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Biomedical subjects

H Rico

Publications and source records attributed to H Rico.

At least 163 records · Page 9Linked to original sources
PubMed1987

Formation of a new cell wall by protoplasts of Candida albicans: effect of papulacandin B, tunicamycin and Nikkomycin.

Incorporation of polysaccharides into the walls of regenerating protoplasts of Candida albicans was followed in the presence of papulacandin B, tunicamycin and nikkomycin. With the first drug, chitin was incorporated normally whereas incorporation of glucans and mannoproteins was significantly decreased. Tunicamycin decreased incorporation of all wall polymers when added at the beginning of the regeneration process but blocked only mannan and alkali-insoluble glucan incorporation when added after 5 h. Nikkomycin inhibited chitin synthesis, and the walls formed by the protoplasts were enriched in alkali-soluble glucan. Pulse-chase experiments suggested that a precursor-product relationship between the alkali-soluble and alkali-insoluble glucans existed in the wall. The results obtained with the antibiotics were confirmed and extended by cytological studies using wheat-germ agglutinin labelled with colloidal gold and concanavalin A-ferritin as specific markers of chitin and mannoproteins respectively. The results support the idea that regeneration of walls by protoplasts occurs in two steps: firstly, a chitin microfibrillar skeleton is formed, and in a later step glucan-mannoprotein complexes are added to the growing structure. The chitin skeleton probably allows the orderly spatial arrangement of the other polymers giving rise to the regenerated cell wall.

Aminoglycosides↗
PubMed1987

Calcitonin-induced hypocalcaemia as a possible index of osteoclastic activity in patients with chronic renal failure.

It has been suggested that the intensity of hypocalcaemic response to the administration of calcitonin may reflect the degree of osteoclastic activity and thus the state of the parathyroid function. We have performed the calcitonin test in 14 healthy volunteers and in 17 patients with chronic renal failure undergoing haemodialysis. The test involved the intramuscular injection of 100 MRC units of synthetic salmon calcitonin, serum calcium being determined before and after 5 h of the injections of the hormone. In 7 of the patients, the test was repeated using intranasal administration by means of a spray of calcitonin. In renal patients, serum calcium fell from 9.73 +/- 0.76 to 7.88 +/- 1.01 mg/dl (1.85 +/- 0.67 mg/dl). In the control group, serum calcium fell from 9.51 +/- 0.56 to 8.89 +/- 0.34 mg/dl (0.62 +/- 0.35 mg/dl). The calcium fall in renal patients was significantly greater than in the control group (p less than 0.001). In patients there was a statistically significant correlation between the fall in serum calcium and the level of alkaline phosphatase, but no with the serum concentration of immunoreactive parathormone (C-Terminal). After intranasal calcitonin, serum calcium fell from 9.81 +/- 0.55 to 8.83 +/- 0.72 mg/dl (1.42 +/- 0.42 mg/dl), a reduction comparable to that obtained after the intramuscular injection of the hormone in the same patients (1.84 +/- 0.69 mg/dl). These results provide evidence of an increase in osteoclastic activity in chronic renal failure, perhaps reflecting parathyroid hyperfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Low serum osteocalcin in acute alcohol intoxication: a direct toxic effect of alcohol on osteoblasts.

A direct effect of alcohol on bone cells has not been convincingly demonstrated, but numerous studies have postulated that alcohol inhibits osteoblastic activity. Since osteoblasts synthesize osteocalcin, we studied the serum levels of this protein in 15 patients with acute alcoholic intoxication to determine if alcohol has an effect on these cells, whether direct or indirect. We found lower osteocalcin levels in our alcoholics than in 15 normal individuals of similar age and sex (3.1 +/- 1.0 vs. 6.6 +/- 0.8 ng/ml; P less than 0.0001), evidence of the influence of alcohol on osteoblasts. This effect seems to be direct rather than mediated.

Alcoholism↗
PubMed1986

Dysplasia epiphysialis multiplex: a case report.

The clinical features of a new patient with dysplasia epiphysialis multiplex are reported. Similar symptoms are present in four members of the family. This disease seems to be inherited as a simple dominant Mendelian trait. The disease mainly affects the epiphyses of the long bone and nearly always begins with pain in the hip-joint. Our patient presented radiological features of osteoporosis with calciotropic hormones within normal range and with a low trabecular bone volume. This histomorphometric bone study shows a low bone turnover osteoporosis, which suggests an altered trabecular development with a greater clinical expression in the epiphyses.

Adult↗
PubMed1986

Oncogenous osteomalacia: a new case secondary to a malignant tumor.

A case of oncogenous osteomalacia secondary to a fibrous malignant histiocytoma in a 31-year-old male is described. The patient also demonstrated a lupuslike anticoagulant. Clinical signs of osteomalacia preceded by 9 years those of the tumor, a feature occurring in only 8% of these malignancies. Surgical resection of the tumor and surrounding tissues was followed by a clinical improvement and a return to normal of serum phosphorus and tubular reabsorption of phosphate, though the lupuslike anticoagulant persisted. This first description of a fibrous malignant histiocytoma with associated osteomalacia and lupuslike anticoagulant makes compulsory the inclusion of these syndromes among those already described that may appear with this tumor.

Adult↗
PubMed1986

Changes in the plasma membrane of regenerating protoplasts of Candida albicans as revealed by freeze-fracture electron microscopy.

Modifications occurring in the plasma membrane and their relationship to newly synthesized microfibrils were examined in regenerating protoplasts of Candida albicans by freeze-fracture electron microscopy. Freshly prepared protoplasts showed no residual wall material, and long invaginations covered the surface of the plasma membrane. Analysis of the external face (E-face) of the plasma membrane showed a significant decrease in the number of intramembranous particles (IMP) in comparison with the original cells. After 40 min incubation in regeneration medium, newly synthesized microfibrils which seemed to originate from protrusions in the plasma membrane were observed. The plasma membrane showed important modifications with respect to IMP. After 3 h 45 min, the cells were covered by an abnormal wall which showed isolated fibrils partially embedded in the matrix material. The plasma membrane of these partially regenerated protoplasts was similar to that of original cells. After 8 h, regeneration of the protoplasts seemed to be complete as no differences from the original cells were detected in the plasma membrane or the wall. Calcofluor white altered the deposition of wall polymers during regeneration, but did not modify the plasma membrane of the protoplasts.

Candida albicans↗
PubMed1985

Adult hypophosphatemic osteomalacia: report of two cases.

Two cases of late hypophosphatemic osteomalacia are described: a male aged 30 who had the disease since he was 22 and a woman of 23 who had the disease since she was 14. Both presented with myopathy and bone pain, and showed hypophosphatemia, hyperglycinuria, reduced tubular phosphate reabsorption (TPR), increased hydroxyprolinuria and normal iPTH and iCT values. Radiologically the male had no Looser's zones and the woman did. Bone biopsy confirmed hypophosphatemic osteomalacia. Both cases were treated with vitamin D and oral phosphate and no improvement was observed. When treatment with 25(OH)D3 was initiated, no improvement was seen and afterwards this was combined with treatment using 1.25(OH)2D3 and from this time on a clinical improvement of the myopathy became evident in both patients. In the woman, healing of the bone lesions occurred at the same time as that of the myopathy, whereas in the male the bone lesions became worse. Healing of the myopathy was only obtained when treatment with 1.25(OH)2D3 was begun. Both patients had reduced values of 2.3 erythrocytic DPG and low level of serum phosphorus when the myopathy was cured, which suggests a lack of effect of 2.3 DPG or serum phosphorus as a cause of the myopathy. Although this had been attributed to a deficiency in the function of 25(OH)D3, the response to 1.25(OH)2D3 and due to the effects of this metabolite on calcium transport in muscle, suggests that the myopathy which occurs in late hypophosphatemic osteomalacia is a result of deficiency or resistance to the muscular effect of this metabolite. We cannot explain the lack of bone healing in the man and further therapeutic studies are required.

Adolescent↗
PubMed1985

Increased blood cortisol in alcoholic patients with aseptic necrosis of the femoral head.

Although aseptic necrosis of the femoral head secondary to alcoholism is a very frequent entity, its etiology remains unknown. The same pathogenic mechanism is thought to be shared both by aseptic necrosis secondary to alcoholism and steroid therapy. Since alcohol stimulates adrenal steroid secretion, we have studied serum cortisol and urinary free-cortisol levels in 8 patients with aseptic necrosis of the femoral head due to alcoholism and compared them with those found in 8 age-matched patients with aseptic necrosis of idiopathic origin. Serum cortisol levels and urinary free-cortisol levels were significantly higher in the alcoholic than in the idiopathic group: serum 227 +/- 21.7 vs 154 +/- 22.1 ng/ml, P less than 0.001; urine 0.20 +/- 0.002 vs 0.13 +/- 0.04 micrograms/mg Cr/day, P less than 0.001. The data indicate that alcohol-induced aseptic necrosis of the femoral head results, at least in part, from increased circulating cortisol.

Adult↗
PubMed1984

Lack of hormonal changes in postmenopausal women of equal weight with and without osteoporosis, including relation to time of menopause.

The hormonal variations in postmenopausal osteoporosis are not precisely defined. The duration of the menopause and other factors, such as the weight of the patients, may be of significance. Having a basic criterion of uniformity in weight, sixty postmenopausal women were studied in regard to the following aspects: urinary hydroxyproline, estrone, estradiol, parathyroid hormone, thyroxine, triiodothyronine, thyroid stimulating hormone, cortisol and metacarpal cortical area/total area. They were divided into: Group A: 15 patients with osteoporosis and five years since menopause; Group B: 15 patients without osteoporosis (age-matched with group A); Group C: 15 patients with osteoporosis and more than ten years since menopause; and Group D: 15 patients without osteoporosis (age-matched with Group C). In the group with postmenopausal osteoporosis (A and C) there is a significant increase in urinary hydroxyproline/creatinine and a significant decrease of the cortical area/total area when we compared them with age-matched groups. The hormonal values do not vary significantly among the four groups. Ours results indicate an increase of bone resorption as a cause of postmenopausal osteoporosis. The hormonal variations, if any, cannot be related to basal values.

Age Factors↗