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Biomedical subjects

R Carlos

Publications and source records attributed to R Carlos.

At least 19 recordsLinked to original sources
PubMed2006

Gastroenterologists utilize the referral for EGD to enhance colon cancer screening more effectively than primary care physicians.

BACKGROUND: Colorectal cancer screening rates among patients with upper gastrointestinal symptoms undergoing oesophagogastroduodenoscopy have not been previously established. We hypothesize that gastroenterologists seize this opportunity more frequently than primary care providers. AIMS: To assess colorectal cancer screening rates at the time of direct access oesophagogastroduodenoscopy and gastrointestinal clinic evaluation for upper gastrointestinal symptoms. To compare rates in the 6 months following the oesophagogastroduodenoscopy in both cohorts of patients. METHODS: Retrospective review. primary care physician group: direct access oesophagogastroduodenoscopy (n = 247) vs. gastrointestinal group (n = 278). Multivariable regression analysis utilized to assess predictors of screening outcome. RESULTS: Colorectal cancer screening at the time of referral was 54%. Among the 243 unscreened patients, an additional 29% in the primary care physician group vs. 59% in the gastrointestinal group completed colorectal cancer screening in 6 months of follow-up. Nearly 60% patients evaluated in gastrointestinal clinic for upper symptoms had documented discussion, and 99% of those patients underwent colonoscopy (P < 0.001). Gastrointestinal consultation increased the probability of colorectal cancer screening completion eightfold (95% CI 3.69-18.96). CONCLUSIONS: At the time of evaluation for upper symptoms, half of patients were not current with colorectal cancer screening recommendations. Referrals for the direct access oesophagogastroduodenoscopy and, more importantly, the gastroenterology consult represent key opportunities for colorectal cancer screening education and improved compliance.

Age Factors↗
PubMed2005

Trismus-pseudocamptodactyly syndrome (Hecht-Beals' syndrome): case report and literature review.

The trismus-pseudocamptodactyly syndrome (TPS) is a rare condition inherited as an autosomal dominant trait with variable expressivity. Clinically the syndrome is characterized by decreased ability to open the mouth and curvature of the fingers at the level of interphalangic joints while attempting dorsiflexion of the wrist (pseudocamptodactyly). A 6-year-old male patient from Guatemala with this syndrome is presented. The surgical treatment consisted of bilateral coronoid amputation to resolve the pseudotrismus. The procedure was successful and the patient achieved normal function.

Abnormalities, Multiple↗
PubMed2004

Clinico-pathological conference 2002.

INTRODUCTION: Six cases are reported, each presented at the 11th Biennial Congress of the International Association of Oral Pathologists as an instructive case for differential diagnosis on the basis of clinical, imaging or histological features. CLINICAL PICTURE: Case diagnoses included a large, possibly intraosseous, myofibroma presenting with an oral mass; Langerhans cell histiocytosis with facial skin lesions; an intraosseous vascular hamartoma of the maxilla with worrying radiological features; an unusual mixed radiolucency of the jaw caused by cemento-ossifying fibroma; an osteosarcoma of the posterior mandible causing a well-defined radiolucency and an intraoral squamous cell carcinoma in a child.

Adolescent↗
PubMed2001

Evaluation of the woman with postmenopausal bleeding: Society of Radiologists in Ultrasound-Sponsored Consensus Conference statement.

OBJECTIVES: A panel of 14 physicians practicing medicine in the United States with expertise in radiology, obstetrics and gynecology, gynecologic oncology, hysteroscopy, epidemiology, and pathology was convened by the Society of Radiologists in Ultrasound to discuss the role of sonography in women with postmenopausal bleeding. Broad objectives of this conference were (1) to advance understanding of the utility of different diagnostic techniques for evaluating the endometrium in women with postmenopausal bleeding; (2) to formulate useful and practical guidelines for evaluation of women with postmenopausal bleeding, specifically as it relates to the use of sonography; and (3) to offer suggestions for future research projects. SETTING: October 24 and 25, 2000, Washington, DC, preceding the annual Society of Radiologists in Ultrasound Advances in Sonography conference. PROCEDURE: Specific questions to the panel included the following: (1) What are the relative effectiveness and cost-effectiveness of using transvaginal sonography versus office (nondirected) endometrial biopsy as the initial examination for a woman with postmenopausal bleeding? (2) What are the sonographic standards for evaluating a woman with postmenopausal bleeding? (3) What are the abnormal sonographic findings in a woman with postmenopausal bleeding? (4) When should saline infusion sonohysterography or hysteroscopy be used in the evaluation of postmenopausal bleeding? (5) Should the diagnostic approach be modified for patients taking hormone replacement medications, tamoxifen, or other selective estrogen receptor modulators? CONCLUSIONS: Consensus recommendations were used to create an algorithm for evaluating women with postmenopausal bleeding. All panelists agreed that because postmenopausal bleeding is the most common presenting symptom of endometrial cancer, when postmenopausal bleeding occurs, clinical evaluation is indicated. The panelists also agreed that either transvaginal sonography or endometrial biopsy could be used safely and effectively as the first diagnostic step. Whether sonography or endometrial biopsy is used initially depends on the physician's assessment of patient risk, the nature of the physician's practice, the availability of high-quality sonography, and patient preference. Similar sensitivities for detecting endometrial carcinoma are reported for transvaginal sonography when an endometrial thickness of greater than 5 mm is considered abnormal and for endometrial biopsy when "sufficient" tissue is obtained. Currently, with respect to mortality, morbidity, and quality-of-life end points, there are insufficient data to comment as to which approach is more effective. The conference concluded by identifying several important unanswered questions and suggestions that could be addressed by future research projects.

Algorithms↗
PubMed1997

Reconstitution of human telomerase with the template RNA component hTR and the catalytic protein subunit hTRT.

The maintenance of chromosome termini, or telomeres, requires the action of the enzyme telomerase, as conventional DNA polymerases cannot fully replicate the ends of linear molecules. Telomerase is expressed and telomere length is maintained in human germ cells and the great majority of primary human tumours. However, telomerase is not detectable in most normal somatic cells; this corresponds to the gradual telomere loss observed with each cell division. It has been proposed that telomere erosion eventually signals entry into senescence or cell crisis and that activation of telomerase is usually required for immortal cell proliferation. In addition to the human telomerase RNA component (hTR; ref. 11), TR1/TLP1 (refs 12, 13), a protein that is homologous to the p80 protein associated with the Tetrahymena enzyme, has been identified in humans. More recently, the human telomerase reverse transcriptase (hTRT; refs 15, 16), which is homologous to the reverse transcriptase (RT)-like proteins associated with the Euplotes aediculatus (Ea_p123), Saccharomyces cerevisiae (Est2p) and Schizosaccharomyces pombe (5pTrt1) telomerases, has been reported to be a telomerase protein subunit. A catalytic function has been demonstrated for Est2p in the RT-like class but not for p80 or its homologues. We now report that in vitro transcription and translation of hTRT when co-synthesized or mixed with hTR reconstitutes telomerase activity that exhibits enzymatic properties like those of the native enzyme. Single amino-acid changes in conserved telomerase-specific and RT motifs reduce or abolish activity, providing direct evidence that hTRT is the catalytic protein component of telomerase. Normal human diploid cells transiently expressing hTRT possessed telomerase activity, demonstrating that hTRT is the limiting component necessary for restoration of telomerase activity in these cells. The ability to reconstitute telomerase permits further analysis of its biochemical and biological roles in cell aging and carcinogenesis.

Amino Acid Sequence↗
PubMed1997

The effect of educational gifts from pharmaceutical firms on medical students' recall of company names or products.

PURPOSE: To assess the influence of pharmaceutical advertising (in the form of books) directed at medical students and also to examine students' attitudes toward pharmaceutical representatives after interacting with them. METHOD: Two groups of fourth-year medical students were surveyed: 166 residency applicants to the Department of Anesthesia and Critical Care between 1991 and 1993, who were questioned during their personal interviews with the department chair, and 39 fourth-year students from the University of Chicago Pritzker School of Medicine in 1994-95, who were surveyed by telephone. The students were asked if they had ever received a book from a pharmaceutical representative and, if so, to name the book. Then they were asked to name the book-giving company or a product associated with the company. Responses were compared using chi-square analysis. RESULTS: In all, 90% of the students had received one or more books and accurately recalled titles for 89% of them. However, only 25% of the named books were accurately associated with a pharmaceutical company or product. The Pritzker students, asked to recall interactions with pharmaceutical representatives, reported being skeptical of representatives who ignored them because they were students, but they rated as helpful and informative those who conversed with them or gave them gifts. CONCLUSION: Although gifts to medical students do not necessarily engender company or product recall, attention paid to medical students by pharmaceutical representatives engenders goodwill toward the representatives and their messages.

Adult↗
PubMed1996

Respiratory scleroma: a clinicopathologic and ultrastructural study.

Respiratory scleroma (rhinoscleroma) is a chronic granulomatous infection produced by Klebsiella rhinoscleromatis, a gram-negative aerobic coccobacillus. This disease is endemic to Africa, Central and South America, South Central and Eastern Europe, the Middle East, and China. Sporadic cases have been reported in the United States, especially in persons who migrated from the aforementioned areas. The majority of cases affect the nose, but extension to the soft and hard palate, upper lip, and maxillary sinuses also is frequent. This study comprises 11 patients (6 females and 5 males) with respiratory scleroma identified over a 6-year period in Guatemala. Their ages ranged from 16 to 60 years. Light microscopy showed a dense plasmacytic infiltrate, Mikulicz histiocytes, and Russell bodies within the plasma cells. Ultrastructural study revealed Mikulicz histiocytes, cytoplasmic vacuoles containing bacilli, and so-called A and B granules. We favor the term respiratory scleroma for this lesion because it affects not only the nose but also the upper and lower respiratory tracts as well as the mouth.

Adolescent↗
PubMed1996

Serum protein binding of propofol in patients with renal failure or hepatic cirrhosis.

BACKGROUND: Serum protein binding is a limiting factor in the access of drugs to the central nervous system. Disease-induced modifications of the degree of binding may influence the effect of anesthetic drugs. METHODS: The protein binding of propofol, an intravenous anaesthetic agent which is highly bound to serum albumin, has been investigated in serum samples from healthy volunteers, from patients with chronic renal failure not undergoing hemodialysis, from patients with chronic renal failure included in a regular hemodialysis program, and from patients with hepatic cirrhosis. Protein binding was determined by the ultrafiltration technique using an Amicon Micropartition System, MPS-1. RESULTS: The percentage of unbound propofol (mean(SD)) in healthy volunteers (n = 16) was 0.98 (0.48) % showing a high interindividual variability. Chronic renal failure did not significantly modify serum protein binding of propofol. In the chronic renal failure group not undergoing regular hemodialysis (n = 9), unbound propofol was 0.92 (0.34) %. In addition, patients in periodic dialysis did not show changes in propofol binding either compared before (1.11 (0.33) %; n = 13) or after hemodialysis (0.87 (0.38) %; n = 12). A slight decrease in albumin concentration was found in all renal patients (P < 0.05) in comparison to healthy volunteers. Creatinine and urea concentrations were higher in these patients (P < 0.01) but in the postdialysis group, the differences in urea levels were not significant when compared with those of volunteers. No changes in the degree of propofol binding were observed in patients with hepatic cirrhosis (0.97 (0.30) %; n = 14) when compared with the group of healthy volunteers. Significant differences were observed in albumin (P < 0.01) and bilirubin (P < 0.05) concentrations. Considering all subjects, the degree of binding did not correlate with biomedical data. CONCLUSION: Due to the absence of significant changes in the protein binding it is unlikely that there will be an exaggerated pharmacological response in patients with renal and hepatic disease following the administration of a standard propofol dose, although due to interpatient variability careful titration can be recommended.

Adult↗
PubMed1996

Interaction between propofol and sulfisoxazole in mice an in vivo and in vitro study.

The effect of sulfisoxazole on the propofol response has been investigated in an animal model. Doses of propofol (0, 50, 75 and 100 mg/Kg intraperitoneal route) were administered to control (n = 36) and sulfisoxazole pretreated mice (n = 36). The impairment of righting reflex and struggle response were evaluated before and 5, 10, 15, 20, 30, 40, 50 and 60 minutes after propofol administration. Ten minutes after administration of the different doses of propofol, total plasma concentration was measured in both groups by high performance liquid chromatography Protein binding displacement was evaluated in vitro by the ultrafiltration technique. Pretreatment with sulfisoxazole produced an important enhancement in the effect of propofol in both tests. This change was reflected in a significant increase in the area under the time-effect curve (p < 0.001) and in a shift of the log dose-effect relationship to the left. Sulfisoxazole itself did not produce any effect on either test. ED50 for the righting reflex was significantly reduced from 114 mg/kg to 64 mg/kg in sulfisoxazole pretreated groups and it fell from 87 mg/kg to 43 mg/kg for the struggle response test. No changes in the total plasma concentration and protein binding were observed. On the basis of these results, it was concluded that a clinical interaction could be expected but this cannot be explained by an alteration in the protein binding.

Animals↗
PubMed1995

[Postoperative infection and anesthesia: analysis of various risk factors].

OBJECTIVES: To study the possible relation between anesthetic techniques and other perioperative circumstances and factors and the presentation of infections after surgery. PATIENTS AND METHODS: We studied 22 patients who suffered infections after surgery and 54 who did not, analyzing the anesthetic technique used as well as other data on age, sex, concomitant disease, toxic habits, practice of invasive procedures, duration and nature of the surgical procedure and the use of antibiotic prophylaxis. Multivariate analysis (logistical regression) was performed in order to identify independent risk factors. RESULTS: None of the anesthetic techniques studied was associated with greater frequency of postoperative infection. Infected patients were significantly older than uninfected patients (75 +/- 9 years versus 61 +/- 18 years). Likewise the number of infections was higher among ASA III and IV (n = 20) patients than among ASA I and II (n = 2). The duration of surgery for infected patients was 4.15 +/- 2.12 hours whereas it was 2.87 +/- 1.86 hours (p < 0.001) for uninfected patients. Placement of a urinary catheter, repeated surgery, diabetes and blood transfusion all signified greater risk of infection, as did prophylaxis with second and third generation cephalosporins (OR = 12.5; 95% CI = 1.8-85.6) or tobramycin (OR = 66.4; 95% CI = 3.5-1,270). CONCLUSION: The risk of postoperative infection increases with age and poor physical status of patients (ASA III and IV), with diabetes, repeated surgery, transfusion of blood products and prophylaxis with third generation cephalosporins and tobramycin.

Aged↗
PubMed1994

Distinct pattern of embryonic expression of the sea urchin CyI actin gene in Tripneustes gratilla.

Cloning and sequencing of Tripneustes gratilla genomic DNA and cDNA encoding a developmentally regulated, embryonic messenger RNA, referred to as Tg616, revealed an actin-encoding gene orthologous to the CyI actin gene described from Strongylocentrotus purpuratus. Tg616 and SpCyI share: (1) 150 nucleotides of highly conserved sequence 5' of the transcription start site, (2) 95% nucleotide sequence identity in the protein encoding regions, which specify identical amino acid residues in 375 of 377 positions, and (3) extensive nucleotide sequence identity in the 3' untranslated region of their messenger RNAs. Tg616 was therefore designated TgCyI. In situ hybridization shows sequential activation of TgCyI in various cells of the embryo. TgCyI mRNA becomes abundant in primary and secondary mesenchyme cells as they prepare to enter the blastocoel, in prospective aboral ectoderm cells at blastula stage, in gut cells during gut differentiation, and in oral ectoderm at pluteus stage. This pattern of embryonic gene expression is more complex than any of the major patterns of developmentally upregulated genes observed in S. purpuratus embryos and is distinct from SpCyI expression which is progressively restricted to the gut and oral ectoderm.

Actins↗
PubMed1994

Multifocal papilloma virus epithelial hyperplasia.

Multifocal papilloma virus epithelial hyperplasia is an infection of the oral mucosa produced by human papilloma virus types 13 and 32, which primarily bilaterally affects lips, lateral borders of tongue, and buccal mucosa. The attached oral mucosa, floor of mouth, soft palate, and oropharynx are sites that appear not to be affected. This study comprises 110 patients with multifocal papilloma virus epithelial hyperplasia identified over a period of 3 years in Guatemala City and neighboring rural areas. All but four patients were younger than 18 years of age. More than one affected patient was observed in several families. All but three cases occurred in patients living in extreme poverty (annual family income less than $1,200 in U.S. dollars). Biopsies of 60 lesions demonstrated acanthosis and nuclear degeneration within the epithelium. We suggest that the eponym Heck's disease be abandoned because this disease was described in the Latin-American literature before the initial description in the American literature. We propose the term multifocal papilloma virus epithelial hyperplasia, which best describes the nature and multifocality of this disease.

Adolescent↗
PubMed1992

Differential potentiation by calcium antagonists of neuromuscular blockade induced by pancuronium and succinylcholine in cats in vivo.

The effects of several calcium antagonists (verapamil, nicardipine and two diltiazem isomers, d-cis and l-cis diltiazem) alone and associated to non-depolarizing (pancuronium) and depolarizing (succinylcholine) neuromuscular blockers, were evaluated on sciatic nerve-tibialis anterior muscle preparations from cats in vivo. The calcium antagonists used (at 0.1 and 0.5 mg/kg iv) did not modify the height of muscular twitches elicited indirectly. However, these agents potentiated in a dose-dependent way the neuromuscular blockade induced by iv pancuronium (2-40 micrograms/kg) and succinylcholine (6-200 micrograms/kg). The order of potency in increasing the effects of pancuronium was nicardipine much greater than d-cis diltiazem greater than or equal to verapamil, whereas the order of potency in enhancing succinylcholine effects was d-cis diltiazem greater than or equal to verapamil much greater than nicardipine. The effects of diltiazem were stereoselective, thus the potentiation induced by d-cis diltiazem was significantly greater in all cases than that induced by l-cis diltiazem, which suggests that calcium channel blockade plays a role in these interactions. However, other mechanisms such as calcium antagonists-induced nicotinic receptor desensitization may also be involved.

Animals↗
PubMed1990

Characterization and expression of two sea urchin homeobox gene sequences.

We describe two homeobox sequences, TgHbox5 and TgHbox6, isolated from the Hawaiian sea urchin Tripneustes gratilla using a Drosophila Sex combs reduced probe. Sequence analysis shows that the encoded TgHbox5 homeodomain shares only 30-52% amino acid identity with homeodomains encoded by previously characterized genes, establishing that it is a divergent homeobox that is not in any known class of homeoboxes. TgHbox5 is expressed in the embryo as two major developmentally regulated transcripts. one at 5.0 kilobase (kb) appearing by blastula stage and the other at 2.7 kb appearing at pluteus stage. Multiple transcripts from TgHbox5 are present at a much lower level in adult tissues and are predominantly expressed in small and large intestines. The TgHbox6 homeobox is an Antenna-pedia-class homeobox, which appears not to be expressed during embryogenesis but produces abundant 3.6 and 3.2 kb transcripts in the six adult tissues examined.

Amino Acid Sequence↗
PubMed1988

Differential effects of calcium channel blocking agents on pancuronium- and suxamethonium-induced neuromuscular blockade.

The effects were studied of several calcium channel blocking agents on muscle twitch, and possible interactions between these drugs and pancuronium and suxamethonium, using a rat phrenic-hemidiaphragm preparation. Nicardipine, verapamil and diltiazem each caused a concentration-related depression of muscle response. Nicardipine had the most, and diltiazem the least, potent effect. Verapamil and diltiazem 5 and 10 mumol litre-1 caused a concentration-dependent enhancement of suxamethonium-induced neuromuscular blockade, but increased the effect of pancuronium only at 10 mumol litre-1. Nicardipine 10 mumol litre-1 significantly enhanced pancuronium-induced neuromuscular blockade, but not that produced by suxamethonium.

Animals↗
PubMed1986

Stage-specific expression of a homeo box-containing gene in the non-segmented sea urchin embryo.

Hybridization of Drosophila homeo box DNA probes to Southern transfers of genomic DNA from the Hawaiian sea urchin Tripneustes gratilla has revealed that the sea urchin genome contains at least five homeo boxes. Examination of the DNA from several individuals shows that the sequences flanking these homeo boxes exhibit little restriction fragment length polymorphism, indicating they are more highly conserved than the majority of sea urchin DNA. Several clones in a T. gratilla genomic DNA library which hybridized with Drosophila homeo box probes were identified, and one found to be transcribed during embryogenesis was selected for further study. Southern transfer hybridizations showed the cloned gene to be single-copy. DNA sequencing of the sea urchin gene defined a homeo box 70-73% homologous to the Drosophila homeo box probes and an encoded homeo domain 78-88% homologous to those encoded by the probes. Hybridization of DNA probes from the sea urchin homeo box-containing gene to Northern transfers of embryonic RNA demonstrated that the gene produces two transcripts of 6.9 kb and 7.7 kb. Transcripts first accumulate at blastula stage and increase to a maximum level at gastrula stage before decreasing considerably in abundance by pluteus stage.

Amino Acid Sequence↗
PubMed1986

Radiological analysis of hemifacial spasm with special reference to angiographic manifestations.

Fifty-one patients with hemifacial spasm secondary to facial nerve compression by normal appearing, elongated, tortuous and/or dilated arteries, were treated by microsurgical neurovascular decompression. Post-operatively, 91% of 44 of these patients with one to six year postoperative follow-ups were satisfactory. The angiographic findings showed significant increase in the number of common trunk anomalies. Variations of the anterior and posterior inferior cerebellar and vertebral arteries are discussed in relation to nerve compression.

Adult↗