Experimental and Theoretical Study of the Electronic Structures of Lanthanide Indium Perovskites LnInO3

Ternary lanthanide indium oxides LnInO₃ (Ln = La, Pr, Nd, Sm) were synthesized by high-temperature solid-state reaction and characterized by X-ray powder diffraction. Rietveld refinement of the powder patterns showed the LnInO₃ materials to be orthorhombic perovskites belonging to the space group Pnma, based on almost-regular InO₆ octahedra and highly distorted LnO₁₂ polyhedra. Experimental structural data were compared with results from density functional theory (DFT) calculations employing a hybrid Hamiltonian. Valence region X-ray photoelectron and K-shell X-ray emission and absorption spectra of the LnInO₃ compounds were simulated with the aid of the DFT calculations. Photoionization of lanthanide 4f orbitals gives rise to a complex final-state multiplet structure in the valence region for the 4f ⁿ compounds PrInO₃, NdInO₃, and SmInO₃, and the overall photoemission spectral profiles were shown to be a superposition of final-state 4f ^n-1 terms onto the cross-section weighted partial densities of states from the other orbitals. The occupied 4f states are stabilized in moving across the series Pr-Nd-Sm. Band gaps were measured using diffuse reflectance spectroscopy. These results demonstrated that the band gap of LaInO₃ is 4.32 eV, in agreement with DFT calculations. This is significantly larger than a band gap of 2.2 eV first proposed in 1967 and based on the idea that In 4d states lie above the top of the O 2p valence band. However, both DFT and X-ray spectroscopy show that In 4d is a shallow core level located well below the bottom of the valence band. Band gaps greater than 4 eV were observed for NdInO₃ and SmInO₃, but a lower gap of 3.6 eV for PrInO₃ was shown to arise from the occupied Pr 4f states lying above the main O 2p valence band.

Risk factors for transmission of carbapenem-resistant Enterobacterales to healthcare personnel gloves and gowns in the USA

BACKGROUND

Hospitals are sources for acquisition of carbapenem-resistant Entero-bacterales (CRE), and it is believed that the contamination of healthcare personnel (HCP) hands and clothing play a major role in patient-to-patient transmission of antibiotic-resistant bacteria.

AIM

The aim of this study was to determine which HCP types, HCP-patient interactions, and patient characteristics are associated with greater transmission of CRE to HCP gloves and gowns in the hospital.

METHODS

This was a prospective observational cohort study that enrolled patients with recent surveillance or clinical cultures positive for CRE at five hospitals in four states in the USA. HCP gloves and gown were cultured after patient care. Samples were also obtained from patients' stool, perianal area, and skin of the chest and arm to assess bacterial burden.

FINDINGS

Among 313 CRE-colonized patients and 3070 glove and gown cultures obtained after patient care, HCP gloves and gowns were found to be contaminated with CRE 7.9% and 4.3% of the time, respectively. Contamination of either gloves or gowns occurred in 10.0% of interactions. Contamination was highest (15.3%) among respiratory therapists (odds ratio: 3.79; 95% confidence interval: 1.61-8.94) and when any HCP touched the patient (1.52; 1.10-2.12). Associations were also found between CRE transmission to HCP gloves or gown and: being in the intensive care unit, having a positive clinical culture, and increasing bacterial burden on the patient.

CONCLUSION

CRE transmission to HCP gloves and gown occurred frequently. These findings may inform evidence-based policies about what situations and for which patients contact precautions are most important.

Adverse outcomes after planned surgery with anticipated intensive care admission in out-of-office-hours time periods: a multicentre cohort study

BACKGROUND

Increasing mortality for patients admitted to hospitals during the weekend is a contentious but well described phenomenon. However, it remains uncertain whether adverse outcomes, including prolonged hospital length-of-stay (LOS), may also occur after patients undergoing major planned surgery are admitted to an intensive care unit (ICU) out-of-office-hours, either during weeknights (after 18:00) or on weekends.

METHODS

All planned surgical admissions requiring admission to one of 183 ICUs across Australia and New Zealand between 2006 and 2016 were included in this retrospective population-based cohort study. Primary outcomes were hospital LOS and hospital mortality.

RESULTS

Of the total 504 713 planned postoperative ICU admissions, 33.6% occurred during out-of-office-hours. After adjusting for available risk factors, out-of-office-hours ICU admissions were associated with a significant increase in hospital LOS [+2.6 days, 95% confidence interval (CI) 2.5-2.6], mortality [odd ratio (OR) 1.5, 95%CI 1.4-1.6], and a reduced chance of being directly discharged home (OR 0.8, 95%CI 0.8-0.8). The strongest association for adverse outcomes occurred with weekend ICU admissions (hospital LOS: +3.0 days, 95%CI 3.2-3.6; hospital mortality: OR 1.7, 95%CI 1.6-1.8). Clustering of adverse outcomes by hospitals was not observed in the generalised estimating equation analyses.

CONCLUSIONS

Despite a greater clinical staff availability and higher monitoring levels, planned surgery requiring anticipated out-of-office-hours ICU admission was associated with a prolonged hospital LOS, reduced discharge directly home, and increased mortality compared with in-office-hours admissions. Our findings have potential clinical, economic and health policy implications on how complex planned surgery should be planned and managed.

The deposition of metal nanoparticles on carbon surfaces: the role of specific functional groups

The influence of hydroxyl and carbonyl groups on the deposition of gold from solution onto graphite surfaces was explored: OH gives Au⁰ whereas CO results in Au³⁺.

Deconstructing the relative benefits of a universal glove and gown intervention on MRSA acquisition

BACKGROUND

The 20-site Benefits of Universal Glove and Gown (BUGG) study found that wearing gloves and gowns for all patient contacts in the intensive care unit (ICU) reduced acquisition rates of meticillin-resistant Staphylococcus aureus (MRSA). The relative importance of gloves and gowns as a barrier, improved hand hygiene, and reduced healthcare worker (HCW)-patient contact rates is unknown.

AIM

To determine what proportion of the reduction in acquisition rates observed in the BUGG study was due to improved hand hygiene, reduced contact rates, and universal glove and gown use using agent-based simulation modelling.

METHODS

An existing agent-based model to simulate MRSA transmission dynamics in an ICU was modified, and the model was calibrated using site-specific data. Model validation was completed using data collected in the BUGG study. A full 2^k factorial design was conducted to quantify the relative benefits of improving each of the aforementioned factors with respect to MRSA acquisition rates.

FINDINGS

Across 40 simulated replications for each factorial design point and intervention site, approximately 44% of the decrease in MRSA acquisition rates was due to universal glove and gown use, 38.1% of the decrease was due to improvement in hand hygiene compliance on exiting patient rooms, and 14.5% of the decrease was due to the reduction in HCW-patient contact rates.

CONCLUSION

Using mathematical modelling, the decrease in MRSA acquisition in the BUGG study was found to be due primarily to the barrier effects of gowns and gloves, followed by improved hand hygiene and lower HCW-patient contact rates.

PdZn catalysts for CO2 hydrogenation to methanol using chemical vapour impregnation (CVI)

The formation of PdZn bimetallic alloys on ZnO, TiO₂ and Al₂O₃ supports was investigated, together with the effect of alloy formation on the CO₂ hydrogenation reaction. The chemical vapour impregnation (CVI) method produced PdZn nanoparticles with diameters of 3–6 nm. X-ray photoelectron spectroscopy and X-ray diffraction revealed the changes in the structure of the PdZn alloy that help stabilise formate intermediates during methanol synthesis. PdZn supported on TiO₂ exhibits high methanol productivity of 1730 mmol kg_cat⁻¹ h⁻¹ that is associated with the high dispersion of the supported PdZn alloy.

Predictors of early treatment discontinuation in a cohort of patients treated with boceprevir-based therapy for hepatitis C infection

In this real-world cohort, 49% of patients stopped boceprevir-based hepatitis C therapy early, with only 20% stopping due to treatment futility. Having more comorbidities was significantly associated with early discontinuation. Tolerability of boceprevir-based regimens may be substantially worse than reported in clinical trials, particularly for patients with comorbidities.

Patient factors associated with frequent clotting of dialysers during haemodiafiltration in critically ill patients: a post hoc analysis of a randomised controlled study

Continuous haemodiafiltration (CVVHDF) is the main form of renal replacement therapy in critically ill patients with severe acute kidney injury. Clotting of the dialysers during CVVHDF is frequent, because most patients with acute kidney injury have an increased risk of bleeding and cannot be systemically anticoagulated. Using data from a randomised controlled trial comparing the efficiency of CVVHDF by placing the dialysis catheter tip at the right atrium or superior vena cava, this study assessed the patient factors associated with an increased risk of frequent clotting of the dialysers-defined by >1 dialysers clotted per day of CVVHDF. Of the 94 patients included in this study, a higher body mass index, a higher platelet count and a lower International Normalized Ratio were associated with an increased risk of frequent clotting of dialysers in the univariate analyses. Use of aspirin or clopidogrel, causes of acute kidney injury and daily dose of unfractionated heparin used were not significantly associated with the risk of frequent clotting of dialysers. In the multivariate parsimony model, only a high body mass index (odds ratio 1.06 per point increment, 95% confidence interval 1.01 to 1.13; P=0.036) and a high platelet count (odds ratio 1.84 per 100x10(9)/l increment, 95% confidence interval 1.17 to 2.91; P=0.009), both in a relatively linear fashion, were independently associated with an increased risk of frequent clotting of dialysers. Optimising the position of the tip of the dialysis catheter may be particularly important for patients with a high body mass index and platelet count in order to reduce frequent clotting of dialysers during CVVHDF.

Encapsulation of Au Nanoparticles on a Silicon Wafer During Thermal Oxidation

We report the behavior of Au nanoparticles anchored onto a Si(111) substrate and the evolution of the combined structure with annealing and oxidation. Au nanoparticles, formed by annealing a Au film, appear to "float" upon a growing layer of SiO₂ during oxidation at high temperature, yet they also tend to become partially encapsulated by the growing silica layers. It is proposed that this occurs largely because of the differential growth rates of the silica layer on the silicon substrate between the particles and below the particles due to limited access of oxygen to the latter. This in turn is due to a combination of blockage of oxygen adsorption by the Au and limited oxygen diffusion under the gold. We think that such behavior is likely to be seen for other metal-semiconductor systems.

Do contact precautions cause depression? A two-year study at a tertiary care medical centre

Contact precautions, used to reduce the transmission of infectious diseases, include the wearing of gowns and gloves for room entry. Previous small studies have shown an association between contact precautions and increased symptoms of depression and anxiety. A retrospective cohort of all patients admitted to a tertiary care centre over two years was studied to assess the relationship between contact precautions and depression or anxiety. During the two-year period, there were 70,275 admissions including 28,564 unique non-intensive-care-unit (ICU), non-psychiatric admissions. After adjusting for potential confounders, contact precautions were associated with depression [odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2-1.5] but not with anxiety (OR 0.8, 95% CI 0.7-1.1) in the non-ICU population. Depression was 40% more prevalent among general inpatients on contact precautions.

Efficacy of UV light treatment for the microbiological decontamination of chicken, associated packaging, and contact surfaces

UV light was investigated for the decontamination of raw chicken, associated packaging, and contact surfaces. The UV susceptibilities of a number of Campylobacter isolates (seven Campylobacter jejuni isolates and three Campylobacter coli isolates), Escherichia coli ATCC 25922, and Salmonella enterica serovar Enteritidis ATCC 10376 in liquid media were also investigated. From an initial level of 7 log CFU/ml, no viable Campylobacter cells were detected following exposure to the most intense UV dose (0.192 J/cm(2)) in liquid media (skim milk subjected to ultrahigh-temperature treatment and diluted 1:4 with maximum recovery diluent). Maximum reductions of 4.8 and 6.2 log CFU/ml were achieved for E. coli and serovar Enteritidis, respectively, in liquid media. Considerable differences in susceptibilities were found between the Campylobacter isolates examined, with variations of up to 4 log CFU/ml being observed. UV treatment of raw chicken fillet (0.192 J/cm(2)) reduced C. jejuni, E. coli, serovar Enteritidis, total viable counts, and Enterobacteriaceae by 0.76, 0.98, 1.34, 1.76, and 1.29 log CFU/g, respectively. Following UV treatment of packaging and surface materials, reductions of up to 3.97, 4.50, and 4.20 log CFU/cm(2) were obtained for C. jejuni, E. coli, and serovar Enteritidis, respectively (P < 0.05). Overall, the color of UV-treated chicken was not significantly affected (P ≥ 0.05). The findings of this study indicate that Campylobacter is susceptible to UV technology and that differences in sensitivities exist between investigated isolates. Overall, UV could be used for improving the microbiological quality of raw chicken and for decontaminating associated packaging and surface materials.

Use of Isotonic Sodium Bicarbonate to Prevent Radiocontrast Nephropathy in Patients with Mild Pre-Existing Renal Impairment: A Meta-Analysis

Acute renal dysfunction after radiocontrast in patients with pre-existing renal impairment is not uncommon and is associated with significant morbidity and mortality. Isotonic sodium bicarbonate solution was first reported to reduce radiocontrast nephropathy in 2004. This first study was, however, limited by its small sample size and as such, the use of isotonic sodium bicarbonate to prevent radiocontrast nephropathy is still not widely used by many anaesthetists and intensivists. We meta-analysed relevant randomised controlled studies sourced from the Cochrane Controlled Trial Register (2007 issue 4), EMBASE and MEDLINE databases (1966 to April 15, 2008) without any language restriction. The use of isotonic sodium bicarbonate was associated with a significant reduction in risk of an incremental rise in serum creatinine concentration 25% above baseline (relative risk 0.22, 95% confidence interval [CI]: 0.11 to 0.44, P <0.0001; I 2 =0%>) and had a protective effect on the absolute change in serum creatinine concentration (weighted-mean-difference -9.4 μmol/l, 95% CI: -17.2 to -1.7, P=0.02; I 2 =0%>) and creatinine clearance (weighted-mean-difference 3.7 ml/min, 95% CI: 0.55 to 6.80, P=0.02; I 2 =57.1%) after radiocontrast. The incidence of acute renal failure requiring dialysis was low (1.4%) and was not significantly different after the use of isotonic sodium bicarbonate (relative risk 0.59, 95% CI: 0.15 to 2.42, P=0.47; I 2 =0%). With the limited data available, isotonic sodium bicarbonate appears to be safe and very effective in reducing radiocontrast nephropathy in patients with mild pre-existing renal impairment. A large randomised controlled study is needed to confirm whether isotonic bicarbonate can improve patient centred clinical outcomes.

Effect of low temperatures (-18 to +5°C) on the texture of beef lean

The textural properties of beef over the temperature range -18 to +5°C were measured using Warner Bratzler (WB) and tensile techniques. In addition, the effects of rapid radio frequency (RF) tempering and slower conventional air tempering on texture were compared. Temperature showed a significant effect (P<0.05) on WB and tensile shear force, with higher values obtained at temperatures on or below -5°C. Work to fracture values showed two peaks at -15 and -3°C. Sample thickness and muscle fibre direction were also important factors affecting shear force, with samples cut across fibres showing higher values. Tempering method showed no effect (P⩾0.05) on the textural properties measured. In light of the rapid nature of RF tempering, these findings will be of interest to the meat industry.

Is laparoscopically assisted radical vaginal hysterectomy for cervical carcinoma safe? A case control study with follow up

OBJECTIVE

To compare a new surgical approach, laparoscopically assisted radical vaginal hysterectomy (LARVH) with open radical hysterectomy in women with cervical cancer. Can selected women benefit from the minimally invasive approach without compromising safety (recurrence rate) and morbidity (complications)?

DESIGN

Retrospective case control study.

SETTING

A tertiary referral unit for gynaecological malignancies.

POPULATION

Thirty women undergoing LARVH were included and compared with 30 women undergoing open radical surgery. The control group was matched for age, body mass index and disease stage.

METHODS

Retrospective collection of data from patient files and follow up.

MAIN OUTCOME MEASURES

Recurrence rate, complication rate, hospital stay, nodal counts, blood loss, operating time.

RESULTS

Recurrence rates were equal (6.7%). There was one death, in the LARVH group. Follow up was mean 31 months in the LARVH group and 30.9 months in the open group. Blood loss as measured by mean drop in haemoglobin was greater in the open group (2.03 versus 3.01 g/dl, P = 0.02). Transfusions were given in 40% of women in the open group and 16.7% in the LARVH group. Hospital stay was significantly less in the LARVH group (5.9 versus 7.8 nights, P = 0.003). Mean operating time was longer in the LARVH group (131 versus 187 minutes P = 0.0001). Mean nodal counts did not differ significantly (17.4 in open vs 14.8 in LARVH, P > 0.05). There were seven perioperative complications in the open group and four in the LARVH group. There have been two recurrences in each group (6.67%) at mean follow up of 31 (LARVH) and 30.9 (open) months.

CONCLUSIONS

The first 30 LARVH procedures performed in this unit are comparable in terms of safety (recurrence rate and complication rate) and economic factors (shorter hospital stay mitigating longer operating time). Further development of this technique is warranted.

The effects of cardiopulmonary bypass on plasma concentrations and protein binding of methohexital and thiopental

The effects of cardiopulmonary bypass (CPB) on plasma concentrations and protein binding of methohexital and thiopental were studied during continuous infusions in two groups of ten cardiac surgical patients. Patients were administered an infusion regimen designed to produce a stable total plasma concentration at 5 mg/L for methohexital and 10 mg/L for thiopental. Prior to the commencement of CPB the mean (+/-SD) total plasma methohexital concentration was 5.00 +/- 0.69 mg/L. This fell to 3.12 +/- 0.89 mg/L at two minutes after commencement of CPB, and rose to 4.67 +/- 1.11 mg/L by 75 minutes after commencement of CPB. The unbound fraction rose from 27.1 +/- 5.1% to 42.8 +/- 9.2% at five minutes after the start of CPB, and gradually decreased to 32.1 +/- 4.9% by 75 minutes. The unbound concentration (1.37 +/- 0.32 mg/L) was unaffected by the onset of CPB, being 1.51 +/- 0.49 mg/L at 75 minutes after the start of CPB. Thiopental followed a similar pattern to methohexital, with the total plasma thiopental concentration falling from 9.22 +/- 0.73 mg/L to 4.90 +/- 0.83 mg/L at two minutes after commencement of CPB, and rising again to 7.13 +/- 1.03 mg/L 75 minutes later. During the same period the unbound fraction of thiopental rose from 16.1 +/- 2.5% to 30.3 +/- 7.3% five minutes after the start of CPB, and fell gradually to 22.8 +/- 5.8% after 75 minutes. The unbound concentration (1.51 +/- 0.21 mg/L) was again unchanged by the onset of CPB, being 1.71 +/- 0.29 mg/L at 75 minutes. Plasma protein binding of both drugs correlated strongly with plasma albumin concentration, which decreased by 40% during CPB. It is concluded that hemodilution caused the reduction in total drug concentration and protein binding at the onset of CPB, but that the decrease in protein binding counteracted the dilution of unbound drug, resulting in a stable unbound concentration throughout CPB, and that this effect may be common for barbiturates.

Levels of serum chemokines discriminate clinical myelopathy associated with human T lymphotropic virus type 1 (HTLV-1)/tropical spastic paraparesis (HAM/TSP) disease from HTLV-1 carrier state

Approximately 5% of people infected with human T lymphotropic virus type 1 (HTLV-1) develop clinical myelopathy or tropical spastic paraparesis (HAM/TSP) that is associated with high-levels of Th1 cytokines, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha. Chemokines are known to induce cytokine secretion and direct the trafficking of immune cells to sites of disease. The present study measured serum chemokines correlated with autonomously released IFN-gamma in cell cultures. HTLV-1 infection was defined by enzyme-linked immunosorbent assay (ELISA) and confirmed by Western blot. Subjects included HTLV-1 carriers (n = 56), patients with HAM/TSP (n = 31) and healthy HTLV-1 seronegative volunteer controls (n = 20). Serum chemokines and IFN-gamma autonomously released by mononuclear cells in culture were quantified by ELISA. Compared to HTLV-1 carriers, serum chemokines in HAM/TSP patients showed significantly increased levels of CXCL9 and CXCL10, significantly diminished levels of CCL2 and similar amounts of CCL11 and CCL24. In contrast, CCL11 and CCL24 were significantly lower in serum of HAM/TSP patients than either control. IFN-gamma was positively correlated with CXCL9 and CXCL10 when HAM/TSP and HTLV-1 carriers were used as a combined group. However, despite a large proportion of HTLV-1 carriers having high IFN-gamma levels, these chemokines were not increased in carriers. This study showed that high levels of CXCL9 and CXCL10 in the systemic circulation and low serum CCL2 levels are features of HAM/TSP. HTLV-1 infection and Tax and/or additional viral encoded factor-mediated pathological processes triggering T cell activation with autogenous IFN-gamma release are probably involved in regulating chemokine release.

Relation between Gram-stain and clinical criteria for diagnosing bacterial vaginosis with special reference to Gram grade II evaluation

The aim of this study was to analyse how the results of Gram-staining vaginal smears correlated with the clinical criteria for determining the existence of bacterial vaginosis (BV) and, in particular, how the category defined as 'intermediate' or Gram grade II did so and its significance. Women attending an antenatal clinic with an abnormal vaginal flora, that is those who had Gram-stains of grades II or III, the latter considered to equate with BV, were given clindamycin or a placebo intravaginally and examined again on up to three occasions. Gram-stain readings of grade III correlated with the clinical criteria for BV on 356 (91.7%) of 388 occasions. Grade II readings covered the spectrum of clinical criteria and correlated with those for BV on 35 (37.2%) of 94 occasions. Grade I, recorded 231 times and seen usually after clindamycin treatment, was associated with BV only once. The sensitivity, specificity, positive predictive value and negative predictive value of the Gram stain for the diagnosis of BV, based on a combination of grades II and III, were 99.7%, 71.6%, 81% and 99.6%, respectively; based on grade III only, the values were 99.7%, 87.7%, 91.6% and 99.6%, respectively. Women reported a malodorous vaginal discharge on 49.2% of the occasions a grade III flora was seen and 13.3% of the times grade II was recorded. It was not associated with grade I and would seem a useful adjunct to the accepted clinical criteria for diagnosing BV. Each of the clinical criteria was found in about equal proportions (87%-91%) for women whose Gram grade was III. For grade II, an increased discharge was noted most often (76.5%) and 'clue' cells least often (24.5%). A positive amine test was the most specific, being associated with <1% of grade I smears. Of women with grade III status, 91% reverted to grade I after treatment with clindamycin for three days. In contrast, of women with grade II status, 53% reverted to grade I, as did 47% of those who were given a placebo. The 'intermediate' (grade II) category is a Gram-stain diagnosis and not one that can be made clinically. It is important to recognize as a distinct entity not only because amalgamation with grade III diminishes the specificity and positive predictive value of the Gram-stain for diagnosing BV, but also because women of grade II status usually fail to respond to clindamycin treatment, whereas those of grade III do not.

Seasonal flight activity of two Homalodisca species (Homoptera: Cicadellidae) that spread Xylella fastidiosa in southern California

Homalodisca coagulata (Say) and Homalodisca lacerta (Fowler) are vectors of a new bacterial disease of oleander in California known as oleander leaf scorch, induced by the bacterium Xylella fastidiosa. H. coagulata also has been implicated in the spread of the strain of X. fastidiosa that induces Pierce's disease of grapevines in California. We monitored the flight activity of H. coagulata and H. lacerta in oleander and citrus by using yellow sticky cards at three southern California locations where outbreaks of oleander leaf scorch have been documented, and where vector compliments are different. Areas sampled included a mesic coastal area (Irvine, CA) that supports predominantly H. coagulata and few H. lacerta, a dry inland location (Palm Desert, CA) that supports predominantly H. lacerta and few H. coagulata, and an intermediate area (Riverside, CA) supporting both Homalodisca species. From November 1996 to October 1999 peak catches of both Homalodisca species occurred during the midsummer at all locations. H. coagulata was trapped in greater numbers in citrus than in oleander at both the Riverside and the Irvine sites. Likewise, H. lacerta in Riverside was more associated with citrus than oleander, yet H. lacerta in Palm Desert was trapped in greater numbers in oleander than citrus.

A prospective randomised trial to compare the efficacy and safety of hemabate and syntometrine for the prevention of primary postpartum haemorrhage

In a prospective, open-label, assessor-blind, randomised parallel group study the efficacy and safety of Hemabate (Pharmacia-Upjohn Pharmaceuticals, Milton Keynes, Buckinghamshire) an analogue of 15-methyl-prostaglandin (PGF2alpha) analogue was compared with Syntometrine (Alliance Pharmaceuticals, Chippenham, Wilts) the standard combination of ergometrine and syntocinon used for the active management of the third stage of labour and the prevention of primary postpartum haemorrhage (PPH). The study was set in a district general hospital with approximately 4,000 deliveries annually. The study was discontinued at the time of the interim analysis because of unacceptable gastrointestinal side effects. At the time of the interim analysis, a total of 529 women had completed the study with 263 randomised to receive PGF2alpha and 266 to receive ergometrine and syntocinon. In a pre-specified subgroup analysis, women delivered vaginally were further subdivided into those considered to be at high or low risk of primary PPH. The measured blood loss and incidence of PPH was similar in both treatment groups whether delivered by caesarean section or vaginally independent of whether women were considered to be at high or low risk. Adverse gastrointestinal events were recorded more often in the Hemabate group. The most common symptom was diarrhoea which occurred in 21% of women who received Hemabate compared to only 0.8% of Syntometrine users. PGF2alpha is as effective as Syntometrine in the prophylaxis of primary PPH in all groups studied but there was a statistically significantly increased risk of diarrhoea among users of PGF2alpha.

Identification of Pneumocystis carinii in the lungs of infants dying of sudden infant death syndrome

BACKGROUND

Recently Pneumocystis carinii has been identified in a significant number of infants diagnosed as having died from sudden infant death syndrome (SIDS) in South America and Europe.

METHODS

We examined lung sections of 79 infants who died with a diagnosis of SIDS in Rochester, NY, and Connecticut for the presence of P. carinii.

RESULTS

Organisms with a characteristic silver stain appearance for P. carinii were identified in 14% of the lung sections.

CONCLUSIONS

These data suggest that a possible link between some cases of SIDS and infection with P. carinii should be further evaluated and that infection of young infants may serve as an important reservoir for human P. carinii.

Neurological and neuropathologic heterogeneity in two brothers with cobalamin C deficiency

Two adult brothers, one documented to have methylmalonic acidemia with homocystinuria, or cobalamin C deficiency, after autopsy, displayed severe but divergent neurological presentations. One exhibited a myelopathy and the other chronic endocrine problems (Schmidt's syndrome) followed by a neuropsychiatric and dementing disorder owing to cerebral perivascular demyelination. The recognition of cobalamin C deficiency has practical implications because it is one of the few inherited diseases of central white matter that is treatable.

Phase I and pharmacokinetic study of photodynamic therapy for high-grade gliomas using a novel boronated porphyrin

PURPOSE

To determine the recommended dose, toxicity profile, and pharmacokinetics of a novel boronated porphyrin (BOPP) for photodynamic therapy (PDT) of intracranial tumors.

PATIENTS AND METHODS

BOPP was administered alone in increasing doses (0.25, 0.5, 1.0, 2.0, 4.0, or 8.0 mg/kg) preoperatively in patients with intracranial tumors undergoing postresection PDT until dose-limiting toxicity (DLT) was observed.

RESULTS

Twenty-nine assessable patients with intracranial tumors received BOPP intravenously 24 hours before surgery. The recommended dose was 4 mg/kg. Dose escalation was limited by thrombocytopenia. The most common nonhematologic toxicity was skin photosensitivity. Pharmacokinetic parameters showed increased area under the plasma concentration-time curve and maximum concentration with increased dose. Tumor BOPP concentrations also increased with increased dose.

CONCLUSION

BOPP at a dose of 4 mg/kg was well tolerated. DLT was thrombocytopenia, and photosensitivity was the only other toxicity of note. The efficacy of PDT using BOPP requires further exploration.

Neonatal hepatic drug elimination

After the transition from in utero to newborn life, the neonate becomes solely reliant upon its own drug clearance processes to metabolise xenobiotics. Whilst most studies of neonatal hepatic drug elimination have focussed upon in vitro expression and activities of drug-metabolising enzymes, the rapid physiological changes in the early neonatal period of life also need to be considered. There are dramatic changes in neonatal liver blood flow and hepatic oxygenation due to the loss of the umbilical blood supply, the increasing portal vein blood flow, and the gradual closure of the ductus venosus shunt during the first week of life. These changes which may well affect the capacity of neonatal hepatic drug metabolism. The hepatic expression of cytochromes P450 1A2, 2C, 2D6, 2E1 and 3A4 develop at different rates in the postnatal period, whilst 3A7 expression diminishes. Hepatic glucuronidation in the human neonate is relatively immature at birth, which contrasts with the considerably more mature neonatal hepatic sulfation activity. Limited in vivo studies show that the human neonate can significantly metabolise xenobiotics but clearance is considerably less compared with the older infant and adult. The neonatal population included in pharmacological studies is highly heterogeneous with respect to age, body weight, ductus venosus closure and disease processes, making it difficult to interpret data arising from human neonatal studies. Studies in the perfused foetal and neonatal sheep liver have demonstrated how the oxidative and conjugative hepatic elimination of drugs by the intact organ is significantly increased during the first week of life, highlighting that future studies will need to consider the profound physiological changes that may influence neonatal hepatic drug elimination shortly after birth.

Right heart failure impairs hepatic elimination of p-nitrophenol without inducing changes in content or latency of hepatic UDP-glucuronosyltransferases

Congestive heart failure has been shown to affect oxidative drug metabolism, however, there has been little study of its effects on drug conjugation. Using the isolated perfused livers from rats with right ventricular failure (RVF) due to pulmonary artery constriction, we studied the effects of RVF on hepatic elimination of p-nitrophenol (PNP) under controlled flow and oxygen delivery conditions. Hepatic clearance of the drug was found to be significantly impaired in RVF as compared with the sham group (0.80 +/- 0.23 versus 1.28 +/- 0.26 ml/min/g of liver). The impairment of PNP clearance in RVF occurred in parallel with significant reduction in metabolic formation clearance of p-nitrophenyl-beta-D-glucuronide; the major metabolite of PNP (0.51 +/- 0.12 versus 1.03 +/- 0.26 ml/min/g of liver). The intrinsic drug-glucuronidation capacity of livers was evaluated by measuring the microsomal content and activity of the UDP-glucuronosyltransferase(s) (UDP-GT) toward p-nitrophenol. There was no significant difference between sham and the RVF groups in either the content or the activity of the UDP-GT. The latency of the UDP-GT enzymes in microsomes was measured and was found to be similar between the two groups. The results of this study show that RVF impairs hepatic elimination of PNP and that this appears to be independent of changes in hepatic perfusion and oxygenation or alterations in hepatic content, activity, and latency of the UDP-GT.

Self-tolerance and the composition of T cell repertoire

T cell recognition of self-major histocompatibility complex-peptide complexes dictates the composition of the T cell receptor repertoire. Research projects in our laboratory deal with the mechanisms that regulate the composition of the repertoire specific for self-antigens and the defects that can result in autoimmunity. Two different types of disease models are under investigation: juvenile (type I) diabetes and cancer. Both of these diseases are impacted by the presence of anti-self CD8 cells, yet in opposite ways. By understanding the mechanisms of peripheral tolerance and the reasons they fail in autoimmunity, we may learn how to prevent undesirable autoimmunity and how to encourage an autoimmune response when it is needed to eliminate tumor cells.

Impaired elimination of propranolol due to right heart failure: drug clearance in the isolated liver and its relationship to intrinsic metabolic capacity

It is unclear if reduced hepatic drug elimination in congestive heart failure is primarily due to impairment of enzyme function as a result of tissue hypoxia, to the direct effects of hepatic congestion, or to changes intrinsic to the liver, such as reductions in enzyme content and activity. We therefore compared propranolol clearance in perfused rat livers from animals with right ventricular failure (RVF) with that from control animals. Despite the fact that both groups were perfused at comparable flow rates, perfusion pressures, and levels of oxygen delivery, hepatic extraction of propranolol was significantly reduced in RVF livers (0.688 +/- 0.122 versus 0.991 +/- 0.006 ml/min/g of liver in controls, P <.001). This effect was reflected in a 97% reduction in propranolol intrinsic clearance in RVF livers (5 +/- 4 versus 172 +/- 82 ml/min/g of liver in controls, P <.01). In RVF livers, total hepatic CYP expression was reduced by 19% compared with controls, whereas cytochrome P450 isoenzymes 1A1/2 and 2D1 were reduced by 41 and 26%, respectively. Despite the 97% reduction in propranolol intrinsic clearance in perfused RVF liver, intrinsic clearance in microsomal preparations from the same livers was reduced by only 48% compared with controls (P <.05). These findings suggest that impaired propranolol clearance in RVF is not primarily accounted for by reduced hepatic oxygen delivery or by changes in hepatic content and activity of drug-metabolizing enzymes.

Prevalence of bacterial vaginosis in women attending one of three general practices for routine cervical cytology

A prospective observational study of asymptomatic women from three different general practices was set up to establish the incidence of bacterial vaginosis (BV). The study group comprised 287 women recalled to their general practitioner's surgery for routine cervical smears. The prevalence of an abnormal vaginal flora was about the same in women attending the 3 practices. Nearly 14% of women had abnormal vaginal flora and about 9% had BV on gram stain examination of vaginal secretions. This was 2-3 times more common than findings consistent with vaginal candidiasis (3.8%). Significant numbers of women with BV had received antifungal therapy suggesting a misdiagnosis. Because of its potential complications, women should be offered screening for BV in a well-women setting and, if found, should be treated if symptomatic or at risk of adverse obstetric or gynaecological sequelae.

The resolution of Californian populations of Liriomyza huidobrensis and Liriomyza trifolii (Diptera: Agromyzidae) using PCR

Liriomyza trifolii (Burgess) and Liriomyza huidobrensis (Blanchard) are important vegetable pests in California. Populations of each species differ in their impact in central and southern regions. This difference may be explained by geographical or host plant differences in each of the regions. We used random amplified polymorphic DNA polymerase chain reactions to assess genetic differences between two laboratory populations of each species collected from central and southern California. Individual L. trifolii from the two regions could be discriminated by the presence/absence of PCR products. No such qualitative differences were apparent in PCR products amplified from L. huidobrensis individuals, but the origins of individuals could be differentiated using a bootstrap analysis of marker frequencies. Marker primers were used to compare field and laboratory individuals. No evidence was found for the existence of further populations or of hybrid populations in central and southern California. The distribution of populations of L. huidobrensis was explained completely by geographical differences. As a consequence of the absence of leafminer infestations on the same host plant varieties in both regions, factors governing L. trifolii population distribution differences were less apparent. The presence of the same host plant varieties at both sites suggests that the two L. trifolii populations differ in host plant preference.

Neonatal hepatic propranolol elimination: studies in the isolated perfused neonatal sheep liver

Using the isolated perfused neonatal sheep liver model, we examined the disposition of propranolol (n = 8, age 0.25-10 days) and compared our findings with our previous study from the perfused near-term fetal sheep liver (Ring JA, et al. 1995. Drug Metab Dispos 23:190-196). Within 45 min of dosage, perfusate propranolol levels had fallen by three orders of magnitude to be less than the limit of detection. Perfusate disappearance curves were monoexponential in six experiments and biexponential in two experiments. The mean shunt-corrected hepatic extraction ratio was 0.92 +/- 0.09, much greater than that seen in the fetal sheep liver (0.26 +/- 0.13, P < 0.0001) but still less than values in the adult sheep (0.97). At the conclusion of the perfusion, 4-hydroxypropranolol was the major metabolite present and 5-hydroxypropranolol and N-desisopropylpropranolol were minor metabolites. We conclude that the isolated perfused neonatal sheep liver is a useful model with which to study the maturation of neonatal hepatic drug oxidation. Our study shows that propranolol is rapidly eliminated by the neonatal liver to form several metabolites at rates far greater than in the fetal liver, but rates of elimination have not yet reached that reported in the adult sheep liver.

Characterization of CD8+ T lymphocytes that persist after peripheral tolerance to a self antigen expressed in the pancreas

As a result of expression of the influenza hemagglutinin (HA) in the pancreatic islets, the repertoire of HA-specific CD8+ T lymphocytes in InsHA transgenic mice (D2 mice expressing the HA transgene under control of the rat insulin promoter) is comprised of cells that are less responsive to cognate Ag than are HA-specific CD8+ T lymphocytes from conventional mice. Previous studies of tolerance induction involving TCR transgenic T lymphocytes suggested that a variety of different mechanisms can reduce avidity for Ag, including altered cell surface expression of molecules involved in Ag recognition and a deficiency in signaling through the TCR complex. To determine which, if any, of these mechanisms pertain to CD8+ T lymphocytes within a conventional repertoire, HA-specific CD8+ T lymphocytes from B10.D2 mice and B10.D2 InsHA transgenic mice were compared with respect to expression of cell surface molecules, TCR gene utilization, binding of tetrameric KdHA complexes, lytic mechanisms, and diabetogenic potential. No evidence was found for reduced expression of TCR or CD8 by InsHA-derived CTL, nor was there evidence for a defect in triggering lytic activity. However, avidity differences between CD8+ clones correlated with their ability to bind KdHA tetramers. These results argue that most of the KdHA-specific T lymphocytes in InsHA mice are not intrinsically different from KdHA-specific T lymphocytes isolated from conventional animals. They simply express TCRs that are less avid in their binding to KdHA.

Effect of intravaginal clindamycin cream on pregnancy outcome and on abnormal vaginal microbial flora of pregnant women

OBJECTIVES

To determine whether intravaginal clindamycin cream reduces the incidence of abnormal pregnancy outcome in women with abnormal vaginal microbial flora graded as intermediate or BV and to investigate the effect of the antibiotic on vaginal microbial flora.

METHODS

A prospective cohort study of pregnant women in an antenatal clinic of a district general hospital. The subjects were 268 women who had abnormal vaginal microbial flora at first clinic visit by examination of a Gram-stained vaginal smear and 34 women with a normal vaginal flora. Two hundred and thirty-seven women were evaluable. Women with abnormal Gram-stained smears (graded as II or III) on clinic recall were randomised to receive treatment (intravaginal clindamycin cream) or placebo and followed to assess outcome of pregnancy, vaginal flora, and detection of Mycoplasma hominis and Ureaplasma urealyticum after treatment.

RESULTS

Abnormal outcomes of pregnancy were not significantly different in treated and placebo groups by Chi square (P = 0.2). However, women with grade III flora responded better to clindamycin than women with grade II flora by numbers of abnormal outcomes (P = 0.03) and return to normal vaginal flora (P = 0.01) (logistic regression analysis model). This may be due to differences in vaginal bacterial species in these grades. Women whose abnormal vaginal flora had spontaneously returned to normal on follow-up and were therefore not treated (revertants) had as many abnormal outcomes as placebos suggesting that damage by abnormal bacterial species occurred early in pregnancy.

CONCLUSIONS

Gram-stain screening distinguishing grade II from grade III flora may be helpful in prescribing treatment other than clindamycin for women with grade II flora. Earlier diagnosis and treatment may be more effective in preventing an abnormal outcome, possibly as soon as pregnancy is diagnosed or even offered as a pre-conception screen.

Conjugation of para-nitrophenol by the isolated perfused neonatal sheep liver

We examined the metabolism of para-nitrophenol (PNP) in the isolated perfused neonatal sheep liver (n = 8, 0.25-11 days) and compared the findings with our previous data from the perfused near-term fetal sheep liver (Ring, J. A., et al. Drug Metab Dispos 1996, 24, 1378). A three-step dosage regimen was used (72, 144, and 288 micromol of PNP). At the end of each dosage phase, PNP had fallen below detectable levels, and 101 +/- 16% of the dose was accounted for as PNP conjugates. Elimination of PNP from perfusate varied with dose. Elimination was first order with the 72-micromol dose; with the 144-micromol dose, elimination was first order in four livers but Michaelis-Menten kinetics in the remaining four. With all the 288-micromol doses, elimination was Michaelis-Menten and gave the following biochemical parameters: K(m) = 255 +/- 138 microM (fetal = 14.7 microM, P < 0.01), V(max) = 515 +/- 285 nmol/min/g liver (fetal = 34.3 nmol/min/g liver, P < 0.01), and intrinsic hepatic clearance = 2.36 +/- 1.21 mL/min/g liver (fetal = 4.74 mL/min/g liver, P > 0. 05). The mean shunt-corrected hepatic extraction ratio of PNP was 0. 82 (range, 0.40-1.0) and strongly correlated with neonatal age (r = 0.90, P < 0.05). We conclude that PNP is highly extracted by the isolated perfused neonatal sheep liver at much higher efficiency than in the near-term fetal sheep, reflecting a maturation of conjugation that progresses further in the early neonatal period.

Fetal hepatic drug elimination

The majority of studies of fetal hepatic elimination have concentrated on the expression and activity of the metabolizing enzymes, but the unique physiologic milieu of the fetal liver should also be considered. The basic structure of the liver is formed by the end of the first trimester. The fetal hepatic circulation differs substantially from that of the adult in that there is an extra input vessel, the umbilical vein, and there is shunting of 30-70% of hepatic blood flow via the ductus venosus. The left and right lobes of the fetal liver seem to function independently with respect to a variety of biochemical parameters, due at least in part to the lower oxygen supply to the right lobe. The zonation of drug-metabolizing enzymes along the hepatic acinus, which is prominent in the adult liver, is absent in the fetal liver. Unlike rodent species, the human fetal liver has a significant capacity for drug metabolism. Of the oxidative enzymes, CYP3A7 accounts for up to 50% of total fetal hepatic cytochrome P450 content. Expression of this enzyme decreases dramatically after birth. CYP1A1 and CYP2D6 have also been detected in human fetal liver, but whether CYP2E1 is expressed remains controversial. Several other cytochrome P450s have been identified and await characterization. Fetal hepatic drug conjugation may prolong fetal exposure to the metabolites produced, which, being more water soluble, do not readily cross the placenta back to the mother and, if excreted in fetal urine, can be recycled in the fetus via amniotic fluid and fetal swallowing. Limited activity of glucuronidation enzymes has been demonstrated in human fetal liver in contrast to the activity of sulfation enzymes, which is significant. Limited in vivo studies in fetal sheep have demonstrated significant fetal hepatic drug elimination, and this has been confirmed in studies of the isolated perfused fetal sheep liver. Our understanding of fetal hepatic elimination processes has advanced steadily over the years. Future developments, however, should consider more fully the influence of the unique physiological milieu of the fetal liver, in addition to the expression and activity of drug metabolizing enzymes.