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Biomedical subjects

M D Evans

Publications and source records attributed to M D Evans.

At least 19 recordsLinked to original sources
PubMed1992

Cognitive therapy and pharmacotherapy for depression. Singly and in combination.

Cognitive therapy and imipramine hydrochloride tricyclic pharmacotherapy, each singly and in combination, were compared in the treatment of nonpsychotic, nonbipolar depressed outpatients. One hundred seven patients were randomly assigned to 12 weeks of active treatment; 64 patients completed the full course of treatment. Rates of attrition were high but not differential. Cognitive therapy and pharmacotherapy did not differ in terms of symptomatic response, either in the primary analyses or in secondary analyses restricted to more severely depressed outpatients. Initial severity did predict response within pharmacotherapy alone, but not within cognitive therapy. Combining cognitive therapy with pharmacotherapy did not markedly improve response over that observed for either modality alone, although such nonsignificant differences as were evident did favor the combined treatment. Two patients died as a consequence of suicide attempts, both of which involved study medication.

Adolescent↗
PubMed1992

Differential relapse following cognitive therapy and pharmacotherapy for depression.

Patients successfully treated during a 3-month period with either imipramine hydrochloride pharmacotherapy, cognitive therapy, or combined cognitive-pharmacotherapy were monitored during a 2-year posttreatment follow-up period. Half of the patients treated with pharmacotherapy alone continued to receive study medications for the first year of the follow-up. All other patients discontinued treatment at the end of the acute treatment phase. Patients treated with cognitive therapy (either alone or in combination with medication) evidenced less than half the rate of relapse shown by patients in the medication--no continuation condition, and their rate did not differ from that of patients provided with continuation medication. It appears that providing cognitive therapy during acute treatment prevents relapse. Whether this preventive effect extends to recurrence remains to be determined.

Adolescent↗
PubMed1992

A simple technique for film dosimetry.

Dose distributions showing the effect of custom made compensators may be produced using measured data unique to the compensator. A fast method of obtaining this data with film is described. The problem of dose versus density response is avoided by an appropriate choice of the given dose to the film.

Body Constitution↗
PubMed1992

Examination of pre- and posttreatment MHPG during cognitive therapy.

Sixteen unipolar depressed patients were treated with cognitive therapy for 12 weeks. Pretreatment 24-hour urinary MHPG levels were unable to predict treatment response. There was a nonsignificant trend for cognitive therapy responders to show a decrease in MHPG during treatment when compared to nonresponders.

Adult↗
PubMed1991

Response of depression to very high plasma levels of imipramine plus desipramine.

Forty-five depressed patients were treated with imipramine for 6 weeks. Seven of 7 patients (100%) who had plasma levels of imipramine plus desipramine greater than 500 ng/ml showed a 50% or greater improvement in Hamilton depression scores compared with 23 of 38 patients (60%) with plasma levels less than 500 ng/ml (p less than 0.057).

Adult↗
PubMed1991

Aqueous cigarette tar extracts damage human alpha-1-proteinase inhibitor.

The elastase inhibitory capacity (EIC) of human alpha-1-proteinase inhibitor (alpha 1PI) is severely compromised by aqueous cigarette tar extract (ACTE). An aqueous extract of the tar from two cigarettes causes a loss of EIC of at least 60% in 24 h at 37 degrees C (pH 7.4) and the damaging capability of the ACTE is retained for many hours. Hydrogen peroxide appears to be an essential component of the mechanism by which ACTE damages alpha 1 PI, since catalase substantially protects alpha 1PI from ACTE-mediated damage. Only mild protection is offered by 10 mM diethylenetriamine pentaacetic acid, indicating only a minor role for transition metal ions in the alpha 1PI-damaging process. Hydroxyl radicals are unlikely agents of alpha 1PI damage in the ACTE system, as judged from hydroxyl radical scavenger studies. Ascorbate and various thiols offer protection to different degrees, dependent on the incubation conditions. Of several amino acids tested, cysteine and methionine (but not methionine sulfoxide) are the only two that protect alpha 1PI. We suggest that components of cigarette smoke particulate matter extracted into the aqueous lung fluid environment may cause local deficiencies in alpha 1PI in smokers' lungs.

Amino Acids↗
PubMed1991

High dose rate afterloading intracavitary therapy in carcinoma of the cervix.

From January 1984 through December 1986, 87 patients with previously untreated carcinoma of the cervix received external beam pelvic irradiation and high dose rate intracavitary therapy (HDRT). There were 18 Stage IIA patients, 39 Stage IIB, and 30 Stage IIIB. The median age was 60 years and the median follow-up time was 42 months for patients at risk. Radiotherapy consisted of external megavoltage irradiation to the whole pelvis (median dose 4600 cGy) combined with one (6 patients), two (51 patients), or three (30 patients) HDRT insertions. A high dose rate remote afterloading unit with 60Co sources was used to deliver the HDRT. The prescribed dose to point A was between 800 and 1000 cGy per treatment. The dose rate at point A initially was approximately 150 cGy/min and dropped to approximately 100 cGy/min during the duration of the study. Treatments with multiple fractions were given at weekly intervals. The overall actuarial survival at 5 years was 88% for Stage IIA, 64% for Stage IIB and 32% for Stage IIIB patients. Pelvic recurrence remained the major cause of failure. Grade III and IV late complications included proctitis and bowel obstruction in six patients each. We conclude that HDRT results are similar to those obtained with conventional low dose rate intracavitary systems. HDRT is cost effective and minimizes exposure to personnel. Several questions, such as the total number of insertions required, dose per HDRT insertion, and optimal HDRT insertion schedule remain unanswered and further experience is needed to better clarify these issues.

Adult↗
PubMed1990

A comparison of the free radical chemistry of tobacco-burning cigarettes and cigarettes that only heat tobacco.

Cigarette smoke contains free radicals both in the particulate matter (tar) and in vapor-phase smoke. Vapor-phase smoke decreases the activity of alpha-1-proteinase inhibitor (alpha 1PI) in vitro. The free radical content of the tar and vapor-phase smoke from a cigarette that heats rather than burns tobacco has been compared with data on a standard 1R4F cigarette. No radicals were detected in the tar from the new cigarette and radicals in its vapor-phase smoke are lower by more than 99% relative to the 1R4F standard cigarettes. The vapor-phase smoke from the new cigarette causes essentially no reduction of alpha 1PI activity in vitro. These findings support our previously published mechanisms for the production of radicals in tar and in vapor-phase smoke.

Free Radicals↗
PubMed1990

How does cognitive therapy work? Cognitive change and symptom change in cognitive therapy and pharmacotherapy for depression.

The effects of changes in depression-relevant cognition were examined in relation to subsequent change in depressive symptoms for outpatients with major depressive disorder randomly assigned to cognitive therapy (CT; n = 32) versus those assigned to pharmacotherapy only (NoCT; n = 32). Depression severity scores were obtained at the beginning, middle, and end of the 12-week treatment period, as were scores on 4 measures of cognition: Attributional Styles Questionnaire (ASQ), Automatic Thoughts Questionnaire (ATQ), Dysfunctional Attitudes Scale (DAS), and the Hopelessness Scale (HS). Change from pretreatment to midtreatment on the ASQ, DAS, and HS predicted change in depression from midtreatment to posttreatment in the CT group, but not in the NoCT group. It is concluded that cognitive phenomena play mediational roles in cognitive therapy. However, data do not support their status as sufficient mediators.

Adolescent↗
PubMed1989

Alignment modification for pencil eye shields.

Accurate alignment of pencil beam eye shields to protect the lens of the eye may be made easier by means of a simple modification of existing apparatus. This involves drilling a small hole through the centre of the shield to isolate the rayline directed to the lens and fabricating a suitable plug for this hole.

Eye↗
PubMed1988

Standard compensators for ENT therapy fields.

Radiotherapy of the ENT region is frequently applied through two parallel-opposed, lateral fields covering a volume from the maxillary sinus to the base of the neck, with the isocentre close to the angle of the mandible. The large variation in separation throughout this volume, in both the transverse and the coronal planes, leads to field inhomogeneities which are often resolved by the use of custom designed, two-dimensional compensators. This paper presents an alternative method of compensation using a set of one-dimensional, standard compensators applied in the coronal plane which, in conjunction with a wedge in the transverse plane, yields a uniform distribution throughout the treatment volume for the majority of patient configurations. The advantages of this technique are the immediate availability of a computerised treatment plan incorporating the compensator, an increase in the dose homogeneity obtainable over that without compensation and the elimination of any delay which may be incurred by the design and fabrication of custom made compensators.

Head and Neck Neoplasms↗
PubMed1988

Rectal and oesophageal treatment by the Selectron High Dose Rate afterloader.

Rectal and oesophageal intracavitary treatments have been administered by the Selectron High Dose Rate afterloader. The treatment time is of the order of a few minutes which makes the use of a high dose rate advantageous as compared to medium and low dose rate procedures. Localizing techniques as well as dosimetry are discussed.

Brachytherapy↗
PubMed1987

Dose distributions around selectron applicators.

Measured and calculated dose distributions around selectron applicators, loaded with 60Co high dose rate pellets, are presented. The effect of the stopping screw, spacers, pellets themselves and the applicator wall on the dose distribution is discussed. The measured dose distribution is in almost perfect agreement with the calculated distribution in planes perpendicular to the applicator axis and containing a source. On the applicator axis directly below the applicator the measured dose amounts to about 75% of the calculated value, when only the stopping screw attenuates the beam from a pellet. When the beam is attenuated by spacers in addition to the stopping screw, the discrepancy between the calculated and measured dose may exceed 50%. Clinically relevant source geometries are also discussed. It is shown that for most regions around the applicator the method of a simple addition of dose contributions from individual point sources is an acceptable approximation for the calculation of dose distributions around the selectron applicators.

Brachytherapy↗