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Biomedical subjects

C Berg

Publications and source records attributed to C Berg.

At least 19 recordsLinked to original sources
PubMed1992

The effects of a single evening dose of alkaline citrate on urine composition and calcium stone formation.

The effects on urine composition and pH of a single evening dose of alkaline potassium sodium citrate were studied in healthy subjects and recurrent calcium oxalate stone formers. This treatment resulted in a prompt and significantly increased urinary pH with a duration until 10 a.m. the next day and a reduced risk of calcium oxalate crystallization between 10 p.m. and 10 a.m. In a retrospective study alkaline citrate was given in a single evening dose of 3.75 or 5 gm. to 55 patients with calcium oxalate stone disease and a total dose of 5.0 or 7.5 gm. was administered 2 or 3 times daily in 17 patients. The mean plus or minus standard deviation for duration of treatment was 3.5 +/- 1.7 years. Significantly reduced stone formation was recorded only in those on the evening dose regimen, which was associated with significant improvement of urine composition. Patients who continued to form new stones or who had growth of residual stones despite treatment also had improved urine composition but the calcium excretion and the calcium/citrate quotient remained elevated. In 4 patients with new stone formation calcium phosphate was the major component and calcium excretion was high but the concomitant increased citrate excretion resulted in a calcium/citrate quotient that was only slightly elevated. In patients forming calcium oxalate stones the only abnormality was a high calcium/citrate quotient. Because of favorable biochemical and clinical effects as well as good patient compliance with a single evening dose of alkaline citrate, this regimen appears to be an attractive alternative for long-term prevention of recurrent calcium stone formation.

Adult↗
PubMed1992

Risk, statistical inference, and the law of evidence: the use of epidemiological data in toxic tort cases.

Toxic torts are product liability cases dealing with alleged injuries due to chemical or biological hazards such as radiation, thalidomide, or Agent Orange. Toxic tort cases typically rely more heavily than other product liability cases on indirect or statistical proof of injury. There have been numerous theoretical analyses of statistical proof of injury in toxic tort cases. However, there have been only a handful of actual legal decisions regarding the use of such statistical evidence, and most of those decisions have been inconclusive. Recently, a major case from the Fifth Circuit, involving allegations that Benedectin (a morning sickness drug) caused birth defects, was decided entirely on the basis of statistical inference. This paper examines both the conceptual basis of that decision, and also the relationships among statistical inference, scientific evidence, and the rules of product liability in general.

Abnormalities, Drug-Induced↗
PubMed1991

[Insulin consumption in Norway 1975-89. How much did the change to insulin 100 cost?].

The consumption of the various types of insulin in the period 1975-89 has been examined. Norway changed from insulin U-40 to insulin U-100 on 1 April 1987. This led to a marked increase in sales of insulin. Sales from the Norwegian Medicinal Depot (the national drug wholesale monopoly) in 1989 were 23% higher than average sales for the three years preceding the change (1984-86). This increase represents a retail value of NOK 59 million. The main reason for the increase is probably a disproportionate relationship between the amount of insulin in each vial (10 ml) and the recommended deadline for using the rest of the insulin in the vial after the first withdrawal. This has most likely led to an extensive discarding of vials containing surplus insulin. Vials with a smaller volume (5 ml) and/or re-assessment of the recommended lifespan of an opened vial might decrease the amount of insulin discarded as waste.

Costs and Cost Analysis↗
PubMed1990

Effects of different doses of alkaline citrate on urine composition and crystallization of calcium oxalate.

Prophylactic treatment with alkaline citrate in patients with recurrent calcium oxalate (CaOx) stone disease results in reduced CaOx supersaturation and increased urinary citrate. The effects of a single evening dose were compared with those of two and three daily doses in six recurrent CaOx stone formers with hypercalciuria, hypocitraturia or raised calcium/citrate quotients. While on a standardized hospital diet the patients were given 7.5 g (28 mmol) of sodium potassium citrate (URALYT-U) in one, two, and three doses. Fractional urine collections during 24 hours were analyzed for pH, composition, and crystallization risk (CR). All dosage regimens had favourable effects on urinary calcium, citrate, calcium/citrate quotients, and CaOx-CR. The most sustained effect was recorded with three divided doses. Single evening doses resulted in the most pronounced effects between 22.00-06.00 h, thereby counteracting the increased risk of CaOx crystallization during that period. In terms of 24h urine composition the best effect was recorded with alkaline citrate administered three times daily, but because of the favourable response by a single evening dose between 22.00-06.00 h the assumption was made that this dosage regimen might be sufficient to reduce the risk of CaOx crystallization and stone formation. However, the validity of such an assumption can only be established by long-term clinical studies.

Calcium Oxalate↗
PubMed1990

Barriers and motivators to prenatal care among low-income women.

Substantial evidence exists which links prenatal care to improved birth outcomes. However, low-income and nonwhite women in the United States, who are at greatest risk for poor birth outcomes, continue to receive the poorest prenatal care. The purpose of this study was to identify and compare barriers and motivators to prenatal care among women who lived in low-income census tracts. The stratified sample included recently delivered white, black and American Indian women who received adequate, intermediate, and inadequate prenatal care. Interviews were conducted which focused primarily on the women's perceptions of problems in obtaining prenatal care and getting to appointments. Results indicated that women with inadequate care identified a greater number of barriers and perceived them as more severe. Psychosocial, structural, and socio-demographic factors were the major barriers, while the mother's beliefs and support from others were important motivators. The predictive power of selected barrier variables was examined by a regression analysis. These variables accounted for 50% of the variance in prenatal care use. The results affirm the complexity of prenatal care participation behavior among low-income women and the dominant influence of psychosocial factors. Comprehensive, coordinated and multidisciplinary outreach and services which address psychosocial and structural barriers are needed to improve prenatal care for low-income women.

Adult↗
PubMed1990

Nematode related spinal myelomeningitis and posterior ataxia in muskoxen (Ovibos moschatus).

In the fall of 1988 all five animals in a herd of muskoxen (Ovibos moschatus) developed clinical signs of posterior ataxia. Postmortem investigation revealed inflammatory lesions of the caudal part of the spinal cord, mainly as leptomeningitis. Nematodes were seen in close association with the lesions. Although not identified, the parasites were probably an Elaphostrongylus sp.

Animals↗
PubMed1990

Alkaline citrate in prevention of recurrent calcium oxalate stones.

Calcium oxalate (CaOx) is the most common constituent of calcium renal stones, often mixed with calcium phosphate (CaP). The recurrence rate of these stones is high and their aetiology complex. Despite new effective, less invasive methods to remove the stones, preventive treatment is often necessary to avoid recurrence. Alkaline citrate is a relatively new medical treatment reported to give a stone free rate of between 67-92 per cent in long term studies with three daily doses. The present investigation was undertaken in order to study further the risk factors in CaOx stone formation, the influence and usefulness of a single evening dose of alkaline citrate, and the value of a four hour morning urine sample in the evaluation of patients who form stones. The highest CaOx crystallisation risk (CaOx-CR) in whole urine was recorded in the pH range 4.5-5.5, with lower values above this pH. Between pH 6.5-7.5 the number of small CaP crystals was considerably increased. The crystallisation of CaOx on hydroxyapatite (HAP) was inhibited for four hours by 1 and 2% whole urine or citrate in concentrations of 1% that in normal urine. The formation of CaP crystals in a supersaturated system was considerably reduced when citrate concentrations exceeded 0.5 mmol/l. The number of medium sized (6.5-14 microns) and large crystals (15.5-27 microns) was reduced, and small crystals (3.5-5 microns) predominated at higher citrate concentrations. The correlation between the composition of 24-h urine samples and 4-h urine specimens collected between 0600-1000, from patients with CaOx stones before and during a course of alkaline citrate given as a single evening dose was good, with the best correlation recorded during treatment. These results suggest that the 4-h urine sample might be adequate for the follow up of patients treated with alkaline citrate. A total amount of 7.5 g of potassium sodium citrate (PSC) in 1, 2, and 3 doses favourably affected urine composition in patients with CaOx stones. Three doses gave the most sustained effect, and a single evening dose gave the most pronounced effect between 2200-0600. Long term treatment (mean +/- SD duration 3.5 +/- 1.7 years) of patients who formed calcium stones with PSC in a single evening dose of 3.75 or 5.0 g (n = 55) gave a stone free rate of 75 per cent, but no clinical effect was apparent when 5.0 or 7.5 g were given in two or three doses (n = 17).(ABSTRACT TRUNCATED AT 400 WORDS)

Antacids↗
PubMed1989

The effects of citrate on hydroxyapatite induced calcium oxalate crystallization and on the formation of calcium phosphate crystals.

The addition of different amounts of hydroxyapatite crystals (HAP) to a solution, metastably supersaturated with respect to calcium oxalate (CaOx) resulted in heterogenous crystallization at seed concentrations exceeding 0.2 mmol/l. The induction period varied between 1 and more than 8 h with the shortest period for a seed concentration of 2 mmol/l. Addition to the system of 1 and 2% of whole urine and citrate in concentrations corresponding to approximately 1% of that found in normal urine inhibited the crystallization for as long as 4 h. In a system supersaturated with respect to calcium phosphate (CaP) the total number of crystals was markedly reduced by citrate concentrations exceeding 0.5 mmol/l. The fractions of medium sized and large crystals were sharply reduced and small crystals predominated at higher citrate concentrations. This might indicate effects of citrate on both crystal growth and crystal aggregation. We conclude that increased citrate concentrations during treatment with alkali leads to a significant inhibition of CaOx growth on HAP as well as to a prevention of the formation of large CaP crystals from solutions supersaturated with respect to CaP.

Calcium Oxalate↗
PubMed1988

A 5S rRNA/L5 complex is a precursor to ribosome assembly in mammalian cells.

A novel 5S RNA-protein (RNP) complex in human and mouse cells has been analyzed using patient autoantibodies. The RNP is small (approximately 7S) and contains most of the nonribosome-associated 5S RNA molecules in HeLa cells. The 5S RNA in the particle is matured at its 3' end, consistent with the results of in vivo pulse-chase experiments which indicate that this RNP represents a later step in 5S biogenesis than a previously described 5S*/La protein complex. The protein moiety of the 5S RNP has been identified as ribosomal protein L5, which is known to be released from ribosomes in a complex with 5S after various treatments of the 60S subunit. Indirect immunofluorescence indicates that the L5/5S complex is concentrated in the nucleolus. L5 may therefore play a role in delivering 5S rRNA to the nucleolus for assembly into ribosomes.

Animals↗
PubMed1987

MDL 72567, a dihydropyridine calcium-antagonist, that causes vasodilation and direct sinus bradycardia.

MDL 72567 (2,6 dimethyl,3 methoxycarbonyl,4-(2-nitrophenyl), 5-(2-furoyl)1,4 dihydropyridine) was a potent antagonist of Ca2+-induced contractions in K+-depolarized taenia preparations from the guinea pig caecum (pA2 8.8 +/- 0.1). MDL 72567 was a potent displacer of [3H]nitrendipine binding from rat cortical membrane preparations (Ki 3.99 nM), indicating an effect at the dihydropyridine binding site, which is consistent with the finding that the inhibitory effects of MDL 72567 in smooth muscle were prevented by the dihydropyridine Ca2+ channel activator Bay K 8644. MDL 72567 slowed spontaneously beating rat atria preparations to a greater extent than did nifedipine, however, for a given negative inotropic effect. Furthermore, in pithed rat preparations infused with angiotensin II to elevate blood pressure, the hypotensive effects of MDL 72567 (3 nmol/kg-3 mumol/kg, intravenously, i.v.) were accompanied by bradycardia, whereas nifedipine, PY 108-068, and nicardipine lowered blood pressure without affecting heart rate. When compared with nifedipine, MDL 72567 caused less reflex tachycardia for a given fall in blood pressure, in anesthetized beagles and in conscious renal hypertensive dogs. In anesthetized dogs, MDL 72567 increased cardiac contractility at all hypotensive doses tested (30-3,000 nmol/kg, i.v.), whereas nifedipine caused profound myocardial depression at higher doses (1,000-3,000 nmol/kg, i.v.) even though the compounds had equivalent vasodilator effects. Thus, although MDL 72567 appears to cause a direct myocardial slowing that can partially offset reflex tachycardia, the compound has negligible negative inotropic effects and may therefore be useful in angina pectoris or even in congestive heart failure.

Animals↗
PubMed1987

The composition of four-hour urine samples from patients with calcium oxalate stone disease.

Urine collected during a 24-h period between 06.00 and 10.00 h from 25 patients with recurrent CaOx stone disease was analysed with respect to calcium, oxalate, magnesium, citrate and creatinine. Urinary excretion of oxalate in relation to creatinine was slightly higher in 24-h urine but the correlation between 24-h and 4-h values was good. Good correlations were also recorded for calcium and citrate, whereas a more variable result was obtained for magnesium. In terms of the risk of forming a supersaturated urine (CaOx risk index), a good correlation was observed between 24-h and 4-h urine samples, although the highest values were found in 24-h urine. As a result of a low mean urine flow between 06.00 and 10.00 h, the highest supersaturation in terms of the AP (CaOx) index was observed in these samples. When the risk of calcium oxalate crystallisation (CaOx-CR) was determined by means of the increment in oxalate concentration required for precipitation of CaOx, 7 of 11 samples had the highest values in the 4-h urine. Samples collected during a 4-h period might thus be useful in the evaluation and follow-up of CaOx stone formers and further studies will show to what extent they can replace 24-h urine collections.

Calcium↗
PubMed1986

Phase I combined modality clinical trial of alpha-2-interferon and radiotherapy.

Sixteen patients were enrolled in a Phase I study of the combined use of recombinant DNA alpha-2-interferon (IFN) and radiation therapy, conducted at the Georgetown University Hospital (GUH) from February 1, 1984 to September 20, 1985. Escalating IFN doses ranging from 2.0 X 10(6) IU/m2 to 5 X 10(6) IU/m2 were administered to groups of six patients per IFN dose level. Three patients at each dose level were treated on a 5-day-a-week schedule and three patients were treated on a 3-day-a-week schedule. Significant toxicity including dehydration, infection, deep vein thrombosis, and myocardial infarction was noted throughout in patients receiving IFN five times per week, with eight of nine requiring hospitalization during the treatment course. There was one treatment-related death. In the five-times-per-week group, only 22% of patients tolerated the full initially planned IFN dosage and 44% tolerated the full initially planned radiation dosage, compared to 100 and 86%, respectively, in the three-times-per-week group. A tolerance dose and schedule of 5.0 X 10(6) IU/m2 of alpha-2-interferon administered subcutaneously three-times-per-week in conjunction with standard radiotherapy has been identified for use in future combined modality trials.

Combined Modality Therapy↗
PubMed1986

The effect of pH on the risk of calcium oxalate crystallization in urine.

The risk of calcium oxalate (CaOx) crystallization at different pH levels was determined in urine from recurrent CaOx-stone formers and normal subjects. The highest crystallization risk was observed between pH 4.5 and 5.5. In the pH range 6.5-7.5, there was a marked increase in crystallization of calcium phosphate (CaP). The results suggest the beneficial effect of moderate alkalinization in terms of a reduced CaOx crystallization. Reduced CaOx crystallization occurs at the expense of an increased formation of CaP crystals. Whether this increases the risk of CaP-stone formation is not known, but the CaP crystals were usually small, at least below pH 7.5.

Calcium↗