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Biomedical subjects

F Stephan

Publications and source records attributed to F Stephan.

At least 19 recordsLinked to original sources
PubMed1998

Determination of total effective vascular compliance in patients with sepsis syndrome.

Changes in capacitance vessels have important consequences on cardiac filling pressure and fluid volume distribution in patients with sepsis syndrome. Vascular compliance may be evaluated from the slope of the relationship between changes in total blood volume (deltaTBV) and changes in central venous pressure (deltaCVP) during acute volume expansion (450 ml of gelatin fluid over 6 min), i.e., from the deltaTBV/deltaCVP ratio. The mean ratio (ml x mm Hg-1 x kg-1) was 2.03 +/- 0.21 in control subjects, 1.43 +/- 0.25 in mechanically ventilated patients without sepsis syndrome, and 0.94 +/- 0.24 in mechanically ventilated patients with sepsis syndrome (p < 0.0001 versus the other two groups). Based on echocardiographic determinations, cardiac performance was constantly found within the normal range (cardiac output ranged from 5.6 +/- 1.2 to 6.7 +/- 2.0 L/min in nonseptic patients from 6.8 +/- 1.9 to 7.8 +/- 2.2 in septic patients). Effective compliance of the total vascular bed is therefore reduced in patients with sepsis syndrome, independently of the hemodynamic modifications due to mechanical ventilation.

Adolescent↗
PubMed1998

Risk factors and outcome of nosocomial infections: results of a matched case-control study of ICU patients.

Intensive-care-unit (ICU) patients are at risk for both acquiring nosocomial infection and dying, and require a high level of therapy whether infection occurs or not. The objective of the present study was to precisely define the interrelationships between underlying disease, severity of illness, therapeutic activity, and nosocomial infections in ICU patients, and their respective influences on these patients' outcome. In a 10-bed medical ICU, we conducted a case-control study with matching for initial severity of illness, with daily monitoring of severity of illness and therapeutic activity scores, and with analysis of the contribution of nosocomial infections to patients' outcomes. Forty-one cases of patients who developed nosocomial infections during a 1-yr period were paired with 41 controls without nosocomial infection according to three criteria: age (+/- 5 yr), Acute Physiology and Chronic Health Evaluation II (APACHE II) score (+/- 5 points), and duration of exposure to risk. Successful matching was achieved for 118 of 123 (96%) variables. Neurologic failure on the third day after ICU admission was the sole independent risk factor for nosocomial infection (adjusted odds ratio [OR]: 1.34; 95% confidence interval [CI]: 1.09 to 1.64; p = 0.007). Unlike control patients, case patients showed no clinical improvement and required a high level of therapeutic activity between ICU admission and the day of infection. Mortality attributable to nosocomial infection was 44%. Excess length of stay and duration of antibiotic treatment attributable to nosocomial infection were 14 d and 10 d, respectively. Attributable therapeutic activity as measured with the Therapeutic Intervention Scoring System (TISS) and Omega score was 368 and 233 points, respectively. Such consequences were observed in patients who developed multiple infections. These findings suggest that a persistent high level of therapeutic activity and persistent impaired consciousness are risk factors for nosocomial infections in ICU patients. These infections are responsible for excess mortality, prolongation of stay, and excess therapeutic activity resulting in important cost overruns for health-care systems.

APACHE↗
PubMed1997

[Prevention of acquired pneumonia during artificial ventilation (excluding the use of anti-infectious agents)].

Nosocomial pneumonia remains a serious complication which occurs in patients who are artificially ventilated; as neither frequency nor important sequelae have altered recently inspite of the progress which has been achieved both with diagnosis and treatment. Preventative measures ought to be developed and realistically assessed before their introduction. Today it is indispensable to measure the impact of these measures, whether they have been previously or recently proposed by therapeutic trials. The current techniques proposed to prevent the appearance of nosocomial pneumonia are integrated in the usual conventional group of measures in the struggle against nosocomial infection which rests predominantly on standard approaches to hospital hygiene. These may be more specifically directed at good practical measures for the care of the ventilated patient. Regular toilet to the digestive and respiratory pathway, care of the ventilator material, absence of the changing of ventilation tubing during the stay. A certain number of measures are specifically suggested to prevent pneumonias: they have been imperfectly evaluated in clinical practice and remain controversial. Thus selective decontamination of the digestive system has not been dealt with her but also the sitting position, the utilisation of turning or oscillating beds, the continuous aspiration of oropharyngeal secretions or the use of Sucralfate as a means of prevention stress ulcers. Today, and until a complete evaluation of different techniques, the prevention of acquired pneumopathy during artificial ventilation rests above all on extremely simple measures; these cost little and are essentially meticulous care of the upper respiratory and digestive apparatus, to tracheal aspiration and physiotherapy which assure effective drainage and secretions, the use of the semi-sitting position, a well positioned gastric tube, in other words, basic care of the ventilated patient of a very good quality.

Beds↗
PubMed1994

Mortality attributable to nosocomial infections in the ICU.

Although a direct relationship between nosocomial infection and mortality in intensive care unit (ICU) patients has not always been demonstrated formally, it is possible to conclude that nosocomial infections increase the risk of death in critically ill patients. A more precise analysis indicates that: 1) this effect is highly probable for pneumonia, doubtful for bacteremia, and uncertain for urinary tract infection; 2) risk increases with duration of stay in the ICU; 3) bacterial etiology modifies the risk; and 4) this effect is stronger in less severely ill patients, probably because the severity of underlying disease remains the most significant factor.

Bacteremia↗
PubMed1994

Evaluation of human cytomegalovirus latency in alveolar macrophages.

Cytomegalovirus (CMV) pneumonia is a major cause of illness in immunocompromised patients. The sites of human CMV (HCMV) latency are still not clearly defined. The present study was therefore designed to investigate the hypothesis that alveolar macrophages could constitute such a site. DNA extracted from alveolar cells collected by bronchoalveolar lavage and blood mononuclear cells (BMC) from asymptomatic nonimmunocompromised CMV-seropositive and CMV-seronegative patients were investigated. Controls consisted of DNA from a CMV-infected MRC5 cell line, BMC and alveolar macrophages from patients with acute CMV infection. Polymerase chain reaction (PCR) was designed for detection of a 290-bp fragment of the promoter region of the major immediate early gene of HCMV conserved within the various HCMV strains and without homology with the human genome. The limit of detection of the method was evaluated to be one HCMV viral copy per 10(4) cells. HCMV DNA was detected in BMC or alveolar cells of all patients with acute CMV infection. In contrast, no HCMV DNA was detected in alveolar cells and BMC from nonimmunocompromised asymptomatic HCMV-seropositive patients. In conclusion, in the present experiment, no latent HCMV could be detected in alveolar cells collected in nonimmunocompromised asymptomatic CMV-seropositive patients.

Adult↗
PubMed1990

[Expanded trans-pedicular spongiosa grafting--dorsal approach to filling of the intervertebral spaces with cancellous bone].

Internal fixation of dorsolumbar spinal fractures can be accomplished by dorsal plating or internal fixator. So far, the technique of transpedicular grafting has been applied to fill the vertebral body with cancellous bone. In this paper, we present a new technique of extended transpedicular bone grafting to fill the intervertebral space also. By this means, the disadvantage of secondary loss of height after removal of the metal implants can be prevented.

Bone Plates↗
PubMed1989

Nonsuture microsurgical vessel anastomosis using an absorbable cuff.

The nonabsorbable cuff used for nonsuture anastomosis can cause residual vessel stenosis as well as regional wall rigidity. Resulting disturbances in laminar flow promote the development of irregularities in the intimal endothelial vessel lining distal to the anastomosis. Using absorbable cuffs, the degree of stenosis can be appreciably reduced, thereby diminishing thrombogenic flow turbulence. The absorbable cuff can thus facilitate clinical application of nonsuture microsurgical vessel anastomosis.

Anastomosis, Surgical↗
PubMed1984

The role of insulin, glucagon and growth hormone in the regulation of plasma glucose and free fatty acid levels in anorexia nervosa.

It is well established that glucagon plays an important role in the regulation of fuel supplies as its plasma level increases during the first days of a complete fast. However, it is not certain that glucagon is involved in the adaptation to chronic starvation. In the present study, this problem was investigated by the determination of the changes in the plasma glucagon level elicited by an i.v. glucose tolerance test followed by an i.v. arginine perfusion in 26 self starved patients suffering from anorexia nervosa (AN) and 14 control patients having only minor neurotic disorders. The basal plasma glucagon level tended to be higher in the AN patients than in the controls; but the difference was not statistically significant. Glucagon responses to glucose and arginine observed in the AN patients were not significantly different from those seen in the control patients. In the AN patients, the insulin response to both loads was reduced and the plasma GH level increased paradoxically after the glucose load, whereas it rose normally after the arginine load. It may be concluded that in chronic starvation by AN the regulation of fuel supplies depends mainly on decreased insulin and increased growth hormone secretion. The role of glucagon seems to be of minor importance in this condition.

Adolescent↗
PubMed1984

Histomorphometric study of the enhancement of renal compensatory hypertrophy by ACTH in the rat.

In the female adult rat, renal compensatory hypertrophy is greatly enhanced by hyperadrenocorticism elicited by the administration of ACTH given at a dose of 18 Y/100 g BW/d for 7 days after uninephrectomy (UN). This renotrophic effect of ACTH is particularly prominent in rats drinking a NaCl solution (9 g/l). In the present experiments, we performed histomorphometrical measurements of the glomerular tuft (GT) and the proximal tubule (PT) in the hypertrophying kidney (HK) remaining 7 days after UN in 10 rats treated with ACTH and 7 control animals. The histologic preparations were examined under light microscopy with the "Kontron" image analyzer. ACTH increased the weight of the HK (1213.8 +/- 20.3 mg versus 1037.3 +/- 13.3, p less than 0.001) and determined an enlargement of the cross sectional area of the GT (12559 +/- 3351.3 mu2 versus 10486 +/- 407.5, p less than 0.01) and of the epithelial area of the PT (1751 +/- 40.8 mu2 versus 1586 +/- 41.5, p less than 0.025). These morphometrical data are consistent with the increased Protein/DNA ratio - a marker of cellular hypertrophy - found in other rats studied under the same experimental conditions. The increased weight gain of the HK elicited by ACTH is related to the hypertrophy of the epithelial cells of the PT and possibly to an enlargement of the glomeruli.

Adrenocorticotropic Hormone↗
PubMed1984

[Bromocriptine and the growth hormone response to thyroliberin in the insulin-dependent diabetic].

The effect of bromocriptine on growth hormone (GH) responses to TRH was studied in 14 insulin-dependent diabetics. The effect of this dopaminomimetic agent was inconstant. In the 6 patients with inadequate responses of GH to TRH, bromocriptine inhibited this response. Inversely, it appeared capable of stimulating a GH response in certain non-responders. The could suggest the existence of disturbances of dopaminergic control of GH secretion in diabetics, but the lack of reproducibility of responses of GH to TRH makes this an uncertain conclusion.

Adolescent↗
PubMed1983

[Asymptomatic thyroid dysfunction. Routine detection using the free thyroxine index].

Free plasma thyroxine index (FT4I) and plasma concentrations of triiodothyronine (T3) were routinely determined on admission in 1862 hospital patients without signs or history of thyroid dysfunction. Total thyroxine (T4) and FT4I values were beyond confidence limits in 16.3% and 7.5% respectively of the patients, whereas T3 values were low in 23%. Among the 84 patients with high FT4I, 31 had clinically unsuspected hyperthyroidism confirmed by the TRH test (T3 increased in 66% of the cases). Among the 46 patients with low FT4I, 14 had demonstrable hypothyroidism (low T3 in 65% of the cases). In this population, the prevalence of proven thyroid dysfunction without clinical symptoms was 1.66% for hyperthyroidism and 0.75% for hypothyroidism. The diagnostic value of normal FT4I was estimated at 50%. The persistence of an abnormal FT4I on a second determination indicated the presence of hyperthyroidism in 72% of patients with high FT4I values and of hypothyroidism in 74% of patients with low FT4I values. In doubtful cases, TSH assays or TRH tests led to the concept of "transient" dysthyroidism, and the potential total prevalence of routinely discovered dysthyroidism could be estimated at 3.54% including 2.47% for hyperthyroidism. The latter occurred in 95% of people older than 50, with a sex ratio of 0.94. The cost of diagnosis for each new case clinically unsuspected hyperthyroidism is 1200 Z, but this could be reduced to 450 Z if only patients over 50 years of age were investigated and if FT4I determinations were replaced by free T4 determinations.

Adult↗
PubMed1983

[Modification of the renotrophic action of adrenal hypercorticism by nutritional factors in uninephrectomized rats].

In the rat renal compensatory hypertrophy (RCH) was enhanced by hyperadrenocorticism induced by the administration of a long acting ACTH at a dose of 18 Y/100 g body weight/d. for 7 d. after uninephrectomy (UN). In the present experiments we compared the differences delta between the weight, the content in protein, RNA and DNA of the left solitary kidney and the same determinations done on the right kidney excised at UN 7 d. earlier. The rats drank freely a isotonic solution of NaCl (G1) or KCl (G2) or glucose (G3, G4). The rats of group G1, G2 and G3 received a standard solid food; the G4 rats ate a K poor diet. About half of the animals were treated with ACTH. RCH occurred in all the rats even when they lost body weight. The gain in weight of the solitary kidney was enhanced in all the rats treated with ACTH but not in the G2 rats loaded with KCl. This renotropic action of hyperadrenocorticism was most prominent in the K depleted G4 rats. The protein/DNA ratio, a marker of cellular hypertrophy, was increased by hyperadrenocorticism in the G1 and D2 rats drinking respectively the NaCl or the KCl solutions. This ratio did not change in the ACTH treated G3 and G4 rats drinking the glucose solution suggesting that, in this experimental condition, cellular hyperplasia and hypertrophy occurred at the same extent. These experiments suggest that, in the uninephrectomized rat, the renotrophic action of ACTH is modulated by nutritional factors. The enhancement of RCH by ACTH may be related to hyperglycemia, hyperinsulinism or altered handling of Na and K by the nephron.

Adrenal Glands↗
PubMed1982

[Serum beta 2 microglobulin assay in diabetes mellitus (author's transl)].

Beta 2 microglobulin (beta 2m) is continuously produced and subsequently almost exclusively eliminated by glomerular filtration (GRF). There is a strong correlation between serum beta 2m and serum creatinine concentrations. Beta 2m assay however seems to enhance diagnostic accuracy of minor decreases in GRF. Serum beta 2m concentrations were assayed in 193 consecutive patients with diabetes mellitus. They correlated well with serum creatinine. Supranormal serum beta 2m concentrations (greater than 2.4 micrograms/lm) were found in 15.5% of patients with normal serum creatinine. Increase in beta 2 m/was related to poor metabolic control of diabetes and correlated positively with glycosylated hemoglobin concentrations. Serum beta 2m concentrations were also related to the duration of recognized diabetes. Serum beta 2m assay allows early detection of GRF disorders in patients with diabetes mellitus. Such disorders may be partly reversible once metabolic control is improved.

Adolescent↗
PubMed1982

[Hormonal adaptation to chronic self-starvation in patients with anorexia nervosa (author's transl)].

An intravenous glucose tolerance test (glucose 0.33 g/kg bodyweight) was performed in 35 women with chronic anorexia nervosa (AN) and in 19 age-matched women of normal weight. Plasma free fatty acids (FFA), immunoreactive insulin (IRI) and growth hormone (GH) levels were measured before and after the test. Although the mean value of glucose disappearance rate K was significantly reduced in the patient group as compared with the control group, K was in fact normal (greater than or equal to 1.10 +/- 10(-2)) in 20 anorectic women (AN 1) and lowered in 15 (AN 2). The basal and post-stimulation IRI levels were decreased in all anorectic women, but particularly in the AN 2 group with impaired glucose tolerance. The glucose load elicited a striking rise in GH in patients of the AN 2 group, a slight increase in those of the AN 1 group and no change in women of the control group. FFA values before the test were high mainly in the AN 2 patients but the difference with reference values did not reach statistical significance owing to the large s.e.m. After the glucose load there was a similar decrease in FFA levels in all three groups, but levels in the AN 2 group remained significantly higher than in the control group. Hyposecretion of IRI and hypersecretion of GH may account for the impaired glucose tolerance observed in all patients of the AN 2 group. Both hormonal changes facilitate neoglucogenesis and lipolysis, thereby providing the energy substrates required for survival of the self-starved subjects. The anorectic women also had low plasma T3 enabling adjustment of the oxidative metabolism to the reduced food supply.

Adolescent↗
PubMed1982

Effect of diabetic control on the level of circulating thyroid hormones.

Basal plasma levels of thyroxine (T4), triiodothyronine (T3) and reverse T3 were determined by radioimmunoassay in 44 control subjects, 44 Type 1 (insulin-dependent) and 39 Type 2 (non insulin-dependent) diabetic patients aged from 15 to 75 years. All were clinically euthyroid. The quality of diabetic control was assessed by the percentage of glycosylated haemoglobin. In both the diabetic groups there was a significant decrease in T3 and a rise in reverse T3 whereas T4 was normal. We found no significant differences between plasma thyroid hormone levels in Type 1 and Type 2 diabetic patients. In the poorly controlled diabetics (glycosylated haemoglobin greater than or equal to 12%), T3 was 90 +/- 5 ng/dl, which differed significantly from the level found in the better controlled patients (106 +/- 5 ng/dl, p less than 0.01). In the diabetic patients without associated illness, a negative linear correlation was found between T3 and glycosylated haemoglobin and a positive correlation between reverse T3/T3 and glycosylated haemoglobin. No correlation between T3 or reverse T3 and fasting blood glucose could be established. In conclusion, many diabetics showed a low T3 syndrome suggesting that there may be an impairment in the extrathyroidal conversion of T4 to T3. This may well be enhanced by a poor diabetic control (glycosylated haemoglobin greater than or equal to 12%).

Adolescent↗