Gastric trichobezoar in a banner-tailed kangaroo rat (Dipodomys spectabilis)

A male, wild-caught kangaroo rat developed anorexia and wasting. The animal was euthanized and a gastric trichobezoar found at necropsy. The paucity of information regarding the clinical medicine of this species is a hindrance to those charged with the care of kangaroo rats. Gastric trichobezoar should be considered as a differential diagnosis in cases of anorexia in kangaroo rats.     

Determination of naringenin and its glucuronide conjugate in rat plasma and brain tissue by high-performance liquid chromatography

An isocratic high-performance liquid chromatographic method with ultraviolet detection was utilized for the investigation of the pharmacokinetics of naringenin and its glucuronide conjugate in rat plasma and brain tissue. Plasma and brain tissue were deproteinized by acetonitrile, then centrifuged for sample clean-up. The drugs were separated by a reversed-phase C18 column with a mobile phase consisting of acetonitrile-orthophosphoric acid solution (pH 2.5-2.8) (36:64, v/v). The detection limits of naringenin in rat plasma and brain tissue were 50 ng/ml and 0.4 microg/g, respectively. The glucuronide conjugate of naringenin was evaluated by the deconjugated enzyme beta-glucuronidase. The naringenin conjugation ratios in rat plasma and brain tissue were 0.86 and 0.22, respectively, 10 min after naringenin (20 mg/kg, i.v.) administration. The mean naringenin conjugation ratio in plasma was approximately four fold that in brain tissue.     

A conundrum in molecular toxicology: molecular and biological changes during neoplastic transformation of human cells

The process of multistage carcinogenesis lends itself to the concept that the effects of carcinogens are mediated through dose-related, multi-hit, linear changes. Multiple in vitro model systems have been developed that are designed to examine the cellular changes associated with the progression of cells through the different stages in the process; however, these systems may have inherent limitations due to the cell lines used for these studies, the manner of assessing the effects of the carcinogens, and the subsequent growth and differentiation of the exposed cells. Each of these variables results in increasing levels of uncertainty relative to the correlation of the events with the actual process of human tumor development. Therefore, the prediction of the ultimate effect of any carcinogen is difficult. Moreover, relationships between individual biological endpoints resulting from carcinogen treatment appear at best to be approximations. The presence of an activated carcinogen inside the cell can give rise to multiple outcomes, only some of which may be critical events. For example, site-specific modification of the 12th and 13th codons of H-ras is different than that in the adjacent 14th and 15th codons. It is interesting to speculate what effect these differences might have on a biological outcome, e.g., transformation to anchorage-independent growth. The use of different model systems to examine the effects of activated carcinogens also creates additional problems. Comparisons of in vitro transformed cells with similar cells isolated from human tumors indicate that the culture environment appears to influence the expression of a particular phenotype, in that human tumor cells in culture express many of the same parameters as those found in cells transformed with carcinogens in vitro. If the process of transformation is linear, then less aggressive phenotypes should progress to a more aggressive transformed stage. However, in carcinogen-transformed human cells, the populations exhibit phenotypic diversity in that many of the transformed cells differentiate and fail to continue to divide in culture. Historically, we have assumed only a limited role for epigenetic modulation of molecular changes that occur during progression; however, our data suggest quite strongly that nonmalignant tumor populations can be converted to a more malignant phenotype without additional mutations taking place and, conversely, malignant populations can be downregulated to a nontumorigenic phenotype. Tumor cell plasticity is not only a fundamental characteristic of diverse types of human tumors, but also appears as an integral characteristic of carcinogen-transformed cells in vitro.     

Range of motion and complications after postburn heterotopic bone excision about the elbow

OBJECTIVE: To review the results of surgical management of heterotopic ossification about the elbow in burned patients. DESIGN: Retrospective analysis with long-term patient follow-up. MATERIALS AND METHODS: Eleven patients with 16 elbows requiring surgery were admitted between January 1, 1982 and December 31, 1993. A posterior approach to the elbow with release of the encased ulnar nerve +/- anterior transposition and transolecranon osteotomy to access extensive bone formation in the olecranon fossa was employed. Eight patients (11 elbows) were available for long-term follow-up conducted at mean 50 +/- 13 months after surgery. Long-term follow-up consisted of measurement of range of elbow motion, as well as clinical assessment of ulnar nerve function. MAIN RESULTS: For the 11 elbows examined postoperatively, the mean range of motion preoperatively in flexion-extension was 11 degrees +/- 5 degrees compared to 89 degrees +/- 12 degrees postoperatively (p < 0.001). Three patients with poor long-term results had ankylosis of the joint preoperatively. Of four patients with ulnar nerve paresis preoperatively, none had ulnar nerve dysfunction at follow-up. Of 16 elbows operated on, four (25%) had postoperative complications. Two suffered soft-tissue breakdown with hardware exposure requiring abdominal flap closure, one early failure of olecranon fixation, and one late infected hardware. CONCLUSIONS: Surgery for both limited range of motion as well as ulnar nerve compression is effective in cases of heterotopic ossification about the elbows of burned patients. Early operative intervention is indicated in progressive disease, particularly ulnar nerve palsy, if soft-tissue quality is adequate. Complications with 25% of elbows suggest that use of olecranon osteotomy for joint access may warrant review.     

Haemosuccus pancreaticus as a rare initial manifestation of chronic pancreatitis

Twenty-seven painful knee replacements were evaluated arthroscopically. The diagnostic and therapeutic value of these arthroscopic procedures was studied retrospectively. In 5 of the 27 cases, the arthroscopy revealed no diagnosis for the pain. Some form of arthroscopic treatment was performed in 20 cases; in 6 of these 20 cases, however, the treatment did not reduce the pain. Based on these findings, we conclude that the indications for arthroscopic evaluation and treatment of painful knee prostheses are limited.     

One hundred years of orthopedics in the Netherlands. VIII. Pediatric orthopedics

Orthopaedic disorders in children differ in type from those in adults: most frequent are congenital anomalies and disorders of growth and development. The special nature and relative rarity of these conditions justify the separate development of this branch of the discipline. Fractures almost always heal normally after closed reduction and immobilization in a plaster cast; fractures close to epiphyseal discs and in joints require special attention. Slipping of the upper femoral epiphysis necessitates surgical fixation of the epiphysis. Benign bone tumours occur relatively often and mostly require no surgical intervention. The prognosis of solid malignant bone tumours has improved since the introduction of (neo)adjuvant chemotherapy and limb-sparing surgery. In case of difference in leg length, the length of both legs is predicted with the aid of roentgenological measurements. Inhibition of the growth of the longer leg gives rise to fewer complications than lengthening of the short leg. The essence of the treatment of growth disorders due to abnormal ossification of the cartilage is to monitor the natural repair process and to intervene if permanent malformation threatens.     

A naturally occurring mutation in Fc gamma RIIA: a Q to K127 change confers unique IgG binding properties to the R131 allelic form of the receptor

Fc gamma RIIa is widely expressed on hematopoietic cells. There are two known allelic polymorphic forms of Fc gamma RIIa, Fc gamma RIIa-R131 and Fc gamma RIIa-H131, which differ in the amino acid at position 131 in the second lg-like domain. In contrast to Fc gamma RIIa-R131, Fc gamma RIIa-H131 binds hlgG2 but not mIgG1, and this differential binding has clinical implications for host defense, autoimmune disease, immunohematologic disease, and response to therapeutic monoclonal antibodies. We identified a novel Fc gamma RIIA genotype in a healthy individual homozygous for Fc gamma RIIA R/R131 in whom a C to A substitution at codon 127 changes glutamine (Q) to lysine (K) in one of the two Fc gamma RIIA genes. This individual's homozygosity for Fc gamma RIIA-R/R131 leads to the prediction that the receptors on her cells would not bind hIgG2. Monocyte and neutrophil phagocytosis of hIgG2-opsonized erythrocytes was significantly higher (P < .05) for cells from this K/Q127, R/R131 individual than for Q/Q127, R/R131 donors. Platelet aggregation stimulated by an mIgG1 anti-CD9 antibody in this individual was significantly different (P < .05) from Q/Q127, H/R131 and Q/Q127, H/H131 donors and similar to Q/Q127, R/R131. Our data show that the K127/R131 receptors have a unique phenotype, binding both hIgG2 and mIgG1. Further functionally significant mutations in human Fc gamma receptors and possible novel mechanisms for inherited differences in disease susceptibility should be sought with unbiased screening methods.     

A deoxyribonucleic acid-replication intermediate in the growing mosquito

The arrangement of 18-S rRNA and 28-S rRNA within their 40-S common precursor molecule (pre-rRNA) of Xenopus laevis was investigated by electron microscopic analysis of secondary structure of nascent pre-rRNA chains of oocytes, and by 5'-end analysis of 18-S rRNA and 28-S rRNA hybridized to the EcoRI fragment of rDNA cloned as plasmid pCD42. Secondary structure mapping of phenol-extracted RNA from nucleolar cores revealed complete pre-rRNA chains or molecules at various stages of processing and pre-rRNA molecules apparently lacking one end. In this latter group, which was regarded as representing nascent chains, more than 90% of the molecules had no 28-S rRNA REGION. This shows that the 28-S rRNA sequence is transcribed after the 18-S rRNA region and hence must be located nearer to the 3' end of the pre-rRNA molecule. For 5' end-group determination [3H]uridine-labelled 18-S rRNA and 28-S rRNA were hybridized, as fragments of about 200 nucleotides, to the plasmid pCD42 containing coding sequences for four-fifths of the 18-S rRNA sequence, the external transcribed spacer, the non-transcribed spacer and a tenth of the 28-S rRNA sequence. The RNA was recovered from the hybrids and analyzed for uridine 3',5'-bisphosphate (pUp) after alkaline hydrolysis. The pUp content of the hybridized 18-S rRNA fragments was 20-fold higher than in those of 28-S rRNA, THUS DEMONSTRATING THAT THE 5' END OF THE 18-S rRNA is located next to the external spacer region. From these results it is concluded that the 18-S rRNA is located close to the 5' end of the 40-S pre-rRNA molecule.