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Biomedical subjects

J L Price

Publications and source records attributed to J L Price.

At least 127 records · Page 7Linked to original sources
PubMed1984

The development of lamination of afferent fibers to the olfactory cortex in rats, with additional observations in the adult.

The complementary distribution of the fibers from the olfactory bulb and the intracortical associational fibers to layers Ia and Ib, respectively, of the olfactory cortex has been examined in both adult and neonatal rats, using horseradish peroxidase (HRP) and 3H-leucine as double tracers in the same animal. The observations presented here confirm and extend the previous demonstration (Price, '73) that in the adult the two projections are essentially nonoverlapping throughout the olfactory cortex. Indeed, when the distribution of axons from the olfactory bulb (labeled by HRP inserted into a cut in the LOT) is compared on the same section with that of associational fibers (labeled by 3H-leucine injected into the cortex), the overlap between the two projections is limited to a zone only 5-10 micron in width in both the piriform cortex and olfactory tubercle. In contrast, at P1 the two projections overlap throughout layer I, although the bulbar and associational fibers are slightly concentrated superficially and deeply in layer I, respectively. This overlap is especially prominent in the part of the anterior piriform cortex deep to the LOT. During the remainder of the first postnatal week, this overlap resolves and by P7 the segregation of the two sets of afferent fibers is nearly equivalent to that seen in the adult. However, there are several instances in adults where the segregation of these afferents does not develop. First, a relatively small population of aberrant axons derived from the LOT may be traced from layer Ia into layer Ib and then back to layer Ia. Most of these axons are large in diameter and lack the boutonlike varicosities found on smaller axons in layer Ia. They are most prominent in areas where the cortex is highly curved. Second, in layer I of the nucleus of the lateral olfactory tract, bulbar and associational fibers are extensively intermingled. In this case also, the bulbar fibers are large in diameter with only a few boutonlike varicosities. The developmental emergence of afferent segregation and its breakdown in cases where the fibers from the olfactory bulb do not form boutons suggest that an interaction between the two distinct sets of fibers and the dendritic field is responsible for the normal development of this segregation and that this interaction depends on the process of synaptogenesis.

Afferent Pathways↗
PubMed1984

The development of physiological responses of the piriform cortex in rats to stimulation of the lateral olfactory tract.

Extracellular recording techniques in rats were used to follow the postnatal development of the evoked response of the piriform cortex to electrical stimulation of the lateral olfactory tract (LOT) from birth to adulthood. As in other species, LOT shock in adult rats produces short-latency activation of units in piriform cortex and an extracellular field potential consisting of three components: a surface-negative component, the A1 wave (corresponding to the cortical monosynaptic EPSP evoked by the LOT fibers); a second surface-negative component, the B1 wave (corresponding to reactivation of layer I dendrites by intracortical fibers); and a late surface-positive component, the period 2 wave. A conditioning shock 20-150 msec before the test shock profoundly inhibits both evoked unit activity and the B1 wave, while it facilitates the A1. At birth, units can be orthodromically activated by LOT stimulation in association with the A1 wave. There is also a surface-positive spikelike wave, the S wave, which represents the summation of cortical unit activity. The B1 wave is apparent early in the first postnatal week. However, in contrast to the prominent inhibition in the adults, for the first few days after birth, single-unit responses, multiple-unit activity, and the S wave are all facilitated by a preceding conditioning shock with intervals of 200 msec or less, in association with the facilitation of the A1 wave. A shift to inhibition is apparent with longer intershock intervals of 300-700 msec, which exceed the period during which paired shocks facilitate the A1 wave. During the remainder of the first two postnatal weeks,, partial suppression of evoked activity with intervals of less than 200 msec appears and progressively increases in strength, but inhibition at very long intershock intervals remains greater in magnitude. During this time, the duration of the inhibitory period also decreases to near the adult value of 200-300 msec. In the third postnatal week the pattern was similar to that in the adult, but the inhibition was still clearly weaker than in adults. These results suggest a delayed maturation of the cortical inhibitory circuitry; this conclusion has also been suggested by previously published observations in the developing neocortex and hippocampus. In addition, the acceleration with age of the conduction velocity of axons in the LOT was analyzed. The adult value of 9.6 m/sec was not achieved until some time after postnatal day 15, which parallels the myelinization of the tract as observed with the light microscope.

Aging↗
PubMed1984

Fiber systems in the olfactory bulb and cortex: a study in adult and developing rats, using the timm method with the light and electron microscope.

The structure of the olfactory bulb and cortex of rats is described using the Timm method, in which endogenous transition or "heavy" metals are precipitated with sulfide and then stained with silver. With the light microscope, two types of staining, a fine, "colored" reaction and a coarse, "granular" reaction, are found in the neuropil of the adult forebrain; neuronal somata, fiber tracts, and some specific areas of the neuropil are almost unstained. With the electron microscope the Timm method consists of small silver granules, which are associated with axon terminals. These granules are located over the external surface of the presynaptic membrane, facing the synaptic cleft, and over synaptic vesicles, especially the internal surface of the vesicle membrane. This localization suggests that the reactive metals are related to a membrane component which is recycled during secretion of synaptic transmitters. The colored and granular reactions seen with the light microscope appear to be correlated with different intensities of staining of different types of axon terminals. The full extent of the olfactory cortex can be delineated by a bilaminar staining pattern in layer I, which coincides with the pattern of termination of fiber systems to the cortex demonstrated by axonal tracing experiments. The superficial part of layer I is very palely stained; this corresponds precisely to layer Ia, the zone of termination of fibers from the olfactory bulb. In contrast, the deep part of the layer is stained with an intense colored reaction; this corresponds precisely to layer Ib, the zone of termination of the major association fiber system within the olfactory cortex. A prominent granular reaction, which does not correspond to any known long axon system, is found in all layers of the cortex, although it is concentrated at the superficial edge of layer Ib and in layer II. Variations in staining in the several subdivisions of the olfactory cortex are illustrated and described. In the olfactory bulb, the most prominent staining is a relatively fine, granular reaction in the glomerular formations, which apparently corresponds to the olfactory nerve terminals. In immature rats, the Timm method stains the neuropil throughout the olfactory system, although the patterns and quality of staining differ from that found in adults. Before birth, the best-differentiated reaction is seen in glomeruli of the olfactory bulb and correlates well with the pattern of olfactory nerve ingrowth.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1984

Real-time ultrasonic characteristics of the breast.

An ultrasonic study of the breast of a group of 250 patients attending a breast screening clinic has been performed. Four types of breast can be recognised by their ultrasonic characteristics and the study shows how appearances alter with increasing age. The ultrasonic appearances correlate with the X-ray mammographic patterns described by Wolfe and have increased our understanding of some of the radiographic features. The implications for the use of ultrasound in the diagnosis of lumps and the assessment of mammographic abnormalities, and its potential role as a screening tool, are also briefly discussed.

Aged↗
PubMed1984

Patient education evaluation: beyond intuition.

Intuitive ideas about problem areas gleaned from the literature as well as practice settings can provide nurses with a multitude of patient education evaluation issues. The nurse who is interested in evaluating patient education should review existing studies in the literature, sampling both process and outcome. Thoughtful planning and implementation of a patient education study can be personally satisfying. In addition, such an undertaking will contribute to the body of knowledge in patient education and provide valuable information to other patient educators. It is natural that nurses should pursue the rewards of patient education evaluation for themselves and their patients.

Evaluation Studies as Topic↗
PubMed1984

Repeated screening for breast cancer.

In a screening service for breast cancer the results of routine repeat tests of women will contribute more than the results of their initial tests. A comparison of first and subsequent screens in a group of high risk women suggests that the sensitivity of screening declines between first and subsequent visits, whereas its specificity improves. Despite improved specificity, the ratio of benign biopsies to cancer was worse at repeated screening (21 to 1) than at first screening (6 to 1). This was because between first and subsequent screens the yield of cancers fell to a greater extent than the yield of benign disease. The patients with breast cancer diagnosed during this study were remarkable for their good prognosis, 92% being still alive and 86% free from recurrence at their last follow up, the follow up intervals ranging from four to eight years.

Adult↗
PubMed1983

Individual cells in the nucleus basalis--diagonal band complex have restricted axonal projections to the cerebral cortex in the rat.

Cells in the nucleus basalis--diagonal band complex provide a largely cholinergic projection to all parts of the telencephalon, including the olfactory system, amygdala, hippocampus and neocortex. Experiments using fluorescent dyes as double retrograde axonal tracers indicate that although the projection as a whole is very widespread, the projection of individual cells is limited to a very restricted area within the cortex, not more than 1-1.5 mm in diameter.

Animals↗
PubMed1983

The topographic organization of associational fibers of the olfactory system in the rat, including centrifugal fibers to the olfactory bulb.

This study analyzed the topographic organization of the associational fibers within the olfactory cortex of the rat, by using the autoradiographic method. Small injections of 3H-leucine were placed in all of the subdivisions of the olfactory cortex, to label selectively the fibers arising in each area. Intracortical fibers were identified from all of the olfactory cortical areas except the olfactory tubercle and were classified into two major systems (the layer Ib system and the layer II-deep Ib system) on the basis of their laminar pattern of termination (see Luskin and Price, '83). The layer Ib fiber system arises in the anterior olfactory nucleus, piriform cortex, and lateral entorhinal area, and is broadly organized in relation to the lateral olfactory tract. Cortical areas deep to or near the lateral olfactory tract are preferentially interconnected with areas near the tract, while parts of the cortex lateral and caudal to the lateral olfactory tract are most heavily interconnected with areas lateral, caudal, and medial to the tract. Commissural projections from the anterior olfactory nucleus and the anterior piriform cortex match some (but not all) components of the ipsilateral layer Ib fiber system. The layer II-deep Ib fiber system arises in three small areas--the ventral tenia tecta, the dorsal peduncular cortex, and the periamygdaloid cortex. The fibers from the ventral tenia tecta terminate in layer II of the anterior olfactory nucleus and are topographically organized. The fibers from the dorsal peduncular cortex and the periamygdaloid cortex are more widely distributed, especially in the lateral and caudal parts of the cortex. Two other intracortical projections do not fit into either of these fiber systems. The nucleus of the lateral olfactory tract projects bilaterally to the islands of Calleja and the medial edge of the anterior piriform cortex. The anterior cortical nucleus projects to many parts of the olfactory cortex, but the fibers end in both superficial and deep parts of layer I (layer Ia and Ib). There are projections from several of the olfactory cortical areas to the cortical areas surrounding the olfactory cortex. Virtually all of the olfactory areas also project to the ventral and dorsal endopiriform nuclei deep to the piriform cortex and/or to the polymorph zone deep to the olfactory tubercle. In addition, projections have been demonstrated to the deep amygdaloid nuclei, especially from the more ventromedial and caudal parts of the olfactory cortex.

Amygdala↗
PubMed1983

The laminar distribution of intracortical fibers originating in the olfactory cortex of the rat.

In this study, the autoradiographic method for tracing axonal connections was used to identify the laminar distribution of intracortical fibers originating in the olfactory cortical areas of the rat. Most of the projections can be divided into two major fiber systems with different laminar patterns of termination. The first of these, termed the layer Ib fiber system, arises in the anterior olfactory nucleus, the anterior and posterior piriform cortex, and the lateral entorhinal cortex, and terminates predominantly in layer Ib and, in many cases, layer III of the entire olfactory cortex. The second system, termed the layer II-deep Ib fiber system, originates in three relatively small olfactory cortical areas--the dorsal peduncular cortex, the ventral tenia tecta, and the periamygdaloid cortex--and terminates in and around the cells of layer II in most parts of the olfactory cortex. There is significant overlap in the laminar distribution of the two systems, although the distinction between them is readily apparent. Within the layer Ib fiber system there are relatively slight but consistent differences in the lamination of fibers from different areas. The fibers from the anterior olfactory nucleus are concentrated in the deep part of layer Ib while those from the anterior piriform cortex are concentrated in the superficial part of this layer. The fibers from the posterior piriform cortex tend to be densest in the middle of layer Ib. These differences are maintained in all areas of termination of each set of fibers, both ipsilaterally and contralaterally. In addition, intracortical fibers from the anterior cortical nucleus of the amygdala are distributed throughout layer I, including layer Ia and Ib. Fibers from the nucleus of the lateral olfactory tract terminate bilaterally around the cells of the islands of Calleja and the medial edge of the anterior piriform cortex.

Amygdala↗
PubMed1983

Evidence for an amygdaloid projection to premotor cortex but not to motor cortex in the monkey.

Previous studies in the cat have demonstrated a direct projection from the amygdaloid complex to motor and premotor regions of the neocortex. In the present study both anterograde and retrograde tracer techniques have been used to determine whether a similar projection exists in the monkey brain. We have found that the dorsal, magnocellular division of the basal nucleus of the amygdaloid complex gives rise to a projection to the premotor cortex (Area 6), which terminates principally in layers I and II, and to a lesser extent in layer VI. No component of the amygdaloid complex has been found to project to the motor cortex (Area 4). The amygdaloid projection to Area 6 in the monkey appears to be substantially weaker than other rostrally directed projections from the basal amygdaloid nucleus to orbitofrontal and medial frontal areas, and also relatively weaker than the projection that has been described in the cat.

Afferent Pathways↗
PubMed1983

Dual olfactory representation in the rat thalamus: an anatomical and electrophysiological study.

A combination of electrophysiological and anatomical techniques was used to determine the sites of termination of olfactory projections to the thalamus and the distribution of the cells of origin of these projections within the olfactory cortex. Following electrical stimulation of the olfactory bulb, short-latency unit responses were recorded not only in the central segment of the mediodorsal thalamic nucleus but also in the ventral and anterior parts of the submedial thalamic nucleus. Responses were not obtained in the ventral or lateral parts of the mediodorsal nucleus, in the dorsal part of the submedial nucleus, or in the intralaminar nuclei between the mediodorsal and submedial nuclei. The cells of origin of the projection were identified by making injections of horseradish peroxidase conjugated to wheat germ agglutinin (HRP WGA) into the thalamus and examining the olfactory cortex for retrogradely labeled cells. Following injections into the mediodorsal nucleus, labeled cells were found in the polymorphic cell zone deep to the olfactory tubercle, in the ventral endopiriform nucleus deep to the piriform cortex, and in an equivalent position deep to the periamygdaloid and lateral entorhinal cortices. After injections into the submedial nucleus, a smaller number of labeled cells were found in similar locations, except that they were restricted to the rostral olfactory cortical areas and were not found deep to the lateral part of the piriform cortex. Retrogradely labeled cells and anterogradely labeled axons were also found in the lateral orbital and ventral agranular insular areas of the prefrontal cortex with injections into the mediodorsal nucleus, and in the ventrolateral orbital area with injections into the submedial nucleus. Anterograde tracing experiments, using the autoradiographic method, have confirmed these results. Injections of 3H-leucine deep to the junction between the anterior piriform cortex and the olfactory tubercle label axons in both the central segment of the mediodorsal nucleus and the ventral part of the submedial nucleus, while injections deep to the posterior piriform cortex label axons in the mediodorsal nucleus only. Within the mediodorsal nucleus, the projection also appears to be organized so that fibers which arise more rostrally terminate ventrolaterally in the central segment, while fibers which arise more caudally terminate more dorsomedially. These results indicate that there is a substantial and possibly dual thalamocortical mechanism available for processing of olfactory stimuli.

Animals↗
PubMed1983

An air pressure system for the injection of tracer substances into the brain.

A system for injecting traces and other substances into the brain through glass micropipettes using mechanically or electromechanically regulated air pressure as the driving force is described. The system has a number of advantages over currently used devices including: accurate ejection of a wide range of volumes (2 nl to several microliters); the capability to inject all currently utilized tracers; and, the direct visualization of the volume of solution injected. This system has proven reliable for a number of tract tracing experiments ranging from the injection of tracers into deep structures of the monkey brain to injecting small quantities of tracers into the brains of fetal rats.

Air Pressure↗
PubMed1983

The mammographic features of infiltrating epitheliosis.

The clinical, radiological and histological findings are described in nine cases of infiltrating epitheliosis. In seven cases the mammogram revealed 2.5-5.0 cm discoid radial scars which conformed with the histological features and there was no associated significant clinical abnormality. It can be difficult to differentiate the mammographic appearance of infiltrating epitheliosis from those of carcinoma with confidence but, taken in conjunction with the absence of clinical findings, the changes in the larger lesions are sufficiently distinctive to arouse considerable suspicion. The prevalence of the condition is estimated at 0.4/1000 women in the 45-65 years age range.

Breast↗
PubMed1983

Tungsten anode tubes with K-edge filters for mammography.

A number of authors have calculated the optimum X-ray energies for mammography using, as a criterion, the maximum signal to noise ratio (SNR) per unit dose to the breast, or conversely the minimum exposure for constant SNR. Filters having absorption edges at appropriate energy positions have been used to modify the shape of tungsten anode spectra to bring them close to the calculated optimum. The suitability of such spectra for practical use has been assessed by comparing both the film image quality and the incident breast dose obtained using a K-edge filtered tungsten anode tube with that obtained using a molybdenum anode tube. Image quality has been assessed both by using a "random" phantom and by comparing mammograms of women attending a screening clinic where one breast was radiographed using a filtered tungsten anode tube and the other using a standard molybdenum anode unit. Relative breast doses were estimated from both ionisation chamber measurements with a phantom and thermoluminescent dosimetry measurements on the breast. The film image quality assessment indicated that the filtered tungsten anode tube gave results which were not significantly different from those obtained with a molybdenum anode tube for a tissue thickness of about 4 cm and which were better for larger breast thicknesses. The dose could be reduced to between one-half and one-third with the filtered tungsten anode tube.

Female↗
PubMed1983

Invasive breast cancer--the tip of an iceberg.

Use of large (6 in. X 4 in.) paraffin sections in the routine examination of specimens from patients with operable breast cancer has revealed multiple quadrant involvement by carcinoma in 20% of 186 consecutive cases. Eighty-nine per cent of patients had invasive carcinomas, which were associated with carcinoma in situ (CIS) in 71%. CIS was frequently extensive, and in 47% was remote from the principal invasive lesion. Fourteen patients had multifocal invasive disease with 34 separate primary tumours. The involvement of 32% of sampled axillary nodes by tumour, combined with this significant incidence of multiple quadrant disease, brings into question the rationale of local surgery in most cases even of early breast cancer. Mastectomy with node sampling permits full assessment of the extent of disease, which is essential for the logical selection of patients for adjuvant therapy. The potential role for limited surgery in non-invasive and very small invasive tumours in combination with radiotherapy remains under evaluation.

Adult↗
PubMed1983

The Guildford breast screening project.

Of the 24 069 women aged 45-64 registered with a Practitioner in the South West Surrey Health District 69% attended for breast cancer screening by clinical examination and mammography, with the resultant cancer detection rate of 5.5/1000 women screened and a cancer: benign biopsy rate of 1:1.77. These cancers represent 94% of cancers diagnosed in screened women and 84% of all cancers diagnosed in the total population of this age within one year of the screening invitation. Seventy-three percent of the cancers detected by screening and 66% of all cancers diagnosed in the total population within a year of the screening invitation were 2 cm (or less) in maximum diameter.

Biopsy↗