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Biomedical subjects

D Lew

Publications and source records attributed to D Lew.

At least 55 records · Page 3Linked to original sources

The use of tissue expanders in the correction of avulsive injuries of the mandible: report of two cases.

Two cases illustrating successful use of tissue expanders to correct both soft and bony defects of the facial region are presented. The tissue expanders allow the development of a flap that has the same color and texture as the lost tissue. It also precludes the need of a distantly developed flap with its associated morbidity. The highly vascular fibrous capsule developed around the expander provides the advantage of initially greater blood supply and increased bulk for coverage of a bone graft. Although this is temporary in nature, it provides a desirable receptor bed during the critical period of bony union. The ready availability of adjacent tissue, the esthetic considerations, and the comparative reduction in morbidity when compared with use of distant flaps makes the use of tissue expanders an attractive technique in maxillofacial reconstruction.

Bone Transplantation

Comparison of immunological methods for diagnosis of pneumococcal pneumonia in biological fluids.

Five immunological tests were evaluated for their ability to detect Streptococcus pneumoniae antigen in serum and urine simultaneously as a means of rapid diagnosis in 40 patients with bacteremic or non-bacteremic pneumococcal pneumonia or pneumonia with other etiologies. Serum and urine were screened in parallel with counterimmunoelectrophoresis (CIE), two commercial latex agglutination kits - the Slidex pneumokit (LA-SPK) and the Bactigen Streptococcus pneumoniae kit (LA-Bac) - the coagglutination Phadebact Pneumococcus test (CoA) and a newly developed enzyme-linked immunosorbent assay (ELISA) containing the immunoglobulin G fraction from rabbit pneumococcal antiserum. The detection rate for accumulated serum in bacteremic patients was 18% for LA-Bac, 24% for CIE, 47% for LA-SPK and CoA and 76% for ELISA, whereas antigenuria was present in only 29% for LA-SPK, 24% for CIE, 19% for CoA, 14% for LA-Bac and 5% for ELISA. Detection by ELISA of pneumococcal antigen in severely ill patients can predict bacteremia and rapidly confirm the diagnosis of pneumococcal pneumonia if sputum and results of blood cultures are not available.

Agglutination Tests

The use of freeze-dried rib and hydroxylapatite in the treatment of a fracture occurring in a patient with familial facial osteodystrophy.

The treatment of repeated pathologic fractures of the mandible has long taxed the ingenuity of surgeons. The complexity of the problem increases with the recognition of a metabolic defect that renders the facial bones hypoplastic. In the case presented, a tentative diagnosis of familial facial osteodystrophy was made at the National Institutes of Health. Since that time, the patient has undergone autogenous onlay grafting, which has completely resorbed. Because of continuous resorption, a number of pathologic fractures have occurred. The most recent fracture was treated by means of a freeze-dried rib, which acted as a floor and as a splint to the fracture site. Hydroxylapatite and a marrow mixture were placed on the floor to gain height, strength, and durability. Subsequently, hydroxylapatite augmentation was performed to gain a more anatomic alveolar ridge. The patient's 12-month follow-up has shown the mandible to be intact with no noticeable change in either vertical or horizontal dimensions.

Adult

False aneurysm complicating orthognathic surgery.

A case of a pseudoaneurysm secondary to bleeding which occurred during an intraoral vertical osteotomy of the mandible is presented. The bleeding was thought to be controlled by packing, but ultimately a pseudoaneurysm formed. Arteriography was used to diagnose the lesion and embolization to treat it. Duplex ultrasound played a complimentary role in the diagnosis, and in monitoring the therapeutic course.

Adolescent

Early termination of a prospective, randomized trial comparing teicoplanin and flucloxacillin for treating severe staphylococcal infections.

In a prospective, randomized trial, teicoplanin (at a 400-mg intravenous loading dose followed by 200 mg/day intravenously or intramuscularly) was compared with flucloxacillin (8 g/day) in patients with severe staphylococcal infections. Teicoplanin proved unsatisfactory for the following reasons: failures or relapses were more frequent in the teicoplanin group, and blood levels were difficult to predict and tended to be low 24 hr after the loading dose. Future trials with this agent should use much-higher doses.

Adult

Role of bacterial exopolymers and host factors on adherence and phagocytosis of Staphylococcus aureus in foreign body infection.

Using a previously developed guinea pig model of foreign body infection, we examined ultrastructural and functional surface alterations of Staphylococcus aureus strain Wood 46 during the early phase of infection. Exopolymer-free bacteria were prepared and inoculated into subcutaneously implanted tissue cages. After three hours, the bacteria showed abundant capsular and intercellular exopolymers, which were visualized by transmission electron microscopy. Exopolymers were also produced by S. aureus exposed in electron microscopy. Exopolymers were also produced by S. aureus exposed in vitro to fluid from the tissue cage. In contrast, human serum albumin prevented exopolymer production by S. aureus. The influence of exopolymers on the susceptibility of S. aureus to ingestion and phagocytic killing by neutrophils was tested in vitro and found to be negligible. Furthermore, adherence of S. aureus to fibronectin-coated surfaces was unaffected by the presence or absence of exopolymers. Thus, in our experimental model, exopolymers are produced early during the onset of infection, but they have little impact on adherence and phagocytosis.

Animals

The Xenopus laevis estrogen receptor: sequence homology with human and avian receptors and identification of multiple estrogen receptor messenger ribonucleic acids.

We have isolated and sequenced a cDNA clone encompassing the entire protein coding region of the Xenopus laevis estrogen receptor (xER). The Xenopus ER, the first steroid hormone receptor to be sequenced from a cold-blooded organism, exhibits two regions of striking amino acid homology with the human and avian ERs. In the putative DNA binding region, the amino acid sequence of the xER differs from those of the human and avian ERs at only one of 83 amino acids. The putative hormone binding region contains 44 and 46 amino acid blocks in which the sequence is identical in the Xenopus and human ERs. Blot hybridizations of Xenopus liver RNA suggest that the xER is encoded by four mRNAs with lengths of approximately 9, 6.5, 2.8, and 2.5 kilobases. In contrast, hybridization of human RNA to a human ER cDNA clone reveals only a single major ER RNA, approximately 6.7 kilobases in length.

Amino Acid Sequence

Autogenous rib graft-hydroxylapatite augmentation of the severely atrophic mandible: preliminary report.

Traditional transoral rib grafts were combined with particulate hydroxylapatite (HA) for augmentation in four patients who had advanced alveolar atrophy or cortical resection of the mandible. Follow-up evaluation for up to 18 months revealed restoration of mandibular morphology, with good prosthetic function and insignificant resorption. No infection or graft loss was observed, in spite of wound dehiscence in two of the four patients, possibly due to the placement of the HA lateral and superior to the rib grafts.

Aged

Sphenoid sinusitis.

We review our clinical experience with infectious sphenoid sinusitis in an effort to characterize the clinical presentation, bacteriology and associated severe complications of this frequently misdiagnosed infection.

Adult