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Biomedical subjects

R L Berkowitz

Publications and source records attributed to R L Berkowitz.

At least 181 records · Page 10Linked to original sources
PubMed1980

Characterization of Soybean Plasma Membrane during Development: FREE STEROL COMPOSITION AND CONCANAVALIN A BINDING STUDIES.

PLASMA MEMBRANE PREPARATIONS FROM SOYBEAN ROOT AND HYPOCOTYL CONTAINED THE FOLLOWING FREE STEROLS: cholesterol, campesterol, stigmasterol, and sitosterol. The cholesterol level was relatively low in root plasma membrane (less than 0.5%) but was 1.4 to 2.4% in hypocotyl membrane. The relative levels of the three other sterols fluctuated with cellular development and tissue source. Campesterol level decreased with the development of both root and hypocotyl membrane. With development, stigmasterol increased greatly in root membrane but remained constant in hypocotyl membrane, and sitosterol, the major free sterol component of all membrane preparations, decreased in root membrane but increased slightly in hypocotyl membrane.Electron microscope studies indicated that all root plasma membrane preparations were equivalent in terms of relative purity. Hypocotyl membrane preparations contained significantly greater levels of contaminating membrane components.Root plasma membrane fractions were between 70 and 80% pure as determined by staining with the phosphotungstic acid-chromic acid procedure (PACP). Staining was most definitive for vesicles present in complete cross-section. Electron micrographs showed that vesicles treated with concanavalin A (Con A)-ferritin were extensively labeled at the outer surface indicating the presence of mannosyl and/or glucosyl residues at the vesicle surface. Densities of ferritin were highest on vesicles present in oblique section. PACP and Con A-ferritin were thus complementary with respect to topological specificity.The percentage of Con A-ferritin-labeled and/or PACP-stained vesicles in plasma membrane root preparations was greater than 80%. Con A did not bind in purified tonoplast preparations, and binding was reduced in regions of low PACP reactivity in a root membrane fraction containing a lowered proportion of plasma membrane. Con A specificity for the plasma membrane in subcellular membrane preparations is discussed.

Journal Article↗
PubMed1980

Pregnancy in a patient with cystic fibrosis and idiopathic thrombocytopenic purpura.

A pregnant patient with cystic fibrosis and idiopathic thrombocytopenic purpura (ITP) is presented. Management of the pregnancy was complicated by the coexistence of the 2 diseases and consisted of antibiotic therapy, prolonged hospitalization, bed rest, exogenous pancreatic enzyme replacement, bronchodilators, blood and platelet transfusions, and high-dose steroids. A good outcome was obtained with cesarean section performed under local anesthesia at 32 weeks' gestation. Recommendations from the literature for the management of each disease are discussed.

Adult↗
PubMed1980

Pulmonary artery flow-directed catheter use in the obstetric patient.

Pulmonary artery flow-directed (Swan-Ganz) catheters permit continuous central hemodynamic monitoring of unstable patients. They provide important information about left ventricular function, because left ventricular end-diastolic pressure is reflected by measurement of the pulmonary capillary wedge pressure. Furthermore, thermodilution-tip models permit rapid determination of cardiac output. This report presents 3 different types of problems in obstetric patients in whom management was greatly facilitated by the use of Swan-Ganz catheters.

Adult↗
PubMed1979

Ultrasound in the diagnosis of congenital anomalies.

With high-resolution ultrasound equipment, it is now possible to diagnose certain fetal anomalies in the third trimester and in some cases before the twentieth week of gestation. During a 27 month period 2,548 ultrasound scans were performed in high-risk patients. An anomaly was diagnosed in 10 of 122 second-trimester patients who were at risk for recurrent fetal defects. Fetal deformity was also found in 26 third-trimester patients. Of the 2.8% of patients found to have polyhydramnios 18% were associated with various types of anomaly. With ultrasound it was possible to examine internal fetal anatomy and to identify abnormalities of the fetal cranium, spine, chest, abdomen, and limbs. These anomalies are reviewed here in detail. Based on ultrasonically derived information, second-trimester patients can be offered information concerning the status of their fetuses at risk genetically and physicians can better manage third-trimester patients with diagnosed fetal deformities.

Amniotic Fluid↗
PubMed1979

The ultrasonic changes in the maturing placenta and their relation to fetal pulmonic maturity.

A practical classification of placental maturity changes has been developed based on a review of multiple ultrasound evaluations of placental texture over a 4 year period. This classification grades placentas from 0 to 3 according to specific ultrasonic findings at the basal and chorionic plates as well as within the substance of the organ itself. The placentas of 129 patients were graded according to this system at the time of ultrasound evaluation. Eighty-six patients had placentas classified as Grade 1 or greater and all of these had lecithin-sphingomyelin (L/S) ratio determinations performed. Mature L/S ratios (2.0) were found in 68% of Grade I (21/31), 88% of Grade II (28/32), and 100% of Grade III placentas (23/23). These results suggest a correlation between maturational changes of the placenta as seen by ultrasound and fetal pulmonic maturity as indicated by L/S ratio.

Amniotic Fluid↗
PubMed1979

Analysis of the Distribution of Potassium-stimulated Adenosine Triphosphatase Activity in Soybean Root.

The distribution of activity of a potassium-stimulated ATPase associated with the plasma membrane was determined in 4-day-old soybean roots. Changes in protein-based specific activity of the enzyme coincided with developmental changes in the root. Activity was low in the region of the root cap, increased to a maximum in the meristematic region, decreased to a minimum as cell elongation proceeded, and then increased as lateral root development began. Analysis of the data indicated that fluctuations in enzyme activity can be described by a three-phase system which can be approximated by a linear-linear-linear piece-wise regression curve. The need for constructing a biological model to describe plasma membrane development is suggested.

Journal Article↗
PubMed1979

An electron microscope comparison of plasma membrane vesicles from meristematic and mature soybean root tissue.

Plasma membrane vesicles were isolated from homogenates of meristematic and mature soybean root tissue by differential sucrose gradient centrifugation. Vesicles were positively identified by the phosphotungstic acid-chromic acid procedure (PACP). The two preparations were comparable in size class distribution, mitochondrial contamination, and per cent plasma membrane vesicles present. Purity levels were estimated to be greater than 75%. The specificity of PACP was observed for a variety of cell types from both regions. Some variability in PACP staining was offset by careful modulation of the stain protocol and was found to be independent of developmental stage in subcellular fractions. Patchy or discontinuous staining, observed in both intact tissue and in subcellular fractions from both regions, was found to be a function of stain time.

Journal Article↗
PubMed1978

The relationship between premature rupture of the membranes and the respiratory distress syndrome. An update and plan of management.

The records of 340 infants of 36 weeks' gestational age or less were reviewed to study the relationship between premature rupture of the membranes (PRM) and the development of the respiratory distress syndrome (RDS). Twins and infants of diabetic mothers were excluded from the data analysis. PRM of 16 hours or more was associated with statistically significant reduction in the incidence of RDS in infants of 31 weeks' gestational age and older. The association between PRM in excess of 16 hours and survival, however, was only statistically significant for infants of 33 weeks' gestational age and older. The implications of these results and a proposed plan of management for premature infants with PRM are discussed.

Female↗
PubMed1977

The estimation of fetal weight by computer-assisted analysis.

The need for a quick and easy method for estimating fetal weight in utero has been clearly established. Estimates by abdominal palpation and fetal hormone production have proved to be of limited value. Eight-five patients, ranging from 17 to 41 weeks' gestation, were ultrasonically scanned within 48 hours of delivery. Statistical analysis and multiple multivariant linear regressions were performed employing the BMD statistical packages. Our results show that birth weight is a logarithmic function of fetal body parameters and that the abdominal circumference has the single best correlation with the log10 birth weight. Our best linear regression with the use of two fetal dimensions (abdominal circumference and biparietal diameter) had a standard deviation of 106 grams per kilogram fetal weight. Since this derived formula is very cumbersome to manipulate, tables have been prepared with computer assistance to read the estimated fetal weight directly. Prospective estimates in 32 cases of both normal and pathologic gestations have proved to be within our expected accuracy.

Abdomen↗
PubMed1977

Prediction of intrauterine growth retardation by determination of total intrauterine volume.

Total intrauterine volume (TIUV) measurements were performed with ultrasound on 100 normal patients at different times in gestation, and a nomogram was constructed. Ninety-six patients at risk for intrauterine growth retardation (IUGR) were then examined ultrasonically. Twenty-eight of the patients in this group delivered growth-retarded babies; in 21 of these cases the TIUV was in the abnormal zone (more than 1.5 S.D. below the mean for gestational age as determined by biparietal diameter). In the remaining seven growth-retarded cases, the TIUV was in the gray zone (between 1 and 1.5 S.D. below the mean). Although 15 normal cases were in the gray zone, there was none in the abnormal zone. There were no abnormal cases in the normal zone. An explanation for the overlap in the gray zone is offered. These results strongly suggest that TIUV is an accurate predictor of IUGR.

Female↗
PubMed1976

The relationship between premature rupture of the membranes and the respiratory distress syndrome.

The records of 212 patients of 36 weeks' gestational age or less were reviewed to study the relationship between premature rupture of the membranes (PRM) and the development of the respiratory distress syndrome (RDS). PRM greater than 16 hours resulted in a statistically significant decrease of RDS in neonates of 32 weeks' gestational age or less but not in the group from 32 to 36 weeks' gestational age. However, survival was significantly improved with PRM greater than 16 hours in the latter group but not in the former. A possible explanation for this observation is offered. Black patients had a higher over-all infant mortality rate than white patients, and, although the incidence of RDS is similar in both races, it may be a more lethal condition in black patients. There was no significant difference noted between female and male infants. Sepsis was responsible for only seven deaths in this series, and three of those cases could not be etiologically related to prolonged PRM.

Amniotic Fluid↗
PubMed1976

The Marfan syndrome and pregnancy.

The patient described had the Marfan syndrome complicated by a 22-week pregnancy. Because pregnancy potentiates the cardiovascular complications of aortic aneurysm or dissection and there is a 50% risk of having a child afflicted with the disorder, this pregnancy was electively terminated by hysterotomy along with a bilateral tubal ligation. The risks of pregnancy to a woman with the Marfan syndrome are reviewed. The rationale for the method of pregnancy termination chosen is discussed.

Abortion, Therapeutic↗