Aspects of the Central Integration of Arterial Baroreceptor and Cardiac Ventricular Receptor Reflexes in the Cat

The possible central integrative mechanisms, responsible for the earlier reported, differentiated reflex engagement of the renal and muscle vessels and the heart from cardiac ventricular receptors and arterial baroreceptors, respectively, were analyzed in atropinized cats. The reflex renal vessel, muscle vessel and heart rate responses, expressed as per cent of maximum, to graded activations of arterial baroreceptors (sinus pressure variations) and stimulations of ventricular receptor afferents in the cardiac nerve were systematically compared. Cardiac nerve stimulation with low frequencies was found to elicit more pronounced reflex renal vessel responses than muscle vessel and heart rate responses. In contrast, elevations of sinus pressure induced equally pronounced renal and muscle vessel responses. High frequency cardiac nerve stimulation elicited maximal reflex renal vessel responses, but only submaximal effects on muscle vessels and heart rate, while intense baroreceptor stimulation induced maximal reflex effector responses throughout. The submaximal heart rate response to cardiac nerve stimulation is probably due to a simultaneous activation of excitatory afferents. On the other hand, the less pronounced muscle than renal vessel responses when the cardiac nerve was stimulated probably reflect a relatively sparse innervation of muscle vasomotor neurons by ventricular receptor afferents, which seem instead to be preferentially oriented towards renal vasomotor and, possibly, cardiac motor neurons.     

Detection of K-ras mutations in mucinous pancreatic duct hyperplasia from a patient with a family history of pancreatic carcinoma.

Mutations in the K-ras oncogene and in the p53 tumor suppressor gene are commonly identified in sporadic cases of pancreatic adenocarcinoma. Although these genes might serve as useful markers for early diagnosis of pancreatic carcinoma in patients at risk for the development of this disease, familial pancreatic carcinomas have not been studied for these mutations. We recently had the opportunity to examine a pancreas prophylactically removed from a patient with a strong family history of pancreatic carcinoma. This gave us the unique opportunity to study the early events in the development of familial adenocarcinoma of the pancreas. Histopathological examination of the pancreas revealed multifocal papillary and nonpapillary mucinous duct hyperplasia. Seven of these foci were microdissected and analyzed for K-ras and p53 mutations. The K-ras mutations were detected by combined mutant-enriched polymerase chain reaction-restriction fragment length polymorphism analysis and characterized further by allele-specific oligonucleotide hybridization. Five of the seven duct lesions harbored activating point mutations in codon 12 of K-ras; a G to A transition was found in four and a G to C transversion in one. In contrast, these lesions did not harbor detectable p53 mutations as determined by denaturing gradient gel electrophoresis of exons 5 to 8, nor was there overexpression of the p53 protein as determined by immunohistochemistry. These findings suggest that mutations in K-ras represent an early event in the pathogenesis of pancreatic carcinoma. In addition, monitoring of patients with a strong family history of pancreatic carcinoma for K-ras mutations may identify patients at risk for the development of invasive carcinoma.     

T lymphocytes in host defense against bacterial translocation from the gastrointestinal tract.

Flow cytofluorometric analyses of lymphocytes harvested from the mesenteric lymph node (MLN), mucosal epithelium, and lamina propria of C57BL/6 mice demonstrate that expression of alpha/beta or gamma/delta T-cell receptors (TCR) and CD4 or CD8 molecules by T lymphocytes in the intestinal immune system varies depending upon their anatomic location. The MLN contained equivalent numbers of CD4+ and CD8+ T cells, the vast majority of which were alpha/beta TCR positive (alpha/beta TCR+). The lamina propria T cells were predominantly CD4+ and alpha/beta TCR+, while the intestinal intraepithelial lymphocytes consisted of equivalent numbers of alpha/beta and gamma/delta T cells, the majority of which were CD8+. There were no significant changes in these T-cell phenotypic profiles when the mice were antibiotic decontaminated or monoassociated with Escherichia coli. Mice were depleted of CD4+ T cells and/or CD8+ T cells in vivo by intraperitoneal injections of monoclonal antibody GK 1.5 (rat anti-mouse CD4) and/or monoclonal antibody 2.43 (rat anti-mouse CD8). T-cell depletion was confirmed in the MLN, lamina propria, and the intestinal epithelium by flow cytometry. E. coli C25 translocation from the gastrointestinal (GI) tract to the MLN was significantly increased in mice depleted of CD4+ T cells, CD8+ T cells, or both. T-cell-deficient athymic beige/nude mice also exhibited greater levels of E. coli C25 translocation to the MLN than beige/het euthymic littermates. Salmonella typhimurium translocation also was increased following CD4+ and CD8+ T-cell depletion in mice monoassociated with S. typhimurium. Depletion of CD4+ and/or CD8+ T cells also increased the translocation to the MLN of certain indigenous GI flora bacteria. These results confirm that T-cell-mediated immunity is involved in the host defense against bacterial translocation from the GI tract.     

Delineation of an estimated 6.7 MB candidate interval for an anophthalmia gene at 3q26.33-q28 and description of the syndrome associated with visible chromosome deletions of this region

Anophthalmia or microphthalmia occur in approximately one in 10 children who have severe visual impairment. These eye malformations are often of unknown aetiology, but can be inherited in autosomal dominant, recessive or X-linked forms, and can also occur in association with specific chromosome abnormalities. Four children are described in the medical literature with microphthalmia or anophthalmia in association with chromosome rearrangements involving distal 3q, suggesting the presence of a micro/anophthalmia gene in this region. We have identified two further patients with micro/anophthalmia and chromosome rearrangements involving 3q26-->3q27 and identified a 6.7 MB common deleted region. Patient 1 had multiple abnormalities including bilateral anophthalmia, abnormalities of the first and second cranial nerves and partial absence of the corpus callosum. His karyotype was 46,XY,del(3)(q26.33q28). Patient 2 had right anophthalmia and left extreme microphthalmia. Her karyotype was 46,XX,del(3)(q26.33q28)t(3;7)(q28;q21.1). Both patients had intrauterine growth retardation (IUGR) and strikingly similar dysmorphic facies consisting of bossed forehead, downward-slanting palpebral fissures, grooved bridge of the nose, prominent low-set ears, small down-turned mouth and small mandible. We identified BAC clones mapping to distal 3q from the ENSEMBL and NCBI Entrez databases. These BAC clones were used as fluorescence in situ hybridisation (FISH) probes to identify the minimum deleted region common to both patients. This interval, between clones RPC11-134F2 and RPC11-132N15, was estimated to be 6.7 MB. We conclude that there is an anophthalmia locus within this interval. Candidate genes mapping to this region include Chordin and DVL3, a homologue of the Drosophila Dishevelled gene.     

Falloposcopy in conjunction with laparoscopy: possibilities and limitations

Falloposcopy is a transvaginal microendoscopic technique to explore the human Fallopian tube from the uterotubal ostium to the fimbrial end. Falloposcopy provides a unique possibility to visualize endotubal disease and may be used therapeutically for removal of debris and for cutting down filmy intraluminal adhesions. To assess the clinical performance of falloposcopy as part of an infertility investigation, a total of 43 women scheduled for laparoscopy as part of an investigation of infertility had a falloposcopy performed in conjunction with the laparoscopy. All women were investigated at Danderyd Hospital, Stockholm and Akademiska Hospital, Uppsala, during 1995 and 1996. Images from the endosalpinx were obtained in 26 of 43 women (60.5%). In 10 women (23.3%), it was possible to obtain images from both tubes. No images were of sufficient quality to describe the entire tubal mucosa in detail. Falloposcopy represents a unique tool for visualization of endotubal disease and may provide a valuable instrument for in-vivo exploration of tubal physiology. However, certain technical problems limit the usefulness of this method in routine clinical practice. These technical problems have to be solved before falloposcopy can achieve a central position in investigation and treatment of tubal disease.      

Chloroquine interaction with inflammatory human polymorphonuclear leucocytes

The molecularin vitro association of radiolabelled chloroquine (CQ) with both normal resting and inflammatory polymorphonuclear leucocytes (PMNs) was measured. For this purpose a suitable ligandassocation assay was developed to measure the cell association and the intracellular concentration of CQ. Under the influence of inflammatory stimuli PMNs display altered interaction with CQ. The intracellular concentration of CQ is reduced with 30 to 40% under inflammatory (disease) states when compared with non-inflammatory conditions. The mechanisms of CQ-PMN interaction associated with these altered intracellular concentrations of CQ are considered, with particular attention to the effects of rheumatic disease. Association experiments of CQ with PMNs performed in the presence of different established transport inhibitors showed that both diffusive uptake and carrier-mediated transport are involved in the cell accumulation of CQ in inflammatory PMNs. From these results, emphasis is given to three explanations for the decrease of the intracellular CQ concentration in inflamed PMNs:

1. the expansion of the PMN volume under inflammatory conditions;
2. the cytoplasmic or lysosomal pH changes and activation of the PMN Na⁺/H⁺ antiport by inflammatory stimuli; and
3. the exocytic release of the granules (degranulation).

Our data suggest that all these mechanisms, based on the events involved in inflammatory responses, may be involved in the decrease of the intracellular CQ concentration in inflammatory PMNs.     

Catecholamine release after physical exercise. A new provocative test for early diagnosis of pheochromocytoma in multiple endocrine neoplasia type 2

A simple and practical provocative test is needed for early asymptomatic pheochromocytoma, which is a major risk for patients with multiple endocrine neoplasia type 2 (MEN-2). We measured plasma catecholamines before and after submaximal exercise in 26 MEN-2 gene carriers, eight of whom with asymptomatic pheochromocytoma, nine with medullary thyroid carcinoma and 10 after uni- or bilateral adrenalectomy. Seventeen clinically healthy individuals and 11 patients with neurovegetative lability and symptoms mimicking pheochromocytoma served as controls. Plasma adrenaline, noradrenaline and dopamine increased after exercise except for adrenaline after bilateral adrenalectomy. The post-exercise levels of adrenaline and the adrenaline/dopamine ratio were significantly higher in the pheochromocytoma patients compared to the healthy controls and the patients with neurovegetative lability, while the patients with medullary thyroid carcinoma represented an intermediate group with a high probability of developing adrenal tumors. The present method is a physiological test with a high sensitivity and specificity. It is practical and well suited for repeated examinations and seems to be of value for the detection of early pheochromocytoma in MEN-2 patients. Furthermore, the test could be used in the differential diagnosis between pheochromocytoma and neurovegetative lability.     

Congenital clubfoot in Europe: A population‐based study

We aimed to assess prevalence, birth outcome, associated anomalies and prenatal diagnosis of congenital clubfoot in Europe using data from the EUROCAT network, and to validate the recording of congenital clubfoot as a major congenital anomaly by EUROCAT registries. Cases of congenital clubfoot were included from 18 EUROCAT registries covering more than 4.8 million births in 1995–2011. Cases without chromosomal anomalies born during 2005–2009, were randomly selected for validation using a questionnaire on diagnostic details and treatment. There was 5,458 congenital clubfoot cases of which 5,056 (93%) were liveborn infants. Total prevalence of congenital clubfoot was 1.13 per 1,000 births (95% CI 1.10–1.16). Prevalence of congenital clubfoot without chromosomal anomaly was 1.08 per 1,000 births (95% CI 1.05–1.11) and prevalence of isolated congenital clubfoot was 0.92 per 1,000 births (95% CI 0.90–0.95), both with decreasing trends over time and large variations in prevalence by registry. The majority of cases were isolated congenital clubfoot (82%) and 11% had associated major congenital anomalies. Prenatal detection rate of isolated congenital clubfoot was 22% and increased over time. Among 301 validated congenital clubfoot cases, diagnosis was confirmed for 286 (95%). In conclusion, this large population‐based study found a decreasing trend of congenital clubfoot in Europe after 1999–2002, an increasing prenatal detection rate, and a high standard of coding of congenital clubfoot in EUROCAT.     

A 9.6 kilobase deletion in the low density lipoprotein receptor gene in Norwegian familial hypercholesterolemia subjects

Haplotype analysis of the low density lipoprotein receptor (LDLR) gene was performed in Norwegian subjects heterozygous for familial hypercholesterolemia (FH). Southern blot analysis of genomic DNA, using an exon 18 specific probe and the restriction enzyme NcoI, showed that two out of 57 unrelated FH subjects had an abnormal 3.6 kb band. Further analyses revealed that this abnormal band was due to a 9.6 kb deletion that included exons 16 and 17. The 5' deletion breakpoint was after 245 bp of intron 15, and the 3' deletion breakpoint was in exon 18 after nucleotide 3390 of cDNA. Thus, both the membrane-spanning and cytoplasmatic domains of the receptor had been deleted. A polymerase chain reaction (PCR) method was developed to identify this deletion among other Norwegian FH subjects. As a result of this screening one additional subject was found out of 124 subjects screened. Thus, three out of 181 (1.7%) unrelated Norwegian FH subject possessed this deletion. The deletion was found on the same haplotype in the three unrelated subjects, suggesting a common mutagenic event. The deletion is identical to a deletion (FH-Helsinki) that is very common among Finnish FH subjects. However, it is not yet known whether the mutations evolved separately in the two countries.