Biomedical subjects

L Cosentino

Publications and source records attributed to L Cosentino.

At least 19 recordsLinked to original sources

PubMed2002

Anti-ENA antibodies in patients with chronic hepatitis C virus infection.

The aim of the study was to assess the prevalence of anti-extractable nuclear antigen (ENA) antibodies in patients with chronic HCV infection. We studied 69 consecutive patients with chronic hepatitis C, 59 control subjects with non-HCV liver diseases, and 22 control subjects with extrahepatic, non-immune-mediated, chronic diseases. Thirty-two (46.3%) of 69 patients with HCV infection had anti-ENA antibodies: 16 (23.1%) showed anti-SSA antibodies and 14 (20.2%) had anti-SSB antibodies. Four of the patients with HCV infection suffered from sicca syndrome and three of them had also anti ENA antibodies. The prevalence of anti-ENA antibodies was significantly higher in the anti-HCV subjects compared with both control groups. Twenty-six of 44 HCV-antibodies-positive females had anti-ENA antibodies, compared with 6 of 25 males, showing a sex related difference. In conclusion, our results outline a specific role of HCV infection in the induction of anti-ENA antibodies. Female sex seems a predisposing condition.

Antibodies↗

PubMed2001

Further characterization and validation of gpt delta transgenic mice for quantifying somatic mutations in vivo.

The utility of any mutation assay depends on its characteristics, which are best discovered using model mutagens. To this end, we report further on the characteristics of the lambda-based gpt delta transgenic assay first described by Nohmi et al. ([1996]: Environ Mol Mutagen 28:465-470). Our studies show that the gpt transgene responds similarly to other transgenic loci, specifically lacZ and cII, after treatment with acute doses of N-ethyl-N-nitrosourea (ENU). Because genetic neutrality is an important factor in the design of treatment protocols for mutagenicity testing, as well as for valid comparisons between different tissues and treatments, a time-course study was conducted. The results indicate that the gpt transgene, like cII and lacZ, is genetically neutral in vivo. The sensitivities of the loci are also equivalent, as evidenced by spontaneous mutant frequency data and dose- response curves after acute treatment with 50, 150, or 250 mg/kg ENU. The results are interesting in light of transgenic target size and location and of host genetic background differences. Based on these studies, protocols developed for other transgenic assays should be suitable for the gpt delta. Additionally, a comparison of the gpt and an endogenous locus, Dlb-1, within the small intestine of chronically treated animals (94 microg/mL ENU in drinking water daily) shows differential accumulation of mutations at the loci during chronic exposure. The results further support the existence of preferential repair at endogenous, expressed genes relative to transgenes.

Animals↗

PubMed2001

Selective use of endoscopic retrograde cholangiopancreatography to facilitate laparoscopic cholecystectomy without cholangiography. A review of 1139 consecutive cases.

BACKGROUND: The aim of this study was to show that laparoscopic cholecystectomy can be performed safely without routine intraoperative cholangiography. METHODS: We performed a retrospective analysis of 1139 consecutive patients (376 men and 763 women with an average age of 51.4 years) who underwent laparoscopic cholecystectomy between 1991 and 1999. In all, 227 patients (20%) were selected to undergo preoperative endoscopic retrograde cholangiopancreatography (ERCP) on the basis of four criteria for risk of stones. RESULTS: ERCP allowed us to make a diagnosis of biliary stones in 53.3% of the selected patients. Extraction of the stones was successful in 97% of the cases. In 14% of cases, ERCP was normal; in 32.7%, some useful diagnostic information was obtained. There were three complications (pancreatitis) following endoscopy (complication rate, 1.3%). Laparoscopic cholecystectomy was successful in 92% of patients. The postoperative morbidity rate was 3.2% (major complications, 0.5%). There were no deaths. During a follow-up period ranging from 3 to 97 months, six patients (0.6%) were found to have residual biliary stones. CONCLUSION: This study confirms the hypothesis that laparoscopic cholecystectomy can be performed safely without routine intraoperative cholangiography.

Cholangiopancreatography, Endoscopic Retrograde↗

PubMed2001

Periampullary tumors. Analysis of 319 consecutive cases submitted to preoperative endoscopic biliary drainage.

BACKGROUND: During the last 2 decades, endoscopic retrograde cholangiopancreatography (ERCP) has been widely used for the diagnosis of periampullary tumors and the preoperative or definitive treatment of jaundice. METHODS: We performed a retrospective analysis of 319 consecutive patients (184 men and 135 women with an average age of 66.5 years) who underwent ERCP for periampullary tumors between 1987 and 1999. RESULTS: Endoscopic internal biliary drainage was successful in 293 patients (92%), with some differences due to the origin of the tumor. There were five complications (1.5%), including four bleeds and one retroduodenal perforation. There were no deaths related to the endoscopic drainage. Eighty-four patients underwent pancreaticoduodenectomy. The postoperative morbidity rate was 23%, and the overall mortality rate was 4.8%. CONCLUSION: ERCP is a valid technique for the detailed preoperative assessment of periampullary tumors. It is also a safe method for internal biliary drainage.

Adult↗

PubMed2000

Differential mutation of transgenic and endogenous loci in vivo.

Although chemicals usually induce very similar frequencies of mutations in transgenes and endogenous genes in vivo when given acutely, chronic exposure to N-ethyl-N-nitrosourea (ENU) produced a more complex pattern in which the endogenous locus was spared many mutations. Here, we demonstrate that the effect is neither ENU-specific nor locus-specific, and thus, may be important in the extrapolations of risk assessment and in understanding mutational mechanisms. During chronic mutagen exposure, mutations at the transgene accumulate linearly with time, i.e. in direct proportion to the dose received. In contrast, mutations at the endogenous gene are much less frequent than those of the transgene early in the exposure period and the accumulation is not linear with time, but rather accelerates as the exposure continues. Previous comparisons involved the endogenous Dlb-1 locus and the lacI transgene from the Big BlueMouse in the small intestine. These experiments involved the Dlb-1 locus and the lacZ transgene from the MutaMouse in the small intestine and the hprt locus and the lacZ transgene in splenocytes. Comparisons were made in both tissues after acute and chronic exposures to ENU, the original mutagen, and in the small intestine after exposures to benzo(a)pyrene. All comparisons showed that during chronic exposures mutations at the transgene accumulate linearly with the increasing duration of exposure, whereas induced mutations of the endogenous gene initially accumulate at a slower rate. Thus, the difference in mutational response observed during low chronic treatment is not unique to a particular transgene, endogenous gene, tissue, or mutagen used, but may be a general phenomenon of such genes.

Animals↗

PubMed2000

ENU induces mutations in the heart of lacZ transgenic mice.

The use of transgenic mouse models as somatic mutation assays allows determination of mutation in all tissues of the mouse, including non-dividing tissues. In this regard, these models can be used to study the possibility that mutations can be induced in mitotically quiescent organs such as the heart. Mutations are generally thought to be associated with mitotic processes of DNA replication. Mutations, however, are also postulated to occur in the absence of mitosis as the result of DNA repair. In order to determine whether or not mutations could be induced in the heart, we analyzed the mutant frequency in the hearts of F(1) (Muta Mouse X SWR) mice that had been treated acutely with 250 mg/kg ENU and sampled at days 10, 35, and 70 post-treatment. A significant increase in mutant frequency at day 70 shows that mutations can be induced in the heart. Since the heart contains small numbers of non-muscle cells, additional mechanisms that could explain these results were also considered. The effect of ENU-induced cell proliferation or a sub-population of rapidly dividing cells is ruled out by C(14)-thymidine uptake studies which showed minimal proliferation. By the same token, the influence of ex vivo mutations (i.e., DNA adducts fixed as mutations during replication in the bacteria) is ruled out by the observed time course of mutations, as well as experimental evidence showing that such mutations are not detected in the lacZ assay.

Animals↗

PubMed2000

Effect of exogenous melatonin on mood and sleep efficiency in emergency medicine residents working night shifts.

OBJECTIVE: To determine whether melatonin taken prior to attempted daytime sleep sessions will improve daytime sleep quality, nighttime sleepiness, and mood state in emergency medicine (EM) residents, changing from daytime to nighttime work schedules. METHODS: A prospective, randomized, double-blind crossover design was used in an urban emergency department. Emergency medicine residents who worked two strings of nights, of at least three nights' duration each, and separated by at least one week of days were eligible. Subjects were randomized to receive either melatonin 1 mg or placebo, 30 to 60 minutes prior to their daytime sleep session, for three consecutive days after each night shift. Crossover to the other agent occurred during their subsequent night shifts. Objective measures of quality of daytime sleep were obtained using the Actigraph 1000. This device measures sleep motion and correlates with sleep efficiency, total sleep time, time in bed, and sleep latency. The Profile of Mood States (POMS) and the Stanford Sleepiness Scale (SSS) were also used to quantify nighttime mood and sleepiness. RESULTS: Among the 19 volunteers studied, there was no difference in sleep efficiency (91.16% vs 90.98%, NS), sleep duration (379.6 min vs 342.7 min, NS), or sleep latency (7.59 min vs 6.80 min, NS), between melatonin and placebo, respectively. In addition, neither the POMS total mood disturbance (5.769 baseline vs 12.212 melatonin vs 5.585 placebo, NS) nor the SSS (1.8846 baseline vs 2.2571 melatonin vs 2.1282 placebo, NS) demonstrated a statistical difference in nighttime mood and sleepiness between melatonin and placebo. CONCLUSIONS: There are no beneficial effects of a 1-mg melatonin dose on sleep quality, alertness, or mood state during night shift work among EM residents.

Adult↗

PubMed2000

Prevention with clodronate of osteoporosis secondary to inhaled corticosteroid treatment in patients with chronic asthmatic bronchitis.

Steroid therapy is the third most common cause of osteoporosis, after loss of gonad function and senescence. The aim of the present study was to evaluate the protective action of clodronate on bone mass loss induced by steroid therapy. Sixty patients with bronchial asthma receiving either fluticasone (250 mg x 4/day) or beclomethasone (250 mg x 4/day) inhaled corticosteroid treatment were enrolled. Half the patients received combination treatment with clodronate (100 mg i.m./14 days), for a total period of 12 months. All patients were evaluated at baseline and at the end of treatment for bone mineral density (BMD) and calcium/phosphor metabolism parameters (kalemia, kaluria, phosphoremia, phosphaturia, alkaline phosphatase and hydroxyprolinuria over a 24-h period). The results of this preliminary study confirm the protective influence of clodronate on bone mass loss, as documented by the increment in mean values in BMD reported at the end of treatment compared with baseline values.

Administration, Inhalation↗

PubMed1999

A comparison of the effects of diverse mutagens at the lacZ transgene and Dlb-1 locus in vivo.

Transgenic assays permit the detection of mutations in any tissue, whereas endogenous mutations can be measured in very few. For this reason comparisons between these loci when both can be measured in the same cells are of considerable interest. Previous comparisons have been inconsistent: usually these loci have responded alike, however, in some cases the endogenous locus has been more sensitive and at other times the transgenic locus has been more sensitive. Here we report a comparison of the lacZ transgene of the MutaMouse and the endogenous Dlb-1 gene in the epithelium of the small intestine after acute exposure to seven mutagens. Benzo[a]pyrene, 5-bromo-2'-deoxyuridine, methyl methane sulphonate, ethyl methane sulphonate, N-ethyl-N-nitrosourea, mitomycin C and N-methyl-N-nitrosourea were all given by gavage to F1 (MutaMouse x SWR) mice. Mutations were quantified 2 weeks after the end of treatment. The data shows that all of the agents induced similar mutant frequencies at the Dlb-1 locus and at the lacZ transgene. The acute treatments generally produced only modest increases in mutant frequency at both loci. The higher background frequency observed at the lacZ transgene reduces the ability of the transgenic assay to detect the same absolute increase in mutant frequency.

Animals↗

PubMed1999

The cII locus in the MutaMouse system.

Here, we report the first application and characterization of the cII locus as a mutational target for use with the Muta(trade mark)Mouse system for quantifying somatic mutations in vivo. This locus can be analyzed for mutations using positive selection and is identical in sequence to the cII in the Big Blue((R)) Mouse. The cII displays similar spontaneous (5.5 x 10(-5)) and induced mutation frequencies when compared to the lacZ gene in the small intestine of MutaMice treated with ENU (N-ethyl-N-nitrosourea). After acute treatment with 250 mg/kg ENU (ip) the mutant frequencies were 127 x 10(-5) at the cII and 147 x 10(-5) at the lacZ loci, reaching a maximal mutant frequency 10 days posttreatment and remaining constant thereafter. These data prove that this transgene is genetically neutral, conferring neither selective advantage nor disadvantage on the host cells. The cII dose response curve was linear (R(2) = 0.93) comparable to the lacZ after treatments with 0, 50, 150, or 250 mg/kg ENU. Use of the cII locus (0.3 kb) addresses the single most significant drawback associated with the MutaMouse system, namely the inability to obtain sequence spectra efficiently, due to the large size of the lacZ gene (3.0 kb). Moreover, a less obvious application, but nevertheless of considerable importance, is the easy identification of jackpot mutations, without sequencing. The cII, identical in both sequence and origin on the transgenic constructs used in producing the Big Blue and MutaMouse systems, provides the first transgenic locus common to the two widely used in vivo mutagenesis assays.

Animals↗

PubMed1999

Effects of extended chronic exposures on endogenous and transgenic loci: implications for low-dose extrapolations.

Although transgenic and endogenous loci generally respond alike to acute mutagenic exposures, those loci that have been tested respond differently to daily or continuous exposures. During chronic exposures, the transgenes accumulate mutations linearly, whereas the endogenous loci are less mutable initially but later accumulate mutations at an accelerating rate. The result is a reverse dose rate effect in which the same total dose is more mutagenic for the endogenous locus when spread over a longer time. This makes extrapolations to still lower chronic exposures uncertain. Here we report extension of a chronic exposure to N-ethyl-N-nitrosourea (ENU) in drinking water to longer times and to lower doses. The F(1) of MutaMouse males x SWR that were used permit detection of mutations at both lacZ and Dlb-1. Both of these mutations were found to be genetically neutral over this period. Extension of the exposure from 30 to 90 days at 94 microg/ml/d showed a continuation of the curves found previously for 10 to 30 days, namely, linear for mutations of the lacZ transgene and concave upward for the Dlb-1 endogenous gene. A simple model for these data is presented. Of the extended exposures, only the highest dose produced a significant increase in Dlb-1 mutant frequency, an increase consistent with the model. The time (at 2.8 microg/ml/d), concentration (after 480 days exposure), and dose (concentration x duration of exposure) response curves were not significantly different from linearity. The data for the transgene are not as convincing, due to the high spontaneous mutant frequency, obscuring the induced response.

Animals↗

PubMed1997

Analysis of complications of endoscopic sphincterotomy for biliary stones in a consecutive series of 546 patients.

BACKGROUND: Endoscopic sphincterotomy (ES) plays an important role in treatment of biliary stones; however, there remain some controversies concerning complications of ES, which in most cases seem not to be predictable. METHODS: The aim of this study was a retrospective analysis of complications in 546 consecutive patients (267 males, 279 females, average age 63.7 years) who underwent endoscopic retrograde cholangiography (ERCP) for biliary stones from 1988 to 1995. RESULTS: ES was performed in 535 patients (98%), and extraction of stones was successful in 493 (92%). In all, 29 complications (5.4%) were observed, including bleeding 13, cholangitis seven, cholecystitis four, pancreatitis three, retroduodenal perforation two; of these, four (14%) required an operation. Overall mortality was 0.3%. CONCLUSION: While a significant decrease of the incidence of complications was observed in the course of the study, due to constantly improving experience, no correlation between risk factors and complications was identified.

Adolescent↗

PubMed1996

The relationships among stem cells, crypts, and villi in the small intestine of mice as determined by mutation tagging.

The number of stem cells that maintain a crypt of the small intestine is uncertain. Although the number of stem cells per crypt had been thought to be 10-20, current estimates indicate a much smaller number, possibly 1 stem cell per crypt. We report here that in SWR and C57BL/6 X SWR F1 mice, the results of mutation tagging are inconsistent with the existence of more than one stem cell per crypt. Mutations at the Dlb-1 locus mark the progeny of a single epithelial stem cell in the small intestine and reveal the size of the mutant clone. The epithelial cells are produced in the crypts and migrate up the villi to be sloughed off at the tip so that a mutant clone takes the form of a ribbon on the villus. Because the size of the mutant clones must be inversely proportional to the number of stem cells contributing to the villus, this provides a means of counting the stem cells (ethylnitrosourea was used to induce mutations in the intestine). In the duodenum the ribbons average 0.099 +/- 0.004 villus circumferences, indicating that there are 1/0.099 = 10.2 stem cells per villus. Because there are 10.5 +/- 0.67 crypts/villus, the estimate gives 10.2/10.5 = 0.97 +/- 0.1 stem cells/crypt. Because each crypt must have at least one stem cell, the vast majority can have only one stem cell and very few may have two or more.

Animals↗

PubMed1996

A test for neutrality of mutations of the lacZ transgene.

Neutral mutations are stable alterations in DNA that are neither beneficial nor damaging to the cell. Once a mutation is fixed in the DNA, the mutant frequency should increase to its maximum and plateau thereafter, provided that enough expression time is given. Evidence has been obtained indicating neutrality for the endogenous Dlb-1 locus and for the lacl in the BigBlue transgenic system, and is reported here for lacZ in the Muta Mouse system. We have found that, after an acute dose of ethylnitrosourea (ENU, 250 mg/kg) the mutant frequency for both lacZ transgene and Dlb-1 remained constant between 10 and 70 days after mutagenesis in the small intestine, where cell turnover is rapid (approximately 7 days). The same concept should apply to other tissues.

Animals↗

PubMed1996

Why do stem cells exist?

Self-renewing tissues have a differentiation hierarchy such that the stem cells are the only permanent residents of the tissue, and it is in these cells that most cancerous mutations arise. The progeny of the stem cells either remain stem cells or enter a transient proliferating cell population that differentiates to produce the functional cells of the tissue. The reason that this differentiation hierarchy exists has not been established. We show here that alternative hierarchies, in which there would be no stem cells, are feasible and biologically plausible. We show that current evidence from somatic mutation frequencies at both transgenic and endogenous loci implicates cell division in the origin of most somatic mutations. We suggest, therefore, that the existence of stem cells is an evolutionary consequence of a selective pressure to avoid cancer by reducing the number of somatic mutations. The stem cell hierarchy reduces the number of cell divisions of those cells that reside permanently in the tissue, which reduces the number of somatic mutations and thus minimizes the cancer rate. In the small intestine, the existence of stem cells reduces the mutant frequency in the stem cells by about one order of magnitude. Since two or more mutations are required to transform a cell, the protective effect may be 100-fold or more. Similar factors may be expected in other tissues.

Age Factors↗

PubMed1996

ERCP in the era of laparoscopic biliary surgery. Experience with 407 patients.

BACKGROUND: The combined endoscopic and laparoscopic treatment of biliary stones is now highly debated, especially as regards possible complications compared to one-step laparoscopic treatment. METHODS: This study analyzes 407 cases (116 males, 291 females, average age 49 years, range 2-87) observed in the period from May 1991 to July 1994. All patients were evaluated preoperatively for the presence of biliary stones. Considering clinical presentation, blood analysis, ultrasonography, and medical history, 99 patients (24%) were selected for preoperative endoscopic retrograde cholangiopancreatography (ERCP). One patient refused preoperative ERCP. RESULTS: Thirty-nine patients (40%) were found to have biliary stones and were submitted to therapeutic endoscopic sphincterotomy (ES). Endoscopic clearance of the bile ducts was achieved in all patients, with one complication (pancreatitis). In performing laparoscopic cholecystectomy, no technical difficulties could be attributed to ERCP, nor were there any conversions in patients who had had preoperative ERCP. Average postoperative hospital stay was 2.5 days. During a follow-up period of from 2 to 39 months, we diagnosed three patients (0.7%) with symptomatic residual stones. They were submitted to successful ERCP and extraction of the stones. CONCLUSIONS: We conclude that ERCP offers an accurate preoperative selection of patients, allows for effective planning of treatment, and simplifies laparoscopic surgery.

Adolescent↗

PubMed1995

The induction of dominant somatic mutations at the Dlb-1 locus.

In the small intestine of heterozygous mice (Dlb-1b/Dlb-1a), the Dlb-1b allele results in a stainable epithelium. The mutation or loss of the dominant Dlb-1b allele in a stem cell results in a non-staining ribbon of cells on a villus of the small intestine. To determine if dominant mutations resulting in the gain of staining--the induction of a Dlb-1b-like allele--could also be detected, we examined Dlb-1a homozygous mice (SWR) 2 weeks after a single treatment with 250 mg/kg ethylnitrosourea. Mutations to the dominant allele should appear as brown ribbons on unstained villi. Such ribbons were observed in the treated group but not in controls. The mutant frequency was low compared to the frequency of Dlb-1a-like mutations reported at the Dlb-1b allele in heterozygous mice.

Animals↗

PubMed1993

HIV-1 isolates from children with or without AIDS have similar in vitro biologic properties.

OBJECTIVE: To compare biologic properties of HIV-1 isolates from children with and without AIDS as a measure of viral cytopathogenicity. PATIENTS AND PARTICIPANTS: Virus isolates from peripheral blood mononuclear cells of 13 perinatally infected children were compared for specific in vitro biologic properties. METHODS: Virus isolates were examined for biologic properties as measured by their ability to infect H9 cells and to induce syncytia in susceptible cells. RESULTS: Most of the pediatric HIV-1 isolates failed to infect CD4+ H9 cells and induce syncytia in susceptible cells, regardless of whether they were from children with or without AIDS. All of the isolates, however, grew well in mitogen-stimulated normal adult lymphocytes. These results are in contrast to those with HIV-1 isolates from adults, whose biologic properties were related to the stages of the disease. CONCLUSIONS: These results indicate that, unlike adult HIV-1 isolates, the biologic properties of pediatric isolates are not related to the stages of the disease. The rapid development of disease in children may therefore be due to factors other than intrinsic properties of HIV-1 strains present in children.

Acquired Immunodeficiency Syndrome↗