In conventional freeze-fracture replicas produced from tissue cryoprotected with glycerol, the hydrophobic inner surfaces of membranes are revealed, but hydrophillic structures are obscured in the surrounding ice. Quick-freezing of tissue obviates the need for glycerol, which prevents the removal of this ice by etching or freeze-drying, but the major problem in freezing without glycerol cryoprotection is ice crystal formation. We describe here a simple method for quick-freezing tissue, in the absence of glycerol, on a nitrogen-cooled copper block with a hand-held specimen holder. This method freezes samples well enough to preserve molecular detail that can be revealed by subsequent etching. We show some examples of the quality of this freezing with respect to the visualization of molecular detail in isolated protein molecules such as ferritin and catalase. Furthermore, we show examples of in situ cellular structures that are revealed by this method, and we compare the structure seen in these replicas with structures preserved by quick-freezing at liquid helium temperatures.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4636126 | PMC |
| http://dx.doi.org/10.1002/jemt.1060030210 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Exploring new horizons in mid-to-far infrared nonlinear optical crystals: the significant potential of trigonal pyramidal [TeS] functional units.
Chem Sci
January 2025
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou 350002 China
Traditional tetrahedral-based mid-to-far infrared (MFIR) nonlinear optical (NLO) crystals often face limitations due to the optical anisotropy constraints imposed by their highly symmetric structures. In contrast, the relatively rare trigonal pyramidal [TeS] functional unit characterized by its asymmetric structure and stereochemically active lone pair (SCALP), offers improved optical anisotropy, hyperpolarizability and a broader IR transparency range. Despite its potential, synthetic challenges have hindered the development of MFIR NLO crystals that incorporate this unit, with only one example reported to date.
View Article and Find Full Text PDFThe Management of Iatrogenic Ureterovaginal Fistula in a Resource-Limited Setting: A 12-Year Experience at Four Fistula Surgery Centers in Uganda.
Cureus
December 2024
Obstetrics and Gynecology, Mbarara University of Science and Technology, Mbarara, UGA.
Background Ureterovaginal fistulae usually follow iatrogenic injury to the ureter during pelvic surgery. This manifests as urine incontinence and results in serious psychosocial effects on women. Ureterovaginal fistulae unlike vesicovaginal fistulae present challenges in diagnosis and management especially in resource-constrained settings.
View Article and Find Full Text PDFA bioluminescent reporter bioassay for in-process assessment of chimeric antigen receptor lentiviral vector potency.
Antib Ther
January 2025
Research and Development, Promega Corp., Madison, WI 53711, United States.
Background: Chimeric antigen receptor (CAR)-T-cell therapy is a breakthrough in the field of cancer immunotherapy, wherein T cells are genetically modified to recognize and attack cancer cells. Delivery of the CAR gene is a critical step in this therapy and is usually achieved by transducing patient T cells with a lentiviral vector (LV). Because the LV is an essential component of CAR-T manufacturing, there is a need for simple bioassays that reflect the mechanism of action (MOA) of the LV and can measure LV potency with accuracy and specificity.
View Article and Find Full Text PDFCystoscope-free ureteral stent removal: a safe and effective method during the COVID-19 pandemic.
Am J Clin Exp Urol
December 2024
Department of Urology, People's Hospital of Tibet Autonomous Region Lhasa 850000, Tibet Autonomous Region, PR China.
Ureteral stent must be removed within a certain period, usually performed under the cystoscope. However, cystoscopic operations procedures carry risks such as urethral injury, hemorrhage, and infection. This study aimed to implement a cystoscope-free method for ureteral stent removal during the COVID-19 pandemic to mitigate the complications associated with cystoscopy, reduce the risk of cross-infection, and conserve medical resources and time.
View Article and Find Full Text PDFThe Motor Melody in action Planning: The Case of Autistic Children and their Non-Autistic Siblings.
Clin Neuropsychiatry
December 2024
Consiglio Nazionale delle Ricerche, Istituto di Neuroscienze, Parma, Italy.
Objective: it is well known that during an intentional behavior, the final goal of the action shapes the entire sequence of motor acts. This chained organization has been previously demonstrated to be altered in school-age autistic children, who modulate only the final motor act according to the action goal. Here, we investigate the temporal modulation during the intentional action in three groups of preschoolers: neurotypical, autistic, and non-autistic siblings of autistic children.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!