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Biomedical subjects

J Miller

Publications and source records attributed to J Miller.

At least 721 records · Page 40Linked to original sources
PubMed1990

[Subendocardial resection in the surgical treatment of ventricular arrhythmia in patients with ischemic heart disease].

The authors have much experience in diagnosing and managing ventricular arrhythmias in patients with coronary heart disease. In most cases, the arrhythmogenic areas are present in the subendocardium and surgeries aimed at improving myocardial revascularization prove to be frequently ineffective in managing arrhythmias. Subendocardial resection proposed by the authors was used in 284 patients. Mortality rates were in 15%, the deaths were mainly due to phenomena of heart failure. Positive results were achieved in 160 (67%) patients. To evaluate the efficacy of the surgical management, the authors consider it advisable to apply programmed endocardial stimulation. The value of pre- and intraoperative mapping is the most important factor that determines the outcome of the surgical management. Subendocardial resection should be regarded as the method of choice just at early stages of the disease in patients with recurrent ventricular tachycardias occurring after acute myocardial infarction.

Aged↗
PubMed1990

The fragmentation of 670A MeV neon-20 as a function of depth in water. II. One-generation transport theory.

The results of an experiment to study the interaction of a beam of 670A MeV neon ions incident on a water column set to different thicknesses were compared with a "first principles" transport calculation in the straight-ahead approximation. This calculation assumes that the nuclear interactions of the incident particles lead to a secondary particle with the velocity of the incident projectile at the interaction point moving in the direction of the incident projectile. Subsequent nuclear interactions of the fragments were taken into account partially, by calculating the nuclear attenuation of the fragments in the residual material, but were not taken into account as a source of further nuclear interaction products. Fluence spectra were calculated per unit incident neon fluence for 14 absorber thicknesses. The acceptance for each fragment was calculated based on a knowledge of the material in the beam and of the beam extraction energy. The theoretical spectra were multiplied by the calculated acceptance and convoluted with the LET resolution associated with the experiment. The stopping power used in the transport calculation was found to predict a range approximately 1.6% shorter than that given by experiment; this small difference resulted in significant discrepancies between theory and experiment in the stopping region. For particles not stopping in the absorber, the transport calculation was accurate to within 30% for depths less than approximately 15 cm; the effects of tertiary particles become significant at greater depth.

Energy Transfer↗
PubMed1990

Maternal mortality in a maternal-fetal medicine intensive care unit.

Maternal mortality in a large, tertiary-care, intensive care, referral center was reviewed for a six-year period. The first three years of the review were prior to the institution of a maternal-fetal medicine intensive care unit, located in the labor-and-delivery suite. The subsequent three years encompassed a period during which an intensive care unit staffed by maternal-fetal medicine specialists and obstetric anesthesiologists was established in the labor-and-delivery suite. The maternal mortality rate was 21.7/100,000, or 10 maternal deaths in 45,984 deliveries, prior to establishment of the unit and 22.1/100,000, or 11 maternal deaths in 49,700 deliveries, after establishment of the unit. The major causes of maternal mortality were pregnancy-induced hypertension, hemorrhage and infection. It appears that a multi-disciplinary team composed of maternal-fetal medicine specialists and obstetric anesthesiologists can provide the same level of care for critically ill obstetric patients that traditionally would be provided by medical intensive care specialists.

Adolescent↗
PubMed1990

Benign pneumatosis intestinalis with subcutaneous emphysema in a liver transplant recipient.

Pneumatosis intestinalis (PI) occurred in a pediatric liver transplant recipient experiencing chronic rejection. Signs and symptoms included abdominal distention, subcutaneous emphysema, fever, and malaise. Antibiotic treatment and nasogastric decompression resulted in prompt relief of symptoms, and surgery was not necessary. The etiology, pathophysiology, and therapy of this rare condition are discussed.

Child, Preschool↗
PubMed1990

An argument for circumcision. Prevention of balanitis in the adult.

A cross-sectional study and a retrospective study were performed to determine the frequency of balanitis in a randomly selected group of dermatology patients. A total of 398 subjects were included in the cross-sectional study, 213 (53.5%) of whom had been circumcised. Balanitis was diagnosed in 2.3% of circumcised men and in 12.5% of uncircumcised men. In patients with diabetes mellitus, balanitis occurred with a prevalence of 34.8% in the uncircumcised population, compared with 0% in the circumcised population. Balanitis did occur with increased frequency in the diabetic population (16%), regardless of circumcision status, compared with the nondiabetic population (5.8%). Of 63 circumcisions performed at our institution between 1987 and 1989, 28.6% were for the treatment of balanitis; 44.4%, for phimosis (which was probably induced by chronic balanitis); 19% in preparation for placement of penile prostheses; and 8% for miscellaneous reasons. No complications of circumcision were reported. In this group of patients, balanitis was more frequent in diabetic than in nondiabetic uncircumcised men (50% vs 15.4%).

Adult↗
PubMed1989

The role of the Ia-invariant chain complex in the posttranslational processing and transport of Ia and invariant chain glycoproteins.

The invariant chain (Ii) is a nonpolymorphic glycoprotein that associates with the Ia alpha- and beta-chains of MHC class II Ag during their transport to the cell surface. Although surface expression of Ia can occur in the absence of Ii, it has not been shown whether the intracellular association of Ia and Ii affects the biosynthetic rate or specificity of posttranslational modifications to the individual molecules. Analysis of transfected cell lines carrying either Ia, Ii, or both Ia and Ii demonstrated efficient assembly of alpha-beta whether or not Ii was present. Pulse-chase studies and two-dimensional gel electrophoresis showed that Ii did not affect the addition of Ia N-linked oligosaccharide chains, or the extent or rate of their conversion to the complex form, nor did it affect the sulfation of alpha and beta glycoproteins. Ii also did not affect the rate of Ia synthesis or appearance of Ia at the cell surface. In contrast, Ia dramatically affected the posttranslational modification of Ii. Although invariant chain was modified by addition of fatty acid, N-linked oligosaccharide, and glycosaminoglycan in the absence of Ia, the processing of Ii-linked oligosaccharide into more acidic, terminally glycosylated forms was significantly less when Ia was absent, and although conversion to proteoglycan did occur, the glycosaminoglycan chains were significantly shorter than normal. The disappearance of radiolabel from the 31,000 Da form of Ii was faster when Ia was present, and the processing of Ii was more rapid when it was associated with Ia. Thus, the rate and manner in which Ii enters and passes through the Golgi is critically affected by Ia.

Animals↗
PubMed1989

A novel method for the purification of the Xenopus transcription factor IIIA.

We have developed a quick and simple purification method that yields large quantities of the Xenopus zinc finger protein transcription factor IIIA (TFIIIA). The protein is purified in the form of the 7S storage particle (TFIIIA/5S RNA complex) found in the ovaries of immature Xenopus. Our method yields 0.5 to 1 mg of pure 7S particle per ovary. It involves a high speed centrifugation step, fractionation on a gel filtration column and a precipitation step using calcium chloride. TFIIIA purified using this protocol retains full DNA binding activity and has the expected zinc ion content.

Animals↗
PubMed1989

Structural analysis of the gene for human acidic fibroblast growth factor.

Genomic clones derived from the gene for human acidic fibroblast growth factor (aFGF) have been isolated. Nucleotide sequence analysis of these clones revealed that the coding region of the human aFGF gene is interrupted by two introns, located at precisely homologous locations to introns in four other members of the FGF gene family, strongly indicating a common evolutionary origin for these genes. Northern blot analyses of the multiple aFGF transcripts found in serum-stimulated human foreskin fibroblasts indicated that the aFGF gene also contains a third intron, lying in the 5' untranslated region.

Amino Acid Sequence↗
PubMed1989

Diminished antigen processing by endosomal acidification mutant antigen-presenting cells.

The role of acidified endosomes in Ag processing was investigated using mutant Chinese hamster ovary cells that express temperature sensitive defects in their acidification mechanism. These cells were transfected with MHC class II genes to convert them to APC. When such mutant cells were incubated at the nonpermissive temperature, losing early endosomal but not lysosomal acidification, their ability to process several native protein Ag was impaired. The nonpermissive temperature did not affect Ag processing by transfected wild type parental cells. Furthermore, T cells were stimulated normally under these conditions when the mutant cells presented antigenic peptide fragments, which do not require processing. The mutant cells were also not defective in the uptake and overall degradation of native antigen. The elimination of Ag processing by paraformaldehyde and chloroquine treatment of the Chinese hamster ovary cells indicates that these cells do not use a different process than physiologic APC. These results suggest that acidification of early endosomes is an important event in Ag processing.

Animals↗
PubMed1989

Clinical, pathological, and biochemical studies on an infantile case of sulfatide/GM1 activator protein deficiency.

A 28-month-old black male died with severe complications of mental and motor deterioration, seizures, and aspiration. Autopsy demonstrated moderate liver enlargement, normal spleen and kidneys, small testes, and a grossly normal brain. Further examination showed irregular macrogyrae with evidence of a storage or sclerotic process. Thin layer chromatography of the lipids in formalin-fixed tissue demonstrated elevated levels of ceramide trihexoside and possibly sulfatides in liver and a decrease in the ratio of galactosylceramide to sulfatide in brain. Examination of the gangliosides in formalin-fixed brain indicated a slight increase in the percentage of GM1 ganglioside and a clear elevation in GM2 and GM3 gangliosides. Cultured skin fibroblasts had a normal activity for a large number of lysosomal enzymes including arylsulfatase A and galactocerebrosidase. When the cells were loaded with [14C]sulfatide only about 12% of the sulfatide was metabolized after 3 days. Extracts of the cells were subjected to SDS-PAGE and immunoblotting with antisphingolipid activator protein-1 (SAP-1) rabbit antiserum, and no cross-reacting material was detected confirming the diagnosis of metachromatic leukodystrophy caused by SAP-1 deficiency. This patient was clinically more severe than the other patients described previously with this deficiency. Further studies are underway to define the nature of the mutation in this patient.

Autopsy↗
PubMed1989

Fatigue of acrylic bone cement--effect of frequency and environment.

This study was conducted to investigate some fundamental fatigue testing variables as they apply to the response characteristics of acrylic bone cement. Cyclic loading under load control was conducted at frequencies of 1, 2, 5, 10, and 20 Hz in air at room temperature. At a tensile stress range of 0.3-20.0 MPa the fatigue life increased linearly with logarithmic frequency. The effect of conditioning and testing in saline at both room temperature and 37 degrees C at similar stress levels and a frequency of 10 Hz were also examined. When compared to dry testing at room temperature, testing in saline at 37 degrees C resulted in a reduction in fatigue life while testing in saline at room temperature produced an increase in fatigue life. Of a number of statistical distributions considered, the Weibull was found to be the most appropriate in documenting the findings of this investigation. A companion fractographic investigation of the failure surfaces demonstrated distinct regions of crack growth and fast fracture.

Acrylates↗
PubMed1989

Treatment of movement disorders with trihexyphenidyl.

The clinical efficacy of the trihexyphenidyl was investigated in 100 patients with movement disorders. The study group consisted of 54 women and 46 men. Their ages ranged from 18 to 70 years, and their duration of illness varied from a few months to 36 years. Each patient had a videotape of the movements and a neurological examination, before administration of the drug, at the time of maximum or effective dosage, and one week after withdrawal from trihexyphenidyl. The drug was administered at an initial total daily dose of 2 mg and gradually increased to a total daily dose of 60 mg over a period of 4-6 weeks. Improvements were rated both clinically and from the videotapes. Three groups of movement disorders demonstrated a significant response to trihexyphenidyl: (1) dystonia 37%; tonic torticollis demonstrated a significantly better response than the clonic variant (80% vs. 22%). (2) rhythmic-oscillatory movements of brainstem-cerebellar origin (palatal myoclonus, pendular nystagmus, facial myokymia) 90%; (3) cerebellar tremor 75%. Among 32 responders, 17 (56%) continued taking trihexyphenidyl beyond 24 months. Side effects consisted of dryness of the mouth, jitteriness, stomatitis, blurred vision, and forgetfulness.

Adolescent↗