The molecular and clinical role of Tensin 1/2/3 in cancer

Tensin 1 was originally described as a focal adhesion adaptor protein, playing a role in extracellular matrix and cytoskeletal interactions. Three other Tensin proteins were subsequently discovered, and the family was grouped as Tensin. It is now recognized that these proteins interact with multiple cell signalling cascades that are implicated in tumorigenesis. To understand the role of Tensin 1-3 in neoplasia, current molecular evidence is categorized by the hallmarks of cancer model. Additionally, clinical data involving Tensin 1-3 are reviewed to investigate the correlation between cellular effects and clinical phenotype. Tensin proteins commonly interact with the tumour suppressor, DLC1. The ability of Tensin to promote tumour progression is directly correlated with DLC1 expression. Members of the Tensin family appear to have tumour subtype-dependent effects on oncogenesis; despite numerous data evidencing a tumour suppressor role for Tensin 2, association of Tensins 1-3 with an oncogenic role notably in colorectal carcinoma and pancreatic ductal adenocarcinoma is of potential clinical relevance. The complex interplay between these focal adhesion adaptor proteins and signalling pathways are discussed to provide an up to date review of their role in cancer biology.

Risk factors for post-ERCP pancreatitis: a prospective, multicenter study

BACKGROUND

Post-ERCP pancreatitis is poorly understood. The goal of this study was to comprehensively evaluate potential procedure- and patient-related risk factors for post-ERCP pancreatitis over a wide spectrum of centers.

METHODS

Consecutive ERCP procedures were prospectively studied at 11 centers (6 private, 5 university). Complications were assessed at 30 days by using established consensus criteria.

RESULTS

Pancreatitis occurred after 131 (6.7%) of 1963 consecutive ERCP procedures (mild 70, moderate 55, severe 6). By univariate analysis, 23 of 32 investigated variables were significant. Multivariate risk factors with adjusted odds ratios (OR) were prior ERCP-induced pancreatitis (OR 5.4), suspected sphincter of Oddi dysfunction (OR 2.6), female gender (OR 2.5), normal serum bilirubin (OR 1.9), absence of chronic pancreatitis (OR 1.9), biliary sphincter balloon dilation (OR 4.5), difficult cannulation (OR 3.4), pancreatic sphincterotomy (OR 3.1), and 1 or more injections of contrast into the pancreatic duct (OR 2.7). Small bile duct diameter, sphincter of Oddi manometry, biliary sphincterotomy, and lower ERCP case volume were not multivariate risk factors for pancreatitis, although endoscopists performing on average more than 2 ERCPs per week had significantly greater success at bile duct cannulation (96.5% versus 91.5%, p = 0.0001). Combinations of patient characteristics including female gender, normal serum bilirubin, recurrent abdominal pain, and previous post-ERCP pancreatitis placed patients at increasingly higher risk of pancreatitis, regardless of whether ERCP was diagnostic, manometric, or therapeutic.

CONCLUSIONS

Patient-related factors are as important as procedure-related factors in determining risk for post-ERCP pancreatitis. These data emphasize the importance of careful patient selection as well as choice of technique in the avoidance of post-ERCP pancreatitis.

A combination of a chemically modified doxycycline and a bisphosphonate synergistically inhibits endotoxin-induced periodontal breakdown in rats

BACKGROUND

Chemically modified non-antimicrobial tetracyclines (CMTs) have been shown to inhibit pathologically elevated collagenase (and other matrix metalloproteinase, MMP) activity and bone resorption in vivo and in vitro.

METHODS

In the current study, suboptimal doses of CMT-8 (a non-antimicrobial chemically modified doxycycline) and a bisphosphonate (clodronate, an anti-bone resorption compound) were administered daily, either as a single agent or as a combination therapy, to rats with experimental periodontitis induced by repeated injection of bacterial endotoxin (LPS) into the gingiva. At the end of the 1-week protocol, the gingival tissues were dissected, extracted, and the extracts analyzed for MMPs (collagenases and gelatinases) and for elastase, and the defleshed jaws were morphometrically analyzed for alveolar bone loss.

RESULTS

LPS injection significantly (P<0.001) increased alveolar bone loss and increased collagenase (MMP-8), gelatinase (MMP-9), and elastase activities. Treatment of the LPS-injected rats with suboptimal CMT-8 alone or suboptimal clodronate alone produced slight reductions in the tissue-destructive proteinases and no significant reductions in alveolar bone loss. However, a combination of suboptimal CMT-8 and clodronate "normalized" the pathologically elevated levels of MMPs, elastase, and alveolar bone loss, indicating synergistic inhibition of tissue breakdown in this animal model of periodontitis.

CONCLUSIONS

Combination of a CMT and a bisphosphonate may be a useful treatment to optimally suppress periodontal destruction and tooth loss and in other tissue-destructive inflammatory diseases such as arthritis.

Biodistribution of radiolabeled [(3)H] CMT-3 in rats

CMT-3 is a NON-ANTIMICROBIAL tetracycline (TC), chemically modified to enhance its collagenase-inhibitory property. This property is therapeutically useful in treating diseases such as periodontitis, cancer and arthritis. CMT-3 was labeled with tritium [(3)H] at Carbon 7. Four adult male Sprague-Dawley rats (350--400 g body weight) were gavaged once with a mixture of cold CMT-3 and [(3)H] CMT-3 (750 microCi). An additional four rats were gavaged for 2 days with cold CMT-3(15 mg/Kg/day) and on the third day the rats were gavaged with a mixture of cold and [(2)H] CMT-3 (750 microCi); and all 8 rats were placed in the metabolic cages. Blood samples were collected from the tail at multiple intervals from 1--14 hr after [(3)H] CMT-3 administration. At 14 hr, the rats were anesthetized, euthanized and various tissues including visceral organs were removed and weighed. The contents of GI tracts were emptied and added to the fecal pellets and weighed. The urine samples were collected and volume measured. Each tissue or organ was minced finely with scissors and 100 mg of tissue was digested in 1 ml of Tissue-solv (Packard Lab), for 4 hrs at 37 degrees C and each sample was diluted up to 10 ml of distilled water. A 100 microl aliquot was taken and diluted with an equal volume of glacial acetic acid, 10 ml of Atom-lite was added and counted for radioactivity in a liquid scintillation spectrometer. This biodistribution study revealed that over 14 hrs, 54% and 3% of [(3)H] CMT-3 were excreted in the feces and urine, respectively. The serum [(3)H] CMT-3 count reached its maximum value at about 12 hours. The tissues retained the CMTs as follow: muscle (23%); skin (2.41%); bone (1.72%); and the brain retained 0.21% of the label. The radioactive CMT-3 in the visceral organs is as follows: GI tract - its contents (8.9%); heart (0.41%), testis (0.41%); lungs >(0.16%); spleen (0.08%); liver (0.03%); kidneys > (0.02%).

The lipophilicity, pharmacokinetics, and cellular uptake of different chemically-modified tetracyclines (CMTs)

CMTs are analogs of tetracyclines, which are chemically modified to eliminate their antimicrobial efficacy but which retain their inhibitory activity against matrix metalloproteinases. These compounds have been found to inhibit connective tissue breakdown in animal models of diseases such as periodontitis, arthritis and cancer. Because CMTs exhibit different in vivo efficacy in these various models of disease, the current study compared their pharmacokinetics and other properties as follows: Adult male Sprague-Dawley rats were administered by oral gavage a single dose of 5mg of different CMTs suspended in 1 ml 2% carboxymethyl-cellulose, and blood samples were collected from 1-48 hours after dosing. The sera were extracted, then analyzed by HPLC using a C-18 reverse-phase column. The results showed that the peak concentrations (C(max)) in rat sera 1-12 hours after oral administration of CMTs -1, -2,-3, -4,-5,-6,-7,-8 and doxycycline were 5.5, 0.7, 4.6, 6.2, 0.8, 0.7, 9.0 (note: the 3 peaks detected for CMT-7 were combined), 15.0 and 0.9 microg/ml, respectively. Their in vivo half-lives (t(1/2)) were 11, 5, 22, 11, 32, 15, 37, 38, and 17 hours, respectively. Of the anticollagenase CMTs tested, CMT-8 showed the greatest C(max) and t(1/2)values, followed by CMTs-3, -1, -4, and perhaps -7; CMTs-2, -5, and -6 exhibited much lower levels in serum. The relative lipophilicities of the 8 CMTs and doxycycline were tested by examining their extractability in octanol. The results showed that CMT-2, -5, and -6 had the lowest partition coefficients using this organic solvent, while CMT-3 was the most lipophilic. The lipophilicity of the different CMTs was also positively correlated (r(2)=0.767, P<0.05) to peak serum concentrations (C(max)), but not to their serum half-lives (r(2)=0.25,P=0.49). This property of the different CMTs was also found to be positively correlated to their ability to enter into human whole blood cells in vitro (r2=0.95, P<0.001). Since CMT-8, as well as CMTs-3 and -1, consistently exhibited the greatest in vivo efficacy in animal models of tissue breakdown, this may reflect, at least in part, their favorable pharmacokinetics and tissue uptake.

Adjunctive treatment with subantimicrobial doses of doxycycline: effects on gingival fluid collagenase activity and attachment loss in adult periodontitis

OBJECTIVES

The therapeutic effects of doxycycline and other tetracyclines in the treatment of periodontitis involve, at least in part, mechanisms that are unrelated to their antimicrobial activity. Previous clinical studies have shown that doxycycline administered orally, at doses below those needed for antimicrobial efficacy, to human subjects with adult periodontitis resulted in significantly reduced collagenase activity in gingival crevicular fluid (GCF) and in extracts of inflamed gingival tissues. The purpose of the present study was to identify clinically effective dosing regimens using subantimicrobial dose doxycycline (SDD) as an adjunctive therapy in patients with adult periodontitis.

MATERIAL AND METHODS

A total of 75 adult men and women qualified for enrollment into the three-part, placebo-controlled, double-blind, parallel-group study. Patients were stratified based on repeatedly exhibiting pathologic levels of periodontal attachment (ALv) and GCF collagenase activity at several appointments prior to baseline. Patients were administered a scaling and prophylaxis, then 1 of 5 treatment schedules for 12 weeks (part I), followed by a 12-week period of no drug therapy (part II), a second scaling and prophylaxis, and 12 additional weeks of treatment (part III). Primary determinants of efficacy included reductions in GCF collagenase activity and changes in relative ALv.

RESULTS

66 patients completed the 1st 12 weeks (part I) of the 3-part, 36-week study; 51 patients completed the entire 36-week study. From baseline to week 12 (part I), treatment with specially formulated SDD capsules (20 mg) 2x daily (1 x every 12 h) for up to 12 weeks was shown to significantly reduce GCF collagenase activity and to improve ALv, effects not seen in patients treated with placebo. Continuous drug therapy over the 12-week treatment period was needed to maintain and maximize the reduction in GCF collagenase and the improvement in ALv. Improvements in periodontal disease parameters occurred without the emergence of doxycycline-resistant micro-organisms. In patients administered an "on-off-on" regimen of SDD over 36 weeks (parts I-III), essentially no attachment loss occurred in patients receiving the highest of these SDD regimens (20 mg 2x daily during part I and 20 mg 1 x daily in part III), whereas patients administered placebo capsules experienced a mean attachment loss of approximately 0.8 mm at the 24- and 36-week time periods.

CONCLUSIONS

Doxycycline administered at subantimicrobial doses led to improvements in disease parameters, with no apparent side effects, and appears to have significant potential as an oral adjunctive therapy in the long-term management of adult periodontitis.

Excessive matrix metalloproteinase activity in diabetes: inhibition by tetracycline analogues with zinc reactivity

Diabetes mellitus in rats is characterized by excessive activity of several matrix metalloproteinases (MMPs), notably collagenase(s) and gelatinase(s), in skin, gingiva, and other tissues. A number of tetracyclines (TCs), both antimicrobial compounds as well as chemically modified non-antimicrobial TC analogues (CMTs) are known to possess potent inhibitory activity against these enzymes. Three conventional antimicrobial TCs and six CMTs were used in this study. In vitro, doxycycline was shown to possess higher inhibitory capacity (i.e. lower IC(max)) against diabetic rat skin collagenase than either minocycline or tetracycline HCl. Addition of excess zinc partially reversed the proteinase inhibition by TCs. In vivo, using rats made diabetic with streptozotocin (STZ), oral administration of various TCs led to decreased weight loss and substantial reductions in the activity of both skin collagenase and skin gelatinase (primarily MMP-9, 92 kDa) without affecting blood glucose. Using an in vitro spectrophotometric technique, the Zn(++) reactivity of several CMTs was assessed and found to be positively related to the potency of these compounds as MMP inhibitors. One particular CMT (CMT-5, pyrazole analogue), which is neither antimicrobial nor capable of binding metal cations, did not inhibit the MMPs. TCs have potential utility in management of diabetic complications mediated by excessive activity of MMPs.

RSV infection in infants and young children. What's new in diagnosis, treatment, and prevention?

RSV is the most important respiratory pathogen in infants and young children. About 1% of primary RSV infections result in hospitalization. The virus is spread by large droplets of secretions or contact with contaminated secretions. Infants infected with RSV may demonstrate poor feeding, rhinorrhea, apnea, lethargy, wheezing, and respiratory distress. Diagnosis may be made by clinical signs and symptoms (especially those observed during epidemics), by chest radiographs showing hyperinflation, or by rapid antigen detection with immunofluorescence of nasopharyngeal aspirates. Risk factors for severe disease accompanied by complications include chronic heart disease, chronic lung disease, immunodeficiency, HIV, and prematurity. Immunity is incomplete and of short duration, and reinfection is common. Treatment remains supportive and consists of oxygen administration, hydration, and diligent monitoring. Use of corticosteroids, bronchodilators, antibiotics, and ribavirin is controversial and is dependent largely on physician preference. Use of ribavirin should be reserved for patients who have severe underlying conditions associated with increased mortality rates. Intravenous RSV Ig has been replaced by palivizumab, which is generally recommended for infants at high risk for severe RSV, including those with a history of prematurity and those with chronic lung disease.

A chemically modified nonantimicrobial tetracycline (CMT-8) inhibits gingival matrix metalloproteinases, periodontal breakdown, and extra-oral bone loss in ovariectomized rats

Estrogen deficiency in the postmenopausal (PM) female is the major cause of osteoporosis and may contribute to increased periodontal disease, including alveolar bone loss, seen in these women. In the current study, an animal model of PM osteoporosis, the OVX adult female rat, was studied to determine: (i) the relationship between periodontal breakdown and skeletal bone loss, and (ii) the effect of CMT-8 on gingival collagenase and bone loss. OVX rats were daily gavaged with CMT-8 (1, 2, or 5 mg/rat) for 28 or 90 days; non-OVX rats and those gavaged with vehicle alone served as controls. Elevated collagenase activity, assessed using [3H-methyl] collagen as substrate in the presence or absence of APMA, was seen in the gingiva of the OVX rats, and CMT-8 therapy suppressed this effect. Western blot revealed a similar pattern for MMP-8 and MMP-13 concentrations. The changes in the gingival collagenase activity paralleled changes in periodontal bone loss, which, in turn, reflected trabecular bone density changes. Preliminary studies on PM humans administered sub-antimicrobial tetracycline as a matrix metalloproteinase inhibitor are under way.

MMP-mediated events in diabetes

Both Type I and Type II diabetes mellitus (DM) have been associated with unusually aggressive periodontitis. Accordingly, rat models of both types of DM were used to study (i) mechanisms mediating this systemic/local interaction and (ii) new pharmacologic approaches involving a series of chemically modified tetracyclines (CMTs) that have lost their antimicrobial but retained their host-modulating (e.g., MMP-inhibitory) properties. In vitro experiments on tissues from Type I DM rats demonstrated that several of these CMTs were better matrix metalloproteinase (MMP) inhibitors than was antibacterial doxycycline (doxy), except for CMT-5, which, unlike the other MMP inhibitors, was found not to react with zinc. Data from in vivo studies on the same rat model generally supported the relative efficacy of these compounds: the CMTs and doxy were found to inhibit MMP activity, enzyme expression, and alveolar bone loss. To examine other long-term complications such as nephropathy and retinopathy, a Type II (ZDF) model of DM was studied. Treatment of these DM rats with CMT-8 produced a 37% (p < 0.05), 93% (p < 0.001), and 50% (p < 0.01) reduction in the incidence of cataract development, proteinuria, and tooth loss, respectively; whereas the doxy-treated ZDF rats showed little or no effect on these parameters. CMT treatment decreased mortality of the Type II ZDF diabetic animals, clearly indicating that CMTs, but not commercially available antibiotic tetracyclines (TCs), may have therapeutic applications for the long-term management of diabetes.

Same-day discharge after endoscopic biliary sphincterotomy: observations from a prospective multicenter complication study. The Multicenter Endoscopic Sphincterotomy (MESH) Study Group

BACKGROUND

Same-day discharge after endoscopic biliary sphincterotomy (ES) is a common clinical practice, but there have been few data to guide appropriate selection of patients. Using a prospective, multicenter database of complications, we examined outcomes after same-day discharge as it was practiced by a variety of endoscopists and evaluated the ability of a multivariate risk factor analysis to predict which patients would require readmission for complications.

METHODS

A 150-variable database was prospectively collected at time of ES, before discharge and again at 30 days in consecutive patients undergoing ES at 17 centers. Complications were defined by consensus criteria and included all specific adverse events directly or indirectly related to ES requiring more than 1 night of hospitalization.

RESULTS

Six hundred fourteen (26%) of 2347 patients undergoing ES were discharged on the same day as the procedure, ranging from none at 6 centers to about 50% at 2 centers. After initial observation and release, readmission to the hospital for complications occurred in 35 (5.7%) of 614 same-day discharge patients (20 pancreatitis and 15 other complications, 3 severe). Of the same-day discharge patients, readmission was required for 14 (12.2%) of 115 who had at least one independently significant multivariate risk factor for overall complications (suspected sphincter of Oddi dysfunction, cirrhosis, difficult bile duct cannulation, precut sphincterotomy, or combined percutaneous-endoscopic procedure) versus 21 (4.2%) of 499 without a risk factor (odds ratio 3.1: 95% confidence interval [1.6, 6.3], p < 0.001). Of complications presenting within 24 hours after ES, only 44% presented within the first 2 hours, but 79% presented within 6 hours.

CONCLUSIONS

Same-day discharge is widely utilized and relatively safe but results in a significant number of readmissions for complications. For patients at higher risk of complications, as indicated by the presence of at least one of five independent predictors, observation for 6 hours or overnight may reduce the need for readmission.

Tetracyclines inhibit connective tissue breakdown by multiple non-antimicrobial mechanisms

A seminal experiment involving a germ-free rat model of connective tissue breakdown (followed soon thereafter by a series of in vitro studies) identified an unexpected non-antimicrobial property of tetracyclines (TCs). This ability of TCs to inhibit matrix metalloproteinases (MMPs) such as collagenase was found to reflect multiple direct and indirect mechanisms of action, and to be therapeutically useful in a variety of dental (e.g., adult periodontitis) and medical (e.g., arthritis, osteoporosis, cancer) diseases. The site on the TC molecule responsible for its MMP-inhibitory activity was identified which led to the development of a series of chemically modified non-antimicrobial analogs, called CMTs, which also have therapeutic potential but do not appear to induce antibiotic side-effects. Longitudinal double-blind studies on humans with adult periodontitis have demonstrated that a sub-antimicrobial dose of doxycycline (previously reported to suppress collagenase activity in the periodontal pocket) is safe and effective and has recently been approved by the FDA as an adjunct to scaling and root planing.

How do tetracyclines work?

This paper is a summary of a panel discussion by the following panelists: L. Golub, J. te Koppele, G. Nieman, M. Nelson, R. Ashley, T. Sorsa, and S. Simon. The panel discussed the mechanisms by which the tetracyclines and their non-antimicrobial counterparts may provide therapeutic efficacy in a variety of chronic and acute diseases.

Tetracyclines inhibit protein glycation in experimental diabetes

Glycation of proteins, which is accelerated in the diabetic state, has been implicated in many of the long-term complications of diabetes. This process can be inhibited by members of the tetracycline family of compounds. This novel finding is supported by studies conducted on drug (streptozotocin)induced Type I and genetic (ZDF/Gmi-fa/fa) Type II diabetic rats. These animals were orally gavaged daily with 5 mg of doxycycline and a variety of non-antimicrobial chemically modified tetracycline derivatives for time periods of 3 weeks to 11 months, while control untreated diabetic and nondiabetic animals were gavaged with vehicle alone (2% CMC). Blood and tissue samples were collected and analyzed for glucose and glycated proteins. None of the treatments had any effect on the severity of hyperglycemia or the intracellular glycation of hemoglobin of either Type I or II diabetic animals. However, the tetracycline analogues did affect the extracellular glycation of several proteins such as those found in the serum as well as skin collagen. In the Type II (ZDF) animals, initial mortality (3-5 months) was seen only in the doxycycline-treated animals, associated with infection by tetracycline-resistant micro-organisms, which was eventually surpassed by mortality rates in the untreated diabetics (6-9 months). CMT treatment not only decreased mortality but also increased longevity in the Type II diabetic animals, most likely by preventing the development of a number of long-term complications of uncontrolled diabetes, including glycation of proteins, that eventually lead to the demise of untreated diabetic animals.

Modulation of the host response in the treatment of periodontitis

Periodontitis has two distinct but interconnected etiologic components: periodontopathic bacteria adjacent to the periodontal tissues, and host-mediated connective tissue-destructive responses to the specific causative bacteria and their metabolic products. Although past and existing therapies have focused primarily on the causative microbial challenge, the host component of periodontal destruction has recently been intensely studied. New treatment strategies that focus on attenuating destructive host responses are emerging. Host modulatory agents, when used adjunctively, may enhance clinical therapeutic responses and make these responses more predictable in the susceptible host. The ongoing development of safe, effective pharmacotherapies that specifically target host response mechanisms, and the introduction of such pharmacotherapies as adjuncts to traditional, antimicrobial interventions may represent a new, integrated approach in the long-term treatment and management of this chronic disease.

Designing courses for the Internet. A conceptual approach

One current higher education paradigm shift is the movement from traditional classroom settings and interactive television satellite transmission to course and program delivery via the World Wide Web (WWW). The authors describe the experiences of faculty in reconceptualizing and redesigning course and program delivery via the Internet. An electronic "template" has been collaboratively developed by multidisciplinary university partners to facilitate this work. The template incorporates an advanced nursing practice conceptual framework based on American Association of Colleges of Nursing (AACN) core educational essentials for advanced practice combined with a continuum of electronic course tools. Strategies, tools, and applications are discussed.

Endoscopic intervention for biliary leaks after laparoscopic cholecystectomy: a multicenter review

BACKGROUND

Endoscopic therapy of biliary tract leaks was uncommon before laparoscopic cholecystectomy. Studies have demonstrated the efficacy of endoscopic drainage by endoscopic sphincterotomy or stent placement. Various endoscopic therapeutic modalities and long-term follow-up of this problem were studied.

METHODS

Members of the Midwest Pancreaticobiliary Group reviewed all patients referred for endoscopic therapy of biliary leaks after laparoscopic cholecystectomy from 1990 to 1994. Long-term follow-up was by direct patient contact.

RESULTS

Fifty patients were referred for endoscopic therapy of biliary leaks. Abdominal pain was present in 94%. The mean time from laparoscopic cholecystectomy to referral was 6.9 days. Therapy consisted of sphincterotomy only in 6 patients, stent only in 13, and sphincterotomy with stent in 31. Biliary leaks were healed in 44 patients at a mean of 5.4 weeks. A second or third endoscopic procedure was necessary to achieve healing in five patients. Two stent-related complications were noted. Percutaneous or surgical drainage of biliary fluid collections was required in 16 patients. The mean hospital stay for treatment of the leak was 11.1 days after endoscopic therapy. On follow-up (mean 17.5 months), all patients were well except two with mild abdominal discomfort.

CONCLUSIONS

Endoscopic sphincterotomy, stent placement, or sphincterotomy with stent are effective in healing biliary leaks after laparoscopic cholecystectomy. Despite prolonged treatment for the leak, patients did well on long-term follow-up.

A matrix metalloproteinase inhibitor reduces bone-type collagen degradation fragments and specific collagenases in gingival crevicular fluid during adult periodontitis

OBJECTIVE AND DESIGN

To determine whether an inhibitor of matrix metalloproteinases (MMPs), administered to human subjects in a dental school research clinic, can reduce bone-type collagen degradation fragments in oral inflammatory exudates containing excessive levels of collagenase.

MATERIALS AND SUBJECTS

Gingival crevicular fluid (GCF) was collected from 18 subjects with adult periodontitis whose clinical findings (gingival inflammation, pocket depth, and bone loss on radiographs) predicted excessive MMP activity in their periodontal pockets.

TREATMENT

One month before the baseline appointment, plaque and calculus were removed from the teeth by supra- and subgingival scaling. After collection of GCF from 8-12 pocket sites per subject and recording of clinical indices, 12 of the 18 subjects were treated with doxycycline at a low dosage (20 mg b.i.d.) known via an extensive literature to suppress mammalian MMP activity by a non-antimicrobial mechanism. The remaining 6 subjects were followed without drug treatment.

METHODS

At the baseline, 1 and 2-month appointments, GCF samples were analyzed for ICTP. (carboxyterminal peptide, a pyridinoline-containing fragment of Type I collagen) and osteocalcin by radioimmunoassay, as well as collagenolytic enzyme activity and MMP species (Western blot). Statistical analyses were determined by ANOVA.

RESULTS

GCF ICTP and functional collagenase activity (but not osteocalcin levels) were significantly reduced (p < 0.05) in the doxycycline-treated subjects at both 1 and 2 month evaluations: there was no such change in the non-treated subjects. Western blots revealed that neutrophil-type collagenase (MMP-8) was the predominant MMP; MMP-13, which has been associated with pathologic collagenolysis including bone resorption, was detected in human GCF for the first time and was more substantially reduced than MMP-8.

CONCLUSION

This is the first demonstration in human subjects of the simultaneous reduction of excessive MMP activity with concomitant reduction in levels of collagen degradation fragments. The findings are potentially applicable to a wide variety of human diseases characterized by excessive collagenase activity.

Pitfalls in diagnosis of Lyme disease. What you need to know about serologic testing

Lyme disease can be difficult to recognize because not all patients have erythema migrans or other classic symptoms. Therefore, laboratory testing has become an important aid to clinical diagnosis. But the story doesn't end there-serologic testing presents another set of problems and concerns. Drs. Still and Ryan explain how aspects of the disease itself and various factors inherent in the available tests can affect laboratory results.

Complications of endoscopic biliary sphincterotomy

BACKGROUND

Endoscopic sphincterotomy is commonly used to remove bile-duct stones and to treat other problems. We prospectively investigated risk factors for complications of this procedure and their outcomes.

METHODS

We studied complications that occurred within 30 days of endoscopic biliary sphincterotomy in consecutive patients treated at 17 institutions in the United States and Canada from 1992 through 1994.

RESULTS

Of 2347 patients, 229 (9.8 percent) had a complication, including pancreatitis in 127 (5.4 percent) and hemorrhage in 48 (2.0 Percent). There were 55 deaths from all causes within 30 days; death was directly or indirectly related to the procedure in 10 cases. Of five significant risk factors for complications identified in a multivariate analysis, two were characteristics of the patients (suspected dysfunction of the sphincter of Oddi as an indication for the procedure and the presence of cirrhosis) and three were related to the endoscopic technique (difficulty in cannulating the bile duct achievement of access to the bile duct by "precut" sphincterotomy, and use of a combined percutaneous-endoscopic procedure). The overall risk of complications was not related to the patient's age, the number of coexisting illnesses, or the diameter of the bile duct. The rate of complications was highest when the indication for the procedure was suspected dysfunction of the sphincter of Oddi (21.7 percent) and lowest when the indication was removal of bile-duct stones within 30 days of laparoscopic cholecystectomy (4.9 percent). As compared with those who performed fewer procedures, endoscopists who performed more than one sphincterotomy per week had lower rates of all complications (8.4 percent vs. 11.1 percent, P=0.03) and severe complications (0.9 percent vs. 2.3 percent, P=0.01).

CONCLUSIONS

The rate of complications after endoscopic biliary sphincterotomy can vary widely in different circumstances and is primarily related to the indication for the procedure and to endoscopic technique, rather than to the age or general medical condition of the patients.

Healthcare workers and bloodborne pathogens: knowledge, concerns, and practices

Occupational exposure of healthcare workers to bloodborne pathogens and the transmission of human immunodeficiency virus and hepatitis B virus warrant study. This study examined issues related to the transmission of bloodborne pathogens in practice. Findings provide information regarding knowledge level, practices of staff in applying universal precautions, and availability of supplies and equipment. The concerns of nurses along with content for educational programs and suggested approaches to education are outlined.

Potential of tetracyclines to modify cartilage breakdown in osteoarthritis

For several decades, it has been recognized that an imbalance between activated matrix metalloproteinases, generated locally by both infiltrating and resident cells, and their endogenous inhibitors may play a role in the pathologic breakdown of the joint extracellular matrix in osteoarthritis. This understanding has stimulated the search for a number of synthetic matrix metalloproteinase inhibitors that could serve as potential therapeutic agents. Tetracycline analogues are currently on the threshold of approval as anti-matrix metalloproteinases for another extracellular matrix-destructive disease, periodontitis, and this application could be extended to osteoarthritis and rheumatoid arthritis therapy. In this regard, specially formulated low-dose regimens of a commercially available tetracycline, doxycycline, have been used in long-term clinical trials and were found to reduce extracellular matrix breakdown, including bone loss, in adult periodontitis. Matrix metalloproteinase inhibition by tetracycline analogues is now recognized as complex, and multiple mechanisms have been proposed. A series of recently discovered nonantimicrobial chemically modified tetracyclines are potent inhibitors of several classes of matrix metalloproteinases, preventing collagen breakdown and bone loss in a variety of animal models, although these analogues have not yet been approved for human use. Various tetracyclines have reduced the severity of osteoarthritis in animal models, indicating therapeutic potential for this class of compounds in the future.

Local and systemic factors in periodontal disease increase matrix-degrading enzyme activities in rat gingiva: effect of micocycline therapy

We previously reported that both local and systemic factors relevant to the pathogenesis of periodontal disease can increase gingival collagenase activity in rats. Since the degradation of extracellular matrix is an essential feature of periodontal disease and this tissue breakdown requires multiple enzyme interactions, the current study was carried out to determine the effects of bacterial endotoxin (LPS) (a local factor) and diabetes (a systemic factor) on a panel of matrix-degrading enzymes (collagenase, gelatinase, elastase, and beta-glucuronidase) in the gingiva of rats. In addition, the effects of therapy with a semisynthetic tetracycline (minocycline) were investigated. Ten male, Sprague-Dawley rats were made diabetic by IV injection of streptozotocin. Four of the ten rats then received minocycline (10 mg/day) by oral gavage on a daily basis for 3 weeks. Nineteen nondiabetic rats served as controls and 9 of them received 10 microliters of E. coli LPS (10 mg/ml) by injection into the labial gingiva every other day during the last week of the study. The other 10 nondiabetic rats were sham injected with saline into the gingiva. At the end of the 3 week experimental period, gingival tissue and skin were dissected from each rat and extracted for enzyme analysis. Our results showed that diabetes markedly increased the four matrix-degrading enzyme activities in both gingiva and skin. In contrast, local LPS injection increased these enzyme activities in the gingiva alone. Systemic therapy with minocycline completely ameliorated these elevated enzyme levels in diabetic rats in both gingiva and skin. Minocycline added in vitro to the enzyme assay systems containing skin extract from diabetic rats also inhibited collagenase and gelatinase activities, but no inhibition was observed for elastase and beta-glucuronidase activities, indicating that the MMPs and other enzymes were inhibited by minocycline, during diabetes, by indirect and indirect mechanisms, respectively.

Oxygen consumption calculated from the Fick equation has limited utility

OBJECTIVE

To determine if oxygen consumption (VO2) calculated using the Fick relationship (calculated VO2) determines total body VO2 accurately and precisely enough to employ this method during clinical assessment of oxygen transport.

DESIGN

Methods comparison, using repeated measures during four physiologic states: normal heart/normal lungs, heart failure/normal lungs, normal heart/acute lung injury, heart failure/acute lung injury.

SETTING

University research laboratory.

SUBJECTS

Thirteen adult Yucatan pigs.

INTERVENTIONS

Oleic acid-induced acute lung injury; heart failure was induced with a continuous infusion of esmolol.

MEASUREMENTS AND MAIN RESULTS

Calculated VO2 was determined by multiplying thermodilution cardiac output by the arterialvenous oxygen content difference in anesthetized, spontaneously breathing animals. Conditions were tightly controlled so that calculated VO2 would be as accurate as possible. "True" VO2 was measured simultaneously with a water-sealed spirometer (spirometry VO2). Calculated VO2 and spirometry VO2 were determined and analyzed during the four physiologic states listed above. Pooled data also were evaluated. Mean spirometry VO2 and calculated VO2 differed significantly during all four physiologic states and when data were pooled (spirometry VO2 273 +/- 70, calculated VO2 178 +/- 58 mL/min; p < .01). Calculated VO2 consistently underestimated spirometry VO2, as demonstrated by the large, positive bias in pooled data (95 +/- 59 mL of oxygen/min) and in the four physiologic states. Linear regression of data from all four states yielded slopes that were indistinguishable from 1, but y intercepts that varied from -152 to +182. For pooled data, the following equation was used: calculated VO2 = 0.5 x (spirometry VO2 + 46); r2 = .35. Precision in pooled data was 22% of the mean spirometry VO2. Data analysis for the four physiologic states demonstrated results similar to those results obtained when data were pooled.

CONCLUSIONS

Even in a tightly controlled, clinical simulation in the laboratory, calculated VO2 from the Fick relationship systematically underestimated VO2 measured with a water-sealed spirometer. If true VO2 changes, the magnitude and direction of change will be reflected by calculated VO2 but with approximately 20% error in the absolute value. Heart failure, acute lung injury, and their combination did not affect the accuracy of calculated VO2. Therefore, calculating VO2 using the Fick relationship is too inaccurate to be used for research purposes. Because assessment of the directional change of VO2 may be clinically useful, calculated VO2 can be employed with discretion during clinical oxygen transport evaluation, bearing in mind the calculation's inherent imprecision.

Pitfalls in HIV testing. Application and limitations of current tests

Enzyme-linked immunosorbent assay (ELISA) and Western blot assay are the most commonly used laboratory tests for HIV infection. Both detect antibodies to HIV. ELISA results are based on detection of antigen-antibody complexes by using antibodies labeled with an enzyme that produces a color change in the presence of a specific substrate. Currently licensed ELISA tests have greater than 98% sensitivity and specificity for HIV. Western blot analysis detects antibodies to specific HIV antigens and is best used as a confirmatory test. In spite of the high sensitivity and specificity of both tests, false-positive and false-negative results do occur. Physicians should be aware of specific causes of inaccurate results. In individual cases, knowledge of the patient's history and the criteria used by the laboratory performing the test is important.

Streptococcal preseptal cellulitis complicated by the toxic Streptococcus syndrome

BACKGROUND

After decades of decline in the incidence of severe infections secondary to group A streptococci, a dramatic increase in the frequency and severity of infections with these organisms has been reported since 1984, including a "toxic Streptococcus syndrome," resembling staphylococcal toxic shock syndrome. To the authors' knowledge, this entity has never been described after ocular infection.

METHODS

In a previously healthy 3-year-old boy, preseptal cellulitis developed secondary to minor trauma to the eyelid, progressing rapidly to hypotension, respiratory distress, and an erythrodermic desquamating rash. Ocular and blood cultures grew group A beta-hemolytic streptococci. Appropriate antibiotic coverage and management of systemic manifestations led to rapid improvement, although necrosis developed in the right upper anterior eyelid, requiring skin grafts.

RESULTS

More than 3 years since the incident, the patient is free of infection and has a good cosmetic result after skin grafting and revisions for scarring and adhesions.

CONCLUSIONS

Streptococcal preseptal cellulitis is not unusual, particularly after trauma. Ophthalmologists must be aware of the re-emergence of more virulent organisms with increased potential for morbidity and mortality.

Measuring patient satisfaction: a case study

Health care providers are under tremendous pressure to meet consumer demands in order to compete in the rapidly changing health care arena. Through evaluating patient satisfaction, health care providers can learn what the consumer wants from the health care system. This article informs the reader of issues surrounding patient satisfaction data collection instruments, especially the problem of lack of standardization. That is, each instrument measures satisfaction according to different standards. This article presents a case study analysis of one patient satisfaction data collection instrument entitled the Picker-Commonwealth Survey on Patient-Centered Care. Suggestions for revision and further work are addressed.

Efficacy and safety of aerosolized ribavirin in young children hospitalized with influenza: a double-blind, multicenter, placebo-controlled trial

We randomly assigned children hospitalized with influenza who had been ill < or = 48 hours and who had a temperature > or = 37.8 degrees C to receive either ribavirin or placebo. All patients had evaluations performed for fever reduction, use of acetaminophen for temperature > or = 38.3 degrees C, duration and severity of influenza symptoms, and feeding behavior. Sixty-two patients (35 in the placebo group, 27 in the ribavirin group) had a diagnosis of influenza confirmed by laboratory study. The groups did not differ significantly in age, initial signs and symptoms, or in distribution of influenza A or B infections. The time to reduction of temperature < or = 38.3 degrees C for the ribavirin group was 8.9 hours compared with 22.6 hours for the placebo group (p = 0.04). The mean duration of acetaminophen use was 7.4 hours in the ribavirin group and 16.3 hours in the placebo group (p = 0.14). There were no significant differences between the groups in outcome of respiratory rate, pulse rate, cough, or level of consciousness. Convalescent influenza antibody geometric mean titer for the placebo group was 9.8 compared with 3.6 for the ribavirin group (p = 0.04). Ribavirin was more effective than placebo in accelerating normalization of temperature but there were no other significant differences.