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C Wolff

Publications and source records attributed to C Wolff.

At least 37 records · Page 2Linked to original sources
PubMed1996

Mismatch response of the human brain to changes in sound location.

WE investigated whether the enhanced negativity of the human event-related brain potential elicited by changes in auditory lateralization is due to a higher-order change-detection process or whether it can be explained exclusively in terms of selective sensory adaptation. Infrequent changes in lateralization of a repetitive standard tone, generated by changes in interaural time differences, elicited a frontocentrally distributed negative brain wave in the 100-250 ms range relative to stimulus onset. This brain wave was also elicited when possible sensory adaptation was prevented by controlling for the state of refractoriness of location-specific neurones. The results demonstrate that changes in lateralization elicit a genuine mismatch negativity (MMN), indicating the activity of an automatic higher-order change-detection process.

Adult↗
PubMed1996

Significance of human cytomegalovirus DNA detection in immunocompromised heart transplant patients.

Peripheral blood samples (n= 1240), obtained at variable intervals from 483 heart transplantation (HTx patients under immunosuppressive therapy, and blood samples (n=1013) obtained upon blood donation from 1013 healthy anti-human cytomegalovirus (HCMV) positive blood donors, were tested for HCMV DNA by nested polymerase chain reaction (PCR). The detection limit of the nested PCR was determined to be less than 10 copies of the plasmid pRR 47, containing the HCMV immediate early gene. HCMV DNA was detected in 79 of 483 HTx patient (17%). To the contrary' HCMV DNA was only detected in 1 of 1013 anti-HCMV positive, healthy blood donors (0.1%). This PCR positive donor had recently contracted a primary HCMV infection. The rate of HCMV PCR positive immunosuppressed HTx patients in our study was lower than the rate of HCMV PCR positive healthy blood donors in previous reports in the literature. Blood samples (269 from 117 HTx patients) were assayed for HCMV DNA in peripheral blood leukocytes, HCMV DNA in plasma, and HCMV tegument protein 65 kDa (pp 65 antigen). Three laboratory diagnostic patterns were observed and related to clinical findings: (1) HCMV DNA only in leukocytes was observed in 26 patients, 7 of whom had HCMV disease, 5 of whom had graft rejection, and 14 of whom had no specific symptoms; (2) HCMV DNA both in leukocytes and in plasma (viremia) was observed in 3 patients, who were all symptomatic with HCMV disease; (3) HCMV DNA in leukocytes and in plasma (viremia) and pp 65 antigen were observed in 13 patients, all of whom were symptomatic (10 patients had HCMV disease, and 3 patients had graft rejection). A similar sequence of diagnostic patterns was observed in all symptomatic HCMV infections and reactivations in this study: HCMV DNA appeared first in peripheral blood leukocytes, then also in plasma, followed by pp 65 antigen detectable in peripheral blood leukocytes. Upon clinical recovery, these findings disappeared in reverse order. However, HCMV DNA remained detectable in peripheral blood leukocytes for several weeks. The detection of HCMV DNA in the peripheral blood is an exception, not the rule, even in severely immunosuppressed HTx patients. It indicates a pathological condition, albeit without clinical symptoms in some patients, and it is the earliest signal of HCMV replication. Of 42 patients in whom HCMV DNA was initially detected only in peripheral blood leukocytes, 16 patients progressed into viremia. Thus, HCMV-specific PCR performed on nucleic acid extracts from lysed peripheral blood is an appropriate method for the monitoring of HCMV infections in immunosuppressed HTx patients.

Antibodies, Viral↗
PubMed1996

Polymerase chain reaction versus culture for detection of Ureaplasma urealyticum and Mycoplasma hominis in the urogenital tract of adults and the respiratory tract of newborns.

The efficiency of the polymerase chain reaction (PCR) was compared with that of culture for detection of Ureaplasma urealyticum and Mycoplasma hominis in 726 clinical specimens comprising 189 gynecological samples, 362 urological samples, and 175 samples from newborn infants. The sensitivity of PCR versus culture was 95% for both organisms, while the sensitivity of culture versus PCR was 91% for Ureaplasma urealyticum and 84% for Mycoplasma hominis. Furthermore, PCR tests were faster than culture tests, allowing the time to diagnosis to be reduced from two to five days to 24 h.

Adult↗
PubMed1996

One of the lowest validated incidence rates of insulin dependent diabetes mellitus in the Americas: Santiago, Chile.

The goal of this study was to estimate the average annual incidence rate of insulin-dependent diabetes mellitus (IDDM) in Santiago as part of a Multinational Project in Childhood Diabetes (Diabetes Mondiale or DiaMond). Incidence was calculated among subjects under 15 years of age, through a retrospective search and confirmation method from 1 January 1986 to 31 December 1992. Hospitals and private offices of endocrinologists and specialists in diabetes were surveyed. A total of 252 registered cases, 118 boys and 134 girls, for an annual incidences of 2.36/100,000 hab.year. which is one of the lowest validated rates in the Americas.

Adolescent↗
PubMed1996

Longitudinal monitoring of latent and active human cytomegalovirus infections in peripheral blood of heart transplant recipients by single-tube nested RT-PCR.

PCR is a sensitive diagnostic tool for the detection of human cytomegalovirus (HCMV) DNA in the peripheral blood of immunosuppressed transplant recipients. However, its specificity as a prognostic marker for clinical disease is unclassified, because infections considered to be latent may be detected by this method. In order to diagnose active viral infections, we used reverse transcription-PCR (RT-PCR) to identify HCMV mRNA in blood. We developed a single-tube nested RT-PCR with preformed PCR mixtures embedded in a trehalose matrix. Blood samples of 48 heart transplant recipients were investigated for HCMV DNA. 8 patients detected to be HCMV DNA positive after transplantation were investigated in longitudinal monitoring for at least 6 months. HCMV mRNA was found in 5 patients who developed HCMV related symptoms during the period of RNA detection. There was no clear relation between the onset of DNA detection and the first demonstration of mRNA. In 2 patients HCMV DNA could be detected 74 and 81 days before the appearance of mRNA, suggesting long persistence until active infection is started. In 3 patients HCMV mRNA disappeared during or immediately after the end of ganciclovir therapy. In contrast, HCMV DNA was detectable continuously for prolonged periods after therapy, indicating that the persistence of HCMV DNA is not influenced by ganciclovir treatment. In summary, HCMV DNA detection seems to be a reliable early marker for the differentiation of persistent and active HCMV infections in immunosuppressed patients. Our data show that viral mRNA detection is probably a better predictor of the effectiveness of antiviral therapy than viral DNA detection.

Antibodies, Viral↗
PubMed1996

Preattentive periodicity detection in auditory patterns as governed by time and intensity information.

The present study demonstrated that the mismatch negativity (MMN), generated by the brain's preattentive detection of a sound change, is elicited by infrequent reversals of two consecutive tones differing in intensity. When tones were presented in a pairwise manner, the MMN was time-locked to the onset of the intensity reversal. When the tones were continuously presented, the MMN was elicited by an irregular loud tone succeeding a regular loud tone but not by an irregular soft tone following a regular soft tone. Results suggest that the preattentive construction of auditory units is primarily governed by the timing of tone presentation but that it may also utilize intensity information, when no sufficient timing information is available.

Acoustic Stimulation↗
PubMed1996

[Incidence of insulin-dependent diabetes mellitus in Santiago, Chile (1990-1993)].

The aim of this study was to determine IDDM incidence in the Metropolitan Region of Chile, during the period 1990-1993 as part of the Multinational Project for Childhood Diabetes (WHO DIAMOND Project Group). The studied population was 1499.784 inhabitants. All children in whom the diagnosis was made between January 1, 1990 and December 31, 1993 were included. We used a retrospective and prospective search and confirmation method, using as data sources public and private hospitals and medical records of Pediatricians. The Juvenile Diabetes Foundation was used as a secondary data source. All cases had at least two confirmation sources. A total of 176 new cases (90 male) were diagnosed in the study period, with an annual incidence of 2.92/100,000 for females and 2.95 for males. The group of children from 10 to 14 years old had the highest incidence rate (4.9/100,000), specially in women (5.25/100,000). The yearly incidence was 1.31 in 1990, 2.71 in 1991, 2.93 in 1992 and 3.7/1000,000 in 1993. It is concluded that the Metropolitan Region has one of the lowest incidences of IDDM in Latin America, although it increased along the study years.

Adolescent↗
PubMed1996

[Treatment of porphyria cutanea tarda with chloroquine and its effect on associated liver disease: retrospective analysis].

BACKGROUND: Chloroquine may improve cutaneous symptoms and liver disease manifestations in patients with porphyria cutanea tarda. AIM: To retrospectively analyze the effects of choloroquine in patients with porphyria cutanea tarda. PATIENTS AND METHODS: Five patients (one female), aged 45 to 65 years old, were studied. The duration of the disease ranged from 2 to 15 years. One patient was alcoholic and other was a hepatitis C virus carrier. All patients received chloroquine 125 mg twice weekly. Before, during and after treatment, cutaneous signs, serum bilirubin, hepatic enzymes and urine copro and uroporphyrin were assessed. Four patients were subjected to a liver biopsy before starting chloroquine. RESULTS: All patients had increased levels of urine porphyrins, four had abnormal serum liver enzymes. All liver biopsies showed variable hemosiderosis, two patients had a chronic active hepatitis (one with cirrhosis), one a chronic persistent hepatitis and one had mild rague alterations. During chloroquine treatment, cutaneous symptoms improved in all patients, transaminases and gamma glutamyl transferase decreased. In three, urine uroporphyrin increased initially and normalized afterwards. Choloroquine was well tolerated. CONCLUSIONS: Chloroquine improved cutaneous symptoms, urine uroporphyrin and serum liver enzyme levels in treated patients.

Aged↗
PubMed1995

Human cytomegalovirus immediate early and late transcripts in peripheral blood leukocytes: diagnostic value in renal transplant recipients.

Peripheral blood leukocytes of renal transplant recipients were investigated to compare the following markers of human cytomegalovirus (HCMV) infection: pp65 antigen by indirect immunofluorescence, viral DNA by nested polymerase chain reaction (PCR), and immediate early (IE) and late (pp150) mRNA by nested PCR following reverse transcription. Sixty-five patients were monitored weekly for 20 weeks after transplantation. In 76 samples from 20 patients positive for HCMV DNA by PCR, HCMV mRNA was detected. Detectable amounts of IE and pp150 mRNA were positively correlated with high numbers of pp65 antigen-positive cells and confirmed the significance of pp65 antigen as a marker for active viral replication. However, with respect to the early diagnosis of HCMV-related disease and monitoring of antiviral therapy, the test for viral mRNA was not superior to the pp65 antigen test.

Base Sequence↗
PubMed1995

Conserved and divergent expression aspects of the Drosophila segmentation gene hunchback in the short germ band embryo of the flour beetle Tribolium.

The segmentation gene hunchback (hb) plays a central role in determining the anterior-posterior pattern in the Drosophila embryo. We have cloned the homologue of hb from the flour beetle Tribolium and show that, on the basis of its expression pattern, most of its functions seem to be conserved between these two species. Like Drosophila, Tribolium has a maternal hb expression that appears to be under translational control by a factor at the posterior pole of the embryo. The maternal expression is followed by a zygotic expression in the region of the developing head and thoracic segments. During germ band extension, a posterior expression domain appears that is likely to be homologous to the posterior blastoderm expression of hb in Drosophila. These observations suggest that hb may have the same functions in early Drosophila and Tribolium development, despite the different types of embryogenesis in these two species (long versus short germ development). One differing aspect of hb expression in Tribolium concerns a structure that is not present in Drosophila, namely the serosa. An hb expression domain at the anterior pole precisely demarcates the border between the extraembryonic serosa and the embryonic field in the Tribolium embryo at an early stage, and hb protein remains expressed in the serosa cells until the end of embryogenesis.

Amino Acid Sequence↗
PubMed1995

Age-specific incidence of cancer in Kingston and St. Andrew, Jamaica, 1988-1992.

During the period 1988-1992, a total of 4,030 malignant neoplasms were recorded in Kingston and St. Andrew, Jamaica. These comprised 1,829 in males and 2,201 in females. Histological confirmation was obtained in 83.4%. The crude incidence rate for males was 128.5, and 136.2 for females. The age-standardized rates (ASR) were 179.9 for males and 166.1 for females. Age-specific rates by site, sex and age are tabulated. Attention is drawn to increased incidence for cancers of prostate, larynx, bronchus and non-Hodgkin's lymphoma in males. There was also an increase in female breast cancer (crude rate 36.0; ASR 47.1). Invasive cervix cancer has shown no significant change in incidence. Neoplasms of the body of the uterus have increased (crude rate 7.6; ASR 9.5). The rise in cancer of breast and body of uterus suggests that the influence of exogenous oestrogens should be considered.

Adolescent↗
PubMed1994

[Hepatitis C virus infection in patients with porphyria].

Hepatitis C virus antibodies were studied in sera coming from 39 patients with porphyria (cutanea tarda in 17, variegate in 8, intermittent acute in 4, coproporphyria in 2 and protoporphyria in 8). Nine of 17 patients with porphyria cutanea tarda had positive antibodies, but none of the patients with other types of porphyria. All subjects with porphyria cutanea tarda had histological or laboratory liver abnormalities. There was no relationship between the presence of antibodies and frequency of alcoholism, diabetes, or carbohydrate intolerance. Family background of porphyria was significantly less frequent among patients with positive hepatitis C virus antibodies. In 13 patients, a liver biopsy was performed, always showing signs of chronic hepatitis, whose magnitude was higher in those with positive antibodies. It is concluded that, as reported previously, hepatitis C virus may be an activating factor for porphyria cutanea tarda or may potentiate its accompanying liver disease.

Enzyme-Linked Immunosorbent Assay↗