Experimental design and field deployment of an artificial bio-reef produced by mollusk shell recycling

Shellfish farming is considered a highly sustainable form of aquaculture that has developed rapidly worldwide. Unfortunately, today biological and chemical pollution of the oceans and marine waters is widespread and has multiple negative impacts on marine ecosystems, which are exacerbated by global climate changes. In addition, such impacts on fisheries and aquaculture are significant in inducing socio-economic losses. Therefore, it is necessary to develop innovative solutions to improve productivity and environmental performance in line with the blue sustainable economy (European Green Deal). However, one upcoming problem associated with shellfish consumption is shell waste and its disposal. In addition, the percentage of wasted shells destined for reuse is much lower than the one accumulated in landfills or in more or less well-managed sites. This represents a weakness of the shellfish farming sector that can only be mitigated through a project of shellfish waste recycling moving towards the circular economy, with undoubted environmental and economic advantages. In the present study, we present a possible solution for recycling clam shells coming from the waste of the fishing industry (circular economy). Indeed, three eco-friendly bio-reefs for the stabilization and implementation of marine biodiversity (blue economy) were realized using additive manufacturing technology (3D printing) for large dimensions (technological innovation). Furthermore, before deploying the reefs on the sea bottom, they were colonized with oysters to promote repopulation.

An intelligent clustering method for devising the geochemical fingerprint of underground aquifers

Geochemical fingerprinting is a rapidly expanding discipline in the earth and environmental sciences, anchored in the recognition that geological processes leave behind physical, chemical and sometimes also isotopic patterns in the samples. Furthermore, the geochemical fingerprinting of natural cycles (water, carbon, soil and biota fingerprinting) are influenced by the anthropogenic impact and by the climate change. So, their monitoring is a tool of resilience and adaptation. In recent years, computational statistics and artificial intelligence methods have started to be used to help the process of geochemical fingerprinting. In this paper we consider data from 57 wells located in the province of Ferrara (Italy), all belonging to the same geological group and separated into 4 different aquifers. The aquifer from which each well extracts its water is known only in 18 of the 57 cases, while in other 39 cases it can be only hypothesized based on geological considerations. We devise a novel technique for geochemical fingerprinting of groundwater by means of which we are able to identify the exact aquifer from which a sample is extracted with a sufficiently high accuracy. Then, we experimentally prove that out method is sensibly more accurate than typical statistical approaches, such as principal component analysis, for this particular problem.

Knowledge, attitude and practice on antibiotic use and resistance among the Italian population, 2019

Background

Public knowledge, awareness and behaviors related to antibiotic use and antimicrobial-resistance (AMR) are vital to ensure the prudent use of these drugs. In this work, we present the top-line results of the first national survey of AMR among the Italian general population aged ≥18 years.

Methods

From August to September 2019, we conducted a population-based cross-sectional random survey through mixed CATI/CAMI/CAWI methodologies among representative samples of the general population, parents of children aged 0-11 years, adults ≥65 years and pet's owners. Results were summarized using relative frequencies.

Results

Of 1,400 persons interviewed, 47% and 68% respectively correctly said that it is false that antibiotics kill viruses and are effective at treating colds and flu. More than 80% of respondents considered themselves to be well-informed about antibiotics but only one in two people knew what is meant by AMR. While the vast majority (96%) of respondents said that they obtained the last course of antibiotics that they used from a medical prescription, 11% incorrectly said that they stopped taking antibiotics when they felt better or that they used those left over from a previous course. In addition, 55% of pet's owners said they obtained antibiotics without a prescription from a pharmacy or elsewhere. Almost all respondents (97%) believed that it's everyone's responsibility to use antibiotics wisely, with the 80% who expressed concerns about the potential of AMR to affect themselves and their families; however, 40% did not think that action at an individual level is the most effective way of tackling resistance to antibiotics.

Conclusions

Our findings show some improvement in Italians' knowledge, awareness and behaviors related to antibiotic use and AMR but there are needs to be a greater sense of responsibility to take charge of the AMR problem. These results may be drivers of structured national awareness campaigns.

Key messages

In 2019, we conducted the first national survey of AMR among the Italian population: >80% of respondents felt themselves well-informed about antibiotics but only 1/2 people knew what is meant by AMR. Almost all Italian sample believed that it's everyone's responsibility to use antibiotics wisely, but 40% did not think that action at an individual level is effective to tackle AMR.

Diabetes vulnerability in Rome

Background

To understand the presence and impact of social and cultural factors on health vulnerability it is important for improving diabetes care and management. In fact, through the social dimension, it is possible to identify the priorities and attitudes towards diabetes and diabetes care among those living with the condition.

Methods

The study was carried out as part of the global Cities Changing Diabetes programme, involved a sample of individuals living with diabetes in the Rome metropolitan area and employed mixed-method and qualitative approaches to data collection and analysis (survey, sorting procedure and focus group).

Results

Four specific sub-groups of participants have been identified, each with distinct but shared priorities and attitudes towards diabetes: Health conscious thanks to the context; Medicalized elderly people; Fatalistic citizens; Worried but undisciplined young people. The connection between the place where you live and the possibility to adopt a healthier lifestyle was confirmed. For these patients, the disease is mainly characterized by its relationship with food and its connections with psychological aspects are also relevant.

Conclusions

An important issue concerns information and the different understandings of diabetes. A clear need emerged for further elaboration of the various aspects of a disease that tends to be underestimated also by those who have it. Another aspect concerns the importance of the living environment and consequently of the actions on its urban planning, mobility, but also in everyday life organization, as factors that can make a difference in properly managing the disease. These results are very important to promote a joint action, that have to involve public and private stakeholders, in order to improve treatment opportunities and quality of life of people facing diabetes every day in the Rome metropolitan area.

Key messages

An important issue concerns information. A clear need emerged for further elaboration of the various aspects of a disease that tends to be underestimated also by those who have it. The living environment in important too and the actions on its urban planning, mobility, in everyday life organization, as factors that can make a difference in properly managing the disease.

Benquerencia (La Serena - Spain) rock art: An integrated spectroscopy analysis with FTIR and Raman

La Serena region is a large plateau with open landscapes bounded in the south by a mountain chain formed by the Benquerencia, Tiros and La Rinconada Sierras. There are more than 300 painted and engraved sites in the region. Cueva Grande, Cueva de En medio and Cueva Pequeña are three Schematic rock art shelters located in the municipality of Benquerencia de la Serena, Badajoz, Spain. Over their panels have been documented more than a hundred of painted schematic figures (anthropomorphic figures, eye-shape figures and symbols) (Neolithic - Copper Age). Paintings are monochromatic with red or black coloration. A total of 13 samples (10 red and 3 black samples) from different panels were collected and analyzed using micro-Raman spectroscopy and ATR-FTIR. Micro-Raman spectroscopy was able to characterize the main mineral component, respectively hematite for the red figures and charcoal for the black paintings. ATR-FTIR was useful to possible ochre and possible organic identification. These latest results are particularly important for understanding manufacturing processes and addressing conservation problems.

High-resolution Light Microscopy (HRLM) and Digital Analysis of Pompe Disease Pathology

Pompe disease is an autosomal recessive lysosomal storage disorder caused by a deficiency of the lysosomal enzyme acid α-glucosidase, responsible for the degradation of lysosomal glycogen. Absent or low levels of the enzyme leads to lysosomal glycogen accumulation in cardiac and skeletal muscle cells, resulting in progressive muscle weakness and death from cardiac or respiratory failure. Recombinant enzyme replacement and gene therapy are now being investigated as treatment modalities for this disease. A knockout mouse model for Pompe disease, induced by the disruption of exon 6 within the acid α-glucosidase gene, mimics the human disease and has been used to evaluate the efficacy of treatment modalities for clearing glycogen. However, for accurate histopathological assessment of glycogen clearance, maximal preservation of in situ lysosomal glycogen is essential. To improve retention of glycogen in Pompe tissues, several fixation and embedding regimens were evaluated. The best glycogen preservation was obtained when tissues fixed with 3% glutaraldehyde and postfixed with 1% osmium tetroxide were processed into epon-araldite. Preservation was confirmed by staining with the Periodic acid-Schiff's reaction and by electron microscopy. This methodology resulted in high-resolution light microscopy (HRLM) sections suitable for digital quantification of glycogen content in heart and skeletal muscle. Combining this method of tissue fixation with computer-assisted histomorphometry has provided us with what we believe is the most objective and reproducible means of evaluating histological glycogen load in Pompe disease.

Stroke units in Italy: engaging the public in optimizing existing resources

BACKGROUND AND PURPOSE

The lack of a wide implementation of stroke units (SU)s in Italy appears to accompany the underuse of the operating units. Community awareness of acute stroke care options may affect stroke resource use. Our aim was to determine the level of knowledge about SUs and tissue-plasminogen activator (t-PA) treatment amongst Italian adults and investigate its relationship to local stroke services implementation.

METHODS

A nation-based telephone survey was carried out in a sample of 1000 residents aged >18 years in May-June 2010. The questionnaire included close-ended questions regarding knowledge of SUs and t-PA treatment. Number and location of both SUs and t-PA treatments were provided by a concurrent national hospital-based survey. The prevalence and distribution of acute stroke care awareness in the community was examined and multivariate analyses were generated.

RESULTS

Amongst the 1000 participants (474 men, mean age 48.8 ± 17.2), only 26.2% reported knowing about the availability of t-PA treatment and only 15% were aware of the existence of SUs. Awareness of both SUs and t-PA was significantly associated only with education. These associations remained significant in the multivariate analyses. The degree of stroke services implementation (in terms of SUs/inhabitant rates and number of t-PA treatments) was not associated with SU and t-PA awareness.

CONCLUSIONS

This is the first European study that explored public knowledge about t-PA treatment and SUs. Italian adults proved insufficiently educated about SUs and t-PA; there is no higher awareness in areas with a greater supply of stroke services. This might partially explain the underuse of Italian SUs.

Validation of Automatic Contour Propagation for 4D Treatment Planning Using Multiple Metrics

The aim of this work is to provide insights into multiple metrics clinical validation of deformable image registration and contour propagation methods in 4D lung radiotherapy planning. The following indices were analyzed and compared: Volume Difference (VD), Dice Similarity Coefficient (DSC), Positive Predictive Value (PPV) and Surface Distances (SD). The analysis was performed on three patient datasets, using as reference a ground-truth volume generated by means of Simultaneous Truth And Performance Level Estimation (STAPLE) algorithm from the outlines of five experts. Significant discrepancies in the quality assessment provided by the different metrics in all the examined cases were found. Metrics sensitivity was more evident in presence of image artifacts and particularly for tubular anatomical structures, such as esophagus or spinal cord. Volume Differences did not account for position and DSC exhibited criticalities due to its intrinsic symmetry ( i.e. over- and under-estimation of the reference contours cannot be discriminated) and dependency on the total volume of the structure. PPV analysis showed more robust performance, as each voxel concurs to the classification of the propagation, but was not able to detect inclusion of propagated and ground-truth volumes. Mesh distances could interpret the actual shape of the structures, but might report higher mismatches in case of large local differences in the contour surfaces. According to our study, the combination of VD and SD for the validation of contour propagation algorithms in 4D could provide the necessary failure detection accuracy.

The MSH2 c.388_389del mutation shows a founder effect in Portuguese Lynch syndrome families

The MSH2 c.388_389del mutation has occasionally been described in Lynch families worldwide. At the Portuguese Oncology Institute in Porto, Portugal, we have identified 16 seemingly unrelated families with this germline mutation. To evaluate if this alteration is a founder or a recurrent mutation we performed haplotype analysis in the 16 Portuguese index cases and 55 relatives, as well as in four index cases and 13 relatives reported from Germany, Scotland, England, and Argentina. In the Portuguese families we observed a shared haplotype of approximately 10 Mb and all were originated from the north of Portugal. These results suggest that this alteration is a founder mutation in Portugal with a relatively recent origin. In the reported families outside Portugal with this mutation different haplotype backgrounds were observed, supporting the hypothesis that it occurred de novo on multiple occasions. We also conclude that the high proportion of families with the MSH2 c.388_389del mutation indicates that screening for this alteration as a first step may be cost-effective in the genetic testing of Lynch syndrome suspects of Portuguese ancestry, especially those originating from the north of Portugal.

Hereditary diffuse gastric cancer: Natural history, pathology, screening limitations, and prophylactic total gastrectomy in CDH1 mutation carriers

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Background: Hereditary diffuse gastric cancer (HDGC) is a potentially fatal disease that occurs due to mutations in the E- cadherin (CDH1) gene, as discovered in 1998. Its penetrance ranges between 70–80%. Its morbidity and mortality can be altered favorably through genetic counseling, germline mutation testing, and highly-targeted management that includes prophylactic total gastrectomy. Lobular breast cancer has been identified as an integral lesion in HDGC. Methods: This international collaborative group on HDGC is comprised of 56 mutation-positive families, which is the world’s largest resource of such families. Cancer diagnoses were verified with pathology slides/tissue block review when possible, or reports. Genetic counseling covering the pros and cons of mutation testing, screening and its limitations, and the option of prophylactic total gastrectomy was provided. Results: Findings on 56 HDGC mutation-positive families show carrier testing to have been performed on 267 individuals, of which 123 were CDH1 mutation positive. Prophylactic gastrectomies were performed on 14 families involving 50 individuals. Occult cancer was diagnosed in 31 (31/39=79.5%; results are pending on the remaining 11), based upon pathology and verbal reports. Five individuals underwent prophylactic gastrectomy prior to genetic counseling, 3 of whom later tested negative for mutations. In one of these remarkable HDGC families, 11 first cousins who tested positive for the CDH1 mutation underwent prophylactic total gastrectomy. On a post-surgery questionnaire, they each stated that the decision for the prophylactic procedure was the “right one” for them. In each case, a parent had died of HDGC sequelae, adding to the cousins’ acceptance of DNA testing and surgery. They considered their post-operative nutritional programs to have been acceptable. Conclusion: HDGC and its life-threatening sequelae were significantly ameliorated in CDH1 mutation carriers through total prophylactic gastrectomy in patients at enormous lifetime risk for HDGC. Decision for mutation testing and surgery may be more acceptable through intensive education in concert with a compassionate management team.

No significant financial relationships to disclose.

Characterization of pre- and post-treatment pathology after enzyme replacement therapy for Pompe disease

In Pompe disease, a genetic deficiency of lysosomal acid alpha-glucosidase, glycogen accumulates abnormally in the lysosomes of skeletal, cardiac and smooth muscle, and contributes to clinically progressive and debilitating muscle weakness. The present study involved 8 infantile-onset Pompe patients, treated weekly with 10 mg/kg of recombinant human acid alpha-glucosidase (rhGAA). Muscle biopsies were obtained at baseline, 12 and 52 weeks post-treatment to establish an indicator of efficacy. Several histologic strategies were employed to characterize changes in pre- and post-treatment samples, including high-resolution light microscopy and digital histomorphometry, electron microscopy, capillary density and fiber type analysis, and confocal microscopy for satellite cell activation analysis. Histomorphometric analysis was performed on muscle samples to assess glycogen depletion in response to enzyme replacement therapy (ERT). The extent of glycogen clearance varied widely among these patient samples, and correlated well with clinical outcome. Low glycogen levels, mild ultrastructural damage, a high proportion of type I fibers, and young age at baseline were all features associated with good histologic response. There was no correlation between capillary density and glycogen clearance, and activated satellite cell levels were shown to be higher in post-treatment biopsies with poor histologic responses. This histopathologic study of infantile Pompe disease provides detailed insight into the cellular progression of the disease and its response to therapy while highlighting a number of methodologies which may be employed to assess regression or progression of the associated pathology. As enzyme replacement therapy becomes more prevalent for the treatment of lysosomal storage diseases, such evaluation of post-treatment pathology will likely become a more common occurrence in the daily practice of pathologists.

Recycling of construction and demolition waste materials: a chemical-mineralogical appraisal

Building activity is currently demanding remarkable amounts of inert materials (such as gravel and sand) that are usually provided by alluvial sediments. The EU directives and Italian Legislation are encouraging the re-use of construction and demolition waste provided by continuous urban redevelopment. The re-utilisation of building waste is a relatively new issue for Italy: unfortunately the employment of recycled inert materials is still limited to general bulk and drainage fills, while a more complete re-evaluation is generally hampered by the lack of suitable recycling plants. In this paper, chemical-mineralogical characterization of recycled inert materials was carried out after preliminary crushing and grain-size sorting. XRF and XRD analysis of the different grain-size classes allowed us to recognise particular granulometric classes that can be re-utilised as first-order material in the building activity. Specifically, the presented chemical-mineralogical appraisal indicates that the recycled grain-size fraction 0.6-0.125 mm could be directly re-employed in the preparation of new mortar and concrete, while finer fractions could be considered as components for industrial processing in the preparation of cements and bricks/tiles.

Incidence and evaluation of an AGUS Papanicolaou smear in primary care

BACKGROUND

The category atypical glandular cells of undetermined significance (AGUS) occurs in about 0.5% of Papanicolaou smears. Although recent case series report a great many dysplastic, cancerous, and precancerous lesions of the cervix and endometrium associated with AGUS, little attention has been focused on this issue in primary care literature.

METHODS

We report a case series of 52 women with AGUS Papanicolaou smears in a family health center during 2 years (1997 to 1998), along with colposcopy and biopsy results and 18 months of follow-up findings. These results were compared with findings of recent reports.

RESULTS

The incidence of AGUS was 0.5%, 52 of 10,564 Papanicolaou smears. Colposcopy was performed in 45. Biopsy (n = 46) showed 2 adenocarcinomas of the endometrium, and 6 high-grade dysplastic lesions, including 1 squamous cell carcinoma in situ. Nineteen women had cervical intraepithelial neoplasia stage I-changes of human papillomavirus effect, and 4 had endocervical polyps. Three women were lost to follow-up. The frequency of dysplastic and cancerous lesions in our population (17.4%) is consistent with series findings from cytology and obstetrics and gynecology literature, reporting that 19.5% of women with AGUS have either cancer--adenocarcinoma of the endometrium, squamous cell carcinoma, or extrauterine (8%)--or high-grade lesions--cervical intraepithelial neoplasia II-III, carcinoma in situ, or cervical adenocarcinoma in situ, (11.5%).

CONCLUSIONS

A relatively large percentage of women with AGUS on Papanicolaou smears have cancerous and dysplastic squamous and glandular lesions of the exocervix, endocervix, and endometrium. Clinical practice guidelines recommend patients with AGUS should be evaluated with colposcopy and endocervical curettage. Consensus supports endometrial sampling in women 35 years and older and in those with a laboratory report of AGUS, favors neoplasia or suggests an endometrial source.

Enhanced proliferation and differentiation of human articular chondrocytes when seeded at low cell densities in alginate in vitro

Dedifferentiated human articular chondrocytes exhibited a wide variation in their capacity to proliferate and redifferentiate in an alginate suspension culture system. The greatest extent of proliferation and redifferentiation was seen to be dependent on the formation of clonal populations of chondrocytes and correlated inversely with the initial cell seeding density. Redifferentiating chondrocytes seeded at low density (1 x 10(4) cells/ml alginate) compared with chondrocytes that were seeded at high density (1 x 10(6) cells/ml alginate) showed a nearly 3-fold higher median increase in cell number. a 19-fold greater level of type-II collagen mRNA expression, a 4-fold greater level of aggrecan mRNA expression, and a 6-fold greater level of sulfated glycosaminoglycan deposition at 4 weeks of culture. Matrix molecules from low-density cultures were assembled into chondrocyte-encapsulated, spherical extracellular matrices that were readily visualized in sections from 12-week cultures stained with antibodies against types I and II collagen and aggrecan. Ultrastructural analysis of 12-week low-density cultures confirmed the presence of thin collagen fibrils throughout the matrix.

Purification and characterization of a lipoxygenase enzyme from durum wheat semolina

Purification of a lipoxygenase enzyme from the cultivar Tresor of durum wheat semolina (Triticum turgidum var. durum Desf) was reinvestigated furnishing a new procedure. The 895-fold purified homogeneous enzyme showed a monomeric structure with a molecular mass of 95 +/- 5 kDa. Among the substrates tested, linoleic acid showed the highest k(cat)/K(m) value; a beta-carotene bleaching activity was also detected. The enzyme optimal activity was at pH 6. 8 on linoleic acid as substrate and at pH 5.2 for the bleaching activity on beta-carotene, both assayed at 25 degrees C. The dependence of lipoxygenase activity on temperature showed a maximum at 40 degrees C for linoleic acid and at 60 degrees C for bleaching activity on beta-carotene. The amino acid composition showed the presence of only one tryptophan residue per monomer. Far-UV circular dichroism studies carried out at 25 degrees C in acidic, neutral, and basic regions revealed that the protein possesses a secondary structure content with a high percentage of alpha- and beta-structures. Near-UV circular dichroism, at 25 degrees C and at the same pH values, pointed out a strong perturbation of the tertiary structure in the acidic and basic regions compared to the neutral pH condition. Moreover, far-UV CD spectra studying the effects of the temperature on alpha-helix content revealed that the melting point of the alpha-helix is at 60 degrees C at pH 5.0, whereas it was at 50 degrees C at pH 6.8 and 9.0. The NH(2)-terminal sequence allowed a homology comparison with other lipoxygenase sequences from mammalian and vegetable sources.

Functional and structural properties of the homogeneous beta-glycosidase from the extreme thermoacidophilic archaeon sulfolobus solfataricus expressed in Saccharomyces cerevisiae

A protein with beta-glycosidase activity from Sulfolobus solfataricus (S beta gly) was expressed in the yeast Saccharomyces cerevisiae. The purification procedure was made fast and easy by employing a single chromatographic step. After 5.8-fold purification, the cell extract gave a homogeneous enzyme at 166 U/mg. The recombinant enzyme was functionally and structurally similar to the wild-type enzyme. Kinetic experiments showed the same wide substrate specificity; in fact, the expressed enzyme hydrolyzed beta-D-gluco-, fuco-, and galactosides and a large number of glucoside dimers and oligomers, linked beta 1 -> 4. Moreover, the molecular mass of the enzyme was estimated to be 60 kDa by SDS-PAGE and 240 kDa by gel filtration, glycerol gradient, and ultracentrifugation analyses, indicating that the enzyme has a tetrameric structure. The N-terminal amino acid sequence, the temperature dependent activity, and content of secondary structure were similar to those of the wild-type enzyme. CD spectral and kinetic analyses showed that the only differences from the wild-type enzyme consist of the absence of lysine methylation, the presence of some glycosylated amino acid residues, and lower thermostability. Furthermore, calorimetric analyses on the expressed protein indicated values of delta dH = 5072 kJ/ mol and delta (d)C(p)= 100 kJ/mol, appreciably lower than those of the wild-type protein.

Expression and extensive characterization of a beta-glycosidase from the extreme thermoacidophilic archaeon Sulfolobus solfataricus in Escherichia coli: authenticity of the recombinant enzyme

The gene coding for the beta-glycosidase from the archaeon Sulfolobus solfataricus has been overexpressed in Escherichia coli. The enzyme was purified to homogeneity with a rapid purification procedure employing a thermal precipitation as a crucial step. The final yield was 64% and the purification from the thermal precipitation was 5.4-fold. The expressed enzyme shows the same molecular mass, thermophilicity, thermal stability, and broad substrate specificity, with noticeable exocellobiase (glucan 1,4-beta-D-glucosidase) activity, of the enzyme purified from S. Solfataricus. We provide evidence that the beta-glycosidase can assume its functional state in E. coli without the contribution of N-epsilon-methylated lysine residues.

Delivery of purified, functional CFTR to epithelial cells in vitro using influenza hemagglutinin

To assess the feasibility of protein replacement as a potential therapy for cystic fibrosis, we have evaluated the ability of influenza hemagglutinin (HA) to mediate the delivery of purified cystic fibrosis transmembrane conductance regulator (CFTR) to recipient cells in vitro. CFTR was purified from both CHO cells and Sf9 cells and reconstituted into two different types of vesicular delivery vehicles. In one, CFTR and HA were co-reconstituted into the same lipid vesicle. After binding to the cell surface, delivery of CFTR to the recipient cell was achieved by a transient, low-pH activation of the fusion activity of HA. A second delivery strategy used HA virosomes together with purified CFTR that had been reconstituted into vesicles containing gangliosides, a receptor for HA. After binding of the HA virosomes and CFTR-containing vesicles to the recipient cells, delivery to the plasma membrane again was achieved by a transient pH drop. Delivery of functional CFTR was assessed using the SPQ fluorescence assay. Functional CFTR was detected in a fraction (> 20%) of the recipient cells using this assay. Quantitative binding and fusion assays using radiolabeled virosomes and lipid vesicles showed that on the order of 1,000 of the added CFTR-containing vesicles bound to each C127 cell under the conditions of our delivery protocols. However, only a fraction of these vesicles fused and delivered CFTR to the cell plasma membrane. The two delivery strategies were found to be approximately equivalent in their ability to deliver active CFTR, and there were no significant differences between deliveries using purified CFTR from either cell source. These feasibility studies suggest that purified CFTR can be delivered to a recipient cell in a functional form and therefore represent a significant step in establishing the concept of protein replacement as a therapy for cystic fibrosis.

Interaction of the high-affinity inhibitor tetrahydro-dUMP with the allosteric enzyme deoxycytidylate aminohydrolase

Tetrahydro-dUMP, an analog of the putative transition state in aminohydrolysis of deoxycytidine monophosphate (dCMP) inhibits the allosteric enzyme deoxycytidylate aminohydrolase with high affinity. The inhibition is reversible, and its kinetics is consistent with the analog binding at the substrate site only to one and the same conformation that binds the substrate dCMP. Such kinetics is what would be expected for a transition state analog interacting in an allosteric "K system."

Single-dose oral ciprofloxacin plus parenteral metronidazole for perioperative antibiotic prophylaxis in colorectal surgery

From 1983 until 1990 our standard antibiotic prophylaxis in colorectal surgery has been 80 mg gentamicin plus 500 mg metronidazole, both administered intravenously at the beginning of anesthesia, and then 80 mg gentamicin every 8 h for 3 days. In this time period, 718 patients undergoing elective colorectal surgery by abdominal approach were treated with this prophylactic procedure. The mean wound infection rate was 13.4% with no significant differences between years. In the present study, including 100 adult patients, intravenous gentamicin has been replaced by a single oral dose of 750 mg ciprofloxacin randomly administered 1, 2 or 3 h (+/- 30 min) before anesthesia. All other procedures remained unchanged including intravenous metronidazole. In order to correlate an eventual infection with the actual tissue concentrations during surgery, samples of colon, peritoneum, muscle, subcutaneous fat and skin were obtained from all patients and assayed by HPLC. In only 3 cases (3% of them casuistic) was a wound infection observed, 2 of minor importance and 1 case with wound dehiscence. This infection rate is significantly lower than 13.4% obtained with our previous standard regimen, and lower than the 9% wound infection rate considered to be the 'gold standard' for elective colon resections. The effective ciprofloxacin concentrations in tissues were usually notably higher than the MICs of the pathogens commonly observed in surgical infections of colorectal surgery. By far the highest ciprofloxacin concentrations were observed in colon tissue which may explain the absence of anastomotic dehiscence or peritoneal sepsis in our series.(ABSTRACT TRUNCATED AT 250 WORDS)

Exo-glucosidase activity and substrate specificity of the beta-glycosidase isolated from the extreme thermophile Sulfolobus solfataricus

The enzyme with beta-galactosidase activity from Sulfolobus solfataricus strain MT-4, like other enzymes of this type isolated from thermophilic sources, has broad specificity for beta-D-gluco-, fuco- and galacto-sides. The beta-galactosidase activity was purified by a new procedure that improved yields (44%) and final specific activity (182 units mg-1 at 75 degrees C using chromogenic beta-D-galactoside as substrate). The enzyme hydrolysed a large number of beta-linked glycoside dimers and oligomers; chromogenic beta-glucosides and beta-fucosides are the preferred substrates, and kinetic analysis indicated that they bind to a common catalytic site. The order of catalytic efficiency was beta 1-3 > beta 1-4 > beta 1-6 and cellotetraose > cellotriose > cellobiose for glucose dimers and oliogomers respectively. The cleavage occurred at the non-reducing end of the oligosaccharide, and the enzyme showed noticeable specificity also for the aglycone part of substrates. From these results the enzyme from S. solfataricus strain MT-4 is defined as a true glycosyl hydrolase with remarkable exo-glucosidase activity and it is designated S beta-gly.

Hill coefficient ratios give binding ratios of allosteric enzyme effectors; inhibition, activation, and squatting in deoxycytidylate aminohydrolase (EC 3.5.4.12)

The ratio of the steady-state kinetic Hill coefficients of two different effectors equals (under some rather weak general assumptions) the ratio in which the effectors displace each other from an enzyme. This principle can make implications of experimental allosteric enzyme kinetic data immediately apparent. We can use it to find that one molecule of the allosteric inhibitor of dCMP aminohydrolase, at moderately high effector concentrations, displaces one molecule of substrate, or one molecule of activator, whereas at very high concentrations, one molecule of inhibitor displaces two of substrate. Further use of the principle suggests that substrate, at high concentrations, binds binds to activator sites. However, ratios of substrate, activator, and inhibitor Hill coefficients are incompatible with a simple model of activation in which substrate and activator are bound to the same conformation.

Allosteric modifier and substrate binding of donkey deoxycytidylate aminohydrolase (EC 3.5.4.12)

The hexameric allosteric enzyme deoxycytidylate aminohydrolase from donkey spleen is shown by equilibrium dialysis to bind specifically the allosteric inhibitor, dTTP, the activator dCTP, and the substrate analog dAMP each at six sites (the dTTP and dCTP sites may or may not be identical). These conclusions contrast with earlier ones that there were four sites for each effector; reasons for the discrepancy are discussed. With the knowledge of site numbers and the kinetic information from the accompanying paper it is concluded that the kinetic cooperativity of the enzyme excludes a concerted conformational transition mechanism. Amino acid analysis gives a molecular weight of 18,842 Da per subunit, i.e., 113,052 for the hexamer. A new simplified purification of homogeneous enzyme from donkey spleen probably useful for dCMP aminohydrolase from other sources is described.

Kinetic interaction of 5-AZA-2'-deoxycytidine-5'-monophosphate and its 5'-triphosphate with deoxycytidylate deaminase

5-AZA-2'-deoxycytidine-5'-monophosphate (5-AZA-dCMP) was tested as a substrate, and 5-aza-2'-deoxycytidine-5'-triphosphate (5-AZA-dCTP) was tested as an allosteric effector of purified spleen dCMP deaminase. Graphic analysis of the velocity of deamination of 5-AZA-dCMP versus its concentration gave a hyperbolic curve in which the estimated apparent Km was 0.1 mM. Since this curve was not sigmoidal and 5-AZA-dCMP at low concentrations stimulated the rate of deamination of the natural substrate, dCMP, it was proposed that the binding of 5-AZA-dCMP to the allosteric enzyme dCMP deaminase induced the R form. At substrate saturation, the rate of deamination of dCMP was 100-fold greater than that of 5-AZA-dCMP. dTTP inhibited the deamination of 5-AZA-dCMP with first-order kinetics. This inhibition was reversed by either 5-AZA-dCTP or dCTP. However, dCTP alone produced only a weak activation of the deamination of 5-AZA-dCMP in comparison to the potent activation when dCMP was the substrate. 5-AZA-dCTP was just as effective as dCTP for the allosteric activation of the deamination of dCMP. These results indicate that dCMP deaminase can play an important role in the metabolism 5-aza-2'-deoxycytidine nucleotides and may possibly modulate some of the pharmacological activity of this antimetabolite.

Analysis of competition for substrate sites in an allosteric enzyme with co-operative kinetics. Effects of dAMP and dUMP on donkey spleen deoxycytidylate aminohydrolase

Hypotheses about the interactions of effectors with conformations of allosteric enzymes having co-operative kinetics can be tested simply and exactly without knowledge of the nature of the intersubunit co-operativity by using a linkage approach to the analysis of steady-state kinetics. Applying this approach to competition for substrate sites in the allosteric enzyme donkey spleen dCMP aminohydrolase, we show that the kinetics are consistent with the hypothesis that the substrate dCMP and the competitor dAMP, as well as the allosteric activator dCTP, bind exclusively to the same conformation of the enzyme subunits. The linkage test can be applied in the presence of other effectors without knowledge of how these interact with the enzyme. Our tests showed that dCMP and DAMP are still bound exclusively to this same conformation in the presence of the product dUMP or of the allosteric inhibitor dTTP. We give evidence that dUMP binds to the same conformation as dCMP, but that it is also bound to other conformation(s). The advantages of the linkage approach, and some general problems in steady-state kinetics of allosteric enzymes, are discussed.

Isolation and characterization of the lipid-containing interstitial cell from the developing rat lung

A lipid-containing interstitial cell (LIC) appears in the walls of alveoli during the period of postnatal lung growth associated with the formation of gas exchange surfaces. This cell has been isolated from the 10-day neonatal rat lung by digesting the lung with trypsin and collagenase and using a 6 per cent metrizamide discontinuous density gradient. 5.0 +/- 0.4 x 10(6) LIC per gm. of lung wet weight were isolated at 10 days. At this age, triglycerides accounted for 65 per cent of the LIC lipid with 62 per cent of the triglyceride fatty acids being unsaturated. Linoleic acid was a prominent triglyceride moiety. Density profiles of LIC isolated from 4-, 7-, 12-, 16-, and 21-day neonatal rats, using 0 to 10 per cent metrizamide continuous density gradients, revealed a 2-fold increase in LIC numbers between 4 and 7 days, after which LIC numbers decreased linearly until few LIC were observed at the age of weaning. Mean LIC density decreased from 1.045 gm. per cu. cm. at 4 days to 1.036 gm. per cu. cm. at 12 days, but thereafter increased to 1.050 gm. per cu. cm. at 21 days suggesting accumulation and dissipation of cytoplasmic lipid by LIC during the period of lung growth in which alveoli form. Although the origin, role, and fate of the LIC and its lipid are uncertain, the unique time of appearance of this distinct interstitial cell suggests that it is involved in alveolar formation and lung restructuring during early postnatal lung development.

Postnatal formation of alveoli: interstitial events and physiologic consequences

This paper details some of the interstitial events associated with the formation of alveoli during early postnatal life and the physiological consequences of alterations in this process. Formation of alveoli coincides with differentiation of dormant interstitial fibroblasts into myofibroblasts within new alveolar buds and lipid-filled fibroblasts at the base of these buds. The myofibroblasts appear to be involved in synthesis and secretion of elastin and perhaps other connective tissue elements. Glycosaminoglycans identified with ruthenium red or tannic acid appear in the extracellular matrix of the buds. The role of the lipid-filled fibroblast is uncertain. Since lung size increases at a greater rate than airway size during the early postnatal period, conditions that stimulate or depress postnatal lung alveolarization influence relative airflow rates. Highland natives have larger than normal lungs and low relative maximal expiratory airflow. Hamsters whose growth has been blunted by protein malnutrition have small lungs but large relative maximal expiratory airflow. These results illustrate the physiological importance of dysanaptic lung growth.

Ultrastructure of developing alveoli. I. The role of the interstitial fibroblast

We examined the ultrastructural features of postnatal alveolar septal formation in rats from birth to 28 days of age. At birth, the rat lung consists of large saccules with thick walls and cellular interstitium. Interstitial cells have large oval nuclei with scant cytoplasm containing few organelles and scattered lipid droplets. These cells appear to be poorly differentiated mesenchymal cells not engaged in active protein synthesis or secretion. Between 5 and 15 days of age, saccule walls thin and many new alveolar septa form. Two types of interstitial fibroblasts are present: one which appears at the tips of newly formed septa has the characteristics of a myofibroblast and appears to be engaged in synthesis and secretion of elastin; the other fibroblast appears at the base of new septa, is filled with lipid and contains few other cytoplasmic organelles. After 15 days of age, alveolar walls become thinner, few new septa form and interstitial fibroblasts begin to resemble the dormant type of fibroblasts seen at birth. Thus, the process of postnatal alveolarization of lung parenchyma involves differentiation of the interstitial fibroblast and elastogenesis. The factors which control this process, the precise role of elastogenesis in alveolar septal formation, the origin and fate of the lipid filled fibroblast and the ultimate fate of the myofibroblast remain to be determined.