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Biomedical subjects

A Cittadini

Publications and source records attributed to A Cittadini.

At least 37 records · Page 2Linked to original sources

Anomalous dystroglycan in carcinoma cell lines.

Dystroglycan is a receptor responsible for crucial interactions between extracellular matrix and cytoplasmic space. We provide the first evidence that dystroglycan is truncated. In HC11 normal murine and the 184B5 non-tumorigenic mammary human cell lines, the expected beta-dystroglycan 43 kDa band was found but human breast T47D, BT549, MCF7, colon HT29, HCT116, SW620, prostate DU145 and cervical HeLa cancer cells expressed an anomalous approximately 31 kDa beta-dystroglycan band. alpha-Dystroglycan was udetectable in most of the cell lines in which beta-dystroglycan was found as a approximately 31 kDa species. An anomalous approximately 31 kDa beta-dystroglycan band was also observed in N-methyl-N-nitrosurea-induced primary rat mammary tumours. Reverse transcriptase polymerase chain reaction experiments confirmed the absence of alternative splicing events and/or expression of eventual dystroglycan isoforms. Using protein extraction procedures at low- and high-ionic strength, we demonstrated that both the 43 kDa and approximately 31 kDa beta-dystroglycan bands harbour their transmembrane segment.

Animals↗

Effect of extracellular magnesium on topoisomerase II activity and expression in human leukemia HL-60 cells.

Topoisomerase II (TopoII) is a Mg-dependent enzyme involved in topological modifications of DNA that are crucial to the regulation of cell proliferation and possibly differentiation. To investigate the role of Mg availability in the modulation of TopoII in whole cells, we studied enzyme activity and expression in HL-60 cells grown in the presence of decreasing amounts of extracellular Mg (0.5, 0.03, and 0.01 mM MgSO(4)). In comparison to cells grown in 0.5 mM Mg, cells grown in 0.03 mM Mg exhibited a decrease in TopoII activity, as evidenced by reduced induction of DNA/TopoII cleavable complexes and apoptosis by etoposide and teniposide. Enzyme activity was restored by the readdition of Mg (0.5 and 1.5 mM) in the incubation medium, confirming that this effect was indeed modulated by extracellular Mg. Restriction of Mg to 0.01 mM was associated with a dramatic decrease in TopoII activity resembling that observed in HL-60 cells differentiated by dimethyl sulfoxide treatment. The restriction of Mg, while decreasing enzyme activity, was found to upregulate TopoII protein expression, determined by Western blot analysis. The increase of TopoII protein levels was correlative with the degree of Mg deprivation. Collectively, these results indicate that extracellular levels of Mg may control availability of intracellular Mg, thus affecting the regulation of TopoII activity/expression and downstream processes of cell proliferation and/or differentiation.

Apoptosis↗

Multiple functions of p27(Kip1) and its alterations in tumor cells: a review.

Cyclin-dependent kinases (CDKs), together with cyclins, their regulatory subunits, govern cell-cycle progression in eukaryotic cells. p27(Kip1) is a member of a family of CDK inhibitors (CDIs) that bind to cyclin/CDK complexes and arrest cell division. There is considerable evidence that p27(Kip1) plays an important role in multiple fundamental cellular processes, including cell proliferation, cell differentiation, and apoptosis. Moreover, p27(Kip1) is a putative tumor-suppressor gene that appears to play a critical role in the pathogenesis of several human malignancies and its reduced expression has been shown to correlate with poor prognosis in cancer patients. This study reviews current information on the functions of p27(Kip1), its abnormalities found in human tumors, and the possible clinical implications of these findings with respect to the management of cancer patients.

Animals↗

Echocardiographic assessment of cardiac morphology and function in mutant dwarf rats.

Although the mutant dwarf rat has been proposed as a model of growth hormone (GH) deficiency, few studies have addressed its cardiovascular abnormalities. Therefore, the aim of the present study was to investigate cardiac structure and function in mutant dwarf rats in vivo before and after chronic GH administration, by means of transthoracic Doppler echocardiography. To this purpose, forty 90-day-old female dwarf rats were randomized to receive either GH treatment or placebo. Twenty age-and sex-matched Lewis rats (200-250 g) served as the control group. All rats underwent echocardiograms before receiving any drug and after 3 weeks of therapy. Echocardiographically detected left ventricular mass indexed to tibial length was reduced by 41% in dwarf rats compared to the control group. Such relative cardiac atrophy was also evident at the myocyte level, and was fully reversible after GH therapy. In contrast to the control group, dwarf rats also showed a reduction of left ventricular diastolic volumes normalized to tibial length and impaired cardiac performance as suggested by the reduction of cardiac index, abnormal stress-shortening relations, and a significant elevation of total peripheral vascular resistance. All these abnormalities were reversible upon GH therapy for 3 weeks. In conclusion, GH plays an important role in maintaining a normal cardiac structure and function. Since the observed changes are similar to those seen in GH-deficient men, the mutant dwarf rat represents a faithful animal model of GH deficiency.

Animals↗

Cardiovascular effects of short-term growth hormone hypersecretion.

Many studies have shown that acromegaly has relevant effects on cardiovascular system, but few data are available regarding the effects of short-term acromegaly on heart morphology and function. These data would help to clarify the natural history of acromegalic disease and could provide new insight into the mechanisms of GH action on the human heart. Therefore, we studied by Doppler echocardiography a group of 10 young subjects strictly selected as having short-term (<5 yr) uncomplicated acromegaly. The results of this study have shown that shortterm acromegaly is characterized by significantly increased left ventricular mass (P<0.005), with normal relative wall thickness, associated with Doppler indices of diastolic function in the normal range. Furthermore, stroke index and cardiac index were significantly enhanced in the patient group (P<0.01 and P<0.001, respectively), whereas systemic vascular resistance was significantly reduced (P<0.001). In conclusion, our study shows that short-term acromegaly significantly affects the heart, but, at variance with long-term disease, it is characterized by increased left ventricular mass, with eccentric remodeling and normal diastolic function. Moreover, short-term acromegaly induces a high cardiac output state with reduction of systemic vascular resistance.

Acromegaly↗

The effect of four weeks of supraphysiological growth hormone administration on the insulin-like growth factor axis in women and men. GH-2000 Study Group.

Measurements of serum insulin-like growth factor I (IGF-I) and related markers are routinely used in the diagnosis and treatment of GH deficiency and excess. The validity of these markers for assessment of exogenous GH exposure in healthy adults is, however, unknown. We therefore conducted a double blind, placebo-controlled GH treatment trial in 99 healthy subjects [49 women and 50 men; mean +/- SE age, 25.6+/-0.6 (women)/25.7+/-0.6 yr (men)]. Blood was collected weekly during a 4-week treatment period (days 1-28), and the subjects were subsequently followed for additional 8 weeks (days 29-84). The treatment arms included: I) 0.1 IU/kg x day GH (n = 30; GH 0.1), II) 0.2 IU/kg x day GH (n = 29; GH 0.2), and III) placebo (n = 40). At baseline no gender-specific differences existed, except that the acid-labile subunit (ALS) levels were higher in females. Serum insulin-like growth factor I (IGF-I) levels in males receiving GH increased significantly through day 42 with no significant difference between the 2 doses. The absolute IGF-I response was significantly lower in females, and there was a clear dose-response relationship. ALS levels in males increased through day 30 (P < 0.001). In females ALS levels were only modestly increased on day 28 compared with those in the placebo group (P < 0.02). IGF-binding protein-3 (IGFBP-3) levels in males increased significantly in the GH 0.1 and the GH 0.2 groups on day 30 (P < 0.03), whereas no solid IGFBP-3 increase was detected in females. IGFBP-2 levels decreased insignificantly during GH exposure in both genders. A gender-specific upper normal range for each analyte was arbitrarily defined as 4 SD above the mean level at baseline. On the basis of IGF-I levels alone, GH exposure in the GH 0.2 group was detected in 86% of the males and in 50% of the females on day 21. On day 42 GH exposure was only weakly detectable in males and was not detectable in females. We conclude that 1) males are significantly more responsive than females to exogenous GH; 2) the increase in IGF-I is more robust compared with those in IGFBP-3 and ALS; 3) IGFBP-2 changes very little during GH treatment; and 4) among IGF-related substances, IGF-I is the most specific marker of supraphysiological GH exposure.

Adolescent↗

Growth hormone (GH) effects on bone and collagen turnover in healthy adults and its potential as a marker of GH abuse in sports: a double blind, placebo-controlled study. The GH-2000 Study Group.

The effects of GH on bone remodeling in healthy adults have not been systematically investigated. An analysis of these effects might provide insights into GH physiology and might yield data useful for the detection of GH doping in sports. The aim of this study was to evaluate the effects of GH administration on biochemical markers of bone and collagen turnover in healthy volunteers. Ninety-nine healthy volunteers of both sexes were enrolled in a multicenter, randomized, double blind, placebo-controlled study and assigned to receive either placebo (40 subjects) or recombinant human GH (0.1 IU/kg day in 29 subjects and 0.2 IU/kg x day in 30 subjects). The treatment duration was 28 days, followed by a 56-day wash-out period. The biochemical markers evaluated were the bone formation markers osteocalcin and C-terminal propeptide of type I procollagen, the resorption marker type I collagen telopeptide, and the soft tissue marker procollagen type III. All variables increased on days 21 and 28 in the two active treatment groups vs. levels in both the baseline (P < 0.01) and placebo (P < 0.01) groups. The increment was more pronounced in the 0.2 IU/kg-day group and remained significant on day 84 for procollagen type III (from 0.53 +/- 0.13 to 0.61 +/- 0.14 kU/L; P < 0.02) and osteocalcin (from 12.2 + 2.9 to 14.6 +/- 3.6 UG/L; P < 0.02), whereas levels of C-terminal propeptide of type I procollagen and type I collagen telopeptide declined after day 42 and were no longer significantly above baseline on day 84 (from 3.9 +/- 1.2 to 5.1 +/-1.5 microg/L and from 174 +/- 60 to 173 +/- 53 microg/L, respectively). Gender-related differences were observed in the study; females were less responsive than males to GH administration with respect to procollagen type III and type I collagen telopeptide (P < 0.001). In conclusion, exogenous GH administration affects the biochemical parameters of bone and collagen turnover in a dose- and gender-dependent manner. As GH-induced modifications of most markers, in particular procollagen type III and osteocalcin, persist after GH withdrawal, they may be suitable markers for detecting GH abuse.

Adult↗

8-hydroxy-2'-deoxyguanosine in cervical cells: correlation with grade of dysplasia and human papillomavirus infection.

In this study, the 8-hydroxy-2'-deoxyguanosine (8-OHdG) level was assessed in human cervical cells by an immunoperoxidase method and was related to the presence of human papillomavirus (HPV) infection and precancerous lesions. After optimizing the immunohistochemical method of detecting oxidative DNA damage in whole cells, we have used this technique to estimate the oxidative damage in cervical cells collected during a routine PAP test. The analysis of variance (ANOVA) of the data from human samples showed significant differences in the 8-OHdG content among normal, low-grade and high-grade squamous intraepithelial lesion (SIL, HGSIL and LGSIL, respectively; P < 0.001). In the comparison of the three groups, statistically significant differences were detected between normal SIL and HGSIL (P < 0.001) and between LGSIL and HGSIL (P = 0.003), whereas no statistically significant difference was found between normal SIL and LGSIL (P = 0.1). Grouping observations by HPV status, no significant difference was detected in 8-OHdG levels between HPV(+) and HPV(-) subjects (P = 0.8). The polytomous and proportional odds models, extensions of the logistic regression analysis, showed that the effect of 8-OHdG levels in rising the risk of dysplasia was roughly constant through SIL grades. In conclusion, the immunoperoxidase method, applied to single human cervical cells, provides clear evidence that significant differences exist in 8-OHdG content between normal and dysplastic cells and that oxidative DNA damage might play an important role in cervical carcinogenesis.

8-Hydroxy-2'-Deoxyguanosine↗

Detection by denaturant gradient gel electrophoresis of tumor-specific mutations in biopsies and relative bronchoalveolar lavage fluid from resectable non-small cell lung cancer.

A PCR-denaturant gradient gel electrophoresis (DGGE) method was developed for the detection of p53 and K-ras mutations in primary operable tumors and paired BAL samples of non-small cell lung cancer. Among 36 patients, 9 showed p53 exon V mutations in biopsies and in three paired bronchoalveolar lavage (BAL) specimens with a 33% concordance. Five patients presented p53 exon VI mutations in biopsies and in two paired BALs with a 40% concordance. No mutations were found in p53 exon VII either in biopsies or in paired BAL samples with 100% concordance. Exon VIII mutations were found in six primary tumors and in two BALs with a 33% concordance. Of 36 patients, we detected 7 (19.4%) with K-ras exon I mutations on tumor samples. DGGE analysis of DNA from BAL samples revealed three mutations distributed on K-ras exon I with a 42% overall concordance with respect to tumor tissue. Molecular screening by DGGE of p53-amplified DNA from BAL had cumulative 46.6% sensitivity, 100% specificity, and 77.7% accuracy. DGGE K-ras detection showed 43% sensitivity, 100% specificity, and 88.8% test accuracy. The method proposed demonstrated to be specific, accurate, and at relatively low cost but limited by low sensitivity in detecting the presence of neoplastic cells in patients with resectable non-small cell lung cancer.

Adenocarcinoma↗

Loss of p21Waf1 expression is a strong predictor of reduced survival in primary superficial bladder cancers.

p21Waf1 is a downstream effector of p53 and belongs to the Cip1/Kip1 family of cyclin-dependent kinase inhibitors. Thus, it is a potential tumor suppressor gene and likely plays an important role in tumor development. Moreover, reduced expression of p21Waf1 has been reported to have prognostic value in several human malignancies. In this study, we evaluated the prognostic value of p21Waf1 in bladder cancer compared with other clinicopathological features and with p27Kip1 and p53 expression. A total of 96 superficial (pTa-1) human bladder carcinomas were immunohistochemically stained for p21Waf1 protein expression. Positive p21Waf1 staining (> or =5% positive nuclei) was observed in 68 of the 96 (71%) tumors. p21Waf1 expression was neither associated with tumor stage (P = 0.9) nor with tumor grade (P = 0.18) but was significantly associated with both p53 protein expression (> or =20% positive nuclei; P = 0.007) and with p53 gene mutations (P = 0.017). A significant correlation was also observed between positivity for p21Waf1 and high (>50% positive cells) p27Kip1 expression (P = 0.04). With regard to prognosis, patients whose tumors showed absence of p21Waf1 staining displayed a significantly shorter overall survival (P = 0.01 by log-rank test). However, p21Waf1 expression did not correlate with disease-free survival (P = 0.15 by log-rank test). On a multivariate analysis that also included p53 and p27Kip1 expression, negative p21Waf1 staining was an independent predictor of reduced overall survival (P = 0.004; relative risk, 5.32), stronger than age and tumor stage. These data indicate that expression of p21Waf1 protein strongly correlates with survival and might represent a useful prognostic marker in primary superficial bladder carcinomas.

Adult↗

[Myocardial metabolism of calcium in heart failure: from physiology to new therapeutic perspectives].

Development of heart failure is associated with an impairment of intracellular calcium handling. The precise mechanisms involved are still obscure. When membrane depolarization occurs, a small amount of extracellular calcium enters the intracellular milieu through the L-type channels. Such "trigger" calcium acts on specific receptors of the sarcoplasmic reticulum, that, in turn, according to the so-called calcium entry-calcium release mechanism, allows the release of a larger amount of calcium from the sarcoplasmic reticulum. Removal of calcium from the cytosol is the key event of the diastolic phase. Calcium removal from cytosol occurs through specific membrane pumps. Recent therapeutic approaches involving gene targeting of calcium pumps have yielded promising results. Specifically, increased levels of SERCA 2 in the myocardium have shown to enhance cardiac contractility under normal circumstances and in experimental heart failure. Future research is needed to confirm these findings in human heart failure.

Calcium↗

Cardiovascular abnormalities in transgenic mice with reduced brown fat: an animal model of human obesity.

BACKGROUND: A new model of murine obesity has recently been developed through transgenic ablation of brown adipose tissue that manifests typical metabolic complications of obesity, including insulin resistance and non-insulin-dependent diabetes mellitus. The cardiovascular phenotype has not been defined. METHODS AND RESULTS: Transthoracic echocardiography, aortic catheterization, isolated whole-heart studies, and morphometric histology defined cardiac structure and function in 30 transgenic mice with reduced brown fat and 30 matched wild-type controls. Obesity was indicated by a 77% increase in body weight and was accompanied by elevated systemic pressures (mean aortic blood pressure 85+/-1 versus 66+/-2 mm Hg; P<0.01), left ventricular dilation and hypertrophy (mass/body weight 4.0+/-0.2 versus 2.7+/-0.3 mg/g; P<0.01), and high cardiac output (cardiac index 3.2+/-0.4 versus 2.4+/-0.1 mL x kg(-1) x min(-1); P<0.01). Baseline functional parameters assessed in vitro were not different, but after imposition of zero-flow ischemia, significant relaxation impairment developed in obese mice. Although morphometrically determined myocyte diameters were similar, the percentage of interstitial fibrosis was significantly increased in transgenic mice compared with wild-type controls (7.5+/-2% versus 4. 2+/-0.2%; P<0.01). CONCLUSIONS: Transgenic ablation of brown adipose tissue is associated not only with obesity but also with systemic hypertension, left ventricular hypertrophy with eccentric remodeling and fibrosis, and high cardiac output, a unique constellation of findings strikingly similar to that seen in human obesity. Mice with reduced brown fat may serve as a new model for the cardiovascular morbid complications associated with obesity in humans.

Adipose Tissue, Brown↗

Magnesium in cell proliferation and differentiation.

Compelling evidence shows that magnesium (Mg) content is directly correlated to proliferation in normal cells as Mg stimulates DNA and protein synthesis. Some data have demonstrated that upon mitogenic stimuli normal cell are able to increase their intracellular Mg content, likely by activating Mg influx. Mg deprivation, in turn, induces inhibition of DNA and protein synthesis thus promoting growth arrest. From a mechanistic viewpoint, Mg deprivation may influence cell cycle control by upregulating the cyclin inhibitor p27Kip1 thus influencing cyclin E-dependent kinases. In many neoplastic cells, Mg is higher than in normal counterparts and this high Mg is maintained also against concentration gradient. Moderate vs. severe and acute vs chronic effect of Mg deprivation must be distinguished: severe Mg deprivation causes growth arrest also in tumor cells, while chronic Mg deprivation leads to an "adaptation" of tumor cells both to growth rate and Mg content. In tumor cells deranged Mg content and distribution is likely due to an inhibition of Mg efflux via the Na-Mg antiport. When differentiation process is induced by receptor mediated stimuli such as IFN-alpha and ATP, decrease of cell Mg content accompanies with activation of Mg efflux. Transformed cells may thus display high growth rate also because they retain a large amount of Mg. On their whole, these data strongly suggest that regulation of intracellular Mg availability parallels the molecular control of cell proliferation, and maybe also cell differentiation and death.

Animals↗

Frequent loss of expression of the cyclin-dependent kinase inhibitor p27 in epithelial ovarian cancer.

p27Kip1 is a member of the Cip1/Kip1 family of cyclin-dependent kinase inhibitors and is a potential tumor suppressor gene. Low levels of p27 are associated with poor prognosis in a variety of tumors, including breast, colon, prostate, and lung carcinomas. In the present study, p27 protein expression was investigated by immunohistochemistry and Western blot analysis in a series of 82 epithelial ovarian tumors [16 classified as low malignant potential (LMP) and 66 classified as primary ovarian adenocarcinomas]. Immunohistochemical analysis revealed frequent loss of p27 expression in primary ovarian adenocarcinomas (33%), with respect to LMP tumors (6%; P = 0.0009). In addition to nuclear staining, cytoplasmic localization of p27 was noted in 45 (55%) of 82 cases. p27 levels inversely correlated with cdk2 kinase activity in a representative subset of tumors. When the clinical outcome of the patients was evaluated in relationship to p27 status, we observed a significant correlation between presence of p27 staining and a longer time to progression (P = 0.032 by log-rank test). These data indicate that loss of p27 is a frequent event in ovarian carcinomas as compared with LMP tumors, suggesting that these tumor types may have different pathogenesis. p27 levels may also represent a useful prognostic marker for predicting disease recurrence in primary ovarian carcinomas.

Adenocarcinoma↗

Loss of P27Kip1 expression correlates with tumor grade and with reduced disease-free survival in primary superficial bladder cancers.

p27Kip1 is a member of the Cip1/Kip1 family of cyclin-dependent kinase inhibitors and is a potential tumor suppressor gene. We previously reported a deregulated expression of p27Kip1 in a series of human cancer cell lines and in primary breast and colon cancers. Moreover, p27Kip1 has been reported as an important prognostic factor in primary lung, breast, colon, and prostate cancers. In this study, we evaluated the prognostic value of p27Kip1 in a series of 96 superficial (pTa-1) human bladder carcinomas. High (>50% positive cells), moderate (25-50%), and low (<25%) p27Kip1 staining was observed in 39 (41%), 19 (20%), and 38 (39%) of the 96 primary superficial bladder cancers, respectively. No significant association was found between the expression level of p27Kip1 and tumor stage. Decreased p27Kip1 staining correlated with higher tumor grade (P = 0.001). Interestingly, a significant association was observed between increased expression of p27Kip1 and positivity for p53 (>20% positive cells; P < 0.001). A significant correlation was also observed between low expression of p27Kip1 and decreased disease-free survival (P = 0.0003 by log-rank test) and overall survival (P = 0.01 by log-rank test). Furthermore, on multivariate analysis, low p27Kip1 protein expression was an independent predictor of reduced disease-free survival (P = 0.018; relative risk = 1.95) second only to tumor stage. These data indicate that p27Kip1 protein is frequently expressed at low level in poorly differentiated tumors and suggest that this protein might represent a useful prognostic marker for disease recurrence and overall survival in superficial bladder carcinomas.

Adult↗

Magnesium depletion causes growth inhibition, reduced expression of cyclin D1, and increased expression of P27Kip1 in normal but not in transformed mammary epithelial cells.

In this study, we have evaluated the effects of extracellular magnesium restriction on the growth and cell cycle parameters of normal (HC11) and transformed (MCF-7) breast epithelial cell lines. Cells were incubated in medium with different concentrations of Mg2+ (from 0.5 to 0 mM) and the growth rates were determined by [3H]-thymidine incorporation and cell counting. The growth of the HC11 cells was drastically inhibited by Mg2+ depletion whereas the MCF-7 cells were only slightly inhibited (about 50% and 15%, respectively, after incubation in 0.05 mM Mg for 48 h). Cell cycle analyses showed a decrease in the percentage of cells in the S phase when both cell lines were incubated at low Mg2+ concentration. However, while the percentage of cells in both the G0/G1 and G2/M phases was increased in the HC11 cells, only the percentage of cells in the G2/M phase was increased in the MCF-7 cell line. Extracellular magnesium depletion was associated with increased expression of the cyclin-dependent kinase inhibitor p27Kip1 and decreased expression of cyclin D1 in the HC11 but not in the MCF-7 cells. We also demonstrated that Mg2+ depletion does not inhibit kinase activities in the normal HC11 cells and that Mg2+-restricted HC11 cells are still responsive to the epidermal growth factor (EGF)- and insulin-mediated stimulation of cell growth. These data suggest that normal but not transformed mammary epithelial cells are inhibited by extracellular Mg2+ restriction and that this effect might be mediated by changes in the levels of expression of both cyclin D1 and p27Kip1.

Animals↗

Polycyclic aromatic hydrocarbon-DNA adducts in cervical smears of smokers and nonsmokers.

OBJECTIVES: The aim of this study was to detect polycyclic aromatic hydrocarbon-DNA (PAH-DNA) adducts in single cervical cells collected during a routine Papanicolaou smear and to relate this carcinogen exposure dose marker to smoking habit. METHODS: An immunohistochemical assay, using a polyclonal antiserum raised against benzo[a]pyrene diol epoxide-DNA adducts, was performed to evaluate PAH-DNA adducts in cervical cells collected from 16 volunteers who smoked at least 20 cigarettes/day and 16 nonsmokers. RESULTS: The mean adduct level, determined as relative staining intensity by an optical density image analyzer, was significantly higher in smokers compared to nonsmokers (AOD x 1000 +/- SD = 98 +/- 32 and 73 +/- 25, respectively) (P = 0.04). CONCLUSIONS: These results demonstrate that this immunohistochemical assay, much simpler than other methodologies used to evaluate PAH-DNA adducts in cervical tissue, is sufficiently sensitive for quantitative adduct evaluation in single epithelial cervical cells, as already verified for other exfoliated material. This work thus confirms that tobacco smoke is a risk factor for genotoxic damage generation in cervical cells and indicates a procedure likely adaptable to a large population screening.

Adult↗