Hepatic resection in the fetal rabbit. Histologic comparison of tissue regeneration in the fetus versus the adult

Fetal tissues present peculiar features of repair after injury. Although the development of fetal hepatocytes have already been studied in vitro and in transplant models, an in vivo study of fetal liver regeneration is still missed in the literature, to the best of our knowledge. Eight time-dated pregnant California rabbits (23, 24, 25, 30 days of gestational age) and 2 adult male California rabbits were anesthetized following a standardized i.v. protocol (ketamine 50 mg/kg; xilazine 5 mg/kg; propiopromazine 0.75 mg/kg; spontaneous breathing; no anesthetic gas). All the pregnant does underwent a midline laparotomy and a minimal hysterotomy to approach a fetus per each animal. In 2 cases, 1 fetus was delivered and prior to sacrifice the fetal liver was sampled in toto (30 days of gestational age). These pregnancies were allowed to continue to term and were uneventful with a full-term spontaneous delivery of the remaining fetuses. In the other 6 pregnancies, after the hysterotomy, the fetal abdomen was entered through a right-sided longitudinal incision and the liver was partially resected by thermocauterization. Fetal abdomen was closed in 1 layer (non absorbable suture 7-0). The fetus was then returned in the uterus and, after amniotic fluid restoration with warmed saline, the hysterotomy was sutured in double layer (polyglycolic 5-0). Maternal abdomen was closed in 1 layer (polyglycolic 4-0) and the skin in a continuous overlying fashion (silk 3-0). The abdominal cavity of the 2 adult male rabbits was entered through a right subcostal incision. Partial liver resection was performed, and abdominal and skin closure followed the same techniques used for the pregnant does. The treated livers were then sampled in toto at 24, 48, 72 hrs and 4 days after surgery from the fetuses, and at 7 days from the adult rabbits. Histological stains were: H & E; Van Gieson; Masson; Alcian Bleu; PAS. Fetal histology showed a low inflammatory reaction poor in PMN cells with minimal deposition of collagen and a high amount of glycogen in the hepatocytes. The inflammatory response to resection was much more evident in the adult samples as much as the abundant intra and extra-cellular deposition of collagen associated to a minor amount of intracellular glycogen. The peculiar features of liver regeneration in the fetus, deserve further experimental studies.     

Transient increase in circulating donor leukocytes after allogeneic transfusions in immunocompetent recipients compatible with donor cell proliferation

Donor leukocytes in therapeutic blood components are implicated in transfusion-related complications ranging from alloimmunization to graft-versus-host disease (GVHD) to viral transmission and reactivation. To further characterize the kinetics of donor leukocyte clearance after allogeneic transfusion, we developed allele-specific polymerase chain reaction (PCR) assays directed at a single-copy Y chromosome gene and HLA class II alleles. These assays enable sensitive detection and quantitation of donor leukocytes at concentrations ranging from one cell to greater than 1,000 cells per 125 microL of recipient blood. When applied to serial samples from five consecutive orthopedic surgery patients who met study criteria, we observed 99.9% clearance of donor leukocytes over the initial 2 days posttransfusion, followed by a transient, 1-log increase in circulating donor leukocytes on days 3 to 5. This phenomenon was reproduced in a canine transfusion model, where the transient donor leukocyte expansion phase was prevented by gamma irradiation of donor blood, and was not observed after transfusions into alloimmunized dogs. We hypothesize that this transient increase in circulating allogeneic donor cells represents one arm of an in vivo mixed lymphocyte reaction, with activated donor T lymphocytes proliferating in an abortive GVHD reaction to HLA-incompatible recipient cells. Further investigation of this phenomenon should provide insight into the mechanisms involved in donor-recipient leukocyte interactions posttransfusion and the relationship of these interactions to leukocyte-induced complications.     

A randomized trial to assess the efficacy of surgery in addition to radiotherapy in patients with a single cerebral metastasis

1. A comparison of the effects of dietary and genetically-induced hypercholesterolaemia on the vasodilator and antiaggregatory capacity of the endothelium was made in rabbit isolated subclavian artery rings. 2. Dietary-induced hypercholesterolaemia in NZW rabbits decreased the maximum relaxation to carbachol (0.01-10 microM) and calcimycin (0.01-0.1 microM) in vessel rings precontracted with 5-hydroxytryptamine (5-HT), 0.1 microM), when compared to responses observed in rings obtained from control normocholesterolaemic NZW rabbits. The relaxant responses to SIN-1 (3-(4-morpholinyl)-sydnonimine hydrochloride) were attenuated but were not significantly different from controls. In Froxfield genetically hypercholesterolaemic (FHH) rabbits, the maximum relaxations to carbachol, calcimycin and SIN-1 were all reduced significantly. 3. Neither genetic nor dietary-induced hypercholesterolaemia modified the contractile responses of vessel rings to either KCl (10-100 mM) or 5-HT (0.01-10 microM). 4. Endothelium-dependent inhibition of collagen-induced platelet aggregation in whole blood was demonstrated by stimulation of a vessel ring, incorporated into the blood sample, with carbachol (10 microM, final blood concentration). This effect was inhibited by NG-nitro-L-arginine (L-NOARG, 100 microM). SIN-1 (10 microM, final blood concentration) also decreased whole blood platelet aggregation, but only in the presence of an unstimulated vessel ring, and this was unaffected by L-NOARG. Superoxide dismutase (150 u ml-1) did not influence the inhibition of aggregation by either a carbachol-stimulated vessel ring or by SIN-1. 5. Carbachol-stimulated artery rings from FHH rabbits inhibited platelet aggregation to a similar extent to that seen with rings from control normocholesterolaemic rabbits. Rings from hypercholesterolaemic NZW rabbits, however, did not significantly inhibit platelet aggregation when stimulated with carbachol. SIN-1 inhibited platelet aggregation in the presence of rings from either group of hypercholesterolaemic rabbits. 6. Hypercholesterolaemia induced by dietary modification induces changes in endothelial function which are characteristically different from those seen in genetically hypercholesterolaemic rabbits. It appears that dietary-induced hypercholesterolaemia primarily decreases NO release from the endothelium, while in genetically-induced hypercholesterolaemic vessel rings NO is released but there is a decreased responsiveness of the vascular smooth muscle cells to NO. This may reflect differences in the age and severity of the atherosclerotic lesions in the two groups of rabbits.     

Calcium-dependent and -independent interactions of the calmodulin-binding domain of cyclic nucleotide phosphodiesterase with calmodulin

The ubiquitous Ca2+-binding regulatory protein calmodulin (CaM) binds and activates a wide range of regulatory enzymes. The binding is usually dependent on the binding of Ca2+ to CaM; however, some target proteins interact with CaM in a calcium-independent manner. In this work, we have studied the interactions between CaM and a 20-residue synthetic peptide encompassing the major calmodulin-binding domain of cyclic nucleotide phosphodiesterase (PDE1A2). The binding was studied in the absence and presence of Ca2+ by far-UV and near-UV circular dichroism, fluorescence, and infrared spectroscopy. In addition, two-dimensional heteronuclear NMR studies with 13C-methyl-Met-CaM and uniformly 15N-labeled CaM were performed. Competition assays with smooth muscle myosin light chain kinase revealed a Kd of 224 nM for peptide binding to Ca2+-CaM, while binding of the peptide to apo-CaM is weaker. The peptide binds with an alpha-helical structure to both lobes of Ca2+-saturated CaM, and the single Trp residue is firmly anchored into the C-terminal lobe of CaM. In contrast, the Trp residue plays a minor role in the binding to the apo-protein. Moreover, when bound to apo-CaM, the PDE peptide is only partially helical, and it interacts solely with the C-terminal lobe of CaM. These results show that the Ca2+-induced activation of PDE involves a significant change in the structure and positioning of the CaM-bound PDE peptide domain.     

Giant sertoli cell adenoma in testicular feminization syndrome

An extremely large Sertoli cell adenoma discovered incidentally in an elderly phenotypically femal patient with testicular feminization syndrome is reported. The patient is alive 3 years following removal of the tumor.     

A multifactor analysis of growth in the rat epididymal fat pad

Adipose tissue is known to consist of at least two compartments, the adipocytes and the non-lipid filled cells. During normal growth and development of the rat epididymal fat pad, these two compartments changed in different manners. From 12 to 35 days of age, the DNA contained in both compartments increased linearly, indicative of hyperplastic growth. From 35 to 70 days of age, the DNA in the non-lipid filled cells continued to increase linearly; DNA in the adipocyte fraction increased more slowly. From 70 to 182 days of age, DNA accretion continued in the non-lipid filled cells while remaining unchanged in adipocytes. From 35 to 70 days of age, an abrupt change in the rate of tissue lipid accumulation occurred, shown both by a tripling of fat cell size and a markedly increased slope in the accumulation of lipid per pad. These data confirm that adipose tissue growth proceeds as suggested by radioactive thymidine incorporation studies and further suggest that a critical period for the onset of lipid filling may begin around 35 days of age.