110 units & 28.7± 6.1mmHg, respectively) were indistinguishable from those obtained using independent probes (435± 102 units & 26.9± 6.4mmHg). Baseline measurements of renal cortical pO2 were also similar between combined (9.7± 1.6mmHg) and independent probes (9.5± 2.3mmHg). Baseline levels of cortical perfusion however, were significantly greater when measured using independent probes (1130± 114units) compared to combined probes (622± 59units; P<0.02). Relative changes in perfusion and pO2 resulting from graded stimulation of the renal nerves were not significantly different when measured using combined probes to those obtained using independent probes. We conclude that combined probes are equally suitable to independent probes for tissue pO2 and microvascular perfusion measurement in the kidney. Our results raise some concerns regarding the accuracy of these OxyLite fluorescence probes for pO2 measurement in the kidney, particularly within the renal cortex. [ABSTRACT FROM AUTHOR]

Wyman's equation of 1966 1 describes the facilitation of flux of a reversibly bound substrate such as oxygen, consequent on the translational diffusion of the binding protein (the carrier). While Wyman's equation 1, or some modification of it such as that by Murray 2, may provide a realistic description of the flux of oxygen through a dilute solution of haemoglobin (see also Wittenburg 3, 4), it is unlikely to be the complete explanation, nor even the basis, for oxygen transport through the intact red cell. The mature erythrocyte contains approximately 350g/l haemoglobin, and while this suggests that only 35% of the available water volume is actually occupied by the protein, the remaining 65% is unavailable for protein translational diffusion due to the mutual exclusion of the haemoglobin molecules. For this reason we have examined other possible mechanisms whereby haemoglobin may facilitate the translational diffusion of oxygen within the erythrocyte. Possible alternatives include rotational diffusion by the haemoglobins, intracellular shuffling of haemoglobins due to shape changes by the erythrocyte, and haemoglobin rotations and oxygen exchange consequent on the charge change which accompanies substration and desubstration of the haemoglobin molecule. Finally the dipole interactions are shown to generate significant intermolecular attractions between adjacent haemoglobins. [ABSTRACT FROM AUTHOR]

Accurate prediction of tumor metastatic potential would be helpful in treatment planning and in the design of agents that modify the tumor phenotype. We report that three methods that are potentially transferable to the clinic - dynamic contrast enhanced MRI (DCE MRI), T1ρ-weighted imaging and low temperature fluorescence imaging (that could be performed on biopsy specimens) - distinguished between relatively indolent (A375P) and aggressive (C8161) metastatic human melanoma xenografts in nude mice, whereas T1 and T2 relaxation time measurements did not. DCE MRI data analyzed by the BOLus Enhanced Relaxation Overview (BOLERO) method in conjunction with concurrent measurements of the arterial input function yielded a blood transfer rate constant (Ktrans) which measures perfusion/permeability, that was significantly higher in the core of the indolent tumor than in the core of the aggressive tumor. Histological staining indicated that aggressive tumors had more blood vascular structure but fewer functional vascular structure than indolent tumors. Indolent tumors exhibited T1ρ values that were significantly higher than those of aggressive tumors at spin-locking frequencies >500Hz. The mitochondrial redox ratio, Fp/(Fp+NADH), where Fp and NADH are the fluorescence of oxidized flavoproteins and reduced pyridine nucleotides, respectively, of aggressive tumors was much higher (more oxidized) than that of indolent tumors and often showed a bimodal distribution with an oxidized core and a reduced rim. These differences observed between these two types of tumors, one indolent and one aggressive, if generalizable, would be very valuable in predicting human melanoma metastatic potential. [ABSTRACT FROM AUTHOR]

The incidence of Squamous Cell Carcinoma (SCG) is growing in certain populations to the extent that it is now the most common skin lesion in young men and women in high ultraviolet exposure regions such as Queensland. In terms of incidence up to 40% of the Australian population over 40 years of age is thought to possess the precancerous Solar Keratosis (SK) lesion and with a small, but significant, chance of progression into SCC, understanding the genetic events that play a role in this process is essential. The major aims of this study were to analyse whole blood derived samples for DNA aberrations in genes associated with tumour development and cellular maintenance, with the ultimate aim of identifying genes associated with non-melanoma skin cancer development. More specifically the first aim of this project was to analyse the SDHD and MMP12 genes via Dual-Labelled Probe Real-Time PCR for copy number aberrations in an affected Solar Keratosis and control cohort. It was found that 12 samples had identifiable copy-number aberrations in either the SDHD or MMP12 gene (this means that a genetic section of either of these two genes is aberrantly amplified or deleted), with five of the samples exhibiting aberrations in both genes. The significance of this study is the contribution to the knowledge of the genetic pathways that are malformed in the progression and development of the pre-cancerous skin lesion Solar Keratosis. [ABSTRACT FROM AUTHOR]

The cytotoxic RNase, Onconasemboxtextregistered (ONC), isolated from amphibian oocytes, was used to study its effect on the radiation response in A549 human NSCLC in vitro and in vivo. In cell culture studies, we found that ONC increased the radiation response by ONC-induced inhibition of O2 consumption (QO2). The occurrence of apoptosis was increased by ONC and was dependent on dosages and time exposure (measured by a Tunnel in situ cell death detection assay). Moreover, ONC inhibited sublethal damage repair (SLDR), confirmed by a split dose experiment. In animal studies, ONC significantly increased the radiation-induced tumor growth delay of A549 tumors in vivo. Using a non-invasive DCE-MRI technology, ONC-induced changes of perfusion were observed in A549 tumors. We concluded that the ONC-induced enhancement in tumor oxygenation was mainly due to the reduction in QO2 rather than an increase in tumor blood flow. This investigation suggests important potential clinical uses of ONC for the treatment of NSCLC cancer patients. [ABSTRACT FROM AUTHOR]

Cohn Fraction IV-1 (CFIV-1) is a by-product (often discarded) of a plasma fractionation process. It retains 90% of Protein C (PC) of plasma but contains several coagulants structurally homologous to PC. Of these coagulants, Factor II (FII) has the longest half-life (12 times of PC) and largest quantity (9 times of PC) in CFIV-1. Current purification process for PC is by immunoaffinity chromatography using monoclonal antibodies, which is very expensive. Immobilized metal affinity chromatography (IMAC) is an inexpensive process that uses metal ions to adsorb proteins via their surface histidines. Affinity of PC to the metal ions in IMAC is higher than that of FII because PC has 15 surface histidines and FII has 5. Two important factors in an IMAC process are pH and imidazole concentration. PH controls protonation of histidine, and imidazole, a histidine analog, competitively reacts with metal ions. The effects of pH and imidazole on adsorption and elution of PC and FII during IMAC process were studied. The effect of pH on PC and FII adsorption was similar within the range of 6.0 and 8.0. At concentrations below 15 mM imidazole, little PC or FII eluted. At 15 and 20 mM imidazole 2.5% of PC was eluted, while 20-30% of FII was eluted. [ABSTRACT FROM AUTHOR]

Low heat (42∼ 45oC) hyperthermia is an effective cancer therapy with few side effects. Well engineered nanoparticles can effectively guide heat to the tumor without damaging the normal tissue. When nano-sized particles are injected to an organ with a tumor, they tend to accumulate in the tumor due to the unorganized nature of its vasculature. Magnetic nanoparticles, such as Fe3O4, are heated by a well selected alternating electromagnetic frequency. At a frequency of 450 KHz or lower, Fe3O4 nanoparticles at a size of 10∼ 30 nm were heated effectively, without heating tissue main components. Gold nanoparticles are known as strong near infrared (NIR) absorbers. Nanogold particles at a diameter of 150 nm were added at 0.01wt% to the tumor model, placed at depths of 1∼ 2.5 cm, in an optically equivalent experimental breast model. Then the surface of the breast model was scanned with NIR light at 788 nm. The particles in the tumor model increased the optical contrast of the tumor by 1∼ 3.5dB. Considering that some of the FDA approved MRI contrast agents are made of Fe3O4, gold-coated Fe3O4 particles have a potential to be used as safe optical and thermal markers, allowing seamless breast cancer detection and cancer-specific hyperthermic treatment. [ABSTRACT FROM AUTHOR]

Final results of an investigation into whether oxygen saturation of tissues (StO2, measured by spectrophotometry) could predict surgical site infections (SSI) after major abdominal surgery are presented StO2 was measured on the arm and wound site pre-operatively and then at 12, 24 and 48 hours post-operatively. A Whitland Research RM200 was employed as the visible lightguide spectrophotometer. StO2 measurements using this machine were designated SSO2 (skin SO2). A Hutchinson Inspectra® Model 325 was used for the near infrared spectroscopy (NIS) measurements. StO2 measurements using this machine were designated MSO2 (muscle SO2). Of 59 patients (38 males, 21 females), 42 healed uneventfully and 17 developed SSI. The overall infection rate was 28.8%. No significant differences were seen in wound SSO2 between outcome groups at any stage. At 12 hours there was a significant difference between the two groups with respect to mean wound MSO2 (A= 58.3+/-21.6%, B=42.2+/-16.6%, p=0.005, 95% confidence interval = 5.26, 26.98). A receiver operating characteristic curve showed that when a wound MSO2 of 53% was chosen as the threshold to classify potential infection a sensitivity of 71% and a specificity 73% (chi-squared test, p=0.002) was achieved. The use of the near-infrared spectrophotometry as a tool to predict wound infections should be further evaluated and advocated. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) is the leading cause of death in US. Early and accurate diagnosis of CVD is crucial to save many lives, especially for the patients suffering the heart attack. Accurate and fast quantification of cardiac muscle specific biomarkers in the blood enables accurate diagnosis and prognosis and timely treatment of the patients. A prototype of fiber-optic, multi-analyte, immuno-biosensing system integrated with an automatic flow control unit has been in development to quantify four important cardiac markers in blood plasma accurately, rapidly and simultaneously. The validity of the sensor was, however, challenged because the concentrations of two markers are only at tens of picomolar level. Here, plasmon rich nano-metallic particles and selected biocompatible solvents were developed for fluorescence enhancement to improve the sensitivity of our fluorophore mediated biosensing. By applying the nano-metal particle and the solvent, the sensitivity of single cardiac marker sensors were increased by 1.5 ∼ 3 times. By using the fluorescence enhancing nano-metallic particle reagents, simultaneous quantification of four cardiac markers in plasma is currently possible, using 3-cm-sensor within 10 minutes at an average signal-to-noise ratio of 20. [ABSTRACT FROM AUTHOR]

Cervical cancer is one of the world's major health issues. Despite many studies in this field, the carcinogenetic events of malignant conversion in cervical tumours have not been significantly characterised. The first aim of this project was to investigate the mutation status of the tumour suppressor gene- Phosphatase and Tension Homolog (PTEN)- in cervical cancer tissue. The second aim of this study was the analysis in the same cervical cancer tissue for aberrations in the mitochondrial electron transport chain subunit gene NDUFB8, which is localised to the same chromosomal contig as PTEN. The third aim was the evaluation of the potential therapeutic anti-cancer drug 2,4-Thiazolidinediones (TZDs) and its affect in regulating the PTEN protein in a cervical cancer cell line (HeLa). To approach the aims, paraffin-embedded cancerous cervical tissue and non-cancerous cervical tissue were obtained. DNA recovered from those tissues was then used to investigate the putative genomic changes regarding the NDUFB8 gene utilising SYBR Green I Real-Time PCR. The PTEN gene was studied via Dual-Labelled probe Real-Time PCR. To investigate the protein expression change of the PTEN protein, HeLa cells were firstly treated with different concentrations of 2,4-Thiazolidinediones and the level of PTEN protein expression was then observed utilising standard protein assays. Results indicated that there were putative copy-number changes between the cancerous cervical tissue and non-cancerous cervical tissue, with regard to the PTEN locus. This implies a potential gain of the PTEN gene in cancerous cervical tissue. With regards to normal cervical tissue versus cancerous cervical tissue no significant melting temperature differences were observed with the SYBR Green I Real-Time PCR in respect to the NDUFB8 gene. A putative up-regulation of PTEN protein was observed in TZD treated HeLa cells. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the impact of clonidine on mucosal red cell flux during baseline sedation with propofol or sevoflurane, respectively. Materials and Methods:Six healthy, chronically instrumented dogs for the measurement of cardiac output (CO) were repeatedly studied. During baseline sedation with either propofol (15 mg kg -1 h -1) or sevoflurane (1.5 MAC), local tissue cell flux was assessed using laser Doppler flowmetry at the enoral mucosa. After baseline measurements, a bolus of clonidine (2.0 μ g/kg) was infused within 1 min. Data are presented as mean ± SEM; Statistics: ANOVA, Scheffé's post hoc test, p < 0.05. Results:Clonidine significantly reduced CO from 75 ± 4 and 75 ± 6 ml kg -1 min -1 (sedation with propofol or sevoflurane, respectively) to 40 ± 3 and 49 ± 5 ml kg -1 min -1 , however, with almost complete recovery to baseline after 30 min (70 ± 4 and 71 ± 6 ml kg -1 min -1 , NS from baseline). Similarly, clonidine decreased mucosal red cell flux by 44 ± 8% and 54 ± 4%. However, mucosal perfusion did not return to baseline (-25 ± 5% and -27 ± 3%). Conclusions:In spite of the rapid return to baseline in systemic perfusion, the mucosal red cell flux of the enoral mucosa remained markedly reduced after a single bolus of clonidine. Given the crucial role of preserved microcirculatory perfusion for an intact mucosal barrier function, our data suggest that clonidine might impair this important mechanism to prevent the translocation of bacteria and endotoxins into the systemic circulation. [ABSTRACT FROM AUTHOR]

We evaluated morphological changes in several pathologies using computerized videocapillaroscopy, and related hemorheological patterns using the laser assisted optical rotational red cell analyzer (LORCA). In addition, tissue oxygenation was measured using two oximeters with Combi sensors (Periflux 5000, Perimed). The study included four groups of patients (pts) that were compared with a control group. Group AControls (n=25: 15 males [M] and 10 females [F] aged 36 ± 3 years); Group BDiabetic pts n=32 (IDDM pts n=20: 12 M and 8 F aged 43 ± 4 years; NIDDM pts n=12: 6 M and 6 F aged 45 ± 3 years); Group CGlaucoma pts n=30 (16 M and 14 F aged 42 ± 5 years); Group DLiver failure pts n=6 (3 M and 3 F aged 44 ± 5 years); Group EHypertensive pts n=50 (smokers n=28: 12 M and 16 F aged 40 ± 4 years, and non-smokers n=22: 12 M and 10 F aged 38 ± 3 years). In all patients hemorheological measurements were made using the LORCA (including red blood cell [RBC] deformability and aggregability), morphology was evaluated using computerized videocapillaroscopy (magnification 200 x), and transcutaneous oxygen partial pressure measurements (TcpO 2) were made with the Periflux 5000. In patients with diabetic microangiopathy: the capillary loops in 50% (16/32) of these pts showed formations such as ‘deer horns', 72% (23/32) showed formations such as ‘elephant nose', and in 45% (14/32) formations such as a ‘cork screw'; in diabetics with POAD an important capillary rarefaction was found in 26% (9/32) of the pts. In glaucoma patients, in 84% (25/30) we observed ‘capillary meandering' and images such as ‘a comb'. In patients with more complicated pathology capillary rarefaction was found in 70% (21/30) of the patients. An improvement in the perfusion of non-functional loops was found in deceased patients who had suffered liver failure one week after liver transplantation in 90% (5/6) of the studied cadavers. In non-smoking hypertensives morphological changes were found in 25% (6/22) of the patients, and in hypertensive smokers in 47% (13/28). RBC deformability was detected using LORCA and expressed as the Elongation Index (EI), and RBC aggregability was detected using LORCA and expressed in t ½(seconds) indicating the RBC aggregability peak. Group A controls: EI 0.59 ± 0.02; t 3 ± 1 sec; Group B: IDDM EI 0.55 ± 0.01; t : 2 ± 0.5 sec p <0.05; NIDDM EI 0.56 ± 0.01; t 2 ± 0.2 sec p < 0.04; Group C glaucoma: EI 0.56 ± 0.01; t 2 ± 0.3 sec p < 0.05; Group D liver failure: EI 0.56 ± 0.02; t 2 ± 0.4 sec p < 0.03; Group E hypertensives: smokers EI 0.56 ± 0.02; t 2 ± 0.6 sec p < 0.04; non-smokers EI 0.57 ± 0.02; t 2 ± 0.6 sec p < 0.04 compared with controls. We also measured the TcpO 2 at the dorsum of the right foot as a standard site representing peripheral control of microvasculature perfusion. Group A 96 ± 11 mmHg; Group B IDDM 74 ± 9 mmHg p < 0.05; NIDDM 76 ± 8 mmHg p < 0.05; Group C glaucoma 75 ± 9 mmHg p < 0.05; Group D liver failure 69 ± 6 mmHg p < 0.05; Group E hypertensives: smokers 70 ± 5 mmHg p < 0.05, non-smokers 77 ± 9 mmHg p < 0.05 compared with controls. This study presents an interesting and complete methodology to evaluate the microcirculation in different pathologies that induce changes in the microvasculature. [ABSTRACT FROM AUTHOR]

Anti-coagulant proteins are essential to maintain blood hemostatis for the supply of oxygen and nutrients to tissue cells and for the removal of toxic by-products from metabolism. Hereditary or acquired deficiencies of Protein C, Protein S, or Anti-thrombin III can lead to disease states such as deep vein thrombosis (DVT) with the possibility of producing lung emboli. Phenomena named Factor V Lieden can produce a similar pathologic condition. Anti-coagulant deficiencies, including Factor V Lieden, are HIDDEN blood conditions that can allow blood clot development, especially with trauma to the tissue and circulatory system. It is proposed that all children between ages twelve to fourteen be checked hereditary deficiencies and Factor V Lieden complications. This would require the development of inexpensive assay equipment12. The present research focuses on the low cost production of Zymogen Protein C via purification from blood plasma Cohn Fraction IV-1. This process is difficult due to the several Homologous Vitamin K dependent proteins in the blood coagulation cascade. Traditional chromatography (ion exchange) cannot achieve the desired separation. Some more exotic technologies are very expensive so our work proposes to use Immobilized Metal Affinity Chromatography (IMAC). It is hoped to produce a lower cost product that can be used prophylactic ally to treat Protein C deficiencies and possibly other coagulation problems. [ABSTRACT FROM AUTHOR]

A single compartment model of the arterial circulation was used to generate an arterial blood pressure waveform from pre-determined stroke volume (SV) and arterial resistance (R). With fixed stroke volume and varying resistances blood pressure waveforms showed mean values proportional to resistance but amplitude lessening with higher pressure; the amplitude of the hypothetical volume waveform of the arterial system was the same for all resistance values. Where SV varied and R changed reciprocally, the waveform when analysed with the PulseCO™ algorithm gave estimates slightly higher than the input stroke volumes (r 0.9998; y=0.99x + 5.28 ml). Where SV varied with fixed R mean blood pressure varied with stroke volume; SV estimates were, again, slightly higher than the input stroke volumes (r 0.9994; y=0.986x + ml). Estimates of SV andRfromValsalva manoeuvre BP were used in the model to generate arterial blood pressure. SV estimates closely resembled the original model values (r 0.988; y = 1.0802x − 3.9251). The model appears capable of generating BP waveforms compatible with real BP waveforms since stroke volume estimates closely resemble the original stroke volumes used in the model. [ABSTRACT FROM AUTHOR]

A new Oxyphor (Oxyphor G3) has been used to selectively determine the oxygen pressure in interstitial (pericellular) spaces. Oxyphor G3 is a Pd-tetrabenzoporphyrin, encapsulated inside generation 2 poly-arylglycine (AG) dendrimer, and therefore is a true near infrared oxygen sensor, having a strong absorption band at 636nm and emission near 800nm. The periphery of the dendrimer is modified with oligoethylene glycol residues (Av. MW 350) to make the probe water soluble and biologically inert. Oxyphor G3 was injected along 'tracks' in the tissue using a small needle (30gage or less) and remained in the pericellular space, allowing oxygen measurements for several hours with a single injection. The oxygen pressure distributions (histograms) were compared with those for Oxyphor G2 in the intravascular (blood plasma) space. In normal muscle, in the lower oxygen pressure region of the histograms (capillary bed) the oxygen pressure difference was small. At higher oxygen pressures in the histograms there were differences consistent with the presence of high flow vessels with oxygen pressures substantially above those of the surrounding interstitial space. In tumors, the oxygen pressures in the two spaces were similar but with large differences among tumors. In mice, anesthesia with ketamine plus xylazine markedly decreased oxygen pressures in the interstitial and intravascular spaces compared to awake or isoflurane anesthetized mice. [ABSTRACT FROM AUTHOR]

Near-infrared spectroscopy (NIRS) has been used to measure changes in cerebral oxy- and deoxy- haemoglobin (δ[HbO2], δ[HHb]) in response to functional activation. It has been previously reported that during functional activation of the motor cortex heart rate increases. The aim of this study was to investigate systemic changes during functional activation of the frontal cortex. The responses to anagram presentations with varying difficulty (4-Letters and 7-Letters) over a 6 minute period were recorded. A Hamamatsu NIRO 200 NIRS system recorded δ[HbO2] and δ[HHb] using the modified Beer Lambert law (MBL) and tissue oxygenation index (TOI) employing spatial resolved spectroscopy (SRS) over the left and right frontal hemisphere. Mean blood pressure (MBP) and heart rate (HR) were measured continuously. Nine young healthy volunteers (mean age 23) were included in the analysis. Significant task related changes were observed in both the NIRS and systemic signals during the anagram solving with increases in [HbO2] and [HHb] accompanied by changes in MBP and HR. The [HbO2] and [HHb] signals measured over the frontal region were found to have a varying association with the MBP signal across different volunteers. The effect of these systemic changes on measured NIRS signals must be considered [ABSTRACT FROM AUTHOR]

Recent advances in near-infrared spectroscopy (NIRS) allow measurements of absolute tissue oxygen saturation (TOI) using spatially resolved spectroscopy (SRS), while enabling better depth sensitivity. However concerns remain regarding the relative contribution of the extracranial circulation to the cerebral NIRS TOI signal. In this study we investigated this during a period of selective rise in cerebral blood flow (CBF) produced by the administration of acetazolamide (ACZ) in 10 healthy volunteers. A two channel spectrometer (NIRO 300, Hamamatsu Photonics KK) was used to measure absolute cerebral TOI over the frontal cortex using the SRS technique using an optode spacing of 5 cm and 1.5 cm for channel 1 and 2 respectively. After ACZ administration we were able to observe a significant increase in the velocity of middle cerebral artery (Vmca, measured with the transcranial Doppler (TCD)) which was accompanied by an increase in TOI as monitored by the NIRO 300 with an optode spacing of 5 cm but not with an optode spacing of 1.5 cm. Furthermore a direct relationship was seen between the Vmca and the TOI measured at 5 cm optode spacing. This work suggests that using this commercial NIRS instrument with an optode spacing of 5 cm one is able to detect the intracranial changes. [ABSTRACT FROM AUTHOR]