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Biomedical subjects

J A Faber

Publications and source records attributed to J A Faber.

47 records · Page 3Linked to original sources
PubMed1987

Non-Gaussian distribution of differences between duplicate probing depth measurements.

The present study aims to determine the accuracy and the distribution of the error of probing depth measurements. Duplicate measurements were performed at 1069 sites in 13 subjects. Measurements in shallow pockets (less than or equal to 3 mm) were significantly (p less than 0.001) more reproducible than measurements in deep pockets (greater than 3 mm). The overall standard deviation of the measurements was 0.74 mm. Differences between duplicate measurements were not normally distributed. Differences of 2 mm or more were recorded more frequently than one would expect on basis of the standard deviation and a hypothetical normal distribution. The observed frequency of large differences (greater than or equal to 3 mm) is much higher than the theoretical change as suggested in the literature that such differences may occur as a result of the inaccurate probing measurements. This finding implies consequences for the chance of making false claims that true changes in probing depth and attachment level have occurred over time, if the claims are based on the standard deviation and the wrong assumption that the error of the measurement is normally distributed.

Adult↗
PubMed1987

Effects of calcium and magnesium intakes and feeding level during the dry period on bone resorption in dairy cows at parturition.

A study was made of the influence of low and high calcium intakes at two feeding levels (experiments 1 and 2), and of different magnesium intakes (experiment 3) during the dry period, on the cellular resorptive activity in bone of dairy cows at parturition. In experiment 1 (26 cows) the feed intake was 1.12 times maintenance and the calcium intake was either 13.0 g d-1 or 83.5 g d-1. In experiment 2 (33 cows) the feed intake was 1.9 times maintenance and the calcium intake was either 26.4 g d-1 or 87.2 g d-1. In experiment 3 the cows feed intake was 1.4 times maintenance, the calcium intake was 71 to 72 g d-1 and the magnesium intake was either 16.6 g d-1 or 71.0 g d-1. Bone biopsies were taken from the tuber coxae between three and eight hours after parturition. In experiment 1 the cellular resorptive activity in bone from older cows was higher in the cows receiving the low calcium diet. In experiment 2 the differences between the bone resorptive activities of the two groups were small. In experiment 3 the bone resorptive activity was lower in the cows with a deficient supply of magnesium. There were significant relationships in young cows, but not in older cows, between the cellular resorptive activity in bone and the rate of calcium mobilisation measured biochemically. These results suggest that in older dairy cows bone resorption makes only a minor contribution to the total rate of calcium mobilisation at parturition and is therefore of minor importance for the prevention of periparturient hypocalcaemia.

Animals↗
PubMed1986

Effects of low and high calcium intake prepartum on calcium mobilization rate around parturition in dairy cows.

Forty-one dairy cows were fed a low (LCa-13 g/d) and a high (HCa-83.5 g/d) calcium ration in the 8 weeks prior to parturition and the effect on the Ca mobilization rate around parturition was studied. Plasma Ca values were stable in the LCa group around parturition. In the older cows of the HCa group a very slight decrease in the mean plasma Ca was observed: 2.58 mmol/l at 12-36 h ante partum decreased to 2.38 mmol/l at parturition. Hypocalcaemia, which commonly occurs around parturition, did not occur in 40 of the cows. A subclinical hypocalcaemia (1.8 mmol/l) occurred in one cow (parity 10) from the HCa group. To assess the efficiency of Ca mobilization, a severe hypocalcaemia (1.0 mmol/l) with clinical signs was induced by means of Na2EDTA infusion (0.90 mmol/min), starting at 10 h post-partum. The older cows in the LCa group required more Na2EDTA than those in the HCa group. Higher urinary hydroxyproline excretion in the week before parturition in the LCa than in the HCa group suggested a higher bone turnover. Plasma PTH levels around parturition were not significantly different between the groups. The amount of colostrum milked out in the first 10 h post-partum did not influence Ca homeostasis around parturition. The results contradict those of many other experiments in which hypocalcaemia was observed in cows ingesting high levels of Ca. It is concluded that the restricted feed intake prepartum possibly had a favourable effect on Ca homeostasis.

Animals↗
PubMed1986

Growth response to human growth hormone treatment in children with partial and total growth hormone deficiency.

The growth response during the first and second years of human growth hormone (hGH) treatment was studied in 14 prepubertal children with so-called "partial" GH deficiency (peak GH between 8 and 15 mU/l) and compared to 28 prepubertal children with "total" GH deficiency (peak GH less than 8 mU/l). There was no difference in growth acceleration between children with partial and total GH deficiency, when initial covariables were taken into account. In a stepwise multiple regression analysis initial stature, pre-treatment growth velocity and skinfold thickness were shown to be most related to growth response, but after exclusion of 3 children with a genetic form of total GH deficiency and partial TSH deficiency this relationship was lost. GH levels during provocation tests and auxological criteria have a poor predictive value for growth response to hGH therapy.

Anthropometry↗
PubMed1986

Renography: prediction of blood pressure after dilatation of renal artery stenosis.

In 60 patients with hypertension and unilateral renal artery stenosis (URAS) radio-hippuran renograms were performed before and 6 weeks after anatomically adequate percutaneous transluminal angioplasty (PTA). Two characteristics of the renographic curves have been analyzed: the difference in time to peak (DTP) between the affected and contralateral kidneys, which would be expected to be positive in blood flow impairment, and the relative hippuran uptake (RHU) in the second minute by the affected kidney as compared with the total uptake by both kidneys: this would be less than 50% in the case of stenosis. Before PTA, both variables were predominantly abnormal. The DTP did not predict the blood pressure response to PTA. The group of patients with a RHU between 25 and 45% comprised all cured patients and predicted a more favorable response of the blood pressure than a RHU of less than 25% and especially more than 45% which group contained 83% patients whose blood pressure failed to respond after PTA. After PTA the DTP did normalize in the majority of patients, but this was not related to the blood pressure response. The RHU increased in patients in whom it had been low initially, but frequently remained low (less than 45%). The increase of the RHU was significantly higher in patients with a favorable blood pressure response. Pretreatment with captopril did intensify the abnormal curves of hippuran and of DTPA renograms in 6 patients with URAS who did respond favorably to PTA. There was no such deterioration in 2 patients whose blood pressure did not change sufficiently after PTA or in 4 patients without renal artery stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1985

[The usefulness of the refractometer in the assessment of colostrum and various factors affecting serum gamma globulin levels in newborn calves].

The effects of a number of factors on the concentration of gamma globulins in the serum of newborn calves were studied in 181 calves from six different dairy farms as was also the use of the refractometer test in controlling the ingestion of colostrum. The refractometer test was found to be reliable in controlling the concentration of gamma globulins in the serum of calves up to the sixth day of life. The factors 'time the first colostrum was ingested', 'amount of first colostrum ingested' and the 'concentration of gamma globulins in the colostrum' were found to account for 23.5 per cent of the variations in serum gamma globulin concentration; this became 42.4 per cent when the 'system of administration' and the 'farm-bound factors' were also taken into account. The first colostrum is best ingested when it is offered in a pail or bottle provided with a nipple. Calves of heifers were found to show a lower concentration of gamma globulins in the serum than did calves of older cows.

Animal Feed↗
PubMed1981

Absence of seasonal variation of estrogen receptor levels in human breast cancer tissue.

The concentration of estrogen receptors was measured in 979 human primary breast cancer tumors obtained during 4 consecutive years. Of these tumors, 631 were classified receptor positive and originated from 212 premenopausal and 419 postmenopausal patients. A modified EORTC procedure was used to quantify the receptor content. Several statistical analyses were performed on the data from the premenopausal and postmenopausal patients separately and on the combined data. The results of these analyses do not support the existence of any periodicity in the estrogen receptor level which is significant and consistent from year to year.

Breast Neoplasms↗
PubMed1979

Oral contraceptive use and secondary amenorrhea.

Among 1099 patients seen over an 8-year period for amenorrhea or oligomenorrhea, 115 (10.5%) had developed amenorrhea after ceasing oral contraception. These patients were the subject of a special study. Those who were treated received either clomiphene alone, hMG/hCG therapy, or both. There was no correlation between the incidence of either spontaneous or treatment-induced ovulation and menstruation and the duration of use of oral contraception, previous parity, or the nature of prior menstrual cycles. The incidence of treatment-induced resumption of menses was essentially the same as that for spontaneous resumption. An average duration of 30 months of oral contraceptive use did not significantly affect urinary excretion levels of estrogens and gonadotropins.

Amenorrhea↗
PubMedDate not supplied

Comparison of skull circumference and linear measurements with CSF volume MR measurements in hydrocephalus.

In children with hydrocephalus, accurate and reproducible estimation of the presence, severity, and course of the condition is of paramount importance for both clinical and scientific purposes. In this study, 30 hydrocephalic patients were assessed with a number of commonly used methods, such as occipitofrontal skull circumference (SC) measurements, Evans ratio (ER), and bicaudate index (BCI), as well as, for comparison, another ratio of linear measurements [ventricle-skull ratio (VSR)] and MR measurements of total intracranial CSF volume. In repeated CSF volume measurements in healthy volunteers, the MR method appeared to be accurate and reproducible. This technique was simpler and easier in application, requiring less interaction than comparable MR techniques described by others. The variation coefficients were within the same range. In increased CSF volumes, our technique can be recommended; in very small CSF volumes, another technique is more adequate. Direct assessment of CSF volume as a measure of hydrocephalus was preferable over derived estimations for scientific purposes and may function as a gold standard against which to evaluate other techniques that are easier to apply clinically. In comparison, SC measurements were poor; CSF volume changes were not reflected in SC changes. VSR was preferable over ER and BCI, because it correlated more closely with CSF volume.

Cerebrospinal Fluid↗
PubMedDate not supplied

Intra- and inter-observer variability in the assessment of testicular descent.

Measurements of the distance between the testis and the pubic tubercle have been used to differentiate retractile testes from "real" cryptorchidism and to measure the effect of therapy. The intra- and inter-observer variation of these measurements was determined in 21 boys with incompletely descended testes treated with placebo. Patients were investigated in supine and squatting position, before and during moderate caudal traction. In squatting position the average distance is 20 mm greater than in supine position. The intra-observer SD is approximately 10 mm. It is doubtful if quantitative measurements can be used to define retractile testes. The wide prediction intervals should be taken into account in interpreting results of therapy.

Administration, Intranasal↗