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Biomedical subjects

A Fried

Publications and source records attributed to A Fried.

At least 55 records · Page 3Linked to original sources
PubMed1985

Experimental feline hydrocephalus. The role of biomechanical changes in ventricular enlargement in cats.

In a craniectomy-durectomy model of kaolin-induced feline hydrocephalus, the pressure-volume index (PVI) technique of bolus manipulations of cerebrospinal fluid (CSF) was used to study the biomechanical changes associated with hydrocephalus. Steady-state intracranial pressure (ICP), PVI, and the resistance to the absorption of CSF were determined acutely and 3 to 5 weeks later in hydrocephalic cats and time-matched control cats. Steady-state ICP was 11.0 +/- 2.1 mm Hg (+/- standard deviation) in the hydrocephalic cats, compared to 10.8 +/- 2.2 mm Hg in the chronic control group (p greater than 0.1). The ICP in both the chronic hydrocephalic and chronic control groups was significantly higher (p less than 0.001) than after acute durectomy (mean ICP 8.5 +/- 1.2 mm Hg). Immediately after dural opening, the mean PVI was 3.6 +/- 0.2 ml (+/- standard error of the mean); over time, it decreased to 1.3 +/- 0.1 ml in the chronic control group (p less than 0.001), but remained elevated in the hydrocephalic group at 3.5 +/- 0.4 ml (p less than 0.001). Resistance to CSF absorption was 9.1 +/- 1.4 mm Hg/ml/min immediately after dural opening and increased to 28.8 +/- 4.5 mm Hg/ml/min (p less than 0.001) in the hydrocephalic cats; it increased even further in the chronic measurements in control cats, to 82.3 +/- 9.2 mm Hg/ml/min (p less than 0.001). Ventricular size was moderate to severely enlarged in all hydrocephalic cats, and normal in the control group. These results indicate that the biomechanical profile of the altered brain container model of kaolin-induced feline hydrocephalus resembles that described in hydrocephalic infants. As shown in the control subjects, an absorptive defect alone is not sufficient to cause progressive ventricular enlargement. Increased volume-buffering capacity coupled with a moderate increase of CSF absorption resistance facilitates volume storage in the ventricles.

Absorption↗
PubMed1984

Affinity labeling of the aldehyde site of bacterial luciferase.

2-Bromo[1-14C]1-decanal was synthesized as an affinity labeling probe for the aliphatic aldehyde site of Vibrio harveyi luciferase. In the presence of excess amounts of this probe, the inactivation of bacterial luciferase occurred following apparent first order kinetics. This inactivation was markedly retarded in the presence of decanal but neither butanal (a very poor aldehyde substrate) nor FMN (a reaction product derived from reduced FMN) showed any significant protective effect. Upon mixing luciferase with the affinity labeling probe, a noncovalent complex was formed prior to the covalent attachment. At pH 6 and 23 degrees C, the dissociation constant for the binding step and the rate constant for the covalent modification step were determined to be 23 microM and 1 min-1, respectively. The displacement of a bound aldehyde substrate by this probe added secondarily was also demonstrated. The inactivation of luciferase was correlated with both the incorporation of about 1.2 molecules of the probe and the loss of 0.8 to 1.1 cysteinyl residues/luciferase alpha beta dimer. The presence of an essential sulfhydryl group at the aldehyde site of luciferase has thus been demonstrated. This sulfhydryl group was a constituent residue of the alpha subunit and was near the alpha beta subunit interface. This residue appears to be the same essential cysteinyl group previously identified by chemical modification (Nicoli, M.Z., Meighen, E.A., and Hastings, J.W. (1974) J. Biol. Chem. 249, 2385-2392). The labeled luciferase did not exhibit any significant binding for the reduced FMN substrate.

Affinity Labels↗
PubMed1979

Ultrasonography in the diagnosis of tumors of the ovary.

Ultrasonography was performed prior to operation upon 60 patients with tumors of the ovary. This procedure was accurate in differentiating tumors of the ovary from other types of tumors of the pelvis in more than 90 per cent of the patients. Likewise, a determination between benign and malignant lesions of the ovary could be reliably made on the basis of ultrasonic patterns. These findings suggest that ultrasonography should be performed on all patients suspected of having a tumor of the ovary.

Adenocarcinoma↗
PubMed1977

Fractures of the femoral neck in childhood. Results of conservative treatment.

Experience with nine patients with fracture of the femoral neck in childhood, eight of whom were treated conservatively by closed reduction and fixation with a plaster cast, and one in whom Steinmann pins and open reposition had to be employed to accomplish fixation, is presented in brief. In six children the results were evaluated as good and in three (including the one case of open reduction) as fair. No serious complications were observed. The problem of nonsurgical versus surgical approach is discussed in the light of the relevant literature. It is suggested that while there can be no set rule as to which treatment should be used, conservative management yields results which are comparable with those attained with a more aggressive approach.

Adolescent↗
PubMed1977

Spontaneous tendon ruptures in patients treated by chronic hemodialysis.

Patients with renal failure treated by chronic hemodialysis tend to spontaneous tendon ruptures. In five out of 35 patients, 8 ruptured tendons have been found--four quadriceps and four finger tendon ruptures. Finger tendon ruptures are usually ignored by the patients because of the low disabling factor in the presence of more vital problems. Secondary hyperparathyroidism was found in all patients who had tendon ruptures and may possibly be the major disposing factor. The patients with tendon ruptures in our series were significantly younger than those without ruptures and had been treated for a longer period of time by hemodialysis, indicating that, whatever the reason for the ruptures, it seems to be a time-related phenomenon.

Adult↗
PubMed1976

Influence of dimercaprol on the early hepatic uptake of 111In-bleomycin in the BALB/c mouse.

Dimercaprol (BAL) administered 1 hr before 111In-bleomycin in the normal BALB/c mouse produced an early preferential hepatic loading of 111In-bleomycin without a loading of the spleen, skin, bone, or muscle. Liver-to-muscle ratios were increased about threefold under the influence of BAL. Liver (c BAL)/liver (s BAL) ratios also increased threefold at 3 hr whereas relative muscle uptake remained at about unity. Indium-111 chloride (colloid, pH 6.5) used as a control did not show a similar increase. The findings suggest that the kinetics and distribution of 111In-bleomycin in the normal BALB/c mouse can be influenced by pretreatment with BAL.

Animals↗