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Biomedical subjects

G Strauss

Publications and source records attributed to G Strauss.

At least 91 records · Page 5Linked to original sources

Preirradiation chemotherapy of supratentorial malignant primary brain tumors with intracarotid cis-platinum (CDDP) and i.v. BCNU. A phase II trial.

Thirty patients with histologically verified malignant supratentorial gliomas were treated with a preirradiation chemotherapy protocol consisting of two courses of intracarotid (i.c.) CDDP, 90 mg/m2, followed by i.v. BCNU, 200 mg/m2. Side effects from therapy were mild and self-limiting; no irreversible retinal or neurologic toxicity could be attributed to i.c. chemotherapy. Of the 27 patients who completed the chemotherapy portion of the protocol, tumor size on postchemotherapy computed tomography (CT) was decreased by greater than 50% in 13% as compared to the postoperative CT scan; in only 4% was the CT scan unequivocally increased in size. Twenty-five (83%) patients completed the entire protocol. Median time to tumor progression and survival in patients who completed the protocol was 53 (range of 13-130+) and 61 (range of 29-130+) weeks, respectively. Twenty-four percent of patients still have not demonstrated tumor progression at intervals greater than 1 year after diagnosis as judged by clinical and radiographic criteria. Tumor recurrences were always contiguous to the original tumor bed. We conclude that preirradiation chemotherapy may be administered safely and with low morbidity. Further study to determine an optimal timing between chemotherapy and radiation therapy is warranted.

Adult↗

Considerable deficits in the detection performance of the cat after lesion of the suprasylvian visual cortex.

The ability of two cats to discriminate between two geometrical outline patterns in the presence of superimposed structured background was tested before and after bilateral removal of the lateral suprasylvian visual areas (PMLS, PLLS, AMLS, ALLS, part of area 7). There were mild deficits when patterns and background were kept stationary; these deficits may be due to a partial undercutting of areas 17, 18 and 19. However, there was a severe impairment in performance when the patterns were moving on a stationary background which may be due to loss of the suprasylvian visual areas. Movement of the background relative to the figure resulted in an intermediate detection deficit.

Animals↗

Should prophylactic anticonvulsants be administered to patients with newly-diagnosed cerebral metastases? A retrospective analysis.

We analyzed a retrospective series of 195 patients with documented intracerebral metastases (ICM) to assess the frequency of late seizure development and the impact of prophylactic anticonvulsants. Eighteen percent of the patients presented with seizures. Of the remaining patients, 40% received prophylactic anticonvulsants (diphenylhydantoin [DPH] in greater than 90%). Ten percent developed late seizures at an interval from the diagnosis of ICM ranging from 1 to 59 weeks. No patient with a posterior fossa lesion developed seizure; conversely, patients with evidence on initial examination of cerebral hemispheric dysfunction had a higher incidence of late seizure development. The incidence of seizure was virtually identical in patients who received DPH compared with those in whom it was withheld, although two thirds of patients who developed seizure while on DPH had a serum anticonvulsant level that was subtherapeutic. Based on the above findings and until prospective data become available, we recommend that anticonvulsants be withheld in newly-diagnosed patients with ICM until the first seizure.

Adult↗

Reactions to vesical foreign bodies in two strains of rats.

Foreign bodies in the urinary tract induce uroliths. This study examined reactions to vesical foreign bodies in Brattleboro rats manifesting diabetes insipidus and Sprague-Dawley rats. A silk suture was placed in the bladder of these rats and the occurrence of vesical uroliths, stone composition, and mucosal morphology were examined. Sprague-Dawley rats readily formed bladder stones in addition to a urolith formed over the suture, but there was little evidence that Brattleboro rats developed similar stones. Stone composition was primarily ammonium magnesium phosphate. The mucosal reactive hyperplasia was pronounced in the Sprague-Dawley, but was negligible in the Brattleboro rats. In conclusion, vesical foreign bodies readily induced uroliths in Sprague-Dawley rats, but there was no similar evidence in Brattleboro rats. It is suggested that the excessive diuresis of the latter may play a major role for this resistance to form stones, but the precise mechanisms of it are complex and remain to be explored.

Animals↗

The interaction of saccharides with lipid bilayer vesicles: stabilization during freeze-thawing and freeze-drying.

The fusion of small unilamellar vesicles of phosphatidylcholines during freeze-thawing and freeze-drying/rehydration, and the suppression of fusion under these conditions by various saccharides, was investigated by gel filtration on Sepharose 4B, quasielastic light scattering, high-resolution 1H-NMR, ESR spin labeling, and differential scanning calorimetry. Freeze-thawing and freeze-drying of aqueous small unilamellar vesicle suspensions in the presence of sufficient sucrose had no significant effect on the average size and size distribution of small unilamellar vesicles. In the presence of sucrose the structural integrity and the permeability properties of the phosphatidylcholine bilayers were retained during freeze-thawing and freeze-drying. A comparison of the stabilizing effect of sucrose with that of trehalose and glucose showed that the stabilization is not sugar-specific but is a general property of saccharides. The fraction of small unilamellar vesicles recovered after freeze-thawing depended on the saccharide/phosphatidylcholine molar ratio. The mechanism of the cryoprotective effect involves binding of the sugar to the phospholipid polar group, probably through hydrogen bonding.

Calorimetry, Differential Scanning↗

Stabilization of lipid bilayer vesicles by sucrose during freezing.

The freeze-induced fusion and leakage of small unilamellar vesicles (SUV) of natural and synthetic phosphatidylcholines and the suppression of these processes by sucrose was studied by electron microscopy, by high-resolution NMR, and by ESR techniques. During slow freezing of SUV suspensions in water, the lipid was compressed into a small interstitial volume and transformed into a multilamellar aggregate without vesicular structure. When frozen in sucrose solution, the lipid also was compressed between the ice crystals but remained in the form of vesicles. The fractional amount of lipid remaining as SUV after freezing was found to increase significantly only at sucrose/lipid molar ratios above 0.4. Eu(3+) displaced sucrose from the lipid by competitive binding. During freezing in the absence of sucrose, the vesicles became transiently permeable to ions. ESR studies showed that fusion of vesicles in the absence of sucrose is far more extensive when they are frozen while above their phase-transition temperature (t(c)) than when frozen while below their t(c). It is concluded that the extent of membrane disruption depends on the membrane mobility at the moment of freezing and that sucrose exerts its protective effect by binding to the membrane interface and/or by affecting the water structure.

Journal Article↗

Herpes simplex virus defective genomes: structure of HSV-1 ANG defective DNA of class II and encoded polypeptides.

Sequence organization and origin of HSV-1 strain Angelotti (ANG) class II defective DNA (HSV-1 ANG dDNA1) were examined in detail by establishing physical maps and by molecular cloning. dDNA1 consists of concatemers of tandem repeat units in which sequences from the UL region spanning map coordinates 0.37 to 0.415 of standard HSV ANG DNA are covalently linked to TRS/IRS sequences. The size of the repeat unit was determined to be about 8.9 kilobase pairs (kb), comprising sequences of 7.3 kb from UL and 1.6 kb from TRS/IRS regions. UL sequences were delineated by restriction enzyme sites KpnI N-P and EcoRI F-M, and were colinear with the corresponding sequences of the standard (wild-type) virus genome. Expression of dDNA1 was studied in African green monkey kidney cells and in Xenopus laevis oocytes. A major polypeptide of approx. mol. wt. 135 000 (135K) was overproduced, suggesting that this protein was encoded by dDNA1. By several parameters, e.g. size, immune cross-reactivity, and affinity for native and denatured DNA, the 135K polypeptide was identified as the major HSV DNA-binding protein. It was further shown that the repeat unit contains part of the DNA polymerase gene as demonstrated by its ability to rescue some mutations in this gene.

Base Sequence↗

[Immunosuppressive treatment of multiple sclerosis. 4. Results of treatment with azathioprine and antilymphocyte globulin (author's transl)].

During the long-term treatment with azathioprine of 79 patients suffering from MS there was a significant reduction in the relapse rate; the course of the disease was also favorabley influenced. In about one third of the patiens afflicted with the chronic progressive form of MS, there was no further progression. After conclusion of the treatment its favorable effect lasted for 1 to 2 years; then the disease worsened, and the relapse rate increased again. Treatment with antilymphocyte globulin and/or thoracic duct drainage in 18 patients led to impressive improvement or a stabilization of the neurological signs in those with a relapsing course. The chronic progressive course of MS was arrested in about two thirds of the patients. The effect of the treatment lasted from one to several years.

Antilymphocyte Serum↗

[Compensative dilatation of the vena azygos by abnormalities of the vena cava inferior - a contribution to the differential diagnosis of the tumorsuspected right tracheobronchial angle (author's transl)].

Report on 2 patients, with a mediastinal enlargement at the right tracheobronchial angle revealing an ectasis of the orifice of vena-azygos. It could be shown that the enlargement of the vena azygos ist due to an increase of the flow-volume, caused by an abnormal embryonic drainage of the vena cava inferior into the vena azygos. The diagnostic possibilities for differentiation from vascular and nonvascular space-occupying processes in that region are discussed. An exact diagnosis is possible by angiography.

Adolescent↗

[Rationalization and standardization in the diagnostic of pleural effusions (author's transl)].

238 pleural effusions found within five years among our patients were investigated according to a prospective fixed scheme, and analysed according to diagnostic groups. In accordance with other authors a predominance of the malignant pleural effusions was evident. Besides the cytohistologic diagnosis proving 84,6% of the pleural effusions of malignant origin, some of the biochemical parameters are of decisive value. In our opinion laboratory examinations should be abandoned which do not contribute effectively to establish the diagnosis. For rationalization a routine programme with five examinations is being proposed: total protein and specific gravity, pH, bacterial examination and cytology.

Adolescent↗