Biomedical subjects

R Arunkumar

Publications and source records attributed to R Arunkumar.

3 recordsLinked to original sources

PubMed1999

Efficiency of supercritical fluid extraction for determining 4-nonylphenol in municipal sewage sludge.

When the sewage sludge containing the persistent, lipophilic, metabolite 4-nonylphenol (4-NP) has been disposed of in the environment it's toxic nature can lead to serious health risks to human beings and can also affect plants and aquatic organisms. Supercritical fluid extraction (SFE) is a new and powerful technique for extracting the organic contaminants from the solid phase. The present study was conducted to investigate optimal conditions for the quantitative extraction of 4-NP by SFE and to determine the concentration of 4-NP in municipal sewage sludge. The effect of several parameters such as temperature, pressure, static extraction time, dynamic extraction time, CO2 flow-rate, sample mass and modifier on the extraction were investigated. The optimal conditions for the extraction of the spiked sample were fluid pressure 97 bar, temperature 40 degrees C, flow-rate 3.0 ml/min, static extraction time 2 min, dynamic extraction time 5 min and modifier methanol (0.5 ml). Extracts were analyzed by gas chromatography-mass spectrometry. Concentration of 4-NP in the anaerobically degraded sludge of the De-Haw Sewage Treatment Plant in Taiwan was found to be 243.9 mg/kg. The extraction efficiency of the SFE method was compared with the conventional Soxhlet extraction method. The overall recovery of the SFE method was found to be greater and the results indicate that SFE is an efficient method for extracting 4-NP from sewage sludge.

Carbon Dioxide↗

PubMed1997

Classification and treatment of vertebral dissecting aneurysm.

BACKGROUND: For many years, dissecting aneurysms of the intracranial vertebral artery were believed to be quite rare. In recent years, because vascular disorders have been studied more thoroughly by three dimensional-computed tomography (3D-CT), angiographically and pathologically, these aneurysms are being reported with more frequency. METHODS: Among the 45 patients diagnosed to have aneurysms arising from the vertebral artery or its branches over a 20-year period, 16 had dissecting aneurysms. The authors present their therapeutic strategy for these patients. Surgery was performed in the 16 patients, the most common technique being clip-occlusion or trapping of the parent artery wherever feasible, in an attempt to optimize cerebral blood flow. The dissecting aneurysms of the vertebral artery were classified into two groups for the purpose of determining a therapeutic approach, namely unilateral and circumferential groups. In the unilateral group, the dissection seemed to involve only on one side of the vessel according to the conventional cerebral angiogram. These patients underwent surgical reconstruction of the vertebral artery by direct clipping. In the circumferential group, the dissection was all around the artery. Proximal clipping or trapping was performed in this group. RESULTS: In six out of eight patients with unilateral dissecting aneurysms, vascular reconstruction was possible by direct clipping. Of these six patients, the surgical outcome was considered excellent in four, fair in one, and one patient died of cardiac failure after 12 days as his preoperative morbid condition remained the same after surgery. Two other patients with unilateral dissecting aneurysms were treated with trapping technique and the surgical outcome was excellent in one patient and good in the other patient. Both patients resumed a normal social life. In five out of eight patients with circumferential dissecting aneurysms, trapping or proximal clipping was performed and the surgical outcome was excellent in two patients, good in one and fair in one patient. One patient with preoperative brain stem infarction died of aspiration pneumonitis after 8 months. Two patients who were noted to have an increase in the size of aneurysm during follow-up angiography underwent a craniotomy with clipping and wrapping of the aneurysm. There was a favorable surgical outcome in both patients. The remaining three patients had Grade IV subarachnoid hemorrhage (SAH) prior to surgery and at autopsy a disturbed vascular wall was detected. CONCLUSION: The authors' experience suggests that when surgically feasible, direct clipping is an effective alternative approach in the treatment of dissecting aneurysms of the vertebral artery in which blood flow in the parent artery is to be preserved.

Adult↗

PubMed1997

Operation on high-lying basilar bifurcation aneurysms.

BACKGROUND: The surgical approach to basilar bifurcation aneurysms is a complicated procedure, especially with those located high in the interpeduncular cistern. We have developed a surgical approach to these aneurysms involving only a small anterior temporal craniotomy and detachment of the zygomatic arch. METHODS: The skin incision is placed 5 mm below the inferior border of the zygomatic arch and 5 mm anterior to the tragus, extending on towards the eyebrow but well within the hairline. The zygomatic arch is detached on either side followed by a small temporal craniotomy exposing the anterior temporal lobe. The temporal lobe is retracted and the internal carotid artery, posterior cerebral artery, posterior communicating artery, and inferior aspect of the optic chiasma are exposed. RESULTS: We have performed a transzygomatic anterior subtemporal approach in 12 patients with high-lying basilar bifurcation aneurysm. Eight patients demonstrated a good recovery as per the Glasgow outcome scale and four patients had a moderate disability that correlated with a poor WFNS grade preoperatively. One patient had an oculomotor palsy and another experienced a small infarction postoperatively. CONCLUSIONS: This approach is a suitable procedure for high-lying basilar bifurcation aneurysms in the interpeduncular cistern and 1.2 cm above the clinoid process.

Aged↗