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Biomedical subjects

T Simon

Publications and source records attributed to T Simon.

At least 73 records · Page 4Linked to original sources

Complex issues for sexual assault peer education programs.

Peer education programs dealing with sexual assault are important for starting dialogue and improving students' awareness. If a peer education effort is to be effective, the college or university must have written policies condemning sexual assault, investigative and reporting procedures, and comprehensive sexual education and information programs. Experience at Brown University revealed the necessity of providing peer educators with opportunities during initial training for open and honest dialogue on the politics of campus rape, facing issues of power and dominance, women's dress as a factor in rape, and the distinction between victim and survivor. These discussions can be strained and frustrating, but they are a necessary step in resolving conflict among the peer educators and helping them provide a consistent message.

Female↗

Ruptured ovarian artery aneurysm complicating a term vaginal delivery.

Ruptured ovarian artery aneurysm is rare. Of the eight cases previously reported, seven were diagnosed postpartum. Our case of a ruptured right ovarian artery aneurysm was associated with massive retroperitoneal bleeding. The probable time of rupture could be traced to the second stage of labor. This case indicates the need for early evaluation of atypical flank pain during labor.

Adult↗

Active AIDS surveillance: hospital-based case finding in a metropolitan California county.

OBJECTIVES: Health departments that use passive surveillance alone cannot be sure of the level of complete and accurate reporting of acquired immunodeficiency syndrome (AIDS) cases. We sought to develop a model of active AIDS case reporting using limited county resources. METHODS: A validation study of AIDS case reporting using discharge diagnosis codes was undertaken to assess underreporting. Hospital-specific protocols for active surveillance were developed. RESULTS: The validation study revealed that 24% of AIDS cases in all hospitals were not reported through passive surveillance in 1990. In the first 3 months of 1991, active surveillance identified nine unreported cases (69% of the total cases reported) in one hospital. These underreporting estimates far exceed the 15% national underreporting rate estimated by the Centers for Disease Control. CONCLUSIONS: A method of hospital-based case finding was developed and serves as the model for implementing an ongoing program of active surveillance needed to ensure complete, accurate, and timely reporting of diagnosed AIDS cases. Application of this model may be helpful in attempts to minimize underreporting.

Acquired Immunodeficiency Syndrome↗

Colonic toxicity of administered medications and chemicals.

Although medication-induced colonotoxicity is uncommon, it is important that it be recognized, because the initial therapy for this condition is medication discontinuation. This review categorizes the association between the listed medications and colonotoxicity as "well-established" or "probable," according to the following criteria: number of clinical studies by independent clinical investigators, total number of reported cases, plausibility of an association based on experimental and pharmacologic studies, and validity of an association in each reported case. Medications associated with colonic ischemia include cocaine, ergotamine, estrogen, amphetamines, digitalis, methysergide, and vasopressin. Medications associated with colonic pseudoobstruction include narcotics, phenothiazines, vincristine, atropine or other anticholinergics, ganglionic blocking agents, and tricyclic antidepressants. Medications promoting infectious or necrotizing enterocolitis include numerous antibiotics associated with pseudomembranous colitis, deferoxamine associated with Yersinia enterocolitis, chemotherapy associated with neutropenic colitis, and hyperosmolar medications or formulas in infants. Medications associated with an allergic, inflammatory, or cytotoxic colitis include gold compounds, nonsteroidal antiinflammatory drugs, alpha-methyldopa, flucytosine, methotrexate, salicylates, and sulfasalazine. Potassium chloride, administered in slow-release wax matrices, can cause intestinal ulcers. Chronic cathartic use leads to colonic hypomotility and abdominal distention. Methysergide can cause a colonic stricture due to retroperitoneal fibrosis. Intrarectally administered compounds that have produced a toxic colitis include powerful acids, bases, and other corrosives. Enemas using hypertonic radiographic contrast agents have been associated with colitis in patients with colonic obstruction.

Colonic Diseases↗

Fulminant acute colitis following a self-administered hydrofluoric acid enema.

A 33-yr-old white male presented with bloody diarrhea, leukocytosis, and left lower quadrant direct and rebound tenderness after a self-administered concentrated hydrofluoric acid enema while intoxicated from intranasal cocaine administration. Intraoperative flexible sigmoidoscopy and a gastrografin enema revealed severe mucosal ulceration and edema in the rectum and sigmoid colon. Laparotomy revealed an ulcerated, necrotic, and purulent sigmoid colon and intraperitoneal pus. The patient underwent a limited sigmoid resection and a Hartman procedure. Five months later, the patient presented with a rectal stricture which was resected. This case demonstrates that a hydrofluoric acid enema can cause fulminant acute colitis and chronic colonic strictures.

Acute Disease↗

Physiological growth of arteries in the rat heart parallels the growth of capillaries, but not of myocytes.

Maladaption to hemodynamic overload, especially to arterial hypertension, has important clinical implications, and it is necessary to obtain criteria in order to discriminate physiological and pathological growth processes. We investigated the physiological growth of intramyocardial arteries in the rat heart. A new stereological method was introduced to determine the length of intramyocardial arteries from counts on histological sections. Four groups of male Sprague-Dawley rats of different ages were investigated. The growth rate of arteries was characterized by the growth coefficient b according to the exponential function y = axb (allometric growth function). Analysis of left ventricular weights (LVW) and total lengths of left ventricular intramyocardial arteries (L) revealed Lv = constant.LVW0.71 (r = 0.77, P < 0.001). The growth coefficient b < 1 indicates that the arterial supply of the heart, i.e. the length density of arteries Lv (length per unit myocardial volume), decreases during normal growth. Empirically, we found L = constant.LVW-0.28 (r = 0.43, P < 0.01). Previously, we estimated growth rates of b = 0.33 for the total length of left ventricular myocytes and b = 0.71 for the total length of capillaries. Thus, growth of intramyocardial arteries considerably exceeds the length increase of myocytes, but is proportional to the length increase of capillaries. Growth analysis of total mitochondrial volume using historical data of our group revealed proportionality to arteries, as well (b = 0.76). This indicates that growth of arteries and capillaries may be determined by oxygen consumption.

Animals↗

Hydrated clearance of gadolinium-DTPA as a measurement of glomerular filtration rate.

Technetium (99mTc)-diethylene triamine pentaacetic acid (DTPA) hydrated clearance studies are accurate for determining GFR but require special facilities for handling and measuring samples. We investigated the potential of a non-radioactive paramagnetic analog, Gadolinium (Gd)-diethylene triamine pentaacetic acid (DTPA), an approved NMR contrast agent, as a glomerular filtration marker. Instead of relying on the radioactivity of technetium, this test is based on the fact that gadolinium induces alterations in the NMR T1 relaxation times in blood and urine samples. Ninety patients underwent simultaneous determinations of GFR using 1 mCi of Tc-DTPA and 0.05 mmol/kg Gd-DTPA (Berlex Labs) IV. The patients were hydrated with oral and intravenous fluid. Following a one hour equilibrium period, three or four consecutive urine collections were obtained; plasma samples were acquired at the beginning and end of each approximately 20-minute interval. 99mTc-DTPA radioactivity was determined with a scintillation counter. T1 relaxation times were measured on a 10 MHz NMR spectrometer. These were converted to Gd-DTPA concentration by comparison with standard solutions. The Gd-DTPA derived GFR closely approximated the 99mTc-DTPA derived GFR which ranged from 15 to 147 ml/min. The equation and correlation coefficient of the regression line is y = 1.04 x -2.2, r = 0.94. Thus, Gd-DTPA is a safe, non-radioactive indicator of GFR that may provide an alternative renal clearance method for clinical studies of progressive renal disease and nephrotoxicity.

Contrast Media↗

Storage and transfusion of platelets collected by an automated two-stage apheresis procedure.

Platelets collected by using a two-stage automated blood cell separator were evaluated after 5 days of storage. The procedure caused no unanticipated physiologic changes in donors and produced greater than 3 x 10(11) intact platelets in 200 mL of plasma, plus an additional 400 mL of plasma with intact coagulation factors. Posttransfusion recovery of autologous radiolabeled platelets was comparable to that seen in platelets prepared by manual centrifugation techniques. Corrected count increments in 14 patients showed results similar to those with control transfusions. This device, which involves a collection time of less than 90 minutes, provides an option for platelet-pheresis in a variety of settings including blood mobiles.

Adult↗

Synergistic interaction of interferon-beta and interferon-gamma in coxsackievirus B3-infected carrier cultures of human myocardial fibroblasts.

The antiviral effects of human interferon-beta (IFN-beta) and human recombinant interferon-gamma (rIFN-gamma) were studied in persistently coxsackievirus B3-infected carrier cultures of human myocardial fibroblasts over a period of 21 days. Synergism was observed with concentrations as low as 30 IU of IFN-beta plus 10 IU of rIFN-gamma/mL, reducing mean viral titers from 6.0 x 10(7) to 1.3 x 10(4) pfu/mL and number of infected cells from 14.4% to 0.1% as determined by quantitative in situ hybridization. Higher concentrations of IFNs (both > or = 30 IU/mL) were associated with transient antagonism followed by antiviral synergism. With 100 IU of IFN-beta plus 30 IU of rIFN-gamma/mL, elimination of infectious virus was consistently achieved and sustained for 6 weeks after cessation of IFN application, whereas at least threefold higher concentrations were required with single drugs. In summary, our data support a concept of low-dose IFN combination schedules that might become useful in the treatment of enteroviral heart disease.

Cells, Cultured↗

A functional antibody mutant with an insertion in the framework region 3 loop of the VH domain: implications for antibody engineering.

We have studied the effects of a four residue insertion into the FR3 loop of the heavy chain variable region from the anti-NP antibody B1-8. The insertion mutant is obtained as secreted antibody without major defects in biosynthesis, indicating that antibody variable domains can accommodate length variation not only in complementarity determining regions (CDRs), but also in framework region (FR) loops. The B1-8 antigen binding site is not affected by the change in a neighbouring loop. FR3 insertions represent a new method of antibody engineering with a potential to obtain strong antigen binding by designing additional antigen contacting residues.

Amino Acid Sequence↗

Polymorphism of dextromethorphan metabolism: relationships between phenotype, genotype and response to the administration of encainide in humans.

The polymorphism of dextromethorphan and encainide metabolism is genetically determined and is related to the activity of hepatic CYP2D6. In order to examine the relations between CYP2D6 phenotype, genotype and the electrocardiographic response to the oral administration of encainide, 110 healthy subjects were studied. Metabolic ratios were calculated in urine after oral administration of 40 mg of dextromethorphan and in plasma obtained 2.5 h after oral administration of 50 mg of encainide. Encainide-induced electrocardiographic changes were measured 2.5 h after oral administration of the drug. Genotype was determined in 52 subjects. Results showed that phenotype, either extensive or poor metabolizer, for CYP2D6-dependent metabolism could be identified from the dextromethorphan metabolic ratio calculated in urine, from the encainide metabolic ratio calculated in plasma and from the genotype. However, despite the fact that the changes in atrioventricular (PR) and intraventricular (QRS) conduction times produced by encainide were different in extensive and poor metabolizer subjects and correlated with CYP2D6 activity, the electrocardiographic response was never 100% specific and sensitive for the identification of either phenotype. Moreover, genotypic identification of heterozygous and homozygous extensive metabolizer subjects did not predict CYP2D6 activity, as determined by dextromethorphan and encainide metabolic ratios, or encainide response, as determined by intraventricular and atrioventricular changes. Thus, CYP2D6 activity does not fully predict the electrocardiographic effects of encainide, and genotype, as determined in our study, cannot replace the determination of metabolic ratio in predicting CYP2D6 activity and encainide response in extensive metabolizer subjects.

Adult↗

[Establishment of reference values for fructosamine and HbA1c in childhood].

Reference values for fructosamine and glycated haemoglobin in children are still lacking. Using samples from 522 children (age range 1 day to 9 years), plasma electrophoresis was performed, fructosamine and total protein were determined in EDTA-plasma, and glucose and the fraction of glycated haemoglobin (HbA1c) were determined in EDTA blood. The results were grouped according to age (1, 3 and 5 days, 6-28 days, 2-12 months, 2-3 years, 4-6 years, and 7-9 years). Differences between the age groups were determined using the Mann-Whitney-U-test, and the values in each group were summarized where possible. The 95%-interval was calculated for fructosamine, protein-corrected fructosamine, and HbA1c.

Child↗

[Changes in the knowledge and attitude of physicians and health professionals in relation to AIDS during 1988-1990].

The authors interviewed in 1988, 570 and in 1990 425 health personnel about their knowledge and attitudes with AIDS. The results of 1990 survey shows: 63-76% of subjects changed their working habits, the increase rate to 1988 data is 30-40% and 11.7-18.0% changed their habits in their private life, the rate of increasing are: 8-9%. The safety gloves was mentioned by 82.1%-20% more than in 1988. 14% of the interviewed doctors and other health workers are refuse the care of an AIDS or a HIV positive patient, this rate is the double than was in 1988. Among the information resources the rate of postgraduate education was by 10% lower and 95% of the interviewed persons nominated the mass media as a main information channel in their knowledges about AIDS.

Acquired Immunodeficiency Syndrome↗

Expression of 1,25-dihydroxyvitamin D3 receptors in normal and psoriatic skin.

Increasing evidence suggests an immunoregulatory function of the potent steroid hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) which has been successfully applied for treatment of psoriasis. The skin is both a site of production and a target of 1,25(OH)2D3. In vitro, 1,25(OH)2D3 inhibits proliferation and stimulates differentiation of keratinocytes. We investigated the in situ expression of vitamin D-receptors (VDR) in normal and psoriatic skin by immunochemical methods. The VDR were visualized using the monoclonal antibody (MoAb) 9A7g to the VDR and the labeled avidinbiotin technique. Immunoreactivity was consistently confined to nuclei in all skin biopsies. In normal skin specimens (n = 10) VDR antigens were expressed in keratinocytes of all epidermal layers (except those of the stratum corneum) and in cells of the epidermal appendages. Double labeling experiments with MoAb to cluster-defined antigens indicated that melanocytes and approximately 75% of Langerhans cells exhibit 1,25(OH)2D3 receptors in normal skin biopsies (n = 5). Depending on their localization in skin compartments 42-62% of CD11b+ positive macrophages and 45-75% of CD3+ T lymphocytes expressed VDR. Non-lesional psoriatic skin specimens (n = 8) revealed nearly identical staining patterns. Lesional psoriatic skin specimens (n = 8) exhibited a significant increase of VDR expression both in basal and suprabasal epidermal layers as measured by computer-assisted morphometry and showed a remarkable change of the immune cell pattern: the densitity and proportion of VDR positive T lymphocytes and macrophages were higher in the epidermal and the perivascular papillary loop compartment. These in vivo findings strongly support the hypothesis that 1,25(OH)2D3 modulates immune response and cell proliferation/differentiation in human skin.

Adult↗

Antibody domain mutants demonstrate autonomy of the antigen binding site.

We have constructed derivatives of a lambda I light chain-bearing anti-(4-hydroxy,3-nitrophenyl)acetyl (NP) antibody which have the V regions exchanged between heavy chains and light chains of the kappa or lambda I type. These antibodies are assembled and secreted normally, and bind haptenic and macromolecular ligands like the wild-type; similar results are obtained for monovalent heterodimers of VHCL and lambda I light chains. The observed independence of the binding site from the constant region context argues against a role of longitudinal interactions between constant and variable domains in antigen recognition, and therefore against cooperativity between binding sites.

Animals↗