Bruch's membrane and choroidal macrophages in early and advanced age-related macular degeneration

AIM

To determine the sub-macular Bruch's membrane (BrM) macrophage count and the choroidal and BrM macrophage immunophenotype in normal eyes and in eyes with early and advanced age-related macular degeneration (AMD).

METHODS

BrM macrophages were counted in 125 human eyes (normal, normal aged, early AMD and geographical atrophy), and CD68 and inducible nitric oxide synthase (iNOS) immunohistochemistry was performed on 16 human eyes (normal, normal aged, early AMD, geographical atrophy and disciform scarring). All eyes were examined clinically ante mortem. Results were correlated with histopathological features, including basal laminar deposit and membranous debris, and with clinical fundus appearance.

RESULTS

CD68(+) macrophages were found in the choroid of normal human eyes, and did not express iNOS. Expression of iNOS by choroidal macrophages (as well as endothelial cells and pericytes) was associated with: (1) recruitment of macrophages to BrM in early AMD eyes with soft drusen or thick continuous basal laminar deposit, corresponding to clinically detectable soft drusen or pigment changes; and (2) active disciform scarring. iNOS expression was absent in BrM macrophages, suggesting immunomodulatory differences between the choroid and BrM. The highest BrM macrophage counts were found in eyes with subclinical choroidal neovascularisation.

CONCLUSION

The presence of extracellular deposits (soft drusen and thick continuous basal laminar deposit) is associated with macrophage recruitment to BrM and alteration in the immunophenotype of resident choroidal macrophages.

Lung morphometry and collagen and elastin content: changes during normal development and after prenatal hormone exposure in sheep

This study examined whether the improvement in lung function after prenatal hormone exposure coincided with changes in lung morphometry or in collagen and elastin content. Fetal lambs received a single intramuscular injection of betamethasone (0.5 mg/kg) plus L-thyroxine (T4) (15 micrograms/kg) or vehicle control 48 h before delivery at 121, 128, or 135 d gestational age (d 121, d 128, d 135, term = 150 d). T4 was administered in conjunction with betamethasone in an attempt to enhance the maturational response. The right-upper lobes were instillation fixed at 30 cm H2O by Karnovsky's fixative after a 40-min period of mechanical ventilation. A number of significant changes occurred between d 121 and d 135 in control animals: alveolar airspace volume increased by 270%; despite a 40% reduction in alveolar septal thickness, alveolar septal volume did not change appreciably, suggesting a "redistribution" of septal tissue into the formation of secondary alveolar septa, which doubled in number; and both parenchymal collagen and elastin volume increased significantly, whereas pleural collagen and elastin volume did not change. In contrast to the changes seen in control animals, exposure to betamethasone plus T4 led to alveolar septal thinning at each gestational age without an associated increase in secondary septal number, a 40% decrease in alveolar septal volume, and a proportionate reduction in parenchymal elastin at d 121. Although attenuation of alveolar septa coincides with redistribution of septal tissue into the formation of secondary septa during normal maturation, exposure to betamethasone plus T4 promotes thinning of alveolar septa in the absence of secondary septal formation, which results in a loss of alveolar septal tissue.

Costs of hay fever in the United States in 1990

Hay fever, or allergic rhinitis, affects a significant proportion of the US population. The current analysis focuses on the question of estimating both the direct and indirect costs of hay fever in the US for 1990. The basic data used for this analysis derive from continuing national probability surveys of 1) the US civilian noninstitutionalized population and 2) patient visits to offices of nonfederal practicing physicians who are not in hospital-based specialties. The analysis is based on current methods of estimating the costs of illness. The two major components of the estimates are the direct costs of physician visits, diagnostic tests, and medications; and the indirect costs associated with work absences or other reduced productivity for those employed both in and outside the home. For the most part where data were unavailable or potentially unreliable, cost estimates were not imputed. As a result, these estimates should be considered to be biased downward. In spite of these relatively conservative assumptions, the estimates of annual illness costs for 1990 totalled $1.8 billion.

A study of gastroenterologists in the United States

A two-part study of gastroenterologists (GEs) was conducted. One component was the analysis of 1987 Part B Medicare Annual Data to assess volume of services and patterns of reimbursement to gastroenterologists. This study demonstrated that two-thirds of services billed by GEs are medical visits, whereas two-thirds of GEs' income is derived from endoscopies. Five endoscopies account for 50% of GEs' allowed charges. Correcting for case-mix and geographic location, GEs' charges for endoscopies are still 10% higher than other physicians performing the same procedures. The second component of the study was a survey of 379 members of three major gastroenterological associations. Demographic and practice characteristics are reported and compared, when possible, with other physician specialties. Respondents estimated they spent 52 h/wk in inpatient and outpatient activities, of which 17.5 h were spent performing endoscopies. Fewer than 50% of respondents billed for 31.4 h of professional activity each week. Medicare patients comprise 38.2% of their patients. Most physicians did not balance-bill, or balance-billed Medicare patients only when they were able to pay. Malpractice premiums have risen from $6,511 to $9,540 during the past 3 yr. Over 95% of respondents were able to correctly identify those conditions requiring upper gastrointestinal (UGI) endoscopy and colonoscopy.

Pharyngoesophageal perforation after blunt neck trauma

Pharyngoesophageal perforation secondary to blunt neck trauma is an uncommon injury that can cause serious morbidity and mortality if not recognized and treated. Pharyngeal perforation secondary to blunt trauma sustained while boxing is reported. Review of the world literature found 10 cases of pharyngoesophageal perforation secondary to blunt neck trauma. Analysis of these cases indicates that perforations less than 2 cm and limited to the pharynx may be treated medically with close observation. Large perforations and those perforations that extend to the esophageal inlet or involve the esophagus exclusively are best treated surgically.

Physician payment reform: anesthesiology as a case study

We examined the effects of Resource-based Relative Value Scale (RBRVS)- and physician diagnosis-related groups (MDDRG)-based payment for anesthesiology services related to surgery by simulating these physician payment reform options. We merged Medicare Part A (hospital) and Part B (anesthesiology) payment data for 7,770 patients for the MDDRG analysis and examined 10,431 surgical procedures for the RBRVS analysis within 27 diagnosis-related groups (DRGs) during the second half of 1986 in 16 hospitals representing different geographic regions, bed size, and teaching status. Assuming budget neutrality (i.e., constant total expenditure for anesthesiology services) and using the proposed methodologies, we simulated RBRVS and MDDRG payments and compared them to current payments for anesthesiology services. Individual surgical procedures demonstrated a two- to more than four-fold variation in duration, accompanied by a similar variation in anesthesiology payments. Within DRGs, there was a three- to ten-fold variation in duration, and a two- to seven-fold variation in anesthesiology payments. Anesthesiology time was highly correlated with surgical time (r = 0.86-0.96). Compared to the current system, RBRVS and MDDRG systems were associated with systematic variations in payments, such that on average, on each case, anesthesiologists practicing in rural and nonteaching hospitals would gain, whereas those in urban or suburban and teaching facilities would lose. After adjusting for complexity of procedure, the distribution of payment gains and losses was a function of duration of surgery, which is not influenced by the anethesiologist. Longer cases of a given surgical procedure result in payment decreases. The results document the importance of retaining a time factor in the payment methodology for anesthesiology services to maintain equitable payment across practice settings--an objective of physician payment reform.

Bilateral carotid body tumors managed with preoperative embolization: a case report and review

A patient with large bilateral carotid body tumors had preoperative, superselective embolization of major arterial afferent vessels. After marked reduction in tumor vascularity, total surgical extirpation was then possible without significant morbidity or carotid sacrifice. The use of preoperative embolization in the treatment of large bilateral lesions is emphasized and discussed.

Schwann cells cultured from adult rats contain a cytoskeletal protein related to astrocyte filaments

Cells that bound antibody to the astrocyte intermediate filament protein were cultured from adult rat sciatic nerve. The antigen was intracellular, finely filamentous, and formed perinuclear caps in response to colchicine, all properties of intermediate filaments. Cytoskeletal proteins of these cultures were separated by SDS-gel electrophoresis, transferred to nitrocellulose paper, and shown to bind the glial-specific antiserum to a protein of 50,000 daltons. All the cells that bound this serum had a Schwann cell surface antigen, Ran-1, whereas fibroblasts from the nerve had Thy-1 surface antigen and did not contain the astrocyte filament antigen. These results prove that some Schwann cells from adult nerve, in contrast to fibroblasts or immature Schwann cells, have an intermediate filament protein that shares antigenic determinants with, or may be identical to, the astrocyte filament protein.

Future research and policy directions in physician reimbursement

Payments to physicians absorb the second largest share of the health care dollar in the United States. In 1979, the share was 19 percent of the total, or $40.6 billion (Gibson, 1980). The Health Care Financing Administration (HCFA) alone spent $8.6 billion for physician services, representing approximately 16 percent of all public funds disbursed under HCFA programs. This paper presents an overview of various issues concerning physician reimbursement. Several major areas have been identified (access, cost, quality, and improving or refining the Office of Research, Demonstrations, and Statistics' [ORDS] research techniques for analyzing topics concerning physician reimbursement). Each area is introduced with a brief discussion of some of the problems associated with the physician reimbursement systems relating to that area. Selected results are then presented from the previous research in each area, along with descriptions of continuing studies currently underway. Each section concludes with a discussion of potential future directions for new research or data development.