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Biomedical subjects

J Lange

Publications and source records attributed to J Lange.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Hybrid reconstruction algorithm for x-ray computed tomography.

A hybrid reconstruction algorithm (HRA) is derived for fan beam geometry for use with systems utilizing a linear array of detectors. The algorithm uses fan beam geometry with a modified parallel beam reconstruction formula. The parallel beam algorithm is used with fan beam geometry by a simple geometric conversion and a different back projection formula. Correction for center of rotation shift is done during the back projection. Computer simulations are shown, both with the center of rotation shift uncorrected and corrected.

Algorithms↗
PubMedDate not supplied

137Cs dosimetry table for asymmetric source.

A common 137Cs brachytherapy source has a 2-cm physical length and 1.38-cm active length. The active length is not symmetric with respect to the source center because one source end contains an eyelet. Current dose rate tables assume a symmetric source loading with respect to the source center. A computer program was written to calculate an asymmetric distribution using the manufacturers' source specifications. Corrections were made for attenuation and obliquity through the source materials. Dose rate values in cGy/h for a 137Cs source equivalent to 1 mg of 226Ra are shown as a function of the radius from the source center and angle from the source end containing the eyelet. Dose rate values in the table were confirmed by ferrous sulfate measurements using small volumes. The table values agree with published values at points more distant than a few cm and lying at an angle such that the asymmetry of the source loading has its minimum influence.

Brachytherapy↗
PubMedDate not supplied

Primary neuroendocrine tumors of the cystic duct.

Primary neuroendocrine tumors of the cystic duct are extremely rare. Only 4 cases have been described to date. We report 2 patients in whom a primary neuroendocrine tumor of the cystic duct was incidentally detected during histological examination following cholecystectomy. With regard to the primary neuroendocrine tumor both patients were asymptomatic at the time of diagnosis. However, histologic examination did not confirm that the neuroendocrine tumors had been completely removed. Both patients underwent a second procedure. They are well after 47 and 49 months, respectively.

Bile Duct Neoplasms↗
PubMedDate not supplied

CytoView. A prototype computer image-based Papanicolaou smear proficiency test.

OBJECTIVE: To develop and assess CytoView, a prototype computer image-based cytology proficiency testing (PT) system, as an alternative to glass-slide cervical cytology PT. STUDY DESIGN: The computer-based PT consists of 10 cases taken from 10 Pap smears, each of which had received a consensus Clinical Laboratory Improvement Amendments-category diagnosis from three pathologists. Each CytoView "case" was the digital representation of > 8,000 microscopic fields, captured from a selected 5 x 10-mm rectangle of a Pap smear. The 5 x 10-mm capture rectangle was selected from the slide's most representative area for its diagnostic category. The CytoView project team developed each case through a multistep process that included image capture, image alignment, correlation of 10x and 40x images, and image display. The 10-slide CytoView PT prototype was then assessed by groups of cytopathologists and cytotechnologists. RESULTS: The CytoView prototype PT system was developed and assessed. CONCLUSION: Preliminary evaluation of CytoView indicated potential for this format as a valid and logistically feasible alternative to the traditional glass slide PT format.

Evaluation Studies as Topic↗
PubMedDate not supplied

Potassium reduces cerebral hemorrhage and death rate in hypertensive rats, even when blood pressure is not lowered.

In a study of the effects of K+ in stroke prone spontaneously hypertensive rats, adding K+ to normal chow was found to reduce the mortality from 83% to 2%, a 98% reduction. An 86% reduction in mortality occurred even when blood pressure was virtually equal in the two stroke prone spontaneously hypertensive groups being compared. Dietary K+ supplements also reduced mortality in hypertensive Dahl salt-sensitive rats from 55% to 4%, a 93% reduction. There was an 87% reduction in mortality even when blood pressure was equal in the Dahl salt-sensitive groups being compared. The added dietary K+ decreased blood pressure moderately in stroke prone spontaneously hypertensive rats and modestly in Dahl salt-sensitive rats, which probably contributed to the reduced death rate. More importantly, however, the added K+ seemed to prevent severe lesions in cerebral arteries and deaths even when blood pressure lowering was eliminated as a protective factor. In another group of stroke prone spontaneously hypertensive rats, there was a 40% incidence of cerebral hemorrhage in surviving rats not receiving K+ supplements and no incidence of cerebral hemorrhage in similar surviving rats receiving K+ supplements, which suggests that K+ supplements confer protection against brain hemorrhage.

Animals↗
PubMedDate not supplied

[Bilateral cancer of the kidney (author's transl)].

The simultaneous or successive occurrence of bilateral nephro-epithelioma in the adult is a possibility which is much rarer than that of the tumor in the child. The possibility of partial nephrectomy, carried out ex-vivo with renal auto-transplant should the occasion arise and that of total nephrectomy with allo-transplant brought up with their results.

Aged↗
PubMedDate not supplied

A structure-activity relationship study of the affinity of selected imidazo[1,2-a]pyridine derivatives, congeners of zolpidem, for the omega 1-subtype of the benzodiazepine receptor.

A series of 6-substituted 2-aryl-N,N-dimethylimidazol[1,2-a] pyridine-3-acetamides, congeners of zolpidem and alpidem, was synthesized and tested in vitro for binding with the benzodiazepine receptor in the competition with 3H-zolpidem as an omega 1-selective radioligand. Molecular electrostatic potential (MEP) and the HOMO and LUMO energies were calculated for the compounds by semi-empirical quantum chemistry methods. The lipophilicity parameter of the compounds, expressed as the logarithm of the octanol-water partition coefficient (log P), was calculated; alternatively, standard values of the Hansch hydrophobic substituent constants pi were used. In agreement with earlier investigations on the benzodiazepine receptor ligands with a high preference for the omega 1-subtype, a quantitative correlation of the biological data with molecular parameters has revealed a significant dependence (r = 0.954) of the binding affinity (IC50) on the deepest MEP minimum, in this case associated with the amide carbonyl oxygen atom. The lipophilicity parameters were found to be of lower significance.

Animals↗
PubMedDate not supplied

4(H)-1,2,4-triazole derivatives with expected biological activity.

Three isomeric 4-(carboxyphenyl)-3,5-diphenyl-1,2,4-triazoles (III) were prepared by condensation of bis(alpha-chlorobenzylidene)hydrazine (I) with ethyl aminobenzoate and subsequent alkaline hydrolysis of the ethyl esters (II) of III. III were also obtained by hydrolysis of the cyano compounds (IV) and by oxidation of the methyl derivatives (VI). A similar condensation of I with aminopyridines led to 4-pyridyl-3,5-diphenyl-1,2,4-triazoles (VII). Reduction of three isomeric 4-(nitrophenyl)-3,5-diphenyl-1,2,4-triazoles (X) (Fe/AcOH) gave the corresponding amino derivatives (XI). In the preparation of X, the method employing N-(nitrophenyl)-benzimidoyl chloride (VIII) and benzhydrazide (IX) proved to be most advantageous. Slight bacteriostatic activity of the triazoles prepared was observed in standard in vitro tests.

Acetylation↗
PubMedDate not supplied

4(H)-1,2,4-triazole derivatives with expected biological activity. Part IV. Synthesis of substituted 3,4,5-triaryl-1,2,4-triazoles.

A series of 23 3,4,5-triaryl-1,2,4-triazoles with various substituents in one, two, or all three aromatic rings were prepared for screening tests as potential antibacterial, mostly antituberculotic agents. The synthesis, depending on the nature and position of the substituents, was accomplished by one of the following methods; (A) condensation of symmetrically substituted bis(alpha-chlorobenzylidene)hydrazine with an aniline derivative; (B) reaction of an aniline derivative with a symmetrical diaroylhydrazine in the presence of PCL3; (C) direct condensation of aroylhydrazine with an appropriately substituted N-phenylbenzimidoyl chloride. The latter method was considered to be most advantageous; it warranted highest yield and purity of the products and made it possible to prepare triazoles with three different aryl groups.

Aniline Compounds↗
PubMedDate not supplied

A quantitative structure-activity relationship (QSAR) analysis of the effects of aromatic substitution on the anticonvulsant activity and toxicity of arylsuccinimides.

Anticonvulsant activity and toxicity of 20 arylsuccinimides were quantitatively correlated with the hydrophobic, electronic and steric parameters of the substituents in the benzene ring and at the nitrogen atom. The activity was highest when the benzene ring substituents X were characterized by hydrophobic fragmental constants fx lying in the 1.0-1.7 range, though toxicity increased with fx.

Animals↗
PubMedDate not supplied

[The effect of work-related stress on the occurrence of increased blood pressure].

In 546 officials the arterial blood pressure was measured twice at the beginning and at the end of a working day, filling also an inquiry form. As hypertension systolic BP over 160 mm Hg (21.3 kPa) or more, and diastolic BP 96 mm Hg (12.7 kPa) or more were accepted. In 90 subjects (16.5%) above normal pressure values were found. Hypertension had been diagnosed previously in 50 subjects in this group (55.5%) but only 13 of them (26%) were treated systematically. Excessive stress of work was complained of by 62.6% of the subjects. Increased blood pressure was found significantly more frequently in the group perceiving excessive stress of work (19.9%) as compared to those not experiencing this stress (10.8%, p less than 0.1). In the group in managerial posts these proportions were 24.8% and 14.4% respectively (p less than 0.1). Blood pressure rise to abnormal levels during the working day occurred also significantly more frequently in the group experiencing it this was noted only in 1.6% of cases (p less than 0.5). The knowledge of own hypertension was very low in this group. These results indicate the necessity of increasing prophylactic measures in the form of greater frequency of control measurements of the blood pressure, better health education, and limitation of stress situations in working environment.

Adult↗