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Biomedical subjects

M Botto

Publications and source records attributed to M Botto.

At least 55 records · Page 3Linked to original sources
PubMed1996

Interferon augments PML and PML/RAR alpha expression in normal myeloid and acute promyelocytic cells and cooperates with all-trans retinoic acid to induce maturation of a retinoid-resistant promyelocytic cell line.

The PML gene is fused to the retinoic acid receptor alpha gene (RAR alpha) in the acute promyelocytic leukemia (APL) 15; 17 translocation. PML is expressed in diverse tissues and cell lines and localized in the nucleus with a typical speckled pattern. In the bone marrow, it is preferentially expressed in myeloid cells. PML appears to be transcriptionally regulated by class I and II interferons, which raises the possibility that interferons modulate the function and growth and differentiation potential of normal myeloid cells and precursors by activating PML-dependent pathways. Similarly, interferons could act on APL cells, alone or in combination with all-trans retinoic acid (RA), especially if the PML/RAR alpha fusion transcript that results from the t(15; 17) is induced by interferon. We report here that PML is expressed at low levels or not expressed in normal circulating human monocytes, lymphocytes, and polymorphonucleate cells, but is markedly induced by interferon; that PML and PML/RAR alpha expression is augmented by interferon in the NB4 APL cell line, which carries the t(15; 17), and in APL blasts from patients; that interferon inhibits growth and survival of NB4 APL cells in cooperation with RA; that interferons alone have minimal maturation effect on NB4 cells; and, finally, that interferon gamma, but not alpha or beta, induces maturation and growth suppression of NB4 cells with de novo retinoid resistance, and partially restores RA response.

Cell Differentiation↗
PubMed1996

Extrahepatic secreted complement C3 contributes to circulating C3 levels in humans.

The majority of complement protein C3 is synthesized by the liver, but many other cell types produce small amounts of functionally active C3. The overall contribution of such extrahepatic C3 production to the total circulating C3 level is unknown. Bone marrow and extrahepatic C3 productions were quantified in bone marrow transplant (BMT) and liver transplant (LT) recipients, respectively, where a mismatch for the C3 allotypes distinguished by the mAb HAV 4-1 had occurred. In the BMT group, donor-derived C3 was detected by ELISA and immunoblotting techniques. It contributed to 0.1 to 2.6% of the total circulating C3 during the immediate post-BMT period in response to inflammatory stimuli. Cell culture and immunostaining techniques demonstrated that monocytes were the source of the C3. By 6 wk following BMT, donor-derived C3 levels had decreased to below the detection limit of the assays. By contrast in the LT group, total extrahepatic C3 levels were higher (3.1-5.7% of the total circulating C3) and remained stable for up to 1 yr post-LT. This study demonstrates that extrahepatic derived C3 forms a larger proportion of the circulating C3 levels than was considered previously and that in the resting state, most of this extrahepatically derived C3 comes from nonmyeloid sources. In addition, monocytes, which in the resting state contribute negligible amounts of C3, have the potential when stimulated to contribute significantly to the total systemic C3 pool. These findings highlight the importance of locally secreted complement proteins.

Antibodies, Monoclonal↗
PubMed1996

Organ-specific contribution to circulating C7 levels by the bone marrow and liver in humans.

Many cells types can produce complement component C7, although the major site of C7 synthesis is unknown. Conversion from recipient to donor allotype following organ transplantation has demonstrated the synthetic sites of several complement proteins, but in the case of C7 this was not possible until recently. A novel C7 polymorphism (C7 M/N) has been described based on the reactivity with the monoclonal antibody WU 4-15 which identifies in allotype of C7 (C7 M). Bone marrow and hepatic C7 production was quantified in bone marrow transplant and liver transplant recipients, respectively, where a mismatch for the C7 allotypes distinguished by the monoclonal antibody had occurred. In the bone marrow transplant group, one informative transplant was identified and donor-derived C7 was detected by enzyme-linked immunosorbent assay. It contributed to 18-27% of the total circulating C7 during the post-transplant phase and was increased during episodes of inflammation. In the liver transplant group, the hepatic contribution to the C7 levels were 30% and 52%, respectively, in two patients identified prospectively. A further three informative liver transplant patients were identified retrospectively and in these individuals, 56-62% of the circulating C7 was liver-derived. This study demonstrates that the majority of the circulating C7 is derived from the liver and bone marrow with a lesser contribution from other sources. These findings provide further support for the concept that locally secreted complement proteins have an important role in inflammation.

Base Sequence↗
PubMed1996

Fc gamma RIIa polymorphism in systemic lupus erythematosus (SLE): no association with disease.

An allotypic variant of Fc gamma RIIa, Fc gamma RIIa-HR (Fc gamma RIIa-R131), has been shown in vitro to reduce the capacity of phagocytic cells to bind and internalize IgG-containing immune complexes. Our aim was to determine whether this allotypic variant was associated with susceptibility to SLE and the development of lupus nephritis, as previous studies have suggested. Fc gamma RIIA genotype analysis was performed by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in 215 Caucasoid, 70 Afro-Caribbean, and 46 Chinese patients with SLE, and in 259,77 and 49 ethnically matched controls, respectively. Distribution of Fc gamma RIIa genotypes between the patients and ethnically matched controls was not significantly different in the three populations studied. No association between the Fc gamma RIIa-HR allotype and nephritis was found. Our results suggest that the Fc gamma RIIa-HR allotype is not a major factor predisposing to the development of SLE, or to lupus nephritis.

Base Sequence↗
PubMed1996

The mouse C1q genes are clustered on chromosome 4 and show conservation of gene organization.

Mouse complement component C1q is a serum glycoprotein which consists of six A chains, six B chains and six C chains. The three polypeptides are 223, 228, and 217 residues long, respectively, and are encoded by three genes. DNA probes for mouse C1q A, B, and C chains were hybridized to Southern blots of DNA obtained from various inbred mouse strains. On the basis of fragment length polymorphisms, two different alleles of each of the genes could be identified. The distribution of these alleles was determined in the BXD and LXPL recombinant inbred strain series. Comparison with previously reported strain distribution patterns shows that the genes encoding mouse C1q map to the same locus on distal chromosome 4. Overlapping clones spanning the entire gene cluster of C1q were isolated from genomic libraries using specific cDNA probes. The three genes C1qA, C1qB, and C1qC are closely arranged on a 19 kilobase stretch of DNA in the 5' to 3' orientation A-C-B. Each gene consists of two exons separated by one intron. Sequence comparison of C1q from three different species have shown that the B chains have the strongest similarity. Southern blot analysis of chromosomal DNA from 14 vertebrate species demonstrated highest similarity between the C1qB genes, followed by C1qC and finally C1qA.

Amino Acid Sequence↗
PubMed1995

Complement component C3: molecular basis of the C3*S025 variant and evidence for molecular heterogeneity of other variants.

Complement component 3 (C3) is the central molecule of the complement system. It displays a number of polymorphic variants with, as yet, unclear functional consequences. We have investigated a number of rare C3 variants by PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) analysis and could identify the molecular basis of a C3*S025 variant. The decreased electrophoretic mobility of this protein is caused by the exchange of a neutral serine residue to an arginine residue (positively charged). This exchange is unlikely to have functional consequences as it maps to the C-terminus of the alpha-chain. C3 variants appear to have originated from various independent mutations as we could not detect this mutation in different allotypes.

Base Sequence↗
PubMed1994

Cyclosporin in Behçet's disease: results in 16 patients after 24 months of therapy.

The aim of this study was to evaluate the usefulness of cyclosporin in Behçet's disease. Sixteen subjects (10 males and 6 females; mean age 25.2 years) affected by the complete type of Behçet's syndrome received 5 mg/kg/day of cyclosporin for 24 months. A marked improvement of the symptoms was observed after three months of therapy. Within 6 to 12 months of treatment 14 of the 16 patients obtained a complete clinical remission. Biochemical and immunological parameters were controlled periodically to evaluate the clinical response and the possible side-effects. Two patients dropped out of the study because of anaemia and renal dysfunction, which returned to normal when cyclosporin was withdrawn. Our results confirm the efficacy of cyclosporin in the treatment of Behçet's disease.

Adult↗
PubMed1994

C3 nephritic factor and SLE: report of four cases and review of the literature.

We present four patients with C3 nephritic factor associated with partial lipodystrophy and/or mesangiocapillary glomerulonephritis type II. Each of these patients subsequently developed features of SLE, with an onset between 2 and 24 years after the development of the lipodystrophy or glomerulonephritis. All four patients had antinuclear antibodies and three of the four had anti-Ro antibodies. These patients bring to six the number of reported cases of this association. Possible explanations for the link between these two conditions are discussed.

Adult↗
PubMed1993

Seronegative spondyloarthropathy associated with megarectum.

In this report we describe a case of a 19-year-old man with a two-year history of polyarthritis affecting the lower limbs and dactylitis of the toes. His clinical picture fulfilled the new European diagnostic criteria for spondyloarthropathies. Systemic examination revealed a big mass in the left iliac fossa that was found to be due to an acquired functional megacolon. Complete remission of the joint involvement was obtained by treating the bowel disease.

Adolescent↗
PubMed1993

Hereditary deficiency of C3 in animals and humans.

Inherited deficiency of complement C3 has been described in guinea pigs, dogs and 20 humans. Homozygous deficiency of C3 is associated with recurrent pyogenic infections by encapsulated bacteria, especially H. influenzae, S. pneumoniae and N. meningitidis. In dogs and humans there is also an association with development of glomerulonephritis of the mesangiocapillary type. Some patients also develop transient erythematous rashes in association with pyogenic infections, with histology showing predominantly neutrophil infiltration and small vessel vasculitis. Studies of antibody responses, mainly in experimental animals have shown impaired primary and secondary responses to both thymus-dependent and -independent antigens at low immunizing doses, with a reduced switch from IgM to IgG production. The molecular basis of C3 deficiency has been established in two humans with C3 deficiency. In one it was due to a splice junction mutation and in another, to a partial gene deletion. These mutations are not compatible with the production of functional C3 in any tissue. Such patients with absolute C3 deficiency are a valid model for understanding the physiological role of C3 in vivo.

Animals↗
PubMed1993

[Liver involvement in systemic lupus erythematosus].

From the revision of the literature it emerges that liver disease in systemic lupus erythematosus (SLE) has been reported in 8 to 23% of the patients and usually is of modest clinical relevance. The incidence of liver abnormalities in 86 patients affected by SLE (9 men and 77 women, mean age 42.1 +/- 13.1 years) was therefore analysed. In our study, liver involvement was defined when at least two abnormal liver function tests in two different occasions were detected. Evidence of liver disease was found in 20 of our patients (23.2%); in 6 cases liver abnormalities were not directly caused by SLE: in 3 subjects the abnormalities found were induced by drugs, in 2 patients by infection and in the last one by fatty liver. In the remaining 14 cases (16.2%), whose hepatic involvement was really due to SLE, a higher frequency of positivity for anti-ds-DNA antibodies than in the other patients was observed (92.8% and 51.3% respectively in the two groups, p < 0.05). As not reported previously, these data suggest that liver disease is a prerogative feature of severe SLE. From our casistic in only 1 case the hepatic injury was the onset clinical manifestation of the disease and was clinically relevant as it was diagnosed as chronic active hepatitis. These observations therefore offer the opportunity to discuss the relationship between SLE and autoimmune hepatitis.

Adolescent↗
PubMed1993

[Symmetric multiple lipomatosis with Charcot's joint and neuropathic ulcer. Description of a clinical case].

Multiple symmetric lipomatosis (MSL) (or Madelung's disease or Launois-Bensaude syndrome) is a rare inherited disease clinically characterized by a massive development of large symmetric unencapsulated lipomas on the subcutaneous tissue of face, neck, trunk and arms, resulting in a grotesque aspect of the patient. Less frequently the accumulation of excessive fatty tissue can spread deeply to the superficial fascia. Peripheral neuropathy, macrocytic anemia and chronic hepatopathy have been reported to cohesist. Macrocytic anaemia and chronic hepatopathy are probably secondary to high alcohol consumption, that is frequently associated. MSL, that was first described by Sir Benjamin Brodie in 1846, affects mainly the men (ratio man/woman 30:1), with an incidence in Mediterranean area of 1:25.000 men; the ages at onset range from 20 to 50 years. It is not known yet the pathway of inheritance and the molecular basis of the genetic defect responsible for the development of fat accumulation. It has been postulated a defective lipolytic response to catecholamines; this altered response could be due to an abnormal amount or a defective function of Gs-protein, the coupler between beta-adrenergic receptors on the surface of adipocytes and adenylate cyclase, or, alternatively, the defect could be in the catalytic unit of adenylate cyclase. The number and function of alpha- and beta-adrenergic receptors and the lipolytic response to cAMP (the second messenger) are normal. Recently it has been hypothesized that the defective lipolysis is due to a disorder in the mitochondria of brown fat, whose distribution is similar to the peculiar position of the lipomas in this pathology; the brown fat, unlike white adipose tissue, has abundant mitochondria. The alcohol abuse, frequently present in these subjects, might facilitate the clinical expression of the molecular defect. The therapy of lipomas is essentially surgical, but this approach is not easy, because the lipomas are not capsulated and extremely vascularized. Moreover the surgical excision is not always a successful treatment for the lipomas as they frequently recurrent after a short period from the exeresis. In this report we describe a 59-years old white man, alcohol abuser, with a typical clinical picture of MSL, developed when he was 37 years old. The patient presented multiple lipomas around the shoulders, face, neck and arms, that had been surgically excised eight times. Magnetic resonance imaging showed the presence of fat deposits also in the mediastinum, that caused a tracheal compression. Hepatic cirrhosis and serious side effects from peripheral neuropathy, represented by Charcot's joint and neuropathic ulcer on the sole foot were observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Arthropathy, Neurogenic↗
PubMed1993

[Native anti-DNA antibodies and the synovial fluid. A report of a problematic clinical case].

The authors report the unusual case of a 30-years-old woman affected by bilateral gonarthritis with anti-ds DNA antibodies at higher level in synovial fluid than in serum. This finding, and the presence of an intensive infiltration of polyclonal plasma cells in the synovial membrane, studied by biopsy, lead to suppose a local production of autoantibodies with a probable pathogenetic role.

Adult↗
PubMed1992

Biosynthesis and secretion of complement component (C3) by activated human polymorphonuclear leukocytes.

We tested the hypothesis that human polymorphonuclear leukocytes (PMN), bearing complement receptors CR1 and CR3, might also synthesize C3, particularly when activated by LPS or cytokines. Northern blot analysis of total RNA, obtained from purified PMN stimulated overnight with LPS or cytokines (IFN-gamma, TNF-alpha, and IL-1) showed the 5.3-kb RNA transcript reported for C3 in hepatocytes and monocytes. No transcripts for C4 and factor B were detected. Time course studies of C3 mRNA expression in PMN treated with LPS or TNF-alpha demonstrated a steady increase with a plateau at 24 h that correlated with secretion of C3, determined by ELISA. In contrast, IFN-gamma and IL-1 induced a transient increase in C3 transcript with a peak around 8 h after stimulation, which was not reflected in an increased rate of C3 secretion. The content of C3 protein in PMN culture media, measured by ELISA, was about 4 ng/ml/10(7) cells after overnight stimulation with LPS or TNF-alpha. A very small amount of C3 (about 0.7 ng/ml/10(7) cells) was detected in supernatants from unstimulated and IFN-gamma- or IL-1-induced PMN. Immunoprecipitation with a polyclonal anti-human C3, followed by SDS-PAGE analysis, from [35S]methionine labeled PMN, revealed the presence in culture supernatants of three major bands at 185, 115 and 70 kDa, corresponding to pro-C3, alpha and beta chains, respectively. Analysis of [14C]methylamine incorporation and of autolytic cleavage showed that the C3 produced in tissue culture by PMN contained an intact thiolester bond. The capacity of PMN to secrete functional C3 in response to LPS and TNF-alpha might be an important mechanism of host defense at sites of inflammation.

Base Sequence↗
PubMed1992

Homozygous hereditary C3 deficiency due to a partial gene deletion.

The molecular mechanism of C3 deficiency in an Afrikaans patient with recurrent pyogenic infections was studied. Restriction enzyme analysis showed a gene deletion of 800 base pairs (bp) mapping to the alpha chain of C3. Amplification of genomic DNA, using the PCR, demonstrated that the deletion included exons 22 and 23 of the C3 gene. Truncated mRNA was shown in an Epstein-Barr virus-transformed B-cell line by PCR amplification of first-strand cDNA. A consequence of this deletion was that the RNA transcribed 3' to the deletion was out of frame, resulting in formation of a stop codon 19 bp downstream from the deletion. The molecular basis of the deletion was compatible with homologous recombination between two Alu sequences located in introns 21 and 23. An unrelated nonconsanguineous relative and two of a sample of 174 Afrikaans-speaking individuals were heterozygous carriers of the same gene deletion. The wide prevalence of this null allele in this population is probably due to the effects of a small founder population. The presence of this deletion in the C3 gene is not compatible with production of any functional C3, supporting the idea that study of such patients offers a valid model for understanding physiological activities of C3 in vivo in humans.

Base Sequence↗
PubMed1992

[Jaccoud's postrheumatic arthritis. A clinical case report].

The authors describe a case of Jaccoud's arthropathy, a very rare disease of unknown pathogenesis, that can develop in patients after repeated attacks of rheumatic fever. Clinical pictures with analogous features can be found associated with many other pathological processes, such as connective tissue diseases or cancers. The case presented here is interesting for the diagnostic and therapeutic mistakes made, probably because it is an illness very little known and with ambiguous clinical features.

Arthritis, Reactive↗
PubMed1990

Molecular basis of polymorphisms of human complement component C3.

C3 exhibits two common allotypic variants that may be separated by gel electrophoresis and are called C3 fast (C3 F) and C3 slow (C3 S). C3 F, the less common variant, occurs at appreciable frequencies only in Caucasoid populations (gene frequency = 0.20). An increased prevalence of the C3 F allele has been reported in patients with partial lipodystrophy, IgA nephropathy, and Indian childhood hepatic cirrhosis. Studies of the genomic organization of the human C3 gene led to the identification of a single change (C to G) between C3 S and C3 F at nucleotide 364 in exon 3. This leads, at the translation level, to the substitution of an arginine residue (positively charged) in C3 S for a glycine residue (neutral) in C3 F. This substitution results in a polymorphic restriction site for the enzyme HhaI. The resulting restriction fragment length polymorphism (RFLP) was investigated using genomic DNA, amplified using the polymerase chain reaction; there was absolute concordance between the genomic polymorphism and the distribution of C3 S and C3 F in 50 normal subjects. The molecular basis of a second structural polymorphism, defined by the monoclonal antibody HAV 4-1, was also characterized. The polymorphic determinant was identified at codon 314 in the exon 9 of the beta chain where a leucine residue (HAV 4-1+) is substituted for a proline residue (HAV 4-1-). Identification of the amino acid sequences of these polymorphic variants will facilitate characterization of possible functional differences between different allotypes of C3. Three RFLPs (BamHI, EcoRI, and SstI) were located to introns in the C3 gene. There was no allelic association between these three RFLPs, or between the RFLPs and the C3 F/S polymorphic site. Genetic equilibration of these polymorphisms has occurred within a gene of 41 kb.

Antibodies, Monoclonal↗