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Biomedical subjects

R N Melmed

Publications and source records attributed to R N Melmed.

At least 19 recordsLinked to original sources
PubMed2001

Treating hypertension with a device that slows and regularises breathing: a randomised, double-blind controlled study.

OBJECTIVE: To examine the efficacy of a new device, which slows and regularises breathing, as a non-pharmacological treatment of hypertension and thus to evaluate the contribution of breathing modulation in the blood pressure (BP) reduction. DESIGN AND SETTING: Randomised, double-blind controlled study, carried out in three urban family practice clinics in Israel. PATIENTS: Sixty-five male and female hypertensives, either receiving antihypertensive drug therapy or unmedicated. Four patients dropped out at the beginning of the study. INTERVENTION: Self treatment at home, 10 minutes daily for 8 consecutive weeks, using either the device (n = 32), which guides the user towards slow and regular breathing using musical sound patterns, or a Walkman, with which patients listened to quiet music (n = 29). Medication was unchanged 2 months prior to and during the study period. MAIN OUTCOME MEASURES: Systolic BP, diastolic BP and mean arterial pressure (MAP) changes from baseline. RESULTS: BP reduction in the device group was significantly greater than a predetermined 'clinically meaningful threshold' of 10.0, 5.0 and 6.7 mm Hg for the systolic BP, diastolic BP and MAP respectively (P = 0.035, P = 0.0002 and P = 0.001). Treatment with the device reduced systolic BP, diastolic BP and MAP by 15.2, 10.0 and 11.7 mm Hg respectively, as compared to 11.3, 5.6 and 7.5 mm Hg (P = 0.14, P = 0.008, P = 0.03) with the Walkman. Six months after treatment had stopped, diastolic BP reduction in the device group remained greater than the 'threshold' (P < 0.02) and also greater than in the walkman group (P = 0.001). CONCLUSIONS: The device was found to be efficacious in reducing high BP during 2 months of self-treatment by patients at home. Breathing pattern modification appears to be an important component in this reduction.

Adult↗
PubMed2001

Brain activity during biofeedback relaxation: a functional neuroimaging investigation.

The mechanisms by which cognitive processes influence states of bodily arousal are important for understanding the pathogenesis and maintenance of stress-related morbidity. We used PET to investigate cerebral activity relating to the cognitively driven modulation of sympathetic activity. Subjects were trained to perform a biofeedback relaxation exercise that reflected electrodermal activity and were subsequently scanned performing repetitions of four tasks: biofeedback relaxation, relaxation without biofeedback and two corresponding control conditions in which the subjects were instructed not to relax. Relaxation was associated with significant increases in left anterior cingulate and globus pallidus activity, whereas no significant increases in activity were associated with biofeedback compared with random feedback. The interaction between biofeedback and relaxation, highlighting activity unique to biofeedback relaxation, was associated with enhanced anterior cingulate and cerebellar vermal activity. These data implicate the anterior cingulate cortex in the intentional modulation of bodily arousal and suggest a functional neuroanatomy of how cognitive states are integrated with bodily responses. The findings have potential implications for a mechanistic account of how therapeutic interventions, such as relaxation training in stress-related disorders, mediate their effects.

Adult↗
PubMed1998

Psychological distress in patients with chronic, nonalcoholic, uncomplicated liver disease.

To study whether the presence of significant disease in a major organ, possibly with minimal or no clinical symptoms, would be associated with psychological disturbance, 80 subjects suffering from chronic hepatitis or cirrhosis, of nonalcoholic etiology were interviewed. Of these, 64 had either minimal or no physical symptoms. Patients completed the Brief Symptom Inventory (BSI) and the Impact of Event Scale (IES), questionnaires, which measure symptoms of psychological distress. It was found that 50% of the liver subjects were defined as cases by the BSI criteria including 15% who were defined as severe cases. There were no gender differences. Forty-five percent of asymptomatic liver subjects were defined as cases. Psychological distress was significantly pronounced in subjects with less than 12 years of education. This study points to a significant incidence of psychological distress, even in clinically asymptomatic subjects, suffering from chronic, nonalcoholic, uncomplicated liver disease.

Adult↗
PubMed1998

Recurrent hypoglycaemia in multiple myeloma: a case of Munchausen syndrome by proxy in an elderly patient.

A 73-year-old woman with multiple myeloma experienced four episodes of loss of consciousness, convulsions and profuse sweating whilst she was in the hospital. A thorough investigation in the department of medicine disclosed that with each attack, she had a serum glucose < 1.6 mM L-1, insulin level > 1400 pMol L-1 (N- < 150) and a normal level of serum C-peptide. Since she had no anti-insulin antibodies (which may rarely exist in multiple myeloma), a diagnosis of exogenous injection of insulin was made. A search for a possible perpetrator discovered that the patient had a daughter who was a surgical nurse and who was genuinely concerned whenever she was told that her mother was about to be discharged from the hospital. If she was the perpetrator in the present case, then it is possible that the motive for such an action was to postpone the mother's discharge from hospital. This case is an example of a 'factitious disease by proxy' in an elderly patient. The aim of the present report is to alert the medical personnel to the possibility that Munchausen's syndrome by proxy may also occur in the elderly.

Aged↗
PubMed1993

Post-traumatic stress disorder following medical events.

Four patients developed characteristic symptoms of post-traumatic stress disorder following medical and surgical events. Post-traumatic symptomatology was associated with poor recovery, a tendency to avoid further medical treatment and life-threatening behaviour. The authors provide clinical guidelines for the diagnosis of PTSD among patients whose medical conditions or treatment are highly stressful and discuss the need for prompt diagnosis and treatment of specific mental disorders among the medically ill.

Adult↗
PubMed1992

An improved method for endothelial cell seeding on polytetrafluoroethylene small caliber vascular grafts.

The creation of nonthrombogenic synthetic surfaces is a major challenge in biomedical research. The feature that clearly distinguishes natural blood vessels from their artificial counterparts is the presence of endothelial cell lining that besides being nonthrombogenic is capable of repair and renewal. This study describes a method of coating vascular grafts with a uniform, naturally produced subendothelial extracellular matrix before implantation. This substrate provides a most suitable bilayer for endothelial cell adhesion, growth, and differentiation, as compared with grafts coated with fibronectin or basement membrane extracts. It contains both adhesive glycoproteins (fibronectin, laminin, collagen) and proteoglycans (heparan sulfate) as well as endothelial cell growth factors (basic fibroblast growth factor) that support adhesion and normal growth of suboptimal concentrations of endothelial cells. We suggest that the presence in extracellular matrix of both adhesive macromolecules and potent endothelial cell-growth promoting factors will make the extracellular matrix a promising substrate for vascular grafts.

Animals↗
PubMed1991

[Vocal cord dysfunction mimicking bronchial asthma].

A 19-year-old woman presented with attacks of dyspnea, wheezing and stridor. She had been treated for bronchial asthma with bronchodilators and corticosteroids without improvement. During episodes of wheezing, lung function tests were consistent with variable extrathoracic obstruction. Fiberoptic bronchoscopy confirmed that wheezing was due to paradoxical adduction of the vocal cords during the respiratory cycle. Clinical symptoms improved with speech therapy and psychological aid in relaxation. Vocal cord dysfunction is important in the differential diagnosis of bronchial asthma.

Adult↗
PubMed1990

Symptom anticipation and the learned visceral response: a major neglected determinant of morbidity in functional and organic disorders.

This article explores the idea that symptoms in certain functional and organic disorders may be precipitated by a patient's anxiety in anticipation of that symptom's recurrence (symptom anticipation). Furthermore, through a process of learning from earlier experience, the induction of symptoms may be a highly directed process mediated by the nervous system and driven by the patient's apprehension or anxiety. In some patients this anticipation may be a major factor in causing a seemingly deteriorating clinical situation, which is often poorly responsive or unresponsive to conventional and perhaps previously effective medication. This situation tends to evoke a response from the treating physician that may lead to a course of action potentially dangerous to the patient through the use of more invasive diagnostic procedures, second-line drugs with more hazardous side effects, or even surgery. This article attempts to demonstrate that psychosomatic processes may be of considerable importance in mediating suffering through a defined mechanism in patients with established organic disease states.

Anxiety↗
PubMed1989

Serum neopterin changes in HIV-infected subjects: indicator of significant pathology, CD4 T cell changes, and the development of AIDS.

Serum neopterin is a metabolite of dihydroneopterin triphosphate, which is produced from GTP during immune activation. A study was undertaken in homosexual male subjects followed at 6 month intervals for 3 or more years to determine the value of serum neopterin changes induced by HIV infection. The significance of serum neopterin levels in evaluating prognosis of HIV-infected individuals was also assessed. Serum neopterin was found to be a useful indicator of the presence of HIV infection. Stratification of 29 HIV seroconverters showed a strong inverse correlation between the serum neopterin rise and the blood CD4 T cell fall in the first year following HIV infection. Thus, a small increase in neopterin (less than 5 nmol/L) at the time of HIV seroconversion was associated with minimal CD4 T cell reduction and a large increase (greater than 12 nmol/L) was associated with a much greater CD4 T cell fall. Neopterin levels were markedly different (lower) in individuals with little or no CD4 T cell fall when compared with those with moderate or marked rates of T cell fall. This relationship between serum neopterin and the CD4 T cell level was further confirmed by an evaluation of both parameters in a group of 799 seropositive homosexual men. In this analysis, serum neopterin was shown to have a significant predictive value for the development of AIDS within 3 years. Furthermore, when serum neopterin and CD4 T cell measurements were considered together, the prognostic value of the combination was significantly greater than either alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1988

Effect of hyperglycemia on pain perception and on efficacy of morphine analgesia in rats.

The effect exerted by different hyperglycemic states on the pain threshold and on the analgesic potential of morphine was studied in male Sabra rats with the hot plate device. Hyperglycemia induced by an intraperitoneal injection of 0.014 mol/kg glucose or an acute or chronic diabetic state induced by streptozocin injection did not significantly alter the pain threshold. However, states of acute and chronic diabetes markedly blunted the analgesic effect of morphine (5 mg/kg). Sabra rats maintained on a cocktail of glucose-saccharin, thought to activate the release of endogenous opioids, demonstrated an increased pain threshold and rapidly developed resistance to the analgesic effect of morphine. Previous studies have shown that glucose in high concentration may interfere with the interaction of morphine on the opiate receptor. The influence of the diabetic state on beta-endorphin synthesis and concentration in the central nervous system is another factor that might change pain perception in diabetes. We propose that in diabetes, generally, the pain threshold is adequately maintained, despite the antagonistic effect of glucose, partly due to a compensatory increased secretion of endogenous opioid peptides. We hypothesize that in patients with chronic painful diabetic neuropathy, these normal analgesic response mechanisms may be overwhelmed either by an excess of nociceptive impulses from diseased peripheral nerves or conceivably by a failure of endogenous opioid secretory response to the hyperglycemia.

Action Potentials↗
PubMed1988

Polymorphous drug eruption due to nifedipine.

A patient who underwent coronary bypass surgery and was treated with nifedipine subsequently developed an erysipelaslike erythematous itching plaque on both shins. Histopathologic examination of a biopsy specimen from the area showed findings compatible with a lichen-planus-like drug eruption. An awareness of varied skin reactions produced by nifedipine may reduce the suffering of patients and help prevent unnecessary local and general treatments.

Drug Eruptions↗
PubMed1986

The modulation of transcobalamin II (TC-II) production by cyclic adenosine 3',5'-monophosphate in the murine macrophage cell line J774: relationship to growth behavior.

We undertook a study to define the role of cyclic AMP [cAMP] in modulating the secretion of transcobalamin II (TC-II) in the mouse macrophage like cell line J774. J774 was observed to secrete large amounts of TC-II, particularly in the presence of 8-bromo cAMP or cholera toxin or when grown in medium supplemented with low concentrations of horse serum (1% or 5%) or in serum-free medium. Variant cell lines derived from J774 and deficient either in adenylate cyclase (ac -) or cAMP-dependent protein kinase (pk -) activity showed very low and intermediate levels of basal secretory activity of TC-II, respectively, compared to J774. Maximum secretory activity of TC-II was observed in J774 under conditions in which growth was poorest (in the presence of 8-bromo-cAMP or 1% or 5% horse serum-supplemented medium or in serum-free medium). Cells grown in serum-free medium were found to have elevated basal adenylate cyclase activity and cAMP levels compared to those grown in medium supplemented with 20% horse serum. The data from this study demonstrate a negative correlation between growth activity and TC-II secretion in the J774 cell line. The stimulatory effect of exogenous cAMP on TC-II secretion by J774, the reduced secretory activity of the variant lines ac- and pk- and the observed increase in cell cAMP levels under conditions of serum starvation in which TC-II secretion is considerably enhanced, suggest that cell cAMP is an important modulator of TC-II secretion and growth behavior in the J774 cell line.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1985

Basic characterization of an ouabain-resistant, bumetanide-sensitive K+ carrier-mediated transport system in J774.2 mouse macrophage-like cell line and in variants deficient in adenylate cyclase and cAMP-dependent protein kinase activities.

86Rb(K+) transport across the plasma membrane of macrophage-like cells was studied. The cells used were the wild-type J774.2 and its two variants, CT2 cells, deficient in adenylate cyclase, and J7H1 cells, deficient in cAMP-dependent protein kinase. In the three cell lines about 15% of the total 86Rb(K+) influx is transported by the K+ carrier-mediated transport system. The 86Rb(K+) efflux carried by the same transporter is negligible when measured in the absence of ouabain in the medium. Therefore this carrier conducts a net inward flux of K+ under the experimental conditions used. The transporter is sensitive to extracellular Na+ and inhibited by 'loop' diuretics; bumetanide inhibits ouabain-resistant 86Rb(K+) influx with IC50 of 0.1, 5.0, and 0.05 microM for J774.2, CT2 and J7H1 macrophages, respectively. The membrane potential of the three cells was measured, using the distribution of [3H]tetraphenylphosphonium [( 3H]TPP+) across the plasma membrane, and found to be -80.1, -108.5 and -105.1 mV for J774.2, CT2 and J7H1 cells, respectively. The addition of bumetanide to the cell medium does not alter [3H]TPP+ uptake indicating that the transporter is electrically silent. It is concluded that despite the differences in cAMP metabolism by the three macrophages, the basic characteristics of K+ carrier-mediated transport system of the three cells are very similar.

Adenylyl Cyclases↗