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This study produced a high-accuracy remotely piloted aircraft system (RPAS) imagery classification method for identifying the invasive reed Phragmites australis (Cav.) Trin. Ex Steud subsp. australis using random forest (RF) machine learning. RPAS imagery was collected in the spring and fall of 2019 using a fixed-wing RPAS equipped with a visible spectrum camera (eBee X, S.O.D.A. 3D; senseFly) in Long Point, Ontario, Canada. Imagery was used to produce separate early and late season classifications and a bi-temporal classification which used imagery from both dates. The overall accuracy achieved for each was 97%, 96%, and 91%, respectively. Digital surface models (DSMs) were the most important variable for identifying Phragmites in all classifications due to their greater height when compared to surrounding herbaceous vegetation. The bi-temporal classification, which utilized change in DSM value during the growing season, resulted in an estimated 47.8% new growth of Phragmites and appeared to capture sparse growth better than traditional classification differencing alone. This study highlights the promising use of high-resolution DSMs produced from RPAS imagery to classify invasive Phragmites and monitor within-year patch expansions.

Camera traps are widely used in wildlife research and monitoring, so it is imperative to understand their strengths, limitations, and potential for increasing impact. We investigated a decade of use of wildlife cameras (2012-2022) with a case study on Australian terrestrial vertebrates using a multifaceted approach. We (i) synthesised information from a literature review; (ii) conducted an online questionnaire of 132 professionals; (iii) hosted an in-person workshop of 28 leading experts representing academia, non-governmental organisations (NGOs), and government; and (iv) mapped camera trap usage based on all sources. We predicted that the last decade would have shown: (i) exponentially increasing sampling effort, a continuation of camera usage trends up to 2012; (ii) analytics to have shifted from naive presence/absence and capture rates towards hierarchical modelling that accounts for imperfect detection, thereby improving the quality of outputs and inferences on occupancy, abundance, and density; and (iii) broader research scales in terms of multi-species, multi-site and multi-year studies. However, the results showed that the sampling effort has reached a plateau, with publication rates increasing only modestly. Users reported reaching a saturation point in terms of images that could be processed by humans and time for complex analyses and academic writing. There were strong taxonomic and geographic biases towards medium-large mammals (>500 g) in forests along Australia's southeastern coastlines, reflecting proximity to major cities. Regarding analytical choices, bias-prone indices still accounted for ~50% of outputs and this was consistent across user groups. Multi-species, multi-site and multiple-year studies were rare, largely driven by hesitancy around collaboration and data sharing. There is no widely used repository for wildlife camera images and the Atlas of Living Australia (ALA) is the dominant repository for sharing tabular occurrence records. However, the ALA is presence-only and thus is unsuitable for creating detection histories with absences, inhibiting hierarchical modelling. Workshop discussions identified a pressing need for collaboration to enhance the efficiency, quality and scale of research and management outcomes, leading to the proposal of a Wildlife Observatory of Australia (WildObs). To encourage data standards and sharing, WildObs should (i) promote a metadata collection app; (ii) create a tagged image repository to facilitate artificial intelligence/machine learning (AI/ML) computer vision research in this space; (iii) address the image identification bottleneck via the use of AI/ML-powered image-processing platforms; (iv) create data commons for detection histories that are suitable for hierarchical modelling; and (v) provide capacity building and tools for hierarchical modelling. Our review highlights that while Australia's investments in monitoring biodiversity with cameras position it to be a global leader in this context, realising that potential requires a paradigm shift towards best practices for collecting, curating, sharing and analysing 'Big Data'. Our findings and framework have broad applicability outside Australia to enhance camera usage to meet conservation and management objectives ranging from local to global scales. This review articulates a country/continental observatory approach that is also suitable for international collaborative wildlife research networks., (© 2025 The Author(s). Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.)

Objective: Arkansas Improving Multidisciplinary Pain Care and Treatment (AR-IMPACT) is an interprofessional team that delivers televideo case conferences to help providers optimize treatment of pain using nonopioid, evidence-based therapies. This article assesses AR-IMPACT using the RE-AIM (reach, efficacy, adoption, implementation, maintenance) framework., Design: A cross-sectional study., Setting: Large, academic medical center., Participants: Healthcare providers., Interventions: Televideo case conferences., Main Outcome Measures: Reach was evaluated by the number of participants, professions represented, and counties/states in which providers resided. Efficacy was assessed via a participant evaluation survey. Adoption was evaluated by calculating the number of repeat participants and soliciting information on barriers to adoption of conference recommendations in clinical practice using the participant evaluation survey. Implementation was evaluated by calculating the time and cost burden of the program., Results: Reach was widespread; continuing education (CE) credits have been claimed by 395 providers in 54 of the 75 counties in Arkansas and 18 states outside Arkansas. For efficacy, the majority of providers noted increases in their knowledge due to AR-IMPACT (89.6 percent). Like reach, adoption was also extensive; approximately 42 percent of AR-IMPACT participants attended more than one conference, and close to 56 percent of participants noted no barriers to adopting the changes discussed in the conferences. With implementation, the time requirements for developing a case conference ranged from 2 to 4 hours, and the cost per CE credit was $137, which is on par with other programs., Conclusions: AR-IMPACT was successful, particularly in reach and efficacy. Entities that implement programs similar to AR-IMPACT will likely experience extensive uptake by providers.

Neuromodulators such as monoamines are often expressed in neurons that also release at least one fast-acting neurotransmitter. The release of a combination of transmitters provides both "classical" and "modulatory" signals that could produce diverse and/or complementary effects in associated circuits. Here, we establish that the majority of Drosophila octopamine (OA) neurons are also glutamatergic and identify the individual contributions of each neurotransmitter on sex-specific behaviors. Males without OA display low levels of aggression and high levels of inter-male courtship. Males deficient for dVGLUT solely in OA-glutamate neurons (OGNs) also exhibit a reduction in aggression, but without a concurrent increase in inter-male courtship. Within OGNs, a portion of VMAT and dVGLUT puncta differ in localization suggesting spatial differences in OA signaling. Our findings establish a previously undetermined role for dVGLUT in OA neurons and suggests that glutamate uncouples aggression from OA-dependent courtship-related behavior. These results indicate that dual neurotransmission can increase the efficacy of individual neurotransmitters while maintaining unique functions within a multi-functional social behavior neuronal network., Competing Interests: The authors have declared that no competing interests exist.

A mild and operationally convenient formation of synthetically valuable N-sulfonyl imines from a range of aryl aldehydes by reaction with iminoiodinanes (PhI[double bond, length as m-dash]NZ) and I 2 has been developed. According to mechanistic experiments described within, the reaction is speculated to proceed through an unconventional light-promoted, N-centered radical (NCR) pathway involving a N,N-diiodosulfonamide reactive species. This method not only provides a new pathway toward the production of activated imines, but also serves as an example of a non-traditional means of carbonyl activation via an NCR species.

Reproductive isolation and speciation are driven by the convergence of environmental and genetic variation. The integration of these variation sources is thought to occur through epigenetic marks including DNA methylation. Proteins containing a methyl-CpG-binding domain (MBD) bind methylated DNA and interpret epigenetic marks, providing a dynamic yet evolutionarily adapted cellular output. Here, we report the Drosophila MBD-containing proteins, dMBD-R2 and dMBD2/3, contribute to reproductive isolation and survival behavioral strategies. Drosophila melanogaster males with a reduction in dMBD-R2 specifically in octopamine (OA) neurons exhibit courtship toward divergent interspecies D. virilis and D. yakuba females and a decrease in conspecific mating success. Conspecific male-male courtship is increased between dMBD-R2-deficient males while aggression is reduced. These changes in adaptive behavior are separable as males with a hypermethylated OA neuronal genome exhibited a decrease in aggression without altering male-male courtship. These results suggest Drosophila MBD-containing proteins are required within the OA neural circuitry to inhibit interspecies and conspecific male-male courtship and indicate that the genetically hard-wired neural mechanisms enforcing behavioral reproductive isolation include the interpretation of the epigenome.

Proteins containing a methyl-CpG-binding domain (MBD) bind 5mC and convert the methylation pattern information into appropriate functional cellular states. The correct readout of epigenetic marks is of particular importance in the nervous system where abnormal expression or compromised MBD protein function, can lead to disease and developmental disorders. Recent evidence indicates that the genome of Drosophila melanogaster is methylated and two MBD proteins, dMBD2/3 and dMBD-R2, are present. Are Drosophila MBD proteins required for neuronal function, and as MBD-containing proteins have diverged and evolved, does the MBD domain retain the molecular properties required for conserved cellular function across species? To address these questions, we expressed the human MBD-containing protein, hMeCP2, in distinct amine neurons and quantified functional changes in sleep circuitry output using a high throughput assay in Drosophila. hMeCP2 expression resulted in phase-specific sleep loss and sleep fragmentation with the hMeCP2-mediated sleep deficits requiring an intact MBD domain. Reducing endogenous dMBD2/3 and dMBD-R2 levels also generated sleep fragmentation, with an increase in sleep occurring upon dMBD-R2 reduction. To examine if hMeCP2 and dMBD-R2 are targeting common neuronal functions, we reduced dMBD-R2 levels in combination with hMeCP2 expression and observed a complete rescue of sleep deficits. Furthermore, chromosomal binding experiments indicate MBD-R2 and MeCP2 associate on shared genomic loci. Our results provide the first demonstration that Drosophila MBD-containing family members are required for neuronal function and suggest that the MBD domain retains considerable functional conservation at the whole organism level across species., (© 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.)

A mild and operationally convenient amino-functionalization of a range of tertiary alkyl halides by reaction with iminoiodinanes (PhI[double bond, length as m-dash]NNs) and I2 has been developed. According to the mechanistic experiments described within, the reaction is speculated to proceed through a light-promoted, N-centered radical pathway involving a N,N-diiodosulfonamide reactive species. This method of direct N-incorporation offers an attractive alternative to the production of α-tertiary amines, a synthetically challenging structural class found in a variety of bioactive molecules.

Global Positioning System (GPS) collars have revolutionized the field of spatial ecology, but to date, few primate studies have used them. We fitted a free-ranging, semi-habituated, juvenile male chacma baboon (Papio hamadryas ursinus) with an automatic self-releasing GPS collar and tracked his movements for 359 days. The collar captured 4254 fixes out of 5719 programmed opportunities, a 74.4 % acquisition rate, suggesting that the collar effectively tracked this baboon in a variety of habitat types. Of the data points captured, 73.7 % were three-dimensional fixes, and of these fixes, 66.9 % were highly accurate, having a dilution of precision of less than four. We calculated home range using three protocols with three estimation methods: minimum convex polygon, fixed kernel-density estimation (KDE), and fixed r local convex hull. Using all data points and the 95 % contour, these methods created home range estimations ranging from 10.8 to 23.1 km(2) for this baboon troop. Our results indicate that the KDE output using all data locations most accurately represented our data set, as it created a continuous home range boundary that excluded unused areas and outlying, potentially exploratory data points while including all seven sleeping sites and a movement corridor. However, home range estimations generated from KDE varied from 15.4 to 18.8 km(2) depending on the smoothing parameter used. Our results demonstrated that the ad hoc smoothing parameter selection technique was a better method for our data set than either the least squares cross-validation or biased cross-validation techniques. Our results demonstrate the need for primatologists to develop a standardized reporting method which documents the tool, screening protocol, and smoothing parameter used in the creation of home range estimations in order to make comparisons that are meaningful.

An independent studies programme (ISP) in the basic medical sciences has been developed at the University of Rochester School of Medicine and Dentistry which involves sixteen students as a learning team working with ten medical teachers as a teaching team. The teachers serve as guides to learning rather than as sources of expert information and function as generalists in their educational roles. The programme, which is preferred by some students, has provided an alternative to the lecture-laboratory-conference format of the traditional curriculum. Some of the advantages of such an ISP are discussed and its effectiveness assessed.

One of the most troublesome features of laparoscopy is the establishment of pneumoperitoneum. This report discusses a very simple and direct way of establishing pneumoperitoneum via transfundal puncture.

Continuous virus production is a characteristic of chicken embryo fibroblasts (CEF) infected and transformed by a nondefective Schmidt-Ruppin subgroup A Rous sarcoma virus. This virus production has been examined with particular attention to the amount of newly budded virus which remained cell-associated, and to the amount and degree of viral aggregation at the cell surface and in the fluid tissue culture medium. The total biologically active virus associated with a Schmidt-Ruppin subgroup A Rous sarcoma virus-infected CEF culture was divided almost equally between that portion of virus which was present in the fluid medium and that portion which was cell-associated. Various mechanical and enzymatic methods were used to remove cell-bound virus and to disperse aggregates of virus in the tissue culture medium to assess cell production of virus per hour accurately, which was determined as an average of 16.4 focus-forming units per cell per hour. With appropriate culture conditions, it was found that Schmidt-Ruppin subgroup A Rous sarcoma virus-infected and -transformed CEF replicated faster, could be passaged more times, and grew to higher cell densities than did normal CEF and CEF infected with a subgroup A Rous associated virus. Subgroup A Rous sárcoma virus-infected CEF cloned with much lower efficiency than did subgroup A Rous associated virus-infected CEF or normal CEF. Experiments employing a temperature-sensitive mutant of subgroup A Schmidt-Ruppin Rous sarcoma virus- and Rous associated virus-infected CEF indicated that the poor cloning efficiency of Schmidt-Ruppin subgroup A Rous sarcoma virus infected cells was not due to the constant production of virus but was probably related to some property associated with transformation of the cell by Rous sarcoma virus.

The proteolytic activities of normal, Schmidt-Ruppin Rous sarcoma virus (SR-RSV) transformed, and infected (RAV) chick embryo fibroblasts (CEF) have been measured by a highly sensitive technique using 3H-acetylated haemoglobin as a substrate. When all 3 types of CEF cells were maintained in serumless media, no differences were detected in the amount of pH 3-4 protease activity released into the media over a 24-h period, and only negligible amounts of pH 7-6 proteolytic activity were found. When normal, transformed, and infected cells were maintained in serumless media and later incubated with 3H-acetylate haemoglobin, a significant proteolysis of the haemoglobin, a 6-fold increase compared to the normal CEF cells, was associated only with plates containing SR-RSV-CEF cells. A fluorescent assay for peptides confirmed that SR-RSV-CEF cells have increased cell-associated proteolytic activity. The net surface charge of the transformed CEF cells was unchanged by maintenance in serumless media but the net surface negativity of the normal and RAV-CEF cells was significantly increased by incubation in media minus serum for 24 h. This suggests that normal CEF cells, maintained in media plus serum, have a substance masking their surface charge which is absent from the surface of transformed cells, possibly because of proteolytic degradation.

Urinary incontinence presents a severe social handicap to the patient and a challenge which has taxed the imagination and ingenuity of surgeons for over a century. Restoration of the urethrovesical junction to its normal retropubic intra-abdominal level will usually result in the cure of pure anatomic female stress incontinence. A retropubic approach is utilized in order to provide for identification and mobilization of the urethra, bladder neck, and vagina. Nonabsorbable sutures are used to attach the perivaginal fascia to the pectineal ligament. The operative technique is described in detail. A series of 77 patients who have been followed for up to 3 1/2 years is presented, showing a stress incontinence cure rate of 96.1%.

Neuraminidase activity of Rous sarcoma virus transformed chick embryo fibroblasts (RSV-CEF) was assayed using an exogenous substrate, neuraminlactitol-[3H], and endogenous, cell surface [14C]-N]-acetyl-neuraminic acid. RSV-CEF had higher neuraminidase activity toward both substrates than did chick embryo fibroblasts (CEF) or nontransformed, Rous associated virus infected CEF (RAV-CEF). The total sialic acid content of RSV-CEF was lower than CEF or RAV-CEF, and more of the total sialic acid was accessible to extracellular Clostridium perfringens neuraminidase. Activity of the enzymes synthesizing and degrading the substrate for sialyltransferase, cytidine-5'-monophosphate-N-acetyl-neuraminic acid (CMP-AcNeu) was measured in order to determine whether control of substrate levels for sialyltransferase might contribute to the decreased levels of glycoprotein bound sialic acid. No change in activity of these enzymes was found in RSV-CEF as compared to CEF or RAV-CEF.

The new avian retroviruses UR1 and UR2 were isolated from spontaneous tumors of chickens by cocultivation of tumor material with susceptible chicken embryo fibroblasts. In vitro, UR1 induced formation of small foci of round and fusiform cells. On the other hand, cells infected by UR2 assumed an extremely elongated morphology. In vivo, both viruses induced fibrosarcomas and myxosarcomas with short latencies. Infectivity assays with and without mitomycin C showed that both viruses were defective for replication, but transformed nonproducing cell clones were obtained only with UR1. UR1-infected transformed nonproducing clones did not release particles detectable by reverse transcriptase assays, and fusion of transformed nonproducing cells with quail cells chronically infected with Rous sarcoma virus (a Bryan strain) failed to rescue infectious virus. This suggested that UR1 does not code for functional envelope glycoproteins. In this regard, UR1 appeared to be similar to Fujinami, PRCII, and Y73 viruses. The helper viruses of partially purified stocks of UR1 and UR2 appeared to belong to subgroup A, but these helper viruses were distinguishable from each other, as shown by host range experiments and neutralization tests. Hybridization studies with DNA complementary to the src gene of Rous sarcoma virus and RNAs extracted from both UR1 and UR2 showed no homology between the genomes of the new isolates and the transforming gene of Rous sarcoma virus.

The activity of the sialyl ectotransferase system of normal chick embryo fibroblasts (CEF) and chick embryo fibroblasts transformed with the Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) have been compared. Neuraminidase treatment of the intact cells increased the sialyl ectotransferase system activity of control and transformed cells two to three times. The ectotransferase system activity increased as the pH was decreased from 7.8 to 6.0. The temperature optimum for both systems was 40 degrees C. Approximately 60% of the 14C-sialic acid incorporated at pH 6.5 or above could be removed with neuraminidase. The activity of the transformed cell system with or without neuraminidase treatment was more stimulated by addition of Mn2+ ions, particularly above pH 7.0. This difference in ion sensitivity indicates that a different cell surface phenomenon is being studied after transformation.

The mucosal and systemic immune responses to Campylobacter jejuni were studied in rabbits receiving gastric inoculation with live organisms. A lavage procedure was used to facilitate repeated monitoring of the intestinal immune response to C. jejuni. Immunity to C. jejuni was determined by secondary challenge by using the removable intestinal tie adult rabbit diarrhea (RITARD) model and monitoring for resistance to colonization and bacteremia. Oral-gastric inoculation of normal rabbits produced a transient intestinal colonization without diarrhea. C. jejuni serotypes differed in their ability to colonize the intestines of rabbits and to stimulate primary intestinal and serum antibody responses. Animals previously colonized were resistant to recolonization and the development of bacteremia after homologous challenge by the RITARD procedure but were not resistant to heterologous challenges. Anticampylobacter intestinal and serum IgA titers before this secondary infection were the most reliable predictors of resistance to colonization and bacteremia.

When stained with ruthenium red (RR), chick embryo cells infected with various strains of Rous sarcoma virus (RSV) and with avian leukosis viruses RAV-1 and RAV-3 showed an increase in the layer of acid mucopolysaccharides (AMPS) at their surfaces as compared with uninfected cells. This increase was most prominent in cells infected with the Fujinami strain of RSV. The layer was resistant to digestion with neuraminidase or trypsin but was readily removed by exposure to hyaluronidase. The thickness of this AMPS layer was not correlated with the varying degree of loss of contact inhibition exhibited by cells infected with the different strains of virus. The staining of the cell envelope with a solution of phosphotungstic and chromic acids (PTA-CR) suggested the presence of glycoproteins. The outer surface of the virions showed the same staining as the cell surface with RR and PTA-CR, and the budding virus particle was seen to incorporate the RR layer of the cell into its structure. The RR layers of cells and virions appeared to fuse, as did those between virus particles, suggesting that these layers play a role in the aggregation of virus particles and in their adherence to the surface of the cell.

The analogues of amino acids, beta-2-thienylalanine, ethionine, and 6-methyltryptophane, inhibited the growth of psittacosis virus (6BC) in tissue culture without evidence of serious toxicity for the host cells. Of a number of vitamin analogues tested, only salicyl-beta-alanide inhibited viral multiplication in the absence of toxic effects on the host cells. 6,7-Diethylriboflavin, desoxypyridoxine, and oxythiamine reduced viral growth in concentrations that possessed some toxicity for host tissue. In tolerated amounts, 3-acetylpyridine, pyridine-3-sulfonic acid, pantoyl sulfanilamide, and desthiobiotin did not effect viral multiplication. Sodium malonate inhibited psittacosis virus growth in non-toxic amounts, whereas sodium monofluoroacetate was ineffective. Colchicine suppressed multiplication of virus only after a prolonged period of exposure and subsequent delay before producing inhibition, suggesting that the effect was secondary to its antimitotic action which suppressed multiplication of the host cells.

A new simple method of evaluating specific cytotoxicity to tuberculoprotein in the study of tuberculin hypersensitivity in vitro by comparing cell populations is presented. Utilizing this technic it was possible to reproduce Rich's results (1, 2) using human tissues of reticuloendothelial origin. The demonstration of the specific cytotoxic phenomenon in tuberculin-sensitive human tissues indicates that the principle elaborated by Rich (2) of specific changes in the individual fixed tissue cells in tuberculin hypersensitivity, possibly related to cellular antibodies, applies to human subjects as well as to the animals heretofore studied. Preliminary observations suggest that macrophages from donors with clinically active tuberculosis are more sensitive to tuberculoprotein than macrophages from tuberculin-positive donors without clinically active disease. Macrophages from tuberculin-positive donors appeared to be more sensitive to tuberculoprotein than fibroblasts derived from the same tissue. An inhibition of cell proliferation was seen when both cell types were exposed to PPD. In addition macrophages responded to tuberculoprotein with gross morphological changes and eventual cytolysis.

The relationship between hemagglutination and hemolysis by the mumps virus has been studied under conditions which affect (a) the receptors of chicken red cells and (b) the adsorption and subsequent elution of the virus from these cells. The results show that the hemolytic action of the virus appears to involve some of the same receptor areas of erythrocytes that are implicated in hemagglutination. Materials such as allantoic fluid, egg white, and red cell extract, which inhibit the agglutination of chicken red cells by mumps virus, also interfere with its hemolytic activity. Of these inhibitors, egg white and red cell extract, which are readily destroyed by the virus during incubation at 37 degrees C., exert a greater antagonistic effect on hemagglutination than on hemolysis. Heated mumps virus or unheated influenza virus interferes with the hemolysis of red cells by untreated mumps virus. Though hemolysis takes place during elution of the virus after its adsorption on the red cell, the processes are apparently distinct. The hemolytic activity is easily affected by certain conditions of pH and temperature which have no effect on the ability of mumps virus to adsorb on and elute from red cells.

The inhibitory action of sodium sulfadiazine on the growth of psittacosis virus (6BC) in embryonated eggs is readily reversed by citrovorum factor but not by small amounts of vitamin B(12). In embryonated eggs, the pteroylglutamic acid analogues, 9-methylpteroylglutamic acid and 4-aminopteroylaspartic acid, produced some suppression of the growth of psittacosis virus (6BC). 4-Aminopteroylglutamic add, 4-amino-N(10)-methylpteroylglutamic acid, and 4-aminopteroylaspartic acid inhibited the growth of this virus in tissue cultures at concentrations which were not toxic for the host tissue. The inhibitory action of 4-amino-N(10)-methylpteroylglutamic acid and 4-aminopteroylaspartic acid was readily overcome by addition of citrovorum factor. Growth of meningopneumonitis virus in embryonated eggs or tissue culture is suppressed by 4-aminopteroylaspartic acid. The advantages of the tissue culture technic for studies on the growth of viruses are discussed.

Mouse fibroblasts (L cells) fail to support the growth of psittacosis virus (6BC strain) if they are maintained on a medium containing only inorganic salts and glucose for 2 days prior to infection. Virus propagation can be stimulated by the addition of a synthetic medium containing amino acids, water-soluble vitamins, glutamine, glucose, and inorganic salts. By omitting single amino acids from the complete synthetic medium, tyrosine, threonine, methionine, isoleucine, phenylalanine, tryptophan, leucine, valine, and cysteine or cystine were found to be essential for stimulation, while lysine, arginine, histidine, hydroxyproline, proline, glutamic acid, aspartic acid, serine, alanine, and glycine were not essential. The cells on deficient media showed varying degrees of degenerative changes, but there was little correlation between ability to support psittacosis virus growth and morphologic condition of the cells. Glucose is also an essential component of the medium for viral growth, but the absence of glutamine had no effect on stimulation of virus propagation. L cell cultures maintained on media deficient in phenylalanine or tryptophan for 2 days before infection were also found to be incapable of supporting virus growth. The implications of this study in latent viral infections are discussed.

Using the roller tube method of tissue culture, it has been shown that cortisone and compound F inhibit the cytotoxic action of PPD upon macrophages from the splenic tissue of tuberculous guinea pigs. Pretreatment of the cells for 24 hours with hormones before exposure to PPD was found to be essential. Estrone and desoxycorticosterone glucoside had no protective activity. Certain advantages of the tissue culture method in studies of tuberculin hypersensitivity and possible mechanisms and implications of this protective action of cortisone are discussed.