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Biomedical subjects

M J Rosen

Publications and source records attributed to M J Rosen.

At least 19 recordsLinked to original sources
PubMed2006

Diaphragm pacing with natural orifice transluminal endoscopic surgery: potential for difficult-to-wean intensive care unit patients.

BACKGROUND: Up to 50% of the patients in the intensive care unit (ICU) require mechanical ventilation, with 20% requiring the use of a ventilator for more than 7 days. More than 40% of this time is spent weaning the patient from mechanical ventilation. Failure to wean from mechanical ventilation can in part be attributable to rapid onset of diaphragm atrophy, barotrauma, posterior lobe atelectasis, and impaired hemodynamics, which are normally improved by maintaining a more natural negative chest pressure. The authors have previously shown that laparoscopic implantation of a diaphragm pacing system benefits selected patients. They now propose that an acute ventilator assist with interventional neurostimulation of the diaphragm in the ICU is feasible and could facilitate the weaning of ICU patients from mechanical ventilation. Natural orifice transluminal endoscopic surgery (NOTES) has the potential to expand the benefits of the diaphragm pacing system to this acute patient population by allowing it to be performed at the bedside similarly to insertion of the common gastrostomy tube. This study evaluates the feasibility of this approach in a porcine model. METHODS: Pigs were anesthetized, and peritoneal access with the flexible endoscope was obtained using a guidewire, needle knife cautery, and balloon dilation. The diaphragm was mapped using a novel endoscopic electrostimulation catheter to locate the motor point (where stimulation provides complete contraction of the diaphragm). An intramuscular electrode then was placed at the motor point with a percutaneous needle. The gastrotomy was managed with a gastrostomy tube. RESULTS: Four pigs were studied, and the endoscopic mapping instrument was able to map the diaphragm to identify the motor point. In one animal, a percutaneous electrode was placed into the motor point under transgastric endoscopic visualization, and the diaphragm could be paced in conjunction with mechanical ventilation. CONCLUSIONS: These animal studies demonstrate the feasibility of transgastric mapping of the diaphragm and implantation of a percutaneous electrode for therapeutic diaphragmatic stimulation.

Animals↗
PubMed2006

The single-staged approach to the surgical management of abdominal wall hernias in contaminated fields.

INTRODUCTION: The surgical treatment of large ventral hernias with accompanying contamination is challenging. We have reviewed our institution's experience with single-staged repair of complex ventral hernias in the setting of contamination. METHODS: We retrospectively reviewed the medical records of all patients who underwent ventral hernia repairs in the setting of a contaminated field. Pertinent details included baseline demographics, reason for contamination, operative technique and details, postoperative morbidity, mortality and recurrence rates. RESULTS: Between December 1999 and January 2006, 19 patients were identified with ventral hernia repairs performed in contaminated fields. There were 6 males and 13 females with a mean age of 61 years (40-82), ASA 3.2 (2-4), and BMI of 34 kg/m(2) (20-65). Fourteen patients had prior mesh: prolene (9), composix (3), goretex (1), and alloderm (1). Reasons for contamination included: mesh infection (14), enterocutaneous fistula (7), concomitant bowel resection (8), chronic non-healing wound (2), and necrotizing fasciitis (1). Operative approaches included primary repair (3), component separation without reinforcement (2), and with prosthetic reinforcement (9). In five patients the fascia could not be reapproximated in the midline and the defect was bridged with surgisis (1), Marlex (1), lightweight polypropylene (1) placed in the retrorectus space, and alloderm (2). Mean operative time was 260 min (90-600). Twelve postoperative complications occurred in nine (47%) patients and included wound infection (6), respiratory failure (1), ileus (2), postoperative hemorrhage (1), renal failure (1), and atrial fibrillation (1). One patient died in this series. During routine follow-up two recurrences were identified by physical exam. CONCLUSIONS: This study shows that single-stage treatment of ventral hernias in contaminated fields can be accomplished with a low recurrence rate and acceptable morbidity in these extremely challenging patients.

Adult↗
PubMed2006

Combined open and laparoscopic approach to chronic pain following open inguinal hernia repair.

INTRODUCTION: Chronic groin pain is the most common long-term complication after open inguinal hernia repair. Traditional surgical management of the associated neuralgia consists of injection therapy followed by groin exploration, mesh removal, and nerve transection. The resultant hernia defect may be difficult to repair from an anterior approach. We evaluate the outcomes of a combined laparoscopic and open approach for the treatment of chronic groin pain following open inguinal herniorrhaphy. METHODS: All patients who underwent groin exploration for chronic neuralgia after a prior open inguinal hernia repair were prospectively analyzed. Patient demographics, type of prior hernia repair, and prior nonoperative therapies were recorded. The operation consisted of a standard three trocar laparoscopic transabdominal preperitoneal hernia repair, followed by groin exploration, mesh removal, and nerve transection. Outcome measures included recurrent groin pain, numbness, hernia recurrence, and complications. RESULTS: Twelve patients (11 male and 1 female) with a mean age of 41 years (range 29-51) underwent combined laparoscopic and open treatment for chronic groin pain. Ten patients complained of unilateral neuralgia, one patient had bilateral complaints, and one patient complained of orchalgia. All patients failed at least two attempted percutaneous nerve blocks. Prior repairs included Lichtenstein (n=9), McVay (n=1), plug and patch (n=1), and Shouldice (n=1). There were no intraoperative complications or wound infections. With a minimum of 6 weeks follow up, all patients were significantly improved. One patient complained of intermittent minor discomfort that required no further therapy. Two patients had persistent numbness in the ilioinguinal nerve distribution but remained satisfied with the procedure. CONCLUSIONS: A combined laparoscopic and open approach for postherniorrhaphy groin pain results in good to excellent patient satisfaction with no perioperative morbidity. It may be the preferred technique for the definitive management of chronic neuralgia after prior open hernia repair.

Adult↗
PubMed2004

Anti-Saccharomyces cerevisiae antibody (ASCA) positivity is associated with increased risk for early surgery in Crohn's disease.

BACKGROUND: Anti-Saccharomyces cerevisiae antibodies (ASCA) are a specific but only moderately sensitive diagnostic marker for Crohn's disease. We sought to explore the role of ASCA as a prognostic marker for aggressive disease phenotype in Crohn's disease. AIMS: To determine the role of ASCA status as a risk factor for early surgery in Crohn's disease. SUBJECTS: We performed a case control study in a cohort of patients, newly diagnosed with Crohn's disease, between 1991 and 1999. All patients were followed for at least three years. Case subjects (n = 35) included those who had major surgery for Crohn's disease within three years of diagnosis. Controls (n = 35) included patients matched to cases for age, sex, disease location, and smoking status, and who did not undergo major surgery for Crohn's disease within three years of diagnosis. METHODS: Blinded assays were performed on serum for ASCA (immunoglobulin (Ig)A and IgG). A paired analysis of cases-controls was performed to test for the association between ASCA status and risk of early surgery. RESULTS: ASCA IgA was strongly associated with early surgery (odds ratio (OR) 8.5 (95% confidence interval (CI) 2.0-75.9); p = 0.0013). ASCA IgG+ and ASCA IgG+/IgA+ patients were also at increased risk for early surgery (OR 5.5 (95% CI 1.2-51.1), p = 0.0265; and OR 5.0 (95% CI 1.1-46.9), p = 0.0433, respectively). The association between ASCA and early surgery was evident in patients requiring surgery for ileal or ileocolonic disease. CONCLUSIONS: Patients with Crohn's disease who are positive for ASCA IgA, IgG, or both, may define a subset of patients with Crohn's disease at increased risk for early surgery.

Adult↗
PubMed2002

A bird's eye view: top down intracellular analyses of auditory selectivity for learned vocalizations.

The "song system" refers to a group of interconnected brain nuclei necessary for the utterance of learned song and for the generation of vocal plasticity important to both song learning and adult song maintenance. Although song learning and, in some species, song maintenance depend on auditory feedback, how audition influences vocalization remains unknown. One attractive idea is that auditory signals propagate directly to those telencephalic nuclei implicated in song patterning, providing a convenient substrate for sensorimotor integration. Consistent with this idea, auditory neurons highly selective for the bird's own song have been detected in telencephalic song nuclei, and lesions of these structures can impair song perception as well as song production. This review discusses evidence for an auditory-perceptual role of the song system, the anatomical pathways by which auditory information enters the song system, the synaptic events underlying highly selective action potential responses to learned song, and the possible roles such activity could play in song learning and maintenance.

Acoustic Stimulation↗
PubMed2001

The relationship between the interfacial properties of surfactants and their toxicity to aquatic organisms.

In previous work, the toxicity of several anionic and nonionic surfactants to rotifer (Brachionus calyciflorus) was shown to be highly correlated with interfacial activity. In this study, the relationship between interfacial properties of surfactants and their effects on aquatic organisms is extended to include the toxicity of the cationic surfactant class (homologues of alkyl trimethylammonium chloride and alkyl hydroxyethyl dimethylammonium chloride) to green algae (Selenastrum capricornutum) and the bioconcentration of linear alkylbenzene sulfonate (LAS) isomers and homologues by fish (Pimephales promelas and Ictalurus punctatus). In each case, the interfacial activity is expressed by the physicochemical parameter, delta G0ad/Amin, where delta G0ad is the standard free energy of adsorption of the surfactant at the air/solution interface and Amin is the minimum cross sectional area of the surfactant, or the analogous parameter, delta 1sG0ad/1sAmin, at the solid/liquid interface, where the solid is an immobilized artificial membrane (IAM) that mimics a biological cell membrane. The general nature of the relationship between interfacial activity of surfactants and their biological effects in aquatic systems indicates that sorption to biological membranes is a critical parameter for predicting and understanding environmental effects. While specific interactions probably occur once a surfactant has penetrated a membrane bilayer, nonspecific hydrophobic interactions appear to be driving the sorption process.

Animals↗
PubMed2001

Cost-effectiveness of ambulatory laparoscopic cholecystectomy.

The merits of laparoscopic cholecystectomy include faster recovery, less postoperative pain, earlier return to work, and decreased cost. However, there are few economic data comparing laparoscopic cholecystectomy in an ambulatory versus overnight stay setting. In a 12-month period, 74 consecutive cholecystectomies were performed laparoscopically by one surgeon. The ambulatory group consisted of 36 patients who were discharged from the hospital the same day after a mean recovery time of 5 hours (range, 2.25-10.33). Of the remaining 38 patients, 19 were admitted after surgery on 23-hour observation status, and 19 were inpatients. The average hospital cost was significantly less in the ambulatory group than in the observation group, with an 11% mean reduction in cost per patient (P = 0.0061). No patient in either group was readmitted to the hospital within 30 days of surgery. Laparoscopic cholecystectomy can be performed safely in an outpatient setting. The cost savings of ambulatory care versus observation are clearly shown in this study.

Adult↗
PubMed2000

Intrinsic and extrinsic contributions to auditory selectivity in a song nucleus critical for vocal plasticity.

The development, maintenance, and perception of learned vocalizations in songbirds are likely to require auditory neurons that respond selectively to song. Neurons with song-selective responses have been described in several brain nuclei critical to singing, but the mechanisms by which such response properties arise, are modified, and propagate are poorly understood. The lateral magnocellular nucleus of the anterior neostriatum (LMAN) is the output of an anterior forebrain pathway (AFP) essential for learning and maintenance of song, processes dependent on auditory feedback. Although neurons throughout this pathway respond selectively to auditory presentation of the bird's own song, LMAN is the last stage at which responses to this auditory information could be transformed before being transmitted to vocal motor areas, where such responses may influence vocal production. Indeed, previous extracellular studies have indicated that LMAN's auditory selectivity is greater than that at earlier stages of the AFP. To determine whether LMAN local circuitry transforms or simply relays song-related auditory information to vocal control neurons, it is essential to distinguish local from extrinsic contributions to LMAN's auditory selectivity. In vivo intracellular recordings from LMAN projection neurons, coupled with local circuit inactivation, reveal that much of LMAN's song selectivity is supplied by its extrinsic inputs, but selective blockade of GABA receptors indicates that local inhibition is required for the expression of song selectivity. Therefore, LMAN neurons receive highly song-selective information, but LMAN's local circuitry can mask these selective inputs, providing a mechanism for context-dependent auditory feedback.

Acoustic Stimulation↗
PubMed2000

Permanent declines in pulmonary function following pneumonia in human immunodeficiency virus-infected persons. The Pulmonary Complications of HIV Infection Study Group.

Human immunodeficiency virus (HIV)-associated respiratory infections, most notably Pneumocystis carinii pneumonia (PCP), but also bacterial pneumonia (BP), result in reductions in lung function that have been studied mainly during the course of acute infection. Whether HIV-associated pneumonias also cause permanent changes in pulmonary function is unknown. In this study we investigated the long-term effects of PCP and BP on pulmonary function in a cohort of HIV-infected persons. One thousand, one hundred forty-nine HIV-infected persons were followed in a prospective, observational cohort study at six centers in the United States. Study participants had pulmonary function testing performed at regular preset intervals. PCP and BP diagnoses were verified with defined criteria. Longitudinal multivariate analysis was used to model pulmonary function in terms of demographic data and occurrence of PCP or BP. We found that PCP or BP was associated with permanent decreases in FEV(1), FVC, FEV(1)/FVC, and the diffusing capacity of carbon monoxide. Neither infection resulted in statistically significant changes in TLC. We conclude that PCP and BP result in expiratory airflow reductions that persist after the acute infection resolves. The clinical implications of these changes are unknown, but they may contribute to prolonged respiratory complaints in HIV-infected patients who have had pneumonia.

AIDS-Related Opportunistic Infections↗
PubMed1999

Role of bronchoscopy in AIDS.

The differential diagnosis of pulmonary disorders in the HIV-infected individual is broad. Clinical features and chest radiographs may point towards a diagnosis but cannot reliably establish one. It is important to know the conditions in which bronchoscopy, BAL, and TBB are likely to be diagnostic, just as it is to know when other invasive or noninvasive procedures may be more useful. Finally, the incidence of transmission of infections such as tuberculosis during bronchoscopy and cross-contamination of patients with an improperly sterilized bronchoscope, cannot be overemphasized.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Regaining lost time: adult aging and the effect of time restoration on recall of time-compressed speech.

Two experiments in which time was restored to artificially accelerated (time-compressed) speech are reported. Experiment 1 showed that although both young and older adults' recall of the speech benefited from the restoration of time, time restoration failed to boost the older adults to their baseline levels for unaltered speech. In Experiment 2, either 100% or 125% of lost time was restored by inserting pauses, either at linguistic boundaries or at random points within the passages. Experiment 2 showed that the beneficial effects of time restoration depended on where processing time was inserted, as well as how much time was restored. Results are interpreted in terms of age-related slowing in speech processing moderated by preserved linguistic knowledge and short-term conceptual memory.

Adult↗
PubMed1999

Impact of bacterial pneumonia and Pneumocystis carinii pneumonia on human immunodeficiency virus disease progression. Pulmonary Complications of HIV Study Group.

The course of pneumonia caused by pyogenic bacteria and Pneumocystis carinii was examined in a multicity cohort study of HIV infection. The median duration of survival among 150 individuals following initial bacterial pneumonia was 24 months, compared with 37 months among 299 human immunodeficiency virus (HIV)-infected control subjects matched by study site and CD4 lymphocyte count (P<.001). For 152 subjects with P. carinii pneumonia, median survival was 23 months, compared with 30 months for 280 matched control subjects (P = .002). Median durations of survival associated with the two types of pneumonia differed by only 47 days, despite a higher median CD4 lymphocyte count associated with bacterial pneumonia. These results suggest that both P. carinii pneumonia and bacterial pneumonia are associated with a significantly worse subsequent HIV disease course. The similarity of prognosis after one episode of bacterial pneumonia vs. an AIDS-defining opportunistic infection and the proportion of cases occurring in association with a CD4 lymphocyte count of >200 suggest that measures to prevent bacterial pneumonia should be emphasized.

AIDS-Related Opportunistic Infections↗
PubMed1999

Aspects of human factors engineering in home telemedicine and telerehabilitation systems.

Human factors engineering and system design are critical elements in the newly developing field of telerehabilitation. Telerehabilitation is the remote delivery of rehabilitative services such as monitoring, training, and long-term care of persons with disabilities using telecommunications technology. This paper describes projects at the Rehabilitation Engineering Research Center (RERC) on Telerehabilitation in the context of three conceptual models: telecounseling and training, telemonitoring and assessment, and teletherapy. Issues pertaining to human factors engineering design are identified, and ongoing challenges are discussed.

Biomedical Engineering↗
PubMed1999

Pneumococcal infections in HIV-infected adults.

Bacterial pneumonia, specifically pneumococcal infection, is a frequent cause of morbidity and mortality in persons infected with human immunodeficiency virus (HIV). It causes morbidity directly and possibly progression of HIV infection. The clinical presentation and response to therapy are usually similar to that of patients without HIV infection, although radiographic presentations may be atypical. There is a higher incidence of invasive disease and extrapulmonary disease, and mortality may be increased in HIV-infected patients. HIV infection impairs the host response to pneumococcus in a variety of ways. Colonization with Streptococcus pneumoniae may be prolonged for reasons that are incompletely understood. Concern about the rising prevalence of resistant pneumococcal strains is increasing, but the clinical relevance is uncertain. At least 90% of the strains that cause invasive disease are present in the 23-valent pneumococcal vaccine. The response to vaccination declines as immunodeficiency progresses; however, the potential benefit to responders is great and the risk is minimal. Therefore, this vaccine is recommended for all HIV-infected persons.

AIDS-Related Opportunistic Infections↗