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Biomedical subjects

A Poli

Publications and source records attributed to A Poli.

At least 91 records · Page 5Linked to original sources

Significance of ST-segment elevation during dobutamine-stress echocardiography in patients with acute myocardial infarction treated with thrombolysis.

BACKGROUND: Stress-induced ST-segment elevation in patients with recent myocardial infarction treated with thrombolysis has not been extensively investigated. According to the results of previous studies it may represent residual myocardial ischaemia or dyskinesia in the infarcted region. The aim of the study was to analyse the significance of dobutamine-induced ST-segment elevation in the infarcted area in a consecutive group of patients (n = 42, 41 men, mean age 53 +/- 7 years) with a first acute myocardial infarction treated with thrombolysis within 6 h from symptoms onset. METHODS AND RESULTS: All patients underwent dobutamine-stress echocardiography (up to 40 micrograms.kg-1.min-1 + atropine) 7 +/- 3 days from the acute event and coronary arteriography within 1 month from the test. Significant ST-segment elevation was defined as a shift > or = 1 mm during dobutamine compared to baseline in at least two contiguous infarct-related leads; a correlation was made between the site of ST-segment elevation and wall motion changes during dobutamine. Dobutamine-induced ST-segment elevation in 23/42 (55%) patients (group 1) while no changes were observed in 19/23 (45%) patients (group 2). Compared to group 2, group 1 patients showed a higher asynergy score index (1.72 +/- 0.24 vs 1.50 +/- 0.32, P < 0.02) and a higher number of asynergic segments (5.04 +/- 1.9 vs 4.11 +/- 1.8), at baseline, a higher incidence of baseline and/or stress-induced dyskinesia (39 vs 10%, P < 0.05) in the infarct-related region and a higher percentage of occluded infarct-related arteries (48 vs 0%, P < 0.001). In the 42 patients studied, a significant correlation was found between baseline ST-segment elevation and baseline asynergy score index (RS = 0.56, P < 0.001) and between ST-segment elevation and asynergy score index at peak stress (RS = 0.55, P < 0.001). The incidence of reversible wall motion abnormalities indicative of myocardial viability and residual myocardial ischaemia was similar in the two groups (87 vs 84% and 74 vs 68%, respectively), while the number of segments with irreversible akinesia indicative of myocardial necrosis was higher in group 1 compared to group 2 (1.5 +/- 1.4 vs 0.9 +/- 1.4). Among the 23 patients of group 1 with dobutamine-induced ST-segment elevation, six had no reversible wall motion abnormalities indicative of myocardial ischaemia; of the 17 patients with myocardial ischaemia, 11 had > or = 50% and six had < or = 50% of basally asynergic segments showing reversible wall motion abnormalities. CONCLUSIONS: In patients with recent thrombolyzed myocardial infarction dobutamine-induced ST-segment elevation is associated with a larger akinetic area in basal conditions and either with reversible wall motion abnormalities indicative of myocardial ischaemia or with irreversible or minimally reversible wall motion abnormalities in the infarct area during the test. Thus, dobutamine echocardiography provides useful information for the interpretation of stress-induced ST-segment elevation and clinical management of these patients.

Adrenergic beta-Antagonists↗

Posatirelin in the treatment of vascular dementia: a double-blind multicentre study vs placebo.

INTRODUCTION: The usefulness of posatirelin (L-pyro-2-aminoadipyl-L-leucyl-L-prolinamide), a synthetic peptide having modulatory activity on the monoaminergic and cholinergic systems and neurotrophic effects, was evaluated in vascular dementia. PATIENTS AND METHODS: A multicentre, parallel groups, double-blind clinical study vs placebo was carried out with patients suffering from probable vascular dementia according to the NINDS-AIREN criteria. The study consisted of a two-week run-in of a once daily, orally administered, placebo phase, followed by 12 weeks of intramuscular treatment with posatirelin 10 mg/ml or placebo given once a day and a follow-up after one month's withdrawal. Efficacy was assessed using the Gottfries-Bråne-Steen (GBS) Rating Scale for dementia, the Randt Memory Test and the Toulouse-Piéron Attention Test. Data were evaluated using analysis of variance and covariance. RESULTS: As regards GBS scores, patients treated with posatirelin showed a significant improvement in intellectual performance, in orientation, motivation and memory as compared to controls. The improvement of memory performance was also confirmed by the acquisition score and memory index of the Randt Memory Test. At the end of the follow-up period the differences between treatments were still maintained. Tolerability was good. CONCLUSIONS: The significant improvement observed in cognitive functions, attention and motivation of demented patients treated with posatirelin suggests the potential usefulness of this drug in vascular dementia. Furthermore, the presence of a long-lasting effect after drug withdrawal suggests the possibility of administering the drug cyclically.

Aged↗

Comparison of dobutamine stress echocardiography with dipyridamole stress echocardiography for detection of viable myocardium after myocardial infarction treated with thrombolysis.

OBJECTIVE: To compare the ability of dobutamine and dipyridamole stress echocardiography to detect functional recovery of stunned but viable myocardial regions early after acute myocardial infarction, and to predict late functional recovery of the reperfusion salvaged myocardium within the infarct area. METHODS: Within 10 d of acute myocardial infarction, 51 patients--30 anterior and 21 inferior, 44 Q wave and seven non-Q-wave infarction--were submitted to a dobutamine echocardiography test at low dose (5-10 micrograms/kg/min over 5 min) and high dose (20-40 micrograms/kg/min over 3 min) and to dipyridamole echocardiography test (0.56 mg/kg over 4 min + 0.28 mg/kg over 2 min) on different days and in random order, after interruption of any vasoactive drug. Resting echocardiography was repeated at two months in 41 of 51 patients (80%). Regional wall motion of the left ventricle was analysed in a semiquantitative manner on a 14-segment model. Viability was defined as improvement of one grade or more of at least two basally asynergic segments in the infarcted area. RESULTS: Regional functional recovery was detected by low dose dobutamine in 38/51 patients (75%) and in 147/308 (48%) of basally asynergic segments, compared to 25/51 patients (49%; P < 0.001) and 78/308 segments (25%; P < 0.001) only identified by dipyridamole. Late spontaneous functional recovery was detected in 24/41 patients (59%) and in 78/254 basally asynergic segments (31%). The sensitivity of dobutamine and dipyridamole echocardiography for predicting spontaneous functional recovery was 72% and 51% respectively (P < 0.001), specificity 68% and 82% (P < 0.001), positive predictive value 50% and 56%, and negative predictive value 85% and 79%. CONCLUSIONS: In comparison with dipyridamole in patients with thrombolysed myocardial infarction, dobutamine induces regional functional recovery. This suggests that dobutamine is more sensitive in showing the presence of viable myocardium within the infarct zone, though it has a lower specificity in predicting delayed spontaneous functional recovery of non-contractile but still viable areas.

Coronary Angiography↗

Neurotoxic effects of DSP-4 on the noradrenergic system of the goldfish brain.

The substance N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) is a neurotoxin with selective and long-lasting effects on the noradrenergic (NA) neurons of mammalian brains. The present study examines the effects of this toxin on the noradrenergic system of the goldfish brain. Single doses (50 mg/kg body weight) of DSP-4 reduce the immunoreactivity of the NA synthesizing enzyme dopamine-beta-hydroxylase (DBH), as revealed by immunohistochemistry 7 and 12 days after toxin administration. The depletion involves the DBH-positive fibres and spares the DBH-positive cell bodies. Dopamine-beta-hydroxylase immunoreactivity, 40 days after toxin administration, showed a complete recovery. Ultrastructural investigations confirmed that DSP-4 toxicity affects only nervous fibres and terminals, sparing cell bodies. Administration of DSP-4 also produced a marked decrease of noradrenaline (NA) levels in the goldfish brain, seven days later, while dopamine (DA) and serotonin (5-HT) levels were unaffected by toxin injection. The reduction of NA levels induced by DSP-4 was prevented by the concomitant administration of the NA uptake inhibitor desipramine. Noradrenaline levels measured 40 days after toxin administration show that DSP-4 toxicity was completely reversed. The results suggest a pronounced plasticity of the noradrenergic system in the goldfish brain.

Adrenergic Agents↗

Blood and serous cysts in the atrioventricular valves of the bovine heart.

A survey of 30,907 slaughterhouse cattle (5,984 calves, 15,937 young adult, 8,986 cows) was carried out to determine the incidence of blood and serous cysts on atrioventricular valves. The cysts were classified by their content (blood/serous fluid), location (mitral/tricuspid valve), and size. Cyst wall samples were processed for histology, immunohistochemistry for factor VIII-related antigen, and transmission electron microscopy. The content of some cysts was studied by electrophoresis and biochemical and microbiologic methods. Older cows had a higher incidence (16.2%) than younger animals (11.5% in calves, 7.9% in steers, 6.4% in heifers), suggesting that the lesions may be acquired. Blood cysts were often present on both atrioventricular valves; serous cysts prevailed on the mitral valve. Cysts of both types were larger in older animals; serous cysts were larger than the blood cysts. Histologically, blood cysts contained fresh blood, and serous cysts were filled with a hyaline fluid devoid of cells, sterile, and biochemically similar to lymph. All the cysts were lined with endothelium, but a positive immunostaining for the factor VIII-related antigen was appreciable only in blood cysts. Ultrastructurally, the endothelium was composed of flat endothelial cells holding several cytoplasmic filaments, lying in blood cysts on a continuous and often laminated basal lamina with many cytoplasmic projections. The results support the hypothesis that cysts of the atrioventricular valves derive from the dilation of blood and lymphatic valvular vessels, do not regress with age, and are mainly the result of mechanical effects.

Aging↗

[Results and prognostic significance of echocardiography-dobutamine + atropine test in recent non-Q wave myocardial infarction].

BACKGROUND: Patients with non-Q wave myocardial infarction (NQ AMI) are usually considered to have an increased risk of recurrent ischemic events and reinfarction. We wished to assess whether dobutamine stress echocardiography with the addition of atropine (DOB-E + ATRO) can detect jeopardized myocardium after a recent NQ AMI and to assess the prognostic significance of this test in a group of patients with a first uncomplicated NQ AMI: METHODS AND RESULTS: Fourty-one consecutive patients (38 men, mean age 52 +/- 9 years, 31 anterior, 68% treated with thrombolysis) underwent low and high-dose DOB-E (from 5 to 40 mcg/kg/min); ATRO was added in 14/41 (34%) patients. A significant deterioration of wall motion in the infarcted region (IR) indicative of residual myocardial ischemia was present in 36/41 patients (88%). Significant electrocardiographic changes and angina developed in 61% and 32% of patients, respectively. Coronary angiography was performed in 30/41 patients (73%) and showed 1-vessel coronary artery disease (CAD) in 70% of cases, multivessel CAD in 23% of cases and no significant CAD in 7% of patients. Three patients were lost at follow-up and 10 other patients were excluded from the analysis because a revascularization procedure was performed during diagnostic angiography. On a mean follow-up period of 9.5 +/- 9 months, the incidence of coronary events (re-infarction, recurrent angina, revascularization procedures) was higher (15/36 vs 1/5, 42% vs 20%) in patients with a DOB-E + ATRO positive test (1 reinfarction, 9 recurrent angina, 5 revascularized) than in those with a negative test (1 recurrent angina). CONCLUSIONS: DOB-E + ATRO early after a first uncomplicated NQ AMI documents the presence of myocardial ischemia in the IR in the great majority of patients. A positive DOB-E + ATRO was found to be associated with a higher incidence of cardiac events at follow-up, but the results of this non prospective study (high sensitivity but low specificity and predictive value for cardiac events at follow-up) suggest to utilize with caution this test for risk stratification of patients with recent NQ AMI until prospective and larger studies are performed.

Adult↗

Influence of gastric acid secretion blockade and food intake on the bioavailability of a potassium diclofenac suspension in healthy male volunteers.

The bioavailability of a single dose of a potassium diclofenac (KDIC) suspension (Flogan, Merck, 7ml, 105 mg) was studied in 13 healthy male volunteers in the fasting state (placebo phase, PLA), after gastric acid secretion blockade (subacute pretreatment with omeprazole, OME phase) and after food intake (FOOD phase). A 14-day washout period between phases was adopted. Serum samples were obtained over a 24 hour interval and the diclofenac concentrations were determined by high pressure liquid chromatography with ultraviolet detection. From the serum diclofenac concentration vs time curves, the AUC[0-infinity] (area under the concentration vs time curves from 0 to infinity), Cmax (maximum achieved concentration), tmax (time to achieve Cmax), Ke (terminal first order elimination constant), half-life values (t1/2) and AUC[0-infinity]/t1/2 ratio as an index of diclofenac clearance, were obtained. All these variables were analyzed using both parametric and non-parametric statistics. In the presence of food, KDIC absorption was delayed (as shown by lower Cmax and greater tmax values) and decreased (as shown by lower AUC[0-infinity] values), and the serum diclofenac concentration vs time curves showed a biphasic pattern. Omeprazole pretreatment did not change the absorption parameters. Both of these treatments altered the diclofenac clearance, as assessed by the AUC[0-infinity]/t1/2, t1/2 and Ke values, although the changes were not considered to be clinically significant, because of the wide therapeutic range for diclofenac. The delay in the rate of diclofenac absorption produced by food intake was not due to an increase in the gastric pH, and could be of particular importance when rapid analgesia is desired.

Administration, Oral↗

Determination of ticlopidine in human plasma by high-performance liquid chromatography and ultraviolet absorbance detection.

A simple HPLC method has been developed for the determination of ticlopidine in human plasma. Plasma samples were buffered at pH 9 and extracted with n-heptane-isoamyl alcohol (98.5:1.5, v/v). Imipramine was used as internal standard. Chromatography was performed isocratically with acetonitrile-methanol-0.05 M KH2PO4 (20:25:55, v/v) at pH 3.0 containing 3% triethylamine at a flow-rate of 1 ml/min. A reversed-phase column, Supelcosil LC-8-DB, 15 cm x 4.6 mm I.D., 5 microns particle size, was used. The effluent was monitored by UV absorbance detection at 235 nm. The method showed good accuracy, precision and linearity in the concentration range 5-1200 ng/ml. The limit of quantitation was 5 ng/ml, with a precision (C.V.) of 8.91%, which is the same as that achieved by other authors with a previously published GC-MS method. The procedure described in this paper is simple and allows the routine assessment of ticlopidine plasma concentration in pharmacokinetic studies following therapeutic doses in human subjects.

Acetonitriles↗

Adenosine analogs inhibit acetylcholine release and cyclic AMP synthesis in the guinea-pig superior cervical ganglion.

The ability of adenosine agonists to modulate the electrically evoked release of acetylcholine (ACh) from [3H]choline preloaded guinea-pig superior cervical ganglia (SCG) was investigated. The adenosine A1-receptor selective agonist N6-cyclohexyladenosine (CHA) and 2-chloroadenosine (2-CADO) inhibited the evoked transmitter release, the effect being reversed by the A1-receptor selective antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), and by sulmazole (SUL), which blocks both the A1-receptor and the adenylate cyclase inhibitory regulator Gi. In whole ganglia, CHA decreased both the basal and the forskolin (FSK)-stimulated cyclic AMP synthesis. The latter effect was again prevented by the A1 antagonist DPCPX. These results are compatible with the existence, in the guinea-pig SCG, of adenosine A1-receptors, part of which are located on the presynaptic nerve terminals mediating an inhibition of ACh release.

Acetylcholine↗

Results of dipyridamole plus atropine echo stress test for the diagnosis of coronary artery disease.

Sensitivity of dipyridamole stress echocardiography (DIP-E) has been reported to be less than ideal in particular subsets of patients such as those with less severe extent of coronary artery disease (CAD). To verify if sensitivity could be improved, ATRO (1 mg in 2 minutes) was added at the end of a negative high-dose (0.84 mg/kg over 10 minutes) DIP-E in 61 consecutive patients (58 men, aged 53 +/- 7 years) evaluated for chest pain (33%) or for detection of residual ischemia after acute myocardial infarction (AMI) or previous MI (67%). DIP-E was positive in 28/61 (46%) and negative in 33/61 (54%) patients. Additional echo positivity was obtained in 18/33 (54%) patients after ATRO. Coronary arteriography was normal in 6 patients (10%); 1-vessel CAD was diagnosed in 28 (46%), 2-vessel CAD in 16 (26%) and 3-vessel CAD in 11 (18%) cases. The sensitivity for CAD diagnosis was 49% (27/55) for DIP-E and 84% (46/55) for DIP-E+ATRO (p < 0.001). Specificity was 83% and 80%, respectively. Diagnostic accuracy increased from 52% to 83% (p < 0.001). The better diagnostic accuracy of DIP-E was mainly related to the significant increase in sensitivity of the combined test in patients with 1-vessel CAD (from 46% to 75%) (p < 0.005). At quantitative coronary evaluation, compared to patients with positive DIP-E+ATRO or negative DIP-E+ATRO test, patients with positive DIP-E had a higher mean % diameter stenosis: 80 +/- 13% vs 72 +/- 24% and 65 +/- 36%, respectively. Peak heart rate was significantly higher after the addition of ATRO vs basal and DIP alone in patients with a positive DIP-E+ATRO test. The addition of ATRO to DIP increases diagnostic accuracy of DIP-E particularly in patients with less severe extent of CAD; ATRO may be considered as a useful routine procedure for increasing diagnostic value of DIP-E test.

Angina Pectoris↗

Clinical assessment of mental decline in elderly people: a proposal for a new quantitative index.

Despite the many instruments available for assessing elderly people, there is a need for additional methods to measure mental decline that would also be applicable in cross sectional and longitudinal studies. With this purpose in mind, our group developed and checked a new instrument, the Index of Mental Decline (IMD), which consists of five clusters of items intended for the assessment of cognition, personal interrelationships, affective disorders, apathy and somatic complaints. To improve its consistency, all clusters and items were evaluated individually, according to their clinical impact. Three levels of symptom importance were determined: absent to very mild, mild to moderate, severe to very severe. Inter-rater reliability and test-retest reliability were demonstrated in a sample of 59 subjects, and proved to be satisfactory. The validity of the IMD was tested in a group of 203 patients, in whom a clinical diagnosis of probable dementia (DSM III-R criteria) had been formulated. The results suggest the effectiveness of the IMD both in quantifying mental decline and monitoring clinical symptoms. The IMD cannot be the first step of diagnostic procedure, but it can be useful for evaluating mental decline in elderly subjects with cognitive disorders. In longitudinal studies, the presence of the same caregiver or informant is compulsory.

Aged↗

Renal involvement in feline immunodeficiency virus infection: p24 antigen detection, virus isolation and PCR analysis.

Renal alterations characterized morphologically by glomerular and tubulo-interstitial lesions and clinically by a heavy proteinuria and sometimes by renal failure are frequent in feline immunodeficiency virus (FIV) infected cats. To investigate the possible role of local FIV replication in the genesis of this renal damage, renal tissues of 15 consecutive naturally infected and five non-infected cats were examined for traces of the virus by immunohistochemistry, using a monoclonal anti-p24 antibody in a streptavidin-biotin peroxidase labeled system, cultivation and polymerase chain reaction (PCR). Tubular epithelial cells as well as scattered interstitial inflammatory and glomerular cells were positive for p24 antigen in 13 cats. Viral isolation was successful in seven cats, and FIV gag DNA and RNA sequences were detected in 14 and five cats, respectively. Control cats were constantly negative. Although not conclusive, these results suggest that a direct role of FIV in the induction of the renal damage observed in infected animals is possible.

Animals↗

Biochemical and pharmacological evidence for the presence of A1 but not A2a adenosine receptors in the brain of the low vertebrate teleost Carassius auratus (goldfish).

In whole brain membranes of goldfish, 3H-chlorocyclopentyladenosine bound to adenosine A1 receptors. The A1 receptors were ubiquitously distributed in the brain with a maximum in the hypothalamus and a minimum in the spinal cord. In superfused goldfish cerebellar slices, cyclohexyladenosine inhibited the cyclic AMP accumulation stimulated by forskolin and the selective adenosine A1 receptor antagonist, 8-cyclopentyltheophylline, reversed this effect. In the same brain preparation, 30 mM K+ stimulated the release of glutamate, glutamine, glycine and GABA in a Ca(2+)-dependent manner, whereas the aspartate and taurine release was Ca(2+)-independent. Cyclohexyladenosine, in a dose-dependent manner, inhibited the 30 mM K(+)-evoked release of glutamate whereas that of aspartate was unaffected. The CHA inhibition of glutamate-evoked release was reversed by 8-cyclopentyltheophylline. The adenosine A2a receptors were not detectable in whole brain membranes of goldfish either using the specific agonist 3H-CGS 21680 or 3H-5'-N-ethylcarboxamidoadenosine. The presence of A2b seems to be suggested by the NECA stimulation of cyclic AMP accumulation, which was reversed by 8-cyclopentyltheophylline. The results, taken together, indicate that adenosine has a neuromodulatory function in the nervous system of lower vertebrates which is comparable to that described in mammalian brain.

Adenosine↗

Comparison between an enzyme-linked immunosorbent assay using a detergent-soluble Leishmania infantum antigen and indirect immunofluorescence for the diagnosis of canine leishmaniosis.

Serum samples collected from 290 dogs--186 Leishmania-infected and 104 control animals--were screened to detect the presence of specific antibodies to Leishmania infantum antigens in Tuscany, Italy. Two different techniques were compared: an indirect immunofluorescence assay (IFA) and an indirect enzyme-linked immunosorbent assay (ELISA). The ELISA was developed using a detergent-soluble antigen of L. infantum promastigotes. Triton X-100 and protease inhibitors were used as detergent and to increase reproducibility of the assay, respectively. A strong correlation between the anti-Leishmania antibody levels obtained by ELISA and those obtained using IFA was observed. The ELISA appeared to be somewhat more sensitive than IFA (99.5% vs. 98.4%), while its specificity was lower (97.1% vs. 100%), even if not significantly different. Immunoblotting analysis, using the detergent-soluble L. infantum antigen, demonstrated that proteins of M(r) 30 and 73 kDa were recognized by all positive sera, regardless of the serum titre. Furthermore, antigens of M(r) 16, 18, 26, 33, 50 and 117 kDa were also frequently reactive with a large proportion of sera from infected dogs. This ELISA demonstrated a high sensitivity and specificity as well as the IFA, and it seems to be a suitable assay for large scale epidemiological studies.

Animals↗

Regional distribution of lesions in the central nervous system of cats infected with feline immunodeficiency virus.

Neuropathological examination of the central nervous system of 13 naturally and 13 experimentally feline immunodeficiency virus (FIV)-infected cats revealed diffuse gliosis of gray and white matter and vacuolar myelinopathy in a large proportion of infected animals, sometimes associated with lymphocytic meningitis. Multinucleated giant cell formation, the hallmark of multifocal giant cell encephalitis in HIV infection, was never observed. Morphometric analysis confirmed a marked increase of GFAP reactivity in infected cats. Gliosis was mainly present in cortical structures of frontal, parietal, and occipital lobes. Only one naturally infected animal evidenced clinical symptoms of neurological damage. This study confirms that FIV provides an interesting model for studying HIV-induced cortical and subcortical brain pathology believed to be the cause of the neurological manifestations frequently observed in AIDS patients.

Animals↗

Circulating immune complexes and analysis of renal immune deposits in feline immunodeficiency virus-infected cats.

Total immunoglobulin content and concentration of immune complexes (IC) were determined in the sera of 51 cats infected with feline immunodeficiency virus (FIV) and of 40 controls. IgG and IgM were quantified by radial immunodiffusion and circulating IC (CIC) by the CIC-conglutinin assay. IgG fractions were obtained by acid elution from kidney tissues of 15 FIV-infected and five negative control cats to investigate the possible role of IC in the genesis of renal damage observed in infected animals. Mean concentrations of IgG and circulating IC were higher in FIV-infected cats than in controls (29.6 +/- 6.7 versus 23.0 +/- 1.9 mg/dl (mean +/- s.d.) P < 0.001; and 66.5 +/- 17.0 versus 27.4 +/- 19.9% I, P < 0.001, respectively), while IgM levels were only slightly increased (0.9 +/- 0.05 versus 0.87 +/- 0.04 mg/dl, P < 0.02). Immunoglobulin fractions were eluted from 10 of the 15 renal tissue samples from FIV-infected cats and were found to be polyclonal and at least partly specific for FIV antigens. These findings confirm the presence of a B cell activation in FIV-infected cats and demonstrate the presence of high levels of CIC in their sera. The presence of immune deposits in renal tissues suggests that IC might play a role in the pathogenesis of the renal damage observed in FIV-infected cats.

AIDS-Associated Nephropathy↗

Feline immunodeficiency virus: an interesting model for AIDS studies and an important cat pathogen.

The lentivirus feline immunodeficiency virus (FIV) is a widespread pathogen of the domestic cat that is mainly transmitted through bites, although other means of transmission are also possible. Its prevalence ranges from 1 to 10% in different cat populations throughout the world, thus representing a large reservoir of naturally infected animals. FIV resembles the human immunodeficiency virus (HIV) in many respects. Similarities include the structural features of the virion, the general organization and great variability of the genome, the life cycle in the infected host, and most importantly, the pathogenic potential. Infection is associated with laboratory signs of immunosuppression as well as with a large variety of superinfections, tumors, and neurological manifestations. Our understanding of FIV is steadily improving and is providing important clues to the pathogenesis of immunodeficiency-inducing lentiviruses. The cellular receptor for FIV is different from the feline equivalent of the human CD4 molecule used by HIV; nevertheless, the major hallmark of infection is a progressive loss of CD4+ T lymphocytes as in HIV infection. The mechanisms by which FIV escapes the host's immune responses are being actively investigated. FIV causes lysis of infected T cells and also appears to predispose these cells to apoptosis. Infection of macrophages and other cell types has also been documented. For reasons yet to be understood, antibody-mediated neutralization of fresh FIV isolates is very inefficient both in vitro and in vivo. Vaccination studies have provided some encouraging results, but the difficulties encountered appear to match those met in HIV vaccine development. FIV susceptibility to antiviral agents is similar to that of HIV, thus providing a valuable system for in vivo preclinical evaluation of therapies. It is concluded that in many respects FIV is an ideal model for AIDS studies.

Acquired Immunodeficiency Syndrome↗