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Biomedical subjects

M Evans

Publications and source records attributed to M Evans.

At least 307 records · Page 17Linked to original sources

The association of MHPG to dexamethasone suppression test status.

The results of the dexamethasone suppression test (DST) were compared to levels of 24-hour 3-methoxy-4-hydroxyphenylglycol (MHPG) in 60 patients with unipolar depression. DST nonsuppressors had significantly higher levels of MHPG than did DST suppressors. The possible implications of this finding are discussed.

Adult↗

Efficacies of rapid agglutination tests for identification of methicillin-resistant staphylococcal strains as Staphylococcus aureus.

Four commercially available rapid agglutination tests for the identification of Staphylococcus aureus were compared with the tube coagulase test for the identification of 300 methicillin-resistant isolates of staphylococci. Isolates tested included 207 methicillin-resistant S. aureus and 93 coagulase-negative staphylococci, collected from five medical centers. Strain variability was documented by phage typing and antimicrobial susceptibility patterns. Results of rapid identification tests ranged between 82 and 86% sensitivity, significantly poorer than the 98% sensitivity which the tube coagulase test provided.

Agglutination Tests↗

Bone marrow transplantation for adults and children with poor risk acute lymphoblastic leukaemia in first complete remission.

Thirty-two patients with poor risk acute lymphoblastic leukaemia in first complete remission received bone marrow transplants (BMT) from fully matched family donors. Their ages ranged from 7 to 41 (median 23) years. Nine patients were aged 16 years or less. Patients were selected for BMT because they had risk factors for relapse with standard treatment approaches. In particular the children who were selected for BMT had presenting blast counts of greater than or equal to 90 x 10(9)/l or null immunophenotypes. The overall disease-free survival was 50% with a relapse risk of 31% at 9 years. Patients aged less than 16 years had a much lower risk of both graft-related disease and relapse than did older patients (disease-free survival 89% for those aged 7-16, 48% for those aged 17-26, 24% for those aged 26-41). We conclude that selection of BMT for young patients with poor risk features is entirely justified but that the prognosis for older patients is poor even after BMT.

Adolescent↗

Microbiologic prediction of abdominal surgical wound infection.

We compared two methods of estimating parietal bacterial contamination during abdominal operations. Duplicate swabs were taken from the subcutaneous tissues at the end of 817 operations; one was transported to the Department of Microbiology in Stuart's thioglycollate medium and the other immediately incubated in Robertson's cooked meat broth in the operating room suite and subsequently subcultured. The broth cultures revealed significantly more isolations of potentially pathogenic bacteria and more accurately predicted the likelihood of wound infection. In particular, when visceral cultures were positive, broth culture of wound swabs predicted a major wound infection rate of 0% when sterile, 4.8% when a single pathogenic species was cultured, and 10.1% when two or more were cultured. The corresponding figures for thioglycollate-transported swabs were 1.0%, 10.5%, and 12.9%. We conclude that broth cultures of parietal swabs allow accurate identification of patients at risk of infection from bacterial contamination of the wound during operation.

Abdomen↗

Pre-operative assessment of fitness score.

Death within 30 days or survival after a major operation depends on three things: the severity of the disease and the operation, the technical proficiency of the surgeon and the ability of the patient to withstand both disease and operation. The first of these can be estimated by reference to published figures, the second can only be guessed at and the third has in the past been a matter of subjective judgement. With the aim of producing an objective assessment of the likelihood of survival, we have constructed a score system comprising 26 items including age, chronic disease and acute presenting disease. These items are each given a weight of 1 to 4 and the total fitness score for any patient ranges from 0 (fit) to 10 (unlikely to survive). We have validated this score prospectively in 1517 consecutive patients undergoing emergency or elective major abdominal operations (excluding appendicectomies and hernia repairs). In 492 operations in which the patient scored 0 or 1, one patient died (0.2 per cent); in 290 with scores of 2 or 3, one died (0.3 per cent); in 313 with scores of 4 or 5, five died (1.6 per cent). It was when the score rose to 6 or over that the chances of survival progressively declined: 16 died of the 105 patients who scored 6 (15.2 per cent) as did 74 of the 191 who scored 7 or 8 (38.7 per cent) and 70 of the 126 who scored 9 or 10 (55.6 per cent). We now use the score as part of our audit and enquire particularly closely into the death of any patient with a pre-operative score of less than 6.

Abdomen↗

Peroperative lavage of the obstructed left colon to allow safe primary anastomosis.

A series of 44 patients with complete or partial left-colon obstruction underwent laparotomy and intraoperative colonic lavage. Irrigation was unsuccessful in three, the operation being concluded by a Hartmann resection. In the remaining 41, the achievement of an empty colon allowed primary anastomosis after resection of the obstructing lesion. Seven patients (17.1 percent) died, none of dehiscence of the colorectal anastomosis, although minor anastomotic leaks occurred in four. The median postoperative hospital stay was 12 days. Two patients developed peritonitis (one fatal) from leakage of ileal contents when the irrigating catheter was introduced through an ileotomy and retained postoperatively, and this aspect of the technique is not recommended. The operation offers a single-stage alternative for patients with unprepared or ill-prepared bowels who require resection of left-colon lesions. The results compare favorably with the authors' previous experience of two- or three-stage resections (in-hospital mortality rate, 42 percent).

Aged↗

The inadequacy of published random control trials of antibacterial prophylaxis in colorectal surgery.

Fifty-six papers published between 1979 and 1986 that tested regimens of antibacterial bowel preparation before elective colorectal operations were studied using a numerical score devised for assessing publications of random control clinical trials. A maximum score of 100 was allotted: 50 for 15 aspects of design, 30 for ten aspects of analysis, and 20 for eight aspects of presentation. The 56 papers scored from 33 to 89, (mean, 61.6, standard deviation, 11.9). Only 13 (23 percent) reached a score of more than 70. The most frequent errors in design were the use of placebos in the control group (27 percent) and faulty methods of randomization (36 percent). Errors in analysis resulted in penalization of more papers than any other aspect; these included the almost universal omission of confidence limits, confusion of exclusions and withdrawals (46 percent), not recording the fate of withdrawals (80 percent) and incorrect use of statistical tests (55 percent). Ten papers reported results showing important clinical differences that did not achieve statistical significance, but only two mentioned the Type II error. Defects in presentation were less frequently encountered; the most common were inaccessibility of raw data (66 percent), lack of sufficient information to allow replication of methods (43 percent), and the drawing of firm conclusions from shaky data (50 percent). It was particularly disappointing that no evidence of improvement in the standard of these reports over the seven years studied was found.

Anti-Bacterial Agents↗

Disposition of vitamin E in the eye.

To study the effect of exogenous vitamin E on its plasma and eye tissue levels, we administered 100 mg/kg of dl-alpha-tocopherol either by intravenous, intramuscular, or oral routes in 3-day-old newborn kittens. Controls did not receive the drug. alpha-Tocopherol levels in the plasma, retina, choroid, and vitreous were analyzed by high-performance liquid chromatography at selected intervals following drug administration. Our results showed that after intravenous administration of vitamin E, the retinal alpha-tocopherol levels increased 300 and 500% the baseline value at 2 and 4 h, respectively. By contrast, comparable retinal levels were achieved at 24 h following intramuscular administration and 72 h following oral administration. In the intravenous group high retinal levels were maintained up to 168 h, while in the intramuscular and oral groups retinal levels continued to increase up to 192 h. Irrespective of route of administration, the retinal concentration of alpha-tocopherol remained high even when the plasma levels were declining; plasma levels did not reflect retinal levels at any time. Following exogenous vitamin E administration, alpha-tocopherol levels increased both in the choroid (4 to 6 times the control) and in the vitreous (1.5 to 4 times the control). Significant differences in tocopherol levels were also seen between the eyes in the same animal in all groups. Our studies suggest a single dose of vitamin E by intravenous, intramuscular, or oral routes increases retinal levels from 3 to 5 times the control levels. However, peak retinal levels are achieved earlier by parenteral than by the oral route.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Anti-idiotypic antibody against anti-DNA in sera of laboratory personnel exposed to lupus sera or nucleic acids.

We tested for anti-DNA, anti-idiotypic, antinuclear, and lymphocytotoxic antibodies in the sera of three groups of normals: volunteers never exposed to lupus sera or nucleic acids (group I), research personnel handling nucleic acids (group II), and laboratory personnel handling lupus sera (group III). There was no significant differences among the groups with respect to levels of either single stranded or double stranded anti-DNA. Group I showed no significant differences in binding to F(ab')2 fragments of lupus anti-DNA, lupus non-anti-DNA or normal IgG. Compared to group I, groups II and III bound significantly higher to anti-DNA F(ab')2 fragments compared to non-anti-DNA F(ab')2 or normal F(ab')2 fragments. Sera from the three groups were negative for antibodies and all but one individual from group III had normal antinuclear antibody titres. These results indicate that sera of normals exposed to lupus sera or to nucleic acids contain an anti-idiotype directed against anti-DNA antibody. The possible role of these anti-idiotypes in regulating the anti-DNA antibody is discussed.

Antibodies, Anti-Idiotypic↗

Effect of controlled axial micromovement on healing of tibial fractures.

The preliminary results are presented from a study in which 85 serious tibial fractures were treated with external skeletal fixation. In group I patients were treated with highly rigid fixation. In group II the same fixation was used but axial micromovement was applied across the fracture site for 30 min per day, starting 1-3 weeks after injury and continuing until partial weight-bearing, which leads to self-induced movement. The overall mean time to independent weight-bearing was longer in group I than group II (p = 0.02); delayed union occurred in more group I patients. Objective measurement of fracture stiffness was made by means of strain gauges placed on the fixation frame for 49 fractures treated consecutively. The time to reach stiffness levels equivalent to clinical union was significantly longer in group I than in group II. The fractures in the treatment groups were of comparable severity. It seems that the fracture healing process is susceptible to small changes in mechanical environment.

Fracture Fixation↗