Parents’ perception of overweight-obese children Quality of Life in different settings

Background

Children's Health-Related Quality of Life (HRQoL) has been frequently investigated, in particular among individuals affected by chronic diseases. It is reported that agreement between child and parent ratings regarding the child's HRQoL is strongly influenced by the latter's health status. To our knowledge, there is no evidence of how this agreement is related to different healthcare settings. Thus, our study aims to examine the relationship between child's and parent-proxy reported HRQoL of similar overweight/obese children according to the recruitment setting.

Methods

A cross-sectional study was conducted among 68 overweight/obese children, aged 6-10, recruited in a primary school (Group1, G1) and in a hospital outpatient clinic (Group2, G2) of Imola (Italy) in 2019. HRQoL was assessed using Italian version 4.0 of the Pediatric Quality of Life (PedsQL) questionnaire. For each child, we obtained self-reported children's and parents' perceived children's HRQoL total score (5 questions investigating Physical Health domain and 10 questions investigating Psychosocial Health domain divided in Emotional, Social and School Functioning).

Results

In G1 there were n = 42 overweight/obese children and in G2 n = 26. The correlation between children's reported and parents' perceived HRQoL scores is lower in G1 (Physical Health: r=-0,17; Psychosocial Health: r = 0.38) compared to G2 (Physical Health: r = 0.80; Psychosocial Health: r = 0.66). Notably, in G1, parents tend to overestimate their children's HRQoL, specifically in the Physical Health domain.

Conclusions

Correlation between children's and parents' HRQoL scores is higher in the clinical setting compared to the school setting. Implementing this questionnaire on a large scale would allow us to identify settings which need awareness-raising initiatives to improve parents' knowledge about their children's health.

Key messages

Parents’ overestimate children’s HRQoL in the school setting, particularly in the Physical Health domain. Children’s HRQoL misinterpretation might determine less targeted actions to improve their wellbeing and highlights the need for raising parents’ awareness about obesity and its effects on children.

Small-scale spatial analysis shows the specular distribution of excess mortality between the first and second wave of the COVID-19 pandemic in Italy

OBJECTIVES

The objective of the study is to compare excess mortality (EM) patterns and spatial correlation between the first and second wave of the pandemic in Lombardy, the Italian region that paid an extremely high COVID-19-related mortality toll in March and April 2020.

STUDY DESIGN

We conducted a longitudinal study using municipality-level mortality data.

METHODS

We investigated the patterns and spatial correlation of EM of men aged ≥75 years during the first two pandemic waves (March-April 2020 vs November 2020) of COVID-19, using the mortality data released by the Italian National Institute of Statistics. EM was estimated at the municipality level to accurately detect the critical areas within the region.

RESULTS

The areas that were mostly hit during the first wave of COVID-19 were generally spared by the second wave: EM of men aged ≥75 years in the municipality of Bergamo plummeted from +472% in March and April to -13% in November, and in Cremona the variation was from +344% to -19%. Conversely, in November 2020 EM was higher in some areas that had been protected in the first wave of the pandemic. Spatial correlation widely corroborates these findings, as large sections of the hot spots of EM detected in the first wave of the pandemic changed into cold spots in the second wave, and vice versa.

CONCLUSIONS

Our results reveal the specular distribution of EM between the first and second wave of the pandemic, which may entail the consequences of social distancing measures and individual behaviors, local management strategies, 'harvesting' of the frailer population and, possibly, acquired immune protection. In conclusion, our findings support the need for continuous monitoring and analysis of mortality data using detailed spatial resolution.

The contribution of case mix, skill mix and care processes to the outcomes of community hospitals

Background

The rapid increase in the proportion of older people underscores the need for new organizational models to face the unmet needs of frail patients with multiple conditions. Community hospitals (CHs) could be a solution to tackle these needs and foster integration between acute and primary care. The aim of this study was to investigate which patients' characteristics and which care processes affect clinical outcomes, in order to identify who could benefit the most from CH care and the best skill mix to deliver in this setting of care.

Methods

This study included all patients aged ≥65 and discharged in 2017 from the 16 CHs of Emilia-Romagna, northern Italy. Data sources were the regional CH informative system and hospital discharge records. CH skill mix and processes of care were collected with a survey; 3 non-respondent CHs were excluded. The study outcome was in-hospital variation of the Barthel index (BI) (≥10 vs. <10). We performed a 2-level random-intercept logistic regression analysis, and used the variance partition coefficient (VPC) to quantify the proportion of BI improvement that lay at CH level.

Results

Of the 13 CHs, 7 admitted ≥150 patients, 8 had a general practitioner medical support model, and 6 had >12 nurses' working hours/week/bed. Overall, 53% of the patients had a BI improvement ≥10 (4% to 71% across CHs). The patient case mix (i.e. baseline BI, female, older age, transfer from acute care) explained a portion of variability across CHs, as shown by the VPC that decreased from 0.32 to 0.26. Skill mix and processes of care were not associated with BI change, and the VPC resulting from controlling for these variables was virtually unchanged (0.28).

Conclusions

Patients' characteristics explained part of between-CH variation in BI improvement. Professional skill mix and processes of care, albeit fundamental to achieve appropriate care and respond to the unmet needs of the frail elderly, did not account for differences in CH-specific outcomes.

Key messages

A combination of quantitative and qualitative methods might better explain the outcome variability across intermediate care services. Multidisciplinary CH teams and services can be helpful to address the unmet needs of older people, but further studies are necessary.

Mortality amenable to health care services and health inequalities across the regions of Italy

Background

Amenable mortality is an indicator that measures the extent to which health services contribute to the improvement of the health of a population. It can also highlight geographical and socioeconomic inequalities. Therefore, it is used to assess quality and performance of health care systems, both at national and subnational level. The Italian National Health Service sets the essential levels of care (Livelli Essenziali di Assistenza, LEA), a health-benefit package for all citizens. Because every region is responsible for providing the LEA and can offer additional health care, monitoring the performance of the Regional Health Services (RHSs) is of increasing interest.

Methods

We used Nolte and McKee's list of amenable conditions to analyze the temporal trend of the standardized mortality rate (per 100.000) in Italy from 2006 to 2015, overall and by gender. We also examined the standardized rate at regional level by comparing the two-year periods 2006/7 and 2014/5, overall and by gender.

Results

Between 2006 and 2015, the overall mortality rate decreased from 81 to 68 per 100.000 population; this reduction was more pronounced in men (91 to 76 per 100.000, -16.5%) than in women (72 to 62 per 100.000, -13.9%). The decreasing trend in amenable mortality affected Italian regions differently, with northern regions showing steeper reductions as compared to southern regions. As a result, 2014/5 was the first time men's mortality in North Italy (68 per 100.000) was lower than women's mortality in South Italy (72 per 100.000).

Conclusions

The overall reduction of amenable mortality shows that Italy's health care services keep contributing to the improvement of population health. Nevertheless, by analyzing RHS performance we saw that differences in organization of care lead to differences in health care quality and performance across regions. Deaths amenable to health care services contribute to inequalities between Northern and Southern Italy.

Key messages

Because universal health coverage is necessary but not sufficient to reduce health inequalities, investing into better-quality services should be recognized as a priority. Amenable mortality can highlight areas of intervention to reduce inequalities in the provision of health care services.

Is the firearm epidemic in the US getting worse?

Background

The US is the least regulated firearm market in the Western world and firearm violence is a major public health issue. Firearms account for 40,000 deaths in the US annually, which is higher than other high-income countries. Although most of the gun-related deaths in the US are the result of suicide attempts and self-inflicted injuries, nearly 40% of them come from accidents, assaults, or police intervention.

Methods

We measured the number of non-self-inflicted firearm-related ED visits, by including patients discharged with diagnostic ICD-9-CM (ICD-10 for 2016) codes of accidents, assaults or legal intervention resulting in firearm injuries between 2006-2016. We used data from the Healthcare Cost and Utilization Project (HCUPnet). From the CDC Wide-ranging Online Data for Epidemiologic Research we obtained data on non-suicidal firearm-related deaths over the period 2006-2017. To identify the cause of death we used the ICD-10 codes. Temporal changes of rates of ED visits and deaths were evaluated using Joinpoint Software.

Results

In 2006 there were a total of 79,998 ED visits with a diagnostic code of firearm-related injury, and this number showed a non-significant 2.7% annual decline between 2006-2013 (p = 0.06) followed by a significant 19.4% annual increase between 2013-2016 (p < 0.05), resulting in 111.305 visits in 2016. The number of non-suicidal firearm-related deaths showed a significant 2.2% annual decline between 2006-2014 (p < 0.05), followed by a significant 10.3% APC (p < 0.05) between 2014-2017.

Conclusions

Data showed steady rates until 2013 and a striking increasing trend starting from 2013. Firearm-related deaths followed the same trends. Our data show that in the last four detectable years there has been a new concerning wave of gun violence and consequently a higher number of fatalities. Analysis limitations: we used national-level aggregate data and coding accuracy may be not consistent nationwide.

Key messages

In the last four detectable years there has been a new concerning wave of gun violence and consequently a higher number of fatalities nationwide. The US firearm related deaths epidemic urges for new policies and preventive measures, such as stricter background checks and restrictions on guns ownership.

Assessment of mRNA Levels for Matrix Molecules and TGF-β1 in Rabbit Flexor and Peroneus Tendons Reveals Regional Differences in Steady-State Expression

This study analysed the differences on a molecular level between two segments of the deep flexor tendon, and compared the intrasynovial flexor tendon with the tendon sheath and the extrasynovial peroneus tendon in a rabbit model. The TRIspin method of RNA extraction was combined with the reverse transcription polymerase chain reaction to assess mRNA levels in the tissue segments. Significant differences were detected for all genes studied. mRNA levels for aggrecan, biglycan and collagen III were significantly higher in the fibrocartilaginous proximal segment of the flexor tendon. Collagen I was higher in the flexor tendon than the sheath and the peroneus tendon, and TGF-β1 was significantly lower in the peroneus tendon. This study demonstrates differences at the mRNA level between different segments of tendon, indicating that the tendon tissue may be adapted to its environment.

Growth factor and protease expression during different phases of healing after rabbit deep flexor tendon repair

The purpose of the study was to contribute to the mapping of molecular events during flexor tendon healing, in particular the growth factors insulin-like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF) and nerve growth factor (NGF), matrix metalloproteinases (MMP-3 and MMP-13) and their inhibitors (tissue inhibitors of metalloproteinases, TIMP-1 and TIMP-3, and the protease cathepsin K. In a rabbit model of flexor tendon injury, the mRNA expression for the growth factors, MMPs and TIMPs were measured in tendon and tendon sheath tissue at several time points (3, 6, 21, and 42 days) representing different phases of the healing process. We found that MMP-13 remained increased during the study period, whereas MMP-3 returned to normal levels within the first week after injury. TIMP-3 was down-regulated in the tendon sheaths. Cathepsin K was up-regulated in tendons and sheaths after injury. NGF was present in both tendons and sheaths, but unaltered. IGF-1 exhibited a late increase in the tendons, while VEGF was down-regulated at the later time points. In conclusion, we have demonstrated the presence of NGF in flexor tendons. MMP-13 expression appears to play a more protracted role in flexor tendon healing than MMP-3. The relatively low levels of endogenous IGF-1 and VEGF mRNA following injury support their potential beneficial role as exogenous modulators to optimize tendon healing and strength without increasing adhesion formation.

Skin wound healing in the first generation (F1) offspring of Yorkshire and red Duroc pigs: evidence for genetic inheritance of wound phenotype

Fibroproliferative scars in humans often demonstrate familial inheritance patterns, and genetics may contribute to healing and scarring. Genetic factors may also influence the scarring phenotype in a porcine model. Healing of full thickness excisional skin wounds in Yorkshire pigs closely resembles normal healing in humans, while identical wounds in red Duroc pigs form hypercontracted, hyperpigmented scars. The present study has evaluated the healing process in the first generation cross (F1) of red Duroc and Yorkshire pigs. Gross and histologic analysis revealed that the F1 animals exhibit an intermediate healing phenotype, with some features of each parent breed. F1 full thickness wounds were significantly hypercontracted and fibrotic, but apigmented. Analysis of mRNA expression patterns for a panel of relevant molecules (N=32) in the F1 animals revealed some similarities to each parent breed, as well as unique patterns for other molecules. Furthermore, a depth dependency to the healing response was observed at the gross, histologic, and molecular levels, with deep dermal wounds healing similar to Yorkshire wounds. These findings suggest that the genetic contribution to scar phenotype in this animal model is complex. However, the results indicate that further understanding in this model may provide insights into risk factors for hypertrophic scarring in human burn patients.

Age-dependent changes in the regulation of cyclooxygenases in the gastrointestinal tract after gram-negative endotoxemia

BACKGROUND

Cyclooxygenases (COXs) modulate prostaglandin synthesis in the gastrointestinal tract. Prostaglandins have been shown to have a cytoprotective effect on bowel mucosa in adults, but no similar data are available in neonates. Thus, the purpose of the current study was to evaluate age-dependent changes in gastrointestinal tract COX regulation after Escherichia coli lipopolysaccharide exposure in rats.

METHODS

Stomach, small bowel, and large bowel COX-1 and COX-2 mRNA levels (reverse transcription polymerase chain reaction technique) and protein content (Western blot) were obtained from neonates (younger than 3 days old) and adult rats 18 hours after exposure to E. coli O111:B4 lipopolysaccharide toxin. Untreated animals served as controls.

RESULTS

Stomach, small bowel, and large bowel tissue COX-1 mRNA levels in the newborn were significantly lower (P < 0.01) than in the adult. No age-dependent differences were found for COX-2 mRNA levels. After lipopolysaccharide exposure, no significant changes in COX-1 levels were seen at either age, whereas COX-2 mRNA levels were increased only in the stomach for both ages. Western blot analysis of small bowel tissue for COX-1 and COX-2 showed no lipopolysaccharide-induced changes in protein content, but the COX-1 content was significantly lower in the newborn (P < 0.01).

CONCLUSIONS

In the rat, COX expression in the gastrointestinal tract is regulated in an age-dependent fashion. Lower COX-1 expression and a lack of observable increase in COX-2 mRNA levels in the newborn small bowel after endotoxemia may render the bowel more susceptible to bowel injury early in life.

Expression of heat shock protein 47(Hsp47) mRNA levels in rabbit connective tissues during the response to injury and in pregnancy

Hsp47 (also termed "colligin") is a 47 kDa protein that is localized in the ER and cis-Golgi vesicles of fibrocytes, chondrocytes, and other collagen-secreting cells. Under stress conditions, Hsp47 expression is upregulated as part of the heat shock/stress response that mitigates cell damage from noxious stimuli such as elevated temperature, heavy metals, and oxidative stress. Under non-stress conditions, Hsp47 functions as a collagen-specific molecular chaperone that facilitates intracellular procollagen polypeptide synthesis, and triple helix assembly in connective tissues. Previously it has been shown that levels of collagen-specific gene expression are significantly altered in ligaments, menisci, and other connective tissues of the rabbit following surgically induced injuries (increased), and during pregnancy (decreased). The present study was undertaken to determine whether expression of mRNA for the Hsp47 collagen-binding stress protein was also influenced in these experimental models. Since no sequence information was available on the rabbit Hsp47 gene, a partial cDNA for rabbit Hsp47 was first isolated and cloned using reverse transcriptase PCR (RT-PCR) with degenerate oligonucleotide primers. Rabbit Hsp47 sequence-specific primers then designed enabled analysis of Hsp47 mRNA expression in rabbit connective tissues using semiquantitative RT-PCR. It was found that Hsp47 expression is affected in a complex, tissue-specific manner by injury and pregnancy. Hsp47 transcript levels were elevated in the medial collateral ligament (MCL) of the rabbit knee following surgical induction of a gap injury. Transection of the anterior cruciate ligament (ACL), which leads to chronic progressive damage to menisci of the rabbit knee joint, was accompanied by an upregulation of Hsp47 expression in the medial and lateral menisci. Hsp47 mRNA levels were depressed during pregnancy in the kidney and ACL of primigravid adolescent rabbits, but were not altered in corneal tissue during pregnancy or in the ACL of skeletally mature multiparous females. The changes in Hsp47 transcript levels within these connective tissues following injury/pregnancy often, but not always, paralleled changes in collagen-specific gene expression.

Matrix metalloproteinase-13 expression in rabbit knee joint connective tissues: influence of maturation and response to injury

The hypothesis of the present work was that expression of matrix metalloproteinase-13 (MMP-13, collagenase-3) would be induced during conditions involving important matrix remodeling such as ligament maturation, scar healing and joint instability. Therefore, MMP-13 expression in the medial collateral ligament (MCL) during the variable situations of tissue maturation and healing was assessed. MMP-13 expression in three intra-articular connective tissues of the knee (i.e. articular cartilage, menisci and synovium) following the transection of the anterior cruciate ligament of the knee was evaluated at 3 and 8 weeks post-injury. MMP-13 mRNA (semi-quantitative RT-PCR) and protein (immunohistochemistry and Western blotting) were detected in all of the tissues studied. Significantly higher MCL mRNA levels for MMP-13 were detected during the early phases of tissue maturation (i.e. 29 days in utero and 2-month-old rabbits) compared to later phases (5- and 12-month-old rabbits). This pattern of expression was recapitulated following MCL injury, with very high levels of expression in scar tissue at 3 weeks post-injury and then a decline to levels not significantly different from control values by 14 weeks. Elevated mRNA levels correlated with increased protein levels for MMP-13 in both menisci and synovium following the transection of the anterior cruciate ligament and during medial collateral ligament healing. These results indicate that MMP-13 expression is regulated by a number of variables and that high levels of expression occur in situations when connective tissue remodeling is very active.

Pregnancy affects cellular activity, but not tissue mechanical properties, in the healing rabbit medial collateral ligament

Recently, evidence has been accumulating that ligament and joint laxity is altered in women and rabbits during pregnancy. Furthermore, many female adolescents injure ligaments through participation in athletics and other activities. Therefore, to determine whether pregnancy has different effects on the injured and uninjured medial collateral ligament of the rabbit knee, we investigated cellular changes (mRNA levels) and alterations in tissue properties (biomechanics) accompanying pregnancy in animals with the medial collateral ligament injured during adolescence and bred for their primigravid pregnancy as young adults. Assessment of mRNA levels for matrix molecules, matrix metalloproteinases and tissue inhibitor of metalloproteinase-1, growth factors and sex hormone receptors, inflammatory cytokines, inducible nitric oxide synthase, and cyclooxygenase-2 by semiquantitative reverse transcription-polymerase chain reaction revealed that pregnancy had different impacts on scar and uninjured tissue for six of 15 genes assessed. A pregnancy-associated increase in laxity of the medial collateral ligament was observed for rabbits in the uninjured primigravida group; however, no increase was observed for injured rabbits during pregnancy. The injured ligament was already significantly more lax than the normal counterpart, and pregnancy did not lead to additional laxity or prevent the normal decline in laxity as the scar matured in nonpregnant animals. These results indicate that the impact of pregnancy on laxity and cell activity of the medial collateral ligament is dependent on whether the ligament is uninjured or injured. Pregnancy had no significant effect on structural (stiffness and failure load), material (stress at failure and Young's modulus), or viscoelastic (cyclic and static relaxation) properties of tissue from uninjured or injured medial collateral ligament. Therefore, the properties of the healing ligament were not adversely affected during pregnancy in this experimental model. However, it remains to be determined if these results with an injured medial collateral ligament can be extrapolated to the injured anterior cruciate ligament.

Heterogenous response of knee cartilage to pregnancy in the rabbit: assessment of specific mRNA levels

OBJECTIVE

The purpose of this study was to evaluate the effect of pregnancy on mRNA levels for several relevant molecules between five articular cartilage surfaces of the rabbit knee joint.

DESIGN

Total RNA was extracted from the following five knee joint articular surfaces: the lateral and medial femoral condyles (LFC and MFC); the lateral and medial tibial plateau (LTP and MTP); and the femoral groove (G) from pregnant and age-matched non-pregnant skeletally immature New Zealand White rabbits. The RNA was analysed by the sensitive molecular technique of semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) using rabbit specific primer sets. Two types of comparisons were performed: (i) comparison of mRNA levels between cartilage surfaces and (ii) comparison of mRNA levels between pregnant and non-pregnant rabbits within the same articular surfaces.

RESULTS

(i) Total RNA yield from the MFC and G represented 53 and 58% of the total RNA amount from the five cartilage surfaces in both non-pregnant and pregnant rabbits, respectively. Transcript levels for progesterone receptor (PR), aggrecan and biglycan were similar in all of the cartilage surfaces. In contrast, the cartilage surfaces exhibited significantly different transcript levels with a similar pattern for the estrogen receptor (ER), collagenase and urokinase (i.e., MTP<LTP<MFC=G<LFC). In addition, mRNA levels were significantly different for type II collagen (COL 2) between the LFC and MTP, for decorin between the LTP and both LFC and G, for TIMP-1 between the MFC and both the LTP and the G, as well as for PAI-1 between the LTP and MTP. (ii) Total RNA concentration from pregnant animals were significantly decreased in the MFC and the G. For all molecules studied except PR, there was a general tendency for decreased mRNA levels during pregnancy. Compared to non-pregnant rabbits, mRNA levels were significantly decreased in pregnant rabbits for ER in the LFC, LTP and MTP; for COL2 in both LTP and MTP; for aggrecan in the MTP, for biglycan in both LTP and MTP, for decorin in the MTP and G; for collagenase in the LFC, LTP, MTP and G, for urokinase in the LFC, MFC and LTP; for TIMP-1 in the MFC, LTP and MTP. In contrast, PAI-1 exhibited increased mRNA levels during pregnancy in the LFC and LTP. (iii) Comparison of results between the present and the previous study demonstrates that subtle changes in one or more of the cartilage surfaces may be obscured if cartilage is pooled.

CONCLUSION

The present study demonstrates that regulation of RNA levels in articular cartilage during pregnancy is complex and variable between cartilage surfaces.

Gene expression in rabbit menisci during pregnancy

Recent studies have indicated that pregnancy can affect cellular activity in connective tissues such as cartilage, ligaments, and tendons. However, the impact of pregnancy on cellular activity in the menisci, a critical component in joint function, has not been reported. Therefore,the purpose of this study was to evaluate mRNA levels for several relevant molecules in both medial and lateral menisci from the knees of first-time pregnant immature rabbits (primigravida), third-time pregnant mature rabbits (multiparous), and nonpregnant rabbits (age-matched immature and mature controls) by the sensitive molecular technique of semiquantitative reverse transcription--polymerase chain reaction. Total RNA yields from the medial meniscus of multiparous rabbits were reduced to 66% of age-matched control values; however, yields from medial and lateral menisci from primigravida animals or the lateral meniscus of multiparous animals were not significantly depressed. DNA yields were not affected by pregnancy. Type I collagen mRNA levels were significantly depressed in both menisci only in primigravida rabbits. Versican mRNA levels were significantly elevated in both menisci only in multiparous rabbits. None of the transcripts for the other matrix molecules assessed were influenced by pregnancy. Collagenase mRNA levels were unaffected by pregnancy, but TIMP-1 mRNA levels were significantly decreased in the medial meniscus of primigravida rabbits and in the lateral meniscus of multiparous rabbits. Complex changes in the pattern of mRNA expression were observed for growth factors (TGF-beta bFGF, and IGF2). Inducible nitric oxide synthase mRNA expression was not altered during pregnancy. Transcripts for cyclooxygenase-2 were 61 and 50% of control values in the medial meniscus of primigravida and multiparous animals, respectively, while cyclooxygenase-2 mRNA levels were 150 and 188% of control values in the lateral meniscus from primigravida and multiparous animals, respectively. Such results indicate that pregnancy-induced changes in the pattern of mRNA expression are meniscus specific. Furthermore, the results support the hypothesis that different connective tissues of the knee respond to pregnancy in a unique manner.

Gene expression in menisci from the knees of skeletally immature and mature female rabbits

This study, using the sensitive molecular technique of semiquantitative reverse transcription-polymerase chain reaction, evaluated mRNA levels for several molecules in medial and lateral menisci from the knees of skeletally mature and immature rabbits. Total RNA was extracted from the medial and lateral menisci of New Zealand White rabbits with the TRIspin method. Total RNA and DNA were similar in the two menisci of both immature and mature rabbits. The total RNA was reverse-transcribed and analyzed by semiquantitative polymerase chain reaction using rabbit-specific primer sets; levels of mRNA for a subset of molecules differed between the medial and lateral menisci. These variations in mRNA levels were also influenced by the degree of skeletal maturity of the rabbits. For most of the genes, mRNA levels were generally higher in the medial than in the lateral meniscus. The medial meniscus from immature and mature rabbits had significantly increased levels of mRNA for molecules such as transforming growth factor-beta, cyclooxygenase-2, and tissue inhibitor of metalloprotease-1. In contrast, compared with mRNA in the lateral meniscus, that for types II and III collagen, biglycan, insulin-like growth factor-2, plasminogen activator inhibitor-1, and matrix metalloprotease-1 was significantly increased in the medial meniscus of mature rabbits only and that for versican and type-I collagen was significantly increased in the medial meniscus of immature rabbits only. Levels of mRNA for inducible nitric oxide synthase and basic fibroblast growth factor were similar in both menisci for both age groups. The present study demonstrates that regulation of mRNA levels in medial and lateral menisci is tissue-specific and influenced by the skeletal maturity of the animals.

Pregnancy alters gene expression in normal synovium: influence of age and parity

OBJECTIVE

To determine whether pregnancy leads to changes in mRNA levels for molecules in normal synovium in an experimental model.

METHODS

Total RNA was isolated from synovium of primigravida adolescent and skeletally mature rabbits, multiparous adult rabbits, and age matched controls. mRNA levels for cytokines, COX-2, iNOS, growth factors, proteinases and inhibitors, and matrix molecules were assessed by semiquantitative reverse transcription polymerase chain reaction.

RESULTS

Pregnancy led to significant alterations in mRNA levels for 14/17, 6/17, and 5/17 genes in the 3 pregnant groups, respectively, compared to their controls. The only mRNA levels significantly depressed in all 3 groups were for collagen I and III, a finding consistent with a role for relaxin in the observed changes.

CONCLUSION

Pregnancy can affect the molecular biology of the normal synovium and thus pregnancy associated hormones such as relaxin may also affect the inflamed synovium. The effect of relaxin in models of rheumatoid arthritis should be evaluated.

Gender and pregnancy affect neuropeptide responses of the rabbit Achilles tendon

Tendons such as the Achilles tendon are complex structures that are hypocellular, hypovascular, and hyponeural. The development of pathophysiologic function in this tendon because of overuse is relatively common; however, the mechanisms responsible for the development of paratenonitis and tendinosis remain primarily undefined. To understand better a possible regulatory role for neuropeptides (substance P and calcitonin gene related peptide) known to be present in this tissue, the influence of substance P and calcitonin gene related peptide on messenger ribonucleic acid levels for numerous inflammatory molecules, growth factors, and proteinases and inhibitors have been assessed using a semiquantitative reverse transcription-polymerase chain reaction method and explants of paratenon and Achilles tendon midsubstance tissue from adolescent male and female rabbits and tissue from primigravida females. Most of the significant (p < 0.01) changes observed were at the level of the growth factor transcripts and transcripts for proteinases and inhibitors. Twenty-one significant differences in the responsiveness between tissues from male and female rabbits were observed, and 12 significant differences in responsiveness between virgin females and primigravida rabbits were seen. Differences between paratenon and midsubstance responsiveness to the neuropeptides also were observed within each group of animals. The midsubstance tissue from pregnant animals was hyporesponsive to both neuropeptides. These results indicate that neurotransmitter responsiveness of Achilles tendon tissue differs in a gender specific manner and is influenced by pregnancy associated factors.

Temporal alterations in mRNA levels for proteinases and inhibitors and their potential regulators in the healing medial collateral ligament

Wound healing in ligaments is a complex process which leads to functionally impaired scar tissue, even after extended time postinjury. To investigate the potential role of proteinases and inhibitors, as well as potential regulators of their expression, mRNA levels for collagenase, stromelysin, urokinase, PAI-1, and TIMPs 1 to 4 have been assessed by semiquantitative RT-PCR in RNA isolated from rabbit ligaments 3, 6, and 14 weeks postinjury. In addition, mRNA levels for IL-1, TNF, COX-2, and iNOS, potential regulators of proteinase/inhibitor expression, have been assessed. mRNA levels for the proteinases TIMP-1, -2, and -3 and PAI-1 were elevated early in scar tissue, but TIMP-4 mRNA levels exhibited a different pattern. In contrast, mRNA levels for the cytokines iNOS and COX-2 were either unchanged or depressed early after injury. The results indicate that alterations in mRNA levels for proteinases and inhibitors occurring early after injury are likely being influenced by factors other than IL-1, TNF, or products of COX-2 or iNOS.

Pregnancy alters the in vitro responsiveness of the rabbit medial collateral ligament to neuropeptides: effect on mRNA levels for growth factors, cytokines, iNOS, COX-2, metalloproteinases and TIMPs

Explants of tissue derived from the medial collateral ligament (MCL) of normal and pregnant NZW rabbits cultured in the presence of substance P (SP), calcitonin gene-related peptide (CGRP), or both neuropeptides were found to have altered mRNA levels for a number of relevant molecules. Using a very efficient RNA isolation method, semi-quantitative RT-PCR and rabbit-specific primers, mRNA for growth factors (TGFbeta, bFGF, IGF-2, ET-1), cytokines (IL-1, TNF), enzymes (COX-2, iNOS), metalloproteinases (collagenase, stromelysin) and metalloproteinase inhibitors (TIMP-1, TIMP-2) were assessed after culture with or without neuropeptide. The results indicate that SP was effective in lowering mRNA levels for all of the molecules assessed in RNA from normal ligaments except IL-1beta, IGF-2 and TIMP-1, for which there was no significant effect. Similarly, CGRP was effective in lowering mRNA levels for all molecules except TNF, ET-1 and the TIMPs. The extent of the lowering of mRNA levels was both molecule-specific and neuropeptide-specific. When the experiments were repeated with ligament tissue from pregnant animals, a very different pattern of responsiveness to the neuropeptides was observed. While mRNA levels for 9/12 genes assessed were significantly affected by SP when normal MCL tissue was investigated, pregnancy abolished all significant responsiveness to this neuropeptide except for iNOS mRNA levels. In the case of iNOS mRNA, SP induced an increase in the steady-state levels, the opposite to what was observed with tissue from non-pregnant animals. For CGRP and SP+CGRP, tissue from pregnant animals was still responsive, but the pattern of responsiveness was changed from strictly a lowering of steady-state mRNA levels to elevations in mRNA levels for a number of genes. These findings indicate that mRNA levels for a number of genes can be influenced by neuropeptides known to be in ligaments. Thus, neuropeptides likely are important regulators of ligament cell metabolism. As the responsiveness to SP was nearly completely abolished during pregnancy, neuroregulatory influences mediated by this peptide are altered in the pregnant female. This loss of responsiveness to SP may also be one aspect of the analgesia associated with pregnancy.

Altered levels of extracellular matrix molecule mRNA in healing rabbit ligaments

RT-PCR methods were used to amplify, semi-quantify, clone and sequence cDNA fragments specific for rabbit extracellular matrix molecules biglycan, collagen I, collagen III, decorin, lumican, versican, fibromodulin, and also glyceraldehyde-3-phosphate dehydrogenase (G3PDH), using RNA isolated from rabbit ligaments. Sequence analysis of two independent clones of PCR products was used to verify the identity of the cDNA. Semi-quantitative RT-PCR was used to study mRNA levels for these matrix molecules in normal and healing rabbit ligament at three, six, and fourteen weeks post-injury. The yield of RNA from the ligament scar was increased at three and six weeks post-injury, but it had returned to near normal levels by fourteen weeks. On a microgram RNA basis, it was demonstrated that biglycan, collagen I, collagen III and lumican mRNA levels are significantly elevated, versican mRNA levels significantly depressed, and decorin and fibromodulin mRNA levels showed no significant change in response to tissue injury in the ligament during the course of healing. These findings suggest that differential regulation of mRNA levels for these extracellular matrix molecules occurs during ligament healing.

Influence of pregnancy on gene expression in rabbit articular cartilage

OBJECTIVE

Articular cartilage is known to be influenced by estrogen and the pregnancy-associated hormone, relaxin, in vitro. Such observations have raised the possibility that articular cartilage in females may be subjected to unique regulatory influences by such hormones in vivo. The purpose of this study was to evaluate mRNA levels for several relevant molecules in the articular cartilage of pregnant and non-pregnant rabbits.

DESIGN

Total RNA was extracted from New Zealand White rabbit knee articular cartilage using the TRIspin method. The total RNA was reverse transcribed and analysed by the sensitive molecular technique of semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) using rabbit specific primer sets.

RESULTS

Total RNA yield from articular cartilage from primigravida rabbits was reduced to 65% of age-matched control values (P = 0.0003); however the yield from multiparous animals was not significantly depressed. In both cases, DNA yields were not affected by pregnancy. There was a general tendency for depressed mRNA levels for most genes investigated in cartilage from pregnant animals. Articular cartilage from multiparous rabbits showed a significant decrease in mRNA levels for relevant molecules such as type II collagen, biglycan, collagenase and tissue inhibitors of metalloproteinases (TIMP)-1, as well as necrosis factor-alpha (TNF-alpha), inducible nitric oxide synthase (iNOS) and cyclo-oxygenase 2 (COX-2). Transcripts for collagenase and lumican were significantly lower in cartilage from primigravida rabbits. Transforming growth factor beta 1 (TGF-beta 1) transcript levels were significantly decreased in both pregnant groups. In contrast, basic fibroblast growth factor (bFGF) and insulin-like growth factor-2 (IGF-2) mRNA levels were significantly decreased in cartilage from primigravida rabbits, whereas transcripts for these molecules were upregulated in the cartilage of multiparous rabbits.

CONCLUSIONS

The present study demonstrates that regulation of RNA levels in articular cartilage during pregnancy is complex and is influenced by the parity and/or the skeletal maturity of the animals.

Gender and neurogenic variables in tendon biology and repetitive motion disorders

The incidence of repetitive motion disorders is increasing. Numerous studies have indicated that the incidence in females exceeds that in males. Some of the evidence regarding gender related factors in tendon biology is discussed and new data related to the regulation of gene expression in an animal model of tendon overuse, the determination of sex hormone receptors in tendons, and the influence of pregnancy associated factors on gene expression in four different tendons is provided. Furthermore, because neurogenic mechanisms may contribute to inflammatory conditions, new evidence is provided that supports the concept that neurotransmitters can influence expression of genes that could participate in such inflammation. By increasing our understanding of the regulation of tendon cellular and molecular biology, new approaches to preventing disease development and treatment of existing disease may evolve.

Complex alterations in gene expression occur in the knee ligaments of the skeletally mature multiparous rabbit during pregnancy

Pregnancy is known to influence the function of ligaments of the knee in both humans and rabbits. During pregnancy, ligament laxity increases. The mechanism by which these changes in ligament function occur is unknown. The present study was undertaken to assess changes in the pattern of gene expression for a number of molecules which could be involved in the alterations in tissue function. Using RNA isolated from pregnant and age-matched nonpregnant rabbits, levels of mRNA for matrix molecules, proteinases and inhibitors, cytokines and growth factors and inducible nitric oxide synthase were assessed by semi-quantitative RT-PCR. The results indicate that the pregnancy-induced changes in the pattern of gene expression is very complex and differences in the changes observed for the medial collateral ligament and the anterior cruciate ligament may also indicate that ligament-specific effects of pregnancy occur. mRNA levels of some molecules were significantly elevated or suppressed, while others were unchanged, indicating that the changes observed were specific rather than general. While the extent of the molecules assessed was designed to be representative rather than exhaustive, the results indicate that there is likely no simple cause and effect relationship between the observed mechanical alterations during pregnancy and alterations in gene expression in the affected ligaments.

Pregnancy induces complex changes in the the pattern of mRNA expression in knee ligaments of the adolescent rabbit

Knee laxity has been shown to increase during human pregnancy, and the laxity of the rabbit medial collateral ligament also increases during pregnancy. To determine whether the changes in tissue function could be related to alterations in the regulation of gene expression for a subset of relevant molecules in ligaments, RNA was isolated from the medial collateral(MCL) and anterior cruciate(ACL) ligaments of first time pregnant adolescent rabbits. Levels of mRNA for matrix molecules (collagen types I and III and the proteoglycans biglycan, decorin, versican and lumican), proteinases and inhibitors (collagenase, urokinase, PAI-1 and TIMP-1, -2 and -3), growth factors (bFGF, IGF-I, TGF-beta1 and ET-1), cytokines (IL-1beta and TNF) and enzymes responsible for important tissue mediators (COX-2 and iNOS) were assessed by semi-quantitative RT-PCR. In the MCL, levels of transcripts for all of the matrix molecules, growth factors and TIMPs 1 and 2 were significantly depressed at 29 days of pregnancy compared to age-matched non-pregnant controls. In contrast, transcripts for PAI-1 were elevated during pregnancy, while those for collagenase (MMP-1), urokinase, TIMP-3, IL-1beta, TNF, COX-2 and iNOS were not statistically altered. mRNA transcript levels rebounded by 7 days post-partum for most genes studied, indicating that the changes were rapidly reversible. For some molecules, transcript levels were again depressed at 18 days post-partum, indicating that regulatory mechanisms were still not stabilized. Analysis of mRNA from the ACL also revealed changes in the pattern of gene expression, with some similarities and differences from the MCL noted. These results indicate that pregnancy induces reversible changes in mRNA for matrix molecules in ligaments, but differences in responsiveness exist between different ligaments. The complexity of the changes observed indicates that there is probably no simple cause and effect relationship between laxity changes and the molecular alterations during pregnancy.

Postmortem stability of total RNA isolated from rabbit ligament, tendon and cartilage

The stability of RNA, particularly mRNA, in tissues is under complex regulation. Most studies to date have focused on very cellular tissues and not connective tissues such as ligaments, tendons and cartilage. As the availability of such tissues for transplantation or research purposes is frequently delayed following death, it is important to determine whether RNA stability in such tissues is influenced by time postmortem. To approach this question, skeletally mature NZW rabbits were used to investigate RNA integrity over time in dense, hypocellular connective tissues and in several hypercellular organ tissues such as brain, kidney, liver and lung. Samples were analyzed at varying intervals postmortem with respect to rRNA integrity by agarose gel electrophoresis and ethidium bromide staining and mRNA integrity by Northern blot analysis and RT-PCR. No degradation of rRNA or loss in integrity of mRNA for genes of low and high copy number was observed up to 96 h postmortem. These findings confirm that it is likely appropriate to use properly stored postmortem dense connective tissues for molecular biological investigations.

Staphylococcus aureus strains differ in their in vitro responsiveness to human urokinase: evidence that methicillin-resistant strains are predominately nonresponsive to the growth-enhancing effects of urokinase

Clinical isolates of Staphylococcus aureus were found to exhibit strain-specific heterogeneity to the growth-enhancing effects of human urokinase (UK), a proteinase with plasminogen activator activity. Nine out of fourteen (64%) methicillin-sensitive strains of S. aureus were responsive to UK in "in vitro" cultures. In contrast, 3/29 (10%) methicillin-resistant strains were responsive to the proteinase. When only strains isolated from western Canada were considered, 6/11 methicillin-sensitive strains and 1/26 methicillin-resistant strains were responsive to UK. The single western Canadian methicillin-resistant strain (strain 456) responsive to UK was one of two isolated from the same patient, indicating that the two strains were phenotypically different. Strain 456, resistant to 32 micrograms methicillin/mL, was responsive to as little as 50 U UK/mL and enhancement of growth was evident by 9 h of incubation at 37 degrees C. This growth enhancement was specific to UK and not duplicated by equivalent concentrations of other proteins (bovine serum albumin, trypsin, plasminogen). The results presented indicate differences in the frequency of the UK-responsive phenotype between methicillin-sensitive and -resistant S. aureus. These findings indicate that the UK phenotype of S. aureus may have utility in both phenotyping clinical isolates, as well as providing insights into the regulation of growth in this clinically important organism.

Transcatheter laser dissolution of human atherosclerotic plaques: a model for testing catheters and techniques

We constructed a model of the human arterial circulation that can be used to test laser angioplasty catheters and techniques on obstructed human coronary arteries under simulated physiologic conditions of blood pressure and flow. In this model system, a balloon-tipped catheter with a central, 0.02-cm light fiber was used to deliver 4 W of laser energy to two obstructed human cadaver coronary artery segments and four normal dog femoral artery segments. Flushing the catheter with saline during the lases minimized lateral thermal tissue damage. Channels were created in the obstructed arteries that were twice the diameter of the light fiber used to lase. One of four dog arteries perforated, underscoring the potential hazards of the procedure and the need for laser catheters that are flexible and capable of precise alignment.