Signs Of Secretion Research Articles

Ultrastructure of the secretory endometrium during oestrus in young maiden and foaled mares

Cyclical accumulation of uterine fluid occurs during oestrus and is often seen in excessive volumes in mares considered susceptible to endometritis. Since the mechanisms behind the formation of free uterine fluid remain to be clarified, the fine structure of the secretory equine endometrium was studied in biopsies collect during videoendoscopy from 14 endometritis-free, 4-9-year-old mares during oestrus. A distinct oedema of the tunica mucosa was evident. The surface epithelium had both ciliated and nonciliated cells and, particularly at the uterine body, often presented intra-epithelial macrophages. The epithelial cells of the gland duct were similar to the surface epithelium, except that the nonciliated cells lacked secretory vesicles in the non ciliated cells. This glandular epithelium presented clear signs of secretory activity with conspicuous secretory vesicles holding electron-dense granula in the adluminal cytoplasm and a well developed supranuclear Golgi apparatus. Secretory products as well as cell debris were commonly found in the lumen of the glands. No clear signs of apocrine secretion were found and it seemed therefore, that the mechanism of secretion is merocrine, i.e. by exocytosis. The endometrial oedema and intense secretory activity, both under oestrogenic influence, contribute to the building up of the uterine fluid during oestrus. No differences in morphology of the secretory endometrium could be noticed between nulliparous mares and mares that had had 1 or 2 foals.

Increased secretion of 32,33 split proinsulin after intravenous glucose in glucose‐tolerant first‐degree relatives of patients with non‐insulin dependent diabetes of European, but not Asian, origin

The aetiology of non-insulin dependent diabetes is unknown, but defective insulin secretion is a feature. The disease also has a strong genetic basis and first-degree relatives of patients have an increased risk of future diabetes. To investigate whether beta-cell dysfunction is an early feature of the disease, we studied insulin secretion in healthy first-degree relatives of patients with non-insulin dependent diabetes. Each subject underwent a 1-hour intravenous glucose tolerance test (0.3 g/kg). Seventeen first-degree relatives of patients (10 of European and 7 of Asian (Indian subcontinent) origin) with normal glucose tolerance were compared with 17 matched control subjects with no family history of diabetes. Plasma immunoreactive insulin (IRI) was measured by radioimmunoassay, and specific insulin, intact and 32,33 split proinsulin were measured by specific immunoradiometric assays (IRMA) for the 1st phase (0-10 minutes) and 2nd phase (10-60 minutes) responses. Glucose and intermediary metabolites were measured enzymatically. Fasting concentrations of IRI, IRMA insulin, intact and 32,33 split proinsulin were similar in relatives and controls in each group. Fasting glucose levels were similar in European relatives and controls but lower in Asian relatives compared to their controls (mean +/- SE 4.9 +/- 0.2 vs 5.5 +/- 0.2 mmol/l, P < 0.05). Following intravenous glucose, European relatives had similar IRI and glucose levels to their controls. Secretion of 32,33 split proinsulin was increased in European relatives compared to their controls, significantly so for 2nd phase secretion (1st phase median (range): 71 (7-352) vs 55 (17-118) pmol/l min, NS; 2nd phase: 433 (115-1459) vs 234 (55-745) pmol/l min, P < 0.05). Secretion of IRMA insulin and intact proinsulin were similar in European relatives and controls (IRMA insulin: 1st phase 2757 (700-10,969) vs 2830 (632-4682) pmol/l min; 2nd phase 6387 (3006-15,865) vs 5284 (2060-18,605) pmol/l min; intact proinsulin: 1st phase 31 (13-113) vs 32 (16-72) pmol/l min; 2nd phase: 174 (87-737) vs 159 (97-298) pmol/l min). European relatives had a greater percentage of proinsulin-like molecules (intact + 32,33 split proinsulin) to total insulin (sum of IRMA insulin + intact + 32,33 split proinsulin) during the 2nd phase of secretion (9.1 (5.0-11.8) vs 5.9 (4.3-12.6)%, P < 0.05). In contrast, Asian relatives had similar secretion of IRI, IRMA insulin, intact and 32,33 split proinsulin to their controls. Glucose disappearance (KG) was similar in relatives and controls within each ethnic group (Europeans: relatives 725 +/- 101 vs controls 668 +/- 47/min; Asian: relatives 610 +/- 97 vs controls 783 +/- 936/min). Asian relatives had higher fasting circulating glycerol (65 +/- 7 vs 44 +/- 4 mumol/l, P < 0.05), non-esterified fatty acid (569 +/- 59 vs 375 +/- 64 mumol/l, P < 0.05) and 3-hydroxybutyrate levels (147 (44-187) vs 35 (21-57) mumol/l, P < 0.01) than their controls and this persisted following intravenous glucose. This difference was not observed in the European group. First-degree relatives of European patients with NIDDM possess early signs of beta-cell dysfunction, with increased and disproportionate secretion of 32,33 split proinsulin after intravenous glucose, whilst glucose tolerance is still normal.

Dynamics of the Seminal Vesicle Epithelium

In newborn rodents, seminal vesicle epithelium (SVEP) cells display a poorly developed rough endoplasmic reticulum (RER) and Golgi complex, and they show no signs of secretion. From puberty onward, secretory material starts to appear, and the RER and Golgi complex progressively develop and reorganize until the adult ultrastructure is established around 40-60 days of age. Multivesicular bodies and lysosomes follow in this development but lysosomes evolve to lipofucsin granules with aging. The duration of the secretory cycle in SVEP cells is shorter than in other exocrine cells and the secretory protein pattern depends on the animal species, androgen status, and sexual activity. SVEP cells are also involved in endocytosis, which is coupled to exocytosis, and their endocytic pathway intersects the exocytic pathway in Golgi cisterns. The structure and function of SVEP cells depends mainly on testosterone, but other hormones and factors, such as the neuropeptide VIP, also influence their activity. Castration leads to programmed death and regression of SVEP cells to an extent that depends on the animal species. In addition, castration induces changes in the secretory protein pattern and delays its intracellular transport. Endocytic kinetics is also delayed following castration. Primary cultures of SVEP cells in a bicameral system are proposed as a model to investigate the activities of SVEP cells further.

?There are secret signs we know, we two?: Echoes from homer in Jack Richardson'sThe Prodigal

A travers son adaptation du mythe d'Oreste dans The Prodigal J. Richardson nous presente une dramaturgie tragi-comique et meta-theatrale dans laquelle l'A. examine les reminiscences homeriques

The Three Tenses of Evgenii Rein "Was, Were, Was, Was, Was …"

It is an almost Kruchenykh-like incantation—the key to Evgenii Rein's poetry.1 As in any normal building, the key is not hidden from hypothetical robbers—it lies in full view or even dangles in the doorway, out of forgetfulness. A great deal about Rein's poems is simple, understandable, and accessible to anyone: look at it, like it, love it, repudiate it. As in any genuine poetry, though, what is most important is not its outward attributes but the overall atmosphere, the intonation, and the secret signs of fate the outsider does not know.

Subcutaneous Absorption Kinetics of Two Highly Concentrated Preparations of Recombinant Human Growth Hormone

The relative bioavailability of two highly concentrated (12 IU/ml) formulations of biosynthetic human growth hormone (GH) administered subcutaneously was compared. A randomized, crossover study. Conventional GH therapy was withdrawn 72 hours before each study period. There was a washout period of at least four weeks between the study periods. Participants were recruited from an outpatient clinic and were hospitalized during the two study periods. Fourteen GH-deficient patients (mean age 25.2 y, range 14-54). One patient was excluded from data analysis because of signs of endogenous GH secretion. At the start of each study period, GH 3 IU/m2 was injected subcutaneously. The two formulations, PenFill and PenSet, differ in the buffers used and in the relative content of mannitol and glycine. Serum profiles of GH were monitored frequently for 24 hours. Samples were taken every 30 minutes for 6 hours and then hourly. Bioavailability (F) and absorption dynamics of human GH were measured. The relative absorption fractions estimated from the areas under the individual serum concentration curves from 0 to 24 hours, and the observed time (Tmax) to reach the maximum concentration (Cmax) were determined. Short-term metabolic effects of GH on insulin-like growth factor (IGF-I), glucose, and insulin were determined. The geometric mean (SD) of F was 0.910 (1,236). The 90 percent confidence interval was 0.819-1.010. Mean (+/- SD) of Cmax was 12.65 +/- 5.89 and 12.58 +/- 4.40 ng/mL for PenFill and PenSet, respectively. Corresponding values for Tmax were 5.49 +/- 1.55 and 5.89 +/- 1.79 hours for PenFill and PenSet, respectively. There was a considerable interindividual variation, but the relative absorption fraction did not significantly differ from 1 (p = 0.13). Neither Cmax (p = 0.74) nor Tmax (p = 0.58) of the two formulations was significantly different. Injection of the two formulations induced similar increments in serum IFG-I (p = 0.48). Serum insulin and blood glucose concentrations were not significantly different. There is no significant difference between the absorption kinetics and short-term metabolic effects of these two highly concentrated formulations of biosynthetic GH. The two formulations are bioequivalent.

The Harderian gland of the Djungarian hamster (Phodopus sungorus): light- and electron-microscopical investigations.

The Harderian gland of the Djungarian hamster Phodopus sungorus was investigated by light and electron microscopy in adult animals of both sexes, held under either long or short photoperiods. These glands have a tubulo-alveolar structure. Epithelial cells were seen as small cylindric cells with a large, round nucleus located basally, many small vacuoles distributed throughout the cytoplasm (type I cells) or as rather broad cells with larger vacuoles (type II cells). The ratio of both cell types differed from 1:1 to 2:1 (type I:type II), regardless of the animal's sex. In the electron microscope, abundant smooth endoplasmic reticulum of the vesicular type and rod-like or oval-shaped mitochondria of the crista type were very numerous; while Golgi complexes were rarely seen. 'Membranous bodies' were about nine times higher in amount in type II cells and were further augmented fourfold, in number, in glands of female animals. The few bundles of poly-tubular structures that were observed, were predominantly in type I cells. Myoepithelial cells were linked to the basal part of acinar cells by interdigitations. Many microvilli were observed at the apical portion of cellular membranes. Acinar cells predominantly showed signs of merocrine secretion, although apocrine secretion was seen in some cases. Under epifluorescence, red porphyrin fluorescence was seen predominantly in type I cells, where it is mainly found apically. The comparison of animals held under either long or short photoperiods did not reveal any differences in Harderian gland structure.

Correlations between serum osmolality and endolymphatic sac response using hypertonic glycerol.

This study, using mice, correlated serum osmotic pressure, experimentally elevated with an intravenous injection of glycerol of varying tonicity (1.3, 2.6 and 5.2 g glycerol/kg body weight) with endolymphatic sac (ES) response. The injection produced a rise in serum osmotic pressure that was measured after 15 min (from 308 +/- 12.9 mosm/kg b.w. to 320 +/- 1.9, 353 +/- 19.3, 427 +/- 9.4 mosm/kg b.w., respectively). Normal levels were noted about 60 min after the injection. The ES was graphically displayed at 0 min, 1, 2 and 4 h using as a basis composite electron micrographs. The ES responded with signs of active secretion and degradation of macromolecular substances which appeared to be related to the rise in serum osmotic pressure. The study showed that the ES responds to glycerol injection with fine structural changes indicative of increased intra-epithelial synthesis of sugar/protein residues which are secreted and degraded within its lumen. The technique used made it possible to characterize the ultrastructural secretory pathways from the epithelial cells into the sac lumen. The results indicate that the ES may sense and respond to dynamic changes of the micro-osmotic environment probably via alterations in inner ear fluid homeostasis.

The Origins of Public Secrecy in Britain

The first modern crisis of public secrecy was set in motion in the Spring of 1844 when a little-known Italian exile began sending himself letters in which he had placed grains of sand, poppy seeds or fine hairs. The discovery that the additional contents were disappearing in transit confirmed Joseph Mazzini's suspicions that his correspondence was being opened by Sir James Graham, the Home Secretary, at the request of the Austrian ambassador. There then followed what Graham's first biographer described as a ‘paroxysm of national anger’ as the extent of clandestine domestic espionage was exposed. A powerful coalition of working-class radicals and Parliamentary Liberals came together to protest at the use of ‘the spy system of foreign states’.‘The proceeding cannot be English,’ thunderedThe Times, ‘any more than masks, poisons, sword-sticks, secret signs and associations, and other such dark ventures. Public opinion is mighty and jealous, and does not brook to hear of public ends pursued by other than public means. It considers that treason against its public self.’

The Epithelium of the Rabbit Vagina: A Microtopographical Study by Light, Transmission and Scanning Electron Microscopy.

In order to obtain a more precise microtopographical surface map of the epithelium of the rabbit vaginal mucosa, investigations by light microscopy (LM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) have been systematically correlated. The epithelium was examined from the "portio vaginalis cervicis uteri" down to the "vestibulum". This study shows that the upper 2/3 of the vagina--which, in this species, is very long, measuring 13-14 cm--is lined by a single epithelial layer of tall ciliated and microvillous cells closely resembling the endocervical epithelium with which it is continuous. Moreover, these ciliated and microvillous cells also cover mucosal infoldings in the upper part of the vagina, especially those on the ectocervix and in the fornices, and scattered vaginal crypts. In particular, the ciliated elements decrease in number below the fornices, so that in large areas of the middle part of the vagina only microvillous cells are recognizable. Prior to the squamo-columnar junction, however, the ciliated cells increase again. This study also reveals that in the rabbit the squamo-columnar junction is located at the level of the pubic symphysis and that a squamous pluristratified epithelium covers only the lower 1/3 of the inner surface of the vaginal wall. In the estrous, i.e., precoital rabbit, the microvillous cells show little sign of secretion, whereas after mating they exhibit remarkable secretory features. These seem to increase progressively with postcoital stages (5 h, 24 h and 10 days) in the form of extensive mucification. These secretions often come in contact with spermatozoa retained in the mucosal infoldings and crypts, and are similar to those occurring in the endometrium, where they clearly depend upon progesterone activity. These epithelial features, different from those of other mammals, including humans, suggest that the greater part of the rabbit vagina accomplishes functions other than serving for copulation and as a fetal passageway. The present findings support the view that the rabbit vagina also plays a role as a reservoir of spermatozoa and in maintaining their viability, like the endometrium and endocervix.

An asymptomatic, normotensive sipple syndrome patient with glucose intolerance and hypercholesterolemia, and her kindred.

The proband, a 42-year-old woman without any symptoms or hypertension, was admitted for examination of accidentally discovered bilateral adrenal masses. Physical examination disclosed bilateral nodular goiter and mild sinus tachycardia. Pheochromocytomas and medullary thyroid carcinomas were revealed by biochemical and histopathological examinations. Hypercholesterolemia and abnormal glucose metabolism returned to normal after bilateral total adrenalectomy and thyroidectomy. Screening examination showed four affected family members. Three of them were also asymptomatic and normotensive. In pheochromocytoma patients, normotension, hypercholesterolemia, and impaired glucose metabolism might be signs of excess secretion of epinephrine rather than norepinephrine.

Adrenal and Pituitary Emergencies

Although loss of normal pituitary function may be silent and asymptomatic, sudden loss of gland function (pituitary apoplexy) typically results in characteristic presentations. Sheehan's syndrome is the development of hypopituitarism after postpartum hemorrhage or shock. Patients with Sheehan's syndrome may have typical or atypical presentations based on the extent of pituitary gland destruction. Patients with typical symptoms fail to lactate after giving birth; subsequently these patients also develop symptoms and signs of hypopituitarism. Measuring the serum prolactin level after giving thyrotropin-releasing hormone is a reasonable first step in the diagnosis of this condition in patients who fail to lactate after giving birth. The diagnosis of hypopituitarism is delayed for up to 7 years in patients with atypical symptoms. Acute symptomatic failure of the pituitary gland (pituitary apoplexy) commonly occurs in patients who have asymptomatic pituitary tumors. Many patients with pituitary tumors do not have signs of abnormal endocrine gland secretion and have a normal appearance. Most patients have the following signs or symptoms: headache; acute disturbances in visual acuity or visual fields; ophthalmoplegia, and changes in the level of consciousness. The syndrome of pituitary apoplexy usually evolves over hours to days. Subarachnoid hemorrhage and acute bacterial meningitis are the two most important mimics of pituitary apoplexy. Intravenous steroids and prompt neurosurgical consultation are mandatory in cases of pituitary apoplexy since both steroids and surgery can improve vision. Testings for acute or chronic hypopituitarism is challenging in the Emergency Department setting; however, carefully chosen tests will aid in the subsequent early correct diagnosis after initial Emergency Department management.

Effects of anti-juvenile hormone agents and a juvenile hormone analog on neck-ligated post-feeding last instar larvae of Spodoptera mauritia Boisd. (Lepidoptera:Noctuidae)

The ability of three anti-juvenile hormone agents (AJHAs) to prevent the juvenile hormone dependent phase of larval-pupal transformation has been investigated. Neck-ligated post-feeding last instar larvae of Spodoptera mauritia were treated topically with different doses of a juvenile hormone analog (JHA) or the AJHAs, tetra-hydro-4-fluoromethyl-4-hydroxy-2H-pyran-2-one (FMev), ethyl-4-[2-(tert-butyl carbonyloxy)butoxy] benzoate (ETB) and ethyl-[E]-3-methyl-2-dodecanoate (EMD). Untreated ligated larvae or those treated with acetone survived for 12 ± 1 days without showing any sign of pupal cuticle secretion. On the other hand treatments of ligated larvae with different doses of JHA induced pupation. Among the three AJHAs tested treatments of ETB promoted pupation. Treatments of ligated larvae with lower doses of EMD induced the formation of larval-pupal intermediates whereas those treated with higher dose moulted into either pupae or larval-pupal intermediates. FMev-treated larvae exhibited a complete inhibition of moulting and metamorphosis. In order to study whether AJHAs would prevent the JHA induced pupation, neck-ligated larvae were treated simultaneously with different doses of AJHAs and 1μg JHA. Co-application of JHA with different doses of EMD induced pupation in majority of the ligated larvae and thus appears to a certain extent to counteract the effects of treatments of same doses of EMD alone. Co-application of JHA with different doses of ETB elicited pupation in all the surviving ligated larvae. To a large extent co-application of JHA with different doses of FMev failed to induce pupation. The significance of the findings is discussed in the context of the mode of action of these AJHAs. Les trois (AJHAs) ont ete examines son pouvoir qu’ empeche la transformation du Juvenile hormone dependent phase de larvaere-pupae. Ayant nourir derniere stade cou-ligatures larvaire de Spodoptera mauritia sont traite topicalement avec en doses differements du Juvenile hormone analog (JHA) ou AJHAs, tetra-hydro-4-fluoromethyl-4-hydroxy-2H-pyran-2-one (FMev), ethyl-4-[2-(tert-butyl carbonyloxy)butoxy] benzoate (ETB) et ethyl-[E]-3-methyl 2-dodecanoate (EMD). Non traite larvaire ligatures ou celles sont traite avec acetone survie pendant 12 ± 1 jours sans aucune signe de secretion par pupal cuticle. D’ailleurs traitement des larvaires ligatures avec en doses differents de JHA induit pupation. Parmi les larvaire deja traite par trois AJHAs sont induit pupation par ETB. Traitment des larvaires ligatures avec en doses inferieurs du EMD induit la formation de larvaires-pupal intermediares tandisque celles qui sont traites en doses superieurs mue a pupae ou larvaires pupal intermediares. Larvaires traites par FMev montre une inhibition complete du mue et metamorphosis. A fin d’etudier si AJHAs empechevont JHA induit pupation, cou-ligature larvaires sont traite simultanement avec en doses differents des AJHAs et 1μg JHA. En majorite des larvaires ligatures induit pupation par co-traitment de JHA avec en doses differents de EMD. Co-traitment de JHA avec en doses differents de ETB elicit pupation dans toutes les larvaires ligatures survivant. En plus part des cas co-traitment de JHA avec en doses differents de FMev n’induit pas la pupation. Les significances des resultats ont discutes d’une manniere de la mode d’action des AJHAs.

Quantitative monitoring of brain function, vital signs, and hormonal response during acute insulin-induced hypoglycemia

Acute insulin-induced hypoglycemia provokes changes in central nervous system activity and release of counterregulatory hormones. The clinical relationship between central nervous system activity, hormone secretion, and vital signs has not to our knowledge been previously reported. We used computerized electroencephalographic (CEEG) analysis to monitor 5 nondiabetic subjects during acute insulin-induced hypoglycemia (0.75 U/kg intravenous push). Their glucose nadir was 38 +/- 6 mg/dl (mean +/- 1 SD). A three-phase pattern of change in CEEG power in response to hypoglycemia was observed: phase 1 was characterized by an increase in total CEEG power (natural log of activity = 9.1 +/- 1.3 microV2) over baseline (8.7 +/- 1.2 microV2) in the theta, delta, and beta frequency bands. This phase preceded and coincided with the glucose nadir. During phase 2, power in all frequency bands fell significantly below baseline. A nadir in CEEG power (8.0 +/- 1.6 microV2) occurred 40 to 55 minutes after insulin injection as glucose levels were rising. During phase 3 there was a return to baseline in CEEG power and frequency spectra. Heart rate increase just before phase 1; peak heart rate (91 +/- 8 beats/min) coincided with peak CEEG power and was significantly higher than basal rate (71 +/- 11, P less than 0.05). A significant increase in respiratory rate occurred during phase 1 of the CEEG and persisted through phase 2. A significant decrease in mean blood pressure (nadir = 73 +/- 6 mm Hg) below preinsulin blood pressure (81 +/- 8 mm Hg, P less than 0.05) coincided with the nadir of CEEG power in phase 2.(ABSTRACT TRUNCATED AT 250 WORDS)

The endolymphatic sac and inner ear homeostasis. I: Effect of glycerol on the endolymphatic sac with or without colchicine pretreatment

The combined effects of glycerol and colchicine on the endolymphatic sac were investigated in mice. Glycerol induced signs of secretion from the epithelium with formation of secretory granules in the light epithelial cells. Other characteristics of the epithelial lining were also changed resulting in an increased widening of the lateral intercellular spaces, a partial collapse of the lumen and with a deposition of a stainable substance within the lumen. This reaction lasted from 30 min to 24 h following the injection. Pretreatment with colchicine was found to decrease or inhibit the glycerol-induced secretion of macromolecules into the sac. The lumen collapsed but frequently there was no presence of stainable substance. Animals treated with both glycerol and colchicine showed marked signs of inner ear malfunction which could indicate that the secretory activity in the sac might be closely related to the regulation of inner ear fluid homeostasis and that functional disturbances in this system may lead to disorders of inner ear function.

Peptidergic regulation of secretory activity in amphibian olfactory mucosa: Immunohistochemistry, neural stimulation, and pharmacology

The role of substance P in the regulation of secretion from sustentacular cells, Bowman's glands and deep glands in the amphibian olfactory mucosa was investigated using immunohistochemical, electrophysiological, and pharmacological methods. Substance P-like immunoreactive varicose fibers extended through the olfactory epithelium, terminating at or near the surface. In addition, immunoreactive varicose fibers innervated Bowman's glands, deep glands, and blood vessels in the lamina propria. Innervation of Bowman's gland was sparse, with fibers terminating on basal acinar cell membranes; deep gland innervation was abundant, with fibers often extending between acinar cells almost to the lumen. Stimulation of the ophthalmic branch of the trigeminal nerve resulted in slow potentials recorded at the surface of the olfactory epithelium. When the olfactory mucosae from trigeminal-stimulated animals were examined histologically, morphological signs of secretory activity were observed, suggesting that substance P was released from the trigeminal nerve terminals. Topical application of 10(-5) to 10(-3) mol substance P resulted in morphological signs of secretion that were very similar to those seen as a result of trigeminal stimulation. Thus, substance P released from trigeminal fibers may modulate secretory activity within the olfactory mucosa.

Ultrastructural characteristics of sustentacular cells in control and odorant-treated olfactory mucosae of the salamander.

The ultrastructural characteristics of five morphologically distinct regions of sustentacular cells in the salamander olfactory mucosa are described. 1) The apical region was characterized by a microvillar surface that lay below the level of the olfactory knob of olfactory receptor neurons and contained endosome-like vesicles and a filamentous array at the level of the zonula adherens. 2) The supranuclear region contained rough and smooth endoplasmic reticulum, a Golgi complex, and secretory vesicles. Few sustentacular cells showed morphological signs of secretion, suggesting a low rate of baseline secretory activity. 3) The nuclear region contained the cylindrical nucleus surrounded by a thin band of cytoplasm containing bundles of filaments. 4) The central stalk contained filamentous arrays, Golgi-like cisternae, multivesicular bodies, and peroxisomes. Cytoplasmic veils that extended from the central stalk contained filamentous aggregates. 5) The basilar expansion had a complex series of lateral and basal folds. The lateral folds enveloped extracellular material and nonmyelinated axons of the receptor neurons. The basal folds formed complex interdigitations with the basal lamina, particularly in regions occupied by blood vessels and the acini of Bowman's glands in the subjacent lamina propria. These characteristics, and the presence of endosome-like vesicles and mitochondria, suggest that the basilar expansion is metabolically active and participates in cellular transport of material. Treatment with the odorant 2-isobutyl-3-methoxypyrazine caused ultrastructural changes in the apical and supranuclear regions that were associated with secretion and in the basilar expansion region that were indicative of an increase in metabolic and transport activity.

Crosses and Carets: Renaissance Patronage and Coded Letters of Recommendation

IN THE VAST LITERATURE ON RENAISSANCE PATRONAGE, one problem seems to have escaped notice: the existence of letters of recommendation written by patrons on behalf of clients with the expectation that they be disregarded or given little consideration by the recipients. These letters bear all the marks of authenticity, including the autograph signatures of the writers, but they are spurious, because their purpose is to deceive the persons on whose behalf they are written.' They are distinguishable from other letters only by the presence or absence of secret signs or codes agreed on in advance by the correspondents. In some instances, patrons wrote letters recommending clients in the highest terms but sent other letters asking recipients not to honor the laudatory ones. More commonly, rulers instructed their ambassadors on the degree of support, if any, to be extended to their recommended clients at the courts of other rulers. All these letters, then, constitute a separate category from that of proforma or perfunctory recommendations, common in any age, which the recipients could readily interpret. The use of these deceptive practices by Duke Francesco Sforza of Milan and Cardinal Guillaume d'Estouteville of Rouen, two influential patrons in the middle of the fifteenth century, forms the subject of this article. It is not likely, however, that they originated the practice or were the only ones who made use of it. Perhaps

Scanning electron microscopy of the human endometrium in pill users.

AbstractTwenty premenstrual endometrial biopsies were examined in 20 fertile women using combined conventional oral contraceptive pills (Anovlar‐1) for periods from 1–15 years using both SEM and light microscopy. Three types of endometria were detected. These were, irregular secretory, suppressed and atrophic endometria. Using scanning electron microscopy the first type showed few ciliated cells with weak cilia as well as collapsed non‐ciliated cells. The second type showed non‐ciliated cells with few signs of secretion. The third type showed rarely ciliated cells, flat secretory cells with no signs of secretions. The longer the duration of pill usage the more were the atrophic changes. Focal glandular proliferation was also detected.

Thyroid development in the marsupial bandicoot, Isoodon macrourus.

The postnatal structural development of the thyroid gland of the Australian native bandicoot, Isoodon macrourus, was monitored and the onset of thyroid function (i.e., the secretion of thyroid hormones) was determined. Thyroid glands were obtained from bandicoots at days 1, 3, 11, 12, 13, 21, 25, 30, 34, 35, 39, 46, 48, 50, 59, 61, 75, 79, 83, and 163 of age and from adult animals, and the tissues were examined with the transmission electron microscope. The thyroid gland of the newborn bandicoot consisted of undifferentiated cells with no lumen. Follicles were first observed at day 12 postpartum, after which time rapid follicular growth occurred. The first signs of thyroid hormone secretion were seen at day 30 postpartum. A peak in thyroid activity seemed to occur around day 50 postpartum, and it correlated with the rapid rate of development of thermoregulatory capacity and hair development which occurred over the last 2 weeks of pouch life.