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Biomedical subjects

B Abrams

Publications and source records attributed to B Abrams.

At least 55 records · Page 3Linked to original sources

Small-for-gestational-age birth: maternal predictors and comparison with risk factors of spontaneous preterm delivery in the same cohort.

Low birth weight, the primary predictor of infant mortality and morbidity, can be a result of shortened gestation (preterm delivery) or fetal growth retardation (small for gestational age). We examined the relationship between maternal characteristics and the risk of delivering a small-for-gestational age infant in 2228 women who participated in the University of California, San Diego Prenatal Nutrition Project between 1978 and 1988. A multivariate analysis indicated that significant risk factors for small for gestational age were cigarette smoking (odds ratio, 3.18), a low rate of maternal weight gain (odds ratio, 2.96), black ethnicity (odds ratio, 2.60), pregravid underweight (odds ratio, 2.36), Asian ethnicity (odds ratio, 1.88), primiparity (odds ratio, 1.85), and low maternal height (odds ratio, 1.63). These findings are contrasted with those previously published on preterm deliveries in the same cohort. We conclude that with the exception of black ethnicity and low maternal weight gain, different maternal characteristics were significantly associated with small-for-gestational-age and preterm birth in this population.

Adolescent↗

Obstetric complications with GDM. Effects of maternal weight.

Obstetric complications recorded prospectively were assessed retrospectively in 150 women with gestational diabetes mellitus (GDM) and 305 control subjects matched for age, parity, and ethnicity. Intensive diet therapy and self-monitoring of capillary blood glucose were used to obtain postprandial euglycemia; 22% of GDM subjects required insulin. GDM and control subjects were grouped by body mass index to detect any influence of maternal prepregnancy weight on outcome. Polyhydramnios, preterm labor, and pyelonephritis were not more frequent in GDM, but hypertension without proteinuria (7.3 vs. 3.3%) and preeclampsia (8 vs. 3.9%) were more frequent in GDM. The frequency of hypertensive complications in GDM was not totally attributable to being overweight. Abnormalities of labor, birth trauma, and fetal macrosomia were not more common in GDM; 6.7% of the infants of mothers with GDM weighed greater than 4200 g at birth compared with 3.6% of control infants (NS), and 10% were large for gestational age and sex compared with 6.6% of control infants (NS). Despite this, cesarean delivery was more common in GDM (35.3 vs. 22%, P less than 0.01), mostly due to significantly more cesarean births without labor.

Birth Weight↗

Dry electrolyte-balanced heparinized syringes evaluated for determining ionized calcium and other electrolytes in whole blood.

By analyzing whole blood containing no anticoagulants (uncoagulated whole blood) immediately after collection, we evaluated the relative changes in the concentrations of ionized calcium and other electrolytes in whole blood collected in dry heparinized syringes and in serum prepared from blood collected in evacuated blood-collection tubes. Using these dry heparinized syringes, we collected and analyzed whole blood that contained either 33 or 13 int. units of lithium heparin or 40 int. units of electrolyte-balanced heparin per milliliter of blood. We evaluated the effects both of these heparins at different concentrations of ionized calcium and of the incomplete filling of the syringes. We conclude that: (a) when analyzed within 2-3 min after collection, uncoagulated whole blood provides ionized calcium results unaffected by anticoagulants or cellular metabolism; (b) the preparation of serum unpredictably changes ionized calcium; (c) the use of dry electrolyte-balanced heparin virtually eliminates the interference in ionized calcium concentrations between 0.9 and 1.6 mmol/L; and (d) incomplete filling of electrolyte-balanced heparinized syringes produces no effect in syringes two-thirds full (60 int. units/mL heparin concentration) and a small effect in syringes one-third full (120 int. units/mL heparin).

Adult↗

Maternal weight gain in women with good pregnancy outcome.

The most liberal published guidelines for maternal weight gain at term suggest a range of 9-14 kg. In a cohort of 4674 women with good pregnancy outcomes who delivered at the University of California, San Francisco between 1980-1988, the lower end of the currently published weight gain range was relevant, but the upper limit of weight gain was higher. Good pregnancy outcome was defined as a vaginal birth between 37-42 weeks' gestation of a living, singleton infant of appropriate birth weight for gestational age without congenital anomalies, born to a mother who did not experience diabetes or hypertension during pregnancy. Ranges of 12-18 and 10-21 kg described 50 and 80% of the group, respectively. Mean weight gain was associated with maternal pre-pregnancy body mass, parity, and race, with the largest differences observed in overweight and obese women. The results reported here suggest that a wider range of maternal weight gain than is currently recommended is associated with good pregnancy outcome.

Adult↗

Effects of in vivo and in vitro production of lactic acid on ionized, protein-bound, and complex-bound calcium in blood.

We have studied, both in vitro and in vivo, the quantitative effects of lactic acid production on concentrations of ionized calcium, bound calcium, pH, bicarbonate, and albumin. To do so, we examined the effects of addition of aqueous solutions of either hydrochloric acid, lactic acid, or lithium lactate to blood; we studied in vitro accumulation by storing blood sealed in tubes at room temperature for 5 h, then exposing the blood to air; and we induced in vivo production of lactic acid in healthy individuals who climbed stairs for 10 min. Lactic acid evidently affects the ionized, protein-bound, and complex-bound calcium concentrations in the following ways: (a) hydrogen ions from lactic acid bind to protein, which decreases protein-bound calcium; (b) lactate chelates calcium ions from free ionized calcium and protein-bound calcium about equally; and (c) the loss of a millimole of bicarbonate, either by exposure of blood to air or by respiratory alkalosis, results in the release of about 7 mumol of calcium ions, which re-equilibrate with both the protein-bound and ionized calcium. Because lactate apparently removes calcium ions directly from albumin, our study indicates that protein-bound calcium readily provides calcium ions that buffer changes in the concentration of ionized calcium.

Acidosis, Lactic↗

Maternal weight gain and preterm delivery.

This study examined the relationship between maternal weight gain and preterm delivery in 2163 women who participated in the Prenatal Nutrition Project at the University of California, San Diego between 1978-1986. Multivariate analysis of the data indicated that the risk of spontaneous preterm birth increased 60% in women with a low rate of weight gain (less than 0.27 kg/week) compared with those with an average rate (0.27-0.52 kg/week). Women with a low rate of gain were more than twice as likely to experience a preterm delivery as those with a high gain (higher than 0.52 kg/week); the odds ratio was 2.54 and 95% confidence interval was 1.49, 4.88. This difference in weight gain appeared after 20 weeks' gestation.

Adult↗

Overweight and pregnancy complications.

The association between increased prepregnancy weight for height and seven pregnancy complications was studied in a multi-racial sample of more than 4100 recent deliveries. Body mass indices were calculated and used to classify women as average weight (90-119 percent of ideal or BMI 19.21-25.60), moderately overweight (120-135 percent ideal or BMI 25.61-28.90), and very overweight (greater than 135 percent ideal or BMI greater than 28.91) prior to pregnancy. Compared to women of average weight for height, very overweight women had a higher risk of diabetes, hypertension, pregnancy-induced hypertension and primary cesarean section delivery. Moderately overweight women were also at higher risk than average for diabetes, pregnancy-induced hypertension and primary cesarean deliveries but the relative risks were of a smaller magnitude than for very overweight women. With women of average prepregnancy body mass as reference, moderately elevated, but not significant relative risks were found for perinatal mortality in the very overweight group, for urinary tract infections in both overweight groups, and a decreased risk for anemia was found in the very overweight group. However, post-hoc power analyses indicated that the number of overweight women in the sample did not allow adequate statistical power to detect these small differences in risk. To overcome limitations associated with low statistical power, the results of three recent studies of these outcomes in very overweight pregnant women were combined and summarized using Mantel-Haenzel techniques. This second, larger analysis suggested that very overweight women are at significantly higher risk for all seven outcomes studied. Summary results for moderately overweight women could not be calculated, since only two of the studies had evaluated moderately overweight women separately. These latter results support other findings that both moderate overweight and very overweight are risk factors during pregnancy, with the highest risk occurring in the heaviest group. Although these results indicate that moderate overweight is a risk factor during pregnancy, additional studies are needed to confirm the impact of being 20-35 percent above ideal weight prior to pregnancy. The results of this analysis also imply that since the baseline incidence of many perinatal complications is low, studies relating overweight and pregnancy complications should include large enough samples of overweight women so that there is adequate statistical power to reliably detect differences in complication rates.

Adolescent↗

Clinical validation of an automated thin-film reflectance method for measurement of magnesium in serum and urine.

We evaluated an automated method for measuring total magnesium in serum, plasma, or urine that utilizes dry multilayered thin-film reagents and reflectance photometry for use on the Kodak Ektachem 400 analyzer. Comparison of magnesium results by this method and by atomic absorption revealed the following: the results on samples from a variety of patients agreed closely, the thin-film methodology was not affected by icteric, hemolyzed, or lipemic samples, and over 100 drugs studied did not interfere. Only very high concentrations of citrate and calcium affected magnesium results by this method. Both the accuracy and versatility of the thin-film method are well suited to routine, fast response, and pediatric testing in the clinical laboratory.

Autoanalysis↗

Amyotrophic lateral sclerosis. Its natural history.

ALS is the most common of the various MNDs, which also include the clinical entities of PBP, PMA, and PLS. Mean age of onset of ALS is 57 years, and there is a sex predilection for men in a ratio of 1.5:1. Area of first symptom is in the lower extremity is 36 per cent of cases, in the upper extremity in 32 per cent, and 25 per cent of patients have a bulbar onset. Motor cranial nerves in the lower brain stem from cranial nerve nuclei or corticobulbar tract degeneration are affected. This results in symptoms of speech and swallowing difficulty and emotional lability in up to 60 per cent of cases. One hundred per cent of cases have motor weakness, over 90 per cent have muscle atrophy and fasciculations, and 47 per cent have spasticity. There seems to be a pattern of progression of ALS signs and symptoms based on area of onset with LLE involvement tending to follow RLE weakness, LUE weakness following RUE onset, and RUE involvement following next in patients whose onset is bulbar. Significant numbers of ALS patients had sparing of involvement of parts of the body for follow-up times approaching 3 years. Although the majority of patients experience a deterioration that is significantly linear, seven of 28 patients or 25 per cent achieved a plateau lasting a minimum of 9 months. Survival in our series was 4.08 years for all forms of MND.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Aqueous and serum-based materials compared for use as simulated calibrators for three ionized calcium analyzers.

To determine if bias between different ionized calcium analyzers could be decreased, we analyzed 10 control fluids during a study in which ionized calcium was measured in more than 150 serum and whole-blood samples. After calibrating three ionized calcium analyzers (Radiometer ICA 1, Nova 8, and AVL 980) with the manufacturers' respective calibrators, we used the between-instrument differences of the control fluids to simulate recalibration of the analyzers during each analytical run. A filtered human serum pool containing ionized calcium at 1 mmol/L concentration, with CO2 removed and having no added buffer, was the only material that consistently decreased between-analyzer bias of both serum and whole blood. Another human serum pool containing about 1.3 mmol of ionized calcium and about 10 mmol of bicarbonate per liter was even better at minimizing analyzer biases for serum samples, but was not as effective for whole-blood samples. Some additives used to buffer pH apparently adversely affected both the accuracy and precision of some, but not other, calcium ion electrodes. We conclude that if a reference material is developed for calibration of ionized calcium analyzers, it should be tested on several analyzers for use with both serum and whole blood, and it should be at least as effective as a human serum material, such as that used here.

Calcium↗

Behavioral responses to artificial food colors.

Twenty-two young children, maintained on a diet that excluded certain foods, were challenged intermittently with a blend of seven artificial colors in a double-blind trial. Parents' observations provided the criteria of response. One child that responded mildly to the challenge and one that responded dramatically were detected. The latter, a 34-month-old female, showed a significant increase in aversive behaviors. These results further confirm previous controlled studies.

Behavior↗

Single or combination therapy of staphylococcal endocarditis in intravenous drug abusers.

Staphylococcus aureus is the commonest cause of acute endocarditis in intravenous drug abusers. In-vitro and in-vivo animal studies have found increased killing of organisms with the combination of a beta-lactam antibiotic and an aminoglycoside. These findings have created a controversy about the use of such combination therapy. We randomly treated 25 episodes of S. aureus endocarditis in intravenous drug abusers with either single or combination antibiotic regimens. Mean days to defervescence were similar in both groups: 6.3 d (SEM, 1.49 d) for the single drug group and 6.6 d (SEM, 1.02 d) for the group treated in combination with an aminoglycoside. There were no bacteriologic failures or relapses in either group. No patients needed valvular surgery, and the mortality rate was zero. Thus, it appears that single drug therapy with an appropriate beta-lactam antibiotic is adequate and appropriate in intravenous drug abusers with S. aureus endocarditis.

Adult↗

A community-wide experience with jejunoileal bypass for obesity.

The records of seventy-nine patients who had jejunoileal bypass operations for morbid obesity were reviewed. The data represent the entire experience of surgeons in the Louisville, Kentucky metropolitan area for the period studied. Retrospective evaluations of criteria for selecting patients for bypass operation, type of shunt done, and clinical results were recorded. Sixty-eight patients (86 per cent) weighed more than 100 pounds over ideal weight. Operative mortality was 5 per cent. Only 31 patients (47 per cent) were judged as having satisfactory results. Two patients died of hepatic failure and five required restoration of intestinal continuity. Comparison of this community experience with published data supports the concept that these operations are best confined to those institutions where there is special interest in the full range of medical and surgical care of obese patients.

Adolescent↗

Estimation of the volumes of multinucleate giant cells.

An estimation of the volumes of three multinucleate giant cells has been attempted by measurements of the areas of enlarged tracings of serial paraffin sections which was estimated at approximately 5 mum in scanning electron-micrographs. In addition, three-dimensional models of these tracings constructed in wax were used to estimate the volumes of the same cells by means of Archimedes' Principle. The results indicate a close correlation between the estimates derived from the two procedures and suggest that the three cells measured have a volume of the order of magnitude of 50,000 to 100,000 mum(3).

Adolescent↗