Down-regulation of CD55 and CD46 expression by anti-sense phosphorothioate oligonucleotides (S-ODNs) sensitizes tumour cells to complement attack.

Overexpression of one or more membrane-bound complement regulatory proteins (mCRPs) protects tumour cells against complement-mediated clearance by the autologous humoral immune response and is also considered as a barrier for successful immunotherapy with monoclonal anti-tumour antibodies. Neutralization of mCRPs by blocking antibodies, enzymatic removal or cytokine-mediated down-regulation has been shown to sensitize tumour cells to complement attack. In our study we applied, for the first time, anti-sense phosphorothioate oligonucleotides (S-ODNs) to knock down the expression of the mCRPs CD55 and CD46 with the aim of exploiting complement more effectively for tumour cell damage. Potent anti-sense oligonucleotides against CD55 and CD46 were identified by screening various target sequences (n = 10) for each regulator. S-ODN anti-CD55(687) reduced CD55 protein expression up to 84% and CD46 protein expression was inhibited up to 76% by S-ODN anti-CD46(85). Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed a similar reduction of the CD55 and CD46 mRNA levels, which argues for an RNAse H-dependent anti-sense mechanism. T47D, A549 and PC3 cells, representing breast, lung and prostate carcinoma, were used for functional studies. Dependent on the particular cell line, anti-sense-based inhibition of mCRP expression enhanced complement-dependent cytolysis (CDC) up to 42% for CD55 and up to 40% for CD46, and the combined inhibition of both regulators yielded further additive effects in T47D cells. C3 opsonization of CD55/CD46-deficient tumour cells was also clearly enhanced upon mCRP suppression. Due to the clinical applicability of S-ODNs, the anti-sense approach described in this study may offer an additional alternative to improve the efficacy of antibody- and complement-based cancer immunotherapy.

Obstacles to cancer immunotherapy: expression of membrane complement regulatory proteins (mCRPs) in tumors.

Monoclonal antibodies (mAbs) are being increasingly used in cancer therapy owing to their ability to recognize specifically cancer cells and to activate complement- and cell-mediated cytotoxicity and/or to induce growth arrest or apoptosis. The therapeutic potential of anticancer antibodies is significantly limited due to the ability of cancer cells to block killing by complement. Of the multiple resistance strategies exploited by cancer cells, the expression of membrane complement regulatory proteins (mCRPs), such as CD46 (membrane cofactor protein (MCP)), CD55 (decay-accelerating factor (DAF)), CD35 (complement receptor type-1 (CR1)) and CD59, has received most attention. CD46, CD55 and CD35 block the complement cascade at the C3 activation stage and CD59 prevents assembly of the membrane attack complex of complement (MAC). These proteins protect normal tissues from accidental injury by activated complement, but also confer resistance on cancer cells, thereby limiting the effect of complement-fixing monoclonal antibodies. Expression of mCRPs on malignant cells is highly variable, yet there is clear indication that certain tumors express higher mCRP levels than the normal tissue from which they have evolved. mCRP level of expression and cellular location may also vary during malignant transformation and between differentiated and undifferentiated tumors. Neutralizing anti-mCRP mAbs have been used in vitro to elucidate the significance of mCRP expression to the tumor complement resistance phenotype. In general, CD59 appears to be the most effective mCRP protecting tumor cells from complement-mediated lysis. Nevertheless, it acts additively, and in certain tumors even synergistically, with CD55 and CD46. It is envisaged that treatment of cancer patients with mCRP blocking antibodies targeted specifically to cancer cells in combination with anticancer complement-fixing antibodies will improve the therapeutic efficacy.

An evaluation of teaching methods utilized during an HIV miniresidency course for Thai physicians.

This study examines the efficacy of medical education methods in improving the knowledge base and clinical skills of participants attending a 2-day miniresidency course in HIV infection. Instructional methods included: a didactic lecture format, diagnostic algorithm presentation, color slide photographic demonstration, bedside teaching rounds, and "meet-the-professor" sessions. Questions to assess the various instructional formats were administered and teaching methods were evaluated. Fifty-seven Thai physicians, highly exposed to HIV patient care duties, completed both precourse and postcourse tests. Overall, significant improvement was noted in participant's final global test score. However, discrepancies existed among the efficacy of instructional methods. Recognizing physical signs of HIV infection, as taught by slide photographs, revealed a high baseline level of expertise. Statistically significant postcourse gains were made in physician's diagnostic decision-making ability and basic knowledge of HIV and AIDS taught respectively by the methods of a teaching algorithm and didactic lecture. Despite the latter, participation performed poorly regarding HIV case management. This observation may be related to test design and cultural differences but likely underscores the difficulty in imparting clinical HIV management skills to course participants over a short period of time. Future continuing medical education (CME) courses intended to enhance physician care for the HIV infected must strive to refine evaluation methods for assessing case management skills while exploring innovative instructional techniques when current methods are ineffective.

PIP: To improve the skills of Thai physicians in the ambulatory care of patients with HIV and AIDS, a 2-day miniresidency was designed and tested in Bangkok in 1994. Course content included a photographic demonstration, didactic presentations, diagnostic algorithms, bedside teaching rounds, and questions and answers. Of the 57 physicians who completed the 2-day training, 88% reported HIV patient care duties and 44% estimated that over 20 such patients were currently in their care. Before the course, the mean strength of agreement with the statement, "I feel that I need to know more about HIV disease," was 4.10 out of a maximum of 5.00. Pre-test scores (0-100) were 80.3 for recognition of the physical signs of HIV/AIDS, 67.1 for diagnostic decision making, 61.4 for basic knowledge, and 40.0 for case study management. Post-test scores were 84.0, 80.5, 79.7, and 45.2, respectively, with an overall knowledge gain of 11.2 points (17.9% increase). Despite improvements in knowledge base and diagnostic ability, case management skills remained unsatisfactory. The inherent complexity of the written case scenarios presented to physicians in the test may have masked gains achieved in clinical management skills. However, future courses intended to enhance physician care in this area should seek to refine methods for assessing case management skills and to identify innovative alternative instructional techniques.

Urgency of medical care. Contrasting perceptions of HIV-positive patients and physicians.

BACKGROUND: To assess the agreement between patients and physicians about the appropriate time to seek medical attention for symptom complexes commonly encountered in human immunodeficiency virus (HIV) disease, identifying potential suboptimal utilization of health care services. METHODS: A questionnaire consisting of 25 clinical problems commonly encountered in the ambulatory care of patients with HIV infection was developed to survey opinions regarding the most appropriate time to seek medical attention. Participants included 70 anonymous HIV-positive patients attending a health department's early intervention clinic and 104 physicians recruited at academic conferences in 1992. RESULTS: Clinically and statistically (P < .05 after Bonferroni correction) significant disagreement between physicians and HIV-positive patients regarding perceived urgency to seek medical care was found in 22 of the 49 possible responses. In seven of these scenarios, patients perceived greater urgency to seek care than physicians, especially for relatively discrete complaints, such as oral lesions, lymphadenopathy, and Kaposi's sarcoma. Conversely, in 15 scenarios, physicians were more concerned than patients, especially for serious complaints, such as those associated with meningitis, retinitis, sinusitis, pneumonia, infectious diarrhea, and urinary tract infection. CONCLUSIONS: Substantial differences regarding the urgency to seek care exist between physicians and HIV-positive patients. Patients focused on the physical aspects of their disease and had difficulty appreciating important symptom complexes associated with serious but potentially reversible conditions. A need exists for health professionals to educate patients about the appropriate urgency to seek care for a number of common symptom complexes.

Treatment of mild hypertension. Decision before drugs.

The treatment of mild hypertension by the primary-care physician requires an understanding of its natural history and reflects a balance between patient observation and institution of drug therapy. The diagnosis of mild hypertension in the office is subject to pitfalls such as "white-coat" hypertension and pseudohypertension. For patients presenting with a diastolic blood pressure inconsistent with the presence of end-organ damage, ambulatory blood pressure monitoring may be of value. After a diagnosis of mild hypertension is established, institution of drug therapy is not an immediate issue in low-risk patients lacking end-organ damage. Mild hypertension tends to regress over time; therefore, nonpharmacologic measures of blood pressure reduction should be used first. Echocardiographic assessment of left ventricular mass is a noninvasive method to assess the severity of established cases and can guide decisions regarding aggressiveness of drug therapy. Because patients with mild hypertension make up a heterogeneous population, treatment goals need to be individualized. For patients with ischemic heart disease, reductions in the diastolic blood pressure below 85 mm Hg may produce adverse consequences. In persons suffering from diabetes, congestive heart failure, renal insufficiency, or showing increased left ventricular mass, the absolute reduction in blood pressure is guided by the clinical response of the coexisting disease. Finally, in patients with prior cerebrovascular disease, blood pressure should be lowered to the lowest tolerable level to achieve the maximum improvement in stroke reduction.

Influence of oral hygiene on elastase concentration of gingival crevicular fluid.

PMN elastase concentration of gingival crevicular fluid (GCF) was investigated in 11 healthy volunteers before professional tooth cleaning and after a 5-week period of intensive oral hygiene. GCF was collected using filter paper strips and the enzyme concentration was evaluated by the ELISA-technique. Intensive daily oral hygiene led to a considerable improvement in the clinical indices and to a reduction in the concentration of elastase in GCF. Despite the changes in the oral hygiene status, functional elastase was still present in the samples at the end of the experiment. This could mean that even at clinically healthy sites there is a lack of alpha-1-proteinase inhibitor, the major serum protein inactivating PMN elastase.

Hematologic toxicity of zidovudine in HIV-infected patients.

Zidovudine is now used extensively in an effort to control infection with the human immunodeficiency virus (HIV). The drug is associated with major hematologic toxicity, especially anemia and granulocytopenia. Conservative management of hematologic toxicity includes dosage reduction or cessation of therapy, diagnosis and treatment of chronic debilitating diseases, and supportive care, such as blood transfusions. New investigational agents, including hematopoietic growth factors, are being studied to combat the toxicities associated with zidovudine. The efficacy of these agents has yet to be established. Recent advances in drug efficacy at reduced dosage and in combination therapy promise to permit use of zidovudine with markedly reduced toxicity.

Evaluation of allopurinol use in patients with gout.

The use of long-term allopurinol therapy in patients with gout was evaluated. A pharmacy computer printout was used to identify all outpatients for whom allopurinol had been prescribed during a six-month period in 1985 at a large Veterans Administration medical center. Medical records were reviewed to (1) classify patients as either having or not having definite indications for allopurinol treatment, (2) determine whether physicians had ordered roentgenographic and laboratory tests for presence of monosodium urate crystals, uric acid excretion, and renal function, and (3) identify gout-associated risk factors and disease entities that could cause hyperuricemia. A pharmacy record of all allopurinol and probenecid prescriptions for the six-month period was obtained, along with cost data. Of the 286 patients who received allopurinol, 32 received the drug for an indication that could not definitely be established as gout. Of the 254 remaining patients, only 45 (17.7%) had a definite indication for allopurinol use as defined by the pharmacy and therapeutics committee. Although pretreatment measurement of serum creatinine was common, only a few patients underwent joint aspiration, a 24-hour urine collection, or roentgenography of affected joints. Large proportions of the patients were found to have gout-associated risk factors. If the 209 patients without definite indications for allopurinol therapy had been treated with probenecid instead of allopurinol, the annual cost savings would have been about $3700. Most of the patients receiving allopurinol for gout could reasonably have been treated with a uricosuric agent such as probenecid at a lower cost. Generally, physicians did not use diagnostic tests optimally before prescribing allopurinol and did not attempt to modify risk factors for gout.

Acetazolamide and dexamethasone in the prevention of acute mountain sickness.

We randomly assigned 32 healthy backpackers to receive placebo, acetazolamide (250 mg twice a day), dexamethasone acetate (4 mg four times a day), or both drugs in combination to determine the drug efficacy in preventing acute mountain sickness (AMS) at altitudes of 3,650 to 4,050m (12,000 to 13,300 ft). The incidence of AMS was high but symptoms were generally mild. Combined drug therapy was superior to both placebo and single drug therapy in risk reduction. Using acetazolamide alone was moderately beneficial in preventing the occurrence of AMS, although minor side effects were frequent. The use of dexamethasone alone did not significantly reduce the AMS incidence, and discontinuing its use resulted in symptoms suggestive of adrenal insufficiency. For recreational backpackers, routine drug prophylaxis is not recommended, in view of the mild nature of this illness and the adverse effects of medications. The efficacy of combined acetazolamide-dexamethasone therapy warrants further investigation at higher altitudes, where AMS is more severe, and the dexamethasone should be withdrawn gradually to avoid a possible adrenal crisis.

Sternoclavicular bacterial arthritis.

Bacterial infection of the sternoclavicular joint is an unusual event, with cases being reported in those with diabetes mellitus, in intravenous drug abusers, and in patients afflicted with rheumatoid arthritis. A case of this unique infection occurred in a person not known to be at risk for septic arthritis. Our report shows the difficulty in diagnosing this disorder.

Survey of ulcer-recurrence risk factors associated with long-term cimetidine prescribing.

The appropriateness of long-term cimetidine prescribing was evaluated retrospectively in 243 outpatients. Criteria defining appropriate indications for the use of cimetidine for longer than eight weeks were established. Of the 243 patients surveyed, 115 (47 percent) were considered to be inappropriately receiving long-term cimetidine, either because they had never been objectively studied radiographically or endoscopically (23 percent) or had negative results before initiation of therapy (24 percent). Risk factors known to be associated with recurrent peptic ulcer disease were reviewed. Patients fulfilling criteria for appropriate long-term cimetidine usage had a greater prevalence of risk factors compared to the nonjustifiable group. Of particular interest, individuals considered appropriate for long-term therapy were very likely to have had a gastrointestinal bleeding episode prior to beginning therapy (52 percent for gastric ulcer, 8 percent for the nonjustifiable group). This increased prevalence of gastrointestinal hemorrhage may be due to the inherent nature of peptic ulcer disease or a result of physicians selecting affected individuals who may benefit from long-term treatment. Eliminating inappropriate usage of long-term cimetidine in conjunction with a thorough evaluation of risk factors for recurrent ulcer disease can be useful in selecting those individuals most likely to benefit from long-term cimetidine therapy.

Alveolar hemorrhage associated with a membranoproliferative glomerulonephritis and smooth muscle antibody.

Alveolar hemorrhage along with glomerulonephritis developed in a 31-year-old black man. Renal biopsy demonstrated a granular pattern of immunofluorescence along basement membrane glomeruli, suggesting an immunologically mediated illness; however, light microscopy revealed a pure membranoproliferative glomerulonephritis, which has not been described to date in association with the alveolar hemorrhage syndromes. The patient's immunologic profile revealed a positive antinuclear antibody titer along with the presence of smooth muscle antibodies.

Rational approach to long-term use of H2-antagonists.

Although the approved indications for long-term histamine (H2) receptor-antagonists are limited to the management of hypersecretory states and prophylaxis against recurrent duodenal ulcer, these agents are often prescribed indiscriminately. Definitive guidelines concerning proper patient selection for prophylaxis against duodenal ulcer recurrence are lacking. Persons likely to benefit from maintenance therapy include those who smoke and those with a long duration of symptoms or prior history of an ulcer complication. Although not an approved indication, maintenance therapy to prevent recurrent gastric ulcer is appropriate for elderly persons receiving nonsteroidal anti-inflammatory drugs or in patients with poor cardiopulmonary status who may not tolerate surgery for an ulcer-related complication. The role of long-term H2-antagonist therapy in reflux esophagitis is not defined but may be appropriate in scleroderma and Barrett's esophagus. Finally, several miscellaneous conditions, including cystic fibrosis, Menetrier's disease, and pancreatic exocrine insufficiency, may benefit from long-term H2-antagonist therapy. Currently, clinical trials document the efficacy of maintenance therapy in duodenal ulcer for up to a three-year period; however, for gastric ulcer and chronic reflux esophagitis, the duration and benefit of long-term therapy is not established, and treatment regimens need to be individualized. Therapy may be required indefinitely in the miscellaneous states mentioned previously.

Severe exposure hypothermia: a resuscitation protocol.

Although hypothermia has been described as an emergency in suspended animation, severe degrees of hypothermia mandate appropriate aggressive intervention. Because of cardiac instability with core temperature below 28 C, aggressive invasive rewarming by F-F partial bypass is often ideal in this setting. In contrast, a gentle approach in other therapeutic maneuvers is equally important to prevent iatrogenic induction of VF in nonarrested victims. If the only definite criterion for diagnosis of death in hypothermia is failure to respond to resuscitation and rewarming, successful resuscitation must carefully balance aggressive and gentle interventions. Because CPR protocols involve legal as well as medical questions, additional prospective data are especially critical for resolving controversies in the initial management of profound exposure hypothermia.