Philemon Shallie

Dr. Philemon Shallie


Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
8 January 2019 in International Journal of Developmental Neuroscience
Verified
Journal Article
Closed access
PSPhilemon Shallie
Philemon Shallie
TNThajasvarie Naicker
Thajasvarie Naicker

20 July 2021 in Biomolecules
Verified
Journal Article
Open access
PDF file
XFXiujun Fan
Xiujun Fan
Muruganandan ShanmugamMuruganandan Shanmugam
Muruganandan Shanmugam
PSPhilemon Shallie
Philemon Shallie
SDSabita Dhal
Sabita Dhal
MPMatthew Petitt
Matthew Petitt
Nihar R NayakNihar R Nayak
Nihar R Nayak
Vascular endothelial growth factor (VEGF) is an angiogenic growth factor that acts primarily on endothelial cells, but numerous studies suggest that VEGF also acts on non-endothelial cells, including trophoblast cells. Inhibition of VEGF signaling by excess production of the endogenous soluble VEGF receptor sFlt1 in trophoblast cells has been implicated in several pregnancy complications. Our previous studies and other reports have shown that VEGF directly regulates placental vascular development and functions and that excess VEGF production adversely affects placental vascular development. Trophoblast giant cells (TGCs) line the maternal side of the placental vasculature in mice and function like endothelial cells. In this study, we specifically examined the effect of excess VEGF signaling on TGC development associated with defective placental vascular development using two mouse models an endometrial VEGF overexpression model and a placenta-specific sFlt1 knockdown model. Placentas of endometrial VEGF-overexpressing dams at embryonic days (E) 11.5 and 14.5 showed dramatic enlargement of the venous maternal spaces in junctional zones. The size and number of the parietal TGCs that line these venous spaces in the placenta were also significantly increased. Although junctional zone venous blood spaces from control and VEGF-overexpressing dams were not markedly different in size at E17.5, the number and size of P-TGCs were both significantly increased in the placentas from VEGF-overexpressing dams. In sFlt1 knockdown placentas, however, there was a significant increase in the size of the sinusoidal TGC-lined, alkaline phosphatase-positive maternal blood spaces in the labyrinth. These results suggest that VEGF signaling plays an important role in maintaining the homeostasis of the maternal vascular space in the mouse placenta through modulation of TGC development and differentiation, similar to the effect of VEGF on endothelial cells in other vascular beds.

18 August 2023 in Cells
Verified
Journal Article
Open access
PDF file
PAPrashanth Anamthathmakula
Prashanth Anamthathmakula
PSPhilemon Shallie
Philemon Shallie
NNNeha Nayak
Neha Nayak
SDSabita Dhal
Sabita Dhal
JVJay L. Vivian
Jay L. Vivian
Nihar R NayakNihar R Nayak
Nihar R Nayak
The aromatase-Cre recombinase (Cyp19-Cre) transgenic mouse model has been extensively used for placenta-specific gene inactivation. In a pilot study, we observed unexpected phenotypes using this mouse strain, which prompted an extensive characterization of Cyp19-Cre placental phenotypes using ROSAmT/mG transgenic reporter mice. The two strains were mated to generate bi-transgenic Cyp19-Cre;ROSAmT/mG mice following a standard transgenic breeding scheme, and placental and fetal tissues were analyzed on embryonic day 17.5. Both maternal and paternal Cre inheritance were analyzed by mating the respective Cyp19-Cre and ROSAmT/mG males and females. The genotype results showed the expected percentage of Cyp19-Cre;ROSAmT/mG fetuses (73%) and Cre mRNA was expressed in all of the Cyp19-Cre placentas. However, surprisingly, only about 50% of the Cyp19-Cre;ROSAmT/mG placentas showed Cre-mediated recombinase activity as demonstrated by placental enhanced green fluorescent protein (EGFP) expression. Further genetic excision analysis of the placentas revealed consistent results showing the absence of excision of the tdTomato in all of the Cyp19-Cre;ROSAmT/mG placentas lacking EGFP expression. Moreover, among the EGFP-expressing placentas, there was wide variability in recombination efficiency, even in placentas from the same litter, leading to a mosaic pattern of EGFP expression in different zones and cell types of the placentas. In addition, we observed a significantly higher percentage of Cre recombination activity in placentas with maternal Cre inheritance. Our results show frequent mosaicism, inconsistent recombination activity, and parent-of-origin effects in placentas from Cyp19-Cre;ROSAmT/mG mice, suggesting that tail-biopsy genotype results may not necessarily indicate the excision of floxed genes in Cyp19-Cre positive placentas. Thus, placenta-specific mutagenesis studies using the Cyp19-Cre model require extensive characterization and careful interpretation of the placental phenotypes for each floxed allele.

27 September 2021 in African Health Sciences
Verified
Journal Article
Open access
PDF file
PSPhilemon Shallie
Philemon Shallie
FHFiroza Haffejee
Firoza Haffejee
Background: The female condom (FC) is a critical component in a comprehensive and sustainable approach to prevent HIV, other sexually transmitted infections and unintended pregnancies. Objectives: This review provides comprehensive information about Nigerian’s knowledge and use of FC. Methods: We screened search output, evaluated study eligibility, and extracted data in duplicate. Data from similar studies were combined in a meta-analysis. Results: There was a significantly (p < 0.0001) high-level of awareness amongst the respondents. However, the use of the FC was very low at 5.5% among female respondents. There was a significant (p < 0.0001) difference between FC awareness and use. The main reasons for FC use were prevention of unintended pregnancy (55%) and STIs/HIV (31%). We observed a significant difference between reasons of non-use of the FC [F (5, 13) = 5.195, P = 0.0077]. Furthermore, there were significant differences between the sources of information on FC [F (3, 8) = 32.89, P < 0.0001]. Conclusion: Despite the high levels of awareness, especially among the female respondents, the use of the FC has remained extremely low even among the young, educated undergraduate students. There is aneed for robust and consistent advocacy to make the FC available and affordable. Keywords: Female condom; women; men; awareness; use; Nigeria.

1 November 2020 in Journal of Reproductive Immunology
Verified
Journal Article
Closed access
PSPhilemon Shallie
Philemon Shallie
DMDenise Margolis
Denise Margolis
OSOluwadamilola Faith Shallie
Oluwadamilola Faith Shallie
TNThajasvarie Naicker
Thajasvarie Naicker

12 December 2024 in Biomedicines
Verified
Journal Article
Open access
PDF file
PSPhilemon Shallie
Philemon Shallie
NCNathan James Carpenter
Nathan James Carpenter
PAPrashanth Anamthathmakula
Prashanth Anamthathmakula
DKDanielle Kinsey
Danielle Kinsey
MMMichael Moncure
Michael Moncure
CSCuthbert Simpkins Cuthbert Simpkins
Cuthbert Simpkins Cuthbert Simpkins
Background/Objectives: Exsanguination is a leading cause of preventable death in military and civilian settings due to extensive blood loss and hemorrhagic shock, which trigger systemic effects such as impaired tissue perfusion, hypoxia, inflammation, and multi-organ dysfunction. Standard resuscitation restores blood volume but fails to address critical aspects of hemorrhagic shock, including inflammation, coagulopathy, and reperfusion injury. To address these limitations, novel phospholipid nanoparticle (PNP)-based resuscitative fluids, VBI-S and VBI-1, were developed to modulate nitric oxide (NO) levels, improving hemodynamic stability, tissue oxygenation, and reducing inflammatory injury. This study assessed the potential of novel phospholipid nanoparticle fluids, VBI-S and VBI-1, as resuscitative agents for severe hemorrhagic shock by evaluating their ability to regulate nitric oxide, restore blood pressure, and mitigate ischemia–reperfusion injury. Methods: This study involved two phases with Sprague Dawley rats (n = 6 per group). Phase one, lasting 4 h, included four groups: blood, Ringer’s lactate, VBI-S, and VBI-1. Phase two, lasting 12 h, comprised sham, blood, and VBI-1 groups. Under anesthesia, one femoral artery was catheterized for blood pressure monitoring, and blood withdrawal from the other induced apnea. Reanimation was performed using an intra-arterial infusion of shed blood, Ringer’s lactate, VBI-S, or VBI-1. Tissue samples were analyzed histologically and for oxidative DNA damage via immunofluorescence. Chemiluminescence and rheology assessed nitric oxide interactions and viscosity. Data were analyzed using ANOVA. Results: VBI-1 and shed blood increased mean arterial pressure (MAP) from <10 mmHg to survivable levels sustained for 12 h, with VBI-1 showing significantly higher MAP at 3–4 h. Rats treated with Ringer’s lactate died within 30 min. Histology revealed reduced organ damage in VBI-1-treated rats compared to shed blood. Immunohistochemistry indicated significantly less oxidative DNA damage (p < 0.001) in VBI-1-treated rats. VBI-1 exhibited superior viscosity and nitric oxide binding. Conclusions: VBI-1 demonstrates strong potential as a resuscitative fluid, offering blood pressure restoration, reduced oxidative damage, and enhanced tissue perfusion, with significant implications for use in resource-limited and pre-hospital settings.