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Biomedical subjects

G Cohen

Publications and source records attributed to G Cohen.

531 records · Page 30Linked to original sources
PubMedDate not supplied

Computer-assisted diagnosis of strabismus.

A program for use on a microcomputer was developed to assist in the diagnosis of strabismus. The matrix consists of 41 separate disorders and 59 facts (history and examination findings). The facts are answered in a yes/no format. The relationship between the fact and the disorder is weighted as to whether the fact is always present, usually present, sometimes present, not related, unlikely to be present, not usually present, or never present. The computer makes the diagnosis (or diagnoses) indicating the most likely disorder when several are possible from the information given. Over 300 patient files were tested with the program. Of the last 50 records reviewed (70 disorders), the computer diagnosis agreed with the clinical diagnosis in 91% of the cases. Continued refinement of the program should be able to improve this accuracy.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

Intraoperative conformal optimization for transperineal prostate implantation using magnetic resonance spectroscopic imaging.

PURPOSE: Recent studies have demonstrated that magnetic resonance spectroscopic imaging (MRSI) of the prostate may effectively distinguish between regions of cancer and normal prostatic epithelium. This diagnostic imaging tool takes advantage of the increased choline and creatine versus citrate ratio found in malignant, compared with normal, prostate tissue. The purpose of this report is to present our initial experience integrating MRSI data into an intraoperative computer-based optimization planning system for prostate cancer patients who underwent permanent interstitial I 125 implantation. The goal of this approach was to achieve dose escalation to intraprostatic tumor deposits on the basis of MRSI findings without exceeding the tolerance of adjacent normal tissue structures. MATERIALS AND METHODS: MRSI was obtained before surgery for four consecutive patients with clinically localized prostate cancer. The ratios of choline and citrate for the prostate were analyzed, and regions in which malignant cells were suspected to be present were identified. These ratios were calculated on a spatial grid overlying the axial MRSI of the prostate. MRSI coordinates containing these suspicious regions were registered to the intraoperative ultrasound images. A computer-based treatment planning system, which relied on a genetic algorithm, was used to determine the optimal seed distribution necessary to achieve maximal target volume coverage with the prescription dose and to maintain urethra and rectal doses within tolerance ranges. The treatment planning system was specifically designed to escalate the dose to MRS-positive voxels while at the same time achieving preferential sparing of surrounding normal tissues. Patients underwent transperineal interstitial implantation with I 125 by use of this intraoperatively generated plan. Postimplant computed tomographic scans were performed on the same day of the procedure in all cases, and dosimetric guidelines of the American Brachytherapy Society were used to assess implant quality. RESULTS: Based on the postimplant computed tomographic evaluation, the intraoperative optimization treatment planning program was able to achieve a minimum dose of 139% to 192% of the 144-Gy prescription dose to the MRS-positive voxels. The percentage of the prostate volume receiving 100% of the prescription dose ranged from 92% to 97%, and the dose delivered to 90% of the target for the target volume ranged from 96% to 124%. Despite the dose escalation achieved for the positive voxels, the urethral and rectal doses were maintained within tolerance ranges. The average and maximal rectal doses ranged from 28% to 43% and 69% to 115% of the prescription dose, respectively. The average and maximal urethral doses ranged from 66% to 144% and 118% to 166% of the prescription dose, respectively. CONCLUSIONS: Using this brachytherapy optimization system, we could demonstrate the feasibility of MRS-optimized dose distributions for I 125 permanent prostate implants. This approach may have an impact on the ability to select regions within the prostate to safely employ dose escalation for patients treated with permanent interstitial implantation and to improve outcome for patients with organ-confined prostatic cancers.

Aged↗
PubMedDate not supplied

The efficiency of switching from infliximab to etanercept and vice-versa in patients with rheumatoid arthritis.

OBJECTIVE: To determine whether it may be successful to try another TNF-alpha antagonist (infliximab or etanercept) when one has failed due to non response or the development of side effects. METHODS: In a cohort of 282 patients with rheumatoid arthritis treated with infliximab or etanercept, we observed 38 patients who had received both agents. RESULTS: Twenty-four patients received infliximab first and 14 received etanercept first. Discontinuation was due to a lack of efficiency for 29 patients and to the occurence of an adverse effect for 9 patients. For 25 out of the 38 patients, the switch was a success according to the global physician's assessment 3 months after switching. This result was correlated to a significant decrease of DAS 28 measurements and CRP values (p < 0.05). The response after switching was recorded as a success for 18 out of the 24 patients who were treated with infliximab first, and for 12 out of the 14 patients who were treated with etanercept first. There was no statistical difference concerning the response after the switch between the two groups. Among the 29 patients who discontinued the first anti TNF-alpha treatment due to lack of efficiency, only 6 did not respond to the second anti TNF-alpha treatment. Only one out of the 9 patients who stopped a first anti TNF-alpha treatment after developing a side effect underwent an adverse event with the second anti TNF-alpha treatment. CONCLUSION: Our study suggests that switching between TNF-alpha antagonists seems to be relevant, regardless of which one was used first. It is legitimate to try to switch TNF-alpha blockers before contemplating other therapeutic strategies.

Adult↗
PubMedDate not supplied

Purification and some properties of collagenase proenzyme activator from rheumatoid synovial fluid.

1. An activator of leucocyte latent collagenase has been extracted from rheumatoid synovial fluid by a preparative method consisting of six steps including precipitation by ammonium sulphate and chromatography on Sephadex G-100, QAE-Sephadex and SP-Sephadex C-50. The purification factor was nearly 1000 and the activator isolated could be shown to have a high degree of homogeneity.--2. Gel chromatography indicated a molecular weight of ca. 60 000.--3. Kinetic studies of the activation and inactivation of the activator during incubation at higher temperatures demonstrated its enzymic nature.--4. Activation of latent collagenase was partially inhibited by iPr2P-F and KCN. Soybean trypsin inhibitor, iodoacetamide, TosLysCH2Cl and TosPheCH2Cl had no effect.--5. Leucocyte latent collagenase was also activated by an excess of trypsin and p-hydroxymercuribenzenesulphonic acid, but only to the extent of about 40% of its activation capacity. Purified neutral protease from human leucocyte granules had no effect on latent collagenase.--6. Several typical substrates for proteases, peptidases, esterases and glycosidases were not attacked by the activator. The possibility that the activator is a known enzyme, such as kallikrein, urokinase or cathepsin B1, could be excluded.

Arthritis, Rheumatoid↗
PubMedDate not supplied

[Multiple duodenal lipomas. A x-ray computed tomographic diagnosis].

In a 65-year-old man, upper endoscopy revealed several polypoid lesions into the duodenum, for which histologic examination of the biopsy specimens showed normal mucosa. CT studies demonstrated homogeneous fat density of these nodules, and thus were diagnostic of duodenal lipomas. The diagnosis was ultimately histologically confirmed by deeper peri-endoscopic biopsies. About this case and the some previously reported ones, the authors emphasize the interest of CT examination in this small bowel tumor.

Aged↗
PubMedDate not supplied

Syringomyelia associated with intradural extramedullary masses of the spinal canal.

Three cases of syringomyelia associated with intradural extramedullary tumors of the spinal canal are reported to demonstrate their radiographic feature, to postulate a mechanism for their formation, and to describe the clinical deterioration occurring in two patients immediately after metrizamide myelography. It is believed that the mechanism by which these syrinx cavities formed was similar to the mechanism of syrinx formation within chronically injured spinal cords. The cystic cavities may extend for considerable distances away from the extramedullary mass and may be present above and/or below the mass. The development of a syringomyelia in the face of an intradural extramedullary tumor may not be rare, and it is suspected that with the more frequent use of delayed metrizamide CT and now magnetic resonance imaging, syringomyelia will be found as an occasional consequence of this type of mass.

Adult↗
PubMedDate not supplied

Blood pressure and body mass index in Ethiopian immigrants: comparison of operations Solomon and Moses.

Blood pressure, height and weight of 122 male and 143 female Ethiopian Jews who immigrated to Israel in Operation Solomon (1991) were measured and compared with those of Ethiopian immigrants who arrived in Israel in 1984-85 (Operation Moses). Although the body mass indices of the Operation Solomon immigrants were much higher than those of Operation Moses, no significant differences were found in blood pressure measurements in any age-group or in either sex. Blood pressure in Operation Solomon immigrants increased with age and correlated with body mass index and triglyceride serum levels among males, but not females. No correlation was found between cholesterol levels and blood pressure measurements.

Adolescent↗