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Biomedical subjects

S McDonald

Publications and source records attributed to S McDonald.

At least 109 records · Page 6Linked to original sources
PubMed1989

Second malignant tumors in patients with laryngeal carcinoma: diagnosis, treatment, and prevention.

Although the survival rates reported for patients with larynx carcinoma are quite good, there is a risk of developing second malignant tumors (SMT) in this population. The prognosis for SMT is poor, particularly with tumors of the lung and esophagus. The Rochester series was analyzed for larynx stage and specific SMT sites, possible common etiologic factors, and survival of the population as a whole, as well as for the SMT group. From a total of 235 patients with larynx carcinoma and a median follow-up of 10 years, 50 patients with 61 SMT were identified. The overall incidence of developing a SMT was 21%, with 44% of the SMT in the lung. The median survival from SMT diagnosis was 8.74 months and the 2-year survival was only 26%. More than twice as many SMT were observed than would be expected in the population at risk, with an observed-to-expected ratio (OER) for lung SMT of 5.3, and 8 times as many head and neck SMT occurring in our population. These SMT are not treatment related but are most likely caused by a combination of exposure to a common carcinogen, that is, tobacco smoke and alcohol, and to inherent factors, notably "condemned mucosa syndrome." Follow-up procedures, from the perspective of SMT development in larynx cancer patients, are addressed in an attempt to improve survival. The focus of this study is the high incidence of lung primaries that could be mistaken for metastatic disease, which is relatively uncommon in early larynx cancer patients.

Adult↗
PubMed1989

Serum markers for prediction of pulmonary radiation syndromes. Part I: Surfactant apoprotein.

Detection of a biochemical marker indicating radiation lung injury prior to the onset of clinical pathologic events could prove valuable in patient management. An increased level of alveolar surfactant is one of the earliest detectable changes following lung irradiation, starting within hours of irradiation and persisting a maximum of 2-6 weeks. However, because broncho-alveolar lavage is impracticable and endothelial cell damage due to radiation results in changes in permeability of vessel wall with leakage of alveolar proteins into serum, identification of serum markers was sought. A series of experiments in rabbits are described that clearly demonstrate serum surfactant apoprotein is an accurate marker and predictor for later lethal radiation pneumonitis. At 3-7 days after graded single doses to lung, surfactant was found in the serum paralleling the dose response for lethality. Control studies with a physiologic agent such as terbutaline release alveolar surfactant, but no serum surfactant was detected. Monitoring serum surfactant could direct preventive intervention prior to clinicopathologic manifestation of pulmonary radiation syndromes.

Animals↗
PubMed1989

Efficacy of debridement and primary closure of contaminated wounds: a comparison of methods.

Proper management of highly contaminated traumatic wounds frequently requires delayed primary closure of healing by secondary intention to prevent subsequent infection. This animal study compares the efficacy of various wound debridement methodologies to prevent infection following primary closure of treated contaminated wounds. Forty-four Sprague-Dawley rats with uniform, paravertebral incisions were studied. Each wound was inoculated with a standard amount of Staphylococcus aureus bacteria and allowed to remain open for two hours. Each wound was treated before wound closure by one of four debridement methods: (1) surgical scrubbing, (2) high-pressure irrigation, (3) ultrasonication, or (4) soaking. The control animals' wounds were closed without debridement. At 7 days, each animal was evaluated for the presence of gross infection and wound induration. Ultrasound, with a 25% incidence of gross infection, compared with irrigation (75%), scrubbing (82%), and soaking (89%) provided significant protection from subsequent abscess formation. The control group uniformly developed infection (100%). The average amount of induration after ultrasonication (1.35 +/- 0.56 cm) was also significantly less than irrigation (2.07 +/- 0.75 cm), scrubbing (1.95 +/- 0.34 cm), and soaking (1.73 +/- 0.22 cm). Our data demonstrate that ultrasonic wound debridement has exciting potential as a new debridement technique for contaminated traumatic wounds.

Animals↗
PubMed1989

Cyclic Cushing's disease in association with a pituitary stone.

We have documented what we believe to be the first reported case of a pituitary stone in a patient with pituitary-dependent Cushing's disease. Pituitary stones have been reported exclusively in growth-hormone-producing or prolactin-producing pituitary adenomas. Our patient's ACTH and serum cortisol levels cycled for 15 months and then resolved spontaneously. A CT scan of the head showed calcification of pituitary tissue. Pituitary stones may occur in association with Cushing's disease. We hypothesize that the spontaneous resolution of the cyclic Cushing's disease was due to destruction and ultimate calcification of abnormal pituitary tissue.

Adenoma↗
PubMed1989

Cognitive impairment after neuroleptanalgesia in cataract surgery.

This study was undertaken to evaluate the mental recovery of patients following cataract operations under neuroleptanalgesia. Mental function was assessed by Mini-Mental State (MMS) preoperatively and at 6 and 24 hours postoperatively. Preoperatively, 18.7% of the elderly had cognitive impairment of mental function while none in the younger group had any impairment (P less than 0.02). At six hours postoperatively, 29.7% of the elderly had cognitive impairment compared with 4% of the younger group (P less than 0.01). At 24 hours postoperatively, the percentage of elderly and younger patients with cognitive impairment had returned to preoperative levels. Baseline score and age were found to be significant predictors (P less than 0.004) of the 6-hour score and 24-hour score. In conclusion, cognitive impairment of mental function occurred in patients undergoing cataract operation with retrobulbar block and intravenous sedation at 6 hours postoperatively; MMS has the potential for use as a screening preoperative test for outpatients to identify those at risk for developing cognitive impairment.

Adult↗
PubMed1988

Adverse effects of brain irradiation correlated with MR and CT imaging.

Forty-one patients treated for primary malignancies of the brain at the University of Rochester Cancer Center since 1970 were assessed for adverse effects of irradiation clinically, and by computerized tomography (CT) and magnetic resonance (MR) imaging. At diagnosis, patients ranged in age from 1-65 years (median 19 years) and the most common tumor (in 30) was astrocytoma. Radiation doses ranged from 45 to 81.3 Gy (median 56.8 Gy). White matter changes visible on MR were graded on a scale of 1-4, with grades 1-2 known to occur in some normal patients. Areas of increased signal intensity not associated with the tumor or surgery were visible in all patients (gr 1 = 37%, gr 2 = 32%, gr 3 = 17%, gr 4 = 15%) whereas only 35% had regions of abnormality (hypodensity) on CT. Sulci enlargement and ventricular abnormalities (asymmetry or dilatation) were present in approximately 50% of patients by each technique. Higher grade MR lesions were associated with radiation to large volumes and high doses. For the 36 patients treated with 1.5-2.0 Gy daily fractions, the mean radiation dose by grade was as follows: gr 1 = 55.1 Gy, gr 2 = 58.8 Gy, gr 3 = 60.0 Gy, gr 4 = 63.5 Gy. All 5 patients treated on a hyperfractionated schedule had gr 1-2 changes despite receiving greater than 70 Gy. Fifty percent of patients treated to the whole brain (+/- boost) had gr 3-4 changes, compared with 14% treated with local fields (peak dose regions similar in both groups). Among the children (less than or equal to 13 years), 20% had gr 3-4 changes compared with 56% of adults (excluding hyperfractionated patients). This finding may be due entirely or in part to the lower radiation doses used for children (mean 54.4 Gy vs. 63.7 Gy in adults). Clinical abnormalities attributable to irradiation included an impairment in mental functioning in 7 adults, and learning disabilities in 5 children. Five of these adults (71%) had gr 3-4 changes on MR as compared to gr 3-4 changes in 29% of the remaining adult group. Five patients developed seizure disorders. We conclude that adverse effects of brain irradiation are more sensitively imaged by MR than CT and that these abnormalities are associated with larger treatment volumes and either (or both) higher doses or older age. Conversely, some patients treated with high radiation doses have unremarkable changes on MR, and others have severe white matter changes which are not clinically expressed.(ABSTRACT TRUNCATED AT 400 WORDS)

Astrocytoma↗
PubMed1988

Effects of stock differences in the acceleration of puberty in female mice.

Newly born TO strain female mice were exposed daily to the urine from male albino mice of the same and CFLP strains, from feral mice carrying Robertsonian translocation chromosomes and to water as a control condition. At 21 days of age, when exposure was discontinued, there were differences in body weight between treatments which were not present when adult. Exposure to urine from mice with Robertsonian translocations did not accelerate puberty and the interval between vaginal opening and first oestrus was longer (4.2 days) than in mice exposed to the urine from the albino strains (1.8 days). Mice exposed to the urine from the Robertsonian stock were in dioestrus more often than those exposed to the urine from laboratory strains. The Robertsonian mice also differed in their behaviour in an open arena in that they passed fewer faecal pellets than those exposed to the urine from the albino mice. The water control mice defecated the least frequently. The mice exposed to the Robertsonian urine were less active than the laboratory strains but the differences did not reach an acceptable level (P less than 0.06) of significance.

Animals↗
PubMed1987

Simultaneous radiation therapy and cisplatin chemotherapy in advanced cancer of the head and neck. A pilot study at Tygerberg Hospital, Parowvallei, South Africa.

Fifty patients with advanced carcinoma of the head and neck were treated in a nonrandomized pilot study utilizing simultaneous cisplatin and radiotherapy. Treatment was delivered in two segments. The initial partial course (PC) consisted of 75-100 mg/m2 of cisplatin and concomitant radio-therapy to 20.00 Gy in 1 week, with 4-week split. Patients who tolerated therapy and experienced at least a partial response (PR) went on to complete the full course of therapy (FC), with the second phase consisting of 120 mg/m2 of cisplatin and 38.40 Gy of radiation. Total cisplatin delivered ranged between 195 and 220 mg/m2, and the total radiation dose was 58.40 Gy. Of 38 evaluable patients, 31 (82%) had at least a partial response (PR). However, at time of analysis 20 months after study, 27 (71%) patients were alive with disease or dead. Mean disease-free survival (DFS) for patients receiving FC therapy (10.05 months) was greater than that for patients who received only PC therapy (2.65 months), but the difference in overall survival (OS) was not statistically significant (11.95 FC versus 10.29 PC). Response rates and the minimal toxicity are within the range of other reported studies. Randomized studies should seek optimal time-dose schedule and establish advantages in terms of crude survival and disease-free survival.

Adolescent↗
PubMed1987

A major challenge in cancer therapy: metastasis.

Although metastasis remains a major cause of death, current therapeutic techniques used in the management of malignant disease are usually effective in achieving primary tumor control. There are many important issues to be considered in the management of pulmonary metastasis. Some of the more important issues, which will be discussed, include solitary v multiple metastases, when is cure possible, prognostic signs, and palliation.

Humans↗
PubMed1986

An investigation of the ability to process inferences in language following right hemisphere brain damage.

Twenty-two right hemisphere brain-damaged and 22 non-brain-damaged patients were given a multiple-choice recognition task which contained true statements, statements which were inferentially true but not actually heard before, and false statements. It was hypothesized that if right hemisphere brain damage disturbs the ability to comprehend inferences, these subjects, unlike their normal counterparts, would not falsely recognize true inferences as heard before. This hypothesis was not confirmed. However, the right hemisphere group was poorer than controls at rejecting false statements. This behavior was speculated to be a retrieval difficulty, which was exacerbated if the information contained spatial or semantically similar material.

Adult↗
PubMed1984

Comparison of subjects' perception of inspiratory and expiratory resistance.

Six healthy male adults were studied at five levels of suprathreshold added resistance (delta R) applied thrice to either inspiration (I) or expiration (E) in a random sequence. Subjects squeezed on isometric handgrip dynamometer to express the perceived magnitude of the load. Peak mouth pressure (Pm), flow, grip (G), and delta R were analyzed to derive the exponent for Steven's power law. We observed that the slope for log G vs. log delta R was significantly greater for I loads than for E loads (P less than 0.05), but the intercepts for E loads were significantly elevated. However, the slopes and intercepts for log G vs. log Pm during the same I and E loads were not significantly different. When subjects were instructed to target I or E flow to a preset level, we observed no difference between the slopes and intercepts for log G vs. log delta R during I and E loading. These results suggest that 1) the sensory information utilized in judging the magnitude of added resistance is more likely related to the force generated by the respiratory muscles (Pm) rather than delta R per se; and 2) similar muscle receptors and neural processing systems are utilized in the estimation of added loads involving either inspiratory or expiratory muscle groups.

Adult↗
PubMed1984

Management of a broken needle in the pterygomandibular space: report of case.

The management of a broken short 30-gauge hypodermic needle after an inferior alveolar dental nerve block in a 3-year-old child is discussed. Because of the possibility of the needle migrating toward vital structures, and because of the psychologic and medicolegal implications that could arise, we believed that the needle should be immediately removed with surgical procedures.

Anesthesia, Dental↗
PubMed1984

Intraperitoneal prolene mesh in hernia repair: a comparison of two techniques.

Prolene (polypropylene) mesh is a useful material for technically difficult repairs of abdominal wall hernias. In this study, two insertion techniques were used and compared. The first method, in which 2-cm wide strips of mesh were cut perpendicular to the main part, pulled through the musculoperitoneal layer and anchored to the anterior fascial layer, was abandoned after use in 10 patients because of complications. The second method, using circumferential horizontal mattress sutures to anchor the mesh, gave satisfactory results in the 40 patients in whom it was used. There were no deaths, and complications were few and easily dealt with.

Female↗