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Biomedical subjects

S Said

Publications and source records attributed to S Said.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Inhibition of gastric secretion by omeprazole and efficacy of calcium carbonate in the control of hyperphosphatemia in patients on maintenance hemodialysis].

UNLABELLED: Apparent contradictions exist in the literature regarding the effect of gastric secretion inhibition on phosphatemia. In healthy adults, omeprazole has been reported to prevent the increase of plasma phosphate or of phosphaturia observed after an acute phosphate load suggesting an inhibition of phosphate absorption. In patients on chronic hemodialysis their hyperphosphatemia is associated to gastric hypersecretion but the inhibition of this latter by ranitidine in patients taking CaCO3 has been reported to increase their plasma phosphate. Because of this contradiction, we have made an open cross-over study in 16 stable and compliant patients in chronic hemodialysis taking a mean daily dose of 9.4 +/- 4 g of CaCO3 and compared their predialysis plasma concentration of phosphate, calcium, protides, bicarbonates, intact PTH, urea and creatine for two successive periods of two months without or with 20 mg of omeprazole. Plasma phosphate did not increased significantly with omeprazole (from 1.80 +/- 0.38 to 1.89 +/- 0.42 mmol/l) whereas plasma corrected calcium significantly decreased from 2.41 +/- 0.18 to 2.36 +/- 0.16 mmol/l (p = 0.04) and plasma bicarbonate decreased significantly from 26.7 +/- 3.5 to 25.7 +/- 3.1 mmol/l (p < 0.05). No significant change was observed in plasma creatine and urea suggesting stability of dialysis efficiency and of protein and therefore phosphate intake. CONCLUSION: These data do not support that CaCO3 efficiency as phosphate binder is decreased with inhibition of the gastric secretion by omeprazole.

Adult↗
PubMed1999

Studies of pectic enzymes produced by Talaromyces flavus in submerged and solid substrate cultures.

Tons of peel and rag are generated each year by industries of citrus fruit juices. These by-products are used either for the elaboration of pectin or as substrate for enzyme production. Talaromyces flavus produces extracellular pectinesterase and polygalacturonase after 24 h in submerged culture supplemented with 0.5-0.8% citrus pectin preceded by preculture for 24 h in 2% (w/v) sucrose or in solid substrate culture on passion fruit peel, lemon or orange pulp pellets after 3-6 days of incubation. Chromatographic profiles in a CM-Sepharose column of liquid and solid cultures were very similar, consisting of one endopoligalacturonase (endo-PG I) and one pectinolytic complex constituted by an endopoligalacturonase (endo-PG II) and pectinesterase. Pectin and pectate lyases were undetectable in both media. In Talaromyces flavus the synthesis of pectinases was repressed by glucose and finally controlled by the concentration of products from pectic enzymes degradation.

Ascomycota↗
PubMed1998

Correlation of myocyte lengthening to chamber dilation in the spontaneously hypertensive heart failure (SHHF) rat.

Chronic congestive heart failure of various etiologies is characterized by progressive chamber dilation. Although myocyte lengthening is involved, it is not known if this cellular change can account for all of the chamber dilation. The controversy is due largely to technical limitations in collecting data on chamber circumference, myocyte length, and sarcomere length simultaneously. To address this issue, the contributions of myocyte and sarcomere lengthening to progressive chamber dilation in spontaneously hypertensive heart failure (SHHF) rats was examined using a new approach. Female SHHF rats (n=31) were examined at various time points between 2 months of age and the onset of end-stage heart failure (18 months or older). A new method enabled simultaneous collection of data on myocyte length, sarcomere length, and chamber circumference using formalin-fixed tissue. Reliability of cellular measurements was confirmed with an alternate method. LV myocyte length increased linearly between 2 and 24 months of age due to series addition of sarcomeres. Myocyte length increased in direct proportion to chamber circumference during this period (r=0.93, P<0.001). Results suggest that myocyte lengthening alone can account for chamber dilation in the progression to heart failure. Excessive myocyte lengthening is a slow, progressive change that begins long before clinical signs and symptoms of heart failure appear in this model of hypertension and failure. Since myocyte remodeling in hypertensive humans with and without failure is known to resemble that in SHHF rats, these data should provide important insight into chamber dilation and the progression of heart failure in humans.

Animals↗
PubMed1998

Congenital and Atherosclerotic (Acquired) Coronary Artery Aneurysms: Coronary Angiographic and Morphologic Observations in 10 Patients

Coronary angiographic observations in 10 patients with coronary artery aneurysms (CAAs) are reported. Four patients had atherosclerotic (acquired) and six had congenital CAAs. The mean age of patients with acquired CAAs was higher (64.7 years) compared with the congenital group (53.2 years). Ipsilateral myocardial infarction (MI) occurred in three of four patients with acquired CAAs but MI was not located on the same side as the aneurysm-bearing coronary artery (contralateral) in two patients with the congenital variety. In the patients with congenital CAAs, an aneurysm predilection site was observed in the proximal portion of the aneurysm-bearing vessel. Dual and multiple aneurysms were more common in the acquired CAAs. Although congenital CAAs were sizeable, the small-sized atherosclerotic CAAs developed complications more frequently. During an average follow-up of 7.9 years, only one patient died of a noncardiac cause and another developed recurrent uncomplicated non-Q wave lateral MI. Both subjects had atherosclerotic CAAs. In our series, no rupture or sudden death occurred. Coronary artery bypass grafting (CABG) was performed in three patients with acquired and in one patient with congenital CAAs. In the latter patient, simultaneous ligation of the congenital aneurysm associated with a coronary arteriovenous fistula was performed. Regarding antiplatelet and anticoagulant policy for the whole group, three patients were on aspirin, four were on acenocoumarol, and in another three subjects with congenital CAAs, a medical regimen was followed. Larger series, however, are required in order to elucidate further angiographic characteristics of acquired vs congenital CAAs.

Journal Article↗
PubMed1998

New method to evaluate myocyte remodeling from formalin-fixed biopsy and autopsy material.

BACKGROUND: Excessive lengthening of cardiac myocytes attributed to series addition of sarcomeres is a consistent feature of left ventricular dilation in chronic heart failure. Currently, it is not feasible to assess myocyte dimensions, particularly myocyte length, in a manner that is of potential diagnostic usefulness. METHODS AND RESULTS: Isolated myocytes from three groups of normal rats (100, 200, and 300 g) were obtained by using two different methods: (1) digestion of formalin-fixed myocardial tissue using potassium hydroxide (KOH) and (2) retrograde aortic perfusion of fresh hearts with collagenase. There was no difference in mean cell length between the two methods. The KOH method was also used to isolate intact, rod-shaped myocytes from formalin-fixed human cadaver left ventricles (control, n = 3; heart failure, n = 3) and from human right ventricle biopsy specimens (n = 6). Confirming our previous work using collagenase-isolated myocytes from fresh human explants, left ventricular myocytes from failing hearts showed longer mean cell length compared with control hearts. Data from human right ventricle biopsy specimens confirmed our previous finding in rats that myocyte lengthening is less pronounced in this chamber in heart failure. CONCLUSIONS: The KOH method can be used to obtain reliable measurements of myocyte length and other cellular parameters from myocardial biopsies and autopsy material. Such data may be useful in the diagnostic assessment of remodeling associated with heart failure.

Aged↗
PubMed1998

Renal osteodystrophy in dialysis patients: diagnosis and treatment.

This article reviews the clinical, biological, radiological, and pathological procedures and their respective indications for the practical diagnosis of the following various histological patterns of renal osteodystrophy: osteitis fibrosa due to parathyroid hormone (PTH) hypersecretion: osteomalacia or rickets due to native vitamin D deficiency and/or aluminum overload; and adynamic bone disease (ABD) due to aluminum overload and/or PTH secretion oversuppression. Our advice regarding bone biopsy is to restrict it to patients with symptoms and hypercalcemia, especially those who have been previously exposed to aluminum. In other cases, we propose relying merely on the determination of the plasma concentrations of calcium, protide, phosphate, bicarbonate, intact PTH, aluminum, 25(OH)D3, and alkaline phosphatase (total and bony if hepatic disease is associated) to choose the appropriate treatment. Because of the danger of the desferrioxamine treatment necessary to chelate and remove aluminum, the suspicion of aluminic bone disease (osteomalacia or ABD) will always be confirmed by a bone biopsy. In the case of nonaluminic osteomalacia, correction of the vitamin D deficiency by native vitamin D or 25(OH)D3, and of the calcium deficiency and acidosis by alkaline salts of calcium and if necessary sodium bicarbonate are sufficient to cure the disease. In the case of nonaluminic ABD, the stimulation of PTH secretion by the discontinuation of 1alpha hydroxylated vitamin D and the induction of a negative calcium balance during dialysis by decreasing the calcium concentration in the dialysate will allow an increase of the CaCO3 dose to correct for hyperphosphatemia without inducing hypercalcemia. For hyperparathyroidism, i.e., plasma intact PTH levels greater than two- or four-fold the upper limit of normal levels (according to the absence or presence of previous aluminum exposure), the treatment will consist in increasing the CaCO3 dose to correct for hyperphosphatemia together with a decrease of the calcium concentration in the dialysate if the dose of CaCO3 is so high that it induces hypercalcemia. When the hyperphosphatemia has been corrected and there is still a low or normal corrected plasma calcium level, 1alpha(OH)D3 in an oral bolus 2 or 3 times a week should be given at the minimal dose of 1 microg. When the PTH level stays above 400 pg while hypercalcemia occurs and hyperphosphatemia persists, surgical subtotal parathyroidectomy is recommended or the injection of calcitriol into the big nodular hyperplastic parathyroid glands under sonography control in high surgical risk patients. Special recommendations are given for children.

Adult↗
PubMed1998

Inhibition of gastric secretion by omeprazole and efficiency of calcium carbonate on the control of hyperphosphatemia in patients on chronic hemodialysis.

Contradictions exist in the literature regarding the effect of gastric secretion inhibition on phosphate absorption. In healthy controls, omeprazole would decrease the hyperphosphatemia or the hyperphosphaturia induced by an acute phosphate load, suggesting an inhibition of phosphate absorption. In chronic hemodialysis patients, gastric hypersecretion is associated with hyperphosphatemia, but inhibition of gastric hypersecretion by ranitidine in those receiving calcium carbonate (CaCO3) as a phosphate binder would paradoxically exacerbate their hyperphosphatemia. Because of these conflicting observations, we performed an open crossover study on 16 chronic stable hemodialyzed patients with a daily mean intake of 9.4+/-4 g of CaCO3, and we compared the plasmatic predialysis levels of phosphate, calcium, protides, bicarbonates, intact parathyroid hormone (PTH), urea, and creatininemia during 2 successive periods of 2 months, the first one without omeprazole and the second one with 20 mg omeprazole intake in the morning. Phosphatemia increased with omeprazole but not significantly from 1.80+/-0.38 to 1.89+/-0.42 mM whereas corrected calcemia decreased significantly (p = 0.04) from 2.41+/-0.18 to 2.36+/-0.16 mM as did bicarbonatemia from 26.7+/-3.5 to 25.7+/-3.1 mM (p < 0.05). No change in creatininemia or in blood urea was observed, suggesting the stable efficiency of dialysis as well as the stable intakes of protein and therefore of phosphate during the two study periods. In conclusion, inhibition of gastric secretion by omeprazole increases the plasmatic phosphate predialytic level but in a nonsignificant way. This increase may be explained by a slight but significant concomitant decrease of calcemia and bicarbonatemia. These results do not support the phosphate binding efficiency of CaCO3 being decreased by the inhibition of gastric acid secretion.

Absorption↗
PubMed1998

Maladaptive remodeling of cardiac myocyte shape begins long before failure in hypertension.

Progression to failure in hypertension is associated with ventricular dilation, excessive myocyte lengthening, and an increase in myocyte length/width ratio. The temporal development of these changes in relation to impaired pump performance is unknown. We examined isolated myocytes from 1- to 12-month-old spontaneously hypertensive heart failure (SHHF) rats who develop heart failure at approximately 24 months of age. Left ventricular myocyte cross-sectional area reached a maximum of approximately 350 to 400 microm2 at 3 months of age and did not change significantly thereafter. Nonetheless, LV systolic wall stress, a known stimulus for myocyte transverse growth, increased progressively between 3 and 12 months of age. Unlike the situation in normally aging rats with stable body mass, myocyte length in SHHF rats continued to increase with aging (P<0.05 from 9 to 12 months of age). In summary, (1) left ventricular myocyte transverse growth reaches an upper limit by 3 months of age although systolic wall stress continues to rise; and (2) cell length is significantly increased by 12 months of age. This study suggests that maladaptive remodeling of cardiac myocyte shape begins long before pump failure in hypertension. Additionally, it appears that the left ventricle may be robbed of an important adaptive mechanism to normalize wall stress (eg, myocyte transverse growth) early in the progression to failure.

Aging↗
PubMed1998

Measurement of isolated myocyte volume using the Coulter models Z2 and ZM/C256: a comparison of instrument function.

Changes in cardiac structure that depart from normal have generally been termed "remodeling". Assessment of ventricular remodeling at the cellular level should include measurement of myocyte dimensions. A well-established and reliable method to assess myocyte remodeling uses isolated cells and the Coulter Counter/Channelyzer system. The new Coulter Model Z2 has numerous modifications and improvements from the Model Z predecessor(s) interfaced to a pulse-height analyzer (e.g., channelyzer). Improvements of the Model Z2 over older instruments include: (i) elimination of the mercury manometer with accompanying oil-displacement pump; (ii) reduced size and weight; (iii) a higher degree of mechanization and automation; (iv) inclusion of an advanced comprehensive statistical package and (v) a substantial reduction in cost. The purpose of this study was to determine if the newly modified instrument produces the same results as the previous instrument combinations, which were shown to produce reliable cell volume data from irregularly shaped cells such as cardiac myocytes.

Animals↗
PubMed1997

Nd:YAG laser irradiation in conjunction with cryogen spray cooling induces deep and spatially selective photocoagulation in animal models.

Successful laser treatment of haemangiomas requires selective photocoagulation of subsurface targeted blood vessels without thermal damage to the overlying epidermis. We present an in vivo experimental procedure, using a chicken comb animal model, and an infrared feedback system to deliver repetitive cryogen spurts (of the order of milliseconds) during continuous Nd:YAG laser irradiation. Gross and histologic observations show deep-tissue photocoagulation is achieved, while superficial structures are protected from thermal injury due to cryogen spray cooling. Experimental observation of epidermis protection in chicken comb animal models suggests selective photocoagulation of subsurface targeted blood vessels for successful treatment of haemangiomas can be achieved by repetitive applications of a cryogen spurt during continuous Nd:YAG laser irradiation.

Animals↗
PubMed1997

Invasive versus non-invasive diagnosis of renal bone disease.

At present, bone histomorphometry remains the gold standard for the diagnosis of the various types of renal bone disease. In the search for a non-invasive method of diagnosis, biochemical serum markers of bone remodelling, in addition to serum intact parathyroid hormone and aluminium determinations, have been proposed as the most reliable tools and are at present widely used in clinical practice. Their respective diagnostic values, as separate items and in combined analysis, are thoroughly discussed in the present review.

Aluminum↗
PubMed1997

Cryogen spray cooling during Nd:YAG laser treatment of hemangiomas. A preliminary animal model study.

BACKGROUND: Successful laser treatment of hemangiomas requires selective photothermal destruction of dilated cutaneous vessels without damaging the overlying epidermis. Delivering a short cryogen spurt, on the order of milliseconds, has been shown to result in localized cooling of the superficial skin structures during laser irradiation. OBJECTIVE: The purpose of this study was to examine the effectiveness of cryogen spray cooling (CSC) in protecting superficial tissue structures during continuous Nd:YAG laser irradiation of an in vivo model hemangioma. METHODS: The highly vascularized chicken comb was selected as the animal model for hemangiomas. The Nd:YAG laser irradiation ranged from 2.6 to 35.1 J/mm2. A feedback system utilizing infrared radiometry monitored the comb surface temperature and controlled delivery time of the cryogen spurt. When comb surface temperature during laser irradiation reached 36-42 degrees C, a 30-100 msec cryogen spurt was delivered. Animals were euthanized 1 hour to 21 days following each experiment. Gross and histologic analyses were performed. RESULTS: Nd:YAG laser irradiation resulted in deep (up to 6.1 mm) tissue photocoagulation, while CSC preserved the overlying epidermis and papillary dermis. CONCLUSION: The results demonstrate that CSC is effective in protecting the epidermis and papillary dermis, while achieving deep tissue photocoagulation during Nd:YAG laser irradiation. Further pilot studies in humans appear warranted.

Aerosols↗
PubMed1997

TEM--minimal invasive therapy of rectal cancer?

The aim of this study is to outline the use of transanal endoscopic microsurgery (TEM) for local excision of rectal carcinoma. Thus the clinical and long-term results regarding endorectal excision of the rectal lesions at the University Hospital of Cologne and Berlin will be presented. During the period July 1983 till December 1993 the system has been employed on 405 cases (17.8% carcinomas) at the University Hospital of Cologne and on 60 cases (20% carcinomas) during the period September 1994 till September 1996 at the University Hospital of Berlin, Charité. Early postoperative complications consisted of intraperitoneal perforations (five cases); rectovaginal fistulas (four cases); haemorrhages (four cases), death due to cardiopulmonary failure (two cases). All the complications occurred within the first 4 years of the learning phase. The cancer-specific 3-year survival rate of patients with "low risk" pT1 cancers amounted to 91%. Two recurrences after local excision of pT1 cancers occurred 1 year postoperatively, which were treated successfully using the TEM system. Most of the histologic findings of the subsequent radical operations following local resections of infiltrative rectal cancers revealed that the carcinoma had already been totally removed. The main indication for TEM is the removal of sessile adenomas. Early rectal carcinomas (pT1) of the "low risk" type, with favourable histological grading (grade 1 and 2) and clinical staging (CS I) were also considered for endorectal therapeutical approach. Even though our initial results do show encouraging results, regarding endorectal excision of pT2 cancers, more experience is needed to clarify the indication for locally amenable pT2 cancers of the "low risk" type and rule out the role of adjuvant therapy after complete excision of these carcinomas. The indication for TEM encloses also confined (< 4 cm) infiltrative cancers (> pT1) in cases where the patient is unwilling to undergo extensive surgery or due to medical reasons. The technique allows accurate endoscopic microsurgical excision of early cancers for cure with minimal morbidity and excellent presentation of specimen for complete histological analysis. Diligent follow-up is mandatory, since most (60-80%) of local recurrences can be treated successfully. Thus demolitive surgery can be avoided in selected cases with rectal cancer.

Adenoma↗
PubMed1997

[Introduction of video endoscopic vascular surgery of the pelvic area].

The fact that operative lethality and other typical postoperative complications following surgical treatment of aortoiliac atherosclerotic disease are mainly related to the surgical trauma (derived from the extensive abdominal incision and dissection), but not to the classical arterial reconstruction itself, has led us to develop a videoendoscopic aortoiliacal surgical method which is supposed to diminish the potential postoperative complications. Thus, a new endoscopic instrument set for vascular surgery has been developed in close cooperation with Aesculap AG Tuttlingen, Germany. After evaluating the basic techniques of videoendoscopic patching and end-to-side anastomosis with the newly designed instruments on a training model (n = 50), the feasibility of videoendoscopic vascular surgery on aortoiliacal vessels was tried out on human corpses (n = 8). The positive results of the initial survey have finally encouraged us to conduct our first series of animal studies on piglets (n = 25). The investigation regarding ultrasonically monitored blood flow in the femoral arteries after videoendoscopic aortofemoral bypass grafting and other systemic, hemodynamic parameters showed positive results. No complications were encountered in any of the standardized animal studies. Favorable activity levels were recorded. Meanwhile we have performed 5 extraperitoneal videoendoscopic aortofemoral artery bypasses in patients with aortoiliac occlusive diseases. One patient in whom we had occluded the inferior mesenteric artery died due to an ischaemic colitis. The other patients had an uneventful postoperative course. The videoendoscopic vascular procedures were carried out according to the rules of conventional vascular surgery. Nevertheless, further experimental research and development of endoscopic instruments have yet to be done, to optimize the new surgical method and to clarify the advantages of videoendoscopic vascular surgery.

Animals↗