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Biomedical subjects

S Goldberg

Publications and source records attributed to S Goldberg.

At least 127 records · Page 7Linked to original sources
PubMed1990

Effect of cetylpyridinium chloride on microbial adhesion to hexadecane and polystyrene.

Microbial adhesion at the oil-water interface is a subject of both basic interest (e.g., as a technique for the measurement of hydrophobicity) and applied interest (e.g., for use in two-phase oil-water mouthwashes for the desorption of oral microorganisms). In general, surfactants inhibit microbial adhesion to oils and other hydrophobic surfaces. In the present study, we demonstrated that the cationic surfactant cetylpyridinium chloride (CPC) significantly enhanced microbial adhesion to hexadecane and various oils, as well as to the solid hydrophobic surface polystyrene. CPC increased adhesion to hexadecane of Escherichia coli, Candida albicans and Acinetobacter calcoaceticus MR-481 and of expectorated oral bacteria from near 0% to over 90%. The CPC concentration required for optimal enhancement of adhesion was a function of the initial cell density. This phenomenon was inhibited by high salt concentrations and, in the case of E. coli, by a low pH. CPC-pretreated cells were able to bind to hexadecane, but CPC-pretreated hexadecane was unable to bind untreated cells. Another cationic, surface-active antimicrobial agent, chlorhexidine gluconate, was similarly able to promote microbial adhesion to hexadecane. The results suggest that (i) CPC enhances microbial adhesion to hexadecane by binding via electrostatic interactions at the cell surface, thus diminishing surface charge and increasing cell surface hydrophobicity, and (ii) this phenomenon may have applications in oral formulations and in the use of hydrocarbon droplets as a support for cell immobilization.

Journal Article↗
PubMed1990

Mechanism of enhancement of microbial cell hydrophobicity by cationic polymers.

Polycationic polymers have been noted for their effects in promoting cell adhesion to various surfaces, but previous studies have failed to describe a mechanism dealing with this type of adhesion. In the present study, three polycationic polymers (chitosan, poly-L-lysine, and lysozyme) were tested for their effects on microbial hydrophobicity, as determined by adhesion to hydrocarbon and polystyrene. Test strains (Escherichia coli, Candida albicans, and a nonhydrophobic mutant, MR-481, derived from Acinetobacter calcoaceticus RAG-1) were vortexed with hexadecane in the presence of the various polycations, and the extent of adhesion was measured turbidimetrically. Adhesion of all three test strains rose from near zero values to over 90% in the presence of low concentrations of chitosan (125 to 250 micrograms/ml). Adhesion occurred by adsorption of chitosan directly to the cell surface, since E. coli cells preincubated in the presence of the polymer were highly adherent, whereas hexadecane droplets pretreated with chitosan were subsequently unable to bind untreated cells. Inorganic cations (Na+, Mg2+) inhibited the chitosan-mediated adhesion of E. coli to hexadecane, presumably by interfering with the electrostatic interactions responsible for adsorption of the polymer to the bacterial surface. Chitosan similarly promoted E. coli adhesion to polystyrene at concentrations slightly higher than those which mediated adhesion to hexadecane. Poly-L-lysine also promoted microbial adhesion to hexadecane, although at concentrations somewhat higher than those observed for chitosan. In order to study the effect of the cationic protein lysozyme, adhesion was studied at 0 degree C (to prevent enzymatic activity), using n-octane as the test hydrocarbon. Adhesion of E. coli increased by 70% in the presence of 80 micrograms of lysozyme per ml. When the negatively charged carboxylate residues on the E. coli cell surface were substituted for positively charged ammonium groups, the resulting cells became highly hydrophobic, even in the absence of polycations. The observed "hydrophobicity" of the microbial cells in the presence of polycations is thus probably due to a loss of surface electronegativity. The data suggest that enhancement of hydrophobicity by polycationic polymers is a general phenomenon.

Acinetobacter↗
PubMed1990

A controlled trial of corticosteroids to prevent restenosis after coronary angioplasty. M-HEART Group.

A multicenter, double-blind, placebo-controlled trial was conducted to determine if corticosteroids influence the development of restenosis after successful percutaneous transluminal coronary angioplasty (PTCA). Either placebo or 1.0 g methylprednisolone (steroid) was infused intravenously 2-24 hours before planned PTCA in 915 patients. The PTCA patient success rate was 87% (mean) in the eight centers. There were no differences in clinical or angiographic baseline variables between the two groups. End-point analysis (angiographic restenosis, death, recurrent ischemia necessitating early restudy, and coronary artery bypass graft surgery) showed that there was no significant difference comparing placebo- with steroid-treated patients. Angiographic restudy showed the lesion restenosis rate to be 39% (120 of 307 lesions) after placebo and 40% (117 of 291) after steroid treatment (p = NS). We conclude that pulse steroid pretreatment does not influence the overall restenosis rate after successful PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1990

Early diagnosed chronic illness and mother-child relationships in the first two years.

As part of a longitudinal study, children in three groups (healthy, n = 33; cystic fibrosis (CF) n = 28; congenital heart disease (CHD) n = 23) were seen between the ages of 12 and 18 months to assess infant-mother attachment and at two years to observe parent-child negotiation of autonomy/dependence in a puzzle task. Although the healthy group included the highest proportion of securely attached infants and the CHD group the lowest, the distribution of attachment patterns did not differ significantly between groups, or between any of the groups and established norms. At two years the healthy children had the most positive experience in the puzzle task while the children in the CF group had the least positive experience. When diagnostic groups were divided according to prior attachment status, the data for the healthy group were consistent with the prediction that securely attached children would have the most positive mother-child interaction at age two. This was not the case in either of the medically diagnosed groups. These data suggest that the influence of the early parent-child relationship may be altered by a child's health status. We may need different models to account for development in healthy and medically compromised children.

Adult↗
PubMed1990

Interactions of nimodipine and cocaine on endogenous catecholamines in the squirrel monkey.

The effects of nimodipine on the cocaine-induced alterations in blood pressure, heart rate, and plasma catecholamines were studied in the squirrel monkey. Cocaine in intravenously administered doses of 0.5, 1, and 2 mg/kg produced significant increases in blood pressure and significant decreases in heart rate. These cardiovascular changes were associated with transient episodes of arrhythmias and with significant increases in plasma concentrations of dopamine, epinephrine, and norepinephrine. Nimodipine, 1 micrograms/kg/min for 5 min administered intravenously 5 min after cocaine, corrects the cardiovascular and plasma catecholamine concentration changes induced by this alkaloid. The same dose of nimodipine administered 5 min before cocaine prevents elevations of blood pressure. Plasma catecholamine increments are also prevented except for the highest dose of cocaine. Cardiovascular changes induced by cocaine administration in the squirrel monkey are temporally associated with significant increments in plasma catecholamines. Administration of nimodipine prevents or minimizes these endocrine and physiologic changes.

Animals↗
PubMed1989

Surface electrocardiogram in the detection of transmural myocardial ischemia during coronary artery occlusion.

To examine whether coronary occlusion causing transmural ischemia was accurately reflected by ST-segment elevation on routine electrocardiograms, intracoronary and surface electrocardiograms were simultaneously recorded during percutaneous transluminal coronary angioplasty (PTCA). The study group consisted of 54 patients who had intracoronary ST-segment elevation during transient coronary occlusion (left anterior descending [LAD]: 25 patients, left circumflex [LC]: 19 patients, right coronary artery: 12 patients). Elevation of the ST segment on the surface electrocardiogram (greater than or equal to 0.1 mV) was recorded in 84% of patients during LAD dilatation, in 32% of patients during LC dilatation (p less than 0.01 vs LAD and right), and in 92% of patients during right coronary dilatation (not significant vs LAD). The magnitude of intracoronary ST elevation was 1.10 +/- 0.8, 1.68 +/- 1.2 and 0.8 +/- 0.6 mV for the LAD, LC and right occlusions, respectively (not significant). Thus, despite the comparable magnitude of intracoronary ST elevation, LC occlusion resulted in ST-segment elevation on the surface electrocardiogram in significantly fewer patients than did LAD or right occlusion. During LC occlusion, 9 patients had no electrocardiographic changes and 4 had only precordial ST depression. Thus, in patients with transmural ischemia during right or LAD occlusions, concordant ST elevation on the surface electrocardiogram is common. In contrast, ST-segment elevation is an insensitive marker of LC occlusion. In patients with ongoing ischemic symptoms and isolated precordial ST depression or no repolarization abnormalities, LC occlusion should be considered in the differential diagnosis.

Adult↗
PubMed1989

Myocardial salvage after regional beta-adrenergic blockade.

UNLABELLED: The aim of the study was to determine whether regional beta-adrenergic blockade via the coronary sinus limited myocardial damage after coronary artery occlusion in the canine model. Accordingly, open-chest anesthetized dogs were randomly allocated to one of three groups: a control group and groups treated with propranolol (in doses of 0.02, 0.2, and 2.0 mg/kg) given either intravenously or via the coronary sinus. The hypoperfused zone (i.e., risk area) and the extent of myocardial damage were assessed by autoradiography and triphenyltetrazolium chloride staining, respectively. Myocardial damage expressed as a percent of the hypoperfused zone was 84 +/- 5% in the control group (n = 9) and 78 +/- 7% (0.02 mg/kg, n = 7, NS), 63 +/- 6% (0.2 mg/kg, n = 7, p less than 0.05), and 62 +/- 7% (2.0 mg/kg, n = 9, p less than 0.02) in the groups receiving intravenous propranolol and 73 +/- 6% (0.02 mg/kg, n = 7, NS), 58 +/- 7% (0.2 mg/kg, n = 7, p less than 0.01), and 44 +/- 9% (2.0 mg/kg, n = 9, p less than 0.001) in groups receiving propranolol via the cardiac veins. There was a significant enhancement of myocardial salvage with increasing doses of propranolol delivered via the cardiac veins (linear regression trend, p less than 0.05). In contrast, myocardial damage expressed as a percent of the hypoperfused zone remained comparable with propranolol doses of 0.2 and 2.0 mg/kg administered intravenously (linear regression trend, NS). IN CONCLUSION: (1) regional beta-adrenergic blockade via the cardiac veins afforded significant myocardial salvage and (2) the regional administration of propranolol resulted in significant reduction of myocardial damage in a dose-dependent fashion.

Administration, Topical↗
PubMed1989

A study of post-orchiectomy surveillance in stage I testicular seminoma.

A study of post-orchiectomy surveillance without radiation therapy was done in patients with histologically pure seminoma apparently confined to the testicle. Criteria for study entry included a negative physical examination, chest x-ray, bipedal lymphogram, excretory urogram, abdomino-pelvic computerized tomography scan and serum alpha-fetoprotein. Followup consisted of frequent clinical examination, repeat lymphograms, abdominal computerized tomography scans, chest x-rays and serum markers. The purpose of this study was to determine the percentage of patients cured by orchiectomy alone, percentage who ultimately required therapy for occult metastases beyond the testicle, sites of relapse, factors predictive of relapse, and over-all cure rate and treatment morbidity. Of 81 patients followed for 3 to 43 months (median 19 months) only 3 had relapse at 3, 5 and 18 months after orchiectomy with nonbulky retroperitoneal disease: 1 patient had disease 17 months after salvage infradiaphragmatic radiation therapy, 1 had an increase in beta-human chorionic gonadotropin 11 months after radiation therapy, presumably due to occult nonseminoma, and he is receiving chemotherapy, and 1 has not yet completed treatment. Further followup is necessary to determine ultimate survival, since a risk for later relapse exists. However, to date it does not appear as if the outcome has been compromised when surveillance was applied in place of routine adjuvant radiotherapy.

Combined Modality Therapy↗
PubMed1989

Urinary output of urodiolenone in essential hypertension.

Increased amounts of urodiolenone, an isomer of a phytoalexin, were found in the urine of 34% of patients with essential hypertension. Urodiolenone was also excreted in 70% of patients with neurocirculatory asthenia (hyperkinetic syndrome) and labile hypertension; very small quantities were found in normal subjects. When grapefruit juice, which is rich in urodiolenone, was offered to hypertensive subjects, urodiolenone excretion was much higher than the amount ingested, indicating that output was not due to precursors present in the diet.

Adolescent↗
PubMed1989

Nuclear worries of Canadian youth: replication and extension.

A national survey of Canadian adolescents assessed concern, anxiety, and sources of information about the threat of nuclear war. Results indicated few geographical or gender differences in overall levels of concern, although females were more likely to admit fear and anxiety, and students with activist parents showed more concern. Family ranked below all media as a source of information.

Adolescent↗
PubMed1989

Interventional treatment in evolving myocardial infarction.

Residual myocardial function has been shown by many investigators to be a key factor in determining survival following acute myocardial infarction. In light of this, much effort has been undertaken to develop means of preserving myocardium in the setting of acute myocardial infarction. Acute revascularization has been approached as a logical method to reach this end. The development of more effective thrombolytic agents, better catheter dilatation systems, and improved surgical techniques have now made acute intervention possible, safe, and practical. Because of the marked clinical variability of patient presentation, as well as variability of available medical and surgical resources, a rational and logical system of approach must be developed, such that patients presenting with acute myocardial infarction can receive the most appropriate interventional therapy in any given setting.

Angioplasty, Balloon↗
PubMed1989

Atypical osteomyelitis of the skull base.

Most cases of osteomyelitis of the skull base occur as a result of inadequately treated localized malignant otitis externa. We present four patients with osteomyelitis of the skull base who did not present initially as malignant otitis externa. Increased morbidity may occur when these atypical cases are not promptly recognized and treated.

Adult↗
PubMed1989

Interventional therapy in acute myocardial infarction.

Large multicenter trials have shown an improvement in both survival and left ventricular function in patients undergoing reperfusion therapy in acute myocardial infarction. The most practical approach in treatment of patients with acute myocardial infarction involves intravenous administration of effective thrombolytic agents as soon as possible in the course of myocardial infarction. This approach using r-tPA results in reperfusion in approximately two-thirds of patients. In patients with contraindications to thrombolytic therapy and extensive injury current or hemodynamic compromise, emergent cardiac catheterization should be performed followed by immediate PTCA or bypass surgery. In patients who have already been treated with thrombolytic agents, controversy exists as to the optimal timing of cardiac catheterization to define coronary anatomy and the need for additional revascularization. We suggest that the most beneficial therapeutic strategy for the majority of patients is rapid administration of an effective intravenous thrombolytic agent combined with aspirin and heparin. Cardiac catheterization and PTCA or coronary artery bypass graft surgery may be deferred in stable patients. This approach is supported by evidence showing a lack of additional improvement in mortality and left ventricular function in patients treated with urgent PTCA. The advent of new therapeutic modalities in acute myocardial infarction, such as thrombolysis, has created a new subset of patients who either will have an improved prognosis if coronary artery reperfusion is completed or will have an increased risk for recurrent myocardial ischemia if definite revascularization is delayed.

Fibrinolytic Agents↗
PubMed1989

Continuities and discontinuities in the development of 64 very small premature infants to 4 years of age.

The psychiatric, psychological, school and overall family functioning of 64 very small premature infants was assessed from birth up to 48 mnths of age. Results indicated that 43% of infants scored in the abnormal range on a behaviour rating scale filled in by the mothers and 24% on a teacher rating scale at age 4. However, only 11% of the children received a psychiatric diagnosis. Traditional attachment ratings at 1 yr were not related to psychiatric status at age 4, but family functioning was. Disturbed children had also suffered more perinatal difficulties.

Brain Damage, Chronic↗