Consensus and Diversity in the Management of Varicocele for Male Infertility: Results of a Global Practice Survey and Comparison with Guidelines and Recommendations

PURPOSE

Varicocele is a common problem among infertile men. Varicocele repair (VR) is frequently performed to improve semen parameters and the chances of pregnancy. However, there is a lack of consensus about the diagnosis, indications for VR and its outcomes. The aim of this study was to explore global practice patterns on the management of varicocele in the context of male infertility.

MATERIALS AND METHODS

Sixty practicing urologists/andrologists from 23 countries contributed 382 multiple-choice-questions pertaining to varicocele management. These were condensed into an online questionnaire that was forwarded to clinicians involved in male infertility management through direct invitation. The results were analyzed for disagreement and agreement in practice patterns and, compared with the latest guidelines of international professional societies (American Urological Association [AUA], American Society for Reproductive Medicine [ASRM], and European Association of Urology [EAU]), and with evidence emerging from recent systematic reviews and meta-analyses. Additionally, an expert opinion on each topic was provided based on the consensus of 16 experts in the field.

RESULTS

The questionnaire was answered by 574 clinicians from 59 countries. The majority of respondents were urologists/uro-andrologists. A wide diversity of opinion was seen in every aspect of varicocele diagnosis, indications for repair, choice of technique, management of sub-clinical varicocele and the role of VR in azoospermia. A significant proportion of the responses were at odds with the recommendations of AUA, ASRM, and EAU. A large number of clinical situations were identified where no guidelines are available.

CONCLUSIONS

This study is the largest global survey performed to date on the clinical management of varicocele for male infertility. It demonstrates: 1) a wide disagreement in the approach to varicocele management, 2) large gaps in the clinical practice guidelines from professional societies, and 3) the need for further studies on several aspects of varicocele management in infertile men.

Correction: Mitochondrial oxodicarboxylate carrier deficiency is associated with mitochondrial DNA depletion and spinal muscular atrophy-like disease

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The impact of hemolysis on Ortho-Clinical Diagnostic's ECi and Roche's elecsys immunoassay systems

BACKGROUND

Hemolysis is regularly encountered in clinical specimens and often interferes with a variety of laboratory test methods. Although not widely recognized, immunoassays based on nonisotopic detection systems can also be affected by hemolysis. For this reason, we investigated the effect of differing amounts of hemolysis across a range of values for several immunoassays on the Ortho-Clinical Diagnostics ECi and Roche Elecsys platforms.

METHODS

Hemolysate was prepared from whole blood and spiked at varying concentrations into pooled patient serum samples for different analytes.

RESULTS

Out of the 21 analytes tested, six (28.6%) exhibited significant increases or decreases in measured concentrations with increasing amounts of hemolysis.

CONCLUSIONS

Although immunoassays are generally thought to be impervious to hemolysis interference, hemolysis can interfere in immunoassay testing platforms. For these reasons, we recommend that laboratories conduct hemolysis interference studies for all laboratory test protocols.

Identification of genotypic changes in human immunodeficiency virus protease that correlate with reduced susceptibility to the protease inhibitor lopinavir among viral isolates from protease inhibitor-experienced patients

The association of genotypic changes in human immunodeficiency virus (HIV) protease with reduced in vitro susceptibility to the new protease inhibitor lopinavir (previously ABT-378) was explored using a panel of viral isolates from subjects failing therapy with other protease inhibitors. Two statistical tests showed that specific mutations at 11 amino acid positions in protease (L10F/I/R/V, K20M/R, L24I, M46I/L, F53L, I54L/T/V, L63P, A71I/L/T/V, V82A/F/T, I84V, and L90M) were associated with reduced susceptibility. Mutations at positions 82, 54, 10, 63, 71, and 84 were most closely associated with relatively modest (4- and 10-fold) changes in phenotype, while the K20M/R and F53L mutations, in conjunction with multiple other mutations, were associated with >20- and >40-fold-reduced susceptibility, respectively. The median 50% inhibitory concentrations (IC(50)) of lopinavir against isolates with 0 to 3, 4 or 5, 6 or 7, and 8 to 10 of the above 11 mutations were 0.8-, 2.7-, 13.5-, and 44.0-fold higher, respectively, than the IC(50) against wild-type HIV. On average, the IC(50) of lopinavir increased by 1.74-fold per mutation in isolates containing three or more mutations. Each of the 16 viruses that displayed a >20-fold change in susceptibility contained mutations at residues 10, 54, 63, and 82 and/or 84, along with a median of three mutations at residues 20, 24, 46, 53, 71, and 90. The number of protease mutations from the 11 identified in these analyses (the lopinavir mutation score) may be useful for the interpretation of HIV genotypic resistance testing with respect to lopinavir-ritonavir (Kaletra) regimens and may provide insight into the genetic barrier to resistance to lopinavir-ritonavir in both antiretroviral therapy-naive and protease inhibitor-experienced patients.

Accuracy of CPT evaluation and management coding by family physicians

BACKGROUND

Limited data are available on physicians' accuracy in coding for their services. The purpose of this study was to determine the current procedural terminology (CPT) evaluation and management coding accuracy of family physicians and define demographic variables associated with coding accuracy.

METHODS

Six hundred randomly selected active members of the Illinois Academy of Family Physicians were sent six hypothetical progress notes of office visits along with a demographic survey. The study group assigned CPT evaluation and management codes to each of the progress notes and completed the demographic survey. Five expert coders also assigned codes to each of the cases. The accuracy of family physicians in determining CPT E/M codes was determined relative to that of expert coders.

RESULTS

Family physicians agreed with the experts' CPT evaluation and management codes for 52% of established patient progress notes, the most common error being undercoding. In contrast, for new patient progress notes, family physicians agreed with the experts only 17% of the time, the predominant error being overcoding. No surveyed demographic variable was associated with coding accuracy.

CONCLUSIONS

The error rate for physician CPT coding is substantial and occurs more commonly with new patients. The complexity of the CPT coding guidelines, along with limited physician training in CPT coding, likely account for these results.

Preoperative evaluation

A history and physical examination, focusing on risk factors for cardiac, pulmonary and infectious complications, and a determination of a patient's functional capacity, are essential to any preoperative evaluation. In addition, the type of surgery influences the overall perioperative risk and the need for further cardiac evaluation. Routine laboratory studies are rarely helpful except to monitor known disease states. Patients with good functional capacity do not require preoperative cardiac stress testing in most surgical cases. Unstable angina, myocardial infarction within six weeks and aortic or peripheral vascular surgery place a patient into a high-risk category for perioperative cardiac complications. Patients with respiratory disease may benefit from perioperative use of bronchodilators or steroids. Patients at increased risk of pulmonary complications should receive instruction in deep-breathing exercises or incentive spirometry. Assessment of nutritional status should be performed. An albumin level of less than 3.2 mg per dL (32 g per L) suggests an increased risk of complications. Patients deemed at risk because of compromised nutritional status may benefit from pre- and postoperative nutritional supplementation.

Biophysical properties and responses to glutamate receptor agonists of identified subpopulations of rat geniculate ganglion neurons

The goal of the current study was to evaluate the electrophysiological properties and responses to glutamate receptor agonists of rat geniculate ganglion (GG) neurons innervating the tongue. Subpopulations of GG neurons were labeled by injecting Fluoro-Gold (FG) or True Blue chloride into the anterior tongue and soft palate (AT and SP neurons) and applying FG crystals to the posterior auricular branch of the facial nerve (PA neurons). Three to 12 days later, the GG neurons were acutely isolated and patch clamped. Although many biophysical properties of the AT, SP and PA neurons were similar, significant differences were found among these groups in properties related to cell excitability. For example, the average amount of current necessary to elicit an action potential was 61 pA in AT neurons (n=55), 90 pA in SP neurons (n=41) and 189 pA in PA neurons (n=35, P<0.001). In addition, AT neurons tended to fire significantly more action potentials during depolarization as well as following hyperpolarizing pulses than SP or PA neuron types. Most GG neurons responded to application of glutamate receptor agonists. The neurons responded with a depolarization accompanied by a reduction in input resistance. These results suggest that subpopulations of neurons in the geniculate ganglion have distinct biophysical properties and express functional glutamate receptors. The differing biophysical properties of GG neurons is possibly related to their functional heterogeneity and glutaminergic neurotransmission may function in the processing of gustatory, and other sensory information, within the geniculate ganglion and its projections.

Evaluation of nursing home patients. A systematic approach can improve care

As the US population ages, the proportion of patients receiving long-term care is increasing. To meet the challenge of providing quality care for these patients, physicians need to be prepared to efficiently evaluate their needs and formulate individualized care plans. In this article, Drs King and Lipsky discuss the unique aspects of caring for nursing home patients, including the role of patients' families in the overall plan. They present a practical, structured approach to evaluation and follow-up care, which they have encapsulated into two handy assessment forms.

Adrenal insufficiency: an uncommon cause of fatigue

BACKGROUND

Adrenal insufficiency is a rare condition that can cause common and nonspecific symptoms. One such symptom, reported by all patients with adrenal insufficiency, is fatigue. On the other hand, up to 20% of patients seeking care from primary care physicians will have fatigue as a complaint. Only a small percentage of patients are found to have underlying medical disease.

METHODS

A MEDLINE literature search was performed from 1966 to the present using the key words "fatigue," "adrenal insufficiency," and "polyglandular autoimmune endocrinopathy." Major endocrinology textbooks were also referenced. In addition, references were obtained from bibliographies of available articles.

RESULTS AND CONCLUSIONS

This article describes a patient with adrenal insufficiency and fatigue as the primary complaint. A brief discussion of fatigue and clues to organic causes follows, along with a more detailed discussion of adrenal insufficiency. Important medical history or signs and symptoms of organic disease suggest the need for screening tests and more detailed evaluation to uncover the uncommon medical causes of fatigue.

A subpopulation of neurons in the rat rostral nucleus of the solitary tract that project to the parabrachial nucleus express glutamate-like immunoreactivity

In rodents, gustatory information is transmitted from second order neurons in the rostral nucleus of the solitary tract (rNST) to the parabrachial nucleus (PBN) in the pons. The chemical nature of this projection is unknown. Therefore, the goal of the current study was to determine if rNST neurons that project to the PBN express glutamate-like immunoreactivity. Projection neurons were retrogradely labeled following stereotaxic injection of rhodamine-filled latex microspheres into the right PBN of seven rats while glutamate-immunoreactive (GLU-IR) structures were visualized in the same tissue using an immunoperoxidase procedure. The number of single- and double-labeled neurons located in the right (ipsilateral) and left rNST, in each of the nuclear subdivisions as well as their position along the rostral-caudal axis of the rNST was determined. GLU-IR cell bodies were located throughout the rNST. Although the rostral central subdivision contained the highest percentage (33.8%) of GLU-IR perikarya, immunolabeled neurons were most concentrated (number/area of subdivision) within the medial subnucleus. The rostral third of the rNST contained the fewest (20. 5%) and lowest density of GLU-IR cell bodies. The highest percentage of rNST neurons retrogradely labeled from the PBN were located ipsilateral (85.4%) to the pontine injection site, in the middle third of the nucleus (44.2%) and within the rostral central subdivision (52.4%). Overall, 18% of the labeled rNST projection neurons were GLU-IR. The distribution of double-labeled neurons mirrored that of the projection neurons with the largest number located in the ipsilateral rNST (84.5%), middle third of the nucleus (40.5%) and rostral central subdivision (64.7%). These results indicate that glutamate may be a main component of the ascending pathway from the rNST to the PBN. In addition, since GLU-IR neurons were located throughout the rNST and most were not retrogradely-labeled, the current results suggest that glutamate may be an important neurotrans-mitter within the medulla.

The influence of the full blood count on medical inpatient management

AIM

This investigation studied the use of the full blood count (FBC) in a general medical inpatient ward at Groote Schuur Hospital.

OBJECTIVES

To determine the relative frequency of the reasons for which FBCs were requested (clinically indicated v. routine) and how they influenced patient management.

PATIENTS

One hundred and sixty-five consecutive general medical inpatients admitted to the ward between September and December 1993 were included. Each patient underwent an FBC and differential white cell count prior to entering the ward.

DESIGN

After taking a history and examining the patient, the physician responsible for each of the 165 patients completed a questionnaire.

OUTCOMES MEASURED

Physicians had to indicate whether the FBC was routine or clinically indicated and how the FBC result influenced their patient management.

RESULTS

In 67.9% of cases the FBC was considered to be clinically indicated, while in 32.1% of cases it was routine. Although it was felt that 76.4% of the clinically indicated tests influenced patient care, patient management was changed in only 24.7% of cases. In the case of routine tests, care was influenced in only 2.0% of cases.

CONCLUSION

Routine tests have a very low clinical yield. There is no substitute for good clinical judgement and the practice of routine tests must be reviewed, as much time, money and patient discomfort could be saved by the elimination of unnecessary investigations.

District level information systems: two cases from South Africa

The health system in South Africa has to date been fragmented and centralised. The priority of the new government is to establish an integrated and decentralised district health system of which a key element is the development of district health and management information systems (H & MIS). This paper presents experiences from two projects in the Western Cape in which a process to establish a district-based H & MIS was initiated and a situation analysis of the information systems was done. The two projects applied different research methods but the results show with remarkable consistency that much time is used on data collection, but information is not used at local level. The projects have applied different approaches towards developing a district H & MIS but in both important pre-requisites for a successful, action-led H & MIS include local ownership and motivation, a process based around existing local management structures and the active involvement of the community.

Demonstration of a bilateral projection from the rostral nucleus of the solitary tract to the medial parabrachial nucleus in rat

This study examined the projection from the rostral nucleus of the solitary tract (rNST) to the medial parabrachial nucleus (mPBN) in male Wistar rats using DiI as a retrograde tracer and biotinylated dextran as an anterograde tracer. Following successful unilateral injection of DiI into the mPBN (n = 8), retrogradely labeled neurons were always found in the rNST both ipsilateral and contralateral to the pontine injection site. Significantly, approximately 25% of the total number of DiI-labeled neurons were located in the contralateral rNST. The labeled neurons were located throughout the rostral-caudal extent of the rNST with the most cells being located in the central portion of the nucleus, and the fewest located ventromedially and dorsolaterally. Supporting the findings of the retrograde labeling study, axons and terminals, anterogradely labeled by injecting biotinylated dextran unilaterally into the rNST (n = 4), were always found in both the ipsilateral and contralateral mPBN. Although the intensity of anterograde labeling was higher ipsilaterally, a mirror-image staining pattern consistently was present contralaterally. These results indicate that there is a substantial contralateral component of the projection from the rNST to the mPBN. This suggests that convergence of gustatory information from the two sides of the oral cavity may occur within the pons before processing in higher brain centers. These findings may have important implications as to where and how bilateral gustatory information is processed and integrated.

Neurotransmitter and neuromodulator activity in the gustatory zone of the nucleus tractus solitarius

The rostral nucleus of the solitary tract (rNST) is the first central relay in the gustatory pathway. While previous investigations have provided a wealth of information on the pattern of central terminations of gustatory afferent fibers, the morphology of synaptic connections of rNST neurons and responses of second order neurons to taste stimuli applied to the tongue, little is known regarding the neurophysiological characteristics of synaptic transmission in rNST. We have used an in vitro brain slice preparation of the rNST to study the intrinsic biophysical properties, neuropharmacology and synaptic responses of rNST neurons. These experiments have revealed that rNST neurons respond to the excitatory amino acid neurotransmitter glutamate, as well as the inhibitory amino acid neurotransmitter gamma amino butyric acid (GABA). By use of glutamate receptor agonists and antagonists we have shown that rNST neurons have AMPA/kainate and NMDA ionotropic glutamate receptors, as well as matabotropic glutamate receptors. In addition, rNST neurons respond to both GABAA and GABAB receptor agonists. The nature of the transmission at the synapse between primary afferent fibers and second order neurons in rNST has been examined by electrical stimulation of the solitary tract to elicit post-synaptic potentials (PSP). Three types of monosynaptic PSP result from stimulation of the solitary tract: excitatory post-synaptic potentials, inhibitory post-synaptic potentials, and a complex mixture of excitatory and inhibitory potentials. These new discoveries provide details about synaptic transmission in rNST and thereby clarify the underlying mechanism by which gustatory information is processed.

Relationship between structure and function of neurons in the rat rostral nucleus tractus solitarii

To investigate the relationship between the structure and function of neurons in the rostral (gustatory) nucleus tractus solitarii (rNTS), we analyzed the morphological and biophysical properties of rNTS neurons by performing whole-cell recordings in a brain slice preparation. Overall, neurons (n = 58) had a mean somal diameter of 16 microns, an average dendritic length of 598 microns, an average dendritic thickness of 0.91 microns, and a spine density of 0.037 spines/microns. Neurons were separated into three groups (elongate, multipolar, and ovoid) on the basis of previously established morphological criteria. The highest percentage (49%) of neurons were classified as ovoid, while 35% were multipolar and only 16% were elongate. The most frequently observed firing pattern, in all three cell types, elicited by a 1,200 ms, 100 pA depolarizing current pulse was a regularly firing spike train. However, the intrinsic firing properties of the remaining neurons were different. Thirty-one percent of the ovoid neurons responded with a short burst of action potentials and 44% of the elongate neurons showed a delay in the onset of the spike train following a hyperpolarizing prepulse. Less than 16% of the multipolar neurons demonstrated either of these firing characteristics. Therefore, rNTS neurons with similar morphology do not have unique biophysical properties. However, the data suggest that there may be subpopulations of the three morphological types, each of which displays a different firing pattern. Since the structure and function of the three morphological groups were not strictly correlated, these subpopulations may represent functional groups.

Preventing deep venous thrombosis in hospitalized patients

Deep venous thrombosis with subsequent pulmonary embolism remains a significant cause of morbidity and mortality in hospitalized patients. Although prophylactic treatment may reduce the incidence of deep venous thrombosis by up to 70 percent, it is estimated that only 32 percent of hospitalized patients at high risk receive adequate prophylaxis. Older patients, obese patients and patients undergoing orthopedic procedures of the lower limbs are at particularly high risk of developing deep venous thrombosis. Both mechanical and pharmacologic measures provide effective prophylaxis. Newer treatment protocols have greatly reduced the incidence of drug side effects, particularly bleeding.

Substance P excites neurons in the gustatory zone of the rat nucleus tractus solitarius

Whole-cell patch recordings of neurons in the rostral (gustatory) nucleus tractus solitarius (rNTS) were performed in a brain slice preparation from rat medulla. Neural responses to brief applications (10-45 s) of substance P (SP), via a constant superfusion apparatus, were recorded. SP transiently depolarized 80 of 117 (68%) rNTS neurons in a dose-dependent manner. Sub-micromolar concentrations of SP had potent excitatory effects, and the half maximal response occurred at 0.6 microM. The depolarizing effect of SP was accompanied by an increase in input resistance in 81% of the responsive neurons. The excitatory effects of SP persisted in low Ca2+ (0.2 mM) and high Mg2+ (12 mM) saline as well as in the presence of 2 microM TTX (n = 5 for each), suggesting direct postsynaptic action on the recorded neurons. SP also hyperpolarized 4 neurons (4%) and had no effect on 33 neurons (28%). Each of the 4 neurons which were hyperpolarized by SP showed a decrease in input resistance. A more detailed assessment of the types of neurons in the rNTS which respond to SP was also conducted. Neurons were separated into 4 electrophysiological groups on the basis of their repetitive firing pattern induced by a hyperpolarizing and depolarizing current injection paradigm. Neurons belonging to each of the 4 electrophysiological groups responded to SP. Eighteen neurons, which were filled with 1% biocytin during recording, were categorized as ovoid, multipolar or fusiform based on their morphological characteristics. SP excited all 3 morphological types of neurons in similar proportion. These results suggest that SP is an excitatory neurotransmitter in the rNTS. The effects of SP are not restricted to a particular neuron type defined either biophysically or morphologically. The implications of these results on the possible role of SP in processing gustatory and somatosensory information within the rNTS are discussed.

Transthyretin is an inhibitor of monocyte and endothelial cell interleukin-1 production

Human serum was found to contain an inhibitor of constitutive interleukin-1 (IL-1) production by human umbilical vein endothelial cells (ECs). Purification of the serum activity by anion exchange chromatography, molecular sieve HPLC, and hydroxyl apatite chromatography yielded material 82% pure with a molecular weight of 17 kDa by SDS-PAGE. Amino acid sequencing revealed the purified inhibitor to be transthyretin (TTR), a liver-derived protein. There was a 42.6% reduction in the production of spontaneous IL-1 activity in EC supernatants after coculture with 10 micrograms/ml TTR. TTR was subsequently found by ELISA to inhibit LPS-stimulated IL-1 production by cells of the human monocytic leukemia line THP-1 by 47.1 +/- 9.4%, whereas a less striking but still significant inhibition of monocyte-derived IL-1 beta production was also observed. Inhibition of IL-1 secretion correlated with increased IL-1 mRNA synthesis in both THP-1 cells and monocytes. Furthermore, TTR was associated with increased intracellular concentrations of IL-1 beta. These data suggest that TTR functions by inhibiting processing of newly synthesized peptide for secretion. This novel inhibitory effect of TTR on the production of IL-1 activity suggests a previously unrecognized endogenous antiinflammatory mediator.

Ventral pontine catecholaminergic pathway mediates the vasopressin response to splanchnic osmostimulation in conscious rats

This study examines the role of catecholamines, cell bodies and fibers of passage within the subcoeruleus area (subLC) in the arginine vasopressin (AVP) response to splanchnic osmotic stimulation and hemorrhage. Bilateral chemical lesions were induced into the subLC, approximately 1 mm ventral to the locus coeruleus (LC), using 6-hydroxydopamine (6-OHDA) and ibotenic acid to selectively destroy catecholaminergic components and cell bodies, respectively. Vehicle and 5,7-dihydroxytryptamine (5,7-DHT) injections into the subLC area, 6-OHDA injections into the LC, as well as systemic desipramine pretreatment, were performed as controls for the possible non-specific effects of the lesions. Seven and 8 days later, plasma AVP level, plasma osmolality, mean arterial pressure and heart rate were measured following either gastric infusion of hypertonic (598 mOsm/kg; 2 ml/4 min) or isotonic (290 mOsm/kg) saline or a mild hemorrhage (2.5 ml/300 g) in conscious rats with indwelling tail artery catheters and naso-gastric tubes. 6-OHDA injections into subLC reduced the AVP response to the osmotic stimulation by 62.3% (P less than 0.01), as compared to vehicle-injected controls. These same rats demonstrated a normal AVP response to hemorrhage implying a specificity of the disrupted pathway. All controls confirmed that the effects of the 6-OHDA were due to specific action on noradrenergic components within the subLC area. Ibotenic acid lesions in the subLC did not significantly decrease the AVP response, demonstrating that mainly fibers and not cell bodies in this region are part of the pathway. 6-OHDA injections just anterior to the LC, where the dorsal noradrenergic bundle (DNAB) forms, reduced the AVP secretion due to hemorrhage by 77.0% (P less than 0.05), but had minor effects on the response to osmotic stimulation. These results indicate that catecholaminergic fibers travelling primarily within the subLC, in the ventral noradrenergic bundle (VNAB), carry splanchnic osmotic input to the hypothalamus, whereas the DNAB may mediate the AVP response to hemorrhage.

Central neural pathway mediating splanchnic osmosensation

To determine the central neural pathway which carries splanchnic osmosensory information to vasopressin (AVP) neurons in the hypothalamus, bilateral electrolytic lesions were placed in the ascending catecholaminergic fiber bundle, the locus coeruleus (LC), the locus subcoeruleus (subLC), the lateral parabrachial nucleus (LPB), the caudal periaqueductal gray (PAG) and the median preoptic nucleus (MPO). Six and seven days later, plasma AVP levels, plasma osmolality, mean arterial pressure and heart rate were measured following gastric infusion of hypertonic (598 mosm/kg; 2 ml/4 min) or isotonic (290 mosm/kg) saline in conscious rats with indwelling tail artery catheters and nasogastric tubes. The most effective pontine lesions, which were located in the ventral locus subcoeruleus (vsubLC) approximately 1.0 mm below the LC, decreased the AVP response to hypertonic gastric infusion by 59.7% (P less than 0.05) as compared to sham-lesioned controls. In addition, unilateral vsubLC lesions dramatically reduced the catecholamine innervation of the ipsilateral paraventricular nucleus (PVN), as qualitatively determined with dopamine beta-hydroxylase immunocytochemistry, suggesting that a pathway ascending with catecholaminergic fibers was disrupted. Lesions of the MPO were also very effective, decreasing the AVP response to hypertonic saline infusion by 60.3% (P less than 0.05), suggesting that the MPO is an integral relay center in this pathway. On the other hand, LC, LPB and PAG lesions were ineffective. Systemic plasma osmolality or cardiovascular factors did not mediate the AVP response. These results demonstrate, for the first time, that splanchnic osmotic information is transmitted to the hypothalamus via pathways within the ascending catecholaminergic fiber bundles, the MPO is a relay center where peripheral and central osmotic information may be integrated, and the LC, LPB, and PAG are not part of the splanchnic osmotic pathway.

The role of intracellular messengers in adrenocorticotropin secretion in vitro

Adrenocorticotropin (ACTH), an opiomelanocortin peptide, is secreted from anterior pituitary corticotrophs upon stimulation with corticotropin-releasing hormone (CRH), arginine vasopressin (AVP) and several other neuropeptides. CRH, the most potent secretagogue of ACTH, stimulates ACTH secretion and biosynthesis by increasing the production of cyclic adenosine 3',5'-monophosphate (cAMP) within corticotrophs. AVP, which is a weak secretagogue of ACTH but strongly potentiates CRH-stimulated ACTH secretion, operates through the phosphatidylinositol (PI) transduction pathway. Both CRH and AVP increase cytosolic free [Ca2+] within normal corticotrophs indicating a role for Ca2+ in ACTH secretion. Glucocorticoids inhibit ACTH synthesis by suppressing transcription of the proopiomelanocortin (POMC) gene and attenuate ACTH release by decreasing cAMP accumulation stimulated by CRH. This review focuses on the roles of these intracellular messengers in ACTH secretion from normal anterior pituitary cells in vitro, and discusses the possible interactions between the cAMP, calcium and PI transduction pathways. Future areas of research are suggested such as identification of protein substrates of cAMP-dependent and Ca2(+)-dependent kinases within normal corticotrophs and evaluation of their role in ACTH biosynthesis and secretion.

Physiological concentrations of atrial natriuretic factors with intact N-terminal sequences inhibit corticotropin-releasing factor-stimulated adrenocorticotropin secretion from cultured anterior pituitary cells

The effectiveness of atrial natriuretic factors (ANFs) as inhibitors of CRF-stimulated ACTH secretion was examined in cultured rat anterior pituitary cells. alpha ANF-(1-28) significantly inhibited ACTH release stimulated by 1-5 nM CRF. At the most effective concentration of 100 pM, alpha ANF-(1-28) inhibited ACTH release by 40.1% (P less than 0.001). This effect was manifested after 3 h, but not after 0.5 or 1 h, of incubation, suggesting that ACTH synthesis may have been reduced. Conversely, alpha ANF-(5-28), at concentrations of 10 pM to 10 nM, had no effect on ACTH secretion after 0.5, 1, or 3 h. alpha ANF-(1-11) weakly inhibited ACTH secretion at concentrations of 100 and 1000 pM. Again, these effects were observed after 3 h, but not after 0.5 or 1 h, of incubation. These results suggest that ANF-induced inhibition of CRF-stimulated ACTH release requires 1) an intact N-terminal sequence of the ANF peptide, 2) low concentrations, and 3) more than 1 h of incubation. The results explain previous negative evidence and suggest that alpha ANF-(1-28) may be a physiological inhibitor of ACTH secretion.

Acetylcholine activates cerebral interneurons and feeding motor program in Limax maximus

The cellular and network effects of acetylcholine (ACh) on the control system for feeding in Limax maximus were measured by intracellular recordings from feeding command-like interneurons and whole nerve recordings from buccal ganglion motor nerve roots that normally innervate the ingestive feeding muscles. The buccal ganglion motor nerve root discharge pattern that causes rhythmic feeding movements, termed the feeding motor program (FMP), was elicited either by attractive taste solutions applied to the lip chemoreceptors or by ACh applied to the cerebral ganglia. The ability of exogenous ACh applied to the cerebral ganglia to trigger FMP was blocked by the cholinergic antagonists curare and atropine. If the strength of the lip-applied taste stimulus was in the range of 1-2 times threshold, cerebral application of the cholinergic antagonists blocked or greatly decreased the ability of lip-applied taste solutions to trigger FMP (5 of 8 trials). The cerebral feeding interneurons, some of which activate FMP when stimulated intracellularly, are excited by small pulses of ACh applied directly to the cell body from an ACh-filled micropipette. A pulse of ACh that activates several of the feeding interneurons simultaneously triggers FMP. The data suggest that under certain stimulus conditions an obligatory set of cholinergic synapses onto the feedininterneurons must be activated for taste inputs to trigger ingestion. The determination of ACh's action within the feeding control system is necessary for understanding how enhanced cholinergic transmission leads to prolonged associative memory retention (Sahley, et al., 1986).

Biliary-tract disease in Malaya

A review was carried out of the pattern of biliarytract disease in Malaya where the population consists of three major groups: Malays, Chinese, and Indians. The review was based upon (a) a study of the comparative incidence of operations for biliary disease in the six large general hospitals serving West Malaya, and (b) a more detailed study of 120 consecutive patients undergoing operations on the biliary tract in the University Hospital, Kuala Lumpur.

Biliary-tract disease requiring operation is common in Malaya, and appears to be more common in Indians and Malays than in the Chinese.

Two distinct patterns of biliary-tract disease are encountered. The majority (two-thirds) of the patients have a disease similar to the Western type of cholelithiasis, but the remaining one-third have a disease, ‘Oriental cholangitis’, of a distinctly different pattern, with a different sex ratio, a high incidence of infected bile, and the almost invariable presence of jaundice and soft stones in the common duct.

Oriental cholangitis was found in Chinese, Indian, Malay, and Aborigine patients in this survey, and is not, therefore, confined to the Chinese and Japanese as previously suggested.

A MEDICAL CURIOSITY: PIGMENTED NEVUS-WITH CASE REPORT

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