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Biomedical subjects

A Oksenberg

Publications and source records attributed to A Oksenberg.

At least 19 recordsLinked to original sources
PubMed2001

Phasic activities of rapid eye movement sleep in vegetative state patients.

STUDY OBJECTIVES: To assess the phasic components of rapid eye movement (REM) sleep in patients in vegetative state and to evaluate the possible relationship of these activities to patient outcome. SETTING: Sleep disorders unit at a major rehabilitation hospital. DESIGN: Comparative control study. PATIENTS: Eleven patients in vegetative state (10 males and 1 female) aged 17-53 years. INTERVENTIONS: Continuous 24-hour polysomnographic recording. MEASUREMENTS AND RESULTS: All the patients had REM sleep periods during the 24-hr recording session. Mean total REM sleep time for the whole session was 66.5 +/- 34.9 min, and for the nocturnal hours only, 37.3 +/- 19.7 min. Comparison with the control group (79.2 +/- 11.5 min) yielded a significant difference only for nocturnal REM sleep time (p<0.0003). The duration of the REM sleep periods was significantly shorter in the patients than the controls for the whole 24-hr session (10.9 +/- 6.0 vs.19.6 +/- 4.9 min, p<0.008), but not for the nocturnal period alone. Compared to controls, the density of rapid eye movements (REMs) (p=0.001), chin twitches (p=0.002), and leg muscle twitches (p=0.023) was significantly lower in the patient group. The density of the sawtooth waves was also lower in the patients, but the difference did not reach significance (p=0.069). Similar results were obtained when the comparison was done only for the nocturnal period. There was no significant difference for any of the REM sleep characteristics or REM sleep phasic activities (24-hr, nocturnal and diurnal periods) between the patients who recovered consciousness and those who did not. CONCLUSIONS: The present study shows that patients in vegetative state have a significant reduction in the phasic activities of REM sleep. However, the amount of these activities is unrelated to recovery from the clinical condition. These findings may reflect possible damage to the pedunculopontine tegmentum cholinergic mechanisms in vegetative state.

Adolescent↗
PubMed2001

Are sleep-related breathing disorders important contributing factors to the production of essential hypertension?

About 50% of all patients with essential hypertension have obstructive sleep apnea (OSA), and another 40% of essential hypertension patients are habitual snorers, but without OSA. There is now convincing evidence that both OSA and habitual snoring are independent risk factors for essential hypertension, and that treatment of OSA will reduce the blood pressure. There is also some evidence that treatment of habitual snoring will also reduce the blood pressure. If this is the case, then we postulate a unifying hypothesis: that these two sleep-related breathing disorders (SRBD) (OSA and habitual snoring) are very common contributing factors to what is called "essential hypertension." The many epidemiologic, clinical, hematologic, biochemical, and physiologic findings seen in essential hypertension could also be due to the associated SRBD. A routine search for SRBD by asking a few simple questions of all patients (especially those with hypertension) and their bed partners could increase the number of patients detected and treated significantly. Successful treatment of SRBD would improve sleep quality and the associated excessive daytime sleepiness, and thus improve the quality of life. In addition, there is a good chance that the hypertension will improve as well.

Blood Pressure↗
PubMed2001

Apnoea characteristics across the night in severe obstructive sleep apnoea: influence of body posture.

Several studies have reported changes in apnoea characteristics across the night in patients with obstructive sleep apnoea (OSA). However, the effect of body posture on these changes has not been evaluated. The purpose of this study was to assess how body posture influences sleep apnoea characteristics across the night in severe OSA. Polysomnograms of 30 patients with severe OSA who had > or = 30 apnoeic episodes in the lateral position and 30 in the supine position during Stage 2 sleep, in the early, middle and late sleep periods were analysed. For each of the 30 events in each body position, the following variables were evaluated: apnoea duration; minimum saturation; change in saturation; duration of arousal; maximum snoring loudness and change in cardiac frequency. Although at any time during the night, apnoeas in the supine posture were more severe than those in the lateral position, a time effect across the night was found only for apnoea duration, change in cardiac frequency and duration of arousal. Body position did not affect the time trend for these variables across the night. The best fit for the changes of these three variables across the night was a quadratic time trend. It was concluded that in severe obstructive sleep apnoea during Stage 2 sleep, body position does not significantly affect the time trends of apnoea characteristics across the night. These data provide support for the participation of sleep-dependent mechanisms (homeostatic and circadian) in the determination of apnoea characteristics across the night.

Adult↗
PubMed2000

Sleep-related erections in vegetative state patients.

STUDY OBJECTIVES: To determine whether sleep-related erections occur in vegetative state and if so, to investigate their relationship with rapid eye movement (REM) sleep. DESIGN: N/A. SETTING: Major rehabilitation hospital. PATIENTS: Nine male patients in vegetative state aged 17-40 years. INTERVENTIONS: Continuous 24-hour polysomnographic recordings including penile circumferencial changes. MEASUREMENTS AND RESULTS: Sleep-related erection episodes (SREe's) were noted in all nine patients, ranging in number from 1-7/24 hr (average 4.4+2.4) and lasting 6 to 50 min (average 22.0+5.7 min). The number of REM periods (REMp's) ranged from 4-11 (average 6.6+2.5) and lasted for 1.0 to 44.0 min (average 16.0+6.6 min). Ninety-five percent of the SREe's recorded were associated with REMp's, usually (76.3%) appearing simultaneously with the REMp or soon thereafter; 64.6% of the REMp's were associated with SRE's. For both the nocturnal and diurnal periods, there were more REMp's with SREe's than without, and the REMp's associated with SREe's were of longer duration (by 25.5% and 28.4%, respectively). There were no statistically significant differences for any of the REMp or SREe parameters between the recovered and nonrecovered patients. CONCLUSIONS: The sleep-related erection characteristics of patients in vegetative state are similar to those of normal individuals. These findings may have implications for the assessment of the reorganization of REM sleep during recovery from vegetative state and may further help in our understanding of the pathophysiology of vegetative state. More studies are needed in larger groups of patients.

Adolescent↗
PubMed2000

Association of body position with severity of apneic events in patients with severe nonpositional obstructive sleep apnea.

STUDY OBJECTIVE: To compare the severity of sleep apneic events occurring in the supine posture vs the severity of sleep apneic events occurring in the lateral posture in patients with severe obstructive sleep apnea (OSA). DESIGN: A retrospective analysis of apneic event variables in a group of 30 OSA patients who underwent a complete polysomnographic evaluation in our sleep disorders unit. PATIENTS: Thirty patients with severe OSA (respiratory disturbance index [RDI] = 70.1+/-18.2) who were nonpositional patients (NPP), ie, in whom the ratio of the supine RDI to the lateral RDI is < 2 (supine RDI = 85.7+/-11.7, lateral RDI = 64.8+/-17.3), and who had > or =30 apneic events in the lateral position and 30 apneic events in the supine position during sleep stage 2 were included in the study. MEASUREMENTS: For the 30 apneic events in each body position, the following variables were evaluated: apnea duration (ApDur), minimum desaturation (MinDes), Delta desaturation (Delta-Des), duration of arousal (DurArous), maximum snoring loudness (MaxSL), and Delta heart rate (Delta-HR). In addition, three other variables assessed as a ratio of ApDur (Rate-D = Delta-Des/ApDur, R-HR =Delta-HR/ApDur, and R-Arous = DurArous/ApDur) were also calculated. RESULTS: For all variables evaluated, apneic events occurring in the supine posture were significantly more severe than those apneic events occurring in the lateral posture during sleep stage 2. ApDur of both body postures correlated significantly with DurArous, Delta-HR, and MaxSL, but not with Delta-Des and MinDes. ApDur correlated linearly with DurArous for both postures. The slopes of the two regression lines were similar (p = 0.578) but the regression line intercept for the supine apneas was significantly higher than that of lateral apneas (p<0.0001). In addition, the average number of supine apneic events that did not end with an arousal was smaller than the average number of lateral apneic events not ending with an arousal (4.4+/-6.0 vs. 10.5+/-6.7, respectively; p< 0.0001). Also, only 4 of 900 (0.44%) apneic events analyzed in the lateral posture ended with an awakening (> 15 s), whereas in the supine posture, there were 37 (4.1%) such events (p<0.001). CONCLUSIONS: These results show that even in patients with severe OSA who have a high number of apneic events in the supine and lateral posture, the apneic events occurring in the supine position are more severe than those occurring while sleeping in the lateral position. Thus, it is not only the number of apneic events that worsen in the supine sleep position but, probably no less important, the nature of the apneic events themselves.

Apnea↗
PubMed1999

The sleep supine position has a major effect on optimal nasal continuous positive airway pressure : relationship with rapid eye movements and non-rapid eye movements sleep, body mass index, respiratory disturbance index, and age.

STUDY OBJECTIVES: To evaluate the impact of sleep position on optimal nasal continuous positive airway pressure (nCPAP [op-nCPAP]) in obstructive sleep apnea (OSA) patients and to investigate how rapid eye movements (REM) and Non-REM (NREM) sleep, body mass index (BMI), respiratory disturbance index (RDI), and age are related to this effect. DESIGN: Retrospective analysis. SETTING: Sleep Disorders Unit at Loewenstein Hospital Rehabilitation Center. PATIENTS: Eighty-three consecutive adult OSA patients who underwent a complete nCPAP titration. From this group, 60 patients who spent at least 30 min in both the supine (Sup) and lateral (Lat) positions and 46 patients who had data on both positions during REM and NREM sleep were included in the analysis. RESULTS: In most OSA patients (52; 86.7%), the recommended op-nCPAP was obtained when the patients slept in the Sup posture. The mean op-nCPAP was significantly higher in the Sup posture (10.00 +/- 2.20 cm H(2)O) than it was in the Lat posture (7.61 +/- 2.69 cm H(2)O). The op-nCPAP was significantly higher in the Sup position than it was in the Lat position in both REM and NREM sleep, as well as in the severe BMI group (BMI >/= 30) and in the less obese group (BMI < 30). Similarly, in the severe (RDI >/= 40) and less severe groups (RDI < 40), as well as in both age groups (< and > 60 years of age), the op-nCPAP was significantly higher in the Sup posture than it was in the Lat posture. Irrespective of the four parameters mentioned, the actual differences in op-nCPAP between the two body postures were almost identical, ranging between 2.31 and 2.66 cm H(2)O. CONCLUSIONS: For most OSA patients, the op-nCPAP level is significantly higher in the Sup position than it is in the Lat position. This is true for REM and NREM sleep, for obese and nonobese patients, for patients with different degrees of severity, and for young and old OSA patients. Since the op-nCPAP was highest in the Sup posture during REM sleep, no nCPAP titration should be considered complete without the patient having slept in the Sup posture during REM sleep.

Adult↗
PubMed1998

REM sleep deprivation in monocularly occluded kittens reduces the size of cells in LGN monocular segment.

STUDY OBJECTIVES: In this study, we test the hypothesis that when REM-state activation (which impinges upon all lateral geniculate nucleus laminae irrespective of stimulating eye) is deprived, the monocular segment (MS) that is cut off from visual input and also deprived of REM-state activation will exhibit smaller cells, owing to the loss of extrinsic as well as intrinsic activation. DESIGN: We carried out a study comparing soma sizes in the MSs of kittens subjected to monocular deprivation (MD) + REM deprivation (RD) to two age-matched nonRD groups, MD ONLYs and MD MOMS (MD kittens living in their home cages). MEASUREMENTS AND RESULTS: Perikaryal outlines of 100 cells in each of the bilateral MSs were measured. As predicted, mean cell size in the MS connected to the patched eye of MD + RD kittens, but in neither of the control groups, was significantly smaller than in the MS afferented by the nonpatched eye. One-way ANOVAs comparing MS cell-size means from the same sides across groups were also significant, but the two MSs showed different results on post hoc tests. The ordering of MS cell-size means correlated significantly with a measure that aggregates the sources of activation reaching a particular MS and their durations. CONCLUSIONS: These results reveal that removal of REM-state activation during CNS development amplifies the plasticity processes generated when normal visual afferentation to central visual areas is interrupted. Our findings in the MS of the LGN indicate that during the usual operation of REM sleep, central visual-sensory sites receive intrinsic activation that, in the visual system, is additive and complementary to the stimulation obtained from extrinsic sources. In the course of early development, normative symmetrical activation of central visual areas during REM sleep may counterbalance plasticity changes caused either by absent or aberrant sensory stimulation.

Animals↗
PubMed1998

The effect of body posture on sleep-related breathing disorders: facts and therapeutic implications.

The aggravating effect of the supine body position on breathing abnormalities during sleep was recognized from the earliest studies on sleep breathing disorders. Most of the anatomical and physiological correlates of this phenomenon appear to be due to the effect of gravity on the upper airway. Although few articles have been published on this topic, it has been shown in a large population of obstructive sleep apnoea (OSA) patients that more than half of them are Positional Patients, i.e. they have at least twice as many apnoeas/hypopnoeas during sleep in the supine posture as in the lateral position. This positional phenomenon is influenced by factors such as Respiratory Disturbances Index (RDI), Body Mass Index (BMI), age and sleep stages. The sleep supine posture not only increases the frequency of the abnormal breathing events but also their severity. This sleep posture also has a detrimental effect on snoring, as well as on the optimal CPAP pressure. Positional Therapy, i.e. the avoidance of the supine posture during sleep, is a simple behavioural therapy for many mild to moderate OSA patients. Unfortunately, only a few studies, including only a few patients, have investigated this form of therapy. Although the results of these studies are promising, the lack of a reliable long-term evaluation of its efficacy is perhaps an important reason why this form of therapy has not been widely accepted. Since mild to moderate OSA patients are the majority of the OSA patients and since without treatment, a large percentage of them will develop a more severe form of the disease, a thorough evaluation with a major emphasis on the long-term effectiveness of this form of therapy is urgently needed.

Journal Article↗
PubMed1998

Oropharyngeal fatty infiltration in obstructive sleep apnea patients: a histologic study.

It has been suggested that due to fatty infiltration, obstructive sleep apnea (OSA) patients have a narrower pharyngeal airway than normal persons. To identify potential fatty infiltration of pharyngeal tissues that may contribute to OSA, a histologic study of the distal soft palate was performed. Histologic sections of 46 oropharyngeal specimens were evaluated. This included 25 overweight OSA patients (25/31), 6 normal-weight OSA patients (6/31), and a control group of 15 healthy (non-OSA) individuals. A semiquantitative analysis of the fatty tissue was performed. In all 31 OSA patients an excess of fatty infiltration was found in the histologic oropharyngeal specimens in comparison to the control group. No correlation was found between the pharyngeal fatty infiltration degree, the body mass index, and the apnea index. Irrespective of their body weight, in none of the patients without OSA was excessive fatty infiltration seen. It is suggested that excessive pharyngeal fatty infiltration plays a role in upper airway obstruction in OSA and that it can be associated with the development of apnea.

Adipose Tissue↗
PubMed1997

Sleep related breathing disorders are common contributing factors to the production of essential hypertension but are neglected, underdiagnosed, and undertreated.

There is now strong evidence from animal studies and, in humans, from epidemiological studies as well as from retrospective and prospective intervention studies, that obstructive sleep apnea (OSA) can cause persistent hypertension not only during sleep but during waking hours as well. There is also some evidence that habitual snoring alone, even without OSA, can do the same. Many of the hitherto unexplained epidemiological, clinical, biochemical, hematological, and physiological abnormalities seen in essential hypertension (EH) could be explained by the accompanying sleep related breathing disorders (SRBD). Many cases of resistant hypertension are probably due to SRBD. Recent studies show that SRBD are extremely common in EH but that the vast majority of patients with these sleep disorders are being missed by physicians who are treating the accompanying hypertension, even when the patients already have blatant symptoms of OSA. Recent investigations have shown that the probable reason for this underdiagnosis of OSA is lack of physician knowledge about the condition. This lack of knowledge is prevalent not only among family physicians, but among hypertension specialists and researchers in the field of hypertension as well. OSA is a common, easily diagnosed, and eminently treatable condition that is associated not only with disturbed sleep, loud snoring and excessive daytime sleepiness (which greatly increases the risk of traffic accidents), but also with hypertension, especially resistant hypertension, a broad range of cardiovascular problems, decreased sexual functioning, memory deficits, difficulty concentrating, and changes in personality and mood. It deserves much more attention by physicians treating hypertension than it is currently getting.

Animals↗
PubMed1997

Avoiding the supine position during sleep lowers 24 h blood pressure in obstructive sleep apnea (OSA) patients.

Obstructive sleep apnea (OSA), is a common clinical condition affecting at least 2-4% of the adult population. Hypertension is found in about half of all OSA patients, and about one-third of all patients with essential hypertension have OSA. There is growing evidence that successful treatment of OSA can reduce systemic blood pressure (BP). Body position appears to have an important influence on the incidence and severity of these sleep-related breathing disturbances. We have investigated the effect of avoiding the supine position during sleep for a 1 month period on systemic BP in 13 OSA patients (six hypertensives and seven normotensives) who by polysomnography (PSG) were found to have their sleep-related breathing disturbances mainly in the supine position. BP monitoring was performed by 24-h ambulatory BP measurements before and after a 1 month intervention period. We used a simple, inexpensive method for avoiding the supine posture during sleep, namely the tennis ball technique. Of the 13 patients, all had a reduction in 24-h mean BP (MBP). The mean 24-h systolic/diastolic (SBP/DBP) fell by 6.4/2.9 mm Hg, the mean awake SBP/DBP fell by 6.6/3.3 mm Hg and the mean sleeping SBP/DBP fell by 6.5/2.7 mm Hg, respectively. All these reductions were significant (at least P < 0.05) except for the sleeping DBP. The magnitude of the fall in SBP was significantly greater in the hypertensive than in the normotensive group for the 24 h period and for the awake hours. In addition, a significant reduction in BP variability and load were found. Since the majority of OSA patients have supine-related breathing abnormalities, and since about a third of all hypertensive patients have OSA, avoiding the supine position during sleep, if confirmed by future studies, could become a new non-pharmacological form of treatment for many hypertensive patients.

Adult↗
PubMed1997

Positional vs nonpositional obstructive sleep apnea patients: anthropomorphic, nocturnal polysomnographic, and multiple sleep latency test data.

STUDY OBJECTIVES: To compare anthropomorphic, nocturnal polysomnographic (PSG), and multiple sleep latency test (MSLT) data between positional (PP) and nonpositional (NPP) obstructive sleep apnea (OSA) patients. DESIGN: This is a retrospective analysis of anthropomorphic, PSG, and MSLT data of a large group of OSA patients who underwent a complete PSG evaluation in our sleep disorders unit. The patients were divided in two groups: the PP group, those patients who had a supine respiratory disturbance index (RDI) that was at least two times higher than the lateral RDI, and the NPP group, those patients in whom the RDI in the supine position was less than twice that in the lateral position. SUBJECTS: From a group of 666 consecutive OSA patients whose conditions were diagnosed in our unit from September 1990 to February 1995, 574 patients met the following criteria and were included in the study: RDI > 10; age > 20 years, and body mass index (BMI) > 20. RESULTS: Of all 574 patients, 55.9% were found to be positional. No differences in height were observed but weight and BMI were significantly higher in the NPP group, these patients being on the average 6.5 kg heavier than those in the PP group. The PP group was, on average, 2 years younger than the NPP group. Nocturnal sleep quality was better preserved in the PP group. In this group, sleep efficiency and the percentages of deep sleep (stages 3 and 4) were significantly higher while the percentages of light sleep (stages 1 and 2) were significantly lower than in the NPP group. No differences for rapid eye movement (REM) sleep were found. In addition, wakefulness after sleep onset and the number of short arousals (< 15 s) were significantly lower in the PP group. Apnea index and total RDI were significantly higher and the minimal arterial oxygen saturation in REM and non-REM sleep was significantly lower in the NPP. No differences in periodic limb movements data were found between the two groups. The average MSLT was significantly shorter in the NPP group. Univariate and multivariate stepwise logistic regression analysis showed that the most dominant variable that correlates with positional dependency in OSA patients is RDI, followed by BMI which also adds a significant contribution to the prediction of positional dependency. Age, although significant, adds only a minor improvement to the prediction of this positional dependency phenomenon. A severe, obese, and older OSA patient is significantly less likely to be positional than a mild-moderate, thin, and young OSA patient. In four obese OSA patients who lost weight, a much more pronounced reduction was seen in the lateral RDI than in the supine RDI, and three of these cases who were previously NPP became PP. CONCLUSIONS: In a large population of OSA patients, most were found to have at least twice as many apneas/hypopneas in the supine than in the lateral position. These so-called "positional patients" are on the average thinner and younger than "nonpositional patients." They had fewer and less severe breathing abnormalities than the NPP group. Consequently their nocturnal sleep quality was better preserved and, according to MSLT data, they were less sleepy during daytime hours. RDI was the most dominant factor that could predict the positional dependency followed by BMI and age. RDI showed a threshold effect, the prevalence of PP in those with severe RDI (RDI > or = 40) was significantly lower than in those OSA patients with mild-moderate RDI. BMI showed a major significant inverse relationship with positional dependency, while age had only a minor although significant inverse relationship with it. Body position during sleep has a profound effect on the frequency and severity of breathing abnormalities in OSA patients.

Adult↗
PubMed1997

Essential hypertension and abnormal upper airway resistance during sleep.

The epidemiological, clinical, hereditary, biochemical, hematological, and physiological characteristics of essential hypertension (EH) and obstructive sleep apnea (OSA) are reviewed here. This extensive review shows that essential hypertension and sleep-disordered breathing--independently of whether it is OSA syndrome or upper airway resistance syndrome--share strikingly similar characteristics. The accumulated data obtained by many different researchers support the hypothesis that EH is mainly due to increased upper airway resistance during sleep. If this hypothesis is correct, treating disorders that cause increased upper airway resistance, particularly during sleep, would be an important part of the treatment of essential hypertension.

Age Factors↗
PubMed1996

Rapid eye movement sleep deprivation in kittens amplifies LGN cell-size disparity induced by monocular deprivation.

The abundance of rapid eye movement (REM) sleep in the neonatal mammal and its subsequent decline in the course of development, as well as the dramatic and widespread enhancement of CNS activity during REM sleep, led us to propose that this state plays a functional role in the normative physiological and structural maturation of the brain [54]. When, after 1 week of monocular deprivation (MD), a second week of MD was coupled with behavioral deprivation of REM sleep, the structural alteration in the visual system provoked by MD alone (interlaminar relay cell-size disparity in the lateral geniculate nucleus (LGN) was amplified. With the addition of REM deprivation during MD, the LGN cells connected to the surgically patched eye, which are smaller than normal after MD, became even smaller, whereas the LGN cells receiving input from the seeing eye, which display compensatory hypertrophy after MD, grew even larger. We believe that the interlaminar disparity effect widened because during REM deprivation, the already vision-compromised LGN cells associated with the patched eye also lose the ascending brainstem activation reaching them during the REM state. Loss of the two main sources of 'afference' by these LGN cells permits their seeing-eye LGN counterparts to gain even greater advantage in the competition for synaptic connections in cortex, which is reflected in the relative soma sizes of the LGN relay cells. It is likely that the relatively abundant REM state in early maturation provides symmetric stimulation to all LGN relay cells, irrespective of eye of innervation. The symmetric activation propagated from brainstem to LGN acts to 'buffer' abnormal, asymmetric visual input and, thereby diminishes the extreme, asymmetric structural alteration that results from MD in the absence of REM sleep. We conclude that REM sleep-generated CNS discharge in development has the effect of 'protecting' the CNS against excessive plasticity changes. This is consistent with the possibility that REM sleep plays a role in the genetically programmed processes that direct normative brain development.

Animals↗
PubMed1996

Temporal variations of adenosine metabolism in human blood.

Eight diurnally active (06:00-23:00 h) subjects were adapted for 2 days to the room conditions where the experiments were performed. Blood sampling for adenosine metabolites and metabolizing enzymes was done hourly during the activity span and every 30 min during sleep. The results showed that adenosine and its catabolites (inosine, hypoxanthine, and uric acid), adenosine synthesizing (S-adenosylhomocysteine hydrolase and 5'-nucleotidase), degrading (adenosine deaminase) and nucleotide-forming (adenosine kinase) enzymes as well as adenine nucleotides (AMP, ADP, and ATP) undergo statistically significant fluctuations (ANOVA) during the 24 h. However, energy charge was invariable. Glucose and lactate chronograms were determined as metabolic indicators. The same data analyzed by the chi-square periodogram and Fourier series indicated ultradian oscillatory periods for all the metabolites and enzymatic activities determined, and 24-h oscillatory components for inosine, hypoxanthine, adenine nucleotides, glucose, and the activities of SAH-hydrolase, 5'-nucleotidase, and adenosine kinase. The single cosinor method showed significant oscillatory components exclusively for lactate. As a whole, these results suggest that adenosine metabolism may play a role as a biological oscillator coordinating and/or modulating the energy homeostasis and physiological status of erythrocytes in vivo and could be an important factor in the distribution of purine rings for the rest of the organism.

5'-Nucleotidase↗
PubMed1996

Essential and secondary hypertension and sleep-disordered breathing: a unifying hypothesis.

Obstructive sleep apnea (OSA) is a disorder in which there is repetitive collapse and closing of the pharynx during sleep. There is growing evidence to suggest that this disorder is a major cause of essential hypertension (EH) and that successful treatment of OSA can reduce the blood pressure (BP) significantly. In addition many other patients with EH have milder forms of sleep related breathing disorders (SRBD) like snoring, and upper airway resistance syndrome (UARS) which, while not as severe as OSA, may be severe enough to also cause systemic hypertension. We therefore propose a unifying hypothesis-that many patients with EH may have sleep related breathing disturbances (SRBD) and treatment of these disorders may improve the BP. SRBD could also explain many of the epidemiological, clinical, hereditary, biochemical, hematological and physiological characteristics seen in EH. In addition, many types of secondary hypertension (those caused by excessive alcohol intake, chronic renal failure, diabetes, hypothyroidism or acromegaly) have a higher than normal prevalence of OSA and OSA may contribute to the hypertension and organ damage found in these conditions as well. Thus SRBD may play an important role in the production of many cases of essential and secondary hypertension, and their early detection and treatment could reduce the hypertension and organ damage seen in these conditions.

Female↗