Changes in diet and physical activity in the 1990s in a large British sample (1958 birth cohort)

OBJECTIVES

To investigate whether adults studied in 1991 and 1999 (at ages 33 and 42 y) improved their diet and their physical activity level, in the direction of recommendations issued during the same period.

DESIGN

Longitudinal 1958 British birth cohort study.

SETTING

England, Scotland and Wales.

PARTICIPANTS

All births, 3rd-9th March, 1958. A minimum of 11 341 participants provided data at 33 y, 11 361 at 42 y.

MAIN OUTCOME MEASURES

Frequency of leisure time activity and consumption of (i) fried food, (ii) chips, (iii) wholemeal bread and (iv) fruit and salad/raw vegetables, at 33 and 42 y.

RESULTS

Most people changed their physical activity and dietary habits over the 8-y period. About a third of men and women increased, and a third decreased their activity frequency. Findings for fried food consumption were similar. A significantly greater proportion of cohort members decreased their chips consumption (32%), rather than increased it (17%) and increased their fruit and salad consumption (30%), rather than decreased it (25%). In all, 26% of men and 33% of women consistently ate, or switched to eating mostly wholemeal bread, while 56% of men and 48% of women consistently ate less or switched to eating less. Social gradients were seen for activity and diet in 1991, but associations between social factors or body mass index and change in activity or diet were inconsistent.

CONCLUSIONS

Lifestyle habits such as dietary intake and physical activity are slow to change. Current health promotion strategies may need to be supplemented with additional methods to affect the desired change in these habits.

Factors contributing to failure of laparoscopic Nissen fundoplication and the predictive value of preoperative assessment

BACKGROUND

Laparoscopic Nissen fundoplication (LNF) has established itself as the procedure of choice in the surgical management of the majority of patients suffering from gastroesophageal reflux disease (GERD). There are, however, few available data on the assessment of long-term failures after LNF.

METHODS

We sought to clarify the mechanisms of failure among a group of patients who reported suboptimal results after LNF. In addition, we attempted to identify specific elements in the preoperative evaluation of GERD patients that might herald a predisposition to anatomical or physiological failure.

RESULTS

One hundred and thirty-one consecutive patients who underwent LNF by a single surgeon were analyzed to identify reasons for surgical failure. Fourteen patients (10.6%) comprised the failure group. Detailed independent statistical analysis identified a hiatus hernia greater than 3 cm at operation (P = 0.003), abnormal preoperative pH analysis in the upright position (P = 0.039), failure to respond to proton pump inhibition preoperatively (P = 0.015), and a preoperative psychiatric history (P = 0.0012) as predictors of subsequent failure.

CONCLUSIONS

In patients who do not respond to proton pump inhibition preoperatively, the evaluating surgeon should be circumspect in advocating antireflux surgery. A detailed assessment of underlying psychiatric or psychological symptoms must also be made. If a large (>3 cm approximately) hiatus hernia is identified or there is abnormal pH analysis in the upright position preoperatively, the surgeon should be guarded about the long-term outcome, and patients should be advised accordingly.

N-acetylcysteine attenuates lung injury in a rodent model of fracture

BACKGROUND

Neutrophil-mediated lung injury is a cause of significant morbidity and mortality in patients with multiple injuries. We have shown previously that fracture hematoma can activate neutrophils and is thus a putative mediator of the systemic inflammatory response syndrome (SIRS), acute respiratory distress syndrome (ARDS) and multiple organ failure (MOF) in those patients with severe skeletal trauma. Our aim was to establish a rodent model of fracture which caused lung injury and subsequently to administer a drug following fracture to attenuate the lung injury. The drug we chose was N-acetylcysteine, a potent antioxidant.

ANIMALS AND METHODS

Adult Sprague-Dawley rats were assigned to 4 groups: (1) general anesthetic only, (2) general anesthetic with bilateral femur fractures and nailing, (3) general anesthetic and N-acetylcysteine, (4) general anesthetic with bilateral femur fractures and nailing and N-acetylcysteine after the injury (n = 6 in each group). The dose of N-acetylcysteine was 0.5 mg/kg which was given intraperitoneally after injury to the treated groups. The rats were killed 24 hours after injury and some parameters of lung injury were evaluated--i.e., bronchoalveolar lavage (BAL), lung tissue myeloperoxidase levels (MPO) and wet/dry ratios of lung tissue. The results were analyzed, using one-way analysis of variance.

RESULTS

Bilateral femur fracture produced a significant lung injury, measured by increases in MPO (25-43 microg/g tissue) and BAL protein (460-605 microg/mL). This effect was attenuated by treatment with N-acetylcysteine (MPO 43-9 microg/mL, BAL protein 605-198 microg/mL).

INTERPRETATION

N-acetyl cysteine, if given after skeletal trauma, is of potential therapeutic benefit, in preventing SIRS, ARDS and MOF.

Combination of low birth weight and high adult body mass index: at what age is it established and what are its determinants?

OBJECTIVE

To investigate growth trajectories and predictive factors for those with low birth weight and high adult BMI.

DESIGN

Birth cohort study.

SETTING

England, Scotland, and Wales.

PARTICIPANTS

All born 3-9 March, 1958.

MAIN OUTCOME MEASURES

People at "high risk" of adult disease were defined as having a combination of lower birth weight (in the lowest third of the distribution) and high BMI (in the highest third of the distribution at age 33).

RESULTS

284 of 3462 men and 338 of 3555 women were identified as "high risk". This group was shorter than other cohort members at age 7, on average by 1.2 cm (boys) and 1.8 cm (girls), with a deficit of about 3 cm in adult height. The "high risk" group had a similar mean weight to other subjects at age 7, but were heavier thereafter through to age 23. BMI was increased at all ages in the "high risk" group. Independent predictors include paternal BMI, maternal height and smoking in pregnancy, and social class. For each SD increase in father's BMI the odds of low birth weight/high BMI increased by about 20%. For maternal height, a 1 cm increase reduced the odds of low birth weight/high BMI by about 5%. Increased ORs for "high risk" were found for those with manual social origins (1.61 for men; 1.49 for women) and for maternal smoking in pregnancy (1.79 and 2.27 respectively).

CONCLUSIONS

Maternal short stature, low social class, and smoking during pregnancy influence the development of "high risk" for adult chronic disease. The causes of high risk therefore seem to reside in utero and even earlier, in the mother's lifetime, with adverse conditions having a detrimental affect and favourable conditions protecting against high risk.

Cigarette consumption and socio-economic circumstances in adolescence as predictors of adult smoking

AIM

To investigate effects of cigarette consumption level and socio-economic circumstances during adolescence on adult smoking.

METHODS

1958 British birth cohort (all births 3-9 March 1958). Logistic regression used to predict (i) smoking at 41 years and (ii) persistent smoking (at 23, 33 and 41 years) from cigarette consumption and socio-economic circumstances at 16 years, indicated by social class and educational qualifications.

RESULTS

Of 6537 subjects with full smoking history, 30% smoked at 16 years, 23% smoked at 41 years and 19% smoked at 23, 33 and 41 years (persistent smokers). Heavier smokers at 16, 23 and 33 years were more likely to smoke at 41 years than lighter smokers. The odds ratio (OR) of smoking at 41 years was 2.5 for men and 3.0 for women who smoked >/=60 cigarettes/week at age 16, relative to <20 cigarettes/week. Subjects from manual social backgrounds and those with no qualifications had elevated risks of being a smoker at 41 years or a persistent smoker. These effects were robust to adjustment for adolescent consumption level (e.g. adjusted OR for no qualifications was 3.8). However, adolescent consumption level modified the effect of educational achievements. Among lighter adolescent smokers, those gaining higher qualifications had lower prevalence of smoking at 41 years (16%) than men with no qualifications (83%); among heavier adolescent smokers, prevalence was more similar for subjects with higher (56%) and no qualifications (69%).

CONCLUSIONS

Socio-economic background appears to influence adult smoking behaviour separately from adolescent cigarette consumption which is a recognized measure of nicotine dependence. There was some evidence that effects of early nicotine dependence are modified by educational achievements.

Infant feeding and obesity through the lifecourse

In the 1958 British birth cohort (n = 12,857 at age 7), breast feeding and BMI were unrelated in childhood. Breast feeding was protective against increased BMI at ages 16 and 33 years in females, and at 33 years in males, but this effect was markedly reduced and no longer significant after adjustment for confounding factors.

Child to adult socioeconomic conditions and obesity in a national cohort

OBJECTIVE

Critical stages in childhood are suspected for adult obesity. We sought to identify (i) whether risk of adult obesity is influenced by childhood socioeconomic conditions in addition to those in adulthood; and (ii) whether conditions in childhood act independently or through their association with education or parental obesity.

DESIGN

Longitudinal, 1958 British birth cohort.

SUBJECTS

A total of 11 405 men and women followed to age 33 y.

MEASUREMENTS

Social class at birth and ages 7, 11, 16, 23 and 33 y. Obesity (BMI> or =30) at age 33 y.

RESULTS

Social class was related to obesity, cross-sectionally at ages 16 (women), 23 and 33 y, but not at younger ages. In analysis of adult obesity (age 33 y) and social class at five life stages, class at age 7 y significantly predicted obesity for women (adjusted odds ratio (OR)=1.31, that is, the odds increased by 31% for each decrease in social class). For men, class at birth and age 23 y predicted adult obesity (adjusted OR=1.19 and 1.16, respectively). Education was also associated with adult obesity, increasing the odds by 30% (men) and 35% (women) for each decrease in qualification level. Adjustment for education level and parental BMI did not abolish the effect on adult obesity of class at age 7 y among women, nor of class at birth among men, while class at age 23 y reduced to borderline significance.

CONCLUSIONS

Cross-sectional associations for social class and obesity can be misleading and obscure effects of childhood socioeconomic conditions. Influences around birth to age 7 y have a long-lasting impact on the risk of adult obesity.

Social inequalities in low birth weight in England and Wales: trends and implications for future population health

STUDY OBJECTIVE

To examine social inequalities and trends in low birth weight in England and Wales.

DESIGN

Analysis of routine birth data, comparing (a) couple and sole registered births, and (b) manual and non-manual occupational groups.

SETTING

England and Wales, 1993-2000.

MAIN RESULTS

Social inequalities in low birth weight were evident throughout 1993-2000: relative to the non-manual group, there is an increased risk for the manual group (range in RR 1.22-1.35) and sole registrations (RR 1.51-1.67). An estimated 6.5% (2979 births) of low birth weight in 2000 could have been avoided if risks associated with the manual group were absent, and 2.8% (1290 births) avoided if risks associated with sole registration were absent. Between 1993 and 2000, the low birthweight rate increased significantly with an estimated overall increase of 11%. Increases were evident in all social groups (15% in manual, 11% in sole registrations and 9% in non-manual); however relative to non-manual the increase in RRs were not statistically significant for manual or sole registrations. When multiple births are excluded, the rate of low birth weight is reduced but there is still a significant increase over time and social differentials are undiminished.

CONCLUSIONS

There are social inequalities in low birth weight in England and Wales that have not narrowed over an eight year period, 1993-2000. These inequalities are likely to affect childhood and adult health inequalities in the future, hence strategies will need to address differences in low birth weight and further monitoring of trends is therefore desirable.

Predicting outcome after appendicectomy

AIM

To validate an intraoperative appendicitis severity score (IASS) and examine outcome following emergency appendectomy.

METHODS

A prospective study was undertaken, enrolling consecutive patients undergoing emergency appendicectomy. Data were obtained independently on preoperative Alvarado scores, IASS (0-3: 0 no inflammation, 1 engorged appendix/no peritonitis, 2 peritoneal reaction/exudate or 3 evidence of perforation/abscess) and postoperative outcome parameters.

RESULTS

There were 149 patients identified with a mean age of 20.7 years. There was no association between Alvarado score and length of hospital stay, septic complication, patient sex or duration of symptoms (p>0.05). IASS was found to be an independent risk factor for septic complication, wound infection (p<0.05) and length of hospital stay (p<0.001). There was no correlation between preoperative duration of symptoms or time until surgery and intraoperative score.

CONCLUSIONS

This simple scoring system can identify patients more likely to suffer morbidity following emergency appendicectomy. Specifically, this system identifies patients who have a high risk of sepsis and therefore could be of use when comparing healthcare performance.

Cutting edge: bacterial lipoprotein induces endotoxin-independent tolerance to septic shock

Tolerance to bacterial cell wall components is an adaptive host response. Endotoxin/LPS tolerance is characterized by a survival advantage against subsequent lethal LPS challenge. However, it is uncertain whether LPS tolerance can afford protection against other septic challenges. In this study, we show that tolerance induced by bacterial lipoprotein (BLP) protects mice against not only BLP-induced lethality, but also LPS-, live bacteria-, and polymicrobial sepsis-induced lethality. In contrast, LPS tolerance offers no survival benefit against the latter two challenges. Furthermore, induction of BLP tolerance results in overexpression of complement receptor type 3 and FcgammaIII/IIR on neutrophils (polymorphonuclear neutrophils) and peritoneal macrophages, with increased bacterial recognition and bactericidal activity, whereas LPS-tolerized mice exhibit an impaired ability to ingest and to kill bacteria. These results indicate that BLP tolerance is a novel adaptive host response associated with a unique protective effect during septic shock.

Macrophages that have ingested apoptotic neutrophils release tissue inhibitor of matrix metalloproteinase 1

Background

Apoptosis of neutrophils (PMNs) in vivo is followed by their rapid uptake into adjacent phagocytic cells, a critical process in tissue remodelling, regulation of the immune response and resolution of inflammation. Tissue inhibitor of matrix metalloproteinase (TIMP) 1 is crucial in regulating the matrix-degrading properties of matrix metalloproteinases released by activated PMNs in inflammatory foci. The aim was to elucidate whether mononuclear-derived phagocytes (MDPs) release TIMP-1 and/or MMP-9 after phagocytosis of apoptotic PMNs.

Methods

MDPs were prepared from peripheral blood monocytes after isolation by culture in well plates for 7–10 days. PMNs were isolated from similarly healthy volunteers. PMN apoptosis was induced by 10 min of ultraviolet irradiation at 254 nm. After a further 6 h of incubation apoptosis was assessed and was routinely greater than 50 per cent. Apoptotic PMNs were then added to MDPs in specific ratios. After 1 h non-phagocytosed PMNs were washed away. RPMI was added to MDPs in well plates and 18 h later the supernatant was collected. Phagocytosis of opsonized zymosan, exposure to tumour necrosis factor (TNF) α and lipopolysaccharide (LPS), and finally MDPs alone were used as controls. TIMP-1 was quantified by enzyme-linked immunosorbent assay.

Results

TIMP-1 was released by MDPs after phagocytosis of apoptotic PMNs and opsonized zymosan. MDPs also produced TIMP-1 after stimulation with TNF-α–LPS. Levels of TIMP-1 from these MDPs were significantly different from those in MDPs alone.

Conclusion

Phagocytosis of apoptotic PMNs is an integral part of the host's attempt to resolve inflammation in altered immune states such as the systemic inflammatory response syndrome in which PMNs persistently release proinflammatory substances damaging the local microenvironment. This study has demonstrated that MDPs release TIMP-1 after phagocytosis of apoptotic PMNs and that this may play a role in the regulation of tissue remodelling and repair in response to inflammation.

Bacterial lipoprotein delays neutrophil apoptosis via a CD14-independent pathway

Background

Lipopolysaccharide (LPS) is considered the most potent exogenous mediator of the systemic inflammatory response syndrome (SIRS) which results, in part, from delayed neutrophil (PMN) apoptosis. The effects of another ubiquitous bacterial component, bacterial lipoprotein (BLP), the most abundant protein in the cell wall of all bacteria, on PMN apoptosis are unknown. The potential role of BLP in the regulation of PMN apoptosis was investigated and these effects were compared with those of LPS.

Methods

PMNs from healthy volunteers were isolated and exposed to identical concentrations of LPS and BLP in the presence or absence of recombinant antihuman CD14 monoclonal antibody. PMN apoptosis was assessed 6 hourly using Annexin V–propidium iodide staining and confirmed on cell morphology. PNM activation was assessed flow cytometrically using expression of functional markers CD11b and CD18.

Results

BLP significantly delayed PMN apoptosis and upregulated PMN adhesion receptor expression compared with control values. The effects seen were markedly similar to those of LPS.

Conclusion

BLP is capable of upregulating PMN adhesion receptor expression and delaying PMN apoptosis in a time- and dose-dependent manner independent of CD14. The potency, and the effects mediated by, BLP are very similar to those of LPS. This identifies BLP as a putative mediator of SIRS and demands that due attention be paid to other bacterial products in the investigation and treatment of septic states.

Childhood and adulthood risk factors for socio-economic differentials in psychological distress: evidence from the 1958 British birth cohort

Social inequalities in psychological status have been attributed to health selection and to social causation. We used data from the 1958 British birth cohort, followed over three decades, to identify causes of inequality in adulthood. Psychological status prior to labour market entry influenced inter-generational mobility, but selection effects were weaker for intra-generational mobility, between age 23 and 33. However, selection failed to account for social differences in risk of distress of approximately threefold in classes IV&V compared with I&II. Both childhood and adult life factors appeared to contribute to the development of inequalities. The principal childhood factors were ability at age 7 for both sexes and adverse environment (institutional care for men and low class for women). Adult life factors varied, with stronger effects for work factors (job strain and insecurity) for men and qualifications on leaving school, early child-bearing and financial hardship for women. Gradients in psychological distress reflect the cumulative effect of multiple adversities experienced from childhood.

Unemployment and obesity among young adults in a northern Finland 1966 birth cohort

OBJECTIVE

To establish (1) if obesity in adolescence predicts a long history of unemployment and other adverse social outcomes at age 31 y and, conversely, (2) the effect of a long history of unemployment on the risk of obesity at 31 y.

DESIGN AND SUBJECTS

A longitudinal, population-based study of 9,754 subjects born in 1966 in Northern Finland was conducted. The cohort members were studied at birth, 1, 14 and 31 y.

MEASUREMENTS

Body mass index (BMI) at 14 and 31 y; work history, as self-reported at 31 y and as recorded in national registers of the total number of days each subject had received unemployment allowance between 1985 and 1997; place of residence at 14 and 31 y; family social class at 14 y; subject's school performance at 16 y; marital status and number of children at 31 y.

RESULTS

Overweight and obesity at 14 y did not predict a long history of unemployment at 31 y, but were associated with a low level of education, and being single or divorced at 31 y among females. A long history of unemployment (register data) was associated with an increased risk of obesity among women, but not men, after controlling for potential confounding factors (social class at 14 y, BMI at 14 y, school performance at 16 y, place of residence, and number of children). The adjusted OR (95% CI) was 1.09 (0.72-1.63) for men, and 1.64 (1.07-2.50) for women.

CONCLUSION

Adverse social outcomes of adolescent obesity seemed to emerge more for women. Subjects with low school performance and women with a long unemployment history are at increased risk of obesity.

Neurovirulence depends on virus input titer in brain in feline immunodeficiency virus infection: evidence for activation of innate immunity and neuronal injury

Lentiruses cause neurological disease depending on the virus strain and its neurotropism, yet it remains uncertain to what the impact of infectious virus quantity in the brain early in infection is on the subsequent development of neurological disease or neurovirulence. We investigated the relationship between infectious virus input titer and the resulting neurovirulence, using ex vivo and in vivo assays of feline immunodeficiency virus (FIV)-induced neurovirulence. FIV infection of cell cultures and neonatal cats was performed using 10(2.5) (low-titer) or 10(4.5) (high-titer) 50% tissue culture infectious doses (TCID(50))/ml of the neurovirulent FIV strain, V1CSF. Ex vivo neurotoxicity assays revealed that conditioned medium (CM) from feline macrophages infected with high-titer (P <.001) or low-titer (P <.01) V1CSF induced greater neuronal death than CM from mock-infected cells. In vivo, animals infected intracranially with high-titer V1CSF showed neurodevelopmental delays compared to mock-infected animals (P <.001) and animals infected with low-titer V1CSF (P <.02), concurrent with reduced weight gains and greater depletion of CD4+ cells over a 12-week period. Neuropathological changes, including astrogliosis, macrophage activation, and neuronal damage, were evident in V1CSF-infected animals and were viral titer dependent. In vivo magnetic resonance (MR) spectroscopy and proton nuclear magnetic resonance ((1)H-NMR) spectroscopy of tissue extracts revealed evidence of neuronal injury, including reduced N-acetyl aspartate/creatine (P <.05) and increased trimethylamine/creatine (P <.05) ratios, in the frontal cortex of high-titer V1CSF-infected animals compared to the other groups. T2-weighted MR imaging detected increased signal intensities in the frontal cortex and white matter of V1CSF-infected animals relative to controls, which was more evident as viral titer increased (P <.01). The present findings indicate that lentivirus infectious titers in the brain during the early stages of infection determine the severity of neurovirulence, reflected by neurobehavioral deficits, together with neuroradiological and neuropathological findings of activation of innate immunity and neuronal injury.

Use of autologous blood as part of the perfusate for cardiopulmonary bypass: a priming technique

In an attempt to replace the oncotic and protein coating capabilities of serum albumin in the perfusate, we established a priming protocol that used autologous blood as part of the perfusate solution. Prior to March 1, 1999, our standard priming protocol was 1650 ml of crystalloid with 250 ml of 5% serum albumin and 5,000 units of heparin. After removing albumin from our prime, our standard protocol was altered to include 40 ml of the patient's autologous blood in 1,800 ml of crystalloid and 10,000 units of heparin. To determine the intraoperative effects of using albumin/crystalloid primes (Group A), autologous blood/crystalloid primes (Group B) and crystalloid primes (Group C), a total of 178 patients were sequentially evaluated. Intraoperative parameters evaluated were total protein (TP), colloid osmotic pressure (COP), platelets (Plts) and fluid requirements during cardiopulmonary bypass (CPB). During an overlapping 12-month period of time, 1,092 consecutive cardiac surgical cases using CPB (584 albumin prime; 508 autologous blood prime) were evaluated for clinical outcomes in terms of mortality and length of hospitalization. In addition, over a period of 15 months, 1,458 patients in both the autologous blood/crystalloid group and the crystalloid only group were evaluated for the incidence of high-pressure excursions (HPE) after going on bypass. Comparative reviews of TP, COP and Plts demonstrated no significant difference 10 min after the start of bypass between Groups A and B. However, in Group C, there was a statistically significant increase in the intraoperative fluid requirements during CPB, compared to both of the other groups. There was no significant difference in the incidence of HPE, with an occurrence of 1.04% in the crystalloid only group and 1.11% in the autologous blood/crystalloid group. Autologous blood perfusates were identical to albumin perfusates in their platelet protection and reduction of fluid shifts during the intraoperative period.

Feline immunodeficiency virus xenoinfection: the role of chemokine receptors and envelope diversity

The use of chemokine receptors as cell recognition signals is a property common to several lentiviruses, including feline, human, and simian immunodeficiency viruses. Previously, two feline immunodeficiency virus (FIV) isolates, V1CSF and Petaluma, were shown to use chemokine receptors in a strain-dependent manner to infect human peripheral blood mononuclear cells (PBMC) (J. Johnston and C. Power, J. Virol. 73:2491-2498, 1999). Since the sequences of these viruses differed primarily in regions of the FIV envelope gene implicated in receptor use and cell tropism, envelope chimeras of V1CSF and Petaluma were constructed to investigate the role of envelope diversity in the profiles of chemokine receptors used by FIV to infect primate cells. By use of a receptor-blocking assay, all viruses were found to infect human and macaque PBMC through a mechanism involving the CXCR4 receptor. However, infection by viruses encoding the V3-to-V5 region of the V1CSF surface unit was also inhibited by blockade of the CCR3 or CCR5 receptor. Similar results were obtained with GHOST cells, human osteosarcoma cells expressing specific combinations of chemokine receptors. CXCR4 was required for infection by all FIV strains, but viruses expressing the V3-to-V5 region of V1CSF required the concurrent presence of either CCR3 or CCR5. In contrast, CXCR4 alone was sufficient to allow infection of GHOST cells by FIV strains possessing the V3-to-V5 region of Petaluma. To assess the role of primate chemokine receptors in productive infection, Crandell feline kidney (CrFK) cells that expressed human CXCR4, CCR3, or CCR5 in addition to feline CXCR4 were generated. Sustained infection by viruses encoding the V3-to-V5 region of V1CSF was detected in CrFK cells expressing human CCR3 or CCR5 but not in cells expressing CXCR4 alone, while all CrFK cell lines were permissive to viruses encoding the V3-to-V5 region of Petaluma. These results indicate that FIV uses chemokine receptors to infect both human and nonhuman primate cells and that the profiles of these receptors are dependent on envelope sequence, and they provide insights into the mechanism by which xenoinfections may occur.

Envelope gene-mediated neurovirulence in feline immunodeficiency virus infection: induction of matrix metalloproteinases and neuronal injury

The release of neurotoxins by activated brain macrophages or microglia is one mechanism proposed to contribute to the development of neurological disease following infection by lentiviruses, including feline immunodeficiency virus (FIV). Since molecular diversity in the lentiviral envelope gene influences the expression of host molecules implicated in neuronal injury, the role of the envelope sequence in FIV neuropathogenesis was investigated by using the neurovirulent FIV strain V1CSF, the nonneurovirulent strain Petaluma, and a chimera (FIVCh) containing the V1CSF envelope gene in a Petaluma background. All three viruses replicated in primary feline macrophages with equal efficiency, but conditioned medium from V1CSF- or FIVCh-infected cells was significantly more neurotoxic than medium from Petaluma-infected cultures (P < 0.001) and could be attenuated in a dose-dependent manner by treatment with either the matrix metalloproteinase (MMP) inhibitor prinomastat (PMT) or function-blocking antibodies to MMP-2. Although FIV sequences were detectable by PCR in brain tissue from neonatal cats infected with each of the viral strains, immunohistochemistry revealed increased astrogliosis and macrophage activation in the brains of V1CSF- and FIVCh-infected cats relative to the other groups, together with elevated markers of neuronal stress that included morphological changes and increased c-fos immunoreactivity. Similarly, MMP-2, but not MMP-9, mRNA and protein expression was increased in brain tissues of V1CSF- and FIVCh-infected cats relative to Petaluma-infected animals (P < 0.01). Infection with V1CSF or FIVCh was also associated with greater CD4(+) cell depletion (P < 0.001) and neurodevelopmental delays (P < 0.005), than in Petaluma-infected animals; these deficits improved following PMT therapy. These findings indicated that diversity in the envelope gene sequence influenced the neurovirulence exhibited by FIV both in vitro and in vivo, possibly through a mechanism involving the differential induction of MMP-2.

Neuroimmune and neurovirological aspects of human immunodeficiency virus infection

Like most lentiviruses, HIV-1 causes both immune suppression and neurological disease. Neurological disease may occur at any stage of HIV infection but is most apparent with severe immune suppression. Cognitive impairment, reflected strikingly by HIV-associated dementia, has attracted intense interest since the outset of the HIV epidemic, and understanding of its pathogenesis has been spurred on by the emergence of several hypotheses outlining potential pathogenic mechanisms. The release of inflammatory molecules by HIV-infected microglia and macrophages and the concurrent neuronal damage play central roles in the conceptualization of HIV neuropathogenesis. Many inflammatory molecules appear to contribute to the pathogenic cascade and their individual roles remain undefined. At the same time, the abundance of virus in the brain and the type or strain of virus found in the brain may also be important codeterminants of neurological disease, as shown for other neurotropic viruses. Coreceptor use by HIV found in the brain appears to closely mirror what has been reported in systemic macrophages. The impact of HAART on viral genotype and phenotype found in the brain, and its relationship to clinical disease, remain uncertain. Several interesting animal models have been developed, using other lentiviruses, transgenic animals, and HIV-infected SCID mice, that may prove useful in future pathogenesis and therapeutic studies. Despite the progress in the understanding of HIV neuropathogenesis, many questions remain unanswered.

Progress in clinical neurosciences: The neuropathogenesis of HIV infection: host-virus interaction and the impact of therapy

Despite the availability of highly active antiretroviral therapy (HAART), primary HIV-related neurological diseases remain major problems in HIV clinics. The present review examines the pathogenesis of HIV-related dementia and the less severe minor cognitive and motor deficit, together with distal sensory and drug-induced toxic polyneuropathies. Abnormal host immune responses within the nervous system and the role of viral expression and diversity are emphasized in relation to neurovirulence. Induction of innate immune responses within the central and peripheral nervous systems, largely mediated by cells of macrophage lineage, appear to be common to the development of primary HIV-related neurological disease. Activation of these cell types results in the release of a cascade of inflammatory molecules including cytokines, chemokines, matrix metalloproteinases, and arachidonic acid metabolites that influence neuronal survival. Individual viral proteins encoded by envelope and tat genes and discrete sequences within these genes influence the extent to which these pro-inflammatory molecules are induced. At the same time, systemic immune suppression may influence the occurrence and severity of HIV-related neurological diseases. Implementation of HAART and neuroprotective treatments improves neurological function although the evolution of drug-resistant viral strains limits the sustained benefits of HAART.