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Biomedical subjects

B Brenner

Publications and source records attributed to B Brenner.

At least 271 records · Page 15Linked to original sources
PubMed1986

Postsplenectomy pericardial effusion in two patients with myeloid metaplasia.

Self-limited sympathetic pleural effusion is a well-known nonspecific sequela following any upper abdominal surgery, including splenectomy. However, to our knowledge, there is no report in the literature on sympathetic pericardial effusion immediately following splenectomy. We describe two patients with agnogenic myeloid metaplasia and refractory hemolytic anemia in whom pericardial effusion appeared a few days after splenectomy. The possible pathophysiologic mechanism is discussed.

Female↗
PubMed1985

Equatorial x-ray diffraction from single skinned rabbit psoas fibers at various degrees of activation. Changes in intensities and lattice spacing.

Equatorial x-ray diffraction patterns were obtained from single skinned rabbit psoas fibers during various degrees of activation under isometric conditions at ionic strength 170 mM and 6-9 degrees C. By direct calcium activation, contraction was homogeneous throughout the preparation, and by using a cycling technique (Brenner, 1983) integrity of the fiber was maintained even during prolonged steady activation. The intensity ratio of the two innermost reflections I11/I10, and the normalized intensities I*10 and I*11 varied linearly with increasing force. Thus the result agreed qualitatively with an earlier finding, obtained from the whole sartorius muscle, that intensity changes in 10 and 11 are directly correlated with isometric force level (Yu et al., 1979). Spacing of the myofilament lattice (d10) was found to decrease with increasing isometric tension. With the filaments in full overlap, maximum shrinkage was 14%. The lattice spacing started to level off when the degree of calcium activation was greater than or equal to 50%, approaching a limit approximately at 380-360 A. This decrease of the lattice spacing indicates that there is a radial force produced by force generating cross-bridges, but the net radial force appears to become insignificant as lattice spacing approaches 380-360 A.

Animals↗
PubMed1985

Sarcomeric domain organization within single skinned rabbit psoas fibers and its effects on laser light diffraction patterns.

Total intensity and fine structure of first-order laser light diffraction maxima from single skinned rabbit psoas fibers were studied. Total intensity of the diffraction maxima was measured as a function of the incidence angle (omega-scan). In the most homogeneous fibers, most of the intensity in the diffraction maxima is confined to a rather narrow range of incidence angles. Fibers with less homogeneous striation patterns, apparently composed of several regions of distinct sarcomere length and tilt of striation (domains), give rise to several narrow intensity peaks in their omega-scans. Left and right first-order diffraction lines produce omega-scans of almost identical shape, composed of one or more intensity peaks, with each pair of corresponding peaks separated by about the same angle. The data indicated that in single skinned rabbit psoas fibers, light diffraction is dominated by Bragg diffraction and that the peaks within omega-scans can be directly correlated with domains within the illuminated fiber segment. In the most homogeneous fiber segments the diameter of domains, estimated from the width of the corresponding maxima in the omega-scans, could almost be as large as the fiber diameter. On average, from the number of peaks in the omega-scans two to three domains with an average length of approximately 250-350 microns can be identified in a fiber cross-section. Therefore, on average only a small number of domains (8 per mm) are found within skinned rabbit psoas fiber segments. In contrast, the number of substructural lines within the diffraction maxima is large even for microscopically homogeneous fibers. Substructural lines appear to be present only when several domains are illuminated simultaneously. Separation and width of these substructural lines are approximately inversely proportional to the length of the illuminated region of the fiber. These data suggest that the substructural lines are due to interference between domains, illuminated simultaneously by a light source with a high degree of spatial coherence (laser). The relevance of these findings for measurements of sarcomere length by laser light diffraction is discussed.

Animals↗
PubMed1985

A laser diffraction method for measuring muscle sarcomere length in vivo for application to tendon transfers.

A technique that uses laser light diffraction to measure muscle sarcomere length allows direct determination of optimal muscle length during tendon transfers. Forearm muscle sarcomere length with the hand in the position of function is 2.4, and muscle length corresponds directly to sarcomere length. We have used these observations to restore optimal muscle length during tendon transfers. Standard high radial nerve tendon transfers in six fresh cadaver forearms demonstrated the efficacy of the laser diffraction method in accurately measuring sarcomere length. In two clinical trials with the laser, standard high radial nerve palsy tendon transfers were performed. In each case the clinical tendency was to overpull the muscle during the transfer. With the laser it was possible to identify excessive muscle stretch and restore optimal muscle length.

Forearm↗
PubMed1985

Severe pancytopenia due to marked marrow fibrosis associated with angioimmunoblastic lymphadenopathy.

A patient with angioimmunoblastic lymphadenopathy (AILD) is presented. Manifestations of the disease appeared after short-term treatment with oxprenolol hydrochloride. Following treatment with prednisone, the patient remained in remission for 25 months. The disease relapsed following reuse of oxprenolol hydrochloride. Severe pancytopenia due to bone marrow involvement by AILD and myelofibrosis led to a fatal outcome. The association of AILD and myelofibrosis has been rarely encountered and is hereby discussed. In addition, the possible relationship between AILD and oxprenolol hydrochloride is considered.

Angina Pectoris↗
PubMed1985

Hydatid cyst of the liver rupturing into the biliary tract--mimicking acute cholecystitis on hepatobiliary scanning.

Two patients presenting with right upper abdominal colicky pain, jaundice, and fever had a hepatobiliary scan using Tc 99m HIDA. The scan was suggestive of acute cholecystitis and a space occupying lesion in the liver. On operation, liver echinococcosis, located in the right lobe rupturing into the biliary ductal system, was found. Intraoperative cholangiography revealed filling defects in the main biliary ducts. Exploration of the common bile duct disclosed daughter cysts and cystic debris. Acute cholecystitis or stones were not found. We conclude that in patients with a clinical picture and HIDA scanning compatible with acute cholecystitis and a space occupying lesion in the liver, the diagnosis of hydatid cyst of the liver which has ruptured into the biliary tract should be considered.

Acute Disease↗
PubMed1984

Cross-bridge attachment in relaxed muscle.

We have measured the stiffness of relaxed, skinned rabbit psoas fibers at 5 degrees C in low ionic strength relaxing solution (mu = 0.02 M) by stretching the fibers and measuring the resulting force and sarcomere length changes. This stiffness is very dependent upon the velocity of stretch. With very slow stretches (0.5% of fiber length in greater than 30 ms), it is almost negligible but with stretches as fast as 0.5% of fiber length in 150 microseconds, the stiffness approaches 1/3 that of the rigor fiber. This stiffness is also very sensitive to ionic strength, being reduced more than 20-fold at an ionic strength of 0.17 M. This ionic strength sensitive stiffness scales with the amount of overlap between the actin and myosin filaments which strongly suggests that it is due to attached cross-bridges. The speed dependence suggests that the attached cross-bridges are not statically attached but in rapid equilibrium between attached and detached states. Experiments with adenylyl-imido-diphosphate suggest that the rates of attachment and detachment depend upon nucleotide.

Adenosine Triphosphate↗
PubMed1984

X-ray diffraction evidence for cross-bridge formation in relaxed muscle fibers at various ionic strengths.

Equatorial x-ray diffraction patterns from single skinned rabbit psoas fibers were studied at various ionic strengths to obtain structural information regarding cross-bridge formation in relaxed muscle fibers. At ionic strengths between 20 and 50 mM, the intensity of the 11 reflection, I11, of the relaxed state was close to that of the rigor state, whereas the intensity of the 10 reflection, I10, was approximately twice that of rigor reflection. Calculations by two-dimensional Fourier synthesis indicated that substantial extra mass was associated with the thin filaments under these conditions. With increasing ionic strength between 20 and 100 mM, I10 increased and I11 decreased in an approximately linear way, indicating net transfer of mass away from the thin filaments towards the thick filaments. These results provided evidence that cross-bridges were formed in a relaxed fiber at low ionic strengths, and that the number of cross-bridges decreased as ionic strength was raised. Above mu = 100 mM, I10 and I11 both decreased, indicating the onset of increasing disorder within the filament lattice.

Actins↗
PubMed1984

Pancoast's syndrome in multiple myeloma.

A 74-year-old patient developed IgG multiple myeloma. 7 months later a right Pancoast's syndrome was observed. Computerized tomography established the extrapleural origin of the tumor. Fine needle aspiration revealed pathological plasma cells. Partial reduction of plasmacytoma was noted following radiotherapy, but the patient succumbed to pneumonia. Autopsy confirmed that a plasmacytoma caused the Pancoast's syndrome. The importance of early diagnosis and accurate therapy of this rare manifestation of multiple myeloma is discussed.

Aged↗
PubMed1984

Acute leukemia following chemotherapy and radiation therapy--a report of 15 cases.

14 patients developed acute nonlymphocytic leukemia and 1 patient developed Burkitt's leukemia following longterm chemotherapy and/or radiotherapy for other disorders. The main primary disorders included multiple myeloma, Hodgkin's disease, non-Hodgkin's lymphoma and breast carcinoma. Acute leukemia developed earlier in patients treated by chemotherapy with or without radiotherapy than in patients treated by radiotherapy alone (63 months, range 24-132 months; 201 months, range 48 months to 30 years, respectively). 13 patients presented without organomegaly and 8 were pancytopenic. Abnormalities of myeloid and erythroid cell lines were observed in the majority of the patients. A high rate of acute erythroleukemia (5 out of 14) was found. Increased reticulin fibers were found in 3 patients. The leukemia was invariably refractory to treatment with a median survival of 4 months. The possible role of preexisting abnormal marrow structure in the development of therapy-related leukemia is discussed.

Acute Disease↗