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Biomedical subjects

D M Phillips

Publications and source records attributed to D M Phillips.

At least 145 records · Page 8Linked to original sources
PubMed1983

Enhanced tracheal mucus clearance with high frequency chest wall compression.

The clearance of mucus in the trachea during high frequency chest wall compression (HFCWC) was studied in nine anesthetized dogs. High frequency chest wall compression was applied by oscillating the pressure in a thoracic cuff such that it produced oscillatory tidal volumes of 25 to 100 cc at frequencies of 3 to 17 Hz. The tracheal mucus clearance rate (TMCR) was determined by direct observation of the rate of displacement of a charcoal particle spot by means of a fiberoptic bronchoscope. Baseline TMCR during spontaneous breathing averaged 8.2 +/- 5.6 mm/min in the 9 dogs. The TMCR during 2 min of HFCWC was increased at 5, 8, 11, 13, 15, and 17 Hz but not at 3 Hz. The enhancement of clearance was most pronounced in the range of 11 to 15 Hz, reaching a peak value of 340% of control at 13 Hz. These studies suggest that HFCWC might be of considerable potential benefit as a mode of chest physiotherapy.

Animals↗
PubMed1983

Spermatogenesis in vitro: completion of meiosis and early spermiogenesis.

In vitro formation of haploid spermatids has not been convincingly demonstrated in mammals. To investigate this problem we selected defined segments of rat seminiferous tubules containing late pachytene and diakinetic primary spermatocytes (Stages XII and XIII of the cycle) for culture in a chemically defined medium. After 2 days, most spermatocytes completed both meiotic divisions, and by 6 days the tubular epithelium developed morphologic characteristics of Stage V in which the newly formed spermatids had acrosomic systems characteristic of step 5 spermiogenesis. The seminiferous tubules also differentiated biochemically as evidenced by increased production of proteins characteristically secreted by Stage V. Since this in vitro differentiation of the germinal epithelium occurred in the absence of testosterone and FSH, we conclude that late pachytene spermatocytes and their associated Sertoli cells have all the information required for both meiotic divisions and early spermiogenesis.

Animals↗
PubMed1982

Effect of gonadotropins and prostaglandin on cumulus mucification in cultures of intact follicles.

Follicles of 28 day-old pregnant mare serum gonadotropin (PMSG)-primed rats, were cultured for up to 24 hours in the presence or absence of ovine gonadotropins, highly purified rat gonadotropins, dibutyryl cyclic AMP (dbcAMP), methylisobutylxanthine (MIX), choleratoxin (CT), or prostaglandin E2 (PGE2). The morphology of the cumulus-oocyte complexes isolated from these follicles was subsequently examined with the light microscope. Cumulus mucification was studied under the different culture conditions using scanning electron microscopy (SEM) and the hyaluronidase sensitivity test. The features of the cumulus-oocyte complexes in the control cultures did not change throughout the incubation period, while complexes from follicles incubated with LH, FSH, dbcAMP, MIX, CT, or PGE2 changed their appearance and accumulated extracellular mucoid material. Treatment of these cumuli with hyaluronidase resulted in lysis of the extracellular mucus and dispersal of the cumulus masses. The results of this study agree with our earlier observation that the maturation of the cumulus-oophorus, which occurs in vivo following the LH surge, can be induced in vitro by either gonadotropins or cAMP. Prostaglandin E2 did not affect cumulus cells, unless incubated enclosed by their follicles. This suggests that this hormone may influence the cumulus cells indirectly, probably via other components.

1-Methyl-3-isobutylxanthine↗
PubMed1982

Sperm penetration into rat ova fertilized in vivo.

The mechanics of sperm entry into the oocyte were examined in rat ova fertilized in vivo. With the scanning electron microscope we observe that the spermatozoon is first associated with the oocyte by the region of the convex surface of the sperm head which is immediately anterior to the postacrosomal region. At this early stage the anterior tip of the sperm head is directed away from the oocyte surface. The spermatozoon subsequently appears to rotate so that it comes to lie on its "side." The membrane over the sperm head becomes free of microvilli and a large incorporation cone is subsequently formed. It is concluded that in the rat initial fusion of sperm and egg probably occurs between the oolemma and the sperm plasmalemma over the equatorial segment of the acrosome at the convex surface of the sperm head which is just anterior to the postacrosomal region.

Animals↗
PubMed1982

Deficiency of protein-carboxyl methylase in immotile spermatozoa of infertile men.

We studied protein-carboxyl methylase, an enzyme involved in the regulation of cellular locomotion in both bacteria and leukocytes, in semen from 22 normal fertile men, 10 vasectomized volunteers, and nine infertile patients with nonmotile spermatozoa. In normally motile spermatozoa protein-carboxyl methylase activity was 68.8 +/- 5.5 pmol per milligram of protein (mean +/- S.E.). On the other hand, the enzyme activity in nonmotile spermatozoa from the infertile patients was low (17.4 +/- 3.4 pmol per milligram of protein) and similar to that in the cellular debris from the vasectomized volunteers (10.4 +/- 1.3 pmol per milligram of protein). The low enzyme activity in the infertile patients was not caused by the presence of dead spermatozoa or spermatozoa with leaky plasma membranes, since mitochondrial protein synthesis and lactate dehydrogenase activity were normal in these patients. The deficiency of protein-carboxyl methylase activity in nonmotile sperm is probably not due to a primary genetic defect, since the enzyme activity is normal in the red cells of these patients and spontaneous recovery of motility is associated with the return of enzyme activity.

Adult↗
PubMed1982

Binding of epithelial cells to lectin-coated surfaces.

Epithelial cells may relate to their basement membrane substrates via lectin-like interactions. In a model system for study of this type of interaction, lectin-coated bacteriological plastic petri dishes were presented as substrates for epithelial cell adhesion. Of 21 lectins tested by mixed agglutination against two epithelial cell types, Madin-Darby canine kidney (MDCK), and human embryonic kidney cells (HEK), nine gave less than 5% rosettes and 12 gave 5 to 50% rosettes. Wheat germ agglutinin (WGA) and Geodia cydonium lectin gave the highest percentage of rosettes. Wheat germ agglutinin was readily adsorbed to plastic surfaces and maintained specificity in binding interactions. Both MDCK and HEK cells attached as well to WGA coated petri dishes as to conventional tissue culture dishes. Furthermore, both spread over the lectin-coated surfaces. The MDCK cells grew to confluence and could be subcultured and maintained indefinitely on such surfaces, although WGA in solution was toxic to the cells in concentrations as low as 0.1 to 1.0 microgram/ml. Cell attachment to WGA coated dishes was blocked by cycloheximide only if the cells had been preincubated with the inhibitor for several hours. Cell attachment was not inhibited by pretreatment of cells with neuraminidase. Precoating cells with WGA blocked binding to both WGA-coated surfaces and untreated tissue culture dishes. Cells attached to WGA-coated dishes could not be readily dislodged by trypsin-EDTA for the first 2 h after subculture. By 4 h, attachment was again trypsin sensitive, suggesting that the cells synthesized a trypsin-sensitive material that was laid down between the cell surface and the WGA-coated dish. Regeneration of trypsin sensitivity was not blocked by cycloheximide.

Animals↗
PubMed1982

Role of opsonins in clinical response to granulocyte transfusion in granulocytopenic patients.

Fifty febrile severely granulocytopenic patients were given four daily transfusions of 2.2 X 10(10) normal donor granulocytes. Twenty-three (46 percent) responded clinically, although both responders and nonresponders were similar in clinical characteristics at the outset. This study examines the relation between serum opsonic activity before initiation of granulocyte administration and clinical response. Opsonic activity to three test organisms (Escherichia coli 286 and ON 2, and Staphylococcus aureus) and to 15 blood stream isolates from 14 patients was measured as serum-dependent uptake of heat-killed 14C-labeled bacteria by normal donor leukopheresis granulocytes in an in vitro assay and compared with results obtained with a standard normal serum in each assay. At a concentration of 8 percent serum, all patient groups were equivalent to standard (90 to 102 percent) for the three test organisms. When rate-limiting concentrations of serum (1 to 2 percent) were employed, opsonic activity remained similar to standard for S. aureus in all patient groups and for the two E. coli strains in responders (82 to 98 percent). In contrast, opsonins for E. coli decreased to 41 to 50 percent of standard in nonresponders (p less than 0.01). When patients with proved infection were separately analyzed, opsonin activity for E. coli 286 and ON 2 was significantly greater in responders than nonresponders (73.6 versus 34.9 percent and 124.8 versus 58.1 percent, respectively for the two strains) (p less than 0.01). Patients with opsonin activity of 50 percent or greater of standard had a greater response rate (73 versus 19 percent and 45 versus 0 percent for the two E. coli strains) (p less than 0.005 and p = 0.08, respectively). Eight of 10 patients with 75 percent or greater of standard for opsonic activity against their own blood stream isolates also responded, whereas zero of four with opsonins less than 75 percent of standard had a favorable outcome. These results indicate that serum opsonic activity may be a determinant of clinical response to granulocyte transfusion in infected granulocytopenic patients and may be predictive of outcome. We conclude that opsonic activity should be assessed in such patients before granulocyte administration and suggest a trial of plasma infusion in opsonin-deficient patients.

Adolescent↗
PubMed1982

Beta-endorphin is present in the male reproductive tract of five species.

Previous studies from this laboratory have demonstrated immunostainable beta-endorphin-like material (beta-EP) in Leydig cells and epithelia of the epididymis, seminal vesicle and vas deferens of the rat. These observations would be strengthened if it could be demonstrated that they were not a peculiarity of the rat. Accordingly, we now present immunocytochemical evidence for the presence of beta-EP in the Leydig cells of mouse, hamster, guinea pig and rabbit. No immunoreactive material was identified in Sertoli, myoid, endothelial or germ cells of any of the species examined. Immunostainable beta-EP was also demonstrated in the epididymides of mouse, guinea pig, rabbit, and rat, but not hamster. Immunostainable material was also present in the epithelia of the vas deferens and seminal vesicles of mouse and rat, the only two species thus far examined. Since beta-EP was present in Leydig cells, we wondered whether this peptide could be identified in other steroid-producing tissues. When rat ovaries and adrenals were reacted with anti-beta endorphin, staining was demonstrated in corpus luteum and adrenal cortex. No staining was observed in the adrenal medulla or other portions of the ovary. In order to determine whether the beta-EP detected in the testis and epididymis was derived from a pituitary source, animals were hypophysectomized and tissues examined 2 weeks later. Both the Leydig cells and the epididymal epithelium remained immunostainable. In summary, immunostainable beta-EP has been identified in Leydig cells of five species. Stainable material is also present in the epithelium of other portions of the male reproductive tract and in steroid-secreting cells of the ovary and the adrenal. Such beta-EP may have a paracrine function in the testis and other portions of the male reproductive tract.

Adrenal Glands↗
PubMed1982

Cultivation and partial characterization of spiroplasmas in cell cultures.

Spiroplasmas were propagated in the Drosophila melanogaster cell line Dm-1. Spiroplasma citri and unidentified strains (corn shunt organism, 277F [tick isolate], powder puff, BNR-1, honey bee, and OBMG) grew to 10(8) to 10(9) colony-forming units per ml and could be passaged. Cytopathic effect (CPE) varied with the infecting spiroplasma. The honey bee isolate killed Dm-1 within 2 to 4 days and produced CPE in four mammalian cells tested. At 25 degrees C, suckling mouse cataract agent produced no CPE in Dm-1 cells. Dm-1 cells did not support growth of the spiroplasmal sex ratio organism. Spiroplasmas could be detected in the cell cultures by agar inoculation, dark-field microscopy, scanning electron microscopy, and DNA fluorescent staining. The uridine phosphorylase test showed significant levels of conversion of [14C]uridine to [14C]uracil for all but some plant isolates: S. citri, corn shunt organism, lettuce, cactus, and powder puff strains, the first mycoplasmas to lack the enzyme. Primary isolations of corn shunt organism from infected corn plants were made in Dm-1 and I-XII cultures. The course of corn stunt organism infection of Dm-1 was monitored for three passages. The use of agarose and Dienes staining of the colonies improved growth and colony counting of corn stunt organism. The number of viable infected DM-1 cells decreased from 1.2 x 10(7) at passage 1 to 7.0 x 10(6) at passage 2 and 3 x 10(5) at passage 3.

Animals↗
PubMed1980

Surface properties of the zona pellucida.

Structural and sperm binding properties of the hamster zona pellucida (ZP) were investigated using the scanning electron microscope (SEM). The internal and external surfaces of the ZP were found to be morphologically dissimilar. The external surface displayed a fenestrated lattice-like appearance, whereas the internal surface showed a regular rough appearance. In order to investigate the physiological characteristics of the ZP, zonae were incubated with the vitro capacitated spermatozoa for five minutes and subsequently prepared from SEM examination. Numerous non-acrosome-reacted spermatozoa and dissociated acrosomes were observed associated with the external surface of the ZP. Spermatozoa or acrosomes were, however, not observed associated with the internal surface of the zona. Acrosome-reacted spermatozoa did not adhere to the ZP. It was concluded that the external and internal surfaces of the zona are morphologically and physiologically dissimilar.

Acrosome↗
PubMed1980

Mycoplasmal infection of lymphocyte cell cultures: infection with M. salivarium.

Many conclusions concerning cell culture mycoplasmas are based on data from studies in fibroblast cultures. Some conclusions may not be valid in other types of differentiated cell cultures. M. salivarium was isolated from 35 human lymphocyte cultures (HLC), 34 from the same laboratory. The organism grew to more than 10(8) colony forming units (CFU) per ml of lymphocyte suspensions and was readily detectable by microbiological culture, uridine phosphorylase, and uridine/uracil assays. Direct mycoplasmal assays on HLC by DNA fluorochrome staining and scanning electron microscopy (SEM) yielded artifacts that interfered with diagnosis. For DNA and SEM of HLC, inoculation into indicator cell cultures is recommended. M. salivarium infection of HLC did not produce any immediate difference in growth rates; however, infected cultures eventually died 14 to 29 passages after infection in contrast to uninfected controls. The same organism in 3T6 fibroblasts effected a 60% decrease in growth rate. Although M. salivarium is a frequent isolate from the oral cavity, it is a rare cell culture isolate. M. salivarium was able to initiate growth over a wide pH range, grew as well in cell cultures as in cell-free media, and was resistant to 50 microgram per ml of gentamycin, tylocine, kanamycin, and erythromycin. By Cot1/2 analysis, M. salivarium had a genomic molecular weight of 4.2 X 10(6) daltons. M. salivarium did not increase chromosome aberrations in one HLC. Some of these results have application to infection of HLC by other mycoplasmal species.

Anti-Bacterial Agents↗
PubMed1980

The localization of protein carboxyl-methylase in sperm tails.

Protein carboxyl-methylase (PCM), an enzyme known to be involved in exocytotic secretion and chemotaxis, has been studied in rat and rabbit spermatozoa. PCM activity and its substrate methyl acceptor protein(s) (MAP) were demonstrated in the supernate after solubilization of the sperm cell membrane by detergent (Triton X-100). A protein methylesterase that hydrolyzes methyl ester bonds created by PCM was demonstrated in rabbit but not in rat spermatozoa. This enzyme was not solubilized by nonionic detergent. The specific activities of PCM in rat spermatozoa from caput and cauda epididymis were similar and lower than that found in testis. By contrast, MAP substrates were low in testis and increased in parallel with sperm maturation in the epididymis. Multiple MAP were demonstrated in spermatozoa by polyacrylamide gel electrophoresis. The pattern of these proteins was similar in spermatozoa from different portions of the reproductive tract. Fractionation of heads and tails of rat spermatozoa on sucrose gradients indicated that PCM was found exclusively in the tail fraction, whereas MAP was detected both in head and tail fractions. The presence of all the components of the protein carboxyl-methylation system in spermatozoa and the localization of PCM and some of its substrates in the sperm tail are consistent with their involvement in sperm cell motility.

Animals↗