Biomedical subjects

B Baccetti

Publications and source records attributed to B Baccetti.

At least 55 records · Page 3Linked to original sources

PubMed1993

Evaluation of the antifertility activity of the broom Spartium junceum in the mammalian male.

Male adult rabbits and rats treated with Spartium junceum showed a significant decrease in fertility, demonstrated by a lower number of pregnancies. The target of the drug seems to be the acrosomal protease system, the activity of which appears greatly reduced, while the morphology of testicular cells and epididymal spermatozoa is only partially affected. The antifertility effect is completely reversible.

Acrosome↗

PubMed1993

Correlation between male fertility and acrosin-like protease activity in rats treated with Spartium junceum.

Intraperitoneal injections of extracts of Spartium junceum in adult male rats were shown to reduce the rate of fertility and acrosin enzyme activity. For the latter the drug effects could be divided into two phases: in the first stage a significant increase in proteolytic activity was observed in all experimental animals examined; and in the second stage, there was a general decrease of up to 50% in enzyme hydrolytic properties. There is a notable difficulty in correlating the acrosin activity and the data obtained from mating tests. The effect of drugs on the activity of another acrosomal protease, benzamidine-resistant protease, was assayed. A significant decrease in this enzyme was noted though the modality was different from that of acrosin. Extrapolating the data of the two co-extracted acrosomal proteases, the ratio of acrosin-like protease [E] and benzamidine-resistant protease [E]x, it was possible to correlate the value expressed to the rate of pregnancy. The implications of this finding is discussed although the exact molecular basis of the phenomenon is uncertain.

Acrosin↗

PubMed1993

Studies on varicocele. II. The inhibin secretion.

In this paper a previous interpretation given by the authors concerning one of the ways varicocele can affect fertility is confirmed. Moreover, it is definitely demonstrated that the high temperature stimulates inhibin secretion (and probably the testosterone-estradiol conversion) in the Sertoli cells, while the somatomedin secretion in vitro seems to be unaffected. It means that the action of the temperature on the germinal cells seems to be mediated by the pathway: inhibin (plus estradiol)-->pituitary-->FSH. Inhibin in the Golgi complex of Sertoli and germinal cells has been detected by electron microscopical immunocytochemical techniques.

Adult↗

PubMed1991

Spermatozoa and relationships in Palaeognath birds.

In this paper the authors describe the ultrastructure of the mature spermatozoon and the spermatid in Struthio camelus and Dromaius novaehollandiae. The first species is characterized by a rod-like perforatorium within an endonuclear canal in the anterior third of the nucleus, while the second is characterized by an extremely reduced completely extranuclear perforatorium. Other differences are in the sperm dimensions, the number of mitochondria and the length of the axonemal accessory fibers. Considering both the present data and previous findings, Palaeognath birds appear to be a peculiar and monophyletic group, characterized by: 1), a conical acrosome surrounding the nucleus; 2), a fibrous sheath around most of the axoneme; and 3), an elongated distal centriole occupying the entire midpiece. Within this group, Tinamiformes seem to be more primitive than Struthioniformes. In the latter order Dromaius is distinctly different from the reduced Struthio and Rhea which are closely related to one another by the presence of a rod-like endonuclear perforatorium.

Animals↗

PubMed1991

Studies on varicocele. 1. Submicroscopical and endocrinological features.

In this study we have selected a group of patients affected by a more or less severe condition of varicocele. After the evaluation of spermatogenesis and sperm function by electron microscopy we have demonstrated that the sperm malformations are mostly due to immaturity. Subsequently we have observed low FSH levels in the blood, concomitant with inhibin high contents, and we have studied Sertoli cells at submicroscopical level. In conclusion we suggest the following mode of action of varicocele in endocrinologically and spermatologically altered patients: varicocele----Sertoli cells----increased inhibin----hypophysis----decreased FSH----decreased testosterone----aberrant spermatogenesis----immature spermatozoa. The research will continue.

Adult↗

PubMed1991

HIV particles detected in spermatozoa of patients with AIDS.

In this paper the Authors describe the presence of HIV particles on and in mature spermatozoa either ejaculated by AIDS patients or incubated in vitro with HIV. Both kinds of spermatozoa have particles localized around the sperm organelles. In the first case, the nucleoid of the virus can be enveloped by a membrane-like coat or be devoid of it and form buddings in the plasma membrane. In the in vitro infected spermatozoa, only membrane enveloped nucleoids are present, and no process of budding can be found. The Authors conclude considering that the spermatozoa of the AIDS patients can be penetrated by the virus particles in different moments of their life, and show the HIV particles in different stages of their cycle: some of them have freshly penetrated the sperm, and are still contained in a membrane-like coat, others are replicated and are budding through the sperm plasma membrane. On the contrary, in vitro infected spermatozoa have only freshly penetrated virus particles, and lack buddings and membrane-free nucleoids. The presence of the HIV virus in spermatozoa is substantiated by labelling with monoclonal or polyclonal anti-HIV antibodies.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Specific localization of lectins in boar and bull spermatozoa.

The roles that complex carbohydrates play in gamete recognition and fertilization are well-documented. This study was designed to identify and map sites of N-linked oligosaccharides in boar and bull sperm. Plant lectins, conjugated with FITC, RITC and gold particles, were used as probes for specific sugar moieties in sperm membranes. Results showed strong labeling of sperm heads by most lectins. However, lectins with specificities for mannosyl, glucosyl, and sialic acid were predominantly distributed over the sperm acrosomal region. Lectins specific for fucosyl residues predominantly stained the postacrosomal regions of both boar and bull sperm. Lectin gold studies revealed that mannosyl and galactosyl-linked residues occupied the acrosomal membrane and plasma membrane in the postacrosomal region, but not the nucleus or nuclear membrane. The cytoplasmic droplet, middle piece and flagellum of boar and bull sperm were moderately stained by lectins. The microquantitative analysis confirmed the fluorescence data. The presence of fucosyl residues predominantly in the postacrosomal regions lends credence to the suggestion that glycoproteins rich in fucosyl-like residues may be a universal carbohydrate moiety involved in recognition processes in mammalian fertilization.

Animals↗

PubMed1989

Crater defect in human spermatozoa.

This report describes the "crater defect" in human spermatozoa, a malformation that consists of a nuclear and acrosomal invagination present in 100% of the cells, whereas tail structure and motility are fairly normal. The defect occurs during spermiogenesis. A possible concomitance with abnormalities in the microtubular apparatus involved in the sperm molding is discussed.

Adult↗

PubMed1989

Morphogenesis of the decapitated and decaudated sperm defect in two brothers.

The "decapitated sperm" defect, found in both of two sterile brothers, may be assumed to have a genetic origin. The present material suggests that the term "decapitated spermatozoa" is not exact, because detached heads and tails were found in the brothers' ejaculate that could be regarded as "decapitated tails" and "decaudated heads." The present report describes frequent, more or less advanced stages of detachment. Both heads and tails showed a normal structure in which only the postnuclear region was deficient, lacking basal plate and implantation fossa. A break at a different level of the midpiece, and therefore three kinds of separation, were observed. The defect, according to the present research, must originate in the testicular region, whereas the detachment occurs in the epididymis.

Adult↗

PubMed1989

Localization of acrosomal enzymes in Arthropoda, Echinodermata and Vertebrata.

The presence and localization of acrosin and hyaluronidase have been detected by immunocytochemistry in animals belonging to different phyla and characterized by the different structure of the acrosomal complex. Acrosin is widely distributed from Insecta to Echinodermata and Vertebrata; hyaluronidase has a similar diffusion, but seems to be absent from an Insect and from Echinodermata. The presence of extraacrosomal layer and perforatorium seems not to be related to that of the two enzymes, that are absent from Teleost species devoid of acrosome or having only a pseudoacrosome.

Acrosin↗

PubMed1989

Bidirectional swimming in spermatozoa of Tephritid flies.

Our observations show that spermatozoa of the Mediterranean fruit fly Ceratitis capitata and of Dacus oleae and Dacus dorsalis are capable of swimming backwards as well as forwards, and that they can change direction abruptly. The preferred direction is backwards, observed in spermatozoa obtained from the male genitalia. Forwards swimming spermatozoa were frequently seen in the spermatheca and close to the eggs. The change in swimming direction appears to be effected solely by a change in the direction of bend propagation, with no significant change in other waveform parameters. In vitro reactivated spermatozoa swim forwards only and require a minimum free Ca++ concentration of about 10(-6) M for movement. A switching of wave propagation from one direction to the other under control of intracellular free Ca++ concentration is suggested. Perhaps the backwards movement allows easier delivery of spermatozoa from the common envelope embedding the heads in the male apparatus, and assures a more efficient movement of the sperm towards the egg, especially given the enormous relative length of the head. The forwards movement is favoured in order to orient the sperm for penetration of the micropile.

Animals↗

PubMed1988

Immunocytochemistry and sperm pathology.

In this paper the Authors describe the localization of some significative proteins (acrosin, actin, tubulin, vimentin) detected by immunocytochemical methods in human infertile spermatozoa and correlate their distribution with the ultrastructural characteristics of the same spermatozoa, in order to clarify the structural bases of infertility.

Acrosome↗

PubMed1987

Action of gossypol on rat germinal cells. II. The acrosome.

The action of gossypol on the acrosomal complex in rats has been investigated by microscopical and submicroscopical methods. The drug displays its morphological action only on spermatozoa during the transit through the epididymis, causing malformations and vesiculations. It appears to exert a primary action on the S-S groups formation, disturbing morphological molding occurring in this period and inhibiting capacitation.

Acrosome↗

PubMed1986

Evolutionary trends in sperm structure.

In the marine invertebrates which practise external fertilization, the spermatozoon is a flagellate cell, possessing an acrosomal complex made up of acrosome and perforatorium. In the animal phyla which adapted to land after having achieved internal fertilization the spermatozoon has acquired an elongated shape and develops accessory cytoskeletal organelles in the tail. In the highest forms, the flagellum seems to have become too long for perfect motility; in such a condition, aberrant axonemal patterns can appear and aflagellate spermatozoa can also be found. At the apex of the terrestrial phyla, alternative motile apparatuses have been achieved and also the acrosomal complex varies, according to the different structures of egg envelopes.

Animals↗

PubMed1985

Live and reactivated motility in the 9+0 flagellum of Anguilla sperm.

The sperm flagella of the eel, Anguilla anguilla, are capable of vigorous motion in spite of having an axoneme with reduced structure that lacks the outer dynein arms, radial spokes and spoke heads, the two central tubules and the central tubule projections that are all part of the standard "9+2" axoneme. These sperm progress forward rapidly as a result of the propagation of helicoidal waves distally along the flagellum. Their flagellar beat frequencies are high, 93 Hz at 21 degrees C, and they roll at a frequency of about 19 Hz. Eel sperm could be demembranated with Nonidet P-40 and reactivated with MgATP2- in 0.22 M K acetate at pH 8.1. The reactivated motility closely resembles that of the live sperm, with a beat frequency of 69 Hz, but the demembranated flagella are unusually fragile, and commonly disintegrate by a combination of splitting, coiling, and sliding within a few minutes. Little reactivation is obtained if acetate is replaced by Cl- in the reactivating medium. The Michaelis constant for beat frequency (0.2 mM) is similar to that obtained for several "9+2" flagella. These sperm, however, appear to lack the mechanism by which Ca2+ regulates waveform. Our results indicate that eel sperm flagella, which at rest are straight, are induced to bend helicoidally by ATP, as the result of sliding between tubules that is blocked at both the base and tip of the organelle. The flagellar waveform consists of a series of planar bends separated by short regions of right-handed twist, which give it an overall left-handed helicoidal form.

Anguilla↗

PubMed1985

High voltage electron microscopy of sperm axoneme.

The axoneme of sea urchin spermatozoon has been examined in whole preparation by high voltage electron microscopy. Radial spokes appear arranged in triplets with intratriplet distance of 40 nm, distance between spoke 1 and 2 of 32 nm and between spoke 2 and 3 of 24 nm. Spoke 1 is thicker than others; the complex of the triplets around the 9 microtubule doublets forms a helix of 96 nm pitch. Nexin links connect the A tubule of a doublet with the B of the adjacent one, and also form a helix of 96 nm pitch.

Animals↗

PubMed1984

Morphogenesis of 'decapitated' spermatozoa in a man.

Study of biopsy specimens of a man with 'decapitated' spermatozoa indicated that the malformation was due to an overproduction of a membraneous vesicles system by the Golgi complex in the region between the centrioles and acrosome during the spermatid stage. The tails were almost normal in structure and 50% were motile in the ejaculate although few followed a straight trajectory.

Adult↗

PubMed1984

Sperm morphogenesis, structure and function in humans over 70 years old.

Semen and testicular biopsy samples from different aged human donors have been examined for any age related changes in sperm morphogenesis, structure and function. Various abnormalities and defects, some being unique to spermatozoon of elderly men, were observed at the light and electron microscope levels. In spite of this, the best fractions of ejaculated spermatozoa population maintains his function, as demonstrated by some complete egg penetrations observed with the 'zona free' hamster egg test system.

Acrosome↗