Phenotypic and functional analysis of CD4+ NKRP1A+ human T lymphocytes. Direct evidence that the NKRP1A molecule is involved in transendothelial migration

In this report, we show that among human CD4+ T lymphocytes 5-20% express the C-type lectin molecule NKRP1A. This lymphocyte subset displays a slightly more limited T cell receptor V beta repertoire than the CD4+ NKRP1A- counterpart. CD4+ NKRP1A+ T lymphocytes are characterized by a high expression of beta 1 and beta 2 integrins, thus representing a T lymphocyte subset that can possibly adhere and migrate through vascular endothelium. Indeed, resting CD4+ NKRP1A+ lymphocytes, differently from the CD4+ NKRP1A- subset, migrated across endothelial cell monolayers in a Transwell chamber system. Pretreatment of CD4+ NKRP1A+ T lymphocytes with an anti-NKRP1A monoclonal antibody (mAb) strongly reduced transendothelial migration, suggesting the involvement of the NKRP1A molecule in the transmigration process. Furthermore, cells of the NKRP1A- Jurkat CD4+ T cell line stably transfected with NKRP1A cDNA migrated more rapidly and efficiently than either untransfected or mock-transfected Jurkat cells. Finally, mAb-mediated cross-linking of NKRP1A molecules in CD4+ T lymphocytes induced the up-regulation of the lymphocyte function-associated antigen 1 Mg(2+)-binding site as well as beta 1 and beta 2 integrin chains. Altogether, these findings suggest that the NKRP1A molecule is involved in transendothelial migration of resting CD4+ T lymphocytes.     

19-nor vitamin-D analogs: a new class of potent inhibitors of proliferation and inducers of differentiation of human myeloid leukemia cell lines

We have studied the in vitro biological activities and mechanisms of action of 1,25-dihydroxyvitamin D3 (1,25D3) and nine potent 1,25D3 analogs on proliferation and differentiation of myeloid leukemia cell lines (HL-60, retinoic acid-resistant HL-60 [RA-res HL-60], NB4 and Kasumi-1). The common novel structural motiff for almost all the analogs included removal of C-19 (19-nor); each also had unsaturation of the side chain. All the compounds were potent; for example, the concentration of analogs producing a 50% clonal inhibition (ED50) ranged between 1 x 10(-9) to 4 x 10(-11) mol/L when using the HL-60 cell line. The most active compound [1, 25(OH)2-16,23E-diene-26-trifluoro-19-nor-cholecalciferol (Ro 25-9716)] had an ED50 of 4 x 10(-11) mol/L; in contrast, the 1,25D3 produced an ED50 of 10(-9) mol/L with the HL-60 target cells. Ro 25-9716 (10(-9) mol/L, 3 days) was a strong inducer of myeloid differentiation because it caused 92% of the HL-60 cells to express CD11b and 75% of these cells to reduce nitroblue tetrazolium (NBT). This compound (10(-8) mol/L, 4 days) also caused HL-60 cells to arrest in the G1 phase of the cell cycle (88% cells in G1 v 48% of the untreated control cells). The p27(kip-1), a cyclin-dependent kinase inhibitor which is important in blocking the cell cycle, was induced more quickly and potently by Ro 25-9716 (10(-7) mol/L, 0 to 5 days) than by 1,25D3, suggesting a possible mechanism by which these analogs inhibit proliferation of leukemic growth. The NB4 promyelocytic leukemia cells cultured with the Ro 25-9716 were also inhibited in their clonal proliferation (ED50, 5 x 10(-11) mol/L) and their expression of CD11b was enhanced (80% positive [10(-9) mol/L, 4 days] v 27% untreated NB4 cells). Moreover, the combination of Ro 25-9716 (10(-9) mol/L) and all-trans retinoic acid (ATRA, 10(-7) mol/L) induced 92% of the NB4 cells to reduce NBT, whereas only 26% of the cells became NBT positive after a similar exposure to the combination of 1,25D3 and ATRA. Surprisingly, Ro 25-9716 also inhibited the clonal growth of poorly differentiated leukemia cell lines (RA-res HL-60 [ED50, 4 x 10(-9) mol/L] and Kasumi-1 [ED50, 5 x 10(-10) mol/L]). For HL-60 cells, Ro 25-9716 markedly decreased the percent of the cells in S phase of the cell cycle and increased the expression of the cyclin-dependent kinase inhibitor, p27(kip-1). In summary, 19-nor vitamin D3 compounds strongly induced differentiation and inhibited clonal proliferation of various myeloid leukemia cell lines, suggesting a therapeutic niche for their use in myeloid leukemia.     

Observations on the turkey oviductal sperm-storage tubule using differential interference contrast microscopy

Squash preparations of unfixed, uterovaginal junction mucosae revealed that openings to sperm-storage tubules were round or slit-like and were surrounded by either cilia, which were part of the uterovaginal junction surface epithelium, or nonciliated cells resembling the sperm-storage tubule epithelium. By focusing on different levels of the sperm-storage tubule (optical sectioning), connective tissue fibres and cells between individual sperm-storage tubules, epithelium and lumen of sperm-storage tubules containing resident spermatozoa were observed. An optical section through the sperm-storage tubule epithelium revealed basal nuclei and associated nucleoli, and refractile supranuclear lipid droplets. Luminal spermatozoa were distributed primarily in the distal third of the sperm-storage tubule and nearly always formed a tight bundle at its base. These spermatozoa were often observed slowly and synchronously oscillating. In two-thirds of the 30-week-old, non-photostimulated hens, sperm-storage tubules were fully formed. In contrast, the remaining hens possessed bud-like surface invaginations lacking discernible lumina. It was concluded that differential interference contrast microscopy offers better spatial and optical resolution of the sperm-storage tubule than other modes of light microscopy.     

Reversal by desferrioxamine of tau protein aggregates following two days of treatment in aluminum-induced neurofibrillary degeneration in rabbit: implications for clinical trials in Alzheimer''s disease

Concern about possible transmission of bloodborne pathogens during medical procedures is growing among patients and healthcare workers alike. This fear has primarily been focused on nosocomial transmission of human immunodeficiency virus (HIV), but other bloodborne infectious agents may also be transmitted during procedures. Chief among these are the hepatitis viruses, particularly hepatitis B virus (HBV) and hepatitis C virus (HCV), both of which are significantly more widespread than HIV. Although radiology is not traditionally thought of as a field with significant risk for exposure to or transmission of pathogens, the expanding role of interventional procedures in recent years belies that perception. The potential for exposure to blood or other possibly infectious material exists in virtually any invasive radiological procedure, from arteriography to image-guided biopsy. Fortunately, the risk of such exposure is low, and the risk of actual transmission of a bloodborne pathogen, whether from patient to healthcare worker or vice versa, is even lower. Nevertheless, it is important for all radiologists who perform invasive procedures to be aware of these risks and to observe pertinent safety and infection control recommendations. This article will review these topics.     

Severe non-ketotic hyperosmolar coma--intensive care management

We prospectively studied 266 hands in 133 patients with carpal tunnel syndrome (CTS) in order to evaluate: the incidence of bilateral CTS symptoms; correlation between severity, duration of symptoms and bilateral occurrence of CTS; agreement of clinical and neurophysiological findings; and the neurophysiological findings in asymptomatic hands in unilateral CTS. The incidence of bilateral clinical CTS in our population was 87%. Neurophysiological impairment of median nerve was observed in about half of the asymptomatic hands. Follow-up of patients with unilateral CTS showed that contralateral symptoms developed in most cases. We found a significant positive correlation of bilateral CTS with the duration of symptoms, whereas there was no correlation with the severity of symptoms. Our data suggest that bilateral impairment of median nerve is the rule in patients with CTS and probably it has been underestimated in previous studies.     

Reaction of different cell populations in mouse thymus to a single gamma-irradiation

Acute care facilities are no longer viewed as the center of the health care network. Efforts to reduce hospital length of stay will continue to spur the growth of care delivered in homes. With the downsizing of many hospitals, the need for nurses in acute care settings will decline. Many acute care nurses are finding themselves seeking employment opportunities in home health care settings. The purpose of this study was to examine nurses' experiences when they change from hospital-based practice to home health care nursing. The qualitative mode of inquiry was used to conduct taped-recorded interviews of 25 baccalaureate-prepared nurses in a large metropolitan area. Stressors experienced by the nurses were identified as well as adaptations required to minimize role stress. Continuing education programs can provide information and skills needed to improve nurses' competencies to function in a health care system projected to be more community-based, which includes home health care.     

Use of digitalis glycosides to identify the mechanisms of amantadine transport by renal tubules

The mechanism(s) for uptake of organic cations by renal cortical tubules was (were) examined further. Renal cortical tubules were purified from rat kidneys by a Percoll gradient centrifugation technique. Bicarbonate buffer (Krebs-Henseleit, KHS) conditions were altered, and chemical modulators were used which affect the activity of the basolateral Na+/K+-ATPase. Renal tubule uptake of the achiral organic cation amantadine was determined. The cardiac glycosides digoxin and acetylstrophanthidin and ouabagenin did not alter amantadine uptake by either proximal or distal tubule fragments in KHS. However, ouabain inhibited proximal tubule amantadine uptake in a dose-dependent manner with lower potency than distal tubule amantadine uptake in KHS. Ouabain did not inhibit amantadine tubule uptake in phosphate buffer. However, inhibition of amantadine uptake by ouabain returned in a time-dependent manner upon addition of bicarbonate to the phosphate buffer. Low extracellular sodium or potassium did not alter amantadine uptake by proximal tubules. Hypokalemic and hypokalemic/ hyponatremic conditions decreased the inhibitory potency of ouabain for amantadine uptake by proximal tubules. For distal tubules, both hyponatremic and hypokalemic conditions, alone and together, decreased the inhibitory potency of ouabain, but did not affect amantadine uptake in the absence of ouabain. Hypochloremic conditions decreased affinity for amantadine uptake by distal, but not proximal tubules. No change in maximal transport capacity for amantadine uptake was observed under hypochloremic conditions for either tubule fragment. These studies challenge the widely accepted concept of Na+/ K+-adenosine triphosphatase activity and maintenance of the basolateral membrane potential as rate-limiting steps for the energy-dependent renal tubule uptake of organic cations. Furthermore, these studies suggest a mechanism for ouabain inhibition of organic cation renal tubule uptake that may not involve the Na+/K+-adenosine triphosphatase and may be possibly bicarbonate-dependent.     

The HIV-inactivating protein, cyanovirin-N, does not block gp120-mediated virus-to-cell binding

Concentrations of the potent, HIV(human immunodeficiency virus) inactivating protein, cyanovirin-N (CV-N), which completely inhibit HIV-1 infectivity, do not block the binding of soluble CD4-receptor (sCD4) to HIV-1 lysates nor the attachment of intact HIV-1 virions to several target T-cell lines. Furthermore, in contrast to the known disassociative effects of sCD4 on viral envelope glycoproteins, treatment of HIVRF with high concentrations of CV-N results in complete viral inactivation but without apparent shedding of gp120 or other ultrastructural changes. These results are consistent with the view that the virucidal effects of CV-N result from interference with step(s) in the fusion process subsequent to the initial binding of the virus to target cells.