Influence of bone marrow on membrane-guided bone regeneration of segmental long-bone defects in rabbits

Defects 10 mm long were created in long bone in the diaphysis of both radii of 18 rabbits (test and control side). On the test side, ingrowth of bone marrow into the defects was hindered or delayed by: plugging the opening of the cut bone ends with gutta-percha points (n = 7); plugging with Gelfoam (n = 6); or by removing the bone marrow by flushing with saline (n = 5). The defects on both test and control side were covered with an expanded polytetrafluoroethylene membrane, shaped as a tube. Healing was followed with radiographs for four to five months, after which the animals were killed and ground sections of the areas of the defects were prepared for histological examination. On the control side, nine of 18 animals had complete osseous bridging of the defect, and a small transverse non-mineralised zone remained in the centre of the healed defect in the other animals. This zone consisted of loose connective and cartilagenous tissue as well as connective tissue obviously derived from the outside of the membrane. By preventing or delaying the ingrowth of bone marrow we retarded the regeneration of mineralised bone, particularly in the gutta-percha and flushed bone marrow groups. The principle of guided tissue regeneration may be used to achieve regeneration of extensive long-bone defects. Any attempts to delay or prevent bone marrow ingrowth into the defects did retard regeneration of segmental long-bone defects.     

Changes in body weight and physical performance after receiving dietary advice in patients with chronic obstructive pulmonary disease (COPD): 1-year follow-up

Nutritional studies in patients with chronic obstructive pulmonary disease (COPD) are often based on oral nutritional supplementation and are of short duration. Our aim was to study the changes in body weight and physical performance in COPD patients after receiving the dietary advice for 1 year. Thirty-six patients with COPD as a primary diagnosis (mean age: 68.5 ± 7.8 years), referred to a pulmonary rehabilitation program were studied. Each patient received dietary advice individually. Body weight had increased significantly by 1.3 kg (p = 0.02) and walking distance by 83.2 m (p = 0.007) after 1 year. There was an increase in mean handgrip strength after 1 year (1.6 kg, p = 0.07). The mean intake of energy and protein expressed as percent of energy and protein requirement had increased after 1 year (15%, p < 0.001, and 5.6%, p = 0.09, respectively). Handgrip strength correlated significantly with energy (r = 0.53, p = 0.002), fat (r = 0.50, p = 0.02) and protein intake (r = 0.41, p = 0.002) after 1 year. In conclusion, positive effects on body weight, handgrip strength and walking distance in patients with COPD were seen after receiving dietary advice with a 1-year follow-up.     

Dexamethasone inhibits respiratory glycoconjugate secretion from feline airways in vitro by the induction of lipocortin (lipomodulin) synthesis

The effect of glucocorticoids on respiratory glycoconjugate (RGC) secretion was studied in a cat tracheal organ culture system. Dexamethasone (10(-5) to 10(-9) M) added to culture medium for 24 h caused a dose-related reversible inhibition of RCG of as much as 40% with a peak effect at 24 to 60 h after initiation of dexamethasone treatment. A monoclonal antilipocortin antibody added to the cultures blocked the inhibitory effect of dexamethasone on RGC secretion and accelerated the reversal of the dexamethasone effect after discontinuation of dexamethasone treatment. A control antibody without antilipocortin activity had no effect on RGC secretion or dexamethasone-induced inhibition of RGC secretion. Measurement of the concentration of lipocortin in airways revealed a 220% increase after treatment with dexamethasone for 24 h. We conclude that dexamethasone inhibits RGC secretion through the induction of lipocortin synthesis.     

Isolation and expression of the Pneumocystis carinii dihydrofolate reductase gene.

Pneumocystis carinii dihydrofolate reductase (DHFR; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) cDNA sequences have been isolated by their ability to confer trimethoprim resistance to Escherichia coli. Consistent with the recent conclusion that P. carinii is a member of the Fungi, sequence analysis and chromosomal localization show that DHFR is neither physically nor genetically linked to thymidylate synthase. Expression of recombinant P. carinii DHFR in heterologous hosts provides an abundant source of the enzyme that may form a basis for the development of new therapies for this enigmatic pathogen. Studies with the recombinant enzyme show that trimethoprim is a very poor inhibitor of P. carinii DHFR and, in fact, is a more potent inhibitor of human DHFR.     

Independent risk of mechanical ventilation for AIDS-related Pneumocystis carinii pneumonia associated with bronchoalveolar lavage neutrophilia.

The use of mechanical ventilation (MV) for AIDS-related Pneumocystis carinii pneumonia (PCP) has varied over time. The introduction of adjunctive corticosteroid therapy has changed the pathophysiology of PCP. In the present study, we attempted to identify factors predictive of severe respiratory failure requiring MV amongst patients with PCP treated in the era of adjunctive corticosteroid therapy. Furthermore, we studied factors associated with survival in relation to MV. Of 170 consecutive patients with AIDS-related PCP, 18 (11%) required MV. Thirteen of 18 ventilated patients died (72%). In a logistic regression analysis, higher age, increased bronchoalveolar lavage (BAL) neutrophilia and a positive BAL cytomegalovirus CMV culture were associated with the need of MV. In multivariate analyses, only BAL neutrophilia remained independently predictive of mechanical ventilation. In conclusion, short-term mortality remained high after the introduction of adjunctive corticosteroid therapy. BAL neutrophilia may be a useful prognostic marker to identify patients at high risk of requiring mechanical ventilation.     

Changes in the cause of death among HIV positive subjects across Europe: results from the EuroSIDA study

OBJECTIVES: The causes of death among HIV-positive patients may have changed since the introduction of highly active antiretroviral therapy (HAART). We investigated these changes, patients who died without an AIDS diagnosis and factors relating to pre-AIDS deaths. METHODS: Analyses of 1826 deaths among EuroSIDA patients, an observational study of 8556 patients. Incidence rates of pre-AIDS deaths were compared to overall rates. Factors relating to pre-AIDS deaths were identified using Cox regression. RESULTS: Death rates declined from 15.6 to 2.7 per 100 person-years of follow-up (PYFU) between 1994 and 2001. Pre-AIDS incidence declined from 2.4 to 1.1 per 100 PYFU. The ratio of overall to pre-AIDS deaths peaked in 1996 at 8.4 and dropped to < 3 after 1998. The adjusted odds of dying following one AIDS defining event (ADE) increased yearly (odds ratio, 1.53; P < 0.001), conversely the odds of dying following three or more ADE decreased yearly (odds ratio, 0.79; P < 0.001). The proportion of deaths that followed an HIV-related disease decreased by 23% annually; in contrast there was a 32% yearly increase in the proportion of deaths due to known causes other than HIV-related or suicides. Injecting drug users (IDU) were significantly more likely to die before an ADE than homosexuals (relative hazard, 2.97; P < 0.0001) and patients from northern/eastern Europe (relative hazard, 2.01; P < 0.0001) were more likely to die pre-AIDS than southern patients. CONCLUSIONS: The proportion of pre-AIDS deaths increased from 1994 to 2001; however, the incidence of pre-AIDS deaths and deaths overall declined. IDU and subjects from northern/eastern Europe had an increased risk of pre-AIDS death. HIV-positive patients live longer therefore it is essential to continue to monitor all causes of mortality to identify changes.     

Albuminuria as a predictor of heart failure hospitalizations in patients with type 2 diabetes

BACKGROUND: Heart failure (HF) occurs more frequently and is a significant cause of mortality in diabetic patients. The purpose of the current study is to ascertain risk factors that are predictive of HF hospitalizations in type 2 diabetic patients. METHODS: Longitudinal observational study of type 2 diabetic patients with baseline diastolic blood pressures > or =80 mm Hg and no history of New York Heart Association class III-IV HF or a serum creatinine > or =2.5 mg/dL nested within a randomized clinical trial. The outcome measure of this study was the first occurrence of HF hospitalization over a 5-year follow-up period. RESULTS: Patients with overt albuminuria at baseline had a higher and earlier occurrence of HF hospitalizations than those with micro- or normoalbuminuria (13.6% versus 3.3%, odds ratio [OR]=3.1, 95% confidence interval [CI]=2.15-4.60, P<.0001). In the multiple logistic regression analyses, the presence of overt albuminuria (OR 5.4, 95% CI=2.3-12.5, P<.001), history of myocardial infarction (OR 4.6, 95% CI=1.6-13.1, P=.004) and a history of New York Heart Association Class I or II HF (OR 8.0, 95% CI=2.2-28.6, P=.0014) at baseline were independently associated with HF hospitalizations. CONCLUSIONS: Overt albuminuria predicts the occurrence of HF hospitalizations in type 2 diabetic patients. Thus early aggressive treatment of diabetic nephropathy should be investigated as a means of preventing of HF.     

Escherichia coli clonal group A causing bacteraemia of urinary tract origin

Escherichia coli clonal group A (CgA) causes disease in humans. This is the first study investigating the prevalence of CgA among E. coli from non-urine, extraintestinal infections in a northern European country. E. coli blood (n = 196) and paired urine (n = 195) isolates from the same patients with bacteraemia of urinary tract origin were analysed. The isolates were collected from January 2003 through May 2005 at four hospitals in Copenhagen, Denmark. Pulsed-field gel electrophoresis (PFGE) patterns, antimicrobial resistance and patient characteristics were determined for all CgA isolates; presence of virulence-associated genes (VAGs) and serotypes were determined for the blood CgA isolates. Thirty blood isolates (15%) belonged to CgA. CgA blood isolates were associated with female patients and sulfamethoxazole-trimethoprim resistance and they harboured a distinctive VAG profile. The blood and urine isolates from each pair were found to be related in 26 of 27 CgA blood/urine pairs, confirming a urinary tract origin of infection. Furthermore, a relationship between the PFGE patterns of CgA blood/urine isolates and CgA isolates from UTI patients in general practice and a CgA isolate from a community-dwelling human reported previously, was found, suggesting a community origin of CgA. The finding of CgA strains in 15% of the E. coli bloodstream infections with a urinary tract origin in Denmark suggests that CgA constitutes an important clonal lineage among extraintestinal pathogenic E. coli. A reservoir of this pathogenic E. coli group in the community causing not only UTI but also more severe infections such as bacteraemia has implications for public health.     

Antagonistic effects of 24R,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 on L-type Ca2+ channels and Na+/Ca2+ exchange in enterocytes from Atlantic cod (Gadus morhua)

There is mounting evidence that vitamin D and its metabolites play important roles in regulating plasma calcium concentrations in teleost fish as in other vertebrates. The aims of the present study were to elucidate the possible cellular target mechanisms for the rapid actions of 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in Atlantic cod enterocytes at physiological doses, and to establish the concentration and thus the physiological range of circulating 24R,25(OH)(2)D(3), 25(OH)D(3) and 1,25(OH)(2)D(3) in the Atlantic cod. The plasma concentrations of 25(OH)D(3), 1,25(OH)(2)D(3) and 24R,25(OH)(2)D(3) were 15.3 +/- 2.7nM, 125.1 +/- 12.3pM and 10.1 +/- 23.5nM respectively. Exposure of enterocytes to 10mM calcium (Ca(2+)) evoked an increase in intracellular Ca(2+) concentrations ([Ca(2+)](i)). This increase was suppressed by 24R,25(OH)(2)D(3) dose-dependently, with an EC(50) of 4.9nM and a maximal inhibition of 60%. 24R,25(OH)(2)D(3) (20nM) abolished an increase in [Ca(2+)](i) (approximately 252%) in the control enterocytes exposed to 10microM S(-)-BAYK-8644, suggesting that the hormone acts by inhibiting Ca(2+) entry through L-type voltage-gated Ca(2+) channels. Administration of 20nM 24R,25(OH)(2)D(3) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 20%, indicating a release of Ca(2+) from intracellular stores. Administration of 25(OH)D(3) (20nM) resulted in a biphasic change in the enterocyte [Ca(2+)](i): within 1--5s, it decreased to 87 +/- 12nM below its mean basal [Ca(2+)](i) (334 +/- 13nM), followed by a rapid recovery of [Ca(2+)](i) to a new level, 10% lower than the initial [Ca(2+)](i). The rapid decrease, the recovery rate and the final [Ca(2+)](i) were all affected dose-dependently by 25(OH)D(3), with EC(50) values of 8.5, 17.0 and 18.9nM respectively. Furthermore, the effects of 25(OH)D(3) were sensitive to sodium (Na(+)), bepridil (10microM) and nifedipine (5 microM), suggesting that 25(OH)D(3) regulates the activity of both basolateral membrane-associated Na(+)/Ca(2+) exchangers and brush border membrane-associated L-type Ca(2+) channels. Administration of 25(OH)D(3) (10nM) to enterocytes in the absence of extracellular Ca(2+) increased [Ca(2+)](i) by approximately 18%, indicating a release of Ca(2+) from intracellular stores. 1,25(OH)(2)D(3) also affected enterocyte [Ca(2+)](i) in a biphasic manner: the rapid decrease, the recovery rate, and the mean final [Ca(2+)](i) were all affected dose-dependently, with EC(50) values of 8.3, 24.5 and 7.7nM respectively. The high EC(50) values for 1,25(OH)(2)D(3) compared with circulating concentrations of 1,25(OH)(2)D(3) (130pM) suggest that this effect is pharmacological, rather than of physiological relevance in enterocyte Ca(2+) homeostasis of the Atlantic cod. It is concluded that 24R,25(OH)(2)D(3) has a physiological role in decreasing intestinal Ca(2+) uptake via inactivation of L-type Ca(2+) channels, whereas the physiological role of 25(OH)D(3) is to increase enterocyte Ca(2+) transport via activation of Na(+)/Ca(2+) exchangers, concurrent with activation of L-type Ca(2+) channels.