Ultrastructure after cryosurgery of rat liver

Ultrastructural examination of rat liver reveals significant nuclear and cytoplasmic changes at 30 min after freezing. The cytoplasmic abnormalities consist principally of changes to mitochondria and endoplasmic reticulum. Both of these changes occur prior to detectable vascular damage. Neutrophil polymorphs and thrombosis are not seen until later and are likely to be a response to rather than a cause of the injury. Adjacent cells initially show variable degrees of damage but nevertheless all cells within the lesion appear dead by 6 hr after freezing.     

Measurement of digital blood pressure after local cooling

A double-inlet plastic cuff was designed for local cooling and systolic blood pressure measurement on the middle phalanx of the fingers. With a tourniquet on the proximal phalanx of one finger, cooling for 5 min made the digital artery temperature equal the skin temperature. The difference between the systolic pressure in a control finger and in the cooled finger give the reopening pressure in the digital arteries. At 30, 25, 20, 15, and 10 degrees C, respectively the percent decrease of the finger pressure was 0.2 (0.2), 1.5 (2.5), 8.5 (3.7), 11.4 (3.4), and 15.3 (3.1) in normal young women. In patients with primary or secondary Raynaud's phenomenon, the arterial tone showed an abrupt increase that most often led to complete closure of the digital arteries. The pathological response was expressed as an increased threshold temperature or a well-defined closing temperature that showed only small variations during standardized conditions.     

Murine embryonic stem cell-derived hepatocytes correct metabolic liver disease after serial liver repopulation

Although embryonic stem (ES) cell-derived hepatocytes have the capacity for liver engraftment and repopulation, their in vivo hepatic function has not been analyzed yet. We aimed to determine the metabolic function and therapeutic action of ES cell-derived hepatocytes after serial liver repopulations in fumaryl acetoacetate hydrolase knockout (Fah(-/-)) mice. Albumin expressing (Alb(+)) cells were obtained by hepatic differentiation of ES cells using two frequently reported methods. After transplantation, variable levels of liver repopulation were found in Fah(-/-) mice recipients. FAH expressing (FAH(+)) hepatocytes were found either as single cells or as nodules with multiple hepatocytes. After serial transplantation, the proportion of the liver that was repopulated by the re-transplanted FAH(+) hepatocytes increased significantly. ES cell-derived FAH(+) hepatocytes were found in homogenous nodules and corrected the liver metabolic disorder of Fah(-/-) recipients and rescued them from death. ES cell-derived hepatocytes had normal karyotype, hepatocytic morphology and metabolic function both in vitro and in vivo. In conclusion, ES cell-derived hepatocytes were capable of liver repopulation and correction of metabolic defects after serial transplantation. Our results are an important piece of evidence to support future clinical applications of ES cell-derived hepatocytes in treating liver diseases.     

Ultrastructure of alcoholic hyalin and fate of the affected hepatocytes.

In liver biopsy specimens, foci of satellitosis, i.e., foci of alcoholic hyalin containing hepatocytes surrounded by accumulated leukocytes, were studied by means of electron-microscopic investigation. Within satellitosis hepatocytes, the same morphologic variants of alcoholic hyalin were observed as formerly described in nonsatellitosis liver cells: (1) clusters of randomly oriented smooth filaments of homogenous electron density, (2) bundles of filaments aligned in parallel arrays and exhibiting irregular densities and indistinct boundaries, and (3) masses of a strongly osmiophilic amorphous material, presumably lipidic in nature. The individual hyalin body was composed of one, two, or all three components in varying proportions; an uptake by cytosegresomes was never observed. The leukocytes of satellitosis foci, mostly polymorphonuclear ones without obvious alterations, had close contact to the central hepatocytes, and sometimes covered large holes in the hepatocellular plasma membrane. In other cases, hepatocytes and neutrophils were both destroyed and the hyalin bodies were found unaltered within the sinusoids. It is suggested that alcoholic hyalin represents an inert proteinaceous storage material, deposited at the site of synthesis which in the course of time becomes superimposed by a lipid component. In cases of alcohol-induced hepatocellular lesions, those hepatocytes which produce hyalin bodies may have a special metabolic sensitivity to alcohol which on the one hand may result in hyalin synthesis and accumulation and on the other hand may, under special conditions, lead to plasma membrane destruction with secondary satellitosis formation.     

Ultrastructure of the ring-shaped nucleoli in the hepatocytes of chick embryos]

The fine structure of ring-shaped nucleoli in hepatocytes of chick embryos at different terms of development was studied. Structural differences were shown between annular nucleoli and nucleoli with typical nucleolonemal organization. Ring-shaped nucleoli, as a rule, are devoid of nucleolonemal structure and their fibrillar component is reduced. The material which fills the central cavity always appears similar to the nucleoplasm in its structure. On the basis of serial sections, we propose that central cavity is isolated from the nucleoplasm. From the hypotonical treatment and EDTA staining application it is concluded that the central cavity of ring-shaped nucleoli contains DNP associated with the intranucleolar chromatin. The number of these nucleoli increased after the injection of a liver homogenate cytoplasmic fraction extracted from adult hen. The physiological significance of such nucleoli is discussed.     

Stimulation of proliferative and metabolic processes in the liver after administration of allogeneic hepatocytes]

The interconnection of morpho-functional changes of liver and cellular capacity to synthesize RNA and DNA in condition of the acute liver failure (ALF) and after the administration of the newborn allogenic hepatocytes (NAH) was studied by the autoradiographic method. The administration of NAH prevents, in part, the ischemic cell death and is efficient in the stimulation of the liver regeneration in ALF; it increases metabolic and proliferative activity of hepatocytes as well as of reticulo-endothelial cells.     

Ultrastructure of the "dark" hepatocytes under physiologically normal conditions and in toxic lesion of the liver (a morphometric study)]

Quanity and structural organization of the "dark" hepatocytes are different depending on the functional state of the liver. Therefore, functional estimation of the liver state with a changed number of "dark" hepatocytes demands detection of factors determining the changes in their organization and quantity in the organ.     

Ultrastructure of normal monkey liver.

The normal ultrastructure of the liver of rhesus and cynomolgus monkeys is described. A classification of type A and B periportal hepatocytes is introduced together with a discussion of the high incidence of mitochondrial abnormalities. It is suggested that the rhesus monkey is more suitable as an experimental model than the cynomolgus since its liver ultrastructure is less variable.     

Ultrastructure of liver cells of shrews]

It was established that the hepatocytes of least shrew (Sorex minutissimus) contained 1-2 nucleus with wide nuclear pores and big nucleolus. There are abundant mitochondria with numerous crists in their matrix (many organelles were divided along the crists). Each mitochondrion was surrounded by the cistern of granular endoplasmic reticulum. The ultrastructure of Golgi complex (1-2 flat cisterns, small vesicles] indicated that the bile was secreted often, by small portions, that was the adaptation to repeated fractional feeding. There were many peroxisomes in the cytoplasm of hepatocytes. Lipid droplets were absent, glycogen granules were not at all hepatocytes. Sinusoidal cells had the usual structure. All sinusoids were open and consisted of the erythrocytes, fragments of hepatocyte cytoplasm and myelin figures in its lumen.