Mossy and climbing fibre organization on the anterior lobe of the cerebellum activated by forelimb and hindlimb areas of the sensorimotor cortex

Summary Stimulation of forelimb and hindlimb areas of the sensorimotor cortex in the cat evokes in the lobus anterior of the cerebellum an early response at latency of 3–3.5 msec due to the mossy fibre input (MF) and a later response at latency of 13–16 msec due to the climbing fibre (CF) input.In the pars intermedia these two types of responses are organized in a somatotopic manner: the hindlimb area projects in lobuli HIV and HIII whereas the forelimb area projects to lobulus HV. In the vermis a somatotopic arrangement is less clear. Both forelimb and hindlimb areas of the sensorimotor cortex project to lobuli III, IV and V: on a maintained somatotopy in a caudo-rostral direction there is a tendency for the hindlimb area of the sensorimotor cortex to be well represented in a longitudinal strip close to the paravermal sulcus. This arrangement in the vermis is evident for the CF pathways, but more difficult to demonstrate for the MF pathways.The forelimb area of the sensorimotor cortex projects to those areas of the lobus anterior impinged upon by the forelimb nerves through both the MF and CF systems and the same holds true for the hindlimb area and the hindlimb nerves.     

GABRD encoding a protein for extra- or peri-synaptic GABAA receptors is a susceptibility locus for generalized epilepsies

A major challenge in understanding complex idiopathic generalized epilepsies has been the characterization of their underlying molecular genetic basis. Here, we report that genetic variation within the GABRD gene, which encodes the GABAA receptor delta subunit, affects GABA current amplitude consistent with a model of polygenic susceptibility to epilepsy in humans. We have found a GABRD Glu177Ala variant which is heterozygously associated with generalized epilepsy with febrile seizures plus. We also report an Arg220His allele in GABRD which is present in the general population. Compared with wild-type receptors, alpha1beta2Sdelta GABAA receptors containing delta Glu177Ala or Arg220His have decreased GABAA receptor current amplitudes. As GABAA receptors mediate neuronal inhibition, the reduced receptor current associated with both variants is likely to be associated with increased neuronal excitability. Since delta subunit-containing receptors localize to extra- or peri-synaptic membranes and are thought to be involved in tonic inhibition, our results suggest that alteration of this process may contribute to the common generalized epilepsies.     

Genotype-phenotype correlation and frequency of the 3199del6 cystic fibrosis mutation among I148T carriers: results from a collaborative study.

PURPOSE: We expect that the mutation panel currently recommended for preconception/prenatal CF carrier screening will be modified as new information is learned regarding the phenotype associated with specific mutations and allele frequencies in various populations. One such example is the I148T mutation, originally described as a severe CF mutation. After implementation of CF population-based carrier screening, we learned that I148T exists as a complex allele with 3199del6 in patients with clinical CF, whereas asymptomatic compound heterozygotes for I148T and a second severe CF mutation were negative for 3199del6. METHODS: We performed reflex testing for 3199del6 on 663 unrelated specimens, including I148T heterozygotes, compound heterozygotes, and a homozygous individual. RESULTS: Less than 1% of I148T carriers were also positive for 3199del6. Excluding subjects tested because of a suspected or known CF diagnosis or positive family history, 0.6% of I148T-positive individuals were also positive for 3199del6. We identified 1 I148T homozygote and 6 unrelated compound heterozygous individuals with I148T and a second CF variant (2 of whom also carried 3199del6). In addition, one fetus with echogenic bowel and one infertile male were heterozygous for I148T (3199del6 negative). CONCLUSIONS: Reflex testing for 3199del6 should be considered whenever I148T is identified. Reflex testing is of particular importance for any symptomatic patient or whenever one member of a couple carries a deleterious CF mutation and the other member is an I148T heterozygote. Further population data are required to determine if I148T, in the absence of 3199del6, is associated with mild or atypical CF or male infertility.     

Genome-wide examination of myoblast cell cycle withdrawal during differentiation.

Skeletal and cardiac myocytes cease division within weeks of birth. Although skeletal muscle retains limited capacity for regeneration through recruitment of satellite cells, resident populations of adult myocardial stem cells have not been identified. Because cell cycle withdrawal accompanies myocyte differentiation, we hypothesized that C2C12 cells, a mouse myoblast cell line previously used to characterize myocyte differentiation, also would provide a model for studying cell cycle withdrawal during differentiation. C2C12 cells were differentiated in culture medium containing horse serum and harvested at various time points to characterize the expression profiles of known cell cycle and myogenic regulatory factors by immunoblot analysis. BrdU incorporation decreased dramatically in confluent cultures 48 hr after addition of horse serum, as cells started to form myotubes. This finding was preceded by up-regulation of MyoD, followed by myogenin, and activation of Bcl-2. Cyclin D1 was expressed in proliferating cultures and became undetectable in cultures containing 40% fused myotubes, as levels of p21(WAF1/Cip1) increased and alpha-actin became detectable. Because C2C12 myoblasts withdraw from the cell cycle during myocyte differentiation following a course that recapitulates this process in vivo, we performed a genome-wide screen to identify other gene products involved in this process. Using microarrays containing approximately 10,000 minimally redundant mouse sequences that map to the UniGene database of the National Center for Biotechnology Information, we compared gene expression profiles between proliferating, differentiating, and differentiated C2C12 cells and verified candidate genes demonstrating differential expression by RT-PCR. Cluster analysis of differentially expressed genes revealed groups of gene products involved in cell cycle withdrawal, muscle differentiation, and apoptosis. In addition, we identified several genes, including DDAH2 and Ly-6A, whose expression specifically was up-regulated during cell cycle withdrawal coincident with early myoblast differentiation.     

Supernatants from co-cultured endothelial cells and syncytiotrophoblast microvillous membranes activate peripheral blood leukocytes in vitro

There is evidence for both endothelial cell and peripheral blood leukocyte (PBL) activation in pre-eclampsia. Syncytiotrophoblast microvillous membranes (STBM) are shed in greater quantities from the placenta in pre-eclampsia, disrupt cultured endothelial cells in vitro and may be the immediate cause of the maternal syndrome. The aim of this study was to determine if endothelial cells co-cultured with STBM release factors that can activate PBL in vitro. Flow cytometry was used to measure changes in intracellular free ionized calcium ([Ca2+]i), pH (pHi) and reactive oxygen species (iROS) as indices of leukocyte activation. PBL from male non-pregnant donors was exposed to supernatants from human umbilical vein endothelial cells (HUVEC) cultured with STBM. The time course of changes in [Ca2+]i, pHi and iROS was determined and compared with appropriate control measurements. The test supernatants caused significant activation of granulocytes and monocytes in terms of increases in [Ca2+]i and falls in pHi and release of iROS. Lymphocytes responded only with respect to increases in iROS. The results define a possible mechanism for the activation of PBL in pre-eclampsia, as being secondary to endothelial cell activation caused by circulating STBM shed in excess amounts from the placenta.     

Prostate cancer old problems and new approaches

Rates of prostate cancer (PCa) have increased so dramatically over the last decade that the age adjusted incidence rate for PCa is now greater than that any other cancer among men in the United States. This review, published as a three part series, provides a state-of-art assessment of the PCa problem in its divergent aspects.Part 1 covers epidemiology, incidence and progression. Several epidemiological studies have demostrated that first degree male relatives of men with PCa are at increased risk of developing the disease. Familial and genetic factors as well as medical, anthropometric, dietary, hormonal and occupational factors involved in PCa are discussed. Postmortem examination of the prostate in men without evidence of PCa documented a high frequency of adenocarcinoma. Latent disease occurred as early as the second decade of life. Although there is no significant difference in incidence between Caucasian and African-American males, high grade prostatic intraepithelial neoplasia (HGPIN) is higher in the latter group. While dietary fat, androgens and certain environmental factors may be determinants for PCa, the exact mechanism of tumorigenesis is still relatively unknown. The current thinking of the role of genomic instability, chromosomal alterations, tumor suppressor genes and the androgen receptor are explored.     

Osteoma of the thyroid cartilage--an unusual cause of difficult intubation

We describe a case of histologically proven osteoma of the thyroid cartilage that presented because of difficulty in intubation prior to coronary bypass surgery. To our knowledge, this is the first documented case in the English literature.     

An atraumatic anatomic technique for separation of the pediatric hernia sac from the spermatic cord

A detailed photographically illustrated anatomic technique for the sequential dissection of the pediatric hernia sac from the spermatic cord has not been described. An illustrated technique to atraumatically dissect the hernia sac in a systematic fashion is therefore presented.     

An anterior extraperitoneal incision for donor nephrectomy that spares the rectus abdominis muscle and anterior abdominal wall nerves

PURPOSE: To perform open donor nephrectomy with the least amount of body alteration and complication, a short extraperitoneal incision was developed that preserves the ipsilateral rectus abdominis muscle and abdominal branches of the intercostal nerves. MATERIALS AND METHODS: Donor nephrectomy using the new incision was performed in 11 consecutive patients. RESULTS: Morphine was required for pain relief for 1 to 3 days (mean 1.8), patients tolerated diet at 1 to 4 days (mean 2.2) and postoperative stay was 2 to 5 days (mean 3.5). Complications were minimal, consisting of postoperative fever 1 day in duration. A viable kidney was provided for transplantation in each case. CONCLUSIONS: The extraperitoneal, rectus abdominis muscle and nerve sparing incision resulted in a short course of pain medication, early diet toleration and a short hospital stay.