Search PubMed⌕ Search

Biomedical subjects

A Agarwal

Publications and source records attributed to A Agarwal.

At least 289 records · Page 16Linked to original sources
PubMed1996

Optimal dose and duration of exposure to artificial stimulants in cryopreserved human spermatozoa.

PURPOSE: Poor sperm motility after cryopreservation is associated with infertility. For any pharmacological stimulation to be of clinical value, its effect in enhancing motility and other motion characteristics should be maintained for at least 1 hour. MATERIALS AND METHODS: Three motility stimulants (pentoxifylline, caffeine and 2-deoxyadenosine) were incubated with post-thaw semen samples from 11 healthy donors for 0, 30, 60, 120 and 180 minutes. The final concentrations used were 2.5 mM., 5 mM. and 10 mM. for pentoxifylline; 1 mM., 2 mM. and 5 mM. for caffeine, and 0.5 mM., 1 mM. and 2.5 mM. for 2-deoxyadenosine. Percent motility and changes in motion characteristics were measured on a computer assisted semen analyzer. RESULTS: Compared to controls (0 minutes, no stimulant), an immediate increase in motility and other motion parameters was noted with all 3 stimulants. All stimulants caused a significant increase in percentage motility at all periods studied (p < 0.01). Similarly, pentoxifylline increased other motion parameters at the 2.5 mM. concentration (p < 0.01), caffeine was effective in increasing curvilinear velocity, average path velocity and amplitude of lateral head displacement (p < 0.01) at 5 mM., and 1 and 2.5 mM. of 2-deoxyadenosine increased the curvilinear velocity, straight line velocity, average path velocity and amplitude of lateral head displacement (p < 0.01). Among all stimulants only 2-deoxyadenosine increased linearity only at the 1 mM. concentration. CONCLUSIONS: Our study suggests that these stimulants, when used at optimum concentrations, can maintain the improved sperm quality for durations longer than the minimum needed for fertilization. This finding may be significant in improving the poor semen quality observed after cryopreservation in oligospermic samples and in semen specimens from cancer patients.

Caffeine↗
PubMed1996

Differential expression of elastin and alpha 1(I) collagen mRNA in mice with bleomycin-induced pulmonary fibrosis.

Interstitial pulmonary fibrosis is characterized by increased production of connective tissue components, including collagen and elastin. The role of elastin turnover in pulmonary fibrosis is not clear, and it is not known whether elastin and collagen are regulated separately or together during the inflammatory process. Mice with bleomycin-induced pulmonary fibrosis were investigated to determine the temporal and spatial changes in localization of elastin mRNA expression, as well as to compare elastin mRNA expression with that of alpha 1(I) collagen mRNA expression. In control (saline-treated) lungs, elastin mRNA was detected by in situ hybridization in arterial walls. No signal was found in alveolar or airway walls or in pleura; alpha 1(I) collagen mRNA was detected in the tissue underlying the airway epithelium. An increase in elastin mRNA expression in muscular arteries was observed 3 days after bleomycin instillation. Expression was also seen in the adventitia of terminal airways and adjacent small blood vessels. Expression of alpha 1(I) collagen mRNA increased in the tissue underlying the airway epithelium. In the pleura, alpha 1(I) collagen mRNA expression was found, although no pleural thickening was evident. The alpha 1(I) collagen mRNA expression was particularly increased in the adventitia of terminal airways and in associated small blood vessels. Obvious in areas of fibrosis, elastin mRNA expression was occasionally increased in the pleura and airway wall 7 days after bleomycin treatment; alpha 1(I) collagen mRNA expression was generally stronger than elastin mRNA expression in areas of fibrosis and was frequently intense in the adventitia of airways and associated blood vessels. The fibrotic areas showed increased elastin mRNA expression 14 and 30 days after bleomycin treatment. The arteries in fibrotic areas showed normal elastin mRNA levels. In the areas of fibrosis and in the adventitia of airways and adjacent blood vessels, alpha 1(I) collagen mRNA expression was very high. In conclusion, lung elastin biosynthesis is markedly altered by bleomycin treatment. The localization and intensity of elastin mRNA expression is different from the expression of alpha 1(I) collagen mRNA.

Animals↗
PubMed1996

Value of clinical diagnosis in predicting the quality of cryopreserved sperm from cancer patients.

PURPOSE: Cryopreservation of semen from patients with malignant diseases (primarily testicular cancer, Hodgkin's disease and lymphoma) before specific chemotherapy, radiation or surgical therapy has become a realistic option to preserve fertility. Nevertheless, the post-thaw sperm quality in these patients is poor. Whether the clinical diagnosis of malignancy affects the cryopreservation of human sperm is unknown. Such an association could allow post-thaw sperm quality to be predicted. MATERIALS AND METHODS: We compared the effect of cryopreservation on sperm motility, velocity, linearity, amplitude of lateral head movement, motility index and motile sperm count in specimens from 30 normal men, 34 with testicular cancer, 39 with Hodgkin's disease, and 19 with leukemia and lymphoma who were referred for sperm banking during a 5-year period. RESULTS: The pre-freeze and post-thaw motility, motility index and motile sperm count were significantly lower in patients than in normal men (p < 0.01). No significant differences were noted among the patient groups. Similarly, no significant differences were noted after cryopreservation. Our results indicate that the poor pre-freeze sperm quality in some patients with malignancies explains the poor post-thaw results. However, the deterioration in sperm function after cryopreservation of semen among patients with different malignancies and normal donors appears to be similar. CONCLUSIONS: Clinical diagnosis of malignancy is not an adequate predictor of the effect of cryopreservation on human semen.

Cryopreservation↗
PubMed1996

Sperm quality improvement in cryopreserved human semen.

PURPOSE: We determined if separation of spermatozoa (washed) on a discontinuous colloidal suspension of silica (Percoll) density gradient before cryopreservation improves post-thaw motility compared to an unprocessed (raw) cryopreserved sample. MATERIALS AND METHODS: Ten normal healthy volunteers recruited into the andrology laboratory donor program were studied. Raw and washed cryopreserved spermatozoa were compared for loss of motility with time, motion characteristics, viability and membrane integrity after incubation for 1, 6 and 24 hours. Within group comparisons were made to baseline measurements (0 hours before incubation). RESULTS: Raw and washed cryopreserved spermatozoa showed statistically significant decreases in motility and other motion characteristics after thawing. There were significant decreases in motility and other motion characteristics after incubation periods of 1, 6 and 24 hours, and significant decreases in viability and membrane integrity at 6 and 24 hours in the unprocessed spermatozoa. Although, motility and motion characteristics of washed samples decreased significantly with longer incubation periods, loss of motility with time (longevity) was greater in raw samples. Washed samples retained greater sperm motility for up to 24 hours (p < 0.03). CONCLUSIONS: Specimens prepared by Percoll separation techniques before freezing offer the possibility of selecting spermatozoa that retain motility for up to 24 hours. This finding can be of benefit for couples undergoing intrauterine insemination to achieve pregnancy.

Cell Survival↗
PubMed1996

Suitability of the hypo-osmotic swelling test for assessing the viability of cryopreserved sperm.

OBJECTIVE: To determine whether the hypo-osmotic swelling test can assess viability of frozen spermatozoa. DESIGN: Fresh semen specimens were divided into two aliquots: one was not processed and the other was processed by swim-up. Both aliquots were then cryopreserved by the liquid nitrogen vapor method. SETTING: Andrology laboratory at a tertiary care facility. PATIENT(S): Eleven volunteers with proven fertility. INTERVENTION(S): The hypo-osmotic swelling test and the sperm viability assessment by Hoechst 33258 (Sigma Chemical Co., St. Louis, MO) and eosin-nigrosin strains were performed in each aliquot. MAIN OUTCOME MEASURE(S): The results of hypo-osmotic swelling test as indicated by swelling of sperm tails were compared with the viability results obtained by Hoechst 33258 stain before freezing and by Hoechst-33258 and eosin-nigrosin stains after freezing. RESULT(S): The hypo-osmotic swelling test and Hoechst 33258 viability results were correlated highly in unprocessed and processed fresh specimens (r = 0.95). After cryopreservation, there was no correlation between hypo-osmotic swelling test and Hoechst 33258 or between hypo-osmotic swelling test and eosin-nigrosin. Prefreeze sperm processing did not influence the post-thaw results. Viability assessed by Hoechst 33258 and eosin-nigrosin was well correlated (r = 0.72). CONCLUSION(S): The hypo-osmotic swelling test can accurately evaluate viability in fresh human spermatozoa but not in cryopreserved ones. Thus, this test cannot be used to select viable cells in cryopreserved samples for assisted reproductive procedures, such as intracytoplasmic sperm injection.

Aniline Compounds↗
PubMed1996

Current trends in the diagnosis and management of cystic hydatid disease of the liver.

Cystic hydatid disease caused by Echinococcus granulosus most commonly involves the liver. Recent years have seen many changes in modalities of diagnosis and treatment of cystic disease in the liver. Currently used methods of immunodiagnosis, newer radiological modes of imaging, emerging non-surgical techniques of management and the impact of minimal access surgery in this disease are highlighted in the present review.

Animals↗
PubMed1995

Novel non-nucleoside inhibitors of human immunodeficiency virus type 1 reverse transcriptase. 5. 4-Substituted and 2,4-disubstituted analogs of nevirapine.

Molecular modeling analysis of the recently published X-ray crystal structure of nevirapine bound to wild type human immunodeficiency virus type 1 reverse transcriptase (WT-RT) indicated the presence of a lipophilic cavity proximal to the 4-position of the inhibitor. A series of 4-substituted derivatives of nevirapine were thus synthesized to assess structure-activity relationships (SARs) and to see if increased binding to this region might translate into greater activity against mutant RTs. The results show that compounds with an appropriately spaced aryl ring appended to the 4-position of the dipyridodiazepinone ring system show good activity against WT-RT. Furthermore certain derivatives appear to inhibit the Y181C mutant RT. Attempts to combine these results with the recent discovery that 2-substituents enhance activity against the Y181C mutant led to a few compounds with moderate activity against both enzymes. The SAR of these two positions, however, could not be combined in a simple fashion.

HIV-1↗
PubMed1995

Role of aromatic residues in stabilization of the [Fe4S4] cluster in high-potential iron proteins (HiPIPs): physical characterization and stability studies of Tyr-19 mutants of Chromatium vinosum HiPIP.

The functional role of residue Tyr-19 of Chromatium vinosum HiPIP has been evaluated by site-directed mutagenesis experiments. The stability of the [Fe4S4] cluster prosthetic center is sensitive to side-chain replacements. Polar residues result in significant instability, while nonpolar residues (especially with aromatic side chains) maintain cluster stability. Two-dimensional NMR data of native and mutant HiPIPs are consistent with a model where Tyr-19 serves to preserve the structural rigidity of the polypeptide backbone, thereby maintaining a hydrophobic barrier for exclusion of water from the cluster cavity. Solvent accessibility results in more facile oxidation of the cluster by atmospheric oxygen, with subsequent rapid hydrolysis of the [Fe4S4]3+ core.

Aerobiosis↗
PubMed1995

p53 controls both the G2/M and the G1 cell cycle checkpoints and mediates reversible growth arrest in human fibroblasts.

Increased expression of wild-type p53 in response to DNA damage arrests cells late in the G1 stage of the cell cycle by stimulating the synthesis of inhibitors of cyclin-dependent kinases, such as p21/WAF1. To study the effects of p53 without the complication of DNA damage, we used tetracycline to regulate its expression in MDAH041 human fibroblasts that lack endogenous p53. When p53 is expressed at a level comparable to that induced by DNA damage in other cells, most MDAH041 cells arrested in G1, but a significant fraction also arrested in G2/M. Cells released from a mimosine block early in S phase stopped predominantly in G2/M in the presence of p53, confirming that p53 can mediate arrest at this stage, as well as in G1. In these cells, there was appreciable induction of p21/WAF1. MDAH041 cells arrested by tetracycline-regulated p53 for as long as 20 days resumed growth when the p53 level was lowered, in striking contrast to the irreversible arrest mediated by DNA damage. Therefore, irreversible arrest must involve processes other than or in addition to the interaction of p53-induced p21/WAF1 with G1 and G2 cyclin-dependent kinases.

Cell Cycle↗
PubMed1995

Simultaneous overexpression of copper- and zinc-containing superoxide dismutase and catalase retards age-related oxidative damage and increases metabolic potential in Drosophila melanogaster.

The objective of this study was to elucidate the nature of the mechanisms by which overexpression of copper- and zinc-containing superoxide dismutase (Cu,Zn-SOD) and catalase extends life span of Drosophila melanogaster. Experimental flies containing single extra doses of Drosophila Cu,Zn-SOD and catalase genes were compared with appropriate controls at different ages. Overexpression of Cu,Zn-SOD and catalase caused a retardation in the accumulation of 8-hydroxydeoxyguanosine during aging and in response to the exposure of live flies to x-rays. The age-related loss of glucose-6-phosphate dehydrogenase activity (Glu-6-P dehydrogenase) and the increase in the rate of mitochondrial H2O2 generation were less steep in the experimental than control flies. The rate of in vivo oxygen consumption in the latter two-thirds of life span was higher in the experimental than in the control flies. Furthermore, the metabolic potential, or the total amount of oxygen consumed during an average life span, was about 30% greater in the experimental than the control flies. Altogether, results of this study indicate that overexpression of Cu,Zn-SOD and catalase ameliorates the age-related accumulation of molecular oxidative damage and susceptibility to such damage in response to acute oxidative stress while prolonging the metabolic life of flies. The concept that oxidative stress is a causal factor in the aging process is supported.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1995

Cryopreservation and semen quality in patients with Hodgkin's disease.

BACKGROUND: Cryopreservation of semen from patients with Hodgkin's disease yields fewer motile sperm than from fertile men without Hodgkin's disease. However, although poor sperm quality and subfertility have been associated with Hodgkin's disease, whether the disease adversely affects sperm quality is not clear because many studies evaluated semen quality after chemotherapy or radiation therapy had begun. Furthermore, the effect of cryopreservation on semen quality in these patients is unknown. This study investigated pretreatment sperm quality and the effect of cryopreservation on semen quality in patients with Hodgkin's disease. METHODS: Specimens from 39 patients with Hodgkin's disease and 30 normal volunteers who underwent sperm banking over a 5-year period were analyzed. No patient had undergone chemotherapy or radiation therapy before sperm banking. The nitrogen vapor technique, using Test-Yolk buffer with glycerol as a cryoprotective agent, was used for cryopreservation. Prefreeze and postthaw motile sperm count (MSC) and motion characteristics, namely motility, curvilinear velocity (VCL), linearity, amplitude of lateral head movement (ALH), and motility index, were compared between the two groups. RESULTS: Prefreeze values for MSC (P = 0.0001), motility (P = 0.0001), motility index (P = 0.0001), and VCL (P = 0.0019) differed significantly between patients and donors. Except for linearity and ALH, postthaw sperm MSC, motility, VCL, and motility index decreased significantly (P = 0.0001) in both groups. However, the percentage decline in semen quality from prefreeze to postthaw values did not differ significantly between donors and patients. CONCLUSION: The pretreatment semen quality in patients with Hodgkin's disease is poor compared with that of normal fertile men. However, half the patients had a normal MSC, so a clinical diagnosis of Hodgkin's disease does not predict cryopreservation outcome adequately. Semen cryopreservation should be encouraged as a routine part of the therapeutic management of men of reproductive age who will undergo chemotherapy or radiation therapy for Hodgkin's disease.

Adolescent↗
PubMed1995

Identification of the major tyrosine kinase substrate in signaling complexes formed after engagement of Fc gamma receptors.

We have recently identified the protein product of the c-cbl proto-oncogene as an SH3 binding protein expressed in macrophages. To investigate the possibility that p120c-cbl is involved in signaling pathways initiated by cell surface receptors for IgG (Fc gamma R), lysates of HL60 cells were examined for tyrosine phosphorylation of p120c-cbl upon Fc gamma R engagement. Our findings demonstrate that p120c-cbl is tyrosine-phosphorylated upon Fc gamma R engagement and that this molecule represents the major tyrosine kinase substrate in this signaling pathway. Protein complexes containing p120c-cbl, p72syk, and p56lyn were observed either in resting or activated cells. In vitro studies showed that the direct association between p120c-cbl and p56lyn was mediated by the SH3 domain of p56lyn.

Enzyme Precursors↗
PubMed1995

A case of cutaneous phaeohyphomycosis caused by Exserohilum rostratum, its in vitro sensitivity and review of literature.

A 40 year old woman presented with the infection of skin of 3 years duration on the upper anterior aspect of fore-arm. Histologic examination of the skin tissue revealed dematiaceous hyphae, aggregated structures or single celled elements. On detailed mycological examination the isolate was identified as Exserohilum rostratum. Among the antimycotic tested in vitro amorolfine was found to be most effective with MIC value of 3 mcg/ml. This is the first report of E. rostratum infection of man from India.

Adult↗
PubMed1995

Positive myeloperoxidase staining (Endtz test) as an indicator of excessive reactive oxygen species formation in semen.

PURPOSE: Although the significance of leukocytospermia in semen remains controversial, evidence exists that white blood cells (WBCs) may adversely affect sperm function and act as a potential cofactor in male infertility. Nevertheless, the mechanisms by which leukocytes may alter sperm function in vitro is unknown. Recent investigations suggest that reactive oxygen species (ROS) generated by the polymorphonuclear (PMN) granulocytes could adversely affect sperm function. The objective of this study was to investigate the relationship between the presence of leukocytospermia as determined by the Endtz test and the excessive formation of ROS. METHODS: The WBC concentration and ROS formation in human semen, obtained from men consulting for infertility, were assessed and compared to that of normal donors. ROS was measured by a chemiluminescence assay using luminol and a Berthold luminometer. The WBC concentration was determined with a myeloperoxidase staining technique (Endtz test). Specimens were obtained from 94 subjects (20 donors, 74 patients). RESULTS: Of the 20 donors, 2 were Endtz positive and ROS positive; 18 were Endtz negative with 2 (11%) ROS positive. In the patient group (n = 74), 26 (35%) were ROS positive, and 17 were Endtz positive and found to be ROS positive. Of the 57 Endtz-negative patients, 9 (15%) were ROS positive. The positive Endtz test results correlated strongly with positive ROS formation in patients and donors (P < 0.001). CONCLUSIONS: Our results indicate that the simple, cost-efficient Endtz test could be used as an indicator of excessive ROS formation in semen.

Humans↗
PubMed1995

Incidence and level of seminal reactive oxygen species in normal men.

OBJECTIVES: Excessive formation of reactive oxygen species (ROS) in human semen has been associated with impaired sperm function and fertility potential. The presence of ROS in semen specimens from normal fertile men emphasizes the importance of defining a normal range of ROS formation. The purpose of this study was to establish a normal range of ROS generation and to investigate the effect of sperm concentration on the ROS level. METHODS: ROS was determined in 15 healthy donors and 20 men with suspected infertility. After the sperm concentration in normal donors was adjusted to 20 x 10(6)/mL, ROS was measured by chemiluminescence using luminol in a Berthold luminometer. A specimen was regarded as positive (abnormal) when the value was at least 10 x 10(4) counts per minute (cpm). ROS was also evaluated at 4 sperm concentrations (60, 30, 15, and 7.5 x 10(6)/mL) from samples obtained from the patients with suspected infertility. In addition, ROS was measured in 7 ROS-positive specimens at a sperm concentration of 15 x 10(6)/mL and 60 x 10(6)/mL. RESULTS: Results showed that ROS formation was negative in all 15 healthy donors (median, 0.9 x 10(4) cpm; interquartile range, 0 to 1.48 x 10(4) cpm). The ROS formation value among all the donors was less than 5.5 x 10(4) cpm. ROS formation was positive in 8 (40%) of the suspected infertile patients. ROS levels were significantly lower at sperm concentrations of 15 x 10(6)/mL or 7.5 x 10(6)/mL compared with 30 x 10(6)/mL or 60 x 10(6)/mL (P = 0.05). The ROS level increased after centrifugation for 10 minutes at 500 g in all 7 specimens at both 15 and 60 x 10(6)/mL. However, the increase in ROS formation at 60 x 10(6)/mL was significantly greater than that at 15 x 10(6)/mL (P < 0.001). CONCLUSIONS: A range of ROS formation of 0 to 5.5 x 10(4) cpm at a sperm concentration of 20 x 10(6)/mL may be considered as normal for healthy donor semen. The positive relationship between ROS formation and sperm concentration at the time of measurement emphasizes the importance of concentration adjustment before analysis when comparing ROS levels between different specimens.

Adult↗