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Biomedical subjects

J Horton

Publications and source records attributed to J Horton.

At least 109 records · Page 6Linked to original sources
PubMed1991

Clinical evaluation of albendazole and praziquantel in the treatment of cerebral cysticercosis.

One hundred consecutive patients presenting with symptoms and signs of neurocysticercosis, confirmed by neuroimaging techniques were randomly assigned to treatment with either praziquantel 50 mg/kg/day for 15 days or albendazole 15 mg/kg/day for 30 days. All patients were treated also with steroids for 42 days. Follow-up was for 90 days for response to treatment and for at least 1 year for recurrence. Although similar numbers of patients showed no improvement in neuroimaging criteria at 3 months, the response to albendazole was more pronounced with larger numbers showing marked improvement or disappearance of lesions. Similar findings were apparent, with resolution of the presenting neurological signs and symptoms being more frequent, in the albendazole group. Electroencephalographic changes were also normalized. The use of steroids eliminated the frequently observed headache that has been seen during the first few days of treatment and permitted severe cases to be treated. Both albendazole and praziquantel appear to be effective at the doses used, with albendazole showing a slightly better overall response.

Adult↗
PubMed1989

Microdosimetry of a 42 MeV therapy neutron beam.

Radiation quality of fast neutron therapy beams can change with depth. For a neutron beam generated by p----Be, the primary effect is a "hardening" of the neutron beam produced by the scattering of slow neutron components. A 42 MeV neutron therapy beam was investigated using microdosimetric techniques. We report measurements of dose mean and saturation-corrected lineal energy in water phantom at build-up depth, 5, 15, and 30 cm, and show representative logarithmic dose distributions in lineal energy. RBE is also calculated using assumptions based on the Theory of Dual Radiation Action and presented as a function of dose and depth.

Humans↗
PubMed1989

Radiation Therapy Oncology Group (RTOG) survival data on anaplastic astrocytomas of the brain: does a more aggressive form of treatment adversely impact survival?

The RTOG has sponsored several studies for malignant gliomas of the brain that have included tumors classified as either glioblastoma multiforme (GBM) or anaplastic-atypical astrocytoma (AAF) under the Nelson schema. Glioblastoma multiforme, the more aggressive histology, has done poorly under all forms of treatment having a typical median survival of 8-11 months. The less common and less aggressive anaplastic-atypical astrocytoma seems to show a survival that worsens with treatment more aggressive than standard radiotherapy. All patients in this report have had their tumors centrally reviewed by a RTOG neuropathologist and have had the diagnosis of anaplastic-atypical astrocytoma confirmed. We compare three patient groups: standard photon radiotherapy from the 60 and 70 Gy arms of RTOG 74-01/ECOG 1374 and from the 65 Gy control arm of RTOG 76-11; radiation therapy and chemotherapy from RTOG 74-01/ECOG 1374 (60 Gy + BCNU and 60 Gy + MeCCNU + DTIC) and from RTOG 79-18 (60 Gy + BCNU); and photon irradiation plus a neutron boost from RTOG 76-11 and RTOG 80-07. There are 47 analyzable cases treated with photons alone, 78 analyzable cases treated with photons + chemotherapy, and 38 analyzable cases treated with photons + neutron boost. Median survival for the three groups of patients is, respectively, 3.0 years, 2.3 years, and 1.7 years. Actuarial survival curves are presented for each subgroup of patients and then for the patient subgroups further broken down by major prognostic variables--age and Karnofsky performance status. In each "better prognostic category," the median survival decreased as the "aggressiveness" of the treatment increased. The implications of these findings for future clinical trials is discussed.

Adolescent↗
PubMed1989

Topical and systemic antibiotics in the prevention of wound infection.

We evaluated under controlled conditions the efficacy of topical and systemic antibiotics, alone and in combination, in the prevention of wound infection and measured serum and tissue antibiotic levels in the wound and distant tissue after administration of antibiotics topically, systemically, and in combination. Adult Sprague-Dawley rats were contaminated on the dorsal paravertebral muscles with a preset standardized inoculum of Staphylococcus aureus, Escherichia coli, and Bacteroides fragilis. A second-generation cephalosporin was used; systemic administration was given intramuscularly and topically in powder form. Wound infection was confirmed by the recovery of the organism by culture. Prophylactic antibiotics were effective in preventing wound infection in all groups. Topical antibiotic and a combination (topical/systemic) antibiotic were significantly more effective than was systemic antibiotic alone in preventing wound infection. Adequate levels of antibiotic were achieved in serum and tissue with both topical and systemic antibiotics. Wound tissue concentration of antibiotic was significantly higher when topical antibiotic was used.

Administration, Topical↗
PubMed1989

Dimethyl-prostaglandin E2 prevents stress ulceration with minimal complications.

Gastric mucosal damage produced by topical application of necrotizing agents is diminished by topical or systemic pretreatment with a variety of E and F prostaglandins. The rat restraint model of gastric mucosal injury is more analogous to clinical stress ulceration than are models using intragastric application of toxic solutions; however, previous use of prostaglandin E1 in the restraint model resulted in a prohibitive incidence of GI morbidity. The current study used the restraint model of stress ulceration to compare the effects of a more potent prostaglandin analogue, 16,16-dimethyl prostaglandin E2, with hyperosmolar glucose and antacids. All three agents afforded significant protection from grossly apparent mucosal lesions, alone and in combination. Although other physiologic effects of each agent differed, the only effect which correlated with prevention of mucosal lesions was suppression of gastric acidity. Since effective doses of cytoprotective prostaglandins did not produce notable morbidity in comparison with other agents, they may prove to be a useful adjunct to stress ulcer prophylaxis in clinical settings.

16,16-Dimethylprostaglandin E2↗
PubMed1989

The cardiocirculatory and metabolic effects of endotoxin challenge after canine resuscitated hemorrhagic shock.

Although adequate volume resuscitation has decreased mortality from hemorrhagic shock, recovery in many patients is complicated by sepsis. To determine whether a subject debilitated by hemorrhagic shock would exhibit greater cardiocirculatory dysfunction when challenged with sepsis, ten dogs (Group I) were hemorrhaged to a mean arterial blood pressure of 30 mm Hg. After 2 hours of hypotension, shed blood and lactated Ringer's solution (50 ml/kg) were given, and the dogs were observed for 3 to 6 days. Ten dogs were sham hemorrhage and served as controls (Group II). On the experimental day, all cardiovascular and hemodynamic parameters were measured in both groups of animals before endotoxin challenge. There was no significant difference in cardiac output, stroke volume, stroke work, +dP/dt max, myocardial blood flow, myocardial oxygen metabolism, or acid-base balance in the two groups. Compared to sham-hemorrhaged dogs, resuscitated shock dogs had a significantly lower mean arterial blood pressure (127 +/- 7 vs. 110 +/- 6 mm Hg; p less than 0.05), and heart rate was significantly higher (86 +/- 6 vs. 109 +/- 7 beats/minute; p less than 0.05). Furthermore, maximal rate of left ventricular pressure fall (-dP/dT max) was significantly lower in the animals previously hemorrhaged, suggesting a persistent defect in left ventricular relaxation. Blood glucose and insulin levels were significantly elevated in the resuscitated shocked dogs, likely due to increased circulating catecholamine concentrations and enhanced glycogenolysis. Endotoxin shock caused significant hypotension, acidosis, and impaired regional perfusion in all dogs. In addition, cardiac output, stroke volume, dP/dT, and left ventricular end-diastolic pressure fell and hyperglycemia and hyperinsulinemia occurred in all dogs after endotoxin injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Do hospital personnel in hyperendemic areas require immunization against hepatitis B virus (HBV) infection? Is vertical transmission of HBV infection common in this group?

Medical personnel working in contact with blood and blood-contaminated body fluids are often considered to be a high-risk group for hepatitis B virus (HBV) infection and, as a result, it is recommended that they should be vaccinated against this infection. To find out if this is necessary in a country hyperendemic for HBV infection and to see if parents transmit the infection to their offspring, a total of 336 volunteer hospital employees, and 103 children of 47 of them, were tested for HBsAg, anti-HBc, anti-HBs, HBeAg and anti-HBe using the radioimmunoassay technique. Of these, 242 (72%) were found to have evidence of past or present HBV infection and only 94 (28%) had no such evidence. The infection prevalence in the 47 parents was 68% comparable to that of the total sample. Only 9 of their 103 children were positive for HBV markers. All tested parents of these positive children were either negative for all markers or positive for anti-HBs. The HBV infection prevalence among this hospital population is not different from that of the general Ethiopian population, and vertical transmission appears unlikely in this group. Therefore, mass vaccination of hospital staff in hyperendemic areas is unnecessary.

Adult↗
PubMed1988

Tamoxifen in advanced prostate cancer: an ECOG pilot study.

A group of 19 patients with advanced (Stage D) prostate cancer were treated with one of three dose levels of the anti-estrogen tamoxifen, 10 mg (3 patients), 20 mg (8 patients), or 30 mg (8 patients) daily. Five patients had received no prior systemic therapy. The treatment was tolerated well, but no objective responses occurred.

Cerebral Cortex↗
PubMed1988

Combined modality approach to treatment of malignant gliomas--re-evaluation of RTOG 7401/ECOG 1374 with long-term follow-up: a joint study of the Radiation Therapy Oncology Group and the Eastern Cooperative Oncology Group.

The Radiation Therapy Oncology Group (RTOG) and the Eastern Cooperative Oncology Group (ECOG) conducted a phase III trial in patients with malignant gliomas to evaluate 4 treatment arms: 1) 60 Gy to the whole brain; 2) 60 Gy plus 10-Gy boost; 3) 60 Gy plus carmustine (BCNU); and 4) 60 Gy plus semustine plus dacarbazine. Between September 1974 and March 1979, 626 patients with malignant gliomas were treated on protocol RTOG 7401/ECOG 1374. Each institution chose a subset of the treatments to which the patients would be randomized. Patients were stratified according to subset and randomized to the 4 treatment arms. There were no differences in survival among treatment arms. For patients greater than 60 years of age, the addition of chemotherapy to radiation therapy did not improve survival. For patients aged 40-60 years, there was a statistically significant increase in overall survival when BCNU was added to 60 Gy (P less than .01), with an increase in 2-year survival from 8% to 23%. This beneficial effect of BCNU is apparent in both histological groups (astrocytoma with atypical or anaplastic foci and glioblastoma multiforme). Although few confirmatory autopsies are available, long-term survival in patients with astrocytomas with atypical and anaplastic foci who were treated with 60 Gy plus BCNU (5-yr survival, 22%) suggests no significant late CNS toxicity, compared to 60 Gy alone (5-yr survival, 15%). This is confirmed by comparable neurological function in long-term survivors.

Adult↗
PubMed1987

Combination hormone therapy for metastatic breast cancer. An ECOG study of megestrol and aminoglutethimide.

This study was performed to determine the toxicity and effectiveness of megestrol acetate used with aminoglutethimide-hydrocortisone in the treatment of patients with metastatic breast cancer. Forty-five patients were treated, 29 of whom were fully eligible. Twelve of the 45 who had diabetes and/or hypertension were also analyzed. All had measurable sites of disease. The median age was 63 years, and the median time from first recurrence to on-study was 19 months. Approximately half the patients already had chemotherapy, and about 90% had hormone therapy for advanced disease. The most common side effects were skin rash, weight gain, hyperglycemia, and renal and neurologic problems. No life-threatening or lethal toxicities were reported. The overall response rate (complete or partial) among the fully eligible patients was 34% (90% confidence intervals from 20% to 51%), with a 5-month median duration of response. Patients with soft tissue, visceral, and osseous disease responded. Seventy-two percent of fully eligible patients have progressed or relapsed. The median time to failure of treatment was 6 months, and the median survival time was 15 months.

Adult↗
PubMed1986

Operative exposure and management of the petrous and upper cervical internal carotid artery.

The exposure and operative management of the petrous and upper cervical internal carotid artery (ICA) in 29 patients is detailed. Twenty-seven of these patients had extensive cranial base neoplasms (benign or malignant), 1 had an inflammatory cholesteatoma, and 1 had an aneurysm of the upper cervical ICA immediately proximal to the carotid canal. Preoperative studies useful in the evaluation of these patients included computed tomography, magnetic resonance imaging, cerebral and cervical angiography, and a balloon occlusion test of the ICA with evaluation of neurological status and of cerebral blood flow. The exposure of the upper cervical and petrous ICA was useful to obtain proximal control of the cavernous ICA, aided in the operative approach to extensive petroclival, intracavernous, and parapharyngeal neoplasms, and enabled the total resection of 23 of 27 such tumors. A subtemporal and preauricular infratemporal fossa approach was most commonly used for the exposure of the artery. Intraoperative arterial management consisted of exposure and decompression only, dissection from encasing neoplasm, resection of the invaded arterial segment and vein graft reconstruction, or intentional arterial occlusion. Vascular complications included 1 stroke due to delayed arterial occlusion, 1 stroke and death due to infection spreading from the nasopharynx with bilateral ICA rupture, and 1 pseudoaneurysm formation secondary to wound infection necessitating postoperative balloon occlusion of the ICA. Nonvascular complications included facial nerve paralysis in 10 patients (usually temporary), glossopharyngeal and vagal paralysis in 13 patients requiring Teflon injection of the vocal cord in 9, temporary difficulties with mastication in 9 patients, and wound infection in 3. The surgical exposure and management of the upper cervical and petrous ICA may permit a total operative resection of extensive cranial base neoplasms and is also an alternative for the management of vascular lesions involving these segments of the artery. With malignant neoplasms extending from the nasopharynx, postoperative infection remains a problem and may best be resolved by the use of a vascularized rectus abdominis muscle flap to reconstruct defects of the nasopharynx. Bilateral ICA encasement by neoplasms is also a major problem to be solved. The value of such an aggressive approach to the management of malignant neoplasms remains to be proven.

Carcinoma, Squamous Cell↗
PubMed1986

Education programs on smoking prevention and smoking cessation for students and housestaff in U.S. medical schools.

To determine the extent and characteristics of educational programs relating to smoking in U.S. medical schools, surveys of educational curricula were performed in 1983 and 1984. The first survey showed that 34% of medical schools had no course offerings on smoking for medical students, and very few addressed smoking prevention and smoking cessation. In the following year, the percentage of schools with curriculum courses on smoking prevention and smoking cessation had risen to 64% and 56%, respectively. Planned education programs for housestaff, however, were present in only 30% and 25% of medical school-affiliated programs. Only one housestaff program (5%) was present in the group of medical schools that had no educational programs on smoking prevention or cessation for its medical students. More emphasis on education regarding smoking prevention and smoking cessation in U.S. medical schools and in housestaff training programs is required.

Canada↗