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Biomedical subjects

M Friedman

Publications and source records attributed to M Friedman.

At least 271 records · Page 15Linked to original sources

Sustained-release delivery systems for treatment of dental diseases.

Sustained-release delivery systems allow the effective targeting of drugs for treating dental and periodontal diseases. Since dental diseases are chronic, the therapeutic agents used should persist in the oral cavity for as long as possible. Implanting fluoride, chlorhexidine, and other antiseptic agents embedded into sustained-release polymeric matrices into the oral cavity prevents cariogenic plaque accumulation. Both fibers and slab-like sustained-delivery devices bearing chemotherapeutic agents reduced periopathogenic bacteria levels associated with clinical improvement. This review provides useful background information for researchers seeking to develop controlled-release delivery systems for dental applications.

Animals↗

Release and absorption characteristics of novel theophylline sustained-release formulations: in vitro-in vivo correlation.

Five new experimental sustained-release (SR) formulations of theophylline, T-1, T-1-A, T-2, T-2-A, and T-2-E, in a matrix tablet form with a protein were developed. The in vitro release of theophylline from these novel experimental formulations and two commercial (Theotrim and Theo-Dur) SR formulations, was studied for 2 hr immersed in simulated gastric fluid TS, followed by an additional 10 hr immersed in simulated intestinal fluid TS. Like Therotrim and Theo-Dur, theophylline release profiles from all the novel experimental formulations were smooth, controlled, and unaffected by changes in the pH and the proteolytic enzyme content of the incubation media. Pharmacokinetic evaluation of T-1, T-1-A, T-2-A. Theotrim, and Theo-Dur was carried out in five dogs and six healthy human volunteers under fasting conditions, using immediate-release aminophylline tablets as controls. Pharmacokinetic analysis by the Wagner-Nelson procedure revealed sustained-release absorption characteristics for all the formulations with the exception of the immediate release aminophylline tablet. For each of the formulations tested, the regression analysis results of the percentage of theophylline absorbed in dogs or humans against the mean percentage released in vitro, at the corresponding times, indicated a high correlation. These data imply that the in vivo release profiles under fasting conditions in the gastrointestinal tract of dogs and humans may be similar to those in the in vitro studies.

Adult↗

Aggression and counteraggression during child psychiatric hospitalization.

The article reports on a 1-year descriptive study of aggressive incidents and staff counteraggressive strategies within a child psychiatry inpatient unit. Ninety-nine child/adolescent patients produced a total of 887 reportable aggressive incidents during the 12-month study period. Seclusion, activity restriction, physical restraint, and administration of p.r.n. medication were studied in relation to patient aggression. Results of the study confirm the hypotheses that (1) much patient aggression within defined clinical contexts conforms to patterns of prediction directly related to person and environmental variables, and (2) the primary value of counteraggression strategies such as seclusion and restraint resides in the acute management of aggressive children and not in long-term therapeutic functions. The article offers some recommendations for new research in this general area as well as suggestions for clinical applications of these methods.

Aggression↗

The effect of sustained release application of chlorhexidine on salivary levels of Streptococcus mutans in partial denture wearers.

The effect of a slow-releasing dosage (SRD) coating of chlorhexidine on the salivary levels of Streptococcus mutans and on plaque index scores in patients with removable partial dentures (RPD) was tested. The SRD proved to be effective in maintaining a low level of S. mutans counts after mechanical cleaning, as compared to a baseline established during the control period. Plaque index scores were lower following the treatment and correlated with the microbiological results. Our findings indicate that a single application of sustained-release chlorhexidine to removable partial dentures effectively maintains S. mutans levels as well as reducing the plaque score for a minimum period of 1 week.

Chlorhexidine↗

Sustained in vitro activity of human albumin microspheres containing chlorhexidine dihydrochloride against bacteria from cultures of organisms that cause urinary tract infections.

The potential of chlorhexidine dihydrochloride (CH HCl) incorporated into human albumin microspheres to provide sustained activity in vitro against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa from quality controls and from cultures of organisms that cause urinary tract infections was investigated. CH HCl was entrapped into five different formulations of human albumin microspheres. A technique was developed to evaluate the antibacterial activity of these microspheres and of controls (unloaded microspheres or gel). CH HCl microspheres exhibited antibacterial activity over a period of 16 days. Similar results were obtained with microspheres suspended in a methocel gel, and their antibacterial activity also continued for about 16 days. Empty microspheres or gel media alone were ineffective. The release rates of CH HCl from human albumin microspheres coated onto catheters by use of different gel formulations were also determined. The microsphere formulations were found to provide sustained antibacterial activity even at a low drug concentration.

Bacteria↗

Platysma myocutaneous flap for repair of hypopharyngeal strictures.

Hypopharyngeal strictures, either isolated or in conjunction with laryngeal and esophageal strictures, can occur following lye ingestion. Extensive stricture formation requires reconstruction to create a functional funnel system that empties below the cricoid. Esophageal replacement is not a substitute for adequate hypopharyngeal reconstruction. The pectoralis major muscle is often inadequate, because it yields too much bulk and often leads to continued aspiration. The platysma myocutaneous flap for hypopharyngeal reconstruction has not been previously reported. The inferiorly based platysma myocutaneous flap was used in two of our patients with lye burns, and bilateral superiorly based flaps were used in one. All are able to eat normally and have no significant stenosis. The platysma myocutaneous flap is a relatively simple and reliable alternative that is within the capability of every head and neck surgeon.

Adult↗

Rationale for elective neck dissection in 1990.

Elective neck dissection has long been a subject of debate among surgeons. The proponents of elective neck dissection base their rationale on studies that show a 30% incidence of occult disease in those situations for which elective neck dissection is recommended. One hundred eighty-two patients with advanced stages of squamous cell carcinoma of the head and neck were studied. All patients had preoperative computed tomography or magnetic resonance imaging, and all patients had some form of radical neck dissection. The sensitivity of clinical exam was compared with the sensitivity of computed tomography or magnetic resonance imaging in ability to detect nodal disease. The sensitivity of clinical exam alone was 71.7%, while the sensitivity of computed tomography or magnetic resonance imaging was 91.1%. Based on physical exam alone, there would be a 39% rate of occult disease; if computed tomography or magnetic resonance imaging data is combined with physical exam, the occult disease rate would drop to 12%. All centers performing elective neck dissection must reassess their rationale or restudy their occult disease rate with computed tomography or magnetic resonance imaging.

Carcinoma, Squamous Cell↗

The recommended food-buying principles of consumer educators: a behavioral science assessment of their feasibility for older consumers.

A content analysis recently identified twenty food-buying principles as the most commonly cited in consumer education textbooks of the 1980s. This study examines the behavior science literature in an effort to assess the ability of older consumers to practice these principles in American supermarkets. The study identifies three types of principles differing in the consumer behaviors they recommend as well as the nature and strength of the support they receive in the behavioral science literature. Implications of the study findings are drawn for gerontological research and educational practice.

Aged↗

A new degradable controlled release device for treatment of periodontal disease: in vitro release study.

The substantivity of a drug in the periodontal pocket is an important factor determining its effect on the subgingival flora. Therefore, one of the predominant factors in the development of a sustained release delivery device is the ability to control the rate of release of the drug. Previous studies have demonstrated the advantages of the local sustained release of chlorhexidine from nondegradable devices in the treatment of periodontal diseases. The aim of this study was to develop a degradable sustained release device composed of a cross-linked protein containing chlorhexidine as the therapeutic agent. The in vitro release profile of chlorhexidine from the degradable films was altered by the amount of chlorhexidine incorporated into the film, by the cross-link density of the polymer, and by the chlorhexidine salt used. The chlorhexidine in the final pharmaceutical preparation did not lose its antibacterial activity as was shown in an in vitro antibacterial test. This work demonstrates that the release of chlorhexidine from a degradable delivery system and the degradation of the matrix can be controlled by variation in the formulation. This presents a new dental drug delivery system that can be used as an adjunct in the treatment of periodontal diseases in the future. These studies enable us to choose the pharmaceutical formulations for clinical trials to be conducted testing the efficacy of this treatment modality.

Biodegradation, Environmental↗

The use of patients as student evaluators.

Current evaluation of medical students in their clinical clerkships is usually performed by their clinical tutors, and emphasizes knowledge, skills and behavior. However, it is not at all certain that the clinical tutors adequately appreciate the behavioral aspects of the student-patient interrelationship. Since these interactions are not directly observed by the tutors, their evaluation is based largely on second hand information. In the present study, patient opinion regarding student behavior was collected and compared to tutors' evaluation of the student. One hundred and eighty one patients and 31 clinical tutors evaluated 41 medical students during a 6 week internal medicine clerkship, using a specially designed patient questionnaire and tutors' rating form. An analysis of the correlation between tutors' individual rating parameters and the global score revealed high correlation for those parameters associated with clinical knowledge and skills, but lower correlations for parameters associated with students' relationship to patients. The study reveals difficulties associated with the evaluation of students by patients. The process is time-consuming, and introduces tension between students and patients. In addition the patients appeared to be poor discriminators in evaluating medical students. Finally, the study points out that tutors do not assign sufficient importance to the student-patient relationship in the global clerkship score.

Clinical Clerkship↗

Total versus subtotal thyroidectomy. Arguments, approaches, and recommendations.

Arguments for routine total thyroidectomy or routine, less than total resection have been espoused for treatment of well-differentiated intrathyroidal carcinoma. Numerous reports in the literature support either approach. No prospective randomized studies have been performed, partly because of the indolent nature of the disease. Many reports are also complicated by the failure of the authors to divide patients into high-risk and low-risk groups and to categorize and evaluate fully the histologic types of the resected tumors. Good evidence exists to show that in the majority of cases of intrathyroidal, well-differentiated lesions, bilateral subtotal resection yields results that compare favorably with total thyroidectomy. Logically, at least, a total thyroidectomy would seem to be preferable, because subtotal resection can be imprecise. Therefore, subtotal thyroidectomy can be recommended over total thyroidectomy, if only on the basis of comparison of complications. The type and rate of complications vary among surgeons. Each thyroid surgeon, therefore, must establish an individual complication rate. Total thyroidectomy in inexperienced hands is not recommended. We recommend, therefore, that total thyroidectomy be used selectively by surgeons who have the skill and experience necessary to make the decision intraoperatively. If, for example, during resection of the lobe that contains the primary tumor, the laryngeal nerves and parathyroid glands can be clearly identified and if there is minimal bleeding and trauma, the surgeon may proceed to side two to perform a total thyroidectomy. If the lesion is large, however, with distortion of anatomy, dissection may be difficult even for an experienced surgeon. Intracapsular parathyroids or undiscovered parathyroids on the side of initial resection should prompt the surgeon to perform a subtotal resection on side two. Under these circumstances, the surgeon should not feel that a total thyroidectomy justifies the increased risk. A unilateral resection, such as lobectomy plus isthmusectomy, can be performed with satisfactory long-term results in low-risk patients, that is, in those with small (less than 1.5 cm) unilateral intrathyroidal exposure and in those with no evidence of metastatic disease. Alternately, the AGES criteria of Hay et al can be used to identify patients in low- or high-risk groups. If the decision to perform a bilateral resection is based on the previous criteria, we recommend that a total thyroidectomy be performed only by an experienced surgeon. During surgery, if there is any suggestion that the laryngeal nerves or parathyroid glands would be at increased risk if a total resection were performed, it may be necessary to revert to a subtotal procedure.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗

Surgical management of thyroid carcinoma with laryngotracheal invasion.

Thyroid carcinoma that invades the airway can, in most cases, be treated by partial laryngectomy or partial tracheal resection. Total laryngectomy or circumferential tracheal reconstruction may be required in patients with extensive disease. Closure of subglottic and tracheal defects can be accomplished with the sternocleidomastoid myoperiosteal flap in a simple, single-staged procedure. Patterns of invasion and appropriate reconstruction are described.

Cricoid Cartilage↗

Unusual presentations of aortoiliac aneurysms.

Unusual presentations of aortoiliac aneurysms may be the reason for a delay in diagnosis of potentially life-threatening conditions. Five such unusual clinical pictures are presented and discussed. The aneurysms were falsely diagnosed as malignant disease, renal colic, sciatic syndrome, intra-abdominal bleeding of unknown origin, and psoas muscle abscess. The medical staff was misled by the atypical complaints, signs and symptoms, which resulted in a dangerous delay in diagnosis. The use of currently available ultrasonography and CAT scans, which enables early diagnosis, depends on the alertness of clinicians when they confront an atypical clinical picture that may be the first clue of a noninnocent aneurysm of the aortoiliac complex. Early surgical intervention before dissection, rupture or fistulization occur ensures a positive outcome and avoids emergency procedures with their attendant high operative mortality and postoperative morbidity.

Aged↗

Type A behavior: its diagnosis, cardiovascular relation and the effect of its modification on recurrence of coronary artery disease.

A general review of type A behavior and its possible relation to clinical coronary artery disease, hypertension and migraine is given. The humoral and lipid derangements initiated by type A behavior are described as well as the possible pathophysiologic phenomena this behavior effects leading to accentuation and hastening of the onset of clinical coronary artery disease. The correct method of diagnosing type A behavior as well as methods of diminishing its intensity both in the coronary and still symptomless person are described. The significant decline in coronary morbidity and mortality in patients with coronary artery disease given type A behavior counseling is described.

Behavior Therapy↗

In vitro binding of [14C]acrylamide to neurofilament and microtubule proteins of rats.

Acrylamide produces a dying back type of neuropathy in which there is an accumulation of neurofilaments in the axons. The in vitro binding of [14C]acrylamide to neurofilament and microtubule proteins obtained from rat spinal cord and brain was investigated. The relative binding to the high and middle molecular weight neurofilament was greater than to the low molecular weight neurofilament, while the rate of binding to MAP-1 (microtubule associated protein-1) and -2 was much greater than to tubulin. The binding rate to a 53 kDa protein which co-purified with the neurofilaments was between those of the middle and high molecular weight neurofilaments while the lowest rate of binding was to glial fibrillary acidic protein. These data indicate that there is a direct binding of acrylamide to cytoskeletal proteins.

Acrylamide↗

Esophageal stethoscope. Another possible cause of vocal cord paralysis.

Hoarseness after endotracheal intubation can result from compression of the anterior branch of the recurrent laryngeal nerve as it passes behind the thyroid cartilage to innervate the lateral cricoarytenoid muscle. This usually occurs when the cuff of the endotracheal tube lies in the larynx instead of the trachea. When a nasogastric tube is positioned in the midline, resultant postcricoid inflammation can result in vocal cord immobility. This may result from neuropraxia of the posterior branch of the recurrent laryngeal nerve that innervates the posterior cricoarytenoid and interarytenoid muscles, or inflammatory spasm of the interarytenoid muscles themselves. We present a case of vocal cord paralysis after general anesthesia that may have been caused by an esophageal stethoscope. The mechanism for vocal cord immobility could be similar to that of a midline nasogastric tube with resultant postcricoid inflammation. We describe measures that can be taken to prevent vocal cord paralysis after intubation of the larynx or esophagus.

Adult↗

High-performance liquid chromatography separation of phospholipid classes and arachidonic acid on cyanopropyl columns.

An HPLC method for the separation and analysis of arachidonic acid and eight phospholipid classes is described: phosphatidylglycerol, phosphatidylinositol, cardiolipin, phosphatidylserine, phosphatidylethanolamine, phosphatidylcholine, sphingomyelin, and 2-lysophosphatidylcholine. The separation is carried out at 60 degrees C on 2 cyanopropyl columns using a gradient of acetonitrile and 5 mM sodium acetate (pH 5.0). Cyanopropyl columns require a lower proportion of water in the mobile phase to elute the more polar phospholipids than other types of columns and are thus less prone to equilibration problems. The method is highly reproducible (average coefficient of variation for each retention time less than or equal to 3.5%) and permits analysis of peaks by phosphorus content. Data obtained by analyzing lipid extracts from rat alveolar macrophages prelabeled with [G-3H]-arachidonic acid were analyzed by this HPLC method and compared to standard analysis by TLC. There was a significant correlation between the radioactivity profiles obtained with the two chromatographic methods (HPLC versus TLC) by linear regression analysis [HPLC = 0.83 (TLC) + 3.58, n = 25, r = 0.95, P less than 0.001].

Animals↗