Biomedical subjects
Publications and source records attributed to A Poletti.
The visual evoked potentials by half-field pattern reversal method were recorded in 12 hemianopic patients. The VEP amplitudes ipsilaterally to the occipital lesion were more important after periorbital acupuncture.
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In the central nervous system of the rat, the 5 alpha-reductase, the enzyme which converts testosterone into dihydrotestosterone, appears to be concentrated in the white matter and in particular to be associated with myelin. In order to verify whether a temporal correlation might exist between the formation of myelin membranes and the variations of the 5 alpha-reductase activity observed in the brain, the enzymatic activity was studied in the cerebral cortex and in the hypothalamus of male rat in the age range of 3-60 days, in myelin purified from animals of 15-60 days of life and in oligodendrocytes (i.e. in the cells responsible for the formation of the myelin) isolated from the brain of adult and very young rats (7th day of life, when the myelination process is not yet initiated). The results show that the formation of 5 alpha-androstane-17 beta-ol-3-one (DHT) in the cerebral cortex and in the hypothalamus has a peak activity in the first two weeks of life, before the beginning of the myelination process; purified myelin has an enzymatic activity always much higher than that present in the cerebral cortex and in the hypothalamus and shows a peak in the formation of DHT in the first period of myelinogenesis, on the third week of life. Finally the oligodendrocytes of young rats possess a much higher ability to convert testosterone into the 5 alpha-reduced metabolites than the oligodendrocytes of adult animals. A possible involvement of this enzyme in the myelin function may be hypothesized.
Using in situ immunohistological analysis, expression of Leu-8 and its correlation with other B-cell markers were investigated in 21 selected lymphomas of different categories, each one expressing its own typical immunophenotype. These categories included eight follicular centroblastic/centrocytic (CB/CC) lymphomas, eight intermediately differentiated lymphocytic lymphomas (ILL)/mantle zone lymphomas (MZL), and five lymphocytic lymphomas (LL) associated with chronic lymphocytic leukaemia (CLL). Four reactive lymph nodes and three tonsils were also studied using double immunolabelling procedures. Cell suspensions were also performed in three CB/CC and four ILL/MZL cases. Leu-8 was consistently expressed in ILL/MZL and LL but it was absent in most (7/8) CB/CC lymphomas. In reactive tissues, the Leu-8-positive B cells were strictly confined to the mantle zones. A close association emerged between Leu-1 (CD5) and Leu-8, both being present in ILL/MZL and LL but absent in CB/CC. A consistent lack of association was found between Leu-8 or CD5 antigens and common acute lymphoblastic leukaemia antigen (CD10) and BA-2 (CD9) antigen, whereas Leu-8 and CD5 were strictly associated with surface IgD. Reactivity with Leu-8 provides a means of distinguishing between CB/CC and ILL/MZL. Furthermore, shared immunoreactivity for Leu-8 in ILL/MZL and LL may represent a potential clue to the still uncertain cellular derivation of LL/B-CLL.
A family lineage is reported in whom several subjects, all of them females, suffered from SDAT. The existence of a subgroup of inherited dementias affecting only females is discussed.
Previous results obtained in this laboratory indicate that in the rat brain the 5 alpha-reductase, the enzymatic activity involved in metabolizing testosterone into 5 alpha-androstan-17 beta-ol-3-one (dihydrotestosterone), is particularly concentrated in the white matter. In the present experiments, this enzymatic activity was studied in the following white matter structures, which were microdissected using the punch technique of Palkovits: anterior commissure (CA), fornix (FX), habenulo-interpeduncular tract (HP), corpus callosum (CC), stria medullaris (SM), optic chiasm (CO), fimbria of the hippocampus (FI), cerebral peduncle (PC), pontine fibers (FP), cerebellar medulla (CMD) and corticospinal tract (TCS). Moreover brain myelin was isolated and purified by sucrose density gradient ultracentrifugation. The results obtained confirm that, in the rat brain, the enzymes involved in testosterone 5 alpha-reduction are preferentially localized in the white matter. However, clearcut differences in the metabolic activity exist between the different structures examined so far. DHT formation increases rostro-caudally, so that the highest activity has been recorded in the white matter structures punched at the level of pons (FP), medulla oblungata (TCS) and cerebellum (CMD). The high metabolic activity associated with the white matter structures appears to be linked to the presence of myelin, since the specific activity of the enzyme is particularly elevated in purified preparations of myelin sheaths.
Previous results have shown that human lymphocyte subpopulations are heterogeneous as to Leu-8 expression. In the present study, we performed a heretofore unreported immunohistologic analysis and flow cytometric double labeling investigation focused on Leu-8+ and Leu-8- human B cells, with special reference to their expression of other B cell lineage antigens (Leu-14, B1, OKB7 or B2, OKB2, BA-1, BA-2, IgD, and IgM) or of a functional marker of cell proliferation (Ki-67). Immunohistologic analysis was performed on frozen sections of nine normal or reactive lymph node and tonsil biopsy specimens tested with either single or paired antibodies, the latter procedure (double labeling) being directed at revealing positively subtracted Leu-8+ or Leu-8- cells expressing a given marker depending on the antibody staining sequence used. Dual flow cytometry with paired antibodies was performed on cell suspensions from four normal or reactive lymph nodes and tonsils. As to the follicular district, immunohistologic analysis suggests that germinal center (proliferating) B lymphocytes, identifiable in cell suspension as Leu-8-B1+ and representing 80% of the B1+ cells, are Leu-8- and Leu-14+, BA-2+, OKB7+, and IgM+, being rarely IgD+. Most lymphocytes located in the mantle zone (resting cells), identifiable in cell suspension as Leu-8+B1+ and representing the remaining 20% of the B1+ cells, are Leu-8+, Leu-14+. OKB7+, OKB2+, BA-1+, IgD+, and IgM+. Furthermore, from our results, there is indirect evidence to support the existence of a Leu-8+BA-2+ lymphocyte subset located in the mantle zone. Immunohistologic study of four lymph nodes by Leu-8 and Ki-67 antibody (that recognizes a nuclear, cell proliferation-associated antigen absent only in the Go phase of the cell cycle) showed that these markers are mutually exclusive and added further evidence that Leu-8 antigen is a marker of resting lymphocytes.
A comparative immunohistologic study of the cell density and distribution pattern of follicular dendritic reticulum cells (DRCs) within their follicular microenvironments (germinal centers and mantle zones) was performed by immunoperoxidase technique with a selected panel of antibodies either operationally specific for DRCs (DRC-1) or reported as having additional immunoreactivity with DRCs (antibodies to B- and T-cells, leukocytes, monocytes/macrophages, desmosomal components, and S-100 protein). Twenty-five biopsy specimens, including reactive lymph nodes and tonsils as well as normal spleen tissue, were analyzed. Serial frozen sections were tested either with single antibodies or paired monoclonal reagents in double-labeling procedures. Our results consistently indicated that DRCs positive for Leu M3 and BA-2 antibodies were confined to the central portion of germinal centers, whereas DRCs immunoreactive for S-100 protein and desmoplakin 1 and 2 were localized mostly in the central and pericentral portion of germinal centers. All the DRCs extending from the central portion of germinal centers to the mantle zones were labeled with DRC-1 and, unexpectedly, with OKB7 antibodies. Other immunostainings, such as those for HLA-DR antigens, common leukocyte antigen, and Leu 3a, were not contributory in defining topographic differences of DRCs within the follicle. The consistent heterogeneity of the labeling patterns appears to suggest a possible in situ immunophenotypic grouping of DRCs, and the concept of their possible heterogeneity appears to be corroborated.
Follicular dendritic reticulum cells (DRCs) are known to be normally present in primary follicles and both follicular centres and mantle zones of secondary follicles of peripheral lymphoid tissue. Involved frozen biopsy tissue specimens from eight cases of intermediate lymphocytic lymphoma/mantle zone lymphoma (ILL/MZL); eight cases of follicular centre cell lymphomas (FCCL) of the centroblastic/centrocytic type; and seven cases of well-differentiated lymphocytic lymphoma (WDLL) consistent with chronic lymphocytic leukaemia (CLL) were analysed immunohistologically with R4/23 (DRC-1) monoclonal antibody reactive with 'bystander' DRCs. As opposed to FCCL and most WDLL/CLL cases, the DRCs consistently formed a loose, ill-defined meshwork with a radiating or blurred outline in all MZL cases and one ILL. On the basis of the observed findings as well as from those reported in literature, the hypothesis is proposed that ILL/MZL originates from the follicular mantle zone and represents a distinct lymphoma entity owing to its peculiar immunostaining pattern of DRCs that allows it to be separated from both FCCL and WDLL/CLL. Moreover, the absence of DRCs in the microenvironment of other B-cell malignancies such as prolymphocytic leukaemia and hairy cell leukaemia, analogously with most CLL cases, would speak in favour of their different--possibly extrafollicular--compartment of origin within lymphoid tissue.
Salivary gland lymph node involvement is rare in patients at risk for AIDS. Intraparotid and perisubmaxillary gland lymph node biopsies from 2 intravenous drug abusers serologically positive for human immunodeficiency virus (HIV) affected by persistent generalized lymphadenopathy (PGL) were also analyzed immunohistologically. We found hypervascular reactive lymphoid hyperplasia with prevalence of suppressor T-cells within follicular centers often lacking surface IgD-positive mantle zone cells and showing disruption of the network of dendritic reticulum cells revealed with DRC-1 and anti-S-100 protein antibodies. Within the nodes there were numerous cysts lined by metaplastic squamous epithelium/positive for epithelial membrane antigen and containing numerous lymphocytes positive for leukocyte common antigen, macrophages positive for alpha 1 -antichymotrypsin, and Langerhans cells positive for OKT6. Salivary gland lymph nodes are immunohistologically similar to those of other sites in PGL and their increased epithelial metaplastic component containing cells involved in the immune response might represent an exuberant reaction to HIV infection.
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The phenotype of follicular dendritic reticulum cells (DRC) was analyzed with monoclonal antibodies (DRC-1, OKB7, BA-2, Leu-M3, and antidesmoplakin 1 and 2) in 28 frozen biopsy specimens of both morphologically and phenotypically analyzed B-cell lymphomas and 21 normal or reactive controls. The former included 15 follicular center cell lymphomas (FCCL), four intermediately differentiated lymphocytic lymphomas (ILL), four mantle zone lymphomas (MZL), and five well-differentiated lymphocytic lymphomas (WDLL). In controls, DRC-1+ and OKB7+ DRC were localized in both follicular centers (FC) and mantle zones (MZ), but BA-2+ and Leu-M3+ DRC were confined to FC only. FCCL were usually accompanied by DRC-1+, OKB7+, and BA-2+ DRC, and either lost or maintained positively with Leu-M3 from case to case. By contrast, MZL consistently lacked BA-2+ and Leu-M3+ DRC, and was associated with DRC-1+ and OKB7+ DRC only. Desmoplakin-positive DRC occurred in variable proportions in both FCCL and MZL. As opposed to FCCL and MZL, all WDLL and all but one of the ILL (associated only with DRC-1+, OKB7+, and desmoplakin+ DRC) did not show any DRC as identifiable with the antibody panel used. Remarkably, the difference in the distribution of BA-2+ and Leu-M3+ DRC in the normal FC and MZ appears to be maintained in their neoplastic counterparts (FCCL and MZL) also. Such a difference represents an example of the possible interactions between lymphoma cells of different phenotype and their microenvironment, as portrayed by phenotypically heterogeneous DRC.
A rapid immunohistologic method is described to analyze the possible cell origin of a given neoplasm during surgery by using selected examples of monoclonal and polyclonal antibodies (anti-cytokeratins, anti-vimentin, anti-leukocyte common antigen, and anti-keratin). This rapid (26-28 min) procedure, consisting of a two-step immunoperoxidase method, did not differ in terms of intensity and specificity of the immunoreaction from the control procedure for which conventional longer times of incubation and washing were used. The results demonstrate the feasibility and effectiveness of the procedure.
Fifty-eight paraffin-embedded lymph node biopsies from patients with Hodgkin's disease (36 nodular sclerosis, 14 mixed cellularity, five lymphocyte depletion, and three lymphocyte predominance) were immunostained with a panel of monoclonal (anti-Leu-M1, antileukocyte common antigen) and polyclonal (to lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and S-100 protein) antibodies by using the avidin-biotin immunoperoxidase technique. Both the immunostaining features of the Reed-Sternberg (R-S) cells and their variants, and the numbers of immunostained accompanying cells morphologically corresponding to macrophage-histiocytes (M-H) and to interdigitating reticulum cells (IRC) were analyzed. Variable numbers of R-S cells and their variants were positive for Leu-M1 in 83% of the cases, for alpha 1-antitrypsin in 40%, for alpha 1-antichymotrypsin in 30%, and for leukocyte common antigen in 3.4%; they were constantly negative for lysozyme and S-100 protein. Whereas the average numbers of accompanying cells immunostained for Leu-M1 were very low, the numbers of S-100-positive IRC were relatively high in all the Hodgkin's subtypes. The average numbers of M-H were lower (P less than 0.1 for lysozyme; P less than 0.001 for alpha 1-antichymotrypsin) in the nodular sclerosis than in the other pooled subtypes. In the nodular sclerosis subtype, however, R-S cells and their variants that stained positive for Leu-M1 appeared to express more frequently the lineage markers of M-H (alpha 1-antitrypsin and/or alpha 1-antichymotrypsin). These data appear to suggest that there is not an apparent qualitative correspondence between the immunostaining features of the cellular microenvironment composed of M-H and IRC and the features of the R-S cells.
Paraffin-embedded bone marrow biopsy specimens obtained prior to (37) or after (25) therapy from 62 patients with multiple myeloma (MM) were analyzed with particular reference to infiltration pattern, extent of infiltration, and myeloid to myeloma tissue percentage ratio (MMR) to verify their mutual relationships and clinicopathologic relevance. Fifty-nine biopsies were evaluable for infiltration pattern (diffuse in 27, interstitial in 25, and nodular in 7). Diffuse and interstitial patterns were more common (P less than 0.025) in stage III and stage I patients, respectively. A higher (P less than 0.001) mean serum paraprotein level was found in patients with the diffuse pattern than in those with the interstitial pattern. The average extent of infiltration by myeloma cells in the residual myeloid tissue was higher (P less than 0.001) and a high extent (75% or more) was more frequently (P less than 0.005) seen in diffuse than in interstitial pattern cases. The average MMR value was lower (P less than 0.001) and a MMR value less than 1 was more frequently (P less than 0.005) seen in the diffuse pattern group than in the interstitial pattern group. All these differences were present also when a separate analysis was performed for treated and untreated patients. It seems that a diffuse histologic pattern, as opposed to interstitial, would significantly predict a bone marrow extent of infiltration of 75% or more, a MMR lower than 1, a higher serum paraprotein level, and a clinical stage III. Bone marrow biopsy appears thus to play a role in providing parameters of prognostic relevance in MM also in the course of the disease. Prospective studies are needed to establish whether histologic pattern has an independent prognostic value.
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Involuntary groping-grasping responses to visual stimuli were studied in relation to the location of the stimuli in the space surrounding the patient. The following space-related patterns of stimulus-response were observed in four patients: (a) responses were evoked only by visual stimuli in the hemispace ipsilateral to the arm involved; (b) responses were evoked only by visual stimuli within the reach of maximal arm extension; (c) responses were evoked only by visual stimuli in the space around the hand; (d) all such patterns were variously combined. These findings are discussed in relation to the general problem of specific correlations between sensorimotor subsystems and peripersonal behavioral space.
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