Application of carbon monoxide diffusing capacity in the mouse lung

In the past decade the mouse has become the primary animal model of a variety of lung diseases. To assess various mechanisms underlying such pathologies, it is essential to make functional measurements that can reflect the developing pathology. In this regard, the diffusing capacity for carbon monoxide is a variable that directly reflects structural changes in the lung. Although measurement of single-breath diffusing capacity of the lung for carbon monoxide (DL(CO)) has also been previously reported in mice by a number of investigators, a number of technical issues have precluded routine and widespread use of this metric in mouse models. In the present report, we describe a means to quickly and simply measure a dimensionless variable closely related to the DL(CO) in mice, termed a diffusion factor for carbon monoxide (DF(CO)). The DF(CO) procedure involves a 9-s lung inflation with tracer gases in an anesthetized mouse, followed by a 1-min gas analysis time. We have tested the approach with two common models of lung pathology, elastase-induced emphysema and bleomycin-induced fibrosis. Results show a significant 15% reduction in DF(CO) in emphysema, and a 41% reduction in the fibrosis model. Repeat measurements within a mouse were found to be highly reproducible. This pulmonary function test can thus be used to detect structural changes with these pathological models. The method can also be used to measure changes in pulmonary blood volume, since the uptake of CO is highly dependent on this variable in addition to the gas exchange surface area.

Impact of land drainage on peatland hydrology

There is a long history of drainage of blanket peat but few studies of the long-term hydrological impact of drainage. This paper aims to test differences in runoff production processes between intact and drained blanket peat catchments and determine whether there have been any long-term changes in stream flow since drainage occurred. Hillslope runoff processes and stream discharge were measured in four blanket peat catchments. Two catchments were drained with open-cut ditches in the 1950s. Ditching originally resulted in shorter lag times and flashier storm hydrographs but no change in the annual catchment runoff efficiency. In the period between 2002 and 2004, the hydrographs in the drained catchments, while still flashy, were less sensitive to rainfall than in the 1950s and the runoff efficiency had significantly increased. Drains resulted in a distinctive spatial pattern of runoff production across the slopes. Overland flow was significantly lower in the drained catchments where throughflow was more dominant. In the intact peatlands, matrix throughflow produced by peat layers below 10 cm was rare and produced <1% of the runoff. However, in drained peatlands, matrix throughflow in deeper peat layers was common and provided around 23% of the runoff from gauged plots. Macropore flow, the density of soil piping, and pipeflow were significantly greater in drained peatlands than in intact basins. Gradual changes to peat structure could explain the long-term changes in river flow, which are in addition to those occurring in the immediate aftermath of peatland drainage.

Gas chromatographic, mass spectrometric and stable carbon isotopic investigations of organic residues of plant oils and animal fats employed as illuminants in archaeological lamps from Egypt

Man's use of illuminants in lamps or as torches to extend the working day and range of environments accessible to him would have been a major technological advance in human civilisation. The most obvious evidence for this in the archaeological record comes from pottery and stone vessels showing sooting due to the use of a wick in conjunction with a lipid-based fuel or illuminant. A wide range of potential fuels would have been exploited depending upon availability and burning requirements. Reported herein are the results of chemical investigations of a number of lamps recovered from excavations of the site of Qasr Ibrim, Egypt. Gas chromatographic, mass spectrometric and stable carbon isotopic analyses of both free (solvent extractable) and 'bound'(released from solvent extracted pottery by base treatment) lipids have revealed a wide range of saturated fatty acids, hydroxy fatty acids and alpha, omega-dicarboxylic acids. Examination of the distributions of compounds and comparisons with the fatty acid compositions of modern plant oils have allowed a range of fats and oils to be recognised. Specific illuminants identified include Brassicaceae (Cruciferae) seed oil (most likely radish oil, Raphanus sativus), castor oil (from Ricinus communis), animal fat, with less diagnostic distributions and delta(13)C values being consistent with low stearic acid plant oils, such as linseed (Linum usitatissimum) or sesame (Sesamum indicum) oils. The identifications of the various oils and fats are supported by parallel investigations of illuminant residues produced by burning various oils in replica pottery lamps. The findings are entirely consistent with the classical writers including Strabo, Pliny and Theophrastrus.

ADAM gene expression and regulation during human osteoclast formation

In this study, we identified the expression and the regulation of ADAM members (a disintegrin and metalloprotease) at both gene and protein levels during human osteoclast differentiation and activity. Human peripheral blood monocytes (HPBMC) treated with M-CSF and RANKL were used as an in vitro fusion model. In parallel, we used human osteoclastoma (OCL) tumor as a source of mature osteoclasts, and human osteoblastic cells as a control representing nonfusing and non-resorbing bone cells. RT-PCR using ADAM-specific primers enabled us to identify the expression of ADAM 8, 9, 10, 15, 17, and 28 in both osteoclasts and osteoblasts. Using primers specific for each ADAM 12 isoform (L and S), we observed a strong signal for both forms (ADAM 12L and ADAM 12S) in osteoblastic cells, while only ADAM 12S was detectable in HPBMC-derived osteoclasts and osteoclastoma. Gene regulation was studied using real-time PCR analysis performed during HPBMC differentiation; this showed a progressive increase of ADAM 12 mRNA level from day 1 to 8 of the culture, while at around day 9, ADAM 12 mRNA level decreased 2-fold. We also showed that ADAM 8, ADAM 17, and ADAM 28 decreased according to the stage of HPBMC differentiation or fusion. ADAM 10 was unaltered during cell fusion. However, confocal immunolocalization showed that ADAM 10 protein re-localized from the nuclei and cytoplasm to the plasma membrane during culture and to the ruffled border in resorbing cells. The same re-localization process was observed using an ADAM 12S-specific antibody during HPBMC differentiation. Between days 12 and 14, ADAM 12 co-localized with the F-actin ring, and at day 15, a strong signal was also present in ruffled border or sealing zone area of osteoclasts. Our results describe the expression and regulation of various ADAMs in human bone cells and the selective expression of ADAM 12L in osteoblasts. Our gene regulation and protein localization studies suggest a function for ADAM 10 and ADAM 12S in the formation of osteoclasts from HPBMC and resorption activity.

Targeting of biotinylated compounds to its target tissue using a low-density lipoprotein receptor–avidin fusion protein

The very high binding affinity of avidin to biotin is one of the highest to occur in nature. We constructed a fusion protein composed of avidin and the endocytotic LDL receptor in order to target biotinylated molecules to cells of the desired tissues. In addition to the native avidin, charge-mutated and nonglycosylated avidins were utilized as part of the fusion proteins, in order to modify its properties. All of the fusion protein versions retained the biotin-binding capacity. Although the specificity was not increased, however, fusion proteins composed of natural avidin and nonglycosylated avidin bound most efficiently to the biotinylated ligands. Fluorescence microscopy and atomic force microscopy studies revealed the expression of the fusion protein on cell membranes, and demonstrated specific and high-affinity binding of biotin to the low-density lipoprotein receptor (LDLR)-avidin fusion protein in vitro. Additionally, systemically administered biotinylated ligand targeted with high specificity the intracerebral tumors of rats that were expressing fusion protein after the virus-mediated gene transfer. These results suggest that local gene transfer of the fusion protein to target tissues may offer a novel tool for the delivery of biotinylated molecules in vitro and in vivo for therapeutic and imaging purposes.

The development and use of a triage protocol for patients with dental problems contacting an out-of-hours general medical practitioner cooperative

PURPOSE OF THE STUDY

The number of patients contacting general medical practitioner (GMP) out-of-hours services with dental problems is perceived to be a significant problem by the medical profession. This study was undertaken to design and pilot a triage protocol that could be used by non-dental staff to refer callers with dental complaints for appropriate treatment.

BASIC PROCEDURES

A triage protocol was designed to address the patient conditions considered to be relevant to emergency dental care. The triage protocol was piloted for three months at a GMP cooperative in North Wales, which provided an out-of-hours service for 61 GMPs. Baseline data were collected for three months prior to the introduction of the triage protocol.

MAIN FINDINGS

The study showed that the number of dental callers contacting the out-of-hours service was not as great as GMPs imagined, and was similar to other studies. The introduction of the triage protocol resulted in a rise in the number of callers asked to call the general dental practitioner (GDP) support line. The number of unregistered patients given the name of a dentist also increased. The need to make a second telephone call seemed not to affect patient satisfaction since when patients were later questioned on their experience, those who had used the service since the introduction of the triage protocol were more likely to be satisfied with the service.

PRINCIPAL CONCLUSIONS

This study provides some evidence that a triage protocol can be used successfully by non-dental staff to sift requests for out-of-hours emergency dental care.

Cell adhesion molecules in human osteoblasts: structure and function

Osteoblasts and bone lining cells form a near continuous layer covering the bone surface and interactions between these cells and the organic matrix of bone are important determinants of osteoblast proliferation and differentiation. In addition, cells of the osteoblast-lineage form functional communications with each other, with the extra-cellular matrix and with osteocytes through cytoplasmic processes extending through canaliculi in the bone. Together, these cells form a network of putative importance in the regulation of skeletal homeostasis. Cell-cell and cell-matrix interactions are mediated by members of several families of cell adhesion molecules, and knowledge of their interactions will be of fundamental importance in understanding the role of osteoblast in skeletal turnover. Here, the expression pattern of members of the major families of cell adhesion molecules by cells of the osteoblast lineage is reviewed. Special emphasis has been placed on human tissues. In addition, the possibility that cells at progressive stages of the osteoblast lineage have different profiles of cell adhesion molecule expression is explored, and the putative significance of cell-matrix interactions in human skeletal disease briefly discussed.

Effect of selective or combined inhibition of integrins alpha(IIb)beta(3) and alpha(v)beta(3) on thrombosis and neointima after oversized porcine coronary angioplasty

BACKGROUND

Thrombosis and neointima formation limit the efficacy of coronary angioplasty (PTCA). Clinical trials have implicated the adhesion molecules integrin alpha(IIb)beta(3) and integrin alpha(v)beta(3) in these processes. The roles of these molecules in vascular smooth muscle cell adhesion, platelet aggregation, and the thrombotic and neointimal response to oversize porcine PTCA was investigated by use of a selective alpha(IIb)beta(3) antagonist (lamifiban), a selective alpha(v)beta(3) antagonist (VO514), and a combined alpha(IIb)beta(3)/alpha(v)beta(3) antagonist (G3580).

METHODS AND RESULTS

In vitro, both alpha(v)beta(3) inhibitors caused dose-dependent inhibition of porcine vascular smooth muscle cell adhesion to vitronectin but not to collagen type IV, fibronectin, or laminin, whereas selective alpha(IIb)beta(3) inhibition had no effect. Intravenous infusions of either alpha(IIb)beta(3) inhibitor in swine profoundly inhibited ex vivo platelet aggregation to ADP, whereas selective alpha(v)beta(3) inhibition had no effect. In a porcine PTCA model, intravenous infusions of the integrin antagonists were administered for 14 days after oversized balloon angioplasty injury. After PTCA, there was regional upregulation of integrin alpha(v)beta(3) in the developing neointima, as assessed by immunohistochemistry. Six hours after PTCA, obstruction of lumen by thrombus was reduced significantly by alpha(IIb)beta(3) inhibition compared with either control or alpha(v)beta(3) inhibition (mean control, 18.7%; VO514, 18.5%; lamifiban, 6.4%; G3580, 7.9%). Twenty-eight days after PTCA, there was a significant reduction of neointima with inhibitors of either integrin (mean intima/media ratio: control, 3.08; VO514, 1.33; lamifiban, 0.97; G3580, 1.32).

CONCLUSIONS

We conclude that both integrin alpha(IIb)beta(3) and integrin alpha(v)beta(3) participate in neointima development after experimental angioplasty.

Opinions and experiences in general practice on osteoporosis prevention, diagnosis and management

We determined to survey the general practice population regarding their attitudes to and knowledge of osteoporosis as a baseline prior to publication of national guidelines for the management of osteoporosis. All 2515 general practitioners registered in the 10 Health Authorities of the North Thames region, London, UK were surveyed by a postal questionnaire. Responses relating to epidemiology, public health and education on osteoporosis were analyzed. The overall response was 1153 (46%). General practitioners who responded were younger, predominantly female and in group practice. There is considerable awareness of the importance of preventing osteoporosis. General practitioners are active in identifying groups at risk, particularly those who are aged 40 years and older. A prevention strategy for osteoporosis is viewed as effective. However, two thirds of general practitioners remain unconvinced about the efficacy of drug therapy. Education on osteoporosis is considered inadequate. General practitioners would welcome further information on management issues and access to osteoporosis services. In conclusion, educational initiatives will be important both at undergraduate and postgraduate levels to increase awareness and knowledge of osteoporosis. General practitioners are aware of the public health impact of this condition and express a preference for educational material of direct relevance to the care of their patients. Therefore better cooperation between primary and secondary care should lead to ways of breaking down barriers to change in clinical practice and promoting fully integrated care of patients with osteoporosis.

Survival advantage of stentless aortic bioprostheses

BACKGROUND

Bioprostheses (BPs) are used to avoid anticoagulation after aortic valve replacement (AVR) in patients over 65 years of age. Stentless BPs offer established hemodynamic benefits. We sought to determine whether these advantages translate into improved survival.

METHODS

Between 1993 and 1997, follow-up data (for Food and Drug Administration submission) were collected prospectively for 160 consecutive, unselected hospital survivors who received the Freestyle valve (FS). Equivalent data were collected for 247 Carpentier-Edwards (CE) porcine xenograft patients. Detailed comparative statistical analysis was used to compare events and survival between the groups. Follow-up was 100% complete for the FS (5.2 years maximum; mean 3.2+/-1.0 years) group and 98% (7.2 years maximum; mean 3.8+/-2.0 years) for CE.

RESULTS

The groups were well matched in age (FS, 73+/-6 years; CE, 74+/-6 years), gender (FS, 58% male; CE, 62% male), ventricular function, and number of patients requiring coronary grafts (FS, 41%; CE, 37%). Actuarial survival at 5 years was 84% for FS versus 69% for CE (p = 0.023 Kaplan Meier, p = 0.009 Cox). Annual mortality rates were 3.6% for FS versus 7.1% for CE (p = 0.001). Thromboembolic rate was 0.8% per year for FS and 2.4% for CE (p = 0.024) without a difference in cardiac rhythm. Incidence of nonstructural dysfunction (paravalvular leak) was 0.2% for FS versus 1.3% for CE (p = 0.020).

CONCLUSIONS

By 5 years, the stentless valve patients had improved survival and reduced adverse events. Though differences in durability are yet to be proved, our findings support the use of stentless bioprostheses in this age group.

Mechanical bridge to recovery in fulminant myocarditis

A patient with acute fulminant lymphocytic myocarditis and cardiogenic shock was successfully treated by mechanical off loading of the left ventricle. A nonpulsatile left-heart bypass was undertaken with an implantable centrifugal blood pump. Careful weaning resulted in device removal on the seventh day. Left and right ventricular function is sustained at 7 months. Widespread application of this method depends on the availability of an inexpensive user friendly blood pump, appropriate weaning protocols and emerging strategies to promote sustainable myocardial recovery.

Smooth muscle cell matrix metalloproteinase production is stimulated via alpha(v)beta(3) integrin

This study tests the hypothesis that alpha(v)beta(3) integrin receptors play a critical role in smooth muscle cell (SMC) migration after arterial injury and facilitate migration through the upregulation of matrix metalloproteinase (MMP) activity. We showed that beta(3) integrin mRNA was upregulated by SMCs in the balloon-injured rat carotid artery in coincidence with MMP-1 expression and early SMC migration. Treatment with the beta(3) integrin-blocking antibody F11 significantly decreased SMC migration into the intima at 4 days after injury, from 110.8+/-30.8 cells/mm(2) in control rats to 10.29+/-7.03 cells/mm(2) in F11-treated rats (P=0.008). By contrast, there was no effect on medial SMC proliferation or on medial SMC number in the carotid artery at 4 days. In vitro, we found that human newborn SMCs produced MMP-1 but that adult SMCs did not. This was possibly due to the fact that newborn SMCs expressed alpha(v)beta(3) integrin receptors, whereas adult SMCs did not. Stimulation of newborn (alpha(v)beta(3)+) SMCs with osteopontin, a matrix ligand for alpha(v)beta(3), increased MMP-1 production from 114.4+/-35.8 ng/mL at 0 nmol/L osteopontin to 232.5+/-57.5 ng/mL at 100 nmol/L osteopontin. Finally, we showed that stimulation of newborn SMCs with platelet-derived growth factor-BB and osteopontin together increased the SMC production of MMP-9. Thus, our results support the hypothesis that SMC alpha(v)beta(3) integrin receptors play an important role in regulating migration by stimulating SMC MMP production.

Community control of Chlamydia trachomatis

In order to determine the amount of Chlamydia trachomatis that is diagnosed outside genitourinary medicine (GUM) clinics in a large university city, a review of all positive chlamydial infections diagnosed on specimens received from hospitals (non-GUM) and community sources in 1996 was performed. It was also ascertained whether these patients subsequently attended at GUM. Eight hundred and nine cases of C. trachomatis were diagnosed during the study period. Three hundred and ninety-seven (49%) were initially diagnosed outside GUM of which 264 (66.5%) were referred, giving an overall involvement of GUM in 667 (83.6%) of all cases. The proportion of cases referred varied according to service: Family Planning Clinics 94.5%, Obstetrics and Gynaecology 73%, General Practice 52.5%. Referral rates also showed within service variation, with University Health Services referring 19% vs 73% (P < 0.001). High levels of referral to GUM of patients diagnosed with C. trachomatis are achievable, but referrals show inter- and intra-service variations. Efforts should be made to improve referral rates from those services with the lowest rates.

IN CONCLUSION

(1) The proportion of cases of C. trachomatis diagnosed in the community who are referred to a GUM clinic, varies according to service type. (2) Referral rates vary within services and (3) Distance of services from a GUM clinic does not appear to influence referral rates.

The pharmacokinetics of ziprasidone in subjects with normal and impaired renal function

AIMS

To assess whether renal impairment influences the pharmacokinetics of ziprasidone, and to determine whether ziprasidone is cleared via haemodialysis.

METHODS

Thirty-nine subjects with varying degrees of renal impairment were enrolled into an open-label, multicentre, multiple-dose study and assigned to four groups according to their renal function: normal (group 1, creatinine clearance > 70 ml min(-1); mildly impaired (group 2, creatinine clearance 30-60 ml min(-1); moderately impaired (group 3, creatinine clearance 10-29 ml min(-1), and severely impaired (group 4, requiring haemodialysis three times-a-week). Subjects received ziprasidone 40 mg day(-1), given orally with food, as two divided daily doses for 7 days and a single 20 mg dose on the morning of day 8. Pharmacokinetic variables were determined from multiple venous blood samples collected on days 1 and 8 (haemodialysis day for subjects with severe renal impairment). Additional samples were collected from subjects with severe renal impairment on day 7 (nonhaemodialysis day).

RESULTS

On day 1 there were no statistically significant differences in the pharmacokinetics (AUC(0, 12 h), Cmax, tmax) of ziprasidone among subjects with normal renal function and those with mild, moderate and severe renal impairment. The AUC(0,12 h) and Cmax in subjects with mildly impaired renal function were statistically significantly greater than in those with moderately impaired renal function (P = 0.0163-0.0385). The mean AUC(0,12 h) was 272, 370, 250 and 297 ng ml(-1) h in groups 1, 2, 3 and 4, respectively. Corresponding mean Cmax values were 47, 61, 41 and 50 ng ml(-1) and corresponding mean tmax values were 5, 6, 5 and 5 h. On day 8 there were no statistically significant differences in the pharmacokinetics (AUC(0,12 h), Cmax, tmax, lambda(z), Fb) of ziprasidone among subjects with normal renal function and those with moderate or severe renal impairment. The AUC(0,12 h) in subjects with mild renal impairment was statistically significantly greater than those in the other three groups (P = 0.0025-0.0221), but this was not considered clinically significant. The mean AUC(0,12 h) were 446, 650, 389 and 427 ng ml(-1) h in groups 1, 2, 3 and 4, respectively. Corresponding mean Cmax values were 68, 93, 54 and 70 ng ml(-1), corresponding mean tmax values were 4, 5, 4 and 5 h and corresponding mean lambda(z) were 0.14, 0.11, 0.14 and 0.17 h(-1). The mean percentage Fb was 99.84-99.88% across all groups and the mean t(1/2),z ranged from 4.2 to 6.4 h. Comparison of the mean AUC(0,12 h) and Cmax values in subjects with severe renal impairment on day 7 with those on day 8 suggested that haemodialysis does not have a clinically significant effect on the pharmacokinetics of ziprasidone.

CONCLUSIONS

The findings of this study indicate that mild-to-moderate impairment of renal function does not result in clinically significant alteration of ziprasidone pharmacokinetics and therefore does not necessitate dose adjustment.

Pharmacokinetics of oral and intravenous dolasetron mesylate in patients with renal impairment

In an open-label, randomized, two-way complete crossover study, the influence of renal impairment on the pharmacokinetics of dolasetron and its primary active metabolite, hydrodolasetron, were evaluated. Patients with renal impairment were stratified into three groups of 12 based on their 24-hour creatinine clearance (Cl(cr)): group 1, mild impairment (Cl(cr) between 41 and 80 mL/min); group 2, moderate impairment (Cl(cr) between 11 and 40 mL/min); and group 3, endstage renal impairment (Cl(cr) < or = 10 mL/min). Twenty-four healthy volunteers from a previous study served as the control group. Each participant received a single intravenous or oral 200-mg dose of dolasetron mesylate on separate occasions. Serial blood samples were collected up to 60 hours after dose for determination of dolasetron and hydrodolasetron, and urine samples were collected in intervals up to 72 hours for determination of dolasetron, hydrodolasetron, and the 5' and 6'-hydroxy metabolites of hydrodolasetron. Because plasma concentrations were low and sporadic, pharmacokinetic parameters of dolasetron were not calculated after oral administration. Although some significant differences in area under the concentration-time curve (AUC0-infinity), volume of distribution (Vd), systemic clearance (Cl), and elimination half-life (t1/2) of the parent drug were observed between control subjects and patients with renal impairment, there were no systematic findings related to degree of renal dysfunction. The elimination pathways of hydrodolasetron include both hepatic metabolism and renal excretion. Consistent increases in mean Cmax, AUC0-infinity, and t1/2 and decreases in renal and total apparent clearance of hydrodolasetron were seen with diminishing renal function after intravenous administration of dolasetron mesylate. No consistent changes were found after oral administration. Urinary excretion of hydrodolasetron and its metabolites decreased with decreasing renal function, but the profile of metabolites remained constant. Dolasetron was well tolerated in all three groups of patients. Based on these findings, no dosage adjustment for dolasetron is recommended in patients with renal impairment.