Anderson, Douglas R. (National Cancer Institute, Bethesda, Md.), and Michael F. Barile. Ultrastructure of Mycoplasma hominis. J. Bacteriol. 90:180-192. 1965.-Both thin-sectioning and negative staining were used in an electron microscopic study of the morphology of pleuropneumonia-like organism (PPLO) strain HEp-2 (Mycoplasma hominis, type I) grown in an artificial liquid medium. The morphology is quite variable and seems to depend, in part, on the age of the culture. The smallest form observed ("elementary body") is 80 to 100 mmu in diameter. The internal components of the larger PPLO cells (0.5 to 1 mu) are variable-some have ribosomelike granules and nuclear areas of netlike strands, and others have only irregular dense areas in a pale groundplasm. Some of the forms have dense cytoplasmic bodies which look much like elementary bodies. Others have vacuoles which may contain structures which look like smaller organisms. Especially in older cultures, very large (10 mu) vacuolated organisms are seen, probably corresponding to the "large bodies" described by light microscopists. Filamented forms are also seen. These observations suggest several possible modes of reproduction, each perhaps operating under different cultural conditions or at different ages of the culture.

Journal Article↗

PubMed1965

Comparison of the ultrastructure of several rickettsiae, ornithosis virus, and Mycoplasma in tissue culture.

Anderson, Douglas R. (National Cancer Institute, Bethesda, Md.), Hope E. Hopps, Michael F. Barile, and Barbara C. Bernheim. Comparison of the ultrastructure of several rickettsiae, ornithosis virus, and Mycoplasma in tissue culture. J. Bacteriol. 90:1387-1404. 1965.-In an effort to make a valid comparison of the ultrastructure of several intracellular parasites, selected agents were propagated under identical conditions in a single type of tissue culture cell; such infected preparations were processed for examination by electron microscopy by use of a standardized procedure for fixation and embedding. The organisms studied were: the Breinl and E strains of epidemic typhus, Rickettsia prowazeki; the Bitterroot strain of R. rickettsii; the Karp strain of R. tsutsugamushi (R. orientalis); R. sennetsu; the P-4 strain of ornithosis virus; and the HEp-2 strain of Mycoplasma hominis type I. Each of the rickettsial species examined had a cell wall and a plasma membrane, and contained ribosomes and deoxyribonucleic acid (DNA) in a ground substance. However, certain differences were noted. Both strains of R. prowazeki contained numerous intracytoplasmic electron-lucent spherical structures (4 to 10 mmu), not previously described. R. sennetsu, unlike the other rickettsiae, was not free in the host cytoplasm but was always enclosed in a vacuole. R. rickettsii was observed intranuclearly and in digestive organelles of the host cell as well as in the cytoplasm. Cells infected with ornithosis virus contained several forms representing the stages in its life cycle. The "initial bodies," made up of ribosomes and DNA strands, were morphologically similar to the rickettsiae. In cultures infected with M. hominis, most of the cells became large and multinucleate. Although the Mycoplasma organisms were readily cultivated from these cultures, only a few could be found in the electron microscope preparations. These organisms were extracellular and lacked a cell wall, being bound only by a unit membrane. Again, the internal components were ribosomes and DNA strands. Under the uniform preparative conditions employed here, the three groups of organisms were morphologically distinguishable from one another.

Chlamydia↗

PubMed1965

Subcellular particles associated with human leukemia as seen with the electron microscope.

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Animals↗

PubMedDate not supplied

Acute pseudoaneurysm formation complicating balloon dilation of native coarctation: treatment by delayed surgical repair.

An 11-year-old boy developed an acute aortic pseudoaneurysm during balloon dilation of unoperated coarctation of the aorta. The pseudoaneurysm occurred despite the fact that the balloon catheter size did not exceed the diameter of the aorta at the diaphragm. Elective delayed surgical repair was successfully performed after 3 weeks of antihypertensive treatment when serial magnetic resonance imaging had demonstrated a reduction in the local tissue swelling.

Acute Disease↗

PubMedDate not supplied

Evaluation of myocardial perfusion using positron emission tomography in infants following a neonatal arterial switch operation.

This study was performed to examine the use of positron emission tomography (PET) as a method of evaluating myocardial perfusion after the arterial switch operation for correction of transposition of the great arteries. Eleven asymptomatic patients (median age 2.3 years, range 1.3-4.3 years) post successful neonatal arterial switch repair for transposition underwent cardiac PET scanning using N(13) ammonia before and after dipyridamole infusion. Reconstructed data from static scans were analyzed for regional perfusion defects before and after pharmacological stress. Simultaneous assessment of coronary flow before and after stress was performed using a Patlak graphical analysis of data from dynamic scans. Results obtained from PET scanning were correlated with patterns of coronary artery anatomy, electrocardiogram (ECG) recordings, and echocardiographic evaluation. PET scanning demonstrated normal distribution of myocardial perfusion before and after stress in all but one patient, who was found to have a discrete inferior transmural perfusion defect. The defect was well correlated with perioperative ECG changes and a complicated postoperative course. Myocardial blood flow before dipyridamole (0.690 ml/min/g) was similar to reported adult rest values. There was a small but significant (p < 0.002) increase in myocardial blood flow after dipyridamole stress with a mean coronary flow reserve of 1.19 (+/-0.103). Echocardiographic evaluation failed to demonstrate significant wall motion abnormalities in any of the patients. Cardiac PET scanning is a reliable noninvasive method for evaluation of myocardial perfusion in small children. In this study, the incidence of myocardial perfusion defects after the arterial switch operation is lower than previously reported. The data obtained concerning coronary flow and coronary flow reserve after the arterial switch need to be interpreted with caution because normal data in children are not available.

Ammonia↗

PubMedDate not supplied

Primary infantile glaucoma (congenital glaucoma).

Primary infantile glaucoma, commonly termed congenital glaucoma or trabeculodysgenesis, is an unusual, inherited connatal anomaly of the trabecular meshwork and anterior chamber angle which leads to obstruction of aqueous outflow, increased intraocular pressure, and optic nerve damage. Its pathogenesis is still disputed; most observers have not been able to document ultrastructurally a continuous endothelial membrane, as initially advanced by Barkan. Medical therapy for primary infantile glaucoma is accorded a supportive role; the primary, definitive treatment is surgical. Both goniotomy and trabeculotomy ab externo give similarly good results in the majority of patients. The prognosis in this disease is related to the time of its initial presentation, initial surgical intervention, degree of optic nerve damage, nature and quality of corneal enlargement and astigmatism, progressive refractive error, and anisometropic amblyopia. The inability to easily quantitate visual acuity and extent of visual loss in neonates makes these parameters less helpful in following patients than measurement of corneal diameter and intraocular pressure. However, even these data should not be relied upon exclusively to determine the quality or quantity of success in primary infantile glaucoma.

Anterior Chamber↗

PubMedDate not supplied

Prenatal exposure to cocaine. II: Effects on open-field activity and cognitive behavior in Sprague-Dawley rats.

Pregnant rats received subcutaneous injections of 15 mg/kg of cocaine twice daily (Cocaine-D), twice daily for two consecutive days at 5-day intervals (Cocaine-I), 0.9% saline (Saline) twice daily, or 1.5 mg/kg amfonelic acid (AFA) daily from gestational days 1-20. Offspring were tested for: rates of spontaneous alteration at postnatal days (PND) 32, 35, 40, and 45; acquisition and retention performance on a water maze task beginning at PND 30 and 60; entrance into and activity in an open-field apparatus at PND 60 and 180. The Cocaine-D offspring were less likely than Control offspring to enter the open field when tested at PND 60. The Cocaine-I offspring were hyperactive in the open-field apparatus when tested at PND 60. The drug treated offspring did not differ from the Saline control animals on all other measures. The failure of the Cocaine-D animals to enter the open field is consistent with neophobic behavior that we have observed before in rats exposed in utero to cocaine.

Analysis of Variance↗

PubMedDate not supplied

The management of elevated intraocular pressure with normal optic discs and visual fields. I. Therapeutic approach based on high risk factors.

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Adult↗

PubMedDate not supplied

Value of assessment of pretest probability of deep-vein thrombosis in clinical management.

BACKGROUND: When ultrasonography is used to investigate deep-vein thrombosis, serial testing is recommended for those who test negative initially. Serial testing is inconvenient for patients and costly. We aimed to assess whether the calculation of pretest probability of deep-vein thrombosis, with a simple clinical model, could be used to improve the management of patients who present with suspected deep-vein thrombosis. METHODS: Consecutive outpatients with suspected deep-vein thrombosis had their pretest probability calculated with a clinical model. They then underwent compression ultrasound imaging of proximal veins of the legs. Patients at low pretest probability underwent a single ultrasound test. A negative ultrasound excluded the diagnosis of deep-vein thrombosis whereas a positive ultrasound was confirmed by venography. Patients at moderate pretest probability with a positive ultrasound were treated for deep-vein thrombosis whereas patients with an initial negative ultrasound underwent a single follow-up ultrasound 1 week later. Patients at high pretest probability with a positive ultrasound were treated whereas those with negative ultrasound underwent venography. All patients were followed up for 3 months for thromboembolic complications. FINDINGS: 95 (16.0%) of all 593 patients had deep-vein thrombosis; 3%, 17%, and 75% of the patients with low, moderate, and high pretest probability, respectively, had deep-vein thrombosis. Ten of 329 patients with low pretest probability had the diagnosis confirmed, nine at initial testing and one at follow-up. 32 of 193 patients with moderate pretest probability had deep-vein thrombosis, three diagnosed by the serial (1 week) test, and two during follow-up. 53 of 71 patients with high pretest probability had deep-vein thrombosis (49 by the initial ultrasound and four by venography). Only three (0.6%) of all 501 (95% CI 0.1-1.8) patients diagnosed as not having deep-vein thrombosis had events during the 3-month follow-up. Overall only 33 (5.6%) of 593 patients required venography and serial testing was limited to 166 (28%) of 593 patients. INTERPRETATION: Management of patients with suspected deep-vein thrombosis based on clinical probability and ultrasound of the proximal deep veins is safe and feasible. Our strategy reduced the need for serial ultrasound testing and reduced the rate of false-negative or false-positive ultrasound studies.

Algorithms↗

PubMedDate not supplied

Effect of patient weight on the anticoagulant response to adjusted therapeutic dosage of low-molecular- weight heparin for the treatment of venous thromboembolism.

Data evaluating the safety of using weight-based dosing of low-molecular-weight heparin (LMWH) in obese patients are limited. Some manufacturers have recommended a maximum daily dose of LMWH not to be exceeded. The purpose of this study was to determine if body weight influenced the anticoagulant response to a weight-based dose of LMWH for the treatment of venous thromboembolism. Patients with serum creatinine levels < 150 micromol/l receiving the LMWH, dalteparin 200 anti-Xa IU/kg based on actual body weight subcutaneously once daily for the treatment of deep vein thrombosis or pulmonary embolism, were eligible for the study. Patients received a minimum of 5 days LMWH treatment. Patients had peak anti-Xa levels (IL Test Chromogenic assay) measured 3-4 h following their day 3 injection and trough anti-Xa levels measured immediately prior to injections on day 3 and 5. No dose adjustments were made on the basis of the anti-Xa levels. Patients were a priori stratified into three weight classes: (A) within 20% of ideal body weight (IBW) (n = 13); (B) 20-40% of IBW (n = 14), and (C) greater than 40% of IBW (n = 10). The largest patient weighed 190 kg and had a body mass index of 58. Mean daily LMWH doses were 14,030, 17,646 and 23, 565 IU for groups A, B and C, respectively. Mean (SD) trough anti-Xa levels on day 3 were 0.12 (0.05) anti-Xa IU/ml for group A, 0.11 (0.03) anti-Xa IU/ml for group B and 0.11 (0.03) anti-Xa IU/ml for group C (p > 0.2). Similar trough anti-Xa levels were observed on day 5. Mean (SD) peak anti-Xa levels on day 3 were 1.01 (0.20) anti-Xa IU/ml, 0.97 (0.21) anti-Xa IU/ml and 1.12 (0.22) anti-Xa IU/ml for groups A, B and C, respectively (p > 0.2). No thromboembolic or bleeding complications occurred during LMWH therapy in any patients. These findings suggest that body mass does not appear to have an important effect on the response to LMWH up to a weight of 190 kg in patients with normal or near normal renal function.

Adult↗

PubMedDate not supplied

Acquired type 2a von Willebrand's disease: response to immunoglobulin infusion.

A 75-year-old male presented with new symptoms of a bleeding diathesis associated with a decline in the functional activity of von Willebrand factor (type 2a von Willebrand's disease). Replacement therapy was ineffective and he was subsequently treated with intravenous immunoglobulin (IvIg). IvIg not only caused symptomatic improvement but was shown to transiently restore the depleted von Willebrand factor intermediate and high molecular weight multimers. Subsequent periodic IvIg infusions have been used successfully to treat bleeding complications in this patient over the past 3 years. A secondary cause for the acquired von Willebrand's disease has not been identified.

Aged↗

PubMedDate not supplied

Mechanics of the healed meniscus in a canine model.

The mechanical behavior of the intact canine stifle joint was studied, using a surgical model of meniscal injury and repair. Thirty-eight animals were divided into five study groups: Group S received only a sham arthrotomy (without a meniscal incision), Groups P13 and P26 received peripheral medial meniscal incisions, and Groups R13 and R26 received radial medial meniscus incisions. All meniscal incisions were repaired anatomically with absorbable suture. Groups P13 and R13 were sacrificed at 13 weeks following surgery and Groups P26 and R26 at 26 weeks. Following sacrifice, the joints were subjected to gross and histologic examination, and structural and material properties testing. All meniscal repairs healed, and the peripheral repairs were virtually invisible, with no articular damage. The radial repairs healed with 3 to 5 mm wide fibrovascular scars, and several joints demonstrated articular erosions. The radial repair tissue contained unorganized collagen bundles and ground substance deficient in mucopolysaccharides. Groups S, P13 and P26 demonstrated no statistically significant differences between test and control limbs in compressive force-displacement behavior, input energy (EI), and ratio of dissipated to input energy (ED/EI). There were significant test-control differences in the load-displacement characteristics of Groups R13 (P less than 0.05) and R26 (P less than 0.05), with the repaired joint stiffer than the control. EI decreased 26% in Group R13 (not significant) and 34% in Group R26 (P less than 0.05), while the ratio ED/EI increased from 27% to 44% in Group R13 (not significant) and from 31% to 38% in Group R26 (P less than 0.05). Medial compartment contact area did not change significantly in either peripheral repair group, but decreased by 25% in Group R13 (P less than 0.05) and by 13% in Group R26 (P less than 0.05). Yield stress, maximum stress, and Young's modulus decreased significantly (P less than 0.05) relative to the controls in tensile tests of the radial repair tissue. There were no significant changes in these properties from 13 to 26 weeks. We concluded that in this animal model, the mechanical function of the meniscus is restored following repair of peripheral longitudinal lesions; however, it appears that in the radial repairs, progressive spreading at the repair site (filled by a fibrovascular scar) altered normal meniscal geometry and structure, adversely influencing mechanical function. Future studies may document whether protective measures (immobilization, limited weightbearing, etc.) can preserve normal mechanical function following repair of radial lesions.

Animals↗

PubMedDate not supplied

The impact of worksite-based health risk appraisal on health-related outcomes: a review of the literature.

PURPOSE: To provide a brief history of the development and evolution of health risk appraisal (HRA) and to review studies published in peer-reviewed journals that address the impact of worksite-based HRA on health-related outcomes. METHOD: The Centers for Disease Control and Prevention conducted the primary literature search, identifying seven articles through a bibliographic search of major health databases, manual search of specific journals, and reference list search. We identified four additional studies from our personal experience and our manual search of previous reviews. IMPORTANT FINDINGS: Several studies reported positive changes in seat-belt use and self-reported physical activity associated with HRA participation, and changes in other health-related outcomes after HRA participation were also reported. Evidence supporting causal inference is lacking, however, because of the many threats to internal validity in studies completed to date. Almost no research has addressed the impact of HRA on health-related outcomes in the early "prebehavioral" stages of the change process, despite the theoretical and applied focus of HRA on these types of outcomes. CONCLUSIONS: On the basis of the small number of studies in the literature, evidence is weak regarding the impact of HRA itself on health-related outcomes. There is suggestive evidence for the effectiveness of HRA when it is used in a comprehensive worksite health promotion program. Future research should focus on the impact of HRA on variables in the early stages of the change process, such as awareness and commitment, rather than on behavioral outcomes. Research should also address specific characteristics of HRA instruments and implementation approaches.

Adult↗