Simultaneous Measurement of Proton and Lepton Kinematics in Quasielasticlike ν_{μ}-Hydrocarbon Interactions from 2 to 20 GeV

Neutrino charged-current quasielastic-like scattering, a reaction category extensively used in neutrino oscillation measurements, probes nuclear effects that govern neutrino-nucleus interactions. This Letter reports the first measurement of the triple-differential cross section for ν_{μ} quasielastic-like reactions using the hydrocarbon medium of the MINERvA detector exposed to a wideband beam spanning 2≤E_{ν}≤20  GeV. The measurement maps the correlations among transverse and longitudinal muon momenta and summed proton kinetic energies, and compares them to predictions from a state-of-art simulation. Discrepancies are observed that likely reflect shortfalls with modeling of pion and nucleon intranuclear scattering and/or spectator nucleon ejection from struck nuclei. The separate determination of leptonic and hadronic variables can inform experimental approaches to neutrino-energy estimation.

Monitoring a mouse colony for Helicobacter bilis using a Helicobacter-genus-specific nested PCR

Although Helicobacter infections of laboratory mice are usually subclinical, they may interfere with in vivo experiments and thus may lead to misinterpretation of data. As such, it is important to provide a means to unequivocally identify infections with murine Helicobacter spp. In the present study, a nested polymerase chain reaction (PCR) was established and shown to be 10 to 100 times more sensitive than the single-step PCR commonly used for routine diagnosis of Helicobacter spp. Experimental infection of Helicobacter-free mice demonstrated that faeces, caecum, colon and rectum but not liver are equally suitable for the detection of H. bilis. However, use of faecal pellets is advantageous since detection of H. bilis is possible one week after infection and analysis of faeces instead of tissues avoids euthanasia of animals. Furthermore, it generates representative data for all animals housed in the same cage and analysis can be repeatedly performed. Use of samples from breeding pairs but not offspring provides representative information about the Helicobacter status of a mouse colony. Both C3H/HeJ and C57BL/6 mice appear to be susceptible to H. bilis and persistent infection was observed during the 20-week experimental period. Analysis of pooled faecal pellets by nested PCR seems to be the most sensitive approach for H. bilis monitoring of the given breeding colony.

Fractal and Dendritic Growth of Surface Aggregates

The similarity of patterns formed in non-equilibrium growth processes in physics, chemistry and biology is conspicuous and many attempts have been made to discover common mechanisms underlying their growth. The central question in this context is what causes some patterns to be dendritic, as e.g. snowflakes, while others grow fractal (randomly ramified). Here we report a crossover from fractal to dendritic patterns for growth in two dimensions: the diffusion limited aggregation of Ag atoms on a Pt(111) surface as observed by means of variable temperature STM. The microscopic mechanism of dendritic growth can be analyzed for the present system. It originates from the anisotropy of the diffusion of adatoms at corner sites which is linked to the trigonal symmetry of the substrate. This corner diffusion is observed to be active as soon as islands form, therefore, the classical DLA clusters with the hit and stick mechanism do not form. The ideas on the mechanism for dendritic growth have been verified by kinetic Monte-Carlo simulations which are in excellent agreement with experiment.

Quality Assurance of an Organised Screening Programme for Breast Cancer in Denmark 1991-2008

Background: The capital city of Copenhagen, Denmark, has had an organised programme for screening with mammography since 1991. All women resident within the area of uptake and aged 50-69, representing around 45000 women, are invited biennially, unless they actively have asked not to be invited. We have evaluated the programme with regard to the European guidelines for quality assurance in breast cancer screening and diagnosis, to assess performance and impact.Methods: The target population was identified through the national population register, identifying all women meeting the inclusion criteria in terms of age and place of residence, migration and death. The mammography programme supplied data on all invited women, participation and screening test results. Oncological data was retrieved from the National Cancer Register and the Danish Breast Cancer Group. Data was linked using the Danish unique personal identity number.Results: In the first invitation round (1991-1992) the invasive cancer detection rate was 10/1000 and was by the 8th invitation round (2006-2007) 8/1000. The in situ detection rate has been 1/1000 throughout the period. The programme sensitivity is approximately 70%. The detection rate of small tumours (≤ 10mm) was, on average, 39% over the first 4 invitation rounds and 62% by the 8th invitation round. The benign to malign ratio changed from 1:1.6 to 1:11.4, from the first to the 8th invitation round. Recall rates at initial screen dropped from 7% to 4% in the period, and for subsequent screens from 4% to 2%. The false positive rate was 5.5% in the first invitation round and had by the 8th invitation round dropped to 1.3%, with a cumulative risk of 15% over 8 rounds. In the 8th invitation round, there was 82% coverage, a participation rate of 61% and a long term adherence of 50%.Conclusions: The results for the majority of indicators were well within the recommended levels. There had been a significant improvement in the benign to malign ratio, despite that the false positive rate at assessment had decreased. The detection of small tumours had also improved significantly. Participation rates were, however, lower than recommended.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4005.

The Human-Inducible Costimulator Ligand is Polymorphic

Inducible costimulator ligand (ICOSL) is a costimulatory molecule related to B7.1 (CD80) and B7.2 (CD86). B cells, monocytes, dendritic cells and endothelial cells express ICOSL. Inducible costimulator (ICOS) interacts with ICOSL, and this interaction leads to signals involved in isotype switching and the development of immunological memory. Hitherto, no polymorphisms of this gene have been described. The aim of this study was to reveal variation of the ICOSL gene in normal individuals. All eight exons, except exon 1, were sequenced with flanking introns in 10 healthy blood donors. Eight single nucleotide polymorphisms (SNPs) and two length polymorphisms were found. One of the SNPs was found in the coding regions of the gene. The base involved was located in exon 3 and caused a conservative amino acid change from valine (GTT) to isoleucine (ATT). Three individuals were heterozygous G/A for the exon polymorphism, while the remaining seven individuals were homozygous for the wildtype G/G. Exon 3 encodes the immunoglobulin variable (IgV)‐like domain of the molecule which is situated outside the cell. This means that the amino acid could be critical for the stability of the molecule or could constitute part of the binding site for ICOS. The results form the basis for further experiments to find possible associations of the alleles to diseases caused by immune dysregulation. Especially, the exon 3 variant is interesting and could play a role for the development of immunological diseases. Besides, it would be interesting to see whether both exon 3 alleles are expressed or only the wildtype allele is functional.

Normal ICOS, ICOSL and AID Alleles in Danish Patients with Common Variable Immunodeficiency

Common variable immunodeficiency, CVID, is a primary antibody deficiency characterized by decreased levels of serum immunoglobulin G (IgG), decreased IgA and/or IgM and recurrent infections. It is assumed to be heterogeneous group of disorders caused by different genetic defects. Some patients have decreased levels of class switched memory B cells and/or decreased levels of somatic hypermutation which points to defects in the germinal centre (GC) reactions as cause of the disease in these patients. The inducible costimulator, ICOS, and its' ligand, ICOSL, are both involved in and necessary for the GC reaction and so is activation-induced cytidine deaminase, AID. Therefore, we sequenced the ICOS, ICOSL and AID genes in a cohort of 34 Danish CVID patients. We found 13 new single nucleotide polymorphisms (SNP) in the intron regions of the ICOSL gene as well as one SNP in exon 3. However, none of these polymorphisms were associated with CVID. We did not find a previously reported CVID-causing ICOS gene deletion or any other unique mutations in the ICOS or AID genes.

Mouse antibody production test: can we do without it?

Introduction of microbiologically contaminated materials into mice can cause infections of the recipients and jeopardize experimental protocols. As such, the methods used to screen biological materials should be sensitive, reliable and suitable for routine diagnostic work. In this report, the sensitivity of the viral plaque assay, mouse antibody production test and polymerase chain reaction (PCR) for detection of MHV-A59 and MMVp, two of the most prevalent pathogenic viruses in experimental mouse facilities, was compared. Analysis of serial tenfold dilutions of virus stocks revealed that the sensitivity of the mouse antibody production test on day 28 (10(-10) dilution) was at least 10 times higher than that of the viral plaque assay (10(-9) dilution) and 10(4) times more than that of the RT-PCR (10(-6) dilution) for detection of MHV-A59. For detection of MMVp, the PCR (10(-10) dilution) proved to be 10(6) times more sensitive than the viral plaque assay (10(-4) dilution) and the mouse antibody production test on day 28 (10(-4) dilution) which were equally sensitive. Based on the present study, it was shown that the method for diagnosis of viruses in biological materials should be employed only after the sensitivity has been determined for the viruses of interest implying that the most sensitive method needs to be determined independently for each virus.

Receptor heteromerization in adenosine A2A receptor signaling: relevance for striatal function and Parkinson's disease

Recently evidence has been presented that adenosine A2A and dopamine D2 receptors form functional heteromeric receptor complexes as demonstrated in human neuroblastoma cells and mouse fibroblast Ltk- cells. These A2A/D2 heteromeric receptor complexes undergo coaggregation, cointernalization, and codesensitization on D2 or A2A receptor agonist treatments and especially after combined agonist treatment. It is hypothesized that the A2A/D2 receptor heteromer represents the molecular basis for the antagonistic A2A/D2 receptor interactions demonstrated at the biochemical and behavioral levels. Functional heteromeric complexes between A2A and metabotropic glutamate 5 receptors (mGluR5) have also recently been demonstrated in HEK-293 cells and rat striatal membrane preparations. The A2A/mGluR5 receptor heteromer may account for the synergism found after combined agonist treatments demonstrated in different in vitro and in vivo models. D2, A2A, and mGluR5 receptors are found together in the dendritic spines of the striatopallidal GABA neurons. Therefore, possible D2/A2A/mGluR5 multimeric receptor complexes and the receptor interactions within them may have a major role in controlling the dorsal and ventral striatopallidal GABA neurons involved in Parkinson's disease and in schizophrenia and drug addiction, respectively.

Delay of diagnosis in pancreatic cancer due to suspected symptomatic cholelithiasis

BACKGROUND

A single centre study was conducted to examine the frequency of cholecystectomies, both open and laparoscopic, up to 2 years prior to the diagnosis of pancreatic cancer. In particular, it was of interest to investigate whether there is a diagnostic delay in a significant number of pancreatic cancer patients and if these patients already have symptoms or findings at the time of cholecystectomy that might have been indicative of the underlying malignant disease.

METHODS

It is demonstrated that 17 out of 186 pancreatic cancer patients (9%) underwent a cholecystectomy within the 2 years prior to cancer diagnosis.

RESULTS

A significant number of these patients showed a considerable weight loss at the time of the cholecystectomy. It is hypothesized that symptoms which led to cholecystectomies in these patients were most likely related to the pancreatic cancer. Owing to the resulting delay of pancreatic cancer diagnosis the resection rate with curative intent decreases to 35% from 44% in the whole series.

CONCLUSION

Patients suffering from cholecystolithiasis and showing atypical symptoms or other notable findings such as considerable weight loss might be assessed in more detail pre- as well as postoperatively in order to minimize the diagnostic delay in pancreatic cancer and to avoid unnecessary operations.

Assessment of visual acuity in relation to central nervous system activation in children with mental retardation

Assessment of visual acuity was combined with observations of behavioral state indicating CNS activation in 24 individuals with mental retardation. Visual acuity was assessed by presentations of Teller Acuity Cards on two occasions. Behavioral state was classified along a scale with four categories during visual acuity testing. Results showed good test-retest reliability for the Teller Acuity Cards. Six participants had different behavioral state scores on the two test occasions, but displayed similar visual acuity on both tests. No participant rated as "drowsy" displayed responses on the acuity test. Results indicate that forced-choice preferential-looking technique can be used to test visual acuity in this population unless the participant is drowsy.

Rett syndrome and ageing: a case study

PURPOSE

This case study of an elderly women with Rett syndrome is used to consider whether observed changes may be related to physiological processes involved in ageing or environmental adaptations, which is important for delivery of rehabilitation.

METHOD

The life story of a woman with Rett syndrome who lived to the age of 60 is presented. It is based on medical records, older and more recent videotapes, and interviews with her sister and care staff.

RESULTS

After 21 years without walking, following intensive physiotherapy, she regained the ability to walk without support. She also showed improvement in hand use a few years before she died. During the early regression she appeared to lose social interest. The interest improved after some time, but she remained wary of people she did not know.

CONCLUSION

The walking and hand use indicate that these functions may have been present to a greater extent than assumed by people in the environment and that her poor function reflects dyspraxia and lack of opportunity and training rather than lack of ability. Although more studies of elderly women with Rett syndrome is needed to answer whether the observed changes were due to physiological processes involved in ageing or environmental adaptations, the present case story demonstrates that identification of females with Rett syndrome is important at all age levels.

[Chronic Monteggia injury in a child]

The case of a Monteggia fracture neglected from two years of age and seen at the age of fourteen, is described. A shortening of the affected ulna by three cm and a relative elongation of the radius was found. The function of the arm and elbow joint was remarkably unaffected with nearly full extension and flexion, supination and pronation. The carrying angle was ten degrees on both sides. Based on the literature, it is stressed that diagnosis and treatment of Monteggia lesions should be immediate. Complications in non-treated cases and at late treatment are many, and the results of such treatment dubious. It is thus of great importance that, when dealing with ulnar fracture a radiograph is also taken of the elbow joint to secure immediate diagnosis.

Hidden visual capabilities in mentally retarded subjects diagnosed as deaf-blind

The visual acuity of twelve multi-handicapped, mentally retarded subjects, diagnosed as deaf-blind, was measured on two occasions with the Teller Acuity Cards (TAC). Eight subjects scored above the criterion for legally blind and the results of six of these indicated various degrees of poor to approaching-normal eyesight. To evaluate high-level vision four subjects were tested with the Fagan Test, assessing visual recognition memory for faces subsequent to familiarization with the preferential looking technique. The results for three subjects showed evidence for perceptual recognition. It is concluded that TAC combined with the Fagan Test may detect perceptual capacities unnoticed by clinical observation.

Factors influencing the policy responses of host governments to mass refugee influxes

"The policy responses of asylum governments to mass influxes of refugees have varied considerably. Focusing on less developed countries, this article explores why some host governments respond in relatively generous ways, while other governments act more restrictively. The policy alternatives available to receiving governments are classified, and a set of factors influencing refugee policy formation is explored. These factors include: the costs and benefits of accepting international assistance, relations with the sending country, political calculations about the local community's absorption capacity, and national security considerations."

Adhesion receptors on bone marrow stromal cells: in vivo expression of vascular cell adhesion molecule-1 by reticular cells and sinusoidal endothelium in normal and gamma-irradiated mice

Cell adhesion molecules (CAMs) play a key role in interactions between stromal and hematopoietic cells in bone marrow (BM) and in cell traffic through vascular endothelium. To examine the identity of CAMs involved in these processes in mouse BM, we have investigated the in vivo expression of vascular cell adhesion molecule-1 (VCAM-1) and its counter-receptor, very late antigen-4 (VLA-4). Radioiodinated monoclonal antibodies (MoAbs) detecting VLA-4 and VCAM-1 were injected intravenously. Antibody binding was detected in BM by light and electron microscope radioautography. VCAM-1 labeling was restricted to stromal reticular cells and endothelial cells lining BM sinusoids. VCAM-1+ reticular cells formed patchy concentrations, especially in subosteal regions, associated with lymphoid, granulocytic, and erythroid cells. After gamma-irradiation to deplete hematopoietic cells, reticular cells and endothelial cells all showed VCAM-1 labeling in apparently increased intensity. VLA-4 labeling was shown by undifferentiated blast cells and lymphohematopoietic cells both in BM cell suspensions and in vivo, especially at reticular cell contact points. The results demonstrate that VCAM-1 is expressed in vivo by certain BM reticular cells, suggesting that the molecule mediates adhesion to multiple lineages of lymphohematopoietic cells. The finding that VCAM-1 is also expressed constitutively by BM sinusoidal endothelium, unlike its inductive expression by endothelia elsewhere, suggests that VCAM-1 and VLA-4 may be involved in regulating the normal cell traffic between BM and the blood stream.

Federal block grants and state spending: the Alcohol, Drug Abuse, and Mental Health block grant and state agency behavior

With renewed interest in block grants as a way to channel federal funds to states, several questions arise about the effect of block grants on state spending. A central question about the block grant form of intergovernmental aid is whether states spend the funds on the intended services or use budgetary strategies to appear to be in compliance with maintenance-of-effort provisions but then reallocate block grant funds from the targeted program. We studied the effect of the Alcohol, Drug Abuse and Mental Health block grant program on state substance abuse expenditures by analyzing spending data from the fifty states between fiscal years 1987 and 1992. Our findings suggest that this block grant has stimulated state spending, but this effect may be relevant only since 1990, and differs among states.

Preferential looking: a sudden shift in visual fixation pattern at 32 months of age

Observations of eye movements of young children in a modified preferential looking task suggest a change in the visual looking pattern taking place during a very brief time between 32 and 33 months of age. In the younger children, a grating stimulus elicited eye movements towards the target followed by a few seconds of focused attention; in the older children a visual avoidance behavior was observed where subjects looked consistently in the opposite direction of the target. An analysis of video recordings suggests that this avoidance pattern was a composite of a very brief initial target-directed eye movement which was quickly arrested, and followed by eye movements in the opposite direction, initiating a search of the visual scene.

Apoptosis and macrophage-mediated cell deletion in the regulation of B lymphopoiesis in mouse bone marrow

Studies of cell population dynamics and microenvironmental organization of B lymphopoiesis in the bone marrow of normal mice and in various genetically modified states have shown that cell loss, involving processes of apoptosis and macrophage-mediated cell deletion, is a prominent feature of the primary genesis of B lymphocytes. Balanced against the influence of proliferative stimulants, the programmed death of precursor B cells provides a quantitative control, determining the magnitude of the final output of functional B lymphocytes to the peripheral immune system. The cell loss mechanisms can be readily set in motion by external or systemic influences, making the B-cell output particularly vulnerable to suppression by ionizing irradiation, stress or other systemic mediators. In addition, however, cell loss exerts an important quality control in the formation of the primary B-cell repertoire. The combination of apoptosis and macrophage-mediated deletion, acting at successive stages of B-cell differentiation, efficiently eliminates many precursors having non-productive Ig gene rearrangements, cell cycle dysregulations, and certain autoreactive Ig specificities. Outstanding areas of further work abound. Important questions concern the nature of mechanisms which underlie the processes of B-cell apoptosis and macrophage deletion in bone marrow, the microenvironmental signals involved in B-cell life or death decisions and genetic factors which may override these B-cell culling mechanisms. The answers will be relevant to problems of autoimmune disease, humoral immunodeficiency and B-cell neoplasia.

[Pneumonia among patients admitted to intensive care units. An epidemiological multicenter study of APACHE II score, incidence and course]

Pneumonia in patients in intensive care units (ICU) is associated with several diagnostic difficulties and high mortality. This study was conducted to describe the diagnostic procedures and clinical characteristics of the pneumonic and critically ill patient in relation to APACHE II score. The material consisted of 193 patients admitted to seven Danish ICUs and is also included in a European epidemiologic survey (EURO.NIS). Twenty-eight (14.5%) developed pneumonia and 18 (9.3%) of these were nosocomial (> 48h after admission). Patients with pneumonia had a significantly higher APACHE II score, duration of stay and mortality. The techniques used to diagnose pneumonia were mainly conventional and did not or only seldom include protected brush, bronchoalveolar lavage or pulmonary biosy. The predominant pathogens isolated in tracheal aspirate were Gram-negative bacilli (50%). The APACHE II scoring system was found to stratify patients with respect to mortality, duration of stay and pneumonia diagnosed in ICU.

Immunohistochemical detection of metallothionein in primary breast carcinomas and their axillary lymph node metastases

Metallothioneins (MTs) are low-molecular-weight proteins with specific binding for group II metal ions. MTs are involved in the detoxification of metals, but can also play a role in protection of the cell against certain anticancer agents and from damage of irradiation. High expression of MTs in primary breast carcinomas has been found to be associated with poorer prognosis. Expression of MT (MT) was examined immunohistochemically in 160 breast carcinomas and their concomitant lymph node metastases. The immunoreactivity appeared to be independent of the length of fixation when the section was microwaved before incubation with the primary antibody, a monoclonal antibody E-9. The findings were correlated with various histopathological factors, disease-free survival and over-all survival. Patients were divided into two groups, those with MT over-expression (above 10% of positive tumour cells), and those with low MT expression (below 10% positive). MT over-expression was found to be correlated with postmenopausal status and inversely with positive progesterone receptor status (PgR). MT over-expression showed statistically significant correlation with poor over-all survival. No differences in survival were seen between pre- and postmenopausal patients. PgR was in univariate analysis a poor prognostic parameter. In one fourth of the patients, the lymph node metastases showed increased MT expression compared with the primary tumour. These patients had a poorer, but not statistically significant different survival. MT expression was not correlated to chemo- or radiation therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Electroacupuncture in anaesthesia for hysterectomy

We have studied the effects of electroacupuncture at classical acupuncture points, applied before and during surgery in patients undergoing hysterectomy, on postoperative pain and metabolic stress responses in a prospective, randomized and patient-blinded manner. Fifty otherwise healthy women were allocated randomly to receive or not receive electroacupuncture. Electroacupuncture was begun 20 min before skin incision and continued to the end of surgery. All patients received similar general anaesthesia and all received patient-controlled analgesia (PCA) after operation. Postoperative pain in the two groups was evaluated by recording analgesic requirements by PCA and by pain-rating performed by patients and nursing staff. There were no significant differences between the two groups in postoperative analgesic requirements, pain-rating or metabolic stress responses.

Cell populations during tumorigenesis in Eu-myc transgenic mice

Transgenic mice bearing a c-myc oncogene under control of the immunoglobulin heavy chain (Igh) enhancer (Eu-myc mice) (1, reviewed in 2) undergo a reproducible series of developmental stages and die from malignancies of the B lymphocyte lineage. To investigate the cellular events underlying tumorigenesis in this model, we quantified B lymphoid subpopulations and turnover at various stages of this process. An early stage was characterized by the presence in the blood of many large proliferating B lineage cells marked by surface antigen phenotype IgM+l-, B220low, CD5-, Mac-1low. During a prolonged intermediate 'remission' phase of different duration in each mouse, B lymphocytes in the periphery were non-proliferative, few, and of conventional phenotype (IgM+, B220+, CD5-, Mac-1-), while subsets of precursor B cells were both numerous and highly proliferative in the bone marrow. In the final stage of tumorigenesis, large proliferating cells similar in phenotype to those of the early period reappeared and increased rapidly in numbers. This B cell tumorigenic progression occurred independently of interactions with T lymphocytes. Evidence of massive cell death in the bone marrow during the intermediate phase, plus molecular characterization of the final tumors, suggested that the end of the peripheral 'remission' period and entry into the terminal stage of tumorigenesis may be due to a clone of cells acquiring the ability to circumvent normal processes of cell death and elimination that usually regulate the egress of B cells from the bone marrow to the periphery.

Highly restricted expression of a stromal cell determinant in mouse bone marrow in vivo

B lymphocyte precursor cells in mouse bone marrow develop in close association with stromal cells which provide essential growth signals. To identify molecules that may normally play a role in this interaction we have examined the in vivo binding of a new monoclonal antibody (mAb) (KMI6) that recognizes a determinant on a bone marrow stromal cell line (BMS2) in vitro. Flow cytometric and radioautographic evaluations revealed that the antigen recognized by KMI6 is represented on the surface of an extremely small number of cells in bone marrow cell suspensions from adult mice. An apparent molecular mass of 110 kD was obtained by surface labeling of a stromal cell clone and immunoprecipitation. Purified mAb KMI6 labeled with 125I was then given intravenously to young C3H/HeJ mice. Unbound mAb was washed out by cardiac perfusion and femoral bone marrow was examined by light and electron microscope radioautography. KMI6 labeling was heavy on the plasma membrane of many stromal cells, especially those located towards the outer subosteal region. The KMI6-labeled stromal cells were usually associated with cells of lymphoid morphology which they often completely surrounded. The labeling was restricted to areas of stromal cell plasma membranes in contact with lymphoid cells. The lymphoid cells themselves, as well as macrophages and other hemopoietic cells, failed to bind mAb KMI6 significantly. Stromal cells in bone marrow depleted of hemopoietic cells by gamma-irradiation (9,5 Gy) bound mAb KMI6 at reduced intensity. The results demonstrate that the KMI6 determinant, a 110-kD protein, is expressed on bone marrow stromal cells in vivo. Its restriction to areas of interaction with lymphoid cells suggests a role in forming microenvironmental niches of B lymphopoiesis. The surface membrane of individual stromal cells may thus be functionally polarized towards interacting B cell precursors and other hemopoietic cells.

Dynamics and localization of early B-lymphocyte precursor cells (pro-B cells) in the bone marrow of scid mice

Mice homozygous for the scid (severe combined immunodeficiency) mutation are generally unable to produce B lymphocytes, a condition attributed to defective rearrangement of immunoglobulin genes in precursor B cells. Some early B-lineage cells are present in the bone marrow (BM), however. In scid mice, we defined three subsets of early progenitor B cells lacking mu heavy chains (pro-B cells) based on the expression of terminal deoxynucleotidyl transferase (TdT) and B220 glycoprotein: (a) early pro-B cells (TdT+B220-), (b) intermediate pro-B cells (TdT+B220+), and (c) late pro-B cells (TdT-B220+). Double immunofluorescence labeling of BM cell suspensions has shown normal numbers of early and intermediate pro-B cells, substantially reduced numbers of late pro-B cells, and an absence of pre-B cells and B cells. Early and intermediate pro-B cells accumulated in metaphase in near-normal numbers after intraperitoneal (IP) vincristine administration. B220+ pro-B cells have been localized in BM sections by the binding of intravenously (IV) administered 125I monoclonal antibody (MoAb) 14.8, detected by light and electron microscope radioautography. Many B220+ cells were located peripherally in the bone-lining cell layers associated with stromal reticular cells. More centrally located B220+ cells were frequently associated with macrophages containing prominent cytoplasmic inclusions. Occasional B220+ cells were present in venous sinusoids. These results demonstrate that many pro-B cells in scid mice occupy microenvironments in the BM near the surrounding bone. The pro-B cells maintain normal rates of production during stages of presumptive mu heavy-chain gene rearrangement, apparently unaffected by the absence of a mature B cell pool. Nearly all defective cells then abort at the late pro-B cell stage and are deleted, apparently by macrophages. The findings contribute to models of in vivo differentiation, regulation, localization, and selection of early B-lineage cells in the BM.

Acute and habitual caffeine ingestion and metabolic responses to steady-state exercise

This study compared the exercise catecholamine and metabolic responses to a caffeine challenge in trained subjects before and after a 6-wk period of increased caffeine ingestion. Trained subjects (n = 6) were challenged with 500 mg of caffeine followed by prolonged exercise before and after 6 wk of increased caffeine ingestion (500 mg ingested before each daily run). A control group (n = 6) of trained subjects followed the same protocol except for caffeine ingestion. Acute caffeine ingestion resulted in increased plasma epinephrine and decreased respiratory exchange ratio (RER) during exercise. After 6 wk of caffeine supplementation, the epinephrine response to exercise or caffeine plus exercise was decreased, although the latter still resulted in a lower RER value compared with exercise without caffeine ingestion. Activity of key metabolic enzymes (hexokinase, citrate synthase, phosphorylase, and 3-hydroxyacyl-coenzyme A dehydrogenase) from biopsies of the gastrocnemius showed no response to 6 wk of this increased adrenergic receptor stimulation and, on the basis of the lower RER, enhanced fat metabolism. This study suggests that caffeine ingestion by trained subjects causes increases in plasma epinephrine and reduces the RER during exercise. However, habitual stimulation results in a general dampening of the epinephrine response to caffeine or exercise. There was no indication that increased adrenergic stimulation and fat oxidation caused any adaptation in the activity of metabolic enzymes.