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Biomedical subjects

A Villa

Publications and source records attributed to A Villa.

At least 199 records · Page 11Linked to original sources
PubMed1994

Short rib-polydactyly syndrome and pericentric inversion of chromosome 4.

We report on a newborn infant with clinical and radiological manifestations of some type of short rib-polydactyly syndrome who died soon after birth. Chromosomal studies on peripheral blood lymphocytes and chondrocytes demonstrated an apparently balanced pericentric inversion of chromosome 4 (present in the mother also). This association may have occurred by chance but, if not, the chromosomal breakpoints could interrupt the gene responsible for short rib-polydactyly syndromes, or else be related to the mechanism of short rib-polydactyly syndromes.

Abortion, Habitual↗
PubMed1994

The control of Ca2+ homeostasis: role of intracellular rapidly exchanging Ca2+ stores.

The role of rapidly exchanging intracellular Ca2+ stores in the control of Ca2+ homeostasis is reviewed. The following issues are discussed: the reasons why such stores exist in eukaryotic cells; the differences between the terminal cisternae of the skeletal muscle sarcoplasmic reticulum, which have direct, physical connection with the T tubules of the plasmalemma, and the Ca2+ stores located in the depth of the cytoplasm, which are stimulated by second messengers; the cytological nature (subcompartments of the ER) of the rapidly exchanging Ca2+ stores and their functional significance. The conclusions introduce recent developments in which intracellular Ca2+ stores have been investigated also by molecular biology techniques.

Animals↗
PubMed1994

Response to second-line weekly cisplatin chemotherapy in ovarian cancer previously treated with a cisplatin- or carboplatin-based regimen.

Response to a second-line weekly cisplatin chemotherapy in ovarian cancer previously treated with cisplatin- or carboplatin-based regimens was analysed in a clinical series observed between 1984 and 1991. Women who achieved pathological complete response or pathological optimal partial remission after first-line cisplatin- or carboplatin-based regimens were treated at recurrence or progression, occurring at least 4 months after first-line treatment, with second-line chemotherapy. A total of 72 women were included in the analysis. Second-line chemotherapy regimens were: cisplatin 1 mg/kg weekly for seven courses plus epirubicin 70 mg/m2 intravenously (i.v.) every 3 weeks for three courses (28 subjects), cisplatin 1 mg/kg plus etoposide 90 mg/m2 i.v. weekly for a total of seven courses (11 subjects) and cisplatin 1 mg/kg weekly for nine courses plus carboplatin 250 mg/m2 every 3 weeks for three courses (33 subjects). Of the 72 women, 22 (31%, 14 clinical, 8 pathological) had a complete response and 28 (39%), a partial response (24 clinical, 4 pathological). The 24-month cumulative survival probability was 63% in women with complete response, 32% in those who had partial response, but all the 22 non-responders died within 24 months from diagnosis of recurrence (log rank test P < 0.05). The frequency of complete response and partial response increased with the interval between first diagnosis and recurrence: among the 33 women who had recurrent disease to < 18 months from first diagnosis, complete response or partial response was obtained in 20 (61%) subjects, this figure was 67% (14 out of 21 women) among subjects who had recurrent disease between 18 and < 36 months from first diagnosis and 89% (16/18) among those who had recurrence > or = 36 months. In comparison with women who had recurrence 4- < 18 months from first diagnosis, the OR of response was 1.3 (95% CI 0.4-4.1) for those who had recurrence between 18 and < 36 and 5.2 (95% CI 1.1-24.3) for those who had recurrence > or = 36 months from surgery (chi 1(2) trend p < 0.05). Survival rate after the end of second line chemotherapy for women who relapsed 4- < 18 months, 18- < 36 or 36 months or more after surgery were, respectively, 24, 20 and 67% (log rank test, P < 0.05). Age at first diagnosis, histology, stage, and grading of the disease at first diagnosis and site of recurrence were not associated with response to second-line therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

The epidemiology of multiple pregnancies.

Over the last decades the frequency of multiple births has been on the decline in most developed countries. This trend, however, has been restricted to dizygotic twins, while monozygotic rates have remained stable or risen slowly. In more recent years, however, the fall in multiple dizygotic birth rates has ceased and a slight increase is observed. This trend and the increased frequency of triplets or higher-order births, registered from the early 1980s onwards, are essentially related to treatments for infertility. No single risk factor, such as maternal age, parity, oral contraceptive use, or declining fertility rates can explain the overall declining trends. In this paper we review the descriptive epidemiology and the main risk factors for multiple pregnancies.

Adult↗
PubMed1994

Defective expression of CD40 ligand on T cells causes "X-linked immunodeficiency with hyper-IgM (HIGM1)".

X-linked immunodeficiency with hyper-IgM (HIGM1) is a rare disorder, characterized by recurrent infections associated with very low or absent IgG and IgA, and normal to increased IgM serum levels. The disease has been earlier mapped to the q26-27 region of the X-chromosome. We have identified a novel molecule expressed on the surface of activated T cells, which was designated TRAP (Tumor necrosis factor Related Activation Protein), and could demonstrate that TRAP is a ligand for the CD40 receptor expressed on B cells. Our mapping of the TRAP gene to the Xq26.3-27.1 region suggested a causal relationship to HIGM1. Further work revealed that various mutations of the TRAP/CD40 ligand (CD40L) gene may lead to a defective expression of the TRAP/CD40L molecule on the T-cell surface in HIGM1 patients. A combination of structural and functional analyses finally demonstrated that the failure of TRAP/CD40L on T cells to interact with CD40 on B cells is responsible for the inefficient T-cell help for B cells observed in HIGM1. The observations made in HIGM1 allowed us to conclude that TRAP/CD40L is not required for IgM synthesis. In contrast, functional expression of TRAP is a prerequisite for effective immunoglobulin isotype switching and subsequent production of IgG, IgA and IgE by B cells in vivo. The interaction of TRAP/CD40L with CD40 thus provides a very critical link between the cellular and the humoral part of the immune system. The knowledge of TRAP/CD40L cDNA sequence, the availability of various reagents for the testing of expression and function of TRAP/CD40L, and our recent elucidation of the exon-intron structure of the TRAP/CD40L gene now provide all necessary tools for early diagnosis of affected patients and the detection of female carriers of HIGM1. The available information will also provide a basis for future attempts at gene therapy in this disease.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1994

Evolving pituitary hormone deficiency is associated with pituitary vasculopathy: dynamic MR study in children with hypopituitarism, diabetes insipidus, and Langerhans cell histiocytosis.

PURPOSE: To assess pituitary vascularization in children with hypopituitarism, central diabetes insipidus (DI), or Langerhans cell histiocytosis. MATERIALS AND METHODS: Dynamic MR images were obtained through the pituitary stalk after injection of gadopentetate dimeglumine in 21 patients (11 boys and 10 girls, aged 4-17 years) and 10 age-matched control subjects. RESULTS: Initial enhancement of the posterior pituitary lobe occurred simultaneously with that of the straight sinus in all subjects except four patients with central DI and a thick stalk. Enhancement of the entire anterior pituitary lobe was statistically significantly prolonged (P < .005) in the four patients with delayed initial posterior pituitary lobe enhancement. CONCLUSION: Fast-framing dynamic MR imaging provides new information on the blood supply of the hypothalamic pituitary area in normal and abnormal pituitary glands. Enhancement times exceeding 20 seconds for the posterior pituitary lobe and 30 seconds for the anterior pituitary lobe may suggest abnormal vascularization in the hypophyseal arteries and portal system.

Adolescent↗
PubMed1994

[Leukocyte procoagulant activity and chemotherapeutic agents: comparison between the effects of adriamycin and epiadriamycin on the procoagulant lympho/monocytic activity in vitro].

It is well known that a number of antineoplastic agents are able to induce procoagulant cellular activity and tissue factor not only in neoplastic cells but also in normal, monocyte/macrophage cells, and some of them, including adriamycin, even increase procoagulating activity of the factor already expressed, providing a further example of the possible co-participation of chemotherapy in the onset of thrombotic complication in cancer patient. Epirubicin is an analogue of adriamycin but differs strikingly in terms of its collateral effect, in particular being less cardiotoxic. To the authors' knowledge there are no data regarding the possible effect of epirubicin on lympho/monocyte procoagulant activity. This study shows that not only adriamycin but also epirubicin is able to increment the level of lympho/monocyte procoagulant activity "in vitro", with a dose-dependent effect, and to synergize with bacterial endotoxin in increasing this leukocyte activity, although the effect is significantly greater in the case of adriamycin. The importance of these findings at practical and clinical level remains to be defined, in particular in the length of the different pharmacokinetic behavior of these two chemotherapeutic agents and in the context of those neoplastic diseases for which adriamycin and Epirubicin treatment is most frequently used.

Blood Coagulation↗
PubMed1994

Laparoscopic treatment of ectopic pregnancy. Residents' learning experience.

Although operative laparoscopy is a safe and effective method of treating ectopic pregnancy, its widespread acceptance requires appropriate operator training and experience. This retrospective study correlated operative results with experience of the resident performing surgery. Thirteen postgraduate year 3 and 4 gynecology residents treated 60 ectopic pregnancies by laparoscopy. There were four complications: two cases of atelectasis and two of persistent human chorionic gonadotropin titers. There were no blood transfusions. We found that the duration of surgery decreased as operator experience increased, and residents who had experience with five or more cases required a mean operative time of 74 minutes. We conclude from our results that the minimal amount of supervised training necessary for gynecology residents to safety and expeditiously treat ectopic pregnancy laparoscopically is five cases. Furthermore, the minimal morbidity in this study supports our continued recommendation that each resident have prior training experience of at least 10 laparoscopic sterilizations before attempting his or her first case of ectopic pregnancy.

Clinical Competence↗
PubMed1994

Carbon monoxide-diffusing capacity in intravenous drug abusers: the effect of cigarette smoking and HIV infection.

A reduction in the Dco has been frequently found in intravenous drug addicts (IVDAs) and in subjects with HIV infection. Since also cigarette smoking decreases Dco, we studied a group of street IVDAs, who did not show respiratory symptoms and/or infiltrates on chest x-ray film. Sixty-two patients were presently smoking, 2 had never smoked. Twenty-seven were HIV-negative and 37 HIV-positive. Mean values for Dco (percent of predicted values) were 78 +/- 16.4 in HIV-positives compared to 97.9 +/- 17.6 in HIV-negatives (p < 0.0001) using smoking specific equations and 71.8 +/- 15.4 in HIV-positives compared to 80.7 +/- 13.4 (p < 0.0001) using non-smokers equations. Dco was < 80 percent in 19 of 35 (54.3%) HIV-positive subjects and in 4 of 26 (15.4%) HIV-negative subjects (p < 0.009) using predicted values for smokers, and in 28 of 35 (80%) HIV-positive subjects and in 6 of 26 (23.1%) HIV-negative subjects (p < 0.0001) using predicted values for non-smokers. These data suggest that Dco alterations observed in HIV-positive subjects are due, in absence of respiratory symptoms and/or chest x-ray abnormalities, to an interstitial pneumopathy due to HIV or to a subclinical pulmonary disease. We conclude that the knowing of smoking in IVDAs is useful, but the knowing of seropositivity is much more important, since a marked reduction of Dco in these subjects suggests an HIV-related lymphocytic alveolitis, an opportunistic infection or a malignancy.

Adolescent↗
PubMed1993

Structural features responsible for kinetic thermal stability of a carboxypeptidase from the archaebacterium Sulfolobus solfataricus.

Investigations were performed on the structural features responsible for kinetic thermal stability of a thermostable carboxypeptidase from the thermoacidophilic archaebacterium Sulfolobus solfataricus which had been purified previously and identified as a zinc metalloprotease [Colombo, D'Auria, Fusi, Zecca, Raia and Tortora (1992) Eur. J. Biochem. 206, 349-357]. Removal of Zn2+ by dialysis led to reversible activity loss, which was promptly restored by addition of 80 microM ZnCl2 to the assay mixture. For the first-order irreversible thermal inactivation the metal-depleted enzyme showed an activation energy value of 205.6 kJ.mol-1, which is considerably lower than that of the holoenzyme (494.4 kJ.mol-1). The values of activation free energies, enthalpies and entropies also dropped with metal removal. Thermal inactivation of the apoenzyme was very quick at 80 degrees C, whereas the holoenzyme was stable at the same temperature. These findings suggest a major stabilizing role for the bivalent cation. Chaotropic salts strongly destabilized the holoenzyme, showing that hydrophobic interactions are involved in maintaining the native conformation of the enzyme. However, the inactivation rate was also increased by sodium sulphate, acetate and chloride, which are not chaotropes, indicating that one or more salt bridges concur in stabilizing the active enzyme. Furthermore, at the extremes of the pH-stability curve, NaCl did not affect the inactivation rate, confirming the stabilizing role of intramolecular ionic bonds, as a pH-dependent decrease in stability is likely to occur from breaking of salt bridges involved in maintaining the native conformation of the protein.

Acetates↗
PubMed1993

Type 2 vasopressin receptor gene, the gene responsible nephrogenic diabetes insipidus, maps to Xq28 close to the LICAM gene.

Although long contigs have been assembled in Xq28, the interval between the anonymous probe St14 and the color vision locus is still incompletely defined. We report here that the recently cloned gene for type 2 vasopressin receptor (V2R) is physically linked to L1CAM using YACs and cosmids across about 180 kb of the region. Since it is known that L1CAM maps near the color pigment genes, this finding locates V2R in Xq28 in the area where nephrogenic diabetes insipidus (NDI) has been mapped by linkage analysis. The PFGE analysis of the clones positions V2R about 40 kb from the L1CAM gene in a region that appears to contain other unknown genes, since at least four putative CpG islands were identified by restriction analysis with rare cutter enzymes.

Animals↗
PubMed1993

Intracellular Ca2+ stores of rat cerebellum: heterogeneity within and distinction from endoplasmic reticulum.

Rat cerebellum microsomes were subfractionated on isopycnic linear sucrose (20-42%)-density gradients. The distribution of endoplasmic reticulum (ER) markers (RNA, signal-sequence receptor alpha, calnexin, calreticulin, the immunoglobulin-binding protein Bip) and markers of intracellular rapidly exchanging Ca2+ stores [Ca2+ channels sensitive to either Ins(1,4,5)P3 or ryanodine) was investigated biochemically and immunologically. The comparison indicates that: (a) vesicles bearing the InsP3 receptor were separated from those bearing the ryanodine receptor; (b) ER markers, i.e. Bip, calnexin, signal-sequence receptor alpha, RNA, did not sediment as either InsP3 or ryanodine receptors did; (c) calreticulin, an intralumenal low-affinity high-capacity Ca(2+)-binding protein, had a widespread distribution, similar to that of Bip and calnexin, and was present in Purkinje, granule, Golgi and stellate neurons, as indicated by immunofluorescent labelling of cerebellum cortex cryosections. The present results show that the ER is not a homogeneous entity, and that Ca2+ stores are heterogeneous insofar as InsP3 receptors and ryanodine receptors are segregated, either to discrete intracellular organelles or to specialized ER subcompartments.

Animals↗