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Biomedical subjects

M Fishbein

Publications and source records attributed to M Fishbein.

At least 19 recordsLinked to original sources

Menetrier's disease associated with formula protein allergy and small intestinal injury in an infant.

Menetrier's disease in infancy is extremely rare, and its natural course has not been studied in detail. The present case report describes an infant whose initial diagnosis was formula protein allergy and who developed gastric outlet obstruction by 3 months of age. The diagnosis of Menetrier's disease was suggested by characteristic radiological, pathological, and functional abnormalities of the stomach. Small intestinal partial villous atrophy, malabsorption, and protein loss from both the stomach and the intestine were documented. Cytomegalovirus infection was excluded. There was no evidence for an immune deficiency. The described features and an unrelenting course suggest that infantile Menetrier's disease may be an entity distinct from the childhood and adult forms.

Biopsy

A paradigm for restenosis based on cell biology: clues for the development of new preventive therapies.

Angioplasty causes substantial injury to the coronary artery intima and media that is unrecognizable by angiography. On the basis of a substantial body of research in oncology and wound healing, it is hypothesized that restenosis is a manifestation of the general wound healing response expressed specifically in vascular tissue. The temporal response to injury occurs in three characteristic phases: inflammation, granulation and extracellular matrix remodeling. The specific expression of these phases in the coronary artery leads to intimal hyperplasia at 1 to 4 months. The major milestones in the temporal sequence of restenosis are platelet aggregation, inflammatory cell infiltration, release of growth factors, medial smooth muscle cell modulation and proliferation, proteoglycan deposition and extracellular matrix remodeling. Each step has potential inhibitors that could be used for preventive therapy. Resolution of restenosis, however, probably requires both creation of the largest possible residual lumen and substantial inhibition of intimal hyperplasia.

Angioplasty, Balloon, Coronary

Excimer laser ablation of fibrocartilage: an in vitro and in vivo study.

To date, lasers have found only limited applications in orthopedics. We employed a 308 nm XeCl excimer laser for ablation of fibrocartilage, in order to investigate the feasibility of excimer laser assisted meniscectomy. Experiments were conducted both in vitro and in vivo. For the in vitro study, human menisci, obtained during surgery and autopsy, were irradiated via a 600 microns core fiber at radiant exposures ranging between 20 mj/mm2 and 80 mj/mm2, at 20 Hz. Ablation rate measurements and histological analysis of the samples were performed. The ablation rates were found to range from 3 microns/pulse to 100 microns/pulse depending on the radiant exposure and/or the applied pressure on the fiber delivery system. Thermographic analysis was also performed during pulsed excimer as well as CW Nd:Yag and CW CO2 laser irradiation. Temperatures were lower for excimer laser (Tmax less than 65 degrees) than CW ND: Yag (Tmax less than 210 degrees) or CW CO2 (Tmax less than 202 degrees) laser. For the in vitro study, medial meniscectomy was performed in 15 rabbits with the excimer laser and a CW Nd:Yag laser in the right and left knee respectively. Excimer laser irradiation was performed at 70 mj/mm2. Nd:Yag irradiation was performed via a 600 microns core fiber at power outputs between 20 to 40 W for 10 and 20 seconds duration. The healing response to injury was investigated by histological analysis of the menisci after 1 day, 1, 2, 4, and 8 weeks following the laser procedure. Excimer laser treated menisci showed less inflammatory reaction and noticeable repair with minimal inflammatory response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Pancreatic lymphangioma: CT, MRI, and angiographic features.

An unusual case of pancreatic lymphangioma presenting as a large mid-abdominal mass with sunburst pattern of calcification is herein described. The findings noted on computed tomography (CT), magnetic resonance imaging (MRI), and mesenteric angiography are illustrated.

Aged

XeCl excimer laser-induced fluorescence for selective ablation of atheromatous tissue.

In order to develop a reliable laser-induced fluorescence (LIF) guided laser angioplasty system, real time, pulse-by-pulse fluorescence spectra were recorded and the same fiberoptic was used for both detection of the fluorescence and for atheromatous tissue ablation. A 308 nm XeCl excimer laser served as the laser source for both the induction of fluorescence and the ablation. The fluorescence signal was induced at high laser energies during ablation without any serious change in the fluorescence pattern. A new characteristic fluorescence peak at 540 nm for atheromatous tissue was observed after treatment with chlortetracycline hydrochloride (CTC). This allowed the development of an algorithm and a subsequent index to discriminate the atheromatous tissue from the normal tissue. During atheromatous tissue ablation, this index changed as normal tissue was approached, thereby avoiding vessel perforation. Our results suggest that monitoring of this index through the catheter delivering the laser energy enhances selective ablation while simultaneously reducing the risk of vessel perforation.

Arteriosclerosis

Health and occupational correlates of perceived occupational stress in symphony orchestra musicians.

The authors examined the relationship between perceived occupational stress and the prevalence of a number of psychologic and physical ailments in a sample of professional symphony orchestra musicians and related musicians' self-reports of stress to demographic and occupational characteristics. Results of a survey of 2,212 musicians from 47 symphony orchestras revealed a significant relationship between perceived occupational stress and prevalence of a number of psychologic as well as physical medical problems. Age and occupational factors, such as the orchestra in which the musician plays, the instrument played, and status as a soloist, were also found to be significant correlates of perceived stress.

Adult

Pulsed ultraviolet lasers and the potential for safe laser angioplasty.

Endoscopic laser ablation of atheroma using continuous wave lasers is limited by imprecise control of thermal ablation, resulting in a crater that expands in width and depth, with thermal damage to adjacent normal tissue. We compared the gross and histologic effects of pulsed 308 mm excimer irradiation to continuous-wave Nd:YAG and Argon Ion laser irradiation, and pulsed 1,060 nm, 532 nm, 355 nm, and 266 nm laser irradiation in 205 atherosclerotic aortic segments. In contrast to the continuous-wave Nd: YAG, Argon Ion, and pulsed 1,060 nm, 532 nm, and 355 nm laser irradiation, which produced gross and histologic evidence of uncontrolled ablation, the 308 nm and 266 nm pulsed lasers induced incisions that conformed precisely to the beam configuration without gross evidence of thermal injury. The incision edges from these two lasers were histologically smooth and comparable to a scalpel incision. Our histologic findings suggest that rapid, precise endoscopic ablation of vascular and nonvascular tissue can be performed at these shorter pulsed wavelengths with very high precision with relatively little damage or risk to adjacent tissue.

Aorta, Abdominal

Laser ablation of human atherosclerotic plaque without adjacent tissue injury.

Seventy samples of human cadaver atherosclerotic aorta were irradiated in vitro using a 308 nm xenon chloride excimer laser. Energy per pulse, pulse duration and frequency were varied. For comparison, 60 segments were also irradiated with an argon ion and an Nd:YAG (neodymium:yttrium aluminum garnet) laser operated in the continuous mode. Tissue was fixed in formalin, sectioned and examined microscopically. The Nd:YAG and argon ion-irradiated tissue exhibited a central crater with irregular edges and concentric zones of thermal and blast injury. In contrast, the excimer laser-irradiated tissue had narrow deep incisions with minimal or no thermal injury. These preliminary experiments indicate that the excimer laser vaporizes tissue in a manner different from that of the continuous wave Nd:YAG or argon ion laser. The sharp incision margins and minimal damage to adjacent normal tissue suggest that the excimer laser is more desirable for general surgical and intravascular uses than are the conventionally used medical lasers.

Aorta

Methodology for recognition of invasive potential of Escherichia coli.

Surveillance for dysentery-related invasive potential in bacteria using the Sereny keratoconjunctivitis test is restricted by expense, time factor, and necessity for confirmation. Primary screening of isolates in a standardized mammalian cell culture system is recommended. Bacteria are grown 20 hr in veal infusion, washed, and resuspended in 20% heat-inactivated fetal bovine serum (FBS) supplemented with 0.12% brain heart infusion and 0.1% bile salts. The HeLa culture is grown 20 hr as a monolayer in chamber slides with 90% minimal essential medium (MEM)-10% FBS. The host culture is infected at a ratio of 10 bacteria/mammalian cell for 3 hr at 35 degrees C. The infection medium is replaced with MEM-FBS supplemented with 300 microng lysozyme and 5 microng gentamycin/ml. The infected monolayer is incubated 5 hr at 35 degrees C to permit intracellular multiplication. Specimens are washed, fixed with methanol, and stained successively with May-Grunwald and Giemsa dyes. Bacteria occur within the cytoplasm if invasion has occurred. The criterion for a positive test is that 1% of the host cells possesses at least 5 bacteria in 2 of 3 trials. Invasiveness is correlated with and possibly preconditioned by cytotoxic principle(s). Infectivity rates vary from 0 to 30%. The cytopathic effect is noted in 5-50% of HeLa cells. Positive results must be confirmed by the Sereny test.

Biological Assay

"Agenesis" of ductus arteriosus associated with the syndrome of tetralogy of Fallot and absent pulmonary valve.

Four infants with the severe form of the syndrome of tetralogy of Fallot and absent pulmonary valve are described. All had severe respiratory distress due to bronchial compression from massively dilated pulmonary arteries. The clinical diagnosis was confirmed by cardiac catheterization and angiocardiography. The infants died at age 3, 5, 30 and 90 days, respectively. Autopsy revealed, in addition to the usual components of the syndrome, absence of the ductus arteriosus or its remnants. The possible relation of "agenesis" of the ductus arteriosus to the pathogenesis of the severe form of this syndrome is discussed and pertinent studies are reviewed.

Cardiac Catheterization

Pathogenicity of Escherichia coli recovered from food.

In Western nations, pathogenic biotypes are sporadically encountered in foodborne gastroentetis. Cholera, dysentery, and chronic ulcerative colitis syndromes are recognized. E. coli has been associated on the average with 2% of annual food outbreaks and 5% of total cases. In developing nations, the incidence may be greater. In contrast with Salmonella and Shigella, significance can be assessed only by fulfillment of Koch's postulates. Preliminary studies using vascular permeability reaction for the detection of heart-labile toxin and the Sereny keratoconjunctivities test for demonstration of invasiveness indicate limited incidence of these pathogenicity markers in cultures from foods. Two per cent of isolates from cheeses involved in recent outbreaks were toxigenic; 14% were invasive. Corresponding values for food isolates not associated with illness were 10 and 0, respectively. To facilitate examination of multiple isolates, 10 may be pooled for the detection of heat-labile toxin, and 5 for invasiveness. Present model pathogenicity systems require standardization, estimation of specificity and sensitivity limits, examination by collaborative study, and ascertainment of human equivalence. Supplemental tests include capacity for colonization of intestinal epithelium and intracellular growth. Stereotypes based upon serology, host range, and recognized toxic factors may require modification.

Developing Countries

Microbiological methods. Methodology for enteropathogenic Escherichia coli.

Pathogenic biotypes of Escherichia coli grow poorly at temperatures greatly different from that of the host. Percentages quantitatively recovered at 42.0, 44.0, 44.5, and 45.5 degrees C in lauryl tryptose broth were 100, 76, 76, and 42, respectively. Corresponding values for 175 strains of varied origin were 98, 89, 82, and 65%. Maximal growth temperature is dependent upon medium. Lauryl tryptose and elevated coliform broths were equivalent in the recovery of small inocula (100 cells/ml) at 41.5-44.5 degrees. MacConkey, enteric enrichment, and Gram-negative broths were inhibitory at corresponding values. Growth at elevated temperature in nutrient broth is enhanced by carbohydrate. Standard lactose enrichment media fail to recover slow lactose fermenters. An acidified glutamic acid medium was unsuitable for recovery of E. coli. The data suggest modification of standard temperatures for the recovery of pathogenic biotypes. Previously recommended analytical methods have been simplified and supplemented. The enhancement of motility in indole-nitrite broth at 35 degrees C is recommended. A 4-tube semiquantitative test is offered for tentative identification of somatic and capsular antigens. Inclusion of Alkalescens-Dispar strains is warranted by their pathogenic behavior. Examination in Shigella and Alkalescens-Dispar sera is required to cover the dysentery-like biotypes. Pathogenic potential cannot be inferred from serotype.

Bacteriological Techniques