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  • Lymphogranuloma venereum in a pregnant woman.

    Heaton, S; Hammerschlag, M R; Roblin, P M; Di Pasquale, R C (1988-07)
    Lymphogranuloma venereum was diagnosed postpartum in a young black woman, who was a drug abuser. Chlamydia trachomatis was isolated from aspirate of a left inguinal mass, and the patient was also seropositive for human immunodeficiency virus. During hospitalization she was treated with ampicillin, gentamicin, and doxycycline. Her twin infant girls had no evidence of C. trachomatis infection. The mother was discharged from the hospital after partial resolution of the left inguinal mass and was lost to follow-up.
  • Comparison of enzyme immunoassay and culture for diagnosis of chlamydial conjunctivitis and respiratory infections in infants.

    Hammerschlag, M R; Roblin, P M; Cummings, C; Williams, T H; Worku, M; Howard, L V (1987-12)
    The efficacy of Chlamydiazyme (Abbott Laboratories, North Chicago, Ill.) in detecting neonatal conjunctival and respiratory infections caused by Chlamydia trachomatis was determined by comparison of this enzyme immunoassay (EIA) with the method of isolation of chlamydiae in tissue culture. The sensitivity and specificity of Chlamydiazyme for detecting C. trachomatis in conjunctival specimens from infants with conjunctivitis were 98 and 94%, respectively. For nasopharyngeal infection in infants with conjunctivitis, the sensitivity and specificity were 87 and 92%, respectively. There were nine nasopharyngeal specimens that were Chlamydiazyme positive and culture negative. All of these specimens demonstrated the presence of typical fluorescing chlamydial elementary bodies when pellets of the original specimens were examined with a fluorescein-conjugated monoclonal antibody. When the EIA was performed on nasopharyngeal specimens from infants with suspected chlamydial pneumonia, 6 culture-positive and 10 culture-negative specimens were correctly identified.
  • Colonization of sexually abused children with genital mycoplasmas.

    Hammerschlag, M R; Doraiswamy, B; Cox, P; Cummings, M; McCormack, W M (1987-01)
    Although sexually abused children are usually evaluated only for the presence of infections with Neisseria gonorrhoeae and Treponema pallidum, they are also at risk for acquiring other sexually transmitted organisms prevalent in the adult population. Accordingly, we examined pharyngeal, anorectal and genital specimens from 50 children who had been sexually abused and from 40 healthy children who served as controls; these specimens were cultured for Mycoplasma hominis and Ureaplasma urealyticum. M. hominis was isolated from the anorectal and vaginal cultures of 11 (23%) and 16 (34%), respectively, of 47 abused girls as compared with three (8%) and six (17%), respectively, of 36 controls. U. urealyticum was isolated from the anorectal and vaginal cultures of nine (19%) and 14 (30%), respectively, of the abused girls as compared with one (3%) and three (8%), respectively, of 36 controls. Colonization with genital mycoplasmas was not associated with any symptoms.
  • Clinical efficacy and safety of cefmenoxime in children.

    Tansino, G F; Hammerschlag, M R; Congeni, B L; Cox, P A; Doraiswamy, B; duBouchet, L (1985-10)
    Cefmenoxime, an investigational semisynthetic cephalosporin, was evaluated in 18 pediatric patients with a variety of infections. There were seven patients with urinary tract infections, two with wound infections, two with osteomyelitis, two with abscess infections, one with cervical adenitis, one with hidradenitis, one with pneumonia and sepsis, one with periorbital cellulitis, and one with ventriculitis. A total of 16 (88%) patients had a satisfactory clinical response demonstrated by improvement in clinical signs and symptoms. A total of 12 (67%) patients demonstrated eradication of their infecting organisms. Of the pathogens isolated in these patients, 16 isolates were susceptible to cefmenoxime. One patient developed a generalized urticarial rash that resolved within 24 h after cessation of cefmenoxime therapy. Mean peak level in serum after intravenous infusion was 55 micrograms/ml.
  • In vitro activity of a group of broad-spectrum cephalosporins and other beta-lactam antibiotics against Chlamydia trachomatis.

    Hammerschlag, M R; Gleyzer, A (1983-03)
    The activities of seven broad spectrum cephalosporins, four other beta-lactam antibiotics, and one monobactam against Chlamydia trachomatis were measured in a cell culture system. The minimal inhibitory concentration of four of the seven cephalosporins was greater than or equal to 128 micrograms/ml; those of the other three were from 16 to 32 micrograms/ml. Of the other agents, only mecillinam had activity against C. trachomatis comparable to that reported for ampicillin (minimal inhibitory concentration, less than or equal to 0.5 micrograms/ml).
  • Bacteriology of sputum in cystic fibrosis: evaluation of dithiothreitol as a mucolytic agent.

    Hammerschlag, M R; Harding, L; Macone, A; Smith, A L; Goldmann, D A (1980-06)
    Liquefaction and homogenization have been recommended to ensure accurate, representative sputum cultures. We evaluated dithiothreitol (DTT) as mucolytic agent for culturing sputum samples obtained from 79 cystic fibrosis (CF) patients. Liquefaction with DTT was not superior to direct plating of specimens for routine qualitative cultures. Unliquefied sputum cultures failed to direct 3 of 47 Pseudomonas aeruginosa isolates; DTT-treated specimens missed 5 of 13 Candida albicans isolates. Neither treated nor untreated sputum cultures were completely successful in detecting Staphylococcus aureus or Enterobacteriaceae. Since Haemophilus influenzae was recovered from only two qualitative cultures, we could not evaluate the effect of DTT on the receovery of this organism. However, 27 of 29 strains of H. influenzae were inhibited by concentrations of DTT near the recommended final working concentration of 50 micrograms/ml, suggesting that liquefaction might impair isolation of this organism. Liquefaction with DTT permitted quantitative cultures of CF sputum. The predominant pathogen in our CF population was P. aeruginosa; 37 of 43 (86%) patients were colonized with this organism. Median densities of rough and mucoid strains were 3.2 x 10(7) and 4.3 x 10(7) colony-forming units per ml, respectively. Previous oral antistaphylococcal therapy may have accounted for the observed low density of S. aureus (mean density, 3.5 x 10(3) colony-forming units per ml). We conclude that DTT treatment does not improve recovery of organisms from qualitative cultures but does facilitate quantitative studies of S. aureus and P. aeruginosa in CF sputum.
  • Growth in chick chorioallantoic membranes of strains of Newcastle disease virus of differing virulence.

    Reeve, P; Rosenblum, M; Alexander, D J (1970-03)
    The growth of eight strains of Newcastle disease virus in chick embryo chorioallantoic membranes was studied by comparing, at different times after infection, the amounts of haemagglutinin released into the allantoic fluid (extracellular haemagglutinin) with that associated with the membrane (cell-associated haemagglutinin). The virulence of the strains examined differed in that some killed chick embryos more rapidly than others. All strains released similar amounts of extracellular haemagglutinin and maximum titres were achieved about 12 hr. after infection. With virulent strains cell-associated haemagglutinin titres increased exponentially until the death of the host and maximum titres were much higher than those of extracellular haemagglutinin. With avirulent strains cell-associated haemagglutinin titres increased exponentially for only a limited time and titres were always lower than the titres of extracellular haemagglutinin.Similar results were obtained when the titres of neuraminidase and viral ribo-nucleoprotein were measured during the growth of two virulent and two avirulent strains. Virulence appears to be associated with the continued intracellular accumulation of viral antigens.
  • Bridging the Gaps: Investigating Molecular Mechanisms That Coordinate Actin Filament Assembly

    Henty-Ridilla, Jessica; Pimm, Morgan L. (2023-05)
    Cell division, migration, and maintaining cell morphology are all essential and dynamic cell processes that require precise coordination of the actin cytoskeleton. Actin monomers assemble into polar actin filaments that have a faster-growing (barbed) end and a slower-growing (minus) end. Here we examine the role of IQ-motif containing GTPase Activating Protein 1 (IQGAP1) in regulating actin filament assembly. This 189 kDa actin- binding protein slows actin filament assembly by interacting with the barbed end. Using extensive truncation analysis and single molecule microscopy techniques, we determined that IQGAP1 interacts with actin filament ends via residues within its IQ motifs. The barbed ends of actin filaments are intricately and competitively regulated by specific proteins and complexes of proteins that promote (formins) or inhibit (capping proteins) actin filament growth. We next examined the role of IQGAP1 in competitive interactions with the prominent barbed end regulators including formin and capping protein. Using fluorescently tagged proteins, IQGAP1 can be directly visualized on filament ends with individual formins and capping proteins and with formin-capping protein complexes. Interactions between IQGAP1 and formin on the ends of filaments slows formin-mediated actin assembly from 22.68 ± 2.9 subunits s-1μM-1 to 6.13 ± 0.7 subunits s-1μM-1. Further, IQGAP1 interacts with decision complexes on filament ends, creating a more complex decision complex, which decreases the dwell time on the end by 18-fold. We next examined the relevance of IQGAP1-mediated capping in cells using readouts of actin assembly: cell morphology, actin filament structure, and cell migration. Cells lacking IQGAP1 displayed significant changes to cell morphology and actin filament structures Cells expressing IQGAP1 or a capping deficient IQGAP1(CD), unable to bind filament ends, on a plasmid did not display significant changes to cell morphology or actin filament structure compared to wildtype cells. However, cells expressing IQGAP1(CD) displayed significantly slower wound closure compared to cells with endogenous IQGAP1. These results suggest that IQGAP1-mediated capping is a physiologically relevant mechanism of regulating actin filament assembly. This study reveals a role for IQGAP1 as a transient capper that promotes protein exchange on filament ends, which may have implications in the regulation of actin filament lengths in cells.
  • Primary choroidal melanoma followed by two metachronous ipsilateral ocular metastases

    Finger, P. T.; Yin, C. T.; Pavlick, A. C.; Farhat, N. (Real Time, Ltd., 2022-03-26)
    Purpose. To describe two ipsilateral, metachronous, ocular choroidal melanoma metastases. Material and methods. A 64-year-old choroidal melanoma patient was initially treated with palladium-103 ophthalmic plaque brachytherapy which induced local control of the primary cancer. Seven years later, ophthalmic findings of a second, ipsilateral, discrete choroidal melanoma prompted restaging which revealed new hepatic and nodal metastases. Systemic immunotherapy (ipilimumab 3 mg/kg with nivolumab 1 mg/kg IV every 3 weeks 4 doses) resulted in intraocular tumor regression and was followed by maintenance nivolumab 480 mg IV every 4 weeks with follow-up ophthalmic examinations. Results. Three years after initiation of systemic immunotherapy, the patient was found to have a second ipsilateral local recurrence of choroidal melanoma. It presented with retinal detachment, uveitis, and optic neuritis. Then, due to its anterior uveal location, extrascleral tumor extension was amenable to a diagnostic biopsy. Overall, 3 years after onset of metastatic uveal melanoma and 2 months after her second ocular metastasis, the patient died. This was 10 years after the initial diagnosis of choroidal melanoma. Conclusions. Metastatic choroidal melanoma can present twice in the same eye as the primary tumor. Ophthalmic and systemic examinations allowed for immunotherapy to affect initial systemic regression, vision sparing, and globe salvage.
  • Association of Perceived Social Support with Viral Suppression Among Young Adults with Perinatally-Acquired HIV in the US-based Pediatric HIV/AIDS Cohort Study (PHACS).

    Tassiopoulos, Katherine; Huo, Yanling; Kacanek, Deborah; Malee, Kathleen; Nichols, Sharon; Mellins, Claude A; Kohlhoff, Stephan; Van Dyke, Russell B (2023-05-09)
    To determine the relationship between perceived social support and viral suppression among young adults with perinatally-acquired HIV (YAPHIV).
  • Accommodation over Time in Children Wearing Multifocal Soft Contact Lenses for Myopia Control

    Zlatin, Zachary (2023-05)
    Introduction The prevalence of myopia and its ocular complications increases each year worldwide and the complications of myopia are predicted to become the leading cause of blindness by 2050 (Holden Ophthamology 2016). Common therapies for myopia management include low-dose atropine, bifocals or Progressive Addition Lenses (PALs), orthokeratology (OK), and multifocal contact lenses (MFCL). One potential mechanism for OK and MFCLs to reduce myopia progression is by imposing peripheral myopic defocus on the retina. MFCL wear can reduce accommodation compared with single vision contact lenses (SVCL), potentially reducing peripheral myopic defocus and causing variable efficacies of MFCLs (Gong OVS 2017). The change in accommodation with MFCL use varies between MFCL designs. Auditory biofeedback training can decrease the accommodative lag during MFCL wear in young adults (Wagner Sci Rep 2020). We assessed: Differences in accommodative lag between children using low-dose atropine, OK, and MFCLs compared to a single vision spectacle control. Differences in accommodation between different MFCL designs. Differences in accommodation between viewing through SVCLs and MFCLs. The effect of biofeedback training on accommodation in children during MFCL wear. Methods Myopic children habitually using low-dose atropine, OK, or MFCLs as well as myopic children not undergoing myopia management (spectacle control) (19 male/ 24 female) were recruited from the Pediatric and Myopia Management Clinics at the University Eye Center, SUNY College of Optometry. Low dose atropine (n = 11), OK (n = 5), and spectacle control (n = 11) subjects’ accommodative lag was measured using an infrared (IR) photorefractor, using a stimulus at 0, 2.5, 3, and 4D. For the MFCL subjects (n = 17), accommodation through SVCLs and their habitual MFCLs before, after, and 1 week following biofeedback training were measured identically to the other subjects at the same distances. Differences in accommodative lag were measured using mixed effects multiple linear regression adjusting for accommodative stimuli. Results There was no significant difference between accommodation in the low-dose atropine (p = 0.8), OK (p = 0.3), and MFCL (p = 0.3) groups compared to the spectacle control. Eyes wearing MFCLs exhibited significantly increased lag of accommodation compared with SVCLs prior to the biofeedback training (SV vs. MFCL, p < 0.05). Specifically, eyes viewing through Biofinity MFCLs showed a significantly greater lag than MiSight (p < 0.05). Biofeedback training showed a tendency to decrease lag immediately following biofeedback training (p = 0.2) and significantly decreased lag 1 week later (p < 0.01). Both immediately and one week later, subjects that showed lower pretreatment accommodation had significantly greater decreases in lag following biofeedback training (p < 0.05). Conclusions Our findings show that pediatric subjects wearing MFCLs for myopia management show an increased accommodative lag compared to wearing SVCLs. The lag of accommodation while viewing with MFCLs differs between MFCL designs. Biofeedback training can significantly decrease lag in children during MFCL wear one week later, similar to previous findings (Wagner Sci Rep 2020). Subjects who displayed the greatest accommodative lag prior to the train showed the biggest improvements in accommodation before the biofeedback training, suggesting individuals with low accommodation while viewing through MFCLs use may yield the greatest benefit from biofeedback training. Biofeedback training may be effective in increasing the amount of peripheral myopic defocus during MFCL wear and thus increase the efficacy of MFCL wear for myopia management in children.
  • Development of Electrohydrodynamic Printing Technology with Einzel Lens Focusing

    Strohmayer, Matthew (2021-12)
    Additive manufacturing has several advantages over conventional subtractive fabrication techniques such as CNC machining, including limited waste and the ability to build complicated structures using fewer processing steps. Recently, a cost-effective, versatile method of high-resolution printing called electrohydrodynamic printing has been developed. With this technique, droplets are deposited from a tip by applying an external electric field. This method allows for spatial resolution in the hundreds of nanometers when used in a drop-on-demand mode of operation. However, this mode has the drawback of relatively slow deposition rates. To increase the rate of deposition, it is desired to deposit the droplets using a continuous spray, which is called the cone jet mode. However, this mode of operation has a much lower resolution because of the space charge effect (lateral spread of the stream of charged droplets from Coulomb repulsion). The primary goal of this research project was to develop an electrohydrodynamic printing system with a focusing element to allow printing at much higher deposition rates than the drop-on-demand mode while maintaining reasonably high lateral resolution. After modeling different focusing systems, an Einzel lens was determined to be the optimal focusing element. A custom electrohydrodynamic printing system with a three-element Einzel lens was fabricated and tested with 10% polyethylene glycol solution. Droplets with a lateral diameter of ~1 μm after drying were successfully deposited. The incorporation of the Einzel lens resulted in an order of magnitude improvement in lateral resolution of the spray.
  • Histologically Remarkable Eosinophilic Esophagitis Responsive to Dupilumab in a Gastrostomy Tube-Dependent Pediatric Patient on Amino Acid Formula.

    Castro, Kenny; Arostegui, Dalia; Schwarz, Steven; Gandhi, Sonia; Peshimam, Juveria; Rabinowitz, Simon; Pittman, Meredith; Wallach, Thomas (2022-09-01)
    Eosinophilic esophagitis (EoE), an eosinophil predominant, TH2-mediated condition increasing in prevalence in pediatric and adult populations, is typically treated with dietary manipulations to avoid triggering antigens. However, identifying specific dietary causes remains a persistent challenge, and restrictive diets are burdensome. Total dietary modification using amino acid-based formula does not always produce symptomatic or histologic resolution, suggesting that exposure to ingested aeroallergens drives their disease. EoE patients demonstrate symptomatic exacerbation from July to September correlating with higher grass and ragweed pollen counts. We present a 7-year-old tracheostomy- and gastrostomy-dependent girl who was found on surveillance endoscopy to have profound eosinophilic infiltration throughout the esophagus with inflammatory changes including basal cell hyperplasia on histology. She responded partially to topical corticosteroid therapy with fluticasone and had complete resolution of esophageal eosinophilic infiltrate with subcutaneous dupilumab.
  • A comprehensive health effects assessment of the use of sanitizers and disinfectants during COVID-19 pandemic: a global survey.

    Hashemi, Fallah; Hoepner, Lori; Hamidinejad, Farahnaz Soleimani; Haluza, Daniela; Afrashteh, Sima; Abbasi, Alireza; Omeragić, Elma; Imamović, Belma; Rasheed, Narin A; Taher, Taqi M J; et al. (2023-05-11)
    COVID-19 has affected all aspects of human life so far. From the outset of the pandemic, preventing the spread of COVID-19 through the observance of health protocols, especially the use of sanitizers and disinfectants was given more attention. Despite the effectiveness of disinfection chemicals in controlling and preventing COVID-19, there are critical concerns about their adverse effects on human health. This study aims to assess the health effects of sanitizers and disinfectants on a global scale. A total of 91,056 participants from 154 countries participated in this cross-sectional study. Information on the use of sanitizers and disinfectants and health was collected using an electronic questionnaire, which was translated into 26 languages via web-based platforms. The findings of this study suggest that detergents, alcohol-based substances, and chlorinated compounds emerged as the most prevalent chemical agents compared to other sanitizers and disinfectants examined. Most frequently reported health issues include skin effects and respiratory effects. The Chi-square test showed a significant association between chlorinated compounds (sodium hypochlorite and per-chlorine) with all possible health effects under investigation (p-value <0.001). Examination of risk factors based on multivariate logistic regression analysis showed that alcohols and alcohols-based materials were associated with skin effects (OR, 1.98; 95%CI, 1.87-2.09), per-chlorine was associated with eye effects (OR, 1.83; 95%CI, 1.74-1.93), and highly likely with itching and throat irritation (OR, 2.00; 95%CI, 1.90-2.11). Furthermore, formaldehyde was associated with a higher prevalence of neurological effects (OR, 2.17; 95%CI, 1.92-2.44). Furthermore, formaldehyde was associated with a higher prevalence of neurological effects (OR, 2.17; 95%CI, 1.92-2.44). The use of sodium hypochlorite and per-chlorine also had a high chance of having respiratory effects. The findings of the current study suggest that health authorities need to implement more awareness programs about the side effects of using sanitizers and disinfectants during viral epidemics especially when they are used or overused.
  • Do personality characteristics predict future alcohol problems after considering current demography, substance use, and alcohol response?

    Schuckit, Marc A; Smith, Tom L; Danko, George; Bucholz, Kathleen K; Hesselbrock, Victor; Hesselbrock, Michie; Kuperman, Samuel; Kramer, John; Nurnberger, John I; Lai, Dongbing; et al. (2023-04-18)
    Several personality traits predict future alcohol problems but also relate to demographic and substance-related variables that themselves correlate with later adverse alcohol outcomes. Few prospective studies have evaluated whether personality measures predict alcohol problems after considering current demographic and substance-related variables.
  • Preoperative Depression Screening in Primary Lumbar Fusion: An Evaluation of Its Modifiability on Outcomes in Patients with Diagnosed Depressive Disorder.

    Gordon, Adam M; Elali, Faisal R; Ton, Andy; Schwartz, Jake M; Miller, Chaim; Alluri, Ram K (2023-05-11)
    Studies have reported the detrimental effects of depression following spine surgery, however none have evaluated whether preoperative depression screening, in patients with a history of depression, is protective from adverse outcomes and lowers healthcare costs. We studied whether depression screenings/psychotherapy visits within 3 months prior to 1-2 level lumbar fusion (1-2LF) were associated with lower: 1) medical complications; 2) emergency department (ED) utilizations; 3) readmissions; and 4) healthcare costs.
  • Impact of Surface Polarity on the Air Stability and Quantum Efficiency of Cs-Free III-Nitride Photocathodes

    Rocco, Emma (2023-03)
    Photocathodes are employed as photodetectors for astronomy and defense applications, as well as electron sources in high energy physics technologies. Photocathodes absorb incident photons, resulting in the emission of electrons. The III-nitride material system is promising for photocathodes due to the wide and tunable band-gap energy spanning infrared to ultraviolet wavelengths. III-nitrides are air-stable, radiation hard, and possess internal polarization charge. Nitrogen polar III-nitrides photocathodes have been predicted to achieve high device quantum efficiency (QE) and effective negative electron affinity due to alignment of the polarization and depletion charges. However, fundamental challenges of p-type doping of III-nitrides, and experimental considerations of unintentional dopant incorporation at surfaces and interfaces initially inhibited repeatable high QE N-polar photocathodes. To address these challenges, a comprehensive approach was used for the development of air-stable, high QE III-nitride photocathodes, investigating the impact of polarity on Mg-dopant incorporation efficiency, distribution of unintentional impurities due to diffusion at interfaces, and on surface passivation. The impact of hillock structures commonly present on the N-polar surface on device QE was investigated, finding a 2x increase in efficiency in photocathodes grown on high hillock density templates. Atom probe tomography (APT) measurements reveal a decrease in Mg-dopant clustering and improved incorporation efficiency in the semi-polar facets of the hillocks, leading to improved optical and electrical characteristics. Building upon this finding, a selective area growth technique is used to create hexagonal pyramid structure in both the N- and Ga-polar orientations as a model to more controllably study the mechanism of Mgincorporation within the semi-polar planes of N-polar hillocks. III-nitride hetero/homo-interfaces are commonly implemented in photocathode device design. Growth of such structures may involve growth interruption and/or exposure of the interface to ambient conditions. Incorporation and diffusion of unintentional impurities including oxygen and carbon from these interfaces has been studied here by SIMS depth profiling and modeling of defect mediated diffusion mechanisms, and their impact on photocathode performance was studied. Through consideration of interface proximity to the surface, and the temperature of processes occurring post-regrowth interface, the unintentional impurity and electrostatic profile is controlled. Emission of photoexcited electrons and hence QE depends greatly on the condition of the surface/states and its impact on surface band bending. It is well known that a non-negligible surface oxide is present on the N-polar III-nitride surface. We have observed removal of the surface oxide and deposition of positive surface charge by HCl cleaning prior to measurement, leading to an order of magnitude increase in QE. However, oxide regrowth occurs following airexposure. We have studied 2D materials including graphene and h-BN as passivation layers to prevent contamination and fully stabilize the surface charge. Sustained decrease in oxygen and carbon coverage have been measured by XPS in h-BN/GaN photocathodes after air exposure on the order of days. The combined findings of the impact of material polarity on Mg-dopant incorporation efficiency, control of the unintentional impurity profile and surface passivation was utilized to optimize the photocathode electrostatic profile for optimal device characteristics, the result of which is a maximum QE of 26.6% at 6 eV photon energy was achieved for an HCl cleaned Npolar p-GaN/u-GaN cap structure grown on high hillock density GaN template without a regrowth interface between active layers. This represents the highest reported QE for a Cs-free GaN photocathode to date [1], [2]. [1] J. Marini, I. Mahaboob, E. Rocco, L. D. Bell, and F. Shahedipour-Sandvik, “Polarization engineered N-polar Cs-free GaN photocathodes,” J. Appl. Phys., vol. 124, no. 11, p. 113101, Sep. 2018, doi: 10.1063/1.5029975. [2] E. Rocco et al., “Overview and Progress Toward High-Efficiency, Air Stable, Cs-free IIINitride Photocathode Detectors,” IEEE Photonics J., vol. 14, no. 2, p. 6818312, 2022.
  • Stability of alginate scaffolds for stromal and salivary gland epithelial cell growth

    Toro, Miriam (2022-12)
    There is a need for understanding and recreating salivary gland stromal and epithelial cell interactions to enable simulation of the process of branching morphogenesis to create gland structure and induce polarization of salivary epithelial cells to enable gland function. Previously our lab designed a method to create biocompatible “off-the-shelf” alginate hydrogel microtubes to mimic the microenvironment of salivary gland cells. Alginate hydrogels provide a useful option for a 3D scaffold due to their biocompatibility and proven use for 3D cell culture and tissue engineering. However, alginate hydrogels, in particular, those crosslinked by Ca2+ are not especially stable in the presence of phosphate, which exists in cell culture media and is required for cell growth. To address the instability of alginate hydrogels due to degradation/disassociation in the presence of phosphate, CaCl2 is needed to supplement the cell culture medium. This need leads to our current focus on addressing the following two questions: i) What is the optimal minimal concentration of CaCl2 to stabilize alginate hydrogel microtubes; and ii) What is the maximal CaCl2 concentration that allows cells to continue to grow once released from these microtubes? In this study, CaCl2 was supplemented at various concentrations between 0 mM and 50 mM (i.e., 0, 1, 2, 3.125, 6.25, 12.5, 25, and 50 mM) to determine the lowest effective concentration to stabilize alginate hydrogel microtubes while supporting cell growth and organization. The purpose of this project is to focus on the effect of CaCl2 on alginate hydrogel microtube porosity and stability, as well as its effect on cell growth and regrowth after release from alginate hydrogel microtubes. We used mouse NIH 3T3 fibroblasts as model stromal cells and salivary gland epithelial SCA-9 cells as model epithelial cells to evaluate the effects of CaCl2 concentration in monoculture and also in co-culture of these cells in alginate hydrogel microtubes. By determining the optimal CaCl2 concentration, we were able to maintain the structural integrity of our alginate hydrogel microtubes while allowing stromal and epithelial cells to grow, interact, and organize into cell clusters. This work lays a foundation for future organoid culture in alginate hydrogels for the salivary gland and beyond.

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