PubMed Health⌕ Search

Biomedical subjects

G Toss

Publications and source records attributed to G Toss.

33 records · Page 2Linked to original sources

The gene responsible for familial hypocalciuric hypercalcemia maps to chromosome 3q in four unrelated families.

Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant syndrome of unknown aetiology characterized by lifelong elevation in serum calcium concentration and low urinary calcium excretion. These features suggest that the causal gene is important for maintenance of extracellular calcium homeostasis by the parathyroid gland and kidney. To identify the chromosomal location of FHH gene(s), we clinically evaluated 114 individuals in four unrelated affected families and performed linkage analyses. The disease gene mapped to the long arm of chromosome 3 in each family (combined maximum multipoint lod score = 20.67). We suggest that this is the predominant FHH locus and anticipate that identification of the FHH gene will improve our understanding of the molecular basis for physiologic and pathologic regulation of calcium.

Base Sequence↗

Effect of calcium intake vs. other life-style factors on bone mass.

Several life-style factors are known to or have been suggested to interact with calcium metabolism and bone turnover. Immobilization or a sedentary life-style may result in substantial bone loss, and physical exercise may increase bone mass, to different extents in different parts of the skeleton. Excessive training and/or slimming may lead to amenorrhoea, which is in turn complicated by rapid bone loss. While calcium supplementation probably cannot override the negative calcium balance induced by immobilization or amenorrhoea, the calcium requirement may be enhanced during recovery from these states. A high body mass index may to some extent protect against bone loss, particularly in post-menopausal women. Tobacco smoking and high alcohol consumption are probably detrimental to bone mass. Insufficient exposure to daylight and/or insufficient vitamin D intake occur mainly in infants and elderly people, and may impair calcium balance and cause rickets, osteomalacia or osteoporosis. Whether high intake of caffeine, protein, phosphate or fibre is detrimental to the bone mass has not yet been clarified. In many populations smoking and consumption of alcohol or caffeine are negatively correlated with calcium intake, and this exemplifies a source of confounding factors. Increased attention would be paid to important life-style factors during investigations of calcium requirements in different sex and age categories.

Bone Density↗

Parathyroid hormone-related peptide, measured by a midmolecule radioimmunoassay, in various hypercalcaemic and normocalcaemic conditions.

The diagnosis of humoral hypercalcaemia of malignancy often presents considerable clinical problems. We have studied parathyroid hormone-related peptide (PTHrP) in serum from patients with humoral hypercalcaemia of malignancy (N = 22), hypercalcaemia of malignancy with skeletal metastases (17), histologically confirmed primary hyperparathyroidism (21) and hypercalcaemic patients with various benign diseases (9). PTHrP measurements were also made in normocalcaemic patients with various malignancies (23), endocrine diseases (13), sarcoidosis (22) and chronic renal failure (17). PTHrP was measured by a novel radioimmunoassay using rabbit antibodies directed towards the midregion of the molecule. Immuno- or silica cartridge extraction of serum before radioimmunoassay enabled us to measure PTHrP in all samples, which may add further information about circulating forms of PTHrP. PTHrP was clearly elevated in patients with humoral hypercalcaemia of malignancy (5.0 +/- 4.7 pmol/l) (mean +/- SD, N = 12) and when the kidney function was impaired (4.0 +/- 0.9 pmol/l) (N = 15) (silica cartridge extraction), whether the subject was hypercalcaemic or not. Some patients with endocrine diseases, including two with primary hyperparathyroidism, had slightly elevated serum PTHrP concentrations, while they were normal in sarcoidosis. In healthy subjects the levels were 1.1 +/- 0.5 pmol/l (N = 15) after immunoextraction and 0.8 +/- 0.2 pmol/l (N = 33) after silica cartridge extraction.

Aged↗

Increased hip-fracture incidence in the county of Ostergötland, Sweden, 1940-1986, with forecasts up to the year 2000: an epidemiological study.

The incidence of hip fractures in the county of Ostergötland in Sweden has increased dramatically from 1940 to 1986, mainly due to an increase in age-specific incidence of trochanteric fractures. The increase is most pronounced in people over 80 but is present even in age groups down to 50 years. If the age-specific incidence rates continue to increase, and the population of the elderly grows in accordance with the forecast, there will be 70% more hip fractures in the year 2000 than in 1985.

Age Factors↗

Prevalence of protein-energy malnutrition in a large population of elderly people at home.

The prevalence of protein-energy malnutrition (PEM) was examined in 1206 randomly selected elderly people aged 65 to 80 years living in their own homes. Nutritional assessment was based on weight loss, weight index, triceps skin fold, arm muscle circumference, serum albumin and prealbumin, and delayed cutaneous hypersensitivity (DCH) reaction. The prevalence of PEM was 5 per cent. If people with signs of inflammation were excluded, the prevalence of PEM was 3.5 per cent. When other nutritional indices, used by other authors among hospitalized patients, were applied to our sample prevalence values from 2.6 to 4.1 per cent were obtained. the prevalence was not related to sex or age. DCH increased the sensitivity of the screening method but causes of anergy other than PEM must be taken into account. It is concluded that PEM, in a degree shown to impair the prognosis at hospital, does occur among elderly people at home in an industrialized country.

Aged↗

Familial hypocalciuric hypercalcaemia: a study of four kindreds.

Four kindreds with hereditary hypercalcaemia have been investigated. Thirty-seven of 72 subjects examined had hypercalcaemia with an autosomal dominant pattern of inheritance. Hypercalcaemic patients had total serum calcium of 2.91 +/- 0.12 mmol l-1. Serum parathyroid hormone (PTH) was normal while daily urinary calcium excretion was subnormal (below 2.5 mmol) in 45%. Comparison with an age-matched group of patients with primary hyperparathyroidism gave a small overlap regarding serum human PTH, urinary calcium and the ratio between calcium clearance and creatinine clearance. Family screening therefore is of diagnostic importance. Twelve subjects had been subjected to parathyroid surgery before the correct diagnosis was settled, none of the cases had an adenoma. Three patients became normocalcaemic and the others had persistent hypercalcaemia. One male non-abuser had seven episodes of acute pancreatitis before surgery and none after. The findings in all four kindreds are compatible with familial hypocalciuric hypercalcaemia (FHH). This hereditary disorder of unknown aetiology, therefore, also exists in Scandinavia. It is of importance to consider FHH in the differential diagnosis of hypercalcaemia, since this disorder usually has a benign prognosis if untreated.

Calcium↗

Serum concentrations of 25-hydroxyvitamin D and vitamin D-binding protein in elderly people. Effects of institutionalization, protein-energy malnutrition and inflammation.

Serum concentrations of 25-hydroxyvitamin D (25-OH-D) and vitamin D-binding protein (DBP) were measured in institutionalized and non-institutionalized elderly people. The institutionalized subjects were found to have low serum 25-OH-D in confirmation of other studies, but their serum DBP levels were similar to those found in non-institutionalized elderly subjects. Serum DBP concentrations were slightly higher in elderly females than in males, while no age dependence was found for DBP. Elderly people with protein-energy malnutrition who lived in their own homes had slightly reduced serum DBP and 25-OH-D levels. Elderly subjects with infections or other diseases causing acute inflammation, as indicated by an elevated serum haptoglobin and C-reactive protein, had normal levels of DBP.

Adult↗

Serum levels of 25-hydroxyvitamin D in adults and elderly humans after a prophylactic dose of vitamin D2.

Vitamin D2 was administered orally as a single dose (2 mg) to 19 elderly subjects and 17 young adults. The maximum elevation of serum 25-hydroxyvitamin D was significantly greater in young than in elderly subjects. To evaluate intestinal absorption we also measured serum levels of vitamin D2 5 h after the given dose. A vitamin A absorption test was also performed simultaneously. Small differences between young and old subjects were seen with respect to serum vitamin D2 or vitamin A increments. In both groups the serum level of 25-hydroxyvitamin D was still elevated above initial level 60 days after a dose was given. No side effects, nor any change in serum calcium ion activity were noted during this period. These results speak in favour of the use of intermittent large doses of vitamin D2 as a prophylaxis against vitamin D deficiency in the elderly.

Adult↗

Delayed hypersensitivity response and vitamin D deficiency.

The relationship between delayed hypersensitivity and serum levels of 25-hydroxyvitamin D were examined in sixty-three elderly people. After intracutaneous injection of five recall antigens (Candida, mumps, PPD, tricophyton and varidase) nineteen subjects showed no response (anergy), seven showed only a weak reaction (relative anergy), and thirty-seven a normal reaction. In the anergic group mean serum level of 25-hydroxyvitamin D was significantly lower than in the group with normal immunoreactivity. Five subjects with anergy and serum 25-hydroxyvitamin D below 20 nmol/l were treated with oral vitamin D or UV irradiation for two to three months, after which both the serum 25-hydroxyvitamin D levels and the delayed hypersensitivity were normalized. In a non-treated group anergy persisted in seven out of nine patients in a second skin test. We conclude that anergy in the delayed hypersensitivity skin test in humans may in some cases be due to vitamin D deficiency.

25-Hydroxyvitamin D 2↗

Oral vitamin D and ultraviolet radiation for the prevention of vitamin D deficiency in the elderly.

Different methods for the prevention and treatment of vitamin D deficiency were studied in 42 institutionalized elderly people. One group received ultraviolet radiation (UVR) on a large area of the body surface once a week for three months. The results were compared with those in groups receiving either 450 IU vitamin D2 together with 420 mg calcium daily, 420 mg calcium alone, or no treatment. A significant increase in serum 25-hydroxyvitamin D was obtained with UVR. A similar increase was obtained with oral vitamin D2. A small but significant decrease in serum alkaline phosphatase was observed in subjects receiving vitamin D and calcium or calcium alone. No effects on serum phosphate, urinary cyclic adenosine monophosphate and urinary calcium were seen. Though brief UVR at one-week intervals is an efficient and safe method for prevention of vitamin D deficiency in the elderly, it is in our experience time-consuming for the ward staff and thus less convenient than oral vitamin D supplementation.

Administration, Oral↗

Trivariate evaluation of a thyroid hormone panel in clinical practice compared with multiple univariate evaluation.

The results from 510 consecutive routine determinations of free thyroxine index, free triiodothyronine index and thyrotropin were evaluated using both a trivariate reference region and the combined three univariate reference intervals. The results from 109 patients were discordant when evaluated by both the trivariate and the triple univariate reference regions. In 108 of these subjects the hormone results were found to be abnormal by the triple univariate evaluation method but normal when the trivariate reference region was used. The latter evaluation was in accordance with the clinical findings of the patients, who were euthyroid as evaluated from the 105 medical records we could trace. In one subject, clinically euthyroid, trivariate evaluation misclassified the patient as abnormal in contrast to the classical univariate evaluation. We conclude that the trivariate evaluation method was in better agreement with the clinical diagnosis of the patients and should be used in the routine evaluation of trivariate data in order to diminish the number of false abnormal results.

Humans↗

Vitamin D deficiency in welfare institutions for the aged.

Serum concentrations of 25-OH-D in a group of 47 elderly people (70--94 years old) living in homes for the aged were lower than those in a matched control group living in their homes. No differences between the groups were noted in serum ionized calcium, alkaline phosphatase, inorganic phosphate, magnesium or parathyroid hormone. The low serum concentration of 25-OH-D may be due to less outdoor activities and/or a smaller dietary vitamin D intake in the institutionalized group. The importance of preserving an adequate vitamin D status in geriatric patients is emphasized.

Aged↗