Fibrillogenesis in tendon healing: an experimental study

The aim of this study was the histochemical, immunohistochemical and ultrastructural analysis of reparative fibrillogenesis in experimental lesions of Achilles' tendon. Subtotal tenotomy of Achilles' tendon was performed in twenty Wistar rats. The scar tissue was analysed 2, 4, 7, 14, 21, 30, 45 and 60 days post-operatively. Histochemical, (resorcin-fuchsin, aldehyde-fuchsin, iron haematoxylin and Fullmer and Lillie's methods) immunohistochemical (antibody against collagen I, II and elastin) and ultrastructural analyses were performed. Three phases in the healing process were distinguished: 1) inflammatory, 2) proliferative, and 3) remodelling phase. The inflammatory phase was characterised by haematoma, fibrin deposition, inflammatory cells, fibroblasts, beginning of collagen fibrillogenesis (200-400 A ? fibrils) and oxytalan fibrils. The proliferative phase was characterised by angiogenesis and fibroblast proliferation. Collagen fibres displayed a random arrangement and had a diameter of 400-600 A. Immature elastic fibres reached maximum tissutal concentration. In the remodelling phase, hypocellularity, normal vascularisation, tendon crimps, collagen fibres (800-1,000 A ?), elastic fibres with increased elastin deposition and reduction in oxytalan fibres were observed. In the course of the healing process collagen and elastic fibre fibrillogenesis exhibited consistent quantitative and qualitative variations (i.e. differences in the type and diameter of fibrils). The present study suggests that, together with other matrix macromolecules, also elastic fibres (oxytalan, elaunin and mature) are synthesised in significantly higher amounts during reparative fibrillogenesis and play a role in cell-matrix interaction.     

In-home family-focused reunification: an experimental study

Intensive, in-home family-based services were employed in reunifying families separated by the placement of a child in out-of-home care. After a 90-day service period, 93% of the 57 families randomly assigned to receive the intensive treatment were reunited-compared to 28% of the 53 families in a control group who received routine out-of-home care services. Follow-up data were collected six and 12 months after the end of treatment. Estimates of outcomes suggest that the experimental treatment had a substantial impact on families and that treatment effects endured for upwards of 12 months following cessation of direct intervention services.     

The virulence gene cluster of Listeria monocytogenes is also present in Listeria ivanovii, an animal pathogen, and Listeria seeligeri, a nonpathogenic species

Most known Listeria monocytogenes virulence genes cluster within a 9.6-kb chromosomal region. This region is flanked on one end by two uncharacterized open reading frames (ORF A and ORF B) and ldh, an ORF presumably encoding the L. monocytogenes lactate dehydrogenase (J.-A. Vazquez-Boland, C. Kocks, S. Dramsi, H. Ohayon, C. Geoffroy, J. Mengaud, and P. Cossart, Infect. Immun. 60:219-230, 1992). We report here that the other end is flanked by prs, and ORF homologous to phosphoribosyl PPi synthetase genes. ORF B and prs were detected in all Listeria species and thus delimit the virulence region. This virulence gene cluster was detected exclusively in hemolytic Listeria species, Listeria ivanovii, an animal pathogen, and Listeria seeligeri, a nonpathogenic species.     

Vibrio cholerae adherence and colonization in experimental cholera: electron microscopic studies

Colonization of the intestinal epithelium by Vibrio cholerae was examined in two model systems, in ligated ileal loops of adult rabbits and in the patent gut of infant rabbits, using both scanning and transmission electron microscopy. Time studies in the adult model showed a lag period of up to 1 h before the attachment of significant numbers of the vibrios. The bacteria appeared initially in small patches on the sides of the villi, predominantly along the transverse furrows. The number of adherent bacteria steadily increased, reaching a maximum between 4 and 7 h, when a dense mat of bacteria several layers thick covered much of the villi. After this time there was a rapid decline in the number of V. cholerae bound. By 12 to 16 h only a few bacteria could be seen on the surface of the villi, which had a rough, patchy appearance at these later times. Globular protrusions, with vibrios attached, may play a role in the clearance of bacteria. Colonization and clearance in the patent intestine of the infant rabbit occurred much as in the adult model. However, the bacteria adhered more uniformly and there was no lag in attachment. In both models the majority of bacteria were aligned horizontally with the epithelial surface, but some were attached in an end-on manner, with their flagella extending into the lumen. The bacteria adhered via their surface coats directly to the tips of the microvilli, except for a few vibrios that were partly embedded into the brush border. Some changes in the microvilli occurred as a consequence of the bacterial attachment.     

Psychiatry and dermatologic neoplasms: results of an experimental study

Psycho-oncology has developed during the past decades in the area of medical oncology directly involved in the study of the psychological aspects of cancer. In this study the authors focused in particular on the psychopathological complications of dermatological cancer, the discovery of a possible history of psychiatric disorders prior to the diagnosis of the tumour, the predictive value of the latter concerning further psychiatric complications during cancer, and lastly the possible correlations between stress and the onset of cancer and between religious belief and adaptive strategies. A total of 30 patients suffering from dermatological neoplasia were examined within the setting of a Psychiatric Liaison Service. HDRS and STAI X-1 and 2 were used as psychodiagnostic aids to evaluate the level of depression and anxiety, together with an interview for the clinical evaluation of the patient ad possible life events of particular importance. It was found that 10% of patients conformed to the criteria for the diagnosis of dysthymia and 10% for adaption disorders, and that there was also a high rate of pathological values for status anxiety (66%). These results show that this type of disease is particularly subject to risk for psychiatric complications.     

Sonographic detection of pneumoperitoneum: an experimental and clinical study

The sonographic appearance of intraperitoneal air collection has been studied in 46 patients. In 30 patients (group I), a pneumoperitoneum had been iatrogenically induced either during aspiration of ascitic fluid or during laparoscopy. Three normal volunteers (group II) had been subjected to graded intraperitoneal air injection to quantify the smallest amount of air detectable by ultrasound (US). In eight patients (group III) the sonographic demonstration of free intraperitoneal air led to a diagnosis of hollow visceral perforation; whereas in another five patients (group IV) the sonographic findings reinforced the clinical suspicion of a 'sealed off' perforation in the presence of negative roentgenograms. In all patients intraperitoneal air was seen as an echogenic line with a posterior reverberation or ring down artefact. In patients with free air, this was best seen in the perihepatic spaces with the patient in the supine, left lateral decubitus or prone position. As little as 5 mL of air could be consistently detected in all three volunteers (group II). Artefacts leading to a pseudopneumoperitoneum on US included; (i) the artefacts distal to an overlying rib; (ii) ring-down artefact from air in the adjacent lungs; and (iii) hepatodiaphragmatic interposition of colon. With proper sonographic technique and principles of interpretation these can be distinguished from true intraperitoneal air. Although sonography may be more informative than conventional radiology in patients with hollow visceral perforation, we did not find it more sensitive than conventional roentgenograms in detecting free intraperitoneal air. Sonography, however, is distinctly superior in patients with a sealed off perforation in whom conventional roentgenograms are frequently negative.     

Osteopenia after gastrectomy, fundectomy or antrectomy: an experimental study in the rat

BACKGROUND: Gastrectomy induces osteopenia. In this study, we tested if resection of defined parts of the stomach could reproduce the gastrectomy-evoked osteopenia. METHODS: Rats were subjected to gastrectomy (surgical removal of the glandular part of the stomach), fundectomy (extirpation of the acid-producing part, fundus) or antrectomy (extirpation of the gastrin-producing part, antrum). Calvariae, tibiae and femurs were examined at various times after the operations. The calvariae were subjected to transillumination. Calvariae and tibiae were sectioned and analysed by histomorphometry, tibia sections by the aid of a Merz grid and calvaria sections using computer-assisted image analysis. The intact femurs were subjected to computerized microtomography. RESULTS: Gastrectomy (hypogastrinemia) and fundectomy (hypergastrinemia) resulted in osteopenia, while antrectomy (hypogastrinemia) had less effect on bone. Gastrectomy/fundectomy were associated with loss of trabecules in the tibia and with reduced bone volume in both tibia and calvaria. In contrast, there was only little reduction of cortical bone in the femur. CONCLUSION: Gastrectomy-evoked osteopenia can be reproduced by selective resection of the acid-producing part of the rat stomach (i.e. fundectomy). Antrectomy was less effective. In the long bones, the osteopenia was manifested primarily in trabecular bone and less in cortical bone. The calvaria displayed marked osteopenia. Although the findings indicate that the stomach, notably the acid-producing (oxyntic) mucosa, is important for bone metabolism, the precise mechanisms behind the gastrectomy/fundectomy-evoked osteopenia remain unidentified. Clearly, lack of gastrin is not responsible. The oxyntic mucosa is rich in peptide hormone-producing cells (the so-called ECL cells), with unidentified physiological significance. The ECL cells, which operate under the control of gastrin, have been put forward as a possible source of an osteotropic hormone.     

Epidemiological study of Campylobacter spp. in broilers: source, time of colonization, and prevalence

From October 1993 to August 1994, broiler chickens in four grow-out houses, two previously used (houses 1 and 2) and two newly constructed (houses 3 and 4), were used in a study to determine the source, time of infection, and prevalence of Campylobacter spp. Cecal droppings and cecal samples were obtained from the broilers. Samples were also obtained from water, feed, litter, soil, fans, and workers' boots. Samples were obtained from domestic animals and wildlife species (rectal swabs), including insects, on or near the premises. Broilers in houses 2, 3, and 4 became infected in the second or third week and were fully colonized by day 42. Campylobacter appeared in house 1 during week 2 in a low percentage of the birds, disappearing by the fourth week. Isolates were also recovered from domestic pigs and water on this farm. In house 3, the organism was isolated from workers' boots and a wild bird prior to isolation from the broilers. Following isolation from cecal droppings, the organism was isolated from water, feed, litter, feathers, flies, cattle, feces, and wild animals. In house 2, Campylobacter was isolated from cattle feces and wild birds prior to week 5, when the broilers first became infected, and thereafter from water, feed, insect, and wildlife, and cecal droppings. It was subsequently isolated from workers' boots, cattle feces, feathers, insects, and other wildlife. All ceca taken from 20 birds each from houses 2 and 3 were positive at time of slaughter (day 49). All ceca from house 1 were negative. No ceca were collected from birds originating in house 4. No specific source could be identified from the samples obtained, although apparently the organism permeates the environment and several potential sources are discussed in this paper.     

Entry of Listeria monocytogenes into neurons occurs by cell-to-cell spread: an in vitro study

Listeria monocytogenes is an intracellular pathogen that causes severe central nervous system infection in humans and animals. The ability of this bacterium to penetrate nerve cells was investigated by using rat spinal cell cultures. Entry into distinct cell types, i. e., glial cells and neurons, was monitored by a differential immunofluorescence technique with antibodies against cell type-specific markers and the bacterial pathogen. L. monocytogenes was detected predominantly within macrophages constituting the microglia. Astrocytes and oligodendrocytes, the major components of macroglia, were infected to a lesser extent. Surprisingly, Listeria innocua, a noninvasive and nonpathogenic species, also has the capacity to enter into these three types of glial cells. Entry into neurons was a very rare event. In contrast, we found that L. monocytogenes could efficiently invade neurons when these latter cells were cocultivated with Listeria-infected mouse macrophages. In this case, infection of neurons occurs by cell-to-cell spread via an actA-dependent mechanism. These data support the notion that infected phagocytes can be vectors by which L. monocytogenes gains access to privileged niches such as the central nervous system.     

Bladder substitutes, bile acids and the risk of colorectal cancer: an experimental study

There is a large body of evidence relating the causation of colon cancer to bile acids. Using an animal model, we attempted to address the question, i.e., the incidences of carcinogenesis in the colon as consequences of resection of different bowel segments, predominantly employed in the construction of various forms of intestinal bladder substitutes. 60 male Wistar rats were operated. Group 1 served as control, in group 2, 20 cm of terminal ileum was resected, and rats in group 3 underwent resection of the distal 10 cm of the ileum and 7 cm of the proximal colon. All rats were killed 6 months after surgery and the colon was removed. After examination under 40-fold magnification, in the absence of tumors, 3 biopsies were performed at predetermined positions and underwent histological processing. Even if no tumor was found it would be incorrect to conclude that these results would have an appeasing relevance. The complex and highly different fecal bile acid profiles of the rat compared to man makes it impossible in this context to draw analogies between the rat model and human colonic carcinogenesis. Furthermore, 6 months of observation in the rat might be too short for 'spontaneous' colonic carcinogenesis. Nevertheless, there exists evidence from epidemiological studies to implicate bile acids as an etiological factor in the development and growth of colorectal cancer. Therefore, the importance of colorectal cancer in urologic surgery patients must be kept in perspective. In this direction, further studies are required besides the application of known appropriate preventive measures.     

Stair-step artifacts in three-dimensional helical CT: an experimental study

We describe 3 sibs, their father, and paternal grandfather with amelogenesis imperfecta. In 2 sibs and the father the defect is associated with a neurological syndrome which has a wide range of phenotypic variability. The proposita has ataxia, EEG abnormalities, moderate dementia, and enamel hypoplasia. This case and the affected relatives are discussed in relation to Kohlschütter-T?nz syndrome and neuroectodermal diseases. The syndrome described here, characterized by the association of a genetic enamel defect and neurological impairment, may be of considerable interest in advancing genetic and clinical knowledge on ectodermal tissues and their development.     

Anuran postnasal wall homology: an experimental extirpation study

The nasal placode was extirpated unilaterally in Gosner stage 18-20 embryos of Rana sylvatica, R. palustris and R. pipiens, in order to test alternative proposed schemes of homology for the ethmoidal attachment of the palatoquadrate in anurans and urodeles. Absence of the nasal sac has no pronounced effect on the formation of larval chondrocranial structures. In contrast, in metamorphosed animals the lamina orbitonasalis and inferior prenasal process are the only nasal capsule structures present on the operated side. The medial nasal branch of the deep ophthalmic nerve passes forward over the dorsal surface of the lamina orbitonasalis, rather than through an orbitonasal foramen. Comparison with previous experimental work on urodeles supports the traditional homology of the anuran lamina orbitonasalis with the antorbital process of urodeles and other vertebrates.     

L-DOPA effects on sexual behaviour: an experimental study

Five patients underwent operative repair of an aneurysm of the sinus of Valsalva. Four of the aneurysms were considered as congenital and one as mycotic. There were four males and one female. One patient with VSD and characteristics of Marfan's syndrome die on the first postoperative day of a recurrence of fistulae. The follow-up time is over one year for all but one of the surviving patients. There are no late deaths, and all patients are doing well. Aneurysms and fistulae of the sinus of Valsalva, which are perhaps not as rare as was previously thought, present a challenging surgical problem. Ruptured aneurysms and fistulae, even if asymptomatic, should be treated operatively, preferably by a transaortic approach.     

Hydroxyapatite coated external fixation pins: an experimental study

A sheep model was developed for the implantation of 84 bicylindrical stainless steel external fixation pins. One-half of the pins were coated with hydroxyapatite, and the rest remained uncoated. A set of 6 pins with the same coating was implanted in the lateral side of the left tibias of 14 sheep, the final insertion torque was measured, and a monolateral external fixator was assembled on the pins. The medial tibial middiaphysis then was exposed and a 5-mm resection osteotomy was done. Sheep were euthanized 6 weeks after surgery, radiographs were taken, and the initial extraction torque was measured on 4 pins from each sheep. Undecalcified sectioning and histologic and histomorphometric analyses were done on the remaining 2 pins. Radiographic pin tract rarefaction was significantly lower in the hydroxyapatite coated pins compared with the uncoated pins. Group average insertion torque was 960 +/- 959 Nmm in the hydroxyapatite coated pins and 709 +/- 585 Nmm in the uncoated pins. Group average initial extraction torque was 1485 +/- 1308 Nmm and 298 +/- 373 Nmm, respectively. Bone pin contact was 85.7% +/- 8.9% and 50.3% +/- 20.4%, respectively, in hydroxyapatite coated and uncoated pins. Bone between the threads was 95.6% +/- 5.7% and 80% +/- 8.7%, respectively, in hydroxyapatite coated and uncoated pins. Hydroxyapatite coating was effective for improving the bone-to-pin interface.     

Compartment syndrome after intraosseous infusion: an experimental study in dogs

An experimental study was designed to investigate the development of compartment syndrome with the use of an intraosseous line in dogs. We used an open technique for insertion of a 20-gauge spinal needle to the tibia. The needle was secured to the tibia with bone cement. Throughout the intraosseous infusion of saline with radio-opaque dye (rate, 480 mL/h), serial radiographic examination and pressure monitoring of the anterolateral compartment of the leg was performed. Although there was no change up to approximately 350 mL of fluid infusion, the radio-opaque dye was detected in the soft tissues and compartment pressure increased to more than 35 mm Hg. Compartment pressure continued to increase in direct proportion to the amount of dye infused. In the present study, the possible technical errors, which may cause compartment syndrome, have been eliminated. However, compartment syndrome developed because of the failure of microvasculature within a muscle adjacent to bone. We suggest that there is a need for a dose-and time-dependent scale for safe intraosseous infusion.     

Continuous positive airway pressure and gastroesophageal reflux: an experimental study

Gastroesophageal reflux (GER) often occurs in babies receiving respiratory assistance for neonatal distress. The authors examined the lower esophageal sphincter and the thoracic and abdominal pressure conditions in rats under progressively higher continuous positive airway pressure (CPAP) to test the efficacy of the antireflux barrier under such conditions. Intrathoracic and intraabdominal pressures were recorded within the esophagus and within the inferior vena cava in 10 anaesthesized 250-g male rats. Pull-through techniques were used for lower esophageal sphincter pressure (LESP) and length (LESL) studies, and the length of the intraabdominal segment of the esophagus (LIASE) was also determined. Measurements were performed in baseline conditions and at CPAP levels of 0, 1, 3, 5, and 7 cm H2O. The respiratory effort progressively increased with prolonged expiration and decreased frequency. LESP and LESL did not change significantly, but the antireflux barrier was weakened by a progressive shortening of LIASE. Successive CPAP increases led to increasingly negative thoracic pressures during inspiration, and increasingly positive abdominal pressures during expiration yielded progressively greater transdiaphragmatic pressure gradients. The authors suggest that CPAP weakens the antireflux barrier and, at the same time, increases the gastroesophageal pressure gradient, thus increasing the risk of GER. Although transpolation of experimental data to the clinical setting is always hazardous, the authors believe this issue should be investigated in infants.     

Morphology and function of preserved microvascular arterial grafts: an experimental study in rats

The aim of this study is to examine the morphology and function and small-caliber, arterial grafts after preservation in the University of Wisconsin solution (UW). Rat carotid arteries were stored in UW (n = 10) or in phosphate-buffered saline (PBS) (n = 10) for 1, 3, 7, and 14 days and were examined with light microscopy (LM) and scanning electron microscopy (SEM). Rat aortic preparations were stored in UW or PBS for 1 hour, 24 hours, 72 hours, 7 days, and 14 days and assessed for functional responses (stimulated contraction and endothelium-dependent relaxation). Segments (5 mm) of rat carotid arteries were stored in UW or PBS for 3 days, 7 days, and 14 days and orthotopically implanted as autografts and allografts. No immunosuppressive or anticoagulant agents were used. After 28 days of implantation, the grafts were assessed for patency and excised for LM and SEM. In UW, the endothelial layer remained intact up to 9 days of storage. In PBS, the endothelial layer showed deterioration after 1 day and was completely lost after 3 days. Functional responses were demonstrated to exist for as long as 7 days storage in UW. In PBS, no responses could be evoked after 24 hours storage. Autografts preserved in UW for 3 days (n = 6), 7 days (n = 6), and 14 days (n = 6) showed patency rates of 83.3%, 66.6%, and 66.6%, respectively, whereas patency rates of allografts were 66.6%, 33.3%, and 33.3%, respectively. Autografts stored in PBS for 3 days (n = 6), 7 days (n = 6), and 14 days (n = 6) showed patency rates of 33.3%, 33.3%, and 50%, respectively, whereas patency rates of allografts were 16.7%, 0%, and 33.3%, respectively. The UW preserved autografts showed normal morphology. All other groups showed vessel wall degeneration which in the allograft groups, were accompanied by lymphocellular infiltration. In conclusion, the endothelial layer and vessel wall of arteries are adequately preserved in UW. Functional responses are retained up to 14 days storage in UW, but, are lost after 24 hours storage in PBS. Autograft implantation studies accordingly show good performance of arterial segments preserved in UW, whereas allografts are subject to degradation as a result of rejection.