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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies of normal hearts have revealed a variety of intrinsic connective tissue structures that surround and interconnect myocytes and ventricular mural layers. Among these structures, springlike coiled perimysial fibers, arrayed parallel to myocytes in the interstitial space, have been described in papillary muscle and ventricle. To evaluate the role of the coiled perimysial fibers under perturbed conditions, rat ventricles were filled with barium-gelatin under different pressures and fixed, and then the myocardium was impregnated with silver to visualize the connective tissue. Ventricles were filled at 30, 70 and 100 to 120 mm Hg. The coiled perimysial fibers were studied for their orientation, stretch, integrity and relation to sarcomere length. The coils were noted to embed within the fibrous anulus and to knot into an umbilical-like mass at the apex, thus anchoring them at both ends of the ventricle. They underwent focal straightening even at 30 mm Hg, with generalized straightening and disruption at the highest pressure; changes were most pronounced in the midventricle. Sarcomeres were maintained below 2.2 micron at 30 and 70 mm Hg of cavity pressure in regions of coiled perimysial fiber stretch; only with fiber disruption at 100 to 120 mm Hg were sarcomeres significantly lengthened. Other findings included connective tissue disruption between ventricular wall layers that allowed slippage of myocytes and mural thinning. These observations suggest that coiled perimysial fibers may act as a buffer to protect myocytes from damage under the effects of high cavity pressure.
J Am Coll Cardiol 1988 Dec
PMID:The effects of acutely increased ventricular cavity pressure on intrinsic myocardial connective tissue. 319 55

Topographic changes in the completely healed (6 weeks) left ventricle of the rat, caused by early (30 minutes) and delayed (90 minutes) coronary artery reperfusion, were examined. With early reperfusion the extent of the scar, as a percentage of left ventricular (LV) circumference, was reduced compared to the extent of the scar in rats with permanent occlusion (27 +/- 3% vs 42 +/- 2%, p less than 0.01). Early reperfusion also preserved LV topography by preventing dilation of the LV cavity and thinning of the healed free wall. Late reperfusion (90 minutes) did not reduce the extent of the scar (35 +/- 3% vs 42 +/- 2% of LV circumference, p = NS) or prevent dilation of the LV cavity compared with permanent occlusion. However, the healed free wall/noninfarcted septum ratio was significantly greater in rats with late reperfusion than in those with permanent occlusion (0.98 +/- 0.06 vs 0.73 +/- 0.07, p less than 0.05). Thus early reperfusion completely inhibited scar thinning and dilation of the LV cavity, maintaining normal LV topography. Late reperfusion, too late to reduce infarct size, still contributed to improved healing of the myocardium by resulting in a thicker scar.
Am Heart J 1988 Dec
PMID:Left ventricular topographic alterations in the completely healed rat infarct caused by early and late coronary artery reperfusion. 319 35

Sixty-three cases of vascularised lipid keratopathy were treated with the argon laser to occlude feeder vessels which had been identified by fluorescein angiography. There was a reduction in extent in 62% and density in 49%. Visual acuity was improved in 48%. Six patients had keratoplasties shortly after treatment, none of which showed graft rejection. Minor complications included temporary haemorrhage into the cornea and iris atrophy. A more serious problem was severe corneal thinning after resorption of lipid. The patients had to be carefully followed up and maintained on a low dose of topical steroid.
Br J Ophthalmol 1988 Dec
PMID:Argon laser treatment of lipid keratopathy. 322 45

Chronic, rapid ventricular pacing produces congestive heart failure in the dog. Using echocardiography, the features of developing heart failure were analysed and the capacity of this model for recovery was assessed once pacing had been discontinued. Fifteen dogs were studied; nine were paced at 250 beats/min (bpm) to severe heart failure (5.0 +/- 1.8 weeks) and six served as sham controls. In the paced animals at severe heart failure, two-dimensional echocardiography demonstrated a significant increase in diastolic cross-sectional cardiac area (from 11 +/- 3 to 16 +/- 2 cm2, p less than 0.05), associated with a marked fall n area ejection fraction (54 +/- 8 to 21 +/- 8%, p less than 0.05), and significant left ventricular wall thinning (from 6.0 +/- 0.7 to 4.7 +/- 0.9 mm, p less than 0.05). In addition, significant increases in heart rate (77 +/- 7 to 126 +/- 13 bpm, sinus rhythm; p less than 0.05), respiratory rate (41 +/- 13 to 80 +/- 20 cycles/min, p less than 0.05), and body weight (21 +/- 1 to 24 +/- 3 kg, p less than 0.05) were noted. Serum sodium fell (146 +/- 3 to 140 +/- 8 mmol/L, p less than 0.05), while blood urea nitrogen (6 +/- 2 to 10 +/- 2 mmol/L, p less than 0.05) and creatinine (86 +/- 12 to 101 +/- 15 mmol/d, p less than 0.05) increased. Recovery was characterized by rapid improvement such that all measured parameters normalized by 1 week, except for cross-sectional cardiac area which remained dilated up to 4 weeks (14 +/- 3 cm2, p less than 0.05 versus control).(ABSTRACT TRUNCATED AT 250 WORDS)
Can J Physiol Pharmacol 1988 Dec
PMID:Recovery from heart failure: structural and functional analysis in a canine model. 322 85

To determine the serial changes in T1 and T2 relaxation times of myocardial infarction, and their relationship to observed changes in water content, regional myocardial blood flow, and histopathology, rabbits were studied at 14 time intervals ranging from 30 min to 6 months after coronary artery ligation. All values were compared to a control group. Hearts were subdivided into infarct and normal segments for measurement of blood flow, water content, and relaxation times (20-MHz spectrometer); other hearts were excised intact for histopathologic studies. T1 relaxation time of infarcted myocardium did not change significantly compared to control over the 6-month study period. T2 relaxation time increased (P less than 0.0001) at 3 days and returned to baseline by 2 months. Consonant with the increase in T2 of infarct, nuclear magnetic resonance (NMR) images at 3 days demonstrated an increase in signal intensity of infarct compared to surrounding normal myocardium. At 6 months, marked myocardial thinning was observed without changes in signal intensity. Changes in T2 of infarcted myocardium were not related to changes in water content or severity of ischemia, but correlated best with infarct healing and scar formation as detected on histopathology. In conclusion, the findings of this study indicate that T2 relaxation time of the infarcted myocardium increases markedly at 3 days and remains elevated for 2 months. These changes correlate best with the onset and progression of infarct healing. These data demonstrate the potential of T2-weighted NMR imaging for assessing healing patterns following ischemic myocardial injury.
Magn Reson Med 1988 Dec
PMID:Serial changes in nuclear magnetic resonance relaxation times after myocardial infarction in the rabbit: relationship to water content, severity of ischemia, and histopathology over a six-month period. 323 Oct 66

The purpose of the present study was to elucidate the relationship between the oral hygiene at the bridge pontic and the inflammatory changes in the adjacent mucosa. The study consisted of three 4-wk periods with different hygienic measures: 1) no oral hygiene around and beneath the pontic, 2) thorough hygiene using toothbrush and toothpicks and 3) thorough hygiene using a toothbrush and dental floss every day. The amount of accumulated bacterial deposits on the pontic and the inflammation in the pontic area were estimated using quantitative microbiologic tests, and clinical and histologic examinations. When dental floss had been used the mucosa was healthy while it showed mild or moderate inflammation after the other experimental periods. There was a high correlation between the amount of mucosal exudate and the inflammation in the mucosa as measured by a modified Gingival Index. Daily use of dental floss resulted in a significantly lower number of microorganisms per mm2 compared with the other hygienic measures. Histologic sections of the biopsies showed changes in form of parakeratosis with thinning or loss of stratum corneum. The investigations have demonstrated that insufficient oral hygiene is an important factor in the development of inflammatory changes in the oral mucosa beneath bridge pontics. Regular use of dental floss ought to be a part of the oral hygiene regimen in patients wearing fixed bridges.
Scand J Dent Res 1987 Dec
PMID:Influence of oral hygiene on the mucosal conditions beneath bridge pontics. 332 91

Skull lesions known as porotic hyperostosis have been of interest to researchers since the mid-19th century. The etiology of porotic hyperostosis has long been a matter for speculation yet there has never been complete acceptance or substantiation of any one of the many theories proposed. Today the most widely accepted theory suggests that anemias of either acquired or genetic origin are responsible for porotic hyperostosis. The present study tests this hypothesis using criteria which were chosen after the examination of clinical radiographs of patients with various types of anemia. These criteria are: the presence of "hair-on-end" trabeculation, outer table thinning, texture changes, diploic thickening, orbital roof thickening, orbital rim changes, and the underdevelopment of frontal sinuses. A comparison of these criteria from the clinical X-rays with X-rays of skulls with porotic hyperostosis provides a more rigorous, repeatable, and standardized method upon which to base a diagnosis. This approach enables radiography to provide the necessary link between the clinical and anthropological with which to investigate the origin of porotic hyperostosis.
Am J Phys Anthropol 1987 Dec
PMID:A radiographic study of porotic hyperostosis. 332 83

As part of a long-term inhalation toxicity study with acetaldehyde in rats, progression and regression of nasal lesions were studied in animals exposed to 0, 750, 1500 and 3000/1500 ppm of the test compound for 52 weeks and killed after recovery periods of 26 or 52 weeks. Major compound-related nasal lesions found at the end of the exposure period comprised: (a) thinning of the olfactory epithelium with loss of sensory and sustentacular cells at all concentrations; this condition was accompanied by focal basal cell hyperplasia in low- and mid-concentration animals; (b) hyper- and metaplasia of the respiratory epithelium frequently accompanied by keratinisation and occasionally by proliferations of atypical basal cells in the top-concentration group; and (c) rhinitis in several top-concentration rats. There was strong evidence on the one hand that the hyper- and metaplastic changes found in the respiratory epithelium and the basal cell hyperplasia seen in the olfactory epithelium after 52 weeks of exposure may progress to neoplasms despite discontinuation of the treatment. On the other hand these hyper- and metaplastic changes may regress during the recovery period. Regeneration of the olfactory epithelium was evident in several low- and mid-concentration animals, but not in top-concentration rats. The regenerated epithelium was seen as a layer of stratified undifferentiated epithelium containing small nerve bundles, tiny groups of sensory cells, and groups of epithelial cells resembling acinar cells of the glands of Bowman. Furthermore, replacement of olfactory epithelium by respiratory epithelium was a frequent finding. It was concluded that rat olfactory epithelium severely damaged by acetaldehyde may regenerate, most probably from basal cells, provided the olfactory epithelium has not been fully destroyed.
Toxicology 1987 Dec 14
PMID:Inhalation toxicity of acetaldehyde in rats. IV. Progression and regression of nasal lesions after discontinuation of exposure. 342 85

A technique is described for occlusion of bridging vessels associated with retinal breaks, and recurring vitreous hemorrhage. Argon laser photocoagulation, applied around and to the vessel in repeated sessions, produces scarring and progressive thinning of the retina until laser energy absorbed in the deep pigmented layers can reach the vessel and occlude it. Seventeen patients presenting with vitreous hemorrhage from bridging vessels were treated. Vitreous hemorrhage recurred in only two patients, one of whom had not returned for completion of treatment. The authors conclude that repeated argon laser photocoagulation is a safe, simple, and effective method for preventing recurrent vitreous hemorrhage from bridging vessels.
Ophthalmology 1987 Dec
PMID:Occlusion of bridging or avulsed retinal vessels by repeated photocoagulation. 343 31

Desoxycorticosterone acetate (DOCA) was injected intramuscularly to pregnant rats at the III, or II-III trimester of pregnancy. By the end of pregnancy with increasing body mass of the female rats, the hormonal dosage dropped. The newborn rat skin was studied. The prenatal effect of DOCA resulted in thinning the epidermis, the decreasing dosage in certain activation of the epithelial proliferative activity and in appearance of foci of its hyperplasia. The hormone in the dose 0.8-1.0 mcg/100 g of the body mass activates the proliferative ability of fibroblasts, elevates the quantity of tissue basophils, increases secretory activity of both of them; this produces thickening of the derm. In the microvessels morphofunctional activity of endothelium increases, in the basal membrane contents of PAS-positive substances drop, the wall is often infiltrated with lymphocytes. Correlations between the cells and other structural components of the skin intensify. When the dose of DOCA increases and the time of the injection is short, the proliferative and secretory activity of fibroblasts is inhibited, but morphofunctional properties of the tissue basophils are stimulated. Congestive phenomena develop in the microvessels, mitotic activity of endotheliocytes is inhibited, in the basal membrane amount of the PAS-positive substances sharply decreases, perivascular edema develops in the connective tissue. Weakening or imbalance of the correlations is observed.
Arkh Anat Gistol Embriol 1987 Dec
PMID:[Morphofunctional characteristics of the skin of newborn rat pups with prenatal exposure to desoxycorticosterone acetate]. 344 51


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