Factor X values as a means to assess the extent of oral anticoagulation in patients receiving antithrombin drugs.
Explore the source record for details and available documents.
Administration, Oral↗
Biomedical subjects
S Kahn
Publications and source records attributed to S Kahn.
Circadian relationships between circulating atrial natriuretic peptides and serum calcium and phosphate in healthy humans.
Long-acting natriuretic peptide (LANP), vessel dilator (VSDL), and atrial natriuretic factor (ANF) consisting of amino acids (aa) 1 to 30, 31 to 67, and 99 to 126, respectively, of the 126-aa ANF prohormone circulate in humans. Among the biologic properties of these peptides is the ability of ANF to decrease intracellular calcium concentrations. To determine if atrial natriuretic peptides are directly related to serum calcium and/or phosphate in healthy normocalcemic humans, we examined 21 24-hour profiles of VSDL, LANP, ANF, and serum calcium and phosphate in 14 healthy humans. VSDL, LANP, and ANF each had significant (P < .001) circadian rhythms, with peak concentrations late during sleep (at 4:00 AM) being nearly twice the concentrations in the afternoon and evening. Serum calcium and phosphate also had significant circadian rhythms (P < .001) with troughs nearly opposite to those of the atrial natriuretic peptides, suggesting that atrial peptides may be important in the modulation of the circadian rhythms of calcium and phosphate. The nearly identical circadian rhythms of the atrial natriuretic peptides and of parathyroid hormone (PTH) reported by others, along with evidence that PTH may increase atrial peptide release, suggest that some of the effects attributed to PTH may be mediated by atrial natriuretic peptides.
Adult↗
Left ventricular hypertrophy on electrocardiogram: prognostic implications from a 10-year cohort study of older subjects: a report from the Bronx Longitudinal Aging Study.
OBJECTIVE: The objective of this study was to report on the prevalence, incidence and prognosis of left ventricular hypertrophy (LVH) on the electrocardiogram (ECG) in a cohort of ambulatory older men and women. DESIGN: A prospective, longitudinal study of 10 years duration with ECGs obtained at baseline and on an annual basis. SETTING AND PATIENTS: A community-based cohort study consisting of 459 subjects (aged 75-85, mean age 79 years). MEASUREMENTS: Baseline and follow up ECGs were interpreted using the Minnesota Code. Prevalence and incidence of LVH and ECG were determined as well as regression of ECG LVH. Clinical event rates measured were incidence of total mortality, myocardial infarction (MI, fatal and non-fatal), cardiovascular mortality, cardiovascular disease (fatal and non-fatal), stroke (fatal and non-fatal), all-cause dementia, and multi-infarct dementia. Differences in event rates between groups (those subjects with and without LVH) were compared as tests between proportions. A Cox Proportional Hazards Regression Analysis was performed to compare the relative independent predictive values of different competing factors, including age, gender, serum cholesterol, digitalis use, body mass, index, Blessed Dementia Scale, cigarette smoking, LVH at baseline, LVH ar baseline (persisting), new LVH, new LVH (persisting), new LVH (regressed), previous MI by history of ECG, hypertension by history, and cardiomegaly by X-ray (cardiothoracic ratio > or = 50%). RESULTS: At baseline, 9.2% of subjects (n = 42) had LVH on ECG and a mortality rate of 11.7/100 persons years versus 4.9/100 persons years for subjects without baseline LVH (P < .0001), and MI rate of 7.5/100 persons years with LVH versus 2.6/100 persons years without LVH (P < .0001), and a cardiovascular mortality rate of 7.2/100 persons years without LVH versus 2.7/100 person years without LVH. Subjects who developed new LVH on ECG (n = 39) had a mortality rate of 14.4/100 person-years compared with 4.4/100 person-years for those without LVH (P < .0001), a cardiovascular mortality rate of 11.1/100 person years versus 2.0/100 person years without LVH (P < .0001), and an MI rate of 6.1/100 person years versus 2.0/100 person years without LVH (P < .01). Subjects in whom the ECG LVH pattern disappeared over time had fewer cardiovascular mortal and morbid events than those with persistent LVH. According to the regression analyses, persistent LVH from baseline was an independent predictor of MI, overall cardiovascular disease, and total mortality. Newly developing LVH with subsequent regression was an independent predictor of overall cardiovascular disease and death. CONCLUSIONS: An increased prevalence and incidence of LVH on ECG, irrespective cause, is associated with a poor prognosis in very old men and women. Regression of ECG LVH in older people, irrespective of cause, may confer improvement in risk for cardiovascular disease.
Aged↗
Trypanosoma cruzi amastigote adhesion to macrophages is facilitated by the mannose receptor.
Trypanosoma cruzi is an obligate intracellular protozoan parasite. The mammalian stage of the parasite life cycle describes amastigotes as an intracellular form that replicates, and trypomastigotes as an extracellular form that disseminates and invades cells. Recent studies, however, have demonstrated that amastigotes circulate in the blood of infected mammals and can invade mammalian cells. In this report, a T. cruzi surface glycoprotein gene, SA85-1.1, was expressed as an immunoglobulin chimera, and this recombinant globulin was used to screen normal mouse tissues for adhesive interactions. This approach identified a subset of macrophages in the skin and peripheral lymph node that bind the T. cruzi surface glycoproteins through the mannose receptor. To further examine the T. cruzi mannose receptor carbohydrate ligands, the interaction between T. cruzi and the mannose-binding protein, a mammalian lectin with similar carbohydrate binding specificities as the mannose receptor, was examined. These studies demonstrated that the mannose-binding protein recognized amastigotes, but not trypomastigotes or epimastigotes, and suggested that amastigotes would also be recognized by the mannose receptor. Therefore, amastigote adhesion to macrophages was investigated, and these experiments demonstrated that the mannose receptor contributes to amastigote adhesion. The data identify the first mammalian lectins that bind to T. cruzi, and are involved in T. cruzi invasion of mammalian cells. The data suggest that amastigotes and trypomastigotes may have developed different mechanisms to adhere to and invade host cells. In addition, it has been established that IFN-gamma-activated macrophages express low levels of the mannose receptor and are trypanocidal; this suggests that the interaction between amastigotes and the mannose receptor enables amastigotes to increase their adherence with a population of macrophages that are nontrypanocidal and permissive for their intracellular replication.
Animals↗
Continuing the dialogue: a response to Draper's critique of Fawcett's 'Conceptual models and nursing practice: the reciprocal relationship'.
In their response to Draper's (1993) critique of Fawcett's (1992) paper 'Conceptual models and nursing practice: the reciprocal relationship', the authors argue that Draper's critique is flawed. They point out that Draper fails to acknowledge the diversity within the positivist movement, makes logical leaps, and fails to acknowledge Fawcett's long-standing distinction between middle-range theories and conceptual models and her discussions of the differences in the criteria to be used when evaluating conceptual models and theories.
Clinical Nursing Research↗
The impact of substance use on mortality and morbidity from thermal injury.
Alcohol and drug use have been associated with increased mortality and morbidity from thermal injury. To determine whether substance users (SUs) differed from controls, 398 burn patients were studied, of whom, 161 had a positive drug screen for either ethanol, cannabinoids, cocaine metabolites, amphetamines, phencyclidine, or benzodiazepines. SUs versus controls showed no difference in age, but had a significantly greater percentage of total burn surface area (TBSA) (25 vs. 17%), inhalation injury (29 vs. 7%), and mortality (14 vs. 3%). The alcohol users (AUs) and drug users (DUs) were similar in relation to sex, age, inhalation injury, percentage of TBSA, and type of burn. DU patients experienced the same increase in inhalation injury as the AU group compared to controls. The mortality of AU patients was twice that of DU patients and six times that of controls. The best independent predictors of death were age, inhalation injury, percentage of TBSA (p < 0.001), and ethanol use (p < 0.02).
Adolescent↗
Suppression of ventricular output by noise in the atrial channel in a dual chamber pacemaker.
In a pacemaker dependent, 60-year-old man with complete heart block, programming high (5.0 V and 1.0 ms) atrial output and 5.0 volt and 0.5 ms ventricular output while in the DDD mode of a pulse generator, resulted in loss of ventricular channel output with resulting asystole, while the simultaneous, pulse generator produced ECG interpretation channel falsely indicated continuing ventricular channel output. Ventricular pacing was promptly restored by programming to the emergency VVI mode. At later operation the atrial lead was determined to be defective, with a low impedance, while the ventricular lead was intact (lead impedance telemetry was not available). The manufacturer has acknowledged a pulse generator design anomaly that may occur in the setting of a low atrial impedance and issued a Health Safety Alert.
Artifacts↗
The effect of alendronate on renal tubular reabsorption of phosphate.
We report the effects of alendronate on phosphate homeostasis in two patients. In a woman with postmenopausal osteoporosis, the infusion of alendronate (7.5 mg intravenously daily for 4 consecutive days) was not associated with secondary hyperparathyroidism despite a reduction in serum calcium. This was associated with a rise in serum phosphate and TmP/GFR. This response contrasted with those observed in 14 other patients with osteoporosis, in whom PTH rose significantly following the infusion of alendronate in association with a significant fall in serum phosphate and TmP/GFR. The second patient, a woman with Paget's disease, was treated with intravenous alendronate (10 mg daily for 5 consecutive days) on two occasions for relapse of disease activity. On the first occasion there was a 150% rise in serum PTH associated with a fall in serum phosphate and TmP/GFR. On the second occasion, when the rise in serum PTH was less marked, there was a rise in serum phosphate and TmP/GFR. We conclude that alendronate may increase renal tubular reabsorption of phosphate, but that this effect is usually offset by secondary hyperparathyroidism.
Absorption↗
Intra-individual variation in fasting urinary calcium- and hydroxyproline-creatinine ratios measured in metabolic bone clinic patients as both outpatients and inpatients.
The total intra-individual variation of fasting urinary calcium- and hydroxyproline-creatinine ratios were determined both as outpatients and as inpatients in 46 patients with metabolic bone disorders, including 20 women with osteoporosis. The intra-individual variation of both measurements was reduced considerably by collecting samples in the ward rather than in the outpatient setting, although this was not the case for a sub-group of osteoporotic women. The large intra-individual variation observed for calcium and hydroxyproline (30-40% in osteoporotic women) can give rise to misclassification in screening for fast bone losers. The very large critical difference required (109% and 94%, respectively, for calcium and hydroxyproline) for two results to reflect a significant change, is a major limitation in the use of these analytes for monitoring bone resorption in menopausal and osteoporotic women.
Aged↗
The regulatory domain of protein kinase C beta 1 contains phosphatidylserine- and phorbol ester-dependent calcium binding activity.
Certain isoforms of protein kinase C (PKC) require both Ca2+ and phospholipid for optimum activity. However, little is known about the nature of the interaction between PKC and Ca2+. The present study demonstrates that the isolated regulatory domain of PKC beta 1, when synthesized as a fusion protein in Escherichia coli, binds 45Ca2+ with high affinity, but only in the presence of phosphatidylserine or 12-O-tetradecanoyl-phorbol-13-acetate. This binding is highly selective for Ca2+ since it is preferentially inhibited by excess non-radioactive Ca2+ when compared with the cations Mg2+, Mn2+, Na+, or K+. It appears, therefore, that the binding of Ca2+ to PKC requires a complex tertiary structure in the regulatory domain.
Base Sequence↗
SA85-1 proteins of Trypanosoma cruzi lack sialidase activity.
Explore the source record for details and available documents.
Animals↗
Polypoid lesions at the anorectal junction: barium enema findings.
Although the anorectal junction is easily accessible, this area may be difficult to evaluate both radiologically and endoscopically because it is relatively collapsed. This pictorial essay illustrates the barium enema radiographic findings and reviews the radiologic and endoscopic pitfalls in the diagnosis of lesions of the anorectal junction.
Adenocarcinoma↗
Surgical management of pediatric renal trauma: an urban experience.
This study was undertaken to review our operative experience in the management of pediatric renal trauma. Over a 2-year period (August 1988 to August 1990) 25 of 60 children undergoing celiotomy sustained renal injuries. There were 22 boys and three girls ranging in age from 5 to 18 years. Eighty-four per cent were victims of gunshot wounds, 12 per cent were stabbed, and 4 per cent sustained blunt trauma. The 25 injured children sustained a total of 45 individual organ injuries. Only 16 per cent required a nephrectomy, while the great majority (84%) were managed with renal sparing procedures. When we compared survivors to nonsurvivors, there was more thoracic and vascular injury along with more blood transfusion requirements in nonsurvivors. There was no statistical difference in Pediatric Trauma Score (PTS) between survivors and nonsurvivors (9.8 +/- 0.26 vs 9.5 +/- 1.5). Preoperative intravenous pyelographies (IVPs) performed in 52 per cent of all patients demonstrated the site of injury, presence of contralateral function as well as the anatomic position of the kidneys. We conclude that renal injury is common following penetrating abdominal trauma in childhood, however, these injuries can be managed by early operation with renal sparing procedures. There is a high incidence of associated intra-abdominal injury in those who have sustained penetrating renal trauma, but mortality is more common in patients sustaining associated thoracic and vascular injuries. An IVP should be performed, even in the absence of hematuria, when trauma trajectory strongly suggests urologic injury. This study also illustrates the sharp rise in drug-related urban violence with an associated increase in pediatric renal trauma.
Abdomen↗
The hidden cost of AIDS.
Explore the source record for details and available documents.
Acquired Immunodeficiency Syndrome↗
Polyreactive autoantibodies to negatively charged epitopes following Trypanosoma cruzi infection.
During the course of many human autoimmune diseases, antibodies which recognize negatively charged epitopes on self antigens are detected. Trypanosoma cruzi, an intracellular protozoan parasite capable of infecting a wide variety of vertebrates, is the cause of Chagas disease in humans. Infection with the parasite frequently results in autoimmune and inflammatory pathology. We report here on an affinity-purified population of antibodies that bind to a broad class of antigens that contain runs of acidic amino acids, including tubulin. Although these antibodies can be isolated from both uninfected and T. cruzi chronically infected C3H/He mice, the antibodies from the normal mice (the natural autoantibodies) bind to tubulin poorly at physiological pH, whereas the antibodies isolated from the infected animals bind well at physiological pH. We propose that similar processes may occur in humans following other infections accounting for the detection of antibodies to negatively charged epitopes in a variety of autoimmune diseases.
3T3 Cells↗
Evaluation of recombinant trypomastigote surface antigens of Trypanosoma cruzi in screening sera from a population in rural northeastern Brazil endemic for Chagas' disease.
A perfect serologic test for infection with Trypanosoma cruzi does not exist. This study uses recombinant T. cruzi surface proteins in the antibody capture enzyme linked immunoabsorption assay (ELISA); and compares this approach to the more standard immunofluorescence assay (IFA). Three recombinant antigens are studied: F1-160 corresponding to the 160 kDa flagellar associated surface protein of trypomastigotes (the motile form of T. cruzi in mammalian infections); and SA 85-1.1 and 1.2 corresponding to different members of the 85 kDa family of surface proteins expressed by trypomastigotes and amastigotes (the replicative, non-motile form of T. cruzi in mammalian infections). Each recombinant antigen is found to be highly specific (range 86-94%) but relatively insensitive (range 36-52%) when used to screen for antibodies to T. cruzi. Defining seropositivity as reactivity to any of the three recombinant antigens markedly increases the sensitivity (72%) with only a minor reduction in specificity (82%). Thus, employing recombinant T. cruzi antigens to screen for T. cruzi infection has promise, but improvements in sensitivity must be made before widespread utilization is recommended.
Animals↗
Cardiomegaly on chest x-ray: prognostic implications from a ten-year cohort study of elderly subjects: a report from the Bronx Longitudinal Aging Study.
This report is from a 10-year cohort study of community-dwelling elderly men and women. Mean age at the time of entry into the study was 79 years. Annual chest x-ray studies were performed, and data are presented regarding prevalence, incidence, and prognosis of cardiomegaly. Cardiomegaly was defined as a transverse diameter of the cardiac silhouette greater than or equal to 50% of the transverse diameter of the chest (increased cardiothoracic ratio). At the time of entry into the study 110 subjects (23%) had cardiomegaly. After 10 years, 51% of the subjects with cardiomegaly at baseline died compared with 33% of the subjects without cardiomegaly (mortality rate = 9.1 vs 4.8/100 person-years respectively; p = 0.014). Cardiovascular disease incidence was also higher for those with preexisting cardiomegaly at baseline (rate 9.1 vs 6.1/100 person-years; p = 0.0001). According to the Cox proportional hazards regression analysis, age, cardiomegaly, diabetes, and prior evidence of myocardial infarction were independent predictors for death in this cohort. Similarly, the best predictive variables for cardiovascular disease were age, diabetes, prior evidence of myocardial infarction, and cigarette smoking. Of the 359 subjects without cardiomegaly at baseline, 108 (30%) showed evidence of new cardiomegaly, and their risk of cardiovascular disease was 1.8 times that of subjects whose test results were negative for cardiomegaly throughout the study (p = 0.003). Thus cardiomegaly, as defined by an increased cardiothoracic ratio on x-ray films, irrespective of cause, is associated with a poor prognosis in very elderly men and women.
Aged↗
Perceptual organization and attention.
It is widely assumed that the grouping of the visual field first described by the Gestalt psychologists and the related phenomenon of texture segregation occur very early in the processing of visual information and involve preattentive processes. All the recent evidence supporting this assumption comes from visual search experiments in which the subject is actively looking for a target and attending to the stimulus. The question at issue is whether these kinds of patterns are perceived under conditions of inattention, i.e., when observers are not searching for them. We performed six experiments to determine whether texture segregation and grouping by similarity or proximity are perceived under conditions of inattention. On the first two trials subjects were asked to report the longer arm of a briefly presented cross which was surrounded by a pattern of ungrouped small elements. On the third trial and subsequent control trials these elements were configured into grouping patterns and subjects queried about them immediately following their line length reports. The results establish that neither texture segregation nor grouping by similarity of lightness or proximity are perceived under conditions of inattention. They support the conclusion that there is an earlier stage of processing than that referred to as preattentive.
Adult↗