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Biomedical subjects

G Stewart

Publications and source records attributed to G Stewart.

At least 91 records · Page 5Linked to original sources
PubMed1994

Fine-needle aspiration cytology in locally advanced breast adenocarcinoma: a case with complete response to preoperative chemotherapy in association with granulomatous inflammatory reaction.

Preoperative chemotherapy for locally advanced breast carcinoma (stage IIIA,B) is increasingly utilized demonstrating a 70 to 95% objective response and 15 to 35% complete response. A 70-yr-old woman presented with a 9 cm left upper outer quadrant breast mass associated with overlying skin redness and a 2.5 cm left axillary mass. Fine-needle aspiration cytology (FNA) showed a pleomorphic adenocarcinoma in both the breast and axilla. Following three courses of chemotherapy with cyclophosphamide, methotrexate, and 5-fluorouracil (CMF), the patient had a dramatic clinical reduction of tumor, reduction of serum CA 15-3 from 161 to 64 U/ml, and underwent a modified radical mastectomy and axillary dissection. The specimen showed no viable tumor in association with an extensive granulomatous response in both the breast and axillary lymph nodes. This case illustrates two points concerning preoperative chemotherapy for locally advanced breast cancer: (1) The role of FNA v. tissue biopsy is examined. Positive cytology must be conclusive since, as in this case, no viable carcinoma may be present after therapy. (2) Chemotherapy induced host tissue reaction has not been extensively studied. This case showed a remarkable granulomatous reaction in association with tumor elimination. Since this reaction was not present on the original aspiration cytology slides, the chemotherapy treatment must have induced this reaction. Mechanisms for creating this effective host response need further investigation.

Adenocarcinoma↗
PubMed1994

Pediatric emergency department walk-outs.

The objectives of this study were to determine reasons for leaving a pediatric emergency department before physician evaluation, any adverse outcomes of those leaving, and to assess whether the presence of an ombudsman altered the pattern. This was a prospective follow-up study of all patients who left the pediatric emergency department of the Children's Hospital of Michigan before physician evaluation between October 24, 1991 and January 30, 1992. Information was obtained from medical records and a telephone questionnaire with the parent or guardian one week later. A control group of patients (n = 150) evaluated in the same period were randomly selected for comparison and matched for triage acuity score, shift, and weekday/weekend visit. Five hundred and twelve patients left during this period. Contact was made with 82% (419). Forty-three percent of patients left only because of a long wait, and an additional 19% included a long wait as one of the reasons for leaving. There was a significantly longer waiting time for walk-outs compared with controls (188 +/- 76.4 vs 93.6 +/- 64.9 minutes, P < 0.0001). Of the 419 patients followed, 256 (61%) were seen by a physician within seven days, and seven (1.7%) were hospitalized. Three hundred one (72%) were reported to be well; 108 (26%) were better. No deaths occurred. Hospitalization rates were significantly lower for patients who left compared with patients who stayed over the same period of time (7/419 vs 1931/16,990, P < 0.0001). The presence of an ombudsman was associated with an increase in walk-outs.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1994

Legionnaires' disease outbreak, Fairfield 1992: public health aspects.

An investigation of an outbreak of Legionnaires' disease in 1992 in Fairfield, a municipality of Sydney, was carried out to determine the source of the outbreak. Cases of Legionnaires' disease with onset of symptoms between 11 and 20 April 1992 were included. Definite cases were individuals with a history consistent with Legionnaires' disease, confirmed by direct fluorescent antibody testing plus serology or culture. There were two control groups: patients admitted to the same hospital as the cases, matched for age and sex, and patients admitted to hospital with a presumptive diagnosis of legionnaires' disease, in whom the diagnosis was subsequently excluded. There were 26 definite cases with onset of symptoms between 11 and 20 April 1992. Six (23 per cent) died. Twenty-two cases (85 per cent) reported visiting the Fairfield business district during the ten days prior to the onset of symptoms. They were 20 times more likely to have visited Fairfield than were matched controls. Matching of Legionella pneumophila serogroup 1 from environmental and clinical samples was achieved by cytogenetic fingerprinting. Fourteen cases were linked to a single environmental sample. The epidemiological findings were consistent with a point source of Legionella in the Fairfield business district. It is most likely that the exposure occurred on 10 April 1992.

Adult↗
PubMed1993

Scaphoid fracture: a new method of assessment.

The value of colour flow Doppler ultrasound scanning in patients with suspected acute carpal scaphoid fracture has been examined. A prospective study of 78 patients with signs and symptoms of carpal scaphoid injury was undertaken over a period of 6 months. Both wrists of all patients were scanned within 12-72 h of injury. The radial artery and carpal scaphoid bone contours are visible using this type of imaging technique. The distance between the medial wall of the radial artery and the outer cortex of the scaphoid waist was measured. The scaphoid index is described and was calculated from this measurement. Patients were managed without knowledge of the ultrasound imaging result, using plain radiographs and clinical examination as the standard for determining the presence of a scaphoid fracture. All patients were followed to the resolution of symptoms. All 12 patients who were subsequently considered to have scaphoid fractures were identified using this imaging technique within 12-72 h after injury. We conclude that this imaging may be useful in the assessment of patients with carpal scaphoid fracture. It can be used early, as a supplementary investigation, in patients with suspected carpal scaphoid fracture in whom the initial plain radiographs are normal.

Adolescent↗
PubMed1993

Trauma in infants less than three months of age.

We evaluated the characteristics of traumatic injury and risk for subsequent trauma in infants less than three months of age (n = 111). Medical records were reviewed at presentation and one year later. Injury was due to abuse/neglect in 28%, whereas 72% were accidentally injured. Falls were the most common mechanism of accidental injury (67%). The percentage of infants with skull fractures was greater in the abuse/neglect group than in the accidental group (7/31 vs 7/80; P < 0.05) with a tendancy toward more diastatic and multiple skull fractures (6/7 vs 2/7) as well as intracranial hemorrhages (3/7 vs 0/7). More infants in the abuse/neglect group suffered extremity fractures (4/31 vs 2/80; P < 0.05). Hospitalization was more frequent (12/31 vs 8/80; P < 0.001), as was social or protective service intervention (25/31 vs 17/80; P < 0.001), in the abuse/neglect group. The two groups showed no difference in the number of previous emergency department (ED) visits; however, the use of the ED declined significantly in the abuse/neglect group following the trauma (0.81 +/- 1.2 vs 1.5 +/- 2.1 visits; P < 0.05). The abuse/neglect group tended to have a greater number of subsequent traumatic injuries than those accidentally injured. Abuse/neglect should be considered in any seriously injured infant less than three months of age because of the likelihood of subsequent trauma.

Accidental Falls↗
PubMed1993

The emerging need for a SIDS support group for family child care providers in Minnesota.

In Minnesota, 37% of all deaths due to Sudden Infant Death Syndrome (SIDS) in 1989 occurred in a family child care home. An ongoing monthly support group was developed for child care providers who experienced a SIDS-related death in their homes. This was developed in response to a desire to have a support group specifically for providers and separate from parent support groups. Evaluation by group participants indicated that such a group was effective in helping them work through the grief process.

Caregivers↗
PubMed1992

Antimutagenicity of secondary metabolites from higher plants.

Higher plants contain both mutagens and antimutagens and are susceptible to mutagenesis but screening programs for detection of antimutagenesis rarely employ higher plant systems. Short-term bacterial and mammalian tissue culture systems are the norm. Using modified screening tests for detecting antimutagenic agents, higher plants have been shown to contain a variety of structurally novel antimutagenic agents. Systematic bioassay-directed methodology resulted in the isolation in pure form and biological and chemical characterization of the responsible individual active components from various plants. The methodology in use is illustrated by the isolation of cinnamic acid, cinnamyl cinnamate and cinnamyl ricinoleate as the active constituents of the classic medicinal plant product, Styrax asiatica. The methods which may be used to reveal structure-activity relationships and to explore putative molecular modes of action are illustrated with excerpts from the same study.

Antimutagenic Agents↗
PubMed1992

Increasing generalized social interactions in psychotic and mentally retarded residents through peer-mediated therapy.

This study investigated whether withdrawn adults living in a residential center for psychotic and mentally handicapped persons could serve as peer therapists to increase the social interaction of other withdrawn residents. Two pairs of residents served as participants. Treatments were introduced and evaluated within a multiple baseline with reversal design. After baseline, the peer therapist was instructed to increase the social interactions of a target peer through engagement in social interactions. The results demonstrated that the peer therapist increased the social interactions of target peers. However, these increases did not generalize to other residents until the introduction of a multiple peer therapist condition. The percentage of time the peer therapists interacted with other nontarget residents also increased throughout the study. These results were maintained during a 4-month follow-up condition.

Adult↗
PubMed1991

Chlordecone (Kepone) on the night of proestrus inhibits female sexual behavior in CDF-344 rats.

The effect of the estrogen-like chlorinated pesticide chlordecone (Kepone) on sexual behavior was examined in proestrous rats following treatment with 25, 50, or 75 mg/kg chlordecone. In most animals, sexual behavior, both receptivity and proceptivity, was reduced within 60 min following the higher dosage of chlordecone. Reduced sexual receptivity occurred more slowly with 50 mg/kg chlordecone (usually within 180 min) and no reduction was seen following 25 mg/kg chlordecone. The reduced sexual behavior after chlordecone treatment preceded the onset of marked chlordecone-induced tremor. A group of rats treated with 75 mg/kg chlordecone was euthanized at the time that behavioral inhibition began to develop. The content of serotonin, norepinephrine, and their principal metabolites was determined by high-performance liquid chromatography of extracts of brain tissue of these animals. In hypothalamus, increases in serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) content, and a decrease in the level of norepinephrine (NE), were detected in chlordecone-treated rats relative to matched controls which received vehicle. The content of 5-HT was also increased in preoptic area of chlordecone-treated females. The content of the catecholamine metabolite, 3,4-dihydroxy-phenylacetic acid, was unaffected by chlordecone in either part of brain. These are the first observations of the parallel effects of chlordecone on receptive and proceptive behaviors, and on neurochemistry, in female rats; the results demonstrate short-latency effects of the pesticide treatment on the CNS events that mediate female reproductive behavior. Results of previous studies had led to the suggestion that chlordecone's inhibition of sexual behaviors resulted from its interaction with the intracellular estrogen receptor. However, the rapidity of the inhibition during the period of ongoing sexual behavior makes it unlikely that the inhibition is mediated by the pesticide's action at the intracellular estrogen receptor. Because of the importance of sexual behaviors to reproductive fitness, the current results indicate that nonsteroidal, behavioral mechanisms could contribute to chlordecone's neuroreproductive toxicity.

Analysis of Variance↗
PubMed1991

Inhibition by cocaine of excitation-contraction coupling in isolated cardiomyocytes.

The effects of cocaine on the Ca2+ fluxes responsible for excitation-contraction coupling were studied in isolated ventricular rat heart cells loaded with the fluorescent Ca2+ indicator fura-2. Ca2+ transients in response to electrical field stimulation were followed using a fluorescence ratio method in which excitation light was alternated with 5-ms resolution. The cardiomyocytes maintained a basal cytosolic Ca2+ concentration of approximately 70 nM, which increased to a peak of 450 nM in response to each electrical stimulus. The addition of cocaine (10 microM) to cells stimulated at 0.4 Hz decreased the magnitude of the electrically induced Ca2+ transients by 30 +/- 4% within 5 s. This inhibitory effect of cocaine was dose dependent, with a 50% reduction in the Ca2+ transient occurring at 40 microM cocaine. The effects of cocaine were not associated with any permanent cell damage and could be reversed by washing the cells free of the drug. Cytosolic Ca2+ increases in response to K(+)-induced depolarization of the cardiomyocytes were much less sensitive to cocaine than the electrically induced Ca2+ transients. In this respect the effects of cocaine were similar to the actions of lidocaine and tetrodotoxin but distinct from the effects of nitrendipine and verapamil. Cocaine had no effect on the caffeine-releasable Ca2+ pool in cardiomyocytes. These data demonstrate that cocaine directly inhibits the Ca2(+)-dependent steps of excitation-contraction coupling in heart muscle cells. Sarcolemmal Na+ channels represent a possible locus for this action of cocaine.

Animals↗
PubMed1990

The disulphide-bond content and rheological properties of intestinal mucins from normal subjects and patients with cystic fibrosis.

The disulphide/thiol (S-S/SH) content and rheological properties of highly purified small-intestinal mucins from normal (N) subjects and patients with cystic fibrosis (CF) were investigated. (1) An assay was developed to measure free SH groups (before reduction) and total SH content (after reduction) using 4,4'-dipyridyl disulphide. S-S bonds were calculated by difference. Experimental values for the S-S and SH contents of well-characterized proteins obtained with the assay showed good agreement with expected values. (2) The S-S and free SH contents of nine N and six CF mucins were variable: 44.4 +/- 5.4 nmol of S-S and 4.3 +/- 1.1 nmol of free SH per mg of N mucin and 31.7 +/- 7.6 nmol of S-S and 7.5 +/- 3.7 nmol of SH per mg of CF mucin. N and CF mucins were not statistically different. In most mucins, approximately 90% of the SH groups were involved in S-S bonds. (3) Gels were reconstituted from the same N and CF mucins at concentrations between 8 and 25 mg/ml and their rheological properties were assessed by using a magnetic microrheometer. (4) Once formed, mucin gels were stable and maintained the same mechanical properties over a long period of time (3-14 days). (5) The rheological profiles of both N and CF samples did not vary with the concentration of mucin present and were characteristic of weak, visco-elastic gels. (6) Although variations were seen in the visco-elastic properties of individual mucins, no systematic differences were detected between N and CF preparations. (7) There was no apparent correlation between the rheological properties of a mucin and its S-S/SH content.

Cysteine↗