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Biomedical subjects

B Meier

Publications and source records attributed to B Meier.

At least 469 records · Page 26Linked to original sources
PubMed1983

Percutaneous transluminal coronary angioplasty in patients with prior coronary bypass surgery.

To improve symptomatic status and avoid reoperation, 122 initial and 7 repeat percutaneous transluminal coronary angioplasty procedures were performed in 116 patients with disabling angina pectoris at a mean of 26.8 months (range 2 to 132) after coronary bypass surgery. Marked angiographic improvement (greater than 30% reduction in diameter stenosis) was obtained in 107 (88%) of the 122 initial procedures and in all 7 repetitions. Mean stenosis was reduced from 78 +/- 13% (mean +/- standard deviation) to 25 +/- 13% (p less than 0.0001) and mean pressure gradient from 49 +/- 15 to 11 +/- 8 mm Hg (p less than 0.0001). Complications were: emergency surgery (three patients), Q wave infarction (one patient), myocardial infarction by enzyme criteria only (four patients) and non-occluding coronary dissection (one patient). There were no neurologic or peripheral vascular complications and no early deaths. One late death occurred 14 months after an unsuccessful but uncomplicated angioplasty procedure. At a mean follow-up of 8.3 months, 88 patients (76%) were free of angina or in improved condition. In patients followed up for at least 6 months, evidence of restenosis occurred in 9 (53%) of 17 saphenous veins, 1 (50%) of 2 proximal graft anastomoses, 4 (18%) of 22 distal graft anastomoses and 5 (14%) of 37 native coronary arteries. When coronary anatomy is suitable, percutaneous transluminal angioplasty is an attractive alternative to reoperation in symptomatic patients with prior coronary bypass surgery.

Adult↗
PubMed1983

Does length or eccentricity of coronary stenoses influence the outcome of transluminal dilatation?

In 526 patients undergoing a first percutaneous transluminal coronary angioplasty (PTCA) of a single native vessel, we studied the influence of length and eccentricity of the lesion on complications and primary success. Long stenoses (greater than or equal to 5 mm, n = 153) did not differ from short stenoses (less than or equal to 4 mm, n = 265) in terms of overall complications or gain in lumen diameter and distal pressure. Eccentric stenoses (n = 155) showed a lower rate of primary success than concentric stenoses (n = 338) (80% vs 89%, p less than 0.05). Inability to cross the stenosis was the main reason for failure. Stenoses that were long and eccentric (n = 51) had the highest incidence of complications (24%) and stenoses that were short and concentric (n = 177) the lowest (12%, p less than 0.05). However, the average outcome expressed by gain in lumen diameter and distal pressure was equal in both groups and is obviously more dependent on technical factors than on anatomy. Nevertheless, length and, particularly, eccentricity of a lesion constitute risk factors for PTCA. They may be overcome by technical skill and sophisticated equipment, such as steerable catheters.

Adult↗
PubMed1983

Should coronary arteries with less than 60% diameter stenosis be treated by angioplasty?

We evaluated all patients receiving percutaneous transluminal coronary angioplasty (PTCA) in the past year for mild stenosis (60% or less diameter narrowing, n = 64, group 1) and compared them with a random sample of 330 patients with greater than 60% stenosis (n = 66, group 2) treated during the same year. The degree of coronary stenosis before PTCA was 52 +/- 7% (mean +/- SD) in group 1 and 79 +/- 11% in group 2. The primary success rate was 90% (58 of 64 patients) in group 1 vs 86% (57 of 66 patients) in group 2. The incidence of complications requiring coronary surgery after PTCA failed was similar in both groups (3 of 64 in group 1, 4 of 66 in group 2), but there were four occurrences of myocardial infarction in group 1 and none in group 2 (p less than .05). Recurrence of stenosis was judged on the basis of objective data, 76% of which were angiographic data, in 97% of the patients with primary success. At a mean interval of 5 months with a mean follow-up period of 7 months, 17 of 58 patients (29%) with primary success in group 1 and 24 of 57 patients (42%) in group 2 developed restenosis. In group 1, restenosis was markedly more severe (73 +/- 15%) than initial stenosis (p less than .005), which was not the case in group 2. In conclusion, PTCA in mild stenosis has favorable primary and long-term results, yet carries the risk of myocardial infarction and emergency operation and may, in some cases, even accelerate the disease process.

Adult↗
PubMed1983

Acute occlusion after percutaneous transluminal coronary angioplasty--a new approach.

Between July 1980 and November 1982, there were 935 coronary angioplasties attempted at Emory University Hospital. Of these patients, 20 developed acute occlusion. Of these 20, 19 presented within 3 hr of surgery or within 3 hr after stopping a continuous heparin infusion. Five patients required emergency surgery, but in 15 nitrates, nifedipine, and/or repeat angioplasty reopened the artery and the patient could be stabilized on continuous infusions of heparin and nitroglycerin. In only one case was an occluding thrombus evident on angiographic examination. The mechanism of acute occlusion is unknown, but coronary artery spasm may play a role.

Acute Disease↗
PubMed1983

Long-term exercise performance after percutaneous transluminal coronary angioplasty and coronary artery bypass grafting.

In our first 169 consecutive patients admitted to undergo percutaneous transluminal coronary angioplasty (PTCA) serial bicycle ergometric exercise sessions were scheduled to assess long-term-exercise performance. In 160 of these 169 patients (95%) an average of seven ergometric measurements were available during a mean follow-up period of 29 months (range 1 to 60 months). Two groups were formed. One consisted of 132 patients in whom PTCA was successful and the other consisted of 28 patients with failure of PTCA who subsequently underwent coronary artery bypass grafting (CABG) either on an emergency basis (12 patients) or as an elective procedure (16 patients). Exercise performance was expressed as work capacity in watts according to the highest completed exercise stage. In the successful PTCA group the actual work capacities increased from 74 +/- 42 W (mean +/- SD) before PTCA to 122 +/- 47 W at the most recent follow-up examination. In patients who underwent emergency or elective CABG the respective figures were 73 +/- 34 or 65 +/- 37 W before surgery and 120 +/- 41 or 119 +/- 41 W at the most recent follow-up examination (p less than .005 for all preprocedure to postprocedure comparisons). Successful PTCA and CABG after failed PTCA improve work capacity significantly. Comparison of our results with those of surgical studies indicates that a failed attempt at PTCA before CABG does not compromise the functional outcome of the operation, regardless whether it is done on an emergency or on an elective basis.

Angioplasty, Balloon↗
PubMed1983

Eosinophilic granuloma of the skeleton with involvement of the lung: a report of three cases.

Three adult patients with chronic bilateral pulmonary infiltrates due to eosinophilic granuloma are described. The diagnosis was based on histologically proven antecedent or concomitant osseous eosinophilic granuloma in all cases. Electron microscopy was performed in two cases, showing abundant Lx-bodies in both. Pulmonary tissue was obtained in the same two cases, yielding eosinophilic granulomas in one and non-specific septal infiltrates in the other. In the third case the assumption of pulmonary eosinophilic granuloma was made by clinical analogy, thus, avoiding lung biopsy. The course was characterized by lasting benefit from skeletal surgery in all patients and by refractoriness of pulmonary lesions to immunodepressants given to two patients. Progression of pulmonary disease was minimal or none during the observation period of four, three, and three years, respectively. Diffuse pulmonary infiltrates may be a manifestation of a covert osseous eosinophilic granuloma. Skeletal screening by x-ray or scintigraphy should be part of the work-up of otherwise unexplained diffuse lung lesions. It may obviate the need for lung biopsy.

Adult↗
PubMed1982

Synthesis of either Fe- or Mn-superoxide dismutase with an apparently identical protein moiety by an anaerobic bacterium dependent on the metal supplied.

Superoxide dismutase of Propionibacterium shermanii, an anaerobic that produces an iron superoxide dismutase, was purified from cells grown in iron-free conditions. The enzyme isolated was found to contain manganese and to have spectral and catalytic properties very similar to those of typical Mn-superoxide dismutases. Its electrophoretic mobility, molecular weight, and subunit size were identical with those of the Fe-enzyme. Amino acid compositions were practically indistinguishable in either case. The NH2-terminal sequence was found to be identical. The catalytic activity of an apoprotein sample prepared from the purified holoenzyme was restored by adding either Mn(II) or Fe(II). Only the metal/protein ratio varied from approximately 1 per subunit in the case of the Fe-enzyme to approximately 2 for the Mn-enzyme. It is concluded that this bacterium can accommodate either Fe or Mn on identical, or very slightly dissimilar, proteins forming active sites with the properties found in specific metallodismutases.

Amino Acids↗
PubMed1982

Induction or elimination of tumor-specific immunity against a chemically-induced rat tumor using auto-anti-idiotypic immunity.

DA rat sarcoma P1 and P2 were induced by dimethylbenz(a)anthracene. A tumor-specific immune response of DA rats against P1-tumor cells could be demonstrated at the humoral and cellular level. DA anti-P1 antibodies were purified on fixed P1-tumor cells and used as auto-immunogen in DA rats for the production of anti-idiotypic antibodies. Such anti-idiotypic antibodies could be demonstrated by using a solid-phase radioimmunoassay and by their ability to induce secondary type of DA anti-P1 response in vitro. In addition, such antibodies were able to induce cytotoxic T lymphocytes capable of eliminating P1-tumor cells but not control tumor cells. In some of the auto-immunized DA rats enhanced P1-tumor growth could be observed, indicating that the anti-idiotypic immune response had led to a selective ablation of idiotypic, potential anti-P1 reactive T cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

[Lactobacillus casei endocarditis after aortic valve prosthesis].

A report is presented on a 53-year-old patient with endocarditis caused by Lactobacillus casei 9 years after prosthetic replacement of the aortic valve with a Björk-Shiley graft. In spite of a delay of about 6 weeks before therapy was started (due to difficulties in identifying the causative agent), treatment with a combination of penicillin G and gentamicin was effective and replacement of the artificial valve was not necessary. Seven months after cessation of therapy the patient is still free of symptoms. No other report of conservatively managed endocarditis due to lactobacilli and involving a prosthetic valve was found in the literature accessible to our group.

Anticoagulants↗
PubMed1979

Nature of T-cell macrophage interaction in helper-cell induction in vitro. II. Two stages of T-helper-cell differentiation analyzed in irradiation and allophenic chimeras.

The genetic restriction in the T-cell-macrophage-like cell interaction in helper cell induction was investigated with allophenic and irradiation chimeras of various types. Using T cells from P leads to F1 chimeras, there was a restriction of cooperation with the parental haplotype accessory cells, unless the chimeric mice were repopulated with macrophages of the opposite haplotype before priming. T cells from primed or unprimed F1 leads to P chimeras only cooperated with recipient type accessory cells. These observations led to the hypothesis that there are two stages in the genesis of immunocompetence of T helper cells, one dependent on the thymus, and the other on peripheral macrophage-like cells. Purified T cells from P1 + P2 leads to F1 irradiation chimeras behaved in an unexpected manner in the unprimed state, preferring to cooperate with their own haplotype macrophages. This self preference was lost after antigen priming in vivo and was not noted in allophenic chimeras. This loss of self preference was restricted to the haplotypes represented in the chimeras, and did not extend to third party haplotypes. While these in vitro induced helper cells from chimeric mice show clear genetic restrictions at the T-cell macrophage-like cell interaction, there was no evidence for a matching T-B genetic restriction.

Animals↗
PubMed1979

Is genetically related macrophage factor (GRF) a soluble immune response (Ir) gene product?

The possibility that the antigen-presenting "macrophages" interacting with helper cells either directly or via the intermediary action of a soluble factor consisting of Ia antigen and a fragment of immunogen, termed GRG (genetically related factor), are a site of Ir gene action was investigated by using the synthetic polypeptide antigen (T,G)-A--L. It was found that T cells from (responder x nonresponder) F1 mice were stimulated by responder "macrophages" or GRF derived from these cells but not by the nonresponder macrophages of GRF from these cells. This suggests that the defect in helper cell induction in nonresponders is at the level of the presenting cell and that the macrophage factor GRF is a soluble Ir gene product. This conclusion was supported by the observation that there was normal presenting cell and GRF function in nonresponders, mouse strains such as CBA that yield helper cells and helper factor with (T,G)-A--L and have defects elsehwere.

Animals↗
PubMed1978

Percutaneous transluminal dilatation: a new treatment of renovascular hypertension?

Percutaneous transluminal dilatation of a left sided renal artery stenosis was performed in a 61 year old patient with hypertension. Biochemical and hemodynamic activity of the renal artery stenosis was demonstrated by measurement of renal venous renin-activity and determination of renal plasma flow and of pre- and poststenotic blood pressure values. Shortly after the dilatation procedure hypertension disappeared and renal plasma flow increased. The described procedure might be an alternative method to renal vascular surgery.

Arterial Occlusive Diseases↗