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Biomedical subjects

G Walters

Publications and source records attributed to G Walters.

At least 19 recordsLinked to original sources
PubMed2005

Scanning laser tomography of full thickness idiopathic macular holes.

AIM: We used a retinal tomographic analyser to study the profile of the retinal surface in patients with stage 3 and 4 idiopathic macular holes, to attempt to elucidate the direction of forces present. METHODS: The Heidelberg retina tomograph was used to acquire a three-dimensional tomographic image of the macula in each eye of 21 consecutive patients with full thickness macular hole. RESULTS: The surface profile showed an elevated rim around the 24 macular holes imaged, with a gently sloping outside edge and a steeply sloping inside edge. In addition, a ring of elevated tissue around the edge of the hole was observed in all the holes and also in two of the fellow 'normal' eyes. This ring of elevated tissue was presumed to represent a ring of persistent vitreo-retinal traction around the fovea in the presence of a perifoveal posterior vitreous detachment. This is consistent with antero-posterior traction persisting in stage 3 and 4 full thickness macular holes. The mean ring diameter was 480 mum, when present in the fellow eye but was 950 microm in the presence of a macular hole, which we argue is suggestive of centrifugal displacement of retinal tissue on the formation of a stage 3 macular hole and provides evidence for tangential traction. CONCLUSION: We suggest that antero-posterior traction forces are the primary cause of full thickness macular holes, with these forces persisting in stage 3 and 4 macular holes, while tangential forces serve to enlarge the hole at this later stage.

Aged↗
PubMed2001

Glomerular T cells in Heymann nephritis.

Active Heymann nephritis (HN) is a rat model of human membranous nephropathy. The appearance of T cells within the glomeruli of HN rats suggests a role for these cells in the pathogenesis of the disease. The aims of this study were to investigate T cells infiltrating the glomerulus in HN in Lewis rats by polymerase chain reaction (PCR) of their Vbeta chains, CDR3 spectratyping and sequencing. HN was induced in Lewis rats by immunization with renal tubular antigen (Fx1A) in CFA. Kidneys were collected between 4 and 10 weeks. The glomeruli were separated, homogenized and RNA extracted. RT-PCR, CDR3 spectratyping and sequencing were used to further characterize the infiltrating T cells. Multiple Vbeta families showed restriction of their CDR3 spectratypes in each animal. Several TCR Vbeta families had identical-sized restricted spectratypes across several different animals. Four Vbeta families were sequenced. In three of those four families, the dominant clones showed identical sized CDR3 regions and a striking over-expression of Jbeta2.6. Further analysis of the CDR3 regions of the Jbeta2.6 clones showed a significant restriction of the amino acids at four of the six CDR3 positions. Glomerular T cells bearing similar CDR3 sequences, using Jbeta2.6 and expressing at least two, and possibly more, Vbeta genes are involved in the pathogenesis of HN.

Amino Acid Sequence↗
PubMed2001

The use of subtenon ropivacaine in managing strabismus with adjustable sutures.

BACKGROUND: Squint angle alterations with the use of adjustable sutures after strabismus surgery can be painful. Ropivacaine is a long-acting local anesthetic that, at low doses, produces sensory block with limited nonprogressive motor block. METHOD: We performed a double-blind, randomized, pilot study using subtenon ropivacaine or placebo at the time of surgery in patients undergoing adjustable suture surgery. Surgery was performed by the same surgeon in each case. Later in the day, the same surgeon adjusted the sutures. At the time of adjustment, the patient recorded pain using a linear pain score, and the surgeon recorded ease of adjustment using a linear score. The results of surgery were noted at 4 weeks. RESULTS: Ten patients were randomized to receive ropivacaine and 11 to receive placebo. All 10 of the ropivacaine group and 9 of the placebo group had suture adjustment. In the ropivacaine group, there was a significantly lower pain score (P <.05, Mann-Whitney U test) but no significant difference in ease of adjustment. There appeared to be no demonstrable difference in the results of surgery between the 2 groups. CONCLUSION: Ropivacaine appears to reduce the pain of postoperative suture adjustment without adversely affecting the final outcome, although it does not appear to ease the adjustment itself. This small pilot study shows promising results in postoperative analgesia in these patients, although further larger trials are recommended.

Adult↗
PubMed2001

Viral causes of the acute retinal necrosis syndrome.

Acute retinal necrosis has been described as a clinical entity for nearly 30 years. Acute retinal necrosis is a potentially visually devastating necrotizing vaso-occlusive retinitis affecting both healthy and immunocompromised patients. Acute retinal necrosis is caused by the herpes group of viruses, mainly varicella zoster, herpes simplex types 1 and 2, and, rarely, cytomegalovirus. Recently, polymerase chain reaction techniques have enabled detection of very small amounts of viral DNA from intra-ocular fluid samples. This can help in both the diagnosis of atypical cases of retinitis and uveitis and directing treatment in cases of acute retinal necrosis.

Antiviral Agents↗
PubMed2000

Confrontation naming after anterior temporal lobectomy is related to age of acquisition of the object names.

Decline in visual confrontation naming ability may occur as a postacute complication of left anterior temporal lobectomy (ATL) for the treatment of intractable mesial temporal lobe epilepsy. In this study of 26 left ATL patients who demonstrated postsurgery decline on a standardized naming measure, it was hypothesized that naming performance would be significantly associated with specific attributes of the object names. We investigated the relation between performance on the Boston Naming Test (BNT) and the following attributes of the test items: living versus nonliving category (L/NL), word length (WL), written word frequency (WF), and age of acquisition (AoA). Regression analyses revealed that AoA and WF were significant predictors of preoperative group performance. AoA was the only significant predictor of performance after left ATL. For the 17 individuals who demonstrated a statistically meaningful decline on the BNT, as indicated by a Reliable Change Index, individual logistic regressions demonstrated that AoA was the strongest and most consistent predictor of postoperative success/failure for items that had been named correctly preoperatively. Consistent with the literature on naming errors in elderly normals and patients with aphasia or semantic dementia, the results provide evidence that object names learned in late childhood are among the most vulnerable when there is a decline in object naming ability. Investigation of additional attributes and semantic knowledge for the concepts represented by the pictured objects will be necessary to determine whether the naming deficit associated with TLE and ATL reflects an impairment of phonological word-form retrieval, semantics, or both.

Adult↗
PubMed1999

Sight-threatening acute orbital swelling from peribulbar local anesthesia.

Severe allergic reactions to peribulbar local anesthesia are extremely rare. A 70-year-old woman presented with acute orbital swelling and optic nerve dysfunction after a peribulbar local anesthetic injection. The patient was treated with acute orbital decompression as well as intravenous antibiotics and methylprednisolone; she made a good recovery. An allergy, probably to lignocaine, was the most likely cause. Urgent recognition and treatment of this condition may prevent potentially serious visual consequences.

Acute Disease↗
PubMed1999

Continuation and maintenance pharmacotherapy in geriatric depression: an open-trial comparison of paroxetine and nortriptyline in patients older than 70 years.

We present preliminary data on the efficacy of paroxetine, as compared with nortriptyline, in preventing or delaying relapse and recurrence of major depression in elderly patients. Following double-blind, acute-phase pharmacotherapy, 25 patients (mean age = 72.5 years) began open-trial continuation treatment with paroxetine (mean dose = 24.5 mg/day), and 15 patients (mean age = 77.5 years) received nortriptyline (mean dose = 51.3 mg/day; mean blood level = 85.5 ng/mL). Over an 18-month period, paroxetine and nortriptyline have shown comparable efficacy in preventing or delaying relapse and recurrence, with 80% to 90% of patients remaining well. These data suggest that paroxetine holds promise for long-term maintenance treatment in patients in their 70s and older with depression; however, further controlled evaluation is necessary.

Age Factors↗
PubMed1997

The value of pre-operative investigations in local anaesthetic ophthalmic surgery.

This study was performed to assess the value of routine investigations performed on ophthalmic patients undergoing local anaesthetic surgery. Patients attending the pre-operative assessment had investigations ordered as outlined in accordance with the guidelines of the Joint Working Party on Anaesthesia in Ophthalmic Surgery. The results of investigations were sealed in a clearly marked envelope and stapled to a prominent position on the notes. Any envelopes found unopened at the end of surgery were assumed to have been unseen by either the anaesthetist or surgeon. The effects on patient management were noted. Abnormal results were found in 102 of 314 investigations performed in 100 patients. Of the 100 envelopes 95 were unopened at the end of surgery. No patients had their peri-operative management changed because of the investigations performed. An adequate pre-operative assessment with a history and examination is sufficient in most patients undergoing local anaesthetic ophthalmic surgery, avoiding unnecessary investigations.

Aged↗
PubMed1997

Efficacy of a central venous access service.

A central venous access service (CVAS) was created in a 600-bed teaching hospital to do elective percutaneous central venous catheterization (PCVC) in a safe and expeditious manner. A vascular surgeon, physician assistants, and registered nurses specializing in intravenous therapy comprise the service. From November 1990 through June 1995, the CVAS was consulted for 1,008 PCVC procedures--853 primary insertion attempts and 155 guidewire exchanges. Various types of catheters were inserted for hemodialysis, fluid and medication administration, chemotherapy, and total parenteral nutrition. The primary insertion failure rate was 4% (31/853) and the major complication rate was 1% (8/853); major complications consisted of four pneumothoraces and four lymphocutaneous fistulae. Success and complication rates were superior to those previously reported for less experienced operators. The favorable results of this study support the efficacy of a CVAS.

Adolescent↗
PubMed1997

Malignant hypertension presenting as blurred vision in a 43 year old intravenous drug abuser.

A 43 year old intravenous drug abuser presented to the accident and emergency department with a three week history of bilateral visual loss and frontal headaches. Fundoscopy revealed bilateral retinal cotton wool spots and haemorrhages and an ophthalmic opinion was requested. His blood pressure was subsequently found to be 210/140. A diagnosis of malignant hypertension was made and blood pressure was gradually controlled on oral antihypertensives. This case illustrates the importance of checking the blood pressure of all patients presenting with visual loss.

Adult↗
PubMed1995

A software toolkit for hierarchical task analysis.

This paper describes a prototype software tool that offers support to the human factors specialist using hierarchical task analysis (HTA). The tool provides a direct manipulation diagram editor for HTA and provides high-quality output of analyses, in both graphic and automatically generated tabular form. The tool is implemented in Smalltalk-80 and currently runs on Macintosh computers.

Journal Article↗
PubMed1994

Training St John Ambulance volunteers to use an automated external defibrillator.

The key to improving survival from pre-hospital cardiac arrest lies in reducing the time interval between onset of cardiac arrest and defibrillation. Placing automated external defibrillators at strategic points in the community could potentially reduce this time interval, but would necessitate widespread training in defibrillation for lay people in addition to health care workers. There are unanswered questions regarding the ability of lay people to acquire and retain this skill when the training programme is, by necessity, very brief, (otherwise it would not be possible to train large enough numbers of people) and the skill is used infrequently. In this study, nurse and lay volunteer first-aiders were taught to use an automated external defibrillator, either by a 2-h, or a 4-h course, and their skills were assessed at training, and at 3 and 6 months afterwards. Using stringent assessment criteria, 54% of volunteers passed the assessment at every session. Little difference in acquisition or retention of skills between the nurse and lay volunteers, and the 2- and 4-h course groups was found. It is concluded that brief training in defibrillation for volunteer first-aiders is feasible.

Ambulances↗
PubMed1993

Nurse managers' perceptions of contracting for education, Part 1: Contracting and pre-registration education.

The introduction of the 'purchaser/provider' split into nurse education alters the relationship between service units (or the education purchasers) and colleges of health studies (the education providers). The aim of this study was to identify how education purchasers view the new contracting arrangements, with regard to the provision of pre-registration and post-registration nurse education. In the first of two papers, findings are reported in relation to purchasers' views of pre-registration education. 24 people from one region, comprising senior nurses, and some non-nurse executives involved in the Working Paper 10 initiative, were interviewed. The findings indicate that most of the respondents want a close working relationship with an education provider. They hope that this relationship will be responsive to, and understanding of the needs of the service, and that it will be enhanced by the contracting process. The majority see the need to formally monitor the quality of the output of the college, to ensure that their educational needs are being met by their provider, but they are unsure as to how this can be done. Finally, although it is understood that if service units become dissatisfied with their local college, they can contract with alternative colleges for pre-registration education, the majority of these respondents believe that this will not be desirable or feasible.

Attitude of Health Personnel↗