Mark Corson

By W. Volkar. Queens College. 2018.

The esophagus and crop produce mucus order 100 mg kamagra flavored fast delivery, which softens and moisturizes the food in preparation for mechanical and chemical digestion lower in the gastrointestinal tract cheap 100 mg kamagra flavored. Initial stages of carbohydrate digestion (mediated by salivary amy- lase) may occur in the crop of some species buy cheap kamagra flavored 100 mg on line. The bird was in overall good having a large cervical component and two thoracic condition and would regurgitate when handled by either of the components. The bird would flick its head when it regurgitated, causing vomitus to land on the head feathers giving and the muscular crop is the main site for the me- them a stiff, displaced appearance. Adult pigeons of both genders produce a secretion called crop milk that is regurgitated and fed to the tation or vomiting. Other accompanied by a rapid flick of the beak, which fre- food items gradually replace the crop milk as the quently deposits vomitus on top of the bird’s head babies mature. A history of recent drug administra- crop milk, which consists of desquamated cells of the tion, assisted feeding, poor hygiene or access to toxic proliferated stratified squamous epithelium of the compounds may suggest an etiology for esophageal crop. Wetting of the feathers finches may also produce some secretions that are will help in visualizing lacerations, discolorations or regurgitated and fed to neonates. Hypermotility or hypomotility Penguin feeds its chicks a fluid produced by may occur with crop disorders. Regurgitation is a common courtship be- The esophagus and crop are thin-walled structures havior in some psittacine birds, particularly budgeri- that are difficult to palpate unless abnormally thick- gars, cockatiels and macaws. The crop can be palpated when it species (eg, pigeon, Great Bustard, ostrich, Sage is full of food, fluid, air or abnormal masses. An Grouse) have inflatable esophageal diverticula that enlarged crop with a dough-like consistency that fails act as resonating chambers or display devices. Occasionally, large deposits of fat, and in Investigative Methods some cases lipomas, can occur near the crop and should not be misdiagnosed as a full or impacted Clinical signs of esophageal or ingluvial disorders crop. Discolored necrotic areas, swelling and plicator into the esophagus, and moving it up and edema are common clinical findings. The cotton tip is then compressed between the thumb and For diagnostic purposes, an esophageal or ingluvial index finger to produce one drop of fluid, which is aspirate can be obtained by inserting a catheter and placed on a slide for direct examination. A clinical washing the mucosa with sterile isotonic saline solu- diagnosis in Psittaciformes can be difficult because of tion. Luer-lock syringes should always be used when low parasite numbers in the early stages of the dis- tube-feeding or collecting samples from psittacine ease137 and the intracellular location of the parasite. Immediate microscopic examination of a wet mount Trichomoniasis can cause inflammation of the upper slide is best for diagnosing trichomoniasis. Material intestinal tract and mouth resulting in dysphagia or aspirated from the crop should be centrifuged, and vomiting, and may be an underdiagnosed cause of microscopic examination of the sediment may reveal ingluvitis in budgerigars. Air-dried smears can be stained with Diff- plaques and papilliform projections in the esophagus Quik, Gram’s stain, Wright’s stain, Hemacolor or and crop have been defined in many budgerigars. Flotation is more likely to detect low concentra- gus was most frequently affected, but many birds tions of eggs than a direct smear. Histologic examination for examining the gastrointestinal mucosa and for revealed that the increased thickness of the crop and removing some foreign bodies (Color 19. The intracellular occurrence of tricho- Diseases of the Esophagus and Crop moniasis has not been reported in other avian gen- era, and this unique feature of infection in budgeri- Trichomoniasis gars may contribute to the underdiagnosis of Trichomonas gallinae infections commonly occur in trichomoniasis as a cause of morbidity and mortality pigeons and raptors, and may also occur in Passeri- in Psittaciformes. Clinical signs included necrotic der- matitis at the commissure of the beak, depression, Anatomic Location Esophagus, crop Mouth, cloaca, umbilicus, liver, generalized crop stasis and white caseous plaques on the tongue and pharynx. The bird had been in this environment sented with a six-month history of intermit- off and on for several years. Abnormal clini- tent dyspnea that had become progres- cal pathology findings included sively worse. Ra- a soft tissue mass in the area of the caudal diographs indicated a rough appearance to thoracic esophagus. Laparoscopy indicated the dorsal serosal surface of the proven- a diffuse air sacculitis (that was not de- triculus, suggestive of inflammation. The tected on radiographs), and the soft tissue client chose to treat the bird at home with mass was determined to be a dilated por- only antibiotics. At necropsy, a large per- trachea revealed thick mucus from which forating ulcer was present in the proven- Klebsiella spp. The bird responded to systemic antibiotics but would relapse with the ces- Color 19. The etiology of the mass Several different nematodes can cause remains undetermined. Necropsy findings included hyper- koilin layer (dark green areas), which can emia of the intestinal tract with distended partially extend into the proventriculus. The bird did A mature Yellow-collared Macaw hen died not respond to supportive therapy. Histo- following a period of unseasonably low tem- pathology indicated marked myocardial de- peratures well below freezing. The bird had generation and necrosis of undetermined exhibited several days of depression before etiology. At necropsy, the cloaca and lower intestinal tract were filled with blood- Color 19. Histopathol- A mature Scarlet Macaw was presented for ogy indicated severe necrosis of the villi and intermittent regurgitation and weight loss. Several masses (inglu- The pericloacal area of birds is normally violiths) were palpated and were removed dry and the feathers are of normal color. Accumulations of excrement or bile-stained feathers are indications of enteritis or cloa- Color 19. The crop cockatiel had biliverdinuria from hepa- was severely distended with food, and the topathy and enteritis associated with bird had an audible click on inspiration. Five percent acetic acid will cause papil- gastrointestinal tract was dilated and con- tained poorly digested ingesta.

On palpation order kamagra flavored 100mg overnight delivery, lipomas are usually well defined and soft; the overlying skin is freely Lipomas usually arise in the subcutis of the sternal 143 mobile kamagra flavored 100 mg sale. On cut surface kamagra flavored 100 mg for sale, they are may occur in the thoracoabdominal cavity (arising thinly encapsulated and fatty. Histologically, lipomas from thoracic or mesenteric fat, ovary, ventriculus appear as thinly encapsulated masses composed of and liver) or in association with skeletal mus- lobules of well differentiated adipocytes. Central necrosis may Hibernoma: A hibernoma is a rare benign tumor of be present in larger masses, especially those neo- brown fat origin. A subconjunctival hibernoma was plasms that grow rapidly or are subjected to trauma. The neoplasm involved the ventrolateral as- Dietary changes and increased exercise are fre- pect of the right sclera and protruded through the quently curative in early cases and should be imple- palpebral fissure, interfering with eyelid closure. Because lipomas are often accompanied by Histologically, neoplastic cells stained faintly eosino- body fat that may interfere with caudal air sac vol- philic, appeared foamy, had central-to-paracentral ume, exercise programs should be initiated with nuclei and had a voluminous cytoplasm containing care, especially in tachypneic patients. Surgical exci- numerous, fine vacuoles and birefringent eosino- sion is necessary if the tumor is causing clinical philic material. The neoplasm was well vascularized problems that are not resolved with diet change and and contained a delicate stromal framework. Feeding formu- Xanthoma/Xanthomatosis: The term xanthoma lated diets should prevent goiter and may also reduce means “yellow mass. Non-spe- neoplasm, but an inflammatory intumescence result- cific use of thyroxine should be avoided, and treat- ing from the accumulation of lipid-laden macro- ment of lipomas in the absence of hypothyroidism is 66,113 phages, giant cells, free cholesterol and variable de- not an indication for thyroxine administration. Xanthomas occur frequently in Myelolipoma: Myelolipomas are composed of adipose gallinaceous and psittacine birds, appearing as yel- and hematopoietic tissues that may arise in the sub- low, single-to-multiple, discrete subcutaneous nod- cutis of the trunk, wings and legs. Occasionally they ules or diffuse thickenings of skin that may be may occur in the liver or spleen. The outward appear- featherless, ulcerated or hemorrhagic (Color ance is similar to a lipoma. Multicentric origin or widespread metastasis is tion and fibroplasia give rise to the nodular or tumor- typical. Unresectable or multiple skin xanthomas may respond to irradiation Histologically, neoplastic cells appear spindle-like, (low-energy X-rays; 20 to 30 Gy) or hyperthermia. Cell nuclei are round to Dietary restriction of oily seeds may be beneficial in oval and contain multiple nucleoli. Alternatively, osmi- myxosarcoma and myxoma) arise from the prolifera- cated tissue specimens may be processed routinely tion of fibroblasts or undifferentiated mesenchymal and stained with hematoxylin and eosin. In these cells, which frequently assume a spindle-like appear- latter tissue sections, osmicated lipid will appear ance. In myxosarcomas, neoplas- mas occur commonly in budgerigars, cockatiels, macaws and parrots. Superficial fibrosarcomas may be covered by an intact-to-ulcer- ated epidermis accompanied by hem- orrhage and secondary bacterial in- fections. Fibrosarcomas commonly arise from the soft tissues of the wing, leg, head, beak, cere and trunk ( Co l or 25. Physical examination revealed are locally invasive and may eventu- numerous masses throughout the body that were confirmed by radiographs. Histopathol- ally metastasize, especially to the ab- ogy indicated an invasive fibrosarcoma involving the soft tissues and bones of the head (courtesy of Jane Turrel). Fibroma: A fibroma is an uncommon benign neoplasm composed of well differentiated fibroblasts distributed within a collagenous matrix. Radiographically, a large, uniform, soft tissue mass with mas are firm on palpation and may osteolysis involving the humoral head and diaphysis was noted. The increased medullary arise almost anywhere, but usually bone density was considered normal for a laying hen. Cytology of a fine-needle aspirate confirmed fibrosarcoma (courtesy of Marjorie McMillan). Metastasis may occur, but is infrequent mas are characterized by epidermal ulceration and to rare. These cells are scattered singly or arranged in Reactive Fibroplasia: Granulation tissue exempli- nests and cords. Laminated keratin pearls may be may be highly vascular and proliferative with vari- observed within epithelial cell cords in companion able degrees of inflammation. The etiology of multifocal, tissue may have a proliferative or neoplastic-like dermal squamous cell carcinoma of chickens has not appearance. Inflammatory cells may be admixed Uropygial Gland Adenoma and Adenocarcinoma: with blood. Histologically, tissue architecture is a Uropygial gland neoplasms occur sporadically in cap- differentiating feature of the lesion wherein blood tive birds, especially budgerigars and canaries. Neoplasia must be distinguished from adeni- plasia with granuloma formation also may be ob- tis, which usually requires histologic examination. In such instances, nematode-induced reac- tive fibroplasia may be difficult to distinguish from Feather Folliculoma: Feather folliculomas occur pri- 57,62 marily in canaries and budgerigars. Microscopically, these lesions appear eous papillomas are observed occasionally in domes- multilobulated and are lined with irregular, hyperplas- tic, captive and free ranging birds. Basal ple papillomas most frequently originate from the skin cells are arranged in barb ridges and undergo abrupt of the eyelids, at the junction of the beak and face, and squamous differentiation in the center of the mass, forming laminations of free keratin. The anatomic location of these benign neoplasms may interfere with vision, prehen- Miscellaneous Basal Cell Tumors and Cutaneous sion of food or perching if the lesions are severe (Color Cysts: All of these neoplasms present as discrete skin 25. Basal cell tumors are composed of sheets, hyperplastic stratified squamous epithelium over a fi- nests or cords of basaloid epithelial cells. Cutaneouspapillomas are viral-in- population does not exhibit terminal cellular or struc- duced, at leastin African Grey Parrots, Chaffinchesand 5,25,108 73,87,96 tural differentiation.

Hunter stressed first the need for a flexible approach to fitting of the standard curve discount kamagra flavored 100mg mastercard. The program by Raab and McKenzie1 already mentioned could make use of a fifth parameter providing for asymmetry of the fitted logistic curve buy kamagra flavored 100 mg otc. He agreed that the fitted curve should not depend on data from one assay alone purchase kamagra flavored 100mg with amex, but rather on experience accumulated over, say, ten or more assays with the analyte and system concerned. With regard to precision profiles, he stressed that they expressed only one aspect of assay quality, namely precision, and gave no indication of accuracy. Recovery studies, performed by adding the same standards to analyte- free samples provided an additional important means of quality control. While programs such as that of Raab and McKenzie could not be run on existing popular microcomputers, the diminishing costs of hardware would make the needed facilities increasingly available. Referring to computer-generated confidence limits based on imprecision profiles, he considered that as long as these were recognized as estimates of imprecision, not inaccuracy, their utility remained. It was pointed out that in some circumstances, for example in pharmacokinetic studies, utilization of a wider region might in any case be desired. Ekins was of the opinion that the only acceptable way to express the working range of an assay was as the range over which its results were acceptable as judged from its precision profile. It might, for example, be possible to double the working range of an assay by washing precipitates and thus improving precision at the upper limit of the range. Rodgers agreed that the placement of standards was a difficult statistical problem. The importance of data processing in relation to assay design and optimization was stressed by several speakers. Rodgers recalled in this regard the dictum of Finney that the sophistication of data processing should be even greater when assays were being set up. Programs now existed for the design and optimization of assays on the basis of their imprecision profiles. Ekins considered that the lack of such programs had been a major obstacle to the development of effective assay techniques. Schwarz expressed the view that available programs were still insufficient, in that they did not give due regard to physico-chemical aspects of assay performance through Scatchard plots, Sips-Hill analyses etc. Another speaker emphasized that the facilities provided by most commercially available counting systems with on-line data processing, as well as the reagents provided by most commercially available assay kits, were inadequate for proper quality control. Standardization of reagents was also recognized as an important aspect of quality control, several speakers referring to the need to examine individual assay data from chemical and biological standpoints before processing them. The results of data processing could be misleading unless assays were carried out under adequate conditions in this regard. Procedures for rejection of outlier measurements evoked some discussion, the distinction being drawn between outliers arising from poor reproducibility between replicate measurements and outliers with good reproducibility but showing otherwise unexpected behaviour, for example nonconformity with a standard curve. Rodgers and other speakers stressed that outlier rejection schemes should be employed with caution; it was sound policy not to reject outliers without good reason. The intractable problem in this regard was recognized as the unknown sample with good reproducibility between replicates but an erroneous mean result due to a mistake in technique. A speaker drew attention to the importance of training technicians in data- processing aspects of assay quality control and to the need for a manual for this purpose. Essential is an experienced assayist, able to develop his own assays or else to modify (“adjust”) even commercial reagents (kits) that render the fruitless adjustment of data no longer necessary. I would prefer to sub­ ordinate this lecture to an imperative and purposeful interpretation. The consequences that follow are that assay improvement requires action which means that the object of action must be the assay with everything appertaining to it (and not the data only! One gets the assay one deserves; the assay can only give what it has received before! Regarding the latter points, one needs to consider that, besides the final analyte estimate, it is essential to obtain information regarding the inherent quality or specific deficiency of an assay in work. That such information can acquire the quality that is subsequently convert- able into an action towards the elimination of such deficiencies, in principle forbids any (computerized) “adjustments”. Already at this stage this alludes to the danger of concealing such a message when applying iterative, sophisticated data-reduction algorithms. Information is only of value when it is presented and respected in its originality. Working range The working range is generally not wider than six logarithmically-to-the-base-2 diluted standard points covering a range from 1 to 32 concentration units per tube. Even if in a particular assay the standards (usually in buffer) may occasionally “work” outside this range, no guarantee can be given that this also holds for unknowns since, being in plasma matrix or solvent extract, they may not behave identically in this area of “uncertainty”, as can be easily shown by parallelism experiments. As depicted in Figs 2A & B, these constraints in reliable operability are independent of the method of chosen data analysis. And while it may be possible to “trim” the working range upwards and down­ wards (or shift the calibration curve to the right or the left, respectively) by changing reagents or incubation conditions, or both, one may still be unable to override the constraints of maximally 6 logarithmic standard dilutions covering either 0. Assay specificity and precisionare often found to be incompatible with each other. We believe that this is a valid approach that is intelligible and directly visible from the calibration curve and that —when accepted —can rule out a number of problems in curve-fitting theory, especially with respect to an over-punctilious accounting for heteroscedasticity. Immoderate expectations regarding the working range are, I feel, also a major reason for many proposals of extravagant data analysis methods. And one should not despair if one never reaches the upper theoretical limit of assay quality (Fig. It is, however, more important to maintain forever a moderate level of performance (stability) than to enjoy the highest quality for only a very short time. We can be certain to find at least “local consistency” and reproducibility including physiopathological plausibility as a result of stability. This can be considered as a moderate and thus realistically achievable as well as long-term maintainable goal (Fig.

It is equal to the quantity of uncertainty by which any clinical chemistry measurement is tacitly regarded generic 100 mg kamagra flavored amex. Therefore kamagra flavored 100mg lowest price, it is unnecessary to report any type of confidence limits at all to the clinician kamagra flavored 100 mg with amex. However, the assayist must have made the decisions regarding whether or what to report on the basis of daily and complete quality control in order to assess the reliability prior to reporting. This program represents the final state of five years’ daily experience and challenge in the author’s laboratory. A complete documentation, step-by-step operation manual, and program listing is available to scientists upon request. In addition, programs for Scatchard-plot analysis, Sips-Hill plots, and kinetic experiments in binder-ligand studies have been created and published. The community which we have to serve by clinical diagnosis and scientific research has a right to it. R e s u lt o f th e F e d e ra l G erm a n E x te r n a l Q u a lity C o n tro l S u rv e y fo r C o rtis o l a n d u n c o n ju g a te d e strio l in O c to b e r 1 9 8 1. The pluralistic argument according to which an unintelligible variety of methods is desirable, is definitely invalidated. The expectation that from this variety the optimal method will automatically emerge on “day X” like a phoenix is identified as naive. Wick, Head of the Institute of General and Experimental Pathology, University of Innsbruck, Austria, is gratefully acknowledged. Wolak, the author’s attempts towards quality control and standardization would have had little chance to become realized. P r a c t i c a l a p p l i c a t i o n s o f ra d io im m u n o a s s a y t h e o r y. A s im p le p r o c e d u r e y i e l d i n g l i n e a r c a l i b r a t i o n c u r v e s , C l i n. P r o d u c tio n a n d c h a r a c t e r i z a t i o n o f m o n o c lo n a l a n t i ­ b o d ie s a g a i n s t b o v in e l u t e i n i z i n g h o rm o n e , Im m u n o b io lo g y 160 (1 9 8 1 ) 1 9 6 -2 0 7. The e n d o c r in e t a r g e t c e l l a s a q u a n t a l r e s p o n s e u n i t : a g e n e r a l c o n t r o l m e c h a n ism , A dv. H orm one b in d in g g l o b u l i n l e v e l s in p a t i e n t s w ith h e r e d i t a r y a n g io o e d e m a d u r in g t r e a t m e n t w ith D a n a z o l.. I n t e r f e r e n c e o f D a n a z o l w ith th e ra d io im m u n o a s s a y o f s t e r o i d h o rm o n e s , J. M ic r o p r o c e s s o r - b a s e d ra d io im m u n o a s s a y d a t a a n a l y s i s , "M e th o d s i n E n zy m o lo g y " , A cad em ic P r e s s , New Y ork ( 1 9 8 1 ) , v o l. P r i n c i p l e s o f p r o t e i n b in d in g a s s a y s ( s a t u r a t i o n a n a l y s e s ). Schwarz’s insistence that the quality control of an assay must begin with its design and validation. He had reservations, however, about the definitions of various terms in the paper — notably those of avidity and sensitivity —which did not fully conform with the generally accepted ones and might, in his view, lead to confusion. A speaker made the comment that the design of an assay should not be changed solely to simplify the processing of its data. Assays should be designated to fulfil clinical requirements and should be optimized according to these require­ ments. If an assay gave results which were acceptably reproducible and unbiased but which could not be fitted by a given curve-fitting program, the program should be changed, not the assay design. Ekins emphasized that the optimiza­ tion of an assay, particularly as regards the choice of such parameters as Ab and *Ag concentrations, should be aimed at the minimization of statistical errors in measurement. He added that linearity of the logit-log plot was not a necessary property of the good assay. Indeed, if large amounts of Ab were used and Ab binding sites were not saturated, such linearity would not be observed. Schwarz indicated that the relevant modifications in assay design described in his paper had in fact been aimed at the improvement of assay performance. He also agreed that assay design should not be compromised to suit the needs of data processing, particularly by methods as crude as the two-parameter logistic (logit-log). It was much more satisfactory to use the four-parameter logistic or some other more advanced method to obtain a smooth relationship representing the data. The Scatchard plot, in his view, had little or no place in the optimization of assay design. The preferred way to perform such an analysis was to use a good non-linear regression package to fit an appropriate model directly to the raw data. In his experience, data obtained from studies with radioactive tracer in the absence of unlabelled analyte gave good plots which were a sufficient guide to the bfehaviour of unlabelled analyte in the system. Rodgers disputed this, maintaining that alternative methods of study would give much more reliable results. Rodgers emphasized that both imprecision and bias contributed to the inaccuracy of results. Ekins agreed that between-assay confidence limits were the most appropriate to clinical practice. Rodgers stressed, however, that the comparison of results from different laboratories required the use of between-laboratory limits, which would be larger. Hunter indicated that between-laboratory coefficients of variation might still be much smaller than suggested by Mr. Several speakers questioned what action should be taken if the results on samples of one or more quality control pools in an assay were found to be anomalous. There was agreement that such a situation could only be resolved in the light of clinical requirements and of accumulated quality-control experience with that type of assay.

In some cases sleep apnea occurs even if no airway obstruction or snoring is present order 100 mg kamagra flavored visa. This form purchase 100mg kamagra flavored with amex, called central sleep apnea generic kamagra flavored 100mg with visa, is caused by a loss of brain control over breathing. In both obstructive and central sleep apneas, obesity is the major risk factor, and weight loss is the most important aspect of long-term management. In this procedure, the patient wears a mask over the nose during sleep, and pressure from an air blower forces air through the nasal passages. The air pressure is adjusted so that it is just enough to prevent the throat from collapsing during sleep. Surgery to reduce soft tissue in the throat or soft palate should be used only as a last resort because it often does not work or can make the problem worse. In this procedure lasers are used to surgically remove excessive soft tissue from the back of the throat and from the palate. This procedure works well initially in about 90% of sleep apnea sufferers, but within one year many people are the same as or even worse than before because of the scar tissue that invariably forms. Therapeutic Considerations Adequate sleep is absolutely necessary for long-term health and regeneration. However, chronic sleep deprivation appears to accelerate aging of the brain, cause neuronal damage, and lead to nighttime elevations in cortisol. The average American consumes 150 to 225 mg caffeine per day, roughly the amount of caffeine in one to two cups of coffee. Although most people can handle this amount, there is a huge variation in the rate at which different people detoxify stimulants such as caffeine. Owing to the genetic variation in the liver enzyme that breaks down caffeine, some people can eliminate caffeine very quickly (for example, half of a dose of caffeine is eliminated within 30 minutes), while in others the breakdown process is much less effective (it can take as much as 12 hours to eliminate half of a dose of caffeine). Everyone who drinks more than one cup of coffee in the early morning and who has trouble sleeping should simply try caffeine avoidance for 7 to 10 days. All sources of caffeine—not just coffee but tea, chocolate, drugs with caffeine, and energy drinks—must be avoided. Exercise Regular physical exercise is known to improve general well-being and promote improvement in sleep quality. Usually 20 minutes of aerobic exercise at a heart rate between 60 and 75% of maximum (with the maximum rate calculated as 220 minus the patient’s age in years) is sufficient. Progressive Relaxation Numerous techniques can promote relaxation and prepare the body and mind for sleep. One of the most popular and easy-to-use techniques is progressive relaxation, in which an individual is taught what it feels like to relax by comparing relaxation with muscle tension. Each muscle is contracted forcefully for a period of one to two seconds, then relaxed. The procedure begins with contraction and then relaxation of the muscles of the face and neck; next the upper arms and chest are contracted and then relaxed, followed by the lower arms and hands. The process is repeated progressively down the body—abdomen, buttocks, thighs, calves, and feet. Because the procedure goes progressively through all the muscles of the body, a deep state of relaxation eventually results. Nocturnal Glucose Levels Dips in blood glucose levels during the night may be an important cause of sleep-maintenance insomnia, especially when the drops are rapid. The brain is highly dependent on glucose for energy, and a quick drop in blood glucose level stimulates the release of adrenaline and cortisol, which promote awakening. Serotonin Precursor and Cofactor Therapy Serotonin is an important initiator of sleep. The synthesis of serotonin in the central nervous system depends on availability of the amino acid tryptophan. Although not every patient has shown response to tryptophan in clinical trials, those who do respond have experienced dramatic relief. The key advantage of tryptophan over prescription and over-the-counter pills is that, unlike these agents, tryptophan does not produce any significant distortions of normal sleep processes. Current knowledge about the sleep-inducing effects of tryptophan suggests that it is generally more effective in sleep-onset insomnia and less effective in sleep-maintenance insomnia. For example, administration of large dosages of tryptophan causes a massive elevation of plasma melatonin concentration. In one double-blind study, the effects of 3 g tryptophan on sleep performance, arousal threshold, and brain electrical activity during sleep were assessed in 20 men with chronic sleep-onset insomnia. However, on nights four through six, the time it took to fall asleep was significantly reduced. Consistently with other studies, this study found that unlike sleeping pills (especially benzodiazepines), tryptophan did not alter sleep stages, impair daytime performance, or alter brain electrical activity during sleep. This study suggests that tryptophan should be used for a minimum of one week before its effects can be assessed in chronic insomnia. However, single dosages of tryptophan can have good sleep-promoting effects in other situations, such as in people who regularly experience insomnia the first time they sleep in a new place, such as a hotel. Administration of high-dose tryptophan (4 g) during the day can cause daytime sleepiness. This suggests that consumption of foods high in tryptophan during the day may contribute to daytime sleepiness.