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C Contant

Publications and source records attributed to C Contant.

31 records · Page 2Linked to original sources
PubMed1996

Decision making for the surgical management of aortic coarctation associated with ventricular septal defect.

Coarctation of the aorta and associated ventricular septal defect may be repaired simultaneously or by initial coarctation repair with or without banding of the pulmonary artery. The question is whether specific preoperative criteria can enable the surgeon to choose the optimal surgical management. Between 1980 and 1993, 80 infants younger than 3 months with coarctation and ventricular septal defect were treated surgically. In 64 infants (multistage group), simple coarctation repair was performed through a posterolateral approach, with concomitant banding of the pulmonary artery in 10 infants. Twenty ventricular septal defects were closed as a secondary procedure and four were closed as a tertiary procedure. Sixteen infants (single-stage group) underwent one-stage repair through an anterior midline approach. The total in-hospital mortality rate was 7.5%. Freedom from recoarctation after 5 years was 91.3% in the multistage group versus 60.0% in the single-stage group (p = 0.018). Freedom from secondary ventricular septal defect treatment in the multistage group after 5 years was 40.7%, versus 100% in the single-stage group (p = 0.016). Thirty-seven ventricular septal defects (47.8%) closed spontaneously. In particular, the preoperative left-to-right shunt and extension of the perimembranous VSD into the inlet or outlet were risk factors for the need for eventual surgical ventricular septal defect closure after initial coarctation repair. On the basis of these two risk factors, the probability of the need for eventual surgical treatment of ventricular septal defect after initial coarctation repair can be calculated. This policy offers a well-considered choice between single-stage and multistage repair, weighing the risk of secondary ventricular septal defect treatment versus the risk of recoarctation. Finally, the number of surgical procedures per infant will be as low as possible.

Aortic Coarctation↗
PubMed1995

Postoperative neurologic complications after open heart surgery on young infants.

OBJECTIVE: To ascertain the relation between postoperative neurologic complications and variables occurring before, during, and after hypothermic cardiopulmonary bypass surgery to correct congenital heart disease in young infants. DESIGN: Prospective analysis of mortality and neurologic morbidity before hospital discharge; systematic comparison with patient characteristics, metabolic status, surgery variables; and preoperative neurologic findings of the patients. SETTING: Intensive care unit in tertiary care center. PATIENTS: Consecutive sample of 91 full-term infants who underwent 100 operations between January 1989 through December 1992. Nine infants had more than one operation during the study period. MAIN OUTCOME MEASURES: Levels of alertness, tone, focal signs, dyskinesia, pyramidal signs, seizures, and death. RESULTS: Reduced level of alertness at discharge from the hospital in 19% of patients; seizures in 15% (70% focal); severe hypotonia in 11% before surgery, and in 7% at discharge from hospital; generalized pyramidal findings in six (7%); asymmetry of tone in 5%; and chorea that did not persist in 11%. Results of cranial ultrasound tests were abnormal in 20% of patients. Of these those with abnormal cranial ultrasound examinations 55% were abnormal before surgery. Overall mortality was 18%. Of the patients who died, 59% had interrupted aortic arch or hypoplastic left heart syndrome. Mortality for patients with these lesions was 40%. Alertness (P = .005), chorea (P = .03), and hypotonia (P = .02) were associated with duration of deep hypothermia longer than 60 minutes. No association was found among other outcomes and study variables, except the relation between severe left-sided heart lesions and mortality. CONCLUSIONS: Mortality and neurologic morbidity after open heart surgery on young infants may be due to several factors, including type of lesion, preexisting brain abnormalities, duration of deep hypothermia, and strokes.

Brain↗
PubMed1995

Tremor and longevity in relatives of patients with Parkinson's disease, essential tremor, and control subjects.

To study the relation between essential tremor (ET) and Parkinson's disease (PD), we compared the frequency of familial tremor in relatives of patients with PD (N = 391), ET (N = 140), and the combination of ET and PD (N = 125) with the frequency in patients with progressive supranuclear palsy (PSP) (N = 99) and normal age-matched controls (N = 104). Tremor was present in 96 (5.1%) of 1,874 parents and siblings of patients with PD, 152 of 650 (23.4%) relatives of patients with ET, 91 (20.7%) of 439 relatives of patients with ET-PD, 12 of 462 (2.6%) relatives of patients with PSP, and 10 of 448 (2.2%) relatives of normal controls. The high frequency of familial tremor among relatives of patients with PD, and especially those with the ET-PD combination, compared with relatives of patients with PSP or of normal controls suggests that there is an association of PD and familial tremor. Since the most common form of familial tremor is ET, our study provides support for the notion that ET and PD are pathogenetically related. We also found that parents with tremor lived on the average 9.2 years longer than those without tremor. The association of familial tremor with significantly increased longevity suggests that familial tremor confers some anti-aging influence. Alternatively, tremor may be a simple byproduct of the aging process.

Adult↗
PubMed1994

Hemophilia growth and development study: baseline neurodevelopmental findings.

Reported baseline findings from the neurological assessment component of the Hemophilia Growth and Development Study (HGDS). HIV-positive (HIV+; n = 207) and HIV-negative (HIV-; n = 126) young males with hemophilia ages 6 to 18 years, were enrolled in a prospective study of their growth and development. At baseline, HIV+ and HIV- subjects were not significantly different in test performance. The number of subjects exhibiting below-average performance in three or more areas assessed was about 25% overall. For both groups, mean test scores were within the average range. Academic and adaptive skills were lower than expected based on mean IQ scores, and more behavioral/emotional problems than expected were reported by parents. Absolute CD4 cell counts per mm3 were not related to neuropsychological performance at baseline. Results suggest that the subjects with HIV were relatively free of HIV-related neuropsychological impairment at baseline and that observed differences from a general population reflect effects of hemophilia as a chronic illness.

Adolescent↗
PubMed1994

Atrial natriuretic factor, angiotensin II, and the slow component of renal autoregulation.

Autoregulation of renal blood flow is highly efficient and is mediated partly by tubuloglomerular feedback (TGF), which couples regulation of blood flow to that of sodium excretion. Atrial natriuretic factor (ANF) dilates preglomerular resistance vessels, in which autoregulation occurs, and has been reported to inhibit TGF. This study addressed potential actions of ANF on the slow, TGF-mediated, component of autoregulation. Renal blood flow was measured by an electromagnetic flow probe in Sprague-Dawley rats anesthetized by halothane or isoflurane while renal perfusion pressure was manipulated by a servo-controlled clamp placed on the aorta between the renal arteries. Progressive reduction of perfusion pressure to 60 mmHg (1 mmHg = 133.3 Pa) induced resetting of autoregulation to operate at the reduced pressure and to defend lower renal blood flow. Infusion of ANF at a dose shown to reliably increase sodium excretion did not affect autoregulation or its resetting. Because resetting is angiotensin II dependent, the converting enzyme inhibitor Enalaprilat was used to provide angiotensin II blockade. As expected, autoregulation did not reset to operate at reduced perfusion pressure. Again ANF was without effect. In a third experiment, relaxation of resistance was assessed in response to repeated steps of perfusion pressure between 65 and 75 mmHg. Time constants of constriction and dilatation were recovered by fitting to a single exponential before and during ANF infusion. Time constants ranged form 0.045 to 0.055 Hz, were consistent with operation of TGF, were not different for constriction or dilatation, and were unaltered by ANF; nor did ANF affect the magnitude of constriction or dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1993

A multicenter study of viral hepatitis in a United States hemophilic population.

Hemophilia A and B patients seen at nine US regional treatment centers were tested for serologic markers of hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis delta virus (HDV) during 1987 and 1988. Because human immunodeficiency virus (HIV) infection, a potentially confounding variable, was present in 53% of the group, the population was divided by HIV status for analysis purposes. In the HIV-positive group (N = 382), less than 1% had not been infected with HBV, HCV, or HDV, whereas 75% had evidence of infection with HBV and 98% with HCV. HBsAg, a marker of active HBV infection, was present in 12% of subjects; 96% of these were HCV positive. Anti-HDV was detected in 35 subjects (9.1%); all were anti-HBc positive. Ten of the 35 (29%) also were positive for IgM anti-HDV, indicating current infection. All 10 were HBsAg positive and 7 of the 9 tested were HDV RNA positive. Severe/moderate hemophilia B patients were more likely to have experienced an HBV infection and to be anti-HDV positive than were similar hemophilia A patients (22% v 8%, P < .05). In the HIV-negative group (N = 345), the subjects were younger and had less severe hemophilia than the HIV-positive patients. No evidence of HBV, HCV, or HDV infection was found in 18%, whereas 33% had experienced HBV infection and 79% were anti-HCV positive. Within this group, 4% were HBsAg positive. All 13 subjects with anti-HDV (4% of the HIV-negative group) also possessed anti-HBc. One (7.7%) was IgM anti-HDV positive and the serum from another contained HDV RNA. Both of these individuals were HBsAg positive. As in the HIV-positive group, severe/moderate hemophilia B patients were more likely to be HBV and HDV positive than were hemophilia A patients (9% v 3%, P < .05). A prevalence study of viral hepatitis in a large US hemophilic population showed that active infection with HCV is common, occurring in 89% of all study patients regardless of HIV status. Evidence of active HBV infection was found in 8%; 19% of these were actively infected with HDV. HDV was more common in hemophilia B patients after controlling for disease severity.

Adult↗
PubMed1992

Bio-effects of high magnetic fields: a study using a simple animal model.

The desire to do clinical imaging and spectroscopy at magnetic field strengths greater than 2 Tesla (T) necessitates investigation of possible bioeffects at these high fields. A simple T-maze was utilized to evaluate the aversive effects of exposure to three levels of static magnetic field (0, 1.5, and 4 T). The right arm of the maze extended into the center of a 30-cm horizontal bore magnet, while the left arm extended into a mock magnet bore with the same dimensions. The self-shielded design of the magnet reduces the fringe field to zero within 1 m of the bore, placing the start box of the maze outside the 5-G line of the magnet. Each rat performed a total of ten trials at each level of magnetic field strength. A follow-up subset was run at 4 T with the maze reversed. At 0 T, the rats entered the magnet freely. No significant differences from the control were observed at 1.5 T. At 4 T, however, in 97% of the trials the rats would not enter the magnet. In the maze-reversed subset a majority of the rats turned toward the magnet, indicating that they had learned an aversive response from the previous trials at 4 T. However, in only 4 decisions out of 58 did the rats actually enter the magnet. Eighteen decisions to turn around were made at the edge of the magnet in a region of strong field gradients (up to 13 T/m) and a field strength up to 1.75 T.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Air pollution and lung cancer mortality in Harris County, Texas, 1979-1981.

Elevated lung cancer mortality rates in Harris County, Texas compared with other US counties and previously published reports that suggested a causal relation between air pollution and lung cancer in Houston prompted this ecologic analysis. A weighted regression analysis was used to examine the air pollution-lung cancer mortality relation for white males in Harris County, Texas, 1979-1981. The regression model included the following census tract-specific characteristics: median age for white males, two social and demographic factors not strongly correlated with pollution (family life cycle and migration), an age-dependent smoking index, and a pollution measure based on total suspended particulates. This model indicated a statistically significant contribution of the pollution measure in explaining the intracounty variation in lung cancer mortality rates. The relation between air pollution and lung cancer mortality, however, appeared to be highly dependent on which social and demographic factors were selected for inclusion in the analysis. Air pollution was not demonstrated to be a strong determinant of lung cancer mortality in this study in that the presence of air pollution accounted for less than 5% of the total variation in intraurban lung cancer mortality. In addition, the interpretation of geographic analysis must be guarded due to the introduction of potential bias due to aggregation. The hypothesis that air pollution is contributory to lung cancer cannot be tested until other, stronger individual risk factors for lung cancer can be better measured and controlled in studies of this association.

Adult↗
PubMedDate not supplied

Improvement of gene therapy for ovarian cancer by using acyclovir instead of ganciclovir in adenovirus mediated thymidine kinase gene therapy.

Adenovirus(ADV) mediated thymidine kinase(TK) gene therapy followed by ganciclovir(GCV) administration is widely used in different types of cancer. ACV shares the same mechanism of selective cell killing in ADV/TK positive cells as GCV and can be used at 4.5 times higher doses in patients without significant side effects. An increased dose of TK substrate is associated with improved bystander effect and more efficient cell killing. Toxicity and cell killing efficacy were assessed using a 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium bromide(MTT) based assay in three ovarian cancer cell lines with different proliferation patterns. At the same concentration, equal or higher cell killing efficacy and bystander effect were observed using ACV rather than GCV. 2.5 and 5 times (25 micrograms/ml and 50 micrograms/ml) higher concentrations of ACV always resulted in more effective cell killing than GCV (10 micrograms/ml, P < 0.01). Our data indicate that replacing GCV with ACV in the ADV-TK gene therapy may increase the treatment effect without increasing toxicity.

Acyclovir↗