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Biomedical subjects

G Fisher

Publications and source records attributed to G Fisher.

At least 91 records · Page 5Linked to original sources
PubMed1984

Recurrent focal glomerulosclerosis in renal transplants.

Among 431 renal transplants in 380 patients, 4 patients were identified with focal glomerulosclerosis characterized by presentation with corticosteroid-resistant nephrotic syndrome, early development of histological lesions, mesangial proliferation and rapid progression into chronic renal failure. After transplantation, all patients had early proteinuria and the 4 grafts surviving beyond 3 months developed recurrent glomerular lesions with severe nephrotic syndrome and progression to graft failure. In one patient, recurrent disease developed in two successive grafts. Focal glomerulosclerosis is a nonspecific glomerular lesion, but identification of specific clinical and pathological features may provide guidelines that will predict the risk of its recurrence in transplanted kidneys.

Adult↗
PubMed1982

Compression-sclerotherapy for varicose veins: a Canadian study.

In recent years modifications and refinements in treating varicose veins by injecting a sclerosant have given this method an important place in the practitioner's armamentarium. Specific indications and precise technique are essential. Compression-sclerotherapy has been used since 1975 in the vein clinic of Belleville General Hospital, Belleville, Ont. Some patients have also required limited ligation of veins that were deeper or more proximal, or both. A follow-up study of patients 2 or more years after treatment revealed no major complications and a high rate of patient acceptance and satisfaction. The costs of treatment were about one tenth those of conventional inpatient surgery.

Adult↗
PubMed1982

Use of an inversion to test for induced X-linked lethals in mice.

A long X-chromosomal inversion in the mouse was used to suppress crossing-over and thereby to scan 85% of the X-chromosome, or 5% of the genome, for recessive lethal mutations induced by radiation. After a fractionated absorbed dose of 500 + 500 rad X-rays 24 h apart to spermatogonia, 2/536 irradiated and 0/529 control X-chromosomes carried a confirmed lethal. This corresponds to a rate for recessive lethals of 1.9 x 10(-6)/rad/X-chromosome for single exposures (allowing for the enhancing effect of fractionation). This is believed to be the first demonstration of the induction of transmissible X-linked lethals in mammals. The results are consistent with previous findings by other methods and indicate the relatively low rate of induction of lethals and the value of inversions in detecting them.

Animals↗
PubMed1981

[An automatic method for analysis of the electroencephalogram of epileptics (author's transl)].

A new method for spike-detection in the EEG was developed. For the learning, and test-phase of the program the judgement of 7 experienced electroencephalographers was used. The EEGs of 10 epileptic patients and 9 clinically normal subjects were analyzed. 250 out of 341 "true" spikes were recognized and only 3 doubtless nonspikes were classified as spikes. A direct comparison between computer program and single EEG experts shows an equivalent in 3 of 7 cases. The average detected spike rate of non=epileptic subjects is a quarter of the average spike rate of the epileptic patient with the lowest epileptic activity. The program is now being tested in realtime in a centre for epilepsy in the Netherlands.

Computers↗
PubMed1981

Radioprotection of normal and malignant tissue in the mouse by diethylaminoreserpine.

The protective effect of pre-irradiation injections of diethylaminoreserpine (DL-152) for normal and malignant tissues in the mouse has been investigated. Dose modifying factors (DMFs) obtained for normal tissue ranged from 1.0 for bone marrow CFUs to more than 1.8 for skin. The DMFs for two transplantable tumours investigated were 1.0 for the EMT6 adenocarcinoma and 1.70 for the KHT fibrosarcoma (at a surviving fraction of 0.1. Acutely hypoxic KHT tumours were protected to a slightly lesser extent than were aerated tumours. For the KHT tumour, the number of clonogenic cells recovered from non-irradiated tumours one hour after DL-152 injection was reduced to 60 per cent of the number covered fro saline-injected controls, while, if DL-152 injected mice were acutely hypoxic at the time of sacrifice, the number of clonogenic cells was further reduced. The survival of non-irradiated EMT6 tumour cells was unaffected by DL-152 injection prior to sacrifice.

Adenocarcinoma↗
PubMed1979

Dose-response curves for radiation-induced gene mutations in mouse oocytes and their interpretation.

Previous work, in which female mice had been given fractionated doses of 20 X 10 rad X-rays, had confirmed and extended Russell's observations that the dose-response relationship for specific-locus mutations in mature-mouse oocytes is curved at low doses. The present work was intended to study the relationship at relatively high doses. Adult female mice were given doses of 200, 400 or 600 rad x-rays at 52 or 72 rad/min, and mated immediately. Offspring conceived in the first 7 days (i.e. using oocytes which were mature at time of treatment) were scored for specific-locus mutations. The data indicate that the departure from linearity of the dose-response curve is marginally significant at the 5% level. A quadratic dose-response curve (y = c + aD + bD2) and a square-law relationship (y = c + bD2) both give a good fit to the data. Both curves fit data of other authors obtained at low doses or dose-rates. These results could be interpreted either in terms of dose-dependent repair phenomena, or by considering specific-locus mutations as two-track events. In view of knowledge of other phenomena concerning mutation and cell killing in mouse oocytes, such as the variation in sensitivity of different cell stages, the interpretation in terms of repair phenomena is preferred.

Animals↗
PubMed1977

The measurement of blood flow in mouse femur and its correlation with 239Pu deposition.

The concentration of 18F was measured in three parts of the femur and in the blood of 36 mice killed at intervals of from 1 min to 2 h after intravenous injection. Blood supply to the bone sections, calculated by dividing the increase in 18F concentration in bone by the integral of 18F concentration in blood between selected time intervals, was shown to be unaffected by the return of 18F from bone to blood at times earlier than 90 min following injection. The supply of blood per unit mass of bone was greatest in distal end of the femur, less in proximal end and least in shaft. In whole femur average blood flow was 230 mm3 per gram fresh bone per min. The deposition of 239Pu in three parts of the mouse femur was shown to be linearly related to blood flow and the nature of the relationship is discussed.

Animals↗
PubMed1977

GLC determination of opium alkaloids in papaveretum.

A GLC method for the determination of the opium alkaloids in papaveretum, based on the formation of the acetyl derivatives of morphine and codeine, is described. The analytical results are compared with those obtained by the official method. The proposed method is fast and accurate and is particularly suited to the analysis of the raw material.

Chromatography, Gas↗
PubMed1976

Inhibitors of the luteinizing hormone-releasing hormone based upon modifications in the 2, 3, and 6 positions.

[Leu2,Leu3,D-Ala6]-LH-RH (less than Glu-Leu-Leu-Ser-Tyr-D-Ala-Leu-Arg-Pro-Gly-[NH2) and [Val2,Leu3,D-Ala6]-LH-RH completely inhibited the release of LH and FSH induced by 0.3 ng/ml of medium of LH-RH on isolated rat pituitaries, at a dosage of 10 mug. [Leu2,Val3,D-Ala6]-LH-RH and [Val2,Val3,D-Ala6]-LH-RH also completely inhibited this response but were one-tenth as active as [Leu2,Leu3,D-Ala6]-LH-RH. All of the analogs were devoid of agonist activities. The incorporation of the D-Ala residue in position 6 into the [Leu2,Leu3]-LH-RH sequence, therefore, increased the inhibition potency as much as tenfold.

Animals↗
PubMed1976

Divalent cation affinity sites in Paramecium aurelia.

Sites with high calcium affinity in Paramecium aurelia were identified by high calcium (5 mM) fixation and electron microscope methods. Electron-opaque deposits were observed on the cytoplasmic side of surface membranes, particularly at the basal regions of cilia and trichocyst-pellicle fusion sites. Deposits were also observed on some smooth cytomembranes, within the axoneme of cilia, and on basal bodies. The divalent cations, Mg2+, Mn2+, Sr2+, Ni2+, Ba2+, and Zn2+, could be substituted for Ca2+ in the procedure. Deposits were larger with 5 mM Sr2+. Ba2+, and Mn2+ at ciliary transverse plates and the terminal plate of basal bodies. Microprobe analysis showed that Ca and C1 were concentrated within deposits. In some analyses, S and P were detected in deposits. Also, microprobe analysis of 5 mM Mn2+-fixed P. aurelia showed that those deposits were enriched in Mn and C1 and sometimes enriched in P. Deposits were seen only when the ciliates were actively swimming at the time of fixation. Locomotory mutants having defective membrane Ca-gating mechanisms and ciliates fixed while exhibiting ciliary reversal showed no obvious differences in deposition pattern and intensity. Possible correlations between electron-opaque deposits and the locations of intramembranous particles seen by freeze-fracture studied, as well as sites where fibrillar material associate with membranes are considered. The possibility that the action sites of calcium and other divalent cations were identified is discussed.

Animals↗