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Biomedical subjects

D Zagzag

Publications and source records attributed to D Zagzag.

67 records · Page 4Linked to original sources
PubMed1989

Angiogenesis and blood-brain barrier breakdown modulate CT contrast enhancement: an experimental study in a rabbit brain-tumor model.

Because of the crucial role played by tumor neovascularization in contrast enhancement, we studied the CT imaging findings in a transplantable rabbit brain tumor, the VX2 carcinoma that induces angiogenesis and the breakdown of blood-brain barrier associated with contrast enhancement. Tumor detection by contrast enhancement followed the peak of angiogenesis. Inhibition of angiogenesis, by copper depletion and penicillamine, led to avascular tumors that lack contrast enhancement. Furthermore, there was no contrast enhancement in brain adjacent to the tumor of normocupremic rabbits or within the hypocupremic tumor, despite the breakdown of the blood-brain barrier, without the concomitant presence of angiogenesis. We conclude that contrast enhancement of intracranial tumors is dependent primarily on the proliferation of the microvasculature.

Animals↗
PubMed1988

Neovascularization and tumor growth in the rabbit brain. A model for experimental studies of angiogenesis and the blood-brain barrier.

A model for the study of tumor angiogenesis within the rabbit brain is presented. Implantation of the VX2 carcinoma provides a reproducible tumor accompanied by angiogenesis. The authors report the sequential growth, histology, tumor neovascularization, and vascular permeability of this tumor following its intracerebral implantation. Tumor angiogenesis correlates with the rapid and logarithmic intracerebral tumor growth. The proliferation of blood vessels in the tumor and the organization of tumor cells around tumor vessels are described. Breakdown of the blood-brain barrier (detected by Evans blue leakage) starts in the early stages of tumor development and becomes prominent as the tumor vasculature and size increase. This model is useful for experimental studies of angiogenesis.

Animals↗
PubMed1986

Randomized clinical trial of intra-operative antimicrobial prophylaxis of infection after neurosurgical procedures.

A randomized, placebo-controlled, double-blind and sequentially analysed clinical trial to determine the efficacy of intra-operative parenteral gentamicin and vancomycin (with streptomycin in the irrigating solution) in preventing infection at the operative site following neurosurgical procedures is described. Patients receiving prophylaxis had a significantly (P = 0.046) lower operative site infection rate (2/71 = 2.8%) than those receiving placebo (9/77 = 11.7%). This difference was most apparent during an epidemic, the source of which was not evident. Moreover, a total of 13 infections (two operative site, five pneumonia and six urinary tract) occurred among 12 patients receiving prophylaxis, whereas there was a total of 31 infections (nine operative site, nine pneumonia, 10 urinary tract and three septicaemia) among 24 patients receiving placebo. A smaller quantity of antimicrobial drugs was administered postoperatively to patients receiving prophylaxis (3.96 'antibiotic-days' per patient) than to those receiving placebo (6.87 'antibiotic-days' per patient).

Anti-Bacterial Agents↗
PubMed1985

Hyperostotic meningioma presenting as an asymptomatic forehead bulge in a 7-year-old girl.

The case of an asymptomatic 7-year-old girl with a hard bulge in the left forehead is presented. The radiological evaluation disclosed a hyperostotic mass with a large intracranial extension. A surgical specimen revealed a meningioma. The presence of a localized cranial bulge as the only sign of an intracranial tumor and the diagnostic value of computerized tomography (CT) are discussed.

Child↗
PubMed1985

A chronically implanted delivery system of drugs to a nerve-end neuroma: effects on a behavioural chronic pain model.

Autotomy has been suggested as an animal model of chronic pain. It starts about a week or two postoperatively and develops until 10 weeks after nerve section. This behaviour is thought to be triggered by activity of sensory fibres ending in a neuroma. Here we suggest to utilize it in combination with a novel drug delivery system which enables a direct and exclusive access of the drug to the neuroma. Alteration in the autotomy behaviour can then be related to the exclusive topical action on the sensory fibres within the neuroma. The sciatic nerve is transsected and its proximal end inserted into a PE tube sealed distally. A second, smaller tube originates in a wound exit in the back of the animal and subcutaneously leads into the large tube, where it is fixed by glue to the inner wall. Thus, the end of the smaller tube is juxtaposed to the nerve end. During the following weeks a neuroma develops within the tube. The resulting autotomy scores are then examined weekly. At various times after the operation, under light anaesthesia, drugs can be injected into the tube and the effect on the autotomy behaviour is monitored. An example is given, describing the autotomy suppressive effects of glycerol and alcohol, injected to different groups of rats immediately after the operation and compared to an injection 14 days postoperatively. This method is suggested as a pharmaco-behavioural assay for the assessment of the analgetic efficacy of drugs for chronic pain.

Amputation Stumps↗
PubMedDate not supplied

Tenascin-C expression in ultrastructurally defined angiogenic and vasculogenic lesions.

Tenascin-C (TN) is an extracellular matrix glycoprotein expressed during embryogenesis. Its distribution is restricted in normal adult tissues and is upregulated in tumors and inflammatory conditions. Twenty-five specimens were studied, including 7 reactive vascular lesions (6 cases of granulation tissue and 1 case of bacillary angiomatosis), and 18 vascular tumors (6 angiosarcomas, 7 hemangioendotheliomas, and 5 AIDS-related nodular type Kaposi's sarcomas). Formalin fixed-paraffin-embedded tissues were stained with monoclonal antibody to TN (DAKO) and with MIB-1 (AMAC). Heterogeneous expression of TN immunoreactivity was seen in all cases, with a diffuse pattern in bacillary angiomatosis and most granulation tissue cases and a focal pattern in angiosarcoma and most hemangioendothelioma cases. Kaposi's sarcoma cases showed both a focal and diffuse pattern of distribution. In most cases proliferation indices (PI) did not correlate with TN expression. Electron microscopy demonstrated active angiogenesis in bacillary angiomatosis and granulation tissue and vasculogenesis in angiosarcoma and hemangioendothelioma. The study demonstrated positive TN expression in reactive lesions with angiogenesis (granulation tissue and bacillary angiomatosis) and neoplastic lesions showing vasculogenesis (angiosarcoma and hemangioendothelioma), although with a different pattern of distribution. These results suggest that TN might be an important extracellular matrix glycoprotein in angiogenesis and vasculogenesis.

Angiomatosis, Bacillary↗
PubMedDate not supplied

Dynamic contrast-enhanced T2*-weighted MR imaging of tumefactive demyelinating lesions.

PURPOSE: Dynamic contrast-enhanced T2*-weighted MR imaging has been helpful in characterizing intracranial mass lesions by providing information on vascularity. Tumefactive demyelinating lesions (TDLs) can mimic intracranial neoplasms on conventional MR images, can be difficult to diagnose, and often result in surgical biopsy for suspected tumor. The purpose of this study was to determine whether dynamic contrast-enhanced T2*-weighted MR imaging can be used to distinguish between TDLs and intracranial neoplasms that share common features on conventional MR images. METHODS: We retrospectively reviewed the conventional and dynamic contrast-enhanced T2*-weighted MR images and medical records of 10 patients with tumefactive demyelinating disease that was diagnosed by either biopsy or strong clinical suspicion supported by laboratory evaluation that included CSF analysis and evoked potential tests. Twelve TDLs in 10 patients and 11 brain tumors that appeared similar on conventional MR images were studied. Relative cerebral blood volume (rCBV) was calculated from dynamic MR data and was expressed as a ratio to contralateral normal white matter. rCBV values from 11 patients with intracranial neoplasms with very similar conventional MR imaging features were used for comparison. RESULTS: The rCBV values of TDLs ranged from 0.22 to 1.79 (n = 12), with a mean of 0.88 +/- 0.46 (SD). The rCBV values of intracranial neoplasms ranged from 1.55 to 19.20 (n = 11), with a mean of 6.47 +/- 6.52. The difference in rCBV values between the two groups was statistically significant (P =.009). The difference in rCBV values between TDLs and primary cerebral lymphomas (n = 4) was less pronounced but was statistically significant (P =.005). CONCLUSION: Dynamic contrast-enhanced T2*-weighted MR imaging is a useful diagnostic tool in differentiating TDLs from intracranial neoplasms and may therefore obviate unnecessary surgical biopsy.

Adolescent↗
PubMedDate not supplied

A morphologic study of the vasculature of malignant gliomas using thick celloidin sections and alkaline phosphatase stain.

The combination of 100 microm thick celloidin sections and alkaline phosphatase (AP) enzyme histochemistry of the vascular endothelium offers a greatly enhanced, 3D morphologic perspective and reveals intricate details of the vasculature of brain. A study of tumor specimens obtained at craniotomy from 6 patients with glioblastomas, 1 with anaplastic oligodendroglioma and 1 with juvenile pilocytic astrocytoma was undertaken using this technique. Five of the 6 glioblastomas, the anaplastic oligodendroglioma and the low-grade astrocytoma specimen showed uniform staining of afferent tumor blood vessels. In the glioblastomas, newly formed vessels formed dense, festooned networks at the advancing edges of the tumor. Feeding arteries entered the tumor at the junction between the edge of the tumor and adjacent brain or meninges and proceeded to form striking, coiled vessels and smaller branches. The density of both small arteries and veins was greatly increased within the tumor although there was much variability. Disordered arborization, arteriole to venous and arteriole to arteriole shunts were observed, leading to a situation where arteries connected directly to veins. In necrotic areas, there were often no AP-stained vessels. In many places, arterioles and capillaries were lacking. Numerous AP-negative veins of various sizes drained the tumors. Glomeruloid proliferations were presumptively identified as focal stain smudges or clusters of capillaries arising from nearby vascular channels. Increased alkaline phosphatase staining and/or focal new vessels were seen outside necrotic areas. The pilocytic astrocytoma and the oligodendroglioma showed less dense vascularity and no formation of the focal festoons of vessels shown by the glioblastomas. This technique may be useful for the study of tumor angiogenesis and to evaluate vascularity in experimental and human brain tumors after various therapies.

Adult↗
PubMedDate not supplied

Percutaneous chemical lumbar sympathectomy with alcohol with computed tomography control.

Percutaneous chemical lumbar sympathectomy with alcohol (PCLSA) using computed tomography (CT) control was performed in 8 patients suffering from advanced peripheral arterial occlusive disease. PCLSA under CT guidance was found to be a simple and safe procedure. The use of CT control added precision in the guidance of needle placement. Positive results were obtained in all patients, without significant morbidity. PCLSA may be an alternative to surgical sympathectomy.

Adult↗
PubMedDate not supplied

Disseminated calcification with predominant muscle and cerebral involvement in a child with acquired immunodeficiency syndrome: a case report.

Calcification, as a feature of the vasculopathy, is a common pathological finding in children with acquired immunodeficiency syndrome. Large and small blood vessels of many organs including brain, heart, lungs, kidneys, liver, and spleen are affected. We report a case with calcification in multiple organs that was most prominent in the cardiac and skeletal muscle cells and the blood vessels of the cerebrum. To our knowledge, calcification of this degree has not been documented previously in a human immunodeficiency virus-infected child.

Acquired Immunodeficiency Syndrome↗