A survey of neurophysiological differentiation across mouse visual brain areas and timescales

Neurophysiological differentiation (ND), a measure of the number of distinct activity states that a neural population visits over a time interval, has been used as a correlate of meaningfulness or subjective perception of visual stimuli. ND has largely been studied in non-invasive human whole-brain recordings where spatial resolution is limited. However, it is likely that perception is supported by discrete neuronal populations rather than the whole brain. Therefore, here we use Neuropixels recordings from the mouse brain to characterize the ND metric across a wide range of temporal scales, within neural populations recorded at single-cell resolution in localized regions. Using the spiking activity of thousands of simultaneously recorded neurons spanning 6 visual cortical areas and the visual thalamus, we show that the ND of stimulus-evoked activity of the entire visual cortex is higher for naturalistic stimuli relative to artificial ones. This finding holds in most individual areas throughout the visual hierarchy. Moreover, for animals performing an image change detection task, ND of the entire visual cortex (though not individual areas) is higher for successful detection compared to failed trials, consistent with the assumed perception of the stimulus. Together, these results suggest that ND computed on cellular-level neural recordings is a useful tool highlighting cell populations that may be involved in subjective perception.

Characterization of Learning, Motivation, and Visual Perception in Five Transgenic Mouse Lines Expressing GCaMP in Distinct Cell Populations

To study the mechanisms of perception and cognition, neural measurements must be made during behavior. A goal of the Allen Brain Observatory is to map the activity of distinct cortical cell classes underlying visual and behavioral processing. Here we describe standardized methodology for training head-fixed mice on a visual change detection task, and we use our paradigm to characterize learning and behavior of five GCaMP6-expressing transgenic lines. We used automated training procedures to facilitate comparisons across mice. Training times varied, but most transgenic mice learned the behavioral task. Motivation levels also varied across mice. To compare mice in similar motivational states we subdivided sessions into over-, under-, and optimally motivated periods. When motivated, the pattern of perceptual decisions were highly correlated across transgenic lines, although overall performance (d-prime) was lower in one line labeling somatostatin inhibitory cells. These results provide important context for using these mice to map neural activity underlying perception and behavior.

Biological variation in the sizes, shapes and locations of visual cortical areas in the mouse

Visual cortex is organized into discrete sub-regions or areas that are arranged into a hierarchy and serves different functions in the processing of visual information. In retinotopic maps of mouse cortex, there appear to be substantial mouse-to-mouse differences in visual area location, size and shape. Here we quantify the biological variation in the size, shape and locations of 11 visual areas in the mouse, after separating biological variation and measurement noise. We find that there is biological variation in the locations and sizes of visual areas.

Growth and maturation of small hepatocytes

Proliferation of adult rat hepatocytes is observed in serum-free Dulbecco's modified Eagle's medium (DMEM) supplemented with 10 mmol/L nicotinamide and 10 ng/mL epidermal growth factor (EGF). The proliferating cells are mainly mononucleate and form small cell colonies surrounded by mature hepatocytes. Although these cells in focal colonies have a less-differentiated appearance, immunocytochemically and ultrastructurally they possess hepatic characteristics. The size of small hepatocytes is one-third to half that of mature hepatocytes. Therefore, we call the cells forming a colony, small hepatocytes. The small hepatocytes can be subcultured for several passages. Furthermore, the cells are rich in the supernatant following 50 g centrifugation for 1 min after collagenase liver perfusion. When the cells are cultured in DMEM supplemented with 10% foetal bovine serum, 10 mmol/L nicotinamide, 1 mmol/L ascorbic acid 2-phosphate, 10 ng/mL EGF and 1% dimethyl sulphoxide, each small hepatocyte can clonally proliferate for more than 3 months. A small hepatocyte divides to form a colony and the number of cells reaches more than 100 within 20 days. With time in culture, cells with a large cytoplasm appear within a colony. They have many mitochondria and large peroxisomes with crystalline nucleoids and are typical, mature hepatocytes. Immunoreactivity to connexin 32 and well-developed bile canaliculus structures are often observed in the cell-cell borders. Thus, we suggest that small hepatocytes may be considered to be 'committed progenitor cells' that can further differentiate into mature hepatocytes.

[Granulocyte colony stimulating factor (G-CSF) producing renal cell carcinoma]

A 88-year-old male patient with G-CSF producing renal cell carcinoma is reported. The patient was admitted to our hospital complaining of macrohematureia. The laboratory examination showed marked leukocytosis of 18,200/microliter (neutrophil 92%) in the peripheral blood and high levels of G-CSF (120 pg/ml) in the serum. An abdominal CT scan revealed a right renal tumor. The neutrophil count rose to 38,700/microliter with increasing of tumor size. Histopathological diagnosis was renal cell carcinoma (Grade 3) and immunohistochemical staining using Histo anti-G-CSF antibody demonstrated cancer cells produced G-CSF. This is the second case of G-CSF producing renal cell carcinoma diagnosed by immunohistochemical staining in the literature.

Different changes in expression and function of connexin 26 and connexin 32 during DNA synthesis and redifferentiation in primary rat hepatocytes using a DMSO culture system

In the present study, we determined in detail the changes of liver gap junctions, connexin 26 (Cx26), and connexin 32 (Cx32), during DNA synthesis and redifferentiation of hepatocytes in vitro. We used primary rat hepatocytes that expressed the liver gap junction proteins, which were cultured in the medium containing epidermal growth factor (EGF) with 2% dimethylsulfoxide (DMSO) and 10(-7) mol/L glucagon (a DMSO culture system), as we previously reported. In the present cultures, almost confluent hepatocytes cultured in the medium containing EGF with 2% DMSO and 10(-7) mol/L glucagon, underwent a nearly synchronous wave of DNA synthesis induced by the removal of 2% DMSO and 10(-7) mol/L glucagon, and the addition of 10 mmol/L nicotinamide, after which the DNA synthesis was completely re-inhibited by the re-addition of 2% DMSO and 10(-7) mol/L glucagon. During stimulation of DNA synthesis, both Cx26 and Cx32 messenger RNA (mRNAs) in hepatocytes transiently increased in the G1 phase and then markedly decreased before the onset of the S phase, while only Cx26 messenger RNA (mRNA) increased slightly in the S/M phase. Furthermore, before the onset of the S phase, a disappearance of both Cx26 and Cx32 immunoreactivities and gap junction plaques were observed. Gap junctional intercellular communication (GJIC), as measured by lucifer yellow, which indicated the function of Cx32, decreased markedly from before the onset of the S phase. GJIC measured by propidium iodide, which indicated the function of Cx26, decreased from before the onset of the S phase and then increased slightly in the S/M phase. During the re-inhibition after the stimulation of DNA synthesis, Cx32 mRNA, but not Cx26 mRNA, rapidly returned to the pretreatment control level. Cx32 immunoreactivity and gap junction plaques also recovered. However, the recovery of GJIC measured by lucifer yellow was later than that of Cx32 expression. These results indicated the different changes of expression and function of Cx26 and Cx32 in the hepatocytes during stimulation and re-inhibition of DNA synthesis. This culture system should be useful as a model in which to study liver gap junctions during hepatocyte growth and differentiation in vitro.

Effects of melatonin on proliferation, oxidative stress and Cx32 gap junction protein expression in primary cultures of adult rat hepatocytes

Melatonin has antiproliferative and antioxidant effects on cells in vivo and in vitro. Gap junctions mediate the communication between adjacent cells and are closely related to cellular growth and oxidative stress. We previously reported that 2% dimethylsulfoxide (DMSO) which has antiproliferative and antioxidative effects on hepatocytes, induces connexin 32 (Cx32) gap junction protein in primary cultures of adult rat hepatocytes. In the present study, we have examined the effects of melatonin on proliferation, oxidant stress and Cx32 gap junction protein expression in the cultured rat hepatocytes as compared to 2% DMSO treatment. 10(-2) M melatonin significantly inhibited the proliferation and the oxidative stress of the cells, and markedly induced Cx32 gap junction protein expression and gap junctional intercellular communication (GJIC). These effects of 10(-2) M melatonin treatment were not due to cytotoxicity to the cultured rat hepatocytes and they were as strong as those of 2% DMSO treatment. These results suggested that melatonin might be a useful substance to maintain the functions of the hepatocytes in vitro by modulating the levels of proliferation, oxidative stress and gap junction expression.

Formation of actin filament networks in cultured rat hepatocytes treated with DMSO and glucagon

Actin filament organization may play an important role in the maintenance of differentiated functions in epithelial cells. We previously reported our success in inducing and maintaining gap junctions, which are two kinds of differentiated function, in primary rat hepatocytes cultured with 2% DMSO and 10-7 M glucagon. In the present study, we demonstrated the formation of actin filament networks in the hepatocytes cultured with 2% DMSO and 10-7 M glucagon. Actin filaments in hepatocytes cultured in medium with only 2% DMSO added from 96 h after plating were concentrated under the plasma membrane and were observed to be circumferential. In hepatocytes cultured in the medium with both 2% DMSO and 10-7 M glucagon added from 96 h, not only the circumferential actin filaments but also the formation of actin filament networks were observed and the networks developed well with time in culture. The networks were observed as a dome-like structure under the cell face and terminated at the circumferential actin filaments. They were composed of electron-dense star-like vertices connected by microfilament bundles of varying length and were also very sensitive to the actin disruptor cytochalasin B. However, during the network formation, there were no significant increases in the amounts of actin protein and mRNA. The actin filament networks of the hepatocytes in this culture system might be closely related to the maintenance of differentiated functions.

[Utility of daily oral administration of etoposide in 25 cases of refractory hematological malignancies]

We estimated the utility of daily oral administration of etoposide (ETOP) in 25 cases of refractory hematological malignancies who had been admitted to our hospital between February, 1988 and October, 1995. Patients were 9 cases of malignant lymphoma, 7 cases of adult T cell leukemia (ATL), 7 cases of acute leukemia, 1 case of primary macroglobulinemia, and 1 case of chronic lymphocytic leukemia (CLL). Eight cases were elderly patients over 65 years old, 7 cases were refractory to previous chemotherapies, and 13 cases were relapsed cases. ETOP was administered at 25 or 50 mg per day for at least more than 3 consecutive weeks, if the peripheral white blood cell count exceeded 1,000/microliter. Complete and partial responses were obtained in 64% of all cases, especially in 81% of malignant lymphoma and ATL. Probability of survival for 3 years of malignant lymphoma and ATL was 36.7%. As mild toxicities, 2 cases (8%) had nausea and vomiting, 2 cases (8%) had diarrhea, and 3 cases (12%) had stomatitis. Grade 3 leukocytopenia was observed in 16% of cases. Twelve out of 16 evaluable patients recovered in performance status (PS) after this therapy. Daily oral administration of ETOP might be an effective therapy for refractory hematological malignancies, especially for malignant lymphoma.

Pulmonary veno-occlusive disease accompanied by microangiopathic hemolytic anemia 1 year after a second bone marrow transplantation for acute lymphoblastic leukemia

Although hepatic veno-occlusive disease (HVOD) is a common complication of allogenic bone marrow transplantation (BMT), pulmonary veno-occlusive disease (PVOD) is very rare. Only three cases have been described in the literature. We report the case of a 19-year-old woman who developed PVOD accompanied by microangiopathic hemolytic anemia (MAHA) and hemolytic uremic syndrome (HUS) 1 year after a second BMT for relapsed acute lymphoblastic leukemia (ALL). Autopsy examination revealed obstruction of the small pulmonary veins with edematous thickening of the intima. These findings are compatible with PVOD. Pulmonary GVHD and pulmonary aspergillosis were also observed. Various etiologic factors have been implicated in PVOD after BMT. We postulate that pulmonary GVHD and pulmonary infection including aspergillosis played an important role in the occurrence of both PVOD and HUS in our patient. Microangiopathic cytokines released in response to the GVHD and infection may damage the intima of microvessels that were previously injured by the two BMT. Despite appropriate therapy, the microangiopathic process was irreversible and the patient died. Thus, measures must be taken to prevent and treat PVOD after BMT.

Syndrome of the sea-blue histiocyte

A 39-year-old male was admitted with fever, systemic lymph node swelling, liver dysfunction and mild splenomegaly. Liver biopsy specimen showed histiocytic aggregation in portal areas. These histiocytes were closely packed with granules, dyed sea-blue with May-Giemsa staining. Further microscopical examination of lymph nodes, gastro-intestinal tract and bone marrow also revealed the accumulation of sea-blue histiocytes. Activities of lipid metabolic enzymes were normal and hematopoietic diseases which are sometimes accompanied by secondary sea-blue histiocytosis were ruled out. We diagnosed this case as syndrome of the sea-blue histiocyte.

[Investigation of reinforcement of the free enamel--the adhesive strength test and SEM observation by using the composite resin]

In this study, the purpose of which is to examine reinforcement of free enamel, we employed visible light-cured adhesive composite resins applied to the inner surface of free enamel and the enamel surface. An Autograph DCS-5000 was used to measure physical tensile shearing strength; a scanning electron microscope (SEM) was used to observe the fracture surface of the adhesive area between the enamel and the composite resin. Results 1. Adhesive strength on the inner surface of free enamel was about 20% lower than that of the enamel surface. Nonetheless, we judged the inner surface of free enamel to have adhesive strength. 2. SEM observation showed that breaking occurred at the boundary of the adhesive surface between the enamel and the bonding material. It is possible to expect a certain amount of reinforcement of free enamel from the use of composite resins.

Trapeziometacarpal abnormalities in Ehlers-Danlos syndrome

We studied 24 patients with Ehlers-Danlos syndrome with particular attention to the thumb and the trapeziometacarpal joint. The 11 males and 13 females had a mean age of 15.9 years. Symptomatic complaints included pinch, grip and twisting weakness; measurements showed dominant hand strength deficits of 71% for tip pinch, 55% for palmar pinch, 46% for key pinch, and 70% for grip. All finger joint ranges of motion were increased. Sixty-six percent of all the patients had trapeziometacarpal subluxation; 29% had dislocation. Sixteen percent had radiographic evidence of arthritis. Early occupational therapy evaluation and education can help these patients better understand and adapt to their limitations.

Comparative effects of choline chloride and phosphatidylcholine on plasma and liver lipid levels in rats fed a choline-deficient high cholesterol diet

The effects of dietary choline chloride and phosphatidylcholine (PC) on plasma and liver lipid levels were investigated with rats fed a choline-deficient high cholesterol diet. The plasma cholesterol level significantly increased as the dietary level of choline chloride was increased. The addition of PC to the choline-free diet also resulted in an increase in the plasma cholesterol level, but the magnitude of the increase was significantly lower than that by choline chloride. There was no difference, on the other hand, in the effect of choline chloride and PC on the plasma triglyceride level. The contents of cholesterol and triglyceride in the liver markedly decreased in rats fed a diet containing PC at a high level. The fecal excretion of neutral sterol significantly increased by the addition of PC at a high level, but not at a low level. The results indicate that the plasma cholesterol level, but not triglyceride, is differentially influenced by dietary choline chloride and PC, and that PC has both hyper- and antihypercholesterolemic effects when compared with a choline-free diet and a diet supplemented with choline chloride, respectively.

Coxa magna following surgical treatment of congenital hip dislocation

We studied coxa magna after operative treatment of congenital dislocation of the hip, including incidence, relationship to treatment, and influence of coxa magna on the acetabulum. Coxa magna was defined as a femoral head with a horizontal diameter at least 15% greater than the symmetrical position on the opposite side. Coxa magna developed in 16 hips (33%). The mean increase was 20.9% (range 15-30%). Three factors correlated with coxa magna: femoral osteotomy (100%), open reduction (75%), and operation at a younger age (mean 15.6 vs. 35.8 months). Four of the 16 hips developed coxa magna following Type 1 avascular necrosis; no other growth deformities appeared. At follow-up, the acetabular indices and the center edge angles were not statistically different between the coxa magna and the control groups. One must avoid confusing coxa magna with hip subluxation or inadequate reduction, of which the latter requires appropriate treatment. Coxa magna gives a good hip if a concentric, congruous reduction is obtained, providing the acetabulum has enough growth potential for remodeling.

Severe neutropenia associated with sustained-release procainamide

Neutropenia is a rare complication of procainamide therapy. However, over a period of 20 months, 8 patients developed severe neutropenia while taking a sustained-release preparation of the drug. Seven patients presented with fever and constitutional symptoms and one patient was asymptomatic. Bone marrow examinations showed myeloid aplasia or maturation arrest in 5 patients and myeloid hyperplasia in 1. Neutropenia resolved within 30 days of drug withdrawal, and all patients survived. A case-control study showed a significant association between sustained-release procainamide therapy and severe neutropenia in 5 of 114 patients (4.4%) recovering from open-heart surgery (Mantel-Haenszel chi square = 13.84; p less than 0.001). Thus, life-threatening neutropenia may be common with sustained-release procainamide preparations.