[Representations of object animacy and real-world size in the ventral visual pathway]

How the brain perceives objects and classifies perceived objects is one of the important goals of visual cognitive neuroscience. Previous research has shown that when we see objects, the brain's ventral visual pathway recognizes and classifies them, leading to different ways of interacting with them. In this paper, we summarize the latest research progress of the ventral visual pathway related to the visual classification of objects. From the perspective of the neural representation of objects and its underlying mechanisms in the visual cortex, we summarize the current research status of the two important organizational dimensions of object animacy and real-world size, provide new insights, and point out the direction of further research.

Rhesus monkey neural stem cell transplantation promotes neural regeneration in rats with hippocampal lesions

Rhesus monkey neural stem cells are capable of differentiating into neurons and glial cells. Therefore, neural stem cell transplantation can be used to promote functional recovery of the nervous system. Rhesus monkey neural stem cells (1 × 10⁵ cells/μL) were injected into bilateral hippocampi of rats with hippocampal lesions. Confocal laser scanning microscopy demonstrated that green fluorescent protein-labeled transplanted cells survived and grew well. Transplanted cells were detected at the lesion site, but also in the nerve fiber-rich region of the cerebral cortex and corpus callosum. Some transplanted cells differentiated into neurons and glial cells clustering along the ventricular wall, and integrated into the recipient brain. Behavioral tests revealed that spatial learning and memory ability improved, indicating that rhesus monkey neural stem cells noticeably improve spatial learning and memory abilities in rats with hippocampal lesions.

Changes in hippocampal ultrastructure and vimentin expression in rhesus monkeys following selective deep hypothermia and blood occlusion

Previous studies have shown that selective cerebral profound hypothermia combined with antegrade cerebral perfusion can improve resistance to cerebral hypoxia-ischemia in monkeys. The aim of this study was to observe the effect of selective cerebral profound hypothermia on the ultrastructure and vimentin expression in monkey hippocampi after severe cerebral ischemia. Eight healthy adult rhesus monkeys were randomly divided into two groups: profound hypothermia (N = 5) and normothermia (N = 3). Monkeys in the profound hypothermia group underwent bilateral carotid artery and jugular vein occlusion for 10 minutes at room temperature. Ringer's solution at 4°C was then perfused through the right internal carotid artery and out of the right jugular vein, maintaining the brain temperature below 18°C. Sixty minutes later, cerebral blood flow was restored. The normothermia group underwent all procedures with the exception that the Ringer's solution was 37°C during perfusion. All animals in the profound hypothermia group were successfully resuscitated. No significant abnormalities of hippocampal morphology or ultrastructure were observed. In contrast, no monkeys were alive after perfusion in the normothermia group and they had abnormal hippocampal morphology and ultrastructure to different extents. Vimentin expression in the hippocampus was significantly lower in the profound hypothermia group (47.88% ± 1.66) than the normothermia group (79.51% ± 1.00; P < 0.01). We conclude that selective cerebral profound hypothermia following 10-min occlusion of the bilateral common carotid arteries was able to downregulate vimentin expression in the hippocampus and protect it from severe cerebral ischemia.

Prokaryotic expression and immunoassay of grass carp reovirus capsid VP6 protein

Grass carp reovirus (GCRV) of the genus Aquareovirus and the family Reoviridae causes a severe hemorrhagic disease in grass carp fingerlings in China. GCRV genome is composed of 11 double-stranded RNA segments, of which segment 8 encodes the major core capsid protein VP6. In this study, the VP6 gene following an RT-PCR-amplification from the GCRV 104 strain was cloned into an expression vector pET-32a to obtain pET-32(a)-VP6. The VP6 protein was expressed in Escherichia coli BL21 as a fusion protein of 64 kDa. After purification with the HisLink Spin Protein Purification System the VP6 protein was used to raise a specific polyclonal antibody in Balb/c mice. Presence of VP6 protein was proved in bacterial lysates containing VP6 fusion protein by Western blot analysis and in GCRV-infected CIK cells by immunofluorescent staining using polyclonal antibody. These results may be helpful in further studies of interactions between GCRV and cells and in preparation of an engineered vaccine against GCRV.

[A technique of rhesus monkey neural progenitor cells intravitreal transplant to rats]

To investigate a simple and effective intraocular xenotransplant technique of rhesus monkey neural progenitor cells to rats, mechanical injury was induced in the rat's right retina. And the GFP-labeled rhesus monkey neural progenitor cells suspension was slowly injected into the vitreous space of the right injured and left control eye. Confocal image suggested that the xenografted cells survived in both the injured and control eye, meanwhile the cells integrated in the injured right retina. The results demonstrated that intravitreal xenotransplant could be adopted as a simple and reliable method.

T1 relaxation times for viability evaluation of the engrafted and the native liver in a rat model of heterotopic auxiliary liver transplantation: a pilot study

Following a heterotopic auxiliary liver transplantation, commonly used measurements are either invasive or non-indicative of individual viability of the coexisting engrafted and native livers. Magnetic resonance imaging (MRI) was therefore tested for its potential to monitor the post-transplant hepatic viability in a rat model. Thirteen Wistar rats were systematically evaluated with MRI and serum biochemical liver parameters. Post-transplant complications and the causes of animal death were identified by autopsy and histo-pathological examinations. The data of the healthy survivors were compared with those of the rats that developed complications. On MRI, the hepatic complications could be depicted in the individual livers. A specific pattern of signal evolution was found in the livers of the healthy survivors: the mean T1 relaxation times of the engrafted livers increased immediately after transplantation (476 +/- 64 ms, mean +/- standard deviation, pre-operative; 730 +/- 48 ms, week 1) and then declined steadily to a 3 month value of 489 +/- 246 ms, while, following a transient first rise (476 +/- 64 ms, pre-operative; 589 +/- 28 ms, week 1), the mean T1 value of the native livers increased again 4 weeks after surgery and reached a 3 month value of 859 +/- 43 ms. However, in the rats with various complications, the mean T1 relaxation times of the engrafted livers continued to increase throughout the first post-operative month (760 +/- 48 ms, week 1; 922 +/- 76 ms, week 4), while that of the native liver only varied mildly (546 +/- 25 ms, week 1; 473 +/- 25 ms, week 4). After the first post-transplant week, the healthy engrafted livers could already be distinguished from those with complications by a significant decrease in T1 relaxation times. These data suggest that, besides demonstrating major complications, MRI may allow one to monitor the viability of each liver by analysing the relative signal intensity and T1 relaxation times after a heterotopic auxiliary liver transplantation.

Effects of Re-arterialization on early graft function and regeneration in the rat model of heterotopic auxiliary liver transplantation

In the rat model of heterotopic auxiliary liver transplantation, graft re-arterialization may influence the outcome of inter-liver competition. This was investigated in the current study using two transplanted groups with or without graft re-arterialization. Immediately after reperfusion, the re-arterialized grafts showed significantly higher bile flow rate and bilirubin excretion than the grafts without re-arterialization. DNA synthesis rate was also increased more drastically in the re-arterialized group following the transplantation. Without re-arterialization, the rats developed more pronounced cytolysis and cholestasis. Among the long-term survivors, all healthy re-arterialized grafts regenerated, whereas 5/6 non-re-arterialized grafts atrophied. These data demonstrate that the re-arterialization increases graft survival by improving early hepatic function, enhancing regenerative response and preventing post-transplant biliary complications in this rat model.

Evaluation of graft viability in heterotopic auxiliary liver transplantation in the rat

In the rat model of heterotopic auxiliary liver transplantation, the coexistence of the engrafted liver and the recipient's native liver makes it difficult to evaluate the posttransplant graft viability. In this study, auxiliary liver transplantation was performed in Wistar rats, in which the recipient's native liver was handicapped with a 68% partial hepatectomy and a common bile duct ligation. Serum biochemistry of the liver was analyzed and compared with that of the selected control group. The surgical handicap of the liver showed severe damaging effects: the handicapped native livers appeared atrophic at autopsy, and no long-term animal survival could be achieved without an auxiliary liver transplantation. As the engrafted liver corrected the cholestasis of the handicapped native liver, significant differences of serum biochemistry were found between the transplanted group and the control group: for bilirubin concentration and gamma glutamyl transferase activity from postoperative day 3 to 28 (p < .05); for alkaline phosphatase on days 3, 7, 14, and 28 (p < .05); for alanine aminotransferase activity on days 3 and 14 (p < .05); and for aspartate aminotransferase activity on day 14 (p < .05). The efficiency to induce hepatic failure and to hamper its regeneration capacity in the native liver makes animal survival and liver biology as reliable parameters to evaluate the posttransplant graft viability in this rat model.

The need to handicap the recipient's native liver in the rat model of heterotopic auxiliary liver transplantation

In the rat model of heterotopic auxiliary liver transplantation (HALTx), the opinion varies on whether and how the recipient's native liver should be handicapped. To avoid atrophy of the transplanted organ, in this study, two different handicaps were evaluated and their effects on post-operative animal survival and liver biology are described. With a sole portacaval shunt (group 1) all rats survived longer than 3 months. An additional handicap of the liver with either a 68% partial hepatectomy (68% PH) (group 2), or both a 68% PH and a common bile duct ligation (CBDL) (group 3) led to a 100% mortality within 2 days after surgery. When an auxiliary liver was transplanted to the rats handicapped with a 68% PH (group 4), serum Bilirubin and ALAT values were significantly lower than those handicapped with both a 68% PH and a CBDL (group 5). Autopsy and histology of the long-term survivors revealed the atrophy of the engrafted livers and the regeneration of the native livers in group 4, whereas it showed the opposite in group 5. Thus the various manipulations of the native liver do influence differently the post-transplant animal survival, serum liver biochemistry and the outcome of the engrafted liver in this rat model of HALTx.

Listeriosis as an obstetric complication in an immunocompromised patient

We have reported a case of maternal death associated with Listeria monocytogenes septicemia in a woman who was being treated with immunosuppressive drugs for lupus nephritis. This report, coupled with a previous case of L monocytogenes sepsis in a pregnant patient with AIDS, emphasizes that L monocytogenes infection may be an important, unrecognized pathogen in pregnant women with impaired immunity.

Acute pyelonephritis in pregnancy

There were 107 episodes of pyelonephritis associated with pregnancy or the early puerperium occurring in 103 gravidas investigated retrospectively for information concerning prematurity, low birthweight, and antibiotic susceptibility patterns in the recovered microorganisms. No difference was found in the incidence of prematurity on low birthweight between that group and a control group of gravidas from the same population. Members of the Enterobacteriaceae genus were the most common bacterial isolates from the urine, with a large portion of E. coli being resistant to both ampicillin (33%) and cephalothin (13%). Treated pyelonephritis associated with pregnancy does not appear to predispose to prematurity or low birthweight in this population. Also, initial therapy with a first-generation cephalosporin may no longer be appropriate, because a significant number of isolates (11%) were resistant to cephalothin.

Elevated mannose levels detected by gas-liquid chromatography in hydrolysates of serum from rats and humans with candidiasis

We have developed a gas-liquid chromatographic method for identification of mannose in serum hydrolysates by utilizing peracetylated aldononitrile derivatives. Experimentally infected rats and human subjects with candidiasis were studied. Peaks in unknown samples were identified by co-chromatography of reference carbohydrates. Inositol was used as an internal standard. Mannose was identified in hydrolysates of normal rat (391.85 +/- 66.18 micrograms/ml) and human (297.87 +/- 77.81 micrograms/ml) sera. Significantly increased concentrations of mannose (greater than 526.21 micrograms/ml) were demonstrated in hydrolysates of sera from 26 of 36 (72%) experimentally infected rats tested 1 or more days after onset of infection. Significant increases (greater than 453.49 micrograms/ml) were also seen in humans with localized (6/15), transient (2/2), and disseminated (5/7) candidiasis. The concentrations were highest in patients with candidemia occurring either transiently or as part of disseminated infection. The concentrations in patients with localized candidiasis were lower but were still significantly greater than control. These data suggest that changes in mannose concentration, as measured, may serve as markers of candidiasis. The amount of mannose present may be in part a function of the extent of the infection.