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Biomedical subjects

V King

Publications and source records attributed to V King.

At least 37 records · Page 2Linked to original sources
PubMed1996

Neuronal connections of orbital cortex in rats: topography of cortical and thalamic afferents.

The cortical and thalamic afferent connections of rat orbital cortex were investigated using fluorescent retrograde axonal tracers. Each of the four orbital areas has a distinct pattern of connections. Corticocortical connections involving the ventral and ventrolateral orbital areas are more extensive than those of the medial and lateral orbital areas. The medial orbital area has cortical connections with the cingulate, medial agranular (Fr2) and posterior parietal (PPC) cortices. The ventral orbital area has connections with the cingulate area, area Fr2, secondary somatic sensory area Par2, PPC, and visual areas Oc2M and Oc2L. The ventrolateral orbital area (VLO) receives cortical input from insular cortex, area Fr2, somatic sensory areas Par1 and Par2, PPC and Oc2L. The lateral orbital area has cortical connections limited to the agranular and granular insular areas, and Par2. Thalamic afferents to the four orbital fields are also topographically organized, and are focused in the submedial and mediodorsal nuclei. The ventrolateral orbital area receives input from the entirety of the submedial nucleus, whereas the other orbital areas receive input from its periphery only. Each orbital area is connected with a particular segment of the mediodorsal nucleus. The medial orbital area receives its principal thalamic afferents from the parataenial nucleus, the dorsocentral portion of the mediodorsal nucleus, and the ventromedial portion of the submedial nucleus. The ventral orbital area receives input from the lateral segment of the mediodorsal nucleus, the rostromedial portion of the submedial nucleus, and the central lateral nucleus. Thalamic afferents to the ventrolateral orbital area arise from the entirety of the submedial nucleus and from the lateral segment of the mediodorsal nucleus. The lateral orbital area receives thalamic afferents from the central segment of the mediodorsal nucleus, the ventral portion of the submedial nucleus, and the ventromedial nucleus. The paraventricular, ventromedial, rhomboid and reuniens nuclei also provide additional input to the four orbital areas. The connections of the ventrolateral orbital area are interpreted in the context of its role in directed attention and allocentric spatial localization. The present findings provide anatomical support for the view that areas Fr2, PPC and VLO comprise a cortical network mediating such functions.

Animals↗
PubMed1996

Circadian regulation of Fos-like expression in the brain of the blow fly Calliphora vicina.

Expression of Fos-like immunoreactivity (FOS-lir) was examined in the brains of the blow fly Calliphora vicina for evidence of circadian regulation by photic stimuli. Fos-lir in various parts of the brain was investigated as a function of light and time of day. Immunohistochemistry demonstrated that photic stimuli have an inductive effect on c-fos expression in the various parts of the brain, but only in the neurons of the pars intercerebralis did the clear photic induction of c-fos expression occur at times when light was capable of phase-shifting circadian locomotor activity rhythms. This suggests that the c-fos gene may play a role in the photic pathway for circadian entrainment and that these neurons may be involved in the transduction of photic signals. Whether changes in c-fos expression are essential components of this pathway remains to be determined.

Animals↗
PubMed1996

Improved dose distribution in the brain by collimator rotation.

Because the head slopes both in the sagittal and lateral directions, the brain is one of the anatomical areas which could benefit by the use of 3-dimensional compensators. The fabrication of 3-dimensional compensators is an expensive and complex task, and as such, not widely used. A standard wedge is often employed to compensate for skull curvature when treating a partial brain area, with the heel of the wedge placed either superior or lateral. This usually results in areas of over- and under dosage in the planning target volume. However, by rotating the collimator 45 degrees while using a standard wedge, with the heel placed superior-lateral, the dose distribution can be significantly improved.

Brain↗
PubMed1996

Effects of intramuscular or interpleural administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy.

OBJECTIVE: To evaluate effects of interpleural or IM administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy. DESIGN: Experimental trial. ANIMALS: 18 healthy dogs. PROCEDURE: Dogs underwent median sternotomy and were randomly assigned to groups of 6 dogs each. Group-A dogs were given morphine (1.0 mg/kg of body weight) i.m.; group-B dogs were given 0.5% bupivacaine (1.5 mg/kg) interpleurally; and group-C dogs were given morphine (1.0 mg/kg) interpleurally. Heart rate; systolic, diastolic, and mean arterial pressures; rectal temperature; pain score; and arterial blood gas partial pressures were measured and pulmonary function testing was performed immediately after extubation (time 0) and up to 48 hours later. Serum cortisol and morphine concentrations were measured at time 0 and up to 12 hours after surgery. RESULTS: There was a significant decrease in pH, PaO2, mean oxygen saturation of hemoglobin, and dynamic compliance; and a significant increase in PaCO2, alveolar-arterial difference in partial pressure of oxygen, pulmonary resistance, and work of breathing for dogs in all groups after surgery. Serum cortisol concentrations were significantly increased, compared with preoperative values, in all dogs. Serum cortisol concentrations were significantly higher in group-B dogs between 3 and 5 hours after surgery, compared with group-A dogs. CONCLUSIONS: Median sternotomy was associated with significant alterations in pulmonary function. Effects of interpleural administration of bupivacaine and morphine were similar to effects of i.m. administration of morphine.

Analgesics, Opioid↗
PubMed1995

Chronic bicipital tenosynovitis in dogs: 29 cases (1985-1992).

Medical records of 23 dogs with unilateral and 3 dogs with bilateral chronic bicipital tenosynovitis were reviewed. Mean age of affected dogs was 4.6 years (SD, 2.0 years), and mean body weight was 32.6 kg (SD, 14.5 kg). Neither a breed nor a gender predilection was detected. All dogs had a history of intermittent or progressive weight-bearing lameness that became worse after exercise. Mean duration of lameness prior to medical or surgical treatment was 6.5 months (range, 0.25 to 24 months). In all dogs, signs of pain were evident during palpation of the biceps tendon within the intertubercular groove. Radiography revealed sclerosis or osteophytosis of the intertubercular groove in all 29 shoulder joints. Mild degenerative joint disease was evident radiographically in 17. Arthrography was performed in 12 joints, and in 11 there were irregularities of or filling defects along the biceps tendon. Arthrocentesis was performed on 17 joints; 14 synovial fluid samples had cytologic abnormalities consistent with degenerative joint disease. Medical treatment, consisting of injection of methylprednisolone acetate into the biceps tendon and its synovial sheath, was attempted in 21 of the 29 affected shoulder joints. Surgery, which consisted of tenodesis of the biceps tendon, was attempted in 14 joints; 8 of these had not been treated medically; the remaining 6 had poor results following medical treatment. Gross and histologic findings consistent with chronic bicipital tenosynovitis were observed in all 14 joints in which surgery was performed. Seventeen of the medically treated shoulders were available for clinical evaluation, and results were excellent or good in 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Reflective midwifery practice: facilitating midwives' practice insights using a distance education reflective practitioner model.

A study was undertaken to evaluate a reflective practitioner model with midwives, who self-selected into the project when they were studying the Bachelor of Health Science (Nursing) unit NR278, Advanced Nursing Practice, Midwifery. The theoretical assumptions that influenced the research were those forwarded by Schon (1983) and Boud, Keogh and Walker (1985), who argued that practitioners are often unaware of the sophisticated knowledge they have regarding the intricacies of their practice, but that this personal knowledge can be make explicit through reflective processes. The aim of the study was to research the use of a distance education reflective practitioner process that encouraged midwives to examine their practice with a view to making changes where necessary. All the research objectives were met to some extent, although each experience of the research process was particular to the individual participant. Analysis consisted of: interpretation of the participant's insights into their individual experiences; the researcher's interpretations of participant's experiences; and collective themes arising out of the research. This paper concentrates mainly on the participant's insights into their individual experiences of practising midwifery, using a reflective practitioner model.

Education, Nursing, Baccalaureate↗
PubMed1995

Effect of glucocorticoids on serum osteocalcin concentration in horses.

The effects of dexamethasone (0.2 mg/kg of body weight; IV, IM, and PO) and methylprednisolone acetate (120 mg given intra-articularly) on serum osteocalcin and cortisol concentrations were studied in 6 horses. Serum osteocalcin and cortisol concentrations were serially monitored after each treatment. A significant (P < 0.05) decrease in serum osteocalcin and cortisol concentrations was observed from 12 to 24 and 2 to 48 hours, respectively, after IV and IM administrations of dexamethasone. Serum osteocalcin and cortisol concentrations were significantly decreased from 6 to 48 and 3 to 72 hours, respectively, after oral administration. In contrast, a change in serum osteocalcin concentration was not detected after intra-articular administration of methylprednisolone. Oral, IV, or IM treatment with 0.2 mg of dexamethasone/kg caused a decrease in serum osteocalcin concentration in horses.

Animals↗
PubMed1994

Rat posterior parietal cortex: topography of corticocortical and thalamic connections.

Anatomical and functional findings support the contention that there is a distinct posterior parietal cortical area (PPC) in the rat, situated between the rostrally adjacent hindlimb sensorimotor area and the caudally adjacent secondary visual areas. The PPC is distinguished from these areas by receiving thalamic afferents from the lateral dorsal (LD), lateral posterior (LP), and posterior (Po) nuclei, in the absence of input from the ventrobasal complex (VB) or dorsal lateral geniculate (DLG) nuclei. Behavioral studies have demonstrated that PPC is involved in spatial orientation and directed attention. In the present study we used fluorescent retrograde axonal tracers primarily to investigate the cortical connections of PPC, in order to determine the organization of the circuitry by which PPC is likely to participate in these functions, and also to determine how the topography of its thalamic connections differs from that of neighboring cortical areas. The cortical connections of PPC involve the ventrolateral (VLO) and medial (MO) orbital areas, medial agranular cortex (area Fr2), portions of somatic sensory areas Par1 and Par2, secondary visual areas Oc2M and Oc2L, auditory area Te1, and retrosplenial cortex. The secondary visual areas Oc2L and Oc2M have cortical connections which are similar to those of PPC, but are restricted within orbital cortex to area VLO, and within area Fr2 to its caudal portion, and do not involve auditory area Te1. The cortical connections of hindlimb cortex are largely restricted to somatic sensory and motor areas. Retrosplenial cortex, which is medially adjacent to PPC, has cortical connections that are prominent with visual cortex, do not involve somatic sensory or auditory cortex, and include the presubiculum. We conclude that PPC is distinguished by its pattern of cortical connections with the somatic sensory, auditory and visual areas, and with areas Fr2, and VLO/MO, in addition to its exclusive thalamic connectivity with LD, LP and Po. Because recent behavioral studies indicate that PPC, Fr2 and VLO are involved in directed attention and spatial learning, we suggest that the interconnections among these three cortical areas represent a major component of the circuitry for these functions in rats.

Animals↗
PubMed1994

Thyroidectomy does not affect the daily or free-running rhythms of plasma melatonin in European starlings.

Thyroidectomy results in the suppression of reproductive photoperiodic responses in starlings. Could this be a consequence of an effect on perception of daylength or on circadian pacemakers? Daily changes in plasma melatonin concentrations were monitored in intact and thyroidectomized starlings held in long days (LD 16:8) and short days (LD 8:16), and in intact and thyroidectomized starlings allowed to free-run in constant darkness from long days or short days. In long days and short days, melatonin was low during the light period and high during darkness. There was no difference between intact and thyroidectomized birds. In free-running birds, the melatonin profile of the preceding long day or short day was retained during the first day of constant darkness, with peak levels occurring at the same time they did during the light-dark cycles. Again there was no difference between intact and thyroidectomized birds. These data demonstrate that either the photoreceptive and circadian mechanisms driving melatonin secretion are independent of those concerned with reproductive photoperiodic responses, or that thyroidectomy affects reproduction "downstream" from the photoreceptive-circadian apparatus.

Animals↗
PubMed1993

Effect of host lineage on the virulence of Campylobacter jejuni/coli in the chick embryo model.

The chorioallantoic membrane (CAM) inoculated chick embryo model was used to study the effect of host lineage on the virulence of Campylobacter jejuni and Campylobacter coli. LD50 values were used to compare the susceptibilities of chick embryos from eight inbred chicken lines to infection by four strains of C. jejuni and one strain of C. coli. Differences in susceptibility were found between inbred chicken lines. These were shown not to be due to maternal antibody status, nor transfer of antibody to the developing embryo. Susceptibility to infection was also found to vary according to the Campylobacter strain used. These results indicate that both the bacterial strain and host lineage of the chicken line used affect resistance to infection in the CAM inoculated chick embryo model.

Allantois↗
PubMed1993

Epidermal growth factor stimulates vascular endothelial growth factor production by human malignant glioma cells: a model of glioblastoma multiforme pathophysiology.

Hypervascularity, focal necrosis, persistent cerebral edema, and rapid cellular proliferation are key histopathologic features of glioblastoma multiforme (GBM), the most common and malignant of human brain tumors. By immunoperoxidase and immunofluorescence, we definitively have demonstrated the presence of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFr) in five out of five human glioma cell lines (U-251MG, U-105MG, D-65MG, D-54MG, and CH-235MG) and in eight human GBM tumor surgical specimens. In vitro experiments with glioma cell lines revealed a consistent and reliable relation between EGFr activation and VEGF production; namely, EGF (1-20 ng/ml) stimulation of glioma cells resulted in a 25-125% increase in secretion of bioactive VEGF. Conditioned media (CM) prepared from EGF-stimulated glioma cell lines produced significant increases in cytosolic free intracellular concentrations of Ca2+ ([Ca2+]i) in human umbilical vein endothelial cells (HUVECs). Neither EGF alone or CM from glioma cultures prepared in the absence of EGF induced [Ca2+]i increases in HUVECs. Preincubation of glioma CM with A4.6.1, a monoclonal antibody to VEGF, completely abolished VEGF-mediated [Ca2+]i transients in HUVECs. Likewise, induction by glioma-derived CM of von Willebrand factor release from HUVECs was completely blocked by A4.6.1 pretreatment. These observations provide a key link in understanding the basic cellular pathophysiology of GBM tumor angiogenesis, increased vascular permeability, and cellular proliferation. Specifically, EGF activation of EGFr expressed on glioma cells leads to enhanced secretion of VEGF by glioma cells. VEGF released by glioma cells in situ most likely accounts for pathognomonic histopathologic and clinical features of GBM tumors in patients, including striking tumor angiogenesis, increased cerebral edema and hypercoagulability manifesting as focal tumor necrosis, deep vein thrombosis, or pulmonary embolism.

Brain Neoplasms↗
PubMed1993

Single-dose, randomized, double-blind, double-dummy cross-over comparison of extradural and i.v. clonidine in chronic pain.

We studied 10 patients with chronic back pain who had claimed benefit with a previous extradural dose of clonidine 150 micrograms combined with local anaesthetic. We compared a single dose of clonidine 150 micrograms given by either the extradural or i.v. route in a double-blind, randomized, double-dummy and cross-over fashion, with 80% power to detect a difference in the analgesic effect of the two routes. Pain intensity, pain relief, adverse effects, mood, sedation and vital signs were assessed by a nurse observer. I.v. clonidine produced significantly (P < 0.04) greater analgesia than extradural clonidine in one of the five analgesic outcome measures. Clonidine given by either route produced statistically significant sedation and significant decreases in arterial pressure and heart rate. In this study, extradural clonidine had no significant clinical advantages compared with i.v. clonidine; clonidine 150 micrograms by either route produced a high incidence of adverse effects.

Adult↗
PubMed1993

A double-blind study of the effectiveness of low level laser treatment of rotator cuff tendinitis.

Thirty-five patients with rotator cuff tendinitis were randomly allocated to active (CB Medico Master III 830 nm Ga As AL diode) laser or dummy laser treatment twice weekly for 8 weeks. Movement range, painful arc score, resisted movement score and responses to visual analogue scales for night pain, rest pain, movement pain and functional limitation were measured second weekly. All responses improved from baseline but there was no difference between the two groups. These results fail to demonstrate the effectiveness of laser therapy in rotator cuff tendinitis.

Adolescent↗
PubMed1992

Thalamocortical connections of rat posterior parietal cortex.

The neuronal connections of rat posterior parietal cortex (PPC) have been examined using retrograde fluorescent axonal tracers. We have found that PPC receives thalamic input predominantly from the lateral posterior and lateral dorsal nuclei, and not from the ventrobasal nucleus, which projects to the rostrally adjacent hindlimb cortex, or from the dorsal lateral geniculate nucleus, which projects to the caudally adjacent visual association area. PPC has reciprocal corticocortical connections with medial agranular cortex and orbital cortex; together, these three cortical areas may function as a network for directed attention in rats.

Afferent Pathways↗
PubMed1991

Experimental and clinical observations on hepatic cryosurgery for colorectal metastases.

Cryosurgery, using liquid nitrogen at -196 degrees C, was explored for treating colorectal liver metastases in an experimental study of rat colon cancer and in a clinical investigation of patients with unresectable liver tumors. The viability of rat colon cancer isografts showed that while two or three freeze-thaw cycles were 100% effective in controlling established isografts and preventing isograft take, one freeze-thaw cycle was suboptimal. In these animals cryosurgery was as effective as surgical resection in controlling established experimental liver metastases. Cryosurgery by operative liver exposure and intraoperative ultrasound monitoring were used to treat liver metastases from colorectal cancer in 24 patients. At a median follow-up of 2 years (range, 5 months to 5 years), seven patients (29%) are disease free, eight (33.5%) are alive with recurrent tumors, and nine (37.5%) have died. The patterns of failure were: remaining liver and extrahepatic sites, ten patients (59%); remaining liver only, six patients (35%); and extrahepatic only, one patient (6%). These data demonstrate that cryosurgery is a useful modality for treating unresectable primary and metastatic liver cancers. Addition of systemic adjuvant therapy may improve the tertiary failure following the control of liver metastases.

Adult↗
PubMed1991

Genomic investigation of phenotypic variation in Campylobacter jejuni flagellin.

Western blots of whole-cell sonicates of 10 different clones of a faecal isolate of Campylobacter jejuni 533 detected the expression of flagella antigens of either 59 or 62 kDa. Other antigenic proteins appeared identical both in the parent and all the clones. The mechanism for this phenotypic variation was studied using Southern blotting with a flagellin-specific gene probe and products of a polymerase chain reaction (PCR) using flagellin-gene primers. Restriction-enzyme digestion and Southern blotting did not detect any genomic rearrangements in the flagellin genes of the different phenotypes nor did restriction-enzyme analysis of the PCR products.

Base Sequence↗