Biomedical subjects

Anil Nanda

Publications and source records attributed to Anil Nanda.

At least 73 records · Page 4Linked to original sources

PubMed2003

Effect of hyperbaric oxygen on apoptosis in neonatal hypoxia-ischemia rat model.

We have previously demonstrated that a transient exposure to hyperbaric oxygen (HBO) attenuated the neuronal injury after neonatal hypoxia-ischemia. This study was undertaken to determine whether HBO offers this neuroprotection by reducing apoptosis in injured brain tissue. Seven-day-old rat pups were subjected to unilateral carotid artery ligation followed by 2 h of hypoxia (8% oxygen). Apoptotic cell death was examined in the injured cortex and hippocampus tissue. Caspase-3 expression and activity increased at 18 and 24 h after the hypoxia-ischemia insult. At 18-48 h, poly(ADP-ribose) polymerase (PARP) cleavage occurred, which reduced the band at 116 kDa and enhanced the band at 85 kDa. There was a time-dependent increase in the number of terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive cells. A single HBO treatment (100% oxygen, 3 ATA for 1 h) 1 h after hypoxia reduced the enhanced caspase-3 expression and activity, attenuated the PARP cleavage, and decreased the number of TUNEL-positive cells observed in the cortex and hippocampus. These results suggest that the neuroprotective effect of HBO is at least partially mediated by the reduction of apoptosis.

Animals↗

PubMed2003

Gamma knife irradiation increases cerebral endothelial expression of intercellular adhesion molecule 1 and E-selectin.

OBJECTIVE: Alterations in multiple functions of the microvasculature occur in response to gamma irradiation and are thought to contribute to radiation-induced end organ damage by inducing inflammatory responses, particularly leukocyte infiltration into the affected area. Endothelial cell adhesion molecules (ECAMs) mediate leukocyte adhesion and migration. Here, we validate a method to study the effect of Leksell gamma knife stereotactic radiosurgery on the expression of ECAMs on human cerebral endothelium at 0, 24, 48, and 72 hours after irradiation. METHODS: A human brain endothelial cell line (IHEC) was cultured on 12-mm coverslips and subjected to 50 Gy of collimated gamma irradiation with the Leksell gamma knife (Elekta Instruments, Inc., Atlanta, GA). Lactate dehydrogenase release was measured at 24, 48, and 72 hours after irradiation and caspase-3 at 24, 48, 72, 96, and 120 hours. ECAM expression was measured at postirradiation intervals of 0, 24, 48, and 72 hours by cell enzyme-linked immunoabsorbent assay. We used a cell irradiator composed of two chambers. The upper chamber holds the coverslips firmly in place while they are immersed in media. The lower chamber is connected to a peristaltic pump, which pumps water into the chamber and maintains the media in the upper chamber at 37 degrees C through convection. RESULTS: None of the ECAMs tested was significantly elevated compared with the control basally. Twenty-four hours after irradiation, intercellular adhesion molecule 1 was significantly elevated on brain endothelial cells but there was no significant elevation of E-selectin. Vascular cell adhesion molecule 1 was increased slightly but not significantly and decreased at 48 hours. At 72 hours, E-selectin expression was significantly increased; intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 were not altered relative to sham controls. CONCLUSION: Increased ECAM expression and lactate dehydrogenase release support the idea that the cerebral microvasculature undergoes an inflammatory response after Leksell gamma knife stereotactic radiosurgery.

Apoptosis↗

PubMed2003

Contribution of Src tyrosine kinase to cerebral vasospasm after subarachnoid hemorrhage.

OBJECT: Mitogen-activated protein kinase (MAPK) has been implicated in cerebral vasospasm after subarachnoid hemorrhage (SAH). This study was conducted to investigate whether Src tyrosine kinase, an upstream regulator of MAPK, is involved in cerebral vasospasm. METHODS: An established canine double-hemorrhage model was used. Twenty-four dogs were divided into four groups: control, vehicle-treated, Src inhibitor PP2-treated, and Src inhibitor damnacanthal-treated groups. Vehicle (dimethyl sulfoxide), PP2, or damnacanthal was injected daily into the cisterna magna of 18 dogs at 3 to 6 days after induction of SAH. Angiography was performed on Day 0 (the day on which the first blood injection was administered to induce SAH) and on Day 7. Western blot analysis of Src and MAPK activation in basilar arteries (BAs) collected on Day 7 post-SAH was performed. Severe vasospasm was observed in the BAs of vehicle-treated dogs. Mild vasospasm was observed in all dogs treated with Src inhibitors. Phosphorylated Src and MAPK were increased after SAH and activation of these kinases in the BAs was abolished by PP2 and damnacanthal. CONCLUSIONS: The tyrosine kinase Src is an important upstream regulator of MAPK, and inhibition of Src might offer a new therapy in the management of cerebral vasospasm.

Animals↗

PubMed2003

The role of multiple hyperbaric oxygenation in expanding therapeutic windows after acute spinal cord injury in rats.

OBJECT: Hyperbaric oxygenation (HBO) therapy has been reported to improve neurological recovery after spinal cord injury (SCI). In the present study, the authors examined whether multiple HBO therapy can expand the therapeutic window after acute SCI. METHODS: Seventy rats were randomly assigned to seven groups: sham surgery; SCI without treatment; single HBO treatment beginning at 30 minutes, 3 hours, and 6 hours after SCI; and multiple HBO treatments starting at 6 and 24 hours postinjury. Mild SCI was induced by adjusting the height of a weight drop (10 g) to 6.25 mm above the exposed spinal cord. A single HBO administration was performed at 2.82 ata for 1 hour. The multiple HBO treatment modality was performed once daily for 1 week. All rats underwent behavioral testing with the Basso-Beattie-Breshnahan locomotor rating scale twice a week. Rats were killed on Day 42 postinjury and specimens comprising the lesioned area were histopathologically examined. Those rats that received single HBO intervention beginning at 30 minutes and 3 hours and those that received multiple HBO treatment starting at 6 hours following injury made significantly greater neurological recoveries than those in the nontreatment SCI group. These rats also retained more sparing tissue than controls. CONCLUSIONS: The results of this study demonstrate that multiple HBO treatments can expand the therapeutic window for acute SCI to 6 hours after injury.

Acute Disease↗

PubMed2002

Spinal epidural abscess: a diagnostic challenge.

Epidural abscess of the spinal column is a rare condition that can be fatal if left untreated. Risk factors for epidural abscess include immunocompromised states such as diabetes mellitus, alcoholism, cancer, and acquired immunodeficiency syndrome, as well as spinal procedures including epidural anesthesia and spinal surgery. The signs and symptoms of epidural abscess are nonspecific and can range from low back pain to sepsis. The treatment of choice in most patients is surgical decompression followed by four to six weeks of antibiotic therapy. Nonsurgical treatment may be appropriate in selected patients. The most common causative organism in spinal epidural abscess is Staphylococcus aureus. Spinal epidural abscess involving actinomycosis is rare.

Actinomycetales Infections↗

PubMed2002

Multiple cavernomas of brain presenting with simultaneous hemorrhage in two lesions: a case report.

BACKGROUND: Cavernomas are rare vascular lesions of the brain that can bleed. However, the risk of bleeding is lower than that of aneurysms or arteriovenous malformations. In selected cases, bleeding cavernomas require surgical management. Presented here is a case of multiple cavernomas of the brain with simultaneous bleeding in two different lesions, along with its management. Although multiple cavernomas have been described in the literature, simultaneous bleeding in two different lesions is rare. CASE DESCRIPTION: A 52-year-old woman presented with difficulty maintaining balance, double vision, and slurred speech. She had had multiple surgeries for cavernous angioma of the brain in the past. Examination and investigations revealed two cavernomas, one in the dorsal midbrain region and one in the left occipital region. Her clinical condition deteriorated suddenly, and further evaluation revealed bleeding in both the cavernomas. The lesion in the midbrain was removed surgically. Since the lesion was in the posterior midbrain, a posterior interhemispheric approach was used with the help of frameless stereotactic navigation. Total excision was achieved. The lesion in the occipital lobe was not operated on. The patient had an uneventful recovery. It was planned to observe the progress of the occipital cavernoma by serial magnetic resonance imaging scans. CONCLUSION: Although there may be simultaneous bleeding in two or even more lesions, surgical treatment should be undertaken for the lesions jeopardizing critical structures or exerting mass effects. Additionally, it was discovered that frameless stereotactic navigation was of immense help in delineating the lesion and for safe excision of the lesion in critical areas.

Brain Neoplasms↗

PubMed2002

Surgical management of unruptured aneurysms: prognostic indicators.

BACKGROUND: The treatment of unruptured aneurysms (UA) remains controversial. Therefore, it has become necessary to define various prognostic indicators in the surgical treatment of unruptured aneurysms not associated with previously ruptured aneurysms. METHODS: During a 6-year period, 78 unruptured aneurysms were managed. The results of management were retrospectively reviewed to define the prognostic indicators. RESULTS: There were 104 patients with unruptured aneurysms who underwent surgical treatment. Seventy-five patients without previous subarachnoid hemorrhage (SAH) were selected for data analysis. Eighty-seven percent of the aneurysms were on the anterior circulation. The most common location was the middle cerebral artery (MCA) followed by the posterior communicating artery (PCom), ophthalmic artery, and anterior communicating artery (ACom). Six percent were found on the basilar artery. The mean size of aneurysms was 12.5 mm (range = 3-30 mm, SD = 7.4). At surgery, rupture of the aneurysm was encountered in eight cases with temporary control of the parent vessel being required in 31 procedures. In four cases, intraoperative angiography warranted clip reapplication. The Glasgow Outcome Scale (GOS) was used as an outcome measure. Surgical treatment resulted in good outcome (GOS 1) in 87% and 10.7% had fair outcome; 2.3% were in GOS 3 (severe disability) at 6 month follow-up. There was no mortality. Logistic regression identified significant relationships between GOS and intraoperative rupture (p < 0.0002), rupture and size (p < 0.003), and size and age (p < 0.01). CONCLUSIONS: Large size aneurysms were associated with intraoperative rupture, which had a strong correlation with poor outcome. Increased age showed a linear relationship with the size of the aneurysm. Overall results of treatment for UA are gratifying. There was no mortality. Early diagnosis and surgical extirpation of UA may reduce both intraoperative difficulties as well as poor outcome probability.

Adult↗

PubMed2002

Selective intraoperative angiography in intracranial aneurysm surgery: intraoperative factors associated with aneurysmal remnants and vessel occlusions.

BACKGROUND: The objective of this study was to assess the role of selective intraoperative angiography and to analyze the factors associated with faulty clip application. METHODS: Two hundred thirty-eight patients undergoing surgery for intracranial aneurysms were studied consecutively for intraoperative angiography (IOA)-related events. The procedure was performed in 155 operations. Demographic details, clinical grade of the patient, location and size of the aneurysm, intraoperative rupture, application of the temporary clip, IOA findings, and final outcome were analyzed. RESULTS: In the 155 patients in the series, there were 125 anterior circulation aneurysms and 30 on the vertebrobasilar system. Aneurysms were smaller than 10 mm in 63% of the patients, and 19 were giant aneurysms. Thirty-eight percent were unruptured, 36% were Hunt and Hess Grades I and II, 21% were Grade III, and 5% were Grades IV and V. An intraoperative rupture occurred in 18 operations. Intraoperative angiography was normal in 88%; in 11 cases (7%) there was a residual neck, and in 8 (5%), occlusion of the artery was observed. An incomplete clipping was significantly related to intraoperative rupture of the aneurysm (p < 0.008) and anterior location of the aneurysm (p = 0.05), whereas vessel occlusion had a significant association with posterior location of the aneurysm (p < 0.0005). An eventful IOA had significant association with poor outcome (p < 0.003). CONCLUSION: Intraoperative rupture and a posterior location of the aneurysm had a significant correlation with residual aneurysm and vessel occlusion, respectively. The use of IOA is justified in aneurysms associated with these factors.

Adult↗

PubMed2002

Primary cerebral sarcoid granuloma: the importance of definitive diagnosis in the high-risk patient population.

Sarcoidosis of the central nervous system has been variously reported in 5-15% of all sarcoid patients. However, presentation of sarcoidosis as an isolated 'intracranial tumor' is rare. A 35-year-old African-American woman presented with intractable headaches. Neuroimaging revealed a tumor that was suggestive of a glioma or meningioma or metastasis. The symptoms did not respond to steroids, and an open biopsy of the lesion revealed non-caseating granuloma. A thorough work-up for systemic sarcoidosis was negative. The patient remains symptom-free at a 2-year follow-up. Primary sarcoid granuloma of the brain is rare. Once systemic disease has been excluded, early tissue diagnosis is crucial. This is particularly relevant for patients in the high-risk population before considering empirical radiosurgery.

Adult↗

PubMed2002

Commentary.

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Journal Article↗

PubMed2002

Commentary.

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Journal Article↗

PubMed2002

Partial labyrinthectomy petrous apicectomy approach to the petroclival region: an anatomic and technical study.

OBJECTIVE: The petroclival region generally is thought to be an inaccessible area in the intracranial compartment. A number of ways of reaching this area during surgery have been described, including the presigmoid petrosal approach. The partial labyrinthectomy petrous apicectomy approach is a relatively new approach to this region and is a variant of the presigmoid petrosal approach. This study aims to demonstrate the technique and the microsurgical anatomy of the partial labyrinthectomy petrous apicectomy approach and to provide a quantitative study of its exposure to compare it with other common approaches to this region, particularly the presigmoid petrosal approach. METHODS: Bilateral stepwise dissections were performed on 15 formalin-fixed and dye-injected cadaveric heads (30 sides) under x3 to x40 magnification. A temporal craniotomy was performed after a complete mastoidectomy. A partial labyrinthectomy and petrous apicectomy were performed next. The amount of dura exposed was measured before and after the partial labyrinthectomy and the petrous apicectomy. By measuring the angles of exposure, the approach was examined to analyze how much increased access was gained. RESULTS: This approach provided wide exposure to the petroclival region, the cerebellopontine angle, Meckel's cave, the cavernous sinus, and the prepontine region. On average, there was an increase of 10.8 mm in horizontal exposure as compared with the retrolabyrinthine approach. The average angle of vision achieved with the clival pit as the target was 58.9 degrees. In most of the specimens, an area from the IIIrd to the IXth cranial nerves was easily visible without any significant brain retraction. A high jugular bulb did not reduce the exposure. CONCLUSION: The partial labyrinthectomy petrous apicectomy approach converts two narrow tunnels into a wide corridor. It increases the angle of exposure markedly, providing easy and excellent exposure of the otherwise difficult-to-access petroclival region, and it may also preserve hearing.

Cranial Fossa, Posterior↗

PubMed2002

Comparison of three rat models of cerebral vasospasm.

A substantial number of rat models have been used to research subarachnoid hemorrhage-induced cerebral vasospasm; however, controversy exists regarding which method of selection is appropriate for this species. This study was designed to provide extensive information about the three most popular subarachnoid hemorrhage rat models: the endovascular puncture model, the single-hemorrhage model, and the double-hemorrhage model. In this study, the basilar artery and posterior communicating artery were chosen for histopathological examination and morphometric analysis. Both the endovascular puncture model and single-hemorrhage model developed significant degrees of vasospasm, which were less severe when compared with the double-hemorrhage model. The endovascular puncture model and double-hemorrhage model both developed more vasospasms in the posterior communicating artery than in the basilar artery. The endovascular puncture model has a markedly high mortality rate and high variability in bleeding volume. Overall, the present study showed that the double-hemorrhage model in rats is a more suitable tool with which to investigate mechanism and therapeutic approaches because it accurately correlates with the time courses for vasospasm in humans.

Animals↗

PubMed2002

Gamma knife radiosurgery for brain metastases: do patients benefit from adjuvant external-beam radiotherapy? An 18-month comparative analysis.

OBJECTIVE: To analyze 18 months of results of gamma knife stereotactic radiosurgery in the treatment of brain metastases and determine factors affecting outcome by examining the effectiveness of additional external-beam radiotherapy (XRT). MATERIALS AND METHODS: Between January 2000 and September 2001, 61 patients with 103 tumors diagnosed as cerebral metastases were treated with gamma knife. Mean patient age was 57 years (range = 36-81). Lung carcinoma (55.7%) was the most common primary cancer, followed by melanoma (14.8%) and breast carcinoma (11.5%). Mean KPS of the patients was 70 (range = 50-90). Twenty-seven patients had solitary metastases while 34 had multiple tumors. Forty-three patients (59 tumors in total) received only radiosurgery, while 18 patients (44 tumors in total) had prior XRT. Tumor volume ranged from 0.5 to 33 cm(3) (mean = 9.74 cm(3)). Mean marginal dose prescription to the tumor was 15 Gy (range = 11-21 Gy). RESULTS: Median follow-up was 11 months. Twenty-one patients (34.4%) were alive at last follow-up and 40 (65.6%) had died. Seventeen deaths (42.5%) were reported to be due to progressive brain disease, while 23 deaths (57.5%) were due to uncontrolled primary. Control of the treated lesions was achieved in 45 patients (73.8%) and 84 tumors (81.6%). Mean overall survival of the patients is 8 months (range = 1-19 months). The actuarial 12-month tumor control rate using the Kaplan-Meier method for this series is 68.2 +/- 0.06%. Results of the log-rank test revealed that younger age (<55 years), small tumor volume (<10 cm(3)), and increasing tumor dose (>15 Gy) correlated with improved brain disease-free survival (p < 0.05). Overall survival, local tumor control rate and the freedom from brain disease period (based on the appearance of new brain tumors after radiosurgery) were analyzed separately for the groups receiving radiosurgery alone and those with prior XRT to detect any additional benefit of XRT. No statistically significant difference was found between the two groups for any of the considered outcomes. CONCLUSION: Gamma knife stereotactic radiosurgery is a safe and effective treatment option for patients with cerebral metastases. It provides survival benefits and improves quality of life by achieving excellent control of the brain disease, irrespective of patients' age or number of brain tumors. The addition of XRT in younger patients with small brain metastases does not improve survival and/or control of the brain disease.

Adult↗

PubMed2002

Far-lateral approach to intradural lesions of the foramen magnum without resection of the occipital condyle.

OBJECT: The goal of this study was to determine whether drilling out the occipital condyle facilitates surgery via the far-lateral approach by comparing data from 10 clinical cases with that from studies of eight cadaver heads. METHODS: During the last 6 years at Louisiana State University Health Sciences Center-Shreveport, 10 patients underwent surgery via the far-lateral approach to the foramen magnum. Six of these patients harbored anterior foramen magnum meningiomas, one patient a dermoid cyst, two patients vertebral artery (VA) aneurysms, and an additional patient suffered from rheumatoid disease of the craniocervical junction. The surgical approach consisted of retromastoid craniectomy and C-1 laminectomy. The seven tumors and the pannus of rheumatoid disease were completely excised, and the two aneurysms were clipped without drilling the occipital condyle. In one patient a chronic subdural hematoma was found 3 months after surgery, but no patient displayed any complication associated with surgery. It is significant that in no patient was a cerebrospinal fluid leak present. All patients experienced improved neurological function postoperatively. To compare surgical visibility, eight cadaveric specimens (16 sides) were studied, including delineation of the VA and its segments around the craniocervical junction. Increase in visibility as a function of fractional removal of the occipital condyle was quantified by measuring the degrees of visibility gained by removing one third and one half of the occipital condyle. Removal of one third of the occipital condyle produced a mean increase of 15.9 degrees visibility, and removal of one half produced a mean increase of 19.9 degrees. CONCLUSIONS: On the basis of their findings the authors conclude that removal of the occipital condyle is not necessary for the safe and complete resection of anterior intradural foramen magnum tumors.

Adult↗

PubMed2002

Anatomical study of the orbitozygomatic transsellar-transcavernous-transclinoidal approach to the basilar artery bifurcation.

OBJECT: An anatomical study in which measurements were obtained was undertaken to demonstrate that the orbitozygomatic transcavernous-transclinoidal approach provides excellent exposure of the trunk of the basilar artery (BA) and its bifurcation. METHODS: Bilateral stepwise dissections were performed on 10 fixed cadaver heads with the aid of x 3 to x 40 magnifications. A frontotemporal craniotomy was made, followed by an orbitozygomatic osteotomy. After the dura mater had been opened, the sylvian fissure was widely separated. The anteromedial triangle of the cavernous sinus was opened to mobilize the internal carotid artery medially. The sella turcica and the dorsum sellae were exposed. The posterior clinoid process and the dorsum sellae were drilled to expose a length of BA that included its bifurcation. Measurements were obtained following the frontotemporal craniotomy, orbitozygomatic osteotomy, and drilling of the posterior clinoid process to quantify the exposures provided by these procedures. Excellent exposure of the trunk of the BA and its bifurcation was achieved. The structures in the interpeduncular cistern and the prepontine cistern were also exposed. There was an average gain of a 13.4-mm-long segment of the BA, which in some surgeries can be invaluable. The angle of exposure that was achieved with the BA bifurcation located at the apex increased markedly. Moreover, this method widened the oculomotor nerve-carotid artery corridor for easier access to the BA bifurcation region. CONCLUSIONS: This approach combines the advantages granted by most conventional approaches to aneurysms of the BA bifurcation. The approach is suitable for aneurysms situated at a high, normal, or low position on the BA bifurcation. It exposes a sufficient length of the BA trunk to place a temporary clip.

Basilar Artery↗

PubMed2002

Autotransfusion by cell saver technique in surgery of lumbar and thoracic spinal fusion with instrumentation.

OBJECT: The authors used a modern cell saver technique to perform autotransfusion in patients undergoing instrument-assisted lumbar and/or thoracic spinal fusion, in whom significant blood loss was anticipated. The safety and benefits of this procedure as well as its cost effectiveness were analyzed. METHODS: The authors studied 50 patients who underwent lumbar and/or thoracic spinal fusion in which instrumentation was placed between January 1998 and June 2000 and in whom an estimated blood loss of 500 ml or more was expected. All surgeries were conducted by a single neurosurgeon (D.R.S.). During surgery, the Brat 2 cell saver system was used to salvage the autologous blood. The anesthesiologist and surgeon jointly decided, on the basis of hematocrit and clinical stability, whether transfusion was necessary in each patient. Various parameters (hematocrit, plasma and urine hemoglobin, platelet counts, coagulation profile, and serum bilirubin) were measured pre-, intra-, and postoperatively. Thirty-three patients (66%) required transfusion. The mean blood loss in these patients was 1046 ml. The most important factor affecting blood loss was the number of levels fused (p < 0.0001). Only two patients required postoperative homologous transfusion. The mean decrease in hematocrit was 7.82%. The maximum reduction of platelet count was limited to 80,000/mm3. Major complications such as hemoglobinuria, coagulopathy, cardiopulmonary problems, air embolism, and major sepsis were not observed in this study. CONCLUSIONS: Autotransfusion performed using a modern cell saver technique is safe and has many advantages over homologous transfusion. It conserves the homologous blood resources. The costs of the two modes are statistically comparable when greater than 500 ml of red blood cell transfusion is necessary.

Adolescent↗

PubMed1998

Traumatic Rupture of Atherosclerotic Plaque Producing Aortic Isthmus Dissection.

Traumatic rupture of aortic isthmus atherosclerotic plaque resulting in dissection has not been documented through the use of either invasive or noninvasive diagnostic modalities. We describe an elderly patient in whom transesophageal echocardiography and three-dimensional reconstruction of multiplane transesophageal two-dimensional images clearly demonstrated the traumatic dissection to be due to rupture of a large atherosclerotic plaque located in the aortic isthmus. The patient had experienced blunt trauma to the chest from the impact of the steering wheel during an automobile accident.

Journal Article↗