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PubMed1979

Extended-wear contact lenses and intraocular lenses for aphakic correction.

We evaluated extended-wear soft contact lens use in 128 aphakic eyes of 113 patients, 44 of whom had been unable to wear conventional contact lenses; 116 eyes (91%) have been successfully fitted and have worn the extended-wear lenses without significant complication. Eleven patients were unable to wear the lens or had to be discontinued for transient lens-related problems. In 103 eyes successfully fitted the lens is removed for cleaning less often than monthly. Ninety six of the 116 eyes fitted have visual acuity as good as, or better than, with aphakic correcting spectacles. The results obtained with the extended-wear soft contact lens are similar to those obtained with intraocular lenses, except for the recent high incidence of inflammation seen after intraocular lens insertion when using ethylene-oxide-sterilized lenses.

Adolescent↗

PubMed1986

Measurement of precursors for alpha-amidated hormones by radioimmunoassay of glycine-extended peptides after trypsin-carboxypeptidase B cleavage.

Using fragment 5-17 of human gastrin-17 extended with glycine at the C-terminus as hapten, three of six rabbits produced high-titer, high-avidity antisera specific for glycine-extended gastrins. In combination with trypsin and carboxypeptidase B cleavage, radioimmunoassays based on these antisera measured progastrins in some extra-antral tissues and certain malignant tumors. The results show that sequential cleavage with trypsin and carboxypeptidase B followed by radioimmunoassay of glycine-extended peptides is a rapid and accurate procedure for measurement of biosynthetic precursors of alpha-amidated peptide hormones. Moreover, the procedure seems promising in the search for tumor markers.

Animals↗

PubMed1992

Extending CD spectra of proteins to 168 nm improves the analysis for secondary structures.

The CD spectra for 10 proteins with known secondary structure have been extended from 178 to 168 nm. Combined with the data for 6 other proteins investigated previously, this produces a basis set of 16 proteins, which can be used to analyze CD spectra for secondary structure. Extending the spectra adds another CD band to the data and increases the information content from the equivalent of five to six. Analyzing the CD for each of the 16 proteins in the basis set with the 15 other proteins shows a modest improvement in the prediction of secondary structure with the extended CD spectra.

Circular Dichroism↗

PubMed1991

Extended aortic root replacement with cryopreserved allografts: do they hold up?

The extended aortic root replacement technique is used for the surgical repair of left ventricular outflow tract obstruction complicated by concurrent hypoplastic aortic annulus, multiple levels of obstruction, or aortic insufficiency. Extended aortic root replacement incorporates the concepts of aortic root replacement and aortoventriculoplasty to create a comparatively simple procedure. Unique features of the technique include the implantation of an allograft, which makes the need for anticoagulation obsolete, and use of the donor mitral leaflet to enlarge the outflow tract. Since 1985, 32 patients in Denver have undergone placement of a cryopreserved aortic valve allograft as part of extended aortic root replacement. There were four hospital deaths (13%), and 1 child underwent cardiac transplantation 30 hours after operation. In 6 months to 4.8 years of follow-up, a 14-year-old boy with familial hyperlipidemia required coronary artery bypass grafting, and 3 children experienced allograft calcification with progressive insufficiency, which prompted allograft replacement. The other 23 patients are clinically well.

Adolescent↗

PubMed1995

Extended transseptal versus conventional left atriotomy: early postoperative study.

BACKGROUND: Mitral valve operations require excellent exposure. The description of an extended vertical transseptal atriotomy by Guiraudon and associates promises to provide optimal exposure of the mitral valve. A prospective study was carried out to evaluate the merits of the extended vertical transseptal atriotomy in comparison with the conventional left atriotomy for mitral valve operations. METHODS: Conventional atriotomy was performed in 24 patients (group I) whereas 65 patients underwent the extended vertical transseptal offroach (group II). They were similar in age, sex, cause of disease, New York Heart Association functional class, left atrial size, and left ventricular function. The early postoperative rhythm changes in these two groups were compared. Statistical studies to analyze the significance of incidence of junctional arrhythmia in these two groups were carried out. RESULTS: Of the 24 patients in group I, 3 had development of transient junctional rhythm after operation, lasting less than 24 hours. None had this arrhythmia at the time of discharge. Of the 65 patients in group II, junctional rhythm was documented in 25, with a rate of occurrence of 38% (95% confidence interval, 27.6% to 52.2%). At the 6-week follow-up, 3 patients still had this junctional rhythm, with a failure to recover rate of 12% (3 of 25). CONCLUSIONS: The surgical exposure was considered excellent and closure of the atriotomy was thought to be easy in group II. However, this should be balanced against a significant (38%) incidence of transient junctional rhythm in the early postoperative period in group II, probably from injury to sinus node artery or atrial conduction pathways.

Adolescent↗

PubMed1996

Infections during extended circulatory support: University of Alabama at Birmingham experience 1989 to 1994.

BACKGROUND: The University of Alabama at Birmingham experience with investigational ventricular assist devices (VADs) used as a bridge to transplantation has increased over the past several years; it now includes 27 VAD implantations with 13 VAD runs lasting for extended periods (ie, > 30 days). A review of complications experienced by patients during extended VAD runs is warranted before the further development and testing of chronically implanted mechanical circulatory support devices. METHODS: This study focuses on the infectious complications of extended VAD support; it includes 13 patients who were supported by either a Thoratec or HeartMate VAD for longer than 30 days pending cardiac transplantation. Infection was defined as any positive culture. The infections were classed according to site and severity as follows: class I were patient-related non-blood-borne infections, class II were blood-borne infections, class III were VAD percutaneous site infections, and class IV were infections of the blood-contacting surfaces or intracorporeal components of the VAD. RESULTS: The 8 Thoratec and 5 HeartMate patients were supported for a total of 1,648 days with a range of 33 to 279 days per patient. Every patient had at least one infection; however, there were 6 patients who had no class II or IV infections during the period of support. One of these 6 patients died of a stroke, whereas the other 5 patients survived VAD support. No trends were identified for a change in the incidence of bacterial compared with fungal infections during the course of VAD support. There was no trend for a greater number of infections in patients who died during VAD support compared with those who survived. Neither class II nor IV infections precluded transplantation. Three patients died during VAD support; 1 died as a direct consequence of fungal infection. Eight patients received transplants. One patient had an unanticipated recovery of cardiac function and the VAD was removed. Support in 1 patient is ongoing. CONCLUSIONS: Infection during VAD support pending cardiac transplantation is an important cause of morbidity and mortality in patients maintained for longer than 30 days by circulatory assist. Infectious complications will probably be a prominent component of the risk associated with the use of chronically implanted mechanical circulatory assist devices and will likely have an important effect on the quality of life experienced by these patients.

Bacterial Infections↗

PubMed1990

The enzymatic and chemical reduction of extended biliverdins.

The substrate specificity of rat liver biliverdin reductase was probed using helical and extended biliverdins. The former were the ZZZ-all-syn biliverdins IX alpha and IX gamma, and the latter were the 5Z-syn, 10Z-syn, 15Z-anti; 5Z-anti, 10E-anti, 15E-anti biliverdins. It was found that the reduction rates of the biliverdins increased with the progressive stretching of their conformations. The most extended biliverdin was reduced at a higher rate than biliverdin IX alpha. The chemical reduction rates to bilirubins followed a similar pattern. Nucleophilic addition of 2-mercaptoethanol to the C10 methine was also favored in the extended biliverdins.

Animals↗

PubMed1989

Extended relational operators for statistical data manipulations in medical databases.

Conventional relational database management systems fail to address three features of statistical data management in a biomedical/clinical database, namely, that (1) statistical and medical data (SMD) require a great deal of space and need to be stored in a reduced form with minimal duplication; indeed, SMD have many derived/calculated and summary statistics that make the number of attributes in a relation (i.e., a set of records) grow rapidly and dynamically; (2) most SMD have hierarchical structures that are difficult to manage using the relational data model since SMD are stored in separate relations for duplication and space considerations; and (3) the management of SMD is made easier if it is possible to reorganize relations or group data, a capability lacking in conventional relational database management systems. In this paper, we (1) introduce five extended relational operators, (lattice) NEST, (lattice) UNNEST, MERGE, SPREAD, and GEN, to reorganize relations; (2) integrate the extended operators with conventional relational algebra and introduce the concept of the lattice relational model; and (3) give applications of the extended relational operators and the lattice relational model in solving the problems of statistical data manipulation in medical databases.

Database Management Systems↗

PubMed1994

Biological activities of two endogenously occurring N-terminally extended forms of galanin in the rat spinal cord.

The occurrence of two N-terminally extended forms of galanin in the porcine adrenal medulla was reported earlier by Bersani et al. (1991). We have synthesized and examined the ability of these two extended forms of galanin, galanin-(-7-29) and galanin-(-9-29), to bind to galanin receptors in the rat dorsal spinal cord. The effect of intrathecal (i.t.) injection of these peptides on spinal flexor reflex excitability in decerebrate, spinalized, unanesthetized rats was also studied. Both galanin-(-7-29) and galanin-(-9-29) fully displaced specific 125I-monoido-[Tyr26]porcine galanin (125I-galanin) binding to membranes prepared from rat dorsal spinal cord, with IC50 values 0.13 and 0.14 microM, respectively. The metabolic half-lives in spinal cord membranes for galanin-(1-29), galanin-(-7-29) and galanin-(-9-29) were 117 +/- 17, 271 +/- 23 and 185 +/- 19 min, respectively. I.t. injection of galanin-(-7-29) and galanin-(-9-29) mimicked the biphasic facilitatory and inhibitory effect of i.t. galanin-(1-29) on flexor reflex excitability and antagonized C-fiber conditioning stimulus-induced spinal cord hyperexcitability, but with reduced potencies compared to galanin-(1-29). We suggest that the N-terminally extended forms of galanin act as endogenous ligands with low agonist activity.

Action Potentials↗

PubMed1995

GABAA receptor antagonism in the extended amygdala decreases ethanol self-administration in rats.

The present experiments examined the role of the extended amygdala GABAA receptors in the regulation of ethanol consumption in rats. The areas of the extended amygdala studied included the central nucleus of the amygdala, the bed nucleus of the stria terminalis, and the shell of the nucleus accumbens. The effects of bilateral microinjections of a competitive GABAA receptor antagonist, 2-(3-carboxypropyl)-3-amino-6-(4-methoxyphenyl)pyridazinium bromide (SR 95531), on ethanol consumption were assessed in Wistar rats that were trained to respond for oral ethanol (10% w/v) in a two-lever, free-choice operant task during 30-min sessions using a saccharin fading procedure. Injections of SR 95531 into the central amygdaloid nucleus decreased ethanol responding significantly at doses of 2 and 4 ng without affecting water responding. SR 95531 injections into the bed nucleus of the stria terminalis reduced ethanol responding significantly at the 8 ng and 16 ng dose, while only the 16 ng dose produced a significant effect in the shell of the nucleus accumbens. Cumulative response patterns showed that intra-amygdaloid injections did not disrupt the initiation of responding. Injections into the bed nucleus of the stria terminalis and the nucleus accumbens, however, suppressed both ethanol and water responding at the highest SR 95531 doses during the first minutes. These findings suggest that GABAA receptors in the extended amygdala may be involved in the mediation of some aspects of ethanol reward.

Amygdala↗

PubMed1988

Importance of folded monomer and extended antiparallel dimer structures as enkephalin active conformation. Molecular dynamics simulations of [Met5]enkephalin in water.

Simulations of the molecular dynamics of the [Met5]enkephalin monomer and dimer structures in water have been carried out. The dynamic trajectories have been analyzed in terms of the distances between intra- or intermolecular polar atoms. The time-correlated conformational transitions of an extended monomer structure have been converged into a stationary state among the beta-bend folded forms. However, the dynamics simulation of an extended antiparallel dimer structure has shown no noticeable conformation change. These results imply that both the beta-bend monomer and the extended dimer structures exist together as the fundamental conformation of enkephalins.

Calorimetry↗

PubMed1990

TRH-extended peptides in the olfactory lobe are formed by incomplete cleavage at pairs of arginine residues in the TRH prohormone.

High concentrations of thyrotrophin-releasing hormone (TRH) are known to be present in the olfactory lobe, and the processing of the TRH prohormone in this region of the brain has been examined in this study. TRH-extended peptides have been detected in the rat olfactory lobe: these peptides accounted for approximately 11% of the total TRH immunoreactivity present in the tissue and contained the sequence pGlu-His-Pro-Gly-Arg exclusively at their N-termini. Extended peptides containing pGlu-His-Pro-Gly-Lys at their N-termini were not detected suggesting that incomplete cleavage occurs only at Arg-Arg residues in the TRH-prohormone. In view of the highly specific processing of the prohormone, it is likely that the TRH-extended peptides play important physiological roles.

Amino Acid Sequence↗

PubMed1989

Glycine-extended processing intermediates of gastrin and cholecystokinin in human plasma.

The biosynthesis of biologically active gastrin and cholecystokinin (CCK) requires the formation of carboxyl-terminally amidated peptides from glycine-extended precursors of gastrin and CCK. In previous studies we and others have identified and characterized glycine-extended forms of gastrin (Ggly) and CCK (CCK-gly) in the human gastrointestinal tract. To explore the potential biologic importance of these peptides in humans, we examined their release into the circulation. Ingestion of a standard meal induced a biphasic rise in plasma G/CCK-gly concentration, but only the initial increase correlated with gastrin release. Intraduodenal lipid infusion caused a selective rise in CCK-gly immunoreactivity with no increase in gastrin or G-gly. Gel filtration chromatography revealed that the predominant molecular form of G/CCK-gly in basal plasma coeluted with CCK8-gly, but in response to meal stimulation, increases in other molecular forms were noted. Measurement of glycine-extended intermediates of progastrin and procholecystokinin posttranslational processing in plasma may aid in determining their physiologic importance in health and disease.

Adult↗

PubMed1990

Superiority of substrate enhancement over oxygen free-radical scavengers during extended periods of cold storage for cardiac transplantation.

When cold storage techniques used in cardiac transplantation are extended beyond 3 hours, there is significant depression in ventricular function. This study was undertaken to determine whether the addition of the amino acid L-glutamate or the oxygen free-radical scavengers superoxide dismutase (SOD) and catalase (CAT) during extended periods of cold storage would improve ventricular function. Fifteen rabbit hearts were placed on a Langendorff apparatus, arrested with crystalloid potassium cardioplegia, stored in iced saline solution (3 degrees C) for 5 hours, and then reperfused at 37 degrees C for 1 hour. In five hearts L-glutamate (4 mmol/L) was added to the cardioplegic and reperfusate solutions, and five hearts received SOD (1500 units/kg/L) and CAT (3500 units/kg/L), whereas in five others the cardioplegic and reperfusate solutions were unmodified. Hearts treated with L-glutamate had the best recovery of positive dP/dt (79%* glutamate vs 49%* SOD and CAT vs 36% unmodified), negative dP/dt (76%* glutamate vs 53% SOD and CAT vs 45% unmodified), developed pressure (67%* glutamate vs 51% SOD and CAT vs 45% unmodified), and coronary flow (81%* glutamate vs 79%* SOD and CAT vs 62% unmodified). We conclude that substrate enhancement with L-glutamate provides superior myocardial protection than is possible with the oxygen free-radical scavengers SOD and CAT during extended periods of cold storage for cardiac transplantation.

Animals↗

PubMed1990

Microleakage of extended and nonextended Class I composite resin and sealant restorations.

Favorable results of composite resin sealant restorations in narrow occlusal cavities raise the question of whether extended cavity preparation is justified. Larger restorations are subject to increased polymerization shrinkage. Microleakage of extended and nonextended composite resin sealant restorations was tested in this study. Forty extracted caries-free third molars were allocated to four experimental groups. Occlusal cavity preparations were prepared, varying from narrow cavities restricted to the central fossa to preparations eradicating all fissures. Composite resin restorations were inserted with or without a base and with or without a sealant. Control restorations were inserted in nonetched preparations. Microleakage occurred when cavities were not etched and occassionally when a sealant was not applied. Conclusions indicate that a class I composite resin restoration extended beyond the central fossa can be free of microleakage if covered with a fissure sealant.

Acid Etching, Dental↗

PubMed1995

A prospective study of bone density and pregnancy after an extended period of lactation with bone loss.

OBJECTIVES: To determine if pregnancy after an extended period of lactation curtails the recovery of maternal bone mineral density. METHODS: Twenty-five women who fully breast-fed their infants for at least 6 months and had a subsequent pregnancy within 18 months of initiating lactation were studied longitudinally. Twenty controls breast-fed similarly, but had no subsequent pregnancy. The women were healthy, well-nourished, and between 20-40 years old. Bone mineral density was measured by dual x-ray energy absorptiometry at the spine and hip. RESULTS: Both cases and controls lost bone mineral density with extended lactation. The case group had a bone mineral density recovery comparable to the controls. CONCLUSION: Women with the dual calcium demands of extended lactation and a subsequent pregnancy are not at risk for failure of bone recovery to pre-lactation levels.

Absorptiometry, Photon↗

PubMed1994

Postchemotherapeutic surgery for metastatic testicular germ cell tumors: results of extended primary chemotherapy and limited surgery.

OBJECTIVE: Postchemotherapy surgery has become an increasingly important treatment for residual masses in germ cell tumors of the testis. However, it is still a challenge to find the optimal combination of chemotherapy and surgery for better survival and cure rates with lowest morbidity. This study evaluated the effectiveness of extended chemotherapy followed by surgery resecting only the residual masses. METHODS: After an extended course (one or two additional courses after there is no decrease in tumor size and/or after the normalization of tumor markers) of combination chemotherapies with cisplatin-based regimens, 32 patients underwent surgery for metastatic germ cell tumors of the testis. Complete excision of radiologically determined residual masses and macroscopically suspicious neighboring nodes was performed rather than a conventional retroperitoneal lymph node dissection. RESULTS: Histopathologic examination of the resected specimens revealed teratoma in 17 (55%), fibrosis and/or necrosis in 9 (26.5%), and active residual tumor in 8 (23.5%) of the patients. The patients with residual tumor have been treated with additional chemotherapy. In the follow-up (mean, 28.5 months) 4 patients have relapsed, and 1 died. None of the patients with residual teratomas have shown relapse. Only 1 of the 32 patients has had retrograde ejaculation. CONCLUSIONS: A more conservative approach, such as excision of the residual masses after an extended course of chemotherapy, has given excellent results both in the outcome of the patients in the follow-up and in the rate of retrograde ejaculation. We therefore suggest that this approach would be a good alternative to nerve-sparing surgery following chemotherapy.

Adult↗

PubMed1986

Postoperative extended-field irradiation in patients with pelvic and/or common iliac node metastases from cervical carcinoma stages IB to IIB.

Radical hysterectomy with pelvic and common iliac lymphadenectomy was done for 207 Stage IB (148), IIA (19), and IIB (40) cervical carcinomas. Pelvic nodal involvement was limited in 30 (14.5%) cases, whereas common iliac nodes were involved in 16 (7.7%) cases. Common iliac node metastases were significantly increased, when the number of positive pelvic nodes increased from 2 to 3 or 4 or more (21.4% to 73.3%, P less than 0.05), when the tumor invaded deeper than 20 mm (3.7% to 22.2%, P less than 0.001), and when the tumor extended into parametrial tissues (4.8% to 14.8%, P less than 0.05). Postoperative extended-field irradiation was administered to 40 patients with nodal metastases. The 3-year disease-free rates were 85% in 24 patients with positive pelvic nodes, and 51% in 16 patients with common iliac node metastases; 70% in total. These results indicate that postoperative extended-field irradiation is essential for those patients with nodal metastases from locally resectable cervical carcinomas.

Adenocarcinoma↗