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Biomedical subjects

R Schwartz

Publications and source records attributed to R Schwartz.

At least 181 records · Page 10Linked to original sources
PubMed1990

Use of a prefabricated splint for segmental augmentation of the mandibular alveolar ridge with hydroxyapatite.

Hydroxyapatite is a biocompatible material for augmentation of edentulous ridges to improve patient comfort and denture stability. The problems associated with hydroxyapatite are generally related to the amount of material introduced and the site of implantation. This article describes the use of a prefabricated splint that permits localization of the implant material to selected sites of the mandible and restricts the amount of material used. Fabrication of this splint under the guidance of the prosthodontist and oral surgeon permits the most effective use of this technique.

Acrylic Resins↗
PubMed1990

Effect of a ZOE temporary cement on the bond strength of a resin luting cement.

This study was conducted to determine if a eugenol-based temporary cement affected the bond strength of a dual-cure cement to etched enamel. Dicor buttons were cemented to etched enamel surfaces after pretreatment with a non-eugenol containing cement, a eugenol containing cement and a control. This study concluded that shear bond strengths were unaffected by the temporary cement, provided the enamel surface was cleaned with pumice and etched with 37% phosphoric acid.

Acid Etching, Dental↗
PubMed1990

3-Hydroxy-3-methylglutaryl-CoA lyase deficiency as detected by radiochemical assay in cell extracts by thin-layer chromatography, and identification of three new cases.

In this rapid radiochemical assay for 3-hydroxy-3-methylglutaryl-coenzyme A lyase (I) activity in cell extracts, DL-3[glutaryl-3-14C]hydroxy-3-methylglutaryl-coenzyme A is used as substrate and the radiochemical product, [3-14C]acetoacetic acid, is converted to the more stable [3-14C]-3-hydroxybutyric acid in the presence of added NADH and 3-hydroxybutyrate dehydrogenase. Substrate and product are separated and quantified by thin-layer chromatography on cellulose (solvent system: butanol/water/formic acid, 77:13:10 by vol). All reagents for the assay are commercially available. No detailed column chromatography or spectrophotometry is required. Thus the assay is suited for any clinical laboratory. Using this procedure, we studied cultured fibroblasts or lymphocytes isolated from whole blood from five patients in whom the urinary organic acid profile was suggestive of deficiency of I. Three patients had less than or equal to 18% of control I activity in fibroblast or lymphocyte extracts. The other two had activity within the normal range. In one of the latter cases, urinary excretion of three of the characteristic acids disappeared with age, and 3-hydroxyisovaleric acid excretion was within normal limits. The other case presented with urinary excretion of moderate amounts of all four metabolites and the characteristic absence of urinary ketone bodies. Evidently, confirmatory enzyme studies should be undertaken, even when the profile of urinary organic acids appears definitive for this deficiency.

Cells, Cultured↗
PubMed1990

[Clinical value of new tonometers].

In a clinical study four different tonometers [a hand-held applanation tonometer (HAT), a tonometer that works according to the principle of Mackay-Marg and two noncontact tonometers (NCT A und NCT B)] were compared with respect to accuracy and precision. In a randomized sequence, two physicians took six measurements of both eyes of 99 patients using the four different instruments. The interval between the two measurements in one eye was 3 min. The correlations of repetitive measurements for one tonometer in one eye showed good results for HAT (r = 0.985, SD = 1.66 mmHg), but significantly worse values for the other three tonometers (Mackay-Marg type: r = 0.85, SD = 3.5 mmHg; NCT A and NCT B: r = 0.91, SD = 2.93 mmHg). To establish the accuracy, the pressure values of the Mackay-Marg type and NCT A and NCT B were compared with those of the well-established HAT. The results were as follows: Mackay-Marg type: r = 0.84, SD = 3.78 mmHg; NCT A: r = 0.86, SD = 4.55 mmHg; NCT B: r = 0.89, SD = 3.26 mmHg). We conclude that the three tonometers tested (one based on the Mackay-Marg principle and the other two on the non-contact principle) are not suitable for clinical and scientific use.

Adolescent↗
PubMed1989

Amniotic fluid erythropoietin predicts fetal distress in Rh-immunized pregnancies.

Repeated amniotic fluid erythropoietin measurements in 23 Rh-immunized pregnancies were done to evaluate erythropoietin levels of amniotic fluid as an indicator of fetal distress (umbilical artery, pH 7.14 or less, or 1-minute Apgar score of 4 or less). Amniotic fluid erythropoietin levels did not vary significantly between 168 and 273 gestational days in the pregnancies without fetal distress. Increasing levels of amniotic fluid erythropoietin predicted highly reliably severe fetal distress at birth. Whether erythropoietin levels of amniotic fluid can also predict fetal distress in other pathologic pregnancies needs further study.

Amniotic Fluid↗
PubMed1989

Outcome of a unique youth drug abuse program: a follow-up study of clients of Straight, Inc.

A unique feature of the 12-hour per day Straight, Inc., program is temporary placement of the client with the family of a client who has progressed further in the program. Eighty-five (85) percent of the clients reported that their drug use was less at follow-up than when they started in the program. Follow-up reports by parents indicated their impression of a statistically significant decrease in the proportion of clients who were still involved in substance use. Statistically significant improvement at follow-up was also reported by the clients on seven of eight other selected outcome criteria (e.g., suicidal thoughts, physical violence, number of arrests, etc.). The majority of the clients reported that they were "satisfied" with the program (70%), that the program "helped" them (74%), and, specifically, that the program helped them with their relationship with their parents (69%).

Adolescent↗
PubMed1989

AIDS-related angiomatosis.

We report multifocal cutaneous and mucosal vascular proliferations with the clinical and histological features of lobular capillary hemangioma and histiocytoid hemangioma in a 32-year-old acquired immunodeficiency syndrome patient. The lesions resolved subsequent to erythromycin therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1989

In vitro distribution of diacetyl didemnin B in human blood cells and plasma.

We have utilized [3H]diacetyl-didemnin B ([3H]DB) in a series of in vitro experiments to determine the time course of equilibration of [3H]DB between plasma and blood cells, the distribution of [3H]DB among blood cells, and the distribution of [3H]DB in plasma. Within 45-60 min at 37 degrees C, approximately 55% of [3H]DB added to whole blood remained in the plasma. Of the drug associated with blood cells, 77% was found with the red blood cells, 18% with the lymphocytes, and 5% with the granulocytes. However, on the basis of amount of drug uptake per cell, lymphocytes incorporated nearly 400 times more and granulocytes nearly 30 times more [3H]DB than red blood cells. No specific association of [3H]DB with a particular lymphocyte subset was detected. Additionally, it appears that [3H]DB in plasma was associated to a large extent with albumin.

Antineoplastic Agents↗
PubMed1989

Early rehabilitation in trauma centers: have speech-language pathology services progressed? A 3-year follow-up.

Trauma centers around the United States were surveyed to determine the extent and availability of early, aggressive, and appropriate speech rehabilitation services offered to trauma victims. Although significant increases were noted in specialty programs, augmentative systems usage, and follow-up services, there remains need for continued development in many aspects of early rehabilitation programs. As sophisticated medical management continues to salvage lives of America's prime resource, its young people, an added commitment is needed from all rehabilitation professionals to provide the right opportunities for neurological recovery.

Follow-Up Studies↗
PubMed1988

DNA rearrangement of a homeobox gene in myeloid leukaemic cells.

A homeobox gene rearrangement has been detected in WEHI-3B mouse myeloid leukaemic cells. The rearranged gene was identified as Hox-2.4 which is a member of the Hox-2 gene cluster on mouse chromosome 11. Both the normal and the rearranged genes were cloned and analysed, and the rearranged genomic Hox-2.4 gene was sequenced. The results indicate that the rearrangement is due to insertion of an intracisternal A particle 5' upstream to Hox-2.4 and that this resulted in constitutive expression of the homeobox gene. It is suggested that constitutive expression of the homeobox gene may interrupt the normal development program in these leukaemic cells.

Amino Acid Sequence↗
PubMed1988

Visceral myopathy of the gastrointestinal and genitourinary tracts in infants.

We describe 4 infants who had chronic intestinal pseudoobstruction caused by visceral myopathy. Three of the 4 were girls. Two were symptomatic at birth and 2 were symptomatic by 3 wk of age. All had abdominal distention and emaciation, 3 of the 4 had severe obstipation and fecal impactions, and 3 had signs of urologic obstruction. All had gaseous distention of the small bowel and colon, and barium studies showed dilated small bowel and colon, with slow transport through the small intestine. Two of 3 had enlarged stomachs and slowed gastric emptying, and 3 had dilated bladders and ureters. The 1 infant studied by esophageal manometry had absence of esophageal contractions. Despite total parenteral nutrition in 3, all died within 10-18 mo. The pathologic features of visceral myopathy were identified in variable sample sites from the esophagus, stomach, small intestine, colon, bladder, and ureter of the 4 infants. Of 170 family members related to 3 of the infants, there was no consanguinity and no one appeared to be clinically affected. Thus, an infantile form of visceral myopathy exists which, pathologically, is identical to the familial and sporadic forms of visceral myopathy previously identified in adolescents and adults.

Digestive System↗