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Biomedical subjects

L Berga

Publications and source records attributed to L Berga.

At least 19 recordsLinked to original sources
PubMed1995

[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. RESULTS: In 8 out of 20 cases (40%) a defect of band 3, alone or associated with a slight deficiency of protein 4.2, was observed. In addition to the presence of spherocytes, in all these 8 patients, a peculiar morphologic RBC alteration called pincered RBCs was also observed. Moreover, 2 cases showed a deficiency of protein 4.2, 2 cases a deficiency of ankyrin and 2 cases a deficiency of spectrin. In 6 cases (30%) the electrophoretical pattern of the erythrocyte membrane proteins was normal. A significant (r = -0.6; p < 0.01) correlation between the protein 4.2 (pallidin) and the mean corpuscular haemoglobin concentration (MCHC) was found. Also, the multiple regression analysis showed a correlation (r2 = 0.6; p < 0.0001) between the amount of protein 2.1 (ankyrin) and two hematological parameters: the mean corpuscular volume (MCV) and the red cell distribution width (RDW). CONCLUSIONS: The defect of band 3 is the most frequent membrane protein abnormality associated with HS.

Adolescent↗
PubMed1993

[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. METHODS: The adipose tissue of 25 plastic-embedded bone marrow specimens corresponding to patients with aplastic anaemia was studied stereologically. The correlation study between the results obtained and clinical and haematological data was carried out. RESULTS: The expansion of the adipose tissue is due to the predominant increase of the adipocyte number in some cases and of the adipocyte size in others. Among different clinical and haematological factors, only a lower age is significantly associated with a predominant increase of adipocyte number. In the prognostic stratification performed according to three different systems, neither the adipocyte number nor the size showed a statistically significant association. CONCLUSIONS: In the aplastic anaemia, the younger patients expand their bone marrow adipose tissue by increasing predominantly the adipocyte number, whereas in the older patients this occurs by predominantly increasing the adipocyte size (may be due to the decrease in proliferative potential). On the other hand, both the adipocyte number and size lack prognostic significance.

Adipocytes↗
PubMed1993

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). In the second part, a computer simulation model was employed for generating both control and test populations. The latter were analyzed by means of the four stereological methods and compared to the control. When applied to bone marrow specimens, no statistically significant differences were seen among the four methods. Results were very close between the Giger-Riedwyl and Saltykov methods, and between the Wicksell and Cruz-Orive methods. In the simulation model, Saltykov's method was the most accurate stereological technique for the studied conditions. Additional advantages of this method are that the assumption of Gaussian distribution is not required, and that a higher relative weight is assigned to the largest classes, in which accurate definition is easier in the microphotographs. However, since the differences among the four methods are very small, they may all be considered as valid for the stereological study of human bone marrow adipocytes.

Adipocytes↗
PubMed1993

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. Spleen weight in DAT patients (323.25 +/- 149.96 g, mean + standard deviation) was significantly increased compared with the ITP (164.28 +/- 29.79 g, P < 0.0001) and control (175.50 +/- 49.14 g, P < 0.0001) groups. The mean diameter of lymphoid follicles in the spleens of DAT patients (446.83 +/- 99.16 microns, was significantly higher than in those of the control patients (370.87 +/- 55.30 microns, P = 0.019). In control patients' spleens, the number of platelets in Billroth's cords was significantly higher (59.54 +/- 32.72/10(4) microns 2) than in those of the DAT (2.13 +/- 1.42/10(4) microns 2, P < 0.0001) and ITP (P < 0.0001) patients. The number of macrophages and ceroid histiocytes per 10(4) microns 2 of red pulp was significantly increased in both DAT (5.14 +/- 1.90) and ITP (7.48 +/- 4.38) patients compared with the control patients (3.66 +/- 1.10, P < 0.0001) and P = 0.06, respectively), and in ITP patients compared with DAT patients (P = 0.0136). The number of granulopoietic precursors per 10(4) microns 2 of red pulp was higher in the spleens of DAT (1.41 +2- 1.46, P < 0.0001) and ITP (0.92 +/- 0.75, P < 0.0001) patients compared with those of the control group. Transmission electron microscopy studies demonstrated platelet phagocytosis by macrophages of Billroth's cords and presence of myeloid metaplasia in spleens of DAT and ITP patients. Immunohistochemical studies showed a depletion of CD4+ lymphocytes in the T zone of splenic white pulp and an increased number of CD8+ lymphocytes in red pulp of DAT patients' spleens compared with those of ITP and control patients. There were no significant alterations in dendritic reticular cell network in the DAT group compared with the ITP and control groups.

Adolescent↗
PubMed1993

[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. RESULTS: The parameters FF and N/S showed a highly significant correlation (r = 0.89; p = 0.00000003) at low-normal FF range (< 40%), whereas at high FF range (> 40%), such a correlation was lacking (r = 0.01; p = 0.86). CONCLUSION: At low-normal FF the adipocyte number and size vary proportionally. Conversely, at high FF, in some cases a more marked increase of number and in other instances of adipocyte size is detected. Further investigations are needed to find out the responsible factors for this different behaviour.

Adaptation, Physiological↗
PubMed1993

[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. RESULTS: The parameters FF and N/S showed a highly significant correlation (r = 0.89; p = 0.00000003) at low-normal FF range (< 40%), whereas at high FF range (> 40%), such a correlation was lacking (r = 0.01; p = 0.86). CONCLUSION: At low-normal FF the adipocyte number and size vary proportionally. Conversely, at high FF, in some cases a more marked increase of number and in other instances of adipocyte size is detected. Further investigations are needed to find out the responsible factors for this different behaviour.

Adipose Tissue↗
PubMed1992

[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). The method of study was the stereological technique on plastic-embedded specimen sections. RESULTS: In the area II, with a fat tissue fraction markedly higher than in area I, both adipocyte number and size were significatively increased. The fat tissue fraction difference (Dif FRGR) between both areas was significatively correlated with the difference of the adipocytes number (Dif Nv) but not of the size (Dif D). However, in multiple regression both Dif Nv and Dif D contributed significatively to Dif FRGR. CONCLUSIONS: Since the histopathological pattern investigated in this work represents a model caused by intervention of local factors, it can be concluded that these can modify both the size and number of adipocytes.

Adipose Tissue↗
PubMed1992

[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. A woman is presented who had splenic haemangioma associated with leucopenia and thrombocytopenia along with decrease fibrinogen and prolonged prothrombin time as well as low complement rates. She had massive splenomegaly with portal hypertension, and the partial oxygen pressure values in mesenteric and portal blood were concurrent with the presence of arteriovenous shunts. The leucocyte and platelet count, the serum complement, the fibrinogen rate and the prothrombin time recovered after splenectomy. The cavernous characteristics of the spleen, containing multiple thrombi, were confirmed upon scanning electron microscope examination. The pathophysiology of the cytopenias and clotting factors consumption is discussed, stress being laid on the ultrastructural findings. A review is presented of the clinical aspects, differential diagnosis and treatment.

Adult↗
PubMed1990

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. The fat tissue fraction correlated positively with the size (r = .79; P less than .001) and the number/volume (r = .77; P less than .001) of adipocytes. The significance of both adipocyte size and adipocyte number/volume was confirmed by stepwise multiple regression, in which the size alone explained 62.5% of fat tissue fraction and both size and number/volume explained 95.8% of fat tissue fraction. These results are discussed from a pathophysiologic point of view.

Adipose Tissue↗
PubMed1989

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). In HS the red cell retention in the cords of Billroth was significantly increased (203 +/- 68 per 10(4) microns 2) with respect to the cases with AHA (93 +/- 35 per 10(4) microns 2) and to the controls (57 +/- 28 per 10(4) microns 2) (P = 0.004). In HS and AHA the number of macrophages per 10(4) microns 2 of red pulp was significantly increased (5.41 +/- 1.10 and 7.52 +/- 2.91, respectively) with respect to the controls (3.25 +/- 0.58) (P less than 0.003). There was no statistically significant difference between the number of macrophages in HS and AHA. The transmission (TEM) and scanning electron microscopy (SEM) studies demonstrated predominantly red cell retention in the cords of HS spleens, red cell phagocytosis by cordal macrophages in AHA spleens and in a lesser intensity in HS spleens, and phagocytosis of haematic corpuscles by sinus endothelial cells (SEC) in the cases of HS. These quantitative studies allow a better understanding of splenic red cell destruction in haemolytic syndromes.

Adolescent↗
PubMed1989

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. With increasing age, an increasing fat tissue fraction was observed (r = 0.61; p = 0.004). The fat tissue fraction correlated positively with the size (r = 0.81; p less than 0.001) and the number/volume (r = 0.59; p = 0.006) of adipocytes. The significance of both adipocyte size and adipocyte number/volume was confirmed by stepwise multiple regression, in which the size alone explained 66.2% of fat tissue fraction and both size and number/volume explained 97.2% of fat tissue fraction. These results are discussed from a pathophysiological point of view.

Adipose Tissue↗
PubMed1987

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. A stereological analysis of the Sv parameter (surface of RER per volume unit of cytoplasm) was performed in the murine myeloma line, the in vitro cultured hybridoma and the ascitic tumor hybridoma. In order to comparatively evaluate the plasmocytic differentiation of these cells the same methodology was applied to splenic lymphocytes from immunized mouse and to mature human myelomatous plasma cells. As expected, during the hybridoma process, a progressive increase in the amount of RER was detected. This was in contrast with the surface characteristics of the cells which become progressively smooth when the hybridoma was cloned, either in vitro or in vivo. From these results it can be inferred that the amount of RER is a more reliable parameter than surface blebs as a morphological element indicative of plasmocytic differentiation. On the other hand, numerous viral particles were present not only in murine myeloma line but also in hybridoma clones secreting monoclonal antibodies.

Animals↗