Search PubMed⌕ Search

Biomedical subjects

S Said

Publications and source records attributed to S Said.

At least 19 recordsLinked to original sources
PubMed2001

[Endoscopic aortofemoral bypass reconstruction: experimental and clinical results].

According to the present experiences, the new videoendoscopic vascular instrument systems have fulfilled the basic requirements for performing videoendoscopic aortoiliac surgery. The animal studies (n = 25) showed clearly, that the piglet is a reproducible and favourable model to acquire the basic surgical techniques for videoendoscopic aortoiliac surgery, since its retroperitoneal anatomy is similar to that of humans. The transabdominal-retroperitoneal approach on human cadavers (n = 6) was soon abandoned, since particularly in obese cases it caused burdensome sliding of the intestine into the operative field adjacent to the renal vessels. The intensive investigations on human cadavers (n = 20) has meanwhile allowed us to constantly expose the aorta above the inferior mesenteric artery up to the left renal vessels without the need to sacrifice the inferior mesenteric artery (total operating time: 3-4.5 hours, aortic reconstruction averagely 42 minutes). The prolonged operating time during the extraperitoneal approach, especially in case of accidental tearing of the retroperitoneum has led us to evaluate the transabdominal paracolic approach (n = 6). This procedure with right-sided positioning of the patient offers a broad operating area and retains the intestine in the right side of the abdomen throughout, thus reducing the operating time in our initial 6 cases to a mean of 2.9 hours (range: 2.5-3.5 hours). As to our limited clinical experience and in accordance to other surgical groups the video assisted aortoiliac surgery (n = 12) by performing a small abdominal incision for the aortic anastomosis under direct vision seems to be an alternative procedure to the total videoendoscopic aortoiliac surgery (n = 7). Further experimental research, consistent development and refinement of videoendoscopic vascular instruments and prospective evaluation of the different videoendoscopic approaches to the aortoiliac vessels are necessary to evaluate the use of the videoendoscopic surgical technique, to clarify its advantages and to probably generalize the procedure in the near future.

Aged↗
PubMed2000

Reverse remodeling of cardiac myocyte hypertrophy in hypertension and failure by targeting of the renin-angiotensin system.

BACKGROUND: ACE inhibitors (ACEIs) and angiotensin II type 1 (AT(1)) receptor blockers are effective in reducing left ventricular mass in hypertension and heart failure. However, the ability of these drugs to reverse excessive myocyte lengthening and transverse growth in heart failure is unknown. METHODS AND RESULTS: L-158,809 (an AT(1) blocker; AT(1)), enalapril (an ACEI), and hydralazine (a vasodilator) were administered to spontaneously hypertensive heart failure rats between 6 and 10 months of age (early treatment) and between 18 and 22 months of age (late treatment). After 4 months of treatment, hemodynamics and chamber dimensions were collected before left ventricular myocyte isolation and subsequent analysis of myocyte shape. Each drug reduced systolic blood pressures to normal values. In the early and late studies, the ACEI reduced myocyte volume. Myocyte length was also reduced in the late study. However, the AT(1) was most effective in reversing myocyte dimensions to near-normal values in both studies. Hydralazine was ineffective in reducing cell size but arrested progression of myocyte lengthening in the late study. Changes in myocyte shape reflected alterations in chamber dimensions and wall thickness. CONCLUSIONS: Reversal of myocyte hypertrophy was produced in hypertensive/heart failure rats with an AT(1). The ACEI was effective but to a lesser extent. Results indicate that it is possible to significantly reverse myocyte remodeling pharmacologically even if therapy is initiated near the onset of failure. Further work is needed to determine whether similar results can be obtained in humans.

Angiotensin II↗
PubMed2000

Sequential synthesis and secretion of pectinases by Penicillium frequentans.

Penicillium frequentans synthesized eleven polygalacturonases and three pectinesterases when grown in the presence of pectin, sodium polypectate or monogalacturonic acid. When glucose was the sole carbohydrate source in the medium two of these polygalacturonases and one pectinesterase were produced. The enzymes produced under any of these conditions degraded pectic substrates to monogalacturonic acid, suggesting that this monosaccharide or its metabolites should induce the pectinolytic complex. All pectinesterases and most of the extracellular polygalacturonases were synthesized after the 2nd hour of incubation. The pectinases produced by Penicillium frequentans were not secreted at the same time but after 5 hours of incubation all of them could be detected outside the cell those detected only inside the cell were probably membrane-associated or unglycosylated forms of the extracellular pectinases.

Carbon↗
PubMed2000

Is apoptosis present in progression to chronic hypertensive heart failure?

BACKGROUND: Cardiomyocyte apoptosis is believed to occur in hypertension. Isolated myocyte data from spontaneously hypertensive heart failure (SHHF) rats, however, suggest that significant myocyte loss does not occur in this model. To investigate this issue further, heart sections from failing and nonfailing SHHF rats were examined by using in situ terminal deoxynucleotidyltransferase-mediated 2'-deoxyuridine 5'-triphosphate nick end-labeling (TUNEL). Additional hearts were optimally fixed by perfusion with glutaraldehyde and histologically examined for evidence of myocyte damage or loss. METHODS AND RESULTS: Five Sprague-Dawley (SD) rats, 8 failing SHHF rats, and 6 nonfailing SHHF rats were perfusion-fixed with formaldehyde and used for TUNEL assay. Heart sections from each group were also treated with DNase for positive controls. There were no significant differences in the number of TUNEL-positive cells in SD, failing SHHF, and nonfailing SHHF rats. Additionally, extensive screening of 1-microm sections of optimally fixed failing hearts revealed little evidence of myocyte loss or nuclear characteristics suggestive of apoptosis. CONCLUSION: Apoptosis does not appear to be an important component of myocardial remodeling in SHHF rats during hypertrophy or end-stage heart failure. Examination of myocyte nuclear structure by high-resolution microscopy of optimally fixed tissues is recommended as an alternative approach to study apoptosis.

Animals↗
PubMed2000

Specificity of TUNEL method depends on duration of fixation.

Recent evidence has suggested that apoptosis plays an important role in various diseases, but concerns about the specificity of the TUNEL method for detecting apoptosis have been raised. The purpose of the present study was to investigate the specificity of the TUNEL method by using immersion and perfusion fixed tissues from both normal rats and rats with heart failure. Although a few positive cells were observed in perfusion fixed tissues, a significant number of positive cells were observed in immersion fixed tissues, especially when fixed tissues were kept for an extended time before the TUNEL assay was applied. The results of TUNEL staining should be interpreted with caution. When immersion fixation is used, fixed tissues should be assayed by the TUNEL method before the DNA degenerates.

Animals↗
PubMed2000

[Renal osteodystrophy (1): invasive and non-invasive diagnosis of its pathologic varieties].

1. Renal osteodystrophy is a general term encompassing all the disturbances of the phosphocalcic metabolism and their associated bone and soft tissue abnormalities, which progressively occur in chronic renal failure. In this article we detail their main histopathological and etiopathogenic aspects as well as their invasive and non invasive diagnostic approach. 2. Osteitis fibrosa is characterized by extensive medullary fibrosis and osteoclastic hyperresorption linked to PTH hypersecretion. 3. Adynamic bone disease is mainly related to iatrogenic oversuppression of PTH secretion. It is favored by aluminum overload which directly inhibits the osteoblasts. It is characterized by a low bone formation rate without primary mineralization defect so that the osteoid seam thickness is normal or low, in contrast to osteomalacia in which by definition osteoid thickness is increased. 4. Osteomalacia is mainly due to aluminum intoxication, vitamin D insufficiency, hypocalcemia, acidosis and exceptionally to hypophosphatemia. 5. The differential diagnosis between the histopathological entities may be oriented on clinical, radiological and biochemical means. Only the bone biopsy can make the diagnosis with certainty. This latter is however necessary for appropriate treatment only in the patients who have been exposed to aluminum and who are symptomatic or hypercalcemic in order to distinguish severe osteitis fibrosa from aluminic bone disease, and more particularly from mixed osteopathy. Indeed surgical parathyroidectomy in patients with mixed osteopathy associating bone hyperremodeling and mineralization defect with inappropriately thick osteoid seam may induce fracturing low turn over aluminic bone disease.

Bone and Bones↗
PubMed2000

[Renal osteodystrophy (3); its treatment in dialysis patients].

The prevalence and the clinical gravity of the various histopathological varieties of renal osteodystrophy in dialysis patients depends on the severity of both the aluminium intoxication and that of hyperparathyroidism. The prevalence of bone pains, fractures and hypercalcemias are the highest in adynamic bone diseases (ABD) with severe aluminium intoxication, then in osteitis fibrosa and mixed osteopathy, in the ABD with moderate aluminium intoxication and rare in the mild lesion in spite of similar moderate aluminium intoxication. In the absence of aluminium intoxication, hypercalcemia and hyperphosphatemia prevalence is higher only when intact PTH is more that 4 times the upper limit of normal. When PTH is between 1 and 2 folds the ULN this prevalence is null and bone mineral density is the highest. 2. The low turnover aluminic bone diseases (osteomalacic or adynamic) will be cured by long term deferoxamine treatment. The hazards of such treatment justify the performance of a bone biopsy to ensure the diagnosis. Their prevention relies on adequate treatment of tapwater and definitive exclusion of long term administration of aluminum phosphate binders. 3. Non aluminic osteomalacia will be treated according to the same guidelines given for the uremic patients before dialysis. 4. Non aluminic adynamic bone disease will be cured by means aiming at stimulating PTH secretion as discontinuing 1 alpha hydroxylated vitamin D derivatives, and, if there is no hyperphosphatemia by discontinuation of calcium supplement. In case of hyperphosphatemia in dialysis patients CaCO3 doses have to be nevertheless increased after the dialysate calcium concentration (DCa) has been decreased in order to induce a negative perdialytic calcium balance for PTH secretion stimulation. In the near future substitution of CaCO3 by non calcemic non aluminic phosphate binders will suffice. 5. Osteitis fibrosa due to hyperparathyroidism will be treated first by securing an optimal vitamin D repletion (bringing plasma 25OH vitamin D around 30 and 60 ng/ml or 75-150 nmol/l) and by correcting hypocalcemia and hyperphosphatemia by CaCO3 at high doses (3-12 g/day) taken with the meals. In case of hypercalcemia dialysate calcium concentration will be decreased to correct it or, in a near future, CaCO3 will be decreased to 3 g/day and hyperphosphatemia will be controlled by non calcemic, non aluminic phosphate binders. When hyperphosphatemia is controlled whereas plasma calcium is normal or low, 1 alpha hydroxylated vitamin D derivatives can be administered. 6. Instrumental parathyroidectomy should be considered when plasma levels of intact PTH remain above 7 folds the upper limit of normal whereas hyperphosphatemia persists and hypercalcemia occurs in order to prevent thining of the corticals and subsequent fracture risk. In case of previous exposition to aluminum, a deferoxamine test and/or a bone biopsy will be performed to decide a long term DFO treatment before the parathyroidectomy in order to prevent the transformation of a mixed osteopathy into an aluminic adynamic bone disease. 7. The difficulty of hyperparathyroidism control in dialysis patients is due to poor compliance to phosphate binders and to irreversible parathyroid hyperplasia with occured before the dialysis stage. This stress the primary importance if its early prevention without iatrogenia by first CaCO3 and vitamin D repletion, as soon as the creatinine clearance decreases below 60 ml/min/1.73 m2.

Aluminum↗
PubMed1999

Lumbosacral anterolateral spinal arteries and brief review of "accessory" longitudinal arteries of the spinal cord.

The lumbosacral anterolateral spinal arteries (LALSA) were studied in 14 injected lumbosacral spinal cords. Contrary to many previously published opinions, which claimed that virtually all of the formerly described "accessory" longitudinal arteries of the vasa corona, were too inconstant to be of significance, the LALSA in this series were reliably present bilaterally and averaged a length of 8.4 cm. They ran in the acute angles formed by the emergence of the fascicles of the lumbosacral anterior spinal nerve roots and in this position, served as the origin for most of the proximal radicular arteries that supply the cranial half of the motor roots of the cauda equina. A review of the literature and analysis of other accessory longitudinal spinal arteries revealed that two other pairs of accessory spinal vessels, the lateral cervical spinal arteries (LCSA) and the lateral spinal arterial axes (LSA), have a demonstrable functional role and were sufficiently constant, along with the LALSA, to warrant inclusion in detailed descriptions of human spinal cord vasculature.

Cadaver↗
PubMed1999

Laparoscopic aortofemoral bypass grafting: human cadaveric and initial clinical experiences.

PURPOSE: Postoperative complications are mainly related to the surgical trauma derived from the extensive abdominal incision and dissection after a conventional aortofemoral bypass grafting procedure. In an attempt to reduce postoperative complications, a concept of video-endoscopic vascular surgery on the infrarenal aortoiliac artery has been developed. On the basis of our experience with the practicability of video-endoscopic vascular surgery in the pelvic region in an animal study and in a pilot study of human cadavers, the purpose of this report was to describe three different methods that we evaluated on human cadavers and that we partly applied to patients. METHODS: In this experimental study, three different approaches were used to perform video-endoscopic aortofemoral bypass grafting. We performed an observational trial on human corpses (n = 24) with the transabdominal-retroperitoneal approach (TARA), the extraperitoneal approach (EPA), and the transabdominal left paracolic approach (TAPA). The EPA also was applied to patients with aortoiliac occlusive diseases. RESULTS: The TARA on cadavers (n = 4) soon was abandoned because it caused a burdensome sliding of the intestine into the operative field adjacent to the renal vessels, particularly in cases with obese subjects. In comparison, the TAPA (n = 6) with right-sided positioning of the patient retained the intestine in the right upper abdomen throughout the procedure. Until a surgeon actually is acquainted with the anatomic landmarks and the laparoscopic preparation technique, the EPA (n = 14) is a challenging procedure that necessitates thorough training. As with the TAPA, the EPA represents a procedure that reveals constant exposure of the operating field, even in cases with obese subjects. In the clinical observational study (n = 7), aortobifemoral bypass grafting was achieved totally laparoscopically with the EPA. The mean operating time was 6.5 hours and ranged from 3 to 10 hours. Blood transfusions were necessary after surgery in three patients (range, 1 to 3 red packed blood cells). One patient, who had had occlusion of the inferior mesenteric artery, died of ischemic colitis at postoperative day 10. The other patients had uneventful postoperative courses with minor wound discomfort. CONCLUSION: Laparoscopic vascular surgery seems to be a promising procedure to minimize postoperative complications. On the basis of our experience, we do not favor the TARA. Because it necessitates steep Trendelenburg positioning to displace intra-abdominal organs, the TARA is not an appropriate approach, particularly in obese and cardiopulmonary frail cases. Contrarily, the TAPA and the EPA deliver potentially better results in terms of exposing the operative field and thus reducing operating time and perioperative morbidity rates. A prospective cadaveric and clinical trial may be justified to further evaluate the use of these surgical techniques.

Aged↗
PubMed1999

DNA stability and thiol-disulphide status of rat sperm nuclei during epididymal maturation and penetration of oocytes.

DNA stability and thiol-disulphide status of rat sperm nuclei was observed in vivo during maturation in the epididymis and penetration of oocytes. When spermatids and spermatozoa were stained with acridine orange after fixation with acetic alcohol, the red/green fluorescence ratio observed under a confocal microscope was not different between spermatids (3.81 +/- 0.16) and testicular spermatozoa (4.03 +/- 0.34), and then decreased sharply (p < 0.01) as the spermatozoa descended the epidymis to the caput epididymis (1.13 +/- 0.03). However, the ratio was not different among corpus (0.69 +/- 0.01), cauda epididymis (0.68 +/- 0.11) and ejaculated spermatozoa (0.63 +/- 0.01). On the other hand, when spermatozoa were labelled with monobromobimane (mBBr), the fluorescence intensities gradually decreased (p < 0.01) during passage of spermatozoa from testis (4.74 +/- 0.16) through epididymis (caput, 2.72 +/- 0.08; corpus, 1.07 +/- 0.03; cauda, -0.05 +/- 0.05; ejaculated, 0.08 +/- 0.03). The acridine orange red/green fluorescence ratio increased (p < 0.01) during zona penetration (binding sperm, 0.52 +/- 0.09; perivitelline sperm, 0.64 +/- 0.16) and sperm decondensation (decondensed sperm, 0.69 +/- 0.12). When spermatozoa in the perivitelline space were labelled with mBBr, the fluorescence was detected. These results demonstrate that DNA stability against acid appears to be ahead of the oxidation of protamine during sperm maturation in the epididymis and is an initial event of the unpackaging process in rat genome occurring during or just after zona penetration but before ooplasm penetration.

Acridine Orange↗
PubMed1999

GCF levels of MMP-3 and MMP-8 following placement of bioresorbable membranes.

Matrix metalloproteinases (MMPs) are responsible for remodeling and degrading extracellular matrix and basement membrane components. MMP-3 and -8 levels were assessed in this study during the early healing phase following a guided tissue regeneration (GTR) procedure. 32 patients, having 2 or 3 walled intrabony defects of PD > or =6 mm, were stratified into 2 groups on the basis of age, sex, smoking status and disease severity. All intrabony defects were treated using the resorbable Guidor membrane but only 1 group of patients was given a pre-operative dosage of antibiotic (3 g amoxycillin). GCF samples for the quantification of MMP-3 and -8 levels were obtained from the intrabony site where a membrane was placed (membrane site), from the non-adjacent site on the adjacent tooth which was involved in the surgical flap (surgical control site), and from a healthy site (healthy) on the contralateral side. The GCF samples taken at baseline, 1 week, 4 weeks and 3 months after surgery were analyzed using an enzyme linked immunoabsorbent essay (ELISA) for MMP-3 and using a time-resolved immunofluorescence assay (IFMA) for MMP-8. MMP-3 was detected in a very low % of sites at baseline while relatively high levels of MMP-8 were detected at all 3 types of sites at baseline. MMP-8 levels increased for all sites at week 1, and this was statistically significant for the membrane site, but at week 4, the levels decreased for both the membrane and the surgical sites. There was no statistically significant difference between the levels of MMP-3 and -8 in the antibiotic and non-antibiotic group. Collagen remodelling occurs during the early wound healing period following surgical and regenerative procedures. The levels of MMP-3 and -8 in GCF appear to reflect these processes. Interestingly, the presence of the membranes appeared to increase the levels of MMP-3 and -8 and may relate to the resorption of the resorbable membrane by host systems.

Absorbable Implants↗
PubMed1999

Gender-related differences in myocyte remodeling in progression to heart failure.

Gender-related differences responsible for the better prognosis of females with heart failure have not been clearly established. To address this issue, we investigated potential gender-related differences in myocyte remodeling in spontaneously hypertensive heart failure rats. Echocardiograms and myocyte growth were compared between males and females at compensated (2, 4, and 6 months) and decompensated (18 months in males and 24 months in females) stages of cardiac hypertrophy. Although left ventricular diastolic dimensions did not differ significantly between failing male and female rats, fractional shortening declined significantly only in failing males. Myocyte cross-sectional area did not change after 4 months of age in both genders, which is likely to be responsible for the absence of a change in left ventricular wall thickness during the progression to heart failure. Myocyte volume and cross-sectional area were significantly larger in males than females at 2, 4, and 6 months of age, although there were no significant differences at the failing stage. Reduced adaptive hypertrophic reserve was observed in males, which is likely to contribute to the higher morbidity and mortality of males with chronic heart failure.

Animals↗
PubMed1999

Comparative study of intracellular and extracellular pectinases produced by Penicillium frequentans.

The filamentous fungus Penicillium frequentans synthesized eleven polygalacturonases (PGs) and two pectinesterases (PEs) when grown in liquid culture supplemented with pectin. Seven PGs and the two PEs were secreted in the medium, whereas four PGs were not secreted. Among the secreted PGs, the endo-PG (band 10) and exo-PGs (band 5) were the enzymes secreted at the highest levels. All secreted PGs bound to lectin and their secretion and/or enzymic activities were inhibited by tunicamycin (TM), except for the constitutive and inducible endo-PG (band 10). Studies on the affinity for concanavalin A (ConA) and the effect of TM suggested that the secreted endo-PG and exo-PG differed in level and process of glycosylation. The exo-PG was characterized as a N-glycoprotein, whereas the endo-PG is probably an O-glycoprotein. The PGs (bands 3 and 4) were neither bound to ConA nor secreted and their enzymic activities were inhibited by TM, suggesting that they are probably N-glycoproteins with complex oligosaccharides of type three and tetra-antennary structure. The other PGs (bands 6 and 8) that were not secreted and did not bind to ConA were not inhibited by TM. These enzymes presented chromatographic characteristics and effects with TM that were similar to endo-PG (band 10), because these PGs might be unglycosylated or/and aggregate forms of the endo-PG (band 10).

Carbohydrates↗
PubMed1999

Giant lipoma of the larynx: a case report and literature review.

Fewer than 15% of lipomas occur in the head and neck. To date, fewer than 100 cases of laryngeal lipoma have been reported in the literature. Typical clinical manifestations include dysphagia, dyspnea and hoarseness, as well as the presence of a smooth or pedunculated mass seen endoscopically and a low attenuation mass on computed tomography scan. Pathologic sections commonly reveal a tumor consisting of mature adipocytes, which is often encapsulated. Treatment of laryngeal lipoma varies from conservative total endoscopic removal to external surgical approaches. The following is a report of a single case of laryngeal lipoma, including pathologic and radiologic findings, as well as a review of the literature.

Humans↗
PubMed1999

[Role of the time of administration of calcium carbonate (before or during mealtime) in the control of hyperphosphatemia in patients on maintenance hemodialysis].

UNLABELLED: A study has claimed that at equal elemental calcium dose, CaCO3 was not less but equally efficient in controlling predialysis hyperphosphatemia as calcium acetate provided both calcium salts were given five minutes before the meals instead of during the meals because the higher acidity of a fasting gastric juice would allow a better dissociation of CaCO3. To examine the point that CaCO3 is more efficient if it is taken five minutes before compared to during the meal, we performed a two month randomised cross-over trial in twelve reliable and stable patients maintained on chronic hemodialysis while their treatment and diet remained constant. Comparison of the plasma concentrations measured during the two modes of administration showed no significant difference in creatinine, urea, bicarbonate, intact-PTH. Mean (+/- SD) plasma PO4 was significantly higher (1.93 +/- 0.50 versus 1.72 +/- 0.40 mmol/l; p = 0.02) whereas corrected plasma Ca was significantly lower (2.30 +/- 0.15 versus 2.38 +/- 0.17 mmol/l; p = 0.01) when CaCO3 was given before the meals than during the meals. CONCLUSIONS: a) administration of CaCO3 before the meal decreases its efficiency in controlling hyperphosphatemia since plasma PO4 was actually slightly higher with this timing of administration; b) administration of CaCO3 before the meal is associated with significantly lower plasma corrected calcium suggesting a smaller absorption of calcium which may be an advantage but only in hypercalcemic patients; c) there is no reason other than the prevention of its hypercalcemic effect to recommend the administration of CaCO3 just before the meals than during the meals.

Aged↗