Air change rates and infection risk in school environments: Monitoring naturally ventilated classrooms in a northern Italian urban context.

The importance of building ventilation in avoiding long-distance airborne transmission has been highlighted with the advent of the COVID-19 pandemics. Among others, school environments, in particular classrooms, present criticalities in the implementation of ventilation strategies and their impact on indoor air quality and risk of contagion. In this work, three naturally ventilated school buildings located in northern Italy have undergone monitoring at the end of the heating season. Environmental parameters, such as CO2 concentration and indoor/outdoor air temperature, have been recorded together with the window opening configurations to develop a two-fold analysis: i) the estimation of real air change rates through the transient mass balance equation method, and ii) the individual infection risk via the Wells-Riley equation. A strong statistical correlation has been found between the air change rates and the windows opening configuration by means of a window-to-volume ratio between the total opening area and the volume of the classroom, which has been used to estimate the individual infection risk. Results show that the European Standard recommendation for air renewal could be achieved by a window opening area of at least 1.5 m2, in the most prevailing Italian classrooms. Furthermore, scenarios in which the infector agent is a teacher show higher individual infection risk than those in which the infector is a student. In addition, the outcomes serve school staff as a reference to ensure adequate ventilation in classrooms and keep the risk of infection under control based on the number of the students and the volume of the classroom.

Ventilation strategies to reduce airborne transmission of viruses in classrooms: A systematic review of scientific literature.

The recent pandemic due to SARS-CoV-2 has brought to light the need for strategies to mitigate contagion between human beings. Apart from hygiene measures and social distancing, air ventilation highly prevents airborne transmission within enclosed spaces. Among others, educational environments become critical in strategic planning to control the spread of pathogens and viruses amongst the population, mainly in cold conditions. In the event of a virus outbreak - such as COVID or influenza - many school classrooms still lack the means to guarantee secure and healthy environments. The present review examines school contexts that implement air ventilation strategies to reduce the risk of contagion between students. The analysed articles present past experiences that use either natural or mechanical systems assessed through mathematical models, numerical models, or full-scale experiments. For naturally ventilated classrooms, the studies highlight the importance of the architectural design of educational spaces and propose strategies for aeration control such as CO2-based control and risk-infection control. When it comes to implementing mechanical ventilation in classrooms, different systems with different airflow patterns are assessed based on their ability to remove airborne pathogens considering parameters like the age of air and the generation of airflow streamlines. Moreover, studies report that programmed mechanical ventilation systems can reduce risk-infection during pandemic events. In addition to providing a systematic picture of scientific studies in the field, the findings of this review can be a valuable reference for school administrators and policymakers to implement the best strategies in their classroom settings towards reducing infection risks.

Microbially-enhanced composting of olive mill solid waste (wet husk): bacterial and fungal community dynamics at industrial pilot and farm level.

Bacterial and fungal community dynamics during microbially-enhanced composting of olive mill solid waste (wet husk), used as a sole raw material, were analysed in a process carried out at industrial pilot and at farm level by the PCR-DGGE profiling of the 16 and 26S rRNA genes. The use of microbial starters enhanced the biotransformation process leading to an earlier and increased level of bacterial diversity. The bacterial community showed a change within 15 days during the first phases of composting. Without microbial starters bacterial biodiversity increased within 60 days. Moreover, the thermophilic phase was characterized by the highest bacterial biodiversity. By contrast, the biodiversity of fungal communities in the piles composted with the starters decreased during the thermophilic phase. The biodiversity of the microbial populations, along with physico-chemical traits, evolved similarly at industrial pilot and farm level, showing different maturation times.

Microbially-enhanced composting of wet olive husks.

The production of a compost from olive wet husks is described. The process is enhanced through the use of starters prepared with virgin husks enriched with selected microbial cultures. This approach, with respect to composting without the use of starters, allows to achieve faster start of the process (10 vs. 45 days), deeper humification (humification rate 19.2 vs. 12.2), shorter maturation time (2 vs. 4-5 months) and better detoxification of the starting material. Furthermore, the compost produced can effectively substitute for turf as a cultivation substrate in horticulture at greenhouse level, with beneficial effects on nutraceutical traits of tomato fruits.

[Canaud central venous catheters: 4-year experience]. / Cateteri venosi centrali di canaud: esperienza di oltre quattro anni.

BACKGROUND: The use of central venous catheters for permanent vascular access has become increasingly important because of the characteristics and the clinical problems of incident patients or patients already undergoing chronic hemodialysis. In this study a short and medium term evaluation was made of a double permanent central venous catheter positioned in the right internal jugular vein. The Canaud catheter was evaluated both from the point of view of practical use and for various technical and clinical problems. METHODS: During the observation period, July 1995 - September 1999, these catheters were used in 39 patients (mean age 72 years), 22 females and 17 males; 31% were diabetic patients and 46% were older than 75 years. Forty-five catheters were positioned with an average dwelltime of 347 days. RESULTS: Utilization was almost immediate and the resulting blood flow was suitable for all depurative techniques (blood flow more than 250 ml/min), with an average recirculation of 11.9% and an average resistance index of 0.54. Among the most serious complications during surgery a respiratory block was observed followed by the complete recovery of the patient. Some clinical complications were noted (5 venous thrombosis), as were some technical ones: 12% well as related to problems with the adapter, 24.3% to reversible thrombosis of the catheters occurred in 23 catheters in 22 patients. Infections. CONCLUSIONS: Overall Canaud catheters appear to represent a valid alternative to other more recent catheters for permanent vascular access. If necessary, they can be easily substituted due to the absence of a subcutaneous cuff.

[Permanent central venous catheters for dialysis. The situation in Piedmont-Aosta Valley]. / Cateteri venosi centrali a permanenza per dialisi. Realtà in Piemonte-Valle d'Aosta.

BACKGROUND: Permanent central venous catheters for hemodialysis have become increasingly important as vascular accesses for extracorporeal dialysis. The aim of this study was to evaluate the prevalence and various aspects of these catheters in the chronic dialysis population in Piedmont and Aosta Valley on 30-6-1998 using a multiple-choice questionnaire. METHODS: A total of 2389 patients were receiving chronic hemodialysis. Permanent central venous catheters were present in 6.2% of the population (149 patients), arteriovenous fistulas in 83.1%, vascular prostheses in 9.3% and temporary catheters in 1.4%. The site chosen for permanent catheters was the internal jugular vein in 88.6% of cases, the subclavian vein in 8.7% of cases and the femoral vein in 2.7% of cases. The double catheter is the most frequently used. In 76% of centres catheters are positioned by nephrologists. Thrombosis prophylaxis is performed in 98% of cases with heparin and the most frequently used disinfectant to dress the cutaneous exit is iodopovidone. RESULTS: This study highlights the important role played by permanent catheters. The double catheter was used in 64.4% of the entire population, confirming the greater efficiency of these catheters as reported in the literature. Operating autonomy is relative in 76.2% of centres where catheters are positioned by nephrologists who often use the collaboration of other specialists. CONCLUSIONS: The authors stress the need to reflect on the use of iodopovidone is to dress the cutaneous exit of catheters since this disinfectant is contraindicated by one of the largest manufacturers of silicone catheters owing to its harmful medium long-term effects.

[Temporary dialysis access in patients with acute renal failure. Protocols of the dialysis centers in the Piedmont and Valled'Aosta]. / Accessi temporanei per dialisi nei pazienti con IRA. Protocolli dei centri dialisi del Piemonte e della Valle d'Aosta.

BACKGROUND: A retrospective study was performed using a multiple-choice questionnaire in order to analyse the normal procedures and trends regarding the insertion and management of emergency dialysis access in patients with acute renal failure in 23 Centres in Piedment and the Aosta Valley, regions in the north of Italy with about 4.5 million inhabitants. METHODS: The observation period ran from January 1996 to July 1997. A questionnaire with 19 main questions and 90 possible multiple answers sent to 22 Centres for adults and the only pediatric centre in both regions. RESULTS: An analysis of the results showed that the most frequently used site in these regions is the subclavian vein (37.8%), followed by the internal jugular vein (32%), the femoral site (28.8%) and peritoneal catheter (1.4%); in pediatric patients, 5% used the femoral site, 10% the subclavian vein, 20% the internal jugular vein and 65% the peritoneal catheter. In 4 centres (18.2%), nephrologists do not position any type ofd access for acute renal failure. In 50% of centres, all doctors insert femoral catheters autonomously. CONCLUSIONS: Some choices, such as the subclavian route, are open to criticism and may perhaps be linked to customary procedures used by anesthetists and intensive care specialists. Some centres only have relative automomy for insertion, and lastly some types of catheters and techniques are not used. The peritoneal catheter has been abandoned by adult centres as an access in acute kidney failure patients.

HIV-risk behaviour and knowledge about HIV/AIDS among patients with schizophrenia.

BACKGROUND: Recent literature has demonstrated that psychiatric patients, particularly those with a diagnosis of schizophrenia, may be at high risk for HIV infection. In fact, HIV-risk behaviour, such as intravenous drug with sharing needles, promiscuity associated with unprotected sex and high-risk sexual activity after using drugs has been reported by a substantial proportion of mentally ill patients. METHODS: In order to examine this problem in Italy, HIV-risk taking behaviour and knowledge about HIV/AIDS was investigated among 91 schizophrenic patients by using two self-report questionnaires (HIV-Risk Behaviour Questionnaire; AIDS-Risk Behaviour Knowledge Test). RESULTS: One-third of the patients reported having been tested for HIV infection and one tested seropositive (prevalence 3.4%). A high proportion of patients reported HIV-risk behaviour, such as injected drugs use (22.4%) and engaging in high risk sexual activity (e.g. multiple partners, 58%; prostitutes, 45%; occasional partners, 37%). Condoms were 'never used' by 41% of the patients and 'almost never used' by another 25%. In spite of these behaviours, 65% reported no concern of HIV infection. Knowledge about AIDS was lower among psychiatric patients than a healthy control group. Patients with long-lasting illness and numerous psychiatric admissions were less acknowledgeable about HIV infection. Certain misconceptions on HIV transmission were related to HIV risk behaviour. CONCLUSIONS: These results indicate the urgent need for HIV educational programmes within mental health community-care settings.

Correlations between bone histopathology and serum biochemistry in uremic patients on chronic hemodialysis.

To define which noninvasive investigations are of value in predicting bone histology, we analyzed transiliac bone specimens (66 biopsies, 14 autopsies) from 80 uremic patients on chronic dialysis. Results were compared with values of different measurements of parathyroid hormone (PTH), alkaline phosphatase (APH), osteocalcin, calcitonin, baseline and post-deferroxamine (DFO) aluminium (Al),--beta 2 microglobulin, ferritin and bone mineral density. Among histomorphometric parameters, woven osteoid, active osteoblastic surface and resorption surface showed the best correlations with dynamic and biochemical marks of active bone metabolism. Among biochemical parameters, intact PTH and APH were better related to histomorphometric and dynamic bone parameters than other PTH measurements as well as osteocalcin, while calcitonin was related to no parameters. Stainable Al alone, and not total bone Al content was related to bone histology. Baseline Al was related to lamellar osteoid, while post-DFO Al was related to stainable Al. beta 2 microglobulin was positively related to active osteoid surface and ferritin was inversely related to the mineral apposition rate, while bone mineral density was related only to total bone volume. We conclude that, though definite diagnosis requires the use of histological methods, few simple biochemical parameters may offer insight to the bone metabolic status, useful to the physician in day to day clinical practice.

[Permanent vascular catheters for extracorporeal dialysis. Preliminary study: Canaud and Tesio catheters]. / Catetere vascolare a permanenza per dialisi extracorporea. Studio preliminare: cateteri di Canaud e Tesio.

The use of alternative permanent vascular accesses has recently become increasingly common. The possibility of using the catheterization of central venous vessels has therefore been taken into consideration, in particular the internal jugular vein. During an observation period of 32 months the catheterization of the internal jugular vein (IJV) was used as a definitive access in 34 patients (12 M, 22 F; mean age 67.5, mean dialytic age 56 months in 18 patients, in 16 patients the insertion was by primary intention). A total of 44 IJV catheters were used, of which 18 Tesio and 26 Canaud. The authors examined the immediate complications following insertion and the episodes occurring during the observation period, including the problem of infection. The insertion of catheters was possible in all cases. In terms of catheter function, blood flow was adequate for the various purifying techniques. No severe complications were reported: gaseous embolism, pneumothorax, hemothorax, hemomediastinum. Infection was observed in 11 patients and 13 catheters, of which 70% were mainly provoked by Staphylococcus aureus and epidermidis. During the observation period there was a drop-out of 14 patients, 11 of whom died (3 following sepsis that failed to respond to antibiotic therapy). This preliminary experiment shows that permanent jugular catheters may be regarded as a valid access for hemodialytic treatment both in patients with severe problems of vascular access and for patients who present a short-term prognosis of dialysis and life expectancy at the time of starting hemodialysis.

[Instantaneous clearances: standard heparin versus low molecular weight heparin]. / Clearances istantanee: eparina standard verso eparine a basso peso molecolare.

Standard heparin is still considered as a reference point for anticoagulation in CEC, although its use is not totally devoid of long-term and short term side effects, considering the risk of hemorrhage that patients undergo during dialysis. Numerous attempts have been made in the search for an alternative anticoagulating method. The recent discovery that low molecular weight fractions (LMWH) of standard heparin (UFH) assure the same antithrombotic effect but with a minor anticoagulating action, points to such a drug as an interesting alternative to the traditional use of heparin during dialysis. Our present task is to evaluate the purifying efficiency of different cuprophan and synthetic membranes with two LMWH and UFH, measuring the instantaneous ureic clearance of different dialysers at the start and end of each dialysis. N. 43 chronic patients were examined whilst undergoing different methods of treatment; using 12 different kinds of membrane, for a total of 22 filters. Every patient underwent a dialysis using each kind of heparin at least once, for a total of 189 dialysis. Neither the initial nor the final ureic clearances, nor the percentage of decreasing had changed by using different types of heparin and membranes with diverse thrombogenicity and ultrafiltration capacities. We may conclude from the results of the tests that the purifying efficiency of small molecules, judging from the istantaneous clearances, do not significant results compared to UFH.

[The value of albumin and cholesterol blood levels as indicators of the risk of death in dialysis. Working Group of the Piedmont Registry of Dialysis and Transplantation]. / Il valore dei livelli di albuminemia e colesterolemia come indicatori del rischio di morte in dialisi. Gruppo di lavoro dell'RPDT.

In recent years, the availability of large epidemiological series allowed identification of biochemical outcome markers in the dialysis population. Interest towards albumin and cholesterol levels is motivated by their easy availability and by the presence of a strong short-term effect on mortality and morbidity. The aim of the study was an analysis of the relationship between albumin and cholesterol levels at start of dialysis and mortality (gross mortality and Kaplan Meier survival curves). Data were obtained from the Piedmont Regional Registry of Dialysis and Transplantation (Northern Italy Region, about 4,400,000 inhab, 20 Dialysis Centers, open acceptance since mid '70, yearly information on 100% of patients) in the period 1981-1990 (4734 patients on file). Only non diabetic patients with follow-up > = 1 month, who started treatment in the Region, were selected. Patients with renal function recovery were excluded. Albumin levels were dichotomized at 3.5 g/dl. Cholesterol was stratified into 3 levels (< 150, 150-250, > or = 300 mg/dl). The choice of dividing the study into 2 periods (1980-1985 vs 1986-1990) is due to the fact that 1984 has been the year of switch from acetate to bicarbonate dialysis. Prevalence of albumin and cholesterol under the normal range (22% and 15%) is low and rises with age and presence of high risk conditions. A a good correlation with the risk of death of these biochemical markers (stronger for albumin at least in the short term) was observed. No correlations are found with risk of death and elevated cholesterol levels (low number of cases).(ABSTRACT TRUNCATED AT 250 WORDS)

[Renal insufficiency due to cholesterol embolism. 4 cases]. / Insufficienza renale da embolia colesterinica. Quattro casi.

Atheroembolic disease is a complication of atheromatous disease and is quite often misunderstood. A precise diagnosis can be made difficult, by the lack of specific tests. The first case, in which we identified this disease, resulted from a bladder biopsy, in the instance of a patient with a suspected carcinoma. The experience, with this initial patient, led us to identification of a further 3 cases, within our previous 2 years case histories. One must consider the possibility of atheroembolic disease during the differential diagnosis of acute renal failure in geriatric patients, given the serious prognosis.

Kinetics of aluminoxamine and feroxamine chelates in dialysis patients.

To achieve a rational basis for the use of deferoxamine (DFO) in aluminum (AL) -and iron (Fe)-overloaded uremic patients, important insights may be provided by the recently available micromethods to determine DFO and its metallochelates aluminoxamine (AlA) and feroxamine (FeA). With this procedure, AlA and FeA plasma kinetics were evaluated in a pilot study in 10 uremic patients during a whole week after a single DFO infusion performed during the first hour of the first standard bicarbonate hemodialysis (HD) of the week. Patients were divided into normal (n = 6) and high (n = 4) ferritin groups (1 and 2 respectively). Baseline Al concentrations were greater than 2 less than 6 in group 1 and less than 1.5 mumol/l in group 2. DFO was given at doses of 40, 20 and 10 mg/kg. AlA and FeA showed substantially different kinetics. AlA kinetics were similar in group 1 and 2: they reached their peak at the beginning of the 2nd HD, decreased during the 2nd and 3rd HD, and with the highest DFO dose still increased between the 2nd and 3rd HD. At similar pre-DFO Al values (greater than 2 less than 3.3 mumol/l), increased DFO doses produced increased AlA concentrations ranging from 95 to 40% of total plasma Al for all the week. At higher pre-DFO Al values (greater than 3.5 less than 6 mumol/l), even a DFO dose as low as 10 mg/kg was sufficient to form consistent AlA amounts (from 80 to 15% of total Al).(ABSTRACT TRUNCATED AT 250 WORDS)

[Weekly dialysis integrated with low-protein diet and essential amino acids. Preliminary data]. / Dialisi monosettimanale integrata con dieta ipoproteica e aminoacidi essenziali. Dati preliminari.

The possibility of applying a once-a-week dialysis programme supplemented with hypoproteic diet as an adequate technique for starting the uraemic patient on dialysis is examined. Thirteen patients have been so treated, 7 of them currently under treatment for a global period of observation of 46 months. At the moment dialysis began, mean glomerular filtrate was 5.14 ml/min. Once-a-week dialytic treatment with bicarbonate dialysis was associated with a hypoproteic diet of 0.5 g/kg/die of proteins, supplemented with essential amino acids. This treatment showed excellent dialytic tolerance, the values of dialysis start blood nitrogen were lower than 200 mg/dl and dialytic efficiency was compatible with a Kt/v greater than 1.1. There was no observation of any subjective or objective symptomatology that could be related to dialytic inadequacy. Taken as a whole these results make it possible to state that this type of approach permits a gradual start to dialysis and deserves further study.