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Biomedical subjects

P Rossi

Publications and source records attributed to P Rossi.

At least 19 recordsLinked to original sources
PubMed1992

Purification and characterization of a low-Km 3':5'-cyclic adenosine phosphodiesterase from post-meiotic male mouse germ cells.

We describe the purification and the study of the kinetic and hydrodynamic properties of a 'low Km' cAMP phosphodiesterase specifically expressed in haploid male germ cells of the mouse. The enzyme has been purified approx. 13,000-fold with respect to the activity in total cell homogenate. The purified enzyme hydrolyzed specifically cAMP with a Km of 3.3 microM and with a Vmax of 10.5 mumol of cAMP hydrolyzed/min per mg of protein. The hydrolytic activity was neither stimulated nor inhibited by cGMP, whereas it was inhibited by RO 20-1724 and Rolipram. The enzyme showed a Stokes radius of 3.8 nm and a sedimentation coefficient of 3.1 S, corresponding to a native molecular mass of 50 kDa and a frictional ratio of 1.53. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of sucrose gradient fractions of the purified enzyme showed a major band of 43 kDa copeaking with enzyme activity.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1992

Detection of antibodies to human immunodeficiency virus type I by using synthetic peptides and time-resolved fluoroimmunoassay (TR-FIA).

A simple, rapid, reproducible and sensitive peptide-Time-Resolved-Fluoroimmunoassay (TR-FIA) method is described which allows the detection of antibodies to the Human Immunodeficiency Virus type 1 (HIV-1). By using a panel of synthetic peptide antigens that covered env, gag and pol amino acid sequences, a 20 amino acid peptide (GIWGCSGKLICTTAVPWNAS) describing an immunodominant and conserved domain on the gp41 region of the BH10 clone was found to be the most reactive in this study. Optimal conditions for antigen concentration, serum dilution and incubation time were established. The peptide-TR-FIA is specific, as assessed by testing HIV-1 positive sera which included samples from AIDS, ARC patients and HIV-positive drug users. The test was used to detect HIV antibodies in 250 well characterized HIV-1 positive sera and 50 normal sera. Peptide-TR-FIA results indicate that the env peptide was highly reactive with HIV-positive sera showing a sensitivity of 100%. None of the 50 control sera showed positive reactivity against the synthetic peptide. Furthermore the peptide-TR-FIA allowed a fine titration of antibodies to defined epitopes of immunodominant HIV structural proteins that usually cannot be achieved by peptide-ELISA assays.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A novel c-kit transcript, potentially encoding a truncated receptor, originates within a kit gene intron in mouse spermatids.

We have cloned a novel c-kit mRNA of 3.2 kb expressed in postmeiotic male germ cells. This transcript initiates in the genomic region immediately upstream of the exon coding for the second box of the split c-kit tyrosine kinase domain. The open reading frame (ORF) contains 12 novel amino acids in frame with the C-terminal 190 amino acids of the c-kit protein. It lacks therefore the upstream region in the 5.5-kb c-kit mRNA encoding the extracellular and transmembrane domain, the ATP-binding site and the kinase insert domain present in the c-kit protein.

Amino Acid Sequence↗
PubMed1992

Ugandan HIV-1 V3 loop sequences closely related to the U.S./European consensus.

The third variable (V3) loop of the human immunodeficiency virus type 1 (HIV-1) envelope protein is an important determinant for virus neutralization and cell tropism. V3 loop sequences from uncultured lymphocytes obtained in 1990 from 22 Ugandan HIV-1-infected patients could, with the exception of two patients' sequences, be divided into two groups (A and B) on the basis the V3 loop size and sequence. The V3 loop consensus sequences from both groups showed a high degree of homology to a U.S./European consensus, a characteristic also reflected by the results of peptide serology. In the case of group B the difference in sequence was only five amino acids. In contrast, the V3-flanking regions for both groups showed greater homology to an earlier (1986/1987) Ugandan consensus. The discovery of these two new Ugandan V3 loop genotypes, which are closely related to the U.S./European consensus, has implications for the understanding of the evolution of HIV-1 and for the future design of a vaccine for use in Africa.

Amino Acid Sequence↗
PubMed1992

Silent versus symptomatic dipyridamole-induced ischemia after myocardial infarction: clinical and prognostic significance.

The prevalence and prognostic significance of silent myocardial ischemia were prospectively assessed in 217 patients (mean age 57 +/- 9 years, 83% male) recovering from a first uncomplicated acute myocardial infarction and undergoing a dipyridamole echocardiography test before hospital discharge. Clinical, angiographic, exercise electrocardiographic (ECG) and dipyridamole echocardiographic variables were also examined. Of the 217 patients, 89 had no echocardiographically proved dyssynergy after dipyridamole, whereas 128 had dipyridamole-induced wall motion abnormalities that were silent in 94 (Group I) and symptomatic in 34 (Group II). There was no intergroup difference with respect to dipyridamole time (i.e., the time from onset of the test to frank dyssynergy: 7 +/- 3 vs. 8 +/- 3 min; p = NS); prevalence of inferior myocardial infarction (69% vs. 71%; p = NS); ischemic ECG changes during the test (83% vs. 71%; p = NS); diabetes (8.5% vs. 6%; p = NS); ongoing medical therapy; multivessel disease (57% vs. 56%; p = NS); and baseline left ventricular ejection fraction (57 +/- 13% vs. 57 +/- 10%; p = NS). There was also no significant difference between Group I and Group II with respect to wall motion score index at peak dipyridamole effect (1.77 +/- 0.39 vs. 1.78 +/- 0.36; p = NS). Patients were followed up for 24 +/- 4 and 25 +/- 5 months, respectively (p = NS). Life table analysis revealed no difference in unstable angina, reinfarction and death between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Clinical and pharmacokinetic aspects of high dose oral baclofen therapy.

Baclofen is a centrally acting muscle relaxant used for treatment of spasticity. Some patients, to experience adequate symptomatic relief, require dosages of baclofen that significantly exceed the conventional 80 mg daily maximum advocated by the 1992 Physicians' Desk Reference. In this pilot study of baclofen kinetics and dynamics in eleven patients, the safety and efficacy of high dose baclofen was confirmed. The data suggest that the pharmacokinetics of high dose baclofen may vary from those described previously. Time-to-peak plasma levels and plasma half-lives were noted to be substantially longer than prior reports indicate. Baclofen blood levels were observed to rise gradually over time in some patients on a stable dosing regimen, probably a result of impaired renal clearance. These findings may indicate that a change in pattern of prescription is warranted and that a reliable and practical measurement of systemic baclofen levels has a useful role in clinical practice, particularly for the patient with neurogenic bladder and potential renal insufficiency.

Administration, Oral↗
PubMed1992

Patterns of immunoglobulin G subclass reactivity to HIV-1 envelope peptides in children born to HIV-1-infected mothers.

OBJECTIVE: To analyse the pattern of immunoglobulin (Ig) G subclasses specific for HIV-1 envelope peptides in sera from HIV-1-infected mothers and their newborns. We sought to determine whether there was a selective transfer of antibodies from mother to child, and to establish diagnostic or prognostic properties by analysing HIV-1 peptide-specific IgG isotypes. DESIGN AND METHODS: Parallel sera from 12 HIV-1-infected mothers and their newborn children were analysed for IgG subclass responses to six HIV-1 envelope peptides by enzyme-linked immunosorbent assay. Levels of IgG were compared with levels of IgG1 and IgG3 to an immunodominant gp41 peptide in children's sera obtained during the first months of life. In a longitudinal study of 16 children born to HIV-1-seropositive mothers, of whom 11 were infected, the IgG1 and IgG3 responses to peptides representing an immunodominant epitope of gp41 and the principal neutralizing determinant of the gp120 V3 region were analysed. RESULTS: IgG1 and IgG3 were found to constitute the predominant peptide-specific antibody responses. A parallel distribution of IgG subclass reactivity was seen in maternal and paediatric sera. There was no evidence of selective antibody transfer. Comparable levels of IgG and IgG1 to the immunodominant peptide were seen in infected and uninfected children, while the IgG3 had disappeared in the majority of uninfected children. A decrease in peptide-specific IgG1 and IgG3 levels was observed in sequential sera from uninfected children, although the kinetic profile varied. Sera from infected children showed de novo synthesis of IgG1 and/or IgG3 binding to the selected HIV-1 peptides. Most children with rapid disease progression failed to produce IgG1 and/or IgG3 to the V3 peptide. CONCLUSION: Analysis of IgG subclass kinetics to selected HIV-1 peptides might be a useful additional diagnostic and prognostic tool in evaluating HIV-1 infection in children born to seropositive mothers.

Adult↗
PubMed1992

Physical training in patients with congestive heart failure.

Multiple compensatory mechanisms operate to preserve exercise tolerance in patients with left ventricular failure. Exercise capacity of most patients with chronic heart failure is limited by dyspnea or fatigue, or both. Maximal stress testing with direct assessment of peak O2 uptake is an essential measurement in planning exercise conditioning programs, which are now attracting patients with chronic heart failure. The biochemical and histologic patterns of skeletal muscle changes seen in chronic heart failure patients are consistent with the effects of long-term exercise deconditioning in normal subjects. Recent studies have suggested beneficial effects of training in subjects with moderate or even severe left ventricular dysfunction by showing increased exercise tolerance or peak O2 consumption, anaerobic threshold, peak leg blood flow, peak central arteriovenous oxygen difference and decreased lactate accumulation. However, a number of questions remain unanswered. Exercise training for the treatment of chronic heart failure should be determined on an individual basis and used with caution.

Exercise↗
PubMed1992

Monoclonal antibodies to human low density lipoprotein identify distinct areas on apolipoprotein B-100 relevant to the low density lipoprotein-receptor interaction.

We have characterized the epitopes for ten murine monoclonal antibodies (Mabs) to human low density lipoprotein (LDL) and studied their ability to interfere with the LDL-receptor interaction. The epitopes for the antibodies were defined by using the following approaches: 1) interaction with apoB-48; 2) interaction with apoB-100 thrombolytic fragments; and 3) interaction with beta-galactosidase-apoB fusion proteins spanning different areas of the apoB-100 sequence. The results obtained are consistent with the following map of epitopes: Mab 6E, amino acids (aa) 1-1297, Mabs 5A and 6B, aa 1480-1693, Mabs 2A, 7A, 3B, and 4B, aa 2152-2377, Mabs 8A and 9A, aa 2657-3248 and 3H, aa 4082-4306. Four Mabs (2A, 5A, 7A, and 9A) whose epitopes are located in three different areas of apoB, dramatically reduced (up to 95%) the LDL-receptor interaction on cultured human fibroblasts; Fab fragments were as effective as the whole antibodies. Mab 3H, on the other hand, increased LDL binding up to threefold. These findings are consistent with the hypothesis that several areas of apoB-100 are involved independently or in concert in modulating the apoprotein B conformation required for interaction with the LDL receptor.

Antibodies, Monoclonal↗
PubMed1992

Middle and long-term results of flexion osteotomy for avascular necrosis of the femoral head.

The authors present the results of 19 flexion osteotomies performed in cases of avascular necrosis of the femoral head and followed up after an average of 8 1/2 years. Significant clinical improvement was achieved in 85% of the patients. The radiographic picture is not quite as positive, but only 26% of the patients developed severe degenerative arthritis. The authors therefore consider this technique to be a valid alternative to immediate prosthetic replacement in selected patients.

Adult↗
PubMed1992

[Seminal vesicles: echographic findings in 244 subjects. Evaluation of anatomic data and correlations with pathologic prostatic-vesicular parameters].

Over a 2-year period (1989-90), about 400 cases were examined (out of nearly 2,500 US examinations of the prostate), 244 of which had subsequent bioptic, surgical or autoptic confirmation. This paper reports the anatomic, clinical and pathologic data relative to the seminal vesicles of 244 subjects who underwent transrectal US of the prostate for different clinical indications. Our biometric values were slightly different from those reported in literature, the latter being based on autoptic findings. Agenesis and monolateral ectopia were confirmed to be extremely rare: 4 cases only (1.6%) in our series. A typical finding was the nearly perfect symmetry; in size and structure, of the two seminal vesicles in the same subject; as a matter of fact, a loco-regional pathologic condition was detected in all the patients (14) with asymmetry. A hundred per cent agreement was observed between the US patterns of the seminal vesicles and the prostatic patterns in case of acute/subacute prostatic inflammation involving also the 2 glands: this parameter can be used to follow the clinical course of the inflammatory process.

Adult↗
PubMed1992

Ovulation induction with human menopausal gonadotropin versus follicle-stimulating hormone after pituitary suppression by gonadotropin releasing hormone agonist in polycystic ovary disease. A cross-over study.

Ten patients with polycystic ovary disease (PCOD) had ovulation induction after pituitary suppression by gonadotropin releasing hormone agonist (GnRHa) with GnRHa plus pure follicle-stimulating hormone (FSH) or plus human menopausal gonadotropin (hMG). Duration of the stimulation period and gonadotropin doses were superimposable. A multifollicular response was observed in both treatments. Bioassay and radioimmunoassay of luteinizing hormone, androstanedione and testosterone plasma levels were higher in hMG cycles compared to FSH-treated cycles. No differences was found in FSH and estradiol (E2) plasma concentrations, whereas in hMG-treated cycles the E2/number of follicles and E2/ovarian volume ratios were greater than in the FSH-treated cycles. Clinical results in terms of percentages of ovulation and pregnancies were the same in the two protocols. We conclude that the presence of luteinizing hormone in induction of ovulation in patients with PCOD does not seem to influence follicular recruitment and development, but it may have a role in the enhancement of steroid production.

Adult↗
PubMed1992

Inappropriate emergency test ordering in a general hospital: preliminary reports.

An assessment was made on emergency laboratory test ordering at Udine General Hospital (Italy) to investigate the reasons for the excessive number of requested tests. All the orders for emergency laboratory tests during one week in June 1990 were studied. For each test the time of the order was recorded for every day of the week. The most important aspect of our investigation is the distribution of the orders during the day: in fact, test orders reached two peaks, the upper between 7 and 11 a.m., and the lower between 3 and 6 p.m. The analysis of the record cards showed that 42% of the orders were inappropriate. These preliminary findings were very useful in making the consensus on a Quality Assurance program easier, to improve the use of the Emergency Laboratory by doctors and nurses. Some preliminary results in the Emergency Medicine Department confirmed the validity of this program.

Clinical Laboratory Techniques↗
PubMed1992

Allozyme analysis of Trichinella isolates from various host species and geographical regions.

Allozyme analysis was carried out on 152 Trichinella isolates from synanthropic and wild animals and from humans; the isolates were collected from 5 continents. The analysis, involving 27 enzymes, revealed the presence of 8 distinct gene pools, termed T1-T8. Four of the genetic groups represent the 4 previously proposed species: Trichinella spiralis sensu stricto (T1), Trichinella nativa (T2), Trichinella nelsoni (T7), and Trichinella pseudospiralis (T4). The other 4, T3, T5, T6, and T8 are distinct from previously described species. The absence of allozymic hybrid patterns among even sympatric groups indicates a lack of gene flow among the groups. Principal component analysis and the unweighted pair group method of analysis were used to assemble allozyme patterns of the 152 isolates into discrete groups and to show their relative relationships. Both analyses indicated the presence of 8 primary clusters that correlated with the gene pools revealed by direct allozyme profile analysis. The absence of evidence of gene flow among the gene pools and the high level of allozymic differentiation between the cluster groups support the concept that the genus Trichinella is composed of several sibling species.

Animals↗
PubMed1992

Biological characterization of Trichinella isolates from various host species and geographical regions.

Forty isolates of Trichinella collected from 5 continents were compared for 7 biological characters: newborn larvae produced per female worm cultured in vitro at the seventh, eighth, and ninth day postinfection, host muscle nurse cell development time, reproductive capacity index in rats and chickens, and resistance of muscle larvae to freezing. The isolates also were compared by analyses of an environmental character of the location from which they were isolated: the isotherms for January and July. By factorial analysis of correspondence of the biological and environmental data, the 40 isolates were grouped into 8 gene pools (T1-T8). The environmental temperature-related distribution was more evident for the sylvatic isolates (T2, T3, T5, T6, T7, T8), than for T1, which was isolated from domestic pigs, and for T4, a bird-adapted, nonencapsulating genetic type. The 8 biological groups correlated closely with the 8 gene pools previously identified on the basis of allozyme analysis. These results support the concept that the genus Trichinella is composed of at least 5 distinct gene pools or sibling species: Trichinella spiralis sensu stricto (T1), Trichinella nativa (T2), Trichinella sp. (T3), Trichinella pseudospiralis (T4), and Trichinella nelsoni (T7), and 3 other groups of uncertain taxonomic status (i.e., T5, T6, and T8).

Animals↗
PubMed1992

Lack of association between maternal antibodies to V3 loop peptides and maternal-infant HIV-1 transmission.

We investigated the association between maternal antibodies to HIV-1 peptides in pregnant women and the acquisition of HIV-1 infection by their offspring. Pregnant HIV-1-infected Haitian women were tested for the presence of antibodies against peptides of 14-17 amino acid length from the V3 loop region of strains IIIb and MN. Antibody testing was performed in two separate laboratories by enzyme-linked immunosorbent assay (ELISA). Peptides from four regions of the V3 loop were synthesized in several different laboratories and the purity confirmed by high performance liquid chromatography (HPLC). The mothers of infants who acquired HIV-1 infections did not differ significantly from the mothers of uninfected infants in the prevalence or concentration of antibodies to any of the 15 peptides evaluated. Additional studies are indicated to determine if neutralizing antibodies or other immunologic parameters are associated with maternal-infant HIV-1 transmission.

Amino Acid Sequence↗