A surgical template for aligned placement of the osseointegrated implant.
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Acrylic Resins↗
Biomedical subjects
C M Johnson
Publications and source records attributed to C M Johnson.
Percutaneous placement of the Greenfield vena caval filter.
During the period from August 1986 to August 1987, 50 patients underwent percutaneous placement of a Greenfield vena caval filter from the right femoral vein, left femoral vein, or right internal jugular vein at our institution. All 50 patients had a contraindication to anticoagulation therapy or had complications of anticoagulation for deep venous thrombosis or pulmonary emboli. The percutaneous placement was accomplished in the angiographic suite with use of local anesthesia and was well tolerated by all patients. Only three complications related to the percutaneous approach occurred during the short-term follow-up (3 months to 1 year). These complications were deep venous thrombosis of the leg in two patients and misplacement of the filter in one patient. The three patients tolerated these complications well. We conclude that placement of Greenfield vena caval filters can be readily accomplished by means of percutaneous entry. Our experience demonstrated minimal associated morbidity and no mortality.
Aged↗
Successful treatment of pulmonary embolism and associated mobile right atrial thrombus with use of a central thrombolytic infusion.
Patients with pulmonary embolism and two-dimensional echocardiographic evidence of right atrial thrombus have a high mortality rate despite standard anticoagulation therapy. We used a direct central infusion of streptokinase in three such patients, who subsequently had rapid and complete clinical improvement. In this setting, thrombolytic therapy should be considered an effective therapeutic option.
Adult↗
The large flap sculptured facelift.
The large flap sculptured facelift is a redraping rather than a pinching or pulling operation. The skin flaps are redraped over the tightened, sculptured underlying fat-musculoaponeurosis. This procedure can be performed on a majority of patients with minimal complications.
Dermatologic Surgical Procedures↗
Platelet adherence to cardiac and noncardiac endothelial cells in culture: lack of a prostacyclin effect.
Cardiac tissues show a propensity to develop nonbacterial thrombotic endocarditis, a meshwork of platelets and fibrin. This lesion may cause a predisposition to subsequent colonization by circulating microorganisms, leading to infective endocarditis. We measured platelet adherence in vitro to cultured endothelial cells derived from the porcine aortic valve and ascending aorta. We found that valvular endothelial cells showed a twofold to threefold higher adherence than ascending aortic endothelial cells of chromium 51-labeled platelets in the presence of proteolytically active thrombin. This finding did not correlate with endothelial prostacyclin release: cardiac valve endothelial cells released more prostacyclin than did, ascending aortic cells, exogenous prostacyclin had no effect on thrombin-stimulated adherence, and aspirin inhibition of endothelial prostacyclin synthesis showed no effect on platelet adherence. Fixation of platelets abolished thrombin-stimulated adherence; fixation of endothelial cells had minimal effect. We suggest that these differences may contribute to the propensity of the cardiac valve to develop nonbacterial thrombotic endocarditis.
Aspirin↗
Acquisition, development, and treatment of Panamanian cutaneous leishmaniasis: a case history.
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Administration, Topical↗
Specific binding of Staphylococcus aureus to cultured porcine cardiac valvular endothelial cells.
Infective endocarditis usually occurs in patients who have had previous cardiac damage or who have congenitally abnormal hearts. However, this infection may afflict otherwise normal individuals, and it is often caused by Staphylococcus aureus. In these individuals, interactions between circulating microorganisms and resident cardiac endothelial cells may initiate the infection. In the present studies we established an assay to measure in vitro binding of S. aureus to porcine cardiac valve endothelial cells. We found that this interaction was specific and saturable with respect to time. In contrast, there was no specific binding of Escherichia coli, an organism that rarely causes endocarditis. Exogenous fibronectin had no effect on specific binding of S. aureus, and heat-killed organisms adhered equally well as viable bacteria. Fixation of the endothelial cells with formalin abolished all specific binding. Soluble components from bacterial extracts inhibited S. aureus binding in dose-dependent fashion. These observations suggest that circulating S. aureus may interact with specific sites on cardiac endothelial cells, thereby potentially initiating infective endocarditis.
Animals↗
Reducing nocturnal awakening and crying episodes in infants and young children: a comparison between scheduled awakenings and systematic ignoring.
Infants and toddlers (N = 33) exhibiting spontaneous awakening and crying episodes during the night were randomly assigned to one of three groups: scheduled awakenings, systematic ignoring or control. Scheduled awakenings consisted of a parent arousing and feeding or consoling the child 15 to 60 minutes before typical spontaneous awakenings. Once spontaneous awakenings were precluded, scheduled awakenings by parents were gradually eliminated. Systematic ignoring consisted of allowing the child to "cry it out" without parental attention except to ensure physical well-being of their child. Children in the scheduled awakening group and the systematic ignoring group awoke and cried less frequently than children in the control group during 8 weeks of treatment and during two follow-up checks, 3 and 6 weeks after treatment. Systematic ignoring was found to be more effective than the scheduled awakenings condition during 1 week of treatment; otherwise effects of the two conditions were similar. Implications of the use of these treatment procedures are discussed.
Child, Preschool↗
[Cutaneous leishmaniasis caused by Leishmania mexicana amazonensis in Panama].
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Adult↗
Denaturation and renaturation of the monomeric phosphoglycerate mutase from Schizosaccharomyces pombe.
The denaturation by guanidinium chloride of the monomeric phosphoglycerate mutase from Schizosaccharomyces pombe was studied. The loss in activity broadly parallels the changes in protein structure detected by fluorescence and c.d. Renaturation can be brought about by dilution of the denaturing agent. These processes were compared with those in the enzymes from baker's yeast and rabbit muscle, which are tetrameric and dimeric respectively. The effects of the cofactor 2,3-bisphosphoglycerate on the structure and stability of the S. pombe enzyme were also investigated.
Circular Dichroism↗
Rotational delivery with Kielland's forceps.
A retrospective study over 15 months showed that 10.7% of primigravid women and 1.6% of multigravid women were delivered by Kielland's forceps: a total of 145 babies. The successful vaginal delivery rate for attempted Kielland's forceps was 96.7%. The neonatal outcome was good and there were no perinatal deaths. Traumatic injuries were present in 7.6% of babies and were minor. The data show that even in the presence of fetal distress, Kielland's forceps can be safely employed for rotational delivery from the mid-pelvic cavity. This approach can avoid some caesarean sections without undue risk to the baby, the caesarean rate being 9.5%. As 10.7% of primigravid women required rotational delivery with Kielland's forceps, it is desirable that primigravid women should be cared for by obstetricians who are skilled in the use of the instrument, in order to maintain a low caesarean section rate in this group, with a good neonatal outcome.
Adult↗
In vivo glucose metabolism in the awake rat: tracer and insulin clamp studies.
The goals of this study were twofold: (1) to determine the in vivo dose-response relationship in the conscious, unstressed rat between the plasma insulin concentration and total body glucose uptake, and between plasma insulin and suppression of endogenous glucose production; and (2) to develop a physiologic compartmental model to describe the kinetics of plasma glucose in the rat in the basal state. In order to perform repeat insulin clamp studies in the same rat, chronic catheters were implanted in the aortic arch (via the carotid artery) and in the cardiac atrium (via the jugular vein), exteriorized, and fixed to the back of the skull with a dental cement cap. Insulin was infused at rates of 1.2, 2.4, 4.8, 12, and 24 mU/min.kg, and the plasma glucose was held constant at the basal level by a variable glucose infusion (euglycemic insulin clamp). The resulting steady-state plasma insulin concentrations ranged from 40 to 1,300 microU/mL. The dose-response curve for glucose uptake was sigmoidal in shape: in the basal state, total glucose utilization averaged 6.8 mg/min.kg at an insulin concentration of 9 microU/mL, half-maximal glucose uptake (18.3 mg/kg.min) occurred at a plasma insulin concentration between 70 and 80 microU/mL, and maximal uptake (36.6 mg/kg.min) was seen at an insulin level in excess of 100 microU/mL. Residual endogenous glucose production was evaluated by a prime-continuous infusion of (3-3H)-glucose. The dose-response curve for suppression of endogenous glucose output also was sigmoidal.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Porcine cardiac valvular subendothelial cells in culture: cell isolation and growth characteristics.
We established culture lines derived from the subendothelial region of the porcine aortic valve. These cells were isolated by extensive collagenase digestion of valvular tissue and were serially propagated with stable morphology. In sparse culture, valve subendothelial cells resembled skin fibroblasts. When confluent, the valve subendothelial cells formed ridges and piles similar to vascular smooth muscle cells. Endogenous in vitro labeling experiments using 35S-methionine showed that valve subendothelial cells synthesized and released several proteins not observed in parallel experiments using porcine skin fibroblasts and smooth muscle cells. Mitogen assays using media conditioned by porcine aortic valvular endothelial cells showed that the valve subendothelial cells, when compared to skin fibroblasts and smooth muscle cells, were particularly avid responders to the growth factors released by valve endothelial cells in vitro. The valve subendothelial cells also released 10-fold more prostacyclin in response to arachidonate than did skin fibroblasts or smooth muscle cells. We conclude that valve subendothelial cells show features that distinguish them from other cultured mesenchymal cells, and that this culture system will be useful for studies of the cellular basis of valvular heart disease.
Animals↗
Drapanas shunt using a spiral saphenous vein graft.
An alternative technique for creation of a Drapanas shunt was used in a 12-year-old boy with upper gastrointestinal bleeding. Dissatisfaction with available prosthetic grafts and the inherent limitations of other autogenous materials led to the use of a spiral saphenous vein graft to bridge the superior mesenteric vein and the inferior vena cava. Patency of the graft was demonstrated 1 year postoperatively, and the patient has not had further bleeding episodes for 2 years postoperatively. Continued use of this operation is necessary to determine its usefulness.
Gastrointestinal Hemorrhage↗
Percutaneous transluminal angioplasty in the lower extremities: a 5-year experience.
From January 1979 to March 1984, percutaneous transluminal angioplasty (PTA) was used to treat 148 limbs of 135 Mayo Clinic patients with occlusive arterial disease of the lower extremities. The procedure was technically successful in more than 95% of the attempts. The outcome was clinical improvement in 89 limbs and no improvement in 40 limbs; in 19 limbs, PTA was technically successful but the patient was dismissed from the hospital and lost to follow-up before the extent of improvement could be determined. Mean ankle/brachial pressure indices increased after PTA in those with clinical improvement but not in those without improvement. Clinical improvement was less likely to follow PTA in patients with advanced age, diabetes, severe initial symptoms, low ankle/brachial indices, or distal occlusive disease. In patients with improvement after PTA, the mean follow-up period was 33 months; during that time, failure (defined as recurrence of the original symptoms or the need for repeat PTA or operation) occurred at a rate of 6.4% per year. Serious complications occurred after three procedures (2.0%). We conclude that PTA is technically feasible and generally safe for many patients with occlusive arterial disease of the lower limbs.
Aged↗
Antibiotic therapy for severe infections in infants and children.
In infants and children, drug absorption, distribution, metabolism, and excretion may differ considerably from these factors in adults; thus, differences also exist in therapeutic efficacy and toxicity of various antibiotics. Because of known toxicity, certain drugs--such as chloramphenicol in high doses, the sulfonamides, and tetracycline--should not be used in neonates. Antibiotic therapy should be modified in neonates because of biologic immaturity of organs important for the termination of drug action. Because of poor conjugation, inactivation, or excretion, the serum concentrations of many antibiotics may be higher and more prolonged in neonates than in older infants. Thus, the dosages of many antibiotics must be lower and the intervals between administration must be longer. The appearance of strains of ampicillin-resistant Haemophilus influenzae, the slow development of resistance to chloramphenicol among gram-negative and gram-positive bacteria, and the development of improved analytic methods to measure chloramphenicol have all resulted in the use of this drug in select cases of serious infection in children beyond the neonatal age. Third-generation cephalosporins have an important role in empiric treatment of pediatric bacterial meningitis because of their ability to penetrate the central nervous system and their effectiveness against ampicillin- or chloramphenicol-resistant Haemophilus strains and against many gram-negative bacteria in the Enterobacteriaceae group.
Anti-Bacterial Agents↗
Effects of cefonicid and other cephalosporin antibiotics on male sexual development in rats.
The purpose of this study was to determine whether cefonicid, a cephalosporin antibiotic with a modified N-methylthiotetrazole (MTT) side chain, caused testicular toxicity when subcutaneously administered to Sprague-Dawley male rats from days 6 to 36 postpartum at doses of 50 to 1,000 mg/kg per day. Moxalactam (a cephamycin antibiotic which will be referred to as a cephalosporin for convenience throughout), which contains the MTT side chain, was used as a positive control and was administered at 100 to 1,000 mg/kg per day, and cephalothin, which lacks an MTT side chain, was used as the negative control at 1,000 mg/kg per day. Moxalactam caused a significant reduction in testicular and seminal vesicle weights in 37-day-old animals, and histological examination revealed bilateral multifocal atrophy of the seminiferous tubules at all dose levels. Animals reared to reproductive maturity had significant deficits in fertility, and histological examination revealed multifocal or diffuse atrophy of the seminiferous tubules at all doses with a severity greater than that observed in the 37-day-old animals. The histological findings were confirmed by marked reductions in testicular sperm production rates and cauda epididymal sperm numbers. Cephalothin and cefonicid had no treatment-related adverse effects on the sexual maturation of prepubertal, juvenile, or adult males. The absence (in cephalothin) or modification (in cefonicid) of the MTT side chain was not associated with adverse reproductive effects. The relevance of these findings to humans in prenatal and prepubertal stages of life cannot be determined at this time.
Age Factors↗
Human retroocular fibroblasts in vitro: a model for the study of Graves' ophthalmopathy.
Orbital connective tissue and extraocular muscles are histologically abnormal in patients with Graves' ophthalmopathy (GO). Although extraocular muscles have been extensively studied as a target for autoimmune attack in the disease, no system has been available to study retroocular fibroblasts in GO. We developed a technique to isolate fibroblasts from minced explants of connective tissue removed in the course of transantral orbital decompression surgery for GO. Postmortem specimens from individuals without evidence of thyroid disease were obtained from the same anatomical site. Confluent cells could be passaged at least 10 times with stable morphology and frozen with greater than 75% viability. An enzyme-linked immunosorbent assay was used to study the in vitro binding of serum immunoglobulin G (IgG) to these cells. We found no difference in the degree of specific binding between GO cells and cells from normal individuals. However, there was significantly greater binding of IgG from GO sera than of that from normal serum to retroocular GO fibroblasts. These results suggest that serum IgG autoantibodies against normal retroocular fibroblasts are present in some GO patients.
Adult↗