Metalloproteinases in biology and pathology of the nervous system

Matrix metalloproteinases (MMPs) and ADAMs (a disintegrin and metalloproteinase) are part of a larger family of structurally related zinc-dependent metalloproteinases called metzincins. Structurally, MMPs are divided in three domains: an amino-terminal propeptide region, an amino-terminal catalytic domain, and a carboxy-terminal domain that is involved in substrate binding. ADAMs have a prodomain, a metalloprotease region, a disintegrin domain for adhesion, a cysteine-rich region, epidermal-growth-factor repeats, a transmembrane module and a cytoplasmic tail. The activity of MMPs is tightly regulated in several ways: at the level of transcription, by post-translational modifications such as proteolysis, and through the action of endogenous tissue inhibitors of metalloproteinases. The regulation of ADAMs is less well understood, although there is some evidence that the same three levels of regulation might control ADAM activity. MMPs and ADAMs have been implicated in neuroinflammation and multiple sclerosis (MS), in the pathogenesis of malignant gliomas, and in other neurological conditions such as stroke, viral infections and Alzheimer's disease. In the case of ADAMs, their role in these pathological states has begun to be explored, but the available literature is still in its infancy. Although the detrimental roles of metalloproteinases are well documented, some of their functions in the central nervous system (CNS) might be beneficial. For example, some metalloproteinases are expressed in the CNS during development, pointing to a possible role in brain maturation. Similarly, metalloproteinases have been implicated in myelinogenesis and axon growth. Furthermore, metalloproteinases are upregulated after injury to the CNS, indicating a possible relevance to tissue repair. Several challenges remain in the study of metalloproteinases and their role in brain function. It will be necessary to understand the balance between the beneficial and detrimental roles of MMPs to determine whether they can be used as targets for therapeutic intervention. It will also be important to identify the physiological substrates of the different metalloproteinases, and to develop selective antagonists against the various members of the metalloproteinase families; the lack of such tools constitutes one of the main limitations to the growth of the field at present.

Matrix metalloproteinases (MMPs) have been implicated in several diseases of the nervous system. Here we review the evidence that supports this idea and discuss the possible mechanisms of MMP action. We then consider some of the beneficial functions of MMPs during neural development and speculate on their roles in repair after brain injury. We also introduce a family of proteins known as ADAMs (a disintegrin and metalloproteinase), as some of the properties previously ascribed to MMPs are possibly the result of ADAM activity.

Proinflammatory effects of bacterial lipoprotein on human neutrophil activation status, function and cytotoxic potential in vitro

Bacterial lipoprotein (BLP) is the most abundant protein in gram-negative bacterial cell walls, heavily outweighing lipopolysaccharide (LPS). Herein we present findings demonstrating the potent in vitro effects of BLP on neutrophil (PMN) activation status, function, and capacity to transmigrate an endothelial monolayer. PMNs are the principal effectors of the initial host response to injury or infection and constitute a significant threat to invading bacterial pathogens. The systemic inflammatory response syndrome (SIRS) is characterised by significant host tissue injury mediated, in part, by uncontrolled regulation of PMN cytotoxic activity. We found that BLP-activated human PMN as evidenced by increased CD11b/CD18 (Mac-1) expression. Up-regulation of PMN Mac-1 in response to BLP occurred independently of membrane-bound CD14 (mCD14). A similar up-regulation of intercellular adhesion molecule-1 (ICAM-1) on endothelial cells was observed whilst E-Selectin expression was unaffected. PMN transmigration across a human umbilical vein endothelial cell (HUVEC) monolayer was markedly increased after treating either PMN's or HUVEC independently with BLP. This increased transmigration did not occur as a result of any direct effect of BLP on HUVEC monolayer permeability, assessed objectively using the passage of FITC-labeled Dextran-70. BLP primed PMN for enhanced respiratory burst and superoxide anion production in response to PMA, but did not influence phagocytosis of opsonized Escherichia coli. BLP far exceeds LPS as a gram-negative bacterial wall component, these findings therefore implicate BLP as an additional putative mediator of SIRS arising from gram-negative infection.

Adenosine A2A receptor activation reduces proinflammatory events and decreases cell death following intracerebral hemorrhage

The ubiquitous neuromodulator adenosine inhibits the production of several proinflammatory cytokines through activation of specific cell-surface adenosine receptors. We demonstrated recently that antisense oligonucleotides to tumor necrosis factor-alpha (TNF-alpha) are neuroprotective in a rat model of intracerebral hemorrhage. Therefore, we hypothesized that activation of adenosine receptors would provide protection against intracerebral hemorrhage-induced TNF-alpha production and inflammatory events. In vitro experiments showed that adenosine A1, A2A, and A3 receptor subtypes were present on U937 cells, and activation of these subtypes inhibited TNF-alpha production with a rank order of A2A > > A1 > A3. Prolonged treatment of U937 cells with the A2A receptor agonist 2-p-(carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS 21680) desensitized adenosine A2A, A1, and A3 receptors. CGS 21680 administration directly into the striatum immediately prior to the induction of intracerebral hemorrhage inhibited TNF-alpha mRNA and, 24 hours following induction, reduced parenchymal neutrophil infiltration (p < 0.001) and TUNEL-positive cells (p < 0.002) within and bordering the hematoma. These results suggest that pharmacological strategies targeting A2A receptors may provide effective inhibition of acute neurotoxic proinflammatory events that occur following intracerebral hemorrhage.

Self-rated health and limiting longstanding illness: inter-relationships with morbidity in early adulthood

BACKGROUND

Self-rated health and limiting longstanding illness are both widely used global measures of health, but understanding is poor of their meaning and validity at younger ages.

METHODS

We examined the association between self-rated health and limiting longstanding illness and specific health problems at two ages (23 and 33 years), and assessed change over the 10-year period for each health measure relative to another. Longitudinal data were taken from the nationally representative British birth cohort for which health measures were obtained at ages 23 and 33.

RESULTS

Self-rated health and limiting longstanding illness were strongly associated with each other as well as with specific health problems, particularly with serious conditions (e.g. epilepsy, cancer, diabetes) and more weakly with less serious conditions (e.g. eczema and hay fever). Rating of overall health and limiting longstanding illness was highly stable during the 10-year period with most, but not all, health change reflecting a deterioration in health status. Deterioration in limiting illness corresponded to an even greater health decline in specific conditions.

CONCLUSIONS

Self-rated health and limiting longstanding illness are valid health measures appropriate for use in general health surveys.

Psychological distress and work and home roles: a focus on socio-economic differences in distress

BACKGROUND

Home and work factors have been linked to psychological status, but less is known about their contribution to social inequalities in psychological status. We examine whether social inequalities in psychological distress can be explained by work-home factors and whether the impact of these potential explanatory factors is similar for men and women.

METHODS

Data are from the 1958 British birth cohort study. We sought to explain social class differences in psychological distress at age 33. Explanatory factors were classified as work-home roles: i.e. employment, marital status, domestic responsibility, children and elderly care; and work-home characteristics: i.e. job-strain, insecurity, unsocial working hours, youngest child's age, number of children and level of involvement in childcare.

RESULTS

A social gradient in psychological distress was found: odds ratios for classes IV and V v. I and II were 2.65 (men) and 3.02 (women). Work factors had consistently stronger associations with psychological distress and with social class among men than women. Work factors had a greater impact on class differences in psychological distress in men. Associations for home roles and characteristics were less consistent and their combined effect on class differences in distress was negligible for both sexes.

CONCLUSION

Explanations for the social gradient differ for men and women. Work may be more important for men than women, but the impact of home factors was not strong during the early adulthood of this cohort.

Diminished adenosine A1 receptor expression on macrophages in brain and blood of patients with multiple sclerosis

The nucleoside adenosine has been shown to control the production of proinflammatory molecules through its actions on cell surface purine receptors. Previously, we have reported that the adenosine A1 receptor (A1AR) regulates tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) expression and exhibits diminished function in patients with multiple sclerosis (MS; Mayne et al., Ann Neurol 1999;45:633-639). In the present study, A1AR expression in both brain and peripheral blood mononuclear cells (PBMC) from MS and control groups was characterized by fluorescence-activated cell sorting (FACS), reverse transcriptase-polymerase chain reaction (RT-PCR), and immunohistochemical analyses. FACS analyses of PBMC revealed that A1AR expression was chiefly detectable on CD14-positive cells and was reduced by 53.1% (p < 0.01) in MS patients compared to controls. A1AR mRNA levels were reduced by 43.1% (p < 0.001) in the brains of MS patients compared to patients with other neurological diseases and controls. A1AR protein expression in brain was detected primarily in CD45-positive glial cells and was markedly diminished in MS patients. The analysis of A1AR transcripts in the brain revealed that the A1AR-beta transcript was diminished (49.2%) in MS patients compared to controls (p < 0.002). These results indicate that the A1AR, expressed principally on cells of monocyte/macrophage lineage in both brain and blood, is selectively diminished in MS patients. Reduction of the A1AR-beta transcript in MS patients suggests that dysregulated splicing may influence A1AR protein levels, potentially leading to increased macrophage activation and central nervous system inflammation.

Human immunodeficiency virus type 1 clade A and D neurotropism: molecular evolution, recombination, and coreceptor use

Human immunodeficiency virus type 1 (HIV-1) non-B clade viral infections of the brain have not been studied to date. Among nine AIDS patients from Nairobi, Kenya, infected with HIV-1 A (N = 5) or D (N = 4) clade strains, brain-derived HIV-1 env sequences displayed greater evolutionary distance than B clade brain-derived viruses (P < 0.001). Similarly, molecular diversity between matched brain and spleen env clones was clade-dependent and concentrated in the hypervariable V4 region (P < 0.001), with phylogenetic clustering of sequences derived from the same organ. Brain-derived A and D clade sequences displayed significantly lower ratios of nonsynonymous/synonymous substitution rates (d(N)/d(S)) compared to matched spleen-derived clones and brain-derived B clade viruses. Interclade recombination events were infrequently observed among the present env sequences. A chimeric virus containing the C2V3 region from an A clade brain-derived sequence preferentially used CD4 and CCR5 for infection. These findings demonstrate that differences in molecular diversity in brain-derived sequences were dependent on the individual clade and domain within the env gene, but both B and non-B clade brain-derived viruses exhibit a preference for CCR5 as a coreceptor.

HIV-1 reverse transcriptase sequence in plasma and cerebrospinal fluid of patients with AIDS dementia complex treated with Abacavir

OBJECTIVE

To assess HIV-1 RNA levels and the relationship between HIV-1 reverse transcriptase (RT) genotype from plasma and cerebrospinal fluid (CSF) during treatment with abacavir (Ziagen, ABC) or placebo in combination with stable background therapy (SBG) in subjects with AIDS dementia complex (ADC) (study CNA3001).

DESIGN

One-hundred and five HIV-1 infected adults with ADC were randomized to receive either ABC (600 mg twice daily) or ABC-matched placebo (twice daily) in addition to SBG for 12 weeks.

METHODS

Plasma and CSF were collected for population sequencing at baseline and week 12 (CSF optional). Sequences were analyzed for mutations associated with resistance to nucleoside reverse transcriptase inhibitors (NRTI).

RESULTS

Sixty out of sixty-seven subjects with baseline plasma HIV-RT sequence data harbored virus with > or = 1 NRTI-associated mutations; 50 out of 67 had the M184V mutation. At week 12, more subjects in the ABC group had plasma HIV-1 RNA < or = 400 copies/ml than the SBG group (46% versus 13%, P = 0.002). Non-response to ABC was associated with multiple baseline zidovudine (ZDV)/stavudine (d4T)-associated mutations. Baseline RT mutation patterns differed in 14 out of 21 (67%) paired samples from plasma and CSF. Four subjects experienced > 1 log10 copies/ml reductions in CSF HIV-1 RNA, two in the absence of reductions in plasma HIV-1 RNA and two with undetectable plasma HIV-1 RNA at baseline.

CONCLUSIONS

Substantial decreases in plasma and CSF HIV-1 RNA following addition of ABC were not precluded by baseline HIV-1 NRTI-associated mutations, including the M184V mutation, but non-responders commonly harbored multiple ZDV/d4T-associated mutations. HIV-1 RNA responses and RT genotype appear to be discordant between CSF and plasma in some subjects.

Physical and psychological effects of injury. Data from the 1958 British birth cohort study

BACKGROUND

There is only scant evidence for the long-term health effects of road traffic injuries. We therefore assessed the extent to which motor vehicle driver injuries influence limiting long-standing illness and psychological distress using data from a nationwide study (the 1958 British birth cohort) in early adulthood.

METHODS

Information was obtained on driver injuries occurring between ages 23 and 33 years and limiting illnesses and psychological distress at age 33 years. The risks of injury-related adverse consequences were derived using logistic regression and expressed as odds ratios (ORs) and 95% confidence intervals.

RESULTS

A single injury was associated with limiting illness (OR = 2.01 and 95% CI: 1.38-2.94). The association between a single injury and psychological distress was strong for a recent injury occurring between ages 30 and 33 years (OR = 1.86 and 95% CI: 1.24-2.81), but not for injuries occurring earlier on. The population attributable fraction for limiting illness with one injury was 3.8% (range 1.7-5.3%) and with two or more injuries was 1.0% (range 0.5-1.3%). After controlling for potential confounding factors the corresponding figures were 4.2% (range 2.2-5.6%) and 1.1% (range 0.5-1.3%) respectively.

CONCLUSIONS

Driver injuries are associated with a substantial increase in disability and, also in the short term, with increases in psychological distress. These results highlight the need for identifying effective strategies for the prevention of road traffic injuries as well as more effective approaches for rehabilitation of the injured.

Retroviral diseases of the nervous system: pathogenic host response or viral gene-mediated neurovirulence?

Retroviruses represent an important group of RNA viruses that cause a spectrum of nervous system diseases. Furthermore, newly recognized retroviral infections of the nervous system and some retroviral vectors or proteins used for gene delivery raise potential safety concerns. This article highlights different retroviruses and their causative mechanisms of nervous system disease, or neurovirulence. Specific sequences within retroviral genes might determine the development of neurovirulence. Conversely, neurovirulent retroviruses also activate host immune responses, resulting in a neuropathogenic cascade that is mediated by pro-inflammatory and neurotoxic molecules, ultimately culminating in neuronal death. Thus, retroviral infections of the nervous system illustrate a molecular interplay between distinct infectious agents and pathogenic host responses, which results in neurovirulence.

Seroprevalence of infection with Mycobacterium avium subspecies paratuberculosis, bovine leukemia virus, and bovine viral diarrhea virus in maritime Canada dairy cattle

The purpose of this study was to survey the seroprevalence of infection with the agents of production-limiting diseases in dairy cattle in New Brunswick, Nova Scotia, and Prince Edward Island. In 30 randomly selected herds per province, 30 cattle per herd were randomly selected and tested for antibodies to bovine leukemia virus (BLV) and Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis), while 5 unvaccinated cattle over 6 months of age were tested for antibodies to bovine viral diarrhea virus (BVDV). For BLV, 20.8% (15.8% to 27.0%) of cows were positive, and 70.0% (60.3% to 79.7%) of herds had at least one positive cow. In BLV-positive herds, the average BLV prevalence was 30.9% (24.8% to 37.2%). For M. paratuberculosis, 2.6% (1.8% to 3.9%) of cows were positive, and 16.7% (8.8% to 24.5%) of herds had at least 2 M. paratuberculosis-positive cows. In M. paratuberculosis-positive herds, the average M. paratuberculosis prevalence was 8.5% (6.9% to 10.1%). For BVDV, 46.1% (35.5% to 56.7%) of herds had at least 1 BVDV-positive animal with a titer greater than or equal to 1:64.

Aboriginals with multiple sclerosis: HLA types and predominance of neuromyelitis optica

BACKGROUND

MS is common in people of northern European ethnicity who live in northern geographic areas; however, MS is rarely identified among aboriginal peoples living in the same areas.

OBJECTIVES

To determine the prevalence, clinical features, HLA type, and viral infections associated with MS among aboriginals in Manitoba, Canada.

METHODS

A retrospective study was performed in which the clinical features of all aboriginal patients with MS together with HLA type and human herpesvirus-6, HIV-1, human T-cell lymphotropic virus-1, and endogenous retrovirus associated with MS (MSRV) infections were analyzed and compared with results from nonaboriginal patients with MS.

RESULTS

Seven aboriginals with MS were identified with a period prevalence among aboriginals of 40:100,000. Clinical features included relapsing-remitting (n = 6) or primary progressive (n = 1) phenotypes with aggressive disease courses and frequent involvement of optic nerves and spinal cord (n = 5) compared with nonaboriginal patients. Autopsy of one patient showed necrosis and eosinophil infiltrates in a cervical spinal cord lesion and a demyelinated optic nerve. Analysis of HLA alleles at the DRB1 and DQB1 loci indicated that the HLA types detected were common in aboriginals, but there were no HLA alleles previously associated with the development of MS. Analysis of the copy number of MSRV did not show differences among aboriginals and nonaboriginals with or without MS.

CONCLUSIONS

Aboriginals of Algonkian background are at increased risk for an aggressive type of MS, resembling neuromyelitis optica, which is resistant to conventional MS treatments and occurs independently of HLA alleles previously associated with MS.

HIV-1 Tat neurotoxicity is prevented by matrix metalloproteinase inhibitors

The release of potentially neurotoxic molecules by HIV-infected brain macrophages is accompanied by neuronal injury and death that results in the development of HIV-associated dementia (HAD). Among the potential neurotoxins implicated in the development of HAD is the HIV-1 transactivating protein, Tat. To investigate the mechanism by which Tat causes neurotoxicity, brain-derived Tat sequences from nondemented (Tat-ND) and demented (Tat-HAD) AIDS patients, which differed primarily in the augmenting region of Tat, were expressed in U937 monoblastoid cells and primary human macrophages. Cells expressing Tat-HAD protein exhibited elevated matrix metalloproteinase (MMP)-2 and -7 release and activation, but cells expressing Tat-ND did not exhibit enhanced MMP expression. Conditioned media from Tat-HAD-transfected cells caused significantly greater neuronal death (15.4 +/- 4.3%) than did Tat-ND (4.4 +/- 2.1%) or nontransfected (2.1 +/- 0.8%) cell-derived conditioned media. The neurotoxicity induced by Tat-HAD was inhibited by anti-MMP-2 or -7 antibodies (p < 0.005) but not by antibodies against MMP-9 or Tat. Similarly, scid/nod mice receiving striatal implants of Tat-HAD-transfected cells exhibited greater neurobehavioral abnormalities and neuronal loss (p < 0.005) than did animals receiving Tat-ND or nontransfected cells, which were reduced by treatment with the MMP inhibitor prinomastat (p < 0.005). These findings indicate that Tat causes neuronal death through an indirect mechanism that is Tat sequence dependent and involves the induction of MMPs.

Very low prevalence of bovine immunodeficiency virus infection in western Canadian cattle

Bovine immunodeficiency virus (BIV) is a lentivirus that causes disease in cattle. Despite the large cattle industry in western Canada, the presence of BIV has not been examined to date. Genomic DNA, derived from semen and buffy coat samples, was analyzed by nested polymerase chain reaction (PCR) using specific primers for the gag, pol, and env genes of BIV. Despite utilizing a procedure that detected a minimum of 10 proviral copies, BIV sequences were not amplified in any of 317 buffy coat and 50 semen samples that were obtained from an archive that included 27 cattle breeds, collected from different sources in Alberta (1980-1999). In the 367 DNA samples examined, there was no evidence of BIV infection, suggesting that the prevalence of BIV infection was very low.

Antisense oligodeoxynucleotide inhibition of tumor necrosis factor-alpha expression is neuroprotective after intracerebral hemorrhage

BACKGROUND AND PURPOSE

Tumor necrosis factor-alpha (TNF-alpha) expression is increased in brain after cerebral ischemia, although little is known about its abundance and role in intracerebral hemorrhage (ICH). A TNF-alpha-specific antisense oligodeoxynucleotide (ORF4-PE) was used to study the extent to which TNF-alpha expression influenced neurobehavioral outcomes and brain damage in a collagenase-induced ICH model in rat.

METHODS

Male Sprague-Dawley rats were anesthetized, and ICH was induced by intrastriatal administration of heparin and collagenase. Immediately before or 3 hours after ICH induction, ORF4-PE was administered directly into the site of ICH. TNF-alpha mRNA and protein levels were measured by reverse transcriptase-polymerase chain reaction and immunoblot analyses. Cell death was measured by terminal deoxynucleotidyl transferase-mediated uridine 5'triphosphate-biotin nick end labeling (TUNEL). Neurobehavioral deficits were measured for 4 weeks after ICH.

RESULTS

ICH induction (n=6) elevated TNF-alpha mRNA and protein levels (P:<0.01) at 24 hours after the onset of injury compared with sham controls (n=6). Immunohistochemical labeling indicated that ICH was accompanied by elevated expression of TNF-alpha in neutrophils, macrophages, and microglia. Administration of ORF4-PE (2.0 nmol) directly into striatal parenchyma, 15 minutes before (n=4) or 3 hours after (n=6) ICH, decreased levels of TNF-alpha mRNA (P:<0.001) and protein (P:<0. 01) in the brain tissue surrounding the hematoma compared with animals treated with saline alone (n=6). Mean+/-SEM striatal cell death (cells per high-powered field) was also reduced in animals receiving ORF4-PE (34.1+/-5.0) compared with the saline-treated ICH group (80.3+/-7.50) (P:<0.001). ORF4-PE treatment improved neurobehavioral deficits observed at 24 hours (P:<0.001) after induction of ICH (n=6) compared with the untreated ICH group (n=6). This improvement was maintained at 28 days after hemorrhage induction (P:<0.001).

CONCLUSIONS

These results indicate a pathogenic role for TNF-alpha during ICH and demonstrate that reducing TNF-alpha expression using antisense oligodeoxynucleotides is neuroprotective.

Use of the ultrasonic dissecting scalpel in laparoscopic cholecystectomy

BACKGROUND

We evaluated the use of the ultrasonically activated (harmonic) scalpel (HS) in the performance of laparoscopic cholecystectomy (LC).

METHODS

A total of 282 consecutive patients, 64 of whom had acute cholecystitis at the time of surgery, underwent LC using HS dissection. Indications for surgery included chronic pain (180 cases), episodes of acute cholecystitis (89 cases), pancreatitis (five cases), and jaundice (seven cases). Twenty-seven patients had preoperative endoscopic retrograde cholangiopancreatography (ERCP).

RESULTS

The mean operating time was 29 +/- 9 mins. Eleven procedures were converted to open surgery, (four due to bleeding, six due to unclear anatomy, and one due to an inflammatory mass caused by gangrene/perforation). Complications occurred in 14 patients. They included minor port site infection (four cases), pulmonary atelectasis (three cases), urinary retention (two cases), intraoperative catheterization not routinely performed, bile leak (two cases, both from cystic duct; one of the cystic duct leaks occurred because of dislodgement of the occluding clip, the other may have been due to duct injury from the clip), pulmonary embolus (one case), and myocardial infarction (one case). Neither of the latter complications were fatal. One patient required a postoperative transfusion due to a fall in hematocrit of 3.2 gr/dl.

CONCLUSIONS

LC performed with the HS is feasible and effective. Operating time and blood loss were minimal, and the conversion rate was low (3.9%). There were no bile duct injuries. Use of the HS makes dissection easier, thereby helping to reduce operative time and lower the need for conversion to open surgery.

Dopamine attenuates the chemoattractant effect of interleukin-8: a novel role in the systemic inflammatory response syndrome

Activated neutrophil (PMN) adherence to vascular endothelium comprises a key step for both transendothelial migration and initiation of potentially deleterious release of PMN products. The biogenic amine, dopamine (DA), has been used for several decades in patients to maintain hemodynamic stability. The effect of dopamine on PMN transendothelial migration and adhesion receptor expression and on the endothelial molecules, E-selectin and ICAM-1, was evaluated. PMN were isolated from healthy controls, stimulated with lipopolysaccharide (LPS), and tumor necrosis factor-alpha (TNF-alpha) and treated with dopamine. CD 11b and CD 18 PMN adhesion receptor expression were assessed flow cytometrically. In a separate experiment, the chemoattractant peptide, IL-8, was placed in the lower chamber of transwells, and PMN migration was assessed. Human umbilical vein endothelial cells (HUVEC) were stimulated with LPS/TNF-alpha and incubated with dopamine. ICAM-1 and E-selectin endothelial molecule expression were assessed flow cytometrically. There was a significant increase in transendothelial migration in stimulated PMN compared with normal PMN (40 vs. 14%, P < 0.001). In addition, PMN CD11b/CD18 was significantly upregulated in stimulated PMN compared with normal PMN (252.4/352.4 vs. 76.7/139.4, P < 0.001) as were endothelial E-selectin/ICAM-1 expression compared with normal EC (8.1/9 vs. 3.9/3.8, P < 0.05). After treatment with dopamine, PMN transmigration was significantly decreased compared with stimulated PMN (8% vs. 40%, P < 0.001). Furthermore, dopamine also attenuated PMN CD11b/CD18 and the endothelial molecules E-selectin and ICAM-1 compared with stimulated PMN/EC that were not treated dopamine (174/240 vs. 252/352, P < 0.05 and 4/4.4 vs. 8.1/9, P < 0.05. respectively). The chemoattractant effect of IL-8 was also attenuated. These results identify for the first time that dopamine attenuates the initial interaction between PMN and the endothelium, and consequently, modulates PMN exudation. Thus, biogenic amines, including dopamine, may function as anti-inflammatory cytokines.

Lentivirus infection in the brain induces matrix metalloproteinase expression: role of envelope diversity

Infection of the brain by lentiviruses, including human immunodeficiency virus (HIV) and feline immunodeficiency virus (FIV), causes inflammation and results in neurodegeneration. Molecular diversity within the lentivirus envelope gene has been implicated in the regulation of cell tropism and the host response to infection. Here, we examine the hypothesis that envelope sequence diversity modulates the expression of host molecules implicated in lentivirus-induced brain disease, including matrix metalloproteinases (MMP) and related transcription factors. Infection of primary macrophages by chimeric HIV clones containing brain-derived envelope fragments from patients with HIV-associated dementia (HAD) or nondemented AIDS patients (HIV-ND) showed that MMP-2 and -9 levels in conditioned media were significantly higher for the HAD clones. Similarly, STAT-1 and JAK-1 levels were higher in macrophages infected by HAD clones. Infections of primary feline macrophages by the neurovirulent FIV strain (V(1)CSF), the less neurovirulent strain (Petaluma), and a chimera containing the V(1)CSF envelope in a Petaluma background (FIV-Ch) revealed that MMP-2 and -9 levels were significantly higher in conditioned media from V(1)CSF- and FIV-Ch-infected macrophages, which was associated with increased intracellular STAT-1 and JAK-1 levels. The STAT-1 inhibitor fludarabine significantly reduced MMP-2 expression, but not MMP-9 expression, in FIV-infected macrophages. Analysis of MMP mRNA and protein levels in brain samples from HIV-infected persons or FIV-infected cats showed that MMP-2 and -9 levels were significantly increased in lentivirus-infected brains compared to those of uninfected controls. Elevated MMP expression was accompanied by significant increases in STAT-1 and JAK-1 mRNA and protein levels in the same brain samples. The present findings indicate that two lentiviruses, HIV and FIV, have common mechanisms of MMP-2 and -9 induction, which is modulated in part by envelope sequence diversity and the STAT-1/JAK-1 signaling pathway.

Nutritional and other influences in childhood as predictors of adult obesity

It has been proposed that there are critical periods during childhood that influence the development of obesity, including gestation and early infancy, the period of adiposity rebound that occurs between ages 5 and 7 years, and adolescence. Despite an extensive literature, there is to date only modest evidence for most of the factors such as nutrition, physical activity and other behavioural factors that are suspected as playing a role in the development of obesity. A recent review of this evidence (Parsons et al. 1999) showed, however, a consistent relationship between socio-economic status (SES) of origin and adult obesity, whereby those from lower SES backgrounds were fatter subsequently in adulthood. This association appeared to apply to both men and women, a finding that contrasts with the trends observed in cross-sectional studies, of an association with SES for women only. There are several potential explanations for the SES of origin-adult obesity relationship. SES of origin may be confounded by parental body size; studies to date provide insufficient evidence of an independent association with SES after allowing for parental body size. Alternatively, environment in early life (for which SES of origin is a proxy measure) may have a long-term impact on obesity later in adulthood, through one or more of several processes. Three major potential explanations can be identified: (1) nutrition in infancy and childhood, either over- or undenutrition, followed subsequently by overnutrition; (2) psychological factors, possibly involving emotional deprivation in childhood; (3) cultural or social norms regarding dietary restraint and attitudes to fatness that may be acquired during childhood.

Autopsy study of HIV-1-positive and HIV-1-negative adult medical patients in Nairobi, Kenya

HIV infection has now been consistently identified as the major cause of death in young Africans in both urban and rural areas. In Africa, several studies have defined the clinical presentation of HIV disease but there have only been a limited number of autopsy studies. Because of the scarcity of autopsy data and the possibility of differing type and frequency of opportunistic infections between different geographic locations we set out to study consecutive new adult medical admissions to a tertiary referral hospital in Nairobi and perform autopsies on a sample of HIV-1-positive and HIV-1-negative patients who died in the hospital ward. Basic demographic data were collected on all patients admitted to two acute medical wards over an 11-month period. Final outcome and final clinical diagnoses were recorded at discharge or death. An autopsy examination was requested if the patient died in the ward. Autopsy examination was performed in 75 HIV-1-positive (40 men, 35 women) and 47 HIV-1-negative (28 men, 19 women) adults who died in the hospital. This represented 48.4% of all HIV-1-positive deaths and 33.3% of all HIV-1-negative deaths. Tuberculosis (TB) and bacterial and interstitial bronchopneumonia accounted for 96% of the major pathology in patients found to be HIV-1-positive at autopsy. TB was present in half the HIV-1-positive autopsy patients and was disseminated in over 80% of cases. Meningeal involvement was present in 26% of those with disseminated TB. By contrast, TB was much less common in the HIV-1-negative patients at autopsy in whom bacterial bronchopneumonia and malignancies were the most common pathologies. The type pathology found in the HIV-1-positive autopsy patients was not different than that found in other areas in Africa so far studied.

Back pain and obesity in the 1958 British birth cohort. cause or effect?

An association between obesity and back pain has been observed, but the underlying causal direction is uncertain. We examined the temporal sequence among back pain, BMI, and weight gain using data from the 1958 British birth cohort followed to age 33 (4395 men and 4468 women). Heights and weights were measured at ages 7 and 33, and self-reported at age 23. Back pain was classified as: chronic, incident, early onset but recovered, and never. Those with chronic pain gained more weight between ages 23 and 33 than those with no pain, significantly for women (7.39 kg vs. 6.29 kg). Women who were obese at age 23 years had an elevated risk of subsequent back pain onset (32-33 years) (adjusted OR = 1.78). No significant relationships were found for men. The risk of pain onset among women was evident in relation to BMI at baseline (age 23) and cannot therefore be explained by an effect of back pain on adiposity.

AIDS- and non-AIDS-related PML association with distinct p53 polymorphism

A population-based analysis of progressive multifocal leukoencephalopathy (PML) showed PML frequencies of 5.1% among patients with AIDS and 0.07% among patients with hematologic malignancies, but similar clinical features of PML in both groups. Sequencing of the p53 gene, exon 4, showed heterozygosity (Arg-Pro) at codon 72 in five of six PML patients. These findings indicate that frequencies of non-AIDS- and AIDS-related PML differ markedly but p53 polymorphisms may influence the occurrence of PML in both groups.