Langerhans cell histiocytosis of the thyroid mimicking thyroiditis in a boy: a case report and literature review

BACKGROUND

Langerhans cell histiocytosis affecting the thyroid commonly presents with nonspecific clinical and radiological manifestations. Thyroid Langerhans cell histiocytosis is typically characterized by non-enhancing hypodense lesions with an enlarged thyroid on computed tomography medical images. Thyroid involvement in LCH is uncommon and typically encountered in adults, as is salivary gland involvement. Therefore, we present a unique pediatric case featuring simultaneous salivary and thyroid involvement in LCH.

CASE PRESENTATION

A 3-year-old boy with complaints of an anterior neck mass persisting for 1 to 2 months, accompanied by mild pain, dysphagia, and hoarseness. A physical examination revealed a 2.5 cm firm and tender mass in the left anterior neck. Laboratory examinations revealed normal thyroid function test levels. Ultrasonography revealed multiple heterogeneous hypoechoic nodules with unclear and irregular margins in both lobes of the thyroid. Contrast-enhanced neck computed tomography revealed an enlarged thyroid gland and bilateral submandibular glands with non-enhancing hypointense nodular lesions, and multiple confluent thin-walled small (< 1.5 cm) cysts scattered bilaterally in the lungs. Subsequently, a left thyroid excisional biopsy was performed, leading to a histopathological diagnosis of LCH. Immunohistochemical analysis of the specimen demonstrated diffuse positivity for S-100, CD1a, and Langerin and focal positivity for CD68. The patient received standard therapy with vinblastine and steroid, and showed disease regression during regular follow-up of neck ultrasonography.

CONCLUSIONS

Involvement of the thyroid and submandibular gland as initial diagnosis of Langerhans cell histiocytosis is extremely rare. It is important to investigate the involvement of affected systems. A comprehensive survey and biopsy are required to establish a definitive diagnosis.

Klippel-Trénaunay syndrome with profound abdominal lymphatic-venous malformation in a three-day-old newborn: a case report and literature review

Background

Klippel-Trénaunay syndrome, a kind of congenital limb-length-discrepancy disorder, is commonly associated with a variety of vascular anomalies.

Case presentation

We present the case of a three-day-old newborn with a profound abdominal mass lesion during prenatal magnetic resonance imaging (MRI) examination. After delivery, physical examination revealed mild hemihypertrophy of the left lower extremity and red lesions on the left thigh. MRI of the abdomen showed a cyst-like lesion measuring 6.3 cm × 2.7 cm × 5.5 cm in the upper abdomen. Within the mass, there were also some possible calcified spots exhibiting high T1WI signals and low T2WI signals. A computed tomography (CT) scan of the abdomen was consistent with an ill-defined cystic tumor with small calcifications and encasement of mesenteric vessels. A MRI of the left lower extremity showed a tubular structure with a signal void and homogeneous strong enhancement located in the anterior subcutis of the left lower limb. The CT scan confirmed that the tubular structure was consistent with a venous malformation. This patient had features of Klippel-Trénaunay syndrome, including port-wine stains, a profound abdominal mass, and vascular malformations of the left lower extremity.

Conclusions

In this article, we presented a case of Klippel-Trénaunay syndrome, emphasizing both prenatal and confirmatory postnatal cross-sectional imaging findings. The rare presentation of an abdominal lymphatic-venous formation played a pivotal role as a crucial indicator for an early diagnosis of Klippel-Trénaunay syndrome.

A quantitative image analysis using MRI for diagnosis of biliary atresia

PURPOSE

Biliary atresia is a life-threatening disease that needs early diagnosis and management. Recently, MRI images have been used for the diagnosis of biliary atresia with improved accuracy of diagnosis when other imaging modalities such as ultrasonography are equivocal. This study aimed to evaluate the juxta-hilar extrahepatic biliary tree using MRI images to determine a quantitative value for diagnosing biliary atresia.

MATERIALS AND METHODS

This retrospective study was approved by the Ethical Committee at Mackey Memorial Hospital (IRB Number: 15MMHIS149e). Between January 2010 and December 2015, twenty-five patients with surgically confirmed biliary atresia were enrolled (age 18-65 days). Another 25 patients with clinically or surgically diagnosed idiopathic neonatal hepatitis (age 6-64 days) and 20 patients with non-hepatobiliary disease (age 6-65 days) were considered control group and normal subjects, respectively. The diameter of the enlarged, T2-hyperintense structure was measured using MRI images by two radiologists both blinded. The cut-off value for a biliary atresia diagnosis was obtained by area under the curve analysis.

RESULTS

The diameter of the T2-hyperintense structure at porta hepatis in biliary atresia (4.79 ± 1.14 mm) is larger than in idiopathic neonatal hepatitis (1.72 ± 0.42 mm) or in non-hepatobiliary disease (1.72 ± 0.35 mm) (p < 0.05). The optimum cut-off value for diagnosing biliary atresia was 3.1 mm with 98% sensitivity and 98% specificity.

CONCLUSION

The value of the enlarged, T2-hyperintense structure measured on MRI images was significantly increased in biliary atresia and may be useful in diagnosing biliary atresia.

Inverse metabolic engineering: A strategy for directed genetic engineering of useful phenotypes

The classical method of metabolic engineering, identifying a rate-determining step in a pathway and alleviating the bottleneck by enzyme overexpression, has motivated much research but has enjoyed only limited practical success. Intervention of other limiting steps, of counterbalancing regulation, and of unknown coupled pathways often confounds this direct approach. Here the concept of inverse metabolic engineering is codified and its application is illustrated with several examples. Inverse metabolic engineering means the elucidation of a metabolic engineering strategy by: first, identifying, constructing, or calculating a desired phenotype; second, determining the genetic or the particular environmental factors conferring that phenotype; and third, endowing that phenotype on another strain or organism by directed genetic or environmental manipulation. This paradigm has been successfully applied in several contexts, including elimination of growth factor requirements in mammalian cell culture and increasing the energetic efficiency of microaerobic bacterial respiration. (c) 1996 John Wiley & Sons, Inc.

Improvement of Escherichia coli microaerobic oxygen metabolism by Vitreoscilla hemoglobin: New insights from NAD(P)H fluorescence and culture redox potential

On-line NAD(P)H fluorescence and culture redox potential (CRP) measurements were utilized to investigate the role of Vitreoscilla hemoglobin (VHb) in perturbing oxygen metabolism of microaerobic Escherichia coli Batch cultures of a VHb-synthesizing E. coli strain and the iso-genic control under fully aerated conditions were subject to several high/low oxygen transitions, and the NAD(P)H fluorescence and CRP were monitored during these passages. The presence of VHb decreased the rate of net NAD(P)H generation by 2.4-fold under diminishing oxygen tension. In the absence of aeration, the strain producing VHb maintained a steady NAD(P)H level 1.8-fold less than that of the control, indicating that the presence of VHb keeps E. coli in a more oxidized state under oxygen-limited conditions. Estimated from CRP, the oxygen uptake rates near anoxia were 25% higher for cells with VHb than those without. These results suggest that VHb-expressing cells have a higher microaerobic electron transport chain turnover rate. To examine how NAD(P)H utilization of VHb-expressing cells responds to rapidly changing oxygen tension, which is common in large-scale fermentations, we pulsed air intermittently into a cell suspension and recorded the fluorescence response to the imposed dissolved oxygen (DO) fluctuation. Relative to the control, cells containing VHb had a sluggish fluorescence response to sudden changes of oxygen tension, suggesting that VHb buffers intracellular redox perturbations caused by extracellular DO fluctuations.(c) John Wiley & Sons, Inc.

Molecular kinetics of proteins at the surface of porcine sperm before and during fertilization

Fertilization is a decisive moment in life and enables the combination of the DNA from two gametes to ultimately form a new organism. The sperm surface, especially the head area, has distinguishable subdomains that are involved in distinct fertilization processes. It is known that the sperm head surface undergoes constant remodelling during epididymal maturation and migration in the male and female genital tract. But intriguingly, the identity, origin and spatial ordering of proteins at the sperm surface that are involved in mammalian fertilization are essentially unknown. This review deals with sperm surface protein modifications that are under somatic cell control. As soon as the sperm is released from the seminiferous tubules it is subjected to these modifications. These surface reorganisations continue until the sperm reside in the fallopian tube where they meet the oocyte and may fertilize it. Most likely, a selective process allows only functionally mature and intact sperm to optimally interact and fertilize the oocyte. Recent data suggest that even the perivitelline fluid is involved in sperm surface remodelling as it contains factors which could facilitate the first penetrating sperm to fertilize the oocyte. In this contribution, the kinetics of proteins at the sperm surface will be overviewed. Better understanding of this would help to design strategies to improve male fertility or to devise novel contraceptives.

Preparation of silica microspheres encapsulating phase-change material by sol-gel method in O/W emulsion

Spherical silica microcapsules containing phase-change material (PCM) were prepared by the sol-gel method in O/W emulsion. This is the first time that inorganic encapsulation of PCM with core/shell structure has been studied. The results of this synthesis revealed that micron size (4 - 8 microm) silica microspheres encapsulating n-pentadecane can be successfully created from acidic solutions ([H+] > or = 1.44 N) by using cationic surfactants as the emulsifiers. The identification of the mechanisms for the formation of silica shell at the oil-water interface indicates that it should be the charge-controlled mechanism through S+X-I+ (positively charged surfactant-halide ion-positively charged silica species) electrostatic interactions or the reaction rates-controlled mechanism working on cationic emulsifiers.

Bupivacaine inhibits COX-2 expression, PGE2, and cytokine production in endotoxin-activated macrophages

BACKGROUND

Upregulation of cyclooxygenase-2 (COX-2) and resultant prostaglandin E(2) (PGE(2)) overproduction has been shown to play a crucial role in initiating a systemic inflammatory response during sepsis. Sepsis also induces robust production of pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 as well as anti-inflammatory cytokine IL-10. We sought to elucidate the effects of bupivacaine on COX-2 expression and production of PGE(2) and cytokines using an endotoxin-activated murine macrophages model.

METHODS

Confluent murine macrophages (RAW264.7 cells) were treated with lipopolysaccharide (LPS, 100 ng/ml) or LPS plus bupivacaine (1, 10, or 100 microM). Bupivacaine was added immediately after LPS. After reacting for 18 h, cell cultures were harvested for subsequent analysis.

RESULTS

LPS significantly upregulated COX-2 transcription and PGE(2) production in macrophages. LPS also significantly increased the production of TNF-alpha, IL-1beta, IL-6 and IL-10 in macrophages. Bupivacaine significantly inhibited the effects of LPS on COX-2 transcription and PGE(2) production in a dose-dependent manner. In a dose-dependent manner, bupivacaine also significantly inhibited the effects of LPS on the production of TNF-alpha, IL-1beta, and IL-6. However, bupivacaine exerted no significant effects on LPS-induced IL-10 production.

CONCLUSION

Bupivacaine significantly inhibited COX-2 expression, PGE(2) and cytokine production in endotoxin-activated macrophages.

Proteomic analysis of human meibomian gland secretions

BACKGROUND/AIM

Human tears contain hundreds of proteins that may exert a significant influence on tear film stability, ocular surface integrity, and visual function. The authors hypothesise that many of these proteins originate from the meibomian gland. This study's aim was to begin to develop the proteomic methodology to permit the testing of their hypothesis.

METHODS

Meibomian gland secretions were collected from the lower eyelids of adult volunteers and placed in a chloroform-methanol mixture. Samples were partitioned in a biphasic system and non-lipid phase materials were reduced, alkylated, and trypsin digested to obtain peptides for protein identification. This peptide mixture was separated by micro-capillary reverse phase chromatography and the effluent examined by nano-electrospray MS and data dependent MS/MS. SEQUEST software was used to identify proteins from the MS/MS spectra.

RESULTS

The methodological approach to date has permitted the identification of more than 90 proteins in human meibomian gland secretions. Proteins include the alpha2-macroglobulin receptor, IgA alpha chain, farnesoid X activated receptor, interferon regulatory factor 3, lacritin precursor, lactotransferrin, lipocalin 1, lysozyme C precursor, potential phospholipid transporting ATPase IK, seven transmembrane helix receptor (also termed somatostatin receptor type 4), testes development related NYD-SP21 (also termed high affinity IgE receptor beta subunit), and TrkC tyrosine kinase.

CONCLUSIONS

These findings indicate that the meibomian gland secretes a number of proteins into the tear film. It is quite possible that these proteins contribute to the dynamics of the tear film in both health and disease.

The Effect of DNA Repair Defects on Reproductive Performance in Nucleotide Excision Repair (NER) Mouse Models: An Epidemiological Approach

In this study, we used an epidemiological approach to analyze an animal database of DNA repair deficient mice on reproductive performance in five Nucleotide Excision Repair (NER) mutant mouse models on a C57BL/6 genetic background, namely CSA, CSB, XPA, XPC [models for the human DNA repair disorders Cockayne Syndrome (CS) and xeroderma pigmentosum (XP), respectively] and mHR23B (not associated with human disease). This approach allowed us to detect and quantify reproductive effects based on a relatively small number of matings. We measured and quantified the scale of the effect between factors that might influence reproductive performance (i.e. age at co-housing, seasons) and reproductive parameters (i.e. litter size and pairing-to-birth interval -'pbi'). Besides, we detected and quantified the differences in reproductive performance between wild type mice and heterozygous/homozygous NER mutant mice. From our analyses, we found impaired reproduction in heterozygous and homozygous knock out mice; in particular, reduced litter size and lengthened pbi was related to the NER mutation-mHR23B, in heterozygous couples, even if they were otherwise phenotypically normal. Heterozygous mHR23B couples produced a 6.6-fold lower number of mHR23B(-/-) pups than indicated by Mendelian expectation; other genetic deficiencies studied were not statistically significant from each other or wild type controls. We concluded that careful epidemiological evaluations by analysis of animal database could provide reliable information on reproductive performance and detect deviations that would remain unnoticed without this. Also, some managerial aspects of mouse breeding could be evaluated.

Premedication with low-dose oral midazolam reduces the incidence and severity of emergence agitation in pediatric patients following sevoflurane anesthesia

BACKGROUND

Sevoflurane is a volatile anesthetic agent with low pungency, non-irritating odor, and low blood/gas partition coefficient that makes it an attractive alternative to halothane. However, a high incidence of emergence agitation (EA) has been reported in pediatric patients after sevoflurane anesthesia. The underlying mechanism of sevoflurane-induced EA remains unclear. Rapid recovery of consciousness (emergence) from sevoflurane anesthesia has been proposed as one possible mechanism. We, therefore, hypothesized that sedatives such as midazolam may counteract sevoflurane's rapid emergence and thus reduce the incidence and the severity of sevoflurane-induced EA.

METHODS

A prospective, controlled, single-blinded study was carried out in 88 ASA class I or II pediatric patients scheduled for elective outpatient surgery. Patients were assigned to receive either midazolam (oral midazolam, 0.2 mg/kg as anesthetic premedication) or saline (oral normal saline as premedication) before the conduct of anesthesia. When separation from parents was due its process was watched and evaluated. Induction of anesthesia and maintenance of anesthesia were uniform in both groups. Induction of anesthesia was made possible with 8% sevoflurane and N2O in 50% O2. Intubation was performed straight without the aid of muscle relaxant and the ventilator was set to maintain normocapnia. Anesthesia was maintained with 3% sevoflurane and N2O in 50% O2 until the surgery was over. All matters of relevant time periods were recorded (induction, surgical procedure, extubation and transportation). In the post-anesthesia care unit (PACU), adverse events, the incidence and the severity of EA, analgesic requirement, duration of PACU stay, and parental as well as PACU nurses' satisfaction were evaluated.

RESULTS

A significant lower incidence and less severity of EA were noted in patients premedicated with midazolam. Less postoperaive analgesia was required in patients who had received midazolam. Although midazolam-premedicated patients remained sedated after sevoflurane anesthesia, the duration of the PACU stay was not significantly different from that of saline-treated patients. Both parents and PACU nurses were more satisfied with midazolam as premedication. No solid evidence showed that there was close correlation between the process of separation from parents and the occurrence of EA.

CONCLUSIONS

Premedication with oral midazolam is safe, convenient and effective in decreasing the occurrence of sevoflurane-induced EA. It does not delay discharge from PACU and is suitable for outpatient surgery.

Noninvasive measurements of central arterial pressure and distensibility by arterial applanation tonometry with a generalized transfer function: implications for nursing

Decreased distensibility of large arteries is a strong indicator of cardiovascular risk. Measurements of arterial distensibility can be made noninvasively with the use of an arterial applanation pressure tonometer with a generalized transfer function. This article reviews (1) the concept of arterial distensibility and its relation to pulse wave amplitude, velocity, and reflection; (2) epidemiologic evidence that large-artery stiffness increases cardiovascular risks; and (3) the estimation of arterial distensibility with the use of noninvasive techniques, with an emphasis on measuring pulse wave velocity and calculating the aortic augmentation index. Finally, it addresses the application of arterial applanation tonometry in nursing research and practice.

Testosterone and estrogen act via different pathways to inhibit puberty in the male Siberian hamster (Phodopus sungorus)

The peripubertal transition in male mammals is accompanied by a gradual decrease in sensitivity to the inhibitory effects exerted by gonadal hormones, such as T and E2. Here, we investigated the effects of chronic T and its metabolites, 5alpha-dihydrotestosterone and E2 on the hypothalamo-pituitary-gonadal axis at puberty. We also examined if T effects are distinct or mediated through its conversion to 5alpha-dihydrotestosterone or E2. Twenty-day-old male Siberian hamsters were sc implanted with a SILASTIC brand capsule containing varying doses of T, 5alpha-dihydrotestosterone, or E2. Several functional parameters of the hypothalamo-pituitary-gonadal axis were evaluated including hypothalamic GnRH concentration, pituitary and plasma FSH levels, pituitary FSH and LH mRNA, and testicular status. Our results showed that gonadal steroids inhibited puberty in a dose-dependent manner as evaluated by testes mass (undiluted steroid: T, 27 +/- 3 mg; 5alpha-dihydrotestosterone, 18 +/- 1 mg; and E2, 62 +/- 4 mg relative to cholesterol-implanted controls, 510 +/- 42 mg). Also, T decreased plasma FSH below detectable levels, but pituitary FSH concentration was unaffected (1.37 +/- 0.16 ng/microg protein) while E2-treated hamsters had normal plasma FSH levels (3.5 +/- 0.98 ng/ml) yet significantly lower pituitary FSH concentration (0.09 +/- 0.04 ng/microg protein). These results showed that the pathways of T and E2 action on the hypothalamo-pituitary-gonadal axis are distinct.

Intrathecal magnesium sulfate attenuates algogenic behavior and spinal amino acids release after kainic acid receptor activation in rats

Activation of N-methyl-D-asparate (NMDA) receptor and non-NMDA classes of glutamate receptors play a key role in spinal nociceptive processing. Using with a lumbar intrathecal (IT) catheter and a loop dialysis catheter in lightly anesthetized (1% isoflurane) rats, the effect of IT pre-treatment with magnesium sulfate (100, 300 or 500 microg) on IT kainic acid (KA: 1 microg; non-NMDA receptor agonist) evoked amino acids (AAs) release and corresponding behavior was examined. IT KA produced significant increases (mean+/-SD of % baseline concentration) in dialysate concentrations of aspartate (424+/-88%), glutamate (241+/-35%) and taurine (398+/-58%). IT pre-treatment with MgSO(4) resulted in a dose-dependent suppression of the evoked algogenic behavior and aspartate release. These data suggest that activation of spinal KA receptors provides a powerful stimulus for secondary spinal excitatory AAs release and corresponding appearance of pain behavior. The regulation of this release by magnesium suggests the possible role of this divalent cation in regulating this excitatory effect of non-NMDA receptor activation.

Effects on the bispectral index during elective caesarean section: a comparison of propofol and isoflurane

BACKGROUND

Awareness during general anesthesia has been a particular problem during caesarean section. About 7 percent of patients undergoing elective caesarean section have reported dreaming or recall of voices during the procedure. The bispectral index (BIS), a value derived from the electroencephalogram (EEG), has been shown to be useful in monitoring the depth of anesthesia. Supplementation of propofol or isoflurane for maintenance of anesthesia has been shown to effectively reduce the incidence of awareness. However, the effects of propofol or isoflurane on the BIS index have not been fully investigated. We therefore designed this study to compare the effects of isoflurane or propofol supplementation on the BIS index in 24 healthy parturients undergoing elective caesarean section.

METHODS

All patients had induction of anesthesia and orotracheal intubation in rapid sequence made possible by 1 MAC isoflurane with 50% N2O-50% O2 as conveyer and atracurium. After delivery, patients were randomly assigned to either of two groups (isoflurane or propofol). Patients in the Isoflurane group (n = 12) received 0.5 MAC isoflurane in 67% N2O-33% O2 and fentanyl + droperidol. Patients in the propofol group (n = 12) received propofol (8 mg/kg/h) infusion combined with 67% N2O-33% O2 and fentanyl + droperidol.

RESULTS

There was no difference between the two groups in total operation time, maternal blood loss, fetal Apgar scores. No differences between the two groups in heart rate, blood pressure or BIS index values were found throughout the surgery. No patient from either group reported recall of the operative procedure. However, 25% of patients (3 of 12) in the isoflurane group had poor uterine contraction, suggestive of doubtful appropriateness of the use of isoflurane for maintenance of anesthesia in delivery.

CONCLUSIONS

We therefore concluded that supplementation of isoflurane or propofol for maintenance of anesthesia can satisfactorily decrease the BIS index and minimize the incidence of awareness in patients undergoing caesarean section under general anesthesia. The BIS index is a reliable monitor of the hypnotic component of anesthesia.

Biological and immunological characterization of multiple GnRH in an opisthobranch mollusk, Aplysia californica

Gonadotropin-releasing hormone (GnRH) is a neurohormone central to the regulation of reproductive functions in vertebrates. Recently, several studies have reported the presence of GnRH immunoreactivity (IR) in a number of mollusks, suggesting that the distribution of GnRH may not be restricted to Phylum Chordata. In the present study, we extend our investigations to an opisthobranch mollusk, Aplysia californica, to characterize the source, chemical nature, and biological activity of molluscan GnRH-related molecules. Specific radioimmunoassays (RIAs) of various tissue extracts of Aplysia revealed that only ovotestis, hemocytes, and hemolymph contained significant amounts of GnRH that crossreacts with antisera raised against tunicate-I (tI) and mammalian (m) GnRH. Further RIAs and extractions revealed that the GnRH-IR in the hemolymph is biochemically and immunologically distinct from the GnRH-IR in the hemocytes and ovotestis. Using reverse-phase high-performance liquid chromatography coupled with RIAs, the GnRH-IR in the hemolymph was resolved into two major peaks. The first peak eluted earlier than most known forms of vertebrate GnRH, and the later peak coeluted with m, lamprey I, chicken II, and tI-GnRH. However, both peaks were broad and may contain a heterogeneous mixture of GnRH-IR. Immunocytochemical study showed that tI-GnRH-IR was present in the connective sheath surrounding the central nervous system, with a strong presence in what appeared to be vascular space, again suggesting the close association between Aplysia GnRH-IR and circulation. Finally, treatment of the neuroendocrine bag cells with chicken II GnRH significantly decreased the duration of the afterdischarge (AD, a characteristic pattern of electrical firing in bag cell neurons) and the number of action potentials fired during an AD, indicating the presence of a corresponding GnRH receptor in the Aplysia central nervous system. Overall, the results demonstrated the presence of multiple forms of GnRH-IR that crossreact with tI- and mGnRH antisera in A. californica and the ability of a vertebrate GnRH to alter Aplysia neural activity. Together, these data suggest that GnRH may be a factor released by the ovotestis and hemocytes into the circulation to alter neural functions. GnRH-IR produced by the latter may serve as a novel mediator of the neural and immune functions in Aplysia.

Role of the cAMP signaling pathway in the regulation of gonadotropin-releasing hormone secretion in GT1 cells

We studied the signaling pathways coupling gonadotropin-releasing hormone (GnRH) secretion to elevations in cAMP levels in the GT1 GnRH-secreting neuronal cell line. We hypothesized that increased cAMP could be acting directly by means of cyclic nucleotide-gated (CNG) cation channels or indirectly by means of activation of cAMP-dependent protein kinase (PKA). We showed that GT1 cells express the three CNG subunits present in olfactory neurons (CNG2, -4.3, and -5) and exhibit functional cAMP-gated cation channels. Activation of PKA does not appear to be necessary for the stimulation of GnRH release by increased levels of cAMP. In fact, pharmacological inhibition of PKA activity caused an increase in the basal secretion of GnRH. Consistent with this observation activation PKA inhibited adenylyl cyclase activity, presumably by inhibiting adenylyl cyclase V expressed in the cells. Therefore, the stimulation of GnRH release by elevations in cAMP appears to be the result of depolarization of the neurons initiated by increased cation conductance by cAMP-gated cation channels. Activation of PKA may constitute a negative-feedback mechanisms for lowering cAMP levels. We hypothesize that these mechanisms could result in oscillations in cAMP levels, providing a biochemical basis for timing the pulsatile release of GnRH.

Postoperative myocardial infarction in a patient with perioperative ST-depression--a case report

Often we ignore electrocardiogram (EKG) evidence of ischemia and no adverse events occur. However, once in a while these ischemic episodes will turn into a full-blown myocardial infarction. Therefore, studying perioperative events which tilt the balance over to postoperative myocardial infarction (PMI) can enlighten our knowledge in postoperative myocardial infarction (MI) prevention. We present a case of ST depression in perioperative EKG evolving into postoperative MI. In this paper we attempt to explore various possibilities which could have altered this patient from her ischemic state into an infracted event.

Retinal hamartoma in oral-facial-digital syndrome

Only recently have intraocular findings been described in oral-facial-digital syndrome (OFDS), including 5 cases of chorioretinal colobomas and 1 case of optic nerve coloboma. We report a case of a new ocular anomaly associated with this syndrome: a retinal hamartoma in a male infant with OFDS. The patient had bilateral retinal masses that were suspicious for retinoblastoma because of a family history of retinoblastoma. Physical examination and imaging studies of the retinal masses could not differentiate between retinoblastoma, hamartoma, or persistent hyperplastic primary vitreous. Subsequent pathologic study of an enucleated globe was diagnostic of a retinal hamartoma. This case further illustrates the heterogeneity of ocular anomalies in OFDS and underscores the importance of a complete ophthalmologic evaluation in patients with this syndrome.

Children with mucopolysaccharidoses--three cases report

The mucopolysaccharidoses (MPS) are a group of inherited disorders of metabolism, with widespread, progressive involvement and derangement of many organs and tissues. Because of their disabling nature, frequent surgical intervention for the abnormality entailed is common, and is associated with a high degree of anesthetic risks perioperatively. One of the major hazards which we find clinically is airway difficulty. Multiple factors are present in the mucopolysaccharidoses to make airway management and trachael intubation potentially hazardous. Aside from generalized infiltration and thickening of the soft tissues, the oropharynx may be obstructed by a large tongue with tonsillar hypertrophy. Also, the friable mucosa covering the nasal and oral pharynx renders these structures easily to bleed and edematous. The neck is typically short and immobile, and the cervical spine and tempromandibular joint may have a limited range of movement. From our experience, we have learned not to overlook the propensity of airway difficulty. The uniqueness of their anatomy and extremely sensitive airway often result in failed intubation and bronchospasm even after successful intubation. Recently, in Mackay Memorial Hospital we have encountered in series three pediatric cases with mucopolysaccharidoses (one Hurler and two Hunter syndromes). In this report we would like to share our experiences and to discuss the anesthetic risks and management of the MPS patients.

Lidocaine concentrations in plasma and cerebrospinal fluid after systemic bolus administration in humans

Preclinical studies suggest that systemic lidocaine acts at the level of the spinal dorsal horn to inhibit hyperalgesia resulting from nerve injury, yet no clinical data are available to support this view. Therefore, we sought to characterize the time course of lidocaine in the plasma and cerebrospinal fluid (CSF) after an IV bolus injection of lidocaine 2 mg/kg in patients scheduled for surgery involving spinal anesthesia. Sixty-five patients were randomly allocated to one of five study groups (n = 13 per group) receiving IV lidocaine before CSF/ plasma sampling at 5, 10, 15, 30, or 60 min. Gas chromatographic analysis of these samples revealed a fast but transient peak (5-15 min) in lidocaine plasma levels (1.7+/-0.16 microg/mL), which declined rapidly thereafter. Only small concentrations of IV lidocaine were found in the CSF (6%- 8% of plasma concentration), but this fraction remained stable from 15 min until termination of the experiment. No statistical correlation was observed between plasma and CSF lidocaine levels. These data suggest that because of the prolonged availability of lidocaine at the spinal dorsal horn level, systemic administration of lidocaine suppresses central sensitization within the spinal cord after nerve injury in humans.

IMPLICATIONS

Cerebrospinal fluid concentrations of lidocaine after its systemic bolus delivery in humans indicate that the spinal cord may be the major site of antinociceptive action by this route of drug administration.

The comparative potency of intravenous nicardipine and verapamil on the cardiovascular response to tracheal intubation

BACKGROUND

Two different types of calcium channel blockers (namely nicardipine and verapamil) have been used widely in clinical practice. However, no clinical studies have previously been performed to ascertain the relative potency of intravenous verapamil and nicardipine in the attenuation of cardiovascular response to tracheal intubation.

METHODS

We assessed the optimal dose and relative potency of verapamil and nicardipine in the attenuation of hemodynamic response to tracheal intubation in 135 healthy patients. Control group (Group D received normal saline i.v. Patients in Groups II-V received nicardipine 0.005, 0.01, 0.03 and 0.06 mg/kg i.v., respectively. Patients in Groups VI-IX received verapamil 0.03, 0.05, 0.1 and 0.15 mg/kg i.v., respectively. Anaesthesia was induced with propofol (2.5 mg/kg) and muscle relaxation was facilitated by vecuronium (0.2 mg/kg, i.v.). One min after induction, tracheal intubation was performed. Mean arterial pressure (MAP) was measured at 1 min interval from 10 min before induction to 15 min after induction.

RESULTS

The ED50 with 95% confidence interval of nicardipine and verapamil for the attenuation of 50% mean arterial pressure (MAP) increase after tracheal intubation were 14.55 micrograms/kg (8.25-25.67) and 75.4 micrograms/kg (58.7-96.95), respectively. The ED50 with 95% confidence interval of verapamil for the reduction of the 50% heart rate (HR) increase post tracheal intubation was 57.4 micrograms/kg (18-182.2). No differences were found in the frequency of perioperative arrhythmia, post-operative hypotension, postoperative emesis, dizziness, muscle weakness and muscle soreness within two hours following surgery, when compared control with experimental groups (p > 0.05).

CONCLUSIONS

These results suggest that verapamil and nicardipine attenuate the hypertensive response to tracheal intubation without significant adverse effects in healthy patients. The dose ratio (ED50 nicardipine and ED50 verapamil for MAP) with 95% confidence interval was revealed to be 2.3 (1.82-7.41).

Expression of Vitreoscilla hemoglobin is superior to horse heart myoglobin or yeast flavohemoglobin expression for enhancing Escherichia coli growth in a microaerobic bioreactor

Expression of a gene encoding hemoglobin (VHb) from the aerobic bacterium Vitreoscilla sp. in several organisms, including Escherichia coli, has been shown to improve microaerobic cell growth and enhance oxygen-dependent product formation. The suitability of VHb to enhance microaerobic metabolism has been suggested to depend on its unusual oxygen binding characteristics. To examine whether hemoproteins of other origins can also elicit the positive effects VHb exerts in microaerobic E. coli cells, we subcloned the genes encoding Vitreoscilla VHb, horse heart myoglobin (HMb), and yeast flavohemoglobin (YFb) behind the IPTG-inducible tac promoter on a medium-copy-number vector and transformed these globin-expression plasmids into E. coli MG1655 and DH5 alpha. Biologically active VHb, HMb, and YFb were produced from these constructions in E. coli as judged by their ability to abduct carbon monoxide. The presence of HMb increased the growth of wild-type cells during the early stages of fed-batch growth, but the final optical densities of HMb-expressing cultures were comparable with the wild-type control not synthesizing HMb. The presence of VHb increased the cell density by 70% under the same cultivation conditions. The expression of wild-type YFb reduced the final cell density by 30% relative to the non-globin-expressing control.

Regulation of gonadotropin-releasing hormone neurons by basic fibroblast growth factor

The development of a functional network of gonadotropin-releasing hormone (GnRH) neurons in the central nervous system requires a series of complex regulatory mechanisms, presumably mediated in part by neurotrophic factors. The difficulty in studying factors regulating the development of GnRH neurons stems from their paucity and scattered distribution in the brain; as a result, little was known about the role of neurotrophic factors in the development of the mature GnRH neuronal network. Recent utilization of immortalized GnRH neuronal cell lines (GT1) has enabled us to identify and study specific neurotrophic factors and their functions in vitro. The potent neurotrophic effect of basic fibroblast growth factor (bFGF) and the presence of a high abundance of receptors for bFGF in GT1 cells have led to the hypothesis that bFGF may be an important regulator of GnRH neuron expansion, survival, migration, and connectivity.

Basic fibroblast growth factor is a neurotropic factor in GT1 gonadotropin-releasing hormone neuronal cell lines

Basic fibroblast growth factor (bFGF) plays an important role in development of the central nervous system and is neurotropic for a variety of neurons. In this study, we investigated whether bFGF is neurotropic for GT1 GnRH neuronal cell lines and if these cells express functional FGF receptors (FGFRs). The GT1 cell lines generated by genetically targeted tumorigenesis display highly differentiated properties of GnRH neurons. Addition of 2 and 10 ng/ml bFGF increased neurite outgrowth of GT1-7 cells and resulted in a significant increase of GT1 cell survival in serum-free medium. However, bFGF had no effect on [3H]thymidine incorporation at 24 or 48 h. RNase protection assays using riboprobes specific for murine FGFRs 1-3 showed that GT1 cells express FGFRs 1 and 3 but not 2. Occupancy of FGFRs with 10 ng/ml bFGF stimulated the sustained tyrosine phosphorylation of both the 42- and 44-kilodalton mitogen-activated protein kinases (MAPKs) for up to 6 h as shown by Western blot analysis. In addition, phosphorylation of the MAPKs was associated with enzyme activation as shown by an in-gel MAPK assay. GT1-1 and GT1-7 cells also express messenger RNA for bFGF, although the level of bioactive bFGF synthesized by GT1 cells appears suboptimal because GT1 cells can further respond to exogenously added bFGF. Thus, we have demonstrated that bFGF is a neurotropic factor in GT1 GnRh neuronal cell lines, raising the possibility that bFGF may play a role in the neurobiology of GnRH neurons.

Fnr, a global transcriptional regulator of Escherichia coli, activates the Vitreoscilla hemoglobin (VHb) promoter and intracellular VHb expression increases cytochrome d promoter activity

The oxygen-regulated promoter (Pvhb) of the Vitreoscilla hemoglobin gene has been applied to direct high-level expression of several cloned proteins, including Vitreoscilla hemoglobin (VHb), which improves productivity of many aerobic processes. In an effort to gain a better understanding of the regulation of Pvhb, and to guide further optimization of this technology, we investigated whether the Escherichia coli global regulatory molecules Fnr and the Arc system (ArcA and ArcB), which control the expression of various genes under either aerobic or anaerobic conditions, also regulate Pvhb activity in E. coli. The activity of Pvhb and the expression of VHb in E. coli were activated by Fnr, but were relatively unaffected by the Arc system under microaerobic conditions (DO less than 2% air saturation). We also examined the possibility of VHb affecting cytochrome d promoter activity during microaerobiosis. The presence of VHb increased the activity of beta-galactosidase from a cytochrome d promoter-lacZ fusion by 1.5-fold. This indicates that VHb affects oxygen-regulated transcription of E. coli genes and may contribute to the modified physiology observed in VHb-expressing E. coli.

The nature and distribution of gonadotropin-releasing hormones in brains and plasma of ranid frogs

Highly specific antisera and reversed-phase HPLC were used to examine the nature and distribution of gonadotropin-releasing hormone (GnRH) in the brains and plasma of three species of Rana frog previously reported to vary in the types and brain distributions of GnRH. The three species examined, Rana pipiens, Rana esculenta, and Rana ridibunda, exhibit differences in total concentration and relative concentrations of GnRH in brain areas, but all three contain the mammalian and chicken-II forms of GnRH (mGnRH and cGnRH-II). Both forms were found in the telencephalon and diencephalon, but mGnRH is consistently the most abundant form in the preoptic-hypothalamic area (e.g., ratios of mGnRH:cGnRH-II > 3:1 in hypothalamus-median eminence), whereas, cGnRH-II is the most abundant in the telencephalon and the only form measured in the cerebellum and medulla. The total content of cGnRH-II in the whole brain is about 1.5-2 times higher than that of mGnRH, due to the larger size of the areas outside the preoptic-hypothalamic area. These general patterns were the same for adults and juveniles. We found no evidence of a third form of GnRH corresponding to salmon GnRH in hypothalamus or other brain areas of R. esculenta as previously reported. These analyses also revealed the presence of both forms of GnRH in plasma draining the hypothalamic area, but the concentration of cGnRH-II is relatively higher than that in the corresponding hypothalamic tissue, suggesting differentially greater release or slower degradation of this form. These results do not support the conclusion that the ranid frogs are highly variable in the nature and distribution of GnRH in the brain, although they suggest that both forms of GnRH are potentially involved in the direct regulation of pituitary gonadotropes.

Intracellular expression of Vitreoscilla hemoglobin alters Escherichia coli energy metabolism under oxygen-limited conditions

An earlier stoichiometric analysis of oxygen-limited metabolism of Escherichia coli expressing cloned Vitreoscilla hemoglobin (VHb) suggested improved efficiency of ATP production relative to wild-type controls [Khosla, C., Curtis, J. E., DeModena, J., Rinas, J. & Bailey, J. E. (1990) BioTechnol. 8, 849-853]. This hypothesis has been further examined by determining several energetic parameters of different VHb-expressing E. coli (VHb+) strains relative to controls not expressing VHb (VHb-). The H+/O ratio, the transmembrane delta pH, and the ATP content of VHb+ constructs are 1.5, 1.6 and 2 times, respectively, corresponding values in VHb- controls. VHb was expressed using a low-copy-number vector in E. coli mutant strains lacking cytochrome o, cytochrome d, or both terminal oxidases; significant growth enhancement due to VHb expression was observed only in the strain having functional cytochrome o and lacking cytochrome d. All of these data obtained using different E. coli strains are consistent with a model of VHb action that hypothesizes enhancement by VHb of activity of the lower oxygen-affinity, higher proton-pumping-efficiency cytochrome o terminal oxidase under oxygen-limited growth conditions.

Role of aromatization in testosterone-induced inhibition of luteinizing hormone secretion in female turtles, Trachemys scripta

Both 17 beta-estradiol (E2) and testosterone (T) were shown to inhibit in vitro pituitary LH secretion in the turtle Trachemys scripta. Since T was approximately 500 times less potent than E2, and 5 alpha-dihydrotestosterone was even less active than T, the inhibitory action of T may result from its aromatization to estrogen. We utilized both in vivo and in vitro approaches to elucidate the roles of T and estrogen in the negative feedback of pituitary LH secretion. Gonadectomy of adult (vitellogenic) females significantly elevated plasma LH. Adult females treated with fadrozole (an aromatase inhibitor) with or without daily injections of keoxifene (an antiestrogen) also showed an increase in plasma LH to a level comparable to that observed in gonadectomized females, whereas plasma LH levels of juvenile females treated with fadrozole remained undetectable. In vitro LH secretion in response to GnRH in juvenile females was significantly inhibited by 48-h exposure to 50 ng/ml T or 100 pg/ml E2. Both fadrozole (200 microM) and keoxifene (200 nM) significantly blocked this T-induced inhibition of LH secretion, demonstrating that T lacks intrinsic inhibitory activity. Confirmation of the inhibition of aromatase activity by fadrozole comes from metabolic studies of 1 beta-[3H]androstenedione using turtle brain, ovary, and pituitary. In vitro, fadrozole altered the metabolism of 1 beta-[3H]androstenedione and inhibited aromatase activities in these tissues. These results indicate that the inhibitory effect of T is largely mediated through its aromatization to estrogen, and that estrogen is primarily responsible for the suppressed LH secretion in vitellogenic adult turtles.

[Anesthetic management of intraoperatively diagnosed pheochromocytoma--a case report]

Pheochromocytoma is a catecholamine secreting tumor originating from the adrenal medulla (up to 90%), or from the chromaffin tissue along the paravertebral sympathetic chain. The hallmark of pheochromocytoma is paroxysmal hypertension associated with diaphoresis, headache, tremulousness, and palpitations. The triad of diaphoresis, tachycardia, and headache in hypertensive patients is highly suggestive of pheochromocytoma. Other symptoms like flushing, nausea, vomiting, personality changes, and visual disturbances may however cast doubt on the diagnosis of pheochromocytoma. Death resulting from pheochromocytoma is usually due to congestive heart failure, myocardial infarction, or intracerebral hemorrhage. Although less than 0.1 percent of patients with hypertension have a pheochromocytoma, nearly 50 percent of the mortality with unsuspected pheochromocytoma occurred during anesthesia and surgery or parturition. Patients of unsuspected pheochromocytoma have higher risk for surgery, because some mandatory pre-op medical treatments might have been ignored. It is also a challenge to anesthesiologists to handle unsuspected hypertensive crisis during anesthesia and surgery. We presented such a case of unexpected Pheochromocytoma which was mis-diagnosed by the surgeon and was treated as an ordinary adrenal gland tumor and was scheduled for surgical operation. When the patient was undergoing excision of the tumor, manipulations of the tumor initiated an tremendous elevation of the blood pressure. Upon reviewing her history of normotension with visual disturbance, nausea and restlessness, she was immediate treated as with a pheochromocytoma. Appropriate managements were applied to control her abnormally high fluctuating blood pressure with success and with no complications or adverse effect.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo GnRH responsiveness of LH secretion in the female turtle, Trachemys scripta, in relation to the reproductive stage

The effects of several forms of gonadotropin-releasing hormone (GnRH) on the in vivo secretion of luteinizing hormone (LH) were investigated in the female turtle Trachemys scripta. Serial injections of large vitellogenic turtles with 1-2 micrograms (ca. 0.15 micrograms/100 g turtle) of chicken GnRH-I (cGnRH-I) and multiple blood sampling revealed that mature females were unresponsive to GnRH. In contrast, both forms of avian GnRH, cGnRH-I and cGnRH-II, and an avian GnRH analogue (GnRHa) significantly increased circulating levels of LH in previtellogenic turtles. In these turtles, plasma LH increased within 10 min after the initial injection of 0.5 microgram GnRHa or cGnRH-I, but this increase in LH was generally transient and could not be sustained for more than 2 hr even with repeated GnRH injections. Turtles treated with GnRHa on Day 1 showed attenuated pituitary responsiveness to subsequent GnRH challenges on Day 2, whereas turtles treated with both native forms of chicken GnRH remained equally responsive on Day 2. In vitro, GnRHa was more resistant to degradation in plasma than both native forms of GnRH, and the clearance rate of GnRHa in vivo was also slower than that of cGnRH-I. The results show, for the first time, that in vivo GnRH administration stimulates and desensitizes LH secretion in the turtles, but the GnRH responsiveness is related to reproductive status. Furthermore, the results suggest that the desensitizing effects of various forms of GnRH in vivo may be related to their clearance rate.

[Intrathecal meperidine attenuates shivering induced by spinal anesthesia]

Shivering is a common and complex phenomenon that occurs in many patients during spinal anesthesia. Shivering can increase oxygen consumption up to 500 per cent which may be detrimental to patients with decreased myocardial reserve. The metabolic costs and cardiorespiratory consequences of shivering are important particularly for patients with anemia, coronary arterial disease, cardiopulmonary insufficient, debilitated status or are elderly. We studied whether intrathecal meperidine could prevent shivering after spinal anesthesia. 60 patients with ASA class I-II were divided into intrathecal meperidine group (Group I) (n = 30) and control group (Group II) (n = 30). Group I received spinal tetracaine 12-16 mg with meperidine 0.2 mg/kg and Group II received spinal tetracaine 12-16 mg without meperidine. During operation the highest level of spinal anesthesia, ambient and rectal temperatures, blood pressure (BP) and heart rate (HR), presence or absence of shivering, intensity of shivering in both groups were recorded. Close observation for side effects was given post-operatively. There was a significant reduction (p < .005) in incidence of shivering in group I patients (16.7%) when compared with group II (56.7%). There was no or less side effects observed with other neuraxial opioids except nausea. We concluded that intrathecal meperidine could suppress shivering induced by spinal anesthesia.

Differential distribution of chicken-I and chicken-II GnRH in the turtle brain

Chicken-I and chicken-II gonadotropin-releasing hormone (cI-GnRH and cII-GnRH) were shown to be differentially distributed in the brain of a turtle, Trachemys scripta, by HPLC and specific radioimmunoassays. The cI-GnRH was most concentrated in the median eminence (ME), while cII-GnRH was most concentrated in the caudal brain regions, especially medulla and cerebellum. The ratio of cI- to cII-GnRH in the ME of adults was 8:1. Age- and sex-related differences in GnRH concentrations were observed exclusively in the ME: adult females had significantly higher cI-GnRH than younger females and adult males; adult females also had significantly higher cII-GnRH than hatching females. Their differential distribution and sex- and age-related differences suggest that the two peptides may have distinct physiological roles; cI-GnRH is likely the form responsible for stimulating gonadotropin release.

GnRH-induced desensitization of in vitro luteinizing hormone secretion in the turtle, Trachemys scripta

Gonadotropin-releasing hormone (GnRH)-induced desensitization of pituitary luteinizing hormone (LH) secretion in female turtles (Trachemys scripta) was investigated by in vitro superfusion of whole or hemipituitaries with the endogenous forms of the peptide. In sub-adults, LH secretion was rapidly attenuated (desensitized) by both prolonged and pulsatile treatments of chicken II GnRH (cII-GnRH), but pulsatile GnRH administration was more effective than prolonged administration in stimulating LH release. Prolonged administration of chicken I GnRH (cI-GnRH) also desensitized LH secretion; cI-GnRH was slightly less potent than cII-GnRH. GnRH-induced attenuation of LH secretion was not the result of tissue deterioration or depletion of releasable LH: GnRH responsiveness of desensitized pituitaries was fully restored after 4 hr of in vitro recovery, and further LH secretion was induced by tetraethylammonium chloride, a membrane depolarizing agent, in the desensitized glands; TRH-stimulated TSH release did not show desensitization in the same glands. Pituitaries from most adult (vitellogenic) females failed to respond to GnRH challenges; however, when responsive, adult pituitaries also desensitized under prolonged GnRH stimulation and were more resistant to GnRH-induced desnsitization under pulsatile GnRH treatments. Current results show that adult T. scripta typically display lower GnRH sensitivity than the subadults; the latter are like mammals, birds, and goldfish in their susceptibility to desensitization by both forms of endogenous GnRH.

Estrogen-independent growth of mouse vaginal epithelium in organ culture

A serum-free vaginal explant culture system was established to investigate the in vitro effect of estrogen on the growth of mouse vaginal epithelium. Vaginal explants were isolated from 40-day-old, ovariectomized BALB/cCrgl mice and cultured in a basal unsupplemented medium or in basal medium plus various doses of 17 beta-estradiol. Explants were processed for histology at the end of culture periods or were given 4-hour pulses of tritiated thymidine at various times and processed for autoradiography. Vaginal epithelium increased 3- to 5-fold in thickness and 2-fold in the number of epithelial cell layers during 72 hours of culture without estrogen; addition of estrogen did not significantly influence epithelial growth. Keratinization of vaginal epithelium occurred within 48 hours of culture in the absence of estrogen, and again addition of estrogen did not accelerate its appearance. Covering the explants with collagen decreased the estrogen-independent growth of vaginal epithelium. Autoradiography showed that ca. 70-90% of basal epithelial cells entered S phase during the initial 4 hours of culture and that this number declined rapidly after 48 hours to ca. 20%. Addition of 1.8 nM 17 beta-estradiol significantly decreased the labelling index of basal cells at 48 hours, but did not affect the labelling index at 24 and 72 hours. Stromal cells were not labelled at any time. Thus, DNA synthesis, cellular proliferation, and differentiation (keratinization) of vaginal epithelium in organ culture occurred without estrogen and were not stimulated by the addition of estrogen.

Proliferation and differentiation of prepubertal mouse vaginal epithelial cells in vitro and the specificity of estrogen-induced growth retardation

Mouse vaginal epithelial cells were isolated from intact 21-day-old BALB/cCrgl mice and cultured in a serum-free medium (SF20: basal medium supplemented with insulin, epidermal growth factor, transferrin, and bovine serum albumin--fraction V) to examine the proliferation, differentiation, and specificity of estrogen-induced growth retardation in vitro. Histologic and ultrastructural studies showed that vaginal epithelial cells undergo differentiative changes in vitro in the absence of estrogen, and that these changes are similar to those induced in vivo by estrogen. Addition of 17 beta-estradiol inhibited cellular proliferation in a dose-dependent manner. Whereas other estrane derivatives (17 alpha-estradiol and estriol) also significantly retarded cellular proliferation, cholesterol, testosterone, and progesterone had no effect. Keoxifene, an antiestrogen, significantly reversed estrogen-induced growth inhibition, resulting in proliferation of estrogen-treated cells equivalent to that of the untreated control. The results suggest that both proliferation and differentiation of prepubertal mouse vaginal epithelial cells in vitro are estrogen-independent, and that the growth inhibition is a specific estrogen-induced response.

High-pressure liquid chromatographic determination of saccharin in artificial sweeteners and pharmaceuticals

A high-pressure liquid chromatographic procedure is presented for determining saccharin in various formulations. The method is fast, precise, and accurate and is specific for saccharin in the presence of its most likely impurities and degradation products. Reversed-phase chromatography on a micro-C18 column is utilized with an internal standard, and detection is by UV absorption at 280 nm.