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Biomedical subjects

M Carroll

Publications and source records attributed to M Carroll.

At least 127 records · Page 7Linked to original sources
PubMed1989

The prevalence of high blood cholesterol levels among adults in the United States.

Using the National Cholesterol Education Program's Guidelines for the Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults and the most recent nationally representative serum total cholesterol and lipoprotein data for adults (ages 20 to 74 years) from the second National Health and Nutrition Examination Survey (1976 to 1980), it is estimated that 41% of adults should have lipoprotein analysis after an initial measurement of serum total cholesterol. Furthermore, it is estimated that 88% of those who need lipoprotein analysis, or 36% of all adults aged 20 to 74 years, are candidates for medical advice and intervention for high blood cholesterol levels. We estimate, based on 1986 population data, that approximately 40 million Americans between the ages of 20 and 59 years are candidates for medical advice and intervention. An additional 24 million Americans aged 60 years and older are candidates. Overall, we estimate that about 60 million Americans aged 20 years and older are candidates for medical advice and intervention for high levels of blood cholesterol, although a less intensive approach might be appropriate for elderly patients.

Adult↗
PubMed1989

Sulfinpyrazone prolongs survival and decreases platelet uptake of heart allografts.

The purpose of this study was to evaluate the potential benefit of the platelet active drug sulfinpyrazone (SPZ) on uptake of indium-III-oxine (111In)-labeled platelets and survival of rat heart allografts. Lewis rats bearing ACI heterotopic heart transplants were treated with SPZ in high, intermediate, or low doses. In 111-labeled platelet uptake was measured 5 days postoperatively and calculated as a ratio between the transplanted and native hearts. Left and right ventricles were measured separately. SPZ given in doses of 400 and 200 mg/kg daily significantly decreased platelet uptake in the graft and reduced the ratio of uptake between transplanted and native hearts (P less than 0.05). In animals treated with SPZ 100 mg/kg/day platelet uptake was not significantly less than that of the nontreated control animals. Survival of allografts was determined by daily palpation and compared to vehicle-treated controls. Mean graft survival was prolonged for animals treated with 100 mg/kg and 200 mg/kg daily, i.e., 19.0 +/- 3.02 and 11.42 +/- 1.97 days, respectively. Animals administered 400 mg/kg did not have longer graft survival than controls (6.63 +/- 0.66 versus 6.31 +/- 0.18 days). Most animals in the 400 mg/kg group died as a result of adverse side effects of the drug. We conclude that SPZ in low to intermediate doses prolongs allografted heart survival. The enhanced survival in the lower dose group may in part be due to mechanisms other than platelet adhesiveness.

Animals↗
PubMed1989

Uptake of perfusion imaging agents by transplanted hearts: an experimental study in rats.

There is a need for a reliable noninvasive marker of rejection in transplanted hearts. Endomyocardial biopsy is now the universally accepted diagnostic method of choice, but the invasiveness of the procedure and the limited size of the sample obtained makes this method far from ideal. As coronary blood flow may be expected to decrease during acute rejection, there has been interest in thallium-201 chloride (T1), a perfusion marker, as an imaging agent for diagnosing cardiac rejection. Hexakis(t-butylisonitrile)-technetium (Tc-TBI) is a representative of a new class of radiopharmaceuticals proposed as perfusion markers. We have compared the uptake of these imaging agents in a rat model of cardiac transplantation. Uptake of Tc-TBI as well as of T1 was significantly lower in rejecting than in nonrejecting hearts. This change was found in both left (LV) and right (RV) ventricles. Allografts in animals treated with cyclosporine (CyA) showed less severe rejection and higher uptakes of both imaging agents as compared to unmodified rejection. Our results suggest that perfusion imaging with these radionuclides is a potentially useful approach to the problem of detecting allograft rejection.

Animals↗
PubMed1989

High density lipoprotein cholesterol levels among US adults by selected demographic and socioeconomic variables. The Second National Health and Nutrition Examination Survey 1976-1980.

The distribution of serum high density lipoprotein cholesterol (HDL cholesterol) levels was determined on a nationally representative sample of 9,625 adults aged 20-74 years, as part of the Second National Health and Nutrition Examination Survey, 1976-1980 (NHANES II). Mean HDL cholesterol levels were higher in women compared with men (an age-adjusted difference of 8.9 mg/dl for whites and 4.4 mg/dl for blacks). HDL cholesterol levels were higher in blacks compared with whites (an age-adjusted difference of 7.4 mg/dl for men and 2.8 mg/dl for women). All differences were statistically significant (p less than 0.01). These relations remained after stratification by age, income, poverty index, education, body mass index, alcohol consumption, cigarette smoking, and physical activity. For whites, HDL cholesterol levels were highest in the highest category of earnings, whereas blacks generally had lower levels of HDL cholesterol with increased earnings. In a multivariate model, important predictors of higher HDL cholesterol levels were being female, being black, and reporting a higher frequency of alcohol consumption. Less strongly related were age, years of education, and reported high physical activity. Smoking and body mass index were strongly negatively related to HDL cholesterol levels. The findings in this national study support previous findings in selected populations in the United States.

Adult↗
PubMed1989

Brain metastasis from nonseminomatous germ cell tumors of the testis: case report and review of the role of surgery.

The prognosis for patients with nonseminomatous germ cell tumor of the testis is good, even when extensive metastatic disease is present, because this tumor is very sensitive to chemotherapy with cisplatin, vinblastine, and bleomycin (PVB). If a metastasis occurs in the brain, however, the prognosis is poor because the blood-brain barrier limits the entrance of these drugs into the brain and creates a sanctuary for tumor. The current treatment for a brain metastasis is either standard PVB chemotherapy plus whole brain radiation therapy or a rigorous chemotheraputic regimen that penetrates the blood-brain barrier better than PVB. Surgery is seldom used for brain metastasis, largely because of the poor results with surgical debulking in noncentral nervous system disease. This is the report of a patient with disseminated nonseminomatous germ cell tumor and multiple large brain metastases, who was treated with surgery, PVB, and whole brain radiation therapy and cured. Evidence is presented to support a role for surgical debulking in patients with large brain metastasis.

Adolescent↗
PubMed1989

The extent of small fibre sensory neuropathy in diabetics with plantar foot ulceration.

Thresholds for cutaneous warming and cooling stimuli were measured in 20 diabetics with neuropathic foot ulcers. All patients had a profound disturbance of sensory perception in the ulcerated foot with complete loss of perception of warming; thresholds for vibration and cooling were highly abnormal in all but two patients. Measurements of thermal threshold were made on both feet in 10 patients: warming was lost bilaterally in all, and cooling was bilaterally absent in six. There was no clear pattern of sensory loss in those diabetics with unilateral foot ulceration to suggest that sensory impairment was the determining factor for the development of a plantar ulcer. Measurements of thermal thresholds were made at additional sites in 13 patients and although the most marked abnormalities of sensation were always found in the feet, in some severe neuropaths, abnormal thresholds on the hand and even the face were demonstrated. Thresholds for warming were invariably more abnormal than thresholds for cooling. The diabetics with neuropathic ulceration in this study all had severe generalised peripheral nerve disease involving large myelinated as well as both small myelinated and unmyelinated sensory fibres. The quantitative evidence on the distribution of sensory loss for thermal sensations supports the hypothesis that the neuropathic process affecting the small myelinated and unmyelinated fibres is length dependent.

Adult↗
PubMed1989

Learning artificial orthographies: further evidence of a nonanalytic acquisition procedure.

Previous research (Byrne, 1984) showed that adults who learned to read an orthography representing phonetic features (voicing, place of articulation) did not readily obtain usable knowledge of the mapping of phonetic features onto orthographic elements, as evidenced by failure to generalize to partially new stimuli. The present Experiment 1 used a different method of detecting learning savings during acquisition. Subjects learned a set of complex symbols standing for phones, with the elements representing voicing and place. In a second acquisition set, the signs for voicing were reversed. Learning speed was not affected, which was consistent with the claim that feature-element links went unnoticed in initial acquisition. In Experiment 2, some subjects were instructed to "find the rule" embodied in the orthography. None did, and acquisition rates were no different from those of uninstructed subjects. In Experiment 3, subjects had 4 h of training on the orthography, with consistent feature-symbol mapping for half of the subjects and arbitrary pairings for the remainder. No reaction time advantage emerged in the consistent condition, which is further evidence of nonanalytic acquisition. The results are related to data from children learning to read.

Cues↗
PubMed1989

Caricature: some considerations.

Familiarity with caricature illustration will help the medical illustrator look forward to these occasional projects. Tips and the author's experiences are related to help the first-time caricaturist.

Caricatures as Topic↗
PubMed1989

Uptake of myocardial imaging agents by rejecting and nonrejecting cardiac transplants. A comparative clinical study of thallium-201, technetium-99m, and gallium-67.

To study the scintigraphic detectability of cardiac rejection, we performed 135 planar myocardial scans ([99mTc]pyrophosphate, 85; 201Tl, 36; 67Ga, 14) together with endomyocardial biopsies in ten patients for a (mean) 17-mo postoperative period. Specificity of each agent exceeded 89%. Technetium-99m pyrophosphate showed results that significantly correlated with the severity of rejection (p = 0.03), as shown by biopsy, but neither 201Tl nor 67Ga did so (p = 0.63 and 0.81, respectively). Technetium-99m pyrophosphate showed better diagnostic accuracy (85%) than 201Tl (69%) and 67Ga (64%). Technetium-99m pyrophosphate also showed higher negative predictive value (91%) than thallium (76%) and gallium (69%). Thus, a normal 99mTc pyrophosphate scan was usually associated with absence of cardiac rejection. However, all three agents showed unacceptably poor sensitivity (0% to 30%) and thus were not useful as a screening test for cardiac rejection, even when the same agent was used serially in imaging a given patient.

Adult↗
PubMed1989

Illustrating for newspapers.

Medical illustrators wishing to pursue non-medical editorial projects will find newspaper illustration advantageous in building a diverse portfolio and increasing their client base.

Medical Illustration↗
PubMed1987

Glycoproteins of trypanosomes: their biosynthesis and biological significance.

1. Trypanosomes are unicellular parasites that cause human sleeping sickness in Africa and Chagas' disease in South America. Glycoproteins are important components of their plasma membrane. 2. The bloodstream form of the extracellular salivarian African trypanosome (e.g. Trypanosoma brucei) has the ability to express on its cell surface a repertoire of variant surface glycoproteins (VSGs) and in so doing, evades the immune response of the host (antigenic variation). 3. The VSG is probably synthesized initially in a manner like that of the membrane-bound glycoproteins of mammalian systems, but it also undergoes some novel post-translational modifications. 4. The stercorarian South American trypanosome (Trypanosoma cruzi) is an intracellular parasite which expresses different glycoproteins on its plasma membrane at various stages of its life-cycle, but does not exhibit antigenic variation. 5. The biosynthesis and functions of trypanosomal glycoproteins are compared with those of mammalian glycoproteins, and are discussed with particular reference to potential targets for chemotherapy and immunotherapy of trypanosomiasis.

Animals↗
PubMed1987

A monocyte function test (complement receptor enhancement) to assess the extent of bronchial carcinoma.

A monocyte function test (complement receptor enhancement) was undertaken on 45 patients with suspected bronchial carcinoma in whom this diagnosis was subsequently substantiated. In 38 (84%) complement receptor enhancement was below a range of values previously established for monocytes from 48 healthy control subjects and from 12 patients with non-malignant respiratory diseases. It was found that all 38 patients with reduced complement receptor enhancement had either local or widespread metastases, as determined by the chest radiograph and a variable combination of chest tomography, liver, bone and brain scanning, computed tomography, fibreoptic bronchoscopy, bone marrow aspiration, liver function tests, mediastinoscopy, and surgical assessment, where appropriate. By contrast, at the time of presentation there was no clear relationship between abnormal values in several conventional screening haematological or biochemical tests and the stage of the tumour. These results suggest that complement receptor enhancement might serve as a useful pointer to the extent of the disease, since low values were associated with extension within the chest and very low values were found with widespread metastases.

Adult↗
PubMed1986

Prospective evaluation of a watch policy in patients with inoperable non-small cell lung cancer.

The requirement for palliative chest radiotherapy in patients with non-small cell lung cancer (NSCLC) was assessed in a study of 134 inoperable patients not suitable for radical radiotherapy. Immediate chest radiotherapy was judged necessary in 86 (64%) because of significant symptoms from intrathoracic tumour or involvement of proximal airways. Forty-eight patients were monitored regularly without initial radiotherapy and of these, 26 (54%) required later chest irradiation because of progressive and significant symptoms due to intrathoracic disease. Median symptom-free survival in this group was 10 months. The requirement for immediate or delayed chest irradiation could not be predicted from either patient or tumour characteristics. The proportion of patients with NSCLC requiring palliative chest irradiation may have been overestimated from this study population; even so 22 of 134 patients (16%) did not at any stage in their illness require radiotherapy for chest symptoms.

Adult↗
PubMed1986

Lipid composition of bloodstream forms of Trypanosoma brucei brucei.

The qualitative and quantitative lipid composition of bloodstream forms of Trypanosoma brucei brucei S42 was compared with that of rat plasma and erythrocytes. The concentrations of lipid-bound phosphate and lipid-bound sialic acid in the trypanosomes were markedly higher than those of the rodent tissues. There was no trace in the trypanosomes of dolichol or dolichol phosphate. Trypanosomes contained two unidentified lipids: an acidic phospholipid and a highly polar glycolipid.

Animals↗