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Query: UMLS:C0264733 (ventricular dilatation)
 2,163 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On the basis of the laws of Pascal and Laplace, it is shown that the ventricular dilatation in acquired hydrocephalus is due to a primary increase in the intraventricular pressure (IVP), and that a new steady state can be reached, whether the IVP is increased or normal. The pressure increase is due to a disproportion between the production and reabsorption of cerebrospinal fluid (CSF). As water and salts pass freely across the ependyma and the choroid plexus in hydrocephalus, the pressure increase is caused by an increased protein concentration in the ventricular CSF, leading to increased fluid contents according to the Gibbs-Donnan equilibrium. During the ventricular dilatation, the ependyma is destroyed, and the protein molecules penetrate into the subependymal part of the white matter. This results in a reduction in the colloid osmotic pressure of the ventricular CSF, and a new steady state can be reached, with a normal protein concentration in an increased volume. The attendant microscopic changes in the ventricular wall were demonstrated in a patient with acquired hydrocephalus, and the observations made were in conformity with the results of a number of animal experiments. The symptomatology of acquired hydrocephalus is in agreement with a primary affection of the axons running in the juxtaventricular part of the white matter.
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PMID:Acquired hydrocephalus. III. A pathophysiological study correlated with neuropathological findings and clinical manifestations. 47 7

32 cases of traumatic subdural hygroma (TSH) in adults with surgical treatment were retrospectively investigated by means by clinical features and CT findings. The cases consisted of 29 males and 3 females, aged 41 to 87 years (mean 69). Preparative CT scan of all cases revealed low density area and crescent shape in frontotemporal or frontoparietal subdural space. Half of the cases had bilateral lesions. At operation of TSH, color of subdural fluid collections was more water clear or xanthochromic than bloody. As a results, 22 out of 32 cases (69%) in TSH improved with surgical treatment. Many of effective cases of surgical treatment in TSH had short interval from trauma to operation and light disturbance of consciousness before operation. However, the other intracranial damage will also affect the clinical outcome of TSH, because the majority of cases in this study was accompanied by an intracranial damage including cerebral contusion, subarachnoid hemorrhage or intracranial hemorrhage. Nevertheless, surgical management for TSH was so effective that the operation should be undergone sooner interval from trauma, simultaneously considering the another intracranial lesions except TSH. But then, we experienced 7 cases (22%) of ventricular dilatation and 5 cases (16%) of chronic subdural hematoma in postoperative follow up CT scans. In 5 cases among the former, ventriculoperitonial shunt was done, and in 3 cases among the latter, burr hole evacuation was performed. Therefore, the postoperative course of TSH should require careful observation by CT scan and so on.
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PMID:[Surgical outcome of 32 cases in traumatic subdural hygroma]. 129 33

We describe a new experimental model of fetal hydrocephalus in the lamb. 14 sheep were operated on at 100-120 days gestation for the insertion of a catheter into the fetal aqueduct of Sylvius to block cerebrospinal fluid (CSF) flow. After the operation the intracranial pressure (ICP) was measured daily from the distal end of the catheter. The progress of ventricular dilatation was recorded by ultrasound. At ICP 100 mm/H2O the animals were killed for postmortem examination of the fetuses. Neuropathological examination showed massive dilatation of the ventricles. The ependymal cells appeared to be flat and the cellular lining disrupted. Growth of pseudocysts, cellular stratification and proliferation of the paraventricular germinal cells were observed also. With our new experimental model we were able to control the rise in ICP and correlate the evolution of the anatomical damage with the duration of high ICP and with the gestational age at which it began. Our model can also be used at early stages of gestation for reversing the development of hydrocephalus. It might therefore provide information on the suitability of fetal hydrocephalus surgery.
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PMID:Congenital hydrocephalus: a new experimental model with histopathological study. 208 80

Fetal cardiac changes due to ductal constriction by maternal ingestion of nonsteroidal anti-inflammatory drugs were studied morphologically in near-term rats as an animal model, and results were compared with values of control 1 (C1, twenty-first day) and control 2 (C2, twenty-second day). The fetal ductus was constricted (-70%) (p less than 0.05) by maternal administration of 10 mg/kg indomethacin. Dilatation of the right ventricle and evidence of congestive heart failure including increased pericardial effusion (+200%) (p less than 0.05) and an increase in water content in the abdominal wall were present at 1, 4, and 8 hours after drug administration. At 24 hours after drug administration, concentric right ventricular hypertrophy was shown by a diminished right ventricular cavity (-36% vs. C2) (p less than 0.05), increased right ventricular wall thickness (+70% vs. C2) (p less than 0.05), and increased right ventricular mass (+31% vs. C1) (p less than 0.05). Left ventricular dilatation was indicated by an increased cavity volume (+87% vs. C2) (p less than 0.05) and increased muscle mass (+29% vs. C1 [p less than 0.05] or +9% vs. C2 [p greater than 0.05]). Both the wet and dry weights of the ventricles were increased. In conclusion, fetal ductal constriction caused right ventricular hypertrophy, diminished right ventricular cavity, and left ventricular dilatation and hypertrophy at 24 hours after drug administration in rats after initial congestive failure.
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PMID:Right ventricular concentric hypertrophy and left ventricular dilatation by ductal constriction in fetal rats. 252 91

The age distributions of communicating hydrocephalus (CH), pseudotumour cerebri (PC) slit-ventricle syndrome (SVS), and chronic subdural haematomas (CSH) were reviewed in the medical literature. An age-related incidence was found: CH and CSH predominated in neonates less than 2 years and adults older than 55 years, while PC and SVS occurred mainly in older children and young adults. The latter two patient groups seem to show a greater resistance to ventricular dilatation in the presence of decreased CSF absorption. This may be related to larger volume and state of maturity of the cerebrum. On the other hand, neonates and the elderly more readily develop enlarged ventricles, in association with impairment of CSF absorption, or subdural fluid collections. Factors including status of cranial sutures, cerebral atrophy, cerebral water content, degree of cerebral myelination, and glial cell composition, may contribute to the age-related incidence of the four disorders investigated. Similarly, the development of ventriculomegaly may depend upon cerebral elastic properties besides the pri mary disturbance of CSF dynamics. The authors postulate that the size of cerebral ventricles in disorders of the cerebrospinal fluid (CSF) absorption is related to the elastic properties and volume of the brain. Furthermore, cerebral volume and elastic properties may also contribute to the age distribution of chronic subdural haematomas (CSH).
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PMID:Age-dependent changes of cerebral ventricular size. Part I: Review of intracranial fluid collections. 265 72

Cerebral blood flow and metabolism were studied in experimental hydrocephalus which was produced by intracisternal injection of kaolin in cats, rabbits and rats. Measurements were carried out in varied stages of hydrocephalus. Local cerebral blood flow (l-CBF) was measured by the hydrogen clearance method. Assessment of cerebral metabolism was made biochemically in the brain tissues of various regions, including water content, Na, K, lactate, pyruvate, lipids, ATP, cyclic AMP, catecholamines and monoamine metabolites. Blood flow studies were performed in the cerebral cortex, periventricular white matter, thalamus and midbrain reticular formation in hydrocephalic cats. In all of these regions, l-CBF decreased to about half of the control in both acute and chronic stages of hydrocephalus. CO2 reactivity to CBF was impaired only in the acute stage, while autoregulation of CBF was preserved in the hydrocephalic brain. Water content of the brain tissue increased temporarily only within the periventricular white matter of hydrocephalic rabbits concomitant with increase in Na and decrease in K. Transient increase in the lactate and lactate/pyruvate ratios was also observed in the frontal lobe tissue. In hydrocephalic rats, decrease in phospholipids and cholesterol was observed parallel with the degree of ventricular dilatation. ATP and cyclic AMP decreased biphasically in both acute and chronic stages. On the other hand, increase in concentrations of norepinephrine, dopamine, homovanillic acid, and 5-hydroxyindoleacetic acid became evident in the chronic stage of hydrocephalus. From the above results, it is concluded that the hydrocephalic brain sustained considerable disturbance of metabolism in all modalities in association with decreased blood flow, which is sufficient to explain the clinical symptoms of hydrocephalus.
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PMID:Cerebral blood flow and metabolism in experimental hydrocephalus. 287 11

In previous studies swimming training (ST) of spontaneously hypertensive rats (SHR) at 36 degrees water temperature (WT) led to a decrease in blood pressure (BP). A similar effect of ST has not been described in human hypertension. Our purpose was to investigate the influence of WT on this training effect, the influence of ST on LV hypertrophy and the involvement of adrenergic stimuli in the latter. Male SHR (20 weeks old) were divided randomly into 4 groups. 1) SHR sedentary 2) SHR ST 36 degrees 3) SHR ST 26 degrees 4) SHR ST 36 degrees + atenolol (50 mg/kg/die). ST was performed 2 X 90 min/day for 31 days and then reduced to 2 X 60 min/day. After 7 weeks of ST BP was lower in all ST groups compared with SHR sedentary (p less than 0.001). BP was higher in ST 26 degrees than in ST 36 degrees (p less than 0.05). No additional effect of atenolol on BP was observed. The increase in the degree of LV hypertrophy during ST (ST 36 degrees: +15%; ST 26 degrees: +26%) could be prevented by atenolol (ST 36 degrees + atenolol: -1.5%). ST 36 degrees led to improved ventricular and myocardial performance with decreased LV wall stress ("luxury hypertrophy"), while in ST 26 degrees ventricular dilatation occurred with increased systolic wall stress and elevated LVEDP. It was uncertain whether this should be interpreted as a state of LV pre-insufficiency in ST 26 degrees in spite of no indications of impaired myocardial contractile capability. Peripheral vascular resistance (PVR) was significantly reduced by ST. The reduction was more evident in ST 26 degrees, but was partially compensated for by an increased cardiac output. The weights of adrenal glands increased (p less than 0.001), most markedly for ST 26 degrees. The level of thyroid hormones (T3 and fT3) was increased in ST 26 degrees. In summary, ST proved to be effective in lowering BP of SHR. WT had great influence with respect to cardiovascular adaptation and mechanisms involved in ST of SHR. Cardioadrenergic drive was of great significance for the process of hypertrophy during ST in SHR.
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PMID:Significance of physical exercise in hypertension. Influence of water temperature and beta-blockade on blood pressure, degree of cardiac hypertrophy and cardiac function in swimming training of spontaneously hypertensive rats. 294 62

The spontaneously hypertensive rat (SHR) exhibits both a compensated phase of cardiac hypertrophy in which forward output is maintained despite persistently elevated systemic arterial pressures and a decompensated phase in which cardiac performance has deteriorated in spite of further hypertrophic growth. To determine whether chronic antihypertensive therapy prevents the development of heart failure and the progression of cardiac hypertrophy in SHR with advanced hypertension, captopril (2 g/l of drinking water), a converting enzyme inhibitor, was administered to 14 month old female SHR and normotensive American Wistar rats (NWR) for 10 months. The severe left ventricular hypertrophy of the 24 month old untreated SHR (4.37 +/- 0.2 mg/g v. 2.50 +/- 0.06 mg/g, untreated NWR) was markedly reduced (P less than 0.02) by captopril (3.01 +/- 0.1 mg/g). Chronic therapy prevented the reduction of both baseline and maximal cardiac indices in SHR, but did not alter blood flow in NWR. Left ventricular dilatation was present in 24 month old SHR and, as peak stroke volume index was diminished, the ejection fraction index of the SHR was reduced. Captopril restored this index in SHR to normal. The relation of ejection fraction index and afterload (peak systolic wall stress) was depressed in untreated SHR, but was normal in treated SHR. Thus, chronic therapy with captopril prevented the development of severe cardiac dysfunction and produced a marked regression of cardiac hypertrophy in SHR with advanced hypertensive heart disease.
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PMID:Prevention of the development of heart failure and the regression of cardiac hypertrophy by captopril in the spontaneously hypertensive rat. 622 Aug 93

Round heart disease, a presumed viral myocarditis of turkeys, provides a unique opportunity for the study of congestive cardiomyopathy. Regional myocardial blood flow and cardiac output measurements were made in nine, 19 to 34 day old anaesthetised birds using 141Ce labelled microspheres (15 micron diameter). Atrial, right ventricular and weighted-average left ventricular myocardial blood flow values were similar in control (n = 5) and round heart disease (n = 4) turkeys. The left ventricular subendocardial/subepicardial blood flow ratio of 0.89 +/- 0.02 (mean +/- SE) in round heart disease birds was, however, reduced compared with the value of 1.19 +/- 0.09 in the control birds (P < 0.05). Round heart disease turkeys also had lower systemic pressures and lower cardiac outputs when compared with control birds. M-mode echocardiograms were obtained in 42 unanaesthetised 17 to 37 day old turkeys, 34 control and eight with round heart disease. Echocardiographic evidence of left ventricular dysfunction characterised by left atrial and left ventricular dilation and a markedly reduced left ventricular shortening fraction was found in round heart disease turkeys. Paradoxical motion of the interventricular septum was present in two of eight round heart disease turkeys but in none of the control turkeys. The interventricular septum/left ventricular posterior wall ratio in control and round heart turkeys were similar. Although the body weight of control and round heart disease turkeys were similar, and the diastolic thickness of the left ventricular wall were not substantially different, the ventricular weight/body weight ratio in round heart disease turkeys was increased approximately 52%. The increased ventricular weight was not due to myocardial oedema, as myocardial water content was similar in control and round heart disease turkeys. The features which characterise round heart disease in turkeys: left atrial and left ventricular dilatation, reduced left ventricular shortening fraction, systemic hypotension, low cardiac output, relative subendocardial underperfusion, and an increase in ventricular mass, make it a useful model for congestive cardiomyopathy.
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PMID:Regional myocardial blood flow and cardiac function in a naturally occurring congestive cardiomyopathy of turkeys. 745 26

1. The purpose of this study was to investigate the effect of fractional meal stimulation on postprandial haemodynamic changes, the possible correlation between these changes and the potential mediating role of circulating catecholamines and insulin. 2. Healthy young subjects were studied before and after ingestion of isocaloric, isovolumetric high-protein, carbohydrate or fat meals (80-85% of total energy), 60 kJ per kg of body weight. Multigated radionuclide cardiography with autologous 99mTc-labelled erythrocytes was performed for assessment of cardiac output, venous occlusion plethysmography to obtain forearm blood flow and Doppler-ultrasonography for portal vein flow. Plasma levels of catecholamines and insulin were determined by radioimmunoassay. 3. Cardiac output increased considerably after each meal, including the control meal (water) with only minor differences in extent and timing. Left ventricular volumes increased after food intake, most pronounced after carbohydrate and protein. Forearm blood flow increased only after carbohydrate and protein. Portal vein flow increased after all meals, especially after fat, but also after the control meal. There was a significant correlation between the increment in cardiac output and changes in forearm and portal vein flow, but no correlation between either haemodynamic response and plasma catecholamines or insulin. 4. Postprandial cardiovascular changes are not substantially different after various isocaloric and isovolumic meal compositions. Gastric distension seems to play a role in the increase in cardiac output, accomplished by ventricular dilatation. These changes seem to some extent to be linked to changes in muscle and splanchnic flow.
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PMID:Haemodynamic effects of eating: the role of meal composition. 877 33


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