Isolated blunt liver trauma: is nonoperative treatment justified?

During the past 8 years 13 children with isolated blunt liver trauma were managed nonoperatively. All patients selected for this management were hemodynamically stable after initial resuscitation and were without signs of other associated intraabdominal injuries on ultrasonogram and/or computed tomography. Patients were observed in an intensive care unit for at least 48 hours with repeated clinical assessments, laboratory studies, and bed rest. One patient with type 3 injury was operated on 8 days after injury because of sudden intraperitoneal bleeding on ambulation. Five patients required blood transfusions of not more than 300 mL per patient. Laboratory values returned to normal from 7 to 21 days after injury. Resolution of hepatic injury on ultrasonogram took from 1 to 3 months. Complete bed rest was prescribed for at least 10 days depending on the type of injury, with restricted activities up to 3 months postinjury. No complications were seen in this series.     

Mapping the Von Hippel -- Lindau disease tumour suppressor gene: identification of germline deletions by pulsed field gel electrophoresis

Von Hlppel—Lindau (VHL) disease is a dominantly Inheritedfamillal cancer syndrome In which affected individuals havea greatly increased predisposition to the development of haemangloblastomasof the central nervous system and retina, renal cell carcinomaand phaeochromocytoma. The VHL gene has been mapped to chromosome3p25 -p26 by genetic linkage studies and we have previouslydemonstrated that the VHL gene is tightly linked to the D3S601locus (Zmax = 18.86 at     

Desensitization of macrophages to stimuli which induce secretion of superoxide anion. Down-regulation of receptors for phorbol myristate acetate

The ability of cultivated mouse peritoneal macrophages (M phi) to release superoxide anion (O-2) after repeated stimulation by phorbol myristate acetate (PMA) or serum-treated zymosan (STZ) has been studied. After a maximal first stimulus bacillus Calmette-Guérin (BCG)-activated M phi released high levels of O-2, 2-fold more than thioglycollate-elicited M phi and the response ceased within 4 h. Both populations either responded again to a second challenge or displayed a refractory state which varied in duration and selectivity. Desensitization by STZ pretreatment was transient and selective whereas PMA could render M phi refractory for 3 days to PMA alone or to both agents, depending on the amount of PMA used and the conditions of stimulation. PMA induced a selective loss of specific saturable receptors for [3H]phorbol dibutyrate, a closely related agent, and receptor activity recovered with the ability to release O-2. Loss of receptors did not account for concomitant loss of the response to STZ after nonselective deactivation. Such M phi were fully viable and able to endocytose various soluble and particulate ligands vigorously, but without stimulation of the hexose monophosphate shunt or release of O-2. Our studies indicate that M phi activities can be profoundly altered by prior stimulation, that specific receptors play a role in ligand-induced desensitization and that agents such as PMA can selectively eliminate the cells' ability to generate a second respiratory burst.     

The enzyme responsible for the respiratory burst in elicited guinea pig peritoneal macrophages

The enzymatic basis of the respiratory burst induced by phorbol myristate acetate in elicited peritoneal macrophages of the guinea-pig has been studied. The following evidence suggests that a membrane-bound oxidase that preferentially uses NADPH as substrate is the main enzyme responsible for activation of the oxidative metabolism: (1) The supernatant of postnuclear fractions of resting macrophages oxidises NADH and NADPH with formation of O. The activity with both substrates is very low and does not change in the supernatant obtained from activated cells. (2) The cell-free particles of resting macrophages also oxidise both NADH and NADPH with formation of O. The activity of the cell-free particles from activated macrophages does not change when NADH is the substrate. By contrast, the activity of the cell-free particles from activated cells is markedly increased when NADPH is the substrate. (3) In cell-free particles from activated macrophages the K_m for NADPH is about one order of magnitude lower than that for NADH and the V_max with NADPH is double that with NADH. (4) The NADPH oxidase of cell-free particles is insensitive to azide, cyanide, antimycin A and rotenone and is sensitive to the sulphydryl reagent PCMB. All these drugs have the same effect on the respiratory response of intact macrophages. (5) A direct correlation is found between the degree of activation of the respiratory metabolism of intact macrophages and the extent of activation of the NADPH oxidase. A new approach designed to measure the activity of the oxidase soon after the activation of the enzyme has taken place, shows that the NADPH oxidase can account for the respiratory burst of intact macrophages.     

Somatic von hippel-lindau mutation in clear cell papillary cystadenoma of the epididymis

Papillary cystadenoma of the epididymis is an uncommon benign lesion that may occur sporadically or as a manifestation of von Hippel—Lindau (VHL) disease. Neither immunohistochemical studies nor molecular genetic analyses of the VHL gene have been reported previously for this lesion. The authors describe two cases of clear cell papillary cystadenoma of the epididymis, both of which were initially confused with metastatic renal cell carcinoma. Both lesions showed positive immunohistochemical staining for low and intermediate molecular weight keratins (Cam 5.2 and AE1/AE3), EMA, vimentin, α₁-antitrypsin, and α₁-antichymotrypsin. Each was negative for CEA. Because clear cell papillary cystadenoma is similar to renal cell carcinoma histologically, and because both occur as components of the von Hippel—Lindau disease complex, the authors analyzed both cases for the presence of mutations in the VHL gene. A somatic VHL gene mutation was detected in one of the two tumors by polymerase chain reaction followed by single-strand conformation polymorphism analysis. Direct sequencing revealed a cytosine to thymine transition at nucleotide 694, resulting in the replacement of an arginine with a stop codon after the sixth amino acid of exon 3. As the VHL gene is believed to function as a tumor suppressor gene, VHL gene mutations may play a role in the initiation of tumorigenesis in sporadic cystadenomas of the epididymis.     

Generation of superoxide anion by alveolar macrophages in sarcoidosis: evidence for the activation of the oxygen metabolism in patients with high-intensity alveolitis.

We studied superoxide anion (O2) generation by alveolar macrophages (AM) isolated from bronchoalveolar lavages (BAL) of patients with sarcoidosis, and assayed immediately after the isolation or after maintenance in culture for 2 days. In assays of cells freshly isolated from BAL, AM of patients with active sarcoidosis with a high-intensity lymphocytic alveolitis produced more O2- in response to phorbol myristate acetate than AM of patients with inactive sarcoidosis. Also, after 2 days of cultivation sarcoid AM were heterogeneous in their capability to metabolize oxygen, although both AM of active and inactive sarcoid patients produced higher amounts of O2- than AM of healthy subjects. In vitro treatment with recombinant interferon-gamma (rIFN-gamma) caused an enhancement of the capability of AM of inactive sarcoid patients to produce O2- in response to PMA. AM of patients with active sarcoidosis did not respond to rIFN-gamma when they already produced O2- vigorously. However, they became sensitive to the activating effect of rIFN-gamma after the down-modulation of their capability to produce O2-, that occurred upon prolonged cultivation. Monocytes isolated from blood of sarcoid patients and assayed immediately or after different times of cultivation did not produce more O2- than control monocytes and monocyte-derived macrophages, thus indicating that the activation of AM in sarcoidosis is likely a local phenomenon. These studies strengthen the notion that T lymphocyte-macrophage interaction is a critical event in the pathogenesis of sarcoidosis and establish that the enhanced capability to metabolize oxygen to highly reactive intermediates by AM is one of the consequence of this interaction.     

CD40 expression by gingival fibroblasts: correlation of phenotype with function

CD40, a member of the tumor necrosis factor-alpha receptor family, is constitutively expressed by cells of hematopoietic and non- hematopoietic origin, including fibroblasts. Signaling through this receptor molecule regulates inflammatory cytokine secretion by many cell types. Based on the recently described cytokine secretory heterogeneity of fibroblast cell subsets, we hypothesized that secretion of inflammatory cytokines by gingival fibroblast cultures may be dictated by the existence of differential proportions of cytokine- secreting subpopulations which express high levels of CD40. After examining a large number of gingival fibroblast (GF) cultures we find that the frequency of IL-6- and IL-8-secreting cells mirrors the frequency of cells expressing high levels of CD40 in these cultures. In addition, we demonstrate a direct functional relationship between CD40 expression and IL-6 or IL-8 secretion by showing that ligation of this molecule on GF, and CD40+ fibroblast subsets in particular, up- regulates secretion of these cytokines in vitro.      

Molecular analysis of de novo germline mutations in the von Hippel-Lindau disease gene

VHL disease is a dominantly inherited familial cancer syndromewith variable expression and age-dependent penetrance. The diagnosisof isolated cases is often delayed compared with familial cases,and estimates of the new mutation rate have varied more than20-fold. To investigate the frequency and origin of de novoVHL gene mutations we have analysed: (i) families with identicalmutations to determine if there is a common haplotype, and (ii)apparent new mutation cases to determine whether the clinicaldiagnosis of such cases is reliable and to define the parentalorigin of de novo VHL gene mutations. Haplotyping of 12 VHLmutations occurring in two or more families (total 42 kindreds)revealed that for most mutations there was no evidence of afounder effect. A marked bias for a paternal origin of new mutationshas been reported in other familial cancer syndromes such asneurofibromatosis type 1 (NF1), multiple endocrine neoplasia(MEN) 2B and bilateral retinoblastoma, but it is unclear whetherthis bias results from a greater susceptibility for mutagenesisduring male gametogenesis because of the larger number of celldivisions compared with that in oogenesis, or from genomic imprintingeffects. Analysis of 13 de novo VHL mutations in which the parentof origin could be established, showed no evidence for a biasfor a paternal origin (seven paternal, six maternal), and differedsignificantly from that reported in NF1, MEN2B and bilateralretinoblastoma. This result demonstrates that an increased susceptibilityto paternal allele mutation is not a universal finding in autosomalgenetic diseases and that the origin of new mutations may beinfluenced by both genomic imprinting effects and the increasednumber of cell divisions in spermatogenesis compared with oogenesis.