Serum Chemokine-release Profiles in AML-patients Might Contribute to Predict the Clinical Course of the Disease.

In cancer or hematologic disorders, chemokines act as growth- or survival factors, regulating hematopoiesis and angiogenesis, determining metastatic spread and controlling leukocyte infiltration into tumors to inhibit antitumor immune responses. The aim was to quantify the release of CXCL8, -9, -10, CCL2, -5, and IL-12 in AML/MDS-pts' serum by cytometric bead array and to correlate data with clinical subtypes and courses. Minimal differences in serum-levels subdivided into various groups (e.g. age groups, FAB-types, blast-proportions, cytogenetic-risk-groups) were seen, but higher release of CXCL8, -9, -10 and lower release of CCL2 and -5 tendentially correlated with more favorable subtypes (<50 years of age, <80% blasts in PB). Comparing different stages of the disease higher CCL5-release in persisting disease and a significantly higher CCL2-release at relapse were found compared to first diagnosis - pointing to a change of 'disease activity' on a chemokine level. Correlations with later on achieved response to immunotherapy and occurrence of GVHD were seen: Higher values of CXCL8, -9, -10 and CCL2 and lower CCL5-values correlated with achieved response to immunotherapy. Predictive cut-off-values were evaluated separating the groups in 'responders' and 'non-responders'. Higher levels of CCL2 and -5 but lower levels of CXCL8, -9, -10 correlated with occurrence of GVHD. We conclude, that in AML-pts' serum higher values of CXCL8, -9, -10 and lower values of CCL5 and in part of CCL2 correlate with more favorable subtypes and improved antitumor'-reactive function. This knowledge can contribute to develop immune-modifying strategies that promote antileukemic adaptive immune responses.

Epidemiological, genetic, and clinical characterization by age of newly diagnosed acute myeloid leukemia based on an academic population-based registry study (AMLSG BiO).

We describe genetic and clinical characteristics of acute myeloid leukemia (AML) patients according to age from an academic population-based registry. Adult patients with newly diagnosed AML at 63 centers in Germany and Austria were followed within the AMLSG BiO registry (NCT01252485). Between January 1, 2012, and December 31, 2014, data of 3525 patients with AML (45% women) were collected. The median age was 65 years (range 18-94). The comparison of age-specific AML incidence rates with epidemiological cancer registries revealed excellent coverage in patients < 70 years old and good coverage up to the age of 80. The distribution according to the European LeukemiaNet (ELN) risk categorization from 2010 was 20% favorable, 31% intermediate-1, 28% intermediate-2, and 21% adverse. With increasing age, the relative but not the absolute prevalence of patients with ELN favorable and intermediate-1 risk (p < 0.001), with activating FLT3 mutations (p < 0.001), with ECOG performance status < 2 (p < 0.001), and with HCT-CI comorbidity index < 3 (p < 0.001) decreased. Regarding treatment, obesity and favorable risk were associated with an intensive treatment, whereas adverse risk, higher age, and comorbidity index > 0 were associated with non-intensive treatment or best supportive care. The AMLSG BiO registry provides reliable population-based distributions of genetic, clinical, and treatment characteristics according to age.

Long-term clinical and molecular remissions in patients with follicular lymphoma following high-dose therapy and autologous stem cell transplantation.

BACKGROUND: Long-term clinical and molecular remissions in patients with follicular lymphoma (FL) following high-dose therapy (HDT) and autologous stem cell transplantation (ASCT) have been evaluated in only a few studies. Results are especially limited for second-line HDT with BEAM (BCNU, etoposide, cytarabine and melphalan). PATIENTS AND METHODS: Sixty patients with FL received ASCT in our institution (18 first-line with total body irradiation and cyclophosphamide, 34 second-line with BEAM and 8 ≥ third-line with BEAM). In the case of long-term remission (>6 years; N = 17), peripheral blood was tested for minimal residual disease by t(14;18)- and IGH-PCR. RESULTS: Ten-year overall survival, progression-free survival and freedom from progression (FFP) after first-line ASCT were 79%, 57% and 64% after second-line ASCT 41%, 35% and 42%, respectively. Prognostic factors for FFP were treatment line and FLIPI (Follicular Lymphoma International Prognostic Index). Ten-year FFP for second-line ASCT and low-risk FLIPI was 57%, intermediate risk 37% and high risk 33%. No relapses occurred after 6 years following ASCT. Sixteen patients developed sustained long-term clinical and molecular remissions of up to 17.5 years. CONCLUSION: Sustained long-term clinical and molecular remissions can be achieved following ASCT, including HDT with BEAM in second line.

Evaluation of motility, membrane status and DNA integrity of frozen-thawed bottlenose dolphin (Tursiops truncatus) spermatozoa after sex-sorting and recryopreservation.

Artificial insemination (AI) with sex-sorted frozen-thawed spermatozoa has led to enhanced management of ex situ bottlenose dolphin populations. Extended distance of animals from the sorting facility can be overcome by the use of frozen-thawed, sorted and recryopreserved spermatozoa. Although one bottlenose dolphin calf had been born using sexed frozen-thawed spermatozoa derived from frozen semen, a critical evaluation of in vitro sperm quality is needed to justify the routine use of such samples in AI programs. Sperm motility parameters and plasma membrane integrity were influenced by stage of the sex-sorting process, sperm type (non-sorted and sorted) and freezing method (straw and directional) (P<0.05). After recryopreservation, sorted spermatozoa frozen with the directional freezing method maintained higher (P<0.05) motility parameters over a 24-h incubation period compared to spermatozoa frozen using straws. Quality of sperm DNA of non-sorted spermatozoa, as assessed by the sperm chromatin structure assay (SCSA), was high and remained unchanged throughout freeze-thawing and incubation processes. Though a possible interaction between Hoechst 33342 and the SCSA-derived acridine orange was observed in stained and sorted samples, the proportion of sex-sorted, recryopreserved spermatozoa exhibiting denatured DNA was low (6.6±4.1%) at 6 h after the second thawing step and remained unchanged (P>0.05) at 24 h. The viability of sorted spermatozoa was higher (P<0.05) than that of non-sorted spermatozoa across all time points after recryopreservation. Collective results indicate that bottlenose dolphin spermatozoa undergoing cryopreservation, sorting and recryopreservation are of adequate quality for use in AI.

Temperature dependence of the two-dimensional infrared spectrum of liquid H2O.

Two-dimensional infrared photon-echo measurements of the OH stretching vibration in liquid H2O are performed at various temperatures. Spectral diffusion and resonant energy transfer occur on a time scale much shorter than the average hydrogen bond lifetime of approximately 1 ps. Room temperature measurements show a loss of frequency and, thus, structural correlations on a 50-fs time scale. Weakly hydrogen-bonded OH stretching oscillators absorbing at high frequencies undergo slower spectral diffusion than strongly bonded oscillators. In the temperature range from 340 to 274 K, the loss in memory slows down with decreasing temperature. At 274 K, frequency correlations in the OH stretch vibration persist beyond approximately 200 fs, pointing to a reduction in dephasing by librational excitations. Polarization-resolved pump-probe studies give a resonant intermolecular energy transfer time of 80 fs, which is unaffected by temperature. At low temperature, structural correlations persist longer than the energy transfer time, suggesting a delocalization of OH stretching excitations over several water molecules.

Conversion of AML-blasts to leukemia-derived dendritic cells (DCleu) in 'DC-culture-media' shifts correlations of released chemokines with antileukemic T-cell reactions.

Dendritic cells (DC) and T-cells are mediators of CTL-responses. Autologous (from patients with acute myeloid leukaemia (AML) or myelodysplasia (MDS)) or allogeneic (donor)-T-cells stimulated by DCleu, gain an efficient lysis of naive blasts, although not in every case. CXCL8, -9, -10, CCL2, -5 and Interleukin (IL-12) were quantified by Cytometric Bead Array (CBA) in supernatants from 5 DC-generating methods and correlated with AML-/MDS-patients' serum-values, DC-/T-cell-interactions/antileukemic T-cell-reactions after mixed lymphocyte culture (MLC) and patients' clinical course. The blast-lytic activity of T-cells stimulated with DC or mononuclear cells (MNC) was quantified in a cytotoxicity assay. Despite great variations of chemokine-levels, correlations with post-stimulation (after stimulating T-cells with DC in MLC) improved antileukemic T-cell activity were seen: higher released chemokine-values correlated with improved T-cells' antileukemic activity (compared to stimulation with blast-containing MNC) - whereas with respect to the corresponding serum values higher CXCL8-, -9-, and -10- but lower CCL5- and -2-release correlated with improved antileukemic activity of DC-stimulated (vs. blast-stimulated) T-cells. In DC-culture supernatants higher chemokine-values correlated with post-stimulation improved antileukemic T-cell reactivity, whereas higher serum-values of CXCL8, -9, and -10 but lower serum-values of CCL5 and -2 correlated with post-stimulation improved antileukemic T-cell-reactivity. In a context of 'DC'-stimulation (vs serum) this might point to a change of (CCL5 and -2-associated) functionality from a more 'inflammatory' or 'tumor-promoting' to a more 'antitumor'-reactive functionality. This knowledge could contribute to develop immune-modifying strategies that promote antileukemic (adaptive) immune-responses.

Alternation of inverse problem approach and deep learning for lens-free microscopy image reconstruction.

A lens-free microscope is a simple imaging device performing in-line holographic measurements. In the absence of focusing optics, a reconstruction algorithm is used to retrieve the sample image by solving the inverse problem. This is usually performed by optimization algorithms relying on gradient computation. However the presence of local minima leads to unsatisfactory convergence when phase wrapping errors occur. This is particularly the case in large optical thickness samples, for example cells in suspension and cells undergoing mitosis. To date, the occurrence of phase wrapping errors in the holographic reconstruction limits the application of lens-free microscopy in live cell imaging. To overcome this issue, we propose a novel approach in which the reconstruction alternates between two approaches, an inverse problem optimization and deep learning. The computation starts with a first reconstruction guess of the cell sample image. The result is then fed into a neural network, which is trained to correct phase wrapping errors. The neural network prediction is next used as the initialization of a second and last reconstruction step, which corrects to a certain extent the neural network prediction errors. We demonstrate the applicability of this approach in solving the phase wrapping problem occurring with cells in suspension at large densities. This is a challenging sample that typically cannot be reconstructed without phase wrapping errors, when using inverse problem optimization alone.

Two novel peripheral membrane proteins, pasin 1 and pasin 2, associated with Na+,K(+)-ATPase in various cells and tissues.

Purification of pig kidney Na+,K(+)-ATPase at low concentrations of SDS (0.5%) allowed copurification of several peripheral membrane proteins. Some of these associated proteins were identified as components of the membrane cytoskeleton. Here we describe two novel globular proteins of of Mr 77,000 (pasin 1) and Mr 73,000 (pasin 2) which copurify and coimmunoprecipitate with Na+,K(+)-ATPase and can be stripped off Na+,K(+)-ATPase microsomes by 1 M KCl. Pasin 1 and pasin 2 were detected by immunoblot analysis in various cells and tissues including erythrocytes and platelets. Immunostaining revealed colocalization of pasin 1 and Na+,K(+)-ATPase along the basolateral cell surface of epithelial cells of kidney tubules and parotid striated ducts (titers of pasin 2 antibodies were too weak for immunocytochemistry). In erythrocytes, pasin 1 and pasin 2 are minor components bound to the cytoplasmic surface of the plasma membrane. Pasin 1 showed the same electrophoretic mobility as protein 4.1b. However, both proteins have different isoelectric points (pasin 1, pI 6; protein 4.1, pI 7), different chymotryptic fragments, and are immunologically unrelated. Short pieces of sequence obtained from pasin 1 and pasin 2 were not found in any other known protein sequence. The occurrence of pasin 1 and pasin 2 in diverse cells and tissues and their association with Na+,K(+)-ATPase suggests a general role of these proteins in Na+,K(+)-ATPase function.

Baboon infant produced by embryo transfer.

An embryo was recovered surgically from a naturally ovulating, naturally inseminated Papio cynocephalus female on day 5 of gestation and transferred surgically to a naturally synchronized, nonmated Papio cynocephalus female on 20 March 1975. A male baboon weighing 875 grams was delivered by cesarean section on 5 September 1975, 174 days after estimated ovulation time.

Maternal milk feedings reduce sepsis, necrotizing enterocolitis and improve outcomes of premature infants.

OBJECTIVE: Human milk (donor milk (DM) and/or maternal milk (MM)) feedings protect against late onset sepsis (LOS), necrotizing enterocolitis (NEC) and death. However, DM lacks many anti-infective components of MM. Therefore, we studied exclusive MM feedings to evaluate the full effect of human milk on infectious and other outcomes in premature infants. STUDY DESIGN: All infants born before 33 weeks postmenstrual age (PMA) who received exclusive (>95%) MM or exclusive preterm formula (PF) were included in this prospective investigation. RESULTS: Sixty-three infants (53%) received MM and 55 infants (47%) received PF. Both groups had similar baseline characteristics. Infants in the MM group achieved full enteral nutrition sooner (14±8 vs 19±15 days, P<0.03) and required a shorter duration of central venous lines (14±10 vs 22±21, P<0.005). Fewer infants in the MM group developed LOS (9 vs 19, P<0.05) and pneumonia (8 vs 16, P<0.05) than PF infants. Only one MM and five PF infants developed NEC (Bell stage ⩾II). Logistic regression analysis using PMA and prolonged rupture of membranes as covariates demonstrated an increased rate of NEC (odds ratio=8.85, CI=1.01 to 25.17, P=0.048) in PF infants. Periventricular leukomalacia (PVL) was more common in PF (4 vs 0, P=0.04) than in MM infants. CONCLUSION: Feedings of MM advanced more rapidly and were associated with fewer infections than PF. A possible protective effect of MM against PVL, not previously described, may be related to its immune and anti-inflammatory components.

Acute myeloid leukemia derived from lympho-myeloid clonal hematopoiesis.

We studied acute myeloid leukemia (AML) patients with lympho-myeloid clonal hematopoiesis (LM-CH), defined by the presence of DNA methyltransferase 3A (DNMT3A) mutations in both the myeloid and lymphoid T-cell compartment. Diagnostic, complete remission (CR) and relapse samples were sequenced for 34 leukemia-related genes in 171 DNMT3A mutated adult AML patients. AML with LM-CH was found in 40 patients (23%) and was associated with clonal hematopoiesis of indeterminate potential years before AML, older age, secondary AML and more frequent MDS-type co-mutations (TET2, RUNX1 and EZH2). In 82% of AML patients with LM-CH, the preleukemic clone was refractory to chemotherapy and was the founding clone for relapse. Both LM-CH and non-LM-CH MRD-positive AML patients who achieved CR had a high risk of relapse after 10 years (75% and 75%, respectively) compared with patients without clonal hematopoiesis in CR with negative MRD (27% relapse rate). Long-term survival of patients with LM-CH was only seen after allogeneic hematopoietic stem cell transplantation (HSCT). We define AML patients with LM-CH as a distinct high-risk group of AML patients that can be identified at diagnosis through mutation analysis in T cells and should be considered for HSCT.

Vertical transmission of C-type viruses: their presence in baboon follicular oocytes and tubal ova.

C-type viruses were found in baboon follicular oocytes and tubal ova adjacent to the plasma membrane in the perivitelline space or along the inner margin of the zona pellucida. Their presence support the concept of vertical transmission of C-type viruses.

Independent effects of youth and poor diabetes control on responses to hypoglycemia in children.

To evaluate the effects of childhood and poorly controlled insulin-dependent diabetes mellitus (IDDM) on counterregulatory hormone and symptomatic responses to hypoglycemia, we studied 16 nondiabetic children (13 +/- 2 yr), 19 nondiabetic adults (26 +/- 3 yr), and 13 children with IDDM (14 +/- 2 yr, HbA, 15.1 +/- 3.3%) during a gradual reduction in plasma glucose with the glucose-clamp technique. Plasma glucose was reduced from approximately 5 to approximately 2.8 mM over 240 min with serial assessment of counterregulatory hormone levels and symptom awareness. The plasma glucose level that triggered a sustained rise in plasma epinephrine was consistently higher in nondiabetic children than in adults (3.9 +/- 0.06 vs. 3.2 +/- 0.06 mM, P less than 0.001). Poorly controlled IDDM further elevated the glucose threshold for epinephrine release to normoglycemic levels (4.9 +/- 0.2 mM, P less than 0.001 vs. both control groups). Age and IDDM also produced an upward shift in the glucose level at which growth hormone release and symptom awareness were initiated. In contrast to the effect on glucose thresholds, maximal epinephrine responses and symptom scores were increased only by age and not IDDM (2-fold higher in children). We conclude that childhood and poor diabetes control independently contribute to an upward shift in glucose thresholds for counterregulatory hormone release and symptom awareness during mild hypoglycemia. Normoglycemic counterregulation may interfere with efforts to control diabetes in young patients.

Mild hypoglycemia and impairment of brain stem and cortical evoked potentials in healthy subjects.

To evaluate the impact of mild hypoglycemia on CNS function in healthy adults, we measured brain stem auditory evoked potentials and P300 potentials (elicited by cognitive processing of auditory stimuli) during hypoglycemic or euglycemic insulin clamps (80 mU.m-2.min-1). In the hypoglycemic clamp study (n = 8), plasma glucose was allowed to fall from 4.6 to 3 mM in hourly approximately 0.5-mM steps and subsequently returned to euglycemic baseline levels. In the euglycemic clamp study (n = 8), plasma glucose was maintained at baseline levels throughout. Neither brain stem nor P300 responses changed during the euglycemic control study; symptoms and counterregulatory hormones were also unaffected. During the hypoglycemia study, epinephrine and growth hormone rose once plasma glucose reached 3.4 +/- 0.1 mM. Brain stem and P300 potentials remained unchanged until the 3-mM glucose step, when neurophysiological changes suddenly developed in conjunction with reported symptoms. At this glucose level, the wave V component of the brain stem potential was selectively altered in 7 of 8 subjects. Furthermore, P300 latency significantly increased, and amplitude diminished. Changes in both brain stem and cortical (P300) responses reversed when euglycemia was restored. We conclude that modest reductions in plasma glucose (to 3 mM) produce marked alterations in both brain stem and cortical responses to auditory stimuli. These changes in neural function appear at the same time as symptoms and follow rather than precede the rise in counterregulatory hormones during hypoglycemia. Our data suggest that the adverse effects of mild hypoglycemia on brain function are not limited to higher centers but also involve the brain stem.

Delayed sodium thiosulfate as an otoprotectant against carboplatin-induced hearing loss in patients with malignant brain tumors.

Carboplatin is effective in the treatment of malignant brain tumors. However, when administered in conjunction with osmotic opening of the blood-brain barrier (BBB), carboplatin is ototoxic. The purpose of this study was to determine whether delayed administration of sodium thiosulfate (STS), given after BBB closure, provided protection against carboplatin ototoxicity. Patients underwent monthly treatment with intra-arterial carboplatin (200 mg/m2/day x 2) in conjunction with osmotic opening of the BBB, for up to 1 year. Audiological assessment was conducted at baseline and within 24 h before each monthly treatment. STS was administered i.v. as one (20 g/m2) or two (20 g/m2 and 16 g/m2) 15-min doses, depending on baseline hearing status. The initial group received the first STS dose 2 h (or 2 and 6 h) after carboplatin (STS2) and a subsequent group received STS 4 h (or 4 and 8 h) after carboplatin (STS4). Audiological data were compared with a historical comparison group (HCG) treated with carboplatin without STS. Spearman correlation coefficients comparing STS 2 (n = 24), STS4 (n = 17), and HCG (n = 19) indicated significantly lower rates of ototoxicity with increased delay in STS (P = 0.0006). On the basis of the analysis of hearing levels, there were significant differences among the two STS groups and HCG at 8000 Hz (P = 0.0010) and at 4000 Hz (P = 0.0075). The log-rank test for time to ototoxicity indicated a significant difference between STS4 and HCG (P = 0.0018). Delayed STS was effective in protecting against carboplatin-induced hearing loss. STS delayed to 4 h after carboplatin significantly decreased time to development of ototoxicity and rate of ototoxicity when compared with HCG.

The potential of ki67 and p53 assessment in development of individualized targeted therapy in breast cancer patients.

INTRODUCTION: Despite the improvement of diagnostic methods and chemotherapeutic regimens in breast cancer, overall 5-year survival significantly depends on the stage of the disease. Over expression of tumor suppressor gene p53 and the marker for cellular proliferation Ki67 in breast cancer may have prognostic significance. METHODS: We evaluated 675 patients diagnosed with breast cancer at UF Health Jacksonville between January 2000 and June 2007 with up to 5-year follow up. The aim of the study was to determine whether immunohistochemical (IHC) assessment of Ki67 and p53 may predict outcome, the 'hazard' of dying. Cox's proportional hazards models were used to control for age (< 50 vs. ≥ 50), race (white vs. other), lymph node group (negative vs. positive), ER (estrogen receptor) group (negative vs. positive), PR (progesterone receptor) group (negative vs. positive), and tumor type. RESULTS: When only p53 was considered in the model, the hazard of dying was significantly higher for p53 positive compared to p53 negative (HR = 1.32, 95% CI 1.02, 1.70, p = 0.036). When only ki67 was considered in the model, the hazard of dying was significantly higher for ki67 positive compared to ki67 negative (Hazard ratio = 1.64, 95% CI 1.08, 2.49, p = 0.021). Neither of the two markers, nor their interaction was significant when all variables were considered in the model. DISCUSSION: This study confirms the expression of p53 and Ki67 as strong individual indicators of patient outcome. However, when controlling for the other variables, the two markers are not independent predictors. Future studies that will include these markers might help design targeted therapy.

Radiofrequency Volumetric Thermal Ablation of Fibroids and Laparoscopic Myomectomy: Long-Term Follow-up From a Randomized Trial.

Aims: Laparoscopic myomectomy (LM) has been the gold standard treatment for uterine fibroids in women desiring uterine conservation. To evaluate a new fibroid treatment modality - radiofrequency volumetric thermal ablation (RFVTA) - we compare 12-month results in women who had symptomatic uterine fibroids and who were randomized to laparoscopic ultrasound-guided RFVTA or LM. Materials and Methods: Our study is a 1 : 1 parallel, randomized, prospective, single-center, longitudinal, comparative analysis of RFVTA to LM for fibroid treatment in women ≥ 18 years of age who desired uterine conservation. Fifty women were randomized intraoperatively to RFVTA (n = 25) or to LM (n = 25) after laparoscopic ultrasound mapping of the uterus. Results: Post surgery, ablation and myomectomy subjects took pain medications for 4 days (range: 1-46) and 7 days (range: 1-83 days) respectively (p = 0.60). Ablation and myomectomy subjects missed 10.0 workdays (range: 2-86 days) and 17.0 workdays (range: 7-30 days) (p = 0.28), resumed normal activities in 20.5 days (range: 5-103 days) versus 28.0 days (range: 10-42 days) (p = 0.86) respectively. Mean symptom severity scores decreased (improved) by - 7.8 for the ablation subjects and by - 17.9 for the myomectomy subjects (p = 0.16). Health-related quality of life improved (increased) by 7.5 and 13.1, respectively, for the two groups (p = 0.46). Two myomectomy subjects had pregnancies that ended in a Cesarean delivery and a vaginal delivery of healthy infants. Two pregnancies in the RFVTA group ended in full-term vaginal deliveries of healthy infants. Conclusions: Early postoperative recovery and twelve-month results attest to similar clinical benefits from RFVTA and LM.

Mrnp41 (Rae 1p) associates with microtubules in HeLa cells and in neurons.

Mrnp41 (hRae1p) is an evolutionarily highly conserved protein, which is a potential component of mRNP particles and plays a role in nuclear mRNA export. The protein is mainly localized at the nuclear pore complex, but is also associated with distinct nuclear domains and with a meshwork of numerous small particles in the cytoplasm (Kraemer and Blobel (1997): Proc. Natl. Acad. Sci. USA 91, 1519-1523). We show that the cytoplasmic pattern of mrnp41 is sensitive to treatment with the microtubule (MT)-depolymerizing drug nocodazole which causes disappearance of mrnp41 from the cell periphery and concentration around the nucleus. By immunofluorescence we demonstrate that mrnp41 colocalizes with MT in HeLa cells and displays an MT-like distribution in cultured neurons. Association of mrnp41 with MT is further demonstrated by copurification with MT from pig brain throughout several steps of polymerization and depolymerization. Separation of MT-associated proteins (MAPs) by phosphocellulose (PC) chromatography showed copurification of mrnp41 with MAPs. These data show an association of mrnp41 with MT and, moreover, demonstrate that an intact MT system is necessary for dispersion of mrnp41-containing particles to the cellular periphery. The essential role of mrnp41 in spindle pole separation and cell cycle progression may also be related to its ability to bind to MTs.

Demonstration of immunoreactive forms of erythrocyte protein 4.2 in nonerythroid cells and tissues.

Protein 4.2 is a major component of the erythrocyte membrane cytoskeleton. Here we show that immunoreactive forms of human (Mr 72,000) and pig (Mr 75,000) protein 4.2 are also associated with the plasma membrane of various nonerythroid cells and tissues, such as platelets, brain, and kidney. Protein 4.2 can be extracted from platelet membranes under the same conditions (pH 11, 1 M KI, 1 M urea) which are required to extract protein 4.2 from the erythrocyte plasma membrane. The demonstration of protein 4.2 in nucleated cells that contain also several other proteins of the erythrocyte membrane cytoskeleton indicates some general principles underlying the molecular construction of the plasma membrane in erythrocytes and nonerythroid cells.

Association of kidney and parotid Na+, K(+)-ATPase microsomes with actin and analogs of spectrin and ankyrin.

Kidney Na+,K(+)-ATPase has been recently shown to bind erythroid ankyrin and to colocalize with ankyrin at the basolateral cell surface of kidney epithelial cells. These observations suggest that Na+,K(+)-ATPase is linked via ankyrin to the spectrin/actin-based membrane cytoskeleton. In the present study we show that Na+,K(+)-ATPase and analogs of spectrin, ankyrin and actin copurify from detergent extracts of pig kidney and parotid gland membranes. Actin, spectrin and ankyrin were extracted from purified Na+,K(+)-ATPase microsomes at virtually identical conditions as their counterparts from the erythrocyte membrane, i.e., 1 mM EDTA (spectrin, actin) and 1 M KCl (ankyrin). Visualization of the stripped proteins by rotary shadowing revealed numerous elongated spectrin-like dimers (100 nm) and tetramers (215 nm), a fraction of which (17%) was associated with globular (10 nm) ankyrin-like particles. Like erythrocyte ankyrin, kidney ankyrin was cleaved into a soluble 72 kDa fragment and a membrane-bound 90 kDa fragment. Consistent with our previous immunocytochemical findings on the pig kidney, Na+,K(+)-ATPase and ankyrin were found to be colocalized at the basolateral plasma membrane of striated ducts and acini of the pig parotid gland. The present findings confirm and extend the recently proposed concept that in polarized epithelial cells Na+,K(+)-ATPase may serve as major attachment site for the spectrin-based membrane cytoskeleton to the basolateral cell domain. Connections of integral membrane proteins to the cytoskeleton may help to place these proteins at specialized domains of the cell surface and to prevent them from endocytosis.