Biomedical subjects
Publications and source records attributed to Anil Nanda.
The present study demonstrates the feasibility of delineating the carotid bulb and the proximal portions of the left external and left internal carotid arteries during transesophageal examination. This was accomplished by slowly and carefully withdrawing the probe from the esophagus into the pharynx.
We describe our preliminary experience in assessing normal and stenosed coronary arteries using transesophageal three-dimensional echocardiography (3-D echo) in 27 adult patients. Multiplane transesophageal two-dimensional images of the coronary arteries (20 left, 3 right, 3 both left and right, and 1 posterior descending) were first acquired in the TomTec computer in 3 degrees sequential increments, from 0 degrees to 180 degrees, and then 3-D reconstruction was performed. The entire left main (LMC, measuring 0.5 to 1.7 cm, mean 1.0 cm) as well as variable lengths of proximal or both proximal and middle segments of the left anterior descending (LAD, measuring 0.2 to 2.5 cm, mean 0.8 cm) and circumflex (LCX, measuring 0.2 to 2.8 cm, mean 0.9 cm) coronary arteries together with some of their branches could be visualized in 3-D in 22 of 23 patients. In the remaining patient, the LMC was absent, and both LAD and LCX could be visualized in 3-D as having separate but adjacent origins from the left sinus of Valsalva (proven by angiography). In two patients, long segments of interventricular and great cardiac veins were also visualized accompanying the LAD and LCX, respectively. The right coronary artery (RCA, measuring 0.7 to 3.0 cm, mean 1.9 cm) was also successfully delineated in 3-D in all six patients in whom an attempt was made to visualize it during echo examination. Using the transgastric approach, a long (1.8 cm) segment of the posterior descending branch (PDA) of RCA was imaged in one patient. In addition, nine significantly stenotic lesions (>50% lumen diameter) were identified by 3-D in eight patients involving LMC (1), proximal LAD (1), mid LAD (1), proximal LCX (2), proximal RCA (3), and mid PDA (1). Eight of these 9 lesions were confirmed by coronary angiography. The remaining lesion (mid PDA) could not be confirmed since the patient did not undergo angiography. Our preliminary study demonstrates the usefulness of transesophageal 3-D echo not only in delineating normal coronary arteries but also diagnosing significant atherosclerotic stenosis in these vessels. (ECHOCARDIOGRAPHY, Volume 13, September 1996)
OBJECTIVE: The early management of posthemorrhagic hydrocephalus in premature infants is challenging and controversial. These infants need a temporary cerebrospinal fluid (CSF) diversion procedure until they gain adequate weight, and the blood and protein levels in CSF are reasonably low before permanent shunt can be placed. Various options are available with their associated advantages and disadvantages. Ventriculosubgaleal shunts have been recommended as a more physiologic and less invasive means of achieving this goal. We have performed this procedure in 6 premature infants to evaluate their effectiveness and complications. METHODS: Six consecutive premature infants with posthemorrhagic hydrocephalus underwent placement of ventriculosubgaleal shunts over a 1-year period of time. We reviewed their clinical and imaging progress to assess the ability of the shunt to control hydrocephalus and the complication rates. RESULTS: In all 6 patients, the ventriculosubgaleal shunt controlled the progression of hydrocephalus as assessed by clinical and imaging parameters. A permanent shunt was avoided in 1 patient (16.6%). However, 4 patients developed shunt infections, 1 involving the ventriculosubgaleal shunt itself, and 3 immediately after conversion to ventriculoperitoneal shunt. The total infection rate of the series was 66.6%. All infections were caused by staphylococcus species. There was only a 1% shunt infection rate in our institution for all nonventriculosubgaleal shunts during the same period of time. CONCLUSION: Placement of ventriculosubgaleal shunts for interim CSF diversion in neonates with posthemorrhagic hydrocephalus is effective as a temporary method of CSF diversion. However, our experience has shown that it is associated with a unacceptably high CSF infection rate. A potential cause for infection is CSF stasis just beneath the extremely thin skin of the premature infants, promoting colonization by skin flora. CSF sampling before conversion to a permanent shunt and replacement of the proximal hardware, which has been in situ for a prolonged period, may decrease the infection rates. At present, the procedure is no longer performed at our institution.
Louisiana's first ever Leksell Gamma Knife was commissioned at Louisiana State University Health Sciences Center (LSUHSC) in Shreveport in January 2000. Between January 2000 and January 2001,113 patients with various indications were treated using the 201-source Co-60 Leksell model "B" Gamma Knife (Elekta Instruments, Atlanta, Georgia) at LSUHSC-Shreveport. Sixty-three patients were female and 50 were male. The patient age ranged between 13 and 87 years (mean age = 57 years). Fifty-eight (51.3%) patients received radiosurgery as the first line of treatment for their disease, while 55 (48.7%) had previous operations or radiation therapy. The median Karnofsky Performance Score of the patients was 80 (range = 70 to 100). Cerebral metastases were the main indication for radiosurgery at our center accounting for 35% of the patients, while meningioma, arteriovenous malformation, trigeminal neuralgia, and primary central nervous system malignant tumors were the other indications.
Intramedullary spinal cord metastasis (ISCM) is a rare condition that causes serious diagnostic and therapeutic problems. ISCM is usually discovered in less than 1% of autopsies, with fewer than 5% being diagnosed antemortem. The uncertain and non-standardized treatment of patients diagnosed with ISCM is a major concern of neurosurgeons today. Presented is a case of ISCM detected in an 80-year-old man with a history of lung carcinoma. The progression of his illness, diagnostic role of MRI, and ISCM management options are discussed.
Spontaneous regression of the herniated lumbar discs is a well-established phenomenon. This phenomenon of disappearance of the disc has been reported occasionally in the cervical spine and very rarely in the thoracic regions. In this article, we report the rare occurrence of spontaneous resolution of one large herniated cervical disc (C6-7) with simultaneous progression of another disc prolapse (C4-5) in a 46-year-old man.
OBJECTIVE: Secondary prostate cancer affection of the cauda equina (SPCCE) can be an ultimate cause of morbidity and mortality. Since the results of management of this particular disease condition remain largely unknown, a retrospective case review was undertaken to determine the effects of treatment by radiation in SPCCE patients. METHODS: The records of 12 patients with SPCCE treated at the Division of Therapeutic Radiology during the period 1984 to 1998 were reviewed. The administered total radiation dosage ranged from 6 Gy to 32 Gy (average, 26.6 +/- 2.0 Gy). Two individuals underwent decompressive laminectomy and bilateral orchiectomy at the time of SPCCE and prostate cancer diagnoses. Ten patients had prior hormonal manipulative treatment (orchiectomy, estrogen, or Flutamide therapy). RESULTS: Pain was relieved in three of four symptomatic patients (75%). Five of nine patients unable to walk before therapy could walk after treatment. One of two individuals with anal or bladder sphincter dysfunction improved following irradiation. The overall mean duration of survival was five months. With treatment, survival was approximately three times as long for ambulatory versus non-ambulatory patients. CONCLUSION: We conclude that radiation treatment is efficacious in promoting palliation of SPCCE, although it may not prolong life.
OBJECTIVE: Pilocytic astrocytomas are typically circumscribed, slow growing tumors found in children and young adults. This type of tumor can arise from various locations in the neuraxis. In the brainstem, pilocytic astrocytomas grow as dorsal exophytic masses. To our knowledge, pilocytic astrocytomas arising entirely within the brainstem have not been reported in the literature. CLINICAL PRESENTATION: A 22-year-old man presented with double vision for three months. A neurological exam revealed a right sixth nerve palsy. INTERVENTION: Magnetic resonance imaging revealed an intra-axial mass with a cystic center arising from within the brainstem. Intraoperative findings confirmed an intra-axial brainstem tumor. Histological analysis revealed that the tumor was a low-grade glioma most consistent with a pilocytic astrocytoma. CONCLUSION: This case report confirms that pilocytic astrocytomas can present as brainstem gliomas, and histopathology plays a major role in determining the aggressiveness of operative intervention.
Pharmacological therapy for essential tremor (ET), the most common movement disorder, remains largely unsatisfactory. Surgical options such as radiofrequency or thermocoagulation are only suitable for a select group of patients, the young and those free of pre-existing medical conditions. Radiosurgery using the Leksell Gamma Knife has recently gained acceptance as a viable treatment option for tremor control in ET patients. We describe our experience with the first reported ET patient treated with radiosurgery in Louisiana.
BACKGROUND: Glioblastoma multiforme (GBM) is a high-grade primary brain tumor that is refractory to current forms of treatment. In cell studies, the growth rate of GBM cells correlates with the level of Cyclooxygenase-2 (COX-2) enzyme expression. COX-2 has been implicated in carcinogenesis of systemic cancers. Recently, COX-2 inhibition has been shown to increase the radiosensitivity of various tumors. We wished to assess whether the expression of COX-2 is greater in radioresistant versus radiosensitive forms of GBM. MATERIALS AND METHODS: The radiosensitive (A172) and radioresistant (T98G) Glioblastoma multiforme cell lines were assayed for COX-2 expression using standard immunofluorescence histochemistry. Fluorescence readings were recorded per field. Western blot analysis was performed on both A172 and T98G GBM cell lines. The radioresistant cells were exposed to incremental doses of radiation in the presence and absence of a COX-2-selective inhibitor. Radioresistant cells were then exposed to incremental doses of COX-2-selective inhibitor at a constant dose of radiation. RESULTS: The radioresistant cell line T98G had an approximate 1. 7-fold greater expression of COX-2 than did the radiosensitive cell line A172, as per immunofluorescence histochemistry. Western blot analysis confirmed this finding. Statistical analysis (Bonferroni/Dunn) showed the results to be significant (p<0.0001). The wells containing radioresistant cells exposed to incremental doses of radiation and COX-2 inhibitors appeared to have higher cell kill when compared to radiation alone. Furthermore, increasing the COX-2 inhibitor concentration yielded higher cell kill. CONCLUSION: The results presented here show that the radioresistant GBM cell line, T98G, has a greater expression of COX-2 than does the radiosensitive GBM cell line, A172. These results suggest that: (i) COX-2 expression may serve as a marker for assessing radioresistance in GBM, (ii) COX-2 inhibition may lower the required doses of postoperative radiation, (iii) COX-2 inhibitors may have a role in radiosensitizing otherwise radioresistant forms of GBM.
Tethered cord syndrome (TCS) is a rare entity in adults, with only about 100 cases being reported in the literature. It is a syndrome in which patients have neurologic, urologic, and orthopedic signs and symptoms. We present a case of a 40-year-old man with back pain and urinary incontinence who was diagnosed with tethered cord syndrome. After the cord de-tethering in the operating room, his pain improved. TCS is an important condition to consider in the differential diagnosis of an adult who presents with back pain and urological symptoms. Imaging studies should be done, and operative treatment may be required to alleviate the symptoms. TCS should be in the differential diagnosis of any patient who presents with back and lower extremity complaints with superimposed urological problems. If TCS is confirmed radiologically by MRI, surgery can be performed with reasonable results provided that the disease process has not progressed.
BACKGROUND: Elevated Cyclooxygenase-2 (COX-2) expression is thought to increase metastatic potential of many tumors. Furthermore, elevated COX-2 expression correlates with radiation resistance in many tumor types. We evaluated whether: (i) the degree of COX-2 expression correlated with either metastatic tumor type or with the presence of necrosis and whether (ii) radiation-resistant tumors (renal cell and melanoma) had higher expression of COX-2 than did relatively radiation-sensitive tumors (breast and lung). MATERIALS AND METHODS: Specimens from sixteen patients who underwent resection of brain metastases were analyzed for COX-2 expression using a COX-2 antibody-based immunoassay. Specimens consisted of brain metastases from lung tumors, breast adenocarcinomas, melanomas and renal cell carcinomas. All specimens were analyzed for the presence or absence of necrosis. RESULTS: Ten of sixteen brain metastasis specimens had ten percent or less Cox-2 immunostaining. Statistical analyses showed no correlation between Cox-2 immunostaining and metastatic tumor type or between Cox-2 immunostaining and necrosis in this study. Furthermore, renal cell carcinoma and melanoma showed variable Cox-2 immunostaining. CONCLUSION: Cox-2 is not consistently expressed in metastases to the brain. The degree of Cox-2 expression does not correlate with metastatic tumor type or with the presence of necrosis. Radioresistant tumors did not have statistically different expression of Cox-2 than radiosensitive specimens studied in this analysis.