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Biomedical subjects

M Merle

Publications and source records attributed to M Merle.

At least 127 records · Page 7Linked to original sources
PubMed1984

Substrate depletion analysis as an approach to the pre-steady-state anticooperative kinetics of aminoacyl adenylate formation by tryptophanyl-tRNA synthetase from beef pancreas.

The formation of tryptophanyl adenylate catalyzed by tryptophanyl-tRNA synthetase from beef pancreas has been studied by stopped-flow analysis under conditions where the concentration of one of the substrates was largely decreasing during the time course of the reaction. Under such conditions a nonlinear regression analysis of the formation of the adenylate (adenylate vs. time curve) at several initial tryptophan and enzyme concentrations gave an accurate determination of both binding constants of this substrate. The use of the jackknife procedure according to Cornish - Bowden & Wong [ Cornish - Bowden , A., & Wong , J.J. (1978) Biochem. J. 175, 969-976] gave the limit of confidence of these constants. This approach confirmed that tryptophanyl-tRNA synthetase presents a kinetic anticooperativity toward tryptophan in the activation reaction that closely parallels the anticooperativity found for tryptophan binding at equilibrium. Both sites are simultaneously forming the adenylate. The dissociation constants obtained under the present pre-steady-state conditions for tryptophan are KT1 = 1.6 +/- 0.5 microM and KT2 = 18.5 +/- 3.0 microM at pH 8.0, 25 degrees C. The rate constant kf of adenylate formation is identical for both active sites (kf = 42 +/- 5 s-1). The substrate depletion method presently used, linked to the jackknife procedure, proves to be particularly suitable for the determination of the kinetic constants and for the discrimination between different possible kinetic models of dimeric enzyme with high substrate affinity. In such a case this method is more reliable than the conventional method using substrate concentrations in high excess over that of the enzyme.

Adenosine Triphosphate↗
PubMed1984

[A case of osteopathia striata].

We report a case of osteopathia striata, which is an osseous dysplasia with linear striations of the metaphyses of long bones. Our case is very unusual as there are no associated abnormalities of the bones. Osteopathia striata should not be mistaken for osteopoikilosis. Osteopathia striata is not only a peculiar roentgenologic feature: when it is diagnosed, other abnormalities should be looked for, especially cranial osteosclerosis, which may result in complications.

Adult↗
PubMed1984

Single stage thumb reconstruction by a composite forearm island flap.

Single stage thumb reconstruction is possible with a new composite skin bone flap from the forearm. The primary vascularisation of skin and bone avoids the disadvantages of the conventional multi-staged procedures such as neurovascular insufficiency, infection and bone absorption. It does not require a surgical team with microsurgical expertise. The best indication is the reconstruction in the subtotal thumb amputation.

Adult↗
PubMed1984

Toe-to-hand transfers in reconstructive surgery of the hand. Experience with seventy-one cases.

Based on a homogeneous series of 71 toe-to-hand transfers performed between February 1975 and December 1982 the same surgeon, the authors have tried to define their present day indications. Technical modifications have been described for the second toe transfer : isolated dorsal approach of the toe with early-stage resection of the second metatarsal bone, utilisation of the plantar metatarsal artery of the second interosseous space, utilisation of the volar vessels for the anastomosis at the recipient site, dorsal subcutaneous tunnel for the venous anastomosis of the hand. Aside from the usual indications for thumb reconstruction (11 cases) and 26 cases of transfers for reconstruction in long finger injuries, the indications for partial transfers have become more and more frequent : pulpar (9 cases), pulp + bone + nail (10 cases), isolated nail (1 case), nail + bone (2 cases), first web space (1 case), double twisted toe (5 cases) and articular (6 cases) transfers.

Adult↗
PubMed1984

[Ungual synthesis].

In case of dorsal sectioning of the distal phalanx, the nail can be used to mobilize and to bring the bone fragments together. A needle is passed through the nail and the nail bed, and the two fragments can be brought together with a metallic tension suture.

Finger Injuries↗
PubMed1984

[Compression of the brachial plexus by a pseudarthrosis of the 1st rib].

The authors have described the case of a thoracic outlet syndrome with costoclavicular compression of the brachial plexus, secondary to non-union of a first rib fracture. Treatment consisted in transaxillary removal of the first rib, as described by Roos. Intrafascicular neurolysis of the posterior and medial trunks was performed at the same time, and was followed by quick clinical and electromyographical recovery.

Adult↗
PubMed1984

[Improvement of proximal interphalangeal flexion of the 5th finger in wounds or avulsions of the flexor profundus tendon].

The flexor superficialis of the little finger alone is frequently unable to provide good flexion of the PIP joint. This was verified in half of the hands tested in 45 normal volunteers. These data stress the mandatory repair of the flexor profundus tendon in emergency situations. In secondary reconstruction the authors advocate a side-to-side anastomosis between the sublimis and profundus tendons in order to reinforce the flexion of the PIP joint.

Finger Joint↗
PubMed1984

Functional comparison between pollicization and toe-to-hand transfer for thumb reconstruction.

The functional results of two methods of thumb reconstruction, pollicization, and toe transplantation were evaluated in four groups of patients: Group I, those missing the thumb but with four other normal digits; Group II, those missing the thumb with partially mutilated or amputated other digits; Group III, those with a metacarpal hand; and Group IV, those with a distal thumb amputation. In each group, results were compared in six categories: mobility, strength, sensibility, cosmetic appearance, pinch accuracy, and grasping power. In Group I, pollicization provided superior sensibility and mobility, but grasping power was best achieved by transfer of the big toe. Second toe transfer and pollicization both resulted in some weakness, compared with the normal hand. Pinch accuracy, related to the quality of sensibility, was better achieved by pollicization than by any free transfer. In Group II, although pollicization of a mutilated digit is more controversial, a very good functional level was reached in some cases, directly related to the amount of preoperative sensibility and the mobility of the proximal interphalangeal joint in the transferred digit. Reduction of strength and prehension depended on the number and quality of the remaining nontransferred digits. Toe transfer yielded better results in all six categories, as the severity of digit mutilation increased. In Group III, pollicization of the second metacarpal achieved a very rudimentary pinch, with toe transfer allowing for much greater prehension possibilities. In Group IV, distal thumb amputations were treated with distal digital pollicization as well as with partial toe transplantation. Both methods did well; however, indications for pollicization were extremely limited. Comparing results of big and second toe transfer for thumb reconstruction, big toe transfer achieved superior results, in both functional and cosmetic aspects.

Amputation, Traumatic↗
PubMed1984

The repair of peripheral nerve injuries in emergency.

Peripheral nerve injuries must be considered as serious surgical emergencies for they are often associated with vascular lesions. Primary repair of clean-cut injuries of peripheral nerves by microsurgical techniques yields better results than the best of secondary repairs.

Electromyography↗
PubMed1984

[Irreducible closed luxation of the distal interphalangeal joint. Apropos of 2 cases].

Two irreducible dislocations of the distal digital interphalangeal joint have been seen by the author. One was dorsally displaced with interposition of the extensor tendon, and the other was a palmar displacement with interposition of the flexor tendon. Both cases were successfully treated by open reduction. A review of the literature confirms the rarity of this condition.

Adult↗