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We examined how the relationship between maternal education and child health varies across women’s status and safety using pooled Demographic and Health Survey data from 24 sub-Saharan African countries. While maternal education was associated with less child stunting, wasting, and underweight, the effect of maternal education on stunting and underweight was attenuated among women who experienced high levels of intimate partner violence (IPV). Further, the positive influence of maternal education on stunting and underweight was less pronounced among women who lived in communities with higher levels of IPV, even after controlling for women’s own IPV. This suggests that the returns of maternal education may be dampened in the presence of IPV. The fact that this link operates at both individual and community levels underscores how gender norms, patriarchy, and gender-based violence stifle progress on children’s health. The results also demonstrate how the UN Sustainable Development Goals strengthening maternal education, improving child health, and reducing intimate partner violence must be jointly pursued and the importance of considering how child health outcomes may be tempered by context.

Sporadic Creutzfeldt-Jakob disease (sCJD), the most common human prion disease, is transmissible through iatrogenic routes due to abundant infectious prions [misfolded forms of the prion protein (PrPSc)] in the central nervous system (CNS). Some epidemiological studies have associated sCJD risk with non-CNS surgeries. We explored the potential prion seeding activity and infectivity of skin from sCJD patients. Autopsy or biopsy skin samples from 38 patients [21 sCJD, 2 variant CJD (vCJD), and 15 non-CJD] were analyzed by Western blotting and real-time quaking-induced conversion (RT-QuIC) for PrPSc. Skin samples from two patients were further examined for prion infectivity by bioassay using two lines of humanized transgenic mice. Western blotting revealed dermal PrPSc in one of five deceased sCJD patients and one of two vCJD patients. However, the more sensitive RT-QuIC assay detected prion seeding activity in skin from all 23 CJD decedents but not in skin from any non-CJD control individuals (with other neurological conditions or other diseases) during blinded testing. Although sCJD patient skin contained ~103- to 105-fold lower prion seeding activity than did sCJD patient brain tissue, all 12 mice from two transgenic mouse lines inoculated with sCJD skin homogenates from two sCJD patients succumbed to prion disease within 564 days after inoculation. Our study demonstrates that the skin of sCJD patients contains both prion seeding activity and infectivity, which raises concerns about the potential for iatrogenic sCJD transmission via skin.

Background Talactoferrin alfa is an oral dendritic cell (DC)-mediated immunotherapy (DCMI). We tested whether talactoferrin was superior to placebo in advanced non-small-cell lung cancer (NSCLC). Patients and methods An FORTIS-M trial was an international, multicenter, randomized, double-blind comparison of talactoferrin (1.5g p.o. BID) versus placebo BID, in patients with stage IIIB/IV NSCLC whose disease had failed two or more prior regimens. Treatment was administered for a maximum of five 14-week cycles. The primary efficacy end point was overall survival (OS); secondary end points included 6- and 12-month survival, progression-free survival (PFS), and disease control rate (DCR). Results Seven hundred and forty-two patients were randomly assigned (2:1) to talactoferrin (497) or placebo (245). The median OS in the intent-to-treat (ITT) population was 7.66 months in the placebo arm and 7.49 months in the talactoferrin arm [hazard ratio (HR), 1.04; 95% CI, 0.873–1.24; P = 0.6602]. The 6-month survival rates were 59.9% (95% CI, 53.4% to 65.8%) and 55.7% (95% CI, 51.1% to 59.9%), respectively. The 12-month survival rates were 32.2% (95% CI, 26.3% to 38.2%) and 30.9% (95% CI, 26.8% to 35%), respectively. The median PFS rates were 1.64 months and 1.68 months, respectively (HR, 0.99; 95% CI, 0.835–1.16; P = 0.8073). The DCRs were 38.4 and 37.6%, respectively [stratified odds ratio (OR), 0.96; 95% CI, 0.698–1.33; P = 0.8336]. The safety profiles were comparable between arms. Conclusions There was no improvement in efficacy with talactoferrin alfa in patients with advanced NSCLC whose disease had failed two or more previous regimens.

Background Rigosertib (ON 01910.Na), a first-in-class Ras mimetic and small-molecule inhibitor of multiple signaling pathways including polo-like kinase 1 (PLK1) and phosphoinositide 3-kinase (PI3K), has shown efficacy in preclinical pancreatic cancer models. In this study, rigosertib was assessed in combination with gemcitabine in patients with treatment-naive metastatic pancreatic adenocarcinoma. Materials and methods Patients with metastatic pancreatic adenocarcinoma were randomized in a 2:1 fashion to gemcitabine 1000 mg/m2 weekly for 3 weeks of a 4-week cycle plus rigosertib 1800 mg/m2 via 2-h continuous IV infusions given twice weekly for 3 weeks of a 4-week cycle (RIG + GEM) versus gemcitabine 1000 mg/m2 weekly for 3 weeks in a 4-week cycle (GEM). Results A total of 160 patients were enrolled globally and randomly assigned to RIG + GEM (106 patients) or GEM (54). The most common grade 3 or higher adverse events were neutropenia (8% in the RIG + GEM group versus 6% in the GEM group), hyponatremia (17% versus 4%), and anemia (8% versus 4%). The median overall survival was 6.1 months for RIG + GEM versus 6.4 months for GEM [hazard ratio (HR), 1.24; 95% confidence interval (CI) 0.85–1.81]. The median progression-free survival was 3.4 months for both groups (HR = 0.96; 95% CI 0.68–1.36). The partial response rate was 19% versus 13% for RIG + GEM versus GEM, respectively. Of 64 tumor samples sent for molecular analysis, 47 were adequate for multiplex genetic testing and 41 were positive for mutations. The majority of cases had KRAS gene mutations (40 cases). Other mutations detected included TP53 (13 cases) and PIK3CA (1 case). No correlation between mutational status and efficacy was detected. Conclusions The combination of RIG + GEM failed to demonstrate an improvement in survival or response compared with GEM in patients with metastatic pancreatic adenocarcinoma. Rigosertib showed a similar safety profile to that seen in previous trials using the IV formulation.

Parasites and hosts live in communities consisting of many interacting species, but few studies have examined how communities affect parasite virulence and transmission. We studied a food web consisting of two species of milkweed, two milkweed herbivores (monarch butterfly and oleander aphid) and a monarch butterflyspecific parasite. We found that the presence of aphids increased the virulence and transmission potential of the monarch butterflys parasite on one milkweed species. These increases were associated with aphid-induced decreases in the defensive chemicals of milkweed plants. Our experiment suggests that aphids can indirectly increase the virulence and transmission potential of monarch butterfly parasites, probably by altering the chemical composition of a shared food plant. These results indicate that species that are far removed from host‐parasite interactions can alter such interactions through cascading indirect effects in the food web. As such, indirect effects within ecological communities may drive the dynamics and evolution of parasites.

The polypeptide N-α-acetylgalactosaminyltransferases (ppGalNAcTs) play a key role in mucin-type O-linked glycan biosynthesis by installing the intial GalNAc residue on the protein scaffold. The preferred substrates and functions of the >20 isoforms in mammals are not well understood. However, current data suggest that glycosylated mucin domains are created by the successive, often hierarchical, action of several specific ppGalNAcTs. Herein we analyzed the glycopeptide substrate preferences of several ppGalNAcT family members using a library screening approach. A 56-member glycopeptide library designed to reflect a diversity of glycan clustering was assayed for substrate activity with ppGalNAcT isoforms using an azido-ELISA. The data suggest that the ppGalNAcTs can be classified into at least four types, which working together, are able to produce densely glycosylated mucin glycoproteins.

Objective: To review the morphological features of salivary gland fine-needle aspirates (FNA) on ThinPrep® (TP) preparations. Emphasis is placed on the commonalities and specific differences between TP and conventional smear (CS) preparations. Study Design: The cytology and surgical pathology archives were searched for ‘salivary' or ‘parotid' at our institution from 2003 to 2013 for cases processed by TP and with a range of specified diagnoses and surgical follow-up. These cases were reviewed by the authors. A review of the known literature was also performed. Results: Morphological features and artifacts were noted for the most common salivary gland lesions. General features noted in the literature were identified, along with novel features identified on our review of cases. Emphasis was placed on cellular alterations, extracellular differences and architectural changes. Conclusions: The multitude of both benign and malignant lesions coupled with the unique artifacts encountered on TP makes salivary gland FNAs difficult for most practicing pathologists and cytopathologists. For this reason, many laboratories have been reluctant to implement TP preparations for these lesions. With knowledge of the specific artifacts and differences on TP compared to CS, TP can be used with confidence without a compromise in diagnostic accuracy for adequately cellular samples.

Anaemia is a common haematologic disorder in patients with cancer and has a multifactorial aetiology, including the effects of the malignancy itself and residual effects from previous therapy. Novel erythropoiesis stimulating protein (NESP, darbepoetin alfa), a protein with additional sialic acid compared with erythropoietin (EPO), stimulates erythropoiesis by the same mechanism as recombinant human erythropoietin (rHuEPO) but it is biochemically distinct. NESP, with its approximately 3-fold greater serum half-life, can maintain haemoglobin levels as effectively as rHuEPO in anaemic patients with chronic renal failure and do so with less frequent dosing. We investigated the ability of NESP to safely increase haemoglobin levels of anaemic patients with non-myeloid malignancies not receiving chemotherapy. NESP was administered under the supervision of a physician at doses of 0.5, 1.0, 2.25 or 4.5 mcg kg−1wk−1for a maximum of 12 weeks. This report includes 89 patients completing the study by November 2000. NESP was well tolerated, with no reported dose-limiting toxicities or treatment-related severe adverse events. Increasing doses of NESP corresponded with increased efficacy. The percentage (95% confidence interval) of patients responding ranged from 61% (42%, 77%) in the 1.0 mcg kg−1wk−1group to 83% (65%, 94%) in the 4.5 mcg kg−1wk−1group. © 2001 Cance Cancer Research Campaign

RATIONALE AND OBJECTIVES Magnetic resonance (MR) imaging was used for the in vivo evaluation of bihemispheric hypoxic-ischemic (HI) injury in the neonatal rat. METHODS Seven-day-old rats underwent sham surgery (n = 7) or bilateral carotid artery ligation and hypoxia (30-45 min) (n = 8). T2-weighted imaging was used to study the temporal evolution of injury. Histopathology was used to correlate injury with MR signal changes. RESULTS T2-weighted images exhibited considerable anatomic detail (0.2 mm resolution in-plane). The cortex, dorsolateral striatum and thalamus were affected, while the hippocampus was spared. Magnetic resonance signal change was seen as early as 1.5 hrs post-HI (lesion extent, 27%-39%), and reached a maximum at 48 hrs (37%-49%). Magnetic resonance imaging estimation of injury at 72 hours after HI was compared with histopathology and correlated well (r = 0.98). CONCLUSIONS The study demonstrates the feasibility of magnetic resonance imaging for in vivo evaluation of neonatal brain injury and that vulnerability in the neonatal hippocampus is strikingly different than in adult HI models.

Although the C terminus of troponin I is known to be important in myofilament Ca2+ regulation in skeletal muscle, the regulatory function of this region of cardiac troponin I (cTnI) has not been defined. To address this question, the following recombinant proteins were expressed in Escherichia coli and purified: mouse wild-type cTnI (WT cTnI; 211 residues), cTnI-(1-199) (missing 12 residues), cTnI-(1-188) (missing 23 residues), and cTnI-(1-151) (missing 60 residues). The inhibitory activity of cTnI and the mutants was tested in myofibrils, from which cTnI.cTnC was extracted by exchanging endogenous cardiac troponin with exogenous cTnT causing the Ca2+ sensitivity of the myofibrils to be lost. Addition of increasing amounts of exogenous WT cTnI or cTnI-(1-199) to cTnT-treated myofibrils at pCa 8 caused a concentration-dependent inhibition of the maximum ATPase activity. However, cTnI-(1-188) and cTnI-(1-151) inhibited this activity to about 75% and 50% of that of the WT cTnI, respectively. We also formed a complex of either WT cTnI or each of the mutants with cTnC, reconstituted the complex into the cTnT-treated myofibrils, and measured the Mg2+-ATPase activity as a function of pCa. We found that the cTnI-(1-188).cTnC complex only partially restored Ca2+ sensitivity, whereas the cTnI-(1-151).cTnC complex did not restore any Ca2+ sensitivity. Each cTnI C-terminal deletion mutant was able to bind to cTnC, as shown by urea-polyacrylamide gel-shift analysis and size exclusion chromatography. Each mutant also co-sedimented with actin. Our results indicate that residues 152-199 (C-terminal to the inhibitory region) of cTnI are essential for full inhibitory activity and Ca2+ sensitivity of myofibrillar ATPase activity in the heart.

The N-terminal region of skeletal myosin light chain-1 (MLC-1) binds to the C terminus of actin, yet the functional significance of this interaction is unclear. We studied a fragment (MLC-pep; residues 5-14) of the ventricular MLC-1. When added to rat cardiac myofibrils, 10 nM MLC-pep induced a supramaximal increase in the MgATPase activity at submaximal Ca2+ levels with no effect at low and maximal Ca2+ levels. A nonsense, scrambled sequence peptide had no effect at any pCa value. MLC-pep did not affect myosin KEDTA and CaATPase activities or actin-activated MgATPase activities in the absence or presence of tropomyosin. The MLC-pep did not alter the ability of troponin I to inhibit MgATPase activity. Moreover, when troponin I and troponin C were extracted from the myofibrils, the MLC-pep lost its ability to stimulate the ATPase rate. This effect was fully restored upon reconstitution of the extracted myofibrils with troponin I-troponin C complex. Thus, activation of MgATPase activity by the peptide required a full complement of thin filament regulatory proteins. Interestingly, the stimulatory effect occurred at a ratio of 4 peptides to 1 thin filament, suggesting that the peptide engages in a highly cooperative process that may involve activation of the entire thin filament.

The majority of human immunodeficiency virus (HIV)-seropositive patients develop bone marrow abnormalities associated with hematopoietic malfunction during the progression of disease. One important manifestation of HIV-associated hematopoietic dysfunction is that after myelosuppression, bone marrow recovery, a process known to be mediated in part by the production of stromal cell-derived hematopoietic growth factors, is impaired. We sought to test the hypothesis that bone marrow stromal cells are infected by HIV-1 in vivo and that production of certain stromal cell-derived hematopoietic growth factors is deficient as a consequence. In this report, we demonstrate that bone marrow microvascular endothelial cells (MVEC), a key element of the stroma, are the predominant cells infected by HIV (5% to 20%) in bone marrow stromal cultures obtained from 11 consecutive HIV-seropositive patients. Although HIV-infected stromal cultures enriched for MVEC constitutively express normal levels of interleukin (IL)-4, IL-6, granulocyte (G)-colony-stimulating factor (CSF), granulocyte-macrophage (GM)-CSF, tumor necrosis factor (TNF)- alpha, transforming growth factor (TGF)-beta, and Steel factor, IL-1 alpha-induced release of IL-6 and G-CSF is significantly reduced in these cultures. These observations suggest that HIV infection of bone marrow MVEC reduces the capacity of hematopoietic stroma to respond to regulatory signals that normally augment blood cell production during periods of increased demand.

Parasites often produce large numbers of offspring within their hosts. High parasite burdens are thought to be important for parasite transmission, but can also lower host fitness. We studied the protozoan Ophryocystis elektroscirrha, a common parasite of monarch butterflies (Danaus plexippus), to quantify the benefits of high parasite burdens for parasite transmission. This parasite is transmitted vertically when females scatter spores onto eggs and host plant leaves during oviposition; spores can also be transmitted between mating adults. Monarch larvae were experimentally infected and emerging adult females were mated and monitored in individual outdoor field cages. We provided females with fresh host plant material daily and quantified their lifespan and lifetime fecundity. Parasite transmission was measured by counting the numbers of parasite spores transferred to eggs and host plant leaves. We also quantified spores transferred from infected females to their mating partners. Infected monarchs had shorter lifespans and lower lifetime fecundity than uninfected monarchs. Among infected females, those with higher parasite loads transmitted more parasite spores to their eggs and to host plant leaves. There was also a trend for females with greater parasite loads to transmit more spores to their mating partners. These results demonstrate that high parasite loads on infected butterflies confer a strong fitness advantage to the parasite by increasing between-host transmission.

A large family of uridine 5'-diphosphate (UDP)-alpha-N-acetylgalactosamine (GalNAc):polypeptide N-acetylgalactosaminyl transferases (ppGalNAc Ts) initiates mucin-type O-glycan biosynthesis at serine and threonine. The peptide substrate specificities of individual family members are not well characterized or understood, leaving an inability to rationally predict or comprehend sites of O-glycosylation. Recently, a kinetic modeling approach demonstrated neighboring residue glycosylation as a major factor modulating the O-glycosylation of the porcine submaxillary gland mucin 81 residue tandem repeat by ppGalNAc T1 and T2 [Gerken et al. (2002) J. Biol. Chem. 277, 49850-49862]. To confirm the general applicability of this model and its parameters, the ppGalNAc T1 and T2 glycosylation kinetics of the 80+ residue tandem repeat from the canine submaxillary gland mucin was obtained and characterized. To reproduce the glycosylation patterns of both mucins (comprising 50+ serine/threonine residues), specific effects of neighboring peptide sequence, in addition to the previously described effects of neighboring residue glycosylation, were required of the model. Differences in specificity of the two transferases were defined by their sensitivities to neighboring proline and nonglycosylated hydroxyamino acid residues, from which a ppGalNAc T2 motif was identified. Importantly, the model can approximate the previously reported ppGalNAc T2 glycosylation kinetics of the IgA1 hinge domain peptide [Iwasaki, et al. (2003) J. Biol. Chem. 278, 5613-5621], further validating both the approach and the ppGalNAc T2 positional weighting parameters. The characterization of ppGalNAc transferase specificity by this approach may prove useful for the search for isoform-specific substrates, the creation of isoform-specific inhibitors, and the prediction of mucin-type O-glycosylation sites.

Received 23 October 1998; accepted in revised form 23 October 1998Cardiac troponin I (cTnI) is an essential element in activation of myofilaments by Ca2+binding to cardiac troponin C (cTnC). Yet, its role in transduction of the Ca2+binding signal to cardiac troponin T (cTnT) and tropomyosin-actin remain poorly understood. We have recently discovered that regions of cTnI C-terminal to a previously defined inhibitory peptide are essential for full inhibitory activity and Ca2+-sensitivity of cardiac myofilaments (Raricket al1997). However, apart from its role in structural binding to cTnC, there is little knowledge concerning the role of the N-terminus of cTnI in the activation and regulation of cardiac myofilaments. To address this question, we generated wild-type mouse cardiac TnI (WT-cTnI; 211 residues) and two N-terminal deletion mutants of mouse cTnI, cTnI54–211(missing 53 residues), and cTnI80–211(missing 79 residues). The cTnI54–211mutant retained the ability to bind to cTnT, but lost the ability to bind to cTnC, whereas the cTnI80–211mutant lost the ability to bind to cTnT, but bound weakly to cTnC. Both mutants bound to F-actin. In the absence of Ca2+, cTnI54–211was able to inhibit the unregulated MgATPase activity of myofibrils lacking endogenous cTnI-cTnC to the same extent as WT-cTnI, whereas cTnI80–211had some impairment of its inhibitory capability. Reconstitution with cTnI54–211/cTnC complex did not restore Ca2+-activation of myofibrillar MgATPase activity at all, however, the cTnI80–211/cTnC complex restored Ca2+-activation to nearly 50% of that obtained with WT-cTnI/cTnC. These data provide the first evidence of a significant function of a cTnT-binding domain on cTnI. They also indicate that the structural cTnC binding site on cTnI is required for Ca2+-dependent activation of cardiac myofilaments, and that cTnT binding to the N-terminus of cTnI is a negative regulator of activation.

Treatment options for advanced ovarian cancer, a disease that is often terminal, are primarily palliative in nature and inherently expensive, presenting a dilemma for the managed care organization, whose purpose is to provide high-quality health care at a reasonable cost. Kaiser Permanente Northwest, a staff-model health maintenance organization providing care to patients in Oregon, Washington, and Idaho, has a unique approach to treating advanced ovarian cancer that involves the use of flexible evidence-based practice guidelines. These guidelines, which consist of state-of-the-art chemotherapy protocols, provide the Kaiser physician with the flexibility to treat each patient according to the particular stage and potential curability of the tumor. The Kaiser Permanente system controls costs by reducing hospital bureaucracy and encouraging treatment options that can be administered on an outpatient basis. Kaiser Permanente also makes use of multidisciplinary teams in the coordination of care and emphasizes the development of and participation in clinical research so that existing guidelines can be updated to reflect the best standards of cancer care.

Abstract —We present a current perception of the regulation of activation of cardiac myofilaments with emphasis on troponin (Tn) and tropomyosin (Tm). Activation involves both a Ca 2+ -regulated molecular switch and a potentiated state, dependent on feedback effects of force-generating crossbridges. Recent developments in the elucidation of the structure and arrangement of the myofilament proteins offer insights into the molecular interactions that constitute the switching and potentiating mechanisms. Transgenic mice overexpressing myofilament proteins, in vitro studies of mutant myofilament proteins, multidimensional multinuclear nuclear magnetic resonance, and fluorescence resonance energy transfer offer important approaches to understanding the molecular signaling processes. These studies reveal special features of the cardiac myofilament proteins that appear specialized for the unique functions of the heart. An important aspect of these special features is their role in mechanical, chemical, and neurohumoral coupling processes that tune myofilament activation to hemodynamics and beating frequency. Understanding these processes has become essential to understanding cardiac pathologies such as heart failure, ischemia and reperfusion injury, stunning, and familial hypertrophic cardiac myopathies.

The majority of human immunodeficiency virus (HIV)-seropositive patients develop bone marrow abnormalities associated with hematopoietic malfunction during the progression of disease. One important manifestation of HIV-associated hematopoietic dysfunction is that after myelosuppression, bone marrow recovery, a process known to be mediated in part by the production of stromal cell-derived hematopoietic growth factors, is impaired. We sought to test the hypothesis that bone marrow stromal cells are infected by HIV-1 in vivo and that production of certain stromal cell-derived hematopoietic growth factors is deficient as a consequence. In this report, we demonstrate that bone marrow microvascular endothelial cells (MVEC), a key element of the stroma, are the predominant cells infected by HIV (5% to 20%) in bone marrow stromal cultures obtained from 11 consecutive HIV-seropositive patients. Although HIV-infected stromal cultures enriched for MVEC constitutively express normal levels of interleukin (IL)-4, IL-6, granulocyte (G)-colony-stimulating factor (CSF), granulocyte-macrophage (GM)-CSF, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, and Steel factor, IL-1 alpha-induced release of IL-6 and G-CSF is significantly reduced in these cultures. These observations suggest that HIV infection of bone marrow MVEC reduces the capacity of hematopoietic stroma to respond to regulatory signals that normally augment blood cell production during periods of increased demand.

Publisher Summary This chapter describes regions on G-protein α subunits involved in interactions with receptors. The main model system to be employed is the light receptor rhodopsin and the rod G protein transducin (G t ). The visual signaling pathway is similar to that of other transduction cascades involving receptor–G-protein–effector coupling. Light activation of rhodopsin leads to the formation of metarhodopsin II (Meta II), which displays sites on the cytoplasmic surface for interaction with heterotrimeric G t . Meta II catalyzes a conformational change in the G t α subunit ( α t ) which opens its nucleotide binding pocket and decreases the affinity of guanosine-diphosphate (GDP). “Empty-pocket” G t displays transient high affinity for rhodopsin which normally is terminated when guanosine-5'-triphosphate (GTP) binds and causes a second conformational change, leading to decreased affinity of α t for both rhodopsin and βγ . In the absence of GTP, the molecular basis for the high-affinity interaction between receptor and G protein is examined in the chapter in great detail.

Heterotrimeric GTP-binding proteins (G proteins) regulate cellular activity by coupling to hormone or sensory receptors. Stimulated receptors catalyse the release of GDP from G protein alpha-subunits and GTP bound to the empty alpha-subunits provides signals that control effectors such as adenylyl cyclases, phosphodiesterases, phospholipases and ion channels. Three cytoplasmic loops of the activated receptor are thought to interact with three sites on the heterotrimeric G protein to provide high-affinity interaction and catalyse G-protein activation. The carboxyl terminus of the alpha-subunit is particularly important for interaction with the receptor. Here we study the structure of part of the active interface between the photon receptor rhodopsin and the G protein transducin, or Gt, using nuclear magnetic resonance. An 11-amino-acid peptide from the C terminus of the alpha-subunit of Gt (alpha t (340-350)) binds to rhodopsin and mimics the G protein in stabilizing its active form, metarhodopsin II. The peptide alpha t (340-350) binds to both excited and unexcited rhodopsin and conformational differences between the two bound forms suggest a mechanism for activation of G proteins by agonist-stimulated receptors. Insight into receptor-catalysed GDP release will have broad application because the GTP/GDP exchange and the intrinsic GTPase activity of GTP-binding proteins constitute a widespread regulatory mechanism.

In photoreceptor cells of vertebrates light activates a series of protein-protein interactions resulting in activation of a cGMP-phosphodiesterase (PDE). Interaction between the GTP-bound form of rod G-protein alpha-subunit (alpha t) and PDE inhibitory gamma-subunit (P gamma) is a key event for effector enzyme activation. This interaction has been studied using P gamma labeled with the fluorescent probe, lucifer yellow vinyl sulfone, at Cys-68 (P gamma LY) and sites of interaction on alpha t and P gamma have been investigated. Addition of alpha tGTP gamma S to P gamma LY produced a 3.2-fold increase in the fluorescence of P gamma LY. The Kd for alpha tGTP gamma S.P gamma LY interaction was 36 nM. Addition of 1 microM alpha tGDP had no effect, but in the presence of A1F4-, alpha tGDP increased P gamma LY fluorescence by 85%. When P gamma LY was reconstituted with P alpha beta to form fluorescent holo-PDE, alpha tGTP gamma S increased the fluorescence of holo-PDE with a K0.5 = 0.7 microM. Also, alpha tGTP gamma S stimulated the activity of this PDE over an identical range of concentrations with a similar K0.5 (0.6 microM). alpha tGTP gamma S enhanced the fluorescence of a COOH-terminal P gamma fragment, P gamma LY-46-87, as well (Kd = 1.5 microM). We demonstrate that an alpha t peptide, alpha t-293-314, which activated PDE (Rarick, H. M., Artemyev, N. O., and Hamm, H. E. (1992) Science 256, 1031-1033), mediates PDE activation by interacting with the P gamma-46-87 region. Peptide alpha t-293-314 bound to P gamma LY (K0.5 = 1.2 microM) as well as to the carboxyl-terminal P gamma fragment, P gamma LY-46-87 (K0.5 = 1.7 microM) as measured by fluorescence increase, while other alpha t peptides had no effect. A peptide from the P gamma central region, P gamma-24-46, blocked the interaction between alpha tGTP gamma S and P gamma LY. The Kd for alpha tGTP gamma S.P gamma-24-46 interaction was 0.7 microM. On the other hand, P gamma-24-46 had no effect on alpha t-293-314 interaction with P gamma LY. Our data suggest that there are at least two distinct sites of interaction between alpha tGTP gamma S and P gamma. The interaction between alpha t-293-314 and P gamma-46-87 is important for PDE activation.(ABSTRACT TRUNCATED AT 400 WORDS)

The heterotrimeric guanine nucleotide binding proteins (G proteins) are activated by sensory or hormone receptors. In turn, the G proteins activate effector proteins such as adenylyl cyclase, cyclic guanosine 3',5'-monophosphate phosphodiesterase (cGMP PDE), phospholipase C, and potassium and calcium ion channels by mechanisms that are poorly understood. A site on the alpha subunit of the G protein transducin (alpha t) has been identified that interacts with and activates cGMP phosphodiesterase, the effector enzyme in rod photoreceptors. A 22-amino acid peptide, corresponding to residues 293 to 314 from the COOH-terminal region of alpha t, fully mimicked alpha t and potently activated PDE. This region is adjacent to the receptor activation domain; thus, the alpha subunit of this G protein has a site for interaction with both its effector and receptor that maps near the COOH-terminus.

Patients with acquired immunodeficiency syndrome (AIDS)-related epidemic Kaposi's sarcoma generally respond well to cytotoxic chemotherapy. However, due to the associated myelosuppression, these patients are at risk for developing complicating infections that may affect survival. We therefore conducted a multi-center randomized clinical trial comparing single-agent against combination chemotherapy in advanced AIDS-related Kaposi's sarcoma. Low-dose chemotherapy was employed to evaluate its role in combination therapy for this disease and the toxicities associated with the lower intensity.Sixty-one patients with extensive mucocutaneous Kaposi's sarcoma or visceral involvement were randomized for treatment with low-dose Adriamycin (doxorubicin, 20 mg/m2) alone (31 cases) or in combination with bleomycin and vincristine (ABV) (30 cases). Patients were randomized within strata based on prognostic features associated with shorter survival in prior studies. Both treatment arms were evenly matched at study entry.Complete and partial tumor remissions were significantly higher with ABV (88%) than with Adriamycin alone (48%) (p = 0.004). The median survival was 9 months in both groups. Study entry criteria significantly associated with shorter survival included CD4 lymphocyte counts less than 100/mm3, hemoglobin level less than 10 g/dL, a history of constitutional symptoms, and a prior history of opportunistic infection(s). Toxicities were similar in both arms, and the regimens were well tolerated. Neutropenia (granulocyte count less than 1,000/mm3) occurred in 34% of patients receiving Adriamycin alone and in 52% of patients receiving ABV and was progressive in successive courses of chemotherapy in both treatment arms. The development of AIDS-defined opportunistic infections was relatively infrequent during therapy (14%).Low-dose ABV is an effective chemotherapy regimen for the treatment of extensive Kaposi's sarcoma. ABV chemotherapy is associated with significantly higher responses than Adriamycin alone and with acceptable toxicity.

We used an endoscopic method of quantification to evaluate the response of symptomatic gastrointestinal Kaposi's sarcoma (KS) prospectively in seven patients with acquired immune deficiency syndrome (AIDS) who were participating in chemotherapy trials for extensive cutaneous KS. The sums of the diameters of KS lesions in the esophagus, stomach, duodenum, and distal colon were used as a measure of extent of disease. Intravenous therapy [adriamycin/bleomycin/vincristine (N = 5), adriamycin (N = 1), or bleomycin/vincristine (N = 1)] was given every 2 wk for a mean of six cycles. Five of seven patients (71%) had a cutaneous response, whereas 9/15 (60%) gastrointestinal sites showed a remission. Sites of complete response all had an initial sum of lesion diameters less than or equal to 30 mm. Five of five patients with duodenal KS responded (3/5 complete), whereas just two partial responses were seen in five patients with gastric KS (4/5 with duodenal KS had sums of diameters less than or equal to 20 mm, whereas 4/5 with gastric KS had sums greater than or equal to 150 mm). Symptoms (abdominal pain, nausea/vomiting, hematemesis, diarrhea) resolved in all patients within two cycles of therapy. In summary: 1) the response rate of gastrointestinal KS to chemotherapy is similar to that of cutaneous KS; 2) the best response is seen in patients with less extensive disease and duodenal involvement; and 3) symptoms of gastrointestinal KS respond to chemotherapy even if the KS lesions do not resolve.

RATIONALE AND OBJECTIVES MRI was used for the in vivo evaluation of unilateral hypoxic-ischemic brain injury and the evaluation of MK-801 in the neonatal rat. METHODS T2-weighted scans were obtained during the acute phase of HI injury and 3 months later. Histology was performed to correlate MRI signal changes with pathology. Finally, the effectiveness of MK-801 to limit brain injury was regionally assessed in vivo using T2-weighted MRI. RESULTS Injury visualized by MRI at 72 hours after hypoxia correlated strongly with histopathologic analysis. Transient injury was identified. MK-801 significantly reduced the lesion extent at the level of the hippocampus. Patterns of unilateral versus bilateral neonatal brain injury were found to differ. CONCLUSIONS The study demonstrates unique patterns of brain injury not seen in adult animal hypoxia-ischemia studies, and the sensitivity of the corpus callosum to hypoxia-ischemia. MK-801, although neuroprotective, did not offer any selective neuroprotective benefit.

Developmental Changes in the Regulation of Contractions in Human Fetal Cardiac Myocytes. † 100

Eleven heterosexual patients (nine women, two men) without classic risk factors for development of acquired immunodeficiency syndrome (AIDS) were seen between March 1983, and April 1985, and diagnosed as having AIDS (four), persistent, generalized lymphadenopathy (PGL) (four), or asymptomatic human T-cell lymphotropic virus type III (HTLV-III) carrier state (three). The clinical presentations and course of those with AIDS or PGL were similar to those reported in homosexual men with AIDS or PGL, with reversed T4/T8 ratio, and the presence of antibody to HTLV-III. Asymptomatic carriers had normal T4/T8 ratios, had an absence of HTLV-III antibodies, but had HTLV-III virus cultured from blood. We conclude that the heterosexual population, with or without history of sexual exposure to individuals at risk for AIDS, may develop a wide range of clinical manifestations secondary to HTLV-III, varying from AIDS to the asymptomatic carrier state.

Primary central nervous system (CNS) lymphoma is one of the clinical presentations of the acquired immune deficiency syndrome (AIDS). Ten patients had biopsy-proven high-grade lymphomas that were confirmed by further staging as limited to the CNS. All ten patients received cranial irradiation (total dose, 2200 to 5000 cGy). Six patients demonstrated complete response (CR) of the intracranial masses at the time of repeat computed tomography (CT) scan, whereas one attained a partial response (PR). Two of the CR patients died of multiple opportunistic infections, two experienced relapse of lymphoma, and died at 7 and 16 months from diagnosis, and two were alive without evidence of disease at 8 and 14 months from diagnosis. The median survival of the whole group was 5.5 months (range, 2 to 16 months). Patients with AIDS-related primary CNS lymphoma may respond to radiation treatment; however, response duration is usually short, and survival is influenced by refractory disease or systemic opportunistic infections.