Changes in Primary Somatosensory Cortex Following Allogeneic Hand Transplantation or Autogenic Hand Replantation.

Former amputees who undergo allogeneic hand transplantation or autogenic hand replantation (jointly, "hand restoration") present a unique opportunity to measure the range of post-deafferentation plastic changes in the nervous system, especially primary somatosensory cortex (S1). However, few such patients exist, and previous studies compared single cases to small groups of typical adults. Here, we studied 5 individuals (n = 8 sessions: a transplant with 2 sessions, a transplant with 3 sessions, and three replants with 1 session each). We used functional magnetic resonance imaging (fMRI) to measure S1 responsiveness to controlled pneumatic tactile stimulation delivered to each patient's left and right fingertips and lower face. These data were compared with responses acquired from typical adults (n = 29) and current unilateral amputees (n = 19). During stimulation of the affected hand, patients' affected S1 (contralateral to affected hand) responded to stimulation in a manner similar both to amputees and to typical adults. The presence of contralateral responses indicated grossly typical S1 function, but responses were universally at the low end of the range of typical variability. Patients' affected S1 showed substantial individual variability in responses to stimulation of the intact hand: while all patients fell within the range of typical adults, some patient sessions (4/8) had substantial ipsilateral responses similar to those exhibited by current amputees. Unlike hand restoration patients, current amputees exhibited substantial S1 reorganization compared to typical adults, including bilateral S1 responses to stimulation of the intact hand. In all three participant groups, we assessed tactile localization by measuring individuals' ability to identify the location of touch on the palm and fingers. Curiously, while transplant patients improved their tactile sensory localization over time, this was uncorrelated with changes in S1 responses to tactile stimuli. Overall, our results provide the first description of cortical responses to well-controlled tactile stimulation after hand restoration. Our case studies indicate that hand restoration patients show S1 function within the range of both typical adults and amputees, but with low-amplitude and individual-specific responses that indicate a wide range of potential cortical neurological changes following de-afferentation and re-afferentation.

Maturation and experience in action representation: Bilateral deficits in unilateral congenital amelia.

Congenital unilateral absence of the hand (amelia) completely deprives individuals of sensorimotor experiences with their absent effector. The consequences of such deprivation on motor planning abilities are poorly understood. Fourteen patients and matched controls performed two grip selection tasks: 1) overt grip selection (OGS), in which they used their intact hand to grasp a three-dimensional object that appeared in different orientations using the most natural (under-or over-hand) precision grip, and 2) prospective grip selection (PGS), in which they selected the most natural grip for either the intact or absent hand without moving. For the intact hand, we evaluated planning accuracy by comparing concordance between grip preferences expressed in PGS vs. OGS. For the absent hand, we compared PGS responses with OGS responses for the intact hand that had been phase shifted by 180°, thereby accounting for mirror symmetrical biomechanical constraints of the two limbs. Like controls, amelic individuals displayed a consistent preference for less awkward grips in both OGS and PGS. Unexpectedly, however, they were slower and less accurate for PGS based on either the intact or the absent hand. We conclude that direct sensorimotor experience with both hands may be important for the typical development or refinement of effector-specific internal representations of either limb.

Tri-trophic effects of transgenic insect-resistant tobacco expressing a protease inhibitor or a biotin-binding protein on adults of the predatory carabid beetle Ctenognathus novaezelandiae.

Tri-trophic impacts on adult predatory carabid beetles, Ctenognathus novaezelandiae, of insect-resistant transgenic tobacco plants expressing a serine protease inhibitor, bovine spleen trypsin inhibitor (BSTI), or a biotin-binding protein, avidin, were investigated. Both proteins could potentially affect this beetle, since avidin is known to be insecticidal to many beetle species and C. novaezelandiae midguts were shown to contain high levels of trypsin, a protease powerfully inhibited by bovine pancreatic trypsin inhibitor (a BSTI homologue) in vitro. Newly emerged field-collected adult C. novaezelandiae were fed exclusively for 280 days on Spodoptera litura larvae raised either on non-transgenic control, transgenic avidin (55 ppm) or transgenic BSTI (68 ppm) tobacco. Despite this long-term exclusive diet, there was no treatment effect on survival or fecundity and only minor and transient effects on beetles were observed. Data pooled across time and genders showed control-prey-fed beetles weighed 3% more than BSTI-prey-fed beetles and avidin-prey-fed beetles consumed 3-4% fewer prey than control- or BSTI-prey-fed individuals. Females in all treatments gained more mass and survived longer than males. Low exposure to the proteins because of dilution and deactivation within the prey is the most likely explanation for the lack of tri-trophic effects observed. Aditionally, the presence of a digestive chymotrypsin only partially inhibited by BSTI may provide an alternative path for proteolysis.

Ultrastructural changes to the midgut of the black field cricket (Teleogryllus commodus) following ingestion of potato protease inhibitor II.

Ultrastructural changes to the midgut epithelium of nymphs of the black field cricket (Teleogryllus commodus) after ingestion of potato protease inhibitor II (PPI-II) (0.6% (w/v) in artificial diet) were determined by light and electron microscopy. Crickets fed diet containing PPI-II grew more slowly than those fed control diet and changes observed to the PPI-II-fed nymphs included reduction of midgut wall depth, vacuolisation of the epithelial cells, swelling of the microvilli, cellular protrusions into the midgut and eventual rupture of individual or small groups of epithelial cells. These changes were first seen 2 days after PPI-II ingestion. Complete disintegration of the midgut to the basement membrane was not seen during the 27-day observation period and repair and regeneration of pockets of epithelial cells was observed. Immunocytochemistry revealed that PPI-II was localised within the ectoperitrophic matrix space of the gut. The location of the peritrophic matrix was determined by labelling with wheat germ agglutinin (WGA), but no rupture of this structure was observed in PPI-II-fed nymphs.

Cytomegalovirus myocarditis in a heart transplant recipient: sensitive monitoring of viral DNA by the polymerase chain reaction.

A 54-year-old female heart transplant recipient had an acute episode of graft rejection that was treated with high-dose immunosuppression therapy. During this therapy a second febrile illness developed, which was accompanied by hypotension, anemia, and rash. Findings for subsequent myocardial biopsy specimens were negative for cytomegalovirus by culture but were strongly positive for cytomegalovirus deoxyribonucleic acid by the polymerase chain reaction. Histologic observation of viral inclusions in the myocardial fibers supported the diagnosis of cytomegalovirus myocarditis. The polymerase chain reaction therefore can provide a rapid and highly sensitive method for heart transplant patients with suspected cytomegalovirus myocarditis.

Problems with the use of the toe-spreading reflex in rats as an assay in nerve regeneration studies.

Stages in the return of the toe-spreading reflex after sciatic nerve injury were examined using the rat. It was found that the earliest stages in the return of the reflex do not indicate nerve regeneration, but rather reflect the development of adrenalin sensitivity in denervated muscles. Probably systemic adrenalin released during the reflex-testing procedure causes muscle contractions which imitate a nerve-induced toe-spread reflex.

Isolation of cDNA clones for the catalytic gamma subunit of mouse muscle phosphorylase kinase: expression of mRNA in normal and mutant Phk mice.

We have isolated and characterized cDNA clones for the gamma subunit of mouse muscle phosphorylase kinase (gamma-Phk). These clones were isolated from a lambda gt11 mouse muscle cDNA library via screening with a synthetic oligonucleotide probe corresponding to a portion of the rabbit gamma-Phk amino acid sequence. The gamma-Phk cDNA clones code for a 387-amino acid protein that shares 93% amino acid sequence identity with the corresponding rabbit amino acid sequence. RNA gel blot analysis reveals that the muscle gamma-Phk probe hybridizes to two mRNA species (2.4 and 1.6 kilobases) in skeletal muscle, cardiac muscle, and brain, but does not hybridize to liver RNA. Phk-deficient I-strain (Phk) mouse muscle contains reduced levels of gamma-Phk mRNA as compared with control mice. Although the Phk defect is an X-linked recessive trait, hybridization to a human-rodent somatic cell hybrid mapping panel shows that the gamma-Phk gene is not located on the X chromosome. Rather, the gamma-Phk cross-hybridizing human restriction fragments map to human chromosomes 7 (multiple) and 11 (single). Reduced gamma-Phk mRNA in I-strain mice, therefore, appears to be a consequence of the Phk-mutant trait and does not stem from a mutant gamma-subunit gene.