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Biomedical subjects

P B Pendergrass

Publications and source records attributed to P B Pendergrass.

At least 19 recordsLinked to original sources
PubMed2000

Comparison of vaginal shapes in Afro-American, caucasian and hispanic women as seen with vinyl polysiloxane casting.

Full vinyl polysiloxane casts of the vagina were obtained from 23 Afro-American, 39 Caucasian and 15 Hispanic women in lying, sitting and standing positions. A new shape, the pumpkin seed, was found in 40% of Afro-American women, but not in Caucasians or Hispanics. Analyses of cast and introital measurements revealed: (1) posterior cast length is significantly longer, anterior cast length is significantly shorter and cast width is significantly larger in Hispanics than in the other two groups and (2) the Caucasian introitus is significantly greater than that of the Afro-American subject.

Black People↗
PubMed1996

The shape and dimensions of the human vagina as seen in three-dimensional vinyl polysiloxane casts.

Full vaginal casts of 39 caucasian women, 13 each nulliparous, uniparous and multiparous, were made using vinyl polysiloxane impression material. Vaginal lengths were measured with polished acrylic rods inserted by the subjects, and introital diameters were measured with conical polypropylene flasks. Parallel sided, conical, heart, and slug shapes were found. Lengths ranged from 6.86 to 14.81 cm; widths ranged from 4.8 to 6.3 cm; introital diameters ranged from 2.39 to 6.45 cm. No significant differences by parity or shape were found.

Female↗
PubMed1986

A comparative study of cytological and physiological parameters of semen obtained from alcoholics and non-alcoholics.

Sixty subjects between the ages of 18 and 50 were used in this study. Thirty of these were known alcoholics undergoing detoxification and treatment while the remainder were non-alcoholics of known fecundity. Semen samples from each subject were evaluated for volume, pH, and sperm viability, motility and concentration. While semen volume was significantly greater in the alcoholic group, the other parameters were similar in the two groups. Complete seminal cytological profiles were obtained for the men in both groups; the alcoholic group was found to contain nearly 30% fewer normal cells than the controls. Cytological aberrancies present in the greatest numbers included coil-tailed sperm, immature testicular cells and amorphous cells, all of which were present in significantly greater ratios in the semen of the alcoholics. In addition, when all other observed spermatozoan aberrations were grouped into one category this group, too, was significantly greater in the alcoholics.

Alcoholism↗
PubMed1985

Effect of small doses of aspirin and acetaminophen on total menstrual loss and pain of cramps and headache.

90 women participated in a 4-month study. During the first 2 periods, they took no pain relievers whatsoever; during their last 2 periods they took 2 X 325 mg aspirin, acetaminophen or an identically packaged placebo every 4 h to total 8 tablets during the first 24 h of their periods beginning with spotting. For statistical analysis, periods 1 and 2 were combined and averaged, then compared with periods 3 and 4 combined and averaged. Total menstrual loss in grams, number of days of flow, and pain of cramps and headaches were analyzed by MANOVA for each of the three treatment groups. An ANOVA for each of these variables as well as for daily menstrual loss for the first 3 menstrual days was also performed. The MANOVA for all variables by the three treatment groups failed to show any significant differences. Similarly, ANOVAs for the individual variables failed to indicate significant differences except for the variable pain of cramps (p = 0.0072). The Duncan's Multiple Range Test for pain of cramps showed that the average pain for the placebo group was higher than for either the aspirin or the acetaminophen group, although the means for these two groups were not significantly different. These results indicate that neither aspirin nor acetaminophen in the doses given alter either total menstrual loss or the pattern of loss during the first 3 menstrual days. However, both preparations were found to be more effective than placebo in reducing pain of cramps.

Acetaminophen↗
PubMed1984

Umbilical vessels of spontaneously hypertensive rats.

Umbilical vessels of spontaneously hypertensive rats, control strain Wistar-Kyoto rats and rats treated with alpha-methyldopa were compared using the scanning electron microscope and light microscope. Observations with the scanning electron microscope revealed that the venous endothelial cells were relatively flat, giving the luminal surface of the vein a smooth appearance. The nuclear region of the fusiform arterial endothelial cells was responsible for the bumpy appearance of the luminal surface of the artery. Microvilli were a consistent feature of the endothelium in both umbilical vessels. There was no consistent pattern of distribution or density of microvilli within either vessel, but microvilli were more abundant on the luminal surface of the artery than in the vein. The luminal surface of some endothelial cells of the artery had long straight processes which crossed several cells before terminating. Light microscopic observations revealed that the endothelial cells and cells of the tunica intima and media contained an abundance of glycogen. The same layers stained sparsely for acid glycosaminoglycans. Maternal hypertension and treatment of spontaneously hypertensive rats with the antihypertensive drug, alpha-methyldopa, did not result in significant morphological alterations of either the endothelium or tunica media of the umbilical blood vessels.

Animals↗
PubMed1984

Do aspirin and acetaminophen affect total menstrual loss?

Two commonly taken over-the-counter analgesics, aspirin and acetaminophen, were compared for: effect on total menstrual loss, effect on total days of menstruation, and effect in reduction of pain due to headaches and/or menstrual cramps. Drugs were administered during a 4-month study according to a double-blind format. During the first 2 months, subjects ingested no drugs whatsoever during their menstrual periods. During the second 2 months, subjects ingested aspirin, acetaminophen, or placebo at the rate of two 325-mg tablets every 4 h to total 8 tablets per day during the first 3 days of their menstrual periods. Statistical analysis of the first 2 periods compared to the last 2 showed no differences in total menstrual weights. The number of days of menstruation in the placebo group was significantly lower (p = 0.0137) than in its own control or in the other groups. Neither analgesic showed a significant reduction in pain due to headache or cramps, although acetaminophen appeared to be slightly more effective than aspirin in reducing menstrual cramps.

Acetaminophen↗
PubMed1984

The effect of an H1 blocker, chlorpheniramine maleate, on total menstrual loss.

50 subjects participated in a 4-month study of the effects of an antihistamine on total menstrual loss. During the first 2 periods, no drugs were given; during the last 2 periods, an antihistamine or a placebo was administered according to a double-blind format. The menstrual weights of the first 2 months were averaged and compared with averages from the last 2 months combined. The treated group showed an average decrease in menstrual loss of 11.30 g compared to a decrease of 0.98 g in the placebo group. While the difference in means was not statistically significant, the variance between the 2 groups was significant (p = 0.0002), indicating that the antihistamine, chlorpheniramine maleate, was effective in reducing menstrual loss in certain individuals, but that the effect was neither uniform nor universal.

Adult↗
PubMed1984

A rapid, noninvasive method for evaluation of total menstrual loss.

Three types of packages containing enough sanitary supplies for one menstrual period were weighed and distributed to 100 subjects to determine adequacy of supplies and compliance to protocol. Returned packages were then reweighed to determine total menstrual loss. No subject used all the supplies in her package; therefore, packages contents were deemed ample. 7 subjects added their own purchased products to their packages; since added products were specified by name, weight corrections were easily made. 2 subjects lost unused supplies which were specified, and weight corrections were made accordingly. Evaporative loss from sealed and stored and frequently opened packages was measured. 100 g distilled water were added to contents inside 60 packages which were sealed and set aside 7 days. Average loss from these packages was 0.65 +/- 0.57 g. 5 g water were added to 60 packages 4 times daily for 5 days (100 g total). Then packages were set aside for 2 days and weighed on day 7. Average loss from these packages was 1.25 +/- 0.85 g. The combination of storage plus frequent opening resulted in an average loss of 1.90 +/- 0.87 g. Thus, the direct-weight method permits recovery of 97-98% of sample.

Adult↗
PubMed1983

Bone morphology of weanling rats from dams subjected to fluoride.

Femurs of weanling rats from third-pregnancy litters of dams given 150 ppm fluoride in the drinking water were examined by light-and scanning-electron microscopy. Under the conditions of the experimental procedure, no pathological changes were seen in the femurs as a result of maternal ingestion of fluoride. These results indicate that the amount of fluoride crossing the placenta and mammary gland was insufficient to produce significant morphological changes in the bones of 3-week-old rats.

Animals↗
PubMed1983

Fluoride ingestion during multiple pregnancies and lactations: microscopic observations on bone of the rat.

Female rats were given 150 ppm fluoride in the drinking water during three successive pregnancy and lactation periods; the femoral diaphyses were then examined for morphological alterations by light and scanning electron microscopy to determine the influence of fluoride ingestion during multiple pregnancies and lactations. The periosteal surface was dominated by areas of woven bone formation with some prolonged resting areas around osteocyte lacunae. The endosteal surface consisted mainly of areas of active bone resorption with some areas of bone formation. The interior of the cortex was characterized by numerous resorption cavities and remodeling in secondary Haversian systems. Fluoride, by the nature of its incorporation into bone crystals and by its direct cytotoxic effect on bone resorbing cells, reduces the availability of calcium from bone. It appears that fluoride ingestion during lactation created a heightened state of calcium homeostatic stress. As a result, bone mineral was mobilized by resorption of the endosteal surface and by cavitation of the interior of the cortex. Secondary hyperparathyroidism is thought to play an integral part in an attempt to maintain calcium homeostasis.

Animals↗
PubMed1982

Structural features of a specialized region of the epididymis of the Siberian hamster (Phodopus sungorus).

Light and electron microscopic observations of zone six of the Siberian hamster (Phodopus sungorus) epididymis reveal that two distinct tubule populations exist in this region. The population of smaller tubules apparently arises as diverticula of the larger ducts but, though contiguous, the contents of each remain different and separate. While the larger tubules are laden with sperm and seminal fluid, the smaller ones area filled with degenerating cells and cellular debris. Cytologically, the features of the two tubule types are similar. Both display a prominent Golgi apparatus, substantial amounts of rough endoplasmic reticulum, an extensive population of various lysosomal forms and scattered crystalline inclusions.

Animals↗
PubMed1982

Absorptive structures of the mouse yolk sac placenta and associated placental surfaces. A scanning electron microscope study.

Membranes of the visceral and parietal yolk sacs and their adjacent placental surfaces were examined at 13, 18 and 21 days of gestation in the mouse by scanning electron microscopy. The exterior or endodermal surface of the visceral yolk sac was characterized by a villous area attached to the placental disc, a central transition zone, and a smooth distal area. At all days, the abundant microvilli of the villous region were either elongated or bleb-shaped. At 13 days microvilli of cells in the transitional zone and smooth area were uniformly rod-shaped in contrast to the longer microvilli seen at 18 and 21 days; moreover, denuded cells were frequently seen at 21 days. Large squamous endodermal cells on the surface of the placental disc outside the visceral yolk sac were separated by wide intercellular spaces bridged by cytoplasmic processes at all days. Microvilli of these cells were sparse at day 13 but became abundant at day 18 then decreased by day 21. Endodermal cells of the adjacent parietal yolk sac changed from a rounded to a flattened shape from 18 to 21 days, with microvilli being more abundant at 18 days. In contrast to the outer endodermal surface of the visceral yolk sac, the inner mesothelial surface was devoid of villi. At 13 days contiguous edges of cells interdigitated giving the lateral cell borders a microvillous-like appearance. The surface of these cells had a sparse covering of microvilli which became more abundant as the surface was drawn into folds at 18 and 21 days. The adjacent fetal placental surface was covered by flattened cells with few surface specializations. Our observations support an absorptive role for the endodermal surfaces of the visceral and parietal yolk sacs and the associated surfaces of the mouse placenta.

Animals↗
PubMed1982

Scanning electron microscopy of the femoral epiphyseal plate and metaphysis of the rat after short-term fluoride ingestion.

Anorganic preparations of the distal metaphyseal and epiphyseal regions of the femoral bones from young male rats given 150 ppm fluoride in the drinking water for 10 weeks were examined by scanning electron microscopy. Longitudinal sections of the bones revealed an increase in the zone of mature hypertrophied cells of the epiphyseal plates as compared with controls. The lacunae in this zone varied considerably in size and shape, and were arranged in irregular nests rather than in parallel rows. Within the cavity of the shaft, the amount of cancellous bone was reduced, particularly in the central areas of the metaphyses where the network of trabeculae was sparsely distributed. The trabeculae located in the more peripheral areas of the metaphyses were broad and heavy in appearance. Areas of fully or partially mineralized bone were markedly reduced. The bone surfaces were rough, irregular and covered with numerous Howship's lacunae. The results of this investigation indicate that the initial effects of fluoride on bone include an inhibition of resorption in the epiphyseal plate coupled with an increase in resorption of metaphyseal trabecular bone.

Animals↗
PubMed1982

The effects of fluoride on the periosteal and endosteal surfaces of the rat femur. A scanning electron microscope study.

Anorganic preparations of the femoral diaphyses of male rats given 150 ppm fluoride in the drinking water for 10 weeks were examined by scanning electron microscopy and compared to similar preparations from control, untreated rats. In fluoride-treated rats, the surface features of the periosteum were characteristic of woven bone formation. Apposition areas appeared uneven and frayed, consisting of bunches of poorly-defined needles. The mineralized segments varied in size with wide gaps in between, suggesting a delay in the rate of mineralization at the periosteum. The uneven surface was a reflection of the underlying irregular orientation of the collagen fiber bundles. Numerous osteocyte lacunae buried at various depths were evident, and the lacunar walls were irregular with mineralized segments running in all directions. These features were in contrast to the ordered arrangement of both the collagen fiber bundles and osteocytes seen in typical lamellar bone formation of the untreated animals. On the endosteal surfaces, apposition areas as well as fully mineralized areas appeared similar in both groups. However, well-defined resorption areas were decreased in the fluoride-treated rats. The few Howship's lacunae present on the endosteal surfaces were shallow and poorly formed. These observations of the femoral diaphyses indicate that the ingestion of fluoride for 10 weeks in the rat results in an increase in matrix and bone formation at the periosteum with a concomitant decrease in resorptive activity at the endosteum.

Animals↗
PubMed1982

Developmental changes in the mouse amnion: a SEM study.

Both surfaces of the mouse amnion from 13 to 21 days of gestation were studied by scanning electron microscopy (SEM). The exocoelomic surface is covered by mesenchymal cells and randomly arranged fine fibers at 13 days. By 21 days, these cells are covered by thick fibers frequently arranged in woven pattern. The ectodermal lining of the amniotic cavity at 13 days is characterized by squamous epithelial cells with central patches of short microvilli. An apparent increase in microvilli occurs by 16 days followed by either the loss of microvilli or the formation of microridges by 21 days. These changes may reflect functional changes of the amnion or processes of cell aging.

Amnion↗
PubMed1981

Scanning electron microscopy of the decidual stalk and decidua basalis in the mouse.

Placentas either in situ or mechanically separated from their uterine beds were surveyed by scanning electron microscopy to determine the changing relationship of the placenta to its uterine bed with special reference to alteration in the decidual basalis accompanying parturition. At 13 days gestation the placenta is connected to the uterus by a short, broad decidual stalk which becomes longer and more constricted by term. The stalk is covered by a layer of squamous epithelium. Mechanical separation of the placenta and uterus in early gestation reveals that the entire decidual basalis of the decidual stalk is composed of large coarse fibers. As gestation progresses, a relatively smooth acellular capsule forms around the base of the placenta. However, the center of the decidua basalis, the core of the stalk, continues to be composed of large coarse fibers throughout gestation and appears to be the only region penetrated by maternal vessels.

Animals↗
PubMed1981

Scanning electron microscopy of corpus luteum formation in the golden hamster.

SEM observations of corpus luteum formation in the golden hamster reveal considerable cellular migration occurring in both the newly forming luteal mass and the remaining surface epithelium. During the first 24 h of the 4-day cycle, cells in the luteal mass become aligned into cords which obliterate the crater-like rupture. Individual cords lose their distinct surface profiles as the luteal mass forms a mushroom-like cap, the edges of which overhang surface epithelial cells (SEC) bordering the rupture site. The luteal mass continues to be remodeled as the edges slowly recede during the next 3 days of the cycle, and the follicle assumes a more spherical shape with a slightly sunken apex as regression begins. Covering of the rupture site by the SEC is a slow process which involves two mechanisms. Most of the mass is gradually covered by finger-like columns of SEC which migrate from the collar of cells surrounding the luteal mass to slowly surround, then cover small spherical or oval regions of the slightly sunken mass. In addition, individual SEC migrate out of the collar and move up onto the mass. The entire covering process appears to be random and poorly coordinated until very late in the 4-day cycle. This is attributed to changing surface properties of the luteal mass during the cycle.

Animals↗