Biomedical subjects
G Sutton
Publications and source records attributed to G Sutton.
Excimer retreatment for scarring and regression after photorefractive keratectomy for myopia.
AIMS/BACKGROUND: Scarring associated with regression of refractive effect can occur after photorefractive keratectomy (PRK) for myopia. The experience of treating these complications is reported. METHODS: Eighteen of 285 eyes (6.3%) were retreated with the excimer laser. Age, sex, preoperative primary treatment keratometry, pre-primary treatment, pre-retreatment and post-retreatment spherical equivalents, best corrected and uncorrected visual acuities were recorded and analysed. RESULTS: At 6 months post-retreatment, the mean spherical equivalent was -2.07 dioptres (D) (SD 4.60 D). This spherical equivalent persisted in eyes followed for 12 months (-2.85D, SD 4.09 D). Nine of 18 eyes (50%) had uncorrected visual acuity of 6/12 (20/40) or better. If retreatment was undertaken within 6.5 months of the initial PRK, then scarring was likely to recur (p = 0.035). Nine of 10 eyes (90%) which had a retreatment spherical equivalent less than two thirds of their primary treatment spherical equivalent were within plus or minus 1.25D from emmetropia after retreatment. Four of 11 eyes (36%) followed for 12 months after retreatment rescarred with further regression. CONCLUSION: The data showed that eyes with scarring and regression of myopia should not be treated with PRK within 6 months of the initial procedure. Eyes with the highest percentage of regression towards their initial myopia tend to have a poor response to retreatment.
Crystallization and preliminary X-ray investigation of recombinant simian immunodeficiency virus matrix protein.
Simian immunodeficiency virus matrix protein has been crystallized from Tris-HCl buffer with polyethylene glycol and isopropanol as precipitants. The crystals belong to space group C2 with unit cell dimensions a = 69.9 A, b = 115.2 A, c = 32.5 A, beta = 108.1 degrees and diffract X rays to a minimum Bragg spacing of 2 A. These crystals appear suitable for a high resolution structure analysis.
Comparison of the effect of heparin and aspirin versus aspirin alone on transient myocardial ischemia and in-hospital prognosis in patients with unstable angina.
OBJECTIVES: This study compared the effects of heparin and aspirin versus aspirin alone on transient myocardial ischemia and in-hospital prognosis in patients with unstable angina. BACKGROUND: Transient myocardial ischemia occurring in patients with unstable angina is associated with an adverse prognosis. Heparin and aspirin are two drugs used frequently in the treatment of this condition, but the effect of combination therapy versus aspirin alone on transient myocardial ischemia is unknown. METHODS: Two hundred eighty-five consecutive patients with unstable angina were randomized to receive either intravenous heparin plus oral aspirin (150 mg once daily) (Group H + A) or aspirin alone (Group A). Patients also received a beta-adrenergic blocking agent, diltiazem and intravenous nitrates. ST segment monitoring was performed for the 1st 48 h of treatment. Patients were followed up for the duration of their in-hospital stay. RESULTS: One hundred fifty-four patients (30 women, mean [+/- SEM] age 58.3 +/- 0.8 years) received heparin and aspirin (Group H + A), and 131 patients (26 women, mean age 60.6 +/- 0.8 years) received aspirin only (Group A). ST segment monitoring (11,622 h) yielded 244 episodes of transient myocardial ischemia of a total duration of 7,819 min. There were no significant differences between the two treatment arms in the number of patients with transient myocardial ischemia (27 [18%] in Group H + A vs. 31 [24%] in Group A), number of episodes (96 in Group H + A vs. 148 in Group A) or total duration of transient myocardial ischemia (2,911 min in Group H + A vs. 4,908 min in Group A). The incidence of in-hospital myocardial infarction or death was significantly higher in patients with transient myocardial ischemia (53% vs. 22%, p < 0.0001). Five of the six deaths occurred in patients with transient myocardial ischemia. Event-free survival from myocardial infarction or death was similar in both treatment groups. Preadmission therapy with aspirin was associated with a lower in-hospital infarction rate (19% vs. 34%, p = 0.01). CONCLUSIONS: The presence of transient myocardial ischemia in patients with unstable angina is associated with a significantly higher incidence of myocardial infarction or death in hospital. Combined therapy with heparin and aspirin compared with aspirin alone makes no difference in the development of these events, nor does it reduce the development of transient myocardial ischemia.
Duplex controlled angioplasty.
Duplex examination was carried out to assess lesions in peripheral arteries amenable to angioplasty. With the help of a special catheter, angioplasty of these lesions was performed under Duplex control. Sixteen patients presenting with claudication were examined by Duplex and 38 lesions were identified (31 stenoses, seven occlusions) and all the findings except one (vessel E1) were confirmed by subsequent angiography. Sixteen lesions were considered amenable to angioplasty and 13 lesions (in 10 patients) were selected for Duplex controlled angioplasty. A new catheter system which has a piezo-electric transducer at the centre of the balloon and integrated to a Duplex scanner via a catheter system interface, was used for the procedure. This allows the exact position of the balloon to be represented on the screen. Thirteen lesions (seven superficial femoral artery (SFA), three external iliac, two common iliac and one graft) were subjected to angioplasty under Duplex control. In one patient, the SFA was punctured directly under ultrasound control as the profunda was diseased. The guide wire was visualised in all cases and in the majority of cases, balloon size for the angioplasty was chosen by measurement of the arterial diameter by Duplex, which was also used for haemodynamic evaluation before, during and after the procedure. Eleven lesions (85%) underwent angioplasty entirely under Duplex control and additional X-ray control was needed in only two cases. In conclusion, Duplex allows the monitoring of both anatomical and haemodynamic parameters during angioplasty. It also reduces the risk of ionising radiation. Our initial experience has been encouraging as angioplasty was performed in the majority of lesions purely under Duplex control.
The effect of acidosis on the labelling of urinary ammonia during infusion of [amide-15N]glutamine in human subjects.
In three experiments [amide-15N]glutamine was infused intravenously in male volunteers. After 4-8 h of infusion acidosis was achieved by an oral dose of CaCl2 (1 mmol/kg). In one subject acidosis was maintained for 5 d. The acid load produced an approximately 3-fold increase in urinary NH3 excretion, with a small (approximately 20%) and transient increase in the isotope abundance of urinary NH3. Estimates of glutamine production rate (flux) were obtained in two experiments. There was no evidence that it was increased in acidosis. The extra NH3 production by the kidney represented only a very small part, about 3%, of the total glutamine production rate.
Chemotherapy of epithelial ovarian cancer: an overview.
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Refractive keratoplasty for post-graft astigmatism.
Refractive keratoplasty using modified relaxing incisions with compression sutures was performed on 33 patients with high post-keratoplasty astigmatism. The mean reduction in keratometric astigmatism was 8.38 dioptres from a preoperative mean of 12.21 dioptres (SD, 3.59) to 3.93 dioptres (SD, 2.13). All patients noted a marked functional improvement. Two patients required reoperation. One patient required resuturing. Our modification of undercutting the relaxing incisions greatly increases the range of astigmatism that can be treated with this technique.
A quality control algorithm for DNA sequencing projects.
Heterologous DNA sequences from rearrangements with the genomes of host cells, genomic fragments from hybrid cells, or impure tissue sources can threaten the purity of libraries that are derived from RNA or DNA. Hybridization methods can only detect contaminants from known or suspected heterologous sources, and whole library screening is technically very difficult. Detection of contaminating heterologous clones by sequence alignment is only possible when related sequences are present in a known database. We have developed a statistical test to identify heterologous sequences that is based on the differences in hexamer composition of DNA from different organisms. This test does not require that sequences similar to potential heterologous contaminants are present in the database, and can in principle detect contamination by previously unknown organisms. We have applied this test to the major public expressed sequence tag (EST) data sets to evaluate its utility as a quality control measure and a peer evaluation tool. There is detectable heterogeneity in most human and C.elegans EST data sets but it is not apparently associated with cross-species contamination. However, there is direct evidence for both yeast and bacterial sequence contamination in some public database sequences annotated as human. Results obtained with the hexamer test have been confirmed with similarity searches using sequences from the relevant data sets.
Imipenem prophylaxis in elective colorectal surgery.
In a randomized controlled study of 411 patients undergoing elective colorectal surgery, the efficacy and safety of two different regimens of imipenem were compared with those of a control regimen of cefuroxime plus metronidazole. Surgical infections occurred in 92 (26.4 per cent) of 349 evaluable patients. There were no major differences between the three treatment groups. It is concluded that imipenem is as effective as cefuroxime plus metronidazole in the prevention of sepsis after elective colorectal procedures.
Ifosfamide and mesna in epithelial ovarian carcinoma.
Ifosfamide is a cyclophosphamide analogue synthesized in the 1960s with antineoplastic activity demonstrated in early broad-ranging phase I studies conducted in Germany in the 1970s. Because of significant urothelial toxicity, phase II studies in ovarian cancer in this country were delayed until the urinary epithelial protector mesna became available in 1985. Since that time, two well-executed prospective trials have shown that this agent produces measurable responses in about 20% of women with ovarian epithelial cancer recurring after primary chemotherapy and in 12% of those with tumors refractory to first-line therapy with regimens including cisplatin. Toxicity includes moderate to severe hematologic toxicity, renal dysfunction which is usually reversible, and CNS abnormalities including lethargy, somnolence, and disorientation. The risk of toxicity may be increased in patients with compromised hepatic or renal function and in those with hydronephrosis or hypoalbuminemia.
Entry to the burns team: stressors, supports and coping strategies.
Employment as a member of a multidisciplinary burns team presents the individual with an enticing professional and personal challenge. Patients sustaining major burns require intense physical and psychological rehabilitation over an extended period of time, often drawing upon the services of a sole therapist. Although more attention is being paid to professional issues of 'burn-out' and general care of the health professional, there has been little published with regard to actual stressors experienced by burn staff. An understanding of stressors faced, and current support systems utilized, by an occupational therapist in the first 12 months in a major burns unit, illustrates the unique demands placed upon junior staff. Following this review possible coping strategies for the individual and institution at large are discussed. It is suggested that continuing education, supervision by senior staff and better staff/patient ratios, may facilitate an easier transition into the burns team and render staff better able to cope with continuing stressors.
Flow cytometric analysis of DNA content and RAS P21 oncoprotein expression in ovarian neoplasms.
Flow cytometric analysis of DNA content and ras p21 expression were studied in paraffin-embedded normal ovary (NO, n = 10), serous cystadenoma (SA, n = 11), serous tumors of low malignant potential (LMP, n = 13), and papillary serous cystadenocarcinoma (SCa, n = 7). Tissue for DNA analysis was processed via a modified Hedley technique; a separate aliquot of the same sample was stained with a monoclonal antibody directed to oncoprotein ras p21 (clone Y13259). NO (10/10) and SA (11/11) demonstrated diploid DNA stemlines; 4/12 LMP and 5/7 SCa were aneuploid. S-phase fraction varied with significant differences (p less than 0.001) for SA (mean = 4.4%), LMP (mean = 9.0%), and SCa (mean = 12.7%). When all cases were evaluated, p21 expression was relatively lower in NO and SA (mean = 4.2%) in contrast to LMP and SCa (mean = 13.0% and 8.1%). Diploid cases were examined separately, and lesions with high p21 expression were associated with a diagnosis of LMP/SCa (p less than 0.001), whereas diploid tissues with low p21 expression were associated with a nonmalignant diagnosis (NO/SA). This study suggests that aneuploidy or diploidy with high p21 expression (greater than 10%) may be associated with LMP or frankly malignant ovarian tumors.
Value of ambulatory ST segment monitoring in patients with chronic stable angina: does measurement of the "total ischaemic burden" assist with management?
OBJECTIVE: To assess the prognostic significance of transient ischaemic episodes during daily activities in patients with stable angina. PATIENTS AND METHODS: 172 patients with stable angina attending the cardiac outpatients departments of Hillingdon Hospital (n = 155) and the National Heart Hospital (n = 17) were prospectively studied by exercise testing and 48 hours of ambulatory ST segment monitoring, and followed for prognostic purposes for up to 39 months (mean 24.5 months). Patient inclusion depended on a clinical diagnosis of stable coronary artery disease which necessitated outpatient review (and antianginal treatment in 94% of patients). It was not dependent on objective evidence of reversible ischaemia. Events recorded during the follow up period included death, non-fatal myocardial infarction, unstable angina, and the requirement for revascularisation. RESULTS: 72 patients (42%) had transient ischaemic episodes during daily activities, and 104 patients (60.5%) had an ischaemic response to exercise. 63 patients (36%) had evidence of ischaemia on both investigations; with 59 (34%) having no documented ischaemia on either investigation. There were 27 patient events (15.7%) recorded over a mean 24.5 month follow up, including five deaths (2.9%) (three cardiac related (1.7%)), six non-fatal myocardial infarctions (3.5%), six admissions with unstable angina (3.5%), and 10 revascularisation procedures (5.8%). Of the nine "hard" or objective end points (cardiac death and non-fatal myocardial infarction), only two had evidence of transient ischaemia on ambulatory ST segment monitoring at initial investigation, with 10 of the 25 patients (38.5%) with any cardiac event having such episodes. CONCLUSIONS: The outcome in patients with chronic stable angina receiving standard medical treatment was good over a mean two year follow up period. For the purpose of assessing prognosis over this time scale, there was no advantage to performing ambulatory ST segment monitoring in such patients.
Abdominal wound closure using a running, looped monofilament polybutester suture: comparison to Smead-Jones closure in historic controls.
OBJECTIVE: To determine whether abdominal wound closure with a running, looped monofilament polybutester suture was as effective, inexpensive, and rapid as Smead-Jones closure using the same material. METHODS: Between April 19, 1990 and August 29, 1991, 154 patients undergoing major gynecologic surgery had wound closure using a running, looped monofilament polybutester suture. Controls were 154 patients undergoing similar surgical procedures in the 15 months immediately preceding the study period (January 5, 1989 to April 18, 1990) whose wounds were closed with 0 polybutester using the Smead-Jones technique. All patients received prophylactic cephalosporin antibiotic therapy and external pneumatic leg compression perioperatively. The subcutaneous tissues were not sutured after fascial closure, and the skin was closed with stainless-steel staples. There was no difference between the groups when compared by mean weight, mean ponderal index, number of previous abdominal operations, operative blood loss, or the use of chemotherapy or radiotherapy in the pre- or postoperative period. Both groups had similar rates of complicating medical conditions including insulin-dependent and non-insulin-dependent diabetes mellitus, hypertension, obstructive pulmonary disease, atherosclerotic coronary disease, or peripheral vascular disease. RESULTS: The use of a running closure with looped monofilament polybutester suture in the study patients resulted in a reduction in operating time when compared with controls. The rates of superficial separation and wound infection were similar in both groups. In the study group, there was one minor fascial separation and one wound dehiscence, which occurred when the running suture was inadvertently snipped during debridement of a superficial infection. CONCLUSION: Running closure with looped polybutester is an acceptable, inexpensive, and expeditious method of abdominal wound closure.
Double-blind randomised placebo-controlled dose-efficacy study of sustained release verapamil in chronic stable angina.
The efficacy and tolerability of sustained release verapamil (Securon SR) was investigated in twenty-four patients with chronic stable angina. Patients entered four randomised, double-blind treatment periods, each lasting one week of verapamil-SR 240 mg once daily, 360 mg once daily, 240 mg twice daily, and matching placebo. Four patients were withdrawn, but in one instance this was attributable to side effects from verapamil. Among the remaining twenty patients, mean frequency of angina fell from 4.25 episodes during the last five days of placebo to 2.35, 2.6 and 1.3 episodes during respective active treatments (all P less than 0.001). Compared with placebo the median percentage increase in time to 1 mV ST depression during treadmill exercise (12 hours post dose) was significant only with the regimen of verapamil-SR 240 mg given twice daily at +11% (P = 0.04). Total duration of exercise was also significantly longer and maximum ST depression significantly less only with the twice daily treatment (704 + 186 sec vs 648 + 203 sec; P = 0.03, and 1.75 + 0.73 mm vs 2.15 +/- 0.62 mm; P = 0.02). Side effects, predominantly constipation, breathlessness, and swollen ankles, occurred most frequently with verapamil-SR 360 mg. Thus, sustained release verapamil is well tolerated and effective in the treatment of angina. A regimen of 240 mg given twice daily emerges as superior to once daily treatments for 24-hour prophylaxis of angina.
Clean intermittent self-catheterisation for quadriplegic patients--a five year follow-up.
We present the findings of clean intermittent self-catheterisation (CISC) as a long term method of bladder management for 36 quadriplegic spinal cord injured patients, primarily at C6/C7 level, who were taught CISC between 1983 and 1987. Success in CISC was assessed by a mail survey, a telephone interview, and current sterile urine status. Twenty nine (81%) of 36 patients continued to use CISC after a mean discharge period of 2.9 years (p less than 0.001) with high levels of acceptance. Rao's V discriminant analysis showed success in CISC was affected by the interval between injury and initial self-catheterisation (Canonical Correlation Co-efficient = 1.34). Results of urinalysis for patients continuing CISC were obtained for 18 (62%) patients, 16 (88%) of whom had sterile urine. Implications of these and other findings along with reasons for cessation of CISC are discussed.