Systemic and luminal influences on the perinatal development of the gut

At birth, the mammalian gastrointestinal tract (GIT) must be able to support a shift from mainly parenteral nutrition in the fetus (via the placenta) to enteral nutrition in the neonate. In the perinatal period the GIT therefore undergoes enhanced growth as well as morphological and functional differentiation, and this maturational programme is influenced by a complex interplay of local, systemic and luminal factors. This review shows how systemic and luminal factors may influence GIT development in the perinatal period of the pig and sheep, two long-gestation species. Adrenocortical hormones play a pivotal role in the prepartum maturation of the GIT in addition to their better known effects on the development of many other tissues and body systems. More particularly, in the fetal pig and sheep, the prenatal development of gastric acid and gastrin secretion, and of GIT hydrolase activities (chymosin, pepsin, amylase, lactase, aminopeptidases) is influenced by cortisol. Additionally, glucocorticoids exert effects throughout the GIT by influencing morphological, cytological, and functional differentiation. Since the GIT epithelial cells comprise a renewing cell population there are also changes in cell kinetics. In addition to systemic factors, the presence of growth factors, hormones and nutrients from swallowed amniotic fluid (fetus) and colostrum (neonate) may influence GIT development. In utero, fetal fluid ingestion has been shown to modulate tissue growth, macromolecule and immunoglobulin transport, enterocyte differentiation, cell turnover and activity of brush-border hydrolases. These effects may be mediated via regulatory peptides (e.g. insulin-like growth factor I, gastrin-releasing peptides, insulin, epidermal growth factor, gastrin). A physiological role of luminally derived growth factors is supported by a number of unique structural and functional adaptations of the GIT in the fetus and neonate (low luminal proteolysis, intestinal macromolecule transport). Thus, in the pig and sheep, both systemic and luminal factors appear to play critical roles in GIT development in the perinatal period.     

The ecology of echo

Echo is a generic ecosystem model in which evolving agents are situated in a resource-limited environment. The Echo model is described, and the behavior of Echo is evaluated on two well-studied measures of ecological diversity: relative species abundance and the species-area scaling relation. In simulation experiments, these measures are used to compare the behavior of Echo with that of a neutral model, in which selection on agent genotypes is random. These simulations show that the evolutionary component of Echo makes a significant contribution to its behavior and that Echo shows good qualitative agreement with naturally occurring species abundance distributions and species-area scaling relations.     

Overexpression of Glut1 and Glut3 in stage I nonsmall cell lung carcinoma is associated with poor survival

We report the electrophysiologic findings of myoclonus in a patient with Huntington's disease (HD). This patient was studied postoperatively after a bilateral fetal cell transplant in his striatum. Incomplete transient improvement was seen in the myoclonus, followed by gradual deterioration. The myoclonus itself had a cortical correlate and was associated with an enlarged somatosensory evoked potential (SEP), consistent with the presence of cortical reflex myoclonus. An enlarged SEP has not been previously reported in myoclonus associated with HD. The postulated mechanisms for myoclonus, when it occurs in HD, have differed in the literature. The reason for the transient improvement of the myoclonus following transplantation is unclear, but this case raises the possibility that basal ganglia circuits may modulate cortical myoclonic activity.     

Meckel''s diverticulum presenting as gastric outlet obstruction: case report

We report a case of gastric outlet obstruction simulating gastric antral neoplasm resulting from a perforated Meckel's diverticulum. Presentation of this nature has not been previously reported.     

Extracorporeal photochemotherapy (photopheresis) induces apoptosis in lymphocytes: a possible mechanism of action of PUVA therapy

The mechanism of action of psoralen plus UVA (PUVA) and photopheresis is not entirely understood. These therapies are assumed to be immunomodulating partly by gradually decreasing leukocyte viability. We investigated whether this delayed form of cell death was due to apoptosis. Untreated and treated (PUVA exposed) leukocytes obtained from six patients with systemic sclerosis and (untreated) leukocytes from healthy control individuals were studied. Qualitative gel electrophoresis and quantitative in situ nick translation analysis of DNA fragmentation was performed. Apoptosis of the treated cells did occur (gel electrophoresis) after 24 h. At t = 0 h, immediately after exposure to PUVA, there was no evidence of DNA fragmentation in the treated cells. The percentage of treated cells undergoing apoptosis was 20-55% at t = 24 h (in situ nick translation). The untreated leukocytes of the patients and the healthy individuals showed no distinctive rise in apoptotic cells. Apoptosis of the leukocytes after PUVA or photopheresis treatment might be a mechanism of action and might explain the therapeutic response.     

立达C60型梳棉机使用经验

介绍了一印度尼西亚纺纱厂使用瑞士立达机械工程公司生产的C60型梳棉机在环锭细纱操作方面运转性能和质量的经验。     

Correlation of near infrared spectroscopy cerebral blood flow estimations and microsphere quantitations in newborn piglets

We compared cerebral blood flow (CBF) estimated using transmission mode near infrared spectroscopy (NIRS) and a modification of the Fick principle with CBF quantitations by radioactive microspheres (MSs) in newborn piglets. Thirteen piglets were studied during steady state, ischemia, and during two reflow periods. NIRS and MS flows were not significantly different during any measurement period. NIRS flows were compared to total brain blood flows and to regional brain blood flows quantitated with MSs and correlated best with temporal cortical flows. Linear regression analysis of the NIRS flows plotted against MS-quantitated temporal cortical flows showed r = 0.71. Thus, CBFs obtained with NIRS were not significantly different from, showed the same directional changes, and correlated acceptably with flows quantitated by MSs.     

Glucose effectiveness, peripheral and hepatic insulin sensitivity, in obese and lean prepubertal children

Vascular injuries in lumbar disk surgery, although rare, are serious complications which may be overlooked due to a broad range of clinical manifestations. It is important that surgeons and radiologists be aware of these potentially fatal complications and develop an appropriate symptom-based diagnostic paradigm. We reviewed 8099 consecutive cases of lumbar disk surgery, performed over a 14-year period at a single institution, for postoperative vascular complications. We identified four patients (0.05%) with lumbar disk surgery-related vascular complications: intraoperative lacerations of the abdominal aorta and median sacral artery, an arteriovenous fistula between the left common iliac artery and vein detected 19 days postdiskectomy, and a partially thrombosed aortic aneurysm with an arteriovenous fistula between the aneurysm and the inferior vena cava, diagnosed 11 months after surgery. The majority of cases in the literature of vascular injury in lumbar disk surgery were reported prior to 1965. Diagnostic approaches described in that period do not reflect the great range of diagnostic techniques available today. Angiography remains the gold standard for diagnosis and guidance as to surgical repair. However, a high index of suspicion based on clinical signs and/or the use of sonography or CT is important in the detection of these complications.     

Cloning and characterization of Schistosoma mansoni fructose-1,6-bisphosphate aldolase isoenzyme

A Schistosoma mansoni cercarial cDNA expression library, constructed in lambda gt11, was screened using the IgG fraction of sera taken from rabbits vaccinated with irradiated cercariae. A positive cDNA clone (1,431 base pairs) was selected and characterized. The amino acid sequence predicted from the cDNA sequence identified a polypeptide of 363 amino acids that showed significant homology to different family members of the enzyme fructose-1,6-bisphosphate aldolase (EC 1.4.2.13). The identity was 66% and 65% with human C and A isoenzymes, respectively. Active sites and substrate-binding determinant analysis suggest that the isolated enzyme in terms of function resembles type A aldolase. The recombinant protein expressed in the vector pGEX-2T was found to be active enzymatically. Antibodies raised against the purified recombinant protein recognized a 40-kDa band in extracts from cercariae, schistosomula (5 and 25 days), adult worms, and eggs. Using immunocytochemistry, aldolase localized to the tegumental region of the adult worms.