Therapy of patients with human T-cell lymphotrophic virus I-induced adult T-cell leukemia with anti-Tac, a monoclonal antibody to the receptor for interleukin-2

Human T-cell lymphotropic virus I (HTLV-I)-induced adult T-cell leukemia (ATL) cells constitutively express interleukin-2 (IL-2) receptors identified by the anti-Tac monoclonal antibody (MoAb), whereas normal resting cells do not. This observation provided the scientific basis for a trial of intravenous anti-Tac in the treatment of nine patients with ATL. The patients did not suffer untoward reactions and did not have a reduction in the normal formed elements of the blood, and only one of the nine produced antibodies to the anti-Tac MoAb. Three patients had transient mixed, partial, or complete remissions lasting from 1 to more than 8 months after anti-Tac therapy, as assessed by routine hematologic tests, immunofluorescence analysis of circulating cells, and molecular genetic analysis of HTLV-I provirus integration and of the T-cell receptor gene rearrangement. The precise mechanism of the antitumor effects is unclear; however, the use of a MoAb that prevents the interaction of IL-2 with its receptor on ATL cells provides a rational approach for the treatment of this malignancy.     

Glycosylphosphatidylinositol-anchored H-2Db molecules are defective in antigen processing and presentation to cytotoxic T lymphocytes

Glycosylphosphatidylinositol-anchored (GPI)-D^b molecules are defective in mediating cytotoxic T lymphocytes (CTL) lysis of transfected lymphoma cells, compared to their transmembrane (TM) counterpart. This defect is manifest when antigenic peptide must be processed and presented through the endogenous pathway. These same transfectants can be lysed by allospecific CTL, or by antigen-specific D^b-restricted CTL when pulsed with appropriate exogenous synthetic peptide, demonstrating that they can bind and present peptide for CTL-mediated lympholysis. The defect apparently results from differences between GPI-D^b and TM-D^b assembly and transport, or from differences in membrane topology that affect CD8⁺ CTL recognition of major histocompatibility complex/peptide complex.     

An educational intervention to update health workers about HIV and infant feeding

Clinical guidelines are used to translate research findings into evidence‐based clinical practice but are frequently not comprehensively adopted by health workers (HWs). HIV and infant feeding guidelines were revised by the World Health Organization to align feeding advice for HIV‐exposed and unexposed infants, and these were adopted in South Africa in 2017. We describe an innovative, team‐based, mentoring programme developed to update HWs on these guidelines. The intervention was underpinned by strong theoretical frameworks and aimed to improve HWs' attitudes, knowledge, confidence, and skills about breastfeeding in the context of HIV. On‐site workshops and clinical mentoring used interactive participatory methods and a simple low‐tech approach, guided by participants' self‐reported knowledge gaps. Workshops were conducted at 24 participating clinics over three sessions, each lasting 1–2 hr. Evaluation data were collected using a self‐administered questionnaire. Of 303 participating HWs, 249/303 (82.2%) attended all workshops. Achieving high workshop attendance was challenging and “catch‐up” sessions were required to achieve good coverage. Common knowledge gaps identified included antiretroviral therapy adherence monitoring during breastfeeding and management of viral load results (173 participants), management of breast conditions (79), and advice about expressing and storing breastmilk (64). Most participants reported all their knowledge gaps were addressed and anticipated that their practice would change. We describe a feasible, sustainable approach to updating HWs on HIV and infant feeding guidelines and improving skills in breastfeeding counselling in resource‐constrained settings. This approach could be adapted to other topics and, with further evaluation, implemented at scale using existing resources.     

In vivo characterization of emerging white matter microstructure in the fetal brain in the third trimester

The third trimester of pregnancy is a period of rapid development of fiber bundles in the fetal white matter. Using a recently developed motion‐tracked slice‐to‐volume registration (MT‐SVR) method, we aimed to quantify tract‐specific developmental changes in apparent diffusion coefficient (ADC), fractional anisotropy (FA), and volume in third trimester healthy fetuses. To this end, we reconstructed diffusion tensor images from motion corrected fetal diffusion magnetic resonance imaging data. With an approved protocol, fetal MRI exams were performed on healthy pregnant women at 3 Tesla and included multiple (2–8) diffusion scans of the fetal head (1–2 b = 0 s/mm² images and 12 diffusion‐sensitized images at b = 500 s/mm²). Diffusion data from 32 fetuses (13 females) with median gestational age (GA) of 33 weeks 4 days were processed with MT‐SVR and deterministic tractography seeded by regions of interest corresponding to 12 major fiber tracts. Multivariable regression analysis was used to evaluate the association of GA with volume, FA, and ADC for each tract. For all tracts, the volume and FA increased, and the ADC decreased with GA. Associations reached statistical significance for: FA and ADC of the forceps major; volume and ADC for the forceps minor; FA, ADC, and volume for the cingulum; ADC, FA, and volume for the uncinate fasciculi; ADC of the inferior fronto‐occipital fasciculi, ADC of the inferior longitudinal fasciculi; and FA and ADC for the corticospinal tracts. These quantitative results demonstrate the complex pattern and rates of tract‐specific, GA‐related microstructural changes of the developing white matter in human fetal brain.     

CCL2/Monocyte Chemoattractant Protein-1 regulates inflammatory responses critical to healing myocardial infarcts

The CC chemokine Monocyte Chemoattractant Protein (MCP)-1/CCL2 has potent mononuclear cell chemo-attractant properties, modulates fibroblast and endothelial cell phenotype and may play an important role in wound healing. In order to examine whether MCP-1 critically regulates myocardial infarct healing, we studied the effects of MCP-1 gene disruption and antibody neutralization in a closed-chest model of reperfused murine myocardial infarction. MCP-1-/- mice had decreased and delayed macrophage infiltration in the healing infarct and demonstrated delayed replacement of injured cardiomyocytes with granulation tissue. In contrast, the time course and density of neutrophil infiltration was similar in MCP-1 null and wild-type animals. MCP-1-/- infarcts had decreased mRNA expression of the cytokines TNF-alpha, IL-1beta, TGF-beta2, -beta3, and IL-10 and demonstrated defective macrophage differentiation evidenced by decreased Osteopontin-1 expression. MCP-1 deficiency diminished myofibroblast accumulation but did not significantly affect infarct angiogenesis. Despite showing delayed phagocytotic removal of dead cardiomyocytes, MCP-1-/- mice had attenuated left ventricular remodeling, but similar infarct size when compared with wild-type animals. MCP-1 antibody inhibition resulted in defects comparable with the pathological findings noted in infarcted MCP-1-/- animals without an effect on macrophage recruitment. MCP-1 has important effects on macrophage recruitment and activation, cytokine synthesis and myofibroblast accumulation in healing infarcts. Absence of MCP-1 results in attenuated post-infarction left ventricular remodeling, at the expense of a prolonged inflammatory phase and delayed replacement of injured cardiomyocytes with granulation tissue.     

Progress in the diagnosis of deep venous thrombosis: the efficacy of real-time B-mode ultrasonic imaging

Seventy-six limbs with clinically suspected acute deep venous thrombosis (DVT) were evaluated by means of ultrasonic imaging (UI) to define the ability of this technique to detect acute and chronic venous obstruction and to determine the origin and distribution of venous thrombi. UI was compared with ascending contrast phlebography in 46 limbs and was found to be 100% accurate in detecting both acute and chronic venous thrombosis. Overall, acute DVT was present in 63 of 76 limbs (83%) studied. Acute DVT was found in 24% and recurrent acute DVT in 76%. Our results indicate that although the calf veins are the most common site of involvement (89%), thrombi may frequently arise simultaneously in multiple anatomic sites. All limbs with recurrent acute DVT had evidence of previous calf thrombi but only 13% had previous proximal disease. This suggests that asymptomatic calf DVT is common and the prevalence of recurrent acute DVT is significantly greater than previously believed. We found UI is a practical, accurate, non-invasive method for investigating the pathogenesis of venous disease.     

Use of ultrasonic venography in the evaluation of venous valve function

Forty healthy limbs and 31 limbs with suspected deep venous insufficiency were imaged with real-time B-mode ultrasound to determine valve location, anatomic characteristics, and function. Valve function was evaluated by comparison with Doppler ultrasonographic techniques, and the data clearly indicated that ultrasonic venography accurately localized and determined the extent of deep venous reflux. Ascending contrast venography was performed in 15 postphlebitic limbs for assessment of valve location. The results indicate that ultrasonic venography is a more accurate method for visualization of valves in this group of patients. Therefore, ultrasonographic imaging is a valuable technique for evaluating limbs with chronic venous insufficiency.