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Biomedical subjects

R E Price

Publications and source records attributed to R E Price.

51 records · Page 3Linked to original sources
PubMed1993

Modulation of the intracellular survival of Brucella abortus by tuftsin and muramyl dipeptide.

Tuftsin, a physiologic bioactive peptide of animal origin, and muramyl dipeptide, a synthetic bioactive glycopeptide of microbial origin, are known to enhance several recognized macrophage functions and increase non-specific resistance of the host against a number of pathogens. The influence of these two bioactive peptides was studied in permissive bovine mammary macrophages that were unable to control the intracellular replication of Brucella abortus and restrictive bovine mammary macrophages that were able to effectively reduce the intracellular survival of B. abortus. Addition of tuftsin (Thr-Lys-Pro-Arg) or muramyl dipeptide significantly (P < 0.03) enhanced the ability of the permissive macrophages to control the intracellular replication of B. abortus strain 2308 and resulted in the functional conversion of the permissive macrophages into restrictive macrophages. Addition of tripeptide tuftsin fragment (Lys-Pro-Arg), a natural inhibitor of tuftsin, to the medium completely abrogated the effect of tuftsin (P < 0.03). No additive effect on the ability of the macrophages to control the survival of B. abortus resulted from the combination of tuftsin and muramyl dipeptide.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Pathologic changes occurring in the prostate following transurethral laser prostatectomy.

Serial gross and histopathologic examinations of the prostate following transurethral laser prostatectomy in the canine model demonstrated an immediate well-demarcated sphere of thermal necrosis measuring 2.7 cm in diameter, which, within 24 hours, had begun liquefaction and was showing multiple areas of cavitation. By the end of the 1st week, the areas of cavitation had coalesced to form a central cavity lined by a narrow layer of necrotic tissue clinging to the thin surviving peripheral belt of prostatic glandular parenchyma. At 3 weeks, the bluish-black discoloration resulting from breakdown of blood in the necrotic tissue had subsided, leaving masses of coagulonecrotic tissue within the central cavity. Within 5 weeks, the ectatic central cavity was lined by transitional epithelium. These postmortem pathologic observations confirm our surgical and clinical impressions of being able to satisfactorily perform an effective transurethral prostatectomy using neodymium:YAG (Nd:YAG) laser photoirradiation.

Animals↗
PubMed1992

Use of the holmium:YAG laser in urology.

The tissue effects of a holmium:YAG (Ho:YAG) laser operating at a wavelength of 2.1 mu with a maximum power of 15 watts (W) and 10 different energy-pulse settings was systematically evaluated on kidney, bladder, prostate, ureteral, and vasal tissue in the dog. In addition, various urologic surgical procedures (partial nephrectomy, transurethral laser incision of the prostate, and laser-assisted vasovasostomy) were performed in the dog, and a laparoscopic pelvic lymph node dissection was carried out in a pig. Although the Ho:YAG laser has a strong affinity for water, precise tissue ablation was achieved in both the contact and non-contact mode when used endoscopically in a fluid medium to ablate prostatic and vesical tissue. Using the usual parameters for tissue destruction (blanching without charring), the depth of thermal injury in the bladder and ureter was kept superficial. In performing partial nephrectomies, a 2-fold reduction in the zone of coagulative necrosis was demonstrated compared to the use of the continuous wave Neodymium:YAG laser (Nd:YAG). When used through the laparoscope, the Ho:YAG laser provided precise cutting and, combined with electrocautery, allowed the dissection to proceed quickly and smoothly. Hemostatic control was adequate in all surgical procedures. Although the results of these investigations are preliminary, our initial experience with the Ho:YAG laser has been favorable and warrants further investigations.

Aluminum Silicates↗
PubMed1992

Transurethral incision of the prostate using the holmium:YAG laser.

Transurethral incisions of the prostate were made endoscopically in 5 dogs under a fluid medium using a holmium:YAG (Ho:YAG) laser operating at a wavelength of 2.1 microns and with delivery of 1.0 J/pulse in 15 Hz (15 W). Histopathologic examination of tissues collected immediately after surgery revealed irregular crevices outlined by a narrow zone of coagulative necrosis. Ulcerated fissures persisted at 5 and 7 days with the initial stages of epithelial regeneration partially re-epithelializing the ulcerated surfaces. A modest inflammatory response characterized by edema, hemorrhage, and a mixed inflammatory cell infiltrate was also associated with the laser incision sites at 5 and 7 days. Three weeks postlasing, the ulcerated surfaces of the fissures were completely re-epithelialized. At 5 weeks only a slight indentation persisted at the incision sites with minimal changes in the subjacent submucosa and prostatic glandular architecture. Although the results of these investigations are preliminary, we believe that the Ho:YAG laser warrants further clinical evaluation for treating patients with benign prostatic hyperplasia (BPH), urethral strictures, bladder neck contractures, and constrictions of the upper urinary tracts.

Aluminum Silicates↗
PubMed1991

Radiation apoptosis of serous acinar cells of salivary and lacrimal glands.

Xerostomia and xerophthalmia are common and potentially serious local side effects of radiotherapy for head and neck cancer. Clinical observations supported by experimental findings show that radiation, even in low doses, causes acute diminutions of saliva and tears by rapidly killing the serous cells of the salivary and lacrimal glands, respectively. Serous acini of salivary and lacrimal glands have similar developmental, morphologic, and functional characteristics. Serous acinar cells are functionally mature, secretory epithelial cells that normally do not divide and are long lived. Irradiation of the salivary and lacrimal glands of rhesus monkeys resulted in selective death of serous acinar cells within 24 hours. The paradigm for acute radiation seroadenosis is intermitotic or interphase cell death caused by apoptosis.

Animals↗
PubMed1991

Hepatic pathology of the colon carcinogen, azoxymethane, in Hanford-Moore miniature pigs.

Azoxymethane (AOM) is commonly used in colon carcinogenesis studies in rodents. In an attempt to develop a large animal model of human colon cancer, AOM was given to Hanford-Moore miniature pigs. Six pigs were injected intraperitoneally with a single dose of AOM of either 5, 10, 20, 40 or 55 mg per kg body weight. Within 48 h, severe signs of toxicity and death occurred in animals receiving greater than 20 mg per kg AOM. After 30 days, all surviving animals were killed and necropsied. Acute hepatic necrosis with haemorrhage was the major toxic effect of AOM in all animals receiving doses exceeding 20 mg per kg. In a second, longer-term experiment, eight pigs were injected with either 20 mg per kg AOM weekly or 10 mg per kg AOM every other week or a combination of both treatments. Chronic toxic effects were limited to the liver. No colon tumours were observed. It is concluded that this particular species demonstrates marked hepatic sensitivity to the toxic effects of AOM.

Animals↗
PubMed1990

Survival of smooth, rough and transposon mutant strains of Brucella abortus in bovine mammary macrophages.

Transposon mutants offer a unique way to evaluate the role of lipopolysaccharide (LPS) by producing a theoretical single-gene difference between the original strain and the transposon mutant strain. Comparative survival of Brucella abortus smooth strain 2308, rough RB51, smooth strain 19, and two transposon mutant strains (rough strain 2308::Tn5 Lac Z [m106] and rough strain 19::Tn5 Lac Z [m3], was tested in restrictive bovine mammary macrophages that were able to effectively reduce the percentage of intracellular bacterial survival and permissive bovine mammary macrophages that were unable to control the intracellular replication of B. abortus. The theoretical single-gene difference between strain 19 and strain 19::Tn5 lac Z [m3] and between smooth virulent strain 2308 and rough transposon mutant 2308::Tn5 lacZ [m106] is likely related to differences in LPS content or structure. Significant (P less than 0.05) reduction in the survival of rough strain 19::Tn5 Lac Z [m3] with no significant reduction in the rough transposon mutant strain 2308::Tn5 lacZ [m106] indicated that at least one factor other than LPS contributes to the intracellular survival of B. abortus in bovine macrophages.

Animals↗
PubMed1990

Ability of mononuclear phagocytes from cattle naturally resistant or susceptible to brucellosis to control in vitro intracellular survival of Brucella abortus.

The role of bovine mammary macrophages and peripheral blood monocyte-derived macrophages in natural resistance to bovine brucellosis was evaluated. A group of 11 naturally resistant and 10 chronically infected susceptible cows was studied following challenge with Brucella abortus. Macrophages from a greater proportion (P less than 0.026) of naturally resistant cows were significantly superior to macrophages from susceptible cows in their ability to inhibit the in vitro intracellular replication of B. abortus after challenge exposure. Studies of a second group of cows used mammary macrophages from 12 heifers and blood monocyte-derived macrophages from 22 bulls and heifers. These tests were completed before exposure to B. abortus, using mammary macrophages (P less than 0.039) and blood monocyte-derived macrophages (P less than 0.045), and also showed that macrophages from naturally resistant cattle were significantly superior in their ability to control the in vitro intracellular replication of B. abortus. Our data indicate that the mononuclear phagocytes from more than 80% of the resistant cattle controlled intracellular replication of B. abortus significantly better than did mononuclear phagocytes from susceptible cattle. Mononuclear phagocyte function appears to be an important factor in determining natural resistance to bovine brucellosis.

Animals↗
PubMed1987

Seasonal occurrence and distribution of Gasterophilus intestinalis and Gasterophilus nasalis in the stomachs of equids in Texas.

Stomachs of 271 horses and ponies from 2 sources were evaluated for the presence of Gasterophilus intestinalis and G nasalis larvae, through 2 overlapping 12-month periods of bot fly activity in southern Texas. Equids (n = 140) from one source had nearly 96% of their stomachs infected, whereas equids (n = 131) from another source had 44% of their stomachs infected by Gasterophilus spp. Seasonal dynamics of the bot infection indicated the highest average number of bot larvae per infected stomach occurred in the winter and spring. The smallest average number of bots per infected stomach occurred in the fall. Higher percentages of early (2nd instar plus young 3rd instar) larvae of G intestinalis were observed in the fall in equids from both sources. The late (more fully developed older 3rd instar) G intestinalis larvae outnumbered the early larvae in the winter, spring, and summer. Seasonal variation in numbers and development status of the larvae was consistent with the largest period of adult bot fly activity occurring during the fall. The 2 species of bots had different predilection sites of attachment. Gasterophilus intestinalis larvae concentrated in the nonglandular portions of the stomach near the margo plicatus on the cranial (parietal) surface of the stomach and in the most dorsal extent of the saccus cecus. Gasterophilus nasalis larvae attached almost exclusively in the first ampulla of the duodenum. Predilection sites for both Gasterophilus spp occurred in dorsally positioned areas in the alimentary tract favoring increased availability of oxygen.

Animals↗
PubMed1986

Systemic pathologic responses in experimental Psoroptes ovis infestation of Hereford calves.

Nine Hereford calves were infested with Psoroptes ovis and were allowed to develop clinical mange during a 9-week period. Blood, serum, and urine samples were obtained before and after calves were infested and were compared with those from 3 noninfested control calves. All calves were euthanatized and necropsied 9 weeks after they were infested. Gross and microscopic anatomic changes occurred only in the skin. Calves developed typical exudative dermatitis, the extent of which was dependent on population density of mites. Severely infested calves (50% to 70% of skin with dermatitis) developed a mild anemia and lymphopenia with marked neutropenia and variable eosinophilia. There were also increases in fibrinogen, gamma-globulin, and in vitro lymphocyte response to mitogen stimulation and decreases in anion gap cortisol, albumin, albumin/globulin ratio, and fractional Na clearance values. The severity of many of the changes could be correlated with the extent of dermatitis.

Animals↗
PubMedDate not supplied

Magnetic resonance imaging-based prospective detection of intraperitoneal human ovarian carcinoma xenografts treatment response.

The feasibility of applying magnetic resonance imaging (MRI) for conducting prospective studies of intraperitoneal (i.p.) tumor treatment response to chemotherapy and resultant effects on survival in human ovarian carcinoma/nude mouse orthotopic xenograft models was evaluated. Female nude mice were implanted i.p. with either NMP-1 or SKOV-3ip. human ovarian carcinoma cells on day 0. Initial T2-weighted magnetic resonance (MR) images of the abdomens of NMP-1-implanted mice were obtained on day 7 to confirm the presence of nascent tumors; similar confirmations were made on day 14 with mice bearing SKOV-3ip. xenografts. On the initial imaging days, a multiple-dose regimen of cisplatin (CDDP; qd7 x3) was commenced, using 4 or 6 mg/kg treatments with the NMP-1 model and using 6 mg/kg treatments with the SKOV-3ip. model. Mice were reimaged multiple times, 2 days following each CDDP injection and at later times as well, depending on host survival. The images for each mouse from the last imaging day (day 30 for NMP-1, day 44 for SKOV-3ip.) were used in a blinded fashion to attempt to visually distinguish control from treated mice and to determine whether MRI could predict a survival benefit. For SKOV-3ip. mice, ten out of ten mice were correctly segregated into the control or the CDDP treatment group based solely on these blinded, nonquantified MR results. In this model, the 6 mg/kg multiple-dose regimen achieved a modest response, improving life span by approximately 24%. However, for the NMP-1 mice, only six out of nine evaluable mice were correctly segregated into the control or one of the treatment groups by similar MRI criteria, a virtually random distribution; further, neither CDDP treatment regimen achieved a significant improvement in survival in this model. In another study, NMP-1-implanted mice were treated on day 7 after tumor implantation with a single injection of a hyaluronic acid-paclitaxel copolymer. Control and treated mice were MR imaged on day 28, which revealed marked reductions in tumor burden in treated mice, correlating well with a subsequently observed improved survival of approximately 40%. Our results suggest that MRI can be used to serially and noninvasively monitor treatment response and predict ongoing treatment effects on survival.

Animals↗
PubMedDate not supplied

Transurethral canine prostatectomy with the Nd:YAG laser.

Although laser energy in combination with conventional techniques has been used to ablate prostatic tissue in the dog, the use of the Nd:YAG laser alone to perform transurethral prostatectomies has not been feasible because of the difficulty of directing the laser energy into the prostate. In this study, a 600-microns quartz laser fiber with an attached gold-plated metal alloy reflector and a 1.06-microns Nd:YAG laser were used to perform transurethral laser prostatectomies in 10 mongrel dogs. Each dog received approximately 3600 J to each quadrant of the prostate. No signs of urinary incontinence were noted in any of the dogs postoperatively. Transurethral laser prostatectomies can be performed safely and effectively in the dog and can significantly decrease the incidence of postoperative urinary incontinence.

Animals↗