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Biomedical subjects

J M Robertson

Publications and source records attributed to J M Robertson.

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

The rudimentary first rib. A cause of thoracic outlet syndrome with arterial compromise.

The symptoms of thoracic outlet syndrome are neurologic, not vascular, in more than 95% of cases. Subclavian artery compression is usually related to cervical ribs; however, congenitally abnormal first ribs may also produce vascular compromise. We review our two cases of thoracic outlet syndrome associated with significant subclavian artery compression caused by rudimentary first ribs and the prior literature emphasizing the mechanism of injury, diagnostic features, and treatment. Transaxillary resection of the first and second ribs was curative in both cases. The operative specimens demonstrated fusion of the rudimentary first rib to the second rib, with compression of the subclavian artery by a large first-rib exostosis. Patients with thoracic outlet syndrome and a rudimentary first rib should be examined for substantial vascular compromise, and, if it is found, the abnormal first and second rib complex should be resected early without prolonged conservative measures.

Adult↗
PubMed1989

Detection of multiple cardiac papillary fibroelastomas using transesophageal echocardiography.

Papillary fibroelastomas are rare, benign cardiac tumors that may be associated with embolization, angina, and sudden death. We report a case of multiple papillary fibroelastomas diagnosed during life by transesophageal echocardiography. Surgical resection during mitral valve replacement for rheumatic mitral stenosis prevented the development of any of the life-threatening complications sometimes associated with this tumor.

Echocardiography↗
PubMed1989

Pleuropulmonary actinomycosis associated with a systemic-to-pulmonary artery fistula and contralateral metastatic back mass.

We report a case of systemic-to-pulmonary artery fistula associated with thoracic actinomycosis and with metastatic hematogenous dissemination to the soft tissues of the back. The difficulty in diagnosing thoracic actinomycosis may predispose to the increased incidence of hematogenous spread of this disease. Although resection of pulmonary tissue including the infectious mass was required in previous cases, resection of the pleural mass alone was curative in this patient when combined with penicillin therapy.

Abscess↗
PubMed1989

A monoclonal antibody to a 48 K antigen in oestrogen-dependent human breast cancer cells.

A mouse was immunised with an antigen(s) purified by oestradiol-Sepharose affinity chromatography of pooled oestrogen-receptor positive cytosols from human breast cancer tissue. One antibody secreting clone was identified which precipitated labelled antigen and which also stained MCF-7 cells. Culture supernatant and ascites fluid were used for immunofluorescence, SDS-PAGE-Western blotting, photoaffinity labelling and binding studies. The antibody staining of MCF-7 cells was inhibited by preincubation in oestrogen-receptor positive cytosol but was unaffected by oestrogen-receptor negative cytosol. MCF-7 cells stained whether cultured in the presence or absence of oestradiol. The oestrogen-receptor negative cell lines MDA-MB-231 and MDA-MB-330 did not stain. Binding studies with 16-alpha-iodooestradiol using breast cancer tissue cytosols followed by immunoprecipitation showed activity only with oestrogen-receptor positive cytosols with optimal binding activity at 4 degrees C, unaffected by molybdate, but reduced at 25 degrees C or in the presence of 0.4 M KCl. Binding studies with MCF-7, MDA-MB-231 and MDA-MB-330 cytosols and nuclear fractions only showed activity with the MCF-7 cytosol and MCF-7 particulate fractions. The antibody recognised a 48 K species in both MCF-7 cytosol and nuclear fractions but not in the cytosol and nuclear extracts of oestrogen-receptor negative cell lines. Photoaffinity labelling using 16 alpha-iodooestradiol suggests the 48 K antigen does not bind oestradiol directly. The relationship of this antigen to the classical oestrogen-receptor and receptor complex awaits further clarification.

Antibodies, Monoclonal↗
PubMed1989

A case-control study of circulatory, malignant, and respiratory morbidity in carbon black workers in the United States.

The exposures to total dust of a group of carbon black workers with selected circulatory, malignant, and respiratory diseases were compared with the exposures of nonaffected, matched control workers. Exposure was calculated by combining ambient air measurements (mg/m3) for each job category with the months workers had spent in each job. The cumulative total dust exposure levels of the cases were comparable to those of the controls, with the exception of men who had diseases of the circulatory system and who had experienced significantly less exposure than had the matched control workers. The results of this study indicate that exposure to carbon black in the workplace does not increase the workers' risks of circulatory, malignant, or respiratory morbidity.

Carbon↗
PubMed1989

The effect of domestic factors on respiratory symptoms and FEV1.

This study was conducted to determine whether indoor air pollution factors affected respiratory function and symptoms in 1357 non-smoking Caucasian children. Interviews were conducted to determine: exposure to pets and to gases, vapours and dusts from hobbies; the use of gas stoves; fireplaces, air conditioners and humidifiers; type of heating systems; and the number of residents, and the number of smokers in the home. The forced expiratory volume in one second (FEV1) was obtained from maximum expiratory flow volume curves, and symptoms from the application of a standardized questionnaire. Indoor pets and the use of fireplaces and humidifiers had no consistent relationships with FEV1 when considered individually or in combination with the other factors. Hobbies, the use of gas stoves, the absence of air conditioning, the use of hot water heating, crowded homes, and the presence of smokers in the home all had negative relationships with FEV1. The largest effect on lung function was observed in children from homes with hot water heating systems, whereas the smallest effect was observed in children with smokers in the home. Children who lived in homes with hot water heating systems with no air conditioning had mean FEV1 of up to 0.4 litres lower than did their counterparts who lived in homes with forced air heating and air conditioning. Pets, heating systems, cooking fuel, crowding and passive smoking showed no consistent effects on the reporting of any of the symptoms. Girls who were exposed to the emissions from indoor hobbies reported more phlegm, wheeze and dyspnoea.

Adolescent↗
PubMed1989

Vitamin E intake and risk of cataracts in humans.

Experimental evidence suggests that oxidative stress due to the accumulation of free radicals plays a role in the pathogenesis of cataracts and that the process can be prevented or ameliorated by antioxidants. In addition, a recent study found that cataract patients tended to have lower serum levels of vitamins C, E, or carotenoids than did control subjects. This investigation, which compared the self-reported consumption of supplementary vitamins by 175 cataract patients with that of 175 individually matched, cataract-free subjects, revealed that the latter group used significantly more supplementary vitamins C and E (p = 0.01 and 0.004, respectively). Inasmuch as the observed reduction in risk of cataracts was at least 50%, a randomized, controlled trial of vitamin supplementation in cataract prevention seems justified.

Aged↗
PubMed1989

Pott's disease. A resurgent challenge to the thoracic surgeon.

Nineteen patients were treated at the Los Angeles County Harbor/UCLA Medical Center between 1971 and 1986 for tuberculosis of the spine. Fourteen were immigrants, a high-risk group. A high index of suspicion is required for Pott's disease, which occurs in fewer than 1 percent of patients with tuberculosis, often presents with nonspecific symptoms, and may result in permanent deformity or neurologic impairment. CT scan, the most useful diagnostic test, showed abnormal results in 11 of 11 patients. MRI, a newer modality, may provide even more information. Eight patients required operation in addition to antimicrobial therapy. Four had lesions between T3 and T10, where the spinal canal is narrow, of whom three (75 percent had neurologic involvement. All four underwent anterior approach (thoracotomy) for decompression, debridement, and spinal fusion. Fifteen had lesions between T11 and S2. Three (20 percent) had neurologic involvement but responded to medical treatment alone. Four underwent drainage of abscess or spinal fusion for deformity. Combined surgical and medical treatment gave excellent results in this series.

Adolescent↗
PubMed1989

Predictive risk factors for periannular extension of native valve endocarditis. Clinical and echocardiographic analyses.

The study objective is to identify clinical, microbiologic, and/or echocardiographic risk factors present early in the course of native valve endocarditis that predict subsequent development of periannular extension of infection. A multivariate computer-generated analysis of 21 clinical-microbiologic parameters and 11 two-dimensional echocardiographic parameters in patients with native valve endocarditis was designed. These parameters were statistically compared in operated-on patients with native valve endocarditis with and without periannular extension of infection. The study took place in a 600-bed acute-care, nonreferral, municipal hospital primarily servicing an indigent patient population. Seventy-three documented episodes of native valve endocarditis occurred between the years of 1973 and 1987, including 29 operated-on patients with surgically confirmed periannular extension of infection and 44 operated-on patients without periannular extension of infection. Multivariate logistic-regression analyses of multiple clinical, microbiologic, and echocardiographic parameters which are potentially predictive of eventual periannular extension of native valve endocarditis were carried out. The only two independent parameters that significantly predicted periannular infection among patients with native valve endocarditis were (1) aortic valve involvement and (2) abuse of intravenous (IV) drugs (p less than 0.01; p less than 0.01, respectively, multivariate analysis). The relative risk of developing periannular extension of endocarditis among patients with aortic valve involvement and/or IV drug abuse was increased by approximately 2.5-fold compared with patients without these characteristics. Factors not significantly associated with increased risk of periannular extension of native valve endocarditis included the following: prolonged febrile morbidity; Staphylococcus aureus etiology; or two-dimensional echocardiographic demonstration of vegetations, large vegetations (greater than or equal to 1 cm), multiple vegetations, or enlargement of aortic root or annulus. These data suggest that patients with native aortic valve endocarditis, particularly in the setting of IV drug abuse, should be considered for routine, serial noninvasive evaluation for the early detection of periannular extension of their infection.

Adult↗
PubMed1989

Simultaneous technetium-99m MIBI angiography and myocardial perfusion imaging.

Resting first-pass radionuclide angiography (FPRNA) was performed with the myocardial perfusion agent technetium-99m MIBI. In 27 patients, it was compared with technetium-99m diethylenetriamine pentaacetic acid FPRNA. A significant correlation was present in left (r = 0.93, p less than 0.001) as well as right (r = 0.92, p less than 0.001) ventricular ejection fraction measured with both radiopharmaceuticals. In 13 patients, MIBI derived segmental wall motion was compared with contrast ventriculography. A high correlation was present (p less than 0.001), and qualitative agreement was found in 38/52 segments. In 19 patients with myocardial infarction a significant correlation was present between MIBI segmental wall motion and perfusion scores (p less than 0.001). In ten patients with a history of myocardial infarction, 18 myocardial segments demonstrated diseased coronary vessels and impaired wall motion at contrast angiography. These segments were all identified by the MIBI wall motion and perfusion study. We conclude that MIBI is a promising agent for simultaneous evaluation of cardiac function and myocardial perfusion at rest.

Angiography↗
PubMed1989

Myocardial contusion in the stable patient: what level of care is appropriate?

To evaluate the significance of myocardial contusion, we evaluated 243 stable patients hospitalized for blunt chest trauma between 1982 and 1986. The groups were identified according to results of radionuclide angiography, mean injury severity score (ISS), and outcome. Group I (n = 71; mean ISS = 12.7) patients were those without myocardial contusion by radionuclide angiography. Two patients with cardiac complications were in this group. The patients with myocardial contusion were divided into two groups. Group II (n = 69; ISS = 19.5) patients had myocardial contusion as an isolated injury, and group III (n = 103; ISS = 30.9) patients had myocardial contusion and injury to at least one other organ system. Three patients from group II had cardiac complications. Eleven patients from group III had cardiac complications. There were no significant differences between the cardiac complication rate in the three groups, and each complication was present when the patient arrived in the emergency department. The predicted mortality rate based on ISS was 10% to 20% for patients with myocardial contusion, whereas the observed mortality rate for the groups (II and III) overall was 0.58%. We conclude that in the stable trauma patient myocardial contusion (1) does not by itself increase the risk of complication, (2) does not necessitate intensive care unit monitoring, (3) should be devalued when computing ISS scores, (4) may account for lengthy and often unnecessary hospitalization, and (5) in patients at risk for complications may be identified by ECG abnormalities on arrival to the emergency department.

Adolescent↗
PubMed1988

Familial and sporadic breast cancer cases in Iceland: a comparison related to ABO blood groups and risk of bilateral breast cancer.

This study was aimed at determining whether the familial clustering often observed in breast cancer is associated with genetic factors. We compared familial and sporadic breast cancer cases with respect to ABO blood group distribution and the risk of bilateral disease, using the data from the Icelandic Cancer Registry which contains genealogical information for about 30% of the breast cancer cases diagnosed in Iceland since 1911. Cases were classified as familial if at least one first-degree relative had breast cancer. Using this criterion, we identified 184 familial cases and 572 sporadic cases. The familial cases had a 2-fold higher prevalence of blood group B than did the sporadic cases, and the frequency of this blood group in non-affected relatives of cases was significantly reduced. Familial cases were about 2.7 times more likely to suffer from bilateral breast cancer than were the sporadic patients. These results support the presence of a genetic factor in the etiology of familial breast cancer.

ABO Blood-Group System↗
PubMed1988

Interaction of elongation factors EF-G and EF-Tu with a conserved loop in 23S RNA.

The elongation factors EF-Tu and EF-G interact with ribosomes during protein synthesis: EF-Tu presents incoming aminoacyl transfer RNA to the programmed ribosome as an EF-Tu-GTP-tRNA ternary complex and EF-G promotes translocation of peptidyl-tRNA and its associated messenger RNA from the A to the P site after peptidyl transfer. Both events are accompanied by ribosome-dependent GTP hydrolysis. Here we use chemical probes to investigate the possible interaction of these factors with ribosomal RNA in E. coli ribosomes. We observe EF-G-dependent footprints in vitro and in vivo around position 1,067 in domain II of 23S rRNA, and in the loop around position 2,660 in domain VI.EF-Tu gives an overlapping footprint in vitro at positions 2,655 and 2,661, but shows no effect at position 1,067. The 1,067 region is the site of interaction of the antibiotic thiostrepton, which prevents formation of the EF-G-GTP-ribosome complex and is a site for interaction with the GTPase-related protein L11 (ref. 3). The universally conserved loop in the 2,660 region is the site of attack by the RNA-directed cytotoxins alpha-sarcin and ricin, whose effects abolish translation and include the loss of elongation factor-dependent functions in eukaryotic ribosomes.

Escherichia coli↗
PubMed1988

A cross-sectional study of pulmonary function in carbon black workers in the United States.

Since a proportion of airborne carbon black particles is of respirable size, the possibility that it may affect pulmonary function was investigated in 913 employees of 6 carbon black producers in the United States. Exposure was estimated by combining the mean total dust exposures of each job category with the length of time workers had spent in each job, giving a measurement expressed in mg/m3.months. Pulmonary function was measured by spirometry. The major variables affecting pulmonary function were age and cigarette smoking. When the effects of age and smoking were controlled in an age-specific, two-way analysis of variance, no consistent effects of total dust exposure were detectable in these workers. This study provided no evidence that exposure to total dust under the conditions pertaining in the contemporary carbon black industry had detrimental effects on the pulmonary function of men employed in the production and handling of this product.

Adult↗