Although the measurement of hemoglobin A1c (HbA1c) using high-performance liquid chromatography (HPLC) is routinely used to estimate average blood glucose levels, it may not be accurately measured ...for various reasons, such as alteration of red blood cell lifespan and the existence of hemoglobin variants; including hemoglobin F (HbF). Here, we report cases of fulminant type 1 and type 2 diabetes mellitus in which HbA1c levels were unmeasurable because of increased labile HbA1c levels. Case 1 involved a 73-year-old man with fulminant type 1 diabetes mellitus, who was brought to our hospital with diabetic ketoacidosis. The patient’s blood glucose level was 994 mg/dL, and HbA1c was unmeasurable, which turned out to be 6.2% on the next day when the blood glucose level was normalized. Case 2 involved a 72-year-old man with type 2 diabetes mellitus, whose blood glucose level was 767 mg/dL, and HbA1c was unmeasurable, which turned out to be 17.9% the following day. In both cases, the chromatograms showed that the HbA1c peaks overlapped with large labile HbA1c peaks, which decreased the next day. It is important to keep in mind that HbA1c levels may not be accurately measured in cases of extreme hyperglycemia because of an increase in labile HbA1c, regardless of the absolute HbA1c level.
Microphthalmia‐associated transcription factor (Mitf) is a regulator for differentiation of melanoblasts that are derived from the neural crest. The mouse homozygous for the black‐eyed white ...(Mitfmi‐bw) allele is characterized by the white coat color and deafness, with black eye that is associated with the lack of melanocytes in skin and inner ear. The Mitfmi‐bw mutation is an insertion of the LINE1 retrotransposable element into intron 3 of the Mitf gene that causes the selective deficiency of the melanocyte‐specific Mitf isoform, Mitf‐M. Here, we show the expression of Mitf‐M mRNA in the trunk region of the homozygous Mitfmi‐bw (bw) mouse at embryonic days (E) 11.5 and E12.5, but Mitf‐M mRNA is undetectable at E13.5. In addition, using bw mouse that carries the lacZ transgene under the control of a melanoblast‐specific promoter, we show that the number of migrating melanoblasts in bw embryos was less than 10% of that in control embryos at E11.5 and E12.5, and melanoblasts disappear by E13.5. The loss of melanoblasts in bw embryos was probably caused by apoptosis. Finally, forced expression of Mitf‐M in the cultured neural tube of bw embryos ensured the differentiation of melanoblasts. Therefore, the correct dose of Mitf‐M is required for the normal development of melanoblasts.
Microphthalmia-associated transcription factor (Mitf) is a regulator for differentiation of melanoblasts that are derived from the neural crest. The mouse homozygous for the black-eyed white ...(Mitf(mi-bw)) allele is characterized by the white coat color and deafness, with black eye that is associated with the lack of melanocytes in skin and inner ear. The Mitf(mi-bw) mutation is an insertion of the LINE1 retrotransposable element into intron 3 of the Mitf gene that causes the selective deficiency of the melanocyte-specific Mitf isoform, Mitf-M. Here, we show the expression of Mitf-M mRNA in the trunk region of the homozygous Mitf(mi-bw)(bw) mouse at embryonic days (E) 11.5 and E12.5, but Mitf-M mRNA is undetectable at E13.5. In addition, using bw mouse that carries the lacZ transgene under the control of a melanoblast-specific promoter, we show that the number of migrating melanoblasts in bw embryos was less than 10% of that in control embryos at E11.5 and E12.5, and melanoblasts disappear by E13.5. The loss of melanoblasts in bw embryos was probably caused by apoptosis. Finally, forced expression of Mitf-M in the cultured neural tube of bw embryos ensured the differentiation of melanoblasts. Therefore, the correct dose of Mitf-M is required for the normal development of melanoblasts.
Microphthalmia‐associated transcription factor (Mitf) is a regulator for differentiation of melanoblasts that are derived from the neural crest. The mouse homozygous for the
black‐eyed white
(
Mitf
...mi‐bw
) allele is characterized by the white coat color and deafness, with black eye that is associated with the lack of melanocytes in skin and inner ear. The
Mitf
mi‐bw
mutation is an insertion of the LINE1 retrotransposable element into intron 3 of the
Mitf
gene that causes the selective deficiency of the melanocyte‐specific Mitf isoform, Mitf‐M. Here, we show the expression of Mitf‐M mRNA in the trunk region of the homozygous
Mitf
mi‐bw
(
bw
) mouse at embryonic days (E) 11.5 and E12.5, but Mitf‐M mRNA is undetectable at E13.5. In addition, using
bw
mouse that carries the
lacZ
transgene under the control of a melanoblast‐specific promoter, we show that the number of migrating melanoblasts in
bw
embryos was less than 10% of that in control embryos at E11.5 and E12.5, and melanoblasts disappear by E13.5. The loss of melanoblasts in
bw
embryos was probably caused by apoptosis. Finally, forced expression of Mitf‐M in the cultured neural tube of
bw
embryos ensured the differentiation of melanoblasts. Therefore, the correct dose of Mitf‐M is required for the normal development of melanoblasts.
Identifying both the commonalities and differences in brain structures among psychiatric disorders is important for understanding the pathophysiology. Recently, the ENIGMA-Schizophrenia DTI Working ...Group performed a large-scale meta-analysis and reported widespread white matter microstructural alterations in schizophrenia; however, no similar cross-disorder study has been carried out to date. Here, we conducted mega-analyses comparing white matter microstructural differences between healthy comparison subjects (HCS; N = 1506) and patients with schizophrenia (N = 696), bipolar disorder (N = 211), autism spectrum disorder (N = 126), or major depressive disorder (N = 398; total N = 2937 from 12 sites). In comparison with HCS, we found that schizophrenia, bipolar disorder, and autism spectrum disorder share similar white matter microstructural differences in the body of the corpus callosum; schizophrenia and bipolar disorder featured comparable changes in the limbic system, such as the fornix and cingulum. By comparison, alterations in tracts connecting neocortical areas, such as the uncinate fasciculus, were observed only in schizophrenia. No significant difference was found in major depressive disorder. In a direct comparison between schizophrenia and bipolar disorder, there were no significant differences. Significant differences between schizophrenia/bipolar disorder and major depressive disorder were found in the limbic system, which were similar to the differences in schizophrenia and bipolar disorder relative to HCS. While schizophrenia and bipolar disorder may have similar pathological characteristics, the biological characteristics of major depressive disorder may be close to those of HCS. Our findings provide insights into nosology and encourage further investigations of shared and unique pathophysiology of psychiatric disorders.
Plasma membrane compartments, delimited by transmembrane proteins anchored to the membrane skeleton (anchored-protein picket model), would provide the membrane with fundamental mosaicism because they ...would affect the movement of practically all molecules incorporated in the cell membrane. Understanding such basic compartmentalized structures of the cell membrane is critical for further studies of a variety of membrane functions. Here, using both high temporal-resolution single particle tracking and single fluorescent molecule video imaging of an unsaturated phospholipid, DOPE, we found that plasma membrane compartments generally exist in various cell types, including CHO, HEPA-OVA, PtK2, FRSK, HEK293, HeLa, T24 (ECV304), and NRK cells. The compartment size varies from 30 to 230
nm, whereas the average hop rate of DOPE crossing the boundaries between two adjacent compartments ranges between 1 and 17
ms. The probability of passing a compartment barrier when DOPE is already at the boundary is also cell-type dependent, with an overall variation by a factor of ∼7. These results strongly indicate the necessity for the paradigm shift of the concept on the plasma membrane: from the two-dimensional fluid continuum model to the compartmentalized membrane model in which its constituent molecules undergo hop diffusion over the compartments.
Single green fluorescent protein (GFP) molecules were successfully imaged for the first time in living cells. GFP linked to the cytoplasmic carboxyl terminus of E-cadherin (E-cad-GFP) was expressed ...in mouse fibroblast L cells, and observed using an objective-type total internal reflection fluorescence microscope. Based on the fluorescence intensity of individual fluorescent spots, the majority of E-cad-GFP molecules on the free cell surface were found to be oligomers of various sizes, many of them greater than dimers, suggesting that oligomerization of E-cadherin takes place before its assembly at cell-cell adhesion sites. The translational diffusion coefficient of E-cad-GFP is reduced by a factor of 10 to 40 upon oligomerization. Because such large decreases in translational mobility cannot be explained solely by increases in radius upon oligomerization, an oligomerization-induced trapping model is proposed in which, when oligomers are formed, they are trapped in place due to greatly enhanced tethering and corralling effects of the membrane skeleton on oligomers (compared with monomers). The presence of many oligomers greater than dimers on the free surface suggests that these greater oligomers are the basic building blocks for the two-dimensional cell adhesion structures (adherens junctions).
A single-molecule fluorescence resonance energy transfer (FRET) method has been developed to observe the activation of the small G protein Ras at the level of individual molecules. KB cells ...expressing H- or K-Ras fused with YFP (donor) were microinjected with the fluorescent GTP analogue BodipyTR-GTP (acceptor), and the epidermal growth factor-induced binding of BodipyTR-GTP to YFP-(H or K)-Ras was monitored by single-molecule FRET. On activation, Ras diffusion was greatly suppressed/immobilized, suggesting the formation of large, activated Ras-signaling complexes. These complexes may work as platforms for transducing the Ras signal to effector molecules, further suggesting that Ras signal transduction requires more than simple collisions with effector molecules. GAP334-GFP recruited to the membrane was also stationary, suggesting its binding to the signaling complex. The single-molecules FRET method developed here provides a powerful technique to study the signal-transduction mechanisms of various G proteins.
The interaction, binding, and colocalization of two or more molecules in living cells are essential aspects of many biological molecular processes, and single-molecule technologies for investigating ...these processes in live cells, if successfully developed, would become very powerful tools. Here, we developed simultaneous, dual-color, single fluorescent molecule colocalization imaging, to quantitatively detect the colocalization of two species of individual molecules. We first established a method for spatially correcting the two full images synchronously obtained in two different colors, and then for overlaying them with an accuracy of 13nm. By further assessing the precision of the position determination, and the signal/noise and signal/background ratios, we found that two single molecules in dual color can be colocalized to within 64–100nm (68–90% detectability) in the membrane of cells for GFP and Alexa633. The detectability of true colocalization at the molecular level and the erroneous inclusion of incidental approaches of two molecules as colocalization have to be compromised at different levels in each experiment, depending on its purpose. This technique was successfully demonstrated in living cells in culture, monitoring colocalization of single molecules of E-cadherin fused with GFP diffusing in the plasma membrane with single molecules of Alexa633 conjugated to anti-E-cadherin Fab externally added to the culture medium. This work established a benchmark for monitoring the colocalization of two single molecules, which can be applied to wide ranges of studies for molecular interactions, both at the levels of single molecules and collections of molecules.
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