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Biomedical subjects

E Kahn

Publications and source records attributed to E Kahn.

At least 73 records · Page 4Linked to original sources
PubMed1991

Image registration and distortion correction in ion microscopy.

We present a method whereby the geometric registration of a series of ion microscopic images is performed by applying a two-step procedure. After applying a global linear transformation that corrects for geometric differences, a non-linear elastic transform is used in order to match local properties and structures of the images. Transformation parameters are computed on the basis of shape-specific points in the images. Distortion correction is achieved by relating ion images to the optical image of the same field and by using the two-step algorithm to register the images. This methodology is evaluated on synthetic misaligned objects and on thyroid tissue images.

Animals↗
PubMed1991

[Functional microscopic imaging of the thyroid gland with the help of analytical ion microscopy].

Secondary ion mass spectrometry (SIMS) microscopy provides a direct mapping of 127I in thyroid follicles. Thyroid tissue should be fixed and embedded in methacrylate resin, then cut in 3 microns-thick sections which are placed on a gold coverslip. The histological structure of the tissue is determined by the phosphorus ion (31P) which is present in large amounts in nuclei and phosphorylated molecules in the cytoplasm. An image processing system is used to superimpose images of 127I and 31P: this system allows measurement of local concentration of 127I in the follicular cell and follicular lumen compartments. A study in 8 subjects with normal thyroid glands showed that the level of 127I within follicular cells (430 +/- 250 micrograms/g; m +/- SE) was 6 to 7 times lower than the level in the follicular lumen (2.780 +/- 230 micrograms/g). In simple goiter (9 patients with macrofollicular adenomas), follicular lumen (346 +/- 17 micrograms/g) and cellular (68 +/- 6 micrograms/g) concentrations of 127I were decreased fivefold but the ratio of concentrations remained similar to that seen in normal tissue. In hyperfunctioning nodules (2 microfollicular and 3 macrofollicular adenomas), follicular cell and follicular lumen 127I levels varied widely and showed considerable overlap (2 to 16,000 micrograms/g and 1-21,000 micrograms/g, respectively). In benign cold nodules (1 microfollicular adenoma and 2 macrofollicular adenomas), follicular cell and follicular lumen 127I levels were barely detectable (3 +/- 0.6 micrograms/g and 6 +/- 0.7 micrograms/g respectively). In the 9 malignant nodules studied, no difference in 127I level profile was found with benign nodules.(ABSTRACT TRUNCATED AT 250 WORDS)

Goiter, Nodular↗
PubMed1991

Neuronal intestinal dysplasia: quantitative diagnostic criteria and clinical management.

Neuronal intestinal dysplasia (NID) clinically resembles Hirschsprung's disease but is characterized by hyperplasia rather than aganglionosis of the intramural plexus. Surgical intervention is common. We report the 5-year follow-up of an infant with the mixed form of NID managed medically and a method by which NID can be quantified histologically. Hyperganglionosis was determined by counting the number of ganglia per high-power field and the number of ganglion cells per ganglia from at least two biopsy specimens. The patient's biopsies and biopsies from "normal" and "inflamed" patients were compared. Normals contained 0.68 +/- 0.28 (mean +/- SD) ganglia per high-power field and 2.16 +/- 0.31 ganglion cells per ganglion. The inflamed biopsies were similar, 0.69 +/- 0.38 ganglia per high-power field and 2.63 +/- 0.40 ganglion cells per ganglion. The patient's initial rectal biopsy revealed 7.6 ganglia per high-power field and 3.8 ganglion cells per ganglion. Management of the patient included saline colonic irrigations and hyperalimentation with gradual reinstitution of breast-feeding. Clinical improvement was associated with normalization of manometry and biopsy findings, a phenomenon not documented previously in the literature. Irrigations were stopped at age 9 months, and the child is now asymptomatic.

Biopsy↗
PubMed1990

Lung scintigraphy clustering by texture analysis.

The efficiency of texture analysis parameters, describing the organization of grey level variations of an image, was studied for lung scintigraphic data classification. Twenty one patients received a 99mTc-MAA perfusion scan and 81mKr and 127Xe ventilation scans. Scans were scaled to 64 grey levels and 100 k events for inter subject comparison. The texture index was the average of the absolute difference between a pixel and its neighbors. Energy, entropy, correlation, local homogeneity and inertia were computed using co-occurrence matrices. A principal component analysis was carried out on each parameter for each type of scan and the first principal components were selected as clustering indices. Validation was achieved by simulating 2 series of 20 increasingly heterogeneous perfusion and ventilation scans. For most of the texture parameters, one principal component could summarize the patients data since it corresponded to the relative variances of 67%-88% for perfusion scans, 53%-99% for 81mKr scans and 38%-97% for 127Xe scans. The simulated series demonstrated a linear relationship between the heterogeneity and the first principal component for texture index, energy, entropy and inertia. This was not the case for correlation and local homogeneity. We conclude that heterogeneity of lung scans may be quantified by texture analysis. The texture index is the easiest to compute and provides the most efficient results for clinical purpose.

Humans↗
PubMed1990

Idiopathic arterial calcification of infancy: a case with prolonged survival.

We describe a patient with idiopathic arterial calcification of infancy and the following unusual features of the disease: (1) prolonged survival until age 11 years, (2) discordance between the extent of vascular calcification and clinical manifestations of arterial luminal occlusion, (3) a large area of myocardial calcification, (4) symptoms of cerebral-vascular insufficiency, and (5) spontaneous resolution of hypertension.

Calcinosis↗
PubMed1990

A crisis of community anxiety and mistrust: the Medfly eradication project in Santa Clara County, California, 1981-82.

Public anxiety of near panic proportions was created by the announcement of a plan to commence aerial application of malathion bait over a large urban area in California for the eradication of the Mediterranean fruit fly within four days. A risk assessment had reported the project entailed no significant risk to health but environmentalist groups and the media ignored the report. We describe the successful measures taken by State health workers to counteract the anxiety which itself constituted a serious public health problem. The most important measure was the rapid convening of a Health Advisory Committee composed of recognized experts and local professionals and leaders to provide an authoritative, respected and sympathetic voice to deal with the community's concerns. These experiences may be of value to other communities facing unwarranted anxiety over perceived environmental hazards.

Animals↗
PubMed1990

Digital correlation of ion and optical microscopic images: application to the study of thyroglobulin chemical modification.

A method has been developed in order to digitally correlate ion and optical microscopic images of the same sample areas. Serial cross-sections of human thyroid tissue were analyzed by secondary ion mass microscopy and by light microscopy. The resulting chemical and immunochemical map images were superimposed and correlated by means of a two-pass registration algorithm which allows to correct for geometrical distortions introduced by the ion microscope. Results are presented for the study of thyroglobulin chemical modification in pathological thyroid tissue that demonstrates heterogeneous molecular activity.

Humans↗
PubMed1989

Cholinesterase activity depression among California agricultural pesticide applicators.

Cholinesterase activity measurements for 542 California agricultural pesticide applicators under medical supervision during the first 9 months of 1985 were analyzed. Twenty-six workers, 4.8% of the sample, had cholinesterase values at or below the California threshold values for removal from continued exposure to cholinesterase-inhibiting pesticides (60% of baseline for red blood cell cholinesterase and 50% of baseline for plasma cholinesterase activity). Eight of these 26 workers, 31.5%, had pesticide-related illnesses. Pesticides most frequently associated with cholinesterase depressions exceeding California threshold values included mevinphos (Phosdrin), oxydemeton methyl (Metasystox-R), methomyl (Lannate), and acephate (Orthene); these pesticides included organophosphates in toxicity categories I and II and one carbamate in toxicity category I.

Agricultural Workers' Diseases↗
PubMed1989

Human ontogeny of the bile duct to portal space ratio.

Paucity of interlobular bile ducts is a common feature of cholestatic liver disease in premature infants. Whereas a bile duct to portal space ratio of 0.9 to 1.8 is cited by Alagille as the norm for children, there are no data regarding the normal bile duct to portal space ratio in preterm infants. In this study, by examining liver tissue obtained from autopsied fetuses and infants, we have determined that the bile duct to portal space ratio increases as a function of postconceptional age. After 38 weeks postconception, a ratio equal to or greater than 0.9 was seen in eight of nine subjects. Therefore, in evaluating premature infants for duct paucity, liver biopsies should be obtained only after 38 weeks. Prior to 38 weeks postconception, a bile duct to portal space ratio less than 0.9 may be physiologic.

Bile Ducts, Intrahepatic↗
PubMed1989

Epidermoid splenic cyst detected on a sports physical examination.

A 14-year-old female had a large, nontender abdominal mass on a routine sports physical examination. Following evaluation by ultrasound and computed tomography scan there was an initial attempt at drainage. The mass was subsequently removed. The diagnosis was epidermoid cyst of the spleen. In this report, we discuss the epidemiology and management of a splenic cyst, a rarely encountered diagnosis in adolescents, and emphasize the life-saving potential of the abdominal examination in sports medicine.

Adolescent↗
PubMed1989

A user-oriented software for cytological image analysis. Application to automatic DNA content measurement of thyroid cells.

More and more physicians and researchers in biology and image processing and analysis are using and developing methods which involve image analysing systems: image analysis permits replacement of qualitative subjective evaluation of cytological and histological specimens by quantitative methods. The purpose of our work was to provide a software which would fulfil constraints set by different users. This software is based on the following features: an automated cytology oriented architecture, a standard user interface and a selectable user mode. The system has been used to build a protocol for DNA content measurement on thyroid cells.

DNA, Neoplasm↗
PubMed1989

Protecting agricultural applicators from over-exposure to cholinesterase-inhibiting pesticides: perspectives from the California programme.

California's requirement for medical supervision of applicators regularly handling Toxicity Category I and II organophosphate and carbamate cholinesterase-inhibiting pesticides is examined from a policy perspective by the California Department of Health Services (CDHS). Changes to increase the effectiveness of medical supervision and solutions to a number of practical implementation problems are discussed, including the pesticides which should be monitored, the use of individual cholinesterase baselines, the enzymes to be measured, and the frequency of cholinesterase testing.

Agricultural Workers' Diseases↗
PubMed1989

Does proctosigmoiditis in inflammatory bowel disease presage the imminent onset of symptoms?

This study was undertaken to determine if asymptomatic children and adolescents with inflammatory bowel disease and moderate to severe anorectosigmoid inflammation might remain symptom-free for at least 12 months without specific intrarectal therapy. We prospectively studied 13 asymptomatic patients 6-21 years of age (four with Crohn's disease and nine with nonspecific colitis) with previously documented anorectosigmoid inflammation. Of these 13, four had moderate to severe anorectosigmoid inflammation both endoscopically and histologically. These four patients (two with Crohn's disease and two with nonspecific colitis) were entered into the second phase of the study. Three were receiving sulfasalazine, and one received methylprednisolone, 4 mg/day, and 6-mercaptopurine, 50 mg/day. None received intrarectal therapy. Clinical evaluation revealed that all four remained asymptomatic for 12 months despite the continued presence of moderate to severe anorectosigmoid inflammation. These results indicate that in children and adolescents with inflammatory bowel disease, the presence of inflammation of the anorectosigmoid does not necessarily correlate with or presage the onset of symptoms of proctosigmoiditis. Therefore, active inflammation of the anorectosigmoid is not the sole prerequisite for intrarectal therapy. The clinician should be guided by the symptoms of the patient, not by the presence or absence of active anorectosigmoid inflammation.

Adolescent↗
PubMed1989

Amyloidosis in children with inflammatory bowel disease.

Reactive systemic or secondary amyloidosis occurs in 1-29% of adults with Crohn's disease, but only sporadic cases of amyloidosis have been recognized in children with inflammatory bowel disease. We therefore have studied operative specimens (ileal, ileocolonic, and colonic) from 46 children (30 with Crohn's disease and 16 with ulcerative colitis) to determine the frequency of amyloid deposits. Sections of bowel, skin, and lymph nodes (n = 940) were stained by Congo red and examined by light microscopy and by polarized light. Amyloid deposits were found in only one of 46 subjects, an 18-year-old girl who had had Crohn's disease for 6 years. Intestinal amyloid deposits, present 16 months before the clinical diagnosis of amyloidosis, were patchy and seen predominantly in the intestinal mucosa. We conclude that amyloidosis is rare in children requiring surgery for Crohn's disease and ulcerative colitis. Examination of Congo red-stained sections can detect even subclinical amyloidosis. The amyloid deposits in our patient, which were both patchy and consistently mucosal, suggest that multiple endoscopic biopsy samples, not necessarily containing submucosa, are sufficient for diagnosis.

Adolescent↗