Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Charles P. Davis is active.

Publication


Featured researches published by Charles P. Davis.


The Journal of Urology | 1984

Urothelial Hyperplasia and Neoplasia: A Response to Chronic Urinary Tract Infections in Rats

Charles P. Davis; Marc S. Cohen; Michael B. Gruber; Michael M. Warren

The rat was used as an animal model to examine the effect of foreign bodies and long term infection (24 weeks) on bladder epithelium. Stainless steel wire implants and multiple injections of Escherichia coli were compared to control rat bladders by gross observation, light microscopy and scanning electron microscopy. Hyperplastic alterations, (papilloma, von Brunns nests), dysplasia (squamous metaplasia, microvilli) and early lesions consistent with neoplasia occurred in rats with bladder implants and multiple bacterial injections but not in controls. Epithelial changes were not associated with sterile bladder implants. Bladder papillomata could be observed as early as 2 weeks in rats having both an implant and an infection, but the majority of hyperplastic and early neoplastic-like changes occurred after 6 weeks. Long-term infections, both with and without a bladder implant, can lead to lesions consistent with neoplasia in bladder epithelium.


American Journal of Emergency Medicine | 1995

Ketorolac versus meperidine-plus-promethazine treatment of migraine headache: evaluations by patients.

Charles P. Davis; Paul R Torre; Charles Williams; Charles Lanford Gray; Kevin Barrett; Gus Krucke; Dwight Peake; Bill Bass

This study was designed to compare and contrast the speed and efficacy of meperidine (75 mg)/promethazine (25 mg) intramuscularly to ketorolac (60 mg) intramuscularly, in a double-blind study in reducing the symptoms of migraine headache. Forty-two patients who presented to the emergency department between July 1992 and February 1993, with previous diagnoses of migraine headache, were considered for this study. Patients subjectively evaluated parameters of their migraine headaches (eg, pain and nausea) using a numeric scale and were later asked to reevaluate these same parameters at 30, 60, and 360 minutes after a single intramuscular injection of either ketorolac (60 mg) or meperidine (75 mg)/promethazine (25 mg). Sixty-eight percent of patients given meperidine/promethazine responded whereas 55% of patients given ketorolac responded. The responder group showed a statistically significant reduction in headache within 30 minutes with both drug regimens. There was no statistically significant difference between the number of responders in either group. The responders from both groups had relief that lasted 6 hours after injection. In the nonresponder groups, most of the patients withdrew within 1 hour after treatment. As determined by patient response to treatment of their migraine headaches, there was no statistically significant difference between the ketorolac and the meperidine/promethazine groups.


The Journal of Urology | 1987

Urinary Carcinogen [Nitrosamine] Production in a Rat Animal Model for Ureterosigmoidostomy

Marc S. Cohen; Michael E. Hilz; Charles P. Davis

Tumor development at the site of ureterointestinal anastomosis is a recognized complication in patients undergoing ureterosigmoidostomy. In order to explore the hypothesis that carcinogens (nitrosamines) may be a factor in ureterosigmoidostomy, female Sprague-Dawley rats (n = 125) underwent urethral ligation, bladder dome resection and anastomosis of the bladder trigone to an opening in the anterior rectosigmoid wall. Biweekly nitrosamine determinations were performed on the resultant urine-feces slurry by gas chromatography up to thirty-two weeks post surgery. Nitrosamine (N,N-dimethylnitrosamine) was noted as early as two weeks after surgery in 39% (11/28) of rats. One hundred percent of animals consistently demonstrated nitrosamine by week 14 (32 rats). Nitrosamine levels increased throughout the study with a peak level after thirty-two weeks of 0.275 micrograms./ml. Only a portion (n = 40) of the total animal population was deemed suitable for pathologic examination secondary to animal demise and autolysis at autopsy related to infection and obstruction. In these animals, no adenocarcinoma was found although hyperplastic changes and metaplastic changes were demonstrable at nine days and eight weeks respectively. In one animal a grade I transitional cell papilloma was identified after eight weeks. Control animals demonstrated no nitrosamine production. In vitro combinations of rat urine and feces yielded nitrosamine after six weeks. The absence of adenocarcinoma tumor development is believed indirectly related to animal demise in that not enough time had elapsed to allow significant tumor development. This study lends support to the concept that nitrosamines may play a role in the development of hyperplasia, dysplasia and eventual neoplasia in ureterosigmoidostomy.


The Journal of Urology | 1992

Electrode and Bacterial Survival with Iontophoresis in Synthetic Urine

Charles P. Davis; S.L. Hoskins; Michael M. Warren

Urinary catheters, especially in patients with long-term catheter requirements, frequently are a source of infection. Iontophoresis has been proposed as a method to decrease or eliminate such infections. Several types of material were examined for their potential use as electrodes in an iontophoretic catheter system. Silver, copper and nickel electrodes did kill microorganisms but did not show longevity. Carbon and gold electrodes showed longevity and killing of microorganisms. Gold proved to be somewhat better than carbon in killing Klebsiella pneumoniae in a broth. Few organisms survived iontophoresis. Those few that survived (mainly Klebsiella in broth), when rechallenged by iontophoresis, did not show any striking resistance to iontophoresis. Our data support the proposition that inclusion of electrodes, depending on the electrode type, in a catheter probably will decrease or eliminate a bacterial population in urine and, thus, may help prevent catheter-related infections and their sequelae.


American Journal of Emergency Medicine | 1993

Ketorolac as a rapid and effective treatment of migraine headache: evaluations by patients.

Charles P. Davis; Paul R Torre; Nathan C. Schafer; Bharat Dave; Bill Bass

The objective of this study was to determine the speed and efficiency of ketorolac in reducing the symptoms of migraine headache. Twenty-three patients who presented in the emergency department during the period between April and July 1992 with a previous diagnosis of migraine headache were considered for the study. Patients subjectively evaluated parameters of their migraine headaches (eg, pain and nausea) with a numerical scale and were asked to re-evaluate these same parameters at 30, 60, and 360 minutes after a single injection of Ketorolac. Seventeen (74%) patients reported a decrease in headache symptoms that was significant (P < .005) after 1 hour. Relief lasted at least 6 hours after injection.


Journal of Pediatric Surgery | 1985

The effect of unilateral testicular torsion on the contralateral testicle in prepubertal Chinese hamsters

John A. Henderson; Paul Smey; Marc S. Cohen; Charles P. Davis; Andrew F. Payer; Terry A. Parkening; M Warren Michael

Recent studies of experimental testicular torsion in rats, rabbits, and guinea pigs have demonstrated conflicting evidence regarding contralateral testicular damage. Those studies in which cellular damage has been found are postulated to result from an immunological mechanism whereby the blood-testis barrier is disrupted with subsequent autoantibody formation. In this study, the histologic and immunologic effects of testicular torsion on the contrateral testicle were investigated in prepubertal Chinese hamsters. Four study groups were established; (1) Left orchiectomy only, (2) sham surgery (scrotal incision), (3) 720° left testicular torsion with left orchiectomy 24 hours later, (4) 720° torsion of left testicle with detorsion after 24 hours. The initial procedure was performed at 1 month of age with subsequent biopsies of the contralateral testicle at 1 week, 1 month, and 6 months after the initial procedure. Testicular tissue was examined for immunofluorescent activity using fluorescent labeled goat antihamster IgG. Positive controls were established by rabbit immunization (rabbit antihamster immunoglobulin) which was subsequently combined with fluorescent labeled goat antirabbit IgG. There was no appreciable difference in immunologic activity between control and experimental animals. Representative sections were examined histologically and no tubular damage was demonstrated and active spermatogenesis was noted at 6 months in all groups. We believe that our results support the premise that testicular torsion in the prepubertal period has no effect on the contralateral testicle.


The Journal of Urology | 1995

In Vivo Reduction of Bacterial Populations in the Urinary Tract of Catheterized Sheep by Iontophoresis

Charles P. Davis; M.E. Shirtliff; J.M. Scimeca; S.L. Hoskins; Michael M. Warren

PURPOSE Iontophoresis kills microbes in vitro and, therefore, may be a useful method for eliminating microbial populations associated with catheter-induced urinary tract infections in vivo. MATERIALS AND METHODS Catheters were modified to deliver current to platinum electrodes in the catheter tip. Female sheep were catheterized with this iontophoretic catheter and left ambulatory. In 5 sheep (experimental group) 400 microA was applied to the catheter and withheld in 4 sheep (control group) for 20 to 21 days. The animals were then sacrificed. During the study, types and concentrations of bacteria, and physical and chemical characteristics of the urine samples were determined. RESULTS Throughout the study, bacteria levels were reduced in urinary tracts of the experimental group (10(3) to 10(4) microbes per ml.) compared with the control group (10(7) microbes per ml.), without extensive alterations to urine chemistry or the sheep urinary tract. CONCLUSIONS Since iontophoresis safely reduced bacterial populations in catheterized sheep, this technology may reduce or eliminate nosocomial, catheter-induced urinary tract infections in humans.


The Journal of Urology | 1985

Urothelial Hyperplasia and Neoplasia. II. Detection of Nitrosamines and Interferon in Chronic Urinary Tract Infections in Rats

Charles P. Davis; Marc S. Cohen; Michael B. Gruber; Michael M. Warren

In rats with chronic urinary tract infections, urine and blood were examined for two classes of compounds (nitrosamines and interferon) which may lead to the development of urothelial hyperplasia and neoplasia. In vitro, Escherichia coli, a Proteus species or a mixture of both were able to induce high levels of interferon which theoretically could reduce the hosts cellular immune surveillance. These high levels were not detected in vivo in either short-term (5 hr. to 2 wk.) or long-term (2 wk. to 24 wk.) infected rats. In contrast, N, N dimethylnitrosamine was detected in the majority (greater than or equal to 50 per cent) of long term infected rats after 12 wk. although individual rats showed detectable levels as early as 2 wk. post infection. Sterile human or rat urine supported bacterial growth and subsequent production of N, N dimethylnitrosamine, but only after 16 wk. of subculturing in vitro. Gas chromatography was able to detect small amounts of nitrosamines extracted from urine. The mass spectrometer yielded quantitatively and qualitatively better detection. With long term infections, the appearance of a potential carcinogen, N, N dimethylnitrosamine, occurs in vivo and in vitro and correlates with previous findings that describe the development of hyperplastic and early neoplastic changes in the rat urothelium.


Annals of Emergency Medicine | 1993

Bungee jumper's foot drop peroneal nerve palsy caused by bungee cord jumping

Paul R Torre; Glenn G Williams; Thomas A. Blackwell; Charles P. Davis

Peroneal nerve injury is a common peripheral neuropathy from a variety of conditions and injuries. We encountered a case of peroneal nerve palsy in a professional bungee cord jumper. Review of the literature showed no previous report of this particular injury in bungee cord jumping.


The Journal of Urology | 1982

Klebsiella Pneumoniae-Induced Experimental Pyelitis: The Effect of Filiation on Infectivity

Robert C. Fader; Charles P. Davis

The effect of bacterial piliation on the infectivity of Klebsiella pneumoniae in the renal pelvis was examined by means of piliated and nonpiliated variants derived from a single parent strain. Piliated-phase variants were significantly more infective as determined by viable counts of bacteria isolated from the kidneys at the time of sacrifice. In addition, scanning electron microscope was used to examine the renal pelvis for evidence of infection. Kidneys infected with piliated-phase organisms exhibited greater tissue damage -- both in the magnitude of tissue alterations observed and in the number of kidneys affected. Thus, it is concluded that piliation contributes to the ability of K. pneumoniae to infect the renal pelvis following reflux from the bladder.

Collaboration


Dive into the Charles P. Davis's collaboration.

Top Co-Authors

Avatar

Michael M. Warren

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar

Marc S. Cohen

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar

Robert C. Fader

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Paul R Torre

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar

A S Goldman

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar

E A Weaver

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar

James A. Reinarz

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar

Margaret Thurmond-Anderle

University of Texas Medical Branch

View shared research outputs
Top Co-Authors

Avatar

Michael B. Gruber

University of Texas Medical Branch

View shared research outputs
Researchain Logo
Decentralizing Knowledge