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Biomedical subjects

M Wilson

Publications and source records attributed to M Wilson.

At least 685 records · Page 38Linked to original sources
PubMed1979

Laminaria use in midtrimester abortions induced by intra-amniotic prostaglandin F2alpha with urea and intravenous oxytocin.

A laminaria tent was used as an adjunct during midtrimester abortion to attempt to shorten the injection-abortion interval without adversely affecting the frequency of infection, hemorrhage, failed abortion, or cervical laceration. Eighty patients, between 14 and 20 weeks' gestation and desiring pregnancy termination, were randomized into three groups. Abortion was initiated by an intra-amniotic infusion of 20 mg of prostaglandin F2alpha and 80 gm of hyperosmolar urea in Ringer's lactate (135 ml total volume), followed by oxytocin infused intravenously at 333 mU/min. Group I (N = 28) received no additional therapy; Group II (N = 23) had laminaria placed at the time of the abortifacient injection and removed 4 hours later; Group III (N = 29) had laminaria placed 4 hours prior to inejction and removed at the time of injection. The injection-abortion intervals in these three groups were 17.76, 20.80, and 12.96 hours, respectively. This study illustrates that a laminaria tent palced 4 hours prior to injection is significantly more effective than a laminaria tent placed at the time of injection, and produces a shorter mean injection-abortion interval than that in patients receiving no laminaria. Furthermore, laminaria augmentation results in no demonstrable increase in the frequency of serious complications.

Abortifacient Agents↗
PubMed1979

The eye of the soldier beetle Chauliognathus pulchellus (Cantharidae).

The soldier beetle eye is unusual in having large optically isotropic corneal cones which project inwards from a thick isotropic cornea. Refraction is mainly at the corneal surface. Calculation shows that the first focal plane is near the tip of the cone, from which the optical pathway continues as a crystalline tract. At the distal end of the crystalline tract, 3 micrometer in diameter, the four cone cells enclose the proximal tip of the corneal cone; at the proximal end they enclose the distal tip of a long fused rhabdom rod. The eye is remarkable in that there are two classes of retinula cells; four cells contribute to the long thin axial rhabdom, 2 micrometer in diameter and 120 micrometer long, and the other four cells form two rounded rhabdoms, 10 x 4 micrometer in cross-section and 20 micrometer deep, which lie to one side of the optical axis. The physiological properties of individual retinula cells were measured by intracellular recording. The retinula cells are of three spectral types with peaks near 360, 450 and 520--530 nm. Except by the criterion of spectral sensitivity, the retinula cells sampled could not be sorted into more than one class. The measured value of the acceptance angle, near 3 degrees in the dark-adapted state, is consistent with the hypothesis that all sampled cells were of the anatomical type that participate in the central rhabdom rod. A calculation of the theoretical field size of individual retinula cells from measurments of refractive index and lens dimensions predicts that cells which participate in the central rhabdom will have acceptance angles near 3 degrees. The conclusion, therefore, is that only one anatomical type of cell has so far been sampled.

Adaptation, Physiological↗
PubMed1979

Hormones and the lung. II. Immunohistochemical localization of thyroid hormone binding in type II pulmonary epithelial cells clonally-derived from adult rat lung.

The type II pulmonary epithelial cell is the recognized state of surfactant synthesis and storage. Results of recent studies indicate that the thyroid hormones, triiodothyronine (T3) and thyroxine (T4), may be important regulators of surfactant production and/or release. Direct and indirect immunofluorescence techniques were used in an attempt to demonstrate binding of T3 and T4 in monolayer cultures of isolated type II cells. These cultured epithelial cells are clonally-derived from adult rat lung, retain a diploid karyotype through 35 population doublings in vitro, contain granular inclusions (lamellar bodies) in the perinuclear cytoplasm, and synthesize phosphatidylcholine via the CDP-choline pathway. In isolated type II cells, either of two fluorescent patterns was observed: (a) nuclear fluorescence accompanied by a reticular perinuclear network; or (b) diffuse cytoplasmic accumulations with concentrations around perinculear cytoplasmic inclusions. Ultrastructurally these inclusions had the typical appearance of lamellar bodies. Histochemical studies demonstrated that these inclusions contained surfactant-associated nonspecific esterases and stained with Nile blized markers for pulmonary surfactant indicate that these inclusions are indeed lamellar bodies, the putative sites of surfactant synthesis and/or storage. These findings suggest that the type II pulmonary epithelial cell contains specific binding sites for thyroid hormones, and support the hypothesis that thyroid hormones are regulators of surfactant metabolism.

Animals↗
PubMed1979

Middle temporal cortical visual area and visuospatial function in Galago senegalensis.

Bushbabies with lesions restricted to the middle temporal (MT) area and animals with larger extrastriate lesions including area MT were compared with normal control animals on test of visuospatial localization and discrimination learning. Ablation of area MT was sufficient to produce impairments in directing behavior appropriately on the basis of visuospatial cues. Extension of the lesion into areas 18 and 19 produced more profound deficits. Retardation in learning a stripe discrimination problem was correlated with the extent of damage to the geniculostriate system. It is hypothesized that area MT is important in achieving and maintaining fixation on a target whereas cortical areas 18 and 19 are necessary for establishing the location of stimulation in visual space.

Animals↗
PubMed1979

A forced-choice procedure to detect feigned or exaggerated hearing loss.

A forced-choice technique which may be used to confirm the existence of a non-organic hearing loss is described. Evidence is presented which shows that although this technique is not infallible it can in many cases unmask attempts to simulate or exaggerate a hearing loss. Supplementary tests using conventional audiometry demonstrated that persons with normal hearing can consistently feign a bilateral hearing loss.

Hearing Loss↗
PubMed1979

A new screening system for nonsteroidal anti-inflammatory drugs based upon inhibition of chemiluminescence produced from human cells (granulocytes).

A new screening system for nonsteroidal anti-inflammatory drugs that involves use of human phagocytic cells has been developed in which chemiluminescence measurement is used. Luminol-dependent chemiluminescence is measured after the addition of opsonized (coated with antibodies and complement) zymosan particles to human granulocytic leukocytes in the presence or absence of drugs. Of all the compounds tested, indomethacin was the most potent in blocking chemiluminescence, with measurable inhibitory activity at 5 mumol/L. The order of inhibitory potency at 0.1 mmol/L and in the presence of Ca2+ and Mg2+ was indomethacin greater than sodium salicylate greater than fenoprofen Ca greater than tolmetin greater than naproxen greater than ibuprofen. It is likely that the active compound itself must be added to the system because aspirin did not inhibit chemiluminescence, whereas its metabolite, sodium salicylate, was markedly inhibitory. Dexamethasone and methylprednisolone also did not inhibit chemiluminescence. The drugs that inhibit chemiluminescence are also known inhibitors of prostaglandin synthase (cyclooxygenase portion).

Anti-Inflammatory Agents↗
PubMed1978

The unit structure of the locust compound eye.

1. The ommatidium or functional unit of the locust compound eye comprises a compound corneal lens, 4 cone cells, 2 primary pigment cells, 16 secondary pigment cells and 8 retinula cells. 2. All retinula cells run the entire length from the cone to the basal lamina, although two, called the proximal cells, only contribute to the lowest third of the rhabdom, and one of either cell 6 or cell 7 on our arbitrary numbering system forms its axon one third the way up the ommatidium. 3. 84% of the 417 ommatidia examined had five cone cell processes. The position of three cone cell processes (cone threads) is almost invariable with respect to numbered retinula cells but the remaining threads can take any of three intercellular locations. 4. The position of these threads correlates with the number of the cell distally displaced from the rhabdom. We suggest that cone thread position in the developing ommatidium determines some features of retinula cells and we propose a simple model to account for this.

Animals↗
PubMed1978

Oligonucleotides in heterogeneous nuclear RNA: similarity of inverted repeats and RNA from repetitious DNA sites.

A comparison has been made by oligonucleotide analysis of three fractions of HeLa cell hnRNA: (1) the "snap-back" fraction (ds-hnRNA, 5% of the total); (2) the fraction that self-anneals during prolonged incubation (25% of total); and (3) the fraction that hybridizes most rapidly to an excess of HeLa cell DNA (rep-hnRNA, 10% of the total). T1 fingerprints of each of these hnRNA fractions were similar to one another and featured the largest T1 oligonucleotides of known sequence previously isolated from ds-hnRNA (Robertson, H.D., et al. (1977) J. Mol. Biol. 115, 571--590; Jelinek, W. (1977 J. Mol. Biol. 115, 591--602). When hybridized to DNA either in solution or immobilized on filters, the isolated ds-hnRNA and the rep-hnRNA fractions showed similar hybridization kinetics in the COt range of "intermediate" repetitive DNA sequences; the ds-hnRNA and the rep-hnRNA also self-annealed to equal extents in the absence of any DNA. DNA of all buoyant density classes contained the T1 oligonucleotides diagnostic of the ds-hnRNA and the rep-hnRNA. While hnRNA is rich in inverted repeated sequences, cytoplasmic mRNA contains far fewer such sequences.

Base Sequence↗
PubMed1978

Hypertension treated by salt restriction.

31 patients with a diastolic blood-pressure between 95 and 109 mm Hg have been treated for two years with a regimen involving a moderate restriction of salt in the diet. The results are compared with those in a control group and in a drug-treated group. Salt restriction has reduced the diastolic blood-pressure by 7.3+/-1.6 mm Hg, a result similar to that in patients treated with antihypertensive drugs. In the untreated group the diastolic blood-pressure rose by 1.8+/-1.1 mm Hg. Most patients did not achieve the desired amount of salt restriction and a stricter adherence to the diet might have caused further falls in blood-pressure. Excessive salt intake is probably a major cause of the epidemic of hypertension in "civilised" countries and a reduction in salt intake may help to control the epidemic. In persons with a diastolic blood-pressure between 90 and 105 mm Hg salt restriction should be tried before drugs.

Blood Pressure↗
PubMed1978

Naloxone has no effect on nitrous oxide anesthesia.

It has been reported that naloxone antagonizes general anesthesia in rats when the tail clamp is used as a painful stimulus to assess anesthesia. The authors' hypothesis is that this antagonism is to the analgesic component of anesthesia only, and that anesthesia assessed by a non-painful stimulus would not be antagonized by naloxone. Therefore, the anesthetic potency of nitrous oxide in mice was measured using loss of the righting reflex as a non-painful stimulus. Naloxone, 2 and 16 mg/kg, intraperitoneally, failed to antagonize nitrous oxide anesthesia measured 14--39 min after injection. Thus, 19 min after injection of naloxone, 2 mg/kg, the nitrous oxide ED50 was 1.25 +/- 0.0600 atm (n = 35), compared with 1.19 +/- 0.059 atm (n = 35) after injection of saline solution (control). Following naloxone, 16 mg/kg, the nitrous oxide ED50 was 1.18 +/- 0.059 atm (n =35), compared with 1.22 +/- 0.059 atm (n = 35) for saline solution. At neither dose of naloxone was the ED50 different from the control ED50, a finding that supports the author's hypothesis.

Anesthesia, Inhalation↗
PubMed1978

Immunohistochemical localization of thyroid hormone in rat thyroid gland.

Direct and indirect immunofluorescence techniques were used to localize the thyroid hormones triidothyronine (T3) and thyroxine (T4) in adult rat thyroid gland. Optimum dilutions of the antisera were established and four tissue fixatives were investigated for usefulness in this technique. Use of antibodies specific for either T3 or T4 resulted in brilliant fluorescence in the colloid pools and apical cytoplasm of follicular cells. In all cases, the adjacent parathyroid gland was devoid of fluorescence. This report demonstrates that these dipeptide hormones can be localized by using immunofluorescence techniques.

Animals↗