High Cell Content Research Articles

Carbon and nitrogen fluxes associated with the cyanobacterium Aphanizomenon sp. in the Baltic Sea

Carbon and nitrogen fluxes in Aphanizomenon sp. colonies in the Baltic Sea were measured using a combination of microsensors, stable isotopes, mass spectrometry, and nanoscale secondary ion mass spectrometry (nanoSIMS). Cell numbers varied between 956 and 33 000 in colonies ranging in volume between 1.4 x 10(-4) and 230 x 10(-4) mm(-3). The high cell content and their productivity resulted in steep O(2) gradients at the colony-water interface as measured with an O(2) microsensor. Colonies were highly autotrophic communities with few heterotrophic bacteria attached to the filaments. Volumetric gross photosynthesis in colonies was 78 nmol O(2) mm(-3) h(-1). Net photosynthesis was 64 nmol O(2) mm(-3) h(-1), and dark respiration was on average 15 nmol O(2) mm(-3) h(-1) or 16% of gross photosynthesis. These volumetric photosynthesis rates belong to the highest measured in aquatic systems. The average cell-specific net carbon-fixation rate was 38 and 40 fmol C cell(-1) h(-1) measured by microsensors and by using stable isotopes in combination with mass spectrometry and nanoSIMS, respectively. In light, the net C:N fixation ratio of individual cells was 7.3+/-3.4. Transfer of fixed N(2) from heterocysts to vegetative cells was fast, but up to 35% of the gross N(2) fixation in light was released as ammonium into the surrounding water. Calculations based on a daily cycle showed a net C:N fixation ratio of 5.3. Only 16% of the bulk N(2) fixation in dark was detected in Aphanizomenon sp. Hence, other organisms appeared to dominate N(2) fixation and NH(4)(+) release during darkness.

A Hierarchy of Self-Renewing Tumor-Initiating Cell Types in Glioblastoma

The neural stem cell marker CD133 is reported to identify cells within glioblastoma (GBM) that can initiate neurosphere growth and tumor formation; however, instances of CD133(-) cells exhibiting similar properties have also been reported. Here, we show that some PTEN-deficient GBM tumors produce a series of CD133(+) and CD133(-) self-renewing tumor-initiating cell types and provide evidence that these cell types constitute a lineage hierarchy. Our results show that the capacities for self-renewal and tumor initiation in GBM need not be restricted to a uniform population of stemlike cells, but can be shared by a lineage of self-renewing cell types expressing a range of markers of forebrain lineage.

Dendritic Cell Count in the Graft Predicts Relapse in Patients with Hematologic Malignancies Undergoing an HLA-Matched Related Allogeneic Peripheral Blood Stem Cell Transplant

We investigated the impact of the number of infused and reconstituted immunocompetent cells including dendritic cells (DCs) on clinical outcome of patients with hematologic malignancies undergoing an allogeneic peripheral blood stem cell transplantation. Sixty-nine consecutive patients with hematologic malignancies were included in the analysis. The median age of the cohort was 32 years (range: 2-62 years) and there were 39 (57%) males. Twenty-one (30%) patients relapsed with a cumulative incidence of 44 % +/- 14% at a median follow up of 28 months. On a multivariate analysis, a high plasmacytoid dendritic cell (PC) content in the graft was associated with higher risk of relapse. The patients were further categorized based on the median PC counts in the graft as high (> or =2.3 x 10(6)/kg) and low (<2.3 x 10(6)/kg) groups. The baseline characteristics of these 2 groups were comparable. The group that had a high PC content in the graft had significantly higher risk of relapse and lower overall survival (OS) and event-free survival (EFS). Our data suggests that PC content in the graft predicts clinical outcomes such as relapse and survival in patients with hematologic malignancies undergoing an allogeneic HLA matched related peripheral blood stem cell transplantation. There is potential for pretransplant manipulation of this cellular subset in the graft.

Acoustic Whole Blood Plasmapheresis Chip for Prostate Specific Antigen Microarray Diagnostics

The generation of high quality plasma from whole blood is of major interest for many biomedical analyses and clinical diagnostic methods. However, it has proven to be a major challenge to make use of microfluidic separation devices to process fluids with high cell content, such as whole blood. Here, we report on an acoustophoresis based separation chip that prepares diagnostic plasma from whole blood linked to a clinical application. This acoustic separator has the capacity to sequentially remove enriched blood cells in multiple steps to yield high quality plasma of low cellular content. The generated plasma fulfills the standard requirements (<6.0 x 10(9) erythrocytes/L) recommended by the Council of Europe. Further, we successfully linked the plasmapheresis microchip to our previously developed porous silicon sandwich antibody microarray chip for prostate specific antigen (PSA) detection. PSA was detected by good linearity (R(2) > 0.99) in the generated plasma via fluorescence readout without any signal amplification at clinically relevant levels (0.19-21.8 ng/mL).

Interlaboratory assay reproducibility study for loss of heterozygosity on chromosome 18 (18q LOH) in colon cancer

4052 Background: 18q LOH may be a useful marker in stage II colon carcinoma to assess who needs adjuvant chemotherapy. The objective of this study was to evaluate the intra- and inter-laboratory reproducibility of an assay for 18q LOH that is similar to the integral assay used in E5202, the current Intergroup phase III stage II colon carcinoma clinical trial. Methods: Specimens from 130 stage II/III colon cancer patients were obtained from the Cooperative Human Tissue Network and evaluated at three different laboratories. Samples were divided into subsamples, coded and distributed. Each laboratory used similar equipment in an established PCR protocol with 5 dinucleotide repeats. Starting materials used both histologic sections and extracted DNA samples of tumor and non-neoplastic tissue obtained only by scalpel microdissection. LOH was defined as tumor/normal peak ratio that was &gt;1.35 or &lt;0.67 without microsatellite instability (MSI). Tumors were categorized as either MSI+, LOH + or -, uninformative/monoallelic, or unevaluable (DNA not amplifiable). Standard tests assessed reproducibility of both the numerical ratios and the tumor 18q LOH status. Results: Sample quality issues prevented analysis of 13 tumors (10%). The frequency of 18q LOH was 64%. The probability of agreement on the same tumor evaluated twice was 92% (Cohen's kappa 0.83). Intra-class correlation coefficients for individual markers were consistently over 0.90. Tissue specimens must have high (&gt;85%) tumor cell content for reproducibility. Differences among patients affected reproducibility much more than effects of laboratory and sample type (DNA vs. histologic section). Conclusions: This study validates reproducibility of the 18q LOH assay for both clinical categorization of status and numerical ratios if samples are high quality and appropriate for scalpel microdissection. [Table: see text]

Epidemiological Studies on Subclinical Mastitis in Dairy cows in Assiut Governorate

In this investigation, some epidemiological studies were run on subclinical mastitis for totally 350 dairy cows of different breeds, ages and distributed in different villages in Assiut governorate, Assiut, Egypt, along a whole year (during the period from June 2006 till July 2007) through field screening surveys by using of the California mastitis test (CMT) for each quarter milk sample followed by bacteriological examination to identify the major causative agents of intramammary infection (IMI). The dairy cows were differed from the breed point of view as 230 Holstein Friesian breed and 120 native breed. Also, they were differed from the age point of view as a group of 95 cows aged from 2 to 4 years old and another group of 255 cow aged from 5 to 8 years old. All dairy cows were apparently healthy with clinically sound udder secreting apparently normal milk. All the cows lived nearly under the same conditions of breeding from the habitat, hygiene and feeding systems. The obtained results revealed that 67 cows (19.14%) had 80 infected quarters (5.71%). It was found that the most frequently major causative agents isolated were Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli from the positive CMT samples with prevalence 52.5, 31.25 and 16.25%, respectively. With studying the breed factor, it was found Friesian breed was sensitive towards infection (20.43% at the cow level and 6.09% at the quarter level) than of native breed (16.67% at the cow level and 5% at the quarter level). It was also noticed that the prevalence of subclinical mastitis in hot weather as during summer (9.14% at the cow level and 2.64% at the quarter level) and during spring (4.86% at the cow level and 1.36% at the quarter level) was higher than in cold weather as during winter (2% at the cow level and 0.64% at the quarter level) and during autumn (3.14% at the cow level and 1.07% at the quarter level). In relation to age susceptibility, 5-8 years old cows (15.43% at the cow level and 4.36% at the quarter level) were susceptible than those of 2-4 years (3.71% at the cow level and 1.36% at the quarter level). The degree of quarter attack according to positive CMT was varied from 35 quarters (2.50%) showed degree (+++), to 45 ones (3.22%) showed degree (++), to 120 ones (8.57%) showed degree (+) and the rest (85.71%) showed degree (-). The obtained results threw the light on the epidemiology of subclinical mastitis in Assiut villages and provided an importance of the CMT for diagnosis of subclinical mastitis due to it is a reliable, easy, rapid and cheap tool helping in diagnosis and controlling the disease because it directs attention to individual mammary quarter that is secreting milk of high somatic cell content (SCC). Programs for control of subclinical mastitis may be planned around the routine examination of all lactating cows, and consequently early treatment can be applied towards positive cases rapidly for preventing their conversion towards clinical form among dairy cows and for protecting the herd health, milk hygiene and consequently the consumer health.

Prognostic Impact of Microvessel Density in Follicular Lymphoma Patients Treated with Immunochemotherapy

Tumor infiltrating mast cells have at least two potential roles in remodeling tumor microenvironment and tumor growth: suppression of immune responses and potentiation of angiogenesis. We have recently shown that accumulation of mast cells in follicular lymphoma (FL) contributes to unfavorable survival after immunochemotherapy. Interestingly, high mast cell content eliminates the positive prognostic value of tumor-associated macrophages (TAMs). Here we investigated whether tumor vascularity, as determined by CD31 immunostaining, is associated with mast cell content and outcome of primary FL patients treated with combination of rituximab (R) and CHOP chemotherapy. We found that increased microvessel density (MVD) correlates positively with the number of tumor infiltrating mast cells (r=0.266, p=0.011). In a cohort of 95 patients, the patients with high MVD (>the lowest tertile) had a worse 4-year progression free survival (PFS) (44% vs 82%, p=0.001). In multivariate analysis with FLIPI, MVD retained its negative predictive value. Additional prognostic impact was especially provided in patients with low FLIPI scores. When MVD related outcome was estimated separately for patients with high and low mast cell contents, the adverse effect of high MVD on the PFS was seen in both subgroups. Taken together, the data demonstrate that MVD is associated with mast cell content and adverse outcome in R-CHOP treated FL patients. In contrast to TAMs, the predictive value of MVD is independent of tumor infiltrating mast cells.

Combined FOXP3+ and PD1+ T Cell Density and Architectural Patterns Predict Overall Survival and Risk of Transformation in Uniformly Treated Patients with Follicular Lymphoma

Background: Follicular lymphoma (FL) is an indolent heterogeneous lymphoid neoplasm with a variable clinical course. Transformation into an aggressive lymphoma is a dominant clinical event frequently associated with inferior survival. No consistent biological markers are predictive of survival or risk of transformation (RT). Recent studies have highlighted the role of the microenvironment, including regulatory T cells (Treg) as important prognostic factors in FL. Using tissue microarrays (TMA), we previously identified FOXP3+ T cell distribution but not cell density within the tumor is an independent adverse prognostic factor for both overall survival (OS), progression-free (PFS) survival and RT in advanced-stage FL pts treated uniformly with an aggressive treatment regimen (ASH 2007). Programmed death-1(PD1) belongs to the immunoglobulin CD28 receptor family and is characteristically expressed by germinal center associated T cells. They have imunoregulatory activity and are FOXP3-negative. Using the same cohort we assessed the role of PD1+ cells alone and in combination with FOXP3+ cells in FL prognosis.Methods: Between 1987 and 1993, 126 pts were enrolled on a phase II study of BP-VACOP chemotherapy with involved region radiotherapy. All patients were treatment naive, < 61y and had advanced-stage FL. Paraffin blocks were available for 105 pts. TMAs consisted of duplicate 1.0mm cores of diagnostic biopsies and were immunostained with both FOXP3 and PD1 (NAT105) specific antibodies. Both cell content and immuno-architectural patterns were determined and correlated with OS and RT including univariate and multivariate analysis.Results: There were 101 evaluable cases. The median follow-up of the living pts was 14 years. Histologic grade included 78 grade 1, 17 grade 2 and 6 grade 3a FLs. The IPI was predictive of OS (RR = 2.5, 95% CI =1.5–4.4, p = 0.002), but not RT (p = 0.14). Cases revealed zero to 731 FOXP3+ cells per core (median of 242 cells per core) and zero to 654 PD1+ cells per core (median of 102 cells per core). There was a predominantly intrafollicular or perifollicular localization of positive cells (“follicular pattern”) in 38 and 43 pts for FOXP3 and PD1, respectively. There was no significant correlation between cell density (χ2=0.1) or pattern (χ2=0.8) between markers. Separately, cell density did not impact prognosis. Yet, when quartiles were combined and dichotomized, cases with high cell content of FOXP3+/PD1+ cells correlated with inferior OS and increased RT in univariate (p = 0.002 and p = 0.01) and multivariate Cox models (RR = 2.18, 95% CI =1.2–3.9, p = 0.01 & RR = 3.4, 95% CI =1.3–8.8, p = 0.015). In univariate analysis, a PD1 follicular pattern correlated with inferior OS (p=0.027) but did not impact RT. When combined with follicular FOXP3+ cases, a subset of 15 “double follicular” FOXP3 & PD1 cases correlated with inferior OS in univariate (p=0.0016) and multivariate Cox models (RR = 2.1, 95% CI =1–4.3, p = 0.04). This subset of cases also showed a trend for increased RT (p = 0.09).Conclusions: Combined cell density and distribution within FL of immuno-regulatory T cell subsets are important predictors of OS & RT in advanced-stage FL patients treated uniformly with an aggressive treatment regimen. Our results reinforce the importance of the microenvironment in FL biology and further suggest an active role for immuno-modulatory T cells in pro-tumoral immunity.

MicroRNA-Mediated Inhibition of Prostate-Derived Ets Factor Messenger RNA Translation Affects Prostate-Derived Ets Factor Regulatory Networks in Human Breast Cancer

Prostate-derived Ets factor (PDEF) is an ETS transcription factor expressed in normal tissues with high epithelial cell content and noninvasive breast cancer cells. A putative tumor suppressor PDEF protein expression is often lost during progression to a more invasive phenotype. Interestingly, PDEF mRNA has been found to be retained or even overexpressed in the absence of protein; however, the mechanisms for this remain to be elucidated. This study identifies two microRNAs (miRNA) that directly act on and repress PDEF mRNA translation, leading to the loss of PDEF protein expression and the gain of phenotypes associated with invasive cells. In addition, we show that these miRNAs are elevated in human breast tumor samples. Together, these data describe a mechanism of regulation that explains, for the first time, the lack of correlation between PDEF mRNA and protein levels, providing insight into the underexplored role of posttranscriptional regulation and how this contributes to dysregulated protein expression in cancer. These observations have critical implications for therapeutically targeting miRNAs that contribute to cancer progression.

The positive effect of adenoma weight and oxyphil cell content on preoperative localization with 99mTc-sestamibi scanning for primary hyperparathyroidism

Background Although the sensitivity of sestamibi scanning (MIBI) is high in patients with solitary parathyroid adenomas, negative sestamibi scan results are inevitable. The exact mechanism of visualization of abnormal and hyperfunctioning parathyroid tissue is not yet clear. The aims of this clinical study were (1) to evaluate positive and negative sestamibi scan results with regard to adenoma weight and oxyphil cell content and (2) to compare the effects of adenoma weight and oxyphil cell content on the results of sestamibi scanning. Patients The patients were divided in 2 groups according to their sestamibi scan results. Group 1 consisted of 27 patients with positive sestamibi scan results, and group 2 consisted of 20 patients with negative sestamibi scan results. Parathyroid adenoma weight and oxyphil cell content were determined in all patients. Results The weight and oxyphil cell content of the parathyroid adenomas in the patients of group 1 were significantly higher than those in the patients of group 2 ( P = .001). An adenoma weight >600 mg and an oxyphil cell content >20% increased the rate of obtaining a positive sestamibi scan result 10- and 4-fold, respectively. Conclusions Both adenoma weight and oxyphil cell content were found to significantly correlate with positive sestamibi scan results. In patients with high-weight adenomas, adenoma weight was the most significant factor in obtaining positive MIBI scan results, whereas in patients with low adenoma weights, high oxyphil cell content was the most significant factor in obtaining positive MIBI scan results.

C-kit: Identification of co-regulated genes by gene expression profiling and clinical relevance of two breast cancer subtypes with stem cell like features

622 Background: Expression of the proto-oncogene c-kit has been found in malignant tissue including a subset of breast cancers. c-Kit is also expressed in normal breast tissue and several authors found a loss of c-kit expression in breast carcinoma suggesting it might be involved in the growth control of mammary epithelium. Until now, only a few markers were described to be co-regulated with c-kit. To elucidate the possible role of c-kit in malignant transformation, we analyzed gene expression data of breast cancer patients. Methods: Tumor tissue of n=171 breast cancer patients were analyzed by gene expression profiling using Affymetrix Hg U133 Arrays (22,500 genes) and bioinformatic analyses. Tumor samples with high stromal and low epithelial cell content by gene expression profiling were excluded for further analysis. Validation was performed with n=100 independent samples. Results: A total of 10.5% of the tumors showed strong c-kit expression (2.5 fold above median). A careful dissection of global expression data revealed strong correlations of c-kit with the expression of a large cluster of genes containing several for whom c-kit coexpression was already described (HER1, CK-5/-17, PDGFR) as well as several members of the wnt signalling pathway, providing a possible novel link to mammary epithelial differentiation. Analysis of n=171 breast cancer samples according to this gene set allows the identification of putative “stem cell like” tumors (SCL) characterized by expression of several known stem cell markers. Surprisingly, a tight link of ER status and proliferation is restricted only to these SCL tumors but lost among non-SCL tumors. The clinical implications of our findings will be presented. Conclusions: For the first time these data bring together the description of two breast cancer subtypes identified by gene expression profiling with the actual stem cell model of the development of breast cancer. No significant financial relationships to disclose.

Cytotoxic Markers and Frequency Predict Functional Capacity of Natural Killer Cells Infiltrating Renal Cell Carcinoma

Renal cell carcinoma harbors high numbers of infiltrating lymphocytes with apparent limited efficacy in tumor control. This study focused on the natural killer (NK) cells infiltrating renal cell carcinoma. Tumor-infiltrating lymphocytes (TIL) were isolated from renal cell carcinoma and analyzed for NK cell frequency and phenotype (n = 34). NK cells were enriched and tested for effector function. Two renal cell carcinoma subtypes were identified, one containing high (>20% of the lymphocyte population, n = 14), the other low (<20%, n = 20), NK cell numbers. NK cells of both groups were noncytolytic ex vivo but differed in CD16 and cytotoxic effector molecule expression as well as in their capacity to acquire cytotoxic activity: The majority of NK cells from tumors with high NK cell content (high NK-TIL) were CD16(bright), whereas few CD16bright NK cells were found in tumors with low NK cell frequencies (low NK-TIL). The CD16 dichotomy correlated with different capacities to develop cytotoxicity after short-term activation with interleukin-2 ex vivo: Low NK-TIL remained noncytolytic against K562 and unresponsive to signals via the activating receptor NKp46 despite expression of receptor and adaptor molecules. In contrast, high NK-TIL acquired cytotoxic function. As described for peripheral CD16bright NK cells, NK cells from high-NK tumors showed high per cell expression of granzyme A, granzyme B, and perforin. NK cells from low NK-TIL resembled CD16(neg/dim) peripheral NK cells with few cytotoxin+ cells and lower expression of perforin. The extent of NK cell infiltration and the expression of markers (CD16 and cytotoxins) predict the functional capacity of NK cells infiltrating renal cell carcinoma and can be used to characterize subgroups of renal cell carcinoma.

Cytologic findings of peripheral T-cell lymphoma (PTCL) with high epitheloid cell content (Lennert's lymphoma) in imprint smear. A case report

BackgroundLymphoepitheloid lymphoma is a T-cell lymphoma with peculiar histologic picture with massive proliferation of epitheloid cell clusters intermingled with many, mostly small-sized lymphoid cells. The cytomorphologic features in imprint of a case of lymphoepitheloid T-cell lymphoma is described together with diagnostic pitfalls.Case reportA 74 years old man presented with weight loss, anemia and fever. Physical examination showed bilateral cervical lymphadenopathy with hepatosplenomegaly. With the clinical impression of hypersplenic syndrome vs lymphoma, excisional biopsy of a lymph node was performed and both imprints and histologic sections made. Cytologic findings showed uniform isolated small lympocytes with closely intermingled scattered and aggregates of epitheloid cells. Histologic sections were diagnosed as lymphoepitheloid lymphoma (Lennert's lymphoma).ConclusionCytologic findings of this variant of lymphoma is distinctive enough for a correct initial suggestive diagnosis. However the presence of high content of epitheloid cell clusters can cause cytologic misinterpretation with other benign and malignant conditions.

Algal Polyunsaturated Fatty Acids: Food, Pheromones and Foul Odour

AbstractAlgal polyunsaturated fatty acids (PUFAs) are known to be high‐energy, often‐essential resources to freshwater aquatic food webs. On the other hand, high PUFA cell content in some algal taxa has been linked with the production of derivatives that may act as pheromones, allelogens or toxins. It has been known for some time that these compounds function in marine chemical ecology, but recent evidence indicates that they may play similar roles in freshwater ecosystems. This paper presents field and laboratory studies of planktonic and periphytic communities from freshwater systems, and shows that these communities are rich sources of certain PUFAs and derivatives which may function in both positive and negative foodweb interactions. This also has important implications for surface water quality, as these compounds are potent sources of rancid fishy odours.

Differences in the growth inhibition of cultured K-562 cells by selenium, mercury or cadmium in two tissue culture media (RPMI-1640, Ham's F-10).

Effects of some metals on the growth of cultured human erythroleukemia K-562 cells were investigated when grown in two different types of media based upon RPMI-1640 or Ham's F-10. The study on proliferation, using RPMI-1640 supplemented with sodium selenite, selenomethionine, mercuric chloride, methylmercuric chloride and cadmium nitrate showed no inhibition of growth at concentrations of 2.5, 25, 25, 2.5 and 25 microM, while at 75, 250, 50, 5 and 50 microM toxicity was apparent. Selenite at 5-50 microM and selenomethionine at 50-100 microM inhibited the growth. In Ham's F-10 supplemented with the same compounds no inhibition was found at concentrations of 5, 10, 25, 1 and 50 microM, while at 50, 100, 50, 5 and 75 microM toxic effects were noted. Selenite 10 microM and selenomethionine 25-50 microM inhibited the proliferation. Measurements of trace element levels in pellets of K-562 cells grown in RPMI-1640 or Ham's F-10 unveiled higher cell contents of cadmium and selenium in cells grown in RPMI-1640, being consistent with higher concentrations of these elements in that medium. Manganese and mercury concentrations were higher in cells grown in Ham's F-10 correlating with a higher medium concentration of these elements. The growth responses and cellular uptake differed between the metals and the selenocompounds and although extrapolating the results to humans is difficult the selenium exposures were in approximately the same order of magnitude as in human exposures. The compounds could be ranked according to decreasing toxicity as: methylmercuric chloride > mercuric chloride, cadmium nitrate, sodium selenite > selenomethionine.

Portal pressure in patients with exudative ascites in the course of acute hepatitis B

We describe three patients who developed ascites during the course of acute viral hepatitis B. Two of them had exudative ascites, with a high protein and cell content, and the other transudative ascites, with low protein and cell content. Both patients with exudative ascites had a benign clinical course, and their liver disease was milder than in the patient with transudative ascites, who had signs of severe liver failure and a submassive hepatic necrosis on liver biopsy. Moreover, the patient with transudative ascites had evidence of portal hypertension (as indicated by a hepatic vein pressure gradient of 12.5 mmHg, normal 1-6 mmHg), whereas patients with exudative ascites did not (hepatic vein pressure gradient of 5 and 5.5 mmHg, respectively). These data support our previous suggestion that "exudative" ascites during acute viral hepatitis B represents a self-limited immunopathetic sign that is not related to portal hypertension or severe hepatic disease.

Vegetation Community Selection by Ungulates on the Isle of Rhum. III. Determinants of Vegetation Community Selection

(1) This paper describes and discusses possible determinants of seasonal vegetation community selection of cattle, red deer, goats and ponies on the Isle of Rhum in the Inner Hebrides, Scotland. (2) The feeding strategies of each species are discussed with respect to a theoretical framework of constraints on diet selection in ungulates based on mouth size, body size and the digestive system within species of ruminant, their rumen morphology and digestive function. (3) Throughout the year the goats fed on vegetation communities containing high biomasses of live dwarf shrubs and forbs. The other species all fed predominantly on the grassland communities. (4) Cattle, having a large body size and rumen, a long passage rate of food material through their digestive tract and small incisor breadth: metabolic requirements ratios, fed on communities containing the highly digestible live mesotrophic graminoids and forbs when these were abundant and on communities containing live oligotrophic graminoids when the former declined in abundance. (5) Red deer stags and hinds, which are smaller and have larger incisor breadth: meta-bolic requirements ratios than cattle, selected vegetation communities containing live mesotrophic graminoids and forbs throughout the year. (6) Goats, having digestive systems adapted for fast passage rates, fed predominantly on communities containing live dwarf shrubs and forbs. Because of their high cell content concentration, this type of plant material will release most nutrients in the shortest time. (7) Ponies, being hindgut digesters, have relatively low digestive abilities and, as a result, high intake requirements. Consequently, they fed on communities with high biomasses of live mesotrophic graminoids and forbs when these were abundant and on communities with high biomasses of both live and dead mesotrophic graminoids and forbs when the biomass of the live component declined

Analysis of lymphocytes infiltrating the thyroid gland of Obese strain chickens.

Lymphocytes were isolated from the infiltrated thyroid glands of 2- to 5-wk-old Obese strain (OS) chickens with spontaneous autoimmune thyroiditis (SAT). Immunofluorescence analysis performed by using a panel of monoclonal and polyclonal antibodies revealed that 60% of thyroid infiltrating leukocytes (TIL) were mature T cells, a large portion of which seemed to be in an activated state bearing Ia-like antigens (10%) as well as a surface determinant associated with T cell activation (16%), i.e., possibly the receptor for interleukin 2 (IL 2). Furthermore, a relatively high plasma cell content (5%) was observed. TIL exhibited high proliferative responses to T cell mitogens (concanavalin A, phytohemagglutinin) and IL 2, but only weak responses to the B cell mitogen LPS from Salmonella typhimurium. When injected into newly hatched, MHC-identical, irradiated normal chickens, TIL induced both the production of autoantibodies and thyroid infiltration. Peripheral lymphocytes from spleen and blood and thymocytes from the same OS donors had no effect. Analysis of chemically (cyclophosphamide) bursectomized OS chickens suggested that an intact B cell system was not obligatory for the induction of SAT. TIL from these chickens consisted of 77% T cells and less than 1% B lymphocytes, yet were capable of inducing severe thyroid infiltration upon transfer into normal recipients. These findings emphasize the importance of the T cell system in the initiation of SAT.

AChE-positive fiber growth after hippocampal fimbria transection and peripheral nerve homogenate implantation

Gelfoam treated with peripheral nerve homogenate was implanted into a site of hippocampal fimbria transection in the adult rat to assess whether the homogenate might enhance growth of AChE-positive fibers into the lesion site and whether the fiber growth might be directed to the implants. Homogenate was prepared from intact peripheral nerve and in a few cases from degenerated nerve. Some implants were encased in Silastic. Homogenate was also injected into the denervated hippocampus. The major finding was that AChE-positive fiber growth was associated with regions of high astroglial cell content in preference to the relatively hypocellular implants. No clear differences in AChE fiber sprouting into the lesion site, fiber growth into implants, or hippocampal reinnervation were noted between homogenate and saline-treated animals.