Duplicated pituitary gland and odontoid process. A case report.

The development of the pituitary gland is not well understood, but duplication of the gland, a rare embryonic anomaly, may shed some light on the process. Since 1880 only about 40 cases have been described. A 56-year-old woman complained of chronic bilateral upper extremity paresthesia and numbness along her first three fingers relieved by rest and exacerbated by increased activity. Magnetic resonance imaging of her head and neck showed an incidental discovery of a duplication of the pituitary infundibulum and pituitary fossa. Computed tomography of the neck showed congenital fusion of C2 with C3, C4 with C5, C1 with the occipital bone, and a duplication of the odontoid process. Her physical examination and all laboratory data were negative. Only seven patients with a pituitary duplication have ever survived beyond puberty. While all of these patients had normal mental capabilities, they also all had obvious craniofacial malformations. Unlike our patient, all other reported cases of duplicated pituitaries have been associated with abnormalities of the face or brain. Previously proposed theories for duplicated pituitary glands include failed twinning, teratogens, and an extreme form of the median cleft face syndrome. We feel that the cleft theory developed by Morton et al. best describes the cause of our patient's malformations. Such anomalous presentations will improve our understanding of how the pituitary gland develops and the order in which cranial structures develop to cause these cranial malformations.

Functional inferences from reconstructed evolutionary biology involving rectified databases--an evolutionarily grounded approach to functional genomics.

If bioinformatics tools are constructed to reproduce the natural, evolutionary history of the biosphere, they offer powerful approaches to some of the most difficult tasks in genomics, including the organization and retrieval of sequence data, the updating of massive genomic databases, the detection of database error, the assignment of introns, the prediction of protein conformation from protein sequences, the detection of distant homologs, the assignment of function to open reading frames, the identification of biochemical pathways from genomic data, and the construction of a comprehensive model correlating the history of biomolecules with the history of planet Earth.

A state association surveys school nurses to identify current issues and role characteristics.

A state association of school nurses conducted a statewide survey, collaborating with university nursing faculty to secure necessary resources and research expertise. A questionnaire, including demographic, employment, and practice characteristics, was mailed to 340 school nurses in Michigan. The response rate was 49%. Findings demonstrated the complex, multiple roles and responsibilities of school nurses. Two strengths identified were memberships in professional organizations and employer support for continuing education. Issues identified included educational preparation below the recommended baccalaureate level, lack of differentiation in practice based on education, and certification through non-competency-based processes. Isolation and supervision/evaluation by non-nurses were pervasive themes. Findings are relevant for school nurses across the country. Results have been used both locally and at the state level in employer negotiations, with legislators for educational purposes, and in policy development. Strategies for addressing the identified issues are explored, including those facilitated through an association-university collaboration.

A combinatorial distance-constraint approach to predicting protein tertiary models from known secondary structure.

BACKGROUND: Distance geometry methods allow protein structures to be constructed using a large number of distance constraints, which can be elucidated by experimental techniques such as NMR. New methods for gleaning tertiary structural information from multiple sequence alignments make it possible for distance constraints to be predicted from sequence information alone. The basic distance geometry method can thus be applied using these empirically derived distance constraints. Such an approach, which incorporates a novel combinatoric procedure, is reported here. RESULTS: Given the correct sheet topology and disulfide formations, the fully automated procedure is generally able to construct native-like Calpha models for eight small beta-protein structures. When the sheet topology was unknown but disulfide connectivities were included, all sheet topologies were explored by the combinatorial procedure. Using a simple geometric evaluation scheme, models with the correct sheet topology were ranked first in four of the eight example cases, second in three examples and third in one example. If neither the sheet topology nor the disulfide connectivities were given a priori, all combinations of sheet topologies and disulfides were explored by the combinatorial procedure. The evaluation scheme ranked the correct topology within the top five folds for half the example cases. CONCLUSIONS: The combinatorial procedure is a useful technique for identifying a limited number of low-resolution candidate folds for small, disulfide-rich, beta-protein structures. Better results are obtained, however, if correct disulfide connectivities are known in advance. Combinatorial distance constraints can be applied whenever there are a sufficiently small number of finite connectivities.

An analysis of simultaneous variation in protein structures.

The simultaneous substitution of pairs of buried amino acid side chains during divergent evolution has been examined in a set of protein families with known crystal structures. A weak signal is found that shows that amino acid pairs near in space in the folded structure preferentially undergo substitution in a compensatory way. Three different physicochemical types of covariation 'signals' were then examined separately, with consideration given to the evolutionary distance at which different types of compensation occur. Where the compensatory covariation tends towards retaining the combined residue volumes, the signal is significant only at very low evolutionary distances. Where the covariation compensates for changes in the hydrogen bonding, the signal is strongest at intermediate evolutionary distances. Covariations that compensate for charge variations appeared with equal strength at all the evolutionary distances examined. A recipe is suggested for using the weak covariation signal to assemble the predicted secondary structural elements, where the evolutionary distance, covariation type and weighting are considered together with the tertiary structural context (interior or surface) of the residues being examined.

Structured abstracts in MEDLINE, 1989-1991.

OBJECTIVE: To characterize the structured abstracts in biomedical journals indexed in MEDLINE over a three-year period as an initial step in exploring their utility in enhancing bibliographic retrieval. DESIGN: The study examined the occurrence of structured abstracts in MEDLINE from March 1989 to December 1991, characteristics of MEDLINE records for articles with structured abstracts, editorial policies of six selected MEDLINE journals on structured abstracts, and a sample of twenty-five structured abstracts from the six journals. RESULTS: The study revealed that the number of structured abstracts in MEDLINE and the number of MEDLINE journals publishing structured abstracts increased substantially between 1989 and 1991. On average, articles with structured abstracts had more access points (Medical Subject Heading [MeSH] terms and text words) than MEDLINE articles as a whole. The average length of the structured abstract was greater than the average length of all abstracts in MEDLINE. CONCLUSIONS: The presence of structured abstracts may be associated with other article characteristics that lead to the assignment of a higher average number of MeSH headings or may itself contribute to the assignment of more headings. The variations in the structured-abstract formats prescribed by different journals may complicate the exploitation of these abstracts in bibliographic retrieval systems. More research is needed on a number of questions related to the quality and utility of structured abstracts.

A secondary structure prediction of the hemorrhagic metalloprotease family.

A secondary structure has been predicted for the hemorrhagic metalloproteases using a method developed in Zurich that extracts structural information from patterns of conservation and variation in homologous protein sequences. This prediction tests the limits of the method when applied to a small number of homologous sequences that have undergone only modest evolutionary divergence. Predictions were also obtained using a neural network developed by Sander and coworkers, to date the best fully automated method for predicting secondary structure, and using the classical Chou-Fasman and GOR heuristics. The predictions are different. No crystal structure is known within this protein family, but one is expected shortly. Therefore, this prediction should contribute significantly to the evaluation of the relative merits of these prediction methods.

The nitrogenase MoFe protein. A secondary structure prediction.

Surface residues, interior residues, and parsing residues, together with a secondary structure derived from these, are predicted for the MoFe nitrogenase protein in advance of a crystal structure of the protein, scheduled shortly to appear in Nature. By publishing this prediction, we test our method for predicting the conformation of proteins from patterns in the divergent evolution of homologous protein sequences in a way that places the method 'at risk'.

Measuring affective factors in RN/BSN programs.

Assessment of affective outcomes is needed in nursing education. This study examined changes in professional attitudes in RN/BSN programs and the relationships between selected affective factors and professional attitudes. Implications for nursing education are identified relative to student advising/counseling and curriculum.

Home apnea monitoring: mothers' mood states, family functioning, and support systems.

Home apnea monitoring has been used increasingly for infants with or at high risk for apnea. This study examined mood states, perceived family functioning, and perceived support systems of mothers with infants on home apnea monitors from the first week on the monitor through three months after discharge. It also compared these factors in mothers receiving care through an established home monitor program or through their own physicians. Greatest discrepancies in all three areas of study occurred during the first week at home. During this time the group receiving care through private physicians reported higher discrepancy in professional support than that in the home monitoring program. No other significant differences were found between the two groups across time periods. Community health nurses have an important role in assessing and providing counseling concerning the mood disturbance and changes in family functioning that may take place when infants are receiving this therapy, particularly in the initial time at home.

Image processing for the rest of us: the potential utility of inexpensive computerized image analysis in clinical pathology and radiology.

Recent progress in computer technology in both hardware and software, combined with marked cost reductions, have placed quantitatively accurate video densitometry systems within the reach of the individual clinician, biomedical researcher, and community hospital. While much of the attention generated by advances in image processing has focussed on larger scale procedures, such as CAT, chemical shift, and positron emission tomography, important applications can be found for considerably more modest systems. In this article, we discuss three such applications of DUMAS, a personal computer-based imaging system developed by the Image Processing Center at Drexel University. A potential technique for quantifying numbers of estrogen receptors in tumorous breast tissue samples as a predictor of patient responsiveness to hormonal therapy is described first, along with possible sources of error. The second application, also related to clinical pathology and cancer, outlines methods for relating changes in nuclear and cell morphology to the diagnosis of Sezary Cell Syndrome. The utility of binary image filtering methods in the classification of cell types is discussed. The third application involves the development of a semi-automatic procedure for the determination of vessel diameter in arteriograms. A detailed description of the optimization and curve-fitting algorithms is provided along with preliminary test results comparing various approaches. The need for user demand to fuel research and development in small-scale imaging systems is also discussed.

Sources of error in arterial morphometric measurements.

The authors used radiopaque vascular casts to test a new computer-based analysis method that employs a densitometric profile to determine arterial diameters. Results from this method were compared with those obtained with caliper measurements of overhead projection images of the radiograph and direct caliper measurements of the vascular cast. In addition, the corresponding in vivo angiograms were compared with the measurements obtained from the vascular casts. Vessel diameters obtained from cast radiographs by caliper measurement, operator-determined and automated densitometric curve fitting showed excellent correlations with acceptable intraobserver and interobserver variation. All methods, however, underestimated arterial diameters by about 7% compared with diameters obtained from casts by direct caliper measurements. In vivo angiograms revealed smaller arterial diameters than those obtained from specimens. However, we observed higher correlations for measurements at stenotic sites than in non-stenotic regions. Our results suggest definite limitations for the often used direct comparison between in vivo angiographic and postmortem findings.

New techniques for liquid chromatography in open-tubular columns.

Methods for sample introduction, capillary column fabrication, and on-column detection are discussed. A new cross-linked polymer stationary phase coating (based on similar coatings for capillary gas chromatography) is described. Results of separations of urinary components using 16-mum open-tubular columns and electrochemical detection and laser-induced fluorescence detection are shown.