Gait studies of patients with flat feet

Many patients are referred to the outpatients department with ‘flat feet’, but it is generally accepted that a small proportion, if not treated, will produce pain and disability in later life. The great toe extension test is used as a screening test to identify this small group, a negative test indicating failure of normal mechanical functioning of the plantar-aponeurosis.This paper aims to validate this test by demonstrating, by biomechanical analysis, that the foot with the abnormal great toe extension test shows abnormal forces and moments generated around the ankle joint during walking.     

Juvenile amyopathic dermatomyositis

We report a 15-year-old girl with a 10-year-old history of typical skin features of dermatomyositis (DM) without evidence of muscle involvement. Amyopathic dermatomyositis(ADM) is defined by the presence of biopsy confirmed classic cutaneous findings of dermatomyositis in the absence of any clinical or laboratory signs of muscle disease for at least 2 years after onset of skin pathology. To exclude muscle involvement muscle enzymes should be normal; moreover additional use of magnetic resonance imaging and muscle ultrasound is currently being proposed. It is as yet undetermined. whether early aggressive immunosuppressive treatment of ADM might prevent the development of myositis at a later date or influence the course of the skin disease. In a paediatric patient with ADM we advocate a more expectant attitude with careful and regular monitoring for possible development of muscle disease.     

Interstitial hyperthermia in combination with brachytherapy

Flexible coaxial cables were modified to serve as microwave antennas operating at a frequency of 915 MHz. These antennas were inserted into nylon afterloading tubes that had been implanted in tumors using conventional interstitial implantation techniques for iridium-192 seed brachytherapy. The tumor volume was heated to 42-45 degrees C within 15 minutes and heating was continued for a total of 1 hour per treatment. Immediately following a conventional brachytherapy dose and removal of the iridium seeds the tumors were heated again in a second treatment. This interstitial technique for delivering local hyperthermia should be compatible with most brachytherapy methods. The technique has proved so far to be practical and without complications. Temperature distributions obtained in tissue phantoms and a patient are described.     

The Effect of Hemorrhage on Plasma Iron Turnover

The plasma iron turnover rate in rats following a single hemorrhage reachesa maximum in about 48 hours and returns to normal between the seventh andtenth day. There is considerable variation in individual rats in both the maximum rate attained and the time required for recovery. No significant difference in response was observed due to the severity of hemorrhage uponremoval of 2.7 to 18 per cent of total red cells.

Submitted on June 20, 1960 Accepted on November 20, 1960     

Dissociation of hypertension and genetically enhanced cell growth capacity in skin fibroblasts of F2 hybrid spontaneously hypertensive rats/Wistar-Kyoto rats.

Skin fibroblasts from newborn spontaneously hypertensive rats (SHR) grow faster in culture than Wistar-Kyoto rat (WKY) cells. Similar results have been described for vascular smooth muscle cells from prehypertensive and adult SHR. This suggests the existence of an intrinsic abnormality in vascular and nonvascular cells of mesodermal origin affecting cell growth control in those rats. In an attempt to determine the relation between high blood pressure and this trait, we cultured skin fibroblasts from adult SHR, WKY, F1, and F2 hybrid SHR/WKY populations by explant technique. Their growth capacity was determined by culture well DNA doubling time and by [3H]thymidine incorporation. Adult SHR fibroblasts grew more quickly (doubling time [DT] = 37.2 +/- 2.3 h, n = 8) than WKY ones (DT = 53.9 +/- 3.6 h, n = 6). Female SHR were crossed with male WKY to produce an F1 and an F2 hybrid generation presenting a Mendelian distribution of blood pressure. Skin fibroblasts were cultured from 21 rats belonging to the highest and the lowest blood pressure groups. No difference was observed between the two groups in either growth (DT = 47.5 +/- 4.1 h, n = 11 v DT = 44.6 +/- 3.2 h, n = 10) or epidermal growth factor-induced [3H]thymidine incorporation. These observations suggest that the increased growth capacity observed in SHR is not a determinant of high blood pressure initiation but may be involved in early cardiovascular enlargement.     

Improved surface coil imaging in MR: decoupling of the excitation and receiver coils

We obtained magnetic resonance images with good sensitivity and radio frequency (RF) uniformity using separate transmitter and receiver coils. The excitation, namely, the rotation of the magnetization vector into a plane perpendicular to the magnetic field, was done by applying a homogeneous RF magnetic field produced by a large saddle-shaped coil. Surface coils were used for detection only. Because two coils that operated on the same resonance frequency were used, a coupling problem developed. This problem, which involved inhomogeneity of the RF magnetic field caused by the large current induced in the surface coil during excitation, could only be solved by minimizing the mutual inductance or maximizing the impedance of the surface coil resonance circuit during excitation. We were able to solve this problem using an electronic detuning method.     

IL-15 transpresentation promotes both human T-cell reconstitution and T-cell-dependent antibody responses in vivo

Cytokine immunotherapies targeting T lymphocytes are attractive clinical interventions against viruses and tumors. In the mouse, the homeostasis of memory α/β CD8⁺ T cells and natural killer (NK) cells is significantly improved with increased IL-15 bioavailability. In contrast, the role of “transpresented” IL-15 on human T-cell development and homeostasis in vivo is unknown. We found that both CD8 and CD4 T cells in human immune system (HIS) mice are highly sensitive to transpresented IL-15 in vivo, with both naïve (CD62L⁺CD45RA⁺) and memory phenotype (CD62L⁻CD45RO⁺) subsets being significantly increased following IL-15 “boosting.” The unexpected global improvement in human T-cell homeostasis involved enhanced proliferation and survival of both naïve and memory phenotype peripheral T cells, which potentiated B-cell responses by increasing the frequency of antigen-specific responses following immunization. Transpresented IL-15 did not modify T-cell activation patterns or alter the global T-cell receptor (TCR) repertoire diversity. Our results indicate an unexpected effect of IL-15 on human T cells in vivo, in particular on CD4⁺ T cells. As IL-15 promotes human peripheral T-cell homeostasis and increases the frequency of neutralizing antibody responses in HIS mice, IL-15 immunotherapy could be envisaged as a unique approach to improve vaccine responses in the clinical setting.In vivo studies of lymphocyte development, homeostasis, and immune responses upon infection, antigenic challenge, or following vaccination have been largely characterized in mice. Although this line of experimentation is valuable, 60 million years of evolution have generated important differences between murine and human immune systems, and therefore some of the knowledge derived from mouse models may not be directly applicable to humans. An intermediate between murine and human in vivo studies exists in the form of human immune system (HIS) mice. A recently developed HIS mouse model involves engraftment of newborn BALB/c Rag2^−/− γ_c^−/− mice with human hematopoietic stem cells (HSCs) from fetal liver or cord blood, which generates human innate and adaptive lymphocytes and dendritic cell subsets required for immune responses (1–3). HIS mice are proving to be a very powerful biotechnology, and although they are successfully used to model human hematopoiesis, their capacity for studying human immune responses is suboptimal (2). This is likely due to perturbed homeostasis of human T cells in BALB/c Rag2^−/− γ_c^−/− HIS mice, as these cells exhibit an abnormally high turnover rate and fail to accumulate (1–5). Not surprisingly, many current efforts are focused on improving human T-cell reconstitution and homeostasis in HIS mice with the ultimate goal of inducing robust and consistent human immune responses in vivo.T-cell homeostasis comprises T-cell generation in the thymus, export to the periphery, maintenance of the peripheral naïve T-cell pool, and regulation of activated effector and memory T-cell compartments (6). Several signals have been implicated in controlling T-cell homeostasis, including those emanating from the T-cell receptor (TCR) following interactions with self-peptide + major histocompatibility complex (pMHC) and those induced by growth factors, including cytokines (6). The common cytokine receptor gamma chain (γ_c) family of cytokines (which comprises IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21) in particular have been demonstrated to play a role in T-cell homeostasis in mammals (7). Humans and mice possessing mutations in genes encoding the γ_c, Jak3 (both critical for signal transduction following binding γ_c cytokines) or the alpha chain of the IL-7 receptor (IL-7Rα), display a severe block in T-cell development and resulting severe combined immunodeficiency (8, 9). The γ_c-dependent cytokine IL-15 is unusual because its bioactive form is a functional complex associated with the IL-15Rα chain. Thus, cells expressing IL-15 such as monocytes, dendritic cells, and stromal cells must also coexpress the IL-15Rα to “transpresent” IL-15 to IL-15–responsive cells (that express the IL-2Rβ/γ_c complex). Accordingly, both IL-15 and IL-15Rα are up-regulated on myeloid cells following inflammation, thereby increasing IL-15 bioavalability (10–12).We demonstrated that transpresented murine IL-15 inefficiently triggered human natural killer (NK) cells in vitro and in vivo providing an explanation for the poor human NK cell reconstitution in BALB/c Rag2^−/− γ_c^−/− HIS mice (3). Exogenous administration of a potent human IL-15R agonist (referred to as RLI, consisting of human IL-15 covalently linked to an extended human IL-15Rα “sushi” domain thus mimicking IL-15 transpresentation) (13–15) was sufficient to restore human NK cell development in HIS mice (3). Whereas memory CD8⁺ T cells in mice are highly responsive to exogenous IL-15 (6, 11–14), naïve CD4⁺ and CD8⁺ T cells are not thought to require IL-15 for normal homeostasis (6, 11–14). However, in vivo effects of human IL-15 on human T cells have not been studied, and it remained possible that the poor reactivity of human T cells to mouse IL-15 might also contribute to the low human T-cell reconstitution in the HIS mouse model. Here we show that human IL-15 transpresentation increases human T-cell reconstitution and the frequency of T-cell–dependent antibody responses in HIS mice. These studies provide a first preclinical trial of transpresented human IL-15 on human T cells in vivo and indicate that increased IL-15 bioavailability globally boosts human naïve and memory T-cell homeostasis in this humanized mouse model. Our findings offer a unique approach to study human T-cell immune responses in vivo and suggest that IL-15 immunotherapy may be useful to promote global T-cell reconstitution in humans.     

TLR9 bone marrow chimeric mice define a role for cerebral TNF in neuroprotection induced by CpG preconditioning

Systemic preconditioning with the TLR9 ligand CpG induces neuroprotection against brain ischemic injury through a tumor necrosis factor (TNF)-dependent mechanism. It is unclear how systemic administration of CpG engages the brain to induce the protective phenotype. To address this, we created TLR9-deficient reciprocal bone marrow chimeric mice lacking TLR9 on either hematopoietic cells or radiation-resistant cells of nonhematopoietic origin. We report that wild-type mice reconstituted with TLR9-deficient hematopoietic cells failed to show neuroprotection after systemic CpG preconditioning. Further, while hematopoietic expression of TLR9 is required for CpG-induced neuroprotection it is not sufficient to restore protection to TLR9-deficient mice that are reconstituted with hematopoietic cells bearing TLR9. To determine whether the absence of protection was associated with TNF, we examined TNF levels in the systemic circulation and the brain. We found that although TNF is required for CpG preconditioning, systemic TNF levels did not correlate with the protective phenotype. However, induction of cerebral TNF mRNA required expression of TLR9 on both hematopoietic and nonhematopoietic cells and correlated with neuroprotection. In accordance with these results, we show the therapeutic potential of intranasal CpG preconditioning, which induces brain TNF mRNA and robust neuroprotection with no concomitant increase in systemic levels of TNF.