Endoscopic management of hemorrhage from a duodenal diverticulum.
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Aged↗
Biomedical subjects
S J Rogers
Publications and source records attributed to S J Rogers.
Partner notification with HIV-infected drug users: results of formative research.
The authors conducted formative research on the use of partner notification with HIV-infected drug users (i.e. those who use/abuse injectable drugs, crack or cocaine) in order to guide the development of an effective intervention for this population in New York City. Structured focus group and personal interviews were conducted with 25 in- and out-of-treatment drug users, 23 counsellors from a sexually transmitted disease (STD) clinic and a methadone maintenance treatment programme (MMTP), and nine experts in the field of HIV partner notification and/or substance abuse prevention and treatment. Results revealed factors associated with HIV-positive disclosure, the strengths and barriers of existing partner notification programmes and issues that should be considered in designing an effective intervention with HIV-infected drug users. Further research and planning activities are recommended before piloting and evaluating such a programme.
Ambulatory Care↗
Empirically supported comprehensive treatments for young children with autism.
Describes treatment of autism, a severe, chronic developmental disorder that results in significant lifelong disability for most persons, with few persons ever functioning in an independent and typical lifestyle. Within the past decade, a number of studies have reported significant changes in the outcomes of very young children with autism following intensive comprehensive treatment. The criteria for empirically supported treatments, as described by Lonigan, Elbert, and Johnson (this issue), were applied to reports of eight treatment efficacy studies published in peer-reviewed journals. Whereas positive outcomes are reported in every case, the field does not yet have a treatment that meets the present criteria for well-established or probably efficacious treatment. Hypothesized variables affecting outcomes that need to be rigorously tested include age at start of treatment, type of treatment used, intensity of treatment, and IQ and language levels at the start of treatment.
Adolescent↗
Laparoscopic thermal ablation of hepatic neuroendocrine tumor metastases.
BACKGROUND: Neuroendocrine tumor metastases to the liver are generally slow growing, but patients suffer from hormone hypersecretion despite aggressive multimodality therapy. A minimally invasive method of tumor ablation affords symptomatic improvement with minimal morbidity. METHODS: Radiofrequency electrical energy is delivered to tissues via a 4-prong catheter resulting in tissue heating to 60 to 70 degrees C and cell death. Porcine studies were conducted to define appropriate parameters for energy delivery and then applied to patients using laparoscopic techniques. RESULTS: In the porcine model 3.5 to 4 cm lesions were reproducibly created in 15 minutes using 30 to 50 W of power. The ablation process was monitored via temperature feedback from thermocouples in the catheter tips and by a hyperechoic blush noted on ultrasonography. Laparoscopic thermal ablation of 13 tumors in six patients with carcinoid (two patients), gastrinoma, insulinoma, nonsecreting islet cell cancer, or medullary thyroid cancer was performed. There were no intraoperative complications, and all patients were discharged the next day. Successful ablation was confirmed by spiral-computed tomography and by symptomatic improvement in patients with secreting tumors. CONCLUSIONS: Laparoscopic thermal ablation of hepatic tumors is a novel, minimally invasive method of providing effective cytoreduction of neuroendocrine tumors metastatic to the liver.
Aged↗
An ovine model of acute myocardial infarction and chronic left ventricular dysfunction.
In order to develop and validate an ovine model of myocardial infarction with subsequent impairement of left ventricular function, 15 instrumented sheep underwent selective microembolization of the left coronary arteries with 0.5 mL 90 microns polystyrene beads. Hemodynamics and plasma hormones were measured preembolization (baseline) and then at hours 2, 4, 6, and 12 and days 1, 2, 3, 5 and 7 postembolization. Of the 15 sheep studied, 2 (13%) died on the day of embolization from arrhythmias. In the remaining sheep, left ventricular systolic pressure and stroke work (both P < 0.001) were reduced promptly and remained below basal levels. Mean arterial pressure (P < 0.001) increased initially, then decreased to below basal levels by hour 6. Heart rate (P < 0.001) and left atrial pressure (P < 0.05) were increased while cardiac output was decreased (P < 0.05). Left ventricular ejection fraction at day 7 was reduced (38.8 +/- 3.5 vs 46.0 +/- 3.9% preembolization; P < 0.05). The cardiac enzymes creatine kinase (P < 0.001) and troponin-T (P < 0.001) were increased following microembolization and returned to basal levels by days 2 and 5 respectively. Plasma atrial and brain natriuretic peptides (both P < 0.001) and plasma renin activity (P < 0.005) were all increased following embolization. This ovine model mimics the hemodynamic and neurohumoral features of acute myocardial infarction, resulting in left ventricular dysfunction, and should prove suitable for the study of interventions in a number of these conditions.
Animals↗
Hypothalamo-pituitary-adrenal axis response to coronary artery embolization: an ovine model of acute myocardial infarction.
Although previous studies have described the hypothalamo-pituitary-adrenal (HPA) response to the stress of acute myocardial infarction, it is not possible to study the hormone changes immediately after infarction in humans. Accordingly, we have examined the HPA response to microembolization of coronary arteries in 13 sheep compared with 5 sham control sheep. Plasma vasopressin (AVP; P < 0.001), ACTH (P = 0.005) and cortisol (P = 0.005) were all increased 2 h (first sample time) after embolization. Plasma ACTH and cortisol levels returned to baseline levels by 6 h but plasma AVP levels did not return to baseline levels until more than 12 h after embolization. Plasma corticotrophin-releasing hormone (CRH) showed no significant change in response to embolization. In a subset of six animals which were sampled more frequently, the peak responses for plasma AVP, ACTH and cortisol occurred at 40 min after embolization. The maximum responses in any individual sheep observed at this time point were 744 pmol/l for AVP, 144 pmol/l for ACTH and 492 nmol/l for cortisol. CRH levels tended to increase across the first hour but these changes were not statistically significant. In conclusion, the stress hormone responses to microembolization of the coronary arteries have been defined in an ovine model of myocardial infarction. This model is suitable for studying the effects of novel treatments to reduce the stress of myocardial infarction.
Adrenocorticotropic Hormone↗
Brief report: early intervention in autism.
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Autistic Disorder↗
Intact and impaired memory functions in autism.
This study examined memory functions in individuals with autism. Based on previous evidence of executive function (EF) deficits, we hypothesized that subjects with autism would demonstrate a pattern of intact and impaired memory functions similar to that found in other groups with EF deficits, such as patients with frontal lobe pathology. We compared the performance of high-functioning children and adolescents with autism (n = 19) and clinical comparison subjects (n = 19) matched on sex, CA, and VIQ on measures of memory and EF. The group with autism performed significantly worse than comparison subjects on measures of temporal order memory, source memory, supraspan free recall, working memory, and EF, but not on short- and long-term recognition, cued recall, or new learning ability, consistent with the predictions of the EF theory. The cognitive measures were significantly more intercorrelated in the autism group than the comparison group, consistent with a limit in central cognition.
Adolescent↗
Imitation and pantomime in high-functioning adolescents with autism spectrum disorders.
A study was designed to test 2 alternative hypotheses--a symbolic hypothesis and an executive function hypotheses--for the imitation and pantomime deficits found in previous studies of autism. The subjects were 17 adolescent high-functioning subjects with autism spectrum disorders and 15 clinical comparison subjects who were matched on chronological age and verbal IQ. Meaning and sequence were manipulated in facial and manual imitation tasks. Sequence was manipulated in the pantomime and control tasks. Recognition memory and motor control tasks were matched to the experimental tasks. The results provided no support for the symbolic deficit hypothesis; meaning aided rather than hindered the performance of the group with autism. Partial support for the executive deficit hypothesis was found. There were no group differences on motor control tasks, and few on the memory control tasks, arguing against deficits in motor initiation, basic motor coordination, or visual recognition memory.
Adolescent↗
Glycine-induced hyponatremia in the rat: a model of post-prostatectomy syndrome.
Post-prostatectomy syndrome (PPS) is characterized by hyponatremia after absorption of glycine irrigant. To study the pathogenesis of this syndrome, adult male rats with ligated ureters were infused over 15 minutes with 7.5 ml/100 g body weight of isosmotic glycine (N = 9) or mannitol (N = 9) and were compared to non-infused, ureter-ligated controls (N = 9). Immediately post-infusion, plasma sodium had decreased similarly in glycine- and mannitol-infused animals (111 +/- 2 vs. 106 +/- 1 mmol/liter), but plasma osmolality remained at control levels in both groups (285 +/- 1 vs. 288 +/- 1 mOsm/kg). Two hours post-infusion, hyponatremia was stable in the mannitol group (108 +/- 1 mmol/liter), but in the glycine group plasma sodium increased significantly (to 120 +/- 1 mmol/liter). Plasma osmolality two hours post-infusion was maintained in both the glycine (287 +/- 2) and mannitol (292 +/- 2) groups. Brain water in glycine-infused animals (3.90 +/- 0.01 liter/kg dry wt) was not significantly different from the mannitol-infused group (3.85 +/- 0.01) and only 1.8% higher than non-infused controls (3.83 +/- 0.02). Brain tissue glycine did not differ between the three groups. In contrast, muscle water two hours post-infusion in the glycine group was 6% higher than mannitol-infused and 13% higher than non-infused animals. Muscle glycine content in the glycine group (67 +/- 4 mM/kg dry tissue) was increased when compared to both mannitol-infused (25 +/- 1) and non-infused (20 +/- 1) groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Prolonged paralysis due to nondepolarizing neuromuscular blocking agents and corticosteroids.
The long-term use of nondepolarizing neuromuscular blocking agents (ND-NMBA) has recently been implicated as a cause of prolonged muscle weakness, although the site of the lesion and the predisposing factors have been unclear. We report 3 patients (age 37-52 years) with acute respiratory insufficiency who developed prolonged weakness following the discontinuation of ND-NMBAs. Two patients also received intravenous corticosteroids. Renal function was normal but hepatic function was impaired in all patients, and all had acidosis. Electrophysiologic studies revealed low amplitude compound motor action potentials, normal sensory studies, and fibrillations. Repetitive stimulation at 2 Hz showed a decremental response in 2 patients. The serum vecuronium level measured in 1 patient 14 days after the drug had been discontinued was 172 ng/mL. A muscle biopsy in this patient showed loss of thick, myosin filaments. The weakness in these patients is due to pathology at both the neuromuscular junction (most likely due to ND-NMBA) and muscle (most likely due to corticosteroids). Hepatic dysfunction and acidosis are contributing risk factors.
Adrenal Cortex Hormones↗
Domains of the Childhood Autism Rating Scale: relevance for diagnosis and treatment.
The Childhood Autism Rating Scale (CARS) was factor analyzed. Three factors emerged: Social Impairment (SI), Negative Emotionality (NE), and Distorted Sensory Response (DSR). Unit-weight factor scales showed moderate-to-good internal consistency. Cross-sectional analyses demonstrated that autistic (AUT) subjects were distinguished from subjects with pervasive developmental disorders (PDD) and nonpervasive developmental disorders (NPDD) by higher scores on SI. An SI cutoff score of 26 classified individuals as autistic vs. nonautistic with 78% accuracy. Longitudinal analyses showed that DSR was stable over 6 months of treatment, with little indication of symptom reduction. SI decreased over time across the diagnostic groups, but still showed significant continuity over the period. NE was most malleable and apparently sensitive to the effects of treatment.
Autistic Disorder↗
Can standard measures identify subclinical markers of autism?
This study compared the executive function and theory-of-mind abilities of siblings of autistic individuals to those of siblings of learning-disabled controls. Three different analyses of the dependent measures provided convergent support for a potential subclinical marker in the executive function domain. No group differences in theory-of-mind abilities were found. However, power analyses revealed that the measures employed in this study, which are typically used with autistic individuals, were not sufficiently sensitive to detect any group differences that might exist in "unaffected" family members. Suggestions for future research are provided, including the need to develop more sensitive tasks that produce larger effects and measure more elementary cognitive operations.
Adolescent↗
Developmental aspects of attachment behavior in young children with pervasive developmental disorders.
OBJECTIVE: The present study applied a continuous, clinically based rating system to compare predictions about attachment behavior in autism resulting from three different theoretical views and to characterize differences in attachment behavior of young autistic children. METHOD: The attachment behaviors of 32 young children with autism or pervasive developmental disorder were examined in a modified "strange situation." Attachment behaviors were rated on a continuous scale and on the Ainsworth subscales. Attachment ratings were compared with several developmental variables, including chronological age, mental age, language level, and social level. RESULTS: The continuous rating scale distinguished signs of security from signs of insecurity, allowing for behavioral idiosyncracies in the expression of attachment behavior seen in autistic children. The study found that 50% of the children demonstrated some behaviors indicative of secure attachment, that no children were unattached, and that developmental level rather than severity of autism was the strongest predictor of attachment security. CONCLUSIONS: Autism does not preclude the development of secure attachment relationships in young children, but rather it delays the development of secure attachment and may alter the behavioral patterns that express attachment security.
Autistic Disorder↗
Executive function and social communication deficits in young autistic children.
Preschool-aged, autistic children were compared with both developmentally delayed children of similar non-verbal mental age and normally developing children of similar verbal skill on measures of executive function and social communication skills. Autistic children exhibited significantly more perseverative responses on a test of executive function when compared to both comparison groups. Autistic children also exhibited significantly fewer joint attention and social interaction behaviors. Moreover, a significant relationship was found between executive function skill and the two social communication skills, which was independent of group membership or verbal ability. Competing hypotheses to account for the relationship between executive function deficits and social communication deficits in autism are discussed.
Attention↗
Pathophysiology and treatment of acute ischemic stroke.
Risk factors, pathogenesis, clinical manifestations, diagnosis, and surgical and pharmacological treatment of ischemic stroke are reviewed. Risk factors play an important part in the pathogenesis of ischemic stroke. Knowledge of the complex metabolic and cellular changes that occur during ischemic stroke is rapidly growing. Choosing the correct treatment is dependent upon obtaining a thorough and accurate clinical assessment of the patient. Diagnostic tests help in determining the size, location, etiology, and characteristics of the lesion. Currently no single agent or mode of therapy appears to be most efficacious. Many drugs are still in the human clinical testing stage; promising agents include thrombolytics, low-molecular-weight heparin, and heparinoids. Hemodilution, pentoxifylline, epoprostenol, nimodipine, naloxone, and GM1 therapy have had mixed results in clinical trials, partly because some of these agents were not tested in enough patients to provide an accurate assessment of their efficacy. Atenolol and propranolol are ineffective. Ticlopidine and aspirin decrease the incidence of subsequent stroke but have not been tested in acute ischemic stroke. Heparin may be effective in preventing further cardioembolic stroke or in treating stroke in progress. Nondrug therapies include carotid endarterectomy and surgical decompression for cerebellar stroke. No single agent can be recommended for treatment of ischemic stroke at this time. Promising regimens include ancrod, low-molecular-weight heparin and heparinoids, or thrombolytics.
Acute Disease↗
Oxygen radical-mediated DNA damage by redox-active Cr(III) complexes.
The mechanism of DNA damage induced by Cr(III) complexes is currently unknown even though it is considered to be the ultimate biologically active oxidation state of chromium. In this study, we have employed the Salmonella reversion assay to identify mutagenic Cr(III) complexes. Cyclic voltammetry was used to differentiate the redox kinetics between mutagenic and selected nonmutagenic Cr(III) species. Plasmid relaxation of supercoiled DNA was employed to show in vitro interactions with plasmid DNA and correlate the interactions with the electrochemical behavior and biological activity. The results of this study demonstrate that the mutagenic Cr(III) complexes identified in the Salmonella reversion assay display characteristics of reversibility and positive shifts of the Cr(III)/Cr(II) redox couple consistent with the ability of these Cr(III) complexes to serve as cyclical electron donors in a Fenton-like reaction. These same mutagenic complexes display an ability to relax supercoiled DNA in vitro, presumably by the induction of single-strand breaks. Nonmutagenic complexes were selected to test different ligands to determine how the ligand directs the activity of Cr(III) complexes. All nonmutagenic complexes tested thus far have shown classical irreversibility, more negative reduction potentials, and an inability to relax supercoiled plasmid DNA. These results suggest that the mechanism by which chromium complexes potentiate mutagenesis involves an oxygen radical as an active intermediate. These data also demonstrate the effect of associated ligands with regard to the ability of a metal to generate an active redox center.
Chromium↗
Role of thrombin exosites in inhibition by heparin cofactor II.
We determined the role of specific thrombin "exosites" in the mechanism of inhibition by the plasma serine proteinase inhibitors heparin cofactor II (HC) and antithrombin (AT) in the absence and presence of a glycosaminoglycan by comparing the inhibition of alpha-thrombin to epsilon- and gamma T-thrombin (produced by partial proteolysis of alpha-thrombin by elastase and trypsin, respectively). All of the thrombin derivatives were inhibited in a similar manner by AT, either in the absence or presence of heparin, which confirmed the integrity of both heparin binding abilities and serpin reactivities of epsilon- and gamma T-thrombin compared to alpha-thrombin. Antithrombin activities of HC in the absence of a glycosaminoglycan with alpha-, epsilon, and gamma T-thrombin were similar with rate constants of 3.5, 2.4, and 1.2 x 10(4) M-1 min-1, respectively. Interestingly, in the presence of glycosaminoglycans the maximal inhibition rate constants by HC with heparin and dermatan sulfate, respectively, were as follows: 30.0 x 10(7) and 60.5 x 10(7) for alpha-thrombin, 14.6 x 10(7) and 24.3 x 10(7) for epsilon-thrombin, and 0.017 x 10(7) and 0.034 x 10(7) M-1 min-1 for gamma T-thrombin. A hirudin carboxyl-terminal peptide, which binds to anion-binding exosite-I of alpha-thrombin, dramatically reduced alpha-thrombin inhibition by HC in the presence of heparin but not in its absence. We analyzed our results in relation to the recently determined x-ray structure of D-Phe-Pro-Arg-chloromethyl ketone-alpha-thrombin (Bode, W., Mayr, I., Baumann, U., Huber, R., Stone, S. R., and Hofsteenge, J. (1989) EMBO J. 8, 3467-3475). Our results suggest that the beta-loop region of anion-binding exosite-I in alpha-thrombin, which is not present in gamma T-thrombin, is essential for the rapid inhibition reaction by HC in the presence of a glycosaminoglycan. Therefore, alpha-thrombin and its derivatives would be recognized and inhibited differently by HC and AT in the presence of a glycosaminoglycan.
Amino Acid Chloromethyl Ketones↗