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Biomedical subjects

A Hicks

Publications and source records attributed to A Hicks.

54 records · Page 3Linked to original sources
PubMed1987

The ripple phase of phosphatidylcholines: effect of chain length and cholesterol.

Saturated phosphatidylcholine (PC) bilayers display a rippled surface in the temperature region between the pre- and main transitions. Ripple repeat distance was measured from freeze-fracture electron micrographs. All of the lipids examined (C13PC to C16PC; C14C16PC and equimolar C14PC/C16PC) showed a bimodal distribution of ripple repeat distances with the two dominant values being in the ratio of 1:2. Within this series, chain length was a weak determinant of the actual repeat distance. The introduction of increasing concentrations of cholesterol eliminated the bimodal distribution and led to the appearance of a single distribution of increasing repeat distance and decreasing amplitude. Ripples disappeared above a cholesterol concentration of 15 mol%. These observations are discussed within the framework of a model which links the genesis of the ripples (vertical displacement of lipid molecules) to the trans-gauche isomerization known to occur at the pre-transition.

Chemical Phenomena↗
PubMed1984

Occurrence and frequency of subgroup I-6 spiroplasma in arthropods associated with old fields in Maryland and Virginia.

The Subgroup I-6 spiroplasma, "Maryland Flower Spiroplasma," originally discovered on fall flowers and subsequently recovered from a syrphid fly and a beetle triungulin, was isolated from two new fall flower hosts and from the guts of nine nectar-imbibing insect species. These data, together with lack of recovery of I-6 spiroplasma from foliage-feeding, plant-sucking, or flightless flower-associated insects, suggest that I-6 spiroplasma may infect and be disseminated by nectar- or pollen-foraging insects, and that the dynamics of maintenance will prove to be complex.

Animals↗
PubMed1982

The reliability of axis II of DSM-III.

The reliability of the diagnoses of axis II of DSM-III was examined by measuring the levels of agreement among three psychiatrists who independently examined the same patients in everyday clinical settings. The kappa coefficient levels were lower than those reported from the field trials.

Adolescent↗
PubMed1982

The paradoxical effect of a juvenile code change in Virginia.

The impact of a new state juvenile code on the processing of youth through one court locale was examined using an interrupted time-series design. The intent of the new code was to limit penetration of youth into the juvenile justice system. This locale, however, showed an increased number of youth going through to court despite no increase in the number of youth arrested. The importance of this paradoxical effect for local juvenile justice planners and court officials is discussed briefly.

Adolescent↗
PubMed1980

Car seat belts.

Explore the source record for details and available documents.

Accidents, Traffic↗
PubMedDate not supplied

Efficacy and acceptability of nedocromil sodium 2% and olopatadine hydrochloride 0.1% in perennial allergic conjunctivitis.

In this 2-week, randomized, crossover study, ophthalmic solutions of nedocromil sodium 2% and olopatadine hydrochloride 0.1% were compared for effectiveness and acceptability in 28 patients with perennial allergic conjunctivitis and previous olopatadine experience. Patients received nedocromil twice daily or olopatadine twice daily for 1 week, then were crossed over to the alternate medication for 1 week. Outcome measures were patient satisfaction (questionnaire), severity of ocular symptoms (daily diary scores), clinical signs (physician assessments), quality of life (questionnaire), and global assessments of effectiveness. Both medications were well accepted. Of the 28 patients, 16 (57.1%) would request a nedocromil prescription, 10 (35.7%) an olopatadine prescription (P = .157); 22 patients (78.6%) would recommend nedocromil to other allergy sufferers, while 18 (64.3%) would recommend olopatadine (P = .480). Light sensitivity scores were significantly lower with nedocromil (P = .0125); other symptom scores were comparable between medications. Both drugs significantly (P < .01) and comparably decreased erythema, conjunctival injection, and overall conjunctival signs from baseline. Comparable improvement also occurred in quality-of-life scores. Both physicians and patients judged nedocromil and olopatadine to be similarly effective in preventing signs and symptoms. Nedocromil sodium 2% is an effective treatment for perennial allergic conjunctivitis. Patients receiving olopatadine can be switched to nedocromil with no loss in efficacy or satisfaction, but with a reduction in cost.

Adolescent↗
PubMedDate not supplied

Nedocromil sodium in golfers with seasonal allergic conjunctivitis.

To evaluate nedocromil sodium 2% ophthalmic solution for the treatment of seasonal allergic conjunctivitis, 24 golfers with documented ragweed-pollen allergy instilled eyedrops twice daily for 4 days prior to golf-course intervention and 15 minutes before playing a round of golf during peak ragweed season. Ocular symptoms were scored at baseline (7 days before golfing), prior to instillation on the day of golf, and 30 minutes, and 1, 4, 8, and 12 hours after tee-off. Physician assessment was performed prior to tee-off, before tee-off on the ninth hole, and at the end of the 18th hole. Itching, burning, grittiness, tearing, redness, and light sensitivity were significantly decreased after nedocromil administration, as were erythema, edema, conjunctival hyperemia, and overall findings in the conjunctiva. Symptom severity scores fell approximately 30 minutes after instillation, with improvements persisting 8 and 12 hours after treatment. Most patients (92%) rated the treatment moderately or completely effective, and 83% were willing to continue its use. Physician assessments of effectiveness agreed with those of the patients. In this open-label study, nedocromil sodium eyedrops relieved the ocular symptoms of seasonal allergic conjunctivitis for up to 12 hours, well beyond a usual round of golf.

Adolescent↗
PubMedDate not supplied

Increase in syntaxin 1B mRNA in hippocampal and cortical circuits during spatial learning reflects a mechanism of trans-synaptic plasticity involved in establishing a memory trace.

It has long been proposed that the cellular and molecular mechanisms responsible for LTP may well involve the mechanisms that lead to the type of synaptic modification that occurs during learning. However, it is also known that a single memory trace is encoded in spatially distributed networks; implying that alterations of synaptic strength occur at multiple sites along circuits of connected cells. Recent evidence suggests that regulation of the gene encoding syntaxin 1B, a presynaptic protein involved in exocytosis, plays an important role in the mediation of trans-synaptic LTP, a candidate mechanism for the propagation of plasticity in neural circuits during learning. Using in situ hybridization to measure the mRNA levels at different time points after learning a spatial working or reference memory task, we show that expression of the gene encoding this protein in the hippocampal and corticoprefrontal circuits increases linearly with performance at a critical window of learning when rats are reaching between 75% and 100% of their maximal performance. No changes were observed during the early phases of learning or when rats where overtrained. The correlational analysis indicates that coordinated increases in syntaxin 1B expression occurs in hippocampal circuits during working memory and in more widespread hippocampocortical circuits during reference memory. These results suggest that a form of trans-synaptic plasticity mediated in part by regulation of the expression of syntaxin 1B may play an active role in configuring specific spatially distributed circuits during the laying down of memories.

Animals↗