Enhanced SARS-CoV-2 case prediction using public health data and machine learning models

Objectives

The goal of this study is to propose and test a scalable framework for machine learning (ML) algorithms to predict near-term severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases by incorporating and evaluating the impact of real-time dynamic public health data.

Materials and Methods

Data used in this study include patient-level results, procurement, and location information of all SARS-CoV-2 tests reported in West Virginia as part of their mandatory reporting system from January 2021 to March 2022. We propose a method for incorporating and comparing widely available public health metrics inside of a ML framework, specifically a long-short-term memory network, to forecast SARS-CoV-2 cases across various feature sets.

Results

Our approach provides better prediction of localized case counts and indicates the impact of the dynamic elements of the pandemic on predictions, such as the influence of the mixture of viral variants in the population and variable testing and vaccination rates during various eras of the pandemic.

Discussion

Utilizing real-time public health metrics, including estimated Rt from multiple SARS-CoV-2 variants, vaccination rates, and testing information, provided a significant increase in the accuracy of the model during the Omicron and Delta period, thus providing more precise forecasting of daily case counts at the county level. This work provides insights on the influence of various features on predictive performance in rural and non-rural areas.

Conclusion

Our proposed framework incorporates available public health metrics with operational data on the impact of testing, vaccination, and current viral variant mixtures in the population to provide a foundation for combining dynamic public health metrics and ML models to deliver forecasting and insights in healthcare domains. It also shows the importance of developing and deploying ML frameworks in rural settings.

Predicting increases in COVID-19 incidence to identify locations for targeted testing in West Virginia: A machine learning enhanced approach

During the COVID-19 pandemic, West Virginia developed an aggressive SARS-CoV-2 testing strategy which included utilizing pop-up mobile testing in locations anticipated to have near-term increases in SARS-CoV-2 infections. This study describes and compares two methods for predicting near-term SARS-CoV-2 incidence in West Virginia counties. The first method, Rt Only, is solely based on producing forecasts for each county using the daily instantaneous reproductive numbers, Rt. The second method, ML+Rt, is a machine learning approach that uses a Long Short-Term Memory network to predict the near-term number of cases for each county using epidemiological statistics such as Rt, county population information, and time series trends including information on major holidays, as well as leveraging statewide COVID-19 trends across counties and county population size. Both approaches used daily county-level SARS-CoV-2 incidence data provided by the West Virginia Department Health and Human Resources beginning April 2020. The methods are compared on the accuracy of near-term SARS-CoV-2 increases predictions by county over 17 weeks from January 1, 2021- April 30, 2021. Both methods performed well (correlation between forecasted number of cases and the actual number of cases week over week is 0.872 for the ML+Rt method and 0.867 for the Rt Only method) but differ in performance at various time points. Over the 17-week assessment period, the ML+Rt method outperforms the Rt Only method in identifying larger spikes. Results show that both methods perform adequately in both rural and non-rural predictions. Finally, a detailed discussion on practical issues regarding implementing forecasting models for public health action based on Rt is provided, and the potential for further development of machine learning methods that are enhanced by Rt.

Predicting increases in COVID-19 incidence to identify locations for targeted testing in West Virginia: A machine learning enhanced approach

During the COVID-19 pandemic, West Virginia developed an aggressive SARS-CoV-2 testing strategy which included utilizing pop-up mobile testing in locations anticipated to have near-term increases in SARS-CXoV-2 infections. In this study, we describe and compare two methods for predicting near-term SARS-CoV-2 incidence in West Virginia counties. The first method, R t Only, is solely based on producing forecasts for each county using the daily instantaneous reproductive numbers, R t. The second method, ML+ R t , is a machine learning approach that uses a Long Short-Term Memory network to predict the near-term number of cases for each county using epidemiological statistics such as Rt, county population information, and time series trends including information on major holidays, as well as leveraging statewide COVID-19 trends across counties and county population size. Both approaches used daily county-level SARS-CoV-2 incidence data provided by the West Virginia Department Health and Human Resources beginning April 2020. The methods are compared on the accuracy of near-term SARS-CoV-2 increases predictions by county over 17 weeks from January 1, 2021-April 30, 2021. Both methods performed well (correlation between forecasted number of cases and the actual number of cases week over week is 0.872 for the ML+R t method and 0.867 for the R t Only method) but differ in performance at various time points. Over the 17-week assessment period, the ML+R t method outperforms the R t Only method in identifying larger spikes. We also find that both methods perform adequately in both rural and non-rural predictions. Finally, we provide a detailed discussion on practical issues regarding implementing forecasting models for public health action based on R t , and the potential for further development of machine learning methods that are enhanced by R t.

Environmental fate of 2,4-dinitroanisole (DNAN) and its reduced products

Several defense departments intend to replace 2,4,6-trinitrotoluene (TNT) in munitions formulations by the less sensitive 2,4-dinitroanisole (DNAN). To help understand environmental behavior and ecological risk associated with DNAN we investigated its key initial abiotic and biotic reaction routes and determined relevant physicochemical parameters (pKa, logKow, aqueous solubility (Sw), partition coefficient (Kd)) for the chemical and its products. Reduction of DNAN with either zero valent iron or bacteria regioselectively produced 2-amino-4-nitroanisole (2-ANAN) which, under strict anaerobic conditions, gave 2,4-diaminoanisole (DAAN). Hydrolysis under environmental conditions was insignificant whereas photolysis gave photodegradable intermediates 2-hydroxy-4-nitroanisole and 2,4-dinitrophenol. Physicochemical properties of DNAN and its amino products drastically depended on the type and position of substituent(s) on the aromatic ring. Sw followed the order (TNT<DNAN<2-ANAN<4-ANAN<DAAN) whereas logKow followed the order (DAAN<4-ANAN<2-ANAN<DNAN<TNT). In soil, successive replacement of -NO2 by -NH2 in DNAN enhanced irreversible sorption and reduced bioavailability under oxic conditions. Although DNAN is more soluble than TNT, its lower hydrophobicity and its tendency to form aminoderivatives that sorb irreversibly to soil contribute to make it less toxic than the traditional explosive TNT.

Towards A Fully Automated High-Throughput Phototransfection System

We have designed and implemented a framework for creating a fully automated high-throughput phototransfection system. Integrated image processing, laser target position calculation, and stage movements show a throughput increase of > 23X over the current manual phototransfection method while the potential for even greater throughput improvements (> 110X) is described. A software tool for automated off-line single cell morphological measurements, as well as real-time image segmentation analysis, has also been constructed and shown to be able quantify changes in the cell before and after the process, successfully characterizing them, using metrics such as cell perimeter, area, major and minor axis length, and eccentricity values.

Effect of iron(III), humic acids and anthraquinone-2,6-disulfonate on biodegradation of cyclic nitramines by Clostridium sp. EDB2

AIMS

To determine the biodegradation of cyclic nitramines by an anaerobic marine bacterium, Clostridium sp. EDB2, in the presence of Fe(III), humic acids (HA) and anthraquinone-2,6-disulfonate (AQDS).

METHODS AND RESULTS

An obligate anaerobic bacterium, Clostridium sp. EDB2, degraded RDX and HMX, and produced similar product distribution including nitrite, methylenedinitramine, nitrous oxide, ammonium, formaldehyde, formic acid and carbon dioxide. Carbon (C) and nitrogen (N) mass balance for RDX products were 87% and 82%, respectively, and for HMX were 88% and 74%, respectively. Bacterial growth and biodegradation of RDX and HMX were stimulated in the presence of Fe(III), HA and AQDS suggesting that strain EDB2 utilized Fe(III), HA and AQDS as redox mediators to transfer electrons to cyclic nitramines.

CONCLUSIONS

Strain EDB2 demonstrated a multidimensional approach to degrade RDX and HMX: first, direct degradation of the chemicals; second, indirect degradation by reducing Fe(III) to produce reactive-Fe(II); third, indirect degradation by reducing HA and AQDS which act as electron shuttles to transfer electrons to the cyclic nitramines.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study could be helpful in determining the fate of cyclic nitramine energetic chemicals in the environments rich in Fe(III) and HA.

Production of polyhydroxyalkanoates from methanol by a new methylotrophic bacterium Methylobacterium sp. GW2

A new bacterial strain, isolated from groundwater contaminated with explosives, was characterized as a pink-pigmented facultative methylotroph, affiliated to the genus Methylobacterium. The bacterial isolate designated as strain GW2 was found capable of producing the homopolymer poly-3-hydroxybutyrate (PHB) from various carbon sources such as methanol, ethanol, and succinate. Methanol acted as the best substrate for the production of PHB reaching 40 % w/w dry biomass. PHB accumulation was observed to be a growth-associated process, so that there was no need for two-step fermentation. Optimal growth occurred at 0.5 % (v/v) methanol concentration, and growth was strongly inhibited at alpha concentration above 2 % (v/v). Methylobacterium sp. strain GW2 was also able to accumulate the copolyester poly-3-hydroxybutyrate-poly-3-hydroxyvalerate (PHB/HV) when valeric acid was supplied as an auxiliary carbon source to methanol. After 66 h, a copolymer content of 30 % (w/w) was achieved with a PHB to PHV ratio of 1:2. Biopolymers produced by strain GW2 had an average molecular weight ranging from 229,350 to 233,050 Da for homopolymer PHB and from 362,430 to 411,300 Da for the copolymer PHB/HV.

Metabolism of hexahydro-1,3,5-trinitro-1,3,5-triazine through initial reduction to hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine followed by denitration in Clostridium bifermentans HAW-1

A fast hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)-degrading [28.1 micromol h(-1) g (dry weight) cells(-1); biomass, 0.16 g (dry weight) cells(-1)] and strictly anaerobic bacterial strain, HAW-1, was isolated and identified as Clostridium bifermentans using a 16S-rRNA-based method. Based on initial rates, strain HAW-1 transformed RDX to hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) with yields of 56, 7.3 and 0.2%, respectively. Complete removal of RDX and its nitroso metabolites produced (%, of total C or N) methanol (MeOH, 23%), formaldehyde (HCHO, 7.4%), carbon dioxide (CO2, 3.0%) and nitrous oxide (N2O, 29.5%) as end products. Under the same conditions, strain HAW-1 transformed MNX separately at a rate of 16.9 micromol h(-1) g (dry weight) cells(-1) and produced DNX (25%) and TNX (0.4%) as transient products. Final MNX transformation products were (%, of total C or N) MeOH (21%), HCHO (2.9%), and N2O (17%). Likewise strain HAW-1 degraded TNX at a rate of 7.5 micromol h(-1) g (dry weight) cells(-1 )to MeOH and HCHO. Furthermore, removal of both RDX and MNX produced nitrite (NO2-) as a transient product, but the nitrite release rate from MNX was quicker than from RDX. Thus, the predominant pathway for RDX degradation is based on initial reduction to MNX followed by denitration and decomposition. The continued sequential reduction to DNX and TNX is only a minor route.

Photodegradation of RDX in aqueous solution: a mechanistic probe for biodegradation with Rhodococcus sp

Recently we demonstrated that Rhodococcus sp. strain DN22 degraded hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) (1) aerobically via initial denitration followed by ring cleavage. Using UL 14C-[RDX] and ring labeled 15N-[RDX] approximately 30% of the energetic chemical mineralized (one C atom) and 64% converted to a dead end product that was tentatively identified as 4-nitro-2,4-diaza-butanal (OHCHNCH2NHNO2). To have further insight into the role of initial denitration on RDX decomposition, we photolyzed the energetic chemical at 350 nm and pH 5.5 and monitored the reaction using a combination of analytical techniques. GC/ MS-PCI showed a product with a [M+H] at 176 Da matching a molecular formula of C3H5N5O4 that was tentatively identified as the initially denitrated RDX product pentahydro-3,5-dinitro-1,3,5-triazacyclohex-1-ene (II). LC/MS (ES-) showed that the removal of RDX was accompanied by the formation of two other key products, each showing the same [M-H] at 192 Da matching a molecular formula of C3H7N5O5. The two products were tentatively identified as the carbinol (III) of the enamine (II) and its ring cleavage product O2NNHCH2NNO2CH2NHCHO (IV). Interestingly, the removal of III and IV was accompanied by the formation and accumulation of OHCHNCH2NHNO2 that we detected with strain DN22. At the end of the experiment, which lasted 16 h, we detected the following products HCHO, HCOOH, NH2CHO, N2O, NO2-, and NO3-. Most were also detected during RDX incubation with strain DN22. Finally, we were unable to detect any of RDX nitroso products during both photolysis and incubation with the aerobic bacteria, emphasizing that initial denitration in both cases was responsible for ring cleavage and subsequent decomposition in water.

Detection of explosives and their degradation products in soil environments

Polynitro organic explosives [hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and 2,4,6-trinitrotoluene (TNT)] are typical labile environmental pollutants that can biotransform with soil indigenous microorganisms, photodegrade by sunlight and migrate through subsurface soil to cause groundwater contamination. To be able to determine the type and concentration of explosives and their (bio)transformation products in different soil environments, a comprehensive analytical methodology of sample preparation, separation and detection is thus required. The present paper describes the use of supercritical carbon dioxide (SC-CO2), acetonitrile (MeCN) (US Environmental Protection Agency Method 8330) and solid-phase microextraction (SPME) for the extraction of explosives and their degradation products from various water, soil and plant tissue samples for subsequent analysis by either HPLC-UV, capillary electrophoresis (CE-UV) or GC-MS. Contaminated surface and subsurface soil and groundwater were collected from either a TNT manufacturing facility or an anti-tank firing range. Plant tissue samples were taken fromplants grown in anti-tank firing range soil in a greenhouse experiment. All tested soil and groundwater samples from the former TNT manufacturing plant were found to contain TNT and some of its amino reduced and partially denitrated products. Their concentrations as determined by SPME-GC-MS and LC-UV depended on the location of sampling at the site. In the case of plant tissues, SC-CO2 extraction followed by CE-UV analysis showed only the presence of HMX. The concentrations of HMX (<200 mg/kg) as determined by supercritical fluid extraction (SC-CO2)-CE-UV were comparable to those obtained by MeCN extraction, although the latter technique was found to be more efficient at higher concentrations (>300 mg/kg). Modifiers such as MeCN and water enhanced the SC-CO2 extractability of HMX from plant tissues.

[Not Available]

The paper compares the new results of infant observation and research with the view of the Budapest School of psychoanalysis and some later approaches of the theory of object relations about the early infant development. The author states that the Hungarian psychoanalysis, by focusing on the early object relations, could theoretically describe some phenomena which were empirically validated only later and thereby it could create traditions which can serve as a basis for the child psychotherapy and current mother-infant consultation.

Biotransformation and partial mineralization of the explosive 2,4,6-trinitrotoluene (TNT) by rhizobia

Three strains, T10, B5, and M8, each belonging to a different species of the family Rhizobiaceae and isolated from atrazine-contaminated soils, were tested for their ability to transform 2,4,6-trinitrotoluene (TNT) (50 microg x mL(-1)) in liquid cultures using glucose as the C-source. All three strains were able to transform TNT to hydroxylaminodinitrotoluenes (2-HADNT, 4-HADNT), aminodinitrotoluenes (2-ADNT, 4-ADNT), and diaminonitrotoluene (2,4-DANT). The transformation was significantly faster in the presence of glutamate. Furthermore, the major metabolites that accumulated in cultures were 2-ADNT with glucose, and 4-ADNT with glutamate plus glucose. Rhizobium trifolii T10 was also tested for its ability to transform high levels of TNT (approximately 350 microg x mL(-1)) in a soil slurry. Almost 60% of the TNT was transformed within 2 days in bioaugmented soil slurries, and up to 90% when cultures were supplemented with glucose and glutamate. However, mineralization was minimal in all cases, less than 2% in 78 days. This is the first report on the degradation of TNT by rhizobial strains, and our findings suggest that rhizobia have the potential to play an important role in the safe decontamination of soils and sites contaminated with TNT if bioaugmentation with rhizobia is shown to have no ecotoxicological consequence.

The fate of the cyclic nitramine explosive RDX in natural soil

The sorption-desorption behavior and long-term fate of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was examined in sterilized and nonsterilized topsoil. Results of this study indicate that although RDX is not extensively sorbed by the topsoil (Ks(d) of 0.83 L/kg), sorption is nearly irreversible. Furthermore, there was no difference in the sorption behavior for sterile and nonsterile topsoil. However, over the longterm, RDX completely disappeared within 5 weeks in nonsterile topsoil, and hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) metabolites formed in the aqueous phase. Over the same period, recovery of RDX from sterile topsoil was high (55-99%), and the nitroso metabolites were not detected. Only traces of RDX were mineralized to CO2 and N2O by the indigenous microorganisms in nonsterile topsoil. Of the RDX that was mineralized to N2O, one N originated from the ring and the other from the nitro group substituent, as determined using N15 ring-labeled RDX. However, N2O from RDX represented only 3% of the total N2O that formed from the process of nitrification/denitrification.

Detection of the cyclic nitramine explosives hexahydro-1,3,5-trinitro- 1,3,5-triazine (RDX) and octahydro- 1,3,5,7-tetranitro- 1,3,5,7-tetrazine (HMX) and their degradation products in soil environments

The cyclic nitramine explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX) were examined in field and microcosm soil samples to determine their patterns of degradation and environmental fates. A number of analytical techniques, including solid-phase microextraction with on-fiber derivatization, gas chromatography-mass spectrometry, gas chromatography with electron-capture detection, liquid chromatography-mass spectrometry, and micellar electrokinetic chromatography were required for the analyses. Two different classes of intermediates were detected, both of which lead ultimately to the formation of nitrous oxide (N2O) and carbon dioxide (CO2). The first class was identified as the nitroso derivatives formed by the sequential reduction of -NO2 functional groups. The second class of intermediates, which was favored at higher humidities and in the presence of anaerobic sludge amendments, consisted of ring cleavage products including bis-(hydroxymethyl)-nitramine and methylenedinitramine. Rye-grass (Lolium perenne) present in field samples was found to extract and accumulate HMX from soil without further degradation. In all cases (excepting the plant samples), the indigenous microbes or amended domestic anaerobic sludge consortia degraded the cyclic nitramine explosives eventually to produce N2O and CO2.

Biotransformation routes of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine by municipal anaerobic sludge

Recently we demonstrated that hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a trimer of methylene nitramine (CH2=N-NO2) undergoes spontaneous decomposition following an initial microbial attack using a mixed microbial culture at pH 7 in the presence of glucose as carbon source. The present study describes whether the second cyclic nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), a more strained tetramer of CH2=N-NO2, degrades similarly using sludge of the same source. Part of HMX biotransformed to give products that are tentatively identified as the nitroso derivatives octahydro-1-nitroso-3,5,7-trinitro-1,3,5,7-tetrazocine (mNs-HMX) and octahydro-1,3-dinitroso-5,7-dinitro-1,3,5,7-tetrazocine and its isomer octahydro-1,5-dinitroso-3,7-dinitro-1,3,5,7-tetrazocine (dNs-HMX). Another fraction of HMX biotransformed, apparently via ring cleavage, to produce products that are tentatively identified as methylenedinitramine (O2NNHCH2-NHNO2) and bis(hydroxymethyl)nitramine ((HOCH2)2NNO2). None of the above intermediates accumulated indefinitely; they disappeared to predominantly form nitrous oxide (N2O) and formaldehyde (HCHO). Formaldehyde biotransformed further to eventually produce carbon dioxide (14CO2). Nitrous oxide persisted in HMX microcosms containing glucose but denitrified rapidly to nitrogen in the absence of glucose. The presence of nitrous oxide was accompanied by the presence of appreciable amounts of hydrogen sulfide, a known inhibitor of denitrification.

Microbial degradation of explosives: biotransformation versus mineralization

The nitroaromatic explosive 2,4,6-trinitrotoluene (TNT) is a reactive molecule that biotransforms readily under both aerobic and anaerobic conditions to give aminodinitrotoluenes. The resulting amines biotransform to give several other products, including azo, azoxy, acetyl and phenolic derivatives, leaving the aromatic ring intact. Although some Meisenheimer complexes, initiated by hydride ion attack on the ring, can be formed during TNT biodegradation, little or no mineralization is encountered during bacterial treatment. Also, although the ligninolytic physiological phase and manganese peroxidase system of fungi can cause some TNT mineralization in liquid cultures, little to no mineralization is observed in soil. Therefore, despite more than two decades of intensive research to biodegrade TNT, no biomineralization-based technologies have been successful to date. The non-aromatic cyclic nitramine explosives hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) lack the electronic stability enjoyed by TNT or its transformed products. Predictably, a successful enzymatic change on one of the N-NO2 or C-H bonds of the cyclic nitramine would lead to a ring cleavage because the inner C-N bonds in RDX become very weak (<2 kcal/mol). Recently this hypothesis was tested and proved feasible, when RDX produced high amounts of carbon dioxide and nitrous oxide following its treatment with either municipal anaerobic sludge or the fungus Phanaerocheate chrysosporium. Research aimed at the discovery of new microorganisms and enzymes capable of mineralizing energetic chemicals and/or enhancing irreversible binding (immobilization) of their products to soil is presently receiving considerable attention from the scientific community.

Characterization of metabolites during biodegradation of hexahydro-1, 3,5-trinitro-1,3,5-triazine (RDX) with municipal anaerobic sludge

The biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in liquid cultures with municipal anaerobic sludge showed that at least two degradation routes were involved in the disappearance of the cyclic nitramine. In one route, RDX was reduced to give the familiar nitroso derivatives hexahydro-1-nitroso-3,5-dinitro-1,3, 5-triazine (MNX) and hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX). In the second route, two novel metabolites, methylenedinitramine [(O(2)NNH)(2)CH(2)] and bis(hydroxymethyl)nitramine [(HOCH(2))(2)NNO(2)], formed and were presumed to be ring cleavage products produced by enzymatic hydrolysis of the inner C---N bonds of RDX. None of the above metabolites accumulated in the system, and they disappeared to produce nitrous oxide (N(2)O) as a nitrogen-containing end product and formaldehyde (HCHO), methanol (MeOH), and formic acid (HCOOH) that in turn disappeared to produce CH(4) and CO(2) as carbon-containing end products.

Tissue biocompatibility of a new caprolactone-coated self-reinforced self-expandable poly-L-lactic acid bioabsorbable urethral stent

BACKGROUND AND PURPOSE

The bioabsorption time as well as other properties of bioabsorbable polymers can be affected by the choice of the basic molecule, by the degree of its polymerization, and by the coating material used in the device. The aim of our present study was to evaluate the biocompatibility of a new caprolactone copolymer-coated, self-reinforced poly-L-lactic acid (SR-PLLA) urethral stent by means of a rabbit muscle implantation test. This new material has previously been tested for cytotoxicity using the thymidine incorporation method (DNA synthesis inhibition test), no toxicity being evidenced.

MATERIALS AND METHODS

Fifteen male rabbits were used as experimental animals. Rods made from pure lactic acid, pure caprolactone copolymer, and caprolactone-coated lactic acid were placed on both sides of the dorsal muscles, eight implants per rabbit. Rods made from latex and silicone were used as positive and negative controls, respectively. The animals were sacrificed after 1 week, 1 month, or 6 months. Tissue reactions around the implants were analyzed and scored semiquantitatively.

RESULTS

Acute tissue reactions attributable to operative trauma were seen in all specimens at 1 week. After 6 months, chronic inflammatory changes and foreign-body reactions were seen only in the positive controls.

CONCLUSION

The new caprolactone copolymer material is highly biocompatible.

Biotransformation of 2,4,6-trinitrotoluene with Phanerochaete chrysosporium in agitated cultures at pH 4.5

The biotransformation of 2,4,6-trinitrotoluene (TNT) (175 microM) by Phanerochaete chrysosporium with molasses and citric acid at pH 4.5 was studied. In less than 2 weeks, TNT disappeared completely, but mineralization (liberated 14CO2) did not exceed 1%. A time study revealed the presence of several intermediates, marked by the initial formation of two monohydroxylaminodinitrotoluenes (2- and 4-HADNT) followed by their successive transformation to several other products, including monoaminodinitrotoluenes (ADNT). A group of nine acylated intermediates were also detected. They included 2-N-acetylamido-4,6-dinitrotoluene and its p isomer, 2-formylamido-4, 6-dinitrotoluene and its p isomer (as acylated ADNT), 4-N-acetylamino-2-amino-6-nitrotoluene and 4-N-formylamido-2-amino-6-nitrotoluene (as acetylated DANT), 4-N-acetylhydroxy-2,6-dinitrotoluene and 4-N-acetoxy-2, 6-dinitrotoluene (as acetylated HADNT), and finally 4-N-acetylamido-2-hydroxylamino-6-nitrotoluene. Furthermore, a fraction of HADNTs were found to rearrange to their corresponding phenolamines (Bamberger rearrangement), while another group dimerized to azoxytoluenes which in turn transformed to azo compounds and eventually to the corresponding hydrazo derivatives. After 30 days, all of these metabolites, except traces of 4-ADNT and the hydrazo derivatives, disappeared, but mineralization did not exceed 10% even after the incubation period was increased to 120 days. The biotransformation of TNT was accompanied by the appearance of manganese peroxidase (MnP) and lignin-dependent peroxidase (LiP) activities. MnP activity was observed almost immediately after TNT disappearance, which was the period marked by the appearance of the initial metabolites (HADNT and ADNT), whereas the LiP activity was observed after 8 days of incubation, corresponding to the appearance of the acyl derivatives. Both MnP and LiP activities reached their maximum levels (100 and 10 U/liter, respectively) within 10 to 15 days after inoculation.

Characterization of metabolites in the biotransformation of 2,4,6-trinitrotoluene with anaerobic sludge: role of triaminotoluene

The present study describes the biotransformation of 2,4,6-trinitrotoluene (TNT) (220 microM) by using anaerobic sludge (10%, vol/vol) supplemented with molasses (3.3 g/liter). Despite the disappearance of TNT in less than 15 h, roughly 0.1% of TNT was attributed to mineralization (14CO2). A combination of solid-phase microextraction-gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry identified two distinctive cycles in the degradation of TNT. One cycle was responsible for the stepwise reduction of TNT to eventually produce triaminotoluene (TAT) in relatively high yield (160 microM). The other cycle involved TAT and was responsible for the production of azo derivatives, e.g., 2,2',4,4'-tetraamino-6,6'-azotoluene (2,2',4, 4'-TA-6,6'-azoT) and 2,2',6,6'-tetraamino-4,4'-azotoluene (2,2',6, 6'-TA-4,4'-azoT) at pH 7.2. These azo compounds were also detected when TAT was treated with the anaerobic sludge but not with an autoclaved sludge, suggesting the biotic nature of their formation. When the anaerobic conditions in the TAT-containing culture medium were removed by aeration and/or acidification (pH 3), the corresponding phenolic compounds, e.g., hydroxy-diaminotoluenes and dihydroxy-aminotoluenes, were observed at room temperature. Trihydroxytoluene was detected only after heating TAT in water at 100 degrees C. When 13CH3-labeled TNT was used as the N source in the above microcosms, we were unable to detect 13C-labeled p-cresol or [13CH3]toluene, indicating the absence of denitration or deamination in the biodegradation process. The formation and disappearance of TAT were not accompanied by mineralization, suggesting that TAT acted as a dead-end metabolite.

[Pelvic actinomycosis abscess and intrauterine device]

A case of association between IUD and a left tubal actinomycotic abscess is presented. The 45 year old patient was wearing an IUD for five years. The symptomatology was mainly that of pelvic pain with an associated mass in the left iliac fossa. The working diagnosis was that of a digestive tumor or an adnexal mass. The surgical procedure allowed to identify an inflammatory reaction with a pseudotumoral abscess formation in the left fallopian tube. The etiology was confirmed by the pathology and bacteriology reports. Treatment consists in surgical extirpation of the infected structures and long term antibacterial therapy. Actinomycosis is a rare but potentially serious pelvic disease. It may involve various organs and readily takes on the aspect of tumor formation.

Intra-uterine fetal death following maternal varicella infection

The association of varicella and pregnancy is very rare since 90% of women of reproductive age are immune. In the literature, a fetal varicella syndrome has been described characterized by multiple congenital malformations. We report here a case of intrauterine fetal death following maternal varicella at 17 weeks amenorrhea, with virological proof of fetal contamination. Because of the rarity of this association and by the same token of the fetal contamination during maternal varicella, the management during pregnancy rests essentially on a valid ultrasonic surveillance.

[Pregnancy in a rudimentary uterine horn: rupture in the 15th week of amenorrhea]

A case of pregnancy in a rudimentary uterine horn with rupture 15 weeks after the LMP is described. Ultrasonography at the beginning of such a pregnancy should allow the diagnosis of these uterine malformations. Closer monitoring of the pregnancy is necessary because of the seriousness of potential complications. The frequent finding of placenta accreta in such situations is pointed out. Management approaches are described.

1-(β-DIALKYLAMINOETHYL-2-IMIDAZOLIDINETHIONES

A series of 1-(β-dialkylaminoethyl)-2-imidazolidinethiones and their picrates are described. 1-(β-Diethylaminoethyl)-2-methylmercapto-2-imidazoline dihydroiodide combined with benzylamine with the evolution of methyl mercaptan to give 1-(β-diethylaminoethyl)-2-benzylamino-2-imidazoline (III). In a similar reaction β-alanine gave a product whose picrate gave analytical values in agreement with those calculated for the dipicrate of 1-(β-diethylaminoethyl)-5-keto-Δ8-hexahydro-1,4,8-pyrimidazole (IV).