Antisickling effects of 2,3-diphosphoglycerate depletion

Elevation of 2,3-bisphosphoglycerate (2,3-DPG) in sickle erthrocytes (SS RBCs) and concomitant acidification of the cell interior promote polymerization by decreasing the solubility (csat) of deoxyhemoglobin S. The antisickling effect of 2,3-DPG depletion was evaluated after activation of the 2,3-DPG phosphatase activity of bisphosphoglycerate mutase by glycolate-2-phosphate, leading to rapid loss of intracellular 2,3-DPG. To ensure its maximal reduction in a physiologic medium, isosmotic CO2/bicarbonate-buffered saline, pH 7.0, was used. Substitution of K+ for Na+ as the major extracellular cation suppressed K:Cl cotransport, prevented cell shrinkage, and allowed demonstration of the full antisickling effect of 2,3-DPG depletion. The modest effect on solubility per se of removing intraerythrocytic 2,3-DPG (delta Csat = 1.6 g/dL) was amplified into a much larger antisickling effect by interaction with three other cellular variables affecting solubility and polymer content (intracellular pH, O2 saturation, and mean cell hemoglobin concentration). Acting in concert, these four antisickling effects (three solubilizing, one osmotic) reduced polymer fraction of glycolate-treated SS RBCs by 32% to 63%, with a concomitant decrease in sickling of 46% to 95% at the nominal pO2 of the microcirculation (20 mm Hg). A decrement in sickling of this magnitude should significantly ameliorate the vasoocclusive severity of sickle cell disease.     

Induction of apoptotic cell death in chronic lymphocytic leukemia by 2- chloro-2'-deoxyadenosine and 9-beta-D-arabinosyl-2-fluoroadenine

2-Chloro-2'-deoxyadenosine (CldAdo) and 9-beta-D-arabinosyl-2- fluoroadenine (F-ara-A) have shown marked activity in the treatment of indolent lymphoid malignancies. Based on the susceptibility of various lymphocyte populations to apoptosis, we investigated whether CldAdo or F-ara-A would induce this process in lymphocytes from patients with chronic lymphocytic leukemia (CLL). In vitro exposure of leukemic lymphocytes to CldAdo or F-ara-A for 24 to 72 hours elicited features of apoptosis visible by light and electron microscopy. Analysis of DNA integrity showed DNA cleavage into nucleosomal-sized multimers. Using a quantitative assay, drug-induced DNA fragmentation was both time and dose dependent. Inhibition of active macromolecular synthesis did not prevent drug-induced fragmentation; however, both drug-induced and spontaneous DNA fragmentation were prevented by intracellular calcium chelation. In vitro culture with phorbol ester generally decreased drug- induced DNA cleavage. After prolonged incubation, CLL cells exhibited spontaneous cleavage; albeit, at significantly lower rates than drug- treated cells. Heterogeneity was observed for spontaneous and drug- induced DNA fragmentation and was significantly lower in B-leukemic cells obtained from patients with high-risk and refractory disease. We conclude that CldAdo and F-ara-A are potent inducers of apoptotic death in CLL and that this feature correlates with the disease status.     

神经肽DGAVP和Org2766对神经细胞内游离Ca2+的影响

运用Ca²⁺指示剂Fura-2作为细胞内钙离子的荧光探针,利用AR—CM—MIC阳离子测定系统,检测了分离的神经细胞内游离钙及其变化,并观测了DGAVP和Org2766对蛋白质合成抑制剂茴香霉素(ANI)引起细胞内钙离子浓度([Ca²⁺]_i)变化的影响。结果表明茴香霉素可使[Ca²⁺]_i显著升高,且有量效关系;DGAVP本身并不引起[Ca²⁺]_i发生显著变化,但适当剂量的DGAVP可显著对抗一定剂量范围内ANI升高[Ca²⁺]_i的作用,提示DGAVP对抗ANI的蛋白质合成抑制效应可能是通过拮抗ANI升高[Ca²⁺]_i这一途径实现的,另一神经肽Org2766则可能不是通过这一机制发生作用。从细胞内Ca²⁺的角度看,这两种肽的作用机理显然是不同的。     

N－甲基－N－（α－取代萘甲基）取代苄胺类化合物的合成及抗真菌活性

报道２５个Ｎ－甲基－Ｎ－（α－取代萘甲基）取代苄胺类化合物的合成及抗真菌活性。抑菌测试结果表明，目标化合物对于８种试验菌种均有不同程度的抑菌活性，化合物６，７，８，１０，１１和２１等活性为ｎａｆｔｉｆｉｎｅ的４～２０倍，化合物８，１０，１１和２１等活性为ｂｕｔｅｎａｆｉｎｅ的２～１０倍，化合物８，９，１０，１１和２１等对Ｓｐｏｒｏｔｒｉｃｈｕｍｓｃｈｅｎｃｋｉｉ及Ａｓｐｅｒｇｉｌｌｕｓｆｕｍｉｇａｔｕｓ的活性为ｃｌｏｔｒｉｍａｚｏｌｅ的８～１５倍，化合物７，８，９和２１等对Ｃｒｙｐｔｏｃｃｏｃｕｓｎｅｏｆｏｒｍａｎｓ亦表现出较高活性，ＭＩＣ为０．３１～１．２５μｇ·ｍｌ－１。     

MR imaging of the nasopharynx and floor of the middle cranial fossa. Part I. Normal anatomy

The normal anatomy of the nasopharynx and floor of the middle cranial fossa was analyzed with magnetic resonance (MR) imaging. MR images from five healthy volunteers were correlated with whole-organ cryomicrotome sections from three cadavers. Anatomic connections exist between the paranasopharyngeal spaces and the surface structures of the skull base. These anatomic connections include the intimate relationship between the eustachian tube and the pharyngobasilar fascia, the attachment of the muscles of mastication and deglutition to the skull base, and vascular and nervous structures in the foramina. The inherent contrast between the soft tissues of the nasopharynx and related structures and the bone of the floor of the middle cranial fossa allowed excellent visualization of these anatomic connections.     

Larynx and hypopharynx: MR imaging with surface coils

Forty patients with disorders of the larynx or hypopharynx were studied with magnetic resonance (MR) imaging. Axial, coronal, and sagittal sections, 4 mm thick, were obtained. Twenty-eight of the patients underwent computed tomography (CT) scanning; 17 underwent surgery, and specimens were obtained for organ sectioning. Correlation was made between these three studies as well as with clinical history, physical examination, and endoscopic photography. In 13 patients who underwent all three studies, the depiction of cartilage invasion, adenopathy, and intraorgan and extraorgan spread of disease was compared. MR consistently showed superior soft-tissue definition and extent of disease compared with CT. Neither CT nor MR was able to depict histologic detail or microscopic spread of disease. Both studies were also less effective in the postoperative or postirradiated neck. The use of direct coronal and sagittal imaging planes on MR allowed the visualization of intrinsic laryngeal musculature, which was important in the recognition of subtle tumor extension. For these reasons, surface coil MR imaging is currently the imaging study of choice at our institution for disorders of the larynx and hypopharynx.     

Granulocytic sarcoma (chloroma): CT manifestations

Nests of granulocytic tumor cells in patients who have myelogenous leukemia are termed chloromas. Eight cases of chloroma seen on CT were reviewed. Lymph nodes, subcutaneous tissues, peritoneum, pleural space, pelvis, and portal hepatis were involved. Two patients exhibited chloroma as the sole manifestation of their disease during bone marrow remission. The extracranial appearance of chloroma on CT is that of small, nonenhancing, nodular densities that resemble lymphoma. Cranial involvement is characteristically in the orbit. The central nervous system appearance is variable, however, and high attenuation masses may occur that mimic lymphoma, hematoma, and metastatic neuroblastoma. The recognition of these lesions is important, since radiation, not chemotherapy, is often the preferred treatment for localized chloroma.     

Human malignancy-associated nucleolar antigen as a marker for tumor cells in patients with acute leukemia

Tumor burden in adult patients with acute leukemia is assessed using the percentage of blast cells in the bone marrow or blood. It is clear, however, that not all blast cells are leukemic cells, especially during rapid marrow regeneration. Similarly, some leukemia cell lines have been shown to differentiate in vitro, and the same process also occurs in vivo. Therefore, the leukemic burden may be due to more differentiated cells as well as to blast cells. The purpose of this study was to investigate whether the human malignancy-associated nucleolar antigen (HMNA) could be used as a marker for leukemic cells and to examine its potential as a diagnostic tool. The proportion of HMNA-positive cells in the bone marrow of patients with acute leukemia was determined by indirect immunofluorescence with antibodies to HMNA and was compared with the differential counts routinely made in the clinic laboratory. The percentages of HMNA-positive cells among the nucleated cells in the marrow of 72 patients with clinical evidence of leukemia were significantly higher (range 9%-98%, median 83%) than those observed for nonleukemic individuals (range less than 0.05%-2.5%, median 1%) or for fractions of marrow cells from normal volunteers enriched for normal early progenitor cells (less than or equal to 2%). Patients with leukemia in remission had a lower percentage of HMNA- positive cells (range 0%-83%, median 3%). The percentage of HMNA- positive cells increased as patients approached relapse. Although the percentage of HMNA-positive cells was related to the percentage of blast cells in the bone marrow of the patients with leukemia, some partially differentiated cells were also HMNA-positive in some specimens, and some blastic cells were HMNA-negative in other specimens. These studies indicate the potential usefulness of HMNA as a marker for leukemic cells.