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Biomedical subjects

C Dixon

Publications and source records attributed to C Dixon.

At least 37 records · Page 2Linked to original sources
PubMed1998

Squamous cell carcinoma of the penis in a circumcised man: a case for dermatology and urology, and review of the literature.

Squamous cell carcinoma of the penis is most frequent in uncircumcised men. Other contributing factors include human papillomavirus infection, phimosis, balanitis, and smoking. We present a patient, circumcised at birth, who showed penile squamous cell carcinoma in situ and was treated with carbon dioxide laser ablation. Squamous cell carcinoma rarely presents in patients circumcised as infants. Factors contributing to chronic inflammation may predispose to this disease. Carbon dioxide and neodymium:YAG lasers are two modalities that are successful in the treatment of in situ and probably early invasive penile carcinoma. Optimal treatment includes coordination with a urologist if urethral disease is present.

Aged↗
PubMed1997

Sustainable urbanization in Vietnam.

"This paper examines the nature of [urban-based economic growth in Vietnam] and contends that the present size of Ho Chi Minh City and Hanoi are much greater than official figures suggest. It then goes on to review the situation with regard to urban poverty, basic needs and the environment to illustrate the extent to which this unacknowledged growth is not only threatening the sustained expansion of those cities, but also the sustainability of the economic growth on which the country is so reliant."

Asia↗
PubMed1997

Effect of terazosin on prostatism in men with normal and abnormal peak urinary flow rates.

OBJECTIVES: To determine if men with normal peak urinary flow rates (PFR) and prostatism respond to terazosin. METHODS: Forty-one men over the age of 50 years with an American Urological Association (AUA) symptom score greater than 8, postvoid residual urine volume (PVR) less than 300 mL, and no clinical or biochemical evidence of prostate cancer were treated with terazosin independent of the baseline PFR. The effect of terazosin on the AUA symptom score and PFR were compared for subjects with a PFR of 15 mL/s or less (group I) and those with a PFR greater than 15 mL/s (group II). RESULTS: The baseline age, AUA symptom score, prostate volume, and PVR were not significantly different between the two groups. The mean changes in AUA symptom score were -45.0% and -49.5% for groups I and II, respectively. The mean changes in PFR were 7.0% and -26.6% for groups I and II, respectively. CONCLUSIONS: The effect of terazosin on AUA symptom score is independent of baseline PFR, indicating that the mechanism of action of terazosin is not exclusively mediated by reduction of bladder outlet obstruction. Randomized controlled studies are required to confirm this provocative observation.

Adrenergic alpha-Antagonists↗
PubMed1997

Total prostate and transition zone volumes, and transition zone index are poorly correlated with objective measures of clinical benign prostatic hyperplasia.

PURPOSE: We determined if total prostate volume, transition zone volume or transition zone index is correlated with the severity of clinical benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A total of 93 men 52 to 85 years old, who were referred to a urology outpatient facility for treatment of clinical BPH, elevated serum prostate specific antigen or abnormal digital rectal examination, underwent measurement of total prostate and transition zone volume at transrectal ultrasonography. All men were requested to undergo uroflowmetry and complete the American Urological Association (AUA) symptom score. RESULTS: The pairwise correlations between AUA symptom score, versus total prostate and transition zone volumes and transition zone index were not statistically or clinically significant. A weak pairwise relationship was observed between peak flow rate versus total prostate volume (r2 = 0.160), transition zone volume (r2 = 0.156) and transition zone index (r2 = 0.147). The pairwise relationships between AUA symptom scores versus all prostate volumes were not statistically significant for subjects with mild (score 8 or less) or moderate to severe (score more than 8) symptoms. CONCLUSIONS: Total prostate and transition zone volumes, and transition zone index are not directly related to AUA symptom score and only weakly related to peak flow rate. These findings provide further evidence that the total prostate, total BPH and relative BPH volumes are not useful determinants of the severity of clinical BPH.

Aged↗
PubMed1997

The PartnerWeb Project: a component-based approach to enterprise-wide information integration and dissemination.

A component-based health information resource, delivered on an intranet and the Internet, utilizing World Wide Web (WWW) technology, has been built to meet the needs of a large integrated delivery network (IDN). Called PartnerWeb, this resource is intended to provide a variety of health care and reference information to both practitioners and consumers/patients. The initial target audience has been providers. Content management for the numerous departments, divisions, and other organizational entities within the IDN is accomplished by a distributed authoring and editing environment. Structured entry using a set of form tools into databases facilitates consistency of information presentation, while empowering designated authors and editors in the various entities to be responsible for their own materials, but not requiring them to be technically skilled. Each form tool manages an encapsulated component. The output of each component can be a dynamically generated display on WWW platforms, or an appropriate interface to other presentation environments. The PartnerWeb project lays the foundation for both an internal and external communication infrastructure for the enterprise that can facilitate information dissemination.

Computer Communication Networks↗
PubMed1996

Control of construction-associated nosocomial aspergillosis in an antiquated hematology unit.

OBJECTIVE: To determine the incidence of aspergillosis in patients with leukemia or bone marrow transplants during a construction-associated outbreak, and the effect of an environmental control program for Aspergillus. DESIGN: Clinical, microbiological, and pathological records were reviewed retrospectively once the outbreak was appreciated, and prospectively thereafter, to determine the presence or absence of aspergillosis and duration of neutropenia. SETTING: A university tertiary-care center with a single designated hematology-oncology unit. PATIENTS: From January 1988 to September 1993, there were 141 patients with leukemia or bone marrow transplants identified as being neutropenic during 231 admissions to this specialized unit. INTERVENTIONS: Installation of wall-mounted portable high-efficiency particulate air (HEPA)-filter air purifiers, application of copper-8-quinolinolate-formulated paint, replacement of perforated ceiling tiles with nonperforated type, sealing of all windows, replacement of horizontal, dust-accumulating blinds with vinyl, opaque, roller shades, and systematic and regular cleaning of surfaces. RESULTS: Thirty-six cases of nosocomial aspergillosis were diagnosed during this period. The incidence density (ID) in the preconstruction period was 3.18 per 1,000 days at risk. During construction activity-before the implementation of a control strategy-the ID increased dramatically to 9.88 per 1,000 days at risk. With infection control measures implemented and continued construction work, the ID decreased to 2.91 per 1,000 days at risk, comparable to the preconstruction baseline rate. CONCLUSIONS: An environmental control strategy incorporating widely available technology may have played an important role in controlling this outbreak of construction-associated invasive aspergillosis.

Air Pollution, Indoor↗
PubMed1995

Seven newly discovered intron positions in the triose-phosphate isomerase gene: evidence for the introns-late theory.

The gene encoding the glycolytic enzyme triose-phosphate isomerase (TPI; EC 5.3.1.1) has been central to the long-standing controversy on the origin and evolutionary significance of spliceosomal introns by virtue of its pivotal support for the introns-early view, or exon theory of genes. Putative correlations between intron positions and TPI protein structure have led to the conjecture that the gene was assembled by exon shuffling, and five TPI intron positions are old by the criterion of being conserved between animals and plants. We have sequenced TPI genes from three diverse eukaryotes--the basidiomycete Coprinus cinereus, the nematode Caenorhabditis elegans, and the insect Heliothis virescens--and have found introns at seven novel positions that disrupt previously recognized gene/protein structure correlations. The set of 21 TPI introns now known is consistent with a random model of intron insertion. Twelve of the 21 TPI introns appear to be of recent origin since each is present in but a single examined species. These results, together with their implication that as more TPI genes are sequenced more intron positions will be found, render TPI untenable as a paradigm for the introns-early theory and, instead, support the introns-late view that spliceosomal introns have been inserted into preexisting genes during eukaryotic evolution.

Amino Acid Sequence↗
PubMed1995

A prospective randomized comparison of transurethral resection to visual laser ablation of the prostate for the treatment of benign prostatic hyperplasia.

OBJECTIVES: Transurethral resection of the prostate (TURP) represents the accepted standard of surgical therapy for the management of symptomatic bladder outlet obstruction due to benign prostatic hyperplasia (BPH). However, this is a major operative procedure associated with significant perioperative morbidity. Visual laser ablation of the prostate (VLAP) utilizing a neodymium:yttrium-aluminum-garnet laser represents a new technologic approach to the surgical management of BPH. We compared the relative safety and efficacy of these two surgical approaches in a prospective, randomized trial. METHODS: At 6 investigational sites in the United States, 115 men with symptomatic BPH more than 50 years of age and not in retention, were randomly assigned to undergo either TURP (59 patients) of VLAP (56 patients). VLAP patients received a mean of 10,200 J of energy delivered in a mean of 5.5 intraprostate laser applications. At preoperative baseline, 3 months, 6 months, and 1 year postoperatively, all patients underwent clinical evaluations, including ultrasonic prostatic volume determination, standardized American Urological Association (AUA)-6 symptom score, peak urine flow, postvoid residual urine volume, and quality-of-life assessment. RESULTS: Compared to TURP, the VLAP procedure required less time (23.4 versus 45.2 minutes; P < 0.01) and shorter hospitalization (1.8 versus 3.1 days, P < 0.01). VLAP was associated with a significantly lower rate of serious treatment-related complications compared to TURP (10.7% versus 35.6%; P < 0.01). Only One (2.2%) patient undergoing VLAP experienced a greater than 2.2 g/dL decrease in hemoglobin compared to 40% of TURP patients (P = 0.01). No patient in the VLAP group required blood transfusion compared with 3.4% of those undergoing TURP. Of the 115 patients, clinical outcomes measured at 1 year showed a mean improvement in AUA-6 symptom scores of -9.0 for VLAP compared with -13.3 for TURP (P < 0.04), mean increase in peak urinary flow rate of 5.3 cc/s for VLAP compared with 7.0 cc/s for TURP (P = 0.27), and mean decrease in postvoid residual urine volume of -55.4 cc for VLAP compared with -138.8 cc for TURP (P < 0.01). At 1 year, 78.2% of patients undergoing VLAP indicated that their quality of life was improved compared with 93.0% of patients undergoing TURP (P = 0.03). When compared with TURP, treatment of BPH with VLAP is associated with less hemoglobin decrease, a lower likelihood of serious complication, and requires less procedure time and a shorter hospital stay. Through a 1-year follow-up, VLAP produced significant improvement over baseline in objective and subjective outcome measures. However, for 1-year improvement in AUA-6 symptom score, postvoid residual urine volume, and quality of life, VLAP was less effective than TURP. CONCLUSIONS: In this initial study in the United States, with relatively low-energy laser applications, VLAP did not result in as complete a removal of prostatic tissue as did TURP. Considering the lower morbidity, shorter procedure and hospitalization times, and the degree of effectiveness that was achieved even at the low-energy doses used in this study, VLAP appears to be a viable and safe alternative to standard TURP.

Aged↗
PubMed1994

Thoracoscopic use of laser in intractable pneumothorax.

A neodymium:yttrium, aluminum, garnet (Nd:YAG) laser was used via the instrumentation port of a standard thoracoscope for the sealing of air leaks, ablation of bullae, transection of adhesions and partial parietal pleurectomy in 13 patients with intractable pneumothorax. The mean duration of tube thoracostomy prior to treatment was 10 days (range 4 to 21 days). All patients had intractable air leakage. Three patients had chronic lung collapse of over 50% despite adequate chest drainage. All cases were treated with thoracoscopic laser. The source of air leakage was found to be ruptured bullae in 11 cases and a lung tear in 2 cases. In five cases the bullae were multiple. In 11 cases the air leakage stopped within 24 h of treatment, with a single self-limiting episode of recurrent air leakage. In two of the cases of chronic pneumothorax the lung failed to expand because of sizable bronchopleural fistulae. They required thoracotomy stapling of bullae and limited thoracoplasty. The mean duration of tube thoracostomy after thoracoscopic laser in the 11 successfully treated patients was 2.72 days (range 1 to 5 days). We conclude laser-assisted thoracoscopy is a useful therapeutic option when treating persistent air leakage. In most cases this method prevents prolonged periods of tube thoracostomy and obviates thoracotomy. In cases of chronic collapse of the lung with bronchopleural fistulae this technique may not be successful.

Adolescent↗
PubMed1994

The use of acyclovir in suspected encephalitis.

The early use of intravenous acyclovir in herpes simplex encephalitis (HSE) is essential. However, rapid diagnostic tests are not freely available. Hence, all patients with suspected encephalitis may need to be commenced on acyclovir. In our study, of 34 patients with suspected encephalitis, only two eventually had HSE confirmed, 19 had encephalitis not due to herpes simplex and in 13 a non-encephalitis illness was finally diagnosed. Guidelines for the use of acyclovir in suspected encephalitis are given aimed at minimizing the drug cost whilst still protecting all cases of presumed HSE.

Acyclovir↗
PubMed1993

New trends in the treatment of benign prostatic hyperplasia and carcinoma of the prostate.

Benign prostatic hyperplasia (BPH) is a very common condition affecting over 800,000 American males each year. A standard, effective, and well-proven therapy is prostatectomy. This surgical procedure is used to treat, in the United States, approximately 400,000 BPH patients annually. Major treatment benefit is expected in 70% to 80% of patients. Complications are seen in 20% of the surgically treated patients. Due to the advanced age of BPH patients and the presence of other serious coexisting medical problems, surgical therapy may be difficult to utilize. These patients, who present a high risk for surgery, are in need of alternative treatments. Alternative therapy in BPH patients with clinically important symptoms and signs of urinary outflow obstruction include treatment with pharmacological agents, balloon dilatation, laser beam therapy, transurethral thermal therapy, transrectal microwave hyperthermia, and transurethral microwave hyperthermia. These alternative treatment modalities are currently under intensive study. These new treatment modalities ultimately must be compared with the standard treatment, which is prostatectomy. Due to the unpredictable natural history of BPH, it is desirable that each Phase III study should contain a no-treatment observation-only arm. Adenocarcinoma of the prostate (CaP) has become a tumor, which first in frequency, and second in importance in cancer mortality statistics of American males. Local tumor control rates and long-term survivals, with radical prostatectomy or radiation therapy, have been excellent. There was, however, recent concern regarding a high incidence of microscopic local tumor recurrence following a definitive course of irradiation. Deep regional or intracavitary hyperthermia (HT) with phase steering may be of value as an adjuvant treatment to radiotherapy. This HT may increase the incidence of local tumor control obtained with radiotherapy. Phase I-II clinical studies are currently underway.

Adrenergic alpha-Antagonists↗
PubMed1992

Another view to blood and body substance precaution: 1988-91.

Occupational transmission of human immunodeficiency virus (HIV) in hospitals can be prevented with the use of 'blood and body substance precaution'. At the Royal Victoria Hospital, an infection control objective is to get employees automatically to use blood and body substance precaution with all patients--without relying on isolation signs. The concept of blood and body substance precaution was introduced in 1988 and simultaneously used with disease-specific signs. It was observed that disease-specific signs were mostly used to identify HIV-positive patients; this was verified under documented surveillance from July 7 to August 8, 1990, when 60 patients (14 HIV-positive and 46 whose HIV etiology was unknown) were observed. All 14 known HIV-positive patients were isolated with signs, while only four of 46 unknown HIV-positive patients (8.6%) had signs. The views of individual employees were subsequently studied via a questionnaire and results from this survey showed there was preference for isolating HIV-positive patients and identifying them with a sign.

Attitude of Health Personnel↗