Recycling air conditioner-generated condensate water for microalgal biomass production and carbon dioxide sequestration.

Air conditioners alleviate the discomfort of human beings from heat waves that are consequences of climate change caused by anthropogenic activities. With each passing year, the effects of global warming worsen, increasing the growth of air conditioning industry. Air conditioning units produce substantial amounts of non-nutritive and (generally) neglected condensate water and greenhouse gases. Considering this, the study explored the potential of using air conditioner condensate water (ACW) to cultivate Chlorella sorokiniana, producing biomass, and sequestering carbon dioxide (CO2). The maximum biomass production was obtained in the BG11 medium (1.45 g L-1), followed by ACW-50 (1.3 g L-1). Similarly, the highest chlorophyll-a content was observed in the BG11 medium (11 µg mL-1), followed by ACW-50 (9.11 µg mL-1). The ACW-50 cultures proved to be better adapted to physiological stress (Fv/Fm > 0.5) and can be suitable for achieving maximum biomass with adequate lipid, protein, and carbohydrate production. Moreover, C. sorokiniana demonstrated higher lipid and carbohydrate yields in the ACW-50 medium, while biomass production and protein yields were comparable to the BG11 medium. The lipid, protein, and carbohydrate productivity were 23.43, 32.9, and 23.19 mg L-1 d-1, respectively for ACW-50. Estimation of carbon capture potential through this approach equals to 9.5% of the total emissions which is an added advantage The results indicated that ACW could be effectively utilized for microalgae cultivation, reducing the reliance on freshwater for large-scale microalgal biomass production and reduce the carbon footprints of the air conditioning industry.

BODIPY staining, an alternative to the Nile Red fluorescence method for the evaluation of intracellular lipids in microalgae.

In order to develop feasible production processes for microalgal biodiesel, the isolation of high neutral lipid producing microalgae is crucial. Since the established Nile Red (NR) method for detection of intracellular lipids has been successful only for some microalgae, a more broadly applicable detection method would be desirable. Therefore, BODIPY 505/515, a lipophilic bright green fluorescent dye was tested for detection of intracellular lipids in Chlorella vulgaris, Dunaliella primolecta and Chaetoceros calcitrans. An optimum concentration of 0.067 µg ml(-1) was determined for lipid staining in the microalgae. Compared to NR, BODIPY 505/515 was more effective in staining microalgae and showed resistance to photobleaching, maintaining its fluorescence longer than 30 min.

Comparison of gallium-67-citrate and thallium-201 scintigraphy in peripheral and intrathoracic lymphoma.

UNLABELLED: We performed this study in an attempt to reconcile the differences with respect to 67Ga uptake as a function of tumor grade and type in the literature, as well as to determine the sensitivity of 201Tl uptake in both Hodgkin's and non-Hodgkin's lymphoma. METHODS: Thirty-six (9 with low-grade lymphoma, 11 with intermediate-grade lymphoma, 4 with high-grade lymphoma and 12 with Hodgkin's lymphoma) patients underwent both 67Ga and 201Tl scintigraphy. Biopsies were done on all patients. A semiquantitative rating system was used to make statistical comparisons for thallium versus gallium in all lymphoma subgroups, as well as comparisons of thallium and gallium to themselves in all subgroups. RESULTS: Patient sensitivity was only 56% and site sensitivity was 32% in patients with low-grade lymphoma. Conversely, 201Tl sensitivity was 100%, respectively, for patients and sites. The difference between 201Tl and 67Ga sensitivity in patients with low-grade lymphoma on a site basis was statistically significant. When compared to itself in lymphoma subgroups, 201Tl was found to be statistically more avid for low-grade lymphoma than for intermediate, high or Hodgkin's lymphoma. Gallium-67 sensitivity for low-grade lymphoma was significantly less than for Hodgkin's and intermediate grade lymphomas. No significant differences were found when 201Tl and 67Ga were compared in the intermediate, high or Hodgkin's lymphoma groups. CONCLUSION: Thallium-201 demonstrates significantly greater tumor avidity in the low-grade lymphoma group compared to 67Ga citrate. Gallium-67-citrate appears relatively nonavid for low-grade lymphoma compared to 201Tl and is statistically inferior in detecting low-grade lymphoma in comparison to its ability to detect intermediate or high-grade lymphomas. Gallium-67-citrate should not be considered dependable in evaluating patients with low-grade lymphoma. Neither 201Tl or 67Ga is dependable in the evaluation of low-grade lymphoma within the abdomen, since gallium avidity for low-grade lymphoma is low and gastrointestinal excretion of 201Tl is poorly controlled.

Thallium scintigraphy in the evaluation of mass abnormalities of the breast.

Palpable mass abnormalities of the breast are often difficult to evaluate mammographically, especially in patients with fibrocystic change and dense breasts. The current study evaluates 201TI scintigraphy as a potential test in detecting malignancy and in differentiating malignant from benign masses. Eighty-one female patients underwent thallium scintigraphy of the breast because of palpable breast masses. An additional 30 females with no palpable breast abnormalities were also studied using 201TI. Of 44 patients with palpable breast carcinomas, 42 carcinomas (96%) were detected using 201TI scintigraphy. Three of three patients had other primary breast malignancies that were also detected. In contrast, 19 patients with palpable breast abnormalities shown on biopsy to be benign fibrocystic disease processes were not detectable on thallium studies. Of two patients with fat necrosis, none were detectable. Three of 13 patients had adenomas of the breast (23%) that were detected. The three detectable adenomas were all highly cellular. The smallest detectable carcinoma was an adenocarcinoma measuring 1.3 x 1.1 x 0.9 cm. Thallium-201 scintigraphy of palpable breast lesions is an effective test for evaluation of palpable masses. Sensitivity for detection of malignant masses greater than 1.5 cm is high. Highly cellular adenomas, however, may demonstrate significant 201TI uptake. Benign fibrocystic disease is not detectable with thallium scintigraphy. Thallium scintigraphy of breast lesions is an effective means of differentiating benign from malignant lesions.

Thallium-201 scintigraphy in differentiated thyroid cancer: comparison with radioiodine scintigraphy and serum thyroglobulin determinations.

The role of thallium-201 (201TI) scintigraphy in the follow-up evaluation of differentiated thyroid carcinoma (DTC) is controversial. Desirable characteristics of 201TI scintigraphy including the potential for no thyroid hormone withdrawal, immediate imaging postinjection, and low radiation burden relative to iodine-131 (131I) suggests it is logistically superior to 131I scintigraphy. Fifty-two patients with DTC were evaluated with 201TI and 131I neck and chest images, and serum thyroglobulin measurements. In post-thyroidectomy and pre-131I ablation therapy patients, very little 201TI accumulation was noted within the thyroid bed, with discordantly increased 131I activity and normal serum thyroglobulin measurements. Twenty-nine percent of patients evaluated after 131I ablative therapy had elevated serum thyroglobulin levels and localized neck and chest abnormalities on 201TI scan that were not seen on 131I studies. Our data suggest that 201TI is more sensitive than 131I diagnostic (5 mCi) studies for detection of DTC, while 131I is more sensitive in detecting normal residual thyroid tissue postoperatively.

Thallium-201 scintigraphy in bone sarcoma: comparison with gallium-67 and technetium-MDP in the evaluation of chemotherapeutic response.

This study attempts to characterize thallium-201 (201TI) uptake in patients with bone and soft-tissue sarcoma and to compare these findings with gallium-67 (67Ga) and bone scintigraphy with emphasis on evaluating tumor viability before and after chemotherapy. Thirty-eight patients with surgically-proven sarcomas were evaluated. All patients had gallium and thallium studies. Nineteen patients underwent pre- and post-chemotherapy thallium and evaluation. Seven patients also had technetium-99m-MDP (99mTc-MDP) bone scintigraphy comparisons. Pathologic changes pre- and postchemotherapy were graded on the basis of %tumor necrosis as defined histologically. Scintigraphic comparisons demonstrated a high degree of correlation with 201TI and poor correlation with 99mTc-MDP. Thallium-201 was superior to 99mTc-MDP and 67Ga in predicting tumor response to chemotherapy as determined by %tumor necrosis determined histologically. Gallium was superior to Tc-MDP in predicting response to chemotherapy. However, both 67Ga and 99mTc-MDP appear to be affected by factors other than tumor activity.

False-positive iodine-131 body scan caused by a large renal cyst.

Focal I-131 accumulation is generally a reliable indicator of functioning thyroid tissue or a differentiated thyroid cancer metastasis. Normal accumulation of activity may be seen in areas such as the intestinal tract, liver, and salivary glands. This report describes a patient with significant accumulation of I-131 in the right upper quadrant of the abdomen. The abnormality, first thought to represent metastatic thyroid carcinoma, was subsequently proven to be accumulation within a large renal cyst.

Regional comparison of technetium-99m DTPA aerosol and radioactive gas ventilation (xenon and krypton) studies in patients with suspected pulmonary embolism.

The regional distribution of [99mTc]DTPA aerosol was compared with that of 133Xe (n = 30) and krypton (n = 24) in a group of patients with suspected pulmonary embolism. All patients had an aerosol study using a recently available commercial generator system, a ventilation study with one of the gases, and perfusion imaging. Regional information was assessed visually on xenon, krypton, and aerosol studies independently by considering each lung as three equal-sized zones. In addition, gas ventilation findings peripheral to regions of aerosol turbulence ("hot spots") were evaluated. Only 64% of the zones were in complete agreement on xenon and aerosol. Most of the discordance between xenon and aerosol was accounted for by minor degrees of 133Xe washout retention in zones that appeared normal in the aerosol study. An agreement rate of 85% was noted between 81mKr and aerosol regionally. The regions of discordance between aerosol and gas studies, however, usually were associated with unimpressive perfusion defects that did not change the scintigraphic probability for pulmonary embolism in any patient. Regarding zones of aerosol hyperdeposition, 76% had associated washout abnormalities on xenon; however, there was no correlation between the presence of these abnormalities or perfusion abnormalities. The results confirm the high sensitivity of 133Xe washout imaging, but suggest that radioaerosol imaging will detect most parenchymal abnormalities associated with perfusion defects of significance.

Evaluation of low-dose radioiodine ablation therapy in postsurgical thyroid cancer patients.

Nineteen patients with differentiated thyroid carcinoma were given low dose (30 mCi) radioiodine therapy for the ablation of residual thyroid tissue following total thyroidectomy. Using 5- to 10-mCi diagnostic I-131 scans, ablation was achieved in two of 19 patients following the first low dose and three of 12 patients following the second low-dose therapy. The ablation response was 53% (ten of 19) following one large dose (100 mCi) in another concurrent group of 19 patients. The ablation response following the first low dose when compared with the first high-dose therapy was significantly lower (P = 0.015). The combined ablation response following first and second low doses (five of 14) when compared to a single large dose was not significantly different (P = 0.534). The use of low-dose-I-131 therapy, although not as effective as large dose therapy, may be warranted in patients resistant to entering the hospital for therapy. However, ablation as defined by a five- to ten-mCi I-131 scan can be expected to occur in only one third of the patients after two attempts at ablation, while a single 100-mCi regimen can be successful in achieving ablation in over one half of the patients after the first attempt.

Treatment rationale in thyroid carcinoma. Effect of scan dose.

The authors have previously shown that the definition of ablation of thyroid tissue in patients treated with thyroidectomy and radioiodine (I-131) for thyroid carcinoma depends upon the dose of I-131 used to scan the patient. The therapeutic response to I-131 therapy was evaluated in a group of ten differentiated thyroid cancer patients who had a negative 2-mCi (-2 mCi) diagnostic study, but had a positive 10-mCi (+10 mCi) diagnostic study (group 1) during their follow-up evaluation. These results were compared to another group of ten differentiated thyroid cancer patients who received I-131 ablation therapy based on a positive 2-mCi (+2 mCi) I-131 scan (group 2). Six patients in group 1 and eight in group 2 had improvement or ablation of residual tissue based on the 10-mCi scan following therapy. The difference in response between the two groups was not statistically significant (P = 0.63) by two-tailed Fisher's exact test, indicating that even patients with -2-mCi, but +10-mCi scans may respond to I-131 therapy. Whether the large dose therapy makes any impact on the clinical outcome has not been answered by this study.

Postperfusion xenon-133 ventilation scintigraphy with a narrow window.

Xenon-133 postperfusion lung scintigraphy using 10% windows was compared with standard posterior preperfusion 133Xe ventilation scanning in 33 patients. The postperfusion 133Xe study identified all major defects and washout abnormalities. In five patients, the assessment of match or mismatch of defects was improved because of optimal positioning of the postperfusion ventilation study. Computer subtraction of background technetium-99m macroaggregated albumin activity improved detection of mild washout abnormalities in eight patients but did not change the diagnostic category in any case. Postperfusion ventilation scanning using 10% windows (with or without background computer subtraction) is an alternative to preperfusion ventilation scanning for major V/Q abnormalities.

Correlation of thyroglobulin measurements and radioiodine scans in the follow-up of patients with differentiated thyroid cancer.

Correlation of radioiodine (131I) scans and serum thyroglobulin (Tg) concentrations were performed in the follow-up of 85 differentiated thyroid cancer patients who had undergone total thyroidectomy. Tg results were also compared with the control group of 33 thyroidectomized patients with no evidence of thyroid carcinoma and normal values for Tg established. Excellent correlation between Tg and scans was noted in patients with scan evidence of metastasis distant from the neck. Poor correlation was present in patients with scan evidence of local neck metastasis only, thyroid bed activity, and those with mediastinal activity. In addition, in 8% of the patients, the Tg assay could not be performed because of interfering antibodies. The conclusion is that elevated Tg concentration is a good indicator of metastasis outside of the neck as detected by 131I scans. Caution should be used when Tg alone is used in evaluating local neck metastasis demonstrated on scans. The significance of mediastinal activity warrants further investigation.

Tc-99m-DTPA aerosol and radioactive gases compared as adjuncts to perfusion scintigraphy in patients with suspected pulmonary embolism.

To evaluate the clinical utility of improved methods for radioaerosol inhalation imaging, we obtained preperfusion radioaerosol images in 107 patients (mean age = 62 years), who were referred for evaluation of suspected pulmonary embolism (PE). For each patient, we compared six-view aerosol images with accompanying perfusion scans and chest radiographs and with Xenon-133 (Xe-133) or Krypton-81m (Kr-81m) studies. Four observers at four different institutions independently evaluated aerosol-perfusion and gas-perfusion pairs, classifying the probability of PE as low, high, or indeterminate. The radioaerosol images were good to excellent in quality; excessive central deposition of activity was infrequent and did not interfere with image interpretation. The aerosol-perfusion studies showed 86% agreement with Xe-133 perfusion interpretations (n = 299) and 80% agreement with Kr-81m perfusion interpretations (n = 99). These rates of agreement were comparable with those of intraobserver agreement for gas-to-gas and aerosol-to-aerosol comparisons, and higher than interobserver agreement rates. In a limited number (n = 9) of angiographically documented cases, aerosol-perfusion and gas-perfusion studies provided accurate and equivalent diagnoses. The results suggest that radioaerosol inhalation studies, performed with improved nebulizers, are diagnostically equivalent to ventilation imaging as an adjunct to perfusion scintigraphy in evaluating patients with suspected PE.

Scintigraphy of gastrointestinal hemorrhage: superiority of 99mTc red blood cells over 99mTc sulfur colloid.

The relative efficacy of 99mTc sulfur colloid and in vitro-labeled 99mTc red blood cells in detecting and localizing gastrointestinal hemorrhage was evaluated in a prospective tandem study of 100 patients referred for suspicion of gastrointestinal tract hemorrhage. Thirty-eight true-positive scintigrams were obtained with 99mTc red blood cells, whereas 99mTc sulfur colloid detected only five sites of hemorrhage. Scintigraphic findings were corroborated by clinical, endoscopic, arteriographic, and surgical findings. 99mTc red blood cells were clearly superior, with a sensitivity of 93%, specificity of 95%, and overall accuracy of 94% in detecting and localizing gastrointestinal hemorrhage.

Cholescintigraphy in acute acalculous cholecystitis.

Acute acalculous cholecystitis is a relatively rare but potentially lethal condition if not treated promptly. Since stones are not present, diagnostic procedures such as ultrasound or other radiological procedures are frequently not helpful. Tc-99m iminodiacetic acid scan results were analyzed in 11 proven cases of acute acalculous cholecystitis. All had positive tests with nonvisualization of the gallbladder giving a sensitivity of 100%. Tc-99m iminodiacetic acid cholescintigraphy is a highly reliable test and is easily performed even in acutely ill patients and should be the test of choice in all patients predisposed to and suspected of acute acalculous cholecystitis.

Gallium scintigraphy in bronchogenic carcinoma. The effect of tumor location on sensitivity and specificity.

Fifty-one patients with primary lung cancer were evaluated using 67Ga citrate scintigraphy with respect to detection of peripheral primary, hilar metastasis, and mediastinal metastasis. The results demonstrated the necessity for an understanding of the criteria used in considering the gallium scintigram as either positive or negative, as well as the instrumentation employed in performing the test before any meaningful sensitivity and specificity figures can be derived within a given institution. Only with this understanding can actual strategy for instituting invasive procedures be achieved.

Acute gangrenous cholecystitis: radionuclide diagnosis.

Radionuclide hepatobiliary imaging is a useful procedure for the diagnosis of acute cholecystitis. Visualization of the gallbladder essentially rules out acute cholecystitis. Nonvisualization suggests acute cholecystitis but may also be associated with chronic gallbladder disease or other conditions. We recently observed five patients in whom a rim of increased parenchymal liver activity was seen adjacent to the gallbladder fossa. All five patients had acute gangrenous cholecystitis. The rim of increased activity appears to be a useful secondary sign of acute cholecystitis.