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Biomedical subjects

A Ross

Publications and source records attributed to A Ross.

At least 91 records · Page 5Linked to original sources
PubMed1998

Initiating the first DTP vaccination age-appropriately: a model for understanding vaccination coverage.

OBJECTIVE: Our earlier research found that the strongest predictor of not being up to date on the full series of immunizations by 24 months is failure to receive the first diphtheria vaccine and tetanus toxoid and pertussis vaccine (DTP1) on time. To learn more about the relationship between successful vaccination during the DTP1 age-appropriate (DTP1-AA) period (between 42 and 92 days of life, inclusive) and an infant's early visit to the physician (before 42 days of life), we quantified children's progression through a sequence of provider visits and outcomes. DESIGN: This study analyzed data from 426 children living in the 57 poorest census tracts in Baltimore. For each DTP1-AA visit, we calculated the percentage of times a DTP1-AA vaccination, provider missed opportunity, or deferral for a valid contraindication occurred. Relative and attributable risks were computed to assess associations between DTP1-AA vaccination and early visits and missed opportunities. RESULTS: We found the following: 1) Children who made a visit before 42 days of life were more than twice as likely to receive a DTP1-AA vaccination; 2) the missed opportunity rate for children who did not make an early visit was approximately twice that of the early-visit group; and 3) well visits were more likely to result in DTP1-AA immunization than sick visits. Attributable risk calculations show that DTP1-AA vaccination rates could be increased in this population by one third if all infants had an early visit. CONCLUSIONS: Early in-office visits seem to make DTP1-AA vaccination more likely. These rates may be amenable to intervention by increasing early visits and reducing DTP1-AA missed opportunities. Introduction of the hepatitis B vaccine to the recommended series may place more emphasis on early visits and result in increased DTP1-AA rates and, ultimately, higher vaccination coverage rates.

Age Factors↗
PubMed1998

Effect of compensation method on the behavior of primary care physicians in managed care organizations: evidence from interviews with physicians and medical leaders in Washington State.

The perceived relationship between primary care physician compensation and utilization of medical services in medical groups affiliated with one or more among six managed care organizations in the state of Washington was examined. Representatives from 67 medical group practices completed a survey designed to determine the organizational arrangements and norms that influence primary care practice and to provide information on how groups translate the payments they receive from health plans into individual physician compensation. Semistructured interviews with 72 individual key informants from 31 of the 67 groups were conducted to ascertain how compensation method affects physician practice. A team of raters read the transcripts and identified key themes that emerged from the interviews. The themes generated from the key informant interviews fell into three broad categories. The first was self-selection and satisfaction. Compensation method was a key factor for physicians in deciding where to practice. Physicians' satisfaction with compensation method was high in part because they chose compensation methods that fit with their practice styles and lifestyles. Second, compensation drives production. Physician production, particularly the number of patients seen, was believed to be strongly influenced by compensation method, whereas utilization of ancillary services, patient outcomes, and satisfaction are seen as much less likely to be influenced. The third theme involved future changes in compensation methods. Medical leaders, administrators, and primary care physicians in several groups indicated that they expected changes in the current compensation methods in the near future in the direction of incentive-based methods. The responses revealed in interviews with physicians and administrative leaders underscored the critical role compensation arrangements play in driving physician satisfaction and behavior.

Administrative Personnel↗
PubMed1997

Skin carcinogenicity of condensed asphalt roofing fumes and their fractions following dermal application to mice.

Condensed roofing asphalt fumes, generated at 316 degrees C, were collected by cold trap condensation and fractionated by preparative high performance liquid chromatography. Chemical classes in each of the fractions (A-E) were identified by gas chromatography/mass spectroscopy. The fractions, various combinations of fractions, the raw and heated asphalt, the neat asphalt fume and the reconstituted asphalt were tested for carcinogenicity, and three fractions were tested for cocarcinogenicity and tumor promotion with benzo[a]pyrene (BaP). The skin application carcinogenesis bioassay was conducted by twice weekly application of test materials in 0.05 ml of acetone/cyclohexane (1:1) for 104 weeks to 40 groups of male C3H/HeJ mice (30/group). Fractions were applied at a mass in proportion to their amount in the neat asphalt fumes. In addition, the neat asphalt fume was tested on Sencar mice to determine if this strain was more susceptible to the carcinogenic effects of the fumes. Condensed neat asphalt fumes produced similar and statistically significant increased tumor yields of papillomas and carcinomas in both strains as compared to respective vehicle controls. Recombination of all fractions resulted in a tumor response similar to neat asphalt fumes. Among individual fractions, C was most potent, followed by B. The other single fractions were without significant tumorigenic activity. Combinations containing fractions B and C were most active among the mixtures that were assayed and no evidence of enhancement of tumorigenesis in the mixtures was found. No significant cocarcinogenic or tumor promoting activity was observed with fractions A, D, or E and BaP. Raw unheated asphalt produced a few tumors in C3H mice, but no tumors were seen when raw asphalt heated to 316 degrees C, with the fumes permitted to escape, was applied.

Animals↗
PubMed1997

Expression of RBM in the nuclei of human germ cells is dependent on a critical region of the Y chromosome long arm.

The association of abnormal spermatogenesis in men with Y chromosome deletions suggests that genes important for spermatogenesis have been removed from these individuals. Recently, genes encoding two putative RNA-binding proteins (RBM and DAZ/SPGY) have been mapped to two different regions of the human Y chromosome. Both of these genes encode proteins that contain a single RNA recognition motif and a (different) internally repeating sequence. Y-linked RBM homologues are found in all mammalian species. We have raised an antiserum to RBM and used it to show that RBM is a nuclear protein expressed in fetal, prepubertal, and adult male germ cells. The distribution of RBM protein in the adult correlates with the pattern of transcriptional activity in spermatogenesis, suggesting that RBM is involved in the nuclear metabolism of newly synthesized RNA. RBM sequences are found on both arms of the Y chromosome making genotype-phenotype correlations difficult for this gene family. To address the location of the functional genes and the consequences of their deletion, we examined a panel of men with Y chromosome deletions and known testicular pathologies using this antiserum. This approach enabled us to map a region of the Y chromosome essential for RBM expression. In the absence of detectable RBM expression we see stages of germ cell development up to early meiosis, but not past this point into the haploid phase of spermatogenesis.

Adult↗
PubMed1997

Are immunizations an incentive for well-child visits?

OBJECTIVE: To assess the beliefs of parents and the visit patterns of their children to determine whether immunizations act as an incentive to use well-child care. DESIGN AND METHODS: Medical record audits provided data on immunizations and well-child visits. Two questions from a parent interview were used to identify 4 groups of parents: (1) motivated and (2) unmotivated to keep a well-child care appointment regardless of whether immunizations are scheduled, (3) vaccine-motivated and (4) checkup-motivated (parents who were influenced negatively by the prospect of receiving vaccinations). The percentage of children with a visit at each age window for well-child visits and the percentage up-to-date for their immunizations at given ages were compared across the 4 groups. The 4 groups were also compared for other parental attitudes about immunizations and well-child visits, and on sociodemographic and access characteristics. RESULTS: Most (73.3%) of the 502 parents surveyed were classified as motivated and 5% as unmotivated to keep a well-child care appointment regardless of whether an immunization was scheduled. Only 18.3% were categorized as vaccine-motivated and 3.4% as checkup-motivated. For all 4 groups, there was no discernible difference in attendance between immunization and nonimmunization visits. Attendance in the windows for well-child visits and percentage of children up-to-date on immunizations declined with increasing age. CONCLUSIONS: In this inner-city population, attendance patterns at visits did not support the incentive hypothesis. This finding should reassure clinicians that providing immunizations outside of regular well-child care visits will not necessarily decrease attendance at visits for well-child care.

Baltimore↗
PubMed1997

Disruption of PAX6 function in mice homozygous for the Pax6Sey-1Neu mutation produces abnormalities in the early development and regionalization of the diencephalon.

Pax6 expression in the diencephalon of the mouse embryo is restricted both antero-posteriorly and dorso-ventrally, with changes in level occurring at prosomere boundaries. Small eye (Pax6Sey-1Neu) mice homozygous for Pax6 mutations have multiple defects in early forebrain development. In the diencephalon of Pax6Sey-1Neu/Pax6Sey-1Neu mice there is an apparent enlargement of the zona limitans (the boundary region between prosomeres p2 and p3), and a blurring of the p1-p2 boundary. PAX6 function is also required for the normal development of the posterior commissure at the midbrain-p1 boundary. In the posterior diencephalon PAX6 appears to regulate its own transcription, and that of Wnt7b. In p2 and p3, ventral markers are expressed more dorsally than normal, and this is accompanied in p3 by a reduction in the size of the zona incerta. Thus, PAX6 is essential for the normal development and regionalization of the diencephalon.

Animals↗
PubMed1997

Quartz balance DNA sensor.

Single-strand DNA-containing thin films were deposited onto quartz oscillators by the Langmuir-Blodgett technique towards the realization of a device capable of sensing the presence of the complementary DNA sequences which hybridize with the immobilized ones. DNA, once complexed with aliphatic amines, appears as a monolayer in a single-stranded form by X-ray small angle scattering. A quartz nanobalance is then utilized to monitor mass increment related to specific hybridization with a complementary DNA probe. The crystal quartz nanobalance, capable of high sensitivity, indeed appears capable of obtaining a prototype of a device capable of sensing the occurrence of particular genes or sequences in the sample under investigation. The validity of the nanogravimetric assay was confirmed by independent fluorescence measurements utilizing DAPI and a CCD camera.

Biosensing Techniques↗
PubMed1997

Clinical isolates of Staphylococcus aureus have osteolytic surface proteins and a proportion of the population have antibodies that block this activity: is this of prognostic significance?

Staphylococcus aureus is directly implicated in the bone destruction associated with infected orthopaedic implants and bacterial arthritis. The Oxford (laboratory) strain of this organism has surface-associated proteins (SAPs) which have potent osteolytic activity. In this study, we have examined the osteolytic activity of SAPs from clinical isolates and also investigated the role of the humoral immune response to such proteins. Nine patients with infected orthopaedic prostheses or infective arthritis, and six volunteers not suffering from overt S. aureus infection, were examined. The sera from 5/9 patients and 4/6 volunteers were able to neutralize the osteolytic activity of the SAPs. The SAPs were extracted from four clinical isolates and were found to have osteolytic activity, but with a wide range of efficacies and potencies. All four patients from whom the clinical isolates were obtained had serum IgG antibodies to the surface proteins from their autologous isolates as determined by ELISA. In conclusion, clinical isolates of S. aureus contain osteolytic SAPs which may be responsible for bone destruction. Apparently disease-free individuals and patients have antibodies able to block this activity. However, since the capacity of patients' sera to neutralize the activity of the SAPs derived from their own S. aureus isolate was not investigated, it is unclear whether these findings are of prognostic value.

Antibodies, Bacterial↗
PubMed1996

Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results

INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet.

Journal Article↗
PubMed1996

Bright Spots, Structure, and Magmatism in Southern Tibet from INDEPTH Seismic Reflection Profiling

INDEPTH seismic reflection profiling shows that the decollement beneath which Indian lithosphere underthrusts the Himalaya extends at least 225 kilometers north of the Himalayan deformation front to a depth of approximately 50 kilometers. Prominent reflections appear at depths of 15 to 18 kilometers near where the decollement reflector apparently terminates. These reflections extend north of the Zangbo suture to the Damxung graben of the Tibet Plateau. Some of these reflections have locally anomalous amplitudes (bright spots) and coincident negative polarities implying that they are produced by fluids in the crust. The presence of geothermal activity and high heat flow in the regions of these reflections and the tectonic setting suggest that the bright spots mark granitic magmas derived by partial melting of the tectonically thickened crust.

Journal Article↗
PubMed1996

Improving American Indian Cancer Data in the Washington State Cancer Registry using linkages with the Indian Health Service and Tribal Records.

BACKGROUND: Previous reports have suggested that American Indians are sometimes classified as other races on cancer registries. Also, cancer registries typically do not include data on tribal affiliation. This study determined the extent of racial misclassification of American Indians in the Washington State Cancer Registry (WSCR) and obtained tribal-specific cancer data for Washington State. METHODS: A computer file including persons registered for services with the Portland Area Indian Health Service (IHS) or who were enrolled members of 19 tribes in Washington, Oregon, and Idaho (n = 127,375) was linked with WSCR records of incident cases for 1992 and 1993 (n = 49,420). Linkage was conducted with probabilistic methods using the AutoMatch software package. RESULTS: Of 180 persons recorded as American Indian in the WSCR, 130 (72.2%) were identified in the IHS/tribal roll file. Of 259 American Indians included in the IHS/tribal file who were identified in the WSCR, 130 (50.2%) were classified as American Indian. The estimated age-adjusted cancer incidence among American Indians in Washington State increased from 153.5 per 100,000 population before record linkage to 267.5 per 100,000 after linkage. Of the 259 persons who were linked to the WSCR, 17 were not registered with IHS and appeared solely in the tribal rolls. Only two tribes had more than five identified cancer cases during the 2-year study period. CONCLUSIONS: The number of IHS-enrolled American Indians or tribal members included in the WSCR would be underestimated by one third in the absence of record linkages, and the estimated cancer incidence of 43.6% would be lower before linkage. It is feasible to obtain tribal-specific cancer rates by linking tribal rolls to cancer registries, although the small number of cases in most tribes is a significant limitation. Further efforts to improve racial classification of American Indians in cancer registries should be undertaken.

Data Collection↗
PubMed1996

Influence of PAX6 gene dosage on development: overexpression causes severe eye abnormalities.

Aniridia in man and Small eye in mice are semidominant developmental disorders caused by mutations within the paired box gene PAX6. Whereas heterozygotes suffer from iris hypoplasia, homozygous mice lack eyes and nasal cavities and exhibit brain abnormalities. To investigate the role of gene dosage in more detail, we have generated yeast artificial chromosome transgenic mice carrying the human PAX6 locus. When crossed onto the Small eye background, the transgene rescues the mutant phenotype. Strikingly, mice carrying multiple copies on a wild-type background show specific developmental abnormalities of the eye, but not of other tissues expressing the gene. Thus, at least five different eye phenotypes are associated with changes in PAX6 expression. We provide evidence that not only reduced, but also increased levels of transcriptional regulators can cause developmental defects.

Animals↗
PubMed1996

NMR characterization of structure, backbone dynamics, and glutathione binding of the human macrophage migration inhibitory factor (MIF).

Human macrophage migration inhibitory factor is a 114 amino acid protein that belongs to the family of immunologic cytokines. Assignments of 1H, 15N, and 13C resonances have enabled the determination of the secondary structure of the protein, which consists of two alpha-helices (residues 18-31 and 89-72) and a central four-stranded beta-sheet. In the beta-sheet, two parallel beta-sheets are connected in an antiparallel sense. From the total of three cysteines present in the primary structure of MIF, none was found to form disulfide bridges. 1H-15N heteronuclear T1, T2, and steady-state NOE measurements indicate that the backbone of MIF exists in a rigid structure of limited conformational flexibility (on the nanosecond to picosecond time scale). Several residues located in the loop regions and at the N termini of two helices exhibit internal motions on the 1-3 ns time scale. The capacity to bind glutathione was investigated by titration of a uniform 15N-labeled sample and led us to conclude that MIF has, at best, very low affinity for glutathione.

Amino Acid Sequence↗
PubMed1996

Sequential assignment of 1H, 13C and 15N resonances of human carbonic anhydrase I by triple-resonance NMR techniques and extensive amino acid-specific 15N-labeling.

The backbone NMR resonances of human carbonic anhydrase I (HCA I) have been assigned. This protein is one of the largest monomeric proteins assigned so far. The assignment was enabled by a combination of 3D triple-resonance experiments and extensive use of amino acid-specific 15N-labeling. The obtained resonance assignment has been used to evaluate the secondary structure elements present in solution. The solution structure appears to be very similar to the crystal structure, although some differences can be observed. Proton-deuteron exchange experiments have shown that the assignments provide probes that can be used in future studies of HCA I.

Amino Acid Sequence↗