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Biomedical subjects

E Silva

Publications and source records attributed to E Silva.

At least 19 recordsLinked to original sources
PubMed1995

Concurrence of Clostridium difficile toxin A enzyme-linked immunosorbent assay, fecal lactoferrin assay, and clinical criteria with C. difficile cytotoxin titer in two patient cohorts.

The accurate and sensitive diagnosis of Clostridium difficile-related diarrhea, normally treated with vancomycin, has become increasingly important in light of the emergence of dangerous new strains of vancomycin-resistant enterococci. In order to improve the threshold for C. difficile diagnosis and treatment, a number of commonly used assays for the diagnosis of C. difficile diarrhea were examined. These included an enzyme-linked immunosorbent assay for C. difficile toxin A (ToxA), a CHO cell culture assay for fecal C. difficile (cyto)toxin B, and a lactoferrin latex agglutination assay for fecal lactoferrin (LFLA). We studied 722 fecal specimens submitted by physicians for C. difficile toxin testing at the Salem, Va., Veterans' Affairs Hospital and at the University of Virginia Medical Center in Charlottesville. Charts were reviewed from 123 Veterans' Hospital patients and 114 University of Virginia patients for clinical criteria indicative of C. difficile diarrhea. An increasing titer of CHO cell cytotoxicity was correlated with an increasing likelihood of ToxA positivity (5 to 90%), LFLA positivity (39 to 77%), and clinical agreement (28 to 85%). However, some data indicate that the CHO cell cytotoxicity assay may be nonspecific when positive only at low titers. When the CHO assay result is positive at high titers, it remains the best diagnostic tool. Yet, when it is positive at a low titer, careful interpretation of the results in conjunction with other assays and the clinical setting is warranted, especially in light of new drug-resistant strains of microorganisms.

Animals↗
PubMed1995

Peritoneal papillary serous carcinoma: response to Taxol in platinum resistant disease.

A case of peritoneal papillary serous carcinoma which developed after total abdominal hysterectomy and bilateral salpingo-oophorectomy for a benign condition is presented. The patient was treated with platinum-based chemotherapy to which she initially responded, but then the tumor progressed. High dose paclitaxel (250 mg/m2) was given. The patient tolerated this treatment well, achieving a rapid partial response with good palliation of symptoms. Paclitaxel should be considered for patients with a platinum resistant peritoneal papillary serous carcinoma.

Carboplatin↗
PubMed1994

In vivo diagnosis of cervical intraepithelial neoplasia using 337-nm-excited laser-induced fluorescence.

Laser-induced fluorescence at 337-nm excitation was used in vivo to differentiate neoplastic [cervical intraepithelial neoplasia (CIN)], nonneoplastic abnormal (inflammation and human papilloma viral infection), and normal cervical tissues. A colposcope (low-magnification microscope used to view the cervix with reflected light) was used to identify 66 normal and 49 abnormal (5 inflammation, 21 human papilloma virus infection, and 23 CIN) sites on the cervix in 28 patients. These sites were then interrogated spectroscopically. A two-stage algorithm was developed to diagnose CIN. The first stage differentiated histologically abnormal tissues from colposcopically normal tissues with a sensitivity, specificity, and positive predictive value of 92%, 90%, and 88%, respectively. The second stage differentiated preneoplastic and neoplastic tissues from nonneoplastic abnormal tissues with a sensitivity, specificity, and positive predictive value of 87%, 73%, and 74%, respectively. Spectroscopic differences were consistent with a decrease in the absolute contribution of collagen fluorescence, an increase in the absolute contribution of oxyhemoglobin attenuation, and an increase in the relative contribution of reduced nicotinamide dinucleotide phosphate [NAD(P)H] fluorescence as tissue progresses from normal to abnormal in the same patient. These results suggest that in vivo fluorescence spectroscopy of the cervix can be used to diagnose CIN at colposcopy.

Cervix Uteri↗
PubMed1994

Community prevalence of hepatitis C viraemia: a polymerase chain reaction study.

In order to estimate the prevalence of HCV carriage in an inner city health district, we undertook a polymerase chain reaction (PCR) based survey of sera collected from 1,0002 patients attending general practitioners for reasons unrelated to liver disease. The series comprised 305 sample selected sera patients sample from sera 995 patients previously screened by C100 antigen-based anti-HCV tests. Overall, 7 patients were positive for HCV RNA. Four cases had anti-C100 antibodies to HCV, 2 were strictly negative but had high-normal/borderline optical densities by ELISA assay, while one was completely anti-HCV negative. All but one had normal liver function tests. Only 3/7 PCR positive cases had any serum marker for hepatitis B (HBV) exposure (2 HBsAg positive, 1 IgM anti-HBc positive). The minimum point prevalence of HCV carriage in this community is 0.7%, approximating the HBsAg carriage in the same population (1%). HCV carriage in this inner city population is considerably higher than would be predicted by blood donor surveys. A positive anti-HCV anti-body (anti-C100) test is poorly predictive (approximately 10%) of HCV RNA carriage in a general practice based population in which measurement of "surrogate" (HBV related) HCV markers would have detected only 3/7 cases of presumed chronic HCV carriage.

Adult↗
PubMed1994

Nucleolar organizer regions: a potential prognostic factor in adenocarcinoma of the endometrium.

Nucleolar organizer regions, which are evaluated using a silver stain for paraffin-embedded sections (AgNOR), can be used as a measurement of cellular proliferative activity. In the endometrium significant differences have been seen between benign and malignant lesions. To determine if AgNOR counts are of prognostic value in endometrial cancer, we examined 28 patients who developed recurrent disease after surgical stage Ib and Ic endometrial cancer and compared this group with a matched control group of patients who did not develop recurrence. The mean AgNOR number per cell was significantly higher in patients with recurrent disease (P = 0.001). Only five of these patients had values less than 4, whereas only three of the control group had values higher than 4. There was also a significant difference in the percentage of cells with more than 5 and more than 8 AgNORs (P = 0.001). After radiation therapy, the number of AgNORs per cell decreased. Recurrent tumors had higher AgNOR counts than the respective primary tumors. In conclusion, patients at increased risk for recurrent endometrial cancer can be identified by high AgNOR counts. Further evaluation of this parameter and comparison to other prognostic factors seems warranted.

Adenocarcinoma↗
PubMed1994

Riboflavin-sensitized photoprocesses of tryptophan.

The photodegradation of tryptophan in oxygen saturated aqueous solution sensitized by riboflavin is accompanied by the generation of the following reactive oxygen species: 1O2, OH., H2O2 and O2.-. When parallel photodegradation experiments are run with 14C-riboflavin in one case and 14C-tryptophan in the other and the irradiation products are separated by Sephadex G-15 and C18-HPLC, the generation of the following species is detected: aggregate forms of riboflavin, indolic products associated to flavins, indolic products of molecular weight higher than tryptophan, formylkynurenine, and other tryptophan photodecomposition products. The significance of the riboflavin anion radical and tryptophan cation radical as intermediates in the photoproduct formation is discussed.

Catalase↗
PubMed1994

Visible light effects on tumoral cells in a culture medium enriched with tryptophan and riboflavin.

When NSO/2 myeloid cell line and teratocarcinoma F9 cells were irradiated in Dulbecco's modified Eagle medium enriched with tryptophan and riboflavin, toxic photoproducts for these tumoral cells were generated. The active participation of 1O2 and .OH was established using specific scavengers and quenchers. A cytotoxic effect was also observed when unirradiated tumoral cells were incubated in a previously irradiated culture medium enriched with tryptophan and riboflavin. When irradiated medium was used alone, enriched only with tryptophan or only with riboflavin, no toxic effect was observed. The relevance of charge transfer processes between triplet riboflavin and tryptophan in the generation of cytotoxic photoproducts is discussed.

Animals↗
PubMed1994

Pertussis in Massachusetts, 1981-1991: incidence, serologic diagnosis, and vaccine effectiveness.

Massachusetts provides diphtheria-tetanus toxoid-pertussis (DTP) vaccine, and since 1980 has monitored pertussis with a statewide diagnostic service. The incidence of bacteriologically confirmed pertussis was 104.5 per 100,000 person-years in 1-month-old infants and declined progressively thereafter. Infants < 6 months old experienced disproportionate morbidity: 44% of bacteriologically confirmed pertussis, 64% of hospitalizations, and 71% of hospital days. Most children with pertussis had received < 3 DTP doses during childhood, whereas 87% of adolescents with pertussis had received > or = 4 doses. Serodiagnosis by single serum anti-pertussis toxin antibody ELISA increased the incidence of confirmed pertussis in persons 11-19 years old from 3.0 to 12.9 per 100,000 and in persons > or = 20 years old from 0.16 to 0.56 per 100,000. Bacteriologic methods underestimate pertussis incidence, but a single serum anti-pertussis toxin antibody ELISA is a practical method for population-based diagnosis in adolescents and adults.

Adult↗
PubMed1994

[Ebstein's anomaly of the tricuspid valve. Clinical tolerance up to 38 years of age and pregnancy].

Ebstein's Anomaly of the tricuspid valve has a variable degree of abnormality with a continuous change between mild and severe forms and, consequently, a variable clinical course. Pregnancy can also be well tolerated with a good fetal outcome. The authors present a case of a 44 year old woman with Ebstein's Anomaly of the tricuspid valve. Clinical evolution to the age of 38 and two term pregnancies in the third decade of life were well tolerated. The infants were normal and had an adequate development.

Adult↗
PubMed1994

Riboflavin sensitized photooxidation of tyrosine.

The oxygen reactive species generated during the photooxidation of tyrosine sensitized by riboflavin were studied and the products formed were isolated. It was found that this process occurs preferently through a type I mechanism, which involves the direct interaction between the excited state of the sensitizer and tyrosine. The formation of O2.-, H2O2 and .OH was detected along the photooxidative process. By changing H2O by D2O it could be established that 1O2 has no significant role in the photooxidation of tyrosine sensitized by riboflavin. When a previously irradiated solution of tyrosine was applied to a Sephadex G-15 column, four fractions could be separated corresponding to products having hydrodynamic volumes larger than those of the reactants. By the use of 14C-tyrosine the aminoacidic origin of the products could be determined; one of them was identified as bityrosine, according to its fluorescence properties and 1H-NMR spectrum.

Azides↗
PubMed1994

Hyponatremia and neuroleptic-induced obesity in rats.

The weight gain and hyperphagia induced by chronic administration of sulpiride in female rats were not prevented by the concomitant administration of an extra source of sodium. In addition, serum sodium levels were not affected, but potassium levels were significantly reduced by sulpiride administered for 1 week. These results suggest that sulpiride-induced obesity in rats is not related to sodium imbalance. The mechanism for the decrease in serum potassium levels and its relation with sulpiride-induced weight gain warrant further investigation.

Animals↗
PubMed1994

Compartment syndrome associated with infection of the upper extremity.

Compartment syndrome is a potentially devastating entity associated with a great variety of injuries, but to the authors' knowledge there are no known reports of infection documented as a cause. A retrospective review of 263 patients with upper extremity infections admitted to the orthopaedic infection ward during 1992 was conducted to identify patients with compartment syndrome directly associated with infection. Four patients' clinical presentations fulfilled the criteria: two presented with infection and compartment syndrome, and two developed compartment syndrome 2-12 hours after admission. All four had beta-hemolytic streptococci on initial culture; three of four grew Group A streptococcus. Fasciotomies and serial debridements were necessary. One patient ultimately underwent amputation through the elbow.

Adult↗
PubMed1993

Traumatic rupture of the stomach secondary to Heimlich maneuver.

The case of a 93-year-old man who received a Heimlich maneuver while choking is reported. After the procedure, the patient presented with abdominal pain and ultimately was found to have developed a gastric rupture. He was hospitalized for 66 days. Review of the literature showed that only four gastric perforations related to the Heimlich maneuver have been documented. Other complications have occurred. It is reasonable to perform the procedure as an alternative to asphyxiation, but emergency physicians must be aware of the fact that life-threatening complications may ensue.

Aged↗
PubMed1992

Riboflavin-photosensitized anaerobic modification of rat lens proteins. A correlation with age-related changes.

When rat lens homogenate or its soluble protein fractions are irradiated in the presence of riboflavin, a photo-adduct is obtained between this vitamin and the lens proteins. Irradiation of these proteins in the presence of riboflavin also leads to a modification in the chromatographic elution pattern with an increase in the high-molecular-weight fraction. In an aging study with rats, it was shown that the proportion of the high-molecular-weight protein fraction significantly increased with age, whereas the proportion of the low-molecular-weight protein fraction concomitantly decreased. It is postulated that aging produces an increase in the accessibility of the tryptophan residues of the lens proteins, as established by iodide fluorescence quenching experiments.

Aging↗
PubMed1992

Pertussis outbreaks in groups claiming religious exemptions to vaccinations.

Four recent outbreaks of pertussis in Massachusetts illustrate some features that contribute to the increased incidence of the disease. The outbreaks involved unimmunized groups of children with philosophical or religious exemptions from school or day-care immunization requirements and children and adults who were reluctant to undergo antibiotic prophylaxis or therapy. Parents and physicians should be aware that failure to immunize and to cooperate in follow-up preventive measures can have public health and potential medicolegal repercussions.

Adolescent↗
PubMed1992

Uterine papillary serous carcinoma (UPSC) treated with cisplatin, doxorubicin, and cyclophosphamide (PAC).

Uterine papillary serous carcinoma (UPSC) is an aggressive malignancy that accounts for a disproportionate number of intraabdominal failures among endometrial carcinoma patients. The histologic appearance and tendency toward intraabdominal spread resemble those of papillary serous adenocarcinoma of the ovary. Because approximately 70% of untreated ovarian carcinoma patients respond to platinum-based chemotherapy, it has been suggested that UPSC patients might respond to similar treatment regimens. Twenty patients with UPSC were treated with cisplatin, doxorubicin (Adriamycin), cyclophosphamide (PAC) chemotherapy between January 1982 and December 1989. They included 9 patients with advanced primary disease, 5 with recurrence, and 6 who received PAC as adjuvant therapy. Patients received a mean of five cycles of PAC. Only 2 of 11 patients with measurable disease greater than 2 cm achieved complete clinical responses of 12 and 31 months duration; there were no partial responses. Actuarial 5-year survival for all patients was 23%. The mean progression-free interval was 9 months. Patients with clinical stages I or II disease had a higher survival rate than those with stage III or IV disease (P = 0.003). Survival did not correlate with depth of myometrial invasion (P = 0.81) or size of residual tumor following initial surgery (P = 0.16). Estrogen or progesterone receptors were detected in 10 of 11 tumors tested. Seven of 9 patients tested had elevated serum levels of CA-125 (greater than 35 U/ml). Correlation between CA-125 value and clinical course was demonstrated in 3 of 5 patients who had serial measurements. Of all patients, 3 are currently alive; 1 has documented disease. Moderate to severe toxicity was seen in 14 patients (70%). There was one possible treatment-related death from cardiomyopathy. UPSC, despite its histologic and clinical similarities to ovarian carcinoma, was relatively resistant to PAC chemotherapy in this mixed group of patients.

Adult↗