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PubMed1983

Basic aspects of development and maturation of the brain: embryological contributions to neuroendocrinology.

The interpretation of studies on the development of neuroendocrine function presupposes a thorough knowledge of the complementary phenomena of morphogenesis and histogenesis of the brain. A short analysis of the morphogenesis of the diencephalic floor is given. The pituitary Anlage can be identified early in the neural plate stage. The hypophysis cerebri appears to be a key structure in the morphogenesis of both the head and the brain. The spatiotemporal pattern of histogenesis within the brain can be analysed by a study of the proliferative activity of the neuroepithelial matrix cell layer; a heterochrony of matrix (ventricular) layer mitotic activity and of mantle (intermediate) layer differentiation can be demonstrated. The process of neuron differentiation shows an articulate sequence of phenomena, among them migration, axon growth, dendrite growth, synapse formation and myelination. Dendritogenesis and the development of synapses in a particular area are strongly influenced by the ingrowth of axon nerve terminals from elsewhere. A number of structures observed in the developing central nervous system are only temporary phenomena that go into regression during subsequent stages; dendrites and synapses especially show a high degree of plasticity. Cell death occurs as a normal concomitant of development. Monoaminergic neuron systems originate early and show a positive histofluorescence shortly afterwards; their target areas are retarded as far as differentiation is concerned. The development of these target regions probably is influenced by the monoaminergic cells. The monoaminergic neurons are not subject to feedback regulation for some time, because of the typical late development of the dendritic receptive apparatus in these cells. Steroid receptors may play a role in the development of intersexual dimorphism of the brain. Probably a modulation of neurotransmitter synthesis is the intermediate between steroid receptor stimulation and a change in synaptogenesis in the target area of the neuron. Neuropeptide systems appear to possess a distribution beyond the limits of the hypophysiotropic area. The early presence of some of the neuropeptides within the embryonic brain suggests a role in histogenesis that is different from the usually presumed neurotransmitter or neuromodulator function of the neuropeptides.

Animals↗
PubMed1993

Studies on the safety of intrasplenic hepatocyte transplantation: relevance to ex vivo gene therapy and liver repopulation in acute hepatic failure.

Hepatocytes transplanted into the host liver engraft promptly, retain normal function, and survive indefinitely. Although intrasplenic transplantation is effective in delivering hepatocytes to the liver, to define potentially limiting complications, we studied its safety in normal, cirrhotic, and partial portal vein-ligated rats. In normal rats, portal pressures increased severalfold after hepatocyte transplantation but returned to normal within 3 weeks. In contrast, in portal hypertensive rats with partial portal vein ligation or cirrhosis, portal pressures were either unchanged or increased less after hepatocyte transplantation. However, more transplanted cells migrated to the lungs along with a rise in right atrial pressures in portal hypertensive rats. Further quantitative studies using 111Indium-labeled hepatocytes showed that intrasplenic retention of transplanted hepatocytes was similar in all animal groups. Intrahepatic cell translocation was comparable in normal and cirrhotic rats, whereas fewer cells migrated to the liver in partial portal vein-ligated rats. The most remarkable difference, however, was significantly greater intrapulmonary translocation of hepatocytes in portal hypertensive rats, which was presumably related to portosystemic shunting. These results indicate that because intrasplenic hepatocyte transplantation induces only temporary portal hypertension in normal subjects, potential strategies to augment liver repopulation could include repeated cell transplantation. This should be useful for optimizing the results of ex vivo gene therapy, or other hepatocyte-based therapies. However, the hepatic and portal hemodynamic status requires careful evaluation in portal hypertensive or cirrhotic subjects if serious complications are to be avoided.

Animals↗
PubMed2005

Long lives, short indications. The case for removable inferior cava filters.

Vena cava filters have been in use for decades to prevent pulmonary embolization from deep venous thrombosis. These filters have been shown to be effective, with fairly low rates of filter migration, fracture and thrombosis. However considering that filters remain in situ for the life of the patient and that studies do not show increased longevity in patients with filters, any complications from filters are significant concerns. In addition, often patients require filters for only temporary indications, e.g. contraindication for anticoagulation because of impending procedures, or for only a transient risk period, as in trauma or pregnant patients. In these cases, removable filters may be more appealing. This review will examine the different types of removable filters and the indications in which removable filters may have an advantage over permanent filters.

Disposable Equipment↗
PubMed1977

Neutrophil preservation: the effect of short-term storage on in vivo kinetics.

A rabbit model was developed to study the in vivo viability of neutrophils stored in vitro for up to 72 h. Acid-citrate-dextrose anticoagulated whole blood was obtained from rabbits previously injected with tritiated thymidine ([3H]thymidine), stored under varying conditions, and then injected into recipient rabbits. Neutrophil viability and function were assessed by measuring the ability of the tagged neutrophils to circulate and to migrate into subcutaneous polyvinyl sponges. Unstored neutrophils disappeared exponentially from the circulation with a t1/2 of 3.2 h and gave a zero time recovery of 30.5%. Storage of cells at either room temperature or 4 degrees C for 24 h or longer resulted in temporary sequestration of cells from active circulation. With cells stored for up to 72 h at 4 degrees C, recovery returned to normal values after 1-2 h. Room temperature stored cells, in contrast, showed evidence of irreversible damage at 48-h storage with low recovery for the entire time span studied. With unstored blood, 8.1+/-0.9% of the injected neutrophil label was present in the subcutaneous sponges. The accumulated label progressively decreased as cell storage time increased reaching at 72 h 5.1+/-0.6 and 2.6+/-0.3% for 4 degrees C and room temperature-stored cells, respectively. The results of this study indicate that 4 degrees C storage of rabbit neutrophils is superior to storage at room temperature. The data suggest that it may be feasible to store neutrophils at least a few days without loss of in vivo functions.

Animals↗
PubMedDate not supplied

[Intestinal obstruction by biliary ileus; clinical experience and literature review].

BACKGROUND: Gallstone ileus is an unusual and peculiar complication of biliary lithiasis. Less than 1% of gallstones migrate into the gut, causing 25% of non-strangulated small bowell obstructions in elderly population. Diagnosis is difficult, leading to late operation. Considering the median age of the patients and the fact that in most cases surgery is delayed, there is a lot of dispute regarding the best approach. Recent technical facilities in diagnostic and surgical practice seem to be irrelevant for the general outcome. MATERIAL AND METHOD: All 6 patients operated since 1981 (median age 67 years, 5 female) were retrospectively analyzed, to determine the most valid option. Biliary ileus was recorded in 0.16% of all operations for billiard lithiasis and 1.52% of all enteric occlusions. There was a mean delay of 4.2 days for onset of symptoms to admission and further 5 days to surgery. Particular elements suggesting the ethiology were absent in most cases. In all cases the gallstone migrated in the duodenum. The obstruction was jejunal (3 patients), proximal ileal (2 patients) and distal ileal (1 patient). Enterolithotomy was practiced in 3 cases, with subsequent cholecystectomy and fistula closure in 1 case; one-stage repair in 2 cases and enterolithotomy with temporary external drainage of the fistula (cholecystostomy) in 1 patient. RESULTS AND CONCLUSIONS: There were no specific (fistular) complications; 1 aged patient with distal occlusion died because of severe metabolic disorders. The most "favourable" cases were those with very large gallstones occluding the jejunum. Smaller stones were less symptomatic, resulting in delayed diagnosis and surgery; the more aboral the occlusion, more indication for abstention regarding primary repair of the fistula.

Aged↗
PubMed1989

Current trends in malaria in Britain.

Malaria is already present in Britain with an average of 1843 cases reported annually in the last decade. The vast majority are imported cases who have acquired the infection elsewhere but have become ill in the United Kingdom. However, minute numbers are acquired either congenitally (transplacentally) from their infected (but often asymptomatic) mothers; or by blood transfusion, though this is almost wholly prevented now; or from mosquitoes, infected with malaria, which have succeeded in stowing away on aeroplanes in the tropics and surviving to bite man on emerging from the aircraft on landing. Two such cases, near Gatwick, have been reported in the UK but larger numbers have occurred around continental airports. Imported malaria has shown a complex pattern over the last three decades for there have been a series of temporary increases, from population movements due to wars and immigration, superimposed on longer term trends. The determinants of the levels of imported malaria are three: the level of transmission or endemicity in the tropical and subtropical areas where malaria is contracted; the amount of migration to endemic areas by British residents, that is exposure, and of travel to Britain by nationals of endemic areas; and, thirdly, the success or otherwise of attempts at prophylaxis by avoiding mosquito bites and taking antimalarial drugs. We can measure endemicity by epidemiological study in warm climate countries; exposure (to a first approximation) by means of travel statistics; and the effective risk (when preventive measures have been taken to a variable degree) by recording the number of cases actually detected in the UK.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

New retrievable percutaneous vena cava filter: experimental in vitro and in vivo evaluation.

A new retrievable percutaneous vena cava filter was tested in vitro and in vivo in 15 foxhounds. In vitro, the new vena cava filter was compared with the standard Kimray-Greenfield filter and the Günther basket filter. The new filter is a stainless steel half-basket filter and is suitable for percutaneous antegrade or retrograde insertion through a 8.5 Fr introducer sheath. In vitro testing showed the filter causing no significant flow alterations and being highly effective in capturing medium- and large-sized thrombi; furthermore, fatigue testing revealed no breakage of the new filter, whereas the Günther basket filter showed breakage of the struts. In vivo studies showed no occlusion, major perforation, or filter migration during follow-up of 2 weeks to 6 months. Tilting of the filter postimplantation occurred in two out of 28 filters. Ten of 11 filters were successfully retrieved by the transjugular approach 2 weeks after implantation. The device seems to be suitable for temporary or permanent protection against pulmonary embolism.

Animals↗
PubMed2006

Selected best demonstrated practices in peritoneal dialysis access.

Many burdensome interventions that adversely affect the utilization of peritoneal dialysis as renal replacement therapy and patient satisfaction with this treatment modality can be avoided by early peritoneal access placement with embedded catheters, implantation techniques that preempt common catheter complications, and the use of access devices that provide flexibility in exit site location. Catheter embedding consists of subcutaneously burying the external limb of the catheter tubing at the time of the insertion procedure. Interval exteriorization of the catheter is performed when dialysis is needed. Earlier commitment by patients to peritoneal dialysis can be achieved by elimination of catheter maintenance until dialysis is necessary. Catheter embedding is a practical strategy to avoid temporary hemodialysis with vascular catheters and reduces stress on operating room access by allowing more efficient scheduling as non-urgent procedures. Laparoscopic catheter placement enables proactive techniques not available to other conventional insertion methods. These techniques include rectus sheath tunneling to prevent catheter tip migration, selective prophylactic omentopexy to prevent omental entrapment, selective resection of epiploic appendages to prevent catheter obstruction, adhesiolysis to eliminate compartmentalization, and diagnosis and simultaneous repair of previously undiagnosed abdominal wall hernias. Both standard and extended 2-piece catheter systems are necessary to customize the peritoneal access to a variety of body configurations. Catheters should be able to produce lower abdominal, mid-abdominal, upper abdominal, and upper chest exit site locations that facilitate management by the patient without sacrificing deep pelvic position of the catheter tip or resulting in excessive tubing stress during passage through the abdominal wall.

Benchmarking↗
PubMed2003

How to manage acute urethral false passage due to intermittent catheterization in spinal cord injured patients who refused insertion of an indwelling catheter.

PURPOSE: Acute urethral false passage is an important complication of clean intermittent catheterization in spinal cord injured patients. Temporary urethral stenting with an indwelling catheter is generally an excellent conventional therapeutic option to treat patients with acute false passage. However, how can acute false passage be managed in a patient who refuses insertion of an indwelling catheter? MATERIALS AND METHODS: For 3 years 5 male patients with acute urethral false passage due to catheterization refused urethral stenting because indwelling catheter insertion would prevent sexual intercourse. We placed a nitinol prostatic stent successfully in the false urethral passage in all 5 patients. The stents were left in place for 3 to 6 months. RESULTS: The stent migrated in 1 patient and it was replaced. During a retention period of 3 to 6 months all patients continued clean intermittent catheterization without any difficulty and achieved sexual intercourse. On urethral cystoscopy we observed that all false passages disappeared without a gross tissue reaction. The stents were then removed without any complications. During a mean followup of 11.8 months (range 4 to 25) none of these patients had another false passage. All continued to perform clean intermittent catheterization without any further difficulty. CONCLUSIONS: Temporary placement of a removable endourethral stent is a safe and effective method for managing acute urethral false passage in patients on clean intermittent catheterization who refuse insertion of an indwelling catheter. This approach makes further clean intermittent catheterization possible and improves patient quality of life.

Acute Disease↗
PubMed1996

[The European Union and the migrations of populations. Government logic and human rights].

"The first part of this article consists of a summary of the major [immigration] reforms undertaken by the EU [European Union] states over the past decade. The second chapter discusses the ways in which these reforms were drafted, and, in particular, the influence of intergovernmental negotiations on national policy. The third part, relative to the regulation of job markets, underscores the contrast between the tough restrictions on permanent employment of foreigners and flexibility...for administering seasonal immigration or entry visas granted within the context of temporary work contracts. The fourth part, which analyzes the impact of these legislative changes on individual rights, logically leads to a discussion of the foundation of the procedure followed by the wealthy countries, and points out the shortcoming of a strictly punitive or even military solution to what is chiefly a problem of development and democracy." (SUMMARY IN ENG AND SPA)

Demography↗
PubMed1995

Pathophysiology of pigment dispersion syndrome and pigmentary glaucoma.

Pigmentary glaucoma results from zonular-pigment dispersion, primarily in young, myopic, white individuals. The concavity of the midperipheral iris allows iridozonular contact. Released pigment is carried to the trabecular meshwork where it resides: (1) benignly, not affecting the intraocular pressure, as in pigment dispersion syndrome; or (2) malignantly, elevating the intraocular pressure, as in pigmentary glaucoma. Small amounts of pigment are quickly phagocytized. If the particulate load is heavy, the cells migrate further along the outflow pathway. The flattening of the iris in pigmentary glaucoma patients receiving iridotomies, along with the backward flow of pigment observed during treatment, demonstrates a greater pressure in the anterior than the posterior chamber. This reverse pupillary block may be due to temporary ocular deformations caused by blinking, as small aqueous aliquots are forced into the anterior chamber. Flattening of the concave iris is the key to current and future management of these patients.

Ciliary Body↗
PubMedDate not supplied

Can clamping of splenic vessels prevent abrupt increase of portal vein pressure and migration of transplanted hepatocytes to the liver after intrasplenic hepatocyte transplantation?

BACKGROUND/AIMS: It is well known that hepatocyte transplantation can retain some proper functions, significantly improve the survival rate of rats with different models of acute fulminant hepatic failure, correct some congenital genetic disorders, and improve liver function in cirrhosis. Portal hypertension and hepatic embolization have been described following intrasplenic hepatocyte transplantation. We evaluated the effect of temporary occlusion of splenic vessels on changes in portal vein pressure and on distribution of transplanted hepatocytes after hepatocyte transplantation into the spleen in normal rats. METHODOLOGY: Liver cirrhosis has been induced in rats by 1% dimethylnitrosamine (Sigma, St. Louis, Mo) dissolved in normal saline at the dose of 10 ml of DMN/Kg, i.p., 3 consecutive days a week for 4 weeks. Donor hepatocytes were harvested by in situ ethylenediaminetetraacetic acid (EDTA) perfusion. Changes in portal vein pressures were monitored by a pressure monitor and distribution of transplanted hepatocytes was assayed by measurement of radioactivity of 51Cr-labeled transplanted hepatocytes according to clamping or non-clamping during intrasplenic hepatocyte transplantation. RESULTS: The changes in portal pressure remained significantly high 10 min after hepatocyte transplantation in the nonocclusion groups compared to the occlusion groups. However, the changes in portal vein pressures in cirrhotic rats returned to normal faster than in normal rats after cell transplantation in the nonocclusion groups. The distribution of 51Cr-labeled transplanted hepatocytes into the spleen significantly diminished radioactivity of the liver at 10 min, 2 hours, and 24 hours in the occlusion groups compared to the nonocclusion groups. Also, duration of clamping time of splenic vessels did not influence the initial distribution of transplanted hepatocytes at the time of intrasplenic hepatocyte injection. CONCLUSIONS: These results suggested that temporary occlusion of splenic vessels should be routinely used during intrasplenic hepatocyte transplantation.

Animals↗
PubMed1991

Reduction of central nervous system ischemic injury by monoclonal antibody to intercellular adhesion molecule.

Activated leukocytes appear to be directly involved in potentiating ischemic central nervous system (CNS) injury. Adhesion of leukocytes to endothelium is essential for their migration and requires the binding of adhesion receptors of the leukocyte (CD 18) to an intercellular adhesion molecule (ICAM) on endothelium. Monoclonal antibodies to an ICAM can block leukocyte adhesion and transendothelial migration. To determine the efficacy of anti-ICAM antibody treatment in preserving neurological function after CNS ischemia, two animal models were used. A 1-mg/kg dose of anti-ICAM was given to rabbits 30 minutes before induction of ischemia either in the spinal cord using temporary aortic occlusion or in the brain using intra-arterial microspheres. In this study, treatment with anti-ICAM produced a significant reduction in neurological deficits in the reversible spinal cord ischemia model but not in the irreversible brain ischemia model. This protective effect supports the active role of leukocytes in CNS reperfusion ischemic injury and offers potential for future therapy.

Animals↗
PubMed2003

Treatment of thoracoabdominal aortic aneurysms with a combined endovascular and surgical approach.

AIM: The conventional approach for the repair of thoracoabdominal aneurysms remains complex and demanding and is associated with substantial morbidity and mortality. Moreover, in cases of reoperation the impact can be dramatic either in survival or in quality of life of the patients, albeit the use of adjuncts. A combined endovascular and surgical approach with retrograde perfusion of visceral and renal vessels has been realized in order to minimize intraoperative and postoperative complications. METHODS: Within an experience of 231 aortic stent-grafts between 1995-2000, 4 of the patients with thoracoabdominal aneurysms were treated with a combined endovascular and surgical approach. Three procedures were electively conducted and 1 on emergency basis. Two women, 59 and 68 years old, and 2 men, 68 and 73 years old (maximum aneurysm's diameter was 10, 6, 8 and 9 cm, respectively) were operated with the combined method (the first 2 patients had a previous open repair of a thoracoabdominal aneurysm). The surgical approach was executed in all patients without thoracotomy or re-do retroperitoneal exposure. Revascularization of renal, superior mesenteric (and celiac in 2 cases) arteries was accomplished via transperitoneal bypass grafting. Aneurysmal exclusion was performed by stent-graft deployment. RESULTS: The entire procedure was technically successful in all patients. The 1(st) patient was discharged 6 weeks after the operation, while the postoperative studies revealed the patency of the vessels and no evidence of leak or secondary rupture of the aneurysm; the patient died 3 months after the repair, due to rupture of an aneurysm of the ascending aorta. In the 2(nd) patient, 30 months after the operation, spiral-CT scanning revealed distinct shrinkage of the aneurysm, no graft migration or endoleak and patency of all revascularized vessels. The 3(rd) patient died on the 6th postoperative day due to multiorgan failure after having developed ischemic-related pancreatitis, albeit the successful combined repair. The 4(th) patient followed an uneventful course. No patient experienced any temporary or permanent neurological deficit. CONCLUSION: The combined endovascular and surgical approach is feasible, without cross-clamping of the aorta and with minimized ischemia time for renal and visceral arteries, and seems the appropriate strategy for high risk and previously operated, with a thoracoabdominal trans-diaphragmatic approach, patients.

Aged↗
PubMedDate not supplied

The effect of early hypoxy upon the development of rats and mice. 1. Preimplantation effects.

The effect of temporary hypoxy obtained by uterine vascular clamping during the preimplantation developmental period, was controlled on rats and mice (on the last day of preimplantation development). The following main effects were detected: retarded preimplantation development in rats; increased number of pathologically modified embryos and retarded oviduct-uterus migration in both species. The changes of the uterine wall due to vascular clamping disappear two days after the experimental intervention. The existence of an experimental hypoxic blastopathy is attested (at least its early, preimplantation aspect).

Animals↗
PubMedDate not supplied

Laser welding of synthetic epikeratoplasty lenticules to the cornea.

We used a milliwatt continuous wave CO2 laser mounted on an operating microscope to study the feasibility of welding synthetic collagen epikeratoplasty lenticules to the cornea. In vitro studies and experimentation in rabbits and monkeys showed no welding effects using direct laser radiation with powers ranging from 17 mW to 1 W. Only tissue shrinkage was observed. Experiments using various adjunctive solders produced a temporary welding effect using 30% bovine serum albumin welded with a power of 35-45 mW, 325 microns spot size, moving the beam 5 mm/sec. The lenticules remained in place until the 4th postoperative day when epithelium grew underneath the lenticule, dislodging it. Histopathologic examination demonstrated epithelial migration over the solder displacing the epikeratoplasty lenticule and anterior stromal denaturization and disruption.

Animals↗
PubMed2004

Endovascular management of juxtarenal aneurysms with fenestrated endovascular grafting.

PURPOSE: To evaluate the technical feasibility and short-term results of juxtarenal aneurysm repair with an endovascular graft that incorporated the visceral aortic segment with graft material. METHODS: Patients were studied prospectively after the implantation of an endovascular device with graft material extending proximal to the renal arteries, variably incorporating the superior mesenteric and celiac arteries. All patients were deemed to be high risk with respect to open surgical repair and had compromised proximal neck anatomy. Proximal neck lengths were <or=10 mm, or <or=15 mm with a challenging morphology (funnel shape or extensive thrombus). Fenestrations within the graft material were customized to accommodate visceral and renal vessels on the basis of computerized tomography (CT), angiography, or intravascular ultrasound data. Selected visceral ostia were protected with balloon-expandable stents after partial endograft deployment. All patients were evaluated with CT and kidney, ureters, and bladder x-ray at discharge and at 1, 6, and 12 months. Visceral duplex scan studies were performed at 1, 6, and 12 months. RESULTS: A total of 22 patients were enrolled in the study. Sixteen patients had short proximal necks (3-10 mm), and six had compromised necks of 10 to 15 mm in length. Endograft design included bifurcated (20) and tube (2) systems. All prostheses were implanted successfully without the acute loss of any visceral arteries. A total of 58 visceral vessels were incorporated (mean, 2.6 per patient) and most commonly included both renal arteries and the superior mesenteric artery. The mean follow-up was 6 months. There were no deaths within 30 days and no aneurysm-related deaths during the follow-up period. Two early (<30 days) and two late secondary interventions were performed, inclusive of two visceral artery stenoses detected with duplex scanning. The 30-day endoleak rate was 4.5%. The aneurysm sac decreased greater than 5 mm in 53 % of patients at 6 months and three of four patients at 12 months. Three patients developed renal insufficiency, only one of which required temporary hemodialysis. CONCLUSIONS: The placement of an endovascular prosthesis with graft material that incorporates the visceral arteries is technically feasible. The occurrence of endoleaks appears to be relatively low. The increased sealing and fixation zones in this patient population should limit the late development of proximal endoleak or migration; however, this situation will require more patients and extended follow-up.

Aged↗
PubMedDate not supplied

Permanent cardiac pacemakers: issues relevant to the emergency physician, Part I.

Many people benefit from the implantation of cardiac pacemakers for management of certain cardiac dysrhythmias. These patients are seen regularly in the emergency department with a variety of pacemaker complications and malfunctions. The presence of a pacemaker may also affect management of unrelated medical problems. This two-part series reviews the medical issues related to patients with permanent pacemakers. Part I covers pacing modes and terminology, complications of the implant procedure, and the approach to a patient with a permanent pacemaker. Part II covers the causes, diagnosis and management of pacemaker malfunction; the pacemaker syndrome; the pacemaker Twiddler's syndrome; and other considerations in the paced patient including diagnosis of acute myocardial infarction, ACLS protocols, trauma, and sources of interference. Indications for permanent pacemaker implantation and temporary external pacing will not be covered.

Electrodes, Implanted↗