Immunological and molecular studies in a case of follicular lymphoma with an extra chromosome 12 and t(2;8) translocation.

Two sequential lymph node biopsies taken from a non-Hodgkin lymphoma patient revealed two karyotype abnormalities peculiar to B cell neoplasias: trisomy 12 and t(2;8)(p12;q24) translocation. The first was documented in all cells analyzed, while the second was present in 20% of the metaphases from the first biopsy and in 100% from the second. This suggests that the t(2;8) translocation arose as a secondary karyotypic change. In addition, although immunological characterization of the neoplastic cells disclosed a monoclonal B cell population that expressed immunoglobulin kappa light chains, as usually found in Burkitt's lymphoma with t(2;8) translocation, Southern blot analysis provided evidence of rearrangement in only one kappa chain allele.

Altered adenylate cyclase activity in human otosclerotic bone cell cultures.

Adenylate cyclase (AC) activity was studied in whole homogenates of normal and otosclerotic bone cell cultures. When Mn2+ or Ca2+ was added to the medium there was a similar increase in AC activity in both cell types. F- provoked a greater rise in normal than in pathological cells, whereas 0.01 mM guanosine triphosphate (GTP) significantly raised cAMP synthesis in otosclerotic cells only. Mn2+ + calcitonin (Ct) increased AC activity in both cell preparations. With Ca2+ as cofactor there was no significant rise in either normal or pathological cells. However, while the combination Ca2+ + Ct + GTP had little effect on normal cells, it markedly increased cAMP synthesis in the pathological cells. 1 microgram/ml of the beta-blocker propranolol inhibited the effect Ct exerts on AC in normal cells, but enhanced it in otosclerotic cells. It would, therefore, seem that the pathogenesis of otosclerosis could be associated with an alteration in the AC system associated with Ct receptors.

t(4;21) (p16;q22) in blastic crisis of a chronic myeloid leukemia with variant Philadelphia translocation.

A chronic myeloid leukemia (CML) patient who had presented a t(2;9;22) translocation during the chronic phase developed an unusual t(4;21) (p16;q22) translocation during the M2 type FAB classification blastic crisis. The role of these two recombinant chromosomes in the genesis of the terminal phase is discussed, particularly as the breakpoint on chromosome 21 near to the ets-2 oncogene locus, seems to be the same as that described in the t(8;21) (q22;q22) translocation specific of type M2 AML.

Hormonal receptor site alterations in the etiopathogenesis of otosclerosis.

The authors have studied calcium 45 uptake and cAMP intracellular levels in normal and otosclerotic bone cell cultures after stimulation with calcitonin in the presence or absence of propranolol. The results seem to demonstrate that poststimulatory 45Ca incorporation is slightly different in normal and otosclerotic cell cultures, being slower but longer lasting in the latter. Propranolol administration markedly inhibits 45Ca uptake in normal cells, while in otosclerotic cells a massive intracellular penetration becomes evident after an initial inhibitory phase. Also cAMP intracellular levels behave differently; a marked increase, followed by a rapid decrease, can be detected in normal cells after stimulation with calcitonin, while in otosclerotic cells, the increase is slower and followed by a long lasting reduction. Adding propranolol reduces cAMP levels in normal cells, while it increases levels in otosclerotic cells. The different behavior of calcium metabolism and cAMP levels after stimulation with calcitonin, depending upon the presence or absence of propranolol, seems to indicate an alteration of the transducing mechanism between stimulus, receptor, and cellular effector in otosclerotic cells.

A new case of familial paracentric inversion of chromosome 2.

A phenotypically otherwise normal homosexual man with a 46,XY,inv(2)(q21q33) karyotype inherited from his mother is described. The breakpoints were different from those observed in the only other case of familial paracentric inversion of chromosome 2 reported in the literature, but in our case they seem to correspond to constitutive and aphidicolin-induced fragile sites.

Human bone cell cultures: a new model for studying the mechanism of action of calcitonin.

An investigation on cell cultures obtained from temporal human bone fragments showed that they provide a suitable model for studying the mechanism involved in calcitonin action on bone cells. Furthermore they demonstrated: a transitory increase in 45Ca uptake that returned to control values ten minutes after the hormone was added; a relation between 45Ca uptake and increased cAMP concentrations when these were measured at the same time intervals; a reproduction of the salmon calcitonin (sCT) effect after incubation of the cultures with either db-cAMP or db-cGMP and inhibition of 45Ca uptake and parallel decrease in cAMP levels with propanol. These results suggest that in human bone cell cultures, sCT acts as a temporary promoter of 45Ca uptake, probably by activating an adenylate-cyclase system through a beta-receptor.

Morphological and functional characteristics of human temporal-bone cell cultures.

Morphology and calcium metabolism have been studied on five different cell cultures from human normal adult temporal-bone biopsies obtained during five stapedectomies. Control cell cultures were obtained from normal human skin. Four different cell types were observed in the bone biopsies: 1) osteoblast-like cells; 2) osteoclast-like cells; 3) fibroblast-like cells; 4) intermediate cells. However, morphology by itself is inadequate for clear differentiation of the four cell types. Hormonal stimulation with calcitonin and dibutyryl-cAMP in presence of 45Ca++ showed a clear-cut difference in 45Ca++ uptake between cultured cells deriving from bone and skin. Functional responses to hormonal stimulation are therefore more specific than cell shape and morphology in differentiating fibroblasts from bone cells. Since responses to hormonal stimulation confirm that temporal-bone cell cultures actually contain bone cells, such cultures seem to be a good experimental model for the study of bone morphology and physiology.

Study on normal and otosclerotic bone cell cultures: an advance in understanding the pathogenesis of otosclerosis.

The authors first reviewed the main theories concerning the pathogenesis of otosclerosis and studied the morphologic and functional characteristics of cell cultures derived from normal and otosclerotic bones. Light transmission and scanning electron microscopy did not permit definite identification of the cultured cells as predominantly osteoblasts, nor did these techniques show significant differences between cultured cells derived from normal and pathologic bone. Functional tests of the cell cultures proved more interesting. First, the bony nature of the cultured cells was demonstrated by studying the intracellular 45Ca++ uptake after stimulation with calcitonin and dybutryl-cAMP. Second, cell cultures derived from otosclerotic bone behaved differently from those derived from normal bone. Their peak uptake of calcium appeared later, and post-stimulatory values were higher, suggesting that cells derived from otosclerotic bone store a greater quantity of 45Ca++. Furthermore, after stimulation with calcitonin and propranolol, we observed an inhibition of the calcium uptake and decreased intracellular cAMP levels in normal bone cell cultures. In contrast, the cell cultures derived from otosclerotic bone exhibited an initial inhibition of calcium absorption followed by massive calcium penetration. The response of adenylate cyclase to the action of Mg++, Ca++, and F- ions was evaluated in cultures derived from normal bone, otosclerotic bone, and normal skin fibroblasts. The resulting data show that activation due to Mg++ is much lower in cultured cells derived from otosclerotic bone than in those from either normal bone or skin fibroblasts. No significant differences were found after Ca++ inhibition in any of the cell cultures. Moreover, in cell cultures derived from normal bone, F- ions induced a strong activation that was lower than the levels observed in cultures of otosclerotic bone or in normal fibroblasts. We hypothesize that an alteration at the calcitonin receptor site is responsible for the difference in calcium uptake and cAMP levels observed in the cells derived from otosclerotic bone as compared to those cultured from normal cells.

PTH induces modification of transductive events in otosclerotic bone cell cultures.

We studied the effect of PTH (10-100 nM) on transductive mechanisms (adenylate cyclase activity, Ca2+ metabolism, IP3 levels) in cell cultures derived from normal and otosclerotic human bone fragments. The cultured cells were osteoblast-like but with calcitonin-receptors still present and with PTH receptors coupled with the adenylate cyclase system. The results showed that PTH activated adenylate cyclase and increased the intracellular Ca2+ levels with qualitative and quantitative differences between the two cellular populations. In particular, otosclerotic cells responded less to hormone stimulation, which is in accord with the current hypothesis of a desensitization of the receptor/enzyme complex associated with the pathological status.

Effects of steroids on human normal and otosclerotic osteoblastic cells: influence on thymidine and leucine uptake and incorporation.

Steroid hormones are able to influence the metabolism of bone tissue in vivo, but reports regarding their direct action on bone cells fail to agree. In this study, in vitro administration of 17 beta-estradiol, testosterone and corticosterone to normal and otosclerotic osteoblastic cells induced a drop in DNA synthesis in both populations, an increase in the neosynthesis of endocellular proteins in normal cells and a rise, mainly in proteins secreted into the medium, in otosclerotic cells. The fact that 3H-thymidine and 3H-leucine uptake were lower in otosclerotic than in normal cells suggests that the membrane permeability differs in the two populations and that steroids exert an influence on both isotope uptake and directly modulate DNA and protein synthesis.

MASA syndrome: ultrasonographic evidence in a male fetus.

The recent identification of a common etiology among MASA syndrome (McKusick 303300), X-linked hydrocephalus (HSAS) (McKusick 307000) and other related neurological disorders, which had previously been considered distinct nosological entities, allowed us to diagnose MASA syndrome in a male fetus in a primigravida at the 29th week of gestation by sonographic signs of the MASA spectrum such as hydrocephalus and hypoplasia of corpus callosum. Indeed, the evidence of an X-linked neurological disease in the brother and the maternal uncle of the pregnant women enabled us to estimate a 25% risk of a male fetus being an affected hemizygote. The way in which a prenatal diagnosis, based on instrumental procedures, was reached is described since the authors were unable to perform, at the time of the observation, a molecular confirmation which was carried out only after birth.