Coexistence of phylloides tumour and invasive ductal cancer in the breast.

Phylloides tumor in the breast is a rare fibroepithelial tumor, which is often seen in young adult women. Phylloides tumor of the breast accounts for about 1% of all breast tumors and approximately 3% of all fibroepithelial tumors. Pre-operative diagnosis is difficult. Since there aren't any specific mammography and ultrasound findings, they cannot be distinguished from fibroadenomas through these imaging methods and are mostly followed up as if they are fibroadenomas. Patients often present with the complaint of a mass that has been present for a long time and had started to grow suddenly. The primary preferred approach for treatment is wide local excision with negative surgical margins. Coexistence of invasive ductal carcinoma with phylloides tumor in the same breast is a very rare occurrence. We present in this article, a 42-year-old female patient with an invasive ductal carcinoma inside a phylloides tumor in the same breast.

Clinical and microbiological efficacy of tigecycline for complicated skin-soft-tissue and intra-abdominal infections in a Turkish university hospital.

OBJECTIVE: Tigecycline, a new glycylcycline antimicrobial agent, is indicated for the treatment of complicated skin structure infection (cSSTI), intra-abdominal infection (cIAI) and community acquired pneumonia. We aimed to evaluate the clinical and microbiological data together about tigecycline therapy. METHODS: Patients with cIAIs and cSSTIs were included in a prospective, observational follow-up. Patient follow-up forms were developed and clinical and microbiological data were recorded. RESULTS: Of the 107 patients, 67 had cSSTIs, 40 had cIAIs. Tigecycline was used empirically in 37.5% of cIAIs and in 50.7% of cSSTIs. In 85.0% of the patients with cIAI and in 73.1% of the patients with cSSTI, clinical and/or microbiological response could be achieved. A drug change was made in 26.9% and 7.5% of the patients with cSSTI and cIAI respectively. Superinfection was detected in 14.9% of the cSSTI and 7.5% of the cIAI patients. CONCLUSION: As a result, tigecycline can be safely used in the treatment of different infections. Compared with cSSTIs, the treatment response is better and the duration of treatment is shorter in cIAIs. However, MIC value must be determined at any rate if tigecycline is to be used in the treatment of Acinetobacter (MDR Acinetobacter, in particular) infections. Clinical cure and microbiological eradication rate of tigecycline therapy changes according to different clinical diagnosis and microorganism.

The relationship between thorax computed tomography findings and prognosis in patients diagnosed with COVID-19.

OBJECTIVE: This study aimed to demonstrate the relationship between thorax computed tomography (CT) findings at the time of admission and prognosis using a semiquantitative CT severity scoring system in patients diagnosed with coronavirus disease 2019 (COVID-19) who tested positive for reverse transcriptase polymerase chain reaction (RT-PCR). PATIENTS AND METHODS: A total of 305 patients aged 18 years and older who were diagnosed with COVID-19 confirmed by RT-PCR and underwent thorax CT at the time of admission, were included in the study between March and July 2020. The demographic data of the patients, their presenting complaints at the time of admission, RT-PCR results, and thorax CT images were scanned retrospectively from electronic medical records. Lesions on thorax CT were evaluated for the presence of ground glass opacity, consolidation, and septal thickening and scoring. RESULTS: No significant relationship was found between mortality and CT score or other parameters. A significant relationship was found between admission to the intensive care unit and CT scoring (p=0.014), aortic diameter (p=0.032), chronic pulmonary disease (p=0.004), halo sign (p=0.031), mortality (p<0.001), fever (p=0.038), and dyspnea (p=0.031). A statistically significant difference was detected in the score parameter between discharged patients and intensive care unit patients who survived and those who died (p<0.001). In the parameter of the number of lobes, a statistically significant difference was found only between discharged patients and intensive care unit patients who survived (p=0.016). CONCLUSIONS: Thorax CT is an advisor for early diagnosis, treatment, and prognosis assessment of the disease. Semiquantitative CT severity scoring can provide valuable information about the prognosis of the patient.

Percutaneous US-guided needle biopsies of solid renal masses.

Our objective was to examine the variables affecting diagnostic yield and complications in percutaneous ultrasonography-guided needle biopsies of solid renal masses. Percutaneous ultrasonography-guided needle biopsy of solid renal masses was performed in 172 patients with either large size (18G) cutting needles or small size (20G) aspiration needles. Retrospectively, 120 patients with diagnosis by percutaneous biopsy and follow-up data were included in this series. Age, gender, side, locations in kidneys, necrosis, calcification, maximum size, needle groups due to needle size and type (either 18G cutting needles or 20G aspiration needles), and needle pass were selected as variables. Their role was investigated in diagnostic yield. Two needle groups were divided and compared for diagnostic yield and safety. Also, change in treatment was evaluated. The mean maximum size of the masses was 8.8±4.9 cm. The only predictor affecting accuracy was side of kidney (p=0.002). Among patients, 15 (12.5%) and 105 (87.5%) had benign and malignant solid masses, respectively. Small and large needle groups did not differ in accuracy, 80.3% vs. 87.1% (p=1.000). Technical success was detected as 100%. No major complications neither tumor seeding was seen. Percutaneous ultrasonography-guided needle biopsy of solid renal masses is effective and safe method with large size cutting needles and small aspiration needles. Change in clinical management was significant at 63.3% rate. Diagnostic yield was low in left kidney relating to right kidney, 69.4 vs. 93.1, while upper lobe location did not lead to significant false result. Repeat biopsies can be taken under CT guidance after nondiagnostic diagnosis in solid tumors of left kidney. All the needles including large cutting type were found safe.

Fine-needle aspiration biopsy of cervical lymph nodes: factors in predicting malignant diagnosis.

The objective of the study was to determine the predicting factors in malignant diagnosis in ultrasonography guided fine-needle aspiration biopsy of cervical lymph nodes. Design is retrospective follow-up study. Ultrasonography guided fine-needle aspiration biopsies of cervical lymph nodes were performed in 290 patients. The mean age was 45.5 ± 14.4 years (range; 15-85). 207 (71.4%) and 83 (28.6%) were women and men, respectively. Cytopathologist was not present in any biopsy procedure. Factors in predicting malignancy were age, gender, presence of primary malignancy, localization (Level 1-6), hypoechogenicity with loss of echogenic hilum, microcalcification, cystic feature, minimum and maximum sizes, and index value (minimum size/maximum size). Factors were analyzed by univariate and multivariable tests. The mean minimum size and index value of the lymph nodes were 10.4 ± 5.5 mm and 0.58 ± 0.18, respectively. Age, gender, microcalcification, cystic feature, minimum size, and index value were poor predictors in malignancy. Predictors were presence of primary malignancy (p-< 0.001), the level of localization (p=0.001), and hypoechogenicity (p-< 0.001)- in malignancy. Microcalcification and cystic parts were specific US findings of metastasis of thyroid carcinoma; nevertheless cystic parts were seen more specific finding in the other malignancies. Malignant lymph nodes were often found in the presence of primary malignancy, mid neck and lower neck localizations as Level 3-6, and markedly hypoechoic lymph nodes. In 131 patients with a primary thyroid carcinoma, the predictors for malignancy were localization where the most often regions were Level 3, 4, and 6 and hypoechogenicity. Malignancy rate was relatively low in patients with thyroid malignancy than those with non thyroid malignancies in Level 5. Level 6 was the most difficult area for biopsy due to postoperative changes. Microcalcification was specific only in thyroid carcinoma, whereas cystic parts were more specific in the other malignancies

Imaging findings and clinical features of patients with multiple myeloma with the prognostic effect of bone marrow focal and diffuse infiltration patterns on spine MRI.

AIM: Aim of this study was to evaluate the prognostic effect of the magnetic resonance imaging (MRI) infiltration type as diffuse or focal patterns on spine magnetic resonance imaging (MRI), as well as other imaging and clinical features of patients with multiple myeloma. METHODS: A retrospective analysis of 35 patients with multiple myeloma was performed in this study. Patients were mean of 56.5 ± 12.4 year old, male/female ratio=1.3. Patients were at stage 2 and one at stage 3. Skeletal surveys were obtained in all patients, additionally bone scintigraphy (N.=25), CT (N.=22), and spine MRI (N.=16) were conducted. On imaging, lesion number, size and distribution and characteristics were assessed. On MRI, bone marrow involvements were assessed as focal and diffuse patterns (mild, moderate, and severe). All patients were followed-up with MRI for a median of 8.5 months (range, 1-105). Statistical analysis for bone marrow infiltration on MRI was performed using Kaplan-Meier survival test. RESULTS: Patients with diffuse infiltration pattern on MRI survived as median 13.0 months (range, 1-105), whereas cases with only focal pattern survived as median 3.5 months (range, 1-27). There was no difference between these groups (P=0.071). The disease-free survivals were not different, either (P=0.118). Scintigraphy, CT, and MRI detected more lesions in flat bones except for cranium where craniography was successful. CONCLUSION: It was not possible to find any further effect of the diffuse MRI infiltration type beyond focal infiltration on overall and disease-free survivals. Among typical findings of the radiography, spherical, punched-out lesions were seen, but lesion uniformity was not seen.

Peripheral immune response in pulmonary tuberculosis.

Cellular immune response and delayed-type hypersensitivity reactions are considered to play a major role in the immunopathogenesis of pulmonary tuberculosis (PTB). But the exact mechanism is still to be clarified. Th1 cells are mainly involved in cellular immune responses in PTB and provide a normal healing process with minimal or no sequela whereas Th2 cell and CD8(+) T lymphocyte responses may lead to more severe type of disease. In this study, we investigated the peripheral blood immune responses in PTB. The study group consisted of acid fast positive young male soldiers with PTB and a negative HIV serology. The control group included healthy young volunteer male soldiers without a history of PTB. Intracytoplasmic cytokine content of CD8(+) T cells and lymphocytes, including IL-2, IL-4, IL-5, IL-10 and IFN-gamma were determined by flow cytometry, and IL-2, IL-4, IL-5, IL-10, IFN-gamma and TNF-alpha serum levels were measured by cytometric bead array (CBA). No difference was observed between the percentages of T, B, NK cells and HLA-DR expression in both groups, however, the number of CD3(+)HLA-DR(+) activated T cell percentages was higher in PTB group as compared to healthy subjects. IL-2, IL-4, IL-5, IL-10 contents of lymphocytes and IFN-gamma(+)CD8(+) T cells were found to be significantly lower in PTB patients when compared with healthy subjects, and in parallel, serum IL-2, IL-4, IL-5 and TNF-alpha levels were also significantly lower in PTB patients. In conclusion we suggest that, CD8(+) T cells producing both Th1 and Th2 type cytokines, may play important role in the peripheral immune response to mycobacteria.

Natural killer cells in allergic inflammation.

Natural killer (NK) cells are large granular lymphocytes of the innate immune system that exert a potent function against infected and tumor cells. Although NK cells were originally defined by their capacity to lyse target cells and produce interferon-gamma without prior activation, recent studies showed that NK cells also display a potent regulatory function. They are activated or inhibited through the ligation of germline-encoded receptors and are involved in mediating cytotoxicity, producing cytokines and providing costimulation to cells of the adaptive immune system. NK cells play important roles in viral infections, autoimmunity, pregnancy, cancer and bone marrow transplantation, but little is known about the role of NK cells in allergy. Recent developments in the understanding of the role of human NK cells in allergy are overviewed.

A first insight into the genetic diversity and population structure of Mycobacterium tuberculosis in Zonguldak, Turkey.

This study evaluated the molecular epidemiology and biodiversity of Mycobacterium tuberculosis isolates in Zonguldak, Turkey, and investigated the presence and significance of the LAM7-TUR clone by spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis. In total, 128 isolates were tested by spoligotyping; 25 selected isolates representative of the LAM7-TUR clone and similar types were also tested by MIRU-VNTR analysis. In total, 47 distinct patterns were revealed by spoligotyping, represented by 13 clusters containing between two and 28 isolates (94 isolates in total), and 34 unique patterns (a clustering rate of 73%). Using MIRU-VNTR analysis, the clustering relationships revealed by spoligotyping were confirmed. The most common spoligotyping profile was SIT53, followed by SIT41 (LAM7-TUR) and SIT50. The SIT284 clone was another phylogeographically specific clonal complex whose presence in Turkey may be endemic. The LAM7-TUR genotype was highly prevalent in Zonguldak.

Flavonoids, dietary-derived inhibitors of cell proliferation and in vitro angiogenesis.

Consumption of a plant-based diet can prevent the development and progression of chronic diseases associated with extensive neovascularization, including solid malignant tumors. In previous studies, we have shown that the plant-derived isoflavonoid genistein is a potent inhibitor of cell proliferation and in vitro angiogenesis. In the present study, we report that certain structurally related flavonoids are more potent inhibitors than genistein. Indeed, 3-hydroxyflavone, 3',4'-dihydroxyflavone, 2',3'-dihydroxyflavone, fisetin, apigenin, and luteolin inhibited the proliferation of normal and tumor cells, as well as in vitro angiogenesis, at half-maximal concentrations in the low micromolar range. We have previously demonstrated that genistein concentrations in the urine of subjects consuming a plant-based diet is 30-fold higher than in subjects consuming a traditional Western diet. The wider distribution and the more abundant presence of flavonoids in the plant kingdom, together with the present results, suggest that flavonoids may contribute to the preventive effect of a plant-based diet on chronic diseases, including solid tumors.

Usefulness of induced sputum and fibreoptic bronchoscopy specimens in the diagnosis of pulmonary tuberculosis.

We investigated the diagnostic value of induced sputum (IS) and bronchial lavage (BL) specimens in patients with suspected pulmonary tuberculosis who had negative spontaneous sputum specimens or who were unable to produce sputum spontaneously. IS specimens and BL specimens obtained using flexible fibreoptic bronchoscopy from 55 patients were evaluated for the presence of acid-fast bacilli (AFB) and cultured for Mycobacterium tuberculosis. Positive results were found with IS smear in 23 patients, BL smear in 26 patients, and IS or BL culture in 42 patients. Culture of BL specimens had a higher sensitivity than IS or BL smears or culture of IS specimens. The highest sensitivity rate was obtained with a positive BL or IS culture (86%). For early diagnosis (a positive IS or BL smear), the sensitivity was 57%. IS has a higher sensitivity rate than spontaneous sputum for the detection of tuberculosis, and fibreoptic bronchoscopy is useful for the early diagnosis of tuberculosis when AFB are not detected in spontaneous or induced sputum specimens.

Hemolytic activity of dermatophytes species isolated from clinical specimens.

Hemolytic activity was recently reported for several pathogenic fungal species, such as Aspergillus, Candida, Trichophyton, Penicillium and Fusarium. Based on a number of mechanistic and characterization studies, several fungal hemolysins have been proposed as virulence factors. Hemolysins lyse red blood cells resulting in the release of iron, an important growth factor for microbes especially during infection. The requirement of iron in fungal growth is necessary for metabolic processes and as a catalyst for various biochemical processes. Expression of a hemolytic protein with capabilities to lyse red blood cells has also been suggested to provide a survival strategy for fungi during opportunistic infections. The aims of this study were to investigate the hemolytic activities of dermatophytes species isolated from patients with dermatophytosis. Hair, skin and nail samples of patients were examined with direct microscopy using potassium hydroxide and cultivated on Mycobiotic agar and Sabouraud's dextrose agar. To determine hemolytic activities of dermatophytes species, they were subcultured on Columbia Agar with 5% sheep blood and incubated for 7-14 days at 25°C in aerobic conditions. Media which displayed hemolysis were further incubated for 1-5 days at 37°C to increase hemolytic activity. In this study, 66 dermatophytes strains were isolated from clinical specimens and were identified by six different species: 43 (65.1%) Trichophyton rubrum, 7 (10.7%) Trichophyton mentagrophytes, 5 (7.6%) Microsporum canis, 5 (7.6%) Trichophyton tonsurans, 4 (6.0%) Epidermophyton floccosum and 2 (3.0%) Trichophyton violaceum. Twenty-one T. rubrum strains showed incomplete (alpha) hemolysis and nine T. rubrum strains showed complete (beta) hemolysis, whereas hemolysis was absent in 13 T. rubrum strains. Four T. mentagrophytes strains showed complete hemolysis and three T. tonsurans strains showed incomplete hemolysis. However, M. canis, E. floccosum and T. violaceum species had no hemolytic activity. Hemolytic activity is pronounced in dermatophytes and may play an important role as a virulence factor. Hemolysins produced may play an important role in the balance between the host's cellular immunity and the ability of the fungus to diminish the immune response.

Sacroiliac pain and CT-guided steroid injection treatment: high-grade arthritis has an adverse effect on outcomes in long-term follow-up.

OBJECTIVE: The sacroiliac joint (SIJ) is one of the major sources of low back pain that can lead to severe morbidity. Possible SIJ pain requires a thorough evaluation and treatment option. The purpose of this study was to analyze the possible relationships between computed tomography (CT) grading of SIJ arthritis and the effectiveness of intraarticular steroid injection treatment under CT guidance. PATIENTS AND METHODS: A total of 61 patients with SIJ pain who were treated with CT guided intraarticular steroid injection were retrospectively reviewed. Visual analog scale (VAS) scores for pain control were recorded for short-term (day after injection, first week, third week) and long-term (sixth months and final control) follow-up times. SIJ arthritis was graded using CT images according to the New York criteria. Patients were assigned into low-grade (0, 1 and 2) and high-grade (3 and 4) groups. The relationship between arthritis grades and VAS scores in short and long-term follow-ups were statistically analyzed. RESULTS: Mean age and follow-up was 54.8 years (range: 41-68 years) and 27.8 months (range: 24-36 months), respectively. In 40 patients there was low-grade arthritis, while 21 patients were characterized on having high-grade sacroiliac arthritis detected during the radiological evaluation. There was no statistically significant difference between low and high-grade arthritis in regard to short-term VAS scores. On contrary, for long-term VAS scores, there was significant difference between low- and high-grade arthritis. CONCLUSIONS: Steroid injection treatment for SIJ pain is not effective on a long-term basis for patients with high-grade arthritis, and although they have had decreased VAS scores in the short-term, after 2 years of follow-up, their VAS scores significantly increased leading to symptomatic sacroiliac joint pain.

Bacteriological, clinical and epidemiological characteristics of hospital-acquired Acinetobacter baumannii infection in a teaching hospital.

Over an 18 month period, the bacteriological, clinical and epidemiological characteristics of nosocomial Acinetobacter baumannii infections in a teaching hospital were studied. Typing studies were performed on 38 strains isolated from 36 patients. Twenty-two of the strains were isolated during the three outbreaks. Surgery, catheterization, mechanical ventilation, and antibiotic therapy for adult patients and respiratory distress syndrome, mechanical ventilation, and prematurity for paediatric patients were the main risk factors identified. All isolates were resistant to penicillins (except ampicillin-sulbactam), cephalosporins, gentamicin, and aztreonam but susceptible to carbapenems and colistin. Resistance to tobramycin, ciprofloxacin, ampicillin-sulbactam, trimethoprim-sulfamethoxazole, and amikacin was variable. Antibiotyping, arbitrarily-primed polymerase chain reaction (AP-PCR) and the pulse-field gel electrophoresis (PFGE) indicated the epidemiological relationship. The outbreak strains, demonstrated genetic distinction between our three outbreaks and isolates from specific areas in the hospital.

Characterization and lime treatment of olive mill wastewater.

Seventeen olive mill wastewater (OMW) samples were characterized. For characterization of the samples, amount of total, fixed, volatile, suspended, volatile-suspended solids, COD, oil-grease, polyphenol, volatile phenol, nitrogen and reducing sugar were determined. Effects of lime treatment on the waste samples were investigated. Reduction of contents of the samples treated with the lime was described. The effect of the addition of lime on an artificial phenolic mixture was also examined.

A modified automated method for isolation of viable pancreatic islets in laboratory animals.

To achieve successful islet transplantation, a high viability is required. For this reason an automated method including two chambers: one for islets isolation and one for recirculation and collection was developed. Recently, we produced a modified version of this work by building a similar system of glass where marbles were not used for disaggregation, and the pancreatic tissue had to be disrupted mechanically before the digestion phase. By using the reconfigured system, we obtained 260 +/- 20 islets from each Wistar albino rat (weighing 220 to 240 g) pancreas. Islets were observed at 35 minutes after the start of perfusion (closed circuit) and the optimum time to stop the isolation determined to be 40 minutes based upon islets viability. Although the present system is configured for islet isolation from small laboratory animals (rat, mouse), we have also obtained thousands of islets at 25 minutes after treatment of a 0.5-g piece of pig pancreas. Compared to the time-consuming manual method usually used for islet isolation from small laboratory animals, the new technique is economic, easy to use, and does not reduce islets viability.

Effect of human somatotropin hormone on cultured rat islets.

Because growth hormone (GH) improves the insulin secretion capacity of isolated human fetal islets in vitro, we sought to show that it positively influences isolated rat islets. Islets isolated from Wistar albino rats by a modified automated system were cultured in media containing 87% RPMI 1640, 10% FCS, 2% antibiotic-antimycotic, and 1% L-glutamine for 12 +/- 2 days. The cultured islets were divided into two groups: growth hormone negative (Group I) and growth hormone positive (Group II). On the 5th day we observed a decrease in the islet cell counts in both groups (Group I 28% versus Group II 45%). On the 10th day, the decrease continued in the GH-negative group (59%), while the count remained stable in the GH-positive group. The viability of rat islets was determined by fluorescein diacetate (FDA) plus propidium iodide (PI) staining. In comparison to the peripheral green, central orange-red staining pattern of Group I islets upon fluorescent microscopy, Group II showed more compact islets. Cultured islets seemed to be brighter than those without GH in the cultured islets. In conclusion, we observed that 2 weeks of incubation in the presence of GH acts positively on cultured rat islets for both their amount and their viability.

Fine needle aspiration biopsy in hepatic Echinococcus multilocularis.

OBJECTIVE: To determine the fine needle aspiration biopsy (FNAB) findings in hepatic Echinococcus multilocularis. STUDY DESIGN: FNAB and tru-cut liver needle biopsy were applied in 14 hepatic E multilocularis cases. Cytologic smears were stained with May-Grünwald-Giemsa and periodic acid-Schiff (PAS) stain. Tissue sections were stained with hematoxylin-eosin (HE) and PAS stain. RESULTS: In tissue sections, homogeneous, thin, cystic structures of various dimensions strongly stained with PAS. Mucoid material was stained with PAS in the cystic structures. Wide, coagulative necrosis was observed in all cases. In some cases there were foreign body-type giant cells at the periphery of the lesion. In all the cytologic smears there were an intense necrotic ground, PAS-positive hyaline cuticular structures and mucoid globules; in some cases there were foreign body-type giant cells. CONCLUSION: The above cytologic characteristics are basic diagnostic criteria for FNAB of E multilocularis.

The prognostic significance of cervico-vaginal cytology in endometrial cancer.

In patients with endometrial cancer, preoperative identification of certain poor prognostic factors is helpful in planning therapy. To determine the place of cervico-vaginal cytology in this respect, we have studied the relationship between cervico-vaginal cytology and the well-known prognostic factors of endometrial cancer such as grade, myometrial invasion, peritoneal cytology, stage and histological subtype. A hundred and sixty two patients, all of whom underwent surgical therapy in our clinic, were included in this study in order to correlate the cytological results with the pathological findings. Cervico-vaginal cytology was negative in 88 patients (54%), suspicious in 26 patients (16%) and malignant in 48 patients (30%). Twenty four per cent of cases with adenocarcinoma and adenoachantoma, and fifty two per cent of patients with adenosquamous carcinoma, papillary adenocarcinoma and clear cell carcinoma had positive cervicovaginal cytology (p < 0.001). Seventy four per cent of patients with negative cervico-vaginal cytology had grade I tumor, while 5% of patients with negative cytology had grade III tumor. On the other hand, only 9% of patients with positive cervico-vaginal cytology had grade I tumor, while 55% had grade III tumor (p < 0.001). 8% of patients with inner 1/2 myometrial invasion had positive cytology, whereas 51% of patients with 1/2 outer myometrial invasion had malignant cells in their smear (p < 0.001). As for the staging of the endometrial cancer according to FIGO, 19% of patients with Stage I disease had positive cervico-vaginal cytology while 60% of patients in Stage II and 66% of patients in Stage III-IV had positive cytology (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Esterase activity in various Candida species.

The aim of the present study is to ascertain esterase activities of various species of Candida. A total of 125 strains isolated and identified by conventional methods were tested for esterase activity using the Tween 80 opacity test. Our results showed that 58 of 59 strains of Candida albicans, all of the Candida tropicalis strains (n = 38) and all of the Candida guilliermondii strains (n = 3) produced positive results, whereas the remaining Candida species did not. The Tween 80 opacity test is a useful method because it is simple, economical and easy to prepare and interpret.