Novel genetic screen for genes involved in posterior body patterning in Drosophila

Much of our current understanding of how cytoplasmic determinants are localized and activated stems from genetic analyses in Drosophila. Characterization of mutants defective in establishing the initial embryonic body pattern has revealed the importance of mRNA localization and translational control and identified several factors required for these processes. Nevertheless, many additional genes are likely to be involved. Here, we describe a novel genetic screen designed to identify genes that participate in posterior body patterning, an elaborate process involving the sequential use of two localized cytoplasmic determinants, the products of the oskar and nanos genes. From the screen, we recovered new alleles of genes known to be required for posterior body patterning, demonstrating the validity of the approach. In addition, we isolated numerous other mutants. Further characterization of one mutant, P58, revealed that it is a novel allele of bullwinkle. We find that in bullwinkle mutants, oskar mRNA localization is not maintained in the embryo and oskar protein accumulates ectopically and to abnormally high levels. These defects are distinct from previously described perturbations in oskar activity and provide new insights into the regulation of oskar.

Amputations and replantations

Essential aspects of emergency department assessment and initial treatment of patients with traumatic amputations are outlined. Pitfalls of early treatment and indications for replantation are discussed. The dogmatic approach is avoided.

Synovialectomy and reconstruction of the retinaculum flexorum in median nerve decompression: technique and early results

450 wrists in 362 patients underwent release of carpal tunnel compression combined with synovialectomy and reconstruction of the retinaculum flexorum between 1981 and 1989. To reconstruct the retinaculum flexorum, a "flap" of the antebrachial fascia continuous with the retinaculum flexorum, based radially and distally, was elevated and sutured to the hook of the hamate. This technique provides for carpal tunnel decompression while preserving the biomechanical role of the retinaculum flexorum and the normal anatomic relationship between the flexor tendons and the axial skeleton. The patients in this study appeared to recover function faster and more completely than those undergoing division of the retinaculum flexorum alone. No secondary procedures for recurrent carpal tunnel compression were necessary.

Comparison of blood flow after warm and cool ischemia in island flaps: latissimus dorsi myocutaneous and epigastric flaps in the dog

Cooling has been reported to improve the survival of tissues used in free transfers. Very little has been written about blood flow in flaps following ischemia and about the effect of temperature on flow. In each of 4 dogs, 2 island latissimus dorsi myocutaneous flaps and 2 island epigastric axial flaps were made ischemic for one hour. Flaps were subjected to three temperature conditions during ischemia: warm ischemia, cool ischemia, and cool ischemia followed by rewarming prior to reestablishment of blood flow. Following ischemia, blood flow in the artery of the pedicle was measured using an electromagnetic flowmeter. Both latissimus dorsi and epigastric flaps subjected to warm ischemia experienced a reactive hyperemia, a period lasting several minutes during which blood flow increased severalfold over baseline flow. Cooling the latissimus dorsi flap had no major effect on this hyperemia. However, cooling the epigastric flap attenuated the hyperemic response observed in a warm flap. Both the peak flow attained and the rate of rise to peak flow were decreased. Rewarming the epigastric flap prior to clamp removal gave a hyperemia similar to that observed in the warm flap.

Blood flow after warm ischemia in island flaps: latissimus dorsi myocutaneous and epigastric flaps in the dog

Island latissimus dorsi myocutaneous flaps are compared with island epigastric flaps in the dog in terms of their ability to reestablish blood flow and maintain tissue viability after increasing periods of warm ischemia. Blood flow in the vascular pedicles of the flaps was measured after one minute to ten hours of ischemia with an electromagnetic flowmeter. The histological condition of the cutaneous and muscular portions of these flaps was examined with light microscopy at the end of the ischemia period and after reflow. In comparison to the epigastric flap, the latissimus dorsi myocutaneous flap had a greater baseline flow before ischemia, a greater rise in flow above baseline (reactive flow) after ischemia, and an equal resistance to ischemia in terms of preservation of reactive hyperemia, recovery of nutritive flow to the skin, degree of histological changes in the skin, and patency of the vascular pedicle. Despite the vulnerability of the muscular component of the latissimus dorsi myocutaneous flap to ischemia, the muscle perforators remain patent and the dermis survived even after eight hours of warm ischemia.

Infection following pulp pull-through technique of flexor tendon grafting

A sinus tract was formed and an abscess occurred in the pulp space after a flexor tendon graft was anchored to the distal end of the nail. Treatment included drainage of the abscess and excision of the sinus tract.

Three complications of untreated partial laceration of flexor tendon--entrapment, rupture, and triggering

Three patients developed complications as a result of unrepaired and untreated partial laceration of flexor tendons. In one, narrowly based flaps of the tendons became entrapped in a rent in the flexor tendon sheath. In a second, delayed rupture of the flexor pollicis longus occurred when force was applied to the tendon 2 weeks after the injury. In the third, triggering of the thumb occurred 2 months after a laceration which passed through the annular pulley into the tendon.

Methods and results of reconstruction with free flaps following resection of squamous cell carcinoma of the head and neck

Our experience with 9 patients who have undergone reconstruction with free flap transfers following resection of squamous cell carcinoma in the head and neck area is presented. The dorsalis pedis flap was used in 3 patients, the iliofemoral (groin) flap in 4, and the latissimus dorsi myocutaneous flap in 2. Four patients had received preoperative irradiation. Despite minor partial flap necrosis in 3 patients and the development of oral cutaneous fistulas in 2, all the flaps were successful in providing the necessary coverage. Reoperation in 1 patient was necessary because of thrombosis of the venous anastomosis.

Important considerations in the design and construction of groin flaps

A method for constructing groin flaps is presented which the author has used successfully. The flap is elevated medial to the sartorius muscle. The lateral femoral cutaneous nerve is preserved. The muscular branch is carefully divided to avoid damage to the superficial circumflex iliac artery. Near the femoral artery, the important draining vein, which often diverges from the cutaneous artery, must be preserved. One side of the flap is cut longer than the other and diagonal closure of the donor site and the flap are performed. This diagonal closure increases the circumference of the tube at the base of the flap, thereby reducing the risk of vascular compression. Diagonal closure also produces a spiral in the tube. The direction of the spiral can be controlled to facilitate closure of defects on the palm or dorsum of the hand.

The abdominohypogastric flap--an axial pattern flap for forearm coverage

The abdominohypogastric flap, an axial pattern flap supplied by the anterior perforating branches of the deep inferior epigastric artery and the branches of the superficial inferior epigastric artery, has been used successfully to resurface defects on the forearm in two patients. The Doppler is employed to determine the presence and the course of the superficial inferior epigastric artery in order to include branches of this artery within the base of the flap.

Methods and results of replantation following traumatic amputation of the thumb in sixty-four patients

Immediate survival and functional results were studied in 64 thumb replantations performed during a 3 year period. The failure rate, 27% overall, was higher in patients over 50 years of age (50%) and following avulsions with or without crushing injuries (58%). Long vein grafts from the radial artery proximally to the thumb arteries distally were employed in 15 patients to bypass the traumatized area in the first web space. A higher survival rate (90%) was associated with the use of vein grafts to restore venous return. Half of the patients followed 6 months or longer had good discriminatory sensibility (less than 10 mm). Sensory return and cold intolerance were worse in older patients and were not related to level of injury, mechanism of amputation, total ischemia time, or number of arteries or veins repaired. Loss of motion of the replanted thumb was a frequent cause for inadequate return of function. All thumbs should be considered for replantation, but the results will be poorer in older patients. If possible, motion of the interphalangeal and metacarpophalangeal joints should be preserved.

Classification of oblique facial clefts with microphthalmia

We believe the Tessier classification system facilitates the description of complicated facial clefts, and we describe its use in 4 cases--all of whom had variations of a Tessier-3 cleft. Microphthalmia is associated with the Tessier-3 cleft. Computerized axial tomography may be helpful in differentiating an extreme microphthalmia from a true anophthalmia, and in detecting bony clefts not seen on roentgenographic studies. Facial tomograms show that abnormalities of the medial wall of the orbit in the Tessier-3 cleft vary from actual clefts to widening of the ethmoid. In our experience (with 4 patients) mental retardation does not necessarily occur in patients with the Tessier-3 cleft and extreme microphthalmia. Abnormalities of the nasolacrimal apparatus may be the most constant finding in patients with the Tessier-3 cleft. Children with the Tessier-3 cleft should be identified early for purposes of determining the proper treatment and valid genetic counseling.

Loss of silicone implants after subcutaneous mastectomy and reconstruction

We studied 89 patients who had immediate or delayed placement of implants after subcutaneous mastectomies. The complications of infection, necrosis of the skin or areola, and extrusion of the prosthesis occurred in 28 percent of these patients, and the incidence was the same after immediate or delayed placement. Only one of the 45 patients who received prophylactic antibodies preoperatively developed an infection after insertion of the prosthesis. The late complications in some of these patients indicate the need for long-term follow-up.