Predictors of resource utilization for hospitalized patients with Pneumocystis carinii pneumonia (PCP): a summary of effects from the multi-city study of quality of PCP care

To determine whether patient and hospital characteristics were significantly associated with variations in Pneumocystis carinii (PCP) care and outcomes, we analyzed the use of diagnostic tests, intensive care units (ICUs), anti-PCP medications for persons hospitalized with human immunodeficiency virus (HIV)-related PCP, and hospital discharge status. We conducted retrospective chart reviews of a cohort of 2,174 patients with PCP hospitalized in 1987-1990. Outcomes included process of care for PCP and in-hospital mortality rates. Persons with PCP who were more severely ill at admission were more likely to have early medical care, to receive care in an intensive care unit, and to die in hospital. After we adjusted for differences in this severity of illness, we noted that Medicaid patients, injection drug users (IDUs), and patients treated at VA or county hospitals were significantly less likely than others to have diagnostic bronchoscopies and that persons covered by Medicaid, with a previous diagnosis of acquired immunodeficiency syndrome (AIDS), who did not receive prior zidovudine (AZT) or who received care in a VA hospital had the highest chances of in-hospital death. Insurance and risk group characteristics, severity of illness, and hospital characteristics appear to be the most important determinants of the intensity and timing of medical care and outcomes among patients hospitalized with PCP.

Tool use and team success in continuous quality improvement: are all tools created equal?

This article describes a study that used data from the Department of Veterans Affairs Health Services' Western Region TQI Registry to compare the relationship between theory tools, data tools, and perceived quality improvement. No significant bivariate relationship between the use of theory tools and perceived improvement was found, but there was a positive and significant relationship between the use of data tools and perceived improvement. The use of data management tools by all teams in the study was much lower than expected.

Relationship between procedures and health insurance for critically ill patients with Pneumocystis carinii pneumonia

The objective of the present study was to assess the association between type of health insurance coverage and use of diagnostic tests and therapies among patients with AIDS-related Pneumocystis carinii pneumonia (PCP). Fifty-six private, public, and community hospitals in Chicago, Los Angeles, and Miami were selected for the study, and the charts of 890 patients with empirically treated or cytologically confirmed PCP, hospitalized during 1987 to 1990 were retrospectively reviewed. Patients were classified by insurance status: self-pay (n = 56), Medicaid (n = 254), or private insurance, including health maintenance organizations and Medicare (n = 580). Primary outcomes were the use and timing of bronchoscopy, the type and timing of PCP therapy, and in-hospital mortality. The results indicate that Medicaid patients were less likely than privately insured patients to undergo bronchoscopy (relative odds = 0.61; 95% CI = 0.40, 0.93; p = 0.02) or to have their diagnosis of PCP confirmed (relative odds = 0.51; 95% CI = 0.33, 0.77), after adjusting for patient, severity of illness, and hospital characteristics. Medicaid patients were approximately three-fourths more likely than privately insured patients (relative odds = 1.73; 95% CI = 1.01, 2.96; p = 0.04) to die in-hospital, after adjusting for patient, severity of illness, and hospital characteristics. However, with further adjustment for confirmation of PCP, Medicaid patients no longer had a significantly higher likelihood of dying in-hospital. We conclude that Medicaid patients are less likely to receive diagnostic bronchoscopy than privately insured or self-insured patients, more likely to be empirically treated for PCP, and more likely to die in-hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Empirically treated Pneumocystis carinii pneumonia in Los Angeles, Chicago, and Miami: 1987-1990

Many patients infected with the human immunodeficiency virus (HIV) with symptoms suggestive of pneumonia are treated empirically for Pneumocystis carinii pneumonia (PCP), although other bacterial infections (e.g., tuberculosis) and pulmonary Kaposi's sarcoma may cause identical symptoms. Empiric treatment for PCP may result in misdiagnosis and mistreatment. When the outcomes of cytologically confirmed versus empirically treated PCP cases were evaluated, the most important predictors of in-hospital mortality were severity of illness and use of bronchoscopy. Persons who did not undergo bronchoscopy had higher mortality rates than patients negative by bronchoscopy or cytologically confirmed as positive for PCP (22% vs. 11% vs. 14%, P < .01), although severity of illness and timing of anti-PCP medications did not differ significantly. Compared with cytologically confirmed cases, persons who did not have bronchoscopy were more likely to die than were bronchoscopy-negative patients (P < .05), after adjusting for severity of illness. Bronchoscopy use may have contributed to better outcomes for persons treated for HIV-related PCP.

The learning curve for AIDS-related Pneumocystis carinii pneumonia: experience from 3,981 cases in Veterans Affairs Hospitals 1987-1991

Previous studies have found lower mortality rates for AIDS-related Pneumocystis carinii pneumonia (PCP) in hospitals with higher levels of experience with PCP. It is not known if patients are selectively referred to better hospitals or if there is a learning curve whereby outcomes improve as physicians gain experience in treating PCP. We assessed cases of PCP at 140 Veterans Administration (VA) Medical Centers in the United States. During 1987-1991, 3,981 patients were hospitalized with first-episode AIDS-related PCP. Mortality at 30 days after admission. For these 3,981 hospitalizations at the 140 study hospitals, the 30-day mortality was 19%. Logistic regression models indicate that older age, race, geographic area, earlier year of treatment, hospitalization in the previous 12 months, and lower levels of hospital experience with AIDS were significant predictors of mortality at 30 days after admission. Compared with hospitals that had treated three cases or fewer of first-episode PCP, the odds of mortality at 30 days at hospitals that treated > 50 cases of first-episode PCP were 0.73 (95% confidence interval 0.58-0.91), after controlling for differences in characteristics of the patients, year, and region. Mortality of patients with AIDS-related PCP decreases as VA hospitals gain experience. Longitudinal analyses over a 5-year period suggest that a learning curve best explains this finding.

A rapid preadmission method for predicting inpatient course of disease for patients with HIV-related Pneumocystis carinii pneumonia

Pneumocystis carinii pneumonia (PCP) has been the most common reason for hospitalization and the most common cause of death for persons with HIV infection. Hospital mortality rates for PCP range from 10 to 60%. Studies that evaluate differences in hospital mortality rates must control for differences in patient severity of illness. We developed a simple staging system for categorizing severity of illness in patients with PCP. We analyzed the relation between clinical factors and in-hospital mortality for 576 hospitalized patients with HIV-related PCP treated at 56 hospitals for the years 1987 to 1990. Four stages of PCP could be identified based on three routinely measured clinical variables: alveolar-arterial oxygen difference, total lymphocyte count, and body mass index. The mortality rate increased by stage: 1% for Stage 1, 8% for Stage 2, 23% for Stage 3, and 48% for Stage 4. The four-stage severity system compared well with previous models developed for AIDS and for PCP, and is easier to use in clinical practice. Our staging system identifies patients with a high and low risk of in-hospital death upon admission. Physicians may benefit from consideration of PCP stage in deciding on management strategies. In addition, researchers involved in clinical trials of new agents for PCP might consider stratification by PCP stage in order to define homogenous groups.

Free radicals enhance basal release of D-[3H]aspartate from cerebral cortical synaptosomes

Excessive generation of free radicals has been implicated in several pathological conditions. We demonstrated previously that peroxide-generated free radicals decrease calcium-dependent high K(+)-evoked L[3H]-glutamate release from synaptosomes while increasing calcium-independent basal release. The present study evaluates the nonvesicular release of excitatory amino acid neurotransmitters, using D-[3H]aspartate as an exogenous label of the cytoplasmic pool of L-glutamate and L-aspartate. Isolated presynaptic nerve terminals from the guinea pig cerebral cortex were used to examine the actions and interactions of peroxide, iron, and desferrioxamine. Pretreatment with peroxide, iron alone, or peroxide with iron significantly increased the calcium-independent basal release of D-[3H]aspartate. Pretreatment with desferrioxamine had little effect on its own but significantly limited the enhancement by peroxide. High K(+)-evoked release in the presence of Ca2+ was enhanced by peroxide but not by iron. These data suggest that peroxide increases nonvesicular basal release of excitatory amino acids through Fenton-generated hydroxyl radicals. This release could cause accumulation of extracellular excitatory amino acids and contribute to the excitotoxicity associated with some pathologies.

Modification of monoclonal antibody carbohydrates by oxidation, conjugation, or deoxymannojirimycin does not interfere with antibody effector functions

Site-specific attachment of metal chelators or cytotoxic agents to the carbohydrate region of monoclonal antibodies results in clinically useful immunoconjugates [Doerr et al. (1991) Ann Surg 214: 118, Wynant et al. (1991) Prostate 18: 229]. Since the capacity of monoclonal antibodies (mAb) to mediate tumor cell lysis via antibody-dependent cellular cytotoxicity (ADCC) or complement-dependent cytotoxicity (CDC) may accentuate the therapeutic effectiveness of immunoconjugates, we determined whether site-specific modification of mAb carbohydrates interfered with these functions. The chemical modifications examined consisted of periodate oxidation and subsequent conjugation to either a peptide linker/chelator (GYK-DTPA) or a cytotoxic drug (doxorubicin adipic dihydrazide). mAb-associated carbohydrates were also modified metabolically by incubating hybridoma cells in the presence of a glucosidase inhibitor deoxymannojirimycin to produce high-mannose antibody. All four forms (unaltered, oxidized, conjugated and high-mannose) of murine mAb OVB-3 mediated tumor cell lysis via CDC. Similarly, equivalent ADCC was observed with native and conjugated forms of mAb OVB-3 and EGFR.1. ADCC was achieved with different murine effector cells such as naive (NS), poly (I*C)- and lipopolysaccharide-stimulated (SS) spleen cells, or Corynebacterium-parvum-elicited peritoneal cells (PEC). All murine effector cell types mediated tumor cell lysis but differed in potency such that PEC > SS > NS. Excellent ADCC activity was also demonstrable by human peripheral blood mononuclear cells with OVB-3-GYK-DTPA and high-mannose OVB-3 mAb. ADCC activity was detectable in vivo: both native and conjugated OVB-3 inhibited growth of OVCAR-3 xenografts in nude mice primed with C. parvum. In conclusion, modification of mAb carbohydrates did not compromise their in vivo or in vitro biological functions. Therefore, combination therapy using immunomodulators to enhance the effector functions of site-specific immunoconjugates could be seriously contemplated.

Improved outcomes in intensive care units for AIDS-related Pneumocystis carinii pneumonia: 1987-1991

Respiratory failure due to Pneumocystis carinii pneumonia (PCP) is the most common complication requiring an intensive care unit (ICU) for persons with AIDS. In this study, we evaluated patterns of ICU use for ICU patients with first-episode PCP in 15 Veterans Administration Medical Centers from 1987 to 1991. Twelve percent of all patients with PCP received care in the ICU. The survival rates improved steadily during these years. Although there was little variation in the relative frequency of ICU use, the effectiveness of ICU use appeared to improve over time. In the more recent years, relatively more survivors and relatively fewer nonsurvivors received care in an ICU. Changes in medical practice such as adjunctive use of steroids for severe cases of PCP and more effective use of scarce resources may account for the improved survival rates for patients with PCP who are treated in an ICU.

Effect of oxidative stress on excitatory amino acid release by cerebral cortical synaptosomes

Previous studies in our laboratory have suggested that an oxidation reaction is responsible for the actions of free radicals to decrease synaptic potentials. Recently we observed that free radicals both decreased depolarization-induced vesicular release and enhanced basal, nonvesicular release of the excitatory amino acid, [3H]L-glutamate. In order to evaluate the contribution of oxidative reactions to this latter effect, we evaluated the actions of the oxidizing agent chloramine-T on synaptosomal release of excitatory amino acids, using [3H]D-aspartate as the exogenous label. Basal and depolarization evoked [3H]D-aspartate release were calcium-independent and nonvesicular. Chloramine-T pretreatment significantly increased basal release, while having no effect on high K(+)-evoked release. These data suggest that an oxidative process can mimic the free radical increase of basal release, as well as the decrease in synaptic potentials. On the other hand, the calcium-independent-evoked release may involve a different mechanism. Our results demonstrate that under basal, nondepolarizing conditions, oxidative stress exerts an adverse effect on the presynaptic nerve terminal, resulting in an increased release of potentially damaging excitatory amino acid neurotransmitters.

Use of traditional and modern health services by Laotian refugees

Although refugee health care emerged as a special interest in the United States following the influx of almost a million Southeast Asians since 1975, few studies have been done of the influence of refugee traditions on the use of Western medical services. The illness patterns, medical beliefs, and health care behavior of a Southeast Asian refugee group, the Mien from Laos are described in this study. A cohort of 119 Mien refugees living in Richmond, California, was observed for a 6-month period. In-home interviews were undertaken about all episodes of ill health, including treatment and health care decisions. This study shows that the Mien integrate traditional healing beliefs and practices with the use of American health services. Such findings are important because the increasing cultural diversity in the United States, particularly in Western states, necessitates that health care professionals understand the importance of cultural factors for access to and the use of health care by all patients including refugees and other immigrant groups.

Peroxide effects on [3H]l-glutamate release by synaptosomes isolated from the cerebral cortex

Basal (non-depolarized) and high K(+)-stimulated [3H]L-glutamate release in the presence and absence of Ca2+ were assessed using presynaptic nerve terminals (synaptosomes) isolated from the cerebral cortex of the guinea pig. Basal glutamate release was found to be Ca(2+)-independent and was significantly increased following treatment with hydrogen peroxide (H2O2). On the other hand, depolarization-induced release had both a Ca(2+)-dependent and Ca(2+)-independent component. Both components of stimulated release were suppressed by H2O2. In fact, Ca(2+)-dependent evoked release was virtually eliminated by H2O2 pretreatment. The data suggest that H2O2 exerts a differential effect on the neurochemical mechanisms involved in basal and stimulated glutamate release at the presynaptic nerve terminal.

Interaction studies of tilomisole, aspirin, and naproxen in acute and chronic inflammation with assessment of gastrointestinal irritancy in the rat

The effect of combination NSAID therapy of tilomisole with aspirin or naproxen was studied in rats with carrageenan-induced paw edema and established adjuvant arthritis. Inflamed paws were measured using mercury plethysmography and the arthritic paws were X-rayed to determine any bony/soft tissue changes. The gastrointestinal tract was also examined for bleeding and ulceration. Tilomisole had a less potent acute anti-inflammatory effect than aspirin or naproxen, but produced no significant gastrointestinal damage. A significant reduction in anti-inflammatory activity was observed with the tilomisole/aspirin combination in acute inflammation. Only additive interactions were observed with the naproxen inhibition. In the established arthritis assay, a significant synergistic anti-inflammatory response, i.e. both inhibition of paw edema and bone erosion, was also observed with the 80 and 93% tilomisole/naproxen combinations. The gastric ulcerogenic effect of the combination paralleled its increased activity. The synergism between tilomisole and naproxen in this chronic arthritic model may be due to enhanced cyclooxygenase inhibitory activity. These drug interaction studies suggest possible interactions in human clinical trials of rheumatoid arthritis.

Frequent anti-V-region immune response to mouse B72.3 monoclonal antibody

The immune response of 56 colorectal cancer patients to a single infusion of 1 mg of radiolabeled (111In) mouse B72.3-GYK-DTPA immunoconjugate was examined using a double-antigen radiometric assay system. The incidence of antibody response was 48% to polyclonal mouse IgG, 71% to mouse B72.3, and 62% to chimeric B72.3. Twelve patients (23%) had an antibody response to B72.3 V region in the absence of binding to polyclonal mouse IgG. An antiidiotype response was demonstrated in sera from 36% of 25 patients examined and correlated well with chimeric B72.3-GYK-DTPA immunoconjugate binding (r = 0.72, moderately well with mouse B72.3 binding (r = 0.56), and not at all with polyclonal mouse IgG binding (r = 0.28). The peak antibody response occurred most frequently 2 weeks postinfusion, although a "delayed" peak response to chimeric B72.2 occurred in 29% of patients. This study suggests that mouse B72.3 causes an immune response in the majority of patients and that antibody response to the V region is common. Understanding the physiological significance of these antibody responses will require correlation with the kinetics and tumor localization of repeat infusions of such immunoconjugates.

Immunohistochemical and pharmacokinetic characterization of site-specific immunoconjugate 15A8-glycyl-tyrosyl-(N-epsilon-diethylenetriamine pentaacetic acid)-lysine derived from anti-breast carcinoma monoclonal antibody 15A8

In this study, the breast carcinoma-reactive monoclonal antibody 15A8 and a site-specific immunoconjugate of the antibody, 15A8-glycyl-tyrosyl-(N-epsilon-diethylenetriamine pentaacetic acid)-lysine (15A8-GYK-DTPA), were characterized by immunohistological methods for reactivity with normal and neoplastic human tissues and normal cynomolgus monkey tissues. In addition, 15A8-GYK-DTPA labeled with 111In was assessed by in vivo imaging and pharmacokinetic studies for localization to human tumor xenografts in nude mice. The native antibody and the site-specific immunoconjugate exhibited similar limited reactivity with normal human tissues. Specifically, epithelial structures, including normal breast epithelium, lung alveoli, bronchial epithelium and glands, liver bile ducts, pancreatic ducts, kidney distal and collecting tubules, epidermal and esophageal epithelium, endometrial glands, and thymic Hassall's corpuscles, were reactive. Normal monkey tissues stained with 15A8 exhibited a similar pattern of reactivities. Antibody 15A8 reacted broadly with epithelium-derived tumors; more than 60% of the cells in all of the breast, colon, non-small cell lung, ovarian, prostate, bladder, and renal carcinomas tested expressed the antigen. In contrast, a variety of nonepithelial neoplasms, including lymphomas, melanomas, sarcomas, and small cell lung carcinomas, were nonreactive. 15A8-GYK-DTPA-111In administered i.v. rapidly localized to and imaged both MX-1 and MCF-7 human breast carcinoma xenografts in nude mice, reaching maximal levels of about 20% of injected dose/g of tumor within 4 days. No unusual localization to any nontumor tissue or organ was seen; the level of radioactivity in the normal tissues and organs was at or below that seen in the blood. Furthermore, the immunoconjugate did not accumulate in xenografts of the antigen-negative breast carcinoma ZR-75-1, which indicates that tumor localization was antigen specific. Pharmacokinetic studies in cynomolgus monkeys suggested that significant amounts of 15A8-GYK-DTPA-111In did not localize to normal epithelia and demonstrated that the immunoconjugate was not toxic. These findings suggest that antibody 15A8 may be useful in the diagnosis and therapy of breast cancer and possibly other carcinomas.

Antitumor monoclonal antibodies generated by immunization with mucins

This report describes the development and characterization of monoclonal antibody EG2.3. Although produced from a fusion that used splenocytes from donor mice immune to bovine salivary mucin (BSM), EG2.3 bound selectively to a number of human tumor cell lines including colon adenocarcinoma LS174T. Therefore, EG2.3 was compared to B72.3, another mucin (TAG-72) binding monoclonal antibody that also binds to LS174T. Like B72.3, EG2.3 reacted with an epitope on TAG-72. However, these two MAbs differed in a number of ways. Treatment of mucin or TAG-72 with periodate did not reduce the binding of EG2.3 to either antigen. In contrast, B72.3 did not react with either periodate treated antigens. Removal of sialic acid from either BSM or TAG-72 compromised the reactivity of both EG2.3 and B72.3. It was concluded that the EG2.3 binding site was distinct from the carbohydrate structure detected by B72.3.

Interaction of Ca-channel blockers and high pressure at the crustacean neuromuscular junction

Exposure to high pressure causes a significant depression of synaptic transmission. We examined the effects of various Ca-channel blockers and their interaction with high pressure on excitatory neuromuscular junction currents (EJCs) of lobster abdominal muscles. Reduced [Ca2+]o to half of normal concentration or exposure to 40-60 microM CdCl2, 10-20 microM NiCl2 and 1 microM omega-conotoxin decreased EJCs by 50%. Nifedipine, Nitrendipine and Bay K-8644 were ineffective. Either Ca-blockers or reduced [Ca2+]o, enhanced EJC suppression exerted by high pressure. The data suggest that high pressure primarily affects Ca2+ inflow at the presynaptic terminals through N-type voltage-gated Ca-channel.

A 23187-stimulated calcium uptake and GABA release by cerebrocortical synaptosomes: effects of high pressure

Guinea pig cerebrocortical synaptosome preparations were used to study the effect of compression to 62 ATA on 45Ca2+ uptake and [3H]GABA release using a calcium ionophore A 23187, which bypasses the voltage-sensitive calcium channel. Pressure was found to exert a suppressive effect on the A 23187-induced release of [3H]GABA, while having no significant effect on A 23187-stimulated 45Ca2+ uptake. On the other hand, both depolarization-induced 45Ca2+ uptake and [3H]GABA release were inhibited by pressure exposure. These results suggest that pressure may suppress GABA release by affecting pre-synaptic events subsequent to calcium influx.

Immunohistochemical and pharmacokinetic characterization of the site-specific immunoconjugate CYT-356 derived from antiprostate monoclonal antibody 7E11-C5

In this study, a site-specific immunoconjugate, designated CYT-356, of the prostate-reactive monoclonal antibody 7E11-C5 was characterized by immunohistological methods for reactivity with normal and neoplastic human tissues. In addition, CYT-356 labeled with 111In was assessed by in vivo imaging and pharmacokinetic studies for localization to human tumor xenografts in nude mice. The native antibody and the site-specific immunoconjugate exhibited similar patterns of reactivity with normal human tissues. Although the majority of tissues tested were negative, weak reactivity with cardiac muscle, proximal kidney tubules, and sweat glands was observed. Positive staining of normal prostate epithelial cells and glandular lumina and strong reactivity with a subset of skeletal muscle cells were also observed. CYT-356 reacted with 100% of prostate tumors examined but was negative on a variety of other neoplasms. Following i.v. administration, CYT-356-111In rapidly localized to and imaged LNCaP human prostate adenocarcinoma xenografts in nude mice, reaching maximal levels of about 30% of injected dose/g of tumor within 3 days. No unusual localization was seen to any nontumor tissue or organ; the level of radioactivity in the normal tissues and organs was at or below that seen in the blood. The localization to xenografts was antigen specific and the accessible binding sites in 100-200-mg tumors appeared to be saturated at an antibody dose between 10 and 100 micrograms. These findings suggest that the CYT-356 immunoconjugate may be useful in the diagnosis and therapy of prostate cancer.

Characterization of interleukin 1 induced rabbit chondrocyte phospholipase A2

Stimulation of rabbit articular chondrocytes with interleukin 1 (IL-1) results in the activation of intracellular phospholipase A2 (PLA2) and the subsequent secretion of this enzyme into the extracellular milieu. Pretreatment of chondrocytes with actinomycin D or cycloheximide significantly inhibited IL-1 induced PLA2 activation and secretion, suggesting that the enzyme induction process is RNA and protein synthesis dependent. Chondrocyte PLA2 is highly calcium dependent with a 1 mM optimum CA++ concentration for hydrolytic activity; little or no hydrolysis is observed in the absence of calcium and the hydrolytic activity is abolished in the presence of 10 mM ethylenediamine tetraacetic acid. The enzyme is also pH sensitive with optimal PLA2 hydrolytic activity observed at pH 6.5-7. Further, chondrocyte PLA2 was sensitive to inhibition by mepacrine, a compound with PLA2 inhibitory activity. The IL-1 induced chondrocyte PLA2 has a molecular weight of approximately 10 kDa, as determined by molecular sieve G75 column chromatography. The apparent molecular weight and CA++, pH and drug sensitivity of the extracellular and intracellular forms of the IL-1 induced chondrocyte PLA2 are indistinguishable. Since this IL-1 induced enzyme has similar biochemical characteristics to PLA2 enzymes isolated from human rheumatoid and osteoarthritic synovial fluid, we suggest that the chondrocyte may be an important cellular source for this PLA2 enzymatic activity in inflamed joints.