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PubMed1997

Oligodendrocyte precursor cells count time but not cell divisions before differentiation.

During vertebrate development, many types of precursor cell divide a limited number of times before they stop and terminally differentiate. It is unclear what limits cell proliferation and causes the cells to stop dividing when they do. The stopping mechanisms are important as they influence both the number of differentiated cells generated and the timing of differentiation. We have been studying the 'stopping' problem in the oligodendrocyte cell lineage [1] [2], which is responsible for myelination in the vertebrate central nervous system. Previous studies demonstrated that the proliferation of oligodendrocyte precursor cells isolated from the developing rat optic nerve is limited by an intrinsic 'clock' mechanism [3], which consists of two components: a counting mechanism that counts time or cell divisions, and an effector mechanism that arrests the cell cycle and initiates cell differentiation when the appropriate time is reached [4] [5]. In the present study, we address the question of whether the counting mechanism operates by counting cell divisions. We show that precursor cells cultured at 33 degrees C divide more slowly but stop dividing and differentiate sooner, after fewer cell divisions, than when they are cultured at 37 degrees C, indicating that the counting mechanism does not count cell divisions but measures time in some other way. In addition, we show that the levels of the cyclin-dependent kinase inhibitor p27(Kip1) (p27) rise faster at 33 degrees C than at 37 degrees C, consistent with previous evidence [6] that the accumulation of p27 may be part of the counting mechanism.

Animals↗

PubMed1975

Leukocyte and lymphoid cell counts in myasthenia gravis.

Serial leukocyte counts and lymphoid cell counts were compared before and after thymectomy via sternal-splitting incision in 50 patients with myasthenia gravis. Leukocyte counts and lymphoid cell counts of the thymectomized patients also were compared to those of 30 non-thymectomized myasthenic patients and 150 non-myasthenic patient controls. While mean leukocyte counts did not change significantly before and 5.5 plus or minus 5 years after thymectomy, mean lymphoid cell counts were slightly lower during this observation period post-thymectomy (t equals 1.918, p equals 0.03). Lower lymphoid cell counts appeared to correlate with a favorable response of myasthenia gravis in patients with thymic hyperplasia and mainly involuted thymus.

Adolescent↗

PubMed2005

The influence of technical factors on differential cell count in milk.

Differential cell count of milk is a traditional parameter for the evaluation of udder health. The literature shows great variation in differential cell counts of the milk of healthy mammary glands: macrophages range from 0% to 80%, lymphocytes from 1.5% to 79.5%, polymorphonuclear neutrophils from 3% to 95%, and epithelial cells from 1% to 19%. We conducted three studies to seek explanations for such variation. In the first, we evaluated the impact of polyethylene and glass sampling bottles. The aim of the second study was to compare the results of differential cell counts performed by three different technicians. The third study evaluated two methods of smear preparation. When polyethylene plastic bottles were used, the macrophage population was minimized but lymphocytes remained unaffected. This was shown by an exemplary flow cytometric analysis using four monoclonal antibodies against three lymphocyte surface structures. There were significant differences in the differential cell counts of 40 smears made by three technicians despite identical operating procedures. For the sediment smear, milk was centrifuged once and the sediment spread by eye on a glass slide. For the "coffee grinder" smear method, the sample was subjected to four centrifugations and then placed on a cover glass in order to spread the sediment using centrifugal force. The coffee grinder procedure led to a reduction of lymphocytes and an enrichment of polymorphonuclear neutrophils without affecting the macrophage population. Both methods made it possible to distinguish different udder health classes. It can be concluded that differential cell counts are a useful tool for comparing and monitoring udder health only if: samples are taken in a glass bottle; smears are prepared with the identical technique; and the differential cell counts are performed by a single person.

Animals↗

PubMed2006

Pre-mobilization therapy blood CD34+ cell count predicts the likelihood of successful hematopoietic stem cell mobilization.

We examined pre-mobilization blood CD34+ cell count to predict ability to mobilize adequate peripheral blood progenitor cells (PBPC) in 106 cancer patients and 36 allogeneic donors. Mean pre-mobilization therapy blood CD34+ cell count was 3.1 cells x 10(6)/l (s.d. = 3.9, r = 0.3-37) and mean CD34+ cells collected were 5.3 x 10(6) cells/kg/leukapheresis procedure (s.d. = 7.0, r = 0.03-53). Yields correlated with pre-mobilization CD34+ cells x 10(6)/l (r = 0.37, P-value < 0.0001); correlation was stronger in allogeneic donors (r = 0.56, P-value = 0.0004) and males (r = 0.46, P-value < 0.0001). Based on classification and regression tree multivariate analysis, the predictive value of pre-mobilization blood CD34+ cell count was confounded by other variables, including age, gender, mobilization regimen and malignancy type. We generated an algorithm to predict a minimum PBPC yield of 1 x 10(6) CD34+ cells/kg/leukapheresis procedure after mobilization. A threshold pre-mobilization blood CD34+ cell count of 2.65 cells x 10(6)/l was the most important decision point in predicting successful mobilization. Only 2% of subjects with pre-mobilization blood CD34+ cell counts > 2.65 cells x 10(6)/l did not achieve the minimum per apheresis, whereas 24% with pre-mobilization values below threshold had inadequate mobilization. Prospectively identifying individuals at risk for mobilization failure would allow for improved treatment planning, resource utilization and time saving.

Adolescent↗

PubMed2006

Sézary cell counts in erythrodermic cutaneous T-cell lymphoma: implications for prognosis and staging.

In this retrospective study, quantitative Sézary cell counts were performed at presentation on 192 patients with erythrodermic cutaneous T-cell lymphoma (E-CTCL). Per recommendation of the International Society of Cutaneous Lymphomas (ISCL), the impact on staging of using an absolute Sézary cell count of 1.0 K microL-1 or more as equivalent to lymph node involvement was investigated. Of 132 patients with disease initially classified at stage III using the current TNM staging system, 25% were up staged to IVa, resulting in a clearer separation of associated survival curves between the stages. Furthermore, the current ISCL definition of B0, B1 and B2 ratings were improved using Sézary cell count levels of < 1.0 K microL-1, > or = 1.0 - 4.99 K microL-1 and > or = 5.0 K microL-1, respectively. These modified B ratings potentially could be used in an alternative staging system for E-CTCL without N rating. Advanced age, prior exposure to multiple systemic drugs, enlargement of peripheral lymph nodes (>3 cm), other measures of blood tumor burden (CD4/CD8 ratio > or = 10, chromosomally-abnormal clone) and 2-fold increase in serum LDH level were other factors of prognostic significance. The clinical importance of these variables vis-à-vis the modified TNBM staging system will need to be clarified in future studies.

Adult↗

PubMed1999

Clinical utility in maximizing CD34+ cell count in stem cell grafts.

Many different stem cell subsets have been identified. Some of these subsets are multipotent, able to develop into any one of several cell types, while other stem cell subsets are committed to differentiated myeloid, lymphoid, erythroid, or megakaryocytic lineages.

Antigens, CD34↗

PubMed1993

Search for cell proliferation markers suitable for cell count in continuous immobilized cell bioreactors.

The control of hybridoma cell cultures in bioreactors requires the use of convenient indicators to monitor the proliferation of the biomass. In order to select appropriate indications, we followed the variations of several compounds including tumoral markers, polyamines, sialic acids, purine and pyrimidine bases, enzymes and metabolites such as glucose, lactate and amino acids, and the variations of cell density during batch culture. Significant correlations were found between the number of viable cells and alkaline phosphatase, beta-glucuronidase, glucose and lactate measured in the culture medium of hybridoma strains. The correlation calculated from alkaline phosphatase and beta-glucuronidase concentrations in culture medium underestimated cell number. The correlation established with glucose and lactate gave the best indication of cell proliferation in continuous culture with an immobilized cell bioreactor. Finally, the exact quantification of the biomass in these culture conditions can be obtained using the mean of glucose and lactate correlations.

Animals↗

PubMed1998

The prognostic significance of AgNOR counts and PCNA-positive cell counts in canine malignant lymphomas.

The behaviour of canine malignant lymphomas is difficult to predict on the basis of histomorphology alone, but the majority of such tumours are "high-grade" by most classifications. The aim of this study was to examine the prognostic significance of argyrophilic nucleolar organizer region (AgNOR) counts and of proliferating cell nuclear antigen (PCNA)-positive cell counts in canine malignant lymphomas; and to relate the results to the histological grade (Kiel classification) and to the survival time of treated and untreated dogs. Low- and high-grade malignant lymphomas differed significantly in having mean AgNOR counts of 3.3 and 5.7 respectively. Untreated dogs with a mean AgNOR count higher than 5.5 did not survive more than 85 days; the median survival time for this group was 38.5 days. Untreated dogs with a mean AgNOR count lower than 4.0 survived at least 82 days and one dog more than 300 days; the median survival time for this group was 154 days. Treated dogs with a mean AgNOR count higher than 5.5 did not survive more than 126 days; the median survival time for this group was 73.5 days. Treated dogs with a mean AgNOR count lower than 4.0 had a median survival time of 205.5 days and one dog survived 367 days. The mean AgNOR count would seem to be a valuable prognostic marker for canine malignant lymphomas, but PCNA counts had no prognostic significance in relation to the median survival time in treated or untreated dogs.

Animals↗

PubMedDate not supplied

Comparison of semiautomated method with official optical somatic cell counting method III for determining somatic cells in milk.

The new method specifying the Fossomatic-90 differs from the official method, 46.105-46.109, in that the modified instrument includes a halogen lamp; a semiconductor photoelectric detector; a less expensive, bench-top cabinet; manual injection of a larger sample, and a reduced capacity. The new instrument was compared with 2 optical somatic cell counters in routine use. On each of 3 days, 12 subsamples were prepared for each of 5 cell count levels from AM milk with half kept fresh and half preserved with 0.05% potassium dichromate. Subsamples were refrigerated and read 30+ h post-collection. Duplicate sets were read in random order on each machine daily (CV 0.77%). Two sets of slides read by 2 technicians each (strip reticle on 2 smears/slide) gave geometric mean direct microscopic somatic cell count (DMSCC) levels of 296, 526, 772, 930, and 1438 th/mL. Within-technician CV values (from day-level means) ranged from 1.68 to 2.28%. Geometric mean cells in th/mL on the new machine were significantly higher than those on the other two (674 vs 621) and were closer to the DMSCC (694). On the new machine, cell counts were 8.5% greater than on the original machines, were only 2.9% lower than the DMSCC, and showed no significant evidence of bias. Preserved samples averaged slightly greater than fresh (5.3%) but only on the original machines. Carryover by covariance analysis was insignificant. Except for cell levels, high machine precision (error CV value of 1.18%) gave differences with statistical but not practical significance, even for regulatory laboratories.

Animals↗

PubMed1991

Comparison of spinal fluid beta 2-microglobulin levels with CD4+ T cell count, in vitro T helper cell function, and spinal fluid IgG parameters in 163 neurologically normal adults infected with the human immunodeficiency virus type 1.

Beta 2-microglobulin levels were measured in the cerebrospinal fluid (CSF) and serum of 163 human immunodeficiency virus-positive (HIV+) persons with normal neurologic physical examinations. None were on antiretroviral therapy. Only 3% had a positive CSF HIV p24 antigen test. The CSF beta 2-microglobulin levels increased as the CD4+ T cell count decreased. Intrathecal production of beta 2-microglobulin was suggested by finding CSF concentrations greater than serum concentrations in 15% of patients. The CSF beta 2-microglobulin levels rose as in vitro T helper cell function deteriorated, independent of CD4+ T cell count. CSF beta 2-microglobulin levels paralleled CSF IgG, IgG index, and IgG synthesis. Higher CSF beta 2-microglobulin levels were found in persons with positive CSF oligoclonal bands. CSF beta 2-microglobulin concentration may serve as a marker for subclinical neurologic damage due to HIV. If this is established, defining the effect of anti-HIV interventions on CSF beta 2-microglobulin would be warranted.

Albumins↗

PubMed2005

An evaluation of the cell-dyn 3200 for counting cells in cerebrospinal and other body fluids.

This study compared the white blood cell (WBC) and red blood cell (RBC) counts obtained with the Cell-Dyn 3200 (CD 3200) with results obtained by hemocytometer, the reference method for counting cerebrospinal fluid (CSF) and other body fluid specimens. Ninety-six CSF and 65 body fluid specimens were evaluated. Background counts were maintained on the CD 3200 at 0.001 x 10(9)/L and 0.00 x 10(12)/L for WBC and RBC counts, respectively. Linearity and precision were acceptable for both the total nucleated cell (TNC) count and the RBC count. The CD 3200 WBC optical count was correlated with the TNC count obtained by the manual reference method for CSF specimens across the range of 0 x 10(9 )/L to 7.863 x 10(9)/L (r2 = 0.9867) and for body fluid specimens across the range of 0 x 10(9)/L to 14.0 x 10(9)/L (r2 = 0.9955). An r2 value of 0.9016 was obtained for the 82 CSF specimens with manual TNC counts of <0.200 x 10(9)/L. Analysis of the CSF and body fluid specimens indicated that automated RBC counts could be reported at > or = 0.003 x 10(12)/L. In this study, 7 CSF and 30 body fluid specimens had RBC counts of >0.003 x 10(12)/L, and there was good agreement with manual RBC counts, with r2 values of 0.9893 and 0.9960 obtained for CSF and other body fluids, respectively. The CD 3200 in our experience has a lower reportable range than the ranges of most automated cell counters reported in the literature. In contrast to the only other instrument with comparable reportable ranges, the CD 3200 requires a smaller sample volume without any special sample preparation, reagents, or software. By using the CD 3200 with our laboratory-specific rules for agreement between duplicate counts, we would be able to reduce our manual CSF specimen counts from 192 TNC and 192 RBC counts to 2 TNC and 178 RBC counts. For body fluid specimens, our manual counts would be reduced from 130 TNC and 130 RBC counts to 10 TNC and 4 RBC counts.

Blood Cell Count↗

PubMed1995

Autografting with blood progenitor cells: predictive value of preapheresis blood cell counts on progenitor cell harvest and correlation of the reinfused cell dose with hematopoietic reconstitution.

One hundred and nine patients suffering from various malignancies underwent 285 apheresis procedures for PBPC collection. A median of two leukaphereses (range: 2-5) resulted in median numbers of 4.6 x 10(8) MNC/kg, 14.1 x 10(4) CFU-GM/kg, and 6.0 x 10(6) CD34+ cells/kg. Preleukapheresis peripheral blood CD34+ cells correlated significantly with collected CD34+ cells/kg (r = 0.94; p < 0.0001) and with CFU-GM/kg (r = 0.52; p < 0.0001). A value > 4 x 10(4) CD34+ cells/ml was highly predictive for a collection yield > 2.5 x 10(6) CD34+ cells/kg harvested by a single leukapheresis. Sixty patients were evaluated for hematologic reconstitution and engrafted in a median time of 10 days for WBC > 1.0 x 10(9)/l (range: 7-21 days), 10 days for ANC > 0.5 x 10(9)/l (7-20) and 11 days for PLT > 20 x 10(9)/l (7-62). Reinfused CD34+ cells/kg correlated significantly with hematologic engraftment (r = 0.44-0.52 and p < 0.006-0.001) as well as CFU-GM/kg (r = 0.36-0.44 and p < 0.007-0.001). A progenitor cell dose > 2.5 x 10(6) CD34+ cells/kg or > 8.0 x 10(4) CFU-GM/kg led to a significantly faster recovery for WBC, ANC, and PLT when compared with patients receiving < 2.5 x 10(6) CD34+ cells/kg or < 8.0 x 10(4) CFU-GM/kg. We conclude that rapid hematopoietic engraftment after high-dose therapy and PBPC reinfusion correlates well with a progenitor cell dose > 2.5 x 10(6) CD34+ cells/kg or > 8.0 x 10(4) CFU-GM/kg, and that above a preleukapheresis threshold of 4 x 10(4) CD34+ cells/ml a PBPC autograft containing > 2.5 x 10(6) CD34+ cells/kg can be collected by a single leukapheresis. We suggest that patients recovering from myelosuppression should be monitored for CD34+ cells in serial blood samples to determine the course of circulating hematopoietic progenitor cells. This issue will help to define the optimal time point to start apheresis and to predict a PBPC autograft harvested by a single leukapheresis, which will lead to rapid and stable hematopoietic reconstitution following transplantation.

Adolescent↗

PubMed1979

Influence of storage and preservation of milk samples on microscopic and Fossomatic somatic cell counts.

Milk somatic cell counting was carried out by Fossomatic and microscopically. In unpreserved milk samples Fossomatic counts increased by up to 100% during the first 24 hours after milking. During the next 24 hours the counts increased by 5% whereafter they remained stable until at least 80 hours after milking, when the samples were stored at 5 degress C. On microscopical counting using methylene blue for staining, the results were stable from shortly after milking. In counting, attention had to be paid to the fact that within the first 24 hours a certain part of the cells would stain but faintly. After preservation with potassium bichromate the Fossomatic counts increased more rapidly. Stable results were found 5--8 hours after preservation. The final level of the Fossomatic counts was found to be app. 10% higher in preserved than in unpreserved samples. A smaller increase was found by microscopic counting. The rise of the cell counts during the first 24 hours after milking is probably due to inadequate stainability of living cells with ethidium bromide, resulting in a certain part of them being recorded by the Fossomatic. During the first day the vitality of the cells diminishes whereby they become stainable and countable. This process in hastened by potassium bichromate treatment.

Animals↗

PubMed2003

Nadir CD4+ T-cell count and numbers of CD28+ CD4+ T-cells predict functional responses to immunizations in chronic HIV-1 infection.

OBJECTIVE: To ascertain whether delaying the initiation of highly active antiretroviral therapy (HAART) compromises functional immune reconstitution in HIV-1 infection in persons who regain 'normal' CD4 T-cell counts after suppressive antiretroviral therapies. DESIGN: Prospective open-label study carried out at two University-affiliated HIV-outpatient clinics in the USA. SUBJECTS AND METHODS: Response to immunization was used as a model for in vivo functional immune competence in 29 HIV-1 infected patients with CD4 T-cell counts > 450 x 106 cells/l and HIV-RNA < 400 copies/ml for > 12 months after HAART and nine HIV-1 seronegative controls. After immunization with tetanus toxoid, diphtheria-toxoid, and keyhole limpet hemocyanin, immune response scores (IRS) were calculated using postimmunization antibody concentrations, lymphocyte proliferation, and delayed-type hypersensitivity responses to vaccine antigens. RESULTS: Despite normal numbers of circulating CD4 T-cells, the CD4 T-cell nadir before HAART initiation predicted the immune response to immunization (rho = 0.5; P < 0.005) while current CD4 T-cell count did not. Likewise, CD4 T-lymphocyte expression of the co-stimulatory molecule CD28 was also an independent predictor of response to immunization (rho = 0.5; P < 0.005). CONCLUSIONS: Even among persons who controlled HIV replication and normalized CD4 T-cell counts with HAART, pretreatment CD4 T-cell count and numbers of circulating CD4+CD28+ T-cells at immunization, but not current CD4 T-cell count, predict the ability to respond to vaccination. Delaying the initiation of HAART in chronic HIV-1 infection results in impaired functional immune restoration despite normalization of circulating CD4 T-cell numbers.

Adult↗

PubMed1985