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Biomedical subjects

P Bloch

Publications and source records attributed to P Bloch.

At least 91 records · Page 5Linked to original sources
PubMed1978

Tolerance of the human liver to prolonged normothermic ischemia. A biological study of 20 patients submitted to extensive hepatectomy.

To evaluate the biological tolerance of the human liver to prolonged warm ischemia, two groups of extensive hepatic resection for tumor were compared. Group 1 (11 patients) performed with short hepatic inflow occlusion (7 [mean] +/- 2 [SEM] minutes), and group 2 (nine patients) operated with use of complete hepatic vascular exclusion and prolonged warm liver ischemia (38 [mean] +/- 5 [SEM] minutes). Comparison of biological values, such as transaminase, bilirubin, total protein, albumin, and fibrinogen levels, the platelet count, prothrombin complex, and proaccelerin level, did not show statistically significant differences between the two groups. Therefore, the hepatic warm ischemia period may be, if needed, safely extended beyond the classical 15 minutes. It lasted 65 minutes in one case without adverse effect. These clinical observations parallel recent experimental work and should destroy the myth of the high sensitivity of the liver to warm ischemia.

Adolescent↗
PubMed1978

X-ray fluorescence analysis of lead in teeth of urban children in situ: correlation between the tooth lead level and the concentration of blood lead and free erythroporphyrins.

The tooth lead level of 30 lead-exposed children was measured in situ using an X-ray fluorescence technique. The tooth lead concentration divided by the child's age correlated with the free erythroporphyrin (FEP) (r = 0.51) and the blood lead levels (r = 0.31). The mean tooth lead concentrations of 10 Class IV children (FEP greater than or equal to 190 micrograms/100 ml; blood lead 30-80 micrograms/ml) was 14.5 +/- 5.5 ppm/year. Reexamination of the histories of children who had been classified as Class II or III, but who had tooth lead concentrations within 1 SD of the Class IV level, indicated that many of these children could also be considered to be Class IV children. When the x-ray fluorescence technique was used to screen an urban population of 300 children, the tooth lead values indicated that 72% of the children had been exposed to low levels of environmental lead. Six percent of the children were found to have tooth lead concentrations in excess of 9 ppm/year and within 1 SD of the mean value exhibited by Class IV children. These children were considered to have a high body lead burden. The percentage of children having an elevated tooth lead level is similar to the number previously reported using exfoliated deciduous teeth.

Child↗
PubMed1978

Step-wedge sensitometry.

An aluminum step-wedge filter placed far from the film cassette provides the constant variation of subject contrast required for quantitative sensitometry while virtually eliminating scatter radiations. Attenuation curves made with this configuration are almost exponentially linear.

Radiography↗
PubMed1978

[Oesophageal perforations from instrumentation during high fibroscopy. Radiological signs (author's transl)].

The authors report on a survey of perforation following fibroscopy in the Hôpital Saint-Antoine. A total of 10,600 diagnostic examinations were reviewed and 5 perforations were recorded, to which must be added 2 perforations following oesophageal dilatation. A chesy X-ray, taken within 24 hours of the incident, showed, in most cases, the presence of air in the mediastinum with early signs of subcutaneous emphysema in the cervical or cervicothoracic regions. A hydro-pneumothorax in the right side of the chest was also observed in the cases studied, without air in the mediastinum. Oesophageal transit was studied by means of a water-soluble compound, and showed oesophageal effraction in only 4 cases, and in 3 of these cases it was possible to see the location of the orifice with precision.

Adult↗
PubMed1978

Hemodynamic monitoring during complete vascular exclusion for extensive hepatectomy.

Hemodynamic monitoring during normothermic vascular exclusion of the liver, with or without clamping of the upper part of the abdominal aorta appears mandatory, based upon an experience with ten patients. Nine patients underwent extensive liver resection for major tumors unsuitable for conventional surgical procedures. No operative accidents were observed. Permanent monitoring during the procedure included pulmonary artery pressures, radial artery pressures, heart rate and cardiac output, measured by the thermodilution method. Hemodynamic changes after short isolated venous or aortic and combined clampings were also studied. With this procedure, the most critical period occurred immediately after the release of the clamps, with a major rise in the pulmonary artery pressures, which led to hemodynamic pulmonary edema level. The acute modifications of circulating blood volume actually carried a high risk of vascular overloading, and the most reliable method to avoid this was the permanent control of the pulmonary artery pressures. Blood volume replacement was, at its best, adjusted with the use of such a parameter, especially when hemorrhage was important. Combined aortic clamping reduced blood losses and minimized pooling in the splanchnic area and the lower extremities.

Adult↗
PubMed1978

Normothermic hepatic vascular exclusion for extensive hepatectomy.

In humans, there is still considerable controversy concerning the tolerance of the liver to warm ischemia. To avoid anoxic hepatocellular damage, chilled intraportal and intra-arterial infusion has been advised as an adjunct to hepatic vascular isolation. Fourteen patients with hepatic tumors underwent extensive hepatic resection, complete hepatic vascular exclusion being used but without the use of refrigeration. This procedure may considerably reduce blood loss during resection of large and hypervascular hepatic tumors and increase the safety of hazardous lobectomies. Careful hemodynamic monitoring including pulmonary artery pressure is necessary. Hepatic tolerance to prolonged warm ischemia up to 65 minutes is surprisingly good, in the absence of preoperative, extensive hepatic dysfunction. The use of this procedure is advised for resection of large hepatic tumors when the technical risks appear to be high. It is suggested that the classical delay of 15 to 20 minutes of normothermic hepatic ischemia may be safely extended to about one hour when necessary.

Adult↗
PubMed1977

An electron microscopic and enzymic study of rat liver peroxisomal nucleoid core and its association with urate oxidase.

The appearance of the characteristic crystalloid core of rat liver peroxisomes is emulated by the electron microscopic (EM) appearance of highly purified urate oxidase prepared from the same tissue. The purity of the enzyme preparation was established by gel electrophoresis under various conditions and the specific enzyme activity was at least as high as any previously reported. The amino acid composition of urate oxidase was determined. As additional evidence for close association of the peroxisomal core with urate oxidase, it was demonstrated that the biphasic changes in rat liver urate oxidase activity in response to prolonged starvation were paralleled by changes in the EM appearance of peroxisomes. Under comparable conditions catalase, another peroxisomal enzyme, did not show the same changes in activity as did urate oxidase. Evidence for the possible identity of urate oxidase with the peroxisomal crystalloid of rat liver has been presented, all materials having been obtained from, and experiments performed with, the rat.

Amino Acids↗
PubMed1977

Measurement of lead content of children's teeth in situ by x-ray fluorescence.

The central nervous system of young children is particularly sensitive to neurological damage due to excessive lead exposure. The lead stored in a tooth is permanent and related to the quantity of ingested lead. The lead is assayed by measuring the characterisitc radiation from lead in a tooth in situ irradiated with gamma rays from a cobalt-57 source. The sensitivity of the method is adequate to measure lead levels commonly associated with environmental background. The X-ray exposure to the tooth necessary for this determination is approximately one tenth of that required for a routine dental examination.

Child↗