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Biomedical subjects

C R Perry

Publications and source records attributed to C R Perry.

At least 19 recordsLinked to original sources
PubMed1995

Distal femur as a donor site of autogenous cancellous bone graft.

We performed a prospective clinical study and a cadaveric study to evaluate the morbidity associated with harvesting cancellous bone from the distal femoral metaphysis for use in the lower extremity. Thirty patients underwent harvest of distal femoral cancellous bone: 13 for acute trauma and 17 for reconstructive procedures. The distal femoral condyle is approached through a 6-cm midlateral, longitudinal incision. A small cortical window is created, bone graft is harvested, and the cortical window is replaced. All patients were kept nonweight bearing on the extremity for a minimum of 6 weeks. Patients were followed for an average of 10 months (range 3-32 months) and no patient was lost to follow-up before allowing full weight bearing. There were no donor site would or neurovascular problems and no femur fractures. A cadaveric study was also performed in which bone was harvested from the distal femur, the bone was quantified, and the knees were tested in compression (axial loading). The bone-harvested knees failed in the same load range as the contralateral control knees did. The distal femoral metaphysis has many advantages compared with the iliac crest in cases when cancellous bone is needed for the lower extremity. Harvesting distal femoral bone is associated with little morbidity if performed correctly, and if the patient remains nonweight bearing for 6 weeks.

Adult↗
PubMed1994

Bacterial resistance mechanisms as therapeutic targets.

In the 50 years since antimicrobial agents were first introduced, bacteria have acquired a wide variety of mechanisms which have enabled them to resist the effects of these drugs. One way of overcoming this problem is to administer an antibiotic with an agent which counteracts the mechanism of resistance to that antibiotic; an example of such an approach which has already been successfully implemented is the combination of a beta-lactam antibiotic with a beta-lactamase inhibitor. This review describes antibiotic resistance mechanisms which might lend themselves to an inhibitor approach and the potential therapeutic applications of such a strategy.

Bacteria↗
PubMed1994

Intracapsular fractures of the proximal femur.

Intracapsular fractures in the geriatric population are the result of progressive osteopenia, resulting in weakening of the bone. Minor trauma results in fracture of the weakened femoral neck. Most commonly, this process occurs in patients whose osteopenia is secondary to senile osteoporosis. The fact that the femur is osteopenic means that fixation may be difficult to achieve. However, reduction is relatively easy to obtain because of the absence of communication and the minimal displacement.

Aged↗
PubMed1993

The structure of laccase protein and its synthesis by the commercial mushroom Agaricus bisporus.

Agaricus bisporus secretes abundant laccase activity into the medium during mycelial growth. SDS-PAGE analysis of extracellular laccase protein, purified from compost extract, showed a predominant band of 65 kDa molecular mass, together with lesser amounts of smaller polypeptides. The main polypeptide was purified electrophoretically. Amino acid sequence analysis of the N-terminal region of the main polypeptide was used to specify the sequence of a 15-residue chemically synthesized peptide (N-terminal peptide). Rabbit antibodies were raised against pure laccase, electrophoretically purified main polypeptide and the synthetic N-terminal peptide. Electrophoretically purified main polypeptide antibody was further purified by affinity chromatography on laccase-CNBr-Sepharose. Western blot analysis showed that the antigenic behaviour of laccase in compost extract, culture filtrate from malt-extract culture, and the purified enzyme from both sources, differed. The patterns of bands revealed are most simply explained by generation of (proteolytically) partially cleaved enzyme molecules in the culture medium, possibly combined with differences in extent of glycosylation. [35S]Methionine incorporation and immunoprecipitation were used to follow laccase synthesis in cultures grown on malt extract. After short-term labelling, a single polypeptide of 68 kDa apparent molecular mass was immunoprecipitated from both mycelial extracts and the culture medium. When poly(A)-containing RNA from malt-extract-grown mycelium was translated in vitro in rabbit reticulocyte lysate, a single polypeptide of about 57 kDa molecular mass was immunoprecipitated, consistent with the previously measured carbohydrate content of 15% for the pure enzyme. After treatment with N-glycanase, the polypeptide showed an increase in mobility during SDS-PAGE consistent with a reduction in molecular mass of about 5 kDa, indicating about equal amounts of N- and O-linked carbohydrate. C-terminal labelling of pure laccase was attempted by transpeptidation with carboxypeptidase Y. Although some minor bands were labelled, the main polypeptide was not, indicating that the C-terminus of the enzyme may be blocked.

Agaricus↗
PubMed1993

Identification of two laccase genes in the cultivated mushroom Agaricus bisporus.

A cDNA library was constructed in lambda gt11 using mRNA from 11-d-old mycelium of Agaricus bisporus. Three clones containing laccase sequence were identified using an affinity-purified anti-laccase antibody. From one of these clones, a 333 bp sequence was used to identify further cDNA clones (including one which is close to full length) and a genomic clone. The coding sequences found were of two similar but not identical versions with differences at 36 out of 520 residues of deduced amino acid sequence. The laccase genes each encode a sequence expressed as a 2.3 kb mRNA, specifying a 520 residue polypeptide including a 19 amino acid residue signal peptide that is absent from the N terminus of the mature (extracellular) protein. The coding sequence of lcc1 is interrupted by 14 short introns. The lcc1 and lcc2 genes are not allelic as they do not segregate in uninucleate spores derived from a four-spored basidium. Comparison of the deduced amino acid sequences with that of the other fungal laccases that have been cloned, and with the very similar ascorbate oxidases from higher plants shows that whilst some sequence is absolutely conserved at and around the amino acid residues involved in copper binding, the overall sequence similarities are low.

Agaricus↗
PubMed1993

High-level mupirocin resistance in Staphylococcus aureus: evidence for two distinct isoleucyl-tRNA synthetases.

Mupirocin resistance in Staphylococcus aureus results from changes in the target enzyme, isoleucyl-tRNA synthetase (IRS). Twelve strains of S. aureus comprising four susceptible (MICs < or = 4 micrograms/ml), four intermediate level-resistant (MICs between 8 and 256 micrograms/ml), and four highly resistant (MICs > or = 512 micrograms/ml) isolates were examined for their IRS content and the presence of a gene known to encode high-level mupirocin resistance. Ion-exchange chromatography of cell extracts showed a single IRS active peak in mupirocin-susceptible strains, with 50% inhibitory concentrations (IC50s) of 0.7 to 3.0 ng of mupirocin per ml. In strains showing intermediate mupirocin resistance, similar single IRS activity peaks were observed, but these were less sensitive to inhibition, and the mupirocin IC50s for them were 19 to 43 ng/ml. Strains that were highly resistant to mupirocin displayed two distinct peaks; one was similar to that found with susceptible strains (IC50, 0.9 to 2.5 ng/ml), but an additional peak with an IC50 of 7,000 to 10,000 ng/ml was also observed. A strain cured of the plasmid encoding high-level mupirocin resistance lacked the resistant IRS peak. Restriction digests, produced by endonuclease NcoI, of total bacterial DNA isolated from the highly resistant strains hybridized with a mupirocin resistance gene probe, whereas DNA isolated from the intermediate level-resistant and susceptible strains did not. These results demonstrate that two different IRS enzymes were present in highly mupirocin-resistant S. aureus strains. In strains expressing intermediate levels of resistance, only a chromosomally encoded IRS which was inhibited less by mupirocin than IRS from fully susceptible strains was detected.

Base Sequence↗
PubMed1992

Treatment of acutely infected arthroplasties with incision, drainage, and local antibiotics delivered via an implantable pump.

Twelve patients with acutely (symptomatic less than ten weeks) infected arthroplasties were treated with minimal debridement and intraarticular antibiotic, amikacin, delivered via an implantable pump. The infection was suppressed in ten cases. Intraarticular levels of amikacin were obtained in eight cases. These levels ranged from greater than 150 micrograms/ml to 1688 micrograms/ml. The systemic level of amikacin remained below 10 micrograms/ml in all but one case. Duration of hospitalization averaged 19 days. There were no significant toxic side effects to amikacin.

Acute Disease↗
PubMed1992

Basic principles and clinical uses of screws and bolts.

The orthopaedic surgeon uses screws for interfragmentary fixation, fastening soft tissue to bone, or holding plates or nails to bone. The most common function of screws is to fix bone to bone. This article reviews the design parameters and types of screws used in orthopaedic surgery.

Bone Screws↗
PubMed1991

Local antibiotic delivery in the treatment of bone and joint infections.

Antibiotics can be delivered locally via an implantable pump to treat bone and joint infections. This is a completely closed system, and the pump is refilled percutaneously at intervals based on its flow rate. The use of this method is described in three specific clinical situations: (1) resistant osteomyelitis (patients with persistent infections despite previous therapy), (2) acutely infected arthroplasties (symptomatic for less than six weeks), and (3) chronically infected arthroplasties (patients infected more than six weeks). In all three clinical situations, hospitalization time was shortened, and high local and low systemic levels of antibiotic were obtained. There was only one incident of side effects to the antibiotic used. This method has been successful in obtaining long-term suppression of infection in 30 of 42 patients with resistant osteomyelitis, 30 of 37 patients with acutely infected arthroplasties, and seven of ten patients with chronically infected arthroplasties. The complication unique to this method of therapy is pump-site and catheter-site infections. This occurred in three patients with recalcitrant osteomyelitis and three patients with acutely infected arthroplasties.

Acute Disease↗
PubMed1991

Accuracy of cultures of material from swabbing of the superficial aspect of the wound and needle biopsy in the preoperative assessment of osteomyelitis.

The pathogens that were identified on cultures of material obtained by swabbing of the superficial aspect of the wound and needle biopsy were compared with those that were isolated from material that was obtained at débridement from sixty patients who had post-traumatic or postoperative osteomyelitis. The cultures of material that was obtained by superficial swabbing of the wound and needle biopsy were inadequate for prediction of the presence of aerobic organisms. Moreover, the failure to isolate anaerobes from the material obtained by needle biopsy did not rule out the presence of anaerobic organisms. Therefore, tissue for culture of aerobic and anaerobic organisms must be obtained during operative débridement in order to identify all pathogenic organisms. Fungi were isolated from the material obtained by biopsy in two patients. In addition, histological examination of the tissue obtained at biopsy led to the diagnosis of epidermoid carcinoma in two patients in whom this diagnosis had not been suspected before biopsy. Cultures were negative for mycobacteria in all patients. An additional ten patients who had a tibial non-union and latent osteomyelitis were studied. In nine of them, cultures of material obtained by needle biopsy showed no growth. Six of these nine patients had an exacerbation of the osteomyelitis after intramedullary nailing for the non-union. Therefore, the absence of growth of organisms from tissue obtained at needle biopsy does not rule out the possibility that osteomyelitis may be reactivated after intramedullary nailing with reaming.

Bacteria↗
PubMed1989

Transcondylar fractures of the distal humerus.

We classify transcondylar fractures of the distal humerus into four groups: undisplaced; simple displaced; T-type; and fracture dislocations (Posada's fracture). Our treatment of these fractures is based upon this classification. Undisplaced fractures are treated with immobilization. Displaced fractures are reduced and stabilized with internal fixation. Stabilization of these fractures is difficult because the distal fragments are small and a large portion of their surface is covered with articular cartilage. Transposition of the ulnar nerve allows us to use the cubital tunnel as a point for fixation. We found in our series of 11 patients that undisplaced fractures have the best prognosis. However, all of our patients lost elbow motion, particularly extension. Radiographic signs of post-traumatic arthritis were more pronounced in displaced fractures.

Aged↗
PubMed1989

The Ilizarov technique in the treatment of infected tibial nonunions.

Five patients with infected tibial nonunions and segmental defects were treated with the method of Ilizarov: application of circular small-wire fixator, corticotomy and bone transport to fill the segmental defect. Four of the five patients developed regenerate bone at the corticotomy distraction site. The one failure was related to a previous surgery--reamed locked nailing of the tibia. Three of the four patients with regenerate bone required open reduction and internal fixation at the nonunion site following bone transport. Superficial pin tract infections, broken wires and psychological intolerance of the frame were frequent but minor problems.

Bone Transplantation↗