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Biomedical subjects

J Wells

Publications and source records attributed to J Wells.

At least 109 records · Page 6Linked to original sources
PubMed1991

Cross-species septohippocampal transplants: ultrastructure of Thy-1.2-labeled donor fibers into the dentate gyrus.

A naturally occurring species-specific membrane marker was used to identify unambiguously transplanted septal cells and their fibers which have grown into host tissue. Cell suspensions of the septum/basal forebrain region of C57Bl/6 mouse embryos were transplanted into the dentate gyrus of Sprague-Dawley rats that had received a fornix lesion. The membranes of the mouse contained Thy-1.2, while the membranes of the rat contained Thy-1.1. An antibody to Thy-1.2 clearly identified the donor tissue and did not react with the Thy-1.1 of the host's membranes. The ultrastructure of the immunoreactively labeled tissue confirmed previous biochemical findings on the distribution of Thy-1 and showed Thy-1.2 immunoreactivity on axons and dendrites, microtubules, some mitochondrial membranes, and the surface membranes of cell bodies. Within the transplant, a few glial profiles showed immunoreactive fibrils, but most glial profiles within the transplant and all glial profiles outside the transplant were not immunoreactive. Astrocyte fibers enclosed the outgrowing labeled fibers to form fascicles, but did not penetrate the fascicle. There was no other distinctive association of astrocytic profiles with immunoreactive fibers. Dendrites grew for long distances into the host's molecular layer. Many immunoreactive dendritic profiles formed synapses with unlabeled terminal profiles from the host. The host synapses on the long dendrites of the transplanted neurons may form an important source of input for the initiation of physiological activity in the new circuits established by the transplant. A few labeled (donor) synaptic terminals were observed in the molecular layer, but Thy-1.2-labeled dendritic profiles were much more prominent than labeled axonal profiles.

Animals↗
PubMed1991

Pesticide residues in food crops analyzed by the California Department of Food and Agriculture in 1989.

California spends more than $40 million each year for the nation's most comprehensive program to regulate pesticide use: Pesticides are evaluated before they can be used. Businesses that sell or apply pesticides are licensed. Pesticide specialists enforce restrictions on pesticide use. Water, air, and soil are monitored for pesticide levels. And, as a final check in this integrated network of program, domestic and imported produce is sampled and tested for traces of pesticide residue. Annually, approximately 1% of the samples violate established standards. Because the standards include a safety margin, illegal residues rarely present a health risk, according to leading scientific experts, including the World Health Organization.

California↗
PubMed1991

Peripherally evoked single unit responses in ventroposterolateral nucleus in the absence of the dorsal column nuclei in rat.

The present experiments were designed to determine the effects of removing the dorsal column nuclei on the evoked responses of the ventroposterolateral nucleus (VPL) neurons in the rat. Previously, we have observed inhibitory interactions between forelimb and hindlimb inputs to VPL (Roberts and Wells 1990), and have also observed a synaptic recovery process within VPL following dorsal column nuclei (DCN) lesions (Wells and Tripp 1987). In an attempt to describe any changes in VPL responses that correlate with the synaptic recovery in VPL following lesions to the DCN, we have studied the incidence of the inhibition process in VPL, the latency of activation of single unit VPL responses to peripheral nerve stimulation, the number of evoked unit responses observed per track studied and the somatotopy of responses in VPL. Dorsal column nuclei lesions did not alter the incidence or duration of the inhibitory interaction between forelimb and hindlimb inputs to VPL. Following DCN lesions, there was a significant increase in the latency to activation of VPL neurons by both forelimb and hindlimb inputs. This increase in latency returned to a non-significant difference from control over the same interval of time that is required for the structural recovery in VPL. There was a significant reduction in the number of evoked unit responses observed per track studied in the deafferented group at the twenty day post-lesion time course. This difference was no longer statistically significant in the sixty-four day post-lesion group. Finally, we have observed little change in the overall anatomic distribution of responses to forelimb or hindlimb stimulation in VPL following DCN lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Occurrence of schizotypal and borderline symptoms in parasuicide patients: comparison between subjective and objective indices.

Seventy-six patients were interviewed within a week of admission following a parasuicide episode. Axis II diagnosis on DSM-III was made for schizotypal, borderline, histrionic, and antisocial personality disorder. In addition patients completed a self-rating questionnaire, the Schizotypy Questionnaire of Claridge & Broks (1984), which assesses schizotypal and borderline personality traits. The objective and subjective indices of schizotypal and borderline symptoms correlated significantly but allocation of patients to a diagnosis missed several patients who nevertheless rated themselves as having a high frequency of these symptoms. There was an asymmetry of symptom pattern reminiscent of Foulds & Bedford's (1975) hierarchy model. The presence of schizotypal symptoms appeared to be higher in the hierarchy: they predicted borderline symptoms, but a high frequency of borderline symptoms did not necessarily predict schizotypy. We suggest that the occurrence of schizotypal symptoms should become a more explicit focus of clinical assessment and treatment of these patients, especially those who repeatedly harm themselves and we suggest ways in which cognitive therapies may be adapted to do this.

Adolescent↗
PubMed1991

Where physicians practicing in Appalachia in 1978 to 1990 were trained and how they were distributed in urban and rural Appalachia.

Medical school graduates who graduated from 1978 to 1986 were analyzed to determine the health professions' ability worldwide to educate and place primary care physicians in rural areas of Appalachia. These data indicate that the University System of West Virginia--consisting of the West Virginia School of Osteopathic Medicine, West Virginia University Medical School, and Marshall University Medical School--produced the most primary care physicians who began practicing in rural Appalachia during the 1980s. The West Virginia School of Osteopathic Medicine successfully retained 106 (26%) of its graduates in primary care practices throughout rural Appalachia, with 77 of them in rural West Virginia, making the institution the nation's leading provider of primary care physicians practicing in rural Appalachia and West Virginia during this eight-year study period. With the exception of West Virginia, these and additional data support concerns of medical educators and public health officials that physicians in Appalachia are distributed disproportionately, more to urban than to rural counties.

Appalachian Region↗
PubMed1991

Molecular cloning and sequencing of Australian black bream Acanthopagrus butcheri and barramundi Lates calcarifer fish growth hormone cDNA using polymerase chain reaction.

The complementary DNA (cDNA) encoding the preprotein growth hormone (pre-GH) from two Australian marine fish species, namely Acanthopagrus butcheri and Lates calcarifer, have been isolated, cloned and sequenced. The sequences were amplified from reverse transcribed total RNA of whole brains using Polymerase Chain Reaction (PCR) and oligonucleotide primers corresponding to the 5' and 3' regions of Pagrus major. Use of PCR offers a rapid method of isolating fish GH cDNA sequences for commercial and taxonomic applications. Sequence comparison indicates a high degree of conservation for GH cDNAs within the family Sparidae.

Amino Acid Sequence↗
PubMed1991

Introducing patient controlled analgesia--the Gloucester experience.

Patient Controlled analgesia is being given more and more consideration as a method of post-operative pain relief. John Wells describes how it was introduced in Gloucester and considers the need for a multi-disciplinary team to oversee and evaluate its effective use.

Analgesia, Patient-Controlled↗
PubMed1990

Extensive dual innervation and mutual inhibition by forelimb and hindlimb inputs to ventroposterolateral nucleus projection neurons in the rat.

The stimulation of brachial plexus and sciatic nerve resulted in a precisely timed, synchronous volley of inputs to ventroposterolateral (VPL) neurons from either forelimb or hindlimb. Such stimulation activated sensory fibers of all modalities and was therefore modality-nonspecific. Extracellular recordings of modality-nonspecific single-unit evoked responses from VPL showed that 13% of VPL projection neurons responded to both forelimb and hindlimb inputs. We also demonstrated mutually inhibitory interactions between inputs from forelimb and hindlimb in 45% of VPL units. Unlike the somatotopic map produced by others using modality-specific inputs, the modality-nonspecific evoked response map of VPL had a broadly overlapping distribution of evoked responses. This was especially true for the more caudal aspects of VPL. When the delivery of stimuli was appropriately timed, forelimb inputs caused the inhibition of responses to forelimb stimulation; similarly, hindlimb inputs inhibited responses to forelimb stimulation. The inhibition had a variable duration that may reflect a combination of processes, including recurrent inhibitory collateral input from the thalamic reticular nucleus (TRN) or an intrinsic hyperpolarizing inhibitory afterpotential of the VPL neuron. The presence of an extensive converging input on VPL neurons and an inhibitory correlate to this overlapping of inputs may explain the shifting of VPL maps following lesions of peripheral nerve, spinal cord, or dorsal column nuclei (DCN).

Action Potentials↗
PubMed1989

Increase in acetylcholinesterase in the molecular layer of the dentate gyrus in the absence of septal inputs following selective granule cell lesions.

Granule cell lesions cause an increase in acetylcholinesterase (AChE) staining in the molecular layer of the dentate gyrus. The source of this response was examined by combining granule cell lesions with lesions of the fornix-fimbria, thereby removing the cholinergic input from the septum to the hippocampus. The increased AChE staining was present in animals with granule cell lesions regardless of whether the fornix was lesioned or intact. The increase in AChE staining occurred without a corresponding increase in choline acetyltransferase staining. These findings suggest that an AChE-positive, but non-cholinergic, sprouting response occurred within the dentate gyrus following selective lesions of the granule cells. The source of this sprouting may be from AChE-positive hilar interneurons.

Acetylcholinesterase↗
PubMed1989

Hair light guide.

Explore the source record for details and available documents.

Fiber Optic Technology↗
PubMed1989

Interactions between donor and host tissue following cross-species septohippocampal transplants.

Interactions between donor and host tissues following xenogeneic transplantation were studied using the neural cell surface antigen, Thy 1.2, as a marker for the donor tissue. Dissociated septal cells from Thy 1.2-positive fetal mice were transplanted to the dentate gyrus of Thy 1.2-negative adult rats. At post-transplantation survival times between 1 and 5 months, an antibody to Thy 1.2 was used to identify donor tissue. The results demonstrate that the donor tissue was capable of migrating and developing within the host following transplantation. Thy 1.2-positive cells and processes were consistently found within the supragranular, infragranular, and molecular layers of the dentate gyrus, and occasionally within the hilus, suggesting that mechanisms existed within the host which influenced the development of the transplanted tissue. Additionally, the survival and growth of the Thy 1.2-positive neurons differed from previous reports describing the growth of acetylcholinesterase (AChE)-positive fibers from xenogeneic transplants. This finding suggested that in addition to growing within the host, xenogeneic transplants may also stimulate a compensatory sprouting response from the host.

Acetylcholinesterase↗
PubMed1989

Selective lesions of granule cells by fluid injections into the dentate gyrus.

Granule cells were selectively lesioned by injections of fluid into the infragranular cleavage plane in the dentate gyrus. The granule cells were axotomized by the cavity created by the fluid and 6 days after the injection there were no granule cells at the injection site. The size of the granule cell loss could be altered by varying the volume and rate of the injection. The loss of granule cells led to a shrinkage of the molecular layer and to a reactive gliosis. The lesion also caused an increase in the density of AChE and Timm staining in the molecular layer above the lesion. Although the increased density of AChE and Timm staining may have been due in part to the shrinkage of the molecular layer, part was due to the growth of inputs in response to the loss of granule cells and/or to the axotomy of the input terminals. The changes seen in the molecular layer above the lesion site ended abruptly at the margins of the lesion and the adjacent molecular and granule cell layers appeared normal.

Acetylcholinesterase↗
PubMed1989

Human cardiolipin as the antigen in an ELISA to detect anticardiolipin antibodies.

Human cardiolipin was purified from cadaver heart tissue and used as the antigen in an enzyme-linked immunoassay (ELISA) for anticardiolipin antibodies. The correlation between assays using human and bovine cardiolipin was r = 0.90. Of the lupus anticoagulant positive patients 88% had antibodies to the human antigen and 75% had antibodies to the bovine antigen. Six of 45 samples contained antibodies which only reacted with the human antigen. All six samples remained positive when retested with a different human cardiolipin preparation and were negative when tested against a preparation of sheep cardiolipin. These studies suggest that there was increased specificity when human cardiolipin was used as the phospholipid antigen.

Animals↗