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Biomedical subjects

R Schultz

Publications and source records attributed to R Schultz.

At least 73 records · Page 4Linked to original sources
PubMed1990

Ten-year results with the St. Jude Medical prosthesis.

Although the hemodynamic characteristics and durability of the St. Jude valve prosthesis have been reported, the need for and the degree of anticoagulation in patients who receive these valves remain uncertain. Our 10-year experience with 165 patients (100 men and 65 women, mean age of 58 +/- 13 years), who underwent valve replacement with St. Jude prostheses, is reported. Of the 165 patients, 147 were treated with warfarin. A prothrombin time 1.3 to 1.8 times control (range 15 to 20 seconds) was maintained in 134 patients with single valve and 1.8 to 2 times control (range 20 to 25 seconds) in 13 patients with double valve prostheses. The 10-year actuarial event-free incidence from thromboembolic and hemorrhagic complications was 84 and 95%, respectively. Of the 8 patients receiving antiplatelet therapy alone, 4 had thromboembolic events. Of the 10 patients on neither warfarin nor antiplatelet therapy, 3 had thromboembolic events. The 10-year actuarial event-free incidence from valve failure was 95%. The 10-year actuarial patient survival was 55%. Thus, the St. Jude valve is a safe and reliable prosthesis with acceptable overall long-term performance in patients given a modest anticoagulation regimen. Patients who receive St. Jude prosthetic valves without anticoagulants have a high incidence of thromboembolic events despite therapy with antiplatelet agents.

Adolescent↗
PubMed1990

A de novo X;3 translocation in Rett syndrome.

Rett syndrome is a neurodegenerative disorder that occurs exclusively in females. The syndrome is sporadic in most cases with the exception of a few familial cases with an inheritance pattern through maternal lines. These observations raised the possibility that Rett syndrome may be due to an X-linked dominant mutation which is lethal in the male. To evaluate this hypothesis, we have systematically performed high-resolution chromosome analysis on 28 patients with Rett syndrome searching for deletions and/or translocations. In one patient, a de novo balanced translocation was observed with the chromosome constitution of 46,X,t(X;3) (p22.11;q13.31). This finding supports the hypothesis of an X-linked dominant mutation and suggests that the Rett gene might map to distal Xp21 or proximal Xp22.

Child, Preschool↗
PubMed1990

Extrapyramidal involvement in Rett's syndrome.

Extrapyramidal dysfunction is poorly characterized in Rett's syndrome, a neurodegenerative disorder in girls. We studied the motor and behavioral findings in 32 Rett's syndrome patients, 21 months to 30 years old. In addition to the typical stereotyped movements and scoliosis, other motor disturbances included bruxism, sialorrhea, ocular deviations, parkinsonian findings, dystonia, myoclonus, and athetosis. The types of movement disorders seemed to be age-related, with the hyperkinetic disorders occurring in the younger patients and the bradykinetic disorders occurring more frequently in the older patients.

Adolescent↗
PubMed1990

[Viruses relevant to the mother-child relationship].

Virus that may infect the mother with serous consequences for the child include rubella, cytomegalovirus, herpes simplex, hepatitis B, papilloma and AIDS. They may be transmitted from mother to child before, during or after delivery. Preventive measures include: a) vaccination of females against rubella; b) vaccination and administration of gammaglobulin anti-hepatitis B in newborns from infected mothers and c) cesarean section in pregnant women with genital infection by herpes or papilloma. Early treatment with anti-viral agents may help reduce the intensity of viral infections in the newborn. Thus, several measures must be considered in the prevention and treatment of fetal or neonatal viral infections.

Adult↗
PubMed1989

[Maternal genital herpes: virus isolation during the third trimester of pregnancy and at delivery].

We followed 42 pregnant women at high risk for genital herpes infection. Viral isolation was attempted weekly from the 34th week of pregnancy. One or more episodes of herpes infection developed in 74% of women. The virus was isolated in 28% after 34 weeks and in 22% after 37 weeks. A prophylactic cesarean section was performed in the latter group; only one of these women had a positive viral isolation at delivery. The HSV-2 of virus was found in 83% of cases and HSV-1 in 17%.

Adult↗
PubMed1988

Developmental expression of PDGF, TGF-alpha, and TGF-beta genes in preimplantation mouse embryos.

Control of growth and differentiation during mammalian embryogenesis may be regulated by growth factors from embryonic or maternal sources. With the use of single-cell messenger RNA phenotyping, the simultaneous expression of growth factor transcripts in single or small numbers of preimplantation mouse embryos was examined. Transcripts for platelet-derived growth factor A chain (PDGF-A), transforming growth factor (TGF)-alpha, and TGF-beta 1, but not for four other growth factors, were found in whole blastocysts. TGF-alpha, TGF-beta 1, and PDGF antigens were detected in blastocysts by immunocytochemistry. Both PDGF-A and TGF-alpha were detected as maternal transcripts in the unfertilized ovulated oocyte, and again in blastocysts. TGF-beta 1 transcripts appeared only after fertilization. The expression of a subset of growth factors in mouse blastocysts suggests a role for these factors in the growth and differentiation of early mammalian embryos.

Animals↗
PubMed1988

Mechanosensory interneurons (MSIs) in the crayfish 6th abdominal ganglion are inhibited by activation of other MSIs.

1. Identified mechanosensory interneurons (MSIs) in the 6th abdominal ganglion of the crayfish Procambarus clarkii have been shown to inhibit other projecting MSIs. 2. Interneurons sensitive to water-current stimulation of the tailfan, and which inhibited the tactile response of other MSIs when activated by depolarizing currents, were identified by iontophoresis of fluorescent dye. 3. Ten inhibitory interneurons have been identified, including both non-adapting, directional cells and phasic "touch" cells. 4. Inhibition triggered by activation of the identified cells was not widespread among fibers in the connectives. 5. Inhibition recorded intracellularly was mediated by compound inhibitory postsynaptic potentials of long duration (300-400 msec) and latencies of 13-15 msec, and therefore was apparently polysynaptic. 6. Depolarization and/or activity in MSIs, which modulates the stimulus response characteristics of related cells is a possible mechanism for contrast enhancement among directional or frequency-selective interneurons.

Abdomen↗
PubMed1988

Morphohistometric investigations of placentas of diabetic patients in correlation to the metabolic adjustment of the disease.

In order to determination if an interdependence exists between the well-known maturational disturbances in placentas of diabetics and the quality of metabolic adjustment, a morphometric study covering 7,500 terminal villi of 50 placentas was performed. The diabetic mothers were divided into two groups according to satisfactory or unsatisfactory blood glucose values. Significant differences in placental retardation were observed between both diabetic groups and a normal control group. Although outcomes did not differ greatly between the two diabetic groups, macrosomia and the ratio of malformations in the newborns correlate with unsatisfactory metabolic management. Small-for-date babies, the need for early termination of pregnancy as well as pre-eclampsia are related to the severity and duration of the disease.

Blood Glucose↗
PubMed1987

Magnetic resonance imaging of gadolinium-labeled monoclonal antibody polymers directed at human T lymphocytes implanted in canine brain.

Two different murine monoclonal anti-human T cell antibodies, that were coupled to gadolinium (Gd), bind specifically to human T lymphocyte cells implanted in canine brain. This binding was at a concentration of Gd sufficient to detect the implanted cells and to distinguish them from the surrounding brain tissue with magnetic resonance imaging (MRI) at a field strength of 1.5 Tesla. These Gd-labeled immunoglobulin preparations did not bind bovine T cells at a concentration sufficient to be detected on MRI. A protein solution containing the immunoglobulins (100 micrograms), gelatin (2 mg), and bovine serum albumin (2.5 mg) was reacted with the dianhydride of diethylenetriaminepentaacetic acid (DTPA); the DTPA serves as a metal chelator and as a protein crosslinking agent. The DTPA-protein complex was reacted with Gd chloride. There were approximately 10 DTPA residues per protein molecule in the modified protein mixture. Isolated human or bovine monocytes (approximately 12 million cells) were implanted in the brains of anesthetized dogs in a volume of 40 microliters. The blood-brain barrier was then disrupted by the intra-arterial injection of hyperosmotic mannitol, and the Gd-labeled antibodies were injected through a catheter placed at the branch of the internal and external carotid arteries. The brains were imaged 48 to 72 hours later. The MRI scans revealed a markedly decreased T1 relaxation time with a high signal intensity (TE = 25 msec, TR = 200 msec) related to the human T cell implants. There was no evidence of decreased T1 at the site of the bovine T cells. Neither control murine gamma globulin coupled to Gd-DTPA nor anti-human T cell antibodies uncoupled to Gd modified the MRI contrast of the human T cells in the brain.

Animals↗