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Biomedical subjects

C Jennings

Publications and source records attributed to C Jennings.

At least 19 recordsLinked to original sources
PubMed2006

Dynamics of cylindrically converging precursor plasma flow in wire-array Z -pinch experiments.

This paper summarizes the present understanding of the processes leading to precursor column formation in cylindrical wire arrays on the 1 MA MAGPIE generator at Imperial College London. Direct experimental measurements of the diameter variation during the collapse and formation phase of the precursor column are presented, along with soft x-ray emission, and quantitative radiography. In addition, data from twisted cylindrical arrays are presented which give additional information on the behavior of coronal plasma generated in wire array z pinches. Three stages in precursor column formation are identifiable from the data: broad initial density profile, rapid contraction to small diameter, and slow expansion after formation. The correlation of emission to column diameter variation indicates the contraction phase is a nonlinear collapse resulting from the increasing on-axis density and radiative cooling rate. The variation in the minimum diameter is measured for several array materials, and data show good agreement with a pressure balance model. Comparison of column expansion rates to analytical models allows an estimate of column temperature variation, and estimates of the current in the column are also made. Formation data are in good agreement with both fluid and kinetic modeling, but highlight the need to include collisionless flow in the early time behavior.

Journal Article↗
PubMed2006

Bilateral medialization thyroplasty: an effective approach to severe, chronic aspiration.

AIMS: To demonstrate the efficacy of bilateral medialization thyroplasty as a treatment for severe, chronic aspiration. To review the literature on surgical options available in the treatment of severe aspiration. MATERIALS AND METHODS: Three cases that underwent bilateral medialization thyroplasty are described. The technique used was the standard medialization thyroplasty described by Isshiki as a unilateral procedure. The assessment and rehabilitation of these patients is discussed. RESULTS: All patients stopped aspirating following surgery. One patient returned to a normal diet and one patient returned to a solid diet. All patients required a permanent tracheostomy. CONCLUSION: Bilateral medialization thyroplasty offers an effective surgical option in the treatment of severe, chronic aspiration. It maintains good voice, with a possible return to oral diet. The operation is easily reversible if the patient's condition alters.

Aged↗
PubMed2005

Air bag injury as a cause of inflammatory myofibroblastic pseudotumour of the subglottic larynx progressing to myositis ossificans.

Inflammatory myofibroblastic pseudotumour (IMFPT) is a rare condition. The clinical presentation can be indistinguishable from that of a malignant neoplasm. The most frequently affected organ is the lung; a much less common site is the larynx and subglottic involvement is particularly rare. Trauma is purportedly one potential aetiological factor, although there have been no previous reports of IMFPT occurring in the larynx secondary to external laryngeal trauma. We present a case of IMFPT of the subglottis which occurred subsequent to external trauma of the neck sustained during air bag inflation in a road traffic accident. This mechanism has not been previously reported. Furthermore, the lesion progressed uniquely to show myositis ossificans-like maturation over time. The patient was ultimately treated by means of complete local excision.

Accidents, Traffic↗
PubMed2004

Pseudoaneurysm after total pharyngolaryngectomy with jejunal graft insertion: two different presentations.

Pharyngeal reconstruction after total pharyngolaryngectomy using a jejunal graft is now a common procedure in head and neck oncological surgery. The vascular supply of this graft comes from the anastomosis between a branch of the mesentric artery and a branch of the external carotid artery. We report two cases of pseudoaneurysm, one at the site of ligation of the lingual artery and the other at the site of arterial anastomosis. One presented with dramatic hematemesis and was managed by the interventional radiologist, and the second presented with a pulsating neck mass and required a surgical revision. In both cases, the jejunal graft survived.

Aged↗
PubMed2001

Biosynthesis and insecticidal properties of plant cyclotides: the cyclic knotted proteins from Oldenlandia affinis.

Several members of the Rubiaceae and Violaceae families produce a series of cyclotides or macrocyclic peptides of 29-31 amino acids with an embedded cystine knot. We aim to understand the mechanism of synthesis of cyclic peptides in plants and have isolated a cDNA clone that encodes the cyclotide kalata B1 as well as three other clones for related cyclotides from the African plant Oldenlandia affinis. The cDNA clones encode prepropeptides with a 20-aa signal sequence, an N-terminal prosequence of 46-68 amino acids and one, two, or three cyclotide domains separated by regions of about 25 aa. The corresponding cyclotides have been isolated from plant material, indicating that the cyclotide domains are excised and cyclized from all four predicted precursor proteins. The exact processing site is likely to lie on the N-terminal side of the strongly conserved GlyLeuPro or SerLeuPro sequence that flanks both sides of the cyclotide domain. Cyclotides have previously been assigned an antimicrobial function; here we describe a potent inhibitory effect on the growth and development of larvae from the Lepidopteran species Helicoverpa punctigera.

Amino Acid Sequence↗
PubMed2001

Effect of errors in the sequence of optical densities from the Roche AMPLICOR HIV-1 MONITOR assay on the validity of assay results.

Specifications for the AMPLICOR HIV-1 MONITOR kit indicate that the results are invalid if the optical densities (ODs) from the PCR-amplified sample that are between 0.1 and 2.3 units are out of sequence. However, among 11,904 assays, results were biased only when ODs of 0.2 to 2.0 units were out of sequence, reducing the rate of invalid results from 3.2 to 0.59%.

Diagnostic Errors↗
PubMed2000

Cloning, localisation and functional expression of the human orthologue of the TREK-1 potassium channel.

We have cloned human TREK-1, one of the newly emerging mammalian family of 2-P domain potassium channels. The channel has 411 amino acids with a 41-amino-acid extension at the C-terminus when compared with the cloned mouse TREK-1 channel. Expression of hTREK-1 produced a substantial hyperpolarising shift in resting membrane potential accompanied by the induction of large, outwardly rectifying, non-inactivating currents which were potassium selective. Pharmacologically, hTREK-1-mediated currents were only blocked to a limited extent by classic potassium channel blockers or open channel pore blockers known to potently inhibit other channels. The channel was reversibly potentiated by arachidonic acid. CNS distribution of hTREK-1 is widespread with higher levels being observed in caudate, putamen, amygdala, thalamus and spinal cord. Only low levels of expression were seen in the majority of peripheral regions. Thus, hTREK-1, although functionally and pharmacologically similar to mouse TREK-1, appears to have a more CNS-specific distribution.

Amino Acid Sequence↗
PubMed2000

The effect of topical adrenaline on the development of myringosclerosis after tympanostomy tube insertion.

OBJECTIVE: To determine the effect of topical adrenaline application after myringotomy and before tympanostomy tube placement on the development of myringosclerosis. STUDY DESIGN: A prospective, randomized, double-blind study, with each patient acting as his or her own control. Ethical approval and full parental consent were obtained. SETTING: Department of Otorhinolaryngology-Head and Neck Surgery in a university teaching hospital. PATIENTS: Fifty children satisfying inclusion and exclusion criteria for first-time tympanostomy tube insertion. THERAPEUTIC INTERVENTION: Myringotomy followed by adrenaline application to incision before tympanostomy tube insertion. Control contralateral ear received saline application after myringotomy. Follow-up examination was done 14 to 21 days after surgery and again after 1 year by a single blinded surgeon. MAIN OUTCOME MEASURE: Comparison of myringosclerosis between adrenaline-treated ears and matched control ears. RESULTS: No difference was found in early morbidity between the two groups of ears. Myringosclerosis after 1 year was not found to have been significantly affected by adrenaline application (p = 0.2) CONCLUSION: The use of adrenaline on the myringotomy site before tympanostomy tube placement was not found to influence early postoperative morbidity or the later development of myringosclerosis.

Administration, Topical↗
PubMed1999

CD8+ lymphocytes in pregnancy and HIV infection: characterization of CD8+ subpopulations and CD8+ noncytotoxic antiviral activity.

The distribution and function of lymphocytes vary in different clinical states. The object of this study was to characterize the CD8+ lymphocyte subpopulations and CD8+ anti-HIV suppressor activity in HIV-infected and uninfected pregnant and nonpregnant women. The total percentage of CD8+ lymphocytes was not altered by pregnancy but the percentage of activated CD8+ T cells increased during pregnancy and decreased postpartum. HIV infection in pregnant women resulted in both an increased percentage of CD8+ lymphocytes and a marked increase in activated and memory CD8+ lymphocyte subsets, which did not change in the postpartum period. Most HIV-infected women had CD8+-mediated noncytotoxic antiviral activity. However, the activity was not correlated with alterations in CD8+ lymphocyte subsets. This study provides baseline information on changes in CD8 immunologic parameters during pregnancy and HIV infection for further studies that employ antiretroviral therapeutic regimens capable of impacting the immune response.

Adult↗
PubMed1999

Population structure and dispersal of the saltmarsh mosquito Aedes vigilax in Queensland, Australia.

Population genetics of the mosquito Aedes vigilax (Skuse) (Diptera: Culicidae), a major vector of arboviruses (e.g. Barmah Forest, Ross River), were investigated to obtain an indirect estimate of mosquito dispersal characteristics in typical habitats of Aedes vigilax in south-east Queensland: on the off-shore islands of Moreton Bay and on the mainland where disjunct breeding populations of Ae. vigilax are distributed along intertidal marsh. Six allozyme loci were assessed for genetic differentiation between samples from 11 localities. Significant larval variation between some breeding sites was attributed to site-specific selection. Nonsignificant genetic differentiation was found among collections of adult mosquitoes caught in light traps throughout the study area (exceeding 60x27 km), indicating widespread dispersal. As distances of < or = 9 km over water did not appear to act as effective barriers to Ae. vigilax dispersal, localized control activities applied to Ae. vigilax breeding sites are unlikely to be effective against the vagile adult population. Therefore, the contiguous shires programme of broad acre control is endorsed to prevent the spread of arboviruses carried by Ae. vigilax

Aedes↗
PubMed1998

Adhesion reduction as a new treatment innovation.

A new treatment option, an antiadhesion device, has proved effective in the reduction of postoperative adhesion formation and is now approved for use in the United States. The device is a thin, filmy membrane composed of two organic substances that are resorbed by the body. The device is inserted intraoperatively between apposing tissue surfaces that are potentially adhesiogenic. It proved effective in reducing the incidence of adhesions after both abdominal and pelvic surgery.

Abdomen↗
PubMed1998

Detection of GB virus C by the RT-PCR LCx system.

The recent publication of representative genomic sequences of GBV-C has permitted the selection of PCR primers for detection of GBV-C in clinical samples by PCR techniques. Traditional amplification methodologies which couple reverse transcription polymerase chain reaction (RT-PCR) and Southern blot detection are slow, cumbersome, and can be technique dependent. This has hampered studies to determine the clinical significance of GBV-C. We report the selection of highly conserved PCR primers and a probe useful for semi-automated RT-PCR using the Abbott LCx system. This adaptation of the LCx system expands its capabilities to include the detection of RNA by RT-PCR, in addition to DNA detection by ligase chain reaction (LCR).

Automation↗
PubMed1998

Sublingual midazolam premedication in children: a dose response study.

The purpose of this study was to evaluate various doses of sublingual midazolam premedication in children. In our prospective, double-blind, placebo-controlled trial, children (n = 102, age range 12 to 129 months) scheduled for day surgery were randomized to receive either midazolam in one of three doses (0.25, 0.5, or 0.75 mg.kg-1) or placebo. Injectable midazolam was mixed with a thick grape syrup and placed under the tongue; the patient was asked to hold it as long as possible before swallowing. Children readily accepted the mixture. Analysing all patients randomized, none of the children receiving placebo vs 28% receiving 0.25 mg.kg-1 (P = 0.02), 52% receiving 0.5 mg.kg-1 (P < 0.001), and 64% receiving 0.75 mg.kg-1 (P < 0.001) of midazolam showed satisfactory sedation (drowsy) at 15 min after administration. Children receiving the two higher doses of midazolam (0.5 and 0.75 mg.kg-1) accepted mask induction willingly, while the group receiving 0.25 mg.kg-1 resembled the placebo group (P < 0.05).

Adjuvants, Anesthesia↗