Search PubMed⌕ Search

Biomedical subjects

M Friedman

Publications and source records attributed to M Friedman.

At least 55 records · Page 3Linked to original sources
PubMed2000

Cinnamaldehyde content in foods determined by gas chromatography-mass spectrometry.

trans-Cinnamaldehyde, the principal component of cinnamon flavor, is a potent antimicrobial compound present in essential oils such as cinnamon. In the course of studies designed to discover its maximum microbial lethality under food-processing conditions, a gas chromatographic-mass spectrophotometric procedure was developed for the extraction and analysis of essential oil components such as cinnamaldehyde from commercial cinnamon-containing foods (several brands of cinnamon breads, cereals, cookies, puddings, applesauces, and fruit juices). The cinnamaldehyde content ranged from trace amounts in orange juice to 12.2 mg/100 g (122 ppm) in apple cinnamon cereals and 31.1 mg/100 g (311 ppm) for cinnamon swirl bread (highest value). To ascertain the heat stability of cinnamaldehyde, pure cinnamaldehyde, pure eugenol, cinnamon oil, and mixtures consisting of cinnamaldehyde plus eugenol or cinnamon oil were heated at graded temperatures up to 210 degrees C and 60 min, and then possible compositional changes were examined. Eugenol was stable to heat, as were the components of cinnamon oil: carvone, eugenol, and linalool. In contrast, starting at approximately 60 degrees C, pure cinnamaldehyde undergoes a temperature-dependent transformation to benzaldehyde under the influence of heat. Eugenol, both pure and in cinnamon oil, when added to pure cinnamaldehyde protected the aldehyde against heat destruction. The protection may due to an antioxidative action of eugenol. The possible mechanism of this effect and the significance of these findings for food chemistry and microbiology are discussed.

Acrolein↗
PubMed2000

Effect of pH on the stability of plant phenolic compounds.

It is not uncommon to treat plant-derived foods and feeds with alkali. Such exposure to high pH is being used to recover proteins from cereals and legumes, to induce the formation of fiber-forming meat analogue vegetable protein, for preparing peeled fruits and vegetables, and for destroying microorganisms. In addition to their profound effects on functional and nutritional properties in such foods, such treatments may also cause other side reactions, including the destruction of natural polyphenolic compounds. Because plants contain a large number of structurally different antioxidant, anticarcinogenic, and antimicrobial polyphenolic compounds, it is of interest to know whether such compounds are stable to heat and to high pH. In this model study, the stability of the following natural polyphenols to pH in the range 3-11 was studied with the aid of ultraviolet spectroscopy: caffeic acid, (-)-catechin, chlorogenic acid, ferulic acid, gallic acid, (-)-epigallocatechin, rutin, and the nonphenolic compound trans-cinnamic acid. This study demonstrates that caffeic, chlorogenic, and gallic acids are not stable to high pH and that the pH- and time-dependent spectral transformations are not reversible. By contrast, chlorogenic acid is stable to acid pH, to heat, and to storage when added to apple juice. (-)-Catechin, (-)-epigallocatechin, ferulic acid, rutin, and trans-cinnamic acid resisted major pH-induced degradation. The results are rationalized in terms of relative resonance stabilization of phenoxide ions and quinone oxidation intermediates. The possible significance of these findings to food chemistry and microbiology is discussed.

Drug Stability↗
PubMed2000

Investigating the structure and properties of hydrated hydroxypropyl methylcellulose and egg albumin matrices containing carbamazepine: EPR and NMR study.

PURPOSE: The present study was conducted in order to investigate the correlation between the hydration properties of HPMC and EA matrices, gel microstructure and mobility, crystalline changes occurring in the gel and CBZ release kinetics. The influence of HPMC and EA erosion modes on CBZ release kinetics was interpreted in terms of gel microstructures. METHODS: NMR technique was used to determine the T1 and T2 relaxation rates of water in hydrated matrices. PFGSE NMR technique was employed to determine the SDC of water in the gels. EPR technique was used to determine the rotational correlation time of PCA in the hydrated matrices, gel microviscosity, mobile compartment, alpha, beta, gamma parameters and lorentzian/ gaussian ratio. These parameters are indicative of matrix microstructure. RESULTS: CBZ release mechanism from HPMC and EA matrices was markedly different. This behavior was related to the different structures of the polymer and protein. T2 relaxation studies and SDC measurements by NMR revealed higher chain hydration for HPMC compared to EA. Using the EPR technique it has been shown that the microviscosity and mobile compartment of matrices containing HPMC are lower than matrices containing EA. The microviscosity, mobile compartment and S-parameter values of hydrated matrices containing different EA/CBZ ratios were in correlation with the crystallization properties of CBZ in the gels, matrix erosion properties and CBZ release kinetics from the matrices. CONCLUSIONS: Characterization of matrix structures using EPR and NMR techniques supported our hypothesis concerning the mechanism involved in HPMC-CBZ interaction. EA/CBZ matrix microstructure features, analyzed by NMR and EPR techniques, were in correlation with the crystalline changes occurring in the gel and drug release kinetics.

Carbamazepine↗
PubMed2000

Synchronized release of sulpiride and sodium decanoate from HPMC matrices: a rational approach to enhance sulpiride absorption in the rat intestine.

PURPOSE: (a) To improve the absorption of sulpiride (SP) through the intestinal wall by incorporating it together with sodium decanoate (SD) into erodible matrices, designed to synchronize the release of SP and SD over different periods of time; (b) to test, in vivo the hypothesis that this simultaneous release increases SP absorption from the intestinal lumen. METHODS: Matrix tablets, possessing different erosion rates, were prepared by changing the ratios between SD and hydroxypropyl methylcellulose (HPMC). The amounts of HPMC varied from 2.5% to 17% w/w. Double layer tablets, containing similar amounts of SP, SD, and HPMC were used as nonsynchronous controls. The erosion kinetics of the tablets was assessed gravimetrically in vitro in USP basket dissolution apparatus and in vivo in the intestine of the anesthetized rat after intra-intestinal administration. SP absorption was studied after intra-intestinal administration of the different kinds of tablets to anesthetized rats, by monitoring SP blood levels. SP and SD levels in the withdrawn samples from the dissolution systems and blood were analyzed by HPLC. RESULTS: The controlled erosion of the tablets resulted in equal release rates of SP and SD during the initial linear phase of the process. This synchronized release lasted over different time periods depending on the relative amount of HPMC in the formulations (from 1 hour to 4 hours for 2.5 and 17 % w/w of HPMC, respectively). The synchronous matrices increased SP bioavailability after intra-intestinal administration. The increase varied from 1.4 to 2.3-fold for the slow and the fast release formulations, respectively (compared with the nonsynchronous, SD containing control formulations), indicating the ability to control both erosion rate and length of intestinal segment in which absorption is taking place. CONCLUSIONS: SP bioavailability after intestinal administration can be improved only if SP is released together with SD along the entire intestinal route. This can be accomplished by the design of synchronous matrices capable of concomitant release of SP and SD despite the differences in their water solubility. The ability to manipulate and control the duration of the synchronous phase of the matrices makes it possible for SP to be absorbed at different parts of the intestine.

Animals↗
PubMed2000

Pharmacodynamic effects of ketoprofen on crevicular fluid prostanoids in adult periodontitis.

The reported therapeutic benefits of nonsteroidal anti-inflammatory drugs (NSAIDs) in slowing periodontal disease progression appear intimately linked to the effective inhibition of local prostaglandin synthesis. This randomized, partially double-blind, controlled trial was conducted to evaluate the pharmacodynamic effects of the NSAID, ketoprofen (KTP), on gingival crevicular fluid (GCF) prostanoids. 42 subjects, ages 35-57 years, with moderate to advanced adult periodontitis were recruited and monitored for 22 days. On day 1, subjects were randomized for 1 of 5 treatments: i) 0.5% KTP gel; ii) 1.0% KTP gel; iii) 1.0% KTP alternate gel; iv) 2.0% KTP gel; v) 25 mg KTP capsule (positive control). Subjects applied 1 ml of gel topically to their gingiva or administered one capsule p.o., b.i.d. for 14.5 days. GCF samples were collected from posterior, interproximal sites on days 1 (pre-dosing; 1, 2, 3, 6 h), 8 (pre-dosing; 2 h), 15 (pre-dosing; 2 h) and 22 (post-treatment). GCF levels of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) were determined using RIA, and expressed in ng/ml and % reduction from baseline (%Effect). Neither a significant difference among groups nor a dose response in % effect for either prostanoid was evident, both overall and among cohorts with elevated baseline mediator levels ([PGE2]>34 ng/ml; [LTB4]>300 ng/ml). When data were combined from all groups, significant (p<0.01) % reductions in GCF PGE2 were noted at 1 and 2 h post-dosing (29% and 24% respectively). In comparing topical versus systemic formulations, all topical formulations were as equipotent as systemic dosing in altering local prostaglandin levels despite lower KTP exposures with gel treatments. These data indicate that both topical and systemic KTP therapies pharmacodynamically reduce GCF PGE2 levels in adult periodontitis subjects, allowing for potential inhibition of disease progression.

Administration, Topical↗
PubMed2000

Middle turbinate medialization and preservation in endoscopic sinus surgery.

OBJECTIVE/HYPOTHESIS: Lateral synechia formation between the middle turbinate (MT) and the lateral nasal wall is the most common complication of endoscopic sinus surgery. In an attempt to prevent this complication, a simple technique to preserve and medialize the MT was studied. METHODS: Five hundred patients underwent endoscopic sinus surgery with MT medialization and preservation. The caudal end of the MT and the opposing septal mucosa were abraded with a microdebrider for controlled synechia formation in an attempt to avoid lateralization of the MT. Follow-up ranged from 6 to 18 months, with a mean follow-up of 10 months. RESULTS: Ninety-three percent of the patients had successful MT medialization with a well-defined synechia between the septum and the MT. CONCLUSIONS: MT medialization with a microdebrider is simple, is reliable, and should be considered an alternative to turbinate resection or to other turbinate medialization techniques.

Adult↗
PubMed2000

Endoscopic sinus surgery in patients infected with HIV.

OBJECTIVES: To be able to plan appropriate surgical treatment for patients with HIV infection who have sinusitis refractory to medical therapy. DESIGN: We retrospectively reviewed the charts of 186 patients with HIV who required surgical treatment for sinusitis between 1987 and 1998. One hundred six charts provided the necessary information and an adequate follow-up to be included in the study. Collected data included preoperative and postoperative symptoms, radiographic staging, CD4 count at the time of surgery when available, and type and extent of surgery. RESULTS: Surgical treatment evolved over the 12 years from limited surgery to standard endoscopic sinus surgery (ESS). Eighteen patients had invasive fungal disease or complications of sinusitis requiring radical surgery. Thirty-six patients were treated with minimal procedures to address involved sinuses only. These patients were treated between 1987 and 1991. Recurrent disease or further complications occurred in 80.6% of the patients in this group. Since 1992, 52 patients were treated with standard ESS following the same indications for HIV- patients. This group had an improvement of symptoms in 75% of the cases, a rate comparable to the success rate in HIV- patients. CONCLUSIONS: HIV+ patients undergoing standard ESS enjoy a satisfactory success rate. HIV+ patients with surgical indication for endoscopic sinus surgery should be treated as non-HIV+ patients. Apparently, low CD4 count (< 100) does not serve as a contraindication for definitive surgery.

Adult↗
PubMed2000

Long-acting bronchodilation with once-daily dosing of tiotropium (Spiriva) in stable chronic obstructive pulmonary disease.

Tiotropium (Spiriva; Ba679BR) is a new-generation, long-acting anticholinergic bronchodilator that has muscarinic M(1) and M(3) receptor subtype selectivity. A multicenter, randomized, double-blind, parallel group, placebo-controlled study was conducted to evaluate the dose-response characteristics of tiotropium inhalation powder given once daily to stable patients with chronic obstructive pulmonary disease (COPD). Patients (mean FEV(1) = 1.08 L [42% predicted]) were randomized to receive 0, 4.5, 9, 18, or 36 microg tiotropium once daily at noon for 4 wk, with spirometry done before and hourly for 6 h after dosing. Patients measured and recorded their peak expiratory flow rates (PEFRs) three times each day. Significant dose-related improvement in FEV(1) and significant improvement in FVC occurred within 1 h after the first dose of tiotropium as compared with placebo. Over the 29 d of the study, all doses of tiotropium produced significant increases over placebo in trough (i.e., as measured spirometrically at 20 to 24 h after the previous dose and just before the next dose of tiotropium), peak, and 6-h postdose average FEV(1) and FVC, and in PEFR, without a significant difference among the different doses investigated. PEFR gradually returned to pretreatment baseline levels over a 3-wk evaluation period following the discontinuation of tiotropium. The overall safety profile for the tiotropium doses was similar to that for placebo. In summary, tiotropium was shown to be safe and effective in doses ranging from 4.5 to 36 microg delivered once daily. The improvements in spirometry with once-daily dosing confirm the long duration of action of tiotropium reported in single-dose studies, and its sustained improvement of spirometric measures over the 1 mo of testing in the study points to utility of tiotropium as a maintenance bronchodilator for patients with COPD. On the basis of the comparable bronchodilator response at doses from 9 to 36 microg, and advantages suggested by the safety profile at doses below 36 microg in this study, a dose of 18 microg once daily was selected for use in long-term studies of the safety and efficacy of tiotropium.

Administration, Inhalation↗
PubMed2000

Experience with percutaneous dilational tracheostomy.

Percutaneous dilational tracheostomy (PDT) has gained popularity among critical care specialists in the past 10 years. The initial studies in our specialty resulted in essentially banning the procedure as a dangerous substitute for standard operative tracheostomy. Despite this action, more than 1,100 cases of percutaneous tracheostomy have been reported with details on complications. We reviewed all published data and studied 311 patients of our own. A prospective study was performed in 3 groups of patients: 1) 50 patients scheduled for PDT performed in the operating room by a head and neck surgeon (group 1); 2) 50 patients who underwent standard operative tracheostomy performed by the same surgeon (group 2); and 3) 211 patients who underwent bedside PDT by critical care physicians (group 3). The intraoperative complication rates were 0% in group 1, 2% in group 2, and 4% in group 3; the postoperative complication rates were 13%, 4%, and 12%, respectively. There were 2 deaths in group 3, and none in groups 1 or 2. The statistically significant differences among the groups were the superiority of group I over group 3 in intraoperative complications, as well as the lower postoperative complication rate of the standard tracheostomy group. These results show that PDT can be performed with acceptable morbidity rates in relation to published complication rates of standard tracheostomy, but it has no advantage over standard tracheostomy with respect to postoperative morbidity. When they are performed by a head and neck surgeon, the morbidity associated with both standard and percutaneous tracheostomies can be reduced.

Adult↗
PubMed2000

Pharmacoeconomic evaluation of COPD.

STUDY OBJECTIVES: The clinical outcomes and health-care costs of a cohort of 413 patients with COPD are reported. DESIGN: This study was a retrospective pharmacoeconomic analysis. SETTING: University teaching hospital and affiliated clinics. PATIENTS: COPD patients with an FEV(1) < 65% of predicted and an FEV(1)/FVC ratio < 70% were eligible to be included in this analysis. INTERVENTIONS: Health-care resource utilization and costs were identified through chart review and were stratified according to the severity of COPD using the American Thoracic Society stages I, II, and III. The pharmacoeconomic analysis was a cost-of-illness evaluation that included the acquisition costs of initially prescribed pulmonary drugs, acquisition cost of pulmonary drugs added during the follow-up period, oxygen therapy, laboratory and diagnostic test costs, clinic visit costs, and emergency department and hospital costs. RESULTS: Total treatment cost was highly correlated with disease severity, with stage I COPD having the lowest cost ($1,681 per patient per year), stage III COPD having the highest cost ($10, 812 per patient per year), and stage II COPD having a cost intermediate to stage I and stage III ($5,037 per patient per year). With the exception of add-on drug acquisition cost, all cost variables were the highest in stage III COPD, the lowest in stage I COPD, and intermediate in stage II COPD. Hospitalization was the most important cost variable for all three stages of COPD severity. When stratified by both disease severity and initial bronchodilator drug selection, ipratropium alone in stage I COPD patients and the combination of ipratropium plus a ss-agonist (with or without steroid therapy) in stage II and stage III COPD patients had the lowest total costs. Reasons for the lower total cost of the ipratropium and ipratropium plus ss-agonist treatment groups included lower add-on drug costs, fewer diagnostic and laboratory tests, and a lower utilization rate for clinic visits, emergency department visits, and hospitalizations. CONCLUSIONS: Our study demonstrates a strong correlation between disease severity and total treatment cost in COPD. In addition, the type of bronchodilator therapy impacts total cost in COPD. In stage I COPD, ipratropium alone had the lowest total cost, while in stage II and stage III COPD, a combination of ipratropium plus a ss-agonist had the lowest total cost. These data support the concept that adherence to published treatment guidelines will result in lower health-care costs due to COPD.

Adult↗
PubMed2000

Modeling the epidemiology and economics of directly observed therapy in Baltimore.

SETTING: From 1958 to 1978, Baltimore maintained one of the highest pulmonary tuberculosis (TB) rates in the US. But, from 1978 to 1992 its TB rate declined by 64.3% and its ranking for TB fell from second highest among large US cites to twenty-eighth. This TB trend coincided with the implementation of an aggressive directly observed therapy (DOT) program by Baltimore's Health Department. OBJECTIVES: We used modeling to estimate the range of TB cases prevented in Baltimore under DOT. Case estimates equal the difference between the observed number of TB cases in Baltimore versus the expected number if Baltimore's TB trend was replaced by the TB trend for the US (low estimate) or the TB trend for all US cities with over 250,000 residents (high estimate). Economic savings are estimated. RESULTS: Without DOT we estimate there would have been between 1,577 (53.6%) and 2,233 (75.9%) more TB cases in Baltimore, costing $18.8 million to $27.1 million. Cases prevented and expenditures saved increased with increased DOT participation. CONCLUSION: Our model predicts that Baltimore's TB decline accompanying DOT resulted in health care savings equal to twice the city's total TB control budget for this period. These results are most plausibly due to DOT, since it was the only major change in Baltimore's TB control program, and rising TB risk factors-AIDS, injection drug use, poverty-in a city where TB had been epidemic should have triggered a TB increase as in comparable US cities, rather than the observed decline. As national TB rates continue to decline it will be important to identify ways to capture and reinvest these savings to support effective TB control programs.

Antitubercular Agents↗
PubMed2000

Achondroplasia in diverse Jewish and Arab populations in Israel: clinical and molecular characterization.

BACKGROUND: Achondroplasia is the most frequent form of disproportionate short stature, characterized by rhizomelic shortening of the limbs. This disorder is inherited as an autosomal dominant trait, although most of the cases are sporadic, a result of a de novo mutation. A recurrent glycine to arginine mutation at codon 380 (G380R) in the transmembrane domain of the fibroblast growth factor receptor 3 gene was found to cause achondroplasia among different populations. This is most uncommon in other autosomal dominant genetic diseases. OBJECTIVES: To determine whether this mutation is also common among Jewish patients from diverse ethnic groups and among the Arab population in Israel. METHODS: We examined the G380R mutation (G > A and G > C transition) and the mutation G375C (G > T transition at codon 375) in 31 sporadic patients and in one family diagnosed clinically to have achondroplasia. RESULTS: We found the G > A transition at codon 380 in 30 of our patients and the G > C transition in one patient. We were not able to detect any of the three mutations in two patients with an atypical form of achondroplasia. CONCLUSIONS: Our results further support the unusual observation that nucleotide 1138 of the FGFR3 gene is the most mutable nucleotide discovered to date across different populations.

Achondroplasia↗
PubMed2000

Primary epiploic appendagitis: an etiology of acute abdominal pain.

Primary epiploic appendagitis has a nonspecific clinical presentation but pathognomonic appearance on computerized tomography. We report a patient who was promptly diagnosed and treated with conservative management, and review the literature. This entity has not been well described in the general medical literature. Epiploic appendagitis should be considered in the differential diagnosis of atypical presentations of acute abdominal pain. Integration of a patient's history and physical exam with laboratory and computerized tomography findings allows a timely and confident diagnosis. Surgery is not necessary, but close follow-up is required.

Abdomen, Acute↗
PubMed1999

Two models for competition between age classes.

We consider two lumped age-structured models of juvenile against adult competition, one of which is a compartmental ordinary differential equation (ODE) model and one of which is a system of ODEs with delay derived from the McKendrick partial differential equation (PDE) model. Existence and stability of positive equilibria and existence of oscillatory solutions of both models are studied. Using a competition parameter, which measures the intra-specific competition, we investigate the effects of the competitive interactions between juveniles and adults on the dynamics of the population for both models. We find that these effects are different for the two models and discuss the differences from the modeling perspective. The discussion reveals an interesting relation between the length of the maturation period and the vital rates' dependence on the competition parameter.

Adult↗
PubMed1999

Left temporal lobe dysfunction in schizophrenia: event-related potential and behavioral evidence from phonetic and tonal dichotic listening tasks.

BACKGROUND: Asymmetric reduction of the P3 event-related potential (ERP) has provided evidence of left temporal lobe dysfunction in schizophrenia. Prior studies have been limited by reliance on simple target detection (oddball) tasks with pure tones. This study investigated the time course and topography of ERPs to binaural syllables or complex tones in dichotic listening tasks. METHODS: Event-related potentials of 26 patients meeting criteria for schizophrenia (n = 19) or schizoaffective disorder (n = 7) and 26 healthy controls were recorded from 30 scalp electrodes during 2 dichotic tasks in which different syllables or complex tones were simultaneously presented to each ear. A principal components analysis was used to derive factor scores corresponding to overlapping components in ERP waveforms--N1, N2, P3, and a late-positive potential. RESULTS: Healthy controls showed a right ear advantage for perceiving dichotic syllables, which was associated with greater N2 amplitude at left than right temporoparietal sites. Patients with schizophrenia did not show either this perceptual or N2 asymmetry. Patients also had smaller late-positive potential amplitude when compared with controls for both syllables and complex tones, with greatest decrement over left temporal sites. CONCLUSIONS: A right ear advantage in healthy adults for perceiving consonant-vowels was associated with a left-lateralized ERP component peaking at 200 milliseconds after syllable onset (N2). Patients with schizophrenia failed to show either of these task-dependent asymmetries, which may indicate a dysfunction of left temporal regions involved in phonetic classification. A task-independent asymmetric reduction of a later positive potential in patients with schizophrenia resembled left temporal P3 reductions reported for auditory oddball tasks.

Acoustic Stimulation↗