Nocturnal calcium, phosphorus and parathyroid hormone in the diagnosis of concealed and subclinical hypoparathyroidism

CONTEXT: Circadian rhythms of plasma parathyroid hormone (PTH) show peak values at night, whereas serum calcium levels peak in the evening and display a nadir at night. HYPOTHESES: Subclinical hypoparathyroidism (HPT) can be detected by utilizing the knowledge of diurnal variations. Thalassemia major (TM) may provide a model system of subclinical HPT. DESIGN: Nocturnal plasma PTH and serum calcium values were determined in 13 TM patients with normal morning serum calcium levels as compared with the corresponding values in eight healthy control subjects. RESULTS: Six patients with TM presented a nadir serum calcium level of 8.3 mg/dl or lower (hypoCa TM) at 0200 h, whereas the remaining seven showed nadir levels of 8.4 mg/dl or higher (normoCa TM). Patients with hypoCa TM displayed a drop between peak and nadir of 1.2 +/- 0.5 mg/dl as compared with a considerably smaller fall of 0.3 +/- 0.7 mg/dl in control subjects (P < 0.05). NormoCa TM patients experienced comparable nocturnal variation to that of control subjects. Patients from both the hypoCa and normoCa TM groups presented significantly lower nocturnal PTH levels than those of control subjects and lost the nocturnal PTH variation characteristic of healthy subjects. A plot of all serum calcium against plasma PTH levels provides a clear distinction of the three groups. CONCLUSIONS: All 13 daytime normocalcemic TM patients presented a certain degree of HPT. The hypoCa TM group displayed a concealed HPT detected in all, except the morning sampling, whereas normoCa TM patients experienced sub clinical HPT observed in the absence of nocturnal HPT variation. Nocturnal measurements of serum minerals thus enhance the sensitivity of HPT diagnosis.     

A pilot study of iron depletion as adjuvant therapy in chronic hepatitis C patients not responding to interferon

The aim of this study was to assess the efficacy of iron depletion obtained by phlebotomy to enhance interferon response in 11 patients who had failed to respond to a standard 3-month interferon treatment. Despite a significant effect on serum aminotransferase levels, there was no effect on viremia, and iron depletion was unable to trigger interferon response.     

Utilisation of the method of Kalman filtering for performing the on-line computation of background metabolism in the free-moving, free-feeding rat

Since 1984, we have utilized a metabolic device in which activity and food intake are measured at 10-second intervals, in relation to the respiratory exchanges in the rat (indirect calorimetry). To solve the problem of quantifying precisely the metabolic cost of activity, we have developed models of the diffusion of the cells' respiratory exchanges in the rat and in the metabolic chamber until they reached the gas analyzers. The predictions of these models have been used to feed a process of numerical filtering that computed an estimation of the energy cost of activity, and an estimation of the value of the part of the total metabolism that was not due to the cost of the muscular contractions. This later component of metabolism has been named background metabolism to be clearly distinguished from the true resting metabolism measured during resting periods. In this paper, two models of diffusion of the cell's respiratory exchanges are described, and examples of the computation of the background metabolism by the process of Kalman filtering are shown.     

Human fetuses are able to mount an adultlike CD8 T-cell response

Fetal/neonatal immune responses generally are considered to be immature and weaker than that of adults. We have studied the cord-blood T cells of newborns congenitally infected with Trypanosoma cruzi, the protozoan agent of Chagas disease. Our data demonstrate a predominant activation of CD8 T cells expressing activation markers and armed to mediate effector functions. The analysis of the T-cell receptor beta chain variable repertoire shows the oligoclonal expansion of these T lymphocytes, indicating that activation was driven by parasite antigens. Indeed, we have detected parasite-specific CD8 T cells secreting interferon-gamma after coincubation with live T cruzi. This response is enhanced in the presence of recombinant interleukin-15, which limits the T-cell spontaneous apoptosis. These findings point out that the fetal immune system is more competent than previously appreciated, since fetuses exposed to live pathogens are able to develop an adultlike immune CD8 T-cell response.     

Assessing the validity of existing dental sealant quality measures

Background

Although sealants are highly effective in preventing caries in children, placement rates continue to be low. The authors’ goals were to implement and assess the performance of 2 existing sealant quality measures against a manual audit of charts at 4 dental institutions and to identify measurement gaps that may be filled by using data from electronic health records.

Hydrolyzed collagen improves bone status and prevents bone loss in ovariectomized C3H/HeN mice

Summary

This study evaluates the effect of hydrolyzed collagen (HC) on bone health of ovariectomized mice (OVX) at different ages. Twenty-six weeks after the OVX procedure, HC ingestion was still able to improve significantly bone mineral density (BMD) and some femur biomechanical parameters. Moreover, HC ingestion for 1?month before surgery prevented BMD decrease.

Introduction

HC can play an important role in preserving BMD before osteoporosis appears. The aim of this study was to evaluate the effect of HC on bone health of ovariectomized mice at different ages.

Methods

Female C3H mice were either OVX at 3 or 6?months and fed for 6?months (first experiment) or 3?months (second experiment) with diet including 0, 10, or 25?g/kg of HC. In the second experiment, one group received HC 1?month before surgery, and two groups received the supplementation immediately after surgery, one fed ad libitum and the other by gavage. Mice treated with raloxifene were used as a positive control. BMD, femur intrinsic and extrinsic biomechanical properties, and type I collagen C-terminal telopeptide were measured after 12 and 26?weeks. Food intake and spontaneous physical activity were also recorded.

Results

The OVX procedure increased body weight, while food intake decreased, thus suggesting that resting metabolism was decreased. Ingestion of 25?g/kg of HC for 3 or 6?months reduced bone loss significantly in, respectively, 3- and 6-month-old OVX mice. The lowest HC concentration was less efficient. HC ingestion for 3?months is as efficient as raloxifene to protect 3-month-old OVX mice from bone loss. Our results also demonstrated that HC ingestion before surgery prevented the BMD decreases.

Conclusion

This study confirms that dietary collagen reduces bone loss in OVX mice by increasing the diameter of the cortical areas of femurs and can have a preventive effect.