Parenchymal Edema Research Articles

Exercise pre-conditioning strengthens brain microvascular integrity in a rat stroke model

Increasing evidence indicates that physical activity reduces brain damage after stroke. The purpose of this study was to determine whether exercise-induced neuroprotection is associated with improved brain integrity in stroke.Adult male Sprague–Dawley rats (3 months old, n=38) exercised on a treadmill, which required repetitive locomotor movement, for 30 minutes each day for 3 weeks. Then, using an intraluminal filament, stroke was induced by either 2 hours middle cerebral artery (MCA) occlusion followed by 24 or 48 hours of reperfusion. Brain damage was determined by evaluating brain infarction and brain edema, as well as ultrastructural alteration in endothelial–matrix–astrocyte interfaces.Pre-ischemic motor exercise significantly (p<0.01) reduced infarct volume in the frontoparietal cortex and the dorsolateral striatum by 79%. By comparing the percentage difference in brain volume between the right (stroke site) and left hemispheres, we demonstrated a significant (p<0.01) reduction in brain edema associated with reduced infarct volume in a 3 week exercise group (Group 1, n=10) and a 3 week exercise plus 3 week rest group (Group 2, n=10). Edema in cortex and striatum was 19 ± 4% without exercise pre-conditioning (n=10), in contrast to 5 ± 3% (Group 1) or 6 ± 4% (Group 2). The thickness of the basal lamina was enhanced by exercise. In ischemic rats without pre-exercise, alterations in microvessel ultrastructure with decreased luminal area, parenchymal edema and swollen astrocyte end-feet, as well as an abnormally thin basal lamina were observed. In contrast, exercise pre-conditioning significantly reduced the ischemic alterations, decreasing brain edema and increasing basal lamina thickness.This study suggests that exercise pre-conditioning reduces brain injury by decreasing cerebral permeability and enhancing brain integrity after stroke. This exercise-induced endogenous neuroprotection could be an effective strategy to ameliorate ischemic brain injury from stroke.

Unknown primary carcinoma, diagnosed as inflammatory breast cancer,and successfully treated with trastuzumab and vinorelbine

Occult breast cancer presenting with axillary lymph node metastases is uncommon, and inflammatory breast cancer (IBC), as a subtype, is quite rare. Here we describe a case of IBC, which arose as an unknown primary carcinoma; the patient presented with axillary lymph node metastasis, and was successfully treated with trastuzumab and vinorelbine. Specifically, a 55-year-old woman presented with right axillary lymphadenopathy. Although she underwent various examinations, the primary site of the disease was not revealed. Axillary lymph node dissection was performed, and the lesion was diagnosed as a poorly differentiated adenocarcinoma. The patient chose to be treated by alternative medicine. About 6 months later, she was referred to our hospital, due to marked bilateral neck and axillary lymph node swelling. She presented with diffuse right breast enlargement, redness, and peau d'orange. Computed tomography (CT) of the breast showed skin thickening and swelling of the right breast.F-18 Fluorodeoxyglucose positron emission tomography (FDG-PET) showed FDG uptake in the right breast. The patient was clinically diagnosed with IBC. Because overexpression of the human epidermal growth factor receptor 2 (HER2) was found in the specimen from her right axillary lymph node, she was treated with trastuzumab and vinorelbine. Two months after the start of chemotherapy, CT revealed a complete response in the lymph nodes, and the skin thickening and parenchymal edema of the right breast had improved. FDG-PET was also performed at this time, and revealed no FDG uptake in either the right breast or the lymph nodes.

Analysis of complications after gamma knife radiosurgery of intracranial meningioma

Purpose/ObjectiveTo evaluate complications after radiosurgery of meningiomas, investigate predicative factors, and compare these risks to radiosurgery of arteriovenous malformations (AVM).Materials/MethodsFrom 1987–1992, 435 meningiomas were managed with Gamma knife radiosurgery at the University of Pittsburgh to a median marginal tumor dose of 15 Gy (range: 8.9–25); a median treatment volume of 5.1 cc (range: 0.47–56.5), and a median maximum dose of 30 Gy (range: 18–50). Median follow up was 33 months (range: 2–164 months). Tumors were treated after subtotal resection in 189 patients and for recurrence after total resection in 26 patients. 56 were associated with NF2. 296 were female and 139 male. A group of 193 AVM radiosurgery patients with >2yr follow-up was used to compare risks of radiation sequelae.ResultsSymptomatic sequelae developed in 21 patients for an actuarial rate of 6.6±1.4 % at 5 years. There were 15 cases of symptomatic parenchymal injury or edema (4.04±1.04%), including 3 patients requiring shunts, and 8 new cranial nerve deficits (2.69±0.95%). Asymptomatic post-radiosurgery imaging changes were identified on follow-up imaging in 15 patients (4.26±1.09%). Multivariate analysis significantly correlated symptomatic sequaelae with 12-Gy volume, isodose, and marginal dose (p = 0.0072, 0.005, 0.0486), while parenchymal injury (excluding cranial neuropathies) correlated with volume and age (p = 0.0007, 0151). When complication risk in 276 of these meningioma patients with >2 yr follow-up were compared to 193 AVM patients in a multivariate model including dose and volume, the risk of symptomatic sequelae was 2.58 times higher for the AVM patients (p = 0.0415) (Table).Conclusions Purpose/ObjectiveTo evaluate complications after radiosurgery of meningiomas, investigate predicative factors, and compare these risks to radiosurgery of arteriovenous malformations (AVM). To evaluate complications after radiosurgery of meningiomas, investigate predicative factors, and compare these risks to radiosurgery of arteriovenous malformations (AVM). Materials/MethodsFrom 1987–1992, 435 meningiomas were managed with Gamma knife radiosurgery at the University of Pittsburgh to a median marginal tumor dose of 15 Gy (range: 8.9–25); a median treatment volume of 5.1 cc (range: 0.47–56.5), and a median maximum dose of 30 Gy (range: 18–50). Median follow up was 33 months (range: 2–164 months). Tumors were treated after subtotal resection in 189 patients and for recurrence after total resection in 26 patients. 56 were associated with NF2. 296 were female and 139 male. A group of 193 AVM radiosurgery patients with >2yr follow-up was used to compare risks of radiation sequelae. From 1987–1992, 435 meningiomas were managed with Gamma knife radiosurgery at the University of Pittsburgh to a median marginal tumor dose of 15 Gy (range: 8.9–25); a median treatment volume of 5.1 cc (range: 0.47–56.5), and a median maximum dose of 30 Gy (range: 18–50). Median follow up was 33 months (range: 2–164 months). Tumors were treated after subtotal resection in 189 patients and for recurrence after total resection in 26 patients. 56 were associated with NF2. 296 were female and 139 male. A group of 193 AVM radiosurgery patients with >2yr follow-up was used to compare risks of radiation sequelae. ResultsSymptomatic sequelae developed in 21 patients for an actuarial rate of 6.6±1.4 % at 5 years. There were 15 cases of symptomatic parenchymal injury or edema (4.04±1.04%), including 3 patients requiring shunts, and 8 new cranial nerve deficits (2.69±0.95%). Asymptomatic post-radiosurgery imaging changes were identified on follow-up imaging in 15 patients (4.26±1.09%). Multivariate analysis significantly correlated symptomatic sequaelae with 12-Gy volume, isodose, and marginal dose (p = 0.0072, 0.005, 0.0486), while parenchymal injury (excluding cranial neuropathies) correlated with volume and age (p = 0.0007, 0151). When complication risk in 276 of these meningioma patients with >2 yr follow-up were compared to 193 AVM patients in a multivariate model including dose and volume, the risk of symptomatic sequelae was 2.58 times higher for the AVM patients (p = 0.0415) (Table). Symptomatic sequelae developed in 21 patients for an actuarial rate of 6.6±1.4 % at 5 years. There were 15 cases of symptomatic parenchymal injury or edema (4.04±1.04%), including 3 patients requiring shunts, and 8 new cranial nerve deficits (2.69±0.95%). Asymptomatic post-radiosurgery imaging changes were identified on follow-up imaging in 15 patients (4.26±1.09%). Multivariate analysis significantly correlated symptomatic sequaelae with 12-Gy volume, isodose, and marginal dose (p = 0.0072, 0.005, 0.0486), while parenchymal injury (excluding cranial neuropathies) correlated with volume and age (p = 0.0007, 0151). When complication risk in 276 of these meningioma patients with >2 yr follow-up were compared to 193 AVM patients in a multivariate model including dose and volume, the risk of symptomatic sequelae was 2.58 times higher for the AVM patients (p = 0.0415) (Table). Conclusions

Breast MR imaging during or soon after radiation therapy.

To investigate the degree and prevalence of radiation-induced changes on breast magnetic resonance (MR) images in patients who were undergoing radiation therapy at that time or soon after, to assess prospectively whether possible radiation-induced effects impair diagnostic accuracy of imaging, and to investigate the prevalence of residual ipsilateral and synchronous contralateral breast cancer in patients undergoing radiation therapy after resection of a supposedly solitary breast cancer. A total of 116 dynamic bilateral breast MR studies were performed during and up to 12 months after radiation therapy in 72 patients who had undergone breast-conservation surgery without preoperative MR imaging. Patients were assigned to four groups according to the time span between imaging and radiation therapy. Structural changes, parenchymal enhancement pattern, and prevalence and imaging features of incidental lesions were analyzed and compared with those of the nonirradiated breast. Radiation therapy led to parenchymal edema and a significant (two-tailed paired Student t test) increase in enhancement rates in the irradiated compared with those in the contralateral breasts during and up to 3 months after radiation therapy. Neither during nor at any time after radiation therapy did the mean enhancement rates reach diagnostically relevant rates. Unsuspected residual or recurrent breast cancers were identified in irradiated breasts of five patients and in contralateral breasts of two patients. False-positive MR findings resulted in a biopsy in three patients with irradiated and in one patient with nonirradiated breasts. There was no difference in enhancement kinetics or morphology of benign or malignant lesions in irradiated versus nonirradiated breasts. Radiation-induced changes occur at MR imaging during or up to 3 months after radiation therapy but are much less severe than reported. Detection and characterization of lesions were feasible with comparable diagnostic accuracies in irradiated and nonirradiated breasts.

How accurate are emergency clinicians at interpreting noncontrast computed tomography for suspected renal colic?

To assess the accuracy of emergency physicians and trainees in the interpretation of noncontrast helical computed tomography (NCHCT) for suspected renal colic by examining the interrater reliability between emergency department (ED) clinicians and radiologists. Information was collected prospectively on all ED patients undergoing NCHCT for suspected renal colic over a 12-month period. Emergency physicians and trainees were asked to report the absence or presence of specific renal parameters (renal tract abnormality, calculus, hydroureter, hydronephrosis, perinephric stranding, and renal parenchymal edema) and nonrenal parameters (nonrenal abnormality, free gas, free fluid, and aortic diameter >3 cm). These reports were compared with the formal radiology report, which was used as the reference standard. The sensitivity, specificity, accuracy, and kappa coefficient were calculated for each of the parameters. Over the 12-month period, 212 patients underwent NCHCT for suspected renal colic, of whom 127 had both ED and formal radiological reporting. There was an excellent degree of interrater reliability between the ED clinicians and the radiologists (kappa > 0.75) for the presence of renal tract abnormality and renal tract calculus. There was intermediate interrater reliability (kappa 0.4-0.75) for nonrenal tract abnormalities, hydroureter, hydronephrosis, and perinephric stranding. Four patients had potentially significant nonrenal abnormalities missed by ED clinicians. Emergency clinicians are able to identify renal calculi with a high degree of accuracy but may miss important nonrenal abnormalities. Therefore, all patients without evidence of renal tract calculus on NCHCT must have early and appropriate follow-up.

Dynamic MRI of breast hardness following radiation treatment.

To evaluate functional microvascular characteristics of breast induration several years after radiation treatment using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) techniques. Fifteen women with moderate or marked breast induration after surgery and radiotherapy for breast cancer (2-15 years) were examined. Images of the irradiated breast (boost and nonboost sites) on short tau inversion recovery (STIR) and DCE-MRI sequences were subjectively evaluated for edema and the presence of enhancement and compared to the contralateral normal breast. Quantitative enhancement parameters-percent enhancing pixels, transfer constant (K(trans)), rate constant (k(ep)), leakage space (v(e)), and maximum contrast medium accumulation (MCMA)-were also compared. No tumor recurrence was seen. Fat necrosis was seen in 2/15 cases. Increased parenchymal edema at the electron boost site was seen in 12/14 patients. Greater enhancement in the irradiated breast was seen in 11/14 evaluable patients. Kinetic parameter estimates including K(trans) were similar except for percent enhancing pixels, which was greater in the irradiated breast at both boost and nonboost sites (P = 0.03 and 0.04, respectively). v(e) and MCMA estimates were greater in breasts with marked induration compared to moderate grades (P = 0.002 and 0.01, respectively). Parenchymal edema may be an important contributor to palpable induration several years after breast radiotherapy. Increased fluid content may be related to increased numbers of perfused microvessels and/or impaired lymphatic drainage.

Magnetic resonance imaging of induration in the irradiated breast

Background: The causes of induration (hardness) in the breast many years after tumour excision and whole breast radiotherapy for early stage breast cancer are not well established. The purpose of this study is to describe morphological magnetic resonance imaging (MRI) appearances and MRI-derived microvascular functional characteristics of the indurated breast several years post-treatment. Patients and methods: Fifteen women with moderate or marked induration at the electron boost site after breast preserving surgery and radiotherapy for early breast cancer (median 6 years; range, 2–15 years) underwent MRI, including 6/15 with very marked breast shrinkage and 8/15 with marked induration. Morphological T1- and T2-weighted and STIR images were obtained followed by a dynamic contrast medium enhanced sequence. The breast skin and underlying parenchyma of the irradiated breast were evaluated for thickening, oedema and the presence of enhancement compared to the contralateral breast. Particular note of boost site findings was made. Results: No evidence of tumour recurrence was seen. Fat necrosis was seen in 2/15 cases. Skin thickening and skin oedema not evident clinically were seen in 11/15 patients. Increased parenchymal oedema at the electron boost site was seen in 12/15 patients. The parenchymal oedema was not confined to the electron boost site, but was strongest in this location in 9/12 patients. Post-contrast images in 12/14 patients showed persistent parenchymal enhancement in nine (marked in three, who also had severe breast shrinkage and marked induration), a finding consistent with, but not diagnostic of tissue fibrosis. Conclusions: Fat necrosis is not likely to contribute to breast induration several years after radiotherapy in more than a minority of patients. Increased fluid content in the breast parenchyma and skin oedema are likely to be more important contributors to palpable induration. Increased fluid content may be related to persistent capillary leakage even many years post-treatment, an expression of radiation-induced vascular injury. Fibrosis cannot be scored directly on MRI, but persistent parenchymal enhancement in a high proportion of post-contrast images is compatible with this pathology.

A Comparison Of Unenhanced Helical Computerized Tomography Findings And Renal Obstruction Determined By Furosemide 99mTechnetium Mercaptoacetyltriglycine Diuretic Scintirenography For Patients With Acute Renal Colic

We assessed unenhanced helical computerized tomography (CT) secondary findings as predictors of renal obstruction as determined by diuretic scintirenography, and determined their reproducibility. We performed a retrospective review of the records of 77 consecutive patients with unenhanced helical CT findings (stones and secondary findings, including renal parenchymal edema, hydronephrosis, hydroureter, perinephric fat stranding, periureteral fat stranding and extravasation) of urinary lithiasis who had also undergone concomitant diuretic scintirenography during the initial emergency room evaluation during a 1-year period. Unenhanced helical CT films were independently reviewed by 2 attending radiologists (blinded to clinical outcome) to determine interobserver variability. The results were compared to those of diuretic scintirenography. Considerable interobserver variability, as evidenced by kappa values ranging from 0.26 to 0.60, existed for the diagnosis of secondary findings associated with urinary lithiasis on unenhanced helical CT. There was no significant difference in terms of CT findings between patients diagnosed by diuretic scintirenography as having high grade/complete obstruction and those with partial obstruction (p values 0.24 to 0.85 for the 6 unenhanced helical CT findings analyzed). Analyses of variance followed by Tukey's pairwise comparisons showed no significant difference in average number of unenhanced helical CT findings between patients with high grade/complete obstruction (mean plus or minus standard deviation 4.4 +/- 1.31), partial obstruction (4.4 +/- 1.30), and decompression/no obstruction (4.2 +/- 1.16). However, the mean number of unenhanced helical CT findings for patients with normal scintirenography/no obstruction (1.9 +/- 1.41) was significantly different from each of the other 3 diuretic scintirenography groups. Separate logistic regression analyses showed that each unenhanced helical CT finding, except for renal parenchymal edema and urinary extravasation, was a significant predictor of "any degree of obstruction" (high grade and partial obstruction groups) compared to "no obstruction" (decompressed and no obstruction groups). Odds ratios (95% confidence interval) ranged from 6.15 (2.25, 16.82) for perinephric fat stranding to 3.41 (1.30, 8.97) for hydroureter. When these analyses were repeated after exclusion of 8 patients with bladder/passed stones, only perinephric fat stranding and periureteral fat stranding remained significant predictors of "any degree of obstruction," with respective odds ratios of 4.21 (1.49, 11.91) and 4.08 (1.31, 12.65). Measures of agreement between trained, independent radiologists with respect to unenhanced helical CT secondary findings show considerable variability. The average number of CT consensus findings is not helpful in differentiating patients with variable degrees of obstruction, except for those with normal scintirenography/no obstruction. Unenhanced helical CT findings, except for renal parenchymal edema and urinary extravasation, are significant predictors of "any degree of obstruction" (high grade or partial obstruction) compared to "no obstruction" (decompressed or no obstruction). Therefore, unenhanced helical CT findings may be useful for identifying patients with any degree of obstruction but do not differentiate between those with high grade and partial obstruction.

Enhanced pulmonary expression of endothelin-1 in an ovine model of smoke inhalation injury.

Recent studies suggest a role of endothelin-1 (ET-1) in mediating airway inflammation and lung injury. The aim of this study was to assess the immunohistochemical expression of ET-1 in the lung following smoke inhalation injury. ET-1 immunoreactivity was assessed in normal sheep (N = 4) and in sheep at 1 (N = 2), 6 (N = 3), 12 (N = 3), and 24 (N = 3) hours after inhalation injury. In normal animals, ET-1 expression was limited to the basal cell layer of the tracheal epithelium, main bronchi, and associated mucous glands. One hour after injury, ET-1 immunoreactivity was enhanced in upper airway epithelium and mucus glands with new expression in bronchioles. Airway smooth muscle, vascular tissue, and alveolar duct smooth muscle cells expressed moderate levels of ET-1 at 12 and 24 hours. ET-1 immunoreactivity was absent in areas of parenchymal edema and inflammation. The pattern of ET-1 expression following inhalation injury suggests that this peptide may contribute to the airway inflammation, mucus secretion, pulmonary hypertension, increased airway resistance, and decreased lung compliance, which are evident in our ovine model of inhalation injury.

Beneficial effects of the radioprotectant 21-aminosteroid U-74389G in a radiosurgery rat malignant glioma model

Purpose: To evaluate the radioprotectant effects of the 21-aminosteroid U-74389G on the rat C6 glioma model after stereotactic radiosurgery. Because radiosurgery causes both tumor cytotoxicity, as well as regional brain edema, we hypothesized that this drug might exhibit advantageous or deleterious effects on healthy and neoplastic tissue. Methods: Rats were implanted with 10 6 C6 glioma cells into the right frontal brain and randomized to a Control Group ( n = 18), radiosurgery on Day 14 (50% isodose = 35 Gy) ( n = 15), or radiosurgery preceded by a single 15 mg/kg intravenous dose of 21-aminosteroid ( n = 27). All animals were killed by 90 days and evaluated for survival, tumor size, the presence or absence of regional parenchymal edema, or radiation-induced vasculopathy. Results: After tumor implantation, median survival in the Control Group was 23 days. Significant improvements in median survival were noted after RS alone (median, 31 days; p = 0.02), and RS plus 21-aminosteroid (median, 59 days; p < 0.0001). In the Control Group, mean tumor diameter was 5.4 mm. After RS alone, the mean diameter was 3.2 mm ( p = 0.002), and after RS plus 21-aminosteroid, 2.9 mm ( p = 0.0002). In the Control Group, the tumor grew as a hypercellular, compact mass. Only 3 of 18 animals had peritumoral edema. In contrast, 7 of 15 animals in the RS group had evidence of edema ( p = 0.006), but rats that received 21-aminosteroid showed no increase compared to controls ( p = 0.38). Similarly, 6 of 15 animals that had radiosurgery alone showed evidence of vasculopathy ( p = 0.005) compared to no animals in the control group and only 2 of 27 aminosteroid-treated animals. Conclusions: The 21-aminosteroid U-74389G exhibits a radioprotectant effect on normal brain tissue, but does not appear to protect the tumor in an in vivo rat radiosurgery model. We believe that the observed beneficial effects on healthy brain led to significant prolongation of animal survival; perhaps, by limiting the adverse effects of high-dose radiosurgery. This radioprotectant should now be evaluated in randomized clinical trials in patients with malignant brain tumors.

Intracranial Inflammatory Pseudotumors: MRI and CT Findings

Purpose : The purpose of this study was to describe the MR imaging and CT findings of intracranial inflammatory pseudotumors.Materials and Methods : We reviewed the MR imaging (n=8) and CT (n=4) studies of eight patients (M:F =4:4, mean age: 41 years) with pathologically proven intracranial inflammatory pseudotumor. The findings were then evaluated with regard to location, shape, MR signal intensity, CT density and degree of contrast enhancement of the lesion, surrounding parenchymal edema, adjacent bone change and the location of accompanying extracranial lesion.Results : In two patients, the parietal convexity was involved unilaterally, with no extracranial mass, and in the other six, the middle cranial fossa was involved unilaterally and extracranial mass was present. The lesion also involved the tentorium in four cases, the cavernous sinus in four, the anterior cranial fossa in one, and the posterior cranial fossa in one. The location of extracranial mass was the mastoid and middle ear cavity in two cases, the infratemporal fossa in two, both the infratemporal fossa and paranasal sinuses in one, and the orbit in one. MR images showed diffuse dural thickening in all eight cases, leptomeningeal thickening in four, and focal meningeal-based mass in two. As seen on T1 weighted images, the lesions were isointense to gray matter in eight cases, and on T2-weighted images were hypointense in seven cases and isointense in one. Marked homogeneous contrast enhancement was seen in all eight cases. The lesions seen on brain CT, performed in two cases, were isodense. Adjacent brain parenchymal edema and the destruction of adjacent bones were each seen in five cases.Conclusion : The characteristic MR findings of intracranial inflammatory pseudotumors are(1) diffuse dural thickening;(2) a focal meningeal-based mass which on T2-weighted images is seen as hypointense; and marked (3) contrast enhancement : these findings are, however, nonspecific. In order to differentiate these tumors, an awareness of these findings is, however, useful.

Pulmonary Fat Embolism Induced Intravenous Injection of Autologous Bone Marrow in Rabbit: CT and Pathologic Correlation

Purpose : To evaluate the correlation between CT and pathologic findings of pulmonary fat embolism in rabbits. Materials and Methods : In 16 rabbits, pulmonary fat embolism was induced by intravenous injection of autol-ogous bone marrow(mean 3.3 mL). Chest CT scans were obtained immediately(within 1 hour), and 1, 3, and 7 days after embolization. The rabbits were divided into four groups. Group 1 underwent CT scanning immedi-ately after embolization, group 2 immediately and 1 day after embolization, group 3 immediately, 1 day and 3 days after embolization, group 4 immediately, 1 day, 3 days and 7 days after embolization. Pathologic speci-mens were obtained immediately after the last CT scan. Results : The earliest CT findings of pulmonary fat embolism in rabbits were peripheral lung lucency(16/16, 1 00 %), perivascular ground-glass (12/16, 75.0 %) and enlargement of the central pulmonary artery(11/16, 6 8 .8 %). Pathologically, perivascular ground-glass opacity correlated with extensive perivascular alveolar con-gestion and enlargement of the central pulmonary artery correlated with perivascular connective tissue edema and reactive pulmonary arterial engorgement. Peripheral lung lucency was probably caused by embolic occlu-sion of the pulmonary artery and decreased perfusion and air trapping induced by arterial and bronchial s-pasm associated with hypoxia. CT scans obtained 1 and 3 days after embolization showed nodules and patchy ground-glass opacity and consolidation. Aggregation of nodules resulted in patch opacities. Pathologically, pul-monary nodules correlated with focal inflammation surrounding an artery and parenchymal opacity correlat-ed with parenchymal consolidation and hemorrhagic edema. CT scans and pathologic specimens obtained 7 days after embolization showed improvement of parenchymal lung abnormalities. Conclusion : Pulmonary fat embolism in rabbits show CT and pathologic findings which vary with dynamic change. Typical earliest findings of pulmonary fat embolism were peripheral lung lucency, perivascular ground-glass opacity and enlargement of the central pulmonary artery.

Abstracts of Literature

Abstracts of Literature

Tissue kallikrein in transplant kidney

Literature survey, thus far, has shown a decrease in the excretion of urinary tissue kallikrein (TK) in transplant patients with a further reduction of the enzyme during episodes of acute rejection. The study aims were to compare, at cellular and subcellular levels, the localisation of tissue kallikrein in biopsies of the transplant kidney to autopsy derived normal renal tissue. Renal biopsies from eighteen transplant patients with deteriorating renal function were obtained. Immunolabelling for tissue kallikrein, using a polyclonal goat anti-TK, antibody raised against recombinant TK, was performed following routine enzymatic, immunofluorescence and electron microscopic techniques. In normal kidney tissue, TK was immunolocalised in the distal connecting tubules and collecting ducts. By comparison the renal transplant tissue showed a reduction in the intensity of label, but maintained the sites of localisation. In the sections examined by electron microscopy, although TK was confined mainly at the luminal side of the cell, some label was noted along the basolateral membranes. In the transplant kidneys, there was a reduction in the overall number of gold particles counted, which correlated with the decreased intensity observed on immunocytochemistry. In addition, there was a shift to a basolateral orientation of the immunolabel. Acute rejection is characterised by oedema, tubulitis and vasculitis. Destruction of the tubule cells and leakage of TK into the interstitial tissue space and the resultant effect of the formed kinins on renal capillary vasculature could explain the observed renal parenchymal oedema and transplant rejection.

Correlation between venous stump pressure and brain damage after cortical vein occlusion: an experimental study.

A canine model of cortical vein occlusion was used to evaluate whether data obtained from monitoring venous stump pressure could help predict cerebral infarction after venous obstruction. Following bilateral parasagittal craniotomy, the cortical vein in each hemisphere was temporarily occluded and the increase in pressure was directly measured. Permanent venous obstruction was subsequently produced, and parenchymal brain damage 24 hours later was classified as: Stage 0, no parenchymal damage; Stage I, mild edema; Stage II, moderate parenchymal edema and/or ischemic changes in neurons; and Stage III, moderate-to-severe hemorrhage. The histological stages correlated closely with the rise in venous pressure: mean pressure increases (+/- standard deviation) were 5.5 +/- 2.9 mm Hg in hemispheres graded as Stage 0 (12 hemispheres), 7.7 +/- 3.2 mm Hg in those graded as Stage I (five), 11.2 +/- 4.1 mm Hg in those classed as Stage II (five), and 16.4 +/- 5 in those categorized as Stage III (seven). There were significant differences between Stages 0 and II (p < 0.01) and between Stages 0 and III (p < 0.001). Disruption of the blood-brain barrier as indicated by extravasation of Evans blue dye correlated well with the pressure increment. These results may indicate the threshold for injury after cortical venous occlusion. Venous stump pressure measurements obtained during a test occlusion may be a useful adjunct in predicting brain damage and may be helpful for intraoperative vessel selection for venous resection.

Cold ischemia–induced damage to vascular endothelium results in permeability alterations in transplanted lungs

Despite suggestions of a connection between endothelial damage and permeability alterations after ischemia and reperfusion in pulmonary tissue undergoing transplantation, no direct correlation between vascular endothelial discontinuity and parenchymal edema has yet been shown. Methods: Forty-two rat lungs were harvested and stored for 48 or 72 hours under hypothermic and ischemic conditions. Stored pulmonary tissue was studied before transplantation and 5 minutes or 24 hours after transplantation by light microscopy and scanning electron microscopy of arterial vascular endothelium. Results: Stored lungs not subjected to revascularization showed moderate perivascular edema, with small intercellular gaps in endothelial monolayers. Five minutes after transplantation, pulmonary tissue appeared congested, with perivascular and alveolar edema. Examination of vascular endothelium by scanning electron microscopy showed detachment of endothelial cells. Twenty-four hours after transplantation, edema, hemorrhage, and vascular congestion were found in all specimens. Arterial vascular endothelium showed weak intercellular connections, numerous intercellular gaps, and widespread cell detachment. Bronchial epithelial cells appeared damaged after storage, with loss of cilia, blebbing of apical cytoplasm, and cellular rounding. These changes were maintained 5 minutes after transplantation but appeared totally reversed after 24 hours in specimens stored 48 hours, whereas bronchial denudation was observed in 72-hour stored lungs. Statistically significant positive correlations (Kendall p < 0.001) between revascularization time and alveolar edema and hemorrhage were found for both storage periods. Conclusion: The results from this study demonstrate correlation between loss of endothelial monolayer continuity and histologic evidence of vascular permeability increases in pulmonary tissue before and after lung transplantation. (J T HORAC C ARDIOVASC S URG 1996;112:1027-35)

Transcranial color-coded duplex sonography in cerebral arteriovenous malformations.

It is well known that significant changes in cerebral hemodynamics may occur during the treatment of cerebral arteriovenous malformations with the complication of intracerebral hemorrhage and parenchymal edema. We used transcranial color-coded duplex sonography to study alterations in blood flow velocities during staged embolization. Forty-one patients aged 40 +/- 13 years (mean +/- SD) with angiographically proven cerebral arteriovenous malformations were studied. The blood flow velocities of the anterior, middle, and posterior cerebral arteries were measured in 16 patients with supratentorial arteriovenous malformations, both before the first and then after each successive embolization (three to seven treatments). In 29 of 41 patients (71%), transcranial color-coded duplex sonography satisfactorily revealed the malformations and their main feeders. After the final embolization, we found a reduction in the peak flow velocity in treated feeders of 23 +/- 28% compared with the values before the first embolization. The untreated feeders showed an increase in peak flow velocities of 12 +/- 23% as an expression of increased collateral flow. After the treatment of the supplying feeders, we observed a reduction in flow velocity of 25 +/- 13% in seven patients, with cross-filling of the arteriovenous malformation through the contralateral anterior cerebral artery and the anterior communicating artery. The technical advantage of transcranial color-coded duplex sonography compared with transcranial Doppler sonography is that it allows the exact identification of different feeding arteries in arteriovenous malformations. Repeated measurements during stepwise embolization with corrected insonation angle are easily achieved, and noninvasive quantification of hemodynamic changes is possible. The method may be helpful in the planning of the different steps of embolization.

Primary Angiitis of the Central Nervous System: Report of Two Cases and Review of the Literature

Two cases of primary angiitis of the central nervous system with subarachnoid hemorrhage are reported. One patient was admitted with very thin and localized sulcal subarachnoid hemorrhage, followed by the development of multiple parenchymal edema. Although the first angiography showed only a mild narrowing of an artery, the second angiography demonstrated multiple segmental narrowings of arteries. An open biopsy failed to show histological changes. The second patient suffered from sylvian subarachnoid hemorrhage along with multiple intracerebral hemorrhages, with angiography that was diagnostic for angiitis. In both cases, predonine was initiated and further angiography clearly demonstrated a resolution of the angiitis. The usefulness of serial angiography for diagnosis in comparison with surgical biopsy and for monitoring the treatment of this disease is discussed. The occurrence of subarachnoid hemorrhage in this disease is also reviewed.

Pulmonary interstitial edema in the pig after heavy exercise.

During exercise (especially in hypoxia), the alveolar-arterial O2 tension difference increases. This impairment of pulmonary gas exchange is caused partly by diffusion disequilibrium, but it has also been shown that an exercise-induced increase in ventilation-perfusion (VA/Q) inequality develops. Possible explanations of increased VA/Q mismatch include nonuniform pulmonary vasoconstriction, reduced gas mixing in the large airways, airway obstruction, and the development of interstitial pulmonary edema. To directly determine whether the latter develops in high-intensity short-term exercise, we exercised pigs on a motor-driven treadmill at the highest speed that they could sustain for 6-7 min. Heart rate reached 274 +/- 5 min-1 in the exercised group, confirming that the pigs reached a near-maximal level of exercise. While running, the pigs were killed by an intravenous overdose of pentobarbital. Postmortem, the lungs were immediately removed, drained of blood, weighed, and then airway fixed with 10% formaldehyde. Four tissue blocks of the right lung of each pig were taken from the ventral and dorsal areas of the upper and lower lobes, respectively. They were stained with hematoxylin and eosin and prepared for histological examination by light microscopy. There was no difference in the lung-to-body weight ratio between exercised pigs (7.72 +/- 0.87 g/kg) and a nonexercised control group (7.70 +/- 0.68 g/kg). However, we found a significantly higher percentage of pulmonary arteries with perivascular edema in exercised (33.8 +/- 3.4%) than in nonexercised pigs (20.0 +/- 4.0%; P < 0.02). Thus, perivascular edema (and thus possibly also parenchymal interstitial edema) can occur during short-term heavy exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Bronchial Artery Embolization on the Plain Chest Radiograph

The bronchial circulation may influence pulmonary edema. This study evaluates possible effects of bronchoesophageal artery embolization on the plain film manifestations of hydrostatic pulmonary edema in sheep. Anteroposterior and lateral chest radiographs were obtained during the induction of pulmonary edema both before and after embolization of the bronchoesophageal artery in six adult sheep. Interstitial lines and perivascular, segmental bronchial, proximal bronchial, carinal, tracheal, and parenchymal edema were evaluated. Only parenchymal edema was graded consistently. Though edema increased with left atrial pressure before embolization (P < .001), there was no similar change afterward. The embolized animals tended to be more edematous by the first film. Rather than any protective effect, bronchoesophageal artery embolization may increase edema. This model may be inappropriate for further investigation of the bronchial circulation in the development of human pulmonary edema.