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PubMed1997

Patterns of neuronal firing in the human lateral thalamus during sleep and wakefulness.

The firing patterns of thalamic neurons in mammals undergo a dramatic change as the animal's state changes between sleep and wakefulness. During sleep the normal tonic firing of thalamic neurons changes into a slower bursting mode characterized by repetitive activation of a low-threshold calcium (Ca2+) current. The present report describes the patterns of thalamic neuronal firing during sleep and wakefulness in one human patient. Extracellular single neuron activity was recorded during functional stereotactic surgery in the thalamus of a patient with chronic pain, who was observed to fall asleep during the recording. Evolutive power spectra of the thalamic slow wave were used in place of cortical encephalography to confirm the patient's states of sleep and wakefulness. Twenty-nine sites were observed in motor and somatosensory thalamus (Vop, Vim, and Vc) that were characterized by the presence of neurons with bursting activity when the patient was asleep. Such bursting was not observed in the patient when she was awakened. At 14 of these sites we were able to discriminate the bursting activity of single units. In each case the cell stopped firing or its bursting was replaced by a tonic firing pattern when the patient was awakened. In three cases the patient began to lapse back into sleep and the neuron resumed firing in a bursting pattern once again. None of these units had a peripheral receptive field (RF), while several other units recorded in nearby regions that did not fire in a bursting pattern during sleep had kinesthetic or cutaneous RFs. Analysis of the intraburst firing pattern revealed increasing interspike intervals (ISI) for successive action potentials in a burst and that the duration of the first ISI in the burst decreased as the number of ISIs increased. This pattern is similar to that reported to occur as a result of a calcium spike. These data have confirmed for the first time that state-dependent changes in thalamic firing exist in the human and that the physiological substrates at the thalamic level that are involved in human sleep are similar to those observed in animals.

Adult↗

PubMed2004

Proteomic patterns as a diagnostic tool for early-stage cancer: a review of its progress to a clinically relevant tool.

The pace of development in novel technologies that promise improvements in the early diagnosis of disease is truly impressive. One such technology at the forefront of this revolution is mass spectrometry. New capabilities in mass spectrometry have provided the means for the development of proteomics, and the race is on to find innovative ways to apply this powerful technology to solving the problems faced in clinical medicine. One area that has garnered much attention over the past few years is the use of mass spectral patterns for cancer diagnostics. The use of these so-called 'proteomic patterns' for disease diagnosis relies fundamentally on the pattern of signals observed within a mass spectrum rather than the more conventional identification and quantitation of a biomarker such as in the case of cancer antigen-125- or prostate-specific antigen. The inherent throughput of proteomic pattern technology enables the analysis of hundreds of clinical samples per day. Currently, there are two primary means by which proteomic patterns can be acquired, surface-enhanced laser desorption/ionization (SELDI) and an electrospray ionization (ESI) method that has been popularized under the name, OvaCheck. In this review, an historical perspective on the development of proteomic patterns for the diagnosis of early-stage cancers is described. In addition, a critical assessment of the overall technology is presented with an emphasis on the steps required to enable proteomic pattern analysis to become a viable clinical tool for diagnosing early-stage cancers.

Early Diagnosis↗

PubMed1999

[Respiratory pattern and respiratory strain in automatic tube compensation and inspiratory pressure support].

STUDY OBJECTIVE: To investigate whether automatic tube compensation (ATC) or conventional pressure support (PS) is suitable to compensate for the work of breathing imposed by the breathing circuit without altering the breathing pattern. METHODS: Breathing pattern and work of breathing were measured in healthy volunteers. After a 20 min period of quiet breathing through a mouth piece (control) the volunteers were breathing through a 8.0 mm ID endotracheal tube (ETT) with four different settings: CPAP at 0 mbar, ATC, PS 5 mbar, PS 10 mbar. Each mode was applied for a 20 min period. At the end of each period data from 10 consecutive breaths were analyzed and averaged. Tidal volume (VT), breathing frequency (f), and minute ventilation (Ve) were determined from the stored gas flow tracings. Work of breathing was assessed as the pressure time product (PTP) calculated from the transdiaphragmatic pressure (Pdi) using a combined esophageal and gastric balloon catheter. RESULTS: During the control period the breathing pattern was as follows: VT = 882 +/- 277 ml, f = 13.7 +/- 5/min, Ve = 11.5 +/- 4.2 L/min. Maximal Pdi was 9.2 +/- 5.4 mbar and PTP was 11.3 +/- 7.1 mbar x s. Breathing CPAP through the ETT resulted in a slight increase in Pdi (10.8 +/- 5.4 mbar) and PTP (14.8 +/- 10.4 mbar x s) with an unchanged breathing pattern. However, for the same amount of unloading from respiratory workload ATC did not alter the breathing pattern, whereas PS 5 mbar and PS 10 mbar resulted in a clear increase in VT (1014 +/- 202 ml, 1336 +/- 305 ml, respectively). CONCLUSION: From the presented data in healthy volunteers it might be concluded that ATC and PS 5 mbar and 10 mbar are suitable modes for unloading the respiratory system from work imposed by the breathing circuit. ATC does not alter the breathing pattern in contrast to PS which results in an increased tidal volume. Therefore, the exact compensation of the work imposed by the ETT during ATC seems to be advantageous over ATC to assess the actual breathing pattern.

Adult↗

PubMed2006

A prospective study of dietary patterns, meat intake and the risk of gestational diabetes mellitus.

AIMS/HYPOTHESIS: The aim of this study was to prospectively examine whether dietary patterns are related to risk of gestational diabetes mellitus (GDM). METHODS: This prospective cohort study included 13,110 women who were free of cardiovascular disease, cancer, type 2 diabetes and history of GDM. Subjects completed a validated semi-quantitative food frequency questionnaire in 1991, and reported at least one singleton pregnancy between 1992 and 1998 in the Nurses' Health Study II. Two major dietary patterns (i.e. 'prudent' and 'Western') were identified through factor analysis. The prudent pattern was characterised by a high intake of fruit, green leafy vegetables, poultry and fish, whereas the Western pattern was characterised by high intake of red meat, processed meat, refined grain products, sweets, French fries and pizza. RESULTS: We documented 758 incident cases of GDM. After adjustment for age, parity, pre-pregnancy BMI and other covariates, the relative risk (RR) of GDM, comparing the highest with the lowest quintile of the Western pattern scores, was 1.63 (95% CI 1.20-2.21; p (trend)=0.001), whereas the RR comparing the lowest with the highest quintile of the prudent pattern scores was 1.39 (95% CI 1.08-1.80; p (trend)=0.018). The RR for each increment of one serving/day was 1.61 (95% CI 1.25-2.07) for red meat and 1.64 (95% CI 1.13-2.38) for processed meat. CONCLUSIONS/INTERPRETATION: These findings suggest that pre-pregnancy dietary patterns may affect women's risk of developing GDM. A diet high in red and processed meat was associated with a significantly elevated risk.

Adult↗

PubMed2003

Increased temporal patterns in choice responding and altered cognitive processes in schizophrenia and mania.

RATIONALE: The THEME method for measuring time-determined patterns (T-patterns) in behavior has been suggested as a new, more objective method for assessing cognitive disturbances in schizophrenia. OBJECTIVES: THEME was used to compare responses of schizophrenic patients with those having mood, schizoaffective, or severe anxiety disorders, and with healthy control subjects. METHODS: A two-choice, button-pressing task was used to elicit T-patterns among responses, with knowledge-of-results (K) rewards and coin reinforcements (RF) as reinforcers. Subjects were compared by diagnosis, drug treatment, and gender. RESULTS: Schizophrenic and manic patients showed excessive numbers of, and more complex T-patterns than controls. Schizophrenic and manic patients frequently demonstrated repetitive (stereotyped) responding, an effect never seen in healthy controls. Although clozapine (CLZ) reduced both excessive T-pattern structure and stereotyped responding, it also reduced growth of responding to the coin RF. CONCLUSIONS: Significant T-pattern increases may represent a common, time-related symptom of schizophrenia and mania. CLZ's effect on T-pattern production suggests that receptor effects other than the DAD(2) antagonism of "typical" neuroleptics' may be relevant to these findings.

Adult↗

PubMed2004

Primary synovial osteochondromatosis of the hip: extracapsular patterns of spread.

OBJECTIVE: To identify patterns of extracapsular extension of synovial osteochondromatosis of the hip. DESIGN AND PATIENTS: Seven cases of synovial osteochondromatosis of the hip were retrospectively reviewed. Imaging performed included conventional radiography ( n=7), arthrography ( n=1), CT ( n=3) and MR imaging ( n=3). Disease extent on imaging was assessed for each patient and the presence of intra-articular effusion, capsular abnormality and osteochondral bodies recorded. The presence and distribution of extra-articular spread was also assessed and correlated with the surgical findings. In all cases diagnosis was confirmed by biopsy, with all patients undergoing tumor resection with or without synovectomy. RESULTS: In five cases (5/7) disease extended beyond the hip capsule, while the remaining two cases (2/7) were confined to the hip joint. These findings were confirmed at surgery. Two distinct patterns of extracapsular spread were identified. The first pattern, noted in three cases, involved tumor extension along iliopsoas. The second pattern, noted in five cases, involved tumor extension along the obturator externus fat plane. In three cases both patterns were present. CONCLUSIONS: Extra-articular spread of synovial osteochondromatosis is common. Patterns of extra-articular spread may be predictable based on involvement of recognized periarticular bursae of the hip joint. Bursal patterns of extra-articular spread include extension into the iliopsoas bursa as well as communication along the obturator externus bursa of the hip.

Adult↗

PubMed2005

Analysis of different contrast enhancement patterns after microbubble-based contrast agent injection in liver hemangiomas with atypical appearance on baseline scan.

BACKGROUND: We describe different possible enhancement patterns in liver hemangiomas with atypical appearance on baseline ultrasound after microbubble-based contrast agent injection. METHODS: From a series of 253 consecutive lesions that were indeterminate on baseline ultrasound and then scanned after injection of air-filled microbubble contrast agent, 65 focal liver lesions were retrospectively selected on the basis of a diagnosis of liver hemangioma on multiphase contrast-enhanced computed tomography (n = 23), magnetic resonance imaging (n = 27), or histology (n = 15). Each lesion was scanned during arterial phase (30 s after microbubble injection) and late phase (5 min after injection). On-site sonologists performed retrospective assessment of contrast-enhancement patterns by consensus. RESULTS: Centripetal fill-in preceded (n = 50) or not preceded (n = 3) by peripheral nodular/rim-like enhancement was the prevalently observed contrast-enhancement pattern, equivalent to the typical enhancement pattern of liver hemangiomas on contrast-enhanced computed tomography or magnetic resonance imaging. In the remaining lesions, additional enhancement patterns (diffuse contrast enhancement with rapid fill-in and a late hyper-isoechoic appearance, n = 6; peripheral nodular enhancement with a late hypoechoic appearance, n = 3; or persistent heterogeneous and hyperechoic appearance, n = 3) were observed. CONCLUSION: Different contrast-enhancement patterns are possible in atypical liver hemangiomas after microbubble injection. Typical centripetal fill-in is the prevalent pattern and its evidence allows diagnosis.

Adult↗

PubMed2001

Pattern formation in discrete cell lattices.

In recent years, models for lattices of discrete cells have been attracting increased attention due to their greater flexibility to represent signalling and contact-dependent cell-cell interaction than conventional reaction-diffusion models. Using the almost forgotten method of Othmer and Scriven (1971) to calculate eigenvalues and eigenvectors for the Jacobian of the homogeneous state, a Turing-like linear stability analysis is carried out for diffusion-driven (DD) and signalling-driven (SD) discrete models. The method is a generalisation of the original method of Turing (1952). For two-species models it is found that there are profound differences between the two types of model when the size of the lattice increases. For DD models, the homogeneous state is typically either always stable, always unstable, or becomes unstable when the lattice gets suffficiently large. For SD models, the homogeneous state is typically unstable independent of lattice size, and stable only in a minor part of parameter space. Thus, SD models seem in general more pattern-prone than DD models. The conjecture that the linear analysis predicts the final pattern is investigated for a DD system with Thomas internal dynamics. Commonly the final pattern resembles the pattern of the initial perturbation of the homogeneous state, but this is by no means a general feature. When applied to a recent model for Delta-Notch lateral inhibition, linear analysis must be supplemented by various non-linear techniques to get a deeper insight into the patterning mechanisms. The overall conclusion is that a linear Turing analysis may be useful for predicting pattern, but when it comes to explaining patterns, non-linear analysis cannot be ignored.

Animals↗

PubMed2000

Multiple motor patterns in the stomatogastric ganglion of the shrimp Penaeus japonicus.

Motor patterns of the cardiac sac, the gastric and the pyloric network in the stomatogastric nervous system of the shrimp Penaeus japonicus, the most primitive decapod species, were studied. Single neurons can switch from the gastric or the pyloric pattern to the cardiac sac pattern. Some of the pyloric neurons fire with the gastric pattern. All of the gastric neurons fire with the pyloric pattern, unlike those in reptantians. Proctolin activates and modulates the cardiac sac and the pyloric rhythm, and promotes reconfiguration of the networks. Neurons of the three networks have so many interconnections that they construct a multifunctional neural network like those in Cancer. This network may function in different configurations under the appropriate conditions. Several modes of interactions between the networks found in different reptantian species can apply to the penaeidean shrimp. Such interactions are general features of the stomatogastric nervous system in decapods. Phylogenetic differences among the decapod infraorders are seen in the number and orientation of muscles and the innervation pattern of muscles. The multifunctional networks have existed in the most primitive decapod species, and types of configurations of the networks would have evolved to produce a wide range of motor patterns as the foregut structure has become complex.

Action Potentials↗

PubMed1998

Segment-specific retention of a larval neuromuscular system and its role in a new, rhythmic, pupal motor pattern in Manduca sexta.

At pupation in Manduca sexta, accessory planta retractor muscles and their motoneurons degenerate in segment-specific patterns. Accessory planta retractor muscles in abdominal segments 2 and 3 survive in reduced form through the pupal stage and degenerate after adult emergence. Electromyographic and electrophysiological recordings show that these accessory planta retractor muscles participate in a new, rhythmic 'pupal motor pattern' in which all four muscles contract synchronously at approximately 4 s intervals for extended bouts. Accessory planta retractor muscle contractions are driven by synaptic activation of accessory planta retractor motoneurons and are often accompanied by rhythmic activity in intersegmental muscles and spiracular closer muscles. The pupal motor pattern is influenced by descending neural input although isolated abdominal ganglia can produce a pupal motor pattern-like rhythm. The robust pupal motor pattern first seen after pupal ecdysis weakens during the second half of pupal life. Anemometric recordings indicate that the intersegmental muscle and spiracular closer muscle component of the pupal motor pattern produces ventilation. Accessory planta retractor muscle contractions lift the flexible abdominal floor, to which the developing wings and legs adhere tightly. We hypothesize that, by a bellows-like action, the accessory planta retractor muscle contractions circulate hemolymph in the appendages. Morphometric analysis shows that dendritic regression is similar in accessory planta retractor motoneurons with different pupal fates, and that accessory planta retractor motoneurons begin to participate in the pupal motor pattern while their dendrites are regressed.

Animals↗

PubMed2000

Butterfly wing pattern mutants: developmental heterochrony and co-ordinately regulated phenotypes.

Butterfly wings are colored late in development, when pigments are synthesized in specialized wing scale cells in a fixed developmental succession. In this succession, colored pigments are deposited first and the remaining areas are later melanized black or brown. Here we studied the developmental changes underlying two wing pattern mutants, firstly melanic mutants of the swallowtail Papilio glaucus, in which the yellow background is turned black, and secondly a Spotty mutant of the satyrid Bicyclus anynana, which carries two additional eyespots. Despite the very different pattern changes in these two mutants, they are both associated with changes in rates of scale development and correspondingly, the final color pattern. In the melanic swallowtail, background scales originally destined to become yellow (normally developing early and synthesizing papiliochrome) show delayed development, fail to make papiliochrome, and subsequently melanize at the same time as scales in the wild-type black pattern. In the B. anynana eyespot, scale maturation begins with the central white focus, then progresses to the surrounding gold ring and later finishes with melanization of the black center. Mutants showing additional eyespots display accelerated rates of scale development (corresponding to new eyespots) in wing cells not normally occupied by eyespots. Thus by either delaying or accelerating rates of scale development, the final color, or position, of a wing pattern element can be changed. We propose that this heterochrony of scale development is a basic mechanism of color pattern formation on which developmental mutants act to change lepidopteran color patterns.

Animals↗

PubMed2004

Proposal for two strategies to prevent remnants of gastric cancers after endoscopic mucosal resections: fluorescein electronic endoscopy and rapid stump diagnosis based on pit patterns.

BACKGROUND: The aim of the present study was to establish strategies to prevent cancer remnants after gastric endoscopic mucosal resection (EMR). METHODS: Whether surgical stumps could be diagnosed by pit patterns was examined on 38 well-fixed EMR materials. Furthermore, a rapid stump diagnostic method, which enables pit patterns of EMR material to be observed within 10 min, was developed. This rapid stump diagnosis was tested in 6 EMR cases of early gastric cancers, one of which was absolutely obscure to routine endoscopy. Fluorescein electronic endoscopy had been performed to reveal the extent of this cancer before EMR. RESULTS: Adenocarcinomas showed irregular pit patterns that were significantly different from those of normal gastric mucosae. Among the 38 cases, all 20 EMR materials that were diagnosed as stump (-) and 5 that were diagnosed as stump (+), based on pit patterns, were confirmed by tissue sections to be stump (-) and stump (+), respectively. Six of the 13 EMR materials diagnosed as stump (+/-) by pit patterns were finally diagnosed as stump (+) by tissue sections. These data indicate that cancer remnants could be avoided if the stumps were judged positive or suspiciously positive just after EMR, and additional resections were continuously done until the stumps became negative. Rapid stump diagnosis based on pit patterns was successful in all 6 tested cases. The extent of the early gastric cancer that was absolutely obscure to routine endocscopy was clearly and exactly revealed by fluorescein electronic endoscopies done before EMR and subsequent rapid stump diagnosis. CONCLUSION: It is probable that fluorescein electronic endoscopy, as a precise preoperative examination, and rapid stump diagnosis, based on pit patterns, will become effective strategies to prevent cancer remnants after EMR.

Adenocarcinoma↗

PubMed2002

Thoracic leg motoneurons in the isolated CNS of adult Manduca produce patterned activity in response to pilocarpine, which is distinct from that produced in larvae.

In the hawkmoth, Manduca sexta, thoracic leg motoneurons survive the degeneration of the larval leg muscles to innervate new muscles of the adult legs. The same motoneurons, therefore, participate in the very different modes of terrestrial locomotion that are used by larvae (crawling) and adults (walking). Consequently, changes in locomotor behavior may reflect changes in both the CNS and periphery. The present study was undertaken to determine whether motor patterns produced by the isolated CNS of adult Manduca, in the absence of sensory feedback, would resemble adult specific patterns of coordination. Pilocarpine, which evokes a fictive crawling motor pattern from the isolated larval CNS, also evoked robust patterned activity from leg motoneurons in the isolated adult CNS. As in the larva, levator and depressor motoneurons innervating the same leg were active in antiphase. Unlike fictive crawling, however, bursts of activity in levator or depressor motoneurons of one leg alternated with bursts in the homologous motoneurons innervating the opposite leg of the same segment and the leg on the same side in the adjacent segment. The most common mode of intersegmental activity generated by the isolated adult CNS resembled an alternating tripod gait, which is displayed, albeit infrequently, during walking in intact adult Manduca. A detailed analysis revealed specific differences between the patterned motor activity that is evoked from the isolated adult CNS and activity patterns observed during walking in intact animals, perhaps indicating an important role for sensory feedback. Nevertheless, the basic similarity to adult walking and clear distinctions from the larval fictive crawling pattern suggest that changes within the CNS contribute to alterations in locomotor activity during metamorphosis.

Action Potentials↗

PubMed2006

Organizing pneumonia: typical and atypical HRCT patterns.

Organizing pneumonia (OP) is a clinical-pathological entity that, if idiopathic, makes part of the idiopathic interstitial pneumonias classification of the American Thoracic Society/European Respiratory Society (ATS/ERS) of 2002 (50% of the cases, called cryptogenic organizing pneumonia, or COP). In the remaining 50% it is secondary, representing one modality of response of the lung to various forms of injury. Typical computed tomography (CT) pattern has been widely described and consists of peripheral parenchymal consolidations with air bronchogram with or without surrounding ground-glass-like opacities. The purpose of this article is to describe the less frequent imaging pattern of this disease represented by single or multiple focal lesions (nodules or masses that place diagnostic problems with malignancy), bronchocentric pattern (parenchymal consolidations with peribronchovascular distribution), atoll sign (central area of ground-glass-like density and peripheral area of consolidation), nodular lesions (poorly defined micronodular pattern), linear and band-like opacities (subpleural linear opacities that can have disposition parallel or perpendicular in relation to the pleura), perilobular pattern (thickening of the interlobular septa with reticular pattern) and progressive fibrotic pattern (irregular thickening of the interlobular septa with associated ground-glass-like appearance and consolidations).

Bronchography↗

PubMed1979

Abnormal septal motion in patients with postoperative right bundle branch block pattern.

Echocardiograms were performed on 25 patients with postoperative right bundle branch block pattern 3 to 93 months after surgery to assess the possible effects of abnormal cardiac excitation on septal motion. Each of the 25 patients demonstrated a unique pattern of septal motion characterized by the presence of an early systolic anterior septal notch, brief in duration and unrelated to subsequent systolic septal motion, right ventricular size, or surgical procedure. Beginning approximately 70 to 80 msec. after the initial QRS deflection, the septum abruptly moved anteriorly 2 to 7 mm. and then returned to a baseline position. The total duration of this abnormal septal motion lasted 78 to 155 msec. This echocardiographic pattern was not seen in any of 30 patients in two control groups. Twenty had a normal QRS pattern and ten demonstrated right ventricular hypertrophy. In addition, patients who underwent open heart surgery and had normal right ventricular conduction postoperatively did not show this echocardiographic pattern with either normal or paradoxical septal motion. This previously undescribed echocardiographic pattern demonstrates that septal motion is uniquely affected in patients with postoperative right bundle branch block pattern.

Adolescent↗

PubMed1985

Peripheral influences on the central pattern-rhythm generator for tongue movements in the rat.

Rhythmic activity in the tongue and other oral muscles was evoked by mechanical stimulation of the hard palate in ketamine-anaesthetized rats. The relation between neural discharges of single hypoglossal motoneurones and activity in the masseter and anterior digastric muscle, and stimulus parameters was analysed. By varying the stimulus parameters, hypoglossal-motoneurone activity was modulated from phasic reflex activity into rhythmic activity. The tongue and other recorded muscles are likely to be controlled by the same pattern-rhythm generator, when rhythmic activity is induced by palatal stimulation. Exteroceptive oral stimuli can activate the tongue pattern-rhythm generator independently of proprioceptive feedback. Proprioceptive input from oral structures influenced the burst duration of rhythmic hypoglossal motoneurone activity. The cycle duration and the number of discharges/burst, however, was not affected by proprioceptive input. The hypoglossal-motoneurone pool may be influenced by more than one pattern-rhythm generator because the burst characteristics of rhythmically-firing hypoglossal motoneurones depend upon stimulus conditions. These hypoglossal pattern-rhythm generators have possible hierarchic relations because a shift from one burst pattern into another can be evoked by changing stimulus conditions. The pattern-rhythm generators for oral movements may be composed of a neural-pattern generator and a neural-rhythm generator, which can be modulated separately by peripheral inputs.

Action Potentials↗

PubMed1983

The effect of neonatal testosterone on specific male and female patterns of phosphorylated cytosolic proteins in the rat preoptic-hypothalamus, cortex and amygdala.

This study demonstrates that in the rat there are specific patterns of in vitro phosphorylation of cytosolic proteins for the preoptic-hypothalamus, cortex, and amygdala. Furthermore, there are sex-specific patterns for the male and female preoptic-hypothalamus. These sex-specific patterns are controlled by the sex steroid environment of the neonatal rat. If testosterone was removed by neonatal castration of a male, the female pattern of in vitro phosphorylated proteins was found in the adult preoptic-hypothalamus. Conversely, if a neonatal female was androgenized at 2 days by a single injection of testosterone, a male-like pattern was found in the adult preoptic-hypothalamus. Treatment of neonatal females or males did not alter the adult patterns of in vitro protein phosphorylation in the cortex, but such treatments did give rise to anomalous patterns in the amygdala. Thus, as with behavioral and structural characteristics of the preoptic-hypothalamus, the spectrum of phosphorylated proteins in this region also seems to be organized by neonatal testosterone.

Amygdala↗

PubMed1989

A multicentred phase III comparative study of two hormonal contraceptive preparations given once-a-month by intramuscular injection. II. The comparison of bleeding patterns. World Health Organization Task Force on Long-Acting Systemic Agents for Fertility Regulation.

A multicentred Phase III clinical trial was conducted in 12 countries to compare HRP112 (depot-medroxyprogesterone acetate, 25 mg and estradiol cypionate, 5 mg) and HRP102 (norethisterone enantate, 50 mg and estradiol valerate, 5 mg) given every 28 days. Contraceptive efficacy and side-effects of both regimens were reported previously. Their effect on vaginal bleeding patterns is the object of this paper. A total of 2320 women were randomly assigned to each drug and 2000 of them provided a menstrual diary. The comparison of the bleeding patterns is made using a 90-day reference period approach and following the guidelines published by WHO. The analysis failed to identify any major difference in the vaginal bleeding patterns induced by both contraceptive preparations. For both drugs, the first bleeding episode following the first injection occurs early. For 70% of users, this is followed by a regular vaginal bleeding pattern similar to an untreated pattern. Others experience irregular bleeding and a few have either infrequent or frequent bleeding. The extremes of amenorrhea and prolonged bleeding are rare. There are no major trends in vaginal bleeding patterns with prolonged use of either preparation. Women with the worst vaginal bleeding patterns discontinue early in the clinical trial and the last three months of experience have the most influence in their decision to stop using the contraceptive method. The analysis suggests how the life-table analysis of discontinuation reasons underestimates the true incidence of vaginal bleeding irregularities in a clinical trial.

Amenorrhea↗