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Pathophysiology of the thrombophilic state in the cancer patient.

The "hypercoagulable state" of malignancy is due to a complex interaction of tumor cells and their products with host cells, leading to various degrees of impairment of the normal defense mechanisms that ordinarily protect the host against thrombogenesis. Tumor cells can activate directly the blood clotting cascade and cause thrombosis or can induce procoagulant properties and inhibit anticoagulant properties of vascular endothelial cells, platelets, and monocytes and macrophages. In the setting of the local and systemic effects of cancer (e.g., stasis induced by prolonged bed rest and/or vascular invasion by tumor), together with iatrogenic complications of the treatment of cancer (e.g., the use of central vein catheters and angiopathic chemotherapy), this basic pathophysiology conspires to make cancer perhaps the best example of "acquired thrombophilia." In this brief review, we have attempted to describe what is currently known about the mechanisms for the hypercoagulable state of cancer and provide a summary of the evidence that indicates the many levels of defects in patients with malignancies that predispose them to thrombosis. A better understanding of the pathophysiology of thrombophilia in cancer should provide clinicians with an improved rationale for more aggressive and specific anticoagulant strategies in selected patients.

Blood Coagulation↗

Disseminated intravascular coagulation: pathophysiological mechanisms and manifestations.

Current concepts of the many complex pathophysiological mechanisms and clinical and laboratory manifestations of disseminated intravascular coagulation (DIC) are presented. Considerable attention has been devoted to interrelationships within the hemostasis system. Only by clearly understanding these extraordinarily complex pathophysiological interrelationships can the clinician and laboratory scientist appreciate the divergent and wide spectrum of often confusing clinical and laboratory findings in patients with DIC. Many therapeutic decisions are controversial and will remain so until more is published about specific therapeutic modalities and survival patterns. The future holds promise for not only newer antithrombotic agents, but also agents which will block, blunt or modify cytokine activity and the activity of vasoactive substances. Also, therapy must be highly individualized depending on the nature of DIC, age, etiology of DIC, site and severity of hemorrhage or thrombosis and hemodynamic and other clinical parameters.

Animals↗

[Modern nuclear medical diagnosis as applied pathophysiology. Basis and outlook].

In their capacity as "image-assisted functional diagnostics", methods of nuclear medicine link morphological patterns of radiology with clinical presentation. Based on pathophysiology they supply an insight into both global and regional parameters, present as basal values or as reserves. Both, single photon emission computed tomography (SPECT) or highly defined positron ECT (PET), enabled computer-assisted topographical overlay and thus an exact comparative evaluation of regional function versus morphology. In addition, PET gives access to a true physiological, absolute quantification employing process specific, carrier-free substrates. Novel tracers (markers of metabolism or perfusion, receptors or transmitter substances, monoclonal antibodies), an intraluminal transport model and the concept of buffer or working reserves aim at conducting early diagnosis, determination of disease severity and parameters that are relevant for therapy, on a level that is pathophysiologically oriented.

Brain Diseases↗

Pathophysiologic principles relevant for therapeutic procedures in persistent pulmonary hypertension of the newborn.

Though the various pathophysiologic mechanisms underlying persistent pulmonary hypertension of the newborn (PPHN) necessitate rather specific therapeutic concepts, in the majority of infants with PPHN management is mainly focused on the treatment of the symptoms respiratory failure and cardiovascular abnormalities. For the few neonates with severe PPHN who fail to respond to optimized conventional ventilatory support, high-frequency oscillatory ventilation and extracorporeal membrane oxygenation are available. Treatment of cardiovascular abnormalities should be based on knowledge of the pathophysiologic events in the heart and in the pulmonary and systemic circulation of the newborn with PPHN at least as far as these events are known or suspected based on animals studies. The primary goals of therapy in PPHN must be reduction of right ventricular afterload and support of myocardial function. In this context inhalational nitric oxide therapy may be effective as a new therapeutic strategy to decrease pulmonary vascular resistance.

Critical Care↗

Responses to corticotropin-releasing hormone in the hypercortisolism of depression and Cushing's disease. Pathophysiologic and diagnostic implications.

Primary depression can be associated with substantial hypercortisolism, thus prompting some researchers to suggest that depression shares pathophysiologic features with Cushing's disease. Clinically, depression can be difficult or impossible to distinguish from mild or early Cushing's disease that is associated with depressive features. The purpose of this study was to evaluate whether the pituitary-adrenal responses to ovine corticotropin-releasing hormone could help to clarify the mechanism of hypercortisolism in depression and in Cushing's disease and to assist in the differential diagnosis of these disorders. As compared with controls (n = 34), depressed patients (n = 30) had basal hypercortisolism (P less than 0.001) that was associated with attenuated plasma ACTH responses to ovine corticotropin-releasing hormone (P less than 0.001). This indicates that in patients with depression, the corticotroph cell in the pituitary responds appropriately to the negative feedback of high cortisol levels. In contrast, patients with Cushing's disease (n = 29) had plasma ACTH hyperresponsiveness to ovine corticotropin-releasing hormone (P less than 0.001), despite basal hypercortisolism (P less than 0.001), which indicates a gross impairment of the mechanism by which cortisol exerts negative feedback on the pituitary. Less than 25 percent of the patients with depression or Cushing's disease had peak ACTH responses that overlapped. We conclude that the pathophysiologic features of hypercortisolism in depression and Cushing's disease are distinct in each of the disorders and that the ovine corticotropin-releasing hormone stimulation test can be helpful in their differential diagnosis.

Adrenocorticotropic Hormone↗

Cellular pathophysiology and therapy of pulmonary hypertension.

The identification of several mutations of the bone morphogenetic protein receptor 2 (BMPR2) gene, a member of the transforming growth factor beta receptor family, gives hope for new insights into the pathophysiology of pulmonary hypertension. Genetic predisposition might dictate the responses of pulmonary artery fibroblasts, smooth muscle cells, and endothelial cells, as well as platelets and leukocytes, or their specific interactions with different extrinsic factors. These cells possess distinct subtypes and interact with each other. Pulmonary hypertension is associated with vasoconstriction, remodeling, and in situ thrombosis of the pulmonary arteries, but the initial events and their relationship to the genetic background are presently unknown. Current therapeutic approaches are based on our knowledge of the physiologic regulation of pulmonary artery tone, pathophysiologic changes, and our clinical experience with different treatment strategies. Beyond diuretics and anticoagulants, prostaglandins are generally accepted therapeutic agents for primary pulmonary hypertension and related diseases, whereas high-dose calcium-channel blockers are reserved for a small subset of patients, those who respond favorably to vasodilators in an acute test. Long-term intravenous prostacyclin infusion has become the most important specific therapy for primary pulmonary hypertension and associated diseases. However, this therapy is hampered by catheter complications and systemic side effects. Alternative application routes of prostacyclin or its stable analogs may avoid these problems. Inhaled application of the prostacyclin analog iloprost results in predominant pulmonary vasodilation with few systemic side effects and may possess clinical efficacy similar to that of intravenous prostacyclin. Inhaled nitric oxide is widely accepted as a screening agent for active responders to vasodilators and has a similar hemodynamic profile as inhaled iloprost, although the percentage of responders is considerably lower. However, there are unsolved toxicologic questions and practical difficulties concerning the safe long-term application of nitric oxide. Combining inhaled vasodilators with phosphodiesterase inhibitors may prolong the duration of the effects and improve the convenience of inhaled therapy for pulmonary hypertension. Therapeutic approaches in the future may aim at the transforming growth factor beta pathway and at the identification of early stages of the disease to prevent further disease progression.

Animals↗

Endometriosis and ovarian cancer: thoughts on shared pathophysiology.

BACKGROUND: Endometriosis appears to predispose to ovarian cancer. How this may occur has been little discussed. STUDY DESIGN: This article reviews the English language literature for in vitro, animal, clinical, and epidemiologic studies linking the two conditions. RESULTS: Pathology case series consistently report endometrioid and clear cell types of ovarian cancer arising from endometriotic foci. Epidemiologic studies have been consistent with this association. There are also marked similarities between the proposed etiology of ovarian cancer and the observed pathophysiology of endometriosis. Specifically, both are characterized by immune alterations. Both conditions are promoted by estrogen excess and by progesterone deficit. Finally, steroid hormones interacting with the immune system may stimulate both endometriosis and ovarian cancer. I propose that the biology common to endometriosis and ovarian cancer represents not just a parallelism, but instead a causal pathway: aberrant immune function, fed by and feeding on estrogens, unbalanced by progesterone, may create a positive feed-forward loop that enhances the growth and invasiveness of endometriosis and promotes its malignant transformation. CONCLUSIONS: The same pathophysiology may orchestrate the progression of endometriosis and its transformation to endometroid and clear cell ovarian neoplasias. This notion of a unifying biology suggests a directed approach to future research and identifies possible chemoprevention strategies for women with endometriosis.

Androgens↗

Recurrence of chronic venous ulcers on the basis of clinical, etiologic, anatomic, and pathophysiologic criteria and air plethysmography.

INTRODUCTION: Leg ulcers associated with chronic venous insufficiency (CVI) frequently recur after healing. The risk of recurrence has not been well defined for patients in different anatomic and hemodynamic groups. We reviewed the risk of ulcer recurrence on the basis of clinical, etiologic, anatomic, and pathophysiologic criteria and hemodynamic characteristics of the affected limb as assessed with air plethysmography (APG). METHODS: Ninety-nine limbs with class 6 CVI were assessed clinically and with standing duplex ultrasound scanning and APG for the definition of clinical, etiologic, anatomic, and pathophysiologic criteria. Leg ulcers were treated with high-pressure compression protocols. Surgical correction of venous abnormalities was offered to patients with appropriate conditions. After ulcer healing, the limbs were placed in compressive garments and followed at 6-month intervals for ulcer recurrence. RESULTS: The mean patient age was 54.3 years, and 46% of the patients were female. Corrective venous surgery was performed in 37 limbs. The mean follow-up time for all 99 limbs was 28 months. The ulcer recurrence rate with life table was 37% +/- 6% at 3 years and 48% +/- 10% at 5 years. The patients who underwent venous surgery had a significantly lower recurrence rate (27% +/- 9% at 48 months) than did those patients who had not undergone surgery (67% +/- 8% at 48 months; P =.005). The patients with deep venous insufficiency (DVI; n = 51) had significantly higher recurrence rates (66% +/- 8% at 48 months) than did the patients without DVI (n = 48; 29% +/- 9% at 48 months; P =.006). This difference was significant even after accounting for the effects of surgery (P =.03). The hazard ratio of ulcer recurrence increases by 14% for every unit increase in the venous filling index (VFI; P =.001). This remains significant even after accounting for the effects of surgery (P =.001). The combination of DVI and a VFI of more than 4 mL/s yields a risk of ulcer recurrence of 43% +/- 9% at 1 year and 60% +/- 10% at 2 years. CONCLUSION: Leg ulcers associated with CVI have a high rate of recurrence. Ulcer recurrence is significantly increased in patients with DVI and in patients who do not have venous abnormalities corrected surgically. The VFI obtained from APG is useful in the prediction of increased risk for recurrence, particularly in association with anatomic data.

Bandages↗

Secreted proNGF is a pathophysiological death-inducing ligand after adult CNS injury.

The unprocessed precursor of the neurotrophin nerve growth factor (NGF), proNGF, has been suggested to be a death-inducing ligand for the neurotrophin receptor p75. Whether proNGF is a true pathophysiological ligand that is secreted, binds p75, and activates cell death in vivo, however, has remained unknown. Here, we report that after brain injury, proNGF was induced and secreted in an active form capable of triggering apoptosis in culture. We further demonstrate that proNGF binds p75 in vivo and that disruption of this binding results in complete rescue of injured adult corticospinal neurons. These data together suggest that proNGF binding to p75 is responsible for the death of adult corticospinal neurons after lesion, and they help to establish proNGF as the pathophysiological ligand that activates the cell-death program by means of p75 after brain injury. Interference in the binding of proNGF to p75 may provide a therapeutic approach for the treatment of disorders involving neuronal loss.

Animals↗

A novel pathophysiological mechanism for osteoporosis suggested by an in vivo gene expression study of circulating monocytes.

Bone mineral density (BMD) is a major risk factor for osteoporosis. Circulating monocytes may serve as early progenitors of osteoclasts and produce a wide variety of factors important to bone metabolism. However, little is known about the roles of circulating monocytes in relation to the pathophysiology of osteoporosis. Using the Affymetrix HG-U133A GeneChip(R) array, we performed a comparative gene expression study of circulating monocytes in subjects with high and low BMD. We identified in total 66 differentially expressed genes including some novel as well as some already known to be relevant to bone metabolism. Three genes potentially contributing to bone metabolism, CCR3 (chemokine receptor 3), HDC (histidine decarboxylase, i.e. the histamine synthesis enzyme), and GCR (glucocorticoid receptor), were confirmed by quantitative real-time reverse transcriptase-PCR as up-regulated in subjects with lower BMD. In addition, significant negative correlation was observed between expression levels of the genes and BMD Z-scores. These three genes and/or their products mediate monocyte chemotaxis, histamine production, and/or sensitivity to glucocorticoids. Our results suggest a novel pathophysiological mechanism for osteoporosis that is characterized by increased recruitment of circulating monocyte into bone, enhanced monocyte differentiation into osteoclasts, as well as osteoclast stimulation via monocyte functional changes. This is the first in vivo microarray study of osteoporosis in humans. The results may contribute to identification of new genes and their functions for osteoporosis and suggest genetic markers to discern individuals at higher risk to osteoporosis with an aim for preventive intervention and treatment.

Aged↗

Initiation and regulation of CD8+T cells recognizing melanocytic antigens in the epidermis: implications for the pathophysiology of vitiligo.

Antigen-specific CD8+T lymphocytes play an important role in defense against cutaneous microbial infection and skin cancer as well as in the pathophysiology of autoimmune skin disease such as lupus erythematodes and vitiligo. We have explored the role of CD8+ cytotoxic T lymphocytes (CTL) in an experimental mouse model of vitiligo, a pigmentation disorder characterized by focal loss of melanocytes in the skin. Using genetic immunization techniques we found that pigment cells in the epidermis can be destroyed by CD8+ T cells specifically recognizing a single H2-Kb-binding peptide derived from the model melanocytic self antigen tyrosinase-related protein 2 (TRP2), a melanosomal enzyme involved in pigment synthesis. Experimental evidence suggests that peripheral tolerance of pigment cell-specific cytotoxic CD8+T cells is regulated in two steps. In the induction phase, stimulation and expansion of these T cells in vivo strictly depends on CD4+ T cell help. In the effector phase, autoimmune destruction of melanocytes in the skin depends on local inflammation facilitating the migration of T cells into the epidermis and supporting effector functions. Our results suggest that accidental stimulation of CD8+ CTL recognizing MHC class I-binding peptides derived from melanocytic proteins in the context of an inflammatory skin disease may play an important role in the pathophysiology of vitiligo. Further investigations will address the role of chemokines, chemokine receptors and adhesion molecules in this experimental system and will reveal the role of keratinocytes and Langerhans cells in regulating cutaneous CD8+ T cell responses.

Animals↗

Essential hypertension. Matching pathophysiology and pharmacology.

The underlying pathophysiologic mechanisms that elevate arterial pressure differ according to the patient's age, adipose body mass, and race. However, these mechanisms represent the extremes of a continuum, and overlap among them can be encountered in some patients. A few simple clinical clues allow the physician to identify whether an increase in cardiac output, total peripheral resistance, or both is the predominant mechanism in a given patient. Antihypertensive therapy should be aimed not only at lowering arterial pressure but also, more importantly, at ameliorating the concomitant pathophysiologic abnormality. A beta-adrenoreceptor blocker is the initial drug of choice in young patients with "cardiogenic hypertension." In middle-aged patients, cardiac output is usually normal and elevated total peripheral resistance becomes the hemodynamic culprit. In these patients, an angiotensin-converting enzyme (ACE) inhibitor, antiadrenergic drug, or calcium channel blocker should be given to lower total peripheral resistance without affecting cardiac output. In elderly patients, the burden on the heart should be lessened by use of an agent that lowers preload and afterload, such as an ACE inhibitor or certain of the calcium blockers. In obese patients in whom intravascular volume is expanded and in most black patients, the initial antihypertensive agent of choice remains a thiazide diuretic unless left ventricular hypertrophy is present.

Adolescent↗

Stress incontinence observed with real time sonography and dynamic fastscan magnetic resonance imaging--insights into pathophysiology.

Our concepts of pathophysiology of stress urinary continence have been greatly shaped by developments in radiographic imaging. Simple radiographs with and without contrast initially revealed the importance of urethral descent in pathogenesis. More recently, magnetic resonance imaging (MRI) and real time ultrasonography are showing soft tissue detail within both a global pelvic and a local urethral context. Careful examination of these studies can extend our concepts of pathophysiology and lead us beyond existing paradigms. We propose a unified theory of stress incontinence based on our dynamic fastscan MRI and real time ultrasonograms of stress incontinence, incorporating known details of pelvic anatomy, sphincteric location and function. The hypothesis introduces the concept of a continence threshold at which the urethra is subjected simultaneously to both shearing and explusive forces. If these forces are sufficient to overcome urethral coaptation at threshold, leakage results. The model proposes an anatomical sequence of changes through which the incontinent urethra cycles between periods of rest and increased abdominal pressure, and suggests a way in which repeated episodes of prolpase and urethral traction by shearing forces exerted by the vagina on the urethra may contribute to the development of intrinsic sphincteric deficiency.

Computer Systems↗

Changing the pathophysiology of solid tumours: the potential of TNF and other vasoactive agents.

Solid tumour therapy with chemotherapeutic drugs is hampered by a number of factors resulting in poor results and failure of initially promising drugs. From the application of Tumour Necrosis Factor alpha in the melphalan-based Isolated Limb perfusion some lessons could be learned. Most importantly, combination of treatment approaches, certainly when multiple targets are involved, increases the effectiveness of the therapy. Clinical outcome may improve dramatically when the tumour pathophysiology is changed in such a way that co-administered chemotherapeutics are more active or are capable of reaching the tumour cells better. Here some of the methodologies and drug combinations which improve solid tumour therapy through acting on the tumour pathophysiology are discussed.

Antineoplastic Agents↗

Neuropeptides involved in the pathophysiology of schizophrenia and major depression.

The present review summarizes the findings on the role of neuropeptides in the pathophysiology of schizophrenia and major depression. Several neuropeptides as vasopressin and endorphins in particular, beta-endorphin and gamma-type endorphins, cholecystokinin (CCK), neurotensin, somatostatin and Neuropeptide Y have been implicated in schizophrenia. During the last decade, however, few attempts to explore the significance of most of these and other neuropeptides in the pathophysiology of the disease or their therapeutic potential are found in the literature. An exception is neurotensin, which exerts neuroleptic-like effects in animal studies, while CSF, brain and blood studies are inconclusive. Things are different in major depression. Here much attention is paid to the endocrine abnormalities found in this disorder in particular the increased activity of the hypothalamic-pituitary-adrenal (HPA) axis. Neuropeptides as corticotropin-releasing hormone (CRH), vasopressin and corticosteroids are implicated in the symptomatology of this disorder. As a consequence much work is going on investigating the influence of CRH and corticosteroid antagonists or inhibitors of the synthesis of corticosteroids as potential therapeutic agents. This review emphasizes the role of vasopressin in the increased activity of the HPA axis in major depression and suggests exploration of the influence of the now available non-peptidergic vasopressin orally active V1 antagonists.

Journal Article↗

Pathophysiological classification of human spinal cord ischemia.

Diagnosis of myelopathies of vascular origin is difficult and they are probably underdiagnosed at this time because of the lack of diagnostic tools. A recent report of a 58 year old patient who developed ASAS after an episode of cardiac arrest pointed out the importance of MRI and somatosensory evoked potentials (SEP) to support the diagnosis. MRI with T2 weighted imaging demonstrated diffuse signal abnormalities in both gray matter and surrounding white matter below T7. Furthermore, SEP latencies showed a delay between T6 and T7. Therefore, new technologies including MRI and SEP may improve the diagnosis of spinal cord ischemic injuries. A brief discussion of the normal blood supply of the human spinal cord is presented in this review followed by new, pathophysiologically based classifications of the clinical syndromes of vascular myelopathies. A complete description of the clinical syndromes related to vascular myelopathies is included. Vascular myelopathies were divided into acute and chronic syndromes depending on the time at which the pathophysiological events take place. Subsequently, the two major groups of vascular myelopathies were divided depending on the type of vascular damage, e.g., arterial, venous and/or mixed origin. Posttraumatic spinal cord ischemia is included in the present classification because it is generally considered to be a significant factor contributing to secondary damage following blunt trauma. Since several new diagnostic techniques are now available to characterize the pathology of spinal cord injury, physicians involved in the diagnosis and treatment of vascular myelopathies may find the new classification useful in correlating clinical presentation with subjacent pathology. Identification of the correct pathology should result in more accurate treatment approaches.

Arteries↗

A pathophysiological approach to metabolic syndrome using factor analysis in an adult Romanian population.

The aim of the study was to examine the role of insulin resistance in etiopathogenesis of metabolic syndrome in an adult Romanian population using exploratory factor analysis. We analyzed 228 non-diabetic subjects randomized in respect to the age and sex distribution of the general population. For each patient, age, sex, body mass index (BMI), systolic and diastolic blood pressure (SBP, DBP), HDL-cholesterol (HDL), plasma triglycerides (TG), fasting plasma glucose (FPG) and fasting insulin were obtained. Factor analysis was performed using principal component analysis, with Varimax rotation of the major determinants of metabolic syndrome. Mean age was 48.9 +/- 12.7 years; 107 (46.9%) were men and 121 (53.1%) women. We found three major factors, which are correlated with metabolic syndrome and may explain its variance. Factor 1 comprises SBP and DBP in men and SBP, DBP and BMI in women. Factor 2 comprises BMI, HDL, TG and FPG in men and BMI, TG and FPG in women. Factor 3 comprises fasting insulin in men and fasting insulin, TG and HDL in women. The finding of more than one factor suggests that insulin resistance is not the only pathophysiological mechanism involved. These factors appear to work independently of each other in men, but they intersect in women, suggesting that the pathophysiology of metabolic syndrome may be different in women compared with men.

Adult↗

Results from clinical trials on ST-elevation myocardial infarction in a historic perspective with some pathophysiological aspects.

OBJECTIVE: Since the publication of the large trials on streptokinase and aspirin improving mortality related to an acute ST-elevation myocardial infarction (STEMI) there has been numerous studies on improving treatment results with new fibrinolytics, adjuvant heparin therapy and primary percutaneous intervention (PCI). The aim of the present overview is, in a historic perspective, to link some of the pathophysiology of mechanisms related to plaque rupture and following thrombosis to the effects of drug combinations and PCI observed in major clinical trials conducted in patients with STEMI. DESIGN: The overview comprises short analyses of the initial streptokinase trials (GISSI-1 and ISIS-2), the comparisons between streptokinase and tissue plasminogen activator (rt-PA) and the role of adjuvant heparin treatment (GISSI-2, ISIS-3, GUSTO I). Also included is the comparison between the new bolus-teplases and traditional, accelerated infusion of rt-PA (GUSTO III and ASSENT-2) and between unfractionated heparin (UFH) and low molecular weight heparin (LWMH) given in addition to tenecteplase (ASSENT-3). The pathophysiology of the antiplatelet and antithrombin effects is described, in order to elucidate the treatment differences observed in the trials. In addition, the role of primary PCI is discussed in view of the results in a recent meta-analysis of controlled comparisons with fibrinolytic therapy. RESULTS: Based upon these trials it seems that the optimal thrombolytic treatment is a combination of a bolus-teplase (tenecteplae) and LMWH given on top of aspirin. Primary PCI may be the most optimal treatment, provided given early following STEMI (<1 h), but whether PCI is the best alternative for all patients with STEMI is still a matter of debate. CONCLUSION: During the last 15 years the optimal antithrombotic treatment of STEMI has developed from a combination of streptokinase and aspirin to the new bolus-teplases combined with LMWH and aspirin. The use of primary PCI may be a better alternative than fibrinolytic therapy, but such a statement needs confirmation in a large comparison between PCI and a quick infusion of modern fibrinolytic agents.

Angioplasty, Balloon, Coronary↗