Biomedical subjects

C S McDonald

Publications and source records attributed to C S McDonald.

4 recordsLinked to original sources

PubMed2000

Pulmonary toxicity of induction chemotherapy prior to standard or high-dose chemotherapy with autologous hematopoietic support.

We closely followed the pulmonary function of 150 consecutive high-risk breast cancer patients who underwent standard induction CAF (cyclophosphamide, doxorubicin, 5-fluorouracil) chemotherapy, followed by randomization to either standard-dose CPB (cyclophosphamide, cisplatin, bischloroethylnitrosourea [BCNU]) chemotherapy (SDC) or to high-dose CPB chemotherapy (HDC) with autologous bone marrow transplantation (ABMT) and peripheral blood progenitor cell support (PBPCS). Previously, we have described a delayed pulmonary toxicity syndrome (DPTS) which characterizes the pulmonary dysfunction after HDC and ABMT in this patient population. However, little is known concerning the role induction chemotherapy plays in its development. We found that after three cycles of induction CAF, the mean diffusing capacity of the lungs for carbon monoxide (DL(CO)) significantly decreased by 12.6%. Additionally, in patients receiving HDC, the mean DL(CO) further decreased to a nadir of 55.2 +/- 14.1% which was significantly lower than those receiving SDC (nadir: 80.7 +/- 12.3%). DPTS occurred in 72% of patients receiving HDC as compared with only 4% of patients receiving SDC. All individuals diagnosed with DPTS were treated with prednisone and the 2-yr follow-up of pulmonary function revealed a gradual improvement in mean DL(CO) such that there were no differences between HDC and SDC groups at the end of the study. No mortality was attributable to pulmonary toxicity in either group. After induction chemotherapy, but before HDC, bronchoalveolar lavage (BAL) demonstrated significant elevations in interleukin-6 (IL-6), IL-8, neutrophils, and lymphocytes. We conclude that induction CAF produces asymptomatic pulmonary dysfunction and inflammation which may prime the lungs for further injury by HDC and predispose to the development of DPTS. Fortunately, in this specific ABMT patient population, the early and judicious use of prednisone appears to improve pulmonary function in patients who develop DPTS.

Adenocarcinoma↗

PubMed1987

Age differences in autonomic variables during sleep.

Relationships of autonomic variables and sleep were assessed in men and women at two age levels (18 to 23 and 57 to 71 years) to check for alleged associations between physiological arousal and age-related sleep disturbance. Heart rate, although relatively high at the upper age level, was unrelated to sleep measures. For the most part, underarousal rather than hyperarousal characterized older sleepers. Women's body temperature declined significantly with age. Vasoconstrictions, which were more frequent in young adults, showed some association with better sleep. The earlier the overnight temperature nadir, the more wakefulness after sleep onset. Together with other studies, this suggests that an age-related phase advance in the temperature rhythm disrupts sleep. These results are at odds with the view that sympathetic hyperactivity associated with elevated plasma norepinephrine causes age-related sleep disturbance.

Adult↗

PubMed1984

Effects of age on auditory awakening thresholds.

Auditory awakening thresholds ( AATs ) were assessed in sleeping men and women at three age levels (18 to 25, 40 to 48, and 52 to 71 years) with a procedure that employed a 5-sec tone in accordance with the up-and-down method. Although age was less influential than individual differences in predicting AAT levels, there was a significant and substantial AAT decline from early adulthood to later life in Sleep Stages 4, 2, and REM. With no variation by sex, this progressive decline was apparent by the 40s in Stages 4 and 2 and was sharpest from one age level to another in Stage 4. Decline was more gradual and delayed in REM, probably because of a sampling artifact based on stimulus incorporation in dreams. These findings help to explain increased sleep disturbance in the later years as a result of diminished intensity of sleep, which makes sleep more difficult to sustain.

Adult↗

PubMedDate not supplied

High signal on T1-weighted MR images of the head: a pictorial essay.

T1-weighted magnetic resonance images (T1WI) of the head may manifest high signal in many normal and pathologic situations. Normally, it may be seen in fatty tissues, certain artifacts, and in areas without a blood-brain barrier after gadolinium administration. It is also seen in the posterior pituitary gland and in certain instances in the anterior pituitary gland. Pathologically, it may occur in many lesions after gadolinium enhancement, in fatty and cystic lesions, and in lesions with paramagnetic content. Occasionally, it may be seen in calcium deposition. Many of these are described and illustrated.

Artifacts↗