Replication of feline herpesvirus and feline calicivirus in cell and organ cultures.

Virus titers from feline herpesvirus-infected feline tracheal organ cultures were higher than those from feline kidney cell cultures. The time for the development of peak viral yields was longer in organ culture as compared to cell cultures. Feline tracheal organ cultures infected with feline calicivirus produced minimal viral titers.

Thiopurine S-methyltransferase pharmacogenetics: genotype to phenotype correlation in the Slovenian population.

The toxicity of thiopurine drugs has been correlated to the activity of thiopurine S-methyltransferase (TPMT), whose interindividual variation is a consequence of genetic polymorphisms. We have herein investigated the relevance of some genetic markers for the prediction of thiopurine-related toxicities and to determine the genotype to phenotype correlation in the Slovenian population. The most prevalent mutant allele in the Slovenian population is TPMT*3A (4.1%), followed by TPMT*3C (0.5) and TPMT*3B (0.3), while the TPMT*2 allele was not found in any of the examined samples. TPMT enzyme activity distribution in the subgroup sample was bimodal and as such correlated with genetic data. Using a cutoff value of 9.82 pmol/10(7) RBC per h, the genetic data correctly predicted TPMT enzyme activity in 91.6% of the examined individuals. Pharmacogenetic TPMT analyses have therefore proved to have significant clinical implications for prediction of individuals' responses to treatment with thiopurine drugs in order to avoid possible life-threatening therapy-related toxicities.

Flexor tendon ruptures secondary to hamate hook fractures.

Four patients with flexor tendon ruptures secondary to hook of the hamate fracture are described. None of the patients had the diagnosis of fracture made before tendon rupture. All patients were treated with excision of the fractured hook and tendon repair. The tendon repair was usually an end-to-side (Y junction) of the profundus of the small to the profundus of the ring finger. After operation, all patients were free of pain and returned to their preinjury activity levels, but most had some limitation of motion in the digit with the tendon repair. The complication of tendon rupture not uncommonly follows basilar hook of the hamate fractures. Treatment by excision of the fracture and end-to-side tendon repair produces satisfactory results. Range of motion after tendon repair seems to depend more on the patient's age and the amount of inflammation at the site of repair rather than on the method of tendon repair.

Compression of the deep branch of the ulnar nerve at the adductor hiatus producing pain without muscle atrophy.

Compression of the deep branch of the ulnar nerve distal to the pisohamate hiatus is rare. Two cases of compression of the deep branch at the adductor hiatus are presented. These cases are unique because of pain in the hand without muscle atrophy. One patient has had surgical treatment, and the other patient's symptoms are not severe enough to warrant surgical treatment.

Ulnar shortening for tears of the triangular fibrocartilaginous complex.

Ten consecutive patients had their ulnas shortened for treatment of ulnar wrist pain associated with triangular fibrocartilaginous complex tears. Each injury was traced to a previous fall or an overuse syndrome. Conservative treatment failed. In all patients, x-ray films showed ulnar positive or neutral variance. The ulna was shortened an average of 2 mm. Frank ulnolunate abutment and/or cartilage degeneration was found in six cases. Follow-up averaged 23 months, and except for one patient in whom radiocarpal arthritis developed, the remaining patients were satisfied and returned to their work or previous level of activity. Relief of pain, grip strength, and range of motion were excellent, except for an average decrease in flexion of 25.8 degrees (p = 0.01). Hardware irritation was noted in six patients. These findings substantiate the use of ulnar shortening to relieve ulnolunate impingement in patients with ulnar positive or neutral wrists in whom ulnar wrist pain develops and who demonstrate triangular fibrocartilaginous complex tears after acute trauma and/or overuse syndromes.

Hook of the hamate fractures. Diagnosis, treatment, and complications.

Four cases of undiagnosed hook of the hamate fracture are presented. In each case, the initial injury was considered trivial; medical attention was not sought until rupture of the little profundus/superficialis tendon occurred. All were treated with excision of the hook and tendon repair, which usually consisted of an end-to-side or "Y" type repair of the little to the ring profundus. Postoperatively, all patients were pain-free; they returned to their respective preinjury activities, although most had some limitation of motion in the digits with the tendon repair. A review of the English literature revealed 127 cases of hook of the hamate fracture, with 14 instances of associated tendon rupture and four histories of tendon fraying. The addition of these four cases constitutes a rupture/injury rate of approximately 14%. Since tendon rupture is a serious problem that not uncommonly follows hook of the hamate fracture, a high index of suspicion must be maintained when initially evaluating these injuries.

Tuberculous tenosynovitis of the wrist. Two case reports.

Tuberculosis was first described in 1756 by Acrel in a case report. Subsequent reports of musculoskeletal tuberculosis documented the uncommon occurrence of hand and wrist involvement. The two cases presented here demonstrate the difficulty in eradicating the organism even with modern regimens of chemotherapy. Intraoperative Gram's stain and frozen sections were useful to rule out other etiologies. Firm diagnosis must be established by tissue culture. The first case appeared cured after thorough initial debridement and had no recurrence for 36 years. While recurrences are common in patients treated with debridement alone, most appear within one year after the index procedure. The amount of time that elapsed in this case is unusual and serves as a sobering reminder that tuberculosis may recur at a time distant from the initial procedure. The second patient had tuberculosis diagnosed elsewhere and was treated twice with antituberculous chemotherapy. Although the first course of therapy for six months may have been inadequate, the second course with multiple drugs for 18 months would certainly be considered adequate; yet he had a recurrence in his wrist eight months after completing treatment. These two cases illustrate the fastidious nature of the Mycobacterium tuberculosis organism and the need for a combined treatment protocol of meticulous surgical debridement and combined chemotherapy.

Volar plate fractures.

Rupture of the volar plate of the proximal interphalangeal joint, usually secondary to hyper-extension injury, may be accompanied by a radiographically evident avulsion fracture at the base of the middle phalanx. Findings were reviewed in 55 patients with 58 cases of volar plate fracture. This fracture should be specifically looked for in a patient with the typical history, since it may be the only radiographic evidence of a potentially disabling injury.

Results of nerve grafting in severe soft tissue injuries.

Nerve grafting was performed in a series of patients, 81% of whom had associated severe soft tissue injuries in the area in which nerve grafting was done. Other factors that have been shown to have an adverse effect on nerve grafting results were analyzed and were not thought to be major factors influencing results. Results were worse than those of previous reports in which the initial injury was less severe. The initial soft tissue injury is very important in predicting how well a nerve graft will function. Nerve grafting is a valuable procedure even in the face of severe soft tissue injuries, since it alone can restore protective sensation.

Intraoperative assessment of median nerve blood flow during carpal tunnel release with laser Doppler flowmetry.

Eleven consecutive median nerves in patients with clinical carpal tunnel syndrome were examined prospectively with laser Doppler flowmetry. All procedures were done without a tourniquet with the patient under local or general anesthesia. Multiple measurements of median nerve blood flow were obtained during carpal tunnel release. Flow characteristics proximal to the transverse carpal ligament did not change after release of the ligament. Beneath the transverse carpal ligament, initial flow was random in 10 of 11 nerves. Within 1 minute after release of the transverse carpal ligament, flow became pulsatile and synchronized with the patient's pulse in nine nerves. Although preliminary, these data suggest that in carpal tunnel syndrome the segment of median nerve beneath the carpal ligament is relatively ischemic and this ischemia may be a factor in the development of symptomatic median nerve entrapment. The rapid return of a pulsatile signal within the nerve after release is positively correlated with relief or improvement of median nerve dysesthesias.

Distal interphalangeal joint arthrodesis comparing tension-band wire and Herbert screw: a biomechanical and dimensional analysis.

Thirty cadaveric distal interphalangeal joints (15 male and 15 female joints) were prepared with either a Herbert screw or a tension-band wire technique to simulate an arthrodesis. To elucidate mechanical differences between these constructs, the strength of the specimens was determined for three-point anteroposterior and lateral bending and for axial torsion. The Herbert screw demonstrated significantly greater anteroposterior bending strength and greater torsional rigidity when compared to the tension-band wire technique. For dimensional analysis, the height and width of each distal phalanx was measured prior to fixation, 4 mm from the distal tip of the bone (the region that must accommodate the large-diameter threads of the Herbert screw). Results indicated that the mean height of the distal phalanx (3.55 mm) is smaller than the diameter of the screw (3.90 mm). Fracture or thread penetration at the tip of the distal phalanx during screw placement occurred in 25 of the specimens overall and in all the female phalanges, often resulting in stretching or violation of the nail bed. Despite fracture or screw penetration, the Herbert screw appears to offer additional strength that may be clinically important for joint arthrodesis.