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Biomedical subjects

D L Dunn

Publications and source records attributed to D L Dunn.

At least 109 records · Page 6Linked to original sources

Uncompensated hospital care payment and access for the uninsured: evidence from New Jersey.

OBJECTIVE: We assess the impacts of New Jersey's payment for hospital uncompensated care on access for the uninsured. DATA SOURCES: Uncompensated care charges and other data were obtained from audited reports maintained by the New Jersey State Department of Health. Other data sources include the AHA Annual Survey and the Bureau of Labor Statistics. The sample includes 80 of 88 acute care hospitals in the state for 1979 to 1987. STUDY DESIGN: This study used a pre- and postdesign to assess the impacts of the introduction of uncompensated care payment. Both descriptive and multivariate analyses were used. Key variables include hospital ownership and teaching characteristics; the labor force composition; and the level of government funding for public health insurance. PRINCIPAL FINDINGS: The overall level of uncompensated hospital care increased markedly in New Jersey during the period 1979 through 1987. However, this trend can be attributed to variables other than the new payment system, including increased demand for uncompensated care. The program did result in a more even distribution of uncompensated care across hospitals. The financial condition of hospitals providing the largest share of this care also improved, ensuring continued access. CONCLUSIONS: Funding of uncompensated care via hospital payment regulation did not increase its overall provision. However, improved access was achieved as opportunities for the uninsured to receive care were made more widely available.

Financial Management, Hospital↗

Gram-negative bacterial sepsis and sepsis syndrome.

Gram-negative bacterial sepsis and septic shock remain significant causes of morbidity and mortality in hospitalized patients. Recent investigation in this area has served to better define the host response to these and other types of infection, a constellation of signs and symptoms that has been termed sepsis syndrome. Recent studies indicate that the mortality associated with this latter disease process is approximately 40%, despite administration of antimicrobial agents, hemodynamic monitoring and fluid resuscitation, and metabolic support. For this reason, the pathophysiology of this process is undergoing intensive examination, and attempts are being made to employ several new types of treatment modalities as adjunctive therapy. Although the initial antiendotoxin antibody trials have not demonstrated the efficacy of these reagents, these studies have provided extremely valuable information regarding appropriate trial design, the current epidemiology of sepsis syndrome (particularly in relation to the ensuing morbidity and mortality), and the pathophysiology of the host septic response and have highlighted the need for rapid, precise diagnostic assays. A number of other intriguing reagents, including anti-TNF-alpha antibody preparations, IL-1ra, bacterial permeability-increasing protein, TNF-binding protein, polymyxin B hemoperfusion, and lipid A analogues also are undergoing experimental and clinical testing in an attempt to reduce the mortality of this lethal disease process.

Animals↗

Assessing the implementation of physician-payment reform.

BACKGROUND: The Medicare program fundamentally changed its system of payment for physicians' services in 1992. Controversy over the new Medicare fee schedule has focused on three issues: the adequacy of the conversion factor used to translate resource-based relative-value units into fees; the ability of the new payment system to capture differences in work between surgeons and physicians in other specialties; and the allocation of practice expenses across services. METHODS: Using a standard service in each specialty, we developed simulation methods to assess the implementation of physician-payment reform. With these methods we calculated the potential net income for each specialty, as generated by different payment scenarios, including the Medicare fee schedule. RESULTS: We found that Medicare's current monetary-conversion factor yields an unreasonably low level of income for most specialties. Furthermore, the Medicare fee schedule misallocates practice expenses; invasive services are reimbursed for more than actual expenses, and medical services are reimbursed for less. Thus, physicians continue to be paid more generously for invasive services. Finally, the Medicare fee schedule does recognize the wide differences in the intensity of work performed by physicians in various specialties. CONCLUSIONS: The misallocation of practice expenses in the Medicare fee schedule results in serious underpayment for medical services. We think it likely that physicians compensate by performing more lucrative services, such as diagnostic tests. Even if legislation is passed to deal with the misallocation of expenses, the current conversion factor still produces unreasonably low levels of payment overall, which could dissuade those considering a career in medicine from entering the field. Finally, the simulation method we developed can be used as a tool for fee negotiations.

Economics, Medical↗

The Resource-Based Relative Value Scale. Methods, results, and impacts for ophthalmology.

In January 1992, the Health Care Financing Administration implemented sweeping legislation that reformed the way Medicare pays for physicians' services. The cornerstone of the reform consists of a new fee schedule based on the Resource-Based Relative Value Scale. This article summarizes the methods and data used to derive the scale for ophthalmology. The results and impacts of the new Medicare payment rates for ophthalmology are also assessed. Using our methods and assumptions, ophthalmologists stand to lose 16% of their Medicare revenues under a fully implemented relative value-based fee schedule. Overall, the fees for performing evaluation and management services will increase, while those for most surgical procedures and diagnostic tests will decrease. Physicians' practice decisions and medical students' specialty choices could be affected. Ophthalmologists who perform work-intensive surgical procedures and spend the majority of their time in the operating room will continue to earn much higher incomes than those who do not.

Centers for Medicare and Medicaid Services, U.S.↗

Anti-endotoxin monoclonal antibodies protect by enhancing bacterial and endotoxin clearance.

In this study, we sought to determine the mechanism(s) by which a type-specific anti-lipopolysaccharide monoclonal antibody (an IgG directed against the O-antigen polysaccharide region of Salmonella minnesota lipopolysaccharide) and its F(ab')2 fragments protect during gram-negative bacterial peritonitis and endotoxemia in mice. During peritoneal infection, (1) IgG significantly decreased mortality, bacteremia, and endotoxemia at all time points compared with saline solution pretreatment and (2) F(ab')2 fragments reduced mortality at 24 hours but not thereafter, and had no effect on bacteremia but reduced endotoxemia compared with saline solution pretreatment. In the endotoxin model, IgG pretreatment significantly reduced mortality compared with saline solution pretreatment, while F(ab')2 fragments had no significant effect on mortality. No difference in endotoxemia was observed in mice that received IgG, F(ab')2 fragments, or saline solution pretreatment during endotoxemia. These results suggest that type-specific anti-lipopolysaccharide monoclonal antibodies protect by Fc-mediated clearance of both bacteria and endotoxin.

Animals↗

Treatment of recurrent cytomegalovirus disease in patients receiving solid organ transplants.

Tissue-invasive cytomegalovirus (TI-CMV) disease occurs commonly after solid organ transplantation and has been associated with increased allograft loss and patient mortality. Although ganciclovir has been demonstrated to be an effective form of treatment for TI-CMV disease, therapy may be followed by recurrence. The purpose of this study was to determine the impact of recurrent TI-CMV disease on patient and allograft survival. We studied 619 patients who underwent solid organ transplantation (535 kidney transplants [253 from living related donors and 282 from cadavers] and 84 combined cadaveric kidney-pancreas transplants) during a 3 1/2-year period. One hundred fourteen patients (18.4%) developed TI-CMV disease and were treated with a standardized regimen of intravenous ganciclovir for 14 to 21 days. Of the 114 patients in whom primary TI-CMV disease developed, 28 (24.6%) developed recurrent TI-CMV disease more than 30 days after the initial episode, and these patients were retreated with ganciclovir. Cure rates at 30 days were 98.9% in patients with primary TI-CMV disease and 100% in patients with recurrent TI-CMV disease. Patients who underwent cadaveric kidney or kidney-pancreas transplantation were more likely to develop recurrent TI-CMV disease than were recipients of kidney transplants from living related donors; antirejection therapy also was associated with a higher incidence of recurrent TI-CMV disease. Patients who developed TI-CMV disease exhibited lower rates of graft and patient survival at 3 years than patients without TI-CMV disease or with solely asymptomatic CMV infection, although recurrent TI-CMV disease did not appear to exacerbate morbidity or mortality. We conclude that recurrent episodes of TI-CMV disease do not appear to further adversely affect patient or graft survival in comparison with primary TI-CMV disease in ganciclovir-treated patients.

Acyclovir↗

Monoclonal antibodies for diagnosis and treatment.

One of the marvels of the host immune response is its response to antigenic foreign substances by manufacturing proteins that bind tenaciously to their targets. These proteins are antibodies or immunoglobulins produced in vast diversity during an individual's lifetime. By virtue of this process, the mammalian host possesses the innate ability to mount an initial response to antigens to which there has been no prior experience and to develop an even more effective response on reexposure to these same substances. This capacity to distinguish self from nonself is one of the most basic aspects of the cellular and humoral arms of the immune response and is one of the primary means by which the host combats infection caused by many different types of pathogens. In this context, antibodies have long been recognized as a critical component of host defenses and are capable of binding to invading microbes and microbial toxins.

Antibodies, Monoclonal↗

Anti-lipopolysaccharide monoclonal antibodies inhibit macrophage TNF messenger RNA synthesis in vitro.

Gram-negative bacterial lipopolysaccharide (LPS, endotoxin) directly stimulates macrophages to produce tumor necrosis factor (TNF). TNF, in turn, produces a constellation of adverse effects that includes hypotension, systemic acidosis, arterial hypoxemia, and death. Transcription of the TNF gene occurs within minutes of LPS stimulation and appears to be a critical control point in the synthesis and secretion of TNF protein by macrophages. We hypothesized that murine monoclonal antibody (mAb) 8G9 directed against Escherichia coli 0111:B4 LPS would provide protective capacity against an E. coli 0111:B4 bacterial challenge in vivo and would concurrently inhibit LPS-induced synthesis of TNF mRNA and secretion of TNF protein in vitro. E. coli 0111:B4 LPS was used to stimulate a macrophage-derived cell line (RAW 264.7) to produce TNF in the presence or absence of mAb 8G9. Media alone and LPS without 8G9 mAb served as controls against which the effect of 8G9 mAb was compared. Total cellular RNA was purified and analyzed by a Northern blotting technique utilizing a radiolabeled cDNA probe specific for TNF mRNA. TNF mRNA levels from each sample were quantitated by autoradiograph densitometry. Pretreatment with mAb 8G9 provided protective capacity against an intraperitoneal E. coli 0111:B4 bacterial challenge in vivo when compared with saline pretreatment alone (22% versus 90% mortality respectively, P < 0.05). Preincubation of LPS with mAb 8G9 resulted in a significant inhibition of LPS-induced TNF mRNA synthesis (63 +/- 20%, P < 0.01) and TNF protein secretion (88 +/- 10%, P < 0.001) in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Relevance of tumor necrosis factor to graft-versus-host disease after small bowel transplantation.

The small bowel (SB), an organ replete with lymphocytes, may provoke graft-versus-host disease (GVHD) after transplantation (Tx). Since tumor necrosis factor (TNF) has been suspected of mediating the tissue lesions of GVHD, we sought to determine whether TNF could be detected in the serum of rats undergoing GVHD after SBTx or lymphocyte transfer. For this purpose, postoperative serum TNF activity was determined in Lewis x Brown Norway (LBNF1) hybrid rats suffering from GVHD after undergoing transplantation of an entire (group 1; n = 8) or a segmental (group 2; n = 4) Lew SB, or after i.p. injection with lethal doses (500 x 10(6)) of Lew lymphocytes (group 3; n = 3). Control LBNF1 received i.p. small doses (50 x 10(6)) of Lew lymphocytes (group 4; n = 4). Serum TNF activity was assessed using the WEHI bioassay. In rats with acute and lethal GVHD after entire SBTx (group 1) or injection with large doses of lymphocytes (group 3), TNF activity gradually increased and reached high levels by the time the rats were agonal. In segmental SBTx rats (group 2), GVHD was less severe than in entire SBTx rats. Similarly, the increase in TNF activity was less intense and only transient since it had returned to control levels by the time the rats had completely recovered from GVHD. In control rats primed with small doses of lymphocytes (group 4), GVHD did not occur and no increase in TNF activity was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Use of novel therapeutic agents for the treatment of serious infection.

The use of biologic reagents directed against invading microbes and deleterious aspects of the host response is presently under intense investigation. The development and use of these reagents have contributed significantly to our understanding of the host response to infection, and they probably represent the first true foray into the area of immunotherapeutic manipulation. Thus, the effects of the administration of anti-endotoxin and antitumor necrosis factor-alpha monoclonal antibodies and the interleukin-1 receptor antagonist are being examined in large-scale clinical trials, and tumor necrosis factor-binding protein and bactericidal/permeability-increasing protein also may undergo clinical testing. Much controversy has already arisen regarding the manner in which these therapeutic reagents will be best utilized. The enormous amount of information that has already been obtained concerning the use of these reagents assuredly will contribute significantly to our understanding of the diagnosis and treatment of serious infection and will set the stage for the development and appropriate testing of additional new diagnostic and therapeutic reagents during the current decade.

Animals↗

Evolution of kidney, pancreas, and islet transplantation for patients with diabetes at the University of Minnesota.

Transplantation began at the University of Minnesota in 1963. Treatment of diabetes and its complications has been emphasized since 1966, when the first pancreas-kidney transplant was done. Of 3,640 kidneys transplanted by 1992, 1,373 were for diabetic recipients, including 658 from living donors and 715 from cadaver donors. The results progressively improved; since 1984, survival rates of kidney grafts have been similar for diabetic and nondiabetic recipients, with three fourths of the grafts functioning at 4 years. As of 1992, 501 pancreas transplants had been done, including 170 simultaneous with a kidney, 142 after a kidney, and 188 alone for nonuremic diabetic patients; again, the results have improved: by the 1990s, graft survival rates were similar in the 3 recipient categories. Successful pancreas transplants have been shown by our coworkers to stabilize or improve neuropathy and prevent recurrence of diabetic nephropathy in kidney grafts. In an attempt to simplify endocrine replacement therapy, we have done 63 human islet transplants, 34 as allografts for patients with type I diabetes and 29 as autografts after total pancreatectomy to treat chronic pancreatitis. Insulin independence occurs for about 50% of islet autograft recipients. Two recent islet allograft recipients treated with 15-deoxyspergualin have had sustained insulin independence. We anticipate that endocrine replacement therapy by transplantation will become routine for diabetic patients as methods to prevent rejection are refined.

Diabetes Mellitus, Type 1↗