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Biomedical subjects

R L Anderson

Publications and source records attributed to R L Anderson.

At least 73 records · Page 4Linked to original sources
PubMed1997

"Pneumofornix" (air under the eyelid): a normal finding.

Normal pockets of air under the eyelids have not been previously described in the literature. To assess the incidence and patterns of normal air bubbles in the region of the eyelid, computed tomography (CT) scans of 126 normal orbits and 36 orbits of patients with thyroid orbitopathy were assessed. Twenty-eight (22%) of the normal orbits and 14 (39%) of the thyroid orbits had a well-defined medial or lateral air bubble (or both) on axial views (.1 > P > .05). Oval central or paracentral air bubbles in sections through the superior or inferior fornix were seen in 19 (15%) of the normal orbits and 10 (28%) of the thyroid orbits (.1 > P > .05). It is important to be aware of the incidence and patterns of these normal air bubbles to ensure their accurate differentiation from pathologic air bubbles.

Adolescent↗
PubMed1997

An orbital abscess secondary to acute dacryocystitis.

An orbital abscess is an ophthalmic surgical emergency that is typically caused by the spread of bacteria from adjacent structures, such as the sinuses, eyelids, or teeth. Although acute dacryocystitis is commonly associated with preseptal cellulitis, it rarely causes orbital infection. Infection of the lacrimal sac will typically localize in the preseptal space because the lacrimal sac lies anterior to the orbital septum. To the authors' knowledge, this is the first report of an intraconal abscess secondary to acute dacryocystitis. The key points in the surgical management of this entity are discussed.

Abscess↗
PubMed1996

Non-noradrenergic sympathetic neurons project to extramuscular feed arteries and proximal intramuscular arteries of skeletal muscles in guinea-pig hindlimbs.

This study set out to examine the non-noradrenergic sympathetic innervation of extramuscular and intramuscular arterial vessels supplying hindlimb muscles of guinea-pigs, using multiple-labelling fluorescence immunohistochemistry. Non-noradrenergic axons, identified by their immunoreactivity (IR) to vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), innervated nearly all (> or = 88%) extramuscular feed arteries supplying muscles of the medial thigh. The distribution of non-noradrenergic axons along extramuscular feed arteries was often patchy, with increased density near some branch points. The density of axons with VIP-IR and NPY-IR at the adventitia-medial junction of the largest extramuscular arteries was similar to the density of noradrenergic axons identified by IR to tyrosine hydroxylase (TH) and NPY. The proportion of arterial vessels innervated by VIP-IR axons decreased in more distal, intramuscular arterial segments, and when present, the VIP-IR axons were fewer in number than TH-IR axons innervating the same segments. Distal arterioles (< 20 microns diameter) were never innervated by VIP-IR axons, but always by TH-Ir axons. The non-noradrenergic sympathetic neurons are almost certainly vasodilator neurons. The prominent innervation of extramuscular feed arteries by sympathetic non-noradrenergic neurons has not been reported previously, even in cats and dogs where there is good physiological evidence for a sympathetic vasodilator response in skeletal muscles. The present morphological results provide compelling reasons for re-evaluating the functional role of sympathetic vasodilation in skeletal muscles of rodents, particularly in relation to the role of feed arteries in neural regulation of muscle blood flow.

Animals↗
PubMed1996

The subaffective-character spectrum subtyping distinction in primary early-onset dysthymia: a clinical and family study.

In 1983, Akiskal proposed that primary early-onset dysthymia should be divided into two subtypes: subaffective dysthymia, which is a subsyndromal form of major mood disorder; and character spectrum disorder, which is a form of personality disorder with secondary dysphoria. The present study attempted to validate this distinction. Akiskal's (1983) criteria were applied to a sample of 97 early-onset dysthymic outpatients, yielding groups of 41 subaffective and 56 character spectrum patients. Patients were evaluated using structured interviews for Axis I and II disorders, family history of psychopathology, and the early home environment, and a comprehensive battery of questionnaires. In addition, direct and family history interviews were conducted with their first-degree relatives. There was mixed support for Akiskal's typology. Consistent with the model, subaffectives exhibited higher rates of major depression, depressive symptoms, and a number of depressive personality and cognitive features. In addition, there was a higher rate of alcoholism among the relatives of character spectrum patients. However, contrary to Akiskal's model, the groups did not differ on gender, unstable personality disorders, family history of mood disorders, or the early home environment.

Adult↗
PubMed1996

Analysis of heat shock protein 70 in human chromosome 21 containing hybrids.

An Hsp70 gene, HspA3, has been given provisional assignment to chromosome 21 based on the heat induced expression of a 70 kDa protein in a Chinese hamster ovary-human hybrid cell line. This assignment has not been supported by hybridization data or by cloning of the gene. The aim of the current study is to clarify this localization. We have analysed a series of Chinese hamster ovary-human hybrid lines containing human chromosome 21 by two-dimensional gel electrophoresis and Western blot analysis with anti-Hsp70 antibodies. Only one of these, hybrid 72532-X6, was found to contain an additional Hsp70 protein. Three other hybrid cell lines spanning different parts of chromosome 21 did not contain any additional Hsp70 proteins. The Hsp70 protein in 72532-X6 is constitutively expressed and is not heat inducible. Southern blot analysis indicates that this protein is not the major human cognate protein, Hsp73 (Hsp70-8), but may be one of the other cognate Hsp70s. Our data indicate that hybrid cell lines containing human chromosome 21 do not express a human Hsp70, as has been reported previously. The recent report that the hybrid cell line used to make this claim also contains other human chromosome fragments leads us to conclude that an Hsp70 gene is not localized on human chromosome.

Animals↗
PubMed1996

Parental hypertension and cardiac alterations in normotensive children and adolescents.

The objective of this investigation was the examination of the relation of left ventricular mass (LVM) and function with cardiovascular response to exercise in normotensive adolescents at risk for hypertension. Carried out was a prospective, cross-sectional study of 47 subjects (age, 10 to 18 years), who underwent dynamic and isometric exercise, 24-hour Holter monitoring, and echocardiography. Twenty-nine had normotensive parents (group 2, "at risk"). Both groups were similar for age, race, sex, body mass index, blood pressures, and resting heart rates. Group 2 had a higher E/A ratio (2.3 +/- 0.5 vs 2.0 +/- 0.5; p = 0.039) and higher heart rates during stage IV of dynamic exercise (188 +/- 20 beats/min vs 176 +/- 18 beats/min; p = 0.046). The LVM, 24-hour heart rates, and exercise systolic blood pressures (SBP) were similar in both groups. Only in group 2, SBP at peak dynamic and isometric exercise correlated best with LVM (r = 0.74, p < 0.002; r = 0.82, p < 0.001). It is concluded that altered hemodynamic regulatory mechanisms may exist before the establishment of hypertension in normotensive subjects with parental hypertension.

Adolescent↗
PubMed1996

Gram-negative bacteremia in open-heart-surgery patients traced to probable tap-water contamination of pressure-monitoring equipment.

OBJECTIVE: To determine the cause(s) of an outbreak of gram-negative bacteremia (GNB) in open-heart-surgery (OHS) patients at hospital A. DESIGN: Case-control and cohort studies and an environmental survey. RESULTS: Nine patients developed GNB with Enterobacter cloacae (6), Pseudomonas aeruginosa (5), Klebsiella pneumoniae (3), Serratia marcescens (2), or Klebsiella oxytoca (1) following OHS; five of nine patients had polymicrobial bacteremia. When the GNB patients were compared with randomly selected OHS patients, having had the first procedure of the day (8 of 9 versus 12 of 27, P = .02), longer cardiopulmonary bypass (median, 122 versus 83 minutes, P = .01) or cross-clamp times (median, 75 versus 42 minutes, P = .008), intraoperative dopamine infusion (9 of 9 versus 15 of 27, P = .01), or exposure to scrub nurse 6 (6 of 9 versus 4 of 27, P = .001) were identified as risk factors. When stratified by length of the procedure, only being the first procedure of the day and exposure to scrub nurse 6 remained significant. First procedures used pressure-monitoring equipment that was assembled before surgery and left open and uncovered overnight in the operating room, whereas other procedures used pressure-monitoring equipment assembled immediately before the procedure. At night, operating rooms were cleaned by maintenance personnel who used a disinfectant-water solution sprayed through a hose connected to an automatic diluting system. Observation of the use of this hose documented that this solution could have contacted and entered uncovered pressure-monitoring equipment left in the operating room. Water samples from the hose revealed no disinfectant, but grew P aeruginosa. The outbreak was terminated by setting up pressure-monitoring equipment immediately before the procedure and discontinuing use of the hose-disinfectant system. CONCLUSIONS: This outbreak most likely resulted from contamination of uncovered preassembled pressure-monitoring equipment by water from a malfunctioning spray disinfectant device. Pressure-monitoring equipment should be assembled immediately before use and protected from possible environmental contamination.

Adult↗
PubMed1996

Comparison of chemical dehydration and critical point drying for the stabilization and visualization of aging biofilm present on interior surfaces of PVC distribution pipe.

In this study, fixation of attached glycocalyx on the interior surfaces of polyvinyl chloride distribution pipe remnants was compared with and without ruthenium red/osmium tetroxide and, in the final preparatory phase, with chemical dehydration and critical point drying. SEM examination of interior surface of the polyvinyl chloride pipe showed varying concentrations of adherent bacteria, depending on the preparatory technique used. It was concluded that using a combination of ruthenium red/osmium tetroxide and critical point drying is the optimum method for visually demonstrating aging biofilm on the interior surface of contaminated polyvinyl chloride pipe.

Bacterial Adhesion↗
PubMed1996

A hitchhiker's guide to the human Hsp70 family.

The human Hsp70 family encompasses at least 11 genes which encode a group of highly related proteins. These proteins include both cognate and highly inducible members, at least some of which act as molecular chaperones. The location of cognate Hsp70s within all the major subcellular compartments is an indication of the importance of these proteins. The expression of several inducible Hsp70 genes is also an indication of the importance of these proteins in the stress response. The existence of multiple genes and protein isoforms has created confusion in the identification and naming of particular family members. We have compiled, from the literature, a list of genes and genetic loci and produced a two-dimensional protein map of the known human Hsp70 family members. This will enable researchers in the field to quickly and reliably identify human Hsp70s. We have also devised a more rational nomenclature for these genes and gene products which, subject to general acceptance, could be extended to Hsp70 families from other species.

Blotting, Western↗
PubMed1996

Use of hard palate grafts for treatment of postsurgical lower eyelid retraction: a technical overview.

Lower eyelid retraction occasionally occurs following the repair of fractures involving the orbital rims, orbital floor, or complex zygomatic maxillary complex fractures. The surgical repair of these scarred eyelids has been historically difficult. The authors have utilized the principle of releasing the scar tissue and attempting to reposition the eyelid in its normal anatomic position by employing a hard palate mucosal graft spacer to correct the eyelid malposition. In this article, the authors discuss the excellent success they have experienced utilizing hard palate autologous grafts as spacers performing revision of scarred contracted lower eyelid retractors and tightening of the lateral canthal tendon complex. Adherence to the principles delineated in the article can yield excellent functional and cosmetic results.

Adult↗
PubMed1996

Benign orbital fibrous histiocytoma simulating a lacrimal gland tumor.

The case of a patient with a lacrimal fossa mass that was believed to be a primary lacrimal gland tumor is reported. However, at lateral orbitotomy the tumor was found within the lacrimal fossa, but distinct from the lacrimal gland. Histopathology revealed a benign fibrous histiocytoma. The tumor was totally excised, has not recurred over a 3-year follow-up period. This mesenchymal tumor should be included in the differential diagnosis of lacrimal fossa mass in adults.

Adult↗
PubMed1995

Efficiency and accuracy of disease monitoring systems: application of capture-recapture methods to injury monitoring.

Capture-recapture methods were employed to determine the most accurate and efficient approaches to monitor adolescent injuries. Multiple sources were used to ascertain cases of adolescent injuries that occurred between September 1 and December 31, 1991, in a single school district in metropolitan Pittsburgh, Pennsylvania. Eliminating the duplicate cases between the sources revealed 144 verified injuries; 127 (88.2%) were identified by student monthly recalls, 33 (22.9%) by daily attendance records, 58 (40.3%) by medical excuses, and 72 (50.0%) by a 4-month student recall. Capture-recapture analyses were undertaken to assess potential dependencies between the sources, to estimate the degree of underascertainment in the population, and to evaluate the efficiency of the individual sources and the combinations between them. It was estimated that 91% of the cases in the population were ascertained when all four methods of case finding were utilized. Furthermore, the analysis indicated that accurate injury estimates could be achieved using combinations of only two or three of the sources. An analysis of the efficiency of the methods of ascertainment revealed a trade-off between effort (the number of hours needed to identify cases) and the precision (coefficient of variation) of the injury estimates. Capture-recapture analysis not only provided an approach to evaluate and adjust for undercount but also offered a formal means to evaluate the most efficient combination of the sources to maximize completeness while minimizing effort. The use of these techniques has the potential to evaluate and improve injury surveillance as well as other disease monitoring systems.

Adolescent↗
PubMed1995

Exploration of simple insulin sensitivity measures derived from frequently sampled intravenous glucose tolerance (FSIGT) tests. The Insulin Resistance Atherosclerosis Study.

Both abnormal insulin levels and low insulin sensitivity have been implicated as risk factors for Type II diabetes mellitus and cardiovascular disease. While insulin level is relatively simple to assess, direct measurement of insulin sensitivity is much more invasive, costly, and time-consuming. The authors considered eight previously described measures or indices of indices of insulin sensitivity derived from the frequently sampled intravenous glucose tolerance test (FSIGT). Each one was evaluated by strength and consistency of association with insulin sensitivity computed from glucose clamp (SI(clamp)), across three glucose tolerance groups, including participants with normal glucose tolerance (n = 11), impaired glucose tolerance (n = 20), and non-insulin-dependent diabetes mellitus (n = 24). Minimal model analysis (MINMOD SI(22)), based on the 22-sample FSIGT, performed best based on statistical criteria of strong and consistent association with SI(clamp). An insulin sensitivity measure similar to that of Galvin et al. (Diabetic Medicine 1990;9:921-8), defined as glucose disappearance (10-50 minutes) divided by insulin area under the curve above baseline from 0-50 minutes, performed best based on statistical criteria and time-savings. Galvin insulin sensitivity is simple to calculate, requires only a 50-minute FSIGT, and is significantly (p < 0.001) and not inconsistently (p = 0.12 for inconsistent association) associated with SI(clamp) over a wide range of glucose tolerance.

Analysis of Variance↗
PubMed1995

Localization of the gene encoding the human heat shock cognate protein, HSP73, to chromosome 11.

The heat shock cognate protein HSP73 (or HSC70) is a member of the HSP70 multigene family. This protein has several functions, including binding to nascent polypeptides to facilitate correct folding and the uncoating of clathrin-coated vesicles. Analysis of somatic cell hybrids by two-dimensional protein gel electrophoresis revealed the presence of a 73-kDa protein in two hybrids containing human chromosomes 5, 6, 9, and 11 in common. Using Western blot analysis, we demonstrate that this protein is a member of the HSP70 family and, by Southern blot analysis, that the HSP73 gene is located on human chromosome 11. Fluorescence in situ hybridization further localized HSP73 to the region 11q23.3-q25. This region is involved in a number of genetic rearrangements and is associated with several well-characterized tumours.

Animals↗
PubMed1995

Dog model for cerebrovascular studies of the proximal-to-distal distribution of sequentially injected emboli.

This study was undertaken to determine whether microemboli injected in a predetermined sequence would maintain that sequence once they came to rest in brain microvessels. If so, the injection of different-colored microspheres at different times could be used to bracket-in-time emboli that are known to be released into the circulation during cardiopulmonary bypass. We injected different-colored microspheres into the arterial circulation of anesthetized dogs before and after the injection of fat emboli and before and after cardiopulmonary bypass. Coronal slices of the dog brains were embedded in celloidin, sectioned at 100 microns, and stained for alkaline phosphatase. The afferent cerebrovasculature stained dark brown against a light background, and the proximal/distal orientation of many of the arterioles could be determined by following their course within the thick sections. When different types of emboli were found in a single arteriole, they appeared in the order injected or the order of occurrence in the bypass protocol in 99.3% of the 867 such arterioles counted. Therefore, the microemboli maintained their ordered sequence with only a very small degree of mixing. Once they came to rest, there was not sufficient collateral blood flow in the brain microvessels to move them into disordered positions. This dog model should facilitate studies of the time of release of microemboli within narrower windows of time during cardiopulmonary bypass.

Animals↗