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Biomedical subjects

J W Scott

Publications and source records attributed to J W Scott.

At least 55 records · Page 3Linked to original sources
PubMed1990

Anastomotic suture granuloma following radical retropubic prostatectomy.

We report 2 cases of symptomatic suture granuloma formation after erosion of the silk suture (used to ligate the dorsal venous complex) into the urethrovesical anastomosis. Irritative or obstructive voiding complaints, sterile pyuria or hematuria found after radical retropubic prostatectomy mandates urological evaluation, including cystoscopy to rule out anastomotic suture granuloma formation. Although erosion appears to be a rare occurrence, we recommend use of absorbable suture to control the dorsal venous complex and avoid this possible complication.

Aged↗
PubMed1990

Do black family headship structures make a difference in teenage pregnancy? A comparison of one-parent and two-parent families.

"The black communities of the United States have a disproportionate number of single-parent families: In point of fact, over one half of all black families with children are single-parent families; the great majority of these single-parent families are headed by females. The fastest growing segment of single parent families is young never-married females who...have incomes below the poverty line. Using a causal model analysis, this particular study undertook to compare subsamples of continuous two-parent and one-parent families to find out what intra-familial dynamics 'cause' early versus late teenage pregnancy. The results suggest that positive child-parent affect is generally associated with delayed teenage pregnancy, and negative child-parent affect is generally associated with early teenage pregnancy. Moreover, the father's influence is significant in both two-parent and one-parent families."

Black or African American↗
PubMed1990

Control of renal function during intrarenal infusion of endothelin.

It has been demonstrated that bolus injections of a vasoconstrictor derived from endothelial cells, endothelin 1 (ET-1), constricts isolated arteries and increases blood pressure in animals when infused intravenously. The purpose of this study was to examine the direct effects of intrarenal infusions of ET-1 on renal function at doses that do not alter systemic arterial pressure. The effects of ET-1 on renal hemodynamics and electrolyte excretion were examined during 40 min of intrarenal infusions of ET-1 at rates of 1.15 and 5 ng.kg-1.min-1. Infusion of ET-1 (1.15 ng.kg-1.min-1) resulted in a transient increase in renal blood flow (RBF) followed by a progressive vasoconstriction, which reduced RBF by 23%. ET-1 decreased glomerular filtration rate (GFR) and had no significant effect on filtration fraction. Intrarenal infusion of ET-1 (1.15 ng.kg-1.min-1) had no effect on fractional excretion of sodium (FENa) or potassium. Infusion of ET-1 at a higher dose (5 ng.kg-1.min-1) produced further reductions in RBF, GFR, and FENa. These data indicate that ET-1 is a potent renal vasoconstrictor that could play a role in controlling renal hemodynamics.

Animals↗
PubMed1990

Intracellular responses of identified rat olfactory bulb interneurons to electrical and odor stimulation.

1. Intracellular recordings were made from 28 granule cells and 6 periglomerular cells of the rat olfactory bulb during odor stimulation and electrical stimulation of the olfactory nerve layer (ONL) and lateral olfactory tract (LOT). Neurons were identified by injection of horseradish peroxidase (HRP) or biocytin and/or intracellular response characteristics. Odorants were presented in a cyclic sniff paradigm, as reported previously. 2. All interneurons could be activated from a wide number of stimulation sites on the ONL, with distances exceeding their known dendritic spreads and the dispersion of nerve fibers within the ONL, indicating that multisynaptic pathways must also exist at the glomerular region. All types of interneurons also responded to odorant stimulation, showing a variety of responses. 3. Granule cells responded to electrical stimulation of the LOT and ONL as reported previously. However, intracellular potential, excitability, and conductance analysis suggested that the mitral cell-mediated excitatory postsynaptic potential (EPSP) is followed by a long inhibitory postsynaptic potential (IPSP). An early negative potential, before the EPSP, was also observed in every granule cell and correlated with component I of the extracellular LOT-induced field potential. We have interpreted this negativity as a "field effect," that may be diagnostic of granule cells. 4. Most granule cells exhibited excitatory responses to odorant stimulation. Odors could produce spiking responses that were either nonhabituating (response to every sniff) or rapidly habituating (response to first sniff only). Other granule cells, while spiking to electrical stimulation, showed depolarizations that did not evoke spikes to odor stimulation. These depolarizations were transient with each sniff or sustained across a series of sniffs. These physiological differences to odor stimulation correlated with granule cell position beneath the mitral cell layer for 12 cells, suggesting that morphological subtypes of granule cells may show physiological differences. Some features of the granule cell odor responses seem to correlate with some of the features we have observed in mitral/tufted cell intracellular recordings. Only one cell showed inhibition to odors. 5. Periglomerular (PG) cells showed a response to ONL stimulation that was unlike that found in other olfactory bulb neurons. There was a long-duration hyperpolarization after a spike and large depolarization or burst of spikes (20-30 ms in duration). Odor stimulation produced simple bursts of action potentials, Odor stimulation produced simple bursts of action potentials, suggesting that PG cells may simply follow input from the olfactory nerve.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Selection of a management strategy for pediatric brainstem tumors.

Brainstem tumors arise in portions of the rhombencephalon and mesencephalon. Some authorities include diencephalic tumors in this group. We have reviewed our clinical experience of 69 children (less than 21 years of age) with brainstem tumors evaluated and treated at Duke University Medical Center (DUMC) from 1960 to 1986. There were 19 patients with group 1 tumors (thalamus, third ventricle region, or midbrain) and 50 with group II tumors (pons, medulla oblongata). The common presenting signs and symptoms were ataxia, headache, motor loss, and cranial nerve palsies. The most commonly employed diagnostic imaging studies were air examinations and CT. Preradiotherapy confirmation of malignancy was obtained in five group I patients (astrocytoma, 4; germinoma, 1) and 8 group II patients (astrocytoma, 3; anaplastic astrocytoma, 2; glioblastoma multiforme, 3). All patients received radiotherapy. The 5-year survival rate for the entire population was 40%. The survival rate for group I patients was significantly better than that observed for group II patients. In the 50 group II patients neither patient sex nor age nor presence of cranial nerve palsies nor pretreatment CT scan findings nor field size influenced survival. A long duration of symptoms positively influenced survival. The vast majority of tumor recurrences were within the radiation field. Half of the patients had either stable or improved Karnofsky status 6 months following completion of irradiation. The management strategy for childhood brainstem tumors is discussed.

Adolescent↗
PubMed1989

Estimation of ERPF in adults from plasma clearance of 131I-hippuran using a single injection and one or two blood samples.

The plasma clearance of [131I]o-iodohippurate, which is an estimate of effective renal plasma flow, can be measured from one or two blood samples drawn after an i.v. bolus of tracer. The most widely used method is based on a single sample. Here, it is shown that the error (relative to a complete curve of six or more blood samples) can be halved by using two samples rather than one. Since the one-sample method is satisfactory for most clinical purposes, the two-sample method is recommended only when special accuracy is needed.

Blood Specimen Collection↗
PubMed1989

Discrimination among odorants by single neurons of the rat olfactory bulb.

1. Intracellular and extracellular recordings were made from rat olfactory bulb mitral and tufted cells during odor stimulation and during electrical stimulation of the olfactory nerve. Neurons were identified by horseradish peroxidase injections and/or antidromic activation. The presentation of multiple concentrations of at least one odorant in a cyclic artificial sniff paradigm, as reported previously (10), allowed the study of odor responses. This approach was extended to multiple odorants to compare their concentration-response profiles. This procedure avoids the problems of interpretation resulting from nonequivalence of the effective concentrations of different odorants used as stimuli that have characterized previous studies of odor quality effects. Comparisons of intracellular events and responses to electrical stimulation with the odor-induced spike train activity allow us to begin to delineate the local circuitry involved in generating odor-induced responses. 2. The concentration-response profiles of the 72 cells in the present study are comparable to those previously reported for output neurons of the olfactory bulb, showing ordered changes in the temporal patterning of spike activity with step changes in odor concentration. However, eight of the neurons exhibited inhibitory responses to lower concentrations, but excitation, at similar latency, to higher concentrations of the same odorant. These data emphasize that to study pattern changes induced by changing odor quality the influence of stimulus intensity must also be carefully examined. The data also provide evidence that the temporal pattern evoked by an odorant is probably not in itself the code for odor quality recognition. 3. Complete concentration-response profiles, including subthreshold concentrations, to more than one odorant show that, although responses to the different odorant can evolve systematically with concentration, the responses to different odorants can evolve through very different patterns. For example, in some cells, the response patterns to different odors were complementary in form. These results demonstrate that the patterned responses of olfactory bulb neurons can reflect changes in odor quality as well as intensity. 4. Intracellular recording was employed to compare the temporal patterning of spikes during odor stimulation with membrane potential changes. In some cases, the spike pattern was closely correlated with apparent postsynaptic potentials. However, there were several clear exceptions. In five cells, a prominent hyperpolarization, seen in the first sniff of a series of 10 consecutive sniffs, was associated with pauses in spike activity. In the following

Animals↗
PubMed1989

Translating a health professional certification test to another language. A pilot analysis.

There has been increased pressure in recent years for examinations used for occupational and professional credentialing to be offered in several languages. When credentialing programs are international in scope, rather than national, examination translation may be a necessity, and a validation of the translation will be required. Yet, few candidates may sit for the translated version, jeopardizing the power and generalizability of statistical analysis. How should a board proceed in meeting its linguistic responsibility when faced with a small n? This article describes such a situation, and the linguistic and psychometric procedures that were developed and applied on a pilot translation by the International Board of Lactation Consultant Examiners (IBLCE).

Allied Health Personnel↗
PubMed1988

Cytochrome oxidase staining marks dendritic zones of the rat olfactory bulb external plexiform layer.

Cytochrome oxidase staining of the rat olfactory bulb external plexiform layer (EPL) produces a darkly stained intermediate zone bordered by lightly stained superficial and deep zones. Similar zonal staining was seen in cats, rabbits, and hamsters. These zones vary in relative thickness around the circumference of the olfactory bulb; the deep zone is proportionally thicker in the most dorsal and ventral parts of the bulb. Tufted cell somata are unevenly distributed within the EPL; the outer part of the EPL has more somata. The distribution of the cytochrome oxidase reaction product shows that the darkly stained intermediate zone is not produced by staining of tufted cell somata. Zones of cytochrome oxidase staining correspond to the sublaminar distribution of mitral and tufted cell basal dendrites. This was demonstrated by labeling mitral and tufted cells with small extracellular horseradish peroxidase injections and processing alternate sections for horseradish peroxidase and for cytochrome oxidase. Because there was cross-reaction of the cytochrome oxidase procedure with horseradish peroxidase, it was possible to trace many neurons through both series of sections. Middle tufted cells of the superficial EPL have basal dendrites confined to the superficial zone of light cytochrome oxidase staining. Internal tufted cells and middle tufted cells of the intermediate zone send their basal dendrites into the intermediate zone. One group of mitral cells (type I) has basal dendrites confined to the deep zone of lighter cytochrome oxidase staining. A second group of mitral cells (type II) and tufted cells of the intermediate EPL has basal dendrites primarily confined to the intermediate zone of dark cytochrome oxidase staining. The correlation of the enzyme staining with the dendritic laminar patterns supports the existence of three relatively distinct sublaminae in the EPL and supports the designation of two types of mitral cells. The staining pattern also provides an independent method for evaluating the sublaminae of the EPL without the necessity of labeling individual groups of cells. Finally, the staining pattern suggests that the intermediate zone of the EPL may be subjected to more tonic synaptic input, causing it to have an increased level of metabolic activity.

Animals↗
PubMed1988

Effects of renal artery pressure on interstitial pressure and Na excretion during renal vasodilation.

Renal vasodilation has a marked effect on the pressure-natriuresis relationship. The purpose of this study was to determine the role of renal interstitial hydrostatic pressure (RIHP) in mediating the effect of renal perfusion pressure (RPP) on urinary sodium excretion rate (UNaV) in control and vasodilated kidneys. The effects of RPP on UNaV and RIHP were determined in dogs under control conditions and during renal vasodilation with acetylcholine (Ach, 2.0 micrograms.kg-1.min-1) or secretin (SEC, 0.025 micrograms.kg-1.min-1). Decreases in RPP in control kidneys from 130 to 60 mmHg decreased UNaV from 2.9 +/- 0.1 to 0.6 +/- 0.3 microeq/min and fractional excretion of Na (FENa) from 0.15 +/- 0.08 to 0.06 +/- 0.04%. These changes were associated with significant reductions in RIHP (8.9 +/- 0.6 to 5.6 +/- 1.2 mmHg). In Ach-vasodilated kidneys, reductions in RPP from 130 to 60 mmHg decreased UNaV from 149.8 +/- 52.4 to 0.2 +/- 0.1 microeq/min and FENa from 3.42 +/- 1.18 to 0.012 +/- 0.01%. RIHP decreased from 17.8 +/- 3.4 to 8.4 +/- 1.3 mmHg, despite autoregulation of RBF. Renal vasodilation with SEC, which did not affect RIHP, had only a small effect on the relationship between RPP and UNaV. These data suggest that RIHP may be playing an important role in mediating the effect of RPP on UNaV.

Acetylcholine↗
PubMed1987

Short axon cells of the rat olfactory bulb display NADPH-diaphorase activity, neuropeptide Y-like immunoreactivity, and somatostatin-like immunoreactivity.

Several types of short axon cells of the mammalian olfactory bulb have been described after Golgi impregnation. Two of these types have been observed in our material after treatment with the NADPH-diaphorase procedure or after immunohistochemistry for neuropeptide-Y (NPY). The cells stained by the two procedures have similar morphologies and distributions. A less extensive series of observations confirms that similar cells also display somatostatin (SS)-like immunoreactivity. One of these cell types corresponds to the superficial short axon cell of Golgi and electron microscopic studies. The dendrites of this cell lie within the periglomerular region and in the superficial external plexiform layer (EPL), generally lying parallel to the glomerular layer. In some cases the axon has been traced across the EPL into the granule cell layer (GCL). This cell may provide another route of interaction between the periglomerular region and the granule cells in addition to the influences conducted by basal dendrites and axon collaterals of some mitral and tufted cells. A type of deep short axon cell is also visible with these two procedures. It lies deep in the granule cell layer, frequently near the ventricular layer and its dendrites lie parallel to that layer. This deep short axon cell is stained with much greater frequency by the NADPH-diaphorase and NPY procedures than is the superficial short axon cell. It corresponds most closely to the Blanes or Golgi cells of the Golgi impregnation literature, but it appears to differ from these cells in the position and orientation of its dendrites. No spines have been observed on either the superficial or deep cells in this series. Many glomeruli are also stained by the NADPH-diaphorase procedure, but are not NPY or SS immunoreactive. This may provide additional evidence for functional differences between glomeruli in local regions of the olfactory bulb.

Animals↗
PubMed1986

Olfactory bulb responses to odor stimulation: analysis of response pattern and intensity relationships.

Extracellular recordings were made from mitral cells, tufted cells, and presumed glomerular layer and external plexiform layer interneurons of the olfactory bulb of anesthetized rats during odor stimulation. Intensity responses of these cells were studied by presenting a series of six or seven concentrations, spanning a range greater than two log units, in a cyclic artificial sniff paradigm, which produced repeated response measures at each concentration. Experiments focused on obtaining a complete intensity series, including interspersed unstimulated spontaneous activity records, for a single odorant (usually amyl acetate), but concentration responses to other odorants were tested when possible. Odor responses of 46 cells were studied with two approaches. Response form was examined in an attempt to define response classes based on qualitative characteristics of the temporal pattern of response. Assessment of response magnitude was attempted, in order to construct stimulus-response functions for each cell, independent of response form. As previously reported for olfactory bulb cells, the cells in our sample responded to odor stimulation with spike trains of a variety of temporal patterns, consisting of excitatory and inhibitory components that were frequently recognizable in the responses of a cell across a range of concentrations. However, response patterns usually changed significantly with concentration, such that response form across the concentration range could not be predicted from the response at any one concentration. Responses of different cells were sometimes similar to each other in form at one concentration and quite different from each other in the rest of their concentration-response profiles. Classification of response profiles into discrete types, based on consistency of response form throughout the profile, was therefore not feasible. In agreement with other reports, response of a single cell to different odorants sometimes showed similar forms and sometimes showed very different forms across the concentration-response profiles. Since the response form depends on the stimulus intensity as well as the stimulus quality, characterization of response magnitude and of the pattern of response to different odors require testing with a series of stimulus concentrations. Because odor responses consisted of temporally patterned spike trains, whose components changed in complex ways with stimulus intensity, it was not possible to quantify response magnitude by measuring characteristics of particular response components or counting mean frequency.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Quality control of technetium-99m DTPA: correlation of analytic tests with in vivo protein binding in man.

When [99mTc]DTPA is administered, a small fraction of the activity (presumably an impurity) is bound to plasma proteins. This causes an error in the calculation of glomerular filtration rate from plasma clearance. This paper presents two methods of laboratory quality control for measuring the fraction that binds to plasma proteins. One method involves in vitro binding to human serum albumin followed by gel filtration. The other method involves descending paper chromatography on wet pre-equilibrated anion exchange paper. In a series of 80 patients, correlation was demonstrated between laboratory characteristics and actual clinical performance of the [99mTc]DTPA preparation. Both laboratory methods appear suitable for routine quality control.

Blood Proteins↗
PubMed1985

Pattern of rat olfactory bulb mitral and tufted cell connections to the anterior olfactory nucleus pars externa.

The pattern of output of mitral and tufted cells of the rat olfactory bulb (OB) to layer Ia overlying the pars externa (pE) of the anterior olfactory nucleus (AON) has been studied in the rat by iontophoresis of horseradish peroxidase and Phaseolus vulgaris-leucoagglutinin. These agents labeled mitral and tufted cells and at least the proximal portion of their axons. In most cases we observed small branches from axons of the lateral olfactory tract that appear to terminate in the region of the pE AON, while the main axon could often be traced for considerable distances past these branches. These branches are assumed to terminate in the pE AON because they could not be traced to other terminal regions, because they ramify in layer Ia, and because they usually show small swellings characteristic of axons in terminal regions. Although each ramification could be extensive, we found that the positions of these small branches were related to the positions of the injections within the OB. Dorsal medial injections labeled dorsal branches. Ventral medial injections labeled ventral branches. Injections on the lateral face of the OB labeled intermediate branches. The centers of the regions within which branches were labeled were strongly correlated with the positions of the injection around the circumference. Comparison of the anterior-posterior axis of the OB produced no such strong correlation. Reconstructions of axons showed that terminal branches arise from both mitral and tufted cells, although at least some mitral cells are shown not to have such branches in the pE AON. Studies of the patterns of dendrites and terminals in the pE AON indicate that this region has the same pattern of layer Ia and Ib terminals seen in other olfactory cortical regions. The pE AON cell layer is intercalated just below the boundary between layers Ia and Ib. Since dendrites of the underlying pars lateralis of the AON (pL AON) penetrate into layer Ia over much of the pE AON, it is necessary to remember that at least part of the pL AON may also receive topographically organized inputs.

Animals↗