Mechanism of the Formation of Organic Derivatives of gamma-Zirconium Phosphate by Topotactic Reactions with Phosphonic Acids in Water and Water-Acetone Media

The rates of the topotactic reactions between gamma-zirconium phosphate and phenylphosphonic acid in water and water-acetone mixtures at various temperatures were investigated. The slow rates of the process in aqueous medium or in water-acetone mixtures at temperatures lower than 50 degrees C were attributed to a slow interdiffusion of O(2)P(OH)(2)(-) and O(2)P(OH)(C(6)H(5))(-) groups in the interlayer region of gamma-ZrP. Similar to ion-exchange processes, the replacement begins in the external part of the interlayer region and progresses toward the central region with the formation of an advancing phase boundary. In water-acetone mixtures at temperatures higher than 60 degrees C an exfoliation of gamma-ZrP was found. Thus, the initial process is very fast since the substitution can take place directly on the surface of the exfoliated gamma-lamellae. However, after a certain degree of substitution, a flocculation of the colloidal dispersion, which slows down the rate of the further topotactic substitution, was observed. Some considerations on the topotactic substitution occurring on the surface of the exfoliated lamellae and on the mechanism of the diffusion of the exchanging species in the interlayer region are also reported.

Serum leptin concentration, obesity, and insulin resistance in Western Samoans: cross sectional study

OBJECTIVE

To measure serum leptin concentrations in the Polynesian population of Western Samoa and to examine epidemiological associations of leptin with anthropometric, demographic, behavioural, and metabolic factors in this population with a high prevalence of obesity and non-insulin dependent diabetes mellitus.

DESIGN

Cross sectional study, leptin concentration being measured in a subgroup of a population based sample.

SUBJECTS

240 Polynesian men and women aged 28-74 years were selected to cover the full range of age, body mass index, and glucose tolerance.

MAIN OUTCOME MEASUREMENTS

Serum leptin, insulin, and glucose concentrations; anthropometric measures; physical activity; and area of residence.

RESULTS

Leptin concentrations were correlated with body mass index (r = 0.80 in men, 0.79 in women) and waist circumference (r = 0.82 in men, 0.78 in women) but less so with waist to hip ratio. At any body mass index, leptin concentration was higher in women than men (geometric mean adjusted for body mass index 15.3 v 3.6 pg/l, P < 0.001). Leptin concentration also correlated with fasting insulin concentration (r = 0.63 in men, 0.64 in women) and insulin concentration 2 hours after a glucose load (r = 0.58 in men, 0.52 in women). These associations remained significant after controlling for body mass index; effects of physical activity and of rural or urban living on leptin concentration were eliminated after adjusting for obesity, except values remained high in urban men. 78% of variance in leptin was explained by a model including fasting insulin concentration, sex, body mass index, and a body mass index by sex interaction term. Similar results were obtained if waist circumference replaced body mass index.

CONCLUSIONS

The strong relation of leptin with obesity is consistent with leptin production being proportional of mass to adipose tissue. The relation with insulin independent of body mass index suggests a possible role for leptin in insulin resistance or hyperinsulinaemia.

[Introduction of definite molecular weight heparan sulfate in a protocol of prevention of deep venous thrombosis in prosthetic orthopedic surgery]

Use of definite molecular weight heparan sulphate in a protocol for the prevention of deep venous thrombosis in the total joint replacement surgery. The authors propose a working protocol for the prevention of deep venous thrombosis in prosthetic orthopaedic surgery. It requires that integration of pharmacological, anaesthesiological, rheological and physiokinesitherapic measures, it has permitted a very good prevention of thromboembolic disease and it is well-tolerated and safe. The protocol requires: peripheral anaesthesia (sub-arachnoidal block), pre and post-operative pharmacological treatment with heparan-sulphate of a fixed molecular weight, haemodilution with maintenance of the haematocrit at no more than 30%, early physiokinesitherapy associated with the use of elastic stockings graduated tension. The fifty patients treated with this protocol were controlled during the pre-operative and post-operative stage and one month later and no thrombo-embolic complications resulted.

Glutathione S-transferase M1 genotype and age-related cataracts. Lack of association in an Italian population

PURPOSE

To investigate possible associations between the gene number and allelic forms of glutathione S-transferase M1 (GSTM1) and the occurrence of nucleic and cortical age-related cataracts.

METHODS

Patients with cortical cataract, nuclear cataract, mixed and cortical cataract, and no cataract were sytematically selected from subjects evaluated in the Italian-American Study of the Natural History of Age-Related Cataract. The patients were typed for the A, B, and null alleles of GSTM1 using a variation of the amplification refractory mutation system.

RESULTS

Forty-nine percent of patients (50/102) with cortical cataracts, 45% (13/29) with nuclear cataracts, 51% (36/71) with mixed nuclear and cortical cataracts, and 50% of controls (49/98) were homozygous for the null GSTM1 allele. Twenty-five percent of patients (26/102) with cortical cataracts, 24% (7/29) with nuclear cataracts, 31% with mixed nuclear and cortical cataracts, and 27% of controls (26/98) displayed only the A allele for GSTM1. Twenty-four percent of patients (24/102) with cortical cataract, 24% (7/29) with nuclear cataracts, 14% (10/71) with mixed nuclear and cortical cataract, and 18% of controls showed only the B allele for GSTM1. Two percent of patients (2/102) with cortical cataracts, 7% (2/29) with nuclear cataracts, 4% (3/71) with mixed nuclear and cortical cataracts, and 5% of controls (5/98) showed both A and B alleles for GSTM1.

CONCLUSIONS

No associations between the GSTM1 alleles, including the null allele, and cataracts were detected in this study.

Impact of heavy metals on mass and energy flux within the decomposition process in deciduous forests

: Laboratory experiments on microbial decomposition and on the contribution of diplopods to organic matter decomposition in soil were combined with field studies to reveal the major points of heavy metal effects on the leaf litter decomposition process. The study focused on the accumulation of organic litter material in heavy metal-contaminated soils. Microbial decomposition of freshly fallen leaves remained quantitatively unaffected by artificial lead contamination (1000 mg kg(-1)). The same was true for further decomposed leaf litter material, provided that the breakdown of this material was not influenced by faunal components. Although nutrient absorption in diplopods is affected by high lead contents in the food, this effect alone, however, was shown not to be sufficient for the massive deceleration of the decomposition process under heavy metal influence which could not only be observed in the field but occurred in microcosm studies as well. Reduced reproduction and lower activity of the diplopods most likely were responsible for the observation that lead-influenced diplopods enhanced microbial activity in soil only in a lesser degree than uncontaminated animals did. This effect is assigned to represent the main reason for decreased decomposition rates and the subsequent accumulation of organic material in heavy metal-contaminated soils.

A hydroxyquinone with amine oxidase activity: preparation and properties

The preparation and some properties of a hydroxyquinone showing an amine oxidase-like activity are described. The compound, 2-hydroxy-5-methyl-1,4-benzoquinone, oxidizes a wide range of primary amines, both benzylic and non-benzylic, at the expenses of molecular oxygen in the presence of Cu2+ ions, and reacts with hydrazine derivatives leading to stable, inactive adducts. This behaviour is similar to that of 2,4,5-trihydroxyphenylalanine quinone-containing amine oxidases and therefore the present compound could be a useful model to understand the reaction mechanism of those enzymes.

Lens sodium channels are inactivated by anti-MIP26 antibodies

Sodium-specific channels can be functionally identified in phosphatidylcholine liposomes incorporating detergent-solubilized membrane proteins from pig lens epithelium and outer cortex. The transport of sodium is saturable, specific and protease-sensitive. MIP26 was identified in the solubilized membrane fraction and in the liposomes by means of Western blot analysis. Pre-treatment of liposomes with anti-MIP26 antiserum abolished the transport of sodium. These data indicate that MIP26 is associated to a sodium selective transport activity.

Enzyme activities in human lens epithelium of age-related cataract

PURPOSE

To investigate associations between enzyme activity of glutathione reductase (GR) with and without added flavin adenine dinucleotide (FAD), glutathione peroxidase (GPX), and 6-phosphogluconic dehydrogenase (6PGDH) in the lens epithelium collected at surgery, and some nutritional and biochemical variables determined in the same individuals during the Italian-American Case-Control Study of age-related cataract.

METHODS

One hundred eighty-three epithelium capsule samples were collected from 174 patients undergoing surgery. Data on enzyme activity were obtained from 52 samples for 6-PGDH and from 53 samples for GR and for GPX. The Lens Opacity Classification System II was used to classify and grade cataracts.

RESULTS

No correlation was found between enzyme activity in lens epithelium and the same enzymatic activity in erythrocytes (with the exception of a negative correlation between lens and erythrocyte 6PGDH activity), or the type and severity of cataract. No correlation was found between lens GPX activity and plasma selenium and between lens GR activation coefficient (GRAC) and riboflavin intake. Lens GR with added FAD and lens GRAC were significantly correlated to plasma vitamin E level. Lens GRAC was positively correlated to a nutritional vitamin index.

CONCLUSIONS

Present data stress the difficulty in verifying the assumption that biochemical indices collected on plasma and on erythrocyte actually reflect the status of these factors in the lens itself.

Normal splanchnic but impaired peripheral insulin-stimulated glucose uptake in cirrhosis

The site of impaired glucose uptake in cirrhosis is uncertain. We therefore performed hyperglycemic clamps (glucose 10 mmol/L) in 10 patients with compensated alcoholic cirrhosis and impaired glucose tolerance and in six control subjects. Muscle glucose uptake was estimated in patients and controls with the forearm technique. In the cirrhotic subjects splanchnic glucose uptake was measured with hepatic vein catheterization and primed continuous infusions of indocyanine green and [6-3H]glucose. To assess insulin-independent glucose uptake and the effects of elevated nonesterified fatty acid levels on glucose uptake, we repeated the study with somatostatin to induce insulin deficiency and a nicotinic acid analog, acipimox, to inhibit lipolysis. Substrate disposal was assessed on indirect calorimetry. Despite similar stimulated insulin levels, total glucose utilization was lower in the cirrhotic subjects (3.9 +/- 0.3 vs. 8.8 +/- 1.7 mg/kg/min, p = 0.006). This deficiency was accounted for by lower nonoxidative glucose disposal (1.2 +/- 0.2 vs. 5.8 +/- 1.6 mg/kg/min, p = 0.002). Forearm glucose uptake was lower in the cirrhotic subjects (0.39 +/- 0.06 vs. 1.21 +/- 0.3 mg/100 ml/min, p = 0.001). However, splanchnic glucose uptake at 1.59 +/- 0.14 mg/kg/min was similar to that reported in other studies of normal subjects. Insulin-independent glucose uptake was normal, and acipimox had no effect on total or forearm glucose utilization. Glucose intolerance in cirrhosis is characterized by impaired peripheral insulin-stimulated non-oxidative glucose disposal. The high nonesterified fatty acid levels seen in cirrhosis most likely do not contribute to this defect. Splanchnic glucose uptake is normal in cirrhosis.

[Meteoropathy: a syndrome continuously on the increase]

The authors describe the different kinds of meteoropathies, pointing out how these disorders are becoming ever more frequent in countries belonging to the consumer and welfare society due to the progressive lowering of body resistance and immunologic responses. These "unfavourable meteosyndromes", as meteoropathies should be called, develop when wave disturbances arrive, and are more manifest and persistent in subjects with neurologic disturbances, i.e. in the presence of anxiety, stress, hypertension, coronary artery disease, arthropathy, hyperthyroidism, etc. The different moments in which meteoropathies are more frequent and the possible therapies are also discussed.

[Climate and psychosomatic medicine]

In the last few years, psychosomatic medicine has accomplished very important and interesting analyses of several medical syndromes. On the contrary, medical climatology, even with the development of new tools for climate research, has remained linked to old ideas which need to be revised in order to keep pace with the latest discoveries in this field. It is therefore desirable to undertake research on the action of different climates and microclimates on the human organism, and also to take into account the patients, tendencies and aspirations, because "the climate that will yield the best results is the climate the patient likes best". In conclusion, taking into account a patient's personality and aspirations, thermal therapies and climate treatments may be coupled. As a matter of fact, in our country it is possible to find spas with the same kind of waters but with completely different climates.

[The use of high-field magnetic resonance in the follow-up of patients with mechanic aortic valve prosthesis and composite aortic tubular prosthesis]

Eleven patients who had undergone cardiac surgery were studied by means of high-field MR imaging (1.5 T). Six patients had had aortic root and valve replaced with a Björk-Shiley (BS) composite tubular aortic graft prosthesis for acute dissection of ascending aorta. In the other 5 patients with rheumatic calcific aortic disease, the valve had been replaced with a BS prosthesis. As a whole, MRI studies were 14. Previous evaluations of magnetic field effects had seem carried out ex vivo on both BS valves and BS composite prostheses, on surgical ligation clips (Tantalium and Stainless) and on stainless wires for sternal closure. In 4 patients (2 BS composite grafts and 2 BS valves) MRI diagnosed chronic dissection of both arch and descending aorta. In 1 of them, with a BS valve, associated localized acute dissection of ascending aorta was observed. In 3 patients with BS composite grafts, MRI revealed pseudo-aneurysms (including a thrombosed one) at the graft level. In one case MRI was repeated 4 times and was very helpful in monitoring the pseudo-aneurysm. MRI showed pericardial hematoma in 2 patients with BS grafts and paravalvular abscess in a case with BS valve. In one patient with BS valve fast-imaging MR revealed severe aortic regurgitation. No adverse reactions were demonstrated on MR images of prosthetic implants. MRI artifacts were insignificant with the spin-echo technique, while the fast-imaging technique showed clear image distortion at the valve level.

Ultrastructural analysis of apoptosis induced by the monoclonal antibody anti-APO-1 on a lymphoblastoid B cell line

Apoptosis (programmed cell death) is the most common form of death in eukaryotic cells. We recently described a monoclonal antibody, anti-APO-1, which induces apoptosis of cells from the human B-lymphoblastoid line SKW 6.4 and of cells from a variety of other human lymphoid cell lines. This model of apoptosis was now studied ultrastructurally. SKW 6.4 cells undergoing apoptosis showed the following morphological changes: condensation of the cytoplasm and karyoplasm, formation of large electron-opaque aggregates of the chromatin lining the nuclear membrane, "blebbing" of the cell membrane at an early stage of apoptosis, and dilatation of the mitochondria. Two hours after adding anti-APO-1, the nuclear membrane was ruptured. Occasionally, large vesicular enlargement of endoplasmic reticulum or Golgi appeared in the cytoplasm. Finally, total breakdown of all cell membranes and cellular disintegration was observed.

[Obesity and mental disorders in childhood]

The aim of the present study was to establish the prevalence and the type of psychiatric disturbances in a group of 42 obese children (18 boys aged from 6.8 to 13.8 years and 24 girls aged from 2.8 to 15.4 years; weight excess mean +/- 1SD 146.7 +/- 17.4%) and to evaluate the efficacy of a psychological approach of obesity in childhood. The children were in a normal caloric diet and they were encouraged to reach a "target weight" in a given period of time. 22 children were randomly assigned the "analyzed" group (auxological, alimentary and psychological evaluation) and 20 to the "control" group (auxological and alimentary assessment). The psychological evaluation was performed in 20 children (the parents of two children refused to give their consent) by the following tests: creative drawing test; draw a man test (Machover); draw a tree test (Koch); draw a family test (Co-man); Rorschach's test; TAT (Thematic Apperception Test) or, in the younger, the Düss's tales. The results of these psychological tests have been communicated to the patients and or parents. The children were followed for a period of 7 months. We found in 8 children (40%) personality disturbances (which were severe in two cases) and a psychological support was started. The observed main types of disturbances were depression and anxiety. Both were due to a missing harmony between their parents, to a difficult relationship either with their mother or with other children, and to the bad child's opinion of himself. In 4 subjects a psychological support associated with diet promoted a slow, progressive and continuous weight loss.(ABSTRACT TRUNCATED AT 250 WORDS)

[Progressive familial myoclonic epilepsy with bulbo-spinal amyotrophy. Clinical, electrophysiological study, and biopsy of a case]

Two brothers with Progressive myoclonic epilepsy and Juvenile bulbar and spinal atrophy had clinical, neurophysiological study and muscle biopsy. The EEG and polygraphic findings included progressive slowing of the background activity, spontaneous fast generalised spike- and wave discharges and photosensitivity. The EMG revealed pathological spontaneous activity as well as motor unit potentials diminished in number and increased in amplitude and duration; while VDCS and VDCM were normal. Results of muscle biopsy showed no represented "ragged red fibers" with the modified Trichrome stain, while grouped small caliber angular fibers of both histochemical type were visible with the myofibrillar ATPase reaction, but type 2 fibers predominated amongst the atrophic ones. Serum and urine metabolic measurement and lysosomal enzyme activities in leukocytes were all normal. We feel that the reported case might represent a familial syndrome not previously recognized showing non-specific degenerative changes with neuropathological examination. This disorder is similar only to the case reported by Lance J.W. and Ewans W.A. in 1984 "Progressive myoclonic epilepsy, nerve deafness and muscular atrophy".