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[Macrosomia of the fetus and clinical relevance].

The clinical relevance of foetal macrosomia (i.e. birth weight greater than or equal to 4000 gms) was investigated retrospectively using the 1987 figures of the "Bayerische Perinatalerhebung". 8591 (total n = 101931; 8.4%) newborns met the criterion for macrosomia and were compared with two groups of normosomic newborns (birth weight 2500-2999 gms and 3000-3999 gms). The problems, which may obscure correct prenatal diagnosis are discussed. The incidence of operative deliveries and birth injuries was increased. The duration of the deliveries was not prolonged in our study in contrast to published reports. The neonatal transfer-rate to a neonatal centre was higher in newborns, delivered by Caesarean section, compared with newborns delivered by the vaginal route. The perinatal and the maternal morbidity was higher, the perinatal mortality lower in the macrosomic newborn. According to our data, macrosomia represents and elevated perinatal risk.

Asphyxia Neonatorum

[Does Campylobacter Helicobacter pylori infection have a clinical relevance? Methodologic, epidemiologic and clinical studies].

The authors searched for Campylobacter pylori (CP) in gastric biopsies from 180 patients by means of microbiological culture. Warthin-Starry staining and urease activity determination. 50 patients with CP-positive antral gastritis were treated with bismuthsubsalicylate 2.4 g per day for 3 weeks, followed by a therapy-free interval of 7-10 days and then a control biopsy was performed. Combined results of bacterial culture and histology proved to be mostly reliable. The prevalence of CP in Hungary is similar to other European countries. CP-positivity was found at the following rates: endoscopically normal patients 30%; stump gastritis 30%; antral gastritis 75%; duodenal ulcer 89%. In all CP-positive cases chronic antral gastritis was seen, whereas normal antral mucosa was never CP-positive. There was no correlation between dyspeptic complaints and CP-positive chronic antral gastritis. Both decreased after bismuth therapy independently on the elimination of CP. CP-positivity in 2/3 of the control investigations points to fast recolonization. The clinical relevance of the CP-infection seems to be questionable.

Adolescent

[Has Campylobacter pylori infection any clinical relevance? Methodologic, epidemiologic and clinical studies].

The occurrence of Campylobacter pylori (CP) was studied in 180 patients referred for endoscopy. The bacterium was detected by culture, histology (Warthin-Starry staining) and urease test of antral biopsy samples. Patient groups were formed according to endoscopic diagnoses, clinical symptoms and antral mucosal histology. 50 CP positive patients with chronic antral gastritis were treated by bismuth subsalicylate (2,4 g/day) for 3 weeks. Positivity by culture and/or silver-stained histology proved to be the most reliable way for detecting CP. CP was proved in about 30% in patients with normal gastroduodenum (13/42) or with stump gastritis (4/15), in 75% with endoscopic antral gastritis (51/68) and in 89% with duodenal ulcer (49/55). A close relationship between CP and histological chronic antral gastritis could be demonstrated. No causal link between CP positive chronic active antral gastritis and non-ulcer dyspepsia could be verified. The decrease in histological activity of chronic gastritis and in dyspeptic complaints after bismuth salt therapy was found to be independent of CP elimination. The results of control investigations following a therapy-free interval of 7-10 days speak in favour of CP recolonialisation within a relativelly short period. It can be concluded that, despite the undeniable relationship between CP and chronic antral gastritis and duodenal ulcer, further studies are necessary to clarify the clinical relevance of the CP infection.

Campylobacter Infections

Effect of reference point on visual evoked potentials: clinical relevance.

For clinical purposes the VEP is generally recorded from the mid-occipital region referenced to the vertex or mid-frontal region. This may lead to interpretive errors that can be avoided if a relatively inactive reference point, such as linked mastoids, is used simultaneously. The additional recording derivation may also be helpful in clarifying aberrant or ambiguous wave forms. The diagnostic yield from the two montages is similar, although the linked-mastoid reference provides a greater number of technically inadequate recordings due to smaller size of P100 and increased contamination by muscle artifact.

Adolescent

The clinical relevance of sex selection techniques.

Clinical and laboratory attempts to alter the sex ratio require more complete and thorough study. Improved identification of Y-bearing sperm through chromosome evaluation rather than by F-body identification is critical to provide a more precise definition. The tentative conclusions stated below are based on an assessment of literature from which it is generally difficult to draw conclusions: 1. The timing of intercourse in relation to ovulation and subsequent fertilization appears to influence the sex ratio. More females are conceived when coitus occurs relatively close to ovulation, and more males are conceived when the sperm or egg is in the reproductive tract for a relatively longer time before conception. The influence of coital timing on the sex ratio is overall quite subtle and is not a practical method to alter the sex ratio for individual couples. 2. The use of ovulation-inducing medications slightly favors female offspring. A decrease in sex ratio of 5% to 10% has been shown in multiple studies. 3. Artificial insemination with fresh donor or homologous spermatozoa results in more male births with a reported 7% to 10% increase in the sex ratio. It appears that ovulation induction combined with artificial insemination cancels the respective influences of each on the sex ratio. 4. Sperm separation techniques using albumin (for selection of Y-bearing sperm) or Sephadex column filtration (for selection of X-bearing sperm) are the only techniques that have been reported to alter the sex ratio to a degree that is clinically relevant. Although clinical birth data are just beginning to accumulate, these methods appear to have a 70% to 80% success for selection of assumed Y-bearing sperm and a 75% to 80% success for selection of assumed X-bearing sperm. The validity of these results will remain questionable until fully detailed accounts are published and successfully repeated. Free-flow electrophoresis appears to achieve significant separation; however, the depressed postprocedure spermatozoa motility presently limits the usefulness of this procedure. 5. There is a potential to combine clinical and laboratory methods to maximize the efficiency of sex selection for interested couples. Modern methods to identify ovulation (e.g., urinary LH kits, ultrasonography) may help the timing of coitus for sex selection. Clomiphene citrate may enhance female sex preselection when Sephadex column filtration is also employed. 6. The priority of sex preselection in terms of medical, social, and demographic consideration remains to be determined. The avoidance of sex-linked genetic disorders is a reasonable and desirable goal.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Separation

[The clinical relevance of sonography in intensive care units].

336 sonographic examinations were performed with a portable ultrasound scanner on 217 patients in intensive-care units. In 302/336 (90%) cases, the region of clinical interest could be demonstrated completely or mostly by ultrasound. The clinical question could be answered by ultrasound in 270/310 (87%) cases partially. In 17/210 (5%) cases the clinical question could not be answered by ultrasound, in 26/336 (8%) cases there was no clinical question at all. 211/336 (63%) sonographic examinations were retrospectively classified as clinically relevant. A large part of clinically relevant examinations was found at the sonographic evaluation of the liver (100%), of the pericardium (96%), of the kidneys (89%), of the blood vessels (80%), of the gallbladder (78%), of the pleural space (76%) and on sonographic evaluation of patients with blunt abdominal trauma (91%). A relatively small part of clinically relevant examinations was found at sonographic evaluation of circumscribed or free intraabdominal fluid (59% resp. 57%), of cholestasis (53%) and of suspected neoplasm (11%). Sonographic examinations of the pancreas (40%) or the spleen (33%) and examinations without any clinical question (50%) also showed little clinical relevance.

Critical Care

Pelvic manifestations of diffuse idiopathic skeletal hyperostosis (DISH): are they clinically relevant?

This is a cross-sectional, case-controlled study on the clinical relevance of diffuse idiopathic skeletal hyperostosis (DISH) in relation to the pelvic girdle. Thirty-two rheumatology patients with DISH were compared with 35 dermatology control subjects in respect to the clinical parameters pain and passive hip joint motion in a standardized manner. There were no significant differences between the two groups, indicating no major clinical relevance of DISH in the pelvic region. In a second study, the radiographs of 23 DISH probands were compared blindly with 23 matched controls. The only significant difference was a much higher degree of severe juxtaarticular bone formation in DISH probands. The majority of these spurs proved to be asymptomatic and did not affect the range of passive hip joint mobility. DISH is a frequently seen, often radiologically very impressive phenomenon of little clinical relevance, at least in the pelvic area.

Aged

Prevalence of clinically relevant bacteremia after upper gastrointestinal endoscopy in bone marrow transplant recipients.

PURPOSE: To determine the prevalence of clinically relevant bacteremia after upper endoscopy in patients undergoing bone marrow transplantation. PATIENTS AND METHODS: We retrospectively reviewed the records of 151 patients who received an HLA-identical allogeneic bone marrow transplant (BMT) at the Seattle Veterans Affairs Medical Center between September 1983 and December 1988. Forty-seven patients who required esophago-gastroduodenoscopy (EGD) during their first 100 days after transplant were selected for evaluation. Clinically relevant bacteremia was defined as the development of hypotension, temperature greater than 38.5 degrees C, and a positive blood culture occurring within 24 hours after endoscopy. The presence of acute graft-versus-host disease (GVHD) at the time of endoscopy and the use of prednisone prior to endoscopy were considered possible risk factors for the development of bacteremia. The proportion of subjects who became bacteremic were compared using Fisher's exact test. RESULTS: Within 24 hours following endoscopy, nine patients (19%) developed clinically evident bacteremia (hypotension, temperature greater than 38.5 degrees C, and a positive blood culture). Eight of 14 patients receiving prednisone at the time of endoscopy developed bacteremia, compared to one of 33 not receiving prednisone (p less than 0.01). Nineteen patients had acute GVHD of at least grade 2 at the time of EGD, six of whom developed bacteremia. Although acute GVHD alone did not increase the risk of post-EGD bacteremia in patients not receiving prednisone (one of 21 versus zero of 12, p greater than 0.9), the risk of bacteremia was particularly high in patients with acute GVHD treated with prednisone at the time of EGD (six of seven). CONCLUSION: Allogeneic BMT recipients receiving prednisone for immunoprophylaxis after grafting or for treatment of acute GVHD are at high risk for clinically relevant bacteremia following EGD. Such patients are candidates for antibiotic prophylaxis prior to endoscopy.

Bone Marrow Transplantation

Clinical relevance of research on the structure of human chorionic gonadotropin.

Human chorionic gonadotropin (hCG) has been studied extensively over the past 10 years, and some structural correlates of its chemical, biological, and immunologic properties have been defined. A review of these observations and their relevance to clinical applications of methods for detecting hCG is presented.

Carbohydrates

Defecography in patients with anorectal disorders. Which findings are clinically relevant?

To evaluate the results and clinical impact of defecography in patients with anorectal disorders, 100 results of defecographic examinations from 92 patients were reviewed. The defecographic results were screened for the anorectal angle, defined both at rest and during straining, perineal descent, and abnormalities of the rectal configuration during straining. Anal manometry, saline infusion test, rectal capacity measurement, and anal electromyography (EMG) were also performed. There was a significant difference (P less than 0.001) both at rest (22 degrees) and during straining (12 degrees) between the two anorectal angle measurements. Incontinent patients had a larger anorectal angle, both at rest and during straining, than continent patients (P less than 0.04), but with a large overlap. The anorectal angle was not influenced by gender or age. An abnormal rectal configuration was found in 62 defecographic examinations. From the 8 patients with rectopexy performed for a large rectocele or intussusception, incontinent patients with an intussusception had the best results. In four patients, anal EMG showed an increased activity of the external sphincter during straining. Two of these four patients had abnormal defecograhic results. No correlations were found between anorectal angle and the other function tests. In conclusion, the anorectal angle lacks clinical relevance. In patients with defecation problems, defecography may be indicated whenever other investigations (physical examination, anal manometry, anal EMG) have excluded local pathology or a spastic pelvic floor syndrome. In these situations, defecography could detect an intussusception, which could easily be treated with rectopexy.

Aged

Single hemorrhage: a clinically relevant canine model of hemorrhagic shock.

Clinically encountered hemorrhagic shock is usually caused by a single, rapid hemorrhage secondary to trauma. Experimental models of shock, however, have utilized anesthetic agents and hemorrhage protocols which may compromise the clinical relevance of their findings. This report characterizes the response of conscious, splenectomized dogs to a single hemorrhage of varying rates and volumes, uncomplicated by the presence of anesthetic agents. The duration of a 40 ml kg-1 hemorrhage affected the magnitude of blood pressure recovery, but did not alter the decompensating drop in blood pressure. The shortest hemorrhage duration was chosen for further study, as the blood pressure profile for this hemorrhage duration demonstrated most clearly the recovery, plateau, and decompensation phases. Increasing the hemorrhage volume to 43 ml kg-1 caused a reproducible decrease in the magnitude of the blood pressure recovery, the time to decompensation, and the time to death. Splenectomized dogs, then, demonstrate a reproducible response to a fixed-volume hemorrhage, making chronically instrumented conscious dogs a good animal model with which to study the progression of hypovolemic shock.

Animals

[Ultrasound diagnosis of lumbar intervertebral disk displacement--a clinically relevant method?].

UNLABELLED: In a prospective clinical study, 102 patients suffering from low back pain were examined by ultrasound. In all patients the segments L3/4, L4/5, and L5/S1 were evaluated. We analysed a total of 306 lumbar disc segments. Ultrasound evaluation was transabdominally performed by using a 3,5 MHz scanner. The results of the ultrasound documentation were compared to MRI or if the patient was operated on with the intraoperative findings. In 25 disc the dorsal border of the disc could not be demonstrated by ultrasound. The statistical analysis resulted in the following values: [table: see text] Comparing these results with the results of other imaging modalities like myelography, CT, or MRI, ultrasound scores are significantly inferior. CLINICAL RELEVANCE: With the present technique ultrasound does not seem to be of diagnostic value for patients with herniated disk.

Adolescent

[Regression of coronary atherosclerosis: possible--and clinically relevant?].

Several recent clinical trials have shown that in male patients with stable coronary heart disease, progression of atherosclerosis can be delayed even in short time. The interventions to bring about less progression and even a regression of coronary artery lesions mainly consisted in lowering high lipid levels, either with drugs, partial ileal bypass surgery or comprehensive lifestyle changes. The results of trials using calcium antagonists were less consistent and failed to show clear-cut slowing or prevention of progression. Some questions, however, arise and are discussed: i.e. the shortcomings of quantitative angiography to assess the extent of atherosclerotic lesions and the clinical importance of the observed changes in luminal diameter, which tended to be small. Despite these intriguing issues, the reported studies provided the additional information that the angiographically demonstrated benefits were paralleled by a reduction of clinical vascular events and an improvement of the short-term clinical outcome.

Coronary Angiography

Neonatal therapeutic drug monitoring--its clinical relevance.

The potential clinical usefulness of therapeutic drug monitoring (TDM) in neonates is discussed. The personnel performing neonatal TDM must be knowledgeable in the many clinical, analytical, and pharmacokinetic variables used for measuring drug concentrations to formulate rational, individualized dosing regimens. Examples of variables and their effects on TDM interpretations are given and some gaps in our knowledge are presented. The theoretical promise of neonatal TDM is contrasted with the practical realities.

Humans

Right coronary artery disease. Pathophysiology, clinical relevance, and methods for recognition.

Among the clinical manifestations of ischemic heart disease, right coronary artery (RCA) disease offers a wide variety of right and left ventricular ischemic involvement, including prevalent right ventricular dysfunction and severe cardiac failure. Whether the right ventricular impairment is dependent primarily on ischemia of the right ventricle or requires a concomitant left ventricular dysfunction remains debatable. To assess the pathophysiology and clinical relevance of RCA-related ischemia, a systematic study of patients with single RCA disease (either vasospastic angina at rest or typical stable angina) was undertaken by radionuclide ventriculography. A high incidence of ischemia-induced right ventricular dysfunction was observed (93% and 95% in angina at rest and on effort, respectively), either alone or associated with left ventricular impairment. These results were compared with those obtained in a control population with isolated left anterior descending artery disease and either primary or secondary angina pectoris. We infer that the impairment of the right ventricle was related primarily to right ventricular ischemia and that left ventricular dysfunction alone did not cause an important depression of right ventricular systolic function. In conclusion, the clinical manifestations of RCA disease can be protean; the right ventricle can be the target of ischemia, and recognition of its impairment poses diagnostic problems. Radionuclide ventriculography and two-dimensional echocardiography, together with stressors of coronary flow reserve, are reliable techniques for assessing RCA-related ischemia.

Angina Pectoris

[Which programmable functions of pacemakers are available, and what is their clinical relevance?].

Microprocessors incorporated into cardiac pacemakers enable a substantial number of programmable functions (Table 1), the clinical relevance of which is the subject of this overview. Stimulation mode: The mode of operation can be chosen as fixed-rate, triggered and inhibited stimulation. Rate: Rate-programmability enables optimal setting with respect to electrophysiologic and hemodynamic considerations. Impulse amplitude and width: With programmable impulse amplitude and width excessive stimulation energy can be avoided and the duration of the aggregate prolonged. In some pacemakers, the output current can be chosen as "unregulated or regulated" whereby with regulated current the magnitude of the output impulse remains constant until the battery is depleted. Functional impairment of the pacemaker through threshold elevation or muscle stimulation can be eliminated by reprogramming of the impulse amplitude or width. Sensitivity: Programmability of the input sensitivity enables noninvasive counteraction of detection disturbances (as undersensing especially with low-amplitude atrial signals and oversensing of interference signals with subsequent pacemaker inhibition; Figure 1). A new option, automatic sensitivity setting, regulates the registration of cardiac activity at the atrial and/or ventricular level within a safety margin of 2:1; even though somewhat problematic, undersensing is rare. Electrode polarity: Depending on the clinical situation, the unipolar or bipolar electrode may offer advantages. The programmability of the electrode polarity accordingly represents a clinically-relevant new development which provides a favourable combination of bipolar detection and unipolar stimulation. Some modern dual-chamber systems enable separate programming of the atrial and ventricular electrode configurations. Hysteresis: For single-chamber systems and, more recently, AV-sequential pacemakers, hysteresis is optionally available, that is, a programmable prolongation of the basic interval after detection of a spontaneous cardiac event. With further refinement, the so-called search hysteresis prolongs the stimulation interval after a constant number of continuous stimulation cycles to a programmed hysteresis interval to allow spontaneous cardiac activity; if this is detected during the prolonged interval, the pacemaker is inhibited, otherwise the pacemaker stimulates at the set rate. An AV-interval hysteresis - to date only available in one pacemaker system - prolongs the duration of the AV-interval in the following cycles to a programmed interval, if, within the programmed AV-interval, spontaneous AV-conduction is detected. Additionally, after a defined number of AV-cycles an AV-interval prolongation is chosen to assess the possibility of physiologic AV-conduction. AV-interval: Modern AV-sequential pacemakers incorporate integration of the differential and rate-adaptive AV-interval.(ABSTRACT TRUNCATED AT 400 WORDS)

Algorithms

Clinical relevance of the interaction of theophylline with diltiazem or nifedipine.

The results of previously published studies indicate that calcium channel blockers are capable of competitively inhibiting cytochrome P-450 activity in hepatic microsomes, the pathway of theophylline metabolism. In addition, case reports have suggested that theophylline serum concentrations change when a calcium channel blocker has been added to or deleted from a stable theophylline regimen. To determine the clinical relevance of this potential interaction in patients with chronic asthma, we measured a peak steady-state theophylline serum concentration in 21 subjects while receiving theophylline alone (400 to 1,500 mg/day), and again, at least seven days later, after the addition of continuous therapy with maximally tolerated doses of either diltiazem (n = 18) or nifedipine (n = 16). The diltiazem dose was increased in 120 mg/day increments, as tolerated, to a maximum of 240 to 480 mg/day, while the nifedipine dose was increased in increments of 40 mg/day, to a maximum dose of 80 to 160 mg/day. The mean +/- SEM theophylline serum concentrations were 13.6 +/- 1.4 micrograms/ml before and 14.0 +/- 1.2 micrograms/ml during concurrent diltiazem therapy, and 12.6 +/- 1.0 micrograms/ml before and 12.2 +/- 1.1 micrograms/ml during nifedipine (p greater than 0.05). With this sample size there is a 5 percent chance that we missed a 20 percent change in serum concentration (type II error). Thus, maximum tolerated doses of diltiazem or nifedipine do not impair the metabolism of theophylline to a clinically relevant degree and adjustment of theophylline dosage is not required after the addition or discontinuation of diltiazem or nifedipine. In addition, these data suggest that currently available in vitro techniques for evaluating drug interactions in the hepatocyte do not predict the clinical relevance of such an interaction in patients who might require both drugs for different therapeutic indications.

Adolescent

Statistical significance versus clinical relevance. Part I. The essential role of the power of a statistical test.

When comparing two treatment groups, hypothesis testing is widely used. However, clinical trialists should be more interested in statistical methods which elicit the magnitude of the differences between treatment groups, rather than a simple indication of whether or not the differences are statistically significant. Statistical significance does not necessarily imply clinical relevance. If the true difference between two treatment groups is so small that it is clinically irrelevant, a sample size can be found for which this difference is statistically significant. On the other hand, if the difference between treatment groups is statistically non-significant, it may still be clinically important. The limitations of conventional hypothesis testing of equal true means as such are highlighted. The need to control the power of the test--which takes into account the difference in treatment means which is considered important (clinically relevant) by the researcher--is discussed.

Clinical Trials as Topic