PubMed Health⌕ Search

Biomedical subjects

D Graf

Publications and source records attributed to D Graf.

At least 37 records · Page 2Linked to original sources
PubMed1990

Pulmonary artery balloon counterpulsation for right ventricular failure after right ventriculotomy in the swine.

To assess the efficacy of intrapulmonary balloon counterpulsation in the management of right ventricular failure after right ventriculotomy, we undertook an experimental study in a swine model. To mimic the clinical settings more closely, (1) we left the automatic control of the heart intact (2) did not use cardiopulmonary bypass to support the left side of the heart, and (3) induced right ventricular failure by means of a generous surgical incision (50% to 70% of the anterior wall) of the right ventricle. The criteria set for right ventricular failure were (1) 50% increase in right ventricular end-diastolic pressure, (2) 30% decrease in mean arterial pressure, and (3) 30% decrease in cardiac output. Right ventricular failure was attained in all animals studied: A 230% increase in right ventricular end-diastolic pressure, a 43% decrease in cardiac output, and a 34% decrease in mean arterial pressure were evident after the right ventriculotomy. A specially designed intrapulmonary balloon catheter (Datascope Corp., Oakland, N.J.) was placed into the left pulmonary artery through the right ventricular outflow tract. A Datascope console was used for counterpulsation. Effects of counterpulsation for 40 minutes in a 1:1 mode were assessed after surgical induction of right ventricular failure in 14 swine. Each animal served as its own control. The mean hemodynamic changes are outlined: Right ventricular end-diastolic pressure decreased by 48.9% (p = 0.01). Mean arterial pressure increased by 68.8% (p = 0.01) and cardiac output by 44.2% (p = 0.01). Histologic studies disclosed no morphologic damage to the pulmonary artery or valve in the specimens analyzed. In addition, these results were compared with those in a second group of seven swine in which right ventricular failure was induced by right ventriculotomy and a balloon was placed into the left pulmonary artery but not activated. These results of short-term counterpulsation should be evaluated in a longer term model so as to mimic more closely the clinical setting. If the hemodynamic benefits are duplicated, intrapulmonary balloon counterpulsation should be considered as a simple, effective device when right ventricular failure develops after right ventriculotomy. It effectively improves right ventricular function without damaging the pulmonary artery or valve.

Animals↗
PubMed1989

Factors determining in-hospital or late survival after aortic valve replacement.

To ascertain incremental risk factors for in-hospital and late mortality of patients undergoing AVR with the bovine pericardial valve, multiple variables were analyzed in a group of 240 patients undergoing AVR between 1977 and 1983. Follow-up totaled 12,023 patient-months (mean, 52.7 +/- 1.7 patient-months) and was 100 percent complete. Univariate analysis of incremental risk factors for in-hospital mortality identified the following: age over 60 years (p = 0.015); and advanced preoperative NYHA class (p = 0.003). Multivariate analysis of risk factors for in-hospital mortality identified the following: age (p = 0.038); NYHA class (p = 0.018); and year of operation (p = 0.049). Incremental risk factors for late mortality were identified as age (p = 0.003), year of operation (p = 0.003), concomitant procedure (p = 0.047), and valvular lesion (regurgitation) (p = 0.053). Actuarial survival of patients (+/- SE) was 87 +/- 2 percent, 75 +/- 3 percent, and 61 +/- 5 percent at 2, 5, and 8.7 years, respectively. The actuarial survival of patients experiencing valve-related events was 62.6 +/- 10.1 percent at 8.7 years, compared to 55.4 +/- 7 percent for those who did not (p = 0.38).

Actuarial Analysis↗
PubMed1989

[A drowning accident of long duration with deep hypothermia and rewarming with extracorporeal circulation. A report of 2 patients].

Two nearly drowned, 2 9/12 and 3 6/12 years old boys with profound hypothermia were admitted to our pediatric intensive care unit with all signs of clinical death. Both patients could be rewarmed and oxygenated by extracorporeal circulation. One of them died 36 hours after the accident with severe brain edema. The second one survived without any defect. Rewarming of cold-water nearly-drowned patients by extra-corporeal circulation seems to be a very effective way of treatment.

Accidents↗
PubMed1988

Isolation of four rat creatine kinase genes and identification of multiple potential promoter sequences within the rat brain creatine kinase promoter region.

Rat genes encoding muscle creatine kinase (gene ckm) and brain creatine kinase (gene ckb) have been cloned. The two genes have an identical intron-exon distribution, although introns of the ckb gene are much smaller than those for ckm. The complete nucleotide sequence has been determined for the ckb gene. 5'-Flanking sequences have been compared for both ckm and ckb. The ckb gene has a structurally complex 5'-flanking region with multiple TATA and CAAT sequences suggesting that the gene may contain overlapping promoter elements. Examination of ckb RNA from brain tissue provides no evidence for the existence of more than one set of transcriptional start points. The ckm and ckb genes show little homology in the 5'-flanking regions, although we observed some sequence conservation in the regions immediately surrounding the CAAT and TATA sequences. The rat genome also contains two other creatine kinase-like sequences which may represent processed pseudogenes or mitochondrial creatine kinase.

Amino Acid Sequence↗
PubMed1988

Opticon flutter.

Explore the source record for details and available documents.

Aged↗
PubMed1988

Estrogen and progesterone receptors as prognostic factors in breast cancer.

The relation between estrogen receptors (ER) and/or progesterone receptors (PgR) and some clinical factors such as tumor size, axillary node involvement, histological tumor grade, and disease-free interval (DFI) in 500 patients with operable (TNM stage I-III) breast cancer was studied. ER-positive (ER+) tumors were commoner in older patients, whereas PgR-positive (PgR+) tumors were similarly distributed within the age groups. The concentration of ER+ protein also increased with age in contrast to PgR+ protein concentration. However, receptor status was not associated with menopausal status independently of age. Axillary node involvement influenced neither ER nor PgR status, but there was a statistically significant relation between tumor size and positivity of ER or PgR. There was no association between histologic tumor grade and either steroid receptor phenotype. DFI was longer in patients with ER+ than those with ER- tumors, independently of axillary nodal status. The positivity of PgR in patients with ER+ tumors contributed to an even longer DFI, suggesting that the combination of ER/PgR is a better indicator of DFI than ER or PgR alone.

Adult↗
PubMed1988

Pulmonary homograft implantation for ventricular outflow tract reconstruction: early phase results.

The pulmonary valve homograft (PH) has been reported to have potential advantages over the aortic valve homograft, including a larger diameter, a thinner wall, and decreased intrinsic calcification. From January 16, 1986, to July 14, 1987, eight consecutive patients underwent repair of congenital cardiac anomalies using a cryopreserved PH. Patients ranged in age from 18 months to 32 years. Diagnoses included tetralogy of Fallot with pulmonary atresia (3 patients); tetralogy with absent pulmonary valve (1 patient); corrected transposition with pulmonic stenosis (1 patient); transposition of the great arteries, ventricular septal defect, and pulmonic stenosis (2 patients); and double-outlet right ventricle with pulmonic stenosis (1 patient). The PH was implanted orthotopically in the patient with absent pulmonary valve, and in the other 7 it was placed as a valved extracardiac conduit. Two of the tetralogy patients with severe bifurcational pulmonary stenosis and another with nonconfluent pulmonary arteries and origin of the left pulmonary artery from a patent ductus arteriosus had their repairs facilitated using the branching pulmonary arterial portion of the PH. There were no hospital or posthospital deaths. Postrepair right ventricular to left ventricular systolic pressure ratios were a mean of 0.35 at 18 hours postoperatively (range, 0.21-0.61). All patients were studied with Doppler and echocardiography after repair. The mean gradient across the PH was 9 mm Hg (range, 2-27 mm Hg), and no pulmonary valve incompetence was present. One patient (12.5%) required reoperation seven months after repair for conduit revision due to compression by the sternum and is now well.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

The Ross operation: the autologous pulmonary valve in the aortic position.

Aortic valve replacement (AVR) with a pulmonary valve autograft (PVA) was first reported by Donald N. Ross (DNR) in 1967. The expectation of this procedure was to avoid degenerative changes seen in other biological tissue valves such as calcification, attenuation, and rupture of the leaflets. Recent reports by the original investigator's group have confirmed the lack of degenerative changes in PVA. To corroborate their conclusions, the fate of 12 patients undergoing AVR with PVA by one of us (LGL) has been ascertained. From March 1969 to June 1971, 12 patients underwent AVR with PVA. The right ventricular outflow tract (RVOT) was reconstructed with an aortic homograft valved conduit. The mean age was 42.7 years (range 21 to 52 years). The mean follow-up for 11 hospital survivors is 12.4 years. Three PVA have been replaced; one following infective endocarditis at 13 years, and two at 15 and 73 months due to technical malalignment. There was no evidence of PVA degeneration during histological examination of these explanted PVAs. Six patients are alive and retain the original PVA at 12 years (55%). This analysis corroborates the conclusions of the DNR report and strongly suggests an immunological mechanism in the process of calcification of other biological tissue valves. The Ross operation is advocated for AVR in young patients as valve durability is of paramount importance especially in this group.

Adult↗
PubMed1988

Morbidity following the Ross operation.

Aortic valve replacement (AVR) with a pulmonary valve autograft (PVA) was first reported by Donald N. Ross in 1967. The expectation of this procedure was to avoid degenerative changes seen in other biological tissue valves such as calcification, attenuation, and rupture of the leaflets. Recent reports by the original investigator's group have confirmed the lack of degenerative changes in PVA. To corroborate their conclusions, the fate of 12 patients undergoing AVR with PVA by Dr. Gonzalez-Lavin has been ascertained. From March 1969 to June 1971, 12 patients underwent AVR with PVA. The right ventricular outflow tract (RVOT) was reconstructed with an aortic homograft valved conduit. The mean age was 42.7 years (range 21 to 52 years). The mean follow-up for 11 hospital survivors is 12.4 years. Three PVAs have been replaced; one following infective endocarditis at 13 years, and two at 15 and 73 months due to technical malalignment. There was no evidence of PVA degeneration during histologic examination of these explanted PVA. Six patients are alive and retain the original PVA at 12 years (55%). This analysis corroborates the conclusions of Dr. Ross and strongly suggests an immunological mechanism in the process of calcification of other biological tissue valves. The Ross operation is believed to be the preferred method of AVR in young patients.

Adult↗
PubMed1988

Homograft valve preparation and predicting viability at implantation.

An experimental study was performed using C14 proline uptake in order to: (1) assess the effects of current sterilization and storage methods on fibroblast viability, and (2) establish a control tissue that could be used to determine viability of each homograft valve at the time of implantation in the clinical setting. The results were expressed as disintegrations per minute per milligram of tissue (DPM/mg). Swine aortic (AV), pulmonary (PV), and tricuspid leaflets (TV), and adjacent AV and PV arterial wall were procured sterile and subjected to routine sterilization and storage. Thirty samples of AV were analyzed for incorporation of labeled proline at procurement (208 +/- 7 DPM/mg), following 48-hour antibiotic exposure (87 +/- 6 DPM/mg, P less than .0001), and following controlled rate cryopreservation and storage for 12 days at -80 degrees C (78 +/- 8 DPM/mg, P = .42). Proline uptake of the other tissues at the same intervals disclosed that only the TV resulted in the same degree of viability at implantation (AV 78 +/- 8, PV 68 +/- 3, TV 75 +/- 2, P = NS). The homograft valves were obtained under sterile conditions from brain dead, multiorgan donors (homovital). It has been postulated that these valves are sterile and ready for implantation. Of 17 homovital valves cultured at procurement, 9 had positive cultures within 48 hours (53%). We conclude that: (1) the TV can be processed as a control tissue with each homograft and then utilized to predict viability at the time of implantation in the clinical setting; (2) antibiotic exposure is an essential step in the preparation of all homografts, however, modification of the antibiotic solution is necessary.

Carbon Radioisotopes↗
PubMed1988

[Perforation of the large intestine by a contrast medium enema with barium].

This is a report about five patients who suffered a perforation of the colon during a barium-sulfate enema. In one case, barium leaked into the intraperitoneal cavity causing a barium peritonitis. In the other four cases, leakage into the retroperitoneal cavity occurred. All patients underwent surgical removal and drainage of the barium-sulfate and subsequently required a colostomy. In two cases a bowel resection was additionally performed. In one case the defect re-sutured. Antibiotic therapy was included in all cases. All patients survived the incident and were discharged between 20 days and four months postoperatively. Publications and personal experience led us to manage intraperitoneal or large retroperitoneal perforations by prompt laparotomy with removal of barium and faeces. A proximal colostomy is also required. In smaller retroperitoneal perforations conservative management is feasible, however, if the patient's condition deteriorates, they should be treated as recommended for an intraperitoneal perforation.

Aged↗
PubMed1987

Determining viability of fresh or cryopreserved homograft valves at implantation.

Studies of homograft valves in the past two decades have suggested that "viable" valves, i.e., those maintaining chemical and structural integrity of their leaflet intercellular matrix, have a better long-term function than nonviable valves. The most effective qualitative methods of assessing leaflet viability involve destruction of the valve leaflets; thus, these methods have been limited to random use in selected valves. A study was conducted in swine in an attempt to establish a control tissue which could be tested in place of the homograft leaflets, thereby determining viability levels of every valve clinically implanted and correlating the results with long-term clinical function. Thirty samples each of the aortic and pulmonary artery wall and tricuspid leaflet were compared with aortic and pulmonary leaflets. Utilizing the technique of C14-proline uptake, viability was assessed at procurement, following sterilization, and following cryopreservation and short-term storage. The tricuspid leaflet was found to retain the same level of viability as the aortic and pulmonary leaflets before and after the cryopreservation period. It was concluded that the tricuspid leaflet could be utilized as the control tissue.

Animals↗
PubMed1986

[Antibiotic treatment of perforated appendicitis in childhood--a prospective study].

A prospective randomised study (I) was carried out on 130 children undergoing laparotomy for perforated appendicitis. The present study evaluates the therapeutic effectiveness of different antibiotic regimens in modifying the rate of post-operative complications (intraabdominal abscess, ileus, wound infiltration or abscess). During the first year of this study two treatment groups were used. Group A consisted of 29 children treated with Sulfometrol/Trimethoprim; the rate of postoperative complications was 44.8%. Group B consisted of 36 children treated with mezlocillin, the rate of complications being 13.8%. However, the same treatment with mezlocillin during the second year of the prospective study showed an increase of this rte to 39% (28 children--group C). The final group of 37 children was treated during the second year with mezlocillin and metronidazole (group D). The postoperative rate of complications was 10.8%. A retrospective analysis of further 80 children (study II) with perforated appendicitis treated with mezlocillin and metronidazole showed a consistent low rate of postoperative complications at 10.2%. In 6.8% of children studied, an operative intervention was necessary (four cases of ileus, four wound abscesses). The mean postoperative hospitalisation period decreased from 22.7 days in group A to 15.2 days in group D and finally to 14 days in study II. The present study shows that an effective and persistent attenuation of the rate of postoperative complications after perforated appendicitis in children depends on an early onset of therapy and on the appropriate choice of antibiotic drugs that are effective against aerobic and anaerobic microorganisms.

Anti-Bacterial Agents↗
PubMed1985

Dynamic responses to intravenous urapidil and dihydralazine in normal subjects.

Hemodynamic responses after urapidil were compared with those after dihydralazine in placebo-controlled, double-blind studies after cumulative intravenous doses. We recorded heart rate, blood pressure, systolic time intervals corrected for heart rate (electromechanical systole and preejection period), electrical impedance cardiography [(dZ/dt)/RZ index and mean electrical thorax impedance], and M-mode echocardiogram (end-systolic and -diastolic diameters, end-systolic wall stress, fractional shortening, and cardiac output). Both drugs induced dose-dependent reductions in total peripheral resistance, which resulted in reduction in left ventricular end-systolic wall stress and increases in heart rate (limited at +10 bpm with urapidil), fractional shortening, cardiac output, and the (dZ/dt)/RZ index. With each drug, diastolic blood pressure fell by 5 mm Hg, the corrected preejection period shortened (dihydralazine greater than urapidil), the corrected electromechanical systole did not change, and mean electrical thorax impedance rose with urapidil. The spectrum of effects indicates that both drugs reduce left ventricular afterload, thereby increasing left ventricular pump performance. Urapidil also exerts some preload reduction.

Adult↗