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Biomedical subjects

M Marchini

Publications and source records attributed to M Marchini.

At least 55 records · Page 3Linked to original sources
PubMed1991

Negative staining and genesis of D-periodicity in native collagen fibrils.

An investigation was carried out on the mechanism which gives rise to the banding exhibited by collagen fibrils after negative staining. The negative staining (phosphotungstic acid) band patterns of native collagen fibrils (type I), isolated from calf reticular dermis, were compared with computer-drawn band patterns. The stimulations were based on the primary structure of bovine type I collagen, the "quarter stagger" molecular packing and different conformations of telopeptides. The results suggest that in negative staining, the stain exclusion effect depends on both spatial factors and water repelling factors being the "bulkiness" (molecular volume/length ratio) as well as the hydrophobicity of the amino acids of alpha 1 (I) and alpha 2 (I) chains directly involved. No final conclusion could be drawn about the contribution of positive staining to negative staining. Improvements in the simulations were achieved when the telopeptides were shaped according to particular conformational models.

Animals↗
PubMed1990

Electrophoretical patterns of seminal plasma proteins in patients with cystic fibrosis.

Seminal plasma (n = 12) from cystic fibrosis (CF) patients were analyzed by gel-electrophoresis using seminal plasma and expressed prostatic secretion from fertile men as controls. Heavy precipitation at the entering position of the gel and streaking in the gel matrix was observed, demonstrating a reduced solubility of seminal proteins in CF. Comparison of the protein patterns evidenced that CF-seminal plasma (CF-SP) mainly consisted of prostatic components. Although lactoferrin was undetectable in all samples, trace amounts of low molecular weight proteins were observed in two patients. This latter finding could imply that CF-SP may contain proteolytic fragments of prostatic and/or vesicular proteins or de novo synthesized components.

Adolescent↗
PubMed1990

Structural and ultrastructural defects in preovulatory endometrium of normo-ovulating infertile women with minimal or mild endometriosis.

To investigate whether a primary endometrial factor is involved in the pathogenesis of infertility in patients with minimal or mild endometriosis, we compared light, scanning, and transmission electron microscopic studies of preovulatory endometria of 15 endometriotic patients with 12 normal controls. All the women were infertile and normo-ovulating by standard criteria. Six morphometric indexes were considered. The scanning electron microscopic analysis revealed heterogeneity of the endometrial surface epithelium in 77% of the patients with endometriosis and in 16% of the controls. Glandular and stromal mitoses, basal vacuolated cells, and the ciliated:nonciliated cell ratio was significantly reduced in the endometriosis group compared with the controls. Further studies are needed to clarify the role of the observed endometrial anomalies in the pathogenesis of infertility associated with endometriosis.

Adult↗
PubMed1990

Susceptibility to HIV infection and AIDS in Italian haemophiliacs is HLA associated.

We compared the frequencies of HLA antigens in two matched groups of 31 HIV-seronegative and 31 HIV-seropositive haemophiliacs, exposed during the years 1981-85 to comparable amounts and batches of presumably infectious clotting factor concentrates. The frequency of A2 was significantly higher in HIV-seropositive than in seronegative haemophiliacs, with a relative risk (RR) of seroconversion of 3.92, whereas both Bw52 and DR4 were negatively associated with it. We also studied the distribution of HLA antigens in a larger group of 76 HIV-seropositive haemophiliacs, who were at different clinical stages of HIV infection (CDC classes II-IV) but were comparable for age and time elapsed since seroconversion. DR3 and DQw2 antigens were, particularly when concomitantly present, associated with a high risk of developing symptomatic HIV infection (RR = 11.79 and 25.33). Our data suggest that the HLA region controls susceptibility to infection with HIV and its progression to symptomatic disease in Italian haemophiliacs.

Adolescent↗
PubMed1990

Evaluation of histological and ultrastructural aspects of endometrium during treatment with gestrinone in women with amenorrhea or spotting.

Nineteen patients with a laparoscopic diagnosis of endometriosis were treated with gestrinone at a dosage of 2.5 mg twice a week for 6 months. In 7 who reported spotting in the first 3 months, the dose was increased to 2.5 mg three times a week during the second trimester. An endometrial sample was obtained from each patient at the time of laparoscopy (basal) and at 3 and 6 months of treatment. Endometrial structure and ultrastructure were studied. Areas of hemorrhage and of loss of surface epithelium and a lesser degree of involution of the surface epithelium were observed in the 3-month samples of 7 patients with spotting, compared with 12 with amenorrhea. It is hypothesized that incomplete endometrial involution could be due to differences in gestrinone pharmacokinetics in individual patients, in the quality and/or quantity of endometrial cytosolic receptors for sex steroids, or in endocrine compensation to administration of the drug.

Adult↗
PubMed1990

Endometrial patterns during danazol and buserelin therapy for endometriosis: comparative structural and ultrastructural study.

We studied endometrial structure and ultrastructure in serial biopsy specimens from patients with endometriosis treated with danazol (N = 19) or intranasal buserelin (N = 13) for 6 months. Biopsies were performed before and at 3 and 6 months of treatment. The specimens were studied by light, scanning, and transmission electron microscopy. Six morphometric indices were evaluated. Danazol produced a progestational effect on endometrial glands and stroma associated with marked hypotrophy of the mucosa, and buserelin treatment resulted in weakly proliferative or inactive mucosa. Both drugs induced noncyclicity and hypotrophy of endometrium although with different mechanisms of action, and it is suggested that they may have similar effects on ectopic endometrium. Because the atrophic effect of danazol appeared earlier than that of buserelin, the former could be recommended for short-term therapy.

Adult↗
PubMed1990

Endometrium of cavitary rudimentary horns in unicornuate uteri.

The rudimentary horns removed from ten patients with unicornuate uterus, subclass A1b, were studied by light and scanning electron microscopy. Seven of the horns removed were small in volume (range 7.5-15.7 mL) and three were larger (range 20.8-39.7 mL). In four cases the endometrial cavity communicated with the tubal lumen, hematometra was present in three cases, and endometriosis was diagnosed in six. In six of the seven rudimentary horns without hematometra, the endometrial mucosa did not correspond to the cycle phase of the endometrium of the hemiuterus; however, in the three rudimentary horns with hematometra, the endometrium presented cycle-phase characteristics similar to those of the hemiuterus. The endometrio-myometrial junction, the underlying myometrium, and the arcuate arterioles were always altered. We consider that the absence of cyclic changes in the endometria of the smaller horns may be attributed to reduced vascular supply, to the absence of any isthmocervical structure, and to the qualitative and/or quantitative differences in endometrial mucosal receptors.

Adolescent↗
PubMed1989

Dental elements in mature teratomas of the ovary: scanning electron microscope ultrastructure.

Seventy-two teeth from 10 ovarian mature teratomas and 12 unerupted and erupted teeth from subjects aged 8 to 21 years were examined at the scanning electron microscope to evaluate the morphologic and histogenetic differences. The ultrastructure of the teratomatous teeth was similar to that of the corresponding orthotopic tissues. Despite this similarity the morphology of the teratomatous teeth was much less well defined, attesting to the inductive effect of the contiguous tissues that are normally present in the oral cavity.

Adolescent↗
PubMed1989

Enhanced pre-ovulatory progesterone levels in fertile cycles during clomiphene citrate treatment.

We compared ovulatory changes in fertile and preceding infertile cycles in 21 patients with unexplained infertility conceiving after clomiphene citrate treatment. No significant differences were observed in follicular growth, cervical score and follicle stimulating hormone (FSH) levels. Progesterone was higher (P less than 0.05) in the 2 days preceding ovulation in fertile cycles, luteinizing hormone (LH) higher (P less than 0.05) the day before, and 17-beta-estradiol lower (P less than 0.05) 4 days before. Stimulating progesterone secretion by systematic LH administration before ovulation could improve secretory endometrial transformation and thus reproductive prognosis.

Adult↗
PubMed1989

Collagen fibril surface structures: freeze-etching data and computer modelling.

In order to investigate the correlation between primary structure and surface profile of collagen, freeze-fractured and deep-etched (dehydrated) collagen fibrils have been compared with a fibril model built directly from the amino acid sequence. The model appeared to be almost identical to the freeze-etched collagen fibril with respect to the most relevant features, such as the gap-overlap ratio and the location of the two main intraperiod ridges (X3 and X2). However, it did not show the minor ridges observed in the gap zone (X1 and Y1), thus suggesting that these structures, although consistently present in collagen fibrils, may in fact be due to post-translational modifications or to non-collagenic material adhering to the fibril.

Amino Acid Sequence↗
PubMed1989

Effect of peritoneal fluid on sperm motility and velocity distribution using objective measurements.

The aim of this study was to analyze in vitro the effect(s) of peritoneal fluid (PF) on sperm motility. Seventy PFs obtained during laparoscopy were tested on motile-rich sperm suspensions. Proportion of motile sperm and velocity distribution were evaluated by multiple-exposure photography technique. At time (t) = 0, PFs increased both sperm parameters as compared with control (P less than 0.01). Maximum effect was observed at t = 5 hours: 32 (45%) PFs increased and 5 (7%) decreased the proportion of motile sperm, while 8 (11%) PFs increased and 4 (6%) decreased sperm velocity. No correlation was found between a particular infertile group and a definite negative effect. However, 70% of PFs from fertile women maintained or increased the proportion of motile sperm at t = 5 hours, compared with 36% in the total infertile group. Comparison of the sperm motility effect(s) of a given PF on different ejaculates revealed that the effects observed also were influenced by the sperm sample tested. In conclusion, PFs can maintain or increase the motility of spermatozoa as function of time. However, some PFs can inhibit sperm motility and these effect(s) can be influenced by the sperm sample.

Body Fluids↗
PubMed1989

Enhanced preovulatory progesterone levels in clomiphene citrate-induced cycles.

We measured basal body temperature, cervical mucus, follicular diameter, and serum LH, FSH, 17 beta-estradiol, and progesterone daily in 40 spontaneous ovulatory cycles in 27 infertile women and in 40 clomiphene citrate-induced ovulatory cycles in 31 women. The cervical score was significantly lower and the serum FSH, LH, and 17 beta-estradiol levels were significantly higher during the follicular phase in induced compared with spontaneous cycles. Serum progesterone was significantly higher on the 3 days preceding ovulation and the day of ovulation in the induced cycles. These increased preovulatory serum progesterone levels could contribute to the lower cervical mucus score in the induced compared with spontaneous cycle, whereas their effect on the endometrium is still unclear.

Adult↗
PubMed1989

Recovery of Chlamydia trachomatis from the endometria of women with unexplained infertility.

Fifty-two women with unexplained infertility and 55 controls with recently proved fertility were screened for Chlamydia trachomatis (CT) infection in the blood and genital tract. Serum antibody titration was performed with indirect fluorescence. Cell cultures were performed to screen for CT in urethral and endocervical swabs, in endometrial samples taken without endocervical contamination and in salpingeal and/or peritoneal fluid samples. Anti-CT serum antibodies were detected in 36.5% of the patients; CT was isolated in urethral cultures in 26.9%, endocervical cultures in 23.1%, endometrial cultures in 25% and endosalpingeal and/or peritoneal fluid cultures in 1.9%. Comparison of the results in the patients and controls showed a significant difference in the incidence of CT infection in endometrial, urethral and endocervical cultures. Chlamydial endometritis could have been the direct cause of infertility in the patients studied or merely might have indicated endosalpingitis that was not detectable at laparoscopy.

Adult↗
PubMed1989

Endometrial reconstruction after hysteroscopic incisional metroplasty.

Endometrial reconstruction after hysteroscopic metroplasty of a septate uterus was studied by light microscopy and scanning electron microscopy when the uterus was removed 13 days after metroplasty for a histologic diagnosis of leiomyosarcoma. We observed a retraction of the margins of the incised septum, which could prevent the formation of intrauterine adhesions. Reepithelialization of the cut surface seemed to proceed both centripetally, by proliferation of the surrounding normal endometrium, and centrifugally from the bottom of the glands present at the base of the septum.

Adult↗
PubMed1988

Ultrastructure of endosalpingeal biopsies in infertile patients: correlation with reproductive success.

We calculated the percentage of ciliated cells (PCC) in salpingeal microbiopsies of 41 patients with tubal infertility and ampullary microbiopsies of 36 fertile women, using the planimetric method at 500-1000 x at the scanning electron microscope. No relation was found between PCC and fertility after surgery. Thus normal ciliation does not seem to be essential for reproductive success and other factors such as the state of preservation of the tubal wall may be important.

Biopsy↗
PubMed1988

Prediction and self-prediction of ovulation in clomiphene citrate-treated patients.

We studied 15 infertile patients for a total of 25 cycles in order to compare the predictive value of the following parameters in timing ovulation: basal body temperature (BBT), cervical mucus, serum E2 and LH, follicular growth as shown by ultrasonography, and urinary LH. The patients themselves tested urinary LH at home using Clearplan kits. BBT had low value as a predictive test for the time of ovulation, whereas ultrasonography had a predictive value of 9%, serum E2 50%, cervical mucus 59%, serum LH 63.6% and Clearplan kits 63.6%. The best predictive reliability in timing ovulation was obtained by considering both serum LH and E2 measurements. The Clearplan kits were as reliable as serum LH measurements and have greater practical advantages.

Adult↗