Validity, reliability, and transcultural adaptations of the Bayley Scales of Infant and Toddler Development (BSID-III-NL) for children in Suriname.

BACKGROUND: A valid and reliable measure of infant neurodevelopment is needed in Suriname, South America. The Bayley Scales of Infant and Toddler Development, 3rd edition (BSID-III), was created for evaluation of United States infants and toddlers and subsequently validated for use in Dutch speaking infants of the Netherlands (BSID-III-NL). Given that Suriname was a previous Dutch colony and Dutch remains the national language of Suriname, this study sought to evaluate the psychometric properties of the BSID-III-NL in Suriname. AIMS: Given that the cultural context differs between Suriname, the United States, and the Netherlands, the aims of this study were to determine if any cultural adaptations of the BSID-III-NL were needed for Surinamese infants and to evaluate its psychometric properties. METHODS: Two hundred and ninety-nine infants between the ages of 10 to 26 months were assessed in three geographic regions of Suriname between May 2018 and July 2019. Minor adaptations to the BSID-III-NL imagery were made based on the input of Surinamese pediatricians and neuropsychologists who were also involved in the administration of the BSID-III-NL in Suriname. Raw scores were collected for the cognitive, communicative, and motor subscales of the BSID-III-NL. Factor structure was evaluated with exploratory factor analysis and cluster analysis, and reliability of internal consistency was assessed using Cronbach's alpha coefficient for each subscale. RESULTS: Content validity was endorsed by pediatricians and neuropsychologists in Suriname who participated in the administration of the BSID-III-NL. Construct validity was demonstrated through agreement of items from cluster analysis where at least 81.56% of all variability was explained by clustering with correct or incorrect responses and mean raw scores in subscales increased with age group. Cronbach's alpha coefficient was above 0.77 for all subscales. CONCLUSIONS: This internationally validated developmental measure was found to be valid and reliable in assessing neurodevelopment of infants in Suriname.

Myosin light chain kinase binding to a unique site on F-actin revealed by three-dimensional image reconstruction.

Ca2+-calmodulin-dependent phosphorylation of myosin regulatory light chains by the catalytic COOH-terminal half of myosin light chain kinase (MLCK) activates myosin II in smooth and nonmuscle cells. In addition, MLCK binds to thin filaments in situ and F-actin in vitro via a specific repeat motif in its NH2 terminus at a stoichiometry of one MLCK per three actin monomers. We have investigated the structural basis of MLCK-actin interactions by negative staining and helical reconstruction. F-actin was decorated with a peptide containing the NH2-terminal 147 residues of MLCK (MLCK-147) that binds to F-actin with high affinity. MLCK-147 caused formation of F-actin rafts, and single filaments within rafts were used for structural analysis. Three-dimensional reconstructions showed MLCK density on the extreme periphery of subdomain-1 of each actin monomer forming a bridge to the periphery of subdomain-4 of the azimuthally adjacent actin. Fitting the reconstruction to the atomic model of F-actin revealed interaction of MLCK-147 close to the COOH terminus of the first actin and near residues 228-232 of the second. This unique location enables MLCK to bind to actin without interfering with the binding of any other key actin-binding proteins, including myosin, tropomyosin, caldesmon, and calponin.

Hepatic secretion of phospholipid vesicles in the mouse critically depends on mdr2 or MDR3 P-glycoprotein expression. Visualization by electron microscopy.

Hepatocellular secretion of bile salts into the biliary space induces phospholipid and cholesterol secretion, but the mechanism for integrated lipid secretion is poorly understood. Knockout mice unable to make the canalicular membrane mdr2 P-glycoprotein exhibit normal rates of bile salt secretion, yet are virtually incapable of secreting biliary phospholipid and cholesterol. As the mdr2 P-glycoprotein is thought to mediate transmembrane movement of phospholipid molecules, this mouse model was used to examine the mechanism for biliary phospholipid secretion. In wild-type mdr2 (+/+) mice, ultrarapid cryofixation of livers in situ revealed abundant unilamellar lipid vesicles within bile canalicular lumina. Although 74% of vesicles were adherent to the external aspect of the canalicular plasma membrane, bilayer exocytosis was not observed. Vesicle numbers in mdr2 (+/-) and (-/-) mice were 55 and 12% of wild-type levels, respectively. In a strain of mdr2 (-/-) mice which had been "rescued" by heterozygous genomic insertion of the MDR3 gene, the human homologue of the murine mdr2 gene, vesicle numbers returned to 95% of wild-type levels. Our findings indicate that biliary phospholipid is secreted as vesicles by a process largely dependent on the action of the murine mdr2 P-glycoprotein or human MDR3 P-glycoprotein. We conclude that mdr2-mediated phospholipid translocation from the internal to external hemileaflet of the canalicular membrane permits exovesiculation of the external hemileaflet, a vesiculation process promoted by the detergent environment of the bile canalicular lumen.

Differential screening of a human chromosome 3 library identifies hepatocyte growth factor-like/macrophage-stimulating protein and its receptor in injured lung. Possible implications for neuroendocrine cell survival.

Transient pulmonary neuroendocrine cell hyperplasia and non-neuroendocrine lung tumors develop in nitrosaminetreated hamsters, which we hypothesized might modulate epithelial cell phenotype by expressing gene(s) homologous to human chromosome 3p gene(s) deleted in small cell carcinoma of the lung (SCLC). We differentially screened a chromosome 3 library using nitrosamine-treated versus normal hamster lung cDNAs and identified hepatocyte growth factor-like/macrophage-stimulating protein (HGFL/MSP) in injured lung. HGFL/MSP mRNA is low to undetectable in human SCLC and carcinoid tumors, but the HGFL/MSP tyrosine kinase receptor, RON, is present and functional on many of these neuroendocrine tumors. In H835, a pulmonary carcinoid cell line, and H187, a SCLC cell line, HGFL/ MSP induced adhesion/flattening and apoptosis. Using viable cell counts to assess proliferation after 14 d of treatment with HGFL/MSP, there is growth inhibition of H835 but not H187. Nitrosamine-treated hamsters also demonstrate pulmonary neuroendocrine cell apoptosis in situ during the same time period as expression of the endogenous HGFL/ MSP gene, immediately preceding the spontaneous regression of neuroendocrine cell hyperplasia. These observations suggest that HGFL/MSP might regulate neuroendocrine cell survival during preneoplastic lung injury, which could influence the ultimate tumor cell phenotype.

A phase I-II trial of carboplatin and 5-fluorouracil combination chemotherapy in advanced carcinoma of the head and neck.

Twenty-nine patients with recurrent or advanced, incurable head and neck cancer were entered into a phase I-II trial of carboplatin in combination with 5-fluorouracil (5-FU), 1,000 mg/m2/d continuous intravenous (IV) infusion for five days every 28 days. The initial dose of carboplatin was 300 mg/m2 for patients with Karnofsky performance scores greater than or equal to 70%, and 240 mg/m2 for patients with scores of 50% to 60%. Subsequent doses were modified to achieve grade 2 myelo-suppression: WBC, 2,000 to 2,999 cells/microL; granulocytes, 1,000 to 1,499 cells/microL; and platelets, 50,000 to 75,000 cells/microL. Dose levels were 180, 240, 300, 360, and 420 mg/m2. Twenty-eight patients had squamous-cell cancers and one had an adenoid cystic carcinoma of the parotid. There were 26 patients with recurrent disease; 22 had received prior RT; only two had received other chemotherapy immediately before study entry. Three patients had newly diagnosed incurable stage IV disease. The median performance status was 80% (range, 60% to 90%). All patients had objectively measurable disease, and 28 were evaluable for response. There were three complete responses (CRs) and ten partial responses (PRs) (48% CR and PR); the median duration of response was 4.7 months (range, 1.5 to 15+ months). Dose-limiting toxicities were granulocytopenia, thrombocytopenia, and stomatitis. Prolonged myelosuppression delayed retreatment in eight patients and delayed 19 of 107 (18%) courses. Stomatitis occurred in 61% and diarrhea in 29%. 5-FU dosage was decreased in ten patients (36%) for grade 2 or greater stomatitis or diarrhea. Mild to moderate nausea and vomiting occurred in 66% of patient trials in which no pretreatment antiemetics were administered. Other toxicities included phlebitis from 5-FU in 71%, skin toxicity in 11%, mild alopecia in 25%, and fatigue in 54% of patients. Nephrotoxicity (creatinine greater than 2.0 mg/dL) occurred in one patient. The dose of carboplatin resulting in grade 2 toxicity was 180 mg/m2 in one patient, 240 mg/m2 in one, 300 mg/m2 in seven, 360 mg/m2 in ten, and 420 mg/m2 in one. Based on these results, we recommend a starting dose of carboplatin, 300 mg/m2, in combination with five days of continuous infusion 5-FU. In this dose and schedule, this combination was well tolerated and demonstrated antitumor activity in head and neck cancer. To confirm these promising results, a Southwest Oncology Group prospective randomized trial is in progress comparing carboplatin and 5-FU, cisplatin and 5-FU, and standard-dose weekly methotrexate in recurrent-disease patients.

Coiled-coil packing in spermine-induced tropomyosin crystals. A comparative study of three forms.

Electron microscope images of highly ordered spermine-induced microcrystals of tropomyosin have been analyzed to determine the packing of the molecular filaments. Negatively stained microcrystals terminate in a distinctive "double fringe", which reveals the location of the molecular ends. This information, together with the symmetry of the structure in projection, shows that the microcrystals can be accounted for by a packing scheme of four layers of molecules in the unit cell. Knowing the position of the symmetry elements relating the layers then allows the three-dimensional space group of the microcrystals to be established as C222(1). Using cryo-electron microscopy and simulation studies, the run of the filaments and their packing in the C222(1) form have been shown to be related to those in the spermine-induced C2 crystal of tropomyosin whose structure has been solved to 9 A by X-ray crystallography. This result allows us to infer the location of the molecular ends in the C2 crystal as well, and this inference has been confirmed by analysis of thin sections of the C2 crystal. The C222(1) microcrystal has also been shown to be closely related to the classical divalent cation tropomyosin paracrystal. Based on knowledge of the molecular packing in the divalent cation paracrystal, the polarity of the molecules has been deduced in the other two crystal forms. The tropomyosin filament packing in all these forms may be accounted for by coiled-coil close packing and specific cationic bridging of negatively charged zones on the molecule. Taken together the results reveal a hierarchy of interactions in these close-packed crystalline forms, whose principles may apply to the packing in other fibrous proteins. This study also shows the usefulness of co-ordinating results from cryo-electron microscopy with negative staining in the structure analysis of such ordered arrays, and how these findings can complement the results of low resolution X-ray crystallographic studies.

Structure of tropomyosin at 9 angstroms resolution.

We have used molecular replacement followed by a highly parameterized refinement to determine the structure of tropomyosin crystals to a resolution to 9 A. The shape, coiled-coil structure and interactions of the molecules in the crystals have been determined. These crystals have C2 symmetry with a = 259.7 A, b = 55.3 A, c = 135.6 A and beta = 97.2 degrees. Because of the unusual distribution of intensity in X-ray diffraction patterns from these crystals, it was possible to solve the rotation problem by inspection of qualitative aspects of the diffraction data and to define unequivocally the general alignment of the molecules along the (332) and (3-32) directions of the unit cell. The translation function was then solved by a direct search procedure, while electron microscopy of a related crystal form indicated the probable location of molecular ends in the asymmetric unit, as well as the anti-parallel arrangement. The structural model we have obtained is much clearer than that obtained previously with crystals of extraordinarily high solvent content and shows the two alpha-helices of the coiled coil over most of the length of the molecules and establishes the coiled-coil pitch at 140(+/- 10) A. Moreover, the precise value of the coiled-coil pitch varies along the molecule, probably in response to local variations in the amino acid sequence, which we have determined by sequencing the appropriate cDNA. The crystals are constructed from layers of tropomyosin filaments. There are two molecules in the crystallographic asymmetric unit and the molecules within a layer are bent into an approximately sinusoidal profile. Molecules in consecutive layers in the crystal lie at an angle relative to one another as found in crystalline arrays of actin and myosin rod. There are three classes of interactions between tropomyosin molecules in the spermine-induced crystals and these give some insights into the molecular interactions between coiled-coil molecules that may have implications for assemblies such as muscle thick filaments and intermediate filaments. In interactions within a layer, the geometry of coiled-coil contacts is retained, whereas in contacts between molecules in adjacent layers the coiled-coil geometry varies and these interactions instead appear to be dominated by the repeating pattern of charged zones along the molecule.

Tropomyosin and actin isoforms modulate the localization of tropomyosin strands on actin filaments.

Tropomyosin is present in virtually all eucaryotic cells, where it functions to modulate actin-myosin interaction and to stabilize actin filament structure. In striated muscle, tropomyosin regulates contractility by sterically blocking myosin-binding sites on actin in the relaxed state. On activation, tropomyosin moves away from these sites in two steps, one induced by Ca(2+) binding to troponin and a second by the binding of myosin to actin. In smooth muscle and non-muscle cells, where troponin is absent, the precise role and structural dynamics of tropomyosin on actin are poorly understood. Here, the location of tropomyosin on F-actin filaments free of troponin and other actin-binding proteins was determined to better understand the structural basis of its functioning in muscle and non-muscle cells. Using electron microscopy and three-dimensional image reconstruction, the association of a diverse set of wild-type and mutant actin and tropomyosin isoforms, from both muscle and non-muscle sources, was investigated. Tropomyosin position on actin appeared to be defined by two sets of binding interactions and tropomyosin localized on either the inner or the outer domain of actin, depending on the specific actin or tropomyosin isoform examined. Since these equilibrium positions depended on minor amino acid sequence differences among isoforms, we conclude that the energy barrier between thin filament states is small. Our results imply that, in striated muscles, troponin and myosin serve to stabilize tropomyosin in inhibitory and activating states, respectively. In addition, they are consistent with tropomyosin-dependent cooperative switching on and off of actomyosin-based motility. Finally, the locations of tropomyosin that we have determined suggest the possibility of significant competition between tropomyosin and other cellular actin-binding proteins. Based on these results, we present a general framework for tropomyosin modulation of motility and cytoskeletal modelling.

Double-blind randomized study comparing amoxicillin and erythromycin for the treatment of Chlamydia trachomatis in pregnancy.

OBJECTIVE: To compare the efficacy and patient tolerance of amoxicillin to that of erythromycin in the treatment of lower genital tract chlamydia infections during pregnancy. METHODS: A double-blind, randomized study was conducted comparing oral amoxicillin 500 mg three times daily versus oral erythromycin 500 mg four times daily for 7 days. One hundred forty-three women with positive cervical cultures for chlamydia at less than 36 weeks' gestation were enrolled. A test-of-cure culture was obtained 4 weeks after entry into the study and side effects were assessed. Success of the regimen was defined as completing the course of medication and having a negative test-of-cure culture. RESULTS: Thirty of the 65 women in the erythromycin group (46.1%) developed symptoms while taking the medication and 15 of them were unable to continue treatment (23.1%). In contrast, five of the 65 women (7.7%) in the amoxicillin group became symptomatic, with only one of these patients intolerant of the side effects (1.5%) (P < .001). Of the 50 patients in the erythromycin group who were able to complete their course of medication, only three had a positive test of cure (6.0%). In comparison, nine of the 64 patients (14.1%) taking amoxicillin who completed their course had positive cultures at test of cure. This difference was not statistically significant (P = .14). Forty-seven of the 65 patients (72.3%) in the erythromycin group successfully completed their regimen, compared to 55 of the 65 women (84.6%) in the amoxicillin group. This difference was not statistically significant. CONCLUSIONS: These findings suggest that amoxicillin is a reasonable alternative for the treatment of chlamydia in pregnant patients intolerant to erythromycin. The incidence of side effects and intolerance to therapy for amoxicillin are less than those for erythromycin.

High-dose cisplatin in advanced head and neck cancer.

In 22 patients with advanced squamous cell carcinoma of the head and neck we evaluated the efficacy and toxicity of 200 mg/m2 cisplatin administered in 3% NaCl with vigorous hydration. Six patients had previously untreated stage IV disease and 16 patients had recurrent disease, including eight with prior chemotherapy including low-dose cisplatin and carboplatin. Cisplatin was administered as a brief infusion, either 40 mg/m2/day X 5 or 50 mg/m2/day X4, every 28 days. Objective responses were observed in 16 of 22 (73%) patients, including 5 of 6 (83%) previously untreated patients and 11 of 16 (69%) patients with recurrent disease. This included two complete responses, one confirmed pathologically. Fifty-seven courses of drug were administered and toxicity was monitored with serial creatinine clearance determinations, audiograms, and sensorimotor exams. Neuropathy and ototoxicity were dose-limiting and led to the stopping of treatment in 12 of the 16 responders after one to four courses (median three courses). Only two responding patients continued treatment until disease progression occurred at 3 and 4 months after achieving maximum response. Acute, transient nephrotoxicity occurred in four patients; two were retreated. Moderate myelosuppression occurred in all patients but was not treatment-limiting. For most patients the maximally tolerated number of courses was three. The median survival time was 33.5 weeks for recurrent disease patients, 108 weeks for newly diagnosed patients. This regimen is not recommended for the palliation of recurrent disease. However, the very high response rate suggests that high-dose cisplatin may have a useful role in induction or adjuvant chemotherapy regimens.

Tamoxifen therapy in patients with recurrent laryngeal squamous carcinoma.

Twelve patients with recurrent, advanced laryngeal carcinoma were treated with tamoxifen hormonal therapy. Rationale was based on previous in vitro data identifying estrogen receptors and progesterone receptors in some laryngeal carcinoma cell lines. Four patients received tamoxifen, 10 to 20 mg by mouth twice a day; eight received 40 mg by mouth four times a day. The drug was well tolerated at all dose levels. There were no clinical responses. Two patients' tumor tissue was assayed for estrogen and progesterone receptors. One was negative for both, and the other was indeterminate for estrogen receptors and negative for progesterone receptors. A review of literature and a discussion of the possible reasons for the negative results are presented.

Ultrafine particles in human lung macrophages.

As knowledge about size dependency of particle toxicity continues to grow, attention has been focused on ultrafine particles (i.e., < 0.1 microm in diameter). In recent studies with rats, investigators learned that ultrafine particles likely have greater pulmonary toxicity than larger particles, and it is possible that exposure to, and accumulation of, these particles in the human lung may be associated with adverse respiratory health effects. As part of an ongoing study, the authors performed bronchoalveolar lavage in 14 healthy current nonsmokers to investigate the extent to which ultrafine particles were present in lung macrophages. In addition, 10 of the 14 subjects performed pulmonary function tests. Eleven of the 14 subjects were utility workers, and 3 were nonmaintenance employees of a university. The authors used a Zeiss CEM902 electron microscope to study macrophages isolated from bronchoalveolar lavage fluid. Morphometric quantification revealed ultrafine particles in lung macrophages of all 14 volunteers; the average number of ultrafine particles/microm3 cytoplasm per cell (UFavg) ranged from 34 to 231 (mean = 95, standard deviation = 54). Regression analysis showed that the UFavg was associated inversely with percent predicted forced expiratory volume in 1 second (FEV1.0) (beta = -1.2 percent predicted FEV1.0/10 ultrafine particles x microm3 cytoplasm per cell [standard error = 0.45, p = .031). The demonstration of ultrafine particles in all 14 subjects, independent of occupational exposure, suggests that there is environmental exposure to ultrafine particles. The negative association between the number of ultrafine particles and ventilatory function demonstrates a need for further investigation into the pulmonary health effects of ultrafine particles.

Chronic bronchitis alters the pattern of aerosol deposition in the lung.

Knowledge of the local and regional doses of inhaled particulates is crucial for inhalation therapy and for understanding the progression of pulmonary disease. We studied the deposition pattern of radioactively tagged particles in rats with chronic bronchitis. Rats were exposed to sulfur dioxide (SO2; 236 +/- 14 ppm) for 5 h/d, 5 d/wk for 7 wk to produce chronic bronchitis (CB). Control rats were exposed to room air. The control animals gained 85% more weight over the 7-wk period than did the CB rats. Five control and five CB rats were then exposed for 30 min to an insoluble 99mTc-labeled aerosol. The animals were killed within 5 min after the exposure period. The lungs were excised, dried at total lung capacity (TLC), and sliced into 1 mm sections. The distribution of the radiolabeled particles retained in the lungs was determined in two ways. First, autoradiographs were made of the distribution of the radioactivity throughout a lung slice. Autoradiographs were quantified by image analysis to determine the amount of radioactivity (relative density of the film) associated with airway versus parenchyma (ratio of airway to parenchyma density). The lung slices were then dissected into pieces, the weight and radioactivity content of each piece was measured, and its evenness index (EI) was calculated. This type of analysis enables the homogeneity of particle deposition throughout the lungs to be assessed. If deposition were totally uniform, the average EI would be 1.0 with an SD = 0. The total amount of radioactivity retained in the lungs was similar in control and CB rats.(ABSTRACT TRUNCATED AT 250 WORDS)

An actin subdomain 2 mutation that impairs thin filament regulation by troponin and tropomyosin.

Striated muscle thin filaments adopt different quaternary structures, depending upon calcium binding to troponin and myosin binding to actin. Modification of actin subdomain 2 alters troponin-tropomyosin-mediated regulation, suggesting that this region of actin may contain important protein-protein interaction sites. We used yeast actin mutant D56A/E57A to examine this issue. The mutation increased the affinity of tropomyosin for actin 3-fold. The addition of Ca(2+) to mutant actin filaments containing troponin-tropomyosin produced little increase in the thin filament-myosin S1 MgATPase rate. Despite this, three-dimensional reconstruction of electron microscope images of filaments in the presence of troponin and Ca(2+) showed tropomyosin to be in a position similar to that found for muscle actin filaments, where most of the myosin binding site is exposed. Troponin-tropomyosin bound with comparable affinity to mutant and wild type actin in the absence and presence of calcium, and in the presence of myosin S1, tropomyosin bound very tightly to both types of actin. The mutation decreased actin-myosin S1 affinity 13-fold in the presence of troponin-tropomyosin and 2.6-fold in the absence of the regulatory proteins. The results suggest the importance of negatively charged actin subdomain 2 residues 56 and 57 for myosin binding to actin, for tropomyosin-actin interactions, and for regulatory conformational changes in the actin-troponin-tropomyosin complex.

Imaging biliary lipid secretion in the rat: ultrastructural evidence for vesiculation of the hepatocyte canalicular membrane.

Physical-chemical and biological studies of hepatic bile suggest that biliary phospholipid molecules are secreted as unilamellar vesicles. Systematic ultrastructural studies of bile canaliculi were undertaken to visualize this event. Liver tissue was obtained from normal adult male rats (control), from bile salt-depleted rats (by overnight biliary diversion), and from depleted rats infused intravenously with a hydrophilic-hydrophobic congener series of common taurine-conjugated bile salts. Livers were fixed in situ either by modified chemical methods or by ultrarapid cryofixation. In control rats, chemical fixation revealed unilamellar vesicles 63 +/- 17 (+/- SD) nm in diameter, mostly free within canalicular lumena. Vesicles were infrequent in canaliculi of bile salt-depleted rats, but were present in canaliculi of rats infused with taurocholate. In cryofixed liver tissue, vesicles 67 +/- 13 nm in diameter were observed in canaliculi of control rats and bile-salt depleted rats infused with common bile salts. The majority of these vesicles were affixed to the luminal side of the canalicular membrane. The average number of vesicles per bile canaliculus was in agreement with that estimated on the basis of biliary phospholipid secretion rates, mean vesicle size, and area of close-packed phosphatidylcholine molecules. By immunoelectron microscopy, canalicular vesicles were free of actin and of a 100 kDa canalicular membrane protein. We conclude that biliary phospholipid molecules are secreted from hepatocytes into bile canalicular lumena as unilamellar vesicles approximately 63-67 nm in average diameter. We postulate that this secretion mechanism involves lumenal bile salt-induced vesiculation of lipid microdomains in the exoplasmic hemileaflet of the canalicular membrane.