Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

GENE-47. A 3D ATLAS TO EVALUATE THE SPATIAL PATTERNING OF GENETIC ALTERATIONS AND TUMOR CELL STATES IN GLIOMA

BACKGROUND

Previous studies of solid tumors have been restricted in their ability to map how heterogeneous cell populations evolved within the tumor in three-dimensional (3D) space due to insufficient sampling, typically one sample per tumor, and a lack of knowledge of where within the tumor the sample was obtained. Knowledge of the extensivity of heterogeneity and how it is spatially distributed is crucial for assessing whether a therapeutic target is truly tumor-wide, and for exploring how mutations relate to heterogeneity in the local microenvironment.

METHODS

We developed a novel platform to integrate and visualize in 3D multi-omics data generated from each of 8–10 spatially mapped samples per tumor. Together, the 171 samples collected using this approach from 16 adult diffuse glioma at diagnosis and recurrence form a novel resource – the 3D Glioma Atlas.

RESULTS

By maximally sampling the tumor geography without excluding samples based on low cancer cell fraction (CCF), we identify a subpopulation of glioblastoma with pervasively lower CCF likely excluded by other atlases, such as the TCGA, that used stringent CCF cutoffs. Exome sequencing of 3D-mapped samples from lower-grade tumors revealed that clonal expansions are typically spatially segregated, implying minimal tumor-wide intermixing of genetically heterogenous cells. Heterogeneity is less spatially segregated for faster-growing high-grade tumors, suggesting that cell populations expand in these tumors differently. Recurrent low-grade tumors have greater intratumoral mutational heterogeneity than newly diagnosed tumors, though this did not translate into greater dissimilarity in gene expression profiles for recurrent tumors, suggesting minimal functional impact of this additional mutational diversity on gene expression.

CONCLUSIONS

The delineation of spatial patterns of heterogeneity that our work provides enables more informed interpretation of biopsies and greater insight into the factors shaping intratumoral variation of gene expression patterns. Ongoing work is exploring the spatial patterning of amplification events and the tumor microenvironment.

OS12.4 In vivo dynamics and targeting of vessel co-option in glioma

BACKGROUND

Gliomas comprise heterogeneous malignant glial and stromal cells. While blood vessel co-option is a potential mechanism to escape anti-angiogenic therapy, the relevance of glial phenotype in this process is unclear.

MATERIAL AND METHODS

Here, we intravitally study preclinical syngenetic models of glioma as well as patient-derived cells transplanted orthotopically. Moreover, we profoundly confirm our preclinical results with histological studies on patient specimens.

RESULTS

We show that Olig2+ oligodendrocyte precursor-like glioma cells invade by single-cell vessel co-option and preserve the blood-brain barrier (BBB). Conversely, Olig2-negative glioma cells form dense perivascular collections and promote angiogenesis and BBB breakdown, leading to innate immune cell activation. Experimentally, Olig2 promotes Wnt7b expression, a finding that correlates in human glioma profiling. Targeted Wnt7a/7b deletion or pharmacologic Wnt inhibition blocks Olig2+ glioma single-cell vessel co-option and enhances responses to temozolomide. Finally, Olig2 and Wnt7 become upregulated after anti-VEGF treatment in preclinical models and patients.

CONCLUSION

Here, we show that glioma is able to employ vessel co-option, i.e. the movement of tumor cells towards and along the pre-existing vasculature.

Glioma oligodendrocyte-like (OPCL) cells express Wnt7 that is necessary for vessel co-option and Wnt inhibitors significantly improve survival with temozolomide. Moreover, we demonstrated that anti-VEGF-treatment of glioma selects for Olig2/Wnt7+ cells

A multiphase model for three-dimensional tumor growth

Several mathematical formulations have analyzed the time-dependent behaviour of a tumor mass. However, most of these propose simplifications that compromise the physical soundness of the model. Here, multiphase porous media mechanics is extended to model tumor evolution, using governing equations obtained via the Thermodynamically Constrained Averaging Theory (TCAT). A tumor mass is treated as a multiphase medium composed of an extracellular matrix (ECM); tumor cells (TC), which may become necrotic depending on the nutrient concentration and tumor phase pressure; healthy cells (HC); and an interstitial fluid (IF) for the transport of nutrients. The equations are solved by a Finite Element method to predict the growth rate of the tumor mass as a function of the initial tumor-to-healthy cell density ratio, nutrient concentration, mechanical strain, cell adhesion and geometry. Results are shown for three cases of practical biological interest such as multicellular tumor spheroids (MTS) and tumor cords. First, the model is validated by experimental data for time-dependent growth of an MTS in a culture medium. The tumor growth pattern follows a biphasic behaviour: initially, the rapidly growing tumor cells tend to saturate the volume available without any significant increase in overall tumor size; then, a classical Gompertzian pattern is observed for the MTS radius variation with time. A core with necrotic cells appears for tumor sizes larger than 150 μm, surrounded by a shell of viable tumor cells whose thickness stays almost constant with time. A formula to estimate the size of the necrotic core is proposed. In the second case, the MTS is confined within a healthy tissue. The growth rate is reduced, as compared to the first case - mostly due to the relative adhesion of the tumor and healthy cells to the ECM, and the less favourable transport of nutrients. In particular, for tumor cells adhering less avidly to the ECM, the healthy tissue is progressively displaced as the malignant mass grows, whereas tumor cell infiltration is predicted for the opposite condition. Interestingly, the infiltration potential of the tumor mass is mostly driven by the relative cell adhesion to the ECM. In the third case, a tumor cord model is analyzed where the malignant cells grow around microvessels in a 3D geometry. It is shown that tumor cells tend to migrate among adjacent vessels seeking new oxygen and nutrient. This model can predict and optimize the efficacy of anticancer therapeutic strategies. It can be further developed to answer questions on tumor biophysics, related to the effects of ECM stiffness and cell adhesion on tumor cell proliferation.

4-(1,3-Dimethoxyprop-2-ylamino)-2,7-dimethyl-8-(2, 4-dichlorophenyl)pyrazolo[1,5-a]-1,3,5-triazine: a potent, orally bioavailable CRF(1) receptor antagonist

Structure-activity studies in the pyrazolo[1,5-a]-1,3,5-triazine series led to the discovery that compound 11i (DMP696) is a potent hCRF(1) receptor antagonist (K(i) = 1.7 nM vs 7.5 nM for alpha-hel-CRF(9-41), hCRF(1) adenylate cyclase IC(50) = 82 nM vs 286 nM for alpha-hel-CRF(9-41)). Compound 11i has excellent oral pharmacokinetic profiles in rats and dogs (37% and 50% oral bioavailabilities, respectively). This compound displays good activity in the rat situational anxiety model (MED = 3 mg/kg (po)), whereas a literature standard 1 (CP154526-1) was inactive (MED > 30 mg/kg (po)). Analogue 11i reduced stereotypical mouth movements in rhesus monkeys by 50% at 21 mg/kg (po) using the human intruder paradigm. Overall, the profile of pyrazolotriazine 11i indicates that hCRF(1) receptor antagonists may be anxiolytic agents, which have reduced motor side effect profiles.

Pharmacodynamics of trovafloxacin in experimental pneumococcal meningitis: basis for dosage selection in children with meningitis

Trovafloxacin is a recently approved fluoroquinolone with excellent activity against gram-positive and gram-negative organisms that offers a potential alternative for treatment of beta-lactam-resistant pneumococcal meningitis. Using the rabbit meningitis model, we sought to characterize the pharmacodynamic properties of trovafloxacin in the cerebrospinal fluid (CSF). Animals were given single doses of trovafloxacin of 10, 15, 20 or 30 mg/kg; 1 h after Infusion mean CSF concentrations were 0.59+/-0.18, 0.74+/-0.14, 1.12+/-0.12 and 1.07+/-0.35 mg/L, respectively. The bacterial killing rate Increased with increasing dosages of trovafloxacin, indicating that its activity is concentration dependent. All three pharmacodynamic Indices (area under the concentration curve (AUC)/MBC, peak concentration (Cmax)/MBC, and time above MBC (T > MBC)) correlated with bacterial killing; however, AUC/MBC correlated best (r = 0.71). In a second experiment we found comparable bacterial killing with multiple doses of trovafloxacin given either every serum half-life or every two serum half-lives. In both experiments bacterial regrowth occurred when the concentration of trovafloxacin in CSF fell below the MBC. These data have been used in formulating an appropriate regimen for trovafloxacin treatment of bacterial meningitis in children.

Pharmacodynamics of vancomycin for the treatment of experimental penicillin- and cephalosporin-resistant pneumococcal meningitis

With the emergence of beta-lactam antibiotic resistance among strains of Streptococcus pneumoniae, vancomycin has assumed an important role in the treatment of bacterial meningitis. Using the rabbit meningitis model, we evaluated the pharmacokinetics and pharmacodynamics of vancomycin in this setting. Animals were given 80 mg/kg of body weight daily in two or four divided doses to determine the penetration and activity of vancomycin in cerebrospinal fluid (CSF); each regimen was administered with and without dexamethasone. Mean peak (2 h) concentrations in CSF that were four- to eightfold higher than the minimum bactericidal concentration (MBC; 0.5 microgram/ml) for the pathogen were adequate for bacterial clearance. In both groups concentrations in CSF remained higher than the MBC for greater than 80% of the respective dosing intervals, and the penetration of vancomycin into CSF was 20%. Mean concentrations in CSF at 24 to 36 h of therapy were lower than those achieved during the first 12 h, consistent with a decline in the level of antibiotic entry into CSF as inflammation wanes. Rates of bacterial clearance were similar for the two regimens, and for all animals cultures of CSF were sterile by 36 h. The coadministration of dexamethasone significantly reduced the penetration of vancomycin into CSF by 29% and significantly lowered the rate of bacterial clearance during the first 6 h in animals receiving 20-mg/kg doses of vancomycin. For animals receiving 40-mg/kg doses, therapeutic peak concentrations in CSF were obtained even with steroid use, suggesting that the effect of steroids may be circumvented by the use of larger daily doses of vancomycin.

Mycoplasma pneumoniae pneumonia in a mouse model

To investigate the pathogenesis of acute Mycoplasma pneumoniae infection, BALB/c mice were anesthetized with metofane, and M. pneumoniae was introduced intranasally on days 0, 1, and 2. Mice were sacrificed on days 0-15. A histopathologic scoring system defined inflammatory changes in the lungs on a scale of 0-26 (least to most severe). Broth cultures were positive for all nasal passage and bronchoalveolar lavage (BAL) specimens. Histopathologic scores ranged from 0 to 21. The mean log10 (cfu/mL) were 4.1-6.4 on days 1-10 and >/=1.7 on days 13-15 for nasal passage and BAL specimens. Serum polymerase chain reaction was negative. ELISA for serum IgM and immunoblots for M. pneumoniae antibody were positive in 21 (62%) of 34 and 33 (97%) of 34 infected animals, respectively, at days 8-15. ELISA for IgG antibody was negative. This mouse pneumonia model can be used to study the immunologic and therapeutic responses to acute M. pneumoniae infection.

Medical care for mass gatherings at collegiate football games

BACKGROUND

Many articles have reviewed medical care at mass gatherings, but few have specifically looked at care provided during football games. Some of the largest gatherings occur at various stadiums during football season.

METHODS

We analyzed the medical care provided for the spectators at Williams-Brice Stadium for the University of South Carolina 1995 football season. The average attendance per game was 69,427; seven home games were played. Six physician/nurse/paramedic/paramedic teams provided medical care using prehospital equipment.

RESULTS

Medical care was given to 526 individuals, an average of 1.08 +/- 0.37 per 1,000 spectators per game. Records of 465 persons (88%) were available for review. The most common complaints were headache (48%), trauma (16%), gastrointestinal distress (10%), and environmental (7%). Nineteen patients (4%) required transport to nearby hospitals for further evaluation.

CONCLUSIONS

These results reflect patients with medical complaints seen during one collegiate football season in South Carolina. We believe this information can be used in planning medical care needs at other mass gatherings.

Clindamycin therapy of experimental meningitis caused by penicillin- and cephalosporin-resistant Streptococcus pneumoniae

Although penicillin resistance among Streptococcus pneumoniae strains is increasing in many areas, resistance to clindamycin remains low. In our well-characterized rabbit meningitis model, we conducted experiments to evaluate the bacteriologic efficacy of clindamycin after a penicillin- and cephalosporin-resistant S. pneumoniae strain was intracisternally inoculated. Animals received a loading intravenous dose of 30 mg of clindamycin per kg of body weight and then two doses of 20 mg/kg given 5 h apart. In addition to clindamycin, some animals received dexamethasone (DXM) with or without ceftriaxone. The concentrations of clindamycin in cerebrospinal fluid were from 8.9 to 12.8% of the concomitant concentrations in serum and were unaffected by DXM administration. Mean changes in CFU (log10 per milliliter) at 10 and 24 h were -3.7 and -6.1, respectively, for clindamycin-treated rabbits, -3.6 and -6.3 for clindamycin-DXM-treated rabbits, -3.9 and -5.8, respectively, for clindamycin-ceftriaxone-treated rabbits, and -5.0 and -6.7, respectively, for clindamycin-ceftriaxone-DXM-treated rabbits. By 24 h all but one of the cultures of cerebrospinal fluid (that from a clindamycin-DXM-treated rabbit) were sterile. Because of the potential risk for clindamycin-treated rabbits to develop macrolide-lincosamide resistance, we attempted, unsuccessfully, to induce clindamycin resistance in vitro in two S. pneumoniae strains. Although clindamycin therapy might be effective in selected patients with multiple-drug-resistant pneumococcal meningitis who have failed conventional treatments, clinical experience is necessary before it can be recommended.

Mouse liver microsomal metabolism of chloral hydrate, trichloroacetic acid, and trichloroethanol leading to induction of lipid peroxidation via a free radical mechanism

Metabolism of chloral hydrate (CH) by male B6C3F1 mouse liver microsomes (control-microsomes) generated free radical intermediates that resulted in endogenous lipid peroxidation, forming malondialdehyde (MDA), formaldehyde (FA), acetaldehyde (ACT), acetone, and propionaldehyde. Because MDA, FA, and ACT are tumorigens, endogenous formation of lipid peroxidation products via a free radical mechanism may be responsible for hepatocellular tumorigenicity of CH to the B6C3F1 mice. Trichloroacetic acid (TCA) and trichloroethanol (TCE), the primary metabolites of CH, also generated free radicals and induced lipid peroxidation. Lipid peroxidation from TCA equaled that induced by CH, whereas that from TCE was 3- to 4-fold lower, suggesting that metabolism of CH to TCA may be the predominant pathway leading to lipid peroxidation. Metabolism of CH, TCA, and TCE by liver microsomes of mice pretreated with pyrazole (pyrazole-microsomes) yielded lipid peroxidation products at a level 2- to 3-fold higher than those from liver microsomes of untreated mice. In addition, CH-induced lipid peroxidation catalyzed by control-microsomes and pyrazole-microsomes was reduced significantly by 2,4-dichloro-6-phenylphenoxyethylamine, a general cytochrome P450 inhibitor. Thus, our study suggests that cytochrome P450 is the enzyme catalyzing the metabolic activation of CH and its metabolites (TCA and TCE) leading to lipid peroxidation, and that CYP2E1 may be the major isozyme responsible. This latter conclusion was supported by results using human lymphoblastoid cells expressing cytochrome P4502E1, which metabolized CH to reactants inducing mutations, whereas the parental cell line was inactive.

The limited role of pneumolysin in the pathogenesis of pneumococcal meningitis

The aim of this study was to determine the role of pneumolysin, an intracellular toxin of Streptococcus pneumoniae, in the pathogenesis of pneumococcal meningitis. Recombinant pneumolysin (1 microgram), when injected intracisternally into rabbits, resulted in a brisk inflammatory response. However, a pneumolysin-deficient strain of S. pneumoniae caused meningeal inflammation in rabbits indistinguishable from that induced by the parent pneumolysin-producing strain. Furthermore, similar enhancement of meningeal inflammation occurred after ampicillin therapy in animals infected with either the parent strain or the pneumolysin-deficient mutant. These results suggest that although pneumolysin can stimulate the inflammatory cascade in the central nervous system, it is not necessary for the pathogenesis of meningeal inflammation nor does it play a role in postantibiotic enhancement of meningeal inflammation.

Tibial fractures--a useful plastering technique

The management of the acute tibial fracture is controversial, since no single method is appropriate in all circumstances and treatment indications often overlap. Given the potential problems in the management of this often difficult fracture, it is important that the attending clinician be familiar with both operative and conservative methods of treatment. In recent years, operative intervention has become increasingly popular, particularly the use of the intra-medullary locking nail, but such techniques are not without complications, including delayed union, non-union, malunion and infection. The authors strongly believe that conservative treatment remains an important option in the treatment armamentarium. A plastering technique is therefore described which is easy to perform, maintains good reduction and avoids the need for skilled assistance, excessive analgesia or an anaesthetic. It can be performed when the patient is initially assessed in the accident department, and it has a definitive role in the treatment of closed tibial fractures.

Evaluation of CP-99,219, a new fluoroquinolone, for treatment of experimental penicillin- and cephalosporin-resistant pneumococcal meningitis

CP-99,219 is a new fluoroquinolone that has excellent activity against gram-positive organisms including penicillin- and cephalosporin-resistant Streptococcus pneumoniae strains. In our well-established rabbit model of meningitis, we conducted experiments to determine the concentrations of CP-99,219 in cerebrospinal fluid (CSF) after intravenous administration and its ability to eradicate two penicillin-resistant pneumococcal isolates. The peak and trough concentrations of CP-99,219 in the CSF were from 19 to 25% of the concentrations simultaneously obtained in serum and were unaffected by concomitant dexamethasone administration. Compared with untreated (control) animals, three doses of CP-99,219 given 5 h apart significantly reduced the bacterial count in CSF by 5 to 6 log10 CFU at 10 h. Although 47% of the dexamethasone-treated animals and 18% of those not given the steroid had positive cultures at 24 h (14 h after administration of the last antibiotic dose), the mean bacterial counts did not change from those observed at 10 h. Additionally, only results for animals infected with one of the two pneumococcal strains appeared to be affected by concomitant dexamethasone therapy.

Neurotoxicity of glucocorticoids in the primate brain

Severe and prolonged physical and psychological stress is known to cause brain damage; long-term torture victims in prison have later developed psychiatric disorders and cerebral cortical atrophy observed in CT scans (Jensen, Genefke, Hyldebrandt, Pedersen, Petersen, and Weile, 1982). In nonhuman primates, we observed degeneration and depletion of the hippocampal neurons in African green monkeys that had been severely abused by cagemates and died with complications of multiple gastric ulcers and adrenal cortical hyperplasia (Uno, Tarara, Else, Suleman and Sapolsky, 1989). In our previous studies the administration of dexamethasone (DEX) (5 mg/kg) to pregnant rhesus monkeys at 132 to 133 days of gestation induced degeneration and depletion of the hippocampal pyramidal and dentate granular neurons in the brains of 135-gestation-day fetuses, and these changes were retained in the brains of fetuses at near term, 165 days of gestation (Uno, Lohmiller, Thieme, Kemnitz, Engle, Roecker, and Farrell, 1990). We also found that implantation of a cortisol pellet in the vicinity of the hippocampus in adult vervet monkeys induced degeneration of the CA3 pyramidal neurons and their dendritic branches (Sapolsky, Uno, Rebert, and Finch, 1990). Thus, hippocampal pyramidal neurons containing a high concentration of glucocorticoid receptors appear to be highly vulnerable to either hypercortisolemia caused by severe stress or to exposure to exogenous glucocorticoids. To study the long-term postnatal sequelae of prenatal brain damage, eight rhesus monkeys were treated with either DEX (5 mg/kg), 5 animals, or vehicle, 3 animals, at 132 to 133 days of gestation. After natural birth, all animals lived with their mothers for 1 year. At 9 months of age, we found that DEX-treated animals had significantly high plasma cortisol at both base and post-stress (isolation) levels compared to age-matched vehicle-treated animals. Magnetic resonance images (MRI) of the brain at 20 months of age showed an approximately 30% reduction in size and segmental volumes of the hippocampus in DEX-treated compared to vehicle-treated animals. Measurements of whole brain volume by MRI showed no significant differences between DEX and vehicle groups. Prenatal administration of a potent glucocorticoid (DEX) induced an irreversible deficiency of the hippocampal neurons and high plasma cortisol at the circadian baseline and post-stress levels in juvenile rhesus monkeys. These results suggest that the hippocampus mediates negative feedback of cortisol release; a lack or deficiency of the hippocampal neurons attenuates this feedback resulting in hypercortisolemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Time-kill studies of antibiotic combinations against penicillin-resistant and -susceptible Streptococcus pneumoniae

Time-kill studies were conducted to evaluate antibiotic combinations against four strains of Streptococcus pneumoniae for which the MICs of penicillin were 0.03, 0.25, 1 and 4 mg/L, respectively. After 8 h of antibiotic exposure the combination of ceftriaxone and vancomycin showed enhanced activity against all four strains. Penicillin plus vancomycin and ceftriaxone plus gentamicin showed enhanced activity against the three penicillin-resistant strains. Combinations of vancomycin and rifampicin were indifferent. These results are similar to those found previously in the rabbit meningitis model suggesting that time-kill studies over 8 h may be useful in predicting in-vivo antibiotic interactions in resistant pneumococcal infections.

Effect of dexamethasone on therapy of experimental penicillin- and cephalosporin-resistant pneumococcal meningitis

Treatment of pneumococcal meningitis has become problematic because of the emergence of penicillin- and cephalosporin-resistant strains and because of the concern that dexamethasone therapy might reduce penetration of antibiotics into the cerebrospinal fluid (CSF). We addressed these issues with our rabbit meningitis model by studying two pneumococcal isolates that were resistant to penicillin and ceftriaxone and susceptible to vancomycin and rifampin. Ceftriaxone, vancomycin, and rifampin were given alone or in combination, with or without coadministration of dexamethasone. Treatment was started 12 to 14 h after intracisternal inoculation of approximately 10(4) CFU of one of the organisms. Rifampin concentrations in serum and CSF were similar, regardless of whether dexamethasone was given, whereas those of ceftriaxone were somewhat lower at each time point in animals given dexamethasone. The penetration of vancomycin into CSF was consistently and substantially reduced with dexamethasone treatment, which resulted in a delay in CSF sterilization not observed in non-dexamethasone-treated animals. When rifampin was used with ceftriaxone for treatment of meningitis caused by the more resistant strain, bacteriologic cure occurred promptly, with or without dexamethasone therapy. In areas with high rates of occurrence of resistant pneumococcal strains, we believe initial empiric therapy of bacterial meningitis should include two antibiotics: ceftriaxone and either rifampin or vancomycin. When dexamethasone is used, the combination of ceftriaxone and rifampin is preferred for therapy.

Screening for cephalosporin-resistant Streptococcus pneumoniae with the Kirby-Bauer disk susceptibility test

Kirby-Bauer disk susceptibility tests with five standard cephalosporin disks were performed on 23 penicillin-resistant Streptococcus pneumoniae isolates for which ceftriaxone MICs were 0.125 to 4 micrograms/ml. Cefuroxime disk inhibition zone diameters distinguished clearly isolates for which ceftriaxone MICs were > or = 2 micrograms/ml from more susceptible strains, whereas cephalothin, ceftizoxime, cefotaxime, and ceftriaxone disks distinguished these isolates less clearly than the cefuroxime disk did.

Dilemmas in diagnosis and management of cephalosporin-resistant Streptococcus pneumoniae meningitis

We recently managed an infant with meningitis caused by Streptococcus pneumoniae in whom ceftriaxone failed to sterilize the cerebrospinal fluid after 6 days of therapy. This strain, which had a penicillin minimal inhibitory concentration (MIC) of 2 micrograms/ml, appeared susceptible to ceftriaxone (MIC < 0.5 micrograms/ml) when evaluated by a commercial MIC panel (Microtech Medical Systems, Inc., Aurora, CO) but was found to have a ceftriaxone MIC of 4 micrograms/ml when evaluated by conventional microtiter broth dilution technique. Furthermore ceftriaxone therapy of meningitis induced with this strain in a rabbit model was ineffective. Thirteen of 112 pneumococcal strains (11.6%) isolated recently at Children's Medical Center of Dallas were penicillin-resistant, and 3 of these were highly penicillin-resistant (MIC > or = 2 micrograms/ml). The incidence of pneumococcal strains with cefotaxime MICs > or = 1.0 micrograms/ml has increased from 0 of 258 from 1981 to 1983 to 5 of 112 (4.5%) from 1991 to 1992. The definition of cephalosporin resistance for pneumococci requires modification and further studies of the antibiotic management of meningitis caused by such strains are needed because resistance to cephalosporins is increasing and the extended spectrum cephalosporins may be ineffective as sole therapy.

Visualization of dopamine nerve terminals by positron tomography using [18F]fluoro-beta-fluoromethylene-m-tyrosine

[18F]-6-Fluoro-beta-fluoromethylene-m-tyrosine ([18F]FFMMT) was evaluated as a potential imaging agent for dopamine nerve terminals using positron emission tomography (PET). Biodistribution and time course of this tracer in mice after i.p. injection was consistent with the distribution of dopamine. PET imaging studies involving rhesus macaques showed specific uptake in the dopamine-rich caudate-putamen region. This specific localization was blocked by inhibiting the enzyme L-aromatic amino acid decarboxylase and the transport of the tracer into brain was shown to be stereospecific. These results show the promise of L-[18F]FFMMT as a PET tracer in monitoring degeneration of the CNS dopamine system.

Comparative evaluation of loracarbef and amoxicillin-clavulanate for acute otitis media

One hundred five infants and children with acute otitis media were randomized to therapy with loracarbef, an experimental carbacephem antibiotic, or amoxicillin-clavulanate (Augmentin), an approved drug for this disease. Ninety-two were evaluable (46 in each group). Middle ear fluid samples obtained for culture before therapy grew Haemophilus spp. in 30% of cases, pneumococci in 29% of cases, and Moraxella catarrhalis in 15% of cases. beta-Lactamase-producing bacteria were found in 37% of patients. Clinical failure occurred in four loracarbef-treated patients and one amoxicillin-clavulanate-treated patient (P = 0.361). Recurrence of acute otitis media was more common in the 2 to 3 weeks after loracarbef treatment (eight patients) than it was after amoxicillin-clavulanate therapy (three patients), but not significantly so (P = 0.197). Thus, combined failure and recurrence occurred in 12 loracarbef-treated patients and four amoxicillin-clavulanate-treated patients (P = 0.052). Gastrointestinal side effects occurred in 13 loracarbef-treated and 21 amoxicillin-clavulanate-treated patients (P = 0.13). Diaper rash was more common with amoxicillin-clavulanate (22 patients) than with loracarbef (10 patients; P = 0.016). Satisfactory results were achieved with both antibiotics, and adverse effects, although common, were minor.

Pharmacokinetics of cefprozil in infants and children

Twenty pediatric patients (ages, between 8 months and 8 years) received a single oral dose of cefprozil at levels of 15 and 30 mg/kg of body weight. Cefprozil consists of cis (BMY-28100) and trans (BMY-28167) isomers in an approximately 90:10 ratio. Six plasma samples were collected from each pediatric patient and assayed for drug concentrations. As measured by a microbiological assay, peak concentrations of 11.16 and 15.93 micrograms of cefprozil per ml occurred at 1 h for patients who received the 15- and 30-mg/kg doses, respectively. The respective mean half-lives of cefprozil were 1.77 and 2.14 h, and the respective mean areas under the curve were 28.05 and 45.28 micrograms.h/ml for patients who received the 15- and 30-mg/kg doses. When measured by a high-pressure liquid chromatography method, peak concentrations of 12.09 and 18.04 micrograms of the cis isomer per ml were obtained at 1 h, with mean half-lives of 1.63 and 2.06 h and mean areas under the curve of 30.48 and 49.34 micrograms.h/ml in patients who received the 15- and 30-mg/kg doses, respectively. For the trans isomer, peak concentrations of 1.16 and 1.63 micrograms/ml occurred at 1 h, respectively, with mean half-lives of 1.61 and 1.65 h and mean areas under the curve of 2.89 and 4.34 micrograms.h/ml in patients who received the 15- and 30-mg/kg doses, respectively.

Loracarbef concentrations in middle ear fluid

Loracarbef concentrations in plasma and middle ear fluid (MEF) were measured in specimens obtained approximately 2 h after doses of 7.5 or 15 mg/kg. The mean +/- standard deviation concentrations in MEF were 2.0 +/- 2.6 mg/liter (48% of the concentration in plasma) after the smaller dose and 3.9 +/- 2.6 mg/liter (42% of the concentration in plasma) after the larger dose. With the larger dose, the concentrations in MEF were greater than the MIC for 90% of strains of the usual pathogens of acute otitis media tested in 16 of 17 specimens.

Simultaneous detection of Escherichia coli heat-stable and heat-labile enterotoxin genes with a single RNA probe

A single RNA probe was synthesized and used to detect simultaneously the methanol-soluble heat-stable enterotoxin and heat-labile enterotoxin genes in Escherichia coli strains. The results with the biotinylated or radioactive probe correlated 100% with the biological assay results for both toxins. The RNA probe detected the three known heat-stable enterotoxin A alleles.

Pharmacokinetics of LY163892 in infants and children

Two dosages (7.5 and 15 mg/kg of body weight) of LY163892 were given to infants and children, and five plasma specimens were collected for antibiotic assay during the ensuing 4 h. Peak concentrations of 12.6 and 18.7 micrograms/ml occurred at 45 min. The mean half-lives were 0.85 and 0.78 h, and the mean areas under the curve were 24.4 and 38.0 micrograms.h/ml.

In vitro susceptibilities of common pediatric pathogens to LY163892

LY163892 is a carbacephem antibiotic for oral administration with an antibacterial spectrum similar to that of cefaclor and amoxicillin-clavulanic acid. It has greater stability than cefaclor and greater activity against beta-lactamase-producing Haemophilus influenzae and Escherichia coli. LY163892 is less active than amoxicillin against streptococci and less active than amoxicillin-clavulanic acid against Branhamella catarrhalis but comparable against other pathogens.

Five vs. ten days of therapy for acute otitis media

In a double blind study 175 patients with acute otitis media were randomized into 2 treatment groups: 10 days of therapy with cefaclor or 5 days of therapy followed by 5 days of placebo. The dosage of cefaclor was 40 mg/kg/day administered orally in equally divided doses at 12-hour intervals. Tympanocentesis before treatment yielded specimens that contained Streptococcus pneumoniae or Haemophilus influenzae or both in 55% of specimens. Branhamella catarrhalis was isolated from 21% of specimens. Culture of material from the ear canal of patients with spontaneous perforation of the tympanic membrane of less than 24 hours duration yielded pneumococci or H. influenzae or both in 38% of specimens and staphylococci in 31%. Patients were scheduled for follow-up examinations at 5 or 6, 10, 30, 60 and 90 days. Of the 175 children 151 were evaluable at 10 days. There were 123 patients with both tympanic membranes intact at the time of diagnosis. There were 6 (10%) treatment failures of therapy in the 59 patients assigned to 5 days of therapy and 4 (6%) failures and 1 (2%) early relapse in the 64 assigned to 10 days of therapy (difference not significant). There were 28 evaluable patients with spontaneous perforation. There were 8 (53%) failures in the 15 children assigned to 5 days of therapy and only 1 (8%) failure in the 13 children assigned to receive 10 days of therapy (P = 0.016, Fisher exact test). Rates of reinfection and persistent middle ear effusion at 10, 30, 60 and 90 days follow-up were not significant different in patients assigned to 5 to 10 days of therapy. In patients with acute otitis media with intact tympanic membranes we have not been able to show any advantage of the standard duration of 10 days of therapy over a shortened course of 5 days. A 5-day course of antibiotic therapy does not appear to be sufficient for children with acute otitis media and spontaneous purulent drainage.

Function of the adrenal cortex in patients with major depression

Failure to suppress cortisol secretion after administration of dexamethasone occurs in up to 50% of depressed patients. To test whether this hypothalamic-pituitary-adrenal (HPA) overactivity is associated with adrenocortical hyperresponsiveness, we performed dexamethasone suppression tests (DSTs) and adrenocorticotropic hormone (ACTH) stimulation tests in depressed subjects and subjects with other psychiatric disorders. Three groups were defined: depressed nonsuppressors, depressed suppressors, and other suppressors. While predexamethasone and postdexamethasone cortisol concentrations were greater in the depressed nonsuppressor group, ACTH concentrations did not differ among groups. After receiving alpha-ACTH[1-24] (4.2 micrograms/kg), depressed nonsuppressors had greater increases in stimulated cortisol secretion than the other groups. These results demonstrate that in a subgroup of depressed patients, HPA overactivity is associated with adrenocortical hyperresponsiveness.

Imipenem and cilastatin in acute osteomyelitis and suppurative arthritis. Therapy in infants and children

Twenty-five infants and children with acute osteomyelitis (n = 7), suppurative arthritis (n = 11), or both (n = 7) were treated with imipenem and cilastatin sodium. Patients ranged in age from 5 months to 11.3 years. Needle aspiration of infected sites was performed in all patients, and 11 (44%) required further surgical drainage. Imipenem and cilastatin sodium in a dosage of 100 mg/kg/d was used for children 3 years of age or younger, while older ones received 60 mg/kg/d intravenously, divided in four equal doses. Bacterial pathogens were identified in 15 patients (60%): Staphylococcus aureus in five, Haemophilus influenzae b in four, Pseudomonas aeruginosa in two, Streptococcus pneumoniae in one, group A Streptococcus in one, Kingella kingae in one, and Citrobacter amalonaticus in one. All isolates were susceptible to imipenem in vitro. Imipenem and cilastatin therapy was continued for a median of six days followed by treatment with appropriate orally administered antibiotics. Median peak serum bactericidal titers after imipenem and cilastatin infusions were 1:512 for S aureus, 1:32 for H influenzae b, 1:512 for streptococci, and 1:16 for gram-negative rods. All but one patient with P aeruginosa osteomyelitis responded favorably to imipenem and cilastatin. The median duration until resolution of symptoms was six days. Imipenem and cilastatin infusions were well tolerated, and side effects included maculopapular rash in one patient, watery diarrhea in one, and mild transient elevation of alanine aminotransferase levels in three. Because of imipenem and cilastatin's unusually broad spectrum of activity and its relative safety, this drug combination can be used for the initial, empiric therapy of acute bone and joint infections in pediatric patients.

Comparison of piperacillin vs. ticarcillin plus tobramycin in the treatment of acute pulmonary exacerbations of cystic fibrosis

During a 22-month period 35 children with cystic fibrosis received 52 courses of antibiotic therapy for acute pulmonary exacerbations, including 26 cases of therapy with piperacillin and 26 courses with ticarcillin plus tobramycin. Groups were similar in age (5 vs. 5.4 years), disease severity based on Schwachman scores and presenting symptoms. Pseudomonas aeruginosa was the most common organism isolated in 90% of sputum cultures. Mean minimal inhibitory concentrations for piperacillin, ticarcillin and tobramycin were 8, 64 and 1 microgram/ml, respectively. Piperacillin pharmacokinetic data revealed an average half-life in serum of 36 minutes. Peak serum concentrations averaged 144 micrograms/ml, and after 4 hours serum concentrations continued to exceed the P. aeruginosa 90% minimal inhibitory concentration in 50% of children. The dosage requirement for tobramycin was quite variable, necessitated monitoring of aminoglycoside serum concentrations and in most cases resulted in at least one dosage adjustment. Emergence of resistant bacteria was not seen in 26 courses of piperacillin therapy. Both regimens were effective and well-tolerated. Single agent therapy has the advantage of providing reliable serum concentrations and, in contrast to the standard therapy, does not necessitate monitoring of serum drug concentrations.

Comparative treatment trial of augmentin versus cefaclor for acute otitis media with effusion

A total of 150 children with acute otitis media were randomly allocated to treatment with amoxicillin-potassium clavulanate (Augmentin) or with cefaclor. Each drug was given in a daily dosage of approximately 40 mg/kg in three divided doses for ten days. Tympanocentesis done before treatment yielded specimens that contained pneumococcus or Haemophilus sp or both in 67% of specimens. Viridans group streptococci were isolated from 10% of specimens and Branhamella catarrhalis from 6%. Patients were scheduled for follow-up examinations at midtreatment, end of therapy, and at 30, 60, and 90 days. Of the 150 children, 130 were evaluable. Five of 60 patients (8%) treated with cefaclor were considered therapeutic failures because of persistent purulent drainage and isolation of the original pathogen or suprainfection. There were no failures among patients treated with Augmentin (P = .019). Rates of relapse, recurrent acute otitis media with effusion, and persistent middle ear effusion were comparable in the two groups of patients. Diaper rash, or loose stools, or both were significantly more common in children treated with Augmentin (34%) than in those taking cefaclor (12%), but in no case was it necessary to discontinue medication because of these mild side effects (P = .002). Cefaclor therapy was discontinued in one patient because of severe abdominal pain and vomiting. In this study, treatment with Augmentin was superior to treatment with cefaclor in the acute phase of acute otitis media with effusion, but Augmentin produced more adverse effects. The rates of persistent middle ear effusion and recurrent acute otitis media with effusion were comparable with the two regimens.

Pharmacokinetics and bacteriological efficacies of apalcillin and cefpiramide in experimental pneumococcal meningitis

Rabbits with experimentally induced pneumococcal meningitis were given single 25-mg/kg doses of apalcillin or cefpiramide. Mean percentages of the drug concentration in cerebrospinal fluid versus that in blood serum were 7.6% with apalcillin and 3.9% with cefpiramide. Bactericidal activity in cerebrospinal fluid resulted in mean reductions of from 4 to 5 log10 CFU/ml, and cerebrospinal fluid cultures became sterile for four of six animals treated with each drug.

Detection of teichoic acid antibodies in children with staphylococcal infections

The presence of serum antibodies to teichoic acid was evaluated by gel diffusion and enzyme-linked immunosorbent assay in 14 patients with deep-seated staphylococcal infection, in 5 patients with superficial staphylococcal infections, in 10 patients with Gram-positive infections other than staphylococcal and in 12 age-matched, uninfected patients. Serum samples were obtained on admission and serially each week during hospitalization. Teichoic acid antibodies were detected by gel diffusion in only 5 of 14 patients with deep-seated staphylococcal infections, in 1 of 10 patients with other Gram-positive infections and in none of the other patients. With the enzyme-linked immunosorbent assay method all patients with deep-seated staphylococcal infections had concentrations of teichoic acid antibodies of 1:1600 or greater, and these titers were significantly larger than those in the other groups of patients. Using a titer of 1:3200 or greater as a diagnostic level in children with deep-seated Staphylococcus aureus infections, the sensitivity was 93% and the specificity was 89%. For all staphylococcal infections the sensitivity was 79% and the specificity was 96%.

Relatively penicillin-resistant pneumococcal infections in pediatric patients

Two hundred fifty-eight isolates of Streptococcus pneumoniae obtained from 232 infants and children at Children's Medical Center, Dallas, from November 1, 1981, to March 31, 1983, were screened for susceptibility to penicillin. On 1-microgram oxacillin disks 21 strains (8%) had zones of inhibition of 17 mm or less, and the tube-dilution minimal inhibitory concentrations of penicillin were from 0.125 to 0.5 micrograms/ml. These strains were designated as relatively resistant S. pneumoniae (RRSP). Prior therapy with a beta-lactam agent had occurred in 56% of patients with RRSP disease compared with 14% of randomly selected children with infections due to susceptible strains of S. pneumoniae (P = 0.009). Fifteen children (6%) had diseases due to RRSP ranging from sepsis or meningitis to otitis media or conjunctivitis. Four children, including the two patients with meningitis, had unsatisfactory responses to therapy with a beta-lactam antibiotic. Vancomycin or chloramphenicol is preferred for therapy of disease due to RRSP.

Randomized trial of cefamandole plus amdinocillin versus cefamandole in serious pediatric infections

In a randomized, prospective clinical trial cefamandole therapy was compared with cefamandole plus amdinocillin in infants and children with suspected bacterial infections. Fifty-two infections in 50 patients with bone and joint (19 infections), pulmonary (19 infections), soft tissue (eight infections), and urinary tract (6 infections) diseases were treated. Bacterial infection was documented in 31 patients. All isolates were susceptible to cefamandole except one strain of Serratia marcescens, which was susceptible to the combination. In vitro synergy was demonstrated in all coliform bacilli, in three of seven Haemophilus strains, and in six of 16 gram-positive cocci. No correlation between degree of serum bactericidal activity and presence or absence of synergy could be demonstrated. One patient treated with cefamandole died; all other patients responded promptly to therapy without serious adverse drug effects.

Ceftriaxone versus ampicillin and chloramphenicol for treatment of bacterial meningitis in children

78 patients with bacterial meningitis were evaluated in a prospective, randomised study comparing twice-daily ceftriaxone as single-drug therapy with ampicillin and chloramphenicol given every 6 h. The groups were comparable in age, sex, days of illness before admission, and bacterial colony counts in cerebrospinal fluid (CSF). The pathogens were Haemophilus influenzae type b (54 cases), streptococci (9 cases), meningococci (9 cases), and unknown (6 cases). In 40 CSF specimens obtained 4-12 h after initiation of therapy, cultures were negative in 57% of the ceftriaxone patients and in 42% of the others. The mean falls in the CSF bacterial colony counts were 4.7 and 5.0 log10 colony-forming units/ml, respectively. Mean bactericidal activity in CSF was significantly greater in the ceftriaxone than in the conventional treatment group at the beginning and end of therapy. There were no significant differences in clinical responses or in frequency of complications, except for mild diarrhoea, which occurred in 16 ceftriaxone patients and in 8 in the other group (p less than 0.05).

Pharmacokinetics of cefuroxime in infants and children with bacterial meningitis

A total of 38 patients with bacterial meningitis received either 50 or 75 mg of cefuroxime per kg of body weight given as a 15-min intravenous infusion during the first to third days of therapy. The mean peak plasma concentrations of cefuroxime after doses of 50 and 75 mg/kg were 105 and 152 micrograms/ml, respectively. In five patients, pharmacokinetic values were determined after multiple doses of 50 mg of cefuroxime per kg every 6 h. The mean peak plasma concentrations were 120 micrograms/ml after the first dose and 130 micrograms/ml after the last dose. The concentrations at 6 h were 3.25 and 11.0 micrograms/ml after the first and last doses, respectively. The elimination half-life was approximately 1.5 h, and the apparent volume of distribution was 650 ml/kg. The plasma clearance rate was 195 to 198 ml/min per 1.73 m2. Penetration into the cerebrospinal fluid, expressed as the ratio of the cerebrospinal fluid to serum areas under the curve times 100, was 6.4% in patients given 50 mg of cefuroxime per kg and 10% in those who received 75 mg/kg. The cerebrospinal bactericidal activity in 27 patients was less than or equal to 1:8; only 2 patients had bactericidal activity of less than or equal to 1:2.