Comparative evaluation on wear resistance of metal sleeve, sleeve-free resin, and reinforced sleeve-free resin implant guide: An in vitro study.

BACKGROUND: In-office three-dimensional (3D) printers and metal sleeveless surgical guides are becoming a major trend recently. However, metal sleeve-free designs are reported to be more prone to distortion which might lead to variation in the inner diameter of the drill hole and cause deviation and inaccuracy in the placement of the implant. Carbon fiber nanoparticles are reported to improve the properties of 3D printing resin material in industrial application. AIM: The purpose of the study is to evaluate and compare the wear resistance of 3D-printed implant guides with metal sleeve, sleeve-free, and reinforced sleeve-free resin to the guide drill. MATERIALS AND METHODS: A total of 66 samples with 22 samples in each group. Three groups including 3D-printed surgical guide with metal sleeve (Group A), without metal sleeve (Group B), an carbon fiber reinforced without metal sleeve (Group C) were included in the study. All samples were evaluated before sequential drilling and after sequential drilling using Vision Measuring Machine. The data were tabulated and statistically evaluated. RESULTS: The data obtained were statistically analyzed with one-way analysis of variance and posthoc test. The data obtained for wear observed in the samples showed that the wear was highest in Group B with a mean of 0.5036 ± 0.1118 and the least was observed in Group A with a mean of 0.0228 ± 0.0154 and Group C was almost similar to Group A with mean of 0.0710 ± 0.0381. The results showed there was a significant difference between Group B with Group A and C, respectively (P < 0.05). The results showed that there was no significant difference regarding the wear observed between Groups A and C (P > 0.05). CONCLUSION: The wear observed in the guide with a metal sleeve and carbon fiber reinforced without a metal sleeve was almost similar. The carbon fiber-reinforced guide showed better tolerance to guide drill equivalent to metal sleeve. Thus, carbon fiber nanoparticles reinforced in 3D printing resin have shown improved strength and can be used as a good replacement for a metal sleeve for an accurate placement of the implant.

Endogenous Fungal Endophthalmitis: A Single-Center Retrospective Study and Review of the Literature.

PURPOSE: To evaluate factors that inform systemic antifungal choices in patients with endogenous fungal endophthalmitis (EFE). DESIGN: Single-institution retrospective case series. METHODS: Charts of EFE patients from 2010 to 2023 were reviewed. Patients treated systemically for EFE with a minimum of 14 days of follow-up were included. Outcome measures included time to improvement in vitritis or chorioretinitis, systemic therapy modification, and need for surgical intervention. RESULTS: A total of 20 eyes of 16 patients were included. Candida species were most common (43.8%), followed by culture-negative EFE (37.5%) and Aspergillus species (18.8%). In all, 90% of eyes had vitritis and/or macula-involving chorioretinitis. The majority of Candida infections (60%) or culture-negative EFE (75%) were treated initially with oral antifungals. Patients with a history of immune compromise, positive fungal culture, or positive Fungitell assay were more likely to be treated with early intravenous (IV) antifungal therapy. Two patients required systemic antifungal therapy modification because of worsening chorioretinitis, in 1 case due to voriconazole-resistant Aspergillosis that demonstrated chorioretinal lesion growth despite intravitreal amphotericin B injections and systemic voriconazole, and in the second case due to worsening chorioretinitis from Candida dubliniensis infection that regressed upon switch from oral to IV fluconazole. CONCLUSIONS: Initial systemic treatment decisions in patients with EFE were driven by systemic culture positivity, systemic symptoms, or comorbidities. Intravitreal antifungal therapy may be insufficient to arrest progression of chorioretinal lesions in some cases. Larger studies are needed to determine whether visible end-organ damage in the form of chorioretinitis may be useful for guiding systemic therapy changes.

Progesterone modulates SERCA2a expression and function in rabbit cardiomyocytes.

We recently showed that progesterone treatment abolished arrhythmias and sudden cardiac death in a transgenic rabbit model of long QT syndrome type 2 (LQT2). Moreover, levels of cardiac sarco(endo)plasmic reticulum Ca(2+)-ATPase type 2a (SERCA2a) were upregulated in LQT2 heart extracts. We hypothesized that progesterone treatment upregulated SERCA2a expression, thereby reducing Ca(2+)-dependent arrhythmias in LQT2 rabbits. We therefore investigated the effect of progesterone on SERCA2a regulation in isolated cardiomyocytes. Cardiomyocytes from neonatal (3- to 5-day-old) rabbits were isolated, cultured, and treated with progesterone and other pharmacological agents. Immunoblotting was performed on total cell lysates and sarcoplasmic reticulum-enriched membrane fractions for protein abundance, and mRNA transcripts were quantified using real-time PCR. The effect of progesterone on baseline Ca(2+) transients and Ca(2+) clearance was determined using digital imaging. Progesterone treatment increased the total pool of SERCA2a protein by slowing its degradation. Using various pharmacological inhibitors of degradation pathways, we showed that progesterone-associated degradation of SERCA2a involves ubiquitination, and progesterone significantly decreases the levels of ubiquitin-tagged SERCA2a polypeptides. Our digital imaging data revealed that progesterone significantly shortened the decay and duration of Ca(2+) transients. Progesterone treatment increases protein levels and activity of SERCA2a. Progesterone stabilizes SERCA2a, in part, by decreasing the ubiquitination level of SERCA2a polypeptides.