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J L Dahl

Publications and source records attributed to J L Dahl.

At least 37 records · Page 2Linked to original sources
PubMed1993

The Cancer Pain Role Model Program of the Wisconsin Cancer Pain Initiative.

The Cancer Pain Role Model Program was established in 1990 by the Wisconsin Cancer Pain Initiative to train physicians to be role models for appropriate pain management. Community and academic physicians along with their "clinical partners," a nurse or pharmacist, were recruited to attend a 1-day education conference that included lectures, small group workshops, and development of an action plan. A total of 44 physicians and 55 clinical partners have attended two conferences (1990 and 1991). Participants listed 199 activities on their action plans; postconference surveys have documented initiation of 212 projects aimed at educating others, improving clinical care, resource development, educating self, or research. The Cancer Pain Role Model Program appears to be a promising means of transferring cancer pain information, legitimizing cancer pain as an important treatment issue, and institutionalizing cancer pain management.

Education, Medical, Continuing↗
PubMed1992

Reinnervation of villi of rat jejunum following severe mucosal damage.

We studied the time course of the regeneration of the jejunal mucosa of the rat after it was damaged by exposure to the surfactant, benzalkonium chloride. We placed particular emphasis on assessing the morphology of the nerve fibers within the villi during and after regeneration. The application of benzalkonium chloride resulted in virtually complete loss of villi within the treated segment; however, the crypts were only partially damaged. The mucosa began to regenerate within 6 hr of the insult. The villus lengths and crypt depths returned to pretreatment values within two to four days. The mucosal innervation was assessed through immunohistochemistry for vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), and neuron-specific enolase (NSE). At all stages of regeneration, VIP, NPY, and NSE immunopositive fibers within the lamina propria extended to the tips of the villi. The density of the immunopositive fibers in the lamina propria at four days after mucosal insult was similar to that in control tissues regardless of the neuronal marker visualized. We conclude that the nerve fibers innervating the small intestinal mucosa grow at a rate of approximately 100 microns/day and that the entire length of each villus contains nerve fibers throughout the regeneration process. The innervation of the regenerated mucosa appears identical to that of control mucosa.

Animals↗
PubMed1991

Physician cancer pain education: a report from the Wisconsin Cancer Pain Initiative.

The Wisconsin Cancer Pain Initiative was established in 1986 to address the various public and professional barriers to cancer pain management. This report discusses the initiative's model for physician education, which includes increasing factual knowledge, legitimizing cancer pain as an important treatment priority, and developing clinical role models. Our progress in implementing this education model will be discussed.

Education, Medical↗
PubMed1990

The myenteric plexus regulates cell growth in rat jejunum.

The roles of the myenteric and extrinsic nerves in the control of proliferation and cell growth in the rat jejunum were studied. The myenteric plexus and/or the extrinsic nerves in a segment of rat jejunum were ablated by serosal application of the surfactant benzyldimethyltetradecylammonium chloride or by crushing the nerves passing through the mesentery, respectively. Ablation of both myenteric and extrinsic nerves, but not the extrinsic nerves alone, resulted in a significant increase in the mitotic rate of the crypt-epithelial cells and in the size of VIP-immunoreactive neurons in the submucosal plexus. The increased mitotic rate was correlated with an increase in the weight of the mucosa per unit length of gut and in the villus length and crypt depth. Neither extrinsic denervation alone nor serosal application of saline had any effect on these parameters. Our results suggest that the myenteric plexus is able to influence the rate of cell proliferation and cell growth in the rat jejunum.

Animals↗
PubMed1990

Attitudes about cancer pain: a survey of Wisconsin's first-year medical students.

A brief questionnaire was administered to 317 first-year students at Wisconsin's two medical schools to assess their attitudes about cancer pain prior to their entry into medical school. Although the students had a realistic perspective of the prevalence and severity of cancer pain, they displayed a number of negative attitudes that if unchanged would contribute to future inadequate pain treatment. Students (a) greatly exaggerated the incidence of psychological dependence (addiction) in patients treated with opioid analgesics, (b) inappropriately timed maximal analgesic therapy to the duration of life expectancy, (c) felt that a majority of patients with cancer currently receive adequate or excessive analgesic therapy, and (d) believed that increasing pain was invariably related to the development of drug tolerance rather than to progression of the disease. Curricular efforts need to be directed at bringing about changes in students' negative attitudes about cancer pain and its management.

Attitude of Health Personnel↗
PubMed1989

Immunohistochemical localization of choline acetyltransferase in the chicken mesencephalon.

Choline acetyltransferase, a specific marker for cholinergic neurons, has been immunohistochemically localized in the mesencephalon and in the caudal diencephalon of the chicken. A complete series of transverse sections through the mesencephalon is presented. In the diencephalon, cholinergic fibers were found in the stria medullaris, the fasciculus retroflexus, and the ventral portion of the supraoptic decussation. The nucleus triangularis and the nucleus geniculatus lateralis, pars ventralis also contained cholinergic fibers. Small cholinergic cell bodies were found in the medial habenula. In the pretectum, cholinergic fibers innervated the nucleus lentiformis mesencephali and the tectal gray. The nucleus spiriformis lateralis also contained cholinergic fibers, while most of the cell bodies in the nucleus spiriformis medialis were cholinergic. In the mesencephalon, labelled fibers were found in the nucleus intercollicularis and in all layers of the optic tectum except the stratum opticum. The highest density of tectal cholinergic fibers was in the stratum griseum et fibrosum superficiale (SGFS), layer f. Radial cells located in SGFS, layer i were also cholinergic. In the isthmic nuclei, cholinergic fibers were found in the pars magnocellularis, while the pars parvicellularis and the nucleus semilunaris contained labelled cells. The oculomotor, Edinger-Westphal, trochlear, and trigeminal motor nuclei all had cholinergic cell bodies. Cholinergic axons were present in the oculomotor and trochlear nerves. In the tegmentum, cell bodies were labelled in the nucleus mesencephalicus profundus, pars ventralis, while the nucleus interpeduncularis had dense cholinergic innervation. Our localization of cholinergic cell bodies and fibers has been compared with earlier autoradiographic and anatomical studies to help define cholinergic systems in the avian brain. For example, the results indicate that the chicken may have a cholinergic habenulointerpeduncular system similar to that reported in the rat. Establishing the cholinergic systems within the avian midbrain is important for designing future neurophysiological and pharmacological studies of cholinergic transmission in this region.

Animals↗
PubMed1988

Cholinergic neurons containing GABA-like and/or glutamic acid decarboxylase-like immunoreactivities in various brain regions of the rat.

The coexistence of immunoreactivities for choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) and/or gamma-aminobutyric acid (GABA) was revealed in some brain regions of the rat, using the peroxidase-antiperoxidase method. Consecutive 40 micron thick vibratome sections were incubated in different antisera and those cells which were bisected by the plane of sectioning so as to be included at the paired surfaces of two adjacent sections were identified. The coexistence of the immunoreactivities for ChAT and GAD or GABA in the same cell could thus be determined by observing the immunoreactivity of the two halves of the cell incubated in two different antisera. In the retina, cerebral cortex, basal forebrain and spinal cord, colocalization of ChAT-like and GAD-like or GABA-like immunoreactivities was observed in some cell types, whereas no such colocalization was observed in cells in the striatum or brainstem. In the retina, the majority of ChAT-like immunoreactive (ChAT-LI) amacrine cells contained GABA-like or GAD-like immunoreactivity. About half of the ChAT-LI neurons in the cerebral cortex showed GABA-like immunoreactivity. In the basal forebrain only a small proportion of ChAT-LI neurons (0.6%) contained GAD-like immunoreactivity. In the spinal cord, about one-third of ChAT-LI central canal cluster cells and about half of ChAT-LI dorsal horn cells showed GAD-like and/or GABA-like immunoreactivities. These observations indicate the possible coexistence of two classical transmitters, GABA and acetylcholine, in various brain regions and spinal cord of the rat.

Animals↗
PubMed1988

Cholinergic neurons of the chicken ciliary ganglion contain somatostatin.

Somatostatin immunoreactivity was studied in the avian ciliary ganglion by immunocytochemistry and radioimmunoassay. Immunoreactivity was localized to small diameter cell bodies of neurons from embryos, newly-hatched and adult preparations. Immunostaining of ganglia with a mixture of antisera to substance P and monoclonal antibody to somatostatin indicated that a number of somatostatin-immunoreactive neurons were surrounded by substance P-immunoreactive boutons, which characteristically terminate on choroidal neurons. Staining with a mixture of antisera to choline acetyltransferase and antibody to somatostatin showed that the somatostatin-immunoreactive neurons were less intensely-stained for choline acetyltransferase than were the neurons lacking somatostatin immunoreactivity. Bundles of nerve fibers showing somatostatin and choline acetyltransferase immunoreactivity were found in the choroid layers of the eye. Radioimmunoassay indicated the presence of somatostatin immunoreactivity in both chick and quail ganglia; the somatostatin immunoreactivity eluted from high pressure liquid chromatography in the same positions as authentic somatostatin 14 and 28. These results show that somatostatin is contained in cholinergic choroidal neurons in the chick and quail ciliary ganglion.

Animals↗
PubMed1987

Localization of choline acetyltransferase-like immunoreactivity in the embryonic chick retina.

Putative sites of acetylcholine synthesis in the retina of the embryonic and posthatched chick were localized immunohistochemically with antisera to choline acetyltransferase; the resultant choline acetyltransferase-like immunoreactivity (ChAT-IR) was compared to demonstrated sites of acetyltransferase (AChE) activity, and changes were followed in localization during development. The results confirmed the early and rapid course of development of the chick's retinal cholinergic system described in previous biochemical and morphological studies. Immunoreactivity was first detected at embryonic day 6.5 in cells close to the retina's vitreal surface. By 8 days it was present in cells in two juxtaposed rows; by the ninth day the two rows were separated and immunoreactivity was evident in two subliminae of the inner plexiform layer. On the tenth day distribution was like that in the posthatched chicken, in type I cholinergic cells in the inner nuclear layer and in type II cells in the ganglion cell layer (Millar et al.: Neurosci. Lett. 61:311-316, '85), and similar to that of most vertebrates. Three days before hatching, a third population of weakly immunoreactive cells (type III cells) appeared within the inner nuclear layer. The onset of localizable ChAT-IR occurred in amacrine cells and in their processes, before the period of synaptogenesis. Acetylcholinesterase activity was localized at an earlier age than ChAT-IR, and at all ages was present in more cells. The results obtained support the view that "displaced" cholinergic amacrine cells begin to differentiate at the same time and in the same retinal region as type I cholinergic cells. Separation of the two groups is a consequence of the ramification of processes of amacrine and ganglion cells rather than a result of the secondary migration of cells between layers.

Acetylcholinesterase↗
PubMed1987

Effect of chemical ablation of myenteric neurons on neurotransmitter levels in the rat jejunum.

We have quantified neurotransmitter changes in the rat jejunum in which the myenteric neurons were ablated by serosal application of benzalkonium chloride. Within 2 days after benzalkonium chloride treatment, there was a 40% reduction in the activity of choline acetyltransferase, a specific marker for cholinergic neurons, and a 25% reduction in the amount of vasoactive intestinal peptide per centimeter length of jejunum. By 15 days, levels were comparable to those in control segments, and by 45 days after myenteric neuronal ablation, levels in treated tissues were twice those in controls. In contrast, we observed no reduction in the amount of leucine-enkephalin per centimeter length of jejunum at early times after benzalkonium chloride treatment, although by 45 days, levels of this neurotransmitter in treated segments of jejunum were more than twice those in controls. Significant increases in muscle thickness and tissue weight were also observed at 15, 30, and 45 days after myenteric neuronal ablation. Thus we have observed that in response to chemical ablation of myenteric neurons in the rat jejunum, there is a thickening of the smooth muscle layers and a compensatory increase in the production of certain neurotransmitters by the surviving neuronal elements in the gut.

Animals↗
PubMed1986

Endogenous analgesia in the pregnant rat: an artifact of weight-dependent measures?

It has been reported that pregnancy produces an opioid-mediated, endogenous analgesia in the rat. In an attempt to confirm this finding, we used 5 different analgesic measures to compare the responsiveness of pregnant and non-pregnant female rats to painful stimuli. Pregnant and non-pregnant rats differed only when assessed by measures that were highly correlated with body weight. Furthermore, the reduced pain responsiveness of pregnant rats was not prevented by administration of the opioid antagonists, naloxone or naltrexone. We can find no evidence for an endogenous analgesia of pregnancy; instead, our results suggest that findings of a diminished response to painful stimuli in pregnant rats may be an artifact related to the greater body mass/weight of the pregnant animals.

Animals↗
PubMed1984

CSF beta-endorphin and the severity of pain.

Beta-endorphin-like immunoreactivity (i beta-EP) was measured in the CSF at myelography of 24 patients suspected of vertebral disk disease. Patients made several ratings of mood and pain for the 24 hours preceding myelography. Composite scores for pain, negative mood, and positive mood were derived by factor analysis. Pain Factor scores were negatively correlated with i beta-EP (r = -0.59, p less than 0.001), indicating a possible role for i beta-EP in the perception of the severity of pain. No significant correlation was shown between Positive or Negative Mood Factor scores and CSF i beta-EP. A physiologic indicator of pain severity is discussed.

Emotions↗
PubMed1983

Conditioned morphine tolerance in the rat: absence of a compensatory response and cross-tolerance with stress.

In four separate experiments with rats as subjects, strong evidence was obtained that tolerance development to morphine analgesia occurs most rapidly when morphine delivery is paired with salient contextual cues. However, contextual cues previously paired with morphine did not elicit conditioned drug-compensatory responses when presented to nondrugged animals. These results were obtained by different analgesia assessments, with different drug-administration--analgesia-test latencies, and in environments differing with respect to stress level. Stress level did influence nociceptive response, as it was found that the combination of bright illumination, white noise, and a strong odor resulted in antinociception in the absence of drug. Moreover, rats that had a history of receiving morphine in this stressful context were tolerant to this stress-induced antinociception, but only when morphine was present in their systems. In the final two studies, this antinociception, which was cross-tolerant with morphine, was characterized with respect to naloxone reversibility and brain levels of met- and leu-enkephalin as determined by radioimmunoassay.

Animals↗
PubMed1983

The development of peptidergic neurons in the foregut of the chick.

We have used antisera specifically directed against Met-enkephalin (met-ENK), somatostatin (SOM), substance P (SP), and vasoactive intestinal peptide (VIP), to study the development of neurons containing these peptides in the foregut of the chick. All four peptides were detected early in ontogeny, at 4 to 9 days of incubation (d.i.), and were localized primarily to cell bodies in the primitive myenteric plexus. There were differences in the times at which they were first detected and in the sequence of their appearance in the proventriculus, gizzard, and duodenum. The differentiation of these peptidergic neurons in the duodenum was examined in some detail. Cell bodies containing these peptides were first detected in the primitive myenteric plexus at 5 to 7 d.i. and increased in number from 7 to 11 d.i. Processes containing varicosities became prominent between 11 and 13 d.i. VIP was the first of the peptides to appear in the submucosal plexus and was found in more proximal regions of the duodenum at 5 d.i. Shortly thereafter, SOM- and SP-containing cell bodies were seen; met-ENK-containing cell bodies were never detected in the submucosal plexus. At 13 d.i., the circular smooth muscle contained a number of VIP-immunoreactive and a smaller number of SOM-immunoreactive processes. met-ENK- and SP-immunoreactive processes appeared in the circular smooth muscle between 17 and 21 d.i.; VIP- and SP-immunoreactive processes appeared in the mucosal plexus at 17 to 21 d.i. Our results suggest that neuropeptides appear very early in the ontogeny of enteric neurons, at the same time or even before cholinergic and serotonergic neurons express their phenotypes. These findings argue against a sequential developmental order in which peptidergic neurons appear after those containing acetylcholine and serotonin.

Animals↗