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Biomedical subjects

A Honig

Publications and source records attributed to A Honig.

At least 109 records · Page 6Linked to original sources
PubMed1984

Sustained suppression of voluntary sodium intake of spontaneously hypertensive rats (SHR) in hypobaric hypoxia.

Spontaneously hypertensive rats (SHR) of the Okamoto-Aoki-strain (n = 20) and normotensive rats (NCR) of a random-bred Wistar strain (n = 20) were kept in low-pressure chambers for 13 days at sea-level atmospheric pressure, then for 20 days at a simulated altitude of 4000 m, and subsequently again for 10 days at sea-level. The unrestrained animals were placed singly in metabolic cages and had free access to food, water, and a 2.5% NaC1-solution. Exposure to hypobaric hypoxia led to a transient decrease of daily food and water intake in both strains of animals and a slight reduction of saline consumption in the NCR. In contrast, the SHR showed a massive and sustained suppression of their voluntary intake of hypertonic saline throughout high-altitude exposure. Renal electrolyte and water excretion followed the reactions of salt and water intake. - In an additional series of experiments it was found that SH-rats react with a decrease of their systemic arterial blood pressures in hypobaric hypoxia only on condition that food and water but no additional salt is available to the animals. The data suggest that the antihypertensive effects of chronic high-altitude hypoxia depend both on the availability of salt and a reduction of salt appetite.

Altitude↗
PubMed1984

Influence of age on position, shape and size of the carotid bodies in spontaneously hypertensive (SHR) and normotensive (NCR) rats.

In normotensive Wistar rats (NCR) and spontaneously hypertensive rats (SHR) aging 3-6 d and 5-6, 15-20, 30-40 and 50-70 weeks respectively, position, shape and size of the carotid bodies were studied using ligh-microscopic methods. The anatomical position of the carotid bodies in the SHR was found to be less variable than in the NCR. In the hypertensive animals the glomera carotici were usually situated near the internal carotid artery. The carotid bodies of the NCR were of a more round-oval shape. In all age-groups the carotid bodies were compact and clearly demarked corpuscules. But also outside the principal mass of the glomera carotici small groups of type I cells were found in the surrounding nervous tissue or they appeared as miniglomera or periadventitial type I cells, respectively. These small groups of type I cells were predominantly provable in the 5-6 weeks old animals and more frequently in the NCR than in the SHR. The absolute carotid body volumes increased from birth up to an age of 30-40 weeks, whereas the relative carotid body volume, i.e. when related to the same body mass, became much smaller from birth up to an age of 15-20 weeks in both the normotensive and hypertensive animals. Except for the 5-6 weeks old group the SHR showed significantly greater carotid bodies when compared with the age-matched normotensive rats. In the course of aging in both strains of animals a stronger and more clearly developed interstitial fibrosis of the specific tissue of the carotid bodies occurred.

Aging↗
PubMed1984

Influence of age on carotid body size and arterial chemoreceptor reflex effects in spontaneously hypertensive (SHR) and normotensive rats.

In normotensive Wistar rats of a random-bred strain and in spontaneously hypertensive rats (SHR) of the Okamoto-Aoki-strain, the mean systemic arterial blood pressure, the pO2, pCO2, pH-values and the base excess of the arterial blood were measured during ventilating normal air as well as hypoxic (12.6% O2 in N2) and hyperoxic (100% O2) gas mixtures. The animals were anaesthetized and breathed spontaneously; they aged 5-6, 15-20, 30-40, and 50-70 weeks. The volume of their carotid bodies was determined morphometrically. When compared with the age-matched normotensive controls at an age of 5-6 weeks the SHR already exhibited slightly but significantly elevated blood pressures but had equal carotid body size and arterial carbon dioxide tension. In contrast, hypertensive animals in the established phase of hypertension (older than 15 weeks) showed greater carotid bodies and a highly significant respiratory alkalosis when compared with the corresponding age-group of the normotensive rats. The reactions of the mean systemic arterial blood pressure and the arterial pCO2 provoked by hypoxia and hyperoxia proved to be age-dependent in both the normotensive and hypertensive animals but this influence of age was different in the two strains of rats. The data support the concept that alterations of arterial chemoreceptor structures and reflex effects found in the established phase of hypertension are the result of this disease. Furthermore they indicate that, when interpreting arterial chemoreceptor reflex effects in hypertensive humans and animals, the stage of hypertension must be taken into account.

Aging↗
PubMed1981

The carotid bodies of spontaneously hypertensive rats (SHR): a functional and morphologic study.

The parameters of the acid-base-state of the arterial blood were measured in spontaneously hypertensive rats of the Okamoto-strain (SHR) and in normotensive Wistar rats (NWR) of a random-bred strain. The animals were anaesthetized with chloralose-urethane and breathed normal air under sea-level conditions. Structure and size of their carotid bodies were studied by light-microscopic methods. When compared with the NWR, the SHR showed a respiratory alkalosis and enlarged carotid bodies. In the SHR, never in the NWR, the lumen of the branches of the glomic arteries was narrowed by pad-like structures. The data suggest that systemic hypertension leads to morphologically and functionally detectable alterations of both carotid body structure and function. The interdependence of arterial chemoreceptor activity, sodium household, and the adjustment of systemic arterial blood pressure is briefly discussed.

Animals↗
PubMed1981

The carotid bodies in spontaneously hypertensive (SHR) and normotensive rats--a study concerning size, location and blood supply.

Size, anatomical position and blood supply of the carotid bodies were studied by light microscopic methods in spontaneously hypertensive rats of the Okamoto-strain (SHR) and in normotensive Wistar rats (NWR) of a random-bred strain. In both groups of animals the single carotid body was usually supplied by only one glomic artery which most frequently derived from the external carotid artery, more rarely from the occipital artery and very seldom from the internal carotid artery. In general the carotid bodies were of ellipsoide shape and compact structure and as a rule closely located to the internal carotid artery. In the NWR at the origins of their glomic arteries almost regularly circular intraarterial cushions were found; in the SHR such cushions were only seen in a few cases, and if so than they were less clearly developed. In the SHR, never in the NWR, within the carotid body the lumen of some branches of the glomic arteries was narrowed by pad-like structures. When compared with the NWR the SHR showed enlarged carotid bodies and a respiratory alcalosis, suggesting that systemic hypertension leads to morphologically and functionally detectable alterations of both carotid body structure and function.

Animals↗
PubMed1975

[Kidney function and arterial acid-base status during continuous stimulation of the carotid chemoreceptors in vagotomized cats].

In spontaneously breathing, chloralose narcotized and bilaterally vagotomized cats under mannite saline diuresis, the isolated carotid sinus were perfused for 1 hr with arterial and then for 1 hr with venous blood, and subsequently again with arterial blood for 1 hr. Either measure d or calculated were the parameters of arterial acid-base status, the arterial systemic bl-od pressure, the p-aminohippuric acid (PAH), inulin (IN), and osmolar clearance, the filtration fraction, the tubular reabsorption of oxmotically free water, the urinary time volume, and fractional excretions of the kidneys. Stimulation of the carotic chemoreceptors increased respiration, slightly enhanced the CPAH, and caused a minor fall of CIN with little altered filtration fraction. The renal resistance increased. The absolute and fractional excretions of urine, sodium, potassium, and of osmotically active particles rose significantly. Tubular reabsorption of osmotically free water showed a singificant increase. Urinary osmolarity remained constant in general. The changes of water and electrolyte excretion did not correlate with those of renal hemodynamics. The results argue against natriuresis being caused on chemoreceptor stimulation by increased filtrate volume of the whole kidney, or by decreased osmolarity of the renal medulla. The results are discussed with regard to the renal function in arterial oxygen deficiency.

Acid-Base Equilibrium↗
PubMed1975

[The function of innervated kidneys during stimulation of the carotid chemoreceptors under constant renal perfusion pressure].

The carotid chemoreceptors of narcotized, vagotomized and spontaneously breathing hydropenic cats in hypertonic mannite diuresis were stimulated by perfusion with venous blood penic cats in hypertonic mannite diuresis were stimulated by perfusion with venous blood for 70 min. Elevation of blood pressure at the innervated kidneys was prevented by an automatically controlled balloon located within the aorta. Stimulation of the chemoreceptors intensified respiration and raised the arterial systemic pressure. With the renal arteries at constant pressure, the effective renal plasma flow and the glomerular filtration rate significantly declined. The filtration fraction remained unchanged. The absolute urinary and sodium excretion did not change significantly, whereas the fractional time-volume, fractional sodium excretion, and the fractional osmotic excretion significantly increased. The fractional tubular reabsorption of osmotically free water was significantly enhanced. These reactions subsided during subsequent perfusion of the glomerula carotici with arterial blood. The results suggest that tubular sodium reabsorption is inhibited by stimulation of the carotid chemoreceptors, although re-adjustment of renal perfusion and filtrate volume cannot be excluded.

Absorption↗
PubMedDate not supplied

Effect of treatment of panic disorder in patients with frequent ICD discharges: a pilot study.

Anxiety and depression are common in patients receiving an implantable cardioverter defibrillator (ICD). An association between the number of ICD discharges and mood disturbances has been found. We performed a pilot study in ICD patients with frequent ICD shocks having a comorbid diagnosis of panic disorder with agoraphobia and depression, in which we treated them with a combination of a selective serotonin reuptake inhibitor (SSRI) and a behavior program. We hypothesized that this intervention would result in a decrease of ventricular premature beats or arrhythmias and possibly in a reduction of number of shocks. Four of 5 patients treated with such a combination therapy experienced no discharge of the ICD during a 6 month follow-up. The total number of ventricular premature beats decreased significantly after treatment. There was also clear psychiatric improvement. These results warrant larger scale studies on the pathophysiological mechanisms as well as treatment issues.

Aged↗
PubMedDate not supplied

Efficacy and safety of fluoxetine in the treatment of patients with major depression after first myocardial infarction: findings from a double-blind, placebo-controlled trial.

OBJECTIVE: Depression and hostility are significant risk factors for mortality and morbidity after myocardial infarction (MI). Much research is still needed to identify effective ways to reduce emotional distress in patients with cardiovascular disease. This double-blind, placebo-controlled study investigated the efficacy and safety of the antidepressant fluoxetine in patients with depression after their first MI. METHODS: Fifty-four patients with major depression after MI were randomly assigned to receive a flexible-dose regimen of fluoxetine or placebo for the first 9 weeks of a double-blind, placebo-controlled trial. Patients without serious adverse effects who wished to continue participating in the study were given fluoxetine or placebo for an additional 16 weeks. To evaluate the efficacy of fluoxetine, the 17-item Hamilton Depression Rating Scale (HAMD-17) and the Hostility Scale of the 90-item Symptom Check List (SCL-90) were used as primary measures of outcome. To evaluate the safety of fluoxetine, cardiac function was measured before and after treatment with echocardiography and electrocardiography. RESULTS: The a priori difference in antidepressive efficacy (4-point difference in HAMD-17 scores between the fluoxetine and placebo groups) was not met. However, the response rate among patients receiving fluoxetine was significantly greater than that among patients receiving placebo at week 25 (48 vs. 26%, p = .05). Among patients with mild depression (HAMD-17 score < or =21), HAMD-17 scores were significantly different (p < .05) between the fluoxetine and placebo groups at weeks 9 (by 5.4 points) and 25 (by 5.8 points). Also, hostility scores at week 25 were significantly reduced among patients receiving fluoxetine (p = .02). Analysis of electrocardiographic and echocardiographic parameters revealed no decrease in cardiac function as a result of treatment with fluoxetine. CONCLUSIONS: Although the overall difference between the fluoxetine and placebo groups was not significant, there was a trend favoring fluoxetine in this relatively small sample. The response rate in the group receiving fluoxetine was comparable with that observed in other studies of patients with cardiovascular disease. In addition, fluoxetine seemed to be particularly effective in patients with mild depression and was associated with a statistically significant reduction in hostility. The results of this study suggest that fluoxetine can be safely used to treat patients with post-MI depression beginning 3 months after the event.

Adult↗
PubMedDate not supplied

Sensitivity and specificity of observer and self-report questionnaires in major and minor depression following myocardial infarction.

This study evaluated screening abilities of self-report questionnaires for depression in first myocardial infarction (MI) patients. One month post-MI, 206 patients with first MI were screened for major and minor depression using the 90-item Symptom Check List (SCL-90), the Beck Depression Inventory (BDI), the Hospital Anxiety and Depression Scale (HADS), and the 17-item Hamilton Depression Rating Scale (Ham-D). The Structured Clinical Interview for DSM-IV criteria was used as the gold standard. Sensitivity and specificity for different cutoff points, using relative operating characteristics curves, were assessed. The internal consistency for all scales was good. When screening for major and minor depression, the optimal cutoff scores are lower than those for screening major depression only. The SCL-90, BDI, HADS, and Ham-D proved to have acceptable abilities for screening post-MI major and minor depression.

Adult↗
PubMedDate not supplied

Brain metastases in breast cancer--an in vitro study to evaluate new systemic chemotherapeutic options.

BACKGROUND: Fifteen-30% of breast cancer patients develop central nervous system (CNS) metastases. The most potent drugs for the treatment of breast cancer like taxanes, anthracyclines and trastuzumab have limited efficacy for brain metastases. No standardized therapy has yet been established for this condition. Drugs with proven efficacy in the CNS and which are commonly used for primary brain tumors were applied. We evaluated the capacity of these drugs to inhibit breast tumor cell growth in vitro. MATERIALS AND METHODS: Twelve primary cell cultures of pulmonary/pleural metastases of breast cancer and 3 commercially available cell lines were used for non-radioactive cytotoxicity assays to evaluate the efficacy of 3 different concentrations of Topotecan, Cisplatin, Nimustine, Vincristine, Irinothecan, Caelyx (pegylated liposomal Doxorubicin) and Etoposide. RESULTS: Topotecan, Cisplatin, Caelyx and Vincristine showed significantly higher cytostatic activity in vitro than Irinotecan, Etoposide and Nimustine. With regard to the median cytotoxicity, the order of drugs in our assays was Topotecan, Cisplatin, Vincristine, Caelyx, Irinotecan, Etoposide and Nimustine. Nimustine showed almost no efficacy against breast cancer cells. CONCLUSION: Topotecan, Cisplatin, Vincristine and Caelyx seem to be suitable candidates for further clinical evaluation. The data and the "liposomal packaging" suggest that Caelyx might be effective in the CNS. Since pulmonary metastases are often associated with brain metastases, evaluatingprimary cell cultures from malignant pleural effusions could be a valuable approach for the testing of new cytostatic drugs for brain metastases.

Adult↗