Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “pathophysiology”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources

Left ventricular diastolic function after anthracycline chemotherapy in childhood: relation with systolic function, symptoms, and pathophysiology.

OBJECTIVES: To examine left ventricular (LV) diastolic function in patients previously treated with anthracycline drugs for childhood malignancy. To consider clinical relevance, relations with systolic dysfunction, and the pathophysiology of anthracycline cardiotoxicity. DESIGN: Cross sectional echocardiographic study of LV function. SETTING: Supraregional centre for paediatric cardiology, principal centre for the treatment of childhood malignancy in southwest England. PATIENTS: 226 of 236 patients surviving between 6.5 months and 17 (median 5.3) years from initial anthracycline treatment for childhood malignancy attended for clinical and echocardiographic examination. Cumulative anthracycline doses were between 50 and 750 (median 300) mg/m2. 22 patients had also received cardiac irradiation. METHODS: Detailed assessment of transmitral diastolic pulsed wave Doppler flow patterns along with LV dimensions and systolic function measured by M mode echocardiography. MAIN OUTCOME MEASURES: Peak early (E) and atrial (A) phase filling velocities and EA ratio, time and acceleration and deceleration to and from peak E velocity, velocity integrals and ratio, isovolumic relaxation time (IVRT), and heart rate were measured. Results were examined in relation to LV cavity and posterior wall dimensions and shortening fraction (SF), and compared with paired control data matched for body surface area. RESULTS: Eleven (5%) patients had abnormal effort tolerance. Fifty one (23%) had SF < 30% and SF was inversely correlated with cumulative dose and time from treatment. The relative risk of symptomatic cardiac failure was greatly increased by prior irradiation; > 60% of irradiated patients who received > 400 mg/m2 of anthracycline were symptomatic. Early diastolic filling was relatively normal or enhanced at low anthracycline doses or when SF was preserved, with a shorter IVRT and increased atrial phase filling. Early filling was reduced at higher doses or with reduced SF, with longer IVRT and a further increase in atrial phase filling. A more "restrictive" pattern of diastolic filling (with high E and low A velocities) was seen in some patients, particularly after cardiac irradiation. CONCLUSIONS: Significant abnormalities of diastolic function are associated with anthracycline induced cardiac damage. These are not linearly related to anthracycline dose but appear to reflect the underlying myocardial pathophysiology associated with anthracycline toxicity, which is not demonstrated by the standard M mode echocardiogram. Although the overall clinical significance of such diastolic dysfunction is uncertain, some individual abnormalities may have significant management and therapeutic implications.

Adolescent↗

Acute intraoperative brain herniation during elective neurosurgery: pathophysiology and management considerations.

OBJECTIVES: To describe operative procedures, pathophysiological events, management strategies, and clinical outcomes after acute intraoperative brain herniation during elective neurosurgery. METHODS: Review of clinical diagnoses, operative events, postoperative CT findings, intracranial pressure, and arterial blood pressure changes and outcomes in a series of patients in whom elective neurosurgery had to be abandoned because of severe brain herniation. RESULTS: Acute intraoperative brain herniation occurred in seven patients. In each patient subarachnoid or intraventricular haemorrhage preceded the brain herniation. The haemorrhage occurred after intraoperative aneurysm rupture either before arachnoidal dissection (three) or during clip placement (one); after resection of 70% of a recurrent hemispheric astroblastoma; after resection of a pineal tumour; and after a stereotactic biopsy of an AIDS lesion. In all patients the procedure was abandoned because of loss of access to the intracranial operating site, medical measures to control intracranial pressure undertaken (intravenous thiopentone), an intraventricular catheter or Camino intracranial pressure monitor inserted, and CT performed immediately after scalp closure. The patients were transferred to an intensive care unit for elective ventilation and multimodality physiological monitoring. Using this strategy all patients recovered from the acute ictus and no patient had intracranial pressure > 35 mm Hg. Although one patient with an aneurysm rebled and died three days later the other six patients did well considering the dramatic and apparently catastrophic nature of the open brain herniation. CONCLUSIONS: There are fundamental differences in the pathophysiological mechanisms, neuroradiological findings, and outcomes between open brain herniation occurring in post-traumatic and elective neurosurgical patients. The surprisingly good outcomes in this series may have occurred because the intraoperative brain herniation was secondary to extra-axial subarachnoid or intraventricular haemorrhage rather than intraparenchymal haemorrhage or acute brain oedema. Expeditious abandonment of the procedure and closure of the cranium may also have contributed to the often very satisfactory clinical outcome.

Adult↗

COPD exacerbations . 3: Pathophysiology.

Exacerbations of chronic obstructive pulmonary disease (COPD) are associated with increased morbidity and mortality. The effective management of COPD exacerbations awaits a better understanding of the underlying pathophysiological mechanisms that shape its clinical expression. The clinical presentation of exacerbations of COPD is highly variable and ranges from episodic symptomatic deterioration that is poorly responsive to usual treatment, to devastating life threatening events. This underscores the heterogeneous physiological mechanisms of this complex disease, as well as the variation in response to the provoking stimulus. The derangements in ventilatory mechanics, muscle function, and gas exchange that characterise severe COPD exacerbations with respiratory failure are now well understood. Critical expiratory flow limitation and the consequent dynamic lung hyperinflation appear to be the proximate deleterious events. Similar basic mechanisms probably explain the clinical manifestations of less severe exacerbations of COPD, but this needs further scientific validation. In this review we summarise what we have learned about the natural history of COPD exacerbations from clinical studies that have incorporated physiological measurements. We discuss the pathophysiology of clinically stable COPD and examine the impact of acutely increased expiratory flow limitation on the compromised respiratory system. Finally, we review the chain of physiological events that leads to acute ventilatory insufficiency in severe exacerbations.

Acute Disease↗

Modulation and roles of the endothelins in the pathophysiology of pulmonary embolism.

Recent research on the endothelins (ETs) and their pathways in acute pulmonary embolism (APE) has led to significant advances in the understanding of this disease. ETs are potent vasoconstrictors and bronchoconstrictors found abundantly in the lung and can be released by stimuli such as endothelial injury, hypoxia, or thrombin, a key product in the coagulation cascade. Many studies using different approaches and methods of inducing pulmonary embolization, both in vitro and in vivo in various species, have mostly shown that ETs play an important role in the pathophysiology of APE. These results were obtained by comparing the hemodynamic data in the presence or absence of various ETs inhibitors, but also by assessing the modulation of the ET-related elements of this system by molecular, cell biology, and pharmacological methods. Based on the current understanding, a mechanism involving the ET pathway in the pathophysiology of APE is proposed for the reader's considerations. We postulate that ETs are primary mediators in APE based on the following: (i) their source from pulmonary endothelial cells where the primary injury takes place; (ii) their direct vasconstrictive, bronchoconstrictive, and promitogenic effects via distinct ET receptors; and (iii) their indirect effects associated with the secondary release of thromboxane and other mediators, which are released from inflammatory cells and platelets, which together can potentiate the overall hemodynamic response, most specifically the pulmonary vascular bed. Such combined effects of ETs on bronchomotor and vasomotor tone in the lung can adversely affect ventilation perfusion matching and lead to severe hypoxemia without causing significant changes in the chest X-ray of these patients. Thus, we may consider ET inhibitors as future current therapeutic agents in patients with PE.

Animals↗

Pathophysiology and treatment of sleep apnea.

The sleep apnea syndromes have attracted the interest of physicians and scientists in many different disciplines because the disorders involve the physiology of sleep, the control of respiration, the function of the upper airway, and the clinical sequelae upon cardiac, pulmonary, and psychological function. Over the eight years since this subject was last reviewed here (1), the pathophysiology of obstructive sleep apnea has become better understood. A variety of new treatments are now available. However, our clinical knowledge of the syndrome and its natural history have changed little. The high prevalence of these syndromes and related disorders such as snoring is only beginning to be apparent. This chapter reviews current understanding of these syndromes, with particular emphasis on recent advances, and highlights questions for future investigation. First, we consider normal upper airway function and the control of breathing during sleep. Then, we apply this information to a consideration of the pathophysiology, clinical features, and treatment of sleep apnea syndromes.

Airway Resistance↗

The clinical pathophysiology of sickle cell disease.

Polymerization of deoxyhemoglobin S within sickle erythrocytes is of cardinal importance to each of the clinical complications of sickle cell anemia. Sickle gene expression, however, is modulated by a number of pathophysiological mechanisms that generate vast clinical diversity among sickle cell patients. These processes include genotypic variations, modifications of polymerization, abnormal erythrocyte hydration, membrane defects, and rheologic factors. In many cases it is possible to relate specific pathophysiological mechanisms to particular disease features or to possibilities for therapeutic intervention.

Anemia, Sickle Cell↗

Dyspnea: physiological and pathophysiological mechanisms.

Dyspnea, the sensation of feeling breathless, is a symptom experienced under conditions in which there is an inordinately high ventilatory demand relative to the ability to breathe. Its major physical sign is tachypnea. New developments in monitoring ventilation during exercise have improved our ability to evaluate the symptom of dyspnea and to understand pathophysiological mechanisms contributing to the symptom. We briefly describe the range of mechanisms that determine exercise ventilation and their possible relationship to dyspnea. Questionnaires and psychophysical testing have been used to quantify dyspnea, but there is variability in dyspnea grade from these methods. Dyspnea-producing stimuli and the mechanisms by which they act are reviewed. Disorders producing dyspnea and the pathophysiological mechanisms underlying each are discussed. Perception of dyspnea is obviously through the central nervous system, where dyspnea-producing stimuli are integrated. The specific integration site is probably in the region of the brain stem, since occasional patients with brain stem lesions do not experience dyspnea despite the presence of a number of dyspnea-producing stimuli.

Anemia↗

Biology of gastroesophageal reflux disease: pathophysiology relating to medical and surgical treatment.

This chapter reviews the biology of gastroesophageal reflux disease, relating pathophysiology to medical and surgical therapy. Various definitions of the disease are presented and workable criteria are developed to identify patients with the disease. The central importance of the lower esophageal high-pressure zone as a barrier to reflux is emphasized, along with an analysis of its biomechanical alteration in disease. The composition of the refluxed gastric juice is characterized in regard to its potential for mucosal injury. Evidence is provided that cardiac-type mucosa is an acquired sequel to acid-induced squamous mucosal injury in the terminal esophagus. A hypothesis regarding the process of intestinalization of cardiac-type mucosa to form Barrett's esophagus is presented. An integrated concept of the pathophysiology of gastroesophageal reflux disease is constructed. Practical concepts regarding the treatment of gastroesophageal reflux disease are developed, based on a review of studies on the natural history of the disease and the long-term outcome of therapy.

Barrett Esophagus↗

Pathophysiological basis of vulnerability to drug abuse: role of an interaction between stress, glucocorticoids, and dopaminergic neurons.

Research on drug abuse has recently focused on understanding the vulnerability to develop addiction that is present in certain individuals. These investigations suggest that addiction results from an interaction between drugs and specific individual substrates. Differences in the propensity to develop drug intake can be demonstrated in animals with equal access to drugs under stable laboratory conditions and can be predicted by drug-independent behaviors. Stress, corticosterone, and mesencephalic dopaminergic neurons seem to be organized in a pathophysiological chain determining such a vulnerability. An increased corticosterone secretion, or a higher sensitivity to the effects of this hormone, either naturally present in certain individuals or induced by stress in others, increases the vulnerability to develop drug intake, via an enhancement of the activity of mesencephalic dopaminergic neurons. These findings suggest that addiction therapies should counteract the biological peculiarity that leads some individuals to respond in a pathophysiological way to drugs.

Animals↗

Pathophysiology of endothelin in the cardiovascular system.

In this article, we review the basic pharmacological and biochemical features of endothelin and the pathophysiological roles of endothelin in cardiovascular diseases. Development of receptor antagonists has accelerated the pace of investigations into the pathophysiological roles of endogenous endothelin-1 in various diseases, e.g. chronic heart failure, renal diseases, hypertension, cerebral vasospasm, and pulmonary hypertension. In chronic heart failure, the expression of endothelin-1 and its receptors in cardiomyocytes is increased, and treatment with an endothelin receptor antagonist improves survival and cardiac function. Endothelin receptor antagonists also improve other cardiovascular diseases. These results suggest that the interference with endothelin pathway either by receptor blockade or by inhibition of endothelin converting enzyme may provide novel therapeutic drugs strategies for multiple disease states.

Animals↗

Cardiac-specific blockade of NF-kappaB in cardiac pathophysiology: differences between acute and chronic stimuli in vivo.

The role of NF-kappaB in cardiac physiology and pathophysiology has been difficult to delineate due to the inability to specifically block NF-kappaB signaling in the heart. Cardiac-specific transgenic models have recently been developed that repress NF-kappaB activation by preventing phosphorylation at specific serine residues of the inhibitory kappaB (IkappaB) protein isoform IkappaBalpha. However, these models are unable to completely block NF-kappaB because of a second signaling pathway that regulates NF-kappaB function via Tyr42 phosphorylation of IkappaBalpha. We report the development of transgenic (3M) mouse lines that express the mutant IkappaBalpha(S32A,S36A,Y42F) in a cardiac-specific manner. NF-kappaB activation in cardiomyopathic TNF-1.6 mice is completely blocked by the 3M transgene but only partially blocked (70-80%) by the previously described double-mutant 2M [IkappaBalpha(S32A,S36A)] transgene, which demonstrates the action of two proximal pathways for NF-kappaB activation in TNF-alpha-induced cardiomyopathy. In contrast, after acute stimuli including administration of TNF-alpha and ischemia-reperfusion (I/R), NF-kappaB activation is blocked in both 2M and 3M transgenic mice. This result suggests that phosphorylation of the regulatory Ser32 and Ser36 predominantly mediates NF-kappaB activation in these situations. We show that infarct size after I/R is reduced by 70% in 3M transgenic mice, which conclusively demonstrates that NF-kappaB is involved in I/R injury. In summary, we have engineered novel transgenic mice that allow us to distinguish two major proximal pathways for NF-kappaB activation. Our results demonstrate that the serine and tyrosine phosphorylation pathways are differentially activated during different pathophysiological processes (cardiomyopathy and I/R injury) and that NF-kappaB contributes to infarct development after I/R.

Animals↗

Contribution of T cell subsets to the pathophysiology of Pneumocystis-related immunorestitution disease.

Immune-mediated lung injury is an important component of Pneumocystis pneumonia (PcP)-related immunorestitution disease (IRD). However, the individual contribution of CD4(+) and CD8(+) T cells to the pathophysiology of IRD remains undetermined. Therefore, IRD was modeled in severe combined immunodeficient mice, and specific T cell depletion was used to determine how T cell subsets interact to affect the nature and severity of disease. CD4(+) cells were more abundant than CD8(+) cells during the acute stage of IRD that coincided with impaired pulmonary physiology and organism clearance. Conversely, CD8(+) cells were more abundant during the resolution phase following P. carinii clearance. Depletion of CD4(+) T cells protected mice from the acute pathophysiology of IRD. However, these mice could not clear the infection and developed severe PcP at later time points when a pathological CD8(+) T cell response was observed. In contrast, mice depleted of CD8(+) T cells efficiently cleared the infection but developed more severe disease, an increased frequency of IFN-gamma-producing CD4(+) cells, and a prolonged CD4(+) T cell response than mice with both CD4(+) and CD8(+) cells. These data suggest that CD4(+) T cells mediate the acute respiratory disease associated with IRD. In contrast, CD8(+) T cells contributed to neither lung injury nor organism clearance when CD4(+) cells were present, but instead served to modulate CD4 function. In the absence of CD4(+) cells, CD8(+) T cells produced a nonprotective, pathological immune response. These data suggest that the interplay of CD4(+) and CD8(+) T cells affects the ultimate outcome of PcP-related IRD.

Animals↗

Physiological and pathophysiological roles of oxygen radicals in the renal microvasculature.

The renal microvasculature is an important component in the regulation of kidney function. Recent studies suggest that oxygen radicals can contribute to the modulation of renal cortical and medullary microvascular function under normal conditions as well as in pathophysiological conditions such as diabetes mellitus and hypertension. This review focuses on studies that indicate oxygen radicals can cause renal vasoconstriction, mediate the vasoconstriction of other agonists, and modulate nitric oxide-dependent actions in the normal kidney. Hypertension and diabetes mellitus are associated with oxidative stress. Recent investigations suggest that oxygen radicals may contribute to the enhanced renal vascular tone, increased sensitivity to vasoconstrictors, impaired endothelium-dependent vasodilation, and enhanced tubuloglomerular feedback found in these pathophysiological conditions.

Animals↗

BNP: pathophysiological and potential therapeutic roles in acute congestive heart failure.

Controversy persists regarding the acute responsiveness of atrial (ANP) and brain (BNP) natriuretic peptides in pathophysiological conditions such as acute heart failure (AHF). This study was designed to test the hypothesis that AHF is characterized by selective activation of ANP, but not BNP. We also hypothesized that BNP replacement in AHF would reduce cardiac filling pressures, increase sodium excretion, and inhibit circulating renin. Two groups of anesthetized dogs underwent rapid left ventricular pacing to induce AHF. Group 1 (n = 7) served as control and group 2 (n = 7) received canine BNP (10 ng x kg(-1) x min(-1)). Cardiorenal parameters, circulating natriuretic peptides, 3',5'-cyclic guanosine monophosphate (cGMP), and plasma renin activity (PRA) were determined at baseline and during AHF in both groups. AHF was characterized by reductions in cardiac output (2.3 +/- 0.2 vs. 3.7 +/- 0.3 l/min, P < 0.05), pulmonary capillary wedge pressure (PCWP; 11.7 +/- 0.8 vs. 5.1 +/- 0.3 mmHg, P < 0.05), and selective activation of ANP (250 +/- 51 vs. 39 +/- 13 pg/ml, P < 0.05), with no increase in circulating BNP (49 +/- 15 vs. 60 +/- 16 pg/ml, P = not significant). Compared with control, exogenous supplemental BNP in AHF resulted in marked increases in circulating cGMP (65 +/- 6 vs. 18 +/- 5 pg/ml, P < 0.05), with reductions in PCWP (9.1 +/- 0.9 vs. 12.9 +/- 1.1 mmHg, P < 0.05) and increased urinary sodium excretion (120 +/- 36.8 vs. 24 +/- 6.3 microeq/min, P < 0.05) via reductions in distal tubular sodium reabsorption (94.3 +/- 1.8 vs. 98.0 +/- 0.4%, P < 0.05). Exogenous BNP prevented the increase in PRA that occurred in the control group. We conclude that AHF is characterized by a failure to increase circulating BNP underscoring differential physiological and pathophysiological roles for ANP and BNP in states of immediate cardiac overload. These studies also support a potential role for BNP in the therapeutics of AHF.

Acute Disease↗

H+-K+-ATPases: regulation and role in pathophysiological states.

Molecular cloning experiments have identified the existence of two H+-K+-ATPases (HKAs), colonic and gastric. Recent functional and molecular studies indicate the presence of both transporters in the kidney, which are presumed to mediate the exchange of intracellular H+ for extracellular K+. On the basis of these studies, a picture is evolving that indicates differential regulation of HKAs at the molecular level in acid-base and electrolyte disorders. Of the two transporters, gastric HKA is expressed constitutively along the length of the collecting duct and is responsible for H+ secretion and K+ reabsorption under normal conditions and may be stimulated with acid-base perturbations and/or K+ depletion. This regulation may be species specific. To date there are no data to indicate that the colonic HKA (HKAc) plays a role in H+ secretion or K+ reabsorption under normal conditions. However, HKAc shows adaptive regulation in pathophysiological conditions such as K+ depletion, NaCl deficiency, and proximal renal tubular acidosis, suggesting an important role for this exchanger in potassium, HCO-3, and sodium (or chloride) reabsorption in disease states. The purpose of this review is to summarize recent functional and molecular studies on the regulation of HKAs in physiological and pathophysiological states. Possible signals responsible for regulation of HKAs in these conditions will be discussed. Furthermore, the role of these transporters in acid-base and electrolyte homeostasis will be evaluated in the context of genetically altered animals deficient in HKAc.

Acidosis↗

The role of free radicals in the pathophysiology of muscular dystrophy.

Null mutation of any one of several members of the dystrophin protein complex can cause progressive, and possibly fatal, muscle wasting. Although these muscular dystrophies arise from mutation of a single gene that is expressed primarily in muscle, the resulting pathology is complex and multisystemic, which shows a broader disruption of homeostasis than would be predicted by deletion of a single-gene product. Before the identification of the deficient proteins that underlie muscular dystrophies, such as Duchenne muscular dystrophy (DMD), oxidative stress was proposed as a major cause of the disease. Now, current knowledge supports the likelihood that interactions between the primary genetic defect and disruptions in the normal production of free radicals contribute to the pathophysiology of muscular dystrophies. In this review, we focus on the pathophysiology that results from dystrophin deficiency in humans with DMD and the mdx mouse model of DMD. Current evidence indicates three general routes through which free radical production can be disrupted in dystrophin deficiency to contribute to the ensuing pathology. First, constitutive differences in free radical production can disrupt signaling processes in muscle and other tissues and thereby exacerbate pathology. Second, tissue responses to the presence of pathology can cause a shift in free radical production that can promote cellular injury and dysfunction. Finally, behavioral differences in the affected individual can cause further changes in the production and stoichiometry of free radicals and thereby contribute to disease. Unfortunately, the complexity of the free radical-mediated processes that are perturbed in complex pathologies such as DMD will make it difficult to develop therapeutic approaches founded on systemic administration of antioxidants. More mechanistic knowledge of the specific disruptions of free radicals that underlie major features of muscular dystrophy is needed to develop more targeted and successful therapeutic approaches.

Animals↗

Molecular physiology and pathophysiology of electroneutral cation-chloride cotransporters.

Electroneutral cation-Cl(-) cotransporters compose a family of solute carriers in which cation (Na(+) or K(+)) movement through the plasma membrane is always accompanied by Cl(-) in a 1:1 stoichiometry. Seven well-characterized members include one gene encoding the thiazide-sensitive Na(+)-Cl(-) cotransporter, two genes encoding loop diuretic-sensitive Na(+)-K(+)-2Cl(-) cotransporters, and four genes encoding K(+)-Cl(-) cotransporters. These membrane proteins are involved in several physiological activities including transepithelial ion absorption and secretion, cell volume regulation, and setting intracellular Cl(-) concentration below or above its electrochemical potential equilibrium. In addition, members of this family play an important role in cardiovascular and neuronal pharmacology and pathophysiology. Some of these cotransporters serve as targets for loop diuretics and thiazide-type diuretics, which are among the most commonly prescribed drugs in the world, and inactivating mutations of three members of the family cause inherited diseases such as Bartter's, Gitelman's, and Anderman's diseases. Major advances have been made in the past decade as consequences of molecular identification of all members in this family. This work is a comprehensive review of the knowledge that has evolved in this area and includes molecular biology of each gene, functional properties of identified cotransporters, structure-function relationships, and physiological and pathophysiological roles of each cotransporter.

Animals↗

Pathophysiological effects of vascular endothelial growth factor receptor-2-blocking antibody plus fractionated radiotherapy on murine mammary tumors.

Although clinical trials of antiangiogenic strategies have been disappointing when administered as single agents, such approaches can play an important role in cancer treatment when combined with conventional therapies. Previous studies have shown that DC101, an antiangiogenic monoclonal antibody against vascular endothelial growth factor receptor-2, can produce significant growth inhibition in spontaneous and transplanted tumors but can also induce substantial hypoxia. Because DC101 appears to potentiate radiotherapy in some tumors, the present studies were undertaken to characterize pathophysiological changes following combined therapy and to determine whether radioresponse is enhanced despite the induction of hypoxia. MCa-4 and MCa-35 mammary carcinomas were treated with: (a) DC101; (b) 5 x 6 Gy radiation fractions; or (c) the combination. Image analysis of frozen tumor sections was used to quantitate: (a) hypoxia; (b) spacing of total and perfused blood vessels; and (c) endothelial and tumor cell apoptosis. For MCa-4, combination treatment schedules produced significant and prolonged delays in tumor growth, whereas single-modality treatments had minor effects. For MCa-35, radiation or the combination led to equivalent growth inhibition. In all tumors, hypoxia increased markedly after either radiation or DC101 alone. Although combination therapy produced no immediate pathophysiological changes, hypoxia ultimately increased after cessation of therapy. Preferential increases in endothelial apoptosis following combination treatment suggest that in addition to blocking tumor angiogenesis, DC101 enhances radiotherapy by specifically sensitizing endothelial cells, leading to degeneration of newly formed blood vessels.

Animals↗