Topography of the cortico-cortical connections from the striate cortex in the cat

Injections of radioactive amino acids were placed in regions of the striate cortex of cat representing central, intermediate and peripheral parts of the horizontal meridian and also in regions of lower and upper visual field representations near the vertical meridian. The study of cortico-cortical connections arising from these points revealed several retinotopic arrangements in the distribution of these connections and, it is argued, of the extrastriate cortical recipient areas themselves. On retinotopic distribution exists along the banks of the middle suprasylvian sulcus, in which lower and upper visual fields are rostral and caudal, respectively, and central and peripheral visual fields are ventral (or lateral) and dorsal (or medial), respectively, in the banks. This arrangement is called the lateral suprasylvian area (LS). Another retinotopic distribution exists along the caudal bank of the posterior suprasylvian sulcus. In this region, called the posteroior suprasylvania area(PS), points at, or near, the horizontal meridian are mainly represented, central and peripheral parts of which are located dorsaly and ventrally in the sulcus, respectively. Two other retinotopic distributions of connected exist in visual areas 2(V2) and 3 (V3) of Hubel and Wiesel, in which lower and upper visual fields are situated rostrally and caudally in these areas, respectively. Along the horizontal meridian, central is lateral in V3 and medial in V2, while more peripheral points, (15 degrees, 45 degrees) of V3 and V2 approach each other, in a mirror image fashion, along the coronal plane. However, representations of these peripheral parts of the horizontal meridian are repeated twice again: extensively, caudally along the lateral border of area 18, and more restrictively rostrally, along the lateral border of area 18.     

Age-related increase in an advanced glycation end product in penile tissue

Nonenzymatic glycosylation (glycation) of proteins, often referred to as the Maillard reaction, has been proposed to play a role in age and diabetes-related processes by forming protein and DNA adducts and cross-links. These cross-links may contribute to erectile dysfunction by scavenging nitric oxide, which is needed for erection. As the basis for a possible role of the advanced Maillard reaction in age-related erectile dysfunction, we investigated the presence of the specific advanced glycation endproduct (AGE) pentosidine in penile corpus cavernosum tissue and penile tunica albuginea tissue as a function of age. A total of 23 penile tissue specimens were obtained at autopsy, from which 19 samples of tunica albuginea and 21 samples of corpus cavernosum were derived. In addition, 13 penile corporal and tunical specimens were procured at the time of insertion of a penile prosthesis, from which 12 tunica albugineal specimens and 10 samples of corpus cavernosum were derived. Collagen was extracted with acetic acid and pepsin digestion, and the final insoluble collagen product was acid-hydrolyzed with 6 N HCL for 24 h at 110 degrees C. Pentosidine was quantified by high-performance liquid chromatography using a reverse-phase column. The level of pentosidine (expressed in picomoles per milligram of insoluble collagen) was found to increase with age in cadaver as well as living penile corporal and tunical albugineal tissues. Best-fit analysis revealed an exponential increase in both types of cadaver penile tissue, with regression equations of y = 15.29 x 10(9.9e-3x), R2 = 0.79, being obtained in the tunica and y = 13.2 x 10(7.63e-3x), R2 = 0.56, in the corpora. These correspond to 6- and 4-fold increases in pentosidine levels from puberty to the age of 100 years (P < 0.05), respectively. Mean pentosidine levels were higher in the tunica than in the corpora. Comparison of pentosidine levels in the tunica versus the corpora revealed a weakly linear correlation (y = 24.88 + 1.08x, R2 = 0.32). Levels in the tunical and corporal specimens from the living human specimens fell with the predicted confidence intervals of the cadaveric tissue. Tunical specimens from patients who underwent repair or revision of a previously inserted penile prosthesis had very low levels of pentosidine. The exponential age-related increase in pentosidine observed in both types of penile tissue suggests an impairment of collagen turnover, which could be related to the advanced glycation reaction in aging. It is not known whether pentosidine itself is directly associated with erectile dysfunction, but its formation is usually accompanied by extensive tissue modification. Formation of advanced Maillard reaction products, which is greatly accelerated in aging, diabetes, and uremia, could contribute to erectile dysfunction in these syndromes.     

Severe attenuation of the B cell immune response in Msh2-deficient mice

Recently, results obtained from mice with targeted inactivations of postreplication DNA mismatch repair (MMR) genes have been interpreted to demonstrate a direct role for MMR in antibody variable (V) gene hypermutation. Here we show that mice that do not express the MMR factor Msh2 have wide-ranging defects in antigen-driven B cell responses. These include lack of progression of the germinal center (GC) reaction associated with increased intra-GC apoptosis, severely diminished antigen-specific immunoglobulin G responses, and near absence of anamnestic responses. Mice heterozygous for the Msh2 deficiency display an "intermediate" phenotype in these regards, suggesting that normal levels of Msh2 expression are critical for the B cell response. Interpretation of the impact of an MMR deficiency on the mechanism of V gene somatic hypermutation could be easily confounded by these perturbations.     

Multiple ventricular septal defects: how and when should they be repaired?

BACKGROUND: Congenital heart lesions with multiple ventricular septal defects remain a surgical challenge. Traditional approaches often rely on either ventriculotomy for exposure or palliation with pulmonary artery banding. However, indications for repair versus palliation and for various approaches to surgical exposure are not clearly defined. METHODS: From July 1992 to January 1998, 45 patients with multiple (>/=2) ventricular septal defects (37 with associated lesions) underwent surgery. Median age was 86 days; all but 4 patients were infants. The mean number of defects was 3.7, and almost half of the patients had more than 3 defects. Apical muscular defects were present in 62% of patients. Thirty-one patients underwent primary complete repair through a right atriotomy or trans-semilunar valve approach (group 1), 8 had palliation (group 2), and 6 underwent complete repair after prior palliation elsewhere (group 3). No patient had a ventriculotomy. RESULTS: One early death occurred in a group 1 patient. Four patients who had had palliation (50%) underwent early reoperation for pulmonary artery band revision because of failure to thrive or band removal after spontaneous closure of the defects. At follow-up (median 22 months), there was 1 death in a group 2 patient (palliation) and 1 other group 2 patient required cardiac transplantation. The only late reoperation was for removal of the pulmonary artery band and closure of multiple apical defects in a group 2 (palliation) patient. No patients who underwent repair have hemodynamically significant residual defects. CONCLUSIONS: In our experience, palliation of multiple ventricular septal defects is associated with greater morbidity than primary repair. Multiple defects can almost always be repaired adequately in early infancy without ventriculotomy, although "Swiss-cheese" septum may be an indication for palliation.     

Practice patterns of radiologists and nonradiologists: nationwide Medicare data on the performance of chest and skeletal radiography and abdominal and pelvic sonography

There are four types of symptoms on exposure to cold in the condition known as cold intolerance: pain/discomfort, stiffness, altered sensibility and colour change. They may occur in isolation or in any combination. Symptoms were present in at least 64% of 200 patients 24 months after hand injury. Pain was found to be the most troublesome symptom. Colour change in the digits was regarded by patients as the least troublesome symptom. Symptoms may begin immediately after injury, but are more likely to develop with the first onset of cold weather if there is a lag period between injury and onset. Pre-existing cold related symptoms are uniformly made worse by hand injury. A definition of the condition has been proposed and it has been suggested that this collection of symptoms be known as "Trauma Induced Cold Associated Symptoms".