Self-guiding light in layered nonlinear media.

We study the propagation of intense optical beams in layered Kerr media. With appropriate shapes, beams with a power close to the self-focusing threshold are shown to propagate over long distances as quasi-stationary waveguides in cubic media supporting a periodic nonlinear refractive index.

Bone marrow changes in anorexia nervosa are correlated with the amount of weight loss and not with other clinical findings.

The clinical history and biochemical and hematologic variables for 44 consecutive patients diagnosed with anorexia nervosa were recorded. Bone marrow aspirates and biopsy specimens were analyzed by standard morphologic procedures, and bone marrow adipocytes were studied morphometrically. The bone marrow of the 44 patients was classified as normal (5 cases [11%]), hypoplastic or aplastic (17 [39%]), with partial or focal gelatinous degeneration (13 [30%]), or with complete gelatinous degeneration of the bone marrow (GDBM; 9 [20%]).

[Abnormal changes in erythrocyte membrane proteins in hereditary spherocytosis and their relation to clinical and biological aspects of the disease].

Background: In the present paper we report a study of 20 patients with hereditary spherocytosis (HS) performed with the aim of provide further information on the electrophoretic abnormalities of red blood cell (RBC) membrane proteins and their putative relationship with the clinical, biological and genetic aspects of the disease.

Methods: General hematological parameters, reticulocyte count, osmotic fragility test and erythrocyte morphology analysis, were performed by routine procedures. Membrane proteins of erythrocyte were analyzed by SDS-polyacrylamide gradient gel electrophoresis (SDS-PAGE) using the Laemmli and Fairbanks methods.

Comparative study of spleen pathology in drug abusers with thrombocytopenia related to human immunodeficiency virus infection and in patients with idiopathic thrombocytopenic purpura. A morphometric, immunohistochemical, and ultrastructural study.

A morphometric and immunohistochemical study was performed to assess the spleen's alterations in patients with autoimmune thrombocytopenia and in drug abusers with thrombocytopenia (DAT) related to human immunodeficiency virus (HIV) infection. A total of 34 patients were included in the study: 20 DAT patients and 14 with idiopathic thrombocytopenic purpura (ITP). Twenty HIV-negative splenectomy patients without thrombocytopenia were included as controls.

Stereological study of human bone marrow adipocytes. A comparison of four methods for estimating size distributions.

Several methods are available for estimating size distributions of spherical objects in tissue sections. In this article a comparative study of four stereological techniques applied to human bone marrow adipocytes was carried out. In the first part, four stereological methods (Giger-Riedwyl, Saltykov, Wicksell, and Cruz-Orive) were used for the evaluation of adipocyte size in a set of 50 human bone marrow specimens (20 normal controls, 10 aplastic, 10 hyperplastic and 10 dysplastic bone marrows).

[Acquired aplastic anemia: a stereological analysis of bone marrow fatty tissue and its clinical correlations].

Background: To analyze the changes of the number and size of bone marrow adipocytes in aplastic anaemia. To discover possible clinical and haematological factors which may be associated with predominant expansion of the number or size of adipocytes. To analyze the prognostic value of the adipocyte number and size.

[The adaptation of human bone marrow adipose tissue to various degrees of hematopoietic cellularity].

Purpose: To assess whether the variations in the number and size of the adipocytes are proportional, or not, to the changes of the fat tissue fraction (FF) associated to different degrees of hematopoietic cellularity of the bone-marrow.

Material And Methods: The material was made up of 28 specimens of bone marrow biopsy, from which 265 microscopic fields representing a wide range of FF were obtained. As index of proportionality, the ratio N/S (adipocyte number/size) was employed.

[Adaptation of human bone marrow adipose tissue to different grades of hemopoietic cellularity].

Purpose: To assess whether the variations in the number and size of the adipocytes are proportional, or not, to the changes of the fat tissue fraction (FF) associated to different degrees of hematopoietic cellularity of the bone-marrow.

Material And Methods: The material was made up of 28 specimens of bone marrow biopsy, from which 265 microscopic fields representing a wide range of FF were obtained. As index of proportionality, the ratio N/S (adipocyte number/size) was employed.

[Stereological study of the fat cells in bone marrows with a heterogeneous distribution of adipose tissue].

Purpose: 1) To analyze to what extent the fat tissue fraction of the human bone marrow with heterogeneous distribution depends on size and number of adipocytes. 2) To infer the influence of local factors on the two aforementioned parameters.

Material And Methods: The material was made up of 15 specimens of bone marrow biopsy with markedly heterogeneous distribution of fat tissue, alternating normal or hyperplastic zones (area I) with aplastic ones (area II).

[Cavernous hemangioma of the spleen with a localized intravascular coagulation syndrome (Kasabach-Merritt syndrome). Ultrastructural study].

Haemangioma is the commonest non-malignant tumour of the spleen. Cytopenia and coagulopathy, secondary to cell trapping and coagulation factors consumption inside the haemangioma, respectively. May occasionally occur as accompanying phenomena.

Variations of fat tissue fraction in abnormal human bone marrow depend both on size and number of adipocytes: a stereologic study.

Studies dealing with the number or size of individual adipose cells in abnormal human bone marrow are lacking. To ascertain whether variations in fat tissue fraction depend on the size of individual adipocytes or their number or both, a stereologic study of 30 human bone marrow specimens (10 with aplasia, 10 with hyperplasia, and 10 with dysplasia) was performed. A total of 23,435 adipocyte profiles were measured and two stereologic parameters were obtained in each specimen: mean diameter and number of cells per mm3 of bone marrow.

Morphologic and morphometric light and electron microscopic studies of the spleen in patients with hereditary spherocytosis and autoimmune haemolytic anaemia.

With the aim of contributing to a better understanding of the haemolytic function of the spleen, a morphologic and morphometric study of this organ fixed by arterial perfusion was performed in nine patients with hereditary spherocytosis (HS), three with autoimmune haemolytic anaemia (AHA) and six with Hodgkin's disease without splenic involvement (controls). The spleen weight in HS and AHA (621 +/- 429 g, mean +/- SD) was significantly increased with respect to controls (168 +/- 36 g) (P = 0.003).

Age-related variations of fat tissue fraction in normal human bone marrow depend both on size and number of adipocytes: a stereological study.

Studies dealing with the number or size of individual adipose cells in human bone marrow are lacking. To ascertain whether the age-related variations in fat tissue fraction depend on the size of individual adipocytes or their number or both, a stereological study of 20 normal human bone marrow specimens was performed. A total number of 17,039 adipose cell profiles was measured and two stereological parameters were obtained in each specimen: mean diameter and number of cells per mm3 of bone marrow.

Hybridoma process: ultrastructural cytology of different stages.

In order to define the ultrastructure of the hybridoma cell and to learn more about the plasmocytic differentiation process, a scanning (SEM) and transmission (TEM) electron microscopy study of several cell types involved in the production of monoclonal antibodies was performed. Cells of the three different stages in hybridoma process were studied. These cells included NS/1 murine myeloma cells, 40-3A4 in vitro cultured hybridoma and 33-1D2 ascitic tumor hybridoma cells.

Viscometric methods for assessing red cell deformability and fragmentation.

Erythrocyte deformability is an important determinant of red cell life span and depends on at least three key factors: shape, internal viscosity and membrane mechanical properties. In this paper we describe three viscometric methods for assessing red cell deformability and fragmentation: 1) Plasma and whole blood are sheared with a coneplate viscometer at high shear rates. A mathematical model for liquid behaviour is applied to the results from plasma and whole blood viscosity, and a rheological parameter called internal viscosity is obtained.