Early experience with a novel plaque excision system for the treatment of complex coronary lesions.

The use of directional coronary atherectomy (DCA) in current practice has been limited. The SilverHawk System is a newly developed plaque excision device that aims to overcome the drawbacks of prior DCA platforms. The device was evaluated in a porcine coronary model and in a series of patients. Procedural variables along with outcomes were reviewed. Quantitative angiography (QCA) was performed and excised tissue fragments were weighed and examined histologically. In porcine cases, pretreatment MLD increased from 0.51 +/- 0.26 to 2.36 +/- 0.59 mm postdebulking and 19.9 +/- 7.6 mg of tissue was retrieved. In human cases, pretreatment MLD increased from 0.8 +/- 0.4 to 2.2 +/- 0.5 mm postdebulking and 15.2 +/- 7.8 mg of tissue was retrieved without complications. These data show that the SilverHawk System may offer significant utility in treating a wide variety of complex coronary lesions.     

Mental disorder among homeless persons in the United States: An overview of recent empirical literature

Reviewed literature on the homeless reports higher rates of psychiatric disorder, psychological distress, and previous psychiatric hospitalization compared to the general population. However, understandardized methodology and lack of consistent findings across studies prohibit reliable prevalence estimates of mental disorder among the homeless.Dr. Robertson is with the Center for Research of Women of Wellesley College, Wellesley, Massachusetts 02181.     

Computed tomography and plain radiography in experimental fracture healing

We evaluated the relative contribution of plain radiographs and computed tomography to the assessment of fracture healing under experimental circumstances. In 15 sheep, we performed midshaft femoral osteotomies and internal fixation of the resultant segmental fractures. Radiographs were obtained preoperatively and immediately postoperatively. Animals were sacrificed at 3 weeks, 6 weeks, 12 weeks, 24 weeks, and 36 weeks after surgery, and the femoral specimens radiographed. After removal of the internal fixation devices, computed tomographic scans of the specimens were performed.By 3 weeks, callus was visible, but at 6 weeks, a trabecular pattern in the callus was seen on plain films but not on computed tomography. There was progressive organization of the callus on both studies. At 24 weeks, computed tomography demonstrated fracture lines not seen due to overlying callus on plain films and also more accurately showed incomplete union. By 36 weeks, healing was essentially complete according to both modalities, although there still were small gaps in the callus detectable on computed tomography but not on plain films.Computed tomography may be of value in the evaluation of fractures of long bones in those cases in which clinical examination and plain radiographs fail to give adequate information as to the status of healing.     

Pulmonary diseases in patients infected with the human immunodeficiency virus in Zimbabwe, Central Africa

During the 11 month period up to 30 September 1987, 37 patients (26 male, 11 female, mean age 27 years) with respiratory symptoms who were human immunodeficiency virus (HIV) positive, were studied prospectively on 40 occasions to determine the cause of any pulmonary complications. HIV was heterosexually transmitted. Predominant symptoms were cough (89%), fever (89%), weight loss (83%), and dyspnoea (60%). Transnasal fibre-optic bronchoscopy (with bronchoalveolar lavage, bronchial brushings and transbronchial lung biopsies) was performed on 35 patients, twice on 3 patients. 'Tru-cut' lung biopsies were obtained from 2 patients who died before bronchoscopy. Pulmonary tuberculosis was the commonest disease, being found in one-third of the patients (12 of 37). Mycobacterium tuberculosis was cultured from 4; the remainder of the plates were contaminated. Pneumocystis carinii was present in 8 patients: as the sole pathogen in 3, with Streptococcus pneumoniae in 4, Staphylococcus aureus in 2, and one also had tuberculous lymphadenitis. Endobronchial Kaposi's sarcoma was seen in 6 of 7 patients with skin nodules. Bacterial pathogens isolated included Staph. aureus (5), S. pneumoniae (5), Klebsiella pneumoniae (2), Haemophilus influenzae (2), H. parainfluenzae (1) and Pseudomonas aeruginosa (1). Invading Aspergillus fumigatus was diagnosed by lung biopsy in one. No diagnosis was reached for 8 patients. It is concluded that in Central Africa pulmonary complications in AIDS patients are similar to those in Europe and North America but the incidence of different pathogens depends on the prevalence of pathogens in the community. M. tuberculosis is probably the commonest pathogen. This study has confirmed that P. carinii pneumonia does occur, but occurs less frequently.     

Long-term effects of cochlear implants in children.

OBJECTIVE: Since 1987, when the use of multichannel cochlear implants was initiated in children, candidacy has expanded; many thousands of children have received these devices, and results have revealed a wide range of performance. However, few long-term studies exist on a large population of these children. There have been concerns expressed that cochlear implant function might degrade over time, that devices and electrodes might migrate and extrude in the growing child, or that there might even be a deleterious effect of long-term stimulation of the cochlear nerve. The purpose of this study was to explore the long-term effects of implantation as a function of performance over time, reimplantation, and educational factors. STUDY DESIGN AND SETTING: We studied 81 children who received implants at a major academic medical center and were followed for 5 to 13 years. RESULTS: Results revealed significant gains in speech perception, use of oral language, and ability to function in a mainstream environment. There was no decrease in performance over time and no significant incidence of device or electrode migration or extrusion, and device failure did not cause a deterioration in long-term outcome. CONCLUSIONS: Multichannel cochlear implants in children provide perception, linguistic, and educational advantages, which are not adversely affected by long-term electrical stimulation.     

Interactions Between Cytomegalovirus, Human Herpesvirus-6, and the Recurrence of Hepatitis C After Liver Transplantation

Recurrence of hepatitis C (HCV) following liver transplantation is common. Herpesvirus reactivation following transplant may have an immunomodulatory effect resulting in increased HCV replication. We studied whether cytomegalovirus (CMV) and human herpesvirus-6 (HHV-6) may be associated with HCV recurrence and viral load after transplant. We prospectively followed 66 HCV liver-transplant recipients with serial viral load testing for CMV and HHV-6. Infection and viral load were correlated with the development of biopsy-proven HCV recurrence and HCV viral loads. Histologic recurrence of HCV occurred in 41/66 (62.1%) patients. In the primary analysis, CMV infection and disease, and HHV-6 infection were not associated with HCV recurrence. Peak CMV and HHV-6 viral loads were not significantly different in patients with and without recurrence. No correlation was observed between HCV viral loads at 1 and 3 months post-transplant and peak HHV-6 or CMV viral loads. In a subgroup analysis, HHV-6 infection was associated with the development of more severe recurrence (hepatitis and/or fibrosis score > or = 2) (p = 0.01). Also, fibrosis scores at last follow up were higher in patients with CMV disease (1.67 vs. 0.56; p = 0.016) and in patients with HHV-6 infection (1.18 vs. 0.55; p = 0.031). In conclusion, HHV-6 and CMV infection and viral load were not associated with increased overall rates of HCV recurrence or HCV viral load after liver transplantation but may be associated with more severe forms of recurrence.     

Immunomodulation of Delayed Hypersensitivity to Methylated Bovine Serum Albumin (MBSA) in Mice Using Subliminal and Normal Sensitization Procedures

Delayed hypersensitivity (DH) was induced in the footpads of mice sensitized to methylated bovine serum albumin (MBSA). The magnitude of this DH response increased with increasing sensitizing concentration of MBSA. Levamisole administered 1 hr prior to MBSA challenge stimulated the DH response and this was optimal using subliminal sensitizing concentrations of antigen. A number of antirheumatic agents, immunomodulators mediator antagonists and antiallergies were subsequently examined using the subliminal sensitizing concentration of MBSA. The same drugs were also evaluated using a normal sensitizing procedure. These studies indicate that the sensitizing concentration of antigen is critical in establishing whether a drug will stimulate or suppress a DH response.     

Survival of corneal endothelium in McCarey-Kaufman (M-K) medium subjected to agitation

Studies were made comparing the corneal endothelium of bisected human corneas; one half of each was mechanically agitated in McCarey-Kaufman (M-K) medium, while the other half remained static in M-K medium for an equal period of time. Scanning electron microscopic (SEM) analysis of the corneal endothelium suggested that the endothelium of the corneas undergoing agitation does not show deterioration in morphology when compared with the non-agitated group. This finding is significant as donor corneas are now being transported in greater numbers.