Men, medicine and machines

PURPOSE: To examine the management and possible causes of primary valve malfunction of the Krupin eye valve with disk. METHODS: The authors reviewed the results of 113 patients undergoing implantation of the Krupin eye valve with disk and identified eight patients with primary valve malfunction requiring surgical revision. RESULTS: Valve revision involved manipulation (n = 1 case), explantation of the malfunctioning valve and implantation of a new valve (n = 2), and amputation of the valve (n = 5). Six of eight patients had final intraocular pressures of < 21 mmHg on one or no medications at a mean interval of 15.9 months (range 5-36) after surgical revision. Transient postoperative hypotony was noted in three patients and chronic hypotony with loss of light perception in one patient. One explanted valve was examined and found to have partially fused leaflets. CONCLUSIONS: Surgical revision in cases of primary valve malfunction of the Krupin eye valve with disk may be accomplished relatively safely with an acceptable level of postoperative complications. The etiology of primary valve malfunction may be related to the sterilization process and prolonged storage before implantation.     

Interferon-gamma activates the oxidative killing of Candida albicans by human granulocytes

The sequence proline-proline-glycine-proline is highly conserved in cytochrome P450 families 1 and 2, and similar proline rich sequences are found in other cytochromes P450. Since this sequence immediately follows the NH2-terminal hydrophobic membrane insertion signal, it potentially could function as a signal either for retention of cytochrome P450 in the endoplasmic reticulum or for its correct orientation in the membrane. To test this possibility, DNA sequence coding for this tetrapeptide was deleted from cytochrome P450 2C2 cDNA. Translation of the mutated mRNA in a reticulocyte cell-free system containing canine microsomal membranes resulted in the insertion of the protein into the membrane with a topology indistinguishable from that of normal cytochrome P450 2C2. The mutated protein was expressed in COS1 cells and its distribution, assayed by immunofluorescence, was similar to that of cytochrome P450 2C2. Furthermore, if a short peptide containing a potential glycosylation site was fused to the N-terminus of the mutant protein, the new hybrid protein was glycosylated in COS1 cells and the carbohydrate moiety remained sensitive to cleavage by endoglycosidase H. These results indicate that the protein was inserted and retained in the endoplasmic reticulum membrane. Pulse-chase studies showed that the mutated protein was degraded about four times as fast as cytochrome P450 2C2. In contrast to cytochrome P450 2C2, no (omega-1) hydroxylase activity was detected in COS1 cells expressing the mutated protein at similar steady-state levels as the wild-type protein. These results indicate that, although the conserved PPGP tetrapeptide is not required for cellular localization of cytochrome P450 in the endoplasmic reticulum membrane, its deletion decreases the stability of the protein and abolishes enzymatic activity.     

A little less sodium is not without hazard

Surgical thrombectomy is not a rational approach to neonatal renal vein thrombosis since the occlusion mainly involves intrarenal branches rather than the main renal vein, which is even patent in some instances. Conservative management combines supportive therapy for renal failure and systemic hypertension, if needed, and either heparin or thrombolytic agents. Streptokinase has proven difficult to handle in neonates and should not be used. Urokinase has been used in 18 patients but results are difficult to interpret because these cases occurred over an 18-year period. Plasminogen tissue activator, the latest thrombolytic agent developed, has been used in few pediatric patients. An international task force is currently studying whether or not a randomized study is warranted to provide data for standardizing thrombolytic therapy in pediatric renal vein thrombosis.     

Fetus-in-fetu with malignant recurrence

Fetus-in-fetu is an unusual condition in which a vertebrate fetus is enclosed within the abdomen of another fetus. These occurrences are usually benign. This report describes an instance of malignant recurrence after resection of a fetus-in-fetu.     

RNA movement between the nucleus and the cytoplasm

The past year has seen significant advances in our understanding of the mechanism of RNA movement between the nucleus and the cytoplasm. The emerging view is that proteins bind to and escort RNAs to their proper subcellular location. The discovery of peptide signals that target nuclear export and the identification of novel protein mediators of RNA export are examples of significant recent discoveries.     

Stability of proximal femoral grafts in canine hip arthroplasty

In a canine model, the fixation stability of a prosthesis and proximal bone graft composite were measured relative to the distal femur. One group had the prosthesis graft composite cemented into the distal femur. The second group had the prosthesis graft composite press fit into the distal femur for biologic ingrowth. Displacements of the proximal femoral grafts relative to the host bone in each group were measured after ex vivo (acute with graft) implantation and 4 months after implantation. A third group with no osteotomy (acute intact) simulated perfect graft to host bone union. Relative displacements representing 6 degrees freedom (translation and rotation) were calculated from the displacement values measured by 9 eddy current transducers. Measurements of displacement were used to test the hypothesis that distal press fit fixation equals distal cement fixation at 4 months after implantation. In all cases the measured translations and rotations of the graft to implant construct were small and of a magnitude that should encourage bone ingrowth (< 0.05 mm and < 0.1 degree, respectively). The stability of the press fit group at 4 months was not significantly different from the cemented group in axial and transverse displacement during axial and transverse loading, respectively. There was no difference in stabilities at 4 months between distal press fit and cemented fixation in hip replacements requiring a proximal femoral graft.     

Induced abortion in a Swiss canton from 1990 to 1993: implications for epidemiological surveillance

BACKGROUND: To describe abortion utilization in the Canton of Vaud (Switzerland) and to identify desirable changes in the data collection system to improve the epidemiologic monitoring METHODS: Retrospective survey of the 5600 abortion requests to the Canton Health Authority for resident women between 1990 and 1993. RESULTS: Nine women out of 1000 residents requested an abortion, but the abortion rate was higher among women of foreign origin compared to Swiss women (17/1000 vs. 6/1000, p < 0.0001). The proportion of terminated recognized conceptions was 127/1000, and the ratio of IVG to livebirths was 0.18. The abortion rate was lower during adolescence (6/1000) or after 40 years of age (1.8/1000), whereas the proportion of terminated conceptions was highest at these ages (527/1000 and 312/1000). Abortion utilization in Canton of Vaud is among the lowest. CONCLUSIONS: Although these indicators do reflect a satisfactory accessibility and use of family planning services, improvements could be made. A better knowledge of the causes (motives, contraceptive method, reproductive history) and of the consequences of abortion (psycho-social implications, medical complications) would allow to design more focused prevention strategies and to fit health services to current needs. Updating the 1942 Swiss legislation is also desirable.     

Morphological and functional polymorphism within clonal thyroid nodules

Thirty-nine thyroid nodules, removed because of recent growth, were analyzed morphologically by serial histological sections for the classical histomorphological hallmarks of follicular cell replication and for immunohistochemically demonstrable overexpression of the growth-associated ras-gene product p21ras. Clonal analysis was performed using the highly informative probe M27 beta that detects polymorphisms on the locus DXS255 of the X-chromosome. Twenty-four nodules were of clonal and 15 nodules were of poly-clonal origin. Only 3 out of the 24 clonal nodules were histomorphologically uniform. In all others, the structural hallmarks of active growth and the P21ras growth-marker expression were remarkably heterogeneous throughout the tumors. There were no histomorphological characteristics distinguishing these clonal tumors from polyclonal nodules. Even if a clonal thyroid tumor may be originally homogeneous in respect to the parameters studied here, mechanisms must exist that create wide heterogeneity of growth and of morphogenetic potential among the individual follicular cells during further expansion of the nodule. Thus, clonal nodules are much more common in nodular goiters than hitherto assumed on grounds of the classical morphological criteria. The diagnosis of a true monoclonal nodule can no longer rely on morphological and functional criteria alone but requires molecular or cytogenetic analysis of clonality.