Prospective validity of a clinical prediction rule for response to non-surgical multidisciplinary management of knee osteoarthritis in tertiary care: a multisite prospective longitudinal study

OBJECTIVES

We tested a previously developed clinical prediction tool-a nomogram consisting of four patient measures (lower patient-expected benefit, lower patient-reported knee function, greater knee varus angle and severe medial knee radiological degeneration) that were related to poor response to non-surgical management of knee osteoarthritis. This study sought to prospectively evaluate the predictive validity of this nomogram to identify patients most likely to respond poorly to non-surgical management of knee osteoarthritis.

DESIGN

Multisite prospective longitudinal study.

SETTING

Advanced practice physiotherapist-led multidisciplinary service across six tertiary hospitals.

PARTICIPANTS

Participants with knee osteoarthritis deemed appropriate for trial of non-surgical management following an initial assessment from an advanced practice physiotherapist were eligible for inclusion.

INTERVENTIONS

Baseline clinical nomogram scores were collected before a trial of individualised non-surgical management commenced.

PRIMARY OUTCOME MEASURE

Clinical outcome (Global Rating of Change) was collected 6 months following commencement of non-surgical management and dichotomised to responder (a little better to a very great deal better) or poor responder (almost the same to a very great deal worse). Clinical nomogram accuracy was evaluated from receiver operating characteristics curve analysis and area under the curve, and sensitivity/specificity and positive/negative likelihood ratios were calculated.

RESULTS

A total of 242 participants enrolled. Follow-up scores were obtained from 210 participants (87% response rate). The clinical nomogram demonstrated an area under the curve of 0.70 (p<0.001), with greatest combined sensitivity 0.65 and specificity 0.64. The positive likelihood ratio was 1.81 (95% CI 1.32 to 2.36) and negative likelihood ratio 0.55 (95% CI 0.41 to 0.75).

CONCLUSIONS

The knee osteoarthritis clinical nomogram prediction tool may have capacity to identify patients at risk of poor response to non-surgical management. Further work is required to determine the implications for service delivery, feasibility and impact of implementing the nomogram in clinical practice.

Hip strength, quadriceps strength and dynamic balance are lower in people with unilateral knee osteoarthritis compared to their non-affected limb and asymptomatic controls

BACKGROUND

There is insufficient literature on multi-directional hip strength differences and dynamic balance between people with knee osteoarthritis (KOA) and healthy controls.

OBJECTIVE

In people with unilateral KOA, determine if hip/knee strength and dynamic balance differs (i) between sides, and (ii) compared to controls.

METHODS

Thirty-six participants (17 women; 65.5 ± 8.9 years) with unilateral KOA and 36 age- and sex-matched controls were included in a cross-sectional study. Outcomes included hip strength, quadriceps strength, and dynamic balance (three directions) during the Star Excursion Balance Test. Mixed ANOVA analysis was completed to investigate differences between Limbs and Groups. Mean differences (MD) and 95% confidence intervals (CI) were calculated.

RESULTS

Quadriceps and hip adduction strength were 16% (95%CI:10, 22) and 9% [95%CI: 3, 16) lower on the affected compared to non-affected side. Quadriceps and hip abduction, adduction, flexion, and extension strength (MD varying from 16%, 95%CI: 8, 25; to 34%, 95%CI: 17, 50) were weaker bilaterally in individuals with KOA compared to control. Posteromedial balance was 4% (95%CI: 2, 6) lower for affected compared to non-affected limbs in those with KOA and 13% (95%CI: 6, 21) lower in the affected limb compared to controls. Individuals with KOA had lower balance bilaterally in the anterior 11% (95%CI: 7, 15) and posterolateral 21% (95%CI: 13, 30) directions.

CONCLUSION

Hip/knee strength (especially in the sagittal and frontal planes) and dynamic balance are lower bilaterally in people with KOA compared to controls. Hip adduction strength is lower on the affected than non-affected limbs of people with KOA. Clinicians should consider that knee extension strength, hip strength, and dynamic balance are lower bilaterally in people with unilateral KOA.

Patient characteristics associated with a poor response to non-surgical multidisciplinary management of knee osteoarthritis: a multisite prospective longitudinal study in an advanced practice physiotherapist-led tertiary service

OBJECTIVES

To explore patient characteristics recorded at the initial consultation associated with a poor response to non-surgical multidisciplinary management of knee osteoarthritis (KOA) in tertiary care.

DESIGN

Prospective multisite longitudinal study.

SETTING

Advanced practice physiotherapist-led multidisciplinary orthopaedic service within eight tertiary hospitals.

PARTICIPANTS

238 patients with KOA.

PRIMARY AND SECONDARY OUTCOME MEASURES

Standardised measures were recorded in all patients prior to them receiving non-surgical multidisciplinary management in a tertiary hospital service across multiple sites. These measures were examined for their relationship with a poor response to management 6 months after the initial consultation using a 15-point Global Rating of Change measure (poor response (scores -7 to +1)/positive response (scores+2 to+7)). Generalised linear models with binomial family and logit link were used to examine which patient characteristics yielded the strongest relationship with a poor response to management as estimated by the OR (95% CI).

RESULTS

Overall, 114 out of 238 (47.9%) participants recorded a poor response. The odds of a poor response decreased with higher patient expectations of benefit (OR 0.74 (0.63 to 0.87) per 1/10 point score increase) and higher self-reported knee function (OR 0.67 (0.51 to 0.89) per 10/100 point score increase) (p<0.01). The odds of a poor response increased with a greater degree of varus frontal knee alignment (OR 1.35 (1.03 to 1.78) per 5° increase in varus angle) and a severe (compared with mild) radiological rating of medial compartment degenerative change (OR 3.11 (1.04 to 9.3)) (p<0.05).

CONCLUSIONS

These characteristics may need to be considered in patients presenting for non-surgical multidisciplinary management of KOA in tertiary care. Measurement of these patient characteristics may potentially better inform patient-centred management and flag the need for judicious monitoring of outcome for some patients to avoid unproductive care.

Impaired Epstein-Barr Virus-Specific Neutralizing Antibody Response during Acute Infectious Mononucleosis Is Coincident with Global B-Cell Dysfunction

Here we present evidence for previously unappreciated B-cell immune dysregulation during acute Epstein-Barr virus (EBV)-associated infectious mononucleosis (IM). Longitudinal analyses revealed that patients with acute IM have undetectable EBV-specific neutralizing antibodies and gp350-specific B-cell responses, which were associated with a significant reduction in memory B cells and no evidence of circulating antibody-secreting cells. These observations correlate with dysregulation of tumor necrosis factor family members BAFF and APRIL and increased expression of FAS on circulating B cells.

Cytokine-Mediated Loss of Blood Dendritic Cells During Epstein-Barr Virus-Associated Acute Infectious Mononucleosis: Implication for Immune Dysregulation

Acute infectious mononucleosis (IM) is associated with altered expression of inflammatory cytokines and disturbed T-cell homeostasis, however, the precise mechanism of this immune dysregulation remains unresolved. In the current study we demonstrated a significant loss of circulating myeloid and plasmacytoid dendritic cells (DCs) during acute IM, a loss correlated with the severity of clinical symptoms. In vitro exposure of blood DCs to acute IM plasma resulted in loss of plasmacytoid DCs, and further studies with individual cytokines showed that exposure to interleukin 10 could replicate this effect. Our data provide important mechanistic insight into dysregulated immune homeostasis during acute IM.

Low oxygen exposure does not cause pulmonary injury in the newborn rat

BACKGROUND

Two recent studies have suggested that low levels of supplemental inspired oxygen may cause lung injury in preterm infants.

AIMS

To assess lung injury of newborn rats exposed to 14 days of low-level variation of oxygen.

STUDY DESIGN

Four groups were compared with 12 animals per group and 4 lung sections per animal. These were, a control group raised in room air and three groups raised in levels of inspired oxygen fluctuating around the following mean values: group Lo (mean FiO(2) 0.179), group N (mean FiO(2) 0.213), and group Hi (mean FiO(2) 0.247). The degree of oxygen variability was identical for each group. Lungs were inflated at 20 cm H(2)O, fixed and stained with H and E and Millers Elastin.

SUBJECTS

Sprague Dawley albino newborn rats.

OUTCOME MEASURES

Random alveolar areas were studied and analysed using imaging software to assess total amount of tissue and elastin, number of secondary septa, and mean linear intercept.

RESULTS

There were no significant differences between the three experimental oxygen groups and the control group in terms of lung/body weight ratio and the measured markers of lung development.

CONCLUSION

We conclude that low-level oxygen supplementation during early lung development does not affect alveolar development in the newborn rat.

Activation of CD40 in Cervical Carcinoma Cells Facilitates CTL Responses and Augments Chemotherapy-Induced Apoptosis

In this study, we describe the expression and function of CD40, a TNF receptor family member, in cervical carcinomas. CD40 was present at very low levels in normal cervical epithelium but was overexpressed in human papillomavirus-infected lesions and advanced squamous carcinomas of the cervix. The stimulation of CD40-positive cervical carcinoma cell lines with soluble CD40L (CD154) resulted in activation of the NF-kappaB and MAPK signaling pathways and up-regulation of cell surface markers and intracellular molecules associated with Ag processing and presentation. Concomitantly, the CD154-induced activation of CD40 in carcinoma cells was found to directly influence susceptibility to CTL-mediated killing. Thus, CD40 stimulation in cervical carcinoma cell lines expressing a TAP-dependent human papillomavirus 16 E6 Ag epitope resulted in their enhanced killing by specific CTLs. However, CD154 treatment of carcinoma cells expressing proteasome-dependent but TAP-independent Ags from the EBV-encoded BRLF1 and BMLF1 failed to increase tumor cell lysis by specific CTLs. Moreover, we demonstrate that chemotherapeutic agents that suppress protein synthesis and reverse the CD40-mediated dissociation of the translational repressor eukaryotic initiation factor 4E-binding protein from the initiation factor eukaryotic initiation factor 4E, such as 5-fluorouracil, etoposide, and quercetin, dramatically increase the susceptibility of cervical carcinoma cells to CD40L-induced apoptosis. Taken together, these observations demonstrate the functional expression of CD40 in epithelial tumors of the cervix and support the clinical exploitation of the CD40 pathway for the treatment of cervical cancer through its multiple effects on tumor cell growth, apoptosis, and immune recognition.

Herpesvirus-Specific CD8 T Cell Immunity in Old Age: Cytomegalovirus Impairs the Response to a Coresident EBV Infection

Aging in humans is associated with increased infections and the reduced proliferative capacity of T cells, part of the more global phenomenon termed immune senescence. The etiology of immune senescence is unknown but the accumulation of virus-specific memory T cells may be a contributory factor. We have examined CD8 T cell responses to two persistent herpesvirus infections, CMV and EBV, and to a recurrent virus infection, influenza, in different age cohorts of healthy donors using HLA-peptide tetramers and intracellular cytokine detection. Of these, CMV appears to be the most immunogenic, with the CD8 T cell response representing over 10% of the CD8 pool in many elderly donors. Interestingly, the effect of age upon EBV-specific responses depends upon donor CMV sero-status. In CMV seropositive donors, the magnitude of the EBV-specific immune response is stable with age, but in CMV seronegative donors, the response to EBV increases significantly with age. By contrast, the influenza-specific CD8 T cell immune response decreases with age, independent of CMV status. The functional activity of the herpesvirus-specific immune response decreases in elderly donors, although the characteristic phenotypes of CMV- and EBV-specific memory populations are retained. This demonstrates that aging is associated with a marked accumulation of CMV-specific CD8 T cells together with a decrease in immediate effector function. Moreover, infection with CMV can reduce prevailing levels of immunity to EBV, another persistent virus. These results suggest that carriage of CMV may be detrimental to the immunocompetent host by suppressing heterologous virus-specific immunity during aging.

Frequent recognition of BCRF1, a late lytic cycle protein of Epstein-Barr virus, in the HLA-B*2705 context: evidence for a TAP-independent processing

Using a transient COS transfection assay, allowing a rapid estimation of the dominant CD8(+) T cell responses against a large number of HLA/viral protein combinations within polyclonal cell lines, we searched for HLA-B*2705-restricted CD8 T cell responses to Epstein-Barr virus (EBV) within T cell samples enriched for EBV-reactive cells. Among the 18 EBV proteins tested, only 2, the latent protein EBNA3A and the late lytic protein BCRF1 (viral IL-10), appeared dominant in the B27 context, as they triggered significant TNF and cytolytic responses in some donors. We provide evidence that the B27/BCRF1 epitope (RRLVVTLQC) is located in the signal sequence and that it can be presented in a TAP-independent manner. Using B27/BCRF1 monomeric complexes coated on immunomagnetic beads, we sorted out BCRF1-specific CD8 T cells from 8 of 15 HLA-B27(+) donors. This is, to our knowledge, the first demonstration of a recognition of BCRF1, suggesting that some immune control against EBV exists even during the late stage of the lytic cycle. This result also strengthens the unusual ability of HLA-B*2705 to present peptide in a TAP-independent manner.

The flow cytometric analysis of telomere length in antigen-specific CD8+ T cells during acute Epstein-Barr virus infection

Acute infectious mononucleosis (AIM) induced by Epstein-Barr virus (EBV) infection is characterized by extensive expansion of antigen-specific CD8+ T cells. One potential consequence of this considerable proliferative activity is telomere shortening, which predisposes the EBV-specific cells to replicative senescence. To investigate this, a method was developed that enables the simultaneous identification of EBV specificity of the CD8+ T cells, using major histocompatibility complex (MHC) class I/peptide complexes, together with telomere length, which is determined by fluorescence in situ hybridization. Despite the considerable expansion, CD8+ EBV-specific T cells in patients with AIM maintain their telomere length relative to CD8+ T cells in normal individuals and relative to CD4+ T cells within the patients themselves and this is associated with the induction of the enzyme telomerase. In 4 patients who were studied up to 12 months after resolution of AIM, telomere lengths of EBV-specific CD8+ T cells were unchanged in 3 but shortened in one individual, who was studied only 5 months after initial onset of infection. Substantial telomere shortening in EBV-specific CD8+ T cells was observed in 3 patients who were studied between 15 months and 14 years after recovery from AIM. Thus, although telomerase activation may preserve the replicative potential of EBV-specific cells in AIM and after initial stages of disease resolution, the capacity of these cells to up-regulate this enzyme after restimulation by the persisting virus may dictate the extent of telomere maintenance in the memory CD8+ T-cell pool over time.

Nucleotide sequence of the Barmah Forest virus genome

Barmah Forest virus (BFV) is an atypical alphavirus [Dalgarno, L., Short, N. J., Hardy, C. M., Bell, J. R., Strauss, J. H., and Marshall, I. D. (1984). Virology 133, 416-426] and has been classified as the sole known member of a seventh alphavirus serocomplex. The complete nucleotide sequence of BFV genomic RNA is 11,488 nucleotides in length excluding the poly(A) tail. Two long open reading frames in the RNA encode a nonstructural polyprotein of 2411 amino acids and a structural polyprotein of 1239 amino acids, respectively. The BFV envelope protein E2 is unique among sequenced alphaviruses in having no N-linked glycosylation sites; E1 carries two glycosylation sites. From amino acid sequence comparisons with sequenced alphaviruses BFV is most closely related to Ross River and Semliki Forest viruses. Sequence homology between BFV and other alphaviruses is relatively uniform along the length of the nonstructural and structural polyproteins, providing no evidence that BFV has arisen from recombination between ancestral alphaviruses in the coding region of the genome. The BFV 3' noncoding region of 445 nucleotides has unusual features. There are two unrelated sequence blocks of 48 nucleotides (sequence I) and 47 nucleotides (sequence II) both of which are repeated once. Sequence I is closely related to a repeat in the 3' noncoding region of Ross River and Getah viruses; sequence II is unrelated to repeat blocks in other sequenced alphaviruses. Thus, recombination between ancestral viruses may have played a role in the evolution of the BFV 3' noncoding region.

Characterization of muscarinic receptor subtypes in pig airways: radioligand binding and northern blotting studies

This study was undertaken to characterize the muscarinic receptor subtypes present in adult pig peripheral lung and airway smooth muscle. The binding of the nonselective muscarinic antagonist [N-methyl-3H]scopolamine ([3H]NMS) to pig airways showed a single class of binding sites with a maximum density of 172 and 450 fmol/mg protein in peripheral lung and airway smooth muscle, respectively. Unlike [3H]NMS, the M1-selective antagonist, [3H]telenzepine, recognized two populations of binding sites in peripheral lung. Approximately 14% of total [3H]telenzepine binding sites displayed high affinity [dissociation constant (Kd) = 0.95 nM], whereas the remaining sites showed low affinity (Kd = 14.2 nM). The high- and the low-affinity [3H]telenzepine binding sites displayed the pharmacological profile of M1 and M2 receptors, respectively. Heterogeneity of pig airways muscarinic receptor was also revealed by competitive binding experiments against [3H]NMS with the M2-selective antagonist methoctramine. This compound recognized 70 and 90% of total receptors with high affinity in airway smooth muscle (Ki = 4.44 nM) and peripheral lung (Ki = 9.82 nM), respectively. This result suggests that the dominant muscarinic receptor in pig airways is of the M2 subtype. Northern blot analysis demonstrated the presence of m1 and m2 mRNAs transcripts in peripheral lung and m2 and m3 mRNAs in airway smooth muscle with no evidence for m4 mRNA.

Surgical factors affecting growth potential of the immature rat lung

The transplanted immature rat lung has been shown capable of fulfilling its growth potential after left lung transplantation (LLTx) and concomitant right cardiac lobe resection (RCLR). However, unexpected findings in these studies included an abnormal rise in lung volume in the contralateral lung due to alveolar multiplication, and significant dilatation of the bronchi in the transplanted left lung. In the present study, the influence of surgical factors that could have contributed to these changes, i.e. RCLR, denervation, and anastomotic stenosis, were studied individually. Immature Lewis rats aged 4 and 6 weeks were used and (a) RCLR, (b) RCLR and right hilar stripping, and (c) RCLR and left pulmonary artery (PA) banding were performed in groups 1 (n = 12), 2 (n = 5) and 3 (n = 6), respectively. Animals were killed after 6 months and the lungs studied using quantitative morphometric techniques. In groups 1 and 2, right lungs did not show any significant increase in volume. Alveolar number and airway diameter in both lungs in all groups were not significantly different from controls. In group 3 both right and left lungs presented an increase in alveolar size (p less than 0.02 on the right and p less than 0.01 on the left). Changes seen after LLTx in the rat, such as alveolar multiplication, cannot be explained by compensatory growth (RCLR), denervation (RCLR and hilar stripping), or arterial stenosis at the anastomotic site (RCLR and left PA banding), but must be regarded as a consequence of transplantation per se. A role for neuropeptides in lung growth following transplantation is suggested.

The effect of amniocentesis and drainage of amniotic fluid on lung development in Macaca fascicularis

Amniocentesis and withdrawal of amniotic fluid was performed on pregnant monkeys (Macaca fascicularis) at two stages in development, either between 47 and 64, or between 85 and 95 days gestation. After birth the lungs of each infant monkey were studied using precise morphometric techniques, and compared with those in a control group of animals. The lungs after amniocentesis had alveoli of normal maturity but reduced in number and increased in size, features which both reduce the relative area for gas exchange. There was also a reduction in the number of respiratory airways. These changes occurred regardless of the time of amniocentesis, the amount of fluid removed and even if the membranes were simply punctured with no fluid removal. There is some evidence to suggest that similar sublethal effects may be present in human infants after maternal amniocentesis.

Morphometric studies on the structural development of the lung in Macaca fascicularis during fetal and postnatal life

The structural development of the normal monkey lung (Macaca fascicularis) from 61 days of gestation to 14 days postnatal age has been described using quantitative morphometric techniques. The lung of the adult monkey has also been studied. The airway and arterial branching pattern has been traced using serial sections. The alveolar number and size have been estimated and the structure of the arteries after postmortem arterial injection has been assessed. Comparison of lung morphology in monkey and man shows that there are similarities in segmental arrangement, structure and branching pattern of airways, in arterial structure and in changes in the arteries after birth. Although there are differences in the number of lobes, the number of generations of different types of airways and the number and size of alveoli, the overall structure in the monkey is more similar to that in man than is the structure of the lung in species such as sheep, pig or rat. During fetal life the monkey lung passes through the same stages of development as the human fetus but at birth the monkey has a full complement of airways and mature alveoli. Postnatal growth of airways and alveoli is due to increase in size rather than to multiplication. In man there is an increase in the number of alveoli and alveolar ducts after birth as well as an increase in size. Despite the differences between the species it seems appropriate to use the monkey in experimental studies on the lung.

The lungs in congenital bilateral renal agenesis and dysplasia

A detailed quantitative analysis was made of the lungs from 8 infants dying with bilateral renal agenesis or dysplasia. Total lung volume was reduced in all cases, particularly in those with renal agenesis. In both groups there was a reduction in number of airway generations, indicating interference with development at between 12 and 16 weeks' gestation. The alveoli in each acinus were reduced in size and, in some cases, number--although their stage of differentiation was normal for age--pointing to a disturbance of growth during later fetal life also. As liquor is largely non-renal in origin at least up to 16 weeks' gestation, it seems that there are factors other than the oligohydramnios interfering in early lung growth in these cases, such as reduced proline production by the kidney.

Pulmonary arteries of the normal rat: the thick walled oblique muscle segment

The structure and certain metrical features of the pulmonary arterial tree in the normal rat have been studied in detail by both light and electron microscopy after its distension by injection. In the parts of the tree where the muscle wall is complete a segment with oblique muscle has been identified. The wall of this segment is thick, and is composed largely of obliquely orientated, closely packed smooth muscle cells with little intervening connective tissue, while it lacks a complete external elastic lamina. Both the axial pathway and its side branches have such oblique segments. Proximal and distal to an oblique segment there are transitional regions where obliquely arranged muscle fibres spiral external to the circularly arranged fibres usually described in muscular arteries. The existence of thick walled oblique muscle segments in the pulmonary arterial tree of the normal rat is important since this animal is frequently used in experimental studies, and the thick segments could be taken as evidence of induced hypertrophy.

Normal structure and dimensions of the pulmonary arteries in the rat

The normal structure and pattern of branching of the pulmonary arteries of the rat have been described and quantified, using precise morphometric techniques, after injection of the pulmonary arteries with a radio-opaque medium. Rats of the same strain from three different sources have been compared, and similarities between rat and man have been assessed. In rat, as in man, the pulmonary artery accompanies the airway and branches with it and, in addition, there are extra arterial branches. Most arteries within the rat lung are muscular and have no more than two central elastic laminae. The percentage wall thickness of the muscular arteries is between 1 and 3%, similar to that found in adult human lungs. At the periphery of the arterial tree there is a mixed population of muscular, partially muscular and non-muscular arteries. The distribution by size is similar in man and rat, but there are few wholly muscular arteries within the acinar region in the rat. The similarity of the features of the pulmonary arteries of rat and man makes the rat a suitable experimental animal for study of changes in pulmonary hypertension. However, any change must be interpreted in relation to arterial structure in normal rat lungs from the same source, since some significant differences have been found between rats from different sources in respect of wall thickness and number of vessels.

Changes in the pulmonary arteries of the rat during recovery from hypoxia-induced pulmonary hypertension

Pulmonary hypertension has been induced in rats by 2 weeks' exposure to hypoxia, equivalent to an altitude of approximately 5500 m, in a hypobaric chamber. The rats were removed from the chamber and allowed to recover for up to 8 weeks at atmospheric pressure. Precise quantitative microscopic techniques after injection of the pulmonary artery have been used to estimate the regression in the pulmonary artery of the structural changes associated with pulmonary hypertension. During recovery the degree of muscularization of the pulmonary arteries decreases by disappearance of muscle cells from the small arteries and a drop in arterial wall thickness of larger vessels. These changes do not seem to reflect pulmonary artery pressure directly, since right ventricular hypertrophy regresses at a faster rate. In hypertensive rats there is a "loss" of small arteries in the alveolar region and little filling of precapillary vessels. On recovery, some of the vessels fill, suggesting that encroachment on the lumen by muscle and endothelial cells has lessened. Even after 8 weeks' recovery, however, some arteries do not return, suggesting they have completely disappeared and that regions are left with relatively little perfusion. This reduction of vascular reserve presents without there being right ventricular hypertrophy.

Pulmonary hypoplasia in babies with severe rhesus isoimmunisation: a quantitative study

Analysis of lung weights of 96 infants dying with rhesus isoimmunisation has shown that the lung is considerably retarded in its growth. Detailed analysis of the lungs of six babies after pulmonary artery injection showed in all a reduction in airway number and thus acinar and artery number, suggesting arrest in growth before the 16th week of gestation. The alveoli were also of either abnormal number, size or maturity, suggesting a continuing effect in later foetal life. Total lung volume varied from the normal value in one case to one-quarter normal in the smallest lung.

New findings in pulmonary arteries of rats with hypoxia-induced pulmonary hypertension

Rats have been kept in a hypobaric chamber, and thus hypoxic, for up to 28 days in order to study the structural changes in the pulmonary arteries during the development of pulmonary hypertension. Rats were studied after 3, 5, 7, 10, 14, 21 and 28 days at a pressure of 380 mmHg. Right ventricular hypertrophy was demonstrated after 5 days in the hypoxic environment but increased up to 10 days. After pulmonary arterial injection microscopic counts of small arteries showed that vessels up to 200 mum external diameter were gradually "lost", reducing the ratio of arterial to alveolar number significantly by 14 days. No vestiges of these vessels were found with light microscopy. At the same time a gradual increase in arterial wall thickness was demonstrated and also progressive extension of muscle into smaller and more peripheral vessels than normal. In both these features maximum increase was reached by 14 days of exposure though changes were apparent after only 3. Similar changes have been found in patients with cystic fibrosis and chronic bronchitis using the same measuring techniques.

Persistent hypoplasia of the lung after repair of congenital diaphragmatic hernia

Quantitative analysis has been used to assess growth in a lung from an infant aged 21/2 months in whom a diaphragmatic hernia was repaired at birth. The lungs had been abnormally small at birth but at 21/2 months were of normal volume. Alveoli had multiplied at the normal rate after birth but had not reached the number normal of age. The number per acinus was normal but the alveoli were increased in size, particularly in the left lung. The airway number, and thus alveolar, acinar, and arterial number, were all reduced in both lungs, the ipsilateral being most affected. The pulmonary blood vessels in both lungs showed an increased muscularity that did not correlate with lung volume or alveolar number, a feature that may have been present at birth. The degrees of hypoplasia in the two lungs were different at birth and this difference had been maintained. The effect of the disturbance to lung growth on the functioning of the lung is discussed.

Quantitative structural analysis of pulmonary vessels in isolated ventricular septal defect in infancy

Structural changes in the pulmonary circulation were studied in the lungs of 5 infants dying with ventricular septal defect. Applying precise quantitative morphological techniques to the pulmonary vessels, it was possible to correlate pathological change with clinical and haemodynamic findings, and to identify two patterns of response. Three of the infants (group I) ppresnted in cardiac failure with a large pulmonary blood flow, dilated and tortuous pulmonary arteries, and fewer intra-acinar vessels than normal. Medial hypertrophy was moderate and affected chiefly the larger arteries, i.e. those with a diameter greater than 200 mum. The other 2 infants (group 2) had a high pulmonary vascular resistance with an intermittent right-to-left shunt. The pulmonary arteries were of normal size and the reduction in the number of the arteries was less striking. Medial hypertrophy was greater than in the first group and affected all sizes of artery including those less than 200 mum in diameter. In both groups, muscle extended further along the axial pathway. Muscular hypertrophy was found also in the vein wall in most cases and, as with the arteries, was more severe in those with a higher pulmonary vascular resistance. The findings illustrate the variation in pulmonary vascular response in infants with a ventricular septal defect. It is suggested that in patients with a ventricular septal defect, arterial muscularity usually regresses after birth and a left-to-right shunt develops; secondary hypertrophy of the media then develops in reaponse to the shunt. Our findings also suggest, however, that in some infants arterial muscle fails to regress postnatally so that pulmonary blood flow is never high and a right-to-left shunt develops soon after birth.

Arterial changes in Crotalaria spectabilis-induced pulmonary hypertension in rats

Pulmonary hypertension has been induced in rats by feeding them the seeds of Crotalaria spectabilis for 34 days, when some were killed and others left to recover for 14, 31 or 54 days. By 34 days and after pulmonary arterial injection, right ventricular hypertrophy was demonstrated with an increase in pulmonary arterial medial muscle, a reduced number of small arteries and “ghost” arteries. With recovery, right ventricular hypertrophy had regressed by 31 days and by 54 days the arterial muscle was decreased. There was no increase in number of small arteries although “ghost” arteries had disappeared by 31 days. Similar features have recently been described in human primary pulmonary hypertension.

Development of the acinus in the human lung

Hislop, Alison, and Reid, Lynne (1974).Thorax, 29, 90-94. Development of the acinus in the human lung. Development and remodelling of the acinus (those structures distal to the terminal bronchiolus) occurs during fetal life and childhood. Multiplication of the acinar air spaces and the structural changes they undergo have been described and represented schematically by summarizing previous studies, particularly those of the last two decades.

Most acinar airways are present before birth. Future respiratory bronchioli are represented by the 19th intrauterine week; alveolar ducts are present as saccules by the 28th week. Alveolar sacs and alveoli, as properly described, do not appear until after birth: alveoli increase in number, particularly in the first seven or so years of life, and in size with thoracic growth.

Structural changes in the pulmonary arteries and veins in tetralogy of Fallot

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Unilateral congenital dysplasia of lung associated with vascular anomalies

Hislop, A., Sanderson, M., and Reid, L. (1973).Thorax, 28, 435-441. Unilateral congenital dysplasia of lung associated with vascular anomalies. In three cases of unilateral lung dysplasia the structural changes have been analysed quantitatively to throw light on the nature of the anomaly and stage of its appearance. In one case the pulmonary artery was hypoplastic and the systemic supply normal but increased, suggesting onset in late intrauterine life or early childhood: in the other two cases the blood supply was only systemic, from both normal and abnormal arteries, suggesting onset in the early weeks of intrauterine development. Airway development was consistent with this interpretation. All cases had additional signs of maldevelopment of mesodermal tissue. The origin of the various types of systemic artery is discussed.

Fetal and childhood development of the intrapulmonary veins in man--branching pattern and structure

The drainage pattern and the structure of the pulmonary veins have been described quantitatively in a series of fetal and child lungs after injection of the veins with a radio-opaque medium. The drainage pattern of the pre-acinar region is complete by half-way through gestation and corresponds with the growth of the pulmonary arteries. There is new growth of veins within the acinus during childhood. Four types of veins arising from five peripheral sites have been described. The change in dimensions with age have also been measured. A measurable muscle layer could not be found in the walls of the veins before birth though some muscle cells were present from 28 weeks of gestation. The thickness of the muscle coat in any vein was similar at birth and in a 3- and 10-year-old child and in all cases was less than in a pulmonary artery of the same size. The muscle cells were of smaller diameter in the veins than in the arteries. Along any venous pathway between a non-muscular and muscular structure was a region where part of the wall was muscular: these veins were termed partially muscular. Their distribution by size was similar at all ages.

Pulmonary arterial development during childhood: branching pattern and structure

In lungs from 18 children aged between birth and 11 years the development of the branching pattern and structure of the pulmonary arteries, particularly the intralobular and intra-acinar, has been quantitatively analysed after injection with a radio-opaque medium. Up to 18 months of age as new alveolar ducts appear conventional arterial branches develop within the acinus: supernumerary arteries increase in number up to 8 years as new alveoli form. Both types increase in size with age.

After birth there is an immediate drop in wall thickness of the vessels below 200 μm diameter while the larger vessels take up to 4 months to fall to adult thickness, suggesting two types of response—one dilatation, the other a growth rate change of the muscle cells. During childhood muscle cell formation in the intra-acinar arteries lags behind increase in artery size so that during childhood few muscular arteries are found within the acinus. The functional significance of these changes is discussed.

Weight of the left and right ventricle of the heart during fetal life

The hearts from 31 fetuses aged from 12 to 40 weeks' gestation were dissected after fixation. The right ventricle and the left ventricle plus septum were weighed separately and a ratio was established. The total and separate ventricular weights increase steadily with age and at a similar rate. Throughout fetal life the left ventricle plus septum is larger than the right ventricle, but the right ventricle forms a greater proportion of the total ventricular weight than it does in the child or the adult.For the first time, a table of normal fetal heart weights and ratios obtained using the method of Fulton, Hutchinson, and Jones (1952) is presented.

Postnatal growth and function of the pre-acinar airways

The postnatal growth of the pre-acinar or conducting airways of the lung was examined by measuring the dimensions of selected axial pathways in lungs at different stages of development. The material included both formalin-fixed specimens and bronchograms. A method of comparing the relative sizes of each part of the pathways was developed which allowed for differences between the number of branches or generations measured in each specimen. The results indicate that the pre-acinar airways of the infant may be regarded as a miniature version of those in the adult and that this relationship persists during postnatal growth. Each individual branch grows in a symmetrical fashion both in length and in diameter and bears a constant relation to the whole. The physiological function of the conducting airways during growth was investigated using published data on the breathing pattern of infants. Particular attention was given to the conditions of airflow, to the warming and humidification of inhaled air, and to the filtration of airborne dust.

Lung hypoplasia in congenital diaphragmatic hernia. A quantitative study of airway, artery, and alveolar development

From a case of congenital diaphragmatic hernia the pattern of growth of the airways, alveoli, and pulmonary arteries of both lungs, each hypoplastic, has been analysed quantitatively. The impairment of growth for each type of structure is not necessarily the same and differs in each lung. Airway and alveolar numbers are both greatly reduced, although the latter are more nearly normal when related to the number of terminal bronchioli in the lung. In each lung the size of the pulmonary artery at the hilum is appropriate to the lung volume but small for the age of the child. Muscle is found in much smaller arteries than is normal but not to a more peripheral level.

The way the lungs in a case of congenital diaphragmatic hernia might grow after surgical correction of the hernia is discussed and a plea made for respiratory physiological studies in such cases.

New pathological findings in emphysema of childhood. 2. Overinflation of a normal lobe

A quantitative study of the structure of the affected lobe from a patient with childhood lobar emphysema is here reported. The left upper lobe was removed from a child aged 2½ months who was suffering from acute respiratory distress and showing on his radiograph hypertransradiancy of the left lung.

At operation the lobe was found to be increased in volume and rotated through 180° on its pedicle. After laboratory injection of some of the pulmonary artery branches and distension of the lobe, the stage of development of the various lung structures was studied quantitatively. The arteries and bronchi were normal in number and structure: the alveolar number was normal for the age of the child but the volume of an alveolus was increased four to five times, as was total lung volume.

The antenatal development of this lobe was normal and it seems that the emphysema could have followed the rotation of the lobar hilum, although no cause for this rotation was found.

New pathological findings in emphysema of childhood. 3. Unilateral congenital emphysema with hypoplasia--and compensatory emphysema of contralateral lung

A quantitative study is here reported on the lungs of a child of 9 months with unilateral emphysema associated with hypoplasia, and with compensatory emphysema in the contralateral lung. The left lung was judged to show congenital hypoplasia because of the reduced number of bronchi and arteries, its small volume, and a total alveolar number less than that normally found at birth. This last was due mainly to reduction in the number of acini, the intra-acinar number seeming little affected. As the alveoli were eight times the normal volume, the case was considered to be one of congenital hypoplastic emphysema.

The right lung was evidently normal at birth, since it had a normal number of bronchi, arteries, and alveoli. The lung was increased in volume due to an increase in alveolar volume—an example of compensatory emphysema.

This case is discussed with relation to two previously reported cases of lobar emphysema and other cases in the literature. It is emphasized that a quantitative analysis of the state of bronchi, alveoli, and blood vessels is important to establish the nature of the pathological change. A preliminary classification based on the anatomical features is offered.

New pathological findings in emphysema of childhood. 1. Polyalveolar lobe with emphysema

A new pathological entity is here described—a polyalveolar lobe with or without emphysema—giving rise to the clinical features of childhood lobar emphysema.

A detailed and quantitative study of the airways, alveoli and arteries was carried out on the left upper lobe removed because of shortness of breath, thought to be due to `childhood lobar emphysema'. The child was 17 days old and the radiograph showed hypertransradiancy of the left lung. The alveolar number was increased five-fold. Alveolar size was normal, so it was found that emphysema, accepted today as a structural diagnosis, was not present. The increase in alveolar number seemed confined to the apical, posterior, and anterior segments, the lingula being unaffected. By contrast, the airways and arteries were normal for age in number, size and structure, suggesting that the condition was a `giantism' of the alveolar region. The blood flow was probably too low for the lobar volume; certainly the excessive alveolar number could not be due to increase in blood flow.

In two further specimens, previously dissected, a similar polyalveolar condition was found, associated with emphysema. The patients were older at the time of surgical resection and the emphysema may have developed post-natally. In all three cases the radiographic features had suggested emphysema. It is suggested that the condition be called `polyalveolar lobe', `with emphysema' or `without emphysema' being added as a separate item to the description.