Exosomes in immunoregulation of chronic lung diseases

Exosomes are nano-sized, membrane-bound vesicles released from cells that transport cargo including DNA, RNA, and proteins, between cells as a form of intercellular communication. In addition to their role in intercellular communication, exosomes are beginning to be appreciated as agents of immunoregulation that can modulate antigen presentation, immune activation, suppression, and surveillance. This article summarizes how these multifaceted functions of exosomes may promote development and/or progression of chronic inflammatory lung diseases including asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis. The potential of exosomes as a novel therapeutic is also discussed.

Reappraisal of the historical selective pressures for the CCR5-Delta32 mutation

HIV strains are unable to enter macrophages that carry the CCR5-Delta32 deletion; the average frequency of this allele is 10% in European populations. A mathematical model based on the changing demography of Europe from 1000 to 1800 AD demonstrates how plague epidemics, 1347 to 1670, could have provided the selection pressure that raised the frequency of the mutation to the level seen today. It is suggested that the original single mutation appeared over 2500 years ago and that persistent epidemics of a haemorrhagic fever that struck at the early classical civilisations served to force up the frequency to about 5x10(-5) at the time of the Black Death in 1347.

Human population dynamics

Time-series analysis of parish register series can be used to study human population dynamics at three different levels: (i) The metapopulation of preindustrial rural England. A short wavelength, exogenous oscillation in the burials series of 404 parishes can be detected which, it is suggested, was driven by a cycle of malnutrition associated with wheat prices. (ii) Individual populations, where long-term endogenous oscillations in baptisms and burials of wavelength 30-32 years or 43-44 years can be detected. Their characteristics and causes are explored and elucidated by matrix modelling. (iii) The separate neonatal, post-neonatal, child and adult mortalities in an individual population each show an exogenous short wavelength oscillation and a model is presented to show how these cycles were driven by an oscillation in grain prices and how they interacted. Together, they formed the feedback in a saturated, density-dependent population which was fundamental in controlling the characteristics of the longer wavelength endogenous oscillations in the population dynamics described above.

Modelling the dynamics of scarlet fever epidemics in the 19th century

Annual deaths from scarlet fever in Liverpool, UK during 1848-1900 have been used as a model system for studying the historical dynamics of the epidemics. Mathematical models are developed which include the growth of the population and the death rate from scarlet fever. Time-series analysis of the results shows that there were two distinct phases to the disease (i) 1848-1880: regular epidemics (wavelength = 3.7 years) consistent with the system being driven by an oscillation in the transmission coefficient (deltabeta) at its resonant frequency, probably associated with dry conditions in winter (ii) 1880-1900: an undriven SEIR system with a falling endemic level and decaying epidemics. This period was associated with improved nutritive levels. There is also evidence from time-series analysis that raised wheat prices in pregnancy caused increased susceptibility in the subsequent children. The pattern of epidemics and the demographic characteristics of the population can be replicated in the modelling which provides insights into the detailed epidemiology of scarlet fever in this community in the 19th century.

Tumor-targeted IL-2 amplifies T cell-mediated immune response induced by gene therapy with single-chain IL-12

Induction, maintenance, and amplification of tumor-protective immunity after cytokine gene therapy is essential for the clinical success of immunotherapeutic approaches. We investigated whether this could be achieved by single-chain IL-12 (scIL-12) gene therapy followed by tumor-targeted IL-2 using a fusion protein containing a tumor-specific recombinant anti-ganglioside GD(2) antibody and IL-2 (ch14.18-IL-2) in a poorly immunogenic murine neuroblastoma model. Herein, we demonstrate the absence of liver and bone marrow metastases after a lethal challenge with NXS2 wild-type cells only in mice (five of six animals) vaccinated with scIL-12-producing NXS2 cells and given a booster injection of low-dose ch14.18-IL-2 fusion protein. This tumor-protective immunity was effective 3 months after initial vaccination, in contrast to control animals treated with a nonspecific fusion protein or an equivalent mixture of antibody and IL-2. Only vaccinated mice receiving the tumor-specific ch14.18-IL-2 fusion protein revealed a reactivation of CD8(+) T cells and subsequent MHC class I-restricted tumor target cell lysis in vitro. The sequential increase in the usage of TCR chains Vbeta11 and -13 in mouse CD8(+) T cells after vaccination and amplification with ch14.18-IL-2 suggests that the initial polyclonal CD8(+) T cell response is effectively boosted by targeted IL-2. In conclusion, we demonstrate that a successful boost of a partially protective memory T cell immune response that is induced by scIL-12 gene therapy could be generated by tumor-specific targeting of IL-2 with a ch14.18-IL-2 fusion protein. This approach could increase success rates of clinical cancer vaccine trials.

Clonal characteristics of T cell infiltrates in skin and synovium of patients with psoriatic arthritis

Psoriasis is a chronic inflammatory skin disease that is often complicated by an inflammatory arthritis. Considerable evidence implicates cellular immune responses in psoriatic skin lesions, but the pathogenesis of the associated arthritis has not been elucidated. We analyzed T cell antigen receptor beta chain variable (TCRbetaV) gene repertoires among peripheral blood lymphocytes, skin and synovium of nine patients with psoriatic arthritis. RNase protection assays were used to quantitate the expression levels of 25 TCRbetaV genes, and CDR3 region sequencing was used to further characterize selected expansions. All patients exhibited significant TCRbetaV biases in the peripheral blood and moreover, all had expansions common to both skin and synovium. CDR3 sequencing demonstrated these expansions frequently consisted of oligo- or monoclonal populations. Although no ubiquitous CDR3 nucleotide sequences were identified, two patients shared identical sequences and several highly homologous amino acid motifs were present in skin and synovium among and between individual patients. Findings of common TCRbetaV expansions in diverse inflammatory sites, among multiple afflicted individuals, suggest that these T cell proliferations are driven by engagements with a limited set of conventional antigens. These findings demonstrate an important role for cognate T cell responses in the pathogenesis of psoriatic arthritis, and further suggest the inciting antigen(s) is identical or homologous between afflicted skin and synovium.

The effects of population density and malnutrition on the dynamics of whooping cough

Liverpool, a seaport in NW England, suffered severely from lethal infectious diseases in the second half of the 19th century: the population was densely crowded and malnourished and life expectancy was low. Time-series analysis shows that the epidemics of whooping cough (i) had an interepidemic interval of 2.9 years, 1863-85, which lengthened to 3.4 years, 1885-1900 (ii) were strongly coherent with wheat prices (P < 0.001) and (iii) also correlated with cycles of seasonal weather conditions. It is suggested from mathematical modelling that the epidemics in this compromised population were maintained (i.e. the system was driven) by an oscillation of malnutrition and by seasonal weather conditions. A model that incorporates both the dynamics of whooping cough and the demographic characteristics of the population is presented. It has been shown to replicate the dynamics of the epidemics and has been used to predict the changes with time of (i) the force of the infection and (ii) the proportion of those infected with whooping cough who died.

The interacting effects of prices and weather on population cycles in a preindustrial community

The exogenous cycles and population dynamics of the community at Penrith, Cumbria, England, have been studied (1557-1812) using aggregative analysis, family reconstitution and time series analysis. This community was living under marginal conditions for the first 200 years and the evidence presented is of a homeostatic regime where famine, malnutrition and epidemic disease acted to regulate the balance between resources and population size. This provides an ideal historic population for an investigation of the direct and indirect effects of malnutrition. Throughout the period studied, a short wavelength oscillation in grain prices was apparently the major external factor that drove exogenous cycles in mortality, birth rate, and migration. In particular, the different responses of children to variations in food supply are emphasised; fluctuations in poor nutrition correlated significantly with the variations in mortality rates for infants (probably indirectly during pregnancy and directly during the first year of life) and for young children (via susceptibility to lethal infectious diseases). Migratory movements contributed to the maintenance of homeostasis in the population dynamics. A medium wavelength cycle in low winter temperatures was associated with a rise in adult mortality which, in turn, promoted an influx of migrants into this saturated habitat. A model incorporating these interacting associations between vital events and exogenous cycles is presented: grain prices were an important density-dependent factor and constituted the major component of the negative feedback of this population and drove the exogenous, short wavelength mortality cycles. Cycles of births and immigration provide a positive feedback for the build-up of susceptibles and the initiation of smallpox epidemics and increased population size.

Dexamethasone inhibits lung epithelial cell apoptosis induced by IFN-gamma and Fas

Lung epithelium plays a central role in modulation of the inflammatory response and in lung repair. Airway epithelial cells are targets in asthma, viral infection, acute lung injury, and fibrotic lung disease. Activated T lymphocytes release cytokines such as interferon-gamma (IFN-gamma) that can cooperate with apoptotic signaling pathways such as the Fas-APO-1 pathway to induce apoptosis of damaged epithelial cells. We report that IFN-gamma alone and in combination with activation of the Fas pathway induced apoptosis in A549 lung epithelial cells. Interestingly, the corticosteroid dexamethasone was the most potent inhibitor of IFN-gamma- and IFN-gamma plus anti-Fas-induced apoptosis. IFN-gamma induced expression of an effector of apoptosis, the cysteine protease interleukin-1 beta-converting enzyme, in A549 cells. Dexamethasone, in contrast, induced expression of an inhibitor of apoptosis, human inhibitor of apoptosis (hIAP-1), also known as cIAP2. We suggest that the inhibition of epithelial cell apoptosis by corticosteroids may be one mechanism by which they suppress the inflammatory response.

The dynamics of measles epidemics

The interepidemic interval (T) of measles in London from 1647 to 1837 evolved progressively from 5-yearly to 2-yearly by 1800. Measles mortality was significantly ( p<0.001) cross-correlated with the annual wheat prices, a good index of nutrition although at a 2-year lag. Epidemics correlated with low autumn temperatures (p<0. 001). A linearised model of the dynamics of epidemics shows that T is determined by the product of population (N) and susceptibility (beta) and that the system will settle at its steady state unless the epidemics are driven. It is suggested that (i) the progressive change in T was caused by a rise in population size (N) and an increased susceptibility (beta) related to malnutrition and (ii) epidemics were driven by oscillations in low autumn temperature (p<0. 001) and by cycles of susceptible young children produced by malnutrition during pregnancy.

Autoimmunity caused by disruption of central T cell tolerance. A murine model of drug-induced lupus

A side effect of therapy with procainamide and numerous other medications is a lupus-like syndrome characterized by autoantibodies directed against denatured DNA and the (H2A-H2B)-DNA subunit of chromatin. We tested the possibility that an effect of lupus-inducing drugs on central T cell tolerance underlies these phenomena. Two intrathymic injections of procainamide-hydroxylamine (PAHA), a reactive metabolite of procainamide, resulted in prompt production of IgM antidenatured DNA antibodies in C57BL/6xDBA/2 F1 mice. Subsequently, IgG antichromatin antibodies began to appear in the serum 3 wk after the second injection and were sustained for several months. Specificity, inhibition and blocking studies demonstrated that the PAHA-induced antibodies showed remarkable specificity to the (H2A-H2B)-DNA complex. No evidence for polyclonal B cell activation could be detected based on enumeration of Ig-secreting B cells and serum Ig levels, suggesting that a clonally restricted autoimmune response was induced by intrathymic PAHA. The IgG isotype of the antichromatin antibodies indicated involvement of T cell help, and proliferative responses of splenocytes to oligonucleosomes increased up to 100-fold. As little as 5 microM PAHA led to a 10-fold T cell proliferative response to chromatin in short term organ culture of neonatal thymi. We suggest that PAHA interferes with self-tolerance mechanisms accompanying T cell maturation in the thymus, resulting in the emergence of chromatin-reactive T cells followed by humoral autoimmunity.

T-cell receptor biases and clonal proliferations in blood and pleural effusions of patients with lung cancer

We sought evidence that pulmonary carcinomas mediate a cellular immunologic response by analyzing T-cell antigen receptor beta-chain variable gene (TCRBV) repertoires of lymphocytes from peripheral blood (PBL) and malignant pleural effusions (PEL) of five lung cancer patients. Expression levels of 27 TCRBV were quantitated by multiprobe RNase protection assay (RPA), and clonal expansions were identified by sequence enrichment nuclease assay (SENA) and junctional region sequencing. Abnormal TCRBV expansions were identified in all subjects by RPA (mean 6.9 +/- 1.7/patient), and their number closely correlated with elapsed time since initial diagnosis (r = 0.97). SENA, performed in specimens from three patients, confirmed the presence of mono or oligoclonality in 48% of abnormal RPA expansions, and further identified T-cell clones among TCRBV with normal expression levels. The majority of clonal expansions were among PEL, and were nearly equally divided between CD4 and CD8. These data show that T-cell repertoires of lung cancer patients are characterized by marked abnormalities and frequent clonal expansions, most likely representing responses to unique, tumor-specific antigens (TSA). Moreover, this process appears exaggerated among PEL, further suggesting that malignant effusions include local proliferations of tumor reactive T cells. These findings imply the presence of lung cancer TSA capable of eliciting cellular immune responses and raise the possibility that selective immunotherapies can ultimately be developed.

T cell receptor (TCR) BV gene repertoires and clonal expansions of CD4 cells in patients with HIV infections

Despite extensive investigation, the pathogenesis of T cell depletions that characterize AIDS has not been elucidated. To study this process further, we evaluated T cell antigen receptor beta-chain variable gene (TCRBV) repertoires in peripheral blood lymphocytes (PBL) of 23 HIV-infected patients. Expression levels of 28 TCRBV were determined by multiprobe RNase protection assay after polymerase chain reaction (PCR) amplifications. Abnormal expansions (> 2 s.d. from mean normal values) were frequent in HIV CD4, accounting for 26% of total measured TCRBV in this population. The number and magnitude of abnormalities among individuals were inversely proportional to their CD4 counts (P < 0.012 and P < 0.01, respectively). While abnormalities were not randomly distributed among TCRBV subfamilies, no particular genes were expanded or contracted among all patients. Only 14% of CD8 TCRBV were proportionally expanded (P < 0.01 compared with CD4), and there were limited concordances between paired CD8 and CD4 repertoires among individuals. CDR3 length analyses and TCRBV sequencing showed that most CD4 expansions comprised clonal or oligoclonal populations. Thus, T cell responses in HIV patients are characterized by severe TCRBV biases and clonal expansions among CD4 subsets, and these processes are exaggerated with disease progression. The heterogeneity and oligoclonality of the TCRBV expansions are consistent with responses to HIV-encoded or other conventional antigens rather than superantigenic effects. The presence of CD4 clonal proliferations in these patients may be important in the pathogenesis of HIV, and the absence or reduction of many T cell specificities due to oligoclonal expansions may increase susceptibility to opportunistic infections.

Oscillatory dynamics of smallpox and the impact of vaccination

The evolution of smallpox epidemics in London, 1647-1893, was studied by time series analysis of deaths from the disease in the Bills of Mortality. The interepidemic interval (T) evolved progressively from 4 years to 2 years at 1800. The dynamics of epidemics during 1647-1800 are explicable in terms of the transmission of viral diseases which shows that (i) T is determined by the product of population size (N) and susceptibility (beta), (ii) T determines the mean age of catching the disease, (iii) the system will settle at its steady-state, endemic level unless the epidemics are driven. It is suggested that (i) the progressive change in T was initially caused by a rise in N and later by an increased beta related to malnutrition and (ii) the epidemics were driven by an oscillation in delta beta associated with seasonal dry conditions. The effects of variolation and vaccination became apparent after 1800: the endemic level fell progressively, the epidemics were reduced in amplitude and they were not driven. The dynamics of the disease can now be described by an SEIR model: severe outbreaks of smallpox are followed by decaying epidemics. Endemic smallpox mortality also interacts with the dynamics of the population so that a long wavelength oscillation (associated with recovery after the plague) and a 5/6 year (associated with immigration) oscillation are generated.

The dynamics of scarlet fever epidemics in England and Wales in the 19th century

There was a marked rise in scarlet fever mortality in England and Wales in the mid-nineteenth century and spectral analysis of the registration details, 1847-80, shows that the interepidemic interval was 5-6 years, but after 1880 the endemic level fell and the fatal epidemics disappeared. The dynamics of the scarlet fever epidemics can be represented by a linearized mathematical model and because the system is lightly damped, it could be driven by an oscillation in susceptibility. Epidemics were significantly correlated with dry conditions in spring/summer (P < 0.001), suggesting that these produced a low amplitude oscillation in susceptibility which drove the system. Epidemics also correlated (P < 0.001) with an oscillation in wheat prices but at a lag of 3 years, suggesting that malnutrition during pregnancy caused increased susceptibility in the subsequent children which interacted synergistically with seasonal dry conditions. Scarlet fever mortality was sharply reduced after 1880 in parallel with falling wheat prices suggesting that the remarkable period of high scarlet fever mortality (1840-80) was dependent on poor nutritive levels during that time.

Pulmonary capillaritis and alveolar hemorrhage. Update on diagnosis and management

Pulmonary vascular inflammatory disorders may involve all components of the pulmonary vasculature, including capillaries. The principal histopathologic features of pulmonary capillaritis include capillary wall necrosis with infiltration by neutrophils, interstitial erythrocytes, and/or hemosiderin, and interalveolar septal capillary occlusion by fibrin thrombi. Immune complex deposition is variably present. Patients often present clinically with diffuse alveolar hemorrhage, which is characterized by dyspnea and hemoptysis; diffuse, bilateral, alveolar infiltrates on chest radiograph; and anemia. Pulmonary capillaritis has been reported with variable frequency and severity as a manifestation of Wegener's granulomatosis, microscopic polyarteritis, systemic lupus erythematosus, Goodpasture's syndrome, idiopathic pulmonary renal syndrome, Behçet's syndrome, Henoch-Schönlein purpura, IgA nephropathy, antiphospholipid syndrome, progressive systemic sclerosis, and diphenylhydantoin use. In addition to history, physical examination, and routine laboratory studies, certain ancillary laboratory tests, such as antineutrophil cytoplasmic antibodies, antinuclear antibodies, and antiglomerular basement membrane antibodies, may help diagnose an underlying disease. Diagnosis of pulmonary capillaritis can be made by fiberoptic bronchoscopy with transbronchial biopsy, but thoracoscopic biopsy is often employed. Since many disorders can result in pulmonary capillaritis with diffuse alveolar hemorrhage, it is crucial for clinicians and pathologists to work together when attempting to identify an underlying disease. Therapy depends on the disorder that gave rise to the pulmonary capillaritis and usually includes corticosteroids and cyclophosphamide or azathioprine. Since most diseases that result in pulmonary capillaritis are treated with immunosuppression, infection must be excluded aggressively.

T cell receptor biases and clonal proliferations among lung transplant recipients with obliterative bronchiolitis

Obliterative bronchiolitis (OB) is the most serious late complication of lung transplantation, but the pathogenesis of this disorder has not been elucidated. We sought evidence that OB is mediated by a cellular immunologic response by characterizing T cell antigen receptor beta-chain variable gene (TCRBV) repertoires in lung allograft recipients. Expression levels of 27 TCRBV among recipients were determined by multiprobe RNase protection assay after PCR amplification. In comparison to recipients with no evidence of rejection (n = 9), the PBL TCRBV repertoires of OB subjects (n = 16) exhibited more frequent expansions (16 vs. 9% of all measured TCRBV, P < 0.02), and the magnitudes of these abnormalities were greater (8.2 +/- 0.8 vs. 4.5 +/- 0.3 SD from mean normal values, P < 0.01). TCRBV sequencing showed these expansions were composed of clonal or oligoclonal populations. Thus, T cell responses in the recipients are marked by highly selective clonal expansions, presumably driven by indirect recognition of a limited number of immunodominant alloantigens. These processes are exaggerated among allograft recipients with OB, implying that cognate immune mechanisms are important in the pathogenesis of the disorder. Furthermore, the prominence of finite, distinct TCR phenotypes raise possibilities for development of novel diagnostic modalities and targeted immunotherapies for OB and other manifestations of chronic allograft rejection.

Intrathymic injection of polynucleosomes delays autoantibody production in BXSB mice

T-cell dependent autoimmunization with nucleosomes appears to be an early event in the induction of lupus anti-chromatin antibodies. We investigated this phenomenon by injecting H1-stripped chromatin polynucleosomes into the thymuses of BXSB male lupus-prone mice. In comparison to uninjected controls, the production of IgG antichromatin, anti-native DNA, and anti-denatured DNA were significantly reduced among the injected animals for a period of 8 to 10 weeks. Peripheral T-cells from intrathymic (i.t.)-treated animals showed decreased proliferative responses to polynucleosomes compared to those from uninjected controls. Treatment did not affect T-cell antigen receptor V beta profiles, excluding the possibility that results were due to superantigen-imposed deletions. In situ staining using the TUNEL method demonstrated that generation and phagocytosis of apoptotic material in thymuses of unmanipulated BXSB mice were similar to normal controls. These findings show that polynucleosomes likely comprise the antigens for helper T-cell engagement and induction of lupus-associated anti-chromatin antibodies. Bypassing the underlying defect of T-cell tolerance for polynucleosomal antigens among BXSB mice, by i.t. administration of exogenous polynucleosomes, results in abrogation of autoantibody production.

Whooping cough epidemics in London, 1701-1812: infection dynamics, seasonal forcing and the effects of malnutrition

Time series analysis of the London Bills of Mortality, 1701-1812, reveals that whooping cough appeared as a lethal endemic disease after 1700 with epidemics of progressively increasing amplitude after 1720. The interepidemic period changed from 5 years (1720-1750) to 3 years (1750-1785) before returning to 5 years during 1785-1812. The epidemiology of whooping cough can be described by the mathematics of linearized dynamic systems and the interepidemic interval is determined by population size and susceptibility. The latter was governed by fluctuating levels of malnutrition, which were directly associated with oscillations in the wheat prices. It is suggested that the epidemics were driven in 1720-1785 by fluctuating seasonal temperatures which interacted with oscillations in wheat prices to produce an oscillation in susceptibility, but after 1785 the dynamics escaped from the pattern predicted by mathematical theory and the epidemics were apparently driven only by the wheat prices which generated a regular oscillation in susceptibility. The results emphasize the importance of an adequate nutritive level in combating whooping cough in the Third World today where it remains a lethal disease in children because of immunodeficiency linked to fluctuating and severe malnutrition which is often a consequence of crop cycles.

Aerosolized cyclosporine in lung recipients with refractory chronic rejection

This study evaluated aerosolized cyclosporine as rescue therapy for lung transplant recipients with unremitting chronic rejection. Nine patients with histologic active obliterative bronchiolitis and progressively worsening airway obstruction refractory to conventional immune suppression received aerosolized cyclosporine. Improvement in rejection histology was seen in seven of nine patients. We compared the changes in the FVC and FEV1 over time using linear regression analysis in these seven histologic responders and nine historical control patients. During the pretreatment period for both the experimental and control groups, the FVC and FEV1 declined at comparable rates. After aerosolized cyclosporine there was stabilization of pulmonary function, whereas in the controls there was continued decline. Cyclosporine blood levels were less than 50 ng/ml 24 h after an aerosolized dose of 300 mg in five patients receiving oral tacrolimus. Nephrotoxicity, hepatotoxicity, and a greater than expected rate of infection was not observed. This study suggests that aerosolized cyclosporine is safe and may be effective therapy for refractory chronic rejection in lung transplant recipients.

The plague in Penrith, Cumbria, 1597/8: its causes, biology and consequences

Using a family reconstitution study the biology of the plague in Penrith, Cumbria in 1597/8 is described in detail; it was an explosive epidemic that spread rapidly within families and 606 individuals died of the plague, some 40% of the population. The age-specific mortality corresponded with the calculated age structure of the population and infection appeared to be random. The sex ratio of victims was 1.37 females to 1 male. The plague spread from the northeast via Richmond and then exploded in the Eden valley, appearing almost simultaneously in Penrith, Kendal and Carlisle. The details of the epidemics and the location and the climate of these widely separated small market towns show that bubonic plague was not the causative agent, and the possibility that anthrax was responsible for the drastic mortality is briefly considered. The population rapidly built up after the plague, largely by immigration and not by increased fertility, and steady-state conditions were re-established within 5 years and continued for 150 years. This severe mortality crisis of the plague had a profound effect on the population at Penrith, triggering long wavelength oscillations in both baptisms and burials in this population living under marginal conditions and maintained in steady-state by density-dependent factors.

Infant mortality and famine: a study in historical epidemiology in northern England

OBJECTIVE

To examine whether periodic variations in annual infant mortality were associated with malnutrition and the poor quality of the food supply available to the community.

DESIGN

Retrospective study of historical epidemiology of infant mortality by time series analysis and family reconstitution of parish registers of burials and baptisms.

SETTING

Penrith, Cumbria, England, 1557-1812.

SUBJECTS

A total of 17,500 births during 1557-1812.

RESULTS

This community in the Eden Valley, Cumbria, close to the Scottish borders, was living under marginal conditions with high mortality and low fertility. Clear oscillations in infant mortality synchronise with the oscillations in the wheat price index which is regarded as a measure of the availability of food to the community, and to pregnant and nursing mothers in particular. Input-output analysis showed that the relationship between the wheat price index (input) and infant mortality (output) was highly significant (p < 0.001). Events during the famine of 1623 have been analysed in detail: high wheat prices during pregnancy caused subsequent severe infant mortality but did not have indirect effects on the subsequent mortality of the surviving children over the age of 1 year. Non-stationary oscillations in neonatal and post neonatal mortality were strongly coherent (p < 0.001) with the wheat price index throughout the period.

CONCLUSIONS

Infant mortality is particularly sensitive to famine and also to the quality of the food supply available to pregnant and nursing mothers. The lags between neonatal and post-neonatal mortalities and wheat prices, together with the analysis of the famine of 1623, support the hypothesis that neonatal mortality was related to malnutrition in pregnancy whereas post-neonatal mortality was primarily directly dependent on exogenous causes in the first year of life.

Delivery and distribution of aerosolized cyclosporine in lung allograft recipients

The aim of the present study was to identify factors determining the delivery to and distribution of aerosolized cyclosporine A (CSA) in the lungs of patients with severe pulmonary allograft rejection. Five such patients inhaled a previously characterized radioaerosol consisting of 4 to 6 cc of CSA (50 mg/ml) in ethanol mixed with technetium-99m (99mTc) bound to human serum albumin, generated by an AeroTech II nebulizer. The total dose of CSA depositing in the lungs was determined with a previously described inspiratory/expiratory mass-balance filter technique. Regional distribution of drug within the lungs was measured using a gamma camera. In addition, the following physiologic parameters were measured: regional volume and ventilation using xenon-133 (133Xe) equilibrium and 133Xe washout, respectively, and regional perfusion using intravenous 99mTc macroaggregates. The relationships between these parameters and regional drug deposition were assessed using linear regression analysis. The lung dose ranged from 20 to 53 mg (0.097 to 0.175 mg CSA deposited per milligram placed in nebulizer). In recipients of single-lung allografts, preferential drug deposition occurred either in the allograft (two patients) or in the native lung (one patient). Marked nonuniformities in regional distribution were also apparent in two double-lung allograft recipients. There was a weak but statistically significant correlation between regional drug deposition and regional ventilation, as measured by 133Xe washout (r = -0.542, p = 0.014), suggesting that although regional ventilation is important, it is not the only factor determining regional deposition in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Modelling the different smallpox epidemics in England

Time series analysis has revealed two different patterns of smallpox epidemics in Britain in the seventeenth and eighteenth centuries: in large conurbations (exemplified by London) the disease was endemic whereas medium-sized rural towns (exemplified by Penrith, Cumbria) suffered from 5 year epidemics with no cases of smallpox in the inter-epidemic years. The oscillations (epidemics) persisted for over 150 years and it is suggested that both systems were pumped up by regular fluctuations in susceptibility (delta beta). Modelling suggests that: (i) the natural frequency of oscillations in large cities is two years and the system is pumped up by a 1 year, seasonal input; (ii) it takes five years to build up a pool of susceptibles in medium-sized towns by new births and epidemics are then triggered by a 5 year input. The equations represent a system that has two components, a basic linear element with the remainder of the system being nonlinear; modelling a progressive increase in delta beta in London illustrates theoretically how a predominantly linear response changes to a nonlinear response and ultimately to chaos. A variation in susceptibility is a theoretical condition for inducing chaos; the undriven system cannot become chaotic. Modelling populations of progressively increasing size/density and applying a 1 year or 5 year sinusoidal oscillation in delta beta illustrates the fundamental distinction in the response of medium-sized rural towns and large cities.

A comparison of ganciclovir and acyclovir to prevent cytomegalovirus after lung transplantation

In an attempt to modify the sequelae of cytomegalovirus (CMV) infections after lung transplantation, 25 allograft recipients were randomized to either ganciclovir 5 mg/kg once a day 5 d/wk (Group G) or acyclovir 800 mg four times a day (Group A). All subjects received ganciclovir during postoperative Weeks 1 through 3, and they were then given either A or G regimens until Day 90. At termination of study enrollment, the cumulative incidence of all CMV infections (including seroconversions) was increased in Group A compared with that in Group G (75% versus 15%, p < 0.01), as was the incidence of overt CMV shedding and/or pneumonitis (50% versus 15%, p < 0.043). In comparison with those in Group G, subjects in Group A were also afflicted with an increased prevalence of obliterative bronchiolitis (OB) during the first year after transplantation (54% versus 17%, p < 0.033). Intravenous catheters for ganciclovir administration resulted in four complications among three of the subjects in Group G (23%). The short-term benefits of ganciclovir were ultimately limited, moreover, in that cumulative rates of CMV and prevalence of OB are now similar in both treatment groups after approximately 2 yr of observation. We conclude that prolonged ganciclovir prophylaxis decreases the early incidence of CMV and OB among lung transplant recipients, but these effects are of finite duration. Although CMV prevention appears to have considerable potential value in this population, definitive viral prophylaxis will require development of protracted or repeated treatment regimens, or longer-acting agents.

Recurrence of sarcoidosis in pulmonary allograft recipients

Lung transplantation is a potentially curative therapy for the end-stage pulmonary sequelae of sarcoidosis. We reviewed the course of five lung allograft recipients with underlying sarcoidosis (S) at the University of Pittsburgh Medical Center and compared them with a control group (C) of 44 contemporaneous transplant recipients with other respiratory diseases. Sarcoid granulomata have developed in the allografts of 4 S, although these lesions have not yet been demonstrated to result in clinically significant abnormalities. In comparison with C, sarcoidosis patients had significantly greater mean grades of acute rejection during the first 3 months after transplantation (2.1 +/- 0.3 versus 1.6 +/- 0.1, S and C, respectively, p < 0.042) and larger proportions of lung biopsies showing more than mild acute rejection (40 versus 18%, p < 0.012) and lymphocytic bronchitis (30 versus 13%, p = 0.02), as well as a greater percentage of polymorphonuclear leukocytes in BAL returns (34.9 +/- 5.4 versus 19.0 +/- 1.6, p < 0.01). The two groups did not differ, however, in frequency of obliterative bronchiolitis, survival, or pulmonary function. We conclude that lung transplant recipients with underlying sarcoidosis are very likely to develop recurrent disease in the allograft and have more severe acute rejection responses, especially in the first weeks after transplantation. Pulmonary transplantation appears to be an efficacious therapy for end-stage sarcoidosis, but the long-term sequelae of the increased acute rejection and recurrent sarcoidosis in the allograft remain to be determined.

The dynamics of smallpox epidemics in Britain, 1550–1800

Time-series analysis, a valuable tool in studying population dynamics, has been used to determine the periodicity of smallpox epidemics during the seventeenth and eighteenth centuries in two contrasting representative situations: 1) London, a large city where smallpox was endemic, and 2) Penrith, a small rural town. The interepidemic period was found to be two years in London and five years in Penrith. Equations governing the dynamics of epidemics predict 1) a two-year periodicity and 2) that oscillatory epidemics die out quickly. It is suggested that epidemics were maintained by a periodic variation in susceptibility linked either to a five-year cycle of malnutrition or to an annual cycle. Computer modeling shows how the very different patterns of epidemics are related to population size and to the magnitude of the oscillation in susceptibility.

The dynamics of smallpox epidemics in Britain, 1550-1800

Time-series analysis, a valuable tool in studying population dynamics, has been used to determine the periodicity of smallpox epidemics during the seventeenth and eighteenth centuries in two contrasting representative situations: 1) London, a large city where smallpox was endemic, and 2) Penrith, a small rural town. The interepidemic period was found to be two years in London and five years in Penrith. Equations governing the dynamics of epidemics predict 1) a two-year periodicity and 2) that oscillatory epidemics die out quickly. It is suggested that epidemics were maintained by a periodic variation in susceptibility linked either to a five-year cycle of malnutrition or to an annual cycle. Computer modeling shows how the very different patterns of epidemics are related to population size and to the magnitude of the oscillation in susceptibility.

An hypothesis for the periodicity of smallpox epidemics as revealed by time series analysis

Parish registers have been studied by time series analysis to detect smallpox epidemics in England during 1600-1800. Confirmatory evidence was provided by the seasonality of child mortality. A 5-year cycle in smallpox epidemics was detected in medium-sized, rural towns. Consideration of the mathematics of the dynamics of viral diseases suggests that the true interepidemic period where smallpox is endemic should be 2-3 years and it is concluded that, in the towns studied, the disease was not endemic but that the oscillations were established by 5-year cycles of periods of famine associated with high wheat prices. The cross-correlation function between the two cycles shows zero lag and the input-output function shows significant coherence. Another epidemic follows only when a sufficient density of susceptibles has been established by births, so that the cycles become phase-locked. It is predicted that smallpox (i) was endemic in London and other large cities, with 2-3 year epidemics, (ii) was epidemic with a 5-year oscillation in rural towns, (iii) did not reach epidemic proportions in scattered communities.

Sequelae of cytomegalovirus pulmonary infections in lung allograft recipients

Indirect effects of cytomegalovirus (CMV) infections in lung transplant recipients (LTX) have not previously been described in detail. We compared spirometric results, development of chronic rejection, rates of respiratory superinfections, and mortality as long as 2 yr after transplantation, between 62 LTX who never developed CMV (CMV-) and 56 LTX with a history of CMV pulmonary infections (CMV+). Initial spirometric parameters were near identical for both groups, but determinations > or = 6 months after transplantation showed that expiratory flows of the CMV+ were significantly reduced. Actuarial prevalences of chronic allograft rejection (CR) at 2 yr were highest among CMV+ with biopsy-proved pneumonitis (74%) compared with 22% among CMV- (p < 0.038). Bacterial or fungal pneumonias developed in 58.9% of the CMV+, whereas the rate among CMV- was 38.7% (p < 0.05). Only 36% of LTX with CMV pneumonitis lived 2 yr compared with 70% survival for CMV- (p < 0.016). Ganciclovir treatment of CMV infections decreased rates of respiratory superinfections and improved survival of patients, but it did not appear to affect subsequent development of CR. We conclude that CMV pulmonary infections among LTX result in serious late sequelae and that current treatment is ineffectual for prevention of viral-associated CR in these patients.

Morphine and hydromorphone epidural analgesia. A prospective, randomized comparison

Because evidence from uncontrolled, unblinded studies suggested fewer side effects from epidural hydromorphone than from epidural morphine, we employed a randomized, blinded study design to compare the side effects of lumbar epidural morphine and hydromorphone in 55 adult, non-obstetric patients undergoing major surgical procedures. A bolus dose of epidural study drug was given at least 1 h prior to the conclusion of surgery, followed by a continuous infusion of the same drug for two postoperative days. Infusions were titrated to patient comfort. Visual analog scale (VAS) pain scores, VAS sedation scores, and subjective ratings of nausea and pruritus were assessed twice daily. The two treatments provided equivalent analgesia. Sedation scores and prevalence of nausea did not differ significantly between groups. Prevalence of pruritus, however, differed significantly on postoperative day 1, with moderate to severe pruritus reported by 44.4% of patients in the morphine group versus 11.5% in the hydromorphone group (P < .01). On post-operative day 2, reports of pruritus by patients receiving morphine remained higher than those among the hydromorphone-treated subjects, although this difference was no longer statistically significant (32% vs. 16.7%, P = .18). We conclude that lumbar epidural morphine and hydromorphone afford comparable analgesia, but the occurrence of moderate to severe pruritus on the first postoperative day is reduced by the use of hydromorphone.

Ganciclovir prophylaxis for cytomegalovirus infections in pulmonary allograft recipients

Cytomegalovirus (CMV) is a substantial cause of morbidity in pulmonary allograft recipients. In an attempt to decrease the prevalence of this infection, we treated 13 recipients at risk for cytomegalovirus with 3 wk of intravenous ganciclovir (5 mg/kg twice a day for 14 days, starting 5 days after the procedure, followed by 1 wk of the drug at a dose of 5 mg/kg/day). Following the ganciclovir course, patients received oral acyclovir, 800 mg three times a day for at least 2 months more. CMV infections developed in 5 recipients (38%), and none of these episodes occurred during the ganciclovir therapy. Neither of the 2 deaths in this group could be attributed to CMV. In comparison, the prevalence of CMV in the preceding cohort of 11 transplant recipients who were administered acyclovir alone was 91% (p << 0.01 by log-rank test), and there were 3 deaths due to viral infections (p = 0.08 by Fisher's exact test). Groups were similar in terms of immunosuppression and renal function during treatment, and none of the recipients developed leukopenia. We conclude that ganciclovir prophylaxis is well tolerated and appears to have considerable efficacy for prevention of CMV infections in pulmonary transplant recipients.

Interstitial and airspace granulation tissue reactions in lung transplant recipients

Twenty-three transbronchial and open-lung biopsies from patients who had received a lung allograft displayed fibromyxoid plugs of granulation tissue within airways, airspaces, and the interstitium in a patchy distribution. This granulation tissue-like reaction was identified in three clinicopathologic settings. First, 11 cases occurred with acute lung rejection, of which four cases had been partially treated with steroids for a previous rejection episode. Second, in seven cases the fibromyxoid tissue represented the healing phase of previously diagnosed diffuse alveolar damage resulting from preservation (harvest) injury to the allograft. Third, five cases were related to infection: herpes, Pseudomonas, Serratia, Staphylococcus, and Pneumocystis pneumonias. Although organizing pneumonia-like responses usually suggest an infectious episode, this reaction may be seen as a manifestation of acute lung rejection or ischemic lung injury.

Distinguishing between infection, rejection, and the adult respiratory distress syndrome after human lung transplantation

The adult respiratory distress syndrome, bacterial pneumonia, cytomegalovirus pneumonitis, acute rejection, or a combination thereof were the primary causes of radiographic infiltrates or gas exchange abnormalities that occurred early after lung transplantation. The time of occurrence after transplantation, standard measures of clinical assessment as for nontransplant patients (i.e., vital signs, weight, white blood cell count, sputum, and cultures, etc.), bronchoalveolar lavage, and transbronchial lung biopsy were the primary tools used to analyze these situations. Bacterial pneumonia always occurred after postoperative day 2, acute rejection after postoperative day 5, and cytomegalovirus pneumonitis after postoperative day 16. Although cultures of bronchoalveolar lavage fluid were useful to detect pneumonia caused by bacteria, virus, and fungus, the types of cells recovered by bronchoalveolar lavage were not diagnostic of any type of disorder. Transbronchial lung biopsy was necessary to detect acute rejection and cytomegalovirus pneumonitis. Thus the cause of an early radiographic infiltrate or impairment of gas exchange was almost always reliably determined by using standard tools of clinical assessment, knowledge of the usual temporal sequence of the complications, and judicious use of bronchoalveolar lavage and transbronchial lung biopsy.

Ventilatory effects of clonidine alone and in the presence of alfentanil, in human volunteers

Clonidine, an alpha 2-adrenergic agonist, can potentiate opioid-induced analgesia. In a double-blind placebo-controlled study in human volunteers, we sought to determine whether clonidine also potentiates opioid-induced respiratory depression. Hypercapnic ventilatory responses (minute ventilation, mean inspiratory flow rate, and mouth occlusion pressure) were measured in five healthy male volunteers on two separate occasions (with or without clonidine, approximately 3.5 micrograms.kg-1 orally) under the following conditions: baseline, 2 h after clonidine/placebo (alfentanil concentration of 0), and during computer-controlled alfentanil infusions to approximate plasma concentrations of 5, 10, 20, 40, and 80 ng.ml-1. Plasma alfentanil concentrations were measured before and after each rebreathing test, and clonidine concentrations were measured after each rebreathing test. The end-tidal CO2 (PET(CO2)) was measured continuously. Data were analyzed by repeated-measures analysis of variance. The PET(CO2) and measured concentrations of alfentanil were included as covariates, and a compound symmetry error analysis was assumed. Statistical significance was achieved when P less than 0.05. For minute ventilation, mean inspiratory flow rate, and mouth occlusion pressure there was a statistically significant relationship to the covariates of PET(CO2) and plasma alfentanil concentration. Clonidine, when compared to placebo, caused a small but significant depression of mean inspiratory flow rate. There was similarly a small, but statistically insignificant, depression of minute ventilation by clonidine. The mouth occlusion pressure was not affected by clonidine treatment. Clonidine treatment did not potentiate alfentanil-induced respiratory depression. Although the combination of an opioid and an alpha 2-adrenergic agonist may act synergistically for the analgesic response, there is no synergistic effect by this drug combination on respiratory depression.

Detection of inspiratory resistive loads by heart-lung transplant recipients

Human heart-lung transplantation recipients (HL) are models for the effects of selective lower respiratory tract denervation. We used a series resistor to examine thresholds of inspiratory flow resistance perception among 16 HL in comparison with 15 normal control subjects (C) and 12 heart transplant recipients (H). HL and C were closely age matched. H subjects were older and had mildly reduced lung volumes compared with the other groups. The perception threshold was defined as the added resistance (delta R) detected by subjects at 50% of random, blinded presentations. These delta R were subsequently expressed as a fraction of the airway resistance of the subject and baseline resistance of the apparatus (delta R/Raw + Rapparatus), otherwise known as the Weber fraction. The mean +/- SEM Weber fractions were nearly identical for HL and C (0.32 +/- 0.05 versus 0.34 +/- 0.05, respectively). The Weber fraction of H (0.74 +/- 0.17) was significantly greater than those of both other groups (p less than 0.05 by Kruskal-Wallis test). We conclude that lower respiratory tract afferents do not play a significant role in the perception of inspiratory resistive loads. The finding of an abnormally high Weber fraction in the heart transplant population remains unexplained but may be a function of age or restrictive pulmonary defects.

Donor cerebral emboli as a cause of acute graft dysfunction in lung transplantation

Early graft dysfunction in lung transplantation has many causes, most commonly preservation injury. This report details a more unusual cause of graft failure and respiratory decompensation in the early postoperative period donor cerebral emboli occluding segments of the pulmonary arterial tree in the implanted lung allografts of two patients who had received single lung implants from a common donor in whom massive cerebral trauma had been incurred in a motor vehicle accident. The incidence, complications, and clinical manifestations of cerebral emboli are discussed.

Naloxone reversal of hypotension due to captopril overdose

The hemodynamic effects of captopril and other angiotensin-converting enzyme inhibitors may be mediated by the endogenous opioid system. The opioid antagonist naloxone has been shown to block or reverse the hypotensive actions of captopril. We report a case of an intentional captopril overdose, manifested by marked hypotension, that resolved promptly with the administration of naloxone. To our knowledge, this is the first reported case of captopril-induced hypotension treated with naloxone. Our experience demonstrates a possible role of naloxone in the reversal of hypotension resulting from captopril.

Inspiratory timing of heart-lung transplant recipients during progressive hypercapnia

The relationship between tidal volume (VT) and inspiratory duration (TI) displays biphasic characteristics during progressive hypercapnia in humans: an initial phase in which VT increases while TI remains constant (region I) and a subsequent phase with reciprocal decreases of TI as VT continues to increase (region II). Region II behavior is generally attributed, albeit inferentially, to lung volume-mediated inflation inhibition (Breuer-Hering reflex). To investigate this phenomenon, we compared CO2 responses of 10 heart-lung transplant recipients (HL) with normal pulmonary function tests and 13 normal controls. Despite pulmonary denervation, the HL exhibited region II behavior identical to controls. In four additional HL with pulmonary restriction, there were comparative decreases of the region II slope (P less than 0.05), but the absolute VT where the phase change between regions occurred was indistinguishable from the other groups. We conclude that TI shortening in humans during progressive hypercapnia occurs in the absence of pulmonary reflexes. The consistency of the VT associated with phase changes, despite pulmonary denervation, suggests that the stimulus for this behavior is volume displacement of extra-pulmonary respiratory structures.

Hypercarbic ventilatory responses of human heart-lung transplant recipients

To evaluate the effects of chronic pulmonary denervation on ventilatory control, we compared the hypercarbic ventilatory responses (HCVR) of 12 human heart-lung transplant recipients (HL) and 24 normal control subjects (C). The six male HL were subsequently compared with eight male heart transplant recipients (H), as well as the 12 male C. All subjects had normal spirometry, but lung volumes of both transplant groups were somewhat less than those of C. The HCVR of HL and C were indistinguishable (2.68 +/- 0.28 versus 2.71 +/- 0.22 L/min/mm Hg, respectively). The increment of mouth occlusion pressure (delta Pm0.1/delta CO2), however, was markedly greater in HL (P much less than 0.01). The three male groups also had equivalent HCVR, and again, the HL had an increased delta Pm0.1/delta CO2. HL men exhibited larger increments of VT and decreased frequency responses during CO2 rebreathing than did male C and H, although these differences were statistically significant only in the comparison between the transplant groups. We conclude that HL with normal spirometry have appropriate HCVR, despite pulmonary denervation. Pm0.1 responses of these subjects are increased, however, reflecting either a compensatory response to greater respiratory impedances or an occult alteration of ventilatory mechanics. Moreover, compared with subjects with similar pulmonary function, e.g., heart transplant recipients, the breathing pattern of HL during progressive hypercarbia is consistent with the absence of vagal-mediated inflation inhibition.

Effects of pulmonary restriction on hypercapnic responses of heart-lung transplant recipients

Previous studies of hypercapnic ventilatory responses (HCVR) in human heart-lung transplant recipients (HLTX) have yielded conflicting results. We compared the HCVR of restricted transplant recipients (HLTX-R) to recipients with normal pulmonary function (HLTX-N), and normal controls (C). HLTX-R exhibited limited tidal volume responses, whereas their frequency responses were essentially identical to those of other subjects. Accordingly, HCVR of HLTX-R (1.45 +/- 0.59 l.min-1.Torr CO2(-1)) were significantly depressed compared with both HLTX-N and C (2.90 +/- 0.55 vs 3.05 +/- 1.23, respectively) (P less than 0.02). Despite undoubtedly greater ventilatory impedances, airway (mouth) occlusion pressure responses (Pm0.1) during hypercarbia of HLTX-R (0.46 +/- 0.28 cmH2O) were similar to those of C (0.43 +/- 0.20) and paradoxically blunted compared with HLTX-N (0.83 +/- 0.36) (P less than 0.02). We conclude that pulmonary reflexes are superfluous for maintenance of HCVR in HLTX with normal respiratory mechanics, whereas the presence of moderate restriction results in profound depression of CO2 responses among these subjects.