The in vivo Orthodontic Banding Model for Vital Teeth and the in situ Orthodontic Banding Model for Hard-tissue Slabs

1992 ◽  
Vol 71 (3_suppl) ◽  
pp. 832-835 ◽  
Author(s):  
B. Øgaard ◽  
G. Rølla
Keyword(s):  
Root Surface ◽  
Model Systems ◽  
In Vivo Model ◽  
White Spot Lesions ◽  
Lesion Development ◽  
Special Diet ◽  
Mineralized Tissues ◽  
Removable Appliance

This paper presents the orthodontic banding model for vital teeth and the orthodontic in situ model for slabs of enamel, root surface, dentin, or other mineralized tissues such as shark enamel. The model for vital teeth is an in vivo model, since a crevice for plaque accumulation is created behind orthodontic bands on the buccal enamel surfaces of teeth in situ. Visible white-spot lesions are usually seen after a four-week banding period in the absence of fluoride. The microbiological flora developed behind the bands shows a similarity to that of natural caries. Microradiographic data show that the initial lesion is a softening of the enamel surface. Later, a subsurface lesion develops. A modification of the model has been developed for the use of slabs of mineralized tissues. In this model, slabs are mounted on a removable appliance. The slabs are covered with orthodontic banding material for plaque accumulation. Lesion development in enamel in the two model systems is almost identical. The benefit of the in vivo model is that caries development can be studied on vital teeth in young individuals. The model is independent of the patient's cooperation. No special diet is required, e.g., no sucrose rinsing. In the in situ model, slabs could be examined after one study period and then replaced for another period.

scholarly journals The TRH Gene Is Regulated by Thyroid Hormone at the Level of Transcription in Vivo

2010 ◽  
Vol 31 (1) ◽  
pp. 136-136
Author(s):  
Michelle L. Sugrue ◽  
Kristen R. Vella ◽  
Crystal Morales ◽  
Marisol E. Lopez ◽  
Anthony N. Hollenberg
Keyword(s):  
Thyroid Hormone ◽  
Genomic Region ◽  
Model System ◽  
Model Systems ◽  
In Vivo Model ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Normal Production

ABSTRACT The expression of the TRH gene in the paraventricular nucleus (PVH) of the hypothalamus is required for the normal production of thyroid hormone (TH) in rodents and humans. In addition, the regulation of TRH mRNA expression by TH, specifically in the PVH, ensures tight control of the set point of the hypothalamic-pituitary-thyroid axis. Although many studies have assumed that the regulation of TRH expression by TH is at the level of transcription, there is little data available to demonstrate this. We used two in vivo model systems to show this. In the first model system, we developed an in situ hybridization (ISH) assay directed against TRH heteronuclear RNA to measure TRH transcription directly in vivo. We show that in the euthyroid state, TRH transcription is present both in the PVH and anterior/lateral hypothalamus. In the hypothyroid state, transcription is activated in the PVH only and can be shut off within 5 h by TH. In the second model system, we employed transgenic mice that express the Cre recombinase under the control of the genomic region containing the TRH gene. Remarkably, TH regulates Cre expression in these mice in the PVH only. Taken together, these data affirm that TH regulates TRH at the level of transcription in the PVH only and that genomic elements surrounding the TRH gene mediate its regulation by T3. Thus, it should be possible to identify the elements within the TRH locus that mediate its regulation by T3 using in vivo approaches.

scholarly journals The Thyrotropin-Releasing Hormone Gene Is Regulated by Thyroid Hormone at the Level of Transcription in Vivo

Endocrinology ◽  
2010 ◽  
Vol 151 (2) ◽  
pp. 793-801 ◽  
Author(s):  
Michelle L. Sugrue ◽  
Kristen R. Vella ◽  
Crystal Morales ◽  
Marisol E. Lopez ◽  
Anthony N. Hollenberg
Keyword(s):  
Thyroid Hormone ◽  
Genomic Region ◽  
Model System ◽  
Model Systems ◽  
In Vivo Model ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Normal Production

The expression of the TRH gene in the paraventricular nucleus (PVH) of the hypothalamus is required for the normal production of thyroid hormone (TH) in rodents and humans. In addition, the regulation of TRH mRNA expression by TH, specifically in the PVH, ensures tight control of the set point of the hypothalamic-pituitary-thyroid axis. Although many studies have assumed that the regulation of TRH expression by TH is at the level of transcription, there is little data available to demonstrate this. We used two in vivo model systems to show this. In the first model system, we developed an in situ hybridization (ISH) assay directed against TRH heteronuclear RNA to measure TRH transcription directly in vivo. We show that in the euthyroid state, TRH transcription is present both in the PVH and anterior/lateral hypothalamus. In the hypothyroid state, transcription is activated in the PVH only and can be shut off within 5 h by TH. In the second model system, we employed transgenic mice that express the Cre recombinase under the control of the genomic region containing the TRH gene. Remarkably, TH regulates Cre expression in these mice in the PVH only. Taken together, these data affirm that TH regulates TRH at the level of transcription in the PVH only and that genomic elements surrounding the TRH gene mediate its regulation by T3. Thus, it should be possible to identify the elements within the TRH locus that mediate its regulation by T3 using in vivo approaches.

scholarly journals A novel terpenoid class for prevention and treatment of KRAS ‐driven cancers: Comprehensive analysis using in situ, in vitro, and in vivo model systems

2020 ◽  
Vol 59 (8) ◽  
pp. 886-896
Author(s):  
Arsheed A. Ganaie ◽  
Hifzur R. Siddique ◽  
Ishfaq A. Sheikh ◽  
Aijaz Parray ◽  
Lei Wang ◽  
...  
Keyword(s):  
Comprehensive Analysis ◽  
Model Systems ◽  
In Vivo Model ◽  
Prevention And Treatment

In Vitro and In Vivo Model Systems for the Study of Allergic and Inflammatory Disorders in Man

CHEST Journal ◽  
1985 ◽  
Vol 87 (5) ◽  
pp. 162S-164S ◽  
Author(s):  
Stephen P. Peters ◽  
Robert M. Naclerio ◽  
Alkis Togias ◽  
Robert P. Schleimer ◽  
Donald W. MacGlashan ◽  
...  
Keyword(s):  
Model Systems ◽  
In Vivo Model ◽  
Inflammatory Disorders

scholarly journals Diet, Obesity, and Cancer Progression: Are Adipocytes the Link?

2013 ◽  
Vol 6 ◽  
pp. LPI.S10871 ◽  
Author(s):  
Paul Toren ◽  
Benjamin C. Mora ◽  
Vasundara Venkateswaran
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Progression ◽  
Tumor Biology ◽  
Model Systems ◽  
In Vivo Model ◽  
Diet Induced Obesity ◽  
Breast And Prostate Cancer ◽  
Obesity And Cancer

Obesity has been linked to more aggressive characteristics of several cancers, including breast and prostate cancer. Adipose tissue appears to contribute to paracrine interactions in the tumor microenvironment. In particular, cancer-associated adipocytes interact reciprocally with cancer cells and influence cancer progression. Adipokines secreted from adipocytes likely form a key component of the paracrine signaling in the tumor microenvironment. In vitro coculture models allow for the assessment of specific adipokines in this interaction. Furthermore, micronutrients and macronutrients present in the diet may alter the secretion of adipokines from adipocytes. The effect of dietary fat and specific fatty acids on cancer progression in several in vivo model systems and cancer types is reviewed. The more common approaches of caloric restriction or diet-induced obesity in animal models establish that such dietary changes modulate tumor biology. This review seeks to explore available evidence regarding how diet may modulate tumor characteristics through changes in the role of adipocytes in the tumor microenvironment.

scholarly journals Unbiased in vivo preclinical evaluation of anticancer drugs identifies effective therapy for the treatment of pancreatic adenocarcinoma

2020 ◽  
Vol 117 (48) ◽  
pp. 30670-30678
Author(s):  
Olivera Grbovic-Huezo ◽  
Kenneth L. Pitter ◽  
Nicolas Lecomte ◽  
Joseph Saglimbeni ◽  
Gokce Askan ◽  
...  
Keyword(s):  
Large Scale ◽  
Single Agent ◽  
Model Systems ◽  
Ductal Adenocarcinoma ◽  
In Vivo Model ◽  
Cancer Therapies ◽  
Hsp90 Inhibition ◽  
Dismal Prognosis

Pancreatic ductal adenocarcinoma (PDAC) is typically diagnosed at an advanced stage, which limits surgical options and portends a dismal prognosis. Current oncologic PDAC therapies confer marginal benefit and, thus, a significant unmet clinical need exists for new therapeutic strategies. To identify effective PDAC therapies, we leveraged a syngeneic orthotopic PDAC transplant mouse model to perform a large-scale, in vivo screen of 16 single-agent and 41 two-drug targeted therapy combinations in mice. Among 57 drug conditions screened, combined inhibition of heat shock protein (Hsp)-90 and MEK was found to produce robust suppression of tumor growth, leading to an 80% increase in the survival of PDAC-bearing mice with no significant toxicity. Mechanistically, we observed that single-agent MEK inhibition led to compensatory activation of resistance pathways, including components of the PI3K/AKT/mTOR signaling axis, which was overcome with the addition of HSP90 inhibition. The combination of HSP90(i) + MEK(i) was also active in vitro in established human PDAC cell lines and in vivo in patient-derived organoid PDAC transplant models. These findings encourage the clinical development of HSP90(i) + MEK(i) combination therapy and highlight the power of clinically relevant in vivo model systems for identifying cancer therapies.

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