Carmustine (BCNU) plus Teniposide (VM26) in recurrent malignant glioma

BACKGROUND

After the failure of radiotherapy and temozolomide, there is no established standard therapy for patients with recurrent glioblastoma (GBM). Based on the promising data of a previous trial (NOA-01) for primary GBM and some retrospective case series for GBM recurrence, the combination of nimustine and teniposide (VM26) was commonly used in this setting. When nimustine was no longer available in Europe, we switched to intrvaveneous carmustine (BCNU). Data on the toxicity and efficacy of BCNU and VM26 in recurrent GBM are lacking.

METHODS

In our neurooncological center, all patients with recurrent GBM or with progressed glioma and a typical MRI lesion suggesting GBM treated with BCNU (130-150 mg/m(2), day 1/42) and VM26 (45-60 mg/m(2), days 1-3/42) were analyzed retrospectively for progression-free survival, overall survival and toxicity.

RESULTS

Fifteen patients (median age 52 years) were identified. Median progression-free survival was 2 months and median overall survival was 4 months. Two patients (14%) developed grade 3/4 hematotoxicity. Nonhematological toxicity ≥grade 3 was not observed.

CONCLUSION

Our data do not support the application of BCNU/VM26 in patients with late stages of recurrent GBM.

FLAIR-only progression in bevacizumab-treated relapsing glioblastoma does not predict short survival

OBJECTIVES

In this study, we analyzed the prognostic value of different MRI progression patterns for survival in patients with recurrent malignant glioma treated with the vascular endothelial growth factor antibody bevacizumab.

PATIENTS AND METHODS

Twenty-six adult patients with recurrent malignant glioma treated with bevacizumab or bevacizumab/irinotecan were retrospectively analyzed for the development of contrast-enhanced (T1-weighted MRI) and T2/FLAIR lesions. According to the progression pattern, patients were divided into 3 subgroups: (1) patients with primarily progressive contrast-enhanced lesions in the first MRI after initiation of therapy ('primary PD group'); (2) patients with stable or regressive enhanced lesions but progressive FLAIR lesions ('FLAIR-only PD group'), and (3) patients with stable or regressive contrast-enhanced T1 and FLAIR lesions ('no PD group').

RESULTS

Overall survival (OS) in the 6 patients in the FLAIR-only PD group was not significantly different from the 11 patients in the no PD group (median 311 vs. 254 days, respectively). In contrast, survival in the FLAIR-only PD group was significantly better (p = 0.025) than in the primary PD group.

CONCLUSION

FLAIR-only progression is not an independent prognostic factor negatively influencing OS in recurrent glioblastoma treated with bevacizumab and should not lead to discontinuation of bevacizumab therapy.

Aquaporin-4 antibody negative recurrent isolated optic neuritis: clinical evidence for disease heterogeneity

Recurrent optic neuritis is frequently observed in multiple sclerosis (MS) and is a typical finding in neuromyelitis optica (NMO). Patients that lack further evidence of demyelinating disease are diagnosed with RION (recurrent isolated optic neuritis) or CRION (chronic relapsing inflammatory neuropathy) if they require immunosuppressive therapy to prevent further relapses. The etiology and disease course of this rare condition are not well defined. We studied a series of 10 patients who presented with recurrent episodes of isolated optic neuritis (ON, n=57) and were followed over a median of 3.5 years. Visual acuity was severely reduced at the nadir of the disease (20/200 to 20/800). All patients had MRI non-diagnostic for MS/NMO and were aquaporin-4 antibody negative. Six patients fulfilled the CRION criteria. In two of these a single ON followed by a long disease-free interval preceded development of CRION for years, suggesting the conversion of an initially "benign" isolated ON into the chronic relapsing course. Cerebrospinal fluid (CSF) analysis revealed mild pleocytosis in 5 patients, identical oligoclonal bands in serum and CSF were observed in 2 patients, while the others remained negative. In conclusion, recurrent ON is a disease entity that requires aggressive glucocorticoid and eventually long-term immunosuppressive therapy to prevent substantial visual impairment.

Chronic homocysteine exposure causes changes in the intrinsic electrophysiological properties of cultured hippocampal neurons

Homocystinuria is an inborn error of metabolism characterized by plasma homocysteine levels up to 500 μM, premature vascular events and mental retardation. Mild elevations of homocysteine plasma levels up to 25 μM, which are common in the general population, are associated with vascular disease, cognitive impairment and neurodegeneration. Several mechanisms of homocysteine neurotoxicity have been investigated. However, information on putative effects of hyperhomocysteinemia on the electrophysiology of neurons is limited. To screen for such effects, we examined primary cultures of mouse hippocampal neurons with the whole-cell patch-clamp technique. Homocysteine was applied intracellularly (100 μM), or cell cultures were incubated with 100 μM homocysteine for 24 h. Membrane voltage was measured in current-clamp mode, and action potential firing was induced with short and prolonged current injections. Single action potentials induced by short current injections (5 ms) were not altered by acute application or incubation of homocysteine. When we elicited trains of action potentials with prolonged current injections (200 ms), a broadening of action potentials during repetitive firing was observed in control neurons. This spike broadening was unaltered by acute application of homocysteine. However, it was significantly diminished when incubation with homocysteine was extended to 24 h prior to recording. Furthermore, the number of action potentials elicited by low current injections was reduced after long-term incubation with homocysteine, but not by the acute application. After 24 h of homocysteine incubation, the input resistance was reduced which might have contributed to the observed alterations in membrane excitability. We conclude that homocysteine exposure causes changes in the intrinsic electrophysiological properties of cultured hippocampal neurons as a mechanism of neurological symptoms of hyperhomocysteinemia.

Transcriptional regulation of T-type calcium channel CaV3.2: bi-directionality by early growth response 1 (Egr1) and repressor element 1 (RE-1) protein-silencing transcription factor (REST)

The pore-forming Ca(2+) channel subunit Ca(V)3.2 mediates a low voltage-activated (T-type) Ca(2+) current (I(CaT)) that contributes pivotally to neuronal and cardiac pacemaker activity. Despite the importance of tightly regulated Ca(V)3.2 levels, the mechanisms regulating its transcriptional dynamics are not well understood. Here, we have identified two key factors that up- and down-regulate the expression of the gene encoding Ca(V)3.2 (Cacna1h). First, we determined the promoter region and observed several stimulatory and inhibitory clusters. Furthermore, we found binding sites for the transcription factor early growth response 1 (Egr1/Zif268/Krox-24) to be highly overrepresented within the Ca(V)3.2 promoter region. mRNA expression analyses and dual-luciferase promoter assays revealed that the Ca(V)3.2 promoter was strongly activated by Egr1 overexpression in vitro and in vivo. Subsequent chromatin immunoprecipitation assays in NG108-15 cells and mouse hippocampi confirmed specific Egr1 binding to the Ca(V)3.2 promoter. Congruently, whole-cell I(CaT) values were significantly larger after Egr1 overexpression. Intriguingly, Egr1-induced activation of the Ca(V)3.2 promoter was effectively counteracted by the repressor element 1-silencing transcription factor (REST). Thus, Egr1 and REST can bi-directionally regulate Ca(V)3.2 promoter activity and mRNA expression and, hence, the size of I(CaT). This mechanism has critical implications for the regulation of neuronal and cardiac Ca(2+) homeostasis under physiological conditions and in episodic disorders such as arrhythmias and epilepsy.

Development and validation of a decision-making algorithm to guide the use of plerixafor for autologous hematopoietic stem cell mobilization

Plerixafor is an inhibitor of CXCR-4 (CXC chemokine receptor-4)/SDF (stromal cell-derived factor)-1 binding used in combination with granulocyte colony-stimulating factor (G-CSF) for mobilization of autologous peripheral blood hematopoietic stem cells (HSCs). We developed a data-generated, cost-saving decision-making algorithm that uses the CD34+ count in the peripheral blood on the fourth day of G-CSF administration (PB-CD34+), and the collection target (T-CD34+) to decide between continuing G-CSF only (G approach) or adding plerixafor to the mobilization regimen (G+P approach) aiming at the lowest cost. The G+P approach was more cost-effective with lower PB-CD34+. It was possible to determine, for each T-CD34+, the maximum PB-CD34+ for which the G+P approach is cost-effective, generating an algorithm for the use of plerixafor. We validated this algorithm in a cohort of 34 patients undergoing HSC mobilization. In all, 11 patients completed collection on the G approach and 23 patients on the G+P approach, with 91% of the patients completing collection within the predicted number of apheresis sessions. All patients who underwent transplantation engrafted with minimal differences in engraftment time between G and G+P approaches. This validated algorithm provides a potential cost-saving decision tool for the use of plerixafor in autologous HSC mobilization.

Diminished response of CA1 neurons to antiepileptic drugs in chronic epilepsy

PURPOSE

A substantial proportion of epilepsy patients ( approximately 30%) continue to have seizures despite carefully optimized treatment with antiepileptic drugs (AEDs). One key concept to explain the development of pharmacoresistance is that epilepsy-related changes in the properties of CNS drug targets result in AED-insensitivity of these targets. These changes then contribute to drug-resistance on a clinical level. We have tested this hypothesis in hippocampal CA1 neurons in experimental epilepsy.

METHODS

Using patch-clamp techniques, we thoroughly examined the effects of carbamazepine (CBZ) and phenytoin (PHT) on voltage-gated Na(+) currents (I(Na)) in hippocampal CA1 neurons of sham-control and chronically epileptic rats.

RESULTS

We find that there were significant changes in the effects of PHT, but not CBZ on the voltage-dependence of inactivation, resulting in a significant reduction in voltage-dependent blocking effects in chronically epileptic animals. Conversely, CBZ effects on the time course of recovery from inactivation of I(Na) were significantly less pronounced in epileptic compared to sham-control animals, whereas PHT effects remained unaltered.

CONCLUSIONS

Our findings indicate that AED-sensitivity of Na(+) currents is reduced in chronic epilepsy. The reduction in sensitivity is due to different biophysical mechanisms for CBZ and PHT. Furthermore, comparison to published work suggests that the loss of AED-sensitivity is less pronounced in CA1 neurons than in dentate granule neurons. Thus, these results suggest that target mechanisms of drug resistance are cell type and AED specific. Unraveling these complex mechanisms is likely to be important for a better understanding of the cellular basis of drug-resistant epilepsy.

Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): Standardized protocol and reference values

The nationwide multicenter trials of the German Research Network on Neuropathic Pain (DFNS) aim to characterize the somatosensory phenotype of patients with neuropathic pain. For this purpose, we have implemented a standardized quantitative sensory testing (QST) protocol giving a complete profile for one region within 30 min. To judge plus or minus signs in patients we have now established age- and gender-matched absolute and relative QST reference values from 180 healthy subjects, assessed bilaterally over face, hand and foot. We determined thermal detection and pain thresholds including a test for paradoxical heat sensations, mechanical detection thresholds to von Frey filaments and a 64 Hz tuning fork, mechanical pain thresholds to pinprick stimuli and blunt pressure, stimulus/response-functions for pinprick and dynamic mechanical allodynia, and pain summation (wind-up ratio). QST parameters were region specific and age dependent. Pain thresholds were significantly lower in women than men. Detection thresholds were generally independent of gender. Reference data were normalized to the specific group means and variances (region, age, gender) by calculating z-scores. Due to confidence limits close to the respective limits of the possible data range, heat hypoalgesia, cold hypoalgesia, and mechanical hyperesthesia can hardly be diagnosed. Nevertheless, these parameters can be used for group comparisons. Sensitivity is enhanced by side-to-side comparisons by a factor ranging from 1.1 to 2.5. Relative comparisons across body regions do not offer advantages over absolute reference values. Application of this standardized QST protocol in patients and human surrogate models will allow to infer underlying mechanisms from somatosensory phenotypes.

T-type Ca2+ channels encode prior neuronal activity as modulated recovery rates

T-type Ca2+ channels give rise to low-threshold inward currents that are central determinants of neuronal excitability. The availability of T-type Ca2+ channels is strongly influenced by voltage-dependent inactivation and recovery from inactivation. Here, we show that native and cloned T-type Ca2+ channel subunits selectively encode specific aspects of prior membrane potential changes via a powerful modulation of the rates with which these channels recover from inactivation. Increasing the duration of subthreshold (-70 to -55 mV) conditioning depolarizations caused a pronounced slowing of subsequent recovery from inactivation of both cloned (Ca(v)3.1-3.3) and native T-type channels (thalamic neurones). The scaling of recovery rates with increasing duration of conditioning depolarizations could be well described by a power law function. Different T-type channel isoforms exhibited overlapping but complementary ranges of recovery rates. Intriguingly, scaling of recovery rates was dramatically reduced in Ca(v)3.2 and Ca(v)3.3, but not Ca(v)3.1 subunits, when mock action potentials were superimposed on conditioning depolarizations. Our results suggest that different T-type channel subunits exhibit dramatic differences in scaling relationships, in addition to well-described differences in other biophysical properties. Furthermore, the availability of T-type channels is powerfully modulated over time, depending on the patterns of prior activity that these channels have encountered. These data provide a novel mechanism for cellular short-term plasticity on the millisecond to second time scale that relies on biophysical properties of specific T-type Ca2+ channel subunits.

Überschätzen Ärzte die Effekte der Akupunkturbehandlung?

BACKGROUND

Physicians' ratings about their patients' pain prove to be invalid compared to patients' ratings. This is especially true if pain rating acts as an indicator for therapy outcome. The aim of this study was to compare physicians' and patients' ratings of pain relief following acupuncture and to identify correlations between patient characteristics and potential miscalibrations.

PATIENTS AND METHODS

In a cross-sectional study 291 pain patients with gonarthrosis or chronic low back pain and their attending physicians were asked to give their rating of patients' pain relief following acupuncture. Patients were interviewed by telephone, and doctors responded to questionnaires.

RESULTS

The proportion of false-positive physicians' ratings was 81% referring to patients without self-reported benefit from acupuncture. Just every fifth patient without pain relief was correctly classified by his physician. There was no correlation between patients' characteristics and false-positive ratings of physicians.

CONCLUSIONS

Evaluation of treatment in daily medical routine should be primarily based on information provided by patients.

Langfristige Effekte von Opioiden bei Patienten mit chronischen nicht-tumorbedingten Schmerzen

A total of 121 patients with at least a 3-year history of opioid use were evaluated by a standardized interview during a clinical visit or telephone call. Assessed items were the present and former drug medication, daily doses, withdrawals, contentment with the treatment, positive/negative treatment effects, average/maximum pain and others.

STATISTICS

chi(2), ANCOVA and survival analysis. Of 121 patients (frequency of withdrawal 14.8% mainly due to lack of efficacy) with an average treatment time of 66 months (37-105 months; 80,264 days; 87% more than 5 years), 103 (85%) still took an opioid step II or III according to the WHO analgesic ladder. Patients further treated in the pain clinic stopped significantly less frequently than patients treated by GPs or other non-specialised physicians (5 versus 23%). Patients with long-term opioid intake revealed significantly lower pain intensity and higher contentment with the pain management and achieved improvement (global, quality of life and physical state). Changes of opioid dosages during the 5 years were inconsistent (no change 33%, decrease 16%, slight increase 27%, high increase 19%). However, the number of patients with high dose increased from 6 to 23 due to significant loss of efficacy (proved in the morphine subgroup, p<0.05). The survey demonstrates a very low frequency of withdrawal in patients with long-term opioid medication after initial response without evidence for tolerance development, especially if their treatment is controlled in a pain centre.

Zur Problematik von Akupunkturstudien am Beispiel der Methodik von gerac

OBJECTIVE

Conflicting or ambivalent findings on the effectiveness of body acupuncture in pain treatment are often attributed to flaws in study methodology. The paper describes the methodology used for the German Acupuncture Trials (gerac), which demonstrates that it is possible to design acupuncture studies in accordance with the standards of good clinical practice.

METHOD

Approximately 1000 chronic pain sufferers per indication (migraine, tension-type headache, low back pain (cLBP), or gonarthrosis) are randomly allocated to one of three treatment groups (verum acupuncture, sham acupuncture, or established conservative therapy). Patients are blind to the type of acupuncture. All patients receive ten sessions of treatment (two per week) with an option of adding five more treatments in cases of slight but insufficient improvement (number of headache days or von Korff pain score). Participating physicians are in private practice, representing a variety of specialties. All have completed at least a 140-hour training course in acupuncture. Mandatory and optional verum and sham points are predefined. The point selection is individualized according to the criteria of traditional Chinese medicine (TCM). Primary outcome measures are number of headache days per month, von Korff Graded Chronic Pain Scale or Hannover Functional Ability Questionnaire (cLBP), or WOMAC scores (gonarthrosis). Data are assessed by trained telephone interviewers not involved in treatment and blind to types of acupuncture.

PRESENT STATUS

Over 500 participating physicians in ten urban areas of Germany. Patient recruitment for cLBP and gonarthrosis was completed in November 2003 and March 2004 respectively. Recruitment for chronic headaches will be completed in autumn 2004.

CONCLUSIONS

The gerac trials prove that it is possible to design and carry out acupuncture studies in accordance to stringent standards of methodology and clinical practice. The results will form a basis for the assessment of acupuncture effectiveness in Germany and abroad.

Applied behavior management and acquired brain injury: approaches and assessment

Individuals who have acquired brain injury (ABI) may express themselves through the use of challenging behaviors, such as aggression, withdrawal, disinhibition, and self-destructive behaviors. This article describes the effectiveness of behavior interventions derived from the assessment of behavior in a community-based setting. The premise is that behavior, no matter how difficult, has function, purpose, and meaning for the individual. A therapeutic model of behavior assessment is presented that bases its strength on behavior assessment and well-trained staff. A well-formulated behavior management plan is developed, reinforcing alternative behaviors teaching skills, and reducing unwanted behaviors. Through the use of data collection methods, the treatment team identifies variables related to unwanted behavior and outcomes of consequences as they relate to the behavior. Illustrated through a case study, the behavioral treatment model is defined through behavior identification, initial assessments, treatment approaches, and tracking outcomes.

Behavior adjustments in traumatic brain injury. A case study

A traumatic assault to the brain often leaves significant residual effects, including severe behavioral dyscontrol. The person may demonstrate unwanted behaviors, such as physical aggression or verbal abuse, and lack motivation or the skills to engage in desirable behavior. ReMed, a community-based brain injury program, specializes in using a behavior analytic approach to address unwanted behaviors while understanding and developing strategies to further recovery from the brain injury.

New sialyltransferase inhibitors based on CMP-quinic acid: development of a new sialyltransferase assay

Quinic acid (4) was transformed into phosphitamides 6, 14, and 15, which could be readily linked to 5'-O-unprotected cytidine derivative 7; ensuing oxidation of the obtained phosphite triesters with tert-butylhydroperoxide furnished the corresponding phosphate triesters 8, 16, and 17, respectively. Hydrogenolytic debenzylation of the phosphate moiety, base catalysed removal of acetyl protective groups, and basic hydrolysis of the methylester of the quinic acid moiety furnished CMP-Neu5Ac analogues 1-3. In order to measure their inhibition of sialyltransferases, a nonradioactive sialyltransferase assay [employed for alpha(2-6)-sialyltransferase from rat liver (EC 2.4.99.1)] based on reversed-phase HPLC separation of UV-labelled acceptor 20 (p-nitrophenyl glycoside of N-acetyllactosamine) from the UV-labelled product 21 (p-nitrophenyl glycoside of sialyl alpha(2-6')-N-acetyllactosamine) and p-nitrophenylalanine as internal standard was developed. The assay reproduced the reported K(M) values for CMP-Neu5Ac and N-acetyllactosamine and the Ki values for CDP. 1 and 2 turned out to be potent sialyltransferase inhibitors.

Interaction of beta-adrenergic agonists and antagonists with the stimulation of growth hormone release induced by clonidine or by morphine in the rat

The beta-adrenergic agonist, isoprenaline, and antagonist, propranolol, had no effect on the delayed basal secretion of GH consistently observed in rats treated with the narco-analgesic gamma-hydroxybutyrate. Under the same experimental conditions, GH release was distinctly stimulated by infusion of the alpha-adrenergic agonist, clonidine, and by morphine; both responses were dose-dependent. The effects of beta-adrenergic agonists and antagonists on these GH responses were as follows: in rats pretreated with isoprenaline -the GH release induced by clonidine and morphine was abolished whereas it was enhanced in rats pretreated with propranolol. These data confirmed and extended previous reports from this laboratory on the inhibitory role of beta-adrenergic receptors on GH regulation.

Growth hormone responses to the stimulation of hypothalamic glucoreceptors in diabetic retinopathy. Effects of catecholamine precursors and dopamine antagonists

The effects of the stimulation of glucoreceptors located at the level of the lateral hypothalamic nuclei and sensitive to intracellular glucose deprivation on growth (GH) release are well documented in the monkey. In this study the effect of a reproducible hypoglycemic stimulatory procedure was controlled by continuously monitoring blood glucose (BG) levels in normal subjects and in a series of 120 diabetic patients. In contrast to control subjects, GH responses to similar hypoglycemic nadirs were not reproducible in diabetics (with or without diabetic retinopathy). The infusion of levodopa, precursor of both norepinephrine (NE) and dopamine, during BG decline rendered the GH response to hypoglycemia consistently reproducible. To investigate the site of action of levodopa, a group of diabetics were pretreated with a centrally active dopamine antagonist, metoclopramide hydrochloride. The pattern of GH release was similar in both groups. These data suggest that in diabetes the interaction of levodopa and adequate stimulation of hypothalamic glucoreceptor systems is mediated by an NE transmission.

Monoaminergic regulation of growth hormone in the rat

The administration of gamma-hydroxybutyrate (GHB) induced a consistent secretory episode of growth hormone (GH) in the morning followed by basal levels of secretion of GH for several hours. The measurement of endogenous noradrenaline, dopamine and serotonin (5-HT) following infusion of GHB showed that dopamine concentrations were significantly increased in the striatum; at the level of the hypothalamus, however, no significant differences were observed between control and GHB-treated animals. The data reported in this study are consistent with the interpretation that the neurotransmitter regulation of GH release and the modulation of hypothalamic glucoreceptor systems are not fundamentally different in rodents and primates. Clonidine, and alpha-adrenergic agonist, enhanced the peak of GH observed in the morning and caused a rapid increment of GH during the period when it was normally at basal levels. Under the same experimental conditions, dopamine agonists, apomorphine and levodopa, had no effect on GH secretion. The inhibition of catecholamine synthesis by alpha-methyl-p-tyrosine blocked the secretory episode of GH following administration of GHB and after insulin hypoglycaemia whereas the GH rise induced by clonidine was unchanged. The inhibition of 5-HT synthesis by p-chlorophenylalanine also suppressed the secretory episode of GH seen in the morning and the release of GH induced by hypoglycaemia; both being partly restored in animals pretreated with 5-hydroxytryptamine.

Circadian patterns of growth hormone, prolactin and corticotrophin secretion in hypothalamic and extra-hypothalamic lesions localized by stereotactic neuro-radiology in humans

The integrity of mediobasal hypothalamus for the maintenance of normal circadian rhythms has been clearly established in the animal. Using precise stereotactic neuroradiologic localisations of various brain tumors, the authors demonstrate that in human, cortical lesions induce no significant modifications of the circadian variation of GH, prolactin or ACTH. In contrast subcortical lesions displacing the 3rd ventricle result in an inhibiton of the nocturnal rise in GH and prolactin, whereas the circadian rhythm of ACTH remains normal.

Distribution of beta2-microglobulin in cerebrospinal fluid and in cystic fluid of brain tumors. A preliminary study

The concentrations of immuno-reactive beta2-microglobulin (beta2m) were measured in the cerebrospinal fluid (CSF) and the cystic fluid (CF) of Central Nervous System (CNS) tumours (gliomas, n = 5; craniopharyngiomas, n = 5) and in the culture medium of established cell lines derived from CNS tumors. These data are compared with plasma and CSF values of beta2m in normal subjects (n = 15) and in a group of peripheral solid tumors (metastatic breast carcinomas, n = 9). In the control group the absence of correlation between plasma and CSF values, suggests an independant production of beta2m in the two compartments considered. The capacity of CNS tumor cells to synthesize beta2m is demonstrated in vitro. In vitro beta-2m concentrations in the CF embryonic tumors (craniopharyngiomas) is significantly more elevated than in non malignant astrocytomas.

[The effect of anesthetics on the basal secretion of immunoreactive growth hormone in rats]

The authors investigated basal levels of plasma immunoreactive growth-hormone in the rat (R-GH) after administration of 3 different anesthetic drugs: urethan, chloral hydrate and gamma-hdroxy-butyrate (GHB). Lowest R-GH concentrations (5 +/- 3 ng/ml) are observed after urethan; they are significantly higher (15 +/- 4 ng/ml) after chloral hydrate but this anesthetic also causes hyperglycemia (210 +/- 30 mg/100 ml). Normal blood glucose levels are observed under GHB narco-analgesia which elicits a clear-cut R-GH secretory episode (70 +/- 5 ng/ml); basal values (12 +/- 3 ng/ml) are maintained for several hours thereafter.

Effects of inhibitors of catecholamine synthesis and catecholamine agonists on morphine- and hypoglycaemia-induced release of growth hormone in the rat

Unité de Neuroendocrinologie, INSERM, U.159, 2 ter Rue d'Alesia, 75014 Paris, France

(Received 16 August 1977)

It is known that catecholamines play an important role in the regulation of growth hormone (GH) secretion, but the effects of dopamine and alpha- and beta-adrenergic agonists on the release of GH in the rat are controversial (Collu, Fraschini, Visconti & Martini, 1972; Kato, Dupre & Beck, 1973; Durand, Martin & Brazeau, 1977). It has been proposed (Bluet-Pajot, Schaub & Nassiet, 1976; Bluet-Pajot & Schaub, 1977; Durand et al. 1977) that the conflicting data obtained in the rat may be due to the anaesthesia; most of the GH responses reported to be atypical in the rat, compared with those of primates, were obtained under urethane anaesthesia, which is known to result in long-lasting and irreversible endocrine imbalance.

In contrast, neurotransmitters or experimental hypoglycaemia do not appear to induce paradoxical GH responses in rats treated

Growth hormone response to hypoglycemia under gamma-hydroxybutyrate narco-analgesia in the rat

Plasma immuno-reactive growth-hormone (RIA-GH) concentrations were investigated under in vivo continuous blood glucose (BG) monitoring after administration of gamma-hydroxybutyrate (GHB) as well as during spontaneous or insulin-induced hypoglycemia. During the narco-analgesia by GHB a marked secretory episode is consistently observed. This secretion peak is not accurately time related with GHB administration and seems to fade off in aging animals. Strictly controlled hypoglycemia elicits a consistent and specific GH release. In contrast deep hypoglycemic levels resulting in a state of metabolic stress inhibit GH secretion. Our results suggest that previous data on the GH regulation pattern during hypoglycemia may depend upon the anesthetic used and/or nonspecific stress responses following deep hypoglycemia. The above mentioned experimental conditions indicate that GH metabolic regulation is not fundamentally different in rodents and primates.

Interaction of morphine and hypoglycaemia in stimulating the release of growth hormone in the rat

Unité de Neuroendocrinologie, INSERM – U.159, 2ter rue d'Alésia, 75014 Paris, France

(Received 16 February 1977)

It has been reported by Kokka, Garcia, George & Elliott (1972) and Martin, Audet & Saunders (1975) that morphine stimulates the release of growth hormone (GH) in the rat. Previous studies from this laboratory indicated that another narcoanalgesic, gamma-hydroxybutyrate (GHB), is able to stimulate immunoreactive GH secretion, but the pattern of this response differs markedly from that elicited by morphine (M. T. Bluet-Pajot & C. Schaub, unpublished results). We have also used GHB and eliminated stress effects to demonstrate that GH secretion in the rat can be induced by controlled hypoglycaemia as in primates (Bluet-Pajot, Schaub & Nassiet, 1976).

In the present study we have investigated whether morphine could elicit a GH response under GHB narcoanalgesia, and whether GH secretion induced by spontaneous or provoked hypoglycaemia interfered with this effect.

Automated blood glucose monitoring

Interstitial gamma irradiation by 198Au of the pituitary in diabetic retinopathy. Selective growth hormone blockade and ocular results

Pituitary interstitial irradiation by stereotaxic implantation of a gamma pointemitter was performed in 110 patients with progressing diabetic retinopathy. Reduction of growth hormone secretion peaks was delayed, but was consistent and selective in all cases controlled by somatotropin stimulation test, while other pituitary secretions remianed unchanged in all but five cases. In 31 patients who had no associated photocoagulation, long-term postoperative assessment showed significant improvement of hemorrhages and intrarentinal new vessels with preservation of visual acuity. Preretinal vascular proliferation (except when treatable by photocoagulation), extensive retinitis proliferans, and macular deterioration are contraindications. This technique represents a new approach in the functional pituitary neurosurgical treatment of diabetic retinopathy and differs from all other procedures that result in a more or less complete hypophysectomy.

[Indications and results of interstitial hypophyseal stereo-gammatherapy in the treatment of diabetic retinopathy]

New interest for pituitary neurosurgery in diabetic retinopathy is based on several data: long-term efficacy of various medical therapeutic agents is still unproved, ocular treatment by photocoagulation remains symptomatic, growth-hormone (HGH) has a permissive or supportive role in the development of diabetic retinopathy. Stereo-GIHF performs the pituitary interstitial irradiation by stereotaxic implantation of a gamma point emitter (198Au) and results in the selective blockade of HGH secretion peaks. Different from all other procedures achieving a more or less complete hypophysectomy, Stereo-GIHF introduces a new trend for the functional neurosurgical treatment of diabetic retinopathy.

Distribution of growth hormone and thyroid-stimulating hormone in cerebrospinal fluid and pathological compartments of the central nervous system

Human growth hormone (HGH) radio-immunoassay (RIA) was adapted for an accurate measurement of immunoreactive HGH concentrations in the CSF in different cases of hypothalamic-somatotropin dysfunctions. In control subjects (n = 43) mean HGH levels were 0.35 +/- 0.03 ng/ml in CSF and 1.95 +/- 0.2 ng/ml in plasma with a CSF/plasma ratio of 17%. The thyroid-stimulating hormone (TSH) RIA gave in controls mean basal levels of 2.65 +/- 0.2 muU/ml in CSF and 5.95 +/- 0.3 muU/ml in plasma with a CSF/plasma ratio of 44%. HGH and TSH concentrations in CSF and plasma show a very good correlation; but the regression curves for both hormones are distinctly different and appear specific for each polypeptide hormone. Hypothalamic-somatotropin hyperreactivity was reported in diabetic retinopathy (DR). CSF and plasma HGH concentrations in a group of diabetic patients with progressing retinopathy (n = 27) were not different from those in normal subjects (respectively 0.35 +/- 0.05 in CSF and 2.10 +/- 0.25 ng/ml in plasma with a CSF/plasma ratio of 16%). The HGH regression curve obtained in diabetics is similar to that of controls. These data do not substantiate the hypothesis of an HGH hyperreactivity in diabetic retinopathy. In somatotropin hypersecretion (acromegaly) without adenoma suprasellar extension, higher HGH concentrations recorded in CSF than in plasma cannot be attributed to an anatomical break-down of the CSF blood-brain barrier and suggest an active transport process of pituitary hormones to the CNS. HGH and TSH concentrations were measured in the cystic fluid of CNS tumors. In 1 case of a cystic dysembryoma, the HGH and TSH of CF were considerably increased. In gliomas (n = 8) the HGH and TSH cystic fluid concentrations were more elevated (respectively 0.72 +/- 0.2 ng/ml and 3.6 +/- 0.7 muU/ml) than in the CSF of controls.