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Biomedical subjects

L Singer

Publications and source records attributed to L Singer.

At least 55 records · Page 3Linked to original sources
PubMed1987

An investigation of calcium intake, 1-alpha(OH)D3, and etidronate on bone.

The synthetic metabolite of vitamin D3 [1 alpha(OH)D3] caused a significant plasma calcium elevation in rats only when dietary calcium was low. Animals given the low calcium diet (0.005%) had lower plasma parathyroid hormone (PTH) levels when the diet contained 1 alpha(OH)D3 and significantly higher levels than animals on a high calcium (0.95%) diet, with or without the vitamin. The nutritional stress of a low calcium diet without 1 alpha(OH)D3 resulted in a prolonged severe hypocalcemia and elevated serum PTH levels. A higher ash, phosphate, and calcium content was found in the bones of animals fed the high calcium diet, with no vitamin D3 that were given etidronate (EHDP). When animals received the same calcium diet with 1 alpha(OH)D3 supplementation, EHDP administration increased the percentage of bone ash but had no effect on ash weight. 1 alpha(OH)D3 or EHDP did not affect ash weight, dry fat free weight, and percentage of ash of bone of animals receiving a low calcium diet. The percentage of calcium and phosphorus in bone ash was similar among all groups, although the amounts per humerus were characteristically related to the calcium intake. There was approximately 20-25% less bone mineral and calcium and phosphorus in the humeri of low calcium intake animals than in animals provided an adequate dietary calcium.

Animals↗
PubMed1987

Acid diffusion analysis of different forms of fluoride in human dental plaque.

Fluoride concentration was determined by: (a) extraction with diphenylsilanediol after combustion of the plaque in an oxygen bomb; (b) acid diffusion from 0.5 M HClO4 for 16 h at room temperature; (c) acid diffusion from 4.6 M HClO4 for 16 h at room temperature; and (d) acid diffusion from 18 M H2SO4 for 16 h at 60 degrees C. The total fluoride was determined by all the diffusion procedures, and there was no evidence of a large proportion of the plaque fluoride being released only after treatment with strong acid (18 M H2SO4). When approx. 10 mg of plaque was extracted three times with 0.1 ml 0.5 M HClO4, 81 per cent of the fluoride was released by one 5 min extraction. After three extractions no further fluoride was detected when the residue was diffused from 4.6 M HClO4 for 16 h at room temperature. When larger plaque samples (21-66 mg) were extracted four times with 1 ml 0.5 M HClO4, 85 per cent of the fluoride was in the first extract, and none was detected in the fourth. Treatment of the residue with 18 M H2SO4 for 16 h at 60 degrees C released a further, small amount which may constitute up to 3 per cent of the total plaque fluoride. Thus the amount of tightly-bound plaque fluoride, released only by treatment with strong acid, is much smaller than previously believed.

Dental Plaque↗
PubMed1987

Compliance with long-term lithium treatment in major affective disorders.

Compliance with long-term lithium treatment was studied retrospectively in 73 patients suffering from major affective disorders. It was assessed during the first two years treatment by monitoring plasma lithium levels every 6 weeks. 5 patients stopped the lithium treatment before the first two years were up. Of the 68 remaining patients, only 32 (47%) were thought to be complying perfectly. Most of the failures with lithium (11 patients out of 15) were observed in non-compliant patients. The main factors accounting for non-compliance were a low intellectual level, cognitive deficit, affective relapses and traits of personality disorders; on the other hand, neither the age nor the sex of the patients, nor the polarity, the severity or the duration of the affective disorders, nor the modalities or side effects of the treatment seemed to have any bearing on compliance.

Adult↗
PubMed1987

Long-term hospitalization of nonorganic failure-to-thrive infants: patient characteristics and hospital course.

Hospitalization remains an available treatment option for nonorganic failure-to-thrive (NOFT) infants, even though it separates an infant from his/her caregiver and may further weaken an already impaired caregiver-infant attachment. Long-term hospitalization as an intervention for NOFT has been noted, but not documented, in previous reports in the literature. The present study describes patient characteristics, growth in hospital, and length of stay among a group of NOFT infants referred for and treated through long-term hospitalization. The study also investigated the effects of an additional family-oriented outpatient intervention program on hospital course and discharge planning for these infants. Results of the study found that NOFT infants referred for extended hospitalization were an impoverished group, with the majority showing below average development functioning. One-third presented with "interactional" failure-to-thrive, in which biological vulnerability coexisted with, but was not causative of, the infant's poor growth. Infants averaged 18 weeks in hospital, but lengths of stay differed, dependent on the presence of an outpatient treatment group and additional medical problems with both factors reliably associated with shorter lengths of stay. Infants in county welfare custody who did not receive additional outpatient intervention were also more likely to be placed outside the parental home at discharge.

Analysis of Variance↗
PubMed1986

Fluoride concentration in amniotic fluid and fetal cord and maternal plasma.

Fluoride concentrations were determined in plasma of 50 pregnant women, 44 samples of amniotic fluid and fetal cord blood of 29 fetuses at various stages of normal pregnancies, from an area with a relatively low water fluoride (less than 0.5 ppm) content. The mean concentrations of fluoride from maternal plasma, cord plasma and amniotic fluid (+/- S.D.) were 0.033 +/- 0.003, 0.028 +/- 0.005 and 0.017 +/- 0.003 ppm, respectively. Maternal and fetal plasma fluoride concentrations did not differ significantly. In the older age group fetal cord plasma fluoride concentration was significantly lower than maternal plasma levels (0.012 +/- 0.08 ppm vs. 0.023 +/- 0.001, respectively; p less than 0.05). Amniotic fluid fluoride levels were significantly higher at term than in midtrimester pregnancy, 0.017 +/- 0.0018 vs. 0.010 +/- 0.009 ppm (P less than 0.05), respectively. This higher concentration may imply higher fetal urinary excretion of fluoride at term due to the lower sequestration of fluoride as the process of bone calcification is more complete.

Adolescent↗
PubMed1986

Long-term hospitalization of failure-to-thrive infants: developmental outcome at three years.

The present study documented later developmental outcome in a group of 29 failure-to-thrive (FTT) infants who received extended hospitalization in infancy as an intervention for their growth failure. All infants were seen at approximately 3 years of age and were given standardized assessments of intellectual and physical development. A standard interview documented demographic variables, health problems, placements subsequent to hospitalization and additional psychological and medical treatment. Infants were divided into three groups dependent on medical and treatment factors. Means and percentages of occurrence of outcome variables were compared through either one-way ANOVAS or single sample chi-square tests with post hoc analyses. Correlational analyses were used to understand the relationships between outcome and relevant demographic, medical, and treatment variables. In general, the infants manifest persistent intellectual delays at follow-up despite maintenance of weight gains achieved during early hospitalization. More than half the group suffered from chronic health problems. A large percentage of infants had been removed from parental custody at the time of follow-up. Several demographic, medical, and treatment factors bore moderate relationships to developmental outcome. Infants who achieved more optimal growth tended to be full-term at birth, later born and without a question of physical abuse in their social histories. Intellectual functioning was related only to parental and caretaker socioeconomic status. Infants placed in foster care were unlikely to return to their families of origin. The findings suggest the need for further investigation into the determinants and outcome of extended hospitalization as a treatment for FTT.

Child Abuse↗
PubMed1986

[Transient delusional disorders and schizophrenia. Comparative catamnestic study of 2 groups of patients].

The authors investigated, in 1982, the situation of two groups of patients who had spent at least 8 days in the Psychiatric Clinic of the Strasbourg University Hospital in 1972, one group of whom had been diagnosed as suffering from "bouffée délirante aiguë" (B.D.A.), and another, from schizophrenia. In 1982, the former consisted of 43 people, 26 women and 17 men, and the latter of 72, 24 women and 48 men. The catamnesis was elaborated on the basis of social security files and information provided by physicians. All possible precautions were taken to protect professional secrecy and patients' anonymity. The data collected were subjectived to statistical analysis to establish correlations between certain variables and, on the basis of these variables, the traditional French classification was compared with that of the D.S.M. III. The outcome of patients suffering from B.D.A. was significantly better than those considered as schizophrenics. However, in 11 out of 26 patients with a B.D.A. diagnosis in 1972, there was an evolution towards schizophrenia, whereas 10 of the 44 schizophrenics displayed no handicap 10 years later. As regards the comparison between the prognostic values of the traditional French classification and D.S.M. III, the latter appeared more restrictive as to the diagnosis of schizophrenia with perhaps a clearer prognostic value. This catamnistic study further reinforces the arguments in favour of the existence of the B.D.A. as a clinical category. Further in-depth research in the genetic, biological and psychopathological fields should yield answers to the many questions still remaining.

Delusions↗
PubMed1985

Promotion of bone dissolution by excessive fluoride in acidic buffer solution.

In order to quantitatively examine fluoride uptake by bone and the effect on its chemical and physical properties, rat bone was incubated in acidic buffer solutions (pH 5) with fluoride concentrations of 0-1000 ppm F. After 1 wk incubation, there was a substantial increase in the crystallinity of the bone mineral with increasing fluoride concentration in the solution. The calcium concentration in the solutions used for incubation decreased dramatically, with increased levels of fluoride in the solution, approaching a plateau. The phosphate concentration initially decreased, with increasing levels of fluoride in proportion to the decrease of calcium concentration, and then increased when the fluoride concentration of the solution was above 200-300 ppm. These phenomena, when considered with X-ray diffraction data, reflected the formation of CaF2. The increase of the phosphate concentration in the solution suggests that the presence of excessive fluoride in the acidic buffer solution may promote the dissolution of soluble bone apatites, in spite of the dissolution-preventive activity of fluoride.

Animals↗
PubMed1985

Dietary fluoride intake of 6-month and 2-year-old children in four dietary regions of the United States.

Based upon the analysis of 44 market basket food collections, the average daily dietary fluoride intakes of 6-mo-old and 2-yr-old children residing in cities with water fluoride levels of 0.05 to 1.04 ppm were determined. In cities with greater than 0.7 ppm fluoride in the drinking water, a 6-mo-old child (infant) and a 2-yr-old child (toddler) had mean dietary fluoride intakes of 0.418 mg/day (0.052 mg/kg body weight) and 0.621 mg/day (0.050 mg/kg body weight) respectively. The data indicate that the average dietary fluoride intake of infants and toddlers did not exceed 0.08 mg/kg, and in all but three cases was within or below the optimum range of 0.05-0.07 mg/kg. The ingestion of fluoride-containing dentifrice or milk formula diluted with fluoridated water may result in intake levels exceeding that associated with the development of dental fluorosis (0.1 mg F/kg body wt).

Child, Preschool↗
PubMed1985

Dietary fluoride intake of 15-19-year-old male adults residing in the United States.

The average daily dietary fluoride intakes of 15-to-19-year-old males were estimated from the analysis of 24 FDA "market basket" food collections made from 1975 to 1982. The data indicate that 15-to-19-year-old males residing in fluoridated (greater than 0.7 ppm) cities had an average daily dietary fluoride intake of 1.85 mg/day when the diet provided an estimated caloric intake of 11.72 megajoules (2800 calories). In non-fluoridated cities, with less than 0.3 ppm in the drinking water, the average dietary fluoride intake was 0.86 mg/day. The beverages and drinking water contributed an average of 75 +/- 2% of the daily dietary fluoride intake.

Adolescent↗