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Biomedical subjects

D H Clarke

Publications and source records attributed to D H Clarke.

At least 19 recordsLinked to original sources
PubMed1992

A comparison of strength and muscle endurance in strength-trained and untrained women.

Muscular strength and fatigability of strength-trained (ST) and untrained (UT) women were compared during a 6-min bout of maximal rhythmic exercise involving the elbow flexor muscles given at a rate of 30 contractions.min-1. Fifteen ST and 15 UT subjects, aged 18-34 years and pair-matched for body size, were tested for differences in initial strength, final strength, absolute endurance, relative endurance, and rate of fatigue. Results revealed a significant difference in initial strength, final strength, and absolute endurance in favor of ST subjects. No significant difference was found for relative endurance, and rates of fatigue were similar for both groups. It is concluded that muscular strength and endurance are enhanced in women engaged in a training program designed primarily to increase muscular strength and hypertrophy, but fatigability is not affected.

Adolescent↗
PubMed1992

Muscular strength and endurance as a function of age and activity level.

Muscular strength, endurance, and rate of fatigue were studied in populations of various ages actively engaged in strength and endurance training, as compared with those not engaged in such activities. The strength and fatigability of the elbow flexor muscles were studied for 62 subjects at the ages of 20 (n = 11 active, 10 inactive), 35 (n = 11 active, 10 inactive), and 50 (n = 10 active, 10 inactive) years, tested within 2 years of the appropriate age. They performed a 6-min bout of maximal rhythmic contractions of the dominant arm at a rate of 30 contractions per min. Force applied to the transducer was converted into electrical activity and transmitted to a recorder, where differences in mean values for initial strength, final strength, absolute endurance, and relative endurance were examined for significance. Rates of fatigue and the fatigue curves were also obtained for each group. Results revealed significantly less muscular strength, absolute endurance, and relative endurance as the age of the subjects increased, but no significant difference for age was found in final strength at the conclusion of the exercise bout. Significant differences were found between active and inactive subjects in initial strength, final strength, and absolute endurance in favor of the active subjects. No significant interaction between activity level and age was found for any of the dependent variables. The rates of fatigue were similar for all ages except for the inactive 20-year-old subjects, whose rate of fatigue was markedly slower than that found for all other groups of subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Identification of patients who are at high risk for locoregional breast cancer recurrence after conservative surgery and radiotherapy: a review article for surgeons, pathologists, and radiation and medical oncologists.

PURPOSE: Many retrospective reports have been published identifying risk factors for locoregional (LR) recurrence after breast conservation therapy (BCT). We review these reports, with the purpose of better enabling surgeons, pathologists, radiation oncologists, and medical oncologists to develop strategies for an individualized treatment approach. DESIGN AND RESULTS: English-language retrospective and prospective randomized studies published in the 1980s were reviewed. Histopathologic predictors, young age, extent of conservative surgery (CS), lobular carcinoma, and the impact of adjuvant chemotherapy are all examined as reported risk factors for LR. CONCLUSIONS: Recognition of these factors provides rationale for individualizing the extent of CS based on histopathologic features. In addition, the aggressiveness of radiotherapy (RT) should be dictated by the extent of CS and by identifiable prognostic factors. Strategies are presented for an individualized treatment approach based on a clear understanding of the prognostic factors for LR.

Breast Neoplasms↗
PubMed1992

The effects of treadmill running on the isometric fatigue of the handgrip muscles.

Twelve male subjects, ages 18-32, performed low, moderate, and high intensity systemic treadmill exercise to examine its effect on isometric strength and fatigue of the handgrip muscles. Baseline handgrip values were recorded, as well as maximal oxygen uptake and ventilatory threshold (VT), to determine the intensity for each of the three exercise conditions. Task A involved a 10-min treadmill run at 20% below VT, task B was given at VT, and task C was 20% above VT. Immediately following the endurance treadmill run the subjects were given a 2-min isometric contraction at maximum intensity. Heart rate and blood pressure were also measured. No significant differences were found between control measures and the strength and endurance variables. Rates of fatigue were similar for all conditions, and heart rate and blood pressure remained elevated during the handgrip fatigue task. It is concluded that isometric strength and endurance of non-involved muscles are not affected by prior endurance exercise.

Adolescent↗
PubMed1991

Breast conservation therapy. Severe breast fibrosis after radiation therapy in patients with collagen vascular disease.

Two patients with collagen vascular disease (rheumatoid arthritis and scleroderma) had extremely poor cosmetic results after breast radiation therapy (RT). The patient with rheumatoid arthritis received 5251 cGy at 210 cGy per day, followed by a 1600 cGy iridium-192 implant boost. Between 8 and 11 months post-RT she had severe breast fibrosis, retraction, and pain that required a mastectomy for relief. The patient with scleroderma received 5040 cGy at 180 cGy per day without a boost. Between 1 and 4 months post-RT the systemic symptoms of scleroderma progressed and the breast became hard and retracted. Both rheumatoid arthritis and scleroderma are chronic systemic diseases characterized by severe inflammation and an autoimmune component. The presence of scleroderma at or before treatment should be considered a contraindication to breast RT, whereas the presence of active rheumatoid arthritis should be considered a relative contraindication. An autoimmune mechanism will be presented to explain both the fibrosis and the systemic progression of collagen vascular disease that was observed.

Adenocarcinoma↗
PubMed1990

An overview of brachytherapy in cancer management.

Brachytherapy for cancer patients has been enjoying a resurgence in recent years. The impetus for this renewed interest has been the development of new, more versatile radiation isotopes, new brachytherapy techniques, and the advent of sophisticated computerized dosimetry. The authors present an overview of state-of-the-art brachytherapy.

Brachytherapy↗
PubMed1989

The clinical advantages of I-125 seeds as a substitute for Ir-192 seeds in temporary plastic tube implants.

In August of 1986 at William Beaumont Hospital, Iodine-125 (I-125) seeds were introduced in the clinical practice as a substitute for Iridium-192 (Ir-192) seeds in patients undergoing temporary plastic tube interstitial implants. Through February 1988, 108 I-125 implants were performed in 105 patients. Acute and chronic toxicity was indistinguishable from Ir-192. However, improved radiation safety and a dynamic dosimetric program have resulted from this endeavor. Because of the multiple clinical advantages of I-125, we feel that this should be considered the isotope of choice in temporary interstitial plastic tube implants.

Brachytherapy↗
PubMed1988

The utilization of I-125 seeds as a substitute for Ir-192 seeds in temporary interstitial implants: an overview and a description of the William Beaumont Hospital technique.

In August of 1986, the Department of Radiation Oncology at William Beaumont Hospital (WBH) initiated the routine use of high activity I-125 seeds as a substitute for Ir-192 seeds in temporary implants where the afterloading plastic tube technique was used. Through March 6, 1987, 42 temporary I-125 implants were performed as a boost for curative therapy (38 breasts, 2 sarcomas, 2 tongues). Thus far, we have observed no differences in acute toxicity. Sources ranging from 2 to 5 mCi were utilized. The advantages of I-125 are as follows: (a) Easy to shield; (b) Radiation safety; (c) Decreased exposure to sensitive organs in close proximity to the implanted site; (d) Dosimetric advantages both intrinsic and extrinsic; and (e) Any private room can be used for these patients allowing a central brachytherapy ward to be established. While the advantages were obvious, we anticipated potential disadvantages and shortcomings and these will be discussed in detail. Furthermore because of significant differences in tube and ribbon construction, the I-125 afterloading plastic tube technique has important differences from that technique used with Ir-192. These modifications must be fully understood to maintain the integrity of the I-125 seed-ribbon afterloading tube assembly. A detailed description of the technique will be emphasized.

Brachytherapy↗
PubMed1988

Brachytherapy.

Explore the source record for details and available documents.

Antineoplastic Agents↗
PubMed1986

Cervical carcinoma in women aged 34 and younger.

This presentation addresses three questions concerning invasive cervical carcinoma in women 34 years of age and younger. Is there an increase in the incidence of the disease? Is it more or less susceptible to prevention by cervical screening? Is the clinical behavior different for this age group? Three separate studies are reported: (1) Incidence data in the younger age group have been reviewed at the national, provincial, and local levels. (2) Cytologic screening histories of 125 patients who subsequently developed cervical carcinoma were reviewed. (3) The clinical histories of 121 women 34 years of age and younger, with invasive cervical carcinoma, were reviewed and compared with those of 242 control women 35 years of age and older. Results indicate an increase in incidence in the younger age groups in the three prairie provinces only. Cytologic histories are similar except for an increase in false negative reports in the younger age group. Clinical behavior of the disease is similar for both age groups.

Adenocarcinoma↗
PubMed1985

Analysis of local-regional relapses in patients with early breast cancers treated by excision and radiotherapy: experience of the Institut Gustave-Roussy.

Between 1970 and 1981, 436 patients with T1 and small T2 breast carcinoma were treated by tumor excision followed by radiotherapy at the Institut Gustave-Roussy. The mean follow-up was 5 years, with 50% of patients followed 5 years. Twenty-four patients have experienced a local-regional (LR) relapse for an actuarial LR control rate of 93% at 5 years and 90% at 10 years. Potential prognostic factors for all 24 local-regional recurrences and for the subgroup with relapses in the breast were analyzed. A high Bloom grade and low Nominal Standard Dose (NSD) were significant prognostic factors for predicting LR relapse in both groups. Disease-free survival (from initial presentation) was not adversely affected by a solitary breast recurrence, when patients with successful salvage treatment were considered disease free. However, the group of patients with nodal or dermal recurrences had a much worse prognosis. This paper describes the natural history of breast cancer following a local-regional relapse in irradiated patients without mastectomy. Most importantly, we observed that breast relapses following radiotherapy become clinically apparent more slowly than chest wall failures after mastectomy, and if detected early, that these patients may be successfully retreated.

Adolescent↗
PubMed1982

Virus inoculation in mice bearing Ehrlich ascitic tumors: antigen production and tumor regression.

Ehrlich ascitic carcinoma, as developed in albino mice, has been used as a source of hemagglutinating and complement-fixing antigens, and it proved to be suitable for one type of antigen, or both, for at least 12 viruses of 16 tested. Hemagglutinins were obtained with members of arbovirus groups A, B, and C; complement-fixing antigens were obtained for at least one member of each antigenic group tested. Ehrlich ascitic tumor was compared with sarcoma 180 as a source of antigens; although sarcoma 180 showed many advantages over Ehrlich tumor, the latter gave, in general, better results for complement-fixing antigens. Oncolytic effect with complete recovery of the mice was observed in some instances. The highest recovery rate resulted with Congo and UNA viruses (40%), and the second highest rate resulted with dengue 2, St. Louis, Hazara, and Uukuniemi viruses (20%). The best survival was observed, in decreasing order, with Congo, St. Louis, dengue 2, Tacaribe, Sindbis, Junin, and Amapari viruses.

Animals↗
PubMed1981

A rapid gas chromatographic procedure for the analysis of oxalate ion in urine.

A specific, precise, rapid and sensitive method for the analysis of oxalic acid in urine is described. This microanalytical procedure can detect concentrations of urinary oxalic acid as low as 4 mg/l with a relative standard deviation of replicates of less than 5% (24-h urine collections). 10% BCl3:2-chloroethanol is used to derivatize 0.1 ml of urine after evaporation to dryness or lyophilization. The bis-2-chloroethyl ester of oxalic acid formed is extracted into ethyl acetate/isopropyl ether (1:3, v/v) and is detected by electron capture gas chromatography at the 50 pg level. The total analysis time for 35 samples in 8 h per GC column. A series of determinations of urinary oxalic acid in 21 kidney stone-forming patients resulted in values ranging from 10.6 to 42.0 mg/24 h with a mean recovery of added oxalic acid of 98.2% (range 84.0-111.3%).

Boranes↗
PubMed1980

Physiological characteristics of young well-trained swimmers.

The purpose of this study was to describe body composition, muscular strength, pulmonary function, and aerobic capacity of young swimmers, after 6 years of training. Twelve male members of a competitive swim team, ranging in age for 13 to 16 years, served as subjects. Each subject was measured on 2 separate days at approximately the same time of day on each occasion. On day one, body composition, muscular strength, TLC, FVC, FEV1.0, FRC, RV, and resting DLc0 were determined. On day 2, height, weight, VE max Hr max, and VO2 max were measured. Results indicated that children who train to swim competitively: (1) are lower than average in percent body fat (10.8%) as determined by hydrostatic weighing, (2) are muscularly fit as indicated by the Oregon Cable-Tension Strength Test, and (3) have cardiorespiratory capacities which are greater than one would expect to see in untrained youth of similar ages.

Adolescent↗