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Biomedical subjects

R A Ott

Publications and source records attributed to R A Ott.

At least 37 records · Page 2Linked to original sources
PubMed1987

Selection of patients for cardiac transplantation.

Selection of potential cardiac recipients is not a simple process. Identification of patients who are declining from end-stage cardiac disease and may be expected to die within 12 months or less and deciding which of a number of cardiac invalids are reasonable candidates for cardiac transplantation involves prognostication as well as a working knowledge of the expected benefits and survival rates in cardiac transplantation. Screening by means of the currently accepted contraindications for cardiac transplantation is somewhat more difficult in 1986 than it was 10 years ago when these contraindications were changing less rapidly. However, for optimal use of the limited supply of donor organs and maintenance of reasonable survival rates such screening is absolutely necessary. A second area of restriction that is less approachable by the physician is that of financial limitations. It would appear that the working poor and lower middle class may be deprived of the opportunity for cardiac transplantation much as they are deprived of the opportunity for optimal medical care in our society today.

Age Factors↗
PubMed1987

The incidence of thyroid carcinoma in Hashimoto's thyroiditis.

The incidence of thyroid carcinoma in Hashimoto's thyroiditis has been a widely debated issue. Previous authors have reported on this topic by analyzing series of patients with Hashimoto's thyroiditis or patients with thyroid carcinoma, but not both of those populations in the same series. The population consists of a consecutive series of 800 patients operated on for thyroid nodules not associated with a radiation history. Among 161 patients with the diagnosis of thyroid carcinoma, 61 (38%) had coexistent Hashimoto's thyroiditis. In comparison, among 161 sex- and age-matched patients with colloid nodules in the same population, 18 (11%) had Hashimoto's thyroiditis. Furthermore, in the series as a whole, the incidence of Hashimoto's thyroiditis in 423 patients with colloid nodules was 10 per cent. From the perspective of the Hashimoto's thyroiditis population in the same series of 800 thyroidectomies, among 267 patients with Hashimoto's thyroiditis 61 (23%) had coexistent carcinoma. In comparison, among 267 age- and sex-matched patients with colloid nodules there were only ten coexistent carcinomas for an incidence of 4 per cent. The high incidence of carcinoma of the thyroid in Hashimoto's thyroiditis lends credence to the hypothesis that Hashimoto's thyroiditis is a predisposing factor in the development of thyroid carcinoma.

Adolescent↗
PubMed1987

Radioiodine sensitivity of parafollicular C cells in aged Long-Evans rats.

An earlier study from our laboratory demonstrated that the incidence of thyroid C cell neoplasia in aging Long-Evans rats was high. When radioactive iodine was administered to 8-week-old Long-Evans rats, this incidence was reduced, although thyroid follicular cell neoplasia was increased. The aim of this study was to determine whether iodine-131 (131I) administered to an aged population of Long-Evans rats with established C cell hyperplasia would have a C cell ablative effect as pronounced as that observed in studies of young rats. For this study, 180 18-month-old Long-Evans rats (90 male and 90 female) were used. Baseline serum calcitonin levels were determined, and control and experimental groups containing equal numbers of animals were designated. 131I was administered by intraperitoneal injection to the experimental group, while equal volumes of saline solution were given to the control group. Blood samples for determination of serum calcitonin levels were obtained at 6-week intervals until the rats were 24 months old. Thyroid glands were then removed, and tissues were fixed, sectioned, and stained with hematoxylin and eosin and with peroxidase-antiperoxidase (PAP) using an anticalcitonin antibody. Examination of thyroid tissues showed that the incidence of C cell neoplasia was significantly reduced in irradiated animals as compared with nonirradiated controls (chi 2 analysis, p less than 0.05). PAP staining demonstrated diminished intracytoplasmic calcitonin in the radiation-treated group. Analysis of serum calcitonin levels over time showed significantly lower levels in the irradiated rat group than in the nonirradiated group (p less than 0.006).

Aging↗
PubMed1986

Thromboembolic complications of the Jarvik-7 total artificial heart: case report.

The Jarvik-7 total artificial heart (TAH) has now been implanted in seven patients, with four (57%) suffering cerebral embolic events. Functional recovery in two patients was impaired by subsequent intracranial hemorrhage from anticoagulant therapy. The findings of a Jarvik-7 TAH explanted following a cerebral embolus are reported here. Thrombotic deposition was seen in the inner crevice formed between the two components of the aortic quick connector. In addition, deposition was seen around all four valves in the crevice formed between the valve ring and the plastic valve housing. On the atrioventricular valves, the deposition in this crevice was most severe on the outflow surface adjacent to the minor flow orifice. On the pulmonic valve, deposition was seen around the entire circumference of both the inflow and the outflow crevices. No thrombi were seen on the diaphragm, the diaphragm-housing junction, or the housing of the left ventricle. Hypercoagulability of the patient's blood gradually developed during implant, reaching a maximum on the evening before the clinical embolus. Increasing resistance to heparin was also demonstrated by in vitro testing.

Adult↗
PubMed1986

Cardiac transplant patient at one year. Cyclosporine vs conventional immunosuppression.

From March 1, 1979 thru September 30, 1984 we performed 56 cardiac transplants (Tx). The first 32 patients received conventional immunosuppression therapy consisting of azathioprine/prednisone (I/P), while the subsequent 24 patients received cyclosporine/prednisone (C/P). Twenty-one of 32 I/P patients ages 39 +/- 3 years (SEM), and 16 of 24 eligible C/P patients ages 36 +/- 3 years, survived one year with follow-up through September 30, 1985. The one year post-transplant course of these 37 patients was evaluated by chart review. While donor ages are similar, ischemic time was shorter in the conventionally treated patients. The initial hospital stay for I/P vs C/P was 67 +/- 6 vs 33 +/- 3 days (p less than .05), at a total cost of $49,900 +/- $5,800 vs $53,800 +/- $10,000. During the first year following transplantation, the I/P patients required an additional 34 +/- 7 days of hospitalization, while C/P patients required 16 +/- 10 days. Over the first year, the number of infections and rejections differed at 2.8 +/- 0.6 per I/P patient vs 1.2 +/- 0.3 per C/P patient, and 2.5 +/- 0.4 per patient vs 1.5 +/- 0.3 per patient respectively (p less than .05). Renal function test results were better in the I/P group. Results of cardiac catheterization performed at one year were similar except for cardiac index and stroke volume index, both being higher in the C/P group. Coronary anatomy was considered normal in all. These data indicate that while overall survival is similar, a shortened post-transplant hospital course with fewer necessary hospitalizations, rejection episodes and infection episodes characterizes the first year in survivors receiving C/P immunosuppression. While both groups had multiple hemo-dynamic abnormalities as compared to normal subjects, cardiac index and stroke volume index were improved in the C/P group. Therapy with C/P represents an advance in immunosuppression for cardiac transplantation as compared to I/P; however, decreased renal function and diastolic hypertension were problems in the C/P group.

Arizona↗
PubMed1985

Operative risk factors associated with unstable angina pectoris.

We performed a prospective study in 207 patients with unstable angina pectoris (UA) to identify factors associated with operative mortality (OM) and perioperative myocardial infarction (MI) from myocardial revascularization. The OM was 3.9% (8/207) and the incidence of MI was 11% (23/207). Clinical variables (age, prior MI, electrocardiographic evidence, symptoms, left ventricular function) and operative variables (incomplete revascularization, cardiopulmonary bypass time, cross-clamp time) did not correlate with OM or MI. Operative mortality was associated with critical triple-vessel disease, but not left main coronary artery disease, and accounted for seven of the eight deaths (P less than .01). Myocardial infarction was associated with elective surgery (22/167) as opposed to urgent surgery (1/40) (P less than .01). Therefore, patients with critical triple-vessel disease are the highest risk group for OM, and urgent operation seems to reduce the incidence of MI in patients with UA.

Aged↗
PubMed1985

Demonstration of both immunologically unique and common antigenic determinants in Dirofilaria immitis and Toxocara canis using monoclonal antibodies.

Using an ELISA system, the immunological cross-reactivity between D. immitis and T. canis has been, for the first time, examined on an individual clone-by-clone basis. This study offers a definitive demonstration of the presence of immunologically distinguishable species-specific non-crossreactive antigens and the presence of cross-reactive antigens in antigenic extracts obtained from adult D. immitis and T. canis.

Animals↗
PubMed1985

The incidence of thyroid carcinoma in patients with Hashimoto's thyroiditis and solitary cold nodules.

The reported incidence of thyroid carcinoma in Hashimoto's thyroiditis varies widely. For this reason the specific subpopulation of patients with Hashimoto's thyroiditis and a solitary cold nodule was analyzed. Between 1972 and 1984 we operated on 146 consecutive patients with solitary cold nodules and Hashimoto's thyroiditis. There were 47 carcinomas, for an incidence of 32%. The mean age of the 146 patients was 43 1/2 years (median 44 years), with 126 females and 20 males. There was a history of prior head and neck radiation exposure in 54 patients, with a 33% incidence of thyroid carcinoma. The 92 patients without a history of radiation exposure had a 31.5% incidence of carcinoma. The frequency of multicentricity (bilateralism) was 33% in the group that underwent radiation and 24% in the group that did not. To date, with a mean follow-up of 4.7 years, there have been no deaths and no evidence of recurrence. In conclusion, we report a 32% incidence of thyroid carcinoma in patients with Hashimoto's thyroiditis and a solitary cold nodule, with no apparent difference between the patients with or without a history of radiation exposure, although there was a higher incidence of bilateralism (33% versus 24%) in the carcinomas of the patients with a history of head and neck irradiation. We suggest that the operative management of these patients is total thyroidectomy for those with a history of head and neck radiation and thyroid lobectomy for patients with no history of radiation, followed by contralateral lobectomy if a carcinoma is demonstrated.

Adenocarcinoma↗
PubMed1984

Production and characterization of monoclonal antibody to gentamicin.

Splenocytes from BALB/c mice immunized with a gentamicin-hemocyanin conjugate were fused with X63-Ag8.653 murine myeloma cells to produce hybridomas that secreted monoclonal antibody to gentamicin. Sixteen positive clones were obtained. The monoclonal antibody chosen for a gentamicin immunoassay has been characterized with respect to class, subclass, type of light chain, electrophoretic homogeneity, and binding affinity. Gentamicin monoclonal antibody purified from mouse ascites fluid was analyzed by immunoelectrophoresis, double immunodiffusion, enzyme-linked immunosorbent assay (ELISA), and polyacrylamide gel electrophoresis (PAGE). The results show that the antibody is an IgG2a (kappa). Two bands were detected when the purified antibody was electrophoresed on polyacrylamide gels: a major band and a less mobile minor component (5.6% of the major band). Both were IgG2a (kappa). The major band contained antibody which bound 2.1 moles of the substrate-labeled gentamicin derivative, beta-galactosyl-umbelliferone sisomicin, per mole of IgG, whereas one mole of the minor band bound only 0.095 moles of the substrate-labeled conjugate. The antibody has an affinity constant of 1.22 X 10(10) M-1.

Animals↗
PubMed1984

Cardiac assist by extracorporeal membrane oxygenation with in-line left ventricular venting.

We have used a canine heart failure model and extracorporeal circulation to study the limitations of extracorporeal membrane oxygenation (ECMO) for the treatment of cardiac failure. ECMO does not routinely achieve total biventricular bypass and does not effectively decompress the failing left ventricle. The addition of an in-line left ventricular vent (ECMO-lv) provided total biventricular bypass and complete left ventricular decompression in every experiment. ECMO-lv merits consideration as a biventricular bypass system for total mechanical support of the failing heart.

Animals↗
PubMed1983

Gentamicin substrate-labeled fluorescent immunoassay containing monoclonal antibody.

The current substrate-labeled fluorescent immunoassay for gentamicin has been modified by substituting monoclonal antibodies for conventional antiserum to gentamicin. The standard curve generated with gentamicin monoclonal antibody was essentially linear from 0 to 12 micrograms/ml, could detect 0.4 micrograms of gentamicin per ml, and had overall intra- and interassay precision values (coefficients of variation) of 1.9 and 5.0%, respectively. The substrate-labeled fluorescent immunoassay produced with gentamicin monoclonal antibody gave results with clinical specimens comparable (r = 0.991) to those obtained with the commercially available substrate-labeled fluorescent immunoassay and also with an enzyme immunoassay, a radioimmunoassay, and a fluorescent immunoassay. This technologically state-of-the-art assay employs both a nonisotopic label and monoclonal antibodies. It offers excellent precision, sensitivity, lot-to-lot reproducibility, linearity, and reagent stability.

Antibodies, Monoclonal↗
PubMed1983

Left atrial-to-aortic assistance with in-line left ventricular venting.

Left atrial-to-aortic assistance (LA-A) has been employed for left ventricular failure (LVF) refractory to intra-aortic balloon counterpulsation. Although clinical success has been reported, LA-A is limited by incomplete left ventricular (LV) decompression. We have developed a method to augment LA-A with an in-line LV apical vent (LA-lv-A). LVF was produced in 12 dogs by ligation of the circumflex coronary artery. Circulatory assistance was established with LA (28-32 Fr), LV apex (12-14 Fr) and femoral artery cannulation and a centrifugal pump. LA-A assistance was compared to LA-lv-A. Left atrial pressure was reduced from 10 +/- 3 torr to 5 +/- 3 torr (p less than 0.001), left ventricular systolic pressure was reduced from 48 +/- 4 torr to 9 +/- 2 torr (p less than 0.001) and left ventricular end-diastolic pressure was reduced from 10 +/- 2 torr to 1 +/- 1 torr (p less than 0.001). We conclude that LA-lv-A results in complete LV decompression. LA-lv-A should be considered as an alternative method for temporary left heart bypass.

Animals↗
PubMed1982

Photoinduced calcium release from rhodopsin-phospholipid membrane vesicles.

Brief blue-green light exposure of rhodopsin-phospholipid membrane vesicles that contained divalent cations released the cations from the vesicles. The photoinduced release is due to an increase in permeability of the membrane. The quantity of ions released depends on the initial ionic concentration inside the vesicles. At 37 degrees C and an internal concentration of 30 mM Ca2+, the initial flux for rhodopsin-egg phosphatidylcholine membrane vesicles was 0.25 +/- 0.11 Ca2+ per bleached rhodopsin per s. Similar fluxes were observed for the release of Co2+, Mn2+, Ni2+, and Mg2+. The addition of proton uncouplers and lipophilic anions accelerated the rate to approximately Ca2+ per bleached rhodopsin per s. The flux was independent of the concentration of rhodopsin in the membranes and sensitive to the head-group composition of the rhodopsin-phospholipid vesicles. Analysis of the fraction of Ca2+ released and the fraction of bleached rhodopsin per vesicle showed that a single bleached rhodopsin per vesicle is necessary and sufficient for Ca2+ release. Ca2+ release was not observed from thermally bleached rhodopsin. These results are discussed with regard to the possible role of Ca2+ as an excitatory transmitter in vision.

Animals↗
PubMed1978

Cholecystectomy during pregnancy.

While cholecystitis has definitely been associated with pregnancy, performance of cholecystectomy during pregnancy seem to be a rare occurrence. To document this observation we reviewed the records of all cholecystectomies performed during a 10-year period on women between the ages of 16 and 45 in a university hospital and a busy community hospital. Six of the 749 cholecystectomies performed at the university hospital occurred during pregnancies of from four to 26 weeks' gestation. Four of the patients were operated on emergently after an average of one week of conservation management. In no instance did the operation induce premature labor or abortion. Operative cholangiography was performed in four of the patients without detriment to the fetus. This review indicates that the need to perform cholecystectomy during pregnancy is rare, but that it can be performed with minimal risk to the fetus regardless of gestation.

Acute Disease↗
PubMed1977

Photochemical functionality of rhodopsin-phospholipid recombinant membranes.

Purified rhodopsin was incorporated into phospholipid bilayers to give recombinant membranes. The photochemical functionality in these systems was examined by low-temperature spectroscopy and by kinetic spectrophotometry. Changes in the absorption spectra of glycerol-water mixtures of rhodopsin-egg phosphatidylcholine and rhodopsin-asolectin recombinants were monitored after the sample was cooled to -196 degrees C, presented with light of wavelength greater than 440 nm, and then warmed gradually to room temperature. Absorption characteristics indicative of the spectral intermediates prelumirhodopsin, lumirhodopsin, metarhodopsin I, and metarhodopsin II were observed. The kinetics of the metarhodopsin I -o metarhodopsin II transition in these recombinants was studied by flash photolytic observation of the decay of meta I and the formation of meta II. Recombinants prepared from unsaturated phospholipids, e.g., asolectin, egg phosphatidylcholine, egg phosphatidylethanolamine, and dioleoylphosphatidylcholine, showed first-order kinetics for the transition with rates comparable to that of rod outer segment membranes. Recombinants prepared from saturated phosphatidylcholines have a retarded rate of conversion from meta I to meta II and are considered to be nonfunctional. The photochemical functionality of rhodopsin-phospholipid recombinants is dependent upon the presence of phospholipid unsaturation and the fluidity of the phospholipid hydrocarbon chains, and is independent of the polar head group of the phospholipid.

Animals↗