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P Figueroa

Publications and source records attributed to P Figueroa.

At least 19 recordsLinked to original sources
PubMed2026

Ovarian expression and function of neuropeptide systems in teleosts and anurans.

The hypothalamic-pituitary-gonadal axis regulates reproduction, sexual maturation, and spawning behaviours. Its evolutionary origins trace back to primitive jawless fish and has been well characterized in teleosts. Recent advances in multi-species genome sequencing, annotation, and experimental approaches for identifying and characterizing key regulators have advanced understanding of neuroendocrine regulation in teleost reproduction, reshaping existing models. Early studies in amphibians established that steroids are critical regulators of final oocyte maturation. Subsequent work in anurans revealed complex interactions among theca cells, follicular cells, and oocytes, supporting a three-cell model in which oocytes contribute to their own steroidogenic environment, challenging the traditional two-cell view of ovarian steroidogenesis. In teleosts, however, direct evidence that oocytes support steroid precursor delivery to theca and follicular cells is limited, and whether a comparable three-cell model applies remains an open hypothesis. Across both taxa, the roles of locally produced neuropeptides in coordinating interactions among theca cells, follicular cells, and oocytes remain largely uncharacterized. Here, we provide a short review of the localization and potential autocrine/paracrine functions of neuropeptides in teleost and amphibian ovaries and discuss existing knowledge gaps. We identify opportunities to leverage detailed localization studies that map neuropeptides to specific ovarian cell types and developmental stages, and discuss how integrating traditional and emerging experimental approaches can advance comparative studies in ovarian endocrinology. This work will improve our understanding of reproductive regulation in fishes and frogs, with applications in captive breeding, aquaculture, and endocrine disruption research.

Autocrine↗
PubMed2001

Three different genes encode the iron-sulfur subunit of succinate dehydrogenase in Arabidopsis thaliana.

The iron-sulfur protein is an essential component of mitochondrial complex II (succinate dehydrogenase, SDH), which is a functional enzyme of both the citric acid cycle and the respiratory electron transport chain. This protein is encoded by a single-copy nuclear gene in mammals and fungi and by a mitochondrial gene in Rhodophyta and the protist Reclinomonas americana. In Arabidopsis thaliana, the homologous protein is now found to be encoded by three nuclear genes. Two genes (sdh2-1 and sdh2-2) likely arose from a relatively recent duplication event since they have similar structures, encode nearly identical proteins and show similar expression patterns. Both genes are interrupted by a single intron located at a conserved position. Expression was detected in all tissues analysed, with the highest steady-state mRNA levels found in flowers and inflorescences. In contrast, the third gene (sdh2-3) is interrupted by 4 introns, is expressed at a low level, and encodes a SDH2-3 protein which is only 67% similar to SDH2-1 and SDH2-2 and has a different N-terminal presequence. Interestingly, the proteins encoded by these three genes are probably functional because they are highly conserved compared with their homologues in other organisms. These proteins contain the cysteine motifs involved in binding the three iron-sulfur clusters essential for electron transport. Furthermore, the three polypeptides are found to be imported into isolated plant mitochondria.

Amino Acid Sequence↗
PubMed2000

The nuclear-encoded SDH2-RPS14 precursor is proteolytically processed between SDH2 and RPS14 to generate maize mitochondrial RPS14.

In maize, the functional gene encoding mitochondrial ribosomal protein S14 (rps14) has been translocated to the nucleus where it became integrated between both exons of a gene encoding the iron-sulfur subunit of succinate dehydrogenase (sdh2). Two transcripts are generated from this locus by alternative splicing. One transcript encodes a precursor for a functional SDH2 protein, while the second transcript encodes a chimeric SDH2(t)-RPS14 precursor protein. In this paper we show that the same mitochondrial targeting presequence is able to direct the import of both precursors into isolated mitochondria and is removed during import. This processing event generates a 28 kDa protein from the SDH2 precursor, which corresponds to the iron-sulfur subunit of respiratory complex II present in maize mitochondria. In addition to cleavage of the presequence, the chimeric precursor undergoes proteolytical processing between SDH2 and RPS14. This processing generates RPS14, which is found assembled into mitochondrial ribosomes, and a truncated SDH2 protein which is degraded. Therefore, our results support a role of the SDH2 domain in the chimeric precursor only in providing a mitochondrial targeting function for RPS14.

Amino Acid Sequence↗
PubMed2000

An unusual presentation of dermatomyositis: the type Wong variant revisited.

We describe a 53-year-old white woman with dermatomyositis (DM) who had additional clinical findings of pityriasis rubra pilaris (type Wong dermatomyositis) with histopathologic features of both pityriasis rubra pilaris (PRP) and porokeratosis. Type Wong dermatomyositis was originally described in 11 patients by Wong in 1969 and has been reported in 5 additional patients. This is a rarely described phenomenon in which patients with DM develop cutaneous hyperkeratotic lesions that resemble PRP and histologically show follicular hyperkeratosis and hair follicle destruction. Arrector pilorum muscles also show degenerative findings and myositis. We believe that this is the first reported case of a patient with type Wong DM who also has clinical and histologic features suggestive of porokeratosis. This is important because of the association of adult-onset dermatomyositis with internal malignancy and the well-documented association of porokeratosis with immunosuppression. These clinical and histologic findings serve as markers for malignancy in patients with DM. These patients warrant a complete review of systems and investigation for age-appropriate neoplasms as well as close long-term follow-up by dermatologists to ensure that these cutaneous eruptions are not overlooked.

Dermatomyositis↗
PubMed2000

Cell vacuolation, a manifestation of the El tor hemolysin of Vibrio cholerae.

Culture supernatants of nontoxigenic nonepidemic clinical strains of Vibrio cholerae belonging to diverse serogroups were found to induce vacuolation of nonconfluent HeLa cells. The vacuoles became prominent 18 h after introduction of culture supernatant, and vacuolated cells survived for 48 h and then died. Only a fraction of the vacuolated cells took up neutral red dye, implying that there were differences in the vacuolar microenvironment. Further tests showed that the factor responsible for vacuolation was heat labile and proteinaceous. Vacuolating activity was completely neutralized by antibody to hemolysin of V. cholerae but not by antibody to vacuolating cytotoxin of Helicobacter pylori. Partial purification of the vacuolating factor led to elution of fractions, which showed both hemolytic and vacuolating activity. PCR amplification and cloning of the hemolysin structural gene (hlyA) into Escherichia coli DH5alpha led to isolation of clones producing cell vacuolating factor in a cell-associated form. Further, a null insertion mutation in the hlyA gene of a high-vacuolating-factor-producing strain led to complete abolition of both cell vacuolating and hemolytic activities. These analyses establish vacuolation as a potentially important but previously unrecognized property of V. cholerae El Tor hemolysin.

Animals↗
PubMed2000

Can granuloma annulare evolve into cutaneous sarcoidosis?

We report the unique case of a 50-year-old African American female with pulmonary sarcoidosis who presented with a new ichthyosiform eruption symmetrically located on the anterior shins and surrounded by red, translucent, intradermal papules. A skin biopsy of a new red papule showed features consistent with granuloma annulare (GA) with positive mucin staining, and an older hyperpigmented papule showed classic dermal noncaseating granulomas consistent with sarcoidosis. Recent reports have clearly demonstrated GA occurring in association with sarcoidosis, but this is the first report that suggests that a GA lesion may develop into a sarcoidal granuloma. We propose that GA may act as a precursor lesion to the more mature sarcoidal granuloma. This case further underscores the importance of careful clinicopathologic correlation.

Anti-Inflammatory Agents↗
PubMed1999

The gene for mitochondrial ribosomal protein S14 has been transferred to the nucleus in Arabidopsis thaliana.

The transfer of genetic information from the mitochondrion to the nucleus is thought to be still underway in higher plants. The mitochondrial genome of Arabidopsis thaliana contains only one rps14 pseudogene. In this paper we show that the functional gene encoding mitochondrial ribosomal protein S14 has been translocated to the nucleus. This gene transfer is a recent evolutionary event, which occurred within Cruciferae, probably after the divergence of Arabidopsis and Brassica napus. A 5' extension of the rps14 reading frame encodes a presequence which, in vitro, targets the polypeptide to isolated mitochondria and is cleaved off during or after import. No intron was found at the junction of the targeting presequence with the mitochondrially derived sequence, which are directly connected. By contrast, a 90-bp intron, which is removed by splicing to give a mature poly(A)+ mRNA of 0.9 kb, is located in the 3' non-coding region. To our knowledge, this is the first report of an intron in such a position in a functional transferred gene in higher plants, and suggests that exon shuffling may have been involved in the acquisition of elements necessary for expression in the nucleus. Putative roles of this intron in polyadenylation and enhancement of gene expression are discussed.

Amino Acid Sequence↗
PubMed1999

Transfer of rps14 from the mitochondrion to the nucleus in maize implied integration within a gene encoding the iron-sulphur subunit of succinate dehydrogenase and expression by alternative splicing.

The maize mitochondrial genome does not contain a gene coding for ribosomal protein S14. In this paper we show that the functional rps14 gene was translocated to the nucleus and acquired the signals conferring expression and product targeting to the mitochondrion in a way not previously described. Transferred rps14 was found integrated between both exons of a gene encoding the iron-sulphur subunit of the respiratory complex II (sdh2). Sdh2 exon 1 and rps14 were separated by a typical plant nuclear intron that was spliced to give a mature poly(A)+ mRNA of 1.4 kb. This processed mRNA encoded a chimeric SDH2 (truncated)-RPS14 polypeptide, and we show that this chimeric polypeptide is targeted into isolated plant mitochondria, where it is proteolytically processed in a complex way. An alternative splicing event utilizing the same 5' splice site and a different downstream 3' splice site generated a second mature poly(A)+ mRNA of 1.3 kb that contained both sdh2 exons. This sdh2 transcript encoded an SDH2 polypeptide highly conserved compared with its homologues in other organisms, and it contained the three cysteine-rich clusters that made up the three non-heme iron-sulphur centres responsible for electron transport. To our knowledge, these results constitute the first evidence of alternative splicing playing a role in the expression and targeting of two mitochondrial proteins with different functions from the same gene.

Alternative Splicing↗
PubMed1999

Jamaica's measles elimination experience.

OBJECTIVES: This article describes the effort to eliminate measles from Jamaica and its impact on measles incidence. METHODS: In addition to routine measles vaccination, the Jamaican Ministry of Health implemented a strategy of a 1-time-only catch-up vaccination campaign, conducted in 1991, and periodic follow-up campaigns, the first of which occurred in 1995. RESULTS: Since 1991, despite careful surveillance, no serologically confirmed indigenous cases of measles have occurred in Jamaica. CONCLUSIONS: Measles virus circulation has been interrupted in Jamaica. The Jamaican experience provides further evidence that global measles eradication is achievable.

Adolescent↗
PubMed1999

An infectious mononucleosis-like syndrome induced by minocycline: a third pattern of adverse drug reaction.

A 22-year-old black man developed fever, chills, fatigue, night sweats, tender lymphadenopathy, and a generalized, pruritic, macular eruption 3 weeks after starting minocycline therapy for acne. His illness was also characterized by a palpable spleen tip, marked lower extremity and scrotal edema, and generalized lymphadenopathy. The patient had leukocytosis with a large percentage of atypical lymphocytes on peripheral smear and liver dysfunction. Titers for Epstein-Barr virus, hepatitis B, toxoplasmosis; and cytomegalovirus were all negative. Human immunodeficiency virus-1 viral load and antibodies were also negative. Marked improvement was noted after the discontinuation of minocycline and the use of systemic corticosteroids. With the negative viral serologies, the clinical picture was most consistent with an infectious mononucleosis-like syndrome produced by the minocycline ingestion.

Acne Vulgaris↗
PubMed1998

Plasmapheresis in the treatment of steroid-resistant focal segmental glomerulosclerosis in native kidneys.

A circulating glomerular capillary albumin permeability factor (P(alb)) has been implicated in the pathogenesis of focal segmental glomerulosclerosis (FSGS), which recurs in transplanted kidneys. Plasmapheresis for recurrent FSGS may reduce proteinuria and stabilize renal function if instituted early. We performed six plasmapheresis treatments over 2 weeks in eight patients with a history of steroid-resistant idiopathic FSGS in native kidneys for an average of 12 +/- 2.3 months to determine whether treatment would decrease proteinuria or stabilize renal function. P(alb) was measured before and after plasmapheresis, and patients were followed-up for a mean of 29 +/- 4 months after the development of clinical symptoms. Proteinuria decreased in two of eight treated patients, although only transiently in one of the two. P(alb) improved in one of the two responding patients. Both patients with an improvement in proteinuria had stable renal function at last follow-up. In six of eight patients, there was no improvement in proteinuria despite an improvement in P(alb) (P < 0.0001) after plasmapheresis. At last follow-up, renal function was stable in two of the six nonresponding patients, and four of the six had significant progression of renal disease or were receiving dialysis treatments. These studies suggest that plasmapheresis may diminish proteinuria and stabilize renal function in a small minority of patients with steroid-resistant idiopathic FSGS. However, the lack of a relationship between the removal of the circulating permeability factor and the development of remission in these patients suggests that local factors associated with advanced renal injury or systemic factors unrelated to glomerular permeability play a significant role in determining proteinuria at this late stage of the disease.

Adolescent↗
PubMed1998

Improving sexually transmitted disease management in the private sector: the Jamaica experience.

OBJECTIVES: To improve the quality of sexually transmitted disease (STD) case management in Jamaica by providing comprehensive continuing medical education to private practitioners who manage 60% of all STDs on the island. METHODS: Six half-day STD seminars were presented at 3-4-month intervals and repeated in three separate geographic locations. All Jamaican practitioners received invitations. The subjects were as follows: urethritis, genital ulcer disease, HIV infection, vaginal discharge syndrome, STDs in children and adolescents, and a review seminar. The program effectiveness was evaluated with a written, self-reported pre-test and a telephone post-test that measured changes in clinical management. RESULTS: Six hundred and twenty eight practitioners attended at least one seminar. Comparing pre- versus post-test scores, there were practitioner improvement trends in all four of the general STD management categories: counseling/education (69.8-73.3%; P > 0.05); diagnostics/screening (57.2-71.0%; P= 0.042); treatment (68.3-74.5%; P> 0.05); and knowledge (66.4-83.2%; P= 0.002). Obtaining syphilis serologies during pregnancy rose from 38.3 to 83.8% (P= 0.001), and providing effective treatment for gonorrhea rose from 57.8 to 81.1 % (P= 0.002), but correct responses on treatment for mucopurulent cervicitis at the post-test was a low 32.4%. CONCLUSION: The introduction of continuing medical education for improved STD care targeting private physicians in Jamaica was successful based on high attendance rates and self-reported STD management practices. However, efforts should continue to address the weaknesses found in STD management and counseling and to reach the providers who did not participate. In the global effort to reduce HIV transmission by improving STD care services, continuing education programs that target the private sector can be successful and should be included as a standard activity to improve care and provide a public/private link to STD/HIV control.

Adolescent↗
PubMed1996

Concurrent thrombotic thrombocytopenic purpura and immune thrombocytopenic purpura in an HIV-positive patient: case report and review of the literature.

Immune thrombocytopenic purpura (ITP) and thrombotic thrombocytopenic purpura (TTP) have each been associated with HIV infection. Sequential occurrence of these two diseases with a disease-free interval has been occasionally reported in the literature, whereas simultaneous manifestations of these two diseases have not been described. Here, we report an AIDS patient who was initially diagnosed as having TTP and showed an apparent partial response to plasmapheresis but was found to have a clinical course similar to ITP. Although precise mechanisms for the development of TTP and ITP in these patients are unclear, we offer several hypotheses. It is important to recognize that these two processes may be seen concurrently.

AIDS-Related Opportunistic Infections↗
PubMed1995

Amplification of human papillomavirus types 16 and 18 in invasive cervical cancer.

The distribution and amplification patterns of human papillomavirus were studied in 15 human papillomavirus (HPV) 16- and six HPV18-positive cervical carcinomas by colorimetric in situ hybridization (ISH). The findings were correlated with the viral copy number and status of E1/E2 viral genes in the tumor DNA, as studied by dot blot analysis and the polymerase chain reaction, respectively. The tumors were classified according to the ISH signal into single dot, multidot, diffuse, and mixed patterns. The signal was homogeneously distributed only in single dot tumors and was clearly heterogeneous in tumors with mixed nuclear signal patterns, including both dot and diffuse signals. The single dot pattern predominated in HPV 18-positive tumors (83%), whereas the multidot pattern was most frequent in HPV 16-positive tumors (47%). Diffuse and mixed patterns were noted only in HPV 16-positive tumors (33%). The lowest mean copy of number per cell was observed in single dot tumors (25 +/- 15) with an ascendent trend toward the diffuse signal tumors (2832 +/- 2281). E1/E2 genes were disrupted in 75% of the single/multidot tumors and in none of the diffuse/mixed tumors. These data suggest diffuse signals originate by episomal amplification and dot signals originate by viral integration. Diffuse and dot patterns suggest different mechanisms of viral transformation.

Base Sequence↗
PubMed1990

[Perspectives of liver transplantation in Chile].

After an initial experience with 4 patients who received orthotopic liver transplant (OLT) we analyze the perspectives of establishing liver transplantation programs in Chile. An estimated 100 adult and pediatric patients require OLT a year and no more than 3 centers are required to deal with this and acquire experience with the procedure. A national organization for organ procurement is essential, given the marked difficulties in obtaining cadaver organs at present. Each procedure has an estimated cost of $5 million with 2 more millions in the first year. Thus a program for 15 patients a year may cost $ 100 million, personnel expenses not included.

Adult↗