Search PubMed⌕ Search

Biomedical subjects

D Mass

Publications and source records attributed to D Mass.

18 recordsLinked to original sources
PubMed2001

Bone suture anchors versus the pullout button for repair of distal profundus tendon injuries: a comparison of strength in human cadaveric hands.

Avulsion or distal tendon laceration of flexor digitorum profundus (FDP) is classically repaired to the base of the distal phalanx via a pullout suture over a button. Bone suture anchors, used extensively in other surgical areas, have recently been proposed for reattachment of the FDP to the distal phalanx. The FDP tendons of the index, long, and ring fingers in 9 fresh frozen cadeveric hands were randomized to 1 of 3 repair techniques after simulated distal avulsion injuries. These were the pullout button using 3-0 monofilament nylon in a 2-strand Bunnell suture pattern, the 1.8 mm Mini QuickAnchor (Mitek Products, Norwood, MA) using 3-0 braided polyester in a 2-strand Bunnell suture pattern, and the Mitek micro anchor using 3-0 braided polyester with a modified 4-strand Becker suture pattern. Nine specimens were loaded to failure, noting maximum load and mode of failure. The 1.3 mm Micro QuickAnchor (Mitek) technique (69.6 +/- 10.8 N) was significantly stronger than the pullout button (43.3 +/- 4.8 N) or the Mini anchor technique (44.6 +/- 12.7 N). The Micro bone suture anchor provides a stronger tendon to bone repair than the pullout button or the Mini anchor. Given the disadvantages of the pullout button, the Micro bone suture anchor with the modified Becker technique is worth consideration as an alternative method to repair distal FDP avulsions.

Aged↗
PubMed1996

Mechanical analysis of the palmar aponeurosis pulley in human cadavers.

The anatomy of the palmar aponeurosis pulley has been well described, but its biomechanical function is not as well characterized. This study describes the functional importance of the palmar aponeurosis pulley by using efficiency parameters. We obtained data by generating load, excursion, and work efficiencies in the intact pulley system and compared these to the efficiencies obtained after sectioning the palmar aponeurosis pulley alone and in combination with the proximal annular pulleys. The variability associated with comparisons between different fingers and hands was therefore diminished. Sectioning the palmar aponeurosis pulley alone did not significantly change any of the efficiency parameters. When the palmar aponeurosis pulley was sectioned in combination with either or both of the proximal annular pulleys (A1, A2) there was a significant decrease in excursion efficiency. Only after all three proximal pulleys were sectioned did the load efficiency increase and the work efficiency decrease significantly. These findings prove that the palmar aponeurosis pulley in combination with the proximal annular pulleys acts to decrease the tendency to bowstringing around the metacarpophalangeal joint. The increased load efficiency is probably the result of a decrease in friction and counteractive forces generated by the integrated fibers of the intact palmar aponeurosis pulley. Change in work is due not only to an increase in excursion, but also to the increased resistance that results from the acute angulation that the tendon must endure as it follows behind the remaining pulleys during flexion. Intergroup comparisons show a significant contribution by the palmar aponeurosis pulley. This study demonstrates a significant biomechanical role for the palmar aponeurosis pulleys and suggests that it be considered similar to the annular and cruciate flexor tendon pulleys in importance.

Biomechanical Phenomena↗
PubMed1996

Efficiency of the flexor tendon pulley system in human cadaver hands.

The efficiency of the flexor tendon system was examined in a human cadaver model. Pulleys were randomly sectioned, and the results were evaluated on the basis of the tendon excursion, force generated at the fingertip, and the work (force multiplied by distance) involved, as compared to the intact pulley system. When a single minor pulley (A1 or A5) was cut, there was no statistical difference in work efficiency or excursion efficiency from controls. Cutting all minor pulleys (A1, A3, A5) lead to a significant loss in excursion efficiency. The intact three pulley systems of A2, A3, and A4 were near normal and statistically better than A2 and A4 together for work efficiency. Cutting one of the major pulleys (A2, A4) resulted in significant changes in efficiency, but what was unexpected was to find an 85% loss of both work and excursion efficiency for the loss of A4 but only an excursion difference of 94% for the loss of A2. Our findings demonstrated that in this model, with the influence of the skin removed, A4 absence produced the largest biomechanically measured efficiency changes and that a combination of A2, A3, and A4 was necessary to preserve both work and excursion efficiency.

Biomechanical Phenomena↗
PubMed1994

Dynamic analysis of profundus tendon function.

A method for analysis of hand function is reported through evaluation and characterization of flexor digitorum profundus (FDP) tendon mechanics. A testing platform is used that allows for the dynamic evaluation of intact cadaver hand mechanics under normal and pathologic conditions using simultaneous measurements of tendon load, tendon excursion, grip strength, pinch strength, and joint angle. This study of FDP tendons in normal fresh cadaver hands demonstrates that FDP tendon excursion increases as the number and size of joints flexed increases. Extensor counterweighting 500 g, increases FDP tendon load and work but not excursion requirements, and FDP loads of up to 75 N are required for single finger grip strengths of 4 kg force. These loads do not result in permanent (plastic) deformation of either the tendon or the restraining soft tissues. Detailed descriptions of the platform and the mechanical tests performed are provided.

Adult↗
PubMed1993

Cohort study of rotavirus serotype patterns in symptomatic and asymptomatic infections in Mexican children.

A cohort of 200 Mexican children from a low income periurban community was monitored from birth to the age of 2 years to determine the serotype-specific incidence, morbidity and seasonal pattern of symptomatic and asymptomatic human rotavirus (HRV) infections. A total of 177 HRV infections occurred in 134 (67%) children; 50% of these infections were asymptomatic. The incidence of all HRV infections was 0.6 episode/child year and was inversely related to age (r = -0.93; P < 0.01). The incidence of HRV-associated diarrhea was 0.3 episode/child year, with the highest frequency and severity occurring in infants between 4 and 6 months of age. HRV infections were more frequent each autumn, with a changing sequential pattern of predominant serotypes. Overall serotype 3 (34%) was the most frequent, followed by serotypes 1 (16%), 2 (15%) and 4 (6%). The 4 serotypes were associated with a similar risk for diarrhea and severity of diarrhea. In 23 (26%) HRV diarrhea-associated infections, an additional enteropathogen was identified; these mixed infections were more frequent in older children (chi square, 4.45; P < 0.05) but were not more severe (chi square, 0.02; P > 0.05). Our data indicate that HRV infections were common early in life, seasonal, frequently asymptomatic and caused by a variety of serotypes, none of which was a risk factor for diarrhea or severity of diarrhea.

Cohort Studies↗
PubMed1991

Biomechanical analysis of intrinsic tendon healing in vitro and the effects of vitamins A and E.

This in vitro study was designed to test the hypothesis that flexor tendons have an intrinsic capability to heal as judged by rigorously defined biomechanical criteria. Rabbit forepaw flexor tendons (n = 114) were transected and repaired in zone II and cultured in standard media or media supplemented with vitamin A or E. Tenorrhaphies were disrupted at 0, 2, 8, and 12 weeks after repair by fixed-speed tensiometry. The following parameters were calculated: true stress, true strain, and normalized energy absorption. Statistical analysis was by Student's t test. Peak stress (strength) increased equally in all groups over time (p less than 0.05), while normalized energy absorption (toughness) was markedly higher in the vitamin E-treated group after 2 weeks' incubation (p less than 0.05). These data represent the first biomechanical evidence of intrinsic tendon healing in vitro. Biomechanical methodology and vitamin effects are discussed in detail.

Animals↗
PubMed1981

The predictive value theory redefines quality assurance.

Performing laboratory tests that are unreliable or diagnostically meaningless is costly, time-consuming, and wasteful. The Predictive Value Model provides a means to eliminate this wastefulness and increase the utility of laboratory testing. This paper describes the way in which data regarding a test's predictive value, and efficiency may be used to determine which tests are of maximum utility in specific situations.

Clinical Laboratory Techniques↗
PubMedDate not supplied

Staff retention: a major key to management's success.

The number of qualified and competent clinical laboratory sciences (CLS) professionals is rapidly declining. As competition grows and the clinical laboratory comes under greater scrutiny, the laboratories that survive will be those that recognize that their, employees are their greatest asset. However, retaining expert CLS professionals requires a dramatic change in management's belief system regarding the value of its personnel assets. Management must create a culture of empowered people who have the freedom to exhibit self-direction in achieving the organization's mission and goals. Management must consider its employees valuable enough to invest in their professional growth. A laboratory's long-term sustainability and economic performance will depend on a committed workforce that supports their organization's success.

Humans↗