Familial Adenomatous Polyposis Associated With Bilateral Adrenocortical Tumors and Agressive Desmoid Tumor

Background: Familial adenomatous polyposis (FAP) is an autosomal dominant condition caused by germline mutation in the tumor suppressor gene APC. FAP occurs in 1 to 10.000 individuals, and is characterized by hundreds to thousands of colonic adenomatous polyps with a high risk of developing into colorectal cancer. Extracolonic manifestations can be malignant or benign. The major causes of morbidity and mortality in patients with FAP are abdominal desmoid tumors, with incidences ranging between 7% and 17%. Adrenal incidentaloma are frequently discovered in these patients, generally as benign lesions when they undergo abdominal CT-scan in the course of surveillance. Adrenal lesions in FAP ranged from 7.4% to 16%. We described an unusual patient with FAP, associated with autonomous cortisol production due to bilateral adrenal tumors and the development of aggressive desmoid tumor after unilateral adrenalectomy. Clinical Case: A 33-years-old female FAP-patient presented with abdominal pain, weight gain (10kgs), humor instability, paroxysmal of chest pain, dizziness and tremors. The abdominal MRI showed a heterogeneous, left adrenal mass (9.0 x 7.9 x 6.7cm), suspected for malignant tumor, and right adrenal mass with 3.6 x 1.8 cm suggestive of adenoma. Abdominal CT and PETCTFDG revealed on the left adrenal lesion with 33UH and maxSUV 3.9 and a right adrenal lesion 13UH and maxSUV 3.1. Serum hormone levels were as follows: cortisol after DST (1mg-dexamethasone) 4.8 ug/Dl, ACTH 8,8pg/Ml with no other abnormal hormone secretion detected. Patient underwent left adrenalectomy. Histological analysis revealed Weiss 1, modified Weiss 2 and Ki67 <1% compatible with adenoma. On follow-up, abdominal MRI revealed a 4.3cm-solid-homogeneous mass at the surgical incision, suspected of malignance. The mass progressively enlarged to 6.3 cm in diameter. Histological analysis of the biopsy identified a desmoid tumor. The contralateral adrenal tumor maintained stable during the follow-up; however, it began to produce cortisol autonomous secretion as observed on DST. The patient developed metabolic syndrome and did not present classical Cushing’ syndrome. Contralateral adrenalectomy was contraindicated because of concern of emergence of a new desmoid tumor. Discussion: FAP-associated with adrenal tumors can produce mineralocorticoids, corticosteroids, or both. Although adrenal cortical tumors have been reported frequently in FAP patients, the presence of bilateral commitment tumors on adrenal glands is extremely rare. Conclusion: We reported a woman with FAP and bilateral adrenal tumors with non-synchronic cortisol secretion associated with an aggressive desmoid tumor developing after the adrenalectomy. The patient is taking an adrenal inhibitor of steroidogenesis to control cortisol secretion and to provide clinical improvement.

SAT-064 Validation of Furosemide Upright Test in Primary Aldosteronism Diagnosis Using Direct Renin Assay

Primary aldosteronism (PA) is the most common cause of endocrine hypertension. The 2016 Endocrine Society’s Guideline for PA management recommend that patients with a positive screening undergo one or more confirmatory tests to definitively confirm or exclude the diagnosis. Confirmatory testing procedures include oral sodium loading, saline infusion test (SIT), fludrocortisone suppression, captopril test (CT) and furosemide upright test (FUT). The FUT, mainly proposed by the Japan Endocrine Society, does not have limitation in patients with severe uncontrolled hypertension and heart failure. A positive FUT is defined as a plasma renin activity (PRA) <2 ng/mL/h after 2h, but it has not been standardized using a direct renin assay. The aim of this prospective study was to evaluate the FUT positive rate in a Brazilian cohort of PA patients and to establish a cut-off level to confirm PA diagnosis using direct renin concentration (DRC). We performed the FUT in 45 consecutive patients (25 males; median age 50 yrs, from 31 to 67 yrs) with PA diagnosis confirmed by biochemical cure after unilateral adrenalectomy or by adrenal venous sampling. Patients received furosemide 40 mg iv and stayed in upright position for 2h, starting at 8-9.30 AM. Blood samples for DRC, aldosterone, and potassium were drawn at time zero and after 2h. Aldosterone and DRC were measured by a chemiluminescent immunoassay (LIAISON®). Median A/DRC ratio was 10.3 (range, 2.54 to 66.4). Hypokalemia was evidenced in 27 out of 45 (60%) patients. Median DRC before and after 2h FUT was 2.8 uUI/mL (1.2 to 8.3) and 3.0 uUI/mL (0.5 to 19), respectively. Using the conversion factor of 12 to calculate PRA, FUT was positive (DRC/12= PRA <2 ng/mL/h) in all patients. Based on the highest renin level after FUT, the most suitable cut-off of direct renin concentration to confirm PA diagnosis was 20 uUL/mL. Additionally, potassium levels did not significantly change after FUT. Among these 45 PA patients, 39 performed an additional confirmatory test (recumbent SIT in 24 and CT in 15 patients). The positive rate for SIT was 83% using an aldosterone cut-off of 10 ng/dL and 100% using a cut-off of 6.8 ng/dL. CT and FUT were positive in all PA patients. In conclusion, FUT was a safe and reliable test for PA confirmation. In addition, we suggest a renin cut-off <20 uUI/mL after FTU to confirm PA diagnosis. Support: CNPq (403256/2016-0) to MQA

Complete resolution of hypercortisolism with sorafenib in a patient with advanced medullary thyroid carcinoma and ectopic ACTH (adrenocorticotropic hormone) syndrome

BACKGROUND

The treatment of advanced medullary thyroid carcinoma (MTC) has evolved significantly over the past decade. The discovery of genetic abnormalities in MTC has led to the development of targeted therapies such as vandetanib and cabozantinib. Other kinase inhibitors (KI), such as sorafenib, have been investigated in this setting and are an alternative therapeutic option. The lack of specificity of these KIs to a single target may result in additional, unexpected effects. In this report, we describe a patient with metastatic MTC and Ectopic ACTH (adrenocorticotropic hormone) Syndrome in whom treatment with sorafenib resulted in complete resolution of hypercortisolism.

SUMMARY

A 45-year-old male with progressive metastatic MTC presented with clinical manifestations suspicious for Cushing's syndrome. Investigation revealed ACTH-dependent hypercortisolism suggestive of Ectopic ACTH Syndrome. Treatment with sorafenib 400 mg twice a day was initiated resulting in a rapid and significant reduction of cortisol and ACTH levels associated with dramatic clinical improvement. The rapid and effective control of hypercortisolism in the absence of a significant tumor reduction raises the question of whether sorafenib may have a direct effect on ACTH or cortisol hypersecretion.

CONCLUSIONS

This report suggests a previously unknown potential effect of sorafenib on the pituitary-adrenal axis. Further studies will be necessary to investigate the role of sorafenib in other cases of ACTH excess and to understand the mechanisms by which it alters steroid synthesis, action, or secretion.

An inherited mutation outside the highly conserved DNA-binding domain of the p53 tumor suppressor protein in children and adults with sporadic adrenocortical tumors

Mutations of the p53 tumor suppressor gene are the single most common genetic alterations in human cancers. Recently, a distinct nucleotide substitution was identified in exon 10 of the p53 gene, leading to an Arg337His mutation in 97% of children with adrenocortical tumors from Southern Brazil. In the present study, we investigated the presence of this mutation in a larger series of 55 patients (37 adults and 18 children) with benign and malignant sporadic adrenocortical tumors. None of the patients had family cancer histories that conformed to the criteria for Li-Fraumeni syndrome. Twenty-one asymptomatic close relatives of patients with p53 mutations and 60 normal unrelated individuals were also studied. The missense Arg337His mutation was identified in 19 patients (14 children and 5 adults), and 8 of 11 cases studied had LOH. Among the 19 patients with the Arg337His mutation, only one boy and three adults showed fatal evolution or recurrent metastases. This mutation was also identified in heterozygous state in asymptomatic first-degree relatives of the patients, indicating that Arg337His mutation was inherited in most cases. In contrast, this mutation was not found in 120 alleles of normal unrelated controls. In conclusion, the germ line Arg337His mutation of p53 protein is present at a high frequency (77.7%) in children with benign or malignant sporadic adrenocortical tumors, but it is not restricted to the pediatric group, since 13.5% of adults with adrenocortical tumors also had this mutation. The presence of this mutation was related to unfavorable prognosis in most of the adults, but not in the children with adrenocortical tumors.

No evidence of somatic activating mutations on gonadotropin receptor genes in sex cord stromal tumors

OBJECTIVE

To search for somatic activating mutations of gonadotropin receptor (FSH-R and LH/chorionic gonadotropin receptor [CG-R]) genes as a cause of sex cord stromal tumors.

DESIGN

Molecular studies in human tissue.

SETTING

University hospital. SPECIMEN(S): Eight granulosa cell tumors collected from paraffin-embedded tissue, eight Leydig cell tumors, and three thecomas collected from fresh-frozen or paraffin-embedded tissue.

INTERVENTION(S)

Tumor samples were used for DNA extraction. The entire exon 11 of the LH/CG-R gene and a hot spot for gonadotropin receptor activating mutations on exon 10 of the FSH-R gene were amplified by polymerase chain reaction. The former was analyzed by denaturing gradient gel electrophoresis and automatic direct sequencing, and the latter by automatic direct sequencing.

MAIN OUTCOME MEASURE(S)

Results of denaturing gradient gel electrophoresis and automatic direct sequencing.

RESULT(S)

No somatic activating mutation was detected in exon 11 of the LH/CG-R gene in eight Leydig cell tumors and three thecomas. In addition, no mutations were detected in eight granulosa cell tumors in the hot spot for activating mutations in exon 10 of the FSH-R gene.

CONCLUSION(S)

Somatic activating mutations of gonadotropin receptors seem to play no relevant role in the development of sex cord stromal tumors.

Origin of an ovarian steroid cell tumor causing isosexual pseudoprecocious puberty demonstrated by the expression of adrenal steroidogenic enzymes and adrenocorticotropin receptor

Ovarian steroid cell tumors are rare neoplasms composed of typical steroid hormone-secreting cells. Most ovarian steroid cell tumors, however, cannot be appropriately classified on a morphological basis, because the neoplastic cells closely resemble adrenal cortical cells. Nevertheless, the true adrenal origin of such tumors has been difficult to demonstrate. Here we report a 3-yr-old girl with isosexual pseudoprecocious puberty due to an ovarian steroid tumor whose adrenal cell origin was determined by the presence of messenger ribonucleic acid (mRNA) of adrenal-specific steroidogenic P450 enzymes (P450c11 and P450c21) and ACTH receptor (ACTHR). Her height was +2.3 SD, and she had Tanner stage III breast development, Tanner stage II pubic hair, and a normal clitoris. Bone age was 5 yr. Basal gonadotropin levels were undetectable (<0.6 U/L for LH and <1.0 U/L for FSH) and remained undetectable after stimulation with 100 microg GnRH, i.v. Basal serum testosterone and 17-hydroxyprogesterone levels were slightly elevated, whereas basal serum androstenedione, estradiol, and dehydroepiandrosterone sulfate levels were clearly elevated. Pelvic ultrasound disclosed an enlarged uterus and an adnexal multicystic mass in the right ovary, and pathological studies disclosed an ovarian steroid cell tumor. To establish the cellular origin of the tumor we determined the presence of mRNA for P450c11, P450c21, and ACTHR in tumor tissue and normal adrenal and ovarian tissue. Detection of ACTHR, P450c21, and P450c11 mRNAs isoforms was achieved in tumoral and adrenal control tissue, but not in the ovary control tissue. The RT-PCR products of P450c11 from adrenal control tissue were composed by both BglI-sensitive and -resistant complementary DNAs, indicating the presence of both P450c11AS and P450c11beta, whereas RT-PCR product from the tumor was resistant to BglI digestion, indicating only the presence of P450c11beta. We conclude that the histological origin of so-called adrenal rest tumor could be reliably determined by assessing the expression of specific genes in the tumor as P450c11beta and P450c21. The use ofthese molecular tools will allow a more precise classification of an important subset of the ovarian steroid cell tumors and can help to identify ectopic adrenal tissue in ovary and testis.

Mutation analysis of the follicle-stimulating hormone receptor gene in girls with gonadotropin-independent precocious puberty resulting from autonomous cystic ovaries

OBJECTIVE

To search for germline activating mutations of the FSH receptor in girls with gonadotropin-independent precocious puberty.

DESIGN

Molecular studies in human tissue.

SETTING

Four girls with polycystic ovaries and gonadotropin-independent isosexual precocious puberty without clinical and molecular features of McCune-Albright syndrome.

INTERVENTION(S)

Peripheral blood was used for DNA extraction. The alpha-subunit of the Gs gene and the entire exon 10 of FSH receptor gene were amplified by polymerase chain reaction (PCR). Gs-alpha mutations characteristic of McCune-Albright syndrome were excluded by denaturating gradient gel electrophoresis (DGGE) and allele-specific PCR. Exon 10 of the FSH receptor gene was analyzed by DGGE and direct sequencing.

MAIN OUTCOME MEASURE(S)

Results of DGGE and direct sequencing.

RESULT(S)

No germline activating mutations were detected in exon 10 of our patients. Instead, two previously described polymorphisms were found, leading to the substitution of alanine for threonine at position 307 and of serine for asparagine at position 680 of the FSH receptor molecule.

CONCLUSION(S)

Germline activating mutations were not found in exon 10 of the FSHR gene in any of our patients. Further studies, preferably in ovarian tissue, will be required to exclude the presence of somatic activating mutations of the FSH receptor in these patients.

Tooth pulp- and facial hair mechanoreceptor-evoked responses of trigeminal sensory neurons are attenuated during ketamine anesthesia

BACKGROUND

Evidence exists that ketamine, administered systemically using a dose required for inducing a state of anesthesia, may antagonize nociceptive but not innocuous input to lumbar dorsal horn neurons. However, it is unclear whether ketamine exerts this selective action on sensory inputs to trigeminal sensory neurons. The current study was undertaken to compare the responses evoked in trigeminal sensory neurons by electrical stimuli applied to the tooth pulp versus air-puff stimuli applied to facial hair mechanoreceptors (FHMs) during quiet wakefulness versus ketamine anesthesia.

METHODS

Accordingly, responses of rostral trigeminal sensory nuclear complex (TSNC) and trigeminothalamic tract neurons evoked by tooth pulp (a source of small-diameter fiber input) and FHMs (a source of larger-diameter fiber input) were recorded extracellularly from chronically instrumented cats before, during, and after recovery from the anesthetic state induced by a single (2.2 mg/kg) intravenous injection of ketamine.

RESULTS

Overall, tooth pulp-evoked responses of TSNC neurons were maximally suppressed by 50% within 5 min after the intravenous administration of ketamine. Ketamine also suppressed the FHM-evoked responses of TSNC and trigeminothalamic neurons by 45%. The time course of ketamine's suppressive action was equivalent for tooth pulp- and FHM-evoked responses. However, the recovery of tooth pulp-evoked TSNC neuronal responses at suprathreshold intensities was markedly prolonged compared with neuronal responses driven by threshold stimuli or FHM.

CONCLUSIONS

These electrophysiologic results in the chronically instrumented cat preparation indicate that a nonselective suppression of orofacial somatosensory information occurs during ketamine anesthesia. The prolonged recovery of suprathreshold responses of TSNC neurons mediated by small-diameter afferent fiber input may partly underlie the analgesic action of ketamine that is clinically relevant at subanesthetic doses.

Treatment of gonadotropin dependent precocious puberty due to hypothalamic hamartoma with gonadotropin releasing hormone agonist depot

The gonadotropin releasing hormone (GnRH) secreting hypothalamic hamartoma (HH) is a congenital malformation consisting of a heterotopic mass of nervous tissue that contains GnRH neurosecretory neurons attached to the tuber cinereum or the floor of the third ventricle. HH is a well recognised cause of gonadotropin dependent precocious puberty (GDPP). Long term data are presented on eight children (five boys and three girls) with GDPP due to HH. Physical signs of puberty were observed before 2 years of age in all patients. At presentation with sexual precocity, the mean height standard deviation (SD) for chronological age was +1.60 (1.27) and the mean height SD for bone age was -0.92 (1.77). Neurological symptoms were absent at presentation and follow up. The hamartoma diameter ranged from 5 to 18 mm and did not change in six patients who had magnetic resonance imaging follow up. All patients were treated clinically with GnRH agonists (GnRH-a). The duration of treatment varied from 2.66 to 8.41 years. Seven of the eight children had satisfactory responses to treatment, shown by regression of pubertal signs, suppression of hormonal levels, and improvement of height SD for bone age and predicted height. One patient had a severe local reaction to GnRH-a with failure of hormonal suppression and progression of pubertal signs. It seems that HH is benign and that GnRH-a treatment provides satisfactory and safe control for most children with GDPP due to HH.

Activating mutation of the stimulatory G protein (gsp) as a putative cause of ovarian and testicular human stromal Leydig cell tumors

Activating mutations of the G protein genes have been associated with the development of several endocrine neoplasms. Such activating mutations, gip2, affecting the alpha-subunit of the G alpha i2 protein were previously described by a single group in 30% of ovarian sex cord stromal tumors. Other activating mutations of the alpha-subunit of the Gs (gsp) have been identified in GH-secreting and nonfunctioning pituitary tumors, autonomous thyroid adenomas, and all affected McCune-Albright tissues, but not in sex cord stromal tumors. In the present study, we investigated the presence of gip2 and gsp mutations in 14 human sex cord stromal tumors. Six Leydig cell tumors (4 ovaries and 2 testes), 2 thecomas, 2 granulosa cell tumors, 3 androblastomas, and 1 gonadoblastoma (sex cord and germ cell) were included in this study. Genomic DNA was obtained from either fresh-frozen tumor tissues or paraffin-embedded sections and in some cases from blood samples. Using PCR, denaturing gradient gel electrophoresis, and direct sequencing, we detected 4 tumors (66.6%) with the gsp mutation (R201C) in our series of ovarian and testicular Leydig cell tumors. In contrast, no gip2 mutations were found in any of the sex cord stromal tumors studied. In conclusion, our findings suggest that the putative oncogene gsp may play a significant role in the molecular mechanism of these tumors.

Spontaneous discharge and peripherally evoked orofacial responses of trigemino-thalamic tract neurons during wakefulness and sleep

In the present study, ongoing and evoked activity of antidromically identified trigemino-thalamic tract (TGT) neurons was examined over the sleep-wake cycle in cats. There was no difference in the mean spike discharge rate of TGT neurons when quiet sleep (QS) and active sleep (AS) were compared with wakefulness (W). However, tooth pulp-evoked responses of TGT neurons were decreased during AS when compared to W. Conversely, the responses of TGT neurons to air puff activation of facial hair mechanoreceptors reciprocally increased during AS when compared to W. The present data demonstrate that ascending sensory information emanating from distinct orofacial areas is differentially modified during the behavioral state of AS. Specifically, the results obtained suggest that during AS, sensory information arising from hair mechanoreceptors is enhanced, whereas information arising from tooth pulp afferents is suppressed. These data may provide functional evidence for an AS-related gate control mechanism of sensory outflow to higher brain centers.

Cortisol and adrenocorticotropin response to desmopressin in women with Cushing's disease compared with depressive illness

The pituitary-adrenal responsiveness to desmopressin of women with depressive illness was compared with that of patients with Cushing's disease, who are known to be highly responsive, and to that of normal controls, who are known to be poorly responsive to the peptide. Although 100% of the patients in the group with Cushing's disease met the response criterion with cortisol increases of 632 +/- 80 nmol/L above baseline (mean +/- SE), the prevalence of responders was 36% in the depressive group and 10% in normal controls, with cortisol changes from baseline of 154 +/- 28 and 79 +/- 15 nmol/L, respectively. All response parameters were significantly higher in the patients with Cushing's disease and did not differ between depressive patients and normal controls, who exhibited the same general pattern of cortisol and ACTH responses. It is concluded that the desmopressin test can be used in the differentiation between depression and Cushing's disease, and that the hypothalamic-pituitary-adrenal regulation is distinct in these two conditions.

Active-sleep-related suppression of feline trigeminal sensory neurons: evidence implicating presynaptic inhibition via a process of primary afferent depolarization

1. Changes in the excitability of lumbar and trigeminal primary afferent terminals have long been used as an index of primary afferent depolarization (PAD). PAD has been linked in part to the presynaptic inhibition of neurotransmission. During the behavioral state of active sleep, synaptic transmission through the rostral trigeminal sensory nuclear complex (TSNC) is suppressed when compared with other states such as wakefulness or quiet sleep. The mechanism underlying the suppression of neuronal activity in the rostral TSNC during active sleep is not known. Accordingly, experiments were conducted to determine, by examining the excitability of tooth pulp afferent terminals in cat during sleep and wakefulness, whether PAD processes might contribute in part to the suppression of rostral TSNC neuron activity. 2. Unitary potentials recorded in the maxillary canine tooth pulp were evoked by low-intensity stimuli applied to the rostral TSNC. Unitary potentials were identified by their "all-or-nothing" response, their invariant amplitude and latency, and their ability to follow a short train of high-frequency (333 Hz) stimuli. 3. The firing index (FI), a measure of the probability of evoking a unitary potential, was used to assess the changes in excitability of tooth pulp primary afferents. The proximity of stimulating electrodes to the terminal segment rather than a nonterminal segment of a tooth pulp afferent was demonstrated by observing an increase in the FI as a consequence of conditioning stimuli applied to ipsilateral branches of the trigeminal nerves. Increases in the FI over baseline were obtained for conditioning test intervals ranging from 20 to 80 ms, with the peak effect of conditioning occurring at 30 ms. 4. A total of 25 tooth pulp afferent terminals were identified and changes in their FI were examined during wakefulness, quiet sleep, and active sleep. The FI for all 25 terminals during wakefulness (FIW: 0.29 +/- 0.04, mean +/- SE) did not differ from that during quiet sleep (0.32 +/- 0.04). However, when compared with wakefulness, the FI during active sleep (FIAS: 0.52 +/- 0.07) was increased. The mean ratio of change in the FI (FIAS/FIW) was 3.5 +/- 0.9. These findings indicate that, as a population, tooth pulp afferent terminals are depolarized during the state of active sleep and that PAD processes may partly underlie the suppression of synaptic transmission through the rostral TSNC during this state. 5. To explore whether presynaptic excitability changes underlie the modulation of rostral TSNC neuron activity during active sleep, additional experiments were performed in which tooth-pulp-evoked responses of individual rostral TSNC neurons and the FIs of adjacent individual tooth pulp afferent terminals were analyzed as a function of sleep and wakefulness. The results indicated that active-sleep-related PAD was associated with active-sleep-related suppression of tooth-pulp-evoked activity of rostral TSNC neurons. 6. The conclusion is reached that PAD processes contribute to the mechanism whereby synaptic activity through the rostral TSNC is suppressed during the behavioral state of active sleep.

Dorsal spinocerebellar tract neurons in the chronic intact cat during wakefulness and sleep: analysis of spontaneous spike activity

Relatively little is known about the transmission of ascending sensory information from lumbar levels across the behavioral states of sleep and wakefulness. The present study used extracellular recording methods in chronically instrumented intact behaving cats to monitor the activity of lumbar dorsal spinocerebellar tract (DSCT) neurons within Clarke's column during the states of wakefulness, quiet sleep, and active sleep. Clarke's column DSCT neurons were identified using antidromic identification and retrograde labeling techniques. The spontaneous spike rate and interspike interval data of DSCT neurons were quantified as a function of behavioral state. During wakefulness and quiet sleep, the spike rate of DSCT neurons was stable, and interspike interval histograms (ISIH) indicated a relatively high degree of regularity in DSCT neuronal spike train patterns. In contrast, during active sleep there was a marked reduction in the ongoing spike rate in a vast majority of cells tested. The magnitude of change in ISIHs and interspike interval data during active sleep depended in part on whether the reduction in cell firing was maintained or periodic throughout active sleep. Further suppression of spontaneous activity also was observed during intense rapid-eye-movement episodes of active sleep that were associated with clustered pontogeniculo-occipital wave and muscular twitches and jerks. After re-awakening, spontaneous spike activity of Clarke's column DSCT neurons resembled that recorded during previous episodes of wakefulness. These data provide evidence that ascending proprioceptive and exteroceptive sensory transmission through Clarke's column is diminished during the behavioral state of active sleep.

Dorsal spinocerebellar tract neuronal activity in the intact chronic cat

The ability to electrophysiologically identify the axonal projections of lumbar neurons recorded in chronic unanesthetized intact awake animals is a formidable but essential requirement toward understanding ascending sensory transmission under naturally occurring conditions. Chronic immobilization procedures previously introduced by Morales et al. (1981) for intracellular studies of motoneurons are modified and then integrated with procedures for antidromic cellular identification and extracellular recording of upper (or lower) dorsal lumbar spinocerebellar tract (DSCT) neuronal activity, in conjunction with behavioral state recording and drug microiontophoresis. These implant procedures provide up to 6 months of stable recording conditions and, when combined with other techniques, allow individual DSCT neurons to be monitored over multiple cycles of sleep and wakefulness, following the induction into and recovery from barbiturate anesthesia and/or during the juxtacellular microiontophoretic ejection of inhibitory or excitatory amino acid neurotransmitters. The combination of such techniques allows a comprehensive examination of synaptic transmission through the DSCT and other lumbar sensory pathways in the intact normally respiring cat and its modulation during the general anesthetic state. These techniques permit investigations of the supraspinal controls impinging on lumbar sensory tract neurons during wakefulness and other behavioral states such as active sleep.

Activity of rostral trigeminal sensory neurons in the cat during wakefulness and sleep

1. Relatively little is known about the activity of trigeminal sensory neurons during naturally occurring behavioral states of sleep and wakefulness. Accordingly, experiments were performed in chronic unanesthetized behaving cats in which neuronal activity in the rostral trigeminal sensory nuclear complex (TSNC) was recorded extracellularly in response to low-intensity stimulation of mandibular and maxillary divisions of cranial V nerve. The peripheral responses of TSNC neurons were evaluated during naturally occurring episodes of wakefulness, quiet sleep, and active sleep. 2. The location of the rostral TSNC was confirmed by recording characteristic orthodromic field potentials generated in response to afferent volleys from tooth pulp and inferior alveolar (IAN) nerve stimuli. Antidromic fields from the trigeminal (MotV) and facial (MotVII) motor pools were used to demarcate the anterior and posterior limits of the rostral TSNC (i.e., main sensory nucleus and nucleus oralis pars gamma). 3. In the absence of peripherally applied stimuli, individual rostral TSNC neurons recorded in the chronic, unanesthetized cat during the behavioral state of wakefulness did not display ongoing spike activity. 4. The response characteristics of individual TSNC neurons to low-intensity stimuli delivered to V afferents emanating from the canine tooth pulps during the behavioral state of drowsy wakefulness consisted of a short train of action potentials characterized by a short latency-to-onset (7.2 +/- 0.4 ms, mean +/- SE, n = 51). TSNC neurons fell into two categories on the basis of their response to graded intensities of tooth pulp stimuli. "Stimulus intensity-dependent" neurons demonstrated evoked responses that had a response profile that increased with stimulus intensity. In contrast, the response profile of "stimulus intensity-independent" neurons remained stable irrespective of the stimulus intensity used. 5. During episodes of wakefulness and quiet sleep, IAN-evoked orthodromic fields did not differ in their amplitude or other waveform parameters. However, during active sleep, the IAN-evoked orthodromic field potential was suppressed by an average of 28% as compared with wakefulness. 6. The number of action potentials evoked by consecutive presentation of low-intensity tooth pulp stimuli were compared during sleep and wakefulness. The evoked responses were suppressed during active sleep (29%, n = 42). Suppression observed during active sleep occurred in both ("stimulus-dependent" and "stimulus-independent") groups of TSNC neurons. During the phasic rapid-eye-movement (REM) episodes of active sleep, both the orthodromic field potentials and unitary action potentials were further suppressed or abolished. 7. The conclusion is reached that synaptic transmission through the rostral trigeminal sensory nucleus is dependent on the behavioral state of the animal.(ABSTRACT TRUNCATED AT 400 WORDS)

The desmopressin stimulation test in the differential diagnosis of Cushing's syndrome

OBJECTIVE

We assessed the ability of desmopressin to stimulate the pituitary-adrenal axis in patients with Cushing's syndrome.

DESIGN AND SUBJECTS

The cortisol response to 5 ot 10 micrograms of intravenous desmopressin was evaluated in 31 patients with Cushing's syndrome of several aetiologies and in 15 normal subjects.

RESULTS

Cortisol responses were observed in 15 out of 16 patients with pituitary dependence and in two patients with adrenal nodular hyperplasia, the increase above baseline ranging from 61 to 379% in the responders. Eight patients with adrenal tumours and one with the ectopic ACTH syndrome did not respond to desmopressin, having shown changes in their cortisol levels from -5 to 42% above baseline. Responses occurred in two out of the 15 normal individuals, whose cortisol increased 58 and 69% above baseline, respectively. Stimulation tests with standard agents as lysine vasopressin or ovine corticotrophin-releasing hormone were performed in the same patients and there was a high degree of concordance. No serious adverse reactions were observed in the tests with desmopressin.

CONCLUSIONS

Desmopressin was able to stimulate the pituitary-adrenal axis in patients with Cushing's disease and, like corticotrophin releasing hormone, it may prove useful in the differential diagnosis of Cushing's syndrome.