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Biomedical subjects

R J Mann

Publications and source records attributed to R J Mann.

At least 19 recordsLinked to original sources
PubMed1991

Metal ion-dependent binding of gastrin to albumin.

Binding of 125I-[Nle15]gastrin to albumin purified from porcine serum, from porcine gastric mucosal cytosol, and from bovine serum has been demonstrated by covalent cross-linking and ultracentrifugation. Binding was enhanced in the presence of Zn2+, Ni2+, Cu2+, Co2+, and Cd2+, but not Ca2+, Mg2+, or Mn2+. The best fit to the binding data for bovine serum albumin was obtained with a model assuming two nonequivalent binding sites. The affinity of both sites for gastrin was increased in the presence of 100 microM Zn2+ or Ni2+ ions. The highest association constant observed was 2.3 X 10(5) M-1 in the presence of 100 microM Zn2+ ions. The similarity of the Zn(2+)-dependence of binding for bovine and porcine serum albumins, despite the replacement of His3 by Tyr, suggested that the N-terminal metal ion-binding site was not involved. Although all gastrin affinities were reduced by 50% in the presence of 150 mM NaCl, the Zn(2+)-dependence of binding was retained. We therefore propose that the ternary complex of gastrin, Zn2+ ions, and albumin may play a physiological role in the serum transport of Zn2+ ions and in the uptake of Zn2+ ions from the lumen of the gastrointestinal tract.

Animals↗
PubMed1990

Controlled tissue expansion of a groin flap for upper extremity reconstruction.

A large upper extremity defect in an 8-year-old girl was resurfaced with an expanded groin flap. Tissue expansion allowed complete coverage of the defect while minimizing the donor deformity. Pretransfer expansion of pedicled flaps offers an alternative to free-flap reconstruction of complex upper extremity defects. This is especially valuable in the pediatric patient, in whom donor-site morbidity can be significant.

Child↗
PubMed1989

Wrist pain: correlation of clinical and plain film findings with arthrographic results.

A technique adding digital subtraction to otherwise standard wrist arthrography allows more precise determination of the site of radiocarpal-midcarpal communications. Since arthrographic results often do not correlate with clinical findings, we became interested in correlating these various modalities. The precision of our arthrographic interpretation makes these correlations meaningful. In 72 consecutive patients who had digital subtraction wrist arthrograms, both clinical sites of pain and plain film abnormalities were correlated with arthrographic findings. The results indicate that those patients with ulnar-sided pain more commonly have perforations in that region (88%). Radial-sided pain is a poor indicator of a radial site of perforation. Scapholunate dissociation does not correlate highly with scapholunate perforation (26%).

Adolescent↗
PubMed1989

Submuscular transposition of the ulnar nerve.

A retrospective study of 26 submuscular ulnar nerve transpositions was performed with the specific use of grip and pinch analysis to evaluate this form of objective testing. Twenty-six patients were treated by submuscular transposition of the ulnar nerve between 1981 and 1985 and were followed an average of 21 months. Preoperative and postoperative analysis consisted of subjective questioning, clinical examination, quantitative two-point discrimination, quantitative pinch and grip analysis, and electromyographic (EMG) and nerve conduction velocity (NCV) evaluation. Many of the patients suffered from associated problems such as alcohol abuse, diabetes mellitus, and concurrent Guyon's canal compression, which adversely affected the outcome. Subjectively, 62% were improved, 31% were no better, and 7% were worse. Clinical examination demonstrated 46% improved, 35% no better, and 19% worse. Quantitative two-point discrimination was better in 59%, unchanged in 26%, and worse in 15%. Quantitative pinch and grip analysis revealed 28% improved, 56% with little improvement, or the same, and 16% worse, while EMG/NCV showed one-third of the patients in each category postoperatively. Quantitative pinch and grip analysis provided good preoperative and postoperative documentation, which is absent from previous studies in the literature concerning ulnar nerve transportation.

Adult↗
PubMed1988

Simultaneous fractures of the distal radius and scaphoid.

Simultaneous fractures of the distal radius and scaphoid are uncommon injuries for which the treatment is controversial. Nine patients with these fractures are presented. Five patients were available for long-term followup. In the series, there were five Colles and four Smith's fractures of the distal radius. All scaphoid fractures occurred at the anatomic waist. All injuries resulted from falls of considerable force producing hyperextension at the wrist. The ages of the patients ranged from 21 to 90 years (median, 34). All fractures were placed in a thumb spica cast with the wrist in neutral position. Five fractures required a second reduction of the radius and were placed in external skeletal fixation. No scaphoid fracture was displaced by this treatment, and all scaphoid fractures progressed to union. The principal deformity at followup was an average 16 degrees loss of volar tilt. Residual pain or functional disability was not noted. We conclude that these fractures can be successfully treated by reduction of the radius and immobilization by whatever means necessary to maintain an acceptable position. Scaphoid reduction and healing seemed unaffected by the method of treatment used to treat the distal radius fracture in this series.

Adult↗
PubMed1987

Extracutaneous sporotrichosis.

Although an uncommon cause of arthritis, sporotrichosis may mimic other forms of joint disease and should be considered in the differential diagnosis of a patient with a chronic monoarticular arthritis or if granulomatous synovitis is recognized by histologic examination. Characteristic skin findings may be absent, repeated cultures may be necessary, severe osseous destructive changes can occur, and surgical extirpation of the diseased tissue combined with amphotericin B chemotherapy is recommended.

Arthritis, Infectious↗
PubMed1986

The stability of internal fixation in the proximal phalanx.

A biomechanical study was performed to assess quantitative differences in the stability obtained with five commonly used types of internal fixation used in proximal phalangeal fractures. The techniques included dorsal plating, dorsal plating combined with an interfragmentary lag screw, two interfragmentary lag screws, tension-band technique, and crossed Kirschner wires. Rigidity and strength in apex palmar bending were determined after oblique osteotomy and fixation of the proximal phalanx. The failure modes for each fixation technique were also observed and described. The results showed that both of the techniques that used interfragmentary lag screws across the oblique osteotomies provided significantly more rigidity than did dorsal plating alone or the wired configurations but that measurements of strength were similar between all techniques tested. Dorsal plates were at a mechanical disadvantage on the compression surface in our apex palmar bend test and consequently provided no more rigidity and strength than did the wired techniques. The tension band technique represented a combination of stiff and flexible intraosseous wires without strict application of tension band principles and provided intermediate rigidity and strength. Rigidity and strength in intact proximal phalanges in the controls were significantly greater than in all techniques tested.

Biomechanical Phenomena↗
PubMed1985

Comparison of internal fixation techniques in metacarpal fractures.

A biomechanical study assessed quantitative differences in the stability that was obtained by five commonly used types of internal fixation employed in metacarpal fractures. The techniques included dorsal plating, dorsal plating combined with an interfragmentary lag screw, crossed Kirschner wires, a single intraosseous wire combined with a single oblique Kirschner wire, and a single intraosseous wire alone. Rigidity and strength in torsion and bending were determined after transverse osteotomy and fixation of the metacarpal were performed. The failure modes for each fixation technique were also observed and described. Significant differences in rigidity were found between the plated configurations (with or without an interfragmentary lag screw) and the wired configurations in both apex dorsal bending and axial torsion. The three wired configurations were not significantly different from each other except in torsion. Analysis of the bending moments that were required to produce both yield and failure in apex dorsal bending and also the energy absorbed to yield showed similar disparity between plated and wired techniques. For metacarpal fixation, dorsal plating with or without lag screws provides significantly more stability than do wired techniques and approaches that provided by intact bones.

Biomechanical Phenomena↗
PubMed1985

Chondroblastoma of a metacarpal. Report of a case and review of the literature.

A 25-year-old white man had a tender mass on the dorsum of his hand. Routine examination and radiographs revealed a benign lytic neoplasm in the base of the ring metacarpal. The primary treatment consisted of curettage and cancellous bone grafting. The biopsy diagnosis was chondroblastoma. The patient is asymptomatic and has a normal radiograph after a follow-up period of one year. This unusual tumor has seldom been reported at sites distal to the wrist. The report of this chondroblastoma serves as a reminder that not all benign lytic processes in the hand are enchondromas.

Adult↗