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Biomedical subjects

G Costanzo

Publications and source records attributed to G Costanzo.

At least 19 recordsLinked to original sources
PubMed1991

A single-reaction method for DNA sequence determination.

A chemical method for the determination of DNA sequence is presented. Heating of DNA, labeled at a single 3' extremity, in the presence of formamide results in efficient cleavage of phosphodiester bonds 3' of A, G, and C residues. The relative efficiency is A = G greater than C. The bias between A and G is solved by a simple pretreatment (photoreaction in methylene blue) followed by heating in formamide. The entire procedure does not require any intermediate purification step or handling of hazardous chemicals and allows determination of the sequence on only two electrophoretic lanes. Its simplicity and rapidity favor automatization.

Base Sequence↗
PubMed1990

Attraction, phasing and neighbour effects of histone octamers on curved DNA.

Nucleosome core particles were reconstituted on various DNA fragments containing a Crithidia fasciculata kinetoplast curved tract. The results show that, on curved DNA, nucleosome core particles form six- to sevenfold preferentially, relative to bulk sequences. The preferential deposition occurs at multiple periodic positions, whose distribution reveals a unique rotational setting of DNA with respect to the histone octamer surface and whose average periodicity is 10.26 +/- 0.04. Evidence is provided for a context effect in histone octamer deposition: octamers bound to a segment of curved DNA influence the positions of neighbour octamers. Taken together, the preferential formation of nucleosome core particles and the influence on the localization of neighbouring particles suggest for intrinsically bent sequences the biologically relevant role of organizers of nucleosomal arrays.

Animals↗
PubMed1990

Effects of calcium channel blockers on platelet aggregation and thromboxane A2 formation: an in vivo double blind randomized study.

In this double blind cross over study against placebo the in vivo effects of diltiazem, nifedipine and verapamil on platelet aggregation and Thromboxane A2 (TxA2) formation were evaluated in eighteen healthy adults. No significant inhibition of platelet aggregation or TxA2 formation was found either after acute or short term (8 days) administration of the three calcium channel blockers at the usual therapeutical dosages. Our study indicate that diltiazem, nifedipine and verapamil are unable to significantly affect platelet aggregation and TxA2 formation in healthy subjects.

Adult↗
PubMed1990

Indications for early surgery in cases of lumbar and dorsolumbar scoliosis: the role of vertebral rotation.

There are very few objective criteria for the choice between conservative and surgical treatment of lumbar and dorsolumbar scoliosis ranging from 40 to 50 degrees. We reviewed the long-term results obtained in 76 patients treated with plaster braces because they had refused surgical treatment; in 56% of the cases a nearly 10 degree gain was maintained after the onset of treatment; all of the cases which showed improvement presented a reduction in the curve by at least half and rotation by at least one-third in tests in suspension or in bending, and this was maintained in plaster. In cases where the long-term results were poor, however, rotation did not change. In conclusion, of the many parameters examined, only a combined assessment of the reducibility of both the Cobb angle and of rotation provides a valid indication for the treatment of lumbar and dorsolumbar curves ranging from 40 to 50 degrees.

Adolescent↗
PubMed1989

Linkage reduction allows reconstitution of nucleosomes on DNA microdomains.

We have established an experimental system for reconstitution of an individual nucleosome on a closed DNA microdomain (operationally defined as a DNA domain of a size so small as to be unable to establish titratable superhelical turns). The microdomain (185 base-pairs (bp), composed of 128 bp encompassing the central part of the Saccharomyces cerevisiae ADH II promoter plus 57 bp of a polylinker) was obtained by ligation under conditions that produced three circularized forms characterized by different linkage numbers. These linkomers were tested for nucleosome reconstitution with S. cerevisiae histones. It was observed that only microcircles with linkage reduction (delta Lk = 1 or 2) could form a nucleosome, as defined by protection of a 145(+/- 2) bp DNA fragment from micrococcal nuclease, relaxed forms (open or closed circles) could not.

Base Composition↗
PubMed1989

Neurological deficits secondary to spinal deformities: their treatment and results in 13 patients.

We report the results of surgical treatment in 13 patients operated on for compression of the spinal cord secondary to kyphosis or kyphoscoliosis between 1977 and 1985. In every case, an anterior decompression of the cord by transthoracic or thoracoabdominal route was followed in the same operation by anterior stabilization. Posterior fusion with Harrington's instrumentation was performed 15-20 days later. Neurological recovery was complete in 8 patients (61.5%) and partial in 4 (30.7%), while 1 patient died (7.6%). We review the relevant published work.

Adult↗
PubMed1989

[Variations in the serum levels of thyroid hormones and TSH after intake of a dose of L-thyroxine in euthyroid subjects and in adequately-treated hypothyroid patients].

The aim of the present study was to determine whether the temporary variations in blood thyroid hormone levels secondary to a therapeutic dose administration of L-thyroxine observed in adequately treated hypothyroid patients also occur in spontaneously euthyroid subjects under analogous conditions. Serum levels of T3, T4, FT3, FT4 and TSH were measured over 6 hours following a single oral administration of L-thyroxine (dosage 85 mcg/mq body surface area) in a group of 18 euthyroid volunteers and 8 hypothyroid patients adequately compensated with replacement therapy. In the euthyroid subjects there was a significant increase in T4 and a significant fall in TSH values at 60', while a significant decrease in FT3 and FT4 as compared to initial values was observed at 120'. In the treated hypothyroid patients serum T3 and T4 increased at 120', while FT4 concentrations, already significantly higher at 120', still remained higher than initial levels at 360'. The different behaviour of the hypothyroid patients, in spite of being compensated with therapeutic doses of L-thyroxine, reflects the persistence of a thyroid-metabolic condition substantially different to the physiological feature, which appears to be realized by means of a reduced iodothyronine clearance and a lower sensitivity in TSH feedback.

Administration, Oral↗
PubMed1989

[Thyroid hormone anomalies in patients with insulin-dependent diabetes mellitus and circulating antithyroid microsomal antibodies].

In insulin-dependent diabetes mellitus (IDDM) several organ-specific autoantibodies are found in addition to pancreatic islet cell autoantibodies. In the present study we researched the presence of thyroid microsomal antibodies (anti-TMS) in 33 young patients with IDDM and evaluated contemporaneously their thyroid function. 5 patients (15.4%) are found with significant levels of circulating anti-TMS, among them 4 (12.1%) were also subclinical hypothyroid. However 6 other patients are found with mildly altered thyroid hormone pattern in absence of circulating anti-TMS. Basal and TRH-stimulated TSH were significantly higher, whereas serum FT4 was significantly lower, in patients with IDDM and circulating anti-TMS than in patients with IDDM but without anti-TMS. These observations indicate a significant incidence of mild or subclinical hypothyroidism in patients with IDDM and anti-TMS. Thus the screening for anti-TMS is recommended in all patients with IDDM, then thyroid hormone pattern of anti-TMS positive patients must be periodically followed.

Adolescent↗
PubMed1988

Bent helical structure in Trypanosoma lewisi minicircles.

By gel retardation assay and computational analysis we demonstrated a bent region in Trypanosoma lewisi, localized in two different classes of minicircles. We showed that in each minicircle this bent region is unique, adjacent to one of two highly conserved regions and characterized by adenine stretches. The same properties are conserved in the majority of minicircles from Trypanosomes tested so far. Therefore, we suggest that the genetic information could be located in a definite structure of minicircle DNA molecules rather than in the nucleotide sequence.

Adenine↗
PubMed1986

Platelet and coagulation functions during triphasic oestrogen-progestogen treatment.

The purpose of this investigation was the longitudinal evaluation of the hemostatic system before and after 1, 3, and 6 months of treatment with a triphasic oestrogen-progestogen combination. No changes of circulating platelet aggregates, as an index of in vivo platelet aggregability, and of megathrombocytes, an indirect evaluation of accelerated thrombocytopoiesis, were observed. A very slight, but significant, increase of Fibrinopeptide A (FPA), a reliable index of thrombin formation, was found only after 1 month of treatment; after 3 and 6 months, the increase of FPA was not homogeneous and not significant. Antithrombin III activity (AT III) showed no modifications after the first month; after 3 months AT III increased to a small extent, and after 6 months it was similar to basal values. Our findings indicate that the triphasic combination does not modify platelet functions and induces a low-degree activation of coagulation counteracted by an increased activity of the physiological inhibitors of blood clotting.

Adolescent↗
PubMed1986

Factors influencing platelet aggregation in whole blood.

In order to evaluate the interference of blood cells on platelet aggregation, spontaneous platelet aggregation (SPA), ADP, and collagen-induced platelet aggregation were investigated in whole blood by the impedance method and in platelet-rich plasma (PRP) by densitometric and impedance aggregometers. Stirring of the sample induced a significant decrease of neutrophils (P less than 0.001) but no changes of red blood cell (RBC) and platelet count. After collagen addition, a further decrease of neutrophils was observed, while RBC count was unmodified. The occurrence of SPA was not different in whole blood and in PRP. Platelet number and hematocrit did not affect either spontaneous or collagen-induced aggregation. A significant linear relation (r = -0.60, P less than 0.01) between neutrophil count and collagen whole blood platelet aggregation was found. Collagen- and ADP-induced aggregation were significantly higher and lower, respectively, in whole blood than in PRP using the densitometric method. No differences were observed in SPA and collagen platelet aggregation according to age and sex.

Adult↗
PubMedDate not supplied

Prospective study on thyroid function anomalies in severely ill patients.

Patients with severe non-thyroidal illness (NTI) often evidence concomitant anomalies in thyroid function (TF). In order to shed light on the implications of these anomalies and/or changes and disease course, we monitored TF changes in a selected cohort of 45 patients with serious NTI (21 with liver cirrhosis, 15 with renal failure and 9 with malignancy) from April 1985 to October 1989. TF test results on admission were as follows: all patients had normal thyroid stimulating hormone (TSH) levels; 16 patients had no TF abnormalities; 28 had decreased serum triiodothyronine (T3) and increased serum reverse triiodothyronine (rT3) levels, (8 of them had low serum free T3 values as well); 1 patient had subnormal level of both T3 and thyroxine (T4). Fifteen (53.5%) of the 28 subjects with initial low T3 sustained a subsequent decline in total and free serum T4 to subnormal levels; in 13 of these patients the drop occurred shortly before death. Patients in critical condition with below normal serum T4 also had decreased serum TSH concentrations: the so-called "low T3 and low T4 syndrome" might thus result from decreased TSH concentrations: due to failure of the usual feedback mechanism. Eighteen patients (40%) had died by the end of the study period. The mortality rate was 89% in patients with initial T3 level less than 0.40 nmol/L. This finding leads us to the hypothesis that initial low T3 levels in NTI patients are indicative of a poor prognosis.

Aged↗
PubMedDate not supplied

[Changes in blood levels of the pituitary-thyroid axis observed during therapy with protirelin ++ in hospitalized euthyroid patients with cerebrovascular disease].

The effects of a TRH-T (protireline tartrate) treatment at a dose of 2 mg/day for 3 weeks on the serum levels of the pituitary-thyroid axis hormones, have been studied in a randomized group of 10 elderly euthyroid hospitalized patients with cerebrovascular disease. At the end of the treatment an 8.3% mean increase of serum T3 level and a 12.5% mean increase of serum FT3 level (p less than 0.02 in both cases) have been observed. At the same time a 34% mean decrease of the basal TSH (p less than 0.05) and a 26% mean decrease of the delta-TSH after TRH-test (p less than 0.025) have been noted. However, the hormone concentrations changes never exceeded the normal values. In a randomized group of 9 hospitalized untreated patients with cerebrovascular disease used as controls (matched for age and sex), no significant changes of studied hormones have been recorded. In the treated patients, one week after the withdrawal of therapy serum levels of thyroid hormones and TSH went back to the levels observed before treatment. TRH-T seems to cause these modest hormone changes by decreasing the number of TRH receptors and the activity of TSH secreting cells. Nevertheless, the presence of the normal feedback in the pituitary-thyroid axis, allows a good tolerance to such a treatment.

Aged↗