Genetic Causes and Genomic Consequences of Breakdown of Distyly in Linum trigynum.

Distyly is an iconic floral polymorphism governed by a supergene, which promotes efficient pollen transfer and outcrossing through reciprocal differences in the position of sexual organs in flowers, often coupled with heteromorphic self-incompatibility. Distyly has evolved convergently in multiple flowering plant lineages, but has also broken down repeatedly, often resulting in homostylous, self-compatible populations with elevated rates of self-fertilization. Here, we aimed to study the genetic causes and genomic consequences of the shift to homostyly in Linum trigynum, which is closely related to distylous Linum tenue. Building on a high-quality genome assembly, we show that L. trigynum harbors a genomic region homologous to the dominant haplotype of the distyly supergene conferring long stamens and short styles in L. tenue, suggesting that loss of distyly first occurred in a short-styled individual. In contrast to homostylous Primula and Fagopyrum, L. trigynum harbors no fixed loss-of-function mutations in coding sequences of S-linked distyly candidate genes. Instead, floral gene expression analyses and controlled crosses suggest that mutations downregulating the S-linked LtWDR-44 candidate gene for male self-incompatibility and/or anther height could underlie homostyly and self-compatibility in L. trigynum. Population genomic analyses of 224 whole-genome sequences further demonstrate that L. trigynum is highly self-fertilizing, exhibits significantly lower genetic diversity genome-wide, and is experiencing relaxed purifying selection and less frequent positive selection on nonsynonymous mutations relative to L. tenue. Our analyses shed light on the loss of distyly in L. trigynum, and advance our understanding of a common evolutionary transition in flowering plants.

Ventilatory associated barotrauma in COVID-19 patients: A multicenter observational case control study (COVI-MIX-study).

BACKGROUND: The risk of barotrauma associated with different types of ventilatory support is unclear in COVID-19 patients. The primary aim of this study was to evaluate the effect of the different respiratory support strategies on barotrauma occurrence; we also sought to determine the frequency of barotrauma and the clinical characteristics of the patients who experienced this complication. METHODS: This multicentre retrospective case-control study from 1 March 2020 to 28 February 2021 included COVID-19 patients who experienced barotrauma during hospital stay. They were matched with controls in a 1:1 ratio for the same admission period in the same ward of treatment. Univariable and multivariable logistic regression (OR) were performed to explore which factors were associated with barotrauma and in-hospital death. RESULTS: We included 200 cases and 200 controls. Invasive mechanical ventilation was used in 39.3% of patients in the barotrauma group, and in 20.1% of controls (p<0.001). Receiving non-invasive ventilation (C-PAP/PSV) instead of conventional oxygen therapy (COT) increased the risk of barotrauma (OR 5.04, 95% CI 2.30 - 11.08, p<0.001), similarly for invasive mechanical ventilation (OR 6.24, 95% CI 2.86-13.60, p<0.001). High Flow Nasal Oxygen (HFNO), compared with COT, did not significantly increase the risk of barotrauma. Barotrauma frequency occurred in 1.00% [95% CI 0.88-1.16] of patients; these were older (p=0.022) and more frequently immunosuppressed (p=0.013). Barotrauma was shown to be an independent risk for death (OR 5.32, 95% CI 2.82-10.03, p<0.001). CONCLUSIONS: C-PAP/PSV compared with COT or HFNO increased the risk of barotrauma; otherwise HFNO did not. Barotrauma was recorded in 1.00% of patients, affecting mainly patients with more severe COVID-19 disease. Barotrauma was independently associated with mortality. TRIAL REGISTRATION: this case-control study was prospectively registered in clinicaltrial.gov as NCT04897152 (on 21 May 2021).

Assessment of COVID-19 progression on day 5 from symptoms onset.

BACKGROUND: A major limitation of current predictive prognostic models in patients with COVID-19 is the heterogeneity of population in terms of disease stage and duration. This study aims at identifying a panel of clinical and laboratory parameters that at day-5 of symptoms onset could predict disease progression in hospitalized patients with COVID-19. METHODS: Prospective cohort study on hospitalized adult patients with COVID-19. Patient-level epidemiological, clinical, and laboratory data were collected at fixed time-points: day 5, 10, and 15 from symptoms onset. COVID-19 progression was defined as in-hospital death and/or transfer to ICU and/or respiratory failure (PaO2/FiO2 ratio < 200) within day-11 of symptoms onset. Multivariate regression was performed to identify predictors of COVID-19 progression. A model assessed at day-5 of symptoms onset including male sex, age > 65 years, dyspnoea, cardiovascular disease, and at least three abnormal laboratory parameters among CRP (> 80 U/L), ALT (> 40 U/L), NLR (> 4.5), LDH (> 250 U/L), and CK (> 80 U/L) was proposed. Discrimination power was assessed by computing area under the receiver operating characteristic (AUC) values. RESULTS: A total of 235 patients with COVID-19 were prospectively included in a 3-month period. The majority of patients were male (148, 63%) and the mean age was 71 (SD 15.9). One hundred and ninety patients (81%) suffered from at least one underlying illness, most frequently cardiovascular disease (47%), neurological/psychiatric disorders (35%), and diabetes (21%). Among them 88 (37%) experienced COVID-19 progression. The proposed model showed an AUC of 0.73 (95% CI 0.66-0.81) for predicting disease progression by day-11. CONCLUSION: An easy-to-use panel of laboratory/clinical parameters computed at day-5 of symptoms onset predicts, with fair discrimination ability, COVID-19 progression. Assessment of these features at day-5 of symptoms onset could facilitate clinicians' decision making. The model can also play a role as a tool to increase homogeneity of population in clinical trials on COVID-19 treatment in hospitalized patients.

Long-Term Patient-Centred Follow-up in a Prospective Cohort of Patients with COVID-19.

INTRODUCTION: To better define COVID-19 long-term impact we prospectively analysed patient-centred outcomes, including general health and symptom duration. METHODS: Barthel index (BI), St. George's Respiratory Questionnaire adapted to patients with COVID-19 (aSGRQ) and WHO Clinical Progression Scale (CPS) were measured at enrolment and at 6 weeks from the onset of symptoms. Persistence of most frequently reported symptoms was assessed at 6 weeks and, among symptomatic patients, at 12 weeks from the onset of symptoms. Predictors of impaired general health over time were identified using an ordinal multilevel multivariate model. RESULTS: A total of 448 patients (55% men, median age 56 years) were enrolled. WHO-CPS showed mild, moderate and severe disease in 48%, 42% and 10% of patients at admission and mild disease in all patients at follow-up, respectively. BI and aSGRQ were normal in 96% and 93% patients before COVID-19 but only in 47% and 16% at COVID-19 diagnosis and in 87% and 65% at 6-week follow-up. Male gender was identified by all three assessments as a predictor of impaired general health (BI, OR 2.14, p < 0.0001; aSGRQ, OR 0.53, p = 0.003; WHO-CPS, OR 1.56, p = 0.01). Other predictors included age, ICU admission and comorbidities (e.g. cardiovascular disease and cancer) for BI, hospital admission for aSGRQ, age and presence of comorbidities for WHO-CPS. At 6- and 12-week follow-up, 39% and 20% of patients, respectively, were still reporting symptoms. Fatigue and breathlessness were the most frequently reported symptoms. CONCLUSIONS: Long-term follow-up facilitates the monitoring of health impairment and symptom persistence and can contribute to plan tailored interventions.

Degenerative spine disease: Italian position paper on acquisition, interpretation and reporting of Magnetic Resonance Imaging.

OBJECTIVE: To promote a better radiological interpretation of spine degeneration, a consistent standardization of the acquisition, interpretation and description of Magnetic Resonance Imaging (MRI) l findings. MATERIALS AND METHODS: In order to achieve this objective, a consensus among experts in imaging of degenerative spine disease (DSD) from Italian radiological societies (SIRM-Italian Society of Radiology, AINR-Italian Association of Neuroradiology) was achieved. The representatives of the Italian inter-societal working group examined the literature produced by European/American task forces on optimizing the study sequences, classification of degenerative disc changes, spondylo-arthrosis, osteochondrosis, synovial and ligament pathologies of the spinal column, and on canal and foraminal stenosis. The document-resulted from the consensus between experts-was then presented to the scientific societies of Neurosurgery (SINCH) and Orthopedics and Traumatology (SIOT) for their approval. RESULTS: This position paper presents a proposal for an optimized MRI protocol for studying DSD and provides a glossary of terms related to this pathology and indications on their use. The international terminological recommendations have been translated and adapted to the Italian language and clinical practice and clinical cases have been used to illustrate some of the main classifications. CONCLUSIONS: This revision of international DSD guidelines/recommendations and consensus made it possible to (1) update the nomenclature to international standards and (2) harmonize the MRI protocol and description of radiological findings, adapting both (1, 2) to the Italian context. With this position paper we intend to contribute to an improvement of the communication among doctors and between physicians and their patients as well as the quality of the radiological reports.

Increase in visceral adipose tissue in a woman living with HIV after introduction of integrase strand transfer inhibitor.

Integrase strand transfer inhibitors (INSTIs) are a class of antiretroviral drugs with high virologic efficacy and excellent tolerability. Recent evidence showed a possible link of dolutegravir-based regimens with weight gain, and a relationship between raltegravir use and changes in adipose tissue density and metabolic abnormalities, with an increased cardiovascular risk, has been suggested. We describe a case where dolutegravir monotherapy led to a decrease in adipose tissue density.

Pitfalls of Computed Tomography in the Coronavirus 2019 (COVID-19) Era: A New Perspective on Ground-Glass Opacities.

Aim To study ground-glass opacities (GGO) not only from the coronavirus 2019 (COVID-19) pneumonia" perspective but also as a radiological presentation of other pathologies with comparable features. Methods We enrolled 33 patients admitted to Policlinico Universitario G. B. Rossi who underwent non-contrast-enhanced (NCE) or contrast-enhanced (CE) chest computed tomography (CT) between March 12 and April 12. All patients with CT-detected ground-glass opacity (GGO) were included. All patients resulted as COVID-19 negative at the reverse transcription-polymerase chain reaction (RT-PCR) assay. We studied the different pathologies underlying GGO features: neoplastic diseases and non-neoplastic diseases (viral pneumonias, interstitial pneumonias, and cardiopulmonary diseases) in order to avoid pitfalls and to reach the correct diagnosis. Results All CT scans detected GGOs. Symptomatic patients were 25/33 (75.7%). At the clinical presentation, they reported fever and dry cough; in six out of 25 cases, dyspnea was also reported (24%). Thirty-three (33; 100%) showed GGO at CT: 15/33 (45.45%) presented pure GGO, and 18/33 (54.54%) showed GGO with consolidation. The RT-PCR assay was negative in 100%. We investigated other potential underlying diseases to explain imaging features: neoplastic causes (8/33, 24.24%) and non-neoplastic causes, in particular, infectious pneumonias (16/33, 48,48 %, viral and fungal), interstitial pneumonias (4/33, 12,12%), and cardio-pulmonary disease (5/33, 15,15%). Conclusions GGO remains a diagnostic challenge. Although CT represents a fundamental diagnostic tool because of its sensitivity, it still needs to be integrated with clinical data to achieve the best clinical management. In the presence of typical imaging features (e.g. GGO and consolidation), the radiologist should focus on the pandemic and manage a suspect patient as COVID-19 positive until proven to be negative.

The Protease Inhibitor CI2c Gene Induced by Bird Cherry-Oat Aphid in Barley Inhibits Green Peach Aphid Fecundity in Transgenic Arabidopsis.

Aphids are phloem feeders that cause large damage globally as pest insects. They induce a variety of responses in the host plant, but not much is known about which responses are promoting or inhibiting aphid performance. Here, we investigated whether one of the responses induced in barley by the cereal aphid, bird cherry-oat aphid (Rhopalosiphum padi L.) affects aphid performance in the model plant Arabidopsis thaliana L. A barley cDNA encoding the protease inhibitor CI2c was expressed in A. thaliana and aphid performance was studied using the generalist green peach aphid (Myzus persicae Sulzer). There were no consistent effects on aphid settling or preference or on parameters of life span and long-term fecundity. However, short-term tests with apterous adult aphids showed lower fecundity on three of the transgenic lines, as compared to on control plants. This effect was transient, observed on days 5 to 7, but not later. The results suggest that the protease inhibitor is taken up from the tissue during probing and weakly inhibits fecundity by an unknown mechanism. The study shows that a protease inhibitor induced in barley by an essentially monocot specialist aphid can inhibit a generalist aphid in transgenic Arabidopsis.

Pancreatic duct stenosis: Differential diagnosis between malignant and benign conditions at secretin-enhanced MRCP.

PURPOSE: To define imaging criteria of benign and malignant nature in patients with main pancreatic duct (MPD) stenosis. MATERIALS-METHODS: S-MRCPs of 35 patients with pancreatitis and 14 with adenocarcinoma were evaluated. RESULTS: Adenocarcinoma caused higher prevalence of complete stenosis (14/14-100% vs 17/35-49%), dilated side-branches (14/14-100% vs 18/35-51%) and lower prevalence of duct-penetrating sign (0/14-0% vs 31/35-89%). The number of stenoses was higher in benign conditions (mean 1.4 Vs 1). Upstream MPD diameter was higher in cancer-induced stenoses (4.5 vs 2.9mm). CONCLUSIONS: Single complete stenosis with dilated side branches, increased MPD caliber and absent duct-penetrating sign are suggestive of malignancy.

Pancreatic mucinous cystoadenomas and cystoadenocarcinomas: differential diagnosis by means of MRI.

OBJECTIVE: To determine the accuracy of MRI in differentiating mucinous cystoadenomas (MCAs) from mucinous cystoadenocarcinomas (MCACs) of the pancreas, with histopathological analysis as the reference standard, for better surgical planning. METHODS: A total of 65 patients with histopathologically proven mucinous cystic neoplasms (MCNs) underwent MRI and surgery. Quantitative image analysis included size, septa and wall thickness and number of loculations. Qualitative image analysis included nodules; hyperintensity of the cystic content on T1 weighted images; compression and/or infiltration of adjacent vessels or organs; and metastases. A comparison between MCAs and MCACs was performed with Student's t-test for quantitative variables and with Fisher test for qualitative variables. Receiver operating characteristic analysis was performed to determine the accuracy in the differential diagnosis between MCAs and MCACs on the basis of a score system obtained by giving 1 point for each quantitative and qualitative variable observed in each patient. RESULTS: At histopathology, 43 lesions were MCAs and 22 lesions were MCACs. A statistically significant difference was observed for size >7cm (<0.001), septa and wall thickness >3 mm (<0.0001), number of loculations >4 (<0.0001), nodules (<0.0001), hyperintensity of the cystic content on T1 weighted images (<0.0001), compression (<0.01) and/or infiltration (<0.01) of adjacent vessels or organs and metastases (<0.05). The best cut-off value to discriminate MCAs from MCACs was the presence of three features (p < 0.001), with an accuracy of 91%. CONCLUSION: MRI has an accuracy of 91% in the differential diagnosis between MCA and MCAC, helping in identifying forms that could undergo parenchyma-sparing surgery (MCAs), reducing post-surgical morbidity and mortality. ADVANCES IN KNOWLEDGE: In this study, the differentiation between MCAs and MCACs of the pancreas by means of MRI is addressed. The differential diagnosis allows selecting benign forms, susceptible of parenchyma-sparing surgery, with the advantage of reducing post-surgical morbidity and stratifying prognosis of MCNs.

Santorinicele: secretin-enhanced magnetic resonance cholangiopancreatography findings before and after minor papilla sphincterotomy.

OBJECTIVES: To evaluate secretin-enhanced MRCP (S-MRCP) findings of patients with pancreas divisum and Santorinicele, before and after minor papilla sphincterotomy. METHODS: S-MRCP examinations of 519 patients with suspected pancreatic disease were included. Size of the main pancreatic duct, presence and calibre of Santorinicele were evaluated. Duodenal filling was assessed on dynamic images. After sphincterotomy the same parameters and the clinical findings were re-evaluated. RESULTS: Pancreas divisum was depicted in 55/519 patients (11 %) by MRCP and an additional 26/519 by S-MRCP (total 81/519, 16 %). Santorinicele was detected in 7/81 patients (8.6 %) with pancreas divisum by MRCP and an additional 20/81 by S-MRCP (total 27/81, 33 %). Dorsal duct in patients with Santorinicele was significantly larger in the head compared with patients with only pancreas divisum (p < 0.01), in basal conditions (average 2.4 versus 1.9 mm) and after secretin administration (average 3.0 versus 2.4 mm). Duodenal filling was impaired in 11/27 patients (41 %) with Santorinicele. After sphincterotomy significant reduction in size of Santorinicele (-33 %) and dorsal duct (-17 %), increase of pancreatic juice and symptoms improvement were observed. CONCLUSION: Secretin administration increases the accuracy of MRCP in detecting Santorinicele and demonstrates the impaired duodenal filling. S-MRCP is useful to assess results of sphincterotomy. KEY POINTS: • Secretin-enhanced MRCP gives anatomical and functional information on pancreatic outflow dynamics. • Santorinicele is a cystic dilatation of the termination of the Santorini duct. • S-MRCP images are the most useful to recognize the presence of Santorinicele. • Minor papilla sphincterotomy during ERCP is indicated in patients with Santorinicele.

Mucinous cystic neoplasms and serous cystadenomas arising in the body-tail of the pancreas: MR imaging characterization.

PURPOSE: To identify magnetic resonance (MR)/MR cholangiopancreatography (MRCP) imaging signs helpful in the differential diagnosis between serous cystadenomas (SCAs) and mucinous cystic neoplasms (MCNs), arising from the body/tail of the pancreas. MATERIAL AND METHODS: This retrospective study had institutional review board approval and informed consent was waived. Fifty-three patients with non-communicating cystic pancreatic neoplasm of the body/tail, undergoing MR/MRCP, were included. Qualitative image analysis assessed the macroscopic pattern, number of cysts, presence of central scar, contrast enhancement of peripheral wall, and mural nodules. Quantitative analysis assessed the maximum diameter of the neoplasm, thickness of the peripheral wall, and calibre of the upstream main pancreatic duct. RESULTS: Histopathology results revealed that 27/53 (51 %) were SCAs, 26/53 (49 %) were MCNs. Microcystic pattern was observed in 88.2 % of SCAs and 11.8 % of MCNs; macrocystic pattern was observed in 90.5 % of MCNs and 9.5 % of SCAs (p < 0.0001). Central scar was detected in 29.6 % of SCAs and no MCNs (p = 0.003). Contrast enhancement of the peripheral wall was evident in 99.5 % of MCNs and 11.5 % of SCAs (p < 0.0001); mural nodules were depicted in 94.1 % of MCNs and 5.9 % of SCAs (p < 0.0001). Median maximum diameter was 54 mm for MCNs, 32 mm for SCAs (p = 0.001); median wall thickness was 4 mm for MCNs, 2 mm for SCAs (p < 0.0001). CONCLUSIONS: Macrocystic pattern, enhancement of a peripheral wall and mural nodules are suggestive of MCNs; whereas microcystic pattern, lack of peripheral wall and central scar are suggestive of SCAs. KEY POINTS: • MCNs have macrocystic patterns, contrast enhancement of the peripheral wall and mural nodules • Microcystic pattern and central scar are suggestive of SCA • Mural nodules detected in MCNs correlate with epithelial dysplasia • Chronic obstructive pancreatitis is equally depicted in patients with MCNs and SCAs.

Pancreatic duct abnormalities in focal autoimmune pancreatitis: MR/MRCP imaging findings.

AIM: To evaluate the magnetic resonance (MR) imaging-MR cholangiopancreatographic (MRCP) findings of focal forms of autoimmune pancreatitis (AIP) to describe ductal involvement at diagnosis. METHODS: MR examinations of 123 patients affected by AIP were analysed. We included 26 patients who satisfied International Consensus Diagnostic Criteria and were suffering from focal AIP. Image analysis included: site of parenchymal enlargement, main pancreatic duct (MPD) diameter, MPD stenosis, stricture length, presence of upstream dilation within the stricture, signal intensity, and pancreatic enhancement. RESULTS: Signal intensity abnormalities were localized in the head in 10/26 (38.5%) and in the body-tail in 16/26 (61.5%) patients. MRCP showed a single MPD stenosis in 12/26 (46.1%) and multiple MPD stenosis in 14/26 (53.8%) patients, without a dilation of the upstream MPD (mean: 3.83 mm). Lesions showed hypointensity on T1-weighted images in all patients, and hyperintensity on T2-weighted images in 22/26 (84.6%) patients. The affected parenchyma was hypovascular during the arterial phase in 25/26 (96.2%) patients with contrast retention. CONCLUSIONS: MR-MRCP are effective techniques for the diagnosis of AIP showing the loss of the physiological lobulation and the typical contrastographic appearance. The presence of multiple, long stenoses without an upstream MPD dilation at MRCP suggests the diagnosis of AIP, and can be useful in differential diagnosis of pancreatic adenocarcinoma. KEY POINTS: • MRI represents the gold standard in the diagnosis of AIP. • MRCP is an increasingly useful technique in the diagnosis of focal AIP. • MRCP could be a problem-solving tool in the differential diagnosis of AIP.

MRI features of solid pseudopapillary neoplasm of the pancreas.

PURPOSE: To evaluate the magnetic resonance imaging (MRI) findings of solid pseudopapillary neoplasm (SPN) of the pancreas. METHODS AND MATERIALS: From January 2006 to December 2013, 41 patients with SPN of the pancreas were retrospectively evaluated. Inclusion criteria were the execution of an MR examination and tumor resection with an histopathological evaluation at our Institute. Exclusion criteria were the execution of an MR examination at other centers (14/41) and the execution of CT or ultrasonography (10/41) at our Institute. The qualitative analysis evaluated: location (head/body-tail), shape (round/oval/lobulated), margins (regular/irregular), and signal intensity on T1- and T2-weighted images compared to the surrounding pancreas (hypo-, iso-, or hyperintense and homogeneous or heterogeneous), appearance of MPD and the secondary ducts, and the presence of metastases and/or vascular involvement. The quantitative analysis included: maximum size of the lesion, wall thickness, and maximum diameter of the main pancreatic duct (MPD). RESULTS: The population comprised 17 women (median age: 31 year) with a median tumor size of 50.6 mm, a median wall thickness of 2 mm and median diameter of the MPD of 1.8 mm. 9/17 were at the head; 8/17 on the body/tail: respectively, 8/17 round, 6/17 oval, and 3/17 lobulated. All showed regular margins. On T1-weighted images 8/17 appeared homogeneously hypointense, 7/17 heterogeneously hypointense, and 2/17 heterogeneously hyperintense. On T2-weighted images 1/17 appeared homogeneously hyperintense and 16/17 heterogeneously hyperintense. No secondary ducts dilatations were detected. During the follow-up, one patient presented disease recurrence 48 months after surgery. CONCLUSIONS: MR imaging features can be highly suggestive for the diagnosis of SPN.

Evolution of ventriculomegaly: comparison between foetal MR imaging and postnatal diagnostic imaging.

PURPOSE: We evaluated the evolution of ventriculomegaly (VM) by comparing foetal magnetic resonance imaging (MRI) with postnatal transcranial ultrasonography (US) and/or encephalic MRI. MATERIALS AND METHODS: Between January 2006 and April 2011, 70 foetuses with a mean gestational age of 28 weeks and 4 days (range, 18-36) weeks with VM on foetal MRI were assessed in this prospective study. Half-Fourier rapid acquisition with relaxation enhancement (RARE) T2-weighted, T1-weighted and diffusion-weighted (DWI) images along the three orthogonal planes according to the longitudinal axis of the mother, and subsequently of the foetal brain, were acquired. Quantitative image analysis included the transverse diameter of lateral ventricles in axial and coronal planes. Qualitative image analysis included searching for associated structural anomalies. RESULTS: Thirty-four of 70 patients with a diagnosis of VM on foetal MRI underwent postnatal imaging. Twenty-five of those 34 (73%) had mild, four (12%) had moderate and five (15%) had severe VM on MRI. Normalisation of the diameter of lateral ventricles was observed in 16 of the 34 (47%) newborns. Among these 16, 13 (81%) had mild and three (19%) had moderate VM (two isolated and one associated VM). VM stabilisation was observed in 16 of the 34 (47%) babies. Among them, 11 (69%) had mild (eight isolated and three associated), one (6%) had moderate associated and four (25%) had severe associated VM. Progression from mild to severe (associated) VM was observed in two of the 34 (6%) babies. CONCLUSIONS: The absence of associated anomalies and a mild VM are favourable prognostic factors in the evolution of VM.

The Casuarina glauca metallothionein I promoter in nodulated transgenic hairy roots of the actinorhizal plant Datisca glomerata.

The activity of the promoter of a metallothionein gene expressed in actinorhizal nodules of Casuarina glauca Sieber ex Spreng., CgMT1, has previously been analysed in Casaurinaceae and in tobacco (Nicotiana tabacum L.), Arabidopsis and rice. In all these plants, the promoter showed high activity in the root cortex and epidermis, making it a useful tool for the expression of transgenes. Therefore, its activity was now analysed in transgenic root systems of Datisca glomerata (C. Presl) Baill, an actinorhizal plant from a different phylogenetic group than C. glauca, using the same CgMT1::GUS fusion as in previous studies. However, in contrast with all other plant species examined previously, the CgMT1::GUS construct showed no activity at all in D. glomerata hairy roots: the expression pattern in nodules resembled that found in C. glauca nodules. This is probably due to the changed hormone balance in hairy roots since experiments on the CgMT1::GUS construct in transgenic Arabidopsis showed that CgMT1 promoter activity was repressed by auxin or cytokinin, respectively. Yet, in hairy roots of the model legume Lotus japonicus L. induced by the same Agrobacterium rhizogenes strain, the CgMT1 promoter was active in roots and not in nodules. These results indicate that although the expression of pRi T-DNA genes leads to changes in root hormone balance, these changes do not abolish the differences in phytohormone levels or sensitivity between plant species. Therefore, gene expression data obtained using transgenic hairy root systems have to be viewed with care, not only due to the disturbed hormone balance, but also because the effects of the pRI-T-DNA genes can differ between species.

Effect of fluoride varnish on enamel demineralization around brackets: an in-vivo study.

INTRODUCTION: Even with advances in materials and techniques, demineralization around brackets during orthodontic treatment continues to be a problem. The purpose of this in-vivo study was to evaluate the effect of a fluoride varnish on enamel demineralization adjacent to bonded brackets. METHODS: Fifteen patients who needed at least 2 premolars extracted for orthodontic reasons were selected. In each patient, 1 premolar was considered the test tooth, and the other was the control. Brackets were bonded, and T-loops were engaged on all premolars, but only the test teeth received fluoride varnish. The premolars were extracted after 85 to 95 days, and buccolingual sections 50 to 70 microm in thickness were evaluated with polarized light microscopy. The mean depth of demineralization in each lesion was measured 3 times on photographs by an operator blinded to the groups (intraclass correlation of the 3 measurements was 0.988). RESULTS: The mean lesion depths were 57.0 +/- 5.5 microm in the test group and 94.3 +/- 6.7 microm in the control group. There was significant reduction (approximately 40%) in depth of demineralization in the test group (P <.001). CONCLUSIONS: Fluoride varnish can be beneficial as a preventive adjunct in reducing demineralization adjacent to brackets.