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Biomedical subjects

K L Evans

Publications and source records attributed to K L Evans.

At least 37 records · Page 2Linked to original sources
PubMed1998

Recognition and management of sinusitis.

Acute sinusitis frequently follows upper respiratory tract infections. Patients complain of headache, facial pain, fever and purulent rhinorrhoea. Diagnosis is based upon the symptoms, and treatment comprises symptomatic relief with analgesics, topical or systemic decongestants and steam inhalation. If indicated, antibiotics should be given for an adequate period of time. Patients with chronic sinusitis complain of a combination of nasal obstruction, rhinorrhoea and postnasal drip associated with intermittent facial pain, with symptoms persisting for 3 months or more. Predisposition to the condition may be caused by rhinitis (allergic or nonallergic) and anatomical variants. Failure of mucociliary transport and sinus ostial obstruction leads to mucosal oedema, mucous hypersecretion and chronic infection. Current treatment aims are to control rhinitis and improve ventilation and function of the sinuses. Rhinitis may be controlled with the long term use of topical corticosteroids, mast cell stabilisers or antihistamines, either alone or in combination. Secretions may be cleared with steam inhalation and/or saline nasal douching. Failure to control chronic sinusitis with medical treatment may indicate surgery. The aim of surgery is to improve ventilation and facilitate drainage of the sinuses, allowing the restoration of normal function. Removal of nasal polyps, reduction of inferior turbinates or septal straightening may be all that is required. Some patients will need endoscopic ethmoidectomy and middle meatal antrostomy. Improved ventilation in the ethmoid infundibulum may help to resolve disease in maxillary and frontal sinuses. Medical treatment of underlying rhinitis will need to be continued postoperatively, often in the long term, while special consideration needs to be paid to sinusitis in children, in relation to dental disease and in the immunosuppressed. Complications of acute and chronic sinusitis include intraorbital and intracranial sepsis. These potentially lethal complications need urgent evaluation with high resolution computerised tomography (CT) scanning, intravenous administration of broad spectrum antibiotics (including anaerobic and microaerophilic cover) and urgent surgical drainage as appropriate.

AIDS-Related Opportunistic Infections↗
PubMed1997

Novel transcribed sequences neighbouring a translocation breakpoint associated with schizophrenia.

A 1.3Mb chromosome 11-specific yeast artificial chromosome (YAC) that spans a t(1;11) translocation breakpoint associated with major psychosis has been used to enrich cDNAs that are encoded within it and expressed in the human foetal brain. Database analysis of the selected fragments led to the identification of 54 clones matching alpha-tubulin, 4 fragments matching two anonymous human expressed sequence tags (ESTs) and 8 fragments giving no database matches. The clones matching alpha-tubulin led to the identification of a novel alpha-tubulin locus located approximately 250 kb proximal to the translocation breakpoint. Extensive sequence and expression analysis of this locus suggests that this is a processed pseudogene, although a long open reading frame is maintained and the possibility that an abnormally acting protein may be expressed in a highly tissue or developmental specific manner cannot be discounted. The novel cDNA fragments map up to 700 kb proximal to the translocation breakpoint and are associated with potential CpG islands. Reverse transcriptase polymerase chain reaction (RT-PCR) expression analysis and high resolution genomic mapping suggest that they may comprise up to three novel genes. No major disruption of the identified fragments could be detected in the genomic DNA of translocation carriers. The psychosis associated with this translocation may therefore be due to position effects on the transcription of these genes or an involvement of translocated chromosome 1 sequences.

Chromosomes, Artificial, Yeast↗
PubMed1995

A contiguous clone map over 3 Mb on the long arm of chromosome 11 across a balanced translocation associated with schizophrenia.

Forty-nine clones derived by microdissection of a schizophrenia-associated t(1;11)(q42.1;q14.3) breakpoint region have been assigned by somatic cell hybrid mapping to seven discrete intervals on the long arm of human chromosome 11. Eleven of the clones were shown to map to a small region immediately distal to the translocation breakpoint on 11q. A 3-Mb contiguous clone map of this region was established by isolation of corresponding YAC recombinants. The contig was oriented and shown to traverse the translocation breakpoint by FISH and microsatellite marker analysis. This contig will facilitate the isolation of candidate sequences whose expression may be affected by the translocation.

Base Sequence↗
PubMed1995

Management of posterior laryngeal and laryngotracheoesophageal clefts.

OBJECTIVE: To review the clinical features, associated congenital abnormalities, management, and morbidity of infants presenting with posterior laryngeal and laryngotracheal clefts. DESIGN: Case series. SETTING: Great Ormond Street Hospital for Sick Children NHS Trust, London, England. PATIENTS: Consecutive sample of 44 patients presenting with posterior laryngeal and laryngotracheal clefts between December 10, 1979, and January 30, 1992. MAIN OUTCOME MEASURES: Clinical features, incidence of surgery, and associated morbidity and mortality related to different types of airway cleft. RESULTS: The main presenting features were stridor and aspiration, which were more evident with the more extensive clefts. Twenty-five patients (56%) had associated congenital abnormalities. Fourteen patients (32%) were treated conservatively. Sixteen patients (36%) underwent primary endoscopic surgical repair. Eight patients (18%) underwent primary repair via an anterior laryngofissure; and six patients (14%) underwent primary repair via a lateral pharyngotomy. Eight patients (18%) required revision surgery, two (4%) of them on more than one occasion. Ten patients (23%) required fundoplication to control gastroesophageal reflux. Six patients (14%) died. CONCLUSIONS: The identification of an airway cleft requires a high index of suspicion. Morbidity and mortality are reduced by securing the airway, controlling gastroesophageal reflux, and using a multidisciplinary pediatric team. We recommend the anterior laryngofissure because of the ease of surgical access.

Abnormalities, Multiple↗
PubMed1995

Identifying genes within microdissected genomic DNA: isolation of brain expressed genes from a translocation region associated with inherited mental illness.

An improved protocol has been developed for physical enrichment of cDNA sequences by hybridization to genomic DNA. When applied to microdissection recombinants derived from a translocation breakpoint region associated with inherited mental illness, a single cycle of the procedure permitted enriched cDNAs to be visualized directly by agarose gel electrophoresis. Hybridization screening of a library of clones derived from the enriched cDNAs, employing the genomic resource as a probe, led to the identification of six novel gene fragments. This general approach to the isolation of regionally encoded genes could be applied to any subchromosomal interval as a first step towards global transcription map construction.

Animals↗
PubMed1995

Direct microdissection and microcloning of a translocation breakpoint region, t(1;11)(q42.2;q21), associated with schizophrenia.

We describe the generation of large-fragment microclone libraries from the chromosomal breakpoint of a reciprocal balanced translocation linked to schizophrenia. The abnormality was visible under the phase-contrast microscope, allowing direct dissection from unstained, unbanded metaphases. Two separate microdissection experiments yielded 443 and 672 recombinants, respectively. Following complete EcoRI digestion, inserts with an average size of 0.3 kb (range, 0.2-3 kb) were obtained in the first experiment and 1.5 kb (range, 0.15-6.5 kb) in the second. FISH analysis of pooled clones "painted" back onto the derivative chromosome and assignment of microclones to somatic cell hybrids confirmed the fidelity of the method. Microdissection of chromosome regions identified by karyotype rearrangements in unstained, unbanded metaphases is a potentially powerful tool for positional cloning.

Base Sequence↗
PubMed1995

Regional localisation of 19 brain expressed sequence tags to human chromosome 11 using PCR amplification of somatic cell hybrid DNAs.

Expressed sequence tags (ESTs) provide an efficient route to the identification of genes involved in normal development and in disease. PCR amplification of somatic cell hybrid DNAs was used to localise 22 brain-derived ESTs to subregions of human chromosome 11. Problems encountered with the standardised PCR conditions were overcome by optimising the annealing temperatures and the use of "touchdown" PCR. Amplification of the correct target sequence allowed the mapping of 19 ESTs, 8 to the short arm and 11 to the long arm of chromosome 11. No definitive localisation could be determined for the three remaining ESTs.

Animals↗
PubMed1995

Placement and refined mapping of established and new markers on human chromosome 11q using a small panel of somatic cell hybrids.

Constructing detailed chromosome maps relies on the ability to place new markers rapidly and accurately. Here we map two new anonymous DNA markers precisely on chromosome 11q and refine the location of established markers using a panel of just six fragmentation hybrids, with reference to four translocation chromosomes. As several of the hybrids retain multiple segments of chromosome 11, it is possible to quickly assign new markers to subintervals using this modest set of hybrid DNAs.

Base Sequence↗
PubMed1994

High-frequency jet ventilation--a review of its role in laryngology.

High-frequency jet ventilation (HFJV) is a safe, effective anaesthetic technique with a low risk of aspiration which has not yet gained wide acceptance in laryngology. Following anaesthesia and muscular relaxation the patient is intubated with a size 7FG infant feeding catheter and ventilation is achieved by delivering small bursts of anaesthetic gas at high frequency. The mechanisms of gas exchange are thought to be little different from those of conventional ventilation. We have found HFJV to be of value in laryngoscopy, laryngo-tracheal reconstruction, tracheoplasty, bronchoscopy and tonsillectomy. The advantages include: (a) ease of intubation, especially in the presence of a supraglottic mass; (b) improved surgical access compared with a conventional endotracheal tube; and (c) protection of the airway by the inherent 'auto-PEEP' effect. Care must be taken to ensure that conditions allow adequate exhaust of expired gas. Humidification of inspired gas is essential during prolonged procedures.

Anesthesia↗
PubMed1993

Postoperative evaluation of renal function after surgical correction of a ureterovaginal fistula in a cat.

Unilateral hydronephrosis and urinary incontinence, secondary to a ureterovaginal fistula, were corrected in a cat after surgical excision of the fistula and implantation of the affected ureter into the bladder. Salvage of the kidney was attempted because underlying chronic bilateral renal disease was suspected. Renal scintigraphy was used to monitor improvement in the function of the previously obstructed kidney after surgery.

Animals↗
PubMed1993

Human olfactory marker protein maps close to tyrosinase and is a candidate gene for Usher syndrome type I.

Olfactory marker protein (OMP) shows olfactory neuron-specific expression in rodents. We recently reported tight linkage on mouse chromosome 7 of OMP to the shaker-1 deafness mutant, between the tyrosinase and globin loci. Here we isolate and map the human homologue. Our results show that OMP maps immediately centromeric to tyrosinase on the long arm of human chromosome 11. Genetic linkage to this region has recently been established for Usher Syndrome Type I, an autosomal recessive blindness and deafness disorder and a putative homologue of the shaker-1 mutant. OMP is thus a candidate gene for both congenital deafness defects.

Animals↗
PubMed1992

Intranasal splints and their effects on intranasal adhesions and septal stability.

Intranasal splints have been used to maintain septal stability and prevent intranasal adhesions following septal surgery. However, their efficacy and attendant morbidity have received surprisingly little attention. Our prospective study of 100 adults was divided into patients undergoing septoplasty or submucous resection of the nasal septum alone (n = 50) and those undergoing combined septal and inferior turbinate surgery (n = 50). All patients were randomized to have paired silicon rubber splints inserted for 7 days or not at all. All noses were additionally packed with 2 pieces of Jelonet for 12-20 h and examined and cleaned at 1 and 6 weeks post-operatively. The position of the septum, patency of the airways, presence of adhesions and degree of discomfort were recorded. Statistical analysis of the 89 complete sets of results obtained indicated splints added significantly to post-operative discomfort in both groups, with no demonstrable benefit to the patient.

Adolescent↗
PubMed1992

A randomized comparison of three post-tonsillectomy diets.

Traditionally, soft cold foods have been recommended after tonsillectomy to aid comfort and haemostasis but, more recently, rougher foods have been advocated to promote physiologically normal deglutition. This trial was designed to discover whether post-tonsillectomy dietary advice has any influence on recovery. 150 patients due to undergo tonsillectomy were prospectively randomized to 1 of 3 diets: mainly rough food, mainly soft food, and no advice except to eat regularly. Food consumption, analgesia intake and pain levels were recorded daily by each patient. Tonsillar fossa slough and secondary haemorrhage were evaluated 1 and 2 weeks after surgery. Results of 137 patients were obtained. There were no significant differences between the diets regarding post-operative pain, analgesic required, healing rates or secondary haemorrhage. Specific post-tonsillectomy dietary advice need not be given, other than to encourage regular eating.

Adolescent↗
PubMed1991

Salivary function of persons with hereditary epidermolysis bullosa.

Oral alterations of the hard and/or soft tissues are commonly associated with the different types of epidermolysis bullosa (EB). The relationship of oral soft and hard tissue changes to the disease mechanisms in different EB types remains to be elucidated. The purpose of this investigation was to evaluate selected aspects of salivary function in a healthy control population and in persons affected with different types of EB. Sixty-one patients with EB, representing all the major types of EB, and 36 unaffected persons were examined to measure their stimulated salivary flow rates and salivary levels of IgA, albumin, and total protein. Our results show that none of the types of EB demonstrated a decreased salivary flow rate. However, patients with recessive dystrophic EB had significantly elevated salivary IgA, albumin, and total protein levels. The increased IgA level seen in this form of EB appears most likely to be related to the high prevalence of oral blistering rather than the result of altered mucosal immune function. Despite severe cutaneous and extracutaneous involvement associated with inherited EB, we found no evidence to support the hypothesis of abnormal salivary function or mucosal immunity in this disease. Taken together, these findings suggest that the rampant dental caries seen in the severe forms of EB are likely attributable to nonsalivary factors such as enamel involvement, soft tissue alterations, and/or diet. Alternatively, there may be mucosal immunity or salivary enzyme alterations that influence oral disease in these patients, but these were not evaluated in this investigation.

Adolescent↗