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Biomedical subjects

S L Jones

Publications and source records attributed to S L Jones.

At least 163 records · Page 9Linked to original sources
PubMed1988

Chorionic villus sampling: experience with an initial 940 cases.

Of over 1000 patients referred to the Genetics & IVF Institute for chorionic villus sampling, 10% had an abnormal gestational sac at the time of initial presentation. Villus sampling could not be performed in 0.6% of cases, usually because of fibroids. Chorioamnionitis, probably related to the procedure, occurred in two patients (0.2%). The total fetal loss was 2.4%, which is not significantly different from the background fetal loss rate reported in normal pregnancies after eight weeks of gestation. The procedure-related loss was estimated as approximately 0.6%. The cytogenetic analysis routinely used was "direct" trophoblast karyotyping. There were no false-negative diagnoses. Trophoblastic mosaicism was observed in 1.3% of samples. Amniocentesis was performed in 3.5% of cases because of chorionic villus sampling failure, chorionic mosaicism, or elevated maternal serum alpha-fetoprotein (MSAFP) concentrations. Chorionic villus sampling was not associated with falsely elevated MSAFP levels at 15-18 weeks' gestation. Chorionic villus sampling has proved a safe and accurate prenatal diagnostic method associated with relatively low risk when performed by an experienced team, although additional amniocentesis will be necessary in a small percentage of pregnancies.

Adult↗
PubMed1987

Contribution of the site of heating to variability in the latency of the rat tail flick reflex.

The rat tail flick reflex is a commonly used assay of thermal nociception. Variability in the latency to respond due to the locus of tail heating was examined in spinalized (midthoracic) rats and evaluated retrospectively using data from two previously published studies. In all 3 sets of data, a significant relation was found between the proximal-distal site of heating on the tail and the latency of the tail flick reflex. Heating of the most distal sites resulted in shortest response latencies.

Animals↗
PubMed1987

Effect of spinal norepinephrine depletion on descending inhibition of the tail flick reflex from the locus coeruleus and lateral reticular nucleus in the rat.

The lateral reticular nucleus (LRN) and locus coeruleus-subcoeruleus (LC/SC), brainstem structures which overlap the A1 and A6 noradrenergic nuclei respectively, have been implicated in descending modulation of spinal nociceptive transmission. The present studies were designed to examine the role of norepinephrine (NE) in the mediation of inhibition of the nociceptive tail flick reflex produced by focal electrical stimulation in the LRN and LC/SC. Spinal NE was depleted by intrathecal administration of 6-hydroxydopamine (6-OHDA; 20 micrograms) and the threshold electrical stimulation in the LRN and the LC/SC necessary to inhibit the tail flick reflex in lightly pentobarbital-anesthetized rats was determined 9 and 14 days later. Despite a significant depletion (greater than 85%) of lumbar spinal cord NE content, there was no significant change in the tail flick inhibitory stimulation thresholds in the LRN or LC/SC. NE depletion did, however, potentiate the elevation in the inhibitory stimulation threshold in the LRN produced by intrathecal administration of the alpha 2-adrenoceptor antagonist, yohimbine, suggesting that upregulation of spinal adrenoceptors had occurred following 6-OHDA treatment. Adrenoceptor up-regulation was examined quantitatively by characterizing the dose-dependent antinociceptive potency of the selective alpha 2-adrenoceptor agonist clonidine 3, 7, 10, and 14 days following 6-OHDA administration, and analysis of [3H]rauwolscine binding to lumbar spinal cord 9 days following administration of the neurotoxin. The development of supersensitivity, defined as the leftward parallel shift of the dose-response curves for clonidine administered intrathecally, corresponded to the time course of NE depletion following 6-OHDA treatment on the days tested. Binding of [3H]rauwolscine to lumbar spinal cord revealed an elevation in the estimated Bmax without a change in the estimated Kd of the high affinity binding component 9 days following 6-OHDA administration. This study demonstrates that spinal adrenoceptor denervation supersensitivity develops rapidly following intrathecal administration of 6-OHDA and compensates for the selective destruction of spinal noradrenergic nerve terminals. Thus, the absence of effect of NE depletion on the tail flick inhibitory stimulation threshold in the LRN and the LC/SC does not argue against the hypothesis that spinopetal NE-containing neurons in these brainstem loci are involved in modulation of spinal nociceptive transmission.

Animals↗
PubMed1987

Stimulation-produced descending inhibition from the periaqueductal gray and nucleus raphe magnus in the rat: mediation by spinal monoamines but not opioids.

Focal electrical stimulation in the midbrain periaqueductal gray (PAG) or medullary nucleus raphe magnus (NRM) inhibits spinal nociceptive transmission and nociceptive reflexes. The purpose of this study was to evaluate, in lightly pentobarbital-anesthetized rats, the spinal neurotransmitter(s) mediating descending inhibition of the nociceptive tail-flick (TF) reflex produced by focal electrical stimulation in the PAG or NRM. To characterize the neurotransmitter(s) mediating inhibition of the TF reflex, selective pharmacologic antagonists were administered into the lumbar intrathecal space. Stimulation thresholds in the PAG or NRM for inhibition of the TF reflex were established and the effects of intrathecally administered phentolamine, yohimbine, prazosin, methysergide (15 micrograms initially, 30 micrograms cumulative) or naloxone (10 micrograms initially, 20 micrograms cumulative) on TF inhibitory thresholds determined. Phentolamine, yohimbine and methysergide increased the intensity of stimulation in the PAG and the NRM for inhibition of the TF reflex; prazosin and naloxone had no effect. Descending inhibition produced by focal electrical stimulation in the PAG or NRM is mediated in part by spinal serotonergic and/or alpha 2-adrenergic receptors. Naloxone was administered both intrathecally and intravenously; however, a role for opioid receptors in descending inhibition from the midbrain or medulla was not found.

Animals↗
PubMed1987

The effect of feeding endophyte infected tall fescue seed on reproductive performance in female rats.

Female Sprague-Dawley rats (Rattus norvegicus) were randomly assigned to diets containing mixtures of rat chow and tall fescue (Festuca arundinacea) seed with 0, 5, 10, 20 and 40% infection levels of Acremonium coenophialum to assess the effect of the diets on the reproductive potential of rats. Rats fed 40% infected seed had decreased body weight, decreased mean percent body weight of uteri, failed to maintain normal estrous cycles and were unable to become pregnant. Animals fed a diet of 20% infected fescue seed had extended estrous cycles. There were no significant differences among the 0, 5 and 10% dietary treatments.

Acremonium↗
PubMed1987

Spinal pathways mediating tonic, coeruleospinal, and raphe-spinal descending inhibition in the rat.

1. The contribution of midline medullary bulbospinal neurons to descending inhibition from the locus coeruleus (LC) and the funicular trajectories of coeruleo- and raphe-spinal fibers mediating inhibition of spinal nociceptive transmission were examined in different experiments. Extracellular recordings of lumbar dorsal horn neurons were made in deeply pentobarbital-anesthetized, paralyzed rats. All units studied responded to electrical stimulation of the ipsilateral tibial nerve at intensities supramaximal to activate A-alpha-delta- and C-fibers and to mechanical and heat (50 degrees C) stimuli of the glabrous skin of the ipsilateral hind foot. Parallel studies were done in lightly pentobarbital-anesthetized rats utilizing the nociceptive tail-flick (TF) reflex. 2. To examine the contribution of bulbospinal neurons in the nucleus raphe magnus (NRM) to descending coeruleospinal inhibition, lidocaine microinjections were made into the NRM to produce a time-limited, reversible block. Lidocaine microinjections into the NRM effectively blocked NRM stimulation-produced inhibition of the TF reflex (prelidocaine stimulation thresholds were increased two to three times), but did not affect stimulation-produced inhibition from the LC. 3. In parallel electrophysiological studies, stimulation in the NRM inhibited heat-evoked dorsal horn unit activity to 31% of control, whereas stimulation in the LC/SC inhibited heat-evoked activity of the same units to 30% of control. Following NRM lidocaine microinjections, stimulation at the same intensity in the NRM no longer inhibited heat-evoked activity (93% of control), confirming the efficacy of the lidocaine block. LC stimulation-produced inhibition, however, was not affected by blockage of the NRM; heat-evoked unit activity was inhibited by LC stimulation to 39% of control. 4. The effects of ipsilateral and bilateral ventrolateral funiculus (VLF) lidocaine microinjections on spontaneous and heat-evoked unit activity were examined in other experiments. Spontaneous activity increased following ipsilateral VLF lidocaine microinjections for 13/18 units; decreases and no change in spontaneous activity were observed for three and two units, respectively. Heat-evoked unit activity was increased significantly following ipsilateral VLF lidocaine microinjections.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Improving compliance for asthmatic patients visiting the emergency department using a health belief model intervention.

The sample included 74 asthmatic patients presenting to an emergency department with an acute asthmatic attack. The purposes of the study were: to assess demographic and situational variables associated with compliance, and to test the impact of a Health Belief Model (HBM) intervention to increase compliance. Compliance was operationalized as making and/or keeping a follow-up referral appointment for the patient's asthmatic condition. Demographic and situational variables associated with compliance included age, sex, marital status, previous treatment experience, seriousness of the asthmatic condition, and need for child care. Most important, the HBM intervention was very effective in increasing compliance in both making and keeping a follow-up referral appointment.

Adolescent↗
PubMed1987

Maternal serum alpha-fetoprotein screening after chorionic villus sampling.

To evaluate whether maternal serum alpha-fetoprotein (MSAFP) concentrations at 15-18 weeks' gestation are influenced by chorionic villus sampling performed three to ten weeks earlier, MSAFP levels were determined for 417 postchorionic villus sampling patients and 967 control subjects without previous chorionic villus sampling. Statistical comparison of the medians, distributions, and proportions above defined multiples of the median demonstrated no significant difference between the two populations. These results indicate that MSAFP screening in postchorionic villus sampling patients should be reliable and that values may be interpreted using criteria similar to those used for the general population.

Adult↗
PubMed1987

Outpatient in vitro fertilization using transvaginal ultrasound-guided oocyte retrieval.

Of 80 patients who initiated in vitro fertilization cycles in an integrated outpatient facility, 61 had oocyte retrievals performed under local anesthesia with ultrasound-guided transvaginal aspiration of ovarian follicles. Ten patients conceived, all in the group of 49 who had human chorionic gonadotropin (hCG)-timed retrievals. Our results indicate that in vitro fertilization can be performed to a high standard with this method, with excellent patient acceptance and reduced cost without general anesthesia, laparoscopy, or in-hospital setting.

Adult↗
PubMed1987

Improving follow-up among hypertensive patients using a health belief model intervention.

Seventy-two hypertensive patients visiting an emergency department (ED) were randomized to one of four study groups to test the effect on compliance of a health belief model (HBM) intervention: a control group, a group receiving an HBM clinical intervention in the ED, a group receiving an HBM telephone call two days after the ED visit, and a combination clinical plus telephone intervention. Patients receiving any HBM intervention were 50% more likely to make, and 47% more likely to keep, a follow-up referral appointment than control group patients.

Adolescent↗
PubMed1986

Cryopreservation of human lymphocytes for assessment of lymphocyte subsets and natural killer cytotoxicity.

Cryopreservation of lymphocytes has become increasingly important, especially when the cells are to be used in retrospective studies of selected and dwindling populations, such as A-bomb survivors. This report describes an efficient method for cryopreservation of human lymphocytes which does not significantly alter various immunological characteristics of these cells. The proportions of Leu-1+ cells (T cells), Leu-2a+ cells (suppressor-cytotoxic T cells), Leu-3a+ cells (helper-inducer T cells), HLA-DR+ cells, Mo2+ cells (monocytes), B1+ cells (B cells), and Leu-7+ cells (natural killer (NK) cells), as determined by monoclonal antibodies, were found to be stable following cryopreservation. NK cell activity against K-562 target cells showed a 40-60% decrease immediately after thawing, but recovered to approximate pre-freezing levels after preincubation for 18 h. Neither lymphocyte subsets nor cell viability significantly changed following preincubation after cryopreservation. However, the ratio of cells binding to K-562 cells increased after this preincubation and may account for the observed recovery of NK cell activity. NK cell activity remained relatively stable up to 14 months of storage which confirms that freezing damage depends on the freezing process rather than on the duration of cryopreservation.

Antibodies, Monoclonal↗