Biomedical subjects

Y Agrawal

Publications and source records attributed to Y Agrawal.

9 recordsLinked to original sources

PubMed2006

The distribution of bone islands and juxta-articular bone cysts in the growing hand.

Bone islands and juxta-articular bone cysts are relatively common incidental findings when X-rays are taken for other purposes. We have identified that the incidence of bone islands in the hands of asymptomatic children between the ages of 5 and 13 years is 3.8% and the incidence of cysts in the same population is 2.8%. Bone islands were most common in the scaphoid, whilst juxta-articular bone cysts were most common in the capitate. The age at which they appear has not been reported previously. This study first identifies their presence in the hands of children of age 10 years and 2 months (bone islands) and 10 years 0 months (juxta-articular bone cysts). Most of the lesions were already present on the first radiograph taken. New bone islands appeared in five cases between the ages of 13 years and 1 month and 15 years and 3 months. New juxta-articular bone cysts were observed to appear in five cases between the ages of 10 years 10 months and 15 years 0 months. No island or cyst changed in size during the review period.

Adult↗

PubMed1987

Effect of secretory particles in bovine seminal vesicle secretion on sperm motility and acrosome reaction.

Particles found in bovine seminal vesicle secretion were enriched by centrifugation. They varied in size and morphology and contained Mg2+,Ca2+-activated ATPase, aminopeptidase A, alanyl aminopeptidase, gamma-glutamyl transpeptidase and dipeptidyl peptidase IV activities. Hyperactivation of sperm motility and the acrosome reaction were induced by these particles in epididymal spermatozoa suspended in a modified Ringer medium. The hyperactivation, analysed with a microscopic slide test, started within minutes of exposure to membrane particles and continued for 3-4 h, during which time spermatozoa underwent the acrosome reaction. Acrosome staining, phase-contrast microscopy and transmission electron microscopy revealed that the acrosome reaction started within 60 min at 37 degrees C and affected up to 80% of spermatozoa in 4 h. These membrane particles differed from those reported previously in other species in enzyme composition, function and organ of origin.

Acrosome↗

PubMed1986

Studies on the multiple forms of aminopeptidase A in bovine seminal vesicle secretion.

After gel filtration, anion exchange chromatography and chromatofocusing aminopeptidase A (AP-A) of bovine seminal vesicle secretion (VS-S) was found to exist in multiple forms. Depending on the pH used (pH 6.5-8.5) gel filtration of VS-S revealed 1-3 forms of AP-A. At pH 8.5 two dissimilar low-molecular-weight forms of AP-A converted into aggregated high-molecular-weight form. The aggregated AP-A was dissociated into an intermediate form with Triton X-100 and/or sodium deoxycholate and further into two low-molecular-weight forms with thiol compounds and neuraminidase. The aggregated, intermediate and low-molecular-weight forms of AP-A displayed some differences in catalytic properties, modifier characteristics and thermal inhibition.

Aminopeptidases↗

PubMed1986

Alanyl aminopeptidase of bovine seminal vesicle secretion.

Multiple forms of an aminopeptidase hydrolysing L-alanine- and various other amino acid-beta-naphthylamides in bovine seminal vesicle secretion were studied after fractionation on gel filtration, anion exchange chromatography and chromatofocusing. Two forms of the enzyme were found in all these fractionations: one with a high molecular weight was aggregated or particle-bound and the other had a molecular weight of about 237,000. The high-molecular-weight form dissociated with Triton X-100 via an intermediate into the basic enzyme form with concurrent change in the pI and anionic sites. The basic form of the enzyme differed from the high-molecular-weight forms in substrate preference, response to some modifiers, thermal stability and kinetic constants.

Alanine Transaminase↗

PubMed1986

Dipeptidyl peptidases in bovine reproductive organs and secretions.

Dipeptidyl peptidases (DPP) I-IV were analysed in homogenates of bovine reproductive organs as well as in seminal vesicle secretions and seminal plasma. The presence of various molecular forms of these enzymes was studied by fractionation using gel filtration, anion exchange chromatography and chromatofocusing. The eluting enzymes were pooled, and their biochemical properties were briefly characterized. The histochemical localization of DPP II and IV was carried out with the most active tissues. DPP I and III were absent from seminal plasma, but their highest activity was found in the epididymis and increased during sexual maturation. DPP II was found mainly in a single molecular form and displayed a wide distribution in the reproductive organs. Its activity in seminal plasma may be derived from various organs, although the major sources are probably the apical activity in the epididymis, ampulla and seminal vesicle. DPP IV activity was high in the cauda epididymis, and ampulla, and in the seminal vesicles and their secretions. The high activity of DPP IV in seminal plasma appeared to derive from these organs, which showed a strong apical reaction of the epithelial lining. In seminal vesicles the enzyme was mainly secreted attached to membrane particles called vesiculosomes.

Animals↗

PubMed1985

Variable distribution of aminopeptidase A in male reproductive organs of mammals.

Aminopeptidase A (AP-A) was analysed in the reproductive organs of the boar, bull, gerbil and man. High hydrolysis of alpha-L-glutamyl-beta-naphthylamide (GluNA) and alpha-L-aspartyl-beta-naphthylamide (AspNA) with activation by alkaline earth metals was detected in the ampulla, seminal vesicles, and seminal vesicle secretions of the bull and in the cauda epididymis of the boar and gerbil. In man, weak AP-A activity was found in all reproductive tissues. Histochemically, AP-A was localized in the epithelial cells of tissues having a high specific activity for the enzyme. AP-A was absent from human seminal fluid, whilst bovine seminal fluid had strong, and boar seminal fluid weaker, AP-A activity. Gel filtration of bull seminal vesicle secretions and seminal fluid, boar seminal fluid or an homogenate of boar and gerbil epididymal cauda and human epididymis and seminal vesicles on Sephacryl S-300 resulted in a major high-molecular-weight activity peak A at Ve/Vo = 1.17 and another low-molecular-weight peak B at Ve/Vo = 1.51 (man), 1.62 (boar, bull) or 1.75 (gerbil). This fractionation was not in all cases able to separate AP-A from aminopeptidase(s), which were active on L-alanine-beta-naphthylamide (AlaNA) but showed no activation by alkaline earth metals. Homogenates of bovine epididymis showed only the low-molecular-weight GluNA peak B, but two areas of activity for AlaNA hydrolysis. In bovine seminal vesicles and porcine epididymis, AP-A activity appeared to be linked with the functional maturity of these organs. The high-molecular-weight AP-A (peak A) appeared to be the predominant form in seminal fluid.

Aminopeptidases↗

PubMed1984

Aminopeptidase A in reproductive organs of the male rat: evidence for high activity in the posterior lobe of the prostate.

Of the reproductive organs of the male rat a high level of hydrolysis of alpha-L-glutamyl-beta-napthylamide (GluNA) and alpha-L-aspartyl-beta-naphthylamide (AspNA) in the presence of Ca2+ (5mM) (aminopeptidase A) was found in the posterior lobe of the prostate. Histochemically, this enzyme was localized in the epithelial cells of acini, which were grouped in the dorsal part and sharply separated from non-active acini in the anterior part of the lobe. A single peak of Ca2+-activated GluNA and AspNA hydrolysis was obtained after chromatofocusing at pI 4.9 and on anion exchange chromatography this activity eluted at 0.09 M NaCl. After gel filtration on Sepharose 6B a major peak of activity was found at the elution volume (Ve/Vo = 2.28). In all of these fractionation procedures aminopeptidase A was partially or totally overlapped by other aminopeptidases hydrolysing various amino acid-beta-naphthylamides. A pooled enzyme preparation gave an optimum at pH 7.3. The hydrolysis of GluNA was markedly enhanced in the presence of Ba2+, Ca2+ and Sr2+, but the hydrolysis of AspNA was activated only by Ca2+ and Sr2+. Castration caused a significant decrease in the hydrolysis of GluNA by the posterior lobe, but did not influence the low levels of activity in other parts of the prostate or in the seminal vesicles.

Amino Acids↗

PubMedDate not supplied

Electron microscopic study of the secretion process in bovine reproductive organs.

The origin and mechanism of the secretion of membrane-bound particles in bovine seminal plasma were studied with transmission (TEM) and scanning (SEM) electron microscopy of the epididymis, vas deferens, ampulla, and seminal vesicle of adult bulls. In the SEM study, all these organs were found to contain apical protrusions in the lining of the epithelial cells. Eventually the protrusions became detached and formed secretory bodies within the lumina of these organs. In the epididymis, the TEM study disclosed a granular and rather homogeneous content in the protrusions and bodies, whereas in the vas deferens they contained dilated cisternae of smooth endoplasmic reticulum. In the ampulla and seminal vesicle, the formation of the apical protrusions was associated with an accumulation of membrane-bound vesicles. These vesicles were found to be released from the storage bodies into the secretory fluid of the lumen. Both could be harvested from isolated seminal vesicle secretions by Percoll gradient centrifugation. It was concluded that various parts of the bovine reproductive organs discharge their secretory products at least partly by an apocrine mechanism. The membrane-bound particles in the seminal plasma, however, appear to be mainly derived from the ampulla and seminal vesicle.

Animals↗

PubMedDate not supplied

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Equipment and Supplies↗