The impact of varying degrees of iron nutriture on several functional consequences of iron deficiency in rats

The impact of varying severities of iron-deficiency anemia on fasting blood glucose, plasma triiodothyronine, heart norepinephrine concentrations and resting oxygen consumption were evaluated. Male weanling Sprague-Dawley rats were assigned to one of six dietary groups (4, 6, 11, 16, 23 or 40 mg Fe/kg diet) for 6 wk. Hemoglobin, liver iron and transferrin saturation were significantly lower in the 4 and 6 mg Fe/kg diet groups relative to the other groups and were indicative of anemia, low tissue iron stores and impaired erythropoiesis. Fasting blood glucose and heart norepinephrine concentrations were significantly higher and lower, respectively, in the 4 and 6 mg Fe/kg diet groups than the three highest dietary Fe groups. Although fasting blood glucose was significantly inversely correlated (r = -0.89, P = 0.0001) with hemoglobin concentration; a significant quadratic relationship (R 2 = 0.70, P = 0.0001) existed between hemoglobin and heart norepinephrine concentration. Differences in plasma triiodothyronine concentrations and resting oxygen consumption were not significant among the groups. Thus, base on hemoglobin concentration as an index of the severity of iron deficiency, these findings demonstrate that certain physiological manifestations of iron deficiency occur at even moderate-to-mild degrees of anemia.

Relationship between pyridinoline concentration and thermal stability of bovine intramuscular collagen

Semimembranosus muscle samples were obtained from 49 Holstein beef animals representing different USDA maturities. Intramuscular collagen (IMC) was isolated in the frozen state and evaluated for heat-labile collagen solubility (% Sol), thermal shrinkage temperature (Ts), enthalpy (Hs) changes, and mature crosslink (pyridinoline) content. These measures were obtained to elucidate a relationship between pyridinoline content of IMC and beef maturity level and to relate IMC thermal stability (% Sol, Ts, and Hs) to pyridinoline content. With increasing maturity, % Sol decreased (P less than .01) and Ts increased (P less than .01), whereas Hs showed no change (P greater than .05). Thus, IMC melted at increasing temperatures, but the amount of energy required to induce this endothermic change remained constant throughout maturation. The pyridinoline content of IMC increased (P less than .01) linearly with maturity, indicating that this heat-stable, mature crosslink enhances thermal stability of IMC as beef muscle matures. Significant correlations between pyridinoline content and maturity (r = .56; P less than .001) and Ts (r = .34; P less than .05) support this contention.

PIS and DRGs: coding inaccuracies and their consequences for resource management

Accurate information is important for the successful implementation of the Resource Management Initiative and the NHS White Paper. A review of 153 joint replacements performed in a three-month period in Leicester showed that 24 per cent of 139 procedures for which medical notes were available had been given incorrect Diagnosis-Related Groupings (DRGs). Of these, 64 per cent could be ascribed to errors in allocating OPCS-3 codes and 36 per cent to errors in converting OPCS-3 codes to DRGs by computer. It is of concern that inaccurate information may in future be used to allocate resources. The resource implications of assiduous quality control of recording, coding and computing is pointed out, and it is suggested that improved classification systems should be assessed for use in the NHS.

The role of interleukin 4 in specific antibody responses by human B cells

This study was designed to investigate the requirement for interleukin 4 (IL-4) in specific antibody responses by human lymphocytes. Addition of IL-4 to antigen (influenza virus)-stimulated cultures of tonsillar mononuclear cells was found to suppress specific antibody production significantly at doses as low as 10 units/ml. Specific immunoglobulin (IgG), IgA, and IgM antibodies were all equally inhibited by IL-4. Inhibition of the antibody response with IL-4 was completely abrogated by an IL-4 blocking antibody showing that the effect was specific for IL-4. It was also found that anti-IL-4 did not inhibit specific antibody production, showing that IL-4 was not required for responses to antigen. In contrast, significant inhibition was obtained with anti-Tac, indicating an important role for IL-2. In the absence of T helper cells antibody responses to influenza virus were completely restored with T cell replacing factor [TRF; IL-2 or low-molecular-weight B cell growth factor (BCGFlow)], but not with IL-4. In fact, IL-4 significantly suppressed the antibody response obtained when either IL-2 or BCGFlow was used as a TRF. Addition of IL-4 at different times after in vitro stimulation with antigen and IL-2 showed that the inhibitory activity of IL-4 was maximal during the first 3 days of culture and was lost by day 4. IL-4 therefore seems to inhibit an early activation event (possibly dependent on IL-2 or BCGFlow), or B cell proliferation essential for specific responses to antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute upper respiratory tract viral illness and influenza immunization in homes for the elderly

Occupants of 482 long-stay and 33 short-stay beds in 11 Leicester City Council homes for the elderly were studied during a 30-week period from September 1988 to March 1989 to determine the incidence, aetiology, morbidity, and mortality of acute upper respiratory tract viral infections and the use of influenza vaccine. Influenza immunization rates by home ranged from 15.4 to 90% (mean 45%). There were no differences in the distribution of medical conditions by home. The highest immunization rates were seen in people with chest disease (77%), heart disease (60%), diabetes (56%), and those with three medical conditions (75%). There was an average of 0.7 upper respiratory episodes per bed per annum with a mortality of 3.4% (6/179). Half of all episodes were seen by a general medical practitioner and 81 of 90 (90%) referrals were prescribed antibiotics costing approximately 7.50 pounds per patient. Lower respiratory tract complications developed during 45 (25%) of 179 episodes including 3 of 12 coronavirus infections, 3 of 9 respiratory syncytial virus infections, 2 of 4 adenovirus infections, 1 of 11 rhinovirus infections, but none of 5 influenza infections. Respiratory infections were caused mostly by pathogens other than influenza virus during the influenza period documented nationally. This highlights the role of coronaviruses, respiratory syncytial virus, and unidentified agents in the elderly, and questions the assumptions made in American estimates on the impact of influenza and the value of influenza vaccines.

Regional changes in creatine kinase and myocyte size in hypertensive and nonhypertensive cardiac hypertrophy

Several intracellular enzymes have been shown to have altered total activity or isoenzyme composition in cardiac hypertrophy. This study tests the hypothesis that the accumulation of the fetal-type (BB + MB) creatine kinase (CK) isoenzymes in hypertrophied adult myocardium is related to an increase in blood pressure. Consideration was made for the location, size, and hemodynamic load of the myocytes. By using the two-kidney, one-clip (2K1C) rat model of renal hypertension with and without hydralazine treatment, CK (total and isoenzyme), lactate dehydrogenase, and citrate synthase activities and myocyte size were measured. An increased heart weight/body weight ratio occurred in both untreated 2K1C rats (4.15 +/- 0.09) and hydralazine-treated 2K1C rats (4.12 +/- 0.13) as compared with control rats (3.25 +/- 0.10). Blood pressure was high only in untreated 2K1C rats (196 +/- 9 mm Hg), as compared with hydralazine-treated 2K1C rats (142 +/- 6 mm Hg) and control rats (135 +/- 3 mm Hg). Myocytes were isolated from five ventricular regions: left ventricular epicardial and endocardial free wall, left and right halves of the interventricular septum, and right ventricular free wall. Regional differences in normal and hypertrophied myocardium were demonstrated for morphological and biochemical parameters, with the greatest changes occurring in left ventricular endocardium. The shift in CK isoenzyme expression toward accumulating more BB + MB was greater in "hypertensive hypertrophy" (untreated 2K1C rats) than in "nonhypertensive hypertrophy" (hydralazine-treated 2K1C rats). Calculations incorporating isolated myocyte volume showed that the cellular content of total CK remained the same during the hypertrophic process, accounting for a decrease in the tissue activity. Measurement of lactate dehydrogenase and citrate synthase activities suggests that hypertrophied myocardium has relatively higher glycolytic capacity and that this effect is exacerbated in the presence of high blood pressure. We conclude that increased blood pressure is more closely linked to the fetal CK isoenzyme shift than is hypertrophy alone.

Listerial myocarditis in cardiac transplantation

Clinical signs of heart failure developed in two cardiac transplant recipients and were interpreted initially as graft rejection. Morphologic examination of explanted hearts revealed myocarditis with abscess formation and necrosis consistent with a bacterial process; Listeria monocytogenes was isolated from myocardial tissue in the first case and from blood in both. The first patient also developed signs of meningoencephalitis, but the second had no signs of infection outside the heart. Antimicrobial therapy and retransplantation were successful in eradicating listeriosis. The differential diagnosis of heart failure in cardiac transplant recipients includes infectious myocarditis due to L. monocytogenes.

The structure and associations of the double S layer on the cell wall of Aquaspirillum sinuosum

Aquaspirillum sinuosum cell walls bear two paracrystalline, proteinaceous surface layers (S layers). Each shows a different symmetry: the inner layer is closely apposed to the outer membrane and is a tetragonal array (90 degrees axes; 5-nm units; repeat frequency 8 nm); the outer layer is a hexagonal array on the external surface (14-nm units; repeat frequency 18 nm) and, although the units have a six-pointed stellate form, the linkage between units is not resolved. The outer layer consists of a major 130-kDa protein and a 180-kDa minor component; these co-extract, co-assemble, and are inseparable by hydroxylapatite chromatography or by recrystallization. The solubilizing effects of reagents suggest stabilization by hydrogen bonding and Ca2+. The two outer layer proteins are serologically related and show partial identity by peptide mapping. Periodic acid--Schiff staining of the 180-kDa band suggests that this may be a glycosylated form of the 130-kDa component. The inner layer components form a doublet of 75- and 80-kDa polypeptides with extreme resistance to extraction. Close apposition to the outer membrane, resistance to chaotropes, aqueous insolubility, and behaviour in charge-shift electrophoresis suggest hydrophobic interaction between subunits and an integral association with the outer membrane.

Human T cell-replacing factor(s): a comparison of recombinant and purified human B cell growth and differentiation factors

Conditioned medium from phytohemagglutinin-activated T cells contains T cell-replacing factor(s) (TRF) able to restore specific antibody responses by human blood or tonsillar B cells which have been thoroughly depleted of T cells. Of twelve recombinant cytokines tested as possible candidates for TRF in conditioned media, namely human recombinant interleukin (hrIL) 1 alpha and beta, hrIL2, hrIL3, hrIL4, hrIL5, hrIL6, hrIFN-alpha and -gamma, hr granulocyte macrophage colony-stimulating factor (hrGM-CSF) and tumor necrosis factor (hr TNF)-alpha and -beta only IL2 was found to have TRF activity. In addition, a semi-purified low molecular weight B cell growth factor (BCGFlow) also had TRF activity. As the commercially available BCGFlow is known to contain low concentrations of IL2, IFN-gamma, TNF and GM-CSF as impurities, it was important to exclude these as being responsible for the TRF activity. At the concentrations present in BCGFlow (less than 0.2 U/ml), IL2 was not active in the TRF assay. In contrast, a combination of IL2 (0.2 U/ml), IFN-gamma (50 U/ml), TNF-alpha (50 U/ml) and TNF-beta (100 U/ml) did have TRF activity suggesting that B cells could be made to respond to low doses of IL2 by the presence of other cytokines. Although this finding raises important questions about the nature of TRF in conditioned medium, the TRF activity of BCGFlow was unlikely to be due to such a synergistic combination of cytokines for the following reasons. First, in several experiments, responses were obtained with BCGFlow, but not with IL2 or combinations of IL2 with IFN and TNF. Second, antibody to IL2 was found to inhibit the TRF activity of IL2 but not of BCGFlow. Taken together these findings show that two distinct cytokines (IL2 and BCGFlow) are TRF for human B cells. However, some combinations of cytokines can also have TRF activity underlining the complexities which can arise from working with semi-purified rather than recombinant factors.

Clinically significant valvular heart disease in systemic lupus erythematosus

PURPOSE

Clinically significant valvular heart disease due to systemic lupus erythematosus (SLE) has generally been considered rare, and Libman-Sacks endocarditis has been thought to be predominantly an autopsy finding. With the declining prevalence of rheumatic heart disease, however, the spectrum of valvular heart disease is changing. We retrospectively analyzed our experience with SLE between 1975 and 1987 for the presence of hemodynamically significant valvular heart disease.

PATIENTS AND METHODS

An existing data base of 421 patients with SLE was selected for review. Patients were selected for inclusion in the study if they met four or more of the criteria of the American Rheumatism Association for SLE, they had clinically significant valvular heart disease, and tissue from the involved valve was available for review. The etiology of the valve lesion was determined by assessment of the clinical history, chart review, gross morphology, and valve histology.

RESULTS

Of 14 cases with pathologic material available for review, six had anatomic features of SLE valvular heart disease such as verrucous vegetations or valvulitis with necrosis and vasculitis. Two of these patients underwent successful valve replacements and four died from complications of their valve disease.

CONCLUSION

We suggest that significant morbidity and mortality may result from SLE valvular heart disease in about 1 to 2 percent of SLE patients and that the pathogenetic mechanisms underlying valve dysfunction in SLE patients are multifactorial.

Regional myocyte size in two-kidney, one clip renal hypertension

Regional variations in the size and shape of isolated myocytes were studied using the two-kidney, one clip (2K1C) renal model of hypertension. Weanling male Sprague-Dawley rats (50 to 75 g) were anesthetized by ketamine (100 mg/kg) during renal artery clipping (0.2 mm internal diameter silver clip) and were then allowed to grow for 6 to 8 weeks, when the blood pressure had stabilized at 180 mmHg. Hearts were removed, weighed and then were perfused with a calcium-free Joklik medium containing collagenase. Isolated myocytes were collected from five regions and fixed in isoosmolar glutaraldehyde: right ventricular free wall (RVFW), right and left halves of the interventricular septum (RIVS, LIVS), and epicardial and endocardial halves of the left ventricular free wall (LEPI, LENDO). Myocyte volume was measured by Coulter Counter. Myocyte length was measured by sonic digitizer. Cross-sectional area was calculated from myocyte volume and length. Tailcuff systolic pressure and heart weight were significantly increased in 2K1C rats as compared to control. Body weights were not different. Cell volume was significantly increased in RIVS, LIVS, LEPI, and LENDO, but not in RVFW. Cell length was not significantly increased in any region. Thus, the 2K1C model showed a predominant left ventricular hypertrophy in which the right half of the septum acted in concert with the left ventricle. The shape of the hypertrophied myocytes, having an increase in volume due to an increase in cross-sectional area but not length, was most consistent with a pressure-induced form of cardiac hypertrophy.

The marmoset B-lymphoblastoid cell line (B95-8) produces and responds to B-cell growth and differentiation factors: role of shed CD23 (sCD23)

The EBV-producing marmoset B-cell line (B95-8), commonly used as a source of EBV for stimulation and transformation of human B cells, was shown to proliferate in response to supernatants containing human B-cell growth factors (BCGF) derived from PHA-activated T cells or the KG-la cell line, and to a commercial low molecular weight BCGF (BCGFlow), but not to recombinant human IL-4 (rhIL-4). In this respect, B95-8 responded in much the same way as human EBV-transformed lymphoblastoid cell lines (LCL). In contrast, B95-8 did not secrete immunoglobulin in response to B-cell differentiation factor (BCDF) containing supernatants from the KG-la cell line, nor to BCGFlow, or IL-6 obtained from the T24 bladder carcinoma cell line, whereas significant responses were obtained with human EBV-transformed LCL. Both B95-8 and control EBV-transformed human LCL secreted BCGF and BCDF detected with the indicator B-cell lines CESS, L4, and HFB1, but only the human LCL secreted BCGF detectable in co-stimulation assays with TPA-activated tonsillar B cells. Unlike EBV-transformed LCL, B95-8 did not express detectable surface CD23, and did not release into the culture medium soluble CD23 (sCD23) recognized by an EIA for the human molecule. Although not releasing detectable sCD23, B95-8 cells did proliferate in response to purified human sCD23, and were found to be 1000 times more sensitive in this assay than EBV-transformed LCL. This may provide a basis for a sensitive bioassay for sCD23. Unlike EBV-transformed LCL, it seems that in vitro proliferation of B95-8 may involve an autocrine loop which does not depend on CD23.

Interleukin 2 and low molecular weight B cell growth factor are T cell-replacing factors for different subpopulations of human B cells

Both recombinant human interleukin 2 (rhIL 2) and low molecular weight B cell growth factor (BCGFlow) were shown to be T cell-replacing factors (TRF) in specific antibody responses to influenza virus by human blood and tonsillar B cells. When B cells were separated into high and low-density populations on Percoll gradients at 1.074 kg/l, IL 2 was found to act as a TRF only on the low-density B cells, whereas BCGFlow was a TRF for high-density B cells with a lesser effect on low-density B cells. Both populations of B cells responded well in the presence of T cells. The high-density B cells could not be activated to respond to IL 2 by either IL 1, rhIL 4 or by a CD22 monoclonal antibody known to enhance B cell activation. In contrast, a 24-h preincubation with T cells and antigen appeared to prime high-density B cells to respond to IL 2. These results show that high-density B cells can in fact respond to TRF, and that IL 2 and BCGFlow act on different populations of B cells which may be defined by prior exposure to T cells.

7-Aminoquinolines. A novel class of agents active against herpesviruses

A series of 7-aminoquinoline derivatives was synthesized and evaluated for their capacity to produce cytotoxicity in KB cells and to inhibit the replication of herpes simplex virus (HSV) type 1. All compounds tested inhibited the replication of HSV-1 with 50% inhibitory concentrations in the range of 2-50 micrograms/mL. The antiviral activity of many compounds, however, was separated from cytotoxicity to replicating uninfected cells by only two- to fivefold higher than those required for antiviral activity. Nonetheless, six compounds (10, 28, 29, 32, 34, and 36) were identified in which the separation was greater than fivefold. All compounds examined were more potent inhibitors of viral DNA synthesis than the cellular DNA synthesis.

Response of LFA-1-deficient B cells to interleukin 4 (BSF-1) and low molecular weight B cell growth factor (BCGFlow)

T cell-depleted B cells from a patient with LFA-1 deficiency were tested in costimulation assays for responsiveness to recombinant human IL4 (BSF-1) and purified low molecular weight B cell growth factor (BCGFlow). In both cases the response of LFA-1-deficient B cells was comparable with normal controls. Monoclonal antibodies to LFA-1 alpha (CD11a) and beta (CD18) chains were unable to mimic the action of IL4 on normal B cells in costimulation assays with anti-IgM, and did not inhibit normal B cell proliferation in response to IL4 and anti-IgM. Epstein-Barr virus-transformed lymphoblastoid B cell lines (LCL) from normal and LFA-1-deficient donors both responded in proliferation assays to BCGFlow but not IL4. Similarly, both normal and LFA-1-deficient LCL increased IgM secretion in response to BCDF, BCGFlow and, interestingly, IL4. The normal LCL also increased IgG secretion in response to these factors, but no IgG was detected in supernatants from the LFA-1-deficient LCL. These results show that LFA-1 expression is not essential for B cell responses to B cell growth and differentiation factors.

Recombinant human interleukin 5 is an eosinophil differentiation factor but has no activity in standard human B cell growth factor assays

Following the observation that mouse interleukin 5 (IL5) is active as a B cell growth factor (BCGF) as well as an eosinophil differentiation factor, this work was carried out to test recombinant human IL5 for BCGF activity. A highly active, partially purified batch of recombinant human IL5 was prepared and tested for BCGF activity in four laboratories. This batch gave a 50% endpoint of 1:77,450 in the human eosinophil differentiation assay, 1:983 in the mouse eosinophil differentiation assay and 1:42 in the mouse BCL1 assay, thus demonstrating that, like mouse IL5, human IL5 has cross-species activity. By comparison with the assays in the mouse this batch would be expected to have 50% maximal human BCGF activity of about 1:4000. In each assay a known positive factor was used as a positive control, and there was no inhibitory activity in the preparation. However, despite the activity towards the mouse B cell lymphoma, the results showed no detectable activity in a panel of assays used to identify human BCGF and B cell differentiation factors. These assays included (a) proliferation assays with tonsillar or splenic B cells in the presence of the co-stimulators anti-mu or phorbol myristate acetate; (b) a restimulation assay in which tonsillar B cells are first activated with either Staphylococcus aureus Cowan 1 or a mixture of phorbol dibutyrate and ionomycin, or splenic B cells are first activated with anti-mu; (c) production of immunoglobulin by B cells in a restimulation assay with Staphylococcus aureus Cowan 1; (d) production of immunoglobulin by the Epstein-Barr virus-transformed B lymphoblastoid CESS cell line; (e) the ability to stimulate proliferation of chronic lymphocytic leukemia (B-CLL) cells freshly explanted from three different patients; (f) the ability to stimulate the B lymphoma (L4) cell line and the mature B cell (HBF1) line, and (g) the ability to replace T cells in specific antibody responses. It therefore seems unlikely that recombinant human IL5 is either a growth or a differentiation factor for human B cells, and raises the interesting question of the biological significance of the BCGF activity of this factor in the mouse.

Arteritis in cardiac rejection after transplantation

During a 4-year experience with cardiac transplantation, 33 hearts were obtained by autopsy or surgical resection for retransplantation. Arteritis was a feature common to all rejected hearts (14 of 14), but was absent in explanted hearts without rejection (0 of 19) (p = 0.001). Monitoring of acute cardiac rejection by endomyocardial biopsy (863 biopsies) was also reviewed, with special reference to the incidence of arteritis. Among the 16 patients with arteritis on 1 or more biopsies, 44% (7 patients, confidence limits 29 to 60%) suffered fatal rejection or underwent retransplantation because of irreversible rejection. Arteritis was seen in the small vessels obtained by endomyocardial biopsy in 4 of 5 persons who underwent biopsy within 3 days of death or retransplantation due to rejection and on none of the 6 persons who underwent biopsy within 3 days of death or retransplantation for causes other than rejection. Thus, arteritis is an important indicator for severe acute rejection, and although often reversible, may identify patients at higher risk for fatal rejection. Arteritis occurred in transplanted hearts subjected to varying combinations of cyclosporine, azathioprine and steroid therapy and could not be correlated with any drug regimen.

The response of selected human B cell lines to B cell growth and differentiation factors

Fifteen human B cell lines were tested for their ability to respond to B cell growth and differentiation factors present in phytohemagglutinin-conditioned medium. Five lines responded significantly: CESS showed an increase in IgG production only, HFB1 and BALM1 showed an increase in proliferation only and L4 and BALM4 showed an increase in both IgG production and proliferation. When four of the responding lines (CESS, HFB1, L4 and BALM4) were cultured with human recombinant-derived interleukin 1, interleukin 2, interleukin 4 or interferon-gamma no significant response was seen. CESS, L4 and BALM4 all increased IgG production in response to partially purified B cell growth factor (Cellular Products, Inc., Sera-Lab., Crawley Down, GB) and B cell differentiation factor-containing supernatant from the T24 bladder carcinoma cell line. HFB1, L4 and BALM4 all showed increased tritiated thymidine incorporation in response to purified B cell growth factor but not in response to B cell differentiation factor-containing supernatant. These lines may prove useful in the study of B cell growth and differentiation factors and their receptors.

T cell help in human antigen-specific antibody responses can be replaced by interleukin 2

Recombinant IL 2, and immunosorbent/high performance liquid chromatography-purified interleukin 2 (IL 2) obtained from the human T cell leukemic line Jurkat, but not interferon-alpha or -gamma, were able to substitute for T cells in specific antibody responses to influenza virus by T cell-depleted (E-) human peripheral blood mononuclear cells, and resulted in antibody formation equivalent to that obtained in the presence of T cells. The antibody response was shown to be antigen specific by using two non-cross-reacting strains of influenza virus (A/X31 and B/HK). IL 2 in this assay therefore functions as a T cell-replacing factor. Less than 1% of T (UCHT1+) cells were present in the E- preparations, and this number did not increase during the 7-day culture with antigen and IL 2. Because the frequency of T helper cells for X31 is known to be less than 5 X 10(-5), this low number of contaminating cells excluded indirect action of IL 2 through antigen-specific T helper cells. Three to four times less IL 2 was required for antibody production by E- cells than was needed for optimal proliferation by an IL 2-dependent T cell line. Moreover, the concentration of anti-Tac required for 50% inhibition of the IL 2-induced antibody response was 50 times less than required for 50% inhibition of IL 2-dependent proliferation by the T cell line. But when T cells were added back to the E- cells, the anti-Tac inhibition curve shifted back to that obtained with the T cell line. In cell labeling experiments, Leu 11+ cells but not HNK1+ cells were increased in E- cells cultured with antigen and IL 2. This increase in Leu 11+ cells was abolished by prior passage of the E- cells through Sephadex G-10 columns without affecting the IL 2-induced antibody response. From these experiments we conclude that IL 2 can replace T cells in specific antibody responses, and that the IL 2 effect is not mediated indirectly through T cells or large granular lymphocytes.

B cell growth and differentiation induced by supernatants of transformed epithelial cell lines

Growth and differentiation of B cells is thought to be regulated by soluble factors derived from T cells. However, human T cell lines and hybridomas have proved to be notoriously unreliable and unstable sources of such factors. We report here that three stable human bladder carcinoma cell lines T24, RT4 and 5637 produce, in a constitutive fashion, factors which promote growth and differentiation of human B cells.

Selection criteria for drug-treated animals in two-kidney, one clip renal hypertension

The two-kidney, one clip (2K1C) model of hypertension in the rat does not uniformly result in increased blood pressure. That is, the placement of a clip around one renal artery in a two-kidney rat will usually, but not always, produce hypertension. This is an important problem in studies designed to evaluate the ability of antihypertensive therapy to prevent hypertension. Therefore, an additional objective means other than blood pressure is needed to assess animals that are treated from the outset with antihypertensive therapy. The purpose of this study was to correlate the relative fresh weights of left (clipped)/right (nonclipped) kidneys (LK/RK) with tail-cuff systolic blood pressure in the 2K1C model of renal hypertension and to identify an LK/RK range that would exclude the animals least likely to become hypertensive (failures of the clipping procedure). On a scale of 0.0 to 1.0, an LK/RK ratio of 0.0 was present when the clipped kidney was completely infarcted or atrophied and a ratio of 1.0 was present when the clip did not cause sufficient renal artery stenosis to alter kidney weight. In a series of 72 untreated 2K1C male Sprague-Dawley rats examined 6 to 8 weeks after clipping, 100% of the animals with an LK/RK ratio of 0.5 to 0.8 (n = 19) and 75% with an LK/RK ratio of 0.4 to 0.9 (n = 38) had a blood pressure greater than 150 mm Hg. Less than 50% with an LK/RK ratio below 0.4 or above 0.9 (n = 34) were hypertensive.(ABSTRACT TRUNCATED AT 250 WORDS)